Bug Summary

File:tools/clang/lib/AST/ExprConstant.cpp
Warning:line 9623, column 3
Called C++ object pointer is null

Annotated Source Code

1//===--- ExprConstant.cpp - Expression Constant Evaluator -----------------===//
2//
3// The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// This file implements the Expr constant evaluator.
11//
12// Constant expression evaluation produces four main results:
13//
14// * A success/failure flag indicating whether constant folding was successful.
15// This is the 'bool' return value used by most of the code in this file. A
16// 'false' return value indicates that constant folding has failed, and any
17// appropriate diagnostic has already been produced.
18//
19// * An evaluated result, valid only if constant folding has not failed.
20//
21// * A flag indicating if evaluation encountered (unevaluated) side-effects.
22// These arise in cases such as (sideEffect(), 0) and (sideEffect() || 1),
23// where it is possible to determine the evaluated result regardless.
24//
25// * A set of notes indicating why the evaluation was not a constant expression
26// (under the C++11 / C++1y rules only, at the moment), or, if folding failed
27// too, why the expression could not be folded.
28//
29// If we are checking for a potential constant expression, failure to constant
30// fold a potential constant sub-expression will be indicated by a 'false'
31// return value (the expression could not be folded) and no diagnostic (the
32// expression is not necessarily non-constant).
33//
34//===----------------------------------------------------------------------===//
35
36#include "clang/AST/APValue.h"
37#include "clang/AST/ASTContext.h"
38#include "clang/AST/ASTDiagnostic.h"
39#include "clang/AST/ASTLambda.h"
40#include "clang/AST/CharUnits.h"
41#include "clang/AST/Expr.h"
42#include "clang/AST/RecordLayout.h"
43#include "clang/AST/StmtVisitor.h"
44#include "clang/AST/TypeLoc.h"
45#include "clang/Basic/Builtins.h"
46#include "clang/Basic/TargetInfo.h"
47#include "llvm/Support/raw_ostream.h"
48#include <cstring>
49#include <functional>
50
51using namespace clang;
52using llvm::APSInt;
53using llvm::APFloat;
54
55static bool IsGlobalLValue(APValue::LValueBase B);
56
57namespace {
58 struct LValue;
59 struct CallStackFrame;
60 struct EvalInfo;
61
62 static QualType getType(APValue::LValueBase B) {
63 if (!B) return QualType();
64 if (const ValueDecl *D = B.dyn_cast<const ValueDecl*>())
65 return D->getType();
66
67 const Expr *Base = B.get<const Expr*>();
68
69 // For a materialized temporary, the type of the temporary we materialized
70 // may not be the type of the expression.
71 if (const MaterializeTemporaryExpr *MTE =
72 dyn_cast<MaterializeTemporaryExpr>(Base)) {
73 SmallVector<const Expr *, 2> CommaLHSs;
74 SmallVector<SubobjectAdjustment, 2> Adjustments;
75 const Expr *Temp = MTE->GetTemporaryExpr();
76 const Expr *Inner = Temp->skipRValueSubobjectAdjustments(CommaLHSs,
77 Adjustments);
78 // Keep any cv-qualifiers from the reference if we generated a temporary
79 // for it directly. Otherwise use the type after adjustment.
80 if (!Adjustments.empty())
81 return Inner->getType();
82 }
83
84 return Base->getType();
85 }
86
87 /// Get an LValue path entry, which is known to not be an array index, as a
88 /// field or base class.
89 static
90 APValue::BaseOrMemberType getAsBaseOrMember(APValue::LValuePathEntry E) {
91 APValue::BaseOrMemberType Value;
92 Value.setFromOpaqueValue(E.BaseOrMember);
93 return Value;
94 }
95
96 /// Get an LValue path entry, which is known to not be an array index, as a
97 /// field declaration.
98 static const FieldDecl *getAsField(APValue::LValuePathEntry E) {
99 return dyn_cast<FieldDecl>(getAsBaseOrMember(E).getPointer());
100 }
101 /// Get an LValue path entry, which is known to not be an array index, as a
102 /// base class declaration.
103 static const CXXRecordDecl *getAsBaseClass(APValue::LValuePathEntry E) {
104 return dyn_cast<CXXRecordDecl>(getAsBaseOrMember(E).getPointer());
105 }
106 /// Determine whether this LValue path entry for a base class names a virtual
107 /// base class.
108 static bool isVirtualBaseClass(APValue::LValuePathEntry E) {
109 return getAsBaseOrMember(E).getInt();
110 }
111
112 /// Given a CallExpr, try to get the alloc_size attribute. May return null.
113 static const AllocSizeAttr *getAllocSizeAttr(const CallExpr *CE) {
114 const FunctionDecl *Callee = CE->getDirectCallee();
115 return Callee ? Callee->getAttr<AllocSizeAttr>() : nullptr;
116 }
117
118 /// Attempts to unwrap a CallExpr (with an alloc_size attribute) from an Expr.
119 /// This will look through a single cast.
120 ///
121 /// Returns null if we couldn't unwrap a function with alloc_size.
122 static const CallExpr *tryUnwrapAllocSizeCall(const Expr *E) {
123 if (!E->getType()->isPointerType())
124 return nullptr;
125
126 E = E->IgnoreParens();
127 // If we're doing a variable assignment from e.g. malloc(N), there will
128 // probably be a cast of some kind. Ignore it.
129 if (const auto *Cast = dyn_cast<CastExpr>(E))
130 E = Cast->getSubExpr()->IgnoreParens();
131
132 if (const auto *CE = dyn_cast<CallExpr>(E))
133 return getAllocSizeAttr(CE) ? CE : nullptr;
134 return nullptr;
135 }
136
137 /// Determines whether or not the given Base contains a call to a function
138 /// with the alloc_size attribute.
139 static bool isBaseAnAllocSizeCall(APValue::LValueBase Base) {
140 const auto *E = Base.dyn_cast<const Expr *>();
141 return E && E->getType()->isPointerType() && tryUnwrapAllocSizeCall(E);
142 }
143
144 /// Determines if an LValue with the given LValueBase will have an unsized
145 /// array in its designator.
146 /// Find the path length and type of the most-derived subobject in the given
147 /// path, and find the size of the containing array, if any.
148 static unsigned
149 findMostDerivedSubobject(ASTContext &Ctx, APValue::LValueBase Base,
150 ArrayRef<APValue::LValuePathEntry> Path,
151 uint64_t &ArraySize, QualType &Type, bool &IsArray) {
152 // This only accepts LValueBases from APValues, and APValues don't support
153 // arrays that lack size info.
154 assert(!isBaseAnAllocSizeCall(Base) &&((!isBaseAnAllocSizeCall(Base) && "Unsized arrays shouldn't appear here"
) ? static_cast<void> (0) : __assert_fail ("!isBaseAnAllocSizeCall(Base) && \"Unsized arrays shouldn't appear here\""
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 155, __PRETTY_FUNCTION__))
155 "Unsized arrays shouldn't appear here")((!isBaseAnAllocSizeCall(Base) && "Unsized arrays shouldn't appear here"
) ? static_cast<void> (0) : __assert_fail ("!isBaseAnAllocSizeCall(Base) && \"Unsized arrays shouldn't appear here\""
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 155, __PRETTY_FUNCTION__))
;
156 unsigned MostDerivedLength = 0;
157 Type = getType(Base);
158
159 for (unsigned I = 0, N = Path.size(); I != N; ++I) {
160 if (Type->isArrayType()) {
161 const ConstantArrayType *CAT =
162 cast<ConstantArrayType>(Ctx.getAsArrayType(Type));
163 Type = CAT->getElementType();
164 ArraySize = CAT->getSize().getZExtValue();
165 MostDerivedLength = I + 1;
166 IsArray = true;
167 } else if (Type->isAnyComplexType()) {
168 const ComplexType *CT = Type->castAs<ComplexType>();
169 Type = CT->getElementType();
170 ArraySize = 2;
171 MostDerivedLength = I + 1;
172 IsArray = true;
173 } else if (const FieldDecl *FD = getAsField(Path[I])) {
174 Type = FD->getType();
175 ArraySize = 0;
176 MostDerivedLength = I + 1;
177 IsArray = false;
178 } else {
179 // Path[I] describes a base class.
180 ArraySize = 0;
181 IsArray = false;
182 }
183 }
184 return MostDerivedLength;
185 }
186
187 // The order of this enum is important for diagnostics.
188 enum CheckSubobjectKind {
189 CSK_Base, CSK_Derived, CSK_Field, CSK_ArrayToPointer, CSK_ArrayIndex,
190 CSK_This, CSK_Real, CSK_Imag
191 };
192
193 /// A path from a glvalue to a subobject of that glvalue.
194 struct SubobjectDesignator {
195 /// True if the subobject was named in a manner not supported by C++11. Such
196 /// lvalues can still be folded, but they are not core constant expressions
197 /// and we cannot perform lvalue-to-rvalue conversions on them.
198 unsigned Invalid : 1;
199
200 /// Is this a pointer one past the end of an object?
201 unsigned IsOnePastTheEnd : 1;
202
203 /// Indicator of whether the first entry is an unsized array.
204 unsigned FirstEntryIsAnUnsizedArray : 1;
205
206 /// Indicator of whether the most-derived object is an array element.
207 unsigned MostDerivedIsArrayElement : 1;
208
209 /// The length of the path to the most-derived object of which this is a
210 /// subobject.
211 unsigned MostDerivedPathLength : 28;
212
213 /// The size of the array of which the most-derived object is an element.
214 /// This will always be 0 if the most-derived object is not an array
215 /// element. 0 is not an indicator of whether or not the most-derived object
216 /// is an array, however, because 0-length arrays are allowed.
217 ///
218 /// If the current array is an unsized array, the value of this is
219 /// undefined.
220 uint64_t MostDerivedArraySize;
221
222 /// The type of the most derived object referred to by this address.
223 QualType MostDerivedType;
224
225 typedef APValue::LValuePathEntry PathEntry;
226
227 /// The entries on the path from the glvalue to the designated subobject.
228 SmallVector<PathEntry, 8> Entries;
229
230 SubobjectDesignator() : Invalid(true) {}
231
232 explicit SubobjectDesignator(QualType T)
233 : Invalid(false), IsOnePastTheEnd(false),
234 FirstEntryIsAnUnsizedArray(false), MostDerivedIsArrayElement(false),
235 MostDerivedPathLength(0), MostDerivedArraySize(0),
236 MostDerivedType(T) {}
237
238 SubobjectDesignator(ASTContext &Ctx, const APValue &V)
239 : Invalid(!V.isLValue() || !V.hasLValuePath()), IsOnePastTheEnd(false),
240 FirstEntryIsAnUnsizedArray(false), MostDerivedIsArrayElement(false),
241 MostDerivedPathLength(0), MostDerivedArraySize(0) {
242 assert(V.isLValue() && "Non-LValue used to make an LValue designator?")((V.isLValue() && "Non-LValue used to make an LValue designator?"
) ? static_cast<void> (0) : __assert_fail ("V.isLValue() && \"Non-LValue used to make an LValue designator?\""
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 242, __PRETTY_FUNCTION__))
;
243 if (!Invalid) {
244 IsOnePastTheEnd = V.isLValueOnePastTheEnd();
245 ArrayRef<PathEntry> VEntries = V.getLValuePath();
246 Entries.insert(Entries.end(), VEntries.begin(), VEntries.end());
247 if (V.getLValueBase()) {
248 bool IsArray = false;
249 MostDerivedPathLength = findMostDerivedSubobject(
250 Ctx, V.getLValueBase(), V.getLValuePath(), MostDerivedArraySize,
251 MostDerivedType, IsArray);
252 MostDerivedIsArrayElement = IsArray;
253 }
254 }
255 }
256
257 void setInvalid() {
258 Invalid = true;
259 Entries.clear();
260 }
261
262 /// Determine whether the most derived subobject is an array without a
263 /// known bound.
264 bool isMostDerivedAnUnsizedArray() const {
265 assert(!Invalid && "Calling this makes no sense on invalid designators")((!Invalid && "Calling this makes no sense on invalid designators"
) ? static_cast<void> (0) : __assert_fail ("!Invalid && \"Calling this makes no sense on invalid designators\""
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 265, __PRETTY_FUNCTION__))
;
266 return Entries.size() == 1 && FirstEntryIsAnUnsizedArray;
267 }
268
269 /// Determine what the most derived array's size is. Results in an assertion
270 /// failure if the most derived array lacks a size.
271 uint64_t getMostDerivedArraySize() const {
272 assert(!isMostDerivedAnUnsizedArray() && "Unsized array has no size")((!isMostDerivedAnUnsizedArray() && "Unsized array has no size"
) ? static_cast<void> (0) : __assert_fail ("!isMostDerivedAnUnsizedArray() && \"Unsized array has no size\""
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 272, __PRETTY_FUNCTION__))
;
273 return MostDerivedArraySize;
274 }
275
276 /// Determine whether this is a one-past-the-end pointer.
277 bool isOnePastTheEnd() const {
278 assert(!Invalid)((!Invalid) ? static_cast<void> (0) : __assert_fail ("!Invalid"
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 278, __PRETTY_FUNCTION__))
;
279 if (IsOnePastTheEnd)
280 return true;
281 if (!isMostDerivedAnUnsizedArray() && MostDerivedIsArrayElement &&
282 Entries[MostDerivedPathLength - 1].ArrayIndex == MostDerivedArraySize)
283 return true;
284 return false;
285 }
286
287 /// Check that this refers to a valid subobject.
288 bool isValidSubobject() const {
289 if (Invalid)
290 return false;
291 return !isOnePastTheEnd();
292 }
293 /// Check that this refers to a valid subobject, and if not, produce a
294 /// relevant diagnostic and set the designator as invalid.
295 bool checkSubobject(EvalInfo &Info, const Expr *E, CheckSubobjectKind CSK);
296
297 /// Update this designator to refer to the first element within this array.
298 void addArrayUnchecked(const ConstantArrayType *CAT) {
299 PathEntry Entry;
300 Entry.ArrayIndex = 0;
301 Entries.push_back(Entry);
302
303 // This is a most-derived object.
304 MostDerivedType = CAT->getElementType();
305 MostDerivedIsArrayElement = true;
306 MostDerivedArraySize = CAT->getSize().getZExtValue();
307 MostDerivedPathLength = Entries.size();
308 }
309 /// Update this designator to refer to the first element within the array of
310 /// elements of type T. This is an array of unknown size.
311 void addUnsizedArrayUnchecked(QualType ElemTy) {
312 PathEntry Entry;
313 Entry.ArrayIndex = 0;
314 Entries.push_back(Entry);
315
316 MostDerivedType = ElemTy;
317 MostDerivedIsArrayElement = true;
318 // The value in MostDerivedArraySize is undefined in this case. So, set it
319 // to an arbitrary value that's likely to loudly break things if it's
320 // used.
321 MostDerivedArraySize = std::numeric_limits<uint64_t>::max() / 2;
322 MostDerivedPathLength = Entries.size();
323 }
324 /// Update this designator to refer to the given base or member of this
325 /// object.
326 void addDeclUnchecked(const Decl *D, bool Virtual = false) {
327 PathEntry Entry;
328 APValue::BaseOrMemberType Value(D, Virtual);
329 Entry.BaseOrMember = Value.getOpaqueValue();
330 Entries.push_back(Entry);
331
332 // If this isn't a base class, it's a new most-derived object.
333 if (const FieldDecl *FD = dyn_cast<FieldDecl>(D)) {
334 MostDerivedType = FD->getType();
335 MostDerivedIsArrayElement = false;
336 MostDerivedArraySize = 0;
337 MostDerivedPathLength = Entries.size();
338 }
339 }
340 /// Update this designator to refer to the given complex component.
341 void addComplexUnchecked(QualType EltTy, bool Imag) {
342 PathEntry Entry;
343 Entry.ArrayIndex = Imag;
344 Entries.push_back(Entry);
345
346 // This is technically a most-derived object, though in practice this
347 // is unlikely to matter.
348 MostDerivedType = EltTy;
349 MostDerivedIsArrayElement = true;
350 MostDerivedArraySize = 2;
351 MostDerivedPathLength = Entries.size();
352 }
353 void diagnosePointerArithmetic(EvalInfo &Info, const Expr *E, uint64_t N);
354 /// Add N to the address of this subobject.
355 void adjustIndex(EvalInfo &Info, const Expr *E, uint64_t N) {
356 if (Invalid) return;
357 if (isMostDerivedAnUnsizedArray()) {
358 // Can't verify -- trust that the user is doing the right thing (or if
359 // not, trust that the caller will catch the bad behavior).
360 Entries.back().ArrayIndex += N;
361 return;
362 }
363 if (MostDerivedPathLength == Entries.size() &&
364 MostDerivedIsArrayElement) {
365 Entries.back().ArrayIndex += N;
366 if (Entries.back().ArrayIndex > getMostDerivedArraySize()) {
367 diagnosePointerArithmetic(Info, E, Entries.back().ArrayIndex);
368 setInvalid();
369 }
370 return;
371 }
372 // [expr.add]p4: For the purposes of these operators, a pointer to a
373 // nonarray object behaves the same as a pointer to the first element of
374 // an array of length one with the type of the object as its element type.
375 if (IsOnePastTheEnd && N == (uint64_t)-1)
376 IsOnePastTheEnd = false;
377 else if (!IsOnePastTheEnd && N == 1)
378 IsOnePastTheEnd = true;
379 else if (N != 0) {
380 diagnosePointerArithmetic(Info, E, uint64_t(IsOnePastTheEnd) + N);
381 setInvalid();
382 }
383 }
384 };
385
386 /// A stack frame in the constexpr call stack.
387 struct CallStackFrame {
388 EvalInfo &Info;
389
390 /// Parent - The caller of this stack frame.
391 CallStackFrame *Caller;
392
393 /// Callee - The function which was called.
394 const FunctionDecl *Callee;
395
396 /// This - The binding for the this pointer in this call, if any.
397 const LValue *This;
398
399 /// Arguments - Parameter bindings for this function call, indexed by
400 /// parameters' function scope indices.
401 APValue *Arguments;
402
403 // Note that we intentionally use std::map here so that references to
404 // values are stable.
405 typedef std::map<const void*, APValue> MapTy;
406 typedef MapTy::const_iterator temp_iterator;
407 /// Temporaries - Temporary lvalues materialized within this stack frame.
408 MapTy Temporaries;
409
410 /// CallLoc - The location of the call expression for this call.
411 SourceLocation CallLoc;
412
413 /// Index - The call index of this call.
414 unsigned Index;
415
416 CallStackFrame(EvalInfo &Info, SourceLocation CallLoc,
417 const FunctionDecl *Callee, const LValue *This,
418 APValue *Arguments);
419 ~CallStackFrame();
420
421 APValue *getTemporary(const void *Key) {
422 MapTy::iterator I = Temporaries.find(Key);
423 return I == Temporaries.end() ? nullptr : &I->second;
424 }
425 APValue &createTemporary(const void *Key, bool IsLifetimeExtended);
426 };
427
428 /// Temporarily override 'this'.
429 class ThisOverrideRAII {
430 public:
431 ThisOverrideRAII(CallStackFrame &Frame, const LValue *NewThis, bool Enable)
432 : Frame(Frame), OldThis(Frame.This) {
433 if (Enable)
434 Frame.This = NewThis;
435 }
436 ~ThisOverrideRAII() {
437 Frame.This = OldThis;
438 }
439 private:
440 CallStackFrame &Frame;
441 const LValue *OldThis;
442 };
443
444 /// A partial diagnostic which we might know in advance that we are not going
445 /// to emit.
446 class OptionalDiagnostic {
447 PartialDiagnostic *Diag;
448
449 public:
450 explicit OptionalDiagnostic(PartialDiagnostic *Diag = nullptr)
451 : Diag(Diag) {}
452
453 template<typename T>
454 OptionalDiagnostic &operator<<(const T &v) {
455 if (Diag)
456 *Diag << v;
457 return *this;
458 }
459
460 OptionalDiagnostic &operator<<(const APSInt &I) {
461 if (Diag) {
462 SmallVector<char, 32> Buffer;
463 I.toString(Buffer);
464 *Diag << StringRef(Buffer.data(), Buffer.size());
465 }
466 return *this;
467 }
468
469 OptionalDiagnostic &operator<<(const APFloat &F) {
470 if (Diag) {
471 // FIXME: Force the precision of the source value down so we don't
472 // print digits which are usually useless (we don't really care here if
473 // we truncate a digit by accident in edge cases). Ideally,
474 // APFloat::toString would automatically print the shortest
475 // representation which rounds to the correct value, but it's a bit
476 // tricky to implement.
477 unsigned precision =
478 llvm::APFloat::semanticsPrecision(F.getSemantics());
479 precision = (precision * 59 + 195) / 196;
480 SmallVector<char, 32> Buffer;
481 F.toString(Buffer, precision);
482 *Diag << StringRef(Buffer.data(), Buffer.size());
483 }
484 return *this;
485 }
486 };
487
488 /// A cleanup, and a flag indicating whether it is lifetime-extended.
489 class Cleanup {
490 llvm::PointerIntPair<APValue*, 1, bool> Value;
491
492 public:
493 Cleanup(APValue *Val, bool IsLifetimeExtended)
494 : Value(Val, IsLifetimeExtended) {}
495
496 bool isLifetimeExtended() const { return Value.getInt(); }
497 void endLifetime() {
498 *Value.getPointer() = APValue();
499 }
500 };
501
502 /// EvalInfo - This is a private struct used by the evaluator to capture
503 /// information about a subexpression as it is folded. It retains information
504 /// about the AST context, but also maintains information about the folded
505 /// expression.
506 ///
507 /// If an expression could be evaluated, it is still possible it is not a C
508 /// "integer constant expression" or constant expression. If not, this struct
509 /// captures information about how and why not.
510 ///
511 /// One bit of information passed *into* the request for constant folding
512 /// indicates whether the subexpression is "evaluated" or not according to C
513 /// rules. For example, the RHS of (0 && foo()) is not evaluated. We can
514 /// evaluate the expression regardless of what the RHS is, but C only allows
515 /// certain things in certain situations.
516 struct LLVM_ALIGNAS(/*alignof(uint64_t)*/ 8)alignas(8) EvalInfo {
517 ASTContext &Ctx;
518
519 /// EvalStatus - Contains information about the evaluation.
520 Expr::EvalStatus &EvalStatus;
521
522 /// CurrentCall - The top of the constexpr call stack.
523 CallStackFrame *CurrentCall;
524
525 /// CallStackDepth - The number of calls in the call stack right now.
526 unsigned CallStackDepth;
527
528 /// NextCallIndex - The next call index to assign.
529 unsigned NextCallIndex;
530
531 /// StepsLeft - The remaining number of evaluation steps we're permitted
532 /// to perform. This is essentially a limit for the number of statements
533 /// we will evaluate.
534 unsigned StepsLeft;
535
536 /// BottomFrame - The frame in which evaluation started. This must be
537 /// initialized after CurrentCall and CallStackDepth.
538 CallStackFrame BottomFrame;
539
540 /// A stack of values whose lifetimes end at the end of some surrounding
541 /// evaluation frame.
542 llvm::SmallVector<Cleanup, 16> CleanupStack;
543
544 /// EvaluatingDecl - This is the declaration whose initializer is being
545 /// evaluated, if any.
546 APValue::LValueBase EvaluatingDecl;
547
548 /// EvaluatingDeclValue - This is the value being constructed for the
549 /// declaration whose initializer is being evaluated, if any.
550 APValue *EvaluatingDeclValue;
551
552 /// The current array initialization index, if we're performing array
553 /// initialization.
554 uint64_t ArrayInitIndex = -1;
555
556 /// HasActiveDiagnostic - Was the previous diagnostic stored? If so, further
557 /// notes attached to it will also be stored, otherwise they will not be.
558 bool HasActiveDiagnostic;
559
560 /// \brief Have we emitted a diagnostic explaining why we couldn't constant
561 /// fold (not just why it's not strictly a constant expression)?
562 bool HasFoldFailureDiagnostic;
563
564 /// \brief Whether or not we're currently speculatively evaluating.
565 bool IsSpeculativelyEvaluating;
566
567 enum EvaluationMode {
568 /// Evaluate as a constant expression. Stop if we find that the expression
569 /// is not a constant expression.
570 EM_ConstantExpression,
571
572 /// Evaluate as a potential constant expression. Keep going if we hit a
573 /// construct that we can't evaluate yet (because we don't yet know the
574 /// value of something) but stop if we hit something that could never be
575 /// a constant expression.
576 EM_PotentialConstantExpression,
577
578 /// Fold the expression to a constant. Stop if we hit a side-effect that
579 /// we can't model.
580 EM_ConstantFold,
581
582 /// Evaluate the expression looking for integer overflow and similar
583 /// issues. Don't worry about side-effects, and try to visit all
584 /// subexpressions.
585 EM_EvaluateForOverflow,
586
587 /// Evaluate in any way we know how. Don't worry about side-effects that
588 /// can't be modeled.
589 EM_IgnoreSideEffects,
590
591 /// Evaluate as a constant expression. Stop if we find that the expression
592 /// is not a constant expression. Some expressions can be retried in the
593 /// optimizer if we don't constant fold them here, but in an unevaluated
594 /// context we try to fold them immediately since the optimizer never
595 /// gets a chance to look at it.
596 EM_ConstantExpressionUnevaluated,
597
598 /// Evaluate as a potential constant expression. Keep going if we hit a
599 /// construct that we can't evaluate yet (because we don't yet know the
600 /// value of something) but stop if we hit something that could never be
601 /// a constant expression. Some expressions can be retried in the
602 /// optimizer if we don't constant fold them here, but in an unevaluated
603 /// context we try to fold them immediately since the optimizer never
604 /// gets a chance to look at it.
605 EM_PotentialConstantExpressionUnevaluated,
606
607 /// Evaluate as a constant expression. Continue evaluating if either:
608 /// - We find a MemberExpr with a base that can't be evaluated.
609 /// - We find a variable initialized with a call to a function that has
610 /// the alloc_size attribute on it.
611 /// In either case, the LValue returned shall have an invalid base; in the
612 /// former, the base will be the invalid MemberExpr, in the latter, the
613 /// base will be either the alloc_size CallExpr or a CastExpr wrapping
614 /// said CallExpr.
615 EM_OffsetFold,
616 } EvalMode;
617
618 /// Are we checking whether the expression is a potential constant
619 /// expression?
620 bool checkingPotentialConstantExpression() const {
621 return EvalMode == EM_PotentialConstantExpression ||
622 EvalMode == EM_PotentialConstantExpressionUnevaluated;
623 }
624
625 /// Are we checking an expression for overflow?
626 // FIXME: We should check for any kind of undefined or suspicious behavior
627 // in such constructs, not just overflow.
628 bool checkingForOverflow() { return EvalMode == EM_EvaluateForOverflow; }
629
630 EvalInfo(const ASTContext &C, Expr::EvalStatus &S, EvaluationMode Mode)
631 : Ctx(const_cast<ASTContext &>(C)), EvalStatus(S), CurrentCall(nullptr),
632 CallStackDepth(0), NextCallIndex(1),
633 StepsLeft(getLangOpts().ConstexprStepLimit),
634 BottomFrame(*this, SourceLocation(), nullptr, nullptr, nullptr),
635 EvaluatingDecl((const ValueDecl *)nullptr),
636 EvaluatingDeclValue(nullptr), HasActiveDiagnostic(false),
637 HasFoldFailureDiagnostic(false), IsSpeculativelyEvaluating(false),
638 EvalMode(Mode) {}
639
640 void setEvaluatingDecl(APValue::LValueBase Base, APValue &Value) {
641 EvaluatingDecl = Base;
642 EvaluatingDeclValue = &Value;
643 }
644
645 const LangOptions &getLangOpts() const { return Ctx.getLangOpts(); }
646
647 bool CheckCallLimit(SourceLocation Loc) {
648 // Don't perform any constexpr calls (other than the call we're checking)
649 // when checking a potential constant expression.
650 if (checkingPotentialConstantExpression() && CallStackDepth > 1)
651 return false;
652 if (NextCallIndex == 0) {
653 // NextCallIndex has wrapped around.
654 FFDiag(Loc, diag::note_constexpr_call_limit_exceeded);
655 return false;
656 }
657 if (CallStackDepth <= getLangOpts().ConstexprCallDepth)
658 return true;
659 FFDiag(Loc, diag::note_constexpr_depth_limit_exceeded)
660 << getLangOpts().ConstexprCallDepth;
661 return false;
662 }
663
664 CallStackFrame *getCallFrame(unsigned CallIndex) {
665 assert(CallIndex && "no call index in getCallFrame")((CallIndex && "no call index in getCallFrame") ? static_cast
<void> (0) : __assert_fail ("CallIndex && \"no call index in getCallFrame\""
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 665, __PRETTY_FUNCTION__))
;
666 // We will eventually hit BottomFrame, which has Index 1, so Frame can't
667 // be null in this loop.
668 CallStackFrame *Frame = CurrentCall;
669 while (Frame->Index > CallIndex)
670 Frame = Frame->Caller;
671 return (Frame->Index == CallIndex) ? Frame : nullptr;
672 }
673
674 bool nextStep(const Stmt *S) {
675 if (!StepsLeft) {
676 FFDiag(S->getLocStart(), diag::note_constexpr_step_limit_exceeded);
677 return false;
678 }
679 --StepsLeft;
680 return true;
681 }
682
683 private:
684 /// Add a diagnostic to the diagnostics list.
685 PartialDiagnostic &addDiag(SourceLocation Loc, diag::kind DiagId) {
686 PartialDiagnostic PD(DiagId, Ctx.getDiagAllocator());
687 EvalStatus.Diag->push_back(std::make_pair(Loc, PD));
688 return EvalStatus.Diag->back().second;
689 }
690
691 /// Add notes containing a call stack to the current point of evaluation.
692 void addCallStack(unsigned Limit);
693
694 private:
695 OptionalDiagnostic Diag(SourceLocation Loc, diag::kind DiagId,
696 unsigned ExtraNotes, bool IsCCEDiag) {
697
698 if (EvalStatus.Diag) {
699 // If we have a prior diagnostic, it will be noting that the expression
700 // isn't a constant expression. This diagnostic is more important,
701 // unless we require this evaluation to produce a constant expression.
702 //
703 // FIXME: We might want to show both diagnostics to the user in
704 // EM_ConstantFold mode.
705 if (!EvalStatus.Diag->empty()) {
706 switch (EvalMode) {
707 case EM_ConstantFold:
708 case EM_IgnoreSideEffects:
709 case EM_EvaluateForOverflow:
710 if (!HasFoldFailureDiagnostic)
711 break;
712 // We've already failed to fold something. Keep that diagnostic.
713 case EM_ConstantExpression:
714 case EM_PotentialConstantExpression:
715 case EM_ConstantExpressionUnevaluated:
716 case EM_PotentialConstantExpressionUnevaluated:
717 case EM_OffsetFold:
718 HasActiveDiagnostic = false;
719 return OptionalDiagnostic();
720 }
721 }
722
723 unsigned CallStackNotes = CallStackDepth - 1;
724 unsigned Limit = Ctx.getDiagnostics().getConstexprBacktraceLimit();
725 if (Limit)
726 CallStackNotes = std::min(CallStackNotes, Limit + 1);
727 if (checkingPotentialConstantExpression())
728 CallStackNotes = 0;
729
730 HasActiveDiagnostic = true;
731 HasFoldFailureDiagnostic = !IsCCEDiag;
732 EvalStatus.Diag->clear();
733 EvalStatus.Diag->reserve(1 + ExtraNotes + CallStackNotes);
734 addDiag(Loc, DiagId);
735 if (!checkingPotentialConstantExpression())
736 addCallStack(Limit);
737 return OptionalDiagnostic(&(*EvalStatus.Diag)[0].second);
738 }
739 HasActiveDiagnostic = false;
740 return OptionalDiagnostic();
741 }
742 public:
743 // Diagnose that the evaluation could not be folded (FF => FoldFailure)
744 OptionalDiagnostic
745 FFDiag(SourceLocation Loc,
746 diag::kind DiagId = diag::note_invalid_subexpr_in_const_expr,
747 unsigned ExtraNotes = 0) {
748 return Diag(Loc, DiagId, ExtraNotes, false);
749 }
750
751 OptionalDiagnostic FFDiag(const Expr *E, diag::kind DiagId
752 = diag::note_invalid_subexpr_in_const_expr,
753 unsigned ExtraNotes = 0) {
754 if (EvalStatus.Diag)
755 return Diag(E->getExprLoc(), DiagId, ExtraNotes, /*IsCCEDiag*/false);
756 HasActiveDiagnostic = false;
757 return OptionalDiagnostic();
758 }
759
760 /// Diagnose that the evaluation does not produce a C++11 core constant
761 /// expression.
762 ///
763 /// FIXME: Stop evaluating if we're in EM_ConstantExpression or
764 /// EM_PotentialConstantExpression mode and we produce one of these.
765 OptionalDiagnostic CCEDiag(SourceLocation Loc, diag::kind DiagId
766 = diag::note_invalid_subexpr_in_const_expr,
767 unsigned ExtraNotes = 0) {
768 // Don't override a previous diagnostic. Don't bother collecting
769 // diagnostics if we're evaluating for overflow.
770 if (!EvalStatus.Diag || !EvalStatus.Diag->empty()) {
771 HasActiveDiagnostic = false;
772 return OptionalDiagnostic();
773 }
774 return Diag(Loc, DiagId, ExtraNotes, true);
775 }
776 OptionalDiagnostic CCEDiag(const Expr *E, diag::kind DiagId
777 = diag::note_invalid_subexpr_in_const_expr,
778 unsigned ExtraNotes = 0) {
779 return CCEDiag(E->getExprLoc(), DiagId, ExtraNotes);
780 }
781 /// Add a note to a prior diagnostic.
782 OptionalDiagnostic Note(SourceLocation Loc, diag::kind DiagId) {
783 if (!HasActiveDiagnostic)
784 return OptionalDiagnostic();
785 return OptionalDiagnostic(&addDiag(Loc, DiagId));
786 }
787
788 /// Add a stack of notes to a prior diagnostic.
789 void addNotes(ArrayRef<PartialDiagnosticAt> Diags) {
790 if (HasActiveDiagnostic) {
791 EvalStatus.Diag->insert(EvalStatus.Diag->end(),
792 Diags.begin(), Diags.end());
793 }
794 }
795
796 /// Should we continue evaluation after encountering a side-effect that we
797 /// couldn't model?
798 bool keepEvaluatingAfterSideEffect() {
799 switch (EvalMode) {
800 case EM_PotentialConstantExpression:
801 case EM_PotentialConstantExpressionUnevaluated:
802 case EM_EvaluateForOverflow:
803 case EM_IgnoreSideEffects:
804 return true;
805
806 case EM_ConstantExpression:
807 case EM_ConstantExpressionUnevaluated:
808 case EM_ConstantFold:
809 case EM_OffsetFold:
810 return false;
811 }
812 llvm_unreachable("Missed EvalMode case")::llvm::llvm_unreachable_internal("Missed EvalMode case", "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 812)
;
813 }
814
815 /// Note that we have had a side-effect, and determine whether we should
816 /// keep evaluating.
817 bool noteSideEffect() {
818 EvalStatus.HasSideEffects = true;
819 return keepEvaluatingAfterSideEffect();
820 }
821
822 /// Should we continue evaluation after encountering undefined behavior?
823 bool keepEvaluatingAfterUndefinedBehavior() {
824 switch (EvalMode) {
825 case EM_EvaluateForOverflow:
826 case EM_IgnoreSideEffects:
827 case EM_ConstantFold:
828 case EM_OffsetFold:
829 return true;
830
831 case EM_PotentialConstantExpression:
832 case EM_PotentialConstantExpressionUnevaluated:
833 case EM_ConstantExpression:
834 case EM_ConstantExpressionUnevaluated:
835 return false;
836 }
837 llvm_unreachable("Missed EvalMode case")::llvm::llvm_unreachable_internal("Missed EvalMode case", "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 837)
;
838 }
839
840 /// Note that we hit something that was technically undefined behavior, but
841 /// that we can evaluate past it (such as signed overflow or floating-point
842 /// division by zero.)
843 bool noteUndefinedBehavior() {
844 EvalStatus.HasUndefinedBehavior = true;
845 return keepEvaluatingAfterUndefinedBehavior();
846 }
847
848 /// Should we continue evaluation as much as possible after encountering a
849 /// construct which can't be reduced to a value?
850 bool keepEvaluatingAfterFailure() {
851 if (!StepsLeft)
852 return false;
853
854 switch (EvalMode) {
855 case EM_PotentialConstantExpression:
856 case EM_PotentialConstantExpressionUnevaluated:
857 case EM_EvaluateForOverflow:
858 return true;
859
860 case EM_ConstantExpression:
861 case EM_ConstantExpressionUnevaluated:
862 case EM_ConstantFold:
863 case EM_IgnoreSideEffects:
864 case EM_OffsetFold:
865 return false;
866 }
867 llvm_unreachable("Missed EvalMode case")::llvm::llvm_unreachable_internal("Missed EvalMode case", "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 867)
;
868 }
869
870 /// Notes that we failed to evaluate an expression that other expressions
871 /// directly depend on, and determine if we should keep evaluating. This
872 /// should only be called if we actually intend to keep evaluating.
873 ///
874 /// Call noteSideEffect() instead if we may be able to ignore the value that
875 /// we failed to evaluate, e.g. if we failed to evaluate Foo() in:
876 ///
877 /// (Foo(), 1) // use noteSideEffect
878 /// (Foo() || true) // use noteSideEffect
879 /// Foo() + 1 // use noteFailure
880 LLVM_NODISCARD[[clang::warn_unused_result]] bool noteFailure() {
881 // Failure when evaluating some expression often means there is some
882 // subexpression whose evaluation was skipped. Therefore, (because we
883 // don't track whether we skipped an expression when unwinding after an
884 // evaluation failure) every evaluation failure that bubbles up from a
885 // subexpression implies that a side-effect has potentially happened. We
886 // skip setting the HasSideEffects flag to true until we decide to
887 // continue evaluating after that point, which happens here.
888 bool KeepGoing = keepEvaluatingAfterFailure();
889 EvalStatus.HasSideEffects |= KeepGoing;
890 return KeepGoing;
891 }
892
893 bool allowInvalidBaseExpr() const {
894 return EvalMode == EM_OffsetFold;
895 }
896
897 class ArrayInitLoopIndex {
898 EvalInfo &Info;
899 uint64_t OuterIndex;
900
901 public:
902 ArrayInitLoopIndex(EvalInfo &Info)
903 : Info(Info), OuterIndex(Info.ArrayInitIndex) {
904 Info.ArrayInitIndex = 0;
905 }
906 ~ArrayInitLoopIndex() { Info.ArrayInitIndex = OuterIndex; }
907
908 operator uint64_t&() { return Info.ArrayInitIndex; }
909 };
910 };
911
912 /// Object used to treat all foldable expressions as constant expressions.
913 struct FoldConstant {
914 EvalInfo &Info;
915 bool Enabled;
916 bool HadNoPriorDiags;
917 EvalInfo::EvaluationMode OldMode;
918
919 explicit FoldConstant(EvalInfo &Info, bool Enabled)
920 : Info(Info),
921 Enabled(Enabled),
922 HadNoPriorDiags(Info.EvalStatus.Diag &&
923 Info.EvalStatus.Diag->empty() &&
924 !Info.EvalStatus.HasSideEffects),
925 OldMode(Info.EvalMode) {
926 if (Enabled &&
927 (Info.EvalMode == EvalInfo::EM_ConstantExpression ||
928 Info.EvalMode == EvalInfo::EM_ConstantExpressionUnevaluated))
929 Info.EvalMode = EvalInfo::EM_ConstantFold;
930 }
931 void keepDiagnostics() { Enabled = false; }
932 ~FoldConstant() {
933 if (Enabled && HadNoPriorDiags && !Info.EvalStatus.Diag->empty() &&
934 !Info.EvalStatus.HasSideEffects)
935 Info.EvalStatus.Diag->clear();
936 Info.EvalMode = OldMode;
937 }
938 };
939
940 /// RAII object used to treat the current evaluation as the correct pointer
941 /// offset fold for the current EvalMode
942 struct FoldOffsetRAII {
943 EvalInfo &Info;
944 EvalInfo::EvaluationMode OldMode;
945 explicit FoldOffsetRAII(EvalInfo &Info)
946 : Info(Info), OldMode(Info.EvalMode) {
947 if (!Info.checkingPotentialConstantExpression())
948 Info.EvalMode = EvalInfo::EM_OffsetFold;
949 }
950
951 ~FoldOffsetRAII() { Info.EvalMode = OldMode; }
952 };
953
954 /// RAII object used to optionally suppress diagnostics and side-effects from
955 /// a speculative evaluation.
956 class SpeculativeEvaluationRAII {
957 /// Pair of EvalInfo, and a bit that stores whether or not we were
958 /// speculatively evaluating when we created this RAII.
959 llvm::PointerIntPair<EvalInfo *, 1, bool> InfoAndOldSpecEval;
960 Expr::EvalStatus Old;
961
962 void moveFromAndCancel(SpeculativeEvaluationRAII &&Other) {
963 InfoAndOldSpecEval = Other.InfoAndOldSpecEval;
964 Old = Other.Old;
965 Other.InfoAndOldSpecEval.setPointer(nullptr);
966 }
967
968 void maybeRestoreState() {
969 EvalInfo *Info = InfoAndOldSpecEval.getPointer();
970 if (!Info)
971 return;
972
973 Info->EvalStatus = Old;
974 Info->IsSpeculativelyEvaluating = InfoAndOldSpecEval.getInt();
975 }
976
977 public:
978 SpeculativeEvaluationRAII() = default;
979
980 SpeculativeEvaluationRAII(
981 EvalInfo &Info, SmallVectorImpl<PartialDiagnosticAt> *NewDiag = nullptr)
982 : InfoAndOldSpecEval(&Info, Info.IsSpeculativelyEvaluating),
983 Old(Info.EvalStatus) {
984 Info.EvalStatus.Diag = NewDiag;
985 Info.IsSpeculativelyEvaluating = true;
986 }
987
988 SpeculativeEvaluationRAII(const SpeculativeEvaluationRAII &Other) = delete;
989 SpeculativeEvaluationRAII(SpeculativeEvaluationRAII &&Other) {
990 moveFromAndCancel(std::move(Other));
991 }
992
993 SpeculativeEvaluationRAII &operator=(SpeculativeEvaluationRAII &&Other) {
994 maybeRestoreState();
995 moveFromAndCancel(std::move(Other));
996 return *this;
997 }
998
999 ~SpeculativeEvaluationRAII() { maybeRestoreState(); }
1000 };
1001
1002 /// RAII object wrapping a full-expression or block scope, and handling
1003 /// the ending of the lifetime of temporaries created within it.
1004 template<bool IsFullExpression>
1005 class ScopeRAII {
1006 EvalInfo &Info;
1007 unsigned OldStackSize;
1008 public:
1009 ScopeRAII(EvalInfo &Info)
1010 : Info(Info), OldStackSize(Info.CleanupStack.size()) {}
1011 ~ScopeRAII() {
1012 // Body moved to a static method to encourage the compiler to inline away
1013 // instances of this class.
1014 cleanup(Info, OldStackSize);
1015 }
1016 private:
1017 static void cleanup(EvalInfo &Info, unsigned OldStackSize) {
1018 unsigned NewEnd = OldStackSize;
1019 for (unsigned I = OldStackSize, N = Info.CleanupStack.size();
1020 I != N; ++I) {
1021 if (IsFullExpression && Info.CleanupStack[I].isLifetimeExtended()) {
1022 // Full-expression cleanup of a lifetime-extended temporary: nothing
1023 // to do, just move this cleanup to the right place in the stack.
1024 std::swap(Info.CleanupStack[I], Info.CleanupStack[NewEnd]);
1025 ++NewEnd;
1026 } else {
1027 // End the lifetime of the object.
1028 Info.CleanupStack[I].endLifetime();
1029 }
1030 }
1031 Info.CleanupStack.erase(Info.CleanupStack.begin() + NewEnd,
1032 Info.CleanupStack.end());
1033 }
1034 };
1035 typedef ScopeRAII<false> BlockScopeRAII;
1036 typedef ScopeRAII<true> FullExpressionRAII;
1037}
1038
1039bool SubobjectDesignator::checkSubobject(EvalInfo &Info, const Expr *E,
1040 CheckSubobjectKind CSK) {
1041 if (Invalid)
1042 return false;
1043 if (isOnePastTheEnd()) {
1044 Info.CCEDiag(E, diag::note_constexpr_past_end_subobject)
1045 << CSK;
1046 setInvalid();
1047 return false;
1048 }
1049 return true;
1050}
1051
1052void SubobjectDesignator::diagnosePointerArithmetic(EvalInfo &Info,
1053 const Expr *E, uint64_t N) {
1054 // If we're complaining, we must be able to statically determine the size of
1055 // the most derived array.
1056 if (MostDerivedPathLength == Entries.size() && MostDerivedIsArrayElement)
1057 Info.CCEDiag(E, diag::note_constexpr_array_index)
1058 << static_cast<int>(N) << /*array*/ 0
1059 << static_cast<unsigned>(getMostDerivedArraySize());
1060 else
1061 Info.CCEDiag(E, diag::note_constexpr_array_index)
1062 << static_cast<int>(N) << /*non-array*/ 1;
1063 setInvalid();
1064}
1065
1066CallStackFrame::CallStackFrame(EvalInfo &Info, SourceLocation CallLoc,
1067 const FunctionDecl *Callee, const LValue *This,
1068 APValue *Arguments)
1069 : Info(Info), Caller(Info.CurrentCall), Callee(Callee), This(This),
1070 Arguments(Arguments), CallLoc(CallLoc), Index(Info.NextCallIndex++) {
1071 Info.CurrentCall = this;
1072 ++Info.CallStackDepth;
1073}
1074
1075CallStackFrame::~CallStackFrame() {
1076 assert(Info.CurrentCall == this && "calls retired out of order")((Info.CurrentCall == this && "calls retired out of order"
) ? static_cast<void> (0) : __assert_fail ("Info.CurrentCall == this && \"calls retired out of order\""
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 1076, __PRETTY_FUNCTION__))
;
1077 --Info.CallStackDepth;
1078 Info.CurrentCall = Caller;
1079}
1080
1081APValue &CallStackFrame::createTemporary(const void *Key,
1082 bool IsLifetimeExtended) {
1083 APValue &Result = Temporaries[Key];
1084 assert(Result.isUninit() && "temporary created multiple times")((Result.isUninit() && "temporary created multiple times"
) ? static_cast<void> (0) : __assert_fail ("Result.isUninit() && \"temporary created multiple times\""
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 1084, __PRETTY_FUNCTION__))
;
1085 Info.CleanupStack.push_back(Cleanup(&Result, IsLifetimeExtended));
1086 return Result;
1087}
1088
1089static void describeCall(CallStackFrame *Frame, raw_ostream &Out);
1090
1091void EvalInfo::addCallStack(unsigned Limit) {
1092 // Determine which calls to skip, if any.
1093 unsigned ActiveCalls = CallStackDepth - 1;
1094 unsigned SkipStart = ActiveCalls, SkipEnd = SkipStart;
1095 if (Limit && Limit < ActiveCalls) {
1096 SkipStart = Limit / 2 + Limit % 2;
1097 SkipEnd = ActiveCalls - Limit / 2;
1098 }
1099
1100 // Walk the call stack and add the diagnostics.
1101 unsigned CallIdx = 0;
1102 for (CallStackFrame *Frame = CurrentCall; Frame != &BottomFrame;
1103 Frame = Frame->Caller, ++CallIdx) {
1104 // Skip this call?
1105 if (CallIdx >= SkipStart && CallIdx < SkipEnd) {
1106 if (CallIdx == SkipStart) {
1107 // Note that we're skipping calls.
1108 addDiag(Frame->CallLoc, diag::note_constexpr_calls_suppressed)
1109 << unsigned(ActiveCalls - Limit);
1110 }
1111 continue;
1112 }
1113
1114 // Use a different note for an inheriting constructor, because from the
1115 // user's perspective it's not really a function at all.
1116 if (auto *CD = dyn_cast_or_null<CXXConstructorDecl>(Frame->Callee)) {
1117 if (CD->isInheritingConstructor()) {
1118 addDiag(Frame->CallLoc, diag::note_constexpr_inherited_ctor_call_here)
1119 << CD->getParent();
1120 continue;
1121 }
1122 }
1123
1124 SmallVector<char, 128> Buffer;
1125 llvm::raw_svector_ostream Out(Buffer);
1126 describeCall(Frame, Out);
1127 addDiag(Frame->CallLoc, diag::note_constexpr_call_here) << Out.str();
1128 }
1129}
1130
1131namespace {
1132 struct ComplexValue {
1133 private:
1134 bool IsInt;
1135
1136 public:
1137 APSInt IntReal, IntImag;
1138 APFloat FloatReal, FloatImag;
1139
1140 ComplexValue() : FloatReal(APFloat::Bogus()), FloatImag(APFloat::Bogus()) {}
1141
1142 void makeComplexFloat() { IsInt = false; }
1143 bool isComplexFloat() const { return !IsInt; }
1144 APFloat &getComplexFloatReal() { return FloatReal; }
1145 APFloat &getComplexFloatImag() { return FloatImag; }
1146
1147 void makeComplexInt() { IsInt = true; }
1148 bool isComplexInt() const { return IsInt; }
1149 APSInt &getComplexIntReal() { return IntReal; }
1150 APSInt &getComplexIntImag() { return IntImag; }
1151
1152 void moveInto(APValue &v) const {
1153 if (isComplexFloat())
1154 v = APValue(FloatReal, FloatImag);
1155 else
1156 v = APValue(IntReal, IntImag);
1157 }
1158 void setFrom(const APValue &v) {
1159 assert(v.isComplexFloat() || v.isComplexInt())((v.isComplexFloat() || v.isComplexInt()) ? static_cast<void
> (0) : __assert_fail ("v.isComplexFloat() || v.isComplexInt()"
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 1159, __PRETTY_FUNCTION__))
;
1160 if (v.isComplexFloat()) {
1161 makeComplexFloat();
1162 FloatReal = v.getComplexFloatReal();
1163 FloatImag = v.getComplexFloatImag();
1164 } else {
1165 makeComplexInt();
1166 IntReal = v.getComplexIntReal();
1167 IntImag = v.getComplexIntImag();
1168 }
1169 }
1170 };
1171
1172 struct LValue {
1173 APValue::LValueBase Base;
1174 CharUnits Offset;
1175 unsigned InvalidBase : 1;
1176 unsigned CallIndex : 31;
1177 SubobjectDesignator Designator;
1178 bool IsNullPtr;
1179
1180 const APValue::LValueBase getLValueBase() const { return Base; }
1181 CharUnits &getLValueOffset() { return Offset; }
1182 const CharUnits &getLValueOffset() const { return Offset; }
1183 unsigned getLValueCallIndex() const { return CallIndex; }
1184 SubobjectDesignator &getLValueDesignator() { return Designator; }
1185 const SubobjectDesignator &getLValueDesignator() const { return Designator;}
1186 bool isNullPointer() const { return IsNullPtr;}
1187
1188 void moveInto(APValue &V) const {
1189 if (Designator.Invalid)
1190 V = APValue(Base, Offset, APValue::NoLValuePath(), CallIndex,
1191 IsNullPtr);
1192 else {
1193 assert(!InvalidBase && "APValues can't handle invalid LValue bases")((!InvalidBase && "APValues can't handle invalid LValue bases"
) ? static_cast<void> (0) : __assert_fail ("!InvalidBase && \"APValues can't handle invalid LValue bases\""
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 1193, __PRETTY_FUNCTION__))
;
1194 assert(!Designator.FirstEntryIsAnUnsizedArray &&((!Designator.FirstEntryIsAnUnsizedArray && "Unsized array with a valid base?"
) ? static_cast<void> (0) : __assert_fail ("!Designator.FirstEntryIsAnUnsizedArray && \"Unsized array with a valid base?\""
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 1195, __PRETTY_FUNCTION__))
1195 "Unsized array with a valid base?")((!Designator.FirstEntryIsAnUnsizedArray && "Unsized array with a valid base?"
) ? static_cast<void> (0) : __assert_fail ("!Designator.FirstEntryIsAnUnsizedArray && \"Unsized array with a valid base?\""
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 1195, __PRETTY_FUNCTION__))
;
1196 V = APValue(Base, Offset, Designator.Entries,
1197 Designator.IsOnePastTheEnd, CallIndex, IsNullPtr);
1198 }
1199 }
1200 void setFrom(ASTContext &Ctx, const APValue &V) {
1201 assert(V.isLValue() && "Setting LValue from a non-LValue?")((V.isLValue() && "Setting LValue from a non-LValue?"
) ? static_cast<void> (0) : __assert_fail ("V.isLValue() && \"Setting LValue from a non-LValue?\""
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 1201, __PRETTY_FUNCTION__))
;
1202 Base = V.getLValueBase();
1203 Offset = V.getLValueOffset();
1204 InvalidBase = false;
1205 CallIndex = V.getLValueCallIndex();
1206 Designator = SubobjectDesignator(Ctx, V);
1207 IsNullPtr = V.isNullPointer();
1208 }
1209
1210 void set(APValue::LValueBase B, unsigned I = 0, bool BInvalid = false,
1211 bool IsNullPtr_ = false, uint64_t Offset_ = 0) {
1212#ifndef NDEBUG
1213 // We only allow a few types of invalid bases. Enforce that here.
1214 if (BInvalid) {
1215 const auto *E = B.get<const Expr *>();
1216 assert((isa<MemberExpr>(E) || tryUnwrapAllocSizeCall(E)) &&(((isa<MemberExpr>(E) || tryUnwrapAllocSizeCall(E)) &&
"Unexpected type of invalid base") ? static_cast<void>
(0) : __assert_fail ("(isa<MemberExpr>(E) || tryUnwrapAllocSizeCall(E)) && \"Unexpected type of invalid base\""
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 1217, __PRETTY_FUNCTION__))
1217 "Unexpected type of invalid base")(((isa<MemberExpr>(E) || tryUnwrapAllocSizeCall(E)) &&
"Unexpected type of invalid base") ? static_cast<void>
(0) : __assert_fail ("(isa<MemberExpr>(E) || tryUnwrapAllocSizeCall(E)) && \"Unexpected type of invalid base\""
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 1217, __PRETTY_FUNCTION__))
;
1218 }
1219#endif
1220
1221 Base = B;
1222 Offset = CharUnits::fromQuantity(Offset_);
1223 InvalidBase = BInvalid;
1224 CallIndex = I;
1225 Designator = SubobjectDesignator(getType(B));
1226 IsNullPtr = IsNullPtr_;
1227 }
1228
1229 void setInvalid(APValue::LValueBase B, unsigned I = 0) {
1230 set(B, I, true);
1231 }
1232
1233 // Check that this LValue is not based on a null pointer. If it is, produce
1234 // a diagnostic and mark the designator as invalid.
1235 bool checkNullPointer(EvalInfo &Info, const Expr *E,
1236 CheckSubobjectKind CSK) {
1237 if (Designator.Invalid)
1238 return false;
1239 if (IsNullPtr) {
1240 Info.CCEDiag(E, diag::note_constexpr_null_subobject)
1241 << CSK;
1242 Designator.setInvalid();
1243 return false;
1244 }
1245 return true;
1246 }
1247
1248 // Check this LValue refers to an object. If not, set the designator to be
1249 // invalid and emit a diagnostic.
1250 bool checkSubobject(EvalInfo &Info, const Expr *E, CheckSubobjectKind CSK) {
1251 return (CSK == CSK_ArrayToPointer || checkNullPointer(Info, E, CSK)) &&
1252 Designator.checkSubobject(Info, E, CSK);
1253 }
1254
1255 void addDecl(EvalInfo &Info, const Expr *E,
1256 const Decl *D, bool Virtual = false) {
1257 if (checkSubobject(Info, E, isa<FieldDecl>(D) ? CSK_Field : CSK_Base))
1258 Designator.addDeclUnchecked(D, Virtual);
1259 }
1260 void addUnsizedArray(EvalInfo &Info, QualType ElemTy) {
1261 assert(Designator.Entries.empty() && getType(Base)->isPointerType())((Designator.Entries.empty() && getType(Base)->isPointerType
()) ? static_cast<void> (0) : __assert_fail ("Designator.Entries.empty() && getType(Base)->isPointerType()"
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 1261, __PRETTY_FUNCTION__))
;
1262 assert(isBaseAnAllocSizeCall(Base) &&((isBaseAnAllocSizeCall(Base) && "Only alloc_size bases can have unsized arrays"
) ? static_cast<void> (0) : __assert_fail ("isBaseAnAllocSizeCall(Base) && \"Only alloc_size bases can have unsized arrays\""
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 1263, __PRETTY_FUNCTION__))
1263 "Only alloc_size bases can have unsized arrays")((isBaseAnAllocSizeCall(Base) && "Only alloc_size bases can have unsized arrays"
) ? static_cast<void> (0) : __assert_fail ("isBaseAnAllocSizeCall(Base) && \"Only alloc_size bases can have unsized arrays\""
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 1263, __PRETTY_FUNCTION__))
;
1264 Designator.FirstEntryIsAnUnsizedArray = true;
1265 Designator.addUnsizedArrayUnchecked(ElemTy);
1266 }
1267 void addArray(EvalInfo &Info, const Expr *E, const ConstantArrayType *CAT) {
1268 if (checkSubobject(Info, E, CSK_ArrayToPointer))
1269 Designator.addArrayUnchecked(CAT);
1270 }
1271 void addComplex(EvalInfo &Info, const Expr *E, QualType EltTy, bool Imag) {
1272 if (checkSubobject(Info, E, Imag ? CSK_Imag : CSK_Real))
1273 Designator.addComplexUnchecked(EltTy, Imag);
1274 }
1275 void clearIsNullPointer() {
1276 IsNullPtr = false;
1277 }
1278 void adjustOffsetAndIndex(EvalInfo &Info, const Expr *E, uint64_t Index,
1279 CharUnits ElementSize) {
1280 // Compute the new offset in the appropriate width.
1281 Offset += Index * ElementSize;
1282 if (Index && checkNullPointer(Info, E, CSK_ArrayIndex))
1283 Designator.adjustIndex(Info, E, Index);
1284 if (Index)
1285 clearIsNullPointer();
1286 }
1287 void adjustOffset(CharUnits N) {
1288 Offset += N;
1289 if (N.getQuantity())
1290 clearIsNullPointer();
1291 }
1292 };
1293
1294 struct MemberPtr {
1295 MemberPtr() {}
1296 explicit MemberPtr(const ValueDecl *Decl) :
1297 DeclAndIsDerivedMember(Decl, false), Path() {}
1298
1299 /// The member or (direct or indirect) field referred to by this member
1300 /// pointer, or 0 if this is a null member pointer.
1301 const ValueDecl *getDecl() const {
1302 return DeclAndIsDerivedMember.getPointer();
1303 }
1304 /// Is this actually a member of some type derived from the relevant class?
1305 bool isDerivedMember() const {
1306 return DeclAndIsDerivedMember.getInt();
1307 }
1308 /// Get the class which the declaration actually lives in.
1309 const CXXRecordDecl *getContainingRecord() const {
1310 return cast<CXXRecordDecl>(
1311 DeclAndIsDerivedMember.getPointer()->getDeclContext());
1312 }
1313
1314 void moveInto(APValue &V) const {
1315 V = APValue(getDecl(), isDerivedMember(), Path);
1316 }
1317 void setFrom(const APValue &V) {
1318 assert(V.isMemberPointer())((V.isMemberPointer()) ? static_cast<void> (0) : __assert_fail
("V.isMemberPointer()", "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 1318, __PRETTY_FUNCTION__))
;
1319 DeclAndIsDerivedMember.setPointer(V.getMemberPointerDecl());
1320 DeclAndIsDerivedMember.setInt(V.isMemberPointerToDerivedMember());
1321 Path.clear();
1322 ArrayRef<const CXXRecordDecl*> P = V.getMemberPointerPath();
1323 Path.insert(Path.end(), P.begin(), P.end());
1324 }
1325
1326 /// DeclAndIsDerivedMember - The member declaration, and a flag indicating
1327 /// whether the member is a member of some class derived from the class type
1328 /// of the member pointer.
1329 llvm::PointerIntPair<const ValueDecl*, 1, bool> DeclAndIsDerivedMember;
1330 /// Path - The path of base/derived classes from the member declaration's
1331 /// class (exclusive) to the class type of the member pointer (inclusive).
1332 SmallVector<const CXXRecordDecl*, 4> Path;
1333
1334 /// Perform a cast towards the class of the Decl (either up or down the
1335 /// hierarchy).
1336 bool castBack(const CXXRecordDecl *Class) {
1337 assert(!Path.empty())((!Path.empty()) ? static_cast<void> (0) : __assert_fail
("!Path.empty()", "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 1337, __PRETTY_FUNCTION__))
;
1338 const CXXRecordDecl *Expected;
1339 if (Path.size() >= 2)
1340 Expected = Path[Path.size() - 2];
1341 else
1342 Expected = getContainingRecord();
1343 if (Expected->getCanonicalDecl() != Class->getCanonicalDecl()) {
1344 // C++11 [expr.static.cast]p12: In a conversion from (D::*) to (B::*),
1345 // if B does not contain the original member and is not a base or
1346 // derived class of the class containing the original member, the result
1347 // of the cast is undefined.
1348 // C++11 [conv.mem]p2 does not cover this case for a cast from (B::*) to
1349 // (D::*). We consider that to be a language defect.
1350 return false;
1351 }
1352 Path.pop_back();
1353 return true;
1354 }
1355 /// Perform a base-to-derived member pointer cast.
1356 bool castToDerived(const CXXRecordDecl *Derived) {
1357 if (!getDecl())
1358 return true;
1359 if (!isDerivedMember()) {
1360 Path.push_back(Derived);
1361 return true;
1362 }
1363 if (!castBack(Derived))
1364 return false;
1365 if (Path.empty())
1366 DeclAndIsDerivedMember.setInt(false);
1367 return true;
1368 }
1369 /// Perform a derived-to-base member pointer cast.
1370 bool castToBase(const CXXRecordDecl *Base) {
1371 if (!getDecl())
1372 return true;
1373 if (Path.empty())
1374 DeclAndIsDerivedMember.setInt(true);
1375 if (isDerivedMember()) {
1376 Path.push_back(Base);
1377 return true;
1378 }
1379 return castBack(Base);
1380 }
1381 };
1382
1383 /// Compare two member pointers, which are assumed to be of the same type.
1384 static bool operator==(const MemberPtr &LHS, const MemberPtr &RHS) {
1385 if (!LHS.getDecl() || !RHS.getDecl())
1386 return !LHS.getDecl() && !RHS.getDecl();
1387 if (LHS.getDecl()->getCanonicalDecl() != RHS.getDecl()->getCanonicalDecl())
1388 return false;
1389 return LHS.Path == RHS.Path;
1390 }
1391}
1392
1393static bool Evaluate(APValue &Result, EvalInfo &Info, const Expr *E);
1394static bool EvaluateInPlace(APValue &Result, EvalInfo &Info,
1395 const LValue &This, const Expr *E,
1396 bool AllowNonLiteralTypes = false);
1397static bool EvaluateLValue(const Expr *E, LValue &Result, EvalInfo &Info);
1398static bool EvaluatePointer(const Expr *E, LValue &Result, EvalInfo &Info);
1399static bool EvaluateMemberPointer(const Expr *E, MemberPtr &Result,
1400 EvalInfo &Info);
1401static bool EvaluateTemporary(const Expr *E, LValue &Result, EvalInfo &Info);
1402static bool EvaluateInteger(const Expr *E, APSInt &Result, EvalInfo &Info);
1403static bool EvaluateIntegerOrLValue(const Expr *E, APValue &Result,
1404 EvalInfo &Info);
1405static bool EvaluateFloat(const Expr *E, APFloat &Result, EvalInfo &Info);
1406static bool EvaluateComplex(const Expr *E, ComplexValue &Res, EvalInfo &Info);
1407static bool EvaluateAtomic(const Expr *E, APValue &Result, EvalInfo &Info);
1408static bool EvaluateAsRValue(EvalInfo &Info, const Expr *E, APValue &Result);
1409
1410//===----------------------------------------------------------------------===//
1411// Misc utilities
1412//===----------------------------------------------------------------------===//
1413
1414/// Produce a string describing the given constexpr call.
1415static void describeCall(CallStackFrame *Frame, raw_ostream &Out) {
1416 unsigned ArgIndex = 0;
1417 bool IsMemberCall = isa<CXXMethodDecl>(Frame->Callee) &&
1418 !isa<CXXConstructorDecl>(Frame->Callee) &&
1419 cast<CXXMethodDecl>(Frame->Callee)->isInstance();
1420
1421 if (!IsMemberCall)
1422 Out << *Frame->Callee << '(';
1423
1424 if (Frame->This && IsMemberCall) {
1425 APValue Val;
1426 Frame->This->moveInto(Val);
1427 Val.printPretty(Out, Frame->Info.Ctx,
1428 Frame->This->Designator.MostDerivedType);
1429 // FIXME: Add parens around Val if needed.
1430 Out << "->" << *Frame->Callee << '(';
1431 IsMemberCall = false;
1432 }
1433
1434 for (FunctionDecl::param_const_iterator I = Frame->Callee->param_begin(),
1435 E = Frame->Callee->param_end(); I != E; ++I, ++ArgIndex) {
1436 if (ArgIndex > (unsigned)IsMemberCall)
1437 Out << ", ";
1438
1439 const ParmVarDecl *Param = *I;
1440 const APValue &Arg = Frame->Arguments[ArgIndex];
1441 Arg.printPretty(Out, Frame->Info.Ctx, Param->getType());
1442
1443 if (ArgIndex == 0 && IsMemberCall)
1444 Out << "->" << *Frame->Callee << '(';
1445 }
1446
1447 Out << ')';
1448}
1449
1450/// Evaluate an expression to see if it had side-effects, and discard its
1451/// result.
1452/// \return \c true if the caller should keep evaluating.
1453static bool EvaluateIgnoredValue(EvalInfo &Info, const Expr *E) {
1454 APValue Scratch;
1455 if (!Evaluate(Scratch, Info, E))
1456 // We don't need the value, but we might have skipped a side effect here.
1457 return Info.noteSideEffect();
1458 return true;
1459}
1460
1461/// Sign- or zero-extend a value to 64 bits. If it's already 64 bits, just
1462/// return its existing value.
1463static int64_t getExtValue(const APSInt &Value) {
1464 return Value.isSigned() ? Value.getSExtValue()
1465 : static_cast<int64_t>(Value.getZExtValue());
1466}
1467
1468/// Should this call expression be treated as a string literal?
1469static bool IsStringLiteralCall(const CallExpr *E) {
1470 unsigned Builtin = E->getBuiltinCallee();
1471 return (Builtin == Builtin::BI__builtin___CFStringMakeConstantString ||
1472 Builtin == Builtin::BI__builtin___NSStringMakeConstantString);
1473}
1474
1475static bool IsGlobalLValue(APValue::LValueBase B) {
1476 // C++11 [expr.const]p3 An address constant expression is a prvalue core
1477 // constant expression of pointer type that evaluates to...
1478
1479 // ... a null pointer value, or a prvalue core constant expression of type
1480 // std::nullptr_t.
1481 if (!B) return true;
1482
1483 if (const ValueDecl *D = B.dyn_cast<const ValueDecl*>()) {
1484 // ... the address of an object with static storage duration,
1485 if (const VarDecl *VD = dyn_cast<VarDecl>(D))
1486 return VD->hasGlobalStorage();
1487 // ... the address of a function,
1488 return isa<FunctionDecl>(D);
1489 }
1490
1491 const Expr *E = B.get<const Expr*>();
1492 switch (E->getStmtClass()) {
1493 default:
1494 return false;
1495 case Expr::CompoundLiteralExprClass: {
1496 const CompoundLiteralExpr *CLE = cast<CompoundLiteralExpr>(E);
1497 return CLE->isFileScope() && CLE->isLValue();
1498 }
1499 case Expr::MaterializeTemporaryExprClass:
1500 // A materialized temporary might have been lifetime-extended to static
1501 // storage duration.
1502 return cast<MaterializeTemporaryExpr>(E)->getStorageDuration() == SD_Static;
1503 // A string literal has static storage duration.
1504 case Expr::StringLiteralClass:
1505 case Expr::PredefinedExprClass:
1506 case Expr::ObjCStringLiteralClass:
1507 case Expr::ObjCEncodeExprClass:
1508 case Expr::CXXTypeidExprClass:
1509 case Expr::CXXUuidofExprClass:
1510 return true;
1511 case Expr::CallExprClass:
1512 return IsStringLiteralCall(cast<CallExpr>(E));
1513 // For GCC compatibility, &&label has static storage duration.
1514 case Expr::AddrLabelExprClass:
1515 return true;
1516 // A Block literal expression may be used as the initialization value for
1517 // Block variables at global or local static scope.
1518 case Expr::BlockExprClass:
1519 return !cast<BlockExpr>(E)->getBlockDecl()->hasCaptures();
1520 case Expr::ImplicitValueInitExprClass:
1521 // FIXME:
1522 // We can never form an lvalue with an implicit value initialization as its
1523 // base through expression evaluation, so these only appear in one case: the
1524 // implicit variable declaration we invent when checking whether a constexpr
1525 // constructor can produce a constant expression. We must assume that such
1526 // an expression might be a global lvalue.
1527 return true;
1528 }
1529}
1530
1531static void NoteLValueLocation(EvalInfo &Info, APValue::LValueBase Base) {
1532 assert(Base && "no location for a null lvalue")((Base && "no location for a null lvalue") ? static_cast
<void> (0) : __assert_fail ("Base && \"no location for a null lvalue\""
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 1532, __PRETTY_FUNCTION__))
;
1533 const ValueDecl *VD = Base.dyn_cast<const ValueDecl*>();
1534 if (VD)
1535 Info.Note(VD->getLocation(), diag::note_declared_at);
1536 else
1537 Info.Note(Base.get<const Expr*>()->getExprLoc(),
1538 diag::note_constexpr_temporary_here);
1539}
1540
1541/// Check that this reference or pointer core constant expression is a valid
1542/// value for an address or reference constant expression. Return true if we
1543/// can fold this expression, whether or not it's a constant expression.
1544static bool CheckLValueConstantExpression(EvalInfo &Info, SourceLocation Loc,
1545 QualType Type, const LValue &LVal) {
1546 bool IsReferenceType = Type->isReferenceType();
1547
1548 APValue::LValueBase Base = LVal.getLValueBase();
1549 const SubobjectDesignator &Designator = LVal.getLValueDesignator();
1550
1551 // Check that the object is a global. Note that the fake 'this' object we
1552 // manufacture when checking potential constant expressions is conservatively
1553 // assumed to be global here.
1554 if (!IsGlobalLValue(Base)) {
1555 if (Info.getLangOpts().CPlusPlus11) {
1556 const ValueDecl *VD = Base.dyn_cast<const ValueDecl*>();
1557 Info.FFDiag(Loc, diag::note_constexpr_non_global, 1)
1558 << IsReferenceType << !Designator.Entries.empty()
1559 << !!VD << VD;
1560 NoteLValueLocation(Info, Base);
1561 } else {
1562 Info.FFDiag(Loc);
1563 }
1564 // Don't allow references to temporaries to escape.
1565 return false;
1566 }
1567 assert((Info.checkingPotentialConstantExpression() ||(((Info.checkingPotentialConstantExpression() || LVal.getLValueCallIndex
() == 0) && "have call index for global lvalue") ? static_cast
<void> (0) : __assert_fail ("(Info.checkingPotentialConstantExpression() || LVal.getLValueCallIndex() == 0) && \"have call index for global lvalue\""
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 1569, __PRETTY_FUNCTION__))
1568 LVal.getLValueCallIndex() == 0) &&(((Info.checkingPotentialConstantExpression() || LVal.getLValueCallIndex
() == 0) && "have call index for global lvalue") ? static_cast
<void> (0) : __assert_fail ("(Info.checkingPotentialConstantExpression() || LVal.getLValueCallIndex() == 0) && \"have call index for global lvalue\""
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 1569, __PRETTY_FUNCTION__))
1569 "have call index for global lvalue")(((Info.checkingPotentialConstantExpression() || LVal.getLValueCallIndex
() == 0) && "have call index for global lvalue") ? static_cast
<void> (0) : __assert_fail ("(Info.checkingPotentialConstantExpression() || LVal.getLValueCallIndex() == 0) && \"have call index for global lvalue\""
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 1569, __PRETTY_FUNCTION__))
;
1570
1571 if (const ValueDecl *VD = Base.dyn_cast<const ValueDecl*>()) {
1572 if (const VarDecl *Var = dyn_cast<const VarDecl>(VD)) {
1573 // Check if this is a thread-local variable.
1574 if (Var->getTLSKind())
1575 return false;
1576
1577 // A dllimport variable never acts like a constant.
1578 if (Var->hasAttr<DLLImportAttr>())
1579 return false;
1580 }
1581 if (const auto *FD = dyn_cast<const FunctionDecl>(VD)) {
1582 // __declspec(dllimport) must be handled very carefully:
1583 // We must never initialize an expression with the thunk in C++.
1584 // Doing otherwise would allow the same id-expression to yield
1585 // different addresses for the same function in different translation
1586 // units. However, this means that we must dynamically initialize the
1587 // expression with the contents of the import address table at runtime.
1588 //
1589 // The C language has no notion of ODR; furthermore, it has no notion of
1590 // dynamic initialization. This means that we are permitted to
1591 // perform initialization with the address of the thunk.
1592 if (Info.getLangOpts().CPlusPlus && FD->hasAttr<DLLImportAttr>())
1593 return false;
1594 }
1595 }
1596
1597 // Allow address constant expressions to be past-the-end pointers. This is
1598 // an extension: the standard requires them to point to an object.
1599 if (!IsReferenceType)
1600 return true;
1601
1602 // A reference constant expression must refer to an object.
1603 if (!Base) {
1604 // FIXME: diagnostic
1605 Info.CCEDiag(Loc);
1606 return true;
1607 }
1608
1609 // Does this refer one past the end of some object?
1610 if (!Designator.Invalid && Designator.isOnePastTheEnd()) {
1611 const ValueDecl *VD = Base.dyn_cast<const ValueDecl*>();
1612 Info.FFDiag(Loc, diag::note_constexpr_past_end, 1)
1613 << !Designator.Entries.empty() << !!VD << VD;
1614 NoteLValueLocation(Info, Base);
1615 }
1616
1617 return true;
1618}
1619
1620/// Check that this core constant expression is of literal type, and if not,
1621/// produce an appropriate diagnostic.
1622static bool CheckLiteralType(EvalInfo &Info, const Expr *E,
1623 const LValue *This = nullptr) {
1624 if (!E->isRValue() || E->getType()->isLiteralType(Info.Ctx))
1625 return true;
1626
1627 // C++1y: A constant initializer for an object o [...] may also invoke
1628 // constexpr constructors for o and its subobjects even if those objects
1629 // are of non-literal class types.
1630 if (Info.getLangOpts().CPlusPlus14 && This &&
1631 Info.EvaluatingDecl == This->getLValueBase())
1632 return true;
1633
1634 // Prvalue constant expressions must be of literal types.
1635 if (Info.getLangOpts().CPlusPlus11)
1636 Info.FFDiag(E, diag::note_constexpr_nonliteral)
1637 << E->getType();
1638 else
1639 Info.FFDiag(E, diag::note_invalid_subexpr_in_const_expr);
1640 return false;
1641}
1642
1643/// Check that this core constant expression value is a valid value for a
1644/// constant expression. If not, report an appropriate diagnostic. Does not
1645/// check that the expression is of literal type.
1646static bool CheckConstantExpression(EvalInfo &Info, SourceLocation DiagLoc,
1647 QualType Type, const APValue &Value) {
1648 if (Value.isUninit()) {
1649 Info.FFDiag(DiagLoc, diag::note_constexpr_uninitialized)
1650 << true << Type;
1651 return false;
1652 }
1653
1654 // We allow _Atomic(T) to be initialized from anything that T can be
1655 // initialized from.
1656 if (const AtomicType *AT = Type->getAs<AtomicType>())
1657 Type = AT->getValueType();
1658
1659 // Core issue 1454: For a literal constant expression of array or class type,
1660 // each subobject of its value shall have been initialized by a constant
1661 // expression.
1662 if (Value.isArray()) {
1663 QualType EltTy = Type->castAsArrayTypeUnsafe()->getElementType();
1664 for (unsigned I = 0, N = Value.getArrayInitializedElts(); I != N; ++I) {
1665 if (!CheckConstantExpression(Info, DiagLoc, EltTy,
1666 Value.getArrayInitializedElt(I)))
1667 return false;
1668 }
1669 if (!Value.hasArrayFiller())
1670 return true;
1671 return CheckConstantExpression(Info, DiagLoc, EltTy,
1672 Value.getArrayFiller());
1673 }
1674 if (Value.isUnion() && Value.getUnionField()) {
1675 return CheckConstantExpression(Info, DiagLoc,
1676 Value.getUnionField()->getType(),
1677 Value.getUnionValue());
1678 }
1679 if (Value.isStruct()) {
1680 RecordDecl *RD = Type->castAs<RecordType>()->getDecl();
1681 if (const CXXRecordDecl *CD = dyn_cast<CXXRecordDecl>(RD)) {
1682 unsigned BaseIndex = 0;
1683 for (CXXRecordDecl::base_class_const_iterator I = CD->bases_begin(),
1684 End = CD->bases_end(); I != End; ++I, ++BaseIndex) {
1685 if (!CheckConstantExpression(Info, DiagLoc, I->getType(),
1686 Value.getStructBase(BaseIndex)))
1687 return false;
1688 }
1689 }
1690 for (const auto *I : RD->fields()) {
1691 if (!CheckConstantExpression(Info, DiagLoc, I->getType(),
1692 Value.getStructField(I->getFieldIndex())))
1693 return false;
1694 }
1695 }
1696
1697 if (Value.isLValue()) {
1698 LValue LVal;
1699 LVal.setFrom(Info.Ctx, Value);
1700 return CheckLValueConstantExpression(Info, DiagLoc, Type, LVal);
1701 }
1702
1703 // Everything else is fine.
1704 return true;
1705}
1706
1707static const ValueDecl *GetLValueBaseDecl(const LValue &LVal) {
1708 return LVal.Base.dyn_cast<const ValueDecl*>();
1709}
1710
1711static bool IsLiteralLValue(const LValue &Value) {
1712 if (Value.CallIndex)
1713 return false;
1714 const Expr *E = Value.Base.dyn_cast<const Expr*>();
1715 return E && !isa<MaterializeTemporaryExpr>(E);
1716}
1717
1718static bool IsWeakLValue(const LValue &Value) {
1719 const ValueDecl *Decl = GetLValueBaseDecl(Value);
1720 return Decl && Decl->isWeak();
1721}
1722
1723static bool isZeroSized(const LValue &Value) {
1724 const ValueDecl *Decl = GetLValueBaseDecl(Value);
1725 if (Decl && isa<VarDecl>(Decl)) {
1726 QualType Ty = Decl->getType();
1727 if (Ty->isArrayType())
1728 return Ty->isIncompleteType() ||
1729 Decl->getASTContext().getTypeSize(Ty) == 0;
1730 }
1731 return false;
1732}
1733
1734static bool EvalPointerValueAsBool(const APValue &Value, bool &Result) {
1735 // A null base expression indicates a null pointer. These are always
1736 // evaluatable, and they are false unless the offset is zero.
1737 if (!Value.getLValueBase()) {
1738 Result = !Value.getLValueOffset().isZero();
1739 return true;
1740 }
1741
1742 // We have a non-null base. These are generally known to be true, but if it's
1743 // a weak declaration it can be null at runtime.
1744 Result = true;
1745 const ValueDecl *Decl = Value.getLValueBase().dyn_cast<const ValueDecl*>();
1746 return !Decl || !Decl->isWeak();
1747}
1748
1749static bool HandleConversionToBool(const APValue &Val, bool &Result) {
1750 switch (Val.getKind()) {
1751 case APValue::Uninitialized:
1752 return false;
1753 case APValue::Int:
1754 Result = Val.getInt().getBoolValue();
1755 return true;
1756 case APValue::Float:
1757 Result = !Val.getFloat().isZero();
1758 return true;
1759 case APValue::ComplexInt:
1760 Result = Val.getComplexIntReal().getBoolValue() ||
1761 Val.getComplexIntImag().getBoolValue();
1762 return true;
1763 case APValue::ComplexFloat:
1764 Result = !Val.getComplexFloatReal().isZero() ||
1765 !Val.getComplexFloatImag().isZero();
1766 return true;
1767 case APValue::LValue:
1768 return EvalPointerValueAsBool(Val, Result);
1769 case APValue::MemberPointer:
1770 Result = Val.getMemberPointerDecl();
1771 return true;
1772 case APValue::Vector:
1773 case APValue::Array:
1774 case APValue::Struct:
1775 case APValue::Union:
1776 case APValue::AddrLabelDiff:
1777 return false;
1778 }
1779
1780 llvm_unreachable("unknown APValue kind")::llvm::llvm_unreachable_internal("unknown APValue kind", "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 1780)
;
1781}
1782
1783static bool EvaluateAsBooleanCondition(const Expr *E, bool &Result,
1784 EvalInfo &Info) {
1785 assert(E->isRValue() && "missing lvalue-to-rvalue conv in bool condition")((E->isRValue() && "missing lvalue-to-rvalue conv in bool condition"
) ? static_cast<void> (0) : __assert_fail ("E->isRValue() && \"missing lvalue-to-rvalue conv in bool condition\""
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 1785, __PRETTY_FUNCTION__))
;
1786 APValue Val;
1787 if (!Evaluate(Val, Info, E))
1788 return false;
1789 return HandleConversionToBool(Val, Result);
1790}
1791
1792template<typename T>
1793static bool HandleOverflow(EvalInfo &Info, const Expr *E,
1794 const T &SrcValue, QualType DestType) {
1795 Info.CCEDiag(E, diag::note_constexpr_overflow)
1796 << SrcValue << DestType;
1797 return Info.noteUndefinedBehavior();
1798}
1799
1800static bool HandleFloatToIntCast(EvalInfo &Info, const Expr *E,
1801 QualType SrcType, const APFloat &Value,
1802 QualType DestType, APSInt &Result) {
1803 unsigned DestWidth = Info.Ctx.getIntWidth(DestType);
1804 // Determine whether we are converting to unsigned or signed.
1805 bool DestSigned = DestType->isSignedIntegerOrEnumerationType();
1806
1807 Result = APSInt(DestWidth, !DestSigned);
1808 bool ignored;
1809 if (Value.convertToInteger(Result, llvm::APFloat::rmTowardZero, &ignored)
1810 & APFloat::opInvalidOp)
1811 return HandleOverflow(Info, E, Value, DestType);
1812 return true;
1813}
1814
1815static bool HandleFloatToFloatCast(EvalInfo &Info, const Expr *E,
1816 QualType SrcType, QualType DestType,
1817 APFloat &Result) {
1818 APFloat Value = Result;
1819 bool ignored;
1820 if (Result.convert(Info.Ctx.getFloatTypeSemantics(DestType),
1821 APFloat::rmNearestTiesToEven, &ignored)
1822 & APFloat::opOverflow)
1823 return HandleOverflow(Info, E, Value, DestType);
1824 return true;
1825}
1826
1827static APSInt HandleIntToIntCast(EvalInfo &Info, const Expr *E,
1828 QualType DestType, QualType SrcType,
1829 const APSInt &Value) {
1830 unsigned DestWidth = Info.Ctx.getIntWidth(DestType);
1831 APSInt Result = Value;
1832 // Figure out if this is a truncate, extend or noop cast.
1833 // If the input is signed, do a sign extend, noop, or truncate.
1834 Result = Result.extOrTrunc(DestWidth);
1835 Result.setIsUnsigned(DestType->isUnsignedIntegerOrEnumerationType());
1836 return Result;
1837}
1838
1839static bool HandleIntToFloatCast(EvalInfo &Info, const Expr *E,
1840 QualType SrcType, const APSInt &Value,
1841 QualType DestType, APFloat &Result) {
1842 Result = APFloat(Info.Ctx.getFloatTypeSemantics(DestType), 1);
1843 if (Result.convertFromAPInt(Value, Value.isSigned(),
1844 APFloat::rmNearestTiesToEven)
1845 & APFloat::opOverflow)
1846 return HandleOverflow(Info, E, Value, DestType);
1847 return true;
1848}
1849
1850static bool truncateBitfieldValue(EvalInfo &Info, const Expr *E,
1851 APValue &Value, const FieldDecl *FD) {
1852 assert(FD->isBitField() && "truncateBitfieldValue on non-bitfield")((FD->isBitField() && "truncateBitfieldValue on non-bitfield"
) ? static_cast<void> (0) : __assert_fail ("FD->isBitField() && \"truncateBitfieldValue on non-bitfield\""
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 1852, __PRETTY_FUNCTION__))
;
1853
1854 if (!Value.isInt()) {
1855 // Trying to store a pointer-cast-to-integer into a bitfield.
1856 // FIXME: In this case, we should provide the diagnostic for casting
1857 // a pointer to an integer.
1858 assert(Value.isLValue() && "integral value neither int nor lvalue?")((Value.isLValue() && "integral value neither int nor lvalue?"
) ? static_cast<void> (0) : __assert_fail ("Value.isLValue() && \"integral value neither int nor lvalue?\""
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 1858, __PRETTY_FUNCTION__))
;
1859 Info.FFDiag(E);
1860 return false;
1861 }
1862
1863 APSInt &Int = Value.getInt();
1864 unsigned OldBitWidth = Int.getBitWidth();
1865 unsigned NewBitWidth = FD->getBitWidthValue(Info.Ctx);
1866 if (NewBitWidth < OldBitWidth)
1867 Int = Int.trunc(NewBitWidth).extend(OldBitWidth);
1868 return true;
1869}
1870
1871static bool EvalAndBitcastToAPInt(EvalInfo &Info, const Expr *E,
1872 llvm::APInt &Res) {
1873 APValue SVal;
1874 if (!Evaluate(SVal, Info, E))
1875 return false;
1876 if (SVal.isInt()) {
1877 Res = SVal.getInt();
1878 return true;
1879 }
1880 if (SVal.isFloat()) {
1881 Res = SVal.getFloat().bitcastToAPInt();
1882 return true;
1883 }
1884 if (SVal.isVector()) {
1885 QualType VecTy = E->getType();
1886 unsigned VecSize = Info.Ctx.getTypeSize(VecTy);
1887 QualType EltTy = VecTy->castAs<VectorType>()->getElementType();
1888 unsigned EltSize = Info.Ctx.getTypeSize(EltTy);
1889 bool BigEndian = Info.Ctx.getTargetInfo().isBigEndian();
1890 Res = llvm::APInt::getNullValue(VecSize);
1891 for (unsigned i = 0; i < SVal.getVectorLength(); i++) {
1892 APValue &Elt = SVal.getVectorElt(i);
1893 llvm::APInt EltAsInt;
1894 if (Elt.isInt()) {
1895 EltAsInt = Elt.getInt();
1896 } else if (Elt.isFloat()) {
1897 EltAsInt = Elt.getFloat().bitcastToAPInt();
1898 } else {
1899 // Don't try to handle vectors of anything other than int or float
1900 // (not sure if it's possible to hit this case).
1901 Info.FFDiag(E, diag::note_invalid_subexpr_in_const_expr);
1902 return false;
1903 }
1904 unsigned BaseEltSize = EltAsInt.getBitWidth();
1905 if (BigEndian)
1906 Res |= EltAsInt.zextOrTrunc(VecSize).rotr(i*EltSize+BaseEltSize);
1907 else
1908 Res |= EltAsInt.zextOrTrunc(VecSize).rotl(i*EltSize);
1909 }
1910 return true;
1911 }
1912 // Give up if the input isn't an int, float, or vector. For example, we
1913 // reject "(v4i16)(intptr_t)&a".
1914 Info.FFDiag(E, diag::note_invalid_subexpr_in_const_expr);
1915 return false;
1916}
1917
1918/// Perform the given integer operation, which is known to need at most BitWidth
1919/// bits, and check for overflow in the original type (if that type was not an
1920/// unsigned type).
1921template<typename Operation>
1922static bool CheckedIntArithmetic(EvalInfo &Info, const Expr *E,
1923 const APSInt &LHS, const APSInt &RHS,
1924 unsigned BitWidth, Operation Op,
1925 APSInt &Result) {
1926 if (LHS.isUnsigned()) {
1927 Result = Op(LHS, RHS);
1928 return true;
1929 }
1930
1931 APSInt Value(Op(LHS.extend(BitWidth), RHS.extend(BitWidth)), false);
1932 Result = Value.trunc(LHS.getBitWidth());
1933 if (Result.extend(BitWidth) != Value) {
1934 if (Info.checkingForOverflow())
1935 Info.Ctx.getDiagnostics().Report(E->getExprLoc(),
1936 diag::warn_integer_constant_overflow)
1937 << Result.toString(10) << E->getType();
1938 else
1939 return HandleOverflow(Info, E, Value, E->getType());
1940 }
1941 return true;
1942}
1943
1944/// Perform the given binary integer operation.
1945static bool handleIntIntBinOp(EvalInfo &Info, const Expr *E, const APSInt &LHS,
1946 BinaryOperatorKind Opcode, APSInt RHS,
1947 APSInt &Result) {
1948 switch (Opcode) {
1949 default:
1950 Info.FFDiag(E);
1951 return false;
1952 case BO_Mul:
1953 return CheckedIntArithmetic(Info, E, LHS, RHS, LHS.getBitWidth() * 2,
1954 std::multiplies<APSInt>(), Result);
1955 case BO_Add:
1956 return CheckedIntArithmetic(Info, E, LHS, RHS, LHS.getBitWidth() + 1,
1957 std::plus<APSInt>(), Result);
1958 case BO_Sub:
1959 return CheckedIntArithmetic(Info, E, LHS, RHS, LHS.getBitWidth() + 1,
1960 std::minus<APSInt>(), Result);
1961 case BO_And: Result = LHS & RHS; return true;
1962 case BO_Xor: Result = LHS ^ RHS; return true;
1963 case BO_Or: Result = LHS | RHS; return true;
1964 case BO_Div:
1965 case BO_Rem:
1966 if (RHS == 0) {
1967 Info.FFDiag(E, diag::note_expr_divide_by_zero);
1968 return false;
1969 }
1970 Result = (Opcode == BO_Rem ? LHS % RHS : LHS / RHS);
1971 // Check for overflow case: INT_MIN / -1 or INT_MIN % -1. APSInt supports
1972 // this operation and gives the two's complement result.
1973 if (RHS.isNegative() && RHS.isAllOnesValue() &&
1974 LHS.isSigned() && LHS.isMinSignedValue())
1975 return HandleOverflow(Info, E, -LHS.extend(LHS.getBitWidth() + 1),
1976 E->getType());
1977 return true;
1978 case BO_Shl: {
1979 if (Info.getLangOpts().OpenCL)
1980 // OpenCL 6.3j: shift values are effectively % word size of LHS.
1981 RHS &= APSInt(llvm::APInt(RHS.getBitWidth(),
1982 static_cast<uint64_t>(LHS.getBitWidth() - 1)),
1983 RHS.isUnsigned());
1984 else if (RHS.isSigned() && RHS.isNegative()) {
1985 // During constant-folding, a negative shift is an opposite shift. Such
1986 // a shift is not a constant expression.
1987 Info.CCEDiag(E, diag::note_constexpr_negative_shift) << RHS;
1988 RHS = -RHS;
1989 goto shift_right;
1990 }
1991 shift_left:
1992 // C++11 [expr.shift]p1: Shift width must be less than the bit width of
1993 // the shifted type.
1994 unsigned SA = (unsigned) RHS.getLimitedValue(LHS.getBitWidth()-1);
1995 if (SA != RHS) {
1996 Info.CCEDiag(E, diag::note_constexpr_large_shift)
1997 << RHS << E->getType() << LHS.getBitWidth();
1998 } else if (LHS.isSigned()) {
1999 // C++11 [expr.shift]p2: A signed left shift must have a non-negative
2000 // operand, and must not overflow the corresponding unsigned type.
2001 if (LHS.isNegative())
2002 Info.CCEDiag(E, diag::note_constexpr_lshift_of_negative) << LHS;
2003 else if (LHS.countLeadingZeros() < SA)
2004 Info.CCEDiag(E, diag::note_constexpr_lshift_discards);
2005 }
2006 Result = LHS << SA;
2007 return true;
2008 }
2009 case BO_Shr: {
2010 if (Info.getLangOpts().OpenCL)
2011 // OpenCL 6.3j: shift values are effectively % word size of LHS.
2012 RHS &= APSInt(llvm::APInt(RHS.getBitWidth(),
2013 static_cast<uint64_t>(LHS.getBitWidth() - 1)),
2014 RHS.isUnsigned());
2015 else if (RHS.isSigned() && RHS.isNegative()) {
2016 // During constant-folding, a negative shift is an opposite shift. Such a
2017 // shift is not a constant expression.
2018 Info.CCEDiag(E, diag::note_constexpr_negative_shift) << RHS;
2019 RHS = -RHS;
2020 goto shift_left;
2021 }
2022 shift_right:
2023 // C++11 [expr.shift]p1: Shift width must be less than the bit width of the
2024 // shifted type.
2025 unsigned SA = (unsigned) RHS.getLimitedValue(LHS.getBitWidth()-1);
2026 if (SA != RHS)
2027 Info.CCEDiag(E, diag::note_constexpr_large_shift)
2028 << RHS << E->getType() << LHS.getBitWidth();
2029 Result = LHS >> SA;
2030 return true;
2031 }
2032
2033 case BO_LT: Result = LHS < RHS; return true;
2034 case BO_GT: Result = LHS > RHS; return true;
2035 case BO_LE: Result = LHS <= RHS; return true;
2036 case BO_GE: Result = LHS >= RHS; return true;
2037 case BO_EQ: Result = LHS == RHS; return true;
2038 case BO_NE: Result = LHS != RHS; return true;
2039 }
2040}
2041
2042/// Perform the given binary floating-point operation, in-place, on LHS.
2043static bool handleFloatFloatBinOp(EvalInfo &Info, const Expr *E,
2044 APFloat &LHS, BinaryOperatorKind Opcode,
2045 const APFloat &RHS) {
2046 switch (Opcode) {
2047 default:
2048 Info.FFDiag(E);
2049 return false;
2050 case BO_Mul:
2051 LHS.multiply(RHS, APFloat::rmNearestTiesToEven);
2052 break;
2053 case BO_Add:
2054 LHS.add(RHS, APFloat::rmNearestTiesToEven);
2055 break;
2056 case BO_Sub:
2057 LHS.subtract(RHS, APFloat::rmNearestTiesToEven);
2058 break;
2059 case BO_Div:
2060 LHS.divide(RHS, APFloat::rmNearestTiesToEven);
2061 break;
2062 }
2063
2064 if (LHS.isInfinity() || LHS.isNaN()) {
2065 Info.CCEDiag(E, diag::note_constexpr_float_arithmetic) << LHS.isNaN();
2066 return Info.noteUndefinedBehavior();
2067 }
2068 return true;
2069}
2070
2071/// Cast an lvalue referring to a base subobject to a derived class, by
2072/// truncating the lvalue's path to the given length.
2073static bool CastToDerivedClass(EvalInfo &Info, const Expr *E, LValue &Result,
2074 const RecordDecl *TruncatedType,
2075 unsigned TruncatedElements) {
2076 SubobjectDesignator &D = Result.Designator;
2077
2078 // Check we actually point to a derived class object.
2079 if (TruncatedElements == D.Entries.size())
2080 return true;
2081 assert(TruncatedElements >= D.MostDerivedPathLength &&((TruncatedElements >= D.MostDerivedPathLength && "not casting to a derived class"
) ? static_cast<void> (0) : __assert_fail ("TruncatedElements >= D.MostDerivedPathLength && \"not casting to a derived class\""
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 2082, __PRETTY_FUNCTION__))
2082 "not casting to a derived class")((TruncatedElements >= D.MostDerivedPathLength && "not casting to a derived class"
) ? static_cast<void> (0) : __assert_fail ("TruncatedElements >= D.MostDerivedPathLength && \"not casting to a derived class\""
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 2082, __PRETTY_FUNCTION__))
;
2083 if (!Result.checkSubobject(Info, E, CSK_Derived))
2084 return false;
2085
2086 // Truncate the path to the subobject, and remove any derived-to-base offsets.
2087 const RecordDecl *RD = TruncatedType;
2088 for (unsigned I = TruncatedElements, N = D.Entries.size(); I != N; ++I) {
2089 if (RD->isInvalidDecl()) return false;
2090 const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(RD);
2091 const CXXRecordDecl *Base = getAsBaseClass(D.Entries[I]);
2092 if (isVirtualBaseClass(D.Entries[I]))
2093 Result.Offset -= Layout.getVBaseClassOffset(Base);
2094 else
2095 Result.Offset -= Layout.getBaseClassOffset(Base);
2096 RD = Base;
2097 }
2098 D.Entries.resize(TruncatedElements);
2099 return true;
2100}
2101
2102static bool HandleLValueDirectBase(EvalInfo &Info, const Expr *E, LValue &Obj,
2103 const CXXRecordDecl *Derived,
2104 const CXXRecordDecl *Base,
2105 const ASTRecordLayout *RL = nullptr) {
2106 if (!RL) {
2107 if (Derived->isInvalidDecl()) return false;
2108 RL = &Info.Ctx.getASTRecordLayout(Derived);
2109 }
2110
2111 Obj.getLValueOffset() += RL->getBaseClassOffset(Base);
2112 Obj.addDecl(Info, E, Base, /*Virtual*/ false);
2113 return true;
2114}
2115
2116static bool HandleLValueBase(EvalInfo &Info, const Expr *E, LValue &Obj,
2117 const CXXRecordDecl *DerivedDecl,
2118 const CXXBaseSpecifier *Base) {
2119 const CXXRecordDecl *BaseDecl = Base->getType()->getAsCXXRecordDecl();
2120
2121 if (!Base->isVirtual())
2122 return HandleLValueDirectBase(Info, E, Obj, DerivedDecl, BaseDecl);
2123
2124 SubobjectDesignator &D = Obj.Designator;
2125 if (D.Invalid)
2126 return false;
2127
2128 // Extract most-derived object and corresponding type.
2129 DerivedDecl = D.MostDerivedType->getAsCXXRecordDecl();
2130 if (!CastToDerivedClass(Info, E, Obj, DerivedDecl, D.MostDerivedPathLength))
2131 return false;
2132
2133 // Find the virtual base class.
2134 if (DerivedDecl->isInvalidDecl()) return false;
2135 const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(DerivedDecl);
2136 Obj.getLValueOffset() += Layout.getVBaseClassOffset(BaseDecl);
2137 Obj.addDecl(Info, E, BaseDecl, /*Virtual*/ true);
2138 return true;
2139}
2140
2141static bool HandleLValueBasePath(EvalInfo &Info, const CastExpr *E,
2142 QualType Type, LValue &Result) {
2143 for (CastExpr::path_const_iterator PathI = E->path_begin(),
2144 PathE = E->path_end();
2145 PathI != PathE; ++PathI) {
2146 if (!HandleLValueBase(Info, E, Result, Type->getAsCXXRecordDecl(),
2147 *PathI))
2148 return false;
2149 Type = (*PathI)->getType();
2150 }
2151 return true;
2152}
2153
2154/// Update LVal to refer to the given field, which must be a member of the type
2155/// currently described by LVal.
2156static bool HandleLValueMember(EvalInfo &Info, const Expr *E, LValue &LVal,
2157 const FieldDecl *FD,
2158 const ASTRecordLayout *RL = nullptr) {
2159 if (!RL) {
2160 if (FD->getParent()->isInvalidDecl()) return false;
2161 RL = &Info.Ctx.getASTRecordLayout(FD->getParent());
2162 }
2163
2164 unsigned I = FD->getFieldIndex();
2165 LVal.adjustOffset(Info.Ctx.toCharUnitsFromBits(RL->getFieldOffset(I)));
2166 LVal.addDecl(Info, E, FD);
2167 return true;
2168}
2169
2170/// Update LVal to refer to the given indirect field.
2171static bool HandleLValueIndirectMember(EvalInfo &Info, const Expr *E,
2172 LValue &LVal,
2173 const IndirectFieldDecl *IFD) {
2174 for (const auto *C : IFD->chain())
2175 if (!HandleLValueMember(Info, E, LVal, cast<FieldDecl>(C)))
2176 return false;
2177 return true;
2178}
2179
2180/// Get the size of the given type in char units.
2181static bool HandleSizeof(EvalInfo &Info, SourceLocation Loc,
2182 QualType Type, CharUnits &Size) {
2183 // sizeof(void), __alignof__(void), sizeof(function) = 1 as a gcc
2184 // extension.
2185 if (Type->isVoidType() || Type->isFunctionType()) {
2186 Size = CharUnits::One();
2187 return true;
2188 }
2189
2190 if (Type->isDependentType()) {
2191 Info.FFDiag(Loc);
2192 return false;
2193 }
2194
2195 if (!Type->isConstantSizeType()) {
2196 // sizeof(vla) is not a constantexpr: C99 6.5.3.4p2.
2197 // FIXME: Better diagnostic.
2198 Info.FFDiag(Loc);
2199 return false;
2200 }
2201
2202 Size = Info.Ctx.getTypeSizeInChars(Type);
2203 return true;
2204}
2205
2206/// Update a pointer value to model pointer arithmetic.
2207/// \param Info - Information about the ongoing evaluation.
2208/// \param E - The expression being evaluated, for diagnostic purposes.
2209/// \param LVal - The pointer value to be updated.
2210/// \param EltTy - The pointee type represented by LVal.
2211/// \param Adjustment - The adjustment, in objects of type EltTy, to add.
2212static bool HandleLValueArrayAdjustment(EvalInfo &Info, const Expr *E,
2213 LValue &LVal, QualType EltTy,
2214 int64_t Adjustment) {
2215 CharUnits SizeOfPointee;
2216 if (!HandleSizeof(Info, E->getExprLoc(), EltTy, SizeOfPointee))
2217 return false;
2218
2219 LVal.adjustOffsetAndIndex(Info, E, Adjustment, SizeOfPointee);
2220 return true;
2221}
2222
2223/// Update an lvalue to refer to a component of a complex number.
2224/// \param Info - Information about the ongoing evaluation.
2225/// \param LVal - The lvalue to be updated.
2226/// \param EltTy - The complex number's component type.
2227/// \param Imag - False for the real component, true for the imaginary.
2228static bool HandleLValueComplexElement(EvalInfo &Info, const Expr *E,
2229 LValue &LVal, QualType EltTy,
2230 bool Imag) {
2231 if (Imag) {
2232 CharUnits SizeOfComponent;
2233 if (!HandleSizeof(Info, E->getExprLoc(), EltTy, SizeOfComponent))
2234 return false;
2235 LVal.Offset += SizeOfComponent;
2236 }
2237 LVal.addComplex(Info, E, EltTy, Imag);
2238 return true;
2239}
2240
2241/// Try to evaluate the initializer for a variable declaration.
2242///
2243/// \param Info Information about the ongoing evaluation.
2244/// \param E An expression to be used when printing diagnostics.
2245/// \param VD The variable whose initializer should be obtained.
2246/// \param Frame The frame in which the variable was created. Must be null
2247/// if this variable is not local to the evaluation.
2248/// \param Result Filled in with a pointer to the value of the variable.
2249static bool evaluateVarDeclInit(EvalInfo &Info, const Expr *E,
2250 const VarDecl *VD, CallStackFrame *Frame,
2251 APValue *&Result) {
2252 // If this is a parameter to an active constexpr function call, perform
2253 // argument substitution.
2254 if (const ParmVarDecl *PVD = dyn_cast<ParmVarDecl>(VD)) {
2255 // Assume arguments of a potential constant expression are unknown
2256 // constant expressions.
2257 if (Info.checkingPotentialConstantExpression())
2258 return false;
2259 if (!Frame || !Frame->Arguments) {
2260 Info.FFDiag(E, diag::note_invalid_subexpr_in_const_expr);
2261 return false;
2262 }
2263 Result = &Frame->Arguments[PVD->getFunctionScopeIndex()];
2264 return true;
2265 }
2266
2267 // If this is a local variable, dig out its value.
2268 if (Frame) {
2269 Result = Frame->getTemporary(VD);
2270 if (!Result) {
2271 // Assume variables referenced within a lambda's call operator that were
2272 // not declared within the call operator are captures and during checking
2273 // of a potential constant expression, assume they are unknown constant
2274 // expressions.
2275 assert(isLambdaCallOperator(Frame->Callee) &&((isLambdaCallOperator(Frame->Callee) && (VD->getDeclContext
() != Frame->Callee || VD->isInitCapture()) && "missing value for local variable"
) ? static_cast<void> (0) : __assert_fail ("isLambdaCallOperator(Frame->Callee) && (VD->getDeclContext() != Frame->Callee || VD->isInitCapture()) && \"missing value for local variable\""
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 2277, __PRETTY_FUNCTION__))
2276 (VD->getDeclContext() != Frame->Callee || VD->isInitCapture()) &&((isLambdaCallOperator(Frame->Callee) && (VD->getDeclContext
() != Frame->Callee || VD->isInitCapture()) && "missing value for local variable"
) ? static_cast<void> (0) : __assert_fail ("isLambdaCallOperator(Frame->Callee) && (VD->getDeclContext() != Frame->Callee || VD->isInitCapture()) && \"missing value for local variable\""
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 2277, __PRETTY_FUNCTION__))
2277 "missing value for local variable")((isLambdaCallOperator(Frame->Callee) && (VD->getDeclContext
() != Frame->Callee || VD->isInitCapture()) && "missing value for local variable"
) ? static_cast<void> (0) : __assert_fail ("isLambdaCallOperator(Frame->Callee) && (VD->getDeclContext() != Frame->Callee || VD->isInitCapture()) && \"missing value for local variable\""
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 2277, __PRETTY_FUNCTION__))
;
2278 if (Info.checkingPotentialConstantExpression())
2279 return false;
2280 // FIXME: implement capture evaluation during constant expr evaluation.
2281 Info.FFDiag(E->getLocStart(),
2282 diag::note_unimplemented_constexpr_lambda_feature_ast)
2283 << "captures not currently allowed";
2284 return false;
2285 }
2286 return true;
2287 }
2288
2289 // Dig out the initializer, and use the declaration which it's attached to.
2290 const Expr *Init = VD->getAnyInitializer(VD);
2291 if (!Init || Init->isValueDependent()) {
2292 // If we're checking a potential constant expression, the variable could be
2293 // initialized later.
2294 if (!Info.checkingPotentialConstantExpression())
2295 Info.FFDiag(E, diag::note_invalid_subexpr_in_const_expr);
2296 return false;
2297 }
2298
2299 // If we're currently evaluating the initializer of this declaration, use that
2300 // in-flight value.
2301 if (Info.EvaluatingDecl.dyn_cast<const ValueDecl*>() == VD) {
2302 Result = Info.EvaluatingDeclValue;
2303 return true;
2304 }
2305
2306 // Never evaluate the initializer of a weak variable. We can't be sure that
2307 // this is the definition which will be used.
2308 if (VD->isWeak()) {
2309 Info.FFDiag(E, diag::note_invalid_subexpr_in_const_expr);
2310 return false;
2311 }
2312
2313 // Check that we can fold the initializer. In C++, we will have already done
2314 // this in the cases where it matters for conformance.
2315 SmallVector<PartialDiagnosticAt, 8> Notes;
2316 if (!VD->evaluateValue(Notes)) {
2317 Info.FFDiag(E, diag::note_constexpr_var_init_non_constant,
2318 Notes.size() + 1) << VD;
2319 Info.Note(VD->getLocation(), diag::note_declared_at);
2320 Info.addNotes(Notes);
2321 return false;
2322 } else if (!VD->checkInitIsICE()) {
2323 Info.CCEDiag(E, diag::note_constexpr_var_init_non_constant,
2324 Notes.size() + 1) << VD;
2325 Info.Note(VD->getLocation(), diag::note_declared_at);
2326 Info.addNotes(Notes);
2327 }
2328
2329 Result = VD->getEvaluatedValue();
2330 return true;
2331}
2332
2333static bool IsConstNonVolatile(QualType T) {
2334 Qualifiers Quals = T.getQualifiers();
2335 return Quals.hasConst() && !Quals.hasVolatile();
2336}
2337
2338/// Get the base index of the given base class within an APValue representing
2339/// the given derived class.
2340static unsigned getBaseIndex(const CXXRecordDecl *Derived,
2341 const CXXRecordDecl *Base) {
2342 Base = Base->getCanonicalDecl();
2343 unsigned Index = 0;
2344 for (CXXRecordDecl::base_class_const_iterator I = Derived->bases_begin(),
2345 E = Derived->bases_end(); I != E; ++I, ++Index) {
2346 if (I->getType()->getAsCXXRecordDecl()->getCanonicalDecl() == Base)
2347 return Index;
2348 }
2349
2350 llvm_unreachable("base class missing from derived class's bases list")::llvm::llvm_unreachable_internal("base class missing from derived class's bases list"
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 2350)
;
2351}
2352
2353/// Extract the value of a character from a string literal.
2354static APSInt extractStringLiteralCharacter(EvalInfo &Info, const Expr *Lit,
2355 uint64_t Index) {
2356 // FIXME: Support ObjCEncodeExpr, MakeStringConstant
2357 if (auto PE = dyn_cast<PredefinedExpr>(Lit))
2358 Lit = PE->getFunctionName();
2359 const StringLiteral *S = cast<StringLiteral>(Lit);
2360 const ConstantArrayType *CAT =
2361 Info.Ctx.getAsConstantArrayType(S->getType());
2362 assert(CAT && "string literal isn't an array")((CAT && "string literal isn't an array") ? static_cast
<void> (0) : __assert_fail ("CAT && \"string literal isn't an array\""
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 2362, __PRETTY_FUNCTION__))
;
2363 QualType CharType = CAT->getElementType();
2364 assert(CharType->isIntegerType() && "unexpected character type")((CharType->isIntegerType() && "unexpected character type"
) ? static_cast<void> (0) : __assert_fail ("CharType->isIntegerType() && \"unexpected character type\""
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 2364, __PRETTY_FUNCTION__))
;
2365
2366 APSInt Value(S->getCharByteWidth() * Info.Ctx.getCharWidth(),
2367 CharType->isUnsignedIntegerType());
2368 if (Index < S->getLength())
2369 Value = S->getCodeUnit(Index);
2370 return Value;
2371}
2372
2373// Expand a string literal into an array of characters.
2374static void expandStringLiteral(EvalInfo &Info, const Expr *Lit,
2375 APValue &Result) {
2376 const StringLiteral *S = cast<StringLiteral>(Lit);
2377 const ConstantArrayType *CAT =
2378 Info.Ctx.getAsConstantArrayType(S->getType());
2379 assert(CAT && "string literal isn't an array")((CAT && "string literal isn't an array") ? static_cast
<void> (0) : __assert_fail ("CAT && \"string literal isn't an array\""
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 2379, __PRETTY_FUNCTION__))
;
2380 QualType CharType = CAT->getElementType();
2381 assert(CharType->isIntegerType() && "unexpected character type")((CharType->isIntegerType() && "unexpected character type"
) ? static_cast<void> (0) : __assert_fail ("CharType->isIntegerType() && \"unexpected character type\""
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 2381, __PRETTY_FUNCTION__))
;
2382
2383 unsigned Elts = CAT->getSize().getZExtValue();
2384 Result = APValue(APValue::UninitArray(),
2385 std::min(S->getLength(), Elts), Elts);
2386 APSInt Value(S->getCharByteWidth() * Info.Ctx.getCharWidth(),
2387 CharType->isUnsignedIntegerType());
2388 if (Result.hasArrayFiller())
2389 Result.getArrayFiller() = APValue(Value);
2390 for (unsigned I = 0, N = Result.getArrayInitializedElts(); I != N; ++I) {
2391 Value = S->getCodeUnit(I);
2392 Result.getArrayInitializedElt(I) = APValue(Value);
2393 }
2394}
2395
2396// Expand an array so that it has more than Index filled elements.
2397static void expandArray(APValue &Array, unsigned Index) {
2398 unsigned Size = Array.getArraySize();
2399 assert(Index < Size)((Index < Size) ? static_cast<void> (0) : __assert_fail
("Index < Size", "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 2399, __PRETTY_FUNCTION__))
;
2400
2401 // Always at least double the number of elements for which we store a value.
2402 unsigned OldElts = Array.getArrayInitializedElts();
2403 unsigned NewElts = std::max(Index+1, OldElts * 2);
2404 NewElts = std::min(Size, std::max(NewElts, 8u));
2405
2406 // Copy the data across.
2407 APValue NewValue(APValue::UninitArray(), NewElts, Size);
2408 for (unsigned I = 0; I != OldElts; ++I)
2409 NewValue.getArrayInitializedElt(I).swap(Array.getArrayInitializedElt(I));
2410 for (unsigned I = OldElts; I != NewElts; ++I)
2411 NewValue.getArrayInitializedElt(I) = Array.getArrayFiller();
2412 if (NewValue.hasArrayFiller())
2413 NewValue.getArrayFiller() = Array.getArrayFiller();
2414 Array.swap(NewValue);
2415}
2416
2417/// Determine whether a type would actually be read by an lvalue-to-rvalue
2418/// conversion. If it's of class type, we may assume that the copy operation
2419/// is trivial. Note that this is never true for a union type with fields
2420/// (because the copy always "reads" the active member) and always true for
2421/// a non-class type.
2422static bool isReadByLvalueToRvalueConversion(QualType T) {
2423 CXXRecordDecl *RD = T->getBaseElementTypeUnsafe()->getAsCXXRecordDecl();
2424 if (!RD || (RD->isUnion() && !RD->field_empty()))
2425 return true;
2426 if (RD->isEmpty())
2427 return false;
2428
2429 for (auto *Field : RD->fields())
2430 if (isReadByLvalueToRvalueConversion(Field->getType()))
2431 return true;
2432
2433 for (auto &BaseSpec : RD->bases())
2434 if (isReadByLvalueToRvalueConversion(BaseSpec.getType()))
2435 return true;
2436
2437 return false;
2438}
2439
2440/// Diagnose an attempt to read from any unreadable field within the specified
2441/// type, which might be a class type.
2442static bool diagnoseUnreadableFields(EvalInfo &Info, const Expr *E,
2443 QualType T) {
2444 CXXRecordDecl *RD = T->getBaseElementTypeUnsafe()->getAsCXXRecordDecl();
2445 if (!RD)
2446 return false;
2447
2448 if (!RD->hasMutableFields())
2449 return false;
2450
2451 for (auto *Field : RD->fields()) {
2452 // If we're actually going to read this field in some way, then it can't
2453 // be mutable. If we're in a union, then assigning to a mutable field
2454 // (even an empty one) can change the active member, so that's not OK.
2455 // FIXME: Add core issue number for the union case.
2456 if (Field->isMutable() &&
2457 (RD->isUnion() || isReadByLvalueToRvalueConversion(Field->getType()))) {
2458 Info.FFDiag(E, diag::note_constexpr_ltor_mutable, 1) << Field;
2459 Info.Note(Field->getLocation(), diag::note_declared_at);
2460 return true;
2461 }
2462
2463 if (diagnoseUnreadableFields(Info, E, Field->getType()))
2464 return true;
2465 }
2466
2467 for (auto &BaseSpec : RD->bases())
2468 if (diagnoseUnreadableFields(Info, E, BaseSpec.getType()))
2469 return true;
2470
2471 // All mutable fields were empty, and thus not actually read.
2472 return false;
2473}
2474
2475/// Kinds of access we can perform on an object, for diagnostics.
2476enum AccessKinds {
2477 AK_Read,
2478 AK_Assign,
2479 AK_Increment,
2480 AK_Decrement
2481};
2482
2483namespace {
2484/// A handle to a complete object (an object that is not a subobject of
2485/// another object).
2486struct CompleteObject {
2487 /// The value of the complete object.
2488 APValue *Value;
2489 /// The type of the complete object.
2490 QualType Type;
2491
2492 CompleteObject() : Value(nullptr) {}
2493 CompleteObject(APValue *Value, QualType Type)
2494 : Value(Value), Type(Type) {
2495 assert(Value && "missing value for complete object")((Value && "missing value for complete object") ? static_cast
<void> (0) : __assert_fail ("Value && \"missing value for complete object\""
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 2495, __PRETTY_FUNCTION__))
;
2496 }
2497
2498 explicit operator bool() const { return Value; }
2499};
2500} // end anonymous namespace
2501
2502/// Find the designated sub-object of an rvalue.
2503template<typename SubobjectHandler>
2504typename SubobjectHandler::result_type
2505findSubobject(EvalInfo &Info, const Expr *E, const CompleteObject &Obj,
2506 const SubobjectDesignator &Sub, SubobjectHandler &handler) {
2507 if (Sub.Invalid)
2508 // A diagnostic will have already been produced.
2509 return handler.failed();
2510 if (Sub.isOnePastTheEnd()) {
2511 if (Info.getLangOpts().CPlusPlus11)
2512 Info.FFDiag(E, diag::note_constexpr_access_past_end)
2513 << handler.AccessKind;
2514 else
2515 Info.FFDiag(E);
2516 return handler.failed();
2517 }
2518
2519 APValue *O = Obj.Value;
2520 QualType ObjType = Obj.Type;
2521 const FieldDecl *LastField = nullptr;
2522
2523 // Walk the designator's path to find the subobject.
2524 for (unsigned I = 0, N = Sub.Entries.size(); /**/; ++I) {
2525 if (O->isUninit()) {
2526 if (!Info.checkingPotentialConstantExpression())
2527 Info.FFDiag(E, diag::note_constexpr_access_uninit) << handler.AccessKind;
2528 return handler.failed();
2529 }
2530
2531 if (I == N) {
2532 // If we are reading an object of class type, there may still be more
2533 // things we need to check: if there are any mutable subobjects, we
2534 // cannot perform this read. (This only happens when performing a trivial
2535 // copy or assignment.)
2536 if (ObjType->isRecordType() && handler.AccessKind == AK_Read &&
2537 diagnoseUnreadableFields(Info, E, ObjType))
2538 return handler.failed();
2539
2540 if (!handler.found(*O, ObjType))
2541 return false;
2542
2543 // If we modified a bit-field, truncate it to the right width.
2544 if (handler.AccessKind != AK_Read &&
2545 LastField && LastField->isBitField() &&
2546 !truncateBitfieldValue(Info, E, *O, LastField))
2547 return false;
2548
2549 return true;
2550 }
2551
2552 LastField = nullptr;
2553 if (ObjType->isArrayType()) {
2554 // Next subobject is an array element.
2555 const ConstantArrayType *CAT = Info.Ctx.getAsConstantArrayType(ObjType);
2556 assert(CAT && "vla in literal type?")((CAT && "vla in literal type?") ? static_cast<void
> (0) : __assert_fail ("CAT && \"vla in literal type?\""
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 2556, __PRETTY_FUNCTION__))
;
2557 uint64_t Index = Sub.Entries[I].ArrayIndex;
2558 if (CAT->getSize().ule(Index)) {
2559 // Note, it should not be possible to form a pointer with a valid
2560 // designator which points more than one past the end of the array.
2561 if (Info.getLangOpts().CPlusPlus11)
2562 Info.FFDiag(E, diag::note_constexpr_access_past_end)
2563 << handler.AccessKind;
2564 else
2565 Info.FFDiag(E);
2566 return handler.failed();
2567 }
2568
2569 ObjType = CAT->getElementType();
2570
2571 // An array object is represented as either an Array APValue or as an
2572 // LValue which refers to a string literal.
2573 if (O->isLValue()) {
2574 assert(I == N - 1 && "extracting subobject of character?")((I == N - 1 && "extracting subobject of character?")
? static_cast<void> (0) : __assert_fail ("I == N - 1 && \"extracting subobject of character?\""
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 2574, __PRETTY_FUNCTION__))
;
2575 assert(!O->hasLValuePath() || O->getLValuePath().empty())((!O->hasLValuePath() || O->getLValuePath().empty()) ? static_cast
<void> (0) : __assert_fail ("!O->hasLValuePath() || O->getLValuePath().empty()"
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 2575, __PRETTY_FUNCTION__))
;
2576 if (handler.AccessKind != AK_Read)
2577 expandStringLiteral(Info, O->getLValueBase().get<const Expr *>(),
2578 *O);
2579 else
2580 return handler.foundString(*O, ObjType, Index);
2581 }
2582
2583 if (O->getArrayInitializedElts() > Index)
2584 O = &O->getArrayInitializedElt(Index);
2585 else if (handler.AccessKind != AK_Read) {
2586 expandArray(*O, Index);
2587 O = &O->getArrayInitializedElt(Index);
2588 } else
2589 O = &O->getArrayFiller();
2590 } else if (ObjType->isAnyComplexType()) {
2591 // Next subobject is a complex number.
2592 uint64_t Index = Sub.Entries[I].ArrayIndex;
2593 if (Index > 1) {
2594 if (Info.getLangOpts().CPlusPlus11)
2595 Info.FFDiag(E, diag::note_constexpr_access_past_end)
2596 << handler.AccessKind;
2597 else
2598 Info.FFDiag(E);
2599 return handler.failed();
2600 }
2601
2602 bool WasConstQualified = ObjType.isConstQualified();
2603 ObjType = ObjType->castAs<ComplexType>()->getElementType();
2604 if (WasConstQualified)
2605 ObjType.addConst();
2606
2607 assert(I == N - 1 && "extracting subobject of scalar?")((I == N - 1 && "extracting subobject of scalar?") ? static_cast
<void> (0) : __assert_fail ("I == N - 1 && \"extracting subobject of scalar?\""
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 2607, __PRETTY_FUNCTION__))
;
2608 if (O->isComplexInt()) {
2609 return handler.found(Index ? O->getComplexIntImag()
2610 : O->getComplexIntReal(), ObjType);
2611 } else {
2612 assert(O->isComplexFloat())((O->isComplexFloat()) ? static_cast<void> (0) : __assert_fail
("O->isComplexFloat()", "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 2612, __PRETTY_FUNCTION__))
;
2613 return handler.found(Index ? O->getComplexFloatImag()
2614 : O->getComplexFloatReal(), ObjType);
2615 }
2616 } else if (const FieldDecl *Field = getAsField(Sub.Entries[I])) {
2617 if (Field->isMutable() && handler.AccessKind == AK_Read) {
2618 Info.FFDiag(E, diag::note_constexpr_ltor_mutable, 1)
2619 << Field;
2620 Info.Note(Field->getLocation(), diag::note_declared_at);
2621 return handler.failed();
2622 }
2623
2624 // Next subobject is a class, struct or union field.
2625 RecordDecl *RD = ObjType->castAs<RecordType>()->getDecl();
2626 if (RD->isUnion()) {
2627 const FieldDecl *UnionField = O->getUnionField();
2628 if (!UnionField ||
2629 UnionField->getCanonicalDecl() != Field->getCanonicalDecl()) {
2630 Info.FFDiag(E, diag::note_constexpr_access_inactive_union_member)
2631 << handler.AccessKind << Field << !UnionField << UnionField;
2632 return handler.failed();
2633 }
2634 O = &O->getUnionValue();
2635 } else
2636 O = &O->getStructField(Field->getFieldIndex());
2637
2638 bool WasConstQualified = ObjType.isConstQualified();
2639 ObjType = Field->getType();
2640 if (WasConstQualified && !Field->isMutable())
2641 ObjType.addConst();
2642
2643 if (ObjType.isVolatileQualified()) {
2644 if (Info.getLangOpts().CPlusPlus) {
2645 // FIXME: Include a description of the path to the volatile subobject.
2646 Info.FFDiag(E, diag::note_constexpr_access_volatile_obj, 1)
2647 << handler.AccessKind << 2 << Field;
2648 Info.Note(Field->getLocation(), diag::note_declared_at);
2649 } else {
2650 Info.FFDiag(E, diag::note_invalid_subexpr_in_const_expr);
2651 }
2652 return handler.failed();
2653 }
2654
2655 LastField = Field;
2656 } else {
2657 // Next subobject is a base class.
2658 const CXXRecordDecl *Derived = ObjType->getAsCXXRecordDecl();
2659 const CXXRecordDecl *Base = getAsBaseClass(Sub.Entries[I]);
2660 O = &O->getStructBase(getBaseIndex(Derived, Base));
2661
2662 bool WasConstQualified = ObjType.isConstQualified();
2663 ObjType = Info.Ctx.getRecordType(Base);
2664 if (WasConstQualified)
2665 ObjType.addConst();
2666 }
2667 }
2668}
2669
2670namespace {
2671struct ExtractSubobjectHandler {
2672 EvalInfo &Info;
2673 APValue &Result;
2674
2675 static const AccessKinds AccessKind = AK_Read;
2676
2677 typedef bool result_type;
2678 bool failed() { return false; }
2679 bool found(APValue &Subobj, QualType SubobjType) {
2680 Result = Subobj;
2681 return true;
2682 }
2683 bool found(APSInt &Value, QualType SubobjType) {
2684 Result = APValue(Value);
2685 return true;
2686 }
2687 bool found(APFloat &Value, QualType SubobjType) {
2688 Result = APValue(Value);
2689 return true;
2690 }
2691 bool foundString(APValue &Subobj, QualType SubobjType, uint64_t Character) {
2692 Result = APValue(extractStringLiteralCharacter(
2693 Info, Subobj.getLValueBase().get<const Expr *>(), Character));
2694 return true;
2695 }
2696};
2697} // end anonymous namespace
2698
2699const AccessKinds ExtractSubobjectHandler::AccessKind;
2700
2701/// Extract the designated sub-object of an rvalue.
2702static bool extractSubobject(EvalInfo &Info, const Expr *E,
2703 const CompleteObject &Obj,
2704 const SubobjectDesignator &Sub,
2705 APValue &Result) {
2706 ExtractSubobjectHandler Handler = { Info, Result };
2707 return findSubobject(Info, E, Obj, Sub, Handler);
2708}
2709
2710namespace {
2711struct ModifySubobjectHandler {
2712 EvalInfo &Info;
2713 APValue &NewVal;
2714 const Expr *E;
2715
2716 typedef bool result_type;
2717 static const AccessKinds AccessKind = AK_Assign;
2718
2719 bool checkConst(QualType QT) {
2720 // Assigning to a const object has undefined behavior.
2721 if (QT.isConstQualified()) {
2722 Info.FFDiag(E, diag::note_constexpr_modify_const_type) << QT;
2723 return false;
2724 }
2725 return true;
2726 }
2727
2728 bool failed() { return false; }
2729 bool found(APValue &Subobj, QualType SubobjType) {
2730 if (!checkConst(SubobjType))
2731 return false;
2732 // We've been given ownership of NewVal, so just swap it in.
2733 Subobj.swap(NewVal);
2734 return true;
2735 }
2736 bool found(APSInt &Value, QualType SubobjType) {
2737 if (!checkConst(SubobjType))
2738 return false;
2739 if (!NewVal.isInt()) {
2740 // Maybe trying to write a cast pointer value into a complex?
2741 Info.FFDiag(E);
2742 return false;
2743 }
2744 Value = NewVal.getInt();
2745 return true;
2746 }
2747 bool found(APFloat &Value, QualType SubobjType) {
2748 if (!checkConst(SubobjType))
2749 return false;
2750 Value = NewVal.getFloat();
2751 return true;
2752 }
2753 bool foundString(APValue &Subobj, QualType SubobjType, uint64_t Character) {
2754 llvm_unreachable("shouldn't encounter string elements with ExpandArrays")::llvm::llvm_unreachable_internal("shouldn't encounter string elements with ExpandArrays"
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 2754)
;
2755 }
2756};
2757} // end anonymous namespace
2758
2759const AccessKinds ModifySubobjectHandler::AccessKind;
2760
2761/// Update the designated sub-object of an rvalue to the given value.
2762static bool modifySubobject(EvalInfo &Info, const Expr *E,
2763 const CompleteObject &Obj,
2764 const SubobjectDesignator &Sub,
2765 APValue &NewVal) {
2766 ModifySubobjectHandler Handler = { Info, NewVal, E };
2767 return findSubobject(Info, E, Obj, Sub, Handler);
2768}
2769
2770/// Find the position where two subobject designators diverge, or equivalently
2771/// the length of the common initial subsequence.
2772static unsigned FindDesignatorMismatch(QualType ObjType,
2773 const SubobjectDesignator &A,
2774 const SubobjectDesignator &B,
2775 bool &WasArrayIndex) {
2776 unsigned I = 0, N = std::min(A.Entries.size(), B.Entries.size());
2777 for (/**/; I != N; ++I) {
2778 if (!ObjType.isNull() &&
2779 (ObjType->isArrayType() || ObjType->isAnyComplexType())) {
2780 // Next subobject is an array element.
2781 if (A.Entries[I].ArrayIndex != B.Entries[I].ArrayIndex) {
2782 WasArrayIndex = true;
2783 return I;
2784 }
2785 if (ObjType->isAnyComplexType())
2786 ObjType = ObjType->castAs<ComplexType>()->getElementType();
2787 else
2788 ObjType = ObjType->castAsArrayTypeUnsafe()->getElementType();
2789 } else {
2790 if (A.Entries[I].BaseOrMember != B.Entries[I].BaseOrMember) {
2791 WasArrayIndex = false;
2792 return I;
2793 }
2794 if (const FieldDecl *FD = getAsField(A.Entries[I]))
2795 // Next subobject is a field.
2796 ObjType = FD->getType();
2797 else
2798 // Next subobject is a base class.
2799 ObjType = QualType();
2800 }
2801 }
2802 WasArrayIndex = false;
2803 return I;
2804}
2805
2806/// Determine whether the given subobject designators refer to elements of the
2807/// same array object.
2808static bool AreElementsOfSameArray(QualType ObjType,
2809 const SubobjectDesignator &A,
2810 const SubobjectDesignator &B) {
2811 if (A.Entries.size() != B.Entries.size())
2812 return false;
2813
2814 bool IsArray = A.MostDerivedIsArrayElement;
2815 if (IsArray && A.MostDerivedPathLength != A.Entries.size())
2816 // A is a subobject of the array element.
2817 return false;
2818
2819 // If A (and B) designates an array element, the last entry will be the array
2820 // index. That doesn't have to match. Otherwise, we're in the 'implicit array
2821 // of length 1' case, and the entire path must match.
2822 bool WasArrayIndex;
2823 unsigned CommonLength = FindDesignatorMismatch(ObjType, A, B, WasArrayIndex);
2824 return CommonLength >= A.Entries.size() - IsArray;
2825}
2826
2827/// Find the complete object to which an LValue refers.
2828static CompleteObject findCompleteObject(EvalInfo &Info, const Expr *E,
2829 AccessKinds AK, const LValue &LVal,
2830 QualType LValType) {
2831 if (!LVal.Base) {
2832 Info.FFDiag(E, diag::note_constexpr_access_null) << AK;
2833 return CompleteObject();
2834 }
2835
2836 CallStackFrame *Frame = nullptr;
2837 if (LVal.CallIndex) {
2838 Frame = Info.getCallFrame(LVal.CallIndex);
2839 if (!Frame) {
2840 Info.FFDiag(E, diag::note_constexpr_lifetime_ended, 1)
2841 << AK << LVal.Base.is<const ValueDecl*>();
2842 NoteLValueLocation(Info, LVal.Base);
2843 return CompleteObject();
2844 }
2845 }
2846
2847 // C++11 DR1311: An lvalue-to-rvalue conversion on a volatile-qualified type
2848 // is not a constant expression (even if the object is non-volatile). We also
2849 // apply this rule to C++98, in order to conform to the expected 'volatile'
2850 // semantics.
2851 if (LValType.isVolatileQualified()) {
2852 if (Info.getLangOpts().CPlusPlus)
2853 Info.FFDiag(E, diag::note_constexpr_access_volatile_type)
2854 << AK << LValType;
2855 else
2856 Info.FFDiag(E);
2857 return CompleteObject();
2858 }
2859
2860 // Compute value storage location and type of base object.
2861 APValue *BaseVal = nullptr;
2862 QualType BaseType = getType(LVal.Base);
2863
2864 if (const ValueDecl *D = LVal.Base.dyn_cast<const ValueDecl*>()) {
2865 // In C++98, const, non-volatile integers initialized with ICEs are ICEs.
2866 // In C++11, constexpr, non-volatile variables initialized with constant
2867 // expressions are constant expressions too. Inside constexpr functions,
2868 // parameters are constant expressions even if they're non-const.
2869 // In C++1y, objects local to a constant expression (those with a Frame) are
2870 // both readable and writable inside constant expressions.
2871 // In C, such things can also be folded, although they are not ICEs.
2872 const VarDecl *VD = dyn_cast<VarDecl>(D);
2873 if (VD) {
2874 if (const VarDecl *VDef = VD->getDefinition(Info.Ctx))
2875 VD = VDef;
2876 }
2877 if (!VD || VD->isInvalidDecl()) {
2878 Info.FFDiag(E);
2879 return CompleteObject();
2880 }
2881
2882 // Accesses of volatile-qualified objects are not allowed.
2883 if (BaseType.isVolatileQualified()) {
2884 if (Info.getLangOpts().CPlusPlus) {
2885 Info.FFDiag(E, diag::note_constexpr_access_volatile_obj, 1)
2886 << AK << 1 << VD;
2887 Info.Note(VD->getLocation(), diag::note_declared_at);
2888 } else {
2889 Info.FFDiag(E);
2890 }
2891 return CompleteObject();
2892 }
2893
2894 // Unless we're looking at a local variable or argument in a constexpr call,
2895 // the variable we're reading must be const.
2896 if (!Frame) {
2897 if (Info.getLangOpts().CPlusPlus14 &&
2898 VD == Info.EvaluatingDecl.dyn_cast<const ValueDecl *>()) {
2899 // OK, we can read and modify an object if we're in the process of
2900 // evaluating its initializer, because its lifetime began in this
2901 // evaluation.
2902 } else if (AK != AK_Read) {
2903 // All the remaining cases only permit reading.
2904 Info.FFDiag(E, diag::note_constexpr_modify_global);
2905 return CompleteObject();
2906 } else if (VD->isConstexpr()) {
2907 // OK, we can read this variable.
2908 } else if (BaseType->isIntegralOrEnumerationType()) {
2909 // In OpenCL if a variable is in constant address space it is a const value.
2910 if (!(BaseType.isConstQualified() ||
2911 (Info.getLangOpts().OpenCL &&
2912 BaseType.getAddressSpace() == LangAS::opencl_constant))) {
2913 if (Info.getLangOpts().CPlusPlus) {
2914 Info.FFDiag(E, diag::note_constexpr_ltor_non_const_int, 1) << VD;
2915 Info.Note(VD->getLocation(), diag::note_declared_at);
2916 } else {
2917 Info.FFDiag(E);
2918 }
2919 return CompleteObject();
2920 }
2921 } else if (BaseType->isFloatingType() && BaseType.isConstQualified()) {
2922 // We support folding of const floating-point types, in order to make
2923 // static const data members of such types (supported as an extension)
2924 // more useful.
2925 if (Info.getLangOpts().CPlusPlus11) {
2926 Info.CCEDiag(E, diag::note_constexpr_ltor_non_constexpr, 1) << VD;
2927 Info.Note(VD->getLocation(), diag::note_declared_at);
2928 } else {
2929 Info.CCEDiag(E);
2930 }
2931 } else if (BaseType.isConstQualified() && VD->hasDefinition(Info.Ctx)) {
2932 Info.CCEDiag(E, diag::note_constexpr_ltor_non_constexpr) << VD;
2933 // Keep evaluating to see what we can do.
2934 } else {
2935 // FIXME: Allow folding of values of any literal type in all languages.
2936 if (Info.checkingPotentialConstantExpression() &&
2937 VD->getType().isConstQualified() && !VD->hasDefinition(Info.Ctx)) {
2938 // The definition of this variable could be constexpr. We can't
2939 // access it right now, but may be able to in future.
2940 } else if (Info.getLangOpts().CPlusPlus11) {
2941 Info.FFDiag(E, diag::note_constexpr_ltor_non_constexpr, 1) << VD;
2942 Info.Note(VD->getLocation(), diag::note_declared_at);
2943 } else {
2944 Info.FFDiag(E);
2945 }
2946 return CompleteObject();
2947 }
2948 }
2949
2950 if (!evaluateVarDeclInit(Info, E, VD, Frame, BaseVal))
2951 return CompleteObject();
2952 } else {
2953 const Expr *Base = LVal.Base.dyn_cast<const Expr*>();
2954
2955 if (!Frame) {
2956 if (const MaterializeTemporaryExpr *MTE =
2957 dyn_cast<MaterializeTemporaryExpr>(Base)) {
2958 assert(MTE->getStorageDuration() == SD_Static &&((MTE->getStorageDuration() == SD_Static && "should have a frame for a non-global materialized temporary"
) ? static_cast<void> (0) : __assert_fail ("MTE->getStorageDuration() == SD_Static && \"should have a frame for a non-global materialized temporary\""
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 2959, __PRETTY_FUNCTION__))
2959 "should have a frame for a non-global materialized temporary")((MTE->getStorageDuration() == SD_Static && "should have a frame for a non-global materialized temporary"
) ? static_cast<void> (0) : __assert_fail ("MTE->getStorageDuration() == SD_Static && \"should have a frame for a non-global materialized temporary\""
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 2959, __PRETTY_FUNCTION__))
;
2960
2961 // Per C++1y [expr.const]p2:
2962 // an lvalue-to-rvalue conversion [is not allowed unless it applies to]
2963 // - a [...] glvalue of integral or enumeration type that refers to
2964 // a non-volatile const object [...]
2965 // [...]
2966 // - a [...] glvalue of literal type that refers to a non-volatile
2967 // object whose lifetime began within the evaluation of e.
2968 //
2969 // C++11 misses the 'began within the evaluation of e' check and
2970 // instead allows all temporaries, including things like:
2971 // int &&r = 1;
2972 // int x = ++r;
2973 // constexpr int k = r;
2974 // Therefore we use the C++1y rules in C++11 too.
2975 const ValueDecl *VD = Info.EvaluatingDecl.dyn_cast<const ValueDecl*>();
2976 const ValueDecl *ED = MTE->getExtendingDecl();
2977 if (!(BaseType.isConstQualified() &&
2978 BaseType->isIntegralOrEnumerationType()) &&
2979 !(VD && VD->getCanonicalDecl() == ED->getCanonicalDecl())) {
2980 Info.FFDiag(E, diag::note_constexpr_access_static_temporary, 1) << AK;
2981 Info.Note(MTE->getExprLoc(), diag::note_constexpr_temporary_here);
2982 return CompleteObject();
2983 }
2984
2985 BaseVal = Info.Ctx.getMaterializedTemporaryValue(MTE, false);
2986 assert(BaseVal && "got reference to unevaluated temporary")((BaseVal && "got reference to unevaluated temporary"
) ? static_cast<void> (0) : __assert_fail ("BaseVal && \"got reference to unevaluated temporary\""
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 2986, __PRETTY_FUNCTION__))
;
2987 } else {
2988 Info.FFDiag(E);
2989 return CompleteObject();
2990 }
2991 } else {
2992 BaseVal = Frame->getTemporary(Base);
2993 assert(BaseVal && "missing value for temporary")((BaseVal && "missing value for temporary") ? static_cast
<void> (0) : __assert_fail ("BaseVal && \"missing value for temporary\""
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 2993, __PRETTY_FUNCTION__))
;
2994 }
2995
2996 // Volatile temporary objects cannot be accessed in constant expressions.
2997 if (BaseType.isVolatileQualified()) {
2998 if (Info.getLangOpts().CPlusPlus) {
2999 Info.FFDiag(E, diag::note_constexpr_access_volatile_obj, 1)
3000 << AK << 0;
3001 Info.Note(Base->getExprLoc(), diag::note_constexpr_temporary_here);
3002 } else {
3003 Info.FFDiag(E);
3004 }
3005 return CompleteObject();
3006 }
3007 }
3008
3009 // During the construction of an object, it is not yet 'const'.
3010 // FIXME: We don't set up EvaluatingDecl for local variables or temporaries,
3011 // and this doesn't do quite the right thing for const subobjects of the
3012 // object under construction.
3013 if (LVal.getLValueBase() == Info.EvaluatingDecl) {
3014 BaseType = Info.Ctx.getCanonicalType(BaseType);
3015 BaseType.removeLocalConst();
3016 }
3017
3018 // In C++1y, we can't safely access any mutable state when we might be
3019 // evaluating after an unmodeled side effect.
3020 //
3021 // FIXME: Not all local state is mutable. Allow local constant subobjects
3022 // to be read here (but take care with 'mutable' fields).
3023 if ((Frame && Info.getLangOpts().CPlusPlus14 &&
3024 Info.EvalStatus.HasSideEffects) ||
3025 (AK != AK_Read && Info.IsSpeculativelyEvaluating))
3026 return CompleteObject();
3027
3028 return CompleteObject(BaseVal, BaseType);
3029}
3030
3031/// \brief Perform an lvalue-to-rvalue conversion on the given glvalue. This
3032/// can also be used for 'lvalue-to-lvalue' conversions for looking up the
3033/// glvalue referred to by an entity of reference type.
3034///
3035/// \param Info - Information about the ongoing evaluation.
3036/// \param Conv - The expression for which we are performing the conversion.
3037/// Used for diagnostics.
3038/// \param Type - The type of the glvalue (before stripping cv-qualifiers in the
3039/// case of a non-class type).
3040/// \param LVal - The glvalue on which we are attempting to perform this action.
3041/// \param RVal - The produced value will be placed here.
3042static bool handleLValueToRValueConversion(EvalInfo &Info, const Expr *Conv,
3043 QualType Type,
3044 const LValue &LVal, APValue &RVal) {
3045 if (LVal.Designator.Invalid)
3046 return false;
3047
3048 // Check for special cases where there is no existing APValue to look at.
3049 const Expr *Base = LVal.Base.dyn_cast<const Expr*>();
3050 if (Base && !LVal.CallIndex && !Type.isVolatileQualified()) {
3051 if (const CompoundLiteralExpr *CLE = dyn_cast<CompoundLiteralExpr>(Base)) {
3052 // In C99, a CompoundLiteralExpr is an lvalue, and we defer evaluating the
3053 // initializer until now for such expressions. Such an expression can't be
3054 // an ICE in C, so this only matters for fold.
3055 if (Type.isVolatileQualified()) {
3056 Info.FFDiag(Conv);
3057 return false;
3058 }
3059 APValue Lit;
3060 if (!Evaluate(Lit, Info, CLE->getInitializer()))
3061 return false;
3062 CompleteObject LitObj(&Lit, Base->getType());
3063 return extractSubobject(Info, Conv, LitObj, LVal.Designator, RVal);
3064 } else if (isa<StringLiteral>(Base) || isa<PredefinedExpr>(Base)) {
3065 // We represent a string literal array as an lvalue pointing at the
3066 // corresponding expression, rather than building an array of chars.
3067 // FIXME: Support ObjCEncodeExpr, MakeStringConstant
3068 APValue Str(Base, CharUnits::Zero(), APValue::NoLValuePath(), 0);
3069 CompleteObject StrObj(&Str, Base->getType());
3070 return extractSubobject(Info, Conv, StrObj, LVal.Designator, RVal);
3071 }
3072 }
3073
3074 CompleteObject Obj = findCompleteObject(Info, Conv, AK_Read, LVal, Type);
3075 return Obj && extractSubobject(Info, Conv, Obj, LVal.Designator, RVal);
3076}
3077
3078/// Perform an assignment of Val to LVal. Takes ownership of Val.
3079static bool handleAssignment(EvalInfo &Info, const Expr *E, const LValue &LVal,
3080 QualType LValType, APValue &Val) {
3081 if (LVal.Designator.Invalid)
3082 return false;
3083
3084 if (!Info.getLangOpts().CPlusPlus14) {
3085 Info.FFDiag(E);
3086 return false;
3087 }
3088
3089 CompleteObject Obj = findCompleteObject(Info, E, AK_Assign, LVal, LValType);
3090 return Obj && modifySubobject(Info, E, Obj, LVal.Designator, Val);
3091}
3092
3093static bool isOverflowingIntegerType(ASTContext &Ctx, QualType T) {
3094 return T->isSignedIntegerType() &&
3095 Ctx.getIntWidth(T) >= Ctx.getIntWidth(Ctx.IntTy);
3096}
3097
3098namespace {
3099struct CompoundAssignSubobjectHandler {
3100 EvalInfo &Info;
3101 const Expr *E;
3102 QualType PromotedLHSType;
3103 BinaryOperatorKind Opcode;
3104 const APValue &RHS;
3105
3106 static const AccessKinds AccessKind = AK_Assign;
3107
3108 typedef bool result_type;
3109
3110 bool checkConst(QualType QT) {
3111 // Assigning to a const object has undefined behavior.
3112 if (QT.isConstQualified()) {
3113 Info.FFDiag(E, diag::note_constexpr_modify_const_type) << QT;
3114 return false;
3115 }
3116 return true;
3117 }
3118
3119 bool failed() { return false; }
3120 bool found(APValue &Subobj, QualType SubobjType) {
3121 switch (Subobj.getKind()) {
3122 case APValue::Int:
3123 return found(Subobj.getInt(), SubobjType);
3124 case APValue::Float:
3125 return found(Subobj.getFloat(), SubobjType);
3126 case APValue::ComplexInt:
3127 case APValue::ComplexFloat:
3128 // FIXME: Implement complex compound assignment.
3129 Info.FFDiag(E);
3130 return false;
3131 case APValue::LValue:
3132 return foundPointer(Subobj, SubobjType);
3133 default:
3134 // FIXME: can this happen?
3135 Info.FFDiag(E);
3136 return false;
3137 }
3138 }
3139 bool found(APSInt &Value, QualType SubobjType) {
3140 if (!checkConst(SubobjType))
3141 return false;
3142
3143 if (!SubobjType->isIntegerType() || !RHS.isInt()) {
3144 // We don't support compound assignment on integer-cast-to-pointer
3145 // values.
3146 Info.FFDiag(E);
3147 return false;
3148 }
3149
3150 APSInt LHS = HandleIntToIntCast(Info, E, PromotedLHSType,
3151 SubobjType, Value);
3152 if (!handleIntIntBinOp(Info, E, LHS, Opcode, RHS.getInt(), LHS))
3153 return false;
3154 Value = HandleIntToIntCast(Info, E, SubobjType, PromotedLHSType, LHS);
3155 return true;
3156 }
3157 bool found(APFloat &Value, QualType SubobjType) {
3158 return checkConst(SubobjType) &&
3159 HandleFloatToFloatCast(Info, E, SubobjType, PromotedLHSType,
3160 Value) &&
3161 handleFloatFloatBinOp(Info, E, Value, Opcode, RHS.getFloat()) &&
3162 HandleFloatToFloatCast(Info, E, PromotedLHSType, SubobjType, Value);
3163 }
3164 bool foundPointer(APValue &Subobj, QualType SubobjType) {
3165 if (!checkConst(SubobjType))
3166 return false;
3167
3168 QualType PointeeType;
3169 if (const PointerType *PT = SubobjType->getAs<PointerType>())
3170 PointeeType = PT->getPointeeType();
3171
3172 if (PointeeType.isNull() || !RHS.isInt() ||
3173 (Opcode != BO_Add && Opcode != BO_Sub)) {
3174 Info.FFDiag(E);
3175 return false;
3176 }
3177
3178 int64_t Offset = getExtValue(RHS.getInt());
3179 if (Opcode == BO_Sub)
3180 Offset = -Offset;
3181
3182 LValue LVal;
3183 LVal.setFrom(Info.Ctx, Subobj);
3184 if (!HandleLValueArrayAdjustment(Info, E, LVal, PointeeType, Offset))
3185 return false;
3186 LVal.moveInto(Subobj);
3187 return true;
3188 }
3189 bool foundString(APValue &Subobj, QualType SubobjType, uint64_t Character) {
3190 llvm_unreachable("shouldn't encounter string elements here")::llvm::llvm_unreachable_internal("shouldn't encounter string elements here"
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 3190)
;
3191 }
3192};
3193} // end anonymous namespace
3194
3195const AccessKinds CompoundAssignSubobjectHandler::AccessKind;
3196
3197/// Perform a compound assignment of LVal <op>= RVal.
3198static bool handleCompoundAssignment(
3199 EvalInfo &Info, const Expr *E,
3200 const LValue &LVal, QualType LValType, QualType PromotedLValType,
3201 BinaryOperatorKind Opcode, const APValue &RVal) {
3202 if (LVal.Designator.Invalid)
3203 return false;
3204
3205 if (!Info.getLangOpts().CPlusPlus14) {
3206 Info.FFDiag(E);
3207 return false;
3208 }
3209
3210 CompleteObject Obj = findCompleteObject(Info, E, AK_Assign, LVal, LValType);
3211 CompoundAssignSubobjectHandler Handler = { Info, E, PromotedLValType, Opcode,
3212 RVal };
3213 return Obj && findSubobject(Info, E, Obj, LVal.Designator, Handler);
3214}
3215
3216namespace {
3217struct IncDecSubobjectHandler {
3218 EvalInfo &Info;
3219 const Expr *E;
3220 AccessKinds AccessKind;
3221 APValue *Old;
3222
3223 typedef bool result_type;
3224
3225 bool checkConst(QualType QT) {
3226 // Assigning to a const object has undefined behavior.
3227 if (QT.isConstQualified()) {
3228 Info.FFDiag(E, diag::note_constexpr_modify_const_type) << QT;
3229 return false;
3230 }
3231 return true;
3232 }
3233
3234 bool failed() { return false; }
3235 bool found(APValue &Subobj, QualType SubobjType) {
3236 // Stash the old value. Also clear Old, so we don't clobber it later
3237 // if we're post-incrementing a complex.
3238 if (Old) {
3239 *Old = Subobj;
3240 Old = nullptr;
3241 }
3242
3243 switch (Subobj.getKind()) {
3244 case APValue::Int:
3245 return found(Subobj.getInt(), SubobjType);
3246 case APValue::Float:
3247 return found(Subobj.getFloat(), SubobjType);
3248 case APValue::ComplexInt:
3249 return found(Subobj.getComplexIntReal(),
3250 SubobjType->castAs<ComplexType>()->getElementType()
3251 .withCVRQualifiers(SubobjType.getCVRQualifiers()));
3252 case APValue::ComplexFloat:
3253 return found(Subobj.getComplexFloatReal(),
3254 SubobjType->castAs<ComplexType>()->getElementType()
3255 .withCVRQualifiers(SubobjType.getCVRQualifiers()));
3256 case APValue::LValue:
3257 return foundPointer(Subobj, SubobjType);
3258 default:
3259 // FIXME: can this happen?
3260 Info.FFDiag(E);
3261 return false;
3262 }
3263 }
3264 bool found(APSInt &Value, QualType SubobjType) {
3265 if (!checkConst(SubobjType))
3266 return false;
3267
3268 if (!SubobjType->isIntegerType()) {
3269 // We don't support increment / decrement on integer-cast-to-pointer
3270 // values.
3271 Info.FFDiag(E);
3272 return false;
3273 }
3274
3275 if (Old) *Old = APValue(Value);
3276
3277 // bool arithmetic promotes to int, and the conversion back to bool
3278 // doesn't reduce mod 2^n, so special-case it.
3279 if (SubobjType->isBooleanType()) {
3280 if (AccessKind == AK_Increment)
3281 Value = 1;
3282 else
3283 Value = !Value;
3284 return true;
3285 }
3286
3287 bool WasNegative = Value.isNegative();
3288 if (AccessKind == AK_Increment) {
3289 ++Value;
3290
3291 if (!WasNegative && Value.isNegative() &&
3292 isOverflowingIntegerType(Info.Ctx, SubobjType)) {
3293 APSInt ActualValue(Value, /*IsUnsigned*/true);
3294 return HandleOverflow(Info, E, ActualValue, SubobjType);
3295 }
3296 } else {
3297 --Value;
3298
3299 if (WasNegative && !Value.isNegative() &&
3300 isOverflowingIntegerType(Info.Ctx, SubobjType)) {
3301 unsigned BitWidth = Value.getBitWidth();
3302 APSInt ActualValue(Value.sext(BitWidth + 1), /*IsUnsigned*/false);
3303 ActualValue.setBit(BitWidth);
3304 return HandleOverflow(Info, E, ActualValue, SubobjType);
3305 }
3306 }
3307 return true;
3308 }
3309 bool found(APFloat &Value, QualType SubobjType) {
3310 if (!checkConst(SubobjType))
3311 return false;
3312
3313 if (Old) *Old = APValue(Value);
3314
3315 APFloat One(Value.getSemantics(), 1);
3316 if (AccessKind == AK_Increment)
3317 Value.add(One, APFloat::rmNearestTiesToEven);
3318 else
3319 Value.subtract(One, APFloat::rmNearestTiesToEven);
3320 return true;
3321 }
3322 bool foundPointer(APValue &Subobj, QualType SubobjType) {
3323 if (!checkConst(SubobjType))
3324 return false;
3325
3326 QualType PointeeType;
3327 if (const PointerType *PT = SubobjType->getAs<PointerType>())
3328 PointeeType = PT->getPointeeType();
3329 else {
3330 Info.FFDiag(E);
3331 return false;
3332 }
3333
3334 LValue LVal;
3335 LVal.setFrom(Info.Ctx, Subobj);
3336 if (!HandleLValueArrayAdjustment(Info, E, LVal, PointeeType,
3337 AccessKind == AK_Increment ? 1 : -1))
3338 return false;
3339 LVal.moveInto(Subobj);
3340 return true;
3341 }
3342 bool foundString(APValue &Subobj, QualType SubobjType, uint64_t Character) {
3343 llvm_unreachable("shouldn't encounter string elements here")::llvm::llvm_unreachable_internal("shouldn't encounter string elements here"
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 3343)
;
3344 }
3345};
3346} // end anonymous namespace
3347
3348/// Perform an increment or decrement on LVal.
3349static bool handleIncDec(EvalInfo &Info, const Expr *E, const LValue &LVal,
3350 QualType LValType, bool IsIncrement, APValue *Old) {
3351 if (LVal.Designator.Invalid)
3352 return false;
3353
3354 if (!Info.getLangOpts().CPlusPlus14) {
3355 Info.FFDiag(E);
3356 return false;
3357 }
3358
3359 AccessKinds AK = IsIncrement ? AK_Increment : AK_Decrement;
3360 CompleteObject Obj = findCompleteObject(Info, E, AK, LVal, LValType);
3361 IncDecSubobjectHandler Handler = { Info, E, AK, Old };
3362 return Obj && findSubobject(Info, E, Obj, LVal.Designator, Handler);
3363}
3364
3365/// Build an lvalue for the object argument of a member function call.
3366static bool EvaluateObjectArgument(EvalInfo &Info, const Expr *Object,
3367 LValue &This) {
3368 if (Object->getType()->isPointerType())
3369 return EvaluatePointer(Object, This, Info);
3370
3371 if (Object->isGLValue())
3372 return EvaluateLValue(Object, This, Info);
3373
3374 if (Object->getType()->isLiteralType(Info.Ctx))
3375 return EvaluateTemporary(Object, This, Info);
3376
3377 Info.FFDiag(Object, diag::note_constexpr_nonliteral) << Object->getType();
3378 return false;
3379}
3380
3381/// HandleMemberPointerAccess - Evaluate a member access operation and build an
3382/// lvalue referring to the result.
3383///
3384/// \param Info - Information about the ongoing evaluation.
3385/// \param LV - An lvalue referring to the base of the member pointer.
3386/// \param RHS - The member pointer expression.
3387/// \param IncludeMember - Specifies whether the member itself is included in
3388/// the resulting LValue subobject designator. This is not possible when
3389/// creating a bound member function.
3390/// \return The field or method declaration to which the member pointer refers,
3391/// or 0 if evaluation fails.
3392static const ValueDecl *HandleMemberPointerAccess(EvalInfo &Info,
3393 QualType LVType,
3394 LValue &LV,
3395 const Expr *RHS,
3396 bool IncludeMember = true) {
3397 MemberPtr MemPtr;
3398 if (!EvaluateMemberPointer(RHS, MemPtr, Info))
3399 return nullptr;
3400
3401 // C++11 [expr.mptr.oper]p6: If the second operand is the null pointer to
3402 // member value, the behavior is undefined.
3403 if (!MemPtr.getDecl()) {
3404 // FIXME: Specific diagnostic.
3405 Info.FFDiag(RHS);
3406 return nullptr;
3407 }
3408
3409 if (MemPtr.isDerivedMember()) {
3410 // This is a member of some derived class. Truncate LV appropriately.
3411 // The end of the derived-to-base path for the base object must match the
3412 // derived-to-base path for the member pointer.
3413 if (LV.Designator.MostDerivedPathLength + MemPtr.Path.size() >
3414 LV.Designator.Entries.size()) {
3415 Info.FFDiag(RHS);
3416 return nullptr;
3417 }
3418 unsigned PathLengthToMember =
3419 LV.Designator.Entries.size() - MemPtr.Path.size();
3420 for (unsigned I = 0, N = MemPtr.Path.size(); I != N; ++I) {
3421 const CXXRecordDecl *LVDecl = getAsBaseClass(
3422 LV.Designator.Entries[PathLengthToMember + I]);
3423 const CXXRecordDecl *MPDecl = MemPtr.Path[I];
3424 if (LVDecl->getCanonicalDecl() != MPDecl->getCanonicalDecl()) {
3425 Info.FFDiag(RHS);
3426 return nullptr;
3427 }
3428 }
3429
3430 // Truncate the lvalue to the appropriate derived class.
3431 if (!CastToDerivedClass(Info, RHS, LV, MemPtr.getContainingRecord(),
3432 PathLengthToMember))
3433 return nullptr;
3434 } else if (!MemPtr.Path.empty()) {
3435 // Extend the LValue path with the member pointer's path.
3436 LV.Designator.Entries.reserve(LV.Designator.Entries.size() +
3437 MemPtr.Path.size() + IncludeMember);
3438
3439 // Walk down to the appropriate base class.
3440 if (const PointerType *PT = LVType->getAs<PointerType>())
3441 LVType = PT->getPointeeType();
3442 const CXXRecordDecl *RD = LVType->getAsCXXRecordDecl();
3443 assert(RD && "member pointer access on non-class-type expression")((RD && "member pointer access on non-class-type expression"
) ? static_cast<void> (0) : __assert_fail ("RD && \"member pointer access on non-class-type expression\""
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 3443, __PRETTY_FUNCTION__))
;
3444 // The first class in the path is that of the lvalue.
3445 for (unsigned I = 1, N = MemPtr.Path.size(); I != N; ++I) {
3446 const CXXRecordDecl *Base = MemPtr.Path[N - I - 1];
3447 if (!HandleLValueDirectBase(Info, RHS, LV, RD, Base))
3448 return nullptr;
3449 RD = Base;
3450 }
3451 // Finally cast to the class containing the member.
3452 if (!HandleLValueDirectBase(Info, RHS, LV, RD,
3453 MemPtr.getContainingRecord()))
3454 return nullptr;
3455 }
3456
3457 // Add the member. Note that we cannot build bound member functions here.
3458 if (IncludeMember) {
3459 if (const FieldDecl *FD = dyn_cast<FieldDecl>(MemPtr.getDecl())) {
3460 if (!HandleLValueMember(Info, RHS, LV, FD))
3461 return nullptr;
3462 } else if (const IndirectFieldDecl *IFD =
3463 dyn_cast<IndirectFieldDecl>(MemPtr.getDecl())) {
3464 if (!HandleLValueIndirectMember(Info, RHS, LV, IFD))
3465 return nullptr;
3466 } else {
3467 llvm_unreachable("can't construct reference to bound member function")::llvm::llvm_unreachable_internal("can't construct reference to bound member function"
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 3467)
;
3468 }
3469 }
3470
3471 return MemPtr.getDecl();
3472}
3473
3474static const ValueDecl *HandleMemberPointerAccess(EvalInfo &Info,
3475 const BinaryOperator *BO,
3476 LValue &LV,
3477 bool IncludeMember = true) {
3478 assert(BO->getOpcode() == BO_PtrMemD || BO->getOpcode() == BO_PtrMemI)((BO->getOpcode() == BO_PtrMemD || BO->getOpcode() == BO_PtrMemI
) ? static_cast<void> (0) : __assert_fail ("BO->getOpcode() == BO_PtrMemD || BO->getOpcode() == BO_PtrMemI"
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 3478, __PRETTY_FUNCTION__))
;
3479
3480 if (!EvaluateObjectArgument(Info, BO->getLHS(), LV)) {
3481 if (Info.noteFailure()) {
3482 MemberPtr MemPtr;
3483 EvaluateMemberPointer(BO->getRHS(), MemPtr, Info);
3484 }
3485 return nullptr;
3486 }
3487
3488 return HandleMemberPointerAccess(Info, BO->getLHS()->getType(), LV,
3489 BO->getRHS(), IncludeMember);
3490}
3491
3492/// HandleBaseToDerivedCast - Apply the given base-to-derived cast operation on
3493/// the provided lvalue, which currently refers to the base object.
3494static bool HandleBaseToDerivedCast(EvalInfo &Info, const CastExpr *E,
3495 LValue &Result) {
3496 SubobjectDesignator &D = Result.Designator;
3497 if (D.Invalid || !Result.checkNullPointer(Info, E, CSK_Derived))
3498 return false;
3499
3500 QualType TargetQT = E->getType();
3501 if (const PointerType *PT = TargetQT->getAs<PointerType>())
3502 TargetQT = PT->getPointeeType();
3503
3504 // Check this cast lands within the final derived-to-base subobject path.
3505 if (D.MostDerivedPathLength + E->path_size() > D.Entries.size()) {
3506 Info.CCEDiag(E, diag::note_constexpr_invalid_downcast)
3507 << D.MostDerivedType << TargetQT;
3508 return false;
3509 }
3510
3511 // Check the type of the final cast. We don't need to check the path,
3512 // since a cast can only be formed if the path is unique.
3513 unsigned NewEntriesSize = D.Entries.size() - E->path_size();
3514 const CXXRecordDecl *TargetType = TargetQT->getAsCXXRecordDecl();
3515 const CXXRecordDecl *FinalType;
3516 if (NewEntriesSize == D.MostDerivedPathLength)
3517 FinalType = D.MostDerivedType->getAsCXXRecordDecl();
3518 else
3519 FinalType = getAsBaseClass(D.Entries[NewEntriesSize - 1]);
3520 if (FinalType->getCanonicalDecl() != TargetType->getCanonicalDecl()) {
3521 Info.CCEDiag(E, diag::note_constexpr_invalid_downcast)
3522 << D.MostDerivedType << TargetQT;
3523 return false;
3524 }
3525
3526 // Truncate the lvalue to the appropriate derived class.
3527 return CastToDerivedClass(Info, E, Result, TargetType, NewEntriesSize);
3528}
3529
3530namespace {
3531enum EvalStmtResult {
3532 /// Evaluation failed.
3533 ESR_Failed,
3534 /// Hit a 'return' statement.
3535 ESR_Returned,
3536 /// Evaluation succeeded.
3537 ESR_Succeeded,
3538 /// Hit a 'continue' statement.
3539 ESR_Continue,
3540 /// Hit a 'break' statement.
3541 ESR_Break,
3542 /// Still scanning for 'case' or 'default' statement.
3543 ESR_CaseNotFound
3544};
3545}
3546
3547static bool EvaluateVarDecl(EvalInfo &Info, const VarDecl *VD) {
3548 // We don't need to evaluate the initializer for a static local.
3549 if (!VD->hasLocalStorage())
3550 return true;
3551
3552 LValue Result;
3553 Result.set(VD, Info.CurrentCall->Index);
3554 APValue &Val = Info.CurrentCall->createTemporary(VD, true);
3555
3556 const Expr *InitE = VD->getInit();
3557 if (!InitE) {
3558 Info.FFDiag(VD->getLocStart(), diag::note_constexpr_uninitialized)
3559 << false << VD->getType();
3560 Val = APValue();
3561 return false;
3562 }
3563
3564 if (InitE->isValueDependent())
3565 return false;
3566
3567 if (!EvaluateInPlace(Val, Info, Result, InitE)) {
3568 // Wipe out any partially-computed value, to allow tracking that this
3569 // evaluation failed.
3570 Val = APValue();
3571 return false;
3572 }
3573
3574 return true;
3575}
3576
3577static bool EvaluateDecl(EvalInfo &Info, const Decl *D) {
3578 bool OK = true;
3579
3580 if (const VarDecl *VD = dyn_cast<VarDecl>(D))
3581 OK &= EvaluateVarDecl(Info, VD);
3582
3583 if (const DecompositionDecl *DD = dyn_cast<DecompositionDecl>(D))
3584 for (auto *BD : DD->bindings())
3585 if (auto *VD = BD->getHoldingVar())
3586 OK &= EvaluateDecl(Info, VD);
3587
3588 return OK;
3589}
3590
3591
3592/// Evaluate a condition (either a variable declaration or an expression).
3593static bool EvaluateCond(EvalInfo &Info, const VarDecl *CondDecl,
3594 const Expr *Cond, bool &Result) {
3595 FullExpressionRAII Scope(Info);
3596 if (CondDecl && !EvaluateDecl(Info, CondDecl))
3597 return false;
3598 return EvaluateAsBooleanCondition(Cond, Result, Info);
3599}
3600
3601namespace {
3602/// \brief A location where the result (returned value) of evaluating a
3603/// statement should be stored.
3604struct StmtResult {
3605 /// The APValue that should be filled in with the returned value.
3606 APValue &Value;
3607 /// The location containing the result, if any (used to support RVO).
3608 const LValue *Slot;
3609};
3610}
3611
3612static EvalStmtResult EvaluateStmt(StmtResult &Result, EvalInfo &Info,
3613 const Stmt *S,
3614 const SwitchCase *SC = nullptr);
3615
3616/// Evaluate the body of a loop, and translate the result as appropriate.
3617static EvalStmtResult EvaluateLoopBody(StmtResult &Result, EvalInfo &Info,
3618 const Stmt *Body,
3619 const SwitchCase *Case = nullptr) {
3620 BlockScopeRAII Scope(Info);
3621 switch (EvalStmtResult ESR = EvaluateStmt(Result, Info, Body, Case)) {
3622 case ESR_Break:
3623 return ESR_Succeeded;
3624 case ESR_Succeeded:
3625 case ESR_Continue:
3626 return ESR_Continue;
3627 case ESR_Failed:
3628 case ESR_Returned:
3629 case ESR_CaseNotFound:
3630 return ESR;
3631 }
3632 llvm_unreachable("Invalid EvalStmtResult!")::llvm::llvm_unreachable_internal("Invalid EvalStmtResult!", "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 3632)
;
3633}
3634
3635/// Evaluate a switch statement.
3636static EvalStmtResult EvaluateSwitch(StmtResult &Result, EvalInfo &Info,
3637 const SwitchStmt *SS) {
3638 BlockScopeRAII Scope(Info);
3639
3640 // Evaluate the switch condition.
3641 APSInt Value;
3642 {
3643 FullExpressionRAII Scope(Info);
3644 if (const Stmt *Init = SS->getInit()) {
3645 EvalStmtResult ESR = EvaluateStmt(Result, Info, Init);
3646 if (ESR != ESR_Succeeded)
3647 return ESR;
3648 }
3649 if (SS->getConditionVariable() &&
3650 !EvaluateDecl(Info, SS->getConditionVariable()))
3651 return ESR_Failed;
3652 if (!EvaluateInteger(SS->getCond(), Value, Info))
3653 return ESR_Failed;
3654 }
3655
3656 // Find the switch case corresponding to the value of the condition.
3657 // FIXME: Cache this lookup.
3658 const SwitchCase *Found = nullptr;
3659 for (const SwitchCase *SC = SS->getSwitchCaseList(); SC;
3660 SC = SC->getNextSwitchCase()) {
3661 if (isa<DefaultStmt>(SC)) {
3662 Found = SC;
3663 continue;
3664 }
3665
3666 const CaseStmt *CS = cast<CaseStmt>(SC);
3667 APSInt LHS = CS->getLHS()->EvaluateKnownConstInt(Info.Ctx);
3668 APSInt RHS = CS->getRHS() ? CS->getRHS()->EvaluateKnownConstInt(Info.Ctx)
3669 : LHS;
3670 if (LHS <= Value && Value <= RHS) {
3671 Found = SC;
3672 break;
3673 }
3674 }
3675
3676 if (!Found)
3677 return ESR_Succeeded;
3678
3679 // Search the switch body for the switch case and evaluate it from there.
3680 switch (EvalStmtResult ESR = EvaluateStmt(Result, Info, SS->getBody(), Found)) {
3681 case ESR_Break:
3682 return ESR_Succeeded;
3683 case ESR_Succeeded:
3684 case ESR_Continue:
3685 case ESR_Failed:
3686 case ESR_Returned:
3687 return ESR;
3688 case ESR_CaseNotFound:
3689 // This can only happen if the switch case is nested within a statement
3690 // expression. We have no intention of supporting that.
3691 Info.FFDiag(Found->getLocStart(), diag::note_constexpr_stmt_expr_unsupported);
3692 return ESR_Failed;
3693 }
3694 llvm_unreachable("Invalid EvalStmtResult!")::llvm::llvm_unreachable_internal("Invalid EvalStmtResult!", "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 3694)
;
3695}
3696
3697// Evaluate a statement.
3698static EvalStmtResult EvaluateStmt(StmtResult &Result, EvalInfo &Info,
3699 const Stmt *S, const SwitchCase *Case) {
3700 if (!Info.nextStep(S))
3701 return ESR_Failed;
3702
3703 // If we're hunting down a 'case' or 'default' label, recurse through
3704 // substatements until we hit the label.
3705 if (Case) {
3706 // FIXME: We don't start the lifetime of objects whose initialization we
3707 // jump over. However, such objects must be of class type with a trivial
3708 // default constructor that initialize all subobjects, so must be empty,
3709 // so this almost never matters.
3710 switch (S->getStmtClass()) {
3711 case Stmt::CompoundStmtClass:
3712 // FIXME: Precompute which substatement of a compound statement we
3713 // would jump to, and go straight there rather than performing a
3714 // linear scan each time.
3715 case Stmt::LabelStmtClass:
3716 case Stmt::AttributedStmtClass:
3717 case Stmt::DoStmtClass:
3718 break;
3719
3720 case Stmt::CaseStmtClass:
3721 case Stmt::DefaultStmtClass:
3722 if (Case == S)
3723 Case = nullptr;
3724 break;
3725
3726 case Stmt::IfStmtClass: {
3727 // FIXME: Precompute which side of an 'if' we would jump to, and go
3728 // straight there rather than scanning both sides.
3729 const IfStmt *IS = cast<IfStmt>(S);
3730
3731 // Wrap the evaluation in a block scope, in case it's a DeclStmt
3732 // preceded by our switch label.
3733 BlockScopeRAII Scope(Info);
3734
3735 EvalStmtResult ESR = EvaluateStmt(Result, Info, IS->getThen(), Case);
3736 if (ESR != ESR_CaseNotFound || !IS->getElse())
3737 return ESR;
3738 return EvaluateStmt(Result, Info, IS->getElse(), Case);
3739 }
3740
3741 case Stmt::WhileStmtClass: {
3742 EvalStmtResult ESR =
3743 EvaluateLoopBody(Result, Info, cast<WhileStmt>(S)->getBody(), Case);
3744 if (ESR != ESR_Continue)
3745 return ESR;
3746 break;
3747 }
3748
3749 case Stmt::ForStmtClass: {
3750 const ForStmt *FS = cast<ForStmt>(S);
3751 EvalStmtResult ESR =
3752 EvaluateLoopBody(Result, Info, FS->getBody(), Case);
3753 if (ESR != ESR_Continue)
3754 return ESR;
3755 if (FS->getInc()) {
3756 FullExpressionRAII IncScope(Info);
3757 if (!EvaluateIgnoredValue(Info, FS->getInc()))
3758 return ESR_Failed;
3759 }
3760 break;
3761 }
3762
3763 case Stmt::DeclStmtClass:
3764 // FIXME: If the variable has initialization that can't be jumped over,
3765 // bail out of any immediately-surrounding compound-statement too.
3766 default:
3767 return ESR_CaseNotFound;
3768 }
3769 }
3770
3771 switch (S->getStmtClass()) {
3772 default:
3773 if (const Expr *E = dyn_cast<Expr>(S)) {
3774 // Don't bother evaluating beyond an expression-statement which couldn't
3775 // be evaluated.
3776 FullExpressionRAII Scope(Info);
3777 if (!EvaluateIgnoredValue(Info, E))
3778 return ESR_Failed;
3779 return ESR_Succeeded;
3780 }
3781
3782 Info.FFDiag(S->getLocStart());
3783 return ESR_Failed;
3784
3785 case Stmt::NullStmtClass:
3786 return ESR_Succeeded;
3787
3788 case Stmt::DeclStmtClass: {
3789 const DeclStmt *DS = cast<DeclStmt>(S);
3790 for (const auto *DclIt : DS->decls()) {
3791 // Each declaration initialization is its own full-expression.
3792 // FIXME: This isn't quite right; if we're performing aggregate
3793 // initialization, each braced subexpression is its own full-expression.
3794 FullExpressionRAII Scope(Info);
3795 if (!EvaluateDecl(Info, DclIt) && !Info.noteFailure())
3796 return ESR_Failed;
3797 }
3798 return ESR_Succeeded;
3799 }
3800
3801 case Stmt::ReturnStmtClass: {
3802 const Expr *RetExpr = cast<ReturnStmt>(S)->getRetValue();
3803 FullExpressionRAII Scope(Info);
3804 if (RetExpr &&
3805 !(Result.Slot
3806 ? EvaluateInPlace(Result.Value, Info, *Result.Slot, RetExpr)
3807 : Evaluate(Result.Value, Info, RetExpr)))
3808 return ESR_Failed;
3809 return ESR_Returned;
3810 }
3811
3812 case Stmt::CompoundStmtClass: {
3813 BlockScopeRAII Scope(Info);
3814
3815 const CompoundStmt *CS = cast<CompoundStmt>(S);
3816 for (const auto *BI : CS->body()) {
3817 EvalStmtResult ESR = EvaluateStmt(Result, Info, BI, Case);
3818 if (ESR == ESR_Succeeded)
3819 Case = nullptr;
3820 else if (ESR != ESR_CaseNotFound)
3821 return ESR;
3822 }
3823 return Case ? ESR_CaseNotFound : ESR_Succeeded;
3824 }
3825
3826 case Stmt::IfStmtClass: {
3827 const IfStmt *IS = cast<IfStmt>(S);
3828
3829 // Evaluate the condition, as either a var decl or as an expression.
3830 BlockScopeRAII Scope(Info);
3831 if (const Stmt *Init = IS->getInit()) {
3832 EvalStmtResult ESR = EvaluateStmt(Result, Info, Init);
3833 if (ESR != ESR_Succeeded)
3834 return ESR;
3835 }
3836 bool Cond;
3837 if (!EvaluateCond(Info, IS->getConditionVariable(), IS->getCond(), Cond))
3838 return ESR_Failed;
3839
3840 if (const Stmt *SubStmt = Cond ? IS->getThen() : IS->getElse()) {
3841 EvalStmtResult ESR = EvaluateStmt(Result, Info, SubStmt);
3842 if (ESR != ESR_Succeeded)
3843 return ESR;
3844 }
3845 return ESR_Succeeded;
3846 }
3847
3848 case Stmt::WhileStmtClass: {
3849 const WhileStmt *WS = cast<WhileStmt>(S);
3850 while (true) {
3851 BlockScopeRAII Scope(Info);
3852 bool Continue;
3853 if (!EvaluateCond(Info, WS->getConditionVariable(), WS->getCond(),
3854 Continue))
3855 return ESR_Failed;
3856 if (!Continue)
3857 break;
3858
3859 EvalStmtResult ESR = EvaluateLoopBody(Result, Info, WS->getBody());
3860 if (ESR != ESR_Continue)
3861 return ESR;
3862 }
3863 return ESR_Succeeded;
3864 }
3865
3866 case Stmt::DoStmtClass: {
3867 const DoStmt *DS = cast<DoStmt>(S);
3868 bool Continue;
3869 do {
3870 EvalStmtResult ESR = EvaluateLoopBody(Result, Info, DS->getBody(), Case);
3871 if (ESR != ESR_Continue)
3872 return ESR;
3873 Case = nullptr;
3874
3875 FullExpressionRAII CondScope(Info);
3876 if (!EvaluateAsBooleanCondition(DS->getCond(), Continue, Info))
3877 return ESR_Failed;
3878 } while (Continue);
3879 return ESR_Succeeded;
3880 }
3881
3882 case Stmt::ForStmtClass: {
3883 const ForStmt *FS = cast<ForStmt>(S);
3884 BlockScopeRAII Scope(Info);
3885 if (FS->getInit()) {
3886 EvalStmtResult ESR = EvaluateStmt(Result, Info, FS->getInit());
3887 if (ESR != ESR_Succeeded)
3888 return ESR;
3889 }
3890 while (true) {
3891 BlockScopeRAII Scope(Info);
3892 bool Continue = true;
3893 if (FS->getCond() && !EvaluateCond(Info, FS->getConditionVariable(),
3894 FS->getCond(), Continue))
3895 return ESR_Failed;
3896 if (!Continue)
3897 break;
3898
3899 EvalStmtResult ESR = EvaluateLoopBody(Result, Info, FS->getBody());
3900 if (ESR != ESR_Continue)
3901 return ESR;
3902
3903 if (FS->getInc()) {
3904 FullExpressionRAII IncScope(Info);
3905 if (!EvaluateIgnoredValue(Info, FS->getInc()))
3906 return ESR_Failed;
3907 }
3908 }
3909 return ESR_Succeeded;
3910 }
3911
3912 case Stmt::CXXForRangeStmtClass: {
3913 const CXXForRangeStmt *FS = cast<CXXForRangeStmt>(S);
3914 BlockScopeRAII Scope(Info);
3915
3916 // Initialize the __range variable.
3917 EvalStmtResult ESR = EvaluateStmt(Result, Info, FS->getRangeStmt());
3918 if (ESR != ESR_Succeeded)
3919 return ESR;
3920
3921 // Create the __begin and __end iterators.
3922 ESR = EvaluateStmt(Result, Info, FS->getBeginStmt());
3923 if (ESR != ESR_Succeeded)
3924 return ESR;
3925 ESR = EvaluateStmt(Result, Info, FS->getEndStmt());
3926 if (ESR != ESR_Succeeded)
3927 return ESR;
3928
3929 while (true) {
3930 // Condition: __begin != __end.
3931 {
3932 bool Continue = true;
3933 FullExpressionRAII CondExpr(Info);
3934 if (!EvaluateAsBooleanCondition(FS->getCond(), Continue, Info))
3935 return ESR_Failed;
3936 if (!Continue)
3937 break;
3938 }
3939
3940 // User's variable declaration, initialized by *__begin.
3941 BlockScopeRAII InnerScope(Info);
3942 ESR = EvaluateStmt(Result, Info, FS->getLoopVarStmt());
3943 if (ESR != ESR_Succeeded)
3944 return ESR;
3945
3946 // Loop body.
3947 ESR = EvaluateLoopBody(Result, Info, FS->getBody());
3948 if (ESR != ESR_Continue)
3949 return ESR;
3950
3951 // Increment: ++__begin
3952 if (!EvaluateIgnoredValue(Info, FS->getInc()))
3953 return ESR_Failed;
3954 }
3955
3956 return ESR_Succeeded;
3957 }
3958
3959 case Stmt::SwitchStmtClass:
3960 return EvaluateSwitch(Result, Info, cast<SwitchStmt>(S));
3961
3962 case Stmt::ContinueStmtClass:
3963 return ESR_Continue;
3964
3965 case Stmt::BreakStmtClass:
3966 return ESR_Break;
3967
3968 case Stmt::LabelStmtClass:
3969 return EvaluateStmt(Result, Info, cast<LabelStmt>(S)->getSubStmt(), Case);
3970
3971 case Stmt::AttributedStmtClass:
3972 // As a general principle, C++11 attributes can be ignored without
3973 // any semantic impact.
3974 return EvaluateStmt(Result, Info, cast<AttributedStmt>(S)->getSubStmt(),
3975 Case);
3976
3977 case Stmt::CaseStmtClass:
3978 case Stmt::DefaultStmtClass:
3979 return EvaluateStmt(Result, Info, cast<SwitchCase>(S)->getSubStmt(), Case);
3980 }
3981}
3982
3983/// CheckTrivialDefaultConstructor - Check whether a constructor is a trivial
3984/// default constructor. If so, we'll fold it whether or not it's marked as
3985/// constexpr. If it is marked as constexpr, we will never implicitly define it,
3986/// so we need special handling.
3987static bool CheckTrivialDefaultConstructor(EvalInfo &Info, SourceLocation Loc,
3988 const CXXConstructorDecl *CD,
3989 bool IsValueInitialization) {
3990 if (!CD->isTrivial() || !CD->isDefaultConstructor())
3991 return false;
3992
3993 // Value-initialization does not call a trivial default constructor, so such a
3994 // call is a core constant expression whether or not the constructor is
3995 // constexpr.
3996 if (!CD->isConstexpr() && !IsValueInitialization) {
3997 if (Info.getLangOpts().CPlusPlus11) {
3998 // FIXME: If DiagDecl is an implicitly-declared special member function,
3999 // we should be much more explicit about why it's not constexpr.
4000 Info.CCEDiag(Loc, diag::note_constexpr_invalid_function, 1)
4001 << /*IsConstexpr*/0 << /*IsConstructor*/1 << CD;
4002 Info.Note(CD->getLocation(), diag::note_declared_at);
4003 } else {
4004 Info.CCEDiag(Loc, diag::note_invalid_subexpr_in_const_expr);
4005 }
4006 }
4007 return true;
4008}
4009
4010/// CheckConstexprFunction - Check that a function can be called in a constant
4011/// expression.
4012static bool CheckConstexprFunction(EvalInfo &Info, SourceLocation CallLoc,
4013 const FunctionDecl *Declaration,
4014 const FunctionDecl *Definition,
4015 const Stmt *Body) {
4016 // Potential constant expressions can contain calls to declared, but not yet
4017 // defined, constexpr functions.
4018 if (Info.checkingPotentialConstantExpression() && !Definition &&
4019 Declaration->isConstexpr())
4020 return false;
4021
4022 // Bail out with no diagnostic if the function declaration itself is invalid.
4023 // We will have produced a relevant diagnostic while parsing it.
4024 if (Declaration->isInvalidDecl())
4025 return false;
4026
4027 // Can we evaluate this function call?
4028 if (Definition && Definition->isConstexpr() &&
4029 !Definition->isInvalidDecl() && Body)
4030 return true;
4031
4032 if (Info.getLangOpts().CPlusPlus11) {
4033 const FunctionDecl *DiagDecl = Definition ? Definition : Declaration;
4034
4035 // If this function is not constexpr because it is an inherited
4036 // non-constexpr constructor, diagnose that directly.
4037 auto *CD = dyn_cast<CXXConstructorDecl>(DiagDecl);
4038 if (CD && CD->isInheritingConstructor()) {
4039 auto *Inherited = CD->getInheritedConstructor().getConstructor();
4040 if (!Inherited->isConstexpr())
4041 DiagDecl = CD = Inherited;
4042 }
4043
4044 // FIXME: If DiagDecl is an implicitly-declared special member function
4045 // or an inheriting constructor, we should be much more explicit about why
4046 // it's not constexpr.
4047 if (CD && CD->isInheritingConstructor())
4048 Info.FFDiag(CallLoc, diag::note_constexpr_invalid_inhctor, 1)
4049 << CD->getInheritedConstructor().getConstructor()->getParent();
4050 else
4051 Info.FFDiag(CallLoc, diag::note_constexpr_invalid_function, 1)
4052 << DiagDecl->isConstexpr() << (bool)CD << DiagDecl;
4053 Info.Note(DiagDecl->getLocation(), diag::note_declared_at);
4054 } else {
4055 Info.FFDiag(CallLoc, diag::note_invalid_subexpr_in_const_expr);
4056 }
4057 return false;
4058}
4059
4060/// Determine if a class has any fields that might need to be copied by a
4061/// trivial copy or move operation.
4062static bool hasFields(const CXXRecordDecl *RD) {
4063 if (!RD || RD->isEmpty())
4064 return false;
4065 for (auto *FD : RD->fields()) {
4066 if (FD->isUnnamedBitfield())
4067 continue;
4068 return true;
4069 }
4070 for (auto &Base : RD->bases())
4071 if (hasFields(Base.getType()->getAsCXXRecordDecl()))
4072 return true;
4073 return false;
4074}
4075
4076namespace {
4077typedef SmallVector<APValue, 8> ArgVector;
4078}
4079
4080/// EvaluateArgs - Evaluate the arguments to a function call.
4081static bool EvaluateArgs(ArrayRef<const Expr*> Args, ArgVector &ArgValues,
4082 EvalInfo &Info) {
4083 bool Success = true;
4084 for (ArrayRef<const Expr*>::iterator I = Args.begin(), E = Args.end();
4085 I != E; ++I) {
4086 if (!Evaluate(ArgValues[I - Args.begin()], Info, *I)) {
4087 // If we're checking for a potential constant expression, evaluate all
4088 // initializers even if some of them fail.
4089 if (!Info.noteFailure())
4090 return false;
4091 Success = false;
4092 }
4093 }
4094 return Success;
4095}
4096
4097/// Evaluate a function call.
4098static bool HandleFunctionCall(SourceLocation CallLoc,
4099 const FunctionDecl *Callee, const LValue *This,
4100 ArrayRef<const Expr*> Args, const Stmt *Body,
4101 EvalInfo &Info, APValue &Result,
4102 const LValue *ResultSlot) {
4103 ArgVector ArgValues(Args.size());
4104 if (!EvaluateArgs(Args, ArgValues, Info))
4105 return false;
4106
4107 if (!Info.CheckCallLimit(CallLoc))
4108 return false;
4109
4110 CallStackFrame Frame(Info, CallLoc, Callee, This, ArgValues.data());
4111
4112 // For a trivial copy or move assignment, perform an APValue copy. This is
4113 // essential for unions, where the operations performed by the assignment
4114 // operator cannot be represented as statements.
4115 //
4116 // Skip this for non-union classes with no fields; in that case, the defaulted
4117 // copy/move does not actually read the object.
4118 const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(Callee);
4119 if (MD && MD->isDefaulted() &&
4120 (MD->getParent()->isUnion() ||
4121 (MD->isTrivial() && hasFields(MD->getParent())))) {
4122 assert(This &&((This && (MD->isCopyAssignmentOperator() || MD->
isMoveAssignmentOperator())) ? static_cast<void> (0) : __assert_fail
("This && (MD->isCopyAssignmentOperator() || MD->isMoveAssignmentOperator())"
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 4123, __PRETTY_FUNCTION__))
4123 (MD->isCopyAssignmentOperator() || MD->isMoveAssignmentOperator()))((This && (MD->isCopyAssignmentOperator() || MD->
isMoveAssignmentOperator())) ? static_cast<void> (0) : __assert_fail
("This && (MD->isCopyAssignmentOperator() || MD->isMoveAssignmentOperator())"
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 4123, __PRETTY_FUNCTION__))
;
4124 LValue RHS;
4125 RHS.setFrom(Info.Ctx, ArgValues[0]);
4126 APValue RHSValue;
4127 if (!handleLValueToRValueConversion(Info, Args[0], Args[0]->getType(),
4128 RHS, RHSValue))
4129 return false;
4130 if (!handleAssignment(Info, Args[0], *This, MD->getThisType(Info.Ctx),
4131 RHSValue))
4132 return false;
4133 This->moveInto(Result);
4134 return true;
4135 }
4136
4137 StmtResult Ret = {Result, ResultSlot};
4138 EvalStmtResult ESR = EvaluateStmt(Ret, Info, Body);
4139 if (ESR == ESR_Succeeded) {
4140 if (Callee->getReturnType()->isVoidType())
4141 return true;
4142 Info.FFDiag(Callee->getLocEnd(), diag::note_constexpr_no_return);
4143 }
4144 return ESR == ESR_Returned;
4145}
4146
4147/// Evaluate a constructor call.
4148static bool HandleConstructorCall(const Expr *E, const LValue &This,
4149 APValue *ArgValues,
4150 const CXXConstructorDecl *Definition,
4151 EvalInfo &Info, APValue &Result) {
4152 SourceLocation CallLoc = E->getExprLoc();
4153 if (!Info.CheckCallLimit(CallLoc))
4154 return false;
4155
4156 const CXXRecordDecl *RD = Definition->getParent();
4157 if (RD->getNumVBases()) {
4158 Info.FFDiag(CallLoc, diag::note_constexpr_virtual_base) << RD;
4159 return false;
4160 }
4161
4162 CallStackFrame Frame(Info, CallLoc, Definition, &This, ArgValues);
4163
4164 // FIXME: Creating an APValue just to hold a nonexistent return value is
4165 // wasteful.
4166 APValue RetVal;
4167 StmtResult Ret = {RetVal, nullptr};
4168
4169 // If it's a delegating constructor, delegate.
4170 if (Definition->isDelegatingConstructor()) {
4171 CXXConstructorDecl::init_const_iterator I = Definition->init_begin();
4172 {
4173 FullExpressionRAII InitScope(Info);
4174 if (!EvaluateInPlace(Result, Info, This, (*I)->getInit()))
4175 return false;
4176 }
4177 return EvaluateStmt(Ret, Info, Definition->getBody()) != ESR_Failed;
4178 }
4179
4180 // For a trivial copy or move constructor, perform an APValue copy. This is
4181 // essential for unions (or classes with anonymous union members), where the
4182 // operations performed by the constructor cannot be represented by
4183 // ctor-initializers.
4184 //
4185 // Skip this for empty non-union classes; we should not perform an
4186 // lvalue-to-rvalue conversion on them because their copy constructor does not
4187 // actually read them.
4188 if (Definition->isDefaulted() && Definition->isCopyOrMoveConstructor() &&
4189 (Definition->getParent()->isUnion() ||
4190 (Definition->isTrivial() && hasFields(Definition->getParent())))) {
4191 LValue RHS;
4192 RHS.setFrom(Info.Ctx, ArgValues[0]);
4193 return handleLValueToRValueConversion(
4194 Info, E, Definition->getParamDecl(0)->getType().getNonReferenceType(),
4195 RHS, Result);
4196 }
4197
4198 // Reserve space for the struct members.
4199 if (!RD->isUnion() && Result.isUninit())
4200 Result = APValue(APValue::UninitStruct(), RD->getNumBases(),
4201 std::distance(RD->field_begin(), RD->field_end()));
4202
4203 if (RD->isInvalidDecl()) return false;
4204 const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(RD);
4205
4206 // A scope for temporaries lifetime-extended by reference members.
4207 BlockScopeRAII LifetimeExtendedScope(Info);
4208
4209 bool Success = true;
4210 unsigned BasesSeen = 0;
4211#ifndef NDEBUG
4212 CXXRecordDecl::base_class_const_iterator BaseIt = RD->bases_begin();
4213#endif
4214 for (const auto *I : Definition->inits()) {
4215 LValue Subobject = This;
4216 APValue *Value = &Result;
4217
4218 // Determine the subobject to initialize.
4219 FieldDecl *FD = nullptr;
4220 if (I->isBaseInitializer()) {
4221 QualType BaseType(I->getBaseClass(), 0);
4222#ifndef NDEBUG
4223 // Non-virtual base classes are initialized in the order in the class
4224 // definition. We have already checked for virtual base classes.
4225 assert(!BaseIt->isVirtual() && "virtual base for literal type")((!BaseIt->isVirtual() && "virtual base for literal type"
) ? static_cast<void> (0) : __assert_fail ("!BaseIt->isVirtual() && \"virtual base for literal type\""
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 4225, __PRETTY_FUNCTION__))
;
4226 assert(Info.Ctx.hasSameType(BaseIt->getType(), BaseType) &&((Info.Ctx.hasSameType(BaseIt->getType(), BaseType) &&
"base class initializers not in expected order") ? static_cast
<void> (0) : __assert_fail ("Info.Ctx.hasSameType(BaseIt->getType(), BaseType) && \"base class initializers not in expected order\""
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 4227, __PRETTY_FUNCTION__))
4227 "base class initializers not in expected order")((Info.Ctx.hasSameType(BaseIt->getType(), BaseType) &&
"base class initializers not in expected order") ? static_cast
<void> (0) : __assert_fail ("Info.Ctx.hasSameType(BaseIt->getType(), BaseType) && \"base class initializers not in expected order\""
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 4227, __PRETTY_FUNCTION__))
;
4228 ++BaseIt;
4229#endif
4230 if (!HandleLValueDirectBase(Info, I->getInit(), Subobject, RD,
4231 BaseType->getAsCXXRecordDecl(), &Layout))
4232 return false;
4233 Value = &Result.getStructBase(BasesSeen++);
4234 } else if ((FD = I->getMember())) {
4235 if (!HandleLValueMember(Info, I->getInit(), Subobject, FD, &Layout))
4236 return false;
4237 if (RD->isUnion()) {
4238 Result = APValue(FD);
4239 Value = &Result.getUnionValue();
4240 } else {
4241 Value = &Result.getStructField(FD->getFieldIndex());
4242 }
4243 } else if (IndirectFieldDecl *IFD = I->getIndirectMember()) {
4244 // Walk the indirect field decl's chain to find the object to initialize,
4245 // and make sure we've initialized every step along it.
4246 for (auto *C : IFD->chain()) {
4247 FD = cast<FieldDecl>(C);
4248 CXXRecordDecl *CD = cast<CXXRecordDecl>(FD->getParent());
4249 // Switch the union field if it differs. This happens if we had
4250 // preceding zero-initialization, and we're now initializing a union
4251 // subobject other than the first.
4252 // FIXME: In this case, the values of the other subobjects are
4253 // specified, since zero-initialization sets all padding bits to zero.
4254 if (Value->isUninit() ||
4255 (Value->isUnion() && Value->getUnionField() != FD)) {
4256 if (CD->isUnion())
4257 *Value = APValue(FD);
4258 else
4259 *Value = APValue(APValue::UninitStruct(), CD->getNumBases(),
4260 std::distance(CD->field_begin(), CD->field_end()));
4261 }
4262 if (!HandleLValueMember(Info, I->getInit(), Subobject, FD))
4263 return false;
4264 if (CD->isUnion())
4265 Value = &Value->getUnionValue();
4266 else
4267 Value = &Value->getStructField(FD->getFieldIndex());
4268 }
4269 } else {
4270 llvm_unreachable("unknown base initializer kind")::llvm::llvm_unreachable_internal("unknown base initializer kind"
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 4270)
;
4271 }
4272
4273 FullExpressionRAII InitScope(Info);
4274 if (!EvaluateInPlace(*Value, Info, Subobject, I->getInit()) ||
4275 (FD && FD->isBitField() && !truncateBitfieldValue(Info, I->getInit(),
4276 *Value, FD))) {
4277 // If we're checking for a potential constant expression, evaluate all
4278 // initializers even if some of them fail.
4279 if (!Info.noteFailure())
4280 return false;
4281 Success = false;
4282 }
4283 }
4284
4285 return Success &&
4286 EvaluateStmt(Ret, Info, Definition->getBody()) != ESR_Failed;
4287}
4288
4289static bool HandleConstructorCall(const Expr *E, const LValue &This,
4290 ArrayRef<const Expr*> Args,
4291 const CXXConstructorDecl *Definition,
4292 EvalInfo &Info, APValue &Result) {
4293 ArgVector ArgValues(Args.size());
4294 if (!EvaluateArgs(Args, ArgValues, Info))
4295 return false;
4296
4297 return HandleConstructorCall(E, This, ArgValues.data(), Definition,
4298 Info, Result);
4299}
4300
4301//===----------------------------------------------------------------------===//
4302// Generic Evaluation
4303//===----------------------------------------------------------------------===//
4304namespace {
4305
4306template <class Derived>
4307class ExprEvaluatorBase
4308 : public ConstStmtVisitor<Derived, bool> {
4309private:
4310 Derived &getDerived() { return static_cast<Derived&>(*this); }
4311 bool DerivedSuccess(const APValue &V, const Expr *E) {
4312 return getDerived().Success(V, E);
4313 }
4314 bool DerivedZeroInitialization(const Expr *E) {
4315 return getDerived().ZeroInitialization(E);
4316 }
4317
4318 // Check whether a conditional operator with a non-constant condition is a
4319 // potential constant expression. If neither arm is a potential constant
4320 // expression, then the conditional operator is not either.
4321 template<typename ConditionalOperator>
4322 void CheckPotentialConstantConditional(const ConditionalOperator *E) {
4323 assert(Info.checkingPotentialConstantExpression())((Info.checkingPotentialConstantExpression()) ? static_cast<
void> (0) : __assert_fail ("Info.checkingPotentialConstantExpression()"
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 4323, __PRETTY_FUNCTION__))
;
4324
4325 // Speculatively evaluate both arms.
4326 SmallVector<PartialDiagnosticAt, 8> Diag;
4327 {
4328 SpeculativeEvaluationRAII Speculate(Info, &Diag);
4329 StmtVisitorTy::Visit(E->getFalseExpr());
4330 if (Diag.empty())
4331 return;
4332 }
4333
4334 {
4335 SpeculativeEvaluationRAII Speculate(Info, &Diag);
4336 Diag.clear();
4337 StmtVisitorTy::Visit(E->getTrueExpr());
4338 if (Diag.empty())
4339 return;
4340 }
4341
4342 Error(E, diag::note_constexpr_conditional_never_const);
4343 }
4344
4345
4346 template<typename ConditionalOperator>
4347 bool HandleConditionalOperator(const ConditionalOperator *E) {
4348 bool BoolResult;
4349 if (!EvaluateAsBooleanCondition(E->getCond(), BoolResult, Info)) {
4350 if (Info.checkingPotentialConstantExpression() && Info.noteFailure())
4351 CheckPotentialConstantConditional(E);
4352 return false;
4353 }
4354
4355 Expr *EvalExpr = BoolResult ? E->getTrueExpr() : E->getFalseExpr();
4356 return StmtVisitorTy::Visit(EvalExpr);
4357 }
4358
4359protected:
4360 EvalInfo &Info;
4361 typedef ConstStmtVisitor<Derived, bool> StmtVisitorTy;
4362 typedef ExprEvaluatorBase ExprEvaluatorBaseTy;
4363
4364 OptionalDiagnostic CCEDiag(const Expr *E, diag::kind D) {
4365 return Info.CCEDiag(E, D);
4366 }
4367
4368 bool ZeroInitialization(const Expr *E) { return Error(E); }
4369
4370public:
4371 ExprEvaluatorBase(EvalInfo &Info) : Info(Info) {}
4372
4373 EvalInfo &getEvalInfo() { return Info; }
4374
4375 /// Report an evaluation error. This should only be called when an error is
4376 /// first discovered. When propagating an error, just return false.
4377 bool Error(const Expr *E, diag::kind D) {
4378 Info.FFDiag(E, D);
4379 return false;
4380 }
4381 bool Error(const Expr *E) {
4382 return Error(E, diag::note_invalid_subexpr_in_const_expr);
4383 }
4384
4385 bool VisitStmt(const Stmt *) {
4386 llvm_unreachable("Expression evaluator should not be called on stmts")::llvm::llvm_unreachable_internal("Expression evaluator should not be called on stmts"
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 4386)
;
4387 }
4388 bool VisitExpr(const Expr *E) {
4389 return Error(E);
4390 }
4391
4392 bool VisitParenExpr(const ParenExpr *E)
4393 { return StmtVisitorTy::Visit(E->getSubExpr()); }
4394 bool VisitUnaryExtension(const UnaryOperator *E)
4395 { return StmtVisitorTy::Visit(E->getSubExpr()); }
4396 bool VisitUnaryPlus(const UnaryOperator *E)
4397 { return StmtVisitorTy::Visit(E->getSubExpr()); }
4398 bool VisitChooseExpr(const ChooseExpr *E)
4399 { return StmtVisitorTy::Visit(E->getChosenSubExpr()); }
4400 bool VisitGenericSelectionExpr(const GenericSelectionExpr *E)
4401 { return StmtVisitorTy::Visit(E->getResultExpr()); }
4402 bool VisitSubstNonTypeTemplateParmExpr(const SubstNonTypeTemplateParmExpr *E)
4403 { return StmtVisitorTy::Visit(E->getReplacement()); }
4404 bool VisitCXXDefaultArgExpr(const CXXDefaultArgExpr *E)
4405 { return StmtVisitorTy::Visit(E->getExpr()); }
4406 bool VisitCXXDefaultInitExpr(const CXXDefaultInitExpr *E) {
4407 // The initializer may not have been parsed yet, or might be erroneous.
4408 if (!E->getExpr())
4409 return Error(E);
4410 return StmtVisitorTy::Visit(E->getExpr());
4411 }
4412 // We cannot create any objects for which cleanups are required, so there is
4413 // nothing to do here; all cleanups must come from unevaluated subexpressions.
4414 bool VisitExprWithCleanups(const ExprWithCleanups *E)
4415 { return StmtVisitorTy::Visit(E->getSubExpr()); }
4416
4417 bool VisitCXXReinterpretCastExpr(const CXXReinterpretCastExpr *E) {
4418 CCEDiag(E, diag::note_constexpr_invalid_cast) << 0;
4419 return static_cast<Derived*>(this)->VisitCastExpr(E);
4420 }
4421 bool VisitCXXDynamicCastExpr(const CXXDynamicCastExpr *E) {
4422 CCEDiag(E, diag::note_constexpr_invalid_cast) << 1;
4423 return static_cast<Derived*>(this)->VisitCastExpr(E);
4424 }
4425
4426 bool VisitBinaryOperator(const BinaryOperator *E) {
4427 switch (E->getOpcode()) {
4428 default:
4429 return Error(E);
4430
4431 case BO_Comma:
4432 VisitIgnoredValue(E->getLHS());
4433 return StmtVisitorTy::Visit(E->getRHS());
4434
4435 case BO_PtrMemD:
4436 case BO_PtrMemI: {
4437 LValue Obj;
4438 if (!HandleMemberPointerAccess(Info, E, Obj))
4439 return false;
4440 APValue Result;
4441 if (!handleLValueToRValueConversion(Info, E, E->getType(), Obj, Result))
4442 return false;
4443 return DerivedSuccess(Result, E);
4444 }
4445 }
4446 }
4447
4448 bool VisitBinaryConditionalOperator(const BinaryConditionalOperator *E) {
4449 // Evaluate and cache the common expression. We treat it as a temporary,
4450 // even though it's not quite the same thing.
4451 if (!Evaluate(Info.CurrentCall->createTemporary(E->getOpaqueValue(), false),
4452 Info, E->getCommon()))
4453 return false;
4454
4455 return HandleConditionalOperator(E);
4456 }
4457
4458 bool VisitConditionalOperator(const ConditionalOperator *E) {
4459 bool IsBcpCall = false;
4460 // If the condition (ignoring parens) is a __builtin_constant_p call,
4461 // the result is a constant expression if it can be folded without
4462 // side-effects. This is an important GNU extension. See GCC PR38377
4463 // for discussion.
4464 if (const CallExpr *CallCE =
4465 dyn_cast<CallExpr>(E->getCond()->IgnoreParenCasts()))
4466 if (CallCE->getBuiltinCallee() == Builtin::BI__builtin_constant_p)
4467 IsBcpCall = true;
4468
4469 // Always assume __builtin_constant_p(...) ? ... : ... is a potential
4470 // constant expression; we can't check whether it's potentially foldable.
4471 if (Info.checkingPotentialConstantExpression() && IsBcpCall)
4472 return false;
4473
4474 FoldConstant Fold(Info, IsBcpCall);
4475 if (!HandleConditionalOperator(E)) {
4476 Fold.keepDiagnostics();
4477 return false;
4478 }
4479
4480 return true;
4481 }
4482
4483 bool VisitOpaqueValueExpr(const OpaqueValueExpr *E) {
4484 if (APValue *Value = Info.CurrentCall->getTemporary(E))
4485 return DerivedSuccess(*Value, E);
4486
4487 const Expr *Source = E->getSourceExpr();
4488 if (!Source)
4489 return Error(E);
4490 if (Source == E) { // sanity checking.
4491 assert(0 && "OpaqueValueExpr recursively refers to itself")((0 && "OpaqueValueExpr recursively refers to itself"
) ? static_cast<void> (0) : __assert_fail ("0 && \"OpaqueValueExpr recursively refers to itself\""
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 4491, __PRETTY_FUNCTION__))
;
4492 return Error(E);
4493 }
4494 return StmtVisitorTy::Visit(Source);
4495 }
4496
4497 bool VisitCallExpr(const CallExpr *E) {
4498 APValue Result;
4499 if (!handleCallExpr(E, Result, nullptr))
4500 return false;
4501 return DerivedSuccess(Result, E);
4502 }
4503
4504 bool handleCallExpr(const CallExpr *E, APValue &Result,
4505 const LValue *ResultSlot) {
4506 const Expr *Callee = E->getCallee()->IgnoreParens();
4507 QualType CalleeType = Callee->getType();
4508
4509 const FunctionDecl *FD = nullptr;
4510 LValue *This = nullptr, ThisVal;
4511 auto Args = llvm::makeArrayRef(E->getArgs(), E->getNumArgs());
4512 bool HasQualifier = false;
4513
4514 // Extract function decl and 'this' pointer from the callee.
4515 if (CalleeType->isSpecificBuiltinType(BuiltinType::BoundMember)) {
4516 const ValueDecl *Member = nullptr;
4517 if (const MemberExpr *ME = dyn_cast<MemberExpr>(Callee)) {
4518 // Explicit bound member calls, such as x.f() or p->g();
4519 if (!EvaluateObjectArgument(Info, ME->getBase(), ThisVal))
4520 return false;
4521 Member = ME->getMemberDecl();
4522 This = &ThisVal;
4523 HasQualifier = ME->hasQualifier();
4524 } else if (const BinaryOperator *BE = dyn_cast<BinaryOperator>(Callee)) {
4525 // Indirect bound member calls ('.*' or '->*').
4526 Member = HandleMemberPointerAccess(Info, BE, ThisVal, false);
4527 if (!Member) return false;
4528 This = &ThisVal;
4529 } else
4530 return Error(Callee);
4531
4532 FD = dyn_cast<FunctionDecl>(Member);
4533 if (!FD)
4534 return Error(Callee);
4535 } else if (CalleeType->isFunctionPointerType()) {
4536 LValue Call;
4537 if (!EvaluatePointer(Callee, Call, Info))
4538 return false;
4539
4540 if (!Call.getLValueOffset().isZero())
4541 return Error(Callee);
4542 FD = dyn_cast_or_null<FunctionDecl>(
4543 Call.getLValueBase().dyn_cast<const ValueDecl*>());
4544 if (!FD)
4545 return Error(Callee);
4546
4547 // Overloaded operator calls to member functions are represented as normal
4548 // calls with '*this' as the first argument.
4549 const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(FD);
4550 if (MD && !MD->isStatic()) {
4551 // FIXME: When selecting an implicit conversion for an overloaded
4552 // operator delete, we sometimes try to evaluate calls to conversion
4553 // operators without a 'this' parameter!
4554 if (Args.empty())
4555 return Error(E);
4556
4557 if (!EvaluateObjectArgument(Info, Args[0], ThisVal))
4558 return false;
4559 This = &ThisVal;
4560 Args = Args.slice(1);
4561 }
4562
4563 // Don't call function pointers which have been cast to some other type.
4564 // Per DR (no number yet), the caller and callee can differ in noexcept.
4565 if (!Info.Ctx.hasSameFunctionTypeIgnoringExceptionSpec(
4566 CalleeType->getPointeeType(), FD->getType())) {
4567 return Error(E);
4568 }
4569 } else
4570 return Error(E);
4571
4572 if (This && !This->checkSubobject(Info, E, CSK_This))
4573 return false;
4574
4575 // DR1358 allows virtual constexpr functions in some cases. Don't allow
4576 // calls to such functions in constant expressions.
4577 if (This && !HasQualifier &&
4578 isa<CXXMethodDecl>(FD) && cast<CXXMethodDecl>(FD)->isVirtual())
4579 return Error(E, diag::note_constexpr_virtual_call);
4580
4581 const FunctionDecl *Definition = nullptr;
4582 Stmt *Body = FD->getBody(Definition);
4583
4584 if (!CheckConstexprFunction(Info, E->getExprLoc(), FD, Definition, Body) ||
4585 !HandleFunctionCall(E->getExprLoc(), Definition, This, Args, Body, Info,
4586 Result, ResultSlot))
4587 return false;
4588
4589 return true;
4590 }
4591
4592 bool VisitCompoundLiteralExpr(const CompoundLiteralExpr *E) {
4593 return StmtVisitorTy::Visit(E->getInitializer());
4594 }
4595 bool VisitInitListExpr(const InitListExpr *E) {
4596 if (E->getNumInits() == 0)
4597 return DerivedZeroInitialization(E);
4598 if (E->getNumInits() == 1)
4599 return StmtVisitorTy::Visit(E->getInit(0));
4600 return Error(E);
4601 }
4602 bool VisitImplicitValueInitExpr(const ImplicitValueInitExpr *E) {
4603 return DerivedZeroInitialization(E);
4604 }
4605 bool VisitCXXScalarValueInitExpr(const CXXScalarValueInitExpr *E) {
4606 return DerivedZeroInitialization(E);
4607 }
4608 bool VisitCXXNullPtrLiteralExpr(const CXXNullPtrLiteralExpr *E) {
4609 return DerivedZeroInitialization(E);
4610 }
4611
4612 /// A member expression where the object is a prvalue is itself a prvalue.
4613 bool VisitMemberExpr(const MemberExpr *E) {
4614 assert(!E->isArrow() && "missing call to bound member function?")((!E->isArrow() && "missing call to bound member function?"
) ? static_cast<void> (0) : __assert_fail ("!E->isArrow() && \"missing call to bound member function?\""
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 4614, __PRETTY_FUNCTION__))
;
4615
4616 APValue Val;
4617 if (!Evaluate(Val, Info, E->getBase()))
4618 return false;
4619
4620 QualType BaseTy = E->getBase()->getType();
4621
4622 const FieldDecl *FD = dyn_cast<FieldDecl>(E->getMemberDecl());
4623 if (!FD) return Error(E);
4624 assert(!FD->getType()->isReferenceType() && "prvalue reference?")((!FD->getType()->isReferenceType() && "prvalue reference?"
) ? static_cast<void> (0) : __assert_fail ("!FD->getType()->isReferenceType() && \"prvalue reference?\""
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 4624, __PRETTY_FUNCTION__))
;
4625 assert(BaseTy->castAs<RecordType>()->getDecl()->getCanonicalDecl() ==((BaseTy->castAs<RecordType>()->getDecl()->getCanonicalDecl
() == FD->getParent()->getCanonicalDecl() && "record / field mismatch"
) ? static_cast<void> (0) : __assert_fail ("BaseTy->castAs<RecordType>()->getDecl()->getCanonicalDecl() == FD->getParent()->getCanonicalDecl() && \"record / field mismatch\""
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 4626, __PRETTY_FUNCTION__))
4626 FD->getParent()->getCanonicalDecl() && "record / field mismatch")((BaseTy->castAs<RecordType>()->getDecl()->getCanonicalDecl
() == FD->getParent()->getCanonicalDecl() && "record / field mismatch"
) ? static_cast<void> (0) : __assert_fail ("BaseTy->castAs<RecordType>()->getDecl()->getCanonicalDecl() == FD->getParent()->getCanonicalDecl() && \"record / field mismatch\""
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 4626, __PRETTY_FUNCTION__))
;
4627
4628 CompleteObject Obj(&Val, BaseTy);
4629 SubobjectDesignator Designator(BaseTy);
4630 Designator.addDeclUnchecked(FD);
4631
4632 APValue Result;
4633 return extractSubobject(Info, E, Obj, Designator, Result) &&
4634 DerivedSuccess(Result, E);
4635 }
4636
4637 bool VisitCastExpr(const CastExpr *E) {
4638 switch (E->getCastKind()) {
4639 default:
4640 break;
4641
4642 case CK_AtomicToNonAtomic: {
4643 APValue AtomicVal;
4644 if (!EvaluateAtomic(E->getSubExpr(), AtomicVal, Info))
4645 return false;
4646 return DerivedSuccess(AtomicVal, E);
4647 }
4648
4649 case CK_NoOp:
4650 case CK_UserDefinedConversion:
4651 return StmtVisitorTy::Visit(E->getSubExpr());
4652
4653 case CK_LValueToRValue: {
4654 LValue LVal;
4655 if (!EvaluateLValue(E->getSubExpr(), LVal, Info))
4656 return false;
4657 APValue RVal;
4658 // Note, we use the subexpression's type in order to retain cv-qualifiers.
4659 if (!handleLValueToRValueConversion(Info, E, E->getSubExpr()->getType(),
4660 LVal, RVal))
4661 return false;
4662 return DerivedSuccess(RVal, E);
4663 }
4664 }
4665
4666 return Error(E);
4667 }
4668
4669 bool VisitUnaryPostInc(const UnaryOperator *UO) {
4670 return VisitUnaryPostIncDec(UO);
4671 }
4672 bool VisitUnaryPostDec(const UnaryOperator *UO) {
4673 return VisitUnaryPostIncDec(UO);
4674 }
4675 bool VisitUnaryPostIncDec(const UnaryOperator *UO) {
4676 if (!Info.getLangOpts().CPlusPlus14 && !Info.keepEvaluatingAfterFailure())
4677 return Error(UO);
4678
4679 LValue LVal;
4680 if (!EvaluateLValue(UO->getSubExpr(), LVal, Info))
4681 return false;
4682 APValue RVal;
4683 if (!handleIncDec(this->Info, UO, LVal, UO->getSubExpr()->getType(),
4684 UO->isIncrementOp(), &RVal))
4685 return false;
4686 return DerivedSuccess(RVal, UO);
4687 }
4688
4689 bool VisitStmtExpr(const StmtExpr *E) {
4690 // We will have checked the full-expressions inside the statement expression
4691 // when they were completed, and don't need to check them again now.
4692 if (Info.checkingForOverflow())
4693 return Error(E);
4694
4695 BlockScopeRAII Scope(Info);
4696 const CompoundStmt *CS = E->getSubStmt();
4697 if (CS->body_empty())
4698 return true;
4699
4700 for (CompoundStmt::const_body_iterator BI = CS->body_begin(),
4701 BE = CS->body_end();
4702 /**/; ++BI) {
4703 if (BI + 1 == BE) {
4704 const Expr *FinalExpr = dyn_cast<Expr>(*BI);
4705 if (!FinalExpr) {
4706 Info.FFDiag((*BI)->getLocStart(),
4707 diag::note_constexpr_stmt_expr_unsupported);
4708 return false;
4709 }
4710 return this->Visit(FinalExpr);
4711 }
4712
4713 APValue ReturnValue;
4714 StmtResult Result = { ReturnValue, nullptr };
4715 EvalStmtResult ESR = EvaluateStmt(Result, Info, *BI);
4716 if (ESR != ESR_Succeeded) {
4717 // FIXME: If the statement-expression terminated due to 'return',
4718 // 'break', or 'continue', it would be nice to propagate that to
4719 // the outer statement evaluation rather than bailing out.
4720 if (ESR != ESR_Failed)
4721 Info.FFDiag((*BI)->getLocStart(),
4722 diag::note_constexpr_stmt_expr_unsupported);
4723 return false;
4724 }
4725 }
4726
4727 llvm_unreachable("Return from function from the loop above.")::llvm::llvm_unreachable_internal("Return from function from the loop above."
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 4727)
;
4728 }
4729
4730 /// Visit a value which is evaluated, but whose value is ignored.
4731 void VisitIgnoredValue(const Expr *E) {
4732 EvaluateIgnoredValue(Info, E);
4733 }
4734
4735 /// Potentially visit a MemberExpr's base expression.
4736 void VisitIgnoredBaseExpression(const Expr *E) {
4737 // While MSVC doesn't evaluate the base expression, it does diagnose the
4738 // presence of side-effecting behavior.
4739 if (Info.getLangOpts().MSVCCompat && !E->HasSideEffects(Info.Ctx))
4740 return;
4741 VisitIgnoredValue(E);
4742 }
4743};
4744
4745}
4746
4747//===----------------------------------------------------------------------===//
4748// Common base class for lvalue and temporary evaluation.
4749//===----------------------------------------------------------------------===//
4750namespace {
4751template<class Derived>
4752class LValueExprEvaluatorBase
4753 : public ExprEvaluatorBase<Derived> {
4754protected:
4755 LValue &Result;
4756 typedef LValueExprEvaluatorBase LValueExprEvaluatorBaseTy;
4757 typedef ExprEvaluatorBase<Derived> ExprEvaluatorBaseTy;
4758
4759 bool Success(APValue::LValueBase B) {
4760 Result.set(B);
4761 return true;
4762 }
4763
4764public:
4765 LValueExprEvaluatorBase(EvalInfo &Info, LValue &Result) :
4766 ExprEvaluatorBaseTy(Info), Result(Result) {}
4767
4768 bool Success(const APValue &V, const Expr *E) {
4769 Result.setFrom(this->Info.Ctx, V);
4770 return true;
4771 }
4772
4773 bool VisitMemberExpr(const MemberExpr *E) {
4774 // Handle non-static data members.
4775 QualType BaseTy;
4776 bool EvalOK;
4777 if (E->isArrow()) {
4778 EvalOK = EvaluatePointer(E->getBase(), Result, this->Info);
4779 BaseTy = E->getBase()->getType()->castAs<PointerType>()->getPointeeType();
4780 } else if (E->getBase()->isRValue()) {
4781 assert(E->getBase()->getType()->isRecordType())((E->getBase()->getType()->isRecordType()) ? static_cast
<void> (0) : __assert_fail ("E->getBase()->getType()->isRecordType()"
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 4781, __PRETTY_FUNCTION__))
;
4782 EvalOK = EvaluateTemporary(E->getBase(), Result, this->Info);
4783 BaseTy = E->getBase()->getType();
4784 } else {
4785 EvalOK = this->Visit(E->getBase());
4786 BaseTy = E->getBase()->getType();
4787 }
4788 if (!EvalOK) {
4789 if (!this->Info.allowInvalidBaseExpr())
4790 return false;
4791 Result.setInvalid(E);
4792 return true;
4793 }
4794
4795 const ValueDecl *MD = E->getMemberDecl();
4796 if (const FieldDecl *FD = dyn_cast<FieldDecl>(E->getMemberDecl())) {
4797 assert(BaseTy->getAs<RecordType>()->getDecl()->getCanonicalDecl() ==((BaseTy->getAs<RecordType>()->getDecl()->getCanonicalDecl
() == FD->getParent()->getCanonicalDecl() && "record / field mismatch"
) ? static_cast<void> (0) : __assert_fail ("BaseTy->getAs<RecordType>()->getDecl()->getCanonicalDecl() == FD->getParent()->getCanonicalDecl() && \"record / field mismatch\""
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 4798, __PRETTY_FUNCTION__))
4798 FD->getParent()->getCanonicalDecl() && "record / field mismatch")((BaseTy->getAs<RecordType>()->getDecl()->getCanonicalDecl
() == FD->getParent()->getCanonicalDecl() && "record / field mismatch"
) ? static_cast<void> (0) : __assert_fail ("BaseTy->getAs<RecordType>()->getDecl()->getCanonicalDecl() == FD->getParent()->getCanonicalDecl() && \"record / field mismatch\""
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 4798, __PRETTY_FUNCTION__))
;
4799 (void)BaseTy;
4800 if (!HandleLValueMember(this->Info, E, Result, FD))
4801 return false;
4802 } else if (const IndirectFieldDecl *IFD = dyn_cast<IndirectFieldDecl>(MD)) {
4803 if (!HandleLValueIndirectMember(this->Info, E, Result, IFD))
4804 return false;
4805 } else
4806 return this->Error(E);
4807
4808 if (MD->getType()->isReferenceType()) {
4809 APValue RefValue;
4810 if (!handleLValueToRValueConversion(this->Info, E, MD->getType(), Result,
4811 RefValue))
4812 return false;
4813 return Success(RefValue, E);
4814 }
4815 return true;
4816 }
4817
4818 bool VisitBinaryOperator(const BinaryOperator *E) {
4819 switch (E->getOpcode()) {
4820 default:
4821 return ExprEvaluatorBaseTy::VisitBinaryOperator(E);
4822
4823 case BO_PtrMemD:
4824 case BO_PtrMemI:
4825 return HandleMemberPointerAccess(this->Info, E, Result);
4826 }
4827 }
4828
4829 bool VisitCastExpr(const CastExpr *E) {
4830 switch (E->getCastKind()) {
4831 default:
4832 return ExprEvaluatorBaseTy::VisitCastExpr(E);
4833
4834 case CK_DerivedToBase:
4835 case CK_UncheckedDerivedToBase:
4836 if (!this->Visit(E->getSubExpr()))
4837 return false;
4838
4839 // Now figure out the necessary offset to add to the base LV to get from
4840 // the derived class to the base class.
4841 return HandleLValueBasePath(this->Info, E, E->getSubExpr()->getType(),
4842 Result);
4843 }
4844 }
4845};
4846}
4847
4848//===----------------------------------------------------------------------===//
4849// LValue Evaluation
4850//
4851// This is used for evaluating lvalues (in C and C++), xvalues (in C++11),
4852// function designators (in C), decl references to void objects (in C), and
4853// temporaries (if building with -Wno-address-of-temporary).
4854//
4855// LValue evaluation produces values comprising a base expression of one of the
4856// following types:
4857// - Declarations
4858// * VarDecl
4859// * FunctionDecl
4860// - Literals
4861// * CompoundLiteralExpr in C (and in global scope in C++)
4862// * StringLiteral
4863// * CXXTypeidExpr
4864// * PredefinedExpr
4865// * ObjCStringLiteralExpr
4866// * ObjCEncodeExpr
4867// * AddrLabelExpr
4868// * BlockExpr
4869// * CallExpr for a MakeStringConstant builtin
4870// - Locals and temporaries
4871// * MaterializeTemporaryExpr
4872// * Any Expr, with a CallIndex indicating the function in which the temporary
4873// was evaluated, for cases where the MaterializeTemporaryExpr is missing
4874// from the AST (FIXME).
4875// * A MaterializeTemporaryExpr that has static storage duration, with no
4876// CallIndex, for a lifetime-extended temporary.
4877// plus an offset in bytes.
4878//===----------------------------------------------------------------------===//
4879namespace {
4880class LValueExprEvaluator
4881 : public LValueExprEvaluatorBase<LValueExprEvaluator> {
4882public:
4883 LValueExprEvaluator(EvalInfo &Info, LValue &Result) :
4884 LValueExprEvaluatorBaseTy(Info, Result) {}
4885
4886 bool VisitVarDecl(const Expr *E, const VarDecl *VD);
4887 bool VisitUnaryPreIncDec(const UnaryOperator *UO);
4888
4889 bool VisitDeclRefExpr(const DeclRefExpr *E);
4890 bool VisitPredefinedExpr(const PredefinedExpr *E) { return Success(E); }
4891 bool VisitMaterializeTemporaryExpr(const MaterializeTemporaryExpr *E);
4892 bool VisitCompoundLiteralExpr(const CompoundLiteralExpr *E);
4893 bool VisitMemberExpr(const MemberExpr *E);
4894 bool VisitStringLiteral(const StringLiteral *E) { return Success(E); }
4895 bool VisitObjCEncodeExpr(const ObjCEncodeExpr *E) { return Success(E); }
4896 bool VisitCXXTypeidExpr(const CXXTypeidExpr *E);
4897 bool VisitCXXUuidofExpr(const CXXUuidofExpr *E);
4898 bool VisitArraySubscriptExpr(const ArraySubscriptExpr *E);
4899 bool VisitUnaryDeref(const UnaryOperator *E);
4900 bool VisitUnaryReal(const UnaryOperator *E);
4901 bool VisitUnaryImag(const UnaryOperator *E);
4902 bool VisitUnaryPreInc(const UnaryOperator *UO) {
4903 return VisitUnaryPreIncDec(UO);
4904 }
4905 bool VisitUnaryPreDec(const UnaryOperator *UO) {
4906 return VisitUnaryPreIncDec(UO);
4907 }
4908 bool VisitBinAssign(const BinaryOperator *BO);
4909 bool VisitCompoundAssignOperator(const CompoundAssignOperator *CAO);
4910
4911 bool VisitCastExpr(const CastExpr *E) {
4912 switch (E->getCastKind()) {
4913 default:
4914 return LValueExprEvaluatorBaseTy::VisitCastExpr(E);
4915
4916 case CK_LValueBitCast:
4917 this->CCEDiag(E, diag::note_constexpr_invalid_cast) << 2;
4918 if (!Visit(E->getSubExpr()))
4919 return false;
4920 Result.Designator.setInvalid();
4921 return true;
4922
4923 case CK_BaseToDerived:
4924 if (!Visit(E->getSubExpr()))
4925 return false;
4926 return HandleBaseToDerivedCast(Info, E, Result);
4927 }
4928 }
4929};
4930} // end anonymous namespace
4931
4932/// Evaluate an expression as an lvalue. This can be legitimately called on
4933/// expressions which are not glvalues, in three cases:
4934/// * function designators in C, and
4935/// * "extern void" objects
4936/// * @selector() expressions in Objective-C
4937static bool EvaluateLValue(const Expr *E, LValue &Result, EvalInfo &Info) {
4938 assert(E->isGLValue() || E->getType()->isFunctionType() ||((E->isGLValue() || E->getType()->isFunctionType() ||
E->getType()->isVoidType() || isa<ObjCSelectorExpr>
(E)) ? static_cast<void> (0) : __assert_fail ("E->isGLValue() || E->getType()->isFunctionType() || E->getType()->isVoidType() || isa<ObjCSelectorExpr>(E)"
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 4939, __PRETTY_FUNCTION__))
4939 E->getType()->isVoidType() || isa<ObjCSelectorExpr>(E))((E->isGLValue() || E->getType()->isFunctionType() ||
E->getType()->isVoidType() || isa<ObjCSelectorExpr>
(E)) ? static_cast<void> (0) : __assert_fail ("E->isGLValue() || E->getType()->isFunctionType() || E->getType()->isVoidType() || isa<ObjCSelectorExpr>(E)"
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 4939, __PRETTY_FUNCTION__))
;
4940 return LValueExprEvaluator(Info, Result).Visit(E);
4941}
4942
4943bool LValueExprEvaluator::VisitDeclRefExpr(const DeclRefExpr *E) {
4944 if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(E->getDecl()))
4945 return Success(FD);
4946 if (const VarDecl *VD = dyn_cast<VarDecl>(E->getDecl()))
4947 return VisitVarDecl(E, VD);
4948 if (const BindingDecl *BD = dyn_cast<BindingDecl>(E->getDecl()))
4949 return Visit(BD->getBinding());
4950 return Error(E);
4951}
4952
4953
4954bool LValueExprEvaluator::VisitVarDecl(const Expr *E, const VarDecl *VD) {
4955 CallStackFrame *Frame = nullptr;
4956 if (VD->hasLocalStorage() && Info.CurrentCall->Index > 1) {
4957 // Only if a local variable was declared in the function currently being
4958 // evaluated, do we expect to be able to find its value in the current
4959 // frame. (Otherwise it was likely declared in an enclosing context and
4960 // could either have a valid evaluatable value (for e.g. a constexpr
4961 // variable) or be ill-formed (and trigger an appropriate evaluation
4962 // diagnostic)).
4963 if (Info.CurrentCall->Callee &&
4964 Info.CurrentCall->Callee->Equals(VD->getDeclContext())) {
4965 Frame = Info.CurrentCall;
4966 }
4967 }
4968
4969 if (!VD->getType()->isReferenceType()) {
4970 if (Frame) {
4971 Result.set(VD, Frame->Index);
4972 return true;
4973 }
4974 return Success(VD);
4975 }
4976
4977 APValue *V;
4978 if (!evaluateVarDeclInit(Info, E, VD, Frame, V))
4979 return false;
4980 if (V->isUninit()) {
4981 if (!Info.checkingPotentialConstantExpression())
4982 Info.FFDiag(E, diag::note_constexpr_use_uninit_reference);
4983 return false;
4984 }
4985 return Success(*V, E);
4986}
4987
4988bool LValueExprEvaluator::VisitMaterializeTemporaryExpr(
4989 const MaterializeTemporaryExpr *E) {
4990 // Walk through the expression to find the materialized temporary itself.
4991 SmallVector<const Expr *, 2> CommaLHSs;
4992 SmallVector<SubobjectAdjustment, 2> Adjustments;
4993 const Expr *Inner = E->GetTemporaryExpr()->
4994 skipRValueSubobjectAdjustments(CommaLHSs, Adjustments);
4995
4996 // If we passed any comma operators, evaluate their LHSs.
4997 for (unsigned I = 0, N = CommaLHSs.size(); I != N; ++I)
4998 if (!EvaluateIgnoredValue(Info, CommaLHSs[I]))
4999 return false;
5000
5001 // A materialized temporary with static storage duration can appear within the
5002 // result of a constant expression evaluation, so we need to preserve its
5003 // value for use outside this evaluation.
5004 APValue *Value;
5005 if (E->getStorageDuration() == SD_Static) {
5006 Value = Info.Ctx.getMaterializedTemporaryValue(E, true);
5007 *Value = APValue();
5008 Result.set(E);
5009 } else {
5010 Value = &Info.CurrentCall->
5011 createTemporary(E, E->getStorageDuration() == SD_Automatic);
5012 Result.set(E, Info.CurrentCall->Index);
5013 }
5014
5015 QualType Type = Inner->getType();
5016
5017 // Materialize the temporary itself.
5018 if (!EvaluateInPlace(*Value, Info, Result, Inner) ||
5019 (E->getStorageDuration() == SD_Static &&
5020 !CheckConstantExpression(Info, E->getExprLoc(), Type, *Value))) {
5021 *Value = APValue();
5022 return false;
5023 }
5024
5025 // Adjust our lvalue to refer to the desired subobject.
5026 for (unsigned I = Adjustments.size(); I != 0; /**/) {
5027 --I;
5028 switch (Adjustments[I].Kind) {
5029 case SubobjectAdjustment::DerivedToBaseAdjustment:
5030 if (!HandleLValueBasePath(Info, Adjustments[I].DerivedToBase.BasePath,
5031 Type, Result))
5032 return false;
5033 Type = Adjustments[I].DerivedToBase.BasePath->getType();
5034 break;
5035
5036 case SubobjectAdjustment::FieldAdjustment:
5037 if (!HandleLValueMember(Info, E, Result, Adjustments[I].Field))
5038 return false;
5039 Type = Adjustments[I].Field->getType();
5040 break;
5041
5042 case SubobjectAdjustment::MemberPointerAdjustment:
5043 if (!HandleMemberPointerAccess(this->Info, Type, Result,
5044 Adjustments[I].Ptr.RHS))
5045 return false;
5046 Type = Adjustments[I].Ptr.MPT->getPointeeType();
5047 break;
5048 }
5049 }
5050
5051 return true;
5052}
5053
5054bool
5055LValueExprEvaluator::VisitCompoundLiteralExpr(const CompoundLiteralExpr *E) {
5056 assert((!Info.getLangOpts().CPlusPlus || E->isFileScope()) &&(((!Info.getLangOpts().CPlusPlus || E->isFileScope()) &&
"lvalue compound literal in c++?") ? static_cast<void>
(0) : __assert_fail ("(!Info.getLangOpts().CPlusPlus || E->isFileScope()) && \"lvalue compound literal in c++?\""
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 5057, __PRETTY_FUNCTION__))
5057 "lvalue compound literal in c++?")(((!Info.getLangOpts().CPlusPlus || E->isFileScope()) &&
"lvalue compound literal in c++?") ? static_cast<void>
(0) : __assert_fail ("(!Info.getLangOpts().CPlusPlus || E->isFileScope()) && \"lvalue compound literal in c++?\""
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 5057, __PRETTY_FUNCTION__))
;
5058 // Defer visiting the literal until the lvalue-to-rvalue conversion. We can
5059 // only see this when folding in C, so there's no standard to follow here.
5060 return Success(E);
5061}
5062
5063bool LValueExprEvaluator::VisitCXXTypeidExpr(const CXXTypeidExpr *E) {
5064 if (!E->isPotentiallyEvaluated())
5065 return Success(E);
5066
5067 Info.FFDiag(E, diag::note_constexpr_typeid_polymorphic)
5068 << E->getExprOperand()->getType()
5069 << E->getExprOperand()->getSourceRange();
5070 return false;
5071}
5072
5073bool LValueExprEvaluator::VisitCXXUuidofExpr(const CXXUuidofExpr *E) {
5074 return Success(E);
5075}
5076
5077bool LValueExprEvaluator::VisitMemberExpr(const MemberExpr *E) {
5078 // Handle static data members.
5079 if (const VarDecl *VD = dyn_cast<VarDecl>(E->getMemberDecl())) {
5080 VisitIgnoredBaseExpression(E->getBase());
5081 return VisitVarDecl(E, VD);
5082 }
5083
5084 // Handle static member functions.
5085 if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(E->getMemberDecl())) {
5086 if (MD->isStatic()) {
5087 VisitIgnoredBaseExpression(E->getBase());
5088 return Success(MD);
5089 }
5090 }
5091
5092 // Handle non-static data members.
5093 return LValueExprEvaluatorBaseTy::VisitMemberExpr(E);
5094}
5095
5096bool LValueExprEvaluator::VisitArraySubscriptExpr(const ArraySubscriptExpr *E) {
5097 // FIXME: Deal with vectors as array subscript bases.
5098 if (E->getBase()->getType()->isVectorType())
5099 return Error(E);
5100
5101 if (!EvaluatePointer(E->getBase(), Result, Info))
5102 return false;
5103
5104 APSInt Index;
5105 if (!EvaluateInteger(E->getIdx(), Index, Info))
5106 return false;
5107
5108 return HandleLValueArrayAdjustment(Info, E, Result, E->getType(),
5109 getExtValue(Index));
5110}
5111
5112bool LValueExprEvaluator::VisitUnaryDeref(const UnaryOperator *E) {
5113 return EvaluatePointer(E->getSubExpr(), Result, Info);
5114}
5115
5116bool LValueExprEvaluator::VisitUnaryReal(const UnaryOperator *E) {
5117 if (!Visit(E->getSubExpr()))
5118 return false;
5119 // __real is a no-op on scalar lvalues.
5120 if (E->getSubExpr()->getType()->isAnyComplexType())
5121 HandleLValueComplexElement(Info, E, Result, E->getType(), false);
5122 return true;
5123}
5124
5125bool LValueExprEvaluator::VisitUnaryImag(const UnaryOperator *E) {
5126 assert(E->getSubExpr()->getType()->isAnyComplexType() &&((E->getSubExpr()->getType()->isAnyComplexType() &&
"lvalue __imag__ on scalar?") ? static_cast<void> (0) :
__assert_fail ("E->getSubExpr()->getType()->isAnyComplexType() && \"lvalue __imag__ on scalar?\""
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 5127, __PRETTY_FUNCTION__))
5127 "lvalue __imag__ on scalar?")((E->getSubExpr()->getType()->isAnyComplexType() &&
"lvalue __imag__ on scalar?") ? static_cast<void> (0) :
__assert_fail ("E->getSubExpr()->getType()->isAnyComplexType() && \"lvalue __imag__ on scalar?\""
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 5127, __PRETTY_FUNCTION__))
;
5128 if (!Visit(E->getSubExpr()))
5129 return false;
5130 HandleLValueComplexElement(Info, E, Result, E->getType(), true);
5131 return true;
5132}
5133
5134bool LValueExprEvaluator::VisitUnaryPreIncDec(const UnaryOperator *UO) {
5135 if (!Info.getLangOpts().CPlusPlus14 && !Info.keepEvaluatingAfterFailure())
5136 return Error(UO);
5137
5138 if (!this->Visit(UO->getSubExpr()))
5139 return false;
5140
5141 return handleIncDec(
5142 this->Info, UO, Result, UO->getSubExpr()->getType(),
5143 UO->isIncrementOp(), nullptr);
5144}
5145
5146bool LValueExprEvaluator::VisitCompoundAssignOperator(
5147 const CompoundAssignOperator *CAO) {
5148 if (!Info.getLangOpts().CPlusPlus14 && !Info.keepEvaluatingAfterFailure())
5149 return Error(CAO);
5150
5151 APValue RHS;
5152
5153 // The overall lvalue result is the result of evaluating the LHS.
5154 if (!this->Visit(CAO->getLHS())) {
5155 if (Info.noteFailure())
5156 Evaluate(RHS, this->Info, CAO->getRHS());
5157 return false;
5158 }
5159
5160 if (!Evaluate(RHS, this->Info, CAO->getRHS()))
5161 return false;
5162
5163 return handleCompoundAssignment(
5164 this->Info, CAO,
5165 Result, CAO->getLHS()->getType(), CAO->getComputationLHSType(),
5166 CAO->getOpForCompoundAssignment(CAO->getOpcode()), RHS);
5167}
5168
5169bool LValueExprEvaluator::VisitBinAssign(const BinaryOperator *E) {
5170 if (!Info.getLangOpts().CPlusPlus14 && !Info.keepEvaluatingAfterFailure())
5171 return Error(E);
5172
5173 APValue NewVal;
5174
5175 if (!this->Visit(E->getLHS())) {
5176 if (Info.noteFailure())
5177 Evaluate(NewVal, this->Info, E->getRHS());
5178 return false;
5179 }
5180
5181 if (!Evaluate(NewVal, this->Info, E->getRHS()))
5182 return false;
5183
5184 return handleAssignment(this->Info, E, Result, E->getLHS()->getType(),
5185 NewVal);
5186}
5187
5188//===----------------------------------------------------------------------===//
5189// Pointer Evaluation
5190//===----------------------------------------------------------------------===//
5191
5192/// \brief Attempts to compute the number of bytes available at the pointer
5193/// returned by a function with the alloc_size attribute. Returns true if we
5194/// were successful. Places an unsigned number into `Result`.
5195///
5196/// This expects the given CallExpr to be a call to a function with an
5197/// alloc_size attribute.
5198static bool getBytesReturnedByAllocSizeCall(const ASTContext &Ctx,
5199 const CallExpr *Call,
5200 llvm::APInt &Result) {
5201 const AllocSizeAttr *AllocSize = getAllocSizeAttr(Call);
5202
5203 // alloc_size args are 1-indexed, 0 means not present.
5204 assert(AllocSize && AllocSize->getElemSizeParam() != 0)((AllocSize && AllocSize->getElemSizeParam() != 0)
? static_cast<void> (0) : __assert_fail ("AllocSize && AllocSize->getElemSizeParam() != 0"
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 5204, __PRETTY_FUNCTION__))
;
5205 unsigned SizeArgNo = AllocSize->getElemSizeParam() - 1;
5206 unsigned BitsInSizeT = Ctx.getTypeSize(Ctx.getSizeType());
5207 if (Call->getNumArgs() <= SizeArgNo)
5208 return false;
5209
5210 auto EvaluateAsSizeT = [&](const Expr *E, APSInt &Into) {
5211 if (!E->EvaluateAsInt(Into, Ctx, Expr::SE_AllowSideEffects))
5212 return false;
5213 if (Into.isNegative() || !Into.isIntN(BitsInSizeT))
5214 return false;
5215 Into = Into.zextOrSelf(BitsInSizeT);
5216 return true;
5217 };
5218
5219 APSInt SizeOfElem;
5220 if (!EvaluateAsSizeT(Call->getArg(SizeArgNo), SizeOfElem))
5221 return false;
5222
5223 if (!AllocSize->getNumElemsParam()) {
5224 Result = std::move(SizeOfElem);
5225 return true;
5226 }
5227
5228 APSInt NumberOfElems;
5229 // Argument numbers start at 1
5230 unsigned NumArgNo = AllocSize->getNumElemsParam() - 1;
5231 if (!EvaluateAsSizeT(Call->getArg(NumArgNo), NumberOfElems))
5232 return false;
5233
5234 bool Overflow;
5235 llvm::APInt BytesAvailable = SizeOfElem.umul_ov(NumberOfElems, Overflow);
5236 if (Overflow)
5237 return false;
5238
5239 Result = std::move(BytesAvailable);
5240 return true;
5241}
5242
5243/// \brief Convenience function. LVal's base must be a call to an alloc_size
5244/// function.
5245static bool getBytesReturnedByAllocSizeCall(const ASTContext &Ctx,
5246 const LValue &LVal,
5247 llvm::APInt &Result) {
5248 assert(isBaseAnAllocSizeCall(LVal.getLValueBase()) &&((isBaseAnAllocSizeCall(LVal.getLValueBase()) && "Can't get the size of a non alloc_size function"
) ? static_cast<void> (0) : __assert_fail ("isBaseAnAllocSizeCall(LVal.getLValueBase()) && \"Can't get the size of a non alloc_size function\""
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 5249, __PRETTY_FUNCTION__))
5249 "Can't get the size of a non alloc_size function")((isBaseAnAllocSizeCall(LVal.getLValueBase()) && "Can't get the size of a non alloc_size function"
) ? static_cast<void> (0) : __assert_fail ("isBaseAnAllocSizeCall(LVal.getLValueBase()) && \"Can't get the size of a non alloc_size function\""
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 5249, __PRETTY_FUNCTION__))
;
5250 const auto *Base = LVal.getLValueBase().get<const Expr *>();
5251 const CallExpr *CE = tryUnwrapAllocSizeCall(Base);
5252 return getBytesReturnedByAllocSizeCall(Ctx, CE, Result);
5253}
5254
5255/// \brief Attempts to evaluate the given LValueBase as the result of a call to
5256/// a function with the alloc_size attribute. If it was possible to do so, this
5257/// function will return true, make Result's Base point to said function call,
5258/// and mark Result's Base as invalid.
5259static bool evaluateLValueAsAllocSize(EvalInfo &Info, APValue::LValueBase Base,
5260 LValue &Result) {
5261 if (!Info.allowInvalidBaseExpr() || Base.isNull())
5262 return false;
5263
5264 // Because we do no form of static analysis, we only support const variables.
5265 //
5266 // Additionally, we can't support parameters, nor can we support static
5267 // variables (in the latter case, use-before-assign isn't UB; in the former,
5268 // we have no clue what they'll be assigned to).
5269 const auto *VD =
5270 dyn_cast_or_null<VarDecl>(Base.dyn_cast<const ValueDecl *>());
5271 if (!VD || !VD->isLocalVarDecl() || !VD->getType().isConstQualified())
5272 return false;
5273
5274 const Expr *Init = VD->getAnyInitializer();
5275 if (!Init)
5276 return false;
5277
5278 const Expr *E = Init->IgnoreParens();
5279 if (!tryUnwrapAllocSizeCall(E))
5280 return false;
5281
5282 // Store E instead of E unwrapped so that the type of the LValue's base is
5283 // what the user wanted.
5284 Result.setInvalid(E);
5285
5286 QualType Pointee = E->getType()->castAs<PointerType>()->getPointeeType();
5287 Result.addUnsizedArray(Info, Pointee);
5288 return true;
5289}
5290
5291namespace {
5292class PointerExprEvaluator
5293 : public ExprEvaluatorBase<PointerExprEvaluator> {
5294 LValue &Result;
5295
5296 bool Success(const Expr *E) {
5297 Result.set(E);
5298 return true;
5299 }
5300
5301 bool visitNonBuiltinCallExpr(const CallExpr *E);
5302public:
5303
5304 PointerExprEvaluator(EvalInfo &info, LValue &Result)
5305 : ExprEvaluatorBaseTy(info), Result(Result) {}
5306
5307 bool Success(const APValue &V, const Expr *E) {
5308 Result.setFrom(Info.Ctx, V);
5309 return true;
5310 }
5311 bool ZeroInitialization(const Expr *E) {
5312 auto Offset = Info.Ctx.getTargetNullPointerValue(E->getType());
5313 Result.set((Expr*)nullptr, 0, false, true, Offset);
5314 return true;
5315 }
5316
5317 bool VisitBinaryOperator(const BinaryOperator *E);
5318 bool VisitCastExpr(const CastExpr* E);
5319 bool VisitUnaryAddrOf(const UnaryOperator *E);
5320 bool VisitObjCStringLiteral(const ObjCStringLiteral *E)
5321 { return Success(E); }
5322 bool VisitObjCBoxedExpr(const ObjCBoxedExpr *E)
5323 { return Success(E); }
5324 bool VisitAddrLabelExpr(const AddrLabelExpr *E)
5325 { return Success(E); }
5326 bool VisitCallExpr(const CallExpr *E);
5327 bool VisitBuiltinCallExpr(const CallExpr *E, unsigned BuiltinOp);
5328 bool VisitBlockExpr(const BlockExpr *E) {
5329 if (!E->getBlockDecl()->hasCaptures())
5330 return Success(E);
5331 return Error(E);
5332 }
5333 bool VisitCXXThisExpr(const CXXThisExpr *E) {
5334 // Can't look at 'this' when checking a potential constant expression.
5335 if (Info.checkingPotentialConstantExpression())
5336 return false;
5337 if (!Info.CurrentCall->This) {
5338 if (Info.getLangOpts().CPlusPlus11)
5339 Info.FFDiag(E, diag::note_constexpr_this) << E->isImplicit();
5340 else
5341 Info.FFDiag(E);
5342 return false;
5343 }
5344 Result = *Info.CurrentCall->This;
5345 return true;
5346 }
5347
5348 // FIXME: Missing: @protocol, @selector
5349};
5350} // end anonymous namespace
5351
5352static bool EvaluatePointer(const Expr* E, LValue& Result, EvalInfo &Info) {
5353 assert(E->isRValue() && E->getType()->hasPointerRepresentation())((E->isRValue() && E->getType()->hasPointerRepresentation
()) ? static_cast<void> (0) : __assert_fail ("E->isRValue() && E->getType()->hasPointerRepresentation()"
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 5353, __PRETTY_FUNCTION__))
;
5354 return PointerExprEvaluator(Info, Result).Visit(E);
5355}
5356
5357bool PointerExprEvaluator::VisitBinaryOperator(const BinaryOperator *E) {
5358 if (E->getOpcode() != BO_Add &&
5359 E->getOpcode() != BO_Sub)
5360 return ExprEvaluatorBaseTy::VisitBinaryOperator(E);
5361
5362 const Expr *PExp = E->getLHS();
5363 const Expr *IExp = E->getRHS();
5364 if (IExp->getType()->isPointerType())
5365 std::swap(PExp, IExp);
5366
5367 bool EvalPtrOK = EvaluatePointer(PExp, Result, Info);
5368 if (!EvalPtrOK && !Info.noteFailure())
5369 return false;
5370
5371 llvm::APSInt Offset;
5372 if (!EvaluateInteger(IExp, Offset, Info) || !EvalPtrOK)
5373 return false;
5374
5375 int64_t AdditionalOffset = getExtValue(Offset);
5376 if (E->getOpcode() == BO_Sub)
5377 AdditionalOffset = -AdditionalOffset;
5378
5379 QualType Pointee = PExp->getType()->castAs<PointerType>()->getPointeeType();
5380 return HandleLValueArrayAdjustment(Info, E, Result, Pointee,
5381 AdditionalOffset);
5382}
5383
5384bool PointerExprEvaluator::VisitUnaryAddrOf(const UnaryOperator *E) {
5385 return EvaluateLValue(E->getSubExpr(), Result, Info);
5386}
5387
5388bool PointerExprEvaluator::VisitCastExpr(const CastExpr* E) {
5389 const Expr* SubExpr = E->getSubExpr();
5390
5391 switch (E->getCastKind()) {
5392 default:
5393 break;
5394
5395 case CK_BitCast:
5396 case CK_CPointerToObjCPointerCast:
5397 case CK_BlockPointerToObjCPointerCast:
5398 case CK_AnyPointerToBlockPointerCast:
5399 case CK_AddressSpaceConversion:
5400 if (!Visit(SubExpr))
5401 return false;
5402 // Bitcasts to cv void* are static_casts, not reinterpret_casts, so are
5403 // permitted in constant expressions in C++11. Bitcasts from cv void* are
5404 // also static_casts, but we disallow them as a resolution to DR1312.
5405 if (!E->getType()->isVoidPointerType()) {
5406 Result.Designator.setInvalid();
5407 if (SubExpr->getType()->isVoidPointerType())
5408 CCEDiag(E, diag::note_constexpr_invalid_cast)
5409 << 3 << SubExpr->getType();
5410 else
5411 CCEDiag(E, diag::note_constexpr_invalid_cast) << 2;
5412 }
5413 if (E->getCastKind() == CK_AddressSpaceConversion && Result.IsNullPtr)
5414 ZeroInitialization(E);
5415 return true;
5416
5417 case CK_DerivedToBase:
5418 case CK_UncheckedDerivedToBase:
5419 if (!EvaluatePointer(E->getSubExpr(), Result, Info))
5420 return false;
5421 if (!Result.Base && Result.Offset.isZero())
5422 return true;
5423
5424 // Now figure out the necessary offset to add to the base LV to get from
5425 // the derived class to the base class.
5426 return HandleLValueBasePath(Info, E, E->getSubExpr()->getType()->
5427 castAs<PointerType>()->getPointeeType(),
5428 Result);
5429
5430 case CK_BaseToDerived:
5431 if (!Visit(E->getSubExpr()))
5432 return false;
5433 if (!Result.Base && Result.Offset.isZero())
5434 return true;
5435 return HandleBaseToDerivedCast(Info, E, Result);
5436
5437 case CK_NullToPointer:
5438 VisitIgnoredValue(E->getSubExpr());
5439 return ZeroInitialization(E);
5440
5441 case CK_IntegralToPointer: {
5442 CCEDiag(E, diag::note_constexpr_invalid_cast) << 2;
5443
5444 APValue Value;
5445 if (!EvaluateIntegerOrLValue(SubExpr, Value, Info))
5446 break;
5447
5448 if (Value.isInt()) {
5449 unsigned Size = Info.Ctx.getTypeSize(E->getType());
5450 uint64_t N = Value.getInt().extOrTrunc(Size).getZExtValue();
5451 Result.Base = (Expr*)nullptr;
5452 Result.InvalidBase = false;
5453 Result.Offset = CharUnits::fromQuantity(N);
5454 Result.CallIndex = 0;
5455 Result.Designator.setInvalid();
5456 Result.IsNullPtr = false;
5457 return true;
5458 } else {
5459 // Cast is of an lvalue, no need to change value.
5460 Result.setFrom(Info.Ctx, Value);
5461 return true;
5462 }
5463 }
5464 case CK_ArrayToPointerDecay:
5465 if (SubExpr->isGLValue()) {
5466 if (!EvaluateLValue(SubExpr, Result, Info))
5467 return false;
5468 } else {
5469 Result.set(SubExpr, Info.CurrentCall->Index);
5470 if (!EvaluateInPlace(Info.CurrentCall->createTemporary(SubExpr, false),
5471 Info, Result, SubExpr))
5472 return false;
5473 }
5474 // The result is a pointer to the first element of the array.
5475 if (const ConstantArrayType *CAT
5476 = Info.Ctx.getAsConstantArrayType(SubExpr->getType()))
5477 Result.addArray(Info, E, CAT);
5478 else
5479 Result.Designator.setInvalid();
5480 return true;
5481
5482 case CK_FunctionToPointerDecay:
5483 return EvaluateLValue(SubExpr, Result, Info);
5484
5485 case CK_LValueToRValue: {
5486 LValue LVal;
5487 if (!EvaluateLValue(E->getSubExpr(), LVal, Info))
5488 return false;
5489
5490 APValue RVal;
5491 // Note, we use the subexpression's type in order to retain cv-qualifiers.
5492 if (!handleLValueToRValueConversion(Info, E, E->getSubExpr()->getType(),
5493 LVal, RVal))
5494 return evaluateLValueAsAllocSize(Info, LVal.Base, Result);
5495 return Success(RVal, E);
5496 }
5497 }
5498
5499 return ExprEvaluatorBaseTy::VisitCastExpr(E);
5500}
5501
5502static CharUnits GetAlignOfType(EvalInfo &Info, QualType T) {
5503 // C++ [expr.alignof]p3:
5504 // When alignof is applied to a reference type, the result is the
5505 // alignment of the referenced type.
5506 if (const ReferenceType *Ref = T->getAs<ReferenceType>())
5507 T = Ref->getPointeeType();
5508
5509 // __alignof is defined to return the preferred alignment.
5510 return Info.Ctx.toCharUnitsFromBits(
5511 Info.Ctx.getPreferredTypeAlign(T.getTypePtr()));
5512}
5513
5514static CharUnits GetAlignOfExpr(EvalInfo &Info, const Expr *E) {
5515 E = E->IgnoreParens();
5516
5517 // The kinds of expressions that we have special-case logic here for
5518 // should be kept up to date with the special checks for those
5519 // expressions in Sema.
5520
5521 // alignof decl is always accepted, even if it doesn't make sense: we default
5522 // to 1 in those cases.
5523 if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E))
5524 return Info.Ctx.getDeclAlign(DRE->getDecl(),
5525 /*RefAsPointee*/true);
5526
5527 if (const MemberExpr *ME = dyn_cast<MemberExpr>(E))
5528 return Info.Ctx.getDeclAlign(ME->getMemberDecl(),
5529 /*RefAsPointee*/true);
5530
5531 return GetAlignOfType(Info, E->getType());
5532}
5533
5534// To be clear: this happily visits unsupported builtins. Better name welcomed.
5535bool PointerExprEvaluator::visitNonBuiltinCallExpr(const CallExpr *E) {
5536 if (ExprEvaluatorBaseTy::VisitCallExpr(E))
5537 return true;
5538
5539 if (!(Info.allowInvalidBaseExpr() && getAllocSizeAttr(E)))
5540 return false;
5541
5542 Result.setInvalid(E);
5543 QualType PointeeTy = E->getType()->castAs<PointerType>()->getPointeeType();
5544 Result.addUnsizedArray(Info, PointeeTy);
5545 return true;
5546}
5547
5548bool PointerExprEvaluator::VisitCallExpr(const CallExpr *E) {
5549 if (IsStringLiteralCall(E))
5550 return Success(E);
5551
5552 if (unsigned BuiltinOp = E->getBuiltinCallee())
5553 return VisitBuiltinCallExpr(E, BuiltinOp);
5554
5555 return visitNonBuiltinCallExpr(E);
5556}
5557
5558bool PointerExprEvaluator::VisitBuiltinCallExpr(const CallExpr *E,
5559 unsigned BuiltinOp) {
5560 switch (BuiltinOp) {
5561 case Builtin::BI__builtin_addressof:
5562 return EvaluateLValue(E->getArg(0), Result, Info);
5563 case Builtin::BI__builtin_assume_aligned: {
5564 // We need to be very careful here because: if the pointer does not have the
5565 // asserted alignment, then the behavior is undefined, and undefined
5566 // behavior is non-constant.
5567 if (!EvaluatePointer(E->getArg(0), Result, Info))
5568 return false;
5569
5570 LValue OffsetResult(Result);
5571 APSInt Alignment;
5572 if (!EvaluateInteger(E->getArg(1), Alignment, Info))
5573 return false;
5574 CharUnits Align = CharUnits::fromQuantity(getExtValue(Alignment));
5575
5576 if (E->getNumArgs() > 2) {
5577 APSInt Offset;
5578 if (!EvaluateInteger(E->getArg(2), Offset, Info))
5579 return false;
5580
5581 int64_t AdditionalOffset = -getExtValue(Offset);
5582 OffsetResult.Offset += CharUnits::fromQuantity(AdditionalOffset);
5583 }
5584
5585 // If there is a base object, then it must have the correct alignment.
5586 if (OffsetResult.Base) {
5587 CharUnits BaseAlignment;
5588 if (const ValueDecl *VD =
5589 OffsetResult.Base.dyn_cast<const ValueDecl*>()) {
5590 BaseAlignment = Info.Ctx.getDeclAlign(VD);
5591 } else {
5592 BaseAlignment =
5593 GetAlignOfExpr(Info, OffsetResult.Base.get<const Expr*>());
5594 }
5595
5596 if (BaseAlignment < Align) {
5597 Result.Designator.setInvalid();
5598 // FIXME: Quantities here cast to integers because the plural modifier
5599 // does not work on APSInts yet.
5600 CCEDiag(E->getArg(0),
5601 diag::note_constexpr_baa_insufficient_alignment) << 0
5602 << (int) BaseAlignment.getQuantity()
5603 << (unsigned) getExtValue(Alignment);
5604 return false;
5605 }
5606 }
5607
5608 // The offset must also have the correct alignment.
5609 if (OffsetResult.Offset.alignTo(Align) != OffsetResult.Offset) {
5610 Result.Designator.setInvalid();
5611 APSInt Offset(64, false);
5612 Offset = OffsetResult.Offset.getQuantity();
5613
5614 if (OffsetResult.Base)
5615 CCEDiag(E->getArg(0),
5616 diag::note_constexpr_baa_insufficient_alignment) << 1
5617 << (int) getExtValue(Offset) << (unsigned) getExtValue(Alignment);
5618 else
5619 CCEDiag(E->getArg(0),
5620 diag::note_constexpr_baa_value_insufficient_alignment)
5621 << Offset << (unsigned) getExtValue(Alignment);
5622
5623 return false;
5624 }
5625
5626 return true;
5627 }
5628
5629 case Builtin::BIstrchr:
5630 case Builtin::BIwcschr:
5631 case Builtin::BImemchr:
5632 case Builtin::BIwmemchr:
5633 if (Info.getLangOpts().CPlusPlus11)
5634 Info.CCEDiag(E, diag::note_constexpr_invalid_function)
5635 << /*isConstexpr*/0 << /*isConstructor*/0
5636 << (std::string("'") + Info.Ctx.BuiltinInfo.getName(BuiltinOp) + "'");
5637 else
5638 Info.CCEDiag(E, diag::note_invalid_subexpr_in_const_expr);
5639 // Fall through.
5640 case Builtin::BI__builtin_strchr:
5641 case Builtin::BI__builtin_wcschr:
5642 case Builtin::BI__builtin_memchr:
5643 case Builtin::BI__builtin_wmemchr: {
5644 if (!Visit(E->getArg(0)))
5645 return false;
5646 APSInt Desired;
5647 if (!EvaluateInteger(E->getArg(1), Desired, Info))
5648 return false;
5649 uint64_t MaxLength = uint64_t(-1);
5650 if (BuiltinOp != Builtin::BIstrchr &&
5651 BuiltinOp != Builtin::BIwcschr &&
5652 BuiltinOp != Builtin::BI__builtin_strchr &&
5653 BuiltinOp != Builtin::BI__builtin_wcschr) {
5654 APSInt N;
5655 if (!EvaluateInteger(E->getArg(2), N, Info))
5656 return false;
5657 MaxLength = N.getExtValue();
5658 }
5659
5660 QualType CharTy = E->getArg(0)->getType()->getPointeeType();
5661
5662 // Figure out what value we're actually looking for (after converting to
5663 // the corresponding unsigned type if necessary).
5664 uint64_t DesiredVal;
5665 bool StopAtNull = false;
5666 switch (BuiltinOp) {
5667 case Builtin::BIstrchr:
5668 case Builtin::BI__builtin_strchr:
5669 // strchr compares directly to the passed integer, and therefore
5670 // always fails if given an int that is not a char.
5671 if (!APSInt::isSameValue(HandleIntToIntCast(Info, E, CharTy,
5672 E->getArg(1)->getType(),
5673 Desired),
5674 Desired))
5675 return ZeroInitialization(E);
5676 StopAtNull = true;
5677 // Fall through.
5678 case Builtin::BImemchr:
5679 case Builtin::BI__builtin_memchr:
5680 // memchr compares by converting both sides to unsigned char. That's also
5681 // correct for strchr if we get this far (to cope with plain char being
5682 // unsigned in the strchr case).
5683 DesiredVal = Desired.trunc(Info.Ctx.getCharWidth()).getZExtValue();
5684 break;
5685
5686 case Builtin::BIwcschr:
5687 case Builtin::BI__builtin_wcschr:
5688 StopAtNull = true;
5689 // Fall through.
5690 case Builtin::BIwmemchr:
5691 case Builtin::BI__builtin_wmemchr:
5692 // wcschr and wmemchr are given a wchar_t to look for. Just use it.
5693 DesiredVal = Desired.getZExtValue();
5694 break;
5695 }
5696
5697 for (; MaxLength; --MaxLength) {
5698 APValue Char;
5699 if (!handleLValueToRValueConversion(Info, E, CharTy, Result, Char) ||
5700 !Char.isInt())
5701 return false;
5702 if (Char.getInt().getZExtValue() == DesiredVal)
5703 return true;
5704 if (StopAtNull && !Char.getInt())
5705 break;
5706 if (!HandleLValueArrayAdjustment(Info, E, Result, CharTy, 1))
5707 return false;
5708 }
5709 // Not found: return nullptr.
5710 return ZeroInitialization(E);
5711 }
5712
5713 default:
5714 return visitNonBuiltinCallExpr(E);
5715 }
5716}
5717
5718//===----------------------------------------------------------------------===//
5719// Member Pointer Evaluation
5720//===----------------------------------------------------------------------===//
5721
5722namespace {
5723class MemberPointerExprEvaluator
5724 : public ExprEvaluatorBase<MemberPointerExprEvaluator> {
5725 MemberPtr &Result;
5726
5727 bool Success(const ValueDecl *D) {
5728 Result = MemberPtr(D);
5729 return true;
5730 }
5731public:
5732
5733 MemberPointerExprEvaluator(EvalInfo &Info, MemberPtr &Result)
5734 : ExprEvaluatorBaseTy(Info), Result(Result) {}
5735
5736 bool Success(const APValue &V, const Expr *E) {
5737 Result.setFrom(V);
5738 return true;
5739 }
5740 bool ZeroInitialization(const Expr *E) {
5741 return Success((const ValueDecl*)nullptr);
5742 }
5743
5744 bool VisitCastExpr(const CastExpr *E);
5745 bool VisitUnaryAddrOf(const UnaryOperator *E);
5746};
5747} // end anonymous namespace
5748
5749static bool EvaluateMemberPointer(const Expr *E, MemberPtr &Result,
5750 EvalInfo &Info) {
5751 assert(E->isRValue() && E->getType()->isMemberPointerType())((E->isRValue() && E->getType()->isMemberPointerType
()) ? static_cast<void> (0) : __assert_fail ("E->isRValue() && E->getType()->isMemberPointerType()"
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 5751, __PRETTY_FUNCTION__))
;
5752 return MemberPointerExprEvaluator(Info, Result).Visit(E);
5753}
5754
5755bool MemberPointerExprEvaluator::VisitCastExpr(const CastExpr *E) {
5756 switch (E->getCastKind()) {
5757 default:
5758 return ExprEvaluatorBaseTy::VisitCastExpr(E);
5759
5760 case CK_NullToMemberPointer:
5761 VisitIgnoredValue(E->getSubExpr());
5762 return ZeroInitialization(E);
5763
5764 case CK_BaseToDerivedMemberPointer: {
5765 if (!Visit(E->getSubExpr()))
5766 return false;
5767 if (E->path_empty())
5768 return true;
5769 // Base-to-derived member pointer casts store the path in derived-to-base
5770 // order, so iterate backwards. The CXXBaseSpecifier also provides us with
5771 // the wrong end of the derived->base arc, so stagger the path by one class.
5772 typedef std::reverse_iterator<CastExpr::path_const_iterator> ReverseIter;
5773 for (ReverseIter PathI(E->path_end() - 1), PathE(E->path_begin());
5774 PathI != PathE; ++PathI) {
5775 assert(!(*PathI)->isVirtual() && "memptr cast through vbase")((!(*PathI)->isVirtual() && "memptr cast through vbase"
) ? static_cast<void> (0) : __assert_fail ("!(*PathI)->isVirtual() && \"memptr cast through vbase\""
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 5775, __PRETTY_FUNCTION__))
;
5776 const CXXRecordDecl *Derived = (*PathI)->getType()->getAsCXXRecordDecl();
5777 if (!Result.castToDerived(Derived))
5778 return Error(E);
5779 }
5780 const Type *FinalTy = E->getType()->castAs<MemberPointerType>()->getClass();
5781 if (!Result.castToDerived(FinalTy->getAsCXXRecordDecl()))
5782 return Error(E);
5783 return true;
5784 }
5785
5786 case CK_DerivedToBaseMemberPointer:
5787 if (!Visit(E->getSubExpr()))
5788 return false;
5789 for (CastExpr::path_const_iterator PathI = E->path_begin(),
5790 PathE = E->path_end(); PathI != PathE; ++PathI) {
5791 assert(!(*PathI)->isVirtual() && "memptr cast through vbase")((!(*PathI)->isVirtual() && "memptr cast through vbase"
) ? static_cast<void> (0) : __assert_fail ("!(*PathI)->isVirtual() && \"memptr cast through vbase\""
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 5791, __PRETTY_FUNCTION__))
;
5792 const CXXRecordDecl *Base = (*PathI)->getType()->getAsCXXRecordDecl();
5793 if (!Result.castToBase(Base))
5794 return Error(E);
5795 }
5796 return true;
5797 }
5798}
5799
5800bool MemberPointerExprEvaluator::VisitUnaryAddrOf(const UnaryOperator *E) {
5801 // C++11 [expr.unary.op]p3 has very strict rules on how the address of a
5802 // member can be formed.
5803 return Success(cast<DeclRefExpr>(E->getSubExpr())->getDecl());
5804}
5805
5806//===----------------------------------------------------------------------===//
5807// Record Evaluation
5808//===----------------------------------------------------------------------===//
5809
5810namespace {
5811 class RecordExprEvaluator
5812 : public ExprEvaluatorBase<RecordExprEvaluator> {
5813 const LValue &This;
5814 APValue &Result;
5815 public:
5816
5817 RecordExprEvaluator(EvalInfo &info, const LValue &This, APValue &Result)
5818 : ExprEvaluatorBaseTy(info), This(This), Result(Result) {}
5819
5820 bool Success(const APValue &V, const Expr *E) {
5821 Result = V;
5822 return true;
5823 }
5824 bool ZeroInitialization(const Expr *E) {
5825 return ZeroInitialization(E, E->getType());
5826 }
5827 bool ZeroInitialization(const Expr *E, QualType T);
5828
5829 bool VisitCallExpr(const CallExpr *E) {
5830 return handleCallExpr(E, Result, &This);
5831 }
5832 bool VisitCastExpr(const CastExpr *E);
5833 bool VisitInitListExpr(const InitListExpr *E);
5834 bool VisitCXXConstructExpr(const CXXConstructExpr *E) {
5835 return VisitCXXConstructExpr(E, E->getType());
5836 }
5837 bool VisitCXXInheritedCtorInitExpr(const CXXInheritedCtorInitExpr *E);
5838 bool VisitCXXConstructExpr(const CXXConstructExpr *E, QualType T);
5839 bool VisitCXXStdInitializerListExpr(const CXXStdInitializerListExpr *E);
5840 };
5841}
5842
5843/// Perform zero-initialization on an object of non-union class type.
5844/// C++11 [dcl.init]p5:
5845/// To zero-initialize an object or reference of type T means:
5846/// [...]
5847/// -- if T is a (possibly cv-qualified) non-union class type,
5848/// each non-static data member and each base-class subobject is
5849/// zero-initialized
5850static bool HandleClassZeroInitialization(EvalInfo &Info, const Expr *E,
5851 const RecordDecl *RD,
5852 const LValue &This, APValue &Result) {
5853 assert(!RD->isUnion() && "Expected non-union class type")((!RD->isUnion() && "Expected non-union class type"
) ? static_cast<void> (0) : __assert_fail ("!RD->isUnion() && \"Expected non-union class type\""
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 5853, __PRETTY_FUNCTION__))
;
5854 const CXXRecordDecl *CD = dyn_cast<CXXRecordDecl>(RD);
5855 Result = APValue(APValue::UninitStruct(), CD ? CD->getNumBases() : 0,
5856 std::distance(RD->field_begin(), RD->field_end()));
5857
5858 if (RD->isInvalidDecl()) return false;
5859 const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(RD);
5860
5861 if (CD) {
5862 unsigned Index = 0;
5863 for (CXXRecordDecl::base_class_const_iterator I = CD->bases_begin(),
5864 End = CD->bases_end(); I != End; ++I, ++Index) {
5865 const CXXRecordDecl *Base = I->getType()->getAsCXXRecordDecl();
5866 LValue Subobject = This;
5867 if (!HandleLValueDirectBase(Info, E, Subobject, CD, Base, &Layout))
5868 return false;
5869 if (!HandleClassZeroInitialization(Info, E, Base, Subobject,
5870 Result.getStructBase(Index)))
5871 return false;
5872 }
5873 }
5874
5875 for (const auto *I : RD->fields()) {
5876 // -- if T is a reference type, no initialization is performed.
5877 if (I->getType()->isReferenceType())
5878 continue;
5879
5880 LValue Subobject = This;
5881 if (!HandleLValueMember(Info, E, Subobject, I, &Layout))
5882 return false;
5883
5884 ImplicitValueInitExpr VIE(I->getType());
5885 if (!EvaluateInPlace(
5886 Result.getStructField(I->getFieldIndex()), Info, Subobject, &VIE))
5887 return false;
5888 }
5889
5890 return true;
5891}
5892
5893bool RecordExprEvaluator::ZeroInitialization(const Expr *E, QualType T) {
5894 const RecordDecl *RD = T->castAs<RecordType>()->getDecl();
5895 if (RD->isInvalidDecl()) return false;
5896 if (RD->isUnion()) {
5897 // C++11 [dcl.init]p5: If T is a (possibly cv-qualified) union type, the
5898 // object's first non-static named data member is zero-initialized
5899 RecordDecl::field_iterator I = RD->field_begin();
5900 if (I == RD->field_end()) {
5901 Result = APValue((const FieldDecl*)nullptr);
5902 return true;
5903 }
5904
5905 LValue Subobject = This;
5906 if (!HandleLValueMember(Info, E, Subobject, *I))
5907 return false;
5908 Result = APValue(*I);
5909 ImplicitValueInitExpr VIE(I->getType());
5910 return EvaluateInPlace(Result.getUnionValue(), Info, Subobject, &VIE);
5911 }
5912
5913 if (isa<CXXRecordDecl>(RD) && cast<CXXRecordDecl>(RD)->getNumVBases()) {
5914 Info.FFDiag(E, diag::note_constexpr_virtual_base) << RD;
5915 return false;
5916 }
5917
5918 return HandleClassZeroInitialization(Info, E, RD, This, Result);
5919}
5920
5921bool RecordExprEvaluator::VisitCastExpr(const CastExpr *E) {
5922 switch (E->getCastKind()) {
5923 default:
5924 return ExprEvaluatorBaseTy::VisitCastExpr(E);
5925
5926 case CK_ConstructorConversion:
5927 return Visit(E->getSubExpr());
5928
5929 case CK_DerivedToBase:
5930 case CK_UncheckedDerivedToBase: {
5931 APValue DerivedObject;
5932 if (!Evaluate(DerivedObject, Info, E->getSubExpr()))
5933 return false;
5934 if (!DerivedObject.isStruct())
5935 return Error(E->getSubExpr());
5936
5937 // Derived-to-base rvalue conversion: just slice off the derived part.
5938 APValue *Value = &DerivedObject;
5939 const CXXRecordDecl *RD = E->getSubExpr()->getType()->getAsCXXRecordDecl();
5940 for (CastExpr::path_const_iterator PathI = E->path_begin(),
5941 PathE = E->path_end(); PathI != PathE; ++PathI) {
5942 assert(!(*PathI)->isVirtual() && "record rvalue with virtual base")((!(*PathI)->isVirtual() && "record rvalue with virtual base"
) ? static_cast<void> (0) : __assert_fail ("!(*PathI)->isVirtual() && \"record rvalue with virtual base\""
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 5942, __PRETTY_FUNCTION__))
;
5943 const CXXRecordDecl *Base = (*PathI)->getType()->getAsCXXRecordDecl();
5944 Value = &Value->getStructBase(getBaseIndex(RD, Base));
5945 RD = Base;
5946 }
5947 Result = *Value;
5948 return true;
5949 }
5950 }
5951}
5952
5953bool RecordExprEvaluator::VisitInitListExpr(const InitListExpr *E) {
5954 if (E->isTransparent())
5955 return Visit(E->getInit(0));
5956
5957 const RecordDecl *RD = E->getType()->castAs<RecordType>()->getDecl();
5958 if (RD->isInvalidDecl()) return false;
5959 const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(RD);
5960
5961 if (RD->isUnion()) {
5962 const FieldDecl *Field = E->getInitializedFieldInUnion();
5963 Result = APValue(Field);
5964 if (!Field)
5965 return true;
5966
5967 // If the initializer list for a union does not contain any elements, the
5968 // first element of the union is value-initialized.
5969 // FIXME: The element should be initialized from an initializer list.
5970 // Is this difference ever observable for initializer lists which
5971 // we don't build?
5972 ImplicitValueInitExpr VIE(Field->getType());
5973 const Expr *InitExpr = E->getNumInits() ? E->getInit(0) : &VIE;
5974
5975 LValue Subobject = This;
5976 if (!HandleLValueMember(Info, InitExpr, Subobject, Field, &Layout))
5977 return false;
5978
5979 // Temporarily override This, in case there's a CXXDefaultInitExpr in here.
5980 ThisOverrideRAII ThisOverride(*Info.CurrentCall, &This,
5981 isa<CXXDefaultInitExpr>(InitExpr));
5982
5983 return EvaluateInPlace(Result.getUnionValue(), Info, Subobject, InitExpr);
5984 }
5985
5986 auto *CXXRD = dyn_cast<CXXRecordDecl>(RD);
5987 if (Result.isUninit())
5988 Result = APValue(APValue::UninitStruct(), CXXRD ? CXXRD->getNumBases() : 0,
5989 std::distance(RD->field_begin(), RD->field_end()));
5990 unsigned ElementNo = 0;
5991 bool Success = true;
5992
5993 // Initialize base classes.
5994 if (CXXRD) {
5995 for (const auto &Base : CXXRD->bases()) {
5996 assert(ElementNo < E->getNumInits() && "missing init for base class")((ElementNo < E->getNumInits() && "missing init for base class"
) ? static_cast<void> (0) : __assert_fail ("ElementNo < E->getNumInits() && \"missing init for base class\""
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 5996, __PRETTY_FUNCTION__))
;
5997 const Expr *Init = E->getInit(ElementNo);
5998
5999 LValue Subobject = This;
6000 if (!HandleLValueBase(Info, Init, Subobject, CXXRD, &Base))
6001 return false;
6002
6003 APValue &FieldVal = Result.getStructBase(ElementNo);
6004 if (!EvaluateInPlace(FieldVal, Info, Subobject, Init)) {
6005 if (!Info.noteFailure())
6006 return false;
6007 Success = false;
6008 }
6009 ++ElementNo;
6010 }
6011 }
6012
6013 // Initialize members.
6014 for (const auto *Field : RD->fields()) {
6015 // Anonymous bit-fields are not considered members of the class for
6016 // purposes of aggregate initialization.
6017 if (Field->isUnnamedBitfield())
6018 continue;
6019
6020 LValue Subobject = This;
6021
6022 bool HaveInit = ElementNo < E->getNumInits();
6023
6024 // FIXME: Diagnostics here should point to the end of the initializer
6025 // list, not the start.
6026 if (!HandleLValueMember(Info, HaveInit ? E->getInit(ElementNo) : E,
6027 Subobject, Field, &Layout))
6028 return false;
6029
6030 // Perform an implicit value-initialization for members beyond the end of
6031 // the initializer list.
6032 ImplicitValueInitExpr VIE(HaveInit ? Info.Ctx.IntTy : Field->getType());
6033 const Expr *Init = HaveInit ? E->getInit(ElementNo++) : &VIE;
6034
6035 // Temporarily override This, in case there's a CXXDefaultInitExpr in here.
6036 ThisOverrideRAII ThisOverride(*Info.CurrentCall, &This,
6037 isa<CXXDefaultInitExpr>(Init));
6038
6039 APValue &FieldVal = Result.getStructField(Field->getFieldIndex());
6040 if (!EvaluateInPlace(FieldVal, Info, Subobject, Init) ||
6041 (Field->isBitField() && !truncateBitfieldValue(Info, Init,
6042 FieldVal, Field))) {
6043 if (!Info.noteFailure())
6044 return false;
6045 Success = false;
6046 }
6047 }
6048
6049 return Success;
6050}
6051
6052bool RecordExprEvaluator::VisitCXXConstructExpr(const CXXConstructExpr *E,
6053 QualType T) {
6054 // Note that E's type is not necessarily the type of our class here; we might
6055 // be initializing an array element instead.
6056 const CXXConstructorDecl *FD = E->getConstructor();
6057 if (FD->isInvalidDecl() || FD->getParent()->isInvalidDecl()) return false;
6058
6059 bool ZeroInit = E->requiresZeroInitialization();
6060 if (CheckTrivialDefaultConstructor(Info, E->getExprLoc(), FD, ZeroInit)) {
6061 // If we've already performed zero-initialization, we're already done.
6062 if (!Result.isUninit())
6063 return true;
6064
6065 // We can get here in two different ways:
6066 // 1) We're performing value-initialization, and should zero-initialize
6067 // the object, or
6068 // 2) We're performing default-initialization of an object with a trivial
6069 // constexpr default constructor, in which case we should start the
6070 // lifetimes of all the base subobjects (there can be no data member
6071 // subobjects in this case) per [basic.life]p1.
6072 // Either way, ZeroInitialization is appropriate.
6073 return ZeroInitialization(E, T);
6074 }
6075
6076 const FunctionDecl *Definition = nullptr;
6077 auto Body = FD->getBody(Definition);
6078
6079 if (!CheckConstexprFunction(Info, E->getExprLoc(), FD, Definition, Body))
6080 return false;
6081
6082 // Avoid materializing a temporary for an elidable copy/move constructor.
6083 if (E->isElidable() && !ZeroInit)
6084 if (const MaterializeTemporaryExpr *ME
6085 = dyn_cast<MaterializeTemporaryExpr>(E->getArg(0)))
6086 return Visit(ME->GetTemporaryExpr());
6087
6088 if (ZeroInit && !ZeroInitialization(E, T))
6089 return false;
6090
6091 auto Args = llvm::makeArrayRef(E->getArgs(), E->getNumArgs());
6092 return HandleConstructorCall(E, This, Args,
6093 cast<CXXConstructorDecl>(Definition), Info,
6094 Result);
6095}
6096
6097bool RecordExprEvaluator::VisitCXXInheritedCtorInitExpr(
6098 const CXXInheritedCtorInitExpr *E) {
6099 if (!Info.CurrentCall) {
6100 assert(Info.checkingPotentialConstantExpression())((Info.checkingPotentialConstantExpression()) ? static_cast<
void> (0) : __assert_fail ("Info.checkingPotentialConstantExpression()"
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 6100, __PRETTY_FUNCTION__))
;
6101 return false;
6102 }
6103
6104 const CXXConstructorDecl *FD = E->getConstructor();
6105 if (FD->isInvalidDecl() || FD->getParent()->isInvalidDecl())
6106 return false;
6107
6108 const FunctionDecl *Definition = nullptr;
6109 auto Body = FD->getBody(Definition);
6110
6111 if (!CheckConstexprFunction(Info, E->getExprLoc(), FD, Definition, Body))
6112 return false;
6113
6114 return HandleConstructorCall(E, This, Info.CurrentCall->Arguments,
6115 cast<CXXConstructorDecl>(Definition), Info,
6116 Result);
6117}
6118
6119bool RecordExprEvaluator::VisitCXXStdInitializerListExpr(
6120 const CXXStdInitializerListExpr *E) {
6121 const ConstantArrayType *ArrayType =
6122 Info.Ctx.getAsConstantArrayType(E->getSubExpr()->getType());
6123
6124 LValue Array;
6125 if (!EvaluateLValue(E->getSubExpr(), Array, Info))
6126 return false;
6127
6128 // Get a pointer to the first element of the array.
6129 Array.addArray(Info, E, ArrayType);
6130
6131 // FIXME: Perform the checks on the field types in SemaInit.
6132 RecordDecl *Record = E->getType()->castAs<RecordType>()->getDecl();
6133 RecordDecl::field_iterator Field = Record->field_begin();
6134 if (Field == Record->field_end())
6135 return Error(E);
6136
6137 // Start pointer.
6138 if (!Field->getType()->isPointerType() ||
6139 !Info.Ctx.hasSameType(Field->getType()->getPointeeType(),
6140 ArrayType->getElementType()))
6141 return Error(E);
6142
6143 // FIXME: What if the initializer_list type has base classes, etc?
6144 Result = APValue(APValue::UninitStruct(), 0, 2);
6145 Array.moveInto(Result.getStructField(0));
6146
6147 if (++Field == Record->field_end())
6148 return Error(E);
6149
6150 if (Field->getType()->isPointerType() &&
6151 Info.Ctx.hasSameType(Field->getType()->getPointeeType(),
6152 ArrayType->getElementType())) {
6153 // End pointer.
6154 if (!HandleLValueArrayAdjustment(Info, E, Array,
6155 ArrayType->getElementType(),
6156 ArrayType->getSize().getZExtValue()))
6157 return false;
6158 Array.moveInto(Result.getStructField(1));
6159 } else if (Info.Ctx.hasSameType(Field->getType(), Info.Ctx.getSizeType()))
6160 // Length.
6161 Result.getStructField(1) = APValue(APSInt(ArrayType->getSize()));
6162 else
6163 return Error(E);
6164
6165 if (++Field != Record->field_end())
6166 return Error(E);
6167
6168 return true;
6169}
6170
6171static bool EvaluateRecord(const Expr *E, const LValue &This,
6172 APValue &Result, EvalInfo &Info) {
6173 assert(E->isRValue() && E->getType()->isRecordType() &&((E->isRValue() && E->getType()->isRecordType
() && "can't evaluate expression as a record rvalue")
? static_cast<void> (0) : __assert_fail ("E->isRValue() && E->getType()->isRecordType() && \"can't evaluate expression as a record rvalue\""
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 6174, __PRETTY_FUNCTION__))
6174 "can't evaluate expression as a record rvalue")((E->isRValue() && E->getType()->isRecordType
() && "can't evaluate expression as a record rvalue")
? static_cast<void> (0) : __assert_fail ("E->isRValue() && E->getType()->isRecordType() && \"can't evaluate expression as a record rvalue\""
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 6174, __PRETTY_FUNCTION__))
;
6175 return RecordExprEvaluator(Info, This, Result).Visit(E);
6176}
6177
6178//===----------------------------------------------------------------------===//
6179// Temporary Evaluation
6180//
6181// Temporaries are represented in the AST as rvalues, but generally behave like
6182// lvalues. The full-object of which the temporary is a subobject is implicitly
6183// materialized so that a reference can bind to it.
6184//===----------------------------------------------------------------------===//
6185namespace {
6186class TemporaryExprEvaluator
6187 : public LValueExprEvaluatorBase<TemporaryExprEvaluator> {
6188public:
6189 TemporaryExprEvaluator(EvalInfo &Info, LValue &Result) :
6190 LValueExprEvaluatorBaseTy(Info, Result) {}
6191
6192 /// Visit an expression which constructs the value of this temporary.
6193 bool VisitConstructExpr(const Expr *E) {
6194 Result.set(E, Info.CurrentCall->Index);
6195 return EvaluateInPlace(Info.CurrentCall->createTemporary(E, false),
6196 Info, Result, E);
6197 }
6198
6199 bool VisitCastExpr(const CastExpr *E) {
6200 switch (E->getCastKind()) {
6201 default:
6202 return LValueExprEvaluatorBaseTy::VisitCastExpr(E);
6203
6204 case CK_ConstructorConversion:
6205 return VisitConstructExpr(E->getSubExpr());
6206 }
6207 }
6208 bool VisitInitListExpr(const InitListExpr *E) {
6209 return VisitConstructExpr(E);
6210 }
6211 bool VisitCXXConstructExpr(const CXXConstructExpr *E) {
6212 return VisitConstructExpr(E);
6213 }
6214 bool VisitCallExpr(const CallExpr *E) {
6215 return VisitConstructExpr(E);
6216 }
6217 bool VisitCXXStdInitializerListExpr(const CXXStdInitializerListExpr *E) {
6218 return VisitConstructExpr(E);
6219 }
6220};
6221} // end anonymous namespace
6222
6223/// Evaluate an expression of record type as a temporary.
6224static bool EvaluateTemporary(const Expr *E, LValue &Result, EvalInfo &Info) {
6225 assert(E->isRValue() && E->getType()->isRecordType())((E->isRValue() && E->getType()->isRecordType
()) ? static_cast<void> (0) : __assert_fail ("E->isRValue() && E->getType()->isRecordType()"
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 6225, __PRETTY_FUNCTION__))
;
6226 return TemporaryExprEvaluator(Info, Result).Visit(E);
6227}
6228
6229//===----------------------------------------------------------------------===//
6230// Vector Evaluation
6231//===----------------------------------------------------------------------===//
6232
6233namespace {
6234 class VectorExprEvaluator
6235 : public ExprEvaluatorBase<VectorExprEvaluator> {
6236 APValue &Result;
6237 public:
6238
6239 VectorExprEvaluator(EvalInfo &info, APValue &Result)
6240 : ExprEvaluatorBaseTy(info), Result(Result) {}
6241
6242 bool Success(ArrayRef<APValue> V, const Expr *E) {
6243 assert(V.size() == E->getType()->castAs<VectorType>()->getNumElements())((V.size() == E->getType()->castAs<VectorType>()->
getNumElements()) ? static_cast<void> (0) : __assert_fail
("V.size() == E->getType()->castAs<VectorType>()->getNumElements()"
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 6243, __PRETTY_FUNCTION__))
;
6244 // FIXME: remove this APValue copy.
6245 Result = APValue(V.data(), V.size());
6246 return true;
6247 }
6248 bool Success(const APValue &V, const Expr *E) {
6249 assert(V.isVector())((V.isVector()) ? static_cast<void> (0) : __assert_fail
("V.isVector()", "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 6249, __PRETTY_FUNCTION__))
;
6250 Result = V;
6251 return true;
6252 }
6253 bool ZeroInitialization(const Expr *E);
6254
6255 bool VisitUnaryReal(const UnaryOperator *E)
6256 { return Visit(E->getSubExpr()); }
6257 bool VisitCastExpr(const CastExpr* E);
6258 bool VisitInitListExpr(const InitListExpr *E);
6259 bool VisitUnaryImag(const UnaryOperator *E);
6260 // FIXME: Missing: unary -, unary ~, binary add/sub/mul/div,
6261 // binary comparisons, binary and/or/xor,
6262 // shufflevector, ExtVectorElementExpr
6263 };
6264} // end anonymous namespace
6265
6266static bool EvaluateVector(const Expr* E, APValue& Result, EvalInfo &Info) {
6267 assert(E->isRValue() && E->getType()->isVectorType() &&"not a vector rvalue")((E->isRValue() && E->getType()->isVectorType
() &&"not a vector rvalue") ? static_cast<void>
(0) : __assert_fail ("E->isRValue() && E->getType()->isVectorType() &&\"not a vector rvalue\""
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 6267, __PRETTY_FUNCTION__))
;
6268 return VectorExprEvaluator(Info, Result).Visit(E);
6269}
6270
6271bool VectorExprEvaluator::VisitCastExpr(const CastExpr *E) {
6272 const VectorType *VTy = E->getType()->castAs<VectorType>();
6273 unsigned NElts = VTy->getNumElements();
6274
6275 const Expr *SE = E->getSubExpr();
6276 QualType SETy = SE->getType();
6277
6278 switch (E->getCastKind()) {
6279 case CK_VectorSplat: {
6280 APValue Val = APValue();
6281 if (SETy->isIntegerType()) {
6282 APSInt IntResult;
6283 if (!EvaluateInteger(SE, IntResult, Info))
6284 return false;
6285 Val = APValue(std::move(IntResult));
6286 } else if (SETy->isRealFloatingType()) {
6287 APFloat FloatResult(0.0);
6288 if (!EvaluateFloat(SE, FloatResult, Info))
6289 return false;
6290 Val = APValue(std::move(FloatResult));
6291 } else {
6292 return Error(E);
6293 }
6294
6295 // Splat and create vector APValue.
6296 SmallVector<APValue, 4> Elts(NElts, Val);
6297 return Success(Elts, E);
6298 }
6299 case CK_BitCast: {
6300 // Evaluate the operand into an APInt we can extract from.
6301 llvm::APInt SValInt;
6302 if (!EvalAndBitcastToAPInt(Info, SE, SValInt))
6303 return false;
6304 // Extract the elements
6305 QualType EltTy = VTy->getElementType();
6306 unsigned EltSize = Info.Ctx.getTypeSize(EltTy);
6307 bool BigEndian = Info.Ctx.getTargetInfo().isBigEndian();
6308 SmallVector<APValue, 4> Elts;
6309 if (EltTy->isRealFloatingType()) {
6310 const llvm::fltSemantics &Sem = Info.Ctx.getFloatTypeSemantics(EltTy);
6311 unsigned FloatEltSize = EltSize;
6312 if (&Sem == &APFloat::x87DoubleExtended())
6313 FloatEltSize = 80;
6314 for (unsigned i = 0; i < NElts; i++) {
6315 llvm::APInt Elt;
6316 if (BigEndian)
6317 Elt = SValInt.rotl(i*EltSize+FloatEltSize).trunc(FloatEltSize);
6318 else
6319 Elt = SValInt.rotr(i*EltSize).trunc(FloatEltSize);
6320 Elts.push_back(APValue(APFloat(Sem, Elt)));
6321 }
6322 } else if (EltTy->isIntegerType()) {
6323 for (unsigned i = 0; i < NElts; i++) {
6324 llvm::APInt Elt;
6325 if (BigEndian)
6326 Elt = SValInt.rotl(i*EltSize+EltSize).zextOrTrunc(EltSize);
6327 else
6328 Elt = SValInt.rotr(i*EltSize).zextOrTrunc(EltSize);
6329 Elts.push_back(APValue(APSInt(Elt, EltTy->isSignedIntegerType())));
6330 }
6331 } else {
6332 return Error(E);
6333 }
6334 return Success(Elts, E);
6335 }
6336 default:
6337 return ExprEvaluatorBaseTy::VisitCastExpr(E);
6338 }
6339}
6340
6341bool
6342VectorExprEvaluator::VisitInitListExpr(const InitListExpr *E) {
6343 const VectorType *VT = E->getType()->castAs<VectorType>();
6344 unsigned NumInits = E->getNumInits();
6345 unsigned NumElements = VT->getNumElements();
6346
6347 QualType EltTy = VT->getElementType();
6348 SmallVector<APValue, 4> Elements;
6349
6350 // The number of initializers can be less than the number of
6351 // vector elements. For OpenCL, this can be due to nested vector
6352 // initialization. For GCC compatibility, missing trailing elements
6353 // should be initialized with zeroes.
6354 unsigned CountInits = 0, CountElts = 0;
6355 while (CountElts < NumElements) {
6356 // Handle nested vector initialization.
6357 if (CountInits < NumInits
6358 && E->getInit(CountInits)->getType()->isVectorType()) {
6359 APValue v;
6360 if (!EvaluateVector(E->getInit(CountInits), v, Info))
6361 return Error(E);
6362 unsigned vlen = v.getVectorLength();
6363 for (unsigned j = 0; j < vlen; j++)
6364 Elements.push_back(v.getVectorElt(j));
6365 CountElts += vlen;
6366 } else if (EltTy->isIntegerType()) {
6367 llvm::APSInt sInt(32);
6368 if (CountInits < NumInits) {
6369 if (!EvaluateInteger(E->getInit(CountInits), sInt, Info))
6370 return false;
6371 } else // trailing integer zero.
6372 sInt = Info.Ctx.MakeIntValue(0, EltTy);
6373 Elements.push_back(APValue(sInt));
6374 CountElts++;
6375 } else {
6376 llvm::APFloat f(0.0);
6377 if (CountInits < NumInits) {
6378 if (!EvaluateFloat(E->getInit(CountInits), f, Info))
6379 return false;
6380 } else // trailing float zero.
6381 f = APFloat::getZero(Info.Ctx.getFloatTypeSemantics(EltTy));
6382 Elements.push_back(APValue(f));
6383 CountElts++;
6384 }
6385 CountInits++;
6386 }
6387 return Success(Elements, E);
6388}
6389
6390bool
6391VectorExprEvaluator::ZeroInitialization(const Expr *E) {
6392 const VectorType *VT = E->getType()->getAs<VectorType>();
6393 QualType EltTy = VT->getElementType();
6394 APValue ZeroElement;
6395 if (EltTy->isIntegerType())
6396 ZeroElement = APValue(Info.Ctx.MakeIntValue(0, EltTy));
6397 else
6398 ZeroElement =
6399 APValue(APFloat::getZero(Info.Ctx.getFloatTypeSemantics(EltTy)));
6400
6401 SmallVector<APValue, 4> Elements(VT->getNumElements(), ZeroElement);
6402 return Success(Elements, E);
6403}
6404
6405bool VectorExprEvaluator::VisitUnaryImag(const UnaryOperator *E) {
6406 VisitIgnoredValue(E->getSubExpr());
6407 return ZeroInitialization(E);
6408}
6409
6410//===----------------------------------------------------------------------===//
6411// Array Evaluation
6412//===----------------------------------------------------------------------===//
6413
6414namespace {
6415 class ArrayExprEvaluator
6416 : public ExprEvaluatorBase<ArrayExprEvaluator> {
6417 const LValue &This;
6418 APValue &Result;
6419 public:
6420
6421 ArrayExprEvaluator(EvalInfo &Info, const LValue &This, APValue &Result)
6422 : ExprEvaluatorBaseTy(Info), This(This), Result(Result) {}
6423
6424 bool Success(const APValue &V, const Expr *E) {
6425 assert((V.isArray() || V.isLValue()) &&(((V.isArray() || V.isLValue()) && "expected array or string literal"
) ? static_cast<void> (0) : __assert_fail ("(V.isArray() || V.isLValue()) && \"expected array or string literal\""
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 6426, __PRETTY_FUNCTION__))
6426 "expected array or string literal")(((V.isArray() || V.isLValue()) && "expected array or string literal"
) ? static_cast<void> (0) : __assert_fail ("(V.isArray() || V.isLValue()) && \"expected array or string literal\""
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 6426, __PRETTY_FUNCTION__))
;
6427 Result = V;
6428 return true;
6429 }
6430
6431 bool ZeroInitialization(const Expr *E) {
6432 const ConstantArrayType *CAT =
6433 Info.Ctx.getAsConstantArrayType(E->getType());
6434 if (!CAT)
6435 return Error(E);
6436
6437 Result = APValue(APValue::UninitArray(), 0,
6438 CAT->getSize().getZExtValue());
6439 if (!Result.hasArrayFiller()) return true;
6440
6441 // Zero-initialize all elements.
6442 LValue Subobject = This;
6443 Subobject.addArray(Info, E, CAT);
6444 ImplicitValueInitExpr VIE(CAT->getElementType());
6445 return EvaluateInPlace(Result.getArrayFiller(), Info, Subobject, &VIE);
6446 }
6447
6448 bool VisitCallExpr(const CallExpr *E) {
6449 return handleCallExpr(E, Result, &This);
6450 }
6451 bool VisitInitListExpr(const InitListExpr *E);
6452 bool VisitArrayInitLoopExpr(const ArrayInitLoopExpr *E);
6453 bool VisitCXXConstructExpr(const CXXConstructExpr *E);
6454 bool VisitCXXConstructExpr(const CXXConstructExpr *E,
6455 const LValue &Subobject,
6456 APValue *Value, QualType Type);
6457 };
6458} // end anonymous namespace
6459
6460static bool EvaluateArray(const Expr *E, const LValue &This,
6461 APValue &Result, EvalInfo &Info) {
6462 assert(E->isRValue() && E->getType()->isArrayType() && "not an array rvalue")((E->isRValue() && E->getType()->isArrayType
() && "not an array rvalue") ? static_cast<void>
(0) : __assert_fail ("E->isRValue() && E->getType()->isArrayType() && \"not an array rvalue\""
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 6462, __PRETTY_FUNCTION__))
;
6463 return ArrayExprEvaluator(Info, This, Result).Visit(E);
6464}
6465
6466bool ArrayExprEvaluator::VisitInitListExpr(const InitListExpr *E) {
6467 const ConstantArrayType *CAT = Info.Ctx.getAsConstantArrayType(E->getType());
6468 if (!CAT)
1
Assuming 'CAT' is non-null
2
Taking false branch
6469 return Error(E);
6470
6471 // C++11 [dcl.init.string]p1: A char array [...] can be initialized by [...]
6472 // an appropriately-typed string literal enclosed in braces.
6473 if (E->isStringLiteralInit()) {
3
Assuming the condition is false
4
Taking false branch
6474 LValue LV;
6475 if (!EvaluateLValue(E->getInit(0), LV, Info))
6476 return false;
6477 APValue Val;
6478 LV.moveInto(Val);
6479 return Success(Val, E);
6480 }
6481
6482 bool Success = true;
6483
6484 assert((!Result.isArray() || Result.getArrayInitializedElts() == 0) &&(((!Result.isArray() || Result.getArrayInitializedElts() == 0
) && "zero-initialized array shouldn't have any initialized elts"
) ? static_cast<void> (0) : __assert_fail ("(!Result.isArray() || Result.getArrayInitializedElts() == 0) && \"zero-initialized array shouldn't have any initialized elts\""
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 6485, __PRETTY_FUNCTION__))
6485 "zero-initialized array shouldn't have any initialized elts")(((!Result.isArray() || Result.getArrayInitializedElts() == 0
) && "zero-initialized array shouldn't have any initialized elts"
) ? static_cast<void> (0) : __assert_fail ("(!Result.isArray() || Result.getArrayInitializedElts() == 0) && \"zero-initialized array shouldn't have any initialized elts\""
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 6485, __PRETTY_FUNCTION__))
;
6486 APValue Filler;
6487 if (Result.isArray() && Result.hasArrayFiller())
6488 Filler = Result.getArrayFiller();
6489
6490 unsigned NumEltsToInit = E->getNumInits();
6491 unsigned NumElts = CAT->getSize().getZExtValue();
6492 const Expr *FillerExpr = E->hasArrayFiller() ? E->getArrayFiller() : nullptr;
5
Assuming the condition is false
6
'?' condition is false
7
'FillerExpr' initialized to a null pointer value
6493
6494 // If the initializer might depend on the array index, run it for each
6495 // array element. For now, just whitelist non-class value-initialization.
6496 if (NumEltsToInit != NumElts && !isa<ImplicitValueInitExpr>(FillerExpr))
6497 NumEltsToInit = NumElts;
6498
6499 Result = APValue(APValue::UninitArray(), NumEltsToInit, NumElts);
6500
6501 // If the array was previously zero-initialized, preserve the
6502 // zero-initialized values.
6503 if (!Filler.isUninit()) {
8
Taking false branch
6504 for (unsigned I = 0, E = Result.getArrayInitializedElts(); I != E; ++I)
6505 Result.getArrayInitializedElt(I) = Filler;
6506 if (Result.hasArrayFiller())
6507 Result.getArrayFiller() = Filler;
6508 }
6509
6510 LValue Subobject = This;
6511 Subobject.addArray(Info, E, CAT);
6512 for (unsigned Index = 0; Index != NumEltsToInit; ++Index) {
9
Assuming 'Index' is not equal to 'NumEltsToInit'
10
Loop condition is true. Entering loop body
6513 const Expr *Init =
13
'Init' initialized to a null pointer value
6514 Index < E->getNumInits() ? E->getInit(Index) : FillerExpr;
11
Assuming the condition is false
12
'?' condition is false
6515 if (!EvaluateInPlace(Result.getArrayInitializedElt(Index),
15
Calling 'EvaluateInPlace'
6516 Info, Subobject, Init) ||
14
Passing null pointer value via 4th parameter 'E'
6517 !HandleLValueArrayAdjustment(Info, Init, Subobject,
6518 CAT->getElementType(), 1)) {
6519 if (!Info.noteFailure())
6520 return false;
6521 Success = false;
6522 }
6523 }
6524
6525 if (!Result.hasArrayFiller())
6526 return Success;
6527
6528 // If we get here, we have a trivial filler, which we can just evaluate
6529 // once and splat over the rest of the array elements.
6530 assert(FillerExpr && "no array filler for incomplete init list")((FillerExpr && "no array filler for incomplete init list"
) ? static_cast<void> (0) : __assert_fail ("FillerExpr && \"no array filler for incomplete init list\""
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 6530, __PRETTY_FUNCTION__))
;
6531 return EvaluateInPlace(Result.getArrayFiller(), Info, Subobject,
6532 FillerExpr) && Success;
6533}
6534
6535bool ArrayExprEvaluator::VisitArrayInitLoopExpr(const ArrayInitLoopExpr *E) {
6536 if (E->getCommonExpr() &&
6537 !Evaluate(Info.CurrentCall->createTemporary(E->getCommonExpr(), false),
6538 Info, E->getCommonExpr()->getSourceExpr()))
6539 return false;
6540
6541 auto *CAT = cast<ConstantArrayType>(E->getType()->castAsArrayTypeUnsafe());
6542
6543 uint64_t Elements = CAT->getSize().getZExtValue();
6544 Result = APValue(APValue::UninitArray(), Elements, Elements);
6545
6546 LValue Subobject = This;
6547 Subobject.addArray(Info, E, CAT);
6548
6549 bool Success = true;
6550 for (EvalInfo::ArrayInitLoopIndex Index(Info); Index != Elements; ++Index) {
6551 if (!EvaluateInPlace(Result.getArrayInitializedElt(Index),
6552 Info, Subobject, E->getSubExpr()) ||
6553 !HandleLValueArrayAdjustment(Info, E, Subobject,
6554 CAT->getElementType(), 1)) {
6555 if (!Info.noteFailure())
6556 return false;
6557 Success = false;
6558 }
6559 }
6560
6561 return Success;
6562}
6563
6564bool ArrayExprEvaluator::VisitCXXConstructExpr(const CXXConstructExpr *E) {
6565 return VisitCXXConstructExpr(E, This, &Result, E->getType());
6566}
6567
6568bool ArrayExprEvaluator::VisitCXXConstructExpr(const CXXConstructExpr *E,
6569 const LValue &Subobject,
6570 APValue *Value,
6571 QualType Type) {
6572 bool HadZeroInit = !Value->isUninit();
6573
6574 if (const ConstantArrayType *CAT = Info.Ctx.getAsConstantArrayType(Type)) {
6575 unsigned N = CAT->getSize().getZExtValue();
6576
6577 // Preserve the array filler if we had prior zero-initialization.
6578 APValue Filler =
6579 HadZeroInit && Value->hasArrayFiller() ? Value->getArrayFiller()
6580 : APValue();
6581
6582 *Value = APValue(APValue::UninitArray(), N, N);
6583
6584 if (HadZeroInit)
6585 for (unsigned I = 0; I != N; ++I)
6586 Value->getArrayInitializedElt(I) = Filler;
6587
6588 // Initialize the elements.
6589 LValue ArrayElt = Subobject;
6590 ArrayElt.addArray(Info, E, CAT);
6591 for (unsigned I = 0; I != N; ++I)
6592 if (!VisitCXXConstructExpr(E, ArrayElt, &Value->getArrayInitializedElt(I),
6593 CAT->getElementType()) ||
6594 !HandleLValueArrayAdjustment(Info, E, ArrayElt,
6595 CAT->getElementType(), 1))
6596 return false;
6597
6598 return true;
6599 }
6600
6601 if (!Type->isRecordType())
6602 return Error(E);
6603
6604 return RecordExprEvaluator(Info, Subobject, *Value)
6605 .VisitCXXConstructExpr(E, Type);
6606}
6607
6608//===----------------------------------------------------------------------===//
6609// Integer Evaluation
6610//
6611// As a GNU extension, we support casting pointers to sufficiently-wide integer
6612// types and back in constant folding. Integer values are thus represented
6613// either as an integer-valued APValue, or as an lvalue-valued APValue.
6614//===----------------------------------------------------------------------===//
6615
6616namespace {
6617class IntExprEvaluator
6618 : public ExprEvaluatorBase<IntExprEvaluator> {
6619 APValue &Result;
6620public:
6621 IntExprEvaluator(EvalInfo &info, APValue &result)
6622 : ExprEvaluatorBaseTy(info), Result(result) {}
6623
6624 bool Success(const llvm::APSInt &SI, const Expr *E, APValue &Result) {
6625 assert(E->getType()->isIntegralOrEnumerationType() &&((E->getType()->isIntegralOrEnumerationType() &&
"Invalid evaluation result.") ? static_cast<void> (0) :
__assert_fail ("E->getType()->isIntegralOrEnumerationType() && \"Invalid evaluation result.\""
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 6626, __PRETTY_FUNCTION__))
6626 "Invalid evaluation result.")((E->getType()->isIntegralOrEnumerationType() &&
"Invalid evaluation result.") ? static_cast<void> (0) :
__assert_fail ("E->getType()->isIntegralOrEnumerationType() && \"Invalid evaluation result.\""
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 6626, __PRETTY_FUNCTION__))
;
6627 assert(SI.isSigned() == E->getType()->isSignedIntegerOrEnumerationType() &&((SI.isSigned() == E->getType()->isSignedIntegerOrEnumerationType
() && "Invalid evaluation result.") ? static_cast<
void> (0) : __assert_fail ("SI.isSigned() == E->getType()->isSignedIntegerOrEnumerationType() && \"Invalid evaluation result.\""
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 6628, __PRETTY_FUNCTION__))
6628 "Invalid evaluation result.")((SI.isSigned() == E->getType()->isSignedIntegerOrEnumerationType
() && "Invalid evaluation result.") ? static_cast<
void> (0) : __assert_fail ("SI.isSigned() == E->getType()->isSignedIntegerOrEnumerationType() && \"Invalid evaluation result.\""
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 6628, __PRETTY_FUNCTION__))
;
6629 assert(SI.getBitWidth() == Info.Ctx.getIntWidth(E->getType()) &&((SI.getBitWidth() == Info.Ctx.getIntWidth(E->getType()) &&
"Invalid evaluation result.") ? static_cast<void> (0) :
__assert_fail ("SI.getBitWidth() == Info.Ctx.getIntWidth(E->getType()) && \"Invalid evaluation result.\""
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 6630, __PRETTY_FUNCTION__))
6630 "Invalid evaluation result.")((SI.getBitWidth() == Info.Ctx.getIntWidth(E->getType()) &&
"Invalid evaluation result.") ? static_cast<void> (0) :
__assert_fail ("SI.getBitWidth() == Info.Ctx.getIntWidth(E->getType()) && \"Invalid evaluation result.\""
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 6630, __PRETTY_FUNCTION__))
;
6631 Result = APValue(SI);
6632 return true;
6633 }
6634 bool Success(const llvm::APSInt &SI, const Expr *E) {
6635 return Success(SI, E, Result);
6636 }
6637
6638 bool Success(const llvm::APInt &I, const Expr *E, APValue &Result) {
6639 assert(E->getType()->isIntegralOrEnumerationType() &&((E->getType()->isIntegralOrEnumerationType() &&
"Invalid evaluation result.") ? static_cast<void> (0) :
__assert_fail ("E->getType()->isIntegralOrEnumerationType() && \"Invalid evaluation result.\""
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 6640, __PRETTY_FUNCTION__))
6640 "Invalid evaluation result.")((E->getType()->isIntegralOrEnumerationType() &&
"Invalid evaluation result.") ? static_cast<void> (0) :
__assert_fail ("E->getType()->isIntegralOrEnumerationType() && \"Invalid evaluation result.\""
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 6640, __PRETTY_FUNCTION__))
;
6641 assert(I.getBitWidth() == Info.Ctx.getIntWidth(E->getType()) &&((I.getBitWidth() == Info.Ctx.getIntWidth(E->getType()) &&
"Invalid evaluation result.") ? static_cast<void> (0) :
__assert_fail ("I.getBitWidth() == Info.Ctx.getIntWidth(E->getType()) && \"Invalid evaluation result.\""
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 6642, __PRETTY_FUNCTION__))
6642 "Invalid evaluation result.")((I.getBitWidth() == Info.Ctx.getIntWidth(E->getType()) &&
"Invalid evaluation result.") ? static_cast<void> (0) :
__assert_fail ("I.getBitWidth() == Info.Ctx.getIntWidth(E->getType()) && \"Invalid evaluation result.\""
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 6642, __PRETTY_FUNCTION__))
;
6643 Result = APValue(APSInt(I));
6644 Result.getInt().setIsUnsigned(
6645 E->getType()->isUnsignedIntegerOrEnumerationType());
6646 return true;
6647 }
6648 bool Success(const llvm::APInt &I, const Expr *E) {
6649 return Success(I, E, Result);
6650 }
6651
6652 bool Success(uint64_t Value, const Expr *E, APValue &Result) {
6653 assert(E->getType()->isIntegralOrEnumerationType() &&((E->getType()->isIntegralOrEnumerationType() &&
"Invalid evaluation result.") ? static_cast<void> (0) :
__assert_fail ("E->getType()->isIntegralOrEnumerationType() && \"Invalid evaluation result.\""
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 6654, __PRETTY_FUNCTION__))
6654 "Invalid evaluation result.")((E->getType()->isIntegralOrEnumerationType() &&
"Invalid evaluation result.") ? static_cast<void> (0) :
__assert_fail ("E->getType()->isIntegralOrEnumerationType() && \"Invalid evaluation result.\""
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 6654, __PRETTY_FUNCTION__))
;
6655 Result = APValue(Info.Ctx.MakeIntValue(Value, E->getType()));
6656 return true;
6657 }
6658 bool Success(uint64_t Value, const Expr *E) {
6659 return Success(Value, E, Result);
6660 }
6661
6662 bool Success(CharUnits Size, const Expr *E) {
6663 return Success(Size.getQuantity(), E);
6664 }
6665
6666 bool Success(const APValue &V, const Expr *E) {
6667 if (V.isLValue() || V.isAddrLabelDiff()) {
6668 Result = V;
6669 return true;
6670 }
6671 return Success(V.getInt(), E);
6672 }
6673
6674 bool ZeroInitialization(const Expr *E) { return Success(0, E); }
6675
6676 //===--------------------------------------------------------------------===//
6677 // Visitor Methods
6678 //===--------------------------------------------------------------------===//
6679
6680 bool VisitIntegerLiteral(const IntegerLiteral *E) {
6681 return Success(E->getValue(), E);
6682 }
6683 bool VisitCharacterLiteral(const CharacterLiteral *E) {
6684 return Success(E->getValue(), E);
6685 }
6686
6687 bool CheckReferencedDecl(const Expr *E, const Decl *D);
6688 bool VisitDeclRefExpr(const DeclRefExpr *E) {
6689 if (CheckReferencedDecl(E, E->getDecl()))
6690 return true;
6691
6692 return ExprEvaluatorBaseTy::VisitDeclRefExpr(E);
6693 }
6694 bool VisitMemberExpr(const MemberExpr *E) {
6695 if (CheckReferencedDecl(E, E->getMemberDecl())) {
6696 VisitIgnoredBaseExpression(E->getBase());
6697 return true;
6698 }
6699
6700 return ExprEvaluatorBaseTy::VisitMemberExpr(E);
6701 }
6702
6703 bool VisitCallExpr(const CallExpr *E);
6704 bool VisitBuiltinCallExpr(const CallExpr *E, unsigned BuiltinOp);
6705 bool VisitBinaryOperator(const BinaryOperator *E);
6706 bool VisitOffsetOfExpr(const OffsetOfExpr *E);
6707 bool VisitUnaryOperator(const UnaryOperator *E);
6708
6709 bool VisitCastExpr(const CastExpr* E);
6710 bool VisitUnaryExprOrTypeTraitExpr(const UnaryExprOrTypeTraitExpr *E);
6711
6712 bool VisitCXXBoolLiteralExpr(const CXXBoolLiteralExpr *E) {
6713 return Success(E->getValue(), E);
6714 }
6715
6716 bool VisitObjCBoolLiteralExpr(const ObjCBoolLiteralExpr *E) {
6717 return Success(E->getValue(), E);
6718 }
6719
6720 bool VisitArrayInitIndexExpr(const ArrayInitIndexExpr *E) {
6721 if (Info.ArrayInitIndex == uint64_t(-1)) {
6722 // We were asked to evaluate this subexpression independent of the
6723 // enclosing ArrayInitLoopExpr. We can't do that.
6724 Info.FFDiag(E);
6725 return false;
6726 }
6727 return Success(Info.ArrayInitIndex, E);
6728 }
6729
6730 // Note, GNU defines __null as an integer, not a pointer.
6731 bool VisitGNUNullExpr(const GNUNullExpr *E) {
6732 return ZeroInitialization(E);
6733 }
6734
6735 bool VisitTypeTraitExpr(const TypeTraitExpr *E) {
6736 return Success(E->getValue(), E);
6737 }
6738
6739 bool VisitArrayTypeTraitExpr(const ArrayTypeTraitExpr *E) {
6740 return Success(E->getValue(), E);
6741 }
6742
6743 bool VisitExpressionTraitExpr(const ExpressionTraitExpr *E) {
6744 return Success(E->getValue(), E);
6745 }
6746
6747 bool VisitUnaryReal(const UnaryOperator *E);
6748 bool VisitUnaryImag(const UnaryOperator *E);
6749
6750 bool VisitCXXNoexceptExpr(const CXXNoexceptExpr *E);
6751 bool VisitSizeOfPackExpr(const SizeOfPackExpr *E);
6752
6753 // FIXME: Missing: array subscript of vector, member of vector
6754};
6755} // end anonymous namespace
6756
6757/// EvaluateIntegerOrLValue - Evaluate an rvalue integral-typed expression, and
6758/// produce either the integer value or a pointer.
6759///
6760/// GCC has a heinous extension which folds casts between pointer types and
6761/// pointer-sized integral types. We support this by allowing the evaluation of
6762/// an integer rvalue to produce a pointer (represented as an lvalue) instead.
6763/// Some simple arithmetic on such values is supported (they are treated much
6764/// like char*).
6765static bool EvaluateIntegerOrLValue(const Expr *E, APValue &Result,
6766 EvalInfo &Info) {
6767 assert(E->isRValue() && E->getType()->isIntegralOrEnumerationType())((E->isRValue() && E->getType()->isIntegralOrEnumerationType
()) ? static_cast<void> (0) : __assert_fail ("E->isRValue() && E->getType()->isIntegralOrEnumerationType()"
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 6767, __PRETTY_FUNCTION__))
;
6768 return IntExprEvaluator(Info, Result).Visit(E);
6769}
6770
6771static bool EvaluateInteger(const Expr *E, APSInt &Result, EvalInfo &Info) {
6772 APValue Val;
6773 if (!EvaluateIntegerOrLValue(E, Val, Info))
6774 return false;
6775 if (!Val.isInt()) {
6776 // FIXME: It would be better to produce the diagnostic for casting
6777 // a pointer to an integer.
6778 Info.FFDiag(E, diag::note_invalid_subexpr_in_const_expr);
6779 return false;
6780 }
6781 Result = Val.getInt();
6782 return true;
6783}
6784
6785/// Check whether the given declaration can be directly converted to an integral
6786/// rvalue. If not, no diagnostic is produced; there are other things we can
6787/// try.
6788bool IntExprEvaluator::CheckReferencedDecl(const Expr* E, const Decl* D) {
6789 // Enums are integer constant exprs.
6790 if (const EnumConstantDecl *ECD = dyn_cast<EnumConstantDecl>(D)) {
6791 // Check for signedness/width mismatches between E type and ECD value.
6792 bool SameSign = (ECD->getInitVal().isSigned()
6793 == E->getType()->isSignedIntegerOrEnumerationType());
6794 bool SameWidth = (ECD->getInitVal().getBitWidth()
6795 == Info.Ctx.getIntWidth(E->getType()));
6796 if (SameSign && SameWidth)
6797 return Success(ECD->getInitVal(), E);
6798 else {
6799 // Get rid of mismatch (otherwise Success assertions will fail)
6800 // by computing a new value matching the type of E.
6801 llvm::APSInt Val = ECD->getInitVal();
6802 if (!SameSign)
6803 Val.setIsSigned(!ECD->getInitVal().isSigned());
6804 if (!SameWidth)
6805 Val = Val.extOrTrunc(Info.Ctx.getIntWidth(E->getType()));
6806 return Success(Val, E);
6807 }
6808 }
6809 return false;
6810}
6811
6812/// EvaluateBuiltinClassifyType - Evaluate __builtin_classify_type the same way
6813/// as GCC.
6814static int EvaluateBuiltinClassifyType(const CallExpr *E,
6815 const LangOptions &LangOpts) {
6816 // The following enum mimics the values returned by GCC.
6817 // FIXME: Does GCC differ between lvalue and rvalue references here?
6818 enum gcc_type_class {
6819 no_type_class = -1,
6820 void_type_class, integer_type_class, char_type_class,
6821 enumeral_type_class, boolean_type_class,
6822 pointer_type_class, reference_type_class, offset_type_class,
6823 real_type_class, complex_type_class,
6824 function_type_class, method_type_class,
6825 record_type_class, union_type_class,
6826 array_type_class, string_type_class,
6827 lang_type_class
6828 };
6829
6830 // If no argument was supplied, default to "no_type_class". This isn't
6831 // ideal, however it is what gcc does.
6832 if (E->getNumArgs() == 0)
6833 return no_type_class;
6834
6835 QualType CanTy = E->getArg(0)->getType().getCanonicalType();
6836 const BuiltinType *BT = dyn_cast<BuiltinType>(CanTy);
6837
6838 switch (CanTy->getTypeClass()) {
6839#define TYPE(ID, BASE)
6840#define DEPENDENT_TYPE(ID, BASE) case Type::ID:
6841#define NON_CANONICAL_TYPE(ID, BASE) case Type::ID:
6842#define NON_CANONICAL_UNLESS_DEPENDENT_TYPE(ID, BASE) case Type::ID:
6843#include "clang/AST/TypeNodes.def"
6844 llvm_unreachable("CallExpr::isBuiltinClassifyType(): unimplemented type")::llvm::llvm_unreachable_internal("CallExpr::isBuiltinClassifyType(): unimplemented type"
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 6844)
;
6845
6846 case Type::Builtin:
6847 switch (BT->getKind()) {
6848#define BUILTIN_TYPE(ID, SINGLETON_ID)
6849#define SIGNED_TYPE(ID, SINGLETON_ID) case BuiltinType::ID: return integer_type_class;
6850#define FLOATING_TYPE(ID, SINGLETON_ID) case BuiltinType::ID: return real_type_class;
6851#define PLACEHOLDER_TYPE(ID, SINGLETON_ID) case BuiltinType::ID: break;
6852#include "clang/AST/BuiltinTypes.def"
6853 case BuiltinType::Void:
6854 return void_type_class;
6855
6856 case BuiltinType::Bool:
6857 return boolean_type_class;
6858
6859 case BuiltinType::Char_U: // gcc doesn't appear to use char_type_class
6860 case BuiltinType::UChar:
6861 case BuiltinType::UShort:
6862 case BuiltinType::UInt:
6863 case BuiltinType::ULong:
6864 case BuiltinType::ULongLong:
6865 case BuiltinType::UInt128:
6866 return integer_type_class;
6867
6868 case BuiltinType::NullPtr:
6869 return pointer_type_class;
6870
6871 case BuiltinType::WChar_U:
6872 case BuiltinType::Char16:
6873 case BuiltinType::Char32:
6874 case BuiltinType::ObjCId:
6875 case BuiltinType::ObjCClass:
6876 case BuiltinType::ObjCSel:
6877#define IMAGE_TYPE(ImgType, Id, SingletonId, Access, Suffix) \
6878 case BuiltinType::Id:
6879#include "clang/Basic/OpenCLImageTypes.def"
6880 case BuiltinType::OCLSampler:
6881 case BuiltinType::OCLEvent:
6882 case BuiltinType::OCLClkEvent:
6883 case BuiltinType::OCLQueue:
6884 case BuiltinType::OCLNDRange:
6885 case BuiltinType::OCLReserveID:
6886 case BuiltinType::Dependent:
6887 llvm_unreachable("CallExpr::isBuiltinClassifyType(): unimplemented type")::llvm::llvm_unreachable_internal("CallExpr::isBuiltinClassifyType(): unimplemented type"
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 6887)
;
6888 };
6889
6890 case Type::Enum:
6891 return LangOpts.CPlusPlus ? enumeral_type_class : integer_type_class;
6892 break;
6893
6894 case Type::Pointer:
6895 return pointer_type_class;
6896 break;
6897
6898 case Type::MemberPointer:
6899 if (CanTy->isMemberDataPointerType())
6900 return offset_type_class;
6901 else {
6902 // We expect member pointers to be either data or function pointers,
6903 // nothing else.
6904 assert(CanTy->isMemberFunctionPointerType())((CanTy->isMemberFunctionPointerType()) ? static_cast<void
> (0) : __assert_fail ("CanTy->isMemberFunctionPointerType()"
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 6904, __PRETTY_FUNCTION__))
;
6905 return method_type_class;
6906 }
6907
6908 case Type::Complex:
6909 return complex_type_class;
6910
6911 case Type::FunctionNoProto:
6912 case Type::FunctionProto:
6913 return LangOpts.CPlusPlus ? function_type_class : pointer_type_class;
6914
6915 case Type::Record:
6916 if (const RecordType *RT = CanTy->getAs<RecordType>()) {
6917 switch (RT->getDecl()->getTagKind()) {
6918 case TagTypeKind::TTK_Struct:
6919 case TagTypeKind::TTK_Class:
6920 case TagTypeKind::TTK_Interface:
6921 return record_type_class;
6922
6923 case TagTypeKind::TTK_Enum:
6924 return LangOpts.CPlusPlus ? enumeral_type_class : integer_type_class;
6925
6926 case TagTypeKind::TTK_Union:
6927 return union_type_class;
6928 }
6929 }
6930 llvm_unreachable("CallExpr::isBuiltinClassifyType(): unimplemented type")::llvm::llvm_unreachable_internal("CallExpr::isBuiltinClassifyType(): unimplemented type"
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 6930)
;
6931
6932 case Type::ConstantArray:
6933 case Type::VariableArray:
6934 case Type::IncompleteArray:
6935 return LangOpts.CPlusPlus ? array_type_class : pointer_type_class;
6936
6937 case Type::BlockPointer:
6938 case Type::LValueReference:
6939 case Type::RValueReference:
6940 case Type::Vector:
6941 case Type::ExtVector:
6942 case Type::Auto:
6943 case Type::ObjCObject:
6944 case Type::ObjCInterface:
6945 case Type::ObjCObjectPointer:
6946 case Type::Pipe:
6947 case Type::Atomic:
6948 llvm_unreachable("CallExpr::isBuiltinClassifyType(): unimplemented type")::llvm::llvm_unreachable_internal("CallExpr::isBuiltinClassifyType(): unimplemented type"
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 6948)
;
6949 }
6950
6951 llvm_unreachable("CallExpr::isBuiltinClassifyType(): unimplemented type")::llvm::llvm_unreachable_internal("CallExpr::isBuiltinClassifyType(): unimplemented type"
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 6951)
;
6952}
6953
6954/// EvaluateBuiltinConstantPForLValue - Determine the result of
6955/// __builtin_constant_p when applied to the given lvalue.
6956///
6957/// An lvalue is only "constant" if it is a pointer or reference to the first
6958/// character of a string literal.
6959template<typename LValue>
6960static bool EvaluateBuiltinConstantPForLValue(const LValue &LV) {
6961 const Expr *E = LV.getLValueBase().template dyn_cast<const Expr*>();
6962 return E && isa<StringLiteral>(E) && LV.getLValueOffset().isZero();
6963}
6964
6965/// EvaluateBuiltinConstantP - Evaluate __builtin_constant_p as similarly to
6966/// GCC as we can manage.
6967static bool EvaluateBuiltinConstantP(ASTContext &Ctx, const Expr *Arg) {
6968 QualType ArgType = Arg->getType();
6969
6970 // __builtin_constant_p always has one operand. The rules which gcc follows
6971 // are not precisely documented, but are as follows:
6972 //
6973 // - If the operand is of integral, floating, complex or enumeration type,
6974 // and can be folded to a known value of that type, it returns 1.
6975 // - If the operand and can be folded to a pointer to the first character
6976 // of a string literal (or such a pointer cast to an integral type), it
6977 // returns 1.
6978 //
6979 // Otherwise, it returns 0.
6980 //
6981 // FIXME: GCC also intends to return 1 for literals of aggregate types, but
6982 // its support for this does not currently work.
6983 if (ArgType->isIntegralOrEnumerationType()) {
6984 Expr::EvalResult Result;
6985 if (!Arg->EvaluateAsRValue(Result, Ctx) || Result.HasSideEffects)
6986 return false;
6987
6988 APValue &V = Result.Val;
6989 if (V.getKind() == APValue::Int)
6990 return true;
6991 if (V.getKind() == APValue::LValue)
6992 return EvaluateBuiltinConstantPForLValue(V);
6993 } else if (ArgType->isFloatingType() || ArgType->isAnyComplexType()) {
6994 return Arg->isEvaluatable(Ctx);
6995 } else if (ArgType->isPointerType() || Arg->isGLValue()) {
6996 LValue LV;
6997 Expr::EvalStatus Status;
6998 EvalInfo Info(Ctx, Status, EvalInfo::EM_ConstantFold);
6999 if ((Arg->isGLValue() ? EvaluateLValue(Arg, LV, Info)
7000 : EvaluatePointer(Arg, LV, Info)) &&
7001 !Status.HasSideEffects)
7002 return EvaluateBuiltinConstantPForLValue(LV);
7003 }
7004
7005 // Anything else isn't considered to be sufficiently constant.
7006 return false;
7007}
7008
7009/// Retrieves the "underlying object type" of the given expression,
7010/// as used by __builtin_object_size.
7011static QualType getObjectType(APValue::LValueBase B) {
7012 if (const ValueDecl *D = B.dyn_cast<const ValueDecl*>()) {
7013 if (const VarDecl *VD = dyn_cast<VarDecl>(D))
7014 return VD->getType();
7015 } else if (const Expr *E = B.get<const Expr*>()) {
7016 if (isa<CompoundLiteralExpr>(E))
7017 return E->getType();
7018 }
7019
7020 return QualType();
7021}
7022
7023/// A more selective version of E->IgnoreParenCasts for
7024/// tryEvaluateBuiltinObjectSize. This ignores some casts/parens that serve only
7025/// to change the type of E.
7026/// Ex. For E = `(short*)((char*)(&foo))`, returns `&foo`
7027///
7028/// Always returns an RValue with a pointer representation.
7029static const Expr *ignorePointerCastsAndParens(const Expr *E) {
7030 assert(E->isRValue() && E->getType()->hasPointerRepresentation())((E->isRValue() && E->getType()->hasPointerRepresentation
()) ? static_cast<void> (0) : __assert_fail ("E->isRValue() && E->getType()->hasPointerRepresentation()"
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 7030, __PRETTY_FUNCTION__))
;
7031
7032 auto *NoParens = E->IgnoreParens();
7033 auto *Cast = dyn_cast<CastExpr>(NoParens);
7034 if (Cast == nullptr)
7035 return NoParens;
7036
7037 // We only conservatively allow a few kinds of casts, because this code is
7038 // inherently a simple solution that seeks to support the common case.
7039 auto CastKind = Cast->getCastKind();
7040 if (CastKind != CK_NoOp && CastKind != CK_BitCast &&
7041 CastKind != CK_AddressSpaceConversion)
7042 return NoParens;
7043
7044 auto *SubExpr = Cast->getSubExpr();
7045 if (!SubExpr->getType()->hasPointerRepresentation() || !SubExpr->isRValue())
7046 return NoParens;
7047 return ignorePointerCastsAndParens(SubExpr);
7048}
7049
7050/// Checks to see if the given LValue's Designator is at the end of the LValue's
7051/// record layout. e.g.
7052/// struct { struct { int a, b; } fst, snd; } obj;
7053/// obj.fst // no
7054/// obj.snd // yes
7055/// obj.fst.a // no
7056/// obj.fst.b // no
7057/// obj.snd.a // no
7058/// obj.snd.b // yes
7059///
7060/// Please note: this function is specialized for how __builtin_object_size
7061/// views "objects".
7062///
7063/// If this encounters an invalid RecordDecl, it will always return true.
7064static bool isDesignatorAtObjectEnd(const ASTContext &Ctx, const LValue &LVal) {
7065 assert(!LVal.Designator.Invalid)((!LVal.Designator.Invalid) ? static_cast<void> (0) : __assert_fail
("!LVal.Designator.Invalid", "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 7065, __PRETTY_FUNCTION__))
;
7066
7067 auto IsLastOrInvalidFieldDecl = [&Ctx](const FieldDecl *FD, bool &Invalid) {
7068 const RecordDecl *Parent = FD->getParent();
7069 Invalid = Parent->isInvalidDecl();
7070 if (Invalid || Parent->isUnion())
7071 return true;
7072 const ASTRecordLayout &Layout = Ctx.getASTRecordLayout(Parent);
7073 return FD->getFieldIndex() + 1 == Layout.getFieldCount();
7074 };
7075
7076 auto &Base = LVal.getLValueBase();
7077 if (auto *ME = dyn_cast_or_null<MemberExpr>(Base.dyn_cast<const Expr *>())) {
7078 if (auto *FD = dyn_cast<FieldDecl>(ME->getMemberDecl())) {
7079 bool Invalid;
7080 if (!IsLastOrInvalidFieldDecl(FD, Invalid))
7081 return Invalid;
7082 } else if (auto *IFD = dyn_cast<IndirectFieldDecl>(ME->getMemberDecl())) {
7083 for (auto *FD : IFD->chain()) {
7084 bool Invalid;
7085 if (!IsLastOrInvalidFieldDecl(cast<FieldDecl>(FD), Invalid))
7086 return Invalid;
7087 }
7088 }
7089 }
7090
7091 unsigned I = 0;
7092 QualType BaseType = getType(Base);
7093 if (LVal.Designator.FirstEntryIsAnUnsizedArray) {
7094 assert(isBaseAnAllocSizeCall(Base) &&((isBaseAnAllocSizeCall(Base) && "Unsized array in non-alloc_size call?"
) ? static_cast<void> (0) : __assert_fail ("isBaseAnAllocSizeCall(Base) && \"Unsized array in non-alloc_size call?\""
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 7095, __PRETTY_FUNCTION__))
7095 "Unsized array in non-alloc_size call?")((isBaseAnAllocSizeCall(Base) && "Unsized array in non-alloc_size call?"
) ? static_cast<void> (0) : __assert_fail ("isBaseAnAllocSizeCall(Base) && \"Unsized array in non-alloc_size call?\""
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 7095, __PRETTY_FUNCTION__))
;
7096 // If this is an alloc_size base, we should ignore the initial array index
7097 ++I;
7098 BaseType = BaseType->castAs<PointerType>()->getPointeeType();
7099 }
7100
7101 for (unsigned E = LVal.Designator.Entries.size(); I != E; ++I) {
7102 const auto &Entry = LVal.Designator.Entries[I];
7103 if (BaseType->isArrayType()) {
7104 // Because __builtin_object_size treats arrays as objects, we can ignore
7105 // the index iff this is the last array in the Designator.
7106 if (I + 1 == E)
7107 return true;
7108 const auto *CAT = cast<ConstantArrayType>(Ctx.getAsArrayType(BaseType));
7109 uint64_t Index = Entry.ArrayIndex;
7110 if (Index + 1 != CAT->getSize())
7111 return false;
7112 BaseType = CAT->getElementType();
7113 } else if (BaseType->isAnyComplexType()) {
7114 const auto *CT = BaseType->castAs<ComplexType>();
7115 uint64_t Index = Entry.ArrayIndex;
7116 if (Index != 1)
7117 return false;
7118 BaseType = CT->getElementType();
7119 } else if (auto *FD = getAsField(Entry)) {
7120 bool Invalid;
7121 if (!IsLastOrInvalidFieldDecl(FD, Invalid))
7122 return Invalid;
7123 BaseType = FD->getType();
7124 } else {
7125 assert(getAsBaseClass(Entry) && "Expecting cast to a base class")((getAsBaseClass(Entry) && "Expecting cast to a base class"
) ? static_cast<void> (0) : __assert_fail ("getAsBaseClass(Entry) && \"Expecting cast to a base class\""
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 7125, __PRETTY_FUNCTION__))
;
7126 return false;
7127 }
7128 }
7129 return true;
7130}
7131
7132/// Tests to see if the LValue has a user-specified designator (that isn't
7133/// necessarily valid). Note that this always returns 'true' if the LValue has
7134/// an unsized array as its first designator entry, because there's currently no
7135/// way to tell if the user typed *foo or foo[0].
7136static bool refersToCompleteObject(const LValue &LVal) {
7137 if (LVal.Designator.Invalid)
7138 return false;
7139
7140 if (!LVal.Designator.Entries.empty())
7141 return LVal.Designator.isMostDerivedAnUnsizedArray();
7142
7143 if (!LVal.InvalidBase)
7144 return true;
7145
7146 // If `E` is a MemberExpr, then the first part of the designator is hiding in
7147 // the LValueBase.
7148 const auto *E = LVal.Base.dyn_cast<const Expr *>();
7149 return !E || !isa<MemberExpr>(E);
7150}
7151
7152/// Attempts to detect a user writing into a piece of memory that's impossible
7153/// to figure out the size of by just using types.
7154static bool isUserWritingOffTheEnd(const ASTContext &Ctx, const LValue &LVal) {
7155 const SubobjectDesignator &Designator = LVal.Designator;
7156 // Notes:
7157 // - Users can only write off of the end when we have an invalid base. Invalid
7158 // bases imply we don't know where the memory came from.
7159 // - We used to be a bit more aggressive here; we'd only be conservative if
7160 // the array at the end was flexible, or if it had 0 or 1 elements. This
7161 // broke some common standard library extensions (PR30346), but was
7162 // otherwise seemingly fine. It may be useful to reintroduce this behavior
7163 // with some sort of whitelist. OTOH, it seems that GCC is always
7164 // conservative with the last element in structs (if it's an array), so our
7165 // current behavior is more compatible than a whitelisting approach would
7166 // be.
7167 return LVal.InvalidBase &&
7168 Designator.Entries.size() == Designator.MostDerivedPathLength &&
7169 Designator.MostDerivedIsArrayElement &&
7170 isDesignatorAtObjectEnd(Ctx, LVal);
7171}
7172
7173/// Converts the given APInt to CharUnits, assuming the APInt is unsigned.
7174/// Fails if the conversion would cause loss of precision.
7175static bool convertUnsignedAPIntToCharUnits(const llvm::APInt &Int,
7176 CharUnits &Result) {
7177 auto CharUnitsMax = std::numeric_limits<CharUnits::QuantityType>::max();
7178 if (Int.ugt(CharUnitsMax))
7179 return false;
7180 Result = CharUnits::fromQuantity(Int.getZExtValue());
7181 return true;
7182}
7183
7184/// Helper for tryEvaluateBuiltinObjectSize -- Given an LValue, this will
7185/// determine how many bytes exist from the beginning of the object to either
7186/// the end of the current subobject, or the end of the object itself, depending
7187/// on what the LValue looks like + the value of Type.
7188///
7189/// If this returns false, the value of Result is undefined.
7190static bool determineEndOffset(EvalInfo &Info, SourceLocation ExprLoc,
7191 unsigned Type, const LValue &LVal,
7192 CharUnits &EndOffset) {
7193 bool DetermineForCompleteObject = refersToCompleteObject(LVal);
7194
7195 // We want to evaluate the size of the entire object. This is a valid fallback
7196 // for when Type=1 and the designator is invalid, because we're asked for an
7197 // upper-bound.
7198 if (!(Type & 1) || LVal.Designator.Invalid || DetermineForCompleteObject) {
7199 // Type=3 wants a lower bound, so we can't fall back to this.
7200 if (Type == 3 && !DetermineForCompleteObject)
7201 return false;
7202
7203 llvm::APInt APEndOffset;
7204 if (isBaseAnAllocSizeCall(LVal.getLValueBase()) &&
7205 getBytesReturnedByAllocSizeCall(Info.Ctx, LVal, APEndOffset))
7206 return convertUnsignedAPIntToCharUnits(APEndOffset, EndOffset);
7207
7208 if (LVal.InvalidBase)
7209 return false;
7210
7211 QualType BaseTy = getObjectType(LVal.getLValueBase());
7212 return !BaseTy.isNull() && HandleSizeof(Info, ExprLoc, BaseTy, EndOffset);
7213 }
7214
7215 // We want to evaluate the size of a subobject.
7216 const SubobjectDesignator &Designator = LVal.Designator;
7217
7218 // The following is a moderately common idiom in C:
7219 //
7220 // struct Foo { int a; char c[1]; };
7221 // struct Foo *F = (struct Foo *)malloc(sizeof(struct Foo) + strlen(Bar));
7222 // strcpy(&F->c[0], Bar);
7223 //
7224 // In order to not break too much legacy code, we need to support it.
7225 if (isUserWritingOffTheEnd(Info.Ctx, LVal)) {
7226 // If we can resolve this to an alloc_size call, we can hand that back,
7227 // because we know for certain how many bytes there are to write to.
7228 llvm::APInt APEndOffset;
7229 if (isBaseAnAllocSizeCall(LVal.getLValueBase()) &&
7230 getBytesReturnedByAllocSizeCall(Info.Ctx, LVal, APEndOffset))
7231 return convertUnsignedAPIntToCharUnits(APEndOffset, EndOffset);
7232
7233 // If we cannot determine the size of the initial allocation, then we can't
7234 // given an accurate upper-bound. However, we are still able to give
7235 // conservative lower-bounds for Type=3.
7236 if (Type == 1)
7237 return false;
7238 }
7239
7240 CharUnits BytesPerElem;
7241 if (!HandleSizeof(Info, ExprLoc, Designator.MostDerivedType, BytesPerElem))
7242 return false;
7243
7244 // According to the GCC documentation, we want the size of the subobject
7245 // denoted by the pointer. But that's not quite right -- what we actually
7246 // want is the size of the immediately-enclosing array, if there is one.
7247 int64_t ElemsRemaining;
7248 if (Designator.MostDerivedIsArrayElement &&
7249 Designator.Entries.size() == Designator.MostDerivedPathLength) {
7250 uint64_t ArraySize = Designator.getMostDerivedArraySize();
7251 uint64_t ArrayIndex = Designator.Entries.back().ArrayIndex;
7252 ElemsRemaining = ArraySize <= ArrayIndex ? 0 : ArraySize - ArrayIndex;
7253 } else {
7254 ElemsRemaining = Designator.isOnePastTheEnd() ? 0 : 1;
7255 }
7256
7257 EndOffset = LVal.getLValueOffset() + BytesPerElem * ElemsRemaining;
7258 return true;
7259}
7260
7261/// \brief Tries to evaluate the __builtin_object_size for @p E. If successful,
7262/// returns true and stores the result in @p Size.
7263///
7264/// If @p WasError is non-null, this will report whether the failure to evaluate
7265/// is to be treated as an Error in IntExprEvaluator.
7266static bool tryEvaluateBuiltinObjectSize(const Expr *E, unsigned Type,
7267 EvalInfo &Info, uint64_t &Size) {
7268 // Determine the denoted object.
7269 LValue LVal;
7270 {
7271 // The operand of __builtin_object_size is never evaluated for side-effects.
7272 // If there are any, but we can determine the pointed-to object anyway, then
7273 // ignore the side-effects.
7274 SpeculativeEvaluationRAII SpeculativeEval(Info);
7275 FoldOffsetRAII Fold(Info);
7276
7277 if (E->isGLValue()) {
7278 // It's possible for us to be given GLValues if we're called via
7279 // Expr::tryEvaluateObjectSize.
7280 APValue RVal;
7281 if (!EvaluateAsRValue(Info, E, RVal))
7282 return false;
7283 LVal.setFrom(Info.Ctx, RVal);
7284 } else if (!EvaluatePointer(ignorePointerCastsAndParens(E), LVal, Info))
7285 return false;
7286 }
7287
7288 // If we point to before the start of the object, there are no accessible
7289 // bytes.
7290 if (LVal.getLValueOffset().isNegative()) {
7291 Size = 0;
7292 return true;
7293 }
7294
7295 CharUnits EndOffset;
7296 if (!determineEndOffset(Info, E->getExprLoc(), Type, LVal, EndOffset))
7297 return false;
7298
7299 // If we've fallen outside of the end offset, just pretend there's nothing to
7300 // write to/read from.
7301 if (EndOffset <= LVal.getLValueOffset())
7302 Size = 0;
7303 else
7304 Size = (EndOffset - LVal.getLValueOffset()).getQuantity();
7305 return true;
7306}
7307
7308bool IntExprEvaluator::VisitCallExpr(const CallExpr *E) {
7309 if (unsigned BuiltinOp = E->getBuiltinCallee())
7310 return VisitBuiltinCallExpr(E, BuiltinOp);
7311
7312 return ExprEvaluatorBaseTy::VisitCallExpr(E);
7313}
7314
7315bool IntExprEvaluator::VisitBuiltinCallExpr(const CallExpr *E,
7316 unsigned BuiltinOp) {
7317 switch (unsigned BuiltinOp = E->getBuiltinCallee()) {
7318 default:
7319 return ExprEvaluatorBaseTy::VisitCallExpr(E);
7320
7321 case Builtin::BI__builtin_object_size: {
7322 // The type was checked when we built the expression.
7323 unsigned Type =
7324 E->getArg(1)->EvaluateKnownConstInt(Info.Ctx).getZExtValue();
7325 assert(Type <= 3 && "unexpected type")((Type <= 3 && "unexpected type") ? static_cast<
void> (0) : __assert_fail ("Type <= 3 && \"unexpected type\""
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 7325, __PRETTY_FUNCTION__))
;
7326
7327 uint64_t Size;
7328 if (tryEvaluateBuiltinObjectSize(E->getArg(0), Type, Info, Size))
7329 return Success(Size, E);
7330
7331 if (E->getArg(0)->HasSideEffects(Info.Ctx))
7332 return Success((Type & 2) ? 0 : -1, E);
7333
7334 // Expression had no side effects, but we couldn't statically determine the
7335 // size of the referenced object.
7336 switch (Info.EvalMode) {
7337 case EvalInfo::EM_ConstantExpression:
7338 case EvalInfo::EM_PotentialConstantExpression:
7339 case EvalInfo::EM_ConstantFold:
7340 case EvalInfo::EM_EvaluateForOverflow:
7341 case EvalInfo::EM_IgnoreSideEffects:
7342 case EvalInfo::EM_OffsetFold:
7343 // Leave it to IR generation.
7344 return Error(E);
7345 case EvalInfo::EM_ConstantExpressionUnevaluated:
7346 case EvalInfo::EM_PotentialConstantExpressionUnevaluated:
7347 // Reduce it to a constant now.
7348 return Success((Type & 2) ? 0 : -1, E);
7349 }
7350
7351 llvm_unreachable("unexpected EvalMode")::llvm::llvm_unreachable_internal("unexpected EvalMode", "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 7351)
;
7352 }
7353
7354 case Builtin::BI__builtin_bswap16:
7355 case Builtin::BI__builtin_bswap32:
7356 case Builtin::BI__builtin_bswap64: {
7357 APSInt Val;
7358 if (!EvaluateInteger(E->getArg(0), Val, Info))
7359 return false;
7360
7361 return Success(Val.byteSwap(), E);
7362 }
7363
7364 case Builtin::BI__builtin_classify_type:
7365 return Success(EvaluateBuiltinClassifyType(E, Info.getLangOpts()), E);
7366
7367 // FIXME: BI__builtin_clrsb
7368 // FIXME: BI__builtin_clrsbl
7369 // FIXME: BI__builtin_clrsbll
7370
7371 case Builtin::BI__builtin_clz:
7372 case Builtin::BI__builtin_clzl:
7373 case Builtin::BI__builtin_clzll:
7374 case Builtin::BI__builtin_clzs: {
7375 APSInt Val;
7376 if (!EvaluateInteger(E->getArg(0), Val, Info))
7377 return false;
7378 if (!Val)
7379 return Error(E);
7380
7381 return Success(Val.countLeadingZeros(), E);
7382 }
7383
7384 case Builtin::BI__builtin_constant_p:
7385 return Success(EvaluateBuiltinConstantP(Info.Ctx, E->getArg(0)), E);
7386
7387 case Builtin::BI__builtin_ctz:
7388 case Builtin::BI__builtin_ctzl:
7389 case Builtin::BI__builtin_ctzll:
7390 case Builtin::BI__builtin_ctzs: {
7391 APSInt Val;
7392 if (!EvaluateInteger(E->getArg(0), Val, Info))
7393 return false;
7394 if (!Val)
7395 return Error(E);
7396
7397 return Success(Val.countTrailingZeros(), E);
7398 }
7399
7400 case Builtin::BI__builtin_eh_return_data_regno: {
7401 int Operand = E->getArg(0)->EvaluateKnownConstInt(Info.Ctx).getZExtValue();
7402 Operand = Info.Ctx.getTargetInfo().getEHDataRegisterNumber(Operand);
7403 return Success(Operand, E);
7404 }
7405
7406 case Builtin::BI__builtin_expect:
7407 return Visit(E->getArg(0));
7408
7409 case Builtin::BI__builtin_ffs:
7410 case Builtin::BI__builtin_ffsl:
7411 case Builtin::BI__builtin_ffsll: {
7412 APSInt Val;
7413 if (!EvaluateInteger(E->getArg(0), Val, Info))
7414 return false;
7415
7416 unsigned N = Val.countTrailingZeros();
7417 return Success(N == Val.getBitWidth() ? 0 : N + 1, E);
7418 }
7419
7420 case Builtin::BI__builtin_fpclassify: {
7421 APFloat Val(0.0);
7422 if (!EvaluateFloat(E->getArg(5), Val, Info))
7423 return false;
7424 unsigned Arg;
7425 switch (Val.getCategory()) {
7426 case APFloat::fcNaN: Arg = 0; break;
7427 case APFloat::fcInfinity: Arg = 1; break;
7428 case APFloat::fcNormal: Arg = Val.isDenormal() ? 3 : 2; break;
7429 case APFloat::fcZero: Arg = 4; break;
7430 }
7431 return Visit(E->getArg(Arg));
7432 }
7433
7434 case Builtin::BI__builtin_isinf_sign: {
7435 APFloat Val(0.0);
7436 return EvaluateFloat(E->getArg(0), Val, Info) &&
7437 Success(Val.isInfinity() ? (Val.isNegative() ? -1 : 1) : 0, E);
7438 }
7439
7440 case Builtin::BI__builtin_isinf: {
7441 APFloat Val(0.0);
7442 return EvaluateFloat(E->getArg(0), Val, Info) &&
7443 Success(Val.isInfinity() ? 1 : 0, E);
7444 }
7445
7446 case Builtin::BI__builtin_isfinite: {
7447 APFloat Val(0.0);
7448 return EvaluateFloat(E->getArg(0), Val, Info) &&
7449 Success(Val.isFinite() ? 1 : 0, E);
7450 }
7451
7452 case Builtin::BI__builtin_isnan: {
7453 APFloat Val(0.0);
7454 return EvaluateFloat(E->getArg(0), Val, Info) &&
7455 Success(Val.isNaN() ? 1 : 0, E);
7456 }
7457
7458 case Builtin::BI__builtin_isnormal: {
7459 APFloat Val(0.0);
7460 return EvaluateFloat(E->getArg(0), Val, Info) &&
7461 Success(Val.isNormal() ? 1 : 0, E);
7462 }
7463
7464 case Builtin::BI__builtin_parity:
7465 case Builtin::BI__builtin_parityl:
7466 case Builtin::BI__builtin_parityll: {
7467 APSInt Val;
7468 if (!EvaluateInteger(E->getArg(0), Val, Info))
7469 return false;
7470
7471 return Success(Val.countPopulation() % 2, E);
7472 }
7473
7474 case Builtin::BI__builtin_popcount:
7475 case Builtin::BI__builtin_popcountl:
7476 case Builtin::BI__builtin_popcountll: {
7477 APSInt Val;
7478 if (!EvaluateInteger(E->getArg(0), Val, Info))
7479 return false;
7480
7481 return Success(Val.countPopulation(), E);
7482 }
7483
7484 case Builtin::BIstrlen:
7485 case Builtin::BIwcslen:
7486 // A call to strlen is not a constant expression.
7487 if (Info.getLangOpts().CPlusPlus11)
7488 Info.CCEDiag(E, diag::note_constexpr_invalid_function)
7489 << /*isConstexpr*/0 << /*isConstructor*/0
7490 << (std::string("'") + Info.Ctx.BuiltinInfo.getName(BuiltinOp) + "'");
7491 else
7492 Info.CCEDiag(E, diag::note_invalid_subexpr_in_const_expr);
7493 // Fall through.
7494 case Builtin::BI__builtin_strlen:
7495 case Builtin::BI__builtin_wcslen: {
7496 // As an extension, we support __builtin_strlen() as a constant expression,
7497 // and support folding strlen() to a constant.
7498 LValue String;
7499 if (!EvaluatePointer(E->getArg(0), String, Info))
7500 return false;
7501
7502 QualType CharTy = E->getArg(0)->getType()->getPointeeType();
7503
7504 // Fast path: if it's a string literal, search the string value.
7505 if (const StringLiteral *S = dyn_cast_or_null<StringLiteral>(
7506 String.getLValueBase().dyn_cast<const Expr *>())) {
7507 // The string literal may have embedded null characters. Find the first
7508 // one and truncate there.
7509 StringRef Str = S->getBytes();
7510 int64_t Off = String.Offset.getQuantity();
7511 if (Off >= 0 && (uint64_t)Off <= (uint64_t)Str.size() &&
7512 S->getCharByteWidth() == 1 &&
7513 // FIXME: Add fast-path for wchar_t too.
7514 Info.Ctx.hasSameUnqualifiedType(CharTy, Info.Ctx.CharTy)) {
7515 Str = Str.substr(Off);
7516
7517 StringRef::size_type Pos = Str.find(0);
7518 if (Pos != StringRef::npos)
7519 Str = Str.substr(0, Pos);
7520
7521 return Success(Str.size(), E);
7522 }
7523
7524 // Fall through to slow path to issue appropriate diagnostic.
7525 }
7526
7527 // Slow path: scan the bytes of the string looking for the terminating 0.
7528 for (uint64_t Strlen = 0; /**/; ++Strlen) {
7529 APValue Char;
7530 if (!handleLValueToRValueConversion(Info, E, CharTy, String, Char) ||
7531 !Char.isInt())
7532 return false;
7533 if (!Char.getInt())
7534 return Success(Strlen, E);
7535 if (!HandleLValueArrayAdjustment(Info, E, String, CharTy, 1))
7536 return false;
7537 }
7538 }
7539
7540 case Builtin::BIstrcmp:
7541 case Builtin::BIwcscmp:
7542 case Builtin::BIstrncmp:
7543 case Builtin::BIwcsncmp:
7544 case Builtin::BImemcmp:
7545 case Builtin::BIwmemcmp:
7546 // A call to strlen is not a constant expression.
7547 if (Info.getLangOpts().CPlusPlus11)
7548 Info.CCEDiag(E, diag::note_constexpr_invalid_function)
7549 << /*isConstexpr*/0 << /*isConstructor*/0
7550 << (std::string("'") + Info.Ctx.BuiltinInfo.getName(BuiltinOp) + "'");
7551 else
7552 Info.CCEDiag(E, diag::note_invalid_subexpr_in_const_expr);
7553 // Fall through.
7554 case Builtin::BI__builtin_strcmp:
7555 case Builtin::BI__builtin_wcscmp:
7556 case Builtin::BI__builtin_strncmp:
7557 case Builtin::BI__builtin_wcsncmp:
7558 case Builtin::BI__builtin_memcmp:
7559 case Builtin::BI__builtin_wmemcmp: {
7560 LValue String1, String2;
7561 if (!EvaluatePointer(E->getArg(0), String1, Info) ||
7562 !EvaluatePointer(E->getArg(1), String2, Info))
7563 return false;
7564
7565 QualType CharTy = E->getArg(0)->getType()->getPointeeType();
7566
7567 uint64_t MaxLength = uint64_t(-1);
7568 if (BuiltinOp != Builtin::BIstrcmp &&
7569 BuiltinOp != Builtin::BIwcscmp &&
7570 BuiltinOp != Builtin::BI__builtin_strcmp &&
7571 BuiltinOp != Builtin::BI__builtin_wcscmp) {
7572 APSInt N;
7573 if (!EvaluateInteger(E->getArg(2), N, Info))
7574 return false;
7575 MaxLength = N.getExtValue();
7576 }
7577 bool StopAtNull = (BuiltinOp != Builtin::BImemcmp &&
7578 BuiltinOp != Builtin::BIwmemcmp &&
7579 BuiltinOp != Builtin::BI__builtin_memcmp &&
7580 BuiltinOp != Builtin::BI__builtin_wmemcmp);
7581 for (; MaxLength; --MaxLength) {
7582 APValue Char1, Char2;
7583 if (!handleLValueToRValueConversion(Info, E, CharTy, String1, Char1) ||
7584 !handleLValueToRValueConversion(Info, E, CharTy, String2, Char2) ||
7585 !Char1.isInt() || !Char2.isInt())
7586 return false;
7587 if (Char1.getInt() != Char2.getInt())
7588 return Success(Char1.getInt() < Char2.getInt() ? -1 : 1, E);
7589 if (StopAtNull && !Char1.getInt())
7590 return Success(0, E);
7591 assert(!(StopAtNull && !Char2.getInt()))((!(StopAtNull && !Char2.getInt())) ? static_cast<
void> (0) : __assert_fail ("!(StopAtNull && !Char2.getInt())"
, "/tmp/buildd/llvm-toolchain-snapshot-4.0~svn290870/tools/clang/lib/AST/ExprConstant.cpp"
, 7591, __PRETTY_FUNCTION__))
;
7592 if (!HandleLValueArrayAdjustment(Info, E, String1, CharTy, 1) ||
7593 !HandleLValueArrayAdjustment(Info, E, String2, CharTy, 1))
7594 return false;
7595 }
7596 // We hit the strncmp / memcmp limit.
7597 return Success(0, E);
7598 }
7599
7600 case Builtin::BI__atomic_always_lock_free:
7601 case Builtin::BI__atomic_is_lock_free:
7602 case Builtin::BI__c11_atomic_is_lock_free: {
7603 APSInt SizeVal;
7604 if (!EvaluateInteger(E->getArg(0), SizeVal, Info))
7605 return false;
7606
7607 // For __atomic_is_lock_free(sizeof(_Atomic(T))), if the size is a power
7608 // of two less than the maximum inline atomic width, we know it is
7609 // lock-free. If the size isn't a power of two, or greater than the
7610 // maximum alignment where we promote atomics, we know it is not lock-free
7611 // (at least not in the sense of atomic_is_lock_free). Otherwise,
7612 // the answer can only be determined at runtime; for example, 16-byte
7613 // atomics have lock-free implementations on some, but not all,
7614 // x86-64 processors.
7615
7616 // Check power-of-two.
7617 CharUnits Size = CharUnits::fromQuantity(SizeVal.getZExtValue());
7618 if (Size.isPowerOfTwo()) {
7619 // Check against inlining width.
7620 unsigned InlineWidthBits =
7621 Info.Ctx.getTargetInfo().getMaxAtomicInlineWidth();
7622 if (Size <= Info.Ctx.toCharUnitsFromBits(InlineWidthBits)) {
7623 if (BuiltinOp == Builtin::BI__c11_atomic_is_lock_free ||
7624 Size == CharUnits::One() ||
7625 E->getArg(1)->isNullPointerConstant(Info.Ctx,
7626 Expr::NPC_NeverValueDependent))
7627 // OK, we will inline appropriately-aligned operations of this size,
7628 // and _Atomic(T) is appropriately-aligned.
7629 return Success(1, E);
7630
7631 QualType PointeeType = E->getArg(1)->IgnoreImpCasts()->getType()->
7632 castAs<PointerType>()->getPointeeType();
7633 if (!PointeeType->isIncompleteType() &&
7634 Info.Ctx.getTypeAlignInChars(PointeeType) >= Size) {
7635 // OK, we will inline operations on this object.
7636 return Success(1, E);
7637 }
7638 }
7639 }
7640
7641 return BuiltinOp == Builtin::BI__atomic_always_lock_free ?
7642 Success(0, E) : Error(E);
7643 }
7644 }
7645}
7646
7647static bool HasSameBase(const LValue &A, const LValue &B) {
7648 if (!A.getLValueBase())
7649 return !B.getLValueBase();
7650 if (!B.getLValueBase())
7651 return false;
7652
7653 if (A.getLValueBase().getOpaqueValue() !=
7654 B.getLValueBase().getOpaqueValue()) {
7655 const Decl *ADecl = GetLValueBaseDecl(A);
7656 if (!ADecl)
7657 return false;
7658 const Decl *BDecl = GetLValueBaseDecl(B);
7659 if (!BDecl || ADecl->getCanonicalDecl() != BDecl->getCanonicalDecl())
7660 return false;
7661 }
7662
7663 return IsGlobalLValue(A.getLValueBase()) ||
7664 A.getLValueCallIndex() == B.getLValueCallIndex();
7665}
7666
7667/// \brief Determine whether this is a pointer past the end of the complete
7668/// object referred to by the lvalue.
7669static bool isOnePastTheEndOfCompleteObject(const ASTContext &Ctx,
7670 const LValue &LV) {
7671 // A null pointer can be viewed as being "past the end" but we don't
7672 // choose to look at it that way here.
7673 if (!LV.getLValueBase())
7674 return false;
7675
7676 // If the designator is valid and refers to a subobject, we're not pointing
7677 // past the end.
7678 if (!LV.getLValueDesignator().Invalid &&
7679 !LV.getLValueDesignator().isOnePastTheEnd())
7680 return false;
7681
7682 // A pointer to an incomplete type might be past-the-end if the type's size is
7683 // zero. We cannot tell because the type is incomplete.
7684 QualType Ty = getType(LV.getLValueBase());
7685 if (Ty->isIncompleteType())
7686 return true;
7687
7688 // We're a past-the-end pointer if we point to the byte after the object,
7689 // no matter what our type or path is.
7690 auto Size = Ctx.getTypeSizeInChars(Ty);
7691 return LV.getLValueOffset() == Size;
7692}
7693
7694namespace {
7695
7696/// \brief Data recursive integer evaluator of certain binary operators.
7697///
7698/// We use a data recursive algorithm for binary operators so that we are able
7699/// to handle extreme cases of chained binary operators without causing stack
7700/// overflow.
7701class DataRecursiveIntBinOpEvaluator {
7702 struct EvalResult {
7703 APValue Val;
7704 bool Failed;
7705
7706 EvalResult() : Failed(false) { }
7707
7708 void swap(EvalResult &RHS) {
7709 Val.swap(RHS.Val);
7710 Failed = RHS.Failed;
7711 RHS.Failed = false;
7712 }
7713 };
7714
7715 struct Job {
7716 const Expr *E;
7717 EvalResult LHSResult; // meaningful only for binary operator expression.
7718 enum { AnyExprKind, BinOpKind, BinOpVisitedLHSKind } Kind;
7719
7720 Job() = default;
7721 Job(Job &&) = default;
7722
7723 void startSpeculativeEval(EvalInfo &Info) {
7724 SpecEvalRAII = SpeculativeEvaluationRAII(Info);
7725 }
7726
7727 private:
7728 SpeculativeEvaluationRAII SpecEvalRAII;
7729 };
7730
7731 SmallVector<Job, 16> Queue;
7732
7733 IntExprEvaluator &IntEval;
7734 EvalInfo &Info;
7735 APValue &FinalResult;
7736
7737public:
7738 DataRecursiveIntBinOpEvaluator(IntExprEvaluator &IntEval, APValue &Result)
7739 : IntEval(IntEval), Info(IntEval.getEvalInfo()), FinalResult(Result) { }
7740
7741 /// \brief True if \param E is a binary operator that we are going to handle
7742 /// data recursively.
7743 /// We handle binary o