Bug Summary

File:clang/lib/Sema/SemaStmt.cpp
Warning:line 3617, column 9
Access to field 'CallOperator' results in a dereference of a null pointer (loaded from variable 'CurLambda')

Annotated Source Code

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clang -cc1 -cc1 -triple x86_64-pc-linux-gnu -analyze -disable-free -disable-llvm-verifier -discard-value-names -main-file-name SemaStmt.cpp -analyzer-store=region -analyzer-opt-analyze-nested-blocks -analyzer-checker=core -analyzer-checker=apiModeling -analyzer-checker=unix -analyzer-checker=deadcode -analyzer-checker=cplusplus -analyzer-checker=security.insecureAPI.UncheckedReturn -analyzer-checker=security.insecureAPI.getpw -analyzer-checker=security.insecureAPI.gets -analyzer-checker=security.insecureAPI.mktemp -analyzer-checker=security.insecureAPI.mkstemp -analyzer-checker=security.insecureAPI.vfork -analyzer-checker=nullability.NullPassedToNonnull -analyzer-checker=nullability.NullReturnedFromNonnull -analyzer-output plist -w -setup-static-analyzer -analyzer-config-compatibility-mode=true -mrelocation-model pic -pic-level 2 -mframe-pointer=none -relaxed-aliasing -fmath-errno -fno-rounding-math -mconstructor-aliases -munwind-tables -target-cpu x86-64 -tune-cpu generic -debugger-tuning=gdb -ffunction-sections -fdata-sections -fcoverage-compilation-dir=/build/llvm-toolchain-snapshot-14~++20210903100615+fd66b44ec19e/build-llvm/tools/clang/lib/Sema -resource-dir /usr/lib/llvm-14/lib/clang/14.0.0 -D _GNU_SOURCE -D __STDC_CONSTANT_MACROS -D __STDC_FORMAT_MACROS -D __STDC_LIMIT_MACROS -I /build/llvm-toolchain-snapshot-14~++20210903100615+fd66b44ec19e/build-llvm/tools/clang/lib/Sema -I /build/llvm-toolchain-snapshot-14~++20210903100615+fd66b44ec19e/clang/lib/Sema -I /build/llvm-toolchain-snapshot-14~++20210903100615+fd66b44ec19e/clang/include -I /build/llvm-toolchain-snapshot-14~++20210903100615+fd66b44ec19e/build-llvm/tools/clang/include -I /build/llvm-toolchain-snapshot-14~++20210903100615+fd66b44ec19e/build-llvm/include -I /build/llvm-toolchain-snapshot-14~++20210903100615+fd66b44ec19e/llvm/include -D NDEBUG -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/10/../../../../include/c++/10 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/10/../../../../include/x86_64-linux-gnu/c++/10 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/10/../../../../include/c++/10/backward -internal-isystem /usr/lib/llvm-14/lib/clang/14.0.0/include -internal-isystem /usr/local/include -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/10/../../../../x86_64-linux-gnu/include -internal-externc-isystem /usr/include/x86_64-linux-gnu -internal-externc-isystem /include -internal-externc-isystem /usr/include -O2 -Wno-unused-parameter -Wwrite-strings -Wno-missing-field-initializers -Wno-long-long -Wno-maybe-uninitialized -Wno-class-memaccess -Wno-redundant-move -Wno-pessimizing-move -Wno-noexcept-type -Wno-comment -std=c++14 -fdeprecated-macro -fdebug-compilation-dir=/build/llvm-toolchain-snapshot-14~++20210903100615+fd66b44ec19e/build-llvm/tools/clang/lib/Sema -fdebug-prefix-map=/build/llvm-toolchain-snapshot-14~++20210903100615+fd66b44ec19e=. -ferror-limit 19 -fvisibility-inlines-hidden -stack-protector 2 -fgnuc-version=4.2.1 -vectorize-loops -vectorize-slp -analyzer-output=html -analyzer-config stable-report-filename=true -faddrsig -D__GCC_HAVE_DWARF2_CFI_ASM=1 -o /tmp/scan-build-2021-09-04-040900-46481-1 -x c++ /build/llvm-toolchain-snapshot-14~++20210903100615+fd66b44ec19e/clang/lib/Sema/SemaStmt.cpp
1//===--- SemaStmt.cpp - Semantic Analysis for Statements ------------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// This file implements semantic analysis for statements.
10//
11//===----------------------------------------------------------------------===//
12
13#include "clang/AST/ASTContext.h"
14#include "clang/AST/ASTDiagnostic.h"
15#include "clang/AST/ASTLambda.h"
16#include "clang/AST/CXXInheritance.h"
17#include "clang/AST/CharUnits.h"
18#include "clang/AST/DeclObjC.h"
19#include "clang/AST/EvaluatedExprVisitor.h"
20#include "clang/AST/ExprCXX.h"
21#include "clang/AST/ExprObjC.h"
22#include "clang/AST/IgnoreExpr.h"
23#include "clang/AST/RecursiveASTVisitor.h"
24#include "clang/AST/StmtCXX.h"
25#include "clang/AST/StmtObjC.h"
26#include "clang/AST/TypeLoc.h"
27#include "clang/AST/TypeOrdering.h"
28#include "clang/Basic/TargetInfo.h"
29#include "clang/Lex/Preprocessor.h"
30#include "clang/Sema/Initialization.h"
31#include "clang/Sema/Lookup.h"
32#include "clang/Sema/Ownership.h"
33#include "clang/Sema/Scope.h"
34#include "clang/Sema/ScopeInfo.h"
35#include "clang/Sema/SemaInternal.h"
36#include "llvm/ADT/ArrayRef.h"
37#include "llvm/ADT/DenseMap.h"
38#include "llvm/ADT/STLExtras.h"
39#include "llvm/ADT/SmallPtrSet.h"
40#include "llvm/ADT/SmallString.h"
41#include "llvm/ADT/SmallVector.h"
42
43using namespace clang;
44using namespace sema;
45
46StmtResult Sema::ActOnExprStmt(ExprResult FE, bool DiscardedValue) {
47 if (FE.isInvalid())
48 return StmtError();
49
50 FE = ActOnFinishFullExpr(FE.get(), FE.get()->getExprLoc(), DiscardedValue);
51 if (FE.isInvalid())
52 return StmtError();
53
54 // C99 6.8.3p2: The expression in an expression statement is evaluated as a
55 // void expression for its side effects. Conversion to void allows any
56 // operand, even incomplete types.
57
58 // Same thing in for stmt first clause (when expr) and third clause.
59 return StmtResult(FE.getAs<Stmt>());
60}
61
62
63StmtResult Sema::ActOnExprStmtError() {
64 DiscardCleanupsInEvaluationContext();
65 return StmtError();
66}
67
68StmtResult Sema::ActOnNullStmt(SourceLocation SemiLoc,
69 bool HasLeadingEmptyMacro) {
70 return new (Context) NullStmt(SemiLoc, HasLeadingEmptyMacro);
71}
72
73StmtResult Sema::ActOnDeclStmt(DeclGroupPtrTy dg, SourceLocation StartLoc,
74 SourceLocation EndLoc) {
75 DeclGroupRef DG = dg.get();
76
77 // If we have an invalid decl, just return an error.
78 if (DG.isNull()) return StmtError();
79
80 return new (Context) DeclStmt(DG, StartLoc, EndLoc);
81}
82
83void Sema::ActOnForEachDeclStmt(DeclGroupPtrTy dg) {
84 DeclGroupRef DG = dg.get();
85
86 // If we don't have a declaration, or we have an invalid declaration,
87 // just return.
88 if (DG.isNull() || !DG.isSingleDecl())
89 return;
90
91 Decl *decl = DG.getSingleDecl();
92 if (!decl || decl->isInvalidDecl())
93 return;
94
95 // Only variable declarations are permitted.
96 VarDecl *var = dyn_cast<VarDecl>(decl);
97 if (!var) {
98 Diag(decl->getLocation(), diag::err_non_variable_decl_in_for);
99 decl->setInvalidDecl();
100 return;
101 }
102
103 // foreach variables are never actually initialized in the way that
104 // the parser came up with.
105 var->setInit(nullptr);
106
107 // In ARC, we don't need to retain the iteration variable of a fast
108 // enumeration loop. Rather than actually trying to catch that
109 // during declaration processing, we remove the consequences here.
110 if (getLangOpts().ObjCAutoRefCount) {
111 QualType type = var->getType();
112
113 // Only do this if we inferred the lifetime. Inferred lifetime
114 // will show up as a local qualifier because explicit lifetime
115 // should have shown up as an AttributedType instead.
116 if (type.getLocalQualifiers().getObjCLifetime() == Qualifiers::OCL_Strong) {
117 // Add 'const' and mark the variable as pseudo-strong.
118 var->setType(type.withConst());
119 var->setARCPseudoStrong(true);
120 }
121 }
122}
123
124/// Diagnose unused comparisons, both builtin and overloaded operators.
125/// For '==' and '!=', suggest fixits for '=' or '|='.
126///
127/// Adding a cast to void (or other expression wrappers) will prevent the
128/// warning from firing.
129static bool DiagnoseUnusedComparison(Sema &S, const Expr *E) {
130 SourceLocation Loc;
131 bool CanAssign;
132 enum { Equality, Inequality, Relational, ThreeWay } Kind;
133
134 if (const BinaryOperator *Op = dyn_cast<BinaryOperator>(E)) {
135 if (!Op->isComparisonOp())
136 return false;
137
138 if (Op->getOpcode() == BO_EQ)
139 Kind = Equality;
140 else if (Op->getOpcode() == BO_NE)
141 Kind = Inequality;
142 else if (Op->getOpcode() == BO_Cmp)
143 Kind = ThreeWay;
144 else {
145 assert(Op->isRelationalOp())(static_cast<void> (0));
146 Kind = Relational;
147 }
148 Loc = Op->getOperatorLoc();
149 CanAssign = Op->getLHS()->IgnoreParenImpCasts()->isLValue();
150 } else if (const CXXOperatorCallExpr *Op = dyn_cast<CXXOperatorCallExpr>(E)) {
151 switch (Op->getOperator()) {
152 case OO_EqualEqual:
153 Kind = Equality;
154 break;
155 case OO_ExclaimEqual:
156 Kind = Inequality;
157 break;
158 case OO_Less:
159 case OO_Greater:
160 case OO_GreaterEqual:
161 case OO_LessEqual:
162 Kind = Relational;
163 break;
164 case OO_Spaceship:
165 Kind = ThreeWay;
166 break;
167 default:
168 return false;
169 }
170
171 Loc = Op->getOperatorLoc();
172 CanAssign = Op->getArg(0)->IgnoreParenImpCasts()->isLValue();
173 } else {
174 // Not a typo-prone comparison.
175 return false;
176 }
177
178 // Suppress warnings when the operator, suspicious as it may be, comes from
179 // a macro expansion.
180 if (S.SourceMgr.isMacroBodyExpansion(Loc))
181 return false;
182
183 S.Diag(Loc, diag::warn_unused_comparison)
184 << (unsigned)Kind << E->getSourceRange();
185
186 // If the LHS is a plausible entity to assign to, provide a fixit hint to
187 // correct common typos.
188 if (CanAssign) {
189 if (Kind == Inequality)
190 S.Diag(Loc, diag::note_inequality_comparison_to_or_assign)
191 << FixItHint::CreateReplacement(Loc, "|=");
192 else if (Kind == Equality)
193 S.Diag(Loc, diag::note_equality_comparison_to_assign)
194 << FixItHint::CreateReplacement(Loc, "=");
195 }
196
197 return true;
198}
199
200static bool DiagnoseNoDiscard(Sema &S, const WarnUnusedResultAttr *A,
201 SourceLocation Loc, SourceRange R1,
202 SourceRange R2, bool IsCtor) {
203 if (!A)
204 return false;
205 StringRef Msg = A->getMessage();
206
207 if (Msg.empty()) {
208 if (IsCtor)
209 return S.Diag(Loc, diag::warn_unused_constructor) << A << R1 << R2;
210 return S.Diag(Loc, diag::warn_unused_result) << A << R1 << R2;
211 }
212
213 if (IsCtor)
214 return S.Diag(Loc, diag::warn_unused_constructor_msg) << A << Msg << R1
215 << R2;
216 return S.Diag(Loc, diag::warn_unused_result_msg) << A << Msg << R1 << R2;
217}
218
219void Sema::DiagnoseUnusedExprResult(const Stmt *S) {
220 if (const LabelStmt *Label = dyn_cast_or_null<LabelStmt>(S))
221 return DiagnoseUnusedExprResult(Label->getSubStmt());
222
223 const Expr *E = dyn_cast_or_null<Expr>(S);
224 if (!E)
225 return;
226
227 // If we are in an unevaluated expression context, then there can be no unused
228 // results because the results aren't expected to be used in the first place.
229 if (isUnevaluatedContext())
230 return;
231
232 SourceLocation ExprLoc = E->IgnoreParenImpCasts()->getExprLoc();
233 // In most cases, we don't want to warn if the expression is written in a
234 // macro body, or if the macro comes from a system header. If the offending
235 // expression is a call to a function with the warn_unused_result attribute,
236 // we warn no matter the location. Because of the order in which the various
237 // checks need to happen, we factor out the macro-related test here.
238 bool ShouldSuppress =
239 SourceMgr.isMacroBodyExpansion(ExprLoc) ||
240 SourceMgr.isInSystemMacro(ExprLoc);
241
242 const Expr *WarnExpr;
243 SourceLocation Loc;
244 SourceRange R1, R2;
245 if (!E->isUnusedResultAWarning(WarnExpr, Loc, R1, R2, Context))
246 return;
247
248 // If this is a GNU statement expression expanded from a macro, it is probably
249 // unused because it is a function-like macro that can be used as either an
250 // expression or statement. Don't warn, because it is almost certainly a
251 // false positive.
252 if (isa<StmtExpr>(E) && Loc.isMacroID())
253 return;
254
255 // Check if this is the UNREFERENCED_PARAMETER from the Microsoft headers.
256 // That macro is frequently used to suppress "unused parameter" warnings,
257 // but its implementation makes clang's -Wunused-value fire. Prevent this.
258 if (isa<ParenExpr>(E->IgnoreImpCasts()) && Loc.isMacroID()) {
259 SourceLocation SpellLoc = Loc;
260 if (findMacroSpelling(SpellLoc, "UNREFERENCED_PARAMETER"))
261 return;
262 }
263
264 // Okay, we have an unused result. Depending on what the base expression is,
265 // we might want to make a more specific diagnostic. Check for one of these
266 // cases now.
267 unsigned DiagID = diag::warn_unused_expr;
268 if (const FullExpr *Temps = dyn_cast<FullExpr>(E))
269 E = Temps->getSubExpr();
270 if (const CXXBindTemporaryExpr *TempExpr = dyn_cast<CXXBindTemporaryExpr>(E))
271 E = TempExpr->getSubExpr();
272
273 if (DiagnoseUnusedComparison(*this, E))
274 return;
275
276 E = WarnExpr;
277 if (const auto *Cast = dyn_cast<CastExpr>(E))
278 if (Cast->getCastKind() == CK_NoOp ||
279 Cast->getCastKind() == CK_ConstructorConversion)
280 E = Cast->getSubExpr()->IgnoreImpCasts();
281
282 if (const CallExpr *CE = dyn_cast<CallExpr>(E)) {
283 if (E->getType()->isVoidType())
284 return;
285
286 if (DiagnoseNoDiscard(*this, cast_or_null<WarnUnusedResultAttr>(
287 CE->getUnusedResultAttr(Context)),
288 Loc, R1, R2, /*isCtor=*/false))
289 return;
290
291 // If the callee has attribute pure, const, or warn_unused_result, warn with
292 // a more specific message to make it clear what is happening. If the call
293 // is written in a macro body, only warn if it has the warn_unused_result
294 // attribute.
295 if (const Decl *FD = CE->getCalleeDecl()) {
296 if (ShouldSuppress)
297 return;
298 if (FD->hasAttr<PureAttr>()) {
299 Diag(Loc, diag::warn_unused_call) << R1 << R2 << "pure";
300 return;
301 }
302 if (FD->hasAttr<ConstAttr>()) {
303 Diag(Loc, diag::warn_unused_call) << R1 << R2 << "const";
304 return;
305 }
306 }
307 } else if (const auto *CE = dyn_cast<CXXConstructExpr>(E)) {
308 if (const CXXConstructorDecl *Ctor = CE->getConstructor()) {
309 const auto *A = Ctor->getAttr<WarnUnusedResultAttr>();
310 A = A ? A : Ctor->getParent()->getAttr<WarnUnusedResultAttr>();
311 if (DiagnoseNoDiscard(*this, A, Loc, R1, R2, /*isCtor=*/true))
312 return;
313 }
314 } else if (const auto *ILE = dyn_cast<InitListExpr>(E)) {
315 if (const TagDecl *TD = ILE->getType()->getAsTagDecl()) {
316
317 if (DiagnoseNoDiscard(*this, TD->getAttr<WarnUnusedResultAttr>(), Loc, R1,
318 R2, /*isCtor=*/false))
319 return;
320 }
321 } else if (ShouldSuppress)
322 return;
323
324 E = WarnExpr;
325 if (const ObjCMessageExpr *ME = dyn_cast<ObjCMessageExpr>(E)) {
326 if (getLangOpts().ObjCAutoRefCount && ME->isDelegateInitCall()) {
327 Diag(Loc, diag::err_arc_unused_init_message) << R1;
328 return;
329 }
330 const ObjCMethodDecl *MD = ME->getMethodDecl();
331 if (MD) {
332 if (DiagnoseNoDiscard(*this, MD->getAttr<WarnUnusedResultAttr>(), Loc, R1,
333 R2, /*isCtor=*/false))
334 return;
335 }
336 } else if (const PseudoObjectExpr *POE = dyn_cast<PseudoObjectExpr>(E)) {
337 const Expr *Source = POE->getSyntacticForm();
338 // Handle the actually selected call of an OpenMP specialized call.
339 if (LangOpts.OpenMP && isa<CallExpr>(Source) &&
340 POE->getNumSemanticExprs() == 1 &&
341 isa<CallExpr>(POE->getSemanticExpr(0)))
342 return DiagnoseUnusedExprResult(POE->getSemanticExpr(0));
343 if (isa<ObjCSubscriptRefExpr>(Source))
344 DiagID = diag::warn_unused_container_subscript_expr;
345 else
346 DiagID = diag::warn_unused_property_expr;
347 } else if (const CXXFunctionalCastExpr *FC
348 = dyn_cast<CXXFunctionalCastExpr>(E)) {
349 const Expr *E = FC->getSubExpr();
350 if (const CXXBindTemporaryExpr *TE = dyn_cast<CXXBindTemporaryExpr>(E))
351 E = TE->getSubExpr();
352 if (isa<CXXTemporaryObjectExpr>(E))
353 return;
354 if (const CXXConstructExpr *CE = dyn_cast<CXXConstructExpr>(E))
355 if (const CXXRecordDecl *RD = CE->getType()->getAsCXXRecordDecl())
356 if (!RD->getAttr<WarnUnusedAttr>())
357 return;
358 }
359 // Diagnose "(void*) blah" as a typo for "(void) blah".
360 else if (const CStyleCastExpr *CE = dyn_cast<CStyleCastExpr>(E)) {
361 TypeSourceInfo *TI = CE->getTypeInfoAsWritten();
362 QualType T = TI->getType();
363
364 // We really do want to use the non-canonical type here.
365 if (T == Context.VoidPtrTy) {
366 PointerTypeLoc TL = TI->getTypeLoc().castAs<PointerTypeLoc>();
367
368 Diag(Loc, diag::warn_unused_voidptr)
369 << FixItHint::CreateRemoval(TL.getStarLoc());
370 return;
371 }
372 }
373
374 // Tell the user to assign it into a variable to force a volatile load if this
375 // isn't an array.
376 if (E->isGLValue() && E->getType().isVolatileQualified() &&
377 !E->getType()->isArrayType()) {
378 Diag(Loc, diag::warn_unused_volatile) << R1 << R2;
379 return;
380 }
381
382 DiagRuntimeBehavior(Loc, nullptr, PDiag(DiagID) << R1 << R2);
383}
384
385void Sema::ActOnStartOfCompoundStmt(bool IsStmtExpr) {
386 PushCompoundScope(IsStmtExpr);
387}
388
389void Sema::ActOnAfterCompoundStatementLeadingPragmas() {
390 if (getCurFPFeatures().isFPConstrained()) {
391 FunctionScopeInfo *FSI = getCurFunction();
392 assert(FSI)(static_cast<void> (0));
393 FSI->setUsesFPIntrin();
394 }
395}
396
397void Sema::ActOnFinishOfCompoundStmt() {
398 PopCompoundScope();
399}
400
401sema::CompoundScopeInfo &Sema::getCurCompoundScope() const {
402 return getCurFunction()->CompoundScopes.back();
403}
404
405StmtResult Sema::ActOnCompoundStmt(SourceLocation L, SourceLocation R,
406 ArrayRef<Stmt *> Elts, bool isStmtExpr) {
407 const unsigned NumElts = Elts.size();
408
409 // If we're in C89 mode, check that we don't have any decls after stmts. If
410 // so, emit an extension diagnostic.
411 if (!getLangOpts().C99 && !getLangOpts().CPlusPlus) {
412 // Note that __extension__ can be around a decl.
413 unsigned i = 0;
414 // Skip over all declarations.
415 for (; i != NumElts && isa<DeclStmt>(Elts[i]); ++i)
416 /*empty*/;
417
418 // We found the end of the list or a statement. Scan for another declstmt.
419 for (; i != NumElts && !isa<DeclStmt>(Elts[i]); ++i)
420 /*empty*/;
421
422 if (i != NumElts) {
423 Decl *D = *cast<DeclStmt>(Elts[i])->decl_begin();
424 Diag(D->getLocation(), diag::ext_mixed_decls_code);
425 }
426 }
427
428 // Check for suspicious empty body (null statement) in `for' and `while'
429 // statements. Don't do anything for template instantiations, this just adds
430 // noise.
431 if (NumElts != 0 && !CurrentInstantiationScope &&
432 getCurCompoundScope().HasEmptyLoopBodies) {
433 for (unsigned i = 0; i != NumElts - 1; ++i)
434 DiagnoseEmptyLoopBody(Elts[i], Elts[i + 1]);
435 }
436
437 return CompoundStmt::Create(Context, Elts, L, R);
438}
439
440ExprResult
441Sema::ActOnCaseExpr(SourceLocation CaseLoc, ExprResult Val) {
442 if (!Val.get())
443 return Val;
444
445 if (DiagnoseUnexpandedParameterPack(Val.get()))
446 return ExprError();
447
448 // If we're not inside a switch, let the 'case' statement handling diagnose
449 // this. Just clean up after the expression as best we can.
450 if (getCurFunction()->SwitchStack.empty())
451 return ActOnFinishFullExpr(Val.get(), Val.get()->getExprLoc(), false,
452 getLangOpts().CPlusPlus11);
453
454 Expr *CondExpr =
455 getCurFunction()->SwitchStack.back().getPointer()->getCond();
456 if (!CondExpr)
457 return ExprError();
458 QualType CondType = CondExpr->getType();
459
460 auto CheckAndFinish = [&](Expr *E) {
461 if (CondType->isDependentType() || E->isTypeDependent())
462 return ExprResult(E);
463
464 if (getLangOpts().CPlusPlus11) {
465 // C++11 [stmt.switch]p2: the constant-expression shall be a converted
466 // constant expression of the promoted type of the switch condition.
467 llvm::APSInt TempVal;
468 return CheckConvertedConstantExpression(E, CondType, TempVal,
469 CCEK_CaseValue);
470 }
471
472 ExprResult ER = E;
473 if (!E->isValueDependent())
474 ER = VerifyIntegerConstantExpression(E, AllowFold);
475 if (!ER.isInvalid())
476 ER = DefaultLvalueConversion(ER.get());
477 if (!ER.isInvalid())
478 ER = ImpCastExprToType(ER.get(), CondType, CK_IntegralCast);
479 if (!ER.isInvalid())
480 ER = ActOnFinishFullExpr(ER.get(), ER.get()->getExprLoc(), false);
481 return ER;
482 };
483
484 ExprResult Converted = CorrectDelayedTyposInExpr(
485 Val, /*InitDecl=*/nullptr, /*RecoverUncorrectedTypos=*/false,
486 CheckAndFinish);
487 if (Converted.get() == Val.get())
488 Converted = CheckAndFinish(Val.get());
489 return Converted;
490}
491
492StmtResult
493Sema::ActOnCaseStmt(SourceLocation CaseLoc, ExprResult LHSVal,
494 SourceLocation DotDotDotLoc, ExprResult RHSVal,
495 SourceLocation ColonLoc) {
496 assert((LHSVal.isInvalid() || LHSVal.get()) && "missing LHS value")(static_cast<void> (0));
497 assert((DotDotDotLoc.isInvalid() ? RHSVal.isUnset()(static_cast<void> (0))
498 : RHSVal.isInvalid() || RHSVal.get()) &&(static_cast<void> (0))
499 "missing RHS value")(static_cast<void> (0));
500
501 if (getCurFunction()->SwitchStack.empty()) {
502 Diag(CaseLoc, diag::err_case_not_in_switch);
503 return StmtError();
504 }
505
506 if (LHSVal.isInvalid() || RHSVal.isInvalid()) {
507 getCurFunction()->SwitchStack.back().setInt(true);
508 return StmtError();
509 }
510
511 auto *CS = CaseStmt::Create(Context, LHSVal.get(), RHSVal.get(),
512 CaseLoc, DotDotDotLoc, ColonLoc);
513 getCurFunction()->SwitchStack.back().getPointer()->addSwitchCase(CS);
514 return CS;
515}
516
517/// ActOnCaseStmtBody - This installs a statement as the body of a case.
518void Sema::ActOnCaseStmtBody(Stmt *S, Stmt *SubStmt) {
519 cast<CaseStmt>(S)->setSubStmt(SubStmt);
520}
521
522StmtResult
523Sema::ActOnDefaultStmt(SourceLocation DefaultLoc, SourceLocation ColonLoc,
524 Stmt *SubStmt, Scope *CurScope) {
525 if (getCurFunction()->SwitchStack.empty()) {
526 Diag(DefaultLoc, diag::err_default_not_in_switch);
527 return SubStmt;
528 }
529
530 DefaultStmt *DS = new (Context) DefaultStmt(DefaultLoc, ColonLoc, SubStmt);
531 getCurFunction()->SwitchStack.back().getPointer()->addSwitchCase(DS);
532 return DS;
533}
534
535StmtResult
536Sema::ActOnLabelStmt(SourceLocation IdentLoc, LabelDecl *TheDecl,
537 SourceLocation ColonLoc, Stmt *SubStmt) {
538 // If the label was multiply defined, reject it now.
539 if (TheDecl->getStmt()) {
540 Diag(IdentLoc, diag::err_redefinition_of_label) << TheDecl->getDeclName();
541 Diag(TheDecl->getLocation(), diag::note_previous_definition);
542 return SubStmt;
543 }
544
545 ReservedIdentifierStatus Status = TheDecl->isReserved(getLangOpts());
546 if (Status != ReservedIdentifierStatus::NotReserved &&
547 !Context.getSourceManager().isInSystemHeader(IdentLoc))
548 Diag(IdentLoc, diag::warn_reserved_extern_symbol)
549 << TheDecl << static_cast<int>(Status);
550
551 // Otherwise, things are good. Fill in the declaration and return it.
552 LabelStmt *LS = new (Context) LabelStmt(IdentLoc, TheDecl, SubStmt);
553 TheDecl->setStmt(LS);
554 if (!TheDecl->isGnuLocal()) {
555 TheDecl->setLocStart(IdentLoc);
556 if (!TheDecl->isMSAsmLabel()) {
557 // Don't update the location of MS ASM labels. These will result in
558 // a diagnostic, and changing the location here will mess that up.
559 TheDecl->setLocation(IdentLoc);
560 }
561 }
562 return LS;
563}
564
565StmtResult Sema::BuildAttributedStmt(SourceLocation AttrsLoc,
566 ArrayRef<const Attr *> Attrs,
567 Stmt *SubStmt) {
568 // FIXME: this code should move when a planned refactoring around statement
569 // attributes lands.
570 for (const auto *A : Attrs) {
571 if (A->getKind() == attr::MustTail) {
572 if (!checkAndRewriteMustTailAttr(SubStmt, *A)) {
573 return SubStmt;
574 }
575 setFunctionHasMustTail();
576 }
577 }
578
579 return AttributedStmt::Create(Context, AttrsLoc, Attrs, SubStmt);
580}
581
582StmtResult Sema::ActOnAttributedStmt(const ParsedAttributesWithRange &Attrs,
583 Stmt *SubStmt) {
584 SmallVector<const Attr *, 1> SemanticAttrs;
585 ProcessStmtAttributes(SubStmt, Attrs, SemanticAttrs);
586 if (!SemanticAttrs.empty())
587 return BuildAttributedStmt(Attrs.Range.getBegin(), SemanticAttrs, SubStmt);
588 // If none of the attributes applied, that's fine, we can recover by
589 // returning the substatement directly instead of making an AttributedStmt
590 // with no attributes on it.
591 return SubStmt;
592}
593
594bool Sema::checkAndRewriteMustTailAttr(Stmt *St, const Attr &MTA) {
595 ReturnStmt *R = cast<ReturnStmt>(St);
596 Expr *E = R->getRetValue();
597
598 if (CurContext->isDependentContext() || (E && E->isInstantiationDependent()))
599 // We have to suspend our check until template instantiation time.
600 return true;
601
602 if (!checkMustTailAttr(St, MTA))
603 return false;
604
605 // FIXME: Replace Expr::IgnoreImplicitAsWritten() with this function.
606 // Currently it does not skip implicit constructors in an initialization
607 // context.
608 auto IgnoreImplicitAsWritten = [](Expr *E) -> Expr * {
609 return IgnoreExprNodes(E, IgnoreImplicitAsWrittenSingleStep,
610 IgnoreElidableImplicitConstructorSingleStep);
611 };
612
613 // Now that we have verified that 'musttail' is valid here, rewrite the
614 // return value to remove all implicit nodes, but retain parentheses.
615 R->setRetValue(IgnoreImplicitAsWritten(E));
616 return true;
617}
618
619bool Sema::checkMustTailAttr(const Stmt *St, const Attr &MTA) {
620 assert(!CurContext->isDependentContext() &&(static_cast<void> (0))
621 "musttail cannot be checked from a dependent context")(static_cast<void> (0));
622
623 // FIXME: Add Expr::IgnoreParenImplicitAsWritten() with this definition.
624 auto IgnoreParenImplicitAsWritten = [](const Expr *E) -> const Expr * {
625 return IgnoreExprNodes(const_cast<Expr *>(E), IgnoreParensSingleStep,
626 IgnoreImplicitAsWrittenSingleStep,
627 IgnoreElidableImplicitConstructorSingleStep);
628 };
629
630 const Expr *E = cast<ReturnStmt>(St)->getRetValue();
631 const auto *CE = dyn_cast_or_null<CallExpr>(IgnoreParenImplicitAsWritten(E));
632
633 if (!CE) {
634 Diag(St->getBeginLoc(), diag::err_musttail_needs_call) << &MTA;
635 return false;
636 }
637
638 if (const auto *EWC = dyn_cast<ExprWithCleanups>(E)) {
639 if (EWC->cleanupsHaveSideEffects()) {
640 Diag(St->getBeginLoc(), diag::err_musttail_needs_trivial_args) << &MTA;
641 return false;
642 }
643 }
644
645 // We need to determine the full function type (including "this" type, if any)
646 // for both caller and callee.
647 struct FuncType {
648 enum {
649 ft_non_member,
650 ft_static_member,
651 ft_non_static_member,
652 ft_pointer_to_member,
653 } MemberType = ft_non_member;
654
655 QualType This;
656 const FunctionProtoType *Func;
657 const CXXMethodDecl *Method = nullptr;
658 } CallerType, CalleeType;
659
660 auto GetMethodType = [this, St, MTA](const CXXMethodDecl *CMD, FuncType &Type,
661 bool IsCallee) -> bool {
662 if (isa<CXXConstructorDecl, CXXDestructorDecl>(CMD)) {
663 Diag(St->getBeginLoc(), diag::err_musttail_structors_forbidden)
664 << IsCallee << isa<CXXDestructorDecl>(CMD);
665 if (IsCallee)
666 Diag(CMD->getBeginLoc(), diag::note_musttail_structors_forbidden)
667 << isa<CXXDestructorDecl>(CMD);
668 Diag(MTA.getLocation(), diag::note_tail_call_required) << &MTA;
669 return false;
670 }
671 if (CMD->isStatic())
672 Type.MemberType = FuncType::ft_static_member;
673 else {
674 Type.This = CMD->getThisType()->getPointeeType();
675 Type.MemberType = FuncType::ft_non_static_member;
676 }
677 Type.Func = CMD->getType()->castAs<FunctionProtoType>();
678 return true;
679 };
680
681 const auto *CallerDecl = dyn_cast<FunctionDecl>(CurContext);
682
683 // Find caller function signature.
684 if (!CallerDecl) {
685 int ContextType;
686 if (isa<BlockDecl>(CurContext))
687 ContextType = 0;
688 else if (isa<ObjCMethodDecl>(CurContext))
689 ContextType = 1;
690 else
691 ContextType = 2;
692 Diag(St->getBeginLoc(), diag::err_musttail_forbidden_from_this_context)
693 << &MTA << ContextType;
694 return false;
695 } else if (const auto *CMD = dyn_cast<CXXMethodDecl>(CurContext)) {
696 // Caller is a class/struct method.
697 if (!GetMethodType(CMD, CallerType, false))
698 return false;
699 } else {
700 // Caller is a non-method function.
701 CallerType.Func = CallerDecl->getType()->getAs<FunctionProtoType>();
702 }
703
704 const Expr *CalleeExpr = CE->getCallee()->IgnoreParens();
705 const auto *CalleeBinOp = dyn_cast<BinaryOperator>(CalleeExpr);
706 SourceLocation CalleeLoc = CE->getCalleeDecl()
707 ? CE->getCalleeDecl()->getBeginLoc()
708 : St->getBeginLoc();
709
710 // Find callee function signature.
711 if (const CXXMethodDecl *CMD =
712 dyn_cast_or_null<CXXMethodDecl>(CE->getCalleeDecl())) {
713 // Call is: obj.method(), obj->method(), functor(), etc.
714 if (!GetMethodType(CMD, CalleeType, true))
715 return false;
716 } else if (CalleeBinOp && CalleeBinOp->isPtrMemOp()) {
717 // Call is: obj->*method_ptr or obj.*method_ptr
718 const auto *MPT =
719 CalleeBinOp->getRHS()->getType()->castAs<MemberPointerType>();
720 CalleeType.This = QualType(MPT->getClass(), 0);
721 CalleeType.Func = MPT->getPointeeType()->castAs<FunctionProtoType>();
722 CalleeType.MemberType = FuncType::ft_pointer_to_member;
723 } else if (isa<CXXPseudoDestructorExpr>(CalleeExpr)) {
724 Diag(St->getBeginLoc(), diag::err_musttail_structors_forbidden)
725 << /* IsCallee = */ 1 << /* IsDestructor = */ 1;
726 Diag(MTA.getLocation(), diag::note_tail_call_required) << &MTA;
727 return false;
728 } else {
729 // Non-method function.
730 CalleeType.Func =
731 CalleeExpr->getType()->getPointeeType()->getAs<FunctionProtoType>();
732 }
733
734 // Both caller and callee must have a prototype (no K&R declarations).
735 if (!CalleeType.Func || !CallerType.Func) {
736 Diag(St->getBeginLoc(), diag::err_musttail_needs_prototype) << &MTA;
737 if (!CalleeType.Func && CE->getDirectCallee()) {
738 Diag(CE->getDirectCallee()->getBeginLoc(),
739 diag::note_musttail_fix_non_prototype);
740 }
741 if (!CallerType.Func)
742 Diag(CallerDecl->getBeginLoc(), diag::note_musttail_fix_non_prototype);
743 return false;
744 }
745
746 // Caller and callee must have matching calling conventions.
747 //
748 // Some calling conventions are physically capable of supporting tail calls
749 // even if the function types don't perfectly match. LLVM is currently too
750 // strict to allow this, but if LLVM added support for this in the future, we
751 // could exit early here and skip the remaining checks if the functions are
752 // using such a calling convention.
753 if (CallerType.Func->getCallConv() != CalleeType.Func->getCallConv()) {
754 if (const auto *ND = dyn_cast_or_null<NamedDecl>(CE->getCalleeDecl()))
755 Diag(St->getBeginLoc(), diag::err_musttail_callconv_mismatch)
756 << true << ND->getDeclName();
757 else
758 Diag(St->getBeginLoc(), diag::err_musttail_callconv_mismatch) << false;
759 Diag(CalleeLoc, diag::note_musttail_callconv_mismatch)
760 << FunctionType::getNameForCallConv(CallerType.Func->getCallConv())
761 << FunctionType::getNameForCallConv(CalleeType.Func->getCallConv());
762 Diag(MTA.getLocation(), diag::note_tail_call_required) << &MTA;
763 return false;
764 }
765
766 if (CalleeType.Func->isVariadic() || CallerType.Func->isVariadic()) {
767 Diag(St->getBeginLoc(), diag::err_musttail_no_variadic) << &MTA;
768 return false;
769 }
770
771 // Caller and callee must match in whether they have a "this" parameter.
772 if (CallerType.This.isNull() != CalleeType.This.isNull()) {
773 if (const auto *ND = dyn_cast_or_null<NamedDecl>(CE->getCalleeDecl())) {
774 Diag(St->getBeginLoc(), diag::err_musttail_member_mismatch)
775 << CallerType.MemberType << CalleeType.MemberType << true
776 << ND->getDeclName();
777 Diag(CalleeLoc, diag::note_musttail_callee_defined_here)
778 << ND->getDeclName();
779 } else
780 Diag(St->getBeginLoc(), diag::err_musttail_member_mismatch)
781 << CallerType.MemberType << CalleeType.MemberType << false;
782 Diag(MTA.getLocation(), diag::note_tail_call_required) << &MTA;
783 return false;
784 }
785
786 auto CheckTypesMatch = [this](FuncType CallerType, FuncType CalleeType,
787 PartialDiagnostic &PD) -> bool {
788 enum {
789 ft_different_class,
790 ft_parameter_arity,
791 ft_parameter_mismatch,
792 ft_return_type,
793 };
794
795 auto DoTypesMatch = [this, &PD](QualType A, QualType B,
796 unsigned Select) -> bool {
797 if (!Context.hasSimilarType(A, B)) {
798 PD << Select << A.getUnqualifiedType() << B.getUnqualifiedType();
799 return false;
800 }
801 return true;
802 };
803
804 if (!CallerType.This.isNull() &&
805 !DoTypesMatch(CallerType.This, CalleeType.This, ft_different_class))
806 return false;
807
808 if (!DoTypesMatch(CallerType.Func->getReturnType(),
809 CalleeType.Func->getReturnType(), ft_return_type))
810 return false;
811
812 if (CallerType.Func->getNumParams() != CalleeType.Func->getNumParams()) {
813 PD << ft_parameter_arity << CallerType.Func->getNumParams()
814 << CalleeType.Func->getNumParams();
815 return false;
816 }
817
818 ArrayRef<QualType> CalleeParams = CalleeType.Func->getParamTypes();
819 ArrayRef<QualType> CallerParams = CallerType.Func->getParamTypes();
820 size_t N = CallerType.Func->getNumParams();
821 for (size_t I = 0; I < N; I++) {
822 if (!DoTypesMatch(CalleeParams[I], CallerParams[I],
823 ft_parameter_mismatch)) {
824 PD << static_cast<int>(I) + 1;
825 return false;
826 }
827 }
828
829 return true;
830 };
831
832 PartialDiagnostic PD = PDiag(diag::note_musttail_mismatch);
833 if (!CheckTypesMatch(CallerType, CalleeType, PD)) {
834 if (const auto *ND = dyn_cast_or_null<NamedDecl>(CE->getCalleeDecl()))
835 Diag(St->getBeginLoc(), diag::err_musttail_mismatch)
836 << true << ND->getDeclName();
837 else
838 Diag(St->getBeginLoc(), diag::err_musttail_mismatch) << false;
839 Diag(CalleeLoc, PD);
840 Diag(MTA.getLocation(), diag::note_tail_call_required) << &MTA;
841 return false;
842 }
843
844 return true;
845}
846
847namespace {
848class CommaVisitor : public EvaluatedExprVisitor<CommaVisitor> {
849 typedef EvaluatedExprVisitor<CommaVisitor> Inherited;
850 Sema &SemaRef;
851public:
852 CommaVisitor(Sema &SemaRef) : Inherited(SemaRef.Context), SemaRef(SemaRef) {}
853 void VisitBinaryOperator(BinaryOperator *E) {
854 if (E->getOpcode() == BO_Comma)
855 SemaRef.DiagnoseCommaOperator(E->getLHS(), E->getExprLoc());
856 EvaluatedExprVisitor<CommaVisitor>::VisitBinaryOperator(E);
857 }
858};
859}
860
861StmtResult Sema::ActOnIfStmt(SourceLocation IfLoc, bool IsConstexpr,
862 SourceLocation LParenLoc, Stmt *InitStmt,
863 ConditionResult Cond, SourceLocation RParenLoc,
864 Stmt *thenStmt, SourceLocation ElseLoc,
865 Stmt *elseStmt) {
866 if (Cond.isInvalid())
867 Cond = ConditionResult(
868 *this, nullptr,
869 MakeFullExpr(new (Context) OpaqueValueExpr(SourceLocation(),
870 Context.BoolTy, VK_PRValue),
871 IfLoc),
872 false);
873
874 Expr *CondExpr = Cond.get().second;
875 // Only call the CommaVisitor when not C89 due to differences in scope flags.
876 if ((getLangOpts().C99 || getLangOpts().CPlusPlus) &&
877 !Diags.isIgnored(diag::warn_comma_operator, CondExpr->getExprLoc()))
878 CommaVisitor(*this).Visit(CondExpr);
879
880 if (!elseStmt)
881 DiagnoseEmptyStmtBody(CondExpr->getEndLoc(), thenStmt,
882 diag::warn_empty_if_body);
883
884 if (IsConstexpr) {
885 auto DiagnoseLikelihood = [&](const Stmt *S) {
886 if (const Attr *A = Stmt::getLikelihoodAttr(S)) {
887 Diags.Report(A->getLocation(),
888 diag::warn_attribute_has_no_effect_on_if_constexpr)
889 << A << A->getRange();
890 Diags.Report(IfLoc,
891 diag::note_attribute_has_no_effect_on_if_constexpr_here)
892 << SourceRange(IfLoc, LParenLoc.getLocWithOffset(-1));
893 }
894 };
895 DiagnoseLikelihood(thenStmt);
896 DiagnoseLikelihood(elseStmt);
897 } else {
898 std::tuple<bool, const Attr *, const Attr *> LHC =
899 Stmt::determineLikelihoodConflict(thenStmt, elseStmt);
900 if (std::get<0>(LHC)) {
901 const Attr *ThenAttr = std::get<1>(LHC);
902 const Attr *ElseAttr = std::get<2>(LHC);
903 Diags.Report(ThenAttr->getLocation(),
904 diag::warn_attributes_likelihood_ifstmt_conflict)
905 << ThenAttr << ThenAttr->getRange();
906 Diags.Report(ElseAttr->getLocation(), diag::note_conflicting_attribute)
907 << ElseAttr << ElseAttr->getRange();
908 }
909 }
910
911 return BuildIfStmt(IfLoc, IsConstexpr, LParenLoc, InitStmt, Cond, RParenLoc,
912 thenStmt, ElseLoc, elseStmt);
913}
914
915StmtResult Sema::BuildIfStmt(SourceLocation IfLoc, bool IsConstexpr,
916 SourceLocation LParenLoc, Stmt *InitStmt,
917 ConditionResult Cond, SourceLocation RParenLoc,
918 Stmt *thenStmt, SourceLocation ElseLoc,
919 Stmt *elseStmt) {
920 if (Cond.isInvalid())
921 return StmtError();
922
923 if (IsConstexpr || isa<ObjCAvailabilityCheckExpr>(Cond.get().second))
924 setFunctionHasBranchProtectedScope();
925
926 return IfStmt::Create(Context, IfLoc, IsConstexpr, InitStmt, Cond.get().first,
927 Cond.get().second, LParenLoc, RParenLoc, thenStmt,
928 ElseLoc, elseStmt);
929}
930
931namespace {
932 struct CaseCompareFunctor {
933 bool operator()(const std::pair<llvm::APSInt, CaseStmt*> &LHS,
934 const llvm::APSInt &RHS) {
935 return LHS.first < RHS;
936 }
937 bool operator()(const std::pair<llvm::APSInt, CaseStmt*> &LHS,
938 const std::pair<llvm::APSInt, CaseStmt*> &RHS) {
939 return LHS.first < RHS.first;
940 }
941 bool operator()(const llvm::APSInt &LHS,
942 const std::pair<llvm::APSInt, CaseStmt*> &RHS) {
943 return LHS < RHS.first;
944 }
945 };
946}
947
948/// CmpCaseVals - Comparison predicate for sorting case values.
949///
950static bool CmpCaseVals(const std::pair<llvm::APSInt, CaseStmt*>& lhs,
951 const std::pair<llvm::APSInt, CaseStmt*>& rhs) {
952 if (lhs.first < rhs.first)
953 return true;
954
955 if (lhs.first == rhs.first &&
956 lhs.second->getCaseLoc() < rhs.second->getCaseLoc())
957 return true;
958 return false;
959}
960
961/// CmpEnumVals - Comparison predicate for sorting enumeration values.
962///
963static bool CmpEnumVals(const std::pair<llvm::APSInt, EnumConstantDecl*>& lhs,
964 const std::pair<llvm::APSInt, EnumConstantDecl*>& rhs)
965{
966 return lhs.first < rhs.first;
967}
968
969/// EqEnumVals - Comparison preficate for uniqing enumeration values.
970///
971static bool EqEnumVals(const std::pair<llvm::APSInt, EnumConstantDecl*>& lhs,
972 const std::pair<llvm::APSInt, EnumConstantDecl*>& rhs)
973{
974 return lhs.first == rhs.first;
975}
976
977/// GetTypeBeforeIntegralPromotion - Returns the pre-promotion type of
978/// potentially integral-promoted expression @p expr.
979static QualType GetTypeBeforeIntegralPromotion(const Expr *&E) {
980 if (const auto *FE = dyn_cast<FullExpr>(E))
981 E = FE->getSubExpr();
982 while (const auto *ImpCast = dyn_cast<ImplicitCastExpr>(E)) {
983 if (ImpCast->getCastKind() != CK_IntegralCast) break;
984 E = ImpCast->getSubExpr();
985 }
986 return E->getType();
987}
988
989ExprResult Sema::CheckSwitchCondition(SourceLocation SwitchLoc, Expr *Cond) {
990 class SwitchConvertDiagnoser : public ICEConvertDiagnoser {
991 Expr *Cond;
992
993 public:
994 SwitchConvertDiagnoser(Expr *Cond)
995 : ICEConvertDiagnoser(/*AllowScopedEnumerations*/true, false, true),
996 Cond(Cond) {}
997
998 SemaDiagnosticBuilder diagnoseNotInt(Sema &S, SourceLocation Loc,
999 QualType T) override {
1000 return S.Diag(Loc, diag::err_typecheck_statement_requires_integer) << T;
1001 }
1002
1003 SemaDiagnosticBuilder diagnoseIncomplete(
1004 Sema &S, SourceLocation Loc, QualType T) override {
1005 return S.Diag(Loc, diag::err_switch_incomplete_class_type)
1006 << T << Cond->getSourceRange();
1007 }
1008
1009 SemaDiagnosticBuilder diagnoseExplicitConv(
1010 Sema &S, SourceLocation Loc, QualType T, QualType ConvTy) override {
1011 return S.Diag(Loc, diag::err_switch_explicit_conversion) << T << ConvTy;
1012 }
1013
1014 SemaDiagnosticBuilder noteExplicitConv(
1015 Sema &S, CXXConversionDecl *Conv, QualType ConvTy) override {
1016 return S.Diag(Conv->getLocation(), diag::note_switch_conversion)
1017 << ConvTy->isEnumeralType() << ConvTy;
1018 }
1019
1020 SemaDiagnosticBuilder diagnoseAmbiguous(Sema &S, SourceLocation Loc,
1021 QualType T) override {
1022 return S.Diag(Loc, diag::err_switch_multiple_conversions) << T;
1023 }
1024
1025 SemaDiagnosticBuilder noteAmbiguous(
1026 Sema &S, CXXConversionDecl *Conv, QualType ConvTy) override {
1027 return S.Diag(Conv->getLocation(), diag::note_switch_conversion)
1028 << ConvTy->isEnumeralType() << ConvTy;
1029 }
1030
1031 SemaDiagnosticBuilder diagnoseConversion(
1032 Sema &S, SourceLocation Loc, QualType T, QualType ConvTy) override {
1033 llvm_unreachable("conversion functions are permitted")__builtin_unreachable();
1034 }
1035 } SwitchDiagnoser(Cond);
1036
1037 ExprResult CondResult =
1038 PerformContextualImplicitConversion(SwitchLoc, Cond, SwitchDiagnoser);
1039 if (CondResult.isInvalid())
1040 return ExprError();
1041
1042 // FIXME: PerformContextualImplicitConversion doesn't always tell us if it
1043 // failed and produced a diagnostic.
1044 Cond = CondResult.get();
1045 if (!Cond->isTypeDependent() &&
1046 !Cond->getType()->isIntegralOrEnumerationType())
1047 return ExprError();
1048
1049 // C99 6.8.4.2p5 - Integer promotions are performed on the controlling expr.
1050 return UsualUnaryConversions(Cond);
1051}
1052
1053StmtResult Sema::ActOnStartOfSwitchStmt(SourceLocation SwitchLoc,
1054 SourceLocation LParenLoc,
1055 Stmt *InitStmt, ConditionResult Cond,
1056 SourceLocation RParenLoc) {
1057 Expr *CondExpr = Cond.get().second;
1058 assert((Cond.isInvalid() || CondExpr) && "switch with no condition")(static_cast<void> (0));
1059
1060 if (CondExpr && !CondExpr->isTypeDependent()) {
1061 // We have already converted the expression to an integral or enumeration
1062 // type, when we parsed the switch condition. There are cases where we don't
1063 // have an appropriate type, e.g. a typo-expr Cond was corrected to an
1064 // inappropriate-type expr, we just return an error.
1065 if (!CondExpr->getType()->isIntegralOrEnumerationType())
1066 return StmtError();
1067 if (CondExpr->isKnownToHaveBooleanValue()) {
1068 // switch(bool_expr) {...} is often a programmer error, e.g.
1069 // switch(n && mask) { ... } // Doh - should be "n & mask".
1070 // One can always use an if statement instead of switch(bool_expr).
1071 Diag(SwitchLoc, diag::warn_bool_switch_condition)
1072 << CondExpr->getSourceRange();
1073 }
1074 }
1075
1076 setFunctionHasBranchIntoScope();
1077
1078 auto *SS = SwitchStmt::Create(Context, InitStmt, Cond.get().first, CondExpr,
1079 LParenLoc, RParenLoc);
1080 getCurFunction()->SwitchStack.push_back(
1081 FunctionScopeInfo::SwitchInfo(SS, false));
1082 return SS;
1083}
1084
1085static void AdjustAPSInt(llvm::APSInt &Val, unsigned BitWidth, bool IsSigned) {
1086 Val = Val.extOrTrunc(BitWidth);
1087 Val.setIsSigned(IsSigned);
1088}
1089
1090/// Check the specified case value is in range for the given unpromoted switch
1091/// type.
1092static void checkCaseValue(Sema &S, SourceLocation Loc, const llvm::APSInt &Val,
1093 unsigned UnpromotedWidth, bool UnpromotedSign) {
1094 // In C++11 onwards, this is checked by the language rules.
1095 if (S.getLangOpts().CPlusPlus11)
1096 return;
1097
1098 // If the case value was signed and negative and the switch expression is
1099 // unsigned, don't bother to warn: this is implementation-defined behavior.
1100 // FIXME: Introduce a second, default-ignored warning for this case?
1101 if (UnpromotedWidth < Val.getBitWidth()) {
1102 llvm::APSInt ConvVal(Val);
1103 AdjustAPSInt(ConvVal, UnpromotedWidth, UnpromotedSign);
1104 AdjustAPSInt(ConvVal, Val.getBitWidth(), Val.isSigned());
1105 // FIXME: Use different diagnostics for overflow in conversion to promoted
1106 // type versus "switch expression cannot have this value". Use proper
1107 // IntRange checking rather than just looking at the unpromoted type here.
1108 if (ConvVal != Val)
1109 S.Diag(Loc, diag::warn_case_value_overflow) << toString(Val, 10)
1110 << toString(ConvVal, 10);
1111 }
1112}
1113
1114typedef SmallVector<std::pair<llvm::APSInt, EnumConstantDecl*>, 64> EnumValsTy;
1115
1116/// Returns true if we should emit a diagnostic about this case expression not
1117/// being a part of the enum used in the switch controlling expression.
1118static bool ShouldDiagnoseSwitchCaseNotInEnum(const Sema &S,
1119 const EnumDecl *ED,
1120 const Expr *CaseExpr,
1121 EnumValsTy::iterator &EI,
1122 EnumValsTy::iterator &EIEnd,
1123 const llvm::APSInt &Val) {
1124 if (!ED->isClosed())
1125 return false;
1126
1127 if (const DeclRefExpr *DRE =
1128 dyn_cast<DeclRefExpr>(CaseExpr->IgnoreParenImpCasts())) {
1129 if (const VarDecl *VD = dyn_cast<VarDecl>(DRE->getDecl())) {
1130 QualType VarType = VD->getType();
1131 QualType EnumType = S.Context.getTypeDeclType(ED);
1132 if (VD->hasGlobalStorage() && VarType.isConstQualified() &&
1133 S.Context.hasSameUnqualifiedType(EnumType, VarType))
1134 return false;
1135 }
1136 }
1137
1138 if (ED->hasAttr<FlagEnumAttr>())
1139 return !S.IsValueInFlagEnum(ED, Val, false);
1140
1141 while (EI != EIEnd && EI->first < Val)
1142 EI++;
1143
1144 if (EI != EIEnd && EI->first == Val)
1145 return false;
1146
1147 return true;
1148}
1149
1150static void checkEnumTypesInSwitchStmt(Sema &S, const Expr *Cond,
1151 const Expr *Case) {
1152 QualType CondType = Cond->getType();
1153 QualType CaseType = Case->getType();
1154
1155 const EnumType *CondEnumType = CondType->getAs<EnumType>();
1156 const EnumType *CaseEnumType = CaseType->getAs<EnumType>();
1157 if (!CondEnumType || !CaseEnumType)
1158 return;
1159
1160 // Ignore anonymous enums.
1161 if (!CondEnumType->getDecl()->getIdentifier() &&
1162 !CondEnumType->getDecl()->getTypedefNameForAnonDecl())
1163 return;
1164 if (!CaseEnumType->getDecl()->getIdentifier() &&
1165 !CaseEnumType->getDecl()->getTypedefNameForAnonDecl())
1166 return;
1167
1168 if (S.Context.hasSameUnqualifiedType(CondType, CaseType))
1169 return;
1170
1171 S.Diag(Case->getExprLoc(), diag::warn_comparison_of_mixed_enum_types_switch)
1172 << CondType << CaseType << Cond->getSourceRange()
1173 << Case->getSourceRange();
1174}
1175
1176StmtResult
1177Sema::ActOnFinishSwitchStmt(SourceLocation SwitchLoc, Stmt *Switch,
1178 Stmt *BodyStmt) {
1179 SwitchStmt *SS = cast<SwitchStmt>(Switch);
1180 bool CaseListIsIncomplete = getCurFunction()->SwitchStack.back().getInt();
1181 assert(SS == getCurFunction()->SwitchStack.back().getPointer() &&(static_cast<void> (0))
1182 "switch stack missing push/pop!")(static_cast<void> (0));
1183
1184 getCurFunction()->SwitchStack.pop_back();
1185
1186 if (!BodyStmt) return StmtError();
1187 SS->setBody(BodyStmt, SwitchLoc);
1188
1189 Expr *CondExpr = SS->getCond();
1190 if (!CondExpr) return StmtError();
1191
1192 QualType CondType = CondExpr->getType();
1193
1194 // C++ 6.4.2.p2:
1195 // Integral promotions are performed (on the switch condition).
1196 //
1197 // A case value unrepresentable by the original switch condition
1198 // type (before the promotion) doesn't make sense, even when it can
1199 // be represented by the promoted type. Therefore we need to find
1200 // the pre-promotion type of the switch condition.
1201 const Expr *CondExprBeforePromotion = CondExpr;
1202 QualType CondTypeBeforePromotion =
1203 GetTypeBeforeIntegralPromotion(CondExprBeforePromotion);
1204
1205 // Get the bitwidth of the switched-on value after promotions. We must
1206 // convert the integer case values to this width before comparison.
1207 bool HasDependentValue
1208 = CondExpr->isTypeDependent() || CondExpr->isValueDependent();
1209 unsigned CondWidth = HasDependentValue ? 0 : Context.getIntWidth(CondType);
1210 bool CondIsSigned = CondType->isSignedIntegerOrEnumerationType();
1211
1212 // Get the width and signedness that the condition might actually have, for
1213 // warning purposes.
1214 // FIXME: Grab an IntRange for the condition rather than using the unpromoted
1215 // type.
1216 unsigned CondWidthBeforePromotion
1217 = HasDependentValue ? 0 : Context.getIntWidth(CondTypeBeforePromotion);
1218 bool CondIsSignedBeforePromotion
1219 = CondTypeBeforePromotion->isSignedIntegerOrEnumerationType();
1220
1221 // Accumulate all of the case values in a vector so that we can sort them
1222 // and detect duplicates. This vector contains the APInt for the case after
1223 // it has been converted to the condition type.
1224 typedef SmallVector<std::pair<llvm::APSInt, CaseStmt*>, 64> CaseValsTy;
1225 CaseValsTy CaseVals;
1226
1227 // Keep track of any GNU case ranges we see. The APSInt is the low value.
1228 typedef std::vector<std::pair<llvm::APSInt, CaseStmt*> > CaseRangesTy;
1229 CaseRangesTy CaseRanges;
1230
1231 DefaultStmt *TheDefaultStmt = nullptr;
1232
1233 bool CaseListIsErroneous = false;
1234
1235 for (SwitchCase *SC = SS->getSwitchCaseList(); SC && !HasDependentValue;
1236 SC = SC->getNextSwitchCase()) {
1237
1238 if (DefaultStmt *DS = dyn_cast<DefaultStmt>(SC)) {
1239 if (TheDefaultStmt) {
1240 Diag(DS->getDefaultLoc(), diag::err_multiple_default_labels_defined);
1241 Diag(TheDefaultStmt->getDefaultLoc(), diag::note_duplicate_case_prev);
1242
1243 // FIXME: Remove the default statement from the switch block so that
1244 // we'll return a valid AST. This requires recursing down the AST and
1245 // finding it, not something we are set up to do right now. For now,
1246 // just lop the entire switch stmt out of the AST.
1247 CaseListIsErroneous = true;
1248 }
1249 TheDefaultStmt = DS;
1250
1251 } else {
1252 CaseStmt *CS = cast<CaseStmt>(SC);
1253
1254 Expr *Lo = CS->getLHS();
1255
1256 if (Lo->isValueDependent()) {
1257 HasDependentValue = true;
1258 break;
1259 }
1260
1261 // We already verified that the expression has a constant value;
1262 // get that value (prior to conversions).
1263 const Expr *LoBeforePromotion = Lo;
1264 GetTypeBeforeIntegralPromotion(LoBeforePromotion);
1265 llvm::APSInt LoVal = LoBeforePromotion->EvaluateKnownConstInt(Context);
1266
1267 // Check the unconverted value is within the range of possible values of
1268 // the switch expression.
1269 checkCaseValue(*this, Lo->getBeginLoc(), LoVal, CondWidthBeforePromotion,
1270 CondIsSignedBeforePromotion);
1271
1272 // FIXME: This duplicates the check performed for warn_not_in_enum below.
1273 checkEnumTypesInSwitchStmt(*this, CondExprBeforePromotion,
1274 LoBeforePromotion);
1275
1276 // Convert the value to the same width/sign as the condition.
1277 AdjustAPSInt(LoVal, CondWidth, CondIsSigned);
1278
1279 // If this is a case range, remember it in CaseRanges, otherwise CaseVals.
1280 if (CS->getRHS()) {
1281 if (CS->getRHS()->isValueDependent()) {
1282 HasDependentValue = true;
1283 break;
1284 }
1285 CaseRanges.push_back(std::make_pair(LoVal, CS));
1286 } else
1287 CaseVals.push_back(std::make_pair(LoVal, CS));
1288 }
1289 }
1290
1291 if (!HasDependentValue) {
1292 // If we don't have a default statement, check whether the
1293 // condition is constant.
1294 llvm::APSInt ConstantCondValue;
1295 bool HasConstantCond = false;
1296 if (!TheDefaultStmt) {
1297 Expr::EvalResult Result;
1298 HasConstantCond = CondExpr->EvaluateAsInt(Result, Context,
1299 Expr::SE_AllowSideEffects);
1300 if (Result.Val.isInt())
1301 ConstantCondValue = Result.Val.getInt();
1302 assert(!HasConstantCond ||(static_cast<void> (0))
1303 (ConstantCondValue.getBitWidth() == CondWidth &&(static_cast<void> (0))
1304 ConstantCondValue.isSigned() == CondIsSigned))(static_cast<void> (0));
1305 }
1306 bool ShouldCheckConstantCond = HasConstantCond;
1307
1308 // Sort all the scalar case values so we can easily detect duplicates.
1309 llvm::stable_sort(CaseVals, CmpCaseVals);
1310
1311 if (!CaseVals.empty()) {
1312 for (unsigned i = 0, e = CaseVals.size(); i != e; ++i) {
1313 if (ShouldCheckConstantCond &&
1314 CaseVals[i].first == ConstantCondValue)
1315 ShouldCheckConstantCond = false;
1316
1317 if (i != 0 && CaseVals[i].first == CaseVals[i-1].first) {
1318 // If we have a duplicate, report it.
1319 // First, determine if either case value has a name
1320 StringRef PrevString, CurrString;
1321 Expr *PrevCase = CaseVals[i-1].second->getLHS()->IgnoreParenCasts();
1322 Expr *CurrCase = CaseVals[i].second->getLHS()->IgnoreParenCasts();
1323 if (DeclRefExpr *DeclRef = dyn_cast<DeclRefExpr>(PrevCase)) {
1324 PrevString = DeclRef->getDecl()->getName();
1325 }
1326 if (DeclRefExpr *DeclRef = dyn_cast<DeclRefExpr>(CurrCase)) {
1327 CurrString = DeclRef->getDecl()->getName();
1328 }
1329 SmallString<16> CaseValStr;
1330 CaseVals[i-1].first.toString(CaseValStr);
1331
1332 if (PrevString == CurrString)
1333 Diag(CaseVals[i].second->getLHS()->getBeginLoc(),
1334 diag::err_duplicate_case)
1335 << (PrevString.empty() ? CaseValStr.str() : PrevString);
1336 else
1337 Diag(CaseVals[i].second->getLHS()->getBeginLoc(),
1338 diag::err_duplicate_case_differing_expr)
1339 << (PrevString.empty() ? CaseValStr.str() : PrevString)
1340 << (CurrString.empty() ? CaseValStr.str() : CurrString)
1341 << CaseValStr;
1342
1343 Diag(CaseVals[i - 1].second->getLHS()->getBeginLoc(),
1344 diag::note_duplicate_case_prev);
1345 // FIXME: We really want to remove the bogus case stmt from the
1346 // substmt, but we have no way to do this right now.
1347 CaseListIsErroneous = true;
1348 }
1349 }
1350 }
1351
1352 // Detect duplicate case ranges, which usually don't exist at all in
1353 // the first place.
1354 if (!CaseRanges.empty()) {
1355 // Sort all the case ranges by their low value so we can easily detect
1356 // overlaps between ranges.
1357 llvm::stable_sort(CaseRanges);
1358
1359 // Scan the ranges, computing the high values and removing empty ranges.
1360 std::vector<llvm::APSInt> HiVals;
1361 for (unsigned i = 0, e = CaseRanges.size(); i != e; ++i) {
1362 llvm::APSInt &LoVal = CaseRanges[i].first;
1363 CaseStmt *CR = CaseRanges[i].second;
1364 Expr *Hi = CR->getRHS();
1365
1366 const Expr *HiBeforePromotion = Hi;
1367 GetTypeBeforeIntegralPromotion(HiBeforePromotion);
1368 llvm::APSInt HiVal = HiBeforePromotion->EvaluateKnownConstInt(Context);
1369
1370 // Check the unconverted value is within the range of possible values of
1371 // the switch expression.
1372 checkCaseValue(*this, Hi->getBeginLoc(), HiVal,
1373 CondWidthBeforePromotion, CondIsSignedBeforePromotion);
1374
1375 // Convert the value to the same width/sign as the condition.
1376 AdjustAPSInt(HiVal, CondWidth, CondIsSigned);
1377
1378 // If the low value is bigger than the high value, the case is empty.
1379 if (LoVal > HiVal) {
1380 Diag(CR->getLHS()->getBeginLoc(), diag::warn_case_empty_range)
1381 << SourceRange(CR->getLHS()->getBeginLoc(), Hi->getEndLoc());
1382 CaseRanges.erase(CaseRanges.begin()+i);
1383 --i;
1384 --e;
1385 continue;
1386 }
1387
1388 if (ShouldCheckConstantCond &&
1389 LoVal <= ConstantCondValue &&
1390 ConstantCondValue <= HiVal)
1391 ShouldCheckConstantCond = false;
1392
1393 HiVals.push_back(HiVal);
1394 }
1395
1396 // Rescan the ranges, looking for overlap with singleton values and other
1397 // ranges. Since the range list is sorted, we only need to compare case
1398 // ranges with their neighbors.
1399 for (unsigned i = 0, e = CaseRanges.size(); i != e; ++i) {
1400 llvm::APSInt &CRLo = CaseRanges[i].first;
1401 llvm::APSInt &CRHi = HiVals[i];
1402 CaseStmt *CR = CaseRanges[i].second;
1403
1404 // Check to see whether the case range overlaps with any
1405 // singleton cases.
1406 CaseStmt *OverlapStmt = nullptr;
1407 llvm::APSInt OverlapVal(32);
1408
1409 // Find the smallest value >= the lower bound. If I is in the
1410 // case range, then we have overlap.
1411 CaseValsTy::iterator I =
1412 llvm::lower_bound(CaseVals, CRLo, CaseCompareFunctor());
1413 if (I != CaseVals.end() && I->first < CRHi) {
1414 OverlapVal = I->first; // Found overlap with scalar.
1415 OverlapStmt = I->second;
1416 }
1417
1418 // Find the smallest value bigger than the upper bound.
1419 I = std::upper_bound(I, CaseVals.end(), CRHi, CaseCompareFunctor());
1420 if (I != CaseVals.begin() && (I-1)->first >= CRLo) {
1421 OverlapVal = (I-1)->first; // Found overlap with scalar.
1422 OverlapStmt = (I-1)->second;
1423 }
1424
1425 // Check to see if this case stmt overlaps with the subsequent
1426 // case range.
1427 if (i && CRLo <= HiVals[i-1]) {
1428 OverlapVal = HiVals[i-1]; // Found overlap with range.
1429 OverlapStmt = CaseRanges[i-1].second;
1430 }
1431
1432 if (OverlapStmt) {
1433 // If we have a duplicate, report it.
1434 Diag(CR->getLHS()->getBeginLoc(), diag::err_duplicate_case)
1435 << toString(OverlapVal, 10);
1436 Diag(OverlapStmt->getLHS()->getBeginLoc(),
1437 diag::note_duplicate_case_prev);
1438 // FIXME: We really want to remove the bogus case stmt from the
1439 // substmt, but we have no way to do this right now.
1440 CaseListIsErroneous = true;
1441 }
1442 }
1443 }
1444
1445 // Complain if we have a constant condition and we didn't find a match.
1446 if (!CaseListIsErroneous && !CaseListIsIncomplete &&
1447 ShouldCheckConstantCond) {
1448 // TODO: it would be nice if we printed enums as enums, chars as
1449 // chars, etc.
1450 Diag(CondExpr->getExprLoc(), diag::warn_missing_case_for_condition)
1451 << toString(ConstantCondValue, 10)
1452 << CondExpr->getSourceRange();
1453 }
1454
1455 // Check to see if switch is over an Enum and handles all of its
1456 // values. We only issue a warning if there is not 'default:', but
1457 // we still do the analysis to preserve this information in the AST
1458 // (which can be used by flow-based analyes).
1459 //
1460 const EnumType *ET = CondTypeBeforePromotion->getAs<EnumType>();
1461
1462 // If switch has default case, then ignore it.
1463 if (!CaseListIsErroneous && !CaseListIsIncomplete && !HasConstantCond &&
1464 ET && ET->getDecl()->isCompleteDefinition() &&
1465 !empty(ET->getDecl()->enumerators())) {
1466 const EnumDecl *ED = ET->getDecl();
1467 EnumValsTy EnumVals;
1468
1469 // Gather all enum values, set their type and sort them,
1470 // allowing easier comparison with CaseVals.
1471 for (auto *EDI : ED->enumerators()) {
1472 llvm::APSInt Val = EDI->getInitVal();
1473 AdjustAPSInt(Val, CondWidth, CondIsSigned);
1474 EnumVals.push_back(std::make_pair(Val, EDI));
1475 }
1476 llvm::stable_sort(EnumVals, CmpEnumVals);
1477 auto EI = EnumVals.begin(), EIEnd =
1478 std::unique(EnumVals.begin(), EnumVals.end(), EqEnumVals);
1479
1480 // See which case values aren't in enum.
1481 for (CaseValsTy::const_iterator CI = CaseVals.begin();
1482 CI != CaseVals.end(); CI++) {
1483 Expr *CaseExpr = CI->second->getLHS();
1484 if (ShouldDiagnoseSwitchCaseNotInEnum(*this, ED, CaseExpr, EI, EIEnd,
1485 CI->first))
1486 Diag(CaseExpr->getExprLoc(), diag::warn_not_in_enum)
1487 << CondTypeBeforePromotion;
1488 }
1489
1490 // See which of case ranges aren't in enum
1491 EI = EnumVals.begin();
1492 for (CaseRangesTy::const_iterator RI = CaseRanges.begin();
1493 RI != CaseRanges.end(); RI++) {
1494 Expr *CaseExpr = RI->second->getLHS();
1495 if (ShouldDiagnoseSwitchCaseNotInEnum(*this, ED, CaseExpr, EI, EIEnd,
1496 RI->first))
1497 Diag(CaseExpr->getExprLoc(), diag::warn_not_in_enum)
1498 << CondTypeBeforePromotion;
1499
1500 llvm::APSInt Hi =
1501 RI->second->getRHS()->EvaluateKnownConstInt(Context);
1502 AdjustAPSInt(Hi, CondWidth, CondIsSigned);
1503
1504 CaseExpr = RI->second->getRHS();
1505 if (ShouldDiagnoseSwitchCaseNotInEnum(*this, ED, CaseExpr, EI, EIEnd,
1506 Hi))
1507 Diag(CaseExpr->getExprLoc(), diag::warn_not_in_enum)
1508 << CondTypeBeforePromotion;
1509 }
1510
1511 // Check which enum vals aren't in switch
1512 auto CI = CaseVals.begin();
1513 auto RI = CaseRanges.begin();
1514 bool hasCasesNotInSwitch = false;
1515
1516 SmallVector<DeclarationName,8> UnhandledNames;
1517
1518 for (EI = EnumVals.begin(); EI != EIEnd; EI++) {
1519 // Don't warn about omitted unavailable EnumConstantDecls.
1520 switch (EI->second->getAvailability()) {
1521 case AR_Deprecated:
1522 // Omitting a deprecated constant is ok; it should never materialize.
1523 case AR_Unavailable:
1524 continue;
1525
1526 case AR_NotYetIntroduced:
1527 // Partially available enum constants should be present. Note that we
1528 // suppress -Wunguarded-availability diagnostics for such uses.
1529 case AR_Available:
1530 break;
1531 }
1532
1533 if (EI->second->hasAttr<UnusedAttr>())
1534 continue;
1535
1536 // Drop unneeded case values
1537 while (CI != CaseVals.end() && CI->first < EI->first)
1538 CI++;
1539
1540 if (CI != CaseVals.end() && CI->first == EI->first)
1541 continue;
1542
1543 // Drop unneeded case ranges
1544 for (; RI != CaseRanges.end(); RI++) {
1545 llvm::APSInt Hi =
1546 RI->second->getRHS()->EvaluateKnownConstInt(Context);
1547 AdjustAPSInt(Hi, CondWidth, CondIsSigned);
1548 if (EI->first <= Hi)
1549 break;
1550 }
1551
1552 if (RI == CaseRanges.end() || EI->first < RI->first) {
1553 hasCasesNotInSwitch = true;
1554 UnhandledNames.push_back(EI->second->getDeclName());
1555 }
1556 }
1557
1558 if (TheDefaultStmt && UnhandledNames.empty() && ED->isClosedNonFlag())
1559 Diag(TheDefaultStmt->getDefaultLoc(), diag::warn_unreachable_default);
1560
1561 // Produce a nice diagnostic if multiple values aren't handled.
1562 if (!UnhandledNames.empty()) {
1563 auto DB = Diag(CondExpr->getExprLoc(), TheDefaultStmt
1564 ? diag::warn_def_missing_case
1565 : diag::warn_missing_case)
1566 << CondExpr->getSourceRange() << (int)UnhandledNames.size();
1567
1568 for (size_t I = 0, E = std::min(UnhandledNames.size(), (size_t)3);
1569 I != E; ++I)
1570 DB << UnhandledNames[I];
1571 }
1572
1573 if (!hasCasesNotInSwitch)
1574 SS->setAllEnumCasesCovered();
1575 }
1576 }
1577
1578 if (BodyStmt)
1579 DiagnoseEmptyStmtBody(CondExpr->getEndLoc(), BodyStmt,
1580 diag::warn_empty_switch_body);
1581
1582 // FIXME: If the case list was broken is some way, we don't have a good system
1583 // to patch it up. Instead, just return the whole substmt as broken.
1584 if (CaseListIsErroneous)
1585 return StmtError();
1586
1587 return SS;
1588}
1589
1590void
1591Sema::DiagnoseAssignmentEnum(QualType DstType, QualType SrcType,
1592 Expr *SrcExpr) {
1593 if (Diags.isIgnored(diag::warn_not_in_enum_assignment, SrcExpr->getExprLoc()))
1594 return;
1595
1596 if (const EnumType *ET = DstType->getAs<EnumType>())
1597 if (!Context.hasSameUnqualifiedType(SrcType, DstType) &&
1598 SrcType->isIntegerType()) {
1599 if (!SrcExpr->isTypeDependent() && !SrcExpr->isValueDependent() &&
1600 SrcExpr->isIntegerConstantExpr(Context)) {
1601 // Get the bitwidth of the enum value before promotions.
1602 unsigned DstWidth = Context.getIntWidth(DstType);
1603 bool DstIsSigned = DstType->isSignedIntegerOrEnumerationType();
1604
1605 llvm::APSInt RhsVal = SrcExpr->EvaluateKnownConstInt(Context);
1606 AdjustAPSInt(RhsVal, DstWidth, DstIsSigned);
1607 const EnumDecl *ED = ET->getDecl();
1608
1609 if (!ED->isClosed())
1610 return;
1611
1612 if (ED->hasAttr<FlagEnumAttr>()) {
1613 if (!IsValueInFlagEnum(ED, RhsVal, true))
1614 Diag(SrcExpr->getExprLoc(), diag::warn_not_in_enum_assignment)
1615 << DstType.getUnqualifiedType();
1616 } else {
1617 typedef SmallVector<std::pair<llvm::APSInt, EnumConstantDecl *>, 64>
1618 EnumValsTy;
1619 EnumValsTy EnumVals;
1620
1621 // Gather all enum values, set their type and sort them,
1622 // allowing easier comparison with rhs constant.
1623 for (auto *EDI : ED->enumerators()) {
1624 llvm::APSInt Val = EDI->getInitVal();
1625 AdjustAPSInt(Val, DstWidth, DstIsSigned);
1626 EnumVals.push_back(std::make_pair(Val, EDI));
1627 }
1628 if (EnumVals.empty())
1629 return;
1630 llvm::stable_sort(EnumVals, CmpEnumVals);
1631 EnumValsTy::iterator EIend =
1632 std::unique(EnumVals.begin(), EnumVals.end(), EqEnumVals);
1633
1634 // See which values aren't in the enum.
1635 EnumValsTy::const_iterator EI = EnumVals.begin();
1636 while (EI != EIend && EI->first < RhsVal)
1637 EI++;
1638 if (EI == EIend || EI->first != RhsVal) {
1639 Diag(SrcExpr->getExprLoc(), diag::warn_not_in_enum_assignment)
1640 << DstType.getUnqualifiedType();
1641 }
1642 }
1643 }
1644 }
1645}
1646
1647StmtResult Sema::ActOnWhileStmt(SourceLocation WhileLoc,
1648 SourceLocation LParenLoc, ConditionResult Cond,
1649 SourceLocation RParenLoc, Stmt *Body) {
1650 if (Cond.isInvalid())
1651 return StmtError();
1652
1653 auto CondVal = Cond.get();
1654 CheckBreakContinueBinding(CondVal.second);
1655
1656 if (CondVal.second &&
1657 !Diags.isIgnored(diag::warn_comma_operator, CondVal.second->getExprLoc()))
1658 CommaVisitor(*this).Visit(CondVal.second);
1659
1660 if (isa<NullStmt>(Body))
1661 getCurCompoundScope().setHasEmptyLoopBodies();
1662
1663 return WhileStmt::Create(Context, CondVal.first, CondVal.second, Body,
1664 WhileLoc, LParenLoc, RParenLoc);
1665}
1666
1667StmtResult
1668Sema::ActOnDoStmt(SourceLocation DoLoc, Stmt *Body,
1669 SourceLocation WhileLoc, SourceLocation CondLParen,
1670 Expr *Cond, SourceLocation CondRParen) {
1671 assert(Cond && "ActOnDoStmt(): missing expression")(static_cast<void> (0));
1672
1673 CheckBreakContinueBinding(Cond);
1674 ExprResult CondResult = CheckBooleanCondition(DoLoc, Cond);
1675 if (CondResult.isInvalid())
1676 return StmtError();
1677 Cond = CondResult.get();
1678
1679 CondResult = ActOnFinishFullExpr(Cond, DoLoc, /*DiscardedValue*/ false);
1680 if (CondResult.isInvalid())
1681 return StmtError();
1682 Cond = CondResult.get();
1683
1684 // Only call the CommaVisitor for C89 due to differences in scope flags.
1685 if (Cond && !getLangOpts().C99 && !getLangOpts().CPlusPlus &&
1686 !Diags.isIgnored(diag::warn_comma_operator, Cond->getExprLoc()))
1687 CommaVisitor(*this).Visit(Cond);
1688
1689 return new (Context) DoStmt(Body, Cond, DoLoc, WhileLoc, CondRParen);
1690}
1691
1692namespace {
1693 // Use SetVector since the diagnostic cares about the ordering of the Decl's.
1694 using DeclSetVector =
1695 llvm::SetVector<VarDecl *, llvm::SmallVector<VarDecl *, 8>,
1696 llvm::SmallPtrSet<VarDecl *, 8>>;
1697
1698 // This visitor will traverse a conditional statement and store all
1699 // the evaluated decls into a vector. Simple is set to true if none
1700 // of the excluded constructs are used.
1701 class DeclExtractor : public EvaluatedExprVisitor<DeclExtractor> {
1702 DeclSetVector &Decls;
1703 SmallVectorImpl<SourceRange> &Ranges;
1704 bool Simple;
1705 public:
1706 typedef EvaluatedExprVisitor<DeclExtractor> Inherited;
1707
1708 DeclExtractor(Sema &S, DeclSetVector &Decls,
1709 SmallVectorImpl<SourceRange> &Ranges) :
1710 Inherited(S.Context),
1711 Decls(Decls),
1712 Ranges(Ranges),
1713 Simple(true) {}
1714
1715 bool isSimple() { return Simple; }
1716
1717 // Replaces the method in EvaluatedExprVisitor.
1718 void VisitMemberExpr(MemberExpr* E) {
1719 Simple = false;
1720 }
1721
1722 // Any Stmt not explicitly listed will cause the condition to be marked
1723 // complex.
1724 void VisitStmt(Stmt *S) { Simple = false; }
1725
1726 void VisitBinaryOperator(BinaryOperator *E) {
1727 Visit(E->getLHS());
1728 Visit(E->getRHS());
1729 }
1730
1731 void VisitCastExpr(CastExpr *E) {
1732 Visit(E->getSubExpr());
1733 }
1734
1735 void VisitUnaryOperator(UnaryOperator *E) {
1736 // Skip checking conditionals with derefernces.
1737 if (E->getOpcode() == UO_Deref)
1738 Simple = false;
1739 else
1740 Visit(E->getSubExpr());
1741 }
1742
1743 void VisitConditionalOperator(ConditionalOperator *E) {
1744 Visit(E->getCond());
1745 Visit(E->getTrueExpr());
1746 Visit(E->getFalseExpr());
1747 }
1748
1749 void VisitParenExpr(ParenExpr *E) {
1750 Visit(E->getSubExpr());
1751 }
1752
1753 void VisitBinaryConditionalOperator(BinaryConditionalOperator *E) {
1754 Visit(E->getOpaqueValue()->getSourceExpr());
1755 Visit(E->getFalseExpr());
1756 }
1757
1758 void VisitIntegerLiteral(IntegerLiteral *E) { }
1759 void VisitFloatingLiteral(FloatingLiteral *E) { }
1760 void VisitCXXBoolLiteralExpr(CXXBoolLiteralExpr *E) { }
1761 void VisitCharacterLiteral(CharacterLiteral *E) { }
1762 void VisitGNUNullExpr(GNUNullExpr *E) { }
1763 void VisitImaginaryLiteral(ImaginaryLiteral *E) { }
1764
1765 void VisitDeclRefExpr(DeclRefExpr *E) {
1766 VarDecl *VD = dyn_cast<VarDecl>(E->getDecl());
1767 if (!VD) {
1768 // Don't allow unhandled Decl types.
1769 Simple = false;
1770 return;
1771 }
1772
1773 Ranges.push_back(E->getSourceRange());
1774
1775 Decls.insert(VD);
1776 }
1777
1778 }; // end class DeclExtractor
1779
1780 // DeclMatcher checks to see if the decls are used in a non-evaluated
1781 // context.
1782 class DeclMatcher : public EvaluatedExprVisitor<DeclMatcher> {
1783 DeclSetVector &Decls;
1784 bool FoundDecl;
1785
1786 public:
1787 typedef EvaluatedExprVisitor<DeclMatcher> Inherited;
1788
1789 DeclMatcher(Sema &S, DeclSetVector &Decls, Stmt *Statement) :
1790 Inherited(S.Context), Decls(Decls), FoundDecl(false) {
1791 if (!Statement) return;
1792
1793 Visit(Statement);
1794 }
1795
1796 void VisitReturnStmt(ReturnStmt *S) {
1797 FoundDecl = true;
1798 }
1799
1800 void VisitBreakStmt(BreakStmt *S) {
1801 FoundDecl = true;
1802 }
1803
1804 void VisitGotoStmt(GotoStmt *S) {
1805 FoundDecl = true;
1806 }
1807
1808 void VisitCastExpr(CastExpr *E) {
1809 if (E->getCastKind() == CK_LValueToRValue)
1810 CheckLValueToRValueCast(E->getSubExpr());
1811 else
1812 Visit(E->getSubExpr());
1813 }
1814
1815 void CheckLValueToRValueCast(Expr *E) {
1816 E = E->IgnoreParenImpCasts();
1817
1818 if (isa<DeclRefExpr>(E)) {
1819 return;
1820 }
1821
1822 if (ConditionalOperator *CO = dyn_cast<ConditionalOperator>(E)) {
1823 Visit(CO->getCond());
1824 CheckLValueToRValueCast(CO->getTrueExpr());
1825 CheckLValueToRValueCast(CO->getFalseExpr());
1826 return;
1827 }
1828
1829 if (BinaryConditionalOperator *BCO =
1830 dyn_cast<BinaryConditionalOperator>(E)) {
1831 CheckLValueToRValueCast(BCO->getOpaqueValue()->getSourceExpr());
1832 CheckLValueToRValueCast(BCO->getFalseExpr());
1833 return;
1834 }
1835
1836 Visit(E);
1837 }
1838
1839 void VisitDeclRefExpr(DeclRefExpr *E) {
1840 if (VarDecl *VD = dyn_cast<VarDecl>(E->getDecl()))
1841 if (Decls.count(VD))
1842 FoundDecl = true;
1843 }
1844
1845 void VisitPseudoObjectExpr(PseudoObjectExpr *POE) {
1846 // Only need to visit the semantics for POE.
1847 // SyntaticForm doesn't really use the Decal.
1848 for (auto *S : POE->semantics()) {
1849 if (auto *OVE = dyn_cast<OpaqueValueExpr>(S))
1850 // Look past the OVE into the expression it binds.
1851 Visit(OVE->getSourceExpr());
1852 else
1853 Visit(S);
1854 }
1855 }
1856
1857 bool FoundDeclInUse() { return FoundDecl; }
1858
1859 }; // end class DeclMatcher
1860
1861 void CheckForLoopConditionalStatement(Sema &S, Expr *Second,
1862 Expr *Third, Stmt *Body) {
1863 // Condition is empty
1864 if (!Second) return;
1865
1866 if (S.Diags.isIgnored(diag::warn_variables_not_in_loop_body,
1867 Second->getBeginLoc()))
1868 return;
1869
1870 PartialDiagnostic PDiag = S.PDiag(diag::warn_variables_not_in_loop_body);
1871 DeclSetVector Decls;
1872 SmallVector<SourceRange, 10> Ranges;
1873 DeclExtractor DE(S, Decls, Ranges);
1874 DE.Visit(Second);
1875
1876 // Don't analyze complex conditionals.
1877 if (!DE.isSimple()) return;
1878
1879 // No decls found.
1880 if (Decls.size() == 0) return;
1881
1882 // Don't warn on volatile, static, or global variables.
1883 for (auto *VD : Decls)
1884 if (VD->getType().isVolatileQualified() || VD->hasGlobalStorage())
1885 return;
1886
1887 if (DeclMatcher(S, Decls, Second).FoundDeclInUse() ||
1888 DeclMatcher(S, Decls, Third).FoundDeclInUse() ||
1889 DeclMatcher(S, Decls, Body).FoundDeclInUse())
1890 return;
1891
1892 // Load decl names into diagnostic.
1893 if (Decls.size() > 4) {
1894 PDiag << 0;
1895 } else {
1896 PDiag << (unsigned)Decls.size();
1897 for (auto *VD : Decls)
1898 PDiag << VD->getDeclName();
1899 }
1900
1901 for (auto Range : Ranges)
1902 PDiag << Range;
1903
1904 S.Diag(Ranges.begin()->getBegin(), PDiag);
1905 }
1906
1907 // If Statement is an incemement or decrement, return true and sets the
1908 // variables Increment and DRE.
1909 bool ProcessIterationStmt(Sema &S, Stmt* Statement, bool &Increment,
1910 DeclRefExpr *&DRE) {
1911 if (auto Cleanups = dyn_cast<ExprWithCleanups>(Statement))
1912 if (!Cleanups->cleanupsHaveSideEffects())
1913 Statement = Cleanups->getSubExpr();
1914
1915 if (UnaryOperator *UO = dyn_cast<UnaryOperator>(Statement)) {
1916 switch (UO->getOpcode()) {
1917 default: return false;
1918 case UO_PostInc:
1919 case UO_PreInc:
1920 Increment = true;
1921 break;
1922 case UO_PostDec:
1923 case UO_PreDec:
1924 Increment = false;
1925 break;
1926 }
1927 DRE = dyn_cast<DeclRefExpr>(UO->getSubExpr());
1928 return DRE;
1929 }
1930
1931 if (CXXOperatorCallExpr *Call = dyn_cast<CXXOperatorCallExpr>(Statement)) {
1932 FunctionDecl *FD = Call->getDirectCallee();
1933 if (!FD || !FD->isOverloadedOperator()) return false;
1934 switch (FD->getOverloadedOperator()) {
1935 default: return false;
1936 case OO_PlusPlus:
1937 Increment = true;
1938 break;
1939 case OO_MinusMinus:
1940 Increment = false;
1941 break;
1942 }
1943 DRE = dyn_cast<DeclRefExpr>(Call->getArg(0));
1944 return DRE;
1945 }
1946
1947 return false;
1948 }
1949
1950 // A visitor to determine if a continue or break statement is a
1951 // subexpression.
1952 class BreakContinueFinder : public ConstEvaluatedExprVisitor<BreakContinueFinder> {
1953 SourceLocation BreakLoc;
1954 SourceLocation ContinueLoc;
1955 bool InSwitch = false;
1956
1957 public:
1958 BreakContinueFinder(Sema &S, const Stmt* Body) :
1959 Inherited(S.Context) {
1960 Visit(Body);
1961 }
1962
1963 typedef ConstEvaluatedExprVisitor<BreakContinueFinder> Inherited;
1964
1965 void VisitContinueStmt(const ContinueStmt* E) {
1966 ContinueLoc = E->getContinueLoc();
1967 }
1968
1969 void VisitBreakStmt(const BreakStmt* E) {
1970 if (!InSwitch)
1971 BreakLoc = E->getBreakLoc();
1972 }
1973
1974 void VisitSwitchStmt(const SwitchStmt* S) {
1975 if (const Stmt *Init = S->getInit())
1976 Visit(Init);
1977 if (const Stmt *CondVar = S->getConditionVariableDeclStmt())
1978 Visit(CondVar);
1979 if (const Stmt *Cond = S->getCond())
1980 Visit(Cond);
1981
1982 // Don't return break statements from the body of a switch.
1983 InSwitch = true;
1984 if (const Stmt *Body = S->getBody())
1985 Visit(Body);
1986 InSwitch = false;
1987 }
1988
1989 void VisitForStmt(const ForStmt *S) {
1990 // Only visit the init statement of a for loop; the body
1991 // has a different break/continue scope.
1992 if (const Stmt *Init = S->getInit())
1993 Visit(Init);
1994 }
1995
1996 void VisitWhileStmt(const WhileStmt *) {
1997 // Do nothing; the children of a while loop have a different
1998 // break/continue scope.
1999 }
2000
2001 void VisitDoStmt(const DoStmt *) {
2002 // Do nothing; the children of a while loop have a different
2003 // break/continue scope.
2004 }
2005
2006 void VisitCXXForRangeStmt(const CXXForRangeStmt *S) {
2007 // Only visit the initialization of a for loop; the body
2008 // has a different break/continue scope.
2009 if (const Stmt *Init = S->getInit())
2010 Visit(Init);
2011 if (const Stmt *Range = S->getRangeStmt())
2012 Visit(Range);
2013 if (const Stmt *Begin = S->getBeginStmt())
2014 Visit(Begin);
2015 if (const Stmt *End = S->getEndStmt())
2016 Visit(End);
2017 }
2018
2019 void VisitObjCForCollectionStmt(const ObjCForCollectionStmt *S) {
2020 // Only visit the initialization of a for loop; the body
2021 // has a different break/continue scope.
2022 if (const Stmt *Element = S->getElement())
2023 Visit(Element);
2024 if (const Stmt *Collection = S->getCollection())
2025 Visit(Collection);
2026 }
2027
2028 bool ContinueFound() { return ContinueLoc.isValid(); }
2029 bool BreakFound() { return BreakLoc.isValid(); }
2030 SourceLocation GetContinueLoc() { return ContinueLoc; }
2031 SourceLocation GetBreakLoc() { return BreakLoc; }
2032
2033 }; // end class BreakContinueFinder
2034
2035 // Emit a warning when a loop increment/decrement appears twice per loop
2036 // iteration. The conditions which trigger this warning are:
2037 // 1) The last statement in the loop body and the third expression in the
2038 // for loop are both increment or both decrement of the same variable
2039 // 2) No continue statements in the loop body.
2040 void CheckForRedundantIteration(Sema &S, Expr *Third, Stmt *Body) {
2041 // Return when there is nothing to check.
2042 if (!Body || !Third) return;
2043
2044 if (S.Diags.isIgnored(diag::warn_redundant_loop_iteration,
2045 Third->getBeginLoc()))
2046 return;
2047
2048 // Get the last statement from the loop body.
2049 CompoundStmt *CS = dyn_cast<CompoundStmt>(Body);
2050 if (!CS || CS->body_empty()) return;
2051 Stmt *LastStmt = CS->body_back();
2052 if (!LastStmt) return;
2053
2054 bool LoopIncrement, LastIncrement;
2055 DeclRefExpr *LoopDRE, *LastDRE;
2056
2057 if (!ProcessIterationStmt(S, Third, LoopIncrement, LoopDRE)) return;
2058 if (!ProcessIterationStmt(S, LastStmt, LastIncrement, LastDRE)) return;
2059
2060 // Check that the two statements are both increments or both decrements
2061 // on the same variable.
2062 if (LoopIncrement != LastIncrement ||
2063 LoopDRE->getDecl() != LastDRE->getDecl()) return;
2064
2065 if (BreakContinueFinder(S, Body).ContinueFound()) return;
2066
2067 S.Diag(LastDRE->getLocation(), diag::warn_redundant_loop_iteration)
2068 << LastDRE->getDecl() << LastIncrement;
2069 S.Diag(LoopDRE->getLocation(), diag::note_loop_iteration_here)
2070 << LoopIncrement;
2071 }
2072
2073} // end namespace
2074
2075
2076void Sema::CheckBreakContinueBinding(Expr *E) {
2077 if (!E || getLangOpts().CPlusPlus)
2078 return;
2079 BreakContinueFinder BCFinder(*this, E);
2080 Scope *BreakParent = CurScope->getBreakParent();
2081 if (BCFinder.BreakFound() && BreakParent) {
2082 if (BreakParent->getFlags() & Scope::SwitchScope) {
2083 Diag(BCFinder.GetBreakLoc(), diag::warn_break_binds_to_switch);
2084 } else {
2085 Diag(BCFinder.GetBreakLoc(), diag::warn_loop_ctrl_binds_to_inner)
2086 << "break";
2087 }
2088 } else if (BCFinder.ContinueFound() && CurScope->getContinueParent()) {
2089 Diag(BCFinder.GetContinueLoc(), diag::warn_loop_ctrl_binds_to_inner)
2090 << "continue";
2091 }
2092}
2093
2094StmtResult Sema::ActOnForStmt(SourceLocation ForLoc, SourceLocation LParenLoc,
2095 Stmt *First, ConditionResult Second,
2096 FullExprArg third, SourceLocation RParenLoc,
2097 Stmt *Body) {
2098 if (Second.isInvalid())
2099 return StmtError();
2100
2101 if (!getLangOpts().CPlusPlus) {
2102 if (DeclStmt *DS = dyn_cast_or_null<DeclStmt>(First)) {
2103 // C99 6.8.5p3: The declaration part of a 'for' statement shall only
2104 // declare identifiers for objects having storage class 'auto' or
2105 // 'register'.
2106 const Decl *NonVarSeen = nullptr;
2107 bool VarDeclSeen = false;
2108 for (auto *DI : DS->decls()) {
2109 if (VarDecl *VD = dyn_cast<VarDecl>(DI)) {
2110 VarDeclSeen = true;
2111 if (VD->isLocalVarDecl() && !VD->hasLocalStorage()) {
2112 Diag(DI->getLocation(), diag::err_non_local_variable_decl_in_for);
2113 DI->setInvalidDecl();
2114 }
2115 } else if (!NonVarSeen) {
2116 // Keep track of the first non-variable declaration we saw so that
2117 // we can diagnose if we don't see any variable declarations. This
2118 // covers a case like declaring a typedef, function, or structure
2119 // type rather than a variable.
2120 NonVarSeen = DI;
2121 }
2122 }
2123 // Diagnose if we saw a non-variable declaration but no variable
2124 // declarations.
2125 if (NonVarSeen && !VarDeclSeen)
2126 Diag(NonVarSeen->getLocation(), diag::err_non_variable_decl_in_for);
2127 }
2128 }
2129
2130 CheckBreakContinueBinding(Second.get().second);
2131 CheckBreakContinueBinding(third.get());
2132
2133 if (!Second.get().first)
2134 CheckForLoopConditionalStatement(*this, Second.get().second, third.get(),
2135 Body);
2136 CheckForRedundantIteration(*this, third.get(), Body);
2137
2138 if (Second.get().second &&
2139 !Diags.isIgnored(diag::warn_comma_operator,
2140 Second.get().second->getExprLoc()))
2141 CommaVisitor(*this).Visit(Second.get().second);
2142
2143 Expr *Third = third.release().getAs<Expr>();
2144 if (isa<NullStmt>(Body))
2145 getCurCompoundScope().setHasEmptyLoopBodies();
2146
2147 return new (Context)
2148 ForStmt(Context, First, Second.get().second, Second.get().first, Third,
2149 Body, ForLoc, LParenLoc, RParenLoc);
2150}
2151
2152/// In an Objective C collection iteration statement:
2153/// for (x in y)
2154/// x can be an arbitrary l-value expression. Bind it up as a
2155/// full-expression.
2156StmtResult Sema::ActOnForEachLValueExpr(Expr *E) {
2157 // Reduce placeholder expressions here. Note that this rejects the
2158 // use of pseudo-object l-values in this position.
2159 ExprResult result = CheckPlaceholderExpr(E);
2160 if (result.isInvalid()) return StmtError();
2161 E = result.get();
2162
2163 ExprResult FullExpr = ActOnFinishFullExpr(E, /*DiscardedValue*/ false);
2164 if (FullExpr.isInvalid())
2165 return StmtError();
2166 return StmtResult(static_cast<Stmt*>(FullExpr.get()));
2167}
2168
2169ExprResult
2170Sema::CheckObjCForCollectionOperand(SourceLocation forLoc, Expr *collection) {
2171 if (!collection)
2172 return ExprError();
2173
2174 ExprResult result = CorrectDelayedTyposInExpr(collection);
2175 if (!result.isUsable())
2176 return ExprError();
2177 collection = result.get();
2178
2179 // Bail out early if we've got a type-dependent expression.
2180 if (collection->isTypeDependent()) return collection;
2181
2182 // Perform normal l-value conversion.
2183 result = DefaultFunctionArrayLvalueConversion(collection);
2184 if (result.isInvalid())
2185 return ExprError();
2186 collection = result.get();
2187
2188 // The operand needs to have object-pointer type.
2189 // TODO: should we do a contextual conversion?
2190 const ObjCObjectPointerType *pointerType =
2191 collection->getType()->getAs<ObjCObjectPointerType>();
2192 if (!pointerType)
2193 return Diag(forLoc, diag::err_collection_expr_type)
2194 << collection->getType() << collection->getSourceRange();
2195
2196 // Check that the operand provides
2197 // - countByEnumeratingWithState:objects:count:
2198 const ObjCObjectType *objectType = pointerType->getObjectType();
2199 ObjCInterfaceDecl *iface = objectType->getInterface();
2200
2201 // If we have a forward-declared type, we can't do this check.
2202 // Under ARC, it is an error not to have a forward-declared class.
2203 if (iface &&
2204 (getLangOpts().ObjCAutoRefCount
2205 ? RequireCompleteType(forLoc, QualType(objectType, 0),
2206 diag::err_arc_collection_forward, collection)
2207 : !isCompleteType(forLoc, QualType(objectType, 0)))) {
2208 // Otherwise, if we have any useful type information, check that
2209 // the type declares the appropriate method.
2210 } else if (iface || !objectType->qual_empty()) {
2211 IdentifierInfo *selectorIdents[] = {
2212 &Context.Idents.get("countByEnumeratingWithState"),
2213 &Context.Idents.get("objects"),
2214 &Context.Idents.get("count")
2215 };
2216 Selector selector = Context.Selectors.getSelector(3, &selectorIdents[0]);
2217
2218 ObjCMethodDecl *method = nullptr;
2219
2220 // If there's an interface, look in both the public and private APIs.
2221 if (iface) {
2222 method = iface->lookupInstanceMethod(selector);
2223 if (!method) method = iface->lookupPrivateMethod(selector);
2224 }
2225
2226 // Also check protocol qualifiers.
2227 if (!method)
2228 method = LookupMethodInQualifiedType(selector, pointerType,
2229 /*instance*/ true);
2230
2231 // If we didn't find it anywhere, give up.
2232 if (!method) {
2233 Diag(forLoc, diag::warn_collection_expr_type)
2234 << collection->getType() << selector << collection->getSourceRange();
2235 }
2236
2237 // TODO: check for an incompatible signature?
2238 }
2239
2240 // Wrap up any cleanups in the expression.
2241 return collection;
2242}
2243
2244StmtResult
2245Sema::ActOnObjCForCollectionStmt(SourceLocation ForLoc,
2246 Stmt *First, Expr *collection,
2247 SourceLocation RParenLoc) {
2248 setFunctionHasBranchProtectedScope();
2249
2250 ExprResult CollectionExprResult =
2251 CheckObjCForCollectionOperand(ForLoc, collection);
2252
2253 if (First) {
2254 QualType FirstType;
2255 if (DeclStmt *DS = dyn_cast<DeclStmt>(First)) {
2256 if (!DS->isSingleDecl())
2257 return StmtError(Diag((*DS->decl_begin())->getLocation(),
2258 diag::err_toomany_element_decls));
2259
2260 VarDecl *D = dyn_cast<VarDecl>(DS->getSingleDecl());
2261 if (!D || D->isInvalidDecl())
2262 return StmtError();
2263
2264 FirstType = D->getType();
2265 // C99 6.8.5p3: The declaration part of a 'for' statement shall only
2266 // declare identifiers for objects having storage class 'auto' or
2267 // 'register'.
2268 if (!D->hasLocalStorage())
2269 return StmtError(Diag(D->getLocation(),
2270 diag::err_non_local_variable_decl_in_for));
2271
2272 // If the type contained 'auto', deduce the 'auto' to 'id'.
2273 if (FirstType->getContainedAutoType()) {
2274 OpaqueValueExpr OpaqueId(D->getLocation(), Context.getObjCIdType(),
2275 VK_PRValue);
2276 Expr *DeducedInit = &OpaqueId;
2277 if (DeduceAutoType(D->getTypeSourceInfo(), DeducedInit, FirstType) ==
2278 DAR_Failed)
2279 DiagnoseAutoDeductionFailure(D, DeducedInit);
2280 if (FirstType.isNull()) {
2281 D->setInvalidDecl();
2282 return StmtError();
2283 }
2284
2285 D->setType(FirstType);
2286
2287 if (!inTemplateInstantiation()) {
2288 SourceLocation Loc =
2289 D->getTypeSourceInfo()->getTypeLoc().getBeginLoc();
2290 Diag(Loc, diag::warn_auto_var_is_id)
2291 << D->getDeclName();
2292 }
2293 }
2294
2295 } else {
2296 Expr *FirstE = cast<Expr>(First);
2297 if (!FirstE->isTypeDependent() && !FirstE->isLValue())
2298 return StmtError(
2299 Diag(First->getBeginLoc(), diag::err_selector_element_not_lvalue)
2300 << First->getSourceRange());
2301
2302 FirstType = static_cast<Expr*>(First)->getType();
2303 if (FirstType.isConstQualified())
2304 Diag(ForLoc, diag::err_selector_element_const_type)
2305 << FirstType << First->getSourceRange();
2306 }
2307 if (!FirstType->isDependentType() &&
2308 !FirstType->isObjCObjectPointerType() &&
2309 !FirstType->isBlockPointerType())
2310 return StmtError(Diag(ForLoc, diag::err_selector_element_type)
2311 << FirstType << First->getSourceRange());
2312 }
2313
2314 if (CollectionExprResult.isInvalid())
2315 return StmtError();
2316
2317 CollectionExprResult =
2318 ActOnFinishFullExpr(CollectionExprResult.get(), /*DiscardedValue*/ false);
2319 if (CollectionExprResult.isInvalid())
2320 return StmtError();
2321
2322 return new (Context) ObjCForCollectionStmt(First, CollectionExprResult.get(),
2323 nullptr, ForLoc, RParenLoc);
2324}
2325
2326/// Finish building a variable declaration for a for-range statement.
2327/// \return true if an error occurs.
2328static bool FinishForRangeVarDecl(Sema &SemaRef, VarDecl *Decl, Expr *Init,
2329 SourceLocation Loc, int DiagID) {
2330 if (Decl->getType()->isUndeducedType()) {
2331 ExprResult Res = SemaRef.CorrectDelayedTyposInExpr(Init);
2332 if (!Res.isUsable()) {
2333 Decl->setInvalidDecl();
2334 return true;
2335 }
2336 Init = Res.get();
2337 }
2338
2339 // Deduce the type for the iterator variable now rather than leaving it to
2340 // AddInitializerToDecl, so we can produce a more suitable diagnostic.
2341 QualType InitType;
2342 if ((!isa<InitListExpr>(Init) && Init->getType()->isVoidType()) ||
2343 SemaRef.DeduceAutoType(Decl->getTypeSourceInfo(), Init, InitType) ==
2344 Sema::DAR_Failed)
2345 SemaRef.Diag(Loc, DiagID) << Init->getType();
2346 if (InitType.isNull()) {
2347 Decl->setInvalidDecl();
2348 return true;
2349 }
2350 Decl->setType(InitType);
2351
2352 // In ARC, infer lifetime.
2353 // FIXME: ARC may want to turn this into 'const __unsafe_unretained' if
2354 // we're doing the equivalent of fast iteration.
2355 if (SemaRef.getLangOpts().ObjCAutoRefCount &&
2356 SemaRef.inferObjCARCLifetime(Decl))
2357 Decl->setInvalidDecl();
2358
2359 SemaRef.AddInitializerToDecl(Decl, Init, /*DirectInit=*/false);
2360 SemaRef.FinalizeDeclaration(Decl);
2361 SemaRef.CurContext->addHiddenDecl(Decl);
2362 return false;
2363}
2364
2365namespace {
2366// An enum to represent whether something is dealing with a call to begin()
2367// or a call to end() in a range-based for loop.
2368enum BeginEndFunction {
2369 BEF_begin,
2370 BEF_end
2371};
2372
2373/// Produce a note indicating which begin/end function was implicitly called
2374/// by a C++11 for-range statement. This is often not obvious from the code,
2375/// nor from the diagnostics produced when analysing the implicit expressions
2376/// required in a for-range statement.
2377void NoteForRangeBeginEndFunction(Sema &SemaRef, Expr *E,
2378 BeginEndFunction BEF) {
2379 CallExpr *CE = dyn_cast<CallExpr>(E);
2380 if (!CE)
2381 return;
2382 FunctionDecl *D = dyn_cast<FunctionDecl>(CE->getCalleeDecl());
2383 if (!D)
2384 return;
2385 SourceLocation Loc = D->getLocation();
2386
2387 std::string Description;
2388 bool IsTemplate = false;
2389 if (FunctionTemplateDecl *FunTmpl = D->getPrimaryTemplate()) {
2390 Description = SemaRef.getTemplateArgumentBindingsText(
2391 FunTmpl->getTemplateParameters(), *D->getTemplateSpecializationArgs());
2392 IsTemplate = true;
2393 }
2394
2395 SemaRef.Diag(Loc, diag::note_for_range_begin_end)
2396 << BEF << IsTemplate << Description << E->getType();
2397}
2398
2399/// Build a variable declaration for a for-range statement.
2400VarDecl *BuildForRangeVarDecl(Sema &SemaRef, SourceLocation Loc,
2401 QualType Type, StringRef Name) {
2402 DeclContext *DC = SemaRef.CurContext;
2403 IdentifierInfo *II = &SemaRef.PP.getIdentifierTable().get(Name);
2404 TypeSourceInfo *TInfo = SemaRef.Context.getTrivialTypeSourceInfo(Type, Loc);
2405 VarDecl *Decl = VarDecl::Create(SemaRef.Context, DC, Loc, Loc, II, Type,
2406 TInfo, SC_None);
2407 Decl->setImplicit();
2408 return Decl;
2409}
2410
2411}
2412
2413static bool ObjCEnumerationCollection(Expr *Collection) {
2414 return !Collection->isTypeDependent()
2415 && Collection->getType()->getAs<ObjCObjectPointerType>() != nullptr;
2416}
2417
2418/// ActOnCXXForRangeStmt - Check and build a C++11 for-range statement.
2419///
2420/// C++11 [stmt.ranged]:
2421/// A range-based for statement is equivalent to
2422///
2423/// {
2424/// auto && __range = range-init;
2425/// for ( auto __begin = begin-expr,
2426/// __end = end-expr;
2427/// __begin != __end;
2428/// ++__begin ) {
2429/// for-range-declaration = *__begin;
2430/// statement
2431/// }
2432/// }
2433///
2434/// The body of the loop is not available yet, since it cannot be analysed until
2435/// we have determined the type of the for-range-declaration.
2436StmtResult Sema::ActOnCXXForRangeStmt(Scope *S, SourceLocation ForLoc,
2437 SourceLocation CoawaitLoc, Stmt *InitStmt,
2438 Stmt *First, SourceLocation ColonLoc,
2439 Expr *Range, SourceLocation RParenLoc,
2440 BuildForRangeKind Kind) {
2441 if (!First)
2442 return StmtError();
2443
2444 if (Range && ObjCEnumerationCollection(Range)) {
2445 // FIXME: Support init-statements in Objective-C++20 ranged for statement.
2446 if (InitStmt)
2447 return Diag(InitStmt->getBeginLoc(), diag::err_objc_for_range_init_stmt)
2448 << InitStmt->getSourceRange();
2449 return ActOnObjCForCollectionStmt(ForLoc, First, Range, RParenLoc);
2450 }
2451
2452 DeclStmt *DS = dyn_cast<DeclStmt>(First);
2453 assert(DS && "first part of for range not a decl stmt")(static_cast<void> (0));
2454
2455 if (!DS->isSingleDecl()) {
2456 Diag(DS->getBeginLoc(), diag::err_type_defined_in_for_range);
2457 return StmtError();
2458 }
2459
2460 // This function is responsible for attaching an initializer to LoopVar. We
2461 // must call ActOnInitializerError if we fail to do so.
2462 Decl *LoopVar = DS->getSingleDecl();
2463 if (LoopVar->isInvalidDecl() || !Range ||
2464 DiagnoseUnexpandedParameterPack(Range, UPPC_Expression)) {
2465 ActOnInitializerError(LoopVar);
2466 return StmtError();
2467 }
2468
2469 // Build the coroutine state immediately and not later during template
2470 // instantiation
2471 if (!CoawaitLoc.isInvalid()) {
2472 if (!ActOnCoroutineBodyStart(S, CoawaitLoc, "co_await")) {
2473 ActOnInitializerError(LoopVar);
2474 return StmtError();
2475 }
2476 }
2477
2478 // Build auto && __range = range-init
2479 // Divide by 2, since the variables are in the inner scope (loop body).
2480 const auto DepthStr = std::to_string(S->getDepth() / 2);
2481 SourceLocation RangeLoc = Range->getBeginLoc();
2482 VarDecl *RangeVar = BuildForRangeVarDecl(*this, RangeLoc,
2483 Context.getAutoRRefDeductType(),
2484 std::string("__range") + DepthStr);
2485 if (FinishForRangeVarDecl(*this, RangeVar, Range, RangeLoc,
2486 diag::err_for_range_deduction_failure)) {
2487 ActOnInitializerError(LoopVar);
2488 return StmtError();
2489 }
2490
2491 // Claim the type doesn't contain auto: we've already done the checking.
2492 DeclGroupPtrTy RangeGroup =
2493 BuildDeclaratorGroup(MutableArrayRef<Decl *>((Decl **)&RangeVar, 1));
2494 StmtResult RangeDecl = ActOnDeclStmt(RangeGroup, RangeLoc, RangeLoc);
2495 if (RangeDecl.isInvalid()) {
2496 ActOnInitializerError(LoopVar);
2497 return StmtError();
2498 }
2499
2500 StmtResult R = BuildCXXForRangeStmt(
2501 ForLoc, CoawaitLoc, InitStmt, ColonLoc, RangeDecl.get(),
2502 /*BeginStmt=*/nullptr, /*EndStmt=*/nullptr,
2503 /*Cond=*/nullptr, /*Inc=*/nullptr, DS, RParenLoc, Kind);
2504 if (R.isInvalid()) {
2505 ActOnInitializerError(LoopVar);
2506 return StmtError();
2507 }
2508
2509 return R;
2510}
2511
2512/// Create the initialization, compare, and increment steps for
2513/// the range-based for loop expression.
2514/// This function does not handle array-based for loops,
2515/// which are created in Sema::BuildCXXForRangeStmt.
2516///
2517/// \returns a ForRangeStatus indicating success or what kind of error occurred.
2518/// BeginExpr and EndExpr are set and FRS_Success is returned on success;
2519/// CandidateSet and BEF are set and some non-success value is returned on
2520/// failure.
2521static Sema::ForRangeStatus
2522BuildNonArrayForRange(Sema &SemaRef, Expr *BeginRange, Expr *EndRange,
2523 QualType RangeType, VarDecl *BeginVar, VarDecl *EndVar,
2524 SourceLocation ColonLoc, SourceLocation CoawaitLoc,
2525 OverloadCandidateSet *CandidateSet, ExprResult *BeginExpr,
2526 ExprResult *EndExpr, BeginEndFunction *BEF) {
2527 DeclarationNameInfo BeginNameInfo(
2528 &SemaRef.PP.getIdentifierTable().get("begin"), ColonLoc);
2529 DeclarationNameInfo EndNameInfo(&SemaRef.PP.getIdentifierTable().get("end"),
2530 ColonLoc);
2531
2532 LookupResult BeginMemberLookup(SemaRef, BeginNameInfo,
2533 Sema::LookupMemberName);
2534 LookupResult EndMemberLookup(SemaRef, EndNameInfo, Sema::LookupMemberName);
2535
2536 auto BuildBegin = [&] {
2537 *BEF = BEF_begin;
2538 Sema::ForRangeStatus RangeStatus =
2539 SemaRef.BuildForRangeBeginEndCall(ColonLoc, ColonLoc, BeginNameInfo,
2540 BeginMemberLookup, CandidateSet,
2541 BeginRange, BeginExpr);
2542
2543 if (RangeStatus != Sema::FRS_Success) {
2544 if (RangeStatus == Sema::FRS_DiagnosticIssued)
2545 SemaRef.Diag(BeginRange->getBeginLoc(), diag::note_in_for_range)
2546 << ColonLoc << BEF_begin << BeginRange->getType();
2547 return RangeStatus;
2548 }
2549 if (!CoawaitLoc.isInvalid()) {
2550 // FIXME: getCurScope() should not be used during template instantiation.
2551 // We should pick up the set of unqualified lookup results for operator
2552 // co_await during the initial parse.
2553 *BeginExpr = SemaRef.ActOnCoawaitExpr(SemaRef.getCurScope(), ColonLoc,
2554 BeginExpr->get());
2555 if (BeginExpr->isInvalid())
2556 return Sema::FRS_DiagnosticIssued;
2557 }
2558 if (FinishForRangeVarDecl(SemaRef, BeginVar, BeginExpr->get(), ColonLoc,
2559 diag::err_for_range_iter_deduction_failure)) {
2560 NoteForRangeBeginEndFunction(SemaRef, BeginExpr->get(), *BEF);
2561 return Sema::FRS_DiagnosticIssued;
2562 }
2563 return Sema::FRS_Success;
2564 };
2565
2566 auto BuildEnd = [&] {
2567 *BEF = BEF_end;
2568 Sema::ForRangeStatus RangeStatus =
2569 SemaRef.BuildForRangeBeginEndCall(ColonLoc, ColonLoc, EndNameInfo,
2570 EndMemberLookup, CandidateSet,
2571 EndRange, EndExpr);
2572 if (RangeStatus != Sema::FRS_Success) {
2573 if (RangeStatus == Sema::FRS_DiagnosticIssued)
2574 SemaRef.Diag(EndRange->getBeginLoc(), diag::note_in_for_range)
2575 << ColonLoc << BEF_end << EndRange->getType();
2576 return RangeStatus;
2577 }
2578 if (FinishForRangeVarDecl(SemaRef, EndVar, EndExpr->get(), ColonLoc,
2579 diag::err_for_range_iter_deduction_failure)) {
2580 NoteForRangeBeginEndFunction(SemaRef, EndExpr->get(), *BEF);
2581 return Sema::FRS_DiagnosticIssued;
2582 }
2583 return Sema::FRS_Success;
2584 };
2585
2586 if (CXXRecordDecl *D = RangeType->getAsCXXRecordDecl()) {
2587 // - if _RangeT is a class type, the unqualified-ids begin and end are
2588 // looked up in the scope of class _RangeT as if by class member access
2589 // lookup (3.4.5), and if either (or both) finds at least one
2590 // declaration, begin-expr and end-expr are __range.begin() and
2591 // __range.end(), respectively;
2592 SemaRef.LookupQualifiedName(BeginMemberLookup, D);
2593 if (BeginMemberLookup.isAmbiguous())
2594 return Sema::FRS_DiagnosticIssued;
2595
2596 SemaRef.LookupQualifiedName(EndMemberLookup, D);
2597 if (EndMemberLookup.isAmbiguous())
2598 return Sema::FRS_DiagnosticIssued;
2599
2600 if (BeginMemberLookup.empty() != EndMemberLookup.empty()) {
2601 // Look up the non-member form of the member we didn't find, first.
2602 // This way we prefer a "no viable 'end'" diagnostic over a "i found
2603 // a 'begin' but ignored it because there was no member 'end'"
2604 // diagnostic.
2605 auto BuildNonmember = [&](
2606 BeginEndFunction BEFFound, LookupResult &Found,
2607 llvm::function_ref<Sema::ForRangeStatus()> BuildFound,
2608 llvm::function_ref<Sema::ForRangeStatus()> BuildNotFound) {
2609 LookupResult OldFound = std::move(Found);
2610 Found.clear();
2611
2612 if (Sema::ForRangeStatus Result = BuildNotFound())
2613 return Result;
2614
2615 switch (BuildFound()) {
2616 case Sema::FRS_Success:
2617 return Sema::FRS_Success;
2618
2619 case Sema::FRS_NoViableFunction:
2620 CandidateSet->NoteCandidates(
2621 PartialDiagnosticAt(BeginRange->getBeginLoc(),
2622 SemaRef.PDiag(diag::err_for_range_invalid)
2623 << BeginRange->getType() << BEFFound),
2624 SemaRef, OCD_AllCandidates, BeginRange);
2625 LLVM_FALLTHROUGH[[gnu::fallthrough]];
2626
2627 case Sema::FRS_DiagnosticIssued:
2628 for (NamedDecl *D : OldFound) {
2629 SemaRef.Diag(D->getLocation(),
2630 diag::note_for_range_member_begin_end_ignored)
2631 << BeginRange->getType() << BEFFound;
2632 }
2633 return Sema::FRS_DiagnosticIssued;
2634 }
2635 llvm_unreachable("unexpected ForRangeStatus")__builtin_unreachable();
2636 };
2637 if (BeginMemberLookup.empty())
2638 return BuildNonmember(BEF_end, EndMemberLookup, BuildEnd, BuildBegin);
2639 return BuildNonmember(BEF_begin, BeginMemberLookup, BuildBegin, BuildEnd);
2640 }
2641 } else {
2642 // - otherwise, begin-expr and end-expr are begin(__range) and
2643 // end(__range), respectively, where begin and end are looked up with
2644 // argument-dependent lookup (3.4.2). For the purposes of this name
2645 // lookup, namespace std is an associated namespace.
2646 }
2647
2648 if (Sema::ForRangeStatus Result = BuildBegin())
2649 return Result;
2650 return BuildEnd();
2651}
2652
2653/// Speculatively attempt to dereference an invalid range expression.
2654/// If the attempt fails, this function will return a valid, null StmtResult
2655/// and emit no diagnostics.
2656static StmtResult RebuildForRangeWithDereference(Sema &SemaRef, Scope *S,
2657 SourceLocation ForLoc,
2658 SourceLocation CoawaitLoc,
2659 Stmt *InitStmt,
2660 Stmt *LoopVarDecl,
2661 SourceLocation ColonLoc,
2662 Expr *Range,
2663 SourceLocation RangeLoc,
2664 SourceLocation RParenLoc) {
2665 // Determine whether we can rebuild the for-range statement with a
2666 // dereferenced range expression.
2667 ExprResult AdjustedRange;
2668 {
2669 Sema::SFINAETrap Trap(SemaRef);
2670
2671 AdjustedRange = SemaRef.BuildUnaryOp(S, RangeLoc, UO_Deref, Range);
2672 if (AdjustedRange.isInvalid())
2673 return StmtResult();
2674
2675 StmtResult SR = SemaRef.ActOnCXXForRangeStmt(
2676 S, ForLoc, CoawaitLoc, InitStmt, LoopVarDecl, ColonLoc,
2677 AdjustedRange.get(), RParenLoc, Sema::BFRK_Check);
2678 if (SR.isInvalid())
2679 return StmtResult();
2680 }
2681
2682 // The attempt to dereference worked well enough that it could produce a valid
2683 // loop. Produce a fixit, and rebuild the loop with diagnostics enabled, in
2684 // case there are any other (non-fatal) problems with it.
2685 SemaRef.Diag(RangeLoc, diag::err_for_range_dereference)
2686 << Range->getType() << FixItHint::CreateInsertion(RangeLoc, "*");
2687 return SemaRef.ActOnCXXForRangeStmt(
2688 S, ForLoc, CoawaitLoc, InitStmt, LoopVarDecl, ColonLoc,
2689 AdjustedRange.get(), RParenLoc, Sema::BFRK_Rebuild);
2690}
2691
2692/// BuildCXXForRangeStmt - Build or instantiate a C++11 for-range statement.
2693StmtResult Sema::BuildCXXForRangeStmt(SourceLocation ForLoc,
2694 SourceLocation CoawaitLoc, Stmt *InitStmt,
2695 SourceLocation ColonLoc, Stmt *RangeDecl,
2696 Stmt *Begin, Stmt *End, Expr *Cond,
2697 Expr *Inc, Stmt *LoopVarDecl,
2698 SourceLocation RParenLoc,
2699 BuildForRangeKind Kind) {
2700 // FIXME: This should not be used during template instantiation. We should
2701 // pick up the set of unqualified lookup results for the != and + operators
2702 // in the initial parse.
2703 //
2704 // Testcase (accepts-invalid):
2705 // template<typename T> void f() { for (auto x : T()) {} }
2706 // namespace N { struct X { X begin(); X end(); int operator*(); }; }
2707 // bool operator!=(N::X, N::X); void operator++(N::X);
2708 // void g() { f<N::X>(); }
2709 Scope *S = getCurScope();
2710
2711 DeclStmt *RangeDS = cast<DeclStmt>(RangeDecl);
2712 VarDecl *RangeVar = cast<VarDecl>(RangeDS->getSingleDecl());
2713 QualType RangeVarType = RangeVar->getType();
2714
2715 DeclStmt *LoopVarDS = cast<DeclStmt>(LoopVarDecl);
2716 VarDecl *LoopVar = cast<VarDecl>(LoopVarDS->getSingleDecl());
2717
2718 StmtResult BeginDeclStmt = Begin;
2719 StmtResult EndDeclStmt = End;
2720 ExprResult NotEqExpr = Cond, IncrExpr = Inc;
2721
2722 if (RangeVarType->isDependentType()) {
2723 // The range is implicitly used as a placeholder when it is dependent.
2724 RangeVar->markUsed(Context);
2725
2726 // Deduce any 'auto's in the loop variable as 'DependentTy'. We'll fill
2727 // them in properly when we instantiate the loop.
2728 if (!LoopVar->isInvalidDecl() && Kind != BFRK_Check) {
2729 if (auto *DD = dyn_cast<DecompositionDecl>(LoopVar))
2730 for (auto *Binding : DD->bindings())
2731 Binding->setType(Context.DependentTy);
2732 LoopVar->setType(SubstAutoType(LoopVar->getType(), Context.DependentTy));
2733 }
2734 } else if (!BeginDeclStmt.get()) {
2735 SourceLocation RangeLoc = RangeVar->getLocation();
2736
2737 const QualType RangeVarNonRefType = RangeVarType.getNonReferenceType();
2738
2739 ExprResult BeginRangeRef = BuildDeclRefExpr(RangeVar, RangeVarNonRefType,
2740 VK_LValue, ColonLoc);
2741 if (BeginRangeRef.isInvalid())
2742 return StmtError();
2743
2744 ExprResult EndRangeRef = BuildDeclRefExpr(RangeVar, RangeVarNonRefType,
2745 VK_LValue, ColonLoc);
2746 if (EndRangeRef.isInvalid())
2747 return StmtError();
2748
2749 QualType AutoType = Context.getAutoDeductType();
2750 Expr *Range = RangeVar->getInit();
2751 if (!Range)
2752 return StmtError();
2753 QualType RangeType = Range->getType();
2754
2755 if (RequireCompleteType(RangeLoc, RangeType,
2756 diag::err_for_range_incomplete_type))
2757 return StmtError();
2758
2759 // Build auto __begin = begin-expr, __end = end-expr.
2760 // Divide by 2, since the variables are in the inner scope (loop body).
2761 const auto DepthStr = std::to_string(S->getDepth() / 2);
2762 VarDecl *BeginVar = BuildForRangeVarDecl(*this, ColonLoc, AutoType,
2763 std::string("__begin") + DepthStr);
2764 VarDecl *EndVar = BuildForRangeVarDecl(*this, ColonLoc, AutoType,
2765 std::string("__end") + DepthStr);
2766
2767 // Build begin-expr and end-expr and attach to __begin and __end variables.
2768 ExprResult BeginExpr, EndExpr;
2769 if (const ArrayType *UnqAT = RangeType->getAsArrayTypeUnsafe()) {
2770 // - if _RangeT is an array type, begin-expr and end-expr are __range and
2771 // __range + __bound, respectively, where __bound is the array bound. If
2772 // _RangeT is an array of unknown size or an array of incomplete type,
2773 // the program is ill-formed;
2774
2775 // begin-expr is __range.
2776 BeginExpr = BeginRangeRef;
2777 if (!CoawaitLoc.isInvalid()) {
2778 BeginExpr = ActOnCoawaitExpr(S, ColonLoc, BeginExpr.get());
2779 if (BeginExpr.isInvalid())
2780 return StmtError();
2781 }
2782 if (FinishForRangeVarDecl(*this, BeginVar, BeginRangeRef.get(), ColonLoc,
2783 diag::err_for_range_iter_deduction_failure)) {
2784 NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin);
2785 return StmtError();
2786 }
2787
2788 // Find the array bound.
2789 ExprResult BoundExpr;
2790 if (const ConstantArrayType *CAT = dyn_cast<ConstantArrayType>(UnqAT))
2791 BoundExpr = IntegerLiteral::Create(
2792 Context, CAT->getSize(), Context.getPointerDiffType(), RangeLoc);
2793 else if (const VariableArrayType *VAT =
2794 dyn_cast<VariableArrayType>(UnqAT)) {
2795 // For a variably modified type we can't just use the expression within
2796 // the array bounds, since we don't want that to be re-evaluated here.
2797 // Rather, we need to determine what it was when the array was first
2798 // created - so we resort to using sizeof(vla)/sizeof(element).
2799 // For e.g.
2800 // void f(int b) {
2801 // int vla[b];
2802 // b = -1; <-- This should not affect the num of iterations below
2803 // for (int &c : vla) { .. }
2804 // }
2805
2806 // FIXME: This results in codegen generating IR that recalculates the
2807 // run-time number of elements (as opposed to just using the IR Value
2808 // that corresponds to the run-time value of each bound that was
2809 // generated when the array was created.) If this proves too embarrassing
2810 // even for unoptimized IR, consider passing a magic-value/cookie to
2811 // codegen that then knows to simply use that initial llvm::Value (that
2812 // corresponds to the bound at time of array creation) within
2813 // getelementptr. But be prepared to pay the price of increasing a
2814 // customized form of coupling between the two components - which could
2815 // be hard to maintain as the codebase evolves.
2816
2817 ExprResult SizeOfVLAExprR = ActOnUnaryExprOrTypeTraitExpr(
2818 EndVar->getLocation(), UETT_SizeOf,
2819 /*IsType=*/true,
2820 CreateParsedType(VAT->desugar(), Context.getTrivialTypeSourceInfo(
2821 VAT->desugar(), RangeLoc))
2822 .getAsOpaquePtr(),
2823 EndVar->getSourceRange());
2824 if (SizeOfVLAExprR.isInvalid())
2825 return StmtError();
2826
2827 ExprResult SizeOfEachElementExprR = ActOnUnaryExprOrTypeTraitExpr(
2828 EndVar->getLocation(), UETT_SizeOf,
2829 /*IsType=*/true,
2830 CreateParsedType(VAT->desugar(),
2831 Context.getTrivialTypeSourceInfo(
2832 VAT->getElementType(), RangeLoc))
2833 .getAsOpaquePtr(),
2834 EndVar->getSourceRange());
2835 if (SizeOfEachElementExprR.isInvalid())
2836 return StmtError();
2837
2838 BoundExpr =
2839 ActOnBinOp(S, EndVar->getLocation(), tok::slash,
2840 SizeOfVLAExprR.get(), SizeOfEachElementExprR.get());
2841 if (BoundExpr.isInvalid())
2842 return StmtError();
2843
2844 } else {
2845 // Can't be a DependentSizedArrayType or an IncompleteArrayType since
2846 // UnqAT is not incomplete and Range is not type-dependent.
2847 llvm_unreachable("Unexpected array type in for-range")__builtin_unreachable();
2848 }
2849
2850 // end-expr is __range + __bound.
2851 EndExpr = ActOnBinOp(S, ColonLoc, tok::plus, EndRangeRef.get(),
2852 BoundExpr.get());
2853 if (EndExpr.isInvalid())
2854 return StmtError();
2855 if (FinishForRangeVarDecl(*this, EndVar, EndExpr.get(), ColonLoc,
2856 diag::err_for_range_iter_deduction_failure)) {
2857 NoteForRangeBeginEndFunction(*this, EndExpr.get(), BEF_end);
2858 return StmtError();
2859 }
2860 } else {
2861 OverloadCandidateSet CandidateSet(RangeLoc,
2862 OverloadCandidateSet::CSK_Normal);
2863 BeginEndFunction BEFFailure;
2864 ForRangeStatus RangeStatus = BuildNonArrayForRange(
2865 *this, BeginRangeRef.get(), EndRangeRef.get(), RangeType, BeginVar,
2866 EndVar, ColonLoc, CoawaitLoc, &CandidateSet, &BeginExpr, &EndExpr,
2867 &BEFFailure);
2868
2869 if (Kind == BFRK_Build && RangeStatus == FRS_NoViableFunction &&
2870 BEFFailure == BEF_begin) {
2871 // If the range is being built from an array parameter, emit a
2872 // a diagnostic that it is being treated as a pointer.
2873 if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(Range)) {
2874 if (ParmVarDecl *PVD = dyn_cast<ParmVarDecl>(DRE->getDecl())) {
2875 QualType ArrayTy = PVD->getOriginalType();
2876 QualType PointerTy = PVD->getType();
2877 if (PointerTy->isPointerType() && ArrayTy->isArrayType()) {
2878 Diag(Range->getBeginLoc(), diag::err_range_on_array_parameter)
2879 << RangeLoc << PVD << ArrayTy << PointerTy;
2880 Diag(PVD->getLocation(), diag::note_declared_at);
2881 return StmtError();
2882 }
2883 }
2884 }
2885
2886 // If building the range failed, try dereferencing the range expression
2887 // unless a diagnostic was issued or the end function is problematic.
2888 StmtResult SR = RebuildForRangeWithDereference(*this, S, ForLoc,
2889 CoawaitLoc, InitStmt,
2890 LoopVarDecl, ColonLoc,
2891 Range, RangeLoc,
2892 RParenLoc);
2893 if (SR.isInvalid() || SR.isUsable())
2894 return SR;
2895 }
2896
2897 // Otherwise, emit diagnostics if we haven't already.
2898 if (RangeStatus == FRS_NoViableFunction) {
2899 Expr *Range = BEFFailure ? EndRangeRef.get() : BeginRangeRef.get();
2900 CandidateSet.NoteCandidates(
2901 PartialDiagnosticAt(Range->getBeginLoc(),
2902 PDiag(diag::err_for_range_invalid)
2903 << RangeLoc << Range->getType()
2904 << BEFFailure),
2905 *this, OCD_AllCandidates, Range);
2906 }
2907 // Return an error if no fix was discovered.
2908 if (RangeStatus != FRS_Success)
2909 return StmtError();
2910 }
2911
2912 assert(!BeginExpr.isInvalid() && !EndExpr.isInvalid() &&(static_cast<void> (0))
2913 "invalid range expression in for loop")(static_cast<void> (0));
2914
2915 // C++11 [dcl.spec.auto]p7: BeginType and EndType must be the same.
2916 // C++1z removes this restriction.
2917 QualType BeginType = BeginVar->getType(), EndType = EndVar->getType();
2918 if (!Context.hasSameType(BeginType, EndType)) {
2919 Diag(RangeLoc, getLangOpts().CPlusPlus17
2920 ? diag::warn_for_range_begin_end_types_differ
2921 : diag::ext_for_range_begin_end_types_differ)
2922 << BeginType << EndType;
2923 NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin);
2924 NoteForRangeBeginEndFunction(*this, EndExpr.get(), BEF_end);
2925 }
2926
2927 BeginDeclStmt =
2928 ActOnDeclStmt(ConvertDeclToDeclGroup(BeginVar), ColonLoc, ColonLoc);
2929 EndDeclStmt =
2930 ActOnDeclStmt(ConvertDeclToDeclGroup(EndVar), ColonLoc, ColonLoc);
2931
2932 const QualType BeginRefNonRefType = BeginType.getNonReferenceType();
2933 ExprResult BeginRef = BuildDeclRefExpr(BeginVar, BeginRefNonRefType,
2934 VK_LValue, ColonLoc);
2935 if (BeginRef.isInvalid())
2936 return StmtError();
2937
2938 ExprResult EndRef = BuildDeclRefExpr(EndVar, EndType.getNonReferenceType(),
2939 VK_LValue, ColonLoc);
2940 if (EndRef.isInvalid())
2941 return StmtError();
2942
2943 // Build and check __begin != __end expression.
2944 NotEqExpr = ActOnBinOp(S, ColonLoc, tok::exclaimequal,
2945 BeginRef.get(), EndRef.get());
2946 if (!NotEqExpr.isInvalid())
2947 NotEqExpr = CheckBooleanCondition(ColonLoc, NotEqExpr.get());
2948 if (!NotEqExpr.isInvalid())
2949 NotEqExpr =
2950 ActOnFinishFullExpr(NotEqExpr.get(), /*DiscardedValue*/ false);
2951 if (NotEqExpr.isInvalid()) {
2952 Diag(RangeLoc, diag::note_for_range_invalid_iterator)
2953 << RangeLoc << 0 << BeginRangeRef.get()->getType();
2954 NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin);
2955 if (!Context.hasSameType(BeginType, EndType))
2956 NoteForRangeBeginEndFunction(*this, EndExpr.get(), BEF_end);
2957 return StmtError();
2958 }
2959
2960 // Build and check ++__begin expression.
2961 BeginRef = BuildDeclRefExpr(BeginVar, BeginRefNonRefType,
2962 VK_LValue, ColonLoc);
2963 if (BeginRef.isInvalid())
2964 return StmtError();
2965
2966 IncrExpr = ActOnUnaryOp(S, ColonLoc, tok::plusplus, BeginRef.get());
2967 if (!IncrExpr.isInvalid() && CoawaitLoc.isValid())
2968 // FIXME: getCurScope() should not be used during template instantiation.
2969 // We should pick up the set of unqualified lookup results for operator
2970 // co_await during the initial parse.
2971 IncrExpr = ActOnCoawaitExpr(S, CoawaitLoc, IncrExpr.get());
2972 if (!IncrExpr.isInvalid())
2973 IncrExpr = ActOnFinishFullExpr(IncrExpr.get(), /*DiscardedValue*/ false);
2974 if (IncrExpr.isInvalid()) {
2975 Diag(RangeLoc, diag::note_for_range_invalid_iterator)
2976 << RangeLoc << 2 << BeginRangeRef.get()->getType() ;
2977 NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin);
2978 return StmtError();
2979 }
2980
2981 // Build and check *__begin expression.
2982 BeginRef = BuildDeclRefExpr(BeginVar, BeginRefNonRefType,
2983 VK_LValue, ColonLoc);
2984 if (BeginRef.isInvalid())
2985 return StmtError();
2986
2987 ExprResult DerefExpr = ActOnUnaryOp(S, ColonLoc, tok::star, BeginRef.get());
2988 if (DerefExpr.isInvalid()) {
2989 Diag(RangeLoc, diag::note_for_range_invalid_iterator)
2990 << RangeLoc << 1 << BeginRangeRef.get()->getType();
2991 NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin);
2992 return StmtError();
2993 }
2994
2995 // Attach *__begin as initializer for VD. Don't touch it if we're just
2996 // trying to determine whether this would be a valid range.
2997 if (!LoopVar->isInvalidDecl() && Kind != BFRK_Check) {
2998 AddInitializerToDecl(LoopVar, DerefExpr.get(), /*DirectInit=*/false);
2999 if (LoopVar->isInvalidDecl() ||
3000 (LoopVar->getInit() && LoopVar->getInit()->containsErrors()))
3001 NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin);
3002 }
3003 }
3004
3005 // Don't bother to actually allocate the result if we're just trying to
3006 // determine whether it would be valid.
3007 if (Kind == BFRK_Check)
3008 return StmtResult();
3009
3010 // In OpenMP loop region loop control variable must be private. Perform
3011 // analysis of first part (if any).
3012 if (getLangOpts().OpenMP >= 50 && BeginDeclStmt.isUsable())
3013 ActOnOpenMPLoopInitialization(ForLoc, BeginDeclStmt.get());
3014
3015 return new (Context) CXXForRangeStmt(
3016 InitStmt, RangeDS, cast_or_null<DeclStmt>(BeginDeclStmt.get()),
3017 cast_or_null<DeclStmt>(EndDeclStmt.get()), NotEqExpr.get(),
3018 IncrExpr.get(), LoopVarDS, /*Body=*/nullptr, ForLoc, CoawaitLoc,
3019 ColonLoc, RParenLoc);
3020}
3021
3022/// FinishObjCForCollectionStmt - Attach the body to a objective-C foreach
3023/// statement.
3024StmtResult Sema::FinishObjCForCollectionStmt(Stmt *S, Stmt *B) {
3025 if (!S || !B)
3026 return StmtError();
3027 ObjCForCollectionStmt * ForStmt = cast<ObjCForCollectionStmt>(S);
3028
3029 ForStmt->setBody(B);
3030 return S;
3031}
3032
3033// Warn when the loop variable is a const reference that creates a copy.
3034// Suggest using the non-reference type for copies. If a copy can be prevented
3035// suggest the const reference type that would do so.
3036// For instance, given "for (const &Foo : Range)", suggest
3037// "for (const Foo : Range)" to denote a copy is made for the loop. If
3038// possible, also suggest "for (const &Bar : Range)" if this type prevents
3039// the copy altogether.
3040static void DiagnoseForRangeReferenceVariableCopies(Sema &SemaRef,
3041 const VarDecl *VD,
3042 QualType RangeInitType) {
3043 const Expr *InitExpr = VD->getInit();
3044 if (!InitExpr)
3045 return;
3046
3047 QualType VariableType = VD->getType();
3048
3049 if (auto Cleanups = dyn_cast<ExprWithCleanups>(InitExpr))
3050 if (!Cleanups->cleanupsHaveSideEffects())
3051 InitExpr = Cleanups->getSubExpr();
3052
3053 const MaterializeTemporaryExpr *MTE =
3054 dyn_cast<MaterializeTemporaryExpr>(InitExpr);
3055
3056 // No copy made.
3057 if (!MTE)
3058 return;
3059
3060 const Expr *E = MTE->getSubExpr()->IgnoreImpCasts();
3061
3062 // Searching for either UnaryOperator for dereference of a pointer or
3063 // CXXOperatorCallExpr for handling iterators.
3064 while (!isa<CXXOperatorCallExpr>(E) && !isa<UnaryOperator>(E)) {
3065 if (const CXXConstructExpr *CCE = dyn_cast<CXXConstructExpr>(E)) {
3066 E = CCE->getArg(0);
3067 } else if (const CXXMemberCallExpr *Call = dyn_cast<CXXMemberCallExpr>(E)) {
3068 const MemberExpr *ME = cast<MemberExpr>(Call->getCallee());
3069 E = ME->getBase();
3070 } else {
3071 const MaterializeTemporaryExpr *MTE = cast<MaterializeTemporaryExpr>(E);
3072 E = MTE->getSubExpr();
3073 }
3074 E = E->IgnoreImpCasts();
3075 }
3076
3077 QualType ReferenceReturnType;
3078 if (isa<UnaryOperator>(E)) {
3079 ReferenceReturnType = SemaRef.Context.getLValueReferenceType(E->getType());
3080 } else {
3081 const CXXOperatorCallExpr *Call = cast<CXXOperatorCallExpr>(E);
3082 const FunctionDecl *FD = Call->getDirectCallee();
3083 QualType ReturnType = FD->getReturnType();
3084 if (ReturnType->isReferenceType())
3085 ReferenceReturnType = ReturnType;
3086 }
3087
3088 if (!ReferenceReturnType.isNull()) {
3089 // Loop variable creates a temporary. Suggest either to go with
3090 // non-reference loop variable to indicate a copy is made, or
3091 // the correct type to bind a const reference.
3092 SemaRef.Diag(VD->getLocation(),
3093 diag::warn_for_range_const_ref_binds_temp_built_from_ref)
3094 << VD << VariableType << ReferenceReturnType;
3095 QualType NonReferenceType = VariableType.getNonReferenceType();
3096 NonReferenceType.removeLocalConst();
3097 QualType NewReferenceType =
3098 SemaRef.Context.getLValueReferenceType(E->getType().withConst());
3099 SemaRef.Diag(VD->getBeginLoc(), diag::note_use_type_or_non_reference)
3100 << NonReferenceType << NewReferenceType << VD->getSourceRange()
3101 << FixItHint::CreateRemoval(VD->getTypeSpecEndLoc());
3102 } else if (!VariableType->isRValueReferenceType()) {
3103 // The range always returns a copy, so a temporary is always created.
3104 // Suggest removing the reference from the loop variable.
3105 // If the type is a rvalue reference do not warn since that changes the
3106 // semantic of the code.
3107 SemaRef.Diag(VD->getLocation(), diag::warn_for_range_ref_binds_ret_temp)
3108 << VD << RangeInitType;
3109 QualType NonReferenceType = VariableType.getNonReferenceType();
3110 NonReferenceType.removeLocalConst();
3111 SemaRef.Diag(VD->getBeginLoc(), diag::note_use_non_reference_type)
3112 << NonReferenceType << VD->getSourceRange()
3113 << FixItHint::CreateRemoval(VD->getTypeSpecEndLoc());
3114 }
3115}
3116
3117/// Determines whether the @p VariableType's declaration is a record with the
3118/// clang::trivial_abi attribute.
3119static bool hasTrivialABIAttr(QualType VariableType) {
3120 if (CXXRecordDecl *RD = VariableType->getAsCXXRecordDecl())
3121 return RD->hasAttr<TrivialABIAttr>();
3122
3123 return false;
3124}
3125
3126// Warns when the loop variable can be changed to a reference type to
3127// prevent a copy. For instance, if given "for (const Foo x : Range)" suggest
3128// "for (const Foo &x : Range)" if this form does not make a copy.
3129static void DiagnoseForRangeConstVariableCopies(Sema &SemaRef,
3130 const VarDecl *VD) {
3131 const Expr *InitExpr = VD->getInit();
3132 if (!InitExpr)
3133 return;
3134
3135 QualType VariableType = VD->getType();
3136
3137 if (const CXXConstructExpr *CE = dyn_cast<CXXConstructExpr>(InitExpr)) {
3138 if (!CE->getConstructor()->isCopyConstructor())
3139 return;
3140 } else if (const CastExpr *CE = dyn_cast<CastExpr>(InitExpr)) {
3141 if (CE->getCastKind() != CK_LValueToRValue)
3142 return;
3143 } else {
3144 return;
3145 }
3146
3147 // Small trivially copyable types are cheap to copy. Do not emit the
3148 // diagnostic for these instances. 64 bytes is a common size of a cache line.
3149 // (The function `getTypeSize` returns the size in bits.)
3150 ASTContext &Ctx = SemaRef.Context;
3151 if (Ctx.getTypeSize(VariableType) <= 64 * 8 &&
3152 (VariableType.isTriviallyCopyableType(Ctx) ||
3153 hasTrivialABIAttr(VariableType)))
3154 return;
3155
3156 // Suggest changing from a const variable to a const reference variable
3157 // if doing so will prevent a copy.
3158 SemaRef.Diag(VD->getLocation(), diag::warn_for_range_copy)
3159 << VD << VariableType;
3160 SemaRef.Diag(VD->getBeginLoc(), diag::note_use_reference_type)
3161 << SemaRef.Context.getLValueReferenceType(VariableType)
3162 << VD->getSourceRange()
3163 << FixItHint::CreateInsertion(VD->getLocation(), "&");
3164}
3165
3166/// DiagnoseForRangeVariableCopies - Diagnose three cases and fixes for them.
3167/// 1) for (const foo &x : foos) where foos only returns a copy. Suggest
3168/// using "const foo x" to show that a copy is made
3169/// 2) for (const bar &x : foos) where bar is a temporary initialized by bar.
3170/// Suggest either "const bar x" to keep the copying or "const foo& x" to
3171/// prevent the copy.
3172/// 3) for (const foo x : foos) where x is constructed from a reference foo.
3173/// Suggest "const foo &x" to prevent the copy.
3174static void DiagnoseForRangeVariableCopies(Sema &SemaRef,
3175 const CXXForRangeStmt *ForStmt) {
3176 if (SemaRef.inTemplateInstantiation())
3177 return;
3178
3179 if (SemaRef.Diags.isIgnored(
3180 diag::warn_for_range_const_ref_binds_temp_built_from_ref,
3181 ForStmt->getBeginLoc()) &&
3182 SemaRef.Diags.isIgnored(diag::warn_for_range_ref_binds_ret_temp,
3183 ForStmt->getBeginLoc()) &&
3184 SemaRef.Diags.isIgnored(diag::warn_for_range_copy,
3185 ForStmt->getBeginLoc())) {
3186 return;
3187 }
3188
3189 const VarDecl *VD = ForStmt->getLoopVariable();
3190 if (!VD)
3191 return;
3192
3193 QualType VariableType = VD->getType();
3194
3195 if (VariableType->isIncompleteType())
3196 return;
3197
3198 const Expr *InitExpr = VD->getInit();
3199 if (!InitExpr)
3200 return;
3201
3202 if (InitExpr->getExprLoc().isMacroID())
3203 return;
3204
3205 if (VariableType->isReferenceType()) {
3206 DiagnoseForRangeReferenceVariableCopies(SemaRef, VD,
3207 ForStmt->getRangeInit()->getType());
3208 } else if (VariableType.isConstQualified()) {
3209 DiagnoseForRangeConstVariableCopies(SemaRef, VD);
3210 }
3211}
3212
3213/// FinishCXXForRangeStmt - Attach the body to a C++0x for-range statement.
3214/// This is a separate step from ActOnCXXForRangeStmt because analysis of the
3215/// body cannot be performed until after the type of the range variable is
3216/// determined.
3217StmtResult Sema::FinishCXXForRangeStmt(Stmt *S, Stmt *B) {
3218 if (!S || !B)
3219 return StmtError();
3220
3221 if (isa<ObjCForCollectionStmt>(S))
3222 return FinishObjCForCollectionStmt(S, B);
3223
3224 CXXForRangeStmt *ForStmt = cast<CXXForRangeStmt>(S);
3225 ForStmt->setBody(B);
3226
3227 DiagnoseEmptyStmtBody(ForStmt->getRParenLoc(), B,
3228 diag::warn_empty_range_based_for_body);
3229
3230 DiagnoseForRangeVariableCopies(*this, ForStmt);
3231
3232 return S;
3233}
3234
3235StmtResult Sema::ActOnGotoStmt(SourceLocation GotoLoc,
3236 SourceLocation LabelLoc,
3237 LabelDecl *TheDecl) {
3238 setFunctionHasBranchIntoScope();
3239 TheDecl->markUsed(Context);
3240 return new (Context) GotoStmt(TheDecl, GotoLoc, LabelLoc);
3241}
3242
3243StmtResult
3244Sema::ActOnIndirectGotoStmt(SourceLocation GotoLoc, SourceLocation StarLoc,
3245 Expr *E) {
3246 // Convert operand to void*
3247 if (!E->isTypeDependent()) {
3248 QualType ETy = E->getType();
3249 QualType DestTy = Context.getPointerType(Context.VoidTy.withConst());
3250 ExprResult ExprRes = E;
3251 AssignConvertType ConvTy =
3252 CheckSingleAssignmentConstraints(DestTy, ExprRes);
3253 if (ExprRes.isInvalid())
3254 return StmtError();
3255 E = ExprRes.get();
3256 if (DiagnoseAssignmentResult(ConvTy, StarLoc, DestTy, ETy, E, AA_Passing))
3257 return StmtError();
3258 }
3259
3260 ExprResult ExprRes = ActOnFinishFullExpr(E, /*DiscardedValue*/ false);
3261 if (ExprRes.isInvalid())
3262 return StmtError();
3263 E = ExprRes.get();
3264
3265 setFunctionHasIndirectGoto();
3266
3267 return new (Context) IndirectGotoStmt(GotoLoc, StarLoc, E);
3268}
3269
3270static void CheckJumpOutOfSEHFinally(Sema &S, SourceLocation Loc,
3271 const Scope &DestScope) {
3272 if (!S.CurrentSEHFinally.empty() &&
3273 DestScope.Contains(*S.CurrentSEHFinally.back())) {
3274 S.Diag(Loc, diag::warn_jump_out_of_seh_finally);
3275 }
3276}
3277
3278StmtResult
3279Sema::ActOnContinueStmt(SourceLocation ContinueLoc, Scope *CurScope) {
3280 Scope *S = CurScope->getContinueParent();
3281 if (!S) {
3282 // C99 6.8.6.2p1: A break shall appear only in or as a loop body.
3283 return StmtError(Diag(ContinueLoc, diag::err_continue_not_in_loop));
3284 }
3285 if (S->getFlags() & Scope::ConditionVarScope) {
3286 // We cannot 'continue;' from within a statement expression in the
3287 // initializer of a condition variable because we would jump past the
3288 // initialization of that variable.
3289 return StmtError(Diag(ContinueLoc, diag::err_continue_from_cond_var_init));
3290 }
3291 CheckJumpOutOfSEHFinally(*this, ContinueLoc, *S);
3292
3293 return new (Context) ContinueStmt(ContinueLoc);
3294}
3295
3296StmtResult
3297Sema::ActOnBreakStmt(SourceLocation BreakLoc, Scope *CurScope) {
3298 Scope *S = CurScope->getBreakParent();
3299 if (!S) {
3300 // C99 6.8.6.3p1: A break shall appear only in or as a switch/loop body.
3301 return StmtError(Diag(BreakLoc, diag::err_break_not_in_loop_or_switch));
3302 }
3303 if (S->isOpenMPLoopScope())
3304 return StmtError(Diag(BreakLoc, diag::err_omp_loop_cannot_use_stmt)
3305 << "break");
3306 CheckJumpOutOfSEHFinally(*this, BreakLoc, *S);
3307
3308 return new (Context) BreakStmt(BreakLoc);
3309}
3310
3311/// Determine whether the given expression might be move-eligible or
3312/// copy-elidable in either a (co_)return statement or throw expression,
3313/// without considering function return type, if applicable.
3314///
3315/// \param E The expression being returned from the function or block,
3316/// being thrown, or being co_returned from a coroutine. This expression
3317/// might be modified by the implementation.
3318///
3319/// \param Mode Overrides detection of current language mode
3320/// and uses the rules for C++2b.
3321///
3322/// \returns An aggregate which contains the Candidate and isMoveEligible
3323/// and isCopyElidable methods. If Candidate is non-null, it means
3324/// isMoveEligible() would be true under the most permissive language standard.
3325Sema::NamedReturnInfo Sema::getNamedReturnInfo(Expr *&E,
3326 SimplerImplicitMoveMode Mode) {
3327 if (!E)
3328 return NamedReturnInfo();
3329 // - in a return statement in a function [where] ...
3330 // ... the expression is the name of a non-volatile automatic object ...
3331 const auto *DR = dyn_cast<DeclRefExpr>(E->IgnoreParens());
3332 if (!DR || DR->refersToEnclosingVariableOrCapture())
3333 return NamedReturnInfo();
3334 const auto *VD = dyn_cast<VarDecl>(DR->getDecl());
3335 if (!VD)
3336 return NamedReturnInfo();
3337 NamedReturnInfo Res = getNamedReturnInfo(VD);
3338 if (Res.Candidate && !E->isXValue() &&
3339 (Mode == SimplerImplicitMoveMode::ForceOn ||
3340 (Mode != SimplerImplicitMoveMode::ForceOff &&
3341 getLangOpts().CPlusPlus2b))) {
3342 E = ImplicitCastExpr::Create(Context, VD->getType().getNonReferenceType(),
3343 CK_NoOp, E, nullptr, VK_XValue,
3344 FPOptionsOverride());
3345 }
3346 return Res;
3347}
3348
3349/// Determine whether the given NRVO candidate variable is move-eligible or
3350/// copy-elidable, without considering function return type.
3351///
3352/// \param VD The NRVO candidate variable.
3353///
3354/// \returns An aggregate which contains the Candidate and isMoveEligible
3355/// and isCopyElidable methods. If Candidate is non-null, it means
3356/// isMoveEligible() would be true under the most permissive language standard.
3357Sema::NamedReturnInfo Sema::getNamedReturnInfo(const VarDecl *VD) {
3358 NamedReturnInfo Info{VD, NamedReturnInfo::MoveEligibleAndCopyElidable};
3359
3360 // C++20 [class.copy.elision]p3:
3361 // - in a return statement in a function with ...
3362 // (other than a function ... parameter)
3363 if (VD->getKind() == Decl::ParmVar)
3364 Info.S = NamedReturnInfo::MoveEligible;
3365 else if (VD->getKind() != Decl::Var)
3366 return NamedReturnInfo();
3367
3368 // (other than ... a catch-clause parameter)
3369 if (VD->isExceptionVariable())
3370 Info.S = NamedReturnInfo::MoveEligible;
3371
3372 // ...automatic...
3373 if (!VD->hasLocalStorage())
3374 return NamedReturnInfo();
3375
3376 // We don't want to implicitly move out of a __block variable during a return
3377 // because we cannot assume the variable will no longer be used.
3378 if (VD->hasAttr<BlocksAttr>())
3379 return NamedReturnInfo();
3380
3381 QualType VDType = VD->getType();
3382 if (VDType->isObjectType()) {
3383 // C++17 [class.copy.elision]p3:
3384 // ...non-volatile automatic object...
3385 if (VDType.isVolatileQualified())
3386 return NamedReturnInfo();
3387 } else if (VDType->isRValueReferenceType()) {
3388 // C++20 [class.copy.elision]p3:
3389 // ...either a non-volatile object or an rvalue reference to a non-volatile
3390 // object type...
3391 QualType VDReferencedType = VDType.getNonReferenceType();
3392 if (VDReferencedType.isVolatileQualified() ||
3393 !VDReferencedType->isObjectType())
3394 return NamedReturnInfo();
3395 Info.S = NamedReturnInfo::MoveEligible;
3396 } else {
3397 return NamedReturnInfo();
3398 }
3399
3400 // Variables with higher required alignment than their type's ABI
3401 // alignment cannot use NRVO.
3402 if (!VD->hasDependentAlignment() &&
3403 Context.getDeclAlign(VD) > Context.getTypeAlignInChars(VDType))
3404 Info.S = NamedReturnInfo::MoveEligible;
3405
3406 return Info;
3407}
3408
3409/// Updates given NamedReturnInfo's move-eligible and
3410/// copy-elidable statuses, considering the function
3411/// return type criteria as applicable to return statements.
3412///
3413/// \param Info The NamedReturnInfo object to update.
3414///
3415/// \param ReturnType This is the return type of the function.
3416/// \returns The copy elision candidate, in case the initial return expression
3417/// was copy elidable, or nullptr otherwise.
3418const VarDecl *Sema::getCopyElisionCandidate(NamedReturnInfo &Info,
3419 QualType ReturnType) {
3420 if (!Info.Candidate)
3421 return nullptr;
3422
3423 auto invalidNRVO = [&] {
3424 Info = NamedReturnInfo();
3425 return nullptr;
3426 };
3427
3428 // If we got a non-deduced auto ReturnType, we are in a dependent context and
3429 // there is no point in allowing copy elision since we won't have it deduced
3430 // by the point the VardDecl is instantiated, which is the last chance we have
3431 // of deciding if the candidate is really copy elidable.
3432 if ((ReturnType->getTypeClass() == Type::TypeClass::Auto &&
3433 ReturnType->isCanonicalUnqualified()) ||
3434 ReturnType->isSpecificBuiltinType(BuiltinType::Dependent))
3435 return invalidNRVO();
3436
3437 if (!ReturnType->isDependentType()) {
3438 // - in a return statement in a function with ...
3439 // ... a class return type ...
3440 if (!ReturnType->isRecordType())
3441 return invalidNRVO();
3442
3443 QualType VDType = Info.Candidate->getType();
3444 // ... the same cv-unqualified type as the function return type ...
3445 // When considering moving this expression out, allow dissimilar types.
3446 if (!VDType->isDependentType() &&
3447 !Context.hasSameUnqualifiedType(ReturnType, VDType))
3448 Info.S = NamedReturnInfo::MoveEligible;
3449 }
3450 return Info.isCopyElidable() ? Info.Candidate : nullptr;
3451}
3452
3453/// Verify that the initialization sequence that was picked for the
3454/// first overload resolution is permissible under C++98.
3455///
3456/// Reject (possibly converting) contructors not taking an rvalue reference,
3457/// or user conversion operators which are not ref-qualified.
3458static bool
3459VerifyInitializationSequenceCXX98(const Sema &S,
3460 const InitializationSequence &Seq) {
3461 const auto *Step = llvm::find_if(Seq.steps(), [](const auto &Step) {
3462 return Step.Kind == InitializationSequence::SK_ConstructorInitialization ||
3463 Step.Kind == InitializationSequence::SK_UserConversion;
3464 });
3465 if (Step != Seq.step_end()) {
3466 const auto *FD = Step->Function.Function;
3467 if (isa<CXXConstructorDecl>(FD)
3468 ? !FD->getParamDecl(0)->getType()->isRValueReferenceType()
3469 : cast<CXXMethodDecl>(FD)->getRefQualifier() == RQ_None)
3470 return false;
3471 }
3472 return true;
3473}
3474
3475/// Perform the initialization of a potentially-movable value, which
3476/// is the result of return value.
3477///
3478/// This routine implements C++20 [class.copy.elision]p3, which attempts to
3479/// treat returned lvalues as rvalues in certain cases (to prefer move
3480/// construction), then falls back to treating them as lvalues if that failed.
3481ExprResult Sema::PerformMoveOrCopyInitialization(
3482 const InitializedEntity &Entity, const NamedReturnInfo &NRInfo, Expr *Value,
3483 bool SupressSimplerImplicitMoves) {
3484 if ((!getLangOpts().CPlusPlus2b || SupressSimplerImplicitMoves) &&
3485 NRInfo.isMoveEligible()) {
3486 ImplicitCastExpr AsRvalue(ImplicitCastExpr::OnStack, Value->getType(),
3487 CK_NoOp, Value, VK_XValue, FPOptionsOverride());
3488 Expr *InitExpr = &AsRvalue;
3489 auto Kind = InitializationKind::CreateCopy(Value->getBeginLoc(),
3490 Value->getBeginLoc());
3491 InitializationSequence Seq(*this, Entity, Kind, InitExpr);
3492 auto Res = Seq.getFailedOverloadResult();
3493 if ((Res == OR_Success || Res == OR_Deleted) &&
3494 (getLangOpts().CPlusPlus11 ||
3495 VerifyInitializationSequenceCXX98(*this, Seq))) {
3496 // Promote "AsRvalue" to the heap, since we now need this
3497 // expression node to persist.
3498 Value =
3499 ImplicitCastExpr::Create(Context, Value->getType(), CK_NoOp, Value,
3500 nullptr, VK_XValue, FPOptionsOverride());
3501 // Complete type-checking the initialization of the return type
3502 // using the constructor we found.
3503 return Seq.Perform(*this, Entity, Kind, Value);
3504 }
3505 }
3506 // Either we didn't meet the criteria for treating an lvalue as an rvalue,
3507 // above, or overload resolution failed. Either way, we need to try
3508 // (again) now with the return value expression as written.
3509 return PerformCopyInitialization(Entity, SourceLocation(), Value);
3510}
3511
3512/// Determine whether the declared return type of the specified function
3513/// contains 'auto'.
3514static bool hasDeducedReturnType(FunctionDecl *FD) {
3515 const FunctionProtoType *FPT =
3516 FD->getTypeSourceInfo()->getType()->castAs<FunctionProtoType>();
3517 return FPT->getReturnType()->isUndeducedType();
3518}
3519
3520/// ActOnCapScopeReturnStmt - Utility routine to type-check return statements
3521/// for capturing scopes.
3522///
3523StmtResult Sema::ActOnCapScopeReturnStmt(SourceLocation ReturnLoc,
3524 Expr *RetValExp,
3525 NamedReturnInfo &NRInfo,
3526 bool SupressSimplerImplicitMoves) {
3527 // If this is the first return we've seen, infer the return type.
3528 // [expr.prim.lambda]p4 in C++11; block literals follow the same rules.
3529 CapturingScopeInfo *CurCap = cast<CapturingScopeInfo>(getCurFunction());
6
The object is a 'CapturingScopeInfo'
3530 QualType FnRetType = CurCap->ReturnType;
3531 LambdaScopeInfo *CurLambda = dyn_cast<LambdaScopeInfo>(CurCap);
7
Assuming 'CurCap' is not a 'LambdaScopeInfo'
8
'CurLambda' initialized to a null pointer value
3532 bool HasDeducedReturnType =
3533 CurLambda
8.1
'CurLambda' is null
&& hasDeducedReturnType(CurLambda->CallOperator);
3534
3535 if (ExprEvalContexts.back().Context ==
9
Assuming field 'Context' is not equal to DiscardedStatement
3536 ExpressionEvaluationContext::DiscardedStatement &&
3537 (HasDeducedReturnType || CurCap->HasImplicitReturnType)) {
3538 if (RetValExp) {
3539 ExprResult ER =
3540 ActOnFinishFullExpr(RetValExp, ReturnLoc, /*DiscardedValue*/ false);
3541 if (ER.isInvalid())
3542 return StmtError();
3543 RetValExp = ER.get();
3544 }
3545 return ReturnStmt::Create(Context, ReturnLoc, RetValExp,
3546 /* NRVOCandidate=*/nullptr);
3547 }
3548
3549 if (HasDeducedReturnType
9.1
'HasDeducedReturnType' is false
) {
10
Taking false branch
3550 FunctionDecl *FD = CurLambda->CallOperator;
3551 // If we've already decided this lambda is invalid, e.g. because
3552 // we saw a `return` whose expression had an error, don't keep
3553 // trying to deduce its return type.
3554 if (FD->isInvalidDecl())
3555 return StmtError();
3556 // In C++1y, the return type may involve 'auto'.
3557 // FIXME: Blocks might have a return type of 'auto' explicitly specified.
3558 if (CurCap->ReturnType.isNull())
3559 CurCap->ReturnType = FD->getReturnType();
3560
3561 AutoType *AT = CurCap->ReturnType->getContainedAutoType();
3562 assert(AT && "lost auto type from lambda return type")(static_cast<void> (0));
3563 if (DeduceFunctionTypeFromReturnExpr(FD, ReturnLoc, RetValExp, AT)) {
3564 FD->setInvalidDecl();
3565 // FIXME: preserve the ill-formed return expression.
3566 return StmtError();
3567 }
3568 CurCap->ReturnType = FnRetType = FD->getReturnType();
3569 } else if (CurCap->HasImplicitReturnType) {
11
Assuming field 'HasImplicitReturnType' is false
12
Taking false branch
3570 // For blocks/lambdas with implicit return types, we check each return
3571 // statement individually, and deduce the common return type when the block
3572 // or lambda is completed.
3573 // FIXME: Fold this into the 'auto' codepath above.
3574 if (RetValExp && !isa<InitListExpr>(RetValExp)) {
3575 ExprResult Result = DefaultFunctionArrayLvalueConversion(RetValExp);
3576 if (Result.isInvalid())
3577 return StmtError();
3578 RetValExp = Result.get();
3579
3580 // DR1048: even prior to C++14, we should use the 'auto' deduction rules
3581 // when deducing a return type for a lambda-expression (or by extension
3582 // for a block). These rules differ from the stated C++11 rules only in
3583 // that they remove top-level cv-qualifiers.
3584 if (!CurContext->isDependentContext())
3585 FnRetType = RetValExp->getType().getUnqualifiedType();
3586 else
3587 FnRetType = CurCap->ReturnType = Context.DependentTy;
3588 } else {
3589 if (RetValExp) {
3590 // C++11 [expr.lambda.prim]p4 bans inferring the result from an
3591 // initializer list, because it is not an expression (even
3592 // though we represent it as one). We still deduce 'void'.
3593 Diag(ReturnLoc, diag::err_lambda_return_init_list)
3594 << RetValExp->getSourceRange();
3595 }
3596
3597 FnRetType = Context.VoidTy;
3598 }
3599
3600 // Although we'll properly infer the type of the block once it's completed,
3601 // make sure we provide a return type now for better error recovery.
3602 if (CurCap->ReturnType.isNull())
3603 CurCap->ReturnType = FnRetType;
3604 }
3605 const VarDecl *NRVOCandidate = getCopyElisionCandidate(NRInfo, FnRetType);
3606
3607 if (auto *CurBlock
13.1
'CurBlock' is null
= dyn_cast<BlockScopeInfo>(CurCap)) {
13
Assuming 'CurCap' is not a 'BlockScopeInfo'
14
Taking false branch
3608 if (CurBlock->FunctionType->castAs<FunctionType>()->getNoReturnAttr()) {
3609 Diag(ReturnLoc, diag::err_noreturn_block_has_return_expr);
3610 return StmtError();
3611 }
3612 } else if (auto *CurRegion
15.1
'CurRegion' is null
= dyn_cast<CapturedRegionScopeInfo>(CurCap)) {
15
Assuming 'CurCap' is not a 'CapturedRegionScopeInfo'
16
Taking false branch
3613 Diag(ReturnLoc, diag::err_return_in_captured_stmt) << CurRegion->getRegionName();
3614 return StmtError();
3615 } else {
3616 assert(CurLambda && "unknown kind of captured scope")(static_cast<void> (0));
3617 if (CurLambda->CallOperator->getType()
17
Access to field 'CallOperator' results in a dereference of a null pointer (loaded from variable 'CurLambda')
3618 ->castAs<FunctionType>()
3619 ->getNoReturnAttr()) {
3620 Diag(ReturnLoc, diag::err_noreturn_lambda_has_return_expr);
3621 return StmtError();
3622 }
3623 }
3624
3625 // Otherwise, verify that this result type matches the previous one. We are
3626 // pickier with blocks than for normal functions because we don't have GCC
3627 // compatibility to worry about here.
3628 if (FnRetType->isDependentType()) {
3629 // Delay processing for now. TODO: there are lots of dependent
3630 // types we can conclusively prove aren't void.
3631 } else if (FnRetType->isVoidType()) {
3632 if (RetValExp && !isa<InitListExpr>(RetValExp) &&
3633 !(getLangOpts().CPlusPlus &&
3634 (RetValExp->isTypeDependent() ||
3635 RetValExp->getType()->isVoidType()))) {
3636 if (!getLangOpts().CPlusPlus &&
3637 RetValExp->getType()->isVoidType())
3638 Diag(ReturnLoc, diag::ext_return_has_void_expr) << "literal" << 2;
3639 else {
3640 Diag(ReturnLoc, diag::err_return_block_has_expr);
3641 RetValExp = nullptr;
3642 }
3643 }
3644 } else if (!RetValExp) {
3645 return StmtError(Diag(ReturnLoc, diag::err_block_return_missing_expr));
3646 } else if (!RetValExp->isTypeDependent()) {
3647 // we have a non-void block with an expression, continue checking
3648
3649 // C99 6.8.6.4p3(136): The return statement is not an assignment. The
3650 // overlap restriction of subclause 6.5.16.1 does not apply to the case of
3651 // function return.
3652
3653 // In C++ the return statement is handled via a copy initialization.
3654 // the C version of which boils down to CheckSingleAssignmentConstraints.
3655 InitializedEntity Entity = InitializedEntity::InitializeResult(
3656 ReturnLoc, FnRetType, NRVOCandidate != nullptr);
3657 ExprResult Res = PerformMoveOrCopyInitialization(
3658 Entity, NRInfo, RetValExp, SupressSimplerImplicitMoves);
3659 if (Res.isInvalid()) {
3660 // FIXME: Cleanup temporaries here, anyway?
3661 return StmtError();
3662 }
3663 RetValExp = Res.get();
3664 CheckReturnValExpr(RetValExp, FnRetType, ReturnLoc);
3665 }
3666
3667 if (RetValExp) {
3668 ExprResult ER =
3669 ActOnFinishFullExpr(RetValExp, ReturnLoc, /*DiscardedValue*/ false);
3670 if (ER.isInvalid())
3671 return StmtError();
3672 RetValExp = ER.get();
3673 }
3674 auto *Result =
3675 ReturnStmt::Create(Context, ReturnLoc, RetValExp, NRVOCandidate);
3676
3677 // If we need to check for the named return value optimization,
3678 // or if we need to infer the return type,
3679 // save the return statement in our scope for later processing.
3680 if (CurCap->HasImplicitReturnType || NRVOCandidate)
3681 FunctionScopes.back()->Returns.push_back(Result);
3682
3683 if (FunctionScopes.back()->FirstReturnLoc.isInvalid())
3684 FunctionScopes.back()->FirstReturnLoc = ReturnLoc;
3685
3686 return Result;
3687}
3688
3689namespace {
3690/// Marks all typedefs in all local classes in a type referenced.
3691///
3692/// In a function like
3693/// auto f() {
3694/// struct S { typedef int a; };
3695/// return S();
3696/// }
3697///
3698/// the local type escapes and could be referenced in some TUs but not in
3699/// others. Pretend that all local typedefs are always referenced, to not warn
3700/// on this. This isn't necessary if f has internal linkage, or the typedef
3701/// is private.
3702class LocalTypedefNameReferencer
3703 : public RecursiveASTVisitor<LocalTypedefNameReferencer> {
3704public:
3705 LocalTypedefNameReferencer(Sema &S) : S(S) {}
3706 bool VisitRecordType(const RecordType *RT);
3707private:
3708 Sema &S;
3709};
3710bool LocalTypedefNameReferencer::VisitRecordType(const RecordType *RT) {
3711 auto *R = dyn_cast<CXXRecordDecl>(RT->getDecl());
3712 if (!R || !R->isLocalClass() || !R->isLocalClass()->isExternallyVisible() ||
3713 R->isDependentType())
3714 return true;
3715 for (auto *TmpD : R->decls())
3716 if (auto *T = dyn_cast<TypedefNameDecl>(TmpD))
3717 if (T->getAccess() != AS_private || R->hasFriends())
3718 S.MarkAnyDeclReferenced(T->getLocation(), T, /*OdrUse=*/false);
3719 return true;
3720}
3721}
3722
3723TypeLoc Sema::getReturnTypeLoc(FunctionDecl *FD) const {
3724 return FD->getTypeSourceInfo()
3725 ->getTypeLoc()
3726 .getAsAdjusted<FunctionProtoTypeLoc>()
3727 .getReturnLoc();
3728}
3729
3730/// Deduce the return type for a function from a returned expression, per
3731/// C++1y [dcl.spec.auto]p6.
3732bool Sema::DeduceFunctionTypeFromReturnExpr(FunctionDecl *FD,
3733 SourceLocation ReturnLoc,
3734 Expr *&RetExpr,
3735 AutoType *AT) {
3736 // If this is the conversion function for a lambda, we choose to deduce it
3737 // type from the corresponding call operator, not from the synthesized return
3738 // statement within it. See Sema::DeduceReturnType.
3739 if (isLambdaConversionOperator(FD))
3740 return false;
3741
3742 TypeLoc OrigResultType = getReturnTypeLoc(FD);
3743 QualType Deduced;
3744
3745 if (RetExpr && isa<InitListExpr>(RetExpr)) {
3746 // If the deduction is for a return statement and the initializer is
3747 // a braced-init-list, the program is ill-formed.
3748 Diag(RetExpr->getExprLoc(),
3749 getCurLambda() ? diag::err_lambda_return_init_list
3750 : diag::err_auto_fn_return_init_list)
3751 << RetExpr->getSourceRange();
3752 return true;
3753 }
3754
3755 if (FD->isDependentContext()) {
3756 // C++1y [dcl.spec.auto]p12:
3757 // Return type deduction [...] occurs when the definition is
3758 // instantiated even if the function body contains a return
3759 // statement with a non-type-dependent operand.
3760 assert(AT->isDeduced() && "should have deduced to dependent type")(static_cast<void> (0));
3761 return false;
3762 }
3763
3764 if (RetExpr) {
3765 // Otherwise, [...] deduce a value for U using the rules of template
3766 // argument deduction.
3767 DeduceAutoResult DAR = DeduceAutoType(OrigResultType, RetExpr, Deduced);
3768
3769 if (DAR == DAR_Failed && !FD->isInvalidDecl())
3770 Diag(RetExpr->getExprLoc(), diag::err_auto_fn_deduction_failure)
3771 << OrigResultType.getType() << RetExpr->getType();
3772
3773 if (DAR != DAR_Succeeded)
3774 return true;
3775
3776 // If a local type is part of the returned type, mark its fields as
3777 // referenced.
3778 LocalTypedefNameReferencer Referencer(*this);
3779 Referencer.TraverseType(RetExpr->getType());
3780 } else {
3781 // In the case of a return with no operand, the initializer is considered
3782 // to be void().
3783 //
3784 // Deduction here can only succeed if the return type is exactly 'cv auto'
3785 // or 'decltype(auto)', so just check for that case directly.
3786 if (!OrigResultType.getType()->getAs<AutoType>()) {
3787 Diag(ReturnLoc, diag::err_auto_fn_return_void_but_not_auto)
3788 << OrigResultType.getType();
3789 return true;
3790 }
3791 // We always deduce U = void in this case.
3792 Deduced = SubstAutoType(OrigResultType.getType(), Context.VoidTy);
3793 if (Deduced.isNull())
3794 return true;
3795 }
3796
3797 // CUDA: Kernel function must have 'void' return type.
3798 if (getLangOpts().CUDA)
3799 if (FD->hasAttr<CUDAGlobalAttr>() && !Deduced->isVoidType()) {
3800 Diag(FD->getLocation(), diag::err_kern_type_not_void_return)
3801 << FD->getType() << FD->getSourceRange();
3802 return true;
3803 }
3804
3805 // If a function with a declared return type that contains a placeholder type
3806 // has multiple return statements, the return type is deduced for each return
3807 // statement. [...] if the type deduced is not the same in each deduction,
3808 // the program is ill-formed.
3809 QualType DeducedT = AT->getDeducedType();
3810 if (!DeducedT.isNull() && !FD->isInvalidDecl()) {
3811 AutoType *NewAT = Deduced->getContainedAutoType();
3812 // It is possible that NewAT->getDeducedType() is null. When that happens,
3813 // we should not crash, instead we ignore this deduction.
3814 if (NewAT->getDeducedType().isNull())
3815 return false;
3816
3817 CanQualType OldDeducedType = Context.getCanonicalFunctionResultType(
3818 DeducedT);
3819 CanQualType NewDeducedType = Context.getCanonicalFunctionResultType(
3820 NewAT->getDeducedType());
3821 if (!FD->isDependentContext() && OldDeducedType != NewDeducedType) {
3822 const LambdaScopeInfo *LambdaSI = getCurLambda();
3823 if (LambdaSI && LambdaSI->HasImplicitReturnType) {
3824 Diag(ReturnLoc, diag::err_typecheck_missing_return_type_incompatible)
3825 << NewAT->getDeducedType() << DeducedT
3826 << true /*IsLambda*/;
3827 } else {
3828 Diag(ReturnLoc, diag::err_auto_fn_different_deductions)
3829 << (AT->isDecltypeAuto() ? 1 : 0)
3830 << NewAT->getDeducedType() << DeducedT;
3831 }
3832 return true;
3833 }
3834 } else if (!FD->isInvalidDecl()) {
3835 // Update all declarations of the function to have the deduced return type.
3836 Context.adjustDeducedFunctionResultType(FD, Deduced);
3837 }
3838
3839 return false;
3840}
3841
3842StmtResult
3843Sema::ActOnReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp,
3844 Scope *CurScope) {
3845 // Correct typos, in case the containing function returns 'auto' and
3846 // RetValExp should determine the deduced type.
3847 ExprResult RetVal = CorrectDelayedTyposInExpr(
3848 RetValExp, nullptr, /*RecoverUncorrectedTypos=*/true);
3849 if (RetVal.isInvalid())
3850 return StmtError();
3851 StmtResult R = BuildReturnStmt(ReturnLoc, RetVal.get());
3852 if (R.isInvalid() || ExprEvalContexts.back().Context ==
3853 ExpressionEvaluationContext::DiscardedStatement)
3854 return R;
3855
3856 if (VarDecl *VD =
3857 const_cast<VarDecl*>(cast<ReturnStmt>(R.get())->getNRVOCandidate())) {
3858 CurScope->addNRVOCandidate(VD);
3859 } else {
3860 CurScope->setNoNRVO();
3861 }
3862
3863 CheckJumpOutOfSEHFinally(*this, ReturnLoc, *CurScope->getFnParent());
3864
3865 return R;
3866}
3867
3868static bool CheckSimplerImplicitMovesMSVCWorkaround(const Sema &S,
3869 const Expr *E) {
3870 if (!E || !S.getLangOpts().CPlusPlus2b || !S.getLangOpts().MSVCCompat)
3871 return false;
3872 const Decl *D = E->getReferencedDeclOfCallee();
3873 if (!D || !S.SourceMgr.isInSystemHeader(D->getLocation()))
3874 return false;
3875 for (const DeclContext *DC = D->getDeclContext(); DC; DC = DC->getParent()) {
3876 if (DC->isStdNamespace())
3877 return true;
3878 }
3879 return false;
3880}
3881
3882StmtResult Sema::BuildReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp) {
3883 // Check for unexpanded parameter packs.
3884 if (RetValExp && DiagnoseUnexpandedParameterPack(RetValExp))
1
Assuming 'RetValExp' is null
3885 return StmtError();
3886
3887 // HACK: We supress simpler implicit move here in msvc compatibility mode
3888 // just as a temporary work around, as the MSVC STL has issues with
3889 // this change.
3890 bool SupressSimplerImplicitMoves =
3891 CheckSimplerImplicitMovesMSVCWorkaround(*this, RetValExp);
3892 NamedReturnInfo NRInfo = getNamedReturnInfo(
3893 RetValExp, SupressSimplerImplicitMoves
1.1
'SupressSimplerImplicitMoves' is false
? SimplerImplicitMoveMode::ForceOff
2
'?' condition is false
3894 : SimplerImplicitMoveMode::Normal);
3895
3896 if (isa<CapturingScopeInfo>(getCurFunction()))
3
Assuming the object is a 'CapturingScopeInfo'
4
Taking true branch
3897 return ActOnCapScopeReturnStmt(ReturnLoc, RetValExp, NRInfo,
5
Calling 'Sema::ActOnCapScopeReturnStmt'
3898 SupressSimplerImplicitMoves);
3899
3900 QualType FnRetType;
3901 QualType RelatedRetType;
3902 const AttrVec *Attrs = nullptr;
3903 bool isObjCMethod = false;
3904
3905 if (const FunctionDecl *FD = getCurFunctionDecl()) {
3906 FnRetType = FD->getReturnType();
3907 if (FD->hasAttrs())
3908 Attrs = &FD->getAttrs();
3909 if (FD->isNoReturn())
3910 Diag(ReturnLoc, diag::warn_noreturn_function_has_return_expr) << FD;
3911 if (FD->isMain() && RetValExp)
3912 if (isa<CXXBoolLiteralExpr>(RetValExp))
3913 Diag(ReturnLoc, diag::warn_main_returns_bool_literal)
3914 << RetValExp->getSourceRange();
3915 if (FD->hasAttr<CmseNSEntryAttr>() && RetValExp) {
3916 if (const auto *RT = dyn_cast<RecordType>(FnRetType.getCanonicalType())) {
3917 if (RT->getDecl()->isOrContainsUnion())
3918 Diag(RetValExp->getBeginLoc(), diag::warn_cmse_nonsecure_union) << 1;
3919 }
3920 }
3921 } else if (ObjCMethodDecl *MD = getCurMethodDecl()) {
3922 FnRetType = MD->getReturnType();
3923 isObjCMethod = true;
3924 if (MD->hasAttrs())
3925 Attrs = &MD->getAttrs();
3926 if (MD->hasRelatedResultType() && MD->getClassInterface()) {
3927 // In the implementation of a method with a related return type, the
3928 // type used to type-check the validity of return statements within the
3929 // method body is a pointer to the type of the class being implemented.
3930 RelatedRetType = Context.getObjCInterfaceType(MD->getClassInterface());
3931 RelatedRetType = Context.getObjCObjectPointerType(RelatedRetType);
3932 }
3933 } else // If we don't have a function/method context, bail.
3934 return StmtError();
3935
3936 // C++1z: discarded return statements are not considered when deducing a
3937 // return type.
3938 if (ExprEvalContexts.back().Context ==
3939 ExpressionEvaluationContext::DiscardedStatement &&
3940 FnRetType->getContainedAutoType()) {
3941 if (RetValExp) {
3942 ExprResult ER =
3943 ActOnFinishFullExpr(RetValExp, ReturnLoc, /*DiscardedValue*/ false);
3944 if (ER.isInvalid())
3945 return StmtError();
3946 RetValExp = ER.get();
3947 }
3948 return ReturnStmt::Create(Context, ReturnLoc, RetValExp,
3949 /* NRVOCandidate=*/nullptr);
3950 }
3951
3952 // FIXME: Add a flag to the ScopeInfo to indicate whether we're performing
3953 // deduction.
3954 if (getLangOpts().CPlusPlus14) {
3955 if (AutoType *AT = FnRetType->getContainedAutoType()) {
3956 FunctionDecl *FD = cast<FunctionDecl>(CurContext);
3957 // If we've already decided this function is invalid, e.g. because
3958 // we saw a `return` whose expression had an error, don't keep
3959 // trying to deduce its return type.
3960 if (FD->isInvalidDecl())
3961 return StmtError();
3962 if (DeduceFunctionTypeFromReturnExpr(FD, ReturnLoc, RetValExp, AT)) {
3963 FD->setInvalidDecl();
3964 return StmtError();
3965 } else {
3966 FnRetType = FD->getReturnType();
3967 }
3968 }
3969 }
3970 const VarDecl *NRVOCandidate = getCopyElisionCandidate(NRInfo, FnRetType);
3971
3972 bool HasDependentReturnType = FnRetType->isDependentType();
3973
3974 ReturnStmt *Result = nullptr;
3975 if (FnRetType->isVoidType()) {
3976 if (RetValExp) {
3977 if (isa<InitListExpr>(RetValExp)) {
3978 // We simply never allow init lists as the return value of void
3979 // functions. This is compatible because this was never allowed before,
3980 // so there's no legacy code to deal with.
3981 NamedDecl *CurDecl = getCurFunctionOrMethodDecl();
3982 int FunctionKind = 0;
3983 if (isa<ObjCMethodDecl>(CurDecl))
3984 FunctionKind = 1;
3985 else if (isa<CXXConstructorDecl>(CurDecl))
3986 FunctionKind = 2;
3987 else if (isa<CXXDestructorDecl>(CurDecl))
3988 FunctionKind = 3;
3989
3990 Diag(ReturnLoc, diag::err_return_init_list)
3991 << CurDecl << FunctionKind << RetValExp->getSourceRange();
3992
3993 // Drop the expression.
3994 RetValExp = nullptr;
3995 } else if (!RetValExp->isTypeDependent()) {
3996 // C99 6.8.6.4p1 (ext_ since GCC warns)
3997 unsigned D = diag::ext_return_has_expr;
3998 if (RetValExp->getType()->isVoidType()) {
3999 NamedDecl *CurDecl = getCurFunctionOrMethodDecl();
4000 if (isa<CXXConstructorDecl>(CurDecl) ||
4001 isa<CXXDestructorDecl>(CurDecl))
4002 D = diag::err_ctor_dtor_returns_void;
4003 else
4004 D = diag::ext_return_has_void_expr;
4005 }
4006 else {
4007 ExprResult Result = RetValExp;
4008 Result = IgnoredValueConversions(Result.get());
4009 if (Result.isInvalid())
4010 return StmtError();
4011 RetValExp = Result.get();
4012 RetValExp = ImpCastExprToType(RetValExp,
4013 Context.VoidTy, CK_ToVoid).get();
4014 }
4015 // return of void in constructor/destructor is illegal in C++.
4016 if (D == diag::err_ctor_dtor_returns_void) {
4017 NamedDecl *CurDecl = getCurFunctionOrMethodDecl();
4018 Diag(ReturnLoc, D) << CurDecl << isa<CXXDestructorDecl>(CurDecl)
4019 << RetValExp->getSourceRange();
4020 }
4021 // return (some void expression); is legal in C++.
4022 else if (D != diag::ext_return_has_void_expr ||
4023 !getLangOpts().CPlusPlus) {
4024 NamedDecl *CurDecl = getCurFunctionOrMethodDecl();
4025
4026 int FunctionKind = 0;
4027 if (isa<ObjCMethodDecl>(CurDecl))
4028 FunctionKind = 1;
4029 else if (isa<CXXConstructorDecl>(CurDecl))
4030 FunctionKind = 2;
4031 else if (isa<CXXDestructorDecl>(CurDecl))
4032 FunctionKind = 3;
4033
4034 Diag(ReturnLoc, D)
4035 << CurDecl << FunctionKind << RetValExp->getSourceRange();
4036 }
4037 }
4038
4039 if (RetValExp) {
4040 ExprResult ER =
4041 ActOnFinishFullExpr(RetValExp, ReturnLoc, /*DiscardedValue*/ false);
4042 if (ER.isInvalid())
4043 return StmtError();
4044 RetValExp = ER.get();
4045 }
4046 }
4047
4048 Result = ReturnStmt::Create(Context, ReturnLoc, RetValExp,
4049 /* NRVOCandidate=*/nullptr);
4050 } else if (!RetValExp && !HasDependentReturnType) {
4051 FunctionDecl *FD = getCurFunctionDecl();
4052
4053 if (getLangOpts().CPlusPlus11 && FD && FD->isConstexpr()) {
4054 // C++11 [stmt.return]p2
4055 Diag(ReturnLoc, diag::err_constexpr_return_missing_expr)
4056 << FD << FD->isConsteval();
4057 FD->setInvalidDecl();
4058 } else {
4059 // C99 6.8.6.4p1 (ext_ since GCC warns)
4060 // C90 6.6.6.4p4
4061 unsigned DiagID = getLangOpts().C99 ? diag::ext_return_missing_expr
4062 : diag::warn_return_missing_expr;
4063 // Note that at this point one of getCurFunctionDecl() or
4064 // getCurMethodDecl() must be non-null (see above).
4065 assert((getCurFunctionDecl() || getCurMethodDecl()) &&(static_cast<void> (0))
4066 "Not in a FunctionDecl or ObjCMethodDecl?")(static_cast<void> (0));
4067 bool IsMethod = FD == nullptr;
4068 const NamedDecl *ND =
4069 IsMethod ? cast<NamedDecl>(getCurMethodDecl()) : cast<NamedDecl>(FD);
4070 Diag(ReturnLoc, DiagID) << ND << IsMethod;
4071 }
4072
4073 Result = ReturnStmt::Create(Context, ReturnLoc, /* RetExpr=*/nullptr,
4074 /* NRVOCandidate=*/nullptr);
4075 } else {
4076 assert(RetValExp || HasDependentReturnType)(static_cast<void> (0));
4077 QualType RetType = RelatedRetType.isNull() ? FnRetType : RelatedRetType;
4078
4079 // C99 6.8.6.4p3(136): The return statement is not an assignment. The
4080 // overlap restriction of subclause 6.5.16.1 does not apply to the case of
4081 // function return.
4082
4083 // In C++ the return statement is handled via a copy initialization,
4084 // the C version of which boils down to CheckSingleAssignmentConstraints.
4085 if (!HasDependentReturnType && !RetValExp->isTypeDependent()) {
4086 // we have a non-void function with an expression, continue checking
4087 InitializedEntity Entity = InitializedEntity::InitializeResult(
4088 ReturnLoc, RetType, NRVOCandidate != nullptr);
4089 ExprResult Res = PerformMoveOrCopyInitialization(
4090 Entity, NRInfo, RetValExp, SupressSimplerImplicitMoves);
4091 if (Res.isInvalid()) {
4092 // FIXME: Clean up temporaries here anyway?
4093 return StmtError();
4094 }
4095 RetValExp = Res.getAs<Expr>();
4096
4097 // If we have a related result type, we need to implicitly
4098 // convert back to the formal result type. We can't pretend to
4099 // initialize the result again --- we might end double-retaining
4100 // --- so instead we initialize a notional temporary.
4101 if (!RelatedRetType.isNull()) {
4102 Entity = InitializedEntity::InitializeRelatedResult(getCurMethodDecl(),
4103 FnRetType);
4104 Res = PerformCopyInitialization(Entity, ReturnLoc, RetValExp);
4105 if (Res.isInvalid()) {
4106 // FIXME: Clean up temporaries here anyway?
4107 return StmtError();
4108 }
4109 RetValExp = Res.getAs<Expr>();
4110 }
4111
4112 CheckReturnValExpr(RetValExp, FnRetType, ReturnLoc, isObjCMethod, Attrs,
4113 getCurFunctionDecl());
4114 }
4115
4116 if (RetValExp) {
4117 ExprResult ER =
4118 ActOnFinishFullExpr(RetValExp, ReturnLoc, /*DiscardedValue*/ false);
4119 if (ER.isInvalid())
4120 return StmtError();
4121 RetValExp = ER.get();
4122 }
4123 Result = ReturnStmt::Create(Context, ReturnLoc, RetValExp, NRVOCandidate);
4124 }
4125
4126 // If we need to check for the named return value optimization, save the
4127 // return statement in our scope for later processing.
4128 if (Result->getNRVOCandidate())
4129 FunctionScopes.back()->Returns.push_back(Result);
4130
4131 if (FunctionScopes.back()->FirstReturnLoc.isInvalid())
4132 FunctionScopes.back()->FirstReturnLoc = ReturnLoc;
4133
4134 return Result;
4135}
4136
4137StmtResult
4138Sema::ActOnObjCAtCatchStmt(SourceLocation AtLoc,
4139 SourceLocation RParen, Decl *Parm,
4140 Stmt *Body) {
4141 VarDecl *Var = cast_or_null<VarDecl>(Parm);
4142 if (Var && Var->isInvalidDecl())
4143 return StmtError();
4144
4145 return new (Context) ObjCAtCatchStmt(AtLoc, RParen, Var, Body);
4146}
4147
4148StmtResult
4149Sema::ActOnObjCAtFinallyStmt(SourceLocation AtLoc, Stmt *Body) {
4150 return new (Context) ObjCAtFinallyStmt(AtLoc, Body);
4151}
4152
4153StmtResult
4154Sema::ActOnObjCAtTryStmt(SourceLocation AtLoc, Stmt *Try,
4155 MultiStmtArg CatchStmts, Stmt *Finally) {
4156 if (!getLangOpts().ObjCExceptions)
4157 Diag(AtLoc, diag::err_objc_exceptions_disabled) << "@try";
4158
4159 setFunctionHasBranchProtectedScope();
4160 unsigned NumCatchStmts = CatchStmts.size();
4161 return ObjCAtTryStmt::Create(Context, AtLoc, Try, CatchStmts.data(),
4162 NumCatchStmts, Finally);
4163}
4164
4165StmtResult Sema::BuildObjCAtThrowStmt(SourceLocation AtLoc, Expr *Throw) {
4166 if (Throw) {
4167 ExprResult Result = DefaultLvalueConversion(Throw);
4168 if (Result.isInvalid())
4169 return StmtError();
4170
4171 Result = ActOnFinishFullExpr(Result.get(), /*DiscardedValue*/ false);
4172 if (Result.isInvalid())
4173 return StmtError();
4174 Throw = Result.get();
4175
4176 QualType ThrowType = Throw->getType();
4177 // Make sure the expression type is an ObjC pointer or "void *".
4178 if (!ThrowType->isDependentType() &&
4179 !ThrowType->isObjCObjectPointerType()) {
4180 const PointerType *PT = ThrowType->getAs<PointerType>();
4181 if (!PT || !PT->getPointeeType()->isVoidType())
4182 return StmtError(Diag(AtLoc, diag::err_objc_throw_expects_object)
4183 << Throw->getType() << Throw->getSourceRange());
4184 }
4185 }
4186
4187 return new (Context) ObjCAtThrowStmt(AtLoc, Throw);
4188}
4189
4190StmtResult
4191Sema::ActOnObjCAtThrowStmt(SourceLocation AtLoc, Expr *Throw,
4192 Scope *CurScope) {
4193 if (!getLangOpts().ObjCExceptions)
4194 Diag(AtLoc, diag::err_objc_exceptions_disabled) << "@throw";
4195
4196 if (!Throw) {
4197 // @throw without an expression designates a rethrow (which must occur
4198 // in the context of an @catch clause).
4199 Scope *AtCatchParent = CurScope;
4200 while (AtCatchParent && !AtCatchParent->isAtCatchScope())
4201 AtCatchParent = AtCatchParent->getParent();
4202 if (!AtCatchParent)
4203 return StmtError(Diag(AtLoc, diag::err_rethrow_used_outside_catch));
4204 }
4205 return BuildObjCAtThrowStmt(AtLoc, Throw);
4206}
4207
4208ExprResult
4209Sema::ActOnObjCAtSynchronizedOperand(SourceLocation atLoc, Expr *operand) {
4210 ExprResult result = DefaultLvalueConversion(operand);
4211 if (result.isInvalid())
4212 return ExprError();
4213 operand = result.get();
4214
4215 // Make sure the expression type is an ObjC pointer or "void *".
4216 QualType type = operand->getType();
4217 if (!type->isDependentType() &&
4218 !type->isObjCObjectPointerType()) {
4219 const PointerType *pointerType = type->getAs<PointerType>();
4220 if (!pointerType || !pointerType->getPointeeType()->isVoidType()) {
4221 if (getLangOpts().CPlusPlus) {
4222 if (RequireCompleteType(atLoc, type,
4223 diag::err_incomplete_receiver_type))
4224 return Diag(atLoc, diag::err_objc_synchronized_expects_object)
4225 << type << operand->getSourceRange();
4226
4227 ExprResult result = PerformContextuallyConvertToObjCPointer(operand);
4228 if (result.isInvalid())
4229 return ExprError();
4230 if (!result.isUsable())
4231 return Diag(atLoc, diag::err_objc_synchronized_expects_object)
4232 << type << operand->getSourceRange();
4233
4234 operand = result.get();
4235 } else {
4236 return Diag(atLoc, diag::err_objc_synchronized_expects_object)
4237 << type << operand->getSourceRange();
4238 }
4239 }
4240 }
4241
4242 // The operand to @synchronized is a full-expression.
4243 return ActOnFinishFullExpr(operand, /*DiscardedValue*/ false);
4244}
4245
4246StmtResult
4247Sema::ActOnObjCAtSynchronizedStmt(SourceLocation AtLoc, Expr *SyncExpr,
4248 Stmt *SyncBody) {
4249 // We can't jump into or indirect-jump out of a @synchronized block.
4250 setFunctionHasBranchProtectedScope();
4251 return new (Context) ObjCAtSynchronizedStmt(AtLoc, SyncExpr, SyncBody);
4252}
4253
4254/// ActOnCXXCatchBlock - Takes an exception declaration and a handler block
4255/// and creates a proper catch handler from them.
4256StmtResult
4257Sema::ActOnCXXCatchBlock(SourceLocation CatchLoc, Decl *ExDecl,
4258 Stmt *HandlerBlock) {
4259 // There's nothing to test that ActOnExceptionDecl didn't already test.
4260 return new (Context)
4261 CXXCatchStmt(CatchLoc, cast_or_null<VarDecl>(ExDecl), HandlerBlock);
4262}
4263
4264StmtResult
4265Sema::ActOnObjCAutoreleasePoolStmt(SourceLocation AtLoc, Stmt *Body) {
4266 setFunctionHasBranchProtectedScope();
4267 return new (Context) ObjCAutoreleasePoolStmt(AtLoc, Body);
4268}
4269
4270namespace {
4271class CatchHandlerType {
4272 QualType QT;
4273 unsigned IsPointer : 1;
4274
4275 // This is a special constructor to be used only with DenseMapInfo's
4276 // getEmptyKey() and getTombstoneKey() functions.
4277 friend struct llvm::DenseMapInfo<CatchHandlerType>;
4278 enum Unique { ForDenseMap };
4279 CatchHandlerType(QualType QT, Unique) : QT(QT), IsPointer(false) {}
4280
4281public:
4282 /// Used when creating a CatchHandlerType from a handler type; will determine
4283 /// whether the type is a pointer or reference and will strip off the top
4284 /// level pointer and cv-qualifiers.
4285 CatchHandlerType(QualType Q) : QT(Q), IsPointer(false) {
4286 if (QT->isPointerType())
4287 IsPointer = true;
4288
4289 if (IsPointer || QT->isReferenceType())
4290 QT = QT->getPointeeType();
4291 QT = QT.getUnqualifiedType();
4292 }
4293
4294 /// Used when creating a CatchHandlerType from a base class type; pretends the
4295 /// type passed in had the pointer qualifier, does not need to get an
4296 /// unqualified type.
4297 CatchHandlerType(QualType QT, bool IsPointer)
4298 : QT(QT), IsPointer(IsPointer) {}
4299
4300 QualType underlying() const { return QT; }
4301 bool isPointer() const { return IsPointer; }
4302
4303 friend bool operator==(const CatchHandlerType &LHS,
4304 const CatchHandlerType &RHS) {
4305 // If the pointer qualification does not match, we can return early.
4306 if (LHS.IsPointer != RHS.IsPointer)
4307 return false;
4308 // Otherwise, check the underlying type without cv-qualifiers.
4309 return LHS.QT == RHS.QT;
4310 }
4311};
4312} // namespace
4313
4314namespace llvm {
4315template <> struct DenseMapInfo<CatchHandlerType> {
4316 static CatchHandlerType getEmptyKey() {
4317 return CatchHandlerType(DenseMapInfo<QualType>::getEmptyKey(),
4318 CatchHandlerType::ForDenseMap);
4319 }
4320
4321 static CatchHandlerType getTombstoneKey() {
4322 return CatchHandlerType(DenseMapInfo<QualType>::getTombstoneKey(),
4323 CatchHandlerType::ForDenseMap);
4324 }
4325
4326 static unsigned getHashValue(const CatchHandlerType &Base) {
4327 return DenseMapInfo<QualType>::getHashValue(Base.underlying());
4328 }
4329
4330 static bool isEqual(const CatchHandlerType &LHS,
4331 const CatchHandlerType &RHS) {
4332 return LHS == RHS;
4333 }
4334};
4335}
4336
4337namespace {
4338class CatchTypePublicBases {
4339 ASTContext &Ctx;
4340 const llvm::DenseMap<CatchHandlerType, CXXCatchStmt *> &TypesToCheck;
4341 const bool CheckAgainstPointer;
4342
4343 CXXCatchStmt *FoundHandler;
4344 CanQualType FoundHandlerType;
4345
4346public:
4347 CatchTypePublicBases(
4348 ASTContext &Ctx,
4349 const llvm::DenseMap<CatchHandlerType, CXXCatchStmt *> &T, bool C)
4350 : Ctx(Ctx), TypesToCheck(T), CheckAgainstPointer(C),
4351 FoundHandler(nullptr) {}
4352
4353 CXXCatchStmt *getFoundHandler() const { return FoundHandler; }
4354 CanQualType getFoundHandlerType() const { return FoundHandlerType; }
4355
4356 bool operator()(const CXXBaseSpecifier *S, CXXBasePath &) {
4357 if (S->getAccessSpecifier() == AccessSpecifier::AS_public) {
4358 CatchHandlerType Check(S->getType(), CheckAgainstPointer);
4359 const auto &M = TypesToCheck;
4360 auto I = M.find(Check);
4361 if (I != M.end()) {
4362 FoundHandler = I->second;
4363 FoundHandlerType = Ctx.getCanonicalType(S->getType());
4364 return true;
4365 }
4366 }
4367 return false;
4368 }
4369};
4370}
4371
4372/// ActOnCXXTryBlock - Takes a try compound-statement and a number of
4373/// handlers and creates a try statement from them.
4374StmtResult Sema::ActOnCXXTryBlock(SourceLocation TryLoc, Stmt *TryBlock,
4375 ArrayRef<Stmt *> Handlers) {
4376 // Don't report an error if 'try' is used in system headers.
4377 if (!getLangOpts().CXXExceptions &&
4378 !getSourceManager().isInSystemHeader(TryLoc) && !getLangOpts().CUDA) {
4379 // Delay error emission for the OpenMP device code.
4380 targetDiag(TryLoc, diag::err_exceptions_disabled) << "try";
4381 }
4382
4383 // Exceptions aren't allowed in CUDA device code.
4384 if (getLangOpts().CUDA)
4385 CUDADiagIfDeviceCode(TryLoc, diag::err_cuda_device_exceptions)
4386 << "try" << CurrentCUDATarget();
4387
4388 if (getCurScope() && getCurScope()->isOpenMPSimdDirectiveScope())
4389 Diag(TryLoc, diag::err_omp_simd_region_cannot_use_stmt) << "try";
4390
4391 sema::FunctionScopeInfo *FSI = getCurFunction();
4392
4393 // C++ try is incompatible with SEH __try.
4394 if (!getLangOpts().Borland && FSI->FirstSEHTryLoc.isValid()) {
4395 Diag(TryLoc, diag::err_mixing_cxx_try_seh_try);
4396 Diag(FSI->FirstSEHTryLoc, diag::note_conflicting_try_here) << "'__try'";
4397 }
4398
4399 const unsigned NumHandlers = Handlers.size();
4400 assert(!Handlers.empty() &&(static_cast<void> (0))
4401 "The parser shouldn't call this if there are no handlers.")(static_cast<void> (0));
4402
4403 llvm::DenseMap<CatchHandlerType, CXXCatchStmt *> HandledTypes;
4404 for (unsigned i = 0; i < NumHandlers; ++i) {
4405 CXXCatchStmt *H = cast<CXXCatchStmt>(Handlers[i]);
4406
4407 // Diagnose when the handler is a catch-all handler, but it isn't the last
4408 // handler for the try block. [except.handle]p5. Also, skip exception
4409 // declarations that are invalid, since we can't usefully report on them.
4410 if (!H->getExceptionDecl()) {
4411 if (i < NumHandlers - 1)
4412 return StmtError(Diag(H->getBeginLoc(), diag::err_early_catch_all));
4413 continue;
4414 } else if (H->getExceptionDecl()->isInvalidDecl())
4415 continue;
4416
4417 // Walk the type hierarchy to diagnose when this type has already been
4418 // handled (duplication), or cannot be handled (derivation inversion). We
4419 // ignore top-level cv-qualifiers, per [except.handle]p3
4420 CatchHandlerType HandlerCHT =
4421 (QualType)Context.getCanonicalType(H->getCaughtType());
4422
4423 // We can ignore whether the type is a reference or a pointer; we need the
4424 // underlying declaration type in order to get at the underlying record
4425 // decl, if there is one.
4426 QualType Underlying = HandlerCHT.underlying();
4427 if (auto *RD = Underlying->getAsCXXRecordDecl()) {
4428 if (!RD->hasDefinition())
4429 continue;
4430 // Check that none of the public, unambiguous base classes are in the
4431 // map ([except.handle]p1). Give the base classes the same pointer
4432 // qualification as the original type we are basing off of. This allows
4433 // comparison against the handler type using the same top-level pointer
4434 // as the original type.
4435 CXXBasePaths Paths;
4436 Paths.setOrigin(RD);
4437 CatchTypePublicBases CTPB(Context, HandledTypes, HandlerCHT.isPointer());
4438 if (RD->lookupInBases(CTPB, Paths)) {
4439 const CXXCatchStmt *Problem = CTPB.getFoundHandler();
4440 if (!Paths.isAmbiguous(CTPB.getFoundHandlerType())) {
4441 Diag(H->getExceptionDecl()->getTypeSpecStartLoc(),
4442 diag::warn_exception_caught_by_earlier_handler)
4443 << H->getCaughtType();
4444 Diag(Problem->getExceptionDecl()->getTypeSpecStartLoc(),
4445 diag::note_previous_exception_handler)
4446 << Problem->getCaughtType();
4447 }
4448 }
4449 }
4450
4451 // Add the type the list of ones we have handled; diagnose if we've already
4452 // handled it.
4453 auto R = HandledTypes.insert(std::make_pair(H->getCaughtType(), H));
4454 if (!R.second) {
4455 const CXXCatchStmt *Problem = R.first->second;
4456 Diag(H->getExceptionDecl()->getTypeSpecStartLoc(),
4457 diag::warn_exception_caught_by_earlier_handler)
4458 << H->getCaughtType();
4459 Diag(Problem->getExceptionDecl()->getTypeSpecStartLoc(),
4460 diag::note_previous_exception_handler)
4461 << Problem->getCaughtType();
4462 }
4463 }
4464
4465 FSI->setHasCXXTry(TryLoc);
4466
4467 return CXXTryStmt::Create(Context, TryLoc, TryBlock, Handlers);
4468}
4469
4470StmtResult Sema::ActOnSEHTryBlock(bool IsCXXTry, SourceLocation TryLoc,
4471 Stmt *TryBlock, Stmt *Handler) {
4472 assert(TryBlock && Handler)(static_cast<void> (0));
4473
4474 sema::FunctionScopeInfo *FSI = getCurFunction();
4475
4476 // SEH __try is incompatible with C++ try. Borland appears to support this,
4477 // however.
4478 if (!getLangOpts().Borland) {
4479 if (FSI->FirstCXXTryLoc.isValid()) {
4480 Diag(TryLoc, diag::err_mixing_cxx_try_seh_try);
4481 Diag(FSI->FirstCXXTryLoc, diag::note_conflicting_try_here) << "'try'";
4482 }
4483 }
4484
4485 FSI->setHasSEHTry(TryLoc);
4486
4487 // Reject __try in Obj-C methods, blocks, and captured decls, since we don't
4488 // track if they use SEH.
4489 DeclContext *DC = CurContext;
4490 while (DC && !DC->isFunctionOrMethod())
4491 DC = DC->getParent();
4492 FunctionDecl *FD = dyn_cast_or_null<FunctionDecl>(DC);
4493 if (FD)
4494 FD->setUsesSEHTry(true);
4495 else
4496 Diag(TryLoc, diag::err_seh_try_outside_functions);
4497
4498 // Reject __try on unsupported targets.
4499 if (!Context.getTargetInfo().isSEHTrySupported())
4500 Diag(TryLoc, diag::err_seh_try_unsupported);
4501
4502 return SEHTryStmt::Create(Context, IsCXXTry, TryLoc, TryBlock, Handler);
4503}
4504
4505StmtResult Sema::ActOnSEHExceptBlock(SourceLocation Loc, Expr *FilterExpr,
4506 Stmt *Block) {
4507 assert(FilterExpr && Block)(static_cast<void> (0));
4508 QualType FTy = FilterExpr->getType();
4509 if (!FTy->isIntegerType() && !FTy->isDependentType()) {
4510 return StmtError(
4511 Diag(FilterExpr->getExprLoc(), diag::err_filter_expression_integral)
4512 << FTy);
4513 }
4514 return SEHExceptStmt::Create(Context, Loc, FilterExpr, Block);
4515}
4516
4517void Sema::ActOnStartSEHFinallyBlock() {
4518 CurrentSEHFinally.push_back(CurScope);
4519}
4520
4521void Sema::ActOnAbortSEHFinallyBlock() {
4522 CurrentSEHFinally.pop_back();
4523}
4524
4525StmtResult Sema::ActOnFinishSEHFinallyBlock(SourceLocation Loc, Stmt *Block) {
4526 assert(Block)(static_cast<void> (0));
4527 CurrentSEHFinally.pop_back();
4528 return SEHFinallyStmt::Create(Context, Loc, Block);
4529}
4530
4531StmtResult
4532Sema::ActOnSEHLeaveStmt(SourceLocation Loc, Scope *CurScope) {
4533 Scope *SEHTryParent = CurScope;
4534 while (SEHTryParent && !SEHTryParent->isSEHTryScope())
4535 SEHTryParent = SEHTryParent->getParent();
4536 if (!SEHTryParent)
4537 return StmtError(Diag(Loc, diag::err_ms___leave_not_in___try));
4538 CheckJumpOutOfSEHFinally(*this, Loc, *SEHTryParent);
4539
4540 return new (Context) SEHLeaveStmt(Loc);
4541}
4542
4543StmtResult Sema::BuildMSDependentExistsStmt(SourceLocation KeywordLoc,
4544 bool IsIfExists,
4545 NestedNameSpecifierLoc QualifierLoc,
4546 DeclarationNameInfo NameInfo,
4547 Stmt *Nested)
4548{
4549 return new (Context) MSDependentExistsStmt(KeywordLoc, IsIfExists,
4550 QualifierLoc, NameInfo,
4551 cast<CompoundStmt>(Nested));
4552}
4553
4554
4555StmtResult Sema::ActOnMSDependentExistsStmt(SourceLocation KeywordLoc,
4556 bool IsIfExists,
4557 CXXScopeSpec &SS,
4558 UnqualifiedId &Name,
4559 Stmt *Nested) {
4560 return BuildMSDependentExistsStmt(KeywordLoc, IsIfExists,
4561 SS.getWithLocInContext(Context),
4562 GetNameFromUnqualifiedId(Name),
4563 Nested);
4564}
4565
4566RecordDecl*
4567Sema::CreateCapturedStmtRecordDecl(CapturedDecl *&CD, SourceLocation Loc,
4568 unsigned NumParams) {
4569 DeclContext *DC = CurContext;
4570 while (!(DC->isFunctionOrMethod() || DC->isRecord() || DC->isFileContext()))
4571 DC = DC->getParent();
4572
4573 RecordDecl *RD = nullptr;
4574 if (getLangOpts().CPlusPlus)
4575 RD = CXXRecordDecl::Create(Context, TTK_Struct, DC, Loc, Loc,
4576 /*Id=*/nullptr);
4577 else
4578 RD = RecordDecl::Create(Context, TTK_Struct, DC, Loc, Loc, /*Id=*/nullptr);
4579
4580 RD->setCapturedRecord();
4581 DC->addDecl(RD);
4582 RD->setImplicit();
4583 RD->startDefinition();
4584
4585 assert(NumParams > 0 && "CapturedStmt requires context parameter")(static_cast<void> (0));
4586 CD = CapturedDecl::Create(Context, CurContext, NumParams);
4587 DC->addDecl(CD);
4588 return RD;
4589}
4590
4591static bool
4592buildCapturedStmtCaptureList(Sema &S, CapturedRegionScopeInfo *RSI,
4593 SmallVectorImpl<CapturedStmt::Capture> &Captures,
4594 SmallVectorImpl<Expr *> &CaptureInits) {
4595 for (const sema::Capture &Cap : RSI->Captures) {
4596 if (Cap.isInvalid())
4597 continue;
4598
4599 // Form the initializer for the capture.
4600 ExprResult Init = S.BuildCaptureInit(Cap, Cap.getLocation(),
4601 RSI->CapRegionKind == CR_OpenMP);
4602
4603 // FIXME: Bail out now if the capture is not used and the initializer has
4604 // no side-effects.
4605
4606 // Create a field for this capture.
4607 FieldDecl *Field = S.BuildCaptureField(RSI->TheRecordDecl, Cap);
4608
4609 // Add the capture to our list of captures.
4610 if (Cap.isThisCapture()) {
4611 Captures.push_back(CapturedStmt::Capture(Cap.getLocation(),
4612 CapturedStmt::VCK_This));
4613 } else if (Cap.isVLATypeCapture()) {
4614 Captures.push_back(
4615 CapturedStmt::Capture(Cap.getLocation(), CapturedStmt::VCK_VLAType));
4616 } else {
4617 assert(Cap.isVariableCapture() && "unknown kind of capture")(static_cast<void> (0));
4618
4619 if (S.getLangOpts().OpenMP && RSI->CapRegionKind == CR_OpenMP)
4620 S.setOpenMPCaptureKind(Field, Cap.getVariable(), RSI->OpenMPLevel);
4621
4622 Captures.push_back(CapturedStmt::Capture(Cap.getLocation(),
4623 Cap.isReferenceCapture()
4624 ? CapturedStmt::VCK_ByRef
4625 : CapturedStmt::VCK_ByCopy,
4626 Cap.getVariable()));
4627 }
4628 CaptureInits.push_back(Init.get());
4629 }
4630 return false;
4631}
4632
4633void Sema::ActOnCapturedRegionStart(SourceLocation Loc, Scope *CurScope,
4634 CapturedRegionKind Kind,
4635 unsigned NumParams) {
4636 CapturedDecl *CD = nullptr;
4637 RecordDecl *RD = CreateCapturedStmtRecordDecl(CD, Loc, NumParams);
4638
4639 // Build the context parameter
4640 DeclContext *DC = CapturedDecl::castToDeclContext(CD);
4641 IdentifierInfo *ParamName = &Context.Idents.get("__context");
4642 QualType ParamType = Context.getPointerType(Context.getTagDeclType(RD));
4643 auto *Param =
4644 ImplicitParamDecl::Create(Context, DC, Loc, ParamName, ParamType,
4645 ImplicitParamDecl::CapturedContext);
4646 DC->addDecl(Param);
4647
4648 CD->setContextParam(0, Param);
4649
4650 // Enter the capturing scope for this captured region.
4651 PushCapturedRegionScope(CurScope, CD, RD, Kind);
4652
4653 if (CurScope)
4654 PushDeclContext(CurScope, CD);
4655 else
4656 CurContext = CD;
4657
4658 PushExpressionEvaluationContext(
4659 ExpressionEvaluationContext::PotentiallyEvaluated);
4660}
4661
4662void Sema::ActOnCapturedRegionStart(SourceLocation Loc, Scope *CurScope,
4663 CapturedRegionKind Kind,
4664 ArrayRef<CapturedParamNameType> Params,
4665 unsigned OpenMPCaptureLevel) {
4666 CapturedDecl *CD = nullptr;
4667 RecordDecl *RD = CreateCapturedStmtRecordDecl(CD, Loc, Params.size());
4668
4669 // Build the context parameter
4670 DeclContext *DC = CapturedDecl::castToDeclContext(CD);
4671 bool ContextIsFound = false;
4672 unsigned ParamNum = 0;
4673 for (ArrayRef<CapturedParamNameType>::iterator I = Params.begin(),
4674 E = Params.end();
4675 I != E; ++I, ++ParamNum) {
4676 if (I->second.isNull()) {
4677 assert(!ContextIsFound &&(static_cast<void> (0))
4678 "null type has been found already for '__context' parameter")(static_cast<void> (0));
4679 IdentifierInfo *ParamName = &Context.Idents.get("__context");
4680 QualType ParamType = Context.getPointerType(Context.getTagDeclType(RD))
4681 .withConst()
4682 .withRestrict();
4683 auto *Param =
4684 ImplicitParamDecl::Create(Context, DC, Loc, ParamName, ParamType,
4685 ImplicitParamDecl::CapturedContext);
4686 DC->addDecl(Param);
4687 CD->setContextParam(ParamNum, Param);
4688 ContextIsFound = true;
4689 } else {
4690 IdentifierInfo *ParamName = &Context.Idents.get(I->first);
4691 auto *Param =
4692 ImplicitParamDecl::Create(Context, DC, Loc, ParamName, I->second,
4693 ImplicitParamDecl::CapturedContext);
4694 DC->addDecl(Param);
4695 CD->setParam(ParamNum, Param);
4696 }
4697 }
4698 assert(ContextIsFound && "no null type for '__context' parameter")(static_cast<void> (0));
4699 if (!ContextIsFound) {
4700 // Add __context implicitly if it is not specified.
4701 IdentifierInfo *ParamName = &Context.Idents.get("__context");
4702 QualType ParamType = Context.getPointerType(Context.getTagDeclType(RD));
4703 auto *Param =
4704 ImplicitParamDecl::Create(Context, DC, Loc, ParamName, ParamType,
4705 ImplicitParamDecl::CapturedContext);
4706 DC->addDecl(Param);
4707 CD->setContextParam(ParamNum, Param);
4708 }
4709 // Enter the capturing scope for this captured region.
4710 PushCapturedRegionScope(CurScope, CD, RD, Kind, OpenMPCaptureLevel);
4711
4712 if (CurScope)
4713 PushDeclContext(CurScope, CD);
4714 else
4715 CurContext = CD;
4716
4717 PushExpressionEvaluationContext(
4718 ExpressionEvaluationContext::PotentiallyEvaluated);
4719}
4720
4721void Sema::ActOnCapturedRegionError() {
4722 DiscardCleanupsInEvaluationContext();
4723 PopExpressionEvaluationContext();
4724 PopDeclContext();
4725 PoppedFunctionScopePtr ScopeRAII = PopFunctionScopeInfo();
4726 CapturedRegionScopeInfo *RSI = cast<CapturedRegionScopeInfo>(ScopeRAII.get());
4727
4728 RecordDecl *Record = RSI->TheRecordDecl;
4729 Record->setInvalidDecl();
4730
4731 SmallVector<Decl*, 4> Fields(Record->fields());
4732 ActOnFields(/*Scope=*/nullptr, Record->getLocation(), Record, Fields,
4733 SourceLocation(), SourceLocation(), ParsedAttributesView());
4734}
4735
4736StmtResult Sema::ActOnCapturedRegionEnd(Stmt *S) {
4737 // Leave the captured scope before we start creating captures in the
4738 // enclosing scope.
4739 DiscardCleanupsInEvaluationContext();
4740 PopExpressionEvaluationContext();
4741 PopDeclContext();
4742 PoppedFunctionScopePtr ScopeRAII = PopFunctionScopeInfo();
4743 CapturedRegionScopeInfo *RSI = cast<CapturedRegionScopeInfo>(ScopeRAII.get());
4744
4745 SmallVector<CapturedStmt::Capture, 4> Captures;
4746 SmallVector<Expr *, 4> CaptureInits;
4747 if (buildCapturedStmtCaptureList(*this, RSI, Captures, CaptureInits))
4748 return StmtError();
4749
4750 CapturedDecl *CD = RSI->TheCapturedDecl;
4751 RecordDecl *RD = RSI->TheRecordDecl;
4752
4753 CapturedStmt *Res = CapturedStmt::Create(
4754 getASTContext(), S, static_cast<CapturedRegionKind>(RSI->CapRegionKind),
4755 Captures, CaptureInits, CD, RD);
4756
4757 CD->setBody(Res->getCapturedStmt());
4758 RD->completeDefinition();
4759
4760 return Res;
4761}