| File: | clang/lib/AST/ExprConstant.cpp |
| Warning: | line 9954, column 3 Called C++ object pointer is null |
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| 1 | //===--- ExprConstant.cpp - Expression Constant Evaluator -----------------===// |
| 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 the Expr constant evaluator. |
| 10 | // |
| 11 | // Constant expression evaluation produces four main results: |
| 12 | // |
| 13 | // * A success/failure flag indicating whether constant folding was successful. |
| 14 | // This is the 'bool' return value used by most of the code in this file. A |
| 15 | // 'false' return value indicates that constant folding has failed, and any |
| 16 | // appropriate diagnostic has already been produced. |
| 17 | // |
| 18 | // * An evaluated result, valid only if constant folding has not failed. |
| 19 | // |
| 20 | // * A flag indicating if evaluation encountered (unevaluated) side-effects. |
| 21 | // These arise in cases such as (sideEffect(), 0) and (sideEffect() || 1), |
| 22 | // where it is possible to determine the evaluated result regardless. |
| 23 | // |
| 24 | // * A set of notes indicating why the evaluation was not a constant expression |
| 25 | // (under the C++11 / C++1y rules only, at the moment), or, if folding failed |
| 26 | // too, why the expression could not be folded. |
| 27 | // |
| 28 | // If we are checking for a potential constant expression, failure to constant |
| 29 | // fold a potential constant sub-expression will be indicated by a 'false' |
| 30 | // return value (the expression could not be folded) and no diagnostic (the |
| 31 | // expression is not necessarily non-constant). |
| 32 | // |
| 33 | //===----------------------------------------------------------------------===// |
| 34 | |
| 35 | #include "Interp/Context.h" |
| 36 | #include "Interp/Frame.h" |
| 37 | #include "Interp/State.h" |
| 38 | #include "clang/AST/APValue.h" |
| 39 | #include "clang/AST/ASTContext.h" |
| 40 | #include "clang/AST/ASTDiagnostic.h" |
| 41 | #include "clang/AST/ASTLambda.h" |
| 42 | #include "clang/AST/Attr.h" |
| 43 | #include "clang/AST/CXXInheritance.h" |
| 44 | #include "clang/AST/CharUnits.h" |
| 45 | #include "clang/AST/CurrentSourceLocExprScope.h" |
| 46 | #include "clang/AST/Expr.h" |
| 47 | #include "clang/AST/OSLog.h" |
| 48 | #include "clang/AST/OptionalDiagnostic.h" |
| 49 | #include "clang/AST/RecordLayout.h" |
| 50 | #include "clang/AST/StmtVisitor.h" |
| 51 | #include "clang/AST/TypeLoc.h" |
| 52 | #include "clang/Basic/Builtins.h" |
| 53 | #include "clang/Basic/TargetInfo.h" |
| 54 | #include "llvm/ADT/APFixedPoint.h" |
| 55 | #include "llvm/ADT/Optional.h" |
| 56 | #include "llvm/ADT/SmallBitVector.h" |
| 57 | #include "llvm/Support/Debug.h" |
| 58 | #include "llvm/Support/SaveAndRestore.h" |
| 59 | #include "llvm/Support/raw_ostream.h" |
| 60 | #include <cstring> |
| 61 | #include <functional> |
| 62 | |
| 63 | #define DEBUG_TYPE"exprconstant" "exprconstant" |
| 64 | |
| 65 | using namespace clang; |
| 66 | using llvm::APFixedPoint; |
| 67 | using llvm::APInt; |
| 68 | using llvm::APSInt; |
| 69 | using llvm::APFloat; |
| 70 | using llvm::FixedPointSemantics; |
| 71 | using llvm::Optional; |
| 72 | |
| 73 | namespace { |
| 74 | struct LValue; |
| 75 | class CallStackFrame; |
| 76 | class EvalInfo; |
| 77 | |
| 78 | using SourceLocExprScopeGuard = |
| 79 | CurrentSourceLocExprScope::SourceLocExprScopeGuard; |
| 80 | |
| 81 | static QualType getType(APValue::LValueBase B) { |
| 82 | if (!B) return QualType(); |
| 83 | if (const ValueDecl *D = B.dyn_cast<const ValueDecl*>()) { |
| 84 | // FIXME: It's unclear where we're supposed to take the type from, and |
| 85 | // this actually matters for arrays of unknown bound. Eg: |
| 86 | // |
| 87 | // extern int arr[]; void f() { extern int arr[3]; }; |
| 88 | // constexpr int *p = &arr[1]; // valid? |
| 89 | // |
| 90 | // For now, we take the array bound from the most recent declaration. |
| 91 | for (auto *Redecl = cast<ValueDecl>(D->getMostRecentDecl()); Redecl; |
| 92 | Redecl = cast_or_null<ValueDecl>(Redecl->getPreviousDecl())) { |
| 93 | QualType T = Redecl->getType(); |
| 94 | if (!T->isIncompleteArrayType()) |
| 95 | return T; |
| 96 | } |
| 97 | return D->getType(); |
| 98 | } |
| 99 | |
| 100 | if (B.is<TypeInfoLValue>()) |
| 101 | return B.getTypeInfoType(); |
| 102 | |
| 103 | if (B.is<DynamicAllocLValue>()) |
| 104 | return B.getDynamicAllocType(); |
| 105 | |
| 106 | const Expr *Base = B.get<const Expr*>(); |
| 107 | |
| 108 | // For a materialized temporary, the type of the temporary we materialized |
| 109 | // may not be the type of the expression. |
| 110 | if (const MaterializeTemporaryExpr *MTE = |
| 111 | dyn_cast<MaterializeTemporaryExpr>(Base)) { |
| 112 | SmallVector<const Expr *, 2> CommaLHSs; |
| 113 | SmallVector<SubobjectAdjustment, 2> Adjustments; |
| 114 | const Expr *Temp = MTE->getSubExpr(); |
| 115 | const Expr *Inner = Temp->skipRValueSubobjectAdjustments(CommaLHSs, |
| 116 | Adjustments); |
| 117 | // Keep any cv-qualifiers from the reference if we generated a temporary |
| 118 | // for it directly. Otherwise use the type after adjustment. |
| 119 | if (!Adjustments.empty()) |
| 120 | return Inner->getType(); |
| 121 | } |
| 122 | |
| 123 | return Base->getType(); |
| 124 | } |
| 125 | |
| 126 | /// Get an LValue path entry, which is known to not be an array index, as a |
| 127 | /// field declaration. |
| 128 | static const FieldDecl *getAsField(APValue::LValuePathEntry E) { |
| 129 | return dyn_cast_or_null<FieldDecl>(E.getAsBaseOrMember().getPointer()); |
| 130 | } |
| 131 | /// Get an LValue path entry, which is known to not be an array index, as a |
| 132 | /// base class declaration. |
| 133 | static const CXXRecordDecl *getAsBaseClass(APValue::LValuePathEntry E) { |
| 134 | return dyn_cast_or_null<CXXRecordDecl>(E.getAsBaseOrMember().getPointer()); |
| 135 | } |
| 136 | /// Determine whether this LValue path entry for a base class names a virtual |
| 137 | /// base class. |
| 138 | static bool isVirtualBaseClass(APValue::LValuePathEntry E) { |
| 139 | return E.getAsBaseOrMember().getInt(); |
| 140 | } |
| 141 | |
| 142 | /// Given an expression, determine the type used to store the result of |
| 143 | /// evaluating that expression. |
| 144 | static QualType getStorageType(const ASTContext &Ctx, const Expr *E) { |
| 145 | if (E->isRValue()) |
| 146 | return E->getType(); |
| 147 | return Ctx.getLValueReferenceType(E->getType()); |
| 148 | } |
| 149 | |
| 150 | /// Given a CallExpr, try to get the alloc_size attribute. May return null. |
| 151 | static const AllocSizeAttr *getAllocSizeAttr(const CallExpr *CE) { |
| 152 | const FunctionDecl *Callee = CE->getDirectCallee(); |
| 153 | return Callee ? Callee->getAttr<AllocSizeAttr>() : nullptr; |
| 154 | } |
| 155 | |
| 156 | /// Attempts to unwrap a CallExpr (with an alloc_size attribute) from an Expr. |
| 157 | /// This will look through a single cast. |
| 158 | /// |
| 159 | /// Returns null if we couldn't unwrap a function with alloc_size. |
| 160 | static const CallExpr *tryUnwrapAllocSizeCall(const Expr *E) { |
| 161 | if (!E->getType()->isPointerType()) |
| 162 | return nullptr; |
| 163 | |
| 164 | E = E->IgnoreParens(); |
| 165 | // If we're doing a variable assignment from e.g. malloc(N), there will |
| 166 | // probably be a cast of some kind. In exotic cases, we might also see a |
| 167 | // top-level ExprWithCleanups. Ignore them either way. |
| 168 | if (const auto *FE = dyn_cast<FullExpr>(E)) |
| 169 | E = FE->getSubExpr()->IgnoreParens(); |
| 170 | |
| 171 | if (const auto *Cast = dyn_cast<CastExpr>(E)) |
| 172 | E = Cast->getSubExpr()->IgnoreParens(); |
| 173 | |
| 174 | if (const auto *CE = dyn_cast<CallExpr>(E)) |
| 175 | return getAllocSizeAttr(CE) ? CE : nullptr; |
| 176 | return nullptr; |
| 177 | } |
| 178 | |
| 179 | /// Determines whether or not the given Base contains a call to a function |
| 180 | /// with the alloc_size attribute. |
| 181 | static bool isBaseAnAllocSizeCall(APValue::LValueBase Base) { |
| 182 | const auto *E = Base.dyn_cast<const Expr *>(); |
| 183 | return E && E->getType()->isPointerType() && tryUnwrapAllocSizeCall(E); |
| 184 | } |
| 185 | |
| 186 | /// The bound to claim that an array of unknown bound has. |
| 187 | /// The value in MostDerivedArraySize is undefined in this case. So, set it |
| 188 | /// to an arbitrary value that's likely to loudly break things if it's used. |
| 189 | static const uint64_t AssumedSizeForUnsizedArray = |
| 190 | std::numeric_limits<uint64_t>::max() / 2; |
| 191 | |
| 192 | /// Determines if an LValue with the given LValueBase will have an unsized |
| 193 | /// array in its designator. |
| 194 | /// Find the path length and type of the most-derived subobject in the given |
| 195 | /// path, and find the size of the containing array, if any. |
| 196 | static unsigned |
| 197 | findMostDerivedSubobject(ASTContext &Ctx, APValue::LValueBase Base, |
| 198 | ArrayRef<APValue::LValuePathEntry> Path, |
| 199 | uint64_t &ArraySize, QualType &Type, bool &IsArray, |
| 200 | bool &FirstEntryIsUnsizedArray) { |
| 201 | // This only accepts LValueBases from APValues, and APValues don't support |
| 202 | // arrays that lack size info. |
| 203 | assert(!isBaseAnAllocSizeCall(Base) &&((!isBaseAnAllocSizeCall(Base) && "Unsized arrays shouldn't appear here" ) ? static_cast<void> (0) : __assert_fail ("!isBaseAnAllocSizeCall(Base) && \"Unsized arrays shouldn't appear here\"" , "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 204, __PRETTY_FUNCTION__)) |
| 204 | "Unsized arrays shouldn't appear here")((!isBaseAnAllocSizeCall(Base) && "Unsized arrays shouldn't appear here" ) ? static_cast<void> (0) : __assert_fail ("!isBaseAnAllocSizeCall(Base) && \"Unsized arrays shouldn't appear here\"" , "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 204, __PRETTY_FUNCTION__)); |
| 205 | unsigned MostDerivedLength = 0; |
| 206 | Type = getType(Base); |
| 207 | |
| 208 | for (unsigned I = 0, N = Path.size(); I != N; ++I) { |
| 209 | if (Type->isArrayType()) { |
| 210 | const ArrayType *AT = Ctx.getAsArrayType(Type); |
| 211 | Type = AT->getElementType(); |
| 212 | MostDerivedLength = I + 1; |
| 213 | IsArray = true; |
| 214 | |
| 215 | if (auto *CAT = dyn_cast<ConstantArrayType>(AT)) { |
| 216 | ArraySize = CAT->getSize().getZExtValue(); |
| 217 | } else { |
| 218 | assert(I == 0 && "unexpected unsized array designator")((I == 0 && "unexpected unsized array designator") ? static_cast <void> (0) : __assert_fail ("I == 0 && \"unexpected unsized array designator\"" , "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 218, __PRETTY_FUNCTION__)); |
| 219 | FirstEntryIsUnsizedArray = true; |
| 220 | ArraySize = AssumedSizeForUnsizedArray; |
| 221 | } |
| 222 | } else if (Type->isAnyComplexType()) { |
| 223 | const ComplexType *CT = Type->castAs<ComplexType>(); |
| 224 | Type = CT->getElementType(); |
| 225 | ArraySize = 2; |
| 226 | MostDerivedLength = I + 1; |
| 227 | IsArray = true; |
| 228 | } else if (const FieldDecl *FD = getAsField(Path[I])) { |
| 229 | Type = FD->getType(); |
| 230 | ArraySize = 0; |
| 231 | MostDerivedLength = I + 1; |
| 232 | IsArray = false; |
| 233 | } else { |
| 234 | // Path[I] describes a base class. |
| 235 | ArraySize = 0; |
| 236 | IsArray = false; |
| 237 | } |
| 238 | } |
| 239 | return MostDerivedLength; |
| 240 | } |
| 241 | |
| 242 | /// A path from a glvalue to a subobject of that glvalue. |
| 243 | struct SubobjectDesignator { |
| 244 | /// True if the subobject was named in a manner not supported by C++11. Such |
| 245 | /// lvalues can still be folded, but they are not core constant expressions |
| 246 | /// and we cannot perform lvalue-to-rvalue conversions on them. |
| 247 | unsigned Invalid : 1; |
| 248 | |
| 249 | /// Is this a pointer one past the end of an object? |
| 250 | unsigned IsOnePastTheEnd : 1; |
| 251 | |
| 252 | /// Indicator of whether the first entry is an unsized array. |
| 253 | unsigned FirstEntryIsAnUnsizedArray : 1; |
| 254 | |
| 255 | /// Indicator of whether the most-derived object is an array element. |
| 256 | unsigned MostDerivedIsArrayElement : 1; |
| 257 | |
| 258 | /// The length of the path to the most-derived object of which this is a |
| 259 | /// subobject. |
| 260 | unsigned MostDerivedPathLength : 28; |
| 261 | |
| 262 | /// The size of the array of which the most-derived object is an element. |
| 263 | /// This will always be 0 if the most-derived object is not an array |
| 264 | /// element. 0 is not an indicator of whether or not the most-derived object |
| 265 | /// is an array, however, because 0-length arrays are allowed. |
| 266 | /// |
| 267 | /// If the current array is an unsized array, the value of this is |
| 268 | /// undefined. |
| 269 | uint64_t MostDerivedArraySize; |
| 270 | |
| 271 | /// The type of the most derived object referred to by this address. |
| 272 | QualType MostDerivedType; |
| 273 | |
| 274 | typedef APValue::LValuePathEntry PathEntry; |
| 275 | |
| 276 | /// The entries on the path from the glvalue to the designated subobject. |
| 277 | SmallVector<PathEntry, 8> Entries; |
| 278 | |
| 279 | SubobjectDesignator() : Invalid(true) {} |
| 280 | |
| 281 | explicit SubobjectDesignator(QualType T) |
| 282 | : Invalid(false), IsOnePastTheEnd(false), |
| 283 | FirstEntryIsAnUnsizedArray(false), MostDerivedIsArrayElement(false), |
| 284 | MostDerivedPathLength(0), MostDerivedArraySize(0), |
| 285 | MostDerivedType(T) {} |
| 286 | |
| 287 | SubobjectDesignator(ASTContext &Ctx, const APValue &V) |
| 288 | : Invalid(!V.isLValue() || !V.hasLValuePath()), IsOnePastTheEnd(false), |
| 289 | FirstEntryIsAnUnsizedArray(false), MostDerivedIsArrayElement(false), |
| 290 | MostDerivedPathLength(0), MostDerivedArraySize(0) { |
| 291 | assert(V.isLValue() && "Non-LValue used to make an LValue designator?")((V.isLValue() && "Non-LValue used to make an LValue designator?" ) ? static_cast<void> (0) : __assert_fail ("V.isLValue() && \"Non-LValue used to make an LValue designator?\"" , "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 291, __PRETTY_FUNCTION__)); |
| 292 | if (!Invalid) { |
| 293 | IsOnePastTheEnd = V.isLValueOnePastTheEnd(); |
| 294 | ArrayRef<PathEntry> VEntries = V.getLValuePath(); |
| 295 | Entries.insert(Entries.end(), VEntries.begin(), VEntries.end()); |
| 296 | if (V.getLValueBase()) { |
| 297 | bool IsArray = false; |
| 298 | bool FirstIsUnsizedArray = false; |
| 299 | MostDerivedPathLength = findMostDerivedSubobject( |
| 300 | Ctx, V.getLValueBase(), V.getLValuePath(), MostDerivedArraySize, |
| 301 | MostDerivedType, IsArray, FirstIsUnsizedArray); |
| 302 | MostDerivedIsArrayElement = IsArray; |
| 303 | FirstEntryIsAnUnsizedArray = FirstIsUnsizedArray; |
| 304 | } |
| 305 | } |
| 306 | } |
| 307 | |
| 308 | void truncate(ASTContext &Ctx, APValue::LValueBase Base, |
| 309 | unsigned NewLength) { |
| 310 | if (Invalid) |
| 311 | return; |
| 312 | |
| 313 | assert(Base && "cannot truncate path for null pointer")((Base && "cannot truncate path for null pointer") ? static_cast <void> (0) : __assert_fail ("Base && \"cannot truncate path for null pointer\"" , "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 313, __PRETTY_FUNCTION__)); |
| 314 | assert(NewLength <= Entries.size() && "not a truncation")((NewLength <= Entries.size() && "not a truncation" ) ? static_cast<void> (0) : __assert_fail ("NewLength <= Entries.size() && \"not a truncation\"" , "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 314, __PRETTY_FUNCTION__)); |
| 315 | |
| 316 | if (NewLength == Entries.size()) |
| 317 | return; |
| 318 | Entries.resize(NewLength); |
| 319 | |
| 320 | bool IsArray = false; |
| 321 | bool FirstIsUnsizedArray = false; |
| 322 | MostDerivedPathLength = findMostDerivedSubobject( |
| 323 | Ctx, Base, Entries, MostDerivedArraySize, MostDerivedType, IsArray, |
| 324 | FirstIsUnsizedArray); |
| 325 | MostDerivedIsArrayElement = IsArray; |
| 326 | FirstEntryIsAnUnsizedArray = FirstIsUnsizedArray; |
| 327 | } |
| 328 | |
| 329 | void setInvalid() { |
| 330 | Invalid = true; |
| 331 | Entries.clear(); |
| 332 | } |
| 333 | |
| 334 | /// Determine whether the most derived subobject is an array without a |
| 335 | /// known bound. |
| 336 | bool isMostDerivedAnUnsizedArray() const { |
| 337 | assert(!Invalid && "Calling this makes no sense on invalid designators")((!Invalid && "Calling this makes no sense on invalid designators" ) ? static_cast<void> (0) : __assert_fail ("!Invalid && \"Calling this makes no sense on invalid designators\"" , "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 337, __PRETTY_FUNCTION__)); |
| 338 | return Entries.size() == 1 && FirstEntryIsAnUnsizedArray; |
| 339 | } |
| 340 | |
| 341 | /// Determine what the most derived array's size is. Results in an assertion |
| 342 | /// failure if the most derived array lacks a size. |
| 343 | uint64_t getMostDerivedArraySize() const { |
| 344 | assert(!isMostDerivedAnUnsizedArray() && "Unsized array has no size")((!isMostDerivedAnUnsizedArray() && "Unsized array has no size" ) ? static_cast<void> (0) : __assert_fail ("!isMostDerivedAnUnsizedArray() && \"Unsized array has no size\"" , "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 344, __PRETTY_FUNCTION__)); |
| 345 | return MostDerivedArraySize; |
| 346 | } |
| 347 | |
| 348 | /// Determine whether this is a one-past-the-end pointer. |
| 349 | bool isOnePastTheEnd() const { |
| 350 | assert(!Invalid)((!Invalid) ? static_cast<void> (0) : __assert_fail ("!Invalid" , "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 350, __PRETTY_FUNCTION__)); |
| 351 | if (IsOnePastTheEnd) |
| 352 | return true; |
| 353 | if (!isMostDerivedAnUnsizedArray() && MostDerivedIsArrayElement && |
| 354 | Entries[MostDerivedPathLength - 1].getAsArrayIndex() == |
| 355 | MostDerivedArraySize) |
| 356 | return true; |
| 357 | return false; |
| 358 | } |
| 359 | |
| 360 | /// Get the range of valid index adjustments in the form |
| 361 | /// {maximum value that can be subtracted from this pointer, |
| 362 | /// maximum value that can be added to this pointer} |
| 363 | std::pair<uint64_t, uint64_t> validIndexAdjustments() { |
| 364 | if (Invalid || isMostDerivedAnUnsizedArray()) |
| 365 | return {0, 0}; |
| 366 | |
| 367 | // [expr.add]p4: For the purposes of these operators, a pointer to a |
| 368 | // nonarray object behaves the same as a pointer to the first element of |
| 369 | // an array of length one with the type of the object as its element type. |
| 370 | bool IsArray = MostDerivedPathLength == Entries.size() && |
| 371 | MostDerivedIsArrayElement; |
| 372 | uint64_t ArrayIndex = IsArray ? Entries.back().getAsArrayIndex() |
| 373 | : (uint64_t)IsOnePastTheEnd; |
| 374 | uint64_t ArraySize = |
| 375 | IsArray ? getMostDerivedArraySize() : (uint64_t)1; |
| 376 | return {ArrayIndex, ArraySize - ArrayIndex}; |
| 377 | } |
| 378 | |
| 379 | /// Check that this refers to a valid subobject. |
| 380 | bool isValidSubobject() const { |
| 381 | if (Invalid) |
| 382 | return false; |
| 383 | return !isOnePastTheEnd(); |
| 384 | } |
| 385 | /// Check that this refers to a valid subobject, and if not, produce a |
| 386 | /// relevant diagnostic and set the designator as invalid. |
| 387 | bool checkSubobject(EvalInfo &Info, const Expr *E, CheckSubobjectKind CSK); |
| 388 | |
| 389 | /// Get the type of the designated object. |
| 390 | QualType getType(ASTContext &Ctx) const { |
| 391 | assert(!Invalid && "invalid designator has no subobject type")((!Invalid && "invalid designator has no subobject type" ) ? static_cast<void> (0) : __assert_fail ("!Invalid && \"invalid designator has no subobject type\"" , "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 391, __PRETTY_FUNCTION__)); |
| 392 | return MostDerivedPathLength == Entries.size() |
| 393 | ? MostDerivedType |
| 394 | : Ctx.getRecordType(getAsBaseClass(Entries.back())); |
| 395 | } |
| 396 | |
| 397 | /// Update this designator to refer to the first element within this array. |
| 398 | void addArrayUnchecked(const ConstantArrayType *CAT) { |
| 399 | Entries.push_back(PathEntry::ArrayIndex(0)); |
| 400 | |
| 401 | // This is a most-derived object. |
| 402 | MostDerivedType = CAT->getElementType(); |
| 403 | MostDerivedIsArrayElement = true; |
| 404 | MostDerivedArraySize = CAT->getSize().getZExtValue(); |
| 405 | MostDerivedPathLength = Entries.size(); |
| 406 | } |
| 407 | /// Update this designator to refer to the first element within the array of |
| 408 | /// elements of type T. This is an array of unknown size. |
| 409 | void addUnsizedArrayUnchecked(QualType ElemTy) { |
| 410 | Entries.push_back(PathEntry::ArrayIndex(0)); |
| 411 | |
| 412 | MostDerivedType = ElemTy; |
| 413 | MostDerivedIsArrayElement = true; |
| 414 | // The value in MostDerivedArraySize is undefined in this case. So, set it |
| 415 | // to an arbitrary value that's likely to loudly break things if it's |
| 416 | // used. |
| 417 | MostDerivedArraySize = AssumedSizeForUnsizedArray; |
| 418 | MostDerivedPathLength = Entries.size(); |
| 419 | } |
| 420 | /// Update this designator to refer to the given base or member of this |
| 421 | /// object. |
| 422 | void addDeclUnchecked(const Decl *D, bool Virtual = false) { |
| 423 | Entries.push_back(APValue::BaseOrMemberType(D, Virtual)); |
| 424 | |
| 425 | // If this isn't a base class, it's a new most-derived object. |
| 426 | if (const FieldDecl *FD = dyn_cast<FieldDecl>(D)) { |
| 427 | MostDerivedType = FD->getType(); |
| 428 | MostDerivedIsArrayElement = false; |
| 429 | MostDerivedArraySize = 0; |
| 430 | MostDerivedPathLength = Entries.size(); |
| 431 | } |
| 432 | } |
| 433 | /// Update this designator to refer to the given complex component. |
| 434 | void addComplexUnchecked(QualType EltTy, bool Imag) { |
| 435 | Entries.push_back(PathEntry::ArrayIndex(Imag)); |
| 436 | |
| 437 | // This is technically a most-derived object, though in practice this |
| 438 | // is unlikely to matter. |
| 439 | MostDerivedType = EltTy; |
| 440 | MostDerivedIsArrayElement = true; |
| 441 | MostDerivedArraySize = 2; |
| 442 | MostDerivedPathLength = Entries.size(); |
| 443 | } |
| 444 | void diagnoseUnsizedArrayPointerArithmetic(EvalInfo &Info, const Expr *E); |
| 445 | void diagnosePointerArithmetic(EvalInfo &Info, const Expr *E, |
| 446 | const APSInt &N); |
| 447 | /// Add N to the address of this subobject. |
| 448 | void adjustIndex(EvalInfo &Info, const Expr *E, APSInt N) { |
| 449 | if (Invalid || !N) return; |
| 450 | uint64_t TruncatedN = N.extOrTrunc(64).getZExtValue(); |
| 451 | if (isMostDerivedAnUnsizedArray()) { |
| 452 | diagnoseUnsizedArrayPointerArithmetic(Info, E); |
| 453 | // Can't verify -- trust that the user is doing the right thing (or if |
| 454 | // not, trust that the caller will catch the bad behavior). |
| 455 | // FIXME: Should we reject if this overflows, at least? |
| 456 | Entries.back() = PathEntry::ArrayIndex( |
| 457 | Entries.back().getAsArrayIndex() + TruncatedN); |
| 458 | return; |
| 459 | } |
| 460 | |
| 461 | // [expr.add]p4: For the purposes of these operators, a pointer to a |
| 462 | // nonarray object behaves the same as a pointer to the first element of |
| 463 | // an array of length one with the type of the object as its element type. |
| 464 | bool IsArray = MostDerivedPathLength == Entries.size() && |
| 465 | MostDerivedIsArrayElement; |
| 466 | uint64_t ArrayIndex = IsArray ? Entries.back().getAsArrayIndex() |
| 467 | : (uint64_t)IsOnePastTheEnd; |
| 468 | uint64_t ArraySize = |
| 469 | IsArray ? getMostDerivedArraySize() : (uint64_t)1; |
| 470 | |
| 471 | if (N < -(int64_t)ArrayIndex || N > ArraySize - ArrayIndex) { |
| 472 | // Calculate the actual index in a wide enough type, so we can include |
| 473 | // it in the note. |
| 474 | N = N.extend(std::max<unsigned>(N.getBitWidth() + 1, 65)); |
| 475 | (llvm::APInt&)N += ArrayIndex; |
| 476 | assert(N.ugt(ArraySize) && "bounds check failed for in-bounds index")((N.ugt(ArraySize) && "bounds check failed for in-bounds index" ) ? static_cast<void> (0) : __assert_fail ("N.ugt(ArraySize) && \"bounds check failed for in-bounds index\"" , "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 476, __PRETTY_FUNCTION__)); |
| 477 | diagnosePointerArithmetic(Info, E, N); |
| 478 | setInvalid(); |
| 479 | return; |
| 480 | } |
| 481 | |
| 482 | ArrayIndex += TruncatedN; |
| 483 | assert(ArrayIndex <= ArraySize &&((ArrayIndex <= ArraySize && "bounds check succeeded for out-of-bounds index" ) ? static_cast<void> (0) : __assert_fail ("ArrayIndex <= ArraySize && \"bounds check succeeded for out-of-bounds index\"" , "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 484, __PRETTY_FUNCTION__)) |
| 484 | "bounds check succeeded for out-of-bounds index")((ArrayIndex <= ArraySize && "bounds check succeeded for out-of-bounds index" ) ? static_cast<void> (0) : __assert_fail ("ArrayIndex <= ArraySize && \"bounds check succeeded for out-of-bounds index\"" , "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 484, __PRETTY_FUNCTION__)); |
| 485 | |
| 486 | if (IsArray) |
| 487 | Entries.back() = PathEntry::ArrayIndex(ArrayIndex); |
| 488 | else |
| 489 | IsOnePastTheEnd = (ArrayIndex != 0); |
| 490 | } |
| 491 | }; |
| 492 | |
| 493 | /// A stack frame in the constexpr call stack. |
| 494 | class CallStackFrame : public interp::Frame { |
| 495 | public: |
| 496 | EvalInfo &Info; |
| 497 | |
| 498 | /// Parent - The caller of this stack frame. |
| 499 | CallStackFrame *Caller; |
| 500 | |
| 501 | /// Callee - The function which was called. |
| 502 | const FunctionDecl *Callee; |
| 503 | |
| 504 | /// This - The binding for the this pointer in this call, if any. |
| 505 | const LValue *This; |
| 506 | |
| 507 | /// Arguments - Parameter bindings for this function call, indexed by |
| 508 | /// parameters' function scope indices. |
| 509 | APValue *Arguments; |
| 510 | |
| 511 | /// Source location information about the default argument or default |
| 512 | /// initializer expression we're evaluating, if any. |
| 513 | CurrentSourceLocExprScope CurSourceLocExprScope; |
| 514 | |
| 515 | // Note that we intentionally use std::map here so that references to |
| 516 | // values are stable. |
| 517 | typedef std::pair<const void *, unsigned> MapKeyTy; |
| 518 | typedef std::map<MapKeyTy, APValue> MapTy; |
| 519 | /// Temporaries - Temporary lvalues materialized within this stack frame. |
| 520 | MapTy Temporaries; |
| 521 | |
| 522 | /// CallLoc - The location of the call expression for this call. |
| 523 | SourceLocation CallLoc; |
| 524 | |
| 525 | /// Index - The call index of this call. |
| 526 | unsigned Index; |
| 527 | |
| 528 | /// The stack of integers for tracking version numbers for temporaries. |
| 529 | SmallVector<unsigned, 2> TempVersionStack = {1}; |
| 530 | unsigned CurTempVersion = TempVersionStack.back(); |
| 531 | |
| 532 | unsigned getTempVersion() const { return TempVersionStack.back(); } |
| 533 | |
| 534 | void pushTempVersion() { |
| 535 | TempVersionStack.push_back(++CurTempVersion); |
| 536 | } |
| 537 | |
| 538 | void popTempVersion() { |
| 539 | TempVersionStack.pop_back(); |
| 540 | } |
| 541 | |
| 542 | // FIXME: Adding this to every 'CallStackFrame' may have a nontrivial impact |
| 543 | // on the overall stack usage of deeply-recursing constexpr evaluations. |
| 544 | // (We should cache this map rather than recomputing it repeatedly.) |
| 545 | // But let's try this and see how it goes; we can look into caching the map |
| 546 | // as a later change. |
| 547 | |
| 548 | /// LambdaCaptureFields - Mapping from captured variables/this to |
| 549 | /// corresponding data members in the closure class. |
| 550 | llvm::DenseMap<const VarDecl *, FieldDecl *> LambdaCaptureFields; |
| 551 | FieldDecl *LambdaThisCaptureField; |
| 552 | |
| 553 | CallStackFrame(EvalInfo &Info, SourceLocation CallLoc, |
| 554 | const FunctionDecl *Callee, const LValue *This, |
| 555 | APValue *Arguments); |
| 556 | ~CallStackFrame(); |
| 557 | |
| 558 | // Return the temporary for Key whose version number is Version. |
| 559 | APValue *getTemporary(const void *Key, unsigned Version) { |
| 560 | MapKeyTy KV(Key, Version); |
| 561 | auto LB = Temporaries.lower_bound(KV); |
| 562 | if (LB != Temporaries.end() && LB->first == KV) |
| 563 | return &LB->second; |
| 564 | // Pair (Key,Version) wasn't found in the map. Check that no elements |
| 565 | // in the map have 'Key' as their key. |
| 566 | assert((LB == Temporaries.end() || LB->first.first != Key) &&(((LB == Temporaries.end() || LB->first.first != Key) && (LB == Temporaries.begin() || std::prev(LB)->first.first != Key) && "Element with key 'Key' found in map") ? static_cast <void> (0) : __assert_fail ("(LB == Temporaries.end() || LB->first.first != Key) && (LB == Temporaries.begin() || std::prev(LB)->first.first != Key) && \"Element with key 'Key' found in map\"" , "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 568, __PRETTY_FUNCTION__)) |
| 567 | (LB == Temporaries.begin() || std::prev(LB)->first.first != Key) &&(((LB == Temporaries.end() || LB->first.first != Key) && (LB == Temporaries.begin() || std::prev(LB)->first.first != Key) && "Element with key 'Key' found in map") ? static_cast <void> (0) : __assert_fail ("(LB == Temporaries.end() || LB->first.first != Key) && (LB == Temporaries.begin() || std::prev(LB)->first.first != Key) && \"Element with key 'Key' found in map\"" , "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 568, __PRETTY_FUNCTION__)) |
| 568 | "Element with key 'Key' found in map")(((LB == Temporaries.end() || LB->first.first != Key) && (LB == Temporaries.begin() || std::prev(LB)->first.first != Key) && "Element with key 'Key' found in map") ? static_cast <void> (0) : __assert_fail ("(LB == Temporaries.end() || LB->first.first != Key) && (LB == Temporaries.begin() || std::prev(LB)->first.first != Key) && \"Element with key 'Key' found in map\"" , "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 568, __PRETTY_FUNCTION__)); |
| 569 | return nullptr; |
| 570 | } |
| 571 | |
| 572 | // Return the current temporary for Key in the map. |
| 573 | APValue *getCurrentTemporary(const void *Key) { |
| 574 | auto UB = Temporaries.upper_bound(MapKeyTy(Key, UINT_MAX(2147483647 *2U +1U))); |
| 575 | if (UB != Temporaries.begin() && std::prev(UB)->first.first == Key) |
| 576 | return &std::prev(UB)->second; |
| 577 | return nullptr; |
| 578 | } |
| 579 | |
| 580 | // Return the version number of the current temporary for Key. |
| 581 | unsigned getCurrentTemporaryVersion(const void *Key) const { |
| 582 | auto UB = Temporaries.upper_bound(MapKeyTy(Key, UINT_MAX(2147483647 *2U +1U))); |
| 583 | if (UB != Temporaries.begin() && std::prev(UB)->first.first == Key) |
| 584 | return std::prev(UB)->first.second; |
| 585 | return 0; |
| 586 | } |
| 587 | |
| 588 | /// Allocate storage for an object of type T in this stack frame. |
| 589 | /// Populates LV with a handle to the created object. Key identifies |
| 590 | /// the temporary within the stack frame, and must not be reused without |
| 591 | /// bumping the temporary version number. |
| 592 | template<typename KeyT> |
| 593 | APValue &createTemporary(const KeyT *Key, QualType T, |
| 594 | bool IsLifetimeExtended, LValue &LV); |
| 595 | |
| 596 | void describe(llvm::raw_ostream &OS) override; |
| 597 | |
| 598 | Frame *getCaller() const override { return Caller; } |
| 599 | SourceLocation getCallLocation() const override { return CallLoc; } |
| 600 | const FunctionDecl *getCallee() const override { return Callee; } |
| 601 | |
| 602 | bool isStdFunction() const { |
| 603 | for (const DeclContext *DC = Callee; DC; DC = DC->getParent()) |
| 604 | if (DC->isStdNamespace()) |
| 605 | return true; |
| 606 | return false; |
| 607 | } |
| 608 | }; |
| 609 | |
| 610 | /// Temporarily override 'this'. |
| 611 | class ThisOverrideRAII { |
| 612 | public: |
| 613 | ThisOverrideRAII(CallStackFrame &Frame, const LValue *NewThis, bool Enable) |
| 614 | : Frame(Frame), OldThis(Frame.This) { |
| 615 | if (Enable) |
| 616 | Frame.This = NewThis; |
| 617 | } |
| 618 | ~ThisOverrideRAII() { |
| 619 | Frame.This = OldThis; |
| 620 | } |
| 621 | private: |
| 622 | CallStackFrame &Frame; |
| 623 | const LValue *OldThis; |
| 624 | }; |
| 625 | } |
| 626 | |
| 627 | static bool HandleDestruction(EvalInfo &Info, const Expr *E, |
| 628 | const LValue &This, QualType ThisType); |
| 629 | static bool HandleDestruction(EvalInfo &Info, SourceLocation Loc, |
| 630 | APValue::LValueBase LVBase, APValue &Value, |
| 631 | QualType T); |
| 632 | |
| 633 | namespace { |
| 634 | /// A cleanup, and a flag indicating whether it is lifetime-extended. |
| 635 | class Cleanup { |
| 636 | llvm::PointerIntPair<APValue*, 1, bool> Value; |
| 637 | APValue::LValueBase Base; |
| 638 | QualType T; |
| 639 | |
| 640 | public: |
| 641 | Cleanup(APValue *Val, APValue::LValueBase Base, QualType T, |
| 642 | bool IsLifetimeExtended) |
| 643 | : Value(Val, IsLifetimeExtended), Base(Base), T(T) {} |
| 644 | |
| 645 | bool isLifetimeExtended() const { return Value.getInt(); } |
| 646 | bool endLifetime(EvalInfo &Info, bool RunDestructors) { |
| 647 | if (RunDestructors) { |
| 648 | SourceLocation Loc; |
| 649 | if (const ValueDecl *VD = Base.dyn_cast<const ValueDecl*>()) |
| 650 | Loc = VD->getLocation(); |
| 651 | else if (const Expr *E = Base.dyn_cast<const Expr*>()) |
| 652 | Loc = E->getExprLoc(); |
| 653 | return HandleDestruction(Info, Loc, Base, *Value.getPointer(), T); |
| 654 | } |
| 655 | *Value.getPointer() = APValue(); |
| 656 | return true; |
| 657 | } |
| 658 | |
| 659 | bool hasSideEffect() { |
| 660 | return T.isDestructedType(); |
| 661 | } |
| 662 | }; |
| 663 | |
| 664 | /// A reference to an object whose construction we are currently evaluating. |
| 665 | struct ObjectUnderConstruction { |
| 666 | APValue::LValueBase Base; |
| 667 | ArrayRef<APValue::LValuePathEntry> Path; |
| 668 | friend bool operator==(const ObjectUnderConstruction &LHS, |
| 669 | const ObjectUnderConstruction &RHS) { |
| 670 | return LHS.Base == RHS.Base && LHS.Path == RHS.Path; |
| 671 | } |
| 672 | friend llvm::hash_code hash_value(const ObjectUnderConstruction &Obj) { |
| 673 | return llvm::hash_combine(Obj.Base, Obj.Path); |
| 674 | } |
| 675 | }; |
| 676 | enum class ConstructionPhase { |
| 677 | None, |
| 678 | Bases, |
| 679 | AfterBases, |
| 680 | AfterFields, |
| 681 | Destroying, |
| 682 | DestroyingBases |
| 683 | }; |
| 684 | } |
| 685 | |
| 686 | namespace llvm { |
| 687 | template<> struct DenseMapInfo<ObjectUnderConstruction> { |
| 688 | using Base = DenseMapInfo<APValue::LValueBase>; |
| 689 | static ObjectUnderConstruction getEmptyKey() { |
| 690 | return {Base::getEmptyKey(), {}}; } |
| 691 | static ObjectUnderConstruction getTombstoneKey() { |
| 692 | return {Base::getTombstoneKey(), {}}; |
| 693 | } |
| 694 | static unsigned getHashValue(const ObjectUnderConstruction &Object) { |
| 695 | return hash_value(Object); |
| 696 | } |
| 697 | static bool isEqual(const ObjectUnderConstruction &LHS, |
| 698 | const ObjectUnderConstruction &RHS) { |
| 699 | return LHS == RHS; |
| 700 | } |
| 701 | }; |
| 702 | } |
| 703 | |
| 704 | namespace { |
| 705 | /// A dynamically-allocated heap object. |
| 706 | struct DynAlloc { |
| 707 | /// The value of this heap-allocated object. |
| 708 | APValue Value; |
| 709 | /// The allocating expression; used for diagnostics. Either a CXXNewExpr |
| 710 | /// or a CallExpr (the latter is for direct calls to operator new inside |
| 711 | /// std::allocator<T>::allocate). |
| 712 | const Expr *AllocExpr = nullptr; |
| 713 | |
| 714 | enum Kind { |
| 715 | New, |
| 716 | ArrayNew, |
| 717 | StdAllocator |
| 718 | }; |
| 719 | |
| 720 | /// Get the kind of the allocation. This must match between allocation |
| 721 | /// and deallocation. |
| 722 | Kind getKind() const { |
| 723 | if (auto *NE = dyn_cast<CXXNewExpr>(AllocExpr)) |
| 724 | return NE->isArray() ? ArrayNew : New; |
| 725 | assert(isa<CallExpr>(AllocExpr))((isa<CallExpr>(AllocExpr)) ? static_cast<void> ( 0) : __assert_fail ("isa<CallExpr>(AllocExpr)", "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 725, __PRETTY_FUNCTION__)); |
| 726 | return StdAllocator; |
| 727 | } |
| 728 | }; |
| 729 | |
| 730 | struct DynAllocOrder { |
| 731 | bool operator()(DynamicAllocLValue L, DynamicAllocLValue R) const { |
| 732 | return L.getIndex() < R.getIndex(); |
| 733 | } |
| 734 | }; |
| 735 | |
| 736 | /// EvalInfo - This is a private struct used by the evaluator to capture |
| 737 | /// information about a subexpression as it is folded. It retains information |
| 738 | /// about the AST context, but also maintains information about the folded |
| 739 | /// expression. |
| 740 | /// |
| 741 | /// If an expression could be evaluated, it is still possible it is not a C |
| 742 | /// "integer constant expression" or constant expression. If not, this struct |
| 743 | /// captures information about how and why not. |
| 744 | /// |
| 745 | /// One bit of information passed *into* the request for constant folding |
| 746 | /// indicates whether the subexpression is "evaluated" or not according to C |
| 747 | /// rules. For example, the RHS of (0 && foo()) is not evaluated. We can |
| 748 | /// evaluate the expression regardless of what the RHS is, but C only allows |
| 749 | /// certain things in certain situations. |
| 750 | class EvalInfo : public interp::State { |
| 751 | public: |
| 752 | ASTContext &Ctx; |
| 753 | |
| 754 | /// EvalStatus - Contains information about the evaluation. |
| 755 | Expr::EvalStatus &EvalStatus; |
| 756 | |
| 757 | /// CurrentCall - The top of the constexpr call stack. |
| 758 | CallStackFrame *CurrentCall; |
| 759 | |
| 760 | /// CallStackDepth - The number of calls in the call stack right now. |
| 761 | unsigned CallStackDepth; |
| 762 | |
| 763 | /// NextCallIndex - The next call index to assign. |
| 764 | unsigned NextCallIndex; |
| 765 | |
| 766 | /// StepsLeft - The remaining number of evaluation steps we're permitted |
| 767 | /// to perform. This is essentially a limit for the number of statements |
| 768 | /// we will evaluate. |
| 769 | unsigned StepsLeft; |
| 770 | |
| 771 | /// Enable the experimental new constant interpreter. If an expression is |
| 772 | /// not supported by the interpreter, an error is triggered. |
| 773 | bool EnableNewConstInterp; |
| 774 | |
| 775 | /// BottomFrame - The frame in which evaluation started. This must be |
| 776 | /// initialized after CurrentCall and CallStackDepth. |
| 777 | CallStackFrame BottomFrame; |
| 778 | |
| 779 | /// A stack of values whose lifetimes end at the end of some surrounding |
| 780 | /// evaluation frame. |
| 781 | llvm::SmallVector<Cleanup, 16> CleanupStack; |
| 782 | |
| 783 | /// EvaluatingDecl - This is the declaration whose initializer is being |
| 784 | /// evaluated, if any. |
| 785 | APValue::LValueBase EvaluatingDecl; |
| 786 | |
| 787 | enum class EvaluatingDeclKind { |
| 788 | None, |
| 789 | /// We're evaluating the construction of EvaluatingDecl. |
| 790 | Ctor, |
| 791 | /// We're evaluating the destruction of EvaluatingDecl. |
| 792 | Dtor, |
| 793 | }; |
| 794 | EvaluatingDeclKind IsEvaluatingDecl = EvaluatingDeclKind::None; |
| 795 | |
| 796 | /// EvaluatingDeclValue - This is the value being constructed for the |
| 797 | /// declaration whose initializer is being evaluated, if any. |
| 798 | APValue *EvaluatingDeclValue; |
| 799 | |
| 800 | /// Set of objects that are currently being constructed. |
| 801 | llvm::DenseMap<ObjectUnderConstruction, ConstructionPhase> |
| 802 | ObjectsUnderConstruction; |
| 803 | |
| 804 | /// Current heap allocations, along with the location where each was |
| 805 | /// allocated. We use std::map here because we need stable addresses |
| 806 | /// for the stored APValues. |
| 807 | std::map<DynamicAllocLValue, DynAlloc, DynAllocOrder> HeapAllocs; |
| 808 | |
| 809 | /// The number of heap allocations performed so far in this evaluation. |
| 810 | unsigned NumHeapAllocs = 0; |
| 811 | |
| 812 | struct EvaluatingConstructorRAII { |
| 813 | EvalInfo &EI; |
| 814 | ObjectUnderConstruction Object; |
| 815 | bool DidInsert; |
| 816 | EvaluatingConstructorRAII(EvalInfo &EI, ObjectUnderConstruction Object, |
| 817 | bool HasBases) |
| 818 | : EI(EI), Object(Object) { |
| 819 | DidInsert = |
| 820 | EI.ObjectsUnderConstruction |
| 821 | .insert({Object, HasBases ? ConstructionPhase::Bases |
| 822 | : ConstructionPhase::AfterBases}) |
| 823 | .second; |
| 824 | } |
| 825 | void finishedConstructingBases() { |
| 826 | EI.ObjectsUnderConstruction[Object] = ConstructionPhase::AfterBases; |
| 827 | } |
| 828 | void finishedConstructingFields() { |
| 829 | EI.ObjectsUnderConstruction[Object] = ConstructionPhase::AfterFields; |
| 830 | } |
| 831 | ~EvaluatingConstructorRAII() { |
| 832 | if (DidInsert) EI.ObjectsUnderConstruction.erase(Object); |
| 833 | } |
| 834 | }; |
| 835 | |
| 836 | struct EvaluatingDestructorRAII { |
| 837 | EvalInfo &EI; |
| 838 | ObjectUnderConstruction Object; |
| 839 | bool DidInsert; |
| 840 | EvaluatingDestructorRAII(EvalInfo &EI, ObjectUnderConstruction Object) |
| 841 | : EI(EI), Object(Object) { |
| 842 | DidInsert = EI.ObjectsUnderConstruction |
| 843 | .insert({Object, ConstructionPhase::Destroying}) |
| 844 | .second; |
| 845 | } |
| 846 | void startedDestroyingBases() { |
| 847 | EI.ObjectsUnderConstruction[Object] = |
| 848 | ConstructionPhase::DestroyingBases; |
| 849 | } |
| 850 | ~EvaluatingDestructorRAII() { |
| 851 | if (DidInsert) |
| 852 | EI.ObjectsUnderConstruction.erase(Object); |
| 853 | } |
| 854 | }; |
| 855 | |
| 856 | ConstructionPhase |
| 857 | isEvaluatingCtorDtor(APValue::LValueBase Base, |
| 858 | ArrayRef<APValue::LValuePathEntry> Path) { |
| 859 | return ObjectsUnderConstruction.lookup({Base, Path}); |
| 860 | } |
| 861 | |
| 862 | /// If we're currently speculatively evaluating, the outermost call stack |
| 863 | /// depth at which we can mutate state, otherwise 0. |
| 864 | unsigned SpeculativeEvaluationDepth = 0; |
| 865 | |
| 866 | /// The current array initialization index, if we're performing array |
| 867 | /// initialization. |
| 868 | uint64_t ArrayInitIndex = -1; |
| 869 | |
| 870 | /// HasActiveDiagnostic - Was the previous diagnostic stored? If so, further |
| 871 | /// notes attached to it will also be stored, otherwise they will not be. |
| 872 | bool HasActiveDiagnostic; |
| 873 | |
| 874 | /// Have we emitted a diagnostic explaining why we couldn't constant |
| 875 | /// fold (not just why it's not strictly a constant expression)? |
| 876 | bool HasFoldFailureDiagnostic; |
| 877 | |
| 878 | /// Whether or not we're in a context where the front end requires a |
| 879 | /// constant value. |
| 880 | bool InConstantContext; |
| 881 | |
| 882 | /// Whether we're checking that an expression is a potential constant |
| 883 | /// expression. If so, do not fail on constructs that could become constant |
| 884 | /// later on (such as a use of an undefined global). |
| 885 | bool CheckingPotentialConstantExpression = false; |
| 886 | |
| 887 | /// Whether we're checking for an expression that has undefined behavior. |
| 888 | /// If so, we will produce warnings if we encounter an operation that is |
| 889 | /// always undefined. |
| 890 | bool CheckingForUndefinedBehavior = false; |
| 891 | |
| 892 | enum EvaluationMode { |
| 893 | /// Evaluate as a constant expression. Stop if we find that the expression |
| 894 | /// is not a constant expression. |
| 895 | EM_ConstantExpression, |
| 896 | |
| 897 | /// Evaluate as a constant expression. Stop if we find that the expression |
| 898 | /// is not a constant expression. Some expressions can be retried in the |
| 899 | /// optimizer if we don't constant fold them here, but in an unevaluated |
| 900 | /// context we try to fold them immediately since the optimizer never |
| 901 | /// gets a chance to look at it. |
| 902 | EM_ConstantExpressionUnevaluated, |
| 903 | |
| 904 | /// Fold the expression to a constant. Stop if we hit a side-effect that |
| 905 | /// we can't model. |
| 906 | EM_ConstantFold, |
| 907 | |
| 908 | /// Evaluate in any way we know how. Don't worry about side-effects that |
| 909 | /// can't be modeled. |
| 910 | EM_IgnoreSideEffects, |
| 911 | } EvalMode; |
| 912 | |
| 913 | /// Are we checking whether the expression is a potential constant |
| 914 | /// expression? |
| 915 | bool checkingPotentialConstantExpression() const override { |
| 916 | return CheckingPotentialConstantExpression; |
| 917 | } |
| 918 | |
| 919 | /// Are we checking an expression for overflow? |
| 920 | // FIXME: We should check for any kind of undefined or suspicious behavior |
| 921 | // in such constructs, not just overflow. |
| 922 | bool checkingForUndefinedBehavior() const override { |
| 923 | return CheckingForUndefinedBehavior; |
| 924 | } |
| 925 | |
| 926 | EvalInfo(const ASTContext &C, Expr::EvalStatus &S, EvaluationMode Mode) |
| 927 | : Ctx(const_cast<ASTContext &>(C)), EvalStatus(S), CurrentCall(nullptr), |
| 928 | CallStackDepth(0), NextCallIndex(1), |
| 929 | StepsLeft(C.getLangOpts().ConstexprStepLimit), |
| 930 | EnableNewConstInterp(C.getLangOpts().EnableNewConstInterp), |
| 931 | BottomFrame(*this, SourceLocation(), nullptr, nullptr, nullptr), |
| 932 | EvaluatingDecl((const ValueDecl *)nullptr), |
| 933 | EvaluatingDeclValue(nullptr), HasActiveDiagnostic(false), |
| 934 | HasFoldFailureDiagnostic(false), InConstantContext(false), |
| 935 | EvalMode(Mode) {} |
| 936 | |
| 937 | ~EvalInfo() { |
| 938 | discardCleanups(); |
| 939 | } |
| 940 | |
| 941 | void setEvaluatingDecl(APValue::LValueBase Base, APValue &Value, |
| 942 | EvaluatingDeclKind EDK = EvaluatingDeclKind::Ctor) { |
| 943 | EvaluatingDecl = Base; |
| 944 | IsEvaluatingDecl = EDK; |
| 945 | EvaluatingDeclValue = &Value; |
| 946 | } |
| 947 | |
| 948 | bool CheckCallLimit(SourceLocation Loc) { |
| 949 | // Don't perform any constexpr calls (other than the call we're checking) |
| 950 | // when checking a potential constant expression. |
| 951 | if (checkingPotentialConstantExpression() && CallStackDepth > 1) |
| 952 | return false; |
| 953 | if (NextCallIndex == 0) { |
| 954 | // NextCallIndex has wrapped around. |
| 955 | FFDiag(Loc, diag::note_constexpr_call_limit_exceeded); |
| 956 | return false; |
| 957 | } |
| 958 | if (CallStackDepth <= getLangOpts().ConstexprCallDepth) |
| 959 | return true; |
| 960 | FFDiag(Loc, diag::note_constexpr_depth_limit_exceeded) |
| 961 | << getLangOpts().ConstexprCallDepth; |
| 962 | return false; |
| 963 | } |
| 964 | |
| 965 | std::pair<CallStackFrame *, unsigned> |
| 966 | getCallFrameAndDepth(unsigned CallIndex) { |
| 967 | assert(CallIndex && "no call index in getCallFrameAndDepth")((CallIndex && "no call index in getCallFrameAndDepth" ) ? static_cast<void> (0) : __assert_fail ("CallIndex && \"no call index in getCallFrameAndDepth\"" , "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 967, __PRETTY_FUNCTION__)); |
| 968 | // We will eventually hit BottomFrame, which has Index 1, so Frame can't |
| 969 | // be null in this loop. |
| 970 | unsigned Depth = CallStackDepth; |
| 971 | CallStackFrame *Frame = CurrentCall; |
| 972 | while (Frame->Index > CallIndex) { |
| 973 | Frame = Frame->Caller; |
| 974 | --Depth; |
| 975 | } |
| 976 | if (Frame->Index == CallIndex) |
| 977 | return {Frame, Depth}; |
| 978 | return {nullptr, 0}; |
| 979 | } |
| 980 | |
| 981 | bool nextStep(const Stmt *S) { |
| 982 | if (!StepsLeft) { |
| 983 | FFDiag(S->getBeginLoc(), diag::note_constexpr_step_limit_exceeded); |
| 984 | return false; |
| 985 | } |
| 986 | --StepsLeft; |
| 987 | return true; |
| 988 | } |
| 989 | |
| 990 | APValue *createHeapAlloc(const Expr *E, QualType T, LValue &LV); |
| 991 | |
| 992 | Optional<DynAlloc*> lookupDynamicAlloc(DynamicAllocLValue DA) { |
| 993 | Optional<DynAlloc*> Result; |
| 994 | auto It = HeapAllocs.find(DA); |
| 995 | if (It != HeapAllocs.end()) |
| 996 | Result = &It->second; |
| 997 | return Result; |
| 998 | } |
| 999 | |
| 1000 | /// Information about a stack frame for std::allocator<T>::[de]allocate. |
| 1001 | struct StdAllocatorCaller { |
| 1002 | unsigned FrameIndex; |
| 1003 | QualType ElemType; |
| 1004 | explicit operator bool() const { return FrameIndex != 0; }; |
| 1005 | }; |
| 1006 | |
| 1007 | StdAllocatorCaller getStdAllocatorCaller(StringRef FnName) const { |
| 1008 | for (const CallStackFrame *Call = CurrentCall; Call != &BottomFrame; |
| 1009 | Call = Call->Caller) { |
| 1010 | const auto *MD = dyn_cast_or_null<CXXMethodDecl>(Call->Callee); |
| 1011 | if (!MD) |
| 1012 | continue; |
| 1013 | const IdentifierInfo *FnII = MD->getIdentifier(); |
| 1014 | if (!FnII || !FnII->isStr(FnName)) |
| 1015 | continue; |
| 1016 | |
| 1017 | const auto *CTSD = |
| 1018 | dyn_cast<ClassTemplateSpecializationDecl>(MD->getParent()); |
| 1019 | if (!CTSD) |
| 1020 | continue; |
| 1021 | |
| 1022 | const IdentifierInfo *ClassII = CTSD->getIdentifier(); |
| 1023 | const TemplateArgumentList &TAL = CTSD->getTemplateArgs(); |
| 1024 | if (CTSD->isInStdNamespace() && ClassII && |
| 1025 | ClassII->isStr("allocator") && TAL.size() >= 1 && |
| 1026 | TAL[0].getKind() == TemplateArgument::Type) |
| 1027 | return {Call->Index, TAL[0].getAsType()}; |
| 1028 | } |
| 1029 | |
| 1030 | return {}; |
| 1031 | } |
| 1032 | |
| 1033 | void performLifetimeExtension() { |
| 1034 | // Disable the cleanups for lifetime-extended temporaries. |
| 1035 | CleanupStack.erase( |
| 1036 | std::remove_if(CleanupStack.begin(), CleanupStack.end(), |
| 1037 | [](Cleanup &C) { return C.isLifetimeExtended(); }), |
| 1038 | CleanupStack.end()); |
| 1039 | } |
| 1040 | |
| 1041 | /// Throw away any remaining cleanups at the end of evaluation. If any |
| 1042 | /// cleanups would have had a side-effect, note that as an unmodeled |
| 1043 | /// side-effect and return false. Otherwise, return true. |
| 1044 | bool discardCleanups() { |
| 1045 | for (Cleanup &C : CleanupStack) { |
| 1046 | if (C.hasSideEffect() && !noteSideEffect()) { |
| 1047 | CleanupStack.clear(); |
| 1048 | return false; |
| 1049 | } |
| 1050 | } |
| 1051 | CleanupStack.clear(); |
| 1052 | return true; |
| 1053 | } |
| 1054 | |
| 1055 | private: |
| 1056 | interp::Frame *getCurrentFrame() override { return CurrentCall; } |
| 1057 | const interp::Frame *getBottomFrame() const override { return &BottomFrame; } |
| 1058 | |
| 1059 | bool hasActiveDiagnostic() override { return HasActiveDiagnostic; } |
| 1060 | void setActiveDiagnostic(bool Flag) override { HasActiveDiagnostic = Flag; } |
| 1061 | |
| 1062 | void setFoldFailureDiagnostic(bool Flag) override { |
| 1063 | HasFoldFailureDiagnostic = Flag; |
| 1064 | } |
| 1065 | |
| 1066 | Expr::EvalStatus &getEvalStatus() const override { return EvalStatus; } |
| 1067 | |
| 1068 | ASTContext &getCtx() const override { return Ctx; } |
| 1069 | |
| 1070 | // If we have a prior diagnostic, it will be noting that the expression |
| 1071 | // isn't a constant expression. This diagnostic is more important, |
| 1072 | // unless we require this evaluation to produce a constant expression. |
| 1073 | // |
| 1074 | // FIXME: We might want to show both diagnostics to the user in |
| 1075 | // EM_ConstantFold mode. |
| 1076 | bool hasPriorDiagnostic() override { |
| 1077 | if (!EvalStatus.Diag->empty()) { |
| 1078 | switch (EvalMode) { |
| 1079 | case EM_ConstantFold: |
| 1080 | case EM_IgnoreSideEffects: |
| 1081 | if (!HasFoldFailureDiagnostic) |
| 1082 | break; |
| 1083 | // We've already failed to fold something. Keep that diagnostic. |
| 1084 | LLVM_FALLTHROUGH[[gnu::fallthrough]]; |
| 1085 | case EM_ConstantExpression: |
| 1086 | case EM_ConstantExpressionUnevaluated: |
| 1087 | setActiveDiagnostic(false); |
| 1088 | return true; |
| 1089 | } |
| 1090 | } |
| 1091 | return false; |
| 1092 | } |
| 1093 | |
| 1094 | unsigned getCallStackDepth() override { return CallStackDepth; } |
| 1095 | |
| 1096 | public: |
| 1097 | /// Should we continue evaluation after encountering a side-effect that we |
| 1098 | /// couldn't model? |
| 1099 | bool keepEvaluatingAfterSideEffect() { |
| 1100 | switch (EvalMode) { |
| 1101 | case EM_IgnoreSideEffects: |
| 1102 | return true; |
| 1103 | |
| 1104 | case EM_ConstantExpression: |
| 1105 | case EM_ConstantExpressionUnevaluated: |
| 1106 | case EM_ConstantFold: |
| 1107 | // By default, assume any side effect might be valid in some other |
| 1108 | // evaluation of this expression from a different context. |
| 1109 | return checkingPotentialConstantExpression() || |
| 1110 | checkingForUndefinedBehavior(); |
| 1111 | } |
| 1112 | llvm_unreachable("Missed EvalMode case")::llvm::llvm_unreachable_internal("Missed EvalMode case", "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 1112); |
| 1113 | } |
| 1114 | |
| 1115 | /// Note that we have had a side-effect, and determine whether we should |
| 1116 | /// keep evaluating. |
| 1117 | bool noteSideEffect() { |
| 1118 | EvalStatus.HasSideEffects = true; |
| 1119 | return keepEvaluatingAfterSideEffect(); |
| 1120 | } |
| 1121 | |
| 1122 | /// Should we continue evaluation after encountering undefined behavior? |
| 1123 | bool keepEvaluatingAfterUndefinedBehavior() { |
| 1124 | switch (EvalMode) { |
| 1125 | case EM_IgnoreSideEffects: |
| 1126 | case EM_ConstantFold: |
| 1127 | return true; |
| 1128 | |
| 1129 | case EM_ConstantExpression: |
| 1130 | case EM_ConstantExpressionUnevaluated: |
| 1131 | return checkingForUndefinedBehavior(); |
| 1132 | } |
| 1133 | llvm_unreachable("Missed EvalMode case")::llvm::llvm_unreachable_internal("Missed EvalMode case", "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 1133); |
| 1134 | } |
| 1135 | |
| 1136 | /// Note that we hit something that was technically undefined behavior, but |
| 1137 | /// that we can evaluate past it (such as signed overflow or floating-point |
| 1138 | /// division by zero.) |
| 1139 | bool noteUndefinedBehavior() override { |
| 1140 | EvalStatus.HasUndefinedBehavior = true; |
| 1141 | return keepEvaluatingAfterUndefinedBehavior(); |
| 1142 | } |
| 1143 | |
| 1144 | /// Should we continue evaluation as much as possible after encountering a |
| 1145 | /// construct which can't be reduced to a value? |
| 1146 | bool keepEvaluatingAfterFailure() const override { |
| 1147 | if (!StepsLeft) |
| 1148 | return false; |
| 1149 | |
| 1150 | switch (EvalMode) { |
| 1151 | case EM_ConstantExpression: |
| 1152 | case EM_ConstantExpressionUnevaluated: |
| 1153 | case EM_ConstantFold: |
| 1154 | case EM_IgnoreSideEffects: |
| 1155 | return checkingPotentialConstantExpression() || |
| 1156 | checkingForUndefinedBehavior(); |
| 1157 | } |
| 1158 | llvm_unreachable("Missed EvalMode case")::llvm::llvm_unreachable_internal("Missed EvalMode case", "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 1158); |
| 1159 | } |
| 1160 | |
| 1161 | /// Notes that we failed to evaluate an expression that other expressions |
| 1162 | /// directly depend on, and determine if we should keep evaluating. This |
| 1163 | /// should only be called if we actually intend to keep evaluating. |
| 1164 | /// |
| 1165 | /// Call noteSideEffect() instead if we may be able to ignore the value that |
| 1166 | /// we failed to evaluate, e.g. if we failed to evaluate Foo() in: |
| 1167 | /// |
| 1168 | /// (Foo(), 1) // use noteSideEffect |
| 1169 | /// (Foo() || true) // use noteSideEffect |
| 1170 | /// Foo() + 1 // use noteFailure |
| 1171 | LLVM_NODISCARD[[clang::warn_unused_result]] bool noteFailure() { |
| 1172 | // Failure when evaluating some expression often means there is some |
| 1173 | // subexpression whose evaluation was skipped. Therefore, (because we |
| 1174 | // don't track whether we skipped an expression when unwinding after an |
| 1175 | // evaluation failure) every evaluation failure that bubbles up from a |
| 1176 | // subexpression implies that a side-effect has potentially happened. We |
| 1177 | // skip setting the HasSideEffects flag to true until we decide to |
| 1178 | // continue evaluating after that point, which happens here. |
| 1179 | bool KeepGoing = keepEvaluatingAfterFailure(); |
| 1180 | EvalStatus.HasSideEffects |= KeepGoing; |
| 1181 | return KeepGoing; |
| 1182 | } |
| 1183 | |
| 1184 | class ArrayInitLoopIndex { |
| 1185 | EvalInfo &Info; |
| 1186 | uint64_t OuterIndex; |
| 1187 | |
| 1188 | public: |
| 1189 | ArrayInitLoopIndex(EvalInfo &Info) |
| 1190 | : Info(Info), OuterIndex(Info.ArrayInitIndex) { |
| 1191 | Info.ArrayInitIndex = 0; |
| 1192 | } |
| 1193 | ~ArrayInitLoopIndex() { Info.ArrayInitIndex = OuterIndex; } |
| 1194 | |
| 1195 | operator uint64_t&() { return Info.ArrayInitIndex; } |
| 1196 | }; |
| 1197 | }; |
| 1198 | |
| 1199 | /// Object used to treat all foldable expressions as constant expressions. |
| 1200 | struct FoldConstant { |
| 1201 | EvalInfo &Info; |
| 1202 | bool Enabled; |
| 1203 | bool HadNoPriorDiags; |
| 1204 | EvalInfo::EvaluationMode OldMode; |
| 1205 | |
| 1206 | explicit FoldConstant(EvalInfo &Info, bool Enabled) |
| 1207 | : Info(Info), |
| 1208 | Enabled(Enabled), |
| 1209 | HadNoPriorDiags(Info.EvalStatus.Diag && |
| 1210 | Info.EvalStatus.Diag->empty() && |
| 1211 | !Info.EvalStatus.HasSideEffects), |
| 1212 | OldMode(Info.EvalMode) { |
| 1213 | if (Enabled) |
| 1214 | Info.EvalMode = EvalInfo::EM_ConstantFold; |
| 1215 | } |
| 1216 | void keepDiagnostics() { Enabled = false; } |
| 1217 | ~FoldConstant() { |
| 1218 | if (Enabled && HadNoPriorDiags && !Info.EvalStatus.Diag->empty() && |
| 1219 | !Info.EvalStatus.HasSideEffects) |
| 1220 | Info.EvalStatus.Diag->clear(); |
| 1221 | Info.EvalMode = OldMode; |
| 1222 | } |
| 1223 | }; |
| 1224 | |
| 1225 | /// RAII object used to set the current evaluation mode to ignore |
| 1226 | /// side-effects. |
| 1227 | struct IgnoreSideEffectsRAII { |
| 1228 | EvalInfo &Info; |
| 1229 | EvalInfo::EvaluationMode OldMode; |
| 1230 | explicit IgnoreSideEffectsRAII(EvalInfo &Info) |
| 1231 | : Info(Info), OldMode(Info.EvalMode) { |
| 1232 | Info.EvalMode = EvalInfo::EM_IgnoreSideEffects; |
| 1233 | } |
| 1234 | |
| 1235 | ~IgnoreSideEffectsRAII() { Info.EvalMode = OldMode; } |
| 1236 | }; |
| 1237 | |
| 1238 | /// RAII object used to optionally suppress diagnostics and side-effects from |
| 1239 | /// a speculative evaluation. |
| 1240 | class SpeculativeEvaluationRAII { |
| 1241 | EvalInfo *Info = nullptr; |
| 1242 | Expr::EvalStatus OldStatus; |
| 1243 | unsigned OldSpeculativeEvaluationDepth; |
| 1244 | |
| 1245 | void moveFromAndCancel(SpeculativeEvaluationRAII &&Other) { |
| 1246 | Info = Other.Info; |
| 1247 | OldStatus = Other.OldStatus; |
| 1248 | OldSpeculativeEvaluationDepth = Other.OldSpeculativeEvaluationDepth; |
| 1249 | Other.Info = nullptr; |
| 1250 | } |
| 1251 | |
| 1252 | void maybeRestoreState() { |
| 1253 | if (!Info) |
| 1254 | return; |
| 1255 | |
| 1256 | Info->EvalStatus = OldStatus; |
| 1257 | Info->SpeculativeEvaluationDepth = OldSpeculativeEvaluationDepth; |
| 1258 | } |
| 1259 | |
| 1260 | public: |
| 1261 | SpeculativeEvaluationRAII() = default; |
| 1262 | |
| 1263 | SpeculativeEvaluationRAII( |
| 1264 | EvalInfo &Info, SmallVectorImpl<PartialDiagnosticAt> *NewDiag = nullptr) |
| 1265 | : Info(&Info), OldStatus(Info.EvalStatus), |
| 1266 | OldSpeculativeEvaluationDepth(Info.SpeculativeEvaluationDepth) { |
| 1267 | Info.EvalStatus.Diag = NewDiag; |
| 1268 | Info.SpeculativeEvaluationDepth = Info.CallStackDepth + 1; |
| 1269 | } |
| 1270 | |
| 1271 | SpeculativeEvaluationRAII(const SpeculativeEvaluationRAII &Other) = delete; |
| 1272 | SpeculativeEvaluationRAII(SpeculativeEvaluationRAII &&Other) { |
| 1273 | moveFromAndCancel(std::move(Other)); |
| 1274 | } |
| 1275 | |
| 1276 | SpeculativeEvaluationRAII &operator=(SpeculativeEvaluationRAII &&Other) { |
| 1277 | maybeRestoreState(); |
| 1278 | moveFromAndCancel(std::move(Other)); |
| 1279 | return *this; |
| 1280 | } |
| 1281 | |
| 1282 | ~SpeculativeEvaluationRAII() { maybeRestoreState(); } |
| 1283 | }; |
| 1284 | |
| 1285 | /// RAII object wrapping a full-expression or block scope, and handling |
| 1286 | /// the ending of the lifetime of temporaries created within it. |
| 1287 | template<bool IsFullExpression> |
| 1288 | class ScopeRAII { |
| 1289 | EvalInfo &Info; |
| 1290 | unsigned OldStackSize; |
| 1291 | public: |
| 1292 | ScopeRAII(EvalInfo &Info) |
| 1293 | : Info(Info), OldStackSize(Info.CleanupStack.size()) { |
| 1294 | // Push a new temporary version. This is needed to distinguish between |
| 1295 | // temporaries created in different iterations of a loop. |
| 1296 | Info.CurrentCall->pushTempVersion(); |
| 1297 | } |
| 1298 | bool destroy(bool RunDestructors = true) { |
| 1299 | bool OK = cleanup(Info, RunDestructors, OldStackSize); |
| 1300 | OldStackSize = -1U; |
| 1301 | return OK; |
| 1302 | } |
| 1303 | ~ScopeRAII() { |
| 1304 | if (OldStackSize != -1U) |
| 1305 | destroy(false); |
| 1306 | // Body moved to a static method to encourage the compiler to inline away |
| 1307 | // instances of this class. |
| 1308 | Info.CurrentCall->popTempVersion(); |
| 1309 | } |
| 1310 | private: |
| 1311 | static bool cleanup(EvalInfo &Info, bool RunDestructors, |
| 1312 | unsigned OldStackSize) { |
| 1313 | assert(OldStackSize <= Info.CleanupStack.size() &&((OldStackSize <= Info.CleanupStack.size() && "running cleanups out of order?" ) ? static_cast<void> (0) : __assert_fail ("OldStackSize <= Info.CleanupStack.size() && \"running cleanups out of order?\"" , "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 1314, __PRETTY_FUNCTION__)) |
| 1314 | "running cleanups out of order?")((OldStackSize <= Info.CleanupStack.size() && "running cleanups out of order?" ) ? static_cast<void> (0) : __assert_fail ("OldStackSize <= Info.CleanupStack.size() && \"running cleanups out of order?\"" , "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 1314, __PRETTY_FUNCTION__)); |
| 1315 | |
| 1316 | // Run all cleanups for a block scope, and non-lifetime-extended cleanups |
| 1317 | // for a full-expression scope. |
| 1318 | bool Success = true; |
| 1319 | for (unsigned I = Info.CleanupStack.size(); I > OldStackSize; --I) { |
| 1320 | if (!(IsFullExpression && |
| 1321 | Info.CleanupStack[I - 1].isLifetimeExtended())) { |
| 1322 | if (!Info.CleanupStack[I - 1].endLifetime(Info, RunDestructors)) { |
| 1323 | Success = false; |
| 1324 | break; |
| 1325 | } |
| 1326 | } |
| 1327 | } |
| 1328 | |
| 1329 | // Compact lifetime-extended cleanups. |
| 1330 | auto NewEnd = Info.CleanupStack.begin() + OldStackSize; |
| 1331 | if (IsFullExpression) |
| 1332 | NewEnd = |
| 1333 | std::remove_if(NewEnd, Info.CleanupStack.end(), |
| 1334 | [](Cleanup &C) { return !C.isLifetimeExtended(); }); |
| 1335 | Info.CleanupStack.erase(NewEnd, Info.CleanupStack.end()); |
| 1336 | return Success; |
| 1337 | } |
| 1338 | }; |
| 1339 | typedef ScopeRAII<false> BlockScopeRAII; |
| 1340 | typedef ScopeRAII<true> FullExpressionRAII; |
| 1341 | } |
| 1342 | |
| 1343 | bool SubobjectDesignator::checkSubobject(EvalInfo &Info, const Expr *E, |
| 1344 | CheckSubobjectKind CSK) { |
| 1345 | if (Invalid) |
| 1346 | return false; |
| 1347 | if (isOnePastTheEnd()) { |
| 1348 | Info.CCEDiag(E, diag::note_constexpr_past_end_subobject) |
| 1349 | << CSK; |
| 1350 | setInvalid(); |
| 1351 | return false; |
| 1352 | } |
| 1353 | // Note, we do not diagnose if isMostDerivedAnUnsizedArray(), because there |
| 1354 | // must actually be at least one array element; even a VLA cannot have a |
| 1355 | // bound of zero. And if our index is nonzero, we already had a CCEDiag. |
| 1356 | return true; |
| 1357 | } |
| 1358 | |
| 1359 | void SubobjectDesignator::diagnoseUnsizedArrayPointerArithmetic(EvalInfo &Info, |
| 1360 | const Expr *E) { |
| 1361 | Info.CCEDiag(E, diag::note_constexpr_unsized_array_indexed); |
| 1362 | // Do not set the designator as invalid: we can represent this situation, |
| 1363 | // and correct handling of __builtin_object_size requires us to do so. |
| 1364 | } |
| 1365 | |
| 1366 | void SubobjectDesignator::diagnosePointerArithmetic(EvalInfo &Info, |
| 1367 | const Expr *E, |
| 1368 | const APSInt &N) { |
| 1369 | // If we're complaining, we must be able to statically determine the size of |
| 1370 | // the most derived array. |
| 1371 | if (MostDerivedPathLength == Entries.size() && MostDerivedIsArrayElement) |
| 1372 | Info.CCEDiag(E, diag::note_constexpr_array_index) |
| 1373 | << N << /*array*/ 0 |
| 1374 | << static_cast<unsigned>(getMostDerivedArraySize()); |
| 1375 | else |
| 1376 | Info.CCEDiag(E, diag::note_constexpr_array_index) |
| 1377 | << N << /*non-array*/ 1; |
| 1378 | setInvalid(); |
| 1379 | } |
| 1380 | |
| 1381 | CallStackFrame::CallStackFrame(EvalInfo &Info, SourceLocation CallLoc, |
| 1382 | const FunctionDecl *Callee, const LValue *This, |
| 1383 | APValue *Arguments) |
| 1384 | : Info(Info), Caller(Info.CurrentCall), Callee(Callee), This(This), |
| 1385 | Arguments(Arguments), CallLoc(CallLoc), Index(Info.NextCallIndex++) { |
| 1386 | Info.CurrentCall = this; |
| 1387 | ++Info.CallStackDepth; |
| 1388 | } |
| 1389 | |
| 1390 | CallStackFrame::~CallStackFrame() { |
| 1391 | assert(Info.CurrentCall == this && "calls retired out of order")((Info.CurrentCall == this && "calls retired out of order" ) ? static_cast<void> (0) : __assert_fail ("Info.CurrentCall == this && \"calls retired out of order\"" , "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 1391, __PRETTY_FUNCTION__)); |
| 1392 | --Info.CallStackDepth; |
| 1393 | Info.CurrentCall = Caller; |
| 1394 | } |
| 1395 | |
| 1396 | static bool isRead(AccessKinds AK) { |
| 1397 | return AK == AK_Read || AK == AK_ReadObjectRepresentation; |
| 1398 | } |
| 1399 | |
| 1400 | static bool isModification(AccessKinds AK) { |
| 1401 | switch (AK) { |
| 1402 | case AK_Read: |
| 1403 | case AK_ReadObjectRepresentation: |
| 1404 | case AK_MemberCall: |
| 1405 | case AK_DynamicCast: |
| 1406 | case AK_TypeId: |
| 1407 | return false; |
| 1408 | case AK_Assign: |
| 1409 | case AK_Increment: |
| 1410 | case AK_Decrement: |
| 1411 | case AK_Construct: |
| 1412 | case AK_Destroy: |
| 1413 | return true; |
| 1414 | } |
| 1415 | llvm_unreachable("unknown access kind")::llvm::llvm_unreachable_internal("unknown access kind", "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 1415); |
| 1416 | } |
| 1417 | |
| 1418 | static bool isAnyAccess(AccessKinds AK) { |
| 1419 | return isRead(AK) || isModification(AK); |
| 1420 | } |
| 1421 | |
| 1422 | /// Is this an access per the C++ definition? |
| 1423 | static bool isFormalAccess(AccessKinds AK) { |
| 1424 | return isAnyAccess(AK) && AK != AK_Construct && AK != AK_Destroy; |
| 1425 | } |
| 1426 | |
| 1427 | /// Is this kind of axcess valid on an indeterminate object value? |
| 1428 | static bool isValidIndeterminateAccess(AccessKinds AK) { |
| 1429 | switch (AK) { |
| 1430 | case AK_Read: |
| 1431 | case AK_Increment: |
| 1432 | case AK_Decrement: |
| 1433 | // These need the object's value. |
| 1434 | return false; |
| 1435 | |
| 1436 | case AK_ReadObjectRepresentation: |
| 1437 | case AK_Assign: |
| 1438 | case AK_Construct: |
| 1439 | case AK_Destroy: |
| 1440 | // Construction and destruction don't need the value. |
| 1441 | return true; |
| 1442 | |
| 1443 | case AK_MemberCall: |
| 1444 | case AK_DynamicCast: |
| 1445 | case AK_TypeId: |
| 1446 | // These aren't really meaningful on scalars. |
| 1447 | return true; |
| 1448 | } |
| 1449 | llvm_unreachable("unknown access kind")::llvm::llvm_unreachable_internal("unknown access kind", "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 1449); |
| 1450 | } |
| 1451 | |
| 1452 | namespace { |
| 1453 | struct ComplexValue { |
| 1454 | private: |
| 1455 | bool IsInt; |
| 1456 | |
| 1457 | public: |
| 1458 | APSInt IntReal, IntImag; |
| 1459 | APFloat FloatReal, FloatImag; |
| 1460 | |
| 1461 | ComplexValue() : FloatReal(APFloat::Bogus()), FloatImag(APFloat::Bogus()) {} |
| 1462 | |
| 1463 | void makeComplexFloat() { IsInt = false; } |
| 1464 | bool isComplexFloat() const { return !IsInt; } |
| 1465 | APFloat &getComplexFloatReal() { return FloatReal; } |
| 1466 | APFloat &getComplexFloatImag() { return FloatImag; } |
| 1467 | |
| 1468 | void makeComplexInt() { IsInt = true; } |
| 1469 | bool isComplexInt() const { return IsInt; } |
| 1470 | APSInt &getComplexIntReal() { return IntReal; } |
| 1471 | APSInt &getComplexIntImag() { return IntImag; } |
| 1472 | |
| 1473 | void moveInto(APValue &v) const { |
| 1474 | if (isComplexFloat()) |
| 1475 | v = APValue(FloatReal, FloatImag); |
| 1476 | else |
| 1477 | v = APValue(IntReal, IntImag); |
| 1478 | } |
| 1479 | void setFrom(const APValue &v) { |
| 1480 | assert(v.isComplexFloat() || v.isComplexInt())((v.isComplexFloat() || v.isComplexInt()) ? static_cast<void > (0) : __assert_fail ("v.isComplexFloat() || v.isComplexInt()" , "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 1480, __PRETTY_FUNCTION__)); |
| 1481 | if (v.isComplexFloat()) { |
| 1482 | makeComplexFloat(); |
| 1483 | FloatReal = v.getComplexFloatReal(); |
| 1484 | FloatImag = v.getComplexFloatImag(); |
| 1485 | } else { |
| 1486 | makeComplexInt(); |
| 1487 | IntReal = v.getComplexIntReal(); |
| 1488 | IntImag = v.getComplexIntImag(); |
| 1489 | } |
| 1490 | } |
| 1491 | }; |
| 1492 | |
| 1493 | struct LValue { |
| 1494 | APValue::LValueBase Base; |
| 1495 | CharUnits Offset; |
| 1496 | SubobjectDesignator Designator; |
| 1497 | bool IsNullPtr : 1; |
| 1498 | bool InvalidBase : 1; |
| 1499 | |
| 1500 | const APValue::LValueBase getLValueBase() const { return Base; } |
| 1501 | CharUnits &getLValueOffset() { return Offset; } |
| 1502 | const CharUnits &getLValueOffset() const { return Offset; } |
| 1503 | SubobjectDesignator &getLValueDesignator() { return Designator; } |
| 1504 | const SubobjectDesignator &getLValueDesignator() const { return Designator;} |
| 1505 | bool isNullPointer() const { return IsNullPtr;} |
| 1506 | |
| 1507 | unsigned getLValueCallIndex() const { return Base.getCallIndex(); } |
| 1508 | unsigned getLValueVersion() const { return Base.getVersion(); } |
| 1509 | |
| 1510 | void moveInto(APValue &V) const { |
| 1511 | if (Designator.Invalid) |
| 1512 | V = APValue(Base, Offset, APValue::NoLValuePath(), IsNullPtr); |
| 1513 | else { |
| 1514 | assert(!InvalidBase && "APValues can't handle invalid LValue bases")((!InvalidBase && "APValues can't handle invalid LValue bases" ) ? static_cast<void> (0) : __assert_fail ("!InvalidBase && \"APValues can't handle invalid LValue bases\"" , "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 1514, __PRETTY_FUNCTION__)); |
| 1515 | V = APValue(Base, Offset, Designator.Entries, |
| 1516 | Designator.IsOnePastTheEnd, IsNullPtr); |
| 1517 | } |
| 1518 | } |
| 1519 | void setFrom(ASTContext &Ctx, const APValue &V) { |
| 1520 | assert(V.isLValue() && "Setting LValue from a non-LValue?")((V.isLValue() && "Setting LValue from a non-LValue?" ) ? static_cast<void> (0) : __assert_fail ("V.isLValue() && \"Setting LValue from a non-LValue?\"" , "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 1520, __PRETTY_FUNCTION__)); |
| 1521 | Base = V.getLValueBase(); |
| 1522 | Offset = V.getLValueOffset(); |
| 1523 | InvalidBase = false; |
| 1524 | Designator = SubobjectDesignator(Ctx, V); |
| 1525 | IsNullPtr = V.isNullPointer(); |
| 1526 | } |
| 1527 | |
| 1528 | void set(APValue::LValueBase B, bool BInvalid = false) { |
| 1529 | #ifndef NDEBUG |
| 1530 | // We only allow a few types of invalid bases. Enforce that here. |
| 1531 | if (BInvalid) { |
| 1532 | const auto *E = B.get<const Expr *>(); |
| 1533 | assert((isa<MemberExpr>(E) || tryUnwrapAllocSizeCall(E)) &&(((isa<MemberExpr>(E) || tryUnwrapAllocSizeCall(E)) && "Unexpected type of invalid base") ? static_cast<void> (0) : __assert_fail ("(isa<MemberExpr>(E) || tryUnwrapAllocSizeCall(E)) && \"Unexpected type of invalid base\"" , "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 1534, __PRETTY_FUNCTION__)) |
| 1534 | "Unexpected type of invalid base")(((isa<MemberExpr>(E) || tryUnwrapAllocSizeCall(E)) && "Unexpected type of invalid base") ? static_cast<void> (0) : __assert_fail ("(isa<MemberExpr>(E) || tryUnwrapAllocSizeCall(E)) && \"Unexpected type of invalid base\"" , "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 1534, __PRETTY_FUNCTION__)); |
| 1535 | } |
| 1536 | #endif |
| 1537 | |
| 1538 | Base = B; |
| 1539 | Offset = CharUnits::fromQuantity(0); |
| 1540 | InvalidBase = BInvalid; |
| 1541 | Designator = SubobjectDesignator(getType(B)); |
| 1542 | IsNullPtr = false; |
| 1543 | } |
| 1544 | |
| 1545 | void setNull(ASTContext &Ctx, QualType PointerTy) { |
| 1546 | Base = (Expr *)nullptr; |
| 1547 | Offset = |
| 1548 | CharUnits::fromQuantity(Ctx.getTargetNullPointerValue(PointerTy)); |
| 1549 | InvalidBase = false; |
| 1550 | Designator = SubobjectDesignator(PointerTy->getPointeeType()); |
| 1551 | IsNullPtr = true; |
| 1552 | } |
| 1553 | |
| 1554 | void setInvalid(APValue::LValueBase B, unsigned I = 0) { |
| 1555 | set(B, true); |
| 1556 | } |
| 1557 | |
| 1558 | std::string toString(ASTContext &Ctx, QualType T) const { |
| 1559 | APValue Printable; |
| 1560 | moveInto(Printable); |
| 1561 | return Printable.getAsString(Ctx, T); |
| 1562 | } |
| 1563 | |
| 1564 | private: |
| 1565 | // Check that this LValue is not based on a null pointer. If it is, produce |
| 1566 | // a diagnostic and mark the designator as invalid. |
| 1567 | template <typename GenDiagType> |
| 1568 | bool checkNullPointerDiagnosingWith(const GenDiagType &GenDiag) { |
| 1569 | if (Designator.Invalid) |
| 1570 | return false; |
| 1571 | if (IsNullPtr) { |
| 1572 | GenDiag(); |
| 1573 | Designator.setInvalid(); |
| 1574 | return false; |
| 1575 | } |
| 1576 | return true; |
| 1577 | } |
| 1578 | |
| 1579 | public: |
| 1580 | bool checkNullPointer(EvalInfo &Info, const Expr *E, |
| 1581 | CheckSubobjectKind CSK) { |
| 1582 | return checkNullPointerDiagnosingWith([&Info, E, CSK] { |
| 1583 | Info.CCEDiag(E, diag::note_constexpr_null_subobject) << CSK; |
| 1584 | }); |
| 1585 | } |
| 1586 | |
| 1587 | bool checkNullPointerForFoldAccess(EvalInfo &Info, const Expr *E, |
| 1588 | AccessKinds AK) { |
| 1589 | return checkNullPointerDiagnosingWith([&Info, E, AK] { |
| 1590 | Info.FFDiag(E, diag::note_constexpr_access_null) << AK; |
| 1591 | }); |
| 1592 | } |
| 1593 | |
| 1594 | // Check this LValue refers to an object. If not, set the designator to be |
| 1595 | // invalid and emit a diagnostic. |
| 1596 | bool checkSubobject(EvalInfo &Info, const Expr *E, CheckSubobjectKind CSK) { |
| 1597 | return (CSK == CSK_ArrayToPointer || checkNullPointer(Info, E, CSK)) && |
| 1598 | Designator.checkSubobject(Info, E, CSK); |
| 1599 | } |
| 1600 | |
| 1601 | void addDecl(EvalInfo &Info, const Expr *E, |
| 1602 | const Decl *D, bool Virtual = false) { |
| 1603 | if (checkSubobject(Info, E, isa<FieldDecl>(D) ? CSK_Field : CSK_Base)) |
| 1604 | Designator.addDeclUnchecked(D, Virtual); |
| 1605 | } |
| 1606 | void addUnsizedArray(EvalInfo &Info, const Expr *E, QualType ElemTy) { |
| 1607 | if (!Designator.Entries.empty()) { |
| 1608 | Info.CCEDiag(E, diag::note_constexpr_unsupported_unsized_array); |
| 1609 | Designator.setInvalid(); |
| 1610 | return; |
| 1611 | } |
| 1612 | if (checkSubobject(Info, E, CSK_ArrayToPointer)) { |
| 1613 | assert(getType(Base)->isPointerType() || getType(Base)->isArrayType())((getType(Base)->isPointerType() || getType(Base)->isArrayType ()) ? static_cast<void> (0) : __assert_fail ("getType(Base)->isPointerType() || getType(Base)->isArrayType()" , "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 1613, __PRETTY_FUNCTION__)); |
| 1614 | Designator.FirstEntryIsAnUnsizedArray = true; |
| 1615 | Designator.addUnsizedArrayUnchecked(ElemTy); |
| 1616 | } |
| 1617 | } |
| 1618 | void addArray(EvalInfo &Info, const Expr *E, const ConstantArrayType *CAT) { |
| 1619 | if (checkSubobject(Info, E, CSK_ArrayToPointer)) |
| 1620 | Designator.addArrayUnchecked(CAT); |
| 1621 | } |
| 1622 | void addComplex(EvalInfo &Info, const Expr *E, QualType EltTy, bool Imag) { |
| 1623 | if (checkSubobject(Info, E, Imag ? CSK_Imag : CSK_Real)) |
| 1624 | Designator.addComplexUnchecked(EltTy, Imag); |
| 1625 | } |
| 1626 | void clearIsNullPointer() { |
| 1627 | IsNullPtr = false; |
| 1628 | } |
| 1629 | void adjustOffsetAndIndex(EvalInfo &Info, const Expr *E, |
| 1630 | const APSInt &Index, CharUnits ElementSize) { |
| 1631 | // An index of 0 has no effect. (In C, adding 0 to a null pointer is UB, |
| 1632 | // but we're not required to diagnose it and it's valid in C++.) |
| 1633 | if (!Index) |
| 1634 | return; |
| 1635 | |
| 1636 | // Compute the new offset in the appropriate width, wrapping at 64 bits. |
| 1637 | // FIXME: When compiling for a 32-bit target, we should use 32-bit |
| 1638 | // offsets. |
| 1639 | uint64_t Offset64 = Offset.getQuantity(); |
| 1640 | uint64_t ElemSize64 = ElementSize.getQuantity(); |
| 1641 | uint64_t Index64 = Index.extOrTrunc(64).getZExtValue(); |
| 1642 | Offset = CharUnits::fromQuantity(Offset64 + ElemSize64 * Index64); |
| 1643 | |
| 1644 | if (checkNullPointer(Info, E, CSK_ArrayIndex)) |
| 1645 | Designator.adjustIndex(Info, E, Index); |
| 1646 | clearIsNullPointer(); |
| 1647 | } |
| 1648 | void adjustOffset(CharUnits N) { |
| 1649 | Offset += N; |
| 1650 | if (N.getQuantity()) |
| 1651 | clearIsNullPointer(); |
| 1652 | } |
| 1653 | }; |
| 1654 | |
| 1655 | struct MemberPtr { |
| 1656 | MemberPtr() {} |
| 1657 | explicit MemberPtr(const ValueDecl *Decl) : |
| 1658 | DeclAndIsDerivedMember(Decl, false), Path() {} |
| 1659 | |
| 1660 | /// The member or (direct or indirect) field referred to by this member |
| 1661 | /// pointer, or 0 if this is a null member pointer. |
| 1662 | const ValueDecl *getDecl() const { |
| 1663 | return DeclAndIsDerivedMember.getPointer(); |
| 1664 | } |
| 1665 | /// Is this actually a member of some type derived from the relevant class? |
| 1666 | bool isDerivedMember() const { |
| 1667 | return DeclAndIsDerivedMember.getInt(); |
| 1668 | } |
| 1669 | /// Get the class which the declaration actually lives in. |
| 1670 | const CXXRecordDecl *getContainingRecord() const { |
| 1671 | return cast<CXXRecordDecl>( |
| 1672 | DeclAndIsDerivedMember.getPointer()->getDeclContext()); |
| 1673 | } |
| 1674 | |
| 1675 | void moveInto(APValue &V) const { |
| 1676 | V = APValue(getDecl(), isDerivedMember(), Path); |
| 1677 | } |
| 1678 | void setFrom(const APValue &V) { |
| 1679 | assert(V.isMemberPointer())((V.isMemberPointer()) ? static_cast<void> (0) : __assert_fail ("V.isMemberPointer()", "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 1679, __PRETTY_FUNCTION__)); |
| 1680 | DeclAndIsDerivedMember.setPointer(V.getMemberPointerDecl()); |
| 1681 | DeclAndIsDerivedMember.setInt(V.isMemberPointerToDerivedMember()); |
| 1682 | Path.clear(); |
| 1683 | ArrayRef<const CXXRecordDecl*> P = V.getMemberPointerPath(); |
| 1684 | Path.insert(Path.end(), P.begin(), P.end()); |
| 1685 | } |
| 1686 | |
| 1687 | /// DeclAndIsDerivedMember - The member declaration, and a flag indicating |
| 1688 | /// whether the member is a member of some class derived from the class type |
| 1689 | /// of the member pointer. |
| 1690 | llvm::PointerIntPair<const ValueDecl*, 1, bool> DeclAndIsDerivedMember; |
| 1691 | /// Path - The path of base/derived classes from the member declaration's |
| 1692 | /// class (exclusive) to the class type of the member pointer (inclusive). |
| 1693 | SmallVector<const CXXRecordDecl*, 4> Path; |
| 1694 | |
| 1695 | /// Perform a cast towards the class of the Decl (either up or down the |
| 1696 | /// hierarchy). |
| 1697 | bool castBack(const CXXRecordDecl *Class) { |
| 1698 | assert(!Path.empty())((!Path.empty()) ? static_cast<void> (0) : __assert_fail ("!Path.empty()", "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 1698, __PRETTY_FUNCTION__)); |
| 1699 | const CXXRecordDecl *Expected; |
| 1700 | if (Path.size() >= 2) |
| 1701 | Expected = Path[Path.size() - 2]; |
| 1702 | else |
| 1703 | Expected = getContainingRecord(); |
| 1704 | if (Expected->getCanonicalDecl() != Class->getCanonicalDecl()) { |
| 1705 | // C++11 [expr.static.cast]p12: In a conversion from (D::*) to (B::*), |
| 1706 | // if B does not contain the original member and is not a base or |
| 1707 | // derived class of the class containing the original member, the result |
| 1708 | // of the cast is undefined. |
| 1709 | // C++11 [conv.mem]p2 does not cover this case for a cast from (B::*) to |
| 1710 | // (D::*). We consider that to be a language defect. |
| 1711 | return false; |
| 1712 | } |
| 1713 | Path.pop_back(); |
| 1714 | return true; |
| 1715 | } |
| 1716 | /// Perform a base-to-derived member pointer cast. |
| 1717 | bool castToDerived(const CXXRecordDecl *Derived) { |
| 1718 | if (!getDecl()) |
| 1719 | return true; |
| 1720 | if (!isDerivedMember()) { |
| 1721 | Path.push_back(Derived); |
| 1722 | return true; |
| 1723 | } |
| 1724 | if (!castBack(Derived)) |
| 1725 | return false; |
| 1726 | if (Path.empty()) |
| 1727 | DeclAndIsDerivedMember.setInt(false); |
| 1728 | return true; |
| 1729 | } |
| 1730 | /// Perform a derived-to-base member pointer cast. |
| 1731 | bool castToBase(const CXXRecordDecl *Base) { |
| 1732 | if (!getDecl()) |
| 1733 | return true; |
| 1734 | if (Path.empty()) |
| 1735 | DeclAndIsDerivedMember.setInt(true); |
| 1736 | if (isDerivedMember()) { |
| 1737 | Path.push_back(Base); |
| 1738 | return true; |
| 1739 | } |
| 1740 | return castBack(Base); |
| 1741 | } |
| 1742 | }; |
| 1743 | |
| 1744 | /// Compare two member pointers, which are assumed to be of the same type. |
| 1745 | static bool operator==(const MemberPtr &LHS, const MemberPtr &RHS) { |
| 1746 | if (!LHS.getDecl() || !RHS.getDecl()) |
| 1747 | return !LHS.getDecl() && !RHS.getDecl(); |
| 1748 | if (LHS.getDecl()->getCanonicalDecl() != RHS.getDecl()->getCanonicalDecl()) |
| 1749 | return false; |
| 1750 | return LHS.Path == RHS.Path; |
| 1751 | } |
| 1752 | } |
| 1753 | |
| 1754 | static bool Evaluate(APValue &Result, EvalInfo &Info, const Expr *E); |
| 1755 | static bool EvaluateInPlace(APValue &Result, EvalInfo &Info, |
| 1756 | const LValue &This, const Expr *E, |
| 1757 | bool AllowNonLiteralTypes = false); |
| 1758 | static bool EvaluateLValue(const Expr *E, LValue &Result, EvalInfo &Info, |
| 1759 | bool InvalidBaseOK = false); |
| 1760 | static bool EvaluatePointer(const Expr *E, LValue &Result, EvalInfo &Info, |
| 1761 | bool InvalidBaseOK = false); |
| 1762 | static bool EvaluateMemberPointer(const Expr *E, MemberPtr &Result, |
| 1763 | EvalInfo &Info); |
| 1764 | static bool EvaluateTemporary(const Expr *E, LValue &Result, EvalInfo &Info); |
| 1765 | static bool EvaluateInteger(const Expr *E, APSInt &Result, EvalInfo &Info); |
| 1766 | static bool EvaluateIntegerOrLValue(const Expr *E, APValue &Result, |
| 1767 | EvalInfo &Info); |
| 1768 | static bool EvaluateFloat(const Expr *E, APFloat &Result, EvalInfo &Info); |
| 1769 | static bool EvaluateComplex(const Expr *E, ComplexValue &Res, EvalInfo &Info); |
| 1770 | static bool EvaluateAtomic(const Expr *E, const LValue *This, APValue &Result, |
| 1771 | EvalInfo &Info); |
| 1772 | static bool EvaluateAsRValue(EvalInfo &Info, const Expr *E, APValue &Result); |
| 1773 | |
| 1774 | /// Evaluate an integer or fixed point expression into an APResult. |
| 1775 | static bool EvaluateFixedPointOrInteger(const Expr *E, APFixedPoint &Result, |
| 1776 | EvalInfo &Info); |
| 1777 | |
| 1778 | /// Evaluate only a fixed point expression into an APResult. |
| 1779 | static bool EvaluateFixedPoint(const Expr *E, APFixedPoint &Result, |
| 1780 | EvalInfo &Info); |
| 1781 | |
| 1782 | //===----------------------------------------------------------------------===// |
| 1783 | // Misc utilities |
| 1784 | //===----------------------------------------------------------------------===// |
| 1785 | |
| 1786 | /// Negate an APSInt in place, converting it to a signed form if necessary, and |
| 1787 | /// preserving its value (by extending by up to one bit as needed). |
| 1788 | static void negateAsSigned(APSInt &Int) { |
| 1789 | if (Int.isUnsigned() || Int.isMinSignedValue()) { |
| 1790 | Int = Int.extend(Int.getBitWidth() + 1); |
| 1791 | Int.setIsSigned(true); |
| 1792 | } |
| 1793 | Int = -Int; |
| 1794 | } |
| 1795 | |
| 1796 | template<typename KeyT> |
| 1797 | APValue &CallStackFrame::createTemporary(const KeyT *Key, QualType T, |
| 1798 | bool IsLifetimeExtended, LValue &LV) { |
| 1799 | unsigned Version = getTempVersion(); |
| 1800 | APValue::LValueBase Base(Key, Index, Version); |
| 1801 | LV.set(Base); |
| 1802 | APValue &Result = Temporaries[MapKeyTy(Key, Version)]; |
| 1803 | assert(Result.isAbsent() && "temporary created multiple times")((Result.isAbsent() && "temporary created multiple times" ) ? static_cast<void> (0) : __assert_fail ("Result.isAbsent() && \"temporary created multiple times\"" , "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 1803, __PRETTY_FUNCTION__)); |
| 1804 | |
| 1805 | // If we're creating a temporary immediately in the operand of a speculative |
| 1806 | // evaluation, don't register a cleanup to be run outside the speculative |
| 1807 | // evaluation context, since we won't actually be able to initialize this |
| 1808 | // object. |
| 1809 | if (Index <= Info.SpeculativeEvaluationDepth) { |
| 1810 | if (T.isDestructedType()) |
| 1811 | Info.noteSideEffect(); |
| 1812 | } else { |
| 1813 | Info.CleanupStack.push_back(Cleanup(&Result, Base, T, IsLifetimeExtended)); |
| 1814 | } |
| 1815 | return Result; |
| 1816 | } |
| 1817 | |
| 1818 | APValue *EvalInfo::createHeapAlloc(const Expr *E, QualType T, LValue &LV) { |
| 1819 | if (NumHeapAllocs > DynamicAllocLValue::getMaxIndex()) { |
| 1820 | FFDiag(E, diag::note_constexpr_heap_alloc_limit_exceeded); |
| 1821 | return nullptr; |
| 1822 | } |
| 1823 | |
| 1824 | DynamicAllocLValue DA(NumHeapAllocs++); |
| 1825 | LV.set(APValue::LValueBase::getDynamicAlloc(DA, T)); |
| 1826 | auto Result = HeapAllocs.emplace(std::piecewise_construct, |
| 1827 | std::forward_as_tuple(DA), std::tuple<>()); |
| 1828 | assert(Result.second && "reused a heap alloc index?")((Result.second && "reused a heap alloc index?") ? static_cast <void> (0) : __assert_fail ("Result.second && \"reused a heap alloc index?\"" , "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 1828, __PRETTY_FUNCTION__)); |
| 1829 | Result.first->second.AllocExpr = E; |
| 1830 | return &Result.first->second.Value; |
| 1831 | } |
| 1832 | |
| 1833 | /// Produce a string describing the given constexpr call. |
| 1834 | void CallStackFrame::describe(raw_ostream &Out) { |
| 1835 | unsigned ArgIndex = 0; |
| 1836 | bool IsMemberCall = isa<CXXMethodDecl>(Callee) && |
| 1837 | !isa<CXXConstructorDecl>(Callee) && |
| 1838 | cast<CXXMethodDecl>(Callee)->isInstance(); |
| 1839 | |
| 1840 | if (!IsMemberCall) |
| 1841 | Out << *Callee << '('; |
| 1842 | |
| 1843 | if (This && IsMemberCall) { |
| 1844 | APValue Val; |
| 1845 | This->moveInto(Val); |
| 1846 | Val.printPretty(Out, Info.Ctx, |
| 1847 | This->Designator.MostDerivedType); |
| 1848 | // FIXME: Add parens around Val if needed. |
| 1849 | Out << "->" << *Callee << '('; |
| 1850 | IsMemberCall = false; |
| 1851 | } |
| 1852 | |
| 1853 | for (FunctionDecl::param_const_iterator I = Callee->param_begin(), |
| 1854 | E = Callee->param_end(); I != E; ++I, ++ArgIndex) { |
| 1855 | if (ArgIndex > (unsigned)IsMemberCall) |
| 1856 | Out << ", "; |
| 1857 | |
| 1858 | const ParmVarDecl *Param = *I; |
| 1859 | const APValue &Arg = Arguments[ArgIndex]; |
| 1860 | Arg.printPretty(Out, Info.Ctx, Param->getType()); |
| 1861 | |
| 1862 | if (ArgIndex == 0 && IsMemberCall) |
| 1863 | Out << "->" << *Callee << '('; |
| 1864 | } |
| 1865 | |
| 1866 | Out << ')'; |
| 1867 | } |
| 1868 | |
| 1869 | /// Evaluate an expression to see if it had side-effects, and discard its |
| 1870 | /// result. |
| 1871 | /// \return \c true if the caller should keep evaluating. |
| 1872 | static bool EvaluateIgnoredValue(EvalInfo &Info, const Expr *E) { |
| 1873 | APValue Scratch; |
| 1874 | if (!Evaluate(Scratch, Info, E)) |
| 1875 | // We don't need the value, but we might have skipped a side effect here. |
| 1876 | return Info.noteSideEffect(); |
| 1877 | return true; |
| 1878 | } |
| 1879 | |
| 1880 | /// Should this call expression be treated as a string literal? |
| 1881 | static bool IsStringLiteralCall(const CallExpr *E) { |
| 1882 | unsigned Builtin = E->getBuiltinCallee(); |
| 1883 | return (Builtin == Builtin::BI__builtin___CFStringMakeConstantString || |
| 1884 | Builtin == Builtin::BI__builtin___NSStringMakeConstantString); |
| 1885 | } |
| 1886 | |
| 1887 | static bool IsGlobalLValue(APValue::LValueBase B) { |
| 1888 | // C++11 [expr.const]p3 An address constant expression is a prvalue core |
| 1889 | // constant expression of pointer type that evaluates to... |
| 1890 | |
| 1891 | // ... a null pointer value, or a prvalue core constant expression of type |
| 1892 | // std::nullptr_t. |
| 1893 | if (!B) return true; |
| 1894 | |
| 1895 | if (const ValueDecl *D = B.dyn_cast<const ValueDecl*>()) { |
| 1896 | // ... the address of an object with static storage duration, |
| 1897 | if (const VarDecl *VD = dyn_cast<VarDecl>(D)) |
| 1898 | return VD->hasGlobalStorage(); |
| 1899 | // ... the address of a function, |
| 1900 | // ... the address of a GUID [MS extension], |
| 1901 | return isa<FunctionDecl>(D) || isa<MSGuidDecl>(D); |
| 1902 | } |
| 1903 | |
| 1904 | if (B.is<TypeInfoLValue>() || B.is<DynamicAllocLValue>()) |
| 1905 | return true; |
| 1906 | |
| 1907 | const Expr *E = B.get<const Expr*>(); |
| 1908 | switch (E->getStmtClass()) { |
| 1909 | default: |
| 1910 | return false; |
| 1911 | case Expr::CompoundLiteralExprClass: { |
| 1912 | const CompoundLiteralExpr *CLE = cast<CompoundLiteralExpr>(E); |
| 1913 | return CLE->isFileScope() && CLE->isLValue(); |
| 1914 | } |
| 1915 | case Expr::MaterializeTemporaryExprClass: |
| 1916 | // A materialized temporary might have been lifetime-extended to static |
| 1917 | // storage duration. |
| 1918 | return cast<MaterializeTemporaryExpr>(E)->getStorageDuration() == SD_Static; |
| 1919 | // A string literal has static storage duration. |
| 1920 | case Expr::StringLiteralClass: |
| 1921 | case Expr::PredefinedExprClass: |
| 1922 | case Expr::ObjCStringLiteralClass: |
| 1923 | case Expr::ObjCEncodeExprClass: |
| 1924 | return true; |
| 1925 | case Expr::ObjCBoxedExprClass: |
| 1926 | return cast<ObjCBoxedExpr>(E)->isExpressibleAsConstantInitializer(); |
| 1927 | case Expr::CallExprClass: |
| 1928 | return IsStringLiteralCall(cast<CallExpr>(E)); |
| 1929 | // For GCC compatibility, &&label has static storage duration. |
| 1930 | case Expr::AddrLabelExprClass: |
| 1931 | return true; |
| 1932 | // A Block literal expression may be used as the initialization value for |
| 1933 | // Block variables at global or local static scope. |
| 1934 | case Expr::BlockExprClass: |
| 1935 | return !cast<BlockExpr>(E)->getBlockDecl()->hasCaptures(); |
| 1936 | case Expr::ImplicitValueInitExprClass: |
| 1937 | // FIXME: |
| 1938 | // We can never form an lvalue with an implicit value initialization as its |
| 1939 | // base through expression evaluation, so these only appear in one case: the |
| 1940 | // implicit variable declaration we invent when checking whether a constexpr |
| 1941 | // constructor can produce a constant expression. We must assume that such |
| 1942 | // an expression might be a global lvalue. |
| 1943 | return true; |
| 1944 | } |
| 1945 | } |
| 1946 | |
| 1947 | static const ValueDecl *GetLValueBaseDecl(const LValue &LVal) { |
| 1948 | return LVal.Base.dyn_cast<const ValueDecl*>(); |
| 1949 | } |
| 1950 | |
| 1951 | static bool IsLiteralLValue(const LValue &Value) { |
| 1952 | if (Value.getLValueCallIndex()) |
| 1953 | return false; |
| 1954 | const Expr *E = Value.Base.dyn_cast<const Expr*>(); |
| 1955 | return E && !isa<MaterializeTemporaryExpr>(E); |
| 1956 | } |
| 1957 | |
| 1958 | static bool IsWeakLValue(const LValue &Value) { |
| 1959 | const ValueDecl *Decl = GetLValueBaseDecl(Value); |
| 1960 | return Decl && Decl->isWeak(); |
| 1961 | } |
| 1962 | |
| 1963 | static bool isZeroSized(const LValue &Value) { |
| 1964 | const ValueDecl *Decl = GetLValueBaseDecl(Value); |
| 1965 | if (Decl && isa<VarDecl>(Decl)) { |
| 1966 | QualType Ty = Decl->getType(); |
| 1967 | if (Ty->isArrayType()) |
| 1968 | return Ty->isIncompleteType() || |
| 1969 | Decl->getASTContext().getTypeSize(Ty) == 0; |
| 1970 | } |
| 1971 | return false; |
| 1972 | } |
| 1973 | |
| 1974 | static bool HasSameBase(const LValue &A, const LValue &B) { |
| 1975 | if (!A.getLValueBase()) |
| 1976 | return !B.getLValueBase(); |
| 1977 | if (!B.getLValueBase()) |
| 1978 | return false; |
| 1979 | |
| 1980 | if (A.getLValueBase().getOpaqueValue() != |
| 1981 | B.getLValueBase().getOpaqueValue()) { |
| 1982 | const Decl *ADecl = GetLValueBaseDecl(A); |
| 1983 | if (!ADecl) |
| 1984 | return false; |
| 1985 | const Decl *BDecl = GetLValueBaseDecl(B); |
| 1986 | if (!BDecl || ADecl->getCanonicalDecl() != BDecl->getCanonicalDecl()) |
| 1987 | return false; |
| 1988 | } |
| 1989 | |
| 1990 | return IsGlobalLValue(A.getLValueBase()) || |
| 1991 | (A.getLValueCallIndex() == B.getLValueCallIndex() && |
| 1992 | A.getLValueVersion() == B.getLValueVersion()); |
| 1993 | } |
| 1994 | |
| 1995 | static void NoteLValueLocation(EvalInfo &Info, APValue::LValueBase Base) { |
| 1996 | assert(Base && "no location for a null lvalue")((Base && "no location for a null lvalue") ? static_cast <void> (0) : __assert_fail ("Base && \"no location for a null lvalue\"" , "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 1996, __PRETTY_FUNCTION__)); |
| 1997 | const ValueDecl *VD = Base.dyn_cast<const ValueDecl*>(); |
| 1998 | if (VD) |
| 1999 | Info.Note(VD->getLocation(), diag::note_declared_at); |
| 2000 | else if (const Expr *E = Base.dyn_cast<const Expr*>()) |
| 2001 | Info.Note(E->getExprLoc(), diag::note_constexpr_temporary_here); |
| 2002 | else if (DynamicAllocLValue DA = Base.dyn_cast<DynamicAllocLValue>()) { |
| 2003 | // FIXME: Produce a note for dangling pointers too. |
| 2004 | if (Optional<DynAlloc*> Alloc = Info.lookupDynamicAlloc(DA)) |
| 2005 | Info.Note((*Alloc)->AllocExpr->getExprLoc(), |
| 2006 | diag::note_constexpr_dynamic_alloc_here); |
| 2007 | } |
| 2008 | // We have no information to show for a typeid(T) object. |
| 2009 | } |
| 2010 | |
| 2011 | enum class CheckEvaluationResultKind { |
| 2012 | ConstantExpression, |
| 2013 | FullyInitialized, |
| 2014 | }; |
| 2015 | |
| 2016 | /// Materialized temporaries that we've already checked to determine if they're |
| 2017 | /// initializsed by a constant expression. |
| 2018 | using CheckedTemporaries = |
| 2019 | llvm::SmallPtrSet<const MaterializeTemporaryExpr *, 8>; |
| 2020 | |
| 2021 | static bool CheckEvaluationResult(CheckEvaluationResultKind CERK, |
| 2022 | EvalInfo &Info, SourceLocation DiagLoc, |
| 2023 | QualType Type, const APValue &Value, |
| 2024 | Expr::ConstExprUsage Usage, |
| 2025 | SourceLocation SubobjectLoc, |
| 2026 | CheckedTemporaries &CheckedTemps); |
| 2027 | |
| 2028 | /// Check that this reference or pointer core constant expression is a valid |
| 2029 | /// value for an address or reference constant expression. Return true if we |
| 2030 | /// can fold this expression, whether or not it's a constant expression. |
| 2031 | static bool CheckLValueConstantExpression(EvalInfo &Info, SourceLocation Loc, |
| 2032 | QualType Type, const LValue &LVal, |
| 2033 | Expr::ConstExprUsage Usage, |
| 2034 | CheckedTemporaries &CheckedTemps) { |
| 2035 | bool IsReferenceType = Type->isReferenceType(); |
| 2036 | |
| 2037 | APValue::LValueBase Base = LVal.getLValueBase(); |
| 2038 | const SubobjectDesignator &Designator = LVal.getLValueDesignator(); |
| 2039 | |
| 2040 | if (auto *VD = LVal.getLValueBase().dyn_cast<const ValueDecl *>()) { |
| 2041 | if (auto *FD = dyn_cast<FunctionDecl>(VD)) { |
| 2042 | if (FD->isConsteval()) { |
| 2043 | Info.FFDiag(Loc, diag::note_consteval_address_accessible) |
| 2044 | << !Type->isAnyPointerType(); |
| 2045 | Info.Note(FD->getLocation(), diag::note_declared_at); |
| 2046 | return false; |
| 2047 | } |
| 2048 | } |
| 2049 | } |
| 2050 | |
| 2051 | // Check that the object is a global. Note that the fake 'this' object we |
| 2052 | // manufacture when checking potential constant expressions is conservatively |
| 2053 | // assumed to be global here. |
| 2054 | if (!IsGlobalLValue(Base)) { |
| 2055 | if (Info.getLangOpts().CPlusPlus11) { |
| 2056 | const ValueDecl *VD = Base.dyn_cast<const ValueDecl*>(); |
| 2057 | Info.FFDiag(Loc, diag::note_constexpr_non_global, 1) |
| 2058 | << IsReferenceType << !Designator.Entries.empty() |
| 2059 | << !!VD << VD; |
| 2060 | |
| 2061 | auto *VarD = dyn_cast_or_null<VarDecl>(VD); |
| 2062 | if (VarD && VarD->isConstexpr()) { |
| 2063 | // Non-static local constexpr variables have unintuitive semantics: |
| 2064 | // constexpr int a = 1; |
| 2065 | // constexpr const int *p = &a; |
| 2066 | // ... is invalid because the address of 'a' is not constant. Suggest |
| 2067 | // adding a 'static' in this case. |
| 2068 | Info.Note(VarD->getLocation(), diag::note_constexpr_not_static) |
| 2069 | << VarD |
| 2070 | << FixItHint::CreateInsertion(VarD->getBeginLoc(), "static "); |
| 2071 | } else { |
| 2072 | NoteLValueLocation(Info, Base); |
| 2073 | } |
| 2074 | } else { |
| 2075 | Info.FFDiag(Loc); |
| 2076 | } |
| 2077 | // Don't allow references to temporaries to escape. |
| 2078 | return false; |
| 2079 | } |
| 2080 | assert((Info.checkingPotentialConstantExpression() ||(((Info.checkingPotentialConstantExpression() || LVal.getLValueCallIndex () == 0) && "have call index for global lvalue") ? static_cast <void> (0) : __assert_fail ("(Info.checkingPotentialConstantExpression() || LVal.getLValueCallIndex() == 0) && \"have call index for global lvalue\"" , "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 2082, __PRETTY_FUNCTION__)) |
| 2081 | LVal.getLValueCallIndex() == 0) &&(((Info.checkingPotentialConstantExpression() || LVal.getLValueCallIndex () == 0) && "have call index for global lvalue") ? static_cast <void> (0) : __assert_fail ("(Info.checkingPotentialConstantExpression() || LVal.getLValueCallIndex() == 0) && \"have call index for global lvalue\"" , "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 2082, __PRETTY_FUNCTION__)) |
| 2082 | "have call index for global lvalue")(((Info.checkingPotentialConstantExpression() || LVal.getLValueCallIndex () == 0) && "have call index for global lvalue") ? static_cast <void> (0) : __assert_fail ("(Info.checkingPotentialConstantExpression() || LVal.getLValueCallIndex() == 0) && \"have call index for global lvalue\"" , "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 2082, __PRETTY_FUNCTION__)); |
| 2083 | |
| 2084 | if (Base.is<DynamicAllocLValue>()) { |
| 2085 | Info.FFDiag(Loc, diag::note_constexpr_dynamic_alloc) |
| 2086 | << IsReferenceType << !Designator.Entries.empty(); |
| 2087 | NoteLValueLocation(Info, Base); |
| 2088 | return false; |
| 2089 | } |
| 2090 | |
| 2091 | if (const ValueDecl *VD = Base.dyn_cast<const ValueDecl*>()) { |
| 2092 | if (const VarDecl *Var = dyn_cast<const VarDecl>(VD)) { |
| 2093 | // Check if this is a thread-local variable. |
| 2094 | if (Var->getTLSKind()) |
| 2095 | // FIXME: Diagnostic! |
| 2096 | return false; |
| 2097 | |
| 2098 | // A dllimport variable never acts like a constant. |
| 2099 | if (Usage == Expr::EvaluateForCodeGen && Var->hasAttr<DLLImportAttr>()) |
| 2100 | // FIXME: Diagnostic! |
| 2101 | return false; |
| 2102 | } |
| 2103 | if (const auto *FD = dyn_cast<const FunctionDecl>(VD)) { |
| 2104 | // __declspec(dllimport) must be handled very carefully: |
| 2105 | // We must never initialize an expression with the thunk in C++. |
| 2106 | // Doing otherwise would allow the same id-expression to yield |
| 2107 | // different addresses for the same function in different translation |
| 2108 | // units. However, this means that we must dynamically initialize the |
| 2109 | // expression with the contents of the import address table at runtime. |
| 2110 | // |
| 2111 | // The C language has no notion of ODR; furthermore, it has no notion of |
| 2112 | // dynamic initialization. This means that we are permitted to |
| 2113 | // perform initialization with the address of the thunk. |
| 2114 | if (Info.getLangOpts().CPlusPlus && Usage == Expr::EvaluateForCodeGen && |
| 2115 | FD->hasAttr<DLLImportAttr>()) |
| 2116 | // FIXME: Diagnostic! |
| 2117 | return false; |
| 2118 | } |
| 2119 | } else if (const auto *MTE = dyn_cast_or_null<MaterializeTemporaryExpr>( |
| 2120 | Base.dyn_cast<const Expr *>())) { |
| 2121 | if (CheckedTemps.insert(MTE).second) { |
| 2122 | QualType TempType = getType(Base); |
| 2123 | if (TempType.isDestructedType()) { |
| 2124 | Info.FFDiag(MTE->getExprLoc(), |
| 2125 | diag::note_constexpr_unsupported_tempoarary_nontrivial_dtor) |
| 2126 | << TempType; |
| 2127 | return false; |
| 2128 | } |
| 2129 | |
| 2130 | APValue *V = MTE->getOrCreateValue(false); |
| 2131 | assert(V && "evasluation result refers to uninitialised temporary")((V && "evasluation result refers to uninitialised temporary" ) ? static_cast<void> (0) : __assert_fail ("V && \"evasluation result refers to uninitialised temporary\"" , "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 2131, __PRETTY_FUNCTION__)); |
| 2132 | if (!CheckEvaluationResult(CheckEvaluationResultKind::ConstantExpression, |
| 2133 | Info, MTE->getExprLoc(), TempType, *V, |
| 2134 | Usage, SourceLocation(), CheckedTemps)) |
| 2135 | return false; |
| 2136 | } |
| 2137 | } |
| 2138 | |
| 2139 | // Allow address constant expressions to be past-the-end pointers. This is |
| 2140 | // an extension: the standard requires them to point to an object. |
| 2141 | if (!IsReferenceType) |
| 2142 | return true; |
| 2143 | |
| 2144 | // A reference constant expression must refer to an object. |
| 2145 | if (!Base) { |
| 2146 | // FIXME: diagnostic |
| 2147 | Info.CCEDiag(Loc); |
| 2148 | return true; |
| 2149 | } |
| 2150 | |
| 2151 | // Does this refer one past the end of some object? |
| 2152 | if (!Designator.Invalid && Designator.isOnePastTheEnd()) { |
| 2153 | const ValueDecl *VD = Base.dyn_cast<const ValueDecl*>(); |
| 2154 | Info.FFDiag(Loc, diag::note_constexpr_past_end, 1) |
| 2155 | << !Designator.Entries.empty() << !!VD << VD; |
| 2156 | NoteLValueLocation(Info, Base); |
| 2157 | } |
| 2158 | |
| 2159 | return true; |
| 2160 | } |
| 2161 | |
| 2162 | /// Member pointers are constant expressions unless they point to a |
| 2163 | /// non-virtual dllimport member function. |
| 2164 | static bool CheckMemberPointerConstantExpression(EvalInfo &Info, |
| 2165 | SourceLocation Loc, |
| 2166 | QualType Type, |
| 2167 | const APValue &Value, |
| 2168 | Expr::ConstExprUsage Usage) { |
| 2169 | const ValueDecl *Member = Value.getMemberPointerDecl(); |
| 2170 | const auto *FD = dyn_cast_or_null<CXXMethodDecl>(Member); |
| 2171 | if (!FD) |
| 2172 | return true; |
| 2173 | if (FD->isConsteval()) { |
| 2174 | Info.FFDiag(Loc, diag::note_consteval_address_accessible) << /*pointer*/ 0; |
| 2175 | Info.Note(FD->getLocation(), diag::note_declared_at); |
| 2176 | return false; |
| 2177 | } |
| 2178 | return Usage == Expr::EvaluateForMangling || FD->isVirtual() || |
| 2179 | !FD->hasAttr<DLLImportAttr>(); |
| 2180 | } |
| 2181 | |
| 2182 | /// Check that this core constant expression is of literal type, and if not, |
| 2183 | /// produce an appropriate diagnostic. |
| 2184 | static bool CheckLiteralType(EvalInfo &Info, const Expr *E, |
| 2185 | const LValue *This = nullptr) { |
| 2186 | if (!E->isRValue() || E->getType()->isLiteralType(Info.Ctx)) |
| 2187 | return true; |
| 2188 | |
| 2189 | // C++1y: A constant initializer for an object o [...] may also invoke |
| 2190 | // constexpr constructors for o and its subobjects even if those objects |
| 2191 | // are of non-literal class types. |
| 2192 | // |
| 2193 | // C++11 missed this detail for aggregates, so classes like this: |
| 2194 | // struct foo_t { union { int i; volatile int j; } u; }; |
| 2195 | // are not (obviously) initializable like so: |
| 2196 | // __attribute__((__require_constant_initialization__)) |
| 2197 | // static const foo_t x = {{0}}; |
| 2198 | // because "i" is a subobject with non-literal initialization (due to the |
| 2199 | // volatile member of the union). See: |
| 2200 | // http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#1677 |
| 2201 | // Therefore, we use the C++1y behavior. |
| 2202 | if (This && Info.EvaluatingDecl == This->getLValueBase()) |
| 2203 | return true; |
| 2204 | |
| 2205 | // Prvalue constant expressions must be of literal types. |
| 2206 | if (Info.getLangOpts().CPlusPlus11) |
| 2207 | Info.FFDiag(E, diag::note_constexpr_nonliteral) |
| 2208 | << E->getType(); |
| 2209 | else |
| 2210 | Info.FFDiag(E, diag::note_invalid_subexpr_in_const_expr); |
| 2211 | return false; |
| 2212 | } |
| 2213 | |
| 2214 | static bool CheckEvaluationResult(CheckEvaluationResultKind CERK, |
| 2215 | EvalInfo &Info, SourceLocation DiagLoc, |
| 2216 | QualType Type, const APValue &Value, |
| 2217 | Expr::ConstExprUsage Usage, |
| 2218 | SourceLocation SubobjectLoc, |
| 2219 | CheckedTemporaries &CheckedTemps) { |
| 2220 | if (!Value.hasValue()) { |
| 2221 | Info.FFDiag(DiagLoc, diag::note_constexpr_uninitialized) |
| 2222 | << true << Type; |
| 2223 | if (SubobjectLoc.isValid()) |
| 2224 | Info.Note(SubobjectLoc, diag::note_constexpr_subobject_declared_here); |
| 2225 | return false; |
| 2226 | } |
| 2227 | |
| 2228 | // We allow _Atomic(T) to be initialized from anything that T can be |
| 2229 | // initialized from. |
| 2230 | if (const AtomicType *AT = Type->getAs<AtomicType>()) |
| 2231 | Type = AT->getValueType(); |
| 2232 | |
| 2233 | // Core issue 1454: For a literal constant expression of array or class type, |
| 2234 | // each subobject of its value shall have been initialized by a constant |
| 2235 | // expression. |
| 2236 | if (Value.isArray()) { |
| 2237 | QualType EltTy = Type->castAsArrayTypeUnsafe()->getElementType(); |
| 2238 | for (unsigned I = 0, N = Value.getArrayInitializedElts(); I != N; ++I) { |
| 2239 | if (!CheckEvaluationResult(CERK, Info, DiagLoc, EltTy, |
| 2240 | Value.getArrayInitializedElt(I), Usage, |
| 2241 | SubobjectLoc, CheckedTemps)) |
| 2242 | return false; |
| 2243 | } |
| 2244 | if (!Value.hasArrayFiller()) |
| 2245 | return true; |
| 2246 | return CheckEvaluationResult(CERK, Info, DiagLoc, EltTy, |
| 2247 | Value.getArrayFiller(), Usage, SubobjectLoc, |
| 2248 | CheckedTemps); |
| 2249 | } |
| 2250 | if (Value.isUnion() && Value.getUnionField()) { |
| 2251 | return CheckEvaluationResult( |
| 2252 | CERK, Info, DiagLoc, Value.getUnionField()->getType(), |
| 2253 | Value.getUnionValue(), Usage, Value.getUnionField()->getLocation(), |
| 2254 | CheckedTemps); |
| 2255 | } |
| 2256 | if (Value.isStruct()) { |
| 2257 | RecordDecl *RD = Type->castAs<RecordType>()->getDecl(); |
| 2258 | if (const CXXRecordDecl *CD = dyn_cast<CXXRecordDecl>(RD)) { |
| 2259 | unsigned BaseIndex = 0; |
| 2260 | for (const CXXBaseSpecifier &BS : CD->bases()) { |
| 2261 | if (!CheckEvaluationResult(CERK, Info, DiagLoc, BS.getType(), |
| 2262 | Value.getStructBase(BaseIndex), Usage, |
| 2263 | BS.getBeginLoc(), CheckedTemps)) |
| 2264 | return false; |
| 2265 | ++BaseIndex; |
| 2266 | } |
| 2267 | } |
| 2268 | for (const auto *I : RD->fields()) { |
| 2269 | if (I->isUnnamedBitfield()) |
| 2270 | continue; |
| 2271 | |
| 2272 | if (!CheckEvaluationResult(CERK, Info, DiagLoc, I->getType(), |
| 2273 | Value.getStructField(I->getFieldIndex()), |
| 2274 | Usage, I->getLocation(), CheckedTemps)) |
| 2275 | return false; |
| 2276 | } |
| 2277 | } |
| 2278 | |
| 2279 | if (Value.isLValue() && |
| 2280 | CERK == CheckEvaluationResultKind::ConstantExpression) { |
| 2281 | LValue LVal; |
| 2282 | LVal.setFrom(Info.Ctx, Value); |
| 2283 | return CheckLValueConstantExpression(Info, DiagLoc, Type, LVal, Usage, |
| 2284 | CheckedTemps); |
| 2285 | } |
| 2286 | |
| 2287 | if (Value.isMemberPointer() && |
| 2288 | CERK == CheckEvaluationResultKind::ConstantExpression) |
| 2289 | return CheckMemberPointerConstantExpression(Info, DiagLoc, Type, Value, Usage); |
| 2290 | |
| 2291 | // Everything else is fine. |
| 2292 | return true; |
| 2293 | } |
| 2294 | |
| 2295 | /// Check that this core constant expression value is a valid value for a |
| 2296 | /// constant expression. If not, report an appropriate diagnostic. Does not |
| 2297 | /// check that the expression is of literal type. |
| 2298 | static bool |
| 2299 | CheckConstantExpression(EvalInfo &Info, SourceLocation DiagLoc, QualType Type, |
| 2300 | const APValue &Value, |
| 2301 | Expr::ConstExprUsage Usage = Expr::EvaluateForCodeGen) { |
| 2302 | // Nothing to check for a constant expression of type 'cv void'. |
| 2303 | if (Type->isVoidType()) |
| 2304 | return true; |
| 2305 | |
| 2306 | CheckedTemporaries CheckedTemps; |
| 2307 | return CheckEvaluationResult(CheckEvaluationResultKind::ConstantExpression, |
| 2308 | Info, DiagLoc, Type, Value, Usage, |
| 2309 | SourceLocation(), CheckedTemps); |
| 2310 | } |
| 2311 | |
| 2312 | /// Check that this evaluated value is fully-initialized and can be loaded by |
| 2313 | /// an lvalue-to-rvalue conversion. |
| 2314 | static bool CheckFullyInitialized(EvalInfo &Info, SourceLocation DiagLoc, |
| 2315 | QualType Type, const APValue &Value) { |
| 2316 | CheckedTemporaries CheckedTemps; |
| 2317 | return CheckEvaluationResult( |
| 2318 | CheckEvaluationResultKind::FullyInitialized, Info, DiagLoc, Type, Value, |
| 2319 | Expr::EvaluateForCodeGen, SourceLocation(), CheckedTemps); |
| 2320 | } |
| 2321 | |
| 2322 | /// Enforce C++2a [expr.const]/4.17, which disallows new-expressions unless |
| 2323 | /// "the allocated storage is deallocated within the evaluation". |
| 2324 | static bool CheckMemoryLeaks(EvalInfo &Info) { |
| 2325 | if (!Info.HeapAllocs.empty()) { |
| 2326 | // We can still fold to a constant despite a compile-time memory leak, |
| 2327 | // so long as the heap allocation isn't referenced in the result (we check |
| 2328 | // that in CheckConstantExpression). |
| 2329 | Info.CCEDiag(Info.HeapAllocs.begin()->second.AllocExpr, |
| 2330 | diag::note_constexpr_memory_leak) |
| 2331 | << unsigned(Info.HeapAllocs.size() - 1); |
| 2332 | } |
| 2333 | return true; |
| 2334 | } |
| 2335 | |
| 2336 | static bool EvalPointerValueAsBool(const APValue &Value, bool &Result) { |
| 2337 | // A null base expression indicates a null pointer. These are always |
| 2338 | // evaluatable, and they are false unless the offset is zero. |
| 2339 | if (!Value.getLValueBase()) { |
| 2340 | Result = !Value.getLValueOffset().isZero(); |
| 2341 | return true; |
| 2342 | } |
| 2343 | |
| 2344 | // We have a non-null base. These are generally known to be true, but if it's |
| 2345 | // a weak declaration it can be null at runtime. |
| 2346 | Result = true; |
| 2347 | const ValueDecl *Decl = Value.getLValueBase().dyn_cast<const ValueDecl*>(); |
| 2348 | return !Decl || !Decl->isWeak(); |
| 2349 | } |
| 2350 | |
| 2351 | static bool HandleConversionToBool(const APValue &Val, bool &Result) { |
| 2352 | switch (Val.getKind()) { |
| 2353 | case APValue::None: |
| 2354 | case APValue::Indeterminate: |
| 2355 | return false; |
| 2356 | case APValue::Int: |
| 2357 | Result = Val.getInt().getBoolValue(); |
| 2358 | return true; |
| 2359 | case APValue::FixedPoint: |
| 2360 | Result = Val.getFixedPoint().getBoolValue(); |
| 2361 | return true; |
| 2362 | case APValue::Float: |
| 2363 | Result = !Val.getFloat().isZero(); |
| 2364 | return true; |
| 2365 | case APValue::ComplexInt: |
| 2366 | Result = Val.getComplexIntReal().getBoolValue() || |
| 2367 | Val.getComplexIntImag().getBoolValue(); |
| 2368 | return true; |
| 2369 | case APValue::ComplexFloat: |
| 2370 | Result = !Val.getComplexFloatReal().isZero() || |
| 2371 | !Val.getComplexFloatImag().isZero(); |
| 2372 | return true; |
| 2373 | case APValue::LValue: |
| 2374 | return EvalPointerValueAsBool(Val, Result); |
| 2375 | case APValue::MemberPointer: |
| 2376 | Result = Val.getMemberPointerDecl(); |
| 2377 | return true; |
| 2378 | case APValue::Vector: |
| 2379 | case APValue::Array: |
| 2380 | case APValue::Struct: |
| 2381 | case APValue::Union: |
| 2382 | case APValue::AddrLabelDiff: |
| 2383 | return false; |
| 2384 | } |
| 2385 | |
| 2386 | llvm_unreachable("unknown APValue kind")::llvm::llvm_unreachable_internal("unknown APValue kind", "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 2386); |
| 2387 | } |
| 2388 | |
| 2389 | static bool EvaluateAsBooleanCondition(const Expr *E, bool &Result, |
| 2390 | EvalInfo &Info) { |
| 2391 | assert(E->isRValue() && "missing lvalue-to-rvalue conv in bool condition")((E->isRValue() && "missing lvalue-to-rvalue conv in bool condition" ) ? static_cast<void> (0) : __assert_fail ("E->isRValue() && \"missing lvalue-to-rvalue conv in bool condition\"" , "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 2391, __PRETTY_FUNCTION__)); |
| 2392 | APValue Val; |
| 2393 | if (!Evaluate(Val, Info, E)) |
| 2394 | return false; |
| 2395 | return HandleConversionToBool(Val, Result); |
| 2396 | } |
| 2397 | |
| 2398 | template<typename T> |
| 2399 | static bool HandleOverflow(EvalInfo &Info, const Expr *E, |
| 2400 | const T &SrcValue, QualType DestType) { |
| 2401 | Info.CCEDiag(E, diag::note_constexpr_overflow) |
| 2402 | << SrcValue << DestType; |
| 2403 | return Info.noteUndefinedBehavior(); |
| 2404 | } |
| 2405 | |
| 2406 | static bool HandleFloatToIntCast(EvalInfo &Info, const Expr *E, |
| 2407 | QualType SrcType, const APFloat &Value, |
| 2408 | QualType DestType, APSInt &Result) { |
| 2409 | unsigned DestWidth = Info.Ctx.getIntWidth(DestType); |
| 2410 | // Determine whether we are converting to unsigned or signed. |
| 2411 | bool DestSigned = DestType->isSignedIntegerOrEnumerationType(); |
| 2412 | |
| 2413 | Result = APSInt(DestWidth, !DestSigned); |
| 2414 | bool ignored; |
| 2415 | if (Value.convertToInteger(Result, llvm::APFloat::rmTowardZero, &ignored) |
| 2416 | & APFloat::opInvalidOp) |
| 2417 | return HandleOverflow(Info, E, Value, DestType); |
| 2418 | return true; |
| 2419 | } |
| 2420 | |
| 2421 | static bool HandleFloatToFloatCast(EvalInfo &Info, const Expr *E, |
| 2422 | QualType SrcType, QualType DestType, |
| 2423 | APFloat &Result) { |
| 2424 | APFloat Value = Result; |
| 2425 | bool ignored; |
| 2426 | Result.convert(Info.Ctx.getFloatTypeSemantics(DestType), |
| 2427 | APFloat::rmNearestTiesToEven, &ignored); |
| 2428 | return true; |
| 2429 | } |
| 2430 | |
| 2431 | static APSInt HandleIntToIntCast(EvalInfo &Info, const Expr *E, |
| 2432 | QualType DestType, QualType SrcType, |
| 2433 | const APSInt &Value) { |
| 2434 | unsigned DestWidth = Info.Ctx.getIntWidth(DestType); |
| 2435 | // Figure out if this is a truncate, extend or noop cast. |
| 2436 | // If the input is signed, do a sign extend, noop, or truncate. |
| 2437 | APSInt Result = Value.extOrTrunc(DestWidth); |
| 2438 | Result.setIsUnsigned(DestType->isUnsignedIntegerOrEnumerationType()); |
| 2439 | if (DestType->isBooleanType()) |
| 2440 | Result = Value.getBoolValue(); |
| 2441 | return Result; |
| 2442 | } |
| 2443 | |
| 2444 | static bool HandleIntToFloatCast(EvalInfo &Info, const Expr *E, |
| 2445 | QualType SrcType, const APSInt &Value, |
| 2446 | QualType DestType, APFloat &Result) { |
| 2447 | Result = APFloat(Info.Ctx.getFloatTypeSemantics(DestType), 1); |
| 2448 | Result.convertFromAPInt(Value, Value.isSigned(), |
| 2449 | APFloat::rmNearestTiesToEven); |
| 2450 | return true; |
| 2451 | } |
| 2452 | |
| 2453 | static bool truncateBitfieldValue(EvalInfo &Info, const Expr *E, |
| 2454 | APValue &Value, const FieldDecl *FD) { |
| 2455 | assert(FD->isBitField() && "truncateBitfieldValue on non-bitfield")((FD->isBitField() && "truncateBitfieldValue on non-bitfield" ) ? static_cast<void> (0) : __assert_fail ("FD->isBitField() && \"truncateBitfieldValue on non-bitfield\"" , "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 2455, __PRETTY_FUNCTION__)); |
| 2456 | |
| 2457 | if (!Value.isInt()) { |
| 2458 | // Trying to store a pointer-cast-to-integer into a bitfield. |
| 2459 | // FIXME: In this case, we should provide the diagnostic for casting |
| 2460 | // a pointer to an integer. |
| 2461 | assert(Value.isLValue() && "integral value neither int nor lvalue?")((Value.isLValue() && "integral value neither int nor lvalue?" ) ? static_cast<void> (0) : __assert_fail ("Value.isLValue() && \"integral value neither int nor lvalue?\"" , "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 2461, __PRETTY_FUNCTION__)); |
| 2462 | Info.FFDiag(E); |
| 2463 | return false; |
| 2464 | } |
| 2465 | |
| 2466 | APSInt &Int = Value.getInt(); |
| 2467 | unsigned OldBitWidth = Int.getBitWidth(); |
| 2468 | unsigned NewBitWidth = FD->getBitWidthValue(Info.Ctx); |
| 2469 | if (NewBitWidth < OldBitWidth) |
| 2470 | Int = Int.trunc(NewBitWidth).extend(OldBitWidth); |
| 2471 | return true; |
| 2472 | } |
| 2473 | |
| 2474 | static bool EvalAndBitcastToAPInt(EvalInfo &Info, const Expr *E, |
| 2475 | llvm::APInt &Res) { |
| 2476 | APValue SVal; |
| 2477 | if (!Evaluate(SVal, Info, E)) |
| 2478 | return false; |
| 2479 | if (SVal.isInt()) { |
| 2480 | Res = SVal.getInt(); |
| 2481 | return true; |
| 2482 | } |
| 2483 | if (SVal.isFloat()) { |
| 2484 | Res = SVal.getFloat().bitcastToAPInt(); |
| 2485 | return true; |
| 2486 | } |
| 2487 | if (SVal.isVector()) { |
| 2488 | QualType VecTy = E->getType(); |
| 2489 | unsigned VecSize = Info.Ctx.getTypeSize(VecTy); |
| 2490 | QualType EltTy = VecTy->castAs<VectorType>()->getElementType(); |
| 2491 | unsigned EltSize = Info.Ctx.getTypeSize(EltTy); |
| 2492 | bool BigEndian = Info.Ctx.getTargetInfo().isBigEndian(); |
| 2493 | Res = llvm::APInt::getNullValue(VecSize); |
| 2494 | for (unsigned i = 0; i < SVal.getVectorLength(); i++) { |
| 2495 | APValue &Elt = SVal.getVectorElt(i); |
| 2496 | llvm::APInt EltAsInt; |
| 2497 | if (Elt.isInt()) { |
| 2498 | EltAsInt = Elt.getInt(); |
| 2499 | } else if (Elt.isFloat()) { |
| 2500 | EltAsInt = Elt.getFloat().bitcastToAPInt(); |
| 2501 | } else { |
| 2502 | // Don't try to handle vectors of anything other than int or float |
| 2503 | // (not sure if it's possible to hit this case). |
| 2504 | Info.FFDiag(E, diag::note_invalid_subexpr_in_const_expr); |
| 2505 | return false; |
| 2506 | } |
| 2507 | unsigned BaseEltSize = EltAsInt.getBitWidth(); |
| 2508 | if (BigEndian) |
| 2509 | Res |= EltAsInt.zextOrTrunc(VecSize).rotr(i*EltSize+BaseEltSize); |
| 2510 | else |
| 2511 | Res |= EltAsInt.zextOrTrunc(VecSize).rotl(i*EltSize); |
| 2512 | } |
| 2513 | return true; |
| 2514 | } |
| 2515 | // Give up if the input isn't an int, float, or vector. For example, we |
| 2516 | // reject "(v4i16)(intptr_t)&a". |
| 2517 | Info.FFDiag(E, diag::note_invalid_subexpr_in_const_expr); |
| 2518 | return false; |
| 2519 | } |
| 2520 | |
| 2521 | /// Perform the given integer operation, which is known to need at most BitWidth |
| 2522 | /// bits, and check for overflow in the original type (if that type was not an |
| 2523 | /// unsigned type). |
| 2524 | template<typename Operation> |
| 2525 | static bool CheckedIntArithmetic(EvalInfo &Info, const Expr *E, |
| 2526 | const APSInt &LHS, const APSInt &RHS, |
| 2527 | unsigned BitWidth, Operation Op, |
| 2528 | APSInt &Result) { |
| 2529 | if (LHS.isUnsigned()) { |
| 2530 | Result = Op(LHS, RHS); |
| 2531 | return true; |
| 2532 | } |
| 2533 | |
| 2534 | APSInt Value(Op(LHS.extend(BitWidth), RHS.extend(BitWidth)), false); |
| 2535 | Result = Value.trunc(LHS.getBitWidth()); |
| 2536 | if (Result.extend(BitWidth) != Value) { |
| 2537 | if (Info.checkingForUndefinedBehavior()) |
| 2538 | Info.Ctx.getDiagnostics().Report(E->getExprLoc(), |
| 2539 | diag::warn_integer_constant_overflow) |
| 2540 | << Result.toString(10) << E->getType(); |
| 2541 | else |
| 2542 | return HandleOverflow(Info, E, Value, E->getType()); |
| 2543 | } |
| 2544 | return true; |
| 2545 | } |
| 2546 | |
| 2547 | /// Perform the given binary integer operation. |
| 2548 | static bool handleIntIntBinOp(EvalInfo &Info, const Expr *E, const APSInt &LHS, |
| 2549 | BinaryOperatorKind Opcode, APSInt RHS, |
| 2550 | APSInt &Result) { |
| 2551 | switch (Opcode) { |
| 2552 | default: |
| 2553 | Info.FFDiag(E); |
| 2554 | return false; |
| 2555 | case BO_Mul: |
| 2556 | return CheckedIntArithmetic(Info, E, LHS, RHS, LHS.getBitWidth() * 2, |
| 2557 | std::multiplies<APSInt>(), Result); |
| 2558 | case BO_Add: |
| 2559 | return CheckedIntArithmetic(Info, E, LHS, RHS, LHS.getBitWidth() + 1, |
| 2560 | std::plus<APSInt>(), Result); |
| 2561 | case BO_Sub: |
| 2562 | return CheckedIntArithmetic(Info, E, LHS, RHS, LHS.getBitWidth() + 1, |
| 2563 | std::minus<APSInt>(), Result); |
| 2564 | case BO_And: Result = LHS & RHS; return true; |
| 2565 | case BO_Xor: Result = LHS ^ RHS; return true; |
| 2566 | case BO_Or: Result = LHS | RHS; return true; |
| 2567 | case BO_Div: |
| 2568 | case BO_Rem: |
| 2569 | if (RHS == 0) { |
| 2570 | Info.FFDiag(E, diag::note_expr_divide_by_zero); |
| 2571 | return false; |
| 2572 | } |
| 2573 | Result = (Opcode == BO_Rem ? LHS % RHS : LHS / RHS); |
| 2574 | // Check for overflow case: INT_MIN / -1 or INT_MIN % -1. APSInt supports |
| 2575 | // this operation and gives the two's complement result. |
| 2576 | if (RHS.isNegative() && RHS.isAllOnesValue() && |
| 2577 | LHS.isSigned() && LHS.isMinSignedValue()) |
| 2578 | return HandleOverflow(Info, E, -LHS.extend(LHS.getBitWidth() + 1), |
| 2579 | E->getType()); |
| 2580 | return true; |
| 2581 | case BO_Shl: { |
| 2582 | if (Info.getLangOpts().OpenCL) |
| 2583 | // OpenCL 6.3j: shift values are effectively % word size of LHS. |
| 2584 | RHS &= APSInt(llvm::APInt(RHS.getBitWidth(), |
| 2585 | static_cast<uint64_t>(LHS.getBitWidth() - 1)), |
| 2586 | RHS.isUnsigned()); |
| 2587 | else if (RHS.isSigned() && RHS.isNegative()) { |
| 2588 | // During constant-folding, a negative shift is an opposite shift. Such |
| 2589 | // a shift is not a constant expression. |
| 2590 | Info.CCEDiag(E, diag::note_constexpr_negative_shift) << RHS; |
| 2591 | RHS = -RHS; |
| 2592 | goto shift_right; |
| 2593 | } |
| 2594 | shift_left: |
| 2595 | // C++11 [expr.shift]p1: Shift width must be less than the bit width of |
| 2596 | // the shifted type. |
| 2597 | unsigned SA = (unsigned) RHS.getLimitedValue(LHS.getBitWidth()-1); |
| 2598 | if (SA != RHS) { |
| 2599 | Info.CCEDiag(E, diag::note_constexpr_large_shift) |
| 2600 | << RHS << E->getType() << LHS.getBitWidth(); |
| 2601 | } else if (LHS.isSigned() && !Info.getLangOpts().CPlusPlus20) { |
| 2602 | // C++11 [expr.shift]p2: A signed left shift must have a non-negative |
| 2603 | // operand, and must not overflow the corresponding unsigned type. |
| 2604 | // C++2a [expr.shift]p2: E1 << E2 is the unique value congruent to |
| 2605 | // E1 x 2^E2 module 2^N. |
| 2606 | if (LHS.isNegative()) |
| 2607 | Info.CCEDiag(E, diag::note_constexpr_lshift_of_negative) << LHS; |
| 2608 | else if (LHS.countLeadingZeros() < SA) |
| 2609 | Info.CCEDiag(E, diag::note_constexpr_lshift_discards); |
| 2610 | } |
| 2611 | Result = LHS << SA; |
| 2612 | return true; |
| 2613 | } |
| 2614 | case BO_Shr: { |
| 2615 | if (Info.getLangOpts().OpenCL) |
| 2616 | // OpenCL 6.3j: shift values are effectively % word size of LHS. |
| 2617 | RHS &= APSInt(llvm::APInt(RHS.getBitWidth(), |
| 2618 | static_cast<uint64_t>(LHS.getBitWidth() - 1)), |
| 2619 | RHS.isUnsigned()); |
| 2620 | else if (RHS.isSigned() && RHS.isNegative()) { |
| 2621 | // During constant-folding, a negative shift is an opposite shift. Such a |
| 2622 | // shift is not a constant expression. |
| 2623 | Info.CCEDiag(E, diag::note_constexpr_negative_shift) << RHS; |
| 2624 | RHS = -RHS; |
| 2625 | goto shift_left; |
| 2626 | } |
| 2627 | shift_right: |
| 2628 | // C++11 [expr.shift]p1: Shift width must be less than the bit width of the |
| 2629 | // shifted type. |
| 2630 | unsigned SA = (unsigned) RHS.getLimitedValue(LHS.getBitWidth()-1); |
| 2631 | if (SA != RHS) |
| 2632 | Info.CCEDiag(E, diag::note_constexpr_large_shift) |
| 2633 | << RHS << E->getType() << LHS.getBitWidth(); |
| 2634 | Result = LHS >> SA; |
| 2635 | return true; |
| 2636 | } |
| 2637 | |
| 2638 | case BO_LT: Result = LHS < RHS; return true; |
| 2639 | case BO_GT: Result = LHS > RHS; return true; |
| 2640 | case BO_LE: Result = LHS <= RHS; return true; |
| 2641 | case BO_GE: Result = LHS >= RHS; return true; |
| 2642 | case BO_EQ: Result = LHS == RHS; return true; |
| 2643 | case BO_NE: Result = LHS != RHS; return true; |
| 2644 | case BO_Cmp: |
| 2645 | llvm_unreachable("BO_Cmp should be handled elsewhere")::llvm::llvm_unreachable_internal("BO_Cmp should be handled elsewhere" , "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 2645); |
| 2646 | } |
| 2647 | } |
| 2648 | |
| 2649 | /// Perform the given binary floating-point operation, in-place, on LHS. |
| 2650 | static bool handleFloatFloatBinOp(EvalInfo &Info, const Expr *E, |
| 2651 | APFloat &LHS, BinaryOperatorKind Opcode, |
| 2652 | const APFloat &RHS) { |
| 2653 | switch (Opcode) { |
| 2654 | default: |
| 2655 | Info.FFDiag(E); |
| 2656 | return false; |
| 2657 | case BO_Mul: |
| 2658 | LHS.multiply(RHS, APFloat::rmNearestTiesToEven); |
| 2659 | break; |
| 2660 | case BO_Add: |
| 2661 | LHS.add(RHS, APFloat::rmNearestTiesToEven); |
| 2662 | break; |
| 2663 | case BO_Sub: |
| 2664 | LHS.subtract(RHS, APFloat::rmNearestTiesToEven); |
| 2665 | break; |
| 2666 | case BO_Div: |
| 2667 | // [expr.mul]p4: |
| 2668 | // If the second operand of / or % is zero the behavior is undefined. |
| 2669 | if (RHS.isZero()) |
| 2670 | Info.CCEDiag(E, diag::note_expr_divide_by_zero); |
| 2671 | LHS.divide(RHS, APFloat::rmNearestTiesToEven); |
| 2672 | break; |
| 2673 | } |
| 2674 | |
| 2675 | // [expr.pre]p4: |
| 2676 | // If during the evaluation of an expression, the result is not |
| 2677 | // mathematically defined [...], the behavior is undefined. |
| 2678 | // FIXME: C++ rules require us to not conform to IEEE 754 here. |
| 2679 | if (LHS.isNaN()) { |
| 2680 | Info.CCEDiag(E, diag::note_constexpr_float_arithmetic) << LHS.isNaN(); |
| 2681 | return Info.noteUndefinedBehavior(); |
| 2682 | } |
| 2683 | return true; |
| 2684 | } |
| 2685 | |
| 2686 | static bool handleLogicalOpForVector(const APInt &LHSValue, |
| 2687 | BinaryOperatorKind Opcode, |
| 2688 | const APInt &RHSValue, APInt &Result) { |
| 2689 | bool LHS = (LHSValue != 0); |
| 2690 | bool RHS = (RHSValue != 0); |
| 2691 | |
| 2692 | if (Opcode == BO_LAnd) |
| 2693 | Result = LHS && RHS; |
| 2694 | else |
| 2695 | Result = LHS || RHS; |
| 2696 | return true; |
| 2697 | } |
| 2698 | static bool handleLogicalOpForVector(const APFloat &LHSValue, |
| 2699 | BinaryOperatorKind Opcode, |
| 2700 | const APFloat &RHSValue, APInt &Result) { |
| 2701 | bool LHS = !LHSValue.isZero(); |
| 2702 | bool RHS = !RHSValue.isZero(); |
| 2703 | |
| 2704 | if (Opcode == BO_LAnd) |
| 2705 | Result = LHS && RHS; |
| 2706 | else |
| 2707 | Result = LHS || RHS; |
| 2708 | return true; |
| 2709 | } |
| 2710 | |
| 2711 | static bool handleLogicalOpForVector(const APValue &LHSValue, |
| 2712 | BinaryOperatorKind Opcode, |
| 2713 | const APValue &RHSValue, APInt &Result) { |
| 2714 | // The result is always an int type, however operands match the first. |
| 2715 | if (LHSValue.getKind() == APValue::Int) |
| 2716 | return handleLogicalOpForVector(LHSValue.getInt(), Opcode, |
| 2717 | RHSValue.getInt(), Result); |
| 2718 | assert(LHSValue.getKind() == APValue::Float && "Should be no other options")((LHSValue.getKind() == APValue::Float && "Should be no other options" ) ? static_cast<void> (0) : __assert_fail ("LHSValue.getKind() == APValue::Float && \"Should be no other options\"" , "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 2718, __PRETTY_FUNCTION__)); |
| 2719 | return handleLogicalOpForVector(LHSValue.getFloat(), Opcode, |
| 2720 | RHSValue.getFloat(), Result); |
| 2721 | } |
| 2722 | |
| 2723 | template <typename APTy> |
| 2724 | static bool |
| 2725 | handleCompareOpForVectorHelper(const APTy &LHSValue, BinaryOperatorKind Opcode, |
| 2726 | const APTy &RHSValue, APInt &Result) { |
| 2727 | switch (Opcode) { |
| 2728 | default: |
| 2729 | llvm_unreachable("unsupported binary operator")::llvm::llvm_unreachable_internal("unsupported binary operator" , "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 2729); |
| 2730 | case BO_EQ: |
| 2731 | Result = (LHSValue == RHSValue); |
| 2732 | break; |
| 2733 | case BO_NE: |
| 2734 | Result = (LHSValue != RHSValue); |
| 2735 | break; |
| 2736 | case BO_LT: |
| 2737 | Result = (LHSValue < RHSValue); |
| 2738 | break; |
| 2739 | case BO_GT: |
| 2740 | Result = (LHSValue > RHSValue); |
| 2741 | break; |
| 2742 | case BO_LE: |
| 2743 | Result = (LHSValue <= RHSValue); |
| 2744 | break; |
| 2745 | case BO_GE: |
| 2746 | Result = (LHSValue >= RHSValue); |
| 2747 | break; |
| 2748 | } |
| 2749 | |
| 2750 | return true; |
| 2751 | } |
| 2752 | |
| 2753 | static bool handleCompareOpForVector(const APValue &LHSValue, |
| 2754 | BinaryOperatorKind Opcode, |
| 2755 | const APValue &RHSValue, APInt &Result) { |
| 2756 | // The result is always an int type, however operands match the first. |
| 2757 | if (LHSValue.getKind() == APValue::Int) |
| 2758 | return handleCompareOpForVectorHelper(LHSValue.getInt(), Opcode, |
| 2759 | RHSValue.getInt(), Result); |
| 2760 | assert(LHSValue.getKind() == APValue::Float && "Should be no other options")((LHSValue.getKind() == APValue::Float && "Should be no other options" ) ? static_cast<void> (0) : __assert_fail ("LHSValue.getKind() == APValue::Float && \"Should be no other options\"" , "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 2760, __PRETTY_FUNCTION__)); |
| 2761 | return handleCompareOpForVectorHelper(LHSValue.getFloat(), Opcode, |
| 2762 | RHSValue.getFloat(), Result); |
| 2763 | } |
| 2764 | |
| 2765 | // Perform binary operations for vector types, in place on the LHS. |
| 2766 | static bool handleVectorVectorBinOp(EvalInfo &Info, const Expr *E, |
| 2767 | BinaryOperatorKind Opcode, |
| 2768 | APValue &LHSValue, |
| 2769 | const APValue &RHSValue) { |
| 2770 | assert(Opcode != BO_PtrMemD && Opcode != BO_PtrMemI &&((Opcode != BO_PtrMemD && Opcode != BO_PtrMemI && "Operation not supported on vector types") ? static_cast< void> (0) : __assert_fail ("Opcode != BO_PtrMemD && Opcode != BO_PtrMemI && \"Operation not supported on vector types\"" , "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 2771, __PRETTY_FUNCTION__)) |
| 2771 | "Operation not supported on vector types")((Opcode != BO_PtrMemD && Opcode != BO_PtrMemI && "Operation not supported on vector types") ? static_cast< void> (0) : __assert_fail ("Opcode != BO_PtrMemD && Opcode != BO_PtrMemI && \"Operation not supported on vector types\"" , "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 2771, __PRETTY_FUNCTION__)); |
| 2772 | |
| 2773 | const auto *VT = E->getType()->castAs<VectorType>(); |
| 2774 | unsigned NumElements = VT->getNumElements(); |
| 2775 | QualType EltTy = VT->getElementType(); |
| 2776 | |
| 2777 | // In the cases (typically C as I've observed) where we aren't evaluating |
| 2778 | // constexpr but are checking for cases where the LHS isn't yet evaluatable, |
| 2779 | // just give up. |
| 2780 | if (!LHSValue.isVector()) { |
| 2781 | assert(LHSValue.isLValue() &&((LHSValue.isLValue() && "A vector result that isn't a vector OR uncalculated LValue" ) ? static_cast<void> (0) : __assert_fail ("LHSValue.isLValue() && \"A vector result that isn't a vector OR uncalculated LValue\"" , "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 2782, __PRETTY_FUNCTION__)) |
| 2782 | "A vector result that isn't a vector OR uncalculated LValue")((LHSValue.isLValue() && "A vector result that isn't a vector OR uncalculated LValue" ) ? static_cast<void> (0) : __assert_fail ("LHSValue.isLValue() && \"A vector result that isn't a vector OR uncalculated LValue\"" , "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 2782, __PRETTY_FUNCTION__)); |
| 2783 | Info.FFDiag(E); |
| 2784 | return false; |
| 2785 | } |
| 2786 | |
| 2787 | assert(LHSValue.getVectorLength() == NumElements &&((LHSValue.getVectorLength() == NumElements && RHSValue .getVectorLength() == NumElements && "Different vector sizes" ) ? static_cast<void> (0) : __assert_fail ("LHSValue.getVectorLength() == NumElements && RHSValue.getVectorLength() == NumElements && \"Different vector sizes\"" , "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 2788, __PRETTY_FUNCTION__)) |
| 2788 | RHSValue.getVectorLength() == NumElements && "Different vector sizes")((LHSValue.getVectorLength() == NumElements && RHSValue .getVectorLength() == NumElements && "Different vector sizes" ) ? static_cast<void> (0) : __assert_fail ("LHSValue.getVectorLength() == NumElements && RHSValue.getVectorLength() == NumElements && \"Different vector sizes\"" , "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 2788, __PRETTY_FUNCTION__)); |
| 2789 | |
| 2790 | SmallVector<APValue, 4> ResultElements; |
| 2791 | |
| 2792 | for (unsigned EltNum = 0; EltNum < NumElements; ++EltNum) { |
| 2793 | APValue LHSElt = LHSValue.getVectorElt(EltNum); |
| 2794 | APValue RHSElt = RHSValue.getVectorElt(EltNum); |
| 2795 | |
| 2796 | if (EltTy->isIntegerType()) { |
| 2797 | APSInt EltResult{Info.Ctx.getIntWidth(EltTy), |
| 2798 | EltTy->isUnsignedIntegerType()}; |
| 2799 | bool Success = true; |
| 2800 | |
| 2801 | if (BinaryOperator::isLogicalOp(Opcode)) |
| 2802 | Success = handleLogicalOpForVector(LHSElt, Opcode, RHSElt, EltResult); |
| 2803 | else if (BinaryOperator::isComparisonOp(Opcode)) |
| 2804 | Success = handleCompareOpForVector(LHSElt, Opcode, RHSElt, EltResult); |
| 2805 | else |
| 2806 | Success = handleIntIntBinOp(Info, E, LHSElt.getInt(), Opcode, |
| 2807 | RHSElt.getInt(), EltResult); |
| 2808 | |
| 2809 | if (!Success) { |
| 2810 | Info.FFDiag(E); |
| 2811 | return false; |
| 2812 | } |
| 2813 | ResultElements.emplace_back(EltResult); |
| 2814 | |
| 2815 | } else if (EltTy->isFloatingType()) { |
| 2816 | assert(LHSElt.getKind() == APValue::Float &&((LHSElt.getKind() == APValue::Float && RHSElt.getKind () == APValue::Float && "Mismatched LHS/RHS/Result Type" ) ? static_cast<void> (0) : __assert_fail ("LHSElt.getKind() == APValue::Float && RHSElt.getKind() == APValue::Float && \"Mismatched LHS/RHS/Result Type\"" , "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 2818, __PRETTY_FUNCTION__)) |
| 2817 | RHSElt.getKind() == APValue::Float &&((LHSElt.getKind() == APValue::Float && RHSElt.getKind () == APValue::Float && "Mismatched LHS/RHS/Result Type" ) ? static_cast<void> (0) : __assert_fail ("LHSElt.getKind() == APValue::Float && RHSElt.getKind() == APValue::Float && \"Mismatched LHS/RHS/Result Type\"" , "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 2818, __PRETTY_FUNCTION__)) |
| 2818 | "Mismatched LHS/RHS/Result Type")((LHSElt.getKind() == APValue::Float && RHSElt.getKind () == APValue::Float && "Mismatched LHS/RHS/Result Type" ) ? static_cast<void> (0) : __assert_fail ("LHSElt.getKind() == APValue::Float && RHSElt.getKind() == APValue::Float && \"Mismatched LHS/RHS/Result Type\"" , "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 2818, __PRETTY_FUNCTION__)); |
| 2819 | APFloat LHSFloat = LHSElt.getFloat(); |
| 2820 | |
| 2821 | if (!handleFloatFloatBinOp(Info, E, LHSFloat, Opcode, |
| 2822 | RHSElt.getFloat())) { |
| 2823 | Info.FFDiag(E); |
| 2824 | return false; |
| 2825 | } |
| 2826 | |
| 2827 | ResultElements.emplace_back(LHSFloat); |
| 2828 | } |
| 2829 | } |
| 2830 | |
| 2831 | LHSValue = APValue(ResultElements.data(), ResultElements.size()); |
| 2832 | return true; |
| 2833 | } |
| 2834 | |
| 2835 | /// Cast an lvalue referring to a base subobject to a derived class, by |
| 2836 | /// truncating the lvalue's path to the given length. |
| 2837 | static bool CastToDerivedClass(EvalInfo &Info, const Expr *E, LValue &Result, |
| 2838 | const RecordDecl *TruncatedType, |
| 2839 | unsigned TruncatedElements) { |
| 2840 | SubobjectDesignator &D = Result.Designator; |
| 2841 | |
| 2842 | // Check we actually point to a derived class object. |
| 2843 | if (TruncatedElements == D.Entries.size()) |
| 2844 | return true; |
| 2845 | assert(TruncatedElements >= D.MostDerivedPathLength &&((TruncatedElements >= D.MostDerivedPathLength && "not casting to a derived class" ) ? static_cast<void> (0) : __assert_fail ("TruncatedElements >= D.MostDerivedPathLength && \"not casting to a derived class\"" , "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 2846, __PRETTY_FUNCTION__)) |
| 2846 | "not casting to a derived class")((TruncatedElements >= D.MostDerivedPathLength && "not casting to a derived class" ) ? static_cast<void> (0) : __assert_fail ("TruncatedElements >= D.MostDerivedPathLength && \"not casting to a derived class\"" , "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 2846, __PRETTY_FUNCTION__)); |
| 2847 | if (!Result.checkSubobject(Info, E, CSK_Derived)) |
| 2848 | return false; |
| 2849 | |
| 2850 | // Truncate the path to the subobject, and remove any derived-to-base offsets. |
| 2851 | const RecordDecl *RD = TruncatedType; |
| 2852 | for (unsigned I = TruncatedElements, N = D.Entries.size(); I != N; ++I) { |
| 2853 | if (RD->isInvalidDecl()) return false; |
| 2854 | const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(RD); |
| 2855 | const CXXRecordDecl *Base = getAsBaseClass(D.Entries[I]); |
| 2856 | if (isVirtualBaseClass(D.Entries[I])) |
| 2857 | Result.Offset -= Layout.getVBaseClassOffset(Base); |
| 2858 | else |
| 2859 | Result.Offset -= Layout.getBaseClassOffset(Base); |
| 2860 | RD = Base; |
| 2861 | } |
| 2862 | D.Entries.resize(TruncatedElements); |
| 2863 | return true; |
| 2864 | } |
| 2865 | |
| 2866 | static bool HandleLValueDirectBase(EvalInfo &Info, const Expr *E, LValue &Obj, |
| 2867 | const CXXRecordDecl *Derived, |
| 2868 | const CXXRecordDecl *Base, |
| 2869 | const ASTRecordLayout *RL = nullptr) { |
| 2870 | if (!RL) { |
| 2871 | if (Derived->isInvalidDecl()) return false; |
| 2872 | RL = &Info.Ctx.getASTRecordLayout(Derived); |
| 2873 | } |
| 2874 | |
| 2875 | Obj.getLValueOffset() += RL->getBaseClassOffset(Base); |
| 2876 | Obj.addDecl(Info, E, Base, /*Virtual*/ false); |
| 2877 | return true; |
| 2878 | } |
| 2879 | |
| 2880 | static bool HandleLValueBase(EvalInfo &Info, const Expr *E, LValue &Obj, |
| 2881 | const CXXRecordDecl *DerivedDecl, |
| 2882 | const CXXBaseSpecifier *Base) { |
| 2883 | const CXXRecordDecl *BaseDecl = Base->getType()->getAsCXXRecordDecl(); |
| 2884 | |
| 2885 | if (!Base->isVirtual()) |
| 2886 | return HandleLValueDirectBase(Info, E, Obj, DerivedDecl, BaseDecl); |
| 2887 | |
| 2888 | SubobjectDesignator &D = Obj.Designator; |
| 2889 | if (D.Invalid) |
| 2890 | return false; |
| 2891 | |
| 2892 | // Extract most-derived object and corresponding type. |
| 2893 | DerivedDecl = D.MostDerivedType->getAsCXXRecordDecl(); |
| 2894 | if (!CastToDerivedClass(Info, E, Obj, DerivedDecl, D.MostDerivedPathLength)) |
| 2895 | return false; |
| 2896 | |
| 2897 | // Find the virtual base class. |
| 2898 | if (DerivedDecl->isInvalidDecl()) return false; |
| 2899 | const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(DerivedDecl); |
| 2900 | Obj.getLValueOffset() += Layout.getVBaseClassOffset(BaseDecl); |
| 2901 | Obj.addDecl(Info, E, BaseDecl, /*Virtual*/ true); |
| 2902 | return true; |
| 2903 | } |
| 2904 | |
| 2905 | static bool HandleLValueBasePath(EvalInfo &Info, const CastExpr *E, |
| 2906 | QualType Type, LValue &Result) { |
| 2907 | for (CastExpr::path_const_iterator PathI = E->path_begin(), |
| 2908 | PathE = E->path_end(); |
| 2909 | PathI != PathE; ++PathI) { |
| 2910 | if (!HandleLValueBase(Info, E, Result, Type->getAsCXXRecordDecl(), |
| 2911 | *PathI)) |
| 2912 | return false; |
| 2913 | Type = (*PathI)->getType(); |
| 2914 | } |
| 2915 | return true; |
| 2916 | } |
| 2917 | |
| 2918 | /// Cast an lvalue referring to a derived class to a known base subobject. |
| 2919 | static bool CastToBaseClass(EvalInfo &Info, const Expr *E, LValue &Result, |
| 2920 | const CXXRecordDecl *DerivedRD, |
| 2921 | const CXXRecordDecl *BaseRD) { |
| 2922 | CXXBasePaths Paths(/*FindAmbiguities=*/false, |
| 2923 | /*RecordPaths=*/true, /*DetectVirtual=*/false); |
| 2924 | if (!DerivedRD->isDerivedFrom(BaseRD, Paths)) |
| 2925 | llvm_unreachable("Class must be derived from the passed in base class!")::llvm::llvm_unreachable_internal("Class must be derived from the passed in base class!" , "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 2925); |
| 2926 | |
| 2927 | for (CXXBasePathElement &Elem : Paths.front()) |
| 2928 | if (!HandleLValueBase(Info, E, Result, Elem.Class, Elem.Base)) |
| 2929 | return false; |
| 2930 | return true; |
| 2931 | } |
| 2932 | |
| 2933 | /// Update LVal to refer to the given field, which must be a member of the type |
| 2934 | /// currently described by LVal. |
| 2935 | static bool HandleLValueMember(EvalInfo &Info, const Expr *E, LValue &LVal, |
| 2936 | const FieldDecl *FD, |
| 2937 | const ASTRecordLayout *RL = nullptr) { |
| 2938 | if (!RL) { |
| 2939 | if (FD->getParent()->isInvalidDecl()) return false; |
| 2940 | RL = &Info.Ctx.getASTRecordLayout(FD->getParent()); |
| 2941 | } |
| 2942 | |
| 2943 | unsigned I = FD->getFieldIndex(); |
| 2944 | LVal.adjustOffset(Info.Ctx.toCharUnitsFromBits(RL->getFieldOffset(I))); |
| 2945 | LVal.addDecl(Info, E, FD); |
| 2946 | return true; |
| 2947 | } |
| 2948 | |
| 2949 | /// Update LVal to refer to the given indirect field. |
| 2950 | static bool HandleLValueIndirectMember(EvalInfo &Info, const Expr *E, |
| 2951 | LValue &LVal, |
| 2952 | const IndirectFieldDecl *IFD) { |
| 2953 | for (const auto *C : IFD->chain()) |
| 2954 | if (!HandleLValueMember(Info, E, LVal, cast<FieldDecl>(C))) |
| 2955 | return false; |
| 2956 | return true; |
| 2957 | } |
| 2958 | |
| 2959 | /// Get the size of the given type in char units. |
| 2960 | static bool HandleSizeof(EvalInfo &Info, SourceLocation Loc, |
| 2961 | QualType Type, CharUnits &Size) { |
| 2962 | // sizeof(void), __alignof__(void), sizeof(function) = 1 as a gcc |
| 2963 | // extension. |
| 2964 | if (Type->isVoidType() || Type->isFunctionType()) { |
| 2965 | Size = CharUnits::One(); |
| 2966 | return true; |
| 2967 | } |
| 2968 | |
| 2969 | if (Type->isDependentType()) { |
| 2970 | Info.FFDiag(Loc); |
| 2971 | return false; |
| 2972 | } |
| 2973 | |
| 2974 | if (!Type->isConstantSizeType()) { |
| 2975 | // sizeof(vla) is not a constantexpr: C99 6.5.3.4p2. |
| 2976 | // FIXME: Better diagnostic. |
| 2977 | Info.FFDiag(Loc); |
| 2978 | return false; |
| 2979 | } |
| 2980 | |
| 2981 | Size = Info.Ctx.getTypeSizeInChars(Type); |
| 2982 | return true; |
| 2983 | } |
| 2984 | |
| 2985 | /// Update a pointer value to model pointer arithmetic. |
| 2986 | /// \param Info - Information about the ongoing evaluation. |
| 2987 | /// \param E - The expression being evaluated, for diagnostic purposes. |
| 2988 | /// \param LVal - The pointer value to be updated. |
| 2989 | /// \param EltTy - The pointee type represented by LVal. |
| 2990 | /// \param Adjustment - The adjustment, in objects of type EltTy, to add. |
| 2991 | static bool HandleLValueArrayAdjustment(EvalInfo &Info, const Expr *E, |
| 2992 | LValue &LVal, QualType EltTy, |
| 2993 | APSInt Adjustment) { |
| 2994 | CharUnits SizeOfPointee; |
| 2995 | if (!HandleSizeof(Info, E->getExprLoc(), EltTy, SizeOfPointee)) |
| 2996 | return false; |
| 2997 | |
| 2998 | LVal.adjustOffsetAndIndex(Info, E, Adjustment, SizeOfPointee); |
| 2999 | return true; |
| 3000 | } |
| 3001 | |
| 3002 | static bool HandleLValueArrayAdjustment(EvalInfo &Info, const Expr *E, |
| 3003 | LValue &LVal, QualType EltTy, |
| 3004 | int64_t Adjustment) { |
| 3005 | return HandleLValueArrayAdjustment(Info, E, LVal, EltTy, |
| 3006 | APSInt::get(Adjustment)); |
| 3007 | } |
| 3008 | |
| 3009 | /// Update an lvalue to refer to a component of a complex number. |
| 3010 | /// \param Info - Information about the ongoing evaluation. |
| 3011 | /// \param LVal - The lvalue to be updated. |
| 3012 | /// \param EltTy - The complex number's component type. |
| 3013 | /// \param Imag - False for the real component, true for the imaginary. |
| 3014 | static bool HandleLValueComplexElement(EvalInfo &Info, const Expr *E, |
| 3015 | LValue &LVal, QualType EltTy, |
| 3016 | bool Imag) { |
| 3017 | if (Imag) { |
| 3018 | CharUnits SizeOfComponent; |
| 3019 | if (!HandleSizeof(Info, E->getExprLoc(), EltTy, SizeOfComponent)) |
| 3020 | return false; |
| 3021 | LVal.Offset += SizeOfComponent; |
| 3022 | } |
| 3023 | LVal.addComplex(Info, E, EltTy, Imag); |
| 3024 | return true; |
| 3025 | } |
| 3026 | |
| 3027 | /// Try to evaluate the initializer for a variable declaration. |
| 3028 | /// |
| 3029 | /// \param Info Information about the ongoing evaluation. |
| 3030 | /// \param E An expression to be used when printing diagnostics. |
| 3031 | /// \param VD The variable whose initializer should be obtained. |
| 3032 | /// \param Frame The frame in which the variable was created. Must be null |
| 3033 | /// if this variable is not local to the evaluation. |
| 3034 | /// \param Result Filled in with a pointer to the value of the variable. |
| 3035 | static bool evaluateVarDeclInit(EvalInfo &Info, const Expr *E, |
| 3036 | const VarDecl *VD, CallStackFrame *Frame, |
| 3037 | APValue *&Result, const LValue *LVal) { |
| 3038 | |
| 3039 | // If this is a parameter to an active constexpr function call, perform |
| 3040 | // argument substitution. |
| 3041 | if (const ParmVarDecl *PVD = dyn_cast<ParmVarDecl>(VD)) { |
| 3042 | // Assume arguments of a potential constant expression are unknown |
| 3043 | // constant expressions. |
| 3044 | if (Info.checkingPotentialConstantExpression()) |
| 3045 | return false; |
| 3046 | if (!Frame || !Frame->Arguments) { |
| 3047 | Info.FFDiag(E, diag::note_constexpr_function_param_value_unknown) << VD; |
| 3048 | return false; |
| 3049 | } |
| 3050 | Result = &Frame->Arguments[PVD->getFunctionScopeIndex()]; |
| 3051 | return true; |
| 3052 | } |
| 3053 | |
| 3054 | // If this is a local variable, dig out its value. |
| 3055 | if (Frame) { |
| 3056 | Result = LVal ? Frame->getTemporary(VD, LVal->getLValueVersion()) |
| 3057 | : Frame->getCurrentTemporary(VD); |
| 3058 | if (!Result) { |
| 3059 | // Assume variables referenced within a lambda's call operator that were |
| 3060 | // not declared within the call operator are captures and during checking |
| 3061 | // of a potential constant expression, assume they are unknown constant |
| 3062 | // expressions. |
| 3063 | assert(isLambdaCallOperator(Frame->Callee) &&((isLambdaCallOperator(Frame->Callee) && (VD->getDeclContext () != Frame->Callee || VD->isInitCapture()) && "missing value for local variable" ) ? static_cast<void> (0) : __assert_fail ("isLambdaCallOperator(Frame->Callee) && (VD->getDeclContext() != Frame->Callee || VD->isInitCapture()) && \"missing value for local variable\"" , "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 3065, __PRETTY_FUNCTION__)) |
| 3064 | (VD->getDeclContext() != Frame->Callee || VD->isInitCapture()) &&((isLambdaCallOperator(Frame->Callee) && (VD->getDeclContext () != Frame->Callee || VD->isInitCapture()) && "missing value for local variable" ) ? static_cast<void> (0) : __assert_fail ("isLambdaCallOperator(Frame->Callee) && (VD->getDeclContext() != Frame->Callee || VD->isInitCapture()) && \"missing value for local variable\"" , "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 3065, __PRETTY_FUNCTION__)) |
| 3065 | "missing value for local variable")((isLambdaCallOperator(Frame->Callee) && (VD->getDeclContext () != Frame->Callee || VD->isInitCapture()) && "missing value for local variable" ) ? static_cast<void> (0) : __assert_fail ("isLambdaCallOperator(Frame->Callee) && (VD->getDeclContext() != Frame->Callee || VD->isInitCapture()) && \"missing value for local variable\"" , "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 3065, __PRETTY_FUNCTION__)); |
| 3066 | if (Info.checkingPotentialConstantExpression()) |
| 3067 | return false; |
| 3068 | // FIXME: implement capture evaluation during constant expr evaluation. |
| 3069 | Info.FFDiag(E->getBeginLoc(), |
| 3070 | diag::note_unimplemented_constexpr_lambda_feature_ast) |
| 3071 | << "captures not currently allowed"; |
| 3072 | return false; |
| 3073 | } |
| 3074 | return true; |
| 3075 | } |
| 3076 | |
| 3077 | // Dig out the initializer, and use the declaration which it's attached to. |
| 3078 | // FIXME: We should eventually check whether the variable has a reachable |
| 3079 | // initializing declaration. |
| 3080 | const Expr *Init = VD->getAnyInitializer(VD); |
| 3081 | if (!Init) { |
| 3082 | // Don't diagnose during potential constant expression checking; an |
| 3083 | // initializer might be added later. |
| 3084 | if (!Info.checkingPotentialConstantExpression()) { |
| 3085 | Info.FFDiag(E, diag::note_constexpr_var_init_unknown, 1) |
| 3086 | << VD; |
| 3087 | Info.Note(VD->getLocation(), diag::note_declared_at); |
| 3088 | } |
| 3089 | return false; |
| 3090 | } |
| 3091 | |
| 3092 | if (Init->isValueDependent()) { |
| 3093 | // The DeclRefExpr is not value-dependent, but the variable it refers to |
| 3094 | // has a value-dependent initializer. This should only happen in |
| 3095 | // constant-folding cases, where the variable is not actually of a suitable |
| 3096 | // type for use in a constant expression (otherwise the DeclRefExpr would |
| 3097 | // have been value-dependent too), so diagnose that. |
| 3098 | assert(!VD->mightBeUsableInConstantExpressions(Info.Ctx))((!VD->mightBeUsableInConstantExpressions(Info.Ctx)) ? static_cast <void> (0) : __assert_fail ("!VD->mightBeUsableInConstantExpressions(Info.Ctx)" , "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 3098, __PRETTY_FUNCTION__)); |
| 3099 | if (!Info.checkingPotentialConstantExpression()) { |
| 3100 | Info.FFDiag(E, Info.getLangOpts().CPlusPlus11 |
| 3101 | ? diag::note_constexpr_ltor_non_constexpr |
| 3102 | : diag::note_constexpr_ltor_non_integral, 1) |
| 3103 | << VD << VD->getType(); |
| 3104 | Info.Note(VD->getLocation(), diag::note_declared_at); |
| 3105 | } |
| 3106 | return false; |
| 3107 | } |
| 3108 | |
| 3109 | // If we're currently evaluating the initializer of this declaration, use that |
| 3110 | // in-flight value. |
| 3111 | if (Info.EvaluatingDecl.dyn_cast<const ValueDecl*>() == VD) { |
| 3112 | Result = Info.EvaluatingDeclValue; |
| 3113 | return true; |
| 3114 | } |
| 3115 | |
| 3116 | // Check that we can fold the initializer. In C++, we will have already done |
| 3117 | // this in the cases where it matters for conformance. |
| 3118 | SmallVector<PartialDiagnosticAt, 8> Notes; |
| 3119 | if (!VD->evaluateValue(Notes)) { |
| 3120 | Info.FFDiag(E, diag::note_constexpr_var_init_non_constant, |
| 3121 | Notes.size() + 1) << VD; |
| 3122 | Info.Note(VD->getLocation(), diag::note_declared_at); |
| 3123 | Info.addNotes(Notes); |
| 3124 | return false; |
| 3125 | } |
| 3126 | |
| 3127 | // Check that the variable is actually usable in constant expressions. |
| 3128 | if (!VD->checkInitIsICE()) { |
| 3129 | Info.CCEDiag(E, diag::note_constexpr_var_init_non_constant, |
| 3130 | Notes.size() + 1) << VD; |
| 3131 | Info.Note(VD->getLocation(), diag::note_declared_at); |
| 3132 | Info.addNotes(Notes); |
| 3133 | } |
| 3134 | |
| 3135 | // Never use the initializer of a weak variable, not even for constant |
| 3136 | // folding. We can't be sure that this is the definition that will be used. |
| 3137 | if (VD->isWeak()) { |
| 3138 | Info.FFDiag(E, diag::note_constexpr_var_init_weak) << VD; |
| 3139 | Info.Note(VD->getLocation(), diag::note_declared_at); |
| 3140 | return false; |
| 3141 | } |
| 3142 | |
| 3143 | Result = VD->getEvaluatedValue(); |
| 3144 | return true; |
| 3145 | } |
| 3146 | |
| 3147 | static bool IsConstNonVolatile(QualType T) { |
| 3148 | Qualifiers Quals = T.getQualifiers(); |
| 3149 | return Quals.hasConst() && !Quals.hasVolatile(); |
| 3150 | } |
| 3151 | |
| 3152 | /// Get the base index of the given base class within an APValue representing |
| 3153 | /// the given derived class. |
| 3154 | static unsigned getBaseIndex(const CXXRecordDecl *Derived, |
| 3155 | const CXXRecordDecl *Base) { |
| 3156 | Base = Base->getCanonicalDecl(); |
| 3157 | unsigned Index = 0; |
| 3158 | for (CXXRecordDecl::base_class_const_iterator I = Derived->bases_begin(), |
| 3159 | E = Derived->bases_end(); I != E; ++I, ++Index) { |
| 3160 | if (I->getType()->getAsCXXRecordDecl()->getCanonicalDecl() == Base) |
| 3161 | return Index; |
| 3162 | } |
| 3163 | |
| 3164 | llvm_unreachable("base class missing from derived class's bases list")::llvm::llvm_unreachable_internal("base class missing from derived class's bases list" , "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 3164); |
| 3165 | } |
| 3166 | |
| 3167 | /// Extract the value of a character from a string literal. |
| 3168 | static APSInt extractStringLiteralCharacter(EvalInfo &Info, const Expr *Lit, |
| 3169 | uint64_t Index) { |
| 3170 | assert(!isa<SourceLocExpr>(Lit) &&((!isa<SourceLocExpr>(Lit) && "SourceLocExpr should have already been converted to a StringLiteral" ) ? static_cast<void> (0) : __assert_fail ("!isa<SourceLocExpr>(Lit) && \"SourceLocExpr should have already been converted to a StringLiteral\"" , "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 3171, __PRETTY_FUNCTION__)) |
| 3171 | "SourceLocExpr should have already been converted to a StringLiteral")((!isa<SourceLocExpr>(Lit) && "SourceLocExpr should have already been converted to a StringLiteral" ) ? static_cast<void> (0) : __assert_fail ("!isa<SourceLocExpr>(Lit) && \"SourceLocExpr should have already been converted to a StringLiteral\"" , "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 3171, __PRETTY_FUNCTION__)); |
| 3172 | |
| 3173 | // FIXME: Support MakeStringConstant |
| 3174 | if (const auto *ObjCEnc = dyn_cast<ObjCEncodeExpr>(Lit)) { |
| 3175 | std::string Str; |
| 3176 | Info.Ctx.getObjCEncodingForType(ObjCEnc->getEncodedType(), Str); |
| 3177 | assert(Index <= Str.size() && "Index too large")((Index <= Str.size() && "Index too large") ? static_cast <void> (0) : __assert_fail ("Index <= Str.size() && \"Index too large\"" , "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 3177, __PRETTY_FUNCTION__)); |
| 3178 | return APSInt::getUnsigned(Str.c_str()[Index]); |
| 3179 | } |
| 3180 | |
| 3181 | if (auto PE = dyn_cast<PredefinedExpr>(Lit)) |
| 3182 | Lit = PE->getFunctionName(); |
| 3183 | const StringLiteral *S = cast<StringLiteral>(Lit); |
| 3184 | const ConstantArrayType *CAT = |
| 3185 | Info.Ctx.getAsConstantArrayType(S->getType()); |
| 3186 | assert(CAT && "string literal isn't an array")((CAT && "string literal isn't an array") ? static_cast <void> (0) : __assert_fail ("CAT && \"string literal isn't an array\"" , "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 3186, __PRETTY_FUNCTION__)); |
| 3187 | QualType CharType = CAT->getElementType(); |
| 3188 | assert(CharType->isIntegerType() && "unexpected character type")((CharType->isIntegerType() && "unexpected character type" ) ? static_cast<void> (0) : __assert_fail ("CharType->isIntegerType() && \"unexpected character type\"" , "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 3188, __PRETTY_FUNCTION__)); |
| 3189 | |
| 3190 | APSInt Value(S->getCharByteWidth() * Info.Ctx.getCharWidth(), |
| 3191 | CharType->isUnsignedIntegerType()); |
| 3192 | if (Index < S->getLength()) |
| 3193 | Value = S->getCodeUnit(Index); |
| 3194 | return Value; |
| 3195 | } |
| 3196 | |
| 3197 | // Expand a string literal into an array of characters. |
| 3198 | // |
| 3199 | // FIXME: This is inefficient; we should probably introduce something similar |
| 3200 | // to the LLVM ConstantDataArray to make this cheaper. |
| 3201 | static void expandStringLiteral(EvalInfo &Info, const StringLiteral *S, |
| 3202 | APValue &Result, |
| 3203 | QualType AllocType = QualType()) { |
| 3204 | const ConstantArrayType *CAT = Info.Ctx.getAsConstantArrayType( |
| 3205 | AllocType.isNull() ? S->getType() : AllocType); |
| 3206 | assert(CAT && "string literal isn't an array")((CAT && "string literal isn't an array") ? static_cast <void> (0) : __assert_fail ("CAT && \"string literal isn't an array\"" , "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 3206, __PRETTY_FUNCTION__)); |
| 3207 | QualType CharType = CAT->getElementType(); |
| 3208 | assert(CharType->isIntegerType() && "unexpected character type")((CharType->isIntegerType() && "unexpected character type" ) ? static_cast<void> (0) : __assert_fail ("CharType->isIntegerType() && \"unexpected character type\"" , "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 3208, __PRETTY_FUNCTION__)); |
| 3209 | |
| 3210 | unsigned Elts = CAT->getSize().getZExtValue(); |
| 3211 | Result = APValue(APValue::UninitArray(), |
| 3212 | std::min(S->getLength(), Elts), Elts); |
| 3213 | APSInt Value(S->getCharByteWidth() * Info.Ctx.getCharWidth(), |
| 3214 | CharType->isUnsignedIntegerType()); |
| 3215 | if (Result.hasArrayFiller()) |
| 3216 | Result.getArrayFiller() = APValue(Value); |
| 3217 | for (unsigned I = 0, N = Result.getArrayInitializedElts(); I != N; ++I) { |
| 3218 | Value = S->getCodeUnit(I); |
| 3219 | Result.getArrayInitializedElt(I) = APValue(Value); |
| 3220 | } |
| 3221 | } |
| 3222 | |
| 3223 | // Expand an array so that it has more than Index filled elements. |
| 3224 | static void expandArray(APValue &Array, unsigned Index) { |
| 3225 | unsigned Size = Array.getArraySize(); |
| 3226 | assert(Index < Size)((Index < Size) ? static_cast<void> (0) : __assert_fail ("Index < Size", "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 3226, __PRETTY_FUNCTION__)); |
| 3227 | |
| 3228 | // Always at least double the number of elements for which we store a value. |
| 3229 | unsigned OldElts = Array.getArrayInitializedElts(); |
| 3230 | unsigned NewElts = std::max(Index+1, OldElts * 2); |
| 3231 | NewElts = std::min(Size, std::max(NewElts, 8u)); |
| 3232 | |
| 3233 | // Copy the data across. |
| 3234 | APValue NewValue(APValue::UninitArray(), NewElts, Size); |
| 3235 | for (unsigned I = 0; I != OldElts; ++I) |
| 3236 | NewValue.getArrayInitializedElt(I).swap(Array.getArrayInitializedElt(I)); |
| 3237 | for (unsigned I = OldElts; I != NewElts; ++I) |
| 3238 | NewValue.getArrayInitializedElt(I) = Array.getArrayFiller(); |
| 3239 | if (NewValue.hasArrayFiller()) |
| 3240 | NewValue.getArrayFiller() = Array.getArrayFiller(); |
| 3241 | Array.swap(NewValue); |
| 3242 | } |
| 3243 | |
| 3244 | /// Determine whether a type would actually be read by an lvalue-to-rvalue |
| 3245 | /// conversion. If it's of class type, we may assume that the copy operation |
| 3246 | /// is trivial. Note that this is never true for a union type with fields |
| 3247 | /// (because the copy always "reads" the active member) and always true for |
| 3248 | /// a non-class type. |
| 3249 | static bool isReadByLvalueToRvalueConversion(const CXXRecordDecl *RD); |
| 3250 | static bool isReadByLvalueToRvalueConversion(QualType T) { |
| 3251 | CXXRecordDecl *RD = T->getBaseElementTypeUnsafe()->getAsCXXRecordDecl(); |
| 3252 | return !RD || isReadByLvalueToRvalueConversion(RD); |
| 3253 | } |
| 3254 | static bool isReadByLvalueToRvalueConversion(const CXXRecordDecl *RD) { |
| 3255 | // FIXME: A trivial copy of a union copies the object representation, even if |
| 3256 | // the union is empty. |
| 3257 | if (RD->isUnion()) |
| 3258 | return !RD->field_empty(); |
| 3259 | if (RD->isEmpty()) |
| 3260 | return false; |
| 3261 | |
| 3262 | for (auto *Field : RD->fields()) |
| 3263 | if (!Field->isUnnamedBitfield() && |
| 3264 | isReadByLvalueToRvalueConversion(Field->getType())) |
| 3265 | return true; |
| 3266 | |
| 3267 | for (auto &BaseSpec : RD->bases()) |
| 3268 | if (isReadByLvalueToRvalueConversion(BaseSpec.getType())) |
| 3269 | return true; |
| 3270 | |
| 3271 | return false; |
| 3272 | } |
| 3273 | |
| 3274 | /// Diagnose an attempt to read from any unreadable field within the specified |
| 3275 | /// type, which might be a class type. |
| 3276 | static bool diagnoseMutableFields(EvalInfo &Info, const Expr *E, AccessKinds AK, |
| 3277 | QualType T) { |
| 3278 | CXXRecordDecl *RD = T->getBaseElementTypeUnsafe()->getAsCXXRecordDecl(); |
| 3279 | if (!RD) |
| 3280 | return false; |
| 3281 | |
| 3282 | if (!RD->hasMutableFields()) |
| 3283 | return false; |
| 3284 | |
| 3285 | for (auto *Field : RD->fields()) { |
| 3286 | // If we're actually going to read this field in some way, then it can't |
| 3287 | // be mutable. If we're in a union, then assigning to a mutable field |
| 3288 | // (even an empty one) can change the active member, so that's not OK. |
| 3289 | // FIXME: Add core issue number for the union case. |
| 3290 | if (Field->isMutable() && |
| 3291 | (RD->isUnion() || isReadByLvalueToRvalueConversion(Field->getType()))) { |
| 3292 | Info.FFDiag(E, diag::note_constexpr_access_mutable, 1) << AK << Field; |
| 3293 | Info.Note(Field->getLocation(), diag::note_declared_at); |
| 3294 | return true; |
| 3295 | } |
| 3296 | |
| 3297 | if (diagnoseMutableFields(Info, E, AK, Field->getType())) |
| 3298 | return true; |
| 3299 | } |
| 3300 | |
| 3301 | for (auto &BaseSpec : RD->bases()) |
| 3302 | if (diagnoseMutableFields(Info, E, AK, BaseSpec.getType())) |
| 3303 | return true; |
| 3304 | |
| 3305 | // All mutable fields were empty, and thus not actually read. |
| 3306 | return false; |
| 3307 | } |
| 3308 | |
| 3309 | static bool lifetimeStartedInEvaluation(EvalInfo &Info, |
| 3310 | APValue::LValueBase Base, |
| 3311 | bool MutableSubobject = false) { |
| 3312 | // A temporary we created. |
| 3313 | if (Base.getCallIndex()) |
| 3314 | return true; |
| 3315 | |
| 3316 | auto *Evaluating = Info.EvaluatingDecl.dyn_cast<const ValueDecl*>(); |
| 3317 | if (!Evaluating) |
| 3318 | return false; |
| 3319 | |
| 3320 | auto *BaseD = Base.dyn_cast<const ValueDecl*>(); |
| 3321 | |
| 3322 | switch (Info.IsEvaluatingDecl) { |
| 3323 | case EvalInfo::EvaluatingDeclKind::None: |
| 3324 | return false; |
| 3325 | |
| 3326 | case EvalInfo::EvaluatingDeclKind::Ctor: |
| 3327 | // The variable whose initializer we're evaluating. |
| 3328 | if (BaseD) |
| 3329 | return declaresSameEntity(Evaluating, BaseD); |
| 3330 | |
| 3331 | // A temporary lifetime-extended by the variable whose initializer we're |
| 3332 | // evaluating. |
| 3333 | if (auto *BaseE = Base.dyn_cast<const Expr *>()) |
| 3334 | if (auto *BaseMTE = dyn_cast<MaterializeTemporaryExpr>(BaseE)) |
| 3335 | return declaresSameEntity(BaseMTE->getExtendingDecl(), Evaluating); |
| 3336 | return false; |
| 3337 | |
| 3338 | case EvalInfo::EvaluatingDeclKind::Dtor: |
| 3339 | // C++2a [expr.const]p6: |
| 3340 | // [during constant destruction] the lifetime of a and its non-mutable |
| 3341 | // subobjects (but not its mutable subobjects) [are] considered to start |
| 3342 | // within e. |
| 3343 | // |
| 3344 | // FIXME: We can meaningfully extend this to cover non-const objects, but |
| 3345 | // we will need special handling: we should be able to access only |
| 3346 | // subobjects of such objects that are themselves declared const. |
| 3347 | if (!BaseD || |
| 3348 | !(BaseD->getType().isConstQualified() || |
| 3349 | BaseD->getType()->isReferenceType()) || |
| 3350 | MutableSubobject) |
| 3351 | return false; |
| 3352 | return declaresSameEntity(Evaluating, BaseD); |
| 3353 | } |
| 3354 | |
| 3355 | llvm_unreachable("unknown evaluating decl kind")::llvm::llvm_unreachable_internal("unknown evaluating decl kind" , "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 3355); |
| 3356 | } |
| 3357 | |
| 3358 | namespace { |
| 3359 | /// A handle to a complete object (an object that is not a subobject of |
| 3360 | /// another object). |
| 3361 | struct CompleteObject { |
| 3362 | /// The identity of the object. |
| 3363 | APValue::LValueBase Base; |
| 3364 | /// The value of the complete object. |
| 3365 | APValue *Value; |
| 3366 | /// The type of the complete object. |
| 3367 | QualType Type; |
| 3368 | |
| 3369 | CompleteObject() : Value(nullptr) {} |
| 3370 | CompleteObject(APValue::LValueBase Base, APValue *Value, QualType Type) |
| 3371 | : Base(Base), Value(Value), Type(Type) {} |
| 3372 | |
| 3373 | bool mayAccessMutableMembers(EvalInfo &Info, AccessKinds AK) const { |
| 3374 | // If this isn't a "real" access (eg, if it's just accessing the type |
| 3375 | // info), allow it. We assume the type doesn't change dynamically for |
| 3376 | // subobjects of constexpr objects (even though we'd hit UB here if it |
| 3377 | // did). FIXME: Is this right? |
| 3378 | if (!isAnyAccess(AK)) |
| 3379 | return true; |
| 3380 | |
| 3381 | // In C++14 onwards, it is permitted to read a mutable member whose |
| 3382 | // lifetime began within the evaluation. |
| 3383 | // FIXME: Should we also allow this in C++11? |
| 3384 | if (!Info.getLangOpts().CPlusPlus14) |
| 3385 | return false; |
| 3386 | return lifetimeStartedInEvaluation(Info, Base, /*MutableSubobject*/true); |
| 3387 | } |
| 3388 | |
| 3389 | explicit operator bool() const { return !Type.isNull(); } |
| 3390 | }; |
| 3391 | } // end anonymous namespace |
| 3392 | |
| 3393 | static QualType getSubobjectType(QualType ObjType, QualType SubobjType, |
| 3394 | bool IsMutable = false) { |
| 3395 | // C++ [basic.type.qualifier]p1: |
| 3396 | // - A const object is an object of type const T or a non-mutable subobject |
| 3397 | // of a const object. |
| 3398 | if (ObjType.isConstQualified() && !IsMutable) |
| 3399 | SubobjType.addConst(); |
| 3400 | // - A volatile object is an object of type const T or a subobject of a |
| 3401 | // volatile object. |
| 3402 | if (ObjType.isVolatileQualified()) |
| 3403 | SubobjType.addVolatile(); |
| 3404 | return SubobjType; |
| 3405 | } |
| 3406 | |
| 3407 | /// Find the designated sub-object of an rvalue. |
| 3408 | template<typename SubobjectHandler> |
| 3409 | typename SubobjectHandler::result_type |
| 3410 | findSubobject(EvalInfo &Info, const Expr *E, const CompleteObject &Obj, |
| 3411 | const SubobjectDesignator &Sub, SubobjectHandler &handler) { |
| 3412 | if (Sub.Invalid) |
| 3413 | // A diagnostic will have already been produced. |
| 3414 | return handler.failed(); |
| 3415 | if (Sub.isOnePastTheEnd() || Sub.isMostDerivedAnUnsizedArray()) { |
| 3416 | if (Info.getLangOpts().CPlusPlus11) |
| 3417 | Info.FFDiag(E, Sub.isOnePastTheEnd() |
| 3418 | ? diag::note_constexpr_access_past_end |
| 3419 | : diag::note_constexpr_access_unsized_array) |
| 3420 | << handler.AccessKind; |
| 3421 | else |
| 3422 | Info.FFDiag(E); |
| 3423 | return handler.failed(); |
| 3424 | } |
| 3425 | |
| 3426 | APValue *O = Obj.Value; |
| 3427 | QualType ObjType = Obj.Type; |
| 3428 | const FieldDecl *LastField = nullptr; |
| 3429 | const FieldDecl *VolatileField = nullptr; |
| 3430 | |
| 3431 | // Walk the designator's path to find the subobject. |
| 3432 | for (unsigned I = 0, N = Sub.Entries.size(); /**/; ++I) { |
| 3433 | // Reading an indeterminate value is undefined, but assigning over one is OK. |
| 3434 | if ((O->isAbsent() && !(handler.AccessKind == AK_Construct && I == N)) || |
| 3435 | (O->isIndeterminate() && |
| 3436 | !isValidIndeterminateAccess(handler.AccessKind))) { |
| 3437 | if (!Info.checkingPotentialConstantExpression()) |
| 3438 | Info.FFDiag(E, diag::note_constexpr_access_uninit) |
| 3439 | << handler.AccessKind << O->isIndeterminate(); |
| 3440 | return handler.failed(); |
| 3441 | } |
| 3442 | |
| 3443 | // C++ [class.ctor]p5, C++ [class.dtor]p5: |
| 3444 | // const and volatile semantics are not applied on an object under |
| 3445 | // {con,de}struction. |
| 3446 | if ((ObjType.isConstQualified() || ObjType.isVolatileQualified()) && |
| 3447 | ObjType->isRecordType() && |
| 3448 | Info.isEvaluatingCtorDtor( |
| 3449 | Obj.Base, llvm::makeArrayRef(Sub.Entries.begin(), |
| 3450 | Sub.Entries.begin() + I)) != |
| 3451 | ConstructionPhase::None) { |
| 3452 | ObjType = Info.Ctx.getCanonicalType(ObjType); |
| 3453 | ObjType.removeLocalConst(); |
| 3454 | ObjType.removeLocalVolatile(); |
| 3455 | } |
| 3456 | |
| 3457 | // If this is our last pass, check that the final object type is OK. |
| 3458 | if (I == N || (I == N - 1 && ObjType->isAnyComplexType())) { |
| 3459 | // Accesses to volatile objects are prohibited. |
| 3460 | if (ObjType.isVolatileQualified() && isFormalAccess(handler.AccessKind)) { |
| 3461 | if (Info.getLangOpts().CPlusPlus) { |
| 3462 | int DiagKind; |
| 3463 | SourceLocation Loc; |
| 3464 | const NamedDecl *Decl = nullptr; |
| 3465 | if (VolatileField) { |
| 3466 | DiagKind = 2; |
| 3467 | Loc = VolatileField->getLocation(); |
| 3468 | Decl = VolatileField; |
| 3469 | } else if (auto *VD = Obj.Base.dyn_cast<const ValueDecl*>()) { |
| 3470 | DiagKind = 1; |
| 3471 | Loc = VD->getLocation(); |
| 3472 | Decl = VD; |
| 3473 | } else { |
| 3474 | DiagKind = 0; |
| 3475 | if (auto *E = Obj.Base.dyn_cast<const Expr *>()) |
| 3476 | Loc = E->getExprLoc(); |
| 3477 | } |
| 3478 | Info.FFDiag(E, diag::note_constexpr_access_volatile_obj, 1) |
| 3479 | << handler.AccessKind << DiagKind << Decl; |
| 3480 | Info.Note(Loc, diag::note_constexpr_volatile_here) << DiagKind; |
| 3481 | } else { |
| 3482 | Info.FFDiag(E, diag::note_invalid_subexpr_in_const_expr); |
| 3483 | } |
| 3484 | return handler.failed(); |
| 3485 | } |
| 3486 | |
| 3487 | // If we are reading an object of class type, there may still be more |
| 3488 | // things we need to check: if there are any mutable subobjects, we |
| 3489 | // cannot perform this read. (This only happens when performing a trivial |
| 3490 | // copy or assignment.) |
| 3491 | if (ObjType->isRecordType() && |
| 3492 | !Obj.mayAccessMutableMembers(Info, handler.AccessKind) && |
| 3493 | diagnoseMutableFields(Info, E, handler.AccessKind, ObjType)) |
| 3494 | return handler.failed(); |
| 3495 | } |
| 3496 | |
| 3497 | if (I == N) { |
| 3498 | if (!handler.found(*O, ObjType)) |
| 3499 | return false; |
| 3500 | |
| 3501 | // If we modified a bit-field, truncate it to the right width. |
| 3502 | if (isModification(handler.AccessKind) && |
| 3503 | LastField && LastField->isBitField() && |
| 3504 | !truncateBitfieldValue(Info, E, *O, LastField)) |
| 3505 | return false; |
| 3506 | |
| 3507 | return true; |
| 3508 | } |
| 3509 | |
| 3510 | LastField = nullptr; |
| 3511 | if (ObjType->isArrayType()) { |
| 3512 | // Next subobject is an array element. |
| 3513 | const ConstantArrayType *CAT = Info.Ctx.getAsConstantArrayType(ObjType); |
| 3514 | assert(CAT && "vla in literal type?")((CAT && "vla in literal type?") ? static_cast<void > (0) : __assert_fail ("CAT && \"vla in literal type?\"" , "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 3514, __PRETTY_FUNCTION__)); |
| 3515 | uint64_t Index = Sub.Entries[I].getAsArrayIndex(); |
| 3516 | if (CAT->getSize().ule(Index)) { |
| 3517 | // Note, it should not be possible to form a pointer with a valid |
| 3518 | // designator which points more than one past the end of the array. |
| 3519 | if (Info.getLangOpts().CPlusPlus11) |
| 3520 | Info.FFDiag(E, diag::note_constexpr_access_past_end) |
| 3521 | << handler.AccessKind; |
| 3522 | else |
| 3523 | Info.FFDiag(E); |
| 3524 | return handler.failed(); |
| 3525 | } |
| 3526 | |
| 3527 | ObjType = CAT->getElementType(); |
| 3528 | |
| 3529 | if (O->getArrayInitializedElts() > Index) |
| 3530 | O = &O->getArrayInitializedElt(Index); |
| 3531 | else if (!isRead(handler.AccessKind)) { |
| 3532 | expandArray(*O, Index); |
| 3533 | O = &O->getArrayInitializedElt(Index); |
| 3534 | } else |
| 3535 | O = &O->getArrayFiller(); |
| 3536 | } else if (ObjType->isAnyComplexType()) { |
| 3537 | // Next subobject is a complex number. |
| 3538 | uint64_t Index = Sub.Entries[I].getAsArrayIndex(); |
| 3539 | if (Index > 1) { |
| 3540 | if (Info.getLangOpts().CPlusPlus11) |
| 3541 | Info.FFDiag(E, diag::note_constexpr_access_past_end) |
| 3542 | << handler.AccessKind; |
| 3543 | else |
| 3544 | Info.FFDiag(E); |
| 3545 | return handler.failed(); |
| 3546 | } |
| 3547 | |
| 3548 | ObjType = getSubobjectType( |
| 3549 | ObjType, ObjType->castAs<ComplexType>()->getElementType()); |
| 3550 | |
| 3551 | assert(I == N - 1 && "extracting subobject of scalar?")((I == N - 1 && "extracting subobject of scalar?") ? static_cast <void> (0) : __assert_fail ("I == N - 1 && \"extracting subobject of scalar?\"" , "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 3551, __PRETTY_FUNCTION__)); |
| 3552 | if (O->isComplexInt()) { |
| 3553 | return handler.found(Index ? O->getComplexIntImag() |
| 3554 | : O->getComplexIntReal(), ObjType); |
| 3555 | } else { |
| 3556 | assert(O->isComplexFloat())((O->isComplexFloat()) ? static_cast<void> (0) : __assert_fail ("O->isComplexFloat()", "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 3556, __PRETTY_FUNCTION__)); |
| 3557 | return handler.found(Index ? O->getComplexFloatImag() |
| 3558 | : O->getComplexFloatReal(), ObjType); |
| 3559 | } |
| 3560 | } else if (const FieldDecl *Field = getAsField(Sub.Entries[I])) { |
| 3561 | if (Field->isMutable() && |
| 3562 | !Obj.mayAccessMutableMembers(Info, handler.AccessKind)) { |
| 3563 | Info.FFDiag(E, diag::note_constexpr_access_mutable, 1) |
| 3564 | << handler.AccessKind << Field; |
| 3565 | Info.Note(Field->getLocation(), diag::note_declared_at); |
| 3566 | return handler.failed(); |
| 3567 | } |
| 3568 | |
| 3569 | // Next subobject is a class, struct or union field. |
| 3570 | RecordDecl *RD = ObjType->castAs<RecordType>()->getDecl(); |
| 3571 | if (RD->isUnion()) { |
| 3572 | const FieldDecl *UnionField = O->getUnionField(); |
| 3573 | if (!UnionField || |
| 3574 | UnionField->getCanonicalDecl() != Field->getCanonicalDecl()) { |
| 3575 | if (I == N - 1 && handler.AccessKind == AK_Construct) { |
| 3576 | // Placement new onto an inactive union member makes it active. |
| 3577 | O->setUnion(Field, APValue()); |
| 3578 | } else { |
| 3579 | // FIXME: If O->getUnionValue() is absent, report that there's no |
| 3580 | // active union member rather than reporting the prior active union |
| 3581 | // member. We'll need to fix nullptr_t to not use APValue() as its |
| 3582 | // representation first. |
| 3583 | Info.FFDiag(E, diag::note_constexpr_access_inactive_union_member) |
| 3584 | << handler.AccessKind << Field << !UnionField << UnionField; |
| 3585 | return handler.failed(); |
| 3586 | } |
| 3587 | } |
| 3588 | O = &O->getUnionValue(); |
| 3589 | } else |
| 3590 | O = &O->getStructField(Field->getFieldIndex()); |
| 3591 | |
| 3592 | ObjType = getSubobjectType(ObjType, Field->getType(), Field->isMutable()); |
| 3593 | LastField = Field; |
| 3594 | if (Field->getType().isVolatileQualified()) |
| 3595 | VolatileField = Field; |
| 3596 | } else { |
| 3597 | // Next subobject is a base class. |
| 3598 | const CXXRecordDecl *Derived = ObjType->getAsCXXRecordDecl(); |
| 3599 | const CXXRecordDecl *Base = getAsBaseClass(Sub.Entries[I]); |
| 3600 | O = &O->getStructBase(getBaseIndex(Derived, Base)); |
| 3601 | |
| 3602 | ObjType = getSubobjectType(ObjType, Info.Ctx.getRecordType(Base)); |
| 3603 | } |
| 3604 | } |
| 3605 | } |
| 3606 | |
| 3607 | namespace { |
| 3608 | struct ExtractSubobjectHandler { |
| 3609 | EvalInfo &Info; |
| 3610 | const Expr *E; |
| 3611 | APValue &Result; |
| 3612 | const AccessKinds AccessKind; |
| 3613 | |
| 3614 | typedef bool result_type; |
| 3615 | bool failed() { return false; } |
| 3616 | bool found(APValue &Subobj, QualType SubobjType) { |
| 3617 | Result = Subobj; |
| 3618 | if (AccessKind == AK_ReadObjectRepresentation) |
| 3619 | return true; |
| 3620 | return CheckFullyInitialized(Info, E->getExprLoc(), SubobjType, Result); |
| 3621 | } |
| 3622 | bool found(APSInt &Value, QualType SubobjType) { |
| 3623 | Result = APValue(Value); |
| 3624 | return true; |
| 3625 | } |
| 3626 | bool found(APFloat &Value, QualType SubobjType) { |
| 3627 | Result = APValue(Value); |
| 3628 | return true; |
| 3629 | } |
| 3630 | }; |
| 3631 | } // end anonymous namespace |
| 3632 | |
| 3633 | /// Extract the designated sub-object of an rvalue. |
| 3634 | static bool extractSubobject(EvalInfo &Info, const Expr *E, |
| 3635 | const CompleteObject &Obj, |
| 3636 | const SubobjectDesignator &Sub, APValue &Result, |
| 3637 | AccessKinds AK = AK_Read) { |
| 3638 | assert(AK == AK_Read || AK == AK_ReadObjectRepresentation)((AK == AK_Read || AK == AK_ReadObjectRepresentation) ? static_cast <void> (0) : __assert_fail ("AK == AK_Read || AK == AK_ReadObjectRepresentation" , "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 3638, __PRETTY_FUNCTION__)); |
| 3639 | ExtractSubobjectHandler Handler = {Info, E, Result, AK}; |
| 3640 | return findSubobject(Info, E, Obj, Sub, Handler); |
| 3641 | } |
| 3642 | |
| 3643 | namespace { |
| 3644 | struct ModifySubobjectHandler { |
| 3645 | EvalInfo &Info; |
| 3646 | APValue &NewVal; |
| 3647 | const Expr *E; |
| 3648 | |
| 3649 | typedef bool result_type; |
| 3650 | static const AccessKinds AccessKind = AK_Assign; |
| 3651 | |
| 3652 | bool checkConst(QualType QT) { |
| 3653 | // Assigning to a const object has undefined behavior. |
| 3654 | if (QT.isConstQualified()) { |
| 3655 | Info.FFDiag(E, diag::note_constexpr_modify_const_type) << QT; |
| 3656 | return false; |
| 3657 | } |
| 3658 | return true; |
| 3659 | } |
| 3660 | |
| 3661 | bool failed() { return false; } |
| 3662 | bool found(APValue &Subobj, QualType SubobjType) { |
| 3663 | if (!checkConst(SubobjType)) |
| 3664 | return false; |
| 3665 | // We've been given ownership of NewVal, so just swap it in. |
| 3666 | Subobj.swap(NewVal); |
| 3667 | return true; |
| 3668 | } |
| 3669 | bool found(APSInt &Value, QualType SubobjType) { |
| 3670 | if (!checkConst(SubobjType)) |
| 3671 | return false; |
| 3672 | if (!NewVal.isInt()) { |
| 3673 | // Maybe trying to write a cast pointer value into a complex? |
| 3674 | Info.FFDiag(E); |
| 3675 | return false; |
| 3676 | } |
| 3677 | Value = NewVal.getInt(); |
| 3678 | return true; |
| 3679 | } |
| 3680 | bool found(APFloat &Value, QualType SubobjType) { |
| 3681 | if (!checkConst(SubobjType)) |
| 3682 | return false; |
| 3683 | Value = NewVal.getFloat(); |
| 3684 | return true; |
| 3685 | } |
| 3686 | }; |
| 3687 | } // end anonymous namespace |
| 3688 | |
| 3689 | const AccessKinds ModifySubobjectHandler::AccessKind; |
| 3690 | |
| 3691 | /// Update the designated sub-object of an rvalue to the given value. |
| 3692 | static bool modifySubobject(EvalInfo &Info, const Expr *E, |
| 3693 | const CompleteObject &Obj, |
| 3694 | const SubobjectDesignator &Sub, |
| 3695 | APValue &NewVal) { |
| 3696 | ModifySubobjectHandler Handler = { Info, NewVal, E }; |
| 3697 | return findSubobject(Info, E, Obj, Sub, Handler); |
| 3698 | } |
| 3699 | |
| 3700 | /// Find the position where two subobject designators diverge, or equivalently |
| 3701 | /// the length of the common initial subsequence. |
| 3702 | static unsigned FindDesignatorMismatch(QualType ObjType, |
| 3703 | const SubobjectDesignator &A, |
| 3704 | const SubobjectDesignator &B, |
| 3705 | bool &WasArrayIndex) { |
| 3706 | unsigned I = 0, N = std::min(A.Entries.size(), B.Entries.size()); |
| 3707 | for (/**/; I != N; ++I) { |
| 3708 | if (!ObjType.isNull() && |
| 3709 | (ObjType->isArrayType() || ObjType->isAnyComplexType())) { |
| 3710 | // Next subobject is an array element. |
| 3711 | if (A.Entries[I].getAsArrayIndex() != B.Entries[I].getAsArrayIndex()) { |
| 3712 | WasArrayIndex = true; |
| 3713 | return I; |
| 3714 | } |
| 3715 | if (ObjType->isAnyComplexType()) |
| 3716 | ObjType = ObjType->castAs<ComplexType>()->getElementType(); |
| 3717 | else |
| 3718 | ObjType = ObjType->castAsArrayTypeUnsafe()->getElementType(); |
| 3719 | } else { |
| 3720 | if (A.Entries[I].getAsBaseOrMember() != |
| 3721 | B.Entries[I].getAsBaseOrMember()) { |
| 3722 | WasArrayIndex = false; |
| 3723 | return I; |
| 3724 | } |
| 3725 | if (const FieldDecl *FD = getAsField(A.Entries[I])) |
| 3726 | // Next subobject is a field. |
| 3727 | ObjType = FD->getType(); |
| 3728 | else |
| 3729 | // Next subobject is a base class. |
| 3730 | ObjType = QualType(); |
| 3731 | } |
| 3732 | } |
| 3733 | WasArrayIndex = false; |
| 3734 | return I; |
| 3735 | } |
| 3736 | |
| 3737 | /// Determine whether the given subobject designators refer to elements of the |
| 3738 | /// same array object. |
| 3739 | static bool AreElementsOfSameArray(QualType ObjType, |
| 3740 | const SubobjectDesignator &A, |
| 3741 | const SubobjectDesignator &B) { |
| 3742 | if (A.Entries.size() != B.Entries.size()) |
| 3743 | return false; |
| 3744 | |
| 3745 | bool IsArray = A.MostDerivedIsArrayElement; |
| 3746 | if (IsArray && A.MostDerivedPathLength != A.Entries.size()) |
| 3747 | // A is a subobject of the array element. |
| 3748 | return false; |
| 3749 | |
| 3750 | // If A (and B) designates an array element, the last entry will be the array |
| 3751 | // index. That doesn't have to match. Otherwise, we're in the 'implicit array |
| 3752 | // of length 1' case, and the entire path must match. |
| 3753 | bool WasArrayIndex; |
| 3754 | unsigned CommonLength = FindDesignatorMismatch(ObjType, A, B, WasArrayIndex); |
| 3755 | return CommonLength >= A.Entries.size() - IsArray; |
| 3756 | } |
| 3757 | |
| 3758 | /// Find the complete object to which an LValue refers. |
| 3759 | static CompleteObject findCompleteObject(EvalInfo &Info, const Expr *E, |
| 3760 | AccessKinds AK, const LValue &LVal, |
| 3761 | QualType LValType) { |
| 3762 | if (LVal.InvalidBase) { |
| 3763 | Info.FFDiag(E); |
| 3764 | return CompleteObject(); |
| 3765 | } |
| 3766 | |
| 3767 | if (!LVal.Base) { |
| 3768 | Info.FFDiag(E, diag::note_constexpr_access_null) << AK; |
| 3769 | return CompleteObject(); |
| 3770 | } |
| 3771 | |
| 3772 | CallStackFrame *Frame = nullptr; |
| 3773 | unsigned Depth = 0; |
| 3774 | if (LVal.getLValueCallIndex()) { |
| 3775 | std::tie(Frame, Depth) = |
| 3776 | Info.getCallFrameAndDepth(LVal.getLValueCallIndex()); |
| 3777 | if (!Frame) { |
| 3778 | Info.FFDiag(E, diag::note_constexpr_lifetime_ended, 1) |
| 3779 | << AK << LVal.Base.is<const ValueDecl*>(); |
| 3780 | NoteLValueLocation(Info, LVal.Base); |
| 3781 | return CompleteObject(); |
| 3782 | } |
| 3783 | } |
| 3784 | |
| 3785 | bool IsAccess = isAnyAccess(AK); |
| 3786 | |
| 3787 | // C++11 DR1311: An lvalue-to-rvalue conversion on a volatile-qualified type |
| 3788 | // is not a constant expression (even if the object is non-volatile). We also |
| 3789 | // apply this rule to C++98, in order to conform to the expected 'volatile' |
| 3790 | // semantics. |
| 3791 | if (isFormalAccess(AK) && LValType.isVolatileQualified()) { |
| 3792 | if (Info.getLangOpts().CPlusPlus) |
| 3793 | Info.FFDiag(E, diag::note_constexpr_access_volatile_type) |
| 3794 | << AK << LValType; |
| 3795 | else |
| 3796 | Info.FFDiag(E); |
| 3797 | return CompleteObject(); |
| 3798 | } |
| 3799 | |
| 3800 | // Compute value storage location and type of base object. |
| 3801 | APValue *BaseVal = nullptr; |
| 3802 | QualType BaseType = getType(LVal.Base); |
| 3803 | |
| 3804 | if (const ConstantExpr *CE = |
| 3805 | dyn_cast_or_null<ConstantExpr>(LVal.Base.dyn_cast<const Expr *>())) { |
| 3806 | /// Nested immediate invocation have been previously removed so if we found |
| 3807 | /// a ConstantExpr it can only be the EvaluatingDecl. |
| 3808 | assert(CE->isImmediateInvocation() && CE == Info.EvaluatingDecl)((CE->isImmediateInvocation() && CE == Info.EvaluatingDecl ) ? static_cast<void> (0) : __assert_fail ("CE->isImmediateInvocation() && CE == Info.EvaluatingDecl" , "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 3808, __PRETTY_FUNCTION__)); |
| 3809 | (void)CE; |
| 3810 | BaseVal = Info.EvaluatingDeclValue; |
| 3811 | } else if (const ValueDecl *D = LVal.Base.dyn_cast<const ValueDecl *>()) { |
| 3812 | // Allow reading from a GUID declaration. |
| 3813 | if (auto *GD = dyn_cast<MSGuidDecl>(D)) { |
| 3814 | if (isModification(AK)) { |
| 3815 | // All the remaining cases do not permit modification of the object. |
| 3816 | Info.FFDiag(E, diag::note_constexpr_modify_global); |
| 3817 | return CompleteObject(); |
| 3818 | } |
| 3819 | APValue &V = GD->getAsAPValue(); |
| 3820 | if (V.isAbsent()) { |
| 3821 | Info.FFDiag(E, diag::note_constexpr_unsupported_layout) |
| 3822 | << GD->getType(); |
| 3823 | return CompleteObject(); |
| 3824 | } |
| 3825 | return CompleteObject(LVal.Base, &V, GD->getType()); |
| 3826 | } |
| 3827 | |
| 3828 | // In C++98, const, non-volatile integers initialized with ICEs are ICEs. |
| 3829 | // In C++11, constexpr, non-volatile variables initialized with constant |
| 3830 | // expressions are constant expressions too. Inside constexpr functions, |
| 3831 | // parameters are constant expressions even if they're non-const. |
| 3832 | // In C++1y, objects local to a constant expression (those with a Frame) are |
| 3833 | // both readable and writable inside constant expressions. |
| 3834 | // In C, such things can also be folded, although they are not ICEs. |
| 3835 | const VarDecl *VD = dyn_cast<VarDecl>(D); |
| 3836 | if (VD) { |
| 3837 | if (const VarDecl *VDef = VD->getDefinition(Info.Ctx)) |
| 3838 | VD = VDef; |
| 3839 | } |
| 3840 | if (!VD || VD->isInvalidDecl()) { |
| 3841 | Info.FFDiag(E); |
| 3842 | return CompleteObject(); |
| 3843 | } |
| 3844 | |
| 3845 | // In OpenCL if a variable is in constant address space it is a const value. |
| 3846 | bool IsConstant = BaseType.isConstQualified() || |
| 3847 | (Info.getLangOpts().OpenCL && |
| 3848 | BaseType.getAddressSpace() == LangAS::opencl_constant); |
| 3849 | |
| 3850 | // Unless we're looking at a local variable or argument in a constexpr call, |
| 3851 | // the variable we're reading must be const. |
| 3852 | if (!Frame) { |
| 3853 | if (Info.getLangOpts().CPlusPlus14 && |
| 3854 | lifetimeStartedInEvaluation(Info, LVal.Base)) { |
| 3855 | // OK, we can read and modify an object if we're in the process of |
| 3856 | // evaluating its initializer, because its lifetime began in this |
| 3857 | // evaluation. |
| 3858 | } else if (isModification(AK)) { |
| 3859 | // All the remaining cases do not permit modification of the object. |
| 3860 | Info.FFDiag(E, diag::note_constexpr_modify_global); |
| 3861 | return CompleteObject(); |
| 3862 | } else if (VD->isConstexpr()) { |
| 3863 | // OK, we can read this variable. |
| 3864 | } else if (BaseType->isIntegralOrEnumerationType()) { |
| 3865 | // In OpenCL if a variable is in constant address space it is a const |
| 3866 | // value. |
| 3867 | if (!IsConstant) { |
| 3868 | if (!IsAccess) |
| 3869 | return CompleteObject(LVal.getLValueBase(), nullptr, BaseType); |
| 3870 | if (Info.getLangOpts().CPlusPlus) { |
| 3871 | Info.FFDiag(E, diag::note_constexpr_ltor_non_const_int, 1) << VD; |
| 3872 | Info.Note(VD->getLocation(), diag::note_declared_at); |
| 3873 | } else { |
| 3874 | Info.FFDiag(E); |
| 3875 | } |
| 3876 | return CompleteObject(); |
| 3877 | } |
| 3878 | } else if (!IsAccess) { |
| 3879 | return CompleteObject(LVal.getLValueBase(), nullptr, BaseType); |
| 3880 | } else if (IsConstant && Info.checkingPotentialConstantExpression() && |
| 3881 | BaseType->isLiteralType(Info.Ctx) && !VD->hasDefinition()) { |
| 3882 | // This variable might end up being constexpr. Don't diagnose it yet. |
| 3883 | } else if (IsConstant) { |
| 3884 | // Keep evaluating to see what we can do. In particular, we support |
| 3885 | // folding of const floating-point types, in order to make static const |
| 3886 | // data members of such types (supported as an extension) more useful. |
| 3887 | if (Info.getLangOpts().CPlusPlus) { |
| 3888 | Info.CCEDiag(E, Info.getLangOpts().CPlusPlus11 |
| 3889 | ? diag::note_constexpr_ltor_non_constexpr |
| 3890 | : diag::note_constexpr_ltor_non_integral, 1) |
| 3891 | << VD << BaseType; |
| 3892 | Info.Note(VD->getLocation(), diag::note_declared_at); |
| 3893 | } else { |
| 3894 | Info.CCEDiag(E); |
| 3895 | } |
| 3896 | } else { |
| 3897 | // Never allow reading a non-const value. |
| 3898 | if (Info.getLangOpts().CPlusPlus) { |
| 3899 | Info.FFDiag(E, Info.getLangOpts().CPlusPlus11 |
| 3900 | ? diag::note_constexpr_ltor_non_constexpr |
| 3901 | : diag::note_constexpr_ltor_non_integral, 1) |
| 3902 | << VD << BaseType; |
| 3903 | Info.Note(VD->getLocation(), diag::note_declared_at); |
| 3904 | } else { |
| 3905 | Info.FFDiag(E); |
| 3906 | } |
| 3907 | return CompleteObject(); |
| 3908 | } |
| 3909 | } |
| 3910 | |
| 3911 | if (!evaluateVarDeclInit(Info, E, VD, Frame, BaseVal, &LVal)) |
| 3912 | return CompleteObject(); |
| 3913 | } else if (DynamicAllocLValue DA = LVal.Base.dyn_cast<DynamicAllocLValue>()) { |
| 3914 | Optional<DynAlloc*> Alloc = Info.lookupDynamicAlloc(DA); |
| 3915 | if (!Alloc) { |
| 3916 | Info.FFDiag(E, diag::note_constexpr_access_deleted_object) << AK; |
| 3917 | return CompleteObject(); |
| 3918 | } |
| 3919 | return CompleteObject(LVal.Base, &(*Alloc)->Value, |
| 3920 | LVal.Base.getDynamicAllocType()); |
| 3921 | } else { |
| 3922 | const Expr *Base = LVal.Base.dyn_cast<const Expr*>(); |
| 3923 | |
| 3924 | if (!Frame) { |
| 3925 | if (const MaterializeTemporaryExpr *MTE = |
| 3926 | dyn_cast_or_null<MaterializeTemporaryExpr>(Base)) { |
| 3927 | assert(MTE->getStorageDuration() == SD_Static &&((MTE->getStorageDuration() == SD_Static && "should have a frame for a non-global materialized temporary" ) ? static_cast<void> (0) : __assert_fail ("MTE->getStorageDuration() == SD_Static && \"should have a frame for a non-global materialized temporary\"" , "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 3928, __PRETTY_FUNCTION__)) |
| 3928 | "should have a frame for a non-global materialized temporary")((MTE->getStorageDuration() == SD_Static && "should have a frame for a non-global materialized temporary" ) ? static_cast<void> (0) : __assert_fail ("MTE->getStorageDuration() == SD_Static && \"should have a frame for a non-global materialized temporary\"" , "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 3928, __PRETTY_FUNCTION__)); |
| 3929 | |
| 3930 | // Per C++1y [expr.const]p2: |
| 3931 | // an lvalue-to-rvalue conversion [is not allowed unless it applies to] |
| 3932 | // - a [...] glvalue of integral or enumeration type that refers to |
| 3933 | // a non-volatile const object [...] |
| 3934 | // [...] |
| 3935 | // - a [...] glvalue of literal type that refers to a non-volatile |
| 3936 | // object whose lifetime began within the evaluation of e. |
| 3937 | // |
| 3938 | // C++11 misses the 'began within the evaluation of e' check and |
| 3939 | // instead allows all temporaries, including things like: |
| 3940 | // int &&r = 1; |
| 3941 | // int x = ++r; |
| 3942 | // constexpr int k = r; |
| 3943 | // Therefore we use the C++14 rules in C++11 too. |
| 3944 | // |
| 3945 | // Note that temporaries whose lifetimes began while evaluating a |
| 3946 | // variable's constructor are not usable while evaluating the |
| 3947 | // corresponding destructor, not even if they're of const-qualified |
| 3948 | // types. |
| 3949 | if (!(BaseType.isConstQualified() && |
| 3950 | BaseType->isIntegralOrEnumerationType()) && |
| 3951 | !lifetimeStartedInEvaluation(Info, LVal.Base)) { |
| 3952 | if (!IsAccess) |
| 3953 | return CompleteObject(LVal.getLValueBase(), nullptr, BaseType); |
| 3954 | Info.FFDiag(E, diag::note_constexpr_access_static_temporary, 1) << AK; |
| 3955 | Info.Note(MTE->getExprLoc(), diag::note_constexpr_temporary_here); |
| 3956 | return CompleteObject(); |
| 3957 | } |
| 3958 | |
| 3959 | BaseVal = MTE->getOrCreateValue(false); |
| 3960 | assert(BaseVal && "got reference to unevaluated temporary")((BaseVal && "got reference to unevaluated temporary" ) ? static_cast<void> (0) : __assert_fail ("BaseVal && \"got reference to unevaluated temporary\"" , "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 3960, __PRETTY_FUNCTION__)); |
| 3961 | } else { |
| 3962 | if (!IsAccess) |
| 3963 | return CompleteObject(LVal.getLValueBase(), nullptr, BaseType); |
| 3964 | APValue Val; |
| 3965 | LVal.moveInto(Val); |
| 3966 | Info.FFDiag(E, diag::note_constexpr_access_unreadable_object) |
| 3967 | << AK |
| 3968 | << Val.getAsString(Info.Ctx, |
| 3969 | Info.Ctx.getLValueReferenceType(LValType)); |
| 3970 | NoteLValueLocation(Info, LVal.Base); |
| 3971 | return CompleteObject(); |
| 3972 | } |
| 3973 | } else { |
| 3974 | BaseVal = Frame->getTemporary(Base, LVal.Base.getVersion()); |
| 3975 | assert(BaseVal && "missing value for temporary")((BaseVal && "missing value for temporary") ? static_cast <void> (0) : __assert_fail ("BaseVal && \"missing value for temporary\"" , "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 3975, __PRETTY_FUNCTION__)); |
| 3976 | } |
| 3977 | } |
| 3978 | |
| 3979 | // In C++14, we can't safely access any mutable state when we might be |
| 3980 | // evaluating after an unmodeled side effect. |
| 3981 | // |
| 3982 | // FIXME: Not all local state is mutable. Allow local constant subobjects |
| 3983 | // to be read here (but take care with 'mutable' fields). |
| 3984 | if ((Frame && Info.getLangOpts().CPlusPlus14 && |
| 3985 | Info.EvalStatus.HasSideEffects) || |
| 3986 | (isModification(AK) && Depth < Info.SpeculativeEvaluationDepth)) |
| 3987 | return CompleteObject(); |
| 3988 | |
| 3989 | return CompleteObject(LVal.getLValueBase(), BaseVal, BaseType); |
| 3990 | } |
| 3991 | |
| 3992 | /// Perform an lvalue-to-rvalue conversion on the given glvalue. This |
| 3993 | /// can also be used for 'lvalue-to-lvalue' conversions for looking up the |
| 3994 | /// glvalue referred to by an entity of reference type. |
| 3995 | /// |
| 3996 | /// \param Info - Information about the ongoing evaluation. |
| 3997 | /// \param Conv - The expression for which we are performing the conversion. |
| 3998 | /// Used for diagnostics. |
| 3999 | /// \param Type - The type of the glvalue (before stripping cv-qualifiers in the |
| 4000 | /// case of a non-class type). |
| 4001 | /// \param LVal - The glvalue on which we are attempting to perform this action. |
| 4002 | /// \param RVal - The produced value will be placed here. |
| 4003 | /// \param WantObjectRepresentation - If true, we're looking for the object |
| 4004 | /// representation rather than the value, and in particular, |
| 4005 | /// there is no requirement that the result be fully initialized. |
| 4006 | static bool |
| 4007 | handleLValueToRValueConversion(EvalInfo &Info, const Expr *Conv, QualType Type, |
| 4008 | const LValue &LVal, APValue &RVal, |
| 4009 | bool WantObjectRepresentation = false) { |
| 4010 | if (LVal.Designator.Invalid) |
| 4011 | return false; |
| 4012 | |
| 4013 | // Check for special cases where there is no existing APValue to look at. |
| 4014 | const Expr *Base = LVal.Base.dyn_cast<const Expr*>(); |
| 4015 | |
| 4016 | AccessKinds AK = |
| 4017 | WantObjectRepresentation ? AK_ReadObjectRepresentation : AK_Read; |
| 4018 | |
| 4019 | if (Base && !LVal.getLValueCallIndex() && !Type.isVolatileQualified()) { |
| 4020 | if (const CompoundLiteralExpr *CLE = dyn_cast<CompoundLiteralExpr>(Base)) { |
| 4021 | // In C99, a CompoundLiteralExpr is an lvalue, and we defer evaluating the |
| 4022 | // initializer until now for such expressions. Such an expression can't be |
| 4023 | // an ICE in C, so this only matters for fold. |
| 4024 | if (Type.isVolatileQualified()) { |
| 4025 | Info.FFDiag(Conv); |
| 4026 | return false; |
| 4027 | } |
| 4028 | APValue Lit; |
| 4029 | if (!Evaluate(Lit, Info, CLE->getInitializer())) |
| 4030 | return false; |
| 4031 | CompleteObject LitObj(LVal.Base, &Lit, Base->getType()); |
| 4032 | return extractSubobject(Info, Conv, LitObj, LVal.Designator, RVal, AK); |
| 4033 | } else if (isa<StringLiteral>(Base) || isa<PredefinedExpr>(Base)) { |
| 4034 | // Special-case character extraction so we don't have to construct an |
| 4035 | // APValue for the whole string. |
| 4036 | assert(LVal.Designator.Entries.size() <= 1 &&((LVal.Designator.Entries.size() <= 1 && "Can only read characters from string literals" ) ? static_cast<void> (0) : __assert_fail ("LVal.Designator.Entries.size() <= 1 && \"Can only read characters from string literals\"" , "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 4037, __PRETTY_FUNCTION__)) |
| 4037 | "Can only read characters from string literals")((LVal.Designator.Entries.size() <= 1 && "Can only read characters from string literals" ) ? static_cast<void> (0) : __assert_fail ("LVal.Designator.Entries.size() <= 1 && \"Can only read characters from string literals\"" , "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 4037, __PRETTY_FUNCTION__)); |
| 4038 | if (LVal.Designator.Entries.empty()) { |
| 4039 | // Fail for now for LValue to RValue conversion of an array. |
| 4040 | // (This shouldn't show up in C/C++, but it could be triggered by a |
| 4041 | // weird EvaluateAsRValue call from a tool.) |
| 4042 | Info.FFDiag(Conv); |
| 4043 | return false; |
| 4044 | } |
| 4045 | if (LVal.Designator.isOnePastTheEnd()) { |
| 4046 | if (Info.getLangOpts().CPlusPlus11) |
| 4047 | Info.FFDiag(Conv, diag::note_constexpr_access_past_end) << AK; |
| 4048 | else |
| 4049 | Info.FFDiag(Conv); |
| 4050 | return false; |
| 4051 | } |
| 4052 | uint64_t CharIndex = LVal.Designator.Entries[0].getAsArrayIndex(); |
| 4053 | RVal = APValue(extractStringLiteralCharacter(Info, Base, CharIndex)); |
| 4054 | return true; |
| 4055 | } |
| 4056 | } |
| 4057 | |
| 4058 | CompleteObject Obj = findCompleteObject(Info, Conv, AK, LVal, Type); |
| 4059 | return Obj && extractSubobject(Info, Conv, Obj, LVal.Designator, RVal, AK); |
| 4060 | } |
| 4061 | |
| 4062 | /// Perform an assignment of Val to LVal. Takes ownership of Val. |
| 4063 | static bool handleAssignment(EvalInfo &Info, const Expr *E, const LValue &LVal, |
| 4064 | QualType LValType, APValue &Val) { |
| 4065 | if (LVal.Designator.Invalid) |
| 4066 | return false; |
| 4067 | |
| 4068 | if (!Info.getLangOpts().CPlusPlus14) { |
| 4069 | Info.FFDiag(E); |
| 4070 | return false; |
| 4071 | } |
| 4072 | |
| 4073 | CompleteObject Obj = findCompleteObject(Info, E, AK_Assign, LVal, LValType); |
| 4074 | return Obj && modifySubobject(Info, E, Obj, LVal.Designator, Val); |
| 4075 | } |
| 4076 | |
| 4077 | namespace { |
| 4078 | struct CompoundAssignSubobjectHandler { |
| 4079 | EvalInfo &Info; |
| 4080 | const Expr *E; |
| 4081 | QualType PromotedLHSType; |
| 4082 | BinaryOperatorKind Opcode; |
| 4083 | const APValue &RHS; |
| 4084 | |
| 4085 | static const AccessKinds AccessKind = AK_Assign; |
| 4086 | |
| 4087 | typedef bool result_type; |
| 4088 | |
| 4089 | bool checkConst(QualType QT) { |
| 4090 | // Assigning to a const object has undefined behavior. |
| 4091 | if (QT.isConstQualified()) { |
| 4092 | Info.FFDiag(E, diag::note_constexpr_modify_const_type) << QT; |
| 4093 | return false; |
| 4094 | } |
| 4095 | return true; |
| 4096 | } |
| 4097 | |
| 4098 | bool failed() { return false; } |
| 4099 | bool found(APValue &Subobj, QualType SubobjType) { |
| 4100 | switch (Subobj.getKind()) { |
| 4101 | case APValue::Int: |
| 4102 | return found(Subobj.getInt(), SubobjType); |
| 4103 | case APValue::Float: |
| 4104 | return found(Subobj.getFloat(), SubobjType); |
| 4105 | case APValue::ComplexInt: |
| 4106 | case APValue::ComplexFloat: |
| 4107 | // FIXME: Implement complex compound assignment. |
| 4108 | Info.FFDiag(E); |
| 4109 | return false; |
| 4110 | case APValue::LValue: |
| 4111 | return foundPointer(Subobj, SubobjType); |
| 4112 | case APValue::Vector: |
| 4113 | return foundVector(Subobj, SubobjType); |
| 4114 | default: |
| 4115 | // FIXME: can this happen? |
| 4116 | Info.FFDiag(E); |
| 4117 | return false; |
| 4118 | } |
| 4119 | } |
| 4120 | |
| 4121 | bool foundVector(APValue &Value, QualType SubobjType) { |
| 4122 | if (!checkConst(SubobjType)) |
| 4123 | return false; |
| 4124 | |
| 4125 | if (!SubobjType->isVectorType()) { |
| 4126 | Info.FFDiag(E); |
| 4127 | return false; |
| 4128 | } |
| 4129 | return handleVectorVectorBinOp(Info, E, Opcode, Value, RHS); |
| 4130 | } |
| 4131 | |
| 4132 | bool found(APSInt &Value, QualType SubobjType) { |
| 4133 | if (!checkConst(SubobjType)) |
| 4134 | return false; |
| 4135 | |
| 4136 | if (!SubobjType->isIntegerType()) { |
| 4137 | // We don't support compound assignment on integer-cast-to-pointer |
| 4138 | // values. |
| 4139 | Info.FFDiag(E); |
| 4140 | return false; |
| 4141 | } |
| 4142 | |
| 4143 | if (RHS.isInt()) { |
| 4144 | APSInt LHS = |
| 4145 | HandleIntToIntCast(Info, E, PromotedLHSType, SubobjType, Value); |
| 4146 | if (!handleIntIntBinOp(Info, E, LHS, Opcode, RHS.getInt(), LHS)) |
| 4147 | return false; |
| 4148 | Value = HandleIntToIntCast(Info, E, SubobjType, PromotedLHSType, LHS); |
| 4149 | return true; |
| 4150 | } else if (RHS.isFloat()) { |
| 4151 | APFloat FValue(0.0); |
| 4152 | return HandleIntToFloatCast(Info, E, SubobjType, Value, PromotedLHSType, |
| 4153 | FValue) && |
| 4154 | handleFloatFloatBinOp(Info, E, FValue, Opcode, RHS.getFloat()) && |
| 4155 | HandleFloatToIntCast(Info, E, PromotedLHSType, FValue, SubobjType, |
| 4156 | Value); |
| 4157 | } |
| 4158 | |
| 4159 | Info.FFDiag(E); |
| 4160 | return false; |
| 4161 | } |
| 4162 | bool found(APFloat &Value, QualType SubobjType) { |
| 4163 | return checkConst(SubobjType) && |
| 4164 | HandleFloatToFloatCast(Info, E, SubobjType, PromotedLHSType, |
| 4165 | Value) && |
| 4166 | handleFloatFloatBinOp(Info, E, Value, Opcode, RHS.getFloat()) && |
| 4167 | HandleFloatToFloatCast(Info, E, PromotedLHSType, SubobjType, Value); |
| 4168 | } |
| 4169 | bool foundPointer(APValue &Subobj, QualType SubobjType) { |
| 4170 | if (!checkConst(SubobjType)) |
| 4171 | return false; |
| 4172 | |
| 4173 | QualType PointeeType; |
| 4174 | if (const PointerType *PT = SubobjType->getAs<PointerType>()) |
| 4175 | PointeeType = PT->getPointeeType(); |
| 4176 | |
| 4177 | if (PointeeType.isNull() || !RHS.isInt() || |
| 4178 | (Opcode != BO_Add && Opcode != BO_Sub)) { |
| 4179 | Info.FFDiag(E); |
| 4180 | return false; |
| 4181 | } |
| 4182 | |
| 4183 | APSInt Offset = RHS.getInt(); |
| 4184 | if (Opcode == BO_Sub) |
| 4185 | negateAsSigned(Offset); |
| 4186 | |
| 4187 | LValue LVal; |
| 4188 | LVal.setFrom(Info.Ctx, Subobj); |
| 4189 | if (!HandleLValueArrayAdjustment(Info, E, LVal, PointeeType, Offset)) |
| 4190 | return false; |
| 4191 | LVal.moveInto(Subobj); |
| 4192 | return true; |
| 4193 | } |
| 4194 | }; |
| 4195 | } // end anonymous namespace |
| 4196 | |
| 4197 | const AccessKinds CompoundAssignSubobjectHandler::AccessKind; |
| 4198 | |
| 4199 | /// Perform a compound assignment of LVal <op>= RVal. |
| 4200 | static bool handleCompoundAssignment( |
| 4201 | EvalInfo &Info, const Expr *E, |
| 4202 | const LValue &LVal, QualType LValType, QualType PromotedLValType, |
| 4203 | BinaryOperatorKind Opcode, const APValue &RVal) { |
| 4204 | if (LVal.Designator.Invalid) |
| 4205 | return false; |
| 4206 | |
| 4207 | if (!Info.getLangOpts().CPlusPlus14) { |
| 4208 | Info.FFDiag(E); |
| 4209 | return false; |
| 4210 | } |
| 4211 | |
| 4212 | CompleteObject Obj = findCompleteObject(Info, E, AK_Assign, LVal, LValType); |
| 4213 | CompoundAssignSubobjectHandler Handler = { Info, E, PromotedLValType, Opcode, |
| 4214 | RVal }; |
| 4215 | return Obj && findSubobject(Info, E, Obj, LVal.Designator, Handler); |
| 4216 | } |
| 4217 | |
| 4218 | namespace { |
| 4219 | struct IncDecSubobjectHandler { |
| 4220 | EvalInfo &Info; |
| 4221 | const UnaryOperator *E; |
| 4222 | AccessKinds AccessKind; |
| 4223 | APValue *Old; |
| 4224 | |
| 4225 | typedef bool result_type; |
| 4226 | |
| 4227 | bool checkConst(QualType QT) { |
| 4228 | // Assigning to a const object has undefined behavior. |
| 4229 | if (QT.isConstQualified()) { |
| 4230 | Info.FFDiag(E, diag::note_constexpr_modify_const_type) << QT; |
| 4231 | return false; |
| 4232 | } |
| 4233 | return true; |
| 4234 | } |
| 4235 | |
| 4236 | bool failed() { return false; } |
| 4237 | bool found(APValue &Subobj, QualType SubobjType) { |
| 4238 | // Stash the old value. Also clear Old, so we don't clobber it later |
| 4239 | // if we're post-incrementing a complex. |
| 4240 | if (Old) { |
| 4241 | *Old = Subobj; |
| 4242 | Old = nullptr; |
| 4243 | } |
| 4244 | |
| 4245 | switch (Subobj.getKind()) { |
| 4246 | case APValue::Int: |
| 4247 | return found(Subobj.getInt(), SubobjType); |
| 4248 | case APValue::Float: |
| 4249 | return found(Subobj.getFloat(), SubobjType); |
| 4250 | case APValue::ComplexInt: |
| 4251 | return found(Subobj.getComplexIntReal(), |
| 4252 | SubobjType->castAs<ComplexType>()->getElementType() |
| 4253 | .withCVRQualifiers(SubobjType.getCVRQualifiers())); |
| 4254 | case APValue::ComplexFloat: |
| 4255 | return found(Subobj.getComplexFloatReal(), |
| 4256 | SubobjType->castAs<ComplexType>()->getElementType() |
| 4257 | .withCVRQualifiers(SubobjType.getCVRQualifiers())); |
| 4258 | case APValue::LValue: |
| 4259 | return foundPointer(Subobj, SubobjType); |
| 4260 | default: |
| 4261 | // FIXME: can this happen? |
| 4262 | Info.FFDiag(E); |
| 4263 | return false; |
| 4264 | } |
| 4265 | } |
| 4266 | bool found(APSInt &Value, QualType SubobjType) { |
| 4267 | if (!checkConst(SubobjType)) |
| 4268 | return false; |
| 4269 | |
| 4270 | if (!SubobjType->isIntegerType()) { |
| 4271 | // We don't support increment / decrement on integer-cast-to-pointer |
| 4272 | // values. |
| 4273 | Info.FFDiag(E); |
| 4274 | return false; |
| 4275 | } |
| 4276 | |
| 4277 | if (Old) *Old = APValue(Value); |
| 4278 | |
| 4279 | // bool arithmetic promotes to int, and the conversion back to bool |
| 4280 | // doesn't reduce mod 2^n, so special-case it. |
| 4281 | if (SubobjType->isBooleanType()) { |
| 4282 | if (AccessKind == AK_Increment) |
| 4283 | Value = 1; |
| 4284 | else |
| 4285 | Value = !Value; |
| 4286 | return true; |
| 4287 | } |
| 4288 | |
| 4289 | bool WasNegative = Value.isNegative(); |
| 4290 | if (AccessKind == AK_Increment) { |
| 4291 | ++Value; |
| 4292 | |
| 4293 | if (!WasNegative && Value.isNegative() && E->canOverflow()) { |
| 4294 | APSInt ActualValue(Value, /*IsUnsigned*/true); |
| 4295 | return HandleOverflow(Info, E, ActualValue, SubobjType); |
| 4296 | } |
| 4297 | } else { |
| 4298 | --Value; |
| 4299 | |
| 4300 | if (WasNegative && !Value.isNegative() && E->canOverflow()) { |
| 4301 | unsigned BitWidth = Value.getBitWidth(); |
| 4302 | APSInt ActualValue(Value.sext(BitWidth + 1), /*IsUnsigned*/false); |
| 4303 | ActualValue.setBit(BitWidth); |
| 4304 | return HandleOverflow(Info, E, ActualValue, SubobjType); |
| 4305 | } |
| 4306 | } |
| 4307 | return true; |
| 4308 | } |
| 4309 | bool found(APFloat &Value, QualType SubobjType) { |
| 4310 | if (!checkConst(SubobjType)) |
| 4311 | return false; |
| 4312 | |
| 4313 | if (Old) *Old = APValue(Value); |
| 4314 | |
| 4315 | APFloat One(Value.getSemantics(), 1); |
| 4316 | if (AccessKind == AK_Increment) |
| 4317 | Value.add(One, APFloat::rmNearestTiesToEven); |
| 4318 | else |
| 4319 | Value.subtract(One, APFloat::rmNearestTiesToEven); |
| 4320 | return true; |
| 4321 | } |
| 4322 | bool foundPointer(APValue &Subobj, QualType SubobjType) { |
| 4323 | if (!checkConst(SubobjType)) |
| 4324 | return false; |
| 4325 | |
| 4326 | QualType PointeeType; |
| 4327 | if (const PointerType *PT = SubobjType->getAs<PointerType>()) |
| 4328 | PointeeType = PT->getPointeeType(); |
| 4329 | else { |
| 4330 | Info.FFDiag(E); |
| 4331 | return false; |
| 4332 | } |
| 4333 | |
| 4334 | LValue LVal; |
| 4335 | LVal.setFrom(Info.Ctx, Subobj); |
| 4336 | if (!HandleLValueArrayAdjustment(Info, E, LVal, PointeeType, |
| 4337 | AccessKind == AK_Increment ? 1 : -1)) |
| 4338 | return false; |
| 4339 | LVal.moveInto(Subobj); |
| 4340 | return true; |
| 4341 | } |
| 4342 | }; |
| 4343 | } // end anonymous namespace |
| 4344 | |
| 4345 | /// Perform an increment or decrement on LVal. |
| 4346 | static bool handleIncDec(EvalInfo &Info, const Expr *E, const LValue &LVal, |
| 4347 | QualType LValType, bool IsIncrement, APValue *Old) { |
| 4348 | if (LVal.Designator.Invalid) |
| 4349 | return false; |
| 4350 | |
| 4351 | if (!Info.getLangOpts().CPlusPlus14) { |
| 4352 | Info.FFDiag(E); |
| 4353 | return false; |
| 4354 | } |
| 4355 | |
| 4356 | AccessKinds AK = IsIncrement ? AK_Increment : AK_Decrement; |
| 4357 | CompleteObject Obj = findCompleteObject(Info, E, AK, LVal, LValType); |
| 4358 | IncDecSubobjectHandler Handler = {Info, cast<UnaryOperator>(E), AK, Old}; |
| 4359 | return Obj && findSubobject(Info, E, Obj, LVal.Designator, Handler); |
| 4360 | } |
| 4361 | |
| 4362 | /// Build an lvalue for the object argument of a member function call. |
| 4363 | static bool EvaluateObjectArgument(EvalInfo &Info, const Expr *Object, |
| 4364 | LValue &This) { |
| 4365 | if (Object->getType()->isPointerType() && Object->isRValue()) |
| 4366 | return EvaluatePointer(Object, This, Info); |
| 4367 | |
| 4368 | if (Object->isGLValue()) |
| 4369 | return EvaluateLValue(Object, This, Info); |
| 4370 | |
| 4371 | if (Object->getType()->isLiteralType(Info.Ctx)) |
| 4372 | return EvaluateTemporary(Object, This, Info); |
| 4373 | |
| 4374 | Info.FFDiag(Object, diag::note_constexpr_nonliteral) << Object->getType(); |
| 4375 | return false; |
| 4376 | } |
| 4377 | |
| 4378 | /// HandleMemberPointerAccess - Evaluate a member access operation and build an |
| 4379 | /// lvalue referring to the result. |
| 4380 | /// |
| 4381 | /// \param Info - Information about the ongoing evaluation. |
| 4382 | /// \param LV - An lvalue referring to the base of the member pointer. |
| 4383 | /// \param RHS - The member pointer expression. |
| 4384 | /// \param IncludeMember - Specifies whether the member itself is included in |
| 4385 | /// the resulting LValue subobject designator. This is not possible when |
| 4386 | /// creating a bound member function. |
| 4387 | /// \return The field or method declaration to which the member pointer refers, |
| 4388 | /// or 0 if evaluation fails. |
| 4389 | static const ValueDecl *HandleMemberPointerAccess(EvalInfo &Info, |
| 4390 | QualType LVType, |
| 4391 | LValue &LV, |
| 4392 | const Expr *RHS, |
| 4393 | bool IncludeMember = true) { |
| 4394 | MemberPtr MemPtr; |
| 4395 | if (!EvaluateMemberPointer(RHS, MemPtr, Info)) |
| 4396 | return nullptr; |
| 4397 | |
| 4398 | // C++11 [expr.mptr.oper]p6: If the second operand is the null pointer to |
| 4399 | // member value, the behavior is undefined. |
| 4400 | if (!MemPtr.getDecl()) { |
| 4401 | // FIXME: Specific diagnostic. |
| 4402 | Info.FFDiag(RHS); |
| 4403 | return nullptr; |
| 4404 | } |
| 4405 | |
| 4406 | if (MemPtr.isDerivedMember()) { |
| 4407 | // This is a member of some derived class. Truncate LV appropriately. |
| 4408 | // The end of the derived-to-base path for the base object must match the |
| 4409 | // derived-to-base path for the member pointer. |
| 4410 | if (LV.Designator.MostDerivedPathLength + MemPtr.Path.size() > |
| 4411 | LV.Designator.Entries.size()) { |
| 4412 | Info.FFDiag(RHS); |
| 4413 | return nullptr; |
| 4414 | } |
| 4415 | unsigned PathLengthToMember = |
| 4416 | LV.Designator.Entries.size() - MemPtr.Path.size(); |
| 4417 | for (unsigned I = 0, N = MemPtr.Path.size(); I != N; ++I) { |
| 4418 | const CXXRecordDecl *LVDecl = getAsBaseClass( |
| 4419 | LV.Designator.Entries[PathLengthToMember + I]); |
| 4420 | const CXXRecordDecl *MPDecl = MemPtr.Path[I]; |
| 4421 | if (LVDecl->getCanonicalDecl() != MPDecl->getCanonicalDecl()) { |
| 4422 | Info.FFDiag(RHS); |
| 4423 | return nullptr; |
| 4424 | } |
| 4425 | } |
| 4426 | |
| 4427 | // Truncate the lvalue to the appropriate derived class. |
| 4428 | if (!CastToDerivedClass(Info, RHS, LV, MemPtr.getContainingRecord(), |
| 4429 | PathLengthToMember)) |
| 4430 | return nullptr; |
| 4431 | } else if (!MemPtr.Path.empty()) { |
| 4432 | // Extend the LValue path with the member pointer's path. |
| 4433 | LV.Designator.Entries.reserve(LV.Designator.Entries.size() + |
| 4434 | MemPtr.Path.size() + IncludeMember); |
| 4435 | |
| 4436 | // Walk down to the appropriate base class. |
| 4437 | if (const PointerType *PT = LVType->getAs<PointerType>()) |
| 4438 | LVType = PT->getPointeeType(); |
| 4439 | const CXXRecordDecl *RD = LVType->getAsCXXRecordDecl(); |
| 4440 | assert(RD && "member pointer access on non-class-type expression")((RD && "member pointer access on non-class-type expression" ) ? static_cast<void> (0) : __assert_fail ("RD && \"member pointer access on non-class-type expression\"" , "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 4440, __PRETTY_FUNCTION__)); |
| 4441 | // The first class in the path is that of the lvalue. |
| 4442 | for (unsigned I = 1, N = MemPtr.Path.size(); I != N; ++I) { |
| 4443 | const CXXRecordDecl *Base = MemPtr.Path[N - I - 1]; |
| 4444 | if (!HandleLValueDirectBase(Info, RHS, LV, RD, Base)) |
| 4445 | return nullptr; |
| 4446 | RD = Base; |
| 4447 | } |
| 4448 | // Finally cast to the class containing the member. |
| 4449 | if (!HandleLValueDirectBase(Info, RHS, LV, RD, |
| 4450 | MemPtr.getContainingRecord())) |
| 4451 | return nullptr; |
| 4452 | } |
| 4453 | |
| 4454 | // Add the member. Note that we cannot build bound member functions here. |
| 4455 | if (IncludeMember) { |
| 4456 | if (const FieldDecl *FD = dyn_cast<FieldDecl>(MemPtr.getDecl())) { |
| 4457 | if (!HandleLValueMember(Info, RHS, LV, FD)) |
| 4458 | return nullptr; |
| 4459 | } else if (const IndirectFieldDecl *IFD = |
| 4460 | dyn_cast<IndirectFieldDecl>(MemPtr.getDecl())) { |
| 4461 | if (!HandleLValueIndirectMember(Info, RHS, LV, IFD)) |
| 4462 | return nullptr; |
| 4463 | } else { |
| 4464 | llvm_unreachable("can't construct reference to bound member function")::llvm::llvm_unreachable_internal("can't construct reference to bound member function" , "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 4464); |
| 4465 | } |
| 4466 | } |
| 4467 | |
| 4468 | return MemPtr.getDecl(); |
| 4469 | } |
| 4470 | |
| 4471 | static const ValueDecl *HandleMemberPointerAccess(EvalInfo &Info, |
| 4472 | const BinaryOperator *BO, |
| 4473 | LValue &LV, |
| 4474 | bool IncludeMember = true) { |
| 4475 | assert(BO->getOpcode() == BO_PtrMemD || BO->getOpcode() == BO_PtrMemI)((BO->getOpcode() == BO_PtrMemD || BO->getOpcode() == BO_PtrMemI ) ? static_cast<void> (0) : __assert_fail ("BO->getOpcode() == BO_PtrMemD || BO->getOpcode() == BO_PtrMemI" , "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 4475, __PRETTY_FUNCTION__)); |
| 4476 | |
| 4477 | if (!EvaluateObjectArgument(Info, BO->getLHS(), LV)) { |
| 4478 | if (Info.noteFailure()) { |
| 4479 | MemberPtr MemPtr; |
| 4480 | EvaluateMemberPointer(BO->getRHS(), MemPtr, Info); |
| 4481 | } |
| 4482 | return nullptr; |
| 4483 | } |
| 4484 | |
| 4485 | return HandleMemberPointerAccess(Info, BO->getLHS()->getType(), LV, |
| 4486 | BO->getRHS(), IncludeMember); |
| 4487 | } |
| 4488 | |
| 4489 | /// HandleBaseToDerivedCast - Apply the given base-to-derived cast operation on |
| 4490 | /// the provided lvalue, which currently refers to the base object. |
| 4491 | static bool HandleBaseToDerivedCast(EvalInfo &Info, const CastExpr *E, |
| 4492 | LValue &Result) { |
| 4493 | SubobjectDesignator &D = Result.Designator; |
| 4494 | if (D.Invalid || !Result.checkNullPointer(Info, E, CSK_Derived)) |
| 4495 | return false; |
| 4496 | |
| 4497 | QualType TargetQT = E->getType(); |
| 4498 | if (const PointerType *PT = TargetQT->getAs<PointerType>()) |
| 4499 | TargetQT = PT->getPointeeType(); |
| 4500 | |
| 4501 | // Check this cast lands within the final derived-to-base subobject path. |
| 4502 | if (D.MostDerivedPathLength + E->path_size() > D.Entries.size()) { |
| 4503 | Info.CCEDiag(E, diag::note_constexpr_invalid_downcast) |
| 4504 | << D.MostDerivedType << TargetQT; |
| 4505 | return false; |
| 4506 | } |
| 4507 | |
| 4508 | // Check the type of the final cast. We don't need to check the path, |
| 4509 | // since a cast can only be formed if the path is unique. |
| 4510 | unsigned NewEntriesSize = D.Entries.size() - E->path_size(); |
| 4511 | const CXXRecordDecl *TargetType = TargetQT->getAsCXXRecordDecl(); |
| 4512 | const CXXRecordDecl *FinalType; |
| 4513 | if (NewEntriesSize == D.MostDerivedPathLength) |
| 4514 | FinalType = D.MostDerivedType->getAsCXXRecordDecl(); |
| 4515 | else |
| 4516 | FinalType = getAsBaseClass(D.Entries[NewEntriesSize - 1]); |
| 4517 | if (FinalType->getCanonicalDecl() != TargetType->getCanonicalDecl()) { |
| 4518 | Info.CCEDiag(E, diag::note_constexpr_invalid_downcast) |
| 4519 | << D.MostDerivedType << TargetQT; |
| 4520 | return false; |
| 4521 | } |
| 4522 | |
| 4523 | // Truncate the lvalue to the appropriate derived class. |
| 4524 | return CastToDerivedClass(Info, E, Result, TargetType, NewEntriesSize); |
| 4525 | } |
| 4526 | |
| 4527 | /// Get the value to use for a default-initialized object of type T. |
| 4528 | /// Return false if it encounters something invalid. |
| 4529 | static bool getDefaultInitValue(QualType T, APValue &Result) { |
| 4530 | bool Success = true; |
| 4531 | if (auto *RD = T->getAsCXXRecordDecl()) { |
| 4532 | if (RD->isInvalidDecl()) { |
| 4533 | Result = APValue(); |
| 4534 | return false; |
| 4535 | } |
| 4536 | if (RD->isUnion()) { |
| 4537 | Result = APValue((const FieldDecl *)nullptr); |
| 4538 | return true; |
| 4539 | } |
| 4540 | Result = APValue(APValue::UninitStruct(), RD->getNumBases(), |
| 4541 | std::distance(RD->field_begin(), RD->field_end())); |
| 4542 | |
| 4543 | unsigned Index = 0; |
| 4544 | for (CXXRecordDecl::base_class_const_iterator I = RD->bases_begin(), |
| 4545 | End = RD->bases_end(); |
| 4546 | I != End; ++I, ++Index) |
| 4547 | Success &= getDefaultInitValue(I->getType(), Result.getStructBase(Index)); |
| 4548 | |
| 4549 | for (const auto *I : RD->fields()) { |
| 4550 | if (I->isUnnamedBitfield()) |
| 4551 | continue; |
| 4552 | Success &= getDefaultInitValue(I->getType(), |
| 4553 | Result.getStructField(I->getFieldIndex())); |
| 4554 | } |
| 4555 | return Success; |
| 4556 | } |
| 4557 | |
| 4558 | if (auto *AT = |
| 4559 | dyn_cast_or_null<ConstantArrayType>(T->getAsArrayTypeUnsafe())) { |
| 4560 | Result = APValue(APValue::UninitArray(), 0, AT->getSize().getZExtValue()); |
| 4561 | if (Result.hasArrayFiller()) |
| 4562 | Success &= |
| 4563 | getDefaultInitValue(AT->getElementType(), Result.getArrayFiller()); |
| 4564 | |
| 4565 | return Success; |
| 4566 | } |
| 4567 | |
| 4568 | Result = APValue::IndeterminateValue(); |
| 4569 | return true; |
| 4570 | } |
| 4571 | |
| 4572 | namespace { |
| 4573 | enum EvalStmtResult { |
| 4574 | /// Evaluation failed. |
| 4575 | ESR_Failed, |
| 4576 | /// Hit a 'return' statement. |
| 4577 | ESR_Returned, |
| 4578 | /// Evaluation succeeded. |
| 4579 | ESR_Succeeded, |
| 4580 | /// Hit a 'continue' statement. |
| 4581 | ESR_Continue, |
| 4582 | /// Hit a 'break' statement. |
| 4583 | ESR_Break, |
| 4584 | /// Still scanning for 'case' or 'default' statement. |
| 4585 | ESR_CaseNotFound |
| 4586 | }; |
| 4587 | } |
| 4588 | |
| 4589 | static bool EvaluateVarDecl(EvalInfo &Info, const VarDecl *VD) { |
| 4590 | // We don't need to evaluate the initializer for a static local. |
| 4591 | if (!VD->hasLocalStorage()) |
| 4592 | return true; |
| 4593 | |
| 4594 | LValue Result; |
| 4595 | APValue &Val = |
| 4596 | Info.CurrentCall->createTemporary(VD, VD->getType(), true, Result); |
| 4597 | |
| 4598 | const Expr *InitE = VD->getInit(); |
| 4599 | if (!InitE) |
| 4600 | return getDefaultInitValue(VD->getType(), Val); |
| 4601 | |
| 4602 | if (InitE->isValueDependent()) |
| 4603 | return false; |
| 4604 | |
| 4605 | if (!EvaluateInPlace(Val, Info, Result, InitE)) { |
| 4606 | // Wipe out any partially-computed value, to allow tracking that this |
| 4607 | // evaluation failed. |
| 4608 | Val = APValue(); |
| 4609 | return false; |
| 4610 | } |
| 4611 | |
| 4612 | return true; |
| 4613 | } |
| 4614 | |
| 4615 | static bool EvaluateDecl(EvalInfo &Info, const Decl *D) { |
| 4616 | bool OK = true; |
| 4617 | |
| 4618 | if (const VarDecl *VD = dyn_cast<VarDecl>(D)) |
| 4619 | OK &= EvaluateVarDecl(Info, VD); |
| 4620 | |
| 4621 | if (const DecompositionDecl *DD = dyn_cast<DecompositionDecl>(D)) |
| 4622 | for (auto *BD : DD->bindings()) |
| 4623 | if (auto *VD = BD->getHoldingVar()) |
| 4624 | OK &= EvaluateDecl(Info, VD); |
| 4625 | |
| 4626 | return OK; |
| 4627 | } |
| 4628 | |
| 4629 | |
| 4630 | /// Evaluate a condition (either a variable declaration or an expression). |
| 4631 | static bool EvaluateCond(EvalInfo &Info, const VarDecl *CondDecl, |
| 4632 | const Expr *Cond, bool &Result) { |
| 4633 | FullExpressionRAII Scope(Info); |
| 4634 | if (CondDecl && !EvaluateDecl(Info, CondDecl)) |
| 4635 | return false; |
| 4636 | if (!EvaluateAsBooleanCondition(Cond, Result, Info)) |
| 4637 | return false; |
| 4638 | return Scope.destroy(); |
| 4639 | } |
| 4640 | |
| 4641 | namespace { |
| 4642 | /// A location where the result (returned value) of evaluating a |
| 4643 | /// statement should be stored. |
| 4644 | struct StmtResult { |
| 4645 | /// The APValue that should be filled in with the returned value. |
| 4646 | APValue &Value; |
| 4647 | /// The location containing the result, if any (used to support RVO). |
| 4648 | const LValue *Slot; |
| 4649 | }; |
| 4650 | |
| 4651 | struct TempVersionRAII { |
| 4652 | CallStackFrame &Frame; |
| 4653 | |
| 4654 | TempVersionRAII(CallStackFrame &Frame) : Frame(Frame) { |
| 4655 | Frame.pushTempVersion(); |
| 4656 | } |
| 4657 | |
| 4658 | ~TempVersionRAII() { |
| 4659 | Frame.popTempVersion(); |
| 4660 | } |
| 4661 | }; |
| 4662 | |
| 4663 | } |
| 4664 | |
| 4665 | static EvalStmtResult EvaluateStmt(StmtResult &Result, EvalInfo &Info, |
| 4666 | const Stmt *S, |
| 4667 | const SwitchCase *SC = nullptr); |
| 4668 | |
| 4669 | /// Evaluate the body of a loop, and translate the result as appropriate. |
| 4670 | static EvalStmtResult EvaluateLoopBody(StmtResult &Result, EvalInfo &Info, |
| 4671 | const Stmt *Body, |
| 4672 | const SwitchCase *Case = nullptr) { |
| 4673 | BlockScopeRAII Scope(Info); |
| 4674 | |
| 4675 | EvalStmtResult ESR = EvaluateStmt(Result, Info, Body, Case); |
| 4676 | if (ESR != ESR_Failed && ESR != ESR_CaseNotFound && !Scope.destroy()) |
| 4677 | ESR = ESR_Failed; |
| 4678 | |
| 4679 | switch (ESR) { |
| 4680 | case ESR_Break: |
| 4681 | return ESR_Succeeded; |
| 4682 | case ESR_Succeeded: |
| 4683 | case ESR_Continue: |
| 4684 | return ESR_Continue; |
| 4685 | case ESR_Failed: |
| 4686 | case ESR_Returned: |
| 4687 | case ESR_CaseNotFound: |
| 4688 | return ESR; |
| 4689 | } |
| 4690 | llvm_unreachable("Invalid EvalStmtResult!")::llvm::llvm_unreachable_internal("Invalid EvalStmtResult!", "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 4690); |
| 4691 | } |
| 4692 | |
| 4693 | /// Evaluate a switch statement. |
| 4694 | static EvalStmtResult EvaluateSwitch(StmtResult &Result, EvalInfo &Info, |
| 4695 | const SwitchStmt *SS) { |
| 4696 | BlockScopeRAII Scope(Info); |
| 4697 | |
| 4698 | // Evaluate the switch condition. |
| 4699 | APSInt Value; |
| 4700 | { |
| 4701 | if (const Stmt *Init = SS->getInit()) { |
| 4702 | EvalStmtResult ESR = EvaluateStmt(Result, Info, Init); |
| 4703 | if (ESR != ESR_Succeeded) { |
| 4704 | if (ESR != ESR_Failed && !Scope.destroy()) |
| 4705 | ESR = ESR_Failed; |
| 4706 | return ESR; |
| 4707 | } |
| 4708 | } |
| 4709 | |
| 4710 | FullExpressionRAII CondScope(Info); |
| 4711 | if (SS->getConditionVariable() && |
| 4712 | !EvaluateDecl(Info, SS->getConditionVariable())) |
| 4713 | return ESR_Failed; |
| 4714 | if (!EvaluateInteger(SS->getCond(), Value, Info)) |
| 4715 | return ESR_Failed; |
| 4716 | if (!CondScope.destroy()) |
| 4717 | return ESR_Failed; |
| 4718 | } |
| 4719 | |
| 4720 | // Find the switch case corresponding to the value of the condition. |
| 4721 | // FIXME: Cache this lookup. |
| 4722 | const SwitchCase *Found = nullptr; |
| 4723 | for (const SwitchCase *SC = SS->getSwitchCaseList(); SC; |
| 4724 | SC = SC->getNextSwitchCase()) { |
| 4725 | if (isa<DefaultStmt>(SC)) { |
| 4726 | Found = SC; |
| 4727 | continue; |
| 4728 | } |
| 4729 | |
| 4730 | const CaseStmt *CS = cast<CaseStmt>(SC); |
| 4731 | APSInt LHS = CS->getLHS()->EvaluateKnownConstInt(Info.Ctx); |
| 4732 | APSInt RHS = CS->getRHS() ? CS->getRHS()->EvaluateKnownConstInt(Info.Ctx) |
| 4733 | : LHS; |
| 4734 | if (LHS <= Value && Value <= RHS) { |
| 4735 | Found = SC; |
| 4736 | break; |
| 4737 | } |
| 4738 | } |
| 4739 | |
| 4740 | if (!Found) |
| 4741 | return Scope.destroy() ? ESR_Succeeded : ESR_Failed; |
| 4742 | |
| 4743 | // Search the switch body for the switch case and evaluate it from there. |
| 4744 | EvalStmtResult ESR = EvaluateStmt(Result, Info, SS->getBody(), Found); |
| 4745 | if (ESR != ESR_Failed && ESR != ESR_CaseNotFound && !Scope.destroy()) |
| 4746 | return ESR_Failed; |
| 4747 | |
| 4748 | switch (ESR) { |
| 4749 | case ESR_Break: |
| 4750 | return ESR_Succeeded; |
| 4751 | case ESR_Succeeded: |
| 4752 | case ESR_Continue: |
| 4753 | case ESR_Failed: |
| 4754 | case ESR_Returned: |
| 4755 | return ESR; |
| 4756 | case ESR_CaseNotFound: |
| 4757 | // This can only happen if the switch case is nested within a statement |
| 4758 | // expression. We have no intention of supporting that. |
| 4759 | Info.FFDiag(Found->getBeginLoc(), |
| 4760 | diag::note_constexpr_stmt_expr_unsupported); |
| 4761 | return ESR_Failed; |
| 4762 | } |
| 4763 | llvm_unreachable("Invalid EvalStmtResult!")::llvm::llvm_unreachable_internal("Invalid EvalStmtResult!", "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 4763); |
| 4764 | } |
| 4765 | |
| 4766 | // Evaluate a statement. |
| 4767 | static EvalStmtResult EvaluateStmt(StmtResult &Result, EvalInfo &Info, |
| 4768 | const Stmt *S, const SwitchCase *Case) { |
| 4769 | if (!Info.nextStep(S)) |
| 4770 | return ESR_Failed; |
| 4771 | |
| 4772 | // If we're hunting down a 'case' or 'default' label, recurse through |
| 4773 | // substatements until we hit the label. |
| 4774 | if (Case) { |
| 4775 | switch (S->getStmtClass()) { |
| 4776 | case Stmt::CompoundStmtClass: |
| 4777 | // FIXME: Precompute which substatement of a compound statement we |
| 4778 | // would jump to, and go straight there rather than performing a |
| 4779 | // linear scan each time. |
| 4780 | case Stmt::LabelStmtClass: |
| 4781 | case Stmt::AttributedStmtClass: |
| 4782 | case Stmt::DoStmtClass: |
| 4783 | break; |
| 4784 | |
| 4785 | case Stmt::CaseStmtClass: |
| 4786 | case Stmt::DefaultStmtClass: |
| 4787 | if (Case == S) |
| 4788 | Case = nullptr; |
| 4789 | break; |
| 4790 | |
| 4791 | case Stmt::IfStmtClass: { |
| 4792 | // FIXME: Precompute which side of an 'if' we would jump to, and go |
| 4793 | // straight there rather than scanning both sides. |
| 4794 | const IfStmt *IS = cast<IfStmt>(S); |
| 4795 | |
| 4796 | // Wrap the evaluation in a block scope, in case it's a DeclStmt |
| 4797 | // preceded by our switch label. |
| 4798 | BlockScopeRAII Scope(Info); |
| 4799 | |
| 4800 | // Step into the init statement in case it brings an (uninitialized) |
| 4801 | // variable into scope. |
| 4802 | if (const Stmt *Init = IS->getInit()) { |
| 4803 | EvalStmtResult ESR = EvaluateStmt(Result, Info, Init, Case); |
| 4804 | if (ESR != ESR_CaseNotFound) { |
| 4805 | assert(ESR != ESR_Succeeded)((ESR != ESR_Succeeded) ? static_cast<void> (0) : __assert_fail ("ESR != ESR_Succeeded", "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 4805, __PRETTY_FUNCTION__)); |
| 4806 | return ESR; |
| 4807 | } |
| 4808 | } |
| 4809 | |
| 4810 | // Condition variable must be initialized if it exists. |
| 4811 | // FIXME: We can skip evaluating the body if there's a condition |
| 4812 | // variable, as there can't be any case labels within it. |
| 4813 | // (The same is true for 'for' statements.) |
| 4814 | |
| 4815 | EvalStmtResult ESR = EvaluateStmt(Result, Info, IS->getThen(), Case); |
| 4816 | if (ESR == ESR_Failed) |
| 4817 | return ESR; |
| 4818 | if (ESR != ESR_CaseNotFound) |
| 4819 | return Scope.destroy() ? ESR : ESR_Failed; |
| 4820 | if (!IS->getElse()) |
| 4821 | return ESR_CaseNotFound; |
| 4822 | |
| 4823 | ESR = EvaluateStmt(Result, Info, IS->getElse(), Case); |
| 4824 | if (ESR == ESR_Failed) |
| 4825 | return ESR; |
| 4826 | if (ESR != ESR_CaseNotFound) |
| 4827 | return Scope.destroy() ? ESR : ESR_Failed; |
| 4828 | return ESR_CaseNotFound; |
| 4829 | } |
| 4830 | |
| 4831 | case Stmt::WhileStmtClass: { |
| 4832 | EvalStmtResult ESR = |
| 4833 | EvaluateLoopBody(Result, Info, cast<WhileStmt>(S)->getBody(), Case); |
| 4834 | if (ESR != ESR_Continue) |
| 4835 | return ESR; |
| 4836 | break; |
| 4837 | } |
| 4838 | |
| 4839 | case Stmt::ForStmtClass: { |
| 4840 | const ForStmt *FS = cast<ForStmt>(S); |
| 4841 | BlockScopeRAII Scope(Info); |
| 4842 | |
| 4843 | // Step into the init statement in case it brings an (uninitialized) |
| 4844 | // variable into scope. |
| 4845 | if (const Stmt *Init = FS->getInit()) { |
| 4846 | EvalStmtResult ESR = EvaluateStmt(Result, Info, Init, Case); |
| 4847 | if (ESR != ESR_CaseNotFound) { |
| 4848 | assert(ESR != ESR_Succeeded)((ESR != ESR_Succeeded) ? static_cast<void> (0) : __assert_fail ("ESR != ESR_Succeeded", "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 4848, __PRETTY_FUNCTION__)); |
| 4849 | return ESR; |
| 4850 | } |
| 4851 | } |
| 4852 | |
| 4853 | EvalStmtResult ESR = |
| 4854 | EvaluateLoopBody(Result, Info, FS->getBody(), Case); |
| 4855 | if (ESR != ESR_Continue) |
| 4856 | return ESR; |
| 4857 | if (FS->getInc()) { |
| 4858 | FullExpressionRAII IncScope(Info); |
| 4859 | if (!EvaluateIgnoredValue(Info, FS->getInc()) || !IncScope.destroy()) |
| 4860 | return ESR_Failed; |
| 4861 | } |
| 4862 | break; |
| 4863 | } |
| 4864 | |
| 4865 | case Stmt::DeclStmtClass: { |
| 4866 | // Start the lifetime of any uninitialized variables we encounter. They |
| 4867 | // might be used by the selected branch of the switch. |
| 4868 | const DeclStmt *DS = cast<DeclStmt>(S); |
| 4869 | for (const auto *D : DS->decls()) { |
| 4870 | if (const auto *VD = dyn_cast<VarDecl>(D)) { |
| 4871 | if (VD->hasLocalStorage() && !VD->getInit()) |
| 4872 | if (!EvaluateVarDecl(Info, VD)) |
| 4873 | return ESR_Failed; |
| 4874 | // FIXME: If the variable has initialization that can't be jumped |
| 4875 | // over, bail out of any immediately-surrounding compound-statement |
| 4876 | // too. There can't be any case labels here. |
| 4877 | } |
| 4878 | } |
| 4879 | return ESR_CaseNotFound; |
| 4880 | } |
| 4881 | |
| 4882 | default: |
| 4883 | return ESR_CaseNotFound; |
| 4884 | } |
| 4885 | } |
| 4886 | |
| 4887 | switch (S->getStmtClass()) { |
| 4888 | default: |
| 4889 | if (const Expr *E = dyn_cast<Expr>(S)) { |
| 4890 | // Don't bother evaluating beyond an expression-statement which couldn't |
| 4891 | // be evaluated. |
| 4892 | // FIXME: Do we need the FullExpressionRAII object here? |
| 4893 | // VisitExprWithCleanups should create one when necessary. |
| 4894 | FullExpressionRAII Scope(Info); |
| 4895 | if (!EvaluateIgnoredValue(Info, E) || !Scope.destroy()) |
| 4896 | return ESR_Failed; |
| 4897 | return ESR_Succeeded; |
| 4898 | } |
| 4899 | |
| 4900 | Info.FFDiag(S->getBeginLoc()); |
| 4901 | return ESR_Failed; |
| 4902 | |
| 4903 | case Stmt::NullStmtClass: |
| 4904 | return ESR_Succeeded; |
| 4905 | |
| 4906 | case Stmt::DeclStmtClass: { |
| 4907 | const DeclStmt *DS = cast<DeclStmt>(S); |
| 4908 | for (const auto *D : DS->decls()) { |
| 4909 | // Each declaration initialization is its own full-expression. |
| 4910 | FullExpressionRAII Scope(Info); |
| 4911 | if (!EvaluateDecl(Info, D) && !Info.noteFailure()) |
| 4912 | return ESR_Failed; |
| 4913 | if (!Scope.destroy()) |
| 4914 | return ESR_Failed; |
| 4915 | } |
| 4916 | return ESR_Succeeded; |
| 4917 | } |
| 4918 | |
| 4919 | case Stmt::ReturnStmtClass: { |
| 4920 | const Expr *RetExpr = cast<ReturnStmt>(S)->getRetValue(); |
| 4921 | FullExpressionRAII Scope(Info); |
| 4922 | if (RetExpr && |
| 4923 | !(Result.Slot |
| 4924 | ? EvaluateInPlace(Result.Value, Info, *Result.Slot, RetExpr) |
| 4925 | : Evaluate(Result.Value, Info, RetExpr))) |
| 4926 | return ESR_Failed; |
| 4927 | return Scope.destroy() ? ESR_Returned : ESR_Failed; |
| 4928 | } |
| 4929 | |
| 4930 | case Stmt::CompoundStmtClass: { |
| 4931 | BlockScopeRAII Scope(Info); |
| 4932 | |
| 4933 | const CompoundStmt *CS = cast<CompoundStmt>(S); |
| 4934 | for (const auto *BI : CS->body()) { |
| 4935 | EvalStmtResult ESR = EvaluateStmt(Result, Info, BI, Case); |
| 4936 | if (ESR == ESR_Succeeded) |
| 4937 | Case = nullptr; |
| 4938 | else if (ESR != ESR_CaseNotFound) { |
| 4939 | if (ESR != ESR_Failed && !Scope.destroy()) |
| 4940 | return ESR_Failed; |
| 4941 | return ESR; |
| 4942 | } |
| 4943 | } |
| 4944 | if (Case) |
| 4945 | return ESR_CaseNotFound; |
| 4946 | return Scope.destroy() ? ESR_Succeeded : ESR_Failed; |
| 4947 | } |
| 4948 | |
| 4949 | case Stmt::IfStmtClass: { |
| 4950 | const IfStmt *IS = cast<IfStmt>(S); |
| 4951 | |
| 4952 | // Evaluate the condition, as either a var decl or as an expression. |
| 4953 | BlockScopeRAII Scope(Info); |
| 4954 | if (const Stmt *Init = IS->getInit()) { |
| 4955 | EvalStmtResult ESR = EvaluateStmt(Result, Info, Init); |
| 4956 | if (ESR != ESR_Succeeded) { |
| 4957 | if (ESR != ESR_Failed && !Scope.destroy()) |
| 4958 | return ESR_Failed; |
| 4959 | return ESR; |
| 4960 | } |
| 4961 | } |
| 4962 | bool Cond; |
| 4963 | if (!EvaluateCond(Info, IS->getConditionVariable(), IS->getCond(), Cond)) |
| 4964 | return ESR_Failed; |
| 4965 | |
| 4966 | if (const Stmt *SubStmt = Cond ? IS->getThen() : IS->getElse()) { |
| 4967 | EvalStmtResult ESR = EvaluateStmt(Result, Info, SubStmt); |
| 4968 | if (ESR != ESR_Succeeded) { |
| 4969 | if (ESR != ESR_Failed && !Scope.destroy()) |
| 4970 | return ESR_Failed; |
| 4971 | return ESR; |
| 4972 | } |
| 4973 | } |
| 4974 | return Scope.destroy() ? ESR_Succeeded : ESR_Failed; |
| 4975 | } |
| 4976 | |
| 4977 | case Stmt::WhileStmtClass: { |
| 4978 | const WhileStmt *WS = cast<WhileStmt>(S); |
| 4979 | while (true) { |
| 4980 | BlockScopeRAII Scope(Info); |
| 4981 | bool Continue; |
| 4982 | if (!EvaluateCond(Info, WS->getConditionVariable(), WS->getCond(), |
| 4983 | Continue)) |
| 4984 | return ESR_Failed; |
| 4985 | if (!Continue) |
| 4986 | break; |
| 4987 | |
| 4988 | EvalStmtResult ESR = EvaluateLoopBody(Result, Info, WS->getBody()); |
| 4989 | if (ESR != ESR_Continue) { |
| 4990 | if (ESR != ESR_Failed && !Scope.destroy()) |
| 4991 | return ESR_Failed; |
| 4992 | return ESR; |
| 4993 | } |
| 4994 | if (!Scope.destroy()) |
| 4995 | return ESR_Failed; |
| 4996 | } |
| 4997 | return ESR_Succeeded; |
| 4998 | } |
| 4999 | |
| 5000 | case Stmt::DoStmtClass: { |
| 5001 | const DoStmt *DS = cast<DoStmt>(S); |
| 5002 | bool Continue; |
| 5003 | do { |
| 5004 | EvalStmtResult ESR = EvaluateLoopBody(Result, Info, DS->getBody(), Case); |
| 5005 | if (ESR != ESR_Continue) |
| 5006 | return ESR; |
| 5007 | Case = nullptr; |
| 5008 | |
| 5009 | FullExpressionRAII CondScope(Info); |
| 5010 | if (!EvaluateAsBooleanCondition(DS->getCond(), Continue, Info) || |
| 5011 | !CondScope.destroy()) |
| 5012 | return ESR_Failed; |
| 5013 | } while (Continue); |
| 5014 | return ESR_Succeeded; |
| 5015 | } |
| 5016 | |
| 5017 | case Stmt::ForStmtClass: { |
| 5018 | const ForStmt *FS = cast<ForStmt>(S); |
| 5019 | BlockScopeRAII ForScope(Info); |
| 5020 | if (FS->getInit()) { |
| 5021 | EvalStmtResult ESR = EvaluateStmt(Result, Info, FS->getInit()); |
| 5022 | if (ESR != ESR_Succeeded) { |
| 5023 | if (ESR != ESR_Failed && !ForScope.destroy()) |
| 5024 | return ESR_Failed; |
| 5025 | return ESR; |
| 5026 | } |
| 5027 | } |
| 5028 | while (true) { |
| 5029 | BlockScopeRAII IterScope(Info); |
| 5030 | bool Continue = true; |
| 5031 | if (FS->getCond() && !EvaluateCond(Info, FS->getConditionVariable(), |
| 5032 | FS->getCond(), Continue)) |
| 5033 | return ESR_Failed; |
| 5034 | if (!Continue) |
| 5035 | break; |
| 5036 | |
| 5037 | EvalStmtResult ESR = EvaluateLoopBody(Result, Info, FS->getBody()); |
| 5038 | if (ESR != ESR_Continue) { |
| 5039 | if (ESR != ESR_Failed && (!IterScope.destroy() || !ForScope.destroy())) |
| 5040 | return ESR_Failed; |
| 5041 | return ESR; |
| 5042 | } |
| 5043 | |
| 5044 | if (FS->getInc()) { |
| 5045 | FullExpressionRAII IncScope(Info); |
| 5046 | if (!EvaluateIgnoredValue(Info, FS->getInc()) || !IncScope.destroy()) |
| 5047 | return ESR_Failed; |
| 5048 | } |
| 5049 | |
| 5050 | if (!IterScope.destroy()) |
| 5051 | return ESR_Failed; |
| 5052 | } |
| 5053 | return ForScope.destroy() ? ESR_Succeeded : ESR_Failed; |
| 5054 | } |
| 5055 | |
| 5056 | case Stmt::CXXForRangeStmtClass: { |
| 5057 | const CXXForRangeStmt *FS = cast<CXXForRangeStmt>(S); |
| 5058 | BlockScopeRAII Scope(Info); |
| 5059 | |
| 5060 | // Evaluate the init-statement if present. |
| 5061 | if (FS->getInit()) { |
| 5062 | EvalStmtResult ESR = EvaluateStmt(Result, Info, FS->getInit()); |
| 5063 | if (ESR != ESR_Succeeded) { |
| 5064 | if (ESR != ESR_Failed && !Scope.destroy()) |
| 5065 | return ESR_Failed; |
| 5066 | return ESR; |
| 5067 | } |
| 5068 | } |
| 5069 | |
| 5070 | // Initialize the __range variable. |
| 5071 | EvalStmtResult ESR = EvaluateStmt(Result, Info, FS->getRangeStmt()); |
| 5072 | if (ESR != ESR_Succeeded) { |
| 5073 | if (ESR != ESR_Failed && !Scope.destroy()) |
| 5074 | return ESR_Failed; |
| 5075 | return ESR; |
| 5076 | } |
| 5077 | |
| 5078 | // Create the __begin and __end iterators. |
| 5079 | ESR = EvaluateStmt(Result, Info, FS->getBeginStmt()); |
| 5080 | if (ESR != ESR_Succeeded) { |
| 5081 | if (ESR != ESR_Failed && !Scope.destroy()) |
| 5082 | return ESR_Failed; |
| 5083 | return ESR; |
| 5084 | } |
| 5085 | ESR = EvaluateStmt(Result, Info, FS->getEndStmt()); |
| 5086 | if (ESR != ESR_Succeeded) { |
| 5087 | if (ESR != ESR_Failed && !Scope.destroy()) |
| 5088 | return ESR_Failed; |
| 5089 | return ESR; |
| 5090 | } |
| 5091 | |
| 5092 | while (true) { |
| 5093 | // Condition: __begin != __end. |
| 5094 | { |
| 5095 | bool Continue = true; |
| 5096 | FullExpressionRAII CondExpr(Info); |
| 5097 | if (!EvaluateAsBooleanCondition(FS->getCond(), Continue, Info)) |
| 5098 | return ESR_Failed; |
| 5099 | if (!Continue) |
| 5100 | break; |
| 5101 | } |
| 5102 | |
| 5103 | // User's variable declaration, initialized by *__begin. |
| 5104 | BlockScopeRAII InnerScope(Info); |
| 5105 | ESR = EvaluateStmt(Result, Info, FS->getLoopVarStmt()); |
| 5106 | if (ESR != ESR_Succeeded) { |
| 5107 | if (ESR != ESR_Failed && (!InnerScope.destroy() || !Scope.destroy())) |
| 5108 | return ESR_Failed; |
| 5109 | return ESR; |
| 5110 | } |
| 5111 | |
| 5112 | // Loop body. |
| 5113 | ESR = EvaluateLoopBody(Result, Info, FS->getBody()); |
| 5114 | if (ESR != ESR_Continue) { |
| 5115 | if (ESR != ESR_Failed && (!InnerScope.destroy() || !Scope.destroy())) |
| 5116 | return ESR_Failed; |
| 5117 | return ESR; |
| 5118 | } |
| 5119 | |
| 5120 | // Increment: ++__begin |
| 5121 | if (!EvaluateIgnoredValue(Info, FS->getInc())) |
| 5122 | return ESR_Failed; |
| 5123 | |
| 5124 | if (!InnerScope.destroy()) |
| 5125 | return ESR_Failed; |
| 5126 | } |
| 5127 | |
| 5128 | return Scope.destroy() ? ESR_Succeeded : ESR_Failed; |
| 5129 | } |
| 5130 | |
| 5131 | case Stmt::SwitchStmtClass: |
| 5132 | return EvaluateSwitch(Result, Info, cast<SwitchStmt>(S)); |
| 5133 | |
| 5134 | case Stmt::ContinueStmtClass: |
| 5135 | return ESR_Continue; |
| 5136 | |
| 5137 | case Stmt::BreakStmtClass: |
| 5138 | return ESR_Break; |
| 5139 | |
| 5140 | case Stmt::LabelStmtClass: |
| 5141 | return EvaluateStmt(Result, Info, cast<LabelStmt>(S)->getSubStmt(), Case); |
| 5142 | |
| 5143 | case Stmt::AttributedStmtClass: |
| 5144 | // As a general principle, C++11 attributes can be ignored without |
| 5145 | // any semantic impact. |
| 5146 | return EvaluateStmt(Result, Info, cast<AttributedStmt>(S)->getSubStmt(), |
| 5147 | Case); |
| 5148 | |
| 5149 | case Stmt::CaseStmtClass: |
| 5150 | case Stmt::DefaultStmtClass: |
| 5151 | return EvaluateStmt(Result, Info, cast<SwitchCase>(S)->getSubStmt(), Case); |
| 5152 | case Stmt::CXXTryStmtClass: |
| 5153 | // Evaluate try blocks by evaluating all sub statements. |
| 5154 | return EvaluateStmt(Result, Info, cast<CXXTryStmt>(S)->getTryBlock(), Case); |
| 5155 | } |
| 5156 | } |
| 5157 | |
| 5158 | /// CheckTrivialDefaultConstructor - Check whether a constructor is a trivial |
| 5159 | /// default constructor. If so, we'll fold it whether or not it's marked as |
| 5160 | /// constexpr. If it is marked as constexpr, we will never implicitly define it, |
| 5161 | /// so we need special handling. |
| 5162 | static bool CheckTrivialDefaultConstructor(EvalInfo &Info, SourceLocation Loc, |
| 5163 | const CXXConstructorDecl *CD, |
| 5164 | bool IsValueInitialization) { |
| 5165 | if (!CD->isTrivial() || !CD->isDefaultConstructor()) |
| 5166 | return false; |
| 5167 | |
| 5168 | // Value-initialization does not call a trivial default constructor, so such a |
| 5169 | // call is a core constant expression whether or not the constructor is |
| 5170 | // constexpr. |
| 5171 | if (!CD->isConstexpr() && !IsValueInitialization) { |
| 5172 | if (Info.getLangOpts().CPlusPlus11) { |
| 5173 | // FIXME: If DiagDecl is an implicitly-declared special member function, |
| 5174 | // we should be much more explicit about why it's not constexpr. |
| 5175 | Info.CCEDiag(Loc, diag::note_constexpr_invalid_function, 1) |
| 5176 | << /*IsConstexpr*/0 << /*IsConstructor*/1 << CD; |
| 5177 | Info.Note(CD->getLocation(), diag::note_declared_at); |
| 5178 | } else { |
| 5179 | Info.CCEDiag(Loc, diag::note_invalid_subexpr_in_const_expr); |
| 5180 | } |
| 5181 | } |
| 5182 | return true; |
| 5183 | } |
| 5184 | |
| 5185 | /// CheckConstexprFunction - Check that a function can be called in a constant |
| 5186 | /// expression. |
| 5187 | static bool CheckConstexprFunction(EvalInfo &Info, SourceLocation CallLoc, |
| 5188 | const FunctionDecl *Declaration, |
| 5189 | const FunctionDecl *Definition, |
| 5190 | const Stmt *Body) { |
| 5191 | // Potential constant expressions can contain calls to declared, but not yet |
| 5192 | // defined, constexpr functions. |
| 5193 | if (Info.checkingPotentialConstantExpression() && !Definition && |
| 5194 | Declaration->isConstexpr()) |
| 5195 | return false; |
| 5196 | |
| 5197 | // Bail out if the function declaration itself is invalid. We will |
| 5198 | // have produced a relevant diagnostic while parsing it, so just |
| 5199 | // note the problematic sub-expression. |
| 5200 | if (Declaration->isInvalidDecl()) { |
| 5201 | Info.FFDiag(CallLoc, diag::note_invalid_subexpr_in_const_expr); |
| 5202 | return false; |
| 5203 | } |
| 5204 | |
| 5205 | // DR1872: An instantiated virtual constexpr function can't be called in a |
| 5206 | // constant expression (prior to C++20). We can still constant-fold such a |
| 5207 | // call. |
| 5208 | if (!Info.Ctx.getLangOpts().CPlusPlus20 && isa<CXXMethodDecl>(Declaration) && |
| 5209 | cast<CXXMethodDecl>(Declaration)->isVirtual()) |
| 5210 | Info.CCEDiag(CallLoc, diag::note_constexpr_virtual_call); |
| 5211 | |
| 5212 | if (Definition && Definition->isInvalidDecl()) { |
| 5213 | Info.FFDiag(CallLoc, diag::note_invalid_subexpr_in_const_expr); |
| 5214 | return false; |
| 5215 | } |
| 5216 | |
| 5217 | if (const auto *CtorDecl = dyn_cast_or_null<CXXConstructorDecl>(Definition)) { |
| 5218 | for (const auto *InitExpr : CtorDecl->inits()) { |
| 5219 | if (InitExpr->getInit() && InitExpr->getInit()->containsErrors()) |
| 5220 | return false; |
| 5221 | } |
| 5222 | } |
| 5223 | |
| 5224 | // Can we evaluate this function call? |
| 5225 | if (Definition && Definition->isConstexpr() && Body) |
| 5226 | return true; |
| 5227 | |
| 5228 | if (Info.getLangOpts().CPlusPlus11) { |
| 5229 | const FunctionDecl *DiagDecl = Definition ? Definition : Declaration; |
| 5230 | |
| 5231 | // If this function is not constexpr because it is an inherited |
| 5232 | // non-constexpr constructor, diagnose that directly. |
| 5233 | auto *CD = dyn_cast<CXXConstructorDecl>(DiagDecl); |
| 5234 | if (CD && CD->isInheritingConstructor()) { |
| 5235 | auto *Inherited = CD->getInheritedConstructor().getConstructor(); |
| 5236 | if (!Inherited->isConstexpr()) |
| 5237 | DiagDecl = CD = Inherited; |
| 5238 | } |
| 5239 | |
| 5240 | // FIXME: If DiagDecl is an implicitly-declared special member function |
| 5241 | // or an inheriting constructor, we should be much more explicit about why |
| 5242 | // it's not constexpr. |
| 5243 | if (CD && CD->isInheritingConstructor()) |
| 5244 | Info.FFDiag(CallLoc, diag::note_constexpr_invalid_inhctor, 1) |
| 5245 | << CD->getInheritedConstructor().getConstructor()->getParent(); |
| 5246 | else |
| 5247 | Info.FFDiag(CallLoc, diag::note_constexpr_invalid_function, 1) |
| 5248 | << DiagDecl->isConstexpr() << (bool)CD << DiagDecl; |
| 5249 | Info.Note(DiagDecl->getLocation(), diag::note_declared_at); |
| 5250 | } else { |
| 5251 | Info.FFDiag(CallLoc, diag::note_invalid_subexpr_in_const_expr); |
| 5252 | } |
| 5253 | return false; |
| 5254 | } |
| 5255 | |
| 5256 | namespace { |
| 5257 | struct CheckDynamicTypeHandler { |
| 5258 | AccessKinds AccessKind; |
| 5259 | typedef bool result_type; |
| 5260 | bool failed() { return false; } |
| 5261 | bool found(APValue &Subobj, QualType SubobjType) { return true; } |
| 5262 | bool found(APSInt &Value, QualType SubobjType) { return true; } |
| 5263 | bool found(APFloat &Value, QualType SubobjType) { return true; } |
| 5264 | }; |
| 5265 | } // end anonymous namespace |
| 5266 | |
| 5267 | /// Check that we can access the notional vptr of an object / determine its |
| 5268 | /// dynamic type. |
| 5269 | static bool checkDynamicType(EvalInfo &Info, const Expr *E, const LValue &This, |
| 5270 | AccessKinds AK, bool Polymorphic) { |
| 5271 | if (This.Designator.Invalid) |
| 5272 | return false; |
| 5273 | |
| 5274 | CompleteObject Obj = findCompleteObject(Info, E, AK, This, QualType()); |
| 5275 | |
| 5276 | if (!Obj) |
| 5277 | return false; |
| 5278 | |
| 5279 | if (!Obj.Value) { |
| 5280 | // The object is not usable in constant expressions, so we can't inspect |
| 5281 | // its value to see if it's in-lifetime or what the active union members |
| 5282 | // are. We can still check for a one-past-the-end lvalue. |
| 5283 | if (This.Designator.isOnePastTheEnd() || |
| 5284 | This.Designator.isMostDerivedAnUnsizedArray()) { |
| 5285 | Info.FFDiag(E, This.Designator.isOnePastTheEnd() |
| 5286 | ? diag::note_constexpr_access_past_end |
| 5287 | : diag::note_constexpr_access_unsized_array) |
| 5288 | << AK; |
| 5289 | return false; |
| 5290 | } else if (Polymorphic) { |
| 5291 | // Conservatively refuse to perform a polymorphic operation if we would |
| 5292 | // not be able to read a notional 'vptr' value. |
| 5293 | APValue Val; |
| 5294 | This.moveInto(Val); |
| 5295 | QualType StarThisType = |
| 5296 | Info.Ctx.getLValueReferenceType(This.Designator.getType(Info.Ctx)); |
| 5297 | Info.FFDiag(E, diag::note_constexpr_polymorphic_unknown_dynamic_type) |
| 5298 | << AK << Val.getAsString(Info.Ctx, StarThisType); |
| 5299 | return false; |
| 5300 | } |
| 5301 | return true; |
| 5302 | } |
| 5303 | |
| 5304 | CheckDynamicTypeHandler Handler{AK}; |
| 5305 | return Obj && findSubobject(Info, E, Obj, This.Designator, Handler); |
| 5306 | } |
| 5307 | |
| 5308 | /// Check that the pointee of the 'this' pointer in a member function call is |
| 5309 | /// either within its lifetime or in its period of construction or destruction. |
| 5310 | static bool |
| 5311 | checkNonVirtualMemberCallThisPointer(EvalInfo &Info, const Expr *E, |
| 5312 | const LValue &This, |
| 5313 | const CXXMethodDecl *NamedMember) { |
| 5314 | return checkDynamicType( |
| 5315 | Info, E, This, |
| 5316 | isa<CXXDestructorDecl>(NamedMember) ? AK_Destroy : AK_MemberCall, false); |
| 5317 | } |
| 5318 | |
| 5319 | struct DynamicType { |
| 5320 | /// The dynamic class type of the object. |
| 5321 | const CXXRecordDecl *Type; |
| 5322 | /// The corresponding path length in the lvalue. |
| 5323 | unsigned PathLength; |
| 5324 | }; |
| 5325 | |
| 5326 | static const CXXRecordDecl *getBaseClassType(SubobjectDesignator &Designator, |
| 5327 | unsigned PathLength) { |
| 5328 | assert(PathLength >= Designator.MostDerivedPathLength && PathLength <=((PathLength >= Designator.MostDerivedPathLength && PathLength <= Designator.Entries.size() && "invalid path length" ) ? static_cast<void> (0) : __assert_fail ("PathLength >= Designator.MostDerivedPathLength && PathLength <= Designator.Entries.size() && \"invalid path length\"" , "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 5329, __PRETTY_FUNCTION__)) |
| 5329 | Designator.Entries.size() && "invalid path length")((PathLength >= Designator.MostDerivedPathLength && PathLength <= Designator.Entries.size() && "invalid path length" ) ? static_cast<void> (0) : __assert_fail ("PathLength >= Designator.MostDerivedPathLength && PathLength <= Designator.Entries.size() && \"invalid path length\"" , "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 5329, __PRETTY_FUNCTION__)); |
| 5330 | return (PathLength == Designator.MostDerivedPathLength) |
| 5331 | ? Designator.MostDerivedType->getAsCXXRecordDecl() |
| 5332 | : getAsBaseClass(Designator.Entries[PathLength - 1]); |
| 5333 | } |
| 5334 | |
| 5335 | /// Determine the dynamic type of an object. |
| 5336 | static Optional<DynamicType> ComputeDynamicType(EvalInfo &Info, const Expr *E, |
| 5337 | LValue &This, AccessKinds AK) { |
| 5338 | // If we don't have an lvalue denoting an object of class type, there is no |
| 5339 | // meaningful dynamic type. (We consider objects of non-class type to have no |
| 5340 | // dynamic type.) |
| 5341 | if (!checkDynamicType(Info, E, This, AK, true)) |
| 5342 | return None; |
| 5343 | |
| 5344 | // Refuse to compute a dynamic type in the presence of virtual bases. This |
| 5345 | // shouldn't happen other than in constant-folding situations, since literal |
| 5346 | // types can't have virtual bases. |
| 5347 | // |
| 5348 | // Note that consumers of DynamicType assume that the type has no virtual |
| 5349 | // bases, and will need modifications if this restriction is relaxed. |
| 5350 | const CXXRecordDecl *Class = |
| 5351 | This.Designator.MostDerivedType->getAsCXXRecordDecl(); |
| 5352 | if (!Class || Class->getNumVBases()) { |
| 5353 | Info.FFDiag(E); |
| 5354 | return None; |
| 5355 | } |
| 5356 | |
| 5357 | // FIXME: For very deep class hierarchies, it might be beneficial to use a |
| 5358 | // binary search here instead. But the overwhelmingly common case is that |
| 5359 | // we're not in the middle of a constructor, so it probably doesn't matter |
| 5360 | // in practice. |
| 5361 | ArrayRef<APValue::LValuePathEntry> Path = This.Designator.Entries; |
| 5362 | for (unsigned PathLength = This.Designator.MostDerivedPathLength; |
| 5363 | PathLength <= Path.size(); ++PathLength) { |
| 5364 | switch (Info.isEvaluatingCtorDtor(This.getLValueBase(), |
| 5365 | Path.slice(0, PathLength))) { |
| 5366 | case ConstructionPhase::Bases: |
| 5367 | case ConstructionPhase::DestroyingBases: |
| 5368 | // We're constructing or destroying a base class. This is not the dynamic |
| 5369 | // type. |
| 5370 | break; |
| 5371 | |
| 5372 | case ConstructionPhase::None: |
| 5373 | case ConstructionPhase::AfterBases: |
| 5374 | case ConstructionPhase::AfterFields: |
| 5375 | case ConstructionPhase::Destroying: |
| 5376 | // We've finished constructing the base classes and not yet started |
| 5377 | // destroying them again, so this is the dynamic type. |
| 5378 | return DynamicType{getBaseClassType(This.Designator, PathLength), |
| 5379 | PathLength}; |
| 5380 | } |
| 5381 | } |
| 5382 | |
| 5383 | // CWG issue 1517: we're constructing a base class of the object described by |
| 5384 | // 'This', so that object has not yet begun its period of construction and |
| 5385 | // any polymorphic operation on it results in undefined behavior. |
| 5386 | Info.FFDiag(E); |
| 5387 | return None; |
| 5388 | } |
| 5389 | |
| 5390 | /// Perform virtual dispatch. |
| 5391 | static const CXXMethodDecl *HandleVirtualDispatch( |
| 5392 | EvalInfo &Info, const Expr *E, LValue &This, const CXXMethodDecl *Found, |
| 5393 | llvm::SmallVectorImpl<QualType> &CovariantAdjustmentPath) { |
| 5394 | Optional<DynamicType> DynType = ComputeDynamicType( |
| 5395 | Info, E, This, |
| 5396 | isa<CXXDestructorDecl>(Found) ? AK_Destroy : AK_MemberCall); |
| 5397 | if (!DynType) |
| 5398 | return nullptr; |
| 5399 | |
| 5400 | // Find the final overrider. It must be declared in one of the classes on the |
| 5401 | // path from the dynamic type to the static type. |
| 5402 | // FIXME: If we ever allow literal types to have virtual base classes, that |
| 5403 | // won't be true. |
| 5404 | const CXXMethodDecl *Callee = Found; |
| 5405 | unsigned PathLength = DynType->PathLength; |
| 5406 | for (/**/; PathLength <= This.Designator.Entries.size(); ++PathLength) { |
| 5407 | const CXXRecordDecl *Class = getBaseClassType(This.Designator, PathLength); |
| 5408 | const CXXMethodDecl *Overrider = |
| 5409 | Found->getCorrespondingMethodDeclaredInClass(Class, false); |
| 5410 | if (Overrider) { |
| 5411 | Callee = Overrider; |
| 5412 | break; |
| 5413 | } |
| 5414 | } |
| 5415 | |
| 5416 | // C++2a [class.abstract]p6: |
| 5417 | // the effect of making a virtual call to a pure virtual function [...] is |
| 5418 | // undefined |
| 5419 | if (Callee->isPure()) { |
| 5420 | Info.FFDiag(E, diag::note_constexpr_pure_virtual_call, 1) << Callee; |
| 5421 | Info.Note(Callee->getLocation(), diag::note_declared_at); |
| 5422 | return nullptr; |
| 5423 | } |
| 5424 | |
| 5425 | // If necessary, walk the rest of the path to determine the sequence of |
| 5426 | // covariant adjustment steps to apply. |
| 5427 | if (!Info.Ctx.hasSameUnqualifiedType(Callee->getReturnType(), |
| 5428 | Found->getReturnType())) { |
| 5429 | CovariantAdjustmentPath.push_back(Callee->getReturnType()); |
| 5430 | for (unsigned CovariantPathLength = PathLength + 1; |
| 5431 | CovariantPathLength != This.Designator.Entries.size(); |
| 5432 | ++CovariantPathLength) { |
| 5433 | const CXXRecordDecl *NextClass = |
| 5434 | getBaseClassType(This.Designator, CovariantPathLength); |
| 5435 | const CXXMethodDecl *Next = |
| 5436 | Found->getCorrespondingMethodDeclaredInClass(NextClass, false); |
| 5437 | if (Next && !Info.Ctx.hasSameUnqualifiedType( |
| 5438 | Next->getReturnType(), CovariantAdjustmentPath.back())) |
| 5439 | CovariantAdjustmentPath.push_back(Next->getReturnType()); |
| 5440 | } |
| 5441 | if (!Info.Ctx.hasSameUnqualifiedType(Found->getReturnType(), |
| 5442 | CovariantAdjustmentPath.back())) |
| 5443 | CovariantAdjustmentPath.push_back(Found->getReturnType()); |
| 5444 | } |
| 5445 | |
| 5446 | // Perform 'this' adjustment. |
| 5447 | if (!CastToDerivedClass(Info, E, This, Callee->getParent(), PathLength)) |
| 5448 | return nullptr; |
| 5449 | |
| 5450 | return Callee; |
| 5451 | } |
| 5452 | |
| 5453 | /// Perform the adjustment from a value returned by a virtual function to |
| 5454 | /// a value of the statically expected type, which may be a pointer or |
| 5455 | /// reference to a base class of the returned type. |
| 5456 | static bool HandleCovariantReturnAdjustment(EvalInfo &Info, const Expr *E, |
| 5457 | APValue &Result, |
| 5458 | ArrayRef<QualType> Path) { |
| 5459 | assert(Result.isLValue() &&((Result.isLValue() && "unexpected kind of APValue for covariant return" ) ? static_cast<void> (0) : __assert_fail ("Result.isLValue() && \"unexpected kind of APValue for covariant return\"" , "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 5460, __PRETTY_FUNCTION__)) |
| 5460 | "unexpected kind of APValue for covariant return")((Result.isLValue() && "unexpected kind of APValue for covariant return" ) ? static_cast<void> (0) : __assert_fail ("Result.isLValue() && \"unexpected kind of APValue for covariant return\"" , "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 5460, __PRETTY_FUNCTION__)); |
| 5461 | if (Result.isNullPointer()) |
| 5462 | return true; |
| 5463 | |
| 5464 | LValue LVal; |
| 5465 | LVal.setFrom(Info.Ctx, Result); |
| 5466 | |
| 5467 | const CXXRecordDecl *OldClass = Path[0]->getPointeeCXXRecordDecl(); |
| 5468 | for (unsigned I = 1; I != Path.size(); ++I) { |
| 5469 | const CXXRecordDecl *NewClass = Path[I]->getPointeeCXXRecordDecl(); |
| 5470 | assert(OldClass && NewClass && "unexpected kind of covariant return")((OldClass && NewClass && "unexpected kind of covariant return" ) ? static_cast<void> (0) : __assert_fail ("OldClass && NewClass && \"unexpected kind of covariant return\"" , "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 5470, __PRETTY_FUNCTION__)); |
| 5471 | if (OldClass != NewClass && |
| 5472 | !CastToBaseClass(Info, E, LVal, OldClass, NewClass)) |
| 5473 | return false; |
| 5474 | OldClass = NewClass; |
| 5475 | } |
| 5476 | |
| 5477 | LVal.moveInto(Result); |
| 5478 | return true; |
| 5479 | } |
| 5480 | |
| 5481 | /// Determine whether \p Base, which is known to be a direct base class of |
| 5482 | /// \p Derived, is a public base class. |
| 5483 | static bool isBaseClassPublic(const CXXRecordDecl *Derived, |
| 5484 | const CXXRecordDecl *Base) { |
| 5485 | for (const CXXBaseSpecifier &BaseSpec : Derived->bases()) { |
| 5486 | auto *BaseClass = BaseSpec.getType()->getAsCXXRecordDecl(); |
| 5487 | if (BaseClass && declaresSameEntity(BaseClass, Base)) |
| 5488 | return BaseSpec.getAccessSpecifier() == AS_public; |
| 5489 | } |
| 5490 | llvm_unreachable("Base is not a direct base of Derived")::llvm::llvm_unreachable_internal("Base is not a direct base of Derived" , "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 5490); |
| 5491 | } |
| 5492 | |
| 5493 | /// Apply the given dynamic cast operation on the provided lvalue. |
| 5494 | /// |
| 5495 | /// This implements the hard case of dynamic_cast, requiring a "runtime check" |
| 5496 | /// to find a suitable target subobject. |
| 5497 | static bool HandleDynamicCast(EvalInfo &Info, const ExplicitCastExpr *E, |
| 5498 | LValue &Ptr) { |
| 5499 | // We can't do anything with a non-symbolic pointer value. |
| 5500 | SubobjectDesignator &D = Ptr.Designator; |
| 5501 | if (D.Invalid) |
| 5502 | return false; |
| 5503 | |
| 5504 | // C++ [expr.dynamic.cast]p6: |
| 5505 | // If v is a null pointer value, the result is a null pointer value. |
| 5506 | if (Ptr.isNullPointer() && !E->isGLValue()) |
| 5507 | return true; |
| 5508 | |
| 5509 | // For all the other cases, we need the pointer to point to an object within |
| 5510 | // its lifetime / period of construction / destruction, and we need to know |
| 5511 | // its dynamic type. |
| 5512 | Optional<DynamicType> DynType = |
| 5513 | ComputeDynamicType(Info, E, Ptr, AK_DynamicCast); |
| 5514 | if (!DynType) |
| 5515 | return false; |
| 5516 | |
| 5517 | // C++ [expr.dynamic.cast]p7: |
| 5518 | // If T is "pointer to cv void", then the result is a pointer to the most |
| 5519 | // derived object |
| 5520 | if (E->getType()->isVoidPointerType()) |
| 5521 | return CastToDerivedClass(Info, E, Ptr, DynType->Type, DynType->PathLength); |
| 5522 | |
| 5523 | const CXXRecordDecl *C = E->getTypeAsWritten()->getPointeeCXXRecordDecl(); |
| 5524 | assert(C && "dynamic_cast target is not void pointer nor class")((C && "dynamic_cast target is not void pointer nor class" ) ? static_cast<void> (0) : __assert_fail ("C && \"dynamic_cast target is not void pointer nor class\"" , "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 5524, __PRETTY_FUNCTION__)); |
| 5525 | CanQualType CQT = Info.Ctx.getCanonicalType(Info.Ctx.getRecordType(C)); |
| 5526 | |
| 5527 | auto RuntimeCheckFailed = [&] (CXXBasePaths *Paths) { |
| 5528 | // C++ [expr.dynamic.cast]p9: |
| 5529 | if (!E->isGLValue()) { |
| 5530 | // The value of a failed cast to pointer type is the null pointer value |
| 5531 | // of the required result type. |
| 5532 | Ptr.setNull(Info.Ctx, E->getType()); |
| 5533 | return true; |
| 5534 | } |
| 5535 | |
| 5536 | // A failed cast to reference type throws [...] std::bad_cast. |
| 5537 | unsigned DiagKind; |
| 5538 | if (!Paths && (declaresSameEntity(DynType->Type, C) || |
| 5539 | DynType->Type->isDerivedFrom(C))) |
| 5540 | DiagKind = 0; |
| 5541 | else if (!Paths || Paths->begin() == Paths->end()) |
| 5542 | DiagKind = 1; |
| 5543 | else if (Paths->isAmbiguous(CQT)) |
| 5544 | DiagKind = 2; |
| 5545 | else { |
| 5546 | assert(Paths->front().Access != AS_public && "why did the cast fail?")((Paths->front().Access != AS_public && "why did the cast fail?" ) ? static_cast<void> (0) : __assert_fail ("Paths->front().Access != AS_public && \"why did the cast fail?\"" , "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 5546, __PRETTY_FUNCTION__)); |
| 5547 | DiagKind = 3; |
| 5548 | } |
| 5549 | Info.FFDiag(E, diag::note_constexpr_dynamic_cast_to_reference_failed) |
| 5550 | << DiagKind << Ptr.Designator.getType(Info.Ctx) |
| 5551 | << Info.Ctx.getRecordType(DynType->Type) |
| 5552 | << E->getType().getUnqualifiedType(); |
| 5553 | return false; |
| 5554 | }; |
| 5555 | |
| 5556 | // Runtime check, phase 1: |
| 5557 | // Walk from the base subobject towards the derived object looking for the |
| 5558 | // target type. |
| 5559 | for (int PathLength = Ptr.Designator.Entries.size(); |
| 5560 | PathLength >= (int)DynType->PathLength; --PathLength) { |
| 5561 | const CXXRecordDecl *Class = getBaseClassType(Ptr.Designator, PathLength); |
| 5562 | if (declaresSameEntity(Class, C)) |
| 5563 | return CastToDerivedClass(Info, E, Ptr, Class, PathLength); |
| 5564 | // We can only walk across public inheritance edges. |
| 5565 | if (PathLength > (int)DynType->PathLength && |
| 5566 | !isBaseClassPublic(getBaseClassType(Ptr.Designator, PathLength - 1), |
| 5567 | Class)) |
| 5568 | return RuntimeCheckFailed(nullptr); |
| 5569 | } |
| 5570 | |
| 5571 | // Runtime check, phase 2: |
| 5572 | // Search the dynamic type for an unambiguous public base of type C. |
| 5573 | CXXBasePaths Paths(/*FindAmbiguities=*/true, |
| 5574 | /*RecordPaths=*/true, /*DetectVirtual=*/false); |
| 5575 | if (DynType->Type->isDerivedFrom(C, Paths) && !Paths.isAmbiguous(CQT) && |
| 5576 | Paths.front().Access == AS_public) { |
| 5577 | // Downcast to the dynamic type... |
| 5578 | if (!CastToDerivedClass(Info, E, Ptr, DynType->Type, DynType->PathLength)) |
| 5579 | return false; |
| 5580 | // ... then upcast to the chosen base class subobject. |
| 5581 | for (CXXBasePathElement &Elem : Paths.front()) |
| 5582 | if (!HandleLValueBase(Info, E, Ptr, Elem.Class, Elem.Base)) |
| 5583 | return false; |
| 5584 | return true; |
| 5585 | } |
| 5586 | |
| 5587 | // Otherwise, the runtime check fails. |
| 5588 | return RuntimeCheckFailed(&Paths); |
| 5589 | } |
| 5590 | |
| 5591 | namespace { |
| 5592 | struct StartLifetimeOfUnionMemberHandler { |
| 5593 | EvalInfo &Info; |
| 5594 | const Expr *LHSExpr; |
| 5595 | const FieldDecl *Field; |
| 5596 | bool DuringInit; |
| 5597 | bool Failed = false; |
| 5598 | static const AccessKinds AccessKind = AK_Assign; |
| 5599 | |
| 5600 | typedef bool result_type; |
| 5601 | bool failed() { return Failed; } |
| 5602 | bool found(APValue &Subobj, QualType SubobjType) { |
| 5603 | // We are supposed to perform no initialization but begin the lifetime of |
| 5604 | // the object. We interpret that as meaning to do what default |
| 5605 | // initialization of the object would do if all constructors involved were |
| 5606 | // trivial: |
| 5607 | // * All base, non-variant member, and array element subobjects' lifetimes |
| 5608 | // begin |
| 5609 | // * No variant members' lifetimes begin |
| 5610 | // * All scalar subobjects whose lifetimes begin have indeterminate values |
| 5611 | assert(SubobjType->isUnionType())((SubobjType->isUnionType()) ? static_cast<void> (0) : __assert_fail ("SubobjType->isUnionType()", "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 5611, __PRETTY_FUNCTION__)); |
| 5612 | if (declaresSameEntity(Subobj.getUnionField(), Field)) { |
| 5613 | // This union member is already active. If it's also in-lifetime, there's |
| 5614 | // nothing to do. |
| 5615 | if (Subobj.getUnionValue().hasValue()) |
| 5616 | return true; |
| 5617 | } else if (DuringInit) { |
| 5618 | // We're currently in the process of initializing a different union |
| 5619 | // member. If we carried on, that initialization would attempt to |
| 5620 | // store to an inactive union member, resulting in undefined behavior. |
| 5621 | Info.FFDiag(LHSExpr, |
| 5622 | diag::note_constexpr_union_member_change_during_init); |
| 5623 | return false; |
| 5624 | } |
| 5625 | APValue Result; |
| 5626 | Failed = !getDefaultInitValue(Field->getType(), Result); |
| 5627 | Subobj.setUnion(Field, Result); |
| 5628 | return true; |
| 5629 | } |
| 5630 | bool found(APSInt &Value, QualType SubobjType) { |
| 5631 | llvm_unreachable("wrong value kind for union object")::llvm::llvm_unreachable_internal("wrong value kind for union object" , "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 5631); |
| 5632 | } |
| 5633 | bool found(APFloat &Value, QualType SubobjType) { |
| 5634 | llvm_unreachable("wrong value kind for union object")::llvm::llvm_unreachable_internal("wrong value kind for union object" , "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 5634); |
| 5635 | } |
| 5636 | }; |
| 5637 | } // end anonymous namespace |
| 5638 | |
| 5639 | const AccessKinds StartLifetimeOfUnionMemberHandler::AccessKind; |
| 5640 | |
| 5641 | /// Handle a builtin simple-assignment or a call to a trivial assignment |
| 5642 | /// operator whose left-hand side might involve a union member access. If it |
| 5643 | /// does, implicitly start the lifetime of any accessed union elements per |
| 5644 | /// C++20 [class.union]5. |
| 5645 | static bool HandleUnionActiveMemberChange(EvalInfo &Info, const Expr *LHSExpr, |
| 5646 | const LValue &LHS) { |
| 5647 | if (LHS.InvalidBase || LHS.Designator.Invalid) |
| 5648 | return false; |
| 5649 | |
| 5650 | llvm::SmallVector<std::pair<unsigned, const FieldDecl*>, 4> UnionPathLengths; |
| 5651 | // C++ [class.union]p5: |
| 5652 | // define the set S(E) of subexpressions of E as follows: |
| 5653 | unsigned PathLength = LHS.Designator.Entries.size(); |
| 5654 | for (const Expr *E = LHSExpr; E != nullptr;) { |
| 5655 | // -- If E is of the form A.B, S(E) contains the elements of S(A)... |
| 5656 | if (auto *ME = dyn_cast<MemberExpr>(E)) { |
| 5657 | auto *FD = dyn_cast<FieldDecl>(ME->getMemberDecl()); |
| 5658 | // Note that we can't implicitly start the lifetime of a reference, |
| 5659 | // so we don't need to proceed any further if we reach one. |
| 5660 | if (!FD || FD->getType()->isReferenceType()) |
| 5661 | break; |
| 5662 | |
| 5663 | // ... and also contains A.B if B names a union member ... |
| 5664 | if (FD->getParent()->isUnion()) { |
| 5665 | // ... of a non-class, non-array type, or of a class type with a |
| 5666 | // trivial default constructor that is not deleted, or an array of |
| 5667 | // such types. |
| 5668 | auto *RD = |
| 5669 | FD->getType()->getBaseElementTypeUnsafe()->getAsCXXRecordDecl(); |
| 5670 | if (!RD || RD->hasTrivialDefaultConstructor()) |
| 5671 | UnionPathLengths.push_back({PathLength - 1, FD}); |
| 5672 | } |
| 5673 | |
| 5674 | E = ME->getBase(); |
| 5675 | --PathLength; |
| 5676 | assert(declaresSameEntity(FD,((declaresSameEntity(FD, LHS.Designator.Entries[PathLength] . getAsBaseOrMember().getPointer())) ? static_cast<void> ( 0) : __assert_fail ("declaresSameEntity(FD, LHS.Designator.Entries[PathLength] .getAsBaseOrMember().getPointer())" , "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 5678, __PRETTY_FUNCTION__)) |
| 5677 | LHS.Designator.Entries[PathLength]((declaresSameEntity(FD, LHS.Designator.Entries[PathLength] . getAsBaseOrMember().getPointer())) ? static_cast<void> ( 0) : __assert_fail ("declaresSameEntity(FD, LHS.Designator.Entries[PathLength] .getAsBaseOrMember().getPointer())" , "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 5678, __PRETTY_FUNCTION__)) |
| 5678 | .getAsBaseOrMember().getPointer()))((declaresSameEntity(FD, LHS.Designator.Entries[PathLength] . getAsBaseOrMember().getPointer())) ? static_cast<void> ( 0) : __assert_fail ("declaresSameEntity(FD, LHS.Designator.Entries[PathLength] .getAsBaseOrMember().getPointer())" , "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 5678, __PRETTY_FUNCTION__)); |
| 5679 | |
| 5680 | // -- If E is of the form A[B] and is interpreted as a built-in array |
| 5681 | // subscripting operator, S(E) is [S(the array operand, if any)]. |
| 5682 | } else if (auto *ASE = dyn_cast<ArraySubscriptExpr>(E)) { |
| 5683 | // Step over an ArrayToPointerDecay implicit cast. |
| 5684 | auto *Base = ASE->getBase()->IgnoreImplicit(); |
| 5685 | if (!Base->getType()->isArrayType()) |
| 5686 | break; |
| 5687 | |
| 5688 | E = Base; |
| 5689 | --PathLength; |
| 5690 | |
| 5691 | } else if (auto *ICE = dyn_cast<ImplicitCastExpr>(E)) { |
| 5692 | // Step over a derived-to-base conversion. |
| 5693 | E = ICE->getSubExpr(); |
| 5694 | if (ICE->getCastKind() == CK_NoOp) |
| 5695 | continue; |
| 5696 | if (ICE->getCastKind() != CK_DerivedToBase && |
| 5697 | ICE->getCastKind() != CK_UncheckedDerivedToBase) |
| 5698 | break; |
| 5699 | // Walk path backwards as we walk up from the base to the derived class. |
| 5700 | for (const CXXBaseSpecifier *Elt : llvm::reverse(ICE->path())) { |
| 5701 | --PathLength; |
| 5702 | (void)Elt; |
| 5703 | assert(declaresSameEntity(Elt->getType()->getAsCXXRecordDecl(),((declaresSameEntity(Elt->getType()->getAsCXXRecordDecl (), LHS.Designator.Entries[PathLength] .getAsBaseOrMember().getPointer ())) ? static_cast<void> (0) : __assert_fail ("declaresSameEntity(Elt->getType()->getAsCXXRecordDecl(), LHS.Designator.Entries[PathLength] .getAsBaseOrMember().getPointer())" , "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 5705, __PRETTY_FUNCTION__)) |
| 5704 | LHS.Designator.Entries[PathLength]((declaresSameEntity(Elt->getType()->getAsCXXRecordDecl (), LHS.Designator.Entries[PathLength] .getAsBaseOrMember().getPointer ())) ? static_cast<void> (0) : __assert_fail ("declaresSameEntity(Elt->getType()->getAsCXXRecordDecl(), LHS.Designator.Entries[PathLength] .getAsBaseOrMember().getPointer())" , "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 5705, __PRETTY_FUNCTION__)) |
| 5705 | .getAsBaseOrMember().getPointer()))((declaresSameEntity(Elt->getType()->getAsCXXRecordDecl (), LHS.Designator.Entries[PathLength] .getAsBaseOrMember().getPointer ())) ? static_cast<void> (0) : __assert_fail ("declaresSameEntity(Elt->getType()->getAsCXXRecordDecl(), LHS.Designator.Entries[PathLength] .getAsBaseOrMember().getPointer())" , "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 5705, __PRETTY_FUNCTION__)); |
| 5706 | } |
| 5707 | |
| 5708 | // -- Otherwise, S(E) is empty. |
| 5709 | } else { |
| 5710 | break; |
| 5711 | } |
| 5712 | } |
| 5713 | |
| 5714 | // Common case: no unions' lifetimes are started. |
| 5715 | if (UnionPathLengths.empty()) |
| 5716 | return true; |
| 5717 | |
| 5718 | // if modification of X [would access an inactive union member], an object |
| 5719 | // of the type of X is implicitly created |
| 5720 | CompleteObject Obj = |
| 5721 | findCompleteObject(Info, LHSExpr, AK_Assign, LHS, LHSExpr->getType()); |
| 5722 | if (!Obj) |
| 5723 | return false; |
| 5724 | for (std::pair<unsigned, const FieldDecl *> LengthAndField : |
| 5725 | llvm::reverse(UnionPathLengths)) { |
| 5726 | // Form a designator for the union object. |
| 5727 | SubobjectDesignator D = LHS.Designator; |
| 5728 | D.truncate(Info.Ctx, LHS.Base, LengthAndField.first); |
| 5729 | |
| 5730 | bool DuringInit = Info.isEvaluatingCtorDtor(LHS.Base, D.Entries) == |
| 5731 | ConstructionPhase::AfterBases; |
| 5732 | StartLifetimeOfUnionMemberHandler StartLifetime{ |
| 5733 | Info, LHSExpr, LengthAndField.second, DuringInit}; |
| 5734 | if (!findSubobject(Info, LHSExpr, Obj, D, StartLifetime)) |
| 5735 | return false; |
| 5736 | } |
| 5737 | |
| 5738 | return true; |
| 5739 | } |
| 5740 | |
| 5741 | namespace { |
| 5742 | typedef SmallVector<APValue, 8> ArgVector; |
| 5743 | } |
| 5744 | |
| 5745 | /// EvaluateArgs - Evaluate the arguments to a function call. |
| 5746 | static bool EvaluateArgs(ArrayRef<const Expr *> Args, ArgVector &ArgValues, |
| 5747 | EvalInfo &Info, const FunctionDecl *Callee) { |
| 5748 | bool Success = true; |
| 5749 | llvm::SmallBitVector ForbiddenNullArgs; |
| 5750 | if (Callee->hasAttr<NonNullAttr>()) { |
| 5751 | ForbiddenNullArgs.resize(Args.size()); |
| 5752 | for (const auto *Attr : Callee->specific_attrs<NonNullAttr>()) { |
| 5753 | if (!Attr->args_size()) { |
| 5754 | ForbiddenNullArgs.set(); |
| 5755 | break; |
| 5756 | } else |
| 5757 | for (auto Idx : Attr->args()) { |
| 5758 | unsigned ASTIdx = Idx.getASTIndex(); |
| 5759 | if (ASTIdx >= Args.size()) |
| 5760 | continue; |
| 5761 | ForbiddenNullArgs[ASTIdx] = 1; |
| 5762 | } |
| 5763 | } |
| 5764 | } |
| 5765 | // FIXME: This is the wrong evaluation order for an assignment operator |
| 5766 | // called via operator syntax. |
| 5767 | for (unsigned Idx = 0; Idx < Args.size(); Idx++) { |
| 5768 | if (!Evaluate(ArgValues[Idx], Info, Args[Idx])) { |
| 5769 | // If we're checking for a potential constant expression, evaluate all |
| 5770 | // initializers even if some of them fail. |
| 5771 | if (!Info.noteFailure()) |
| 5772 | return false; |
| 5773 | Success = false; |
| 5774 | } else if (!ForbiddenNullArgs.empty() && |
| 5775 | ForbiddenNullArgs[Idx] && |
| 5776 | ArgValues[Idx].isLValue() && |
| 5777 | ArgValues[Idx].isNullPointer()) { |
| 5778 | Info.CCEDiag(Args[Idx], diag::note_non_null_attribute_failed); |
| 5779 | if (!Info.noteFailure()) |
| 5780 | return false; |
| 5781 | Success = false; |
| 5782 | } |
| 5783 | } |
| 5784 | return Success; |
| 5785 | } |
| 5786 | |
| 5787 | /// Evaluate a function call. |
| 5788 | static bool HandleFunctionCall(SourceLocation CallLoc, |
| 5789 | const FunctionDecl *Callee, const LValue *This, |
| 5790 | ArrayRef<const Expr*> Args, const Stmt *Body, |
| 5791 | EvalInfo &Info, APValue &Result, |
| 5792 | const LValue *ResultSlot) { |
| 5793 | ArgVector ArgValues(Args.size()); |
| 5794 | if (!EvaluateArgs(Args, ArgValues, Info, Callee)) |
| 5795 | return false; |
| 5796 | |
| 5797 | if (!Info.CheckCallLimit(CallLoc)) |
| 5798 | return false; |
| 5799 | |
| 5800 | CallStackFrame Frame(Info, CallLoc, Callee, This, ArgValues.data()); |
| 5801 | |
| 5802 | // For a trivial copy or move assignment, perform an APValue copy. This is |
| 5803 | // essential for unions, where the operations performed by the assignment |
| 5804 | // operator cannot be represented as statements. |
| 5805 | // |
| 5806 | // Skip this for non-union classes with no fields; in that case, the defaulted |
| 5807 | // copy/move does not actually read the object. |
| 5808 | const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(Callee); |
| 5809 | if (MD && MD->isDefaulted() && |
| 5810 | (MD->getParent()->isUnion() || |
| 5811 | (MD->isTrivial() && |
| 5812 | isReadByLvalueToRvalueConversion(MD->getParent())))) { |
| 5813 | assert(This &&((This && (MD->isCopyAssignmentOperator() || MD-> isMoveAssignmentOperator())) ? static_cast<void> (0) : __assert_fail ("This && (MD->isCopyAssignmentOperator() || MD->isMoveAssignmentOperator())" , "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 5814, __PRETTY_FUNCTION__)) |
| 5814 | (MD->isCopyAssignmentOperator() || MD->isMoveAssignmentOperator()))((This && (MD->isCopyAssignmentOperator() || MD-> isMoveAssignmentOperator())) ? static_cast<void> (0) : __assert_fail ("This && (MD->isCopyAssignmentOperator() || MD->isMoveAssignmentOperator())" , "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/clang/lib/AST/ExprConstant.cpp" , 5814, __PRETTY_FUNCTION__)); |
| 5815 | LValue RHS; |
| 5816 | RHS.setFrom(Info.Ctx, ArgValues[0]); |
| 5817 | APValue RHSValue; |
| 5818 | if (!handleLValueToRValueConversion(Info, Args[0], Args[0]->getType(), RHS, |
| 5819 | RHSValue, MD->getParent()->isUnion())) |
| 5820 | return false; |
| 5821 | if (Info.getLangOpts().CPlusPlus20 && MD->isTrivial() && |
| 5822 | !HandleUnionActiveMemberChange(Info, Args[0], *This)) |
| 5823 | return false; |
| 5824 | if (!handleAssignment(Info, Args[0], *This, MD->getThisType(), |
| 5825 | RHSValue)) |
| 5826 | return false; |
| 5827 | This->moveInto(Result); |
| 5828 | return true; |
| 5829 | } else if (MD && isLambdaCallOperator(MD)) { |
| 5830 | // We're in a lambda; determine the lambda capture field maps unless we're |
| 5831 | // just constexpr checking a lambda's call operator. constexpr checking is |
| 5832 | // done before the captures have been added to the closure object (unless |
| 5833 | // we're inferring constexpr-ness), so we don't have access to them in this |
| 5834 | // case. But since we don't need the captures to constexpr check, we can |
| 5835 | // just ignore them. |
| 5836 | if (!Info.checkingPotentialConstantExpression()) |
| 5837 | MD->getParent()->getCaptureFields(Frame.LambdaCaptureFields, |
| 5838 | Frame.LambdaThisCaptureField); |
| 5839 | } |
| 5840 | |
| 5841 | StmtResult Ret = {Result, ResultSlot}; |
| 5842 | EvalStmtResult ESR = EvaluateStmt(Ret, Info, Body); |
| 5843 | if (ESR == ESR_Succeeded) { |
| 5844 | if (Callee->getReturnType()->isVoidType()) |
| 5845 | return true; |
| 5846 | Info.FFDiag(Callee->getEndLoc(), diag::note_constexpr_no_return); |
| 5847 | } |
| 5848 | return ESR == ESR_Returned; |
| 5849 | } |
| 5850 | |
| 5851 | /// Evaluate a constructor call. |
| 5852 | static bool HandleConstructorCall(const Expr *E, const LValue &This, |
| 5853 | APValue *ArgValues, |
| 5854 | const CXXConstructorDecl *Definition, |
| 5855 | EvalInfo &Info, APValue &Result) { |
| 5856 | SourceLocation CallLoc = E->getExprLoc(); |
| 5857 | if (!Info.CheckCallLimit(CallLoc)) |
| 5858 | return false; |
| 5859 | |
| 5860 | const CXXRecordDecl *RD = Definition->getParent(); |
| 5861 | if (RD->getNumVBases()) { |
| 5862 | Info.FFDiag(CallLoc, diag::note_constexpr_virtual_base) << RD; |
| 5863 | return false; |
| 5864 | } |
| 5865 | |
| 5866 | EvalInfo::EvaluatingConstructorRAII EvalObj( |
| 5867 | Info, |
| 5868 | ObjectUnderConstruction{This.getLValueBase(), This.Designator.Entries}, |
| 5869 | RD->getNumBases()); |
| 5870 | CallStackFrame Frame(Info, CallLoc, Definition, &This, ArgValues); |
| 5871 | |
| 5872 | // FIXME: Creating an APValue just to hold a nonexistent return value is |
| 5873 | // wasteful. |
| 5874 | APValue RetVal; |
| 5875 | StmtResult Ret = {RetVal, nullptr}; |
| 5876 | |
| 5877 | // If it's a delegating constructor, delegate. |
| 5878 | if (Definition->isDelegatingConstructor()) { |
| 5879 | CXXConstructorDecl::init_const_iterator I = Definition->init_begin(); |
| 5880 | { |
| 5881 | FullExpressionRAII InitScope(Info); |
| 5882 | if (!EvaluateInPlace(Result, Info, This, (*I)->getInit()) || |
| 5883 | !InitScope.destroy()) |
| 5884 | return false; |
| 5885 | } |
| 5886 | return EvaluateStmt(Ret, Info, Definition->getBody()) != ESR_Failed; |
| 5887 | } |
| 5888 | |
| 5889 | // For a trivial copy or move constructor, perform an APValue copy. This is |
| 5890 | // essential for unions (or classes with anonymous union members), where the |
| 5891 | // operations performed by the constructor cannot be represented by |
| 5892 | // ctor-initializers. |
| 5893 | // |
| 5894 | // Skip this for empty non-union classes; we should not perform an |
| 5895 | // lvalue-to-rvalue conversion on them because their copy constructor does not |
| 5896 | // actually read them. |
| 5897 | if (Definition->isDefaulted() && Definition->isCopyOrMoveConstructor() && |
| 5898 | (Definition->getParent()->isUnion() || |
| 5899 | (Definition->isTrivial() && |
| 5900 | isReadByLvalueToRvalueConversion(Definition->getParent())))) { |
| 5901 | LValue RHS; |
| 5902 | RHS.setFrom(Info.Ctx, ArgValues[0]); |
| 5903 | return handleLValueToRValueConversion( |
| 5904 | Info, E, Definition->getParamDecl(0)->getType().getNonReferenceType(), |
| 5905 |