1 //===--- CGExprCXX.cpp - Emit LLVM Code for C++ expressions ---------------===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 // 10 // This contains code dealing with code generation of C++ expressions 11 // 12 //===----------------------------------------------------------------------===// 13 14 #include "CodeGenFunction.h" 15 #include "CGCUDARuntime.h" 16 #include "CGCXXABI.h" 17 #include "CGDebugInfo.h" 18 #include "CGObjCRuntime.h" 19 #include "clang/CodeGen/CGFunctionInfo.h" 20 #include "clang/Frontend/CodeGenOptions.h" 21 #include "llvm/IR/CallSite.h" 22 #include "llvm/IR/Intrinsics.h" 23 24 using namespace clang; 25 using namespace CodeGen; 26 27 static RequiredArgs commonEmitCXXMemberOrOperatorCall( 28 CodeGenFunction &CGF, const CXXMethodDecl *MD, llvm::Value *Callee, 29 ReturnValueSlot ReturnValue, llvm::Value *This, llvm::Value *ImplicitParam, 30 QualType ImplicitParamTy, const CallExpr *CE, CallArgList &Args) { 31 assert(CE == nullptr || isa<CXXMemberCallExpr>(CE) || 32 isa<CXXOperatorCallExpr>(CE)); 33 assert(MD->isInstance() && 34 "Trying to emit a member or operator call expr on a static method!"); 35 36 // C++11 [class.mfct.non-static]p2: 37 // If a non-static member function of a class X is called for an object that 38 // is not of type X, or of a type derived from X, the behavior is undefined. 39 SourceLocation CallLoc; 40 if (CE) 41 CallLoc = CE->getExprLoc(); 42 CGF.EmitTypeCheck( 43 isa<CXXConstructorDecl>(MD) ? CodeGenFunction::TCK_ConstructorCall 44 : CodeGenFunction::TCK_MemberCall, 45 CallLoc, This, CGF.getContext().getRecordType(MD->getParent())); 46 47 // Push the this ptr. 48 Args.add(RValue::get(This), MD->getThisType(CGF.getContext())); 49 50 // If there is an implicit parameter (e.g. VTT), emit it. 51 if (ImplicitParam) { 52 Args.add(RValue::get(ImplicitParam), ImplicitParamTy); 53 } 54 55 const FunctionProtoType *FPT = MD->getType()->castAs<FunctionProtoType>(); 56 RequiredArgs required = RequiredArgs::forPrototypePlus(FPT, Args.size()); 57 58 // And the rest of the call args. 59 if (CE) { 60 // Special case: skip first argument of CXXOperatorCall (it is "this"). 61 unsigned ArgsToSkip = isa<CXXOperatorCallExpr>(CE) ? 1 : 0; 62 CGF.EmitCallArgs(Args, FPT, CE->arg_begin() + ArgsToSkip, CE->arg_end(), 63 CE->getDirectCallee()); 64 } else { 65 assert( 66 FPT->getNumParams() == 0 && 67 "No CallExpr specified for function with non-zero number of arguments"); 68 } 69 return required; 70 } 71 72 RValue CodeGenFunction::EmitCXXMemberOrOperatorCall( 73 const CXXMethodDecl *MD, llvm::Value *Callee, ReturnValueSlot ReturnValue, 74 llvm::Value *This, llvm::Value *ImplicitParam, QualType ImplicitParamTy, 75 const CallExpr *CE) { 76 const FunctionProtoType *FPT = MD->getType()->castAs<FunctionProtoType>(); 77 CallArgList Args; 78 RequiredArgs required = commonEmitCXXMemberOrOperatorCall( 79 *this, MD, Callee, ReturnValue, This, ImplicitParam, ImplicitParamTy, CE, 80 Args); 81 return EmitCall(CGM.getTypes().arrangeCXXMethodCall(Args, FPT, required), 82 Callee, ReturnValue, Args, MD); 83 } 84 85 RValue CodeGenFunction::EmitCXXStructorCall( 86 const CXXMethodDecl *MD, llvm::Value *Callee, ReturnValueSlot ReturnValue, 87 llvm::Value *This, llvm::Value *ImplicitParam, QualType ImplicitParamTy, 88 const CallExpr *CE, StructorType Type) { 89 CallArgList Args; 90 commonEmitCXXMemberOrOperatorCall(*this, MD, Callee, ReturnValue, This, 91 ImplicitParam, ImplicitParamTy, CE, Args); 92 return EmitCall(CGM.getTypes().arrangeCXXStructorDeclaration(MD, Type), 93 Callee, ReturnValue, Args, MD); 94 } 95 96 static CXXRecordDecl *getCXXRecord(const Expr *E) { 97 QualType T = E->getType(); 98 if (const PointerType *PTy = T->getAs<PointerType>()) 99 T = PTy->getPointeeType(); 100 const RecordType *Ty = T->castAs<RecordType>(); 101 return cast<CXXRecordDecl>(Ty->getDecl()); 102 } 103 104 // Note: This function also emit constructor calls to support a MSVC 105 // extensions allowing explicit constructor function call. 106 RValue CodeGenFunction::EmitCXXMemberCallExpr(const CXXMemberCallExpr *CE, 107 ReturnValueSlot ReturnValue) { 108 const Expr *callee = CE->getCallee()->IgnoreParens(); 109 110 if (isa<BinaryOperator>(callee)) 111 return EmitCXXMemberPointerCallExpr(CE, ReturnValue); 112 113 const MemberExpr *ME = cast<MemberExpr>(callee); 114 const CXXMethodDecl *MD = cast<CXXMethodDecl>(ME->getMemberDecl()); 115 116 if (MD->isStatic()) { 117 // The method is static, emit it as we would a regular call. 118 llvm::Value *Callee = CGM.GetAddrOfFunction(MD); 119 return EmitCall(getContext().getPointerType(MD->getType()), Callee, CE, 120 ReturnValue); 121 } 122 123 bool HasQualifier = ME->hasQualifier(); 124 NestedNameSpecifier *Qualifier = HasQualifier ? ME->getQualifier() : nullptr; 125 bool IsArrow = ME->isArrow(); 126 const Expr *Base = ME->getBase(); 127 128 return EmitCXXMemberOrOperatorMemberCallExpr( 129 CE, MD, ReturnValue, HasQualifier, Qualifier, IsArrow, Base); 130 } 131 132 RValue CodeGenFunction::EmitCXXMemberOrOperatorMemberCallExpr( 133 const CallExpr *CE, const CXXMethodDecl *MD, ReturnValueSlot ReturnValue, 134 bool HasQualifier, NestedNameSpecifier *Qualifier, bool IsArrow, 135 const Expr *Base) { 136 assert(isa<CXXMemberCallExpr>(CE) || isa<CXXOperatorCallExpr>(CE)); 137 138 // Compute the object pointer. 139 bool CanUseVirtualCall = MD->isVirtual() && !HasQualifier; 140 141 const CXXMethodDecl *DevirtualizedMethod = nullptr; 142 if (CanUseVirtualCall && CanDevirtualizeMemberFunctionCall(Base, MD)) { 143 const CXXRecordDecl *BestDynamicDecl = Base->getBestDynamicClassType(); 144 DevirtualizedMethod = MD->getCorrespondingMethodInClass(BestDynamicDecl); 145 assert(DevirtualizedMethod); 146 const CXXRecordDecl *DevirtualizedClass = DevirtualizedMethod->getParent(); 147 const Expr *Inner = Base->ignoreParenBaseCasts(); 148 if (DevirtualizedMethod->getReturnType().getCanonicalType() != 149 MD->getReturnType().getCanonicalType()) 150 // If the return types are not the same, this might be a case where more 151 // code needs to run to compensate for it. For example, the derived 152 // method might return a type that inherits form from the return 153 // type of MD and has a prefix. 154 // For now we just avoid devirtualizing these covariant cases. 155 DevirtualizedMethod = nullptr; 156 else if (getCXXRecord(Inner) == DevirtualizedClass) 157 // If the class of the Inner expression is where the dynamic method 158 // is defined, build the this pointer from it. 159 Base = Inner; 160 else if (getCXXRecord(Base) != DevirtualizedClass) { 161 // If the method is defined in a class that is not the best dynamic 162 // one or the one of the full expression, we would have to build 163 // a derived-to-base cast to compute the correct this pointer, but 164 // we don't have support for that yet, so do a virtual call. 165 DevirtualizedMethod = nullptr; 166 } 167 } 168 169 llvm::Value *This; 170 if (IsArrow) 171 This = EmitScalarExpr(Base); 172 else 173 This = EmitLValue(Base).getAddress(); 174 175 176 if (MD->isTrivial()) { 177 if (isa<CXXDestructorDecl>(MD)) return RValue::get(nullptr); 178 if (isa<CXXConstructorDecl>(MD) && 179 cast<CXXConstructorDecl>(MD)->isDefaultConstructor()) 180 return RValue::get(nullptr); 181 182 if (!MD->getParent()->mayInsertExtraPadding()) { 183 if (MD->isCopyAssignmentOperator() || MD->isMoveAssignmentOperator()) { 184 // We don't like to generate the trivial copy/move assignment operator 185 // when it isn't necessary; just produce the proper effect here. 186 // Special case: skip first argument of CXXOperatorCall (it is "this"). 187 unsigned ArgsToSkip = isa<CXXOperatorCallExpr>(CE) ? 1 : 0; 188 llvm::Value *RHS = 189 EmitLValue(*(CE->arg_begin() + ArgsToSkip)).getAddress(); 190 EmitAggregateAssign(This, RHS, CE->getType()); 191 return RValue::get(This); 192 } 193 194 if (isa<CXXConstructorDecl>(MD) && 195 cast<CXXConstructorDecl>(MD)->isCopyOrMoveConstructor()) { 196 // Trivial move and copy ctor are the same. 197 assert(CE->getNumArgs() == 1 && "unexpected argcount for trivial ctor"); 198 llvm::Value *RHS = EmitLValue(*CE->arg_begin()).getAddress(); 199 EmitAggregateCopy(This, RHS, CE->arg_begin()->getType()); 200 return RValue::get(This); 201 } 202 llvm_unreachable("unknown trivial member function"); 203 } 204 } 205 206 // Compute the function type we're calling. 207 const CXXMethodDecl *CalleeDecl = 208 DevirtualizedMethod ? DevirtualizedMethod : MD; 209 const CGFunctionInfo *FInfo = nullptr; 210 if (const auto *Dtor = dyn_cast<CXXDestructorDecl>(CalleeDecl)) 211 FInfo = &CGM.getTypes().arrangeCXXStructorDeclaration( 212 Dtor, StructorType::Complete); 213 else if (const auto *Ctor = dyn_cast<CXXConstructorDecl>(CalleeDecl)) 214 FInfo = &CGM.getTypes().arrangeCXXStructorDeclaration( 215 Ctor, StructorType::Complete); 216 else 217 FInfo = &CGM.getTypes().arrangeCXXMethodDeclaration(CalleeDecl); 218 219 llvm::FunctionType *Ty = CGM.getTypes().GetFunctionType(*FInfo); 220 221 // C++ [class.virtual]p12: 222 // Explicit qualification with the scope operator (5.1) suppresses the 223 // virtual call mechanism. 224 // 225 // We also don't emit a virtual call if the base expression has a record type 226 // because then we know what the type is. 227 bool UseVirtualCall = CanUseVirtualCall && !DevirtualizedMethod; 228 llvm::Value *Callee; 229 230 if (const CXXDestructorDecl *Dtor = dyn_cast<CXXDestructorDecl>(MD)) { 231 assert(CE->arg_begin() == CE->arg_end() && 232 "Destructor shouldn't have explicit parameters"); 233 assert(ReturnValue.isNull() && "Destructor shouldn't have return value"); 234 if (UseVirtualCall) { 235 CGM.getCXXABI().EmitVirtualDestructorCall( 236 *this, Dtor, Dtor_Complete, This, cast<CXXMemberCallExpr>(CE)); 237 } else { 238 if (getLangOpts().AppleKext && MD->isVirtual() && HasQualifier) 239 Callee = BuildAppleKextVirtualCall(MD, Qualifier, Ty); 240 else if (!DevirtualizedMethod) 241 Callee = 242 CGM.getAddrOfCXXStructor(Dtor, StructorType::Complete, FInfo, Ty); 243 else { 244 const CXXDestructorDecl *DDtor = 245 cast<CXXDestructorDecl>(DevirtualizedMethod); 246 Callee = CGM.GetAddrOfFunction(GlobalDecl(DDtor, Dtor_Complete), Ty); 247 } 248 EmitCXXMemberOrOperatorCall(MD, Callee, ReturnValue, This, 249 /*ImplicitParam=*/nullptr, QualType(), CE); 250 } 251 return RValue::get(nullptr); 252 } 253 254 if (const CXXConstructorDecl *Ctor = dyn_cast<CXXConstructorDecl>(MD)) { 255 Callee = CGM.GetAddrOfFunction(GlobalDecl(Ctor, Ctor_Complete), Ty); 256 } else if (UseVirtualCall) { 257 Callee = CGM.getCXXABI().getVirtualFunctionPointer(*this, MD, This, Ty); 258 } else { 259 if (SanOpts.has(SanitizerKind::CFINVCall) && 260 MD->getParent()->isDynamicClass()) { 261 llvm::Value *VTable = GetVTablePtr(This, Int8PtrTy); 262 EmitVTablePtrCheckForCall(MD, VTable); 263 } 264 265 if (getLangOpts().AppleKext && MD->isVirtual() && HasQualifier) 266 Callee = BuildAppleKextVirtualCall(MD, Qualifier, Ty); 267 else if (!DevirtualizedMethod) 268 Callee = CGM.GetAddrOfFunction(MD, Ty); 269 else { 270 Callee = CGM.GetAddrOfFunction(DevirtualizedMethod, Ty); 271 } 272 } 273 274 if (MD->isVirtual()) { 275 This = CGM.getCXXABI().adjustThisArgumentForVirtualFunctionCall( 276 *this, MD, This, UseVirtualCall); 277 } 278 279 return EmitCXXMemberOrOperatorCall(MD, Callee, ReturnValue, This, 280 /*ImplicitParam=*/nullptr, QualType(), CE); 281 } 282 283 RValue 284 CodeGenFunction::EmitCXXMemberPointerCallExpr(const CXXMemberCallExpr *E, 285 ReturnValueSlot ReturnValue) { 286 const BinaryOperator *BO = 287 cast<BinaryOperator>(E->getCallee()->IgnoreParens()); 288 const Expr *BaseExpr = BO->getLHS(); 289 const Expr *MemFnExpr = BO->getRHS(); 290 291 const MemberPointerType *MPT = 292 MemFnExpr->getType()->castAs<MemberPointerType>(); 293 294 const FunctionProtoType *FPT = 295 MPT->getPointeeType()->castAs<FunctionProtoType>(); 296 const CXXRecordDecl *RD = 297 cast<CXXRecordDecl>(MPT->getClass()->getAs<RecordType>()->getDecl()); 298 299 // Get the member function pointer. 300 llvm::Value *MemFnPtr = EmitScalarExpr(MemFnExpr); 301 302 // Emit the 'this' pointer. 303 llvm::Value *This; 304 305 if (BO->getOpcode() == BO_PtrMemI) 306 This = EmitScalarExpr(BaseExpr); 307 else 308 This = EmitLValue(BaseExpr).getAddress(); 309 310 EmitTypeCheck(TCK_MemberCall, E->getExprLoc(), This, 311 QualType(MPT->getClass(), 0)); 312 313 // Ask the ABI to load the callee. Note that This is modified. 314 llvm::Value *Callee = 315 CGM.getCXXABI().EmitLoadOfMemberFunctionPointer(*this, BO, This, MemFnPtr, MPT); 316 317 CallArgList Args; 318 319 QualType ThisType = 320 getContext().getPointerType(getContext().getTagDeclType(RD)); 321 322 // Push the this ptr. 323 Args.add(RValue::get(This), ThisType); 324 325 RequiredArgs required = RequiredArgs::forPrototypePlus(FPT, 1); 326 327 // And the rest of the call args 328 EmitCallArgs(Args, FPT, E->arg_begin(), E->arg_end(), E->getDirectCallee()); 329 return EmitCall(CGM.getTypes().arrangeCXXMethodCall(Args, FPT, required), 330 Callee, ReturnValue, Args); 331 } 332 333 RValue 334 CodeGenFunction::EmitCXXOperatorMemberCallExpr(const CXXOperatorCallExpr *E, 335 const CXXMethodDecl *MD, 336 ReturnValueSlot ReturnValue) { 337 assert(MD->isInstance() && 338 "Trying to emit a member call expr on a static method!"); 339 return EmitCXXMemberOrOperatorMemberCallExpr( 340 E, MD, ReturnValue, /*HasQualifier=*/false, /*Qualifier=*/nullptr, 341 /*IsArrow=*/false, E->getArg(0)); 342 } 343 344 RValue CodeGenFunction::EmitCUDAKernelCallExpr(const CUDAKernelCallExpr *E, 345 ReturnValueSlot ReturnValue) { 346 return CGM.getCUDARuntime().EmitCUDAKernelCallExpr(*this, E, ReturnValue); 347 } 348 349 static void EmitNullBaseClassInitialization(CodeGenFunction &CGF, 350 llvm::Value *DestPtr, 351 const CXXRecordDecl *Base) { 352 if (Base->isEmpty()) 353 return; 354 355 DestPtr = CGF.EmitCastToVoidPtr(DestPtr); 356 357 const ASTRecordLayout &Layout = CGF.getContext().getASTRecordLayout(Base); 358 CharUnits Size = Layout.getNonVirtualSize(); 359 CharUnits Align = Layout.getNonVirtualAlignment(); 360 361 llvm::Value *SizeVal = CGF.CGM.getSize(Size); 362 363 // If the type contains a pointer to data member we can't memset it to zero. 364 // Instead, create a null constant and copy it to the destination. 365 // TODO: there are other patterns besides zero that we can usefully memset, 366 // like -1, which happens to be the pattern used by member-pointers. 367 // TODO: isZeroInitializable can be over-conservative in the case where a 368 // virtual base contains a member pointer. 369 if (!CGF.CGM.getTypes().isZeroInitializable(Base)) { 370 llvm::Constant *NullConstant = CGF.CGM.EmitNullConstantForBase(Base); 371 372 llvm::GlobalVariable *NullVariable = 373 new llvm::GlobalVariable(CGF.CGM.getModule(), NullConstant->getType(), 374 /*isConstant=*/true, 375 llvm::GlobalVariable::PrivateLinkage, 376 NullConstant, Twine()); 377 NullVariable->setAlignment(Align.getQuantity()); 378 llvm::Value *SrcPtr = CGF.EmitCastToVoidPtr(NullVariable); 379 380 // Get and call the appropriate llvm.memcpy overload. 381 CGF.Builder.CreateMemCpy(DestPtr, SrcPtr, SizeVal, Align.getQuantity()); 382 return; 383 } 384 385 // Otherwise, just memset the whole thing to zero. This is legal 386 // because in LLVM, all default initializers (other than the ones we just 387 // handled above) are guaranteed to have a bit pattern of all zeros. 388 CGF.Builder.CreateMemSet(DestPtr, CGF.Builder.getInt8(0), SizeVal, 389 Align.getQuantity()); 390 } 391 392 void 393 CodeGenFunction::EmitCXXConstructExpr(const CXXConstructExpr *E, 394 AggValueSlot Dest) { 395 assert(!Dest.isIgnored() && "Must have a destination!"); 396 const CXXConstructorDecl *CD = E->getConstructor(); 397 398 // If we require zero initialization before (or instead of) calling the 399 // constructor, as can be the case with a non-user-provided default 400 // constructor, emit the zero initialization now, unless destination is 401 // already zeroed. 402 if (E->requiresZeroInitialization() && !Dest.isZeroed()) { 403 switch (E->getConstructionKind()) { 404 case CXXConstructExpr::CK_Delegating: 405 case CXXConstructExpr::CK_Complete: 406 EmitNullInitialization(Dest.getAddr(), E->getType()); 407 break; 408 case CXXConstructExpr::CK_VirtualBase: 409 case CXXConstructExpr::CK_NonVirtualBase: 410 EmitNullBaseClassInitialization(*this, Dest.getAddr(), CD->getParent()); 411 break; 412 } 413 } 414 415 // If this is a call to a trivial default constructor, do nothing. 416 if (CD->isTrivial() && CD->isDefaultConstructor()) 417 return; 418 419 // Elide the constructor if we're constructing from a temporary. 420 // The temporary check is required because Sema sets this on NRVO 421 // returns. 422 if (getLangOpts().ElideConstructors && E->isElidable()) { 423 assert(getContext().hasSameUnqualifiedType(E->getType(), 424 E->getArg(0)->getType())); 425 if (E->getArg(0)->isTemporaryObject(getContext(), CD->getParent())) { 426 EmitAggExpr(E->getArg(0), Dest); 427 return; 428 } 429 } 430 431 if (const ConstantArrayType *arrayType 432 = getContext().getAsConstantArrayType(E->getType())) { 433 EmitCXXAggrConstructorCall(CD, arrayType, Dest.getAddr(), E); 434 } else { 435 CXXCtorType Type = Ctor_Complete; 436 bool ForVirtualBase = false; 437 bool Delegating = false; 438 439 switch (E->getConstructionKind()) { 440 case CXXConstructExpr::CK_Delegating: 441 // We should be emitting a constructor; GlobalDecl will assert this 442 Type = CurGD.getCtorType(); 443 Delegating = true; 444 break; 445 446 case CXXConstructExpr::CK_Complete: 447 Type = Ctor_Complete; 448 break; 449 450 case CXXConstructExpr::CK_VirtualBase: 451 ForVirtualBase = true; 452 // fall-through 453 454 case CXXConstructExpr::CK_NonVirtualBase: 455 Type = Ctor_Base; 456 } 457 458 // Call the constructor. 459 EmitCXXConstructorCall(CD, Type, ForVirtualBase, Delegating, Dest.getAddr(), 460 E); 461 } 462 } 463 464 void 465 CodeGenFunction::EmitSynthesizedCXXCopyCtor(llvm::Value *Dest, 466 llvm::Value *Src, 467 const Expr *Exp) { 468 if (const ExprWithCleanups *E = dyn_cast<ExprWithCleanups>(Exp)) 469 Exp = E->getSubExpr(); 470 assert(isa<CXXConstructExpr>(Exp) && 471 "EmitSynthesizedCXXCopyCtor - unknown copy ctor expr"); 472 const CXXConstructExpr* E = cast<CXXConstructExpr>(Exp); 473 const CXXConstructorDecl *CD = E->getConstructor(); 474 RunCleanupsScope Scope(*this); 475 476 // If we require zero initialization before (or instead of) calling the 477 // constructor, as can be the case with a non-user-provided default 478 // constructor, emit the zero initialization now. 479 // FIXME. Do I still need this for a copy ctor synthesis? 480 if (E->requiresZeroInitialization()) 481 EmitNullInitialization(Dest, E->getType()); 482 483 assert(!getContext().getAsConstantArrayType(E->getType()) 484 && "EmitSynthesizedCXXCopyCtor - Copied-in Array"); 485 EmitSynthesizedCXXCopyCtorCall(CD, Dest, Src, E); 486 } 487 488 static CharUnits CalculateCookiePadding(CodeGenFunction &CGF, 489 const CXXNewExpr *E) { 490 if (!E->isArray()) 491 return CharUnits::Zero(); 492 493 // No cookie is required if the operator new[] being used is the 494 // reserved placement operator new[]. 495 if (E->getOperatorNew()->isReservedGlobalPlacementOperator()) 496 return CharUnits::Zero(); 497 498 return CGF.CGM.getCXXABI().GetArrayCookieSize(E); 499 } 500 501 static llvm::Value *EmitCXXNewAllocSize(CodeGenFunction &CGF, 502 const CXXNewExpr *e, 503 unsigned minElements, 504 llvm::Value *&numElements, 505 llvm::Value *&sizeWithoutCookie) { 506 QualType type = e->getAllocatedType(); 507 508 if (!e->isArray()) { 509 CharUnits typeSize = CGF.getContext().getTypeSizeInChars(type); 510 sizeWithoutCookie 511 = llvm::ConstantInt::get(CGF.SizeTy, typeSize.getQuantity()); 512 return sizeWithoutCookie; 513 } 514 515 // The width of size_t. 516 unsigned sizeWidth = CGF.SizeTy->getBitWidth(); 517 518 // Figure out the cookie size. 519 llvm::APInt cookieSize(sizeWidth, 520 CalculateCookiePadding(CGF, e).getQuantity()); 521 522 // Emit the array size expression. 523 // We multiply the size of all dimensions for NumElements. 524 // e.g for 'int[2][3]', ElemType is 'int' and NumElements is 6. 525 numElements = CGF.EmitScalarExpr(e->getArraySize()); 526 assert(isa<llvm::IntegerType>(numElements->getType())); 527 528 // The number of elements can be have an arbitrary integer type; 529 // essentially, we need to multiply it by a constant factor, add a 530 // cookie size, and verify that the result is representable as a 531 // size_t. That's just a gloss, though, and it's wrong in one 532 // important way: if the count is negative, it's an error even if 533 // the cookie size would bring the total size >= 0. 534 bool isSigned 535 = e->getArraySize()->getType()->isSignedIntegerOrEnumerationType(); 536 llvm::IntegerType *numElementsType 537 = cast<llvm::IntegerType>(numElements->getType()); 538 unsigned numElementsWidth = numElementsType->getBitWidth(); 539 540 // Compute the constant factor. 541 llvm::APInt arraySizeMultiplier(sizeWidth, 1); 542 while (const ConstantArrayType *CAT 543 = CGF.getContext().getAsConstantArrayType(type)) { 544 type = CAT->getElementType(); 545 arraySizeMultiplier *= CAT->getSize(); 546 } 547 548 CharUnits typeSize = CGF.getContext().getTypeSizeInChars(type); 549 llvm::APInt typeSizeMultiplier(sizeWidth, typeSize.getQuantity()); 550 typeSizeMultiplier *= arraySizeMultiplier; 551 552 // This will be a size_t. 553 llvm::Value *size; 554 555 // If someone is doing 'new int[42]' there is no need to do a dynamic check. 556 // Don't bloat the -O0 code. 557 if (llvm::ConstantInt *numElementsC = 558 dyn_cast<llvm::ConstantInt>(numElements)) { 559 const llvm::APInt &count = numElementsC->getValue(); 560 561 bool hasAnyOverflow = false; 562 563 // If 'count' was a negative number, it's an overflow. 564 if (isSigned && count.isNegative()) 565 hasAnyOverflow = true; 566 567 // We want to do all this arithmetic in size_t. If numElements is 568 // wider than that, check whether it's already too big, and if so, 569 // overflow. 570 else if (numElementsWidth > sizeWidth && 571 numElementsWidth - sizeWidth > count.countLeadingZeros()) 572 hasAnyOverflow = true; 573 574 // Okay, compute a count at the right width. 575 llvm::APInt adjustedCount = count.zextOrTrunc(sizeWidth); 576 577 // If there is a brace-initializer, we cannot allocate fewer elements than 578 // there are initializers. If we do, that's treated like an overflow. 579 if (adjustedCount.ult(minElements)) 580 hasAnyOverflow = true; 581 582 // Scale numElements by that. This might overflow, but we don't 583 // care because it only overflows if allocationSize does, too, and 584 // if that overflows then we shouldn't use this. 585 numElements = llvm::ConstantInt::get(CGF.SizeTy, 586 adjustedCount * arraySizeMultiplier); 587 588 // Compute the size before cookie, and track whether it overflowed. 589 bool overflow; 590 llvm::APInt allocationSize 591 = adjustedCount.umul_ov(typeSizeMultiplier, overflow); 592 hasAnyOverflow |= overflow; 593 594 // Add in the cookie, and check whether it's overflowed. 595 if (cookieSize != 0) { 596 // Save the current size without a cookie. This shouldn't be 597 // used if there was overflow. 598 sizeWithoutCookie = llvm::ConstantInt::get(CGF.SizeTy, allocationSize); 599 600 allocationSize = allocationSize.uadd_ov(cookieSize, overflow); 601 hasAnyOverflow |= overflow; 602 } 603 604 // On overflow, produce a -1 so operator new will fail. 605 if (hasAnyOverflow) { 606 size = llvm::Constant::getAllOnesValue(CGF.SizeTy); 607 } else { 608 size = llvm::ConstantInt::get(CGF.SizeTy, allocationSize); 609 } 610 611 // Otherwise, we might need to use the overflow intrinsics. 612 } else { 613 // There are up to five conditions we need to test for: 614 // 1) if isSigned, we need to check whether numElements is negative; 615 // 2) if numElementsWidth > sizeWidth, we need to check whether 616 // numElements is larger than something representable in size_t; 617 // 3) if minElements > 0, we need to check whether numElements is smaller 618 // than that. 619 // 4) we need to compute 620 // sizeWithoutCookie := numElements * typeSizeMultiplier 621 // and check whether it overflows; and 622 // 5) if we need a cookie, we need to compute 623 // size := sizeWithoutCookie + cookieSize 624 // and check whether it overflows. 625 626 llvm::Value *hasOverflow = nullptr; 627 628 // If numElementsWidth > sizeWidth, then one way or another, we're 629 // going to have to do a comparison for (2), and this happens to 630 // take care of (1), too. 631 if (numElementsWidth > sizeWidth) { 632 llvm::APInt threshold(numElementsWidth, 1); 633 threshold <<= sizeWidth; 634 635 llvm::Value *thresholdV 636 = llvm::ConstantInt::get(numElementsType, threshold); 637 638 hasOverflow = CGF.Builder.CreateICmpUGE(numElements, thresholdV); 639 numElements = CGF.Builder.CreateTrunc(numElements, CGF.SizeTy); 640 641 // Otherwise, if we're signed, we want to sext up to size_t. 642 } else if (isSigned) { 643 if (numElementsWidth < sizeWidth) 644 numElements = CGF.Builder.CreateSExt(numElements, CGF.SizeTy); 645 646 // If there's a non-1 type size multiplier, then we can do the 647 // signedness check at the same time as we do the multiply 648 // because a negative number times anything will cause an 649 // unsigned overflow. Otherwise, we have to do it here. But at least 650 // in this case, we can subsume the >= minElements check. 651 if (typeSizeMultiplier == 1) 652 hasOverflow = CGF.Builder.CreateICmpSLT(numElements, 653 llvm::ConstantInt::get(CGF.SizeTy, minElements)); 654 655 // Otherwise, zext up to size_t if necessary. 656 } else if (numElementsWidth < sizeWidth) { 657 numElements = CGF.Builder.CreateZExt(numElements, CGF.SizeTy); 658 } 659 660 assert(numElements->getType() == CGF.SizeTy); 661 662 if (minElements) { 663 // Don't allow allocation of fewer elements than we have initializers. 664 if (!hasOverflow) { 665 hasOverflow = CGF.Builder.CreateICmpULT(numElements, 666 llvm::ConstantInt::get(CGF.SizeTy, minElements)); 667 } else if (numElementsWidth > sizeWidth) { 668 // The other existing overflow subsumes this check. 669 // We do an unsigned comparison, since any signed value < -1 is 670 // taken care of either above or below. 671 hasOverflow = CGF.Builder.CreateOr(hasOverflow, 672 CGF.Builder.CreateICmpULT(numElements, 673 llvm::ConstantInt::get(CGF.SizeTy, minElements))); 674 } 675 } 676 677 size = numElements; 678 679 // Multiply by the type size if necessary. This multiplier 680 // includes all the factors for nested arrays. 681 // 682 // This step also causes numElements to be scaled up by the 683 // nested-array factor if necessary. Overflow on this computation 684 // can be ignored because the result shouldn't be used if 685 // allocation fails. 686 if (typeSizeMultiplier != 1) { 687 llvm::Value *umul_with_overflow 688 = CGF.CGM.getIntrinsic(llvm::Intrinsic::umul_with_overflow, CGF.SizeTy); 689 690 llvm::Value *tsmV = 691 llvm::ConstantInt::get(CGF.SizeTy, typeSizeMultiplier); 692 llvm::Value *result = 693 CGF.Builder.CreateCall2(umul_with_overflow, size, tsmV); 694 695 llvm::Value *overflowed = CGF.Builder.CreateExtractValue(result, 1); 696 if (hasOverflow) 697 hasOverflow = CGF.Builder.CreateOr(hasOverflow, overflowed); 698 else 699 hasOverflow = overflowed; 700 701 size = CGF.Builder.CreateExtractValue(result, 0); 702 703 // Also scale up numElements by the array size multiplier. 704 if (arraySizeMultiplier != 1) { 705 // If the base element type size is 1, then we can re-use the 706 // multiply we just did. 707 if (typeSize.isOne()) { 708 assert(arraySizeMultiplier == typeSizeMultiplier); 709 numElements = size; 710 711 // Otherwise we need a separate multiply. 712 } else { 713 llvm::Value *asmV = 714 llvm::ConstantInt::get(CGF.SizeTy, arraySizeMultiplier); 715 numElements = CGF.Builder.CreateMul(numElements, asmV); 716 } 717 } 718 } else { 719 // numElements doesn't need to be scaled. 720 assert(arraySizeMultiplier == 1); 721 } 722 723 // Add in the cookie size if necessary. 724 if (cookieSize != 0) { 725 sizeWithoutCookie = size; 726 727 llvm::Value *uadd_with_overflow 728 = CGF.CGM.getIntrinsic(llvm::Intrinsic::uadd_with_overflow, CGF.SizeTy); 729 730 llvm::Value *cookieSizeV = llvm::ConstantInt::get(CGF.SizeTy, cookieSize); 731 llvm::Value *result = 732 CGF.Builder.CreateCall2(uadd_with_overflow, size, cookieSizeV); 733 734 llvm::Value *overflowed = CGF.Builder.CreateExtractValue(result, 1); 735 if (hasOverflow) 736 hasOverflow = CGF.Builder.CreateOr(hasOverflow, overflowed); 737 else 738 hasOverflow = overflowed; 739 740 size = CGF.Builder.CreateExtractValue(result, 0); 741 } 742 743 // If we had any possibility of dynamic overflow, make a select to 744 // overwrite 'size' with an all-ones value, which should cause 745 // operator new to throw. 746 if (hasOverflow) 747 size = CGF.Builder.CreateSelect(hasOverflow, 748 llvm::Constant::getAllOnesValue(CGF.SizeTy), 749 size); 750 } 751 752 if (cookieSize == 0) 753 sizeWithoutCookie = size; 754 else 755 assert(sizeWithoutCookie && "didn't set sizeWithoutCookie?"); 756 757 return size; 758 } 759 760 static void StoreAnyExprIntoOneUnit(CodeGenFunction &CGF, const Expr *Init, 761 QualType AllocType, llvm::Value *NewPtr) { 762 // FIXME: Refactor with EmitExprAsInit. 763 CharUnits Alignment = CGF.getContext().getTypeAlignInChars(AllocType); 764 switch (CGF.getEvaluationKind(AllocType)) { 765 case TEK_Scalar: 766 CGF.EmitScalarInit(Init, nullptr, 767 CGF.MakeAddrLValue(NewPtr, AllocType, Alignment), false); 768 return; 769 case TEK_Complex: 770 CGF.EmitComplexExprIntoLValue(Init, CGF.MakeAddrLValue(NewPtr, AllocType, 771 Alignment), 772 /*isInit*/ true); 773 return; 774 case TEK_Aggregate: { 775 AggValueSlot Slot 776 = AggValueSlot::forAddr(NewPtr, Alignment, AllocType.getQualifiers(), 777 AggValueSlot::IsDestructed, 778 AggValueSlot::DoesNotNeedGCBarriers, 779 AggValueSlot::IsNotAliased); 780 CGF.EmitAggExpr(Init, Slot); 781 return; 782 } 783 } 784 llvm_unreachable("bad evaluation kind"); 785 } 786 787 void CodeGenFunction::EmitNewArrayInitializer( 788 const CXXNewExpr *E, QualType ElementType, llvm::Type *ElementTy, 789 llvm::Value *BeginPtr, llvm::Value *NumElements, 790 llvm::Value *AllocSizeWithoutCookie) { 791 // If we have a type with trivial initialization and no initializer, 792 // there's nothing to do. 793 if (!E->hasInitializer()) 794 return; 795 796 llvm::Value *CurPtr = BeginPtr; 797 798 unsigned InitListElements = 0; 799 800 const Expr *Init = E->getInitializer(); 801 llvm::AllocaInst *EndOfInit = nullptr; 802 QualType::DestructionKind DtorKind = ElementType.isDestructedType(); 803 EHScopeStack::stable_iterator Cleanup; 804 llvm::Instruction *CleanupDominator = nullptr; 805 806 // If the initializer is an initializer list, first do the explicit elements. 807 if (const InitListExpr *ILE = dyn_cast<InitListExpr>(Init)) { 808 InitListElements = ILE->getNumInits(); 809 810 // If this is a multi-dimensional array new, we will initialize multiple 811 // elements with each init list element. 812 QualType AllocType = E->getAllocatedType(); 813 if (const ConstantArrayType *CAT = dyn_cast_or_null<ConstantArrayType>( 814 AllocType->getAsArrayTypeUnsafe())) { 815 unsigned AS = CurPtr->getType()->getPointerAddressSpace(); 816 ElementTy = ConvertTypeForMem(AllocType); 817 llvm::Type *AllocPtrTy = ElementTy->getPointerTo(AS); 818 CurPtr = Builder.CreateBitCast(CurPtr, AllocPtrTy); 819 InitListElements *= getContext().getConstantArrayElementCount(CAT); 820 } 821 822 // Enter a partial-destruction Cleanup if necessary. 823 if (needsEHCleanup(DtorKind)) { 824 // In principle we could tell the Cleanup where we are more 825 // directly, but the control flow can get so varied here that it 826 // would actually be quite complex. Therefore we go through an 827 // alloca. 828 EndOfInit = CreateTempAlloca(BeginPtr->getType(), "array.init.end"); 829 CleanupDominator = Builder.CreateStore(BeginPtr, EndOfInit); 830 pushIrregularPartialArrayCleanup(BeginPtr, EndOfInit, ElementType, 831 getDestroyer(DtorKind)); 832 Cleanup = EHStack.stable_begin(); 833 } 834 835 for (unsigned i = 0, e = ILE->getNumInits(); i != e; ++i) { 836 // Tell the cleanup that it needs to destroy up to this 837 // element. TODO: some of these stores can be trivially 838 // observed to be unnecessary. 839 if (EndOfInit) 840 Builder.CreateStore(Builder.CreateBitCast(CurPtr, BeginPtr->getType()), 841 EndOfInit); 842 // FIXME: If the last initializer is an incomplete initializer list for 843 // an array, and we have an array filler, we can fold together the two 844 // initialization loops. 845 StoreAnyExprIntoOneUnit(*this, ILE->getInit(i), 846 ILE->getInit(i)->getType(), CurPtr); 847 CurPtr = Builder.CreateConstInBoundsGEP1_32(ElementTy, CurPtr, 1, 848 "array.exp.next"); 849 } 850 851 // The remaining elements are filled with the array filler expression. 852 Init = ILE->getArrayFiller(); 853 854 // Extract the initializer for the individual array elements by pulling 855 // out the array filler from all the nested initializer lists. This avoids 856 // generating a nested loop for the initialization. 857 while (Init && Init->getType()->isConstantArrayType()) { 858 auto *SubILE = dyn_cast<InitListExpr>(Init); 859 if (!SubILE) 860 break; 861 assert(SubILE->getNumInits() == 0 && "explicit inits in array filler?"); 862 Init = SubILE->getArrayFiller(); 863 } 864 865 // Switch back to initializing one base element at a time. 866 CurPtr = Builder.CreateBitCast(CurPtr, BeginPtr->getType()); 867 } 868 869 // Attempt to perform zero-initialization using memset. 870 auto TryMemsetInitialization = [&]() -> bool { 871 // FIXME: If the type is a pointer-to-data-member under the Itanium ABI, 872 // we can initialize with a memset to -1. 873 if (!CGM.getTypes().isZeroInitializable(ElementType)) 874 return false; 875 876 // Optimization: since zero initialization will just set the memory 877 // to all zeroes, generate a single memset to do it in one shot. 878 879 // Subtract out the size of any elements we've already initialized. 880 auto *RemainingSize = AllocSizeWithoutCookie; 881 if (InitListElements) { 882 // We know this can't overflow; we check this when doing the allocation. 883 auto *InitializedSize = llvm::ConstantInt::get( 884 RemainingSize->getType(), 885 getContext().getTypeSizeInChars(ElementType).getQuantity() * 886 InitListElements); 887 RemainingSize = Builder.CreateSub(RemainingSize, InitializedSize); 888 } 889 890 // Create the memset. 891 CharUnits Alignment = getContext().getTypeAlignInChars(ElementType); 892 Builder.CreateMemSet(CurPtr, Builder.getInt8(0), RemainingSize, 893 Alignment.getQuantity(), false); 894 return true; 895 }; 896 897 // If all elements have already been initialized, skip any further 898 // initialization. 899 llvm::ConstantInt *ConstNum = dyn_cast<llvm::ConstantInt>(NumElements); 900 if (ConstNum && ConstNum->getZExtValue() <= InitListElements) { 901 // If there was a Cleanup, deactivate it. 902 if (CleanupDominator) 903 DeactivateCleanupBlock(Cleanup, CleanupDominator); 904 return; 905 } 906 907 assert(Init && "have trailing elements to initialize but no initializer"); 908 909 // If this is a constructor call, try to optimize it out, and failing that 910 // emit a single loop to initialize all remaining elements. 911 if (const CXXConstructExpr *CCE = dyn_cast<CXXConstructExpr>(Init)) { 912 CXXConstructorDecl *Ctor = CCE->getConstructor(); 913 if (Ctor->isTrivial()) { 914 // If new expression did not specify value-initialization, then there 915 // is no initialization. 916 if (!CCE->requiresZeroInitialization() || Ctor->getParent()->isEmpty()) 917 return; 918 919 if (TryMemsetInitialization()) 920 return; 921 } 922 923 // Store the new Cleanup position for irregular Cleanups. 924 // 925 // FIXME: Share this cleanup with the constructor call emission rather than 926 // having it create a cleanup of its own. 927 if (EndOfInit) Builder.CreateStore(CurPtr, EndOfInit); 928 929 // Emit a constructor call loop to initialize the remaining elements. 930 if (InitListElements) 931 NumElements = Builder.CreateSub( 932 NumElements, 933 llvm::ConstantInt::get(NumElements->getType(), InitListElements)); 934 EmitCXXAggrConstructorCall(Ctor, NumElements, CurPtr, CCE, 935 CCE->requiresZeroInitialization()); 936 return; 937 } 938 939 // If this is value-initialization, we can usually use memset. 940 ImplicitValueInitExpr IVIE(ElementType); 941 if (isa<ImplicitValueInitExpr>(Init)) { 942 if (TryMemsetInitialization()) 943 return; 944 945 // Switch to an ImplicitValueInitExpr for the element type. This handles 946 // only one case: multidimensional array new of pointers to members. In 947 // all other cases, we already have an initializer for the array element. 948 Init = &IVIE; 949 } 950 951 // At this point we should have found an initializer for the individual 952 // elements of the array. 953 assert(getContext().hasSameUnqualifiedType(ElementType, Init->getType()) && 954 "got wrong type of element to initialize"); 955 956 // If we have an empty initializer list, we can usually use memset. 957 if (auto *ILE = dyn_cast<InitListExpr>(Init)) 958 if (ILE->getNumInits() == 0 && TryMemsetInitialization()) 959 return; 960 961 // Create the loop blocks. 962 llvm::BasicBlock *EntryBB = Builder.GetInsertBlock(); 963 llvm::BasicBlock *LoopBB = createBasicBlock("new.loop"); 964 llvm::BasicBlock *ContBB = createBasicBlock("new.loop.end"); 965 966 // Find the end of the array, hoisted out of the loop. 967 llvm::Value *EndPtr = 968 Builder.CreateInBoundsGEP(BeginPtr, NumElements, "array.end"); 969 970 // If the number of elements isn't constant, we have to now check if there is 971 // anything left to initialize. 972 if (!ConstNum) { 973 llvm::Value *IsEmpty = Builder.CreateICmpEQ(CurPtr, EndPtr, 974 "array.isempty"); 975 Builder.CreateCondBr(IsEmpty, ContBB, LoopBB); 976 } 977 978 // Enter the loop. 979 EmitBlock(LoopBB); 980 981 // Set up the current-element phi. 982 llvm::PHINode *CurPtrPhi = 983 Builder.CreatePHI(CurPtr->getType(), 2, "array.cur"); 984 CurPtrPhi->addIncoming(CurPtr, EntryBB); 985 CurPtr = CurPtrPhi; 986 987 // Store the new Cleanup position for irregular Cleanups. 988 if (EndOfInit) Builder.CreateStore(CurPtr, EndOfInit); 989 990 // Enter a partial-destruction Cleanup if necessary. 991 if (!CleanupDominator && needsEHCleanup(DtorKind)) { 992 pushRegularPartialArrayCleanup(BeginPtr, CurPtr, ElementType, 993 getDestroyer(DtorKind)); 994 Cleanup = EHStack.stable_begin(); 995 CleanupDominator = Builder.CreateUnreachable(); 996 } 997 998 // Emit the initializer into this element. 999 StoreAnyExprIntoOneUnit(*this, Init, Init->getType(), CurPtr); 1000 1001 // Leave the Cleanup if we entered one. 1002 if (CleanupDominator) { 1003 DeactivateCleanupBlock(Cleanup, CleanupDominator); 1004 CleanupDominator->eraseFromParent(); 1005 } 1006 1007 // Advance to the next element by adjusting the pointer type as necessary. 1008 llvm::Value *NextPtr = 1009 Builder.CreateConstInBoundsGEP1_32(ElementTy, CurPtr, 1, "array.next"); 1010 1011 // Check whether we've gotten to the end of the array and, if so, 1012 // exit the loop. 1013 llvm::Value *IsEnd = Builder.CreateICmpEQ(NextPtr, EndPtr, "array.atend"); 1014 Builder.CreateCondBr(IsEnd, ContBB, LoopBB); 1015 CurPtrPhi->addIncoming(NextPtr, Builder.GetInsertBlock()); 1016 1017 EmitBlock(ContBB); 1018 } 1019 1020 static void EmitNewInitializer(CodeGenFunction &CGF, const CXXNewExpr *E, 1021 QualType ElementType, llvm::Type *ElementTy, 1022 llvm::Value *NewPtr, llvm::Value *NumElements, 1023 llvm::Value *AllocSizeWithoutCookie) { 1024 ApplyDebugLocation DL(CGF, E); 1025 if (E->isArray()) 1026 CGF.EmitNewArrayInitializer(E, ElementType, ElementTy, NewPtr, NumElements, 1027 AllocSizeWithoutCookie); 1028 else if (const Expr *Init = E->getInitializer()) 1029 StoreAnyExprIntoOneUnit(CGF, Init, E->getAllocatedType(), NewPtr); 1030 } 1031 1032 /// Emit a call to an operator new or operator delete function, as implicitly 1033 /// created by new-expressions and delete-expressions. 1034 static RValue EmitNewDeleteCall(CodeGenFunction &CGF, 1035 const FunctionDecl *Callee, 1036 const FunctionProtoType *CalleeType, 1037 const CallArgList &Args) { 1038 llvm::Instruction *CallOrInvoke; 1039 llvm::Value *CalleeAddr = CGF.CGM.GetAddrOfFunction(Callee); 1040 RValue RV = 1041 CGF.EmitCall(CGF.CGM.getTypes().arrangeFreeFunctionCall( 1042 Args, CalleeType, /*chainCall=*/false), 1043 CalleeAddr, ReturnValueSlot(), Args, Callee, &CallOrInvoke); 1044 1045 /// C++1y [expr.new]p10: 1046 /// [In a new-expression,] an implementation is allowed to omit a call 1047 /// to a replaceable global allocation function. 1048 /// 1049 /// We model such elidable calls with the 'builtin' attribute. 1050 llvm::Function *Fn = dyn_cast<llvm::Function>(CalleeAddr); 1051 if (Callee->isReplaceableGlobalAllocationFunction() && 1052 Fn && Fn->hasFnAttribute(llvm::Attribute::NoBuiltin)) { 1053 // FIXME: Add addAttribute to CallSite. 1054 if (llvm::CallInst *CI = dyn_cast<llvm::CallInst>(CallOrInvoke)) 1055 CI->addAttribute(llvm::AttributeSet::FunctionIndex, 1056 llvm::Attribute::Builtin); 1057 else if (llvm::InvokeInst *II = dyn_cast<llvm::InvokeInst>(CallOrInvoke)) 1058 II->addAttribute(llvm::AttributeSet::FunctionIndex, 1059 llvm::Attribute::Builtin); 1060 else 1061 llvm_unreachable("unexpected kind of call instruction"); 1062 } 1063 1064 return RV; 1065 } 1066 1067 RValue CodeGenFunction::EmitBuiltinNewDeleteCall(const FunctionProtoType *Type, 1068 const Expr *Arg, 1069 bool IsDelete) { 1070 CallArgList Args; 1071 const Stmt *ArgS = Arg; 1072 EmitCallArgs(Args, *Type->param_type_begin(), 1073 ConstExprIterator(&ArgS), ConstExprIterator(&ArgS + 1)); 1074 // Find the allocation or deallocation function that we're calling. 1075 ASTContext &Ctx = getContext(); 1076 DeclarationName Name = Ctx.DeclarationNames 1077 .getCXXOperatorName(IsDelete ? OO_Delete : OO_New); 1078 for (auto *Decl : Ctx.getTranslationUnitDecl()->lookup(Name)) 1079 if (auto *FD = dyn_cast<FunctionDecl>(Decl)) 1080 if (Ctx.hasSameType(FD->getType(), QualType(Type, 0))) 1081 return EmitNewDeleteCall(*this, cast<FunctionDecl>(Decl), Type, Args); 1082 llvm_unreachable("predeclared global operator new/delete is missing"); 1083 } 1084 1085 namespace { 1086 /// A cleanup to call the given 'operator delete' function upon 1087 /// abnormal exit from a new expression. 1088 class CallDeleteDuringNew : public EHScopeStack::Cleanup { 1089 size_t NumPlacementArgs; 1090 const FunctionDecl *OperatorDelete; 1091 llvm::Value *Ptr; 1092 llvm::Value *AllocSize; 1093 1094 RValue *getPlacementArgs() { return reinterpret_cast<RValue*>(this+1); } 1095 1096 public: 1097 static size_t getExtraSize(size_t NumPlacementArgs) { 1098 return NumPlacementArgs * sizeof(RValue); 1099 } 1100 1101 CallDeleteDuringNew(size_t NumPlacementArgs, 1102 const FunctionDecl *OperatorDelete, 1103 llvm::Value *Ptr, 1104 llvm::Value *AllocSize) 1105 : NumPlacementArgs(NumPlacementArgs), OperatorDelete(OperatorDelete), 1106 Ptr(Ptr), AllocSize(AllocSize) {} 1107 1108 void setPlacementArg(unsigned I, RValue Arg) { 1109 assert(I < NumPlacementArgs && "index out of range"); 1110 getPlacementArgs()[I] = Arg; 1111 } 1112 1113 void Emit(CodeGenFunction &CGF, Flags flags) override { 1114 const FunctionProtoType *FPT 1115 = OperatorDelete->getType()->getAs<FunctionProtoType>(); 1116 assert(FPT->getNumParams() == NumPlacementArgs + 1 || 1117 (FPT->getNumParams() == 2 && NumPlacementArgs == 0)); 1118 1119 CallArgList DeleteArgs; 1120 1121 // The first argument is always a void*. 1122 FunctionProtoType::param_type_iterator AI = FPT->param_type_begin(); 1123 DeleteArgs.add(RValue::get(Ptr), *AI++); 1124 1125 // A member 'operator delete' can take an extra 'size_t' argument. 1126 if (FPT->getNumParams() == NumPlacementArgs + 2) 1127 DeleteArgs.add(RValue::get(AllocSize), *AI++); 1128 1129 // Pass the rest of the arguments, which must match exactly. 1130 for (unsigned I = 0; I != NumPlacementArgs; ++I) 1131 DeleteArgs.add(getPlacementArgs()[I], *AI++); 1132 1133 // Call 'operator delete'. 1134 EmitNewDeleteCall(CGF, OperatorDelete, FPT, DeleteArgs); 1135 } 1136 }; 1137 1138 /// A cleanup to call the given 'operator delete' function upon 1139 /// abnormal exit from a new expression when the new expression is 1140 /// conditional. 1141 class CallDeleteDuringConditionalNew : public EHScopeStack::Cleanup { 1142 size_t NumPlacementArgs; 1143 const FunctionDecl *OperatorDelete; 1144 DominatingValue<RValue>::saved_type Ptr; 1145 DominatingValue<RValue>::saved_type AllocSize; 1146 1147 DominatingValue<RValue>::saved_type *getPlacementArgs() { 1148 return reinterpret_cast<DominatingValue<RValue>::saved_type*>(this+1); 1149 } 1150 1151 public: 1152 static size_t getExtraSize(size_t NumPlacementArgs) { 1153 return NumPlacementArgs * sizeof(DominatingValue<RValue>::saved_type); 1154 } 1155 1156 CallDeleteDuringConditionalNew(size_t NumPlacementArgs, 1157 const FunctionDecl *OperatorDelete, 1158 DominatingValue<RValue>::saved_type Ptr, 1159 DominatingValue<RValue>::saved_type AllocSize) 1160 : NumPlacementArgs(NumPlacementArgs), OperatorDelete(OperatorDelete), 1161 Ptr(Ptr), AllocSize(AllocSize) {} 1162 1163 void setPlacementArg(unsigned I, DominatingValue<RValue>::saved_type Arg) { 1164 assert(I < NumPlacementArgs && "index out of range"); 1165 getPlacementArgs()[I] = Arg; 1166 } 1167 1168 void Emit(CodeGenFunction &CGF, Flags flags) override { 1169 const FunctionProtoType *FPT 1170 = OperatorDelete->getType()->getAs<FunctionProtoType>(); 1171 assert(FPT->getNumParams() == NumPlacementArgs + 1 || 1172 (FPT->getNumParams() == 2 && NumPlacementArgs == 0)); 1173 1174 CallArgList DeleteArgs; 1175 1176 // The first argument is always a void*. 1177 FunctionProtoType::param_type_iterator AI = FPT->param_type_begin(); 1178 DeleteArgs.add(Ptr.restore(CGF), *AI++); 1179 1180 // A member 'operator delete' can take an extra 'size_t' argument. 1181 if (FPT->getNumParams() == NumPlacementArgs + 2) { 1182 RValue RV = AllocSize.restore(CGF); 1183 DeleteArgs.add(RV, *AI++); 1184 } 1185 1186 // Pass the rest of the arguments, which must match exactly. 1187 for (unsigned I = 0; I != NumPlacementArgs; ++I) { 1188 RValue RV = getPlacementArgs()[I].restore(CGF); 1189 DeleteArgs.add(RV, *AI++); 1190 } 1191 1192 // Call 'operator delete'. 1193 EmitNewDeleteCall(CGF, OperatorDelete, FPT, DeleteArgs); 1194 } 1195 }; 1196 } 1197 1198 /// Enter a cleanup to call 'operator delete' if the initializer in a 1199 /// new-expression throws. 1200 static void EnterNewDeleteCleanup(CodeGenFunction &CGF, 1201 const CXXNewExpr *E, 1202 llvm::Value *NewPtr, 1203 llvm::Value *AllocSize, 1204 const CallArgList &NewArgs) { 1205 // If we're not inside a conditional branch, then the cleanup will 1206 // dominate and we can do the easier (and more efficient) thing. 1207 if (!CGF.isInConditionalBranch()) { 1208 CallDeleteDuringNew *Cleanup = CGF.EHStack 1209 .pushCleanupWithExtra<CallDeleteDuringNew>(EHCleanup, 1210 E->getNumPlacementArgs(), 1211 E->getOperatorDelete(), 1212 NewPtr, AllocSize); 1213 for (unsigned I = 0, N = E->getNumPlacementArgs(); I != N; ++I) 1214 Cleanup->setPlacementArg(I, NewArgs[I+1].RV); 1215 1216 return; 1217 } 1218 1219 // Otherwise, we need to save all this stuff. 1220 DominatingValue<RValue>::saved_type SavedNewPtr = 1221 DominatingValue<RValue>::save(CGF, RValue::get(NewPtr)); 1222 DominatingValue<RValue>::saved_type SavedAllocSize = 1223 DominatingValue<RValue>::save(CGF, RValue::get(AllocSize)); 1224 1225 CallDeleteDuringConditionalNew *Cleanup = CGF.EHStack 1226 .pushCleanupWithExtra<CallDeleteDuringConditionalNew>(EHCleanup, 1227 E->getNumPlacementArgs(), 1228 E->getOperatorDelete(), 1229 SavedNewPtr, 1230 SavedAllocSize); 1231 for (unsigned I = 0, N = E->getNumPlacementArgs(); I != N; ++I) 1232 Cleanup->setPlacementArg(I, 1233 DominatingValue<RValue>::save(CGF, NewArgs[I+1].RV)); 1234 1235 CGF.initFullExprCleanup(); 1236 } 1237 1238 llvm::Value *CodeGenFunction::EmitCXXNewExpr(const CXXNewExpr *E) { 1239 // The element type being allocated. 1240 QualType allocType = getContext().getBaseElementType(E->getAllocatedType()); 1241 1242 // 1. Build a call to the allocation function. 1243 FunctionDecl *allocator = E->getOperatorNew(); 1244 const FunctionProtoType *allocatorType = 1245 allocator->getType()->castAs<FunctionProtoType>(); 1246 1247 CallArgList allocatorArgs; 1248 1249 // The allocation size is the first argument. 1250 QualType sizeType = getContext().getSizeType(); 1251 1252 // If there is a brace-initializer, cannot allocate fewer elements than inits. 1253 unsigned minElements = 0; 1254 if (E->isArray() && E->hasInitializer()) { 1255 if (const InitListExpr *ILE = dyn_cast<InitListExpr>(E->getInitializer())) 1256 minElements = ILE->getNumInits(); 1257 } 1258 1259 llvm::Value *numElements = nullptr; 1260 llvm::Value *allocSizeWithoutCookie = nullptr; 1261 llvm::Value *allocSize = 1262 EmitCXXNewAllocSize(*this, E, minElements, numElements, 1263 allocSizeWithoutCookie); 1264 1265 allocatorArgs.add(RValue::get(allocSize), sizeType); 1266 1267 // We start at 1 here because the first argument (the allocation size) 1268 // has already been emitted. 1269 EmitCallArgs(allocatorArgs, allocatorType, E->placement_arg_begin(), 1270 E->placement_arg_end(), /* CalleeDecl */ nullptr, 1271 /*ParamsToSkip*/ 1); 1272 1273 // Emit the allocation call. If the allocator is a global placement 1274 // operator, just "inline" it directly. 1275 RValue RV; 1276 if (allocator->isReservedGlobalPlacementOperator()) { 1277 assert(allocatorArgs.size() == 2); 1278 RV = allocatorArgs[1].RV; 1279 // TODO: kill any unnecessary computations done for the size 1280 // argument. 1281 } else { 1282 RV = EmitNewDeleteCall(*this, allocator, allocatorType, allocatorArgs); 1283 } 1284 1285 // Emit a null check on the allocation result if the allocation 1286 // function is allowed to return null (because it has a non-throwing 1287 // exception spec or is the reserved placement new) and we have an 1288 // interesting initializer. 1289 bool nullCheck = E->shouldNullCheckAllocation(getContext()) && 1290 (!allocType.isPODType(getContext()) || E->hasInitializer()); 1291 1292 llvm::BasicBlock *nullCheckBB = nullptr; 1293 llvm::BasicBlock *contBB = nullptr; 1294 1295 llvm::Value *allocation = RV.getScalarVal(); 1296 unsigned AS = allocation->getType()->getPointerAddressSpace(); 1297 1298 // The null-check means that the initializer is conditionally 1299 // evaluated. 1300 ConditionalEvaluation conditional(*this); 1301 1302 if (nullCheck) { 1303 conditional.begin(*this); 1304 1305 nullCheckBB = Builder.GetInsertBlock(); 1306 llvm::BasicBlock *notNullBB = createBasicBlock("new.notnull"); 1307 contBB = createBasicBlock("new.cont"); 1308 1309 llvm::Value *isNull = Builder.CreateIsNull(allocation, "new.isnull"); 1310 Builder.CreateCondBr(isNull, contBB, notNullBB); 1311 EmitBlock(notNullBB); 1312 } 1313 1314 // If there's an operator delete, enter a cleanup to call it if an 1315 // exception is thrown. 1316 EHScopeStack::stable_iterator operatorDeleteCleanup; 1317 llvm::Instruction *cleanupDominator = nullptr; 1318 if (E->getOperatorDelete() && 1319 !E->getOperatorDelete()->isReservedGlobalPlacementOperator()) { 1320 EnterNewDeleteCleanup(*this, E, allocation, allocSize, allocatorArgs); 1321 operatorDeleteCleanup = EHStack.stable_begin(); 1322 cleanupDominator = Builder.CreateUnreachable(); 1323 } 1324 1325 assert((allocSize == allocSizeWithoutCookie) == 1326 CalculateCookiePadding(*this, E).isZero()); 1327 if (allocSize != allocSizeWithoutCookie) { 1328 assert(E->isArray()); 1329 allocation = CGM.getCXXABI().InitializeArrayCookie(*this, allocation, 1330 numElements, 1331 E, allocType); 1332 } 1333 1334 llvm::Type *elementTy = ConvertTypeForMem(allocType); 1335 llvm::Type *elementPtrTy = elementTy->getPointerTo(AS); 1336 llvm::Value *result = Builder.CreateBitCast(allocation, elementPtrTy); 1337 1338 EmitNewInitializer(*this, E, allocType, elementTy, result, numElements, 1339 allocSizeWithoutCookie); 1340 if (E->isArray()) { 1341 // NewPtr is a pointer to the base element type. If we're 1342 // allocating an array of arrays, we'll need to cast back to the 1343 // array pointer type. 1344 llvm::Type *resultType = ConvertTypeForMem(E->getType()); 1345 if (result->getType() != resultType) 1346 result = Builder.CreateBitCast(result, resultType); 1347 } 1348 1349 // Deactivate the 'operator delete' cleanup if we finished 1350 // initialization. 1351 if (operatorDeleteCleanup.isValid()) { 1352 DeactivateCleanupBlock(operatorDeleteCleanup, cleanupDominator); 1353 cleanupDominator->eraseFromParent(); 1354 } 1355 1356 if (nullCheck) { 1357 conditional.end(*this); 1358 1359 llvm::BasicBlock *notNullBB = Builder.GetInsertBlock(); 1360 EmitBlock(contBB); 1361 1362 llvm::PHINode *PHI = Builder.CreatePHI(result->getType(), 2); 1363 PHI->addIncoming(result, notNullBB); 1364 PHI->addIncoming(llvm::Constant::getNullValue(result->getType()), 1365 nullCheckBB); 1366 1367 result = PHI; 1368 } 1369 1370 return result; 1371 } 1372 1373 void CodeGenFunction::EmitDeleteCall(const FunctionDecl *DeleteFD, 1374 llvm::Value *Ptr, 1375 QualType DeleteTy) { 1376 assert(DeleteFD->getOverloadedOperator() == OO_Delete); 1377 1378 const FunctionProtoType *DeleteFTy = 1379 DeleteFD->getType()->getAs<FunctionProtoType>(); 1380 1381 CallArgList DeleteArgs; 1382 1383 // Check if we need to pass the size to the delete operator. 1384 llvm::Value *Size = nullptr; 1385 QualType SizeTy; 1386 if (DeleteFTy->getNumParams() == 2) { 1387 SizeTy = DeleteFTy->getParamType(1); 1388 CharUnits DeleteTypeSize = getContext().getTypeSizeInChars(DeleteTy); 1389 Size = llvm::ConstantInt::get(ConvertType(SizeTy), 1390 DeleteTypeSize.getQuantity()); 1391 } 1392 1393 QualType ArgTy = DeleteFTy->getParamType(0); 1394 llvm::Value *DeletePtr = Builder.CreateBitCast(Ptr, ConvertType(ArgTy)); 1395 DeleteArgs.add(RValue::get(DeletePtr), ArgTy); 1396 1397 if (Size) 1398 DeleteArgs.add(RValue::get(Size), SizeTy); 1399 1400 // Emit the call to delete. 1401 EmitNewDeleteCall(*this, DeleteFD, DeleteFTy, DeleteArgs); 1402 } 1403 1404 namespace { 1405 /// Calls the given 'operator delete' on a single object. 1406 struct CallObjectDelete : EHScopeStack::Cleanup { 1407 llvm::Value *Ptr; 1408 const FunctionDecl *OperatorDelete; 1409 QualType ElementType; 1410 1411 CallObjectDelete(llvm::Value *Ptr, 1412 const FunctionDecl *OperatorDelete, 1413 QualType ElementType) 1414 : Ptr(Ptr), OperatorDelete(OperatorDelete), ElementType(ElementType) {} 1415 1416 void Emit(CodeGenFunction &CGF, Flags flags) override { 1417 CGF.EmitDeleteCall(OperatorDelete, Ptr, ElementType); 1418 } 1419 }; 1420 } 1421 1422 void 1423 CodeGenFunction::pushCallObjectDeleteCleanup(const FunctionDecl *OperatorDelete, 1424 llvm::Value *CompletePtr, 1425 QualType ElementType) { 1426 EHStack.pushCleanup<CallObjectDelete>(NormalAndEHCleanup, CompletePtr, 1427 OperatorDelete, ElementType); 1428 } 1429 1430 /// Emit the code for deleting a single object. 1431 static void EmitObjectDelete(CodeGenFunction &CGF, 1432 const CXXDeleteExpr *DE, 1433 llvm::Value *Ptr, 1434 QualType ElementType) { 1435 // Find the destructor for the type, if applicable. If the 1436 // destructor is virtual, we'll just emit the vcall and return. 1437 const CXXDestructorDecl *Dtor = nullptr; 1438 if (const RecordType *RT = ElementType->getAs<RecordType>()) { 1439 CXXRecordDecl *RD = cast<CXXRecordDecl>(RT->getDecl()); 1440 if (RD->hasDefinition() && !RD->hasTrivialDestructor()) { 1441 Dtor = RD->getDestructor(); 1442 1443 if (Dtor->isVirtual()) { 1444 CGF.CGM.getCXXABI().emitVirtualObjectDelete(CGF, DE, Ptr, ElementType, 1445 Dtor); 1446 return; 1447 } 1448 } 1449 } 1450 1451 // Make sure that we call delete even if the dtor throws. 1452 // This doesn't have to a conditional cleanup because we're going 1453 // to pop it off in a second. 1454 const FunctionDecl *OperatorDelete = DE->getOperatorDelete(); 1455 CGF.EHStack.pushCleanup<CallObjectDelete>(NormalAndEHCleanup, 1456 Ptr, OperatorDelete, ElementType); 1457 1458 if (Dtor) 1459 CGF.EmitCXXDestructorCall(Dtor, Dtor_Complete, 1460 /*ForVirtualBase=*/false, 1461 /*Delegating=*/false, 1462 Ptr); 1463 else if (CGF.getLangOpts().ObjCAutoRefCount && 1464 ElementType->isObjCLifetimeType()) { 1465 switch (ElementType.getObjCLifetime()) { 1466 case Qualifiers::OCL_None: 1467 case Qualifiers::OCL_ExplicitNone: 1468 case Qualifiers::OCL_Autoreleasing: 1469 break; 1470 1471 case Qualifiers::OCL_Strong: { 1472 // Load the pointer value. 1473 llvm::Value *PtrValue = CGF.Builder.CreateLoad(Ptr, 1474 ElementType.isVolatileQualified()); 1475 1476 CGF.EmitARCRelease(PtrValue, ARCPreciseLifetime); 1477 break; 1478 } 1479 1480 case Qualifiers::OCL_Weak: 1481 CGF.EmitARCDestroyWeak(Ptr); 1482 break; 1483 } 1484 } 1485 1486 CGF.PopCleanupBlock(); 1487 } 1488 1489 namespace { 1490 /// Calls the given 'operator delete' on an array of objects. 1491 struct CallArrayDelete : EHScopeStack::Cleanup { 1492 llvm::Value *Ptr; 1493 const FunctionDecl *OperatorDelete; 1494 llvm::Value *NumElements; 1495 QualType ElementType; 1496 CharUnits CookieSize; 1497 1498 CallArrayDelete(llvm::Value *Ptr, 1499 const FunctionDecl *OperatorDelete, 1500 llvm::Value *NumElements, 1501 QualType ElementType, 1502 CharUnits CookieSize) 1503 : Ptr(Ptr), OperatorDelete(OperatorDelete), NumElements(NumElements), 1504 ElementType(ElementType), CookieSize(CookieSize) {} 1505 1506 void Emit(CodeGenFunction &CGF, Flags flags) override { 1507 const FunctionProtoType *DeleteFTy = 1508 OperatorDelete->getType()->getAs<FunctionProtoType>(); 1509 assert(DeleteFTy->getNumParams() == 1 || DeleteFTy->getNumParams() == 2); 1510 1511 CallArgList Args; 1512 1513 // Pass the pointer as the first argument. 1514 QualType VoidPtrTy = DeleteFTy->getParamType(0); 1515 llvm::Value *DeletePtr 1516 = CGF.Builder.CreateBitCast(Ptr, CGF.ConvertType(VoidPtrTy)); 1517 Args.add(RValue::get(DeletePtr), VoidPtrTy); 1518 1519 // Pass the original requested size as the second argument. 1520 if (DeleteFTy->getNumParams() == 2) { 1521 QualType size_t = DeleteFTy->getParamType(1); 1522 llvm::IntegerType *SizeTy 1523 = cast<llvm::IntegerType>(CGF.ConvertType(size_t)); 1524 1525 CharUnits ElementTypeSize = 1526 CGF.CGM.getContext().getTypeSizeInChars(ElementType); 1527 1528 // The size of an element, multiplied by the number of elements. 1529 llvm::Value *Size 1530 = llvm::ConstantInt::get(SizeTy, ElementTypeSize.getQuantity()); 1531 Size = CGF.Builder.CreateMul(Size, NumElements); 1532 1533 // Plus the size of the cookie if applicable. 1534 if (!CookieSize.isZero()) { 1535 llvm::Value *CookieSizeV 1536 = llvm::ConstantInt::get(SizeTy, CookieSize.getQuantity()); 1537 Size = CGF.Builder.CreateAdd(Size, CookieSizeV); 1538 } 1539 1540 Args.add(RValue::get(Size), size_t); 1541 } 1542 1543 // Emit the call to delete. 1544 EmitNewDeleteCall(CGF, OperatorDelete, DeleteFTy, Args); 1545 } 1546 }; 1547 } 1548 1549 /// Emit the code for deleting an array of objects. 1550 static void EmitArrayDelete(CodeGenFunction &CGF, 1551 const CXXDeleteExpr *E, 1552 llvm::Value *deletedPtr, 1553 QualType elementType) { 1554 llvm::Value *numElements = nullptr; 1555 llvm::Value *allocatedPtr = nullptr; 1556 CharUnits cookieSize; 1557 CGF.CGM.getCXXABI().ReadArrayCookie(CGF, deletedPtr, E, elementType, 1558 numElements, allocatedPtr, cookieSize); 1559 1560 assert(allocatedPtr && "ReadArrayCookie didn't set allocated pointer"); 1561 1562 // Make sure that we call delete even if one of the dtors throws. 1563 const FunctionDecl *operatorDelete = E->getOperatorDelete(); 1564 CGF.EHStack.pushCleanup<CallArrayDelete>(NormalAndEHCleanup, 1565 allocatedPtr, operatorDelete, 1566 numElements, elementType, 1567 cookieSize); 1568 1569 // Destroy the elements. 1570 if (QualType::DestructionKind dtorKind = elementType.isDestructedType()) { 1571 assert(numElements && "no element count for a type with a destructor!"); 1572 1573 llvm::Value *arrayEnd = 1574 CGF.Builder.CreateInBoundsGEP(deletedPtr, numElements, "delete.end"); 1575 1576 // Note that it is legal to allocate a zero-length array, and we 1577 // can never fold the check away because the length should always 1578 // come from a cookie. 1579 CGF.emitArrayDestroy(deletedPtr, arrayEnd, elementType, 1580 CGF.getDestroyer(dtorKind), 1581 /*checkZeroLength*/ true, 1582 CGF.needsEHCleanup(dtorKind)); 1583 } 1584 1585 // Pop the cleanup block. 1586 CGF.PopCleanupBlock(); 1587 } 1588 1589 void CodeGenFunction::EmitCXXDeleteExpr(const CXXDeleteExpr *E) { 1590 const Expr *Arg = E->getArgument(); 1591 llvm::Value *Ptr = EmitScalarExpr(Arg); 1592 1593 // Null check the pointer. 1594 llvm::BasicBlock *DeleteNotNull = createBasicBlock("delete.notnull"); 1595 llvm::BasicBlock *DeleteEnd = createBasicBlock("delete.end"); 1596 1597 llvm::Value *IsNull = Builder.CreateIsNull(Ptr, "isnull"); 1598 1599 Builder.CreateCondBr(IsNull, DeleteEnd, DeleteNotNull); 1600 EmitBlock(DeleteNotNull); 1601 1602 // We might be deleting a pointer to array. If so, GEP down to the 1603 // first non-array element. 1604 // (this assumes that A(*)[3][7] is converted to [3 x [7 x %A]]*) 1605 QualType DeleteTy = Arg->getType()->getAs<PointerType>()->getPointeeType(); 1606 if (DeleteTy->isConstantArrayType()) { 1607 llvm::Value *Zero = Builder.getInt32(0); 1608 SmallVector<llvm::Value*,8> GEP; 1609 1610 GEP.push_back(Zero); // point at the outermost array 1611 1612 // For each layer of array type we're pointing at: 1613 while (const ConstantArrayType *Arr 1614 = getContext().getAsConstantArrayType(DeleteTy)) { 1615 // 1. Unpeel the array type. 1616 DeleteTy = Arr->getElementType(); 1617 1618 // 2. GEP to the first element of the array. 1619 GEP.push_back(Zero); 1620 } 1621 1622 Ptr = Builder.CreateInBoundsGEP(Ptr, GEP, "del.first"); 1623 } 1624 1625 assert(ConvertTypeForMem(DeleteTy) == 1626 cast<llvm::PointerType>(Ptr->getType())->getElementType()); 1627 1628 if (E->isArrayForm()) { 1629 EmitArrayDelete(*this, E, Ptr, DeleteTy); 1630 } else { 1631 EmitObjectDelete(*this, E, Ptr, DeleteTy); 1632 } 1633 1634 EmitBlock(DeleteEnd); 1635 } 1636 1637 static bool isGLValueFromPointerDeref(const Expr *E) { 1638 E = E->IgnoreParens(); 1639 1640 if (const auto *CE = dyn_cast<CastExpr>(E)) { 1641 if (!CE->getSubExpr()->isGLValue()) 1642 return false; 1643 return isGLValueFromPointerDeref(CE->getSubExpr()); 1644 } 1645 1646 if (const auto *OVE = dyn_cast<OpaqueValueExpr>(E)) 1647 return isGLValueFromPointerDeref(OVE->getSourceExpr()); 1648 1649 if (const auto *BO = dyn_cast<BinaryOperator>(E)) 1650 if (BO->getOpcode() == BO_Comma) 1651 return isGLValueFromPointerDeref(BO->getRHS()); 1652 1653 if (const auto *ACO = dyn_cast<AbstractConditionalOperator>(E)) 1654 return isGLValueFromPointerDeref(ACO->getTrueExpr()) || 1655 isGLValueFromPointerDeref(ACO->getFalseExpr()); 1656 1657 // C++11 [expr.sub]p1: 1658 // The expression E1[E2] is identical (by definition) to *((E1)+(E2)) 1659 if (isa<ArraySubscriptExpr>(E)) 1660 return true; 1661 1662 if (const auto *UO = dyn_cast<UnaryOperator>(E)) 1663 if (UO->getOpcode() == UO_Deref) 1664 return true; 1665 1666 return false; 1667 } 1668 1669 static llvm::Value *EmitTypeidFromVTable(CodeGenFunction &CGF, const Expr *E, 1670 llvm::Type *StdTypeInfoPtrTy) { 1671 // Get the vtable pointer. 1672 llvm::Value *ThisPtr = CGF.EmitLValue(E).getAddress(); 1673 1674 // C++ [expr.typeid]p2: 1675 // If the glvalue expression is obtained by applying the unary * operator to 1676 // a pointer and the pointer is a null pointer value, the typeid expression 1677 // throws the std::bad_typeid exception. 1678 // 1679 // However, this paragraph's intent is not clear. We choose a very generous 1680 // interpretation which implores us to consider comma operators, conditional 1681 // operators, parentheses and other such constructs. 1682 QualType SrcRecordTy = E->getType(); 1683 if (CGF.CGM.getCXXABI().shouldTypeidBeNullChecked( 1684 isGLValueFromPointerDeref(E), SrcRecordTy)) { 1685 llvm::BasicBlock *BadTypeidBlock = 1686 CGF.createBasicBlock("typeid.bad_typeid"); 1687 llvm::BasicBlock *EndBlock = CGF.createBasicBlock("typeid.end"); 1688 1689 llvm::Value *IsNull = CGF.Builder.CreateIsNull(ThisPtr); 1690 CGF.Builder.CreateCondBr(IsNull, BadTypeidBlock, EndBlock); 1691 1692 CGF.EmitBlock(BadTypeidBlock); 1693 CGF.CGM.getCXXABI().EmitBadTypeidCall(CGF); 1694 CGF.EmitBlock(EndBlock); 1695 } 1696 1697 return CGF.CGM.getCXXABI().EmitTypeid(CGF, SrcRecordTy, ThisPtr, 1698 StdTypeInfoPtrTy); 1699 } 1700 1701 llvm::Value *CodeGenFunction::EmitCXXTypeidExpr(const CXXTypeidExpr *E) { 1702 llvm::Type *StdTypeInfoPtrTy = 1703 ConvertType(E->getType())->getPointerTo(); 1704 1705 if (E->isTypeOperand()) { 1706 llvm::Constant *TypeInfo = 1707 CGM.GetAddrOfRTTIDescriptor(E->getTypeOperand(getContext())); 1708 return Builder.CreateBitCast(TypeInfo, StdTypeInfoPtrTy); 1709 } 1710 1711 // C++ [expr.typeid]p2: 1712 // When typeid is applied to a glvalue expression whose type is a 1713 // polymorphic class type, the result refers to a std::type_info object 1714 // representing the type of the most derived object (that is, the dynamic 1715 // type) to which the glvalue refers. 1716 if (E->isPotentiallyEvaluated()) 1717 return EmitTypeidFromVTable(*this, E->getExprOperand(), 1718 StdTypeInfoPtrTy); 1719 1720 QualType OperandTy = E->getExprOperand()->getType(); 1721 return Builder.CreateBitCast(CGM.GetAddrOfRTTIDescriptor(OperandTy), 1722 StdTypeInfoPtrTy); 1723 } 1724 1725 static llvm::Value *EmitDynamicCastToNull(CodeGenFunction &CGF, 1726 QualType DestTy) { 1727 llvm::Type *DestLTy = CGF.ConvertType(DestTy); 1728 if (DestTy->isPointerType()) 1729 return llvm::Constant::getNullValue(DestLTy); 1730 1731 /// C++ [expr.dynamic.cast]p9: 1732 /// A failed cast to reference type throws std::bad_cast 1733 if (!CGF.CGM.getCXXABI().EmitBadCastCall(CGF)) 1734 return nullptr; 1735 1736 CGF.EmitBlock(CGF.createBasicBlock("dynamic_cast.end")); 1737 return llvm::UndefValue::get(DestLTy); 1738 } 1739 1740 llvm::Value *CodeGenFunction::EmitDynamicCast(llvm::Value *Value, 1741 const CXXDynamicCastExpr *DCE) { 1742 QualType DestTy = DCE->getTypeAsWritten(); 1743 1744 if (DCE->isAlwaysNull()) 1745 if (llvm::Value *T = EmitDynamicCastToNull(*this, DestTy)) 1746 return T; 1747 1748 QualType SrcTy = DCE->getSubExpr()->getType(); 1749 1750 // C++ [expr.dynamic.cast]p7: 1751 // If T is "pointer to cv void," then the result is a pointer to the most 1752 // derived object pointed to by v. 1753 const PointerType *DestPTy = DestTy->getAs<PointerType>(); 1754 1755 bool isDynamicCastToVoid; 1756 QualType SrcRecordTy; 1757 QualType DestRecordTy; 1758 if (DestPTy) { 1759 isDynamicCastToVoid = DestPTy->getPointeeType()->isVoidType(); 1760 SrcRecordTy = SrcTy->castAs<PointerType>()->getPointeeType(); 1761 DestRecordTy = DestPTy->getPointeeType(); 1762 } else { 1763 isDynamicCastToVoid = false; 1764 SrcRecordTy = SrcTy; 1765 DestRecordTy = DestTy->castAs<ReferenceType>()->getPointeeType(); 1766 } 1767 1768 assert(SrcRecordTy->isRecordType() && "source type must be a record type!"); 1769 1770 // C++ [expr.dynamic.cast]p4: 1771 // If the value of v is a null pointer value in the pointer case, the result 1772 // is the null pointer value of type T. 1773 bool ShouldNullCheckSrcValue = 1774 CGM.getCXXABI().shouldDynamicCastCallBeNullChecked(SrcTy->isPointerType(), 1775 SrcRecordTy); 1776 1777 llvm::BasicBlock *CastNull = nullptr; 1778 llvm::BasicBlock *CastNotNull = nullptr; 1779 llvm::BasicBlock *CastEnd = createBasicBlock("dynamic_cast.end"); 1780 1781 if (ShouldNullCheckSrcValue) { 1782 CastNull = createBasicBlock("dynamic_cast.null"); 1783 CastNotNull = createBasicBlock("dynamic_cast.notnull"); 1784 1785 llvm::Value *IsNull = Builder.CreateIsNull(Value); 1786 Builder.CreateCondBr(IsNull, CastNull, CastNotNull); 1787 EmitBlock(CastNotNull); 1788 } 1789 1790 if (isDynamicCastToVoid) { 1791 Value = CGM.getCXXABI().EmitDynamicCastToVoid(*this, Value, SrcRecordTy, 1792 DestTy); 1793 } else { 1794 assert(DestRecordTy->isRecordType() && 1795 "destination type must be a record type!"); 1796 Value = CGM.getCXXABI().EmitDynamicCastCall(*this, Value, SrcRecordTy, 1797 DestTy, DestRecordTy, CastEnd); 1798 } 1799 1800 if (ShouldNullCheckSrcValue) { 1801 EmitBranch(CastEnd); 1802 1803 EmitBlock(CastNull); 1804 EmitBranch(CastEnd); 1805 } 1806 1807 EmitBlock(CastEnd); 1808 1809 if (ShouldNullCheckSrcValue) { 1810 llvm::PHINode *PHI = Builder.CreatePHI(Value->getType(), 2); 1811 PHI->addIncoming(Value, CastNotNull); 1812 PHI->addIncoming(llvm::Constant::getNullValue(Value->getType()), CastNull); 1813 1814 Value = PHI; 1815 } 1816 1817 return Value; 1818 } 1819 1820 void CodeGenFunction::EmitLambdaExpr(const LambdaExpr *E, AggValueSlot Slot) { 1821 RunCleanupsScope Scope(*this); 1822 LValue SlotLV = 1823 MakeAddrLValue(Slot.getAddr(), E->getType(), Slot.getAlignment()); 1824 1825 CXXRecordDecl::field_iterator CurField = E->getLambdaClass()->field_begin(); 1826 for (LambdaExpr::capture_init_iterator i = E->capture_init_begin(), 1827 e = E->capture_init_end(); 1828 i != e; ++i, ++CurField) { 1829 // Emit initialization 1830 LValue LV = EmitLValueForFieldInitialization(SlotLV, *CurField); 1831 if (CurField->hasCapturedVLAType()) { 1832 auto VAT = CurField->getCapturedVLAType(); 1833 EmitStoreThroughLValue(RValue::get(VLASizeMap[VAT->getSizeExpr()]), LV); 1834 } else { 1835 ArrayRef<VarDecl *> ArrayIndexes; 1836 if (CurField->getType()->isArrayType()) 1837 ArrayIndexes = E->getCaptureInitIndexVars(i); 1838 EmitInitializerForField(*CurField, LV, *i, ArrayIndexes); 1839 } 1840 } 1841 } 1842