CGExprCXX.cpp revision 176edba5311f6eff0cad2631449885ddf4fbc9ea
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 24using namespace clang; 25using namespace CodeGen; 26 27static 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 72RValue 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 85RValue 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 96static 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. 106RValue 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 // Compute the object pointer. 124 const Expr *Base = ME->getBase(); 125 bool CanUseVirtualCall = MD->isVirtual() && !ME->hasQualifier(); 126 127 const CXXMethodDecl *DevirtualizedMethod = nullptr; 128 if (CanUseVirtualCall && CanDevirtualizeMemberFunctionCall(Base, MD)) { 129 const CXXRecordDecl *BestDynamicDecl = Base->getBestDynamicClassType(); 130 DevirtualizedMethod = MD->getCorrespondingMethodInClass(BestDynamicDecl); 131 assert(DevirtualizedMethod); 132 const CXXRecordDecl *DevirtualizedClass = DevirtualizedMethod->getParent(); 133 const Expr *Inner = Base->ignoreParenBaseCasts(); 134 if (DevirtualizedMethod->getReturnType().getCanonicalType() != 135 MD->getReturnType().getCanonicalType()) 136 // If the return types are not the same, this might be a case where more 137 // code needs to run to compensate for it. For example, the derived 138 // method might return a type that inherits form from the return 139 // type of MD and has a prefix. 140 // For now we just avoid devirtualizing these covariant cases. 141 DevirtualizedMethod = nullptr; 142 else if (getCXXRecord(Inner) == DevirtualizedClass) 143 // If the class of the Inner expression is where the dynamic method 144 // is defined, build the this pointer from it. 145 Base = Inner; 146 else if (getCXXRecord(Base) != DevirtualizedClass) { 147 // If the method is defined in a class that is not the best dynamic 148 // one or the one of the full expression, we would have to build 149 // a derived-to-base cast to compute the correct this pointer, but 150 // we don't have support for that yet, so do a virtual call. 151 DevirtualizedMethod = nullptr; 152 } 153 } 154 155 llvm::Value *This; 156 if (ME->isArrow()) 157 This = EmitScalarExpr(Base); 158 else 159 This = EmitLValue(Base).getAddress(); 160 161 162 if (MD->isTrivial()) { 163 if (isa<CXXDestructorDecl>(MD)) return RValue::get(nullptr); 164 if (isa<CXXConstructorDecl>(MD) && 165 cast<CXXConstructorDecl>(MD)->isDefaultConstructor()) 166 return RValue::get(nullptr); 167 168 if (MD->isCopyAssignmentOperator() || MD->isMoveAssignmentOperator()) { 169 // We don't like to generate the trivial copy/move assignment operator 170 // when it isn't necessary; just produce the proper effect here. 171 llvm::Value *RHS = EmitLValue(*CE->arg_begin()).getAddress(); 172 EmitAggregateAssign(This, RHS, CE->getType()); 173 return RValue::get(This); 174 } 175 176 if (isa<CXXConstructorDecl>(MD) && 177 cast<CXXConstructorDecl>(MD)->isCopyOrMoveConstructor()) { 178 // Trivial move and copy ctor are the same. 179 assert(CE->getNumArgs() == 1 && "unexpected argcount for trivial ctor"); 180 llvm::Value *RHS = EmitLValue(*CE->arg_begin()).getAddress(); 181 EmitAggregateCopy(This, RHS, CE->arg_begin()->getType()); 182 return RValue::get(This); 183 } 184 llvm_unreachable("unknown trivial member function"); 185 } 186 187 // Compute the function type we're calling. 188 const CXXMethodDecl *CalleeDecl = DevirtualizedMethod ? DevirtualizedMethod : MD; 189 const CGFunctionInfo *FInfo = nullptr; 190 if (const CXXDestructorDecl *Dtor = dyn_cast<CXXDestructorDecl>(CalleeDecl)) 191 FInfo = &CGM.getTypes().arrangeCXXStructorDeclaration( 192 Dtor, StructorType::Complete); 193 else if (const CXXConstructorDecl *Ctor = dyn_cast<CXXConstructorDecl>(CalleeDecl)) 194 FInfo = &CGM.getTypes().arrangeCXXStructorDeclaration( 195 Ctor, StructorType::Complete); 196 else 197 FInfo = &CGM.getTypes().arrangeCXXMethodDeclaration(CalleeDecl); 198 199 llvm::FunctionType *Ty = CGM.getTypes().GetFunctionType(*FInfo); 200 201 // C++ [class.virtual]p12: 202 // Explicit qualification with the scope operator (5.1) suppresses the 203 // virtual call mechanism. 204 // 205 // We also don't emit a virtual call if the base expression has a record type 206 // because then we know what the type is. 207 bool UseVirtualCall = CanUseVirtualCall && !DevirtualizedMethod; 208 llvm::Value *Callee; 209 210 if (const CXXDestructorDecl *Dtor = dyn_cast<CXXDestructorDecl>(MD)) { 211 assert(CE->arg_begin() == CE->arg_end() && 212 "Destructor shouldn't have explicit parameters"); 213 assert(ReturnValue.isNull() && "Destructor shouldn't have return value"); 214 if (UseVirtualCall) { 215 CGM.getCXXABI().EmitVirtualDestructorCall(*this, Dtor, Dtor_Complete, 216 This, CE); 217 } else { 218 if (getLangOpts().AppleKext && 219 MD->isVirtual() && 220 ME->hasQualifier()) 221 Callee = BuildAppleKextVirtualCall(MD, ME->getQualifier(), Ty); 222 else if (!DevirtualizedMethod) 223 Callee = 224 CGM.getAddrOfCXXStructor(Dtor, StructorType::Complete, FInfo, Ty); 225 else { 226 const CXXDestructorDecl *DDtor = 227 cast<CXXDestructorDecl>(DevirtualizedMethod); 228 Callee = CGM.GetAddrOfFunction(GlobalDecl(DDtor, Dtor_Complete), Ty); 229 } 230 EmitCXXMemberOrOperatorCall(MD, Callee, ReturnValue, This, 231 /*ImplicitParam=*/nullptr, QualType(), CE); 232 } 233 return RValue::get(nullptr); 234 } 235 236 if (const CXXConstructorDecl *Ctor = dyn_cast<CXXConstructorDecl>(MD)) { 237 Callee = CGM.GetAddrOfFunction(GlobalDecl(Ctor, Ctor_Complete), Ty); 238 } else if (UseVirtualCall) { 239 Callee = CGM.getCXXABI().getVirtualFunctionPointer(*this, MD, This, Ty); 240 } else { 241 if (getLangOpts().AppleKext && 242 MD->isVirtual() && 243 ME->hasQualifier()) 244 Callee = BuildAppleKextVirtualCall(MD, ME->getQualifier(), Ty); 245 else if (!DevirtualizedMethod) 246 Callee = CGM.GetAddrOfFunction(MD, Ty); 247 else { 248 Callee = CGM.GetAddrOfFunction(DevirtualizedMethod, Ty); 249 } 250 } 251 252 if (MD->isVirtual()) { 253 This = CGM.getCXXABI().adjustThisArgumentForVirtualFunctionCall( 254 *this, MD, This, UseVirtualCall); 255 } 256 257 return EmitCXXMemberOrOperatorCall(MD, Callee, ReturnValue, This, 258 /*ImplicitParam=*/nullptr, QualType(), CE); 259} 260 261RValue 262CodeGenFunction::EmitCXXMemberPointerCallExpr(const CXXMemberCallExpr *E, 263 ReturnValueSlot ReturnValue) { 264 const BinaryOperator *BO = 265 cast<BinaryOperator>(E->getCallee()->IgnoreParens()); 266 const Expr *BaseExpr = BO->getLHS(); 267 const Expr *MemFnExpr = BO->getRHS(); 268 269 const MemberPointerType *MPT = 270 MemFnExpr->getType()->castAs<MemberPointerType>(); 271 272 const FunctionProtoType *FPT = 273 MPT->getPointeeType()->castAs<FunctionProtoType>(); 274 const CXXRecordDecl *RD = 275 cast<CXXRecordDecl>(MPT->getClass()->getAs<RecordType>()->getDecl()); 276 277 // Get the member function pointer. 278 llvm::Value *MemFnPtr = EmitScalarExpr(MemFnExpr); 279 280 // Emit the 'this' pointer. 281 llvm::Value *This; 282 283 if (BO->getOpcode() == BO_PtrMemI) 284 This = EmitScalarExpr(BaseExpr); 285 else 286 This = EmitLValue(BaseExpr).getAddress(); 287 288 EmitTypeCheck(TCK_MemberCall, E->getExprLoc(), This, 289 QualType(MPT->getClass(), 0)); 290 291 // Ask the ABI to load the callee. Note that This is modified. 292 llvm::Value *Callee = 293 CGM.getCXXABI().EmitLoadOfMemberFunctionPointer(*this, BO, This, MemFnPtr, MPT); 294 295 CallArgList Args; 296 297 QualType ThisType = 298 getContext().getPointerType(getContext().getTagDeclType(RD)); 299 300 // Push the this ptr. 301 Args.add(RValue::get(This), ThisType); 302 303 RequiredArgs required = RequiredArgs::forPrototypePlus(FPT, 1); 304 305 // And the rest of the call args 306 EmitCallArgs(Args, FPT, E->arg_begin(), E->arg_end(), E->getDirectCallee()); 307 return EmitCall(CGM.getTypes().arrangeCXXMethodCall(Args, FPT, required), 308 Callee, ReturnValue, Args); 309} 310 311RValue 312CodeGenFunction::EmitCXXOperatorMemberCallExpr(const CXXOperatorCallExpr *E, 313 const CXXMethodDecl *MD, 314 ReturnValueSlot ReturnValue) { 315 assert(MD->isInstance() && 316 "Trying to emit a member call expr on a static method!"); 317 LValue LV = EmitLValue(E->getArg(0)); 318 llvm::Value *This = LV.getAddress(); 319 320 if ((MD->isCopyAssignmentOperator() || MD->isMoveAssignmentOperator()) && 321 MD->isTrivial() && !MD->getParent()->mayInsertExtraPadding()) { 322 llvm::Value *Src = EmitLValue(E->getArg(1)).getAddress(); 323 QualType Ty = E->getType(); 324 EmitAggregateAssign(This, Src, Ty); 325 return RValue::get(This); 326 } 327 328 llvm::Value *Callee = EmitCXXOperatorMemberCallee(E, MD, This); 329 return EmitCXXMemberOrOperatorCall(MD, Callee, ReturnValue, This, 330 /*ImplicitParam=*/nullptr, QualType(), E); 331} 332 333RValue CodeGenFunction::EmitCUDAKernelCallExpr(const CUDAKernelCallExpr *E, 334 ReturnValueSlot ReturnValue) { 335 return CGM.getCUDARuntime().EmitCUDAKernelCallExpr(*this, E, ReturnValue); 336} 337 338static void EmitNullBaseClassInitialization(CodeGenFunction &CGF, 339 llvm::Value *DestPtr, 340 const CXXRecordDecl *Base) { 341 if (Base->isEmpty()) 342 return; 343 344 DestPtr = CGF.EmitCastToVoidPtr(DestPtr); 345 346 const ASTRecordLayout &Layout = CGF.getContext().getASTRecordLayout(Base); 347 CharUnits Size = Layout.getNonVirtualSize(); 348 CharUnits Align = Layout.getNonVirtualAlignment(); 349 350 llvm::Value *SizeVal = CGF.CGM.getSize(Size); 351 352 // If the type contains a pointer to data member we can't memset it to zero. 353 // Instead, create a null constant and copy it to the destination. 354 // TODO: there are other patterns besides zero that we can usefully memset, 355 // like -1, which happens to be the pattern used by member-pointers. 356 // TODO: isZeroInitializable can be over-conservative in the case where a 357 // virtual base contains a member pointer. 358 if (!CGF.CGM.getTypes().isZeroInitializable(Base)) { 359 llvm::Constant *NullConstant = CGF.CGM.EmitNullConstantForBase(Base); 360 361 llvm::GlobalVariable *NullVariable = 362 new llvm::GlobalVariable(CGF.CGM.getModule(), NullConstant->getType(), 363 /*isConstant=*/true, 364 llvm::GlobalVariable::PrivateLinkage, 365 NullConstant, Twine()); 366 NullVariable->setAlignment(Align.getQuantity()); 367 llvm::Value *SrcPtr = CGF.EmitCastToVoidPtr(NullVariable); 368 369 // Get and call the appropriate llvm.memcpy overload. 370 CGF.Builder.CreateMemCpy(DestPtr, SrcPtr, SizeVal, Align.getQuantity()); 371 return; 372 } 373 374 // Otherwise, just memset the whole thing to zero. This is legal 375 // because in LLVM, all default initializers (other than the ones we just 376 // handled above) are guaranteed to have a bit pattern of all zeros. 377 CGF.Builder.CreateMemSet(DestPtr, CGF.Builder.getInt8(0), SizeVal, 378 Align.getQuantity()); 379} 380 381void 382CodeGenFunction::EmitCXXConstructExpr(const CXXConstructExpr *E, 383 AggValueSlot Dest) { 384 assert(!Dest.isIgnored() && "Must have a destination!"); 385 const CXXConstructorDecl *CD = E->getConstructor(); 386 387 // If we require zero initialization before (or instead of) calling the 388 // constructor, as can be the case with a non-user-provided default 389 // constructor, emit the zero initialization now, unless destination is 390 // already zeroed. 391 if (E->requiresZeroInitialization() && !Dest.isZeroed()) { 392 switch (E->getConstructionKind()) { 393 case CXXConstructExpr::CK_Delegating: 394 case CXXConstructExpr::CK_Complete: 395 EmitNullInitialization(Dest.getAddr(), E->getType()); 396 break; 397 case CXXConstructExpr::CK_VirtualBase: 398 case CXXConstructExpr::CK_NonVirtualBase: 399 EmitNullBaseClassInitialization(*this, Dest.getAddr(), CD->getParent()); 400 break; 401 } 402 } 403 404 // If this is a call to a trivial default constructor, do nothing. 405 if (CD->isTrivial() && CD->isDefaultConstructor()) 406 return; 407 408 // Elide the constructor if we're constructing from a temporary. 409 // The temporary check is required because Sema sets this on NRVO 410 // returns. 411 if (getLangOpts().ElideConstructors && E->isElidable()) { 412 assert(getContext().hasSameUnqualifiedType(E->getType(), 413 E->getArg(0)->getType())); 414 if (E->getArg(0)->isTemporaryObject(getContext(), CD->getParent())) { 415 EmitAggExpr(E->getArg(0), Dest); 416 return; 417 } 418 } 419 420 if (const ConstantArrayType *arrayType 421 = getContext().getAsConstantArrayType(E->getType())) { 422 EmitCXXAggrConstructorCall(CD, arrayType, Dest.getAddr(), E); 423 } else { 424 CXXCtorType Type = Ctor_Complete; 425 bool ForVirtualBase = false; 426 bool Delegating = false; 427 428 switch (E->getConstructionKind()) { 429 case CXXConstructExpr::CK_Delegating: 430 // We should be emitting a constructor; GlobalDecl will assert this 431 Type = CurGD.getCtorType(); 432 Delegating = true; 433 break; 434 435 case CXXConstructExpr::CK_Complete: 436 Type = Ctor_Complete; 437 break; 438 439 case CXXConstructExpr::CK_VirtualBase: 440 ForVirtualBase = true; 441 // fall-through 442 443 case CXXConstructExpr::CK_NonVirtualBase: 444 Type = Ctor_Base; 445 } 446 447 // Call the constructor. 448 EmitCXXConstructorCall(CD, Type, ForVirtualBase, Delegating, Dest.getAddr(), 449 E); 450 } 451} 452 453void 454CodeGenFunction::EmitSynthesizedCXXCopyCtor(llvm::Value *Dest, 455 llvm::Value *Src, 456 const Expr *Exp) { 457 if (const ExprWithCleanups *E = dyn_cast<ExprWithCleanups>(Exp)) 458 Exp = E->getSubExpr(); 459 assert(isa<CXXConstructExpr>(Exp) && 460 "EmitSynthesizedCXXCopyCtor - unknown copy ctor expr"); 461 const CXXConstructExpr* E = cast<CXXConstructExpr>(Exp); 462 const CXXConstructorDecl *CD = E->getConstructor(); 463 RunCleanupsScope Scope(*this); 464 465 // If we require zero initialization before (or instead of) calling the 466 // constructor, as can be the case with a non-user-provided default 467 // constructor, emit the zero initialization now. 468 // FIXME. Do I still need this for a copy ctor synthesis? 469 if (E->requiresZeroInitialization()) 470 EmitNullInitialization(Dest, E->getType()); 471 472 assert(!getContext().getAsConstantArrayType(E->getType()) 473 && "EmitSynthesizedCXXCopyCtor - Copied-in Array"); 474 EmitSynthesizedCXXCopyCtorCall(CD, Dest, Src, E); 475} 476 477static CharUnits CalculateCookiePadding(CodeGenFunction &CGF, 478 const CXXNewExpr *E) { 479 if (!E->isArray()) 480 return CharUnits::Zero(); 481 482 // No cookie is required if the operator new[] being used is the 483 // reserved placement operator new[]. 484 if (E->getOperatorNew()->isReservedGlobalPlacementOperator()) 485 return CharUnits::Zero(); 486 487 return CGF.CGM.getCXXABI().GetArrayCookieSize(E); 488} 489 490static llvm::Value *EmitCXXNewAllocSize(CodeGenFunction &CGF, 491 const CXXNewExpr *e, 492 unsigned minElements, 493 llvm::Value *&numElements, 494 llvm::Value *&sizeWithoutCookie) { 495 QualType type = e->getAllocatedType(); 496 497 if (!e->isArray()) { 498 CharUnits typeSize = CGF.getContext().getTypeSizeInChars(type); 499 sizeWithoutCookie 500 = llvm::ConstantInt::get(CGF.SizeTy, typeSize.getQuantity()); 501 return sizeWithoutCookie; 502 } 503 504 // The width of size_t. 505 unsigned sizeWidth = CGF.SizeTy->getBitWidth(); 506 507 // Figure out the cookie size. 508 llvm::APInt cookieSize(sizeWidth, 509 CalculateCookiePadding(CGF, e).getQuantity()); 510 511 // Emit the array size expression. 512 // We multiply the size of all dimensions for NumElements. 513 // e.g for 'int[2][3]', ElemType is 'int' and NumElements is 6. 514 numElements = CGF.EmitScalarExpr(e->getArraySize()); 515 assert(isa<llvm::IntegerType>(numElements->getType())); 516 517 // The number of elements can be have an arbitrary integer type; 518 // essentially, we need to multiply it by a constant factor, add a 519 // cookie size, and verify that the result is representable as a 520 // size_t. That's just a gloss, though, and it's wrong in one 521 // important way: if the count is negative, it's an error even if 522 // the cookie size would bring the total size >= 0. 523 bool isSigned 524 = e->getArraySize()->getType()->isSignedIntegerOrEnumerationType(); 525 llvm::IntegerType *numElementsType 526 = cast<llvm::IntegerType>(numElements->getType()); 527 unsigned numElementsWidth = numElementsType->getBitWidth(); 528 529 // Compute the constant factor. 530 llvm::APInt arraySizeMultiplier(sizeWidth, 1); 531 while (const ConstantArrayType *CAT 532 = CGF.getContext().getAsConstantArrayType(type)) { 533 type = CAT->getElementType(); 534 arraySizeMultiplier *= CAT->getSize(); 535 } 536 537 CharUnits typeSize = CGF.getContext().getTypeSizeInChars(type); 538 llvm::APInt typeSizeMultiplier(sizeWidth, typeSize.getQuantity()); 539 typeSizeMultiplier *= arraySizeMultiplier; 540 541 // This will be a size_t. 542 llvm::Value *size; 543 544 // If someone is doing 'new int[42]' there is no need to do a dynamic check. 545 // Don't bloat the -O0 code. 546 if (llvm::ConstantInt *numElementsC = 547 dyn_cast<llvm::ConstantInt>(numElements)) { 548 const llvm::APInt &count = numElementsC->getValue(); 549 550 bool hasAnyOverflow = false; 551 552 // If 'count' was a negative number, it's an overflow. 553 if (isSigned && count.isNegative()) 554 hasAnyOverflow = true; 555 556 // We want to do all this arithmetic in size_t. If numElements is 557 // wider than that, check whether it's already too big, and if so, 558 // overflow. 559 else if (numElementsWidth > sizeWidth && 560 numElementsWidth - sizeWidth > count.countLeadingZeros()) 561 hasAnyOverflow = true; 562 563 // Okay, compute a count at the right width. 564 llvm::APInt adjustedCount = count.zextOrTrunc(sizeWidth); 565 566 // If there is a brace-initializer, we cannot allocate fewer elements than 567 // there are initializers. If we do, that's treated like an overflow. 568 if (adjustedCount.ult(minElements)) 569 hasAnyOverflow = true; 570 571 // Scale numElements by that. This might overflow, but we don't 572 // care because it only overflows if allocationSize does, too, and 573 // if that overflows then we shouldn't use this. 574 numElements = llvm::ConstantInt::get(CGF.SizeTy, 575 adjustedCount * arraySizeMultiplier); 576 577 // Compute the size before cookie, and track whether it overflowed. 578 bool overflow; 579 llvm::APInt allocationSize 580 = adjustedCount.umul_ov(typeSizeMultiplier, overflow); 581 hasAnyOverflow |= overflow; 582 583 // Add in the cookie, and check whether it's overflowed. 584 if (cookieSize != 0) { 585 // Save the current size without a cookie. This shouldn't be 586 // used if there was overflow. 587 sizeWithoutCookie = llvm::ConstantInt::get(CGF.SizeTy, allocationSize); 588 589 allocationSize = allocationSize.uadd_ov(cookieSize, overflow); 590 hasAnyOverflow |= overflow; 591 } 592 593 // On overflow, produce a -1 so operator new will fail. 594 if (hasAnyOverflow) { 595 size = llvm::Constant::getAllOnesValue(CGF.SizeTy); 596 } else { 597 size = llvm::ConstantInt::get(CGF.SizeTy, allocationSize); 598 } 599 600 // Otherwise, we might need to use the overflow intrinsics. 601 } else { 602 // There are up to five conditions we need to test for: 603 // 1) if isSigned, we need to check whether numElements is negative; 604 // 2) if numElementsWidth > sizeWidth, we need to check whether 605 // numElements is larger than something representable in size_t; 606 // 3) if minElements > 0, we need to check whether numElements is smaller 607 // than that. 608 // 4) we need to compute 609 // sizeWithoutCookie := numElements * typeSizeMultiplier 610 // and check whether it overflows; and 611 // 5) if we need a cookie, we need to compute 612 // size := sizeWithoutCookie + cookieSize 613 // and check whether it overflows. 614 615 llvm::Value *hasOverflow = nullptr; 616 617 // If numElementsWidth > sizeWidth, then one way or another, we're 618 // going to have to do a comparison for (2), and this happens to 619 // take care of (1), too. 620 if (numElementsWidth > sizeWidth) { 621 llvm::APInt threshold(numElementsWidth, 1); 622 threshold <<= sizeWidth; 623 624 llvm::Value *thresholdV 625 = llvm::ConstantInt::get(numElementsType, threshold); 626 627 hasOverflow = CGF.Builder.CreateICmpUGE(numElements, thresholdV); 628 numElements = CGF.Builder.CreateTrunc(numElements, CGF.SizeTy); 629 630 // Otherwise, if we're signed, we want to sext up to size_t. 631 } else if (isSigned) { 632 if (numElementsWidth < sizeWidth) 633 numElements = CGF.Builder.CreateSExt(numElements, CGF.SizeTy); 634 635 // If there's a non-1 type size multiplier, then we can do the 636 // signedness check at the same time as we do the multiply 637 // because a negative number times anything will cause an 638 // unsigned overflow. Otherwise, we have to do it here. But at least 639 // in this case, we can subsume the >= minElements check. 640 if (typeSizeMultiplier == 1) 641 hasOverflow = CGF.Builder.CreateICmpSLT(numElements, 642 llvm::ConstantInt::get(CGF.SizeTy, minElements)); 643 644 // Otherwise, zext up to size_t if necessary. 645 } else if (numElementsWidth < sizeWidth) { 646 numElements = CGF.Builder.CreateZExt(numElements, CGF.SizeTy); 647 } 648 649 assert(numElements->getType() == CGF.SizeTy); 650 651 if (minElements) { 652 // Don't allow allocation of fewer elements than we have initializers. 653 if (!hasOverflow) { 654 hasOverflow = CGF.Builder.CreateICmpULT(numElements, 655 llvm::ConstantInt::get(CGF.SizeTy, minElements)); 656 } else if (numElementsWidth > sizeWidth) { 657 // The other existing overflow subsumes this check. 658 // We do an unsigned comparison, since any signed value < -1 is 659 // taken care of either above or below. 660 hasOverflow = CGF.Builder.CreateOr(hasOverflow, 661 CGF.Builder.CreateICmpULT(numElements, 662 llvm::ConstantInt::get(CGF.SizeTy, minElements))); 663 } 664 } 665 666 size = numElements; 667 668 // Multiply by the type size if necessary. This multiplier 669 // includes all the factors for nested arrays. 670 // 671 // This step also causes numElements to be scaled up by the 672 // nested-array factor if necessary. Overflow on this computation 673 // can be ignored because the result shouldn't be used if 674 // allocation fails. 675 if (typeSizeMultiplier != 1) { 676 llvm::Value *umul_with_overflow 677 = CGF.CGM.getIntrinsic(llvm::Intrinsic::umul_with_overflow, CGF.SizeTy); 678 679 llvm::Value *tsmV = 680 llvm::ConstantInt::get(CGF.SizeTy, typeSizeMultiplier); 681 llvm::Value *result = 682 CGF.Builder.CreateCall2(umul_with_overflow, size, tsmV); 683 684 llvm::Value *overflowed = CGF.Builder.CreateExtractValue(result, 1); 685 if (hasOverflow) 686 hasOverflow = CGF.Builder.CreateOr(hasOverflow, overflowed); 687 else 688 hasOverflow = overflowed; 689 690 size = CGF.Builder.CreateExtractValue(result, 0); 691 692 // Also scale up numElements by the array size multiplier. 693 if (arraySizeMultiplier != 1) { 694 // If the base element type size is 1, then we can re-use the 695 // multiply we just did. 696 if (typeSize.isOne()) { 697 assert(arraySizeMultiplier == typeSizeMultiplier); 698 numElements = size; 699 700 // Otherwise we need a separate multiply. 701 } else { 702 llvm::Value *asmV = 703 llvm::ConstantInt::get(CGF.SizeTy, arraySizeMultiplier); 704 numElements = CGF.Builder.CreateMul(numElements, asmV); 705 } 706 } 707 } else { 708 // numElements doesn't need to be scaled. 709 assert(arraySizeMultiplier == 1); 710 } 711 712 // Add in the cookie size if necessary. 713 if (cookieSize != 0) { 714 sizeWithoutCookie = size; 715 716 llvm::Value *uadd_with_overflow 717 = CGF.CGM.getIntrinsic(llvm::Intrinsic::uadd_with_overflow, CGF.SizeTy); 718 719 llvm::Value *cookieSizeV = llvm::ConstantInt::get(CGF.SizeTy, cookieSize); 720 llvm::Value *result = 721 CGF.Builder.CreateCall2(uadd_with_overflow, size, cookieSizeV); 722 723 llvm::Value *overflowed = CGF.Builder.CreateExtractValue(result, 1); 724 if (hasOverflow) 725 hasOverflow = CGF.Builder.CreateOr(hasOverflow, overflowed); 726 else 727 hasOverflow = overflowed; 728 729 size = CGF.Builder.CreateExtractValue(result, 0); 730 } 731 732 // If we had any possibility of dynamic overflow, make a select to 733 // overwrite 'size' with an all-ones value, which should cause 734 // operator new to throw. 735 if (hasOverflow) 736 size = CGF.Builder.CreateSelect(hasOverflow, 737 llvm::Constant::getAllOnesValue(CGF.SizeTy), 738 size); 739 } 740 741 if (cookieSize == 0) 742 sizeWithoutCookie = size; 743 else 744 assert(sizeWithoutCookie && "didn't set sizeWithoutCookie?"); 745 746 return size; 747} 748 749static void StoreAnyExprIntoOneUnit(CodeGenFunction &CGF, const Expr *Init, 750 QualType AllocType, llvm::Value *NewPtr) { 751 // FIXME: Refactor with EmitExprAsInit. 752 CharUnits Alignment = CGF.getContext().getTypeAlignInChars(AllocType); 753 switch (CGF.getEvaluationKind(AllocType)) { 754 case TEK_Scalar: 755 CGF.EmitScalarInit(Init, nullptr, CGF.MakeAddrLValue(NewPtr, AllocType, 756 Alignment), 757 false); 758 return; 759 case TEK_Complex: 760 CGF.EmitComplexExprIntoLValue(Init, CGF.MakeAddrLValue(NewPtr, AllocType, 761 Alignment), 762 /*isInit*/ true); 763 return; 764 case TEK_Aggregate: { 765 AggValueSlot Slot 766 = AggValueSlot::forAddr(NewPtr, Alignment, AllocType.getQualifiers(), 767 AggValueSlot::IsDestructed, 768 AggValueSlot::DoesNotNeedGCBarriers, 769 AggValueSlot::IsNotAliased); 770 CGF.EmitAggExpr(Init, Slot); 771 return; 772 } 773 } 774 llvm_unreachable("bad evaluation kind"); 775} 776 777void 778CodeGenFunction::EmitNewArrayInitializer(const CXXNewExpr *E, 779 QualType ElementType, 780 llvm::Value *BeginPtr, 781 llvm::Value *NumElements, 782 llvm::Value *AllocSizeWithoutCookie) { 783 // If we have a type with trivial initialization and no initializer, 784 // there's nothing to do. 785 if (!E->hasInitializer()) 786 return; 787 788 llvm::Value *CurPtr = BeginPtr; 789 790 unsigned InitListElements = 0; 791 792 const Expr *Init = E->getInitializer(); 793 llvm::AllocaInst *EndOfInit = nullptr; 794 QualType::DestructionKind DtorKind = ElementType.isDestructedType(); 795 EHScopeStack::stable_iterator Cleanup; 796 llvm::Instruction *CleanupDominator = nullptr; 797 798 // If the initializer is an initializer list, first do the explicit elements. 799 if (const InitListExpr *ILE = dyn_cast<InitListExpr>(Init)) { 800 InitListElements = ILE->getNumInits(); 801 802 // If this is a multi-dimensional array new, we will initialize multiple 803 // elements with each init list element. 804 QualType AllocType = E->getAllocatedType(); 805 if (const ConstantArrayType *CAT = dyn_cast_or_null<ConstantArrayType>( 806 AllocType->getAsArrayTypeUnsafe())) { 807 unsigned AS = CurPtr->getType()->getPointerAddressSpace(); 808 llvm::Type *AllocPtrTy = ConvertTypeForMem(AllocType)->getPointerTo(AS); 809 CurPtr = Builder.CreateBitCast(CurPtr, AllocPtrTy); 810 InitListElements *= getContext().getConstantArrayElementCount(CAT); 811 } 812 813 // Enter a partial-destruction Cleanup if necessary. 814 if (needsEHCleanup(DtorKind)) { 815 // In principle we could tell the Cleanup where we are more 816 // directly, but the control flow can get so varied here that it 817 // would actually be quite complex. Therefore we go through an 818 // alloca. 819 EndOfInit = CreateTempAlloca(BeginPtr->getType(), "array.init.end"); 820 CleanupDominator = Builder.CreateStore(BeginPtr, EndOfInit); 821 pushIrregularPartialArrayCleanup(BeginPtr, EndOfInit, ElementType, 822 getDestroyer(DtorKind)); 823 Cleanup = EHStack.stable_begin(); 824 } 825 826 for (unsigned i = 0, e = ILE->getNumInits(); i != e; ++i) { 827 // Tell the cleanup that it needs to destroy up to this 828 // element. TODO: some of these stores can be trivially 829 // observed to be unnecessary. 830 if (EndOfInit) 831 Builder.CreateStore(Builder.CreateBitCast(CurPtr, BeginPtr->getType()), 832 EndOfInit); 833 // FIXME: If the last initializer is an incomplete initializer list for 834 // an array, and we have an array filler, we can fold together the two 835 // initialization loops. 836 StoreAnyExprIntoOneUnit(*this, ILE->getInit(i), 837 ILE->getInit(i)->getType(), CurPtr); 838 CurPtr = Builder.CreateConstInBoundsGEP1_32(CurPtr, 1, "array.exp.next"); 839 } 840 841 // The remaining elements are filled with the array filler expression. 842 Init = ILE->getArrayFiller(); 843 844 // Extract the initializer for the individual array elements by pulling 845 // out the array filler from all the nested initializer lists. This avoids 846 // generating a nested loop for the initialization. 847 while (Init && Init->getType()->isConstantArrayType()) { 848 auto *SubILE = dyn_cast<InitListExpr>(Init); 849 if (!SubILE) 850 break; 851 assert(SubILE->getNumInits() == 0 && "explicit inits in array filler?"); 852 Init = SubILE->getArrayFiller(); 853 } 854 855 // Switch back to initializing one base element at a time. 856 CurPtr = Builder.CreateBitCast(CurPtr, BeginPtr->getType()); 857 } 858 859 // Attempt to perform zero-initialization using memset. 860 auto TryMemsetInitialization = [&]() -> bool { 861 // FIXME: If the type is a pointer-to-data-member under the Itanium ABI, 862 // we can initialize with a memset to -1. 863 if (!CGM.getTypes().isZeroInitializable(ElementType)) 864 return false; 865 866 // Optimization: since zero initialization will just set the memory 867 // to all zeroes, generate a single memset to do it in one shot. 868 869 // Subtract out the size of any elements we've already initialized. 870 auto *RemainingSize = AllocSizeWithoutCookie; 871 if (InitListElements) { 872 // We know this can't overflow; we check this when doing the allocation. 873 auto *InitializedSize = llvm::ConstantInt::get( 874 RemainingSize->getType(), 875 getContext().getTypeSizeInChars(ElementType).getQuantity() * 876 InitListElements); 877 RemainingSize = Builder.CreateSub(RemainingSize, InitializedSize); 878 } 879 880 // Create the memset. 881 CharUnits Alignment = getContext().getTypeAlignInChars(ElementType); 882 Builder.CreateMemSet(CurPtr, Builder.getInt8(0), RemainingSize, 883 Alignment.getQuantity(), false); 884 return true; 885 }; 886 887 // If all elements have already been initialized, skip any further 888 // initialization. 889 llvm::ConstantInt *ConstNum = dyn_cast<llvm::ConstantInt>(NumElements); 890 if (ConstNum && ConstNum->getZExtValue() <= InitListElements) { 891 // If there was a Cleanup, deactivate it. 892 if (CleanupDominator) 893 DeactivateCleanupBlock(Cleanup, CleanupDominator); 894 return; 895 } 896 897 assert(Init && "have trailing elements to initialize but no initializer"); 898 899 // If this is a constructor call, try to optimize it out, and failing that 900 // emit a single loop to initialize all remaining elements. 901 if (const CXXConstructExpr *CCE = dyn_cast<CXXConstructExpr>(Init)) { 902 CXXConstructorDecl *Ctor = CCE->getConstructor(); 903 if (Ctor->isTrivial()) { 904 // If new expression did not specify value-initialization, then there 905 // is no initialization. 906 if (!CCE->requiresZeroInitialization() || Ctor->getParent()->isEmpty()) 907 return; 908 909 if (TryMemsetInitialization()) 910 return; 911 } 912 913 // Store the new Cleanup position for irregular Cleanups. 914 // 915 // FIXME: Share this cleanup with the constructor call emission rather than 916 // having it create a cleanup of its own. 917 if (EndOfInit) Builder.CreateStore(CurPtr, EndOfInit); 918 919 // Emit a constructor call loop to initialize the remaining elements. 920 if (InitListElements) 921 NumElements = Builder.CreateSub( 922 NumElements, 923 llvm::ConstantInt::get(NumElements->getType(), InitListElements)); 924 EmitCXXAggrConstructorCall(Ctor, NumElements, CurPtr, CCE, 925 CCE->requiresZeroInitialization()); 926 return; 927 } 928 929 // If this is value-initialization, we can usually use memset. 930 ImplicitValueInitExpr IVIE(ElementType); 931 if (isa<ImplicitValueInitExpr>(Init)) { 932 if (TryMemsetInitialization()) 933 return; 934 935 // Switch to an ImplicitValueInitExpr for the element type. This handles 936 // only one case: multidimensional array new of pointers to members. In 937 // all other cases, we already have an initializer for the array element. 938 Init = &IVIE; 939 } 940 941 // At this point we should have found an initializer for the individual 942 // elements of the array. 943 assert(getContext().hasSameUnqualifiedType(ElementType, Init->getType()) && 944 "got wrong type of element to initialize"); 945 946 // If we have an empty initializer list, we can usually use memset. 947 if (auto *ILE = dyn_cast<InitListExpr>(Init)) 948 if (ILE->getNumInits() == 0 && TryMemsetInitialization()) 949 return; 950 951 // Create the loop blocks. 952 llvm::BasicBlock *EntryBB = Builder.GetInsertBlock(); 953 llvm::BasicBlock *LoopBB = createBasicBlock("new.loop"); 954 llvm::BasicBlock *ContBB = createBasicBlock("new.loop.end"); 955 956 // Find the end of the array, hoisted out of the loop. 957 llvm::Value *EndPtr = 958 Builder.CreateInBoundsGEP(BeginPtr, NumElements, "array.end"); 959 960 // If the number of elements isn't constant, we have to now check if there is 961 // anything left to initialize. 962 if (!ConstNum) { 963 llvm::Value *IsEmpty = Builder.CreateICmpEQ(CurPtr, EndPtr, 964 "array.isempty"); 965 Builder.CreateCondBr(IsEmpty, ContBB, LoopBB); 966 } 967 968 // Enter the loop. 969 EmitBlock(LoopBB); 970 971 // Set up the current-element phi. 972 llvm::PHINode *CurPtrPhi = 973 Builder.CreatePHI(CurPtr->getType(), 2, "array.cur"); 974 CurPtrPhi->addIncoming(CurPtr, EntryBB); 975 CurPtr = CurPtrPhi; 976 977 // Store the new Cleanup position for irregular Cleanups. 978 if (EndOfInit) Builder.CreateStore(CurPtr, EndOfInit); 979 980 // Enter a partial-destruction Cleanup if necessary. 981 if (!CleanupDominator && needsEHCleanup(DtorKind)) { 982 pushRegularPartialArrayCleanup(BeginPtr, CurPtr, ElementType, 983 getDestroyer(DtorKind)); 984 Cleanup = EHStack.stable_begin(); 985 CleanupDominator = Builder.CreateUnreachable(); 986 } 987 988 // Emit the initializer into this element. 989 StoreAnyExprIntoOneUnit(*this, Init, Init->getType(), CurPtr); 990 991 // Leave the Cleanup if we entered one. 992 if (CleanupDominator) { 993 DeactivateCleanupBlock(Cleanup, CleanupDominator); 994 CleanupDominator->eraseFromParent(); 995 } 996 997 // Advance to the next element by adjusting the pointer type as necessary. 998 llvm::Value *NextPtr = 999 Builder.CreateConstInBoundsGEP1_32(CurPtr, 1, "array.next"); 1000 1001 // Check whether we've gotten to the end of the array and, if so, 1002 // exit the loop. 1003 llvm::Value *IsEnd = Builder.CreateICmpEQ(NextPtr, EndPtr, "array.atend"); 1004 Builder.CreateCondBr(IsEnd, ContBB, LoopBB); 1005 CurPtrPhi->addIncoming(NextPtr, Builder.GetInsertBlock()); 1006 1007 EmitBlock(ContBB); 1008} 1009 1010static void EmitNewInitializer(CodeGenFunction &CGF, const CXXNewExpr *E, 1011 QualType ElementType, 1012 llvm::Value *NewPtr, 1013 llvm::Value *NumElements, 1014 llvm::Value *AllocSizeWithoutCookie) { 1015 if (E->isArray()) 1016 CGF.EmitNewArrayInitializer(E, ElementType, NewPtr, NumElements, 1017 AllocSizeWithoutCookie); 1018 else if (const Expr *Init = E->getInitializer()) 1019 StoreAnyExprIntoOneUnit(CGF, Init, E->getAllocatedType(), NewPtr); 1020} 1021 1022/// Emit a call to an operator new or operator delete function, as implicitly 1023/// created by new-expressions and delete-expressions. 1024static RValue EmitNewDeleteCall(CodeGenFunction &CGF, 1025 const FunctionDecl *Callee, 1026 const FunctionProtoType *CalleeType, 1027 const CallArgList &Args) { 1028 llvm::Instruction *CallOrInvoke; 1029 llvm::Value *CalleeAddr = CGF.CGM.GetAddrOfFunction(Callee); 1030 RValue RV = 1031 CGF.EmitCall(CGF.CGM.getTypes().arrangeFreeFunctionCall(Args, CalleeType), 1032 CalleeAddr, ReturnValueSlot(), Args, 1033 Callee, &CallOrInvoke); 1034 1035 /// C++1y [expr.new]p10: 1036 /// [In a new-expression,] an implementation is allowed to omit a call 1037 /// to a replaceable global allocation function. 1038 /// 1039 /// We model such elidable calls with the 'builtin' attribute. 1040 llvm::Function *Fn = dyn_cast<llvm::Function>(CalleeAddr); 1041 if (Callee->isReplaceableGlobalAllocationFunction() && 1042 Fn && Fn->hasFnAttribute(llvm::Attribute::NoBuiltin)) { 1043 // FIXME: Add addAttribute to CallSite. 1044 if (llvm::CallInst *CI = dyn_cast<llvm::CallInst>(CallOrInvoke)) 1045 CI->addAttribute(llvm::AttributeSet::FunctionIndex, 1046 llvm::Attribute::Builtin); 1047 else if (llvm::InvokeInst *II = dyn_cast<llvm::InvokeInst>(CallOrInvoke)) 1048 II->addAttribute(llvm::AttributeSet::FunctionIndex, 1049 llvm::Attribute::Builtin); 1050 else 1051 llvm_unreachable("unexpected kind of call instruction"); 1052 } 1053 1054 return RV; 1055} 1056 1057RValue CodeGenFunction::EmitBuiltinNewDeleteCall(const FunctionProtoType *Type, 1058 const Expr *Arg, 1059 bool IsDelete) { 1060 CallArgList Args; 1061 const Stmt *ArgS = Arg; 1062 EmitCallArgs(Args, *Type->param_type_begin(), 1063 ConstExprIterator(&ArgS), ConstExprIterator(&ArgS + 1)); 1064 // Find the allocation or deallocation function that we're calling. 1065 ASTContext &Ctx = getContext(); 1066 DeclarationName Name = Ctx.DeclarationNames 1067 .getCXXOperatorName(IsDelete ? OO_Delete : OO_New); 1068 for (auto *Decl : Ctx.getTranslationUnitDecl()->lookup(Name)) 1069 if (auto *FD = dyn_cast<FunctionDecl>(Decl)) 1070 if (Ctx.hasSameType(FD->getType(), QualType(Type, 0))) 1071 return EmitNewDeleteCall(*this, cast<FunctionDecl>(Decl), Type, Args); 1072 llvm_unreachable("predeclared global operator new/delete is missing"); 1073} 1074 1075namespace { 1076 /// A cleanup to call the given 'operator delete' function upon 1077 /// abnormal exit from a new expression. 1078 class CallDeleteDuringNew : public EHScopeStack::Cleanup { 1079 size_t NumPlacementArgs; 1080 const FunctionDecl *OperatorDelete; 1081 llvm::Value *Ptr; 1082 llvm::Value *AllocSize; 1083 1084 RValue *getPlacementArgs() { return reinterpret_cast<RValue*>(this+1); } 1085 1086 public: 1087 static size_t getExtraSize(size_t NumPlacementArgs) { 1088 return NumPlacementArgs * sizeof(RValue); 1089 } 1090 1091 CallDeleteDuringNew(size_t NumPlacementArgs, 1092 const FunctionDecl *OperatorDelete, 1093 llvm::Value *Ptr, 1094 llvm::Value *AllocSize) 1095 : NumPlacementArgs(NumPlacementArgs), OperatorDelete(OperatorDelete), 1096 Ptr(Ptr), AllocSize(AllocSize) {} 1097 1098 void setPlacementArg(unsigned I, RValue Arg) { 1099 assert(I < NumPlacementArgs && "index out of range"); 1100 getPlacementArgs()[I] = Arg; 1101 } 1102 1103 void Emit(CodeGenFunction &CGF, Flags flags) override { 1104 const FunctionProtoType *FPT 1105 = OperatorDelete->getType()->getAs<FunctionProtoType>(); 1106 assert(FPT->getNumParams() == NumPlacementArgs + 1 || 1107 (FPT->getNumParams() == 2 && NumPlacementArgs == 0)); 1108 1109 CallArgList DeleteArgs; 1110 1111 // The first argument is always a void*. 1112 FunctionProtoType::param_type_iterator AI = FPT->param_type_begin(); 1113 DeleteArgs.add(RValue::get(Ptr), *AI++); 1114 1115 // A member 'operator delete' can take an extra 'size_t' argument. 1116 if (FPT->getNumParams() == NumPlacementArgs + 2) 1117 DeleteArgs.add(RValue::get(AllocSize), *AI++); 1118 1119 // Pass the rest of the arguments, which must match exactly. 1120 for (unsigned I = 0; I != NumPlacementArgs; ++I) 1121 DeleteArgs.add(getPlacementArgs()[I], *AI++); 1122 1123 // Call 'operator delete'. 1124 EmitNewDeleteCall(CGF, OperatorDelete, FPT, DeleteArgs); 1125 } 1126 }; 1127 1128 /// A cleanup to call the given 'operator delete' function upon 1129 /// abnormal exit from a new expression when the new expression is 1130 /// conditional. 1131 class CallDeleteDuringConditionalNew : public EHScopeStack::Cleanup { 1132 size_t NumPlacementArgs; 1133 const FunctionDecl *OperatorDelete; 1134 DominatingValue<RValue>::saved_type Ptr; 1135 DominatingValue<RValue>::saved_type AllocSize; 1136 1137 DominatingValue<RValue>::saved_type *getPlacementArgs() { 1138 return reinterpret_cast<DominatingValue<RValue>::saved_type*>(this+1); 1139 } 1140 1141 public: 1142 static size_t getExtraSize(size_t NumPlacementArgs) { 1143 return NumPlacementArgs * sizeof(DominatingValue<RValue>::saved_type); 1144 } 1145 1146 CallDeleteDuringConditionalNew(size_t NumPlacementArgs, 1147 const FunctionDecl *OperatorDelete, 1148 DominatingValue<RValue>::saved_type Ptr, 1149 DominatingValue<RValue>::saved_type AllocSize) 1150 : NumPlacementArgs(NumPlacementArgs), OperatorDelete(OperatorDelete), 1151 Ptr(Ptr), AllocSize(AllocSize) {} 1152 1153 void setPlacementArg(unsigned I, DominatingValue<RValue>::saved_type Arg) { 1154 assert(I < NumPlacementArgs && "index out of range"); 1155 getPlacementArgs()[I] = Arg; 1156 } 1157 1158 void Emit(CodeGenFunction &CGF, Flags flags) override { 1159 const FunctionProtoType *FPT 1160 = OperatorDelete->getType()->getAs<FunctionProtoType>(); 1161 assert(FPT->getNumParams() == NumPlacementArgs + 1 || 1162 (FPT->getNumParams() == 2 && NumPlacementArgs == 0)); 1163 1164 CallArgList DeleteArgs; 1165 1166 // The first argument is always a void*. 1167 FunctionProtoType::param_type_iterator AI = FPT->param_type_begin(); 1168 DeleteArgs.add(Ptr.restore(CGF), *AI++); 1169 1170 // A member 'operator delete' can take an extra 'size_t' argument. 1171 if (FPT->getNumParams() == NumPlacementArgs + 2) { 1172 RValue RV = AllocSize.restore(CGF); 1173 DeleteArgs.add(RV, *AI++); 1174 } 1175 1176 // Pass the rest of the arguments, which must match exactly. 1177 for (unsigned I = 0; I != NumPlacementArgs; ++I) { 1178 RValue RV = getPlacementArgs()[I].restore(CGF); 1179 DeleteArgs.add(RV, *AI++); 1180 } 1181 1182 // Call 'operator delete'. 1183 EmitNewDeleteCall(CGF, OperatorDelete, FPT, DeleteArgs); 1184 } 1185 }; 1186} 1187 1188/// Enter a cleanup to call 'operator delete' if the initializer in a 1189/// new-expression throws. 1190static void EnterNewDeleteCleanup(CodeGenFunction &CGF, 1191 const CXXNewExpr *E, 1192 llvm::Value *NewPtr, 1193 llvm::Value *AllocSize, 1194 const CallArgList &NewArgs) { 1195 // If we're not inside a conditional branch, then the cleanup will 1196 // dominate and we can do the easier (and more efficient) thing. 1197 if (!CGF.isInConditionalBranch()) { 1198 CallDeleteDuringNew *Cleanup = CGF.EHStack 1199 .pushCleanupWithExtra<CallDeleteDuringNew>(EHCleanup, 1200 E->getNumPlacementArgs(), 1201 E->getOperatorDelete(), 1202 NewPtr, AllocSize); 1203 for (unsigned I = 0, N = E->getNumPlacementArgs(); I != N; ++I) 1204 Cleanup->setPlacementArg(I, NewArgs[I+1].RV); 1205 1206 return; 1207 } 1208 1209 // Otherwise, we need to save all this stuff. 1210 DominatingValue<RValue>::saved_type SavedNewPtr = 1211 DominatingValue<RValue>::save(CGF, RValue::get(NewPtr)); 1212 DominatingValue<RValue>::saved_type SavedAllocSize = 1213 DominatingValue<RValue>::save(CGF, RValue::get(AllocSize)); 1214 1215 CallDeleteDuringConditionalNew *Cleanup = CGF.EHStack 1216 .pushCleanupWithExtra<CallDeleteDuringConditionalNew>(EHCleanup, 1217 E->getNumPlacementArgs(), 1218 E->getOperatorDelete(), 1219 SavedNewPtr, 1220 SavedAllocSize); 1221 for (unsigned I = 0, N = E->getNumPlacementArgs(); I != N; ++I) 1222 Cleanup->setPlacementArg(I, 1223 DominatingValue<RValue>::save(CGF, NewArgs[I+1].RV)); 1224 1225 CGF.initFullExprCleanup(); 1226} 1227 1228llvm::Value *CodeGenFunction::EmitCXXNewExpr(const CXXNewExpr *E) { 1229 // The element type being allocated. 1230 QualType allocType = getContext().getBaseElementType(E->getAllocatedType()); 1231 1232 // 1. Build a call to the allocation function. 1233 FunctionDecl *allocator = E->getOperatorNew(); 1234 const FunctionProtoType *allocatorType = 1235 allocator->getType()->castAs<FunctionProtoType>(); 1236 1237 CallArgList allocatorArgs; 1238 1239 // The allocation size is the first argument. 1240 QualType sizeType = getContext().getSizeType(); 1241 1242 // If there is a brace-initializer, cannot allocate fewer elements than inits. 1243 unsigned minElements = 0; 1244 if (E->isArray() && E->hasInitializer()) { 1245 if (const InitListExpr *ILE = dyn_cast<InitListExpr>(E->getInitializer())) 1246 minElements = ILE->getNumInits(); 1247 } 1248 1249 llvm::Value *numElements = nullptr; 1250 llvm::Value *allocSizeWithoutCookie = nullptr; 1251 llvm::Value *allocSize = 1252 EmitCXXNewAllocSize(*this, E, minElements, numElements, 1253 allocSizeWithoutCookie); 1254 1255 allocatorArgs.add(RValue::get(allocSize), sizeType); 1256 1257 // We start at 1 here because the first argument (the allocation size) 1258 // has already been emitted. 1259 EmitCallArgs(allocatorArgs, allocatorType, E->placement_arg_begin(), 1260 E->placement_arg_end(), /* CalleeDecl */ nullptr, 1261 /*ParamsToSkip*/ 1); 1262 1263 // Emit the allocation call. If the allocator is a global placement 1264 // operator, just "inline" it directly. 1265 RValue RV; 1266 if (allocator->isReservedGlobalPlacementOperator()) { 1267 assert(allocatorArgs.size() == 2); 1268 RV = allocatorArgs[1].RV; 1269 // TODO: kill any unnecessary computations done for the size 1270 // argument. 1271 } else { 1272 RV = EmitNewDeleteCall(*this, allocator, allocatorType, allocatorArgs); 1273 } 1274 1275 // Emit a null check on the allocation result if the allocation 1276 // function is allowed to return null (because it has a non-throwing 1277 // exception spec; for this part, we inline 1278 // CXXNewExpr::shouldNullCheckAllocation()) and we have an 1279 // interesting initializer. 1280 bool nullCheck = allocatorType->isNothrow(getContext()) && 1281 (!allocType.isPODType(getContext()) || E->hasInitializer()); 1282 1283 llvm::BasicBlock *nullCheckBB = nullptr; 1284 llvm::BasicBlock *contBB = nullptr; 1285 1286 llvm::Value *allocation = RV.getScalarVal(); 1287 unsigned AS = allocation->getType()->getPointerAddressSpace(); 1288 1289 // The null-check means that the initializer is conditionally 1290 // evaluated. 1291 ConditionalEvaluation conditional(*this); 1292 1293 if (nullCheck) { 1294 conditional.begin(*this); 1295 1296 nullCheckBB = Builder.GetInsertBlock(); 1297 llvm::BasicBlock *notNullBB = createBasicBlock("new.notnull"); 1298 contBB = createBasicBlock("new.cont"); 1299 1300 llvm::Value *isNull = Builder.CreateIsNull(allocation, "new.isnull"); 1301 Builder.CreateCondBr(isNull, contBB, notNullBB); 1302 EmitBlock(notNullBB); 1303 } 1304 1305 // If there's an operator delete, enter a cleanup to call it if an 1306 // exception is thrown. 1307 EHScopeStack::stable_iterator operatorDeleteCleanup; 1308 llvm::Instruction *cleanupDominator = nullptr; 1309 if (E->getOperatorDelete() && 1310 !E->getOperatorDelete()->isReservedGlobalPlacementOperator()) { 1311 EnterNewDeleteCleanup(*this, E, allocation, allocSize, allocatorArgs); 1312 operatorDeleteCleanup = EHStack.stable_begin(); 1313 cleanupDominator = Builder.CreateUnreachable(); 1314 } 1315 1316 assert((allocSize == allocSizeWithoutCookie) == 1317 CalculateCookiePadding(*this, E).isZero()); 1318 if (allocSize != allocSizeWithoutCookie) { 1319 assert(E->isArray()); 1320 allocation = CGM.getCXXABI().InitializeArrayCookie(*this, allocation, 1321 numElements, 1322 E, allocType); 1323 } 1324 1325 llvm::Type *elementPtrTy 1326 = ConvertTypeForMem(allocType)->getPointerTo(AS); 1327 llvm::Value *result = Builder.CreateBitCast(allocation, elementPtrTy); 1328 1329 EmitNewInitializer(*this, E, allocType, result, numElements, 1330 allocSizeWithoutCookie); 1331 if (E->isArray()) { 1332 // NewPtr is a pointer to the base element type. If we're 1333 // allocating an array of arrays, we'll need to cast back to the 1334 // array pointer type. 1335 llvm::Type *resultType = ConvertTypeForMem(E->getType()); 1336 if (result->getType() != resultType) 1337 result = Builder.CreateBitCast(result, resultType); 1338 } 1339 1340 // Deactivate the 'operator delete' cleanup if we finished 1341 // initialization. 1342 if (operatorDeleteCleanup.isValid()) { 1343 DeactivateCleanupBlock(operatorDeleteCleanup, cleanupDominator); 1344 cleanupDominator->eraseFromParent(); 1345 } 1346 1347 if (nullCheck) { 1348 conditional.end(*this); 1349 1350 llvm::BasicBlock *notNullBB = Builder.GetInsertBlock(); 1351 EmitBlock(contBB); 1352 1353 llvm::PHINode *PHI = Builder.CreatePHI(result->getType(), 2); 1354 PHI->addIncoming(result, notNullBB); 1355 PHI->addIncoming(llvm::Constant::getNullValue(result->getType()), 1356 nullCheckBB); 1357 1358 result = PHI; 1359 } 1360 1361 return result; 1362} 1363 1364void CodeGenFunction::EmitDeleteCall(const FunctionDecl *DeleteFD, 1365 llvm::Value *Ptr, 1366 QualType DeleteTy) { 1367 assert(DeleteFD->getOverloadedOperator() == OO_Delete); 1368 1369 const FunctionProtoType *DeleteFTy = 1370 DeleteFD->getType()->getAs<FunctionProtoType>(); 1371 1372 CallArgList DeleteArgs; 1373 1374 // Check if we need to pass the size to the delete operator. 1375 llvm::Value *Size = nullptr; 1376 QualType SizeTy; 1377 if (DeleteFTy->getNumParams() == 2) { 1378 SizeTy = DeleteFTy->getParamType(1); 1379 CharUnits DeleteTypeSize = getContext().getTypeSizeInChars(DeleteTy); 1380 Size = llvm::ConstantInt::get(ConvertType(SizeTy), 1381 DeleteTypeSize.getQuantity()); 1382 } 1383 1384 QualType ArgTy = DeleteFTy->getParamType(0); 1385 llvm::Value *DeletePtr = Builder.CreateBitCast(Ptr, ConvertType(ArgTy)); 1386 DeleteArgs.add(RValue::get(DeletePtr), ArgTy); 1387 1388 if (Size) 1389 DeleteArgs.add(RValue::get(Size), SizeTy); 1390 1391 // Emit the call to delete. 1392 EmitNewDeleteCall(*this, DeleteFD, DeleteFTy, DeleteArgs); 1393} 1394 1395namespace { 1396 /// Calls the given 'operator delete' on a single object. 1397 struct CallObjectDelete : EHScopeStack::Cleanup { 1398 llvm::Value *Ptr; 1399 const FunctionDecl *OperatorDelete; 1400 QualType ElementType; 1401 1402 CallObjectDelete(llvm::Value *Ptr, 1403 const FunctionDecl *OperatorDelete, 1404 QualType ElementType) 1405 : Ptr(Ptr), OperatorDelete(OperatorDelete), ElementType(ElementType) {} 1406 1407 void Emit(CodeGenFunction &CGF, Flags flags) override { 1408 CGF.EmitDeleteCall(OperatorDelete, Ptr, ElementType); 1409 } 1410 }; 1411} 1412 1413void 1414CodeGenFunction::pushCallObjectDeleteCleanup(const FunctionDecl *OperatorDelete, 1415 llvm::Value *CompletePtr, 1416 QualType ElementType) { 1417 EHStack.pushCleanup<CallObjectDelete>(NormalAndEHCleanup, CompletePtr, 1418 OperatorDelete, ElementType); 1419} 1420 1421/// Emit the code for deleting a single object. 1422static void EmitObjectDelete(CodeGenFunction &CGF, 1423 const CXXDeleteExpr *DE, 1424 llvm::Value *Ptr, 1425 QualType ElementType) { 1426 // Find the destructor for the type, if applicable. If the 1427 // destructor is virtual, we'll just emit the vcall and return. 1428 const CXXDestructorDecl *Dtor = nullptr; 1429 if (const RecordType *RT = ElementType->getAs<RecordType>()) { 1430 CXXRecordDecl *RD = cast<CXXRecordDecl>(RT->getDecl()); 1431 if (RD->hasDefinition() && !RD->hasTrivialDestructor()) { 1432 Dtor = RD->getDestructor(); 1433 1434 if (Dtor->isVirtual()) { 1435 CGF.CGM.getCXXABI().emitVirtualObjectDelete(CGF, DE, Ptr, ElementType, 1436 Dtor); 1437 return; 1438 } 1439 } 1440 } 1441 1442 // Make sure that we call delete even if the dtor throws. 1443 // This doesn't have to a conditional cleanup because we're going 1444 // to pop it off in a second. 1445 const FunctionDecl *OperatorDelete = DE->getOperatorDelete(); 1446 CGF.EHStack.pushCleanup<CallObjectDelete>(NormalAndEHCleanup, 1447 Ptr, OperatorDelete, ElementType); 1448 1449 if (Dtor) 1450 CGF.EmitCXXDestructorCall(Dtor, Dtor_Complete, 1451 /*ForVirtualBase=*/false, 1452 /*Delegating=*/false, 1453 Ptr); 1454 else if (CGF.getLangOpts().ObjCAutoRefCount && 1455 ElementType->isObjCLifetimeType()) { 1456 switch (ElementType.getObjCLifetime()) { 1457 case Qualifiers::OCL_None: 1458 case Qualifiers::OCL_ExplicitNone: 1459 case Qualifiers::OCL_Autoreleasing: 1460 break; 1461 1462 case Qualifiers::OCL_Strong: { 1463 // Load the pointer value. 1464 llvm::Value *PtrValue = CGF.Builder.CreateLoad(Ptr, 1465 ElementType.isVolatileQualified()); 1466 1467 CGF.EmitARCRelease(PtrValue, ARCPreciseLifetime); 1468 break; 1469 } 1470 1471 case Qualifiers::OCL_Weak: 1472 CGF.EmitARCDestroyWeak(Ptr); 1473 break; 1474 } 1475 } 1476 1477 CGF.PopCleanupBlock(); 1478} 1479 1480namespace { 1481 /// Calls the given 'operator delete' on an array of objects. 1482 struct CallArrayDelete : EHScopeStack::Cleanup { 1483 llvm::Value *Ptr; 1484 const FunctionDecl *OperatorDelete; 1485 llvm::Value *NumElements; 1486 QualType ElementType; 1487 CharUnits CookieSize; 1488 1489 CallArrayDelete(llvm::Value *Ptr, 1490 const FunctionDecl *OperatorDelete, 1491 llvm::Value *NumElements, 1492 QualType ElementType, 1493 CharUnits CookieSize) 1494 : Ptr(Ptr), OperatorDelete(OperatorDelete), NumElements(NumElements), 1495 ElementType(ElementType), CookieSize(CookieSize) {} 1496 1497 void Emit(CodeGenFunction &CGF, Flags flags) override { 1498 const FunctionProtoType *DeleteFTy = 1499 OperatorDelete->getType()->getAs<FunctionProtoType>(); 1500 assert(DeleteFTy->getNumParams() == 1 || DeleteFTy->getNumParams() == 2); 1501 1502 CallArgList Args; 1503 1504 // Pass the pointer as the first argument. 1505 QualType VoidPtrTy = DeleteFTy->getParamType(0); 1506 llvm::Value *DeletePtr 1507 = CGF.Builder.CreateBitCast(Ptr, CGF.ConvertType(VoidPtrTy)); 1508 Args.add(RValue::get(DeletePtr), VoidPtrTy); 1509 1510 // Pass the original requested size as the second argument. 1511 if (DeleteFTy->getNumParams() == 2) { 1512 QualType size_t = DeleteFTy->getParamType(1); 1513 llvm::IntegerType *SizeTy 1514 = cast<llvm::IntegerType>(CGF.ConvertType(size_t)); 1515 1516 CharUnits ElementTypeSize = 1517 CGF.CGM.getContext().getTypeSizeInChars(ElementType); 1518 1519 // The size of an element, multiplied by the number of elements. 1520 llvm::Value *Size 1521 = llvm::ConstantInt::get(SizeTy, ElementTypeSize.getQuantity()); 1522 Size = CGF.Builder.CreateMul(Size, NumElements); 1523 1524 // Plus the size of the cookie if applicable. 1525 if (!CookieSize.isZero()) { 1526 llvm::Value *CookieSizeV 1527 = llvm::ConstantInt::get(SizeTy, CookieSize.getQuantity()); 1528 Size = CGF.Builder.CreateAdd(Size, CookieSizeV); 1529 } 1530 1531 Args.add(RValue::get(Size), size_t); 1532 } 1533 1534 // Emit the call to delete. 1535 EmitNewDeleteCall(CGF, OperatorDelete, DeleteFTy, Args); 1536 } 1537 }; 1538} 1539 1540/// Emit the code for deleting an array of objects. 1541static void EmitArrayDelete(CodeGenFunction &CGF, 1542 const CXXDeleteExpr *E, 1543 llvm::Value *deletedPtr, 1544 QualType elementType) { 1545 llvm::Value *numElements = nullptr; 1546 llvm::Value *allocatedPtr = nullptr; 1547 CharUnits cookieSize; 1548 CGF.CGM.getCXXABI().ReadArrayCookie(CGF, deletedPtr, E, elementType, 1549 numElements, allocatedPtr, cookieSize); 1550 1551 assert(allocatedPtr && "ReadArrayCookie didn't set allocated pointer"); 1552 1553 // Make sure that we call delete even if one of the dtors throws. 1554 const FunctionDecl *operatorDelete = E->getOperatorDelete(); 1555 CGF.EHStack.pushCleanup<CallArrayDelete>(NormalAndEHCleanup, 1556 allocatedPtr, operatorDelete, 1557 numElements, elementType, 1558 cookieSize); 1559 1560 // Destroy the elements. 1561 if (QualType::DestructionKind dtorKind = elementType.isDestructedType()) { 1562 assert(numElements && "no element count for a type with a destructor!"); 1563 1564 llvm::Value *arrayEnd = 1565 CGF.Builder.CreateInBoundsGEP(deletedPtr, numElements, "delete.end"); 1566 1567 // Note that it is legal to allocate a zero-length array, and we 1568 // can never fold the check away because the length should always 1569 // come from a cookie. 1570 CGF.emitArrayDestroy(deletedPtr, arrayEnd, elementType, 1571 CGF.getDestroyer(dtorKind), 1572 /*checkZeroLength*/ true, 1573 CGF.needsEHCleanup(dtorKind)); 1574 } 1575 1576 // Pop the cleanup block. 1577 CGF.PopCleanupBlock(); 1578} 1579 1580void CodeGenFunction::EmitCXXDeleteExpr(const CXXDeleteExpr *E) { 1581 const Expr *Arg = E->getArgument(); 1582 llvm::Value *Ptr = EmitScalarExpr(Arg); 1583 1584 // Null check the pointer. 1585 llvm::BasicBlock *DeleteNotNull = createBasicBlock("delete.notnull"); 1586 llvm::BasicBlock *DeleteEnd = createBasicBlock("delete.end"); 1587 1588 llvm::Value *IsNull = Builder.CreateIsNull(Ptr, "isnull"); 1589 1590 Builder.CreateCondBr(IsNull, DeleteEnd, DeleteNotNull); 1591 EmitBlock(DeleteNotNull); 1592 1593 // We might be deleting a pointer to array. If so, GEP down to the 1594 // first non-array element. 1595 // (this assumes that A(*)[3][7] is converted to [3 x [7 x %A]]*) 1596 QualType DeleteTy = Arg->getType()->getAs<PointerType>()->getPointeeType(); 1597 if (DeleteTy->isConstantArrayType()) { 1598 llvm::Value *Zero = Builder.getInt32(0); 1599 SmallVector<llvm::Value*,8> GEP; 1600 1601 GEP.push_back(Zero); // point at the outermost array 1602 1603 // For each layer of array type we're pointing at: 1604 while (const ConstantArrayType *Arr 1605 = getContext().getAsConstantArrayType(DeleteTy)) { 1606 // 1. Unpeel the array type. 1607 DeleteTy = Arr->getElementType(); 1608 1609 // 2. GEP to the first element of the array. 1610 GEP.push_back(Zero); 1611 } 1612 1613 Ptr = Builder.CreateInBoundsGEP(Ptr, GEP, "del.first"); 1614 } 1615 1616 assert(ConvertTypeForMem(DeleteTy) == 1617 cast<llvm::PointerType>(Ptr->getType())->getElementType()); 1618 1619 if (E->isArrayForm()) { 1620 EmitArrayDelete(*this, E, Ptr, DeleteTy); 1621 } else { 1622 EmitObjectDelete(*this, E, Ptr, DeleteTy); 1623 } 1624 1625 EmitBlock(DeleteEnd); 1626} 1627 1628static bool isGLValueFromPointerDeref(const Expr *E) { 1629 E = E->IgnoreParens(); 1630 1631 if (const auto *CE = dyn_cast<CastExpr>(E)) { 1632 if (!CE->getSubExpr()->isGLValue()) 1633 return false; 1634 return isGLValueFromPointerDeref(CE->getSubExpr()); 1635 } 1636 1637 if (const auto *OVE = dyn_cast<OpaqueValueExpr>(E)) 1638 return isGLValueFromPointerDeref(OVE->getSourceExpr()); 1639 1640 if (const auto *BO = dyn_cast<BinaryOperator>(E)) 1641 if (BO->getOpcode() == BO_Comma) 1642 return isGLValueFromPointerDeref(BO->getRHS()); 1643 1644 if (const auto *ACO = dyn_cast<AbstractConditionalOperator>(E)) 1645 return isGLValueFromPointerDeref(ACO->getTrueExpr()) || 1646 isGLValueFromPointerDeref(ACO->getFalseExpr()); 1647 1648 // C++11 [expr.sub]p1: 1649 // The expression E1[E2] is identical (by definition) to *((E1)+(E2)) 1650 if (isa<ArraySubscriptExpr>(E)) 1651 return true; 1652 1653 if (const auto *UO = dyn_cast<UnaryOperator>(E)) 1654 if (UO->getOpcode() == UO_Deref) 1655 return true; 1656 1657 return false; 1658} 1659 1660static llvm::Value *EmitTypeidFromVTable(CodeGenFunction &CGF, const Expr *E, 1661 llvm::Type *StdTypeInfoPtrTy) { 1662 // Get the vtable pointer. 1663 llvm::Value *ThisPtr = CGF.EmitLValue(E).getAddress(); 1664 1665 // C++ [expr.typeid]p2: 1666 // If the glvalue expression is obtained by applying the unary * operator to 1667 // a pointer and the pointer is a null pointer value, the typeid expression 1668 // throws the std::bad_typeid exception. 1669 // 1670 // However, this paragraph's intent is not clear. We choose a very generous 1671 // interpretation which implores us to consider comma operators, conditional 1672 // operators, parentheses and other such constructs. 1673 QualType SrcRecordTy = E->getType(); 1674 if (CGF.CGM.getCXXABI().shouldTypeidBeNullChecked( 1675 isGLValueFromPointerDeref(E), SrcRecordTy)) { 1676 llvm::BasicBlock *BadTypeidBlock = 1677 CGF.createBasicBlock("typeid.bad_typeid"); 1678 llvm::BasicBlock *EndBlock = CGF.createBasicBlock("typeid.end"); 1679 1680 llvm::Value *IsNull = CGF.Builder.CreateIsNull(ThisPtr); 1681 CGF.Builder.CreateCondBr(IsNull, BadTypeidBlock, EndBlock); 1682 1683 CGF.EmitBlock(BadTypeidBlock); 1684 CGF.CGM.getCXXABI().EmitBadTypeidCall(CGF); 1685 CGF.EmitBlock(EndBlock); 1686 } 1687 1688 return CGF.CGM.getCXXABI().EmitTypeid(CGF, SrcRecordTy, ThisPtr, 1689 StdTypeInfoPtrTy); 1690} 1691 1692llvm::Value *CodeGenFunction::EmitCXXTypeidExpr(const CXXTypeidExpr *E) { 1693 llvm::Type *StdTypeInfoPtrTy = 1694 ConvertType(E->getType())->getPointerTo(); 1695 1696 if (E->isTypeOperand()) { 1697 llvm::Constant *TypeInfo = 1698 CGM.GetAddrOfRTTIDescriptor(E->getTypeOperand(getContext())); 1699 return Builder.CreateBitCast(TypeInfo, StdTypeInfoPtrTy); 1700 } 1701 1702 // C++ [expr.typeid]p2: 1703 // When typeid is applied to a glvalue expression whose type is a 1704 // polymorphic class type, the result refers to a std::type_info object 1705 // representing the type of the most derived object (that is, the dynamic 1706 // type) to which the glvalue refers. 1707 if (E->isPotentiallyEvaluated()) 1708 return EmitTypeidFromVTable(*this, E->getExprOperand(), 1709 StdTypeInfoPtrTy); 1710 1711 QualType OperandTy = E->getExprOperand()->getType(); 1712 return Builder.CreateBitCast(CGM.GetAddrOfRTTIDescriptor(OperandTy), 1713 StdTypeInfoPtrTy); 1714} 1715 1716static llvm::Value *EmitDynamicCastToNull(CodeGenFunction &CGF, 1717 QualType DestTy) { 1718 llvm::Type *DestLTy = CGF.ConvertType(DestTy); 1719 if (DestTy->isPointerType()) 1720 return llvm::Constant::getNullValue(DestLTy); 1721 1722 /// C++ [expr.dynamic.cast]p9: 1723 /// A failed cast to reference type throws std::bad_cast 1724 if (!CGF.CGM.getCXXABI().EmitBadCastCall(CGF)) 1725 return nullptr; 1726 1727 CGF.EmitBlock(CGF.createBasicBlock("dynamic_cast.end")); 1728 return llvm::UndefValue::get(DestLTy); 1729} 1730 1731llvm::Value *CodeGenFunction::EmitDynamicCast(llvm::Value *Value, 1732 const CXXDynamicCastExpr *DCE) { 1733 QualType DestTy = DCE->getTypeAsWritten(); 1734 1735 if (DCE->isAlwaysNull()) 1736 if (llvm::Value *T = EmitDynamicCastToNull(*this, DestTy)) 1737 return T; 1738 1739 QualType SrcTy = DCE->getSubExpr()->getType(); 1740 1741 // C++ [expr.dynamic.cast]p7: 1742 // If T is "pointer to cv void," then the result is a pointer to the most 1743 // derived object pointed to by v. 1744 const PointerType *DestPTy = DestTy->getAs<PointerType>(); 1745 1746 bool isDynamicCastToVoid; 1747 QualType SrcRecordTy; 1748 QualType DestRecordTy; 1749 if (DestPTy) { 1750 isDynamicCastToVoid = DestPTy->getPointeeType()->isVoidType(); 1751 SrcRecordTy = SrcTy->castAs<PointerType>()->getPointeeType(); 1752 DestRecordTy = DestPTy->getPointeeType(); 1753 } else { 1754 isDynamicCastToVoid = false; 1755 SrcRecordTy = SrcTy; 1756 DestRecordTy = DestTy->castAs<ReferenceType>()->getPointeeType(); 1757 } 1758 1759 assert(SrcRecordTy->isRecordType() && "source type must be a record type!"); 1760 1761 // C++ [expr.dynamic.cast]p4: 1762 // If the value of v is a null pointer value in the pointer case, the result 1763 // is the null pointer value of type T. 1764 bool ShouldNullCheckSrcValue = 1765 CGM.getCXXABI().shouldDynamicCastCallBeNullChecked(SrcTy->isPointerType(), 1766 SrcRecordTy); 1767 1768 llvm::BasicBlock *CastNull = nullptr; 1769 llvm::BasicBlock *CastNotNull = nullptr; 1770 llvm::BasicBlock *CastEnd = createBasicBlock("dynamic_cast.end"); 1771 1772 if (ShouldNullCheckSrcValue) { 1773 CastNull = createBasicBlock("dynamic_cast.null"); 1774 CastNotNull = createBasicBlock("dynamic_cast.notnull"); 1775 1776 llvm::Value *IsNull = Builder.CreateIsNull(Value); 1777 Builder.CreateCondBr(IsNull, CastNull, CastNotNull); 1778 EmitBlock(CastNotNull); 1779 } 1780 1781 if (isDynamicCastToVoid) { 1782 Value = CGM.getCXXABI().EmitDynamicCastToVoid(*this, Value, SrcRecordTy, 1783 DestTy); 1784 } else { 1785 assert(DestRecordTy->isRecordType() && 1786 "destination type must be a record type!"); 1787 Value = CGM.getCXXABI().EmitDynamicCastCall(*this, Value, SrcRecordTy, 1788 DestTy, DestRecordTy, CastEnd); 1789 } 1790 1791 if (ShouldNullCheckSrcValue) { 1792 EmitBranch(CastEnd); 1793 1794 EmitBlock(CastNull); 1795 EmitBranch(CastEnd); 1796 } 1797 1798 EmitBlock(CastEnd); 1799 1800 if (ShouldNullCheckSrcValue) { 1801 llvm::PHINode *PHI = Builder.CreatePHI(Value->getType(), 2); 1802 PHI->addIncoming(Value, CastNotNull); 1803 PHI->addIncoming(llvm::Constant::getNullValue(Value->getType()), CastNull); 1804 1805 Value = PHI; 1806 } 1807 1808 return Value; 1809} 1810 1811void CodeGenFunction::EmitLambdaExpr(const LambdaExpr *E, AggValueSlot Slot) { 1812 RunCleanupsScope Scope(*this); 1813 LValue SlotLV = 1814 MakeAddrLValue(Slot.getAddr(), E->getType(), Slot.getAlignment()); 1815 1816 CXXRecordDecl::field_iterator CurField = E->getLambdaClass()->field_begin(); 1817 for (LambdaExpr::capture_init_iterator i = E->capture_init_begin(), 1818 e = E->capture_init_end(); 1819 i != e; ++i, ++CurField) { 1820 // Emit initialization 1821 LValue LV = EmitLValueForFieldInitialization(SlotLV, *CurField); 1822 if (CurField->hasCapturedVLAType()) { 1823 auto VAT = CurField->getCapturedVLAType(); 1824 EmitStoreThroughLValue(RValue::get(VLASizeMap[VAT->getSizeExpr()]), LV); 1825 } else { 1826 ArrayRef<VarDecl *> ArrayIndexes; 1827 if (CurField->getType()->isArrayType()) 1828 ArrayIndexes = E->getCaptureInitIndexVars(i); 1829 EmitInitializerForField(*CurField, LV, *i, ArrayIndexes); 1830 } 1831 } 1832} 1833