CGExprCXX.cpp revision 263508
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/Intrinsics.h" 22#include "llvm/Support/CallSite.h" 23 24using namespace clang; 25using namespace CodeGen; 26 27RValue CodeGenFunction::EmitCXXMemberCall(const CXXMethodDecl *MD, 28 SourceLocation CallLoc, 29 llvm::Value *Callee, 30 ReturnValueSlot ReturnValue, 31 llvm::Value *This, 32 llvm::Value *ImplicitParam, 33 QualType ImplicitParamTy, 34 CallExpr::const_arg_iterator ArgBeg, 35 CallExpr::const_arg_iterator ArgEnd) { 36 assert(MD->isInstance() && 37 "Trying to emit a member call expr on a static method!"); 38 39 // C++11 [class.mfct.non-static]p2: 40 // If a non-static member function of a class X is called for an object that 41 // is not of type X, or of a type derived from X, the behavior is undefined. 42 EmitTypeCheck(isa<CXXConstructorDecl>(MD) ? TCK_ConstructorCall 43 : TCK_MemberCall, 44 CallLoc, This, getContext().getRecordType(MD->getParent())); 45 46 CallArgList Args; 47 48 // Push the this ptr. 49 Args.add(RValue::get(This), MD->getThisType(getContext())); 50 51 // If there is an implicit parameter (e.g. VTT), emit it. 52 if (ImplicitParam) { 53 Args.add(RValue::get(ImplicitParam), ImplicitParamTy); 54 } 55 56 const FunctionProtoType *FPT = MD->getType()->castAs<FunctionProtoType>(); 57 RequiredArgs required = RequiredArgs::forPrototypePlus(FPT, Args.size()); 58 59 // And the rest of the call args. 60 EmitCallArgs(Args, FPT, ArgBeg, ArgEnd); 61 62 return EmitCall(CGM.getTypes().arrangeCXXMethodCall(Args, FPT, required), 63 Callee, ReturnValue, Args, MD); 64} 65 66static CXXRecordDecl *getCXXRecord(const Expr *E) { 67 QualType T = E->getType(); 68 if (const PointerType *PTy = T->getAs<PointerType>()) 69 T = PTy->getPointeeType(); 70 const RecordType *Ty = T->castAs<RecordType>(); 71 return cast<CXXRecordDecl>(Ty->getDecl()); 72} 73 74// Note: This function also emit constructor calls to support a MSVC 75// extensions allowing explicit constructor function call. 76RValue CodeGenFunction::EmitCXXMemberCallExpr(const CXXMemberCallExpr *CE, 77 ReturnValueSlot ReturnValue) { 78 const Expr *callee = CE->getCallee()->IgnoreParens(); 79 80 if (isa<BinaryOperator>(callee)) 81 return EmitCXXMemberPointerCallExpr(CE, ReturnValue); 82 83 const MemberExpr *ME = cast<MemberExpr>(callee); 84 const CXXMethodDecl *MD = cast<CXXMethodDecl>(ME->getMemberDecl()); 85 86 if (MD->isStatic()) { 87 // The method is static, emit it as we would a regular call. 88 llvm::Value *Callee = CGM.GetAddrOfFunction(MD); 89 return EmitCall(getContext().getPointerType(MD->getType()), Callee, 90 CE->getLocStart(), ReturnValue, CE->arg_begin(), 91 CE->arg_end()); 92 } 93 94 // Compute the object pointer. 95 const Expr *Base = ME->getBase(); 96 bool CanUseVirtualCall = MD->isVirtual() && !ME->hasQualifier(); 97 98 const CXXMethodDecl *DevirtualizedMethod = NULL; 99 if (CanUseVirtualCall && CanDevirtualizeMemberFunctionCall(Base, MD)) { 100 const CXXRecordDecl *BestDynamicDecl = Base->getBestDynamicClassType(); 101 DevirtualizedMethod = MD->getCorrespondingMethodInClass(BestDynamicDecl); 102 assert(DevirtualizedMethod); 103 const CXXRecordDecl *DevirtualizedClass = DevirtualizedMethod->getParent(); 104 const Expr *Inner = Base->ignoreParenBaseCasts(); 105 if (getCXXRecord(Inner) == DevirtualizedClass) 106 // If the class of the Inner expression is where the dynamic method 107 // is defined, build the this pointer from it. 108 Base = Inner; 109 else if (getCXXRecord(Base) != DevirtualizedClass) { 110 // If the method is defined in a class that is not the best dynamic 111 // one or the one of the full expression, we would have to build 112 // a derived-to-base cast to compute the correct this pointer, but 113 // we don't have support for that yet, so do a virtual call. 114 DevirtualizedMethod = NULL; 115 } 116 // If the return types are not the same, this might be a case where more 117 // code needs to run to compensate for it. For example, the derived 118 // method might return a type that inherits form from the return 119 // type of MD and has a prefix. 120 // For now we just avoid devirtualizing these covariant cases. 121 if (DevirtualizedMethod && 122 DevirtualizedMethod->getResultType().getCanonicalType() != 123 MD->getResultType().getCanonicalType()) 124 DevirtualizedMethod = NULL; 125 } 126 127 llvm::Value *This; 128 if (ME->isArrow()) 129 This = EmitScalarExpr(Base); 130 else 131 This = EmitLValue(Base).getAddress(); 132 133 134 if (MD->isTrivial()) { 135 if (isa<CXXDestructorDecl>(MD)) return RValue::get(0); 136 if (isa<CXXConstructorDecl>(MD) && 137 cast<CXXConstructorDecl>(MD)->isDefaultConstructor()) 138 return RValue::get(0); 139 140 if (MD->isCopyAssignmentOperator() || MD->isMoveAssignmentOperator()) { 141 // We don't like to generate the trivial copy/move assignment operator 142 // when it isn't necessary; just produce the proper effect here. 143 llvm::Value *RHS = EmitLValue(*CE->arg_begin()).getAddress(); 144 EmitAggregateAssign(This, RHS, CE->getType()); 145 return RValue::get(This); 146 } 147 148 if (isa<CXXConstructorDecl>(MD) && 149 cast<CXXConstructorDecl>(MD)->isCopyOrMoveConstructor()) { 150 // Trivial move and copy ctor are the same. 151 llvm::Value *RHS = EmitLValue(*CE->arg_begin()).getAddress(); 152 EmitSynthesizedCXXCopyCtorCall(cast<CXXConstructorDecl>(MD), This, RHS, 153 CE->arg_begin(), CE->arg_end()); 154 return RValue::get(This); 155 } 156 llvm_unreachable("unknown trivial member function"); 157 } 158 159 // Compute the function type we're calling. 160 const CXXMethodDecl *CalleeDecl = DevirtualizedMethod ? DevirtualizedMethod : MD; 161 const CGFunctionInfo *FInfo = 0; 162 if (const CXXDestructorDecl *Dtor = dyn_cast<CXXDestructorDecl>(CalleeDecl)) 163 FInfo = &CGM.getTypes().arrangeCXXDestructor(Dtor, 164 Dtor_Complete); 165 else if (const CXXConstructorDecl *Ctor = dyn_cast<CXXConstructorDecl>(CalleeDecl)) 166 FInfo = &CGM.getTypes().arrangeCXXConstructorDeclaration(Ctor, 167 Ctor_Complete); 168 else 169 FInfo = &CGM.getTypes().arrangeCXXMethodDeclaration(CalleeDecl); 170 171 llvm::FunctionType *Ty = CGM.getTypes().GetFunctionType(*FInfo); 172 173 // C++ [class.virtual]p12: 174 // Explicit qualification with the scope operator (5.1) suppresses the 175 // virtual call mechanism. 176 // 177 // We also don't emit a virtual call if the base expression has a record type 178 // because then we know what the type is. 179 bool UseVirtualCall = CanUseVirtualCall && !DevirtualizedMethod; 180 llvm::Value *Callee; 181 182 if (const CXXDestructorDecl *Dtor = dyn_cast<CXXDestructorDecl>(MD)) { 183 assert(CE->arg_begin() == CE->arg_end() && 184 "Destructor shouldn't have explicit parameters"); 185 assert(ReturnValue.isNull() && "Destructor shouldn't have return value"); 186 if (UseVirtualCall) { 187 CGM.getCXXABI().EmitVirtualDestructorCall(*this, Dtor, Dtor_Complete, 188 CE->getExprLoc(), This); 189 } else { 190 if (getLangOpts().AppleKext && 191 MD->isVirtual() && 192 ME->hasQualifier()) 193 Callee = BuildAppleKextVirtualCall(MD, ME->getQualifier(), Ty); 194 else if (!DevirtualizedMethod) 195 Callee = CGM.GetAddrOfCXXDestructor(Dtor, Dtor_Complete, FInfo, Ty); 196 else { 197 const CXXDestructorDecl *DDtor = 198 cast<CXXDestructorDecl>(DevirtualizedMethod); 199 Callee = CGM.GetAddrOfFunction(GlobalDecl(DDtor, Dtor_Complete), Ty); 200 } 201 EmitCXXMemberCall(MD, CE->getExprLoc(), Callee, ReturnValue, This, 202 /*ImplicitParam=*/0, QualType(), 0, 0); 203 } 204 return RValue::get(0); 205 } 206 207 if (const CXXConstructorDecl *Ctor = dyn_cast<CXXConstructorDecl>(MD)) { 208 Callee = CGM.GetAddrOfFunction(GlobalDecl(Ctor, Ctor_Complete), Ty); 209 } else if (UseVirtualCall) { 210 Callee = CGM.getCXXABI().getVirtualFunctionPointer(*this, MD, This, Ty); 211 } else { 212 if (getLangOpts().AppleKext && 213 MD->isVirtual() && 214 ME->hasQualifier()) 215 Callee = BuildAppleKextVirtualCall(MD, ME->getQualifier(), Ty); 216 else if (!DevirtualizedMethod) 217 Callee = CGM.GetAddrOfFunction(MD, Ty); 218 else { 219 Callee = CGM.GetAddrOfFunction(DevirtualizedMethod, Ty); 220 } 221 } 222 223 if (MD->isVirtual()) 224 This = CGM.getCXXABI().adjustThisArgumentForVirtualCall(*this, MD, This); 225 226 return EmitCXXMemberCall(MD, CE->getExprLoc(), Callee, ReturnValue, This, 227 /*ImplicitParam=*/0, QualType(), 228 CE->arg_begin(), CE->arg_end()); 229} 230 231RValue 232CodeGenFunction::EmitCXXMemberPointerCallExpr(const CXXMemberCallExpr *E, 233 ReturnValueSlot ReturnValue) { 234 const BinaryOperator *BO = 235 cast<BinaryOperator>(E->getCallee()->IgnoreParens()); 236 const Expr *BaseExpr = BO->getLHS(); 237 const Expr *MemFnExpr = BO->getRHS(); 238 239 const MemberPointerType *MPT = 240 MemFnExpr->getType()->castAs<MemberPointerType>(); 241 242 const FunctionProtoType *FPT = 243 MPT->getPointeeType()->castAs<FunctionProtoType>(); 244 const CXXRecordDecl *RD = 245 cast<CXXRecordDecl>(MPT->getClass()->getAs<RecordType>()->getDecl()); 246 247 // Get the member function pointer. 248 llvm::Value *MemFnPtr = EmitScalarExpr(MemFnExpr); 249 250 // Emit the 'this' pointer. 251 llvm::Value *This; 252 253 if (BO->getOpcode() == BO_PtrMemI) 254 This = EmitScalarExpr(BaseExpr); 255 else 256 This = EmitLValue(BaseExpr).getAddress(); 257 258 EmitTypeCheck(TCK_MemberCall, E->getExprLoc(), This, 259 QualType(MPT->getClass(), 0)); 260 261 // Ask the ABI to load the callee. Note that This is modified. 262 llvm::Value *Callee = 263 CGM.getCXXABI().EmitLoadOfMemberFunctionPointer(*this, This, MemFnPtr, MPT); 264 265 CallArgList Args; 266 267 QualType ThisType = 268 getContext().getPointerType(getContext().getTagDeclType(RD)); 269 270 // Push the this ptr. 271 Args.add(RValue::get(This), ThisType); 272 273 RequiredArgs required = RequiredArgs::forPrototypePlus(FPT, 1); 274 275 // And the rest of the call args 276 EmitCallArgs(Args, FPT, E->arg_begin(), E->arg_end()); 277 return EmitCall(CGM.getTypes().arrangeCXXMethodCall(Args, FPT, required), 278 Callee, ReturnValue, Args); 279} 280 281RValue 282CodeGenFunction::EmitCXXOperatorMemberCallExpr(const CXXOperatorCallExpr *E, 283 const CXXMethodDecl *MD, 284 ReturnValueSlot ReturnValue) { 285 assert(MD->isInstance() && 286 "Trying to emit a member call expr on a static method!"); 287 LValue LV = EmitLValue(E->getArg(0)); 288 llvm::Value *This = LV.getAddress(); 289 290 if ((MD->isCopyAssignmentOperator() || MD->isMoveAssignmentOperator()) && 291 MD->isTrivial()) { 292 llvm::Value *Src = EmitLValue(E->getArg(1)).getAddress(); 293 QualType Ty = E->getType(); 294 EmitAggregateAssign(This, Src, Ty); 295 return RValue::get(This); 296 } 297 298 llvm::Value *Callee = EmitCXXOperatorMemberCallee(E, MD, This); 299 return EmitCXXMemberCall(MD, E->getExprLoc(), Callee, ReturnValue, This, 300 /*ImplicitParam=*/0, QualType(), 301 E->arg_begin() + 1, E->arg_end()); 302} 303 304RValue CodeGenFunction::EmitCUDAKernelCallExpr(const CUDAKernelCallExpr *E, 305 ReturnValueSlot ReturnValue) { 306 return CGM.getCUDARuntime().EmitCUDAKernelCallExpr(*this, E, ReturnValue); 307} 308 309static void EmitNullBaseClassInitialization(CodeGenFunction &CGF, 310 llvm::Value *DestPtr, 311 const CXXRecordDecl *Base) { 312 if (Base->isEmpty()) 313 return; 314 315 DestPtr = CGF.EmitCastToVoidPtr(DestPtr); 316 317 const ASTRecordLayout &Layout = CGF.getContext().getASTRecordLayout(Base); 318 CharUnits Size = Layout.getNonVirtualSize(); 319 CharUnits Align = Layout.getNonVirtualAlign(); 320 321 llvm::Value *SizeVal = CGF.CGM.getSize(Size); 322 323 // If the type contains a pointer to data member we can't memset it to zero. 324 // Instead, create a null constant and copy it to the destination. 325 // TODO: there are other patterns besides zero that we can usefully memset, 326 // like -1, which happens to be the pattern used by member-pointers. 327 // TODO: isZeroInitializable can be over-conservative in the case where a 328 // virtual base contains a member pointer. 329 if (!CGF.CGM.getTypes().isZeroInitializable(Base)) { 330 llvm::Constant *NullConstant = CGF.CGM.EmitNullConstantForBase(Base); 331 332 llvm::GlobalVariable *NullVariable = 333 new llvm::GlobalVariable(CGF.CGM.getModule(), NullConstant->getType(), 334 /*isConstant=*/true, 335 llvm::GlobalVariable::PrivateLinkage, 336 NullConstant, Twine()); 337 NullVariable->setAlignment(Align.getQuantity()); 338 llvm::Value *SrcPtr = CGF.EmitCastToVoidPtr(NullVariable); 339 340 // Get and call the appropriate llvm.memcpy overload. 341 CGF.Builder.CreateMemCpy(DestPtr, SrcPtr, SizeVal, Align.getQuantity()); 342 return; 343 } 344 345 // Otherwise, just memset the whole thing to zero. This is legal 346 // because in LLVM, all default initializers (other than the ones we just 347 // handled above) are guaranteed to have a bit pattern of all zeros. 348 CGF.Builder.CreateMemSet(DestPtr, CGF.Builder.getInt8(0), SizeVal, 349 Align.getQuantity()); 350} 351 352void 353CodeGenFunction::EmitCXXConstructExpr(const CXXConstructExpr *E, 354 AggValueSlot Dest) { 355 assert(!Dest.isIgnored() && "Must have a destination!"); 356 const CXXConstructorDecl *CD = E->getConstructor(); 357 358 // If we require zero initialization before (or instead of) calling the 359 // constructor, as can be the case with a non-user-provided default 360 // constructor, emit the zero initialization now, unless destination is 361 // already zeroed. 362 if (E->requiresZeroInitialization() && !Dest.isZeroed()) { 363 switch (E->getConstructionKind()) { 364 case CXXConstructExpr::CK_Delegating: 365 case CXXConstructExpr::CK_Complete: 366 EmitNullInitialization(Dest.getAddr(), E->getType()); 367 break; 368 case CXXConstructExpr::CK_VirtualBase: 369 case CXXConstructExpr::CK_NonVirtualBase: 370 EmitNullBaseClassInitialization(*this, Dest.getAddr(), CD->getParent()); 371 break; 372 } 373 } 374 375 // If this is a call to a trivial default constructor, do nothing. 376 if (CD->isTrivial() && CD->isDefaultConstructor()) 377 return; 378 379 // Elide the constructor if we're constructing from a temporary. 380 // The temporary check is required because Sema sets this on NRVO 381 // returns. 382 if (getLangOpts().ElideConstructors && E->isElidable()) { 383 assert(getContext().hasSameUnqualifiedType(E->getType(), 384 E->getArg(0)->getType())); 385 if (E->getArg(0)->isTemporaryObject(getContext(), CD->getParent())) { 386 EmitAggExpr(E->getArg(0), Dest); 387 return; 388 } 389 } 390 391 if (const ConstantArrayType *arrayType 392 = getContext().getAsConstantArrayType(E->getType())) { 393 EmitCXXAggrConstructorCall(CD, arrayType, Dest.getAddr(), 394 E->arg_begin(), E->arg_end()); 395 } else { 396 CXXCtorType Type = Ctor_Complete; 397 bool ForVirtualBase = false; 398 bool Delegating = false; 399 400 switch (E->getConstructionKind()) { 401 case CXXConstructExpr::CK_Delegating: 402 // We should be emitting a constructor; GlobalDecl will assert this 403 Type = CurGD.getCtorType(); 404 Delegating = true; 405 break; 406 407 case CXXConstructExpr::CK_Complete: 408 Type = Ctor_Complete; 409 break; 410 411 case CXXConstructExpr::CK_VirtualBase: 412 ForVirtualBase = true; 413 // fall-through 414 415 case CXXConstructExpr::CK_NonVirtualBase: 416 Type = Ctor_Base; 417 } 418 419 // Call the constructor. 420 EmitCXXConstructorCall(CD, Type, ForVirtualBase, Delegating, Dest.getAddr(), 421 E->arg_begin(), E->arg_end()); 422 } 423} 424 425void 426CodeGenFunction::EmitSynthesizedCXXCopyCtor(llvm::Value *Dest, 427 llvm::Value *Src, 428 const Expr *Exp) { 429 if (const ExprWithCleanups *E = dyn_cast<ExprWithCleanups>(Exp)) 430 Exp = E->getSubExpr(); 431 assert(isa<CXXConstructExpr>(Exp) && 432 "EmitSynthesizedCXXCopyCtor - unknown copy ctor expr"); 433 const CXXConstructExpr* E = cast<CXXConstructExpr>(Exp); 434 const CXXConstructorDecl *CD = E->getConstructor(); 435 RunCleanupsScope Scope(*this); 436 437 // If we require zero initialization before (or instead of) calling the 438 // constructor, as can be the case with a non-user-provided default 439 // constructor, emit the zero initialization now. 440 // FIXME. Do I still need this for a copy ctor synthesis? 441 if (E->requiresZeroInitialization()) 442 EmitNullInitialization(Dest, E->getType()); 443 444 assert(!getContext().getAsConstantArrayType(E->getType()) 445 && "EmitSynthesizedCXXCopyCtor - Copied-in Array"); 446 EmitSynthesizedCXXCopyCtorCall(CD, Dest, Src, E->arg_begin(), E->arg_end()); 447} 448 449static CharUnits CalculateCookiePadding(CodeGenFunction &CGF, 450 const CXXNewExpr *E) { 451 if (!E->isArray()) 452 return CharUnits::Zero(); 453 454 // No cookie is required if the operator new[] being used is the 455 // reserved placement operator new[]. 456 if (E->getOperatorNew()->isReservedGlobalPlacementOperator()) 457 return CharUnits::Zero(); 458 459 return CGF.CGM.getCXXABI().GetArrayCookieSize(E); 460} 461 462static llvm::Value *EmitCXXNewAllocSize(CodeGenFunction &CGF, 463 const CXXNewExpr *e, 464 unsigned minElements, 465 llvm::Value *&numElements, 466 llvm::Value *&sizeWithoutCookie) { 467 QualType type = e->getAllocatedType(); 468 469 if (!e->isArray()) { 470 CharUnits typeSize = CGF.getContext().getTypeSizeInChars(type); 471 sizeWithoutCookie 472 = llvm::ConstantInt::get(CGF.SizeTy, typeSize.getQuantity()); 473 return sizeWithoutCookie; 474 } 475 476 // The width of size_t. 477 unsigned sizeWidth = CGF.SizeTy->getBitWidth(); 478 479 // Figure out the cookie size. 480 llvm::APInt cookieSize(sizeWidth, 481 CalculateCookiePadding(CGF, e).getQuantity()); 482 483 // Emit the array size expression. 484 // We multiply the size of all dimensions for NumElements. 485 // e.g for 'int[2][3]', ElemType is 'int' and NumElements is 6. 486 numElements = CGF.EmitScalarExpr(e->getArraySize()); 487 assert(isa<llvm::IntegerType>(numElements->getType())); 488 489 // The number of elements can be have an arbitrary integer type; 490 // essentially, we need to multiply it by a constant factor, add a 491 // cookie size, and verify that the result is representable as a 492 // size_t. That's just a gloss, though, and it's wrong in one 493 // important way: if the count is negative, it's an error even if 494 // the cookie size would bring the total size >= 0. 495 bool isSigned 496 = e->getArraySize()->getType()->isSignedIntegerOrEnumerationType(); 497 llvm::IntegerType *numElementsType 498 = cast<llvm::IntegerType>(numElements->getType()); 499 unsigned numElementsWidth = numElementsType->getBitWidth(); 500 501 // Compute the constant factor. 502 llvm::APInt arraySizeMultiplier(sizeWidth, 1); 503 while (const ConstantArrayType *CAT 504 = CGF.getContext().getAsConstantArrayType(type)) { 505 type = CAT->getElementType(); 506 arraySizeMultiplier *= CAT->getSize(); 507 } 508 509 CharUnits typeSize = CGF.getContext().getTypeSizeInChars(type); 510 llvm::APInt typeSizeMultiplier(sizeWidth, typeSize.getQuantity()); 511 typeSizeMultiplier *= arraySizeMultiplier; 512 513 // This will be a size_t. 514 llvm::Value *size; 515 516 // If someone is doing 'new int[42]' there is no need to do a dynamic check. 517 // Don't bloat the -O0 code. 518 if (llvm::ConstantInt *numElementsC = 519 dyn_cast<llvm::ConstantInt>(numElements)) { 520 const llvm::APInt &count = numElementsC->getValue(); 521 522 bool hasAnyOverflow = false; 523 524 // If 'count' was a negative number, it's an overflow. 525 if (isSigned && count.isNegative()) 526 hasAnyOverflow = true; 527 528 // We want to do all this arithmetic in size_t. If numElements is 529 // wider than that, check whether it's already too big, and if so, 530 // overflow. 531 else if (numElementsWidth > sizeWidth && 532 numElementsWidth - sizeWidth > count.countLeadingZeros()) 533 hasAnyOverflow = true; 534 535 // Okay, compute a count at the right width. 536 llvm::APInt adjustedCount = count.zextOrTrunc(sizeWidth); 537 538 // If there is a brace-initializer, we cannot allocate fewer elements than 539 // there are initializers. If we do, that's treated like an overflow. 540 if (adjustedCount.ult(minElements)) 541 hasAnyOverflow = true; 542 543 // Scale numElements by that. This might overflow, but we don't 544 // care because it only overflows if allocationSize does, too, and 545 // if that overflows then we shouldn't use this. 546 numElements = llvm::ConstantInt::get(CGF.SizeTy, 547 adjustedCount * arraySizeMultiplier); 548 549 // Compute the size before cookie, and track whether it overflowed. 550 bool overflow; 551 llvm::APInt allocationSize 552 = adjustedCount.umul_ov(typeSizeMultiplier, overflow); 553 hasAnyOverflow |= overflow; 554 555 // Add in the cookie, and check whether it's overflowed. 556 if (cookieSize != 0) { 557 // Save the current size without a cookie. This shouldn't be 558 // used if there was overflow. 559 sizeWithoutCookie = llvm::ConstantInt::get(CGF.SizeTy, allocationSize); 560 561 allocationSize = allocationSize.uadd_ov(cookieSize, overflow); 562 hasAnyOverflow |= overflow; 563 } 564 565 // On overflow, produce a -1 so operator new will fail. 566 if (hasAnyOverflow) { 567 size = llvm::Constant::getAllOnesValue(CGF.SizeTy); 568 } else { 569 size = llvm::ConstantInt::get(CGF.SizeTy, allocationSize); 570 } 571 572 // Otherwise, we might need to use the overflow intrinsics. 573 } else { 574 // There are up to five conditions we need to test for: 575 // 1) if isSigned, we need to check whether numElements is negative; 576 // 2) if numElementsWidth > sizeWidth, we need to check whether 577 // numElements is larger than something representable in size_t; 578 // 3) if minElements > 0, we need to check whether numElements is smaller 579 // than that. 580 // 4) we need to compute 581 // sizeWithoutCookie := numElements * typeSizeMultiplier 582 // and check whether it overflows; and 583 // 5) if we need a cookie, we need to compute 584 // size := sizeWithoutCookie + cookieSize 585 // and check whether it overflows. 586 587 llvm::Value *hasOverflow = 0; 588 589 // If numElementsWidth > sizeWidth, then one way or another, we're 590 // going to have to do a comparison for (2), and this happens to 591 // take care of (1), too. 592 if (numElementsWidth > sizeWidth) { 593 llvm::APInt threshold(numElementsWidth, 1); 594 threshold <<= sizeWidth; 595 596 llvm::Value *thresholdV 597 = llvm::ConstantInt::get(numElementsType, threshold); 598 599 hasOverflow = CGF.Builder.CreateICmpUGE(numElements, thresholdV); 600 numElements = CGF.Builder.CreateTrunc(numElements, CGF.SizeTy); 601 602 // Otherwise, if we're signed, we want to sext up to size_t. 603 } else if (isSigned) { 604 if (numElementsWidth < sizeWidth) 605 numElements = CGF.Builder.CreateSExt(numElements, CGF.SizeTy); 606 607 // If there's a non-1 type size multiplier, then we can do the 608 // signedness check at the same time as we do the multiply 609 // because a negative number times anything will cause an 610 // unsigned overflow. Otherwise, we have to do it here. But at least 611 // in this case, we can subsume the >= minElements check. 612 if (typeSizeMultiplier == 1) 613 hasOverflow = CGF.Builder.CreateICmpSLT(numElements, 614 llvm::ConstantInt::get(CGF.SizeTy, minElements)); 615 616 // Otherwise, zext up to size_t if necessary. 617 } else if (numElementsWidth < sizeWidth) { 618 numElements = CGF.Builder.CreateZExt(numElements, CGF.SizeTy); 619 } 620 621 assert(numElements->getType() == CGF.SizeTy); 622 623 if (minElements) { 624 // Don't allow allocation of fewer elements than we have initializers. 625 if (!hasOverflow) { 626 hasOverflow = CGF.Builder.CreateICmpULT(numElements, 627 llvm::ConstantInt::get(CGF.SizeTy, minElements)); 628 } else if (numElementsWidth > sizeWidth) { 629 // The other existing overflow subsumes this check. 630 // We do an unsigned comparison, since any signed value < -1 is 631 // taken care of either above or below. 632 hasOverflow = CGF.Builder.CreateOr(hasOverflow, 633 CGF.Builder.CreateICmpULT(numElements, 634 llvm::ConstantInt::get(CGF.SizeTy, minElements))); 635 } 636 } 637 638 size = numElements; 639 640 // Multiply by the type size if necessary. This multiplier 641 // includes all the factors for nested arrays. 642 // 643 // This step also causes numElements to be scaled up by the 644 // nested-array factor if necessary. Overflow on this computation 645 // can be ignored because the result shouldn't be used if 646 // allocation fails. 647 if (typeSizeMultiplier != 1) { 648 llvm::Value *umul_with_overflow 649 = CGF.CGM.getIntrinsic(llvm::Intrinsic::umul_with_overflow, CGF.SizeTy); 650 651 llvm::Value *tsmV = 652 llvm::ConstantInt::get(CGF.SizeTy, typeSizeMultiplier); 653 llvm::Value *result = 654 CGF.Builder.CreateCall2(umul_with_overflow, size, tsmV); 655 656 llvm::Value *overflowed = CGF.Builder.CreateExtractValue(result, 1); 657 if (hasOverflow) 658 hasOverflow = CGF.Builder.CreateOr(hasOverflow, overflowed); 659 else 660 hasOverflow = overflowed; 661 662 size = CGF.Builder.CreateExtractValue(result, 0); 663 664 // Also scale up numElements by the array size multiplier. 665 if (arraySizeMultiplier != 1) { 666 // If the base element type size is 1, then we can re-use the 667 // multiply we just did. 668 if (typeSize.isOne()) { 669 assert(arraySizeMultiplier == typeSizeMultiplier); 670 numElements = size; 671 672 // Otherwise we need a separate multiply. 673 } else { 674 llvm::Value *asmV = 675 llvm::ConstantInt::get(CGF.SizeTy, arraySizeMultiplier); 676 numElements = CGF.Builder.CreateMul(numElements, asmV); 677 } 678 } 679 } else { 680 // numElements doesn't need to be scaled. 681 assert(arraySizeMultiplier == 1); 682 } 683 684 // Add in the cookie size if necessary. 685 if (cookieSize != 0) { 686 sizeWithoutCookie = size; 687 688 llvm::Value *uadd_with_overflow 689 = CGF.CGM.getIntrinsic(llvm::Intrinsic::uadd_with_overflow, CGF.SizeTy); 690 691 llvm::Value *cookieSizeV = llvm::ConstantInt::get(CGF.SizeTy, cookieSize); 692 llvm::Value *result = 693 CGF.Builder.CreateCall2(uadd_with_overflow, size, cookieSizeV); 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 } 703 704 // If we had any possibility of dynamic overflow, make a select to 705 // overwrite 'size' with an all-ones value, which should cause 706 // operator new to throw. 707 if (hasOverflow) 708 size = CGF.Builder.CreateSelect(hasOverflow, 709 llvm::Constant::getAllOnesValue(CGF.SizeTy), 710 size); 711 } 712 713 if (cookieSize == 0) 714 sizeWithoutCookie = size; 715 else 716 assert(sizeWithoutCookie && "didn't set sizeWithoutCookie?"); 717 718 return size; 719} 720 721static void StoreAnyExprIntoOneUnit(CodeGenFunction &CGF, const Expr *Init, 722 QualType AllocType, llvm::Value *NewPtr) { 723 // FIXME: Refactor with EmitExprAsInit. 724 CharUnits Alignment = CGF.getContext().getTypeAlignInChars(AllocType); 725 switch (CGF.getEvaluationKind(AllocType)) { 726 case TEK_Scalar: 727 CGF.EmitScalarInit(Init, 0, CGF.MakeAddrLValue(NewPtr, AllocType, 728 Alignment), 729 false); 730 return; 731 case TEK_Complex: 732 CGF.EmitComplexExprIntoLValue(Init, CGF.MakeAddrLValue(NewPtr, AllocType, 733 Alignment), 734 /*isInit*/ true); 735 return; 736 case TEK_Aggregate: { 737 AggValueSlot Slot 738 = AggValueSlot::forAddr(NewPtr, Alignment, AllocType.getQualifiers(), 739 AggValueSlot::IsDestructed, 740 AggValueSlot::DoesNotNeedGCBarriers, 741 AggValueSlot::IsNotAliased); 742 CGF.EmitAggExpr(Init, Slot); 743 return; 744 } 745 } 746 llvm_unreachable("bad evaluation kind"); 747} 748 749void 750CodeGenFunction::EmitNewArrayInitializer(const CXXNewExpr *E, 751 QualType elementType, 752 llvm::Value *beginPtr, 753 llvm::Value *numElements) { 754 if (!E->hasInitializer()) 755 return; // We have a POD type. 756 757 llvm::Value *explicitPtr = beginPtr; 758 // Find the end of the array, hoisted out of the loop. 759 llvm::Value *endPtr = 760 Builder.CreateInBoundsGEP(beginPtr, numElements, "array.end"); 761 762 unsigned initializerElements = 0; 763 764 const Expr *Init = E->getInitializer(); 765 llvm::AllocaInst *endOfInit = 0; 766 QualType::DestructionKind dtorKind = elementType.isDestructedType(); 767 EHScopeStack::stable_iterator cleanup; 768 llvm::Instruction *cleanupDominator = 0; 769 770 // If the initializer is an initializer list, first do the explicit elements. 771 if (const InitListExpr *ILE = dyn_cast<InitListExpr>(Init)) { 772 initializerElements = ILE->getNumInits(); 773 774 // If this is a multi-dimensional array new, we will initialize multiple 775 // elements with each init list element. 776 QualType AllocType = E->getAllocatedType(); 777 if (const ConstantArrayType *CAT = dyn_cast_or_null<ConstantArrayType>( 778 AllocType->getAsArrayTypeUnsafe())) { 779 unsigned AS = explicitPtr->getType()->getPointerAddressSpace(); 780 llvm::Type *AllocPtrTy = ConvertTypeForMem(AllocType)->getPointerTo(AS); 781 explicitPtr = Builder.CreateBitCast(explicitPtr, AllocPtrTy); 782 initializerElements *= getContext().getConstantArrayElementCount(CAT); 783 } 784 785 // Enter a partial-destruction cleanup if necessary. 786 if (needsEHCleanup(dtorKind)) { 787 // In principle we could tell the cleanup where we are more 788 // directly, but the control flow can get so varied here that it 789 // would actually be quite complex. Therefore we go through an 790 // alloca. 791 endOfInit = CreateTempAlloca(beginPtr->getType(), "array.endOfInit"); 792 cleanupDominator = Builder.CreateStore(beginPtr, endOfInit); 793 pushIrregularPartialArrayCleanup(beginPtr, endOfInit, elementType, 794 getDestroyer(dtorKind)); 795 cleanup = EHStack.stable_begin(); 796 } 797 798 for (unsigned i = 0, e = ILE->getNumInits(); i != e; ++i) { 799 // Tell the cleanup that it needs to destroy up to this 800 // element. TODO: some of these stores can be trivially 801 // observed to be unnecessary. 802 if (endOfInit) Builder.CreateStore(explicitPtr, endOfInit); 803 StoreAnyExprIntoOneUnit(*this, ILE->getInit(i), 804 ILE->getInit(i)->getType(), explicitPtr); 805 explicitPtr = Builder.CreateConstGEP1_32(explicitPtr, 1, 806 "array.exp.next"); 807 } 808 809 // The remaining elements are filled with the array filler expression. 810 Init = ILE->getArrayFiller(); 811 812 explicitPtr = Builder.CreateBitCast(explicitPtr, beginPtr->getType()); 813 } 814 815 // Create the continuation block. 816 llvm::BasicBlock *contBB = createBasicBlock("new.loop.end"); 817 818 // If the number of elements isn't constant, we have to now check if there is 819 // anything left to initialize. 820 if (llvm::ConstantInt *constNum = dyn_cast<llvm::ConstantInt>(numElements)) { 821 // If all elements have already been initialized, skip the whole loop. 822 if (constNum->getZExtValue() <= initializerElements) { 823 // If there was a cleanup, deactivate it. 824 if (cleanupDominator) 825 DeactivateCleanupBlock(cleanup, cleanupDominator); 826 return; 827 } 828 } else { 829 llvm::BasicBlock *nonEmptyBB = createBasicBlock("new.loop.nonempty"); 830 llvm::Value *isEmpty = Builder.CreateICmpEQ(explicitPtr, endPtr, 831 "array.isempty"); 832 Builder.CreateCondBr(isEmpty, contBB, nonEmptyBB); 833 EmitBlock(nonEmptyBB); 834 } 835 836 // Enter the loop. 837 llvm::BasicBlock *entryBB = Builder.GetInsertBlock(); 838 llvm::BasicBlock *loopBB = createBasicBlock("new.loop"); 839 840 EmitBlock(loopBB); 841 842 // Set up the current-element phi. 843 llvm::PHINode *curPtr = 844 Builder.CreatePHI(explicitPtr->getType(), 2, "array.cur"); 845 curPtr->addIncoming(explicitPtr, entryBB); 846 847 // Store the new cleanup position for irregular cleanups. 848 if (endOfInit) Builder.CreateStore(curPtr, endOfInit); 849 850 // Enter a partial-destruction cleanup if necessary. 851 if (!cleanupDominator && needsEHCleanup(dtorKind)) { 852 pushRegularPartialArrayCleanup(beginPtr, curPtr, elementType, 853 getDestroyer(dtorKind)); 854 cleanup = EHStack.stable_begin(); 855 cleanupDominator = Builder.CreateUnreachable(); 856 } 857 858 // Emit the initializer into this element. 859 StoreAnyExprIntoOneUnit(*this, Init, E->getAllocatedType(), curPtr); 860 861 // Leave the cleanup if we entered one. 862 if (cleanupDominator) { 863 DeactivateCleanupBlock(cleanup, cleanupDominator); 864 cleanupDominator->eraseFromParent(); 865 } 866 867 // Advance to the next element. 868 llvm::Value *nextPtr = Builder.CreateConstGEP1_32(curPtr, 1, "array.next"); 869 870 // Check whether we've gotten to the end of the array and, if so, 871 // exit the loop. 872 llvm::Value *isEnd = Builder.CreateICmpEQ(nextPtr, endPtr, "array.atend"); 873 Builder.CreateCondBr(isEnd, contBB, loopBB); 874 curPtr->addIncoming(nextPtr, Builder.GetInsertBlock()); 875 876 EmitBlock(contBB); 877} 878 879static void EmitZeroMemSet(CodeGenFunction &CGF, QualType T, 880 llvm::Value *NewPtr, llvm::Value *Size) { 881 CGF.EmitCastToVoidPtr(NewPtr); 882 CharUnits Alignment = CGF.getContext().getTypeAlignInChars(T); 883 CGF.Builder.CreateMemSet(NewPtr, CGF.Builder.getInt8(0), Size, 884 Alignment.getQuantity(), false); 885} 886 887static void EmitNewInitializer(CodeGenFunction &CGF, const CXXNewExpr *E, 888 QualType ElementType, 889 llvm::Value *NewPtr, 890 llvm::Value *NumElements, 891 llvm::Value *AllocSizeWithoutCookie) { 892 const Expr *Init = E->getInitializer(); 893 if (E->isArray()) { 894 if (const CXXConstructExpr *CCE = dyn_cast_or_null<CXXConstructExpr>(Init)){ 895 CXXConstructorDecl *Ctor = CCE->getConstructor(); 896 if (Ctor->isTrivial()) { 897 // If new expression did not specify value-initialization, then there 898 // is no initialization. 899 if (!CCE->requiresZeroInitialization() || Ctor->getParent()->isEmpty()) 900 return; 901 902 if (CGF.CGM.getTypes().isZeroInitializable(ElementType)) { 903 // Optimization: since zero initialization will just set the memory 904 // to all zeroes, generate a single memset to do it in one shot. 905 EmitZeroMemSet(CGF, ElementType, NewPtr, AllocSizeWithoutCookie); 906 return; 907 } 908 } 909 910 CGF.EmitCXXAggrConstructorCall(Ctor, NumElements, NewPtr, 911 CCE->arg_begin(), CCE->arg_end(), 912 CCE->requiresZeroInitialization()); 913 return; 914 } else if (Init && isa<ImplicitValueInitExpr>(Init) && 915 CGF.CGM.getTypes().isZeroInitializable(ElementType)) { 916 // Optimization: since zero initialization will just set the memory 917 // to all zeroes, generate a single memset to do it in one shot. 918 EmitZeroMemSet(CGF, ElementType, NewPtr, AllocSizeWithoutCookie); 919 return; 920 } 921 CGF.EmitNewArrayInitializer(E, ElementType, NewPtr, NumElements); 922 return; 923 } 924 925 if (!Init) 926 return; 927 928 StoreAnyExprIntoOneUnit(CGF, Init, E->getAllocatedType(), NewPtr); 929} 930 931/// Emit a call to an operator new or operator delete function, as implicitly 932/// created by new-expressions and delete-expressions. 933static RValue EmitNewDeleteCall(CodeGenFunction &CGF, 934 const FunctionDecl *Callee, 935 const FunctionProtoType *CalleeType, 936 const CallArgList &Args) { 937 llvm::Instruction *CallOrInvoke; 938 llvm::Value *CalleeAddr = CGF.CGM.GetAddrOfFunction(Callee); 939 RValue RV = 940 CGF.EmitCall(CGF.CGM.getTypes().arrangeFreeFunctionCall(Args, CalleeType), 941 CalleeAddr, ReturnValueSlot(), Args, 942 Callee, &CallOrInvoke); 943 944 /// C++1y [expr.new]p10: 945 /// [In a new-expression,] an implementation is allowed to omit a call 946 /// to a replaceable global allocation function. 947 /// 948 /// We model such elidable calls with the 'builtin' attribute. 949 llvm::Function *Fn = dyn_cast<llvm::Function>(CalleeAddr); 950 if (Callee->isReplaceableGlobalAllocationFunction() && 951 Fn && Fn->hasFnAttribute(llvm::Attribute::NoBuiltin)) { 952 // FIXME: Add addAttribute to CallSite. 953 if (llvm::CallInst *CI = dyn_cast<llvm::CallInst>(CallOrInvoke)) 954 CI->addAttribute(llvm::AttributeSet::FunctionIndex, 955 llvm::Attribute::Builtin); 956 else if (llvm::InvokeInst *II = dyn_cast<llvm::InvokeInst>(CallOrInvoke)) 957 II->addAttribute(llvm::AttributeSet::FunctionIndex, 958 llvm::Attribute::Builtin); 959 else 960 llvm_unreachable("unexpected kind of call instruction"); 961 } 962 963 return RV; 964} 965 966namespace { 967 /// A cleanup to call the given 'operator delete' function upon 968 /// abnormal exit from a new expression. 969 class CallDeleteDuringNew : public EHScopeStack::Cleanup { 970 size_t NumPlacementArgs; 971 const FunctionDecl *OperatorDelete; 972 llvm::Value *Ptr; 973 llvm::Value *AllocSize; 974 975 RValue *getPlacementArgs() { return reinterpret_cast<RValue*>(this+1); } 976 977 public: 978 static size_t getExtraSize(size_t NumPlacementArgs) { 979 return NumPlacementArgs * sizeof(RValue); 980 } 981 982 CallDeleteDuringNew(size_t NumPlacementArgs, 983 const FunctionDecl *OperatorDelete, 984 llvm::Value *Ptr, 985 llvm::Value *AllocSize) 986 : NumPlacementArgs(NumPlacementArgs), OperatorDelete(OperatorDelete), 987 Ptr(Ptr), AllocSize(AllocSize) {} 988 989 void setPlacementArg(unsigned I, RValue Arg) { 990 assert(I < NumPlacementArgs && "index out of range"); 991 getPlacementArgs()[I] = Arg; 992 } 993 994 void Emit(CodeGenFunction &CGF, Flags flags) { 995 const FunctionProtoType *FPT 996 = OperatorDelete->getType()->getAs<FunctionProtoType>(); 997 assert(FPT->getNumArgs() == NumPlacementArgs + 1 || 998 (FPT->getNumArgs() == 2 && NumPlacementArgs == 0)); 999 1000 CallArgList DeleteArgs; 1001 1002 // The first argument is always a void*. 1003 FunctionProtoType::arg_type_iterator AI = FPT->arg_type_begin(); 1004 DeleteArgs.add(RValue::get(Ptr), *AI++); 1005 1006 // A member 'operator delete' can take an extra 'size_t' argument. 1007 if (FPT->getNumArgs() == NumPlacementArgs + 2) 1008 DeleteArgs.add(RValue::get(AllocSize), *AI++); 1009 1010 // Pass the rest of the arguments, which must match exactly. 1011 for (unsigned I = 0; I != NumPlacementArgs; ++I) 1012 DeleteArgs.add(getPlacementArgs()[I], *AI++); 1013 1014 // Call 'operator delete'. 1015 EmitNewDeleteCall(CGF, OperatorDelete, FPT, DeleteArgs); 1016 } 1017 }; 1018 1019 /// A cleanup to call the given 'operator delete' function upon 1020 /// abnormal exit from a new expression when the new expression is 1021 /// conditional. 1022 class CallDeleteDuringConditionalNew : public EHScopeStack::Cleanup { 1023 size_t NumPlacementArgs; 1024 const FunctionDecl *OperatorDelete; 1025 DominatingValue<RValue>::saved_type Ptr; 1026 DominatingValue<RValue>::saved_type AllocSize; 1027 1028 DominatingValue<RValue>::saved_type *getPlacementArgs() { 1029 return reinterpret_cast<DominatingValue<RValue>::saved_type*>(this+1); 1030 } 1031 1032 public: 1033 static size_t getExtraSize(size_t NumPlacementArgs) { 1034 return NumPlacementArgs * sizeof(DominatingValue<RValue>::saved_type); 1035 } 1036 1037 CallDeleteDuringConditionalNew(size_t NumPlacementArgs, 1038 const FunctionDecl *OperatorDelete, 1039 DominatingValue<RValue>::saved_type Ptr, 1040 DominatingValue<RValue>::saved_type AllocSize) 1041 : NumPlacementArgs(NumPlacementArgs), OperatorDelete(OperatorDelete), 1042 Ptr(Ptr), AllocSize(AllocSize) {} 1043 1044 void setPlacementArg(unsigned I, DominatingValue<RValue>::saved_type Arg) { 1045 assert(I < NumPlacementArgs && "index out of range"); 1046 getPlacementArgs()[I] = Arg; 1047 } 1048 1049 void Emit(CodeGenFunction &CGF, Flags flags) { 1050 const FunctionProtoType *FPT 1051 = OperatorDelete->getType()->getAs<FunctionProtoType>(); 1052 assert(FPT->getNumArgs() == NumPlacementArgs + 1 || 1053 (FPT->getNumArgs() == 2 && NumPlacementArgs == 0)); 1054 1055 CallArgList DeleteArgs; 1056 1057 // The first argument is always a void*. 1058 FunctionProtoType::arg_type_iterator AI = FPT->arg_type_begin(); 1059 DeleteArgs.add(Ptr.restore(CGF), *AI++); 1060 1061 // A member 'operator delete' can take an extra 'size_t' argument. 1062 if (FPT->getNumArgs() == NumPlacementArgs + 2) { 1063 RValue RV = AllocSize.restore(CGF); 1064 DeleteArgs.add(RV, *AI++); 1065 } 1066 1067 // Pass the rest of the arguments, which must match exactly. 1068 for (unsigned I = 0; I != NumPlacementArgs; ++I) { 1069 RValue RV = getPlacementArgs()[I].restore(CGF); 1070 DeleteArgs.add(RV, *AI++); 1071 } 1072 1073 // Call 'operator delete'. 1074 EmitNewDeleteCall(CGF, OperatorDelete, FPT, DeleteArgs); 1075 } 1076 }; 1077} 1078 1079/// Enter a cleanup to call 'operator delete' if the initializer in a 1080/// new-expression throws. 1081static void EnterNewDeleteCleanup(CodeGenFunction &CGF, 1082 const CXXNewExpr *E, 1083 llvm::Value *NewPtr, 1084 llvm::Value *AllocSize, 1085 const CallArgList &NewArgs) { 1086 // If we're not inside a conditional branch, then the cleanup will 1087 // dominate and we can do the easier (and more efficient) thing. 1088 if (!CGF.isInConditionalBranch()) { 1089 CallDeleteDuringNew *Cleanup = CGF.EHStack 1090 .pushCleanupWithExtra<CallDeleteDuringNew>(EHCleanup, 1091 E->getNumPlacementArgs(), 1092 E->getOperatorDelete(), 1093 NewPtr, AllocSize); 1094 for (unsigned I = 0, N = E->getNumPlacementArgs(); I != N; ++I) 1095 Cleanup->setPlacementArg(I, NewArgs[I+1].RV); 1096 1097 return; 1098 } 1099 1100 // Otherwise, we need to save all this stuff. 1101 DominatingValue<RValue>::saved_type SavedNewPtr = 1102 DominatingValue<RValue>::save(CGF, RValue::get(NewPtr)); 1103 DominatingValue<RValue>::saved_type SavedAllocSize = 1104 DominatingValue<RValue>::save(CGF, RValue::get(AllocSize)); 1105 1106 CallDeleteDuringConditionalNew *Cleanup = CGF.EHStack 1107 .pushCleanupWithExtra<CallDeleteDuringConditionalNew>(EHCleanup, 1108 E->getNumPlacementArgs(), 1109 E->getOperatorDelete(), 1110 SavedNewPtr, 1111 SavedAllocSize); 1112 for (unsigned I = 0, N = E->getNumPlacementArgs(); I != N; ++I) 1113 Cleanup->setPlacementArg(I, 1114 DominatingValue<RValue>::save(CGF, NewArgs[I+1].RV)); 1115 1116 CGF.initFullExprCleanup(); 1117} 1118 1119llvm::Value *CodeGenFunction::EmitCXXNewExpr(const CXXNewExpr *E) { 1120 // The element type being allocated. 1121 QualType allocType = getContext().getBaseElementType(E->getAllocatedType()); 1122 1123 // 1. Build a call to the allocation function. 1124 FunctionDecl *allocator = E->getOperatorNew(); 1125 const FunctionProtoType *allocatorType = 1126 allocator->getType()->castAs<FunctionProtoType>(); 1127 1128 CallArgList allocatorArgs; 1129 1130 // The allocation size is the first argument. 1131 QualType sizeType = getContext().getSizeType(); 1132 1133 // If there is a brace-initializer, cannot allocate fewer elements than inits. 1134 unsigned minElements = 0; 1135 if (E->isArray() && E->hasInitializer()) { 1136 if (const InitListExpr *ILE = dyn_cast<InitListExpr>(E->getInitializer())) 1137 minElements = ILE->getNumInits(); 1138 } 1139 1140 llvm::Value *numElements = 0; 1141 llvm::Value *allocSizeWithoutCookie = 0; 1142 llvm::Value *allocSize = 1143 EmitCXXNewAllocSize(*this, E, minElements, numElements, 1144 allocSizeWithoutCookie); 1145 1146 allocatorArgs.add(RValue::get(allocSize), sizeType); 1147 1148 // Emit the rest of the arguments. 1149 // FIXME: Ideally, this should just use EmitCallArgs. 1150 CXXNewExpr::const_arg_iterator placementArg = E->placement_arg_begin(); 1151 1152 // First, use the types from the function type. 1153 // We start at 1 here because the first argument (the allocation size) 1154 // has already been emitted. 1155 for (unsigned i = 1, e = allocatorType->getNumArgs(); i != e; 1156 ++i, ++placementArg) { 1157 QualType argType = allocatorType->getArgType(i); 1158 1159 assert(getContext().hasSameUnqualifiedType(argType.getNonReferenceType(), 1160 placementArg->getType()) && 1161 "type mismatch in call argument!"); 1162 1163 EmitCallArg(allocatorArgs, *placementArg, argType); 1164 } 1165 1166 // Either we've emitted all the call args, or we have a call to a 1167 // variadic function. 1168 assert((placementArg == E->placement_arg_end() || 1169 allocatorType->isVariadic()) && 1170 "Extra arguments to non-variadic function!"); 1171 1172 // If we still have any arguments, emit them using the type of the argument. 1173 for (CXXNewExpr::const_arg_iterator placementArgsEnd = E->placement_arg_end(); 1174 placementArg != placementArgsEnd; ++placementArg) { 1175 EmitCallArg(allocatorArgs, *placementArg, placementArg->getType()); 1176 } 1177 1178 // Emit the allocation call. If the allocator is a global placement 1179 // operator, just "inline" it directly. 1180 RValue RV; 1181 if (allocator->isReservedGlobalPlacementOperator()) { 1182 assert(allocatorArgs.size() == 2); 1183 RV = allocatorArgs[1].RV; 1184 // TODO: kill any unnecessary computations done for the size 1185 // argument. 1186 } else { 1187 RV = EmitNewDeleteCall(*this, allocator, allocatorType, allocatorArgs); 1188 } 1189 1190 // Emit a null check on the allocation result if the allocation 1191 // function is allowed to return null (because it has a non-throwing 1192 // exception spec; for this part, we inline 1193 // CXXNewExpr::shouldNullCheckAllocation()) and we have an 1194 // interesting initializer. 1195 bool nullCheck = allocatorType->isNothrow(getContext()) && 1196 (!allocType.isPODType(getContext()) || E->hasInitializer()); 1197 1198 llvm::BasicBlock *nullCheckBB = 0; 1199 llvm::BasicBlock *contBB = 0; 1200 1201 llvm::Value *allocation = RV.getScalarVal(); 1202 unsigned AS = allocation->getType()->getPointerAddressSpace(); 1203 1204 // The null-check means that the initializer is conditionally 1205 // evaluated. 1206 ConditionalEvaluation conditional(*this); 1207 1208 if (nullCheck) { 1209 conditional.begin(*this); 1210 1211 nullCheckBB = Builder.GetInsertBlock(); 1212 llvm::BasicBlock *notNullBB = createBasicBlock("new.notnull"); 1213 contBB = createBasicBlock("new.cont"); 1214 1215 llvm::Value *isNull = Builder.CreateIsNull(allocation, "new.isnull"); 1216 Builder.CreateCondBr(isNull, contBB, notNullBB); 1217 EmitBlock(notNullBB); 1218 } 1219 1220 // If there's an operator delete, enter a cleanup to call it if an 1221 // exception is thrown. 1222 EHScopeStack::stable_iterator operatorDeleteCleanup; 1223 llvm::Instruction *cleanupDominator = 0; 1224 if (E->getOperatorDelete() && 1225 !E->getOperatorDelete()->isReservedGlobalPlacementOperator()) { 1226 EnterNewDeleteCleanup(*this, E, allocation, allocSize, allocatorArgs); 1227 operatorDeleteCleanup = EHStack.stable_begin(); 1228 cleanupDominator = Builder.CreateUnreachable(); 1229 } 1230 1231 assert((allocSize == allocSizeWithoutCookie) == 1232 CalculateCookiePadding(*this, E).isZero()); 1233 if (allocSize != allocSizeWithoutCookie) { 1234 assert(E->isArray()); 1235 allocation = CGM.getCXXABI().InitializeArrayCookie(*this, allocation, 1236 numElements, 1237 E, allocType); 1238 } 1239 1240 llvm::Type *elementPtrTy 1241 = ConvertTypeForMem(allocType)->getPointerTo(AS); 1242 llvm::Value *result = Builder.CreateBitCast(allocation, elementPtrTy); 1243 1244 EmitNewInitializer(*this, E, allocType, result, numElements, 1245 allocSizeWithoutCookie); 1246 if (E->isArray()) { 1247 // NewPtr is a pointer to the base element type. If we're 1248 // allocating an array of arrays, we'll need to cast back to the 1249 // array pointer type. 1250 llvm::Type *resultType = ConvertTypeForMem(E->getType()); 1251 if (result->getType() != resultType) 1252 result = Builder.CreateBitCast(result, resultType); 1253 } 1254 1255 // Deactivate the 'operator delete' cleanup if we finished 1256 // initialization. 1257 if (operatorDeleteCleanup.isValid()) { 1258 DeactivateCleanupBlock(operatorDeleteCleanup, cleanupDominator); 1259 cleanupDominator->eraseFromParent(); 1260 } 1261 1262 if (nullCheck) { 1263 conditional.end(*this); 1264 1265 llvm::BasicBlock *notNullBB = Builder.GetInsertBlock(); 1266 EmitBlock(contBB); 1267 1268 llvm::PHINode *PHI = Builder.CreatePHI(result->getType(), 2); 1269 PHI->addIncoming(result, notNullBB); 1270 PHI->addIncoming(llvm::Constant::getNullValue(result->getType()), 1271 nullCheckBB); 1272 1273 result = PHI; 1274 } 1275 1276 return result; 1277} 1278 1279void CodeGenFunction::EmitDeleteCall(const FunctionDecl *DeleteFD, 1280 llvm::Value *Ptr, 1281 QualType DeleteTy) { 1282 assert(DeleteFD->getOverloadedOperator() == OO_Delete); 1283 1284 const FunctionProtoType *DeleteFTy = 1285 DeleteFD->getType()->getAs<FunctionProtoType>(); 1286 1287 CallArgList DeleteArgs; 1288 1289 // Check if we need to pass the size to the delete operator. 1290 llvm::Value *Size = 0; 1291 QualType SizeTy; 1292 if (DeleteFTy->getNumArgs() == 2) { 1293 SizeTy = DeleteFTy->getArgType(1); 1294 CharUnits DeleteTypeSize = getContext().getTypeSizeInChars(DeleteTy); 1295 Size = llvm::ConstantInt::get(ConvertType(SizeTy), 1296 DeleteTypeSize.getQuantity()); 1297 } 1298 1299 QualType ArgTy = DeleteFTy->getArgType(0); 1300 llvm::Value *DeletePtr = Builder.CreateBitCast(Ptr, ConvertType(ArgTy)); 1301 DeleteArgs.add(RValue::get(DeletePtr), ArgTy); 1302 1303 if (Size) 1304 DeleteArgs.add(RValue::get(Size), SizeTy); 1305 1306 // Emit the call to delete. 1307 EmitNewDeleteCall(*this, DeleteFD, DeleteFTy, DeleteArgs); 1308} 1309 1310namespace { 1311 /// Calls the given 'operator delete' on a single object. 1312 struct CallObjectDelete : EHScopeStack::Cleanup { 1313 llvm::Value *Ptr; 1314 const FunctionDecl *OperatorDelete; 1315 QualType ElementType; 1316 1317 CallObjectDelete(llvm::Value *Ptr, 1318 const FunctionDecl *OperatorDelete, 1319 QualType ElementType) 1320 : Ptr(Ptr), OperatorDelete(OperatorDelete), ElementType(ElementType) {} 1321 1322 void Emit(CodeGenFunction &CGF, Flags flags) { 1323 CGF.EmitDeleteCall(OperatorDelete, Ptr, ElementType); 1324 } 1325 }; 1326} 1327 1328/// Emit the code for deleting a single object. 1329static void EmitObjectDelete(CodeGenFunction &CGF, 1330 const FunctionDecl *OperatorDelete, 1331 llvm::Value *Ptr, 1332 QualType ElementType, 1333 bool UseGlobalDelete) { 1334 // Find the destructor for the type, if applicable. If the 1335 // destructor is virtual, we'll just emit the vcall and return. 1336 const CXXDestructorDecl *Dtor = 0; 1337 if (const RecordType *RT = ElementType->getAs<RecordType>()) { 1338 CXXRecordDecl *RD = cast<CXXRecordDecl>(RT->getDecl()); 1339 if (RD->hasDefinition() && !RD->hasTrivialDestructor()) { 1340 Dtor = RD->getDestructor(); 1341 1342 if (Dtor->isVirtual()) { 1343 if (UseGlobalDelete) { 1344 // If we're supposed to call the global delete, make sure we do so 1345 // even if the destructor throws. 1346 1347 // Derive the complete-object pointer, which is what we need 1348 // to pass to the deallocation function. 1349 llvm::Value *completePtr = 1350 CGF.CGM.getCXXABI().adjustToCompleteObject(CGF, Ptr, ElementType); 1351 1352 CGF.EHStack.pushCleanup<CallObjectDelete>(NormalAndEHCleanup, 1353 completePtr, OperatorDelete, 1354 ElementType); 1355 } 1356 1357 // FIXME: Provide a source location here. 1358 CXXDtorType DtorType = UseGlobalDelete ? Dtor_Complete : Dtor_Deleting; 1359 CGF.CGM.getCXXABI().EmitVirtualDestructorCall(CGF, Dtor, DtorType, 1360 SourceLocation(), Ptr); 1361 1362 if (UseGlobalDelete) { 1363 CGF.PopCleanupBlock(); 1364 } 1365 1366 return; 1367 } 1368 } 1369 } 1370 1371 // Make sure that we call delete even if the dtor throws. 1372 // This doesn't have to a conditional cleanup because we're going 1373 // to pop it off in a second. 1374 CGF.EHStack.pushCleanup<CallObjectDelete>(NormalAndEHCleanup, 1375 Ptr, OperatorDelete, ElementType); 1376 1377 if (Dtor) 1378 CGF.EmitCXXDestructorCall(Dtor, Dtor_Complete, 1379 /*ForVirtualBase=*/false, 1380 /*Delegating=*/false, 1381 Ptr); 1382 else if (CGF.getLangOpts().ObjCAutoRefCount && 1383 ElementType->isObjCLifetimeType()) { 1384 switch (ElementType.getObjCLifetime()) { 1385 case Qualifiers::OCL_None: 1386 case Qualifiers::OCL_ExplicitNone: 1387 case Qualifiers::OCL_Autoreleasing: 1388 break; 1389 1390 case Qualifiers::OCL_Strong: { 1391 // Load the pointer value. 1392 llvm::Value *PtrValue = CGF.Builder.CreateLoad(Ptr, 1393 ElementType.isVolatileQualified()); 1394 1395 CGF.EmitARCRelease(PtrValue, ARCPreciseLifetime); 1396 break; 1397 } 1398 1399 case Qualifiers::OCL_Weak: 1400 CGF.EmitARCDestroyWeak(Ptr); 1401 break; 1402 } 1403 } 1404 1405 CGF.PopCleanupBlock(); 1406} 1407 1408namespace { 1409 /// Calls the given 'operator delete' on an array of objects. 1410 struct CallArrayDelete : EHScopeStack::Cleanup { 1411 llvm::Value *Ptr; 1412 const FunctionDecl *OperatorDelete; 1413 llvm::Value *NumElements; 1414 QualType ElementType; 1415 CharUnits CookieSize; 1416 1417 CallArrayDelete(llvm::Value *Ptr, 1418 const FunctionDecl *OperatorDelete, 1419 llvm::Value *NumElements, 1420 QualType ElementType, 1421 CharUnits CookieSize) 1422 : Ptr(Ptr), OperatorDelete(OperatorDelete), NumElements(NumElements), 1423 ElementType(ElementType), CookieSize(CookieSize) {} 1424 1425 void Emit(CodeGenFunction &CGF, Flags flags) { 1426 const FunctionProtoType *DeleteFTy = 1427 OperatorDelete->getType()->getAs<FunctionProtoType>(); 1428 assert(DeleteFTy->getNumArgs() == 1 || DeleteFTy->getNumArgs() == 2); 1429 1430 CallArgList Args; 1431 1432 // Pass the pointer as the first argument. 1433 QualType VoidPtrTy = DeleteFTy->getArgType(0); 1434 llvm::Value *DeletePtr 1435 = CGF.Builder.CreateBitCast(Ptr, CGF.ConvertType(VoidPtrTy)); 1436 Args.add(RValue::get(DeletePtr), VoidPtrTy); 1437 1438 // Pass the original requested size as the second argument. 1439 if (DeleteFTy->getNumArgs() == 2) { 1440 QualType size_t = DeleteFTy->getArgType(1); 1441 llvm::IntegerType *SizeTy 1442 = cast<llvm::IntegerType>(CGF.ConvertType(size_t)); 1443 1444 CharUnits ElementTypeSize = 1445 CGF.CGM.getContext().getTypeSizeInChars(ElementType); 1446 1447 // The size of an element, multiplied by the number of elements. 1448 llvm::Value *Size 1449 = llvm::ConstantInt::get(SizeTy, ElementTypeSize.getQuantity()); 1450 Size = CGF.Builder.CreateMul(Size, NumElements); 1451 1452 // Plus the size of the cookie if applicable. 1453 if (!CookieSize.isZero()) { 1454 llvm::Value *CookieSizeV 1455 = llvm::ConstantInt::get(SizeTy, CookieSize.getQuantity()); 1456 Size = CGF.Builder.CreateAdd(Size, CookieSizeV); 1457 } 1458 1459 Args.add(RValue::get(Size), size_t); 1460 } 1461 1462 // Emit the call to delete. 1463 EmitNewDeleteCall(CGF, OperatorDelete, DeleteFTy, Args); 1464 } 1465 }; 1466} 1467 1468/// Emit the code for deleting an array of objects. 1469static void EmitArrayDelete(CodeGenFunction &CGF, 1470 const CXXDeleteExpr *E, 1471 llvm::Value *deletedPtr, 1472 QualType elementType) { 1473 llvm::Value *numElements = 0; 1474 llvm::Value *allocatedPtr = 0; 1475 CharUnits cookieSize; 1476 CGF.CGM.getCXXABI().ReadArrayCookie(CGF, deletedPtr, E, elementType, 1477 numElements, allocatedPtr, cookieSize); 1478 1479 assert(allocatedPtr && "ReadArrayCookie didn't set allocated pointer"); 1480 1481 // Make sure that we call delete even if one of the dtors throws. 1482 const FunctionDecl *operatorDelete = E->getOperatorDelete(); 1483 CGF.EHStack.pushCleanup<CallArrayDelete>(NormalAndEHCleanup, 1484 allocatedPtr, operatorDelete, 1485 numElements, elementType, 1486 cookieSize); 1487 1488 // Destroy the elements. 1489 if (QualType::DestructionKind dtorKind = elementType.isDestructedType()) { 1490 assert(numElements && "no element count for a type with a destructor!"); 1491 1492 llvm::Value *arrayEnd = 1493 CGF.Builder.CreateInBoundsGEP(deletedPtr, numElements, "delete.end"); 1494 1495 // Note that it is legal to allocate a zero-length array, and we 1496 // can never fold the check away because the length should always 1497 // come from a cookie. 1498 CGF.emitArrayDestroy(deletedPtr, arrayEnd, elementType, 1499 CGF.getDestroyer(dtorKind), 1500 /*checkZeroLength*/ true, 1501 CGF.needsEHCleanup(dtorKind)); 1502 } 1503 1504 // Pop the cleanup block. 1505 CGF.PopCleanupBlock(); 1506} 1507 1508void CodeGenFunction::EmitCXXDeleteExpr(const CXXDeleteExpr *E) { 1509 const Expr *Arg = E->getArgument(); 1510 llvm::Value *Ptr = EmitScalarExpr(Arg); 1511 1512 // Null check the pointer. 1513 llvm::BasicBlock *DeleteNotNull = createBasicBlock("delete.notnull"); 1514 llvm::BasicBlock *DeleteEnd = createBasicBlock("delete.end"); 1515 1516 llvm::Value *IsNull = Builder.CreateIsNull(Ptr, "isnull"); 1517 1518 Builder.CreateCondBr(IsNull, DeleteEnd, DeleteNotNull); 1519 EmitBlock(DeleteNotNull); 1520 1521 // We might be deleting a pointer to array. If so, GEP down to the 1522 // first non-array element. 1523 // (this assumes that A(*)[3][7] is converted to [3 x [7 x %A]]*) 1524 QualType DeleteTy = Arg->getType()->getAs<PointerType>()->getPointeeType(); 1525 if (DeleteTy->isConstantArrayType()) { 1526 llvm::Value *Zero = Builder.getInt32(0); 1527 SmallVector<llvm::Value*,8> GEP; 1528 1529 GEP.push_back(Zero); // point at the outermost array 1530 1531 // For each layer of array type we're pointing at: 1532 while (const ConstantArrayType *Arr 1533 = getContext().getAsConstantArrayType(DeleteTy)) { 1534 // 1. Unpeel the array type. 1535 DeleteTy = Arr->getElementType(); 1536 1537 // 2. GEP to the first element of the array. 1538 GEP.push_back(Zero); 1539 } 1540 1541 Ptr = Builder.CreateInBoundsGEP(Ptr, GEP, "del.first"); 1542 } 1543 1544 assert(ConvertTypeForMem(DeleteTy) == 1545 cast<llvm::PointerType>(Ptr->getType())->getElementType()); 1546 1547 if (E->isArrayForm()) { 1548 EmitArrayDelete(*this, E, Ptr, DeleteTy); 1549 } else { 1550 EmitObjectDelete(*this, E->getOperatorDelete(), Ptr, DeleteTy, 1551 E->isGlobalDelete()); 1552 } 1553 1554 EmitBlock(DeleteEnd); 1555} 1556 1557static llvm::Constant *getBadTypeidFn(CodeGenFunction &CGF) { 1558 // void __cxa_bad_typeid(); 1559 llvm::FunctionType *FTy = llvm::FunctionType::get(CGF.VoidTy, false); 1560 1561 return CGF.CGM.CreateRuntimeFunction(FTy, "__cxa_bad_typeid"); 1562} 1563 1564static void EmitBadTypeidCall(CodeGenFunction &CGF) { 1565 llvm::Value *Fn = getBadTypeidFn(CGF); 1566 CGF.EmitRuntimeCallOrInvoke(Fn).setDoesNotReturn(); 1567 CGF.Builder.CreateUnreachable(); 1568} 1569 1570static llvm::Value *EmitTypeidFromVTable(CodeGenFunction &CGF, 1571 const Expr *E, 1572 llvm::Type *StdTypeInfoPtrTy) { 1573 // Get the vtable pointer. 1574 llvm::Value *ThisPtr = CGF.EmitLValue(E).getAddress(); 1575 1576 // C++ [expr.typeid]p2: 1577 // If the glvalue expression is obtained by applying the unary * operator to 1578 // a pointer and the pointer is a null pointer value, the typeid expression 1579 // throws the std::bad_typeid exception. 1580 if (const UnaryOperator *UO = dyn_cast<UnaryOperator>(E->IgnoreParens())) { 1581 if (UO->getOpcode() == UO_Deref) { 1582 llvm::BasicBlock *BadTypeidBlock = 1583 CGF.createBasicBlock("typeid.bad_typeid"); 1584 llvm::BasicBlock *EndBlock = 1585 CGF.createBasicBlock("typeid.end"); 1586 1587 llvm::Value *IsNull = CGF.Builder.CreateIsNull(ThisPtr); 1588 CGF.Builder.CreateCondBr(IsNull, BadTypeidBlock, EndBlock); 1589 1590 CGF.EmitBlock(BadTypeidBlock); 1591 EmitBadTypeidCall(CGF); 1592 CGF.EmitBlock(EndBlock); 1593 } 1594 } 1595 1596 llvm::Value *Value = CGF.GetVTablePtr(ThisPtr, 1597 StdTypeInfoPtrTy->getPointerTo()); 1598 1599 // Load the type info. 1600 Value = CGF.Builder.CreateConstInBoundsGEP1_64(Value, -1ULL); 1601 return CGF.Builder.CreateLoad(Value); 1602} 1603 1604llvm::Value *CodeGenFunction::EmitCXXTypeidExpr(const CXXTypeidExpr *E) { 1605 llvm::Type *StdTypeInfoPtrTy = 1606 ConvertType(E->getType())->getPointerTo(); 1607 1608 if (E->isTypeOperand()) { 1609 llvm::Constant *TypeInfo = 1610 CGM.GetAddrOfRTTIDescriptor(E->getTypeOperand(getContext())); 1611 return Builder.CreateBitCast(TypeInfo, StdTypeInfoPtrTy); 1612 } 1613 1614 // C++ [expr.typeid]p2: 1615 // When typeid is applied to a glvalue expression whose type is a 1616 // polymorphic class type, the result refers to a std::type_info object 1617 // representing the type of the most derived object (that is, the dynamic 1618 // type) to which the glvalue refers. 1619 if (E->isPotentiallyEvaluated()) 1620 return EmitTypeidFromVTable(*this, E->getExprOperand(), 1621 StdTypeInfoPtrTy); 1622 1623 QualType OperandTy = E->getExprOperand()->getType(); 1624 return Builder.CreateBitCast(CGM.GetAddrOfRTTIDescriptor(OperandTy), 1625 StdTypeInfoPtrTy); 1626} 1627 1628static llvm::Constant *getDynamicCastFn(CodeGenFunction &CGF) { 1629 // void *__dynamic_cast(const void *sub, 1630 // const abi::__class_type_info *src, 1631 // const abi::__class_type_info *dst, 1632 // std::ptrdiff_t src2dst_offset); 1633 1634 llvm::Type *Int8PtrTy = CGF.Int8PtrTy; 1635 llvm::Type *PtrDiffTy = 1636 CGF.ConvertType(CGF.getContext().getPointerDiffType()); 1637 1638 llvm::Type *Args[4] = { Int8PtrTy, Int8PtrTy, Int8PtrTy, PtrDiffTy }; 1639 1640 llvm::FunctionType *FTy = llvm::FunctionType::get(Int8PtrTy, Args, false); 1641 1642 // Mark the function as nounwind readonly. 1643 llvm::Attribute::AttrKind FuncAttrs[] = { llvm::Attribute::NoUnwind, 1644 llvm::Attribute::ReadOnly }; 1645 llvm::AttributeSet Attrs = llvm::AttributeSet::get( 1646 CGF.getLLVMContext(), llvm::AttributeSet::FunctionIndex, FuncAttrs); 1647 1648 return CGF.CGM.CreateRuntimeFunction(FTy, "__dynamic_cast", Attrs); 1649} 1650 1651static llvm::Constant *getBadCastFn(CodeGenFunction &CGF) { 1652 // void __cxa_bad_cast(); 1653 llvm::FunctionType *FTy = llvm::FunctionType::get(CGF.VoidTy, false); 1654 return CGF.CGM.CreateRuntimeFunction(FTy, "__cxa_bad_cast"); 1655} 1656 1657static void EmitBadCastCall(CodeGenFunction &CGF) { 1658 llvm::Value *Fn = getBadCastFn(CGF); 1659 CGF.EmitRuntimeCallOrInvoke(Fn).setDoesNotReturn(); 1660 CGF.Builder.CreateUnreachable(); 1661} 1662 1663/// \brief Compute the src2dst_offset hint as described in the 1664/// Itanium C++ ABI [2.9.7] 1665static CharUnits computeOffsetHint(ASTContext &Context, 1666 const CXXRecordDecl *Src, 1667 const CXXRecordDecl *Dst) { 1668 CXXBasePaths Paths(/*FindAmbiguities=*/true, /*RecordPaths=*/true, 1669 /*DetectVirtual=*/false); 1670 1671 // If Dst is not derived from Src we can skip the whole computation below and 1672 // return that Src is not a public base of Dst. Record all inheritance paths. 1673 if (!Dst->isDerivedFrom(Src, Paths)) 1674 return CharUnits::fromQuantity(-2ULL); 1675 1676 unsigned NumPublicPaths = 0; 1677 CharUnits Offset; 1678 1679 // Now walk all possible inheritance paths. 1680 for (CXXBasePaths::paths_iterator I = Paths.begin(), E = Paths.end(); 1681 I != E; ++I) { 1682 if (I->Access != AS_public) // Ignore non-public inheritance. 1683 continue; 1684 1685 ++NumPublicPaths; 1686 1687 for (CXXBasePath::iterator J = I->begin(), JE = I->end(); J != JE; ++J) { 1688 // If the path contains a virtual base class we can't give any hint. 1689 // -1: no hint. 1690 if (J->Base->isVirtual()) 1691 return CharUnits::fromQuantity(-1ULL); 1692 1693 if (NumPublicPaths > 1) // Won't use offsets, skip computation. 1694 continue; 1695 1696 // Accumulate the base class offsets. 1697 const ASTRecordLayout &L = Context.getASTRecordLayout(J->Class); 1698 Offset += L.getBaseClassOffset(J->Base->getType()->getAsCXXRecordDecl()); 1699 } 1700 } 1701 1702 // -2: Src is not a public base of Dst. 1703 if (NumPublicPaths == 0) 1704 return CharUnits::fromQuantity(-2ULL); 1705 1706 // -3: Src is a multiple public base type but never a virtual base type. 1707 if (NumPublicPaths > 1) 1708 return CharUnits::fromQuantity(-3ULL); 1709 1710 // Otherwise, the Src type is a unique public nonvirtual base type of Dst. 1711 // Return the offset of Src from the origin of Dst. 1712 return Offset; 1713} 1714 1715static llvm::Value * 1716EmitDynamicCastCall(CodeGenFunction &CGF, llvm::Value *Value, 1717 QualType SrcTy, QualType DestTy, 1718 llvm::BasicBlock *CastEnd) { 1719 llvm::Type *PtrDiffLTy = 1720 CGF.ConvertType(CGF.getContext().getPointerDiffType()); 1721 llvm::Type *DestLTy = CGF.ConvertType(DestTy); 1722 1723 if (const PointerType *PTy = DestTy->getAs<PointerType>()) { 1724 if (PTy->getPointeeType()->isVoidType()) { 1725 // C++ [expr.dynamic.cast]p7: 1726 // If T is "pointer to cv void," then the result is a pointer to the 1727 // most derived object pointed to by v. 1728 1729 // Get the vtable pointer. 1730 llvm::Value *VTable = CGF.GetVTablePtr(Value, PtrDiffLTy->getPointerTo()); 1731 1732 // Get the offset-to-top from the vtable. 1733 llvm::Value *OffsetToTop = 1734 CGF.Builder.CreateConstInBoundsGEP1_64(VTable, -2ULL); 1735 OffsetToTop = CGF.Builder.CreateLoad(OffsetToTop, "offset.to.top"); 1736 1737 // Finally, add the offset to the pointer. 1738 Value = CGF.EmitCastToVoidPtr(Value); 1739 Value = CGF.Builder.CreateInBoundsGEP(Value, OffsetToTop); 1740 1741 return CGF.Builder.CreateBitCast(Value, DestLTy); 1742 } 1743 } 1744 1745 QualType SrcRecordTy; 1746 QualType DestRecordTy; 1747 1748 if (const PointerType *DestPTy = DestTy->getAs<PointerType>()) { 1749 SrcRecordTy = SrcTy->castAs<PointerType>()->getPointeeType(); 1750 DestRecordTy = DestPTy->getPointeeType(); 1751 } else { 1752 SrcRecordTy = SrcTy; 1753 DestRecordTy = DestTy->castAs<ReferenceType>()->getPointeeType(); 1754 } 1755 1756 assert(SrcRecordTy->isRecordType() && "source type must be a record type!"); 1757 assert(DestRecordTy->isRecordType() && "dest type must be a record type!"); 1758 1759 llvm::Value *SrcRTTI = 1760 CGF.CGM.GetAddrOfRTTIDescriptor(SrcRecordTy.getUnqualifiedType()); 1761 llvm::Value *DestRTTI = 1762 CGF.CGM.GetAddrOfRTTIDescriptor(DestRecordTy.getUnqualifiedType()); 1763 1764 // Compute the offset hint. 1765 const CXXRecordDecl *SrcDecl = SrcRecordTy->getAsCXXRecordDecl(); 1766 const CXXRecordDecl *DestDecl = DestRecordTy->getAsCXXRecordDecl(); 1767 llvm::Value *OffsetHint = 1768 llvm::ConstantInt::get(PtrDiffLTy, 1769 computeOffsetHint(CGF.getContext(), SrcDecl, 1770 DestDecl).getQuantity()); 1771 1772 // Emit the call to __dynamic_cast. 1773 Value = CGF.EmitCastToVoidPtr(Value); 1774 1775 llvm::Value *args[] = { Value, SrcRTTI, DestRTTI, OffsetHint }; 1776 Value = CGF.EmitNounwindRuntimeCall(getDynamicCastFn(CGF), args); 1777 Value = CGF.Builder.CreateBitCast(Value, DestLTy); 1778 1779 /// C++ [expr.dynamic.cast]p9: 1780 /// A failed cast to reference type throws std::bad_cast 1781 if (DestTy->isReferenceType()) { 1782 llvm::BasicBlock *BadCastBlock = 1783 CGF.createBasicBlock("dynamic_cast.bad_cast"); 1784 1785 llvm::Value *IsNull = CGF.Builder.CreateIsNull(Value); 1786 CGF.Builder.CreateCondBr(IsNull, BadCastBlock, CastEnd); 1787 1788 CGF.EmitBlock(BadCastBlock); 1789 EmitBadCastCall(CGF); 1790 } 1791 1792 return Value; 1793} 1794 1795static llvm::Value *EmitDynamicCastToNull(CodeGenFunction &CGF, 1796 QualType DestTy) { 1797 llvm::Type *DestLTy = CGF.ConvertType(DestTy); 1798 if (DestTy->isPointerType()) 1799 return llvm::Constant::getNullValue(DestLTy); 1800 1801 /// C++ [expr.dynamic.cast]p9: 1802 /// A failed cast to reference type throws std::bad_cast 1803 EmitBadCastCall(CGF); 1804 1805 CGF.EmitBlock(CGF.createBasicBlock("dynamic_cast.end")); 1806 return llvm::UndefValue::get(DestLTy); 1807} 1808 1809llvm::Value *CodeGenFunction::EmitDynamicCast(llvm::Value *Value, 1810 const CXXDynamicCastExpr *DCE) { 1811 QualType DestTy = DCE->getTypeAsWritten(); 1812 1813 if (DCE->isAlwaysNull()) 1814 return EmitDynamicCastToNull(*this, DestTy); 1815 1816 QualType SrcTy = DCE->getSubExpr()->getType(); 1817 1818 // C++ [expr.dynamic.cast]p4: 1819 // If the value of v is a null pointer value in the pointer case, the result 1820 // is the null pointer value of type T. 1821 bool ShouldNullCheckSrcValue = SrcTy->isPointerType(); 1822 1823 llvm::BasicBlock *CastNull = 0; 1824 llvm::BasicBlock *CastNotNull = 0; 1825 llvm::BasicBlock *CastEnd = createBasicBlock("dynamic_cast.end"); 1826 1827 if (ShouldNullCheckSrcValue) { 1828 CastNull = createBasicBlock("dynamic_cast.null"); 1829 CastNotNull = createBasicBlock("dynamic_cast.notnull"); 1830 1831 llvm::Value *IsNull = Builder.CreateIsNull(Value); 1832 Builder.CreateCondBr(IsNull, CastNull, CastNotNull); 1833 EmitBlock(CastNotNull); 1834 } 1835 1836 Value = EmitDynamicCastCall(*this, Value, SrcTy, DestTy, CastEnd); 1837 1838 if (ShouldNullCheckSrcValue) { 1839 EmitBranch(CastEnd); 1840 1841 EmitBlock(CastNull); 1842 EmitBranch(CastEnd); 1843 } 1844 1845 EmitBlock(CastEnd); 1846 1847 if (ShouldNullCheckSrcValue) { 1848 llvm::PHINode *PHI = Builder.CreatePHI(Value->getType(), 2); 1849 PHI->addIncoming(Value, CastNotNull); 1850 PHI->addIncoming(llvm::Constant::getNullValue(Value->getType()), CastNull); 1851 1852 Value = PHI; 1853 } 1854 1855 return Value; 1856} 1857 1858void CodeGenFunction::EmitLambdaExpr(const LambdaExpr *E, AggValueSlot Slot) { 1859 RunCleanupsScope Scope(*this); 1860 LValue SlotLV = MakeAddrLValue(Slot.getAddr(), E->getType(), 1861 Slot.getAlignment()); 1862 1863 CXXRecordDecl::field_iterator CurField = E->getLambdaClass()->field_begin(); 1864 for (LambdaExpr::capture_init_iterator i = E->capture_init_begin(), 1865 e = E->capture_init_end(); 1866 i != e; ++i, ++CurField) { 1867 // Emit initialization 1868 1869 LValue LV = EmitLValueForFieldInitialization(SlotLV, *CurField); 1870 ArrayRef<VarDecl *> ArrayIndexes; 1871 if (CurField->getType()->isArrayType()) 1872 ArrayIndexes = E->getCaptureInitIndexVars(i); 1873 EmitInitializerForField(*CurField, LV, *i, ArrayIndexes); 1874 } 1875} 1876