CGExprCXX.cpp revision 6bcf27bb9a4b5c3f79cb44c0e4654a6d7619ad89
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 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 = nullptr; 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 = nullptr; 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->getReturnType().getCanonicalType() != 123 MD->getReturnType().getCanonicalType()) 124 DevirtualizedMethod = nullptr; 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(nullptr); 136 if (isa<CXXConstructorDecl>(MD) && 137 cast<CXXConstructorDecl>(MD)->isDefaultConstructor()) 138 return RValue::get(nullptr); 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 = nullptr; 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=*/nullptr, QualType(), nullptr,nullptr); 203 } 204 return RValue::get(nullptr); 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().adjustThisArgumentForVirtualFunctionCall( 225 *this, MD, This, UseVirtualCall); 226 } 227 228 return EmitCXXMemberCall(MD, CE->getExprLoc(), Callee, ReturnValue, This, 229 /*ImplicitParam=*/nullptr, QualType(), 230 CE->arg_begin(), CE->arg_end()); 231} 232 233RValue 234CodeGenFunction::EmitCXXMemberPointerCallExpr(const CXXMemberCallExpr *E, 235 ReturnValueSlot ReturnValue) { 236 const BinaryOperator *BO = 237 cast<BinaryOperator>(E->getCallee()->IgnoreParens()); 238 const Expr *BaseExpr = BO->getLHS(); 239 const Expr *MemFnExpr = BO->getRHS(); 240 241 const MemberPointerType *MPT = 242 MemFnExpr->getType()->castAs<MemberPointerType>(); 243 244 const FunctionProtoType *FPT = 245 MPT->getPointeeType()->castAs<FunctionProtoType>(); 246 const CXXRecordDecl *RD = 247 cast<CXXRecordDecl>(MPT->getClass()->getAs<RecordType>()->getDecl()); 248 249 // Get the member function pointer. 250 llvm::Value *MemFnPtr = EmitScalarExpr(MemFnExpr); 251 252 // Emit the 'this' pointer. 253 llvm::Value *This; 254 255 if (BO->getOpcode() == BO_PtrMemI) 256 This = EmitScalarExpr(BaseExpr); 257 else 258 This = EmitLValue(BaseExpr).getAddress(); 259 260 EmitTypeCheck(TCK_MemberCall, E->getExprLoc(), This, 261 QualType(MPT->getClass(), 0)); 262 263 // Ask the ABI to load the callee. Note that This is modified. 264 llvm::Value *Callee = 265 CGM.getCXXABI().EmitLoadOfMemberFunctionPointer(*this, BO, This, MemFnPtr, MPT); 266 267 CallArgList Args; 268 269 QualType ThisType = 270 getContext().getPointerType(getContext().getTagDeclType(RD)); 271 272 // Push the this ptr. 273 Args.add(RValue::get(This), ThisType); 274 275 RequiredArgs required = RequiredArgs::forPrototypePlus(FPT, 1); 276 277 // And the rest of the call args 278 EmitCallArgs(Args, FPT, E->arg_begin(), E->arg_end()); 279 return EmitCall(CGM.getTypes().arrangeCXXMethodCall(Args, FPT, required), 280 Callee, ReturnValue, Args); 281} 282 283RValue 284CodeGenFunction::EmitCXXOperatorMemberCallExpr(const CXXOperatorCallExpr *E, 285 const CXXMethodDecl *MD, 286 ReturnValueSlot ReturnValue) { 287 assert(MD->isInstance() && 288 "Trying to emit a member call expr on a static method!"); 289 LValue LV = EmitLValue(E->getArg(0)); 290 llvm::Value *This = LV.getAddress(); 291 292 if ((MD->isCopyAssignmentOperator() || MD->isMoveAssignmentOperator()) && 293 MD->isTrivial()) { 294 llvm::Value *Src = EmitLValue(E->getArg(1)).getAddress(); 295 QualType Ty = E->getType(); 296 EmitAggregateAssign(This, Src, Ty); 297 return RValue::get(This); 298 } 299 300 llvm::Value *Callee = EmitCXXOperatorMemberCallee(E, MD, This); 301 return EmitCXXMemberCall(MD, E->getExprLoc(), Callee, ReturnValue, This, 302 /*ImplicitParam=*/nullptr, QualType(), 303 E->arg_begin() + 1, E->arg_end()); 304} 305 306RValue CodeGenFunction::EmitCUDAKernelCallExpr(const CUDAKernelCallExpr *E, 307 ReturnValueSlot ReturnValue) { 308 return CGM.getCUDARuntime().EmitCUDAKernelCallExpr(*this, E, ReturnValue); 309} 310 311static void EmitNullBaseClassInitialization(CodeGenFunction &CGF, 312 llvm::Value *DestPtr, 313 const CXXRecordDecl *Base) { 314 if (Base->isEmpty()) 315 return; 316 317 DestPtr = CGF.EmitCastToVoidPtr(DestPtr); 318 319 const ASTRecordLayout &Layout = CGF.getContext().getASTRecordLayout(Base); 320 CharUnits Size = Layout.getNonVirtualSize(); 321 CharUnits Align = Layout.getNonVirtualAlignment(); 322 323 llvm::Value *SizeVal = CGF.CGM.getSize(Size); 324 325 // If the type contains a pointer to data member we can't memset it to zero. 326 // Instead, create a null constant and copy it to the destination. 327 // TODO: there are other patterns besides zero that we can usefully memset, 328 // like -1, which happens to be the pattern used by member-pointers. 329 // TODO: isZeroInitializable can be over-conservative in the case where a 330 // virtual base contains a member pointer. 331 if (!CGF.CGM.getTypes().isZeroInitializable(Base)) { 332 llvm::Constant *NullConstant = CGF.CGM.EmitNullConstantForBase(Base); 333 334 llvm::GlobalVariable *NullVariable = 335 new llvm::GlobalVariable(CGF.CGM.getModule(), NullConstant->getType(), 336 /*isConstant=*/true, 337 llvm::GlobalVariable::PrivateLinkage, 338 NullConstant, Twine()); 339 NullVariable->setAlignment(Align.getQuantity()); 340 llvm::Value *SrcPtr = CGF.EmitCastToVoidPtr(NullVariable); 341 342 // Get and call the appropriate llvm.memcpy overload. 343 CGF.Builder.CreateMemCpy(DestPtr, SrcPtr, SizeVal, Align.getQuantity()); 344 return; 345 } 346 347 // Otherwise, just memset the whole thing to zero. This is legal 348 // because in LLVM, all default initializers (other than the ones we just 349 // handled above) are guaranteed to have a bit pattern of all zeros. 350 CGF.Builder.CreateMemSet(DestPtr, CGF.Builder.getInt8(0), SizeVal, 351 Align.getQuantity()); 352} 353 354void 355CodeGenFunction::EmitCXXConstructExpr(const CXXConstructExpr *E, 356 AggValueSlot Dest) { 357 assert(!Dest.isIgnored() && "Must have a destination!"); 358 const CXXConstructorDecl *CD = E->getConstructor(); 359 360 // If we require zero initialization before (or instead of) calling the 361 // constructor, as can be the case with a non-user-provided default 362 // constructor, emit the zero initialization now, unless destination is 363 // already zeroed. 364 if (E->requiresZeroInitialization() && !Dest.isZeroed()) { 365 switch (E->getConstructionKind()) { 366 case CXXConstructExpr::CK_Delegating: 367 case CXXConstructExpr::CK_Complete: 368 EmitNullInitialization(Dest.getAddr(), E->getType()); 369 break; 370 case CXXConstructExpr::CK_VirtualBase: 371 case CXXConstructExpr::CK_NonVirtualBase: 372 EmitNullBaseClassInitialization(*this, Dest.getAddr(), CD->getParent()); 373 break; 374 } 375 } 376 377 // If this is a call to a trivial default constructor, do nothing. 378 if (CD->isTrivial() && CD->isDefaultConstructor()) 379 return; 380 381 // Elide the constructor if we're constructing from a temporary. 382 // The temporary check is required because Sema sets this on NRVO 383 // returns. 384 if (getLangOpts().ElideConstructors && E->isElidable()) { 385 assert(getContext().hasSameUnqualifiedType(E->getType(), 386 E->getArg(0)->getType())); 387 if (E->getArg(0)->isTemporaryObject(getContext(), CD->getParent())) { 388 EmitAggExpr(E->getArg(0), Dest); 389 return; 390 } 391 } 392 393 if (const ConstantArrayType *arrayType 394 = getContext().getAsConstantArrayType(E->getType())) { 395 EmitCXXAggrConstructorCall(CD, arrayType, Dest.getAddr(), 396 E->arg_begin(), E->arg_end()); 397 } else { 398 CXXCtorType Type = Ctor_Complete; 399 bool ForVirtualBase = false; 400 bool Delegating = false; 401 402 switch (E->getConstructionKind()) { 403 case CXXConstructExpr::CK_Delegating: 404 // We should be emitting a constructor; GlobalDecl will assert this 405 Type = CurGD.getCtorType(); 406 Delegating = true; 407 break; 408 409 case CXXConstructExpr::CK_Complete: 410 Type = Ctor_Complete; 411 break; 412 413 case CXXConstructExpr::CK_VirtualBase: 414 ForVirtualBase = true; 415 // fall-through 416 417 case CXXConstructExpr::CK_NonVirtualBase: 418 Type = Ctor_Base; 419 } 420 421 // Call the constructor. 422 EmitCXXConstructorCall(CD, Type, ForVirtualBase, Delegating, Dest.getAddr(), 423 E->arg_begin(), E->arg_end()); 424 } 425} 426 427void 428CodeGenFunction::EmitSynthesizedCXXCopyCtor(llvm::Value *Dest, 429 llvm::Value *Src, 430 const Expr *Exp) { 431 if (const ExprWithCleanups *E = dyn_cast<ExprWithCleanups>(Exp)) 432 Exp = E->getSubExpr(); 433 assert(isa<CXXConstructExpr>(Exp) && 434 "EmitSynthesizedCXXCopyCtor - unknown copy ctor expr"); 435 const CXXConstructExpr* E = cast<CXXConstructExpr>(Exp); 436 const CXXConstructorDecl *CD = E->getConstructor(); 437 RunCleanupsScope Scope(*this); 438 439 // If we require zero initialization before (or instead of) calling the 440 // constructor, as can be the case with a non-user-provided default 441 // constructor, emit the zero initialization now. 442 // FIXME. Do I still need this for a copy ctor synthesis? 443 if (E->requiresZeroInitialization()) 444 EmitNullInitialization(Dest, E->getType()); 445 446 assert(!getContext().getAsConstantArrayType(E->getType()) 447 && "EmitSynthesizedCXXCopyCtor - Copied-in Array"); 448 EmitSynthesizedCXXCopyCtorCall(CD, Dest, Src, E->arg_begin(), E->arg_end()); 449} 450 451static CharUnits CalculateCookiePadding(CodeGenFunction &CGF, 452 const CXXNewExpr *E) { 453 if (!E->isArray()) 454 return CharUnits::Zero(); 455 456 // No cookie is required if the operator new[] being used is the 457 // reserved placement operator new[]. 458 if (E->getOperatorNew()->isReservedGlobalPlacementOperator()) 459 return CharUnits::Zero(); 460 461 return CGF.CGM.getCXXABI().GetArrayCookieSize(E); 462} 463 464static llvm::Value *EmitCXXNewAllocSize(CodeGenFunction &CGF, 465 const CXXNewExpr *e, 466 unsigned minElements, 467 llvm::Value *&numElements, 468 llvm::Value *&sizeWithoutCookie) { 469 QualType type = e->getAllocatedType(); 470 471 if (!e->isArray()) { 472 CharUnits typeSize = CGF.getContext().getTypeSizeInChars(type); 473 sizeWithoutCookie 474 = llvm::ConstantInt::get(CGF.SizeTy, typeSize.getQuantity()); 475 return sizeWithoutCookie; 476 } 477 478 // The width of size_t. 479 unsigned sizeWidth = CGF.SizeTy->getBitWidth(); 480 481 // Figure out the cookie size. 482 llvm::APInt cookieSize(sizeWidth, 483 CalculateCookiePadding(CGF, e).getQuantity()); 484 485 // Emit the array size expression. 486 // We multiply the size of all dimensions for NumElements. 487 // e.g for 'int[2][3]', ElemType is 'int' and NumElements is 6. 488 numElements = CGF.EmitScalarExpr(e->getArraySize()); 489 assert(isa<llvm::IntegerType>(numElements->getType())); 490 491 // The number of elements can be have an arbitrary integer type; 492 // essentially, we need to multiply it by a constant factor, add a 493 // cookie size, and verify that the result is representable as a 494 // size_t. That's just a gloss, though, and it's wrong in one 495 // important way: if the count is negative, it's an error even if 496 // the cookie size would bring the total size >= 0. 497 bool isSigned 498 = e->getArraySize()->getType()->isSignedIntegerOrEnumerationType(); 499 llvm::IntegerType *numElementsType 500 = cast<llvm::IntegerType>(numElements->getType()); 501 unsigned numElementsWidth = numElementsType->getBitWidth(); 502 503 // Compute the constant factor. 504 llvm::APInt arraySizeMultiplier(sizeWidth, 1); 505 while (const ConstantArrayType *CAT 506 = CGF.getContext().getAsConstantArrayType(type)) { 507 type = CAT->getElementType(); 508 arraySizeMultiplier *= CAT->getSize(); 509 } 510 511 CharUnits typeSize = CGF.getContext().getTypeSizeInChars(type); 512 llvm::APInt typeSizeMultiplier(sizeWidth, typeSize.getQuantity()); 513 typeSizeMultiplier *= arraySizeMultiplier; 514 515 // This will be a size_t. 516 llvm::Value *size; 517 518 // If someone is doing 'new int[42]' there is no need to do a dynamic check. 519 // Don't bloat the -O0 code. 520 if (llvm::ConstantInt *numElementsC = 521 dyn_cast<llvm::ConstantInt>(numElements)) { 522 const llvm::APInt &count = numElementsC->getValue(); 523 524 bool hasAnyOverflow = false; 525 526 // If 'count' was a negative number, it's an overflow. 527 if (isSigned && count.isNegative()) 528 hasAnyOverflow = true; 529 530 // We want to do all this arithmetic in size_t. If numElements is 531 // wider than that, check whether it's already too big, and if so, 532 // overflow. 533 else if (numElementsWidth > sizeWidth && 534 numElementsWidth - sizeWidth > count.countLeadingZeros()) 535 hasAnyOverflow = true; 536 537 // Okay, compute a count at the right width. 538 llvm::APInt adjustedCount = count.zextOrTrunc(sizeWidth); 539 540 // If there is a brace-initializer, we cannot allocate fewer elements than 541 // there are initializers. If we do, that's treated like an overflow. 542 if (adjustedCount.ult(minElements)) 543 hasAnyOverflow = true; 544 545 // Scale numElements by that. This might overflow, but we don't 546 // care because it only overflows if allocationSize does, too, and 547 // if that overflows then we shouldn't use this. 548 numElements = llvm::ConstantInt::get(CGF.SizeTy, 549 adjustedCount * arraySizeMultiplier); 550 551 // Compute the size before cookie, and track whether it overflowed. 552 bool overflow; 553 llvm::APInt allocationSize 554 = adjustedCount.umul_ov(typeSizeMultiplier, overflow); 555 hasAnyOverflow |= overflow; 556 557 // Add in the cookie, and check whether it's overflowed. 558 if (cookieSize != 0) { 559 // Save the current size without a cookie. This shouldn't be 560 // used if there was overflow. 561 sizeWithoutCookie = llvm::ConstantInt::get(CGF.SizeTy, allocationSize); 562 563 allocationSize = allocationSize.uadd_ov(cookieSize, overflow); 564 hasAnyOverflow |= overflow; 565 } 566 567 // On overflow, produce a -1 so operator new will fail. 568 if (hasAnyOverflow) { 569 size = llvm::Constant::getAllOnesValue(CGF.SizeTy); 570 } else { 571 size = llvm::ConstantInt::get(CGF.SizeTy, allocationSize); 572 } 573 574 // Otherwise, we might need to use the overflow intrinsics. 575 } else { 576 // There are up to five conditions we need to test for: 577 // 1) if isSigned, we need to check whether numElements is negative; 578 // 2) if numElementsWidth > sizeWidth, we need to check whether 579 // numElements is larger than something representable in size_t; 580 // 3) if minElements > 0, we need to check whether numElements is smaller 581 // than that. 582 // 4) we need to compute 583 // sizeWithoutCookie := numElements * typeSizeMultiplier 584 // and check whether it overflows; and 585 // 5) if we need a cookie, we need to compute 586 // size := sizeWithoutCookie + cookieSize 587 // and check whether it overflows. 588 589 llvm::Value *hasOverflow = nullptr; 590 591 // If numElementsWidth > sizeWidth, then one way or another, we're 592 // going to have to do a comparison for (2), and this happens to 593 // take care of (1), too. 594 if (numElementsWidth > sizeWidth) { 595 llvm::APInt threshold(numElementsWidth, 1); 596 threshold <<= sizeWidth; 597 598 llvm::Value *thresholdV 599 = llvm::ConstantInt::get(numElementsType, threshold); 600 601 hasOverflow = CGF.Builder.CreateICmpUGE(numElements, thresholdV); 602 numElements = CGF.Builder.CreateTrunc(numElements, CGF.SizeTy); 603 604 // Otherwise, if we're signed, we want to sext up to size_t. 605 } else if (isSigned) { 606 if (numElementsWidth < sizeWidth) 607 numElements = CGF.Builder.CreateSExt(numElements, CGF.SizeTy); 608 609 // If there's a non-1 type size multiplier, then we can do the 610 // signedness check at the same time as we do the multiply 611 // because a negative number times anything will cause an 612 // unsigned overflow. Otherwise, we have to do it here. But at least 613 // in this case, we can subsume the >= minElements check. 614 if (typeSizeMultiplier == 1) 615 hasOverflow = CGF.Builder.CreateICmpSLT(numElements, 616 llvm::ConstantInt::get(CGF.SizeTy, minElements)); 617 618 // Otherwise, zext up to size_t if necessary. 619 } else if (numElementsWidth < sizeWidth) { 620 numElements = CGF.Builder.CreateZExt(numElements, CGF.SizeTy); 621 } 622 623 assert(numElements->getType() == CGF.SizeTy); 624 625 if (minElements) { 626 // Don't allow allocation of fewer elements than we have initializers. 627 if (!hasOverflow) { 628 hasOverflow = CGF.Builder.CreateICmpULT(numElements, 629 llvm::ConstantInt::get(CGF.SizeTy, minElements)); 630 } else if (numElementsWidth > sizeWidth) { 631 // The other existing overflow subsumes this check. 632 // We do an unsigned comparison, since any signed value < -1 is 633 // taken care of either above or below. 634 hasOverflow = CGF.Builder.CreateOr(hasOverflow, 635 CGF.Builder.CreateICmpULT(numElements, 636 llvm::ConstantInt::get(CGF.SizeTy, minElements))); 637 } 638 } 639 640 size = numElements; 641 642 // Multiply by the type size if necessary. This multiplier 643 // includes all the factors for nested arrays. 644 // 645 // This step also causes numElements to be scaled up by the 646 // nested-array factor if necessary. Overflow on this computation 647 // can be ignored because the result shouldn't be used if 648 // allocation fails. 649 if (typeSizeMultiplier != 1) { 650 llvm::Value *umul_with_overflow 651 = CGF.CGM.getIntrinsic(llvm::Intrinsic::umul_with_overflow, CGF.SizeTy); 652 653 llvm::Value *tsmV = 654 llvm::ConstantInt::get(CGF.SizeTy, typeSizeMultiplier); 655 llvm::Value *result = 656 CGF.Builder.CreateCall2(umul_with_overflow, size, tsmV); 657 658 llvm::Value *overflowed = CGF.Builder.CreateExtractValue(result, 1); 659 if (hasOverflow) 660 hasOverflow = CGF.Builder.CreateOr(hasOverflow, overflowed); 661 else 662 hasOverflow = overflowed; 663 664 size = CGF.Builder.CreateExtractValue(result, 0); 665 666 // Also scale up numElements by the array size multiplier. 667 if (arraySizeMultiplier != 1) { 668 // If the base element type size is 1, then we can re-use the 669 // multiply we just did. 670 if (typeSize.isOne()) { 671 assert(arraySizeMultiplier == typeSizeMultiplier); 672 numElements = size; 673 674 // Otherwise we need a separate multiply. 675 } else { 676 llvm::Value *asmV = 677 llvm::ConstantInt::get(CGF.SizeTy, arraySizeMultiplier); 678 numElements = CGF.Builder.CreateMul(numElements, asmV); 679 } 680 } 681 } else { 682 // numElements doesn't need to be scaled. 683 assert(arraySizeMultiplier == 1); 684 } 685 686 // Add in the cookie size if necessary. 687 if (cookieSize != 0) { 688 sizeWithoutCookie = size; 689 690 llvm::Value *uadd_with_overflow 691 = CGF.CGM.getIntrinsic(llvm::Intrinsic::uadd_with_overflow, CGF.SizeTy); 692 693 llvm::Value *cookieSizeV = llvm::ConstantInt::get(CGF.SizeTy, cookieSize); 694 llvm::Value *result = 695 CGF.Builder.CreateCall2(uadd_with_overflow, size, cookieSizeV); 696 697 llvm::Value *overflowed = CGF.Builder.CreateExtractValue(result, 1); 698 if (hasOverflow) 699 hasOverflow = CGF.Builder.CreateOr(hasOverflow, overflowed); 700 else 701 hasOverflow = overflowed; 702 703 size = CGF.Builder.CreateExtractValue(result, 0); 704 } 705 706 // If we had any possibility of dynamic overflow, make a select to 707 // overwrite 'size' with an all-ones value, which should cause 708 // operator new to throw. 709 if (hasOverflow) 710 size = CGF.Builder.CreateSelect(hasOverflow, 711 llvm::Constant::getAllOnesValue(CGF.SizeTy), 712 size); 713 } 714 715 if (cookieSize == 0) 716 sizeWithoutCookie = size; 717 else 718 assert(sizeWithoutCookie && "didn't set sizeWithoutCookie?"); 719 720 return size; 721} 722 723static void StoreAnyExprIntoOneUnit(CodeGenFunction &CGF, const Expr *Init, 724 QualType AllocType, llvm::Value *NewPtr) { 725 // FIXME: Refactor with EmitExprAsInit. 726 CharUnits Alignment = CGF.getContext().getTypeAlignInChars(AllocType); 727 switch (CGF.getEvaluationKind(AllocType)) { 728 case TEK_Scalar: 729 CGF.EmitScalarInit(Init, nullptr, CGF.MakeAddrLValue(NewPtr, AllocType, 730 Alignment), 731 false); 732 return; 733 case TEK_Complex: 734 CGF.EmitComplexExprIntoLValue(Init, CGF.MakeAddrLValue(NewPtr, AllocType, 735 Alignment), 736 /*isInit*/ true); 737 return; 738 case TEK_Aggregate: { 739 AggValueSlot Slot 740 = AggValueSlot::forAddr(NewPtr, Alignment, AllocType.getQualifiers(), 741 AggValueSlot::IsDestructed, 742 AggValueSlot::DoesNotNeedGCBarriers, 743 AggValueSlot::IsNotAliased); 744 CGF.EmitAggExpr(Init, Slot); 745 return; 746 } 747 } 748 llvm_unreachable("bad evaluation kind"); 749} 750 751void 752CodeGenFunction::EmitNewArrayInitializer(const CXXNewExpr *E, 753 QualType elementType, 754 llvm::Value *beginPtr, 755 llvm::Value *numElements) { 756 if (!E->hasInitializer()) 757 return; // We have a POD type. 758 759 llvm::Value *explicitPtr = beginPtr; 760 // Find the end of the array, hoisted out of the loop. 761 llvm::Value *endPtr = 762 Builder.CreateInBoundsGEP(beginPtr, numElements, "array.end"); 763 764 unsigned initializerElements = 0; 765 766 const Expr *Init = E->getInitializer(); 767 llvm::AllocaInst *endOfInit = nullptr; 768 QualType::DestructionKind dtorKind = elementType.isDestructedType(); 769 EHScopeStack::stable_iterator cleanup; 770 llvm::Instruction *cleanupDominator = nullptr; 771 772 // If the initializer is an initializer list, first do the explicit elements. 773 if (const InitListExpr *ILE = dyn_cast<InitListExpr>(Init)) { 774 initializerElements = ILE->getNumInits(); 775 776 // If this is a multi-dimensional array new, we will initialize multiple 777 // elements with each init list element. 778 QualType AllocType = E->getAllocatedType(); 779 if (const ConstantArrayType *CAT = dyn_cast_or_null<ConstantArrayType>( 780 AllocType->getAsArrayTypeUnsafe())) { 781 unsigned AS = explicitPtr->getType()->getPointerAddressSpace(); 782 llvm::Type *AllocPtrTy = ConvertTypeForMem(AllocType)->getPointerTo(AS); 783 explicitPtr = Builder.CreateBitCast(explicitPtr, AllocPtrTy); 784 initializerElements *= getContext().getConstantArrayElementCount(CAT); 785 } 786 787 // Enter a partial-destruction cleanup if necessary. 788 if (needsEHCleanup(dtorKind)) { 789 // In principle we could tell the cleanup where we are more 790 // directly, but the control flow can get so varied here that it 791 // would actually be quite complex. Therefore we go through an 792 // alloca. 793 endOfInit = CreateTempAlloca(beginPtr->getType(), "array.endOfInit"); 794 cleanupDominator = Builder.CreateStore(beginPtr, endOfInit); 795 pushIrregularPartialArrayCleanup(beginPtr, endOfInit, elementType, 796 getDestroyer(dtorKind)); 797 cleanup = EHStack.stable_begin(); 798 } 799 800 for (unsigned i = 0, e = ILE->getNumInits(); i != e; ++i) { 801 // Tell the cleanup that it needs to destroy up to this 802 // element. TODO: some of these stores can be trivially 803 // observed to be unnecessary. 804 if (endOfInit) Builder.CreateStore(explicitPtr, endOfInit); 805 StoreAnyExprIntoOneUnit(*this, ILE->getInit(i), 806 ILE->getInit(i)->getType(), explicitPtr); 807 explicitPtr = Builder.CreateConstGEP1_32(explicitPtr, 1, 808 "array.exp.next"); 809 } 810 811 // The remaining elements are filled with the array filler expression. 812 Init = ILE->getArrayFiller(); 813 814 explicitPtr = Builder.CreateBitCast(explicitPtr, beginPtr->getType()); 815 } 816 817 llvm::ConstantInt *constNum = dyn_cast<llvm::ConstantInt>(numElements); 818 819 // If all elements have already been initialized, skip the whole loop. 820 if (constNum && constNum->getZExtValue() <= initializerElements) { 821 // If there was a cleanup, deactivate it. 822 if (cleanupDominator) 823 DeactivateCleanupBlock(cleanup, cleanupDominator); 824 return; 825 } 826 827 // Create the continuation block. 828 llvm::BasicBlock *contBB = createBasicBlock("new.loop.end"); 829 830 // If the number of elements isn't constant, we have to now check if there is 831 // anything left to initialize. 832 if (!constNum) { 833 llvm::BasicBlock *nonEmptyBB = createBasicBlock("new.loop.nonempty"); 834 llvm::Value *isEmpty = Builder.CreateICmpEQ(explicitPtr, endPtr, 835 "array.isempty"); 836 Builder.CreateCondBr(isEmpty, contBB, nonEmptyBB); 837 EmitBlock(nonEmptyBB); 838 } 839 840 // Enter the loop. 841 llvm::BasicBlock *entryBB = Builder.GetInsertBlock(); 842 llvm::BasicBlock *loopBB = createBasicBlock("new.loop"); 843 844 EmitBlock(loopBB); 845 846 // Set up the current-element phi. 847 llvm::PHINode *curPtr = 848 Builder.CreatePHI(explicitPtr->getType(), 2, "array.cur"); 849 curPtr->addIncoming(explicitPtr, entryBB); 850 851 // Store the new cleanup position for irregular cleanups. 852 if (endOfInit) Builder.CreateStore(curPtr, endOfInit); 853 854 // Enter a partial-destruction cleanup if necessary. 855 if (!cleanupDominator && needsEHCleanup(dtorKind)) { 856 pushRegularPartialArrayCleanup(beginPtr, curPtr, elementType, 857 getDestroyer(dtorKind)); 858 cleanup = EHStack.stable_begin(); 859 cleanupDominator = Builder.CreateUnreachable(); 860 } 861 862 // Emit the initializer into this element. 863 StoreAnyExprIntoOneUnit(*this, Init, E->getAllocatedType(), curPtr); 864 865 // Leave the cleanup if we entered one. 866 if (cleanupDominator) { 867 DeactivateCleanupBlock(cleanup, cleanupDominator); 868 cleanupDominator->eraseFromParent(); 869 } 870 871 // FIXME: The code below intends to initialize the individual array base 872 // elements, one at a time - but when dealing with multi-dimensional arrays - 873 // the pointer arithmetic can get confused - so the fix below entails casting 874 // to the allocated type to ensure that we get the pointer arithmetic right. 875 // It seems like the right approach here, it to really initialize the 876 // individual array base elements one at a time since it'll generate less 877 // code. I think the problem is that the wrong type is being passed into 878 // StoreAnyExprIntoOneUnit, but directly fixing that doesn't really work, 879 // because the Init expression has the wrong type at this point. 880 // So... this is ok for a quick fix, but we can and should do a lot better 881 // here long-term. 882 883 // Advance to the next element by adjusting the pointer type as necessary. 884 // For new int[10][20][30], alloc type is int[20][30], base type is 'int'. 885 QualType AllocType = E->getAllocatedType(); 886 llvm::Type *AllocPtrTy = ConvertTypeForMem(AllocType)->getPointerTo( 887 curPtr->getType()->getPointerAddressSpace()); 888 llvm::Value *curPtrAllocTy = Builder.CreateBitCast(curPtr, AllocPtrTy); 889 llvm::Value *nextPtrAllocTy = 890 Builder.CreateConstGEP1_32(curPtrAllocTy, 1, "array.next"); 891 // Cast it back to the base type so that we can compare it to the endPtr. 892 llvm::Value *nextPtr = 893 Builder.CreateBitCast(nextPtrAllocTy, endPtr->getType()); 894 // Check whether we've gotten to the end of the array and, if so, 895 // exit the loop. 896 llvm::Value *isEnd = Builder.CreateICmpEQ(nextPtr, endPtr, "array.atend"); 897 Builder.CreateCondBr(isEnd, contBB, loopBB); 898 curPtr->addIncoming(nextPtr, Builder.GetInsertBlock()); 899 900 EmitBlock(contBB); 901} 902 903static void EmitZeroMemSet(CodeGenFunction &CGF, QualType T, 904 llvm::Value *NewPtr, llvm::Value *Size) { 905 CGF.EmitCastToVoidPtr(NewPtr); 906 CharUnits Alignment = CGF.getContext().getTypeAlignInChars(T); 907 CGF.Builder.CreateMemSet(NewPtr, CGF.Builder.getInt8(0), Size, 908 Alignment.getQuantity(), false); 909} 910 911static void EmitNewInitializer(CodeGenFunction &CGF, const CXXNewExpr *E, 912 QualType ElementType, 913 llvm::Value *NewPtr, 914 llvm::Value *NumElements, 915 llvm::Value *AllocSizeWithoutCookie) { 916 const Expr *Init = E->getInitializer(); 917 if (E->isArray()) { 918 if (const CXXConstructExpr *CCE = dyn_cast_or_null<CXXConstructExpr>(Init)){ 919 CXXConstructorDecl *Ctor = CCE->getConstructor(); 920 if (Ctor->isTrivial()) { 921 // If new expression did not specify value-initialization, then there 922 // is no initialization. 923 if (!CCE->requiresZeroInitialization() || Ctor->getParent()->isEmpty()) 924 return; 925 926 if (CGF.CGM.getTypes().isZeroInitializable(ElementType)) { 927 // Optimization: since zero initialization will just set the memory 928 // to all zeroes, generate a single memset to do it in one shot. 929 EmitZeroMemSet(CGF, ElementType, NewPtr, AllocSizeWithoutCookie); 930 return; 931 } 932 } 933 934 CGF.EmitCXXAggrConstructorCall(Ctor, NumElements, NewPtr, 935 CCE->arg_begin(), CCE->arg_end(), 936 CCE->requiresZeroInitialization()); 937 return; 938 } else if (Init && isa<ImplicitValueInitExpr>(Init) && 939 CGF.CGM.getTypes().isZeroInitializable(ElementType)) { 940 // Optimization: since zero initialization will just set the memory 941 // to all zeroes, generate a single memset to do it in one shot. 942 EmitZeroMemSet(CGF, ElementType, NewPtr, AllocSizeWithoutCookie); 943 return; 944 } 945 CGF.EmitNewArrayInitializer(E, ElementType, NewPtr, NumElements); 946 return; 947 } 948 949 if (!Init) 950 return; 951 952 StoreAnyExprIntoOneUnit(CGF, Init, E->getAllocatedType(), NewPtr); 953} 954 955/// Emit a call to an operator new or operator delete function, as implicitly 956/// created by new-expressions and delete-expressions. 957static RValue EmitNewDeleteCall(CodeGenFunction &CGF, 958 const FunctionDecl *Callee, 959 const FunctionProtoType *CalleeType, 960 const CallArgList &Args) { 961 llvm::Instruction *CallOrInvoke; 962 llvm::Value *CalleeAddr = CGF.CGM.GetAddrOfFunction(Callee); 963 RValue RV = 964 CGF.EmitCall(CGF.CGM.getTypes().arrangeFreeFunctionCall(Args, CalleeType), 965 CalleeAddr, ReturnValueSlot(), Args, 966 Callee, &CallOrInvoke); 967 968 /// C++1y [expr.new]p10: 969 /// [In a new-expression,] an implementation is allowed to omit a call 970 /// to a replaceable global allocation function. 971 /// 972 /// We model such elidable calls with the 'builtin' attribute. 973 llvm::Function *Fn = dyn_cast<llvm::Function>(CalleeAddr); 974 if (Callee->isReplaceableGlobalAllocationFunction() && 975 Fn && Fn->hasFnAttribute(llvm::Attribute::NoBuiltin)) { 976 // FIXME: Add addAttribute to CallSite. 977 if (llvm::CallInst *CI = dyn_cast<llvm::CallInst>(CallOrInvoke)) 978 CI->addAttribute(llvm::AttributeSet::FunctionIndex, 979 llvm::Attribute::Builtin); 980 else if (llvm::InvokeInst *II = dyn_cast<llvm::InvokeInst>(CallOrInvoke)) 981 II->addAttribute(llvm::AttributeSet::FunctionIndex, 982 llvm::Attribute::Builtin); 983 else 984 llvm_unreachable("unexpected kind of call instruction"); 985 } 986 987 return RV; 988} 989 990namespace { 991 /// A cleanup to call the given 'operator delete' function upon 992 /// abnormal exit from a new expression. 993 class CallDeleteDuringNew : public EHScopeStack::Cleanup { 994 size_t NumPlacementArgs; 995 const FunctionDecl *OperatorDelete; 996 llvm::Value *Ptr; 997 llvm::Value *AllocSize; 998 999 RValue *getPlacementArgs() { return reinterpret_cast<RValue*>(this+1); } 1000 1001 public: 1002 static size_t getExtraSize(size_t NumPlacementArgs) { 1003 return NumPlacementArgs * sizeof(RValue); 1004 } 1005 1006 CallDeleteDuringNew(size_t NumPlacementArgs, 1007 const FunctionDecl *OperatorDelete, 1008 llvm::Value *Ptr, 1009 llvm::Value *AllocSize) 1010 : NumPlacementArgs(NumPlacementArgs), OperatorDelete(OperatorDelete), 1011 Ptr(Ptr), AllocSize(AllocSize) {} 1012 1013 void setPlacementArg(unsigned I, RValue Arg) { 1014 assert(I < NumPlacementArgs && "index out of range"); 1015 getPlacementArgs()[I] = Arg; 1016 } 1017 1018 void Emit(CodeGenFunction &CGF, Flags flags) override { 1019 const FunctionProtoType *FPT 1020 = OperatorDelete->getType()->getAs<FunctionProtoType>(); 1021 assert(FPT->getNumParams() == NumPlacementArgs + 1 || 1022 (FPT->getNumParams() == 2 && NumPlacementArgs == 0)); 1023 1024 CallArgList DeleteArgs; 1025 1026 // The first argument is always a void*. 1027 FunctionProtoType::param_type_iterator AI = FPT->param_type_begin(); 1028 DeleteArgs.add(RValue::get(Ptr), *AI++); 1029 1030 // A member 'operator delete' can take an extra 'size_t' argument. 1031 if (FPT->getNumParams() == NumPlacementArgs + 2) 1032 DeleteArgs.add(RValue::get(AllocSize), *AI++); 1033 1034 // Pass the rest of the arguments, which must match exactly. 1035 for (unsigned I = 0; I != NumPlacementArgs; ++I) 1036 DeleteArgs.add(getPlacementArgs()[I], *AI++); 1037 1038 // Call 'operator delete'. 1039 EmitNewDeleteCall(CGF, OperatorDelete, FPT, DeleteArgs); 1040 } 1041 }; 1042 1043 /// A cleanup to call the given 'operator delete' function upon 1044 /// abnormal exit from a new expression when the new expression is 1045 /// conditional. 1046 class CallDeleteDuringConditionalNew : public EHScopeStack::Cleanup { 1047 size_t NumPlacementArgs; 1048 const FunctionDecl *OperatorDelete; 1049 DominatingValue<RValue>::saved_type Ptr; 1050 DominatingValue<RValue>::saved_type AllocSize; 1051 1052 DominatingValue<RValue>::saved_type *getPlacementArgs() { 1053 return reinterpret_cast<DominatingValue<RValue>::saved_type*>(this+1); 1054 } 1055 1056 public: 1057 static size_t getExtraSize(size_t NumPlacementArgs) { 1058 return NumPlacementArgs * sizeof(DominatingValue<RValue>::saved_type); 1059 } 1060 1061 CallDeleteDuringConditionalNew(size_t NumPlacementArgs, 1062 const FunctionDecl *OperatorDelete, 1063 DominatingValue<RValue>::saved_type Ptr, 1064 DominatingValue<RValue>::saved_type AllocSize) 1065 : NumPlacementArgs(NumPlacementArgs), OperatorDelete(OperatorDelete), 1066 Ptr(Ptr), AllocSize(AllocSize) {} 1067 1068 void setPlacementArg(unsigned I, DominatingValue<RValue>::saved_type Arg) { 1069 assert(I < NumPlacementArgs && "index out of range"); 1070 getPlacementArgs()[I] = Arg; 1071 } 1072 1073 void Emit(CodeGenFunction &CGF, Flags flags) override { 1074 const FunctionProtoType *FPT 1075 = OperatorDelete->getType()->getAs<FunctionProtoType>(); 1076 assert(FPT->getNumParams() == NumPlacementArgs + 1 || 1077 (FPT->getNumParams() == 2 && NumPlacementArgs == 0)); 1078 1079 CallArgList DeleteArgs; 1080 1081 // The first argument is always a void*. 1082 FunctionProtoType::param_type_iterator AI = FPT->param_type_begin(); 1083 DeleteArgs.add(Ptr.restore(CGF), *AI++); 1084 1085 // A member 'operator delete' can take an extra 'size_t' argument. 1086 if (FPT->getNumParams() == NumPlacementArgs + 2) { 1087 RValue RV = AllocSize.restore(CGF); 1088 DeleteArgs.add(RV, *AI++); 1089 } 1090 1091 // Pass the rest of the arguments, which must match exactly. 1092 for (unsigned I = 0; I != NumPlacementArgs; ++I) { 1093 RValue RV = getPlacementArgs()[I].restore(CGF); 1094 DeleteArgs.add(RV, *AI++); 1095 } 1096 1097 // Call 'operator delete'. 1098 EmitNewDeleteCall(CGF, OperatorDelete, FPT, DeleteArgs); 1099 } 1100 }; 1101} 1102 1103/// Enter a cleanup to call 'operator delete' if the initializer in a 1104/// new-expression throws. 1105static void EnterNewDeleteCleanup(CodeGenFunction &CGF, 1106 const CXXNewExpr *E, 1107 llvm::Value *NewPtr, 1108 llvm::Value *AllocSize, 1109 const CallArgList &NewArgs) { 1110 // If we're not inside a conditional branch, then the cleanup will 1111 // dominate and we can do the easier (and more efficient) thing. 1112 if (!CGF.isInConditionalBranch()) { 1113 CallDeleteDuringNew *Cleanup = CGF.EHStack 1114 .pushCleanupWithExtra<CallDeleteDuringNew>(EHCleanup, 1115 E->getNumPlacementArgs(), 1116 E->getOperatorDelete(), 1117 NewPtr, AllocSize); 1118 for (unsigned I = 0, N = E->getNumPlacementArgs(); I != N; ++I) 1119 Cleanup->setPlacementArg(I, NewArgs[I+1].RV); 1120 1121 return; 1122 } 1123 1124 // Otherwise, we need to save all this stuff. 1125 DominatingValue<RValue>::saved_type SavedNewPtr = 1126 DominatingValue<RValue>::save(CGF, RValue::get(NewPtr)); 1127 DominatingValue<RValue>::saved_type SavedAllocSize = 1128 DominatingValue<RValue>::save(CGF, RValue::get(AllocSize)); 1129 1130 CallDeleteDuringConditionalNew *Cleanup = CGF.EHStack 1131 .pushCleanupWithExtra<CallDeleteDuringConditionalNew>(EHCleanup, 1132 E->getNumPlacementArgs(), 1133 E->getOperatorDelete(), 1134 SavedNewPtr, 1135 SavedAllocSize); 1136 for (unsigned I = 0, N = E->getNumPlacementArgs(); I != N; ++I) 1137 Cleanup->setPlacementArg(I, 1138 DominatingValue<RValue>::save(CGF, NewArgs[I+1].RV)); 1139 1140 CGF.initFullExprCleanup(); 1141} 1142 1143llvm::Value *CodeGenFunction::EmitCXXNewExpr(const CXXNewExpr *E) { 1144 // The element type being allocated. 1145 QualType allocType = getContext().getBaseElementType(E->getAllocatedType()); 1146 1147 // 1. Build a call to the allocation function. 1148 FunctionDecl *allocator = E->getOperatorNew(); 1149 const FunctionProtoType *allocatorType = 1150 allocator->getType()->castAs<FunctionProtoType>(); 1151 1152 CallArgList allocatorArgs; 1153 1154 // The allocation size is the first argument. 1155 QualType sizeType = getContext().getSizeType(); 1156 1157 // If there is a brace-initializer, cannot allocate fewer elements than inits. 1158 unsigned minElements = 0; 1159 if (E->isArray() && E->hasInitializer()) { 1160 if (const InitListExpr *ILE = dyn_cast<InitListExpr>(E->getInitializer())) 1161 minElements = ILE->getNumInits(); 1162 } 1163 1164 llvm::Value *numElements = nullptr; 1165 llvm::Value *allocSizeWithoutCookie = nullptr; 1166 llvm::Value *allocSize = 1167 EmitCXXNewAllocSize(*this, E, minElements, numElements, 1168 allocSizeWithoutCookie); 1169 1170 allocatorArgs.add(RValue::get(allocSize), sizeType); 1171 1172 // We start at 1 here because the first argument (the allocation size) 1173 // has already been emitted. 1174 EmitCallArgs(allocatorArgs, allocatorType->isVariadic(), 1175 allocatorType->param_type_begin() + 1, 1176 allocatorType->param_type_end(), E->placement_arg_begin(), 1177 E->placement_arg_end()); 1178 1179 // Emit the allocation call. If the allocator is a global placement 1180 // operator, just "inline" it directly. 1181 RValue RV; 1182 if (allocator->isReservedGlobalPlacementOperator()) { 1183 assert(allocatorArgs.size() == 2); 1184 RV = allocatorArgs[1].RV; 1185 // TODO: kill any unnecessary computations done for the size 1186 // argument. 1187 } else { 1188 RV = EmitNewDeleteCall(*this, allocator, allocatorType, allocatorArgs); 1189 } 1190 1191 // Emit a null check on the allocation result if the allocation 1192 // function is allowed to return null (because it has a non-throwing 1193 // exception spec; for this part, we inline 1194 // CXXNewExpr::shouldNullCheckAllocation()) and we have an 1195 // interesting initializer. 1196 bool nullCheck = allocatorType->isNothrow(getContext()) && 1197 (!allocType.isPODType(getContext()) || E->hasInitializer()); 1198 1199 llvm::BasicBlock *nullCheckBB = nullptr; 1200 llvm::BasicBlock *contBB = nullptr; 1201 1202 llvm::Value *allocation = RV.getScalarVal(); 1203 unsigned AS = allocation->getType()->getPointerAddressSpace(); 1204 1205 // The null-check means that the initializer is conditionally 1206 // evaluated. 1207 ConditionalEvaluation conditional(*this); 1208 1209 if (nullCheck) { 1210 conditional.begin(*this); 1211 1212 nullCheckBB = Builder.GetInsertBlock(); 1213 llvm::BasicBlock *notNullBB = createBasicBlock("new.notnull"); 1214 contBB = createBasicBlock("new.cont"); 1215 1216 llvm::Value *isNull = Builder.CreateIsNull(allocation, "new.isnull"); 1217 Builder.CreateCondBr(isNull, contBB, notNullBB); 1218 EmitBlock(notNullBB); 1219 } 1220 1221 // If there's an operator delete, enter a cleanup to call it if an 1222 // exception is thrown. 1223 EHScopeStack::stable_iterator operatorDeleteCleanup; 1224 llvm::Instruction *cleanupDominator = nullptr; 1225 if (E->getOperatorDelete() && 1226 !E->getOperatorDelete()->isReservedGlobalPlacementOperator()) { 1227 EnterNewDeleteCleanup(*this, E, allocation, allocSize, allocatorArgs); 1228 operatorDeleteCleanup = EHStack.stable_begin(); 1229 cleanupDominator = Builder.CreateUnreachable(); 1230 } 1231 1232 assert((allocSize == allocSizeWithoutCookie) == 1233 CalculateCookiePadding(*this, E).isZero()); 1234 if (allocSize != allocSizeWithoutCookie) { 1235 assert(E->isArray()); 1236 allocation = CGM.getCXXABI().InitializeArrayCookie(*this, allocation, 1237 numElements, 1238 E, allocType); 1239 } 1240 1241 llvm::Type *elementPtrTy 1242 = ConvertTypeForMem(allocType)->getPointerTo(AS); 1243 llvm::Value *result = Builder.CreateBitCast(allocation, elementPtrTy); 1244 1245 EmitNewInitializer(*this, E, allocType, result, numElements, 1246 allocSizeWithoutCookie); 1247 if (E->isArray()) { 1248 // NewPtr is a pointer to the base element type. If we're 1249 // allocating an array of arrays, we'll need to cast back to the 1250 // array pointer type. 1251 llvm::Type *resultType = ConvertTypeForMem(E->getType()); 1252 if (result->getType() != resultType) 1253 result = Builder.CreateBitCast(result, resultType); 1254 } 1255 1256 // Deactivate the 'operator delete' cleanup if we finished 1257 // initialization. 1258 if (operatorDeleteCleanup.isValid()) { 1259 DeactivateCleanupBlock(operatorDeleteCleanup, cleanupDominator); 1260 cleanupDominator->eraseFromParent(); 1261 } 1262 1263 if (nullCheck) { 1264 conditional.end(*this); 1265 1266 llvm::BasicBlock *notNullBB = Builder.GetInsertBlock(); 1267 EmitBlock(contBB); 1268 1269 llvm::PHINode *PHI = Builder.CreatePHI(result->getType(), 2); 1270 PHI->addIncoming(result, notNullBB); 1271 PHI->addIncoming(llvm::Constant::getNullValue(result->getType()), 1272 nullCheckBB); 1273 1274 result = PHI; 1275 } 1276 1277 return result; 1278} 1279 1280void CodeGenFunction::EmitDeleteCall(const FunctionDecl *DeleteFD, 1281 llvm::Value *Ptr, 1282 QualType DeleteTy) { 1283 assert(DeleteFD->getOverloadedOperator() == OO_Delete); 1284 1285 const FunctionProtoType *DeleteFTy = 1286 DeleteFD->getType()->getAs<FunctionProtoType>(); 1287 1288 CallArgList DeleteArgs; 1289 1290 // Check if we need to pass the size to the delete operator. 1291 llvm::Value *Size = nullptr; 1292 QualType SizeTy; 1293 if (DeleteFTy->getNumParams() == 2) { 1294 SizeTy = DeleteFTy->getParamType(1); 1295 CharUnits DeleteTypeSize = getContext().getTypeSizeInChars(DeleteTy); 1296 Size = llvm::ConstantInt::get(ConvertType(SizeTy), 1297 DeleteTypeSize.getQuantity()); 1298 } 1299 1300 QualType ArgTy = DeleteFTy->getParamType(0); 1301 llvm::Value *DeletePtr = Builder.CreateBitCast(Ptr, ConvertType(ArgTy)); 1302 DeleteArgs.add(RValue::get(DeletePtr), ArgTy); 1303 1304 if (Size) 1305 DeleteArgs.add(RValue::get(Size), SizeTy); 1306 1307 // Emit the call to delete. 1308 EmitNewDeleteCall(*this, DeleteFD, DeleteFTy, DeleteArgs); 1309} 1310 1311namespace { 1312 /// Calls the given 'operator delete' on a single object. 1313 struct CallObjectDelete : EHScopeStack::Cleanup { 1314 llvm::Value *Ptr; 1315 const FunctionDecl *OperatorDelete; 1316 QualType ElementType; 1317 1318 CallObjectDelete(llvm::Value *Ptr, 1319 const FunctionDecl *OperatorDelete, 1320 QualType ElementType) 1321 : Ptr(Ptr), OperatorDelete(OperatorDelete), ElementType(ElementType) {} 1322 1323 void Emit(CodeGenFunction &CGF, Flags flags) override { 1324 CGF.EmitDeleteCall(OperatorDelete, Ptr, ElementType); 1325 } 1326 }; 1327} 1328 1329/// Emit the code for deleting a single object. 1330static void EmitObjectDelete(CodeGenFunction &CGF, 1331 const FunctionDecl *OperatorDelete, 1332 llvm::Value *Ptr, 1333 QualType ElementType, 1334 bool UseGlobalDelete) { 1335 // Find the destructor for the type, if applicable. If the 1336 // destructor is virtual, we'll just emit the vcall and return. 1337 const CXXDestructorDecl *Dtor = nullptr; 1338 if (const RecordType *RT = ElementType->getAs<RecordType>()) { 1339 CXXRecordDecl *RD = cast<CXXRecordDecl>(RT->getDecl()); 1340 if (RD->hasDefinition() && !RD->hasTrivialDestructor()) { 1341 Dtor = RD->getDestructor(); 1342 1343 if (Dtor->isVirtual()) { 1344 if (UseGlobalDelete) { 1345 // If we're supposed to call the global delete, make sure we do so 1346 // even if the destructor throws. 1347 1348 // Derive the complete-object pointer, which is what we need 1349 // to pass to the deallocation function. 1350 llvm::Value *completePtr = 1351 CGF.CGM.getCXXABI().adjustToCompleteObject(CGF, Ptr, ElementType); 1352 1353 CGF.EHStack.pushCleanup<CallObjectDelete>(NormalAndEHCleanup, 1354 completePtr, OperatorDelete, 1355 ElementType); 1356 } 1357 1358 // FIXME: Provide a source location here. 1359 CXXDtorType DtorType = UseGlobalDelete ? Dtor_Complete : Dtor_Deleting; 1360 CGF.CGM.getCXXABI().EmitVirtualDestructorCall(CGF, Dtor, DtorType, 1361 SourceLocation(), Ptr); 1362 1363 if (UseGlobalDelete) { 1364 CGF.PopCleanupBlock(); 1365 } 1366 1367 return; 1368 } 1369 } 1370 } 1371 1372 // Make sure that we call delete even if the dtor throws. 1373 // This doesn't have to a conditional cleanup because we're going 1374 // to pop it off in a second. 1375 CGF.EHStack.pushCleanup<CallObjectDelete>(NormalAndEHCleanup, 1376 Ptr, OperatorDelete, ElementType); 1377 1378 if (Dtor) 1379 CGF.EmitCXXDestructorCall(Dtor, Dtor_Complete, 1380 /*ForVirtualBase=*/false, 1381 /*Delegating=*/false, 1382 Ptr); 1383 else if (CGF.getLangOpts().ObjCAutoRefCount && 1384 ElementType->isObjCLifetimeType()) { 1385 switch (ElementType.getObjCLifetime()) { 1386 case Qualifiers::OCL_None: 1387 case Qualifiers::OCL_ExplicitNone: 1388 case Qualifiers::OCL_Autoreleasing: 1389 break; 1390 1391 case Qualifiers::OCL_Strong: { 1392 // Load the pointer value. 1393 llvm::Value *PtrValue = CGF.Builder.CreateLoad(Ptr, 1394 ElementType.isVolatileQualified()); 1395 1396 CGF.EmitARCRelease(PtrValue, ARCPreciseLifetime); 1397 break; 1398 } 1399 1400 case Qualifiers::OCL_Weak: 1401 CGF.EmitARCDestroyWeak(Ptr); 1402 break; 1403 } 1404 } 1405 1406 CGF.PopCleanupBlock(); 1407} 1408 1409namespace { 1410 /// Calls the given 'operator delete' on an array of objects. 1411 struct CallArrayDelete : EHScopeStack::Cleanup { 1412 llvm::Value *Ptr; 1413 const FunctionDecl *OperatorDelete; 1414 llvm::Value *NumElements; 1415 QualType ElementType; 1416 CharUnits CookieSize; 1417 1418 CallArrayDelete(llvm::Value *Ptr, 1419 const FunctionDecl *OperatorDelete, 1420 llvm::Value *NumElements, 1421 QualType ElementType, 1422 CharUnits CookieSize) 1423 : Ptr(Ptr), OperatorDelete(OperatorDelete), NumElements(NumElements), 1424 ElementType(ElementType), CookieSize(CookieSize) {} 1425 1426 void Emit(CodeGenFunction &CGF, Flags flags) override { 1427 const FunctionProtoType *DeleteFTy = 1428 OperatorDelete->getType()->getAs<FunctionProtoType>(); 1429 assert(DeleteFTy->getNumParams() == 1 || DeleteFTy->getNumParams() == 2); 1430 1431 CallArgList Args; 1432 1433 // Pass the pointer as the first argument. 1434 QualType VoidPtrTy = DeleteFTy->getParamType(0); 1435 llvm::Value *DeletePtr 1436 = CGF.Builder.CreateBitCast(Ptr, CGF.ConvertType(VoidPtrTy)); 1437 Args.add(RValue::get(DeletePtr), VoidPtrTy); 1438 1439 // Pass the original requested size as the second argument. 1440 if (DeleteFTy->getNumParams() == 2) { 1441 QualType size_t = DeleteFTy->getParamType(1); 1442 llvm::IntegerType *SizeTy 1443 = cast<llvm::IntegerType>(CGF.ConvertType(size_t)); 1444 1445 CharUnits ElementTypeSize = 1446 CGF.CGM.getContext().getTypeSizeInChars(ElementType); 1447 1448 // The size of an element, multiplied by the number of elements. 1449 llvm::Value *Size 1450 = llvm::ConstantInt::get(SizeTy, ElementTypeSize.getQuantity()); 1451 Size = CGF.Builder.CreateMul(Size, NumElements); 1452 1453 // Plus the size of the cookie if applicable. 1454 if (!CookieSize.isZero()) { 1455 llvm::Value *CookieSizeV 1456 = llvm::ConstantInt::get(SizeTy, CookieSize.getQuantity()); 1457 Size = CGF.Builder.CreateAdd(Size, CookieSizeV); 1458 } 1459 1460 Args.add(RValue::get(Size), size_t); 1461 } 1462 1463 // Emit the call to delete. 1464 EmitNewDeleteCall(CGF, OperatorDelete, DeleteFTy, Args); 1465 } 1466 }; 1467} 1468 1469/// Emit the code for deleting an array of objects. 1470static void EmitArrayDelete(CodeGenFunction &CGF, 1471 const CXXDeleteExpr *E, 1472 llvm::Value *deletedPtr, 1473 QualType elementType) { 1474 llvm::Value *numElements = nullptr; 1475 llvm::Value *allocatedPtr = nullptr; 1476 CharUnits cookieSize; 1477 CGF.CGM.getCXXABI().ReadArrayCookie(CGF, deletedPtr, E, elementType, 1478 numElements, allocatedPtr, cookieSize); 1479 1480 assert(allocatedPtr && "ReadArrayCookie didn't set allocated pointer"); 1481 1482 // Make sure that we call delete even if one of the dtors throws. 1483 const FunctionDecl *operatorDelete = E->getOperatorDelete(); 1484 CGF.EHStack.pushCleanup<CallArrayDelete>(NormalAndEHCleanup, 1485 allocatedPtr, operatorDelete, 1486 numElements, elementType, 1487 cookieSize); 1488 1489 // Destroy the elements. 1490 if (QualType::DestructionKind dtorKind = elementType.isDestructedType()) { 1491 assert(numElements && "no element count for a type with a destructor!"); 1492 1493 llvm::Value *arrayEnd = 1494 CGF.Builder.CreateInBoundsGEP(deletedPtr, numElements, "delete.end"); 1495 1496 // Note that it is legal to allocate a zero-length array, and we 1497 // can never fold the check away because the length should always 1498 // come from a cookie. 1499 CGF.emitArrayDestroy(deletedPtr, arrayEnd, elementType, 1500 CGF.getDestroyer(dtorKind), 1501 /*checkZeroLength*/ true, 1502 CGF.needsEHCleanup(dtorKind)); 1503 } 1504 1505 // Pop the cleanup block. 1506 CGF.PopCleanupBlock(); 1507} 1508 1509void CodeGenFunction::EmitCXXDeleteExpr(const CXXDeleteExpr *E) { 1510 const Expr *Arg = E->getArgument(); 1511 llvm::Value *Ptr = EmitScalarExpr(Arg); 1512 1513 // Null check the pointer. 1514 llvm::BasicBlock *DeleteNotNull = createBasicBlock("delete.notnull"); 1515 llvm::BasicBlock *DeleteEnd = createBasicBlock("delete.end"); 1516 1517 llvm::Value *IsNull = Builder.CreateIsNull(Ptr, "isnull"); 1518 1519 Builder.CreateCondBr(IsNull, DeleteEnd, DeleteNotNull); 1520 EmitBlock(DeleteNotNull); 1521 1522 // We might be deleting a pointer to array. If so, GEP down to the 1523 // first non-array element. 1524 // (this assumes that A(*)[3][7] is converted to [3 x [7 x %A]]*) 1525 QualType DeleteTy = Arg->getType()->getAs<PointerType>()->getPointeeType(); 1526 if (DeleteTy->isConstantArrayType()) { 1527 llvm::Value *Zero = Builder.getInt32(0); 1528 SmallVector<llvm::Value*,8> GEP; 1529 1530 GEP.push_back(Zero); // point at the outermost array 1531 1532 // For each layer of array type we're pointing at: 1533 while (const ConstantArrayType *Arr 1534 = getContext().getAsConstantArrayType(DeleteTy)) { 1535 // 1. Unpeel the array type. 1536 DeleteTy = Arr->getElementType(); 1537 1538 // 2. GEP to the first element of the array. 1539 GEP.push_back(Zero); 1540 } 1541 1542 Ptr = Builder.CreateInBoundsGEP(Ptr, GEP, "del.first"); 1543 } 1544 1545 assert(ConvertTypeForMem(DeleteTy) == 1546 cast<llvm::PointerType>(Ptr->getType())->getElementType()); 1547 1548 if (E->isArrayForm()) { 1549 EmitArrayDelete(*this, E, Ptr, DeleteTy); 1550 } else { 1551 EmitObjectDelete(*this, E->getOperatorDelete(), Ptr, DeleteTy, 1552 E->isGlobalDelete()); 1553 } 1554 1555 EmitBlock(DeleteEnd); 1556} 1557 1558static llvm::Constant *getBadTypeidFn(CodeGenFunction &CGF) { 1559 // void __cxa_bad_typeid(); 1560 llvm::FunctionType *FTy = llvm::FunctionType::get(CGF.VoidTy, false); 1561 1562 return CGF.CGM.CreateRuntimeFunction(FTy, "__cxa_bad_typeid"); 1563} 1564 1565static void EmitBadTypeidCall(CodeGenFunction &CGF) { 1566 llvm::Value *Fn = getBadTypeidFn(CGF); 1567 CGF.EmitRuntimeCallOrInvoke(Fn).setDoesNotReturn(); 1568 CGF.Builder.CreateUnreachable(); 1569} 1570 1571static llvm::Value *EmitTypeidFromVTable(CodeGenFunction &CGF, 1572 const Expr *E, 1573 llvm::Type *StdTypeInfoPtrTy) { 1574 // Get the vtable pointer. 1575 llvm::Value *ThisPtr = CGF.EmitLValue(E).getAddress(); 1576 1577 // C++ [expr.typeid]p2: 1578 // If the glvalue expression is obtained by applying the unary * operator to 1579 // a pointer and the pointer is a null pointer value, the typeid expression 1580 // throws the std::bad_typeid exception. 1581 if (const UnaryOperator *UO = dyn_cast<UnaryOperator>(E->IgnoreParens())) { 1582 if (UO->getOpcode() == UO_Deref) { 1583 llvm::BasicBlock *BadTypeidBlock = 1584 CGF.createBasicBlock("typeid.bad_typeid"); 1585 llvm::BasicBlock *EndBlock = 1586 CGF.createBasicBlock("typeid.end"); 1587 1588 llvm::Value *IsNull = CGF.Builder.CreateIsNull(ThisPtr); 1589 CGF.Builder.CreateCondBr(IsNull, BadTypeidBlock, EndBlock); 1590 1591 CGF.EmitBlock(BadTypeidBlock); 1592 EmitBadTypeidCall(CGF); 1593 CGF.EmitBlock(EndBlock); 1594 } 1595 } 1596 1597 llvm::Value *Value = CGF.GetVTablePtr(ThisPtr, 1598 StdTypeInfoPtrTy->getPointerTo()); 1599 1600 // Load the type info. 1601 Value = CGF.Builder.CreateConstInBoundsGEP1_64(Value, -1ULL); 1602 return CGF.Builder.CreateLoad(Value); 1603} 1604 1605llvm::Value *CodeGenFunction::EmitCXXTypeidExpr(const CXXTypeidExpr *E) { 1606 llvm::Type *StdTypeInfoPtrTy = 1607 ConvertType(E->getType())->getPointerTo(); 1608 1609 if (E->isTypeOperand()) { 1610 llvm::Constant *TypeInfo = 1611 CGM.GetAddrOfRTTIDescriptor(E->getTypeOperand(getContext())); 1612 return Builder.CreateBitCast(TypeInfo, StdTypeInfoPtrTy); 1613 } 1614 1615 // C++ [expr.typeid]p2: 1616 // When typeid is applied to a glvalue expression whose type is a 1617 // polymorphic class type, the result refers to a std::type_info object 1618 // representing the type of the most derived object (that is, the dynamic 1619 // type) to which the glvalue refers. 1620 if (E->isPotentiallyEvaluated()) 1621 return EmitTypeidFromVTable(*this, E->getExprOperand(), 1622 StdTypeInfoPtrTy); 1623 1624 QualType OperandTy = E->getExprOperand()->getType(); 1625 return Builder.CreateBitCast(CGM.GetAddrOfRTTIDescriptor(OperandTy), 1626 StdTypeInfoPtrTy); 1627} 1628 1629static llvm::Constant *getDynamicCastFn(CodeGenFunction &CGF) { 1630 // void *__dynamic_cast(const void *sub, 1631 // const abi::__class_type_info *src, 1632 // const abi::__class_type_info *dst, 1633 // std::ptrdiff_t src2dst_offset); 1634 1635 llvm::Type *Int8PtrTy = CGF.Int8PtrTy; 1636 llvm::Type *PtrDiffTy = 1637 CGF.ConvertType(CGF.getContext().getPointerDiffType()); 1638 1639 llvm::Type *Args[4] = { Int8PtrTy, Int8PtrTy, Int8PtrTy, PtrDiffTy }; 1640 1641 llvm::FunctionType *FTy = llvm::FunctionType::get(Int8PtrTy, Args, false); 1642 1643 // Mark the function as nounwind readonly. 1644 llvm::Attribute::AttrKind FuncAttrs[] = { llvm::Attribute::NoUnwind, 1645 llvm::Attribute::ReadOnly }; 1646 llvm::AttributeSet Attrs = llvm::AttributeSet::get( 1647 CGF.getLLVMContext(), llvm::AttributeSet::FunctionIndex, FuncAttrs); 1648 1649 return CGF.CGM.CreateRuntimeFunction(FTy, "__dynamic_cast", Attrs); 1650} 1651 1652static llvm::Constant *getBadCastFn(CodeGenFunction &CGF) { 1653 // void __cxa_bad_cast(); 1654 llvm::FunctionType *FTy = llvm::FunctionType::get(CGF.VoidTy, false); 1655 return CGF.CGM.CreateRuntimeFunction(FTy, "__cxa_bad_cast"); 1656} 1657 1658static void EmitBadCastCall(CodeGenFunction &CGF) { 1659 llvm::Value *Fn = getBadCastFn(CGF); 1660 CGF.EmitRuntimeCallOrInvoke(Fn).setDoesNotReturn(); 1661 CGF.Builder.CreateUnreachable(); 1662} 1663 1664/// \brief Compute the src2dst_offset hint as described in the 1665/// Itanium C++ ABI [2.9.7] 1666static CharUnits computeOffsetHint(ASTContext &Context, 1667 const CXXRecordDecl *Src, 1668 const CXXRecordDecl *Dst) { 1669 CXXBasePaths Paths(/*FindAmbiguities=*/true, /*RecordPaths=*/true, 1670 /*DetectVirtual=*/false); 1671 1672 // If Dst is not derived from Src we can skip the whole computation below and 1673 // return that Src is not a public base of Dst. Record all inheritance paths. 1674 if (!Dst->isDerivedFrom(Src, Paths)) 1675 return CharUnits::fromQuantity(-2ULL); 1676 1677 unsigned NumPublicPaths = 0; 1678 CharUnits Offset; 1679 1680 // Now walk all possible inheritance paths. 1681 for (CXXBasePaths::paths_iterator I = Paths.begin(), E = Paths.end(); 1682 I != E; ++I) { 1683 if (I->Access != AS_public) // Ignore non-public inheritance. 1684 continue; 1685 1686 ++NumPublicPaths; 1687 1688 for (CXXBasePath::iterator J = I->begin(), JE = I->end(); J != JE; ++J) { 1689 // If the path contains a virtual base class we can't give any hint. 1690 // -1: no hint. 1691 if (J->Base->isVirtual()) 1692 return CharUnits::fromQuantity(-1ULL); 1693 1694 if (NumPublicPaths > 1) // Won't use offsets, skip computation. 1695 continue; 1696 1697 // Accumulate the base class offsets. 1698 const ASTRecordLayout &L = Context.getASTRecordLayout(J->Class); 1699 Offset += L.getBaseClassOffset(J->Base->getType()->getAsCXXRecordDecl()); 1700 } 1701 } 1702 1703 // -2: Src is not a public base of Dst. 1704 if (NumPublicPaths == 0) 1705 return CharUnits::fromQuantity(-2ULL); 1706 1707 // -3: Src is a multiple public base type but never a virtual base type. 1708 if (NumPublicPaths > 1) 1709 return CharUnits::fromQuantity(-3ULL); 1710 1711 // Otherwise, the Src type is a unique public nonvirtual base type of Dst. 1712 // Return the offset of Src from the origin of Dst. 1713 return Offset; 1714} 1715 1716static llvm::Value * 1717EmitDynamicCastCall(CodeGenFunction &CGF, llvm::Value *Value, 1718 QualType SrcTy, QualType DestTy, 1719 llvm::BasicBlock *CastEnd) { 1720 llvm::Type *PtrDiffLTy = 1721 CGF.ConvertType(CGF.getContext().getPointerDiffType()); 1722 llvm::Type *DestLTy = CGF.ConvertType(DestTy); 1723 1724 if (const PointerType *PTy = DestTy->getAs<PointerType>()) { 1725 if (PTy->getPointeeType()->isVoidType()) { 1726 // C++ [expr.dynamic.cast]p7: 1727 // If T is "pointer to cv void," then the result is a pointer to the 1728 // most derived object pointed to by v. 1729 1730 // Get the vtable pointer. 1731 llvm::Value *VTable = CGF.GetVTablePtr(Value, PtrDiffLTy->getPointerTo()); 1732 1733 // Get the offset-to-top from the vtable. 1734 llvm::Value *OffsetToTop = 1735 CGF.Builder.CreateConstInBoundsGEP1_64(VTable, -2ULL); 1736 OffsetToTop = CGF.Builder.CreateLoad(OffsetToTop, "offset.to.top"); 1737 1738 // Finally, add the offset to the pointer. 1739 Value = CGF.EmitCastToVoidPtr(Value); 1740 Value = CGF.Builder.CreateInBoundsGEP(Value, OffsetToTop); 1741 1742 return CGF.Builder.CreateBitCast(Value, DestLTy); 1743 } 1744 } 1745 1746 QualType SrcRecordTy; 1747 QualType DestRecordTy; 1748 1749 if (const PointerType *DestPTy = DestTy->getAs<PointerType>()) { 1750 SrcRecordTy = SrcTy->castAs<PointerType>()->getPointeeType(); 1751 DestRecordTy = DestPTy->getPointeeType(); 1752 } else { 1753 SrcRecordTy = SrcTy; 1754 DestRecordTy = DestTy->castAs<ReferenceType>()->getPointeeType(); 1755 } 1756 1757 assert(SrcRecordTy->isRecordType() && "source type must be a record type!"); 1758 assert(DestRecordTy->isRecordType() && "dest type must be a record type!"); 1759 1760 llvm::Value *SrcRTTI = 1761 CGF.CGM.GetAddrOfRTTIDescriptor(SrcRecordTy.getUnqualifiedType()); 1762 llvm::Value *DestRTTI = 1763 CGF.CGM.GetAddrOfRTTIDescriptor(DestRecordTy.getUnqualifiedType()); 1764 1765 // Compute the offset hint. 1766 const CXXRecordDecl *SrcDecl = SrcRecordTy->getAsCXXRecordDecl(); 1767 const CXXRecordDecl *DestDecl = DestRecordTy->getAsCXXRecordDecl(); 1768 llvm::Value *OffsetHint = 1769 llvm::ConstantInt::get(PtrDiffLTy, 1770 computeOffsetHint(CGF.getContext(), SrcDecl, 1771 DestDecl).getQuantity()); 1772 1773 // Emit the call to __dynamic_cast. 1774 Value = CGF.EmitCastToVoidPtr(Value); 1775 1776 llvm::Value *args[] = { Value, SrcRTTI, DestRTTI, OffsetHint }; 1777 Value = CGF.EmitNounwindRuntimeCall(getDynamicCastFn(CGF), args); 1778 Value = CGF.Builder.CreateBitCast(Value, DestLTy); 1779 1780 /// C++ [expr.dynamic.cast]p9: 1781 /// A failed cast to reference type throws std::bad_cast 1782 if (DestTy->isReferenceType()) { 1783 llvm::BasicBlock *BadCastBlock = 1784 CGF.createBasicBlock("dynamic_cast.bad_cast"); 1785 1786 llvm::Value *IsNull = CGF.Builder.CreateIsNull(Value); 1787 CGF.Builder.CreateCondBr(IsNull, BadCastBlock, CastEnd); 1788 1789 CGF.EmitBlock(BadCastBlock); 1790 EmitBadCastCall(CGF); 1791 } 1792 1793 return Value; 1794} 1795 1796static llvm::Value *EmitDynamicCastToNull(CodeGenFunction &CGF, 1797 QualType DestTy) { 1798 llvm::Type *DestLTy = CGF.ConvertType(DestTy); 1799 if (DestTy->isPointerType()) 1800 return llvm::Constant::getNullValue(DestLTy); 1801 1802 /// C++ [expr.dynamic.cast]p9: 1803 /// A failed cast to reference type throws std::bad_cast 1804 EmitBadCastCall(CGF); 1805 1806 CGF.EmitBlock(CGF.createBasicBlock("dynamic_cast.end")); 1807 return llvm::UndefValue::get(DestLTy); 1808} 1809 1810llvm::Value *CodeGenFunction::EmitDynamicCast(llvm::Value *Value, 1811 const CXXDynamicCastExpr *DCE) { 1812 QualType DestTy = DCE->getTypeAsWritten(); 1813 1814 if (DCE->isAlwaysNull()) 1815 return EmitDynamicCastToNull(*this, DestTy); 1816 1817 QualType SrcTy = DCE->getSubExpr()->getType(); 1818 1819 // C++ [expr.dynamic.cast]p4: 1820 // If the value of v is a null pointer value in the pointer case, the result 1821 // is the null pointer value of type T. 1822 bool ShouldNullCheckSrcValue = SrcTy->isPointerType(); 1823 1824 llvm::BasicBlock *CastNull = nullptr; 1825 llvm::BasicBlock *CastNotNull = nullptr; 1826 llvm::BasicBlock *CastEnd = createBasicBlock("dynamic_cast.end"); 1827 1828 if (ShouldNullCheckSrcValue) { 1829 CastNull = createBasicBlock("dynamic_cast.null"); 1830 CastNotNull = createBasicBlock("dynamic_cast.notnull"); 1831 1832 llvm::Value *IsNull = Builder.CreateIsNull(Value); 1833 Builder.CreateCondBr(IsNull, CastNull, CastNotNull); 1834 EmitBlock(CastNotNull); 1835 } 1836 1837 Value = EmitDynamicCastCall(*this, Value, SrcTy, DestTy, CastEnd); 1838 1839 if (ShouldNullCheckSrcValue) { 1840 EmitBranch(CastEnd); 1841 1842 EmitBlock(CastNull); 1843 EmitBranch(CastEnd); 1844 } 1845 1846 EmitBlock(CastEnd); 1847 1848 if (ShouldNullCheckSrcValue) { 1849 llvm::PHINode *PHI = Builder.CreatePHI(Value->getType(), 2); 1850 PHI->addIncoming(Value, CastNotNull); 1851 PHI->addIncoming(llvm::Constant::getNullValue(Value->getType()), CastNull); 1852 1853 Value = PHI; 1854 } 1855 1856 return Value; 1857} 1858 1859void CodeGenFunction::EmitLambdaExpr(const LambdaExpr *E, AggValueSlot Slot) { 1860 RunCleanupsScope Scope(*this); 1861 LValue SlotLV = MakeAddrLValue(Slot.getAddr(), E->getType(), 1862 Slot.getAlignment()); 1863 1864 CXXRecordDecl::field_iterator CurField = E->getLambdaClass()->field_begin(); 1865 for (LambdaExpr::capture_init_iterator i = E->capture_init_begin(), 1866 e = E->capture_init_end(); 1867 i != e; ++i, ++CurField) { 1868 // Emit initialization 1869 1870 LValue LV = EmitLValueForFieldInitialization(SlotLV, *CurField); 1871 ArrayRef<VarDecl *> ArrayIndexes; 1872 if (CurField->getType()->isArrayType()) 1873 ArrayIndexes = E->getCaptureInitIndexVars(i); 1874 EmitInitializerForField(*CurField, LV, *i, ArrayIndexes); 1875 } 1876} 1877