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 "clang/Frontend/CodeGenOptions.h" 15 #include "CodeGenFunction.h" 16 #include "CGCUDARuntime.h" 17 #include "CGCXXABI.h" 18 #include "CGObjCRuntime.h" 19 #include "CGDebugInfo.h" 20 #include "llvm/Intrinsics.h" 21 #include "llvm/Support/CallSite.h" 22 23 using namespace clang; 24 using namespace CodeGen; 25 26 RValue CodeGenFunction::EmitCXXMemberCall(const CXXMethodDecl *MD, 27 llvm::Value *Callee, 28 ReturnValueSlot ReturnValue, 29 llvm::Value *This, 30 llvm::Value *VTT, 31 CallExpr::const_arg_iterator ArgBeg, 32 CallExpr::const_arg_iterator ArgEnd) { 33 assert(MD->isInstance() && 34 "Trying to emit a member call expr on a static method!"); 35 36 CallArgList Args; 37 38 // Push the this ptr. 39 Args.add(RValue::get(This), MD->getThisType(getContext())); 40 41 // If there is a VTT parameter, emit it. 42 if (VTT) { 43 QualType T = getContext().getPointerType(getContext().VoidPtrTy); 44 Args.add(RValue::get(VTT), T); 45 } 46 47 const FunctionProtoType *FPT = MD->getType()->castAs<FunctionProtoType>(); 48 RequiredArgs required = RequiredArgs::forPrototypePlus(FPT, Args.size()); 49 50 // And the rest of the call args. 51 EmitCallArgs(Args, FPT, ArgBeg, ArgEnd); 52 53 return EmitCall(CGM.getTypes().arrangeFunctionCall(FPT->getResultType(), Args, 54 FPT->getExtInfo(), 55 required), 56 Callee, ReturnValue, Args, MD); 57 } 58 59 static const CXXRecordDecl *getMostDerivedClassDecl(const Expr *Base) { 60 const Expr *E = Base; 61 62 while (true) { 63 E = E->IgnoreParens(); 64 if (const CastExpr *CE = dyn_cast<CastExpr>(E)) { 65 if (CE->getCastKind() == CK_DerivedToBase || 66 CE->getCastKind() == CK_UncheckedDerivedToBase || 67 CE->getCastKind() == CK_NoOp) { 68 E = CE->getSubExpr(); 69 continue; 70 } 71 } 72 73 break; 74 } 75 76 QualType DerivedType = E->getType(); 77 if (const PointerType *PTy = DerivedType->getAs<PointerType>()) 78 DerivedType = PTy->getPointeeType(); 79 80 return cast<CXXRecordDecl>(DerivedType->castAs<RecordType>()->getDecl()); 81 } 82 83 // FIXME: Ideally Expr::IgnoreParenNoopCasts should do this, but it doesn't do 84 // quite what we want. 85 static const Expr *skipNoOpCastsAndParens(const Expr *E) { 86 while (true) { 87 if (const ParenExpr *PE = dyn_cast<ParenExpr>(E)) { 88 E = PE->getSubExpr(); 89 continue; 90 } 91 92 if (const CastExpr *CE = dyn_cast<CastExpr>(E)) { 93 if (CE->getCastKind() == CK_NoOp) { 94 E = CE->getSubExpr(); 95 continue; 96 } 97 } 98 if (const UnaryOperator *UO = dyn_cast<UnaryOperator>(E)) { 99 if (UO->getOpcode() == UO_Extension) { 100 E = UO->getSubExpr(); 101 continue; 102 } 103 } 104 return E; 105 } 106 } 107 108 /// canDevirtualizeMemberFunctionCalls - Checks whether virtual calls on given 109 /// expr can be devirtualized. 110 static bool canDevirtualizeMemberFunctionCalls(ASTContext &Context, 111 const Expr *Base, 112 const CXXMethodDecl *MD) { 113 114 // When building with -fapple-kext, all calls must go through the vtable since 115 // the kernel linker can do runtime patching of vtables. 116 if (Context.getLangOpts().AppleKext) 117 return false; 118 119 // If the most derived class is marked final, we know that no subclass can 120 // override this member function and so we can devirtualize it. For example: 121 // 122 // struct A { virtual void f(); } 123 // struct B final : A { }; 124 // 125 // void f(B *b) { 126 // b->f(); 127 // } 128 // 129 const CXXRecordDecl *MostDerivedClassDecl = getMostDerivedClassDecl(Base); 130 if (MostDerivedClassDecl->hasAttr<FinalAttr>()) 131 return true; 132 133 // If the member function is marked 'final', we know that it can't be 134 // overridden and can therefore devirtualize it. 135 if (MD->hasAttr<FinalAttr>()) 136 return true; 137 138 // Similarly, if the class itself is marked 'final' it can't be overridden 139 // and we can therefore devirtualize the member function call. 140 if (MD->getParent()->hasAttr<FinalAttr>()) 141 return true; 142 143 Base = skipNoOpCastsAndParens(Base); 144 if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(Base)) { 145 if (const VarDecl *VD = dyn_cast<VarDecl>(DRE->getDecl())) { 146 // This is a record decl. We know the type and can devirtualize it. 147 return VD->getType()->isRecordType(); 148 } 149 150 return false; 151 } 152 153 // We can always devirtualize calls on temporary object expressions. 154 if (isa<CXXConstructExpr>(Base)) 155 return true; 156 157 // And calls on bound temporaries. 158 if (isa<CXXBindTemporaryExpr>(Base)) 159 return true; 160 161 // Check if this is a call expr that returns a record type. 162 if (const CallExpr *CE = dyn_cast<CallExpr>(Base)) 163 return CE->getCallReturnType()->isRecordType(); 164 165 // We can't devirtualize the call. 166 return false; 167 } 168 169 // Note: This function also emit constructor calls to support a MSVC 170 // extensions allowing explicit constructor function call. 171 RValue CodeGenFunction::EmitCXXMemberCallExpr(const CXXMemberCallExpr *CE, 172 ReturnValueSlot ReturnValue) { 173 const Expr *callee = CE->getCallee()->IgnoreParens(); 174 175 if (isa<BinaryOperator>(callee)) 176 return EmitCXXMemberPointerCallExpr(CE, ReturnValue); 177 178 const MemberExpr *ME = cast<MemberExpr>(callee); 179 const CXXMethodDecl *MD = cast<CXXMethodDecl>(ME->getMemberDecl()); 180 181 CGDebugInfo *DI = getDebugInfo(); 182 if (DI && CGM.getCodeGenOpts().LimitDebugInfo 183 && !isa<CallExpr>(ME->getBase())) { 184 QualType PQTy = ME->getBase()->IgnoreParenImpCasts()->getType(); 185 if (const PointerType * PTy = dyn_cast<PointerType>(PQTy)) { 186 DI->getOrCreateRecordType(PTy->getPointeeType(), 187 MD->getParent()->getLocation()); 188 } 189 } 190 191 if (MD->isStatic()) { 192 // The method is static, emit it as we would a regular call. 193 llvm::Value *Callee = CGM.GetAddrOfFunction(MD); 194 return EmitCall(getContext().getPointerType(MD->getType()), Callee, 195 ReturnValue, CE->arg_begin(), CE->arg_end()); 196 } 197 198 // Compute the object pointer. 199 llvm::Value *This; 200 if (ME->isArrow()) 201 This = EmitScalarExpr(ME->getBase()); 202 else 203 This = EmitLValue(ME->getBase()).getAddress(); 204 205 if (MD->isTrivial()) { 206 if (isa<CXXDestructorDecl>(MD)) return RValue::get(0); 207 if (isa<CXXConstructorDecl>(MD) && 208 cast<CXXConstructorDecl>(MD)->isDefaultConstructor()) 209 return RValue::get(0); 210 211 if (MD->isCopyAssignmentOperator() || MD->isMoveAssignmentOperator()) { 212 // We don't like to generate the trivial copy/move assignment operator 213 // when it isn't necessary; just produce the proper effect here. 214 llvm::Value *RHS = EmitLValue(*CE->arg_begin()).getAddress(); 215 EmitAggregateCopy(This, RHS, CE->getType()); 216 return RValue::get(This); 217 } 218 219 if (isa<CXXConstructorDecl>(MD) && 220 cast<CXXConstructorDecl>(MD)->isCopyOrMoveConstructor()) { 221 // Trivial move and copy ctor are the same. 222 llvm::Value *RHS = EmitLValue(*CE->arg_begin()).getAddress(); 223 EmitSynthesizedCXXCopyCtorCall(cast<CXXConstructorDecl>(MD), This, RHS, 224 CE->arg_begin(), CE->arg_end()); 225 return RValue::get(This); 226 } 227 llvm_unreachable("unknown trivial member function"); 228 } 229 230 // Compute the function type we're calling. 231 const CGFunctionInfo *FInfo = 0; 232 if (isa<CXXDestructorDecl>(MD)) 233 FInfo = &CGM.getTypes().arrangeCXXDestructor(cast<CXXDestructorDecl>(MD), 234 Dtor_Complete); 235 else if (isa<CXXConstructorDecl>(MD)) 236 FInfo = &CGM.getTypes().arrangeCXXConstructorDeclaration( 237 cast<CXXConstructorDecl>(MD), 238 Ctor_Complete); 239 else 240 FInfo = &CGM.getTypes().arrangeCXXMethodDeclaration(MD); 241 242 llvm::Type *Ty = CGM.getTypes().GetFunctionType(*FInfo); 243 244 // C++ [class.virtual]p12: 245 // Explicit qualification with the scope operator (5.1) suppresses the 246 // virtual call mechanism. 247 // 248 // We also don't emit a virtual call if the base expression has a record type 249 // because then we know what the type is. 250 bool UseVirtualCall; 251 UseVirtualCall = MD->isVirtual() && !ME->hasQualifier() 252 && !canDevirtualizeMemberFunctionCalls(getContext(), 253 ME->getBase(), MD); 254 llvm::Value *Callee; 255 if (const CXXDestructorDecl *Dtor = dyn_cast<CXXDestructorDecl>(MD)) { 256 if (UseVirtualCall) { 257 Callee = BuildVirtualCall(Dtor, Dtor_Complete, This, Ty); 258 } else { 259 if (getContext().getLangOpts().AppleKext && 260 MD->isVirtual() && 261 ME->hasQualifier()) 262 Callee = BuildAppleKextVirtualCall(MD, ME->getQualifier(), Ty); 263 else 264 Callee = CGM.GetAddrOfFunction(GlobalDecl(Dtor, Dtor_Complete), Ty); 265 } 266 } else if (const CXXConstructorDecl *Ctor = 267 dyn_cast<CXXConstructorDecl>(MD)) { 268 Callee = CGM.GetAddrOfFunction(GlobalDecl(Ctor, Ctor_Complete), Ty); 269 } else if (UseVirtualCall) { 270 Callee = BuildVirtualCall(MD, This, Ty); 271 } else { 272 if (getContext().getLangOpts().AppleKext && 273 MD->isVirtual() && 274 ME->hasQualifier()) 275 Callee = BuildAppleKextVirtualCall(MD, ME->getQualifier(), Ty); 276 else 277 Callee = CGM.GetAddrOfFunction(MD, Ty); 278 } 279 280 return EmitCXXMemberCall(MD, Callee, ReturnValue, This, /*VTT=*/0, 281 CE->arg_begin(), CE->arg_end()); 282 } 283 284 RValue 285 CodeGenFunction::EmitCXXMemberPointerCallExpr(const CXXMemberCallExpr *E, 286 ReturnValueSlot ReturnValue) { 287 const BinaryOperator *BO = 288 cast<BinaryOperator>(E->getCallee()->IgnoreParens()); 289 const Expr *BaseExpr = BO->getLHS(); 290 const Expr *MemFnExpr = BO->getRHS(); 291 292 const MemberPointerType *MPT = 293 MemFnExpr->getType()->castAs<MemberPointerType>(); 294 295 const FunctionProtoType *FPT = 296 MPT->getPointeeType()->castAs<FunctionProtoType>(); 297 const CXXRecordDecl *RD = 298 cast<CXXRecordDecl>(MPT->getClass()->getAs<RecordType>()->getDecl()); 299 300 // Get the member function pointer. 301 llvm::Value *MemFnPtr = EmitScalarExpr(MemFnExpr); 302 303 // Emit the 'this' pointer. 304 llvm::Value *This; 305 306 if (BO->getOpcode() == BO_PtrMemI) 307 This = EmitScalarExpr(BaseExpr); 308 else 309 This = EmitLValue(BaseExpr).getAddress(); 310 311 // Ask the ABI to load the callee. Note that This is modified. 312 llvm::Value *Callee = 313 CGM.getCXXABI().EmitLoadOfMemberFunctionPointer(*this, This, MemFnPtr, MPT); 314 315 CallArgList Args; 316 317 QualType ThisType = 318 getContext().getPointerType(getContext().getTagDeclType(RD)); 319 320 // Push the this ptr. 321 Args.add(RValue::get(This), ThisType); 322 323 // And the rest of the call args 324 EmitCallArgs(Args, FPT, E->arg_begin(), E->arg_end()); 325 return EmitCall(CGM.getTypes().arrangeFunctionCall(Args, FPT), Callee, 326 ReturnValue, Args); 327 } 328 329 RValue 330 CodeGenFunction::EmitCXXOperatorMemberCallExpr(const CXXOperatorCallExpr *E, 331 const CXXMethodDecl *MD, 332 ReturnValueSlot ReturnValue) { 333 assert(MD->isInstance() && 334 "Trying to emit a member call expr on a static method!"); 335 LValue LV = EmitLValue(E->getArg(0)); 336 llvm::Value *This = LV.getAddress(); 337 338 if ((MD->isCopyAssignmentOperator() || MD->isMoveAssignmentOperator()) && 339 MD->isTrivial()) { 340 llvm::Value *Src = EmitLValue(E->getArg(1)).getAddress(); 341 QualType Ty = E->getType(); 342 EmitAggregateCopy(This, Src, Ty); 343 return RValue::get(This); 344 } 345 346 llvm::Value *Callee = EmitCXXOperatorMemberCallee(E, MD, This); 347 return EmitCXXMemberCall(MD, Callee, ReturnValue, This, /*VTT=*/0, 348 E->arg_begin() + 1, E->arg_end()); 349 } 350 351 RValue CodeGenFunction::EmitCUDAKernelCallExpr(const CUDAKernelCallExpr *E, 352 ReturnValueSlot ReturnValue) { 353 return CGM.getCUDARuntime().EmitCUDAKernelCallExpr(*this, E, ReturnValue); 354 } 355 356 static void EmitNullBaseClassInitialization(CodeGenFunction &CGF, 357 llvm::Value *DestPtr, 358 const CXXRecordDecl *Base) { 359 if (Base->isEmpty()) 360 return; 361 362 DestPtr = CGF.EmitCastToVoidPtr(DestPtr); 363 364 const ASTRecordLayout &Layout = CGF.getContext().getASTRecordLayout(Base); 365 CharUnits Size = Layout.getNonVirtualSize(); 366 CharUnits Align = Layout.getNonVirtualAlign(); 367 368 llvm::Value *SizeVal = CGF.CGM.getSize(Size); 369 370 // If the type contains a pointer to data member we can't memset it to zero. 371 // Instead, create a null constant and copy it to the destination. 372 // TODO: there are other patterns besides zero that we can usefully memset, 373 // like -1, which happens to be the pattern used by member-pointers. 374 // TODO: isZeroInitializable can be over-conservative in the case where a 375 // virtual base contains a member pointer. 376 if (!CGF.CGM.getTypes().isZeroInitializable(Base)) { 377 llvm::Constant *NullConstant = CGF.CGM.EmitNullConstantForBase(Base); 378 379 llvm::GlobalVariable *NullVariable = 380 new llvm::GlobalVariable(CGF.CGM.getModule(), NullConstant->getType(), 381 /*isConstant=*/true, 382 llvm::GlobalVariable::PrivateLinkage, 383 NullConstant, Twine()); 384 NullVariable->setAlignment(Align.getQuantity()); 385 llvm::Value *SrcPtr = CGF.EmitCastToVoidPtr(NullVariable); 386 387 // Get and call the appropriate llvm.memcpy overload. 388 CGF.Builder.CreateMemCpy(DestPtr, SrcPtr, SizeVal, Align.getQuantity()); 389 return; 390 } 391 392 // Otherwise, just memset the whole thing to zero. This is legal 393 // because in LLVM, all default initializers (other than the ones we just 394 // handled above) are guaranteed to have a bit pattern of all zeros. 395 CGF.Builder.CreateMemSet(DestPtr, CGF.Builder.getInt8(0), SizeVal, 396 Align.getQuantity()); 397 } 398 399 void 400 CodeGenFunction::EmitCXXConstructExpr(const CXXConstructExpr *E, 401 AggValueSlot Dest) { 402 assert(!Dest.isIgnored() && "Must have a destination!"); 403 const CXXConstructorDecl *CD = E->getConstructor(); 404 405 // If we require zero initialization before (or instead of) calling the 406 // constructor, as can be the case with a non-user-provided default 407 // constructor, emit the zero initialization now, unless destination is 408 // already zeroed. 409 if (E->requiresZeroInitialization() && !Dest.isZeroed()) { 410 switch (E->getConstructionKind()) { 411 case CXXConstructExpr::CK_Delegating: 412 assert(0 && "Delegating constructor should not need zeroing"); 413 case CXXConstructExpr::CK_Complete: 414 EmitNullInitialization(Dest.getAddr(), E->getType()); 415 break; 416 case CXXConstructExpr::CK_VirtualBase: 417 case CXXConstructExpr::CK_NonVirtualBase: 418 EmitNullBaseClassInitialization(*this, Dest.getAddr(), CD->getParent()); 419 break; 420 } 421 } 422 423 // If this is a call to a trivial default constructor, do nothing. 424 if (CD->isTrivial() && CD->isDefaultConstructor()) 425 return; 426 427 // Elide the constructor if we're constructing from a temporary. 428 // The temporary check is required because Sema sets this on NRVO 429 // returns. 430 if (getContext().getLangOpts().ElideConstructors && E->isElidable()) { 431 assert(getContext().hasSameUnqualifiedType(E->getType(), 432 E->getArg(0)->getType())); 433 if (E->getArg(0)->isTemporaryObject(getContext(), CD->getParent())) { 434 EmitAggExpr(E->getArg(0), Dest); 435 return; 436 } 437 } 438 439 if (const ConstantArrayType *arrayType 440 = getContext().getAsConstantArrayType(E->getType())) { 441 EmitCXXAggrConstructorCall(CD, arrayType, Dest.getAddr(), 442 E->arg_begin(), E->arg_end()); 443 } else { 444 CXXCtorType Type = Ctor_Complete; 445 bool ForVirtualBase = false; 446 447 switch (E->getConstructionKind()) { 448 case CXXConstructExpr::CK_Delegating: 449 // We should be emitting a constructor; GlobalDecl will assert this 450 Type = CurGD.getCtorType(); 451 break; 452 453 case CXXConstructExpr::CK_Complete: 454 Type = Ctor_Complete; 455 break; 456 457 case CXXConstructExpr::CK_VirtualBase: 458 ForVirtualBase = true; 459 // fall-through 460 461 case CXXConstructExpr::CK_NonVirtualBase: 462 Type = Ctor_Base; 463 } 464 465 // Call the constructor. 466 EmitCXXConstructorCall(CD, Type, ForVirtualBase, Dest.getAddr(), 467 E->arg_begin(), E->arg_end()); 468 } 469 } 470 471 void 472 CodeGenFunction::EmitSynthesizedCXXCopyCtor(llvm::Value *Dest, 473 llvm::Value *Src, 474 const Expr *Exp) { 475 if (const ExprWithCleanups *E = dyn_cast<ExprWithCleanups>(Exp)) 476 Exp = E->getSubExpr(); 477 assert(isa<CXXConstructExpr>(Exp) && 478 "EmitSynthesizedCXXCopyCtor - unknown copy ctor expr"); 479 const CXXConstructExpr* E = cast<CXXConstructExpr>(Exp); 480 const CXXConstructorDecl *CD = E->getConstructor(); 481 RunCleanupsScope Scope(*this); 482 483 // If we require zero initialization before (or instead of) calling the 484 // constructor, as can be the case with a non-user-provided default 485 // constructor, emit the zero initialization now. 486 // FIXME. Do I still need this for a copy ctor synthesis? 487 if (E->requiresZeroInitialization()) 488 EmitNullInitialization(Dest, E->getType()); 489 490 assert(!getContext().getAsConstantArrayType(E->getType()) 491 && "EmitSynthesizedCXXCopyCtor - Copied-in Array"); 492 EmitSynthesizedCXXCopyCtorCall(CD, Dest, Src, 493 E->arg_begin(), E->arg_end()); 494 } 495 496 static CharUnits CalculateCookiePadding(CodeGenFunction &CGF, 497 const CXXNewExpr *E) { 498 if (!E->isArray()) 499 return CharUnits::Zero(); 500 501 // No cookie is required if the operator new[] being used is the 502 // reserved placement operator new[]. 503 if (E->getOperatorNew()->isReservedGlobalPlacementOperator()) 504 return CharUnits::Zero(); 505 506 return CGF.CGM.getCXXABI().GetArrayCookieSize(E); 507 } 508 509 static llvm::Value *EmitCXXNewAllocSize(CodeGenFunction &CGF, 510 const CXXNewExpr *e, 511 unsigned minElements, 512 llvm::Value *&numElements, 513 llvm::Value *&sizeWithoutCookie) { 514 QualType type = e->getAllocatedType(); 515 516 if (!e->isArray()) { 517 CharUnits typeSize = CGF.getContext().getTypeSizeInChars(type); 518 sizeWithoutCookie 519 = llvm::ConstantInt::get(CGF.SizeTy, typeSize.getQuantity()); 520 return sizeWithoutCookie; 521 } 522 523 // The width of size_t. 524 unsigned sizeWidth = CGF.SizeTy->getBitWidth(); 525 526 // Figure out the cookie size. 527 llvm::APInt cookieSize(sizeWidth, 528 CalculateCookiePadding(CGF, e).getQuantity()); 529 530 // Emit the array size expression. 531 // We multiply the size of all dimensions for NumElements. 532 // e.g for 'int[2][3]', ElemType is 'int' and NumElements is 6. 533 numElements = CGF.EmitScalarExpr(e->getArraySize()); 534 assert(isa<llvm::IntegerType>(numElements->getType())); 535 536 // The number of elements can be have an arbitrary integer type; 537 // essentially, we need to multiply it by a constant factor, add a 538 // cookie size, and verify that the result is representable as a 539 // size_t. That's just a gloss, though, and it's wrong in one 540 // important way: if the count is negative, it's an error even if 541 // the cookie size would bring the total size >= 0. 542 bool isSigned 543 = e->getArraySize()->getType()->isSignedIntegerOrEnumerationType(); 544 llvm::IntegerType *numElementsType 545 = cast<llvm::IntegerType>(numElements->getType()); 546 unsigned numElementsWidth = numElementsType->getBitWidth(); 547 548 // Compute the constant factor. 549 llvm::APInt arraySizeMultiplier(sizeWidth, 1); 550 while (const ConstantArrayType *CAT 551 = CGF.getContext().getAsConstantArrayType(type)) { 552 type = CAT->getElementType(); 553 arraySizeMultiplier *= CAT->getSize(); 554 } 555 556 CharUnits typeSize = CGF.getContext().getTypeSizeInChars(type); 557 llvm::APInt typeSizeMultiplier(sizeWidth, typeSize.getQuantity()); 558 typeSizeMultiplier *= arraySizeMultiplier; 559 560 // This will be a size_t. 561 llvm::Value *size; 562 563 // If someone is doing 'new int[42]' there is no need to do a dynamic check. 564 // Don't bloat the -O0 code. 565 if (llvm::ConstantInt *numElementsC = 566 dyn_cast<llvm::ConstantInt>(numElements)) { 567 const llvm::APInt &count = numElementsC->getValue(); 568 569 bool hasAnyOverflow = false; 570 571 // If 'count' was a negative number, it's an overflow. 572 if (isSigned && count.isNegative()) 573 hasAnyOverflow = true; 574 575 // We want to do all this arithmetic in size_t. If numElements is 576 // wider than that, check whether it's already too big, and if so, 577 // overflow. 578 else if (numElementsWidth > sizeWidth && 579 numElementsWidth - sizeWidth > count.countLeadingZeros()) 580 hasAnyOverflow = true; 581 582 // Okay, compute a count at the right width. 583 llvm::APInt adjustedCount = count.zextOrTrunc(sizeWidth); 584 585 // If there is a brace-initializer, we cannot allocate fewer elements than 586 // there are initializers. If we do, that's treated like an overflow. 587 if (adjustedCount.ult(minElements)) 588 hasAnyOverflow = true; 589 590 // Scale numElements by that. This might overflow, but we don't 591 // care because it only overflows if allocationSize does, too, and 592 // if that overflows then we shouldn't use this. 593 numElements = llvm::ConstantInt::get(CGF.SizeTy, 594 adjustedCount * arraySizeMultiplier); 595 596 // Compute the size before cookie, and track whether it overflowed. 597 bool overflow; 598 llvm::APInt allocationSize 599 = adjustedCount.umul_ov(typeSizeMultiplier, overflow); 600 hasAnyOverflow |= overflow; 601 602 // Add in the cookie, and check whether it's overflowed. 603 if (cookieSize != 0) { 604 // Save the current size without a cookie. This shouldn't be 605 // used if there was overflow. 606 sizeWithoutCookie = llvm::ConstantInt::get(CGF.SizeTy, allocationSize); 607 608 allocationSize = allocationSize.uadd_ov(cookieSize, overflow); 609 hasAnyOverflow |= overflow; 610 } 611 612 // On overflow, produce a -1 so operator new will fail. 613 if (hasAnyOverflow) { 614 size = llvm::Constant::getAllOnesValue(CGF.SizeTy); 615 } else { 616 size = llvm::ConstantInt::get(CGF.SizeTy, allocationSize); 617 } 618 619 // Otherwise, we might need to use the overflow intrinsics. 620 } else { 621 // There are up to five conditions we need to test for: 622 // 1) if isSigned, we need to check whether numElements is negative; 623 // 2) if numElementsWidth > sizeWidth, we need to check whether 624 // numElements is larger than something representable in size_t; 625 // 3) if minElements > 0, we need to check whether numElements is smaller 626 // than that. 627 // 4) we need to compute 628 // sizeWithoutCookie := numElements * typeSizeMultiplier 629 // and check whether it overflows; and 630 // 5) if we need a cookie, we need to compute 631 // size := sizeWithoutCookie + cookieSize 632 // and check whether it overflows. 633 634 llvm::Value *hasOverflow = 0; 635 636 // If numElementsWidth > sizeWidth, then one way or another, we're 637 // going to have to do a comparison for (2), and this happens to 638 // take care of (1), too. 639 if (numElementsWidth > sizeWidth) { 640 llvm::APInt threshold(numElementsWidth, 1); 641 threshold <<= sizeWidth; 642 643 llvm::Value *thresholdV 644 = llvm::ConstantInt::get(numElementsType, threshold); 645 646 hasOverflow = CGF.Builder.CreateICmpUGE(numElements, thresholdV); 647 numElements = CGF.Builder.CreateTrunc(numElements, CGF.SizeTy); 648 649 // Otherwise, if we're signed, we want to sext up to size_t. 650 } else if (isSigned) { 651 if (numElementsWidth < sizeWidth) 652 numElements = CGF.Builder.CreateSExt(numElements, CGF.SizeTy); 653 654 // If there's a non-1 type size multiplier, then we can do the 655 // signedness check at the same time as we do the multiply 656 // because a negative number times anything will cause an 657 // unsigned overflow. Otherwise, we have to do it here. But at least 658 // in this case, we can subsume the >= minElements check. 659 if (typeSizeMultiplier == 1) 660 hasOverflow = CGF.Builder.CreateICmpSLT(numElements, 661 llvm::ConstantInt::get(CGF.SizeTy, minElements)); 662 663 // Otherwise, zext up to size_t if necessary. 664 } else if (numElementsWidth < sizeWidth) { 665 numElements = CGF.Builder.CreateZExt(numElements, CGF.SizeTy); 666 } 667 668 assert(numElements->getType() == CGF.SizeTy); 669 670 if (minElements) { 671 // Don't allow allocation of fewer elements than we have initializers. 672 if (!hasOverflow) { 673 hasOverflow = CGF.Builder.CreateICmpULT(numElements, 674 llvm::ConstantInt::get(CGF.SizeTy, minElements)); 675 } else if (numElementsWidth > sizeWidth) { 676 // The other existing overflow subsumes this check. 677 // We do an unsigned comparison, since any signed value < -1 is 678 // taken care of either above or below. 679 hasOverflow = CGF.Builder.CreateOr(hasOverflow, 680 CGF.Builder.CreateICmpULT(numElements, 681 llvm::ConstantInt::get(CGF.SizeTy, minElements))); 682 } 683 } 684 685 size = numElements; 686 687 // Multiply by the type size if necessary. This multiplier 688 // includes all the factors for nested arrays. 689 // 690 // This step also causes numElements to be scaled up by the 691 // nested-array factor if necessary. Overflow on this computation 692 // can be ignored because the result shouldn't be used if 693 // allocation fails. 694 if (typeSizeMultiplier != 1) { 695 llvm::Value *umul_with_overflow 696 = CGF.CGM.getIntrinsic(llvm::Intrinsic::umul_with_overflow, CGF.SizeTy); 697 698 llvm::Value *tsmV = 699 llvm::ConstantInt::get(CGF.SizeTy, typeSizeMultiplier); 700 llvm::Value *result = 701 CGF.Builder.CreateCall2(umul_with_overflow, size, tsmV); 702 703 llvm::Value *overflowed = CGF.Builder.CreateExtractValue(result, 1); 704 if (hasOverflow) 705 hasOverflow = CGF.Builder.CreateOr(hasOverflow, overflowed); 706 else 707 hasOverflow = overflowed; 708 709 size = CGF.Builder.CreateExtractValue(result, 0); 710 711 // Also scale up numElements by the array size multiplier. 712 if (arraySizeMultiplier != 1) { 713 // If the base element type size is 1, then we can re-use the 714 // multiply we just did. 715 if (typeSize.isOne()) { 716 assert(arraySizeMultiplier == typeSizeMultiplier); 717 numElements = size; 718 719 // Otherwise we need a separate multiply. 720 } else { 721 llvm::Value *asmV = 722 llvm::ConstantInt::get(CGF.SizeTy, arraySizeMultiplier); 723 numElements = CGF.Builder.CreateMul(numElements, asmV); 724 } 725 } 726 } else { 727 // numElements doesn't need to be scaled. 728 assert(arraySizeMultiplier == 1); 729 } 730 731 // Add in the cookie size if necessary. 732 if (cookieSize != 0) { 733 sizeWithoutCookie = size; 734 735 llvm::Value *uadd_with_overflow 736 = CGF.CGM.getIntrinsic(llvm::Intrinsic::uadd_with_overflow, CGF.SizeTy); 737 738 llvm::Value *cookieSizeV = llvm::ConstantInt::get(CGF.SizeTy, cookieSize); 739 llvm::Value *result = 740 CGF.Builder.CreateCall2(uadd_with_overflow, size, cookieSizeV); 741 742 llvm::Value *overflowed = CGF.Builder.CreateExtractValue(result, 1); 743 if (hasOverflow) 744 hasOverflow = CGF.Builder.CreateOr(hasOverflow, overflowed); 745 else 746 hasOverflow = overflowed; 747 748 size = CGF.Builder.CreateExtractValue(result, 0); 749 } 750 751 // If we had any possibility of dynamic overflow, make a select to 752 // overwrite 'size' with an all-ones value, which should cause 753 // operator new to throw. 754 if (hasOverflow) 755 size = CGF.Builder.CreateSelect(hasOverflow, 756 llvm::Constant::getAllOnesValue(CGF.SizeTy), 757 size); 758 } 759 760 if (cookieSize == 0) 761 sizeWithoutCookie = size; 762 else 763 assert(sizeWithoutCookie && "didn't set sizeWithoutCookie?"); 764 765 return size; 766 } 767 768 static void StoreAnyExprIntoOneUnit(CodeGenFunction &CGF, const Expr *Init, 769 QualType AllocType, llvm::Value *NewPtr) { 770 771 CharUnits Alignment = CGF.getContext().getTypeAlignInChars(AllocType); 772 if (!CGF.hasAggregateLLVMType(AllocType)) 773 CGF.EmitScalarInit(Init, 0, CGF.MakeAddrLValue(NewPtr, AllocType, 774 Alignment), 775 false); 776 else if (AllocType->isAnyComplexType()) 777 CGF.EmitComplexExprIntoAddr(Init, NewPtr, 778 AllocType.isVolatileQualified()); 779 else { 780 AggValueSlot Slot 781 = AggValueSlot::forAddr(NewPtr, Alignment, AllocType.getQualifiers(), 782 AggValueSlot::IsDestructed, 783 AggValueSlot::DoesNotNeedGCBarriers, 784 AggValueSlot::IsNotAliased, 785 AggValueSlot::IsCompleteObject); 786 CGF.EmitAggExpr(Init, Slot); 787 788 CGF.MaybeEmitStdInitializerListCleanup(NewPtr, Init); 789 } 790 } 791 792 void 793 CodeGenFunction::EmitNewArrayInitializer(const CXXNewExpr *E, 794 QualType elementType, 795 llvm::Value *beginPtr, 796 llvm::Value *numElements) { 797 if (!E->hasInitializer()) 798 return; // We have a POD type. 799 800 llvm::Value *explicitPtr = beginPtr; 801 // Find the end of the array, hoisted out of the loop. 802 llvm::Value *endPtr = 803 Builder.CreateInBoundsGEP(beginPtr, numElements, "array.end"); 804 805 unsigned initializerElements = 0; 806 807 const Expr *Init = E->getInitializer(); 808 llvm::AllocaInst *endOfInit = 0; 809 QualType::DestructionKind dtorKind = elementType.isDestructedType(); 810 EHScopeStack::stable_iterator cleanup; 811 llvm::Instruction *cleanupDominator = 0; 812 // If the initializer is an initializer list, first do the explicit elements. 813 if (const InitListExpr *ILE = dyn_cast<InitListExpr>(Init)) { 814 initializerElements = ILE->getNumInits(); 815 816 // Enter a partial-destruction cleanup if necessary. 817 if (needsEHCleanup(dtorKind)) { 818 // In principle we could tell the cleanup where we are more 819 // directly, but the control flow can get so varied here that it 820 // would actually be quite complex. Therefore we go through an 821 // alloca. 822 endOfInit = CreateTempAlloca(beginPtr->getType(), "array.endOfInit"); 823 cleanupDominator = Builder.CreateStore(beginPtr, endOfInit); 824 pushIrregularPartialArrayCleanup(beginPtr, endOfInit, elementType, 825 getDestroyer(dtorKind)); 826 cleanup = EHStack.stable_begin(); 827 } 828 829 for (unsigned i = 0, e = ILE->getNumInits(); i != e; ++i) { 830 // Tell the cleanup that it needs to destroy up to this 831 // element. TODO: some of these stores can be trivially 832 // observed to be unnecessary. 833 if (endOfInit) Builder.CreateStore(explicitPtr, endOfInit); 834 StoreAnyExprIntoOneUnit(*this, ILE->getInit(i), elementType, explicitPtr); 835 explicitPtr =Builder.CreateConstGEP1_32(explicitPtr, 1, "array.exp.next"); 836 } 837 838 // The remaining elements are filled with the array filler expression. 839 Init = ILE->getArrayFiller(); 840 } 841 842 // Create the continuation block. 843 llvm::BasicBlock *contBB = createBasicBlock("new.loop.end"); 844 845 // If the number of elements isn't constant, we have to now check if there is 846 // anything left to initialize. 847 if (llvm::ConstantInt *constNum = dyn_cast<llvm::ConstantInt>(numElements)) { 848 // If all elements have already been initialized, skip the whole loop. 849 if (constNum->getZExtValue() <= initializerElements) { 850 // If there was a cleanup, deactivate it. 851 if (cleanupDominator) 852 DeactivateCleanupBlock(cleanup, cleanupDominator);; 853 return; 854 } 855 } else { 856 llvm::BasicBlock *nonEmptyBB = createBasicBlock("new.loop.nonempty"); 857 llvm::Value *isEmpty = Builder.CreateICmpEQ(explicitPtr, endPtr, 858 "array.isempty"); 859 Builder.CreateCondBr(isEmpty, contBB, nonEmptyBB); 860 EmitBlock(nonEmptyBB); 861 } 862 863 // Enter the loop. 864 llvm::BasicBlock *entryBB = Builder.GetInsertBlock(); 865 llvm::BasicBlock *loopBB = createBasicBlock("new.loop"); 866 867 EmitBlock(loopBB); 868 869 // Set up the current-element phi. 870 llvm::PHINode *curPtr = 871 Builder.CreatePHI(explicitPtr->getType(), 2, "array.cur"); 872 curPtr->addIncoming(explicitPtr, entryBB); 873 874 // Store the new cleanup position for irregular cleanups. 875 if (endOfInit) Builder.CreateStore(curPtr, endOfInit); 876 877 // Enter a partial-destruction cleanup if necessary. 878 if (!cleanupDominator && needsEHCleanup(dtorKind)) { 879 pushRegularPartialArrayCleanup(beginPtr, curPtr, elementType, 880 getDestroyer(dtorKind)); 881 cleanup = EHStack.stable_begin(); 882 cleanupDominator = Builder.CreateUnreachable(); 883 } 884 885 // Emit the initializer into this element. 886 StoreAnyExprIntoOneUnit(*this, Init, E->getAllocatedType(), curPtr); 887 888 // Leave the cleanup if we entered one. 889 if (cleanupDominator) { 890 DeactivateCleanupBlock(cleanup, cleanupDominator); 891 cleanupDominator->eraseFromParent(); 892 } 893 894 // Advance to the next element. 895 llvm::Value *nextPtr = Builder.CreateConstGEP1_32(curPtr, 1, "array.next"); 896 897 // Check whether we've gotten to the end of the array and, if so, 898 // exit the loop. 899 llvm::Value *isEnd = Builder.CreateICmpEQ(nextPtr, endPtr, "array.atend"); 900 Builder.CreateCondBr(isEnd, contBB, loopBB); 901 curPtr->addIncoming(nextPtr, Builder.GetInsertBlock()); 902 903 EmitBlock(contBB); 904 } 905 906 static void EmitZeroMemSet(CodeGenFunction &CGF, QualType T, 907 llvm::Value *NewPtr, llvm::Value *Size) { 908 CGF.EmitCastToVoidPtr(NewPtr); 909 CharUnits Alignment = CGF.getContext().getTypeAlignInChars(T); 910 CGF.Builder.CreateMemSet(NewPtr, CGF.Builder.getInt8(0), Size, 911 Alignment.getQuantity(), false); 912 } 913 914 static void EmitNewInitializer(CodeGenFunction &CGF, const CXXNewExpr *E, 915 QualType ElementType, 916 llvm::Value *NewPtr, 917 llvm::Value *NumElements, 918 llvm::Value *AllocSizeWithoutCookie) { 919 const Expr *Init = E->getInitializer(); 920 if (E->isArray()) { 921 if (const CXXConstructExpr *CCE = dyn_cast_or_null<CXXConstructExpr>(Init)){ 922 CXXConstructorDecl *Ctor = CCE->getConstructor(); 923 bool RequiresZeroInitialization = false; 924 if (Ctor->isTrivial()) { 925 // If new expression did not specify value-initialization, then there 926 // is no initialization. 927 if (!CCE->requiresZeroInitialization() || Ctor->getParent()->isEmpty()) 928 return; 929 930 if (CGF.CGM.getTypes().isZeroInitializable(ElementType)) { 931 // Optimization: since zero initialization will just set the memory 932 // to all zeroes, generate a single memset to do it in one shot. 933 EmitZeroMemSet(CGF, ElementType, NewPtr, AllocSizeWithoutCookie); 934 return; 935 } 936 937 RequiresZeroInitialization = true; 938 } 939 940 CGF.EmitCXXAggrConstructorCall(Ctor, NumElements, NewPtr, 941 CCE->arg_begin(), CCE->arg_end(), 942 RequiresZeroInitialization); 943 return; 944 } else if (Init && isa<ImplicitValueInitExpr>(Init) && 945 CGF.CGM.getTypes().isZeroInitializable(ElementType)) { 946 // Optimization: since zero initialization will just set the memory 947 // to all zeroes, generate a single memset to do it in one shot. 948 EmitZeroMemSet(CGF, ElementType, NewPtr, AllocSizeWithoutCookie); 949 return; 950 } 951 CGF.EmitNewArrayInitializer(E, ElementType, NewPtr, NumElements); 952 return; 953 } 954 955 if (!Init) 956 return; 957 958 StoreAnyExprIntoOneUnit(CGF, Init, E->getAllocatedType(), NewPtr); 959 } 960 961 namespace { 962 /// A cleanup to call the given 'operator delete' function upon 963 /// abnormal exit from a new expression. 964 class CallDeleteDuringNew : public EHScopeStack::Cleanup { 965 size_t NumPlacementArgs; 966 const FunctionDecl *OperatorDelete; 967 llvm::Value *Ptr; 968 llvm::Value *AllocSize; 969 970 RValue *getPlacementArgs() { return reinterpret_cast<RValue*>(this+1); } 971 972 public: 973 static size_t getExtraSize(size_t NumPlacementArgs) { 974 return NumPlacementArgs * sizeof(RValue); 975 } 976 977 CallDeleteDuringNew(size_t NumPlacementArgs, 978 const FunctionDecl *OperatorDelete, 979 llvm::Value *Ptr, 980 llvm::Value *AllocSize) 981 : NumPlacementArgs(NumPlacementArgs), OperatorDelete(OperatorDelete), 982 Ptr(Ptr), AllocSize(AllocSize) {} 983 984 void setPlacementArg(unsigned I, RValue Arg) { 985 assert(I < NumPlacementArgs && "index out of range"); 986 getPlacementArgs()[I] = Arg; 987 } 988 989 void Emit(CodeGenFunction &CGF, Flags flags) { 990 const FunctionProtoType *FPT 991 = OperatorDelete->getType()->getAs<FunctionProtoType>(); 992 assert(FPT->getNumArgs() == NumPlacementArgs + 1 || 993 (FPT->getNumArgs() == 2 && NumPlacementArgs == 0)); 994 995 CallArgList DeleteArgs; 996 997 // The first argument is always a void*. 998 FunctionProtoType::arg_type_iterator AI = FPT->arg_type_begin(); 999 DeleteArgs.add(RValue::get(Ptr), *AI++); 1000 1001 // A member 'operator delete' can take an extra 'size_t' argument. 1002 if (FPT->getNumArgs() == NumPlacementArgs + 2) 1003 DeleteArgs.add(RValue::get(AllocSize), *AI++); 1004 1005 // Pass the rest of the arguments, which must match exactly. 1006 for (unsigned I = 0; I != NumPlacementArgs; ++I) 1007 DeleteArgs.add(getPlacementArgs()[I], *AI++); 1008 1009 // Call 'operator delete'. 1010 CGF.EmitCall(CGF.CGM.getTypes().arrangeFunctionCall(DeleteArgs, FPT), 1011 CGF.CGM.GetAddrOfFunction(OperatorDelete), 1012 ReturnValueSlot(), DeleteArgs, OperatorDelete); 1013 } 1014 }; 1015 1016 /// A cleanup to call the given 'operator delete' function upon 1017 /// abnormal exit from a new expression when the new expression is 1018 /// conditional. 1019 class CallDeleteDuringConditionalNew : public EHScopeStack::Cleanup { 1020 size_t NumPlacementArgs; 1021 const FunctionDecl *OperatorDelete; 1022 DominatingValue<RValue>::saved_type Ptr; 1023 DominatingValue<RValue>::saved_type AllocSize; 1024 1025 DominatingValue<RValue>::saved_type *getPlacementArgs() { 1026 return reinterpret_cast<DominatingValue<RValue>::saved_type*>(this+1); 1027 } 1028 1029 public: 1030 static size_t getExtraSize(size_t NumPlacementArgs) { 1031 return NumPlacementArgs * sizeof(DominatingValue<RValue>::saved_type); 1032 } 1033 1034 CallDeleteDuringConditionalNew(size_t NumPlacementArgs, 1035 const FunctionDecl *OperatorDelete, 1036 DominatingValue<RValue>::saved_type Ptr, 1037 DominatingValue<RValue>::saved_type AllocSize) 1038 : NumPlacementArgs(NumPlacementArgs), OperatorDelete(OperatorDelete), 1039 Ptr(Ptr), AllocSize(AllocSize) {} 1040 1041 void setPlacementArg(unsigned I, DominatingValue<RValue>::saved_type Arg) { 1042 assert(I < NumPlacementArgs && "index out of range"); 1043 getPlacementArgs()[I] = Arg; 1044 } 1045 1046 void Emit(CodeGenFunction &CGF, Flags flags) { 1047 const FunctionProtoType *FPT 1048 = OperatorDelete->getType()->getAs<FunctionProtoType>(); 1049 assert(FPT->getNumArgs() == NumPlacementArgs + 1 || 1050 (FPT->getNumArgs() == 2 && NumPlacementArgs == 0)); 1051 1052 CallArgList DeleteArgs; 1053 1054 // The first argument is always a void*. 1055 FunctionProtoType::arg_type_iterator AI = FPT->arg_type_begin(); 1056 DeleteArgs.add(Ptr.restore(CGF), *AI++); 1057 1058 // A member 'operator delete' can take an extra 'size_t' argument. 1059 if (FPT->getNumArgs() == NumPlacementArgs + 2) { 1060 RValue RV = AllocSize.restore(CGF); 1061 DeleteArgs.add(RV, *AI++); 1062 } 1063 1064 // Pass the rest of the arguments, which must match exactly. 1065 for (unsigned I = 0; I != NumPlacementArgs; ++I) { 1066 RValue RV = getPlacementArgs()[I].restore(CGF); 1067 DeleteArgs.add(RV, *AI++); 1068 } 1069 1070 // Call 'operator delete'. 1071 CGF.EmitCall(CGF.CGM.getTypes().arrangeFunctionCall(DeleteArgs, FPT), 1072 CGF.CGM.GetAddrOfFunction(OperatorDelete), 1073 ReturnValueSlot(), DeleteArgs, OperatorDelete); 1074 } 1075 }; 1076 } 1077 1078 /// Enter a cleanup to call 'operator delete' if the initializer in a 1079 /// new-expression throws. 1080 static void EnterNewDeleteCleanup(CodeGenFunction &CGF, 1081 const CXXNewExpr *E, 1082 llvm::Value *NewPtr, 1083 llvm::Value *AllocSize, 1084 const CallArgList &NewArgs) { 1085 // If we're not inside a conditional branch, then the cleanup will 1086 // dominate and we can do the easier (and more efficient) thing. 1087 if (!CGF.isInConditionalBranch()) { 1088 CallDeleteDuringNew *Cleanup = CGF.EHStack 1089 .pushCleanupWithExtra<CallDeleteDuringNew>(EHCleanup, 1090 E->getNumPlacementArgs(), 1091 E->getOperatorDelete(), 1092 NewPtr, AllocSize); 1093 for (unsigned I = 0, N = E->getNumPlacementArgs(); I != N; ++I) 1094 Cleanup->setPlacementArg(I, NewArgs[I+1].RV); 1095 1096 return; 1097 } 1098 1099 // Otherwise, we need to save all this stuff. 1100 DominatingValue<RValue>::saved_type SavedNewPtr = 1101 DominatingValue<RValue>::save(CGF, RValue::get(NewPtr)); 1102 DominatingValue<RValue>::saved_type SavedAllocSize = 1103 DominatingValue<RValue>::save(CGF, RValue::get(AllocSize)); 1104 1105 CallDeleteDuringConditionalNew *Cleanup = CGF.EHStack 1106 .pushCleanupWithExtra<CallDeleteDuringConditionalNew>(EHCleanup, 1107 E->getNumPlacementArgs(), 1108 E->getOperatorDelete(), 1109 SavedNewPtr, 1110 SavedAllocSize); 1111 for (unsigned I = 0, N = E->getNumPlacementArgs(); I != N; ++I) 1112 Cleanup->setPlacementArg(I, 1113 DominatingValue<RValue>::save(CGF, NewArgs[I+1].RV)); 1114 1115 CGF.initFullExprCleanup(); 1116 } 1117 1118 llvm::Value *CodeGenFunction::EmitCXXNewExpr(const CXXNewExpr *E) { 1119 // The element type being allocated. 1120 QualType allocType = getContext().getBaseElementType(E->getAllocatedType()); 1121 1122 // 1. Build a call to the allocation function. 1123 FunctionDecl *allocator = E->getOperatorNew(); 1124 const FunctionProtoType *allocatorType = 1125 allocator->getType()->castAs<FunctionProtoType>(); 1126 1127 CallArgList allocatorArgs; 1128 1129 // The allocation size is the first argument. 1130 QualType sizeType = getContext().getSizeType(); 1131 1132 // If there is a brace-initializer, cannot allocate fewer elements than inits. 1133 unsigned minElements = 0; 1134 if (E->isArray() && E->hasInitializer()) { 1135 if (const InitListExpr *ILE = dyn_cast<InitListExpr>(E->getInitializer())) 1136 minElements = ILE->getNumInits(); 1137 } 1138 1139 llvm::Value *numElements = 0; 1140 llvm::Value *allocSizeWithoutCookie = 0; 1141 llvm::Value *allocSize = 1142 EmitCXXNewAllocSize(*this, E, minElements, numElements, 1143 allocSizeWithoutCookie); 1144 1145 allocatorArgs.add(RValue::get(allocSize), sizeType); 1146 1147 // Emit the rest of the arguments. 1148 // FIXME: Ideally, this should just use EmitCallArgs. 1149 CXXNewExpr::const_arg_iterator placementArg = E->placement_arg_begin(); 1150 1151 // First, use the types from the function type. 1152 // We start at 1 here because the first argument (the allocation size) 1153 // has already been emitted. 1154 for (unsigned i = 1, e = allocatorType->getNumArgs(); i != e; 1155 ++i, ++placementArg) { 1156 QualType argType = allocatorType->getArgType(i); 1157 1158 assert(getContext().hasSameUnqualifiedType(argType.getNonReferenceType(), 1159 placementArg->getType()) && 1160 "type mismatch in call argument!"); 1161 1162 EmitCallArg(allocatorArgs, *placementArg, argType); 1163 } 1164 1165 // Either we've emitted all the call args, or we have a call to a 1166 // variadic function. 1167 assert((placementArg == E->placement_arg_end() || 1168 allocatorType->isVariadic()) && 1169 "Extra arguments to non-variadic function!"); 1170 1171 // If we still have any arguments, emit them using the type of the argument. 1172 for (CXXNewExpr::const_arg_iterator placementArgsEnd = E->placement_arg_end(); 1173 placementArg != placementArgsEnd; ++placementArg) { 1174 EmitCallArg(allocatorArgs, *placementArg, placementArg->getType()); 1175 } 1176 1177 // Emit the allocation call. If the allocator is a global placement 1178 // operator, just "inline" it directly. 1179 RValue RV; 1180 if (allocator->isReservedGlobalPlacementOperator()) { 1181 assert(allocatorArgs.size() == 2); 1182 RV = allocatorArgs[1].RV; 1183 // TODO: kill any unnecessary computations done for the size 1184 // argument. 1185 } else { 1186 RV = EmitCall(CGM.getTypes().arrangeFunctionCall(allocatorArgs, 1187 allocatorType), 1188 CGM.GetAddrOfFunction(allocator), ReturnValueSlot(), 1189 allocatorArgs, allocator); 1190 } 1191 1192 // Emit a null check on the allocation result if the allocation 1193 // function is allowed to return null (because it has a non-throwing 1194 // exception spec; for this part, we inline 1195 // CXXNewExpr::shouldNullCheckAllocation()) and we have an 1196 // interesting initializer. 1197 bool nullCheck = allocatorType->isNothrow(getContext()) && 1198 (!allocType.isPODType(getContext()) || E->hasInitializer()); 1199 1200 llvm::BasicBlock *nullCheckBB = 0; 1201 llvm::BasicBlock *contBB = 0; 1202 1203 llvm::Value *allocation = RV.getScalarVal(); 1204 unsigned AS = 1205 cast<llvm::PointerType>(allocation->getType())->getAddressSpace(); 1206 1207 // The null-check means that the initializer is conditionally 1208 // evaluated. 1209 ConditionalEvaluation conditional(*this); 1210 1211 if (nullCheck) { 1212 conditional.begin(*this); 1213 1214 nullCheckBB = Builder.GetInsertBlock(); 1215 llvm::BasicBlock *notNullBB = createBasicBlock("new.notnull"); 1216 contBB = createBasicBlock("new.cont"); 1217 1218 llvm::Value *isNull = Builder.CreateIsNull(allocation, "new.isnull"); 1219 Builder.CreateCondBr(isNull, contBB, notNullBB); 1220 EmitBlock(notNullBB); 1221 } 1222 1223 // If there's an operator delete, enter a cleanup to call it if an 1224 // exception is thrown. 1225 EHScopeStack::stable_iterator operatorDeleteCleanup; 1226 llvm::Instruction *cleanupDominator = 0; 1227 if (E->getOperatorDelete() && 1228 !E->getOperatorDelete()->isReservedGlobalPlacementOperator()) { 1229 EnterNewDeleteCleanup(*this, E, allocation, allocSize, allocatorArgs); 1230 operatorDeleteCleanup = EHStack.stable_begin(); 1231 cleanupDominator = Builder.CreateUnreachable(); 1232 } 1233 1234 assert((allocSize == allocSizeWithoutCookie) == 1235 CalculateCookiePadding(*this, E).isZero()); 1236 if (allocSize != allocSizeWithoutCookie) { 1237 assert(E->isArray()); 1238 allocation = CGM.getCXXABI().InitializeArrayCookie(*this, allocation, 1239 numElements, 1240 E, allocType); 1241 } 1242 1243 llvm::Type *elementPtrTy 1244 = ConvertTypeForMem(allocType)->getPointerTo(AS); 1245 llvm::Value *result = Builder.CreateBitCast(allocation, elementPtrTy); 1246 1247 EmitNewInitializer(*this, E, allocType, result, numElements, 1248 allocSizeWithoutCookie); 1249 if (E->isArray()) { 1250 // NewPtr is a pointer to the base element type. If we're 1251 // allocating an array of arrays, we'll need to cast back to the 1252 // array pointer type. 1253 llvm::Type *resultType = ConvertTypeForMem(E->getType()); 1254 if (result->getType() != resultType) 1255 result = Builder.CreateBitCast(result, resultType); 1256 } 1257 1258 // Deactivate the 'operator delete' cleanup if we finished 1259 // initialization. 1260 if (operatorDeleteCleanup.isValid()) { 1261 DeactivateCleanupBlock(operatorDeleteCleanup, cleanupDominator); 1262 cleanupDominator->eraseFromParent(); 1263 } 1264 1265 if (nullCheck) { 1266 conditional.end(*this); 1267 1268 llvm::BasicBlock *notNullBB = Builder.GetInsertBlock(); 1269 EmitBlock(contBB); 1270 1271 llvm::PHINode *PHI = Builder.CreatePHI(result->getType(), 2); 1272 PHI->addIncoming(result, notNullBB); 1273 PHI->addIncoming(llvm::Constant::getNullValue(result->getType()), 1274 nullCheckBB); 1275 1276 result = PHI; 1277 } 1278 1279 return result; 1280 } 1281 1282 void CodeGenFunction::EmitDeleteCall(const FunctionDecl *DeleteFD, 1283 llvm::Value *Ptr, 1284 QualType DeleteTy) { 1285 assert(DeleteFD->getOverloadedOperator() == OO_Delete); 1286 1287 const FunctionProtoType *DeleteFTy = 1288 DeleteFD->getType()->getAs<FunctionProtoType>(); 1289 1290 CallArgList DeleteArgs; 1291 1292 // Check if we need to pass the size to the delete operator. 1293 llvm::Value *Size = 0; 1294 QualType SizeTy; 1295 if (DeleteFTy->getNumArgs() == 2) { 1296 SizeTy = DeleteFTy->getArgType(1); 1297 CharUnits DeleteTypeSize = getContext().getTypeSizeInChars(DeleteTy); 1298 Size = llvm::ConstantInt::get(ConvertType(SizeTy), 1299 DeleteTypeSize.getQuantity()); 1300 } 1301 1302 QualType ArgTy = DeleteFTy->getArgType(0); 1303 llvm::Value *DeletePtr = Builder.CreateBitCast(Ptr, ConvertType(ArgTy)); 1304 DeleteArgs.add(RValue::get(DeletePtr), ArgTy); 1305 1306 if (Size) 1307 DeleteArgs.add(RValue::get(Size), SizeTy); 1308 1309 // Emit the call to delete. 1310 EmitCall(CGM.getTypes().arrangeFunctionCall(DeleteArgs, DeleteFTy), 1311 CGM.GetAddrOfFunction(DeleteFD), ReturnValueSlot(), 1312 DeleteArgs, DeleteFD); 1313 } 1314 1315 namespace { 1316 /// Calls the given 'operator delete' on a single object. 1317 struct CallObjectDelete : EHScopeStack::Cleanup { 1318 llvm::Value *Ptr; 1319 const FunctionDecl *OperatorDelete; 1320 QualType ElementType; 1321 1322 CallObjectDelete(llvm::Value *Ptr, 1323 const FunctionDecl *OperatorDelete, 1324 QualType ElementType) 1325 : Ptr(Ptr), OperatorDelete(OperatorDelete), ElementType(ElementType) {} 1326 1327 void Emit(CodeGenFunction &CGF, Flags flags) { 1328 CGF.EmitDeleteCall(OperatorDelete, Ptr, ElementType); 1329 } 1330 }; 1331 } 1332 1333 /// Emit the code for deleting a single object. 1334 static void EmitObjectDelete(CodeGenFunction &CGF, 1335 const FunctionDecl *OperatorDelete, 1336 llvm::Value *Ptr, 1337 QualType ElementType, 1338 bool UseGlobalDelete) { 1339 // Find the destructor for the type, if applicable. If the 1340 // destructor is virtual, we'll just emit the vcall and return. 1341 const CXXDestructorDecl *Dtor = 0; 1342 if (const RecordType *RT = ElementType->getAs<RecordType>()) { 1343 CXXRecordDecl *RD = cast<CXXRecordDecl>(RT->getDecl()); 1344 if (RD->hasDefinition() && !RD->hasTrivialDestructor()) { 1345 Dtor = RD->getDestructor(); 1346 1347 if (Dtor->isVirtual()) { 1348 if (UseGlobalDelete) { 1349 // If we're supposed to call the global delete, make sure we do so 1350 // even if the destructor throws. 1351 CGF.EHStack.pushCleanup<CallObjectDelete>(NormalAndEHCleanup, 1352 Ptr, OperatorDelete, 1353 ElementType); 1354 } 1355 1356 llvm::Type *Ty = 1357 CGF.getTypes().GetFunctionType( 1358 CGF.getTypes().arrangeCXXDestructor(Dtor, Dtor_Complete)); 1359 1360 llvm::Value *Callee 1361 = CGF.BuildVirtualCall(Dtor, 1362 UseGlobalDelete? Dtor_Complete : Dtor_Deleting, 1363 Ptr, Ty); 1364 CGF.EmitCXXMemberCall(Dtor, Callee, ReturnValueSlot(), Ptr, /*VTT=*/0, 1365 0, 0); 1366 1367 if (UseGlobalDelete) { 1368 CGF.PopCleanupBlock(); 1369 } 1370 1371 return; 1372 } 1373 } 1374 } 1375 1376 // Make sure that we call delete even if the dtor throws. 1377 // This doesn't have to a conditional cleanup because we're going 1378 // to pop it off in a second. 1379 CGF.EHStack.pushCleanup<CallObjectDelete>(NormalAndEHCleanup, 1380 Ptr, OperatorDelete, ElementType); 1381 1382 if (Dtor) 1383 CGF.EmitCXXDestructorCall(Dtor, Dtor_Complete, 1384 /*ForVirtualBase=*/false, Ptr); 1385 else if (CGF.getLangOpts().ObjCAutoRefCount && 1386 ElementType->isObjCLifetimeType()) { 1387 switch (ElementType.getObjCLifetime()) { 1388 case Qualifiers::OCL_None: 1389 case Qualifiers::OCL_ExplicitNone: 1390 case Qualifiers::OCL_Autoreleasing: 1391 break; 1392 1393 case Qualifiers::OCL_Strong: { 1394 // Load the pointer value. 1395 llvm::Value *PtrValue = CGF.Builder.CreateLoad(Ptr, 1396 ElementType.isVolatileQualified()); 1397 1398 CGF.EmitARCRelease(PtrValue, /*precise*/ true); 1399 break; 1400 } 1401 1402 case Qualifiers::OCL_Weak: 1403 CGF.EmitARCDestroyWeak(Ptr); 1404 break; 1405 } 1406 } 1407 1408 CGF.PopCleanupBlock(); 1409 } 1410 1411 namespace { 1412 /// Calls the given 'operator delete' on an array of objects. 1413 struct CallArrayDelete : EHScopeStack::Cleanup { 1414 llvm::Value *Ptr; 1415 const FunctionDecl *OperatorDelete; 1416 llvm::Value *NumElements; 1417 QualType ElementType; 1418 CharUnits CookieSize; 1419 1420 CallArrayDelete(llvm::Value *Ptr, 1421 const FunctionDecl *OperatorDelete, 1422 llvm::Value *NumElements, 1423 QualType ElementType, 1424 CharUnits CookieSize) 1425 : Ptr(Ptr), OperatorDelete(OperatorDelete), NumElements(NumElements), 1426 ElementType(ElementType), CookieSize(CookieSize) {} 1427 1428 void Emit(CodeGenFunction &CGF, Flags flags) { 1429 const FunctionProtoType *DeleteFTy = 1430 OperatorDelete->getType()->getAs<FunctionProtoType>(); 1431 assert(DeleteFTy->getNumArgs() == 1 || DeleteFTy->getNumArgs() == 2); 1432 1433 CallArgList Args; 1434 1435 // Pass the pointer as the first argument. 1436 QualType VoidPtrTy = DeleteFTy->getArgType(0); 1437 llvm::Value *DeletePtr 1438 = CGF.Builder.CreateBitCast(Ptr, CGF.ConvertType(VoidPtrTy)); 1439 Args.add(RValue::get(DeletePtr), VoidPtrTy); 1440 1441 // Pass the original requested size as the second argument. 1442 if (DeleteFTy->getNumArgs() == 2) { 1443 QualType size_t = DeleteFTy->getArgType(1); 1444 llvm::IntegerType *SizeTy 1445 = cast<llvm::IntegerType>(CGF.ConvertType(size_t)); 1446 1447 CharUnits ElementTypeSize = 1448 CGF.CGM.getContext().getTypeSizeInChars(ElementType); 1449 1450 // The size of an element, multiplied by the number of elements. 1451 llvm::Value *Size 1452 = llvm::ConstantInt::get(SizeTy, ElementTypeSize.getQuantity()); 1453 Size = CGF.Builder.CreateMul(Size, NumElements); 1454 1455 // Plus the size of the cookie if applicable. 1456 if (!CookieSize.isZero()) { 1457 llvm::Value *CookieSizeV 1458 = llvm::ConstantInt::get(SizeTy, CookieSize.getQuantity()); 1459 Size = CGF.Builder.CreateAdd(Size, CookieSizeV); 1460 } 1461 1462 Args.add(RValue::get(Size), size_t); 1463 } 1464 1465 // Emit the call to delete. 1466 CGF.EmitCall(CGF.getTypes().arrangeFunctionCall(Args, DeleteFTy), 1467 CGF.CGM.GetAddrOfFunction(OperatorDelete), 1468 ReturnValueSlot(), Args, OperatorDelete); 1469 } 1470 }; 1471 } 1472 1473 /// Emit the code for deleting an array of objects. 1474 static void EmitArrayDelete(CodeGenFunction &CGF, 1475 const CXXDeleteExpr *E, 1476 llvm::Value *deletedPtr, 1477 QualType elementType) { 1478 llvm::Value *numElements = 0; 1479 llvm::Value *allocatedPtr = 0; 1480 CharUnits cookieSize; 1481 CGF.CGM.getCXXABI().ReadArrayCookie(CGF, deletedPtr, E, elementType, 1482 numElements, allocatedPtr, cookieSize); 1483 1484 assert(allocatedPtr && "ReadArrayCookie didn't set allocated pointer"); 1485 1486 // Make sure that we call delete even if one of the dtors throws. 1487 const FunctionDecl *operatorDelete = E->getOperatorDelete(); 1488 CGF.EHStack.pushCleanup<CallArrayDelete>(NormalAndEHCleanup, 1489 allocatedPtr, operatorDelete, 1490 numElements, elementType, 1491 cookieSize); 1492 1493 // Destroy the elements. 1494 if (QualType::DestructionKind dtorKind = elementType.isDestructedType()) { 1495 assert(numElements && "no element count for a type with a destructor!"); 1496 1497 llvm::Value *arrayEnd = 1498 CGF.Builder.CreateInBoundsGEP(deletedPtr, numElements, "delete.end"); 1499 1500 // Note that it is legal to allocate a zero-length array, and we 1501 // can never fold the check away because the length should always 1502 // come from a cookie. 1503 CGF.emitArrayDestroy(deletedPtr, arrayEnd, elementType, 1504 CGF.getDestroyer(dtorKind), 1505 /*checkZeroLength*/ true, 1506 CGF.needsEHCleanup(dtorKind)); 1507 } 1508 1509 // Pop the cleanup block. 1510 CGF.PopCleanupBlock(); 1511 } 1512 1513 void CodeGenFunction::EmitCXXDeleteExpr(const CXXDeleteExpr *E) { 1514 1515 // Get at the argument before we performed the implicit conversion 1516 // to void*. 1517 const Expr *Arg = E->getArgument(); 1518 while (const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(Arg)) { 1519 if (ICE->getCastKind() != CK_UserDefinedConversion && 1520 ICE->getType()->isVoidPointerType()) 1521 Arg = ICE->getSubExpr(); 1522 else 1523 break; 1524 } 1525 1526 llvm::Value *Ptr = EmitScalarExpr(Arg); 1527 1528 // Null check the pointer. 1529 llvm::BasicBlock *DeleteNotNull = createBasicBlock("delete.notnull"); 1530 llvm::BasicBlock *DeleteEnd = createBasicBlock("delete.end"); 1531 1532 llvm::Value *IsNull = Builder.CreateIsNull(Ptr, "isnull"); 1533 1534 Builder.CreateCondBr(IsNull, DeleteEnd, DeleteNotNull); 1535 EmitBlock(DeleteNotNull); 1536 1537 // We might be deleting a pointer to array. If so, GEP down to the 1538 // first non-array element. 1539 // (this assumes that A(*)[3][7] is converted to [3 x [7 x %A]]*) 1540 QualType DeleteTy = Arg->getType()->getAs<PointerType>()->getPointeeType(); 1541 if (DeleteTy->isConstantArrayType()) { 1542 llvm::Value *Zero = Builder.getInt32(0); 1543 SmallVector<llvm::Value*,8> GEP; 1544 1545 GEP.push_back(Zero); // point at the outermost array 1546 1547 // For each layer of array type we're pointing at: 1548 while (const ConstantArrayType *Arr 1549 = getContext().getAsConstantArrayType(DeleteTy)) { 1550 // 1. Unpeel the array type. 1551 DeleteTy = Arr->getElementType(); 1552 1553 // 2. GEP to the first element of the array. 1554 GEP.push_back(Zero); 1555 } 1556 1557 Ptr = Builder.CreateInBoundsGEP(Ptr, GEP, "del.first"); 1558 } 1559 1560 assert(ConvertTypeForMem(DeleteTy) == 1561 cast<llvm::PointerType>(Ptr->getType())->getElementType()); 1562 1563 if (E->isArrayForm()) { 1564 EmitArrayDelete(*this, E, Ptr, DeleteTy); 1565 } else { 1566 EmitObjectDelete(*this, E->getOperatorDelete(), Ptr, DeleteTy, 1567 E->isGlobalDelete()); 1568 } 1569 1570 EmitBlock(DeleteEnd); 1571 } 1572 1573 static llvm::Constant *getBadTypeidFn(CodeGenFunction &CGF) { 1574 // void __cxa_bad_typeid(); 1575 llvm::FunctionType *FTy = llvm::FunctionType::get(CGF.VoidTy, false); 1576 1577 return CGF.CGM.CreateRuntimeFunction(FTy, "__cxa_bad_typeid"); 1578 } 1579 1580 static void EmitBadTypeidCall(CodeGenFunction &CGF) { 1581 llvm::Value *Fn = getBadTypeidFn(CGF); 1582 CGF.EmitCallOrInvoke(Fn).setDoesNotReturn(); 1583 CGF.Builder.CreateUnreachable(); 1584 } 1585 1586 static llvm::Value *EmitTypeidFromVTable(CodeGenFunction &CGF, 1587 const Expr *E, 1588 llvm::Type *StdTypeInfoPtrTy) { 1589 // Get the vtable pointer. 1590 llvm::Value *ThisPtr = CGF.EmitLValue(E).getAddress(); 1591 1592 // C++ [expr.typeid]p2: 1593 // If the glvalue expression is obtained by applying the unary * operator to 1594 // a pointer and the pointer is a null pointer value, the typeid expression 1595 // throws the std::bad_typeid exception. 1596 if (const UnaryOperator *UO = dyn_cast<UnaryOperator>(E->IgnoreParens())) { 1597 if (UO->getOpcode() == UO_Deref) { 1598 llvm::BasicBlock *BadTypeidBlock = 1599 CGF.createBasicBlock("typeid.bad_typeid"); 1600 llvm::BasicBlock *EndBlock = 1601 CGF.createBasicBlock("typeid.end"); 1602 1603 llvm::Value *IsNull = CGF.Builder.CreateIsNull(ThisPtr); 1604 CGF.Builder.CreateCondBr(IsNull, BadTypeidBlock, EndBlock); 1605 1606 CGF.EmitBlock(BadTypeidBlock); 1607 EmitBadTypeidCall(CGF); 1608 CGF.EmitBlock(EndBlock); 1609 } 1610 } 1611 1612 llvm::Value *Value = CGF.GetVTablePtr(ThisPtr, 1613 StdTypeInfoPtrTy->getPointerTo()); 1614 1615 // Load the type info. 1616 Value = CGF.Builder.CreateConstInBoundsGEP1_64(Value, -1ULL); 1617 return CGF.Builder.CreateLoad(Value); 1618 } 1619 1620 llvm::Value *CodeGenFunction::EmitCXXTypeidExpr(const CXXTypeidExpr *E) { 1621 llvm::Type *StdTypeInfoPtrTy = 1622 ConvertType(E->getType())->getPointerTo(); 1623 1624 if (E->isTypeOperand()) { 1625 llvm::Constant *TypeInfo = 1626 CGM.GetAddrOfRTTIDescriptor(E->getTypeOperand()); 1627 return Builder.CreateBitCast(TypeInfo, StdTypeInfoPtrTy); 1628 } 1629 1630 // C++ [expr.typeid]p2: 1631 // When typeid is applied to a glvalue expression whose type is a 1632 // polymorphic class type, the result refers to a std::type_info object 1633 // representing the type of the most derived object (that is, the dynamic 1634 // type) to which the glvalue refers. 1635 if (E->getExprOperand()->isGLValue()) { 1636 if (const RecordType *RT = 1637 E->getExprOperand()->getType()->getAs<RecordType>()) { 1638 const CXXRecordDecl *RD = cast<CXXRecordDecl>(RT->getDecl()); 1639 if (RD->isPolymorphic()) 1640 return EmitTypeidFromVTable(*this, E->getExprOperand(), 1641 StdTypeInfoPtrTy); 1642 } 1643 } 1644 1645 QualType OperandTy = E->getExprOperand()->getType(); 1646 return Builder.CreateBitCast(CGM.GetAddrOfRTTIDescriptor(OperandTy), 1647 StdTypeInfoPtrTy); 1648 } 1649 1650 static llvm::Constant *getDynamicCastFn(CodeGenFunction &CGF) { 1651 // void *__dynamic_cast(const void *sub, 1652 // const abi::__class_type_info *src, 1653 // const abi::__class_type_info *dst, 1654 // std::ptrdiff_t src2dst_offset); 1655 1656 llvm::Type *Int8PtrTy = CGF.Int8PtrTy; 1657 llvm::Type *PtrDiffTy = 1658 CGF.ConvertType(CGF.getContext().getPointerDiffType()); 1659 1660 llvm::Type *Args[4] = { Int8PtrTy, Int8PtrTy, Int8PtrTy, PtrDiffTy }; 1661 1662 llvm::FunctionType *FTy = 1663 llvm::FunctionType::get(Int8PtrTy, Args, false); 1664 1665 return CGF.CGM.CreateRuntimeFunction(FTy, "__dynamic_cast"); 1666 } 1667 1668 static llvm::Constant *getBadCastFn(CodeGenFunction &CGF) { 1669 // void __cxa_bad_cast(); 1670 llvm::FunctionType *FTy = llvm::FunctionType::get(CGF.VoidTy, false); 1671 return CGF.CGM.CreateRuntimeFunction(FTy, "__cxa_bad_cast"); 1672 } 1673 1674 static void EmitBadCastCall(CodeGenFunction &CGF) { 1675 llvm::Value *Fn = getBadCastFn(CGF); 1676 CGF.EmitCallOrInvoke(Fn).setDoesNotReturn(); 1677 CGF.Builder.CreateUnreachable(); 1678 } 1679 1680 static llvm::Value * 1681 EmitDynamicCastCall(CodeGenFunction &CGF, llvm::Value *Value, 1682 QualType SrcTy, QualType DestTy, 1683 llvm::BasicBlock *CastEnd) { 1684 llvm::Type *PtrDiffLTy = 1685 CGF.ConvertType(CGF.getContext().getPointerDiffType()); 1686 llvm::Type *DestLTy = CGF.ConvertType(DestTy); 1687 1688 if (const PointerType *PTy = DestTy->getAs<PointerType>()) { 1689 if (PTy->getPointeeType()->isVoidType()) { 1690 // C++ [expr.dynamic.cast]p7: 1691 // If T is "pointer to cv void," then the result is a pointer to the 1692 // most derived object pointed to by v. 1693 1694 // Get the vtable pointer. 1695 llvm::Value *VTable = CGF.GetVTablePtr(Value, PtrDiffLTy->getPointerTo()); 1696 1697 // Get the offset-to-top from the vtable. 1698 llvm::Value *OffsetToTop = 1699 CGF.Builder.CreateConstInBoundsGEP1_64(VTable, -2ULL); 1700 OffsetToTop = CGF.Builder.CreateLoad(OffsetToTop, "offset.to.top"); 1701 1702 // Finally, add the offset to the pointer. 1703 Value = CGF.EmitCastToVoidPtr(Value); 1704 Value = CGF.Builder.CreateInBoundsGEP(Value, OffsetToTop); 1705 1706 return CGF.Builder.CreateBitCast(Value, DestLTy); 1707 } 1708 } 1709 1710 QualType SrcRecordTy; 1711 QualType DestRecordTy; 1712 1713 if (const PointerType *DestPTy = DestTy->getAs<PointerType>()) { 1714 SrcRecordTy = SrcTy->castAs<PointerType>()->getPointeeType(); 1715 DestRecordTy = DestPTy->getPointeeType(); 1716 } else { 1717 SrcRecordTy = SrcTy; 1718 DestRecordTy = DestTy->castAs<ReferenceType>()->getPointeeType(); 1719 } 1720 1721 assert(SrcRecordTy->isRecordType() && "source type must be a record type!"); 1722 assert(DestRecordTy->isRecordType() && "dest type must be a record type!"); 1723 1724 llvm::Value *SrcRTTI = 1725 CGF.CGM.GetAddrOfRTTIDescriptor(SrcRecordTy.getUnqualifiedType()); 1726 llvm::Value *DestRTTI = 1727 CGF.CGM.GetAddrOfRTTIDescriptor(DestRecordTy.getUnqualifiedType()); 1728 1729 // FIXME: Actually compute a hint here. 1730 llvm::Value *OffsetHint = llvm::ConstantInt::get(PtrDiffLTy, -1ULL); 1731 1732 // Emit the call to __dynamic_cast. 1733 Value = CGF.EmitCastToVoidPtr(Value); 1734 Value = CGF.Builder.CreateCall4(getDynamicCastFn(CGF), Value, 1735 SrcRTTI, DestRTTI, OffsetHint); 1736 Value = CGF.Builder.CreateBitCast(Value, DestLTy); 1737 1738 /// C++ [expr.dynamic.cast]p9: 1739 /// A failed cast to reference type throws std::bad_cast 1740 if (DestTy->isReferenceType()) { 1741 llvm::BasicBlock *BadCastBlock = 1742 CGF.createBasicBlock("dynamic_cast.bad_cast"); 1743 1744 llvm::Value *IsNull = CGF.Builder.CreateIsNull(Value); 1745 CGF.Builder.CreateCondBr(IsNull, BadCastBlock, CastEnd); 1746 1747 CGF.EmitBlock(BadCastBlock); 1748 EmitBadCastCall(CGF); 1749 } 1750 1751 return Value; 1752 } 1753 1754 static llvm::Value *EmitDynamicCastToNull(CodeGenFunction &CGF, 1755 QualType DestTy) { 1756 llvm::Type *DestLTy = CGF.ConvertType(DestTy); 1757 if (DestTy->isPointerType()) 1758 return llvm::Constant::getNullValue(DestLTy); 1759 1760 /// C++ [expr.dynamic.cast]p9: 1761 /// A failed cast to reference type throws std::bad_cast 1762 EmitBadCastCall(CGF); 1763 1764 CGF.EmitBlock(CGF.createBasicBlock("dynamic_cast.end")); 1765 return llvm::UndefValue::get(DestLTy); 1766 } 1767 1768 llvm::Value *CodeGenFunction::EmitDynamicCast(llvm::Value *Value, 1769 const CXXDynamicCastExpr *DCE) { 1770 QualType DestTy = DCE->getTypeAsWritten(); 1771 1772 if (DCE->isAlwaysNull()) 1773 return EmitDynamicCastToNull(*this, DestTy); 1774 1775 QualType SrcTy = DCE->getSubExpr()->getType(); 1776 1777 // C++ [expr.dynamic.cast]p4: 1778 // If the value of v is a null pointer value in the pointer case, the result 1779 // is the null pointer value of type T. 1780 bool ShouldNullCheckSrcValue = SrcTy->isPointerType(); 1781 1782 llvm::BasicBlock *CastNull = 0; 1783 llvm::BasicBlock *CastNotNull = 0; 1784 llvm::BasicBlock *CastEnd = createBasicBlock("dynamic_cast.end"); 1785 1786 if (ShouldNullCheckSrcValue) { 1787 CastNull = createBasicBlock("dynamic_cast.null"); 1788 CastNotNull = createBasicBlock("dynamic_cast.notnull"); 1789 1790 llvm::Value *IsNull = Builder.CreateIsNull(Value); 1791 Builder.CreateCondBr(IsNull, CastNull, CastNotNull); 1792 EmitBlock(CastNotNull); 1793 } 1794 1795 Value = EmitDynamicCastCall(*this, Value, SrcTy, DestTy, CastEnd); 1796 1797 if (ShouldNullCheckSrcValue) { 1798 EmitBranch(CastEnd); 1799 1800 EmitBlock(CastNull); 1801 EmitBranch(CastEnd); 1802 } 1803 1804 EmitBlock(CastEnd); 1805 1806 if (ShouldNullCheckSrcValue) { 1807 llvm::PHINode *PHI = Builder.CreatePHI(Value->getType(), 2); 1808 PHI->addIncoming(Value, CastNotNull); 1809 PHI->addIncoming(llvm::Constant::getNullValue(Value->getType()), CastNull); 1810 1811 Value = PHI; 1812 } 1813 1814 return Value; 1815 } 1816 1817 void CodeGenFunction::EmitLambdaExpr(const LambdaExpr *E, AggValueSlot Slot) { 1818 RunCleanupsScope Scope(*this); 1819 1820 CXXRecordDecl::field_iterator CurField = E->getLambdaClass()->field_begin(); 1821 for (LambdaExpr::capture_init_iterator i = E->capture_init_begin(), 1822 e = E->capture_init_end(); 1823 i != e; ++i, ++CurField) { 1824 // Emit initialization 1825 LValue LV = EmitLValueForFieldInitialization(Slot.getAddr(), *CurField, 0); 1826 ArrayRef<VarDecl *> ArrayIndexes; 1827 if (CurField->getType()->isArrayType()) 1828 ArrayIndexes = E->getCaptureInitIndexVars(i); 1829 EmitInitializerForField(*CurField, LV, *i, ArrayIndexes); 1830 } 1831 } 1832