1 //===--- CGExprCXX.cpp - Emit LLVM Code for C++ expressions ---------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This contains code dealing with code generation of C++ expressions
10 //
11 //===----------------------------------------------------------------------===//
12
13 #include "CGCUDARuntime.h"
14 #include "CGCXXABI.h"
15 #include "CGDebugInfo.h"
16 #include "CGObjCRuntime.h"
17 #include "CodeGenFunction.h"
18 #include "ConstantEmitter.h"
19 #include "TargetInfo.h"
20 #include "clang/Basic/CodeGenOptions.h"
21 #include "clang/CodeGen/CGFunctionInfo.h"
22 #include "llvm/IR/Intrinsics.h"
23
24 using namespace clang;
25 using namespace CodeGen;
26
27 namespace {
28 struct MemberCallInfo {
29 RequiredArgs ReqArgs;
30 // Number of prefix arguments for the call. Ignores the `this` pointer.
31 unsigned PrefixSize;
32 };
33 }
34
35 static MemberCallInfo
commonEmitCXXMemberOrOperatorCall(CodeGenFunction & CGF,const CXXMethodDecl * MD,llvm::Value * This,llvm::Value * ImplicitParam,QualType ImplicitParamTy,const CallExpr * CE,CallArgList & Args,CallArgList * RtlArgs)36 commonEmitCXXMemberOrOperatorCall(CodeGenFunction &CGF, const CXXMethodDecl *MD,
37 llvm::Value *This, llvm::Value *ImplicitParam,
38 QualType ImplicitParamTy, const CallExpr *CE,
39 CallArgList &Args, CallArgList *RtlArgs) {
40 assert(CE == nullptr || isa<CXXMemberCallExpr>(CE) ||
41 isa<CXXOperatorCallExpr>(CE));
42 assert(MD->isInstance() &&
43 "Trying to emit a member or operator call expr on a static method!");
44
45 // Push the this ptr.
46 const CXXRecordDecl *RD =
47 CGF.CGM.getCXXABI().getThisArgumentTypeForMethod(MD);
48 Args.add(RValue::get(This), CGF.getTypes().DeriveThisType(RD, MD));
49
50 // If there is an implicit parameter (e.g. VTT), emit it.
51 if (ImplicitParam) {
52 Args.add(RValue::get(ImplicitParam), ImplicitParamTy);
53 }
54
55 const FunctionProtoType *FPT = MD->getType()->castAs<FunctionProtoType>();
56 RequiredArgs required = RequiredArgs::forPrototypePlus(FPT, Args.size());
57 unsigned PrefixSize = Args.size() - 1;
58
59 // And the rest of the call args.
60 if (RtlArgs) {
61 // Special case: if the caller emitted the arguments right-to-left already
62 // (prior to emitting the *this argument), we're done. This happens for
63 // assignment operators.
64 Args.addFrom(*RtlArgs);
65 } else if (CE) {
66 // Special case: skip first argument of CXXOperatorCall (it is "this").
67 unsigned ArgsToSkip = isa<CXXOperatorCallExpr>(CE) ? 1 : 0;
68 CGF.EmitCallArgs(Args, FPT, drop_begin(CE->arguments(), ArgsToSkip),
69 CE->getDirectCallee());
70 } else {
71 assert(
72 FPT->getNumParams() == 0 &&
73 "No CallExpr specified for function with non-zero number of arguments");
74 }
75 return {required, PrefixSize};
76 }
77
EmitCXXMemberOrOperatorCall(const CXXMethodDecl * MD,const CGCallee & Callee,ReturnValueSlot ReturnValue,llvm::Value * This,llvm::Value * ImplicitParam,QualType ImplicitParamTy,const CallExpr * CE,CallArgList * RtlArgs)78 RValue CodeGenFunction::EmitCXXMemberOrOperatorCall(
79 const CXXMethodDecl *MD, const CGCallee &Callee,
80 ReturnValueSlot ReturnValue,
81 llvm::Value *This, llvm::Value *ImplicitParam, QualType ImplicitParamTy,
82 const CallExpr *CE, CallArgList *RtlArgs) {
83 const FunctionProtoType *FPT = MD->getType()->castAs<FunctionProtoType>();
84 CallArgList Args;
85 MemberCallInfo CallInfo = commonEmitCXXMemberOrOperatorCall(
86 *this, MD, This, ImplicitParam, ImplicitParamTy, CE, Args, RtlArgs);
87 auto &FnInfo = CGM.getTypes().arrangeCXXMethodCall(
88 Args, FPT, CallInfo.ReqArgs, CallInfo.PrefixSize);
89 return EmitCall(FnInfo, Callee, ReturnValue, Args, nullptr,
90 CE ? CE->getExprLoc() : SourceLocation());
91 }
92
EmitCXXDestructorCall(GlobalDecl Dtor,const CGCallee & Callee,llvm::Value * This,QualType ThisTy,llvm::Value * ImplicitParam,QualType ImplicitParamTy,const CallExpr * CE)93 RValue CodeGenFunction::EmitCXXDestructorCall(
94 GlobalDecl Dtor, const CGCallee &Callee, llvm::Value *This, QualType ThisTy,
95 llvm::Value *ImplicitParam, QualType ImplicitParamTy, const CallExpr *CE) {
96 const CXXMethodDecl *DtorDecl = cast<CXXMethodDecl>(Dtor.getDecl());
97
98 assert(!ThisTy.isNull());
99 assert(ThisTy->getAsCXXRecordDecl() == DtorDecl->getParent() &&
100 "Pointer/Object mixup");
101
102 LangAS SrcAS = ThisTy.getAddressSpace();
103 LangAS DstAS = DtorDecl->getMethodQualifiers().getAddressSpace();
104 if (SrcAS != DstAS) {
105 QualType DstTy = DtorDecl->getThisType();
106 llvm::Type *NewType = CGM.getTypes().ConvertType(DstTy);
107 This = getTargetHooks().performAddrSpaceCast(*this, This, SrcAS, DstAS,
108 NewType);
109 }
110
111 CallArgList Args;
112 commonEmitCXXMemberOrOperatorCall(*this, DtorDecl, This, ImplicitParam,
113 ImplicitParamTy, CE, Args, nullptr);
114 return EmitCall(CGM.getTypes().arrangeCXXStructorDeclaration(Dtor), Callee,
115 ReturnValueSlot(), Args);
116 }
117
EmitCXXPseudoDestructorExpr(const CXXPseudoDestructorExpr * E)118 RValue CodeGenFunction::EmitCXXPseudoDestructorExpr(
119 const CXXPseudoDestructorExpr *E) {
120 QualType DestroyedType = E->getDestroyedType();
121 if (DestroyedType.hasStrongOrWeakObjCLifetime()) {
122 // Automatic Reference Counting:
123 // If the pseudo-expression names a retainable object with weak or
124 // strong lifetime, the object shall be released.
125 Expr *BaseExpr = E->getBase();
126 Address BaseValue = Address::invalid();
127 Qualifiers BaseQuals;
128
129 // If this is s.x, emit s as an lvalue. If it is s->x, emit s as a scalar.
130 if (E->isArrow()) {
131 BaseValue = EmitPointerWithAlignment(BaseExpr);
132 const auto *PTy = BaseExpr->getType()->castAs<PointerType>();
133 BaseQuals = PTy->getPointeeType().getQualifiers();
134 } else {
135 LValue BaseLV = EmitLValue(BaseExpr);
136 BaseValue = BaseLV.getAddress(*this);
137 QualType BaseTy = BaseExpr->getType();
138 BaseQuals = BaseTy.getQualifiers();
139 }
140
141 switch (DestroyedType.getObjCLifetime()) {
142 case Qualifiers::OCL_None:
143 case Qualifiers::OCL_ExplicitNone:
144 case Qualifiers::OCL_Autoreleasing:
145 break;
146
147 case Qualifiers::OCL_Strong:
148 EmitARCRelease(Builder.CreateLoad(BaseValue,
149 DestroyedType.isVolatileQualified()),
150 ARCPreciseLifetime);
151 break;
152
153 case Qualifiers::OCL_Weak:
154 EmitARCDestroyWeak(BaseValue);
155 break;
156 }
157 } else {
158 // C++ [expr.pseudo]p1:
159 // The result shall only be used as the operand for the function call
160 // operator (), and the result of such a call has type void. The only
161 // effect is the evaluation of the postfix-expression before the dot or
162 // arrow.
163 EmitIgnoredExpr(E->getBase());
164 }
165
166 return RValue::get(nullptr);
167 }
168
getCXXRecord(const Expr * E)169 static CXXRecordDecl *getCXXRecord(const Expr *E) {
170 QualType T = E->getType();
171 if (const PointerType *PTy = T->getAs<PointerType>())
172 T = PTy->getPointeeType();
173 const RecordType *Ty = T->castAs<RecordType>();
174 return cast<CXXRecordDecl>(Ty->getDecl());
175 }
176
177 // Note: This function also emit constructor calls to support a MSVC
178 // extensions allowing explicit constructor function call.
EmitCXXMemberCallExpr(const CXXMemberCallExpr * CE,ReturnValueSlot ReturnValue)179 RValue CodeGenFunction::EmitCXXMemberCallExpr(const CXXMemberCallExpr *CE,
180 ReturnValueSlot ReturnValue) {
181 const Expr *callee = CE->getCallee()->IgnoreParens();
182
183 if (isa<BinaryOperator>(callee))
184 return EmitCXXMemberPointerCallExpr(CE, ReturnValue);
185
186 const MemberExpr *ME = cast<MemberExpr>(callee);
187 const CXXMethodDecl *MD = cast<CXXMethodDecl>(ME->getMemberDecl());
188
189 if (MD->isStatic()) {
190 // The method is static, emit it as we would a regular call.
191 CGCallee callee =
192 CGCallee::forDirect(CGM.GetAddrOfFunction(MD), GlobalDecl(MD));
193 return EmitCall(getContext().getPointerType(MD->getType()), callee, CE,
194 ReturnValue);
195 }
196
197 bool HasQualifier = ME->hasQualifier();
198 NestedNameSpecifier *Qualifier = HasQualifier ? ME->getQualifier() : nullptr;
199 bool IsArrow = ME->isArrow();
200 const Expr *Base = ME->getBase();
201
202 return EmitCXXMemberOrOperatorMemberCallExpr(
203 CE, MD, ReturnValue, HasQualifier, Qualifier, IsArrow, Base);
204 }
205
EmitCXXMemberOrOperatorMemberCallExpr(const CallExpr * CE,const CXXMethodDecl * MD,ReturnValueSlot ReturnValue,bool HasQualifier,NestedNameSpecifier * Qualifier,bool IsArrow,const Expr * Base)206 RValue CodeGenFunction::EmitCXXMemberOrOperatorMemberCallExpr(
207 const CallExpr *CE, const CXXMethodDecl *MD, ReturnValueSlot ReturnValue,
208 bool HasQualifier, NestedNameSpecifier *Qualifier, bool IsArrow,
209 const Expr *Base) {
210 assert(isa<CXXMemberCallExpr>(CE) || isa<CXXOperatorCallExpr>(CE));
211
212 // Compute the object pointer.
213 bool CanUseVirtualCall = MD->isVirtual() && !HasQualifier;
214
215 const CXXMethodDecl *DevirtualizedMethod = nullptr;
216 if (CanUseVirtualCall &&
217 MD->getDevirtualizedMethod(Base, getLangOpts().AppleKext)) {
218 const CXXRecordDecl *BestDynamicDecl = Base->getBestDynamicClassType();
219 DevirtualizedMethod = MD->getCorrespondingMethodInClass(BestDynamicDecl);
220 assert(DevirtualizedMethod);
221 const CXXRecordDecl *DevirtualizedClass = DevirtualizedMethod->getParent();
222 const Expr *Inner = Base->ignoreParenBaseCasts();
223 if (DevirtualizedMethod->getReturnType().getCanonicalType() !=
224 MD->getReturnType().getCanonicalType())
225 // If the return types are not the same, this might be a case where more
226 // code needs to run to compensate for it. For example, the derived
227 // method might return a type that inherits form from the return
228 // type of MD and has a prefix.
229 // For now we just avoid devirtualizing these covariant cases.
230 DevirtualizedMethod = nullptr;
231 else if (getCXXRecord(Inner) == DevirtualizedClass)
232 // If the class of the Inner expression is where the dynamic method
233 // is defined, build the this pointer from it.
234 Base = Inner;
235 else if (getCXXRecord(Base) != DevirtualizedClass) {
236 // If the method is defined in a class that is not the best dynamic
237 // one or the one of the full expression, we would have to build
238 // a derived-to-base cast to compute the correct this pointer, but
239 // we don't have support for that yet, so do a virtual call.
240 DevirtualizedMethod = nullptr;
241 }
242 }
243
244 bool TrivialForCodegen =
245 MD->isTrivial() || (MD->isDefaulted() && MD->getParent()->isUnion());
246 bool TrivialAssignment =
247 TrivialForCodegen &&
248 (MD->isCopyAssignmentOperator() || MD->isMoveAssignmentOperator()) &&
249 !MD->getParent()->mayInsertExtraPadding();
250
251 // C++17 demands that we evaluate the RHS of a (possibly-compound) assignment
252 // operator before the LHS.
253 CallArgList RtlArgStorage;
254 CallArgList *RtlArgs = nullptr;
255 LValue TrivialAssignmentRHS;
256 if (auto *OCE = dyn_cast<CXXOperatorCallExpr>(CE)) {
257 if (OCE->isAssignmentOp()) {
258 if (TrivialAssignment) {
259 TrivialAssignmentRHS = EmitLValue(CE->getArg(1));
260 } else {
261 RtlArgs = &RtlArgStorage;
262 EmitCallArgs(*RtlArgs, MD->getType()->castAs<FunctionProtoType>(),
263 drop_begin(CE->arguments(), 1), CE->getDirectCallee(),
264 /*ParamsToSkip*/0, EvaluationOrder::ForceRightToLeft);
265 }
266 }
267 }
268
269 LValue This;
270 if (IsArrow) {
271 LValueBaseInfo BaseInfo;
272 TBAAAccessInfo TBAAInfo;
273 Address ThisValue = EmitPointerWithAlignment(Base, &BaseInfo, &TBAAInfo);
274 This = MakeAddrLValue(ThisValue, Base->getType(), BaseInfo, TBAAInfo);
275 } else {
276 This = EmitLValue(Base);
277 }
278
279 if (const CXXConstructorDecl *Ctor = dyn_cast<CXXConstructorDecl>(MD)) {
280 // This is the MSVC p->Ctor::Ctor(...) extension. We assume that's
281 // constructing a new complete object of type Ctor.
282 assert(!RtlArgs);
283 assert(ReturnValue.isNull() && "Constructor shouldn't have return value");
284 CallArgList Args;
285 commonEmitCXXMemberOrOperatorCall(
286 *this, Ctor, This.getPointer(*this), /*ImplicitParam=*/nullptr,
287 /*ImplicitParamTy=*/QualType(), CE, Args, nullptr);
288
289 EmitCXXConstructorCall(Ctor, Ctor_Complete, /*ForVirtualBase=*/false,
290 /*Delegating=*/false, This.getAddress(*this), Args,
291 AggValueSlot::DoesNotOverlap, CE->getExprLoc(),
292 /*NewPointerIsChecked=*/false);
293 return RValue::get(nullptr);
294 }
295
296 if (TrivialForCodegen) {
297 if (isa<CXXDestructorDecl>(MD))
298 return RValue::get(nullptr);
299
300 if (TrivialAssignment) {
301 // We don't like to generate the trivial copy/move assignment operator
302 // when it isn't necessary; just produce the proper effect here.
303 // It's important that we use the result of EmitLValue here rather than
304 // emitting call arguments, in order to preserve TBAA information from
305 // the RHS.
306 LValue RHS = isa<CXXOperatorCallExpr>(CE)
307 ? TrivialAssignmentRHS
308 : EmitLValue(*CE->arg_begin());
309 EmitAggregateAssign(This, RHS, CE->getType());
310 return RValue::get(This.getPointer(*this));
311 }
312
313 assert(MD->getParent()->mayInsertExtraPadding() &&
314 "unknown trivial member function");
315 }
316
317 // Compute the function type we're calling.
318 const CXXMethodDecl *CalleeDecl =
319 DevirtualizedMethod ? DevirtualizedMethod : MD;
320 const CGFunctionInfo *FInfo = nullptr;
321 if (const auto *Dtor = dyn_cast<CXXDestructorDecl>(CalleeDecl))
322 FInfo = &CGM.getTypes().arrangeCXXStructorDeclaration(
323 GlobalDecl(Dtor, Dtor_Complete));
324 else
325 FInfo = &CGM.getTypes().arrangeCXXMethodDeclaration(CalleeDecl);
326
327 llvm::FunctionType *Ty = CGM.getTypes().GetFunctionType(*FInfo);
328
329 // C++11 [class.mfct.non-static]p2:
330 // If a non-static member function of a class X is called for an object that
331 // is not of type X, or of a type derived from X, the behavior is undefined.
332 SourceLocation CallLoc;
333 ASTContext &C = getContext();
334 if (CE)
335 CallLoc = CE->getExprLoc();
336
337 SanitizerSet SkippedChecks;
338 if (const auto *CMCE = dyn_cast<CXXMemberCallExpr>(CE)) {
339 auto *IOA = CMCE->getImplicitObjectArgument();
340 bool IsImplicitObjectCXXThis = IsWrappedCXXThis(IOA);
341 if (IsImplicitObjectCXXThis)
342 SkippedChecks.set(SanitizerKind::Alignment, true);
343 if (IsImplicitObjectCXXThis || isa<DeclRefExpr>(IOA))
344 SkippedChecks.set(SanitizerKind::Null, true);
345 }
346 EmitTypeCheck(CodeGenFunction::TCK_MemberCall, CallLoc,
347 This.getPointer(*this),
348 C.getRecordType(CalleeDecl->getParent()),
349 /*Alignment=*/CharUnits::Zero(), SkippedChecks);
350
351 // C++ [class.virtual]p12:
352 // Explicit qualification with the scope operator (5.1) suppresses the
353 // virtual call mechanism.
354 //
355 // We also don't emit a virtual call if the base expression has a record type
356 // because then we know what the type is.
357 bool UseVirtualCall = CanUseVirtualCall && !DevirtualizedMethod;
358
359 if (const CXXDestructorDecl *Dtor = dyn_cast<CXXDestructorDecl>(CalleeDecl)) {
360 assert(CE->arg_begin() == CE->arg_end() &&
361 "Destructor shouldn't have explicit parameters");
362 assert(ReturnValue.isNull() && "Destructor shouldn't have return value");
363 if (UseVirtualCall) {
364 CGM.getCXXABI().EmitVirtualDestructorCall(*this, Dtor, Dtor_Complete,
365 This.getAddress(*this),
366 cast<CXXMemberCallExpr>(CE));
367 } else {
368 GlobalDecl GD(Dtor, Dtor_Complete);
369 CGCallee Callee;
370 if (getLangOpts().AppleKext && Dtor->isVirtual() && HasQualifier)
371 Callee = BuildAppleKextVirtualCall(Dtor, Qualifier, Ty);
372 else if (!DevirtualizedMethod)
373 Callee =
374 CGCallee::forDirect(CGM.getAddrOfCXXStructor(GD, FInfo, Ty), GD);
375 else {
376 Callee = CGCallee::forDirect(CGM.GetAddrOfFunction(GD, Ty), GD);
377 }
378
379 QualType ThisTy =
380 IsArrow ? Base->getType()->getPointeeType() : Base->getType();
381 EmitCXXDestructorCall(GD, Callee, This.getPointer(*this), ThisTy,
382 /*ImplicitParam=*/nullptr,
383 /*ImplicitParamTy=*/QualType(), nullptr);
384 }
385 return RValue::get(nullptr);
386 }
387
388 // FIXME: Uses of 'MD' past this point need to be audited. We may need to use
389 // 'CalleeDecl' instead.
390
391 CGCallee Callee;
392 if (UseVirtualCall) {
393 Callee = CGCallee::forVirtual(CE, MD, This.getAddress(*this), Ty);
394 } else {
395 if (SanOpts.has(SanitizerKind::CFINVCall) &&
396 MD->getParent()->isDynamicClass()) {
397 llvm::Value *VTable;
398 const CXXRecordDecl *RD;
399 std::tie(VTable, RD) = CGM.getCXXABI().LoadVTablePtr(
400 *this, This.getAddress(*this), CalleeDecl->getParent());
401 EmitVTablePtrCheckForCall(RD, VTable, CFITCK_NVCall, CE->getBeginLoc());
402 }
403
404 if (getLangOpts().AppleKext && MD->isVirtual() && HasQualifier)
405 Callee = BuildAppleKextVirtualCall(MD, Qualifier, Ty);
406 else if (!DevirtualizedMethod)
407 Callee =
408 CGCallee::forDirect(CGM.GetAddrOfFunction(MD, Ty), GlobalDecl(MD));
409 else {
410 Callee =
411 CGCallee::forDirect(CGM.GetAddrOfFunction(DevirtualizedMethod, Ty),
412 GlobalDecl(DevirtualizedMethod));
413 }
414 }
415
416 if (MD->isVirtual()) {
417 Address NewThisAddr =
418 CGM.getCXXABI().adjustThisArgumentForVirtualFunctionCall(
419 *this, CalleeDecl, This.getAddress(*this), UseVirtualCall);
420 This.setAddress(NewThisAddr);
421 }
422
423 return EmitCXXMemberOrOperatorCall(
424 CalleeDecl, Callee, ReturnValue, This.getPointer(*this),
425 /*ImplicitParam=*/nullptr, QualType(), CE, RtlArgs);
426 }
427
428 RValue
EmitCXXMemberPointerCallExpr(const CXXMemberCallExpr * E,ReturnValueSlot ReturnValue)429 CodeGenFunction::EmitCXXMemberPointerCallExpr(const CXXMemberCallExpr *E,
430 ReturnValueSlot ReturnValue) {
431 const BinaryOperator *BO =
432 cast<BinaryOperator>(E->getCallee()->IgnoreParens());
433 const Expr *BaseExpr = BO->getLHS();
434 const Expr *MemFnExpr = BO->getRHS();
435
436 const auto *MPT = MemFnExpr->getType()->castAs<MemberPointerType>();
437 const auto *FPT = MPT->getPointeeType()->castAs<FunctionProtoType>();
438 const auto *RD =
439 cast<CXXRecordDecl>(MPT->getClass()->castAs<RecordType>()->getDecl());
440
441 // Emit the 'this' pointer.
442 Address This = Address::invalid();
443 if (BO->getOpcode() == BO_PtrMemI)
444 This = EmitPointerWithAlignment(BaseExpr);
445 else
446 This = EmitLValue(BaseExpr).getAddress(*this);
447
448 EmitTypeCheck(TCK_MemberCall, E->getExprLoc(), This.getPointer(),
449 QualType(MPT->getClass(), 0));
450
451 // Get the member function pointer.
452 llvm::Value *MemFnPtr = EmitScalarExpr(MemFnExpr);
453
454 // Ask the ABI to load the callee. Note that This is modified.
455 llvm::Value *ThisPtrForCall = nullptr;
456 CGCallee Callee =
457 CGM.getCXXABI().EmitLoadOfMemberFunctionPointer(*this, BO, This,
458 ThisPtrForCall, MemFnPtr, MPT);
459
460 CallArgList Args;
461
462 QualType ThisType =
463 getContext().getPointerType(getContext().getTagDeclType(RD));
464
465 // Push the this ptr.
466 Args.add(RValue::get(ThisPtrForCall), ThisType);
467
468 RequiredArgs required = RequiredArgs::forPrototypePlus(FPT, 1);
469
470 // And the rest of the call args
471 EmitCallArgs(Args, FPT, E->arguments());
472 return EmitCall(CGM.getTypes().arrangeCXXMethodCall(Args, FPT, required,
473 /*PrefixSize=*/0),
474 Callee, ReturnValue, Args, nullptr, E->getExprLoc());
475 }
476
477 RValue
EmitCXXOperatorMemberCallExpr(const CXXOperatorCallExpr * E,const CXXMethodDecl * MD,ReturnValueSlot ReturnValue)478 CodeGenFunction::EmitCXXOperatorMemberCallExpr(const CXXOperatorCallExpr *E,
479 const CXXMethodDecl *MD,
480 ReturnValueSlot ReturnValue) {
481 assert(MD->isInstance() &&
482 "Trying to emit a member call expr on a static method!");
483 return EmitCXXMemberOrOperatorMemberCallExpr(
484 E, MD, ReturnValue, /*HasQualifier=*/false, /*Qualifier=*/nullptr,
485 /*IsArrow=*/false, E->getArg(0));
486 }
487
EmitCUDAKernelCallExpr(const CUDAKernelCallExpr * E,ReturnValueSlot ReturnValue)488 RValue CodeGenFunction::EmitCUDAKernelCallExpr(const CUDAKernelCallExpr *E,
489 ReturnValueSlot ReturnValue) {
490 return CGM.getCUDARuntime().EmitCUDAKernelCallExpr(*this, E, ReturnValue);
491 }
492
EmitNullBaseClassInitialization(CodeGenFunction & CGF,Address DestPtr,const CXXRecordDecl * Base)493 static void EmitNullBaseClassInitialization(CodeGenFunction &CGF,
494 Address DestPtr,
495 const CXXRecordDecl *Base) {
496 if (Base->isEmpty())
497 return;
498
499 DestPtr = CGF.Builder.CreateElementBitCast(DestPtr, CGF.Int8Ty);
500
501 const ASTRecordLayout &Layout = CGF.getContext().getASTRecordLayout(Base);
502 CharUnits NVSize = Layout.getNonVirtualSize();
503
504 // We cannot simply zero-initialize the entire base sub-object if vbptrs are
505 // present, they are initialized by the most derived class before calling the
506 // constructor.
507 SmallVector<std::pair<CharUnits, CharUnits>, 1> Stores;
508 Stores.emplace_back(CharUnits::Zero(), NVSize);
509
510 // Each store is split by the existence of a vbptr.
511 CharUnits VBPtrWidth = CGF.getPointerSize();
512 std::vector<CharUnits> VBPtrOffsets =
513 CGF.CGM.getCXXABI().getVBPtrOffsets(Base);
514 for (CharUnits VBPtrOffset : VBPtrOffsets) {
515 // Stop before we hit any virtual base pointers located in virtual bases.
516 if (VBPtrOffset >= NVSize)
517 break;
518 std::pair<CharUnits, CharUnits> LastStore = Stores.pop_back_val();
519 CharUnits LastStoreOffset = LastStore.first;
520 CharUnits LastStoreSize = LastStore.second;
521
522 CharUnits SplitBeforeOffset = LastStoreOffset;
523 CharUnits SplitBeforeSize = VBPtrOffset - SplitBeforeOffset;
524 assert(!SplitBeforeSize.isNegative() && "negative store size!");
525 if (!SplitBeforeSize.isZero())
526 Stores.emplace_back(SplitBeforeOffset, SplitBeforeSize);
527
528 CharUnits SplitAfterOffset = VBPtrOffset + VBPtrWidth;
529 CharUnits SplitAfterSize = LastStoreSize - SplitAfterOffset;
530 assert(!SplitAfterSize.isNegative() && "negative store size!");
531 if (!SplitAfterSize.isZero())
532 Stores.emplace_back(SplitAfterOffset, SplitAfterSize);
533 }
534
535 // If the type contains a pointer to data member we can't memset it to zero.
536 // Instead, create a null constant and copy it to the destination.
537 // TODO: there are other patterns besides zero that we can usefully memset,
538 // like -1, which happens to be the pattern used by member-pointers.
539 // TODO: isZeroInitializable can be over-conservative in the case where a
540 // virtual base contains a member pointer.
541 llvm::Constant *NullConstantForBase = CGF.CGM.EmitNullConstantForBase(Base);
542 if (!NullConstantForBase->isNullValue()) {
543 llvm::GlobalVariable *NullVariable = new llvm::GlobalVariable(
544 CGF.CGM.getModule(), NullConstantForBase->getType(),
545 /*isConstant=*/true, llvm::GlobalVariable::PrivateLinkage,
546 NullConstantForBase, Twine());
547
548 CharUnits Align = std::max(Layout.getNonVirtualAlignment(),
549 DestPtr.getAlignment());
550 NullVariable->setAlignment(Align.getAsAlign());
551
552 Address SrcPtr = Address(CGF.EmitCastToVoidPtr(NullVariable), Align);
553
554 // Get and call the appropriate llvm.memcpy overload.
555 for (std::pair<CharUnits, CharUnits> Store : Stores) {
556 CharUnits StoreOffset = Store.first;
557 CharUnits StoreSize = Store.second;
558 llvm::Value *StoreSizeVal = CGF.CGM.getSize(StoreSize);
559 CGF.Builder.CreateMemCpy(
560 CGF.Builder.CreateConstInBoundsByteGEP(DestPtr, StoreOffset),
561 CGF.Builder.CreateConstInBoundsByteGEP(SrcPtr, StoreOffset),
562 StoreSizeVal);
563 }
564
565 // Otherwise, just memset the whole thing to zero. This is legal
566 // because in LLVM, all default initializers (other than the ones we just
567 // handled above) are guaranteed to have a bit pattern of all zeros.
568 } else {
569 for (std::pair<CharUnits, CharUnits> Store : Stores) {
570 CharUnits StoreOffset = Store.first;
571 CharUnits StoreSize = Store.second;
572 llvm::Value *StoreSizeVal = CGF.CGM.getSize(StoreSize);
573 CGF.Builder.CreateMemSet(
574 CGF.Builder.CreateConstInBoundsByteGEP(DestPtr, StoreOffset),
575 CGF.Builder.getInt8(0), StoreSizeVal);
576 }
577 }
578 }
579
580 void
EmitCXXConstructExpr(const CXXConstructExpr * E,AggValueSlot Dest)581 CodeGenFunction::EmitCXXConstructExpr(const CXXConstructExpr *E,
582 AggValueSlot Dest) {
583 assert(!Dest.isIgnored() && "Must have a destination!");
584 const CXXConstructorDecl *CD = E->getConstructor();
585
586 // If we require zero initialization before (or instead of) calling the
587 // constructor, as can be the case with a non-user-provided default
588 // constructor, emit the zero initialization now, unless destination is
589 // already zeroed.
590 if (E->requiresZeroInitialization() && !Dest.isZeroed()) {
591 switch (E->getConstructionKind()) {
592 case CXXConstructExpr::CK_Delegating:
593 case CXXConstructExpr::CK_Complete:
594 EmitNullInitialization(Dest.getAddress(), E->getType());
595 break;
596 case CXXConstructExpr::CK_VirtualBase:
597 case CXXConstructExpr::CK_NonVirtualBase:
598 EmitNullBaseClassInitialization(*this, Dest.getAddress(),
599 CD->getParent());
600 break;
601 }
602 }
603
604 // If this is a call to a trivial default constructor, do nothing.
605 if (CD->isTrivial() && CD->isDefaultConstructor())
606 return;
607
608 // Elide the constructor if we're constructing from a temporary.
609 // The temporary check is required because Sema sets this on NRVO
610 // returns.
611 if (getLangOpts().ElideConstructors && E->isElidable()) {
612 assert(getContext().hasSameUnqualifiedType(E->getType(),
613 E->getArg(0)->getType()));
614 if (E->getArg(0)->isTemporaryObject(getContext(), CD->getParent())) {
615 EmitAggExpr(E->getArg(0), Dest);
616 return;
617 }
618 }
619
620 if (const ArrayType *arrayType
621 = getContext().getAsArrayType(E->getType())) {
622 EmitCXXAggrConstructorCall(CD, arrayType, Dest.getAddress(), E,
623 Dest.isSanitizerChecked());
624 } else {
625 CXXCtorType Type = Ctor_Complete;
626 bool ForVirtualBase = false;
627 bool Delegating = false;
628
629 switch (E->getConstructionKind()) {
630 case CXXConstructExpr::CK_Delegating:
631 // We should be emitting a constructor; GlobalDecl will assert this
632 Type = CurGD.getCtorType();
633 Delegating = true;
634 break;
635
636 case CXXConstructExpr::CK_Complete:
637 Type = Ctor_Complete;
638 break;
639
640 case CXXConstructExpr::CK_VirtualBase:
641 ForVirtualBase = true;
642 LLVM_FALLTHROUGH;
643
644 case CXXConstructExpr::CK_NonVirtualBase:
645 Type = Ctor_Base;
646 }
647
648 // Call the constructor.
649 EmitCXXConstructorCall(CD, Type, ForVirtualBase, Delegating, Dest, E);
650 }
651 }
652
EmitSynthesizedCXXCopyCtor(Address Dest,Address Src,const Expr * Exp)653 void CodeGenFunction::EmitSynthesizedCXXCopyCtor(Address Dest, Address Src,
654 const Expr *Exp) {
655 if (const ExprWithCleanups *E = dyn_cast<ExprWithCleanups>(Exp))
656 Exp = E->getSubExpr();
657 assert(isa<CXXConstructExpr>(Exp) &&
658 "EmitSynthesizedCXXCopyCtor - unknown copy ctor expr");
659 const CXXConstructExpr* E = cast<CXXConstructExpr>(Exp);
660 const CXXConstructorDecl *CD = E->getConstructor();
661 RunCleanupsScope Scope(*this);
662
663 // If we require zero initialization before (or instead of) calling the
664 // constructor, as can be the case with a non-user-provided default
665 // constructor, emit the zero initialization now.
666 // FIXME. Do I still need this for a copy ctor synthesis?
667 if (E->requiresZeroInitialization())
668 EmitNullInitialization(Dest, E->getType());
669
670 assert(!getContext().getAsConstantArrayType(E->getType())
671 && "EmitSynthesizedCXXCopyCtor - Copied-in Array");
672 EmitSynthesizedCXXCopyCtorCall(CD, Dest, Src, E);
673 }
674
CalculateCookiePadding(CodeGenFunction & CGF,const CXXNewExpr * E)675 static CharUnits CalculateCookiePadding(CodeGenFunction &CGF,
676 const CXXNewExpr *E) {
677 if (!E->isArray())
678 return CharUnits::Zero();
679
680 // No cookie is required if the operator new[] being used is the
681 // reserved placement operator new[].
682 if (E->getOperatorNew()->isReservedGlobalPlacementOperator())
683 return CharUnits::Zero();
684
685 return CGF.CGM.getCXXABI().GetArrayCookieSize(E);
686 }
687
EmitCXXNewAllocSize(CodeGenFunction & CGF,const CXXNewExpr * e,unsigned minElements,llvm::Value * & numElements,llvm::Value * & sizeWithoutCookie)688 static llvm::Value *EmitCXXNewAllocSize(CodeGenFunction &CGF,
689 const CXXNewExpr *e,
690 unsigned minElements,
691 llvm::Value *&numElements,
692 llvm::Value *&sizeWithoutCookie) {
693 QualType type = e->getAllocatedType();
694
695 if (!e->isArray()) {
696 CharUnits typeSize = CGF.getContext().getTypeSizeInChars(type);
697 sizeWithoutCookie
698 = llvm::ConstantInt::get(CGF.SizeTy, typeSize.getQuantity());
699 return sizeWithoutCookie;
700 }
701
702 // The width of size_t.
703 unsigned sizeWidth = CGF.SizeTy->getBitWidth();
704
705 // Figure out the cookie size.
706 llvm::APInt cookieSize(sizeWidth,
707 CalculateCookiePadding(CGF, e).getQuantity());
708
709 // Emit the array size expression.
710 // We multiply the size of all dimensions for NumElements.
711 // e.g for 'int[2][3]', ElemType is 'int' and NumElements is 6.
712 numElements =
713 ConstantEmitter(CGF).tryEmitAbstract(*e->getArraySize(), e->getType());
714 if (!numElements)
715 numElements = CGF.EmitScalarExpr(*e->getArraySize());
716 assert(isa<llvm::IntegerType>(numElements->getType()));
717
718 // The number of elements can be have an arbitrary integer type;
719 // essentially, we need to multiply it by a constant factor, add a
720 // cookie size, and verify that the result is representable as a
721 // size_t. That's just a gloss, though, and it's wrong in one
722 // important way: if the count is negative, it's an error even if
723 // the cookie size would bring the total size >= 0.
724 bool isSigned
725 = (*e->getArraySize())->getType()->isSignedIntegerOrEnumerationType();
726 llvm::IntegerType *numElementsType
727 = cast<llvm::IntegerType>(numElements->getType());
728 unsigned numElementsWidth = numElementsType->getBitWidth();
729
730 // Compute the constant factor.
731 llvm::APInt arraySizeMultiplier(sizeWidth, 1);
732 while (const ConstantArrayType *CAT
733 = CGF.getContext().getAsConstantArrayType(type)) {
734 type = CAT->getElementType();
735 arraySizeMultiplier *= CAT->getSize();
736 }
737
738 CharUnits typeSize = CGF.getContext().getTypeSizeInChars(type);
739 llvm::APInt typeSizeMultiplier(sizeWidth, typeSize.getQuantity());
740 typeSizeMultiplier *= arraySizeMultiplier;
741
742 // This will be a size_t.
743 llvm::Value *size;
744
745 // If someone is doing 'new int[42]' there is no need to do a dynamic check.
746 // Don't bloat the -O0 code.
747 if (llvm::ConstantInt *numElementsC =
748 dyn_cast<llvm::ConstantInt>(numElements)) {
749 const llvm::APInt &count = numElementsC->getValue();
750
751 bool hasAnyOverflow = false;
752
753 // If 'count' was a negative number, it's an overflow.
754 if (isSigned && count.isNegative())
755 hasAnyOverflow = true;
756
757 // We want to do all this arithmetic in size_t. If numElements is
758 // wider than that, check whether it's already too big, and if so,
759 // overflow.
760 else if (numElementsWidth > sizeWidth &&
761 numElementsWidth - sizeWidth > count.countLeadingZeros())
762 hasAnyOverflow = true;
763
764 // Okay, compute a count at the right width.
765 llvm::APInt adjustedCount = count.zextOrTrunc(sizeWidth);
766
767 // If there is a brace-initializer, we cannot allocate fewer elements than
768 // there are initializers. If we do, that's treated like an overflow.
769 if (adjustedCount.ult(minElements))
770 hasAnyOverflow = true;
771
772 // Scale numElements by that. This might overflow, but we don't
773 // care because it only overflows if allocationSize does, too, and
774 // if that overflows then we shouldn't use this.
775 numElements = llvm::ConstantInt::get(CGF.SizeTy,
776 adjustedCount * arraySizeMultiplier);
777
778 // Compute the size before cookie, and track whether it overflowed.
779 bool overflow;
780 llvm::APInt allocationSize
781 = adjustedCount.umul_ov(typeSizeMultiplier, overflow);
782 hasAnyOverflow |= overflow;
783
784 // Add in the cookie, and check whether it's overflowed.
785 if (cookieSize != 0) {
786 // Save the current size without a cookie. This shouldn't be
787 // used if there was overflow.
788 sizeWithoutCookie = llvm::ConstantInt::get(CGF.SizeTy, allocationSize);
789
790 allocationSize = allocationSize.uadd_ov(cookieSize, overflow);
791 hasAnyOverflow |= overflow;
792 }
793
794 // On overflow, produce a -1 so operator new will fail.
795 if (hasAnyOverflow) {
796 size = llvm::Constant::getAllOnesValue(CGF.SizeTy);
797 } else {
798 size = llvm::ConstantInt::get(CGF.SizeTy, allocationSize);
799 }
800
801 // Otherwise, we might need to use the overflow intrinsics.
802 } else {
803 // There are up to five conditions we need to test for:
804 // 1) if isSigned, we need to check whether numElements is negative;
805 // 2) if numElementsWidth > sizeWidth, we need to check whether
806 // numElements is larger than something representable in size_t;
807 // 3) if minElements > 0, we need to check whether numElements is smaller
808 // than that.
809 // 4) we need to compute
810 // sizeWithoutCookie := numElements * typeSizeMultiplier
811 // and check whether it overflows; and
812 // 5) if we need a cookie, we need to compute
813 // size := sizeWithoutCookie + cookieSize
814 // and check whether it overflows.
815
816 llvm::Value *hasOverflow = nullptr;
817
818 // If numElementsWidth > sizeWidth, then one way or another, we're
819 // going to have to do a comparison for (2), and this happens to
820 // take care of (1), too.
821 if (numElementsWidth > sizeWidth) {
822 llvm::APInt threshold(numElementsWidth, 1);
823 threshold <<= sizeWidth;
824
825 llvm::Value *thresholdV
826 = llvm::ConstantInt::get(numElementsType, threshold);
827
828 hasOverflow = CGF.Builder.CreateICmpUGE(numElements, thresholdV);
829 numElements = CGF.Builder.CreateTrunc(numElements, CGF.SizeTy);
830
831 // Otherwise, if we're signed, we want to sext up to size_t.
832 } else if (isSigned) {
833 if (numElementsWidth < sizeWidth)
834 numElements = CGF.Builder.CreateSExt(numElements, CGF.SizeTy);
835
836 // If there's a non-1 type size multiplier, then we can do the
837 // signedness check at the same time as we do the multiply
838 // because a negative number times anything will cause an
839 // unsigned overflow. Otherwise, we have to do it here. But at least
840 // in this case, we can subsume the >= minElements check.
841 if (typeSizeMultiplier == 1)
842 hasOverflow = CGF.Builder.CreateICmpSLT(numElements,
843 llvm::ConstantInt::get(CGF.SizeTy, minElements));
844
845 // Otherwise, zext up to size_t if necessary.
846 } else if (numElementsWidth < sizeWidth) {
847 numElements = CGF.Builder.CreateZExt(numElements, CGF.SizeTy);
848 }
849
850 assert(numElements->getType() == CGF.SizeTy);
851
852 if (minElements) {
853 // Don't allow allocation of fewer elements than we have initializers.
854 if (!hasOverflow) {
855 hasOverflow = CGF.Builder.CreateICmpULT(numElements,
856 llvm::ConstantInt::get(CGF.SizeTy, minElements));
857 } else if (numElementsWidth > sizeWidth) {
858 // The other existing overflow subsumes this check.
859 // We do an unsigned comparison, since any signed value < -1 is
860 // taken care of either above or below.
861 hasOverflow = CGF.Builder.CreateOr(hasOverflow,
862 CGF.Builder.CreateICmpULT(numElements,
863 llvm::ConstantInt::get(CGF.SizeTy, minElements)));
864 }
865 }
866
867 size = numElements;
868
869 // Multiply by the type size if necessary. This multiplier
870 // includes all the factors for nested arrays.
871 //
872 // This step also causes numElements to be scaled up by the
873 // nested-array factor if necessary. Overflow on this computation
874 // can be ignored because the result shouldn't be used if
875 // allocation fails.
876 if (typeSizeMultiplier != 1) {
877 llvm::Function *umul_with_overflow
878 = CGF.CGM.getIntrinsic(llvm::Intrinsic::umul_with_overflow, CGF.SizeTy);
879
880 llvm::Value *tsmV =
881 llvm::ConstantInt::get(CGF.SizeTy, typeSizeMultiplier);
882 llvm::Value *result =
883 CGF.Builder.CreateCall(umul_with_overflow, {size, tsmV});
884
885 llvm::Value *overflowed = CGF.Builder.CreateExtractValue(result, 1);
886 if (hasOverflow)
887 hasOverflow = CGF.Builder.CreateOr(hasOverflow, overflowed);
888 else
889 hasOverflow = overflowed;
890
891 size = CGF.Builder.CreateExtractValue(result, 0);
892
893 // Also scale up numElements by the array size multiplier.
894 if (arraySizeMultiplier != 1) {
895 // If the base element type size is 1, then we can re-use the
896 // multiply we just did.
897 if (typeSize.isOne()) {
898 assert(arraySizeMultiplier == typeSizeMultiplier);
899 numElements = size;
900
901 // Otherwise we need a separate multiply.
902 } else {
903 llvm::Value *asmV =
904 llvm::ConstantInt::get(CGF.SizeTy, arraySizeMultiplier);
905 numElements = CGF.Builder.CreateMul(numElements, asmV);
906 }
907 }
908 } else {
909 // numElements doesn't need to be scaled.
910 assert(arraySizeMultiplier == 1);
911 }
912
913 // Add in the cookie size if necessary.
914 if (cookieSize != 0) {
915 sizeWithoutCookie = size;
916
917 llvm::Function *uadd_with_overflow
918 = CGF.CGM.getIntrinsic(llvm::Intrinsic::uadd_with_overflow, CGF.SizeTy);
919
920 llvm::Value *cookieSizeV = llvm::ConstantInt::get(CGF.SizeTy, cookieSize);
921 llvm::Value *result =
922 CGF.Builder.CreateCall(uadd_with_overflow, {size, cookieSizeV});
923
924 llvm::Value *overflowed = CGF.Builder.CreateExtractValue(result, 1);
925 if (hasOverflow)
926 hasOverflow = CGF.Builder.CreateOr(hasOverflow, overflowed);
927 else
928 hasOverflow = overflowed;
929
930 size = CGF.Builder.CreateExtractValue(result, 0);
931 }
932
933 // If we had any possibility of dynamic overflow, make a select to
934 // overwrite 'size' with an all-ones value, which should cause
935 // operator new to throw.
936 if (hasOverflow)
937 size = CGF.Builder.CreateSelect(hasOverflow,
938 llvm::Constant::getAllOnesValue(CGF.SizeTy),
939 size);
940 }
941
942 if (cookieSize == 0)
943 sizeWithoutCookie = size;
944 else
945 assert(sizeWithoutCookie && "didn't set sizeWithoutCookie?");
946
947 return size;
948 }
949
StoreAnyExprIntoOneUnit(CodeGenFunction & CGF,const Expr * Init,QualType AllocType,Address NewPtr,AggValueSlot::Overlap_t MayOverlap)950 static void StoreAnyExprIntoOneUnit(CodeGenFunction &CGF, const Expr *Init,
951 QualType AllocType, Address NewPtr,
952 AggValueSlot::Overlap_t MayOverlap) {
953 // FIXME: Refactor with EmitExprAsInit.
954 switch (CGF.getEvaluationKind(AllocType)) {
955 case TEK_Scalar:
956 CGF.EmitScalarInit(Init, nullptr,
957 CGF.MakeAddrLValue(NewPtr, AllocType), false);
958 return;
959 case TEK_Complex:
960 CGF.EmitComplexExprIntoLValue(Init, CGF.MakeAddrLValue(NewPtr, AllocType),
961 /*isInit*/ true);
962 return;
963 case TEK_Aggregate: {
964 AggValueSlot Slot
965 = AggValueSlot::forAddr(NewPtr, AllocType.getQualifiers(),
966 AggValueSlot::IsDestructed,
967 AggValueSlot::DoesNotNeedGCBarriers,
968 AggValueSlot::IsNotAliased,
969 MayOverlap, AggValueSlot::IsNotZeroed,
970 AggValueSlot::IsSanitizerChecked);
971 CGF.EmitAggExpr(Init, Slot);
972 return;
973 }
974 }
975 llvm_unreachable("bad evaluation kind");
976 }
977
EmitNewArrayInitializer(const CXXNewExpr * E,QualType ElementType,llvm::Type * ElementTy,Address BeginPtr,llvm::Value * NumElements,llvm::Value * AllocSizeWithoutCookie)978 void CodeGenFunction::EmitNewArrayInitializer(
979 const CXXNewExpr *E, QualType ElementType, llvm::Type *ElementTy,
980 Address BeginPtr, llvm::Value *NumElements,
981 llvm::Value *AllocSizeWithoutCookie) {
982 // If we have a type with trivial initialization and no initializer,
983 // there's nothing to do.
984 if (!E->hasInitializer())
985 return;
986
987 Address CurPtr = BeginPtr;
988
989 unsigned InitListElements = 0;
990
991 const Expr *Init = E->getInitializer();
992 Address EndOfInit = Address::invalid();
993 QualType::DestructionKind DtorKind = ElementType.isDestructedType();
994 EHScopeStack::stable_iterator Cleanup;
995 llvm::Instruction *CleanupDominator = nullptr;
996
997 CharUnits ElementSize = getContext().getTypeSizeInChars(ElementType);
998 CharUnits ElementAlign =
999 BeginPtr.getAlignment().alignmentOfArrayElement(ElementSize);
1000
1001 // Attempt to perform zero-initialization using memset.
1002 auto TryMemsetInitialization = [&]() -> bool {
1003 // FIXME: If the type is a pointer-to-data-member under the Itanium ABI,
1004 // we can initialize with a memset to -1.
1005 if (!CGM.getTypes().isZeroInitializable(ElementType))
1006 return false;
1007
1008 // Optimization: since zero initialization will just set the memory
1009 // to all zeroes, generate a single memset to do it in one shot.
1010
1011 // Subtract out the size of any elements we've already initialized.
1012 auto *RemainingSize = AllocSizeWithoutCookie;
1013 if (InitListElements) {
1014 // We know this can't overflow; we check this when doing the allocation.
1015 auto *InitializedSize = llvm::ConstantInt::get(
1016 RemainingSize->getType(),
1017 getContext().getTypeSizeInChars(ElementType).getQuantity() *
1018 InitListElements);
1019 RemainingSize = Builder.CreateSub(RemainingSize, InitializedSize);
1020 }
1021
1022 // Create the memset.
1023 Builder.CreateMemSet(CurPtr, Builder.getInt8(0), RemainingSize, false);
1024 return true;
1025 };
1026
1027 // If the initializer is an initializer list, first do the explicit elements.
1028 if (const InitListExpr *ILE = dyn_cast<InitListExpr>(Init)) {
1029 // Initializing from a (braced) string literal is a special case; the init
1030 // list element does not initialize a (single) array element.
1031 if (ILE->isStringLiteralInit()) {
1032 // Initialize the initial portion of length equal to that of the string
1033 // literal. The allocation must be for at least this much; we emitted a
1034 // check for that earlier.
1035 AggValueSlot Slot =
1036 AggValueSlot::forAddr(CurPtr, ElementType.getQualifiers(),
1037 AggValueSlot::IsDestructed,
1038 AggValueSlot::DoesNotNeedGCBarriers,
1039 AggValueSlot::IsNotAliased,
1040 AggValueSlot::DoesNotOverlap,
1041 AggValueSlot::IsNotZeroed,
1042 AggValueSlot::IsSanitizerChecked);
1043 EmitAggExpr(ILE->getInit(0), Slot);
1044
1045 // Move past these elements.
1046 InitListElements =
1047 cast<ConstantArrayType>(ILE->getType()->getAsArrayTypeUnsafe())
1048 ->getSize().getZExtValue();
1049 CurPtr =
1050 Address(Builder.CreateInBoundsGEP(CurPtr.getPointer(),
1051 Builder.getSize(InitListElements),
1052 "string.init.end"),
1053 CurPtr.getAlignment().alignmentAtOffset(InitListElements *
1054 ElementSize));
1055
1056 // Zero out the rest, if any remain.
1057 llvm::ConstantInt *ConstNum = dyn_cast<llvm::ConstantInt>(NumElements);
1058 if (!ConstNum || !ConstNum->equalsInt(InitListElements)) {
1059 bool OK = TryMemsetInitialization();
1060 (void)OK;
1061 assert(OK && "couldn't memset character type?");
1062 }
1063 return;
1064 }
1065
1066 InitListElements = ILE->getNumInits();
1067
1068 // If this is a multi-dimensional array new, we will initialize multiple
1069 // elements with each init list element.
1070 QualType AllocType = E->getAllocatedType();
1071 if (const ConstantArrayType *CAT = dyn_cast_or_null<ConstantArrayType>(
1072 AllocType->getAsArrayTypeUnsafe())) {
1073 ElementTy = ConvertTypeForMem(AllocType);
1074 CurPtr = Builder.CreateElementBitCast(CurPtr, ElementTy);
1075 InitListElements *= getContext().getConstantArrayElementCount(CAT);
1076 }
1077
1078 // Enter a partial-destruction Cleanup if necessary.
1079 if (needsEHCleanup(DtorKind)) {
1080 // In principle we could tell the Cleanup where we are more
1081 // directly, but the control flow can get so varied here that it
1082 // would actually be quite complex. Therefore we go through an
1083 // alloca.
1084 EndOfInit = CreateTempAlloca(BeginPtr.getType(), getPointerAlign(),
1085 "array.init.end");
1086 CleanupDominator = Builder.CreateStore(BeginPtr.getPointer(), EndOfInit);
1087 pushIrregularPartialArrayCleanup(BeginPtr.getPointer(), EndOfInit,
1088 ElementType, ElementAlign,
1089 getDestroyer(DtorKind));
1090 Cleanup = EHStack.stable_begin();
1091 }
1092
1093 CharUnits StartAlign = CurPtr.getAlignment();
1094 for (unsigned i = 0, e = ILE->getNumInits(); i != e; ++i) {
1095 // Tell the cleanup that it needs to destroy up to this
1096 // element. TODO: some of these stores can be trivially
1097 // observed to be unnecessary.
1098 if (EndOfInit.isValid()) {
1099 auto FinishedPtr =
1100 Builder.CreateBitCast(CurPtr.getPointer(), BeginPtr.getType());
1101 Builder.CreateStore(FinishedPtr, EndOfInit);
1102 }
1103 // FIXME: If the last initializer is an incomplete initializer list for
1104 // an array, and we have an array filler, we can fold together the two
1105 // initialization loops.
1106 StoreAnyExprIntoOneUnit(*this, ILE->getInit(i),
1107 ILE->getInit(i)->getType(), CurPtr,
1108 AggValueSlot::DoesNotOverlap);
1109 CurPtr = Address(Builder.CreateInBoundsGEP(CurPtr.getPointer(),
1110 Builder.getSize(1),
1111 "array.exp.next"),
1112 StartAlign.alignmentAtOffset((i + 1) * ElementSize));
1113 }
1114
1115 // The remaining elements are filled with the array filler expression.
1116 Init = ILE->getArrayFiller();
1117
1118 // Extract the initializer for the individual array elements by pulling
1119 // out the array filler from all the nested initializer lists. This avoids
1120 // generating a nested loop for the initialization.
1121 while (Init && Init->getType()->isConstantArrayType()) {
1122 auto *SubILE = dyn_cast<InitListExpr>(Init);
1123 if (!SubILE)
1124 break;
1125 assert(SubILE->getNumInits() == 0 && "explicit inits in array filler?");
1126 Init = SubILE->getArrayFiller();
1127 }
1128
1129 // Switch back to initializing one base element at a time.
1130 CurPtr = Builder.CreateBitCast(CurPtr, BeginPtr.getType());
1131 }
1132
1133 // If all elements have already been initialized, skip any further
1134 // initialization.
1135 llvm::ConstantInt *ConstNum = dyn_cast<llvm::ConstantInt>(NumElements);
1136 if (ConstNum && ConstNum->getZExtValue() <= InitListElements) {
1137 // If there was a Cleanup, deactivate it.
1138 if (CleanupDominator)
1139 DeactivateCleanupBlock(Cleanup, CleanupDominator);
1140 return;
1141 }
1142
1143 assert(Init && "have trailing elements to initialize but no initializer");
1144
1145 // If this is a constructor call, try to optimize it out, and failing that
1146 // emit a single loop to initialize all remaining elements.
1147 if (const CXXConstructExpr *CCE = dyn_cast<CXXConstructExpr>(Init)) {
1148 CXXConstructorDecl *Ctor = CCE->getConstructor();
1149 if (Ctor->isTrivial()) {
1150 // If new expression did not specify value-initialization, then there
1151 // is no initialization.
1152 if (!CCE->requiresZeroInitialization() || Ctor->getParent()->isEmpty())
1153 return;
1154
1155 if (TryMemsetInitialization())
1156 return;
1157 }
1158
1159 // Store the new Cleanup position for irregular Cleanups.
1160 //
1161 // FIXME: Share this cleanup with the constructor call emission rather than
1162 // having it create a cleanup of its own.
1163 if (EndOfInit.isValid())
1164 Builder.CreateStore(CurPtr.getPointer(), EndOfInit);
1165
1166 // Emit a constructor call loop to initialize the remaining elements.
1167 if (InitListElements)
1168 NumElements = Builder.CreateSub(
1169 NumElements,
1170 llvm::ConstantInt::get(NumElements->getType(), InitListElements));
1171 EmitCXXAggrConstructorCall(Ctor, NumElements, CurPtr, CCE,
1172 /*NewPointerIsChecked*/true,
1173 CCE->requiresZeroInitialization());
1174 return;
1175 }
1176
1177 // If this is value-initialization, we can usually use memset.
1178 ImplicitValueInitExpr IVIE(ElementType);
1179 if (isa<ImplicitValueInitExpr>(Init)) {
1180 if (TryMemsetInitialization())
1181 return;
1182
1183 // Switch to an ImplicitValueInitExpr for the element type. This handles
1184 // only one case: multidimensional array new of pointers to members. In
1185 // all other cases, we already have an initializer for the array element.
1186 Init = &IVIE;
1187 }
1188
1189 // At this point we should have found an initializer for the individual
1190 // elements of the array.
1191 assert(getContext().hasSameUnqualifiedType(ElementType, Init->getType()) &&
1192 "got wrong type of element to initialize");
1193
1194 // If we have an empty initializer list, we can usually use memset.
1195 if (auto *ILE = dyn_cast<InitListExpr>(Init))
1196 if (ILE->getNumInits() == 0 && TryMemsetInitialization())
1197 return;
1198
1199 // If we have a struct whose every field is value-initialized, we can
1200 // usually use memset.
1201 if (auto *ILE = dyn_cast<InitListExpr>(Init)) {
1202 if (const RecordType *RType = ILE->getType()->getAs<RecordType>()) {
1203 if (RType->getDecl()->isStruct()) {
1204 unsigned NumElements = 0;
1205 if (auto *CXXRD = dyn_cast<CXXRecordDecl>(RType->getDecl()))
1206 NumElements = CXXRD->getNumBases();
1207 for (auto *Field : RType->getDecl()->fields())
1208 if (!Field->isUnnamedBitfield())
1209 ++NumElements;
1210 // FIXME: Recurse into nested InitListExprs.
1211 if (ILE->getNumInits() == NumElements)
1212 for (unsigned i = 0, e = ILE->getNumInits(); i != e; ++i)
1213 if (!isa<ImplicitValueInitExpr>(ILE->getInit(i)))
1214 --NumElements;
1215 if (ILE->getNumInits() == NumElements && TryMemsetInitialization())
1216 return;
1217 }
1218 }
1219 }
1220
1221 // Create the loop blocks.
1222 llvm::BasicBlock *EntryBB = Builder.GetInsertBlock();
1223 llvm::BasicBlock *LoopBB = createBasicBlock("new.loop");
1224 llvm::BasicBlock *ContBB = createBasicBlock("new.loop.end");
1225
1226 // Find the end of the array, hoisted out of the loop.
1227 llvm::Value *EndPtr =
1228 Builder.CreateInBoundsGEP(BeginPtr.getPointer(), NumElements, "array.end");
1229
1230 // If the number of elements isn't constant, we have to now check if there is
1231 // anything left to initialize.
1232 if (!ConstNum) {
1233 llvm::Value *IsEmpty =
1234 Builder.CreateICmpEQ(CurPtr.getPointer(), EndPtr, "array.isempty");
1235 Builder.CreateCondBr(IsEmpty, ContBB, LoopBB);
1236 }
1237
1238 // Enter the loop.
1239 EmitBlock(LoopBB);
1240
1241 // Set up the current-element phi.
1242 llvm::PHINode *CurPtrPhi =
1243 Builder.CreatePHI(CurPtr.getType(), 2, "array.cur");
1244 CurPtrPhi->addIncoming(CurPtr.getPointer(), EntryBB);
1245
1246 CurPtr = Address(CurPtrPhi, ElementAlign);
1247
1248 // Store the new Cleanup position for irregular Cleanups.
1249 if (EndOfInit.isValid())
1250 Builder.CreateStore(CurPtr.getPointer(), EndOfInit);
1251
1252 // Enter a partial-destruction Cleanup if necessary.
1253 if (!CleanupDominator && needsEHCleanup(DtorKind)) {
1254 pushRegularPartialArrayCleanup(BeginPtr.getPointer(), CurPtr.getPointer(),
1255 ElementType, ElementAlign,
1256 getDestroyer(DtorKind));
1257 Cleanup = EHStack.stable_begin();
1258 CleanupDominator = Builder.CreateUnreachable();
1259 }
1260
1261 // Emit the initializer into this element.
1262 StoreAnyExprIntoOneUnit(*this, Init, Init->getType(), CurPtr,
1263 AggValueSlot::DoesNotOverlap);
1264
1265 // Leave the Cleanup if we entered one.
1266 if (CleanupDominator) {
1267 DeactivateCleanupBlock(Cleanup, CleanupDominator);
1268 CleanupDominator->eraseFromParent();
1269 }
1270
1271 // Advance to the next element by adjusting the pointer type as necessary.
1272 llvm::Value *NextPtr =
1273 Builder.CreateConstInBoundsGEP1_32(ElementTy, CurPtr.getPointer(), 1,
1274 "array.next");
1275
1276 // Check whether we've gotten to the end of the array and, if so,
1277 // exit the loop.
1278 llvm::Value *IsEnd = Builder.CreateICmpEQ(NextPtr, EndPtr, "array.atend");
1279 Builder.CreateCondBr(IsEnd, ContBB, LoopBB);
1280 CurPtrPhi->addIncoming(NextPtr, Builder.GetInsertBlock());
1281
1282 EmitBlock(ContBB);
1283 }
1284
EmitNewInitializer(CodeGenFunction & CGF,const CXXNewExpr * E,QualType ElementType,llvm::Type * ElementTy,Address NewPtr,llvm::Value * NumElements,llvm::Value * AllocSizeWithoutCookie)1285 static void EmitNewInitializer(CodeGenFunction &CGF, const CXXNewExpr *E,
1286 QualType ElementType, llvm::Type *ElementTy,
1287 Address NewPtr, llvm::Value *NumElements,
1288 llvm::Value *AllocSizeWithoutCookie) {
1289 ApplyDebugLocation DL(CGF, E);
1290 if (E->isArray())
1291 CGF.EmitNewArrayInitializer(E, ElementType, ElementTy, NewPtr, NumElements,
1292 AllocSizeWithoutCookie);
1293 else if (const Expr *Init = E->getInitializer())
1294 StoreAnyExprIntoOneUnit(CGF, Init, E->getAllocatedType(), NewPtr,
1295 AggValueSlot::DoesNotOverlap);
1296 }
1297
1298 /// Emit a call to an operator new or operator delete function, as implicitly
1299 /// created by new-expressions and delete-expressions.
EmitNewDeleteCall(CodeGenFunction & CGF,const FunctionDecl * CalleeDecl,const FunctionProtoType * CalleeType,const CallArgList & Args)1300 static RValue EmitNewDeleteCall(CodeGenFunction &CGF,
1301 const FunctionDecl *CalleeDecl,
1302 const FunctionProtoType *CalleeType,
1303 const CallArgList &Args) {
1304 llvm::CallBase *CallOrInvoke;
1305 llvm::Constant *CalleePtr = CGF.CGM.GetAddrOfFunction(CalleeDecl);
1306 CGCallee Callee = CGCallee::forDirect(CalleePtr, GlobalDecl(CalleeDecl));
1307 RValue RV =
1308 CGF.EmitCall(CGF.CGM.getTypes().arrangeFreeFunctionCall(
1309 Args, CalleeType, /*ChainCall=*/false),
1310 Callee, ReturnValueSlot(), Args, &CallOrInvoke);
1311
1312 /// C++1y [expr.new]p10:
1313 /// [In a new-expression,] an implementation is allowed to omit a call
1314 /// to a replaceable global allocation function.
1315 ///
1316 /// We model such elidable calls with the 'builtin' attribute.
1317 llvm::Function *Fn = dyn_cast<llvm::Function>(CalleePtr);
1318 if (CalleeDecl->isReplaceableGlobalAllocationFunction() &&
1319 Fn && Fn->hasFnAttribute(llvm::Attribute::NoBuiltin)) {
1320 CallOrInvoke->addAttribute(llvm::AttributeList::FunctionIndex,
1321 llvm::Attribute::Builtin);
1322 }
1323
1324 return RV;
1325 }
1326
EmitBuiltinNewDeleteCall(const FunctionProtoType * Type,const CallExpr * TheCall,bool IsDelete)1327 RValue CodeGenFunction::EmitBuiltinNewDeleteCall(const FunctionProtoType *Type,
1328 const CallExpr *TheCall,
1329 bool IsDelete) {
1330 CallArgList Args;
1331 EmitCallArgs(Args, Type->getParamTypes(), TheCall->arguments());
1332 // Find the allocation or deallocation function that we're calling.
1333 ASTContext &Ctx = getContext();
1334 DeclarationName Name = Ctx.DeclarationNames
1335 .getCXXOperatorName(IsDelete ? OO_Delete : OO_New);
1336
1337 for (auto *Decl : Ctx.getTranslationUnitDecl()->lookup(Name))
1338 if (auto *FD = dyn_cast<FunctionDecl>(Decl))
1339 if (Ctx.hasSameType(FD->getType(), QualType(Type, 0)))
1340 return EmitNewDeleteCall(*this, FD, Type, Args);
1341 llvm_unreachable("predeclared global operator new/delete is missing");
1342 }
1343
1344 namespace {
1345 /// The parameters to pass to a usual operator delete.
1346 struct UsualDeleteParams {
1347 bool DestroyingDelete = false;
1348 bool Size = false;
1349 bool Alignment = false;
1350 };
1351 }
1352
getUsualDeleteParams(const FunctionDecl * FD)1353 static UsualDeleteParams getUsualDeleteParams(const FunctionDecl *FD) {
1354 UsualDeleteParams Params;
1355
1356 const FunctionProtoType *FPT = FD->getType()->castAs<FunctionProtoType>();
1357 auto AI = FPT->param_type_begin(), AE = FPT->param_type_end();
1358
1359 // The first argument is always a void*.
1360 ++AI;
1361
1362 // The next parameter may be a std::destroying_delete_t.
1363 if (FD->isDestroyingOperatorDelete()) {
1364 Params.DestroyingDelete = true;
1365 assert(AI != AE);
1366 ++AI;
1367 }
1368
1369 // Figure out what other parameters we should be implicitly passing.
1370 if (AI != AE && (*AI)->isIntegerType()) {
1371 Params.Size = true;
1372 ++AI;
1373 }
1374
1375 if (AI != AE && (*AI)->isAlignValT()) {
1376 Params.Alignment = true;
1377 ++AI;
1378 }
1379
1380 assert(AI == AE && "unexpected usual deallocation function parameter");
1381 return Params;
1382 }
1383
1384 namespace {
1385 /// A cleanup to call the given 'operator delete' function upon abnormal
1386 /// exit from a new expression. Templated on a traits type that deals with
1387 /// ensuring that the arguments dominate the cleanup if necessary.
1388 template<typename Traits>
1389 class CallDeleteDuringNew final : public EHScopeStack::Cleanup {
1390 /// Type used to hold llvm::Value*s.
1391 typedef typename Traits::ValueTy ValueTy;
1392 /// Type used to hold RValues.
1393 typedef typename Traits::RValueTy RValueTy;
1394 struct PlacementArg {
1395 RValueTy ArgValue;
1396 QualType ArgType;
1397 };
1398
1399 unsigned NumPlacementArgs : 31;
1400 unsigned PassAlignmentToPlacementDelete : 1;
1401 const FunctionDecl *OperatorDelete;
1402 ValueTy Ptr;
1403 ValueTy AllocSize;
1404 CharUnits AllocAlign;
1405
getPlacementArgs()1406 PlacementArg *getPlacementArgs() {
1407 return reinterpret_cast<PlacementArg *>(this + 1);
1408 }
1409
1410 public:
getExtraSize(size_t NumPlacementArgs)1411 static size_t getExtraSize(size_t NumPlacementArgs) {
1412 return NumPlacementArgs * sizeof(PlacementArg);
1413 }
1414
CallDeleteDuringNew(size_t NumPlacementArgs,const FunctionDecl * OperatorDelete,ValueTy Ptr,ValueTy AllocSize,bool PassAlignmentToPlacementDelete,CharUnits AllocAlign)1415 CallDeleteDuringNew(size_t NumPlacementArgs,
1416 const FunctionDecl *OperatorDelete, ValueTy Ptr,
1417 ValueTy AllocSize, bool PassAlignmentToPlacementDelete,
1418 CharUnits AllocAlign)
1419 : NumPlacementArgs(NumPlacementArgs),
1420 PassAlignmentToPlacementDelete(PassAlignmentToPlacementDelete),
1421 OperatorDelete(OperatorDelete), Ptr(Ptr), AllocSize(AllocSize),
1422 AllocAlign(AllocAlign) {}
1423
setPlacementArg(unsigned I,RValueTy Arg,QualType Type)1424 void setPlacementArg(unsigned I, RValueTy Arg, QualType Type) {
1425 assert(I < NumPlacementArgs && "index out of range");
1426 getPlacementArgs()[I] = {Arg, Type};
1427 }
1428
Emit(CodeGenFunction & CGF,Flags flags)1429 void Emit(CodeGenFunction &CGF, Flags flags) override {
1430 const auto *FPT = OperatorDelete->getType()->castAs<FunctionProtoType>();
1431 CallArgList DeleteArgs;
1432
1433 // The first argument is always a void* (or C* for a destroying operator
1434 // delete for class type C).
1435 DeleteArgs.add(Traits::get(CGF, Ptr), FPT->getParamType(0));
1436
1437 // Figure out what other parameters we should be implicitly passing.
1438 UsualDeleteParams Params;
1439 if (NumPlacementArgs) {
1440 // A placement deallocation function is implicitly passed an alignment
1441 // if the placement allocation function was, but is never passed a size.
1442 Params.Alignment = PassAlignmentToPlacementDelete;
1443 } else {
1444 // For a non-placement new-expression, 'operator delete' can take a
1445 // size and/or an alignment if it has the right parameters.
1446 Params = getUsualDeleteParams(OperatorDelete);
1447 }
1448
1449 assert(!Params.DestroyingDelete &&
1450 "should not call destroying delete in a new-expression");
1451
1452 // The second argument can be a std::size_t (for non-placement delete).
1453 if (Params.Size)
1454 DeleteArgs.add(Traits::get(CGF, AllocSize),
1455 CGF.getContext().getSizeType());
1456
1457 // The next (second or third) argument can be a std::align_val_t, which
1458 // is an enum whose underlying type is std::size_t.
1459 // FIXME: Use the right type as the parameter type. Note that in a call
1460 // to operator delete(size_t, ...), we may not have it available.
1461 if (Params.Alignment)
1462 DeleteArgs.add(RValue::get(llvm::ConstantInt::get(
1463 CGF.SizeTy, AllocAlign.getQuantity())),
1464 CGF.getContext().getSizeType());
1465
1466 // Pass the rest of the arguments, which must match exactly.
1467 for (unsigned I = 0; I != NumPlacementArgs; ++I) {
1468 auto Arg = getPlacementArgs()[I];
1469 DeleteArgs.add(Traits::get(CGF, Arg.ArgValue), Arg.ArgType);
1470 }
1471
1472 // Call 'operator delete'.
1473 EmitNewDeleteCall(CGF, OperatorDelete, FPT, DeleteArgs);
1474 }
1475 };
1476 }
1477
1478 /// Enter a cleanup to call 'operator delete' if the initializer in a
1479 /// new-expression throws.
EnterNewDeleteCleanup(CodeGenFunction & CGF,const CXXNewExpr * E,Address NewPtr,llvm::Value * AllocSize,CharUnits AllocAlign,const CallArgList & NewArgs)1480 static void EnterNewDeleteCleanup(CodeGenFunction &CGF,
1481 const CXXNewExpr *E,
1482 Address NewPtr,
1483 llvm::Value *AllocSize,
1484 CharUnits AllocAlign,
1485 const CallArgList &NewArgs) {
1486 unsigned NumNonPlacementArgs = E->passAlignment() ? 2 : 1;
1487
1488 // If we're not inside a conditional branch, then the cleanup will
1489 // dominate and we can do the easier (and more efficient) thing.
1490 if (!CGF.isInConditionalBranch()) {
1491 struct DirectCleanupTraits {
1492 typedef llvm::Value *ValueTy;
1493 typedef RValue RValueTy;
1494 static RValue get(CodeGenFunction &, ValueTy V) { return RValue::get(V); }
1495 static RValue get(CodeGenFunction &, RValueTy V) { return V; }
1496 };
1497
1498 typedef CallDeleteDuringNew<DirectCleanupTraits> DirectCleanup;
1499
1500 DirectCleanup *Cleanup = CGF.EHStack
1501 .pushCleanupWithExtra<DirectCleanup>(EHCleanup,
1502 E->getNumPlacementArgs(),
1503 E->getOperatorDelete(),
1504 NewPtr.getPointer(),
1505 AllocSize,
1506 E->passAlignment(),
1507 AllocAlign);
1508 for (unsigned I = 0, N = E->getNumPlacementArgs(); I != N; ++I) {
1509 auto &Arg = NewArgs[I + NumNonPlacementArgs];
1510 Cleanup->setPlacementArg(I, Arg.getRValue(CGF), Arg.Ty);
1511 }
1512
1513 return;
1514 }
1515
1516 // Otherwise, we need to save all this stuff.
1517 DominatingValue<RValue>::saved_type SavedNewPtr =
1518 DominatingValue<RValue>::save(CGF, RValue::get(NewPtr.getPointer()));
1519 DominatingValue<RValue>::saved_type SavedAllocSize =
1520 DominatingValue<RValue>::save(CGF, RValue::get(AllocSize));
1521
1522 struct ConditionalCleanupTraits {
1523 typedef DominatingValue<RValue>::saved_type ValueTy;
1524 typedef DominatingValue<RValue>::saved_type RValueTy;
1525 static RValue get(CodeGenFunction &CGF, ValueTy V) {
1526 return V.restore(CGF);
1527 }
1528 };
1529 typedef CallDeleteDuringNew<ConditionalCleanupTraits> ConditionalCleanup;
1530
1531 ConditionalCleanup *Cleanup = CGF.EHStack
1532 .pushCleanupWithExtra<ConditionalCleanup>(EHCleanup,
1533 E->getNumPlacementArgs(),
1534 E->getOperatorDelete(),
1535 SavedNewPtr,
1536 SavedAllocSize,
1537 E->passAlignment(),
1538 AllocAlign);
1539 for (unsigned I = 0, N = E->getNumPlacementArgs(); I != N; ++I) {
1540 auto &Arg = NewArgs[I + NumNonPlacementArgs];
1541 Cleanup->setPlacementArg(
1542 I, DominatingValue<RValue>::save(CGF, Arg.getRValue(CGF)), Arg.Ty);
1543 }
1544
1545 CGF.initFullExprCleanup();
1546 }
1547
EmitCXXNewExpr(const CXXNewExpr * E)1548 llvm::Value *CodeGenFunction::EmitCXXNewExpr(const CXXNewExpr *E) {
1549 // The element type being allocated.
1550 QualType allocType = getContext().getBaseElementType(E->getAllocatedType());
1551
1552 // 1. Build a call to the allocation function.
1553 FunctionDecl *allocator = E->getOperatorNew();
1554
1555 // If there is a brace-initializer, cannot allocate fewer elements than inits.
1556 unsigned minElements = 0;
1557 if (E->isArray() && E->hasInitializer()) {
1558 const InitListExpr *ILE = dyn_cast<InitListExpr>(E->getInitializer());
1559 if (ILE && ILE->isStringLiteralInit())
1560 minElements =
1561 cast<ConstantArrayType>(ILE->getType()->getAsArrayTypeUnsafe())
1562 ->getSize().getZExtValue();
1563 else if (ILE)
1564 minElements = ILE->getNumInits();
1565 }
1566
1567 llvm::Value *numElements = nullptr;
1568 llvm::Value *allocSizeWithoutCookie = nullptr;
1569 llvm::Value *allocSize =
1570 EmitCXXNewAllocSize(*this, E, minElements, numElements,
1571 allocSizeWithoutCookie);
1572 CharUnits allocAlign = getContext().getTypeAlignInChars(allocType);
1573
1574 // Emit the allocation call. If the allocator is a global placement
1575 // operator, just "inline" it directly.
1576 Address allocation = Address::invalid();
1577 CallArgList allocatorArgs;
1578 if (allocator->isReservedGlobalPlacementOperator()) {
1579 assert(E->getNumPlacementArgs() == 1);
1580 const Expr *arg = *E->placement_arguments().begin();
1581
1582 LValueBaseInfo BaseInfo;
1583 allocation = EmitPointerWithAlignment(arg, &BaseInfo);
1584
1585 // The pointer expression will, in many cases, be an opaque void*.
1586 // In these cases, discard the computed alignment and use the
1587 // formal alignment of the allocated type.
1588 if (BaseInfo.getAlignmentSource() != AlignmentSource::Decl)
1589 allocation = Address(allocation.getPointer(), allocAlign);
1590
1591 // Set up allocatorArgs for the call to operator delete if it's not
1592 // the reserved global operator.
1593 if (E->getOperatorDelete() &&
1594 !E->getOperatorDelete()->isReservedGlobalPlacementOperator()) {
1595 allocatorArgs.add(RValue::get(allocSize), getContext().getSizeType());
1596 allocatorArgs.add(RValue::get(allocation.getPointer()), arg->getType());
1597 }
1598
1599 } else {
1600 const FunctionProtoType *allocatorType =
1601 allocator->getType()->castAs<FunctionProtoType>();
1602 unsigned ParamsToSkip = 0;
1603
1604 // The allocation size is the first argument.
1605 QualType sizeType = getContext().getSizeType();
1606 allocatorArgs.add(RValue::get(allocSize), sizeType);
1607 ++ParamsToSkip;
1608
1609 if (allocSize != allocSizeWithoutCookie) {
1610 CharUnits cookieAlign = getSizeAlign(); // FIXME: Ask the ABI.
1611 allocAlign = std::max(allocAlign, cookieAlign);
1612 }
1613
1614 // The allocation alignment may be passed as the second argument.
1615 if (E->passAlignment()) {
1616 QualType AlignValT = sizeType;
1617 if (allocatorType->getNumParams() > 1) {
1618 AlignValT = allocatorType->getParamType(1);
1619 assert(getContext().hasSameUnqualifiedType(
1620 AlignValT->castAs<EnumType>()->getDecl()->getIntegerType(),
1621 sizeType) &&
1622 "wrong type for alignment parameter");
1623 ++ParamsToSkip;
1624 } else {
1625 // Corner case, passing alignment to 'operator new(size_t, ...)'.
1626 assert(allocator->isVariadic() && "can't pass alignment to allocator");
1627 }
1628 allocatorArgs.add(
1629 RValue::get(llvm::ConstantInt::get(SizeTy, allocAlign.getQuantity())),
1630 AlignValT);
1631 }
1632
1633 // FIXME: Why do we not pass a CalleeDecl here?
1634 EmitCallArgs(allocatorArgs, allocatorType, E->placement_arguments(),
1635 /*AC*/AbstractCallee(), /*ParamsToSkip*/ParamsToSkip);
1636
1637 RValue RV =
1638 EmitNewDeleteCall(*this, allocator, allocatorType, allocatorArgs);
1639
1640 // If this was a call to a global replaceable allocation function that does
1641 // not take an alignment argument, the allocator is known to produce
1642 // storage that's suitably aligned for any object that fits, up to a known
1643 // threshold. Otherwise assume it's suitably aligned for the allocated type.
1644 CharUnits allocationAlign = allocAlign;
1645 if (!E->passAlignment() &&
1646 allocator->isReplaceableGlobalAllocationFunction()) {
1647 unsigned AllocatorAlign = llvm::PowerOf2Floor(std::min<uint64_t>(
1648 Target.getNewAlign(), getContext().getTypeSize(allocType)));
1649 allocationAlign = std::max(
1650 allocationAlign, getContext().toCharUnitsFromBits(AllocatorAlign));
1651 }
1652
1653 allocation = Address(RV.getScalarVal(), allocationAlign);
1654 }
1655
1656 // Emit a null check on the allocation result if the allocation
1657 // function is allowed to return null (because it has a non-throwing
1658 // exception spec or is the reserved placement new) and we have an
1659 // interesting initializer will be running sanitizers on the initialization.
1660 bool nullCheck = E->shouldNullCheckAllocation() &&
1661 (!allocType.isPODType(getContext()) || E->hasInitializer() ||
1662 sanitizePerformTypeCheck());
1663
1664 llvm::BasicBlock *nullCheckBB = nullptr;
1665 llvm::BasicBlock *contBB = nullptr;
1666
1667 // The null-check means that the initializer is conditionally
1668 // evaluated.
1669 ConditionalEvaluation conditional(*this);
1670
1671 if (nullCheck) {
1672 conditional.begin(*this);
1673
1674 nullCheckBB = Builder.GetInsertBlock();
1675 llvm::BasicBlock *notNullBB = createBasicBlock("new.notnull");
1676 contBB = createBasicBlock("new.cont");
1677
1678 llvm::Value *isNull =
1679 Builder.CreateIsNull(allocation.getPointer(), "new.isnull");
1680 Builder.CreateCondBr(isNull, contBB, notNullBB);
1681 EmitBlock(notNullBB);
1682 }
1683
1684 // If there's an operator delete, enter a cleanup to call it if an
1685 // exception is thrown.
1686 EHScopeStack::stable_iterator operatorDeleteCleanup;
1687 llvm::Instruction *cleanupDominator = nullptr;
1688 if (E->getOperatorDelete() &&
1689 !E->getOperatorDelete()->isReservedGlobalPlacementOperator()) {
1690 EnterNewDeleteCleanup(*this, E, allocation, allocSize, allocAlign,
1691 allocatorArgs);
1692 operatorDeleteCleanup = EHStack.stable_begin();
1693 cleanupDominator = Builder.CreateUnreachable();
1694 }
1695
1696 assert((allocSize == allocSizeWithoutCookie) ==
1697 CalculateCookiePadding(*this, E).isZero());
1698 if (allocSize != allocSizeWithoutCookie) {
1699 assert(E->isArray());
1700 allocation = CGM.getCXXABI().InitializeArrayCookie(*this, allocation,
1701 numElements,
1702 E, allocType);
1703 }
1704
1705 llvm::Type *elementTy = ConvertTypeForMem(allocType);
1706 Address result = Builder.CreateElementBitCast(allocation, elementTy);
1707
1708 // Passing pointer through launder.invariant.group to avoid propagation of
1709 // vptrs information which may be included in previous type.
1710 // To not break LTO with different optimizations levels, we do it regardless
1711 // of optimization level.
1712 if (CGM.getCodeGenOpts().StrictVTablePointers &&
1713 allocator->isReservedGlobalPlacementOperator())
1714 result = Address(Builder.CreateLaunderInvariantGroup(result.getPointer()),
1715 result.getAlignment());
1716
1717 // Emit sanitizer checks for pointer value now, so that in the case of an
1718 // array it was checked only once and not at each constructor call. We may
1719 // have already checked that the pointer is non-null.
1720 // FIXME: If we have an array cookie and a potentially-throwing allocator,
1721 // we'll null check the wrong pointer here.
1722 SanitizerSet SkippedChecks;
1723 SkippedChecks.set(SanitizerKind::Null, nullCheck);
1724 EmitTypeCheck(CodeGenFunction::TCK_ConstructorCall,
1725 E->getAllocatedTypeSourceInfo()->getTypeLoc().getBeginLoc(),
1726 result.getPointer(), allocType, result.getAlignment(),
1727 SkippedChecks, numElements);
1728
1729 EmitNewInitializer(*this, E, allocType, elementTy, result, numElements,
1730 allocSizeWithoutCookie);
1731 if (E->isArray()) {
1732 // NewPtr is a pointer to the base element type. If we're
1733 // allocating an array of arrays, we'll need to cast back to the
1734 // array pointer type.
1735 llvm::Type *resultType = ConvertTypeForMem(E->getType());
1736 if (result.getType() != resultType)
1737 result = Builder.CreateBitCast(result, resultType);
1738 }
1739
1740 // Deactivate the 'operator delete' cleanup if we finished
1741 // initialization.
1742 if (operatorDeleteCleanup.isValid()) {
1743 DeactivateCleanupBlock(operatorDeleteCleanup, cleanupDominator);
1744 cleanupDominator->eraseFromParent();
1745 }
1746
1747 llvm::Value *resultPtr = result.getPointer();
1748 if (nullCheck) {
1749 conditional.end(*this);
1750
1751 llvm::BasicBlock *notNullBB = Builder.GetInsertBlock();
1752 EmitBlock(contBB);
1753
1754 llvm::PHINode *PHI = Builder.CreatePHI(resultPtr->getType(), 2);
1755 PHI->addIncoming(resultPtr, notNullBB);
1756 PHI->addIncoming(llvm::Constant::getNullValue(resultPtr->getType()),
1757 nullCheckBB);
1758
1759 resultPtr = PHI;
1760 }
1761
1762 return resultPtr;
1763 }
1764
EmitDeleteCall(const FunctionDecl * DeleteFD,llvm::Value * Ptr,QualType DeleteTy,llvm::Value * NumElements,CharUnits CookieSize)1765 void CodeGenFunction::EmitDeleteCall(const FunctionDecl *DeleteFD,
1766 llvm::Value *Ptr, QualType DeleteTy,
1767 llvm::Value *NumElements,
1768 CharUnits CookieSize) {
1769 assert((!NumElements && CookieSize.isZero()) ||
1770 DeleteFD->getOverloadedOperator() == OO_Array_Delete);
1771
1772 const auto *DeleteFTy = DeleteFD->getType()->castAs<FunctionProtoType>();
1773 CallArgList DeleteArgs;
1774
1775 auto Params = getUsualDeleteParams(DeleteFD);
1776 auto ParamTypeIt = DeleteFTy->param_type_begin();
1777
1778 // Pass the pointer itself.
1779 QualType ArgTy = *ParamTypeIt++;
1780 llvm::Value *DeletePtr = Builder.CreateBitCast(Ptr, ConvertType(ArgTy));
1781 DeleteArgs.add(RValue::get(DeletePtr), ArgTy);
1782
1783 // Pass the std::destroying_delete tag if present.
1784 if (Params.DestroyingDelete) {
1785 QualType DDTag = *ParamTypeIt++;
1786 // Just pass an 'undef'. We expect the tag type to be an empty struct.
1787 auto *V = llvm::UndefValue::get(getTypes().ConvertType(DDTag));
1788 DeleteArgs.add(RValue::get(V), DDTag);
1789 }
1790
1791 // Pass the size if the delete function has a size_t parameter.
1792 if (Params.Size) {
1793 QualType SizeType = *ParamTypeIt++;
1794 CharUnits DeleteTypeSize = getContext().getTypeSizeInChars(DeleteTy);
1795 llvm::Value *Size = llvm::ConstantInt::get(ConvertType(SizeType),
1796 DeleteTypeSize.getQuantity());
1797
1798 // For array new, multiply by the number of elements.
1799 if (NumElements)
1800 Size = Builder.CreateMul(Size, NumElements);
1801
1802 // If there is a cookie, add the cookie size.
1803 if (!CookieSize.isZero())
1804 Size = Builder.CreateAdd(
1805 Size, llvm::ConstantInt::get(SizeTy, CookieSize.getQuantity()));
1806
1807 DeleteArgs.add(RValue::get(Size), SizeType);
1808 }
1809
1810 // Pass the alignment if the delete function has an align_val_t parameter.
1811 if (Params.Alignment) {
1812 QualType AlignValType = *ParamTypeIt++;
1813 CharUnits DeleteTypeAlign = getContext().toCharUnitsFromBits(
1814 getContext().getTypeAlignIfKnown(DeleteTy));
1815 llvm::Value *Align = llvm::ConstantInt::get(ConvertType(AlignValType),
1816 DeleteTypeAlign.getQuantity());
1817 DeleteArgs.add(RValue::get(Align), AlignValType);
1818 }
1819
1820 assert(ParamTypeIt == DeleteFTy->param_type_end() &&
1821 "unknown parameter to usual delete function");
1822
1823 // Emit the call to delete.
1824 EmitNewDeleteCall(*this, DeleteFD, DeleteFTy, DeleteArgs);
1825 }
1826
1827 namespace {
1828 /// Calls the given 'operator delete' on a single object.
1829 struct CallObjectDelete final : EHScopeStack::Cleanup {
1830 llvm::Value *Ptr;
1831 const FunctionDecl *OperatorDelete;
1832 QualType ElementType;
1833
CallObjectDelete__anon66f77eea0511::CallObjectDelete1834 CallObjectDelete(llvm::Value *Ptr,
1835 const FunctionDecl *OperatorDelete,
1836 QualType ElementType)
1837 : Ptr(Ptr), OperatorDelete(OperatorDelete), ElementType(ElementType) {}
1838
Emit__anon66f77eea0511::CallObjectDelete1839 void Emit(CodeGenFunction &CGF, Flags flags) override {
1840 CGF.EmitDeleteCall(OperatorDelete, Ptr, ElementType);
1841 }
1842 };
1843 }
1844
1845 void
pushCallObjectDeleteCleanup(const FunctionDecl * OperatorDelete,llvm::Value * CompletePtr,QualType ElementType)1846 CodeGenFunction::pushCallObjectDeleteCleanup(const FunctionDecl *OperatorDelete,
1847 llvm::Value *CompletePtr,
1848 QualType ElementType) {
1849 EHStack.pushCleanup<CallObjectDelete>(NormalAndEHCleanup, CompletePtr,
1850 OperatorDelete, ElementType);
1851 }
1852
1853 /// Emit the code for deleting a single object with a destroying operator
1854 /// delete. If the element type has a non-virtual destructor, Ptr has already
1855 /// been converted to the type of the parameter of 'operator delete'. Otherwise
1856 /// Ptr points to an object of the static type.
EmitDestroyingObjectDelete(CodeGenFunction & CGF,const CXXDeleteExpr * DE,Address Ptr,QualType ElementType)1857 static void EmitDestroyingObjectDelete(CodeGenFunction &CGF,
1858 const CXXDeleteExpr *DE, Address Ptr,
1859 QualType ElementType) {
1860 auto *Dtor = ElementType->getAsCXXRecordDecl()->getDestructor();
1861 if (Dtor && Dtor->isVirtual())
1862 CGF.CGM.getCXXABI().emitVirtualObjectDelete(CGF, DE, Ptr, ElementType,
1863 Dtor);
1864 else
1865 CGF.EmitDeleteCall(DE->getOperatorDelete(), Ptr.getPointer(), ElementType);
1866 }
1867
1868 /// Emit the code for deleting a single object.
EmitObjectDelete(CodeGenFunction & CGF,const CXXDeleteExpr * DE,Address Ptr,QualType ElementType)1869 static void EmitObjectDelete(CodeGenFunction &CGF,
1870 const CXXDeleteExpr *DE,
1871 Address Ptr,
1872 QualType ElementType) {
1873 // C++11 [expr.delete]p3:
1874 // If the static type of the object to be deleted is different from its
1875 // dynamic type, the static type shall be a base class of the dynamic type
1876 // of the object to be deleted and the static type shall have a virtual
1877 // destructor or the behavior is undefined.
1878 CGF.EmitTypeCheck(CodeGenFunction::TCK_MemberCall,
1879 DE->getExprLoc(), Ptr.getPointer(),
1880 ElementType);
1881
1882 const FunctionDecl *OperatorDelete = DE->getOperatorDelete();
1883 assert(!OperatorDelete->isDestroyingOperatorDelete());
1884
1885 // Find the destructor for the type, if applicable. If the
1886 // destructor is virtual, we'll just emit the vcall and return.
1887 const CXXDestructorDecl *Dtor = nullptr;
1888 if (const RecordType *RT = ElementType->getAs<RecordType>()) {
1889 CXXRecordDecl *RD = cast<CXXRecordDecl>(RT->getDecl());
1890 if (RD->hasDefinition() && !RD->hasTrivialDestructor()) {
1891 Dtor = RD->getDestructor();
1892
1893 if (Dtor->isVirtual()) {
1894 bool UseVirtualCall = true;
1895 const Expr *Base = DE->getArgument();
1896 if (auto *DevirtualizedDtor =
1897 dyn_cast_or_null<const CXXDestructorDecl>(
1898 Dtor->getDevirtualizedMethod(
1899 Base, CGF.CGM.getLangOpts().AppleKext))) {
1900 UseVirtualCall = false;
1901 const CXXRecordDecl *DevirtualizedClass =
1902 DevirtualizedDtor->getParent();
1903 if (declaresSameEntity(getCXXRecord(Base), DevirtualizedClass)) {
1904 // Devirtualized to the class of the base type (the type of the
1905 // whole expression).
1906 Dtor = DevirtualizedDtor;
1907 } else {
1908 // Devirtualized to some other type. Would need to cast the this
1909 // pointer to that type but we don't have support for that yet, so
1910 // do a virtual call. FIXME: handle the case where it is
1911 // devirtualized to the derived type (the type of the inner
1912 // expression) as in EmitCXXMemberOrOperatorMemberCallExpr.
1913 UseVirtualCall = true;
1914 }
1915 }
1916 if (UseVirtualCall) {
1917 CGF.CGM.getCXXABI().emitVirtualObjectDelete(CGF, DE, Ptr, ElementType,
1918 Dtor);
1919 return;
1920 }
1921 }
1922 }
1923 }
1924
1925 // Make sure that we call delete even if the dtor throws.
1926 // This doesn't have to a conditional cleanup because we're going
1927 // to pop it off in a second.
1928 CGF.EHStack.pushCleanup<CallObjectDelete>(NormalAndEHCleanup,
1929 Ptr.getPointer(),
1930 OperatorDelete, ElementType);
1931
1932 if (Dtor)
1933 CGF.EmitCXXDestructorCall(Dtor, Dtor_Complete,
1934 /*ForVirtualBase=*/false,
1935 /*Delegating=*/false,
1936 Ptr, ElementType);
1937 else if (auto Lifetime = ElementType.getObjCLifetime()) {
1938 switch (Lifetime) {
1939 case Qualifiers::OCL_None:
1940 case Qualifiers::OCL_ExplicitNone:
1941 case Qualifiers::OCL_Autoreleasing:
1942 break;
1943
1944 case Qualifiers::OCL_Strong:
1945 CGF.EmitARCDestroyStrong(Ptr, ARCPreciseLifetime);
1946 break;
1947
1948 case Qualifiers::OCL_Weak:
1949 CGF.EmitARCDestroyWeak(Ptr);
1950 break;
1951 }
1952 }
1953
1954 CGF.PopCleanupBlock();
1955 }
1956
1957 namespace {
1958 /// Calls the given 'operator delete' on an array of objects.
1959 struct CallArrayDelete final : EHScopeStack::Cleanup {
1960 llvm::Value *Ptr;
1961 const FunctionDecl *OperatorDelete;
1962 llvm::Value *NumElements;
1963 QualType ElementType;
1964 CharUnits CookieSize;
1965
CallArrayDelete__anon66f77eea0611::CallArrayDelete1966 CallArrayDelete(llvm::Value *Ptr,
1967 const FunctionDecl *OperatorDelete,
1968 llvm::Value *NumElements,
1969 QualType ElementType,
1970 CharUnits CookieSize)
1971 : Ptr(Ptr), OperatorDelete(OperatorDelete), NumElements(NumElements),
1972 ElementType(ElementType), CookieSize(CookieSize) {}
1973
Emit__anon66f77eea0611::CallArrayDelete1974 void Emit(CodeGenFunction &CGF, Flags flags) override {
1975 CGF.EmitDeleteCall(OperatorDelete, Ptr, ElementType, NumElements,
1976 CookieSize);
1977 }
1978 };
1979 }
1980
1981 /// Emit the code for deleting an array of objects.
EmitArrayDelete(CodeGenFunction & CGF,const CXXDeleteExpr * E,Address deletedPtr,QualType elementType)1982 static void EmitArrayDelete(CodeGenFunction &CGF,
1983 const CXXDeleteExpr *E,
1984 Address deletedPtr,
1985 QualType elementType) {
1986 llvm::Value *numElements = nullptr;
1987 llvm::Value *allocatedPtr = nullptr;
1988 CharUnits cookieSize;
1989 CGF.CGM.getCXXABI().ReadArrayCookie(CGF, deletedPtr, E, elementType,
1990 numElements, allocatedPtr, cookieSize);
1991
1992 assert(allocatedPtr && "ReadArrayCookie didn't set allocated pointer");
1993
1994 // Make sure that we call delete even if one of the dtors throws.
1995 const FunctionDecl *operatorDelete = E->getOperatorDelete();
1996 CGF.EHStack.pushCleanup<CallArrayDelete>(NormalAndEHCleanup,
1997 allocatedPtr, operatorDelete,
1998 numElements, elementType,
1999 cookieSize);
2000
2001 // Destroy the elements.
2002 if (QualType::DestructionKind dtorKind = elementType.isDestructedType()) {
2003 assert(numElements && "no element count for a type with a destructor!");
2004
2005 CharUnits elementSize = CGF.getContext().getTypeSizeInChars(elementType);
2006 CharUnits elementAlign =
2007 deletedPtr.getAlignment().alignmentOfArrayElement(elementSize);
2008
2009 llvm::Value *arrayBegin = deletedPtr.getPointer();
2010 llvm::Value *arrayEnd =
2011 CGF.Builder.CreateInBoundsGEP(arrayBegin, numElements, "delete.end");
2012
2013 // Note that it is legal to allocate a zero-length array, and we
2014 // can never fold the check away because the length should always
2015 // come from a cookie.
2016 CGF.emitArrayDestroy(arrayBegin, arrayEnd, elementType, elementAlign,
2017 CGF.getDestroyer(dtorKind),
2018 /*checkZeroLength*/ true,
2019 CGF.needsEHCleanup(dtorKind));
2020 }
2021
2022 // Pop the cleanup block.
2023 CGF.PopCleanupBlock();
2024 }
2025
EmitCXXDeleteExpr(const CXXDeleteExpr * E)2026 void CodeGenFunction::EmitCXXDeleteExpr(const CXXDeleteExpr *E) {
2027 const Expr *Arg = E->getArgument();
2028 Address Ptr = EmitPointerWithAlignment(Arg);
2029
2030 // Null check the pointer.
2031 llvm::BasicBlock *DeleteNotNull = createBasicBlock("delete.notnull");
2032 llvm::BasicBlock *DeleteEnd = createBasicBlock("delete.end");
2033
2034 llvm::Value *IsNull = Builder.CreateIsNull(Ptr.getPointer(), "isnull");
2035
2036 Builder.CreateCondBr(IsNull, DeleteEnd, DeleteNotNull);
2037 EmitBlock(DeleteNotNull);
2038
2039 QualType DeleteTy = E->getDestroyedType();
2040
2041 // A destroying operator delete overrides the entire operation of the
2042 // delete expression.
2043 if (E->getOperatorDelete()->isDestroyingOperatorDelete()) {
2044 EmitDestroyingObjectDelete(*this, E, Ptr, DeleteTy);
2045 EmitBlock(DeleteEnd);
2046 return;
2047 }
2048
2049 // We might be deleting a pointer to array. If so, GEP down to the
2050 // first non-array element.
2051 // (this assumes that A(*)[3][7] is converted to [3 x [7 x %A]]*)
2052 if (DeleteTy->isConstantArrayType()) {
2053 llvm::Value *Zero = Builder.getInt32(0);
2054 SmallVector<llvm::Value*,8> GEP;
2055
2056 GEP.push_back(Zero); // point at the outermost array
2057
2058 // For each layer of array type we're pointing at:
2059 while (const ConstantArrayType *Arr
2060 = getContext().getAsConstantArrayType(DeleteTy)) {
2061 // 1. Unpeel the array type.
2062 DeleteTy = Arr->getElementType();
2063
2064 // 2. GEP to the first element of the array.
2065 GEP.push_back(Zero);
2066 }
2067
2068 Ptr = Address(Builder.CreateInBoundsGEP(Ptr.getPointer(), GEP, "del.first"),
2069 Ptr.getAlignment());
2070 }
2071
2072 assert(ConvertTypeForMem(DeleteTy) == Ptr.getElementType());
2073
2074 if (E->isArrayForm()) {
2075 EmitArrayDelete(*this, E, Ptr, DeleteTy);
2076 } else {
2077 EmitObjectDelete(*this, E, Ptr, DeleteTy);
2078 }
2079
2080 EmitBlock(DeleteEnd);
2081 }
2082
isGLValueFromPointerDeref(const Expr * E)2083 static bool isGLValueFromPointerDeref(const Expr *E) {
2084 E = E->IgnoreParens();
2085
2086 if (const auto *CE = dyn_cast<CastExpr>(E)) {
2087 if (!CE->getSubExpr()->isGLValue())
2088 return false;
2089 return isGLValueFromPointerDeref(CE->getSubExpr());
2090 }
2091
2092 if (const auto *OVE = dyn_cast<OpaqueValueExpr>(E))
2093 return isGLValueFromPointerDeref(OVE->getSourceExpr());
2094
2095 if (const auto *BO = dyn_cast<BinaryOperator>(E))
2096 if (BO->getOpcode() == BO_Comma)
2097 return isGLValueFromPointerDeref(BO->getRHS());
2098
2099 if (const auto *ACO = dyn_cast<AbstractConditionalOperator>(E))
2100 return isGLValueFromPointerDeref(ACO->getTrueExpr()) ||
2101 isGLValueFromPointerDeref(ACO->getFalseExpr());
2102
2103 // C++11 [expr.sub]p1:
2104 // The expression E1[E2] is identical (by definition) to *((E1)+(E2))
2105 if (isa<ArraySubscriptExpr>(E))
2106 return true;
2107
2108 if (const auto *UO = dyn_cast<UnaryOperator>(E))
2109 if (UO->getOpcode() == UO_Deref)
2110 return true;
2111
2112 return false;
2113 }
2114
EmitTypeidFromVTable(CodeGenFunction & CGF,const Expr * E,llvm::Type * StdTypeInfoPtrTy)2115 static llvm::Value *EmitTypeidFromVTable(CodeGenFunction &CGF, const Expr *E,
2116 llvm::Type *StdTypeInfoPtrTy) {
2117 // Get the vtable pointer.
2118 Address ThisPtr = CGF.EmitLValue(E).getAddress(CGF);
2119
2120 QualType SrcRecordTy = E->getType();
2121
2122 // C++ [class.cdtor]p4:
2123 // If the operand of typeid refers to the object under construction or
2124 // destruction and the static type of the operand is neither the constructor
2125 // or destructor’s class nor one of its bases, the behavior is undefined.
2126 CGF.EmitTypeCheck(CodeGenFunction::TCK_DynamicOperation, E->getExprLoc(),
2127 ThisPtr.getPointer(), SrcRecordTy);
2128
2129 // C++ [expr.typeid]p2:
2130 // If the glvalue expression is obtained by applying the unary * operator to
2131 // a pointer and the pointer is a null pointer value, the typeid expression
2132 // throws the std::bad_typeid exception.
2133 //
2134 // However, this paragraph's intent is not clear. We choose a very generous
2135 // interpretation which implores us to consider comma operators, conditional
2136 // operators, parentheses and other such constructs.
2137 if (CGF.CGM.getCXXABI().shouldTypeidBeNullChecked(
2138 isGLValueFromPointerDeref(E), SrcRecordTy)) {
2139 llvm::BasicBlock *BadTypeidBlock =
2140 CGF.createBasicBlock("typeid.bad_typeid");
2141 llvm::BasicBlock *EndBlock = CGF.createBasicBlock("typeid.end");
2142
2143 llvm::Value *IsNull = CGF.Builder.CreateIsNull(ThisPtr.getPointer());
2144 CGF.Builder.CreateCondBr(IsNull, BadTypeidBlock, EndBlock);
2145
2146 CGF.EmitBlock(BadTypeidBlock);
2147 CGF.CGM.getCXXABI().EmitBadTypeidCall(CGF);
2148 CGF.EmitBlock(EndBlock);
2149 }
2150
2151 return CGF.CGM.getCXXABI().EmitTypeid(CGF, SrcRecordTy, ThisPtr,
2152 StdTypeInfoPtrTy);
2153 }
2154
EmitCXXTypeidExpr(const CXXTypeidExpr * E)2155 llvm::Value *CodeGenFunction::EmitCXXTypeidExpr(const CXXTypeidExpr *E) {
2156 llvm::Type *StdTypeInfoPtrTy =
2157 ConvertType(E->getType())->getPointerTo();
2158
2159 if (E->isTypeOperand()) {
2160 llvm::Constant *TypeInfo =
2161 CGM.GetAddrOfRTTIDescriptor(E->getTypeOperand(getContext()));
2162 return Builder.CreateBitCast(TypeInfo, StdTypeInfoPtrTy);
2163 }
2164
2165 // C++ [expr.typeid]p2:
2166 // When typeid is applied to a glvalue expression whose type is a
2167 // polymorphic class type, the result refers to a std::type_info object
2168 // representing the type of the most derived object (that is, the dynamic
2169 // type) to which the glvalue refers.
2170 if (E->isPotentiallyEvaluated())
2171 return EmitTypeidFromVTable(*this, E->getExprOperand(),
2172 StdTypeInfoPtrTy);
2173
2174 QualType OperandTy = E->getExprOperand()->getType();
2175 return Builder.CreateBitCast(CGM.GetAddrOfRTTIDescriptor(OperandTy),
2176 StdTypeInfoPtrTy);
2177 }
2178
EmitDynamicCastToNull(CodeGenFunction & CGF,QualType DestTy)2179 static llvm::Value *EmitDynamicCastToNull(CodeGenFunction &CGF,
2180 QualType DestTy) {
2181 llvm::Type *DestLTy = CGF.ConvertType(DestTy);
2182 if (DestTy->isPointerType())
2183 return llvm::Constant::getNullValue(DestLTy);
2184
2185 /// C++ [expr.dynamic.cast]p9:
2186 /// A failed cast to reference type throws std::bad_cast
2187 if (!CGF.CGM.getCXXABI().EmitBadCastCall(CGF))
2188 return nullptr;
2189
2190 CGF.EmitBlock(CGF.createBasicBlock("dynamic_cast.end"));
2191 return llvm::UndefValue::get(DestLTy);
2192 }
2193
EmitDynamicCast(Address ThisAddr,const CXXDynamicCastExpr * DCE)2194 llvm::Value *CodeGenFunction::EmitDynamicCast(Address ThisAddr,
2195 const CXXDynamicCastExpr *DCE) {
2196 CGM.EmitExplicitCastExprType(DCE, this);
2197 QualType DestTy = DCE->getTypeAsWritten();
2198
2199 QualType SrcTy = DCE->getSubExpr()->getType();
2200
2201 // C++ [expr.dynamic.cast]p7:
2202 // If T is "pointer to cv void," then the result is a pointer to the most
2203 // derived object pointed to by v.
2204 const PointerType *DestPTy = DestTy->getAs<PointerType>();
2205
2206 bool isDynamicCastToVoid;
2207 QualType SrcRecordTy;
2208 QualType DestRecordTy;
2209 if (DestPTy) {
2210 isDynamicCastToVoid = DestPTy->getPointeeType()->isVoidType();
2211 SrcRecordTy = SrcTy->castAs<PointerType>()->getPointeeType();
2212 DestRecordTy = DestPTy->getPointeeType();
2213 } else {
2214 isDynamicCastToVoid = false;
2215 SrcRecordTy = SrcTy;
2216 DestRecordTy = DestTy->castAs<ReferenceType>()->getPointeeType();
2217 }
2218
2219 // C++ [class.cdtor]p5:
2220 // If the operand of the dynamic_cast refers to the object under
2221 // construction or destruction and the static type of the operand is not a
2222 // pointer to or object of the constructor or destructor’s own class or one
2223 // of its bases, the dynamic_cast results in undefined behavior.
2224 EmitTypeCheck(TCK_DynamicOperation, DCE->getExprLoc(), ThisAddr.getPointer(),
2225 SrcRecordTy);
2226
2227 if (DCE->isAlwaysNull())
2228 if (llvm::Value *T = EmitDynamicCastToNull(*this, DestTy))
2229 return T;
2230
2231 assert(SrcRecordTy->isRecordType() && "source type must be a record type!");
2232
2233 // C++ [expr.dynamic.cast]p4:
2234 // If the value of v is a null pointer value in the pointer case, the result
2235 // is the null pointer value of type T.
2236 bool ShouldNullCheckSrcValue =
2237 CGM.getCXXABI().shouldDynamicCastCallBeNullChecked(SrcTy->isPointerType(),
2238 SrcRecordTy);
2239
2240 llvm::BasicBlock *CastNull = nullptr;
2241 llvm::BasicBlock *CastNotNull = nullptr;
2242 llvm::BasicBlock *CastEnd = createBasicBlock("dynamic_cast.end");
2243
2244 if (ShouldNullCheckSrcValue) {
2245 CastNull = createBasicBlock("dynamic_cast.null");
2246 CastNotNull = createBasicBlock("dynamic_cast.notnull");
2247
2248 llvm::Value *IsNull = Builder.CreateIsNull(ThisAddr.getPointer());
2249 Builder.CreateCondBr(IsNull, CastNull, CastNotNull);
2250 EmitBlock(CastNotNull);
2251 }
2252
2253 llvm::Value *Value;
2254 if (isDynamicCastToVoid) {
2255 Value = CGM.getCXXABI().EmitDynamicCastToVoid(*this, ThisAddr, SrcRecordTy,
2256 DestTy);
2257 } else {
2258 assert(DestRecordTy->isRecordType() &&
2259 "destination type must be a record type!");
2260 Value = CGM.getCXXABI().EmitDynamicCastCall(*this, ThisAddr, SrcRecordTy,
2261 DestTy, DestRecordTy, CastEnd);
2262 CastNotNull = Builder.GetInsertBlock();
2263 }
2264
2265 if (ShouldNullCheckSrcValue) {
2266 EmitBranch(CastEnd);
2267
2268 EmitBlock(CastNull);
2269 EmitBranch(CastEnd);
2270 }
2271
2272 EmitBlock(CastEnd);
2273
2274 if (ShouldNullCheckSrcValue) {
2275 llvm::PHINode *PHI = Builder.CreatePHI(Value->getType(), 2);
2276 PHI->addIncoming(Value, CastNotNull);
2277 PHI->addIncoming(llvm::Constant::getNullValue(Value->getType()), CastNull);
2278
2279 Value = PHI;
2280 }
2281
2282 return Value;
2283 }
2284