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, nullptr,
116 CE ? CE->getExprLoc() : SourceLocation{});
117 }
118
EmitCXXPseudoDestructorExpr(const CXXPseudoDestructorExpr * E)119 RValue CodeGenFunction::EmitCXXPseudoDestructorExpr(
120 const CXXPseudoDestructorExpr *E) {
121 QualType DestroyedType = E->getDestroyedType();
122 if (DestroyedType.hasStrongOrWeakObjCLifetime()) {
123 // Automatic Reference Counting:
124 // If the pseudo-expression names a retainable object with weak or
125 // strong lifetime, the object shall be released.
126 Expr *BaseExpr = E->getBase();
127 Address BaseValue = Address::invalid();
128 Qualifiers BaseQuals;
129
130 // If this is s.x, emit s as an lvalue. If it is s->x, emit s as a scalar.
131 if (E->isArrow()) {
132 BaseValue = EmitPointerWithAlignment(BaseExpr);
133 const auto *PTy = BaseExpr->getType()->castAs<PointerType>();
134 BaseQuals = PTy->getPointeeType().getQualifiers();
135 } else {
136 LValue BaseLV = EmitLValue(BaseExpr);
137 BaseValue = BaseLV.getAddress(*this);
138 QualType BaseTy = BaseExpr->getType();
139 BaseQuals = BaseTy.getQualifiers();
140 }
141
142 switch (DestroyedType.getObjCLifetime()) {
143 case Qualifiers::OCL_None:
144 case Qualifiers::OCL_ExplicitNone:
145 case Qualifiers::OCL_Autoreleasing:
146 break;
147
148 case Qualifiers::OCL_Strong:
149 EmitARCRelease(Builder.CreateLoad(BaseValue,
150 DestroyedType.isVolatileQualified()),
151 ARCPreciseLifetime);
152 break;
153
154 case Qualifiers::OCL_Weak:
155 EmitARCDestroyWeak(BaseValue);
156 break;
157 }
158 } else {
159 // C++ [expr.pseudo]p1:
160 // The result shall only be used as the operand for the function call
161 // operator (), and the result of such a call has type void. The only
162 // effect is the evaluation of the postfix-expression before the dot or
163 // arrow.
164 EmitIgnoredExpr(E->getBase());
165 }
166
167 return RValue::get(nullptr);
168 }
169
getCXXRecord(const Expr * E)170 static CXXRecordDecl *getCXXRecord(const Expr *E) {
171 QualType T = E->getType();
172 if (const PointerType *PTy = T->getAs<PointerType>())
173 T = PTy->getPointeeType();
174 const RecordType *Ty = T->castAs<RecordType>();
175 return cast<CXXRecordDecl>(Ty->getDecl());
176 }
177
178 // Note: This function also emit constructor calls to support a MSVC
179 // extensions allowing explicit constructor function call.
EmitCXXMemberCallExpr(const CXXMemberCallExpr * CE,ReturnValueSlot ReturnValue)180 RValue CodeGenFunction::EmitCXXMemberCallExpr(const CXXMemberCallExpr *CE,
181 ReturnValueSlot ReturnValue) {
182 const Expr *callee = CE->getCallee()->IgnoreParens();
183
184 if (isa<BinaryOperator>(callee))
185 return EmitCXXMemberPointerCallExpr(CE, ReturnValue);
186
187 const MemberExpr *ME = cast<MemberExpr>(callee);
188 const CXXMethodDecl *MD = cast<CXXMethodDecl>(ME->getMemberDecl());
189
190 if (MD->isStatic()) {
191 // The method is static, emit it as we would a regular call.
192 CGCallee callee =
193 CGCallee::forDirect(CGM.GetAddrOfFunction(MD), GlobalDecl(MD));
194 return EmitCall(getContext().getPointerType(MD->getType()), callee, CE,
195 ReturnValue);
196 }
197
198 bool HasQualifier = ME->hasQualifier();
199 NestedNameSpecifier *Qualifier = HasQualifier ? ME->getQualifier() : nullptr;
200 bool IsArrow = ME->isArrow();
201 const Expr *Base = ME->getBase();
202
203 return EmitCXXMemberOrOperatorMemberCallExpr(
204 CE, MD, ReturnValue, HasQualifier, Qualifier, IsArrow, Base);
205 }
206
EmitCXXMemberOrOperatorMemberCallExpr(const CallExpr * CE,const CXXMethodDecl * MD,ReturnValueSlot ReturnValue,bool HasQualifier,NestedNameSpecifier * Qualifier,bool IsArrow,const Expr * Base)207 RValue CodeGenFunction::EmitCXXMemberOrOperatorMemberCallExpr(
208 const CallExpr *CE, const CXXMethodDecl *MD, ReturnValueSlot ReturnValue,
209 bool HasQualifier, NestedNameSpecifier *Qualifier, bool IsArrow,
210 const Expr *Base) {
211 assert(isa<CXXMemberCallExpr>(CE) || isa<CXXOperatorCallExpr>(CE));
212
213 // Compute the object pointer.
214 bool CanUseVirtualCall = MD->isVirtual() && !HasQualifier;
215
216 const CXXMethodDecl *DevirtualizedMethod = nullptr;
217 if (CanUseVirtualCall &&
218 MD->getDevirtualizedMethod(Base, getLangOpts().AppleKext)) {
219 const CXXRecordDecl *BestDynamicDecl = Base->getBestDynamicClassType();
220 DevirtualizedMethod = MD->getCorrespondingMethodInClass(BestDynamicDecl);
221 assert(DevirtualizedMethod);
222 const CXXRecordDecl *DevirtualizedClass = DevirtualizedMethod->getParent();
223 const Expr *Inner = Base->IgnoreParenBaseCasts();
224 if (DevirtualizedMethod->getReturnType().getCanonicalType() !=
225 MD->getReturnType().getCanonicalType())
226 // If the return types are not the same, this might be a case where more
227 // code needs to run to compensate for it. For example, the derived
228 // method might return a type that inherits form from the return
229 // type of MD and has a prefix.
230 // For now we just avoid devirtualizing these covariant cases.
231 DevirtualizedMethod = nullptr;
232 else if (getCXXRecord(Inner) == DevirtualizedClass)
233 // If the class of the Inner expression is where the dynamic method
234 // is defined, build the this pointer from it.
235 Base = Inner;
236 else if (getCXXRecord(Base) != DevirtualizedClass) {
237 // If the method is defined in a class that is not the best dynamic
238 // one or the one of the full expression, we would have to build
239 // a derived-to-base cast to compute the correct this pointer, but
240 // we don't have support for that yet, so do a virtual call.
241 DevirtualizedMethod = nullptr;
242 }
243 }
244
245 bool TrivialForCodegen =
246 MD->isTrivial() || (MD->isDefaulted() && MD->getParent()->isUnion());
247 bool TrivialAssignment =
248 TrivialForCodegen &&
249 (MD->isCopyAssignmentOperator() || MD->isMoveAssignmentOperator()) &&
250 !MD->getParent()->mayInsertExtraPadding();
251
252 // C++17 demands that we evaluate the RHS of a (possibly-compound) assignment
253 // operator before the LHS.
254 CallArgList RtlArgStorage;
255 CallArgList *RtlArgs = nullptr;
256 LValue TrivialAssignmentRHS;
257 if (auto *OCE = dyn_cast<CXXOperatorCallExpr>(CE)) {
258 if (OCE->isAssignmentOp()) {
259 if (TrivialAssignment) {
260 TrivialAssignmentRHS = EmitLValue(CE->getArg(1));
261 } else {
262 RtlArgs = &RtlArgStorage;
263 EmitCallArgs(*RtlArgs, MD->getType()->castAs<FunctionProtoType>(),
264 drop_begin(CE->arguments(), 1), CE->getDirectCallee(),
265 /*ParamsToSkip*/0, EvaluationOrder::ForceRightToLeft);
266 }
267 }
268 }
269
270 LValue This;
271 if (IsArrow) {
272 LValueBaseInfo BaseInfo;
273 TBAAAccessInfo TBAAInfo;
274 Address ThisValue = EmitPointerWithAlignment(Base, &BaseInfo, &TBAAInfo);
275 This = MakeAddrLValue(ThisValue, Base->getType(), BaseInfo, TBAAInfo);
276 } else {
277 This = EmitLValue(Base);
278 }
279
280 if (const CXXConstructorDecl *Ctor = dyn_cast<CXXConstructorDecl>(MD)) {
281 // This is the MSVC p->Ctor::Ctor(...) extension. We assume that's
282 // constructing a new complete object of type Ctor.
283 assert(!RtlArgs);
284 assert(ReturnValue.isNull() && "Constructor shouldn't have return value");
285 CallArgList Args;
286 commonEmitCXXMemberOrOperatorCall(
287 *this, Ctor, This.getPointer(*this), /*ImplicitParam=*/nullptr,
288 /*ImplicitParamTy=*/QualType(), CE, Args, nullptr);
289
290 EmitCXXConstructorCall(Ctor, Ctor_Complete, /*ForVirtualBase=*/false,
291 /*Delegating=*/false, This.getAddress(*this), Args,
292 AggValueSlot::DoesNotOverlap, CE->getExprLoc(),
293 /*NewPointerIsChecked=*/false);
294 return RValue::get(nullptr);
295 }
296
297 if (TrivialForCodegen) {
298 if (isa<CXXDestructorDecl>(MD))
299 return RValue::get(nullptr);
300
301 if (TrivialAssignment) {
302 // We don't like to generate the trivial copy/move assignment operator
303 // when it isn't necessary; just produce the proper effect here.
304 // It's important that we use the result of EmitLValue here rather than
305 // emitting call arguments, in order to preserve TBAA information from
306 // the RHS.
307 LValue RHS = isa<CXXOperatorCallExpr>(CE)
308 ? TrivialAssignmentRHS
309 : EmitLValue(*CE->arg_begin());
310 EmitAggregateAssign(This, RHS, CE->getType());
311 return RValue::get(This.getPointer(*this));
312 }
313
314 assert(MD->getParent()->mayInsertExtraPadding() &&
315 "unknown trivial member function");
316 }
317
318 // Compute the function type we're calling.
319 const CXXMethodDecl *CalleeDecl =
320 DevirtualizedMethod ? DevirtualizedMethod : MD;
321 const CGFunctionInfo *FInfo = nullptr;
322 if (const auto *Dtor = dyn_cast<CXXDestructorDecl>(CalleeDecl))
323 FInfo = &CGM.getTypes().arrangeCXXStructorDeclaration(
324 GlobalDecl(Dtor, Dtor_Complete));
325 else
326 FInfo = &CGM.getTypes().arrangeCXXMethodDeclaration(CalleeDecl);
327
328 llvm::FunctionType *Ty = CGM.getTypes().GetFunctionType(*FInfo);
329
330 // C++11 [class.mfct.non-static]p2:
331 // If a non-static member function of a class X is called for an object that
332 // is not of type X, or of a type derived from X, the behavior is undefined.
333 SourceLocation CallLoc;
334 ASTContext &C = getContext();
335 if (CE)
336 CallLoc = CE->getExprLoc();
337
338 SanitizerSet SkippedChecks;
339 if (const auto *CMCE = dyn_cast<CXXMemberCallExpr>(CE)) {
340 auto *IOA = CMCE->getImplicitObjectArgument();
341 bool IsImplicitObjectCXXThis = IsWrappedCXXThis(IOA);
342 if (IsImplicitObjectCXXThis)
343 SkippedChecks.set(SanitizerKind::Alignment, true);
344 if (IsImplicitObjectCXXThis || isa<DeclRefExpr>(IOA))
345 SkippedChecks.set(SanitizerKind::Null, true);
346 }
347 EmitTypeCheck(CodeGenFunction::TCK_MemberCall, CallLoc,
348 This.getPointer(*this),
349 C.getRecordType(CalleeDecl->getParent()),
350 /*Alignment=*/CharUnits::Zero(), SkippedChecks);
351
352 // C++ [class.virtual]p12:
353 // Explicit qualification with the scope operator (5.1) suppresses the
354 // virtual call mechanism.
355 //
356 // We also don't emit a virtual call if the base expression has a record type
357 // because then we know what the type is.
358 bool UseVirtualCall = CanUseVirtualCall && !DevirtualizedMethod;
359
360 if (const CXXDestructorDecl *Dtor = dyn_cast<CXXDestructorDecl>(CalleeDecl)) {
361 assert(CE->arg_begin() == CE->arg_end() &&
362 "Destructor shouldn't have explicit parameters");
363 assert(ReturnValue.isNull() && "Destructor shouldn't have return value");
364 if (UseVirtualCall) {
365 CGM.getCXXABI().EmitVirtualDestructorCall(*this, Dtor, Dtor_Complete,
366 This.getAddress(*this),
367 cast<CXXMemberCallExpr>(CE));
368 } else {
369 GlobalDecl GD(Dtor, Dtor_Complete);
370 CGCallee Callee;
371 if (getLangOpts().AppleKext && Dtor->isVirtual() && HasQualifier)
372 Callee = BuildAppleKextVirtualCall(Dtor, Qualifier, Ty);
373 else if (!DevirtualizedMethod)
374 Callee =
375 CGCallee::forDirect(CGM.getAddrOfCXXStructor(GD, FInfo, Ty), GD);
376 else {
377 Callee = CGCallee::forDirect(CGM.GetAddrOfFunction(GD, Ty), GD);
378 }
379
380 QualType ThisTy =
381 IsArrow ? Base->getType()->getPointeeType() : Base->getType();
382 EmitCXXDestructorCall(GD, Callee, This.getPointer(*this), ThisTy,
383 /*ImplicitParam=*/nullptr,
384 /*ImplicitParamTy=*/QualType(), CE);
385 }
386 return RValue::get(nullptr);
387 }
388
389 // FIXME: Uses of 'MD' past this point need to be audited. We may need to use
390 // 'CalleeDecl' instead.
391
392 CGCallee Callee;
393 if (UseVirtualCall) {
394 Callee = CGCallee::forVirtual(CE, MD, This.getAddress(*this), Ty);
395 } else {
396 if (SanOpts.has(SanitizerKind::CFINVCall) &&
397 MD->getParent()->isDynamicClass()) {
398 llvm::Value *VTable;
399 const CXXRecordDecl *RD;
400 std::tie(VTable, RD) = CGM.getCXXABI().LoadVTablePtr(
401 *this, This.getAddress(*this), CalleeDecl->getParent());
402 EmitVTablePtrCheckForCall(RD, VTable, CFITCK_NVCall, CE->getBeginLoc());
403 }
404
405 if (getLangOpts().AppleKext && MD->isVirtual() && HasQualifier)
406 Callee = BuildAppleKextVirtualCall(MD, Qualifier, Ty);
407 else if (!DevirtualizedMethod)
408 Callee =
409 CGCallee::forDirect(CGM.GetAddrOfFunction(MD, Ty), GlobalDecl(MD));
410 else {
411 Callee =
412 CGCallee::forDirect(CGM.GetAddrOfFunction(DevirtualizedMethod, Ty),
413 GlobalDecl(DevirtualizedMethod));
414 }
415 }
416
417 if (MD->isVirtual()) {
418 Address NewThisAddr =
419 CGM.getCXXABI().adjustThisArgumentForVirtualFunctionCall(
420 *this, CalleeDecl, This.getAddress(*this), UseVirtualCall);
421 This.setAddress(NewThisAddr);
422 }
423
424 return EmitCXXMemberOrOperatorCall(
425 CalleeDecl, Callee, ReturnValue, This.getPointer(*this),
426 /*ImplicitParam=*/nullptr, QualType(), CE, RtlArgs);
427 }
428
429 RValue
EmitCXXMemberPointerCallExpr(const CXXMemberCallExpr * E,ReturnValueSlot ReturnValue)430 CodeGenFunction::EmitCXXMemberPointerCallExpr(const CXXMemberCallExpr *E,
431 ReturnValueSlot ReturnValue) {
432 const BinaryOperator *BO =
433 cast<BinaryOperator>(E->getCallee()->IgnoreParens());
434 const Expr *BaseExpr = BO->getLHS();
435 const Expr *MemFnExpr = BO->getRHS();
436
437 const auto *MPT = MemFnExpr->getType()->castAs<MemberPointerType>();
438 const auto *FPT = MPT->getPointeeType()->castAs<FunctionProtoType>();
439 const auto *RD =
440 cast<CXXRecordDecl>(MPT->getClass()->castAs<RecordType>()->getDecl());
441
442 // Emit the 'this' pointer.
443 Address This = Address::invalid();
444 if (BO->getOpcode() == BO_PtrMemI)
445 This = EmitPointerWithAlignment(BaseExpr);
446 else
447 This = EmitLValue(BaseExpr).getAddress(*this);
448
449 EmitTypeCheck(TCK_MemberCall, E->getExprLoc(), This.getPointer(),
450 QualType(MPT->getClass(), 0));
451
452 // Get the member function pointer.
453 llvm::Value *MemFnPtr = EmitScalarExpr(MemFnExpr);
454
455 // Ask the ABI to load the callee. Note that This is modified.
456 llvm::Value *ThisPtrForCall = nullptr;
457 CGCallee Callee =
458 CGM.getCXXABI().EmitLoadOfMemberFunctionPointer(*this, BO, This,
459 ThisPtrForCall, MemFnPtr, MPT);
460
461 CallArgList Args;
462
463 QualType ThisType =
464 getContext().getPointerType(getContext().getTagDeclType(RD));
465
466 // Push the this ptr.
467 Args.add(RValue::get(ThisPtrForCall), ThisType);
468
469 RequiredArgs required = RequiredArgs::forPrototypePlus(FPT, 1);
470
471 // And the rest of the call args
472 EmitCallArgs(Args, FPT, E->arguments());
473 return EmitCall(CGM.getTypes().arrangeCXXMethodCall(Args, FPT, required,
474 /*PrefixSize=*/0),
475 Callee, ReturnValue, Args, nullptr, E->getExprLoc());
476 }
477
478 RValue
EmitCXXOperatorMemberCallExpr(const CXXOperatorCallExpr * E,const CXXMethodDecl * MD,ReturnValueSlot ReturnValue)479 CodeGenFunction::EmitCXXOperatorMemberCallExpr(const CXXOperatorCallExpr *E,
480 const CXXMethodDecl *MD,
481 ReturnValueSlot ReturnValue) {
482 assert(MD->isInstance() &&
483 "Trying to emit a member call expr on a static method!");
484 return EmitCXXMemberOrOperatorMemberCallExpr(
485 E, MD, ReturnValue, /*HasQualifier=*/false, /*Qualifier=*/nullptr,
486 /*IsArrow=*/false, E->getArg(0));
487 }
488
EmitCUDAKernelCallExpr(const CUDAKernelCallExpr * E,ReturnValueSlot ReturnValue)489 RValue CodeGenFunction::EmitCUDAKernelCallExpr(const CUDAKernelCallExpr *E,
490 ReturnValueSlot ReturnValue) {
491 return CGM.getCUDARuntime().EmitCUDAKernelCallExpr(*this, E, ReturnValue);
492 }
493
EmitNullBaseClassInitialization(CodeGenFunction & CGF,Address DestPtr,const CXXRecordDecl * Base)494 static void EmitNullBaseClassInitialization(CodeGenFunction &CGF,
495 Address DestPtr,
496 const CXXRecordDecl *Base) {
497 if (Base->isEmpty())
498 return;
499
500 DestPtr = CGF.Builder.CreateElementBitCast(DestPtr, CGF.Int8Ty);
501
502 const ASTRecordLayout &Layout = CGF.getContext().getASTRecordLayout(Base);
503 CharUnits NVSize = Layout.getNonVirtualSize();
504
505 // We cannot simply zero-initialize the entire base sub-object if vbptrs are
506 // present, they are initialized by the most derived class before calling the
507 // constructor.
508 SmallVector<std::pair<CharUnits, CharUnits>, 1> Stores;
509 Stores.emplace_back(CharUnits::Zero(), NVSize);
510
511 // Each store is split by the existence of a vbptr.
512 CharUnits VBPtrWidth = CGF.getPointerSize();
513 std::vector<CharUnits> VBPtrOffsets =
514 CGF.CGM.getCXXABI().getVBPtrOffsets(Base);
515 for (CharUnits VBPtrOffset : VBPtrOffsets) {
516 // Stop before we hit any virtual base pointers located in virtual bases.
517 if (VBPtrOffset >= NVSize)
518 break;
519 std::pair<CharUnits, CharUnits> LastStore = Stores.pop_back_val();
520 CharUnits LastStoreOffset = LastStore.first;
521 CharUnits LastStoreSize = LastStore.second;
522
523 CharUnits SplitBeforeOffset = LastStoreOffset;
524 CharUnits SplitBeforeSize = VBPtrOffset - SplitBeforeOffset;
525 assert(!SplitBeforeSize.isNegative() && "negative store size!");
526 if (!SplitBeforeSize.isZero())
527 Stores.emplace_back(SplitBeforeOffset, SplitBeforeSize);
528
529 CharUnits SplitAfterOffset = VBPtrOffset + VBPtrWidth;
530 CharUnits SplitAfterSize = LastStoreSize - SplitAfterOffset;
531 assert(!SplitAfterSize.isNegative() && "negative store size!");
532 if (!SplitAfterSize.isZero())
533 Stores.emplace_back(SplitAfterOffset, SplitAfterSize);
534 }
535
536 // If the type contains a pointer to data member we can't memset it to zero.
537 // Instead, create a null constant and copy it to the destination.
538 // TODO: there are other patterns besides zero that we can usefully memset,
539 // like -1, which happens to be the pattern used by member-pointers.
540 // TODO: isZeroInitializable can be over-conservative in the case where a
541 // virtual base contains a member pointer.
542 llvm::Constant *NullConstantForBase = CGF.CGM.EmitNullConstantForBase(Base);
543 if (!NullConstantForBase->isNullValue()) {
544 llvm::GlobalVariable *NullVariable = new llvm::GlobalVariable(
545 CGF.CGM.getModule(), NullConstantForBase->getType(),
546 /*isConstant=*/true, llvm::GlobalVariable::PrivateLinkage,
547 NullConstantForBase, Twine());
548
549 CharUnits Align = std::max(Layout.getNonVirtualAlignment(),
550 DestPtr.getAlignment());
551 NullVariable->setAlignment(Align.getAsAlign());
552
553 Address SrcPtr = Address(CGF.EmitCastToVoidPtr(NullVariable), Align);
554
555 // Get and call the appropriate llvm.memcpy overload.
556 for (std::pair<CharUnits, CharUnits> Store : Stores) {
557 CharUnits StoreOffset = Store.first;
558 CharUnits StoreSize = Store.second;
559 llvm::Value *StoreSizeVal = CGF.CGM.getSize(StoreSize);
560 CGF.Builder.CreateMemCpy(
561 CGF.Builder.CreateConstInBoundsByteGEP(DestPtr, StoreOffset),
562 CGF.Builder.CreateConstInBoundsByteGEP(SrcPtr, StoreOffset),
563 StoreSizeVal);
564 }
565
566 // Otherwise, just memset the whole thing to zero. This is legal
567 // because in LLVM, all default initializers (other than the ones we just
568 // handled above) are guaranteed to have a bit pattern of all zeros.
569 } else {
570 for (std::pair<CharUnits, CharUnits> Store : Stores) {
571 CharUnits StoreOffset = Store.first;
572 CharUnits StoreSize = Store.second;
573 llvm::Value *StoreSizeVal = CGF.CGM.getSize(StoreSize);
574 CGF.Builder.CreateMemSet(
575 CGF.Builder.CreateConstInBoundsByteGEP(DestPtr, StoreOffset),
576 CGF.Builder.getInt8(0), StoreSizeVal);
577 }
578 }
579 }
580
581 void
EmitCXXConstructExpr(const CXXConstructExpr * E,AggValueSlot Dest)582 CodeGenFunction::EmitCXXConstructExpr(const CXXConstructExpr *E,
583 AggValueSlot Dest) {
584 assert(!Dest.isIgnored() && "Must have a destination!");
585 const CXXConstructorDecl *CD = E->getConstructor();
586
587 // If we require zero initialization before (or instead of) calling the
588 // constructor, as can be the case with a non-user-provided default
589 // constructor, emit the zero initialization now, unless destination is
590 // already zeroed.
591 if (E->requiresZeroInitialization() && !Dest.isZeroed()) {
592 switch (E->getConstructionKind()) {
593 case CXXConstructExpr::CK_Delegating:
594 case CXXConstructExpr::CK_Complete:
595 EmitNullInitialization(Dest.getAddress(), E->getType());
596 break;
597 case CXXConstructExpr::CK_VirtualBase:
598 case CXXConstructExpr::CK_NonVirtualBase:
599 EmitNullBaseClassInitialization(*this, Dest.getAddress(),
600 CD->getParent());
601 break;
602 }
603 }
604
605 // If this is a call to a trivial default constructor, do nothing.
606 if (CD->isTrivial() && CD->isDefaultConstructor())
607 return;
608
609 // Elide the constructor if we're constructing from a temporary.
610 // The temporary check is required because Sema sets this on NRVO
611 // returns.
612 if (getLangOpts().ElideConstructors && E->isElidable()) {
613 assert(getContext().hasSameUnqualifiedType(E->getType(),
614 E->getArg(0)->getType()));
615 if (E->getArg(0)->isTemporaryObject(getContext(), CD->getParent())) {
616 EmitAggExpr(E->getArg(0), Dest);
617 return;
618 }
619 }
620
621 if (const ArrayType *arrayType
622 = getContext().getAsArrayType(E->getType())) {
623 EmitCXXAggrConstructorCall(CD, arrayType, Dest.getAddress(), E,
624 Dest.isSanitizerChecked());
625 } else {
626 CXXCtorType Type = Ctor_Complete;
627 bool ForVirtualBase = false;
628 bool Delegating = false;
629
630 switch (E->getConstructionKind()) {
631 case CXXConstructExpr::CK_Delegating:
632 // We should be emitting a constructor; GlobalDecl will assert this
633 Type = CurGD.getCtorType();
634 Delegating = true;
635 break;
636
637 case CXXConstructExpr::CK_Complete:
638 Type = Ctor_Complete;
639 break;
640
641 case CXXConstructExpr::CK_VirtualBase:
642 ForVirtualBase = true;
643 LLVM_FALLTHROUGH;
644
645 case CXXConstructExpr::CK_NonVirtualBase:
646 Type = Ctor_Base;
647 }
648
649 // Call the constructor.
650 EmitCXXConstructorCall(CD, Type, ForVirtualBase, Delegating, Dest, E);
651 }
652 }
653
EmitSynthesizedCXXCopyCtor(Address Dest,Address Src,const Expr * Exp)654 void CodeGenFunction::EmitSynthesizedCXXCopyCtor(Address Dest, Address Src,
655 const Expr *Exp) {
656 if (const ExprWithCleanups *E = dyn_cast<ExprWithCleanups>(Exp))
657 Exp = E->getSubExpr();
658 assert(isa<CXXConstructExpr>(Exp) &&
659 "EmitSynthesizedCXXCopyCtor - unknown copy ctor expr");
660 const CXXConstructExpr* E = cast<CXXConstructExpr>(Exp);
661 const CXXConstructorDecl *CD = E->getConstructor();
662 RunCleanupsScope Scope(*this);
663
664 // If we require zero initialization before (or instead of) calling the
665 // constructor, as can be the case with a non-user-provided default
666 // constructor, emit the zero initialization now.
667 // FIXME. Do I still need this for a copy ctor synthesis?
668 if (E->requiresZeroInitialization())
669 EmitNullInitialization(Dest, E->getType());
670
671 assert(!getContext().getAsConstantArrayType(E->getType())
672 && "EmitSynthesizedCXXCopyCtor - Copied-in Array");
673 EmitSynthesizedCXXCopyCtorCall(CD, Dest, Src, E);
674 }
675
CalculateCookiePadding(CodeGenFunction & CGF,const CXXNewExpr * E)676 static CharUnits CalculateCookiePadding(CodeGenFunction &CGF,
677 const CXXNewExpr *E) {
678 if (!E->isArray())
679 return CharUnits::Zero();
680
681 // No cookie is required if the operator new[] being used is the
682 // reserved placement operator new[].
683 if (E->getOperatorNew()->isReservedGlobalPlacementOperator())
684 return CharUnits::Zero();
685
686 return CGF.CGM.getCXXABI().GetArrayCookieSize(E);
687 }
688
EmitCXXNewAllocSize(CodeGenFunction & CGF,const CXXNewExpr * e,unsigned minElements,llvm::Value * & numElements,llvm::Value * & sizeWithoutCookie)689 static llvm::Value *EmitCXXNewAllocSize(CodeGenFunction &CGF,
690 const CXXNewExpr *e,
691 unsigned minElements,
692 llvm::Value *&numElements,
693 llvm::Value *&sizeWithoutCookie) {
694 QualType type = e->getAllocatedType();
695
696 if (!e->isArray()) {
697 CharUnits typeSize = CGF.getContext().getTypeSizeInChars(type);
698 sizeWithoutCookie
699 = llvm::ConstantInt::get(CGF.SizeTy, typeSize.getQuantity());
700 return sizeWithoutCookie;
701 }
702
703 // The width of size_t.
704 unsigned sizeWidth = CGF.SizeTy->getBitWidth();
705
706 // Figure out the cookie size.
707 llvm::APInt cookieSize(sizeWidth,
708 CalculateCookiePadding(CGF, e).getQuantity());
709
710 // Emit the array size expression.
711 // We multiply the size of all dimensions for NumElements.
712 // e.g for 'int[2][3]', ElemType is 'int' and NumElements is 6.
713 numElements =
714 ConstantEmitter(CGF).tryEmitAbstract(*e->getArraySize(), e->getType());
715 if (!numElements)
716 numElements = CGF.EmitScalarExpr(*e->getArraySize());
717 assert(isa<llvm::IntegerType>(numElements->getType()));
718
719 // The number of elements can be have an arbitrary integer type;
720 // essentially, we need to multiply it by a constant factor, add a
721 // cookie size, and verify that the result is representable as a
722 // size_t. That's just a gloss, though, and it's wrong in one
723 // important way: if the count is negative, it's an error even if
724 // the cookie size would bring the total size >= 0.
725 bool isSigned
726 = (*e->getArraySize())->getType()->isSignedIntegerOrEnumerationType();
727 llvm::IntegerType *numElementsType
728 = cast<llvm::IntegerType>(numElements->getType());
729 unsigned numElementsWidth = numElementsType->getBitWidth();
730
731 // Compute the constant factor.
732 llvm::APInt arraySizeMultiplier(sizeWidth, 1);
733 while (const ConstantArrayType *CAT
734 = CGF.getContext().getAsConstantArrayType(type)) {
735 type = CAT->getElementType();
736 arraySizeMultiplier *= CAT->getSize();
737 }
738
739 CharUnits typeSize = CGF.getContext().getTypeSizeInChars(type);
740 llvm::APInt typeSizeMultiplier(sizeWidth, typeSize.getQuantity());
741 typeSizeMultiplier *= arraySizeMultiplier;
742
743 // This will be a size_t.
744 llvm::Value *size;
745
746 // If someone is doing 'new int[42]' there is no need to do a dynamic check.
747 // Don't bloat the -O0 code.
748 if (llvm::ConstantInt *numElementsC =
749 dyn_cast<llvm::ConstantInt>(numElements)) {
750 const llvm::APInt &count = numElementsC->getValue();
751
752 bool hasAnyOverflow = false;
753
754 // If 'count' was a negative number, it's an overflow.
755 if (isSigned && count.isNegative())
756 hasAnyOverflow = true;
757
758 // We want to do all this arithmetic in size_t. If numElements is
759 // wider than that, check whether it's already too big, and if so,
760 // overflow.
761 else if (numElementsWidth > sizeWidth &&
762 numElementsWidth - sizeWidth > count.countLeadingZeros())
763 hasAnyOverflow = true;
764
765 // Okay, compute a count at the right width.
766 llvm::APInt adjustedCount = count.zextOrTrunc(sizeWidth);
767
768 // If there is a brace-initializer, we cannot allocate fewer elements than
769 // there are initializers. If we do, that's treated like an overflow.
770 if (adjustedCount.ult(minElements))
771 hasAnyOverflow = true;
772
773 // Scale numElements by that. This might overflow, but we don't
774 // care because it only overflows if allocationSize does, too, and
775 // if that overflows then we shouldn't use this.
776 numElements = llvm::ConstantInt::get(CGF.SizeTy,
777 adjustedCount * arraySizeMultiplier);
778
779 // Compute the size before cookie, and track whether it overflowed.
780 bool overflow;
781 llvm::APInt allocationSize
782 = adjustedCount.umul_ov(typeSizeMultiplier, overflow);
783 hasAnyOverflow |= overflow;
784
785 // Add in the cookie, and check whether it's overflowed.
786 if (cookieSize != 0) {
787 // Save the current size without a cookie. This shouldn't be
788 // used if there was overflow.
789 sizeWithoutCookie = llvm::ConstantInt::get(CGF.SizeTy, allocationSize);
790
791 allocationSize = allocationSize.uadd_ov(cookieSize, overflow);
792 hasAnyOverflow |= overflow;
793 }
794
795 // On overflow, produce a -1 so operator new will fail.
796 if (hasAnyOverflow) {
797 size = llvm::Constant::getAllOnesValue(CGF.SizeTy);
798 } else {
799 size = llvm::ConstantInt::get(CGF.SizeTy, allocationSize);
800 }
801
802 // Otherwise, we might need to use the overflow intrinsics.
803 } else {
804 // There are up to five conditions we need to test for:
805 // 1) if isSigned, we need to check whether numElements is negative;
806 // 2) if numElementsWidth > sizeWidth, we need to check whether
807 // numElements is larger than something representable in size_t;
808 // 3) if minElements > 0, we need to check whether numElements is smaller
809 // than that.
810 // 4) we need to compute
811 // sizeWithoutCookie := numElements * typeSizeMultiplier
812 // and check whether it overflows; and
813 // 5) if we need a cookie, we need to compute
814 // size := sizeWithoutCookie + cookieSize
815 // and check whether it overflows.
816
817 llvm::Value *hasOverflow = nullptr;
818
819 // If numElementsWidth > sizeWidth, then one way or another, we're
820 // going to have to do a comparison for (2), and this happens to
821 // take care of (1), too.
822 if (numElementsWidth > sizeWidth) {
823 llvm::APInt threshold(numElementsWidth, 1);
824 threshold <<= sizeWidth;
825
826 llvm::Value *thresholdV
827 = llvm::ConstantInt::get(numElementsType, threshold);
828
829 hasOverflow = CGF.Builder.CreateICmpUGE(numElements, thresholdV);
830 numElements = CGF.Builder.CreateTrunc(numElements, CGF.SizeTy);
831
832 // Otherwise, if we're signed, we want to sext up to size_t.
833 } else if (isSigned) {
834 if (numElementsWidth < sizeWidth)
835 numElements = CGF.Builder.CreateSExt(numElements, CGF.SizeTy);
836
837 // If there's a non-1 type size multiplier, then we can do the
838 // signedness check at the same time as we do the multiply
839 // because a negative number times anything will cause an
840 // unsigned overflow. Otherwise, we have to do it here. But at least
841 // in this case, we can subsume the >= minElements check.
842 if (typeSizeMultiplier == 1)
843 hasOverflow = CGF.Builder.CreateICmpSLT(numElements,
844 llvm::ConstantInt::get(CGF.SizeTy, minElements));
845
846 // Otherwise, zext up to size_t if necessary.
847 } else if (numElementsWidth < sizeWidth) {
848 numElements = CGF.Builder.CreateZExt(numElements, CGF.SizeTy);
849 }
850
851 assert(numElements->getType() == CGF.SizeTy);
852
853 if (minElements) {
854 // Don't allow allocation of fewer elements than we have initializers.
855 if (!hasOverflow) {
856 hasOverflow = CGF.Builder.CreateICmpULT(numElements,
857 llvm::ConstantInt::get(CGF.SizeTy, minElements));
858 } else if (numElementsWidth > sizeWidth) {
859 // The other existing overflow subsumes this check.
860 // We do an unsigned comparison, since any signed value < -1 is
861 // taken care of either above or below.
862 hasOverflow = CGF.Builder.CreateOr(hasOverflow,
863 CGF.Builder.CreateICmpULT(numElements,
864 llvm::ConstantInt::get(CGF.SizeTy, minElements)));
865 }
866 }
867
868 size = numElements;
869
870 // Multiply by the type size if necessary. This multiplier
871 // includes all the factors for nested arrays.
872 //
873 // This step also causes numElements to be scaled up by the
874 // nested-array factor if necessary. Overflow on this computation
875 // can be ignored because the result shouldn't be used if
876 // allocation fails.
877 if (typeSizeMultiplier != 1) {
878 llvm::Function *umul_with_overflow
879 = CGF.CGM.getIntrinsic(llvm::Intrinsic::umul_with_overflow, CGF.SizeTy);
880
881 llvm::Value *tsmV =
882 llvm::ConstantInt::get(CGF.SizeTy, typeSizeMultiplier);
883 llvm::Value *result =
884 CGF.Builder.CreateCall(umul_with_overflow, {size, tsmV});
885
886 llvm::Value *overflowed = CGF.Builder.CreateExtractValue(result, 1);
887 if (hasOverflow)
888 hasOverflow = CGF.Builder.CreateOr(hasOverflow, overflowed);
889 else
890 hasOverflow = overflowed;
891
892 size = CGF.Builder.CreateExtractValue(result, 0);
893
894 // Also scale up numElements by the array size multiplier.
895 if (arraySizeMultiplier != 1) {
896 // If the base element type size is 1, then we can re-use the
897 // multiply we just did.
898 if (typeSize.isOne()) {
899 assert(arraySizeMultiplier == typeSizeMultiplier);
900 numElements = size;
901
902 // Otherwise we need a separate multiply.
903 } else {
904 llvm::Value *asmV =
905 llvm::ConstantInt::get(CGF.SizeTy, arraySizeMultiplier);
906 numElements = CGF.Builder.CreateMul(numElements, asmV);
907 }
908 }
909 } else {
910 // numElements doesn't need to be scaled.
911 assert(arraySizeMultiplier == 1);
912 }
913
914 // Add in the cookie size if necessary.
915 if (cookieSize != 0) {
916 sizeWithoutCookie = size;
917
918 llvm::Function *uadd_with_overflow
919 = CGF.CGM.getIntrinsic(llvm::Intrinsic::uadd_with_overflow, CGF.SizeTy);
920
921 llvm::Value *cookieSizeV = llvm::ConstantInt::get(CGF.SizeTy, cookieSize);
922 llvm::Value *result =
923 CGF.Builder.CreateCall(uadd_with_overflow, {size, cookieSizeV});
924
925 llvm::Value *overflowed = CGF.Builder.CreateExtractValue(result, 1);
926 if (hasOverflow)
927 hasOverflow = CGF.Builder.CreateOr(hasOverflow, overflowed);
928 else
929 hasOverflow = overflowed;
930
931 size = CGF.Builder.CreateExtractValue(result, 0);
932 }
933
934 // If we had any possibility of dynamic overflow, make a select to
935 // overwrite 'size' with an all-ones value, which should cause
936 // operator new to throw.
937 if (hasOverflow)
938 size = CGF.Builder.CreateSelect(hasOverflow,
939 llvm::Constant::getAllOnesValue(CGF.SizeTy),
940 size);
941 }
942
943 if (cookieSize == 0)
944 sizeWithoutCookie = size;
945 else
946 assert(sizeWithoutCookie && "didn't set sizeWithoutCookie?");
947
948 return size;
949 }
950
StoreAnyExprIntoOneUnit(CodeGenFunction & CGF,const Expr * Init,QualType AllocType,Address NewPtr,AggValueSlot::Overlap_t MayOverlap)951 static void StoreAnyExprIntoOneUnit(CodeGenFunction &CGF, const Expr *Init,
952 QualType AllocType, Address NewPtr,
953 AggValueSlot::Overlap_t MayOverlap) {
954 // FIXME: Refactor with EmitExprAsInit.
955 switch (CGF.getEvaluationKind(AllocType)) {
956 case TEK_Scalar:
957 CGF.EmitScalarInit(Init, nullptr,
958 CGF.MakeAddrLValue(NewPtr, AllocType), false);
959 return;
960 case TEK_Complex:
961 CGF.EmitComplexExprIntoLValue(Init, CGF.MakeAddrLValue(NewPtr, AllocType),
962 /*isInit*/ true);
963 return;
964 case TEK_Aggregate: {
965 AggValueSlot Slot
966 = AggValueSlot::forAddr(NewPtr, AllocType.getQualifiers(),
967 AggValueSlot::IsDestructed,
968 AggValueSlot::DoesNotNeedGCBarriers,
969 AggValueSlot::IsNotAliased,
970 MayOverlap, AggValueSlot::IsNotZeroed,
971 AggValueSlot::IsSanitizerChecked);
972 CGF.EmitAggExpr(Init, Slot);
973 return;
974 }
975 }
976 llvm_unreachable("bad evaluation kind");
977 }
978
EmitNewArrayInitializer(const CXXNewExpr * E,QualType ElementType,llvm::Type * ElementTy,Address BeginPtr,llvm::Value * NumElements,llvm::Value * AllocSizeWithoutCookie)979 void CodeGenFunction::EmitNewArrayInitializer(
980 const CXXNewExpr *E, QualType ElementType, llvm::Type *ElementTy,
981 Address BeginPtr, llvm::Value *NumElements,
982 llvm::Value *AllocSizeWithoutCookie) {
983 // If we have a type with trivial initialization and no initializer,
984 // there's nothing to do.
985 if (!E->hasInitializer())
986 return;
987
988 Address CurPtr = BeginPtr;
989
990 unsigned InitListElements = 0;
991
992 const Expr *Init = E->getInitializer();
993 Address EndOfInit = Address::invalid();
994 QualType::DestructionKind DtorKind = ElementType.isDestructedType();
995 EHScopeStack::stable_iterator Cleanup;
996 llvm::Instruction *CleanupDominator = nullptr;
997
998 CharUnits ElementSize = getContext().getTypeSizeInChars(ElementType);
999 CharUnits ElementAlign =
1000 BeginPtr.getAlignment().alignmentOfArrayElement(ElementSize);
1001
1002 // Attempt to perform zero-initialization using memset.
1003 auto TryMemsetInitialization = [&]() -> bool {
1004 // FIXME: If the type is a pointer-to-data-member under the Itanium ABI,
1005 // we can initialize with a memset to -1.
1006 if (!CGM.getTypes().isZeroInitializable(ElementType))
1007 return false;
1008
1009 // Optimization: since zero initialization will just set the memory
1010 // to all zeroes, generate a single memset to do it in one shot.
1011
1012 // Subtract out the size of any elements we've already initialized.
1013 auto *RemainingSize = AllocSizeWithoutCookie;
1014 if (InitListElements) {
1015 // We know this can't overflow; we check this when doing the allocation.
1016 auto *InitializedSize = llvm::ConstantInt::get(
1017 RemainingSize->getType(),
1018 getContext().getTypeSizeInChars(ElementType).getQuantity() *
1019 InitListElements);
1020 RemainingSize = Builder.CreateSub(RemainingSize, InitializedSize);
1021 }
1022
1023 // Create the memset.
1024 Builder.CreateMemSet(CurPtr, Builder.getInt8(0), RemainingSize, false);
1025 return true;
1026 };
1027
1028 // If the initializer is an initializer list, first do the explicit elements.
1029 if (const InitListExpr *ILE = dyn_cast<InitListExpr>(Init)) {
1030 // Initializing from a (braced) string literal is a special case; the init
1031 // list element does not initialize a (single) array element.
1032 if (ILE->isStringLiteralInit()) {
1033 // Initialize the initial portion of length equal to that of the string
1034 // literal. The allocation must be for at least this much; we emitted a
1035 // check for that earlier.
1036 AggValueSlot Slot =
1037 AggValueSlot::forAddr(CurPtr, ElementType.getQualifiers(),
1038 AggValueSlot::IsDestructed,
1039 AggValueSlot::DoesNotNeedGCBarriers,
1040 AggValueSlot::IsNotAliased,
1041 AggValueSlot::DoesNotOverlap,
1042 AggValueSlot::IsNotZeroed,
1043 AggValueSlot::IsSanitizerChecked);
1044 EmitAggExpr(ILE->getInit(0), Slot);
1045
1046 // Move past these elements.
1047 InitListElements =
1048 cast<ConstantArrayType>(ILE->getType()->getAsArrayTypeUnsafe())
1049 ->getSize().getZExtValue();
1050 CurPtr =
1051 Address(Builder.CreateInBoundsGEP(CurPtr.getPointer(),
1052 Builder.getSize(InitListElements),
1053 "string.init.end"),
1054 CurPtr.getAlignment().alignmentAtOffset(InitListElements *
1055 ElementSize));
1056
1057 // Zero out the rest, if any remain.
1058 llvm::ConstantInt *ConstNum = dyn_cast<llvm::ConstantInt>(NumElements);
1059 if (!ConstNum || !ConstNum->equalsInt(InitListElements)) {
1060 bool OK = TryMemsetInitialization();
1061 (void)OK;
1062 assert(OK && "couldn't memset character type?");
1063 }
1064 return;
1065 }
1066
1067 InitListElements = ILE->getNumInits();
1068
1069 // If this is a multi-dimensional array new, we will initialize multiple
1070 // elements with each init list element.
1071 QualType AllocType = E->getAllocatedType();
1072 if (const ConstantArrayType *CAT = dyn_cast_or_null<ConstantArrayType>(
1073 AllocType->getAsArrayTypeUnsafe())) {
1074 ElementTy = ConvertTypeForMem(AllocType);
1075 CurPtr = Builder.CreateElementBitCast(CurPtr, ElementTy);
1076 InitListElements *= getContext().getConstantArrayElementCount(CAT);
1077 }
1078
1079 // Enter a partial-destruction Cleanup if necessary.
1080 if (needsEHCleanup(DtorKind)) {
1081 // In principle we could tell the Cleanup where we are more
1082 // directly, but the control flow can get so varied here that it
1083 // would actually be quite complex. Therefore we go through an
1084 // alloca.
1085 EndOfInit = CreateTempAlloca(BeginPtr.getType(), getPointerAlign(),
1086 "array.init.end");
1087 CleanupDominator = Builder.CreateStore(BeginPtr.getPointer(), EndOfInit);
1088 pushIrregularPartialArrayCleanup(BeginPtr.getPointer(), EndOfInit,
1089 ElementType, ElementAlign,
1090 getDestroyer(DtorKind));
1091 Cleanup = EHStack.stable_begin();
1092 }
1093
1094 CharUnits StartAlign = CurPtr.getAlignment();
1095 for (unsigned i = 0, e = ILE->getNumInits(); i != e; ++i) {
1096 // Tell the cleanup that it needs to destroy up to this
1097 // element. TODO: some of these stores can be trivially
1098 // observed to be unnecessary.
1099 if (EndOfInit.isValid()) {
1100 auto FinishedPtr =
1101 Builder.CreateBitCast(CurPtr.getPointer(), BeginPtr.getType());
1102 Builder.CreateStore(FinishedPtr, EndOfInit);
1103 }
1104 // FIXME: If the last initializer is an incomplete initializer list for
1105 // an array, and we have an array filler, we can fold together the two
1106 // initialization loops.
1107 StoreAnyExprIntoOneUnit(*this, ILE->getInit(i),
1108 ILE->getInit(i)->getType(), CurPtr,
1109 AggValueSlot::DoesNotOverlap);
1110 CurPtr = Address(Builder.CreateInBoundsGEP(CurPtr.getPointer(),
1111 Builder.getSize(1),
1112 "array.exp.next"),
1113 StartAlign.alignmentAtOffset((i + 1) * ElementSize));
1114 }
1115
1116 // The remaining elements are filled with the array filler expression.
1117 Init = ILE->getArrayFiller();
1118
1119 // Extract the initializer for the individual array elements by pulling
1120 // out the array filler from all the nested initializer lists. This avoids
1121 // generating a nested loop for the initialization.
1122 while (Init && Init->getType()->isConstantArrayType()) {
1123 auto *SubILE = dyn_cast<InitListExpr>(Init);
1124 if (!SubILE)
1125 break;
1126 assert(SubILE->getNumInits() == 0 && "explicit inits in array filler?");
1127 Init = SubILE->getArrayFiller();
1128 }
1129
1130 // Switch back to initializing one base element at a time.
1131 CurPtr = Builder.CreateBitCast(CurPtr, BeginPtr.getType());
1132 }
1133
1134 // If all elements have already been initialized, skip any further
1135 // initialization.
1136 llvm::ConstantInt *ConstNum = dyn_cast<llvm::ConstantInt>(NumElements);
1137 if (ConstNum && ConstNum->getZExtValue() <= InitListElements) {
1138 // If there was a Cleanup, deactivate it.
1139 if (CleanupDominator)
1140 DeactivateCleanupBlock(Cleanup, CleanupDominator);
1141 return;
1142 }
1143
1144 assert(Init && "have trailing elements to initialize but no initializer");
1145
1146 // If this is a constructor call, try to optimize it out, and failing that
1147 // emit a single loop to initialize all remaining elements.
1148 if (const CXXConstructExpr *CCE = dyn_cast<CXXConstructExpr>(Init)) {
1149 CXXConstructorDecl *Ctor = CCE->getConstructor();
1150 if (Ctor->isTrivial()) {
1151 // If new expression did not specify value-initialization, then there
1152 // is no initialization.
1153 if (!CCE->requiresZeroInitialization() || Ctor->getParent()->isEmpty())
1154 return;
1155
1156 if (TryMemsetInitialization())
1157 return;
1158 }
1159
1160 // Store the new Cleanup position for irregular Cleanups.
1161 //
1162 // FIXME: Share this cleanup with the constructor call emission rather than
1163 // having it create a cleanup of its own.
1164 if (EndOfInit.isValid())
1165 Builder.CreateStore(CurPtr.getPointer(), EndOfInit);
1166
1167 // Emit a constructor call loop to initialize the remaining elements.
1168 if (InitListElements)
1169 NumElements = Builder.CreateSub(
1170 NumElements,
1171 llvm::ConstantInt::get(NumElements->getType(), InitListElements));
1172 EmitCXXAggrConstructorCall(Ctor, NumElements, CurPtr, CCE,
1173 /*NewPointerIsChecked*/true,
1174 CCE->requiresZeroInitialization());
1175 return;
1176 }
1177
1178 // If this is value-initialization, we can usually use memset.
1179 ImplicitValueInitExpr IVIE(ElementType);
1180 if (isa<ImplicitValueInitExpr>(Init)) {
1181 if (TryMemsetInitialization())
1182 return;
1183
1184 // Switch to an ImplicitValueInitExpr for the element type. This handles
1185 // only one case: multidimensional array new of pointers to members. In
1186 // all other cases, we already have an initializer for the array element.
1187 Init = &IVIE;
1188 }
1189
1190 // At this point we should have found an initializer for the individual
1191 // elements of the array.
1192 assert(getContext().hasSameUnqualifiedType(ElementType, Init->getType()) &&
1193 "got wrong type of element to initialize");
1194
1195 // If we have an empty initializer list, we can usually use memset.
1196 if (auto *ILE = dyn_cast<InitListExpr>(Init))
1197 if (ILE->getNumInits() == 0 && TryMemsetInitialization())
1198 return;
1199
1200 // If we have a struct whose every field is value-initialized, we can
1201 // usually use memset.
1202 if (auto *ILE = dyn_cast<InitListExpr>(Init)) {
1203 if (const RecordType *RType = ILE->getType()->getAs<RecordType>()) {
1204 if (RType->getDecl()->isStruct()) {
1205 unsigned NumElements = 0;
1206 if (auto *CXXRD = dyn_cast<CXXRecordDecl>(RType->getDecl()))
1207 NumElements = CXXRD->getNumBases();
1208 for (auto *Field : RType->getDecl()->fields())
1209 if (!Field->isUnnamedBitfield())
1210 ++NumElements;
1211 // FIXME: Recurse into nested InitListExprs.
1212 if (ILE->getNumInits() == NumElements)
1213 for (unsigned i = 0, e = ILE->getNumInits(); i != e; ++i)
1214 if (!isa<ImplicitValueInitExpr>(ILE->getInit(i)))
1215 --NumElements;
1216 if (ILE->getNumInits() == NumElements && TryMemsetInitialization())
1217 return;
1218 }
1219 }
1220 }
1221
1222 // Create the loop blocks.
1223 llvm::BasicBlock *EntryBB = Builder.GetInsertBlock();
1224 llvm::BasicBlock *LoopBB = createBasicBlock("new.loop");
1225 llvm::BasicBlock *ContBB = createBasicBlock("new.loop.end");
1226
1227 // Find the end of the array, hoisted out of the loop.
1228 llvm::Value *EndPtr =
1229 Builder.CreateInBoundsGEP(BeginPtr.getPointer(), NumElements, "array.end");
1230
1231 // If the number of elements isn't constant, we have to now check if there is
1232 // anything left to initialize.
1233 if (!ConstNum) {
1234 llvm::Value *IsEmpty =
1235 Builder.CreateICmpEQ(CurPtr.getPointer(), EndPtr, "array.isempty");
1236 Builder.CreateCondBr(IsEmpty, ContBB, LoopBB);
1237 }
1238
1239 // Enter the loop.
1240 EmitBlock(LoopBB);
1241
1242 // Set up the current-element phi.
1243 llvm::PHINode *CurPtrPhi =
1244 Builder.CreatePHI(CurPtr.getType(), 2, "array.cur");
1245 CurPtrPhi->addIncoming(CurPtr.getPointer(), EntryBB);
1246
1247 CurPtr = Address(CurPtrPhi, ElementAlign);
1248
1249 // Store the new Cleanup position for irregular Cleanups.
1250 if (EndOfInit.isValid())
1251 Builder.CreateStore(CurPtr.getPointer(), EndOfInit);
1252
1253 // Enter a partial-destruction Cleanup if necessary.
1254 if (!CleanupDominator && needsEHCleanup(DtorKind)) {
1255 pushRegularPartialArrayCleanup(BeginPtr.getPointer(), CurPtr.getPointer(),
1256 ElementType, ElementAlign,
1257 getDestroyer(DtorKind));
1258 Cleanup = EHStack.stable_begin();
1259 CleanupDominator = Builder.CreateUnreachable();
1260 }
1261
1262 // Emit the initializer into this element.
1263 StoreAnyExprIntoOneUnit(*this, Init, Init->getType(), CurPtr,
1264 AggValueSlot::DoesNotOverlap);
1265
1266 // Leave the Cleanup if we entered one.
1267 if (CleanupDominator) {
1268 DeactivateCleanupBlock(Cleanup, CleanupDominator);
1269 CleanupDominator->eraseFromParent();
1270 }
1271
1272 // Advance to the next element by adjusting the pointer type as necessary.
1273 llvm::Value *NextPtr =
1274 Builder.CreateConstInBoundsGEP1_32(ElementTy, CurPtr.getPointer(), 1,
1275 "array.next");
1276
1277 // Check whether we've gotten to the end of the array and, if so,
1278 // exit the loop.
1279 llvm::Value *IsEnd = Builder.CreateICmpEQ(NextPtr, EndPtr, "array.atend");
1280 Builder.CreateCondBr(IsEnd, ContBB, LoopBB);
1281 CurPtrPhi->addIncoming(NextPtr, Builder.GetInsertBlock());
1282
1283 EmitBlock(ContBB);
1284 }
1285
EmitNewInitializer(CodeGenFunction & CGF,const CXXNewExpr * E,QualType ElementType,llvm::Type * ElementTy,Address NewPtr,llvm::Value * NumElements,llvm::Value * AllocSizeWithoutCookie)1286 static void EmitNewInitializer(CodeGenFunction &CGF, const CXXNewExpr *E,
1287 QualType ElementType, llvm::Type *ElementTy,
1288 Address NewPtr, llvm::Value *NumElements,
1289 llvm::Value *AllocSizeWithoutCookie) {
1290 ApplyDebugLocation DL(CGF, E);
1291 if (E->isArray())
1292 CGF.EmitNewArrayInitializer(E, ElementType, ElementTy, NewPtr, NumElements,
1293 AllocSizeWithoutCookie);
1294 else if (const Expr *Init = E->getInitializer())
1295 StoreAnyExprIntoOneUnit(CGF, Init, E->getAllocatedType(), NewPtr,
1296 AggValueSlot::DoesNotOverlap);
1297 }
1298
1299 /// Emit a call to an operator new or operator delete function, as implicitly
1300 /// created by new-expressions and delete-expressions.
EmitNewDeleteCall(CodeGenFunction & CGF,const FunctionDecl * CalleeDecl,const FunctionProtoType * CalleeType,const CallArgList & Args)1301 static RValue EmitNewDeleteCall(CodeGenFunction &CGF,
1302 const FunctionDecl *CalleeDecl,
1303 const FunctionProtoType *CalleeType,
1304 const CallArgList &Args) {
1305 llvm::CallBase *CallOrInvoke;
1306 llvm::Constant *CalleePtr = CGF.CGM.GetAddrOfFunction(CalleeDecl);
1307 CGCallee Callee = CGCallee::forDirect(CalleePtr, GlobalDecl(CalleeDecl));
1308 RValue RV =
1309 CGF.EmitCall(CGF.CGM.getTypes().arrangeFreeFunctionCall(
1310 Args, CalleeType, /*ChainCall=*/false),
1311 Callee, ReturnValueSlot(), Args, &CallOrInvoke);
1312
1313 /// C++1y [expr.new]p10:
1314 /// [In a new-expression,] an implementation is allowed to omit a call
1315 /// to a replaceable global allocation function.
1316 ///
1317 /// We model such elidable calls with the 'builtin' attribute.
1318 llvm::Function *Fn = dyn_cast<llvm::Function>(CalleePtr);
1319 if (CalleeDecl->isReplaceableGlobalAllocationFunction() &&
1320 Fn && Fn->hasFnAttribute(llvm::Attribute::NoBuiltin)) {
1321 CallOrInvoke->addAttribute(llvm::AttributeList::FunctionIndex,
1322 llvm::Attribute::Builtin);
1323 }
1324
1325 return RV;
1326 }
1327
EmitBuiltinNewDeleteCall(const FunctionProtoType * Type,const CallExpr * TheCall,bool IsDelete)1328 RValue CodeGenFunction::EmitBuiltinNewDeleteCall(const FunctionProtoType *Type,
1329 const CallExpr *TheCall,
1330 bool IsDelete) {
1331 CallArgList Args;
1332 EmitCallArgs(Args, Type, TheCall->arguments());
1333 // Find the allocation or deallocation function that we're calling.
1334 ASTContext &Ctx = getContext();
1335 DeclarationName Name = Ctx.DeclarationNames
1336 .getCXXOperatorName(IsDelete ? OO_Delete : OO_New);
1337
1338 for (auto *Decl : Ctx.getTranslationUnitDecl()->lookup(Name))
1339 if (auto *FD = dyn_cast<FunctionDecl>(Decl))
1340 if (Ctx.hasSameType(FD->getType(), QualType(Type, 0)))
1341 return EmitNewDeleteCall(*this, FD, Type, Args);
1342 llvm_unreachable("predeclared global operator new/delete is missing");
1343 }
1344
1345 namespace {
1346 /// The parameters to pass to a usual operator delete.
1347 struct UsualDeleteParams {
1348 bool DestroyingDelete = false;
1349 bool Size = false;
1350 bool Alignment = false;
1351 };
1352 }
1353
getUsualDeleteParams(const FunctionDecl * FD)1354 static UsualDeleteParams getUsualDeleteParams(const FunctionDecl *FD) {
1355 UsualDeleteParams Params;
1356
1357 const FunctionProtoType *FPT = FD->getType()->castAs<FunctionProtoType>();
1358 auto AI = FPT->param_type_begin(), AE = FPT->param_type_end();
1359
1360 // The first argument is always a void*.
1361 ++AI;
1362
1363 // The next parameter may be a std::destroying_delete_t.
1364 if (FD->isDestroyingOperatorDelete()) {
1365 Params.DestroyingDelete = true;
1366 assert(AI != AE);
1367 ++AI;
1368 }
1369
1370 // Figure out what other parameters we should be implicitly passing.
1371 if (AI != AE && (*AI)->isIntegerType()) {
1372 Params.Size = true;
1373 ++AI;
1374 }
1375
1376 if (AI != AE && (*AI)->isAlignValT()) {
1377 Params.Alignment = true;
1378 ++AI;
1379 }
1380
1381 assert(AI == AE && "unexpected usual deallocation function parameter");
1382 return Params;
1383 }
1384
1385 namespace {
1386 /// A cleanup to call the given 'operator delete' function upon abnormal
1387 /// exit from a new expression. Templated on a traits type that deals with
1388 /// ensuring that the arguments dominate the cleanup if necessary.
1389 template<typename Traits>
1390 class CallDeleteDuringNew final : public EHScopeStack::Cleanup {
1391 /// Type used to hold llvm::Value*s.
1392 typedef typename Traits::ValueTy ValueTy;
1393 /// Type used to hold RValues.
1394 typedef typename Traits::RValueTy RValueTy;
1395 struct PlacementArg {
1396 RValueTy ArgValue;
1397 QualType ArgType;
1398 };
1399
1400 unsigned NumPlacementArgs : 31;
1401 unsigned PassAlignmentToPlacementDelete : 1;
1402 const FunctionDecl *OperatorDelete;
1403 ValueTy Ptr;
1404 ValueTy AllocSize;
1405 CharUnits AllocAlign;
1406
getPlacementArgs()1407 PlacementArg *getPlacementArgs() {
1408 return reinterpret_cast<PlacementArg *>(this + 1);
1409 }
1410
1411 public:
getExtraSize(size_t NumPlacementArgs)1412 static size_t getExtraSize(size_t NumPlacementArgs) {
1413 return NumPlacementArgs * sizeof(PlacementArg);
1414 }
1415
CallDeleteDuringNew(size_t NumPlacementArgs,const FunctionDecl * OperatorDelete,ValueTy Ptr,ValueTy AllocSize,bool PassAlignmentToPlacementDelete,CharUnits AllocAlign)1416 CallDeleteDuringNew(size_t NumPlacementArgs,
1417 const FunctionDecl *OperatorDelete, ValueTy Ptr,
1418 ValueTy AllocSize, bool PassAlignmentToPlacementDelete,
1419 CharUnits AllocAlign)
1420 : NumPlacementArgs(NumPlacementArgs),
1421 PassAlignmentToPlacementDelete(PassAlignmentToPlacementDelete),
1422 OperatorDelete(OperatorDelete), Ptr(Ptr), AllocSize(AllocSize),
1423 AllocAlign(AllocAlign) {}
1424
setPlacementArg(unsigned I,RValueTy Arg,QualType Type)1425 void setPlacementArg(unsigned I, RValueTy Arg, QualType Type) {
1426 assert(I < NumPlacementArgs && "index out of range");
1427 getPlacementArgs()[I] = {Arg, Type};
1428 }
1429
Emit(CodeGenFunction & CGF,Flags flags)1430 void Emit(CodeGenFunction &CGF, Flags flags) override {
1431 const auto *FPT = OperatorDelete->getType()->castAs<FunctionProtoType>();
1432 CallArgList DeleteArgs;
1433
1434 // The first argument is always a void* (or C* for a destroying operator
1435 // delete for class type C).
1436 DeleteArgs.add(Traits::get(CGF, Ptr), FPT->getParamType(0));
1437
1438 // Figure out what other parameters we should be implicitly passing.
1439 UsualDeleteParams Params;
1440 if (NumPlacementArgs) {
1441 // A placement deallocation function is implicitly passed an alignment
1442 // if the placement allocation function was, but is never passed a size.
1443 Params.Alignment = PassAlignmentToPlacementDelete;
1444 } else {
1445 // For a non-placement new-expression, 'operator delete' can take a
1446 // size and/or an alignment if it has the right parameters.
1447 Params = getUsualDeleteParams(OperatorDelete);
1448 }
1449
1450 assert(!Params.DestroyingDelete &&
1451 "should not call destroying delete in a new-expression");
1452
1453 // The second argument can be a std::size_t (for non-placement delete).
1454 if (Params.Size)
1455 DeleteArgs.add(Traits::get(CGF, AllocSize),
1456 CGF.getContext().getSizeType());
1457
1458 // The next (second or third) argument can be a std::align_val_t, which
1459 // is an enum whose underlying type is std::size_t.
1460 // FIXME: Use the right type as the parameter type. Note that in a call
1461 // to operator delete(size_t, ...), we may not have it available.
1462 if (Params.Alignment)
1463 DeleteArgs.add(RValue::get(llvm::ConstantInt::get(
1464 CGF.SizeTy, AllocAlign.getQuantity())),
1465 CGF.getContext().getSizeType());
1466
1467 // Pass the rest of the arguments, which must match exactly.
1468 for (unsigned I = 0; I != NumPlacementArgs; ++I) {
1469 auto Arg = getPlacementArgs()[I];
1470 DeleteArgs.add(Traits::get(CGF, Arg.ArgValue), Arg.ArgType);
1471 }
1472
1473 // Call 'operator delete'.
1474 EmitNewDeleteCall(CGF, OperatorDelete, FPT, DeleteArgs);
1475 }
1476 };
1477 }
1478
1479 /// Enter a cleanup to call 'operator delete' if the initializer in a
1480 /// new-expression throws.
EnterNewDeleteCleanup(CodeGenFunction & CGF,const CXXNewExpr * E,Address NewPtr,llvm::Value * AllocSize,CharUnits AllocAlign,const CallArgList & NewArgs)1481 static void EnterNewDeleteCleanup(CodeGenFunction &CGF,
1482 const CXXNewExpr *E,
1483 Address NewPtr,
1484 llvm::Value *AllocSize,
1485 CharUnits AllocAlign,
1486 const CallArgList &NewArgs) {
1487 unsigned NumNonPlacementArgs = E->passAlignment() ? 2 : 1;
1488
1489 // If we're not inside a conditional branch, then the cleanup will
1490 // dominate and we can do the easier (and more efficient) thing.
1491 if (!CGF.isInConditionalBranch()) {
1492 struct DirectCleanupTraits {
1493 typedef llvm::Value *ValueTy;
1494 typedef RValue RValueTy;
1495 static RValue get(CodeGenFunction &, ValueTy V) { return RValue::get(V); }
1496 static RValue get(CodeGenFunction &, RValueTy V) { return V; }
1497 };
1498
1499 typedef CallDeleteDuringNew<DirectCleanupTraits> DirectCleanup;
1500
1501 DirectCleanup *Cleanup = CGF.EHStack
1502 .pushCleanupWithExtra<DirectCleanup>(EHCleanup,
1503 E->getNumPlacementArgs(),
1504 E->getOperatorDelete(),
1505 NewPtr.getPointer(),
1506 AllocSize,
1507 E->passAlignment(),
1508 AllocAlign);
1509 for (unsigned I = 0, N = E->getNumPlacementArgs(); I != N; ++I) {
1510 auto &Arg = NewArgs[I + NumNonPlacementArgs];
1511 Cleanup->setPlacementArg(I, Arg.getRValue(CGF), Arg.Ty);
1512 }
1513
1514 return;
1515 }
1516
1517 // Otherwise, we need to save all this stuff.
1518 DominatingValue<RValue>::saved_type SavedNewPtr =
1519 DominatingValue<RValue>::save(CGF, RValue::get(NewPtr.getPointer()));
1520 DominatingValue<RValue>::saved_type SavedAllocSize =
1521 DominatingValue<RValue>::save(CGF, RValue::get(AllocSize));
1522
1523 struct ConditionalCleanupTraits {
1524 typedef DominatingValue<RValue>::saved_type ValueTy;
1525 typedef DominatingValue<RValue>::saved_type RValueTy;
1526 static RValue get(CodeGenFunction &CGF, ValueTy V) {
1527 return V.restore(CGF);
1528 }
1529 };
1530 typedef CallDeleteDuringNew<ConditionalCleanupTraits> ConditionalCleanup;
1531
1532 ConditionalCleanup *Cleanup = CGF.EHStack
1533 .pushCleanupWithExtra<ConditionalCleanup>(EHCleanup,
1534 E->getNumPlacementArgs(),
1535 E->getOperatorDelete(),
1536 SavedNewPtr,
1537 SavedAllocSize,
1538 E->passAlignment(),
1539 AllocAlign);
1540 for (unsigned I = 0, N = E->getNumPlacementArgs(); I != N; ++I) {
1541 auto &Arg = NewArgs[I + NumNonPlacementArgs];
1542 Cleanup->setPlacementArg(
1543 I, DominatingValue<RValue>::save(CGF, Arg.getRValue(CGF)), Arg.Ty);
1544 }
1545
1546 CGF.initFullExprCleanup();
1547 }
1548
EmitCXXNewExpr(const CXXNewExpr * E)1549 llvm::Value *CodeGenFunction::EmitCXXNewExpr(const CXXNewExpr *E) {
1550 // The element type being allocated.
1551 QualType allocType = getContext().getBaseElementType(E->getAllocatedType());
1552
1553 // 1. Build a call to the allocation function.
1554 FunctionDecl *allocator = E->getOperatorNew();
1555
1556 // If there is a brace-initializer, cannot allocate fewer elements than inits.
1557 unsigned minElements = 0;
1558 if (E->isArray() && E->hasInitializer()) {
1559 const InitListExpr *ILE = dyn_cast<InitListExpr>(E->getInitializer());
1560 if (ILE && ILE->isStringLiteralInit())
1561 minElements =
1562 cast<ConstantArrayType>(ILE->getType()->getAsArrayTypeUnsafe())
1563 ->getSize().getZExtValue();
1564 else if (ILE)
1565 minElements = ILE->getNumInits();
1566 }
1567
1568 llvm::Value *numElements = nullptr;
1569 llvm::Value *allocSizeWithoutCookie = nullptr;
1570 llvm::Value *allocSize =
1571 EmitCXXNewAllocSize(*this, E, minElements, numElements,
1572 allocSizeWithoutCookie);
1573 CharUnits allocAlign = getContext().getPreferredTypeAlignInChars(allocType);
1574
1575 // Emit the allocation call. If the allocator is a global placement
1576 // operator, just "inline" it directly.
1577 Address allocation = Address::invalid();
1578 CallArgList allocatorArgs;
1579 if (allocator->isReservedGlobalPlacementOperator()) {
1580 assert(E->getNumPlacementArgs() == 1);
1581 const Expr *arg = *E->placement_arguments().begin();
1582
1583 LValueBaseInfo BaseInfo;
1584 allocation = EmitPointerWithAlignment(arg, &BaseInfo);
1585
1586 // The pointer expression will, in many cases, be an opaque void*.
1587 // In these cases, discard the computed alignment and use the
1588 // formal alignment of the allocated type.
1589 if (BaseInfo.getAlignmentSource() != AlignmentSource::Decl)
1590 allocation = Address(allocation.getPointer(), allocAlign);
1591
1592 // Set up allocatorArgs for the call to operator delete if it's not
1593 // the reserved global operator.
1594 if (E->getOperatorDelete() &&
1595 !E->getOperatorDelete()->isReservedGlobalPlacementOperator()) {
1596 allocatorArgs.add(RValue::get(allocSize), getContext().getSizeType());
1597 allocatorArgs.add(RValue::get(allocation.getPointer()), arg->getType());
1598 }
1599
1600 } else {
1601 const FunctionProtoType *allocatorType =
1602 allocator->getType()->castAs<FunctionProtoType>();
1603 unsigned ParamsToSkip = 0;
1604
1605 // The allocation size is the first argument.
1606 QualType sizeType = getContext().getSizeType();
1607 allocatorArgs.add(RValue::get(allocSize), sizeType);
1608 ++ParamsToSkip;
1609
1610 if (allocSize != allocSizeWithoutCookie) {
1611 CharUnits cookieAlign = getSizeAlign(); // FIXME: Ask the ABI.
1612 allocAlign = std::max(allocAlign, cookieAlign);
1613 }
1614
1615 // The allocation alignment may be passed as the second argument.
1616 if (E->passAlignment()) {
1617 QualType AlignValT = sizeType;
1618 if (allocatorType->getNumParams() > 1) {
1619 AlignValT = allocatorType->getParamType(1);
1620 assert(getContext().hasSameUnqualifiedType(
1621 AlignValT->castAs<EnumType>()->getDecl()->getIntegerType(),
1622 sizeType) &&
1623 "wrong type for alignment parameter");
1624 ++ParamsToSkip;
1625 } else {
1626 // Corner case, passing alignment to 'operator new(size_t, ...)'.
1627 assert(allocator->isVariadic() && "can't pass alignment to allocator");
1628 }
1629 allocatorArgs.add(
1630 RValue::get(llvm::ConstantInt::get(SizeTy, allocAlign.getQuantity())),
1631 AlignValT);
1632 }
1633
1634 // FIXME: Why do we not pass a CalleeDecl here?
1635 EmitCallArgs(allocatorArgs, allocatorType, E->placement_arguments(),
1636 /*AC*/AbstractCallee(), /*ParamsToSkip*/ParamsToSkip);
1637
1638 RValue RV =
1639 EmitNewDeleteCall(*this, allocator, allocatorType, allocatorArgs);
1640
1641 // Set !heapallocsite metadata on the call to operator new.
1642 if (getDebugInfo())
1643 if (auto *newCall = dyn_cast<llvm::CallBase>(RV.getScalarVal()))
1644 getDebugInfo()->addHeapAllocSiteMetadata(newCall, allocType,
1645 E->getExprLoc());
1646
1647 // If this was a call to a global replaceable allocation function that does
1648 // not take an alignment argument, the allocator is known to produce
1649 // storage that's suitably aligned for any object that fits, up to a known
1650 // threshold. Otherwise assume it's suitably aligned for the allocated type.
1651 CharUnits allocationAlign = allocAlign;
1652 if (!E->passAlignment() &&
1653 allocator->isReplaceableGlobalAllocationFunction()) {
1654 unsigned AllocatorAlign = llvm::PowerOf2Floor(std::min<uint64_t>(
1655 Target.getNewAlign(), getContext().getTypeSize(allocType)));
1656 allocationAlign = std::max(
1657 allocationAlign, getContext().toCharUnitsFromBits(AllocatorAlign));
1658 }
1659
1660 allocation = Address(RV.getScalarVal(), allocationAlign);
1661 }
1662
1663 // Emit a null check on the allocation result if the allocation
1664 // function is allowed to return null (because it has a non-throwing
1665 // exception spec or is the reserved placement new) and we have an
1666 // interesting initializer will be running sanitizers on the initialization.
1667 bool nullCheck = E->shouldNullCheckAllocation() &&
1668 (!allocType.isPODType(getContext()) || E->hasInitializer() ||
1669 sanitizePerformTypeCheck());
1670
1671 llvm::BasicBlock *nullCheckBB = nullptr;
1672 llvm::BasicBlock *contBB = nullptr;
1673
1674 // The null-check means that the initializer is conditionally
1675 // evaluated.
1676 ConditionalEvaluation conditional(*this);
1677
1678 if (nullCheck) {
1679 conditional.begin(*this);
1680
1681 nullCheckBB = Builder.GetInsertBlock();
1682 llvm::BasicBlock *notNullBB = createBasicBlock("new.notnull");
1683 contBB = createBasicBlock("new.cont");
1684
1685 llvm::Value *isNull =
1686 Builder.CreateIsNull(allocation.getPointer(), "new.isnull");
1687 Builder.CreateCondBr(isNull, contBB, notNullBB);
1688 EmitBlock(notNullBB);
1689 }
1690
1691 // If there's an operator delete, enter a cleanup to call it if an
1692 // exception is thrown.
1693 EHScopeStack::stable_iterator operatorDeleteCleanup;
1694 llvm::Instruction *cleanupDominator = nullptr;
1695 if (E->getOperatorDelete() &&
1696 !E->getOperatorDelete()->isReservedGlobalPlacementOperator()) {
1697 EnterNewDeleteCleanup(*this, E, allocation, allocSize, allocAlign,
1698 allocatorArgs);
1699 operatorDeleteCleanup = EHStack.stable_begin();
1700 cleanupDominator = Builder.CreateUnreachable();
1701 }
1702
1703 assert((allocSize == allocSizeWithoutCookie) ==
1704 CalculateCookiePadding(*this, E).isZero());
1705 if (allocSize != allocSizeWithoutCookie) {
1706 assert(E->isArray());
1707 allocation = CGM.getCXXABI().InitializeArrayCookie(*this, allocation,
1708 numElements,
1709 E, allocType);
1710 }
1711
1712 llvm::Type *elementTy = ConvertTypeForMem(allocType);
1713 Address result = Builder.CreateElementBitCast(allocation, elementTy);
1714
1715 // Passing pointer through launder.invariant.group to avoid propagation of
1716 // vptrs information which may be included in previous type.
1717 // To not break LTO with different optimizations levels, we do it regardless
1718 // of optimization level.
1719 if (CGM.getCodeGenOpts().StrictVTablePointers &&
1720 allocator->isReservedGlobalPlacementOperator())
1721 result = Address(Builder.CreateLaunderInvariantGroup(result.getPointer()),
1722 result.getAlignment());
1723
1724 // Emit sanitizer checks for pointer value now, so that in the case of an
1725 // array it was checked only once and not at each constructor call. We may
1726 // have already checked that the pointer is non-null.
1727 // FIXME: If we have an array cookie and a potentially-throwing allocator,
1728 // we'll null check the wrong pointer here.
1729 SanitizerSet SkippedChecks;
1730 SkippedChecks.set(SanitizerKind::Null, nullCheck);
1731 EmitTypeCheck(CodeGenFunction::TCK_ConstructorCall,
1732 E->getAllocatedTypeSourceInfo()->getTypeLoc().getBeginLoc(),
1733 result.getPointer(), allocType, result.getAlignment(),
1734 SkippedChecks, numElements);
1735
1736 EmitNewInitializer(*this, E, allocType, elementTy, result, numElements,
1737 allocSizeWithoutCookie);
1738 if (E->isArray()) {
1739 // NewPtr is a pointer to the base element type. If we're
1740 // allocating an array of arrays, we'll need to cast back to the
1741 // array pointer type.
1742 llvm::Type *resultType = ConvertTypeForMem(E->getType());
1743 if (result.getType() != resultType)
1744 result = Builder.CreateBitCast(result, resultType);
1745 }
1746
1747 // Deactivate the 'operator delete' cleanup if we finished
1748 // initialization.
1749 if (operatorDeleteCleanup.isValid()) {
1750 DeactivateCleanupBlock(operatorDeleteCleanup, cleanupDominator);
1751 cleanupDominator->eraseFromParent();
1752 }
1753
1754 llvm::Value *resultPtr = result.getPointer();
1755 if (nullCheck) {
1756 conditional.end(*this);
1757
1758 llvm::BasicBlock *notNullBB = Builder.GetInsertBlock();
1759 EmitBlock(contBB);
1760
1761 llvm::PHINode *PHI = Builder.CreatePHI(resultPtr->getType(), 2);
1762 PHI->addIncoming(resultPtr, notNullBB);
1763 PHI->addIncoming(llvm::Constant::getNullValue(resultPtr->getType()),
1764 nullCheckBB);
1765
1766 resultPtr = PHI;
1767 }
1768
1769 return resultPtr;
1770 }
1771
EmitDeleteCall(const FunctionDecl * DeleteFD,llvm::Value * Ptr,QualType DeleteTy,llvm::Value * NumElements,CharUnits CookieSize)1772 void CodeGenFunction::EmitDeleteCall(const FunctionDecl *DeleteFD,
1773 llvm::Value *Ptr, QualType DeleteTy,
1774 llvm::Value *NumElements,
1775 CharUnits CookieSize) {
1776 assert((!NumElements && CookieSize.isZero()) ||
1777 DeleteFD->getOverloadedOperator() == OO_Array_Delete);
1778
1779 const auto *DeleteFTy = DeleteFD->getType()->castAs<FunctionProtoType>();
1780 CallArgList DeleteArgs;
1781
1782 auto Params = getUsualDeleteParams(DeleteFD);
1783 auto ParamTypeIt = DeleteFTy->param_type_begin();
1784
1785 // Pass the pointer itself.
1786 QualType ArgTy = *ParamTypeIt++;
1787 llvm::Value *DeletePtr = Builder.CreateBitCast(Ptr, ConvertType(ArgTy));
1788 DeleteArgs.add(RValue::get(DeletePtr), ArgTy);
1789
1790 // Pass the std::destroying_delete tag if present.
1791 llvm::AllocaInst *DestroyingDeleteTag = nullptr;
1792 if (Params.DestroyingDelete) {
1793 QualType DDTag = *ParamTypeIt++;
1794 llvm::Type *Ty = getTypes().ConvertType(DDTag);
1795 CharUnits Align = CGM.getNaturalTypeAlignment(DDTag);
1796 DestroyingDeleteTag = CreateTempAlloca(Ty, "destroying.delete.tag");
1797 DestroyingDeleteTag->setAlignment(Align.getAsAlign());
1798 DeleteArgs.add(RValue::getAggregate(Address(DestroyingDeleteTag, Align)), DDTag);
1799 }
1800
1801 // Pass the size if the delete function has a size_t parameter.
1802 if (Params.Size) {
1803 QualType SizeType = *ParamTypeIt++;
1804 CharUnits DeleteTypeSize = getContext().getTypeSizeInChars(DeleteTy);
1805 llvm::Value *Size = llvm::ConstantInt::get(ConvertType(SizeType),
1806 DeleteTypeSize.getQuantity());
1807
1808 // For array new, multiply by the number of elements.
1809 if (NumElements)
1810 Size = Builder.CreateMul(Size, NumElements);
1811
1812 // If there is a cookie, add the cookie size.
1813 if (!CookieSize.isZero())
1814 Size = Builder.CreateAdd(
1815 Size, llvm::ConstantInt::get(SizeTy, CookieSize.getQuantity()));
1816
1817 DeleteArgs.add(RValue::get(Size), SizeType);
1818 }
1819
1820 // Pass the alignment if the delete function has an align_val_t parameter.
1821 if (Params.Alignment) {
1822 QualType AlignValType = *ParamTypeIt++;
1823 CharUnits DeleteTypeAlign =
1824 getContext().toCharUnitsFromBits(getContext().getTypeAlignIfKnown(
1825 DeleteTy, true /* NeedsPreferredAlignment */));
1826 llvm::Value *Align = llvm::ConstantInt::get(ConvertType(AlignValType),
1827 DeleteTypeAlign.getQuantity());
1828 DeleteArgs.add(RValue::get(Align), AlignValType);
1829 }
1830
1831 assert(ParamTypeIt == DeleteFTy->param_type_end() &&
1832 "unknown parameter to usual delete function");
1833
1834 // Emit the call to delete.
1835 EmitNewDeleteCall(*this, DeleteFD, DeleteFTy, DeleteArgs);
1836
1837 // If call argument lowering didn't use the destroying_delete_t alloca,
1838 // remove it again.
1839 if (DestroyingDeleteTag && DestroyingDeleteTag->use_empty())
1840 DestroyingDeleteTag->eraseFromParent();
1841 }
1842
1843 namespace {
1844 /// Calls the given 'operator delete' on a single object.
1845 struct CallObjectDelete final : EHScopeStack::Cleanup {
1846 llvm::Value *Ptr;
1847 const FunctionDecl *OperatorDelete;
1848 QualType ElementType;
1849
CallObjectDelete__anon3639d9720511::CallObjectDelete1850 CallObjectDelete(llvm::Value *Ptr,
1851 const FunctionDecl *OperatorDelete,
1852 QualType ElementType)
1853 : Ptr(Ptr), OperatorDelete(OperatorDelete), ElementType(ElementType) {}
1854
Emit__anon3639d9720511::CallObjectDelete1855 void Emit(CodeGenFunction &CGF, Flags flags) override {
1856 CGF.EmitDeleteCall(OperatorDelete, Ptr, ElementType);
1857 }
1858 };
1859 }
1860
1861 void
pushCallObjectDeleteCleanup(const FunctionDecl * OperatorDelete,llvm::Value * CompletePtr,QualType ElementType)1862 CodeGenFunction::pushCallObjectDeleteCleanup(const FunctionDecl *OperatorDelete,
1863 llvm::Value *CompletePtr,
1864 QualType ElementType) {
1865 EHStack.pushCleanup<CallObjectDelete>(NormalAndEHCleanup, CompletePtr,
1866 OperatorDelete, ElementType);
1867 }
1868
1869 /// Emit the code for deleting a single object with a destroying operator
1870 /// delete. If the element type has a non-virtual destructor, Ptr has already
1871 /// been converted to the type of the parameter of 'operator delete'. Otherwise
1872 /// Ptr points to an object of the static type.
EmitDestroyingObjectDelete(CodeGenFunction & CGF,const CXXDeleteExpr * DE,Address Ptr,QualType ElementType)1873 static void EmitDestroyingObjectDelete(CodeGenFunction &CGF,
1874 const CXXDeleteExpr *DE, Address Ptr,
1875 QualType ElementType) {
1876 auto *Dtor = ElementType->getAsCXXRecordDecl()->getDestructor();
1877 if (Dtor && Dtor->isVirtual())
1878 CGF.CGM.getCXXABI().emitVirtualObjectDelete(CGF, DE, Ptr, ElementType,
1879 Dtor);
1880 else
1881 CGF.EmitDeleteCall(DE->getOperatorDelete(), Ptr.getPointer(), ElementType);
1882 }
1883
1884 /// Emit the code for deleting a single object.
1885 /// \return \c true if we started emitting UnconditionalDeleteBlock, \c false
1886 /// if not.
EmitObjectDelete(CodeGenFunction & CGF,const CXXDeleteExpr * DE,Address Ptr,QualType ElementType,llvm::BasicBlock * UnconditionalDeleteBlock)1887 static bool EmitObjectDelete(CodeGenFunction &CGF,
1888 const CXXDeleteExpr *DE,
1889 Address Ptr,
1890 QualType ElementType,
1891 llvm::BasicBlock *UnconditionalDeleteBlock) {
1892 // C++11 [expr.delete]p3:
1893 // If the static type of the object to be deleted is different from its
1894 // dynamic type, the static type shall be a base class of the dynamic type
1895 // of the object to be deleted and the static type shall have a virtual
1896 // destructor or the behavior is undefined.
1897 CGF.EmitTypeCheck(CodeGenFunction::TCK_MemberCall,
1898 DE->getExprLoc(), Ptr.getPointer(),
1899 ElementType);
1900
1901 const FunctionDecl *OperatorDelete = DE->getOperatorDelete();
1902 assert(!OperatorDelete->isDestroyingOperatorDelete());
1903
1904 // Find the destructor for the type, if applicable. If the
1905 // destructor is virtual, we'll just emit the vcall and return.
1906 const CXXDestructorDecl *Dtor = nullptr;
1907 if (const RecordType *RT = ElementType->getAs<RecordType>()) {
1908 CXXRecordDecl *RD = cast<CXXRecordDecl>(RT->getDecl());
1909 if (RD->hasDefinition() && !RD->hasTrivialDestructor()) {
1910 Dtor = RD->getDestructor();
1911
1912 if (Dtor->isVirtual()) {
1913 bool UseVirtualCall = true;
1914 const Expr *Base = DE->getArgument();
1915 if (auto *DevirtualizedDtor =
1916 dyn_cast_or_null<const CXXDestructorDecl>(
1917 Dtor->getDevirtualizedMethod(
1918 Base, CGF.CGM.getLangOpts().AppleKext))) {
1919 UseVirtualCall = false;
1920 const CXXRecordDecl *DevirtualizedClass =
1921 DevirtualizedDtor->getParent();
1922 if (declaresSameEntity(getCXXRecord(Base), DevirtualizedClass)) {
1923 // Devirtualized to the class of the base type (the type of the
1924 // whole expression).
1925 Dtor = DevirtualizedDtor;
1926 } else {
1927 // Devirtualized to some other type. Would need to cast the this
1928 // pointer to that type but we don't have support for that yet, so
1929 // do a virtual call. FIXME: handle the case where it is
1930 // devirtualized to the derived type (the type of the inner
1931 // expression) as in EmitCXXMemberOrOperatorMemberCallExpr.
1932 UseVirtualCall = true;
1933 }
1934 }
1935 if (UseVirtualCall) {
1936 CGF.CGM.getCXXABI().emitVirtualObjectDelete(CGF, DE, Ptr, ElementType,
1937 Dtor);
1938 return false;
1939 }
1940 }
1941 }
1942 }
1943
1944 // Make sure that we call delete even if the dtor throws.
1945 // This doesn't have to a conditional cleanup because we're going
1946 // to pop it off in a second.
1947 CGF.EHStack.pushCleanup<CallObjectDelete>(NormalAndEHCleanup,
1948 Ptr.getPointer(),
1949 OperatorDelete, ElementType);
1950
1951 if (Dtor)
1952 CGF.EmitCXXDestructorCall(Dtor, Dtor_Complete,
1953 /*ForVirtualBase=*/false,
1954 /*Delegating=*/false,
1955 Ptr, ElementType);
1956 else if (auto Lifetime = ElementType.getObjCLifetime()) {
1957 switch (Lifetime) {
1958 case Qualifiers::OCL_None:
1959 case Qualifiers::OCL_ExplicitNone:
1960 case Qualifiers::OCL_Autoreleasing:
1961 break;
1962
1963 case Qualifiers::OCL_Strong:
1964 CGF.EmitARCDestroyStrong(Ptr, ARCPreciseLifetime);
1965 break;
1966
1967 case Qualifiers::OCL_Weak:
1968 CGF.EmitARCDestroyWeak(Ptr);
1969 break;
1970 }
1971 }
1972
1973 // When optimizing for size, call 'operator delete' unconditionally.
1974 if (CGF.CGM.getCodeGenOpts().OptimizeSize > 1) {
1975 CGF.EmitBlock(UnconditionalDeleteBlock);
1976 CGF.PopCleanupBlock();
1977 return true;
1978 }
1979
1980 CGF.PopCleanupBlock();
1981 return false;
1982 }
1983
1984 namespace {
1985 /// Calls the given 'operator delete' on an array of objects.
1986 struct CallArrayDelete final : EHScopeStack::Cleanup {
1987 llvm::Value *Ptr;
1988 const FunctionDecl *OperatorDelete;
1989 llvm::Value *NumElements;
1990 QualType ElementType;
1991 CharUnits CookieSize;
1992
CallArrayDelete__anon3639d9720611::CallArrayDelete1993 CallArrayDelete(llvm::Value *Ptr,
1994 const FunctionDecl *OperatorDelete,
1995 llvm::Value *NumElements,
1996 QualType ElementType,
1997 CharUnits CookieSize)
1998 : Ptr(Ptr), OperatorDelete(OperatorDelete), NumElements(NumElements),
1999 ElementType(ElementType), CookieSize(CookieSize) {}
2000
Emit__anon3639d9720611::CallArrayDelete2001 void Emit(CodeGenFunction &CGF, Flags flags) override {
2002 CGF.EmitDeleteCall(OperatorDelete, Ptr, ElementType, NumElements,
2003 CookieSize);
2004 }
2005 };
2006 }
2007
2008 /// Emit the code for deleting an array of objects.
EmitArrayDelete(CodeGenFunction & CGF,const CXXDeleteExpr * E,Address deletedPtr,QualType elementType)2009 static void EmitArrayDelete(CodeGenFunction &CGF,
2010 const CXXDeleteExpr *E,
2011 Address deletedPtr,
2012 QualType elementType) {
2013 llvm::Value *numElements = nullptr;
2014 llvm::Value *allocatedPtr = nullptr;
2015 CharUnits cookieSize;
2016 CGF.CGM.getCXXABI().ReadArrayCookie(CGF, deletedPtr, E, elementType,
2017 numElements, allocatedPtr, cookieSize);
2018
2019 assert(allocatedPtr && "ReadArrayCookie didn't set allocated pointer");
2020
2021 // Make sure that we call delete even if one of the dtors throws.
2022 const FunctionDecl *operatorDelete = E->getOperatorDelete();
2023 CGF.EHStack.pushCleanup<CallArrayDelete>(NormalAndEHCleanup,
2024 allocatedPtr, operatorDelete,
2025 numElements, elementType,
2026 cookieSize);
2027
2028 // Destroy the elements.
2029 if (QualType::DestructionKind dtorKind = elementType.isDestructedType()) {
2030 assert(numElements && "no element count for a type with a destructor!");
2031
2032 CharUnits elementSize = CGF.getContext().getTypeSizeInChars(elementType);
2033 CharUnits elementAlign =
2034 deletedPtr.getAlignment().alignmentOfArrayElement(elementSize);
2035
2036 llvm::Value *arrayBegin = deletedPtr.getPointer();
2037 llvm::Value *arrayEnd =
2038 CGF.Builder.CreateInBoundsGEP(arrayBegin, numElements, "delete.end");
2039
2040 // Note that it is legal to allocate a zero-length array, and we
2041 // can never fold the check away because the length should always
2042 // come from a cookie.
2043 CGF.emitArrayDestroy(arrayBegin, arrayEnd, elementType, elementAlign,
2044 CGF.getDestroyer(dtorKind),
2045 /*checkZeroLength*/ true,
2046 CGF.needsEHCleanup(dtorKind));
2047 }
2048
2049 // Pop the cleanup block.
2050 CGF.PopCleanupBlock();
2051 }
2052
EmitCXXDeleteExpr(const CXXDeleteExpr * E)2053 void CodeGenFunction::EmitCXXDeleteExpr(const CXXDeleteExpr *E) {
2054 const Expr *Arg = E->getArgument();
2055 Address Ptr = EmitPointerWithAlignment(Arg);
2056
2057 // Null check the pointer.
2058 //
2059 // We could avoid this null check if we can determine that the object
2060 // destruction is trivial and doesn't require an array cookie; we can
2061 // unconditionally perform the operator delete call in that case. For now, we
2062 // assume that deleted pointers are null rarely enough that it's better to
2063 // keep the branch. This might be worth revisiting for a -O0 code size win.
2064 llvm::BasicBlock *DeleteNotNull = createBasicBlock("delete.notnull");
2065 llvm::BasicBlock *DeleteEnd = createBasicBlock("delete.end");
2066
2067 llvm::Value *IsNull = Builder.CreateIsNull(Ptr.getPointer(), "isnull");
2068
2069 Builder.CreateCondBr(IsNull, DeleteEnd, DeleteNotNull);
2070 EmitBlock(DeleteNotNull);
2071
2072 QualType DeleteTy = E->getDestroyedType();
2073
2074 // A destroying operator delete overrides the entire operation of the
2075 // delete expression.
2076 if (E->getOperatorDelete()->isDestroyingOperatorDelete()) {
2077 EmitDestroyingObjectDelete(*this, E, Ptr, DeleteTy);
2078 EmitBlock(DeleteEnd);
2079 return;
2080 }
2081
2082 // We might be deleting a pointer to array. If so, GEP down to the
2083 // first non-array element.
2084 // (this assumes that A(*)[3][7] is converted to [3 x [7 x %A]]*)
2085 if (DeleteTy->isConstantArrayType()) {
2086 llvm::Value *Zero = Builder.getInt32(0);
2087 SmallVector<llvm::Value*,8> GEP;
2088
2089 GEP.push_back(Zero); // point at the outermost array
2090
2091 // For each layer of array type we're pointing at:
2092 while (const ConstantArrayType *Arr
2093 = getContext().getAsConstantArrayType(DeleteTy)) {
2094 // 1. Unpeel the array type.
2095 DeleteTy = Arr->getElementType();
2096
2097 // 2. GEP to the first element of the array.
2098 GEP.push_back(Zero);
2099 }
2100
2101 Ptr = Address(Builder.CreateInBoundsGEP(Ptr.getPointer(), GEP, "del.first"),
2102 Ptr.getAlignment());
2103 }
2104
2105 assert(ConvertTypeForMem(DeleteTy) == Ptr.getElementType());
2106
2107 if (E->isArrayForm()) {
2108 EmitArrayDelete(*this, E, Ptr, DeleteTy);
2109 EmitBlock(DeleteEnd);
2110 } else {
2111 if (!EmitObjectDelete(*this, E, Ptr, DeleteTy, DeleteEnd))
2112 EmitBlock(DeleteEnd);
2113 }
2114 }
2115
isGLValueFromPointerDeref(const Expr * E)2116 static bool isGLValueFromPointerDeref(const Expr *E) {
2117 E = E->IgnoreParens();
2118
2119 if (const auto *CE = dyn_cast<CastExpr>(E)) {
2120 if (!CE->getSubExpr()->isGLValue())
2121 return false;
2122 return isGLValueFromPointerDeref(CE->getSubExpr());
2123 }
2124
2125 if (const auto *OVE = dyn_cast<OpaqueValueExpr>(E))
2126 return isGLValueFromPointerDeref(OVE->getSourceExpr());
2127
2128 if (const auto *BO = dyn_cast<BinaryOperator>(E))
2129 if (BO->getOpcode() == BO_Comma)
2130 return isGLValueFromPointerDeref(BO->getRHS());
2131
2132 if (const auto *ACO = dyn_cast<AbstractConditionalOperator>(E))
2133 return isGLValueFromPointerDeref(ACO->getTrueExpr()) ||
2134 isGLValueFromPointerDeref(ACO->getFalseExpr());
2135
2136 // C++11 [expr.sub]p1:
2137 // The expression E1[E2] is identical (by definition) to *((E1)+(E2))
2138 if (isa<ArraySubscriptExpr>(E))
2139 return true;
2140
2141 if (const auto *UO = dyn_cast<UnaryOperator>(E))
2142 if (UO->getOpcode() == UO_Deref)
2143 return true;
2144
2145 return false;
2146 }
2147
EmitTypeidFromVTable(CodeGenFunction & CGF,const Expr * E,llvm::Type * StdTypeInfoPtrTy)2148 static llvm::Value *EmitTypeidFromVTable(CodeGenFunction &CGF, const Expr *E,
2149 llvm::Type *StdTypeInfoPtrTy) {
2150 // Get the vtable pointer.
2151 Address ThisPtr = CGF.EmitLValue(E).getAddress(CGF);
2152
2153 QualType SrcRecordTy = E->getType();
2154
2155 // C++ [class.cdtor]p4:
2156 // If the operand of typeid refers to the object under construction or
2157 // destruction and the static type of the operand is neither the constructor
2158 // or destructor’s class nor one of its bases, the behavior is undefined.
2159 CGF.EmitTypeCheck(CodeGenFunction::TCK_DynamicOperation, E->getExprLoc(),
2160 ThisPtr.getPointer(), SrcRecordTy);
2161
2162 // C++ [expr.typeid]p2:
2163 // If the glvalue expression is obtained by applying the unary * operator to
2164 // a pointer and the pointer is a null pointer value, the typeid expression
2165 // throws the std::bad_typeid exception.
2166 //
2167 // However, this paragraph's intent is not clear. We choose a very generous
2168 // interpretation which implores us to consider comma operators, conditional
2169 // operators, parentheses and other such constructs.
2170 if (CGF.CGM.getCXXABI().shouldTypeidBeNullChecked(
2171 isGLValueFromPointerDeref(E), SrcRecordTy)) {
2172 llvm::BasicBlock *BadTypeidBlock =
2173 CGF.createBasicBlock("typeid.bad_typeid");
2174 llvm::BasicBlock *EndBlock = CGF.createBasicBlock("typeid.end");
2175
2176 llvm::Value *IsNull = CGF.Builder.CreateIsNull(ThisPtr.getPointer());
2177 CGF.Builder.CreateCondBr(IsNull, BadTypeidBlock, EndBlock);
2178
2179 CGF.EmitBlock(BadTypeidBlock);
2180 CGF.CGM.getCXXABI().EmitBadTypeidCall(CGF);
2181 CGF.EmitBlock(EndBlock);
2182 }
2183
2184 return CGF.CGM.getCXXABI().EmitTypeid(CGF, SrcRecordTy, ThisPtr,
2185 StdTypeInfoPtrTy);
2186 }
2187
EmitCXXTypeidExpr(const CXXTypeidExpr * E)2188 llvm::Value *CodeGenFunction::EmitCXXTypeidExpr(const CXXTypeidExpr *E) {
2189 llvm::Type *StdTypeInfoPtrTy =
2190 ConvertType(E->getType())->getPointerTo();
2191
2192 if (E->isTypeOperand()) {
2193 llvm::Constant *TypeInfo =
2194 CGM.GetAddrOfRTTIDescriptor(E->getTypeOperand(getContext()));
2195 return Builder.CreateBitCast(TypeInfo, StdTypeInfoPtrTy);
2196 }
2197
2198 // C++ [expr.typeid]p2:
2199 // When typeid is applied to a glvalue expression whose type is a
2200 // polymorphic class type, the result refers to a std::type_info object
2201 // representing the type of the most derived object (that is, the dynamic
2202 // type) to which the glvalue refers.
2203 // If the operand is already most derived object, no need to look up vtable.
2204 if (E->isPotentiallyEvaluated() && !E->isMostDerived(getContext()))
2205 return EmitTypeidFromVTable(*this, E->getExprOperand(),
2206 StdTypeInfoPtrTy);
2207
2208 QualType OperandTy = E->getExprOperand()->getType();
2209 return Builder.CreateBitCast(CGM.GetAddrOfRTTIDescriptor(OperandTy),
2210 StdTypeInfoPtrTy);
2211 }
2212
EmitDynamicCastToNull(CodeGenFunction & CGF,QualType DestTy)2213 static llvm::Value *EmitDynamicCastToNull(CodeGenFunction &CGF,
2214 QualType DestTy) {
2215 llvm::Type *DestLTy = CGF.ConvertType(DestTy);
2216 if (DestTy->isPointerType())
2217 return llvm::Constant::getNullValue(DestLTy);
2218
2219 /// C++ [expr.dynamic.cast]p9:
2220 /// A failed cast to reference type throws std::bad_cast
2221 if (!CGF.CGM.getCXXABI().EmitBadCastCall(CGF))
2222 return nullptr;
2223
2224 CGF.EmitBlock(CGF.createBasicBlock("dynamic_cast.end"));
2225 return llvm::UndefValue::get(DestLTy);
2226 }
2227
EmitDynamicCast(Address ThisAddr,const CXXDynamicCastExpr * DCE)2228 llvm::Value *CodeGenFunction::EmitDynamicCast(Address ThisAddr,
2229 const CXXDynamicCastExpr *DCE) {
2230 CGM.EmitExplicitCastExprType(DCE, this);
2231 QualType DestTy = DCE->getTypeAsWritten();
2232
2233 QualType SrcTy = DCE->getSubExpr()->getType();
2234
2235 // C++ [expr.dynamic.cast]p7:
2236 // If T is "pointer to cv void," then the result is a pointer to the most
2237 // derived object pointed to by v.
2238 const PointerType *DestPTy = DestTy->getAs<PointerType>();
2239
2240 bool isDynamicCastToVoid;
2241 QualType SrcRecordTy;
2242 QualType DestRecordTy;
2243 if (DestPTy) {
2244 isDynamicCastToVoid = DestPTy->getPointeeType()->isVoidType();
2245 SrcRecordTy = SrcTy->castAs<PointerType>()->getPointeeType();
2246 DestRecordTy = DestPTy->getPointeeType();
2247 } else {
2248 isDynamicCastToVoid = false;
2249 SrcRecordTy = SrcTy;
2250 DestRecordTy = DestTy->castAs<ReferenceType>()->getPointeeType();
2251 }
2252
2253 // C++ [class.cdtor]p5:
2254 // If the operand of the dynamic_cast refers to the object under
2255 // construction or destruction and the static type of the operand is not a
2256 // pointer to or object of the constructor or destructor’s own class or one
2257 // of its bases, the dynamic_cast results in undefined behavior.
2258 EmitTypeCheck(TCK_DynamicOperation, DCE->getExprLoc(), ThisAddr.getPointer(),
2259 SrcRecordTy);
2260
2261 if (DCE->isAlwaysNull())
2262 if (llvm::Value *T = EmitDynamicCastToNull(*this, DestTy))
2263 return T;
2264
2265 assert(SrcRecordTy->isRecordType() && "source type must be a record type!");
2266
2267 // C++ [expr.dynamic.cast]p4:
2268 // If the value of v is a null pointer value in the pointer case, the result
2269 // is the null pointer value of type T.
2270 bool ShouldNullCheckSrcValue =
2271 CGM.getCXXABI().shouldDynamicCastCallBeNullChecked(SrcTy->isPointerType(),
2272 SrcRecordTy);
2273
2274 llvm::BasicBlock *CastNull = nullptr;
2275 llvm::BasicBlock *CastNotNull = nullptr;
2276 llvm::BasicBlock *CastEnd = createBasicBlock("dynamic_cast.end");
2277
2278 if (ShouldNullCheckSrcValue) {
2279 CastNull = createBasicBlock("dynamic_cast.null");
2280 CastNotNull = createBasicBlock("dynamic_cast.notnull");
2281
2282 llvm::Value *IsNull = Builder.CreateIsNull(ThisAddr.getPointer());
2283 Builder.CreateCondBr(IsNull, CastNull, CastNotNull);
2284 EmitBlock(CastNotNull);
2285 }
2286
2287 llvm::Value *Value;
2288 if (isDynamicCastToVoid) {
2289 Value = CGM.getCXXABI().EmitDynamicCastToVoid(*this, ThisAddr, SrcRecordTy,
2290 DestTy);
2291 } else {
2292 assert(DestRecordTy->isRecordType() &&
2293 "destination type must be a record type!");
2294 Value = CGM.getCXXABI().EmitDynamicCastCall(*this, ThisAddr, SrcRecordTy,
2295 DestTy, DestRecordTy, CastEnd);
2296 CastNotNull = Builder.GetInsertBlock();
2297 }
2298
2299 if (ShouldNullCheckSrcValue) {
2300 EmitBranch(CastEnd);
2301
2302 EmitBlock(CastNull);
2303 EmitBranch(CastEnd);
2304 }
2305
2306 EmitBlock(CastEnd);
2307
2308 if (ShouldNullCheckSrcValue) {
2309 llvm::PHINode *PHI = Builder.CreatePHI(Value->getType(), 2);
2310 PHI->addIncoming(Value, CastNotNull);
2311 PHI->addIncoming(llvm::Constant::getNullValue(Value->getType()), CastNull);
2312
2313 Value = PHI;
2314 }
2315
2316 return Value;
2317 }
2318