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,GlobalDecl GD,llvm::Value * This,llvm::Value * ImplicitParam,QualType ImplicitParamTy,const CallExpr * CE,CallArgList & Args,CallArgList * RtlArgs)36 commonEmitCXXMemberOrOperatorCall(CodeGenFunction &CGF, GlobalDecl GD,
37 llvm::Value *This, llvm::Value *ImplicitParam,
38 QualType ImplicitParamTy, const CallExpr *CE,
39 CallArgList &Args, CallArgList *RtlArgs) {
40 auto *MD = cast<CXXMethodDecl>(GD.getDecl());
41
42 assert(CE == nullptr || isa<CXXMemberCallExpr>(CE) ||
43 isa<CXXOperatorCallExpr>(CE));
44 assert(MD->isImplicitObjectMemberFunction() &&
45 "Trying to emit a member or operator call expr on a static method!");
46
47 // Push the this ptr.
48 const CXXRecordDecl *RD =
49 CGF.CGM.getCXXABI().getThisArgumentTypeForMethod(GD);
50 Args.add(RValue::get(This), CGF.getTypes().DeriveThisType(RD, MD));
51
52 // If there is an implicit parameter (e.g. VTT), emit it.
53 if (ImplicitParam) {
54 Args.add(RValue::get(ImplicitParam), ImplicitParamTy);
55 }
56
57 const FunctionProtoType *FPT = MD->getType()->castAs<FunctionProtoType>();
58 RequiredArgs required = RequiredArgs::forPrototypePlus(FPT, Args.size());
59 unsigned PrefixSize = Args.size() - 1;
60
61 // And the rest of the call args.
62 if (RtlArgs) {
63 // Special case: if the caller emitted the arguments right-to-left already
64 // (prior to emitting the *this argument), we're done. This happens for
65 // assignment operators.
66 Args.addFrom(*RtlArgs);
67 } else if (CE) {
68 // Special case: skip first argument of CXXOperatorCall (it is "this").
69 unsigned ArgsToSkip = 0;
70 if (const auto *Op = dyn_cast<CXXOperatorCallExpr>(CE)) {
71 if (const auto *M = dyn_cast<CXXMethodDecl>(Op->getCalleeDecl()))
72 ArgsToSkip =
73 static_cast<unsigned>(!M->isExplicitObjectMemberFunction());
74 }
75 CGF.EmitCallArgs(Args, FPT, drop_begin(CE->arguments(), ArgsToSkip),
76 CE->getDirectCallee());
77 } else {
78 assert(
79 FPT->getNumParams() == 0 &&
80 "No CallExpr specified for function with non-zero number of arguments");
81 }
82 return {required, PrefixSize};
83 }
84
EmitCXXMemberOrOperatorCall(const CXXMethodDecl * MD,const CGCallee & Callee,ReturnValueSlot ReturnValue,llvm::Value * This,llvm::Value * ImplicitParam,QualType ImplicitParamTy,const CallExpr * CE,CallArgList * RtlArgs)85 RValue CodeGenFunction::EmitCXXMemberOrOperatorCall(
86 const CXXMethodDecl *MD, const CGCallee &Callee,
87 ReturnValueSlot ReturnValue,
88 llvm::Value *This, llvm::Value *ImplicitParam, QualType ImplicitParamTy,
89 const CallExpr *CE, CallArgList *RtlArgs) {
90 const FunctionProtoType *FPT = MD->getType()->castAs<FunctionProtoType>();
91 CallArgList Args;
92 MemberCallInfo CallInfo = commonEmitCXXMemberOrOperatorCall(
93 *this, MD, This, ImplicitParam, ImplicitParamTy, CE, Args, RtlArgs);
94 auto &FnInfo = CGM.getTypes().arrangeCXXMethodCall(
95 Args, FPT, CallInfo.ReqArgs, CallInfo.PrefixSize);
96 return EmitCall(FnInfo, Callee, ReturnValue, Args, nullptr,
97 CE && CE == MustTailCall,
98 CE ? CE->getExprLoc() : SourceLocation());
99 }
100
EmitCXXDestructorCall(GlobalDecl Dtor,const CGCallee & Callee,llvm::Value * This,QualType ThisTy,llvm::Value * ImplicitParam,QualType ImplicitParamTy,const CallExpr * CE)101 RValue CodeGenFunction::EmitCXXDestructorCall(
102 GlobalDecl Dtor, const CGCallee &Callee, llvm::Value *This, QualType ThisTy,
103 llvm::Value *ImplicitParam, QualType ImplicitParamTy, const CallExpr *CE) {
104 const CXXMethodDecl *DtorDecl = cast<CXXMethodDecl>(Dtor.getDecl());
105
106 assert(!ThisTy.isNull());
107 assert(ThisTy->getAsCXXRecordDecl() == DtorDecl->getParent() &&
108 "Pointer/Object mixup");
109
110 LangAS SrcAS = ThisTy.getAddressSpace();
111 LangAS DstAS = DtorDecl->getMethodQualifiers().getAddressSpace();
112 if (SrcAS != DstAS) {
113 QualType DstTy = DtorDecl->getThisType();
114 llvm::Type *NewType = CGM.getTypes().ConvertType(DstTy);
115 This = getTargetHooks().performAddrSpaceCast(*this, This, SrcAS, DstAS,
116 NewType);
117 }
118
119 CallArgList Args;
120 commonEmitCXXMemberOrOperatorCall(*this, Dtor, This, ImplicitParam,
121 ImplicitParamTy, CE, Args, nullptr);
122 return EmitCall(CGM.getTypes().arrangeCXXStructorDeclaration(Dtor), Callee,
123 ReturnValueSlot(), Args, nullptr, CE && CE == MustTailCall,
124 CE ? CE->getExprLoc() : SourceLocation{});
125 }
126
EmitCXXPseudoDestructorExpr(const CXXPseudoDestructorExpr * E)127 RValue CodeGenFunction::EmitCXXPseudoDestructorExpr(
128 const CXXPseudoDestructorExpr *E) {
129 QualType DestroyedType = E->getDestroyedType();
130 if (DestroyedType.hasStrongOrWeakObjCLifetime()) {
131 // Automatic Reference Counting:
132 // If the pseudo-expression names a retainable object with weak or
133 // strong lifetime, the object shall be released.
134 Expr *BaseExpr = E->getBase();
135 Address BaseValue = Address::invalid();
136 Qualifiers BaseQuals;
137
138 // If this is s.x, emit s as an lvalue. If it is s->x, emit s as a scalar.
139 if (E->isArrow()) {
140 BaseValue = EmitPointerWithAlignment(BaseExpr);
141 const auto *PTy = BaseExpr->getType()->castAs<PointerType>();
142 BaseQuals = PTy->getPointeeType().getQualifiers();
143 } else {
144 LValue BaseLV = EmitLValue(BaseExpr);
145 BaseValue = BaseLV.getAddress(*this);
146 QualType BaseTy = BaseExpr->getType();
147 BaseQuals = BaseTy.getQualifiers();
148 }
149
150 switch (DestroyedType.getObjCLifetime()) {
151 case Qualifiers::OCL_None:
152 case Qualifiers::OCL_ExplicitNone:
153 case Qualifiers::OCL_Autoreleasing:
154 break;
155
156 case Qualifiers::OCL_Strong:
157 EmitARCRelease(Builder.CreateLoad(BaseValue,
158 DestroyedType.isVolatileQualified()),
159 ARCPreciseLifetime);
160 break;
161
162 case Qualifiers::OCL_Weak:
163 EmitARCDestroyWeak(BaseValue);
164 break;
165 }
166 } else {
167 // C++ [expr.pseudo]p1:
168 // The result shall only be used as the operand for the function call
169 // operator (), and the result of such a call has type void. The only
170 // effect is the evaluation of the postfix-expression before the dot or
171 // arrow.
172 EmitIgnoredExpr(E->getBase());
173 }
174
175 return RValue::get(nullptr);
176 }
177
getCXXRecord(const Expr * E)178 static CXXRecordDecl *getCXXRecord(const Expr *E) {
179 QualType T = E->getType();
180 if (const PointerType *PTy = T->getAs<PointerType>())
181 T = PTy->getPointeeType();
182 const RecordType *Ty = T->castAs<RecordType>();
183 return cast<CXXRecordDecl>(Ty->getDecl());
184 }
185
186 // Note: This function also emit constructor calls to support a MSVC
187 // extensions allowing explicit constructor function call.
EmitCXXMemberCallExpr(const CXXMemberCallExpr * CE,ReturnValueSlot ReturnValue)188 RValue CodeGenFunction::EmitCXXMemberCallExpr(const CXXMemberCallExpr *CE,
189 ReturnValueSlot ReturnValue) {
190 const Expr *callee = CE->getCallee()->IgnoreParens();
191
192 if (isa<BinaryOperator>(callee))
193 return EmitCXXMemberPointerCallExpr(CE, ReturnValue);
194
195 const MemberExpr *ME = cast<MemberExpr>(callee);
196 const CXXMethodDecl *MD = cast<CXXMethodDecl>(ME->getMemberDecl());
197
198 if (MD->isStatic()) {
199 // The method is static, emit it as we would a regular call.
200 CGCallee callee =
201 CGCallee::forDirect(CGM.GetAddrOfFunction(MD), GlobalDecl(MD));
202 return EmitCall(getContext().getPointerType(MD->getType()), callee, CE,
203 ReturnValue);
204 }
205
206 bool HasQualifier = ME->hasQualifier();
207 NestedNameSpecifier *Qualifier = HasQualifier ? ME->getQualifier() : nullptr;
208 bool IsArrow = ME->isArrow();
209 const Expr *Base = ME->getBase();
210
211 return EmitCXXMemberOrOperatorMemberCallExpr(
212 CE, MD, ReturnValue, HasQualifier, Qualifier, IsArrow, Base);
213 }
214
EmitCXXMemberOrOperatorMemberCallExpr(const CallExpr * CE,const CXXMethodDecl * MD,ReturnValueSlot ReturnValue,bool HasQualifier,NestedNameSpecifier * Qualifier,bool IsArrow,const Expr * Base)215 RValue CodeGenFunction::EmitCXXMemberOrOperatorMemberCallExpr(
216 const CallExpr *CE, const CXXMethodDecl *MD, ReturnValueSlot ReturnValue,
217 bool HasQualifier, NestedNameSpecifier *Qualifier, bool IsArrow,
218 const Expr *Base) {
219 assert(isa<CXXMemberCallExpr>(CE) || isa<CXXOperatorCallExpr>(CE));
220
221 // Compute the object pointer.
222 bool CanUseVirtualCall = MD->isVirtual() && !HasQualifier;
223
224 const CXXMethodDecl *DevirtualizedMethod = nullptr;
225 if (CanUseVirtualCall &&
226 MD->getDevirtualizedMethod(Base, getLangOpts().AppleKext)) {
227 const CXXRecordDecl *BestDynamicDecl = Base->getBestDynamicClassType();
228 DevirtualizedMethod = MD->getCorrespondingMethodInClass(BestDynamicDecl);
229 assert(DevirtualizedMethod);
230 const CXXRecordDecl *DevirtualizedClass = DevirtualizedMethod->getParent();
231 const Expr *Inner = Base->IgnoreParenBaseCasts();
232 if (DevirtualizedMethod->getReturnType().getCanonicalType() !=
233 MD->getReturnType().getCanonicalType())
234 // If the return types are not the same, this might be a case where more
235 // code needs to run to compensate for it. For example, the derived
236 // method might return a type that inherits form from the return
237 // type of MD and has a prefix.
238 // For now we just avoid devirtualizing these covariant cases.
239 DevirtualizedMethod = nullptr;
240 else if (getCXXRecord(Inner) == DevirtualizedClass)
241 // If the class of the Inner expression is where the dynamic method
242 // is defined, build the this pointer from it.
243 Base = Inner;
244 else if (getCXXRecord(Base) != DevirtualizedClass) {
245 // If the method is defined in a class that is not the best dynamic
246 // one or the one of the full expression, we would have to build
247 // a derived-to-base cast to compute the correct this pointer, but
248 // we don't have support for that yet, so do a virtual call.
249 DevirtualizedMethod = nullptr;
250 }
251 }
252
253 bool TrivialForCodegen =
254 MD->isTrivial() || (MD->isDefaulted() && MD->getParent()->isUnion());
255 bool TrivialAssignment =
256 TrivialForCodegen &&
257 (MD->isCopyAssignmentOperator() || MD->isMoveAssignmentOperator()) &&
258 !MD->getParent()->mayInsertExtraPadding();
259
260 // C++17 demands that we evaluate the RHS of a (possibly-compound) assignment
261 // operator before the LHS.
262 CallArgList RtlArgStorage;
263 CallArgList *RtlArgs = nullptr;
264 LValue TrivialAssignmentRHS;
265 if (auto *OCE = dyn_cast<CXXOperatorCallExpr>(CE)) {
266 if (OCE->isAssignmentOp()) {
267 if (TrivialAssignment) {
268 TrivialAssignmentRHS = EmitLValue(CE->getArg(1));
269 } else {
270 RtlArgs = &RtlArgStorage;
271 EmitCallArgs(*RtlArgs, MD->getType()->castAs<FunctionProtoType>(),
272 drop_begin(CE->arguments(), 1), CE->getDirectCallee(),
273 /*ParamsToSkip*/0, EvaluationOrder::ForceRightToLeft);
274 }
275 }
276 }
277
278 LValue This;
279 if (IsArrow) {
280 LValueBaseInfo BaseInfo;
281 TBAAAccessInfo TBAAInfo;
282 Address ThisValue = EmitPointerWithAlignment(Base, &BaseInfo, &TBAAInfo);
283 This = MakeAddrLValue(ThisValue, Base->getType(), BaseInfo, TBAAInfo);
284 } else {
285 This = EmitLValue(Base);
286 }
287
288 if (const CXXConstructorDecl *Ctor = dyn_cast<CXXConstructorDecl>(MD)) {
289 // This is the MSVC p->Ctor::Ctor(...) extension. We assume that's
290 // constructing a new complete object of type Ctor.
291 assert(!RtlArgs);
292 assert(ReturnValue.isNull() && "Constructor shouldn't have return value");
293 CallArgList Args;
294 commonEmitCXXMemberOrOperatorCall(
295 *this, {Ctor, Ctor_Complete}, This.getPointer(*this),
296 /*ImplicitParam=*/nullptr,
297 /*ImplicitParamTy=*/QualType(), CE, Args, nullptr);
298
299 EmitCXXConstructorCall(Ctor, Ctor_Complete, /*ForVirtualBase=*/false,
300 /*Delegating=*/false, This.getAddress(*this), Args,
301 AggValueSlot::DoesNotOverlap, CE->getExprLoc(),
302 /*NewPointerIsChecked=*/false);
303 return RValue::get(nullptr);
304 }
305
306 if (TrivialForCodegen) {
307 if (isa<CXXDestructorDecl>(MD))
308 return RValue::get(nullptr);
309
310 if (TrivialAssignment) {
311 // We don't like to generate the trivial copy/move assignment operator
312 // when it isn't necessary; just produce the proper effect here.
313 // It's important that we use the result of EmitLValue here rather than
314 // emitting call arguments, in order to preserve TBAA information from
315 // the RHS.
316 LValue RHS = isa<CXXOperatorCallExpr>(CE)
317 ? TrivialAssignmentRHS
318 : EmitLValue(*CE->arg_begin());
319 EmitAggregateAssign(This, RHS, CE->getType());
320 return RValue::get(This.getPointer(*this));
321 }
322
323 assert(MD->getParent()->mayInsertExtraPadding() &&
324 "unknown trivial member function");
325 }
326
327 // Compute the function type we're calling.
328 const CXXMethodDecl *CalleeDecl =
329 DevirtualizedMethod ? DevirtualizedMethod : MD;
330 const CGFunctionInfo *FInfo = nullptr;
331 if (const auto *Dtor = dyn_cast<CXXDestructorDecl>(CalleeDecl))
332 FInfo = &CGM.getTypes().arrangeCXXStructorDeclaration(
333 GlobalDecl(Dtor, Dtor_Complete));
334 else
335 FInfo = &CGM.getTypes().arrangeCXXMethodDeclaration(CalleeDecl);
336
337 llvm::FunctionType *Ty = CGM.getTypes().GetFunctionType(*FInfo);
338
339 // C++11 [class.mfct.non-static]p2:
340 // If a non-static member function of a class X is called for an object that
341 // is not of type X, or of a type derived from X, the behavior is undefined.
342 SourceLocation CallLoc;
343 ASTContext &C = getContext();
344 if (CE)
345 CallLoc = CE->getExprLoc();
346
347 SanitizerSet SkippedChecks;
348 if (const auto *CMCE = dyn_cast<CXXMemberCallExpr>(CE)) {
349 auto *IOA = CMCE->getImplicitObjectArgument();
350 bool IsImplicitObjectCXXThis = IsWrappedCXXThis(IOA);
351 if (IsImplicitObjectCXXThis)
352 SkippedChecks.set(SanitizerKind::Alignment, true);
353 if (IsImplicitObjectCXXThis || isa<DeclRefExpr>(IOA))
354 SkippedChecks.set(SanitizerKind::Null, true);
355 }
356 EmitTypeCheck(CodeGenFunction::TCK_MemberCall, CallLoc,
357 This.getPointer(*this),
358 C.getRecordType(CalleeDecl->getParent()),
359 /*Alignment=*/CharUnits::Zero(), SkippedChecks);
360
361 // C++ [class.virtual]p12:
362 // Explicit qualification with the scope operator (5.1) suppresses the
363 // virtual call mechanism.
364 //
365 // We also don't emit a virtual call if the base expression has a record type
366 // because then we know what the type is.
367 bool UseVirtualCall = CanUseVirtualCall && !DevirtualizedMethod;
368
369 if (const CXXDestructorDecl *Dtor = dyn_cast<CXXDestructorDecl>(CalleeDecl)) {
370 assert(CE->arg_begin() == CE->arg_end() &&
371 "Destructor shouldn't have explicit parameters");
372 assert(ReturnValue.isNull() && "Destructor shouldn't have return value");
373 if (UseVirtualCall) {
374 CGM.getCXXABI().EmitVirtualDestructorCall(*this, Dtor, Dtor_Complete,
375 This.getAddress(*this),
376 cast<CXXMemberCallExpr>(CE));
377 } else {
378 GlobalDecl GD(Dtor, Dtor_Complete);
379 CGCallee Callee;
380 if (getLangOpts().AppleKext && Dtor->isVirtual() && HasQualifier)
381 Callee = BuildAppleKextVirtualCall(Dtor, Qualifier, Ty);
382 else if (!DevirtualizedMethod)
383 Callee =
384 CGCallee::forDirect(CGM.getAddrOfCXXStructor(GD, FInfo, Ty), GD);
385 else {
386 Callee = CGCallee::forDirect(CGM.GetAddrOfFunction(GD, Ty), GD);
387 }
388
389 QualType ThisTy =
390 IsArrow ? Base->getType()->getPointeeType() : Base->getType();
391 EmitCXXDestructorCall(GD, Callee, This.getPointer(*this), ThisTy,
392 /*ImplicitParam=*/nullptr,
393 /*ImplicitParamTy=*/QualType(), CE);
394 }
395 return RValue::get(nullptr);
396 }
397
398 // FIXME: Uses of 'MD' past this point need to be audited. We may need to use
399 // 'CalleeDecl' instead.
400
401 CGCallee Callee;
402 if (UseVirtualCall) {
403 Callee = CGCallee::forVirtual(CE, MD, This.getAddress(*this), Ty);
404 } else {
405 if (SanOpts.has(SanitizerKind::CFINVCall) &&
406 MD->getParent()->isDynamicClass()) {
407 llvm::Value *VTable;
408 const CXXRecordDecl *RD;
409 std::tie(VTable, RD) = CGM.getCXXABI().LoadVTablePtr(
410 *this, This.getAddress(*this), CalleeDecl->getParent());
411 EmitVTablePtrCheckForCall(RD, VTable, CFITCK_NVCall, CE->getBeginLoc());
412 }
413
414 if (getLangOpts().AppleKext && MD->isVirtual() && HasQualifier)
415 Callee = BuildAppleKextVirtualCall(MD, Qualifier, Ty);
416 else if (!DevirtualizedMethod)
417 Callee =
418 CGCallee::forDirect(CGM.GetAddrOfFunction(MD, Ty), GlobalDecl(MD));
419 else {
420 Callee =
421 CGCallee::forDirect(CGM.GetAddrOfFunction(DevirtualizedMethod, Ty),
422 GlobalDecl(DevirtualizedMethod));
423 }
424 }
425
426 if (MD->isVirtual()) {
427 Address NewThisAddr =
428 CGM.getCXXABI().adjustThisArgumentForVirtualFunctionCall(
429 *this, CalleeDecl, This.getAddress(*this), UseVirtualCall);
430 This.setAddress(NewThisAddr);
431 }
432
433 return EmitCXXMemberOrOperatorCall(
434 CalleeDecl, Callee, ReturnValue, This.getPointer(*this),
435 /*ImplicitParam=*/nullptr, QualType(), CE, RtlArgs);
436 }
437
438 RValue
EmitCXXMemberPointerCallExpr(const CXXMemberCallExpr * E,ReturnValueSlot ReturnValue)439 CodeGenFunction::EmitCXXMemberPointerCallExpr(const CXXMemberCallExpr *E,
440 ReturnValueSlot ReturnValue) {
441 const BinaryOperator *BO =
442 cast<BinaryOperator>(E->getCallee()->IgnoreParens());
443 const Expr *BaseExpr = BO->getLHS();
444 const Expr *MemFnExpr = BO->getRHS();
445
446 const auto *MPT = MemFnExpr->getType()->castAs<MemberPointerType>();
447 const auto *FPT = MPT->getPointeeType()->castAs<FunctionProtoType>();
448 const auto *RD =
449 cast<CXXRecordDecl>(MPT->getClass()->castAs<RecordType>()->getDecl());
450
451 // Emit the 'this' pointer.
452 Address This = Address::invalid();
453 if (BO->getOpcode() == BO_PtrMemI)
454 This = EmitPointerWithAlignment(BaseExpr, nullptr, nullptr, KnownNonNull);
455 else
456 This = EmitLValue(BaseExpr, KnownNonNull).getAddress(*this);
457
458 EmitTypeCheck(TCK_MemberCall, E->getExprLoc(), This.getPointer(),
459 QualType(MPT->getClass(), 0));
460
461 // Get the member function pointer.
462 llvm::Value *MemFnPtr = EmitScalarExpr(MemFnExpr);
463
464 // Ask the ABI to load the callee. Note that This is modified.
465 llvm::Value *ThisPtrForCall = nullptr;
466 CGCallee Callee =
467 CGM.getCXXABI().EmitLoadOfMemberFunctionPointer(*this, BO, This,
468 ThisPtrForCall, MemFnPtr, MPT);
469
470 CallArgList Args;
471
472 QualType ThisType =
473 getContext().getPointerType(getContext().getTagDeclType(RD));
474
475 // Push the this ptr.
476 Args.add(RValue::get(ThisPtrForCall), ThisType);
477
478 RequiredArgs required = RequiredArgs::forPrototypePlus(FPT, 1);
479
480 // And the rest of the call args
481 EmitCallArgs(Args, FPT, E->arguments());
482 return EmitCall(CGM.getTypes().arrangeCXXMethodCall(Args, FPT, required,
483 /*PrefixSize=*/0),
484 Callee, ReturnValue, Args, nullptr, E == MustTailCall,
485 E->getExprLoc());
486 }
487
488 RValue
EmitCXXOperatorMemberCallExpr(const CXXOperatorCallExpr * E,const CXXMethodDecl * MD,ReturnValueSlot ReturnValue)489 CodeGenFunction::EmitCXXOperatorMemberCallExpr(const CXXOperatorCallExpr *E,
490 const CXXMethodDecl *MD,
491 ReturnValueSlot ReturnValue) {
492 assert(MD->isImplicitObjectMemberFunction() &&
493 "Trying to emit a member call expr on a static method!");
494 return EmitCXXMemberOrOperatorMemberCallExpr(
495 E, MD, ReturnValue, /*HasQualifier=*/false, /*Qualifier=*/nullptr,
496 /*IsArrow=*/false, E->getArg(0));
497 }
498
EmitCUDAKernelCallExpr(const CUDAKernelCallExpr * E,ReturnValueSlot ReturnValue)499 RValue CodeGenFunction::EmitCUDAKernelCallExpr(const CUDAKernelCallExpr *E,
500 ReturnValueSlot ReturnValue) {
501 return CGM.getCUDARuntime().EmitCUDAKernelCallExpr(*this, E, ReturnValue);
502 }
503
EmitNullBaseClassInitialization(CodeGenFunction & CGF,Address DestPtr,const CXXRecordDecl * Base)504 static void EmitNullBaseClassInitialization(CodeGenFunction &CGF,
505 Address DestPtr,
506 const CXXRecordDecl *Base) {
507 if (Base->isEmpty())
508 return;
509
510 DestPtr = DestPtr.withElementType(CGF.Int8Ty);
511
512 const ASTRecordLayout &Layout = CGF.getContext().getASTRecordLayout(Base);
513 CharUnits NVSize = Layout.getNonVirtualSize();
514
515 // We cannot simply zero-initialize the entire base sub-object if vbptrs are
516 // present, they are initialized by the most derived class before calling the
517 // constructor.
518 SmallVector<std::pair<CharUnits, CharUnits>, 1> Stores;
519 Stores.emplace_back(CharUnits::Zero(), NVSize);
520
521 // Each store is split by the existence of a vbptr.
522 CharUnits VBPtrWidth = CGF.getPointerSize();
523 std::vector<CharUnits> VBPtrOffsets =
524 CGF.CGM.getCXXABI().getVBPtrOffsets(Base);
525 for (CharUnits VBPtrOffset : VBPtrOffsets) {
526 // Stop before we hit any virtual base pointers located in virtual bases.
527 if (VBPtrOffset >= NVSize)
528 break;
529 std::pair<CharUnits, CharUnits> LastStore = Stores.pop_back_val();
530 CharUnits LastStoreOffset = LastStore.first;
531 CharUnits LastStoreSize = LastStore.second;
532
533 CharUnits SplitBeforeOffset = LastStoreOffset;
534 CharUnits SplitBeforeSize = VBPtrOffset - SplitBeforeOffset;
535 assert(!SplitBeforeSize.isNegative() && "negative store size!");
536 if (!SplitBeforeSize.isZero())
537 Stores.emplace_back(SplitBeforeOffset, SplitBeforeSize);
538
539 CharUnits SplitAfterOffset = VBPtrOffset + VBPtrWidth;
540 CharUnits SplitAfterSize = LastStoreSize - SplitAfterOffset;
541 assert(!SplitAfterSize.isNegative() && "negative store size!");
542 if (!SplitAfterSize.isZero())
543 Stores.emplace_back(SplitAfterOffset, SplitAfterSize);
544 }
545
546 // If the type contains a pointer to data member we can't memset it to zero.
547 // Instead, create a null constant and copy it to the destination.
548 // TODO: there are other patterns besides zero that we can usefully memset,
549 // like -1, which happens to be the pattern used by member-pointers.
550 // TODO: isZeroInitializable can be over-conservative in the case where a
551 // virtual base contains a member pointer.
552 llvm::Constant *NullConstantForBase = CGF.CGM.EmitNullConstantForBase(Base);
553 if (!NullConstantForBase->isNullValue()) {
554 llvm::GlobalVariable *NullVariable = new llvm::GlobalVariable(
555 CGF.CGM.getModule(), NullConstantForBase->getType(),
556 /*isConstant=*/true, llvm::GlobalVariable::PrivateLinkage,
557 NullConstantForBase, Twine());
558
559 CharUnits Align =
560 std::max(Layout.getNonVirtualAlignment(), DestPtr.getAlignment());
561 NullVariable->setAlignment(Align.getAsAlign());
562
563 Address SrcPtr(NullVariable, CGF.Int8Ty, Align);
564
565 // Get and call the appropriate llvm.memcpy overload.
566 for (std::pair<CharUnits, CharUnits> Store : Stores) {
567 CharUnits StoreOffset = Store.first;
568 CharUnits StoreSize = Store.second;
569 llvm::Value *StoreSizeVal = CGF.CGM.getSize(StoreSize);
570 CGF.Builder.CreateMemCpy(
571 CGF.Builder.CreateConstInBoundsByteGEP(DestPtr, StoreOffset),
572 CGF.Builder.CreateConstInBoundsByteGEP(SrcPtr, StoreOffset),
573 StoreSizeVal);
574 }
575
576 // Otherwise, just memset the whole thing to zero. This is legal
577 // because in LLVM, all default initializers (other than the ones we just
578 // handled above) are guaranteed to have a bit pattern of all zeros.
579 } else {
580 for (std::pair<CharUnits, CharUnits> Store : Stores) {
581 CharUnits StoreOffset = Store.first;
582 CharUnits StoreSize = Store.second;
583 llvm::Value *StoreSizeVal = CGF.CGM.getSize(StoreSize);
584 CGF.Builder.CreateMemSet(
585 CGF.Builder.CreateConstInBoundsByteGEP(DestPtr, StoreOffset),
586 CGF.Builder.getInt8(0), StoreSizeVal);
587 }
588 }
589 }
590
591 void
EmitCXXConstructExpr(const CXXConstructExpr * E,AggValueSlot Dest)592 CodeGenFunction::EmitCXXConstructExpr(const CXXConstructExpr *E,
593 AggValueSlot Dest) {
594 assert(!Dest.isIgnored() && "Must have a destination!");
595 const CXXConstructorDecl *CD = E->getConstructor();
596
597 // If we require zero initialization before (or instead of) calling the
598 // constructor, as can be the case with a non-user-provided default
599 // constructor, emit the zero initialization now, unless destination is
600 // already zeroed.
601 if (E->requiresZeroInitialization() && !Dest.isZeroed()) {
602 switch (E->getConstructionKind()) {
603 case CXXConstructionKind::Delegating:
604 case CXXConstructionKind::Complete:
605 EmitNullInitialization(Dest.getAddress(), E->getType());
606 break;
607 case CXXConstructionKind::VirtualBase:
608 case CXXConstructionKind::NonVirtualBase:
609 EmitNullBaseClassInitialization(*this, Dest.getAddress(),
610 CD->getParent());
611 break;
612 }
613 }
614
615 // If this is a call to a trivial default constructor, do nothing.
616 if (CD->isTrivial() && CD->isDefaultConstructor())
617 return;
618
619 // Elide the constructor if we're constructing from a temporary.
620 if (getLangOpts().ElideConstructors && E->isElidable()) {
621 // FIXME: This only handles the simplest case, where the source object
622 // is passed directly as the first argument to the constructor.
623 // This should also handle stepping though implicit casts and
624 // conversion sequences which involve two steps, with a
625 // conversion operator followed by a converting constructor.
626 const Expr *SrcObj = E->getArg(0);
627 assert(SrcObj->isTemporaryObject(getContext(), CD->getParent()));
628 assert(
629 getContext().hasSameUnqualifiedType(E->getType(), SrcObj->getType()));
630 EmitAggExpr(SrcObj, Dest);
631 return;
632 }
633
634 if (const ArrayType *arrayType
635 = getContext().getAsArrayType(E->getType())) {
636 EmitCXXAggrConstructorCall(CD, arrayType, Dest.getAddress(), E,
637 Dest.isSanitizerChecked());
638 } else {
639 CXXCtorType Type = Ctor_Complete;
640 bool ForVirtualBase = false;
641 bool Delegating = false;
642
643 switch (E->getConstructionKind()) {
644 case CXXConstructionKind::Delegating:
645 // We should be emitting a constructor; GlobalDecl will assert this
646 Type = CurGD.getCtorType();
647 Delegating = true;
648 break;
649
650 case CXXConstructionKind::Complete:
651 Type = Ctor_Complete;
652 break;
653
654 case CXXConstructionKind::VirtualBase:
655 ForVirtualBase = true;
656 [[fallthrough]];
657
658 case CXXConstructionKind::NonVirtualBase:
659 Type = Ctor_Base;
660 }
661
662 // Call the constructor.
663 EmitCXXConstructorCall(CD, Type, ForVirtualBase, Delegating, Dest, E);
664 }
665 }
666
EmitSynthesizedCXXCopyCtor(Address Dest,Address Src,const Expr * Exp)667 void CodeGenFunction::EmitSynthesizedCXXCopyCtor(Address Dest, Address Src,
668 const Expr *Exp) {
669 if (const ExprWithCleanups *E = dyn_cast<ExprWithCleanups>(Exp))
670 Exp = E->getSubExpr();
671 assert(isa<CXXConstructExpr>(Exp) &&
672 "EmitSynthesizedCXXCopyCtor - unknown copy ctor expr");
673 const CXXConstructExpr* E = cast<CXXConstructExpr>(Exp);
674 const CXXConstructorDecl *CD = E->getConstructor();
675 RunCleanupsScope Scope(*this);
676
677 // If we require zero initialization before (or instead of) calling the
678 // constructor, as can be the case with a non-user-provided default
679 // constructor, emit the zero initialization now.
680 // FIXME. Do I still need this for a copy ctor synthesis?
681 if (E->requiresZeroInitialization())
682 EmitNullInitialization(Dest, E->getType());
683
684 assert(!getContext().getAsConstantArrayType(E->getType())
685 && "EmitSynthesizedCXXCopyCtor - Copied-in Array");
686 EmitSynthesizedCXXCopyCtorCall(CD, Dest, Src, E);
687 }
688
CalculateCookiePadding(CodeGenFunction & CGF,const CXXNewExpr * E)689 static CharUnits CalculateCookiePadding(CodeGenFunction &CGF,
690 const CXXNewExpr *E) {
691 if (!E->isArray())
692 return CharUnits::Zero();
693
694 // No cookie is required if the operator new[] being used is the
695 // reserved placement operator new[].
696 if (E->getOperatorNew()->isReservedGlobalPlacementOperator())
697 return CharUnits::Zero();
698
699 return CGF.CGM.getCXXABI().GetArrayCookieSize(E);
700 }
701
EmitCXXNewAllocSize(CodeGenFunction & CGF,const CXXNewExpr * e,unsigned minElements,llvm::Value * & numElements,llvm::Value * & sizeWithoutCookie)702 static llvm::Value *EmitCXXNewAllocSize(CodeGenFunction &CGF,
703 const CXXNewExpr *e,
704 unsigned minElements,
705 llvm::Value *&numElements,
706 llvm::Value *&sizeWithoutCookie) {
707 QualType type = e->getAllocatedType();
708
709 if (!e->isArray()) {
710 CharUnits typeSize = CGF.getContext().getTypeSizeInChars(type);
711 sizeWithoutCookie
712 = llvm::ConstantInt::get(CGF.SizeTy, typeSize.getQuantity());
713 return sizeWithoutCookie;
714 }
715
716 // The width of size_t.
717 unsigned sizeWidth = CGF.SizeTy->getBitWidth();
718
719 // Figure out the cookie size.
720 llvm::APInt cookieSize(sizeWidth,
721 CalculateCookiePadding(CGF, e).getQuantity());
722
723 // Emit the array size expression.
724 // We multiply the size of all dimensions for NumElements.
725 // e.g for 'int[2][3]', ElemType is 'int' and NumElements is 6.
726 numElements =
727 ConstantEmitter(CGF).tryEmitAbstract(*e->getArraySize(), e->getType());
728 if (!numElements)
729 numElements = CGF.EmitScalarExpr(*e->getArraySize());
730 assert(isa<llvm::IntegerType>(numElements->getType()));
731
732 // The number of elements can be have an arbitrary integer type;
733 // essentially, we need to multiply it by a constant factor, add a
734 // cookie size, and verify that the result is representable as a
735 // size_t. That's just a gloss, though, and it's wrong in one
736 // important way: if the count is negative, it's an error even if
737 // the cookie size would bring the total size >= 0.
738 bool isSigned
739 = (*e->getArraySize())->getType()->isSignedIntegerOrEnumerationType();
740 llvm::IntegerType *numElementsType
741 = cast<llvm::IntegerType>(numElements->getType());
742 unsigned numElementsWidth = numElementsType->getBitWidth();
743
744 // Compute the constant factor.
745 llvm::APInt arraySizeMultiplier(sizeWidth, 1);
746 while (const ConstantArrayType *CAT
747 = CGF.getContext().getAsConstantArrayType(type)) {
748 type = CAT->getElementType();
749 arraySizeMultiplier *= CAT->getSize();
750 }
751
752 CharUnits typeSize = CGF.getContext().getTypeSizeInChars(type);
753 llvm::APInt typeSizeMultiplier(sizeWidth, typeSize.getQuantity());
754 typeSizeMultiplier *= arraySizeMultiplier;
755
756 // This will be a size_t.
757 llvm::Value *size;
758
759 // If someone is doing 'new int[42]' there is no need to do a dynamic check.
760 // Don't bloat the -O0 code.
761 if (llvm::ConstantInt *numElementsC =
762 dyn_cast<llvm::ConstantInt>(numElements)) {
763 const llvm::APInt &count = numElementsC->getValue();
764
765 bool hasAnyOverflow = false;
766
767 // If 'count' was a negative number, it's an overflow.
768 if (isSigned && count.isNegative())
769 hasAnyOverflow = true;
770
771 // We want to do all this arithmetic in size_t. If numElements is
772 // wider than that, check whether it's already too big, and if so,
773 // overflow.
774 else if (numElementsWidth > sizeWidth &&
775 numElementsWidth - sizeWidth > count.countl_zero())
776 hasAnyOverflow = true;
777
778 // Okay, compute a count at the right width.
779 llvm::APInt adjustedCount = count.zextOrTrunc(sizeWidth);
780
781 // If there is a brace-initializer, we cannot allocate fewer elements than
782 // there are initializers. If we do, that's treated like an overflow.
783 if (adjustedCount.ult(minElements))
784 hasAnyOverflow = true;
785
786 // Scale numElements by that. This might overflow, but we don't
787 // care because it only overflows if allocationSize does, too, and
788 // if that overflows then we shouldn't use this.
789 numElements = llvm::ConstantInt::get(CGF.SizeTy,
790 adjustedCount * arraySizeMultiplier);
791
792 // Compute the size before cookie, and track whether it overflowed.
793 bool overflow;
794 llvm::APInt allocationSize
795 = adjustedCount.umul_ov(typeSizeMultiplier, overflow);
796 hasAnyOverflow |= overflow;
797
798 // Add in the cookie, and check whether it's overflowed.
799 if (cookieSize != 0) {
800 // Save the current size without a cookie. This shouldn't be
801 // used if there was overflow.
802 sizeWithoutCookie = llvm::ConstantInt::get(CGF.SizeTy, allocationSize);
803
804 allocationSize = allocationSize.uadd_ov(cookieSize, overflow);
805 hasAnyOverflow |= overflow;
806 }
807
808 // On overflow, produce a -1 so operator new will fail.
809 if (hasAnyOverflow) {
810 size = llvm::Constant::getAllOnesValue(CGF.SizeTy);
811 } else {
812 size = llvm::ConstantInt::get(CGF.SizeTy, allocationSize);
813 }
814
815 // Otherwise, we might need to use the overflow intrinsics.
816 } else {
817 // There are up to five conditions we need to test for:
818 // 1) if isSigned, we need to check whether numElements is negative;
819 // 2) if numElementsWidth > sizeWidth, we need to check whether
820 // numElements is larger than something representable in size_t;
821 // 3) if minElements > 0, we need to check whether numElements is smaller
822 // than that.
823 // 4) we need to compute
824 // sizeWithoutCookie := numElements * typeSizeMultiplier
825 // and check whether it overflows; and
826 // 5) if we need a cookie, we need to compute
827 // size := sizeWithoutCookie + cookieSize
828 // and check whether it overflows.
829
830 llvm::Value *hasOverflow = nullptr;
831
832 // If numElementsWidth > sizeWidth, then one way or another, we're
833 // going to have to do a comparison for (2), and this happens to
834 // take care of (1), too.
835 if (numElementsWidth > sizeWidth) {
836 llvm::APInt threshold =
837 llvm::APInt::getOneBitSet(numElementsWidth, sizeWidth);
838
839 llvm::Value *thresholdV
840 = llvm::ConstantInt::get(numElementsType, threshold);
841
842 hasOverflow = CGF.Builder.CreateICmpUGE(numElements, thresholdV);
843 numElements = CGF.Builder.CreateTrunc(numElements, CGF.SizeTy);
844
845 // Otherwise, if we're signed, we want to sext up to size_t.
846 } else if (isSigned) {
847 if (numElementsWidth < sizeWidth)
848 numElements = CGF.Builder.CreateSExt(numElements, CGF.SizeTy);
849
850 // If there's a non-1 type size multiplier, then we can do the
851 // signedness check at the same time as we do the multiply
852 // because a negative number times anything will cause an
853 // unsigned overflow. Otherwise, we have to do it here. But at least
854 // in this case, we can subsume the >= minElements check.
855 if (typeSizeMultiplier == 1)
856 hasOverflow = CGF.Builder.CreateICmpSLT(numElements,
857 llvm::ConstantInt::get(CGF.SizeTy, minElements));
858
859 // Otherwise, zext up to size_t if necessary.
860 } else if (numElementsWidth < sizeWidth) {
861 numElements = CGF.Builder.CreateZExt(numElements, CGF.SizeTy);
862 }
863
864 assert(numElements->getType() == CGF.SizeTy);
865
866 if (minElements) {
867 // Don't allow allocation of fewer elements than we have initializers.
868 if (!hasOverflow) {
869 hasOverflow = CGF.Builder.CreateICmpULT(numElements,
870 llvm::ConstantInt::get(CGF.SizeTy, minElements));
871 } else if (numElementsWidth > sizeWidth) {
872 // The other existing overflow subsumes this check.
873 // We do an unsigned comparison, since any signed value < -1 is
874 // taken care of either above or below.
875 hasOverflow = CGF.Builder.CreateOr(hasOverflow,
876 CGF.Builder.CreateICmpULT(numElements,
877 llvm::ConstantInt::get(CGF.SizeTy, minElements)));
878 }
879 }
880
881 size = numElements;
882
883 // Multiply by the type size if necessary. This multiplier
884 // includes all the factors for nested arrays.
885 //
886 // This step also causes numElements to be scaled up by the
887 // nested-array factor if necessary. Overflow on this computation
888 // can be ignored because the result shouldn't be used if
889 // allocation fails.
890 if (typeSizeMultiplier != 1) {
891 llvm::Function *umul_with_overflow
892 = CGF.CGM.getIntrinsic(llvm::Intrinsic::umul_with_overflow, CGF.SizeTy);
893
894 llvm::Value *tsmV =
895 llvm::ConstantInt::get(CGF.SizeTy, typeSizeMultiplier);
896 llvm::Value *result =
897 CGF.Builder.CreateCall(umul_with_overflow, {size, tsmV});
898
899 llvm::Value *overflowed = CGF.Builder.CreateExtractValue(result, 1);
900 if (hasOverflow)
901 hasOverflow = CGF.Builder.CreateOr(hasOverflow, overflowed);
902 else
903 hasOverflow = overflowed;
904
905 size = CGF.Builder.CreateExtractValue(result, 0);
906
907 // Also scale up numElements by the array size multiplier.
908 if (arraySizeMultiplier != 1) {
909 // If the base element type size is 1, then we can re-use the
910 // multiply we just did.
911 if (typeSize.isOne()) {
912 assert(arraySizeMultiplier == typeSizeMultiplier);
913 numElements = size;
914
915 // Otherwise we need a separate multiply.
916 } else {
917 llvm::Value *asmV =
918 llvm::ConstantInt::get(CGF.SizeTy, arraySizeMultiplier);
919 numElements = CGF.Builder.CreateMul(numElements, asmV);
920 }
921 }
922 } else {
923 // numElements doesn't need to be scaled.
924 assert(arraySizeMultiplier == 1);
925 }
926
927 // Add in the cookie size if necessary.
928 if (cookieSize != 0) {
929 sizeWithoutCookie = size;
930
931 llvm::Function *uadd_with_overflow
932 = CGF.CGM.getIntrinsic(llvm::Intrinsic::uadd_with_overflow, CGF.SizeTy);
933
934 llvm::Value *cookieSizeV = llvm::ConstantInt::get(CGF.SizeTy, cookieSize);
935 llvm::Value *result =
936 CGF.Builder.CreateCall(uadd_with_overflow, {size, cookieSizeV});
937
938 llvm::Value *overflowed = CGF.Builder.CreateExtractValue(result, 1);
939 if (hasOverflow)
940 hasOverflow = CGF.Builder.CreateOr(hasOverflow, overflowed);
941 else
942 hasOverflow = overflowed;
943
944 size = CGF.Builder.CreateExtractValue(result, 0);
945 }
946
947 // If we had any possibility of dynamic overflow, make a select to
948 // overwrite 'size' with an all-ones value, which should cause
949 // operator new to throw.
950 if (hasOverflow)
951 size = CGF.Builder.CreateSelect(hasOverflow,
952 llvm::Constant::getAllOnesValue(CGF.SizeTy),
953 size);
954 }
955
956 if (cookieSize == 0)
957 sizeWithoutCookie = size;
958 else
959 assert(sizeWithoutCookie && "didn't set sizeWithoutCookie?");
960
961 return size;
962 }
963
StoreAnyExprIntoOneUnit(CodeGenFunction & CGF,const Expr * Init,QualType AllocType,Address NewPtr,AggValueSlot::Overlap_t MayOverlap)964 static void StoreAnyExprIntoOneUnit(CodeGenFunction &CGF, const Expr *Init,
965 QualType AllocType, Address NewPtr,
966 AggValueSlot::Overlap_t MayOverlap) {
967 // FIXME: Refactor with EmitExprAsInit.
968 switch (CGF.getEvaluationKind(AllocType)) {
969 case TEK_Scalar:
970 CGF.EmitScalarInit(Init, nullptr,
971 CGF.MakeAddrLValue(NewPtr, AllocType), false);
972 return;
973 case TEK_Complex:
974 CGF.EmitComplexExprIntoLValue(Init, CGF.MakeAddrLValue(NewPtr, AllocType),
975 /*isInit*/ true);
976 return;
977 case TEK_Aggregate: {
978 AggValueSlot Slot
979 = AggValueSlot::forAddr(NewPtr, AllocType.getQualifiers(),
980 AggValueSlot::IsDestructed,
981 AggValueSlot::DoesNotNeedGCBarriers,
982 AggValueSlot::IsNotAliased,
983 MayOverlap, AggValueSlot::IsNotZeroed,
984 AggValueSlot::IsSanitizerChecked);
985 CGF.EmitAggExpr(Init, Slot);
986 return;
987 }
988 }
989 llvm_unreachable("bad evaluation kind");
990 }
991
EmitNewArrayInitializer(const CXXNewExpr * E,QualType ElementType,llvm::Type * ElementTy,Address BeginPtr,llvm::Value * NumElements,llvm::Value * AllocSizeWithoutCookie)992 void CodeGenFunction::EmitNewArrayInitializer(
993 const CXXNewExpr *E, QualType ElementType, llvm::Type *ElementTy,
994 Address BeginPtr, llvm::Value *NumElements,
995 llvm::Value *AllocSizeWithoutCookie) {
996 // If we have a type with trivial initialization and no initializer,
997 // there's nothing to do.
998 if (!E->hasInitializer())
999 return;
1000
1001 Address CurPtr = BeginPtr;
1002
1003 unsigned InitListElements = 0;
1004
1005 const Expr *Init = E->getInitializer();
1006 Address EndOfInit = Address::invalid();
1007 QualType::DestructionKind DtorKind = ElementType.isDestructedType();
1008 EHScopeStack::stable_iterator Cleanup;
1009 llvm::Instruction *CleanupDominator = nullptr;
1010
1011 CharUnits ElementSize = getContext().getTypeSizeInChars(ElementType);
1012 CharUnits ElementAlign =
1013 BeginPtr.getAlignment().alignmentOfArrayElement(ElementSize);
1014
1015 // Attempt to perform zero-initialization using memset.
1016 auto TryMemsetInitialization = [&]() -> bool {
1017 // FIXME: If the type is a pointer-to-data-member under the Itanium ABI,
1018 // we can initialize with a memset to -1.
1019 if (!CGM.getTypes().isZeroInitializable(ElementType))
1020 return false;
1021
1022 // Optimization: since zero initialization will just set the memory
1023 // to all zeroes, generate a single memset to do it in one shot.
1024
1025 // Subtract out the size of any elements we've already initialized.
1026 auto *RemainingSize = AllocSizeWithoutCookie;
1027 if (InitListElements) {
1028 // We know this can't overflow; we check this when doing the allocation.
1029 auto *InitializedSize = llvm::ConstantInt::get(
1030 RemainingSize->getType(),
1031 getContext().getTypeSizeInChars(ElementType).getQuantity() *
1032 InitListElements);
1033 RemainingSize = Builder.CreateSub(RemainingSize, InitializedSize);
1034 }
1035
1036 // Create the memset.
1037 Builder.CreateMemSet(CurPtr, Builder.getInt8(0), RemainingSize, false);
1038 return true;
1039 };
1040
1041 const InitListExpr *ILE = dyn_cast<InitListExpr>(Init);
1042 const CXXParenListInitExpr *CPLIE = nullptr;
1043 const StringLiteral *SL = nullptr;
1044 const ObjCEncodeExpr *OCEE = nullptr;
1045 const Expr *IgnoreParen = nullptr;
1046 if (!ILE) {
1047 IgnoreParen = Init->IgnoreParenImpCasts();
1048 CPLIE = dyn_cast<CXXParenListInitExpr>(IgnoreParen);
1049 SL = dyn_cast<StringLiteral>(IgnoreParen);
1050 OCEE = dyn_cast<ObjCEncodeExpr>(IgnoreParen);
1051 }
1052
1053 // If the initializer is an initializer list, first do the explicit elements.
1054 if (ILE || CPLIE || SL || OCEE) {
1055 // Initializing from a (braced) string literal is a special case; the init
1056 // list element does not initialize a (single) array element.
1057 if ((ILE && ILE->isStringLiteralInit()) || SL || OCEE) {
1058 if (!ILE)
1059 Init = IgnoreParen;
1060 // Initialize the initial portion of length equal to that of the string
1061 // literal. The allocation must be for at least this much; we emitted a
1062 // check for that earlier.
1063 AggValueSlot Slot =
1064 AggValueSlot::forAddr(CurPtr, ElementType.getQualifiers(),
1065 AggValueSlot::IsDestructed,
1066 AggValueSlot::DoesNotNeedGCBarriers,
1067 AggValueSlot::IsNotAliased,
1068 AggValueSlot::DoesNotOverlap,
1069 AggValueSlot::IsNotZeroed,
1070 AggValueSlot::IsSanitizerChecked);
1071 EmitAggExpr(ILE ? ILE->getInit(0) : Init, Slot);
1072
1073 // Move past these elements.
1074 InitListElements =
1075 cast<ConstantArrayType>(Init->getType()->getAsArrayTypeUnsafe())
1076 ->getSize()
1077 .getZExtValue();
1078 CurPtr = Builder.CreateConstInBoundsGEP(
1079 CurPtr, InitListElements, "string.init.end");
1080
1081 // Zero out the rest, if any remain.
1082 llvm::ConstantInt *ConstNum = dyn_cast<llvm::ConstantInt>(NumElements);
1083 if (!ConstNum || !ConstNum->equalsInt(InitListElements)) {
1084 bool OK = TryMemsetInitialization();
1085 (void)OK;
1086 assert(OK && "couldn't memset character type?");
1087 }
1088 return;
1089 }
1090
1091 ArrayRef<const Expr *> InitExprs =
1092 ILE ? ILE->inits() : CPLIE->getInitExprs();
1093 InitListElements = InitExprs.size();
1094
1095 // If this is a multi-dimensional array new, we will initialize multiple
1096 // elements with each init list element.
1097 QualType AllocType = E->getAllocatedType();
1098 if (const ConstantArrayType *CAT = dyn_cast_or_null<ConstantArrayType>(
1099 AllocType->getAsArrayTypeUnsafe())) {
1100 ElementTy = ConvertTypeForMem(AllocType);
1101 CurPtr = CurPtr.withElementType(ElementTy);
1102 InitListElements *= getContext().getConstantArrayElementCount(CAT);
1103 }
1104
1105 // Enter a partial-destruction Cleanup if necessary.
1106 if (needsEHCleanup(DtorKind)) {
1107 // In principle we could tell the Cleanup where we are more
1108 // directly, but the control flow can get so varied here that it
1109 // would actually be quite complex. Therefore we go through an
1110 // alloca.
1111 EndOfInit = CreateTempAlloca(BeginPtr.getType(), getPointerAlign(),
1112 "array.init.end");
1113 CleanupDominator = Builder.CreateStore(BeginPtr.getPointer(), EndOfInit);
1114 pushIrregularPartialArrayCleanup(BeginPtr.getPointer(), EndOfInit,
1115 ElementType, ElementAlign,
1116 getDestroyer(DtorKind));
1117 Cleanup = EHStack.stable_begin();
1118 }
1119
1120 CharUnits StartAlign = CurPtr.getAlignment();
1121 unsigned i = 0;
1122 for (const Expr *IE : InitExprs) {
1123 // Tell the cleanup that it needs to destroy up to this
1124 // element. TODO: some of these stores can be trivially
1125 // observed to be unnecessary.
1126 if (EndOfInit.isValid()) {
1127 Builder.CreateStore(CurPtr.getPointer(), EndOfInit);
1128 }
1129 // FIXME: If the last initializer is an incomplete initializer list for
1130 // an array, and we have an array filler, we can fold together the two
1131 // initialization loops.
1132 StoreAnyExprIntoOneUnit(*this, IE, IE->getType(), CurPtr,
1133 AggValueSlot::DoesNotOverlap);
1134 CurPtr = Address(Builder.CreateInBoundsGEP(
1135 CurPtr.getElementType(), CurPtr.getPointer(),
1136 Builder.getSize(1), "array.exp.next"),
1137 CurPtr.getElementType(),
1138 StartAlign.alignmentAtOffset((++i) * ElementSize));
1139 }
1140
1141 // The remaining elements are filled with the array filler expression.
1142 Init = ILE ? ILE->getArrayFiller() : CPLIE->getArrayFiller();
1143
1144 // Extract the initializer for the individual array elements by pulling
1145 // out the array filler from all the nested initializer lists. This avoids
1146 // generating a nested loop for the initialization.
1147 while (Init && Init->getType()->isConstantArrayType()) {
1148 auto *SubILE = dyn_cast<InitListExpr>(Init);
1149 if (!SubILE)
1150 break;
1151 assert(SubILE->getNumInits() == 0 && "explicit inits in array filler?");
1152 Init = SubILE->getArrayFiller();
1153 }
1154
1155 // Switch back to initializing one base element at a time.
1156 CurPtr = CurPtr.withElementType(BeginPtr.getElementType());
1157 }
1158
1159 // If all elements have already been initialized, skip any further
1160 // initialization.
1161 llvm::ConstantInt *ConstNum = dyn_cast<llvm::ConstantInt>(NumElements);
1162 if (ConstNum && ConstNum->getZExtValue() <= InitListElements) {
1163 // If there was a Cleanup, deactivate it.
1164 if (CleanupDominator)
1165 DeactivateCleanupBlock(Cleanup, CleanupDominator);
1166 return;
1167 }
1168
1169 assert(Init && "have trailing elements to initialize but no initializer");
1170
1171 // If this is a constructor call, try to optimize it out, and failing that
1172 // emit a single loop to initialize all remaining elements.
1173 if (const CXXConstructExpr *CCE = dyn_cast<CXXConstructExpr>(Init)) {
1174 CXXConstructorDecl *Ctor = CCE->getConstructor();
1175 if (Ctor->isTrivial()) {
1176 // If new expression did not specify value-initialization, then there
1177 // is no initialization.
1178 if (!CCE->requiresZeroInitialization() || Ctor->getParent()->isEmpty())
1179 return;
1180
1181 if (TryMemsetInitialization())
1182 return;
1183 }
1184
1185 // Store the new Cleanup position for irregular Cleanups.
1186 //
1187 // FIXME: Share this cleanup with the constructor call emission rather than
1188 // having it create a cleanup of its own.
1189 if (EndOfInit.isValid())
1190 Builder.CreateStore(CurPtr.getPointer(), EndOfInit);
1191
1192 // Emit a constructor call loop to initialize the remaining elements.
1193 if (InitListElements)
1194 NumElements = Builder.CreateSub(
1195 NumElements,
1196 llvm::ConstantInt::get(NumElements->getType(), InitListElements));
1197 EmitCXXAggrConstructorCall(Ctor, NumElements, CurPtr, CCE,
1198 /*NewPointerIsChecked*/true,
1199 CCE->requiresZeroInitialization());
1200 return;
1201 }
1202
1203 // If this is value-initialization, we can usually use memset.
1204 ImplicitValueInitExpr IVIE(ElementType);
1205 if (isa<ImplicitValueInitExpr>(Init)) {
1206 if (TryMemsetInitialization())
1207 return;
1208
1209 // Switch to an ImplicitValueInitExpr for the element type. This handles
1210 // only one case: multidimensional array new of pointers to members. In
1211 // all other cases, we already have an initializer for the array element.
1212 Init = &IVIE;
1213 }
1214
1215 // At this point we should have found an initializer for the individual
1216 // elements of the array.
1217 assert(getContext().hasSameUnqualifiedType(ElementType, Init->getType()) &&
1218 "got wrong type of element to initialize");
1219
1220 // If we have an empty initializer list, we can usually use memset.
1221 if (auto *ILE = dyn_cast<InitListExpr>(Init))
1222 if (ILE->getNumInits() == 0 && TryMemsetInitialization())
1223 return;
1224
1225 // If we have a struct whose every field is value-initialized, we can
1226 // usually use memset.
1227 if (auto *ILE = dyn_cast<InitListExpr>(Init)) {
1228 if (const RecordType *RType = ILE->getType()->getAs<RecordType>()) {
1229 if (RType->getDecl()->isStruct()) {
1230 unsigned NumElements = 0;
1231 if (auto *CXXRD = dyn_cast<CXXRecordDecl>(RType->getDecl()))
1232 NumElements = CXXRD->getNumBases();
1233 for (auto *Field : RType->getDecl()->fields())
1234 if (!Field->isUnnamedBitfield())
1235 ++NumElements;
1236 // FIXME: Recurse into nested InitListExprs.
1237 if (ILE->getNumInits() == NumElements)
1238 for (unsigned i = 0, e = ILE->getNumInits(); i != e; ++i)
1239 if (!isa<ImplicitValueInitExpr>(ILE->getInit(i)))
1240 --NumElements;
1241 if (ILE->getNumInits() == NumElements && TryMemsetInitialization())
1242 return;
1243 }
1244 }
1245 }
1246
1247 // Create the loop blocks.
1248 llvm::BasicBlock *EntryBB = Builder.GetInsertBlock();
1249 llvm::BasicBlock *LoopBB = createBasicBlock("new.loop");
1250 llvm::BasicBlock *ContBB = createBasicBlock("new.loop.end");
1251
1252 // Find the end of the array, hoisted out of the loop.
1253 llvm::Value *EndPtr =
1254 Builder.CreateInBoundsGEP(BeginPtr.getElementType(), BeginPtr.getPointer(),
1255 NumElements, "array.end");
1256
1257 // If the number of elements isn't constant, we have to now check if there is
1258 // anything left to initialize.
1259 if (!ConstNum) {
1260 llvm::Value *IsEmpty =
1261 Builder.CreateICmpEQ(CurPtr.getPointer(), EndPtr, "array.isempty");
1262 Builder.CreateCondBr(IsEmpty, ContBB, LoopBB);
1263 }
1264
1265 // Enter the loop.
1266 EmitBlock(LoopBB);
1267
1268 // Set up the current-element phi.
1269 llvm::PHINode *CurPtrPhi =
1270 Builder.CreatePHI(CurPtr.getType(), 2, "array.cur");
1271 CurPtrPhi->addIncoming(CurPtr.getPointer(), EntryBB);
1272
1273 CurPtr = Address(CurPtrPhi, CurPtr.getElementType(), ElementAlign);
1274
1275 // Store the new Cleanup position for irregular Cleanups.
1276 if (EndOfInit.isValid())
1277 Builder.CreateStore(CurPtr.getPointer(), EndOfInit);
1278
1279 // Enter a partial-destruction Cleanup if necessary.
1280 if (!CleanupDominator && needsEHCleanup(DtorKind)) {
1281 pushRegularPartialArrayCleanup(BeginPtr.getPointer(), CurPtr.getPointer(),
1282 ElementType, ElementAlign,
1283 getDestroyer(DtorKind));
1284 Cleanup = EHStack.stable_begin();
1285 CleanupDominator = Builder.CreateUnreachable();
1286 }
1287
1288 // Emit the initializer into this element.
1289 StoreAnyExprIntoOneUnit(*this, Init, Init->getType(), CurPtr,
1290 AggValueSlot::DoesNotOverlap);
1291
1292 // Leave the Cleanup if we entered one.
1293 if (CleanupDominator) {
1294 DeactivateCleanupBlock(Cleanup, CleanupDominator);
1295 CleanupDominator->eraseFromParent();
1296 }
1297
1298 // Advance to the next element by adjusting the pointer type as necessary.
1299 llvm::Value *NextPtr =
1300 Builder.CreateConstInBoundsGEP1_32(ElementTy, CurPtr.getPointer(), 1,
1301 "array.next");
1302
1303 // Check whether we've gotten to the end of the array and, if so,
1304 // exit the loop.
1305 llvm::Value *IsEnd = Builder.CreateICmpEQ(NextPtr, EndPtr, "array.atend");
1306 Builder.CreateCondBr(IsEnd, ContBB, LoopBB);
1307 CurPtrPhi->addIncoming(NextPtr, Builder.GetInsertBlock());
1308
1309 EmitBlock(ContBB);
1310 }
1311
EmitNewInitializer(CodeGenFunction & CGF,const CXXNewExpr * E,QualType ElementType,llvm::Type * ElementTy,Address NewPtr,llvm::Value * NumElements,llvm::Value * AllocSizeWithoutCookie)1312 static void EmitNewInitializer(CodeGenFunction &CGF, const CXXNewExpr *E,
1313 QualType ElementType, llvm::Type *ElementTy,
1314 Address NewPtr, llvm::Value *NumElements,
1315 llvm::Value *AllocSizeWithoutCookie) {
1316 ApplyDebugLocation DL(CGF, E);
1317 if (E->isArray())
1318 CGF.EmitNewArrayInitializer(E, ElementType, ElementTy, NewPtr, NumElements,
1319 AllocSizeWithoutCookie);
1320 else if (const Expr *Init = E->getInitializer())
1321 StoreAnyExprIntoOneUnit(CGF, Init, E->getAllocatedType(), NewPtr,
1322 AggValueSlot::DoesNotOverlap);
1323 }
1324
1325 /// Emit a call to an operator new or operator delete function, as implicitly
1326 /// created by new-expressions and delete-expressions.
EmitNewDeleteCall(CodeGenFunction & CGF,const FunctionDecl * CalleeDecl,const FunctionProtoType * CalleeType,const CallArgList & Args)1327 static RValue EmitNewDeleteCall(CodeGenFunction &CGF,
1328 const FunctionDecl *CalleeDecl,
1329 const FunctionProtoType *CalleeType,
1330 const CallArgList &Args) {
1331 llvm::CallBase *CallOrInvoke;
1332 llvm::Constant *CalleePtr = CGF.CGM.GetAddrOfFunction(CalleeDecl);
1333 CGCallee Callee = CGCallee::forDirect(CalleePtr, GlobalDecl(CalleeDecl));
1334 RValue RV =
1335 CGF.EmitCall(CGF.CGM.getTypes().arrangeFreeFunctionCall(
1336 Args, CalleeType, /*ChainCall=*/false),
1337 Callee, ReturnValueSlot(), Args, &CallOrInvoke);
1338
1339 /// C++1y [expr.new]p10:
1340 /// [In a new-expression,] an implementation is allowed to omit a call
1341 /// to a replaceable global allocation function.
1342 ///
1343 /// We model such elidable calls with the 'builtin' attribute.
1344 llvm::Function *Fn = dyn_cast<llvm::Function>(CalleePtr);
1345 if (CalleeDecl->isReplaceableGlobalAllocationFunction() &&
1346 Fn && Fn->hasFnAttribute(llvm::Attribute::NoBuiltin)) {
1347 CallOrInvoke->addFnAttr(llvm::Attribute::Builtin);
1348 }
1349
1350 return RV;
1351 }
1352
EmitBuiltinNewDeleteCall(const FunctionProtoType * Type,const CallExpr * TheCall,bool IsDelete)1353 RValue CodeGenFunction::EmitBuiltinNewDeleteCall(const FunctionProtoType *Type,
1354 const CallExpr *TheCall,
1355 bool IsDelete) {
1356 CallArgList Args;
1357 EmitCallArgs(Args, Type, TheCall->arguments());
1358 // Find the allocation or deallocation function that we're calling.
1359 ASTContext &Ctx = getContext();
1360 DeclarationName Name = Ctx.DeclarationNames
1361 .getCXXOperatorName(IsDelete ? OO_Delete : OO_New);
1362
1363 for (auto *Decl : Ctx.getTranslationUnitDecl()->lookup(Name))
1364 if (auto *FD = dyn_cast<FunctionDecl>(Decl))
1365 if (Ctx.hasSameType(FD->getType(), QualType(Type, 0)))
1366 return EmitNewDeleteCall(*this, FD, Type, Args);
1367 llvm_unreachable("predeclared global operator new/delete is missing");
1368 }
1369
1370 namespace {
1371 /// The parameters to pass to a usual operator delete.
1372 struct UsualDeleteParams {
1373 bool DestroyingDelete = false;
1374 bool Size = false;
1375 bool Alignment = false;
1376 };
1377 }
1378
getUsualDeleteParams(const FunctionDecl * FD)1379 static UsualDeleteParams getUsualDeleteParams(const FunctionDecl *FD) {
1380 UsualDeleteParams Params;
1381
1382 const FunctionProtoType *FPT = FD->getType()->castAs<FunctionProtoType>();
1383 auto AI = FPT->param_type_begin(), AE = FPT->param_type_end();
1384
1385 // The first argument is always a void*.
1386 ++AI;
1387
1388 // The next parameter may be a std::destroying_delete_t.
1389 if (FD->isDestroyingOperatorDelete()) {
1390 Params.DestroyingDelete = true;
1391 assert(AI != AE);
1392 ++AI;
1393 }
1394
1395 // Figure out what other parameters we should be implicitly passing.
1396 if (AI != AE && (*AI)->isIntegerType()) {
1397 Params.Size = true;
1398 ++AI;
1399 }
1400
1401 if (AI != AE && (*AI)->isAlignValT()) {
1402 Params.Alignment = true;
1403 ++AI;
1404 }
1405
1406 assert(AI == AE && "unexpected usual deallocation function parameter");
1407 return Params;
1408 }
1409
1410 namespace {
1411 /// A cleanup to call the given 'operator delete' function upon abnormal
1412 /// exit from a new expression. Templated on a traits type that deals with
1413 /// ensuring that the arguments dominate the cleanup if necessary.
1414 template<typename Traits>
1415 class CallDeleteDuringNew final : public EHScopeStack::Cleanup {
1416 /// Type used to hold llvm::Value*s.
1417 typedef typename Traits::ValueTy ValueTy;
1418 /// Type used to hold RValues.
1419 typedef typename Traits::RValueTy RValueTy;
1420 struct PlacementArg {
1421 RValueTy ArgValue;
1422 QualType ArgType;
1423 };
1424
1425 unsigned NumPlacementArgs : 31;
1426 unsigned PassAlignmentToPlacementDelete : 1;
1427 const FunctionDecl *OperatorDelete;
1428 ValueTy Ptr;
1429 ValueTy AllocSize;
1430 CharUnits AllocAlign;
1431
getPlacementArgs()1432 PlacementArg *getPlacementArgs() {
1433 return reinterpret_cast<PlacementArg *>(this + 1);
1434 }
1435
1436 public:
getExtraSize(size_t NumPlacementArgs)1437 static size_t getExtraSize(size_t NumPlacementArgs) {
1438 return NumPlacementArgs * sizeof(PlacementArg);
1439 }
1440
CallDeleteDuringNew(size_t NumPlacementArgs,const FunctionDecl * OperatorDelete,ValueTy Ptr,ValueTy AllocSize,bool PassAlignmentToPlacementDelete,CharUnits AllocAlign)1441 CallDeleteDuringNew(size_t NumPlacementArgs,
1442 const FunctionDecl *OperatorDelete, ValueTy Ptr,
1443 ValueTy AllocSize, bool PassAlignmentToPlacementDelete,
1444 CharUnits AllocAlign)
1445 : NumPlacementArgs(NumPlacementArgs),
1446 PassAlignmentToPlacementDelete(PassAlignmentToPlacementDelete),
1447 OperatorDelete(OperatorDelete), Ptr(Ptr), AllocSize(AllocSize),
1448 AllocAlign(AllocAlign) {}
1449
setPlacementArg(unsigned I,RValueTy Arg,QualType Type)1450 void setPlacementArg(unsigned I, RValueTy Arg, QualType Type) {
1451 assert(I < NumPlacementArgs && "index out of range");
1452 getPlacementArgs()[I] = {Arg, Type};
1453 }
1454
Emit(CodeGenFunction & CGF,Flags flags)1455 void Emit(CodeGenFunction &CGF, Flags flags) override {
1456 const auto *FPT = OperatorDelete->getType()->castAs<FunctionProtoType>();
1457 CallArgList DeleteArgs;
1458
1459 // The first argument is always a void* (or C* for a destroying operator
1460 // delete for class type C).
1461 DeleteArgs.add(Traits::get(CGF, Ptr), FPT->getParamType(0));
1462
1463 // Figure out what other parameters we should be implicitly passing.
1464 UsualDeleteParams Params;
1465 if (NumPlacementArgs) {
1466 // A placement deallocation function is implicitly passed an alignment
1467 // if the placement allocation function was, but is never passed a size.
1468 Params.Alignment = PassAlignmentToPlacementDelete;
1469 } else {
1470 // For a non-placement new-expression, 'operator delete' can take a
1471 // size and/or an alignment if it has the right parameters.
1472 Params = getUsualDeleteParams(OperatorDelete);
1473 }
1474
1475 assert(!Params.DestroyingDelete &&
1476 "should not call destroying delete in a new-expression");
1477
1478 // The second argument can be a std::size_t (for non-placement delete).
1479 if (Params.Size)
1480 DeleteArgs.add(Traits::get(CGF, AllocSize),
1481 CGF.getContext().getSizeType());
1482
1483 // The next (second or third) argument can be a std::align_val_t, which
1484 // is an enum whose underlying type is std::size_t.
1485 // FIXME: Use the right type as the parameter type. Note that in a call
1486 // to operator delete(size_t, ...), we may not have it available.
1487 if (Params.Alignment)
1488 DeleteArgs.add(RValue::get(llvm::ConstantInt::get(
1489 CGF.SizeTy, AllocAlign.getQuantity())),
1490 CGF.getContext().getSizeType());
1491
1492 // Pass the rest of the arguments, which must match exactly.
1493 for (unsigned I = 0; I != NumPlacementArgs; ++I) {
1494 auto Arg = getPlacementArgs()[I];
1495 DeleteArgs.add(Traits::get(CGF, Arg.ArgValue), Arg.ArgType);
1496 }
1497
1498 // Call 'operator delete'.
1499 EmitNewDeleteCall(CGF, OperatorDelete, FPT, DeleteArgs);
1500 }
1501 };
1502 }
1503
1504 /// Enter a cleanup to call 'operator delete' if the initializer in a
1505 /// new-expression throws.
EnterNewDeleteCleanup(CodeGenFunction & CGF,const CXXNewExpr * E,Address NewPtr,llvm::Value * AllocSize,CharUnits AllocAlign,const CallArgList & NewArgs)1506 static void EnterNewDeleteCleanup(CodeGenFunction &CGF,
1507 const CXXNewExpr *E,
1508 Address NewPtr,
1509 llvm::Value *AllocSize,
1510 CharUnits AllocAlign,
1511 const CallArgList &NewArgs) {
1512 unsigned NumNonPlacementArgs = E->passAlignment() ? 2 : 1;
1513
1514 // If we're not inside a conditional branch, then the cleanup will
1515 // dominate and we can do the easier (and more efficient) thing.
1516 if (!CGF.isInConditionalBranch()) {
1517 struct DirectCleanupTraits {
1518 typedef llvm::Value *ValueTy;
1519 typedef RValue RValueTy;
1520 static RValue get(CodeGenFunction &, ValueTy V) { return RValue::get(V); }
1521 static RValue get(CodeGenFunction &, RValueTy V) { return V; }
1522 };
1523
1524 typedef CallDeleteDuringNew<DirectCleanupTraits> DirectCleanup;
1525
1526 DirectCleanup *Cleanup = CGF.EHStack
1527 .pushCleanupWithExtra<DirectCleanup>(EHCleanup,
1528 E->getNumPlacementArgs(),
1529 E->getOperatorDelete(),
1530 NewPtr.getPointer(),
1531 AllocSize,
1532 E->passAlignment(),
1533 AllocAlign);
1534 for (unsigned I = 0, N = E->getNumPlacementArgs(); I != N; ++I) {
1535 auto &Arg = NewArgs[I + NumNonPlacementArgs];
1536 Cleanup->setPlacementArg(I, Arg.getRValue(CGF), Arg.Ty);
1537 }
1538
1539 return;
1540 }
1541
1542 // Otherwise, we need to save all this stuff.
1543 DominatingValue<RValue>::saved_type SavedNewPtr =
1544 DominatingValue<RValue>::save(CGF, RValue::get(NewPtr.getPointer()));
1545 DominatingValue<RValue>::saved_type SavedAllocSize =
1546 DominatingValue<RValue>::save(CGF, RValue::get(AllocSize));
1547
1548 struct ConditionalCleanupTraits {
1549 typedef DominatingValue<RValue>::saved_type ValueTy;
1550 typedef DominatingValue<RValue>::saved_type RValueTy;
1551 static RValue get(CodeGenFunction &CGF, ValueTy V) {
1552 return V.restore(CGF);
1553 }
1554 };
1555 typedef CallDeleteDuringNew<ConditionalCleanupTraits> ConditionalCleanup;
1556
1557 ConditionalCleanup *Cleanup = CGF.EHStack
1558 .pushCleanupWithExtra<ConditionalCleanup>(EHCleanup,
1559 E->getNumPlacementArgs(),
1560 E->getOperatorDelete(),
1561 SavedNewPtr,
1562 SavedAllocSize,
1563 E->passAlignment(),
1564 AllocAlign);
1565 for (unsigned I = 0, N = E->getNumPlacementArgs(); I != N; ++I) {
1566 auto &Arg = NewArgs[I + NumNonPlacementArgs];
1567 Cleanup->setPlacementArg(
1568 I, DominatingValue<RValue>::save(CGF, Arg.getRValue(CGF)), Arg.Ty);
1569 }
1570
1571 CGF.initFullExprCleanup();
1572 }
1573
EmitCXXNewExpr(const CXXNewExpr * E)1574 llvm::Value *CodeGenFunction::EmitCXXNewExpr(const CXXNewExpr *E) {
1575 // The element type being allocated.
1576 QualType allocType = getContext().getBaseElementType(E->getAllocatedType());
1577
1578 // 1. Build a call to the allocation function.
1579 FunctionDecl *allocator = E->getOperatorNew();
1580
1581 // If there is a brace-initializer or C++20 parenthesized initializer, cannot
1582 // allocate fewer elements than inits.
1583 unsigned minElements = 0;
1584 if (E->isArray() && E->hasInitializer()) {
1585 const Expr *Init = E->getInitializer();
1586 const InitListExpr *ILE = dyn_cast<InitListExpr>(Init);
1587 const CXXParenListInitExpr *CPLIE = dyn_cast<CXXParenListInitExpr>(Init);
1588 const Expr *IgnoreParen = Init->IgnoreParenImpCasts();
1589 if ((ILE && ILE->isStringLiteralInit()) ||
1590 isa<StringLiteral>(IgnoreParen) || isa<ObjCEncodeExpr>(IgnoreParen)) {
1591 minElements =
1592 cast<ConstantArrayType>(Init->getType()->getAsArrayTypeUnsafe())
1593 ->getSize()
1594 .getZExtValue();
1595 } else if (ILE || CPLIE) {
1596 minElements = ILE ? ILE->getNumInits() : CPLIE->getInitExprs().size();
1597 }
1598 }
1599
1600 llvm::Value *numElements = nullptr;
1601 llvm::Value *allocSizeWithoutCookie = nullptr;
1602 llvm::Value *allocSize =
1603 EmitCXXNewAllocSize(*this, E, minElements, numElements,
1604 allocSizeWithoutCookie);
1605 CharUnits allocAlign = getContext().getTypeAlignInChars(allocType);
1606
1607 // Emit the allocation call. If the allocator is a global placement
1608 // operator, just "inline" it directly.
1609 Address allocation = Address::invalid();
1610 CallArgList allocatorArgs;
1611 if (allocator->isReservedGlobalPlacementOperator()) {
1612 assert(E->getNumPlacementArgs() == 1);
1613 const Expr *arg = *E->placement_arguments().begin();
1614
1615 LValueBaseInfo BaseInfo;
1616 allocation = EmitPointerWithAlignment(arg, &BaseInfo);
1617
1618 // The pointer expression will, in many cases, be an opaque void*.
1619 // In these cases, discard the computed alignment and use the
1620 // formal alignment of the allocated type.
1621 if (BaseInfo.getAlignmentSource() != AlignmentSource::Decl)
1622 allocation = allocation.withAlignment(allocAlign);
1623
1624 // Set up allocatorArgs for the call to operator delete if it's not
1625 // the reserved global operator.
1626 if (E->getOperatorDelete() &&
1627 !E->getOperatorDelete()->isReservedGlobalPlacementOperator()) {
1628 allocatorArgs.add(RValue::get(allocSize), getContext().getSizeType());
1629 allocatorArgs.add(RValue::get(allocation.getPointer()), arg->getType());
1630 }
1631
1632 } else {
1633 const FunctionProtoType *allocatorType =
1634 allocator->getType()->castAs<FunctionProtoType>();
1635 unsigned ParamsToSkip = 0;
1636
1637 // The allocation size is the first argument.
1638 QualType sizeType = getContext().getSizeType();
1639 allocatorArgs.add(RValue::get(allocSize), sizeType);
1640 ++ParamsToSkip;
1641
1642 if (allocSize != allocSizeWithoutCookie) {
1643 CharUnits cookieAlign = getSizeAlign(); // FIXME: Ask the ABI.
1644 allocAlign = std::max(allocAlign, cookieAlign);
1645 }
1646
1647 // The allocation alignment may be passed as the second argument.
1648 if (E->passAlignment()) {
1649 QualType AlignValT = sizeType;
1650 if (allocatorType->getNumParams() > 1) {
1651 AlignValT = allocatorType->getParamType(1);
1652 assert(getContext().hasSameUnqualifiedType(
1653 AlignValT->castAs<EnumType>()->getDecl()->getIntegerType(),
1654 sizeType) &&
1655 "wrong type for alignment parameter");
1656 ++ParamsToSkip;
1657 } else {
1658 // Corner case, passing alignment to 'operator new(size_t, ...)'.
1659 assert(allocator->isVariadic() && "can't pass alignment to allocator");
1660 }
1661 allocatorArgs.add(
1662 RValue::get(llvm::ConstantInt::get(SizeTy, allocAlign.getQuantity())),
1663 AlignValT);
1664 }
1665
1666 // FIXME: Why do we not pass a CalleeDecl here?
1667 EmitCallArgs(allocatorArgs, allocatorType, E->placement_arguments(),
1668 /*AC*/AbstractCallee(), /*ParamsToSkip*/ParamsToSkip);
1669
1670 RValue RV =
1671 EmitNewDeleteCall(*this, allocator, allocatorType, allocatorArgs);
1672
1673 // Set !heapallocsite metadata on the call to operator new.
1674 if (getDebugInfo())
1675 if (auto *newCall = dyn_cast<llvm::CallBase>(RV.getScalarVal()))
1676 getDebugInfo()->addHeapAllocSiteMetadata(newCall, allocType,
1677 E->getExprLoc());
1678
1679 // If this was a call to a global replaceable allocation function that does
1680 // not take an alignment argument, the allocator is known to produce
1681 // storage that's suitably aligned for any object that fits, up to a known
1682 // threshold. Otherwise assume it's suitably aligned for the allocated type.
1683 CharUnits allocationAlign = allocAlign;
1684 if (!E->passAlignment() &&
1685 allocator->isReplaceableGlobalAllocationFunction()) {
1686 unsigned AllocatorAlign = llvm::bit_floor(std::min<uint64_t>(
1687 Target.getNewAlign(), getContext().getTypeSize(allocType)));
1688 allocationAlign = std::max(
1689 allocationAlign, getContext().toCharUnitsFromBits(AllocatorAlign));
1690 }
1691
1692 allocation = Address(RV.getScalarVal(), Int8Ty, allocationAlign);
1693 }
1694
1695 // Emit a null check on the allocation result if the allocation
1696 // function is allowed to return null (because it has a non-throwing
1697 // exception spec or is the reserved placement new) and we have an
1698 // interesting initializer will be running sanitizers on the initialization.
1699 bool nullCheck = E->shouldNullCheckAllocation() &&
1700 (!allocType.isPODType(getContext()) || E->hasInitializer() ||
1701 sanitizePerformTypeCheck());
1702
1703 llvm::BasicBlock *nullCheckBB = nullptr;
1704 llvm::BasicBlock *contBB = nullptr;
1705
1706 // The null-check means that the initializer is conditionally
1707 // evaluated.
1708 ConditionalEvaluation conditional(*this);
1709
1710 if (nullCheck) {
1711 conditional.begin(*this);
1712
1713 nullCheckBB = Builder.GetInsertBlock();
1714 llvm::BasicBlock *notNullBB = createBasicBlock("new.notnull");
1715 contBB = createBasicBlock("new.cont");
1716
1717 llvm::Value *isNull =
1718 Builder.CreateIsNull(allocation.getPointer(), "new.isnull");
1719 Builder.CreateCondBr(isNull, contBB, notNullBB);
1720 EmitBlock(notNullBB);
1721 }
1722
1723 // If there's an operator delete, enter a cleanup to call it if an
1724 // exception is thrown.
1725 EHScopeStack::stable_iterator operatorDeleteCleanup;
1726 llvm::Instruction *cleanupDominator = nullptr;
1727 if (E->getOperatorDelete() &&
1728 !E->getOperatorDelete()->isReservedGlobalPlacementOperator()) {
1729 EnterNewDeleteCleanup(*this, E, allocation, allocSize, allocAlign,
1730 allocatorArgs);
1731 operatorDeleteCleanup = EHStack.stable_begin();
1732 cleanupDominator = Builder.CreateUnreachable();
1733 }
1734
1735 assert((allocSize == allocSizeWithoutCookie) ==
1736 CalculateCookiePadding(*this, E).isZero());
1737 if (allocSize != allocSizeWithoutCookie) {
1738 assert(E->isArray());
1739 allocation = CGM.getCXXABI().InitializeArrayCookie(*this, allocation,
1740 numElements,
1741 E, allocType);
1742 }
1743
1744 llvm::Type *elementTy = ConvertTypeForMem(allocType);
1745 Address result = allocation.withElementType(elementTy);
1746
1747 // Passing pointer through launder.invariant.group to avoid propagation of
1748 // vptrs information which may be included in previous type.
1749 // To not break LTO with different optimizations levels, we do it regardless
1750 // of optimization level.
1751 if (CGM.getCodeGenOpts().StrictVTablePointers &&
1752 allocator->isReservedGlobalPlacementOperator())
1753 result = Builder.CreateLaunderInvariantGroup(result);
1754
1755 // Emit sanitizer checks for pointer value now, so that in the case of an
1756 // array it was checked only once and not at each constructor call. We may
1757 // have already checked that the pointer is non-null.
1758 // FIXME: If we have an array cookie and a potentially-throwing allocator,
1759 // we'll null check the wrong pointer here.
1760 SanitizerSet SkippedChecks;
1761 SkippedChecks.set(SanitizerKind::Null, nullCheck);
1762 EmitTypeCheck(CodeGenFunction::TCK_ConstructorCall,
1763 E->getAllocatedTypeSourceInfo()->getTypeLoc().getBeginLoc(),
1764 result.getPointer(), allocType, result.getAlignment(),
1765 SkippedChecks, numElements);
1766
1767 EmitNewInitializer(*this, E, allocType, elementTy, result, numElements,
1768 allocSizeWithoutCookie);
1769 llvm::Value *resultPtr = result.getPointer();
1770 if (E->isArray()) {
1771 // NewPtr is a pointer to the base element type. If we're
1772 // allocating an array of arrays, we'll need to cast back to the
1773 // array pointer type.
1774 llvm::Type *resultType = ConvertTypeForMem(E->getType());
1775 if (resultPtr->getType() != resultType)
1776 resultPtr = Builder.CreateBitCast(resultPtr, resultType);
1777 }
1778
1779 // Deactivate the 'operator delete' cleanup if we finished
1780 // initialization.
1781 if (operatorDeleteCleanup.isValid()) {
1782 DeactivateCleanupBlock(operatorDeleteCleanup, cleanupDominator);
1783 cleanupDominator->eraseFromParent();
1784 }
1785
1786 if (nullCheck) {
1787 conditional.end(*this);
1788
1789 llvm::BasicBlock *notNullBB = Builder.GetInsertBlock();
1790 EmitBlock(contBB);
1791
1792 llvm::PHINode *PHI = Builder.CreatePHI(resultPtr->getType(), 2);
1793 PHI->addIncoming(resultPtr, notNullBB);
1794 PHI->addIncoming(llvm::Constant::getNullValue(resultPtr->getType()),
1795 nullCheckBB);
1796
1797 resultPtr = PHI;
1798 }
1799
1800 return resultPtr;
1801 }
1802
EmitDeleteCall(const FunctionDecl * DeleteFD,llvm::Value * Ptr,QualType DeleteTy,llvm::Value * NumElements,CharUnits CookieSize)1803 void CodeGenFunction::EmitDeleteCall(const FunctionDecl *DeleteFD,
1804 llvm::Value *Ptr, QualType DeleteTy,
1805 llvm::Value *NumElements,
1806 CharUnits CookieSize) {
1807 assert((!NumElements && CookieSize.isZero()) ||
1808 DeleteFD->getOverloadedOperator() == OO_Array_Delete);
1809
1810 const auto *DeleteFTy = DeleteFD->getType()->castAs<FunctionProtoType>();
1811 CallArgList DeleteArgs;
1812
1813 auto Params = getUsualDeleteParams(DeleteFD);
1814 auto ParamTypeIt = DeleteFTy->param_type_begin();
1815
1816 // Pass the pointer itself.
1817 QualType ArgTy = *ParamTypeIt++;
1818 llvm::Value *DeletePtr = Builder.CreateBitCast(Ptr, ConvertType(ArgTy));
1819 DeleteArgs.add(RValue::get(DeletePtr), ArgTy);
1820
1821 // Pass the std::destroying_delete tag if present.
1822 llvm::AllocaInst *DestroyingDeleteTag = nullptr;
1823 if (Params.DestroyingDelete) {
1824 QualType DDTag = *ParamTypeIt++;
1825 llvm::Type *Ty = getTypes().ConvertType(DDTag);
1826 CharUnits Align = CGM.getNaturalTypeAlignment(DDTag);
1827 DestroyingDeleteTag = CreateTempAlloca(Ty, "destroying.delete.tag");
1828 DestroyingDeleteTag->setAlignment(Align.getAsAlign());
1829 DeleteArgs.add(
1830 RValue::getAggregate(Address(DestroyingDeleteTag, Ty, Align)), DDTag);
1831 }
1832
1833 // Pass the size if the delete function has a size_t parameter.
1834 if (Params.Size) {
1835 QualType SizeType = *ParamTypeIt++;
1836 CharUnits DeleteTypeSize = getContext().getTypeSizeInChars(DeleteTy);
1837 llvm::Value *Size = llvm::ConstantInt::get(ConvertType(SizeType),
1838 DeleteTypeSize.getQuantity());
1839
1840 // For array new, multiply by the number of elements.
1841 if (NumElements)
1842 Size = Builder.CreateMul(Size, NumElements);
1843
1844 // If there is a cookie, add the cookie size.
1845 if (!CookieSize.isZero())
1846 Size = Builder.CreateAdd(
1847 Size, llvm::ConstantInt::get(SizeTy, CookieSize.getQuantity()));
1848
1849 DeleteArgs.add(RValue::get(Size), SizeType);
1850 }
1851
1852 // Pass the alignment if the delete function has an align_val_t parameter.
1853 if (Params.Alignment) {
1854 QualType AlignValType = *ParamTypeIt++;
1855 CharUnits DeleteTypeAlign =
1856 getContext().toCharUnitsFromBits(getContext().getTypeAlignIfKnown(
1857 DeleteTy, true /* NeedsPreferredAlignment */));
1858 llvm::Value *Align = llvm::ConstantInt::get(ConvertType(AlignValType),
1859 DeleteTypeAlign.getQuantity());
1860 DeleteArgs.add(RValue::get(Align), AlignValType);
1861 }
1862
1863 assert(ParamTypeIt == DeleteFTy->param_type_end() &&
1864 "unknown parameter to usual delete function");
1865
1866 // Emit the call to delete.
1867 EmitNewDeleteCall(*this, DeleteFD, DeleteFTy, DeleteArgs);
1868
1869 // If call argument lowering didn't use the destroying_delete_t alloca,
1870 // remove it again.
1871 if (DestroyingDeleteTag && DestroyingDeleteTag->use_empty())
1872 DestroyingDeleteTag->eraseFromParent();
1873 }
1874
1875 namespace {
1876 /// Calls the given 'operator delete' on a single object.
1877 struct CallObjectDelete final : EHScopeStack::Cleanup {
1878 llvm::Value *Ptr;
1879 const FunctionDecl *OperatorDelete;
1880 QualType ElementType;
1881
CallObjectDelete__anon1726de420511::CallObjectDelete1882 CallObjectDelete(llvm::Value *Ptr,
1883 const FunctionDecl *OperatorDelete,
1884 QualType ElementType)
1885 : Ptr(Ptr), OperatorDelete(OperatorDelete), ElementType(ElementType) {}
1886
Emit__anon1726de420511::CallObjectDelete1887 void Emit(CodeGenFunction &CGF, Flags flags) override {
1888 CGF.EmitDeleteCall(OperatorDelete, Ptr, ElementType);
1889 }
1890 };
1891 }
1892
1893 void
pushCallObjectDeleteCleanup(const FunctionDecl * OperatorDelete,llvm::Value * CompletePtr,QualType ElementType)1894 CodeGenFunction::pushCallObjectDeleteCleanup(const FunctionDecl *OperatorDelete,
1895 llvm::Value *CompletePtr,
1896 QualType ElementType) {
1897 EHStack.pushCleanup<CallObjectDelete>(NormalAndEHCleanup, CompletePtr,
1898 OperatorDelete, ElementType);
1899 }
1900
1901 /// Emit the code for deleting a single object with a destroying operator
1902 /// delete. If the element type has a non-virtual destructor, Ptr has already
1903 /// been converted to the type of the parameter of 'operator delete'. Otherwise
1904 /// Ptr points to an object of the static type.
EmitDestroyingObjectDelete(CodeGenFunction & CGF,const CXXDeleteExpr * DE,Address Ptr,QualType ElementType)1905 static void EmitDestroyingObjectDelete(CodeGenFunction &CGF,
1906 const CXXDeleteExpr *DE, Address Ptr,
1907 QualType ElementType) {
1908 auto *Dtor = ElementType->getAsCXXRecordDecl()->getDestructor();
1909 if (Dtor && Dtor->isVirtual())
1910 CGF.CGM.getCXXABI().emitVirtualObjectDelete(CGF, DE, Ptr, ElementType,
1911 Dtor);
1912 else
1913 CGF.EmitDeleteCall(DE->getOperatorDelete(), Ptr.getPointer(), ElementType);
1914 }
1915
1916 /// Emit the code for deleting a single object.
1917 /// \return \c true if we started emitting UnconditionalDeleteBlock, \c false
1918 /// if not.
EmitObjectDelete(CodeGenFunction & CGF,const CXXDeleteExpr * DE,Address Ptr,QualType ElementType,llvm::BasicBlock * UnconditionalDeleteBlock)1919 static bool EmitObjectDelete(CodeGenFunction &CGF,
1920 const CXXDeleteExpr *DE,
1921 Address Ptr,
1922 QualType ElementType,
1923 llvm::BasicBlock *UnconditionalDeleteBlock) {
1924 // C++11 [expr.delete]p3:
1925 // If the static type of the object to be deleted is different from its
1926 // dynamic type, the static type shall be a base class of the dynamic type
1927 // of the object to be deleted and the static type shall have a virtual
1928 // destructor or the behavior is undefined.
1929 CGF.EmitTypeCheck(CodeGenFunction::TCK_MemberCall,
1930 DE->getExprLoc(), Ptr.getPointer(),
1931 ElementType);
1932
1933 const FunctionDecl *OperatorDelete = DE->getOperatorDelete();
1934 assert(!OperatorDelete->isDestroyingOperatorDelete());
1935
1936 // Find the destructor for the type, if applicable. If the
1937 // destructor is virtual, we'll just emit the vcall and return.
1938 const CXXDestructorDecl *Dtor = nullptr;
1939 if (const RecordType *RT = ElementType->getAs<RecordType>()) {
1940 CXXRecordDecl *RD = cast<CXXRecordDecl>(RT->getDecl());
1941 if (RD->hasDefinition() && !RD->hasTrivialDestructor()) {
1942 Dtor = RD->getDestructor();
1943
1944 if (Dtor->isVirtual()) {
1945 bool UseVirtualCall = true;
1946 const Expr *Base = DE->getArgument();
1947 if (auto *DevirtualizedDtor =
1948 dyn_cast_or_null<const CXXDestructorDecl>(
1949 Dtor->getDevirtualizedMethod(
1950 Base, CGF.CGM.getLangOpts().AppleKext))) {
1951 UseVirtualCall = false;
1952 const CXXRecordDecl *DevirtualizedClass =
1953 DevirtualizedDtor->getParent();
1954 if (declaresSameEntity(getCXXRecord(Base), DevirtualizedClass)) {
1955 // Devirtualized to the class of the base type (the type of the
1956 // whole expression).
1957 Dtor = DevirtualizedDtor;
1958 } else {
1959 // Devirtualized to some other type. Would need to cast the this
1960 // pointer to that type but we don't have support for that yet, so
1961 // do a virtual call. FIXME: handle the case where it is
1962 // devirtualized to the derived type (the type of the inner
1963 // expression) as in EmitCXXMemberOrOperatorMemberCallExpr.
1964 UseVirtualCall = true;
1965 }
1966 }
1967 if (UseVirtualCall) {
1968 CGF.CGM.getCXXABI().emitVirtualObjectDelete(CGF, DE, Ptr, ElementType,
1969 Dtor);
1970 return false;
1971 }
1972 }
1973 }
1974 }
1975
1976 // Make sure that we call delete even if the dtor throws.
1977 // This doesn't have to a conditional cleanup because we're going
1978 // to pop it off in a second.
1979 CGF.EHStack.pushCleanup<CallObjectDelete>(NormalAndEHCleanup,
1980 Ptr.getPointer(),
1981 OperatorDelete, ElementType);
1982
1983 if (Dtor)
1984 CGF.EmitCXXDestructorCall(Dtor, Dtor_Complete,
1985 /*ForVirtualBase=*/false,
1986 /*Delegating=*/false,
1987 Ptr, ElementType);
1988 else if (auto Lifetime = ElementType.getObjCLifetime()) {
1989 switch (Lifetime) {
1990 case Qualifiers::OCL_None:
1991 case Qualifiers::OCL_ExplicitNone:
1992 case Qualifiers::OCL_Autoreleasing:
1993 break;
1994
1995 case Qualifiers::OCL_Strong:
1996 CGF.EmitARCDestroyStrong(Ptr, ARCPreciseLifetime);
1997 break;
1998
1999 case Qualifiers::OCL_Weak:
2000 CGF.EmitARCDestroyWeak(Ptr);
2001 break;
2002 }
2003 }
2004
2005 // When optimizing for size, call 'operator delete' unconditionally.
2006 if (CGF.CGM.getCodeGenOpts().OptimizeSize > 1) {
2007 CGF.EmitBlock(UnconditionalDeleteBlock);
2008 CGF.PopCleanupBlock();
2009 return true;
2010 }
2011
2012 CGF.PopCleanupBlock();
2013 return false;
2014 }
2015
2016 namespace {
2017 /// Calls the given 'operator delete' on an array of objects.
2018 struct CallArrayDelete final : EHScopeStack::Cleanup {
2019 llvm::Value *Ptr;
2020 const FunctionDecl *OperatorDelete;
2021 llvm::Value *NumElements;
2022 QualType ElementType;
2023 CharUnits CookieSize;
2024
CallArrayDelete__anon1726de420611::CallArrayDelete2025 CallArrayDelete(llvm::Value *Ptr,
2026 const FunctionDecl *OperatorDelete,
2027 llvm::Value *NumElements,
2028 QualType ElementType,
2029 CharUnits CookieSize)
2030 : Ptr(Ptr), OperatorDelete(OperatorDelete), NumElements(NumElements),
2031 ElementType(ElementType), CookieSize(CookieSize) {}
2032
Emit__anon1726de420611::CallArrayDelete2033 void Emit(CodeGenFunction &CGF, Flags flags) override {
2034 CGF.EmitDeleteCall(OperatorDelete, Ptr, ElementType, NumElements,
2035 CookieSize);
2036 }
2037 };
2038 }
2039
2040 /// Emit the code for deleting an array of objects.
EmitArrayDelete(CodeGenFunction & CGF,const CXXDeleteExpr * E,Address deletedPtr,QualType elementType)2041 static void EmitArrayDelete(CodeGenFunction &CGF,
2042 const CXXDeleteExpr *E,
2043 Address deletedPtr,
2044 QualType elementType) {
2045 llvm::Value *numElements = nullptr;
2046 llvm::Value *allocatedPtr = nullptr;
2047 CharUnits cookieSize;
2048 CGF.CGM.getCXXABI().ReadArrayCookie(CGF, deletedPtr, E, elementType,
2049 numElements, allocatedPtr, cookieSize);
2050
2051 assert(allocatedPtr && "ReadArrayCookie didn't set allocated pointer");
2052
2053 // Make sure that we call delete even if one of the dtors throws.
2054 const FunctionDecl *operatorDelete = E->getOperatorDelete();
2055 CGF.EHStack.pushCleanup<CallArrayDelete>(NormalAndEHCleanup,
2056 allocatedPtr, operatorDelete,
2057 numElements, elementType,
2058 cookieSize);
2059
2060 // Destroy the elements.
2061 if (QualType::DestructionKind dtorKind = elementType.isDestructedType()) {
2062 assert(numElements && "no element count for a type with a destructor!");
2063
2064 CharUnits elementSize = CGF.getContext().getTypeSizeInChars(elementType);
2065 CharUnits elementAlign =
2066 deletedPtr.getAlignment().alignmentOfArrayElement(elementSize);
2067
2068 llvm::Value *arrayBegin = deletedPtr.getPointer();
2069 llvm::Value *arrayEnd = CGF.Builder.CreateInBoundsGEP(
2070 deletedPtr.getElementType(), arrayBegin, numElements, "delete.end");
2071
2072 // Note that it is legal to allocate a zero-length array, and we
2073 // can never fold the check away because the length should always
2074 // come from a cookie.
2075 CGF.emitArrayDestroy(arrayBegin, arrayEnd, elementType, elementAlign,
2076 CGF.getDestroyer(dtorKind),
2077 /*checkZeroLength*/ true,
2078 CGF.needsEHCleanup(dtorKind));
2079 }
2080
2081 // Pop the cleanup block.
2082 CGF.PopCleanupBlock();
2083 }
2084
EmitCXXDeleteExpr(const CXXDeleteExpr * E)2085 void CodeGenFunction::EmitCXXDeleteExpr(const CXXDeleteExpr *E) {
2086 const Expr *Arg = E->getArgument();
2087 Address Ptr = EmitPointerWithAlignment(Arg);
2088
2089 // Null check the pointer.
2090 //
2091 // We could avoid this null check if we can determine that the object
2092 // destruction is trivial and doesn't require an array cookie; we can
2093 // unconditionally perform the operator delete call in that case. For now, we
2094 // assume that deleted pointers are null rarely enough that it's better to
2095 // keep the branch. This might be worth revisiting for a -O0 code size win.
2096 llvm::BasicBlock *DeleteNotNull = createBasicBlock("delete.notnull");
2097 llvm::BasicBlock *DeleteEnd = createBasicBlock("delete.end");
2098
2099 llvm::Value *IsNull = Builder.CreateIsNull(Ptr.getPointer(), "isnull");
2100
2101 Builder.CreateCondBr(IsNull, DeleteEnd, DeleteNotNull);
2102 EmitBlock(DeleteNotNull);
2103 Ptr.setKnownNonNull();
2104
2105 QualType DeleteTy = E->getDestroyedType();
2106
2107 // A destroying operator delete overrides the entire operation of the
2108 // delete expression.
2109 if (E->getOperatorDelete()->isDestroyingOperatorDelete()) {
2110 EmitDestroyingObjectDelete(*this, E, Ptr, DeleteTy);
2111 EmitBlock(DeleteEnd);
2112 return;
2113 }
2114
2115 // We might be deleting a pointer to array. If so, GEP down to the
2116 // first non-array element.
2117 // (this assumes that A(*)[3][7] is converted to [3 x [7 x %A]]*)
2118 if (DeleteTy->isConstantArrayType()) {
2119 llvm::Value *Zero = Builder.getInt32(0);
2120 SmallVector<llvm::Value*,8> GEP;
2121
2122 GEP.push_back(Zero); // point at the outermost array
2123
2124 // For each layer of array type we're pointing at:
2125 while (const ConstantArrayType *Arr
2126 = getContext().getAsConstantArrayType(DeleteTy)) {
2127 // 1. Unpeel the array type.
2128 DeleteTy = Arr->getElementType();
2129
2130 // 2. GEP to the first element of the array.
2131 GEP.push_back(Zero);
2132 }
2133
2134 Ptr = Address(Builder.CreateInBoundsGEP(Ptr.getElementType(),
2135 Ptr.getPointer(), GEP, "del.first"),
2136 ConvertTypeForMem(DeleteTy), Ptr.getAlignment(),
2137 Ptr.isKnownNonNull());
2138 }
2139
2140 assert(ConvertTypeForMem(DeleteTy) == Ptr.getElementType());
2141
2142 if (E->isArrayForm()) {
2143 EmitArrayDelete(*this, E, Ptr, DeleteTy);
2144 EmitBlock(DeleteEnd);
2145 } else {
2146 if (!EmitObjectDelete(*this, E, Ptr, DeleteTy, DeleteEnd))
2147 EmitBlock(DeleteEnd);
2148 }
2149 }
2150
isGLValueFromPointerDeref(const Expr * E)2151 static bool isGLValueFromPointerDeref(const Expr *E) {
2152 E = E->IgnoreParens();
2153
2154 if (const auto *CE = dyn_cast<CastExpr>(E)) {
2155 if (!CE->getSubExpr()->isGLValue())
2156 return false;
2157 return isGLValueFromPointerDeref(CE->getSubExpr());
2158 }
2159
2160 if (const auto *OVE = dyn_cast<OpaqueValueExpr>(E))
2161 return isGLValueFromPointerDeref(OVE->getSourceExpr());
2162
2163 if (const auto *BO = dyn_cast<BinaryOperator>(E))
2164 if (BO->getOpcode() == BO_Comma)
2165 return isGLValueFromPointerDeref(BO->getRHS());
2166
2167 if (const auto *ACO = dyn_cast<AbstractConditionalOperator>(E))
2168 return isGLValueFromPointerDeref(ACO->getTrueExpr()) ||
2169 isGLValueFromPointerDeref(ACO->getFalseExpr());
2170
2171 // C++11 [expr.sub]p1:
2172 // The expression E1[E2] is identical (by definition) to *((E1)+(E2))
2173 if (isa<ArraySubscriptExpr>(E))
2174 return true;
2175
2176 if (const auto *UO = dyn_cast<UnaryOperator>(E))
2177 if (UO->getOpcode() == UO_Deref)
2178 return true;
2179
2180 return false;
2181 }
2182
EmitTypeidFromVTable(CodeGenFunction & CGF,const Expr * E,llvm::Type * StdTypeInfoPtrTy)2183 static llvm::Value *EmitTypeidFromVTable(CodeGenFunction &CGF, const Expr *E,
2184 llvm::Type *StdTypeInfoPtrTy) {
2185 // Get the vtable pointer.
2186 Address ThisPtr = CGF.EmitLValue(E).getAddress(CGF);
2187
2188 QualType SrcRecordTy = E->getType();
2189
2190 // C++ [class.cdtor]p4:
2191 // If the operand of typeid refers to the object under construction or
2192 // destruction and the static type of the operand is neither the constructor
2193 // or destructor’s class nor one of its bases, the behavior is undefined.
2194 CGF.EmitTypeCheck(CodeGenFunction::TCK_DynamicOperation, E->getExprLoc(),
2195 ThisPtr.getPointer(), SrcRecordTy);
2196
2197 // C++ [expr.typeid]p2:
2198 // If the glvalue expression is obtained by applying the unary * operator to
2199 // a pointer and the pointer is a null pointer value, the typeid expression
2200 // throws the std::bad_typeid exception.
2201 //
2202 // However, this paragraph's intent is not clear. We choose a very generous
2203 // interpretation which implores us to consider comma operators, conditional
2204 // operators, parentheses and other such constructs.
2205 if (CGF.CGM.getCXXABI().shouldTypeidBeNullChecked(
2206 isGLValueFromPointerDeref(E), SrcRecordTy)) {
2207 llvm::BasicBlock *BadTypeidBlock =
2208 CGF.createBasicBlock("typeid.bad_typeid");
2209 llvm::BasicBlock *EndBlock = CGF.createBasicBlock("typeid.end");
2210
2211 llvm::Value *IsNull = CGF.Builder.CreateIsNull(ThisPtr.getPointer());
2212 CGF.Builder.CreateCondBr(IsNull, BadTypeidBlock, EndBlock);
2213
2214 CGF.EmitBlock(BadTypeidBlock);
2215 CGF.CGM.getCXXABI().EmitBadTypeidCall(CGF);
2216 CGF.EmitBlock(EndBlock);
2217 }
2218
2219 return CGF.CGM.getCXXABI().EmitTypeid(CGF, SrcRecordTy, ThisPtr,
2220 StdTypeInfoPtrTy);
2221 }
2222
EmitCXXTypeidExpr(const CXXTypeidExpr * E)2223 llvm::Value *CodeGenFunction::EmitCXXTypeidExpr(const CXXTypeidExpr *E) {
2224 llvm::Type *PtrTy = llvm::PointerType::getUnqual(getLLVMContext());
2225 LangAS GlobAS = CGM.GetGlobalVarAddressSpace(nullptr);
2226
2227 auto MaybeASCast = [=](auto &&TypeInfo) {
2228 if (GlobAS == LangAS::Default)
2229 return TypeInfo;
2230 return getTargetHooks().performAddrSpaceCast(CGM,TypeInfo, GlobAS,
2231 LangAS::Default, PtrTy);
2232 };
2233
2234 if (E->isTypeOperand()) {
2235 llvm::Constant *TypeInfo =
2236 CGM.GetAddrOfRTTIDescriptor(E->getTypeOperand(getContext()));
2237 return MaybeASCast(TypeInfo);
2238 }
2239
2240 // C++ [expr.typeid]p2:
2241 // When typeid is applied to a glvalue expression whose type is a
2242 // polymorphic class type, the result refers to a std::type_info object
2243 // representing the type of the most derived object (that is, the dynamic
2244 // type) to which the glvalue refers.
2245 // If the operand is already most derived object, no need to look up vtable.
2246 if (E->isPotentiallyEvaluated() && !E->isMostDerived(getContext()))
2247 return EmitTypeidFromVTable(*this, E->getExprOperand(), PtrTy);
2248
2249 QualType OperandTy = E->getExprOperand()->getType();
2250 return MaybeASCast(CGM.GetAddrOfRTTIDescriptor(OperandTy));
2251 }
2252
EmitDynamicCastToNull(CodeGenFunction & CGF,QualType DestTy)2253 static llvm::Value *EmitDynamicCastToNull(CodeGenFunction &CGF,
2254 QualType DestTy) {
2255 llvm::Type *DestLTy = CGF.ConvertType(DestTy);
2256 if (DestTy->isPointerType())
2257 return llvm::Constant::getNullValue(DestLTy);
2258
2259 /// C++ [expr.dynamic.cast]p9:
2260 /// A failed cast to reference type throws std::bad_cast
2261 if (!CGF.CGM.getCXXABI().EmitBadCastCall(CGF))
2262 return nullptr;
2263
2264 CGF.Builder.ClearInsertionPoint();
2265 return llvm::PoisonValue::get(DestLTy);
2266 }
2267
EmitDynamicCast(Address ThisAddr,const CXXDynamicCastExpr * DCE)2268 llvm::Value *CodeGenFunction::EmitDynamicCast(Address ThisAddr,
2269 const CXXDynamicCastExpr *DCE) {
2270 CGM.EmitExplicitCastExprType(DCE, this);
2271 QualType DestTy = DCE->getTypeAsWritten();
2272
2273 QualType SrcTy = DCE->getSubExpr()->getType();
2274
2275 // C++ [expr.dynamic.cast]p7:
2276 // If T is "pointer to cv void," then the result is a pointer to the most
2277 // derived object pointed to by v.
2278 bool IsDynamicCastToVoid = DestTy->isVoidPointerType();
2279 QualType SrcRecordTy;
2280 QualType DestRecordTy;
2281 if (IsDynamicCastToVoid) {
2282 SrcRecordTy = SrcTy->getPointeeType();
2283 // No DestRecordTy.
2284 } else if (const PointerType *DestPTy = DestTy->getAs<PointerType>()) {
2285 SrcRecordTy = SrcTy->castAs<PointerType>()->getPointeeType();
2286 DestRecordTy = DestPTy->getPointeeType();
2287 } else {
2288 SrcRecordTy = SrcTy;
2289 DestRecordTy = DestTy->castAs<ReferenceType>()->getPointeeType();
2290 }
2291
2292 // C++ [class.cdtor]p5:
2293 // If the operand of the dynamic_cast refers to the object under
2294 // construction or destruction and the static type of the operand is not a
2295 // pointer to or object of the constructor or destructor’s own class or one
2296 // of its bases, the dynamic_cast results in undefined behavior.
2297 EmitTypeCheck(TCK_DynamicOperation, DCE->getExprLoc(), ThisAddr.getPointer(),
2298 SrcRecordTy);
2299
2300 if (DCE->isAlwaysNull()) {
2301 if (llvm::Value *T = EmitDynamicCastToNull(*this, DestTy)) {
2302 // Expression emission is expected to retain a valid insertion point.
2303 if (!Builder.GetInsertBlock())
2304 EmitBlock(createBasicBlock("dynamic_cast.unreachable"));
2305 return T;
2306 }
2307 }
2308
2309 assert(SrcRecordTy->isRecordType() && "source type must be a record type!");
2310
2311 // If the destination is effectively final, the cast succeeds if and only
2312 // if the dynamic type of the pointer is exactly the destination type.
2313 bool IsExact = !IsDynamicCastToVoid &&
2314 CGM.getCodeGenOpts().OptimizationLevel > 0 &&
2315 DestRecordTy->getAsCXXRecordDecl()->isEffectivelyFinal() &&
2316 CGM.getCXXABI().shouldEmitExactDynamicCast(DestRecordTy);
2317
2318 // C++ [expr.dynamic.cast]p4:
2319 // If the value of v is a null pointer value in the pointer case, the result
2320 // is the null pointer value of type T.
2321 bool ShouldNullCheckSrcValue =
2322 IsExact || CGM.getCXXABI().shouldDynamicCastCallBeNullChecked(
2323 SrcTy->isPointerType(), SrcRecordTy);
2324
2325 llvm::BasicBlock *CastNull = nullptr;
2326 llvm::BasicBlock *CastNotNull = nullptr;
2327 llvm::BasicBlock *CastEnd = createBasicBlock("dynamic_cast.end");
2328
2329 if (ShouldNullCheckSrcValue) {
2330 CastNull = createBasicBlock("dynamic_cast.null");
2331 CastNotNull = createBasicBlock("dynamic_cast.notnull");
2332
2333 llvm::Value *IsNull = Builder.CreateIsNull(ThisAddr.getPointer());
2334 Builder.CreateCondBr(IsNull, CastNull, CastNotNull);
2335 EmitBlock(CastNotNull);
2336 }
2337
2338 llvm::Value *Value;
2339 if (IsDynamicCastToVoid) {
2340 Value = CGM.getCXXABI().emitDynamicCastToVoid(*this, ThisAddr, SrcRecordTy);
2341 } else if (IsExact) {
2342 // If the destination type is effectively final, this pointer points to the
2343 // right type if and only if its vptr has the right value.
2344 Value = CGM.getCXXABI().emitExactDynamicCast(
2345 *this, ThisAddr, SrcRecordTy, DestTy, DestRecordTy, CastEnd, CastNull);
2346 } else {
2347 assert(DestRecordTy->isRecordType() &&
2348 "destination type must be a record type!");
2349 Value = CGM.getCXXABI().emitDynamicCastCall(*this, ThisAddr, SrcRecordTy,
2350 DestTy, DestRecordTy, CastEnd);
2351 }
2352 CastNotNull = Builder.GetInsertBlock();
2353
2354 llvm::Value *NullValue = nullptr;
2355 if (ShouldNullCheckSrcValue) {
2356 EmitBranch(CastEnd);
2357
2358 EmitBlock(CastNull);
2359 NullValue = EmitDynamicCastToNull(*this, DestTy);
2360 CastNull = Builder.GetInsertBlock();
2361
2362 EmitBranch(CastEnd);
2363 }
2364
2365 EmitBlock(CastEnd);
2366
2367 if (CastNull) {
2368 llvm::PHINode *PHI = Builder.CreatePHI(Value->getType(), 2);
2369 PHI->addIncoming(Value, CastNotNull);
2370 PHI->addIncoming(NullValue, CastNull);
2371
2372 Value = PHI;
2373 }
2374
2375 return Value;
2376 }
2377