1 //===--- CGClass.cpp - Emit LLVM Code for C++ classes -----------*- C++ -*-===//
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 C++ code generation of classes
10 //
11 //===----------------------------------------------------------------------===//
12
13 #include "CGBlocks.h"
14 #include "CGCXXABI.h"
15 #include "CGDebugInfo.h"
16 #include "CGRecordLayout.h"
17 #include "CodeGenFunction.h"
18 #include "TargetInfo.h"
19 #include "clang/AST/Attr.h"
20 #include "clang/AST/CXXInheritance.h"
21 #include "clang/AST/DeclTemplate.h"
22 #include "clang/AST/EvaluatedExprVisitor.h"
23 #include "clang/AST/RecordLayout.h"
24 #include "clang/AST/StmtCXX.h"
25 #include "clang/Basic/CodeGenOptions.h"
26 #include "clang/Basic/TargetBuiltins.h"
27 #include "clang/CodeGen/CGFunctionInfo.h"
28 #include "llvm/IR/Intrinsics.h"
29 #include "llvm/IR/Metadata.h"
30 #include "llvm/Transforms/Utils/SanitizerStats.h"
31
32 using namespace clang;
33 using namespace CodeGen;
34
35 /// Return the best known alignment for an unknown pointer to a
36 /// particular class.
getClassPointerAlignment(const CXXRecordDecl * RD)37 CharUnits CodeGenModule::getClassPointerAlignment(const CXXRecordDecl *RD) {
38 if (!RD->hasDefinition())
39 return CharUnits::One(); // Hopefully won't be used anywhere.
40
41 auto &layout = getContext().getASTRecordLayout(RD);
42
43 // If the class is final, then we know that the pointer points to an
44 // object of that type and can use the full alignment.
45 if (RD->isEffectivelyFinal())
46 return layout.getAlignment();
47
48 // Otherwise, we have to assume it could be a subclass.
49 return layout.getNonVirtualAlignment();
50 }
51
52 /// Return the smallest possible amount of storage that might be allocated
53 /// starting from the beginning of an object of a particular class.
54 ///
55 /// This may be smaller than sizeof(RD) if RD has virtual base classes.
getMinimumClassObjectSize(const CXXRecordDecl * RD)56 CharUnits CodeGenModule::getMinimumClassObjectSize(const CXXRecordDecl *RD) {
57 if (!RD->hasDefinition())
58 return CharUnits::One();
59
60 auto &layout = getContext().getASTRecordLayout(RD);
61
62 // If the class is final, then we know that the pointer points to an
63 // object of that type and can use the full alignment.
64 if (RD->isEffectivelyFinal())
65 return layout.getSize();
66
67 // Otherwise, we have to assume it could be a subclass.
68 return std::max(layout.getNonVirtualSize(), CharUnits::One());
69 }
70
71 /// Return the best known alignment for a pointer to a virtual base,
72 /// given the alignment of a pointer to the derived class.
getVBaseAlignment(CharUnits actualDerivedAlign,const CXXRecordDecl * derivedClass,const CXXRecordDecl * vbaseClass)73 CharUnits CodeGenModule::getVBaseAlignment(CharUnits actualDerivedAlign,
74 const CXXRecordDecl *derivedClass,
75 const CXXRecordDecl *vbaseClass) {
76 // The basic idea here is that an underaligned derived pointer might
77 // indicate an underaligned base pointer.
78
79 assert(vbaseClass->isCompleteDefinition());
80 auto &baseLayout = getContext().getASTRecordLayout(vbaseClass);
81 CharUnits expectedVBaseAlign = baseLayout.getNonVirtualAlignment();
82
83 return getDynamicOffsetAlignment(actualDerivedAlign, derivedClass,
84 expectedVBaseAlign);
85 }
86
87 CharUnits
getDynamicOffsetAlignment(CharUnits actualBaseAlign,const CXXRecordDecl * baseDecl,CharUnits expectedTargetAlign)88 CodeGenModule::getDynamicOffsetAlignment(CharUnits actualBaseAlign,
89 const CXXRecordDecl *baseDecl,
90 CharUnits expectedTargetAlign) {
91 // If the base is an incomplete type (which is, alas, possible with
92 // member pointers), be pessimistic.
93 if (!baseDecl->isCompleteDefinition())
94 return std::min(actualBaseAlign, expectedTargetAlign);
95
96 auto &baseLayout = getContext().getASTRecordLayout(baseDecl);
97 CharUnits expectedBaseAlign = baseLayout.getNonVirtualAlignment();
98
99 // If the class is properly aligned, assume the target offset is, too.
100 //
101 // This actually isn't necessarily the right thing to do --- if the
102 // class is a complete object, but it's only properly aligned for a
103 // base subobject, then the alignments of things relative to it are
104 // probably off as well. (Note that this requires the alignment of
105 // the target to be greater than the NV alignment of the derived
106 // class.)
107 //
108 // However, our approach to this kind of under-alignment can only
109 // ever be best effort; after all, we're never going to propagate
110 // alignments through variables or parameters. Note, in particular,
111 // that constructing a polymorphic type in an address that's less
112 // than pointer-aligned will generally trap in the constructor,
113 // unless we someday add some sort of attribute to change the
114 // assumed alignment of 'this'. So our goal here is pretty much
115 // just to allow the user to explicitly say that a pointer is
116 // under-aligned and then safely access its fields and vtables.
117 if (actualBaseAlign >= expectedBaseAlign) {
118 return expectedTargetAlign;
119 }
120
121 // Otherwise, we might be offset by an arbitrary multiple of the
122 // actual alignment. The correct adjustment is to take the min of
123 // the two alignments.
124 return std::min(actualBaseAlign, expectedTargetAlign);
125 }
126
LoadCXXThisAddress()127 Address CodeGenFunction::LoadCXXThisAddress() {
128 assert(CurFuncDecl && "loading 'this' without a func declaration?");
129 assert(isa<CXXMethodDecl>(CurFuncDecl));
130
131 // Lazily compute CXXThisAlignment.
132 if (CXXThisAlignment.isZero()) {
133 // Just use the best known alignment for the parent.
134 // TODO: if we're currently emitting a complete-object ctor/dtor,
135 // we can always use the complete-object alignment.
136 auto RD = cast<CXXMethodDecl>(CurFuncDecl)->getParent();
137 CXXThisAlignment = CGM.getClassPointerAlignment(RD);
138 }
139
140 return Address(LoadCXXThis(), CXXThisAlignment);
141 }
142
143 /// Emit the address of a field using a member data pointer.
144 ///
145 /// \param E Only used for emergency diagnostics
146 Address
EmitCXXMemberDataPointerAddress(const Expr * E,Address base,llvm::Value * memberPtr,const MemberPointerType * memberPtrType,LValueBaseInfo * BaseInfo,TBAAAccessInfo * TBAAInfo)147 CodeGenFunction::EmitCXXMemberDataPointerAddress(const Expr *E, Address base,
148 llvm::Value *memberPtr,
149 const MemberPointerType *memberPtrType,
150 LValueBaseInfo *BaseInfo,
151 TBAAAccessInfo *TBAAInfo) {
152 // Ask the ABI to compute the actual address.
153 llvm::Value *ptr =
154 CGM.getCXXABI().EmitMemberDataPointerAddress(*this, E, base,
155 memberPtr, memberPtrType);
156
157 QualType memberType = memberPtrType->getPointeeType();
158 CharUnits memberAlign =
159 CGM.getNaturalTypeAlignment(memberType, BaseInfo, TBAAInfo);
160 memberAlign =
161 CGM.getDynamicOffsetAlignment(base.getAlignment(),
162 memberPtrType->getClass()->getAsCXXRecordDecl(),
163 memberAlign);
164 return Address(ptr, memberAlign);
165 }
166
computeNonVirtualBaseClassOffset(const CXXRecordDecl * DerivedClass,CastExpr::path_const_iterator Start,CastExpr::path_const_iterator End)167 CharUnits CodeGenModule::computeNonVirtualBaseClassOffset(
168 const CXXRecordDecl *DerivedClass, CastExpr::path_const_iterator Start,
169 CastExpr::path_const_iterator End) {
170 CharUnits Offset = CharUnits::Zero();
171
172 const ASTContext &Context = getContext();
173 const CXXRecordDecl *RD = DerivedClass;
174
175 for (CastExpr::path_const_iterator I = Start; I != End; ++I) {
176 const CXXBaseSpecifier *Base = *I;
177 assert(!Base->isVirtual() && "Should not see virtual bases here!");
178
179 // Get the layout.
180 const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD);
181
182 const auto *BaseDecl =
183 cast<CXXRecordDecl>(Base->getType()->castAs<RecordType>()->getDecl());
184
185 // Add the offset.
186 Offset += Layout.getBaseClassOffset(BaseDecl);
187
188 RD = BaseDecl;
189 }
190
191 return Offset;
192 }
193
194 llvm::Constant *
GetNonVirtualBaseClassOffset(const CXXRecordDecl * ClassDecl,CastExpr::path_const_iterator PathBegin,CastExpr::path_const_iterator PathEnd)195 CodeGenModule::GetNonVirtualBaseClassOffset(const CXXRecordDecl *ClassDecl,
196 CastExpr::path_const_iterator PathBegin,
197 CastExpr::path_const_iterator PathEnd) {
198 assert(PathBegin != PathEnd && "Base path should not be empty!");
199
200 CharUnits Offset =
201 computeNonVirtualBaseClassOffset(ClassDecl, PathBegin, PathEnd);
202 if (Offset.isZero())
203 return nullptr;
204
205 llvm::Type *PtrDiffTy =
206 Types.ConvertType(getContext().getPointerDiffType());
207
208 return llvm::ConstantInt::get(PtrDiffTy, Offset.getQuantity());
209 }
210
211 /// Gets the address of a direct base class within a complete object.
212 /// This should only be used for (1) non-virtual bases or (2) virtual bases
213 /// when the type is known to be complete (e.g. in complete destructors).
214 ///
215 /// The object pointed to by 'This' is assumed to be non-null.
216 Address
GetAddressOfDirectBaseInCompleteClass(Address This,const CXXRecordDecl * Derived,const CXXRecordDecl * Base,bool BaseIsVirtual)217 CodeGenFunction::GetAddressOfDirectBaseInCompleteClass(Address This,
218 const CXXRecordDecl *Derived,
219 const CXXRecordDecl *Base,
220 bool BaseIsVirtual) {
221 // 'this' must be a pointer (in some address space) to Derived.
222 assert(This.getElementType() == ConvertType(Derived));
223
224 // Compute the offset of the virtual base.
225 CharUnits Offset;
226 const ASTRecordLayout &Layout = getContext().getASTRecordLayout(Derived);
227 if (BaseIsVirtual)
228 Offset = Layout.getVBaseClassOffset(Base);
229 else
230 Offset = Layout.getBaseClassOffset(Base);
231
232 // Shift and cast down to the base type.
233 // TODO: for complete types, this should be possible with a GEP.
234 Address V = This;
235 if (!Offset.isZero()) {
236 V = Builder.CreateElementBitCast(V, Int8Ty);
237 V = Builder.CreateConstInBoundsByteGEP(V, Offset);
238 }
239 V = Builder.CreateElementBitCast(V, ConvertType(Base));
240
241 return V;
242 }
243
244 static Address
ApplyNonVirtualAndVirtualOffset(CodeGenFunction & CGF,Address addr,CharUnits nonVirtualOffset,llvm::Value * virtualOffset,const CXXRecordDecl * derivedClass,const CXXRecordDecl * nearestVBase)245 ApplyNonVirtualAndVirtualOffset(CodeGenFunction &CGF, Address addr,
246 CharUnits nonVirtualOffset,
247 llvm::Value *virtualOffset,
248 const CXXRecordDecl *derivedClass,
249 const CXXRecordDecl *nearestVBase) {
250 // Assert that we have something to do.
251 assert(!nonVirtualOffset.isZero() || virtualOffset != nullptr);
252
253 // Compute the offset from the static and dynamic components.
254 llvm::Value *baseOffset;
255 if (!nonVirtualOffset.isZero()) {
256 llvm::Type *OffsetType =
257 (CGF.CGM.getTarget().getCXXABI().isItaniumFamily() &&
258 CGF.CGM.getItaniumVTableContext().isRelativeLayout())
259 ? CGF.Int32Ty
260 : CGF.PtrDiffTy;
261 baseOffset =
262 llvm::ConstantInt::get(OffsetType, nonVirtualOffset.getQuantity());
263 if (virtualOffset) {
264 baseOffset = CGF.Builder.CreateAdd(virtualOffset, baseOffset);
265 }
266 } else {
267 baseOffset = virtualOffset;
268 }
269
270 // Apply the base offset.
271 llvm::Value *ptr = addr.getPointer();
272 unsigned AddrSpace = ptr->getType()->getPointerAddressSpace();
273 ptr = CGF.Builder.CreateBitCast(ptr, CGF.Int8Ty->getPointerTo(AddrSpace));
274 ptr = CGF.Builder.CreateInBoundsGEP(ptr, baseOffset, "add.ptr");
275
276 // If we have a virtual component, the alignment of the result will
277 // be relative only to the known alignment of that vbase.
278 CharUnits alignment;
279 if (virtualOffset) {
280 assert(nearestVBase && "virtual offset without vbase?");
281 alignment = CGF.CGM.getVBaseAlignment(addr.getAlignment(),
282 derivedClass, nearestVBase);
283 } else {
284 alignment = addr.getAlignment();
285 }
286 alignment = alignment.alignmentAtOffset(nonVirtualOffset);
287
288 return Address(ptr, alignment);
289 }
290
GetAddressOfBaseClass(Address Value,const CXXRecordDecl * Derived,CastExpr::path_const_iterator PathBegin,CastExpr::path_const_iterator PathEnd,bool NullCheckValue,SourceLocation Loc)291 Address CodeGenFunction::GetAddressOfBaseClass(
292 Address Value, const CXXRecordDecl *Derived,
293 CastExpr::path_const_iterator PathBegin,
294 CastExpr::path_const_iterator PathEnd, bool NullCheckValue,
295 SourceLocation Loc) {
296 assert(PathBegin != PathEnd && "Base path should not be empty!");
297
298 CastExpr::path_const_iterator Start = PathBegin;
299 const CXXRecordDecl *VBase = nullptr;
300
301 // Sema has done some convenient canonicalization here: if the
302 // access path involved any virtual steps, the conversion path will
303 // *start* with a step down to the correct virtual base subobject,
304 // and hence will not require any further steps.
305 if ((*Start)->isVirtual()) {
306 VBase = cast<CXXRecordDecl>(
307 (*Start)->getType()->castAs<RecordType>()->getDecl());
308 ++Start;
309 }
310
311 // Compute the static offset of the ultimate destination within its
312 // allocating subobject (the virtual base, if there is one, or else
313 // the "complete" object that we see).
314 CharUnits NonVirtualOffset = CGM.computeNonVirtualBaseClassOffset(
315 VBase ? VBase : Derived, Start, PathEnd);
316
317 // If there's a virtual step, we can sometimes "devirtualize" it.
318 // For now, that's limited to when the derived type is final.
319 // TODO: "devirtualize" this for accesses to known-complete objects.
320 if (VBase && Derived->hasAttr<FinalAttr>()) {
321 const ASTRecordLayout &layout = getContext().getASTRecordLayout(Derived);
322 CharUnits vBaseOffset = layout.getVBaseClassOffset(VBase);
323 NonVirtualOffset += vBaseOffset;
324 VBase = nullptr; // we no longer have a virtual step
325 }
326
327 // Get the base pointer type.
328 llvm::Type *BasePtrTy =
329 ConvertType((PathEnd[-1])->getType())
330 ->getPointerTo(Value.getType()->getPointerAddressSpace());
331
332 QualType DerivedTy = getContext().getRecordType(Derived);
333 CharUnits DerivedAlign = CGM.getClassPointerAlignment(Derived);
334
335 // If the static offset is zero and we don't have a virtual step,
336 // just do a bitcast; null checks are unnecessary.
337 if (NonVirtualOffset.isZero() && !VBase) {
338 if (sanitizePerformTypeCheck()) {
339 SanitizerSet SkippedChecks;
340 SkippedChecks.set(SanitizerKind::Null, !NullCheckValue);
341 EmitTypeCheck(TCK_Upcast, Loc, Value.getPointer(),
342 DerivedTy, DerivedAlign, SkippedChecks);
343 }
344 return Builder.CreateBitCast(Value, BasePtrTy);
345 }
346
347 llvm::BasicBlock *origBB = nullptr;
348 llvm::BasicBlock *endBB = nullptr;
349
350 // Skip over the offset (and the vtable load) if we're supposed to
351 // null-check the pointer.
352 if (NullCheckValue) {
353 origBB = Builder.GetInsertBlock();
354 llvm::BasicBlock *notNullBB = createBasicBlock("cast.notnull");
355 endBB = createBasicBlock("cast.end");
356
357 llvm::Value *isNull = Builder.CreateIsNull(Value.getPointer());
358 Builder.CreateCondBr(isNull, endBB, notNullBB);
359 EmitBlock(notNullBB);
360 }
361
362 if (sanitizePerformTypeCheck()) {
363 SanitizerSet SkippedChecks;
364 SkippedChecks.set(SanitizerKind::Null, true);
365 EmitTypeCheck(VBase ? TCK_UpcastToVirtualBase : TCK_Upcast, Loc,
366 Value.getPointer(), DerivedTy, DerivedAlign, SkippedChecks);
367 }
368
369 // Compute the virtual offset.
370 llvm::Value *VirtualOffset = nullptr;
371 if (VBase) {
372 VirtualOffset =
373 CGM.getCXXABI().GetVirtualBaseClassOffset(*this, Value, Derived, VBase);
374 }
375
376 // Apply both offsets.
377 Value = ApplyNonVirtualAndVirtualOffset(*this, Value, NonVirtualOffset,
378 VirtualOffset, Derived, VBase);
379
380 // Cast to the destination type.
381 Value = Builder.CreateBitCast(Value, BasePtrTy);
382
383 // Build a phi if we needed a null check.
384 if (NullCheckValue) {
385 llvm::BasicBlock *notNullBB = Builder.GetInsertBlock();
386 Builder.CreateBr(endBB);
387 EmitBlock(endBB);
388
389 llvm::PHINode *PHI = Builder.CreatePHI(BasePtrTy, 2, "cast.result");
390 PHI->addIncoming(Value.getPointer(), notNullBB);
391 PHI->addIncoming(llvm::Constant::getNullValue(BasePtrTy), origBB);
392 Value = Address(PHI, Value.getAlignment());
393 }
394
395 return Value;
396 }
397
398 Address
GetAddressOfDerivedClass(Address BaseAddr,const CXXRecordDecl * Derived,CastExpr::path_const_iterator PathBegin,CastExpr::path_const_iterator PathEnd,bool NullCheckValue)399 CodeGenFunction::GetAddressOfDerivedClass(Address BaseAddr,
400 const CXXRecordDecl *Derived,
401 CastExpr::path_const_iterator PathBegin,
402 CastExpr::path_const_iterator PathEnd,
403 bool NullCheckValue) {
404 assert(PathBegin != PathEnd && "Base path should not be empty!");
405
406 QualType DerivedTy =
407 getContext().getCanonicalType(getContext().getTagDeclType(Derived));
408 unsigned AddrSpace =
409 BaseAddr.getPointer()->getType()->getPointerAddressSpace();
410 llvm::Type *DerivedPtrTy = ConvertType(DerivedTy)->getPointerTo(AddrSpace);
411
412 llvm::Value *NonVirtualOffset =
413 CGM.GetNonVirtualBaseClassOffset(Derived, PathBegin, PathEnd);
414
415 if (!NonVirtualOffset) {
416 // No offset, we can just cast back.
417 return Builder.CreateBitCast(BaseAddr, DerivedPtrTy);
418 }
419
420 llvm::BasicBlock *CastNull = nullptr;
421 llvm::BasicBlock *CastNotNull = nullptr;
422 llvm::BasicBlock *CastEnd = nullptr;
423
424 if (NullCheckValue) {
425 CastNull = createBasicBlock("cast.null");
426 CastNotNull = createBasicBlock("cast.notnull");
427 CastEnd = createBasicBlock("cast.end");
428
429 llvm::Value *IsNull = Builder.CreateIsNull(BaseAddr.getPointer());
430 Builder.CreateCondBr(IsNull, CastNull, CastNotNull);
431 EmitBlock(CastNotNull);
432 }
433
434 // Apply the offset.
435 llvm::Value *Value = Builder.CreateBitCast(BaseAddr.getPointer(), Int8PtrTy);
436 Value = Builder.CreateInBoundsGEP(Value, Builder.CreateNeg(NonVirtualOffset),
437 "sub.ptr");
438
439 // Just cast.
440 Value = Builder.CreateBitCast(Value, DerivedPtrTy);
441
442 // Produce a PHI if we had a null-check.
443 if (NullCheckValue) {
444 Builder.CreateBr(CastEnd);
445 EmitBlock(CastNull);
446 Builder.CreateBr(CastEnd);
447 EmitBlock(CastEnd);
448
449 llvm::PHINode *PHI = Builder.CreatePHI(Value->getType(), 2);
450 PHI->addIncoming(Value, CastNotNull);
451 PHI->addIncoming(llvm::Constant::getNullValue(Value->getType()), CastNull);
452 Value = PHI;
453 }
454
455 return Address(Value, CGM.getClassPointerAlignment(Derived));
456 }
457
GetVTTParameter(GlobalDecl GD,bool ForVirtualBase,bool Delegating)458 llvm::Value *CodeGenFunction::GetVTTParameter(GlobalDecl GD,
459 bool ForVirtualBase,
460 bool Delegating) {
461 if (!CGM.getCXXABI().NeedsVTTParameter(GD)) {
462 // This constructor/destructor does not need a VTT parameter.
463 return nullptr;
464 }
465
466 const CXXRecordDecl *RD = cast<CXXMethodDecl>(CurCodeDecl)->getParent();
467 const CXXRecordDecl *Base = cast<CXXMethodDecl>(GD.getDecl())->getParent();
468
469 llvm::Value *VTT;
470
471 uint64_t SubVTTIndex;
472
473 if (Delegating) {
474 // If this is a delegating constructor call, just load the VTT.
475 return LoadCXXVTT();
476 } else if (RD == Base) {
477 // If the record matches the base, this is the complete ctor/dtor
478 // variant calling the base variant in a class with virtual bases.
479 assert(!CGM.getCXXABI().NeedsVTTParameter(CurGD) &&
480 "doing no-op VTT offset in base dtor/ctor?");
481 assert(!ForVirtualBase && "Can't have same class as virtual base!");
482 SubVTTIndex = 0;
483 } else {
484 const ASTRecordLayout &Layout = getContext().getASTRecordLayout(RD);
485 CharUnits BaseOffset = ForVirtualBase ?
486 Layout.getVBaseClassOffset(Base) :
487 Layout.getBaseClassOffset(Base);
488
489 SubVTTIndex =
490 CGM.getVTables().getSubVTTIndex(RD, BaseSubobject(Base, BaseOffset));
491 assert(SubVTTIndex != 0 && "Sub-VTT index must be greater than zero!");
492 }
493
494 if (CGM.getCXXABI().NeedsVTTParameter(CurGD)) {
495 // A VTT parameter was passed to the constructor, use it.
496 VTT = LoadCXXVTT();
497 VTT = Builder.CreateConstInBoundsGEP1_64(VTT, SubVTTIndex);
498 } else {
499 // We're the complete constructor, so get the VTT by name.
500 VTT = CGM.getVTables().GetAddrOfVTT(RD);
501 VTT = Builder.CreateConstInBoundsGEP2_64(VTT, 0, SubVTTIndex);
502 }
503
504 return VTT;
505 }
506
507 namespace {
508 /// Call the destructor for a direct base class.
509 struct CallBaseDtor final : EHScopeStack::Cleanup {
510 const CXXRecordDecl *BaseClass;
511 bool BaseIsVirtual;
CallBaseDtor__anon463df5f00111::CallBaseDtor512 CallBaseDtor(const CXXRecordDecl *Base, bool BaseIsVirtual)
513 : BaseClass(Base), BaseIsVirtual(BaseIsVirtual) {}
514
Emit__anon463df5f00111::CallBaseDtor515 void Emit(CodeGenFunction &CGF, Flags flags) override {
516 const CXXRecordDecl *DerivedClass =
517 cast<CXXMethodDecl>(CGF.CurCodeDecl)->getParent();
518
519 const CXXDestructorDecl *D = BaseClass->getDestructor();
520 // We are already inside a destructor, so presumably the object being
521 // destroyed should have the expected type.
522 QualType ThisTy = D->getThisObjectType();
523 Address Addr =
524 CGF.GetAddressOfDirectBaseInCompleteClass(CGF.LoadCXXThisAddress(),
525 DerivedClass, BaseClass,
526 BaseIsVirtual);
527 CGF.EmitCXXDestructorCall(D, Dtor_Base, BaseIsVirtual,
528 /*Delegating=*/false, Addr, ThisTy);
529 }
530 };
531
532 /// A visitor which checks whether an initializer uses 'this' in a
533 /// way which requires the vtable to be properly set.
534 struct DynamicThisUseChecker : ConstEvaluatedExprVisitor<DynamicThisUseChecker> {
535 typedef ConstEvaluatedExprVisitor<DynamicThisUseChecker> super;
536
537 bool UsesThis;
538
DynamicThisUseChecker__anon463df5f00111::DynamicThisUseChecker539 DynamicThisUseChecker(const ASTContext &C) : super(C), UsesThis(false) {}
540
541 // Black-list all explicit and implicit references to 'this'.
542 //
543 // Do we need to worry about external references to 'this' derived
544 // from arbitrary code? If so, then anything which runs arbitrary
545 // external code might potentially access the vtable.
VisitCXXThisExpr__anon463df5f00111::DynamicThisUseChecker546 void VisitCXXThisExpr(const CXXThisExpr *E) { UsesThis = true; }
547 };
548 } // end anonymous namespace
549
BaseInitializerUsesThis(ASTContext & C,const Expr * Init)550 static bool BaseInitializerUsesThis(ASTContext &C, const Expr *Init) {
551 DynamicThisUseChecker Checker(C);
552 Checker.Visit(Init);
553 return Checker.UsesThis;
554 }
555
EmitBaseInitializer(CodeGenFunction & CGF,const CXXRecordDecl * ClassDecl,CXXCtorInitializer * BaseInit)556 static void EmitBaseInitializer(CodeGenFunction &CGF,
557 const CXXRecordDecl *ClassDecl,
558 CXXCtorInitializer *BaseInit) {
559 assert(BaseInit->isBaseInitializer() &&
560 "Must have base initializer!");
561
562 Address ThisPtr = CGF.LoadCXXThisAddress();
563
564 const Type *BaseType = BaseInit->getBaseClass();
565 const auto *BaseClassDecl =
566 cast<CXXRecordDecl>(BaseType->castAs<RecordType>()->getDecl());
567
568 bool isBaseVirtual = BaseInit->isBaseVirtual();
569
570 // If the initializer for the base (other than the constructor
571 // itself) accesses 'this' in any way, we need to initialize the
572 // vtables.
573 if (BaseInitializerUsesThis(CGF.getContext(), BaseInit->getInit()))
574 CGF.InitializeVTablePointers(ClassDecl);
575
576 // We can pretend to be a complete class because it only matters for
577 // virtual bases, and we only do virtual bases for complete ctors.
578 Address V =
579 CGF.GetAddressOfDirectBaseInCompleteClass(ThisPtr, ClassDecl,
580 BaseClassDecl,
581 isBaseVirtual);
582 AggValueSlot AggSlot =
583 AggValueSlot::forAddr(
584 V, Qualifiers(),
585 AggValueSlot::IsDestructed,
586 AggValueSlot::DoesNotNeedGCBarriers,
587 AggValueSlot::IsNotAliased,
588 CGF.getOverlapForBaseInit(ClassDecl, BaseClassDecl, isBaseVirtual));
589
590 CGF.EmitAggExpr(BaseInit->getInit(), AggSlot);
591
592 if (CGF.CGM.getLangOpts().Exceptions &&
593 !BaseClassDecl->hasTrivialDestructor())
594 CGF.EHStack.pushCleanup<CallBaseDtor>(EHCleanup, BaseClassDecl,
595 isBaseVirtual);
596 }
597
isMemcpyEquivalentSpecialMember(const CXXMethodDecl * D)598 static bool isMemcpyEquivalentSpecialMember(const CXXMethodDecl *D) {
599 auto *CD = dyn_cast<CXXConstructorDecl>(D);
600 if (!(CD && CD->isCopyOrMoveConstructor()) &&
601 !D->isCopyAssignmentOperator() && !D->isMoveAssignmentOperator())
602 return false;
603
604 // We can emit a memcpy for a trivial copy or move constructor/assignment.
605 if (D->isTrivial() && !D->getParent()->mayInsertExtraPadding())
606 return true;
607
608 // We *must* emit a memcpy for a defaulted union copy or move op.
609 if (D->getParent()->isUnion() && D->isDefaulted())
610 return true;
611
612 return false;
613 }
614
EmitLValueForAnyFieldInitialization(CodeGenFunction & CGF,CXXCtorInitializer * MemberInit,LValue & LHS)615 static void EmitLValueForAnyFieldInitialization(CodeGenFunction &CGF,
616 CXXCtorInitializer *MemberInit,
617 LValue &LHS) {
618 FieldDecl *Field = MemberInit->getAnyMember();
619 if (MemberInit->isIndirectMemberInitializer()) {
620 // If we are initializing an anonymous union field, drill down to the field.
621 IndirectFieldDecl *IndirectField = MemberInit->getIndirectMember();
622 for (const auto *I : IndirectField->chain())
623 LHS = CGF.EmitLValueForFieldInitialization(LHS, cast<FieldDecl>(I));
624 } else {
625 LHS = CGF.EmitLValueForFieldInitialization(LHS, Field);
626 }
627 }
628
EmitMemberInitializer(CodeGenFunction & CGF,const CXXRecordDecl * ClassDecl,CXXCtorInitializer * MemberInit,const CXXConstructorDecl * Constructor,FunctionArgList & Args)629 static void EmitMemberInitializer(CodeGenFunction &CGF,
630 const CXXRecordDecl *ClassDecl,
631 CXXCtorInitializer *MemberInit,
632 const CXXConstructorDecl *Constructor,
633 FunctionArgList &Args) {
634 ApplyDebugLocation Loc(CGF, MemberInit->getSourceLocation());
635 assert(MemberInit->isAnyMemberInitializer() &&
636 "Must have member initializer!");
637 assert(MemberInit->getInit() && "Must have initializer!");
638
639 // non-static data member initializers.
640 FieldDecl *Field = MemberInit->getAnyMember();
641 QualType FieldType = Field->getType();
642
643 llvm::Value *ThisPtr = CGF.LoadCXXThis();
644 QualType RecordTy = CGF.getContext().getTypeDeclType(ClassDecl);
645 LValue LHS;
646
647 // If a base constructor is being emitted, create an LValue that has the
648 // non-virtual alignment.
649 if (CGF.CurGD.getCtorType() == Ctor_Base)
650 LHS = CGF.MakeNaturalAlignPointeeAddrLValue(ThisPtr, RecordTy);
651 else
652 LHS = CGF.MakeNaturalAlignAddrLValue(ThisPtr, RecordTy);
653
654 EmitLValueForAnyFieldInitialization(CGF, MemberInit, LHS);
655
656 // Special case: if we are in a copy or move constructor, and we are copying
657 // an array of PODs or classes with trivial copy constructors, ignore the
658 // AST and perform the copy we know is equivalent.
659 // FIXME: This is hacky at best... if we had a bit more explicit information
660 // in the AST, we could generalize it more easily.
661 const ConstantArrayType *Array
662 = CGF.getContext().getAsConstantArrayType(FieldType);
663 if (Array && Constructor->isDefaulted() &&
664 Constructor->isCopyOrMoveConstructor()) {
665 QualType BaseElementTy = CGF.getContext().getBaseElementType(Array);
666 CXXConstructExpr *CE = dyn_cast<CXXConstructExpr>(MemberInit->getInit());
667 if (BaseElementTy.isPODType(CGF.getContext()) ||
668 (CE && isMemcpyEquivalentSpecialMember(CE->getConstructor()))) {
669 unsigned SrcArgIndex =
670 CGF.CGM.getCXXABI().getSrcArgforCopyCtor(Constructor, Args);
671 llvm::Value *SrcPtr
672 = CGF.Builder.CreateLoad(CGF.GetAddrOfLocalVar(Args[SrcArgIndex]));
673 LValue ThisRHSLV = CGF.MakeNaturalAlignAddrLValue(SrcPtr, RecordTy);
674 LValue Src = CGF.EmitLValueForFieldInitialization(ThisRHSLV, Field);
675
676 // Copy the aggregate.
677 CGF.EmitAggregateCopy(LHS, Src, FieldType, CGF.getOverlapForFieldInit(Field),
678 LHS.isVolatileQualified());
679 // Ensure that we destroy the objects if an exception is thrown later in
680 // the constructor.
681 QualType::DestructionKind dtorKind = FieldType.isDestructedType();
682 if (CGF.needsEHCleanup(dtorKind))
683 CGF.pushEHDestroy(dtorKind, LHS.getAddress(CGF), FieldType);
684 return;
685 }
686 }
687
688 CGF.EmitInitializerForField(Field, LHS, MemberInit->getInit());
689 }
690
EmitInitializerForField(FieldDecl * Field,LValue LHS,Expr * Init)691 void CodeGenFunction::EmitInitializerForField(FieldDecl *Field, LValue LHS,
692 Expr *Init) {
693 QualType FieldType = Field->getType();
694 switch (getEvaluationKind(FieldType)) {
695 case TEK_Scalar:
696 if (LHS.isSimple()) {
697 EmitExprAsInit(Init, Field, LHS, false);
698 } else {
699 RValue RHS = RValue::get(EmitScalarExpr(Init));
700 EmitStoreThroughLValue(RHS, LHS);
701 }
702 break;
703 case TEK_Complex:
704 EmitComplexExprIntoLValue(Init, LHS, /*isInit*/ true);
705 break;
706 case TEK_Aggregate: {
707 AggValueSlot Slot = AggValueSlot::forLValue(
708 LHS, *this, AggValueSlot::IsDestructed,
709 AggValueSlot::DoesNotNeedGCBarriers, AggValueSlot::IsNotAliased,
710 getOverlapForFieldInit(Field), AggValueSlot::IsNotZeroed,
711 // Checks are made by the code that calls constructor.
712 AggValueSlot::IsSanitizerChecked);
713 EmitAggExpr(Init, Slot);
714 break;
715 }
716 }
717
718 // Ensure that we destroy this object if an exception is thrown
719 // later in the constructor.
720 QualType::DestructionKind dtorKind = FieldType.isDestructedType();
721 if (needsEHCleanup(dtorKind))
722 pushEHDestroy(dtorKind, LHS.getAddress(*this), FieldType);
723 }
724
725 /// Checks whether the given constructor is a valid subject for the
726 /// complete-to-base constructor delegation optimization, i.e.
727 /// emitting the complete constructor as a simple call to the base
728 /// constructor.
IsConstructorDelegationValid(const CXXConstructorDecl * Ctor)729 bool CodeGenFunction::IsConstructorDelegationValid(
730 const CXXConstructorDecl *Ctor) {
731
732 // Currently we disable the optimization for classes with virtual
733 // bases because (1) the addresses of parameter variables need to be
734 // consistent across all initializers but (2) the delegate function
735 // call necessarily creates a second copy of the parameter variable.
736 //
737 // The limiting example (purely theoretical AFAIK):
738 // struct A { A(int &c) { c++; } };
739 // struct B : virtual A {
740 // B(int count) : A(count) { printf("%d\n", count); }
741 // };
742 // ...although even this example could in principle be emitted as a
743 // delegation since the address of the parameter doesn't escape.
744 if (Ctor->getParent()->getNumVBases()) {
745 // TODO: white-list trivial vbase initializers. This case wouldn't
746 // be subject to the restrictions below.
747
748 // TODO: white-list cases where:
749 // - there are no non-reference parameters to the constructor
750 // - the initializers don't access any non-reference parameters
751 // - the initializers don't take the address of non-reference
752 // parameters
753 // - etc.
754 // If we ever add any of the above cases, remember that:
755 // - function-try-blocks will always exclude this optimization
756 // - we need to perform the constructor prologue and cleanup in
757 // EmitConstructorBody.
758
759 return false;
760 }
761
762 // We also disable the optimization for variadic functions because
763 // it's impossible to "re-pass" varargs.
764 if (Ctor->getType()->castAs<FunctionProtoType>()->isVariadic())
765 return false;
766
767 // FIXME: Decide if we can do a delegation of a delegating constructor.
768 if (Ctor->isDelegatingConstructor())
769 return false;
770
771 return true;
772 }
773
774 // Emit code in ctor (Prologue==true) or dtor (Prologue==false)
775 // to poison the extra field paddings inserted under
776 // -fsanitize-address-field-padding=1|2.
EmitAsanPrologueOrEpilogue(bool Prologue)777 void CodeGenFunction::EmitAsanPrologueOrEpilogue(bool Prologue) {
778 ASTContext &Context = getContext();
779 const CXXRecordDecl *ClassDecl =
780 Prologue ? cast<CXXConstructorDecl>(CurGD.getDecl())->getParent()
781 : cast<CXXDestructorDecl>(CurGD.getDecl())->getParent();
782 if (!ClassDecl->mayInsertExtraPadding()) return;
783
784 struct SizeAndOffset {
785 uint64_t Size;
786 uint64_t Offset;
787 };
788
789 unsigned PtrSize = CGM.getDataLayout().getPointerSizeInBits();
790 const ASTRecordLayout &Info = Context.getASTRecordLayout(ClassDecl);
791
792 // Populate sizes and offsets of fields.
793 SmallVector<SizeAndOffset, 16> SSV(Info.getFieldCount());
794 for (unsigned i = 0, e = Info.getFieldCount(); i != e; ++i)
795 SSV[i].Offset =
796 Context.toCharUnitsFromBits(Info.getFieldOffset(i)).getQuantity();
797
798 size_t NumFields = 0;
799 for (const auto *Field : ClassDecl->fields()) {
800 const FieldDecl *D = Field;
801 std::pair<CharUnits, CharUnits> FieldInfo =
802 Context.getTypeInfoInChars(D->getType());
803 CharUnits FieldSize = FieldInfo.first;
804 assert(NumFields < SSV.size());
805 SSV[NumFields].Size = D->isBitField() ? 0 : FieldSize.getQuantity();
806 NumFields++;
807 }
808 assert(NumFields == SSV.size());
809 if (SSV.size() <= 1) return;
810
811 // We will insert calls to __asan_* run-time functions.
812 // LLVM AddressSanitizer pass may decide to inline them later.
813 llvm::Type *Args[2] = {IntPtrTy, IntPtrTy};
814 llvm::FunctionType *FTy =
815 llvm::FunctionType::get(CGM.VoidTy, Args, false);
816 llvm::FunctionCallee F = CGM.CreateRuntimeFunction(
817 FTy, Prologue ? "__asan_poison_intra_object_redzone"
818 : "__asan_unpoison_intra_object_redzone");
819
820 llvm::Value *ThisPtr = LoadCXXThis();
821 ThisPtr = Builder.CreatePtrToInt(ThisPtr, IntPtrTy);
822 uint64_t TypeSize = Info.getNonVirtualSize().getQuantity();
823 // For each field check if it has sufficient padding,
824 // if so (un)poison it with a call.
825 for (size_t i = 0; i < SSV.size(); i++) {
826 uint64_t AsanAlignment = 8;
827 uint64_t NextField = i == SSV.size() - 1 ? TypeSize : SSV[i + 1].Offset;
828 uint64_t PoisonSize = NextField - SSV[i].Offset - SSV[i].Size;
829 uint64_t EndOffset = SSV[i].Offset + SSV[i].Size;
830 if (PoisonSize < AsanAlignment || !SSV[i].Size ||
831 (NextField % AsanAlignment) != 0)
832 continue;
833 Builder.CreateCall(
834 F, {Builder.CreateAdd(ThisPtr, Builder.getIntN(PtrSize, EndOffset)),
835 Builder.getIntN(PtrSize, PoisonSize)});
836 }
837 }
838
839 /// EmitConstructorBody - Emits the body of the current constructor.
EmitConstructorBody(FunctionArgList & Args)840 void CodeGenFunction::EmitConstructorBody(FunctionArgList &Args) {
841 EmitAsanPrologueOrEpilogue(true);
842 const CXXConstructorDecl *Ctor = cast<CXXConstructorDecl>(CurGD.getDecl());
843 CXXCtorType CtorType = CurGD.getCtorType();
844
845 assert((CGM.getTarget().getCXXABI().hasConstructorVariants() ||
846 CtorType == Ctor_Complete) &&
847 "can only generate complete ctor for this ABI");
848
849 // Before we go any further, try the complete->base constructor
850 // delegation optimization.
851 if (CtorType == Ctor_Complete && IsConstructorDelegationValid(Ctor) &&
852 CGM.getTarget().getCXXABI().hasConstructorVariants()) {
853 EmitDelegateCXXConstructorCall(Ctor, Ctor_Base, Args, Ctor->getEndLoc());
854 return;
855 }
856
857 const FunctionDecl *Definition = nullptr;
858 Stmt *Body = Ctor->getBody(Definition);
859 assert(Definition == Ctor && "emitting wrong constructor body");
860
861 // Enter the function-try-block before the constructor prologue if
862 // applicable.
863 bool IsTryBody = (Body && isa<CXXTryStmt>(Body));
864 if (IsTryBody)
865 EnterCXXTryStmt(*cast<CXXTryStmt>(Body), true);
866
867 incrementProfileCounter(Body);
868
869 RunCleanupsScope RunCleanups(*this);
870
871 // TODO: in restricted cases, we can emit the vbase initializers of
872 // a complete ctor and then delegate to the base ctor.
873
874 // Emit the constructor prologue, i.e. the base and member
875 // initializers.
876 EmitCtorPrologue(Ctor, CtorType, Args);
877
878 // Emit the body of the statement.
879 if (IsTryBody)
880 EmitStmt(cast<CXXTryStmt>(Body)->getTryBlock());
881 else if (Body)
882 EmitStmt(Body);
883
884 // Emit any cleanup blocks associated with the member or base
885 // initializers, which includes (along the exceptional path) the
886 // destructors for those members and bases that were fully
887 // constructed.
888 RunCleanups.ForceCleanup();
889
890 if (IsTryBody)
891 ExitCXXTryStmt(*cast<CXXTryStmt>(Body), true);
892 }
893
894 namespace {
895 /// RAII object to indicate that codegen is copying the value representation
896 /// instead of the object representation. Useful when copying a struct or
897 /// class which has uninitialized members and we're only performing
898 /// lvalue-to-rvalue conversion on the object but not its members.
899 class CopyingValueRepresentation {
900 public:
CopyingValueRepresentation(CodeGenFunction & CGF)901 explicit CopyingValueRepresentation(CodeGenFunction &CGF)
902 : CGF(CGF), OldSanOpts(CGF.SanOpts) {
903 CGF.SanOpts.set(SanitizerKind::Bool, false);
904 CGF.SanOpts.set(SanitizerKind::Enum, false);
905 }
~CopyingValueRepresentation()906 ~CopyingValueRepresentation() {
907 CGF.SanOpts = OldSanOpts;
908 }
909 private:
910 CodeGenFunction &CGF;
911 SanitizerSet OldSanOpts;
912 };
913 } // end anonymous namespace
914
915 namespace {
916 class FieldMemcpyizer {
917 public:
FieldMemcpyizer(CodeGenFunction & CGF,const CXXRecordDecl * ClassDecl,const VarDecl * SrcRec)918 FieldMemcpyizer(CodeGenFunction &CGF, const CXXRecordDecl *ClassDecl,
919 const VarDecl *SrcRec)
920 : CGF(CGF), ClassDecl(ClassDecl), SrcRec(SrcRec),
921 RecLayout(CGF.getContext().getASTRecordLayout(ClassDecl)),
922 FirstField(nullptr), LastField(nullptr), FirstFieldOffset(0),
923 LastFieldOffset(0), LastAddedFieldIndex(0) {}
924
isMemcpyableField(FieldDecl * F) const925 bool isMemcpyableField(FieldDecl *F) const {
926 // Never memcpy fields when we are adding poisoned paddings.
927 if (CGF.getContext().getLangOpts().SanitizeAddressFieldPadding)
928 return false;
929 Qualifiers Qual = F->getType().getQualifiers();
930 if (Qual.hasVolatile() || Qual.hasObjCLifetime())
931 return false;
932 return true;
933 }
934
addMemcpyableField(FieldDecl * F)935 void addMemcpyableField(FieldDecl *F) {
936 if (F->isZeroSize(CGF.getContext()))
937 return;
938 if (!FirstField)
939 addInitialField(F);
940 else
941 addNextField(F);
942 }
943
getMemcpySize(uint64_t FirstByteOffset) const944 CharUnits getMemcpySize(uint64_t FirstByteOffset) const {
945 ASTContext &Ctx = CGF.getContext();
946 unsigned LastFieldSize =
947 LastField->isBitField()
948 ? LastField->getBitWidthValue(Ctx)
949 : Ctx.toBits(
950 Ctx.getTypeInfoDataSizeInChars(LastField->getType()).first);
951 uint64_t MemcpySizeBits = LastFieldOffset + LastFieldSize -
952 FirstByteOffset + Ctx.getCharWidth() - 1;
953 CharUnits MemcpySize = Ctx.toCharUnitsFromBits(MemcpySizeBits);
954 return MemcpySize;
955 }
956
emitMemcpy()957 void emitMemcpy() {
958 // Give the subclass a chance to bail out if it feels the memcpy isn't
959 // worth it (e.g. Hasn't aggregated enough data).
960 if (!FirstField) {
961 return;
962 }
963
964 uint64_t FirstByteOffset;
965 if (FirstField->isBitField()) {
966 const CGRecordLayout &RL =
967 CGF.getTypes().getCGRecordLayout(FirstField->getParent());
968 const CGBitFieldInfo &BFInfo = RL.getBitFieldInfo(FirstField);
969 // FirstFieldOffset is not appropriate for bitfields,
970 // we need to use the storage offset instead.
971 FirstByteOffset = CGF.getContext().toBits(BFInfo.StorageOffset);
972 } else {
973 FirstByteOffset = FirstFieldOffset;
974 }
975
976 CharUnits MemcpySize = getMemcpySize(FirstByteOffset);
977 QualType RecordTy = CGF.getContext().getTypeDeclType(ClassDecl);
978 Address ThisPtr = CGF.LoadCXXThisAddress();
979 LValue DestLV = CGF.MakeAddrLValue(ThisPtr, RecordTy);
980 LValue Dest = CGF.EmitLValueForFieldInitialization(DestLV, FirstField);
981 llvm::Value *SrcPtr = CGF.Builder.CreateLoad(CGF.GetAddrOfLocalVar(SrcRec));
982 LValue SrcLV = CGF.MakeNaturalAlignAddrLValue(SrcPtr, RecordTy);
983 LValue Src = CGF.EmitLValueForFieldInitialization(SrcLV, FirstField);
984
985 emitMemcpyIR(
986 Dest.isBitField() ? Dest.getBitFieldAddress() : Dest.getAddress(CGF),
987 Src.isBitField() ? Src.getBitFieldAddress() : Src.getAddress(CGF),
988 MemcpySize);
989 reset();
990 }
991
reset()992 void reset() {
993 FirstField = nullptr;
994 }
995
996 protected:
997 CodeGenFunction &CGF;
998 const CXXRecordDecl *ClassDecl;
999
1000 private:
emitMemcpyIR(Address DestPtr,Address SrcPtr,CharUnits Size)1001 void emitMemcpyIR(Address DestPtr, Address SrcPtr, CharUnits Size) {
1002 llvm::PointerType *DPT = DestPtr.getType();
1003 llvm::Type *DBP =
1004 llvm::Type::getInt8PtrTy(CGF.getLLVMContext(), DPT->getAddressSpace());
1005 DestPtr = CGF.Builder.CreateBitCast(DestPtr, DBP);
1006
1007 llvm::PointerType *SPT = SrcPtr.getType();
1008 llvm::Type *SBP =
1009 llvm::Type::getInt8PtrTy(CGF.getLLVMContext(), SPT->getAddressSpace());
1010 SrcPtr = CGF.Builder.CreateBitCast(SrcPtr, SBP);
1011
1012 CGF.Builder.CreateMemCpy(DestPtr, SrcPtr, Size.getQuantity());
1013 }
1014
addInitialField(FieldDecl * F)1015 void addInitialField(FieldDecl *F) {
1016 FirstField = F;
1017 LastField = F;
1018 FirstFieldOffset = RecLayout.getFieldOffset(F->getFieldIndex());
1019 LastFieldOffset = FirstFieldOffset;
1020 LastAddedFieldIndex = F->getFieldIndex();
1021 }
1022
addNextField(FieldDecl * F)1023 void addNextField(FieldDecl *F) {
1024 // For the most part, the following invariant will hold:
1025 // F->getFieldIndex() == LastAddedFieldIndex + 1
1026 // The one exception is that Sema won't add a copy-initializer for an
1027 // unnamed bitfield, which will show up here as a gap in the sequence.
1028 assert(F->getFieldIndex() >= LastAddedFieldIndex + 1 &&
1029 "Cannot aggregate fields out of order.");
1030 LastAddedFieldIndex = F->getFieldIndex();
1031
1032 // The 'first' and 'last' fields are chosen by offset, rather than field
1033 // index. This allows the code to support bitfields, as well as regular
1034 // fields.
1035 uint64_t FOffset = RecLayout.getFieldOffset(F->getFieldIndex());
1036 if (FOffset < FirstFieldOffset) {
1037 FirstField = F;
1038 FirstFieldOffset = FOffset;
1039 } else if (FOffset >= LastFieldOffset) {
1040 LastField = F;
1041 LastFieldOffset = FOffset;
1042 }
1043 }
1044
1045 const VarDecl *SrcRec;
1046 const ASTRecordLayout &RecLayout;
1047 FieldDecl *FirstField;
1048 FieldDecl *LastField;
1049 uint64_t FirstFieldOffset, LastFieldOffset;
1050 unsigned LastAddedFieldIndex;
1051 };
1052
1053 class ConstructorMemcpyizer : public FieldMemcpyizer {
1054 private:
1055 /// Get source argument for copy constructor. Returns null if not a copy
1056 /// constructor.
getTrivialCopySource(CodeGenFunction & CGF,const CXXConstructorDecl * CD,FunctionArgList & Args)1057 static const VarDecl *getTrivialCopySource(CodeGenFunction &CGF,
1058 const CXXConstructorDecl *CD,
1059 FunctionArgList &Args) {
1060 if (CD->isCopyOrMoveConstructor() && CD->isDefaulted())
1061 return Args[CGF.CGM.getCXXABI().getSrcArgforCopyCtor(CD, Args)];
1062 return nullptr;
1063 }
1064
1065 // Returns true if a CXXCtorInitializer represents a member initialization
1066 // that can be rolled into a memcpy.
isMemberInitMemcpyable(CXXCtorInitializer * MemberInit) const1067 bool isMemberInitMemcpyable(CXXCtorInitializer *MemberInit) const {
1068 if (!MemcpyableCtor)
1069 return false;
1070 FieldDecl *Field = MemberInit->getMember();
1071 assert(Field && "No field for member init.");
1072 QualType FieldType = Field->getType();
1073 CXXConstructExpr *CE = dyn_cast<CXXConstructExpr>(MemberInit->getInit());
1074
1075 // Bail out on non-memcpyable, not-trivially-copyable members.
1076 if (!(CE && isMemcpyEquivalentSpecialMember(CE->getConstructor())) &&
1077 !(FieldType.isTriviallyCopyableType(CGF.getContext()) ||
1078 FieldType->isReferenceType()))
1079 return false;
1080
1081 // Bail out on volatile fields.
1082 if (!isMemcpyableField(Field))
1083 return false;
1084
1085 // Otherwise we're good.
1086 return true;
1087 }
1088
1089 public:
ConstructorMemcpyizer(CodeGenFunction & CGF,const CXXConstructorDecl * CD,FunctionArgList & Args)1090 ConstructorMemcpyizer(CodeGenFunction &CGF, const CXXConstructorDecl *CD,
1091 FunctionArgList &Args)
1092 : FieldMemcpyizer(CGF, CD->getParent(), getTrivialCopySource(CGF, CD, Args)),
1093 ConstructorDecl(CD),
1094 MemcpyableCtor(CD->isDefaulted() &&
1095 CD->isCopyOrMoveConstructor() &&
1096 CGF.getLangOpts().getGC() == LangOptions::NonGC),
1097 Args(Args) { }
1098
addMemberInitializer(CXXCtorInitializer * MemberInit)1099 void addMemberInitializer(CXXCtorInitializer *MemberInit) {
1100 if (isMemberInitMemcpyable(MemberInit)) {
1101 AggregatedInits.push_back(MemberInit);
1102 addMemcpyableField(MemberInit->getMember());
1103 } else {
1104 emitAggregatedInits();
1105 EmitMemberInitializer(CGF, ConstructorDecl->getParent(), MemberInit,
1106 ConstructorDecl, Args);
1107 }
1108 }
1109
emitAggregatedInits()1110 void emitAggregatedInits() {
1111 if (AggregatedInits.size() <= 1) {
1112 // This memcpy is too small to be worthwhile. Fall back on default
1113 // codegen.
1114 if (!AggregatedInits.empty()) {
1115 CopyingValueRepresentation CVR(CGF);
1116 EmitMemberInitializer(CGF, ConstructorDecl->getParent(),
1117 AggregatedInits[0], ConstructorDecl, Args);
1118 AggregatedInits.clear();
1119 }
1120 reset();
1121 return;
1122 }
1123
1124 pushEHDestructors();
1125 emitMemcpy();
1126 AggregatedInits.clear();
1127 }
1128
pushEHDestructors()1129 void pushEHDestructors() {
1130 Address ThisPtr = CGF.LoadCXXThisAddress();
1131 QualType RecordTy = CGF.getContext().getTypeDeclType(ClassDecl);
1132 LValue LHS = CGF.MakeAddrLValue(ThisPtr, RecordTy);
1133
1134 for (unsigned i = 0; i < AggregatedInits.size(); ++i) {
1135 CXXCtorInitializer *MemberInit = AggregatedInits[i];
1136 QualType FieldType = MemberInit->getAnyMember()->getType();
1137 QualType::DestructionKind dtorKind = FieldType.isDestructedType();
1138 if (!CGF.needsEHCleanup(dtorKind))
1139 continue;
1140 LValue FieldLHS = LHS;
1141 EmitLValueForAnyFieldInitialization(CGF, MemberInit, FieldLHS);
1142 CGF.pushEHDestroy(dtorKind, FieldLHS.getAddress(CGF), FieldType);
1143 }
1144 }
1145
finish()1146 void finish() {
1147 emitAggregatedInits();
1148 }
1149
1150 private:
1151 const CXXConstructorDecl *ConstructorDecl;
1152 bool MemcpyableCtor;
1153 FunctionArgList &Args;
1154 SmallVector<CXXCtorInitializer*, 16> AggregatedInits;
1155 };
1156
1157 class AssignmentMemcpyizer : public FieldMemcpyizer {
1158 private:
1159 // Returns the memcpyable field copied by the given statement, if one
1160 // exists. Otherwise returns null.
getMemcpyableField(Stmt * S)1161 FieldDecl *getMemcpyableField(Stmt *S) {
1162 if (!AssignmentsMemcpyable)
1163 return nullptr;
1164 if (BinaryOperator *BO = dyn_cast<BinaryOperator>(S)) {
1165 // Recognise trivial assignments.
1166 if (BO->getOpcode() != BO_Assign)
1167 return nullptr;
1168 MemberExpr *ME = dyn_cast<MemberExpr>(BO->getLHS());
1169 if (!ME)
1170 return nullptr;
1171 FieldDecl *Field = dyn_cast<FieldDecl>(ME->getMemberDecl());
1172 if (!Field || !isMemcpyableField(Field))
1173 return nullptr;
1174 Stmt *RHS = BO->getRHS();
1175 if (ImplicitCastExpr *EC = dyn_cast<ImplicitCastExpr>(RHS))
1176 RHS = EC->getSubExpr();
1177 if (!RHS)
1178 return nullptr;
1179 if (MemberExpr *ME2 = dyn_cast<MemberExpr>(RHS)) {
1180 if (ME2->getMemberDecl() == Field)
1181 return Field;
1182 }
1183 return nullptr;
1184 } else if (CXXMemberCallExpr *MCE = dyn_cast<CXXMemberCallExpr>(S)) {
1185 CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(MCE->getCalleeDecl());
1186 if (!(MD && isMemcpyEquivalentSpecialMember(MD)))
1187 return nullptr;
1188 MemberExpr *IOA = dyn_cast<MemberExpr>(MCE->getImplicitObjectArgument());
1189 if (!IOA)
1190 return nullptr;
1191 FieldDecl *Field = dyn_cast<FieldDecl>(IOA->getMemberDecl());
1192 if (!Field || !isMemcpyableField(Field))
1193 return nullptr;
1194 MemberExpr *Arg0 = dyn_cast<MemberExpr>(MCE->getArg(0));
1195 if (!Arg0 || Field != dyn_cast<FieldDecl>(Arg0->getMemberDecl()))
1196 return nullptr;
1197 return Field;
1198 } else if (CallExpr *CE = dyn_cast<CallExpr>(S)) {
1199 FunctionDecl *FD = dyn_cast<FunctionDecl>(CE->getCalleeDecl());
1200 if (!FD || FD->getBuiltinID() != Builtin::BI__builtin_memcpy)
1201 return nullptr;
1202 Expr *DstPtr = CE->getArg(0);
1203 if (ImplicitCastExpr *DC = dyn_cast<ImplicitCastExpr>(DstPtr))
1204 DstPtr = DC->getSubExpr();
1205 UnaryOperator *DUO = dyn_cast<UnaryOperator>(DstPtr);
1206 if (!DUO || DUO->getOpcode() != UO_AddrOf)
1207 return nullptr;
1208 MemberExpr *ME = dyn_cast<MemberExpr>(DUO->getSubExpr());
1209 if (!ME)
1210 return nullptr;
1211 FieldDecl *Field = dyn_cast<FieldDecl>(ME->getMemberDecl());
1212 if (!Field || !isMemcpyableField(Field))
1213 return nullptr;
1214 Expr *SrcPtr = CE->getArg(1);
1215 if (ImplicitCastExpr *SC = dyn_cast<ImplicitCastExpr>(SrcPtr))
1216 SrcPtr = SC->getSubExpr();
1217 UnaryOperator *SUO = dyn_cast<UnaryOperator>(SrcPtr);
1218 if (!SUO || SUO->getOpcode() != UO_AddrOf)
1219 return nullptr;
1220 MemberExpr *ME2 = dyn_cast<MemberExpr>(SUO->getSubExpr());
1221 if (!ME2 || Field != dyn_cast<FieldDecl>(ME2->getMemberDecl()))
1222 return nullptr;
1223 return Field;
1224 }
1225
1226 return nullptr;
1227 }
1228
1229 bool AssignmentsMemcpyable;
1230 SmallVector<Stmt*, 16> AggregatedStmts;
1231
1232 public:
AssignmentMemcpyizer(CodeGenFunction & CGF,const CXXMethodDecl * AD,FunctionArgList & Args)1233 AssignmentMemcpyizer(CodeGenFunction &CGF, const CXXMethodDecl *AD,
1234 FunctionArgList &Args)
1235 : FieldMemcpyizer(CGF, AD->getParent(), Args[Args.size() - 1]),
1236 AssignmentsMemcpyable(CGF.getLangOpts().getGC() == LangOptions::NonGC) {
1237 assert(Args.size() == 2);
1238 }
1239
emitAssignment(Stmt * S)1240 void emitAssignment(Stmt *S) {
1241 FieldDecl *F = getMemcpyableField(S);
1242 if (F) {
1243 addMemcpyableField(F);
1244 AggregatedStmts.push_back(S);
1245 } else {
1246 emitAggregatedStmts();
1247 CGF.EmitStmt(S);
1248 }
1249 }
1250
emitAggregatedStmts()1251 void emitAggregatedStmts() {
1252 if (AggregatedStmts.size() <= 1) {
1253 if (!AggregatedStmts.empty()) {
1254 CopyingValueRepresentation CVR(CGF);
1255 CGF.EmitStmt(AggregatedStmts[0]);
1256 }
1257 reset();
1258 }
1259
1260 emitMemcpy();
1261 AggregatedStmts.clear();
1262 }
1263
finish()1264 void finish() {
1265 emitAggregatedStmts();
1266 }
1267 };
1268 } // end anonymous namespace
1269
isInitializerOfDynamicClass(const CXXCtorInitializer * BaseInit)1270 static bool isInitializerOfDynamicClass(const CXXCtorInitializer *BaseInit) {
1271 const Type *BaseType = BaseInit->getBaseClass();
1272 const auto *BaseClassDecl =
1273 cast<CXXRecordDecl>(BaseType->castAs<RecordType>()->getDecl());
1274 return BaseClassDecl->isDynamicClass();
1275 }
1276
1277 /// EmitCtorPrologue - This routine generates necessary code to initialize
1278 /// base classes and non-static data members belonging to this constructor.
EmitCtorPrologue(const CXXConstructorDecl * CD,CXXCtorType CtorType,FunctionArgList & Args)1279 void CodeGenFunction::EmitCtorPrologue(const CXXConstructorDecl *CD,
1280 CXXCtorType CtorType,
1281 FunctionArgList &Args) {
1282 if (CD->isDelegatingConstructor())
1283 return EmitDelegatingCXXConstructorCall(CD, Args);
1284
1285 const CXXRecordDecl *ClassDecl = CD->getParent();
1286
1287 CXXConstructorDecl::init_const_iterator B = CD->init_begin(),
1288 E = CD->init_end();
1289
1290 // Virtual base initializers first, if any. They aren't needed if:
1291 // - This is a base ctor variant
1292 // - There are no vbases
1293 // - The class is abstract, so a complete object of it cannot be constructed
1294 //
1295 // The check for an abstract class is necessary because sema may not have
1296 // marked virtual base destructors referenced.
1297 bool ConstructVBases = CtorType != Ctor_Base &&
1298 ClassDecl->getNumVBases() != 0 &&
1299 !ClassDecl->isAbstract();
1300
1301 // In the Microsoft C++ ABI, there are no constructor variants. Instead, the
1302 // constructor of a class with virtual bases takes an additional parameter to
1303 // conditionally construct the virtual bases. Emit that check here.
1304 llvm::BasicBlock *BaseCtorContinueBB = nullptr;
1305 if (ConstructVBases &&
1306 !CGM.getTarget().getCXXABI().hasConstructorVariants()) {
1307 BaseCtorContinueBB =
1308 CGM.getCXXABI().EmitCtorCompleteObjectHandler(*this, ClassDecl);
1309 assert(BaseCtorContinueBB);
1310 }
1311
1312 llvm::Value *const OldThis = CXXThisValue;
1313 for (; B != E && (*B)->isBaseInitializer() && (*B)->isBaseVirtual(); B++) {
1314 if (!ConstructVBases)
1315 continue;
1316 if (CGM.getCodeGenOpts().StrictVTablePointers &&
1317 CGM.getCodeGenOpts().OptimizationLevel > 0 &&
1318 isInitializerOfDynamicClass(*B))
1319 CXXThisValue = Builder.CreateLaunderInvariantGroup(LoadCXXThis());
1320 EmitBaseInitializer(*this, ClassDecl, *B);
1321 }
1322
1323 if (BaseCtorContinueBB) {
1324 // Complete object handler should continue to the remaining initializers.
1325 Builder.CreateBr(BaseCtorContinueBB);
1326 EmitBlock(BaseCtorContinueBB);
1327 }
1328
1329 // Then, non-virtual base initializers.
1330 for (; B != E && (*B)->isBaseInitializer(); B++) {
1331 assert(!(*B)->isBaseVirtual());
1332
1333 if (CGM.getCodeGenOpts().StrictVTablePointers &&
1334 CGM.getCodeGenOpts().OptimizationLevel > 0 &&
1335 isInitializerOfDynamicClass(*B))
1336 CXXThisValue = Builder.CreateLaunderInvariantGroup(LoadCXXThis());
1337 EmitBaseInitializer(*this, ClassDecl, *B);
1338 }
1339
1340 CXXThisValue = OldThis;
1341
1342 InitializeVTablePointers(ClassDecl);
1343
1344 // And finally, initialize class members.
1345 FieldConstructionScope FCS(*this, LoadCXXThisAddress());
1346 ConstructorMemcpyizer CM(*this, CD, Args);
1347 for (; B != E; B++) {
1348 CXXCtorInitializer *Member = (*B);
1349 assert(!Member->isBaseInitializer());
1350 assert(Member->isAnyMemberInitializer() &&
1351 "Delegating initializer on non-delegating constructor");
1352 CM.addMemberInitializer(Member);
1353 }
1354 CM.finish();
1355 }
1356
1357 static bool
1358 FieldHasTrivialDestructorBody(ASTContext &Context, const FieldDecl *Field);
1359
1360 static bool
HasTrivialDestructorBody(ASTContext & Context,const CXXRecordDecl * BaseClassDecl,const CXXRecordDecl * MostDerivedClassDecl)1361 HasTrivialDestructorBody(ASTContext &Context,
1362 const CXXRecordDecl *BaseClassDecl,
1363 const CXXRecordDecl *MostDerivedClassDecl)
1364 {
1365 // If the destructor is trivial we don't have to check anything else.
1366 if (BaseClassDecl->hasTrivialDestructor())
1367 return true;
1368
1369 if (!BaseClassDecl->getDestructor()->hasTrivialBody())
1370 return false;
1371
1372 // Check fields.
1373 for (const auto *Field : BaseClassDecl->fields())
1374 if (!FieldHasTrivialDestructorBody(Context, Field))
1375 return false;
1376
1377 // Check non-virtual bases.
1378 for (const auto &I : BaseClassDecl->bases()) {
1379 if (I.isVirtual())
1380 continue;
1381
1382 const CXXRecordDecl *NonVirtualBase =
1383 cast<CXXRecordDecl>(I.getType()->castAs<RecordType>()->getDecl());
1384 if (!HasTrivialDestructorBody(Context, NonVirtualBase,
1385 MostDerivedClassDecl))
1386 return false;
1387 }
1388
1389 if (BaseClassDecl == MostDerivedClassDecl) {
1390 // Check virtual bases.
1391 for (const auto &I : BaseClassDecl->vbases()) {
1392 const CXXRecordDecl *VirtualBase =
1393 cast<CXXRecordDecl>(I.getType()->castAs<RecordType>()->getDecl());
1394 if (!HasTrivialDestructorBody(Context, VirtualBase,
1395 MostDerivedClassDecl))
1396 return false;
1397 }
1398 }
1399
1400 return true;
1401 }
1402
1403 static bool
FieldHasTrivialDestructorBody(ASTContext & Context,const FieldDecl * Field)1404 FieldHasTrivialDestructorBody(ASTContext &Context,
1405 const FieldDecl *Field)
1406 {
1407 QualType FieldBaseElementType = Context.getBaseElementType(Field->getType());
1408
1409 const RecordType *RT = FieldBaseElementType->getAs<RecordType>();
1410 if (!RT)
1411 return true;
1412
1413 CXXRecordDecl *FieldClassDecl = cast<CXXRecordDecl>(RT->getDecl());
1414
1415 // The destructor for an implicit anonymous union member is never invoked.
1416 if (FieldClassDecl->isUnion() && FieldClassDecl->isAnonymousStructOrUnion())
1417 return false;
1418
1419 return HasTrivialDestructorBody(Context, FieldClassDecl, FieldClassDecl);
1420 }
1421
1422 /// CanSkipVTablePointerInitialization - Check whether we need to initialize
1423 /// any vtable pointers before calling this destructor.
CanSkipVTablePointerInitialization(CodeGenFunction & CGF,const CXXDestructorDecl * Dtor)1424 static bool CanSkipVTablePointerInitialization(CodeGenFunction &CGF,
1425 const CXXDestructorDecl *Dtor) {
1426 const CXXRecordDecl *ClassDecl = Dtor->getParent();
1427 if (!ClassDecl->isDynamicClass())
1428 return true;
1429
1430 if (!Dtor->hasTrivialBody())
1431 return false;
1432
1433 // Check the fields.
1434 for (const auto *Field : ClassDecl->fields())
1435 if (!FieldHasTrivialDestructorBody(CGF.getContext(), Field))
1436 return false;
1437
1438 return true;
1439 }
1440
1441 /// EmitDestructorBody - Emits the body of the current destructor.
EmitDestructorBody(FunctionArgList & Args)1442 void CodeGenFunction::EmitDestructorBody(FunctionArgList &Args) {
1443 const CXXDestructorDecl *Dtor = cast<CXXDestructorDecl>(CurGD.getDecl());
1444 CXXDtorType DtorType = CurGD.getDtorType();
1445
1446 // For an abstract class, non-base destructors are never used (and can't
1447 // be emitted in general, because vbase dtors may not have been validated
1448 // by Sema), but the Itanium ABI doesn't make them optional and Clang may
1449 // in fact emit references to them from other compilations, so emit them
1450 // as functions containing a trap instruction.
1451 if (DtorType != Dtor_Base && Dtor->getParent()->isAbstract()) {
1452 llvm::CallInst *TrapCall = EmitTrapCall(llvm::Intrinsic::trap);
1453 TrapCall->setDoesNotReturn();
1454 TrapCall->setDoesNotThrow();
1455 Builder.CreateUnreachable();
1456 Builder.ClearInsertionPoint();
1457 return;
1458 }
1459
1460 Stmt *Body = Dtor->getBody();
1461 if (Body)
1462 incrementProfileCounter(Body);
1463
1464 // The call to operator delete in a deleting destructor happens
1465 // outside of the function-try-block, which means it's always
1466 // possible to delegate the destructor body to the complete
1467 // destructor. Do so.
1468 if (DtorType == Dtor_Deleting) {
1469 RunCleanupsScope DtorEpilogue(*this);
1470 EnterDtorCleanups(Dtor, Dtor_Deleting);
1471 if (HaveInsertPoint()) {
1472 QualType ThisTy = Dtor->getThisObjectType();
1473 EmitCXXDestructorCall(Dtor, Dtor_Complete, /*ForVirtualBase=*/false,
1474 /*Delegating=*/false, LoadCXXThisAddress(), ThisTy);
1475 }
1476 return;
1477 }
1478
1479 // If the body is a function-try-block, enter the try before
1480 // anything else.
1481 bool isTryBody = (Body && isa<CXXTryStmt>(Body));
1482 if (isTryBody)
1483 EnterCXXTryStmt(*cast<CXXTryStmt>(Body), true);
1484 EmitAsanPrologueOrEpilogue(false);
1485
1486 // Enter the epilogue cleanups.
1487 RunCleanupsScope DtorEpilogue(*this);
1488
1489 // If this is the complete variant, just invoke the base variant;
1490 // the epilogue will destruct the virtual bases. But we can't do
1491 // this optimization if the body is a function-try-block, because
1492 // we'd introduce *two* handler blocks. In the Microsoft ABI, we
1493 // always delegate because we might not have a definition in this TU.
1494 switch (DtorType) {
1495 case Dtor_Comdat: llvm_unreachable("not expecting a COMDAT");
1496 case Dtor_Deleting: llvm_unreachable("already handled deleting case");
1497
1498 case Dtor_Complete:
1499 assert((Body || getTarget().getCXXABI().isMicrosoft()) &&
1500 "can't emit a dtor without a body for non-Microsoft ABIs");
1501
1502 // Enter the cleanup scopes for virtual bases.
1503 EnterDtorCleanups(Dtor, Dtor_Complete);
1504
1505 if (!isTryBody) {
1506 QualType ThisTy = Dtor->getThisObjectType();
1507 EmitCXXDestructorCall(Dtor, Dtor_Base, /*ForVirtualBase=*/false,
1508 /*Delegating=*/false, LoadCXXThisAddress(), ThisTy);
1509 break;
1510 }
1511
1512 // Fallthrough: act like we're in the base variant.
1513 LLVM_FALLTHROUGH;
1514
1515 case Dtor_Base:
1516 assert(Body);
1517
1518 // Enter the cleanup scopes for fields and non-virtual bases.
1519 EnterDtorCleanups(Dtor, Dtor_Base);
1520
1521 // Initialize the vtable pointers before entering the body.
1522 if (!CanSkipVTablePointerInitialization(*this, Dtor)) {
1523 // Insert the llvm.launder.invariant.group intrinsic before initializing
1524 // the vptrs to cancel any previous assumptions we might have made.
1525 if (CGM.getCodeGenOpts().StrictVTablePointers &&
1526 CGM.getCodeGenOpts().OptimizationLevel > 0)
1527 CXXThisValue = Builder.CreateLaunderInvariantGroup(LoadCXXThis());
1528 InitializeVTablePointers(Dtor->getParent());
1529 }
1530
1531 if (isTryBody)
1532 EmitStmt(cast<CXXTryStmt>(Body)->getTryBlock());
1533 else if (Body)
1534 EmitStmt(Body);
1535 else {
1536 assert(Dtor->isImplicit() && "bodyless dtor not implicit");
1537 // nothing to do besides what's in the epilogue
1538 }
1539 // -fapple-kext must inline any call to this dtor into
1540 // the caller's body.
1541 if (getLangOpts().AppleKext)
1542 CurFn->addFnAttr(llvm::Attribute::AlwaysInline);
1543
1544 break;
1545 }
1546
1547 // Jump out through the epilogue cleanups.
1548 DtorEpilogue.ForceCleanup();
1549
1550 // Exit the try if applicable.
1551 if (isTryBody)
1552 ExitCXXTryStmt(*cast<CXXTryStmt>(Body), true);
1553 }
1554
emitImplicitAssignmentOperatorBody(FunctionArgList & Args)1555 void CodeGenFunction::emitImplicitAssignmentOperatorBody(FunctionArgList &Args) {
1556 const CXXMethodDecl *AssignOp = cast<CXXMethodDecl>(CurGD.getDecl());
1557 const Stmt *RootS = AssignOp->getBody();
1558 assert(isa<CompoundStmt>(RootS) &&
1559 "Body of an implicit assignment operator should be compound stmt.");
1560 const CompoundStmt *RootCS = cast<CompoundStmt>(RootS);
1561
1562 LexicalScope Scope(*this, RootCS->getSourceRange());
1563
1564 incrementProfileCounter(RootCS);
1565 AssignmentMemcpyizer AM(*this, AssignOp, Args);
1566 for (auto *I : RootCS->body())
1567 AM.emitAssignment(I);
1568 AM.finish();
1569 }
1570
1571 namespace {
LoadThisForDtorDelete(CodeGenFunction & CGF,const CXXDestructorDecl * DD)1572 llvm::Value *LoadThisForDtorDelete(CodeGenFunction &CGF,
1573 const CXXDestructorDecl *DD) {
1574 if (Expr *ThisArg = DD->getOperatorDeleteThisArg())
1575 return CGF.EmitScalarExpr(ThisArg);
1576 return CGF.LoadCXXThis();
1577 }
1578
1579 /// Call the operator delete associated with the current destructor.
1580 struct CallDtorDelete final : EHScopeStack::Cleanup {
CallDtorDelete__anon463df5f00411::CallDtorDelete1581 CallDtorDelete() {}
1582
Emit__anon463df5f00411::CallDtorDelete1583 void Emit(CodeGenFunction &CGF, Flags flags) override {
1584 const CXXDestructorDecl *Dtor = cast<CXXDestructorDecl>(CGF.CurCodeDecl);
1585 const CXXRecordDecl *ClassDecl = Dtor->getParent();
1586 CGF.EmitDeleteCall(Dtor->getOperatorDelete(),
1587 LoadThisForDtorDelete(CGF, Dtor),
1588 CGF.getContext().getTagDeclType(ClassDecl));
1589 }
1590 };
1591
EmitConditionalDtorDeleteCall(CodeGenFunction & CGF,llvm::Value * ShouldDeleteCondition,bool ReturnAfterDelete)1592 void EmitConditionalDtorDeleteCall(CodeGenFunction &CGF,
1593 llvm::Value *ShouldDeleteCondition,
1594 bool ReturnAfterDelete) {
1595 llvm::BasicBlock *callDeleteBB = CGF.createBasicBlock("dtor.call_delete");
1596 llvm::BasicBlock *continueBB = CGF.createBasicBlock("dtor.continue");
1597 llvm::Value *ShouldCallDelete
1598 = CGF.Builder.CreateIsNull(ShouldDeleteCondition);
1599 CGF.Builder.CreateCondBr(ShouldCallDelete, continueBB, callDeleteBB);
1600
1601 CGF.EmitBlock(callDeleteBB);
1602 const CXXDestructorDecl *Dtor = cast<CXXDestructorDecl>(CGF.CurCodeDecl);
1603 const CXXRecordDecl *ClassDecl = Dtor->getParent();
1604 CGF.EmitDeleteCall(Dtor->getOperatorDelete(),
1605 LoadThisForDtorDelete(CGF, Dtor),
1606 CGF.getContext().getTagDeclType(ClassDecl));
1607 assert(Dtor->getOperatorDelete()->isDestroyingOperatorDelete() ==
1608 ReturnAfterDelete &&
1609 "unexpected value for ReturnAfterDelete");
1610 if (ReturnAfterDelete)
1611 CGF.EmitBranchThroughCleanup(CGF.ReturnBlock);
1612 else
1613 CGF.Builder.CreateBr(continueBB);
1614
1615 CGF.EmitBlock(continueBB);
1616 }
1617
1618 struct CallDtorDeleteConditional final : EHScopeStack::Cleanup {
1619 llvm::Value *ShouldDeleteCondition;
1620
1621 public:
CallDtorDeleteConditional__anon463df5f00411::CallDtorDeleteConditional1622 CallDtorDeleteConditional(llvm::Value *ShouldDeleteCondition)
1623 : ShouldDeleteCondition(ShouldDeleteCondition) {
1624 assert(ShouldDeleteCondition != nullptr);
1625 }
1626
Emit__anon463df5f00411::CallDtorDeleteConditional1627 void Emit(CodeGenFunction &CGF, Flags flags) override {
1628 EmitConditionalDtorDeleteCall(CGF, ShouldDeleteCondition,
1629 /*ReturnAfterDelete*/false);
1630 }
1631 };
1632
1633 class DestroyField final : public EHScopeStack::Cleanup {
1634 const FieldDecl *field;
1635 CodeGenFunction::Destroyer *destroyer;
1636 bool useEHCleanupForArray;
1637
1638 public:
DestroyField(const FieldDecl * field,CodeGenFunction::Destroyer * destroyer,bool useEHCleanupForArray)1639 DestroyField(const FieldDecl *field, CodeGenFunction::Destroyer *destroyer,
1640 bool useEHCleanupForArray)
1641 : field(field), destroyer(destroyer),
1642 useEHCleanupForArray(useEHCleanupForArray) {}
1643
Emit(CodeGenFunction & CGF,Flags flags)1644 void Emit(CodeGenFunction &CGF, Flags flags) override {
1645 // Find the address of the field.
1646 Address thisValue = CGF.LoadCXXThisAddress();
1647 QualType RecordTy = CGF.getContext().getTagDeclType(field->getParent());
1648 LValue ThisLV = CGF.MakeAddrLValue(thisValue, RecordTy);
1649 LValue LV = CGF.EmitLValueForField(ThisLV, field);
1650 assert(LV.isSimple());
1651
1652 CGF.emitDestroy(LV.getAddress(CGF), field->getType(), destroyer,
1653 flags.isForNormalCleanup() && useEHCleanupForArray);
1654 }
1655 };
1656
EmitSanitizerDtorCallback(CodeGenFunction & CGF,llvm::Value * Ptr,CharUnits::QuantityType PoisonSize)1657 static void EmitSanitizerDtorCallback(CodeGenFunction &CGF, llvm::Value *Ptr,
1658 CharUnits::QuantityType PoisonSize) {
1659 CodeGenFunction::SanitizerScope SanScope(&CGF);
1660 // Pass in void pointer and size of region as arguments to runtime
1661 // function
1662 llvm::Value *Args[] = {CGF.Builder.CreateBitCast(Ptr, CGF.VoidPtrTy),
1663 llvm::ConstantInt::get(CGF.SizeTy, PoisonSize)};
1664
1665 llvm::Type *ArgTypes[] = {CGF.VoidPtrTy, CGF.SizeTy};
1666
1667 llvm::FunctionType *FnType =
1668 llvm::FunctionType::get(CGF.VoidTy, ArgTypes, false);
1669 llvm::FunctionCallee Fn =
1670 CGF.CGM.CreateRuntimeFunction(FnType, "__sanitizer_dtor_callback");
1671 CGF.EmitNounwindRuntimeCall(Fn, Args);
1672 }
1673
1674 class SanitizeDtorMembers final : public EHScopeStack::Cleanup {
1675 const CXXDestructorDecl *Dtor;
1676
1677 public:
SanitizeDtorMembers(const CXXDestructorDecl * Dtor)1678 SanitizeDtorMembers(const CXXDestructorDecl *Dtor) : Dtor(Dtor) {}
1679
1680 // Generate function call for handling object poisoning.
1681 // Disables tail call elimination, to prevent the current stack frame
1682 // from disappearing from the stack trace.
Emit(CodeGenFunction & CGF,Flags flags)1683 void Emit(CodeGenFunction &CGF, Flags flags) override {
1684 const ASTRecordLayout &Layout =
1685 CGF.getContext().getASTRecordLayout(Dtor->getParent());
1686
1687 // Nothing to poison.
1688 if (Layout.getFieldCount() == 0)
1689 return;
1690
1691 // Prevent the current stack frame from disappearing from the stack trace.
1692 CGF.CurFn->addFnAttr("disable-tail-calls", "true");
1693
1694 // Construct pointer to region to begin poisoning, and calculate poison
1695 // size, so that only members declared in this class are poisoned.
1696 ASTContext &Context = CGF.getContext();
1697 unsigned fieldIndex = 0;
1698 int startIndex = -1;
1699 // RecordDecl::field_iterator Field;
1700 for (const FieldDecl *Field : Dtor->getParent()->fields()) {
1701 // Poison field if it is trivial
1702 if (FieldHasTrivialDestructorBody(Context, Field)) {
1703 // Start sanitizing at this field
1704 if (startIndex < 0)
1705 startIndex = fieldIndex;
1706
1707 // Currently on the last field, and it must be poisoned with the
1708 // current block.
1709 if (fieldIndex == Layout.getFieldCount() - 1) {
1710 PoisonMembers(CGF, startIndex, Layout.getFieldCount());
1711 }
1712 } else if (startIndex >= 0) {
1713 // No longer within a block of memory to poison, so poison the block
1714 PoisonMembers(CGF, startIndex, fieldIndex);
1715 // Re-set the start index
1716 startIndex = -1;
1717 }
1718 fieldIndex += 1;
1719 }
1720 }
1721
1722 private:
1723 /// \param layoutStartOffset index of the ASTRecordLayout field to
1724 /// start poisoning (inclusive)
1725 /// \param layoutEndOffset index of the ASTRecordLayout field to
1726 /// end poisoning (exclusive)
PoisonMembers(CodeGenFunction & CGF,unsigned layoutStartOffset,unsigned layoutEndOffset)1727 void PoisonMembers(CodeGenFunction &CGF, unsigned layoutStartOffset,
1728 unsigned layoutEndOffset) {
1729 ASTContext &Context = CGF.getContext();
1730 const ASTRecordLayout &Layout =
1731 Context.getASTRecordLayout(Dtor->getParent());
1732
1733 llvm::ConstantInt *OffsetSizePtr = llvm::ConstantInt::get(
1734 CGF.SizeTy,
1735 Context.toCharUnitsFromBits(Layout.getFieldOffset(layoutStartOffset))
1736 .getQuantity());
1737
1738 llvm::Value *OffsetPtr = CGF.Builder.CreateGEP(
1739 CGF.Builder.CreateBitCast(CGF.LoadCXXThis(), CGF.Int8PtrTy),
1740 OffsetSizePtr);
1741
1742 CharUnits::QuantityType PoisonSize;
1743 if (layoutEndOffset >= Layout.getFieldCount()) {
1744 PoisonSize = Layout.getNonVirtualSize().getQuantity() -
1745 Context.toCharUnitsFromBits(
1746 Layout.getFieldOffset(layoutStartOffset))
1747 .getQuantity();
1748 } else {
1749 PoisonSize = Context.toCharUnitsFromBits(
1750 Layout.getFieldOffset(layoutEndOffset) -
1751 Layout.getFieldOffset(layoutStartOffset))
1752 .getQuantity();
1753 }
1754
1755 if (PoisonSize == 0)
1756 return;
1757
1758 EmitSanitizerDtorCallback(CGF, OffsetPtr, PoisonSize);
1759 }
1760 };
1761
1762 class SanitizeDtorVTable final : public EHScopeStack::Cleanup {
1763 const CXXDestructorDecl *Dtor;
1764
1765 public:
SanitizeDtorVTable(const CXXDestructorDecl * Dtor)1766 SanitizeDtorVTable(const CXXDestructorDecl *Dtor) : Dtor(Dtor) {}
1767
1768 // Generate function call for handling vtable pointer poisoning.
Emit(CodeGenFunction & CGF,Flags flags)1769 void Emit(CodeGenFunction &CGF, Flags flags) override {
1770 assert(Dtor->getParent()->isDynamicClass());
1771 (void)Dtor;
1772 ASTContext &Context = CGF.getContext();
1773 // Poison vtable and vtable ptr if they exist for this class.
1774 llvm::Value *VTablePtr = CGF.LoadCXXThis();
1775
1776 CharUnits::QuantityType PoisonSize =
1777 Context.toCharUnitsFromBits(CGF.PointerWidthInBits).getQuantity();
1778 // Pass in void pointer and size of region as arguments to runtime
1779 // function
1780 EmitSanitizerDtorCallback(CGF, VTablePtr, PoisonSize);
1781 }
1782 };
1783 } // end anonymous namespace
1784
1785 /// Emit all code that comes at the end of class's
1786 /// destructor. This is to call destructors on members and base classes
1787 /// in reverse order of their construction.
1788 ///
1789 /// For a deleting destructor, this also handles the case where a destroying
1790 /// operator delete completely overrides the definition.
EnterDtorCleanups(const CXXDestructorDecl * DD,CXXDtorType DtorType)1791 void CodeGenFunction::EnterDtorCleanups(const CXXDestructorDecl *DD,
1792 CXXDtorType DtorType) {
1793 assert((!DD->isTrivial() || DD->hasAttr<DLLExportAttr>()) &&
1794 "Should not emit dtor epilogue for non-exported trivial dtor!");
1795
1796 // The deleting-destructor phase just needs to call the appropriate
1797 // operator delete that Sema picked up.
1798 if (DtorType == Dtor_Deleting) {
1799 assert(DD->getOperatorDelete() &&
1800 "operator delete missing - EnterDtorCleanups");
1801 if (CXXStructorImplicitParamValue) {
1802 // If there is an implicit param to the deleting dtor, it's a boolean
1803 // telling whether this is a deleting destructor.
1804 if (DD->getOperatorDelete()->isDestroyingOperatorDelete())
1805 EmitConditionalDtorDeleteCall(*this, CXXStructorImplicitParamValue,
1806 /*ReturnAfterDelete*/true);
1807 else
1808 EHStack.pushCleanup<CallDtorDeleteConditional>(
1809 NormalAndEHCleanup, CXXStructorImplicitParamValue);
1810 } else {
1811 if (DD->getOperatorDelete()->isDestroyingOperatorDelete()) {
1812 const CXXRecordDecl *ClassDecl = DD->getParent();
1813 EmitDeleteCall(DD->getOperatorDelete(),
1814 LoadThisForDtorDelete(*this, DD),
1815 getContext().getTagDeclType(ClassDecl));
1816 EmitBranchThroughCleanup(ReturnBlock);
1817 } else {
1818 EHStack.pushCleanup<CallDtorDelete>(NormalAndEHCleanup);
1819 }
1820 }
1821 return;
1822 }
1823
1824 const CXXRecordDecl *ClassDecl = DD->getParent();
1825
1826 // Unions have no bases and do not call field destructors.
1827 if (ClassDecl->isUnion())
1828 return;
1829
1830 // The complete-destructor phase just destructs all the virtual bases.
1831 if (DtorType == Dtor_Complete) {
1832 // Poison the vtable pointer such that access after the base
1833 // and member destructors are invoked is invalid.
1834 if (CGM.getCodeGenOpts().SanitizeMemoryUseAfterDtor &&
1835 SanOpts.has(SanitizerKind::Memory) && ClassDecl->getNumVBases() &&
1836 ClassDecl->isPolymorphic())
1837 EHStack.pushCleanup<SanitizeDtorVTable>(NormalAndEHCleanup, DD);
1838
1839 // We push them in the forward order so that they'll be popped in
1840 // the reverse order.
1841 for (const auto &Base : ClassDecl->vbases()) {
1842 auto *BaseClassDecl =
1843 cast<CXXRecordDecl>(Base.getType()->castAs<RecordType>()->getDecl());
1844
1845 // Ignore trivial destructors.
1846 if (BaseClassDecl->hasTrivialDestructor())
1847 continue;
1848
1849 EHStack.pushCleanup<CallBaseDtor>(NormalAndEHCleanup,
1850 BaseClassDecl,
1851 /*BaseIsVirtual*/ true);
1852 }
1853
1854 return;
1855 }
1856
1857 assert(DtorType == Dtor_Base);
1858 // Poison the vtable pointer if it has no virtual bases, but inherits
1859 // virtual functions.
1860 if (CGM.getCodeGenOpts().SanitizeMemoryUseAfterDtor &&
1861 SanOpts.has(SanitizerKind::Memory) && !ClassDecl->getNumVBases() &&
1862 ClassDecl->isPolymorphic())
1863 EHStack.pushCleanup<SanitizeDtorVTable>(NormalAndEHCleanup, DD);
1864
1865 // Destroy non-virtual bases.
1866 for (const auto &Base : ClassDecl->bases()) {
1867 // Ignore virtual bases.
1868 if (Base.isVirtual())
1869 continue;
1870
1871 CXXRecordDecl *BaseClassDecl = Base.getType()->getAsCXXRecordDecl();
1872
1873 // Ignore trivial destructors.
1874 if (BaseClassDecl->hasTrivialDestructor())
1875 continue;
1876
1877 EHStack.pushCleanup<CallBaseDtor>(NormalAndEHCleanup,
1878 BaseClassDecl,
1879 /*BaseIsVirtual*/ false);
1880 }
1881
1882 // Poison fields such that access after their destructors are
1883 // invoked, and before the base class destructor runs, is invalid.
1884 if (CGM.getCodeGenOpts().SanitizeMemoryUseAfterDtor &&
1885 SanOpts.has(SanitizerKind::Memory))
1886 EHStack.pushCleanup<SanitizeDtorMembers>(NormalAndEHCleanup, DD);
1887
1888 // Destroy direct fields.
1889 for (const auto *Field : ClassDecl->fields()) {
1890 QualType type = Field->getType();
1891 QualType::DestructionKind dtorKind = type.isDestructedType();
1892 if (!dtorKind) continue;
1893
1894 // Anonymous union members do not have their destructors called.
1895 const RecordType *RT = type->getAsUnionType();
1896 if (RT && RT->getDecl()->isAnonymousStructOrUnion()) continue;
1897
1898 CleanupKind cleanupKind = getCleanupKind(dtorKind);
1899 EHStack.pushCleanup<DestroyField>(cleanupKind, Field,
1900 getDestroyer(dtorKind),
1901 cleanupKind & EHCleanup);
1902 }
1903 }
1904
1905 /// EmitCXXAggrConstructorCall - Emit a loop to call a particular
1906 /// constructor for each of several members of an array.
1907 ///
1908 /// \param ctor the constructor to call for each element
1909 /// \param arrayType the type of the array to initialize
1910 /// \param arrayBegin an arrayType*
1911 /// \param zeroInitialize true if each element should be
1912 /// zero-initialized before it is constructed
EmitCXXAggrConstructorCall(const CXXConstructorDecl * ctor,const ArrayType * arrayType,Address arrayBegin,const CXXConstructExpr * E,bool NewPointerIsChecked,bool zeroInitialize)1913 void CodeGenFunction::EmitCXXAggrConstructorCall(
1914 const CXXConstructorDecl *ctor, const ArrayType *arrayType,
1915 Address arrayBegin, const CXXConstructExpr *E, bool NewPointerIsChecked,
1916 bool zeroInitialize) {
1917 QualType elementType;
1918 llvm::Value *numElements =
1919 emitArrayLength(arrayType, elementType, arrayBegin);
1920
1921 EmitCXXAggrConstructorCall(ctor, numElements, arrayBegin, E,
1922 NewPointerIsChecked, zeroInitialize);
1923 }
1924
1925 /// EmitCXXAggrConstructorCall - Emit a loop to call a particular
1926 /// constructor for each of several members of an array.
1927 ///
1928 /// \param ctor the constructor to call for each element
1929 /// \param numElements the number of elements in the array;
1930 /// may be zero
1931 /// \param arrayBase a T*, where T is the type constructed by ctor
1932 /// \param zeroInitialize true if each element should be
1933 /// zero-initialized before it is constructed
EmitCXXAggrConstructorCall(const CXXConstructorDecl * ctor,llvm::Value * numElements,Address arrayBase,const CXXConstructExpr * E,bool NewPointerIsChecked,bool zeroInitialize)1934 void CodeGenFunction::EmitCXXAggrConstructorCall(const CXXConstructorDecl *ctor,
1935 llvm::Value *numElements,
1936 Address arrayBase,
1937 const CXXConstructExpr *E,
1938 bool NewPointerIsChecked,
1939 bool zeroInitialize) {
1940 // It's legal for numElements to be zero. This can happen both
1941 // dynamically, because x can be zero in 'new A[x]', and statically,
1942 // because of GCC extensions that permit zero-length arrays. There
1943 // are probably legitimate places where we could assume that this
1944 // doesn't happen, but it's not clear that it's worth it.
1945 llvm::BranchInst *zeroCheckBranch = nullptr;
1946
1947 // Optimize for a constant count.
1948 llvm::ConstantInt *constantCount
1949 = dyn_cast<llvm::ConstantInt>(numElements);
1950 if (constantCount) {
1951 // Just skip out if the constant count is zero.
1952 if (constantCount->isZero()) return;
1953
1954 // Otherwise, emit the check.
1955 } else {
1956 llvm::BasicBlock *loopBB = createBasicBlock("new.ctorloop");
1957 llvm::Value *iszero = Builder.CreateIsNull(numElements, "isempty");
1958 zeroCheckBranch = Builder.CreateCondBr(iszero, loopBB, loopBB);
1959 EmitBlock(loopBB);
1960 }
1961
1962 // Find the end of the array.
1963 llvm::Value *arrayBegin = arrayBase.getPointer();
1964 llvm::Value *arrayEnd = Builder.CreateInBoundsGEP(arrayBegin, numElements,
1965 "arrayctor.end");
1966
1967 // Enter the loop, setting up a phi for the current location to initialize.
1968 llvm::BasicBlock *entryBB = Builder.GetInsertBlock();
1969 llvm::BasicBlock *loopBB = createBasicBlock("arrayctor.loop");
1970 EmitBlock(loopBB);
1971 llvm::PHINode *cur = Builder.CreatePHI(arrayBegin->getType(), 2,
1972 "arrayctor.cur");
1973 cur->addIncoming(arrayBegin, entryBB);
1974
1975 // Inside the loop body, emit the constructor call on the array element.
1976
1977 // The alignment of the base, adjusted by the size of a single element,
1978 // provides a conservative estimate of the alignment of every element.
1979 // (This assumes we never start tracking offsetted alignments.)
1980 //
1981 // Note that these are complete objects and so we don't need to
1982 // use the non-virtual size or alignment.
1983 QualType type = getContext().getTypeDeclType(ctor->getParent());
1984 CharUnits eltAlignment =
1985 arrayBase.getAlignment()
1986 .alignmentOfArrayElement(getContext().getTypeSizeInChars(type));
1987 Address curAddr = Address(cur, eltAlignment);
1988
1989 // Zero initialize the storage, if requested.
1990 if (zeroInitialize)
1991 EmitNullInitialization(curAddr, type);
1992
1993 // C++ [class.temporary]p4:
1994 // There are two contexts in which temporaries are destroyed at a different
1995 // point than the end of the full-expression. The first context is when a
1996 // default constructor is called to initialize an element of an array.
1997 // If the constructor has one or more default arguments, the destruction of
1998 // every temporary created in a default argument expression is sequenced
1999 // before the construction of the next array element, if any.
2000
2001 {
2002 RunCleanupsScope Scope(*this);
2003
2004 // Evaluate the constructor and its arguments in a regular
2005 // partial-destroy cleanup.
2006 if (getLangOpts().Exceptions &&
2007 !ctor->getParent()->hasTrivialDestructor()) {
2008 Destroyer *destroyer = destroyCXXObject;
2009 pushRegularPartialArrayCleanup(arrayBegin, cur, type, eltAlignment,
2010 *destroyer);
2011 }
2012 auto currAVS = AggValueSlot::forAddr(
2013 curAddr, type.getQualifiers(), AggValueSlot::IsDestructed,
2014 AggValueSlot::DoesNotNeedGCBarriers, AggValueSlot::IsNotAliased,
2015 AggValueSlot::DoesNotOverlap, AggValueSlot::IsNotZeroed,
2016 NewPointerIsChecked ? AggValueSlot::IsSanitizerChecked
2017 : AggValueSlot::IsNotSanitizerChecked);
2018 EmitCXXConstructorCall(ctor, Ctor_Complete, /*ForVirtualBase=*/false,
2019 /*Delegating=*/false, currAVS, E);
2020 }
2021
2022 // Go to the next element.
2023 llvm::Value *next =
2024 Builder.CreateInBoundsGEP(cur, llvm::ConstantInt::get(SizeTy, 1),
2025 "arrayctor.next");
2026 cur->addIncoming(next, Builder.GetInsertBlock());
2027
2028 // Check whether that's the end of the loop.
2029 llvm::Value *done = Builder.CreateICmpEQ(next, arrayEnd, "arrayctor.done");
2030 llvm::BasicBlock *contBB = createBasicBlock("arrayctor.cont");
2031 Builder.CreateCondBr(done, contBB, loopBB);
2032
2033 // Patch the earlier check to skip over the loop.
2034 if (zeroCheckBranch) zeroCheckBranch->setSuccessor(0, contBB);
2035
2036 EmitBlock(contBB);
2037 }
2038
destroyCXXObject(CodeGenFunction & CGF,Address addr,QualType type)2039 void CodeGenFunction::destroyCXXObject(CodeGenFunction &CGF,
2040 Address addr,
2041 QualType type) {
2042 const RecordType *rtype = type->castAs<RecordType>();
2043 const CXXRecordDecl *record = cast<CXXRecordDecl>(rtype->getDecl());
2044 const CXXDestructorDecl *dtor = record->getDestructor();
2045 assert(!dtor->isTrivial());
2046 CGF.EmitCXXDestructorCall(dtor, Dtor_Complete, /*for vbase*/ false,
2047 /*Delegating=*/false, addr, type);
2048 }
2049
EmitCXXConstructorCall(const CXXConstructorDecl * D,CXXCtorType Type,bool ForVirtualBase,bool Delegating,AggValueSlot ThisAVS,const CXXConstructExpr * E)2050 void CodeGenFunction::EmitCXXConstructorCall(const CXXConstructorDecl *D,
2051 CXXCtorType Type,
2052 bool ForVirtualBase,
2053 bool Delegating,
2054 AggValueSlot ThisAVS,
2055 const CXXConstructExpr *E) {
2056 CallArgList Args;
2057 Address This = ThisAVS.getAddress();
2058 LangAS SlotAS = ThisAVS.getQualifiers().getAddressSpace();
2059 QualType ThisType = D->getThisType();
2060 LangAS ThisAS = ThisType.getTypePtr()->getPointeeType().getAddressSpace();
2061 llvm::Value *ThisPtr = This.getPointer();
2062
2063 if (SlotAS != ThisAS) {
2064 unsigned TargetThisAS = getContext().getTargetAddressSpace(ThisAS);
2065 llvm::Type *NewType =
2066 ThisPtr->getType()->getPointerElementType()->getPointerTo(TargetThisAS);
2067 ThisPtr = getTargetHooks().performAddrSpaceCast(*this, This.getPointer(),
2068 ThisAS, SlotAS, NewType);
2069 }
2070
2071 // Push the this ptr.
2072 Args.add(RValue::get(ThisPtr), D->getThisType());
2073
2074 // If this is a trivial constructor, emit a memcpy now before we lose
2075 // the alignment information on the argument.
2076 // FIXME: It would be better to preserve alignment information into CallArg.
2077 if (isMemcpyEquivalentSpecialMember(D)) {
2078 assert(E->getNumArgs() == 1 && "unexpected argcount for trivial ctor");
2079
2080 const Expr *Arg = E->getArg(0);
2081 LValue Src = EmitLValue(Arg);
2082 QualType DestTy = getContext().getTypeDeclType(D->getParent());
2083 LValue Dest = MakeAddrLValue(This, DestTy);
2084 EmitAggregateCopyCtor(Dest, Src, ThisAVS.mayOverlap());
2085 return;
2086 }
2087
2088 // Add the rest of the user-supplied arguments.
2089 const FunctionProtoType *FPT = D->getType()->castAs<FunctionProtoType>();
2090 EvaluationOrder Order = E->isListInitialization()
2091 ? EvaluationOrder::ForceLeftToRight
2092 : EvaluationOrder::Default;
2093 EmitCallArgs(Args, FPT, E->arguments(), E->getConstructor(),
2094 /*ParamsToSkip*/ 0, Order);
2095
2096 EmitCXXConstructorCall(D, Type, ForVirtualBase, Delegating, This, Args,
2097 ThisAVS.mayOverlap(), E->getExprLoc(),
2098 ThisAVS.isSanitizerChecked());
2099 }
2100
canEmitDelegateCallArgs(CodeGenFunction & CGF,const CXXConstructorDecl * Ctor,CXXCtorType Type,CallArgList & Args)2101 static bool canEmitDelegateCallArgs(CodeGenFunction &CGF,
2102 const CXXConstructorDecl *Ctor,
2103 CXXCtorType Type, CallArgList &Args) {
2104 // We can't forward a variadic call.
2105 if (Ctor->isVariadic())
2106 return false;
2107
2108 if (CGF.getTarget().getCXXABI().areArgsDestroyedLeftToRightInCallee()) {
2109 // If the parameters are callee-cleanup, it's not safe to forward.
2110 for (auto *P : Ctor->parameters())
2111 if (P->needsDestruction(CGF.getContext()))
2112 return false;
2113
2114 // Likewise if they're inalloca.
2115 const CGFunctionInfo &Info =
2116 CGF.CGM.getTypes().arrangeCXXConstructorCall(Args, Ctor, Type, 0, 0);
2117 if (Info.usesInAlloca())
2118 return false;
2119 }
2120
2121 // Anything else should be OK.
2122 return true;
2123 }
2124
EmitCXXConstructorCall(const CXXConstructorDecl * D,CXXCtorType Type,bool ForVirtualBase,bool Delegating,Address This,CallArgList & Args,AggValueSlot::Overlap_t Overlap,SourceLocation Loc,bool NewPointerIsChecked)2125 void CodeGenFunction::EmitCXXConstructorCall(const CXXConstructorDecl *D,
2126 CXXCtorType Type,
2127 bool ForVirtualBase,
2128 bool Delegating,
2129 Address This,
2130 CallArgList &Args,
2131 AggValueSlot::Overlap_t Overlap,
2132 SourceLocation Loc,
2133 bool NewPointerIsChecked) {
2134 const CXXRecordDecl *ClassDecl = D->getParent();
2135
2136 if (!NewPointerIsChecked)
2137 EmitTypeCheck(CodeGenFunction::TCK_ConstructorCall, Loc, This.getPointer(),
2138 getContext().getRecordType(ClassDecl), CharUnits::Zero());
2139
2140 if (D->isTrivial() && D->isDefaultConstructor()) {
2141 assert(Args.size() == 1 && "trivial default ctor with args");
2142 return;
2143 }
2144
2145 // If this is a trivial constructor, just emit what's needed. If this is a
2146 // union copy constructor, we must emit a memcpy, because the AST does not
2147 // model that copy.
2148 if (isMemcpyEquivalentSpecialMember(D)) {
2149 assert(Args.size() == 2 && "unexpected argcount for trivial ctor");
2150
2151 QualType SrcTy = D->getParamDecl(0)->getType().getNonReferenceType();
2152 Address Src(Args[1].getRValue(*this).getScalarVal(),
2153 CGM.getNaturalTypeAlignment(SrcTy));
2154 LValue SrcLVal = MakeAddrLValue(Src, SrcTy);
2155 QualType DestTy = getContext().getTypeDeclType(ClassDecl);
2156 LValue DestLVal = MakeAddrLValue(This, DestTy);
2157 EmitAggregateCopyCtor(DestLVal, SrcLVal, Overlap);
2158 return;
2159 }
2160
2161 bool PassPrototypeArgs = true;
2162 // Check whether we can actually emit the constructor before trying to do so.
2163 if (auto Inherited = D->getInheritedConstructor()) {
2164 PassPrototypeArgs = getTypes().inheritingCtorHasParams(Inherited, Type);
2165 if (PassPrototypeArgs && !canEmitDelegateCallArgs(*this, D, Type, Args)) {
2166 EmitInlinedInheritingCXXConstructorCall(D, Type, ForVirtualBase,
2167 Delegating, Args);
2168 return;
2169 }
2170 }
2171
2172 // Insert any ABI-specific implicit constructor arguments.
2173 CGCXXABI::AddedStructorArgCounts ExtraArgs =
2174 CGM.getCXXABI().addImplicitConstructorArgs(*this, D, Type, ForVirtualBase,
2175 Delegating, Args);
2176
2177 // Emit the call.
2178 llvm::Constant *CalleePtr = CGM.getAddrOfCXXStructor(GlobalDecl(D, Type));
2179 const CGFunctionInfo &Info = CGM.getTypes().arrangeCXXConstructorCall(
2180 Args, D, Type, ExtraArgs.Prefix, ExtraArgs.Suffix, PassPrototypeArgs);
2181 CGCallee Callee = CGCallee::forDirect(CalleePtr, GlobalDecl(D, Type));
2182 EmitCall(Info, Callee, ReturnValueSlot(), Args, nullptr, Loc);
2183
2184 // Generate vtable assumptions if we're constructing a complete object
2185 // with a vtable. We don't do this for base subobjects for two reasons:
2186 // first, it's incorrect for classes with virtual bases, and second, we're
2187 // about to overwrite the vptrs anyway.
2188 // We also have to make sure if we can refer to vtable:
2189 // - Otherwise we can refer to vtable if it's safe to speculatively emit.
2190 // FIXME: If vtable is used by ctor/dtor, or if vtable is external and we are
2191 // sure that definition of vtable is not hidden,
2192 // then we are always safe to refer to it.
2193 // FIXME: It looks like InstCombine is very inefficient on dealing with
2194 // assumes. Make assumption loads require -fstrict-vtable-pointers temporarily.
2195 if (CGM.getCodeGenOpts().OptimizationLevel > 0 &&
2196 ClassDecl->isDynamicClass() && Type != Ctor_Base &&
2197 CGM.getCXXABI().canSpeculativelyEmitVTable(ClassDecl) &&
2198 CGM.getCodeGenOpts().StrictVTablePointers)
2199 EmitVTableAssumptionLoads(ClassDecl, This);
2200 }
2201
EmitInheritedCXXConstructorCall(const CXXConstructorDecl * D,bool ForVirtualBase,Address This,bool InheritedFromVBase,const CXXInheritedCtorInitExpr * E)2202 void CodeGenFunction::EmitInheritedCXXConstructorCall(
2203 const CXXConstructorDecl *D, bool ForVirtualBase, Address This,
2204 bool InheritedFromVBase, const CXXInheritedCtorInitExpr *E) {
2205 CallArgList Args;
2206 CallArg ThisArg(RValue::get(This.getPointer()), D->getThisType());
2207
2208 // Forward the parameters.
2209 if (InheritedFromVBase &&
2210 CGM.getTarget().getCXXABI().hasConstructorVariants()) {
2211 // Nothing to do; this construction is not responsible for constructing
2212 // the base class containing the inherited constructor.
2213 // FIXME: Can we just pass undef's for the remaining arguments if we don't
2214 // have constructor variants?
2215 Args.push_back(ThisArg);
2216 } else if (!CXXInheritedCtorInitExprArgs.empty()) {
2217 // The inheriting constructor was inlined; just inject its arguments.
2218 assert(CXXInheritedCtorInitExprArgs.size() >= D->getNumParams() &&
2219 "wrong number of parameters for inherited constructor call");
2220 Args = CXXInheritedCtorInitExprArgs;
2221 Args[0] = ThisArg;
2222 } else {
2223 // The inheriting constructor was not inlined. Emit delegating arguments.
2224 Args.push_back(ThisArg);
2225 const auto *OuterCtor = cast<CXXConstructorDecl>(CurCodeDecl);
2226 assert(OuterCtor->getNumParams() == D->getNumParams());
2227 assert(!OuterCtor->isVariadic() && "should have been inlined");
2228
2229 for (const auto *Param : OuterCtor->parameters()) {
2230 assert(getContext().hasSameUnqualifiedType(
2231 OuterCtor->getParamDecl(Param->getFunctionScopeIndex())->getType(),
2232 Param->getType()));
2233 EmitDelegateCallArg(Args, Param, E->getLocation());
2234
2235 // Forward __attribute__(pass_object_size).
2236 if (Param->hasAttr<PassObjectSizeAttr>()) {
2237 auto *POSParam = SizeArguments[Param];
2238 assert(POSParam && "missing pass_object_size value for forwarding");
2239 EmitDelegateCallArg(Args, POSParam, E->getLocation());
2240 }
2241 }
2242 }
2243
2244 EmitCXXConstructorCall(D, Ctor_Base, ForVirtualBase, /*Delegating*/false,
2245 This, Args, AggValueSlot::MayOverlap,
2246 E->getLocation(), /*NewPointerIsChecked*/true);
2247 }
2248
EmitInlinedInheritingCXXConstructorCall(const CXXConstructorDecl * Ctor,CXXCtorType CtorType,bool ForVirtualBase,bool Delegating,CallArgList & Args)2249 void CodeGenFunction::EmitInlinedInheritingCXXConstructorCall(
2250 const CXXConstructorDecl *Ctor, CXXCtorType CtorType, bool ForVirtualBase,
2251 bool Delegating, CallArgList &Args) {
2252 GlobalDecl GD(Ctor, CtorType);
2253 InlinedInheritingConstructorScope Scope(*this, GD);
2254 ApplyInlineDebugLocation DebugScope(*this, GD);
2255 RunCleanupsScope RunCleanups(*this);
2256
2257 // Save the arguments to be passed to the inherited constructor.
2258 CXXInheritedCtorInitExprArgs = Args;
2259
2260 FunctionArgList Params;
2261 QualType RetType = BuildFunctionArgList(CurGD, Params);
2262 FnRetTy = RetType;
2263
2264 // Insert any ABI-specific implicit constructor arguments.
2265 CGM.getCXXABI().addImplicitConstructorArgs(*this, Ctor, CtorType,
2266 ForVirtualBase, Delegating, Args);
2267
2268 // Emit a simplified prolog. We only need to emit the implicit params.
2269 assert(Args.size() >= Params.size() && "too few arguments for call");
2270 for (unsigned I = 0, N = Args.size(); I != N; ++I) {
2271 if (I < Params.size() && isa<ImplicitParamDecl>(Params[I])) {
2272 const RValue &RV = Args[I].getRValue(*this);
2273 assert(!RV.isComplex() && "complex indirect params not supported");
2274 ParamValue Val = RV.isScalar()
2275 ? ParamValue::forDirect(RV.getScalarVal())
2276 : ParamValue::forIndirect(RV.getAggregateAddress());
2277 EmitParmDecl(*Params[I], Val, I + 1);
2278 }
2279 }
2280
2281 // Create a return value slot if the ABI implementation wants one.
2282 // FIXME: This is dumb, we should ask the ABI not to try to set the return
2283 // value instead.
2284 if (!RetType->isVoidType())
2285 ReturnValue = CreateIRTemp(RetType, "retval.inhctor");
2286
2287 CGM.getCXXABI().EmitInstanceFunctionProlog(*this);
2288 CXXThisValue = CXXABIThisValue;
2289
2290 // Directly emit the constructor initializers.
2291 EmitCtorPrologue(Ctor, CtorType, Params);
2292 }
2293
EmitVTableAssumptionLoad(const VPtr & Vptr,Address This)2294 void CodeGenFunction::EmitVTableAssumptionLoad(const VPtr &Vptr, Address This) {
2295 llvm::Value *VTableGlobal =
2296 CGM.getCXXABI().getVTableAddressPoint(Vptr.Base, Vptr.VTableClass);
2297 if (!VTableGlobal)
2298 return;
2299
2300 // We can just use the base offset in the complete class.
2301 CharUnits NonVirtualOffset = Vptr.Base.getBaseOffset();
2302
2303 if (!NonVirtualOffset.isZero())
2304 This =
2305 ApplyNonVirtualAndVirtualOffset(*this, This, NonVirtualOffset, nullptr,
2306 Vptr.VTableClass, Vptr.NearestVBase);
2307
2308 llvm::Value *VPtrValue =
2309 GetVTablePtr(This, VTableGlobal->getType(), Vptr.VTableClass);
2310 llvm::Value *Cmp =
2311 Builder.CreateICmpEQ(VPtrValue, VTableGlobal, "cmp.vtables");
2312 Builder.CreateAssumption(Cmp);
2313 }
2314
EmitVTableAssumptionLoads(const CXXRecordDecl * ClassDecl,Address This)2315 void CodeGenFunction::EmitVTableAssumptionLoads(const CXXRecordDecl *ClassDecl,
2316 Address This) {
2317 if (CGM.getCXXABI().doStructorsInitializeVPtrs(ClassDecl))
2318 for (const VPtr &Vptr : getVTablePointers(ClassDecl))
2319 EmitVTableAssumptionLoad(Vptr, This);
2320 }
2321
2322 void
EmitSynthesizedCXXCopyCtorCall(const CXXConstructorDecl * D,Address This,Address Src,const CXXConstructExpr * E)2323 CodeGenFunction::EmitSynthesizedCXXCopyCtorCall(const CXXConstructorDecl *D,
2324 Address This, Address Src,
2325 const CXXConstructExpr *E) {
2326 const FunctionProtoType *FPT = D->getType()->castAs<FunctionProtoType>();
2327
2328 CallArgList Args;
2329
2330 // Push the this ptr.
2331 Args.add(RValue::get(This.getPointer()), D->getThisType());
2332
2333 // Push the src ptr.
2334 QualType QT = *(FPT->param_type_begin());
2335 llvm::Type *t = CGM.getTypes().ConvertType(QT);
2336 Src = Builder.CreateBitCast(Src, t);
2337 Args.add(RValue::get(Src.getPointer()), QT);
2338
2339 // Skip over first argument (Src).
2340 EmitCallArgs(Args, FPT, drop_begin(E->arguments(), 1), E->getConstructor(),
2341 /*ParamsToSkip*/ 1);
2342
2343 EmitCXXConstructorCall(D, Ctor_Complete, /*ForVirtualBase*/false,
2344 /*Delegating*/false, This, Args,
2345 AggValueSlot::MayOverlap, E->getExprLoc(),
2346 /*NewPointerIsChecked*/false);
2347 }
2348
2349 void
EmitDelegateCXXConstructorCall(const CXXConstructorDecl * Ctor,CXXCtorType CtorType,const FunctionArgList & Args,SourceLocation Loc)2350 CodeGenFunction::EmitDelegateCXXConstructorCall(const CXXConstructorDecl *Ctor,
2351 CXXCtorType CtorType,
2352 const FunctionArgList &Args,
2353 SourceLocation Loc) {
2354 CallArgList DelegateArgs;
2355
2356 FunctionArgList::const_iterator I = Args.begin(), E = Args.end();
2357 assert(I != E && "no parameters to constructor");
2358
2359 // this
2360 Address This = LoadCXXThisAddress();
2361 DelegateArgs.add(RValue::get(This.getPointer()), (*I)->getType());
2362 ++I;
2363
2364 // FIXME: The location of the VTT parameter in the parameter list is
2365 // specific to the Itanium ABI and shouldn't be hardcoded here.
2366 if (CGM.getCXXABI().NeedsVTTParameter(CurGD)) {
2367 assert(I != E && "cannot skip vtt parameter, already done with args");
2368 assert((*I)->getType()->isPointerType() &&
2369 "skipping parameter not of vtt type");
2370 ++I;
2371 }
2372
2373 // Explicit arguments.
2374 for (; I != E; ++I) {
2375 const VarDecl *param = *I;
2376 // FIXME: per-argument source location
2377 EmitDelegateCallArg(DelegateArgs, param, Loc);
2378 }
2379
2380 EmitCXXConstructorCall(Ctor, CtorType, /*ForVirtualBase=*/false,
2381 /*Delegating=*/true, This, DelegateArgs,
2382 AggValueSlot::MayOverlap, Loc,
2383 /*NewPointerIsChecked=*/true);
2384 }
2385
2386 namespace {
2387 struct CallDelegatingCtorDtor final : EHScopeStack::Cleanup {
2388 const CXXDestructorDecl *Dtor;
2389 Address Addr;
2390 CXXDtorType Type;
2391
CallDelegatingCtorDtor__anon463df5f00511::CallDelegatingCtorDtor2392 CallDelegatingCtorDtor(const CXXDestructorDecl *D, Address Addr,
2393 CXXDtorType Type)
2394 : Dtor(D), Addr(Addr), Type(Type) {}
2395
Emit__anon463df5f00511::CallDelegatingCtorDtor2396 void Emit(CodeGenFunction &CGF, Flags flags) override {
2397 // We are calling the destructor from within the constructor.
2398 // Therefore, "this" should have the expected type.
2399 QualType ThisTy = Dtor->getThisObjectType();
2400 CGF.EmitCXXDestructorCall(Dtor, Type, /*ForVirtualBase=*/false,
2401 /*Delegating=*/true, Addr, ThisTy);
2402 }
2403 };
2404 } // end anonymous namespace
2405
2406 void
EmitDelegatingCXXConstructorCall(const CXXConstructorDecl * Ctor,const FunctionArgList & Args)2407 CodeGenFunction::EmitDelegatingCXXConstructorCall(const CXXConstructorDecl *Ctor,
2408 const FunctionArgList &Args) {
2409 assert(Ctor->isDelegatingConstructor());
2410
2411 Address ThisPtr = LoadCXXThisAddress();
2412
2413 AggValueSlot AggSlot =
2414 AggValueSlot::forAddr(ThisPtr, Qualifiers(),
2415 AggValueSlot::IsDestructed,
2416 AggValueSlot::DoesNotNeedGCBarriers,
2417 AggValueSlot::IsNotAliased,
2418 AggValueSlot::MayOverlap,
2419 AggValueSlot::IsNotZeroed,
2420 // Checks are made by the code that calls constructor.
2421 AggValueSlot::IsSanitizerChecked);
2422
2423 EmitAggExpr(Ctor->init_begin()[0]->getInit(), AggSlot);
2424
2425 const CXXRecordDecl *ClassDecl = Ctor->getParent();
2426 if (CGM.getLangOpts().Exceptions && !ClassDecl->hasTrivialDestructor()) {
2427 CXXDtorType Type =
2428 CurGD.getCtorType() == Ctor_Complete ? Dtor_Complete : Dtor_Base;
2429
2430 EHStack.pushCleanup<CallDelegatingCtorDtor>(EHCleanup,
2431 ClassDecl->getDestructor(),
2432 ThisPtr, Type);
2433 }
2434 }
2435
EmitCXXDestructorCall(const CXXDestructorDecl * DD,CXXDtorType Type,bool ForVirtualBase,bool Delegating,Address This,QualType ThisTy)2436 void CodeGenFunction::EmitCXXDestructorCall(const CXXDestructorDecl *DD,
2437 CXXDtorType Type,
2438 bool ForVirtualBase,
2439 bool Delegating, Address This,
2440 QualType ThisTy) {
2441 CGM.getCXXABI().EmitDestructorCall(*this, DD, Type, ForVirtualBase,
2442 Delegating, This, ThisTy);
2443 }
2444
2445 namespace {
2446 struct CallLocalDtor final : EHScopeStack::Cleanup {
2447 const CXXDestructorDecl *Dtor;
2448 Address Addr;
2449 QualType Ty;
2450
CallLocalDtor__anon463df5f00611::CallLocalDtor2451 CallLocalDtor(const CXXDestructorDecl *D, Address Addr, QualType Ty)
2452 : Dtor(D), Addr(Addr), Ty(Ty) {}
2453
Emit__anon463df5f00611::CallLocalDtor2454 void Emit(CodeGenFunction &CGF, Flags flags) override {
2455 CGF.EmitCXXDestructorCall(Dtor, Dtor_Complete,
2456 /*ForVirtualBase=*/false,
2457 /*Delegating=*/false, Addr, Ty);
2458 }
2459 };
2460 } // end anonymous namespace
2461
PushDestructorCleanup(const CXXDestructorDecl * D,QualType T,Address Addr)2462 void CodeGenFunction::PushDestructorCleanup(const CXXDestructorDecl *D,
2463 QualType T, Address Addr) {
2464 EHStack.pushCleanup<CallLocalDtor>(NormalAndEHCleanup, D, Addr, T);
2465 }
2466
PushDestructorCleanup(QualType T,Address Addr)2467 void CodeGenFunction::PushDestructorCleanup(QualType T, Address Addr) {
2468 CXXRecordDecl *ClassDecl = T->getAsCXXRecordDecl();
2469 if (!ClassDecl) return;
2470 if (ClassDecl->hasTrivialDestructor()) return;
2471
2472 const CXXDestructorDecl *D = ClassDecl->getDestructor();
2473 assert(D && D->isUsed() && "destructor not marked as used!");
2474 PushDestructorCleanup(D, T, Addr);
2475 }
2476
InitializeVTablePointer(const VPtr & Vptr)2477 void CodeGenFunction::InitializeVTablePointer(const VPtr &Vptr) {
2478 // Compute the address point.
2479 llvm::Value *VTableAddressPoint =
2480 CGM.getCXXABI().getVTableAddressPointInStructor(
2481 *this, Vptr.VTableClass, Vptr.Base, Vptr.NearestVBase);
2482
2483 if (!VTableAddressPoint)
2484 return;
2485
2486 // Compute where to store the address point.
2487 llvm::Value *VirtualOffset = nullptr;
2488 CharUnits NonVirtualOffset = CharUnits::Zero();
2489
2490 if (CGM.getCXXABI().isVirtualOffsetNeededForVTableField(*this, Vptr)) {
2491 // We need to use the virtual base offset offset because the virtual base
2492 // might have a different offset in the most derived class.
2493
2494 VirtualOffset = CGM.getCXXABI().GetVirtualBaseClassOffset(
2495 *this, LoadCXXThisAddress(), Vptr.VTableClass, Vptr.NearestVBase);
2496 NonVirtualOffset = Vptr.OffsetFromNearestVBase;
2497 } else {
2498 // We can just use the base offset in the complete class.
2499 NonVirtualOffset = Vptr.Base.getBaseOffset();
2500 }
2501
2502 // Apply the offsets.
2503 Address VTableField = LoadCXXThisAddress();
2504
2505 if (!NonVirtualOffset.isZero() || VirtualOffset)
2506 VTableField = ApplyNonVirtualAndVirtualOffset(
2507 *this, VTableField, NonVirtualOffset, VirtualOffset, Vptr.VTableClass,
2508 Vptr.NearestVBase);
2509
2510 // Finally, store the address point. Use the same LLVM types as the field to
2511 // support optimization.
2512 llvm::Type *VTablePtrTy =
2513 llvm::FunctionType::get(CGM.Int32Ty, /*isVarArg=*/true)
2514 ->getPointerTo()
2515 ->getPointerTo();
2516 VTableField = Builder.CreateBitCast(VTableField, VTablePtrTy->getPointerTo());
2517 VTableAddressPoint = Builder.CreateBitCast(VTableAddressPoint, VTablePtrTy);
2518
2519 llvm::StoreInst *Store = Builder.CreateStore(VTableAddressPoint, VTableField);
2520 TBAAAccessInfo TBAAInfo = CGM.getTBAAVTablePtrAccessInfo(VTablePtrTy);
2521 CGM.DecorateInstructionWithTBAA(Store, TBAAInfo);
2522 if (CGM.getCodeGenOpts().OptimizationLevel > 0 &&
2523 CGM.getCodeGenOpts().StrictVTablePointers)
2524 CGM.DecorateInstructionWithInvariantGroup(Store, Vptr.VTableClass);
2525 }
2526
2527 CodeGenFunction::VPtrsVector
getVTablePointers(const CXXRecordDecl * VTableClass)2528 CodeGenFunction::getVTablePointers(const CXXRecordDecl *VTableClass) {
2529 CodeGenFunction::VPtrsVector VPtrsResult;
2530 VisitedVirtualBasesSetTy VBases;
2531 getVTablePointers(BaseSubobject(VTableClass, CharUnits::Zero()),
2532 /*NearestVBase=*/nullptr,
2533 /*OffsetFromNearestVBase=*/CharUnits::Zero(),
2534 /*BaseIsNonVirtualPrimaryBase=*/false, VTableClass, VBases,
2535 VPtrsResult);
2536 return VPtrsResult;
2537 }
2538
getVTablePointers(BaseSubobject Base,const CXXRecordDecl * NearestVBase,CharUnits OffsetFromNearestVBase,bool BaseIsNonVirtualPrimaryBase,const CXXRecordDecl * VTableClass,VisitedVirtualBasesSetTy & VBases,VPtrsVector & Vptrs)2539 void CodeGenFunction::getVTablePointers(BaseSubobject Base,
2540 const CXXRecordDecl *NearestVBase,
2541 CharUnits OffsetFromNearestVBase,
2542 bool BaseIsNonVirtualPrimaryBase,
2543 const CXXRecordDecl *VTableClass,
2544 VisitedVirtualBasesSetTy &VBases,
2545 VPtrsVector &Vptrs) {
2546 // If this base is a non-virtual primary base the address point has already
2547 // been set.
2548 if (!BaseIsNonVirtualPrimaryBase) {
2549 // Initialize the vtable pointer for this base.
2550 VPtr Vptr = {Base, NearestVBase, OffsetFromNearestVBase, VTableClass};
2551 Vptrs.push_back(Vptr);
2552 }
2553
2554 const CXXRecordDecl *RD = Base.getBase();
2555
2556 // Traverse bases.
2557 for (const auto &I : RD->bases()) {
2558 auto *BaseDecl =
2559 cast<CXXRecordDecl>(I.getType()->castAs<RecordType>()->getDecl());
2560
2561 // Ignore classes without a vtable.
2562 if (!BaseDecl->isDynamicClass())
2563 continue;
2564
2565 CharUnits BaseOffset;
2566 CharUnits BaseOffsetFromNearestVBase;
2567 bool BaseDeclIsNonVirtualPrimaryBase;
2568
2569 if (I.isVirtual()) {
2570 // Check if we've visited this virtual base before.
2571 if (!VBases.insert(BaseDecl).second)
2572 continue;
2573
2574 const ASTRecordLayout &Layout =
2575 getContext().getASTRecordLayout(VTableClass);
2576
2577 BaseOffset = Layout.getVBaseClassOffset(BaseDecl);
2578 BaseOffsetFromNearestVBase = CharUnits::Zero();
2579 BaseDeclIsNonVirtualPrimaryBase = false;
2580 } else {
2581 const ASTRecordLayout &Layout = getContext().getASTRecordLayout(RD);
2582
2583 BaseOffset = Base.getBaseOffset() + Layout.getBaseClassOffset(BaseDecl);
2584 BaseOffsetFromNearestVBase =
2585 OffsetFromNearestVBase + Layout.getBaseClassOffset(BaseDecl);
2586 BaseDeclIsNonVirtualPrimaryBase = Layout.getPrimaryBase() == BaseDecl;
2587 }
2588
2589 getVTablePointers(
2590 BaseSubobject(BaseDecl, BaseOffset),
2591 I.isVirtual() ? BaseDecl : NearestVBase, BaseOffsetFromNearestVBase,
2592 BaseDeclIsNonVirtualPrimaryBase, VTableClass, VBases, Vptrs);
2593 }
2594 }
2595
InitializeVTablePointers(const CXXRecordDecl * RD)2596 void CodeGenFunction::InitializeVTablePointers(const CXXRecordDecl *RD) {
2597 // Ignore classes without a vtable.
2598 if (!RD->isDynamicClass())
2599 return;
2600
2601 // Initialize the vtable pointers for this class and all of its bases.
2602 if (CGM.getCXXABI().doStructorsInitializeVPtrs(RD))
2603 for (const VPtr &Vptr : getVTablePointers(RD))
2604 InitializeVTablePointer(Vptr);
2605
2606 if (RD->getNumVBases())
2607 CGM.getCXXABI().initializeHiddenVirtualInheritanceMembers(*this, RD);
2608 }
2609
GetVTablePtr(Address This,llvm::Type * VTableTy,const CXXRecordDecl * RD)2610 llvm::Value *CodeGenFunction::GetVTablePtr(Address This,
2611 llvm::Type *VTableTy,
2612 const CXXRecordDecl *RD) {
2613 Address VTablePtrSrc = Builder.CreateElementBitCast(This, VTableTy);
2614 llvm::Instruction *VTable = Builder.CreateLoad(VTablePtrSrc, "vtable");
2615 TBAAAccessInfo TBAAInfo = CGM.getTBAAVTablePtrAccessInfo(VTableTy);
2616 CGM.DecorateInstructionWithTBAA(VTable, TBAAInfo);
2617
2618 if (CGM.getCodeGenOpts().OptimizationLevel > 0 &&
2619 CGM.getCodeGenOpts().StrictVTablePointers)
2620 CGM.DecorateInstructionWithInvariantGroup(VTable, RD);
2621
2622 return VTable;
2623 }
2624
2625 // If a class has a single non-virtual base and does not introduce or override
2626 // virtual member functions or fields, it will have the same layout as its base.
2627 // This function returns the least derived such class.
2628 //
2629 // Casting an instance of a base class to such a derived class is technically
2630 // undefined behavior, but it is a relatively common hack for introducing member
2631 // functions on class instances with specific properties (e.g. llvm::Operator)
2632 // that works under most compilers and should not have security implications, so
2633 // we allow it by default. It can be disabled with -fsanitize=cfi-cast-strict.
2634 static const CXXRecordDecl *
LeastDerivedClassWithSameLayout(const CXXRecordDecl * RD)2635 LeastDerivedClassWithSameLayout(const CXXRecordDecl *RD) {
2636 if (!RD->field_empty())
2637 return RD;
2638
2639 if (RD->getNumVBases() != 0)
2640 return RD;
2641
2642 if (RD->getNumBases() != 1)
2643 return RD;
2644
2645 for (const CXXMethodDecl *MD : RD->methods()) {
2646 if (MD->isVirtual()) {
2647 // Virtual member functions are only ok if they are implicit destructors
2648 // because the implicit destructor will have the same semantics as the
2649 // base class's destructor if no fields are added.
2650 if (isa<CXXDestructorDecl>(MD) && MD->isImplicit())
2651 continue;
2652 return RD;
2653 }
2654 }
2655
2656 return LeastDerivedClassWithSameLayout(
2657 RD->bases_begin()->getType()->getAsCXXRecordDecl());
2658 }
2659
EmitTypeMetadataCodeForVCall(const CXXRecordDecl * RD,llvm::Value * VTable,SourceLocation Loc)2660 void CodeGenFunction::EmitTypeMetadataCodeForVCall(const CXXRecordDecl *RD,
2661 llvm::Value *VTable,
2662 SourceLocation Loc) {
2663 if (SanOpts.has(SanitizerKind::CFIVCall))
2664 EmitVTablePtrCheckForCall(RD, VTable, CodeGenFunction::CFITCK_VCall, Loc);
2665 else if (CGM.getCodeGenOpts().WholeProgramVTables &&
2666 // Don't insert type test assumes if we are forcing public std
2667 // visibility.
2668 !CGM.HasLTOVisibilityPublicStd(RD)) {
2669 llvm::Metadata *MD =
2670 CGM.CreateMetadataIdentifierForType(QualType(RD->getTypeForDecl(), 0));
2671 llvm::Value *TypeId =
2672 llvm::MetadataAsValue::get(CGM.getLLVMContext(), MD);
2673
2674 llvm::Value *CastedVTable = Builder.CreateBitCast(VTable, Int8PtrTy);
2675 llvm::Value *TypeTest =
2676 Builder.CreateCall(CGM.getIntrinsic(llvm::Intrinsic::type_test),
2677 {CastedVTable, TypeId});
2678 Builder.CreateCall(CGM.getIntrinsic(llvm::Intrinsic::assume), TypeTest);
2679 }
2680 }
2681
EmitVTablePtrCheckForCall(const CXXRecordDecl * RD,llvm::Value * VTable,CFITypeCheckKind TCK,SourceLocation Loc)2682 void CodeGenFunction::EmitVTablePtrCheckForCall(const CXXRecordDecl *RD,
2683 llvm::Value *VTable,
2684 CFITypeCheckKind TCK,
2685 SourceLocation Loc) {
2686 if (!SanOpts.has(SanitizerKind::CFICastStrict))
2687 RD = LeastDerivedClassWithSameLayout(RD);
2688
2689 EmitVTablePtrCheck(RD, VTable, TCK, Loc);
2690 }
2691
EmitVTablePtrCheckForCast(QualType T,llvm::Value * Derived,bool MayBeNull,CFITypeCheckKind TCK,SourceLocation Loc)2692 void CodeGenFunction::EmitVTablePtrCheckForCast(QualType T,
2693 llvm::Value *Derived,
2694 bool MayBeNull,
2695 CFITypeCheckKind TCK,
2696 SourceLocation Loc) {
2697 if (!getLangOpts().CPlusPlus)
2698 return;
2699
2700 auto *ClassTy = T->getAs<RecordType>();
2701 if (!ClassTy)
2702 return;
2703
2704 const CXXRecordDecl *ClassDecl = cast<CXXRecordDecl>(ClassTy->getDecl());
2705
2706 if (!ClassDecl->isCompleteDefinition() || !ClassDecl->isDynamicClass())
2707 return;
2708
2709 if (!SanOpts.has(SanitizerKind::CFICastStrict))
2710 ClassDecl = LeastDerivedClassWithSameLayout(ClassDecl);
2711
2712 llvm::BasicBlock *ContBlock = nullptr;
2713
2714 if (MayBeNull) {
2715 llvm::Value *DerivedNotNull =
2716 Builder.CreateIsNotNull(Derived, "cast.nonnull");
2717
2718 llvm::BasicBlock *CheckBlock = createBasicBlock("cast.check");
2719 ContBlock = createBasicBlock("cast.cont");
2720
2721 Builder.CreateCondBr(DerivedNotNull, CheckBlock, ContBlock);
2722
2723 EmitBlock(CheckBlock);
2724 }
2725
2726 llvm::Value *VTable;
2727 std::tie(VTable, ClassDecl) = CGM.getCXXABI().LoadVTablePtr(
2728 *this, Address(Derived, getPointerAlign()), ClassDecl);
2729
2730 EmitVTablePtrCheck(ClassDecl, VTable, TCK, Loc);
2731
2732 if (MayBeNull) {
2733 Builder.CreateBr(ContBlock);
2734 EmitBlock(ContBlock);
2735 }
2736 }
2737
EmitVTablePtrCheck(const CXXRecordDecl * RD,llvm::Value * VTable,CFITypeCheckKind TCK,SourceLocation Loc)2738 void CodeGenFunction::EmitVTablePtrCheck(const CXXRecordDecl *RD,
2739 llvm::Value *VTable,
2740 CFITypeCheckKind TCK,
2741 SourceLocation Loc) {
2742 if (!CGM.getCodeGenOpts().SanitizeCfiCrossDso &&
2743 !CGM.HasHiddenLTOVisibility(RD))
2744 return;
2745
2746 SanitizerMask M;
2747 llvm::SanitizerStatKind SSK;
2748 switch (TCK) {
2749 case CFITCK_VCall:
2750 M = SanitizerKind::CFIVCall;
2751 SSK = llvm::SanStat_CFI_VCall;
2752 break;
2753 case CFITCK_NVCall:
2754 M = SanitizerKind::CFINVCall;
2755 SSK = llvm::SanStat_CFI_NVCall;
2756 break;
2757 case CFITCK_DerivedCast:
2758 M = SanitizerKind::CFIDerivedCast;
2759 SSK = llvm::SanStat_CFI_DerivedCast;
2760 break;
2761 case CFITCK_UnrelatedCast:
2762 M = SanitizerKind::CFIUnrelatedCast;
2763 SSK = llvm::SanStat_CFI_UnrelatedCast;
2764 break;
2765 case CFITCK_ICall:
2766 case CFITCK_NVMFCall:
2767 case CFITCK_VMFCall:
2768 llvm_unreachable("unexpected sanitizer kind");
2769 }
2770
2771 std::string TypeName = RD->getQualifiedNameAsString();
2772 if (getContext().getSanitizerBlacklist().isBlacklistedType(M, TypeName))
2773 return;
2774
2775 SanitizerScope SanScope(this);
2776 EmitSanitizerStatReport(SSK);
2777
2778 llvm::Metadata *MD =
2779 CGM.CreateMetadataIdentifierForType(QualType(RD->getTypeForDecl(), 0));
2780 llvm::Value *TypeId = llvm::MetadataAsValue::get(getLLVMContext(), MD);
2781
2782 llvm::Value *CastedVTable = Builder.CreateBitCast(VTable, Int8PtrTy);
2783 llvm::Value *TypeTest = Builder.CreateCall(
2784 CGM.getIntrinsic(llvm::Intrinsic::type_test), {CastedVTable, TypeId});
2785
2786 llvm::Constant *StaticData[] = {
2787 llvm::ConstantInt::get(Int8Ty, TCK),
2788 EmitCheckSourceLocation(Loc),
2789 EmitCheckTypeDescriptor(QualType(RD->getTypeForDecl(), 0)),
2790 };
2791
2792 auto CrossDsoTypeId = CGM.CreateCrossDsoCfiTypeId(MD);
2793 if (CGM.getCodeGenOpts().SanitizeCfiCrossDso && CrossDsoTypeId) {
2794 EmitCfiSlowPathCheck(M, TypeTest, CrossDsoTypeId, CastedVTable, StaticData);
2795 return;
2796 }
2797
2798 if (CGM.getCodeGenOpts().SanitizeTrap.has(M)) {
2799 EmitTrapCheck(TypeTest);
2800 return;
2801 }
2802
2803 llvm::Value *AllVtables = llvm::MetadataAsValue::get(
2804 CGM.getLLVMContext(),
2805 llvm::MDString::get(CGM.getLLVMContext(), "all-vtables"));
2806 llvm::Value *ValidVtable = Builder.CreateCall(
2807 CGM.getIntrinsic(llvm::Intrinsic::type_test), {CastedVTable, AllVtables});
2808 EmitCheck(std::make_pair(TypeTest, M), SanitizerHandler::CFICheckFail,
2809 StaticData, {CastedVTable, ValidVtable});
2810 }
2811
ShouldEmitVTableTypeCheckedLoad(const CXXRecordDecl * RD)2812 bool CodeGenFunction::ShouldEmitVTableTypeCheckedLoad(const CXXRecordDecl *RD) {
2813 if (!CGM.getCodeGenOpts().WholeProgramVTables ||
2814 !CGM.HasHiddenLTOVisibility(RD))
2815 return false;
2816
2817 if (CGM.getCodeGenOpts().VirtualFunctionElimination)
2818 return true;
2819
2820 if (!SanOpts.has(SanitizerKind::CFIVCall) ||
2821 !CGM.getCodeGenOpts().SanitizeTrap.has(SanitizerKind::CFIVCall))
2822 return false;
2823
2824 std::string TypeName = RD->getQualifiedNameAsString();
2825 return !getContext().getSanitizerBlacklist().isBlacklistedType(
2826 SanitizerKind::CFIVCall, TypeName);
2827 }
2828
EmitVTableTypeCheckedLoad(const CXXRecordDecl * RD,llvm::Value * VTable,uint64_t VTableByteOffset)2829 llvm::Value *CodeGenFunction::EmitVTableTypeCheckedLoad(
2830 const CXXRecordDecl *RD, llvm::Value *VTable, uint64_t VTableByteOffset) {
2831 SanitizerScope SanScope(this);
2832
2833 EmitSanitizerStatReport(llvm::SanStat_CFI_VCall);
2834
2835 llvm::Metadata *MD =
2836 CGM.CreateMetadataIdentifierForType(QualType(RD->getTypeForDecl(), 0));
2837 llvm::Value *TypeId = llvm::MetadataAsValue::get(CGM.getLLVMContext(), MD);
2838
2839 llvm::Value *CastedVTable = Builder.CreateBitCast(VTable, Int8PtrTy);
2840 llvm::Value *CheckedLoad = Builder.CreateCall(
2841 CGM.getIntrinsic(llvm::Intrinsic::type_checked_load),
2842 {CastedVTable, llvm::ConstantInt::get(Int32Ty, VTableByteOffset),
2843 TypeId});
2844 llvm::Value *CheckResult = Builder.CreateExtractValue(CheckedLoad, 1);
2845
2846 std::string TypeName = RD->getQualifiedNameAsString();
2847 if (SanOpts.has(SanitizerKind::CFIVCall) &&
2848 !getContext().getSanitizerBlacklist().isBlacklistedType(
2849 SanitizerKind::CFIVCall, TypeName)) {
2850 EmitCheck(std::make_pair(CheckResult, SanitizerKind::CFIVCall),
2851 SanitizerHandler::CFICheckFail, {}, {});
2852 }
2853
2854 return Builder.CreateBitCast(
2855 Builder.CreateExtractValue(CheckedLoad, 0),
2856 cast<llvm::PointerType>(VTable->getType())->getElementType());
2857 }
2858
EmitForwardingCallToLambda(const CXXMethodDecl * callOperator,CallArgList & callArgs)2859 void CodeGenFunction::EmitForwardingCallToLambda(
2860 const CXXMethodDecl *callOperator,
2861 CallArgList &callArgs) {
2862 // Get the address of the call operator.
2863 const CGFunctionInfo &calleeFnInfo =
2864 CGM.getTypes().arrangeCXXMethodDeclaration(callOperator);
2865 llvm::Constant *calleePtr =
2866 CGM.GetAddrOfFunction(GlobalDecl(callOperator),
2867 CGM.getTypes().GetFunctionType(calleeFnInfo));
2868
2869 // Prepare the return slot.
2870 const FunctionProtoType *FPT =
2871 callOperator->getType()->castAs<FunctionProtoType>();
2872 QualType resultType = FPT->getReturnType();
2873 ReturnValueSlot returnSlot;
2874 if (!resultType->isVoidType() &&
2875 calleeFnInfo.getReturnInfo().getKind() == ABIArgInfo::Indirect &&
2876 !hasScalarEvaluationKind(calleeFnInfo.getReturnType()))
2877 returnSlot =
2878 ReturnValueSlot(ReturnValue, resultType.isVolatileQualified(),
2879 /*IsUnused=*/false, /*IsExternallyDestructed=*/true);
2880
2881 // We don't need to separately arrange the call arguments because
2882 // the call can't be variadic anyway --- it's impossible to forward
2883 // variadic arguments.
2884
2885 // Now emit our call.
2886 auto callee = CGCallee::forDirect(calleePtr, GlobalDecl(callOperator));
2887 RValue RV = EmitCall(calleeFnInfo, callee, returnSlot, callArgs);
2888
2889 // If necessary, copy the returned value into the slot.
2890 if (!resultType->isVoidType() && returnSlot.isNull()) {
2891 if (getLangOpts().ObjCAutoRefCount && resultType->isObjCRetainableType()) {
2892 RV = RValue::get(EmitARCRetainAutoreleasedReturnValue(RV.getScalarVal()));
2893 }
2894 EmitReturnOfRValue(RV, resultType);
2895 } else
2896 EmitBranchThroughCleanup(ReturnBlock);
2897 }
2898
EmitLambdaBlockInvokeBody()2899 void CodeGenFunction::EmitLambdaBlockInvokeBody() {
2900 const BlockDecl *BD = BlockInfo->getBlockDecl();
2901 const VarDecl *variable = BD->capture_begin()->getVariable();
2902 const CXXRecordDecl *Lambda = variable->getType()->getAsCXXRecordDecl();
2903 const CXXMethodDecl *CallOp = Lambda->getLambdaCallOperator();
2904
2905 if (CallOp->isVariadic()) {
2906 // FIXME: Making this work correctly is nasty because it requires either
2907 // cloning the body of the call operator or making the call operator
2908 // forward.
2909 CGM.ErrorUnsupported(CurCodeDecl, "lambda conversion to variadic function");
2910 return;
2911 }
2912
2913 // Start building arguments for forwarding call
2914 CallArgList CallArgs;
2915
2916 QualType ThisType = getContext().getPointerType(getContext().getRecordType(Lambda));
2917 Address ThisPtr = GetAddrOfBlockDecl(variable);
2918 CallArgs.add(RValue::get(ThisPtr.getPointer()), ThisType);
2919
2920 // Add the rest of the parameters.
2921 for (auto param : BD->parameters())
2922 EmitDelegateCallArg(CallArgs, param, param->getBeginLoc());
2923
2924 assert(!Lambda->isGenericLambda() &&
2925 "generic lambda interconversion to block not implemented");
2926 EmitForwardingCallToLambda(CallOp, CallArgs);
2927 }
2928
EmitLambdaDelegatingInvokeBody(const CXXMethodDecl * MD)2929 void CodeGenFunction::EmitLambdaDelegatingInvokeBody(const CXXMethodDecl *MD) {
2930 const CXXRecordDecl *Lambda = MD->getParent();
2931
2932 // Start building arguments for forwarding call
2933 CallArgList CallArgs;
2934
2935 QualType ThisType = getContext().getPointerType(getContext().getRecordType(Lambda));
2936 llvm::Value *ThisPtr = llvm::UndefValue::get(getTypes().ConvertType(ThisType));
2937 CallArgs.add(RValue::get(ThisPtr), ThisType);
2938
2939 // Add the rest of the parameters.
2940 for (auto Param : MD->parameters())
2941 EmitDelegateCallArg(CallArgs, Param, Param->getBeginLoc());
2942
2943 const CXXMethodDecl *CallOp = Lambda->getLambdaCallOperator();
2944 // For a generic lambda, find the corresponding call operator specialization
2945 // to which the call to the static-invoker shall be forwarded.
2946 if (Lambda->isGenericLambda()) {
2947 assert(MD->isFunctionTemplateSpecialization());
2948 const TemplateArgumentList *TAL = MD->getTemplateSpecializationArgs();
2949 FunctionTemplateDecl *CallOpTemplate = CallOp->getDescribedFunctionTemplate();
2950 void *InsertPos = nullptr;
2951 FunctionDecl *CorrespondingCallOpSpecialization =
2952 CallOpTemplate->findSpecialization(TAL->asArray(), InsertPos);
2953 assert(CorrespondingCallOpSpecialization);
2954 CallOp = cast<CXXMethodDecl>(CorrespondingCallOpSpecialization);
2955 }
2956 EmitForwardingCallToLambda(CallOp, CallArgs);
2957 }
2958
EmitLambdaStaticInvokeBody(const CXXMethodDecl * MD)2959 void CodeGenFunction::EmitLambdaStaticInvokeBody(const CXXMethodDecl *MD) {
2960 if (MD->isVariadic()) {
2961 // FIXME: Making this work correctly is nasty because it requires either
2962 // cloning the body of the call operator or making the call operator forward.
2963 CGM.ErrorUnsupported(MD, "lambda conversion to variadic function");
2964 return;
2965 }
2966
2967 EmitLambdaDelegatingInvokeBody(MD);
2968 }
2969