1 //===--- CGExprAgg.cpp - Emit LLVM Code from Aggregate Expressions --------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This contains code to emit Aggregate Expr nodes as LLVM code.
12 //===----------------------------------------------------------------------===//
14 #include "CodeGenFunction.h"
15 #include "CodeGenModule.h"
16 #include "CGObjCRuntime.h"
17 #include "clang/AST/ASTContext.h"
18 #include "clang/AST/DeclCXX.h"
19 #include "clang/AST/DeclTemplate.h"
20 #include "clang/AST/StmtVisitor.h"
21 #include "llvm/Constants.h"
22 #include "llvm/Function.h"
23 #include "llvm/GlobalVariable.h"
24 #include "llvm/Intrinsics.h"
25 using namespace clang;
26 using namespace CodeGen;
28 //===----------------------------------------------------------------------===//
29 // Aggregate Expression Emitter
30 //===----------------------------------------------------------------------===//
33 class AggExprEmitter : public StmtVisitor<AggExprEmitter> {
38 /// We want to use 'dest' as the return slot except under two
40 /// - The destination slot requires garbage collection, so we
41 /// need to use the GC API.
42 /// - The destination slot is potentially aliased.
43 bool shouldUseDestForReturnSlot() const {
44 return !(Dest.requiresGCollection() || Dest.isPotentiallyAliased());
47 ReturnValueSlot getReturnValueSlot() const {
48 if (!shouldUseDestForReturnSlot())
49 return ReturnValueSlot();
51 return ReturnValueSlot(Dest.getAddr(), Dest.isVolatile());
54 AggValueSlot EnsureSlot(QualType T) {
55 if (!Dest.isIgnored()) return Dest;
56 return CGF.CreateAggTemp(T, "agg.tmp.ensured");
58 void EnsureDest(QualType T) {
59 if (!Dest.isIgnored()) return;
60 Dest = CGF.CreateAggTemp(T, "agg.tmp.ensured");
64 AggExprEmitter(CodeGenFunction &cgf, AggValueSlot Dest)
65 : CGF(cgf), Builder(CGF.Builder), Dest(Dest) {
68 //===--------------------------------------------------------------------===//
70 //===--------------------------------------------------------------------===//
72 /// EmitAggLoadOfLValue - Given an expression with aggregate type that
73 /// represents a value lvalue, this method emits the address of the lvalue,
74 /// then loads the result into DestPtr.
75 void EmitAggLoadOfLValue(const Expr *E);
77 /// EmitFinalDestCopy - Perform the final copy to DestPtr, if desired.
78 void EmitFinalDestCopy(QualType type, const LValue &src);
79 void EmitFinalDestCopy(QualType type, RValue src,
80 CharUnits srcAlignment = CharUnits::Zero());
81 void EmitCopy(QualType type, const AggValueSlot &dest,
82 const AggValueSlot &src);
84 void EmitMoveFromReturnSlot(const Expr *E, RValue Src);
86 void EmitStdInitializerList(llvm::Value *DestPtr, InitListExpr *InitList);
87 void EmitArrayInit(llvm::Value *DestPtr, llvm::ArrayType *AType,
88 QualType elementType, InitListExpr *E);
90 AggValueSlot::NeedsGCBarriers_t needsGC(QualType T) {
91 if (CGF.getLangOpts().getGC() && TypeRequiresGCollection(T))
92 return AggValueSlot::NeedsGCBarriers;
93 return AggValueSlot::DoesNotNeedGCBarriers;
96 bool TypeRequiresGCollection(QualType T);
98 //===--------------------------------------------------------------------===//
100 //===--------------------------------------------------------------------===//
102 void VisitStmt(Stmt *S) {
103 CGF.ErrorUnsupported(S, "aggregate expression");
105 void VisitParenExpr(ParenExpr *PE) { Visit(PE->getSubExpr()); }
106 void VisitGenericSelectionExpr(GenericSelectionExpr *GE) {
107 Visit(GE->getResultExpr());
109 void VisitUnaryExtension(UnaryOperator *E) { Visit(E->getSubExpr()); }
110 void VisitSubstNonTypeTemplateParmExpr(SubstNonTypeTemplateParmExpr *E) {
111 return Visit(E->getReplacement());
115 void VisitDeclRefExpr(DeclRefExpr *E) {
116 // For aggregates, we should always be able to emit the variable
117 // as an l-value unless it's a reference. This is due to the fact
118 // that we can't actually ever see a normal l2r conversion on an
119 // aggregate in C++, and in C there's no language standard
120 // actively preventing us from listing variables in the captures
122 if (E->getDecl()->getType()->isReferenceType()) {
123 if (CodeGenFunction::ConstantEmission result
124 = CGF.tryEmitAsConstant(E)) {
125 EmitFinalDestCopy(E->getType(), result.getReferenceLValue(CGF, E));
130 EmitAggLoadOfLValue(E);
133 void VisitMemberExpr(MemberExpr *ME) { EmitAggLoadOfLValue(ME); }
134 void VisitUnaryDeref(UnaryOperator *E) { EmitAggLoadOfLValue(E); }
135 void VisitStringLiteral(StringLiteral *E) { EmitAggLoadOfLValue(E); }
136 void VisitCompoundLiteralExpr(CompoundLiteralExpr *E);
137 void VisitArraySubscriptExpr(ArraySubscriptExpr *E) {
138 EmitAggLoadOfLValue(E);
140 void VisitPredefinedExpr(const PredefinedExpr *E) {
141 EmitAggLoadOfLValue(E);
145 void VisitCastExpr(CastExpr *E);
146 void VisitCallExpr(const CallExpr *E);
147 void VisitStmtExpr(const StmtExpr *E);
148 void VisitBinaryOperator(const BinaryOperator *BO);
149 void VisitPointerToDataMemberBinaryOperator(const BinaryOperator *BO);
150 void VisitBinAssign(const BinaryOperator *E);
151 void VisitBinComma(const BinaryOperator *E);
153 void VisitObjCMessageExpr(ObjCMessageExpr *E);
154 void VisitObjCIvarRefExpr(ObjCIvarRefExpr *E) {
155 EmitAggLoadOfLValue(E);
158 void VisitAbstractConditionalOperator(const AbstractConditionalOperator *CO);
159 void VisitChooseExpr(const ChooseExpr *CE);
160 void VisitInitListExpr(InitListExpr *E);
161 void VisitImplicitValueInitExpr(ImplicitValueInitExpr *E);
162 void VisitCXXDefaultArgExpr(CXXDefaultArgExpr *DAE) {
163 Visit(DAE->getExpr());
165 void VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E);
166 void VisitCXXConstructExpr(const CXXConstructExpr *E);
167 void VisitLambdaExpr(LambdaExpr *E);
168 void VisitExprWithCleanups(ExprWithCleanups *E);
169 void VisitCXXScalarValueInitExpr(CXXScalarValueInitExpr *E);
170 void VisitCXXTypeidExpr(CXXTypeidExpr *E) { EmitAggLoadOfLValue(E); }
171 void VisitMaterializeTemporaryExpr(MaterializeTemporaryExpr *E);
172 void VisitOpaqueValueExpr(OpaqueValueExpr *E);
174 void VisitPseudoObjectExpr(PseudoObjectExpr *E) {
175 if (E->isGLValue()) {
176 LValue LV = CGF.EmitPseudoObjectLValue(E);
177 return EmitFinalDestCopy(E->getType(), LV);
180 CGF.EmitPseudoObjectRValue(E, EnsureSlot(E->getType()));
183 void VisitVAArgExpr(VAArgExpr *E);
185 void EmitInitializationToLValue(Expr *E, LValue Address);
186 void EmitNullInitializationToLValue(LValue Address);
187 // case Expr::ChooseExprClass:
188 void VisitCXXThrowExpr(const CXXThrowExpr *E) { CGF.EmitCXXThrowExpr(E); }
189 void VisitAtomicExpr(AtomicExpr *E) {
190 CGF.EmitAtomicExpr(E, EnsureSlot(E->getType()).getAddr());
193 } // end anonymous namespace.
195 //===----------------------------------------------------------------------===//
197 //===----------------------------------------------------------------------===//
199 /// EmitAggLoadOfLValue - Given an expression with aggregate type that
200 /// represents a value lvalue, this method emits the address of the lvalue,
201 /// then loads the result into DestPtr.
202 void AggExprEmitter::EmitAggLoadOfLValue(const Expr *E) {
203 LValue LV = CGF.EmitLValue(E);
204 EmitFinalDestCopy(E->getType(), LV);
207 /// \brief True if the given aggregate type requires special GC API calls.
208 bool AggExprEmitter::TypeRequiresGCollection(QualType T) {
209 // Only record types have members that might require garbage collection.
210 const RecordType *RecordTy = T->getAs<RecordType>();
211 if (!RecordTy) return false;
213 // Don't mess with non-trivial C++ types.
214 RecordDecl *Record = RecordTy->getDecl();
215 if (isa<CXXRecordDecl>(Record) &&
216 (!cast<CXXRecordDecl>(Record)->hasTrivialCopyConstructor() ||
217 !cast<CXXRecordDecl>(Record)->hasTrivialDestructor()))
220 // Check whether the type has an object member.
221 return Record->hasObjectMember();
224 /// \brief Perform the final move to DestPtr if for some reason
225 /// getReturnValueSlot() didn't use it directly.
227 /// The idea is that you do something like this:
228 /// RValue Result = EmitSomething(..., getReturnValueSlot());
229 /// EmitMoveFromReturnSlot(E, Result);
231 /// If nothing interferes, this will cause the result to be emitted
232 /// directly into the return value slot. Otherwise, a final move
233 /// will be performed.
234 void AggExprEmitter::EmitMoveFromReturnSlot(const Expr *E, RValue src) {
235 if (shouldUseDestForReturnSlot()) {
236 // Logically, Dest.getAddr() should equal Src.getAggregateAddr().
237 // The possibility of undef rvalues complicates that a lot,
238 // though, so we can't really assert.
242 // Otherwise, copy from there to the destination.
243 assert(Dest.getAddr() != src.getAggregateAddr());
244 std::pair<CharUnits, CharUnits> typeInfo =
245 CGF.getContext().getTypeInfoInChars(E->getType());
246 EmitFinalDestCopy(E->getType(), src, typeInfo.second);
249 /// EmitFinalDestCopy - Perform the final copy to DestPtr, if desired.
250 void AggExprEmitter::EmitFinalDestCopy(QualType type, RValue src,
251 CharUnits srcAlign) {
252 assert(src.isAggregate() && "value must be aggregate value!");
253 LValue srcLV = CGF.MakeAddrLValue(src.getAggregateAddr(), type, srcAlign);
254 EmitFinalDestCopy(type, srcLV);
257 /// EmitFinalDestCopy - Perform the final copy to DestPtr, if desired.
258 void AggExprEmitter::EmitFinalDestCopy(QualType type, const LValue &src) {
259 // If Dest is ignored, then we're evaluating an aggregate expression
260 // in a context that doesn't care about the result. Note that loads
261 // from volatile l-values force the existence of a non-ignored
263 if (Dest.isIgnored())
266 AggValueSlot srcAgg =
267 AggValueSlot::forLValue(src, AggValueSlot::IsDestructed,
268 needsGC(type), AggValueSlot::IsAliased);
269 EmitCopy(type, Dest, srcAgg);
272 /// Perform a copy from the source into the destination.
274 /// \param type - the type of the aggregate being copied; qualifiers are
276 void AggExprEmitter::EmitCopy(QualType type, const AggValueSlot &dest,
277 const AggValueSlot &src) {
278 if (dest.requiresGCollection()) {
279 CharUnits sz = CGF.getContext().getTypeSizeInChars(type);
280 llvm::Value *size = llvm::ConstantInt::get(CGF.SizeTy, sz.getQuantity());
281 CGF.CGM.getObjCRuntime().EmitGCMemmoveCollectable(CGF,
288 // If the result of the assignment is used, copy the LHS there also.
289 // It's volatile if either side is. Use the minimum alignment of
291 CGF.EmitAggregateCopy(dest.getAddr(), src.getAddr(), type,
292 dest.isVolatile() || src.isVolatile(),
293 std::min(dest.getAlignment(), src.getAlignment()));
296 static QualType GetStdInitializerListElementType(QualType T) {
297 // Just assume that this is really std::initializer_list.
298 ClassTemplateSpecializationDecl *specialization =
299 cast<ClassTemplateSpecializationDecl>(T->castAs<RecordType>()->getDecl());
300 return specialization->getTemplateArgs()[0].getAsType();
303 /// \brief Prepare cleanup for the temporary array.
304 static void EmitStdInitializerListCleanup(CodeGenFunction &CGF,
307 const InitListExpr *initList) {
308 QualType::DestructionKind dtorKind = arrayType.isDestructedType();
310 return; // Type doesn't need destroying.
311 if (dtorKind != QualType::DK_cxx_destructor) {
312 CGF.ErrorUnsupported(initList, "ObjC ARC type in initializer_list");
316 CodeGenFunction::Destroyer *destroyer = CGF.getDestroyer(dtorKind);
317 CGF.pushDestroy(NormalAndEHCleanup, addr, arrayType, destroyer,
321 /// \brief Emit the initializer for a std::initializer_list initialized with a
322 /// real initializer list.
323 void AggExprEmitter::EmitStdInitializerList(llvm::Value *destPtr,
324 InitListExpr *initList) {
325 // We emit an array containing the elements, then have the init list point
327 ASTContext &ctx = CGF.getContext();
328 unsigned numInits = initList->getNumInits();
329 QualType element = GetStdInitializerListElementType(initList->getType());
330 llvm::APInt size(ctx.getTypeSize(ctx.getSizeType()), numInits);
331 QualType array = ctx.getConstantArrayType(element, size, ArrayType::Normal,0);
332 llvm::Type *LTy = CGF.ConvertTypeForMem(array);
333 llvm::AllocaInst *alloc = CGF.CreateTempAlloca(LTy);
334 alloc->setAlignment(ctx.getTypeAlignInChars(array).getQuantity());
335 alloc->setName(".initlist.");
337 EmitArrayInit(alloc, cast<llvm::ArrayType>(LTy), element, initList);
339 // FIXME: The diagnostics are somewhat out of place here.
340 RecordDecl *record = initList->getType()->castAs<RecordType>()->getDecl();
341 RecordDecl::field_iterator field = record->field_begin();
342 if (field == record->field_end()) {
343 CGF.ErrorUnsupported(initList, "weird std::initializer_list");
347 QualType elementPtr = ctx.getPointerType(element.withConst());
350 if (!ctx.hasSameType(field->getType(), elementPtr)) {
351 CGF.ErrorUnsupported(initList, "weird std::initializer_list");
354 LValue DestLV = CGF.MakeNaturalAlignAddrLValue(destPtr, initList->getType());
355 LValue start = CGF.EmitLValueForFieldInitialization(DestLV, *field);
356 llvm::Value *arrayStart = Builder.CreateStructGEP(alloc, 0, "arraystart");
357 CGF.EmitStoreThroughLValue(RValue::get(arrayStart), start);
360 if (field == record->field_end()) {
361 CGF.ErrorUnsupported(initList, "weird std::initializer_list");
364 LValue endOrLength = CGF.EmitLValueForFieldInitialization(DestLV, *field);
365 if (ctx.hasSameType(field->getType(), elementPtr)) {
367 llvm::Value *arrayEnd = Builder.CreateStructGEP(alloc,numInits, "arrayend");
368 CGF.EmitStoreThroughLValue(RValue::get(arrayEnd), endOrLength);
369 } else if(ctx.hasSameType(field->getType(), ctx.getSizeType())) {
371 CGF.EmitStoreThroughLValue(RValue::get(Builder.getInt(size)), endOrLength);
373 CGF.ErrorUnsupported(initList, "weird std::initializer_list");
377 if (!Dest.isExternallyDestructed())
378 EmitStdInitializerListCleanup(CGF, array, alloc, initList);
381 /// \brief Emit initialization of an array from an initializer list.
382 void AggExprEmitter::EmitArrayInit(llvm::Value *DestPtr, llvm::ArrayType *AType,
383 QualType elementType, InitListExpr *E) {
384 uint64_t NumInitElements = E->getNumInits();
386 uint64_t NumArrayElements = AType->getNumElements();
387 assert(NumInitElements <= NumArrayElements);
389 // DestPtr is an array*. Construct an elementType* by drilling
391 llvm::Value *zero = llvm::ConstantInt::get(CGF.SizeTy, 0);
392 llvm::Value *indices[] = { zero, zero };
394 Builder.CreateInBoundsGEP(DestPtr, indices, "arrayinit.begin");
396 // Exception safety requires us to destroy all the
397 // already-constructed members if an initializer throws.
398 // For that, we'll need an EH cleanup.
399 QualType::DestructionKind dtorKind = elementType.isDestructedType();
400 llvm::AllocaInst *endOfInit = 0;
401 EHScopeStack::stable_iterator cleanup;
402 llvm::Instruction *cleanupDominator = 0;
403 if (CGF.needsEHCleanup(dtorKind)) {
404 // In principle we could tell the cleanup where we are more
405 // directly, but the control flow can get so varied here that it
406 // would actually be quite complex. Therefore we go through an
408 endOfInit = CGF.CreateTempAlloca(begin->getType(),
409 "arrayinit.endOfInit");
410 cleanupDominator = Builder.CreateStore(begin, endOfInit);
411 CGF.pushIrregularPartialArrayCleanup(begin, endOfInit, elementType,
412 CGF.getDestroyer(dtorKind));
413 cleanup = CGF.EHStack.stable_begin();
415 // Otherwise, remember that we didn't need a cleanup.
417 dtorKind = QualType::DK_none;
420 llvm::Value *one = llvm::ConstantInt::get(CGF.SizeTy, 1);
422 // The 'current element to initialize'. The invariants on this
423 // variable are complicated. Essentially, after each iteration of
424 // the loop, it points to the last initialized element, except
425 // that it points to the beginning of the array before any
426 // elements have been initialized.
427 llvm::Value *element = begin;
429 // Emit the explicit initializers.
430 for (uint64_t i = 0; i != NumInitElements; ++i) {
431 // Advance to the next element.
433 element = Builder.CreateInBoundsGEP(element, one, "arrayinit.element");
435 // Tell the cleanup that it needs to destroy up to this
436 // element. TODO: some of these stores can be trivially
437 // observed to be unnecessary.
438 if (endOfInit) Builder.CreateStore(element, endOfInit);
441 // If these are nested std::initializer_list inits, do them directly,
442 // because they are conceptually the same "location".
443 InitListExpr *initList = dyn_cast<InitListExpr>(E->getInit(i));
444 if (initList && initList->initializesStdInitializerList()) {
445 EmitStdInitializerList(element, initList);
447 LValue elementLV = CGF.MakeAddrLValue(element, elementType);
448 EmitInitializationToLValue(E->getInit(i), elementLV);
452 // Check whether there's a non-trivial array-fill expression.
453 // Note that this will be a CXXConstructExpr even if the element
454 // type is an array (or array of array, etc.) of class type.
455 Expr *filler = E->getArrayFiller();
456 bool hasTrivialFiller = true;
457 if (CXXConstructExpr *cons = dyn_cast_or_null<CXXConstructExpr>(filler)) {
458 assert(cons->getConstructor()->isDefaultConstructor());
459 hasTrivialFiller = cons->getConstructor()->isTrivial();
462 // Any remaining elements need to be zero-initialized, possibly
463 // using the filler expression. We can skip this if the we're
464 // emitting to zeroed memory.
465 if (NumInitElements != NumArrayElements &&
466 !(Dest.isZeroed() && hasTrivialFiller &&
467 CGF.getTypes().isZeroInitializable(elementType))) {
469 // Use an actual loop. This is basically
470 // do { *array++ = filler; } while (array != end);
472 // Advance to the start of the rest of the array.
473 if (NumInitElements) {
474 element = Builder.CreateInBoundsGEP(element, one, "arrayinit.start");
475 if (endOfInit) Builder.CreateStore(element, endOfInit);
478 // Compute the end of the array.
479 llvm::Value *end = Builder.CreateInBoundsGEP(begin,
480 llvm::ConstantInt::get(CGF.SizeTy, NumArrayElements),
483 llvm::BasicBlock *entryBB = Builder.GetInsertBlock();
484 llvm::BasicBlock *bodyBB = CGF.createBasicBlock("arrayinit.body");
486 // Jump into the body.
487 CGF.EmitBlock(bodyBB);
488 llvm::PHINode *currentElement =
489 Builder.CreatePHI(element->getType(), 2, "arrayinit.cur");
490 currentElement->addIncoming(element, entryBB);
492 // Emit the actual filler expression.
493 LValue elementLV = CGF.MakeAddrLValue(currentElement, elementType);
495 EmitInitializationToLValue(filler, elementLV);
497 EmitNullInitializationToLValue(elementLV);
499 // Move on to the next element.
500 llvm::Value *nextElement =
501 Builder.CreateInBoundsGEP(currentElement, one, "arrayinit.next");
503 // Tell the EH cleanup that we finished with the last element.
504 if (endOfInit) Builder.CreateStore(nextElement, endOfInit);
506 // Leave the loop if we're done.
507 llvm::Value *done = Builder.CreateICmpEQ(nextElement, end,
509 llvm::BasicBlock *endBB = CGF.createBasicBlock("arrayinit.end");
510 Builder.CreateCondBr(done, endBB, bodyBB);
511 currentElement->addIncoming(nextElement, Builder.GetInsertBlock());
513 CGF.EmitBlock(endBB);
516 // Leave the partial-array cleanup if we entered one.
517 if (dtorKind) CGF.DeactivateCleanupBlock(cleanup, cleanupDominator);
520 //===----------------------------------------------------------------------===//
522 //===----------------------------------------------------------------------===//
524 void AggExprEmitter::VisitMaterializeTemporaryExpr(MaterializeTemporaryExpr *E){
525 Visit(E->GetTemporaryExpr());
528 void AggExprEmitter::VisitOpaqueValueExpr(OpaqueValueExpr *e) {
529 EmitFinalDestCopy(e->getType(), CGF.getOpaqueLValueMapping(e));
533 AggExprEmitter::VisitCompoundLiteralExpr(CompoundLiteralExpr *E) {
534 if (E->getType().isPODType(CGF.getContext())) {
535 // For a POD type, just emit a load of the lvalue + a copy, because our
536 // compound literal might alias the destination.
537 // FIXME: This is a band-aid; the real problem appears to be in our handling
538 // of assignments, where we store directly into the LHS without checking
539 // whether anything in the RHS aliases.
540 EmitAggLoadOfLValue(E);
544 AggValueSlot Slot = EnsureSlot(E->getType());
545 CGF.EmitAggExpr(E->getInitializer(), Slot);
549 void AggExprEmitter::VisitCastExpr(CastExpr *E) {
550 switch (E->getCastKind()) {
552 // FIXME: Can this actually happen? We have no test coverage for it.
553 assert(isa<CXXDynamicCastExpr>(E) && "CK_Dynamic without a dynamic_cast?");
554 LValue LV = CGF.EmitCheckedLValue(E->getSubExpr(),
555 CodeGenFunction::TCK_Load);
556 // FIXME: Do we also need to handle property references here?
558 CGF.EmitDynamicCast(LV.getAddress(), cast<CXXDynamicCastExpr>(E));
560 CGF.CGM.ErrorUnsupported(E, "non-simple lvalue dynamic_cast");
562 if (!Dest.isIgnored())
563 CGF.CGM.ErrorUnsupported(E, "lvalue dynamic_cast with a destination");
568 if (Dest.isIgnored()) break;
570 // GCC union extension
571 QualType Ty = E->getSubExpr()->getType();
572 QualType PtrTy = CGF.getContext().getPointerType(Ty);
573 llvm::Value *CastPtr = Builder.CreateBitCast(Dest.getAddr(),
574 CGF.ConvertType(PtrTy));
575 EmitInitializationToLValue(E->getSubExpr(),
576 CGF.MakeAddrLValue(CastPtr, Ty));
580 case CK_DerivedToBase:
581 case CK_BaseToDerived:
582 case CK_UncheckedDerivedToBase: {
583 llvm_unreachable("cannot perform hierarchy conversion in EmitAggExpr: "
584 "should have been unpacked before we got here");
587 case CK_LValueToRValue:
588 // If we're loading from a volatile type, force the destination
590 if (E->getSubExpr()->getType().isVolatileQualified()) {
591 EnsureDest(E->getType());
592 return Visit(E->getSubExpr());
597 case CK_AtomicToNonAtomic:
598 case CK_NonAtomicToAtomic:
599 case CK_UserDefinedConversion:
600 case CK_ConstructorConversion:
601 assert(CGF.getContext().hasSameUnqualifiedType(E->getSubExpr()->getType(),
603 "Implicit cast types must be compatible");
604 Visit(E->getSubExpr());
607 case CK_LValueBitCast:
608 llvm_unreachable("should not be emitting lvalue bitcast as rvalue");
612 case CK_ArrayToPointerDecay:
613 case CK_FunctionToPointerDecay:
614 case CK_NullToPointer:
615 case CK_NullToMemberPointer:
616 case CK_BaseToDerivedMemberPointer:
617 case CK_DerivedToBaseMemberPointer:
618 case CK_MemberPointerToBoolean:
619 case CK_ReinterpretMemberPointer:
620 case CK_IntegralToPointer:
621 case CK_PointerToIntegral:
622 case CK_PointerToBoolean:
625 case CK_IntegralCast:
626 case CK_IntegralToBoolean:
627 case CK_IntegralToFloating:
628 case CK_FloatingToIntegral:
629 case CK_FloatingToBoolean:
630 case CK_FloatingCast:
631 case CK_CPointerToObjCPointerCast:
632 case CK_BlockPointerToObjCPointerCast:
633 case CK_AnyPointerToBlockPointerCast:
634 case CK_ObjCObjectLValueCast:
635 case CK_FloatingRealToComplex:
636 case CK_FloatingComplexToReal:
637 case CK_FloatingComplexToBoolean:
638 case CK_FloatingComplexCast:
639 case CK_FloatingComplexToIntegralComplex:
640 case CK_IntegralRealToComplex:
641 case CK_IntegralComplexToReal:
642 case CK_IntegralComplexToBoolean:
643 case CK_IntegralComplexCast:
644 case CK_IntegralComplexToFloatingComplex:
645 case CK_ARCProduceObject:
646 case CK_ARCConsumeObject:
647 case CK_ARCReclaimReturnedObject:
648 case CK_ARCExtendBlockObject:
649 case CK_CopyAndAutoreleaseBlockObject:
650 case CK_BuiltinFnToFnPtr:
651 llvm_unreachable("cast kind invalid for aggregate types");
655 void AggExprEmitter::VisitCallExpr(const CallExpr *E) {
656 if (E->getCallReturnType()->isReferenceType()) {
657 EmitAggLoadOfLValue(E);
661 RValue RV = CGF.EmitCallExpr(E, getReturnValueSlot());
662 EmitMoveFromReturnSlot(E, RV);
665 void AggExprEmitter::VisitObjCMessageExpr(ObjCMessageExpr *E) {
666 RValue RV = CGF.EmitObjCMessageExpr(E, getReturnValueSlot());
667 EmitMoveFromReturnSlot(E, RV);
670 void AggExprEmitter::VisitBinComma(const BinaryOperator *E) {
671 CGF.EmitIgnoredExpr(E->getLHS());
675 void AggExprEmitter::VisitStmtExpr(const StmtExpr *E) {
676 CodeGenFunction::StmtExprEvaluation eval(CGF);
677 CGF.EmitCompoundStmt(*E->getSubStmt(), true, Dest);
680 void AggExprEmitter::VisitBinaryOperator(const BinaryOperator *E) {
681 if (E->getOpcode() == BO_PtrMemD || E->getOpcode() == BO_PtrMemI)
682 VisitPointerToDataMemberBinaryOperator(E);
684 CGF.ErrorUnsupported(E, "aggregate binary expression");
687 void AggExprEmitter::VisitPointerToDataMemberBinaryOperator(
688 const BinaryOperator *E) {
689 LValue LV = CGF.EmitPointerToDataMemberBinaryExpr(E);
690 EmitFinalDestCopy(E->getType(), LV);
693 /// Is the value of the given expression possibly a reference to or
694 /// into a __block variable?
695 static bool isBlockVarRef(const Expr *E) {
696 // Make sure we look through parens.
697 E = E->IgnoreParens();
699 // Check for a direct reference to a __block variable.
700 if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E)) {
701 const VarDecl *var = dyn_cast<VarDecl>(DRE->getDecl());
702 return (var && var->hasAttr<BlocksAttr>());
705 // More complicated stuff.
708 if (const BinaryOperator *op = dyn_cast<BinaryOperator>(E)) {
709 // For an assignment or pointer-to-member operation, just care
711 if (op->isAssignmentOp() || op->isPtrMemOp())
712 return isBlockVarRef(op->getLHS());
714 // For a comma, just care about the RHS.
715 if (op->getOpcode() == BO_Comma)
716 return isBlockVarRef(op->getRHS());
718 // FIXME: pointer arithmetic?
721 // Check both sides of a conditional operator.
722 } else if (const AbstractConditionalOperator *op
723 = dyn_cast<AbstractConditionalOperator>(E)) {
724 return isBlockVarRef(op->getTrueExpr())
725 || isBlockVarRef(op->getFalseExpr());
727 // OVEs are required to support BinaryConditionalOperators.
728 } else if (const OpaqueValueExpr *op
729 = dyn_cast<OpaqueValueExpr>(E)) {
730 if (const Expr *src = op->getSourceExpr())
731 return isBlockVarRef(src);
733 // Casts are necessary to get things like (*(int*)&var) = foo().
734 // We don't really care about the kind of cast here, except
735 // we don't want to look through l2r casts, because it's okay
736 // to get the *value* in a __block variable.
737 } else if (const CastExpr *cast = dyn_cast<CastExpr>(E)) {
738 if (cast->getCastKind() == CK_LValueToRValue)
740 return isBlockVarRef(cast->getSubExpr());
742 // Handle unary operators. Again, just aggressively look through
743 // it, ignoring the operation.
744 } else if (const UnaryOperator *uop = dyn_cast<UnaryOperator>(E)) {
745 return isBlockVarRef(uop->getSubExpr());
747 // Look into the base of a field access.
748 } else if (const MemberExpr *mem = dyn_cast<MemberExpr>(E)) {
749 return isBlockVarRef(mem->getBase());
751 // Look into the base of a subscript.
752 } else if (const ArraySubscriptExpr *sub = dyn_cast<ArraySubscriptExpr>(E)) {
753 return isBlockVarRef(sub->getBase());
759 void AggExprEmitter::VisitBinAssign(const BinaryOperator *E) {
760 // For an assignment to work, the value on the right has
761 // to be compatible with the value on the left.
762 assert(CGF.getContext().hasSameUnqualifiedType(E->getLHS()->getType(),
763 E->getRHS()->getType())
764 && "Invalid assignment");
766 // If the LHS might be a __block variable, and the RHS can
767 // potentially cause a block copy, we need to evaluate the RHS first
768 // so that the assignment goes the right place.
769 // This is pretty semantically fragile.
770 if (isBlockVarRef(E->getLHS()) &&
771 E->getRHS()->HasSideEffects(CGF.getContext())) {
772 // Ensure that we have a destination, and evaluate the RHS into that.
773 EnsureDest(E->getRHS()->getType());
776 // Now emit the LHS and copy into it.
777 LValue LHS = CGF.EmitCheckedLValue(E->getLHS(), CodeGenFunction::TCK_Store);
779 EmitCopy(E->getLHS()->getType(),
780 AggValueSlot::forLValue(LHS, AggValueSlot::IsDestructed,
781 needsGC(E->getLHS()->getType()),
782 AggValueSlot::IsAliased),
787 LValue LHS = CGF.EmitLValue(E->getLHS());
789 // Codegen the RHS so that it stores directly into the LHS.
790 AggValueSlot LHSSlot =
791 AggValueSlot::forLValue(LHS, AggValueSlot::IsDestructed,
792 needsGC(E->getLHS()->getType()),
793 AggValueSlot::IsAliased);
794 CGF.EmitAggExpr(E->getRHS(), LHSSlot);
796 // Copy into the destination if the assignment isn't ignored.
797 EmitFinalDestCopy(E->getType(), LHS);
800 void AggExprEmitter::
801 VisitAbstractConditionalOperator(const AbstractConditionalOperator *E) {
802 llvm::BasicBlock *LHSBlock = CGF.createBasicBlock("cond.true");
803 llvm::BasicBlock *RHSBlock = CGF.createBasicBlock("cond.false");
804 llvm::BasicBlock *ContBlock = CGF.createBasicBlock("cond.end");
806 // Bind the common expression if necessary.
807 CodeGenFunction::OpaqueValueMapping binding(CGF, E);
809 CodeGenFunction::ConditionalEvaluation eval(CGF);
810 CGF.EmitBranchOnBoolExpr(E->getCond(), LHSBlock, RHSBlock);
812 // Save whether the destination's lifetime is externally managed.
813 bool isExternallyDestructed = Dest.isExternallyDestructed();
816 CGF.EmitBlock(LHSBlock);
817 Visit(E->getTrueExpr());
820 assert(CGF.HaveInsertPoint() && "expression evaluation ended with no IP!");
821 CGF.Builder.CreateBr(ContBlock);
823 // If the result of an agg expression is unused, then the emission
824 // of the LHS might need to create a destination slot. That's fine
825 // with us, and we can safely emit the RHS into the same slot, but
826 // we shouldn't claim that it's already being destructed.
827 Dest.setExternallyDestructed(isExternallyDestructed);
830 CGF.EmitBlock(RHSBlock);
831 Visit(E->getFalseExpr());
834 CGF.EmitBlock(ContBlock);
837 void AggExprEmitter::VisitChooseExpr(const ChooseExpr *CE) {
838 Visit(CE->getChosenSubExpr(CGF.getContext()));
841 void AggExprEmitter::VisitVAArgExpr(VAArgExpr *VE) {
842 llvm::Value *ArgValue = CGF.EmitVAListRef(VE->getSubExpr());
843 llvm::Value *ArgPtr = CGF.EmitVAArg(ArgValue, VE->getType());
846 CGF.ErrorUnsupported(VE, "aggregate va_arg expression");
850 EmitFinalDestCopy(VE->getType(), CGF.MakeAddrLValue(ArgPtr, VE->getType()));
853 void AggExprEmitter::VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E) {
854 // Ensure that we have a slot, but if we already do, remember
855 // whether it was externally destructed.
856 bool wasExternallyDestructed = Dest.isExternallyDestructed();
857 EnsureDest(E->getType());
859 // We're going to push a destructor if there isn't already one.
860 Dest.setExternallyDestructed();
862 Visit(E->getSubExpr());
864 // Push that destructor we promised.
865 if (!wasExternallyDestructed)
866 CGF.EmitCXXTemporary(E->getTemporary(), E->getType(), Dest.getAddr());
870 AggExprEmitter::VisitCXXConstructExpr(const CXXConstructExpr *E) {
871 AggValueSlot Slot = EnsureSlot(E->getType());
872 CGF.EmitCXXConstructExpr(E, Slot);
876 AggExprEmitter::VisitLambdaExpr(LambdaExpr *E) {
877 AggValueSlot Slot = EnsureSlot(E->getType());
878 CGF.EmitLambdaExpr(E, Slot);
881 void AggExprEmitter::VisitExprWithCleanups(ExprWithCleanups *E) {
882 CGF.enterFullExpression(E);
883 CodeGenFunction::RunCleanupsScope cleanups(CGF);
884 Visit(E->getSubExpr());
887 void AggExprEmitter::VisitCXXScalarValueInitExpr(CXXScalarValueInitExpr *E) {
888 QualType T = E->getType();
889 AggValueSlot Slot = EnsureSlot(T);
890 EmitNullInitializationToLValue(CGF.MakeAddrLValue(Slot.getAddr(), T));
893 void AggExprEmitter::VisitImplicitValueInitExpr(ImplicitValueInitExpr *E) {
894 QualType T = E->getType();
895 AggValueSlot Slot = EnsureSlot(T);
896 EmitNullInitializationToLValue(CGF.MakeAddrLValue(Slot.getAddr(), T));
899 /// isSimpleZero - If emitting this value will obviously just cause a store of
900 /// zero to memory, return true. This can return false if uncertain, so it just
901 /// handles simple cases.
902 static bool isSimpleZero(const Expr *E, CodeGenFunction &CGF) {
903 E = E->IgnoreParens();
906 if (const IntegerLiteral *IL = dyn_cast<IntegerLiteral>(E))
907 return IL->getValue() == 0;
909 if (const FloatingLiteral *FL = dyn_cast<FloatingLiteral>(E))
910 return FL->getValue().isPosZero();
912 if ((isa<ImplicitValueInitExpr>(E) || isa<CXXScalarValueInitExpr>(E)) &&
913 CGF.getTypes().isZeroInitializable(E->getType()))
915 // (int*)0 - Null pointer expressions.
916 if (const CastExpr *ICE = dyn_cast<CastExpr>(E))
917 return ICE->getCastKind() == CK_NullToPointer;
919 if (const CharacterLiteral *CL = dyn_cast<CharacterLiteral>(E))
920 return CL->getValue() == 0;
922 // Otherwise, hard case: conservatively return false.
928 AggExprEmitter::EmitInitializationToLValue(Expr* E, LValue LV) {
929 QualType type = LV.getType();
930 // FIXME: Ignore result?
931 // FIXME: Are initializers affected by volatile?
932 if (Dest.isZeroed() && isSimpleZero(E, CGF)) {
933 // Storing "i32 0" to a zero'd memory location is a noop.
934 } else if (isa<ImplicitValueInitExpr>(E)) {
935 EmitNullInitializationToLValue(LV);
936 } else if (type->isReferenceType()) {
937 RValue RV = CGF.EmitReferenceBindingToExpr(E, /*InitializedDecl=*/0);
938 CGF.EmitStoreThroughLValue(RV, LV);
939 } else if (type->isAnyComplexType()) {
940 CGF.EmitComplexExprIntoAddr(E, LV.getAddress(), false);
941 } else if (CGF.hasAggregateLLVMType(type)) {
942 CGF.EmitAggExpr(E, AggValueSlot::forLValue(LV,
943 AggValueSlot::IsDestructed,
944 AggValueSlot::DoesNotNeedGCBarriers,
945 AggValueSlot::IsNotAliased,
947 } else if (LV.isSimple()) {
948 CGF.EmitScalarInit(E, /*D=*/0, LV, /*Captured=*/false);
950 CGF.EmitStoreThroughLValue(RValue::get(CGF.EmitScalarExpr(E)), LV);
954 void AggExprEmitter::EmitNullInitializationToLValue(LValue lv) {
955 QualType type = lv.getType();
957 // If the destination slot is already zeroed out before the aggregate is
958 // copied into it, we don't have to emit any zeros here.
959 if (Dest.isZeroed() && CGF.getTypes().isZeroInitializable(type))
962 if (!CGF.hasAggregateLLVMType(type)) {
963 // For non-aggregates, we can store zero.
964 llvm::Value *null = llvm::Constant::getNullValue(CGF.ConvertType(type));
965 // Note that the following is not equivalent to
966 // EmitStoreThroughBitfieldLValue for ARC types.
967 if (lv.isBitField()) {
968 CGF.EmitStoreThroughBitfieldLValue(RValue::get(null), lv);
970 assert(lv.isSimple());
971 CGF.EmitStoreOfScalar(null, lv, /* isInitialization */ true);
974 // There's a potential optimization opportunity in combining
975 // memsets; that would be easy for arrays, but relatively
976 // difficult for structures with the current code.
977 CGF.EmitNullInitialization(lv.getAddress(), lv.getType());
981 void AggExprEmitter::VisitInitListExpr(InitListExpr *E) {
983 // FIXME: Assess perf here? Figure out what cases are worth optimizing here
984 // (Length of globals? Chunks of zeroed-out space?).
986 // If we can, prefer a copy from a global; this is a lot less code for long
987 // globals, and it's easier for the current optimizers to analyze.
988 if (llvm::Constant* C = CGF.CGM.EmitConstantExpr(E, E->getType(), &CGF)) {
989 llvm::GlobalVariable* GV =
990 new llvm::GlobalVariable(CGF.CGM.getModule(), C->getType(), true,
991 llvm::GlobalValue::InternalLinkage, C, "");
992 EmitFinalDestCopy(E->getType(), CGF.MakeAddrLValue(GV, E->getType()));
996 if (E->hadArrayRangeDesignator())
997 CGF.ErrorUnsupported(E, "GNU array range designator extension");
999 if (E->initializesStdInitializerList()) {
1000 EmitStdInitializerList(Dest.getAddr(), E);
1004 AggValueSlot Dest = EnsureSlot(E->getType());
1005 LValue DestLV = CGF.MakeAddrLValue(Dest.getAddr(), E->getType(),
1006 Dest.getAlignment());
1008 // Handle initialization of an array.
1009 if (E->getType()->isArrayType()) {
1010 if (E->isStringLiteralInit())
1011 return Visit(E->getInit(0));
1013 QualType elementType =
1014 CGF.getContext().getAsArrayType(E->getType())->getElementType();
1016 llvm::PointerType *APType =
1017 cast<llvm::PointerType>(Dest.getAddr()->getType());
1018 llvm::ArrayType *AType =
1019 cast<llvm::ArrayType>(APType->getElementType());
1021 EmitArrayInit(Dest.getAddr(), AType, elementType, E);
1025 assert(E->getType()->isRecordType() && "Only support structs/unions here!");
1027 // Do struct initialization; this code just sets each individual member
1028 // to the approprate value. This makes bitfield support automatic;
1029 // the disadvantage is that the generated code is more difficult for
1030 // the optimizer, especially with bitfields.
1031 unsigned NumInitElements = E->getNumInits();
1032 RecordDecl *record = E->getType()->castAs<RecordType>()->getDecl();
1034 if (record->isUnion()) {
1035 // Only initialize one field of a union. The field itself is
1036 // specified by the initializer list.
1037 if (!E->getInitializedFieldInUnion()) {
1038 // Empty union; we have nothing to do.
1041 // Make sure that it's really an empty and not a failure of
1042 // semantic analysis.
1043 for (RecordDecl::field_iterator Field = record->field_begin(),
1044 FieldEnd = record->field_end();
1045 Field != FieldEnd; ++Field)
1046 assert(Field->isUnnamedBitfield() && "Only unnamed bitfields allowed");
1051 // FIXME: volatility
1052 FieldDecl *Field = E->getInitializedFieldInUnion();
1054 LValue FieldLoc = CGF.EmitLValueForFieldInitialization(DestLV, Field);
1055 if (NumInitElements) {
1056 // Store the initializer into the field
1057 EmitInitializationToLValue(E->getInit(0), FieldLoc);
1059 // Default-initialize to null.
1060 EmitNullInitializationToLValue(FieldLoc);
1066 // We'll need to enter cleanup scopes in case any of the member
1067 // initializers throw an exception.
1068 SmallVector<EHScopeStack::stable_iterator, 16> cleanups;
1069 llvm::Instruction *cleanupDominator = 0;
1071 // Here we iterate over the fields; this makes it simpler to both
1072 // default-initialize fields and skip over unnamed fields.
1073 unsigned curInitIndex = 0;
1074 for (RecordDecl::field_iterator field = record->field_begin(),
1075 fieldEnd = record->field_end();
1076 field != fieldEnd; ++field) {
1077 // We're done once we hit the flexible array member.
1078 if (field->getType()->isIncompleteArrayType())
1081 // Always skip anonymous bitfields.
1082 if (field->isUnnamedBitfield())
1085 // We're done if we reach the end of the explicit initializers, we
1086 // have a zeroed object, and the rest of the fields are
1087 // zero-initializable.
1088 if (curInitIndex == NumInitElements && Dest.isZeroed() &&
1089 CGF.getTypes().isZeroInitializable(E->getType()))
1093 LValue LV = CGF.EmitLValueForFieldInitialization(DestLV, *field);
1094 // We never generate write-barries for initialized fields.
1097 if (curInitIndex < NumInitElements) {
1098 // Store the initializer into the field.
1099 EmitInitializationToLValue(E->getInit(curInitIndex++), LV);
1101 // We're out of initalizers; default-initialize to null
1102 EmitNullInitializationToLValue(LV);
1105 // Push a destructor if necessary.
1106 // FIXME: if we have an array of structures, all explicitly
1107 // initialized, we can end up pushing a linear number of cleanups.
1108 bool pushedCleanup = false;
1109 if (QualType::DestructionKind dtorKind
1110 = field->getType().isDestructedType()) {
1111 assert(LV.isSimple());
1112 if (CGF.needsEHCleanup(dtorKind)) {
1113 if (!cleanupDominator)
1114 cleanupDominator = CGF.Builder.CreateUnreachable(); // placeholder
1116 CGF.pushDestroy(EHCleanup, LV.getAddress(), field->getType(),
1117 CGF.getDestroyer(dtorKind), false);
1118 cleanups.push_back(CGF.EHStack.stable_begin());
1119 pushedCleanup = true;
1123 // If the GEP didn't get used because of a dead zero init or something
1124 // else, clean it up for -O0 builds and general tidiness.
1125 if (!pushedCleanup && LV.isSimple())
1126 if (llvm::GetElementPtrInst *GEP =
1127 dyn_cast<llvm::GetElementPtrInst>(LV.getAddress()))
1128 if (GEP->use_empty())
1129 GEP->eraseFromParent();
1132 // Deactivate all the partial cleanups in reverse order, which
1133 // generally means popping them.
1134 for (unsigned i = cleanups.size(); i != 0; --i)
1135 CGF.DeactivateCleanupBlock(cleanups[i-1], cleanupDominator);
1137 // Destroy the placeholder if we made one.
1138 if (cleanupDominator)
1139 cleanupDominator->eraseFromParent();
1142 //===----------------------------------------------------------------------===//
1143 // Entry Points into this File
1144 //===----------------------------------------------------------------------===//
1146 /// GetNumNonZeroBytesInInit - Get an approximate count of the number of
1147 /// non-zero bytes that will be stored when outputting the initializer for the
1148 /// specified initializer expression.
1149 static CharUnits GetNumNonZeroBytesInInit(const Expr *E, CodeGenFunction &CGF) {
1150 E = E->IgnoreParens();
1152 // 0 and 0.0 won't require any non-zero stores!
1153 if (isSimpleZero(E, CGF)) return CharUnits::Zero();
1155 // If this is an initlist expr, sum up the size of sizes of the (present)
1156 // elements. If this is something weird, assume the whole thing is non-zero.
1157 const InitListExpr *ILE = dyn_cast<InitListExpr>(E);
1158 if (ILE == 0 || !CGF.getTypes().isZeroInitializable(ILE->getType()))
1159 return CGF.getContext().getTypeSizeInChars(E->getType());
1161 // InitListExprs for structs have to be handled carefully. If there are
1162 // reference members, we need to consider the size of the reference, not the
1163 // referencee. InitListExprs for unions and arrays can't have references.
1164 if (const RecordType *RT = E->getType()->getAs<RecordType>()) {
1165 if (!RT->isUnionType()) {
1166 RecordDecl *SD = E->getType()->getAs<RecordType>()->getDecl();
1167 CharUnits NumNonZeroBytes = CharUnits::Zero();
1169 unsigned ILEElement = 0;
1170 for (RecordDecl::field_iterator Field = SD->field_begin(),
1171 FieldEnd = SD->field_end(); Field != FieldEnd; ++Field) {
1172 // We're done once we hit the flexible array member or run out of
1173 // InitListExpr elements.
1174 if (Field->getType()->isIncompleteArrayType() ||
1175 ILEElement == ILE->getNumInits())
1177 if (Field->isUnnamedBitfield())
1180 const Expr *E = ILE->getInit(ILEElement++);
1182 // Reference values are always non-null and have the width of a pointer.
1183 if (Field->getType()->isReferenceType())
1184 NumNonZeroBytes += CGF.getContext().toCharUnitsFromBits(
1185 CGF.getContext().getTargetInfo().getPointerWidth(0));
1187 NumNonZeroBytes += GetNumNonZeroBytesInInit(E, CGF);
1190 return NumNonZeroBytes;
1195 CharUnits NumNonZeroBytes = CharUnits::Zero();
1196 for (unsigned i = 0, e = ILE->getNumInits(); i != e; ++i)
1197 NumNonZeroBytes += GetNumNonZeroBytesInInit(ILE->getInit(i), CGF);
1198 return NumNonZeroBytes;
1201 /// CheckAggExprForMemSetUse - If the initializer is large and has a lot of
1202 /// zeros in it, emit a memset and avoid storing the individual zeros.
1204 static void CheckAggExprForMemSetUse(AggValueSlot &Slot, const Expr *E,
1205 CodeGenFunction &CGF) {
1206 // If the slot is already known to be zeroed, nothing to do. Don't mess with
1208 if (Slot.isZeroed() || Slot.isVolatile() || Slot.getAddr() == 0) return;
1210 // C++ objects with a user-declared constructor don't need zero'ing.
1211 if (CGF.getLangOpts().CPlusPlus)
1212 if (const RecordType *RT = CGF.getContext()
1213 .getBaseElementType(E->getType())->getAs<RecordType>()) {
1214 const CXXRecordDecl *RD = cast<CXXRecordDecl>(RT->getDecl());
1215 if (RD->hasUserDeclaredConstructor())
1219 // If the type is 16-bytes or smaller, prefer individual stores over memset.
1220 std::pair<CharUnits, CharUnits> TypeInfo =
1221 CGF.getContext().getTypeInfoInChars(E->getType());
1222 if (TypeInfo.first <= CharUnits::fromQuantity(16))
1225 // Check to see if over 3/4 of the initializer are known to be zero. If so,
1226 // we prefer to emit memset + individual stores for the rest.
1227 CharUnits NumNonZeroBytes = GetNumNonZeroBytesInInit(E, CGF);
1228 if (NumNonZeroBytes*4 > TypeInfo.first)
1231 // Okay, it seems like a good idea to use an initial memset, emit the call.
1232 llvm::Constant *SizeVal = CGF.Builder.getInt64(TypeInfo.first.getQuantity());
1233 CharUnits Align = TypeInfo.second;
1235 llvm::Value *Loc = Slot.getAddr();
1237 Loc = CGF.Builder.CreateBitCast(Loc, CGF.Int8PtrTy);
1238 CGF.Builder.CreateMemSet(Loc, CGF.Builder.getInt8(0), SizeVal,
1239 Align.getQuantity(), false);
1241 // Tell the AggExprEmitter that the slot is known zero.
1248 /// EmitAggExpr - Emit the computation of the specified expression of aggregate
1249 /// type. The result is computed into DestPtr. Note that if DestPtr is null,
1250 /// the value of the aggregate expression is not needed. If VolatileDest is
1251 /// true, DestPtr cannot be 0.
1252 void CodeGenFunction::EmitAggExpr(const Expr *E, AggValueSlot Slot) {
1253 assert(E && hasAggregateLLVMType(E->getType()) &&
1254 "Invalid aggregate expression to emit");
1255 assert((Slot.getAddr() != 0 || Slot.isIgnored()) &&
1256 "slot has bits but no address");
1258 // Optimize the slot if possible.
1259 CheckAggExprForMemSetUse(Slot, E, *this);
1261 AggExprEmitter(*this, Slot).Visit(const_cast<Expr*>(E));
1264 LValue CodeGenFunction::EmitAggExprToLValue(const Expr *E) {
1265 assert(hasAggregateLLVMType(E->getType()) && "Invalid argument!");
1266 llvm::Value *Temp = CreateMemTemp(E->getType());
1267 LValue LV = MakeAddrLValue(Temp, E->getType());
1268 EmitAggExpr(E, AggValueSlot::forLValue(LV, AggValueSlot::IsNotDestructed,
1269 AggValueSlot::DoesNotNeedGCBarriers,
1270 AggValueSlot::IsNotAliased));
1274 void CodeGenFunction::EmitAggregateCopy(llvm::Value *DestPtr,
1275 llvm::Value *SrcPtr, QualType Ty,
1277 CharUnits alignment,
1278 bool isAssignment) {
1279 assert(!Ty->isAnyComplexType() && "Shouldn't happen for complex");
1281 if (getLangOpts().CPlusPlus) {
1282 if (const RecordType *RT = Ty->getAs<RecordType>()) {
1283 CXXRecordDecl *Record = cast<CXXRecordDecl>(RT->getDecl());
1284 assert((Record->hasTrivialCopyConstructor() ||
1285 Record->hasTrivialCopyAssignment() ||
1286 Record->hasTrivialMoveConstructor() ||
1287 Record->hasTrivialMoveAssignment()) &&
1288 "Trying to aggregate-copy a type without a trivial copy "
1289 "constructor or assignment operator");
1290 // Ignore empty classes in C++.
1291 if (Record->isEmpty())
1296 // Aggregate assignment turns into llvm.memcpy. This is almost valid per
1297 // C99 6.5.16.1p3, which states "If the value being stored in an object is
1298 // read from another object that overlaps in anyway the storage of the first
1299 // object, then the overlap shall be exact and the two objects shall have
1300 // qualified or unqualified versions of a compatible type."
1302 // memcpy is not defined if the source and destination pointers are exactly
1303 // equal, but other compilers do this optimization, and almost every memcpy
1304 // implementation handles this case safely. If there is a libc that does not
1305 // safely handle this, we can add a target hook.
1307 // Get data size and alignment info for this aggregate. If this is an
1308 // assignment don't copy the tail padding. Otherwise copying it is fine.
1309 std::pair<CharUnits, CharUnits> TypeInfo;
1311 TypeInfo = getContext().getTypeInfoDataSizeInChars(Ty);
1313 TypeInfo = getContext().getTypeInfoInChars(Ty);
1315 if (alignment.isZero())
1316 alignment = TypeInfo.second;
1318 // FIXME: Handle variable sized types.
1320 // FIXME: If we have a volatile struct, the optimizer can remove what might
1321 // appear to be `extra' memory ops:
1323 // volatile struct { int i; } a, b;
1330 // we need to use a different call here. We use isVolatile to indicate when
1331 // either the source or the destination is volatile.
1333 llvm::PointerType *DPT = cast<llvm::PointerType>(DestPtr->getType());
1335 llvm::Type::getInt8PtrTy(getLLVMContext(), DPT->getAddressSpace());
1336 DestPtr = Builder.CreateBitCast(DestPtr, DBP);
1338 llvm::PointerType *SPT = cast<llvm::PointerType>(SrcPtr->getType());
1340 llvm::Type::getInt8PtrTy(getLLVMContext(), SPT->getAddressSpace());
1341 SrcPtr = Builder.CreateBitCast(SrcPtr, SBP);
1343 // Don't do any of the memmove_collectable tests if GC isn't set.
1344 if (CGM.getLangOpts().getGC() == LangOptions::NonGC) {
1346 } else if (const RecordType *RecordTy = Ty->getAs<RecordType>()) {
1347 RecordDecl *Record = RecordTy->getDecl();
1348 if (Record->hasObjectMember()) {
1349 CharUnits size = TypeInfo.first;
1350 llvm::Type *SizeTy = ConvertType(getContext().getSizeType());
1351 llvm::Value *SizeVal = llvm::ConstantInt::get(SizeTy, size.getQuantity());
1352 CGM.getObjCRuntime().EmitGCMemmoveCollectable(*this, DestPtr, SrcPtr,
1356 } else if (Ty->isArrayType()) {
1357 QualType BaseType = getContext().getBaseElementType(Ty);
1358 if (const RecordType *RecordTy = BaseType->getAs<RecordType>()) {
1359 if (RecordTy->getDecl()->hasObjectMember()) {
1360 CharUnits size = TypeInfo.first;
1361 llvm::Type *SizeTy = ConvertType(getContext().getSizeType());
1362 llvm::Value *SizeVal =
1363 llvm::ConstantInt::get(SizeTy, size.getQuantity());
1364 CGM.getObjCRuntime().EmitGCMemmoveCollectable(*this, DestPtr, SrcPtr,
1371 // Determine the metadata to describe the position of any padding in this
1372 // memcpy, as well as the TBAA tags for the members of the struct, in case
1373 // the optimizer wishes to expand it in to scalar memory operations.
1374 llvm::MDNode *TBAAStructTag = CGM.getTBAAStructInfo(Ty);
1376 Builder.CreateMemCpy(DestPtr, SrcPtr,
1377 llvm::ConstantInt::get(IntPtrTy,
1378 TypeInfo.first.getQuantity()),
1379 alignment.getQuantity(), isVolatile,
1380 /*TBAATag=*/0, TBAAStructTag);
1383 void CodeGenFunction::MaybeEmitStdInitializerListCleanup(llvm::Value *loc,
1385 const ExprWithCleanups *cleanups = dyn_cast<ExprWithCleanups>(init);
1387 init = cleanups->getSubExpr();
1389 if (isa<InitListExpr>(init) &&
1390 cast<InitListExpr>(init)->initializesStdInitializerList()) {
1391 // We initialized this std::initializer_list with an initializer list.
1392 // A backing array was created. Push a cleanup for it.
1393 EmitStdInitializerListCleanup(loc, cast<InitListExpr>(init));
1397 static void EmitRecursiveStdInitializerListCleanup(CodeGenFunction &CGF,
1398 llvm::Value *arrayStart,
1399 const InitListExpr *init) {
1400 // Check if there are any recursive cleanups to do, i.e. if we have
1401 // std::initializer_list<std::initializer_list<obj>> list = {{obj()}};
1402 // then we need to destroy the inner array as well.
1403 for (unsigned i = 0, e = init->getNumInits(); i != e; ++i) {
1404 const InitListExpr *subInit = dyn_cast<InitListExpr>(init->getInit(i));
1405 if (!subInit || !subInit->initializesStdInitializerList())
1408 // This one needs to be destroyed. Get the address of the std::init_list.
1409 llvm::Value *offset = llvm::ConstantInt::get(CGF.SizeTy, i);
1410 llvm::Value *loc = CGF.Builder.CreateInBoundsGEP(arrayStart, offset,
1412 CGF.EmitStdInitializerListCleanup(loc, subInit);
1416 void CodeGenFunction::EmitStdInitializerListCleanup(llvm::Value *loc,
1417 const InitListExpr *init) {
1418 ASTContext &ctx = getContext();
1419 QualType element = GetStdInitializerListElementType(init->getType());
1420 unsigned numInits = init->getNumInits();
1421 llvm::APInt size(ctx.getTypeSize(ctx.getSizeType()), numInits);
1422 QualType array =ctx.getConstantArrayType(element, size, ArrayType::Normal, 0);
1423 QualType arrayPtr = ctx.getPointerType(array);
1424 llvm::Type *arrayPtrType = ConvertType(arrayPtr);
1426 // lvalue is the location of a std::initializer_list, which as its first
1427 // element has a pointer to the array we want to destroy.
1428 llvm::Value *startPointer = Builder.CreateStructGEP(loc, 0, "startPointer");
1429 llvm::Value *startAddress = Builder.CreateLoad(startPointer, "startAddress");
1431 ::EmitRecursiveStdInitializerListCleanup(*this, startAddress, init);
1433 llvm::Value *arrayAddress =
1434 Builder.CreateBitCast(startAddress, arrayPtrType, "arrayAddress");
1435 ::EmitStdInitializerListCleanup(*this, array, arrayAddress, init);