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 "CGObjCRuntime.h"
16 #include "CodeGenModule.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/IR/Constants.h"
22 #include "llvm/IR/Function.h"
23 #include "llvm/IR/GlobalVariable.h"
24 #include "llvm/IR/Intrinsics.h"
25 using namespace clang;
26 using namespace CodeGen;
28 //===----------------------------------------------------------------------===//
29 // Aggregate Expression Emitter
30 //===----------------------------------------------------------------------===//
32 llvm::Value *AggValueSlot::getPaddedAtomicAddr() const {
33 assert(isValueOfAtomic());
34 llvm::GEPOperator *op = cast<llvm::GEPOperator>(getAddr());
35 assert(op->getNumIndices() == 2);
36 assert(op->hasAllZeroIndices());
37 return op->getPointerOperand();
41 class AggExprEmitter : public StmtVisitor<AggExprEmitter> {
46 /// We want to use 'dest' as the return slot except under two
48 /// - The destination slot requires garbage collection, so we
49 /// need to use the GC API.
50 /// - The destination slot is potentially aliased.
51 bool shouldUseDestForReturnSlot() const {
52 return !(Dest.requiresGCollection() || Dest.isPotentiallyAliased());
55 ReturnValueSlot getReturnValueSlot() const {
56 if (!shouldUseDestForReturnSlot())
57 return ReturnValueSlot();
59 return ReturnValueSlot(Dest.getAddr(), Dest.isVolatile());
62 AggValueSlot EnsureSlot(QualType T) {
63 if (!Dest.isIgnored()) return Dest;
64 return CGF.CreateAggTemp(T, "agg.tmp.ensured");
66 void EnsureDest(QualType T) {
67 if (!Dest.isIgnored()) return;
68 Dest = CGF.CreateAggTemp(T, "agg.tmp.ensured");
72 AggExprEmitter(CodeGenFunction &cgf, AggValueSlot Dest)
73 : CGF(cgf), Builder(CGF.Builder), Dest(Dest) {
76 //===--------------------------------------------------------------------===//
78 //===--------------------------------------------------------------------===//
80 /// EmitAggLoadOfLValue - Given an expression with aggregate type that
81 /// represents a value lvalue, this method emits the address of the lvalue,
82 /// then loads the result into DestPtr.
83 void EmitAggLoadOfLValue(const Expr *E);
85 /// EmitFinalDestCopy - Perform the final copy to DestPtr, if desired.
86 void EmitFinalDestCopy(QualType type, const LValue &src);
87 void EmitFinalDestCopy(QualType type, RValue src,
88 CharUnits srcAlignment = CharUnits::Zero());
89 void EmitCopy(QualType type, const AggValueSlot &dest,
90 const AggValueSlot &src);
92 void EmitMoveFromReturnSlot(const Expr *E, RValue Src);
94 void EmitStdInitializerList(llvm::Value *DestPtr, InitListExpr *InitList);
95 void EmitArrayInit(llvm::Value *DestPtr, llvm::ArrayType *AType,
96 QualType elementType, InitListExpr *E);
98 AggValueSlot::NeedsGCBarriers_t needsGC(QualType T) {
99 if (CGF.getLangOpts().getGC() && TypeRequiresGCollection(T))
100 return AggValueSlot::NeedsGCBarriers;
101 return AggValueSlot::DoesNotNeedGCBarriers;
104 bool TypeRequiresGCollection(QualType T);
106 //===--------------------------------------------------------------------===//
108 //===--------------------------------------------------------------------===//
110 void VisitStmt(Stmt *S) {
111 CGF.ErrorUnsupported(S, "aggregate expression");
113 void VisitParenExpr(ParenExpr *PE) { Visit(PE->getSubExpr()); }
114 void VisitGenericSelectionExpr(GenericSelectionExpr *GE) {
115 Visit(GE->getResultExpr());
117 void VisitUnaryExtension(UnaryOperator *E) { Visit(E->getSubExpr()); }
118 void VisitSubstNonTypeTemplateParmExpr(SubstNonTypeTemplateParmExpr *E) {
119 return Visit(E->getReplacement());
123 void VisitDeclRefExpr(DeclRefExpr *E) {
124 // For aggregates, we should always be able to emit the variable
125 // as an l-value unless it's a reference. This is due to the fact
126 // that we can't actually ever see a normal l2r conversion on an
127 // aggregate in C++, and in C there's no language standard
128 // actively preventing us from listing variables in the captures
130 if (E->getDecl()->getType()->isReferenceType()) {
131 if (CodeGenFunction::ConstantEmission result
132 = CGF.tryEmitAsConstant(E)) {
133 EmitFinalDestCopy(E->getType(), result.getReferenceLValue(CGF, E));
138 EmitAggLoadOfLValue(E);
141 void VisitMemberExpr(MemberExpr *ME) { EmitAggLoadOfLValue(ME); }
142 void VisitUnaryDeref(UnaryOperator *E) { EmitAggLoadOfLValue(E); }
143 void VisitStringLiteral(StringLiteral *E) { EmitAggLoadOfLValue(E); }
144 void VisitCompoundLiteralExpr(CompoundLiteralExpr *E);
145 void VisitArraySubscriptExpr(ArraySubscriptExpr *E) {
146 EmitAggLoadOfLValue(E);
148 void VisitPredefinedExpr(const PredefinedExpr *E) {
149 EmitAggLoadOfLValue(E);
153 void VisitCastExpr(CastExpr *E);
154 void VisitCallExpr(const CallExpr *E);
155 void VisitStmtExpr(const StmtExpr *E);
156 void VisitBinaryOperator(const BinaryOperator *BO);
157 void VisitPointerToDataMemberBinaryOperator(const BinaryOperator *BO);
158 void VisitBinAssign(const BinaryOperator *E);
159 void VisitBinComma(const BinaryOperator *E);
161 void VisitObjCMessageExpr(ObjCMessageExpr *E);
162 void VisitObjCIvarRefExpr(ObjCIvarRefExpr *E) {
163 EmitAggLoadOfLValue(E);
166 void VisitAbstractConditionalOperator(const AbstractConditionalOperator *CO);
167 void VisitChooseExpr(const ChooseExpr *CE);
168 void VisitInitListExpr(InitListExpr *E);
169 void VisitImplicitValueInitExpr(ImplicitValueInitExpr *E);
170 void VisitCXXDefaultArgExpr(CXXDefaultArgExpr *DAE) {
171 Visit(DAE->getExpr());
173 void VisitCXXDefaultInitExpr(CXXDefaultInitExpr *DIE) {
174 CodeGenFunction::CXXDefaultInitExprScope Scope(CGF);
175 Visit(DIE->getExpr());
177 void VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E);
178 void VisitCXXConstructExpr(const CXXConstructExpr *E);
179 void VisitLambdaExpr(LambdaExpr *E);
180 void VisitExprWithCleanups(ExprWithCleanups *E);
181 void VisitCXXScalarValueInitExpr(CXXScalarValueInitExpr *E);
182 void VisitCXXTypeidExpr(CXXTypeidExpr *E) { EmitAggLoadOfLValue(E); }
183 void VisitMaterializeTemporaryExpr(MaterializeTemporaryExpr *E);
184 void VisitOpaqueValueExpr(OpaqueValueExpr *E);
186 void VisitPseudoObjectExpr(PseudoObjectExpr *E) {
187 if (E->isGLValue()) {
188 LValue LV = CGF.EmitPseudoObjectLValue(E);
189 return EmitFinalDestCopy(E->getType(), LV);
192 CGF.EmitPseudoObjectRValue(E, EnsureSlot(E->getType()));
195 void VisitVAArgExpr(VAArgExpr *E);
197 void EmitInitializationToLValue(Expr *E, LValue Address);
198 void EmitNullInitializationToLValue(LValue Address);
199 // case Expr::ChooseExprClass:
200 void VisitCXXThrowExpr(const CXXThrowExpr *E) { CGF.EmitCXXThrowExpr(E); }
201 void VisitAtomicExpr(AtomicExpr *E) {
202 CGF.EmitAtomicExpr(E, EnsureSlot(E->getType()).getAddr());
206 /// A helper class for emitting expressions into the value sub-object
207 /// of a padded atomic type.
208 class ValueDestForAtomic {
211 ValueDestForAtomic(CodeGenFunction &CGF, AggValueSlot dest, QualType type)
213 assert(!Dest.isValueOfAtomic());
214 if (!Dest.isIgnored() && CGF.CGM.isPaddedAtomicType(type)) {
215 llvm::Value *valueAddr = CGF.Builder.CreateStructGEP(Dest.getAddr(), 0);
216 Dest = AggValueSlot::forAddr(valueAddr,
218 Dest.getQualifiers(),
219 Dest.isExternallyDestructed(),
220 Dest.requiresGCollection(),
221 Dest.isPotentiallyAliased(),
223 AggValueSlot::IsValueOfAtomic);
227 const AggValueSlot &getDest() const { return Dest; }
229 ~ValueDestForAtomic() {
230 // Kill the GEP if we made one and it didn't end up used.
231 if (Dest.isValueOfAtomic()) {
232 llvm::Instruction *addr = cast<llvm::GetElementPtrInst>(Dest.getAddr());
233 if (addr->use_empty()) addr->eraseFromParent();
237 } // end anonymous namespace.
239 //===----------------------------------------------------------------------===//
241 //===----------------------------------------------------------------------===//
243 /// EmitAggLoadOfLValue - Given an expression with aggregate type that
244 /// represents a value lvalue, this method emits the address of the lvalue,
245 /// then loads the result into DestPtr.
246 void AggExprEmitter::EmitAggLoadOfLValue(const Expr *E) {
247 LValue LV = CGF.EmitLValue(E);
249 // If the type of the l-value is atomic, then do an atomic load.
250 if (LV.getType()->isAtomicType()) {
251 ValueDestForAtomic valueDest(CGF, Dest, LV.getType());
252 CGF.EmitAtomicLoad(LV, valueDest.getDest());
256 EmitFinalDestCopy(E->getType(), LV);
259 /// \brief True if the given aggregate type requires special GC API calls.
260 bool AggExprEmitter::TypeRequiresGCollection(QualType T) {
261 // Only record types have members that might require garbage collection.
262 const RecordType *RecordTy = T->getAs<RecordType>();
263 if (!RecordTy) return false;
265 // Don't mess with non-trivial C++ types.
266 RecordDecl *Record = RecordTy->getDecl();
267 if (isa<CXXRecordDecl>(Record) &&
268 (cast<CXXRecordDecl>(Record)->hasNonTrivialCopyConstructor() ||
269 !cast<CXXRecordDecl>(Record)->hasTrivialDestructor()))
272 // Check whether the type has an object member.
273 return Record->hasObjectMember();
276 /// \brief Perform the final move to DestPtr if for some reason
277 /// getReturnValueSlot() didn't use it directly.
279 /// The idea is that you do something like this:
280 /// RValue Result = EmitSomething(..., getReturnValueSlot());
281 /// EmitMoveFromReturnSlot(E, Result);
283 /// If nothing interferes, this will cause the result to be emitted
284 /// directly into the return value slot. Otherwise, a final move
285 /// will be performed.
286 void AggExprEmitter::EmitMoveFromReturnSlot(const Expr *E, RValue src) {
287 if (shouldUseDestForReturnSlot()) {
288 // Logically, Dest.getAddr() should equal Src.getAggregateAddr().
289 // The possibility of undef rvalues complicates that a lot,
290 // though, so we can't really assert.
294 // Otherwise, copy from there to the destination.
295 assert(Dest.getAddr() != src.getAggregateAddr());
296 std::pair<CharUnits, CharUnits> typeInfo =
297 CGF.getContext().getTypeInfoInChars(E->getType());
298 EmitFinalDestCopy(E->getType(), src, typeInfo.second);
301 /// EmitFinalDestCopy - Perform the final copy to DestPtr, if desired.
302 void AggExprEmitter::EmitFinalDestCopy(QualType type, RValue src,
303 CharUnits srcAlign) {
304 assert(src.isAggregate() && "value must be aggregate value!");
305 LValue srcLV = CGF.MakeAddrLValue(src.getAggregateAddr(), type, srcAlign);
306 EmitFinalDestCopy(type, srcLV);
309 /// EmitFinalDestCopy - Perform the final copy to DestPtr, if desired.
310 void AggExprEmitter::EmitFinalDestCopy(QualType type, const LValue &src) {
311 // If Dest is ignored, then we're evaluating an aggregate expression
312 // in a context that doesn't care about the result. Note that loads
313 // from volatile l-values force the existence of a non-ignored
315 if (Dest.isIgnored())
318 AggValueSlot srcAgg =
319 AggValueSlot::forLValue(src, AggValueSlot::IsDestructed,
320 needsGC(type), AggValueSlot::IsAliased);
321 EmitCopy(type, Dest, srcAgg);
324 /// Perform a copy from the source into the destination.
326 /// \param type - the type of the aggregate being copied; qualifiers are
328 void AggExprEmitter::EmitCopy(QualType type, const AggValueSlot &dest,
329 const AggValueSlot &src) {
330 if (dest.requiresGCollection()) {
331 CharUnits sz = CGF.getContext().getTypeSizeInChars(type);
332 llvm::Value *size = llvm::ConstantInt::get(CGF.SizeTy, sz.getQuantity());
333 CGF.CGM.getObjCRuntime().EmitGCMemmoveCollectable(CGF,
340 // If the result of the assignment is used, copy the LHS there also.
341 // It's volatile if either side is. Use the minimum alignment of
343 CGF.EmitAggregateCopy(dest.getAddr(), src.getAddr(), type,
344 dest.isVolatile() || src.isVolatile(),
345 std::min(dest.getAlignment(), src.getAlignment()));
348 static QualType GetStdInitializerListElementType(QualType T) {
349 // Just assume that this is really std::initializer_list.
350 ClassTemplateSpecializationDecl *specialization =
351 cast<ClassTemplateSpecializationDecl>(T->castAs<RecordType>()->getDecl());
352 return specialization->getTemplateArgs()[0].getAsType();
355 /// \brief Prepare cleanup for the temporary array.
356 static void EmitStdInitializerListCleanup(CodeGenFunction &CGF,
359 const InitListExpr *initList) {
360 QualType::DestructionKind dtorKind = arrayType.isDestructedType();
362 return; // Type doesn't need destroying.
363 if (dtorKind != QualType::DK_cxx_destructor) {
364 CGF.ErrorUnsupported(initList, "ObjC ARC type in initializer_list");
368 CodeGenFunction::Destroyer *destroyer = CGF.getDestroyer(dtorKind);
369 CGF.pushDestroy(NormalAndEHCleanup, addr, arrayType, destroyer,
373 /// \brief Emit the initializer for a std::initializer_list initialized with a
374 /// real initializer list.
375 void AggExprEmitter::EmitStdInitializerList(llvm::Value *destPtr,
376 InitListExpr *initList) {
377 // We emit an array containing the elements, then have the init list point
379 ASTContext &ctx = CGF.getContext();
380 unsigned numInits = initList->getNumInits();
381 QualType element = GetStdInitializerListElementType(initList->getType());
382 llvm::APInt size(ctx.getTypeSize(ctx.getSizeType()), numInits);
383 QualType array = ctx.getConstantArrayType(element, size, ArrayType::Normal,0);
384 llvm::Type *LTy = CGF.ConvertTypeForMem(array);
385 llvm::AllocaInst *alloc = CGF.CreateTempAlloca(LTy);
386 alloc->setAlignment(ctx.getTypeAlignInChars(array).getQuantity());
387 alloc->setName(".initlist.");
389 EmitArrayInit(alloc, cast<llvm::ArrayType>(LTy), element, initList);
391 // FIXME: The diagnostics are somewhat out of place here.
392 RecordDecl *record = initList->getType()->castAs<RecordType>()->getDecl();
393 RecordDecl::field_iterator field = record->field_begin();
394 if (field == record->field_end()) {
395 CGF.ErrorUnsupported(initList, "weird std::initializer_list");
399 QualType elementPtr = ctx.getPointerType(element.withConst());
402 if (!ctx.hasSameType(field->getType(), elementPtr)) {
403 CGF.ErrorUnsupported(initList, "weird std::initializer_list");
406 LValue DestLV = CGF.MakeNaturalAlignAddrLValue(destPtr, initList->getType());
407 LValue start = CGF.EmitLValueForFieldInitialization(DestLV, *field);
408 llvm::Value *arrayStart = Builder.CreateStructGEP(alloc, 0, "arraystart");
409 CGF.EmitStoreThroughLValue(RValue::get(arrayStart), start);
412 if (field == record->field_end()) {
413 CGF.ErrorUnsupported(initList, "weird std::initializer_list");
416 LValue endOrLength = CGF.EmitLValueForFieldInitialization(DestLV, *field);
417 if (ctx.hasSameType(field->getType(), elementPtr)) {
419 llvm::Value *arrayEnd = Builder.CreateStructGEP(alloc,numInits, "arrayend");
420 CGF.EmitStoreThroughLValue(RValue::get(arrayEnd), endOrLength);
421 } else if(ctx.hasSameType(field->getType(), ctx.getSizeType())) {
423 CGF.EmitStoreThroughLValue(RValue::get(Builder.getInt(size)), endOrLength);
425 CGF.ErrorUnsupported(initList, "weird std::initializer_list");
429 if (!Dest.isExternallyDestructed())
430 EmitStdInitializerListCleanup(CGF, array, alloc, initList);
433 /// \brief Emit initialization of an array from an initializer list.
434 void AggExprEmitter::EmitArrayInit(llvm::Value *DestPtr, llvm::ArrayType *AType,
435 QualType elementType, InitListExpr *E) {
436 uint64_t NumInitElements = E->getNumInits();
438 uint64_t NumArrayElements = AType->getNumElements();
439 assert(NumInitElements <= NumArrayElements);
441 // DestPtr is an array*. Construct an elementType* by drilling
443 llvm::Value *zero = llvm::ConstantInt::get(CGF.SizeTy, 0);
444 llvm::Value *indices[] = { zero, zero };
446 Builder.CreateInBoundsGEP(DestPtr, indices, "arrayinit.begin");
448 // Exception safety requires us to destroy all the
449 // already-constructed members if an initializer throws.
450 // For that, we'll need an EH cleanup.
451 QualType::DestructionKind dtorKind = elementType.isDestructedType();
452 llvm::AllocaInst *endOfInit = 0;
453 EHScopeStack::stable_iterator cleanup;
454 llvm::Instruction *cleanupDominator = 0;
455 if (CGF.needsEHCleanup(dtorKind)) {
456 // In principle we could tell the cleanup where we are more
457 // directly, but the control flow can get so varied here that it
458 // would actually be quite complex. Therefore we go through an
460 endOfInit = CGF.CreateTempAlloca(begin->getType(),
461 "arrayinit.endOfInit");
462 cleanupDominator = Builder.CreateStore(begin, endOfInit);
463 CGF.pushIrregularPartialArrayCleanup(begin, endOfInit, elementType,
464 CGF.getDestroyer(dtorKind));
465 cleanup = CGF.EHStack.stable_begin();
467 // Otherwise, remember that we didn't need a cleanup.
469 dtorKind = QualType::DK_none;
472 llvm::Value *one = llvm::ConstantInt::get(CGF.SizeTy, 1);
474 // The 'current element to initialize'. The invariants on this
475 // variable are complicated. Essentially, after each iteration of
476 // the loop, it points to the last initialized element, except
477 // that it points to the beginning of the array before any
478 // elements have been initialized.
479 llvm::Value *element = begin;
481 // Emit the explicit initializers.
482 for (uint64_t i = 0; i != NumInitElements; ++i) {
483 // Advance to the next element.
485 element = Builder.CreateInBoundsGEP(element, one, "arrayinit.element");
487 // Tell the cleanup that it needs to destroy up to this
488 // element. TODO: some of these stores can be trivially
489 // observed to be unnecessary.
490 if (endOfInit) Builder.CreateStore(element, endOfInit);
493 // If these are nested std::initializer_list inits, do them directly,
494 // because they are conceptually the same "location".
495 InitListExpr *initList = dyn_cast<InitListExpr>(E->getInit(i));
496 if (initList && initList->initializesStdInitializerList()) {
497 EmitStdInitializerList(element, initList);
499 LValue elementLV = CGF.MakeAddrLValue(element, elementType);
500 EmitInitializationToLValue(E->getInit(i), elementLV);
504 // Check whether there's a non-trivial array-fill expression.
505 // Note that this will be a CXXConstructExpr even if the element
506 // type is an array (or array of array, etc.) of class type.
507 Expr *filler = E->getArrayFiller();
508 bool hasTrivialFiller = true;
509 if (CXXConstructExpr *cons = dyn_cast_or_null<CXXConstructExpr>(filler)) {
510 assert(cons->getConstructor()->isDefaultConstructor());
511 hasTrivialFiller = cons->getConstructor()->isTrivial();
514 // Any remaining elements need to be zero-initialized, possibly
515 // using the filler expression. We can skip this if the we're
516 // emitting to zeroed memory.
517 if (NumInitElements != NumArrayElements &&
518 !(Dest.isZeroed() && hasTrivialFiller &&
519 CGF.getTypes().isZeroInitializable(elementType))) {
521 // Use an actual loop. This is basically
522 // do { *array++ = filler; } while (array != end);
524 // Advance to the start of the rest of the array.
525 if (NumInitElements) {
526 element = Builder.CreateInBoundsGEP(element, one, "arrayinit.start");
527 if (endOfInit) Builder.CreateStore(element, endOfInit);
530 // Compute the end of the array.
531 llvm::Value *end = Builder.CreateInBoundsGEP(begin,
532 llvm::ConstantInt::get(CGF.SizeTy, NumArrayElements),
535 llvm::BasicBlock *entryBB = Builder.GetInsertBlock();
536 llvm::BasicBlock *bodyBB = CGF.createBasicBlock("arrayinit.body");
538 // Jump into the body.
539 CGF.EmitBlock(bodyBB);
540 llvm::PHINode *currentElement =
541 Builder.CreatePHI(element->getType(), 2, "arrayinit.cur");
542 currentElement->addIncoming(element, entryBB);
544 // Emit the actual filler expression.
545 LValue elementLV = CGF.MakeAddrLValue(currentElement, elementType);
547 EmitInitializationToLValue(filler, elementLV);
549 EmitNullInitializationToLValue(elementLV);
551 // Move on to the next element.
552 llvm::Value *nextElement =
553 Builder.CreateInBoundsGEP(currentElement, one, "arrayinit.next");
555 // Tell the EH cleanup that we finished with the last element.
556 if (endOfInit) Builder.CreateStore(nextElement, endOfInit);
558 // Leave the loop if we're done.
559 llvm::Value *done = Builder.CreateICmpEQ(nextElement, end,
561 llvm::BasicBlock *endBB = CGF.createBasicBlock("arrayinit.end");
562 Builder.CreateCondBr(done, endBB, bodyBB);
563 currentElement->addIncoming(nextElement, Builder.GetInsertBlock());
565 CGF.EmitBlock(endBB);
568 // Leave the partial-array cleanup if we entered one.
569 if (dtorKind) CGF.DeactivateCleanupBlock(cleanup, cleanupDominator);
572 //===----------------------------------------------------------------------===//
574 //===----------------------------------------------------------------------===//
576 void AggExprEmitter::VisitMaterializeTemporaryExpr(MaterializeTemporaryExpr *E){
577 Visit(E->GetTemporaryExpr());
580 void AggExprEmitter::VisitOpaqueValueExpr(OpaqueValueExpr *e) {
581 EmitFinalDestCopy(e->getType(), CGF.getOpaqueLValueMapping(e));
585 AggExprEmitter::VisitCompoundLiteralExpr(CompoundLiteralExpr *E) {
586 if (Dest.isPotentiallyAliased() &&
587 E->getType().isPODType(CGF.getContext())) {
588 // For a POD type, just emit a load of the lvalue + a copy, because our
589 // compound literal might alias the destination.
590 EmitAggLoadOfLValue(E);
594 AggValueSlot Slot = EnsureSlot(E->getType());
595 CGF.EmitAggExpr(E->getInitializer(), Slot);
598 /// Attempt to look through various unimportant expressions to find a
599 /// cast of the given kind.
600 static Expr *findPeephole(Expr *op, CastKind kind) {
602 op = op->IgnoreParens();
603 if (CastExpr *castE = dyn_cast<CastExpr>(op)) {
604 if (castE->getCastKind() == kind)
605 return castE->getSubExpr();
606 if (castE->getCastKind() == CK_NoOp)
613 void AggExprEmitter::VisitCastExpr(CastExpr *E) {
614 switch (E->getCastKind()) {
616 // FIXME: Can this actually happen? We have no test coverage for it.
617 assert(isa<CXXDynamicCastExpr>(E) && "CK_Dynamic without a dynamic_cast?");
618 LValue LV = CGF.EmitCheckedLValue(E->getSubExpr(),
619 CodeGenFunction::TCK_Load);
620 // FIXME: Do we also need to handle property references here?
622 CGF.EmitDynamicCast(LV.getAddress(), cast<CXXDynamicCastExpr>(E));
624 CGF.CGM.ErrorUnsupported(E, "non-simple lvalue dynamic_cast");
626 if (!Dest.isIgnored())
627 CGF.CGM.ErrorUnsupported(E, "lvalue dynamic_cast with a destination");
632 if (Dest.isIgnored()) break;
634 // GCC union extension
635 QualType Ty = E->getSubExpr()->getType();
636 QualType PtrTy = CGF.getContext().getPointerType(Ty);
637 llvm::Value *CastPtr = Builder.CreateBitCast(Dest.getAddr(),
638 CGF.ConvertType(PtrTy));
639 EmitInitializationToLValue(E->getSubExpr(),
640 CGF.MakeAddrLValue(CastPtr, Ty));
644 case CK_DerivedToBase:
645 case CK_BaseToDerived:
646 case CK_UncheckedDerivedToBase: {
647 llvm_unreachable("cannot perform hierarchy conversion in EmitAggExpr: "
648 "should have been unpacked before we got here");
651 case CK_NonAtomicToAtomic:
652 case CK_AtomicToNonAtomic: {
653 bool isToAtomic = (E->getCastKind() == CK_NonAtomicToAtomic);
655 // Determine the atomic and value types.
656 QualType atomicType = E->getSubExpr()->getType();
657 QualType valueType = E->getType();
658 if (isToAtomic) std::swap(atomicType, valueType);
660 assert(atomicType->isAtomicType());
661 assert(CGF.getContext().hasSameUnqualifiedType(valueType,
662 atomicType->castAs<AtomicType>()->getValueType()));
664 // Just recurse normally if we're ignoring the result or the
665 // atomic type doesn't change representation.
666 if (Dest.isIgnored() || !CGF.CGM.isPaddedAtomicType(atomicType)) {
667 return Visit(E->getSubExpr());
670 CastKind peepholeTarget =
671 (isToAtomic ? CK_AtomicToNonAtomic : CK_NonAtomicToAtomic);
673 // These two cases are reverses of each other; try to peephole them.
674 if (Expr *op = findPeephole(E->getSubExpr(), peepholeTarget)) {
675 assert(CGF.getContext().hasSameUnqualifiedType(op->getType(),
677 "peephole significantly changed types?");
681 // If we're converting an r-value of non-atomic type to an r-value
682 // of atomic type, just make an atomic temporary, emit into that,
683 // and then copy the value out. (FIXME: do we need to
684 // zero-initialize it first?)
686 ValueDestForAtomic valueDest(CGF, Dest, atomicType);
687 CGF.EmitAggExpr(E->getSubExpr(), valueDest.getDest());
691 // Otherwise, we're converting an atomic type to a non-atomic type.
693 // If the dest is a value-of-atomic subobject, drill back out.
694 if (Dest.isValueOfAtomic()) {
695 AggValueSlot atomicSlot =
696 AggValueSlot::forAddr(Dest.getPaddedAtomicAddr(),
698 Dest.getQualifiers(),
699 Dest.isExternallyDestructed(),
700 Dest.requiresGCollection(),
701 Dest.isPotentiallyAliased(),
703 AggValueSlot::IsNotValueOfAtomic);
704 CGF.EmitAggExpr(E->getSubExpr(), atomicSlot);
708 // Otherwise, make an atomic temporary, emit into that, and then
709 // copy the value out.
710 AggValueSlot atomicSlot =
711 CGF.CreateAggTemp(atomicType, "atomic-to-nonatomic.temp");
712 CGF.EmitAggExpr(E->getSubExpr(), atomicSlot);
714 llvm::Value *valueAddr =
715 Builder.CreateStructGEP(atomicSlot.getAddr(), 0);
716 RValue rvalue = RValue::getAggregate(valueAddr, atomicSlot.isVolatile());
717 return EmitFinalDestCopy(valueType, rvalue);
720 case CK_LValueToRValue:
721 // If we're loading from a volatile type, force the destination
723 if (E->getSubExpr()->getType().isVolatileQualified()) {
724 EnsureDest(E->getType());
725 return Visit(E->getSubExpr());
731 case CK_UserDefinedConversion:
732 case CK_ConstructorConversion:
733 assert(CGF.getContext().hasSameUnqualifiedType(E->getSubExpr()->getType(),
735 "Implicit cast types must be compatible");
736 Visit(E->getSubExpr());
739 case CK_LValueBitCast:
740 llvm_unreachable("should not be emitting lvalue bitcast as rvalue");
744 case CK_ArrayToPointerDecay:
745 case CK_FunctionToPointerDecay:
746 case CK_NullToPointer:
747 case CK_NullToMemberPointer:
748 case CK_BaseToDerivedMemberPointer:
749 case CK_DerivedToBaseMemberPointer:
750 case CK_MemberPointerToBoolean:
751 case CK_ReinterpretMemberPointer:
752 case CK_IntegralToPointer:
753 case CK_PointerToIntegral:
754 case CK_PointerToBoolean:
757 case CK_IntegralCast:
758 case CK_IntegralToBoolean:
759 case CK_IntegralToFloating:
760 case CK_FloatingToIntegral:
761 case CK_FloatingToBoolean:
762 case CK_FloatingCast:
763 case CK_CPointerToObjCPointerCast:
764 case CK_BlockPointerToObjCPointerCast:
765 case CK_AnyPointerToBlockPointerCast:
766 case CK_ObjCObjectLValueCast:
767 case CK_FloatingRealToComplex:
768 case CK_FloatingComplexToReal:
769 case CK_FloatingComplexToBoolean:
770 case CK_FloatingComplexCast:
771 case CK_FloatingComplexToIntegralComplex:
772 case CK_IntegralRealToComplex:
773 case CK_IntegralComplexToReal:
774 case CK_IntegralComplexToBoolean:
775 case CK_IntegralComplexCast:
776 case CK_IntegralComplexToFloatingComplex:
777 case CK_ARCProduceObject:
778 case CK_ARCConsumeObject:
779 case CK_ARCReclaimReturnedObject:
780 case CK_ARCExtendBlockObject:
781 case CK_CopyAndAutoreleaseBlockObject:
782 case CK_BuiltinFnToFnPtr:
783 case CK_ZeroToOCLEvent:
784 llvm_unreachable("cast kind invalid for aggregate types");
788 void AggExprEmitter::VisitCallExpr(const CallExpr *E) {
789 if (E->getCallReturnType()->isReferenceType()) {
790 EmitAggLoadOfLValue(E);
794 RValue RV = CGF.EmitCallExpr(E, getReturnValueSlot());
795 EmitMoveFromReturnSlot(E, RV);
798 void AggExprEmitter::VisitObjCMessageExpr(ObjCMessageExpr *E) {
799 RValue RV = CGF.EmitObjCMessageExpr(E, getReturnValueSlot());
800 EmitMoveFromReturnSlot(E, RV);
803 void AggExprEmitter::VisitBinComma(const BinaryOperator *E) {
804 CGF.EmitIgnoredExpr(E->getLHS());
808 void AggExprEmitter::VisitStmtExpr(const StmtExpr *E) {
809 CodeGenFunction::StmtExprEvaluation eval(CGF);
810 CGF.EmitCompoundStmt(*E->getSubStmt(), true, Dest);
813 void AggExprEmitter::VisitBinaryOperator(const BinaryOperator *E) {
814 if (E->getOpcode() == BO_PtrMemD || E->getOpcode() == BO_PtrMemI)
815 VisitPointerToDataMemberBinaryOperator(E);
817 CGF.ErrorUnsupported(E, "aggregate binary expression");
820 void AggExprEmitter::VisitPointerToDataMemberBinaryOperator(
821 const BinaryOperator *E) {
822 LValue LV = CGF.EmitPointerToDataMemberBinaryExpr(E);
823 EmitFinalDestCopy(E->getType(), LV);
826 /// Is the value of the given expression possibly a reference to or
827 /// into a __block variable?
828 static bool isBlockVarRef(const Expr *E) {
829 // Make sure we look through parens.
830 E = E->IgnoreParens();
832 // Check for a direct reference to a __block variable.
833 if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E)) {
834 const VarDecl *var = dyn_cast<VarDecl>(DRE->getDecl());
835 return (var && var->hasAttr<BlocksAttr>());
838 // More complicated stuff.
841 if (const BinaryOperator *op = dyn_cast<BinaryOperator>(E)) {
842 // For an assignment or pointer-to-member operation, just care
844 if (op->isAssignmentOp() || op->isPtrMemOp())
845 return isBlockVarRef(op->getLHS());
847 // For a comma, just care about the RHS.
848 if (op->getOpcode() == BO_Comma)
849 return isBlockVarRef(op->getRHS());
851 // FIXME: pointer arithmetic?
854 // Check both sides of a conditional operator.
855 } else if (const AbstractConditionalOperator *op
856 = dyn_cast<AbstractConditionalOperator>(E)) {
857 return isBlockVarRef(op->getTrueExpr())
858 || isBlockVarRef(op->getFalseExpr());
860 // OVEs are required to support BinaryConditionalOperators.
861 } else if (const OpaqueValueExpr *op
862 = dyn_cast<OpaqueValueExpr>(E)) {
863 if (const Expr *src = op->getSourceExpr())
864 return isBlockVarRef(src);
866 // Casts are necessary to get things like (*(int*)&var) = foo().
867 // We don't really care about the kind of cast here, except
868 // we don't want to look through l2r casts, because it's okay
869 // to get the *value* in a __block variable.
870 } else if (const CastExpr *cast = dyn_cast<CastExpr>(E)) {
871 if (cast->getCastKind() == CK_LValueToRValue)
873 return isBlockVarRef(cast->getSubExpr());
875 // Handle unary operators. Again, just aggressively look through
876 // it, ignoring the operation.
877 } else if (const UnaryOperator *uop = dyn_cast<UnaryOperator>(E)) {
878 return isBlockVarRef(uop->getSubExpr());
880 // Look into the base of a field access.
881 } else if (const MemberExpr *mem = dyn_cast<MemberExpr>(E)) {
882 return isBlockVarRef(mem->getBase());
884 // Look into the base of a subscript.
885 } else if (const ArraySubscriptExpr *sub = dyn_cast<ArraySubscriptExpr>(E)) {
886 return isBlockVarRef(sub->getBase());
892 void AggExprEmitter::VisitBinAssign(const BinaryOperator *E) {
893 // For an assignment to work, the value on the right has
894 // to be compatible with the value on the left.
895 assert(CGF.getContext().hasSameUnqualifiedType(E->getLHS()->getType(),
896 E->getRHS()->getType())
897 && "Invalid assignment");
899 // If the LHS might be a __block variable, and the RHS can
900 // potentially cause a block copy, we need to evaluate the RHS first
901 // so that the assignment goes the right place.
902 // This is pretty semantically fragile.
903 if (isBlockVarRef(E->getLHS()) &&
904 E->getRHS()->HasSideEffects(CGF.getContext())) {
905 // Ensure that we have a destination, and evaluate the RHS into that.
906 EnsureDest(E->getRHS()->getType());
909 // Now emit the LHS and copy into it.
910 LValue LHS = CGF.EmitCheckedLValue(E->getLHS(), CodeGenFunction::TCK_Store);
912 // That copy is an atomic copy if the LHS is atomic.
913 if (LHS.getType()->isAtomicType()) {
914 CGF.EmitAtomicStore(Dest.asRValue(), LHS, /*isInit*/ false);
918 EmitCopy(E->getLHS()->getType(),
919 AggValueSlot::forLValue(LHS, AggValueSlot::IsDestructed,
920 needsGC(E->getLHS()->getType()),
921 AggValueSlot::IsAliased),
926 LValue LHS = CGF.EmitLValue(E->getLHS());
928 // If we have an atomic type, evaluate into the destination and then
929 // do an atomic copy.
930 if (LHS.getType()->isAtomicType()) {
931 EnsureDest(E->getRHS()->getType());
933 CGF.EmitAtomicStore(Dest.asRValue(), LHS, /*isInit*/ false);
937 // Codegen the RHS so that it stores directly into the LHS.
938 AggValueSlot LHSSlot =
939 AggValueSlot::forLValue(LHS, AggValueSlot::IsDestructed,
940 needsGC(E->getLHS()->getType()),
941 AggValueSlot::IsAliased);
942 // A non-volatile aggregate destination might have volatile member.
943 if (!LHSSlot.isVolatile() &&
944 CGF.hasVolatileMember(E->getLHS()->getType()))
945 LHSSlot.setVolatile(true);
947 CGF.EmitAggExpr(E->getRHS(), LHSSlot);
949 // Copy into the destination if the assignment isn't ignored.
950 EmitFinalDestCopy(E->getType(), LHS);
953 void AggExprEmitter::
954 VisitAbstractConditionalOperator(const AbstractConditionalOperator *E) {
955 llvm::BasicBlock *LHSBlock = CGF.createBasicBlock("cond.true");
956 llvm::BasicBlock *RHSBlock = CGF.createBasicBlock("cond.false");
957 llvm::BasicBlock *ContBlock = CGF.createBasicBlock("cond.end");
959 // Bind the common expression if necessary.
960 CodeGenFunction::OpaqueValueMapping binding(CGF, E);
962 CodeGenFunction::ConditionalEvaluation eval(CGF);
963 CGF.EmitBranchOnBoolExpr(E->getCond(), LHSBlock, RHSBlock);
965 // Save whether the destination's lifetime is externally managed.
966 bool isExternallyDestructed = Dest.isExternallyDestructed();
969 CGF.EmitBlock(LHSBlock);
970 Visit(E->getTrueExpr());
973 assert(CGF.HaveInsertPoint() && "expression evaluation ended with no IP!");
974 CGF.Builder.CreateBr(ContBlock);
976 // If the result of an agg expression is unused, then the emission
977 // of the LHS might need to create a destination slot. That's fine
978 // with us, and we can safely emit the RHS into the same slot, but
979 // we shouldn't claim that it's already being destructed.
980 Dest.setExternallyDestructed(isExternallyDestructed);
983 CGF.EmitBlock(RHSBlock);
984 Visit(E->getFalseExpr());
987 CGF.EmitBlock(ContBlock);
990 void AggExprEmitter::VisitChooseExpr(const ChooseExpr *CE) {
991 Visit(CE->getChosenSubExpr(CGF.getContext()));
994 void AggExprEmitter::VisitVAArgExpr(VAArgExpr *VE) {
995 llvm::Value *ArgValue = CGF.EmitVAListRef(VE->getSubExpr());
996 llvm::Value *ArgPtr = CGF.EmitVAArg(ArgValue, VE->getType());
999 CGF.ErrorUnsupported(VE, "aggregate va_arg expression");
1003 EmitFinalDestCopy(VE->getType(), CGF.MakeAddrLValue(ArgPtr, VE->getType()));
1006 void AggExprEmitter::VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E) {
1007 // Ensure that we have a slot, but if we already do, remember
1008 // whether it was externally destructed.
1009 bool wasExternallyDestructed = Dest.isExternallyDestructed();
1010 EnsureDest(E->getType());
1012 // We're going to push a destructor if there isn't already one.
1013 Dest.setExternallyDestructed();
1015 Visit(E->getSubExpr());
1017 // Push that destructor we promised.
1018 if (!wasExternallyDestructed)
1019 CGF.EmitCXXTemporary(E->getTemporary(), E->getType(), Dest.getAddr());
1023 AggExprEmitter::VisitCXXConstructExpr(const CXXConstructExpr *E) {
1024 AggValueSlot Slot = EnsureSlot(E->getType());
1025 CGF.EmitCXXConstructExpr(E, Slot);
1029 AggExprEmitter::VisitLambdaExpr(LambdaExpr *E) {
1030 AggValueSlot Slot = EnsureSlot(E->getType());
1031 CGF.EmitLambdaExpr(E, Slot);
1034 void AggExprEmitter::VisitExprWithCleanups(ExprWithCleanups *E) {
1035 CGF.enterFullExpression(E);
1036 CodeGenFunction::RunCleanupsScope cleanups(CGF);
1037 Visit(E->getSubExpr());
1040 void AggExprEmitter::VisitCXXScalarValueInitExpr(CXXScalarValueInitExpr *E) {
1041 QualType T = E->getType();
1042 AggValueSlot Slot = EnsureSlot(T);
1043 EmitNullInitializationToLValue(CGF.MakeAddrLValue(Slot.getAddr(), T));
1046 void AggExprEmitter::VisitImplicitValueInitExpr(ImplicitValueInitExpr *E) {
1047 QualType T = E->getType();
1048 AggValueSlot Slot = EnsureSlot(T);
1049 EmitNullInitializationToLValue(CGF.MakeAddrLValue(Slot.getAddr(), T));
1052 /// isSimpleZero - If emitting this value will obviously just cause a store of
1053 /// zero to memory, return true. This can return false if uncertain, so it just
1054 /// handles simple cases.
1055 static bool isSimpleZero(const Expr *E, CodeGenFunction &CGF) {
1056 E = E->IgnoreParens();
1059 if (const IntegerLiteral *IL = dyn_cast<IntegerLiteral>(E))
1060 return IL->getValue() == 0;
1062 if (const FloatingLiteral *FL = dyn_cast<FloatingLiteral>(E))
1063 return FL->getValue().isPosZero();
1065 if ((isa<ImplicitValueInitExpr>(E) || isa<CXXScalarValueInitExpr>(E)) &&
1066 CGF.getTypes().isZeroInitializable(E->getType()))
1068 // (int*)0 - Null pointer expressions.
1069 if (const CastExpr *ICE = dyn_cast<CastExpr>(E))
1070 return ICE->getCastKind() == CK_NullToPointer;
1072 if (const CharacterLiteral *CL = dyn_cast<CharacterLiteral>(E))
1073 return CL->getValue() == 0;
1075 // Otherwise, hard case: conservatively return false.
1081 AggExprEmitter::EmitInitializationToLValue(Expr* E, LValue LV) {
1082 QualType type = LV.getType();
1083 // FIXME: Ignore result?
1084 // FIXME: Are initializers affected by volatile?
1085 if (Dest.isZeroed() && isSimpleZero(E, CGF)) {
1086 // Storing "i32 0" to a zero'd memory location is a noop.
1088 } else if (isa<ImplicitValueInitExpr>(E) || isa<CXXScalarValueInitExpr>(E)) {
1089 return EmitNullInitializationToLValue(LV);
1090 } else if (type->isReferenceType()) {
1091 RValue RV = CGF.EmitReferenceBindingToExpr(E, /*InitializedDecl=*/0);
1092 return CGF.EmitStoreThroughLValue(RV, LV);
1095 switch (CGF.getEvaluationKind(type)) {
1097 CGF.EmitComplexExprIntoLValue(E, LV, /*isInit*/ true);
1100 CGF.EmitAggExpr(E, AggValueSlot::forLValue(LV,
1101 AggValueSlot::IsDestructed,
1102 AggValueSlot::DoesNotNeedGCBarriers,
1103 AggValueSlot::IsNotAliased,
1107 if (LV.isSimple()) {
1108 CGF.EmitScalarInit(E, /*D=*/0, LV, /*Captured=*/false);
1110 CGF.EmitStoreThroughLValue(RValue::get(CGF.EmitScalarExpr(E)), LV);
1114 llvm_unreachable("bad evaluation kind");
1117 void AggExprEmitter::EmitNullInitializationToLValue(LValue lv) {
1118 QualType type = lv.getType();
1120 // If the destination slot is already zeroed out before the aggregate is
1121 // copied into it, we don't have to emit any zeros here.
1122 if (Dest.isZeroed() && CGF.getTypes().isZeroInitializable(type))
1125 if (CGF.hasScalarEvaluationKind(type)) {
1126 // For non-aggregates, we can store the appropriate null constant.
1127 llvm::Value *null = CGF.CGM.EmitNullConstant(type);
1128 // Note that the following is not equivalent to
1129 // EmitStoreThroughBitfieldLValue for ARC types.
1130 if (lv.isBitField()) {
1131 CGF.EmitStoreThroughBitfieldLValue(RValue::get(null), lv);
1133 assert(lv.isSimple());
1134 CGF.EmitStoreOfScalar(null, lv, /* isInitialization */ true);
1137 // There's a potential optimization opportunity in combining
1138 // memsets; that would be easy for arrays, but relatively
1139 // difficult for structures with the current code.
1140 CGF.EmitNullInitialization(lv.getAddress(), lv.getType());
1144 void AggExprEmitter::VisitInitListExpr(InitListExpr *E) {
1146 // FIXME: Assess perf here? Figure out what cases are worth optimizing here
1147 // (Length of globals? Chunks of zeroed-out space?).
1149 // If we can, prefer a copy from a global; this is a lot less code for long
1150 // globals, and it's easier for the current optimizers to analyze.
1151 if (llvm::Constant* C = CGF.CGM.EmitConstantExpr(E, E->getType(), &CGF)) {
1152 llvm::GlobalVariable* GV =
1153 new llvm::GlobalVariable(CGF.CGM.getModule(), C->getType(), true,
1154 llvm::GlobalValue::InternalLinkage, C, "");
1155 EmitFinalDestCopy(E->getType(), CGF.MakeAddrLValue(GV, E->getType()));
1159 if (E->hadArrayRangeDesignator())
1160 CGF.ErrorUnsupported(E, "GNU array range designator extension");
1162 if (E->initializesStdInitializerList()) {
1163 EmitStdInitializerList(Dest.getAddr(), E);
1167 AggValueSlot Dest = EnsureSlot(E->getType());
1168 LValue DestLV = CGF.MakeAddrLValue(Dest.getAddr(), E->getType(),
1169 Dest.getAlignment());
1171 // Handle initialization of an array.
1172 if (E->getType()->isArrayType()) {
1173 if (E->isStringLiteralInit())
1174 return Visit(E->getInit(0));
1176 QualType elementType =
1177 CGF.getContext().getAsArrayType(E->getType())->getElementType();
1179 llvm::PointerType *APType =
1180 cast<llvm::PointerType>(Dest.getAddr()->getType());
1181 llvm::ArrayType *AType =
1182 cast<llvm::ArrayType>(APType->getElementType());
1184 EmitArrayInit(Dest.getAddr(), AType, elementType, E);
1188 assert(E->getType()->isRecordType() && "Only support structs/unions here!");
1190 // Do struct initialization; this code just sets each individual member
1191 // to the approprate value. This makes bitfield support automatic;
1192 // the disadvantage is that the generated code is more difficult for
1193 // the optimizer, especially with bitfields.
1194 unsigned NumInitElements = E->getNumInits();
1195 RecordDecl *record = E->getType()->castAs<RecordType>()->getDecl();
1197 // Prepare a 'this' for CXXDefaultInitExprs.
1198 CodeGenFunction::FieldConstructionScope FCS(CGF, Dest.getAddr());
1200 if (record->isUnion()) {
1201 // Only initialize one field of a union. The field itself is
1202 // specified by the initializer list.
1203 if (!E->getInitializedFieldInUnion()) {
1204 // Empty union; we have nothing to do.
1207 // Make sure that it's really an empty and not a failure of
1208 // semantic analysis.
1209 for (RecordDecl::field_iterator Field = record->field_begin(),
1210 FieldEnd = record->field_end();
1211 Field != FieldEnd; ++Field)
1212 assert(Field->isUnnamedBitfield() && "Only unnamed bitfields allowed");
1217 // FIXME: volatility
1218 FieldDecl *Field = E->getInitializedFieldInUnion();
1220 LValue FieldLoc = CGF.EmitLValueForFieldInitialization(DestLV, Field);
1221 if (NumInitElements) {
1222 // Store the initializer into the field
1223 EmitInitializationToLValue(E->getInit(0), FieldLoc);
1225 // Default-initialize to null.
1226 EmitNullInitializationToLValue(FieldLoc);
1232 // We'll need to enter cleanup scopes in case any of the member
1233 // initializers throw an exception.
1234 SmallVector<EHScopeStack::stable_iterator, 16> cleanups;
1235 llvm::Instruction *cleanupDominator = 0;
1237 // Here we iterate over the fields; this makes it simpler to both
1238 // default-initialize fields and skip over unnamed fields.
1239 unsigned curInitIndex = 0;
1240 for (RecordDecl::field_iterator field = record->field_begin(),
1241 fieldEnd = record->field_end();
1242 field != fieldEnd; ++field) {
1243 // We're done once we hit the flexible array member.
1244 if (field->getType()->isIncompleteArrayType())
1247 // Always skip anonymous bitfields.
1248 if (field->isUnnamedBitfield())
1251 // We're done if we reach the end of the explicit initializers, we
1252 // have a zeroed object, and the rest of the fields are
1253 // zero-initializable.
1254 if (curInitIndex == NumInitElements && Dest.isZeroed() &&
1255 CGF.getTypes().isZeroInitializable(E->getType()))
1259 LValue LV = CGF.EmitLValueForFieldInitialization(DestLV, *field);
1260 // We never generate write-barries for initialized fields.
1263 if (curInitIndex < NumInitElements) {
1264 // Store the initializer into the field.
1265 EmitInitializationToLValue(E->getInit(curInitIndex++), LV);
1267 // We're out of initalizers; default-initialize to null
1268 EmitNullInitializationToLValue(LV);
1271 // Push a destructor if necessary.
1272 // FIXME: if we have an array of structures, all explicitly
1273 // initialized, we can end up pushing a linear number of cleanups.
1274 bool pushedCleanup = false;
1275 if (QualType::DestructionKind dtorKind
1276 = field->getType().isDestructedType()) {
1277 assert(LV.isSimple());
1278 if (CGF.needsEHCleanup(dtorKind)) {
1279 if (!cleanupDominator)
1280 cleanupDominator = CGF.Builder.CreateUnreachable(); // placeholder
1282 CGF.pushDestroy(EHCleanup, LV.getAddress(), field->getType(),
1283 CGF.getDestroyer(dtorKind), false);
1284 cleanups.push_back(CGF.EHStack.stable_begin());
1285 pushedCleanup = true;
1289 // If the GEP didn't get used because of a dead zero init or something
1290 // else, clean it up for -O0 builds and general tidiness.
1291 if (!pushedCleanup && LV.isSimple())
1292 if (llvm::GetElementPtrInst *GEP =
1293 dyn_cast<llvm::GetElementPtrInst>(LV.getAddress()))
1294 if (GEP->use_empty())
1295 GEP->eraseFromParent();
1298 // Deactivate all the partial cleanups in reverse order, which
1299 // generally means popping them.
1300 for (unsigned i = cleanups.size(); i != 0; --i)
1301 CGF.DeactivateCleanupBlock(cleanups[i-1], cleanupDominator);
1303 // Destroy the placeholder if we made one.
1304 if (cleanupDominator)
1305 cleanupDominator->eraseFromParent();
1308 //===----------------------------------------------------------------------===//
1309 // Entry Points into this File
1310 //===----------------------------------------------------------------------===//
1312 /// GetNumNonZeroBytesInInit - Get an approximate count of the number of
1313 /// non-zero bytes that will be stored when outputting the initializer for the
1314 /// specified initializer expression.
1315 static CharUnits GetNumNonZeroBytesInInit(const Expr *E, CodeGenFunction &CGF) {
1316 E = E->IgnoreParens();
1318 // 0 and 0.0 won't require any non-zero stores!
1319 if (isSimpleZero(E, CGF)) return CharUnits::Zero();
1321 // If this is an initlist expr, sum up the size of sizes of the (present)
1322 // elements. If this is something weird, assume the whole thing is non-zero.
1323 const InitListExpr *ILE = dyn_cast<InitListExpr>(E);
1324 if (ILE == 0 || !CGF.getTypes().isZeroInitializable(ILE->getType()))
1325 return CGF.getContext().getTypeSizeInChars(E->getType());
1327 // InitListExprs for structs have to be handled carefully. If there are
1328 // reference members, we need to consider the size of the reference, not the
1329 // referencee. InitListExprs for unions and arrays can't have references.
1330 if (const RecordType *RT = E->getType()->getAs<RecordType>()) {
1331 if (!RT->isUnionType()) {
1332 RecordDecl *SD = E->getType()->getAs<RecordType>()->getDecl();
1333 CharUnits NumNonZeroBytes = CharUnits::Zero();
1335 unsigned ILEElement = 0;
1336 for (RecordDecl::field_iterator Field = SD->field_begin(),
1337 FieldEnd = SD->field_end(); Field != FieldEnd; ++Field) {
1338 // We're done once we hit the flexible array member or run out of
1339 // InitListExpr elements.
1340 if (Field->getType()->isIncompleteArrayType() ||
1341 ILEElement == ILE->getNumInits())
1343 if (Field->isUnnamedBitfield())
1346 const Expr *E = ILE->getInit(ILEElement++);
1348 // Reference values are always non-null and have the width of a pointer.
1349 if (Field->getType()->isReferenceType())
1350 NumNonZeroBytes += CGF.getContext().toCharUnitsFromBits(
1351 CGF.getTarget().getPointerWidth(0));
1353 NumNonZeroBytes += GetNumNonZeroBytesInInit(E, CGF);
1356 return NumNonZeroBytes;
1361 CharUnits NumNonZeroBytes = CharUnits::Zero();
1362 for (unsigned i = 0, e = ILE->getNumInits(); i != e; ++i)
1363 NumNonZeroBytes += GetNumNonZeroBytesInInit(ILE->getInit(i), CGF);
1364 return NumNonZeroBytes;
1367 /// CheckAggExprForMemSetUse - If the initializer is large and has a lot of
1368 /// zeros in it, emit a memset and avoid storing the individual zeros.
1370 static void CheckAggExprForMemSetUse(AggValueSlot &Slot, const Expr *E,
1371 CodeGenFunction &CGF) {
1372 // If the slot is already known to be zeroed, nothing to do. Don't mess with
1374 if (Slot.isZeroed() || Slot.isVolatile() || Slot.getAddr() == 0) return;
1376 // C++ objects with a user-declared constructor don't need zero'ing.
1377 if (CGF.getLangOpts().CPlusPlus)
1378 if (const RecordType *RT = CGF.getContext()
1379 .getBaseElementType(E->getType())->getAs<RecordType>()) {
1380 const CXXRecordDecl *RD = cast<CXXRecordDecl>(RT->getDecl());
1381 if (RD->hasUserDeclaredConstructor())
1385 // If the type is 16-bytes or smaller, prefer individual stores over memset.
1386 std::pair<CharUnits, CharUnits> TypeInfo =
1387 CGF.getContext().getTypeInfoInChars(E->getType());
1388 if (TypeInfo.first <= CharUnits::fromQuantity(16))
1391 // Check to see if over 3/4 of the initializer are known to be zero. If so,
1392 // we prefer to emit memset + individual stores for the rest.
1393 CharUnits NumNonZeroBytes = GetNumNonZeroBytesInInit(E, CGF);
1394 if (NumNonZeroBytes*4 > TypeInfo.first)
1397 // Okay, it seems like a good idea to use an initial memset, emit the call.
1398 llvm::Constant *SizeVal = CGF.Builder.getInt64(TypeInfo.first.getQuantity());
1399 CharUnits Align = TypeInfo.second;
1401 llvm::Value *Loc = Slot.getAddr();
1403 Loc = CGF.Builder.CreateBitCast(Loc, CGF.Int8PtrTy);
1404 CGF.Builder.CreateMemSet(Loc, CGF.Builder.getInt8(0), SizeVal,
1405 Align.getQuantity(), false);
1407 // Tell the AggExprEmitter that the slot is known zero.
1414 /// EmitAggExpr - Emit the computation of the specified expression of aggregate
1415 /// type. The result is computed into DestPtr. Note that if DestPtr is null,
1416 /// the value of the aggregate expression is not needed. If VolatileDest is
1417 /// true, DestPtr cannot be 0.
1418 void CodeGenFunction::EmitAggExpr(const Expr *E, AggValueSlot Slot) {
1419 assert(E && hasAggregateEvaluationKind(E->getType()) &&
1420 "Invalid aggregate expression to emit");
1421 assert((Slot.getAddr() != 0 || Slot.isIgnored()) &&
1422 "slot has bits but no address");
1424 // Optimize the slot if possible.
1425 CheckAggExprForMemSetUse(Slot, E, *this);
1427 AggExprEmitter(*this, Slot).Visit(const_cast<Expr*>(E));
1430 LValue CodeGenFunction::EmitAggExprToLValue(const Expr *E) {
1431 assert(hasAggregateEvaluationKind(E->getType()) && "Invalid argument!");
1432 llvm::Value *Temp = CreateMemTemp(E->getType());
1433 LValue LV = MakeAddrLValue(Temp, E->getType());
1434 EmitAggExpr(E, AggValueSlot::forLValue(LV, AggValueSlot::IsNotDestructed,
1435 AggValueSlot::DoesNotNeedGCBarriers,
1436 AggValueSlot::IsNotAliased));
1440 void CodeGenFunction::EmitAggregateCopy(llvm::Value *DestPtr,
1441 llvm::Value *SrcPtr, QualType Ty,
1443 CharUnits alignment,
1444 bool isAssignment) {
1445 assert(!Ty->isAnyComplexType() && "Shouldn't happen for complex");
1447 if (getLangOpts().CPlusPlus) {
1448 if (const RecordType *RT = Ty->getAs<RecordType>()) {
1449 CXXRecordDecl *Record = cast<CXXRecordDecl>(RT->getDecl());
1450 assert((Record->hasTrivialCopyConstructor() ||
1451 Record->hasTrivialCopyAssignment() ||
1452 Record->hasTrivialMoveConstructor() ||
1453 Record->hasTrivialMoveAssignment()) &&
1454 "Trying to aggregate-copy a type without a trivial copy/move "
1455 "constructor or assignment operator");
1456 // Ignore empty classes in C++.
1457 if (Record->isEmpty())
1462 // Aggregate assignment turns into llvm.memcpy. This is almost valid per
1463 // C99 6.5.16.1p3, which states "If the value being stored in an object is
1464 // read from another object that overlaps in anyway the storage of the first
1465 // object, then the overlap shall be exact and the two objects shall have
1466 // qualified or unqualified versions of a compatible type."
1468 // memcpy is not defined if the source and destination pointers are exactly
1469 // equal, but other compilers do this optimization, and almost every memcpy
1470 // implementation handles this case safely. If there is a libc that does not
1471 // safely handle this, we can add a target hook.
1473 // Get data size and alignment info for this aggregate. If this is an
1474 // assignment don't copy the tail padding. Otherwise copying it is fine.
1475 std::pair<CharUnits, CharUnits> TypeInfo;
1477 TypeInfo = getContext().getTypeInfoDataSizeInChars(Ty);
1479 TypeInfo = getContext().getTypeInfoInChars(Ty);
1481 if (alignment.isZero())
1482 alignment = TypeInfo.second;
1484 // FIXME: Handle variable sized types.
1486 // FIXME: If we have a volatile struct, the optimizer can remove what might
1487 // appear to be `extra' memory ops:
1489 // volatile struct { int i; } a, b;
1496 // we need to use a different call here. We use isVolatile to indicate when
1497 // either the source or the destination is volatile.
1499 llvm::PointerType *DPT = cast<llvm::PointerType>(DestPtr->getType());
1501 llvm::Type::getInt8PtrTy(getLLVMContext(), DPT->getAddressSpace());
1502 DestPtr = Builder.CreateBitCast(DestPtr, DBP);
1504 llvm::PointerType *SPT = cast<llvm::PointerType>(SrcPtr->getType());
1506 llvm::Type::getInt8PtrTy(getLLVMContext(), SPT->getAddressSpace());
1507 SrcPtr = Builder.CreateBitCast(SrcPtr, SBP);
1509 // Don't do any of the memmove_collectable tests if GC isn't set.
1510 if (CGM.getLangOpts().getGC() == LangOptions::NonGC) {
1512 } else if (const RecordType *RecordTy = Ty->getAs<RecordType>()) {
1513 RecordDecl *Record = RecordTy->getDecl();
1514 if (Record->hasObjectMember()) {
1515 CharUnits size = TypeInfo.first;
1516 llvm::Type *SizeTy = ConvertType(getContext().getSizeType());
1517 llvm::Value *SizeVal = llvm::ConstantInt::get(SizeTy, size.getQuantity());
1518 CGM.getObjCRuntime().EmitGCMemmoveCollectable(*this, DestPtr, SrcPtr,
1522 } else if (Ty->isArrayType()) {
1523 QualType BaseType = getContext().getBaseElementType(Ty);
1524 if (const RecordType *RecordTy = BaseType->getAs<RecordType>()) {
1525 if (RecordTy->getDecl()->hasObjectMember()) {
1526 CharUnits size = TypeInfo.first;
1527 llvm::Type *SizeTy = ConvertType(getContext().getSizeType());
1528 llvm::Value *SizeVal =
1529 llvm::ConstantInt::get(SizeTy, size.getQuantity());
1530 CGM.getObjCRuntime().EmitGCMemmoveCollectable(*this, DestPtr, SrcPtr,
1537 // Determine the metadata to describe the position of any padding in this
1538 // memcpy, as well as the TBAA tags for the members of the struct, in case
1539 // the optimizer wishes to expand it in to scalar memory operations.
1540 llvm::MDNode *TBAAStructTag = CGM.getTBAAStructInfo(Ty);
1542 Builder.CreateMemCpy(DestPtr, SrcPtr,
1543 llvm::ConstantInt::get(IntPtrTy,
1544 TypeInfo.first.getQuantity()),
1545 alignment.getQuantity(), isVolatile,
1546 /*TBAATag=*/0, TBAAStructTag);
1549 void CodeGenFunction::MaybeEmitStdInitializerListCleanup(llvm::Value *loc,
1551 const ExprWithCleanups *cleanups = dyn_cast<ExprWithCleanups>(init);
1553 init = cleanups->getSubExpr();
1555 if (isa<InitListExpr>(init) &&
1556 cast<InitListExpr>(init)->initializesStdInitializerList()) {
1557 // We initialized this std::initializer_list with an initializer list.
1558 // A backing array was created. Push a cleanup for it.
1559 EmitStdInitializerListCleanup(loc, cast<InitListExpr>(init));
1563 static void EmitRecursiveStdInitializerListCleanup(CodeGenFunction &CGF,
1564 llvm::Value *arrayStart,
1565 const InitListExpr *init) {
1566 // Check if there are any recursive cleanups to do, i.e. if we have
1567 // std::initializer_list<std::initializer_list<obj>> list = {{obj()}};
1568 // then we need to destroy the inner array as well.
1569 for (unsigned i = 0, e = init->getNumInits(); i != e; ++i) {
1570 const InitListExpr *subInit = dyn_cast<InitListExpr>(init->getInit(i));
1571 if (!subInit || !subInit->initializesStdInitializerList())
1574 // This one needs to be destroyed. Get the address of the std::init_list.
1575 llvm::Value *offset = llvm::ConstantInt::get(CGF.SizeTy, i);
1576 llvm::Value *loc = CGF.Builder.CreateInBoundsGEP(arrayStart, offset,
1578 CGF.EmitStdInitializerListCleanup(loc, subInit);
1582 void CodeGenFunction::EmitStdInitializerListCleanup(llvm::Value *loc,
1583 const InitListExpr *init) {
1584 ASTContext &ctx = getContext();
1585 QualType element = GetStdInitializerListElementType(init->getType());
1586 unsigned numInits = init->getNumInits();
1587 llvm::APInt size(ctx.getTypeSize(ctx.getSizeType()), numInits);
1588 QualType array =ctx.getConstantArrayType(element, size, ArrayType::Normal, 0);
1589 QualType arrayPtr = ctx.getPointerType(array);
1590 llvm::Type *arrayPtrType = ConvertType(arrayPtr);
1592 // lvalue is the location of a std::initializer_list, which as its first
1593 // element has a pointer to the array we want to destroy.
1594 llvm::Value *startPointer = Builder.CreateStructGEP(loc, 0, "startPointer");
1595 llvm::Value *startAddress = Builder.CreateLoad(startPointer, "startAddress");
1597 ::EmitRecursiveStdInitializerListCleanup(*this, startAddress, init);
1599 llvm::Value *arrayAddress =
1600 Builder.CreateBitCast(startAddress, arrayPtrType, "arrayAddress");
1601 ::EmitStdInitializerListCleanup(*this, array, arrayAddress, init);