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 //===----------------------------------------------------------------------===//
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 EmitArrayInit(llvm::Value *DestPtr, llvm::ArrayType *AType,
87 QualType elementType, InitListExpr *E);
89 AggValueSlot::NeedsGCBarriers_t needsGC(QualType T) {
90 if (CGF.getLangOpts().getGC() && TypeRequiresGCollection(T))
91 return AggValueSlot::NeedsGCBarriers;
92 return AggValueSlot::DoesNotNeedGCBarriers;
95 bool TypeRequiresGCollection(QualType T);
97 //===--------------------------------------------------------------------===//
99 //===--------------------------------------------------------------------===//
101 void VisitStmt(Stmt *S) {
102 CGF.ErrorUnsupported(S, "aggregate expression");
104 void VisitParenExpr(ParenExpr *PE) { Visit(PE->getSubExpr()); }
105 void VisitGenericSelectionExpr(GenericSelectionExpr *GE) {
106 Visit(GE->getResultExpr());
108 void VisitUnaryExtension(UnaryOperator *E) { Visit(E->getSubExpr()); }
109 void VisitSubstNonTypeTemplateParmExpr(SubstNonTypeTemplateParmExpr *E) {
110 return Visit(E->getReplacement());
114 void VisitDeclRefExpr(DeclRefExpr *E) {
115 // For aggregates, we should always be able to emit the variable
116 // as an l-value unless it's a reference. This is due to the fact
117 // that we can't actually ever see a normal l2r conversion on an
118 // aggregate in C++, and in C there's no language standard
119 // actively preventing us from listing variables in the captures
121 if (E->getDecl()->getType()->isReferenceType()) {
122 if (CodeGenFunction::ConstantEmission result
123 = CGF.tryEmitAsConstant(E)) {
124 EmitFinalDestCopy(E->getType(), result.getReferenceLValue(CGF, E));
129 EmitAggLoadOfLValue(E);
132 void VisitMemberExpr(MemberExpr *ME) { EmitAggLoadOfLValue(ME); }
133 void VisitUnaryDeref(UnaryOperator *E) { EmitAggLoadOfLValue(E); }
134 void VisitStringLiteral(StringLiteral *E) { EmitAggLoadOfLValue(E); }
135 void VisitCompoundLiteralExpr(CompoundLiteralExpr *E);
136 void VisitArraySubscriptExpr(ArraySubscriptExpr *E) {
137 EmitAggLoadOfLValue(E);
139 void VisitPredefinedExpr(const PredefinedExpr *E) {
140 EmitAggLoadOfLValue(E);
144 void VisitCastExpr(CastExpr *E);
145 void VisitCallExpr(const CallExpr *E);
146 void VisitStmtExpr(const StmtExpr *E);
147 void VisitBinaryOperator(const BinaryOperator *BO);
148 void VisitPointerToDataMemberBinaryOperator(const BinaryOperator *BO);
149 void VisitBinAssign(const BinaryOperator *E);
150 void VisitBinComma(const BinaryOperator *E);
152 void VisitObjCMessageExpr(ObjCMessageExpr *E);
153 void VisitObjCIvarRefExpr(ObjCIvarRefExpr *E) {
154 EmitAggLoadOfLValue(E);
157 void VisitAbstractConditionalOperator(const AbstractConditionalOperator *CO);
158 void VisitChooseExpr(const ChooseExpr *CE);
159 void VisitInitListExpr(InitListExpr *E);
160 void VisitImplicitValueInitExpr(ImplicitValueInitExpr *E);
161 void VisitCXXDefaultArgExpr(CXXDefaultArgExpr *DAE) {
162 Visit(DAE->getExpr());
164 void VisitCXXDefaultInitExpr(CXXDefaultInitExpr *DIE) {
165 CodeGenFunction::CXXDefaultInitExprScope Scope(CGF);
166 Visit(DIE->getExpr());
168 void VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E);
169 void VisitCXXConstructExpr(const CXXConstructExpr *E);
170 void VisitLambdaExpr(LambdaExpr *E);
171 void VisitCXXStdInitializerListExpr(CXXStdInitializerListExpr *E);
172 void VisitExprWithCleanups(ExprWithCleanups *E);
173 void VisitCXXScalarValueInitExpr(CXXScalarValueInitExpr *E);
174 void VisitCXXTypeidExpr(CXXTypeidExpr *E) { EmitAggLoadOfLValue(E); }
175 void VisitMaterializeTemporaryExpr(MaterializeTemporaryExpr *E);
176 void VisitOpaqueValueExpr(OpaqueValueExpr *E);
178 void VisitPseudoObjectExpr(PseudoObjectExpr *E) {
179 if (E->isGLValue()) {
180 LValue LV = CGF.EmitPseudoObjectLValue(E);
181 return EmitFinalDestCopy(E->getType(), LV);
184 CGF.EmitPseudoObjectRValue(E, EnsureSlot(E->getType()));
187 void VisitVAArgExpr(VAArgExpr *E);
189 void EmitInitializationToLValue(Expr *E, LValue Address);
190 void EmitNullInitializationToLValue(LValue Address);
191 // case Expr::ChooseExprClass:
192 void VisitCXXThrowExpr(const CXXThrowExpr *E) { CGF.EmitCXXThrowExpr(E); }
193 void VisitAtomicExpr(AtomicExpr *E) {
194 CGF.EmitAtomicExpr(E, EnsureSlot(E->getType()).getAddr());
197 } // end anonymous namespace.
199 //===----------------------------------------------------------------------===//
201 //===----------------------------------------------------------------------===//
203 /// EmitAggLoadOfLValue - Given an expression with aggregate type that
204 /// represents a value lvalue, this method emits the address of the lvalue,
205 /// then loads the result into DestPtr.
206 void AggExprEmitter::EmitAggLoadOfLValue(const Expr *E) {
207 LValue LV = CGF.EmitLValue(E);
209 // If the type of the l-value is atomic, then do an atomic load.
210 if (LV.getType()->isAtomicType()) {
211 CGF.EmitAtomicLoad(LV, E->getExprLoc(), Dest);
215 EmitFinalDestCopy(E->getType(), LV);
218 /// \brief True if the given aggregate type requires special GC API calls.
219 bool AggExprEmitter::TypeRequiresGCollection(QualType T) {
220 // Only record types have members that might require garbage collection.
221 const RecordType *RecordTy = T->getAs<RecordType>();
222 if (!RecordTy) return false;
224 // Don't mess with non-trivial C++ types.
225 RecordDecl *Record = RecordTy->getDecl();
226 if (isa<CXXRecordDecl>(Record) &&
227 (cast<CXXRecordDecl>(Record)->hasNonTrivialCopyConstructor() ||
228 !cast<CXXRecordDecl>(Record)->hasTrivialDestructor()))
231 // Check whether the type has an object member.
232 return Record->hasObjectMember();
235 /// \brief Perform the final move to DestPtr if for some reason
236 /// getReturnValueSlot() didn't use it directly.
238 /// The idea is that you do something like this:
239 /// RValue Result = EmitSomething(..., getReturnValueSlot());
240 /// EmitMoveFromReturnSlot(E, Result);
242 /// If nothing interferes, this will cause the result to be emitted
243 /// directly into the return value slot. Otherwise, a final move
244 /// will be performed.
245 void AggExprEmitter::EmitMoveFromReturnSlot(const Expr *E, RValue src) {
246 if (shouldUseDestForReturnSlot()) {
247 // Logically, Dest.getAddr() should equal Src.getAggregateAddr().
248 // The possibility of undef rvalues complicates that a lot,
249 // though, so we can't really assert.
253 // Otherwise, copy from there to the destination.
254 assert(Dest.getAddr() != src.getAggregateAddr());
255 std::pair<CharUnits, CharUnits> typeInfo =
256 CGF.getContext().getTypeInfoInChars(E->getType());
257 EmitFinalDestCopy(E->getType(), src, typeInfo.second);
260 /// EmitFinalDestCopy - Perform the final copy to DestPtr, if desired.
261 void AggExprEmitter::EmitFinalDestCopy(QualType type, RValue src,
262 CharUnits srcAlign) {
263 assert(src.isAggregate() && "value must be aggregate value!");
264 LValue srcLV = CGF.MakeAddrLValue(src.getAggregateAddr(), type, srcAlign);
265 EmitFinalDestCopy(type, srcLV);
268 /// EmitFinalDestCopy - Perform the final copy to DestPtr, if desired.
269 void AggExprEmitter::EmitFinalDestCopy(QualType type, const LValue &src) {
270 // If Dest is ignored, then we're evaluating an aggregate expression
271 // in a context that doesn't care about the result. Note that loads
272 // from volatile l-values force the existence of a non-ignored
274 if (Dest.isIgnored())
277 AggValueSlot srcAgg =
278 AggValueSlot::forLValue(src, AggValueSlot::IsDestructed,
279 needsGC(type), AggValueSlot::IsAliased);
280 EmitCopy(type, Dest, srcAgg);
283 /// Perform a copy from the source into the destination.
285 /// \param type - the type of the aggregate being copied; qualifiers are
287 void AggExprEmitter::EmitCopy(QualType type, const AggValueSlot &dest,
288 const AggValueSlot &src) {
289 if (dest.requiresGCollection()) {
290 CharUnits sz = CGF.getContext().getTypeSizeInChars(type);
291 llvm::Value *size = llvm::ConstantInt::get(CGF.SizeTy, sz.getQuantity());
292 CGF.CGM.getObjCRuntime().EmitGCMemmoveCollectable(CGF,
299 // If the result of the assignment is used, copy the LHS there also.
300 // It's volatile if either side is. Use the minimum alignment of
302 CGF.EmitAggregateCopy(dest.getAddr(), src.getAddr(), type,
303 dest.isVolatile() || src.isVolatile(),
304 std::min(dest.getAlignment(), src.getAlignment()));
307 /// \brief Emit the initializer for a std::initializer_list initialized with a
308 /// real initializer list.
310 AggExprEmitter::VisitCXXStdInitializerListExpr(CXXStdInitializerListExpr *E) {
311 // Emit an array containing the elements. The array is externally destructed
312 // if the std::initializer_list object is.
313 ASTContext &Ctx = CGF.getContext();
314 LValue Array = CGF.EmitLValue(E->getSubExpr());
315 assert(Array.isSimple() && "initializer_list array not a simple lvalue");
316 llvm::Value *ArrayPtr = Array.getAddress();
318 const ConstantArrayType *ArrayType =
319 Ctx.getAsConstantArrayType(E->getSubExpr()->getType());
320 assert(ArrayType && "std::initializer_list constructed from non-array");
322 // FIXME: Perform the checks on the field types in SemaInit.
323 RecordDecl *Record = E->getType()->castAs<RecordType>()->getDecl();
324 RecordDecl::field_iterator Field = Record->field_begin();
325 if (Field == Record->field_end()) {
326 CGF.ErrorUnsupported(E, "weird std::initializer_list");
331 if (!Field->getType()->isPointerType() ||
332 !Ctx.hasSameType(Field->getType()->getPointeeType(),
333 ArrayType->getElementType())) {
334 CGF.ErrorUnsupported(E, "weird std::initializer_list");
338 AggValueSlot Dest = EnsureSlot(E->getType());
339 LValue DestLV = CGF.MakeAddrLValue(Dest.getAddr(), E->getType(),
340 Dest.getAlignment());
341 LValue Start = CGF.EmitLValueForFieldInitialization(DestLV, *Field);
342 llvm::Value *Zero = llvm::ConstantInt::get(CGF.PtrDiffTy, 0);
343 llvm::Value *IdxStart[] = { Zero, Zero };
344 llvm::Value *ArrayStart =
345 Builder.CreateInBoundsGEP(ArrayPtr, IdxStart, "arraystart");
346 CGF.EmitStoreThroughLValue(RValue::get(ArrayStart), Start);
349 if (Field == Record->field_end()) {
350 CGF.ErrorUnsupported(E, "weird std::initializer_list");
354 llvm::Value *Size = Builder.getInt(ArrayType->getSize());
355 LValue EndOrLength = CGF.EmitLValueForFieldInitialization(DestLV, *Field);
356 if (Field->getType()->isPointerType() &&
357 Ctx.hasSameType(Field->getType()->getPointeeType(),
358 ArrayType->getElementType())) {
360 llvm::Value *IdxEnd[] = { Zero, Size };
361 llvm::Value *ArrayEnd =
362 Builder.CreateInBoundsGEP(ArrayPtr, IdxEnd, "arrayend");
363 CGF.EmitStoreThroughLValue(RValue::get(ArrayEnd), EndOrLength);
364 } else if (Ctx.hasSameType(Field->getType(), Ctx.getSizeType())) {
366 CGF.EmitStoreThroughLValue(RValue::get(Size), EndOrLength);
368 CGF.ErrorUnsupported(E, "weird std::initializer_list");
373 /// \brief Emit initialization of an array from an initializer list.
374 void AggExprEmitter::EmitArrayInit(llvm::Value *DestPtr, llvm::ArrayType *AType,
375 QualType elementType, InitListExpr *E) {
376 uint64_t NumInitElements = E->getNumInits();
378 uint64_t NumArrayElements = AType->getNumElements();
379 assert(NumInitElements <= NumArrayElements);
381 // DestPtr is an array*. Construct an elementType* by drilling
383 llvm::Value *zero = llvm::ConstantInt::get(CGF.SizeTy, 0);
384 llvm::Value *indices[] = { zero, zero };
386 Builder.CreateInBoundsGEP(DestPtr, indices, "arrayinit.begin");
388 // Exception safety requires us to destroy all the
389 // already-constructed members if an initializer throws.
390 // For that, we'll need an EH cleanup.
391 QualType::DestructionKind dtorKind = elementType.isDestructedType();
392 llvm::AllocaInst *endOfInit = 0;
393 EHScopeStack::stable_iterator cleanup;
394 llvm::Instruction *cleanupDominator = 0;
395 if (CGF.needsEHCleanup(dtorKind)) {
396 // In principle we could tell the cleanup where we are more
397 // directly, but the control flow can get so varied here that it
398 // would actually be quite complex. Therefore we go through an
400 endOfInit = CGF.CreateTempAlloca(begin->getType(),
401 "arrayinit.endOfInit");
402 cleanupDominator = Builder.CreateStore(begin, endOfInit);
403 CGF.pushIrregularPartialArrayCleanup(begin, endOfInit, elementType,
404 CGF.getDestroyer(dtorKind));
405 cleanup = CGF.EHStack.stable_begin();
407 // Otherwise, remember that we didn't need a cleanup.
409 dtorKind = QualType::DK_none;
412 llvm::Value *one = llvm::ConstantInt::get(CGF.SizeTy, 1);
414 // The 'current element to initialize'. The invariants on this
415 // variable are complicated. Essentially, after each iteration of
416 // the loop, it points to the last initialized element, except
417 // that it points to the beginning of the array before any
418 // elements have been initialized.
419 llvm::Value *element = begin;
421 // Emit the explicit initializers.
422 for (uint64_t i = 0; i != NumInitElements; ++i) {
423 // Advance to the next element.
425 element = Builder.CreateInBoundsGEP(element, one, "arrayinit.element");
427 // Tell the cleanup that it needs to destroy up to this
428 // element. TODO: some of these stores can be trivially
429 // observed to be unnecessary.
430 if (endOfInit) Builder.CreateStore(element, endOfInit);
433 LValue elementLV = CGF.MakeAddrLValue(element, elementType);
434 EmitInitializationToLValue(E->getInit(i), elementLV);
437 // Check whether there's a non-trivial array-fill expression.
438 // Note that this will be a CXXConstructExpr even if the element
439 // type is an array (or array of array, etc.) of class type.
440 Expr *filler = E->getArrayFiller();
441 bool hasTrivialFiller = true;
442 if (CXXConstructExpr *cons = dyn_cast_or_null<CXXConstructExpr>(filler)) {
443 assert(cons->getConstructor()->isDefaultConstructor());
444 hasTrivialFiller = cons->getConstructor()->isTrivial();
447 // Any remaining elements need to be zero-initialized, possibly
448 // using the filler expression. We can skip this if the we're
449 // emitting to zeroed memory.
450 if (NumInitElements != NumArrayElements &&
451 !(Dest.isZeroed() && hasTrivialFiller &&
452 CGF.getTypes().isZeroInitializable(elementType))) {
454 // Use an actual loop. This is basically
455 // do { *array++ = filler; } while (array != end);
457 // Advance to the start of the rest of the array.
458 if (NumInitElements) {
459 element = Builder.CreateInBoundsGEP(element, one, "arrayinit.start");
460 if (endOfInit) Builder.CreateStore(element, endOfInit);
463 // Compute the end of the array.
464 llvm::Value *end = Builder.CreateInBoundsGEP(begin,
465 llvm::ConstantInt::get(CGF.SizeTy, NumArrayElements),
468 llvm::BasicBlock *entryBB = Builder.GetInsertBlock();
469 llvm::BasicBlock *bodyBB = CGF.createBasicBlock("arrayinit.body");
471 // Jump into the body.
472 CGF.EmitBlock(bodyBB);
473 llvm::PHINode *currentElement =
474 Builder.CreatePHI(element->getType(), 2, "arrayinit.cur");
475 currentElement->addIncoming(element, entryBB);
477 // Emit the actual filler expression.
478 LValue elementLV = CGF.MakeAddrLValue(currentElement, elementType);
480 EmitInitializationToLValue(filler, elementLV);
482 EmitNullInitializationToLValue(elementLV);
484 // Move on to the next element.
485 llvm::Value *nextElement =
486 Builder.CreateInBoundsGEP(currentElement, one, "arrayinit.next");
488 // Tell the EH cleanup that we finished with the last element.
489 if (endOfInit) Builder.CreateStore(nextElement, endOfInit);
491 // Leave the loop if we're done.
492 llvm::Value *done = Builder.CreateICmpEQ(nextElement, end,
494 llvm::BasicBlock *endBB = CGF.createBasicBlock("arrayinit.end");
495 Builder.CreateCondBr(done, endBB, bodyBB);
496 currentElement->addIncoming(nextElement, Builder.GetInsertBlock());
498 CGF.EmitBlock(endBB);
501 // Leave the partial-array cleanup if we entered one.
502 if (dtorKind) CGF.DeactivateCleanupBlock(cleanup, cleanupDominator);
505 //===----------------------------------------------------------------------===//
507 //===----------------------------------------------------------------------===//
509 void AggExprEmitter::VisitMaterializeTemporaryExpr(MaterializeTemporaryExpr *E){
510 Visit(E->GetTemporaryExpr());
513 void AggExprEmitter::VisitOpaqueValueExpr(OpaqueValueExpr *e) {
514 EmitFinalDestCopy(e->getType(), CGF.getOpaqueLValueMapping(e));
518 AggExprEmitter::VisitCompoundLiteralExpr(CompoundLiteralExpr *E) {
519 if (Dest.isPotentiallyAliased() &&
520 E->getType().isPODType(CGF.getContext())) {
521 // For a POD type, just emit a load of the lvalue + a copy, because our
522 // compound literal might alias the destination.
523 EmitAggLoadOfLValue(E);
527 AggValueSlot Slot = EnsureSlot(E->getType());
528 CGF.EmitAggExpr(E->getInitializer(), Slot);
531 /// Attempt to look through various unimportant expressions to find a
532 /// cast of the given kind.
533 static Expr *findPeephole(Expr *op, CastKind kind) {
535 op = op->IgnoreParens();
536 if (CastExpr *castE = dyn_cast<CastExpr>(op)) {
537 if (castE->getCastKind() == kind)
538 return castE->getSubExpr();
539 if (castE->getCastKind() == CK_NoOp)
546 void AggExprEmitter::VisitCastExpr(CastExpr *E) {
547 switch (E->getCastKind()) {
549 // FIXME: Can this actually happen? We have no test coverage for it.
550 assert(isa<CXXDynamicCastExpr>(E) && "CK_Dynamic without a dynamic_cast?");
551 LValue LV = CGF.EmitCheckedLValue(E->getSubExpr(),
552 CodeGenFunction::TCK_Load);
553 // FIXME: Do we also need to handle property references here?
555 CGF.EmitDynamicCast(LV.getAddress(), cast<CXXDynamicCastExpr>(E));
557 CGF.CGM.ErrorUnsupported(E, "non-simple lvalue dynamic_cast");
559 if (!Dest.isIgnored())
560 CGF.CGM.ErrorUnsupported(E, "lvalue dynamic_cast with a destination");
565 if (Dest.isIgnored()) break;
567 // GCC union extension
568 QualType Ty = E->getSubExpr()->getType();
569 QualType PtrTy = CGF.getContext().getPointerType(Ty);
570 llvm::Value *CastPtr = Builder.CreateBitCast(Dest.getAddr(),
571 CGF.ConvertType(PtrTy));
572 EmitInitializationToLValue(E->getSubExpr(),
573 CGF.MakeAddrLValue(CastPtr, Ty));
577 case CK_DerivedToBase:
578 case CK_BaseToDerived:
579 case CK_UncheckedDerivedToBase: {
580 llvm_unreachable("cannot perform hierarchy conversion in EmitAggExpr: "
581 "should have been unpacked before we got here");
584 case CK_NonAtomicToAtomic:
585 case CK_AtomicToNonAtomic: {
586 bool isToAtomic = (E->getCastKind() == CK_NonAtomicToAtomic);
588 // Determine the atomic and value types.
589 QualType atomicType = E->getSubExpr()->getType();
590 QualType valueType = E->getType();
591 if (isToAtomic) std::swap(atomicType, valueType);
593 assert(atomicType->isAtomicType());
594 assert(CGF.getContext().hasSameUnqualifiedType(valueType,
595 atomicType->castAs<AtomicType>()->getValueType()));
597 // Just recurse normally if we're ignoring the result or the
598 // atomic type doesn't change representation.
599 if (Dest.isIgnored() || !CGF.CGM.isPaddedAtomicType(atomicType)) {
600 return Visit(E->getSubExpr());
603 CastKind peepholeTarget =
604 (isToAtomic ? CK_AtomicToNonAtomic : CK_NonAtomicToAtomic);
606 // These two cases are reverses of each other; try to peephole them.
607 if (Expr *op = findPeephole(E->getSubExpr(), peepholeTarget)) {
608 assert(CGF.getContext().hasSameUnqualifiedType(op->getType(),
610 "peephole significantly changed types?");
614 // If we're converting an r-value of non-atomic type to an r-value
615 // of atomic type, just emit directly into the relevant sub-object.
617 AggValueSlot valueDest = Dest;
618 if (!valueDest.isIgnored() && CGF.CGM.isPaddedAtomicType(atomicType)) {
619 // Zero-initialize. (Strictly speaking, we only need to intialize
620 // the padding at the end, but this is simpler.)
621 if (!Dest.isZeroed())
622 CGF.EmitNullInitialization(Dest.getAddr(), atomicType);
624 // Build a GEP to refer to the subobject.
625 llvm::Value *valueAddr =
626 CGF.Builder.CreateStructGEP(valueDest.getAddr(), 0);
627 valueDest = AggValueSlot::forAddr(valueAddr,
628 valueDest.getAlignment(),
629 valueDest.getQualifiers(),
630 valueDest.isExternallyDestructed(),
631 valueDest.requiresGCollection(),
632 valueDest.isPotentiallyAliased(),
633 AggValueSlot::IsZeroed);
636 CGF.EmitAggExpr(E->getSubExpr(), valueDest);
640 // Otherwise, we're converting an atomic type to a non-atomic type.
641 // Make an atomic temporary, emit into that, and then copy the value out.
642 AggValueSlot atomicSlot =
643 CGF.CreateAggTemp(atomicType, "atomic-to-nonatomic.temp");
644 CGF.EmitAggExpr(E->getSubExpr(), atomicSlot);
646 llvm::Value *valueAddr =
647 Builder.CreateStructGEP(atomicSlot.getAddr(), 0);
648 RValue rvalue = RValue::getAggregate(valueAddr, atomicSlot.isVolatile());
649 return EmitFinalDestCopy(valueType, rvalue);
652 case CK_LValueToRValue:
653 // If we're loading from a volatile type, force the destination
655 if (E->getSubExpr()->getType().isVolatileQualified()) {
656 EnsureDest(E->getType());
657 return Visit(E->getSubExpr());
663 case CK_UserDefinedConversion:
664 case CK_ConstructorConversion:
665 assert(CGF.getContext().hasSameUnqualifiedType(E->getSubExpr()->getType(),
667 "Implicit cast types must be compatible");
668 Visit(E->getSubExpr());
671 case CK_LValueBitCast:
672 llvm_unreachable("should not be emitting lvalue bitcast as rvalue");
676 case CK_ArrayToPointerDecay:
677 case CK_FunctionToPointerDecay:
678 case CK_NullToPointer:
679 case CK_NullToMemberPointer:
680 case CK_BaseToDerivedMemberPointer:
681 case CK_DerivedToBaseMemberPointer:
682 case CK_MemberPointerToBoolean:
683 case CK_ReinterpretMemberPointer:
684 case CK_IntegralToPointer:
685 case CK_PointerToIntegral:
686 case CK_PointerToBoolean:
689 case CK_IntegralCast:
690 case CK_IntegralToBoolean:
691 case CK_IntegralToFloating:
692 case CK_FloatingToIntegral:
693 case CK_FloatingToBoolean:
694 case CK_FloatingCast:
695 case CK_CPointerToObjCPointerCast:
696 case CK_BlockPointerToObjCPointerCast:
697 case CK_AnyPointerToBlockPointerCast:
698 case CK_ObjCObjectLValueCast:
699 case CK_FloatingRealToComplex:
700 case CK_FloatingComplexToReal:
701 case CK_FloatingComplexToBoolean:
702 case CK_FloatingComplexCast:
703 case CK_FloatingComplexToIntegralComplex:
704 case CK_IntegralRealToComplex:
705 case CK_IntegralComplexToReal:
706 case CK_IntegralComplexToBoolean:
707 case CK_IntegralComplexCast:
708 case CK_IntegralComplexToFloatingComplex:
709 case CK_ARCProduceObject:
710 case CK_ARCConsumeObject:
711 case CK_ARCReclaimReturnedObject:
712 case CK_ARCExtendBlockObject:
713 case CK_CopyAndAutoreleaseBlockObject:
714 case CK_BuiltinFnToFnPtr:
715 case CK_ZeroToOCLEvent:
716 llvm_unreachable("cast kind invalid for aggregate types");
720 void AggExprEmitter::VisitCallExpr(const CallExpr *E) {
721 if (E->getCallReturnType()->isReferenceType()) {
722 EmitAggLoadOfLValue(E);
726 RValue RV = CGF.EmitCallExpr(E, getReturnValueSlot());
727 EmitMoveFromReturnSlot(E, RV);
730 void AggExprEmitter::VisitObjCMessageExpr(ObjCMessageExpr *E) {
731 RValue RV = CGF.EmitObjCMessageExpr(E, getReturnValueSlot());
732 EmitMoveFromReturnSlot(E, RV);
735 void AggExprEmitter::VisitBinComma(const BinaryOperator *E) {
736 CGF.EmitIgnoredExpr(E->getLHS());
740 void AggExprEmitter::VisitStmtExpr(const StmtExpr *E) {
741 CodeGenFunction::StmtExprEvaluation eval(CGF);
742 CGF.EmitCompoundStmt(*E->getSubStmt(), true, Dest);
745 void AggExprEmitter::VisitBinaryOperator(const BinaryOperator *E) {
746 if (E->getOpcode() == BO_PtrMemD || E->getOpcode() == BO_PtrMemI)
747 VisitPointerToDataMemberBinaryOperator(E);
749 CGF.ErrorUnsupported(E, "aggregate binary expression");
752 void AggExprEmitter::VisitPointerToDataMemberBinaryOperator(
753 const BinaryOperator *E) {
754 LValue LV = CGF.EmitPointerToDataMemberBinaryExpr(E);
755 EmitFinalDestCopy(E->getType(), LV);
758 /// Is the value of the given expression possibly a reference to or
759 /// into a __block variable?
760 static bool isBlockVarRef(const Expr *E) {
761 // Make sure we look through parens.
762 E = E->IgnoreParens();
764 // Check for a direct reference to a __block variable.
765 if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E)) {
766 const VarDecl *var = dyn_cast<VarDecl>(DRE->getDecl());
767 return (var && var->hasAttr<BlocksAttr>());
770 // More complicated stuff.
773 if (const BinaryOperator *op = dyn_cast<BinaryOperator>(E)) {
774 // For an assignment or pointer-to-member operation, just care
776 if (op->isAssignmentOp() || op->isPtrMemOp())
777 return isBlockVarRef(op->getLHS());
779 // For a comma, just care about the RHS.
780 if (op->getOpcode() == BO_Comma)
781 return isBlockVarRef(op->getRHS());
783 // FIXME: pointer arithmetic?
786 // Check both sides of a conditional operator.
787 } else if (const AbstractConditionalOperator *op
788 = dyn_cast<AbstractConditionalOperator>(E)) {
789 return isBlockVarRef(op->getTrueExpr())
790 || isBlockVarRef(op->getFalseExpr());
792 // OVEs are required to support BinaryConditionalOperators.
793 } else if (const OpaqueValueExpr *op
794 = dyn_cast<OpaqueValueExpr>(E)) {
795 if (const Expr *src = op->getSourceExpr())
796 return isBlockVarRef(src);
798 // Casts are necessary to get things like (*(int*)&var) = foo().
799 // We don't really care about the kind of cast here, except
800 // we don't want to look through l2r casts, because it's okay
801 // to get the *value* in a __block variable.
802 } else if (const CastExpr *cast = dyn_cast<CastExpr>(E)) {
803 if (cast->getCastKind() == CK_LValueToRValue)
805 return isBlockVarRef(cast->getSubExpr());
807 // Handle unary operators. Again, just aggressively look through
808 // it, ignoring the operation.
809 } else if (const UnaryOperator *uop = dyn_cast<UnaryOperator>(E)) {
810 return isBlockVarRef(uop->getSubExpr());
812 // Look into the base of a field access.
813 } else if (const MemberExpr *mem = dyn_cast<MemberExpr>(E)) {
814 return isBlockVarRef(mem->getBase());
816 // Look into the base of a subscript.
817 } else if (const ArraySubscriptExpr *sub = dyn_cast<ArraySubscriptExpr>(E)) {
818 return isBlockVarRef(sub->getBase());
824 void AggExprEmitter::VisitBinAssign(const BinaryOperator *E) {
825 // For an assignment to work, the value on the right has
826 // to be compatible with the value on the left.
827 assert(CGF.getContext().hasSameUnqualifiedType(E->getLHS()->getType(),
828 E->getRHS()->getType())
829 && "Invalid assignment");
831 // If the LHS might be a __block variable, and the RHS can
832 // potentially cause a block copy, we need to evaluate the RHS first
833 // so that the assignment goes the right place.
834 // This is pretty semantically fragile.
835 if (isBlockVarRef(E->getLHS()) &&
836 E->getRHS()->HasSideEffects(CGF.getContext())) {
837 // Ensure that we have a destination, and evaluate the RHS into that.
838 EnsureDest(E->getRHS()->getType());
841 // Now emit the LHS and copy into it.
842 LValue LHS = CGF.EmitCheckedLValue(E->getLHS(), CodeGenFunction::TCK_Store);
844 // That copy is an atomic copy if the LHS is atomic.
845 if (LHS.getType()->isAtomicType()) {
846 CGF.EmitAtomicStore(Dest.asRValue(), LHS, /*isInit*/ false);
850 EmitCopy(E->getLHS()->getType(),
851 AggValueSlot::forLValue(LHS, AggValueSlot::IsDestructed,
852 needsGC(E->getLHS()->getType()),
853 AggValueSlot::IsAliased),
858 LValue LHS = CGF.EmitLValue(E->getLHS());
860 // If we have an atomic type, evaluate into the destination and then
861 // do an atomic copy.
862 if (LHS.getType()->isAtomicType()) {
863 EnsureDest(E->getRHS()->getType());
865 CGF.EmitAtomicStore(Dest.asRValue(), LHS, /*isInit*/ false);
869 // Codegen the RHS so that it stores directly into the LHS.
870 AggValueSlot LHSSlot =
871 AggValueSlot::forLValue(LHS, AggValueSlot::IsDestructed,
872 needsGC(E->getLHS()->getType()),
873 AggValueSlot::IsAliased);
874 // A non-volatile aggregate destination might have volatile member.
875 if (!LHSSlot.isVolatile() &&
876 CGF.hasVolatileMember(E->getLHS()->getType()))
877 LHSSlot.setVolatile(true);
879 CGF.EmitAggExpr(E->getRHS(), LHSSlot);
881 // Copy into the destination if the assignment isn't ignored.
882 EmitFinalDestCopy(E->getType(), LHS);
885 void AggExprEmitter::
886 VisitAbstractConditionalOperator(const AbstractConditionalOperator *E) {
887 llvm::BasicBlock *LHSBlock = CGF.createBasicBlock("cond.true");
888 llvm::BasicBlock *RHSBlock = CGF.createBasicBlock("cond.false");
889 llvm::BasicBlock *ContBlock = CGF.createBasicBlock("cond.end");
891 // Bind the common expression if necessary.
892 CodeGenFunction::OpaqueValueMapping binding(CGF, E);
894 CodeGenFunction::ConditionalEvaluation eval(CGF);
895 CGF.EmitBranchOnBoolExpr(E->getCond(), LHSBlock, RHSBlock);
897 // Save whether the destination's lifetime is externally managed.
898 bool isExternallyDestructed = Dest.isExternallyDestructed();
901 CGF.EmitBlock(LHSBlock);
902 Visit(E->getTrueExpr());
905 assert(CGF.HaveInsertPoint() && "expression evaluation ended with no IP!");
906 CGF.Builder.CreateBr(ContBlock);
908 // If the result of an agg expression is unused, then the emission
909 // of the LHS might need to create a destination slot. That's fine
910 // with us, and we can safely emit the RHS into the same slot, but
911 // we shouldn't claim that it's already being destructed.
912 Dest.setExternallyDestructed(isExternallyDestructed);
915 CGF.EmitBlock(RHSBlock);
916 Visit(E->getFalseExpr());
919 CGF.EmitBlock(ContBlock);
922 void AggExprEmitter::VisitChooseExpr(const ChooseExpr *CE) {
923 Visit(CE->getChosenSubExpr());
926 void AggExprEmitter::VisitVAArgExpr(VAArgExpr *VE) {
927 llvm::Value *ArgValue = CGF.EmitVAListRef(VE->getSubExpr());
928 llvm::Value *ArgPtr = CGF.EmitVAArg(ArgValue, VE->getType());
931 CGF.ErrorUnsupported(VE, "aggregate va_arg expression");
935 EmitFinalDestCopy(VE->getType(), CGF.MakeAddrLValue(ArgPtr, VE->getType()));
938 void AggExprEmitter::VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E) {
939 // Ensure that we have a slot, but if we already do, remember
940 // whether it was externally destructed.
941 bool wasExternallyDestructed = Dest.isExternallyDestructed();
942 EnsureDest(E->getType());
944 // We're going to push a destructor if there isn't already one.
945 Dest.setExternallyDestructed();
947 Visit(E->getSubExpr());
949 // Push that destructor we promised.
950 if (!wasExternallyDestructed)
951 CGF.EmitCXXTemporary(E->getTemporary(), E->getType(), Dest.getAddr());
955 AggExprEmitter::VisitCXXConstructExpr(const CXXConstructExpr *E) {
956 AggValueSlot Slot = EnsureSlot(E->getType());
957 CGF.EmitCXXConstructExpr(E, Slot);
961 AggExprEmitter::VisitLambdaExpr(LambdaExpr *E) {
962 AggValueSlot Slot = EnsureSlot(E->getType());
963 CGF.EmitLambdaExpr(E, Slot);
966 void AggExprEmitter::VisitExprWithCleanups(ExprWithCleanups *E) {
967 CGF.enterFullExpression(E);
968 CodeGenFunction::RunCleanupsScope cleanups(CGF);
969 Visit(E->getSubExpr());
972 void AggExprEmitter::VisitCXXScalarValueInitExpr(CXXScalarValueInitExpr *E) {
973 QualType T = E->getType();
974 AggValueSlot Slot = EnsureSlot(T);
975 EmitNullInitializationToLValue(CGF.MakeAddrLValue(Slot.getAddr(), T));
978 void AggExprEmitter::VisitImplicitValueInitExpr(ImplicitValueInitExpr *E) {
979 QualType T = E->getType();
980 AggValueSlot Slot = EnsureSlot(T);
981 EmitNullInitializationToLValue(CGF.MakeAddrLValue(Slot.getAddr(), T));
984 /// isSimpleZero - If emitting this value will obviously just cause a store of
985 /// zero to memory, return true. This can return false if uncertain, so it just
986 /// handles simple cases.
987 static bool isSimpleZero(const Expr *E, CodeGenFunction &CGF) {
988 E = E->IgnoreParens();
991 if (const IntegerLiteral *IL = dyn_cast<IntegerLiteral>(E))
992 return IL->getValue() == 0;
994 if (const FloatingLiteral *FL = dyn_cast<FloatingLiteral>(E))
995 return FL->getValue().isPosZero();
997 if ((isa<ImplicitValueInitExpr>(E) || isa<CXXScalarValueInitExpr>(E)) &&
998 CGF.getTypes().isZeroInitializable(E->getType()))
1000 // (int*)0 - Null pointer expressions.
1001 if (const CastExpr *ICE = dyn_cast<CastExpr>(E))
1002 return ICE->getCastKind() == CK_NullToPointer;
1004 if (const CharacterLiteral *CL = dyn_cast<CharacterLiteral>(E))
1005 return CL->getValue() == 0;
1007 // Otherwise, hard case: conservatively return false.
1013 AggExprEmitter::EmitInitializationToLValue(Expr *E, LValue LV) {
1014 QualType type = LV.getType();
1015 // FIXME: Ignore result?
1016 // FIXME: Are initializers affected by volatile?
1017 if (Dest.isZeroed() && isSimpleZero(E, CGF)) {
1018 // Storing "i32 0" to a zero'd memory location is a noop.
1020 } else if (isa<ImplicitValueInitExpr>(E) || isa<CXXScalarValueInitExpr>(E)) {
1021 return EmitNullInitializationToLValue(LV);
1022 } else if (type->isReferenceType()) {
1023 RValue RV = CGF.EmitReferenceBindingToExpr(E);
1024 return CGF.EmitStoreThroughLValue(RV, LV);
1027 switch (CGF.getEvaluationKind(type)) {
1029 CGF.EmitComplexExprIntoLValue(E, LV, /*isInit*/ true);
1032 CGF.EmitAggExpr(E, AggValueSlot::forLValue(LV,
1033 AggValueSlot::IsDestructed,
1034 AggValueSlot::DoesNotNeedGCBarriers,
1035 AggValueSlot::IsNotAliased,
1039 if (LV.isSimple()) {
1040 CGF.EmitScalarInit(E, /*D=*/0, LV, /*Captured=*/false);
1042 CGF.EmitStoreThroughLValue(RValue::get(CGF.EmitScalarExpr(E)), LV);
1046 llvm_unreachable("bad evaluation kind");
1049 void AggExprEmitter::EmitNullInitializationToLValue(LValue lv) {
1050 QualType type = lv.getType();
1052 // If the destination slot is already zeroed out before the aggregate is
1053 // copied into it, we don't have to emit any zeros here.
1054 if (Dest.isZeroed() && CGF.getTypes().isZeroInitializable(type))
1057 if (CGF.hasScalarEvaluationKind(type)) {
1058 // For non-aggregates, we can store the appropriate null constant.
1059 llvm::Value *null = CGF.CGM.EmitNullConstant(type);
1060 // Note that the following is not equivalent to
1061 // EmitStoreThroughBitfieldLValue for ARC types.
1062 if (lv.isBitField()) {
1063 CGF.EmitStoreThroughBitfieldLValue(RValue::get(null), lv);
1065 assert(lv.isSimple());
1066 CGF.EmitStoreOfScalar(null, lv, /* isInitialization */ true);
1069 // There's a potential optimization opportunity in combining
1070 // memsets; that would be easy for arrays, but relatively
1071 // difficult for structures with the current code.
1072 CGF.EmitNullInitialization(lv.getAddress(), lv.getType());
1076 void AggExprEmitter::VisitInitListExpr(InitListExpr *E) {
1078 // FIXME: Assess perf here? Figure out what cases are worth optimizing here
1079 // (Length of globals? Chunks of zeroed-out space?).
1081 // If we can, prefer a copy from a global; this is a lot less code for long
1082 // globals, and it's easier for the current optimizers to analyze.
1083 if (llvm::Constant* C = CGF.CGM.EmitConstantExpr(E, E->getType(), &CGF)) {
1084 llvm::GlobalVariable* GV =
1085 new llvm::GlobalVariable(CGF.CGM.getModule(), C->getType(), true,
1086 llvm::GlobalValue::InternalLinkage, C, "");
1087 EmitFinalDestCopy(E->getType(), CGF.MakeAddrLValue(GV, E->getType()));
1091 if (E->hadArrayRangeDesignator())
1092 CGF.ErrorUnsupported(E, "GNU array range designator extension");
1094 AggValueSlot Dest = EnsureSlot(E->getType());
1096 LValue DestLV = CGF.MakeAddrLValue(Dest.getAddr(), E->getType(),
1097 Dest.getAlignment());
1099 // Handle initialization of an array.
1100 if (E->getType()->isArrayType()) {
1101 if (E->isStringLiteralInit())
1102 return Visit(E->getInit(0));
1104 QualType elementType =
1105 CGF.getContext().getAsArrayType(E->getType())->getElementType();
1107 llvm::PointerType *APType =
1108 cast<llvm::PointerType>(Dest.getAddr()->getType());
1109 llvm::ArrayType *AType =
1110 cast<llvm::ArrayType>(APType->getElementType());
1112 EmitArrayInit(Dest.getAddr(), AType, elementType, E);
1116 assert(E->getType()->isRecordType() && "Only support structs/unions here!");
1118 // Do struct initialization; this code just sets each individual member
1119 // to the approprate value. This makes bitfield support automatic;
1120 // the disadvantage is that the generated code is more difficult for
1121 // the optimizer, especially with bitfields.
1122 unsigned NumInitElements = E->getNumInits();
1123 RecordDecl *record = E->getType()->castAs<RecordType>()->getDecl();
1125 // Prepare a 'this' for CXXDefaultInitExprs.
1126 CodeGenFunction::FieldConstructionScope FCS(CGF, Dest.getAddr());
1128 if (record->isUnion()) {
1129 // Only initialize one field of a union. The field itself is
1130 // specified by the initializer list.
1131 if (!E->getInitializedFieldInUnion()) {
1132 // Empty union; we have nothing to do.
1135 // Make sure that it's really an empty and not a failure of
1136 // semantic analysis.
1137 for (RecordDecl::field_iterator Field = record->field_begin(),
1138 FieldEnd = record->field_end();
1139 Field != FieldEnd; ++Field)
1140 assert(Field->isUnnamedBitfield() && "Only unnamed bitfields allowed");
1145 // FIXME: volatility
1146 FieldDecl *Field = E->getInitializedFieldInUnion();
1148 LValue FieldLoc = CGF.EmitLValueForFieldInitialization(DestLV, Field);
1149 if (NumInitElements) {
1150 // Store the initializer into the field
1151 EmitInitializationToLValue(E->getInit(0), FieldLoc);
1153 // Default-initialize to null.
1154 EmitNullInitializationToLValue(FieldLoc);
1160 // We'll need to enter cleanup scopes in case any of the member
1161 // initializers throw an exception.
1162 SmallVector<EHScopeStack::stable_iterator, 16> cleanups;
1163 llvm::Instruction *cleanupDominator = 0;
1165 // Here we iterate over the fields; this makes it simpler to both
1166 // default-initialize fields and skip over unnamed fields.
1167 unsigned curInitIndex = 0;
1168 for (RecordDecl::field_iterator field = record->field_begin(),
1169 fieldEnd = record->field_end();
1170 field != fieldEnd; ++field) {
1171 // We're done once we hit the flexible array member.
1172 if (field->getType()->isIncompleteArrayType())
1175 // Always skip anonymous bitfields.
1176 if (field->isUnnamedBitfield())
1179 // We're done if we reach the end of the explicit initializers, we
1180 // have a zeroed object, and the rest of the fields are
1181 // zero-initializable.
1182 if (curInitIndex == NumInitElements && Dest.isZeroed() &&
1183 CGF.getTypes().isZeroInitializable(E->getType()))
1187 LValue LV = CGF.EmitLValueForFieldInitialization(DestLV, *field);
1188 // We never generate write-barries for initialized fields.
1191 if (curInitIndex < NumInitElements) {
1192 // Store the initializer into the field.
1193 EmitInitializationToLValue(E->getInit(curInitIndex++), LV);
1195 // We're out of initalizers; default-initialize to null
1196 EmitNullInitializationToLValue(LV);
1199 // Push a destructor if necessary.
1200 // FIXME: if we have an array of structures, all explicitly
1201 // initialized, we can end up pushing a linear number of cleanups.
1202 bool pushedCleanup = false;
1203 if (QualType::DestructionKind dtorKind
1204 = field->getType().isDestructedType()) {
1205 assert(LV.isSimple());
1206 if (CGF.needsEHCleanup(dtorKind)) {
1207 if (!cleanupDominator)
1208 cleanupDominator = CGF.Builder.CreateUnreachable(); // placeholder
1210 CGF.pushDestroy(EHCleanup, LV.getAddress(), field->getType(),
1211 CGF.getDestroyer(dtorKind), false);
1212 cleanups.push_back(CGF.EHStack.stable_begin());
1213 pushedCleanup = true;
1217 // If the GEP didn't get used because of a dead zero init or something
1218 // else, clean it up for -O0 builds and general tidiness.
1219 if (!pushedCleanup && LV.isSimple())
1220 if (llvm::GetElementPtrInst *GEP =
1221 dyn_cast<llvm::GetElementPtrInst>(LV.getAddress()))
1222 if (GEP->use_empty())
1223 GEP->eraseFromParent();
1226 // Deactivate all the partial cleanups in reverse order, which
1227 // generally means popping them.
1228 for (unsigned i = cleanups.size(); i != 0; --i)
1229 CGF.DeactivateCleanupBlock(cleanups[i-1], cleanupDominator);
1231 // Destroy the placeholder if we made one.
1232 if (cleanupDominator)
1233 cleanupDominator->eraseFromParent();
1236 //===----------------------------------------------------------------------===//
1237 // Entry Points into this File
1238 //===----------------------------------------------------------------------===//
1240 /// GetNumNonZeroBytesInInit - Get an approximate count of the number of
1241 /// non-zero bytes that will be stored when outputting the initializer for the
1242 /// specified initializer expression.
1243 static CharUnits GetNumNonZeroBytesInInit(const Expr *E, CodeGenFunction &CGF) {
1244 E = E->IgnoreParens();
1246 // 0 and 0.0 won't require any non-zero stores!
1247 if (isSimpleZero(E, CGF)) return CharUnits::Zero();
1249 // If this is an initlist expr, sum up the size of sizes of the (present)
1250 // elements. If this is something weird, assume the whole thing is non-zero.
1251 const InitListExpr *ILE = dyn_cast<InitListExpr>(E);
1252 if (ILE == 0 || !CGF.getTypes().isZeroInitializable(ILE->getType()))
1253 return CGF.getContext().getTypeSizeInChars(E->getType());
1255 // InitListExprs for structs have to be handled carefully. If there are
1256 // reference members, we need to consider the size of the reference, not the
1257 // referencee. InitListExprs for unions and arrays can't have references.
1258 if (const RecordType *RT = E->getType()->getAs<RecordType>()) {
1259 if (!RT->isUnionType()) {
1260 RecordDecl *SD = E->getType()->getAs<RecordType>()->getDecl();
1261 CharUnits NumNonZeroBytes = CharUnits::Zero();
1263 unsigned ILEElement = 0;
1264 for (RecordDecl::field_iterator Field = SD->field_begin(),
1265 FieldEnd = SD->field_end(); Field != FieldEnd; ++Field) {
1266 // We're done once we hit the flexible array member or run out of
1267 // InitListExpr elements.
1268 if (Field->getType()->isIncompleteArrayType() ||
1269 ILEElement == ILE->getNumInits())
1271 if (Field->isUnnamedBitfield())
1274 const Expr *E = ILE->getInit(ILEElement++);
1276 // Reference values are always non-null and have the width of a pointer.
1277 if (Field->getType()->isReferenceType())
1278 NumNonZeroBytes += CGF.getContext().toCharUnitsFromBits(
1279 CGF.getTarget().getPointerWidth(0));
1281 NumNonZeroBytes += GetNumNonZeroBytesInInit(E, CGF);
1284 return NumNonZeroBytes;
1289 CharUnits NumNonZeroBytes = CharUnits::Zero();
1290 for (unsigned i = 0, e = ILE->getNumInits(); i != e; ++i)
1291 NumNonZeroBytes += GetNumNonZeroBytesInInit(ILE->getInit(i), CGF);
1292 return NumNonZeroBytes;
1295 /// CheckAggExprForMemSetUse - If the initializer is large and has a lot of
1296 /// zeros in it, emit a memset and avoid storing the individual zeros.
1298 static void CheckAggExprForMemSetUse(AggValueSlot &Slot, const Expr *E,
1299 CodeGenFunction &CGF) {
1300 // If the slot is already known to be zeroed, nothing to do. Don't mess with
1302 if (Slot.isZeroed() || Slot.isVolatile() || Slot.getAddr() == 0) return;
1304 // C++ objects with a user-declared constructor don't need zero'ing.
1305 if (CGF.getLangOpts().CPlusPlus)
1306 if (const RecordType *RT = CGF.getContext()
1307 .getBaseElementType(E->getType())->getAs<RecordType>()) {
1308 const CXXRecordDecl *RD = cast<CXXRecordDecl>(RT->getDecl());
1309 if (RD->hasUserDeclaredConstructor())
1313 // If the type is 16-bytes or smaller, prefer individual stores over memset.
1314 std::pair<CharUnits, CharUnits> TypeInfo =
1315 CGF.getContext().getTypeInfoInChars(E->getType());
1316 if (TypeInfo.first <= CharUnits::fromQuantity(16))
1319 // Check to see if over 3/4 of the initializer are known to be zero. If so,
1320 // we prefer to emit memset + individual stores for the rest.
1321 CharUnits NumNonZeroBytes = GetNumNonZeroBytesInInit(E, CGF);
1322 if (NumNonZeroBytes*4 > TypeInfo.first)
1325 // Okay, it seems like a good idea to use an initial memset, emit the call.
1326 llvm::Constant *SizeVal = CGF.Builder.getInt64(TypeInfo.first.getQuantity());
1327 CharUnits Align = TypeInfo.second;
1329 llvm::Value *Loc = Slot.getAddr();
1331 Loc = CGF.Builder.CreateBitCast(Loc, CGF.Int8PtrTy);
1332 CGF.Builder.CreateMemSet(Loc, CGF.Builder.getInt8(0), SizeVal,
1333 Align.getQuantity(), false);
1335 // Tell the AggExprEmitter that the slot is known zero.
1342 /// EmitAggExpr - Emit the computation of the specified expression of aggregate
1343 /// type. The result is computed into DestPtr. Note that if DestPtr is null,
1344 /// the value of the aggregate expression is not needed. If VolatileDest is
1345 /// true, DestPtr cannot be 0.
1346 void CodeGenFunction::EmitAggExpr(const Expr *E, AggValueSlot Slot) {
1347 assert(E && hasAggregateEvaluationKind(E->getType()) &&
1348 "Invalid aggregate expression to emit");
1349 assert((Slot.getAddr() != 0 || Slot.isIgnored()) &&
1350 "slot has bits but no address");
1352 // Optimize the slot if possible.
1353 CheckAggExprForMemSetUse(Slot, E, *this);
1355 AggExprEmitter(*this, Slot).Visit(const_cast<Expr*>(E));
1358 LValue CodeGenFunction::EmitAggExprToLValue(const Expr *E) {
1359 assert(hasAggregateEvaluationKind(E->getType()) && "Invalid argument!");
1360 llvm::Value *Temp = CreateMemTemp(E->getType());
1361 LValue LV = MakeAddrLValue(Temp, E->getType());
1362 EmitAggExpr(E, AggValueSlot::forLValue(LV, AggValueSlot::IsNotDestructed,
1363 AggValueSlot::DoesNotNeedGCBarriers,
1364 AggValueSlot::IsNotAliased));
1368 void CodeGenFunction::EmitAggregateCopy(llvm::Value *DestPtr,
1369 llvm::Value *SrcPtr, QualType Ty,
1371 CharUnits alignment,
1372 bool isAssignment) {
1373 assert(!Ty->isAnyComplexType() && "Shouldn't happen for complex");
1375 if (getLangOpts().CPlusPlus) {
1376 if (const RecordType *RT = Ty->getAs<RecordType>()) {
1377 CXXRecordDecl *Record = cast<CXXRecordDecl>(RT->getDecl());
1378 assert((Record->hasTrivialCopyConstructor() ||
1379 Record->hasTrivialCopyAssignment() ||
1380 Record->hasTrivialMoveConstructor() ||
1381 Record->hasTrivialMoveAssignment()) &&
1382 "Trying to aggregate-copy a type without a trivial copy/move "
1383 "constructor or assignment operator");
1384 // Ignore empty classes in C++.
1385 if (Record->isEmpty())
1390 // Aggregate assignment turns into llvm.memcpy. This is almost valid per
1391 // C99 6.5.16.1p3, which states "If the value being stored in an object is
1392 // read from another object that overlaps in anyway the storage of the first
1393 // object, then the overlap shall be exact and the two objects shall have
1394 // qualified or unqualified versions of a compatible type."
1396 // memcpy is not defined if the source and destination pointers are exactly
1397 // equal, but other compilers do this optimization, and almost every memcpy
1398 // implementation handles this case safely. If there is a libc that does not
1399 // safely handle this, we can add a target hook.
1401 // Get data size and alignment info for this aggregate. If this is an
1402 // assignment don't copy the tail padding. Otherwise copying it is fine.
1403 std::pair<CharUnits, CharUnits> TypeInfo;
1405 TypeInfo = getContext().getTypeInfoDataSizeInChars(Ty);
1407 TypeInfo = getContext().getTypeInfoInChars(Ty);
1409 if (alignment.isZero())
1410 alignment = TypeInfo.second;
1412 // FIXME: Handle variable sized types.
1414 // FIXME: If we have a volatile struct, the optimizer can remove what might
1415 // appear to be `extra' memory ops:
1417 // volatile struct { int i; } a, b;
1424 // we need to use a different call here. We use isVolatile to indicate when
1425 // either the source or the destination is volatile.
1427 llvm::PointerType *DPT = cast<llvm::PointerType>(DestPtr->getType());
1429 llvm::Type::getInt8PtrTy(getLLVMContext(), DPT->getAddressSpace());
1430 DestPtr = Builder.CreateBitCast(DestPtr, DBP);
1432 llvm::PointerType *SPT = cast<llvm::PointerType>(SrcPtr->getType());
1434 llvm::Type::getInt8PtrTy(getLLVMContext(), SPT->getAddressSpace());
1435 SrcPtr = Builder.CreateBitCast(SrcPtr, SBP);
1437 // Don't do any of the memmove_collectable tests if GC isn't set.
1438 if (CGM.getLangOpts().getGC() == LangOptions::NonGC) {
1440 } else if (const RecordType *RecordTy = Ty->getAs<RecordType>()) {
1441 RecordDecl *Record = RecordTy->getDecl();
1442 if (Record->hasObjectMember()) {
1443 CharUnits size = TypeInfo.first;
1444 llvm::Type *SizeTy = ConvertType(getContext().getSizeType());
1445 llvm::Value *SizeVal = llvm::ConstantInt::get(SizeTy, size.getQuantity());
1446 CGM.getObjCRuntime().EmitGCMemmoveCollectable(*this, DestPtr, SrcPtr,
1450 } else if (Ty->isArrayType()) {
1451 QualType BaseType = getContext().getBaseElementType(Ty);
1452 if (const RecordType *RecordTy = BaseType->getAs<RecordType>()) {
1453 if (RecordTy->getDecl()->hasObjectMember()) {
1454 CharUnits size = TypeInfo.first;
1455 llvm::Type *SizeTy = ConvertType(getContext().getSizeType());
1456 llvm::Value *SizeVal =
1457 llvm::ConstantInt::get(SizeTy, size.getQuantity());
1458 CGM.getObjCRuntime().EmitGCMemmoveCollectable(*this, DestPtr, SrcPtr,
1465 // Determine the metadata to describe the position of any padding in this
1466 // memcpy, as well as the TBAA tags for the members of the struct, in case
1467 // the optimizer wishes to expand it in to scalar memory operations.
1468 llvm::MDNode *TBAAStructTag = CGM.getTBAAStructInfo(Ty);
1470 Builder.CreateMemCpy(DestPtr, SrcPtr,
1471 llvm::ConstantInt::get(IntPtrTy,
1472 TypeInfo.first.getQuantity()),
1473 alignment.getQuantity(), isVolatile,
1474 /*TBAATag=*/0, TBAAStructTag);