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> {
39 /// We want to use 'dest' as the return slot except under two
41 /// - The destination slot requires garbage collection, so we
42 /// need to use the GC API.
43 /// - The destination slot is potentially aliased.
44 bool shouldUseDestForReturnSlot() const {
45 return !(Dest.requiresGCollection() || Dest.isPotentiallyAliased());
48 ReturnValueSlot getReturnValueSlot() const {
49 if (!shouldUseDestForReturnSlot())
50 return ReturnValueSlot();
52 return ReturnValueSlot(Dest.getAddress(), Dest.isVolatile(),
56 AggValueSlot EnsureSlot(QualType T) {
57 if (!Dest.isIgnored()) return Dest;
58 return CGF.CreateAggTemp(T, "agg.tmp.ensured");
60 void EnsureDest(QualType T) {
61 if (!Dest.isIgnored()) return;
62 Dest = CGF.CreateAggTemp(T, "agg.tmp.ensured");
66 AggExprEmitter(CodeGenFunction &cgf, AggValueSlot Dest, bool IsResultUnused)
67 : CGF(cgf), Builder(CGF.Builder), Dest(Dest),
68 IsResultUnused(IsResultUnused) { }
70 //===--------------------------------------------------------------------===//
72 //===--------------------------------------------------------------------===//
74 /// EmitAggLoadOfLValue - Given an expression with aggregate type that
75 /// represents a value lvalue, this method emits the address of the lvalue,
76 /// then loads the result into DestPtr.
77 void EmitAggLoadOfLValue(const Expr *E);
79 /// EmitFinalDestCopy - Perform the final copy to DestPtr, if desired.
80 void EmitFinalDestCopy(QualType type, const LValue &src);
81 void EmitFinalDestCopy(QualType type, RValue src);
82 void EmitCopy(QualType type, const AggValueSlot &dest,
83 const AggValueSlot &src);
85 void EmitMoveFromReturnSlot(const Expr *E, RValue Src);
87 void EmitArrayInit(Address DestPtr, llvm::ArrayType *AType,
88 QualType elementType, InitListExpr *E);
90 AggValueSlot::NeedsGCBarriers_t needsGC(QualType T) {
91 if (CGF.getLangOpts().getGC() && TypeRequiresGCollection(T))
92 return AggValueSlot::NeedsGCBarriers;
93 return AggValueSlot::DoesNotNeedGCBarriers;
96 bool TypeRequiresGCollection(QualType T);
98 //===--------------------------------------------------------------------===//
100 //===--------------------------------------------------------------------===//
102 void Visit(Expr *E) {
103 ApplyDebugLocation DL(CGF, E);
104 StmtVisitor<AggExprEmitter>::Visit(E);
107 void VisitStmt(Stmt *S) {
108 CGF.ErrorUnsupported(S, "aggregate expression");
110 void VisitParenExpr(ParenExpr *PE) { Visit(PE->getSubExpr()); }
111 void VisitGenericSelectionExpr(GenericSelectionExpr *GE) {
112 Visit(GE->getResultExpr());
114 void VisitUnaryExtension(UnaryOperator *E) { Visit(E->getSubExpr()); }
115 void VisitSubstNonTypeTemplateParmExpr(SubstNonTypeTemplateParmExpr *E) {
116 return Visit(E->getReplacement());
120 void VisitDeclRefExpr(DeclRefExpr *E) {
121 // For aggregates, we should always be able to emit the variable
122 // as an l-value unless it's a reference. This is due to the fact
123 // that we can't actually ever see a normal l2r conversion on an
124 // aggregate in C++, and in C there's no language standard
125 // actively preventing us from listing variables in the captures
127 if (E->getDecl()->getType()->isReferenceType()) {
128 if (CodeGenFunction::ConstantEmission result
129 = CGF.tryEmitAsConstant(E)) {
130 EmitFinalDestCopy(E->getType(), result.getReferenceLValue(CGF, E));
135 EmitAggLoadOfLValue(E);
138 void VisitMemberExpr(MemberExpr *ME) { EmitAggLoadOfLValue(ME); }
139 void VisitUnaryDeref(UnaryOperator *E) { EmitAggLoadOfLValue(E); }
140 void VisitStringLiteral(StringLiteral *E) { EmitAggLoadOfLValue(E); }
141 void VisitCompoundLiteralExpr(CompoundLiteralExpr *E);
142 void VisitArraySubscriptExpr(ArraySubscriptExpr *E) {
143 EmitAggLoadOfLValue(E);
145 void VisitPredefinedExpr(const PredefinedExpr *E) {
146 EmitAggLoadOfLValue(E);
150 void VisitCastExpr(CastExpr *E);
151 void VisitCallExpr(const CallExpr *E);
152 void VisitStmtExpr(const StmtExpr *E);
153 void VisitBinaryOperator(const BinaryOperator *BO);
154 void VisitPointerToDataMemberBinaryOperator(const BinaryOperator *BO);
155 void VisitBinAssign(const BinaryOperator *E);
156 void VisitBinComma(const BinaryOperator *E);
158 void VisitObjCMessageExpr(ObjCMessageExpr *E);
159 void VisitObjCIvarRefExpr(ObjCIvarRefExpr *E) {
160 EmitAggLoadOfLValue(E);
163 void VisitDesignatedInitUpdateExpr(DesignatedInitUpdateExpr *E);
164 void VisitAbstractConditionalOperator(const AbstractConditionalOperator *CO);
165 void VisitChooseExpr(const ChooseExpr *CE);
166 void VisitInitListExpr(InitListExpr *E);
167 void VisitArrayInitLoopExpr(const ArrayInitLoopExpr *E,
168 llvm::Value *outerBegin = nullptr);
169 void VisitImplicitValueInitExpr(ImplicitValueInitExpr *E);
170 void VisitNoInitExpr(NoInitExpr *E) { } // Do nothing.
171 void VisitCXXDefaultArgExpr(CXXDefaultArgExpr *DAE) {
172 Visit(DAE->getExpr());
174 void VisitCXXDefaultInitExpr(CXXDefaultInitExpr *DIE) {
175 CodeGenFunction::CXXDefaultInitExprScope Scope(CGF);
176 Visit(DIE->getExpr());
178 void VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E);
179 void VisitCXXConstructExpr(const CXXConstructExpr *E);
180 void VisitCXXInheritedCtorInitExpr(const CXXInheritedCtorInitExpr *E);
181 void VisitLambdaExpr(LambdaExpr *E);
182 void VisitCXXStdInitializerListExpr(CXXStdInitializerListExpr *E);
183 void VisitExprWithCleanups(ExprWithCleanups *E);
184 void VisitCXXScalarValueInitExpr(CXXScalarValueInitExpr *E);
185 void VisitCXXTypeidExpr(CXXTypeidExpr *E) { EmitAggLoadOfLValue(E); }
186 void VisitMaterializeTemporaryExpr(MaterializeTemporaryExpr *E);
187 void VisitOpaqueValueExpr(OpaqueValueExpr *E);
189 void VisitPseudoObjectExpr(PseudoObjectExpr *E) {
190 if (E->isGLValue()) {
191 LValue LV = CGF.EmitPseudoObjectLValue(E);
192 return EmitFinalDestCopy(E->getType(), LV);
195 CGF.EmitPseudoObjectRValue(E, EnsureSlot(E->getType()));
198 void VisitVAArgExpr(VAArgExpr *E);
200 void EmitInitializationToLValue(Expr *E, LValue Address);
201 void EmitNullInitializationToLValue(LValue Address);
202 // case Expr::ChooseExprClass:
203 void VisitCXXThrowExpr(const CXXThrowExpr *E) { CGF.EmitCXXThrowExpr(E); }
204 void VisitAtomicExpr(AtomicExpr *E) {
205 RValue Res = CGF.EmitAtomicExpr(E);
206 EmitFinalDestCopy(E->getType(), Res);
209 } // end anonymous namespace.
211 //===----------------------------------------------------------------------===//
213 //===----------------------------------------------------------------------===//
215 /// EmitAggLoadOfLValue - Given an expression with aggregate type that
216 /// represents a value lvalue, this method emits the address of the lvalue,
217 /// then loads the result into DestPtr.
218 void AggExprEmitter::EmitAggLoadOfLValue(const Expr *E) {
219 LValue LV = CGF.EmitLValue(E);
221 // If the type of the l-value is atomic, then do an atomic load.
222 if (LV.getType()->isAtomicType() || CGF.LValueIsSuitableForInlineAtomic(LV)) {
223 CGF.EmitAtomicLoad(LV, E->getExprLoc(), Dest);
227 EmitFinalDestCopy(E->getType(), LV);
230 /// \brief True if the given aggregate type requires special GC API calls.
231 bool AggExprEmitter::TypeRequiresGCollection(QualType T) {
232 // Only record types have members that might require garbage collection.
233 const RecordType *RecordTy = T->getAs<RecordType>();
234 if (!RecordTy) return false;
236 // Don't mess with non-trivial C++ types.
237 RecordDecl *Record = RecordTy->getDecl();
238 if (isa<CXXRecordDecl>(Record) &&
239 (cast<CXXRecordDecl>(Record)->hasNonTrivialCopyConstructor() ||
240 !cast<CXXRecordDecl>(Record)->hasTrivialDestructor()))
243 // Check whether the type has an object member.
244 return Record->hasObjectMember();
247 /// \brief Perform the final move to DestPtr if for some reason
248 /// getReturnValueSlot() didn't use it directly.
250 /// The idea is that you do something like this:
251 /// RValue Result = EmitSomething(..., getReturnValueSlot());
252 /// EmitMoveFromReturnSlot(E, Result);
254 /// If nothing interferes, this will cause the result to be emitted
255 /// directly into the return value slot. Otherwise, a final move
256 /// will be performed.
257 void AggExprEmitter::EmitMoveFromReturnSlot(const Expr *E, RValue src) {
258 if (shouldUseDestForReturnSlot()) {
259 // Logically, Dest.getAddr() should equal Src.getAggregateAddr().
260 // The possibility of undef rvalues complicates that a lot,
261 // though, so we can't really assert.
265 // Otherwise, copy from there to the destination.
266 assert(Dest.getPointer() != src.getAggregatePointer());
267 EmitFinalDestCopy(E->getType(), src);
270 /// EmitFinalDestCopy - Perform the final copy to DestPtr, if desired.
271 void AggExprEmitter::EmitFinalDestCopy(QualType type, RValue src) {
272 assert(src.isAggregate() && "value must be aggregate value!");
273 LValue srcLV = CGF.MakeAddrLValue(src.getAggregateAddress(), type);
274 EmitFinalDestCopy(type, srcLV);
277 /// EmitFinalDestCopy - Perform the final copy to DestPtr, if desired.
278 void AggExprEmitter::EmitFinalDestCopy(QualType type, const LValue &src) {
279 // If Dest is ignored, then we're evaluating an aggregate expression
280 // in a context that doesn't care about the result. Note that loads
281 // from volatile l-values force the existence of a non-ignored
283 if (Dest.isIgnored())
286 AggValueSlot srcAgg =
287 AggValueSlot::forLValue(src, AggValueSlot::IsDestructed,
288 needsGC(type), AggValueSlot::IsAliased);
289 EmitCopy(type, Dest, srcAgg);
292 /// Perform a copy from the source into the destination.
294 /// \param type - the type of the aggregate being copied; qualifiers are
296 void AggExprEmitter::EmitCopy(QualType type, const AggValueSlot &dest,
297 const AggValueSlot &src) {
298 if (dest.requiresGCollection()) {
299 CharUnits sz = CGF.getContext().getTypeSizeInChars(type);
300 llvm::Value *size = llvm::ConstantInt::get(CGF.SizeTy, sz.getQuantity());
301 CGF.CGM.getObjCRuntime().EmitGCMemmoveCollectable(CGF,
308 // If the result of the assignment is used, copy the LHS there also.
309 // It's volatile if either side is. Use the minimum alignment of
311 CGF.EmitAggregateCopy(dest.getAddress(), src.getAddress(), type,
312 dest.isVolatile() || src.isVolatile());
315 /// \brief Emit the initializer for a std::initializer_list initialized with a
316 /// real initializer list.
318 AggExprEmitter::VisitCXXStdInitializerListExpr(CXXStdInitializerListExpr *E) {
319 // Emit an array containing the elements. The array is externally destructed
320 // if the std::initializer_list object is.
321 ASTContext &Ctx = CGF.getContext();
322 LValue Array = CGF.EmitLValue(E->getSubExpr());
323 assert(Array.isSimple() && "initializer_list array not a simple lvalue");
324 Address ArrayPtr = Array.getAddress();
326 const ConstantArrayType *ArrayType =
327 Ctx.getAsConstantArrayType(E->getSubExpr()->getType());
328 assert(ArrayType && "std::initializer_list constructed from non-array");
330 // FIXME: Perform the checks on the field types in SemaInit.
331 RecordDecl *Record = E->getType()->castAs<RecordType>()->getDecl();
332 RecordDecl::field_iterator Field = Record->field_begin();
333 if (Field == Record->field_end()) {
334 CGF.ErrorUnsupported(E, "weird std::initializer_list");
339 if (!Field->getType()->isPointerType() ||
340 !Ctx.hasSameType(Field->getType()->getPointeeType(),
341 ArrayType->getElementType())) {
342 CGF.ErrorUnsupported(E, "weird std::initializer_list");
346 AggValueSlot Dest = EnsureSlot(E->getType());
347 LValue DestLV = CGF.MakeAddrLValue(Dest.getAddress(), E->getType());
348 LValue Start = CGF.EmitLValueForFieldInitialization(DestLV, *Field);
349 llvm::Value *Zero = llvm::ConstantInt::get(CGF.PtrDiffTy, 0);
350 llvm::Value *IdxStart[] = { Zero, Zero };
351 llvm::Value *ArrayStart =
352 Builder.CreateInBoundsGEP(ArrayPtr.getPointer(), IdxStart, "arraystart");
353 CGF.EmitStoreThroughLValue(RValue::get(ArrayStart), Start);
356 if (Field == Record->field_end()) {
357 CGF.ErrorUnsupported(E, "weird std::initializer_list");
361 llvm::Value *Size = Builder.getInt(ArrayType->getSize());
362 LValue EndOrLength = CGF.EmitLValueForFieldInitialization(DestLV, *Field);
363 if (Field->getType()->isPointerType() &&
364 Ctx.hasSameType(Field->getType()->getPointeeType(),
365 ArrayType->getElementType())) {
367 llvm::Value *IdxEnd[] = { Zero, Size };
368 llvm::Value *ArrayEnd =
369 Builder.CreateInBoundsGEP(ArrayPtr.getPointer(), IdxEnd, "arrayend");
370 CGF.EmitStoreThroughLValue(RValue::get(ArrayEnd), EndOrLength);
371 } else if (Ctx.hasSameType(Field->getType(), Ctx.getSizeType())) {
373 CGF.EmitStoreThroughLValue(RValue::get(Size), EndOrLength);
375 CGF.ErrorUnsupported(E, "weird std::initializer_list");
380 /// \brief Determine if E is a trivial array filler, that is, one that is
381 /// equivalent to zero-initialization.
382 static bool isTrivialFiller(Expr *E) {
386 if (isa<ImplicitValueInitExpr>(E))
389 if (auto *ILE = dyn_cast<InitListExpr>(E)) {
390 if (ILE->getNumInits())
392 return isTrivialFiller(ILE->getArrayFiller());
395 if (auto *Cons = dyn_cast_or_null<CXXConstructExpr>(E))
396 return Cons->getConstructor()->isDefaultConstructor() &&
397 Cons->getConstructor()->isTrivial();
399 // FIXME: Are there other cases where we can avoid emitting an initializer?
403 /// \brief Emit initialization of an array from an initializer list.
404 void AggExprEmitter::EmitArrayInit(Address DestPtr, llvm::ArrayType *AType,
405 QualType elementType, InitListExpr *E) {
406 uint64_t NumInitElements = E->getNumInits();
408 uint64_t NumArrayElements = AType->getNumElements();
409 assert(NumInitElements <= NumArrayElements);
411 // DestPtr is an array*. Construct an elementType* by drilling
413 llvm::Value *zero = llvm::ConstantInt::get(CGF.SizeTy, 0);
414 llvm::Value *indices[] = { zero, zero };
416 Builder.CreateInBoundsGEP(DestPtr.getPointer(), indices, "arrayinit.begin");
418 CharUnits elementSize = CGF.getContext().getTypeSizeInChars(elementType);
419 CharUnits elementAlign =
420 DestPtr.getAlignment().alignmentOfArrayElement(elementSize);
422 // Exception safety requires us to destroy all the
423 // already-constructed members if an initializer throws.
424 // For that, we'll need an EH cleanup.
425 QualType::DestructionKind dtorKind = elementType.isDestructedType();
426 Address endOfInit = Address::invalid();
427 EHScopeStack::stable_iterator cleanup;
428 llvm::Instruction *cleanupDominator = nullptr;
429 if (CGF.needsEHCleanup(dtorKind)) {
430 // In principle we could tell the cleanup where we are more
431 // directly, but the control flow can get so varied here that it
432 // would actually be quite complex. Therefore we go through an
434 endOfInit = CGF.CreateTempAlloca(begin->getType(), CGF.getPointerAlign(),
435 "arrayinit.endOfInit");
436 cleanupDominator = Builder.CreateStore(begin, endOfInit);
437 CGF.pushIrregularPartialArrayCleanup(begin, endOfInit, elementType,
439 CGF.getDestroyer(dtorKind));
440 cleanup = CGF.EHStack.stable_begin();
442 // Otherwise, remember that we didn't need a cleanup.
444 dtorKind = QualType::DK_none;
447 llvm::Value *one = llvm::ConstantInt::get(CGF.SizeTy, 1);
449 // The 'current element to initialize'. The invariants on this
450 // variable are complicated. Essentially, after each iteration of
451 // the loop, it points to the last initialized element, except
452 // that it points to the beginning of the array before any
453 // elements have been initialized.
454 llvm::Value *element = begin;
456 // Emit the explicit initializers.
457 for (uint64_t i = 0; i != NumInitElements; ++i) {
458 // Advance to the next element.
460 element = Builder.CreateInBoundsGEP(element, one, "arrayinit.element");
462 // Tell the cleanup that it needs to destroy up to this
463 // element. TODO: some of these stores can be trivially
464 // observed to be unnecessary.
465 if (endOfInit.isValid()) Builder.CreateStore(element, endOfInit);
469 CGF.MakeAddrLValue(Address(element, elementAlign), elementType);
470 EmitInitializationToLValue(E->getInit(i), elementLV);
473 // Check whether there's a non-trivial array-fill expression.
474 Expr *filler = E->getArrayFiller();
475 bool hasTrivialFiller = isTrivialFiller(filler);
477 // Any remaining elements need to be zero-initialized, possibly
478 // using the filler expression. We can skip this if the we're
479 // emitting to zeroed memory.
480 if (NumInitElements != NumArrayElements &&
481 !(Dest.isZeroed() && hasTrivialFiller &&
482 CGF.getTypes().isZeroInitializable(elementType))) {
484 // Use an actual loop. This is basically
485 // do { *array++ = filler; } while (array != end);
487 // Advance to the start of the rest of the array.
488 if (NumInitElements) {
489 element = Builder.CreateInBoundsGEP(element, one, "arrayinit.start");
490 if (endOfInit.isValid()) Builder.CreateStore(element, endOfInit);
493 // Compute the end of the array.
494 llvm::Value *end = Builder.CreateInBoundsGEP(begin,
495 llvm::ConstantInt::get(CGF.SizeTy, NumArrayElements),
498 llvm::BasicBlock *entryBB = Builder.GetInsertBlock();
499 llvm::BasicBlock *bodyBB = CGF.createBasicBlock("arrayinit.body");
501 // Jump into the body.
502 CGF.EmitBlock(bodyBB);
503 llvm::PHINode *currentElement =
504 Builder.CreatePHI(element->getType(), 2, "arrayinit.cur");
505 currentElement->addIncoming(element, entryBB);
507 // Emit the actual filler expression.
509 CGF.MakeAddrLValue(Address(currentElement, elementAlign), elementType);
511 EmitInitializationToLValue(filler, elementLV);
513 EmitNullInitializationToLValue(elementLV);
515 // Move on to the next element.
516 llvm::Value *nextElement =
517 Builder.CreateInBoundsGEP(currentElement, one, "arrayinit.next");
519 // Tell the EH cleanup that we finished with the last element.
520 if (endOfInit.isValid()) Builder.CreateStore(nextElement, endOfInit);
522 // Leave the loop if we're done.
523 llvm::Value *done = Builder.CreateICmpEQ(nextElement, end,
525 llvm::BasicBlock *endBB = CGF.createBasicBlock("arrayinit.end");
526 Builder.CreateCondBr(done, endBB, bodyBB);
527 currentElement->addIncoming(nextElement, Builder.GetInsertBlock());
529 CGF.EmitBlock(endBB);
532 // Leave the partial-array cleanup if we entered one.
533 if (dtorKind) CGF.DeactivateCleanupBlock(cleanup, cleanupDominator);
536 //===----------------------------------------------------------------------===//
538 //===----------------------------------------------------------------------===//
540 void AggExprEmitter::VisitMaterializeTemporaryExpr(MaterializeTemporaryExpr *E){
541 Visit(E->GetTemporaryExpr());
544 void AggExprEmitter::VisitOpaqueValueExpr(OpaqueValueExpr *e) {
545 EmitFinalDestCopy(e->getType(), CGF.getOpaqueLValueMapping(e));
549 AggExprEmitter::VisitCompoundLiteralExpr(CompoundLiteralExpr *E) {
550 if (Dest.isPotentiallyAliased() &&
551 E->getType().isPODType(CGF.getContext())) {
552 // For a POD type, just emit a load of the lvalue + a copy, because our
553 // compound literal might alias the destination.
554 EmitAggLoadOfLValue(E);
558 AggValueSlot Slot = EnsureSlot(E->getType());
559 CGF.EmitAggExpr(E->getInitializer(), Slot);
562 /// Attempt to look through various unimportant expressions to find a
563 /// cast of the given kind.
564 static Expr *findPeephole(Expr *op, CastKind kind) {
566 op = op->IgnoreParens();
567 if (CastExpr *castE = dyn_cast<CastExpr>(op)) {
568 if (castE->getCastKind() == kind)
569 return castE->getSubExpr();
570 if (castE->getCastKind() == CK_NoOp)
577 void AggExprEmitter::VisitCastExpr(CastExpr *E) {
578 if (const auto *ECE = dyn_cast<ExplicitCastExpr>(E))
579 CGF.CGM.EmitExplicitCastExprType(ECE, &CGF);
580 switch (E->getCastKind()) {
582 // FIXME: Can this actually happen? We have no test coverage for it.
583 assert(isa<CXXDynamicCastExpr>(E) && "CK_Dynamic without a dynamic_cast?");
584 LValue LV = CGF.EmitCheckedLValue(E->getSubExpr(),
585 CodeGenFunction::TCK_Load);
586 // FIXME: Do we also need to handle property references here?
588 CGF.EmitDynamicCast(LV.getAddress(), cast<CXXDynamicCastExpr>(E));
590 CGF.CGM.ErrorUnsupported(E, "non-simple lvalue dynamic_cast");
592 if (!Dest.isIgnored())
593 CGF.CGM.ErrorUnsupported(E, "lvalue dynamic_cast with a destination");
598 // Evaluate even if the destination is ignored.
599 if (Dest.isIgnored()) {
600 CGF.EmitAnyExpr(E->getSubExpr(), AggValueSlot::ignored(),
601 /*ignoreResult=*/true);
605 // GCC union extension
606 QualType Ty = E->getSubExpr()->getType();
608 Builder.CreateElementBitCast(Dest.getAddress(), CGF.ConvertType(Ty));
609 EmitInitializationToLValue(E->getSubExpr(),
610 CGF.MakeAddrLValue(CastPtr, Ty));
614 case CK_DerivedToBase:
615 case CK_BaseToDerived:
616 case CK_UncheckedDerivedToBase: {
617 llvm_unreachable("cannot perform hierarchy conversion in EmitAggExpr: "
618 "should have been unpacked before we got here");
621 case CK_NonAtomicToAtomic:
622 case CK_AtomicToNonAtomic: {
623 bool isToAtomic = (E->getCastKind() == CK_NonAtomicToAtomic);
625 // Determine the atomic and value types.
626 QualType atomicType = E->getSubExpr()->getType();
627 QualType valueType = E->getType();
628 if (isToAtomic) std::swap(atomicType, valueType);
630 assert(atomicType->isAtomicType());
631 assert(CGF.getContext().hasSameUnqualifiedType(valueType,
632 atomicType->castAs<AtomicType>()->getValueType()));
634 // Just recurse normally if we're ignoring the result or the
635 // atomic type doesn't change representation.
636 if (Dest.isIgnored() || !CGF.CGM.isPaddedAtomicType(atomicType)) {
637 return Visit(E->getSubExpr());
640 CastKind peepholeTarget =
641 (isToAtomic ? CK_AtomicToNonAtomic : CK_NonAtomicToAtomic);
643 // These two cases are reverses of each other; try to peephole them.
644 if (Expr *op = findPeephole(E->getSubExpr(), peepholeTarget)) {
645 assert(CGF.getContext().hasSameUnqualifiedType(op->getType(),
647 "peephole significantly changed types?");
651 // If we're converting an r-value of non-atomic type to an r-value
652 // of atomic type, just emit directly into the relevant sub-object.
654 AggValueSlot valueDest = Dest;
655 if (!valueDest.isIgnored() && CGF.CGM.isPaddedAtomicType(atomicType)) {
656 // Zero-initialize. (Strictly speaking, we only need to intialize
657 // the padding at the end, but this is simpler.)
658 if (!Dest.isZeroed())
659 CGF.EmitNullInitialization(Dest.getAddress(), atomicType);
661 // Build a GEP to refer to the subobject.
663 CGF.Builder.CreateStructGEP(valueDest.getAddress(), 0,
665 valueDest = AggValueSlot::forAddr(valueAddr,
666 valueDest.getQualifiers(),
667 valueDest.isExternallyDestructed(),
668 valueDest.requiresGCollection(),
669 valueDest.isPotentiallyAliased(),
670 AggValueSlot::IsZeroed);
673 CGF.EmitAggExpr(E->getSubExpr(), valueDest);
677 // Otherwise, we're converting an atomic type to a non-atomic type.
678 // Make an atomic temporary, emit into that, and then copy the value out.
679 AggValueSlot atomicSlot =
680 CGF.CreateAggTemp(atomicType, "atomic-to-nonatomic.temp");
681 CGF.EmitAggExpr(E->getSubExpr(), atomicSlot);
684 Builder.CreateStructGEP(atomicSlot.getAddress(), 0, CharUnits());
685 RValue rvalue = RValue::getAggregate(valueAddr, atomicSlot.isVolatile());
686 return EmitFinalDestCopy(valueType, rvalue);
689 case CK_LValueToRValue:
690 // If we're loading from a volatile type, force the destination
692 if (E->getSubExpr()->getType().isVolatileQualified()) {
693 EnsureDest(E->getType());
694 return Visit(E->getSubExpr());
700 case CK_UserDefinedConversion:
701 case CK_ConstructorConversion:
702 assert(CGF.getContext().hasSameUnqualifiedType(E->getSubExpr()->getType(),
704 "Implicit cast types must be compatible");
705 Visit(E->getSubExpr());
708 case CK_LValueBitCast:
709 llvm_unreachable("should not be emitting lvalue bitcast as rvalue");
713 case CK_ArrayToPointerDecay:
714 case CK_FunctionToPointerDecay:
715 case CK_NullToPointer:
716 case CK_NullToMemberPointer:
717 case CK_BaseToDerivedMemberPointer:
718 case CK_DerivedToBaseMemberPointer:
719 case CK_MemberPointerToBoolean:
720 case CK_ReinterpretMemberPointer:
721 case CK_IntegralToPointer:
722 case CK_PointerToIntegral:
723 case CK_PointerToBoolean:
726 case CK_IntegralCast:
727 case CK_BooleanToSignedIntegral:
728 case CK_IntegralToBoolean:
729 case CK_IntegralToFloating:
730 case CK_FloatingToIntegral:
731 case CK_FloatingToBoolean:
732 case CK_FloatingCast:
733 case CK_CPointerToObjCPointerCast:
734 case CK_BlockPointerToObjCPointerCast:
735 case CK_AnyPointerToBlockPointerCast:
736 case CK_ObjCObjectLValueCast:
737 case CK_FloatingRealToComplex:
738 case CK_FloatingComplexToReal:
739 case CK_FloatingComplexToBoolean:
740 case CK_FloatingComplexCast:
741 case CK_FloatingComplexToIntegralComplex:
742 case CK_IntegralRealToComplex:
743 case CK_IntegralComplexToReal:
744 case CK_IntegralComplexToBoolean:
745 case CK_IntegralComplexCast:
746 case CK_IntegralComplexToFloatingComplex:
747 case CK_ARCProduceObject:
748 case CK_ARCConsumeObject:
749 case CK_ARCReclaimReturnedObject:
750 case CK_ARCExtendBlockObject:
751 case CK_CopyAndAutoreleaseBlockObject:
752 case CK_BuiltinFnToFnPtr:
753 case CK_ZeroToOCLEvent:
754 case CK_ZeroToOCLQueue:
755 case CK_AddressSpaceConversion:
756 case CK_IntToOCLSampler:
757 llvm_unreachable("cast kind invalid for aggregate types");
761 void AggExprEmitter::VisitCallExpr(const CallExpr *E) {
762 if (E->getCallReturnType(CGF.getContext())->isReferenceType()) {
763 EmitAggLoadOfLValue(E);
767 RValue RV = CGF.EmitCallExpr(E, getReturnValueSlot());
768 EmitMoveFromReturnSlot(E, RV);
771 void AggExprEmitter::VisitObjCMessageExpr(ObjCMessageExpr *E) {
772 RValue RV = CGF.EmitObjCMessageExpr(E, getReturnValueSlot());
773 EmitMoveFromReturnSlot(E, RV);
776 void AggExprEmitter::VisitBinComma(const BinaryOperator *E) {
777 CGF.EmitIgnoredExpr(E->getLHS());
781 void AggExprEmitter::VisitStmtExpr(const StmtExpr *E) {
782 CodeGenFunction::StmtExprEvaluation eval(CGF);
783 CGF.EmitCompoundStmt(*E->getSubStmt(), true, Dest);
786 void AggExprEmitter::VisitBinaryOperator(const BinaryOperator *E) {
787 if (E->getOpcode() == BO_PtrMemD || E->getOpcode() == BO_PtrMemI)
788 VisitPointerToDataMemberBinaryOperator(E);
790 CGF.ErrorUnsupported(E, "aggregate binary expression");
793 void AggExprEmitter::VisitPointerToDataMemberBinaryOperator(
794 const BinaryOperator *E) {
795 LValue LV = CGF.EmitPointerToDataMemberBinaryExpr(E);
796 EmitFinalDestCopy(E->getType(), LV);
799 /// Is the value of the given expression possibly a reference to or
800 /// into a __block variable?
801 static bool isBlockVarRef(const Expr *E) {
802 // Make sure we look through parens.
803 E = E->IgnoreParens();
805 // Check for a direct reference to a __block variable.
806 if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E)) {
807 const VarDecl *var = dyn_cast<VarDecl>(DRE->getDecl());
808 return (var && var->hasAttr<BlocksAttr>());
811 // More complicated stuff.
814 if (const BinaryOperator *op = dyn_cast<BinaryOperator>(E)) {
815 // For an assignment or pointer-to-member operation, just care
817 if (op->isAssignmentOp() || op->isPtrMemOp())
818 return isBlockVarRef(op->getLHS());
820 // For a comma, just care about the RHS.
821 if (op->getOpcode() == BO_Comma)
822 return isBlockVarRef(op->getRHS());
824 // FIXME: pointer arithmetic?
827 // Check both sides of a conditional operator.
828 } else if (const AbstractConditionalOperator *op
829 = dyn_cast<AbstractConditionalOperator>(E)) {
830 return isBlockVarRef(op->getTrueExpr())
831 || isBlockVarRef(op->getFalseExpr());
833 // OVEs are required to support BinaryConditionalOperators.
834 } else if (const OpaqueValueExpr *op
835 = dyn_cast<OpaqueValueExpr>(E)) {
836 if (const Expr *src = op->getSourceExpr())
837 return isBlockVarRef(src);
839 // Casts are necessary to get things like (*(int*)&var) = foo().
840 // We don't really care about the kind of cast here, except
841 // we don't want to look through l2r casts, because it's okay
842 // to get the *value* in a __block variable.
843 } else if (const CastExpr *cast = dyn_cast<CastExpr>(E)) {
844 if (cast->getCastKind() == CK_LValueToRValue)
846 return isBlockVarRef(cast->getSubExpr());
848 // Handle unary operators. Again, just aggressively look through
849 // it, ignoring the operation.
850 } else if (const UnaryOperator *uop = dyn_cast<UnaryOperator>(E)) {
851 return isBlockVarRef(uop->getSubExpr());
853 // Look into the base of a field access.
854 } else if (const MemberExpr *mem = dyn_cast<MemberExpr>(E)) {
855 return isBlockVarRef(mem->getBase());
857 // Look into the base of a subscript.
858 } else if (const ArraySubscriptExpr *sub = dyn_cast<ArraySubscriptExpr>(E)) {
859 return isBlockVarRef(sub->getBase());
865 void AggExprEmitter::VisitBinAssign(const BinaryOperator *E) {
866 // For an assignment to work, the value on the right has
867 // to be compatible with the value on the left.
868 assert(CGF.getContext().hasSameUnqualifiedType(E->getLHS()->getType(),
869 E->getRHS()->getType())
870 && "Invalid assignment");
872 // If the LHS might be a __block variable, and the RHS can
873 // potentially cause a block copy, we need to evaluate the RHS first
874 // so that the assignment goes the right place.
875 // This is pretty semantically fragile.
876 if (isBlockVarRef(E->getLHS()) &&
877 E->getRHS()->HasSideEffects(CGF.getContext())) {
878 // Ensure that we have a destination, and evaluate the RHS into that.
879 EnsureDest(E->getRHS()->getType());
882 // Now emit the LHS and copy into it.
883 LValue LHS = CGF.EmitCheckedLValue(E->getLHS(), CodeGenFunction::TCK_Store);
885 // That copy is an atomic copy if the LHS is atomic.
886 if (LHS.getType()->isAtomicType() ||
887 CGF.LValueIsSuitableForInlineAtomic(LHS)) {
888 CGF.EmitAtomicStore(Dest.asRValue(), LHS, /*isInit*/ false);
892 EmitCopy(E->getLHS()->getType(),
893 AggValueSlot::forLValue(LHS, AggValueSlot::IsDestructed,
894 needsGC(E->getLHS()->getType()),
895 AggValueSlot::IsAliased),
900 LValue LHS = CGF.EmitLValue(E->getLHS());
902 // If we have an atomic type, evaluate into the destination and then
903 // do an atomic copy.
904 if (LHS.getType()->isAtomicType() ||
905 CGF.LValueIsSuitableForInlineAtomic(LHS)) {
906 EnsureDest(E->getRHS()->getType());
908 CGF.EmitAtomicStore(Dest.asRValue(), LHS, /*isInit*/ false);
912 // Codegen the RHS so that it stores directly into the LHS.
913 AggValueSlot LHSSlot =
914 AggValueSlot::forLValue(LHS, AggValueSlot::IsDestructed,
915 needsGC(E->getLHS()->getType()),
916 AggValueSlot::IsAliased);
917 // A non-volatile aggregate destination might have volatile member.
918 if (!LHSSlot.isVolatile() &&
919 CGF.hasVolatileMember(E->getLHS()->getType()))
920 LHSSlot.setVolatile(true);
922 CGF.EmitAggExpr(E->getRHS(), LHSSlot);
924 // Copy into the destination if the assignment isn't ignored.
925 EmitFinalDestCopy(E->getType(), LHS);
928 void AggExprEmitter::
929 VisitAbstractConditionalOperator(const AbstractConditionalOperator *E) {
930 llvm::BasicBlock *LHSBlock = CGF.createBasicBlock("cond.true");
931 llvm::BasicBlock *RHSBlock = CGF.createBasicBlock("cond.false");
932 llvm::BasicBlock *ContBlock = CGF.createBasicBlock("cond.end");
934 // Bind the common expression if necessary.
935 CodeGenFunction::OpaqueValueMapping binding(CGF, E);
937 CodeGenFunction::ConditionalEvaluation eval(CGF);
938 CGF.EmitBranchOnBoolExpr(E->getCond(), LHSBlock, RHSBlock,
939 CGF.getProfileCount(E));
941 // Save whether the destination's lifetime is externally managed.
942 bool isExternallyDestructed = Dest.isExternallyDestructed();
945 CGF.EmitBlock(LHSBlock);
946 CGF.incrementProfileCounter(E);
947 Visit(E->getTrueExpr());
950 assert(CGF.HaveInsertPoint() && "expression evaluation ended with no IP!");
951 CGF.Builder.CreateBr(ContBlock);
953 // If the result of an agg expression is unused, then the emission
954 // of the LHS might need to create a destination slot. That's fine
955 // with us, and we can safely emit the RHS into the same slot, but
956 // we shouldn't claim that it's already being destructed.
957 Dest.setExternallyDestructed(isExternallyDestructed);
960 CGF.EmitBlock(RHSBlock);
961 Visit(E->getFalseExpr());
964 CGF.EmitBlock(ContBlock);
967 void AggExprEmitter::VisitChooseExpr(const ChooseExpr *CE) {
968 Visit(CE->getChosenSubExpr());
971 void AggExprEmitter::VisitVAArgExpr(VAArgExpr *VE) {
972 Address ArgValue = Address::invalid();
973 Address ArgPtr = CGF.EmitVAArg(VE, ArgValue);
975 // If EmitVAArg fails, emit an error.
976 if (!ArgPtr.isValid()) {
977 CGF.ErrorUnsupported(VE, "aggregate va_arg expression");
981 EmitFinalDestCopy(VE->getType(), CGF.MakeAddrLValue(ArgPtr, VE->getType()));
984 void AggExprEmitter::VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E) {
985 // Ensure that we have a slot, but if we already do, remember
986 // whether it was externally destructed.
987 bool wasExternallyDestructed = Dest.isExternallyDestructed();
988 EnsureDest(E->getType());
990 // We're going to push a destructor if there isn't already one.
991 Dest.setExternallyDestructed();
993 Visit(E->getSubExpr());
995 // Push that destructor we promised.
996 if (!wasExternallyDestructed)
997 CGF.EmitCXXTemporary(E->getTemporary(), E->getType(), Dest.getAddress());
1001 AggExprEmitter::VisitCXXConstructExpr(const CXXConstructExpr *E) {
1002 AggValueSlot Slot = EnsureSlot(E->getType());
1003 CGF.EmitCXXConstructExpr(E, Slot);
1006 void AggExprEmitter::VisitCXXInheritedCtorInitExpr(
1007 const CXXInheritedCtorInitExpr *E) {
1008 AggValueSlot Slot = EnsureSlot(E->getType());
1009 CGF.EmitInheritedCXXConstructorCall(
1010 E->getConstructor(), E->constructsVBase(), Slot.getAddress(),
1011 E->inheritedFromVBase(), E);
1015 AggExprEmitter::VisitLambdaExpr(LambdaExpr *E) {
1016 AggValueSlot Slot = EnsureSlot(E->getType());
1017 CGF.EmitLambdaExpr(E, Slot);
1020 void AggExprEmitter::VisitExprWithCleanups(ExprWithCleanups *E) {
1021 CGF.enterFullExpression(E);
1022 CodeGenFunction::RunCleanupsScope cleanups(CGF);
1023 Visit(E->getSubExpr());
1026 void AggExprEmitter::VisitCXXScalarValueInitExpr(CXXScalarValueInitExpr *E) {
1027 QualType T = E->getType();
1028 AggValueSlot Slot = EnsureSlot(T);
1029 EmitNullInitializationToLValue(CGF.MakeAddrLValue(Slot.getAddress(), T));
1032 void AggExprEmitter::VisitImplicitValueInitExpr(ImplicitValueInitExpr *E) {
1033 QualType T = E->getType();
1034 AggValueSlot Slot = EnsureSlot(T);
1035 EmitNullInitializationToLValue(CGF.MakeAddrLValue(Slot.getAddress(), T));
1038 /// isSimpleZero - If emitting this value will obviously just cause a store of
1039 /// zero to memory, return true. This can return false if uncertain, so it just
1040 /// handles simple cases.
1041 static bool isSimpleZero(const Expr *E, CodeGenFunction &CGF) {
1042 E = E->IgnoreParens();
1045 if (const IntegerLiteral *IL = dyn_cast<IntegerLiteral>(E))
1046 return IL->getValue() == 0;
1048 if (const FloatingLiteral *FL = dyn_cast<FloatingLiteral>(E))
1049 return FL->getValue().isPosZero();
1051 if ((isa<ImplicitValueInitExpr>(E) || isa<CXXScalarValueInitExpr>(E)) &&
1052 CGF.getTypes().isZeroInitializable(E->getType()))
1054 // (int*)0 - Null pointer expressions.
1055 if (const CastExpr *ICE = dyn_cast<CastExpr>(E))
1056 return ICE->getCastKind() == CK_NullToPointer &&
1057 CGF.getTypes().isPointerZeroInitializable(E->getType());
1059 if (const CharacterLiteral *CL = dyn_cast<CharacterLiteral>(E))
1060 return CL->getValue() == 0;
1062 // Otherwise, hard case: conservatively return false.
1068 AggExprEmitter::EmitInitializationToLValue(Expr *E, LValue LV) {
1069 QualType type = LV.getType();
1070 // FIXME: Ignore result?
1071 // FIXME: Are initializers affected by volatile?
1072 if (Dest.isZeroed() && isSimpleZero(E, CGF)) {
1073 // Storing "i32 0" to a zero'd memory location is a noop.
1075 } else if (isa<ImplicitValueInitExpr>(E) || isa<CXXScalarValueInitExpr>(E)) {
1076 return EmitNullInitializationToLValue(LV);
1077 } else if (isa<NoInitExpr>(E)) {
1080 } else if (type->isReferenceType()) {
1081 RValue RV = CGF.EmitReferenceBindingToExpr(E);
1082 return CGF.EmitStoreThroughLValue(RV, LV);
1085 switch (CGF.getEvaluationKind(type)) {
1087 CGF.EmitComplexExprIntoLValue(E, LV, /*isInit*/ true);
1090 CGF.EmitAggExpr(E, AggValueSlot::forLValue(LV,
1091 AggValueSlot::IsDestructed,
1092 AggValueSlot::DoesNotNeedGCBarriers,
1093 AggValueSlot::IsNotAliased,
1097 if (LV.isSimple()) {
1098 CGF.EmitScalarInit(E, /*D=*/nullptr, LV, /*Captured=*/false);
1100 CGF.EmitStoreThroughLValue(RValue::get(CGF.EmitScalarExpr(E)), LV);
1104 llvm_unreachable("bad evaluation kind");
1107 void AggExprEmitter::EmitNullInitializationToLValue(LValue lv) {
1108 QualType type = lv.getType();
1110 // If the destination slot is already zeroed out before the aggregate is
1111 // copied into it, we don't have to emit any zeros here.
1112 if (Dest.isZeroed() && CGF.getTypes().isZeroInitializable(type))
1115 if (CGF.hasScalarEvaluationKind(type)) {
1116 // For non-aggregates, we can store the appropriate null constant.
1117 llvm::Value *null = CGF.CGM.EmitNullConstant(type);
1118 // Note that the following is not equivalent to
1119 // EmitStoreThroughBitfieldLValue for ARC types.
1120 if (lv.isBitField()) {
1121 CGF.EmitStoreThroughBitfieldLValue(RValue::get(null), lv);
1123 assert(lv.isSimple());
1124 CGF.EmitStoreOfScalar(null, lv, /* isInitialization */ true);
1127 // There's a potential optimization opportunity in combining
1128 // memsets; that would be easy for arrays, but relatively
1129 // difficult for structures with the current code.
1130 CGF.EmitNullInitialization(lv.getAddress(), lv.getType());
1134 void AggExprEmitter::VisitInitListExpr(InitListExpr *E) {
1136 // FIXME: Assess perf here? Figure out what cases are worth optimizing here
1137 // (Length of globals? Chunks of zeroed-out space?).
1139 // If we can, prefer a copy from a global; this is a lot less code for long
1140 // globals, and it's easier for the current optimizers to analyze.
1141 if (llvm::Constant* C = CGF.CGM.EmitConstantExpr(E, E->getType(), &CGF)) {
1142 llvm::GlobalVariable* GV =
1143 new llvm::GlobalVariable(CGF.CGM.getModule(), C->getType(), true,
1144 llvm::GlobalValue::InternalLinkage, C, "");
1145 EmitFinalDestCopy(E->getType(), CGF.MakeAddrLValue(GV, E->getType()));
1149 if (E->hadArrayRangeDesignator())
1150 CGF.ErrorUnsupported(E, "GNU array range designator extension");
1152 if (E->isTransparent())
1153 return Visit(E->getInit(0));
1155 AggValueSlot Dest = EnsureSlot(E->getType());
1157 LValue DestLV = CGF.MakeAddrLValue(Dest.getAddress(), E->getType());
1159 // Handle initialization of an array.
1160 if (E->getType()->isArrayType()) {
1161 QualType elementType =
1162 CGF.getContext().getAsArrayType(E->getType())->getElementType();
1164 auto AType = cast<llvm::ArrayType>(Dest.getAddress().getElementType());
1165 EmitArrayInit(Dest.getAddress(), AType, elementType, E);
1169 assert(E->getType()->isRecordType() && "Only support structs/unions here!");
1171 // Do struct initialization; this code just sets each individual member
1172 // to the approprate value. This makes bitfield support automatic;
1173 // the disadvantage is that the generated code is more difficult for
1174 // the optimizer, especially with bitfields.
1175 unsigned NumInitElements = E->getNumInits();
1176 RecordDecl *record = E->getType()->castAs<RecordType>()->getDecl();
1178 // We'll need to enter cleanup scopes in case any of the element
1179 // initializers throws an exception.
1180 SmallVector<EHScopeStack::stable_iterator, 16> cleanups;
1181 llvm::Instruction *cleanupDominator = nullptr;
1183 unsigned curInitIndex = 0;
1185 // Emit initialization of base classes.
1186 if (auto *CXXRD = dyn_cast<CXXRecordDecl>(record)) {
1187 assert(E->getNumInits() >= CXXRD->getNumBases() &&
1188 "missing initializer for base class");
1189 for (auto &Base : CXXRD->bases()) {
1190 assert(!Base.isVirtual() && "should not see vbases here");
1191 auto *BaseRD = Base.getType()->getAsCXXRecordDecl();
1192 Address V = CGF.GetAddressOfDirectBaseInCompleteClass(
1193 Dest.getAddress(), CXXRD, BaseRD,
1194 /*isBaseVirtual*/ false);
1195 AggValueSlot AggSlot =
1196 AggValueSlot::forAddr(V, Qualifiers(),
1197 AggValueSlot::IsDestructed,
1198 AggValueSlot::DoesNotNeedGCBarriers,
1199 AggValueSlot::IsNotAliased);
1200 CGF.EmitAggExpr(E->getInit(curInitIndex++), AggSlot);
1202 if (QualType::DestructionKind dtorKind =
1203 Base.getType().isDestructedType()) {
1204 CGF.pushDestroy(dtorKind, V, Base.getType());
1205 cleanups.push_back(CGF.EHStack.stable_begin());
1210 // Prepare a 'this' for CXXDefaultInitExprs.
1211 CodeGenFunction::FieldConstructionScope FCS(CGF, Dest.getAddress());
1213 if (record->isUnion()) {
1214 // Only initialize one field of a union. The field itself is
1215 // specified by the initializer list.
1216 if (!E->getInitializedFieldInUnion()) {
1217 // Empty union; we have nothing to do.
1220 // Make sure that it's really an empty and not a failure of
1221 // semantic analysis.
1222 for (const auto *Field : record->fields())
1223 assert(Field->isUnnamedBitfield() && "Only unnamed bitfields allowed");
1228 // FIXME: volatility
1229 FieldDecl *Field = E->getInitializedFieldInUnion();
1231 LValue FieldLoc = CGF.EmitLValueForFieldInitialization(DestLV, Field);
1232 if (NumInitElements) {
1233 // Store the initializer into the field
1234 EmitInitializationToLValue(E->getInit(0), FieldLoc);
1236 // Default-initialize to null.
1237 EmitNullInitializationToLValue(FieldLoc);
1243 // Here we iterate over the fields; this makes it simpler to both
1244 // default-initialize fields and skip over unnamed fields.
1245 for (const auto *field : record->fields()) {
1246 // We're done once we hit the flexible array member.
1247 if (field->getType()->isIncompleteArrayType())
1250 // Always skip anonymous bitfields.
1251 if (field->isUnnamedBitfield())
1254 // We're done if we reach the end of the explicit initializers, we
1255 // have a zeroed object, and the rest of the fields are
1256 // zero-initializable.
1257 if (curInitIndex == NumInitElements && Dest.isZeroed() &&
1258 CGF.getTypes().isZeroInitializable(E->getType()))
1262 LValue LV = CGF.EmitLValueForFieldInitialization(DestLV, field);
1263 // We never generate write-barries for initialized fields.
1266 if (curInitIndex < NumInitElements) {
1267 // Store the initializer into the field.
1268 EmitInitializationToLValue(E->getInit(curInitIndex++), LV);
1270 // We're out of initalizers; default-initialize to null
1271 EmitNullInitializationToLValue(LV);
1274 // Push a destructor if necessary.
1275 // FIXME: if we have an array of structures, all explicitly
1276 // initialized, we can end up pushing a linear number of cleanups.
1277 bool pushedCleanup = false;
1278 if (QualType::DestructionKind dtorKind
1279 = field->getType().isDestructedType()) {
1280 assert(LV.isSimple());
1281 if (CGF.needsEHCleanup(dtorKind)) {
1282 if (!cleanupDominator)
1283 cleanupDominator = CGF.Builder.CreateAlignedLoad(
1285 llvm::Constant::getNullValue(CGF.Int8PtrTy),
1286 CharUnits::One()); // placeholder
1288 CGF.pushDestroy(EHCleanup, LV.getAddress(), field->getType(),
1289 CGF.getDestroyer(dtorKind), false);
1290 cleanups.push_back(CGF.EHStack.stable_begin());
1291 pushedCleanup = true;
1295 // If the GEP didn't get used because of a dead zero init or something
1296 // else, clean it up for -O0 builds and general tidiness.
1297 if (!pushedCleanup && LV.isSimple())
1298 if (llvm::GetElementPtrInst *GEP =
1299 dyn_cast<llvm::GetElementPtrInst>(LV.getPointer()))
1300 if (GEP->use_empty())
1301 GEP->eraseFromParent();
1304 // Deactivate all the partial cleanups in reverse order, which
1305 // generally means popping them.
1306 for (unsigned i = cleanups.size(); i != 0; --i)
1307 CGF.DeactivateCleanupBlock(cleanups[i-1], cleanupDominator);
1309 // Destroy the placeholder if we made one.
1310 if (cleanupDominator)
1311 cleanupDominator->eraseFromParent();
1314 void AggExprEmitter::VisitArrayInitLoopExpr(const ArrayInitLoopExpr *E,
1315 llvm::Value *outerBegin) {
1316 // Emit the common subexpression.
1317 CodeGenFunction::OpaqueValueMapping binding(CGF, E->getCommonExpr());
1319 Address destPtr = EnsureSlot(E->getType()).getAddress();
1320 uint64_t numElements = E->getArraySize().getZExtValue();
1325 // destPtr is an array*. Construct an elementType* by drilling down a level.
1326 llvm::Value *zero = llvm::ConstantInt::get(CGF.SizeTy, 0);
1327 llvm::Value *indices[] = {zero, zero};
1328 llvm::Value *begin = Builder.CreateInBoundsGEP(destPtr.getPointer(), indices,
1331 // Prepare to special-case multidimensional array initialization: we avoid
1332 // emitting multiple destructor loops in that case.
1335 ArrayInitLoopExpr *InnerLoop = dyn_cast<ArrayInitLoopExpr>(E->getSubExpr());
1337 QualType elementType =
1338 CGF.getContext().getAsArrayType(E->getType())->getElementType();
1339 CharUnits elementSize = CGF.getContext().getTypeSizeInChars(elementType);
1340 CharUnits elementAlign =
1341 destPtr.getAlignment().alignmentOfArrayElement(elementSize);
1343 llvm::BasicBlock *entryBB = Builder.GetInsertBlock();
1344 llvm::BasicBlock *bodyBB = CGF.createBasicBlock("arrayinit.body");
1346 // Jump into the body.
1347 CGF.EmitBlock(bodyBB);
1348 llvm::PHINode *index =
1349 Builder.CreatePHI(zero->getType(), 2, "arrayinit.index");
1350 index->addIncoming(zero, entryBB);
1351 llvm::Value *element = Builder.CreateInBoundsGEP(begin, index);
1353 // Prepare for a cleanup.
1354 QualType::DestructionKind dtorKind = elementType.isDestructedType();
1355 EHScopeStack::stable_iterator cleanup;
1356 if (CGF.needsEHCleanup(dtorKind) && !InnerLoop) {
1357 if (outerBegin->getType() != element->getType())
1358 outerBegin = Builder.CreateBitCast(outerBegin, element->getType());
1359 CGF.pushRegularPartialArrayCleanup(outerBegin, element, elementType,
1361 CGF.getDestroyer(dtorKind));
1362 cleanup = CGF.EHStack.stable_begin();
1364 dtorKind = QualType::DK_none;
1367 // Emit the actual filler expression.
1369 // Temporaries created in an array initialization loop are destroyed
1370 // at the end of each iteration.
1371 CodeGenFunction::RunCleanupsScope CleanupsScope(CGF);
1372 CodeGenFunction::ArrayInitLoopExprScope Scope(CGF, index);
1374 CGF.MakeAddrLValue(Address(element, elementAlign), elementType);
1377 // If the subexpression is an ArrayInitLoopExpr, share its cleanup.
1378 auto elementSlot = AggValueSlot::forLValue(
1379 elementLV, AggValueSlot::IsDestructed,
1380 AggValueSlot::DoesNotNeedGCBarriers, AggValueSlot::IsNotAliased);
1381 AggExprEmitter(CGF, elementSlot, false)
1382 .VisitArrayInitLoopExpr(InnerLoop, outerBegin);
1384 EmitInitializationToLValue(E->getSubExpr(), elementLV);
1387 // Move on to the next element.
1388 llvm::Value *nextIndex = Builder.CreateNUWAdd(
1389 index, llvm::ConstantInt::get(CGF.SizeTy, 1), "arrayinit.next");
1390 index->addIncoming(nextIndex, Builder.GetInsertBlock());
1392 // Leave the loop if we're done.
1393 llvm::Value *done = Builder.CreateICmpEQ(
1394 nextIndex, llvm::ConstantInt::get(CGF.SizeTy, numElements),
1396 llvm::BasicBlock *endBB = CGF.createBasicBlock("arrayinit.end");
1397 Builder.CreateCondBr(done, endBB, bodyBB);
1399 CGF.EmitBlock(endBB);
1401 // Leave the partial-array cleanup if we entered one.
1403 CGF.DeactivateCleanupBlock(cleanup, index);
1406 void AggExprEmitter::VisitDesignatedInitUpdateExpr(DesignatedInitUpdateExpr *E) {
1407 AggValueSlot Dest = EnsureSlot(E->getType());
1409 LValue DestLV = CGF.MakeAddrLValue(Dest.getAddress(), E->getType());
1410 EmitInitializationToLValue(E->getBase(), DestLV);
1411 VisitInitListExpr(E->getUpdater());
1414 //===----------------------------------------------------------------------===//
1415 // Entry Points into this File
1416 //===----------------------------------------------------------------------===//
1418 /// GetNumNonZeroBytesInInit - Get an approximate count of the number of
1419 /// non-zero bytes that will be stored when outputting the initializer for the
1420 /// specified initializer expression.
1421 static CharUnits GetNumNonZeroBytesInInit(const Expr *E, CodeGenFunction &CGF) {
1422 E = E->IgnoreParens();
1424 // 0 and 0.0 won't require any non-zero stores!
1425 if (isSimpleZero(E, CGF)) return CharUnits::Zero();
1427 // If this is an initlist expr, sum up the size of sizes of the (present)
1428 // elements. If this is something weird, assume the whole thing is non-zero.
1429 const InitListExpr *ILE = dyn_cast<InitListExpr>(E);
1430 if (!ILE || !CGF.getTypes().isZeroInitializable(ILE->getType()))
1431 return CGF.getContext().getTypeSizeInChars(E->getType());
1433 // InitListExprs for structs have to be handled carefully. If there are
1434 // reference members, we need to consider the size of the reference, not the
1435 // referencee. InitListExprs for unions and arrays can't have references.
1436 if (const RecordType *RT = E->getType()->getAs<RecordType>()) {
1437 if (!RT->isUnionType()) {
1438 RecordDecl *SD = E->getType()->getAs<RecordType>()->getDecl();
1439 CharUnits NumNonZeroBytes = CharUnits::Zero();
1441 unsigned ILEElement = 0;
1442 if (auto *CXXRD = dyn_cast<CXXRecordDecl>(SD))
1443 while (ILEElement != CXXRD->getNumBases())
1445 GetNumNonZeroBytesInInit(ILE->getInit(ILEElement++), CGF);
1446 for (const auto *Field : SD->fields()) {
1447 // We're done once we hit the flexible array member or run out of
1448 // InitListExpr elements.
1449 if (Field->getType()->isIncompleteArrayType() ||
1450 ILEElement == ILE->getNumInits())
1452 if (Field->isUnnamedBitfield())
1455 const Expr *E = ILE->getInit(ILEElement++);
1457 // Reference values are always non-null and have the width of a pointer.
1458 if (Field->getType()->isReferenceType())
1459 NumNonZeroBytes += CGF.getContext().toCharUnitsFromBits(
1460 CGF.getTarget().getPointerWidth(0));
1462 NumNonZeroBytes += GetNumNonZeroBytesInInit(E, CGF);
1465 return NumNonZeroBytes;
1470 CharUnits NumNonZeroBytes = CharUnits::Zero();
1471 for (unsigned i = 0, e = ILE->getNumInits(); i != e; ++i)
1472 NumNonZeroBytes += GetNumNonZeroBytesInInit(ILE->getInit(i), CGF);
1473 return NumNonZeroBytes;
1476 /// CheckAggExprForMemSetUse - If the initializer is large and has a lot of
1477 /// zeros in it, emit a memset and avoid storing the individual zeros.
1479 static void CheckAggExprForMemSetUse(AggValueSlot &Slot, const Expr *E,
1480 CodeGenFunction &CGF) {
1481 // If the slot is already known to be zeroed, nothing to do. Don't mess with
1483 if (Slot.isZeroed() || Slot.isVolatile() || !Slot.getAddress().isValid())
1486 // C++ objects with a user-declared constructor don't need zero'ing.
1487 if (CGF.getLangOpts().CPlusPlus)
1488 if (const RecordType *RT = CGF.getContext()
1489 .getBaseElementType(E->getType())->getAs<RecordType>()) {
1490 const CXXRecordDecl *RD = cast<CXXRecordDecl>(RT->getDecl());
1491 if (RD->hasUserDeclaredConstructor())
1495 // If the type is 16-bytes or smaller, prefer individual stores over memset.
1496 CharUnits Size = CGF.getContext().getTypeSizeInChars(E->getType());
1497 if (Size <= CharUnits::fromQuantity(16))
1500 // Check to see if over 3/4 of the initializer are known to be zero. If so,
1501 // we prefer to emit memset + individual stores for the rest.
1502 CharUnits NumNonZeroBytes = GetNumNonZeroBytesInInit(E, CGF);
1503 if (NumNonZeroBytes*4 > Size)
1506 // Okay, it seems like a good idea to use an initial memset, emit the call.
1507 llvm::Constant *SizeVal = CGF.Builder.getInt64(Size.getQuantity());
1509 Address Loc = Slot.getAddress();
1510 Loc = CGF.Builder.CreateElementBitCast(Loc, CGF.Int8Ty);
1511 CGF.Builder.CreateMemSet(Loc, CGF.Builder.getInt8(0), SizeVal, false);
1513 // Tell the AggExprEmitter that the slot is known zero.
1520 /// EmitAggExpr - Emit the computation of the specified expression of aggregate
1521 /// type. The result is computed into DestPtr. Note that if DestPtr is null,
1522 /// the value of the aggregate expression is not needed. If VolatileDest is
1523 /// true, DestPtr cannot be 0.
1524 void CodeGenFunction::EmitAggExpr(const Expr *E, AggValueSlot Slot) {
1525 assert(E && hasAggregateEvaluationKind(E->getType()) &&
1526 "Invalid aggregate expression to emit");
1527 assert((Slot.getAddress().isValid() || Slot.isIgnored()) &&
1528 "slot has bits but no address");
1530 // Optimize the slot if possible.
1531 CheckAggExprForMemSetUse(Slot, E, *this);
1533 AggExprEmitter(*this, Slot, Slot.isIgnored()).Visit(const_cast<Expr*>(E));
1536 LValue CodeGenFunction::EmitAggExprToLValue(const Expr *E) {
1537 assert(hasAggregateEvaluationKind(E->getType()) && "Invalid argument!");
1538 Address Temp = CreateMemTemp(E->getType());
1539 LValue LV = MakeAddrLValue(Temp, E->getType());
1540 EmitAggExpr(E, AggValueSlot::forLValue(LV, AggValueSlot::IsNotDestructed,
1541 AggValueSlot::DoesNotNeedGCBarriers,
1542 AggValueSlot::IsNotAliased));
1546 void CodeGenFunction::EmitAggregateCopy(Address DestPtr,
1547 Address SrcPtr, QualType Ty,
1549 bool isAssignment) {
1550 assert(!Ty->isAnyComplexType() && "Shouldn't happen for complex");
1552 if (getLangOpts().CPlusPlus) {
1553 if (const RecordType *RT = Ty->getAs<RecordType>()) {
1554 CXXRecordDecl *Record = cast<CXXRecordDecl>(RT->getDecl());
1555 assert((Record->hasTrivialCopyConstructor() ||
1556 Record->hasTrivialCopyAssignment() ||
1557 Record->hasTrivialMoveConstructor() ||
1558 Record->hasTrivialMoveAssignment() ||
1559 Record->isUnion()) &&
1560 "Trying to aggregate-copy a type without a trivial copy/move "
1561 "constructor or assignment operator");
1562 // Ignore empty classes in C++.
1563 if (Record->isEmpty())
1568 // Aggregate assignment turns into llvm.memcpy. This is almost valid per
1569 // C99 6.5.16.1p3, which states "If the value being stored in an object is
1570 // read from another object that overlaps in anyway the storage of the first
1571 // object, then the overlap shall be exact and the two objects shall have
1572 // qualified or unqualified versions of a compatible type."
1574 // memcpy is not defined if the source and destination pointers are exactly
1575 // equal, but other compilers do this optimization, and almost every memcpy
1576 // implementation handles this case safely. If there is a libc that does not
1577 // safely handle this, we can add a target hook.
1579 // Get data size info for this aggregate. If this is an assignment,
1580 // don't copy the tail padding, because we might be assigning into a
1581 // base subobject where the tail padding is claimed. Otherwise,
1582 // copying it is fine.
1583 std::pair<CharUnits, CharUnits> TypeInfo;
1585 TypeInfo = getContext().getTypeInfoDataSizeInChars(Ty);
1587 TypeInfo = getContext().getTypeInfoInChars(Ty);
1589 llvm::Value *SizeVal = nullptr;
1590 if (TypeInfo.first.isZero()) {
1591 // But note that getTypeInfo returns 0 for a VLA.
1592 if (auto *VAT = dyn_cast_or_null<VariableArrayType>(
1593 getContext().getAsArrayType(Ty))) {
1595 SizeVal = emitArrayLength(VAT, BaseEltTy, DestPtr);
1596 TypeInfo = getContext().getTypeInfoDataSizeInChars(BaseEltTy);
1597 std::pair<CharUnits, CharUnits> LastElementTypeInfo;
1599 LastElementTypeInfo = getContext().getTypeInfoInChars(BaseEltTy);
1600 assert(!TypeInfo.first.isZero());
1601 SizeVal = Builder.CreateNUWMul(
1603 llvm::ConstantInt::get(SizeTy, TypeInfo.first.getQuantity()));
1604 if (!isAssignment) {
1605 SizeVal = Builder.CreateNUWSub(
1607 llvm::ConstantInt::get(SizeTy, TypeInfo.first.getQuantity()));
1608 SizeVal = Builder.CreateNUWAdd(
1609 SizeVal, llvm::ConstantInt::get(
1610 SizeTy, LastElementTypeInfo.first.getQuantity()));
1615 SizeVal = llvm::ConstantInt::get(SizeTy, TypeInfo.first.getQuantity());
1618 // FIXME: If we have a volatile struct, the optimizer can remove what might
1619 // appear to be `extra' memory ops:
1621 // volatile struct { int i; } a, b;
1628 // we need to use a different call here. We use isVolatile to indicate when
1629 // either the source or the destination is volatile.
1631 DestPtr = Builder.CreateElementBitCast(DestPtr, Int8Ty);
1632 SrcPtr = Builder.CreateElementBitCast(SrcPtr, Int8Ty);
1634 // Don't do any of the memmove_collectable tests if GC isn't set.
1635 if (CGM.getLangOpts().getGC() == LangOptions::NonGC) {
1637 } else if (const RecordType *RecordTy = Ty->getAs<RecordType>()) {
1638 RecordDecl *Record = RecordTy->getDecl();
1639 if (Record->hasObjectMember()) {
1640 CGM.getObjCRuntime().EmitGCMemmoveCollectable(*this, DestPtr, SrcPtr,
1644 } else if (Ty->isArrayType()) {
1645 QualType BaseType = getContext().getBaseElementType(Ty);
1646 if (const RecordType *RecordTy = BaseType->getAs<RecordType>()) {
1647 if (RecordTy->getDecl()->hasObjectMember()) {
1648 CGM.getObjCRuntime().EmitGCMemmoveCollectable(*this, DestPtr, SrcPtr,
1655 auto Inst = Builder.CreateMemCpy(DestPtr, SrcPtr, SizeVal, isVolatile);
1657 // Determine the metadata to describe the position of any padding in this
1658 // memcpy, as well as the TBAA tags for the members of the struct, in case
1659 // the optimizer wishes to expand it in to scalar memory operations.
1660 if (llvm::MDNode *TBAAStructTag = CGM.getTBAAStructInfo(Ty))
1661 Inst->setMetadata(llvm::LLVMContext::MD_tbaa_struct, TBAAStructTag);