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"
16 #include "CGObjCRuntime.h"
17 #include "CodeGenModule.h"
18 #include "ConstantEmitter.h"
19 #include "clang/AST/ASTContext.h"
20 #include "clang/AST/DeclCXX.h"
21 #include "clang/AST/DeclTemplate.h"
22 #include "clang/AST/StmtVisitor.h"
23 #include "llvm/IR/Constants.h"
24 #include "llvm/IR/Function.h"
25 #include "llvm/IR/GlobalVariable.h"
26 #include "llvm/IR/Intrinsics.h"
27 #include "llvm/IR/IntrinsicInst.h"
28 using namespace clang;
29 using namespace CodeGen;
31 //===----------------------------------------------------------------------===//
32 // Aggregate Expression Emitter
33 //===----------------------------------------------------------------------===//
36 class AggExprEmitter : public StmtVisitor<AggExprEmitter> {
42 AggValueSlot EnsureSlot(QualType T) {
43 if (!Dest.isIgnored()) return Dest;
44 return CGF.CreateAggTemp(T, "agg.tmp.ensured");
46 void EnsureDest(QualType T) {
47 if (!Dest.isIgnored()) return;
48 Dest = CGF.CreateAggTemp(T, "agg.tmp.ensured");
51 // Calls `Fn` with a valid return value slot, potentially creating a temporary
52 // to do so. If a temporary is created, an appropriate copy into `Dest` will
53 // be emitted, as will lifetime markers.
55 // The given function should take a ReturnValueSlot, and return an RValue that
56 // points to said slot.
57 void withReturnValueSlot(const Expr *E,
58 llvm::function_ref<RValue(ReturnValueSlot)> Fn);
61 AggExprEmitter(CodeGenFunction &cgf, AggValueSlot Dest, bool IsResultUnused)
62 : CGF(cgf), Builder(CGF.Builder), Dest(Dest),
63 IsResultUnused(IsResultUnused) { }
65 //===--------------------------------------------------------------------===//
67 //===--------------------------------------------------------------------===//
69 /// EmitAggLoadOfLValue - Given an expression with aggregate type that
70 /// represents a value lvalue, this method emits the address of the lvalue,
71 /// then loads the result into DestPtr.
72 void EmitAggLoadOfLValue(const Expr *E);
79 /// EmitFinalDestCopy - Perform the final copy to DestPtr, if desired.
80 /// SrcIsRValue is true if source comes from an RValue.
81 void EmitFinalDestCopy(QualType type, const LValue &src,
82 ExprValueKind SrcValueKind = EVK_NonRValue);
83 void EmitFinalDestCopy(QualType type, RValue src);
84 void EmitCopy(QualType type, const AggValueSlot &dest,
85 const AggValueSlot &src);
87 void EmitMoveFromReturnSlot(const Expr *E, RValue Src);
89 void EmitArrayInit(Address DestPtr, llvm::ArrayType *AType,
90 QualType ArrayQTy, InitListExpr *E);
92 AggValueSlot::NeedsGCBarriers_t needsGC(QualType T) {
93 if (CGF.getLangOpts().getGC() && TypeRequiresGCollection(T))
94 return AggValueSlot::NeedsGCBarriers;
95 return AggValueSlot::DoesNotNeedGCBarriers;
98 bool TypeRequiresGCollection(QualType T);
100 //===--------------------------------------------------------------------===//
102 //===--------------------------------------------------------------------===//
104 void Visit(Expr *E) {
105 ApplyDebugLocation DL(CGF, E);
106 StmtVisitor<AggExprEmitter>::Visit(E);
109 void VisitStmt(Stmt *S) {
110 CGF.ErrorUnsupported(S, "aggregate expression");
112 void VisitParenExpr(ParenExpr *PE) { Visit(PE->getSubExpr()); }
113 void VisitGenericSelectionExpr(GenericSelectionExpr *GE) {
114 Visit(GE->getResultExpr());
116 void VisitCoawaitExpr(CoawaitExpr *E) {
117 CGF.EmitCoawaitExpr(*E, Dest, IsResultUnused);
119 void VisitCoyieldExpr(CoyieldExpr *E) {
120 CGF.EmitCoyieldExpr(*E, Dest, IsResultUnused);
122 void VisitUnaryCoawait(UnaryOperator *E) { Visit(E->getSubExpr()); }
123 void VisitUnaryExtension(UnaryOperator *E) { Visit(E->getSubExpr()); }
124 void VisitSubstNonTypeTemplateParmExpr(SubstNonTypeTemplateParmExpr *E) {
125 return Visit(E->getReplacement());
129 void VisitDeclRefExpr(DeclRefExpr *E) { EmitAggLoadOfLValue(E); }
130 void VisitMemberExpr(MemberExpr *ME) { EmitAggLoadOfLValue(ME); }
131 void VisitUnaryDeref(UnaryOperator *E) { EmitAggLoadOfLValue(E); }
132 void VisitStringLiteral(StringLiteral *E) { EmitAggLoadOfLValue(E); }
133 void VisitCompoundLiteralExpr(CompoundLiteralExpr *E);
134 void VisitArraySubscriptExpr(ArraySubscriptExpr *E) {
135 EmitAggLoadOfLValue(E);
137 void VisitPredefinedExpr(const PredefinedExpr *E) {
138 EmitAggLoadOfLValue(E);
142 void VisitCastExpr(CastExpr *E);
143 void VisitCallExpr(const CallExpr *E);
144 void VisitStmtExpr(const StmtExpr *E);
145 void VisitBinaryOperator(const BinaryOperator *BO);
146 void VisitPointerToDataMemberBinaryOperator(const BinaryOperator *BO);
147 void VisitBinAssign(const BinaryOperator *E);
148 void VisitBinComma(const BinaryOperator *E);
149 void VisitBinCmp(const BinaryOperator *E);
151 void VisitObjCMessageExpr(ObjCMessageExpr *E);
152 void VisitObjCIvarRefExpr(ObjCIvarRefExpr *E) {
153 EmitAggLoadOfLValue(E);
156 void VisitDesignatedInitUpdateExpr(DesignatedInitUpdateExpr *E);
157 void VisitAbstractConditionalOperator(const AbstractConditionalOperator *CO);
158 void VisitChooseExpr(const ChooseExpr *CE);
159 void VisitInitListExpr(InitListExpr *E);
160 void VisitArrayInitLoopExpr(const ArrayInitLoopExpr *E,
161 llvm::Value *outerBegin = nullptr);
162 void VisitImplicitValueInitExpr(ImplicitValueInitExpr *E);
163 void VisitNoInitExpr(NoInitExpr *E) { } // Do nothing.
164 void VisitCXXDefaultArgExpr(CXXDefaultArgExpr *DAE) {
165 Visit(DAE->getExpr());
167 void VisitCXXDefaultInitExpr(CXXDefaultInitExpr *DIE) {
168 CodeGenFunction::CXXDefaultInitExprScope Scope(CGF);
169 Visit(DIE->getExpr());
171 void VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E);
172 void VisitCXXConstructExpr(const CXXConstructExpr *E);
173 void VisitCXXInheritedCtorInitExpr(const CXXInheritedCtorInitExpr *E);
174 void VisitLambdaExpr(LambdaExpr *E);
175 void VisitCXXStdInitializerListExpr(CXXStdInitializerListExpr *E);
176 void VisitExprWithCleanups(ExprWithCleanups *E);
177 void VisitCXXScalarValueInitExpr(CXXScalarValueInitExpr *E);
178 void VisitCXXTypeidExpr(CXXTypeidExpr *E) { EmitAggLoadOfLValue(E); }
179 void VisitMaterializeTemporaryExpr(MaterializeTemporaryExpr *E);
180 void VisitOpaqueValueExpr(OpaqueValueExpr *E);
182 void VisitPseudoObjectExpr(PseudoObjectExpr *E) {
183 if (E->isGLValue()) {
184 LValue LV = CGF.EmitPseudoObjectLValue(E);
185 return EmitFinalDestCopy(E->getType(), LV);
188 CGF.EmitPseudoObjectRValue(E, EnsureSlot(E->getType()));
191 void VisitVAArgExpr(VAArgExpr *E);
193 void EmitInitializationToLValue(Expr *E, LValue Address);
194 void EmitNullInitializationToLValue(LValue Address);
195 // case Expr::ChooseExprClass:
196 void VisitCXXThrowExpr(const CXXThrowExpr *E) { CGF.EmitCXXThrowExpr(E); }
197 void VisitAtomicExpr(AtomicExpr *E) {
198 RValue Res = CGF.EmitAtomicExpr(E);
199 EmitFinalDestCopy(E->getType(), Res);
202 } // end anonymous namespace.
204 //===----------------------------------------------------------------------===//
206 //===----------------------------------------------------------------------===//
208 /// EmitAggLoadOfLValue - Given an expression with aggregate type that
209 /// represents a value lvalue, this method emits the address of the lvalue,
210 /// then loads the result into DestPtr.
211 void AggExprEmitter::EmitAggLoadOfLValue(const Expr *E) {
212 LValue LV = CGF.EmitLValue(E);
214 // If the type of the l-value is atomic, then do an atomic load.
215 if (LV.getType()->isAtomicType() || CGF.LValueIsSuitableForInlineAtomic(LV)) {
216 CGF.EmitAtomicLoad(LV, E->getExprLoc(), Dest);
220 EmitFinalDestCopy(E->getType(), LV);
223 /// True if the given aggregate type requires special GC API calls.
224 bool AggExprEmitter::TypeRequiresGCollection(QualType T) {
225 // Only record types have members that might require garbage collection.
226 const RecordType *RecordTy = T->getAs<RecordType>();
227 if (!RecordTy) return false;
229 // Don't mess with non-trivial C++ types.
230 RecordDecl *Record = RecordTy->getDecl();
231 if (isa<CXXRecordDecl>(Record) &&
232 (cast<CXXRecordDecl>(Record)->hasNonTrivialCopyConstructor() ||
233 !cast<CXXRecordDecl>(Record)->hasTrivialDestructor()))
236 // Check whether the type has an object member.
237 return Record->hasObjectMember();
240 void AggExprEmitter::withReturnValueSlot(
241 const Expr *E, llvm::function_ref<RValue(ReturnValueSlot)> EmitCall) {
242 QualType RetTy = E->getType();
243 bool RequiresDestruction =
245 RetTy.isDestructedType() == QualType::DK_nontrivial_c_struct;
247 // If it makes no observable difference, save a memcpy + temporary.
249 // We need to always provide our own temporary if destruction is required.
250 // Otherwise, EmitCall will emit its own, notice that it's "unused", and end
251 // its lifetime before we have the chance to emit a proper destructor call.
252 bool UseTemp = Dest.isPotentiallyAliased() || Dest.requiresGCollection() ||
253 (RequiresDestruction && !Dest.getAddress().isValid());
255 Address RetAddr = Address::invalid();
256 Address RetAllocaAddr = Address::invalid();
258 EHScopeStack::stable_iterator LifetimeEndBlock;
259 llvm::Value *LifetimeSizePtr = nullptr;
260 llvm::IntrinsicInst *LifetimeStartInst = nullptr;
262 RetAddr = Dest.getAddress();
264 RetAddr = CGF.CreateMemTemp(RetTy, "tmp", &RetAllocaAddr);
266 CGF.CGM.getDataLayout().getTypeAllocSize(CGF.ConvertTypeForMem(RetTy));
267 LifetimeSizePtr = CGF.EmitLifetimeStart(Size, RetAllocaAddr.getPointer());
268 if (LifetimeSizePtr) {
270 cast<llvm::IntrinsicInst>(std::prev(Builder.GetInsertPoint()));
271 assert(LifetimeStartInst->getIntrinsicID() ==
272 llvm::Intrinsic::lifetime_start &&
273 "Last insertion wasn't a lifetime.start?");
275 CGF.pushFullExprCleanup<CodeGenFunction::CallLifetimeEnd>(
276 NormalEHLifetimeMarker, RetAllocaAddr, LifetimeSizePtr);
277 LifetimeEndBlock = CGF.EHStack.stable_begin();
282 EmitCall(ReturnValueSlot(RetAddr, Dest.isVolatile(), IsResultUnused));
284 if (RequiresDestruction)
285 CGF.pushDestroy(RetTy.isDestructedType(), Src.getAggregateAddress(), RetTy);
290 assert(Dest.getPointer() != Src.getAggregatePointer());
291 EmitFinalDestCopy(E->getType(), Src);
293 if (!RequiresDestruction && LifetimeStartInst) {
294 // If there's no dtor to run, the copy was the last use of our temporary.
295 // Since we're not guaranteed to be in an ExprWithCleanups, clean up
297 CGF.DeactivateCleanupBlock(LifetimeEndBlock, LifetimeStartInst);
298 CGF.EmitLifetimeEnd(LifetimeSizePtr, RetAllocaAddr.getPointer());
302 /// EmitFinalDestCopy - Perform the final copy to DestPtr, if desired.
303 void AggExprEmitter::EmitFinalDestCopy(QualType type, RValue src) {
304 assert(src.isAggregate() && "value must be aggregate value!");
305 LValue srcLV = CGF.MakeAddrLValue(src.getAggregateAddress(), type);
306 EmitFinalDestCopy(type, srcLV, EVK_RValue);
309 /// EmitFinalDestCopy - Perform the final copy to DestPtr, if desired.
310 void AggExprEmitter::EmitFinalDestCopy(QualType type, const LValue &src,
311 ExprValueKind SrcValueKind) {
312 // If Dest is ignored, then we're evaluating an aggregate expression
313 // in a context that doesn't care about the result. Note that loads
314 // from volatile l-values force the existence of a non-ignored
316 if (Dest.isIgnored())
319 // Copy non-trivial C structs here.
320 LValue DstLV = CGF.MakeAddrLValue(
321 Dest.getAddress(), Dest.isVolatile() ? type.withVolatile() : type);
323 if (SrcValueKind == EVK_RValue) {
324 if (type.isNonTrivialToPrimitiveDestructiveMove() == QualType::PCK_Struct) {
325 if (Dest.isPotentiallyAliased())
326 CGF.callCStructMoveAssignmentOperator(DstLV, src);
328 CGF.callCStructMoveConstructor(DstLV, src);
332 if (type.isNonTrivialToPrimitiveCopy() == QualType::PCK_Struct) {
333 if (Dest.isPotentiallyAliased())
334 CGF.callCStructCopyAssignmentOperator(DstLV, src);
336 CGF.callCStructCopyConstructor(DstLV, src);
341 AggValueSlot srcAgg =
342 AggValueSlot::forLValue(src, AggValueSlot::IsDestructed,
343 needsGC(type), AggValueSlot::IsAliased,
344 AggValueSlot::MayOverlap);
345 EmitCopy(type, Dest, srcAgg);
348 /// Perform a copy from the source into the destination.
350 /// \param type - the type of the aggregate being copied; qualifiers are
352 void AggExprEmitter::EmitCopy(QualType type, const AggValueSlot &dest,
353 const AggValueSlot &src) {
354 if (dest.requiresGCollection()) {
355 CharUnits sz = dest.getPreferredSize(CGF.getContext(), type);
356 llvm::Value *size = llvm::ConstantInt::get(CGF.SizeTy, sz.getQuantity());
357 CGF.CGM.getObjCRuntime().EmitGCMemmoveCollectable(CGF,
364 // If the result of the assignment is used, copy the LHS there also.
365 // It's volatile if either side is. Use the minimum alignment of
367 LValue DestLV = CGF.MakeAddrLValue(dest.getAddress(), type);
368 LValue SrcLV = CGF.MakeAddrLValue(src.getAddress(), type);
369 CGF.EmitAggregateCopy(DestLV, SrcLV, type, dest.mayOverlap(),
370 dest.isVolatile() || src.isVolatile());
373 /// Emit the initializer for a std::initializer_list initialized with a
374 /// real initializer list.
376 AggExprEmitter::VisitCXXStdInitializerListExpr(CXXStdInitializerListExpr *E) {
377 // Emit an array containing the elements. The array is externally destructed
378 // if the std::initializer_list object is.
379 ASTContext &Ctx = CGF.getContext();
380 LValue Array = CGF.EmitLValue(E->getSubExpr());
381 assert(Array.isSimple() && "initializer_list array not a simple lvalue");
382 Address ArrayPtr = Array.getAddress();
384 const ConstantArrayType *ArrayType =
385 Ctx.getAsConstantArrayType(E->getSubExpr()->getType());
386 assert(ArrayType && "std::initializer_list constructed from non-array");
388 // FIXME: Perform the checks on the field types in SemaInit.
389 RecordDecl *Record = E->getType()->castAs<RecordType>()->getDecl();
390 RecordDecl::field_iterator Field = Record->field_begin();
391 if (Field == Record->field_end()) {
392 CGF.ErrorUnsupported(E, "weird std::initializer_list");
397 if (!Field->getType()->isPointerType() ||
398 !Ctx.hasSameType(Field->getType()->getPointeeType(),
399 ArrayType->getElementType())) {
400 CGF.ErrorUnsupported(E, "weird std::initializer_list");
404 AggValueSlot Dest = EnsureSlot(E->getType());
405 LValue DestLV = CGF.MakeAddrLValue(Dest.getAddress(), E->getType());
406 LValue Start = CGF.EmitLValueForFieldInitialization(DestLV, *Field);
407 llvm::Value *Zero = llvm::ConstantInt::get(CGF.PtrDiffTy, 0);
408 llvm::Value *IdxStart[] = { Zero, Zero };
409 llvm::Value *ArrayStart =
410 Builder.CreateInBoundsGEP(ArrayPtr.getPointer(), IdxStart, "arraystart");
411 CGF.EmitStoreThroughLValue(RValue::get(ArrayStart), Start);
414 if (Field == Record->field_end()) {
415 CGF.ErrorUnsupported(E, "weird std::initializer_list");
419 llvm::Value *Size = Builder.getInt(ArrayType->getSize());
420 LValue EndOrLength = CGF.EmitLValueForFieldInitialization(DestLV, *Field);
421 if (Field->getType()->isPointerType() &&
422 Ctx.hasSameType(Field->getType()->getPointeeType(),
423 ArrayType->getElementType())) {
425 llvm::Value *IdxEnd[] = { Zero, Size };
426 llvm::Value *ArrayEnd =
427 Builder.CreateInBoundsGEP(ArrayPtr.getPointer(), IdxEnd, "arrayend");
428 CGF.EmitStoreThroughLValue(RValue::get(ArrayEnd), EndOrLength);
429 } else if (Ctx.hasSameType(Field->getType(), Ctx.getSizeType())) {
431 CGF.EmitStoreThroughLValue(RValue::get(Size), EndOrLength);
433 CGF.ErrorUnsupported(E, "weird std::initializer_list");
438 /// Determine if E is a trivial array filler, that is, one that is
439 /// equivalent to zero-initialization.
440 static bool isTrivialFiller(Expr *E) {
444 if (isa<ImplicitValueInitExpr>(E))
447 if (auto *ILE = dyn_cast<InitListExpr>(E)) {
448 if (ILE->getNumInits())
450 return isTrivialFiller(ILE->getArrayFiller());
453 if (auto *Cons = dyn_cast_or_null<CXXConstructExpr>(E))
454 return Cons->getConstructor()->isDefaultConstructor() &&
455 Cons->getConstructor()->isTrivial();
457 // FIXME: Are there other cases where we can avoid emitting an initializer?
461 /// Emit initialization of an array from an initializer list.
462 void AggExprEmitter::EmitArrayInit(Address DestPtr, llvm::ArrayType *AType,
463 QualType ArrayQTy, InitListExpr *E) {
464 uint64_t NumInitElements = E->getNumInits();
466 uint64_t NumArrayElements = AType->getNumElements();
467 assert(NumInitElements <= NumArrayElements);
469 QualType elementType =
470 CGF.getContext().getAsArrayType(ArrayQTy)->getElementType();
472 // DestPtr is an array*. Construct an elementType* by drilling
474 llvm::Value *zero = llvm::ConstantInt::get(CGF.SizeTy, 0);
475 llvm::Value *indices[] = { zero, zero };
477 Builder.CreateInBoundsGEP(DestPtr.getPointer(), indices, "arrayinit.begin");
479 CharUnits elementSize = CGF.getContext().getTypeSizeInChars(elementType);
480 CharUnits elementAlign =
481 DestPtr.getAlignment().alignmentOfArrayElement(elementSize);
483 // Consider initializing the array by copying from a global. For this to be
484 // more efficient than per-element initialization, the size of the elements
485 // with explicit initializers should be large enough.
486 if (NumInitElements * elementSize.getQuantity() > 16 &&
487 elementType.isTriviallyCopyableType(CGF.getContext())) {
488 CodeGen::CodeGenModule &CGM = CGF.CGM;
489 ConstantEmitter Emitter(CGM);
490 LangAS AS = ArrayQTy.getAddressSpace();
491 if (llvm::Constant *C = Emitter.tryEmitForInitializer(E, AS, ArrayQTy)) {
492 auto GV = new llvm::GlobalVariable(
493 CGM.getModule(), C->getType(),
494 CGM.isTypeConstant(ArrayQTy, /* ExcludeCtorDtor= */ true),
495 llvm::GlobalValue::PrivateLinkage, C, "constinit",
496 /* InsertBefore= */ nullptr, llvm::GlobalVariable::NotThreadLocal,
497 CGM.getContext().getTargetAddressSpace(AS));
498 Emitter.finalize(GV);
499 CharUnits Align = CGM.getContext().getTypeAlignInChars(ArrayQTy);
500 GV->setAlignment(Align.getQuantity());
501 EmitFinalDestCopy(ArrayQTy, CGF.MakeAddrLValue(GV, ArrayQTy, Align));
506 // Exception safety requires us to destroy all the
507 // already-constructed members if an initializer throws.
508 // For that, we'll need an EH cleanup.
509 QualType::DestructionKind dtorKind = elementType.isDestructedType();
510 Address endOfInit = Address::invalid();
511 EHScopeStack::stable_iterator cleanup;
512 llvm::Instruction *cleanupDominator = nullptr;
513 if (CGF.needsEHCleanup(dtorKind)) {
514 // In principle we could tell the cleanup where we are more
515 // directly, but the control flow can get so varied here that it
516 // would actually be quite complex. Therefore we go through an
518 endOfInit = CGF.CreateTempAlloca(begin->getType(), CGF.getPointerAlign(),
519 "arrayinit.endOfInit");
520 cleanupDominator = Builder.CreateStore(begin, endOfInit);
521 CGF.pushIrregularPartialArrayCleanup(begin, endOfInit, elementType,
523 CGF.getDestroyer(dtorKind));
524 cleanup = CGF.EHStack.stable_begin();
526 // Otherwise, remember that we didn't need a cleanup.
528 dtorKind = QualType::DK_none;
531 llvm::Value *one = llvm::ConstantInt::get(CGF.SizeTy, 1);
533 // The 'current element to initialize'. The invariants on this
534 // variable are complicated. Essentially, after each iteration of
535 // the loop, it points to the last initialized element, except
536 // that it points to the beginning of the array before any
537 // elements have been initialized.
538 llvm::Value *element = begin;
540 // Emit the explicit initializers.
541 for (uint64_t i = 0; i != NumInitElements; ++i) {
542 // Advance to the next element.
544 element = Builder.CreateInBoundsGEP(element, one, "arrayinit.element");
546 // Tell the cleanup that it needs to destroy up to this
547 // element. TODO: some of these stores can be trivially
548 // observed to be unnecessary.
549 if (endOfInit.isValid()) Builder.CreateStore(element, endOfInit);
553 CGF.MakeAddrLValue(Address(element, elementAlign), elementType);
554 EmitInitializationToLValue(E->getInit(i), elementLV);
557 // Check whether there's a non-trivial array-fill expression.
558 Expr *filler = E->getArrayFiller();
559 bool hasTrivialFiller = isTrivialFiller(filler);
561 // Any remaining elements need to be zero-initialized, possibly
562 // using the filler expression. We can skip this if the we're
563 // emitting to zeroed memory.
564 if (NumInitElements != NumArrayElements &&
565 !(Dest.isZeroed() && hasTrivialFiller &&
566 CGF.getTypes().isZeroInitializable(elementType))) {
568 // Use an actual loop. This is basically
569 // do { *array++ = filler; } while (array != end);
571 // Advance to the start of the rest of the array.
572 if (NumInitElements) {
573 element = Builder.CreateInBoundsGEP(element, one, "arrayinit.start");
574 if (endOfInit.isValid()) Builder.CreateStore(element, endOfInit);
577 // Compute the end of the array.
578 llvm::Value *end = Builder.CreateInBoundsGEP(begin,
579 llvm::ConstantInt::get(CGF.SizeTy, NumArrayElements),
582 llvm::BasicBlock *entryBB = Builder.GetInsertBlock();
583 llvm::BasicBlock *bodyBB = CGF.createBasicBlock("arrayinit.body");
585 // Jump into the body.
586 CGF.EmitBlock(bodyBB);
587 llvm::PHINode *currentElement =
588 Builder.CreatePHI(element->getType(), 2, "arrayinit.cur");
589 currentElement->addIncoming(element, entryBB);
591 // Emit the actual filler expression.
593 // C++1z [class.temporary]p5:
594 // when a default constructor is called to initialize an element of
595 // an array with no corresponding initializer [...] the destruction of
596 // every temporary created in a default argument is sequenced before
597 // the construction of the next array element, if any
598 CodeGenFunction::RunCleanupsScope CleanupsScope(CGF);
600 CGF.MakeAddrLValue(Address(currentElement, elementAlign), elementType);
602 EmitInitializationToLValue(filler, elementLV);
604 EmitNullInitializationToLValue(elementLV);
607 // Move on to the next element.
608 llvm::Value *nextElement =
609 Builder.CreateInBoundsGEP(currentElement, one, "arrayinit.next");
611 // Tell the EH cleanup that we finished with the last element.
612 if (endOfInit.isValid()) Builder.CreateStore(nextElement, endOfInit);
614 // Leave the loop if we're done.
615 llvm::Value *done = Builder.CreateICmpEQ(nextElement, end,
617 llvm::BasicBlock *endBB = CGF.createBasicBlock("arrayinit.end");
618 Builder.CreateCondBr(done, endBB, bodyBB);
619 currentElement->addIncoming(nextElement, Builder.GetInsertBlock());
621 CGF.EmitBlock(endBB);
624 // Leave the partial-array cleanup if we entered one.
625 if (dtorKind) CGF.DeactivateCleanupBlock(cleanup, cleanupDominator);
628 //===----------------------------------------------------------------------===//
630 //===----------------------------------------------------------------------===//
632 void AggExprEmitter::VisitMaterializeTemporaryExpr(MaterializeTemporaryExpr *E){
633 Visit(E->GetTemporaryExpr());
636 void AggExprEmitter::VisitOpaqueValueExpr(OpaqueValueExpr *e) {
637 // If this is a unique OVE, just visit its source expression.
639 Visit(e->getSourceExpr());
641 EmitFinalDestCopy(e->getType(), CGF.getOrCreateOpaqueLValueMapping(e));
645 AggExprEmitter::VisitCompoundLiteralExpr(CompoundLiteralExpr *E) {
646 if (Dest.isPotentiallyAliased() &&
647 E->getType().isPODType(CGF.getContext())) {
648 // For a POD type, just emit a load of the lvalue + a copy, because our
649 // compound literal might alias the destination.
650 EmitAggLoadOfLValue(E);
654 AggValueSlot Slot = EnsureSlot(E->getType());
655 CGF.EmitAggExpr(E->getInitializer(), Slot);
658 /// Attempt to look through various unimportant expressions to find a
659 /// cast of the given kind.
660 static Expr *findPeephole(Expr *op, CastKind kind) {
662 op = op->IgnoreParens();
663 if (CastExpr *castE = dyn_cast<CastExpr>(op)) {
664 if (castE->getCastKind() == kind)
665 return castE->getSubExpr();
666 if (castE->getCastKind() == CK_NoOp)
673 void AggExprEmitter::VisitCastExpr(CastExpr *E) {
674 if (const auto *ECE = dyn_cast<ExplicitCastExpr>(E))
675 CGF.CGM.EmitExplicitCastExprType(ECE, &CGF);
676 switch (E->getCastKind()) {
678 // FIXME: Can this actually happen? We have no test coverage for it.
679 assert(isa<CXXDynamicCastExpr>(E) && "CK_Dynamic without a dynamic_cast?");
680 LValue LV = CGF.EmitCheckedLValue(E->getSubExpr(),
681 CodeGenFunction::TCK_Load);
682 // FIXME: Do we also need to handle property references here?
684 CGF.EmitDynamicCast(LV.getAddress(), cast<CXXDynamicCastExpr>(E));
686 CGF.CGM.ErrorUnsupported(E, "non-simple lvalue dynamic_cast");
688 if (!Dest.isIgnored())
689 CGF.CGM.ErrorUnsupported(E, "lvalue dynamic_cast with a destination");
694 // Evaluate even if the destination is ignored.
695 if (Dest.isIgnored()) {
696 CGF.EmitAnyExpr(E->getSubExpr(), AggValueSlot::ignored(),
697 /*ignoreResult=*/true);
701 // GCC union extension
702 QualType Ty = E->getSubExpr()->getType();
704 Builder.CreateElementBitCast(Dest.getAddress(), CGF.ConvertType(Ty));
705 EmitInitializationToLValue(E->getSubExpr(),
706 CGF.MakeAddrLValue(CastPtr, Ty));
710 case CK_DerivedToBase:
711 case CK_BaseToDerived:
712 case CK_UncheckedDerivedToBase: {
713 llvm_unreachable("cannot perform hierarchy conversion in EmitAggExpr: "
714 "should have been unpacked before we got here");
717 case CK_NonAtomicToAtomic:
718 case CK_AtomicToNonAtomic: {
719 bool isToAtomic = (E->getCastKind() == CK_NonAtomicToAtomic);
721 // Determine the atomic and value types.
722 QualType atomicType = E->getSubExpr()->getType();
723 QualType valueType = E->getType();
724 if (isToAtomic) std::swap(atomicType, valueType);
726 assert(atomicType->isAtomicType());
727 assert(CGF.getContext().hasSameUnqualifiedType(valueType,
728 atomicType->castAs<AtomicType>()->getValueType()));
730 // Just recurse normally if we're ignoring the result or the
731 // atomic type doesn't change representation.
732 if (Dest.isIgnored() || !CGF.CGM.isPaddedAtomicType(atomicType)) {
733 return Visit(E->getSubExpr());
736 CastKind peepholeTarget =
737 (isToAtomic ? CK_AtomicToNonAtomic : CK_NonAtomicToAtomic);
739 // These two cases are reverses of each other; try to peephole them.
740 if (Expr *op = findPeephole(E->getSubExpr(), peepholeTarget)) {
741 assert(CGF.getContext().hasSameUnqualifiedType(op->getType(),
743 "peephole significantly changed types?");
747 // If we're converting an r-value of non-atomic type to an r-value
748 // of atomic type, just emit directly into the relevant sub-object.
750 AggValueSlot valueDest = Dest;
751 if (!valueDest.isIgnored() && CGF.CGM.isPaddedAtomicType(atomicType)) {
752 // Zero-initialize. (Strictly speaking, we only need to initialize
753 // the padding at the end, but this is simpler.)
754 if (!Dest.isZeroed())
755 CGF.EmitNullInitialization(Dest.getAddress(), atomicType);
757 // Build a GEP to refer to the subobject.
759 CGF.Builder.CreateStructGEP(valueDest.getAddress(), 0,
761 valueDest = AggValueSlot::forAddr(valueAddr,
762 valueDest.getQualifiers(),
763 valueDest.isExternallyDestructed(),
764 valueDest.requiresGCollection(),
765 valueDest.isPotentiallyAliased(),
766 AggValueSlot::DoesNotOverlap,
767 AggValueSlot::IsZeroed);
770 CGF.EmitAggExpr(E->getSubExpr(), valueDest);
774 // Otherwise, we're converting an atomic type to a non-atomic type.
775 // Make an atomic temporary, emit into that, and then copy the value out.
776 AggValueSlot atomicSlot =
777 CGF.CreateAggTemp(atomicType, "atomic-to-nonatomic.temp");
778 CGF.EmitAggExpr(E->getSubExpr(), atomicSlot);
781 Builder.CreateStructGEP(atomicSlot.getAddress(), 0, CharUnits());
782 RValue rvalue = RValue::getAggregate(valueAddr, atomicSlot.isVolatile());
783 return EmitFinalDestCopy(valueType, rvalue);
786 case CK_LValueToRValue:
787 // If we're loading from a volatile type, force the destination
789 if (E->getSubExpr()->getType().isVolatileQualified()) {
790 EnsureDest(E->getType());
791 return Visit(E->getSubExpr());
797 case CK_UserDefinedConversion:
798 case CK_ConstructorConversion:
799 assert(CGF.getContext().hasSameUnqualifiedType(E->getSubExpr()->getType(),
801 "Implicit cast types must be compatible");
802 Visit(E->getSubExpr());
805 case CK_LValueBitCast:
806 llvm_unreachable("should not be emitting lvalue bitcast as rvalue");
810 case CK_ArrayToPointerDecay:
811 case CK_FunctionToPointerDecay:
812 case CK_NullToPointer:
813 case CK_NullToMemberPointer:
814 case CK_BaseToDerivedMemberPointer:
815 case CK_DerivedToBaseMemberPointer:
816 case CK_MemberPointerToBoolean:
817 case CK_ReinterpretMemberPointer:
818 case CK_IntegralToPointer:
819 case CK_PointerToIntegral:
820 case CK_PointerToBoolean:
823 case CK_IntegralCast:
824 case CK_BooleanToSignedIntegral:
825 case CK_IntegralToBoolean:
826 case CK_IntegralToFloating:
827 case CK_FloatingToIntegral:
828 case CK_FloatingToBoolean:
829 case CK_FloatingCast:
830 case CK_CPointerToObjCPointerCast:
831 case CK_BlockPointerToObjCPointerCast:
832 case CK_AnyPointerToBlockPointerCast:
833 case CK_ObjCObjectLValueCast:
834 case CK_FloatingRealToComplex:
835 case CK_FloatingComplexToReal:
836 case CK_FloatingComplexToBoolean:
837 case CK_FloatingComplexCast:
838 case CK_FloatingComplexToIntegralComplex:
839 case CK_IntegralRealToComplex:
840 case CK_IntegralComplexToReal:
841 case CK_IntegralComplexToBoolean:
842 case CK_IntegralComplexCast:
843 case CK_IntegralComplexToFloatingComplex:
844 case CK_ARCProduceObject:
845 case CK_ARCConsumeObject:
846 case CK_ARCReclaimReturnedObject:
847 case CK_ARCExtendBlockObject:
848 case CK_CopyAndAutoreleaseBlockObject:
849 case CK_BuiltinFnToFnPtr:
850 case CK_ZeroToOCLEvent:
851 case CK_ZeroToOCLQueue:
852 case CK_AddressSpaceConversion:
853 case CK_IntToOCLSampler:
854 llvm_unreachable("cast kind invalid for aggregate types");
858 void AggExprEmitter::VisitCallExpr(const CallExpr *E) {
859 if (E->getCallReturnType(CGF.getContext())->isReferenceType()) {
860 EmitAggLoadOfLValue(E);
864 withReturnValueSlot(E, [&](ReturnValueSlot Slot) {
865 return CGF.EmitCallExpr(E, Slot);
869 void AggExprEmitter::VisitObjCMessageExpr(ObjCMessageExpr *E) {
870 withReturnValueSlot(E, [&](ReturnValueSlot Slot) {
871 return CGF.EmitObjCMessageExpr(E, Slot);
875 void AggExprEmitter::VisitBinComma(const BinaryOperator *E) {
876 CGF.EmitIgnoredExpr(E->getLHS());
880 void AggExprEmitter::VisitStmtExpr(const StmtExpr *E) {
881 CodeGenFunction::StmtExprEvaluation eval(CGF);
882 CGF.EmitCompoundStmt(*E->getSubStmt(), true, Dest);
891 static llvm::Value *EmitCompare(CGBuilderTy &Builder, CodeGenFunction &CGF,
892 const BinaryOperator *E, llvm::Value *LHS,
893 llvm::Value *RHS, CompareKind Kind,
894 const char *NameSuffix = "") {
895 QualType ArgTy = E->getLHS()->getType();
896 if (const ComplexType *CT = ArgTy->getAs<ComplexType>())
897 ArgTy = CT->getElementType();
899 if (const auto *MPT = ArgTy->getAs<MemberPointerType>()) {
900 assert(Kind == CK_Equal &&
901 "member pointers may only be compared for equality");
902 return CGF.CGM.getCXXABI().EmitMemberPointerComparison(
903 CGF, LHS, RHS, MPT, /*IsInequality*/ false);
906 // Compute the comparison instructions for the specified comparison kind.
909 llvm::CmpInst::Predicate FCmp;
910 llvm::CmpInst::Predicate SCmp;
911 llvm::CmpInst::Predicate UCmp;
913 CmpInstInfo InstInfo = [&]() -> CmpInstInfo {
914 using FI = llvm::FCmpInst;
915 using II = llvm::ICmpInst;
918 return {"cmp.lt", FI::FCMP_OLT, II::ICMP_SLT, II::ICMP_ULT};
920 return {"cmp.gt", FI::FCMP_OGT, II::ICMP_SGT, II::ICMP_UGT};
922 return {"cmp.eq", FI::FCMP_OEQ, II::ICMP_EQ, II::ICMP_EQ};
924 llvm_unreachable("Unrecognised CompareKind enum");
927 if (ArgTy->hasFloatingRepresentation())
928 return Builder.CreateFCmp(InstInfo.FCmp, LHS, RHS,
929 llvm::Twine(InstInfo.Name) + NameSuffix);
930 if (ArgTy->isIntegralOrEnumerationType() || ArgTy->isPointerType()) {
932 ArgTy->hasSignedIntegerRepresentation() ? InstInfo.SCmp : InstInfo.UCmp;
933 return Builder.CreateICmp(Inst, LHS, RHS,
934 llvm::Twine(InstInfo.Name) + NameSuffix);
937 llvm_unreachable("unsupported aggregate binary expression should have "
938 "already been handled");
941 void AggExprEmitter::VisitBinCmp(const BinaryOperator *E) {
942 using llvm::BasicBlock;
945 assert(CGF.getContext().hasSameType(E->getLHS()->getType(),
946 E->getRHS()->getType()));
947 const ComparisonCategoryInfo &CmpInfo =
948 CGF.getContext().CompCategories.getInfoForType(E->getType());
949 assert(CmpInfo.Record->isTriviallyCopyable() &&
950 "cannot copy non-trivially copyable aggregate");
952 QualType ArgTy = E->getLHS()->getType();
954 // TODO: Handle comparing these types.
955 if (ArgTy->isVectorType())
956 return CGF.ErrorUnsupported(
957 E, "aggregate three-way comparison with vector arguments");
958 if (!ArgTy->isIntegralOrEnumerationType() && !ArgTy->isRealFloatingType() &&
959 !ArgTy->isNullPtrType() && !ArgTy->isPointerType() &&
960 !ArgTy->isMemberPointerType() && !ArgTy->isAnyComplexType()) {
961 return CGF.ErrorUnsupported(E, "aggregate three-way comparison");
963 bool IsComplex = ArgTy->isAnyComplexType();
965 // Evaluate the operands to the expression and extract their values.
966 auto EmitOperand = [&](Expr *E) -> std::pair<Value *, Value *> {
967 RValue RV = CGF.EmitAnyExpr(E);
969 return {RV.getScalarVal(), nullptr};
970 if (RV.isAggregate())
971 return {RV.getAggregatePointer(), nullptr};
972 assert(RV.isComplex());
973 return RV.getComplexVal();
975 auto LHSValues = EmitOperand(E->getLHS()),
976 RHSValues = EmitOperand(E->getRHS());
978 auto EmitCmp = [&](CompareKind K) {
979 Value *Cmp = EmitCompare(Builder, CGF, E, LHSValues.first, RHSValues.first,
980 K, IsComplex ? ".r" : "");
983 assert(K == CompareKind::CK_Equal);
984 Value *CmpImag = EmitCompare(Builder, CGF, E, LHSValues.second,
985 RHSValues.second, K, ".i");
986 return Builder.CreateAnd(Cmp, CmpImag, "and.eq");
988 auto EmitCmpRes = [&](const ComparisonCategoryInfo::ValueInfo *VInfo) {
989 return Builder.getInt(VInfo->getIntValue());
993 if (ArgTy->isNullPtrType()) {
994 Select = EmitCmpRes(CmpInfo.getEqualOrEquiv());
995 } else if (CmpInfo.isEquality()) {
996 Select = Builder.CreateSelect(
997 EmitCmp(CK_Equal), EmitCmpRes(CmpInfo.getEqualOrEquiv()),
998 EmitCmpRes(CmpInfo.getNonequalOrNonequiv()), "sel.eq");
999 } else if (!CmpInfo.isPartial()) {
1001 Builder.CreateSelect(EmitCmp(CK_Less), EmitCmpRes(CmpInfo.getLess()),
1002 EmitCmpRes(CmpInfo.getGreater()), "sel.lt");
1003 Select = Builder.CreateSelect(EmitCmp(CK_Equal),
1004 EmitCmpRes(CmpInfo.getEqualOrEquiv()),
1005 SelectOne, "sel.eq");
1007 Value *SelectEq = Builder.CreateSelect(
1008 EmitCmp(CK_Equal), EmitCmpRes(CmpInfo.getEqualOrEquiv()),
1009 EmitCmpRes(CmpInfo.getUnordered()), "sel.eq");
1010 Value *SelectGT = Builder.CreateSelect(EmitCmp(CK_Greater),
1011 EmitCmpRes(CmpInfo.getGreater()),
1012 SelectEq, "sel.gt");
1013 Select = Builder.CreateSelect(
1014 EmitCmp(CK_Less), EmitCmpRes(CmpInfo.getLess()), SelectGT, "sel.lt");
1016 // Create the return value in the destination slot.
1017 EnsureDest(E->getType());
1018 LValue DestLV = CGF.MakeAddrLValue(Dest.getAddress(), E->getType());
1020 // Emit the address of the first (and only) field in the comparison category
1021 // type, and initialize it from the constant integer value selected above.
1022 LValue FieldLV = CGF.EmitLValueForFieldInitialization(
1023 DestLV, *CmpInfo.Record->field_begin());
1024 CGF.EmitStoreThroughLValue(RValue::get(Select), FieldLV, /*IsInit*/ true);
1026 // All done! The result is in the Dest slot.
1029 void AggExprEmitter::VisitBinaryOperator(const BinaryOperator *E) {
1030 if (E->getOpcode() == BO_PtrMemD || E->getOpcode() == BO_PtrMemI)
1031 VisitPointerToDataMemberBinaryOperator(E);
1033 CGF.ErrorUnsupported(E, "aggregate binary expression");
1036 void AggExprEmitter::VisitPointerToDataMemberBinaryOperator(
1037 const BinaryOperator *E) {
1038 LValue LV = CGF.EmitPointerToDataMemberBinaryExpr(E);
1039 EmitFinalDestCopy(E->getType(), LV);
1042 /// Is the value of the given expression possibly a reference to or
1043 /// into a __block variable?
1044 static bool isBlockVarRef(const Expr *E) {
1045 // Make sure we look through parens.
1046 E = E->IgnoreParens();
1048 // Check for a direct reference to a __block variable.
1049 if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E)) {
1050 const VarDecl *var = dyn_cast<VarDecl>(DRE->getDecl());
1051 return (var && var->hasAttr<BlocksAttr>());
1054 // More complicated stuff.
1056 // Binary operators.
1057 if (const BinaryOperator *op = dyn_cast<BinaryOperator>(E)) {
1058 // For an assignment or pointer-to-member operation, just care
1060 if (op->isAssignmentOp() || op->isPtrMemOp())
1061 return isBlockVarRef(op->getLHS());
1063 // For a comma, just care about the RHS.
1064 if (op->getOpcode() == BO_Comma)
1065 return isBlockVarRef(op->getRHS());
1067 // FIXME: pointer arithmetic?
1070 // Check both sides of a conditional operator.
1071 } else if (const AbstractConditionalOperator *op
1072 = dyn_cast<AbstractConditionalOperator>(E)) {
1073 return isBlockVarRef(op->getTrueExpr())
1074 || isBlockVarRef(op->getFalseExpr());
1076 // OVEs are required to support BinaryConditionalOperators.
1077 } else if (const OpaqueValueExpr *op
1078 = dyn_cast<OpaqueValueExpr>(E)) {
1079 if (const Expr *src = op->getSourceExpr())
1080 return isBlockVarRef(src);
1082 // Casts are necessary to get things like (*(int*)&var) = foo().
1083 // We don't really care about the kind of cast here, except
1084 // we don't want to look through l2r casts, because it's okay
1085 // to get the *value* in a __block variable.
1086 } else if (const CastExpr *cast = dyn_cast<CastExpr>(E)) {
1087 if (cast->getCastKind() == CK_LValueToRValue)
1089 return isBlockVarRef(cast->getSubExpr());
1091 // Handle unary operators. Again, just aggressively look through
1092 // it, ignoring the operation.
1093 } else if (const UnaryOperator *uop = dyn_cast<UnaryOperator>(E)) {
1094 return isBlockVarRef(uop->getSubExpr());
1096 // Look into the base of a field access.
1097 } else if (const MemberExpr *mem = dyn_cast<MemberExpr>(E)) {
1098 return isBlockVarRef(mem->getBase());
1100 // Look into the base of a subscript.
1101 } else if (const ArraySubscriptExpr *sub = dyn_cast<ArraySubscriptExpr>(E)) {
1102 return isBlockVarRef(sub->getBase());
1108 void AggExprEmitter::VisitBinAssign(const BinaryOperator *E) {
1109 // For an assignment to work, the value on the right has
1110 // to be compatible with the value on the left.
1111 assert(CGF.getContext().hasSameUnqualifiedType(E->getLHS()->getType(),
1112 E->getRHS()->getType())
1113 && "Invalid assignment");
1115 // If the LHS might be a __block variable, and the RHS can
1116 // potentially cause a block copy, we need to evaluate the RHS first
1117 // so that the assignment goes the right place.
1118 // This is pretty semantically fragile.
1119 if (isBlockVarRef(E->getLHS()) &&
1120 E->getRHS()->HasSideEffects(CGF.getContext())) {
1121 // Ensure that we have a destination, and evaluate the RHS into that.
1122 EnsureDest(E->getRHS()->getType());
1125 // Now emit the LHS and copy into it.
1126 LValue LHS = CGF.EmitCheckedLValue(E->getLHS(), CodeGenFunction::TCK_Store);
1128 // That copy is an atomic copy if the LHS is atomic.
1129 if (LHS.getType()->isAtomicType() ||
1130 CGF.LValueIsSuitableForInlineAtomic(LHS)) {
1131 CGF.EmitAtomicStore(Dest.asRValue(), LHS, /*isInit*/ false);
1135 EmitCopy(E->getLHS()->getType(),
1136 AggValueSlot::forLValue(LHS, AggValueSlot::IsDestructed,
1137 needsGC(E->getLHS()->getType()),
1138 AggValueSlot::IsAliased,
1139 AggValueSlot::MayOverlap),
1144 LValue LHS = CGF.EmitLValue(E->getLHS());
1146 // If we have an atomic type, evaluate into the destination and then
1147 // do an atomic copy.
1148 if (LHS.getType()->isAtomicType() ||
1149 CGF.LValueIsSuitableForInlineAtomic(LHS)) {
1150 EnsureDest(E->getRHS()->getType());
1152 CGF.EmitAtomicStore(Dest.asRValue(), LHS, /*isInit*/ false);
1156 // Codegen the RHS so that it stores directly into the LHS.
1157 AggValueSlot LHSSlot =
1158 AggValueSlot::forLValue(LHS, AggValueSlot::IsDestructed,
1159 needsGC(E->getLHS()->getType()),
1160 AggValueSlot::IsAliased,
1161 AggValueSlot::MayOverlap);
1162 // A non-volatile aggregate destination might have volatile member.
1163 if (!LHSSlot.isVolatile() &&
1164 CGF.hasVolatileMember(E->getLHS()->getType()))
1165 LHSSlot.setVolatile(true);
1167 CGF.EmitAggExpr(E->getRHS(), LHSSlot);
1169 // Copy into the destination if the assignment isn't ignored.
1170 EmitFinalDestCopy(E->getType(), LHS);
1173 void AggExprEmitter::
1174 VisitAbstractConditionalOperator(const AbstractConditionalOperator *E) {
1175 llvm::BasicBlock *LHSBlock = CGF.createBasicBlock("cond.true");
1176 llvm::BasicBlock *RHSBlock = CGF.createBasicBlock("cond.false");
1177 llvm::BasicBlock *ContBlock = CGF.createBasicBlock("cond.end");
1179 // Bind the common expression if necessary.
1180 CodeGenFunction::OpaqueValueMapping binding(CGF, E);
1182 CodeGenFunction::ConditionalEvaluation eval(CGF);
1183 CGF.EmitBranchOnBoolExpr(E->getCond(), LHSBlock, RHSBlock,
1184 CGF.getProfileCount(E));
1186 // Save whether the destination's lifetime is externally managed.
1187 bool isExternallyDestructed = Dest.isExternallyDestructed();
1190 CGF.EmitBlock(LHSBlock);
1191 CGF.incrementProfileCounter(E);
1192 Visit(E->getTrueExpr());
1195 assert(CGF.HaveInsertPoint() && "expression evaluation ended with no IP!");
1196 CGF.Builder.CreateBr(ContBlock);
1198 // If the result of an agg expression is unused, then the emission
1199 // of the LHS might need to create a destination slot. That's fine
1200 // with us, and we can safely emit the RHS into the same slot, but
1201 // we shouldn't claim that it's already being destructed.
1202 Dest.setExternallyDestructed(isExternallyDestructed);
1205 CGF.EmitBlock(RHSBlock);
1206 Visit(E->getFalseExpr());
1209 CGF.EmitBlock(ContBlock);
1212 void AggExprEmitter::VisitChooseExpr(const ChooseExpr *CE) {
1213 Visit(CE->getChosenSubExpr());
1216 void AggExprEmitter::VisitVAArgExpr(VAArgExpr *VE) {
1217 Address ArgValue = Address::invalid();
1218 Address ArgPtr = CGF.EmitVAArg(VE, ArgValue);
1220 // If EmitVAArg fails, emit an error.
1221 if (!ArgPtr.isValid()) {
1222 CGF.ErrorUnsupported(VE, "aggregate va_arg expression");
1226 EmitFinalDestCopy(VE->getType(), CGF.MakeAddrLValue(ArgPtr, VE->getType()));
1229 void AggExprEmitter::VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E) {
1230 // Ensure that we have a slot, but if we already do, remember
1231 // whether it was externally destructed.
1232 bool wasExternallyDestructed = Dest.isExternallyDestructed();
1233 EnsureDest(E->getType());
1235 // We're going to push a destructor if there isn't already one.
1236 Dest.setExternallyDestructed();
1238 Visit(E->getSubExpr());
1240 // Push that destructor we promised.
1241 if (!wasExternallyDestructed)
1242 CGF.EmitCXXTemporary(E->getTemporary(), E->getType(), Dest.getAddress());
1246 AggExprEmitter::VisitCXXConstructExpr(const CXXConstructExpr *E) {
1247 AggValueSlot Slot = EnsureSlot(E->getType());
1248 CGF.EmitCXXConstructExpr(E, Slot);
1251 void AggExprEmitter::VisitCXXInheritedCtorInitExpr(
1252 const CXXInheritedCtorInitExpr *E) {
1253 AggValueSlot Slot = EnsureSlot(E->getType());
1254 CGF.EmitInheritedCXXConstructorCall(
1255 E->getConstructor(), E->constructsVBase(), Slot.getAddress(),
1256 E->inheritedFromVBase(), E);
1260 AggExprEmitter::VisitLambdaExpr(LambdaExpr *E) {
1261 AggValueSlot Slot = EnsureSlot(E->getType());
1262 CGF.EmitLambdaExpr(E, Slot);
1265 void AggExprEmitter::VisitExprWithCleanups(ExprWithCleanups *E) {
1266 CGF.enterFullExpression(E);
1267 CodeGenFunction::RunCleanupsScope cleanups(CGF);
1268 Visit(E->getSubExpr());
1271 void AggExprEmitter::VisitCXXScalarValueInitExpr(CXXScalarValueInitExpr *E) {
1272 QualType T = E->getType();
1273 AggValueSlot Slot = EnsureSlot(T);
1274 EmitNullInitializationToLValue(CGF.MakeAddrLValue(Slot.getAddress(), T));
1277 void AggExprEmitter::VisitImplicitValueInitExpr(ImplicitValueInitExpr *E) {
1278 QualType T = E->getType();
1279 AggValueSlot Slot = EnsureSlot(T);
1280 EmitNullInitializationToLValue(CGF.MakeAddrLValue(Slot.getAddress(), T));
1283 /// isSimpleZero - If emitting this value will obviously just cause a store of
1284 /// zero to memory, return true. This can return false if uncertain, so it just
1285 /// handles simple cases.
1286 static bool isSimpleZero(const Expr *E, CodeGenFunction &CGF) {
1287 E = E->IgnoreParens();
1290 if (const IntegerLiteral *IL = dyn_cast<IntegerLiteral>(E))
1291 return IL->getValue() == 0;
1293 if (const FloatingLiteral *FL = dyn_cast<FloatingLiteral>(E))
1294 return FL->getValue().isPosZero();
1296 if ((isa<ImplicitValueInitExpr>(E) || isa<CXXScalarValueInitExpr>(E)) &&
1297 CGF.getTypes().isZeroInitializable(E->getType()))
1299 // (int*)0 - Null pointer expressions.
1300 if (const CastExpr *ICE = dyn_cast<CastExpr>(E))
1301 return ICE->getCastKind() == CK_NullToPointer &&
1302 CGF.getTypes().isPointerZeroInitializable(E->getType());
1304 if (const CharacterLiteral *CL = dyn_cast<CharacterLiteral>(E))
1305 return CL->getValue() == 0;
1307 // Otherwise, hard case: conservatively return false.
1313 AggExprEmitter::EmitInitializationToLValue(Expr *E, LValue LV) {
1314 QualType type = LV.getType();
1315 // FIXME: Ignore result?
1316 // FIXME: Are initializers affected by volatile?
1317 if (Dest.isZeroed() && isSimpleZero(E, CGF)) {
1318 // Storing "i32 0" to a zero'd memory location is a noop.
1320 } else if (isa<ImplicitValueInitExpr>(E) || isa<CXXScalarValueInitExpr>(E)) {
1321 return EmitNullInitializationToLValue(LV);
1322 } else if (isa<NoInitExpr>(E)) {
1325 } else if (type->isReferenceType()) {
1326 RValue RV = CGF.EmitReferenceBindingToExpr(E);
1327 return CGF.EmitStoreThroughLValue(RV, LV);
1330 switch (CGF.getEvaluationKind(type)) {
1332 CGF.EmitComplexExprIntoLValue(E, LV, /*isInit*/ true);
1335 CGF.EmitAggExpr(E, AggValueSlot::forLValue(LV,
1336 AggValueSlot::IsDestructed,
1337 AggValueSlot::DoesNotNeedGCBarriers,
1338 AggValueSlot::IsNotAliased,
1339 AggValueSlot::MayOverlap,
1343 if (LV.isSimple()) {
1344 CGF.EmitScalarInit(E, /*D=*/nullptr, LV, /*Captured=*/false);
1346 CGF.EmitStoreThroughLValue(RValue::get(CGF.EmitScalarExpr(E)), LV);
1350 llvm_unreachable("bad evaluation kind");
1353 void AggExprEmitter::EmitNullInitializationToLValue(LValue lv) {
1354 QualType type = lv.getType();
1356 // If the destination slot is already zeroed out before the aggregate is
1357 // copied into it, we don't have to emit any zeros here.
1358 if (Dest.isZeroed() && CGF.getTypes().isZeroInitializable(type))
1361 if (CGF.hasScalarEvaluationKind(type)) {
1362 // For non-aggregates, we can store the appropriate null constant.
1363 llvm::Value *null = CGF.CGM.EmitNullConstant(type);
1364 // Note that the following is not equivalent to
1365 // EmitStoreThroughBitfieldLValue for ARC types.
1366 if (lv.isBitField()) {
1367 CGF.EmitStoreThroughBitfieldLValue(RValue::get(null), lv);
1369 assert(lv.isSimple());
1370 CGF.EmitStoreOfScalar(null, lv, /* isInitialization */ true);
1373 // There's a potential optimization opportunity in combining
1374 // memsets; that would be easy for arrays, but relatively
1375 // difficult for structures with the current code.
1376 CGF.EmitNullInitialization(lv.getAddress(), lv.getType());
1380 void AggExprEmitter::VisitInitListExpr(InitListExpr *E) {
1382 // FIXME: Assess perf here? Figure out what cases are worth optimizing here
1383 // (Length of globals? Chunks of zeroed-out space?).
1385 // If we can, prefer a copy from a global; this is a lot less code for long
1386 // globals, and it's easier for the current optimizers to analyze.
1387 if (llvm::Constant* C = CGF.CGM.EmitConstantExpr(E, E->getType(), &CGF)) {
1388 llvm::GlobalVariable* GV =
1389 new llvm::GlobalVariable(CGF.CGM.getModule(), C->getType(), true,
1390 llvm::GlobalValue::InternalLinkage, C, "");
1391 EmitFinalDestCopy(E->getType(), CGF.MakeAddrLValue(GV, E->getType()));
1395 if (E->hadArrayRangeDesignator())
1396 CGF.ErrorUnsupported(E, "GNU array range designator extension");
1398 if (E->isTransparent())
1399 return Visit(E->getInit(0));
1401 AggValueSlot Dest = EnsureSlot(E->getType());
1403 LValue DestLV = CGF.MakeAddrLValue(Dest.getAddress(), E->getType());
1405 // Handle initialization of an array.
1406 if (E->getType()->isArrayType()) {
1407 auto AType = cast<llvm::ArrayType>(Dest.getAddress().getElementType());
1408 EmitArrayInit(Dest.getAddress(), AType, E->getType(), E);
1412 assert(E->getType()->isRecordType() && "Only support structs/unions here!");
1414 // Do struct initialization; this code just sets each individual member
1415 // to the approprate value. This makes bitfield support automatic;
1416 // the disadvantage is that the generated code is more difficult for
1417 // the optimizer, especially with bitfields.
1418 unsigned NumInitElements = E->getNumInits();
1419 RecordDecl *record = E->getType()->castAs<RecordType>()->getDecl();
1421 // We'll need to enter cleanup scopes in case any of the element
1422 // initializers throws an exception.
1423 SmallVector<EHScopeStack::stable_iterator, 16> cleanups;
1424 llvm::Instruction *cleanupDominator = nullptr;
1426 unsigned curInitIndex = 0;
1428 // Emit initialization of base classes.
1429 if (auto *CXXRD = dyn_cast<CXXRecordDecl>(record)) {
1430 assert(E->getNumInits() >= CXXRD->getNumBases() &&
1431 "missing initializer for base class");
1432 for (auto &Base : CXXRD->bases()) {
1433 assert(!Base.isVirtual() && "should not see vbases here");
1434 auto *BaseRD = Base.getType()->getAsCXXRecordDecl();
1435 Address V = CGF.GetAddressOfDirectBaseInCompleteClass(
1436 Dest.getAddress(), CXXRD, BaseRD,
1437 /*isBaseVirtual*/ false);
1438 AggValueSlot AggSlot = AggValueSlot::forAddr(
1440 AggValueSlot::IsDestructed,
1441 AggValueSlot::DoesNotNeedGCBarriers,
1442 AggValueSlot::IsNotAliased,
1443 CGF.overlapForBaseInit(CXXRD, BaseRD, Base.isVirtual()));
1444 CGF.EmitAggExpr(E->getInit(curInitIndex++), AggSlot);
1446 if (QualType::DestructionKind dtorKind =
1447 Base.getType().isDestructedType()) {
1448 CGF.pushDestroy(dtorKind, V, Base.getType());
1449 cleanups.push_back(CGF.EHStack.stable_begin());
1454 // Prepare a 'this' for CXXDefaultInitExprs.
1455 CodeGenFunction::FieldConstructionScope FCS(CGF, Dest.getAddress());
1457 if (record->isUnion()) {
1458 // Only initialize one field of a union. The field itself is
1459 // specified by the initializer list.
1460 if (!E->getInitializedFieldInUnion()) {
1461 // Empty union; we have nothing to do.
1464 // Make sure that it's really an empty and not a failure of
1465 // semantic analysis.
1466 for (const auto *Field : record->fields())
1467 assert(Field->isUnnamedBitfield() && "Only unnamed bitfields allowed");
1472 // FIXME: volatility
1473 FieldDecl *Field = E->getInitializedFieldInUnion();
1475 LValue FieldLoc = CGF.EmitLValueForFieldInitialization(DestLV, Field);
1476 if (NumInitElements) {
1477 // Store the initializer into the field
1478 EmitInitializationToLValue(E->getInit(0), FieldLoc);
1480 // Default-initialize to null.
1481 EmitNullInitializationToLValue(FieldLoc);
1487 // Here we iterate over the fields; this makes it simpler to both
1488 // default-initialize fields and skip over unnamed fields.
1489 for (const auto *field : record->fields()) {
1490 // We're done once we hit the flexible array member.
1491 if (field->getType()->isIncompleteArrayType())
1494 // Always skip anonymous bitfields.
1495 if (field->isUnnamedBitfield())
1498 // We're done if we reach the end of the explicit initializers, we
1499 // have a zeroed object, and the rest of the fields are
1500 // zero-initializable.
1501 if (curInitIndex == NumInitElements && Dest.isZeroed() &&
1502 CGF.getTypes().isZeroInitializable(E->getType()))
1506 LValue LV = CGF.EmitLValueForFieldInitialization(DestLV, field);
1507 // We never generate write-barries for initialized fields.
1510 if (curInitIndex < NumInitElements) {
1511 // Store the initializer into the field.
1512 EmitInitializationToLValue(E->getInit(curInitIndex++), LV);
1514 // We're out of initializers; default-initialize to null
1515 EmitNullInitializationToLValue(LV);
1518 // Push a destructor if necessary.
1519 // FIXME: if we have an array of structures, all explicitly
1520 // initialized, we can end up pushing a linear number of cleanups.
1521 bool pushedCleanup = false;
1522 if (QualType::DestructionKind dtorKind
1523 = field->getType().isDestructedType()) {
1524 assert(LV.isSimple());
1525 if (CGF.needsEHCleanup(dtorKind)) {
1526 if (!cleanupDominator)
1527 cleanupDominator = CGF.Builder.CreateAlignedLoad(
1529 llvm::Constant::getNullValue(CGF.Int8PtrTy),
1530 CharUnits::One()); // placeholder
1532 CGF.pushDestroy(EHCleanup, LV.getAddress(), field->getType(),
1533 CGF.getDestroyer(dtorKind), false);
1534 cleanups.push_back(CGF.EHStack.stable_begin());
1535 pushedCleanup = true;
1539 // If the GEP didn't get used because of a dead zero init or something
1540 // else, clean it up for -O0 builds and general tidiness.
1541 if (!pushedCleanup && LV.isSimple())
1542 if (llvm::GetElementPtrInst *GEP =
1543 dyn_cast<llvm::GetElementPtrInst>(LV.getPointer()))
1544 if (GEP->use_empty())
1545 GEP->eraseFromParent();
1548 // Deactivate all the partial cleanups in reverse order, which
1549 // generally means popping them.
1550 for (unsigned i = cleanups.size(); i != 0; --i)
1551 CGF.DeactivateCleanupBlock(cleanups[i-1], cleanupDominator);
1553 // Destroy the placeholder if we made one.
1554 if (cleanupDominator)
1555 cleanupDominator->eraseFromParent();
1558 void AggExprEmitter::VisitArrayInitLoopExpr(const ArrayInitLoopExpr *E,
1559 llvm::Value *outerBegin) {
1560 // Emit the common subexpression.
1561 CodeGenFunction::OpaqueValueMapping binding(CGF, E->getCommonExpr());
1563 Address destPtr = EnsureSlot(E->getType()).getAddress();
1564 uint64_t numElements = E->getArraySize().getZExtValue();
1569 // destPtr is an array*. Construct an elementType* by drilling down a level.
1570 llvm::Value *zero = llvm::ConstantInt::get(CGF.SizeTy, 0);
1571 llvm::Value *indices[] = {zero, zero};
1572 llvm::Value *begin = Builder.CreateInBoundsGEP(destPtr.getPointer(), indices,
1575 // Prepare to special-case multidimensional array initialization: we avoid
1576 // emitting multiple destructor loops in that case.
1579 ArrayInitLoopExpr *InnerLoop = dyn_cast<ArrayInitLoopExpr>(E->getSubExpr());
1581 QualType elementType =
1582 CGF.getContext().getAsArrayType(E->getType())->getElementType();
1583 CharUnits elementSize = CGF.getContext().getTypeSizeInChars(elementType);
1584 CharUnits elementAlign =
1585 destPtr.getAlignment().alignmentOfArrayElement(elementSize);
1587 llvm::BasicBlock *entryBB = Builder.GetInsertBlock();
1588 llvm::BasicBlock *bodyBB = CGF.createBasicBlock("arrayinit.body");
1590 // Jump into the body.
1591 CGF.EmitBlock(bodyBB);
1592 llvm::PHINode *index =
1593 Builder.CreatePHI(zero->getType(), 2, "arrayinit.index");
1594 index->addIncoming(zero, entryBB);
1595 llvm::Value *element = Builder.CreateInBoundsGEP(begin, index);
1597 // Prepare for a cleanup.
1598 QualType::DestructionKind dtorKind = elementType.isDestructedType();
1599 EHScopeStack::stable_iterator cleanup;
1600 if (CGF.needsEHCleanup(dtorKind) && !InnerLoop) {
1601 if (outerBegin->getType() != element->getType())
1602 outerBegin = Builder.CreateBitCast(outerBegin, element->getType());
1603 CGF.pushRegularPartialArrayCleanup(outerBegin, element, elementType,
1605 CGF.getDestroyer(dtorKind));
1606 cleanup = CGF.EHStack.stable_begin();
1608 dtorKind = QualType::DK_none;
1611 // Emit the actual filler expression.
1613 // Temporaries created in an array initialization loop are destroyed
1614 // at the end of each iteration.
1615 CodeGenFunction::RunCleanupsScope CleanupsScope(CGF);
1616 CodeGenFunction::ArrayInitLoopExprScope Scope(CGF, index);
1618 CGF.MakeAddrLValue(Address(element, elementAlign), elementType);
1621 // If the subexpression is an ArrayInitLoopExpr, share its cleanup.
1622 auto elementSlot = AggValueSlot::forLValue(
1623 elementLV, AggValueSlot::IsDestructed,
1624 AggValueSlot::DoesNotNeedGCBarriers,
1625 AggValueSlot::IsNotAliased,
1626 AggValueSlot::DoesNotOverlap);
1627 AggExprEmitter(CGF, elementSlot, false)
1628 .VisitArrayInitLoopExpr(InnerLoop, outerBegin);
1630 EmitInitializationToLValue(E->getSubExpr(), elementLV);
1633 // Move on to the next element.
1634 llvm::Value *nextIndex = Builder.CreateNUWAdd(
1635 index, llvm::ConstantInt::get(CGF.SizeTy, 1), "arrayinit.next");
1636 index->addIncoming(nextIndex, Builder.GetInsertBlock());
1638 // Leave the loop if we're done.
1639 llvm::Value *done = Builder.CreateICmpEQ(
1640 nextIndex, llvm::ConstantInt::get(CGF.SizeTy, numElements),
1642 llvm::BasicBlock *endBB = CGF.createBasicBlock("arrayinit.end");
1643 Builder.CreateCondBr(done, endBB, bodyBB);
1645 CGF.EmitBlock(endBB);
1647 // Leave the partial-array cleanup if we entered one.
1649 CGF.DeactivateCleanupBlock(cleanup, index);
1652 void AggExprEmitter::VisitDesignatedInitUpdateExpr(DesignatedInitUpdateExpr *E) {
1653 AggValueSlot Dest = EnsureSlot(E->getType());
1655 LValue DestLV = CGF.MakeAddrLValue(Dest.getAddress(), E->getType());
1656 EmitInitializationToLValue(E->getBase(), DestLV);
1657 VisitInitListExpr(E->getUpdater());
1660 //===----------------------------------------------------------------------===//
1661 // Entry Points into this File
1662 //===----------------------------------------------------------------------===//
1664 /// GetNumNonZeroBytesInInit - Get an approximate count of the number of
1665 /// non-zero bytes that will be stored when outputting the initializer for the
1666 /// specified initializer expression.
1667 static CharUnits GetNumNonZeroBytesInInit(const Expr *E, CodeGenFunction &CGF) {
1668 E = E->IgnoreParens();
1670 // 0 and 0.0 won't require any non-zero stores!
1671 if (isSimpleZero(E, CGF)) return CharUnits::Zero();
1673 // If this is an initlist expr, sum up the size of sizes of the (present)
1674 // elements. If this is something weird, assume the whole thing is non-zero.
1675 const InitListExpr *ILE = dyn_cast<InitListExpr>(E);
1676 while (ILE && ILE->isTransparent())
1677 ILE = dyn_cast<InitListExpr>(ILE->getInit(0));
1678 if (!ILE || !CGF.getTypes().isZeroInitializable(ILE->getType()))
1679 return CGF.getContext().getTypeSizeInChars(E->getType());
1681 // InitListExprs for structs have to be handled carefully. If there are
1682 // reference members, we need to consider the size of the reference, not the
1683 // referencee. InitListExprs for unions and arrays can't have references.
1684 if (const RecordType *RT = E->getType()->getAs<RecordType>()) {
1685 if (!RT->isUnionType()) {
1686 RecordDecl *SD = E->getType()->getAs<RecordType>()->getDecl();
1687 CharUnits NumNonZeroBytes = CharUnits::Zero();
1689 unsigned ILEElement = 0;
1690 if (auto *CXXRD = dyn_cast<CXXRecordDecl>(SD))
1691 while (ILEElement != CXXRD->getNumBases())
1693 GetNumNonZeroBytesInInit(ILE->getInit(ILEElement++), CGF);
1694 for (const auto *Field : SD->fields()) {
1695 // We're done once we hit the flexible array member or run out of
1696 // InitListExpr elements.
1697 if (Field->getType()->isIncompleteArrayType() ||
1698 ILEElement == ILE->getNumInits())
1700 if (Field->isUnnamedBitfield())
1703 const Expr *E = ILE->getInit(ILEElement++);
1705 // Reference values are always non-null and have the width of a pointer.
1706 if (Field->getType()->isReferenceType())
1707 NumNonZeroBytes += CGF.getContext().toCharUnitsFromBits(
1708 CGF.getTarget().getPointerWidth(0));
1710 NumNonZeroBytes += GetNumNonZeroBytesInInit(E, CGF);
1713 return NumNonZeroBytes;
1718 CharUnits NumNonZeroBytes = CharUnits::Zero();
1719 for (unsigned i = 0, e = ILE->getNumInits(); i != e; ++i)
1720 NumNonZeroBytes += GetNumNonZeroBytesInInit(ILE->getInit(i), CGF);
1721 return NumNonZeroBytes;
1724 /// CheckAggExprForMemSetUse - If the initializer is large and has a lot of
1725 /// zeros in it, emit a memset and avoid storing the individual zeros.
1727 static void CheckAggExprForMemSetUse(AggValueSlot &Slot, const Expr *E,
1728 CodeGenFunction &CGF) {
1729 // If the slot is already known to be zeroed, nothing to do. Don't mess with
1731 if (Slot.isZeroed() || Slot.isVolatile() || !Slot.getAddress().isValid())
1734 // C++ objects with a user-declared constructor don't need zero'ing.
1735 if (CGF.getLangOpts().CPlusPlus)
1736 if (const RecordType *RT = CGF.getContext()
1737 .getBaseElementType(E->getType())->getAs<RecordType>()) {
1738 const CXXRecordDecl *RD = cast<CXXRecordDecl>(RT->getDecl());
1739 if (RD->hasUserDeclaredConstructor())
1743 // If the type is 16-bytes or smaller, prefer individual stores over memset.
1744 CharUnits Size = Slot.getPreferredSize(CGF.getContext(), E->getType());
1745 if (Size <= CharUnits::fromQuantity(16))
1748 // Check to see if over 3/4 of the initializer are known to be zero. If so,
1749 // we prefer to emit memset + individual stores for the rest.
1750 CharUnits NumNonZeroBytes = GetNumNonZeroBytesInInit(E, CGF);
1751 if (NumNonZeroBytes*4 > Size)
1754 // Okay, it seems like a good idea to use an initial memset, emit the call.
1755 llvm::Constant *SizeVal = CGF.Builder.getInt64(Size.getQuantity());
1757 Address Loc = Slot.getAddress();
1758 Loc = CGF.Builder.CreateElementBitCast(Loc, CGF.Int8Ty);
1759 CGF.Builder.CreateMemSet(Loc, CGF.Builder.getInt8(0), SizeVal, false);
1761 // Tell the AggExprEmitter that the slot is known zero.
1768 /// EmitAggExpr - Emit the computation of the specified expression of aggregate
1769 /// type. The result is computed into DestPtr. Note that if DestPtr is null,
1770 /// the value of the aggregate expression is not needed. If VolatileDest is
1771 /// true, DestPtr cannot be 0.
1772 void CodeGenFunction::EmitAggExpr(const Expr *E, AggValueSlot Slot) {
1773 assert(E && hasAggregateEvaluationKind(E->getType()) &&
1774 "Invalid aggregate expression to emit");
1775 assert((Slot.getAddress().isValid() || Slot.isIgnored()) &&
1776 "slot has bits but no address");
1778 // Optimize the slot if possible.
1779 CheckAggExprForMemSetUse(Slot, E, *this);
1781 AggExprEmitter(*this, Slot, Slot.isIgnored()).Visit(const_cast<Expr*>(E));
1784 LValue CodeGenFunction::EmitAggExprToLValue(const Expr *E) {
1785 assert(hasAggregateEvaluationKind(E->getType()) && "Invalid argument!");
1786 Address Temp = CreateMemTemp(E->getType());
1787 LValue LV = MakeAddrLValue(Temp, E->getType());
1788 EmitAggExpr(E, AggValueSlot::forLValue(LV, AggValueSlot::IsNotDestructed,
1789 AggValueSlot::DoesNotNeedGCBarriers,
1790 AggValueSlot::IsNotAliased,
1791 AggValueSlot::DoesNotOverlap));
1795 AggValueSlot::Overlap_t CodeGenFunction::overlapForBaseInit(
1796 const CXXRecordDecl *RD, const CXXRecordDecl *BaseRD, bool IsVirtual) {
1797 // Virtual bases are initialized first, in address order, so there's never
1798 // any overlap during their initialization.
1800 // FIXME: Under P0840, this is no longer true: the tail padding of a vbase
1801 // of a field could be reused by a vbase of a containing class.
1803 return AggValueSlot::DoesNotOverlap;
1805 // If the base class is laid out entirely within the nvsize of the derived
1806 // class, its tail padding cannot yet be initialized, so we can issue
1807 // stores at the full width of the base class.
1808 const ASTRecordLayout &Layout = getContext().getASTRecordLayout(RD);
1809 if (Layout.getBaseClassOffset(BaseRD) +
1810 getContext().getASTRecordLayout(BaseRD).getSize() <=
1811 Layout.getNonVirtualSize())
1812 return AggValueSlot::DoesNotOverlap;
1814 // The tail padding may contain values we need to preserve.
1815 return AggValueSlot::MayOverlap;
1818 void CodeGenFunction::EmitAggregateCopy(LValue Dest, LValue Src, QualType Ty,
1819 AggValueSlot::Overlap_t MayOverlap,
1821 assert(!Ty->isAnyComplexType() && "Shouldn't happen for complex");
1823 Address DestPtr = Dest.getAddress();
1824 Address SrcPtr = Src.getAddress();
1826 if (getLangOpts().CPlusPlus) {
1827 if (const RecordType *RT = Ty->getAs<RecordType>()) {
1828 CXXRecordDecl *Record = cast<CXXRecordDecl>(RT->getDecl());
1829 assert((Record->hasTrivialCopyConstructor() ||
1830 Record->hasTrivialCopyAssignment() ||
1831 Record->hasTrivialMoveConstructor() ||
1832 Record->hasTrivialMoveAssignment() ||
1833 Record->isUnion()) &&
1834 "Trying to aggregate-copy a type without a trivial copy/move "
1835 "constructor or assignment operator");
1836 // Ignore empty classes in C++.
1837 if (Record->isEmpty())
1842 // Aggregate assignment turns into llvm.memcpy. This is almost valid per
1843 // C99 6.5.16.1p3, which states "If the value being stored in an object is
1844 // read from another object that overlaps in anyway the storage of the first
1845 // object, then the overlap shall be exact and the two objects shall have
1846 // qualified or unqualified versions of a compatible type."
1848 // memcpy is not defined if the source and destination pointers are exactly
1849 // equal, but other compilers do this optimization, and almost every memcpy
1850 // implementation handles this case safely. If there is a libc that does not
1851 // safely handle this, we can add a target hook.
1853 // Get data size info for this aggregate. Don't copy the tail padding if this
1854 // might be a potentially-overlapping subobject, since the tail padding might
1855 // be occupied by a different object. Otherwise, copying it is fine.
1856 std::pair<CharUnits, CharUnits> TypeInfo;
1858 TypeInfo = getContext().getTypeInfoDataSizeInChars(Ty);
1860 TypeInfo = getContext().getTypeInfoInChars(Ty);
1862 llvm::Value *SizeVal = nullptr;
1863 if (TypeInfo.first.isZero()) {
1864 // But note that getTypeInfo returns 0 for a VLA.
1865 if (auto *VAT = dyn_cast_or_null<VariableArrayType>(
1866 getContext().getAsArrayType(Ty))) {
1868 SizeVal = emitArrayLength(VAT, BaseEltTy, DestPtr);
1869 TypeInfo = getContext().getTypeInfoInChars(BaseEltTy);
1870 assert(!TypeInfo.first.isZero());
1871 SizeVal = Builder.CreateNUWMul(
1873 llvm::ConstantInt::get(SizeTy, TypeInfo.first.getQuantity()));
1877 SizeVal = llvm::ConstantInt::get(SizeTy, TypeInfo.first.getQuantity());
1880 // FIXME: If we have a volatile struct, the optimizer can remove what might
1881 // appear to be `extra' memory ops:
1883 // volatile struct { int i; } a, b;
1890 // we need to use a different call here. We use isVolatile to indicate when
1891 // either the source or the destination is volatile.
1893 DestPtr = Builder.CreateElementBitCast(DestPtr, Int8Ty);
1894 SrcPtr = Builder.CreateElementBitCast(SrcPtr, Int8Ty);
1896 // Don't do any of the memmove_collectable tests if GC isn't set.
1897 if (CGM.getLangOpts().getGC() == LangOptions::NonGC) {
1899 } else if (const RecordType *RecordTy = Ty->getAs<RecordType>()) {
1900 RecordDecl *Record = RecordTy->getDecl();
1901 if (Record->hasObjectMember()) {
1902 CGM.getObjCRuntime().EmitGCMemmoveCollectable(*this, DestPtr, SrcPtr,
1906 } else if (Ty->isArrayType()) {
1907 QualType BaseType = getContext().getBaseElementType(Ty);
1908 if (const RecordType *RecordTy = BaseType->getAs<RecordType>()) {
1909 if (RecordTy->getDecl()->hasObjectMember()) {
1910 CGM.getObjCRuntime().EmitGCMemmoveCollectable(*this, DestPtr, SrcPtr,
1917 auto Inst = Builder.CreateMemCpy(DestPtr, SrcPtr, SizeVal, isVolatile);
1919 // Determine the metadata to describe the position of any padding in this
1920 // memcpy, as well as the TBAA tags for the members of the struct, in case
1921 // the optimizer wishes to expand it in to scalar memory operations.
1922 if (llvm::MDNode *TBAAStructTag = CGM.getTBAAStructInfo(Ty))
1923 Inst->setMetadata(llvm::LLVMContext::MD_tbaa_struct, TBAAStructTag);
1925 if (CGM.getCodeGenOpts().NewStructPathTBAA) {
1926 TBAAAccessInfo TBAAInfo = CGM.mergeTBAAInfoForMemoryTransfer(
1927 Dest.getTBAAInfo(), Src.getTBAAInfo());
1928 CGM.DecorateInstructionWithTBAA(Inst, TBAAInfo);