1 //===--- CGExprAgg.cpp - Emit LLVM Code from Aggregate Expressions --------===//
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
7 //===----------------------------------------------------------------------===//
9 // This contains code to emit Aggregate Expr nodes as LLVM code.
11 //===----------------------------------------------------------------------===//
14 #include "CGObjCRuntime.h"
15 #include "CodeGenFunction.h"
16 #include "CodeGenModule.h"
17 #include "ConstantEmitter.h"
18 #include "TargetInfo.h"
19 #include "clang/AST/ASTContext.h"
20 #include "clang/AST/Attr.h"
21 #include "clang/AST/DeclCXX.h"
22 #include "clang/AST/DeclTemplate.h"
23 #include "clang/AST/StmtVisitor.h"
24 #include "llvm/IR/Constants.h"
25 #include "llvm/IR/Function.h"
26 #include "llvm/IR/GlobalVariable.h"
27 #include "llvm/IR/IntrinsicInst.h"
28 #include "llvm/IR/Intrinsics.h"
29 using namespace clang;
30 using namespace CodeGen;
32 //===----------------------------------------------------------------------===//
33 // Aggregate Expression Emitter
34 //===----------------------------------------------------------------------===//
37 class AggExprEmitter : public StmtVisitor<AggExprEmitter> {
43 AggValueSlot EnsureSlot(QualType T) {
44 if (!Dest.isIgnored()) return Dest;
45 return CGF.CreateAggTemp(T, "agg.tmp.ensured");
47 void EnsureDest(QualType T) {
48 if (!Dest.isIgnored()) return;
49 Dest = CGF.CreateAggTemp(T, "agg.tmp.ensured");
52 // Calls `Fn` with a valid return value slot, potentially creating a temporary
53 // to do so. If a temporary is created, an appropriate copy into `Dest` will
54 // be emitted, as will lifetime markers.
56 // The given function should take a ReturnValueSlot, and return an RValue that
57 // points to said slot.
58 void withReturnValueSlot(const Expr *E,
59 llvm::function_ref<RValue(ReturnValueSlot)> Fn);
62 AggExprEmitter(CodeGenFunction &cgf, AggValueSlot Dest, bool IsResultUnused)
63 : CGF(cgf), Builder(CGF.Builder), Dest(Dest),
64 IsResultUnused(IsResultUnused) { }
66 //===--------------------------------------------------------------------===//
68 //===--------------------------------------------------------------------===//
70 /// EmitAggLoadOfLValue - Given an expression with aggregate type that
71 /// represents a value lvalue, this method emits the address of the lvalue,
72 /// then loads the result into DestPtr.
73 void EmitAggLoadOfLValue(const Expr *E);
80 /// EmitFinalDestCopy - Perform the final copy to DestPtr, if desired.
81 /// SrcIsRValue is true if source comes from an RValue.
82 void EmitFinalDestCopy(QualType type, const LValue &src,
83 ExprValueKind SrcValueKind = EVK_NonRValue);
84 void EmitFinalDestCopy(QualType type, RValue src);
85 void EmitCopy(QualType type, const AggValueSlot &dest,
86 const AggValueSlot &src);
88 void EmitMoveFromReturnSlot(const Expr *E, RValue Src);
90 void EmitArrayInit(Address DestPtr, llvm::ArrayType *AType,
91 QualType ArrayQTy, InitListExpr *E);
93 AggValueSlot::NeedsGCBarriers_t needsGC(QualType T) {
94 if (CGF.getLangOpts().getGC() && TypeRequiresGCollection(T))
95 return AggValueSlot::NeedsGCBarriers;
96 return AggValueSlot::DoesNotNeedGCBarriers;
99 bool TypeRequiresGCollection(QualType T);
101 //===--------------------------------------------------------------------===//
103 //===--------------------------------------------------------------------===//
105 void Visit(Expr *E) {
106 ApplyDebugLocation DL(CGF, E);
107 StmtVisitor<AggExprEmitter>::Visit(E);
110 void VisitStmt(Stmt *S) {
111 CGF.ErrorUnsupported(S, "aggregate expression");
113 void VisitParenExpr(ParenExpr *PE) { Visit(PE->getSubExpr()); }
114 void VisitGenericSelectionExpr(GenericSelectionExpr *GE) {
115 Visit(GE->getResultExpr());
117 void VisitCoawaitExpr(CoawaitExpr *E) {
118 CGF.EmitCoawaitExpr(*E, Dest, IsResultUnused);
120 void VisitCoyieldExpr(CoyieldExpr *E) {
121 CGF.EmitCoyieldExpr(*E, Dest, IsResultUnused);
123 void VisitUnaryCoawait(UnaryOperator *E) { Visit(E->getSubExpr()); }
124 void VisitUnaryExtension(UnaryOperator *E) { Visit(E->getSubExpr()); }
125 void VisitSubstNonTypeTemplateParmExpr(SubstNonTypeTemplateParmExpr *E) {
126 return Visit(E->getReplacement());
129 void VisitConstantExpr(ConstantExpr *E) {
130 if (llvm::Value *Result = ConstantEmitter(CGF).tryEmitConstantExpr(E)) {
131 CGF.EmitAggregateStore(Result, Dest.getAddress(),
132 E->getType().isVolatileQualified());
135 return Visit(E->getSubExpr());
139 void VisitDeclRefExpr(DeclRefExpr *E) { EmitAggLoadOfLValue(E); }
140 void VisitMemberExpr(MemberExpr *ME) { EmitAggLoadOfLValue(ME); }
141 void VisitUnaryDeref(UnaryOperator *E) { EmitAggLoadOfLValue(E); }
142 void VisitStringLiteral(StringLiteral *E) { EmitAggLoadOfLValue(E); }
143 void VisitCompoundLiteralExpr(CompoundLiteralExpr *E);
144 void VisitArraySubscriptExpr(ArraySubscriptExpr *E) {
145 EmitAggLoadOfLValue(E);
147 void VisitPredefinedExpr(const PredefinedExpr *E) {
148 EmitAggLoadOfLValue(E);
152 void VisitCastExpr(CastExpr *E);
153 void VisitCallExpr(const CallExpr *E);
154 void VisitStmtExpr(const StmtExpr *E);
155 void VisitBinaryOperator(const BinaryOperator *BO);
156 void VisitPointerToDataMemberBinaryOperator(const BinaryOperator *BO);
157 void VisitBinAssign(const BinaryOperator *E);
158 void VisitBinComma(const BinaryOperator *E);
159 void VisitBinCmp(const BinaryOperator *E);
160 void VisitCXXRewrittenBinaryOperator(CXXRewrittenBinaryOperator *E) {
161 Visit(E->getSemanticForm());
164 void VisitObjCMessageExpr(ObjCMessageExpr *E);
165 void VisitObjCIvarRefExpr(ObjCIvarRefExpr *E) {
166 EmitAggLoadOfLValue(E);
169 void VisitDesignatedInitUpdateExpr(DesignatedInitUpdateExpr *E);
170 void VisitAbstractConditionalOperator(const AbstractConditionalOperator *CO);
171 void VisitChooseExpr(const ChooseExpr *CE);
172 void VisitInitListExpr(InitListExpr *E);
173 void VisitArrayInitLoopExpr(const ArrayInitLoopExpr *E,
174 llvm::Value *outerBegin = nullptr);
175 void VisitImplicitValueInitExpr(ImplicitValueInitExpr *E);
176 void VisitNoInitExpr(NoInitExpr *E) { } // Do nothing.
177 void VisitCXXDefaultArgExpr(CXXDefaultArgExpr *DAE) {
178 CodeGenFunction::CXXDefaultArgExprScope Scope(CGF, DAE);
179 Visit(DAE->getExpr());
181 void VisitCXXDefaultInitExpr(CXXDefaultInitExpr *DIE) {
182 CodeGenFunction::CXXDefaultInitExprScope Scope(CGF, DIE);
183 Visit(DIE->getExpr());
185 void VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E);
186 void VisitCXXConstructExpr(const CXXConstructExpr *E);
187 void VisitCXXInheritedCtorInitExpr(const CXXInheritedCtorInitExpr *E);
188 void VisitLambdaExpr(LambdaExpr *E);
189 void VisitCXXStdInitializerListExpr(CXXStdInitializerListExpr *E);
190 void VisitExprWithCleanups(ExprWithCleanups *E);
191 void VisitCXXScalarValueInitExpr(CXXScalarValueInitExpr *E);
192 void VisitCXXTypeidExpr(CXXTypeidExpr *E) { EmitAggLoadOfLValue(E); }
193 void VisitMaterializeTemporaryExpr(MaterializeTemporaryExpr *E);
194 void VisitOpaqueValueExpr(OpaqueValueExpr *E);
196 void VisitPseudoObjectExpr(PseudoObjectExpr *E) {
197 if (E->isGLValue()) {
198 LValue LV = CGF.EmitPseudoObjectLValue(E);
199 return EmitFinalDestCopy(E->getType(), LV);
202 CGF.EmitPseudoObjectRValue(E, EnsureSlot(E->getType()));
205 void VisitVAArgExpr(VAArgExpr *E);
207 void EmitInitializationToLValue(Expr *E, LValue Address);
208 void EmitNullInitializationToLValue(LValue Address);
209 // case Expr::ChooseExprClass:
210 void VisitCXXThrowExpr(const CXXThrowExpr *E) { CGF.EmitCXXThrowExpr(E); }
211 void VisitAtomicExpr(AtomicExpr *E) {
212 RValue Res = CGF.EmitAtomicExpr(E);
213 EmitFinalDestCopy(E->getType(), Res);
216 } // end anonymous namespace.
218 //===----------------------------------------------------------------------===//
220 //===----------------------------------------------------------------------===//
222 /// EmitAggLoadOfLValue - Given an expression with aggregate type that
223 /// represents a value lvalue, this method emits the address of the lvalue,
224 /// then loads the result into DestPtr.
225 void AggExprEmitter::EmitAggLoadOfLValue(const Expr *E) {
226 LValue LV = CGF.EmitLValue(E);
228 // If the type of the l-value is atomic, then do an atomic load.
229 if (LV.getType()->isAtomicType() || CGF.LValueIsSuitableForInlineAtomic(LV)) {
230 CGF.EmitAtomicLoad(LV, E->getExprLoc(), Dest);
234 EmitFinalDestCopy(E->getType(), LV);
237 /// True if the given aggregate type requires special GC API calls.
238 bool AggExprEmitter::TypeRequiresGCollection(QualType T) {
239 // Only record types have members that might require garbage collection.
240 const RecordType *RecordTy = T->getAs<RecordType>();
241 if (!RecordTy) return false;
243 // Don't mess with non-trivial C++ types.
244 RecordDecl *Record = RecordTy->getDecl();
245 if (isa<CXXRecordDecl>(Record) &&
246 (cast<CXXRecordDecl>(Record)->hasNonTrivialCopyConstructor() ||
247 !cast<CXXRecordDecl>(Record)->hasTrivialDestructor()))
250 // Check whether the type has an object member.
251 return Record->hasObjectMember();
254 void AggExprEmitter::withReturnValueSlot(
255 const Expr *E, llvm::function_ref<RValue(ReturnValueSlot)> EmitCall) {
256 QualType RetTy = E->getType();
257 bool RequiresDestruction =
258 !Dest.isExternallyDestructed() &&
259 RetTy.isDestructedType() == QualType::DK_nontrivial_c_struct;
261 // If it makes no observable difference, save a memcpy + temporary.
263 // We need to always provide our own temporary if destruction is required.
264 // Otherwise, EmitCall will emit its own, notice that it's "unused", and end
265 // its lifetime before we have the chance to emit a proper destructor call.
266 bool UseTemp = Dest.isPotentiallyAliased() || Dest.requiresGCollection() ||
267 (RequiresDestruction && !Dest.getAddress().isValid());
269 Address RetAddr = Address::invalid();
270 Address RetAllocaAddr = Address::invalid();
272 EHScopeStack::stable_iterator LifetimeEndBlock;
273 llvm::Value *LifetimeSizePtr = nullptr;
274 llvm::IntrinsicInst *LifetimeStartInst = nullptr;
276 RetAddr = Dest.getAddress();
278 RetAddr = CGF.CreateMemTemp(RetTy, "tmp", &RetAllocaAddr);
280 CGF.CGM.getDataLayout().getTypeAllocSize(CGF.ConvertTypeForMem(RetTy));
281 LifetimeSizePtr = CGF.EmitLifetimeStart(Size, RetAllocaAddr.getPointer());
282 if (LifetimeSizePtr) {
284 cast<llvm::IntrinsicInst>(std::prev(Builder.GetInsertPoint()));
285 assert(LifetimeStartInst->getIntrinsicID() ==
286 llvm::Intrinsic::lifetime_start &&
287 "Last insertion wasn't a lifetime.start?");
289 CGF.pushFullExprCleanup<CodeGenFunction::CallLifetimeEnd>(
290 NormalEHLifetimeMarker, RetAllocaAddr, LifetimeSizePtr);
291 LifetimeEndBlock = CGF.EHStack.stable_begin();
296 EmitCall(ReturnValueSlot(RetAddr, Dest.isVolatile(), IsResultUnused,
297 Dest.isExternallyDestructed()));
302 assert(Dest.getPointer() != Src.getAggregatePointer());
303 EmitFinalDestCopy(E->getType(), Src);
305 if (!RequiresDestruction && LifetimeStartInst) {
306 // If there's no dtor to run, the copy was the last use of our temporary.
307 // Since we're not guaranteed to be in an ExprWithCleanups, clean up
309 CGF.DeactivateCleanupBlock(LifetimeEndBlock, LifetimeStartInst);
310 CGF.EmitLifetimeEnd(LifetimeSizePtr, RetAllocaAddr.getPointer());
314 /// EmitFinalDestCopy - Perform the final copy to DestPtr, if desired.
315 void AggExprEmitter::EmitFinalDestCopy(QualType type, RValue src) {
316 assert(src.isAggregate() && "value must be aggregate value!");
317 LValue srcLV = CGF.MakeAddrLValue(src.getAggregateAddress(), type);
318 EmitFinalDestCopy(type, srcLV, EVK_RValue);
321 /// EmitFinalDestCopy - Perform the final copy to DestPtr, if desired.
322 void AggExprEmitter::EmitFinalDestCopy(QualType type, const LValue &src,
323 ExprValueKind SrcValueKind) {
324 // If Dest is ignored, then we're evaluating an aggregate expression
325 // in a context that doesn't care about the result. Note that loads
326 // from volatile l-values force the existence of a non-ignored
328 if (Dest.isIgnored())
331 // Copy non-trivial C structs here.
332 LValue DstLV = CGF.MakeAddrLValue(
333 Dest.getAddress(), Dest.isVolatile() ? type.withVolatile() : type);
335 if (SrcValueKind == EVK_RValue) {
336 if (type.isNonTrivialToPrimitiveDestructiveMove() == QualType::PCK_Struct) {
337 if (Dest.isPotentiallyAliased())
338 CGF.callCStructMoveAssignmentOperator(DstLV, src);
340 CGF.callCStructMoveConstructor(DstLV, src);
344 if (type.isNonTrivialToPrimitiveCopy() == QualType::PCK_Struct) {
345 if (Dest.isPotentiallyAliased())
346 CGF.callCStructCopyAssignmentOperator(DstLV, src);
348 CGF.callCStructCopyConstructor(DstLV, src);
353 AggValueSlot srcAgg = AggValueSlot::forLValue(
354 src, CGF, AggValueSlot::IsDestructed, needsGC(type),
355 AggValueSlot::IsAliased, AggValueSlot::MayOverlap);
356 EmitCopy(type, Dest, srcAgg);
359 /// Perform a copy from the source into the destination.
361 /// \param type - the type of the aggregate being copied; qualifiers are
363 void AggExprEmitter::EmitCopy(QualType type, const AggValueSlot &dest,
364 const AggValueSlot &src) {
365 if (dest.requiresGCollection()) {
366 CharUnits sz = dest.getPreferredSize(CGF.getContext(), type);
367 llvm::Value *size = llvm::ConstantInt::get(CGF.SizeTy, sz.getQuantity());
368 CGF.CGM.getObjCRuntime().EmitGCMemmoveCollectable(CGF,
375 // If the result of the assignment is used, copy the LHS there also.
376 // It's volatile if either side is. Use the minimum alignment of
378 LValue DestLV = CGF.MakeAddrLValue(dest.getAddress(), type);
379 LValue SrcLV = CGF.MakeAddrLValue(src.getAddress(), type);
380 CGF.EmitAggregateCopy(DestLV, SrcLV, type, dest.mayOverlap(),
381 dest.isVolatile() || src.isVolatile());
384 /// Emit the initializer for a std::initializer_list initialized with a
385 /// real initializer list.
387 AggExprEmitter::VisitCXXStdInitializerListExpr(CXXStdInitializerListExpr *E) {
388 // Emit an array containing the elements. The array is externally destructed
389 // if the std::initializer_list object is.
390 ASTContext &Ctx = CGF.getContext();
391 LValue Array = CGF.EmitLValue(E->getSubExpr());
392 assert(Array.isSimple() && "initializer_list array not a simple lvalue");
393 Address ArrayPtr = Array.getAddress(CGF);
395 const ConstantArrayType *ArrayType =
396 Ctx.getAsConstantArrayType(E->getSubExpr()->getType());
397 assert(ArrayType && "std::initializer_list constructed from non-array");
399 // FIXME: Perform the checks on the field types in SemaInit.
400 RecordDecl *Record = E->getType()->castAs<RecordType>()->getDecl();
401 RecordDecl::field_iterator Field = Record->field_begin();
402 if (Field == Record->field_end()) {
403 CGF.ErrorUnsupported(E, "weird std::initializer_list");
408 if (!Field->getType()->isPointerType() ||
409 !Ctx.hasSameType(Field->getType()->getPointeeType(),
410 ArrayType->getElementType())) {
411 CGF.ErrorUnsupported(E, "weird std::initializer_list");
415 AggValueSlot Dest = EnsureSlot(E->getType());
416 LValue DestLV = CGF.MakeAddrLValue(Dest.getAddress(), E->getType());
417 LValue Start = CGF.EmitLValueForFieldInitialization(DestLV, *Field);
418 llvm::Value *Zero = llvm::ConstantInt::get(CGF.PtrDiffTy, 0);
419 llvm::Value *IdxStart[] = { Zero, Zero };
420 llvm::Value *ArrayStart =
421 Builder.CreateInBoundsGEP(ArrayPtr.getPointer(), IdxStart, "arraystart");
422 CGF.EmitStoreThroughLValue(RValue::get(ArrayStart), Start);
425 if (Field == Record->field_end()) {
426 CGF.ErrorUnsupported(E, "weird std::initializer_list");
430 llvm::Value *Size = Builder.getInt(ArrayType->getSize());
431 LValue EndOrLength = CGF.EmitLValueForFieldInitialization(DestLV, *Field);
432 if (Field->getType()->isPointerType() &&
433 Ctx.hasSameType(Field->getType()->getPointeeType(),
434 ArrayType->getElementType())) {
436 llvm::Value *IdxEnd[] = { Zero, Size };
437 llvm::Value *ArrayEnd =
438 Builder.CreateInBoundsGEP(ArrayPtr.getPointer(), IdxEnd, "arrayend");
439 CGF.EmitStoreThroughLValue(RValue::get(ArrayEnd), EndOrLength);
440 } else if (Ctx.hasSameType(Field->getType(), Ctx.getSizeType())) {
442 CGF.EmitStoreThroughLValue(RValue::get(Size), EndOrLength);
444 CGF.ErrorUnsupported(E, "weird std::initializer_list");
449 /// Determine if E is a trivial array filler, that is, one that is
450 /// equivalent to zero-initialization.
451 static bool isTrivialFiller(Expr *E) {
455 if (isa<ImplicitValueInitExpr>(E))
458 if (auto *ILE = dyn_cast<InitListExpr>(E)) {
459 if (ILE->getNumInits())
461 return isTrivialFiller(ILE->getArrayFiller());
464 if (auto *Cons = dyn_cast_or_null<CXXConstructExpr>(E))
465 return Cons->getConstructor()->isDefaultConstructor() &&
466 Cons->getConstructor()->isTrivial();
468 // FIXME: Are there other cases where we can avoid emitting an initializer?
472 /// Emit initialization of an array from an initializer list.
473 void AggExprEmitter::EmitArrayInit(Address DestPtr, llvm::ArrayType *AType,
474 QualType ArrayQTy, InitListExpr *E) {
475 uint64_t NumInitElements = E->getNumInits();
477 uint64_t NumArrayElements = AType->getNumElements();
478 assert(NumInitElements <= NumArrayElements);
480 QualType elementType =
481 CGF.getContext().getAsArrayType(ArrayQTy)->getElementType();
483 // DestPtr is an array*. Construct an elementType* by drilling
485 llvm::Value *zero = llvm::ConstantInt::get(CGF.SizeTy, 0);
486 llvm::Value *indices[] = { zero, zero };
488 Builder.CreateInBoundsGEP(DestPtr.getPointer(), indices, "arrayinit.begin");
490 CharUnits elementSize = CGF.getContext().getTypeSizeInChars(elementType);
491 CharUnits elementAlign =
492 DestPtr.getAlignment().alignmentOfArrayElement(elementSize);
494 // Consider initializing the array by copying from a global. For this to be
495 // more efficient than per-element initialization, the size of the elements
496 // with explicit initializers should be large enough.
497 if (NumInitElements * elementSize.getQuantity() > 16 &&
498 elementType.isTriviallyCopyableType(CGF.getContext())) {
499 CodeGen::CodeGenModule &CGM = CGF.CGM;
500 ConstantEmitter Emitter(CGF);
501 LangAS AS = ArrayQTy.getAddressSpace();
502 if (llvm::Constant *C = Emitter.tryEmitForInitializer(E, AS, ArrayQTy)) {
503 auto GV = new llvm::GlobalVariable(
504 CGM.getModule(), C->getType(),
505 CGM.isTypeConstant(ArrayQTy, /* ExcludeCtorDtor= */ true),
506 llvm::GlobalValue::PrivateLinkage, C, "constinit",
507 /* InsertBefore= */ nullptr, llvm::GlobalVariable::NotThreadLocal,
508 CGM.getContext().getTargetAddressSpace(AS));
509 Emitter.finalize(GV);
510 CharUnits Align = CGM.getContext().getTypeAlignInChars(ArrayQTy);
511 GV->setAlignment(Align.getAsAlign());
512 EmitFinalDestCopy(ArrayQTy, CGF.MakeAddrLValue(GV, ArrayQTy, Align));
517 // Exception safety requires us to destroy all the
518 // already-constructed members if an initializer throws.
519 // For that, we'll need an EH cleanup.
520 QualType::DestructionKind dtorKind = elementType.isDestructedType();
521 Address endOfInit = Address::invalid();
522 EHScopeStack::stable_iterator cleanup;
523 llvm::Instruction *cleanupDominator = nullptr;
524 if (CGF.needsEHCleanup(dtorKind)) {
525 // In principle we could tell the cleanup where we are more
526 // directly, but the control flow can get so varied here that it
527 // would actually be quite complex. Therefore we go through an
529 endOfInit = CGF.CreateTempAlloca(begin->getType(), CGF.getPointerAlign(),
530 "arrayinit.endOfInit");
531 cleanupDominator = Builder.CreateStore(begin, endOfInit);
532 CGF.pushIrregularPartialArrayCleanup(begin, endOfInit, elementType,
534 CGF.getDestroyer(dtorKind));
535 cleanup = CGF.EHStack.stable_begin();
537 // Otherwise, remember that we didn't need a cleanup.
539 dtorKind = QualType::DK_none;
542 llvm::Value *one = llvm::ConstantInt::get(CGF.SizeTy, 1);
544 // The 'current element to initialize'. The invariants on this
545 // variable are complicated. Essentially, after each iteration of
546 // the loop, it points to the last initialized element, except
547 // that it points to the beginning of the array before any
548 // elements have been initialized.
549 llvm::Value *element = begin;
551 // Emit the explicit initializers.
552 for (uint64_t i = 0; i != NumInitElements; ++i) {
553 // Advance to the next element.
555 element = Builder.CreateInBoundsGEP(element, one, "arrayinit.element");
557 // Tell the cleanup that it needs to destroy up to this
558 // element. TODO: some of these stores can be trivially
559 // observed to be unnecessary.
560 if (endOfInit.isValid()) Builder.CreateStore(element, endOfInit);
564 CGF.MakeAddrLValue(Address(element, elementAlign), elementType);
565 EmitInitializationToLValue(E->getInit(i), elementLV);
568 // Check whether there's a non-trivial array-fill expression.
569 Expr *filler = E->getArrayFiller();
570 bool hasTrivialFiller = isTrivialFiller(filler);
572 // Any remaining elements need to be zero-initialized, possibly
573 // using the filler expression. We can skip this if the we're
574 // emitting to zeroed memory.
575 if (NumInitElements != NumArrayElements &&
576 !(Dest.isZeroed() && hasTrivialFiller &&
577 CGF.getTypes().isZeroInitializable(elementType))) {
579 // Use an actual loop. This is basically
580 // do { *array++ = filler; } while (array != end);
582 // Advance to the start of the rest of the array.
583 if (NumInitElements) {
584 element = Builder.CreateInBoundsGEP(element, one, "arrayinit.start");
585 if (endOfInit.isValid()) Builder.CreateStore(element, endOfInit);
588 // Compute the end of the array.
589 llvm::Value *end = Builder.CreateInBoundsGEP(begin,
590 llvm::ConstantInt::get(CGF.SizeTy, NumArrayElements),
593 llvm::BasicBlock *entryBB = Builder.GetInsertBlock();
594 llvm::BasicBlock *bodyBB = CGF.createBasicBlock("arrayinit.body");
596 // Jump into the body.
597 CGF.EmitBlock(bodyBB);
598 llvm::PHINode *currentElement =
599 Builder.CreatePHI(element->getType(), 2, "arrayinit.cur");
600 currentElement->addIncoming(element, entryBB);
602 // Emit the actual filler expression.
604 // C++1z [class.temporary]p5:
605 // when a default constructor is called to initialize an element of
606 // an array with no corresponding initializer [...] the destruction of
607 // every temporary created in a default argument is sequenced before
608 // the construction of the next array element, if any
609 CodeGenFunction::RunCleanupsScope CleanupsScope(CGF);
611 CGF.MakeAddrLValue(Address(currentElement, elementAlign), elementType);
613 EmitInitializationToLValue(filler, elementLV);
615 EmitNullInitializationToLValue(elementLV);
618 // Move on to the next element.
619 llvm::Value *nextElement =
620 Builder.CreateInBoundsGEP(currentElement, one, "arrayinit.next");
622 // Tell the EH cleanup that we finished with the last element.
623 if (endOfInit.isValid()) Builder.CreateStore(nextElement, endOfInit);
625 // Leave the loop if we're done.
626 llvm::Value *done = Builder.CreateICmpEQ(nextElement, end,
628 llvm::BasicBlock *endBB = CGF.createBasicBlock("arrayinit.end");
629 Builder.CreateCondBr(done, endBB, bodyBB);
630 currentElement->addIncoming(nextElement, Builder.GetInsertBlock());
632 CGF.EmitBlock(endBB);
635 // Leave the partial-array cleanup if we entered one.
636 if (dtorKind) CGF.DeactivateCleanupBlock(cleanup, cleanupDominator);
639 //===----------------------------------------------------------------------===//
641 //===----------------------------------------------------------------------===//
643 void AggExprEmitter::VisitMaterializeTemporaryExpr(MaterializeTemporaryExpr *E){
644 Visit(E->getSubExpr());
647 void AggExprEmitter::VisitOpaqueValueExpr(OpaqueValueExpr *e) {
648 // If this is a unique OVE, just visit its source expression.
650 Visit(e->getSourceExpr());
652 EmitFinalDestCopy(e->getType(), CGF.getOrCreateOpaqueLValueMapping(e));
656 AggExprEmitter::VisitCompoundLiteralExpr(CompoundLiteralExpr *E) {
657 if (Dest.isPotentiallyAliased() &&
658 E->getType().isPODType(CGF.getContext())) {
659 // For a POD type, just emit a load of the lvalue + a copy, because our
660 // compound literal might alias the destination.
661 EmitAggLoadOfLValue(E);
665 AggValueSlot Slot = EnsureSlot(E->getType());
667 // Block-scope compound literals are destroyed at the end of the enclosing
670 !CGF.getLangOpts().CPlusPlus && !Slot.isExternallyDestructed();
672 Slot.setExternallyDestructed();
674 CGF.EmitAggExpr(E->getInitializer(), Slot);
677 if (QualType::DestructionKind DtorKind = E->getType().isDestructedType())
678 CGF.pushLifetimeExtendedDestroy(
679 CGF.getCleanupKind(DtorKind), Slot.getAddress(), E->getType(),
680 CGF.getDestroyer(DtorKind), DtorKind & EHCleanup);
683 /// Attempt to look through various unimportant expressions to find a
684 /// cast of the given kind.
685 static Expr *findPeephole(Expr *op, CastKind kind, const ASTContext &ctx) {
686 op = op->IgnoreParenNoopCasts(ctx);
687 if (auto castE = dyn_cast<CastExpr>(op)) {
688 if (castE->getCastKind() == kind)
689 return castE->getSubExpr();
694 void AggExprEmitter::VisitCastExpr(CastExpr *E) {
695 if (const auto *ECE = dyn_cast<ExplicitCastExpr>(E))
696 CGF.CGM.EmitExplicitCastExprType(ECE, &CGF);
697 switch (E->getCastKind()) {
699 // FIXME: Can this actually happen? We have no test coverage for it.
700 assert(isa<CXXDynamicCastExpr>(E) && "CK_Dynamic without a dynamic_cast?");
701 LValue LV = CGF.EmitCheckedLValue(E->getSubExpr(),
702 CodeGenFunction::TCK_Load);
703 // FIXME: Do we also need to handle property references here?
705 CGF.EmitDynamicCast(LV.getAddress(CGF), cast<CXXDynamicCastExpr>(E));
707 CGF.CGM.ErrorUnsupported(E, "non-simple lvalue dynamic_cast");
709 if (!Dest.isIgnored())
710 CGF.CGM.ErrorUnsupported(E, "lvalue dynamic_cast with a destination");
715 // Evaluate even if the destination is ignored.
716 if (Dest.isIgnored()) {
717 CGF.EmitAnyExpr(E->getSubExpr(), AggValueSlot::ignored(),
718 /*ignoreResult=*/true);
722 // GCC union extension
723 QualType Ty = E->getSubExpr()->getType();
725 Builder.CreateElementBitCast(Dest.getAddress(), CGF.ConvertType(Ty));
726 EmitInitializationToLValue(E->getSubExpr(),
727 CGF.MakeAddrLValue(CastPtr, Ty));
731 case CK_LValueToRValueBitCast: {
732 if (Dest.isIgnored()) {
733 CGF.EmitAnyExpr(E->getSubExpr(), AggValueSlot::ignored(),
734 /*ignoreResult=*/true);
738 LValue SourceLV = CGF.EmitLValue(E->getSubExpr());
739 Address SourceAddress =
740 Builder.CreateElementBitCast(SourceLV.getAddress(CGF), CGF.Int8Ty);
741 Address DestAddress =
742 Builder.CreateElementBitCast(Dest.getAddress(), CGF.Int8Ty);
743 llvm::Value *SizeVal = llvm::ConstantInt::get(
745 CGF.getContext().getTypeSizeInChars(E->getType()).getQuantity());
746 Builder.CreateMemCpy(DestAddress, SourceAddress, SizeVal);
750 case CK_DerivedToBase:
751 case CK_BaseToDerived:
752 case CK_UncheckedDerivedToBase: {
753 llvm_unreachable("cannot perform hierarchy conversion in EmitAggExpr: "
754 "should have been unpacked before we got here");
757 case CK_NonAtomicToAtomic:
758 case CK_AtomicToNonAtomic: {
759 bool isToAtomic = (E->getCastKind() == CK_NonAtomicToAtomic);
761 // Determine the atomic and value types.
762 QualType atomicType = E->getSubExpr()->getType();
763 QualType valueType = E->getType();
764 if (isToAtomic) std::swap(atomicType, valueType);
766 assert(atomicType->isAtomicType());
767 assert(CGF.getContext().hasSameUnqualifiedType(valueType,
768 atomicType->castAs<AtomicType>()->getValueType()));
770 // Just recurse normally if we're ignoring the result or the
771 // atomic type doesn't change representation.
772 if (Dest.isIgnored() || !CGF.CGM.isPaddedAtomicType(atomicType)) {
773 return Visit(E->getSubExpr());
776 CastKind peepholeTarget =
777 (isToAtomic ? CK_AtomicToNonAtomic : CK_NonAtomicToAtomic);
779 // These two cases are reverses of each other; try to peephole them.
781 findPeephole(E->getSubExpr(), peepholeTarget, CGF.getContext())) {
782 assert(CGF.getContext().hasSameUnqualifiedType(op->getType(),
784 "peephole significantly changed types?");
788 // If we're converting an r-value of non-atomic type to an r-value
789 // of atomic type, just emit directly into the relevant sub-object.
791 AggValueSlot valueDest = Dest;
792 if (!valueDest.isIgnored() && CGF.CGM.isPaddedAtomicType(atomicType)) {
793 // Zero-initialize. (Strictly speaking, we only need to initialize
794 // the padding at the end, but this is simpler.)
795 if (!Dest.isZeroed())
796 CGF.EmitNullInitialization(Dest.getAddress(), atomicType);
798 // Build a GEP to refer to the subobject.
800 CGF.Builder.CreateStructGEP(valueDest.getAddress(), 0);
801 valueDest = AggValueSlot::forAddr(valueAddr,
802 valueDest.getQualifiers(),
803 valueDest.isExternallyDestructed(),
804 valueDest.requiresGCollection(),
805 valueDest.isPotentiallyAliased(),
806 AggValueSlot::DoesNotOverlap,
807 AggValueSlot::IsZeroed);
810 CGF.EmitAggExpr(E->getSubExpr(), valueDest);
814 // Otherwise, we're converting an atomic type to a non-atomic type.
815 // Make an atomic temporary, emit into that, and then copy the value out.
816 AggValueSlot atomicSlot =
817 CGF.CreateAggTemp(atomicType, "atomic-to-nonatomic.temp");
818 CGF.EmitAggExpr(E->getSubExpr(), atomicSlot);
820 Address valueAddr = Builder.CreateStructGEP(atomicSlot.getAddress(), 0);
821 RValue rvalue = RValue::getAggregate(valueAddr, atomicSlot.isVolatile());
822 return EmitFinalDestCopy(valueType, rvalue);
824 case CK_AddressSpaceConversion:
825 return Visit(E->getSubExpr());
827 case CK_LValueToRValue:
828 // If we're loading from a volatile type, force the destination
830 if (E->getSubExpr()->getType().isVolatileQualified()) {
832 !Dest.isExternallyDestructed() &&
833 E->getType().isDestructedType() == QualType::DK_nontrivial_c_struct;
835 Dest.setExternallyDestructed();
836 EnsureDest(E->getType());
837 Visit(E->getSubExpr());
840 CGF.pushDestroy(QualType::DK_nontrivial_c_struct, Dest.getAddress(),
850 case CK_UserDefinedConversion:
851 case CK_ConstructorConversion:
852 assert(CGF.getContext().hasSameUnqualifiedType(E->getSubExpr()->getType(),
854 "Implicit cast types must be compatible");
855 Visit(E->getSubExpr());
858 case CK_LValueBitCast:
859 llvm_unreachable("should not be emitting lvalue bitcast as rvalue");
863 case CK_ArrayToPointerDecay:
864 case CK_FunctionToPointerDecay:
865 case CK_NullToPointer:
866 case CK_NullToMemberPointer:
867 case CK_BaseToDerivedMemberPointer:
868 case CK_DerivedToBaseMemberPointer:
869 case CK_MemberPointerToBoolean:
870 case CK_ReinterpretMemberPointer:
871 case CK_IntegralToPointer:
872 case CK_PointerToIntegral:
873 case CK_PointerToBoolean:
876 case CK_IntegralCast:
877 case CK_BooleanToSignedIntegral:
878 case CK_IntegralToBoolean:
879 case CK_IntegralToFloating:
880 case CK_FloatingToIntegral:
881 case CK_FloatingToBoolean:
882 case CK_FloatingCast:
883 case CK_CPointerToObjCPointerCast:
884 case CK_BlockPointerToObjCPointerCast:
885 case CK_AnyPointerToBlockPointerCast:
886 case CK_ObjCObjectLValueCast:
887 case CK_FloatingRealToComplex:
888 case CK_FloatingComplexToReal:
889 case CK_FloatingComplexToBoolean:
890 case CK_FloatingComplexCast:
891 case CK_FloatingComplexToIntegralComplex:
892 case CK_IntegralRealToComplex:
893 case CK_IntegralComplexToReal:
894 case CK_IntegralComplexToBoolean:
895 case CK_IntegralComplexCast:
896 case CK_IntegralComplexToFloatingComplex:
897 case CK_ARCProduceObject:
898 case CK_ARCConsumeObject:
899 case CK_ARCReclaimReturnedObject:
900 case CK_ARCExtendBlockObject:
901 case CK_CopyAndAutoreleaseBlockObject:
902 case CK_BuiltinFnToFnPtr:
903 case CK_ZeroToOCLOpaqueType:
905 case CK_IntToOCLSampler:
906 case CK_FixedPointCast:
907 case CK_FixedPointToBoolean:
908 case CK_FixedPointToIntegral:
909 case CK_IntegralToFixedPoint:
910 llvm_unreachable("cast kind invalid for aggregate types");
914 void AggExprEmitter::VisitCallExpr(const CallExpr *E) {
915 if (E->getCallReturnType(CGF.getContext())->isReferenceType()) {
916 EmitAggLoadOfLValue(E);
920 withReturnValueSlot(E, [&](ReturnValueSlot Slot) {
921 return CGF.EmitCallExpr(E, Slot);
925 void AggExprEmitter::VisitObjCMessageExpr(ObjCMessageExpr *E) {
926 withReturnValueSlot(E, [&](ReturnValueSlot Slot) {
927 return CGF.EmitObjCMessageExpr(E, Slot);
931 void AggExprEmitter::VisitBinComma(const BinaryOperator *E) {
932 CGF.EmitIgnoredExpr(E->getLHS());
936 void AggExprEmitter::VisitStmtExpr(const StmtExpr *E) {
937 CodeGenFunction::StmtExprEvaluation eval(CGF);
938 CGF.EmitCompoundStmt(*E->getSubStmt(), true, Dest);
947 static llvm::Value *EmitCompare(CGBuilderTy &Builder, CodeGenFunction &CGF,
948 const BinaryOperator *E, llvm::Value *LHS,
949 llvm::Value *RHS, CompareKind Kind,
950 const char *NameSuffix = "") {
951 QualType ArgTy = E->getLHS()->getType();
952 if (const ComplexType *CT = ArgTy->getAs<ComplexType>())
953 ArgTy = CT->getElementType();
955 if (const auto *MPT = ArgTy->getAs<MemberPointerType>()) {
956 assert(Kind == CK_Equal &&
957 "member pointers may only be compared for equality");
958 return CGF.CGM.getCXXABI().EmitMemberPointerComparison(
959 CGF, LHS, RHS, MPT, /*IsInequality*/ false);
962 // Compute the comparison instructions for the specified comparison kind.
965 llvm::CmpInst::Predicate FCmp;
966 llvm::CmpInst::Predicate SCmp;
967 llvm::CmpInst::Predicate UCmp;
969 CmpInstInfo InstInfo = [&]() -> CmpInstInfo {
970 using FI = llvm::FCmpInst;
971 using II = llvm::ICmpInst;
974 return {"cmp.lt", FI::FCMP_OLT, II::ICMP_SLT, II::ICMP_ULT};
976 return {"cmp.gt", FI::FCMP_OGT, II::ICMP_SGT, II::ICMP_UGT};
978 return {"cmp.eq", FI::FCMP_OEQ, II::ICMP_EQ, II::ICMP_EQ};
980 llvm_unreachable("Unrecognised CompareKind enum");
983 if (ArgTy->hasFloatingRepresentation())
984 return Builder.CreateFCmp(InstInfo.FCmp, LHS, RHS,
985 llvm::Twine(InstInfo.Name) + NameSuffix);
986 if (ArgTy->isIntegralOrEnumerationType() || ArgTy->isPointerType()) {
988 ArgTy->hasSignedIntegerRepresentation() ? InstInfo.SCmp : InstInfo.UCmp;
989 return Builder.CreateICmp(Inst, LHS, RHS,
990 llvm::Twine(InstInfo.Name) + NameSuffix);
993 llvm_unreachable("unsupported aggregate binary expression should have "
994 "already been handled");
997 void AggExprEmitter::VisitBinCmp(const BinaryOperator *E) {
998 using llvm::BasicBlock;
1001 assert(CGF.getContext().hasSameType(E->getLHS()->getType(),
1002 E->getRHS()->getType()));
1003 const ComparisonCategoryInfo &CmpInfo =
1004 CGF.getContext().CompCategories.getInfoForType(E->getType());
1005 assert(CmpInfo.Record->isTriviallyCopyable() &&
1006 "cannot copy non-trivially copyable aggregate");
1008 QualType ArgTy = E->getLHS()->getType();
1010 if (!ArgTy->isIntegralOrEnumerationType() && !ArgTy->isRealFloatingType() &&
1011 !ArgTy->isNullPtrType() && !ArgTy->isPointerType() &&
1012 !ArgTy->isMemberPointerType() && !ArgTy->isAnyComplexType()) {
1013 return CGF.ErrorUnsupported(E, "aggregate three-way comparison");
1015 bool IsComplex = ArgTy->isAnyComplexType();
1017 // Evaluate the operands to the expression and extract their values.
1018 auto EmitOperand = [&](Expr *E) -> std::pair<Value *, Value *> {
1019 RValue RV = CGF.EmitAnyExpr(E);
1021 return {RV.getScalarVal(), nullptr};
1022 if (RV.isAggregate())
1023 return {RV.getAggregatePointer(), nullptr};
1024 assert(RV.isComplex());
1025 return RV.getComplexVal();
1027 auto LHSValues = EmitOperand(E->getLHS()),
1028 RHSValues = EmitOperand(E->getRHS());
1030 auto EmitCmp = [&](CompareKind K) {
1031 Value *Cmp = EmitCompare(Builder, CGF, E, LHSValues.first, RHSValues.first,
1032 K, IsComplex ? ".r" : "");
1035 assert(K == CompareKind::CK_Equal);
1036 Value *CmpImag = EmitCompare(Builder, CGF, E, LHSValues.second,
1037 RHSValues.second, K, ".i");
1038 return Builder.CreateAnd(Cmp, CmpImag, "and.eq");
1040 auto EmitCmpRes = [&](const ComparisonCategoryInfo::ValueInfo *VInfo) {
1041 return Builder.getInt(VInfo->getIntValue());
1045 if (ArgTy->isNullPtrType()) {
1046 Select = EmitCmpRes(CmpInfo.getEqualOrEquiv());
1047 } else if (!CmpInfo.isPartial()) {
1049 Builder.CreateSelect(EmitCmp(CK_Less), EmitCmpRes(CmpInfo.getLess()),
1050 EmitCmpRes(CmpInfo.getGreater()), "sel.lt");
1051 Select = Builder.CreateSelect(EmitCmp(CK_Equal),
1052 EmitCmpRes(CmpInfo.getEqualOrEquiv()),
1053 SelectOne, "sel.eq");
1055 Value *SelectEq = Builder.CreateSelect(
1056 EmitCmp(CK_Equal), EmitCmpRes(CmpInfo.getEqualOrEquiv()),
1057 EmitCmpRes(CmpInfo.getUnordered()), "sel.eq");
1058 Value *SelectGT = Builder.CreateSelect(EmitCmp(CK_Greater),
1059 EmitCmpRes(CmpInfo.getGreater()),
1060 SelectEq, "sel.gt");
1061 Select = Builder.CreateSelect(
1062 EmitCmp(CK_Less), EmitCmpRes(CmpInfo.getLess()), SelectGT, "sel.lt");
1064 // Create the return value in the destination slot.
1065 EnsureDest(E->getType());
1066 LValue DestLV = CGF.MakeAddrLValue(Dest.getAddress(), E->getType());
1068 // Emit the address of the first (and only) field in the comparison category
1069 // type, and initialize it from the constant integer value selected above.
1070 LValue FieldLV = CGF.EmitLValueForFieldInitialization(
1071 DestLV, *CmpInfo.Record->field_begin());
1072 CGF.EmitStoreThroughLValue(RValue::get(Select), FieldLV, /*IsInit*/ true);
1074 // All done! The result is in the Dest slot.
1077 void AggExprEmitter::VisitBinaryOperator(const BinaryOperator *E) {
1078 if (E->getOpcode() == BO_PtrMemD || E->getOpcode() == BO_PtrMemI)
1079 VisitPointerToDataMemberBinaryOperator(E);
1081 CGF.ErrorUnsupported(E, "aggregate binary expression");
1084 void AggExprEmitter::VisitPointerToDataMemberBinaryOperator(
1085 const BinaryOperator *E) {
1086 LValue LV = CGF.EmitPointerToDataMemberBinaryExpr(E);
1087 EmitFinalDestCopy(E->getType(), LV);
1090 /// Is the value of the given expression possibly a reference to or
1091 /// into a __block variable?
1092 static bool isBlockVarRef(const Expr *E) {
1093 // Make sure we look through parens.
1094 E = E->IgnoreParens();
1096 // Check for a direct reference to a __block variable.
1097 if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E)) {
1098 const VarDecl *var = dyn_cast<VarDecl>(DRE->getDecl());
1099 return (var && var->hasAttr<BlocksAttr>());
1102 // More complicated stuff.
1104 // Binary operators.
1105 if (const BinaryOperator *op = dyn_cast<BinaryOperator>(E)) {
1106 // For an assignment or pointer-to-member operation, just care
1108 if (op->isAssignmentOp() || op->isPtrMemOp())
1109 return isBlockVarRef(op->getLHS());
1111 // For a comma, just care about the RHS.
1112 if (op->getOpcode() == BO_Comma)
1113 return isBlockVarRef(op->getRHS());
1115 // FIXME: pointer arithmetic?
1118 // Check both sides of a conditional operator.
1119 } else if (const AbstractConditionalOperator *op
1120 = dyn_cast<AbstractConditionalOperator>(E)) {
1121 return isBlockVarRef(op->getTrueExpr())
1122 || isBlockVarRef(op->getFalseExpr());
1124 // OVEs are required to support BinaryConditionalOperators.
1125 } else if (const OpaqueValueExpr *op
1126 = dyn_cast<OpaqueValueExpr>(E)) {
1127 if (const Expr *src = op->getSourceExpr())
1128 return isBlockVarRef(src);
1130 // Casts are necessary to get things like (*(int*)&var) = foo().
1131 // We don't really care about the kind of cast here, except
1132 // we don't want to look through l2r casts, because it's okay
1133 // to get the *value* in a __block variable.
1134 } else if (const CastExpr *cast = dyn_cast<CastExpr>(E)) {
1135 if (cast->getCastKind() == CK_LValueToRValue)
1137 return isBlockVarRef(cast->getSubExpr());
1139 // Handle unary operators. Again, just aggressively look through
1140 // it, ignoring the operation.
1141 } else if (const UnaryOperator *uop = dyn_cast<UnaryOperator>(E)) {
1142 return isBlockVarRef(uop->getSubExpr());
1144 // Look into the base of a field access.
1145 } else if (const MemberExpr *mem = dyn_cast<MemberExpr>(E)) {
1146 return isBlockVarRef(mem->getBase());
1148 // Look into the base of a subscript.
1149 } else if (const ArraySubscriptExpr *sub = dyn_cast<ArraySubscriptExpr>(E)) {
1150 return isBlockVarRef(sub->getBase());
1156 void AggExprEmitter::VisitBinAssign(const BinaryOperator *E) {
1157 // For an assignment to work, the value on the right has
1158 // to be compatible with the value on the left.
1159 assert(CGF.getContext().hasSameUnqualifiedType(E->getLHS()->getType(),
1160 E->getRHS()->getType())
1161 && "Invalid assignment");
1163 // If the LHS might be a __block variable, and the RHS can
1164 // potentially cause a block copy, we need to evaluate the RHS first
1165 // so that the assignment goes the right place.
1166 // This is pretty semantically fragile.
1167 if (isBlockVarRef(E->getLHS()) &&
1168 E->getRHS()->HasSideEffects(CGF.getContext())) {
1169 // Ensure that we have a destination, and evaluate the RHS into that.
1170 EnsureDest(E->getRHS()->getType());
1173 // Now emit the LHS and copy into it.
1174 LValue LHS = CGF.EmitCheckedLValue(E->getLHS(), CodeGenFunction::TCK_Store);
1176 // That copy is an atomic copy if the LHS is atomic.
1177 if (LHS.getType()->isAtomicType() ||
1178 CGF.LValueIsSuitableForInlineAtomic(LHS)) {
1179 CGF.EmitAtomicStore(Dest.asRValue(), LHS, /*isInit*/ false);
1183 EmitCopy(E->getLHS()->getType(),
1184 AggValueSlot::forLValue(LHS, CGF, AggValueSlot::IsDestructed,
1185 needsGC(E->getLHS()->getType()),
1186 AggValueSlot::IsAliased,
1187 AggValueSlot::MayOverlap),
1192 LValue LHS = CGF.EmitLValue(E->getLHS());
1194 // If we have an atomic type, evaluate into the destination and then
1195 // do an atomic copy.
1196 if (LHS.getType()->isAtomicType() ||
1197 CGF.LValueIsSuitableForInlineAtomic(LHS)) {
1198 EnsureDest(E->getRHS()->getType());
1200 CGF.EmitAtomicStore(Dest.asRValue(), LHS, /*isInit*/ false);
1204 // Codegen the RHS so that it stores directly into the LHS.
1205 AggValueSlot LHSSlot = AggValueSlot::forLValue(
1206 LHS, CGF, AggValueSlot::IsDestructed, needsGC(E->getLHS()->getType()),
1207 AggValueSlot::IsAliased, AggValueSlot::MayOverlap);
1208 // A non-volatile aggregate destination might have volatile member.
1209 if (!LHSSlot.isVolatile() &&
1210 CGF.hasVolatileMember(E->getLHS()->getType()))
1211 LHSSlot.setVolatile(true);
1213 CGF.EmitAggExpr(E->getRHS(), LHSSlot);
1215 // Copy into the destination if the assignment isn't ignored.
1216 EmitFinalDestCopy(E->getType(), LHS);
1219 void AggExprEmitter::
1220 VisitAbstractConditionalOperator(const AbstractConditionalOperator *E) {
1221 llvm::BasicBlock *LHSBlock = CGF.createBasicBlock("cond.true");
1222 llvm::BasicBlock *RHSBlock = CGF.createBasicBlock("cond.false");
1223 llvm::BasicBlock *ContBlock = CGF.createBasicBlock("cond.end");
1225 // Bind the common expression if necessary.
1226 CodeGenFunction::OpaqueValueMapping binding(CGF, E);
1228 CodeGenFunction::ConditionalEvaluation eval(CGF);
1229 CGF.EmitBranchOnBoolExpr(E->getCond(), LHSBlock, RHSBlock,
1230 CGF.getProfileCount(E));
1232 // Save whether the destination's lifetime is externally managed.
1233 bool isExternallyDestructed = Dest.isExternallyDestructed();
1236 CGF.EmitBlock(LHSBlock);
1237 CGF.incrementProfileCounter(E);
1238 Visit(E->getTrueExpr());
1241 assert(CGF.HaveInsertPoint() && "expression evaluation ended with no IP!");
1242 CGF.Builder.CreateBr(ContBlock);
1244 // If the result of an agg expression is unused, then the emission
1245 // of the LHS might need to create a destination slot. That's fine
1246 // with us, and we can safely emit the RHS into the same slot, but
1247 // we shouldn't claim that it's already being destructed.
1248 Dest.setExternallyDestructed(isExternallyDestructed);
1251 CGF.EmitBlock(RHSBlock);
1252 Visit(E->getFalseExpr());
1255 CGF.EmitBlock(ContBlock);
1258 void AggExprEmitter::VisitChooseExpr(const ChooseExpr *CE) {
1259 Visit(CE->getChosenSubExpr());
1262 void AggExprEmitter::VisitVAArgExpr(VAArgExpr *VE) {
1263 Address ArgValue = Address::invalid();
1264 Address ArgPtr = CGF.EmitVAArg(VE, ArgValue);
1266 // If EmitVAArg fails, emit an error.
1267 if (!ArgPtr.isValid()) {
1268 CGF.ErrorUnsupported(VE, "aggregate va_arg expression");
1272 EmitFinalDestCopy(VE->getType(), CGF.MakeAddrLValue(ArgPtr, VE->getType()));
1275 void AggExprEmitter::VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E) {
1276 // Ensure that we have a slot, but if we already do, remember
1277 // whether it was externally destructed.
1278 bool wasExternallyDestructed = Dest.isExternallyDestructed();
1279 EnsureDest(E->getType());
1281 // We're going to push a destructor if there isn't already one.
1282 Dest.setExternallyDestructed();
1284 Visit(E->getSubExpr());
1286 // Push that destructor we promised.
1287 if (!wasExternallyDestructed)
1288 CGF.EmitCXXTemporary(E->getTemporary(), E->getType(), Dest.getAddress());
1292 AggExprEmitter::VisitCXXConstructExpr(const CXXConstructExpr *E) {
1293 AggValueSlot Slot = EnsureSlot(E->getType());
1294 CGF.EmitCXXConstructExpr(E, Slot);
1297 void AggExprEmitter::VisitCXXInheritedCtorInitExpr(
1298 const CXXInheritedCtorInitExpr *E) {
1299 AggValueSlot Slot = EnsureSlot(E->getType());
1300 CGF.EmitInheritedCXXConstructorCall(
1301 E->getConstructor(), E->constructsVBase(), Slot.getAddress(),
1302 E->inheritedFromVBase(), E);
1306 AggExprEmitter::VisitLambdaExpr(LambdaExpr *E) {
1307 AggValueSlot Slot = EnsureSlot(E->getType());
1308 LValue SlotLV = CGF.MakeAddrLValue(Slot.getAddress(), E->getType());
1310 // We'll need to enter cleanup scopes in case any of the element
1311 // initializers throws an exception.
1312 SmallVector<EHScopeStack::stable_iterator, 16> Cleanups;
1313 llvm::Instruction *CleanupDominator = nullptr;
1315 CXXRecordDecl::field_iterator CurField = E->getLambdaClass()->field_begin();
1316 for (LambdaExpr::const_capture_init_iterator i = E->capture_init_begin(),
1317 e = E->capture_init_end();
1318 i != e; ++i, ++CurField) {
1319 // Emit initialization
1320 LValue LV = CGF.EmitLValueForFieldInitialization(SlotLV, *CurField);
1321 if (CurField->hasCapturedVLAType()) {
1322 CGF.EmitLambdaVLACapture(CurField->getCapturedVLAType(), LV);
1326 EmitInitializationToLValue(*i, LV);
1328 // Push a destructor if necessary.
1329 if (QualType::DestructionKind DtorKind =
1330 CurField->getType().isDestructedType()) {
1331 assert(LV.isSimple());
1332 if (CGF.needsEHCleanup(DtorKind)) {
1333 if (!CleanupDominator)
1334 CleanupDominator = CGF.Builder.CreateAlignedLoad(
1336 llvm::Constant::getNullValue(CGF.Int8PtrTy),
1337 CharUnits::One()); // placeholder
1339 CGF.pushDestroy(EHCleanup, LV.getAddress(CGF), CurField->getType(),
1340 CGF.getDestroyer(DtorKind), false);
1341 Cleanups.push_back(CGF.EHStack.stable_begin());
1346 // Deactivate all the partial cleanups in reverse order, which
1347 // generally means popping them.
1348 for (unsigned i = Cleanups.size(); i != 0; --i)
1349 CGF.DeactivateCleanupBlock(Cleanups[i-1], CleanupDominator);
1351 // Destroy the placeholder if we made one.
1352 if (CleanupDominator)
1353 CleanupDominator->eraseFromParent();
1356 void AggExprEmitter::VisitExprWithCleanups(ExprWithCleanups *E) {
1357 CodeGenFunction::RunCleanupsScope cleanups(CGF);
1358 Visit(E->getSubExpr());
1361 void AggExprEmitter::VisitCXXScalarValueInitExpr(CXXScalarValueInitExpr *E) {
1362 QualType T = E->getType();
1363 AggValueSlot Slot = EnsureSlot(T);
1364 EmitNullInitializationToLValue(CGF.MakeAddrLValue(Slot.getAddress(), T));
1367 void AggExprEmitter::VisitImplicitValueInitExpr(ImplicitValueInitExpr *E) {
1368 QualType T = E->getType();
1369 AggValueSlot Slot = EnsureSlot(T);
1370 EmitNullInitializationToLValue(CGF.MakeAddrLValue(Slot.getAddress(), T));
1373 /// isSimpleZero - If emitting this value will obviously just cause a store of
1374 /// zero to memory, return true. This can return false if uncertain, so it just
1375 /// handles simple cases.
1376 static bool isSimpleZero(const Expr *E, CodeGenFunction &CGF) {
1377 E = E->IgnoreParens();
1380 if (const IntegerLiteral *IL = dyn_cast<IntegerLiteral>(E))
1381 return IL->getValue() == 0;
1383 if (const FloatingLiteral *FL = dyn_cast<FloatingLiteral>(E))
1384 return FL->getValue().isPosZero();
1386 if ((isa<ImplicitValueInitExpr>(E) || isa<CXXScalarValueInitExpr>(E)) &&
1387 CGF.getTypes().isZeroInitializable(E->getType()))
1389 // (int*)0 - Null pointer expressions.
1390 if (const CastExpr *ICE = dyn_cast<CastExpr>(E))
1391 return ICE->getCastKind() == CK_NullToPointer &&
1392 CGF.getTypes().isPointerZeroInitializable(E->getType()) &&
1393 !E->HasSideEffects(CGF.getContext());
1395 if (const CharacterLiteral *CL = dyn_cast<CharacterLiteral>(E))
1396 return CL->getValue() == 0;
1398 // Otherwise, hard case: conservatively return false.
1404 AggExprEmitter::EmitInitializationToLValue(Expr *E, LValue LV) {
1405 QualType type = LV.getType();
1406 // FIXME: Ignore result?
1407 // FIXME: Are initializers affected by volatile?
1408 if (Dest.isZeroed() && isSimpleZero(E, CGF)) {
1409 // Storing "i32 0" to a zero'd memory location is a noop.
1411 } else if (isa<ImplicitValueInitExpr>(E) || isa<CXXScalarValueInitExpr>(E)) {
1412 return EmitNullInitializationToLValue(LV);
1413 } else if (isa<NoInitExpr>(E)) {
1416 } else if (type->isReferenceType()) {
1417 RValue RV = CGF.EmitReferenceBindingToExpr(E);
1418 return CGF.EmitStoreThroughLValue(RV, LV);
1421 switch (CGF.getEvaluationKind(type)) {
1423 CGF.EmitComplexExprIntoLValue(E, LV, /*isInit*/ true);
1427 E, AggValueSlot::forLValue(LV, CGF, AggValueSlot::IsDestructed,
1428 AggValueSlot::DoesNotNeedGCBarriers,
1429 AggValueSlot::IsNotAliased,
1430 AggValueSlot::MayOverlap, Dest.isZeroed()));
1433 if (LV.isSimple()) {
1434 CGF.EmitScalarInit(E, /*D=*/nullptr, LV, /*Captured=*/false);
1436 CGF.EmitStoreThroughLValue(RValue::get(CGF.EmitScalarExpr(E)), LV);
1440 llvm_unreachable("bad evaluation kind");
1443 void AggExprEmitter::EmitNullInitializationToLValue(LValue lv) {
1444 QualType type = lv.getType();
1446 // If the destination slot is already zeroed out before the aggregate is
1447 // copied into it, we don't have to emit any zeros here.
1448 if (Dest.isZeroed() && CGF.getTypes().isZeroInitializable(type))
1451 if (CGF.hasScalarEvaluationKind(type)) {
1452 // For non-aggregates, we can store the appropriate null constant.
1453 llvm::Value *null = CGF.CGM.EmitNullConstant(type);
1454 // Note that the following is not equivalent to
1455 // EmitStoreThroughBitfieldLValue for ARC types.
1456 if (lv.isBitField()) {
1457 CGF.EmitStoreThroughBitfieldLValue(RValue::get(null), lv);
1459 assert(lv.isSimple());
1460 CGF.EmitStoreOfScalar(null, lv, /* isInitialization */ true);
1463 // There's a potential optimization opportunity in combining
1464 // memsets; that would be easy for arrays, but relatively
1465 // difficult for structures with the current code.
1466 CGF.EmitNullInitialization(lv.getAddress(CGF), lv.getType());
1470 void AggExprEmitter::VisitInitListExpr(InitListExpr *E) {
1472 // FIXME: Assess perf here? Figure out what cases are worth optimizing here
1473 // (Length of globals? Chunks of zeroed-out space?).
1475 // If we can, prefer a copy from a global; this is a lot less code for long
1476 // globals, and it's easier for the current optimizers to analyze.
1477 if (llvm::Constant* C = CGF.CGM.EmitConstantExpr(E, E->getType(), &CGF)) {
1478 llvm::GlobalVariable* GV =
1479 new llvm::GlobalVariable(CGF.CGM.getModule(), C->getType(), true,
1480 llvm::GlobalValue::InternalLinkage, C, "");
1481 EmitFinalDestCopy(E->getType(), CGF.MakeAddrLValue(GV, E->getType()));
1485 if (E->hadArrayRangeDesignator())
1486 CGF.ErrorUnsupported(E, "GNU array range designator extension");
1488 if (E->isTransparent())
1489 return Visit(E->getInit(0));
1491 AggValueSlot Dest = EnsureSlot(E->getType());
1493 LValue DestLV = CGF.MakeAddrLValue(Dest.getAddress(), E->getType());
1495 // Handle initialization of an array.
1496 if (E->getType()->isArrayType()) {
1497 auto AType = cast<llvm::ArrayType>(Dest.getAddress().getElementType());
1498 EmitArrayInit(Dest.getAddress(), AType, E->getType(), E);
1502 assert(E->getType()->isRecordType() && "Only support structs/unions here!");
1504 // Do struct initialization; this code just sets each individual member
1505 // to the approprate value. This makes bitfield support automatic;
1506 // the disadvantage is that the generated code is more difficult for
1507 // the optimizer, especially with bitfields.
1508 unsigned NumInitElements = E->getNumInits();
1509 RecordDecl *record = E->getType()->castAs<RecordType>()->getDecl();
1511 // We'll need to enter cleanup scopes in case any of the element
1512 // initializers throws an exception.
1513 SmallVector<EHScopeStack::stable_iterator, 16> cleanups;
1514 llvm::Instruction *cleanupDominator = nullptr;
1515 auto addCleanup = [&](const EHScopeStack::stable_iterator &cleanup) {
1516 cleanups.push_back(cleanup);
1517 if (!cleanupDominator) // create placeholder once needed
1518 cleanupDominator = CGF.Builder.CreateAlignedLoad(
1519 CGF.Int8Ty, llvm::Constant::getNullValue(CGF.Int8PtrTy),
1523 unsigned curInitIndex = 0;
1525 // Emit initialization of base classes.
1526 if (auto *CXXRD = dyn_cast<CXXRecordDecl>(record)) {
1527 assert(E->getNumInits() >= CXXRD->getNumBases() &&
1528 "missing initializer for base class");
1529 for (auto &Base : CXXRD->bases()) {
1530 assert(!Base.isVirtual() && "should not see vbases here");
1531 auto *BaseRD = Base.getType()->getAsCXXRecordDecl();
1532 Address V = CGF.GetAddressOfDirectBaseInCompleteClass(
1533 Dest.getAddress(), CXXRD, BaseRD,
1534 /*isBaseVirtual*/ false);
1535 AggValueSlot AggSlot = AggValueSlot::forAddr(
1537 AggValueSlot::IsDestructed,
1538 AggValueSlot::DoesNotNeedGCBarriers,
1539 AggValueSlot::IsNotAliased,
1540 CGF.getOverlapForBaseInit(CXXRD, BaseRD, Base.isVirtual()));
1541 CGF.EmitAggExpr(E->getInit(curInitIndex++), AggSlot);
1543 if (QualType::DestructionKind dtorKind =
1544 Base.getType().isDestructedType()) {
1545 CGF.pushDestroy(dtorKind, V, Base.getType());
1546 addCleanup(CGF.EHStack.stable_begin());
1551 // Prepare a 'this' for CXXDefaultInitExprs.
1552 CodeGenFunction::FieldConstructionScope FCS(CGF, Dest.getAddress());
1554 if (record->isUnion()) {
1555 // Only initialize one field of a union. The field itself is
1556 // specified by the initializer list.
1557 if (!E->getInitializedFieldInUnion()) {
1558 // Empty union; we have nothing to do.
1561 // Make sure that it's really an empty and not a failure of
1562 // semantic analysis.
1563 for (const auto *Field : record->fields())
1564 assert(Field->isUnnamedBitfield() && "Only unnamed bitfields allowed");
1569 // FIXME: volatility
1570 FieldDecl *Field = E->getInitializedFieldInUnion();
1572 LValue FieldLoc = CGF.EmitLValueForFieldInitialization(DestLV, Field);
1573 if (NumInitElements) {
1574 // Store the initializer into the field
1575 EmitInitializationToLValue(E->getInit(0), FieldLoc);
1577 // Default-initialize to null.
1578 EmitNullInitializationToLValue(FieldLoc);
1584 // Here we iterate over the fields; this makes it simpler to both
1585 // default-initialize fields and skip over unnamed fields.
1586 for (const auto *field : record->fields()) {
1587 // We're done once we hit the flexible array member.
1588 if (field->getType()->isIncompleteArrayType())
1591 // Always skip anonymous bitfields.
1592 if (field->isUnnamedBitfield())
1595 // We're done if we reach the end of the explicit initializers, we
1596 // have a zeroed object, and the rest of the fields are
1597 // zero-initializable.
1598 if (curInitIndex == NumInitElements && Dest.isZeroed() &&
1599 CGF.getTypes().isZeroInitializable(E->getType()))
1603 LValue LV = CGF.EmitLValueForFieldInitialization(DestLV, field);
1604 // We never generate write-barries for initialized fields.
1607 if (curInitIndex < NumInitElements) {
1608 // Store the initializer into the field.
1609 EmitInitializationToLValue(E->getInit(curInitIndex++), LV);
1611 // We're out of initializers; default-initialize to null
1612 EmitNullInitializationToLValue(LV);
1615 // Push a destructor if necessary.
1616 // FIXME: if we have an array of structures, all explicitly
1617 // initialized, we can end up pushing a linear number of cleanups.
1618 bool pushedCleanup = false;
1619 if (QualType::DestructionKind dtorKind
1620 = field->getType().isDestructedType()) {
1621 assert(LV.isSimple());
1622 if (CGF.needsEHCleanup(dtorKind)) {
1623 CGF.pushDestroy(EHCleanup, LV.getAddress(CGF), field->getType(),
1624 CGF.getDestroyer(dtorKind), false);
1625 addCleanup(CGF.EHStack.stable_begin());
1626 pushedCleanup = true;
1630 // If the GEP didn't get used because of a dead zero init or something
1631 // else, clean it up for -O0 builds and general tidiness.
1632 if (!pushedCleanup && LV.isSimple())
1633 if (llvm::GetElementPtrInst *GEP =
1634 dyn_cast<llvm::GetElementPtrInst>(LV.getPointer(CGF)))
1635 if (GEP->use_empty())
1636 GEP->eraseFromParent();
1639 // Deactivate all the partial cleanups in reverse order, which
1640 // generally means popping them.
1641 assert((cleanupDominator || cleanups.empty()) &&
1642 "Missing cleanupDominator before deactivating cleanup blocks");
1643 for (unsigned i = cleanups.size(); i != 0; --i)
1644 CGF.DeactivateCleanupBlock(cleanups[i-1], cleanupDominator);
1646 // Destroy the placeholder if we made one.
1647 if (cleanupDominator)
1648 cleanupDominator->eraseFromParent();
1651 void AggExprEmitter::VisitArrayInitLoopExpr(const ArrayInitLoopExpr *E,
1652 llvm::Value *outerBegin) {
1653 // Emit the common subexpression.
1654 CodeGenFunction::OpaqueValueMapping binding(CGF, E->getCommonExpr());
1656 Address destPtr = EnsureSlot(E->getType()).getAddress();
1657 uint64_t numElements = E->getArraySize().getZExtValue();
1662 // destPtr is an array*. Construct an elementType* by drilling down a level.
1663 llvm::Value *zero = llvm::ConstantInt::get(CGF.SizeTy, 0);
1664 llvm::Value *indices[] = {zero, zero};
1665 llvm::Value *begin = Builder.CreateInBoundsGEP(destPtr.getPointer(), indices,
1668 // Prepare to special-case multidimensional array initialization: we avoid
1669 // emitting multiple destructor loops in that case.
1672 ArrayInitLoopExpr *InnerLoop = dyn_cast<ArrayInitLoopExpr>(E->getSubExpr());
1674 QualType elementType =
1675 CGF.getContext().getAsArrayType(E->getType())->getElementType();
1676 CharUnits elementSize = CGF.getContext().getTypeSizeInChars(elementType);
1677 CharUnits elementAlign =
1678 destPtr.getAlignment().alignmentOfArrayElement(elementSize);
1680 llvm::BasicBlock *entryBB = Builder.GetInsertBlock();
1681 llvm::BasicBlock *bodyBB = CGF.createBasicBlock("arrayinit.body");
1683 // Jump into the body.
1684 CGF.EmitBlock(bodyBB);
1685 llvm::PHINode *index =
1686 Builder.CreatePHI(zero->getType(), 2, "arrayinit.index");
1687 index->addIncoming(zero, entryBB);
1688 llvm::Value *element = Builder.CreateInBoundsGEP(begin, index);
1690 // Prepare for a cleanup.
1691 QualType::DestructionKind dtorKind = elementType.isDestructedType();
1692 EHScopeStack::stable_iterator cleanup;
1693 if (CGF.needsEHCleanup(dtorKind) && !InnerLoop) {
1694 if (outerBegin->getType() != element->getType())
1695 outerBegin = Builder.CreateBitCast(outerBegin, element->getType());
1696 CGF.pushRegularPartialArrayCleanup(outerBegin, element, elementType,
1698 CGF.getDestroyer(dtorKind));
1699 cleanup = CGF.EHStack.stable_begin();
1701 dtorKind = QualType::DK_none;
1704 // Emit the actual filler expression.
1706 // Temporaries created in an array initialization loop are destroyed
1707 // at the end of each iteration.
1708 CodeGenFunction::RunCleanupsScope CleanupsScope(CGF);
1709 CodeGenFunction::ArrayInitLoopExprScope Scope(CGF, index);
1711 CGF.MakeAddrLValue(Address(element, elementAlign), elementType);
1714 // If the subexpression is an ArrayInitLoopExpr, share its cleanup.
1715 auto elementSlot = AggValueSlot::forLValue(
1716 elementLV, CGF, AggValueSlot::IsDestructed,
1717 AggValueSlot::DoesNotNeedGCBarriers, AggValueSlot::IsNotAliased,
1718 AggValueSlot::DoesNotOverlap);
1719 AggExprEmitter(CGF, elementSlot, false)
1720 .VisitArrayInitLoopExpr(InnerLoop, outerBegin);
1722 EmitInitializationToLValue(E->getSubExpr(), elementLV);
1725 // Move on to the next element.
1726 llvm::Value *nextIndex = Builder.CreateNUWAdd(
1727 index, llvm::ConstantInt::get(CGF.SizeTy, 1), "arrayinit.next");
1728 index->addIncoming(nextIndex, Builder.GetInsertBlock());
1730 // Leave the loop if we're done.
1731 llvm::Value *done = Builder.CreateICmpEQ(
1732 nextIndex, llvm::ConstantInt::get(CGF.SizeTy, numElements),
1734 llvm::BasicBlock *endBB = CGF.createBasicBlock("arrayinit.end");
1735 Builder.CreateCondBr(done, endBB, bodyBB);
1737 CGF.EmitBlock(endBB);
1739 // Leave the partial-array cleanup if we entered one.
1741 CGF.DeactivateCleanupBlock(cleanup, index);
1744 void AggExprEmitter::VisitDesignatedInitUpdateExpr(DesignatedInitUpdateExpr *E) {
1745 AggValueSlot Dest = EnsureSlot(E->getType());
1747 LValue DestLV = CGF.MakeAddrLValue(Dest.getAddress(), E->getType());
1748 EmitInitializationToLValue(E->getBase(), DestLV);
1749 VisitInitListExpr(E->getUpdater());
1752 //===----------------------------------------------------------------------===//
1753 // Entry Points into this File
1754 //===----------------------------------------------------------------------===//
1756 /// GetNumNonZeroBytesInInit - Get an approximate count of the number of
1757 /// non-zero bytes that will be stored when outputting the initializer for the
1758 /// specified initializer expression.
1759 static CharUnits GetNumNonZeroBytesInInit(const Expr *E, CodeGenFunction &CGF) {
1760 E = E->IgnoreParens();
1762 // 0 and 0.0 won't require any non-zero stores!
1763 if (isSimpleZero(E, CGF)) return CharUnits::Zero();
1765 // If this is an initlist expr, sum up the size of sizes of the (present)
1766 // elements. If this is something weird, assume the whole thing is non-zero.
1767 const InitListExpr *ILE = dyn_cast<InitListExpr>(E);
1768 while (ILE && ILE->isTransparent())
1769 ILE = dyn_cast<InitListExpr>(ILE->getInit(0));
1770 if (!ILE || !CGF.getTypes().isZeroInitializable(ILE->getType()))
1771 return CGF.getContext().getTypeSizeInChars(E->getType());
1773 // InitListExprs for structs have to be handled carefully. If there are
1774 // reference members, we need to consider the size of the reference, not the
1775 // referencee. InitListExprs for unions and arrays can't have references.
1776 if (const RecordType *RT = E->getType()->getAs<RecordType>()) {
1777 if (!RT->isUnionType()) {
1778 RecordDecl *SD = RT->getDecl();
1779 CharUnits NumNonZeroBytes = CharUnits::Zero();
1781 unsigned ILEElement = 0;
1782 if (auto *CXXRD = dyn_cast<CXXRecordDecl>(SD))
1783 while (ILEElement != CXXRD->getNumBases())
1785 GetNumNonZeroBytesInInit(ILE->getInit(ILEElement++), CGF);
1786 for (const auto *Field : SD->fields()) {
1787 // We're done once we hit the flexible array member or run out of
1788 // InitListExpr elements.
1789 if (Field->getType()->isIncompleteArrayType() ||
1790 ILEElement == ILE->getNumInits())
1792 if (Field->isUnnamedBitfield())
1795 const Expr *E = ILE->getInit(ILEElement++);
1797 // Reference values are always non-null and have the width of a pointer.
1798 if (Field->getType()->isReferenceType())
1799 NumNonZeroBytes += CGF.getContext().toCharUnitsFromBits(
1800 CGF.getTarget().getPointerWidth(0));
1802 NumNonZeroBytes += GetNumNonZeroBytesInInit(E, CGF);
1805 return NumNonZeroBytes;
1810 CharUnits NumNonZeroBytes = CharUnits::Zero();
1811 for (unsigned i = 0, e = ILE->getNumInits(); i != e; ++i)
1812 NumNonZeroBytes += GetNumNonZeroBytesInInit(ILE->getInit(i), CGF);
1813 return NumNonZeroBytes;
1816 /// CheckAggExprForMemSetUse - If the initializer is large and has a lot of
1817 /// zeros in it, emit a memset and avoid storing the individual zeros.
1819 static void CheckAggExprForMemSetUse(AggValueSlot &Slot, const Expr *E,
1820 CodeGenFunction &CGF) {
1821 // If the slot is already known to be zeroed, nothing to do. Don't mess with
1823 if (Slot.isZeroed() || Slot.isVolatile() || !Slot.getAddress().isValid())
1826 // C++ objects with a user-declared constructor don't need zero'ing.
1827 if (CGF.getLangOpts().CPlusPlus)
1828 if (const RecordType *RT = CGF.getContext()
1829 .getBaseElementType(E->getType())->getAs<RecordType>()) {
1830 const CXXRecordDecl *RD = cast<CXXRecordDecl>(RT->getDecl());
1831 if (RD->hasUserDeclaredConstructor())
1835 // If the type is 16-bytes or smaller, prefer individual stores over memset.
1836 CharUnits Size = Slot.getPreferredSize(CGF.getContext(), E->getType());
1837 if (Size <= CharUnits::fromQuantity(16))
1840 // Check to see if over 3/4 of the initializer are known to be zero. If so,
1841 // we prefer to emit memset + individual stores for the rest.
1842 CharUnits NumNonZeroBytes = GetNumNonZeroBytesInInit(E, CGF);
1843 if (NumNonZeroBytes*4 > Size)
1846 // Okay, it seems like a good idea to use an initial memset, emit the call.
1847 llvm::Constant *SizeVal = CGF.Builder.getInt64(Size.getQuantity());
1849 Address Loc = Slot.getAddress();
1850 Loc = CGF.Builder.CreateElementBitCast(Loc, CGF.Int8Ty);
1851 CGF.Builder.CreateMemSet(Loc, CGF.Builder.getInt8(0), SizeVal, false);
1853 // Tell the AggExprEmitter that the slot is known zero.
1860 /// EmitAggExpr - Emit the computation of the specified expression of aggregate
1861 /// type. The result is computed into DestPtr. Note that if DestPtr is null,
1862 /// the value of the aggregate expression is not needed. If VolatileDest is
1863 /// true, DestPtr cannot be 0.
1864 void CodeGenFunction::EmitAggExpr(const Expr *E, AggValueSlot Slot) {
1865 assert(E && hasAggregateEvaluationKind(E->getType()) &&
1866 "Invalid aggregate expression to emit");
1867 assert((Slot.getAddress().isValid() || Slot.isIgnored()) &&
1868 "slot has bits but no address");
1870 // Optimize the slot if possible.
1871 CheckAggExprForMemSetUse(Slot, E, *this);
1873 AggExprEmitter(*this, Slot, Slot.isIgnored()).Visit(const_cast<Expr*>(E));
1876 LValue CodeGenFunction::EmitAggExprToLValue(const Expr *E) {
1877 assert(hasAggregateEvaluationKind(E->getType()) && "Invalid argument!");
1878 Address Temp = CreateMemTemp(E->getType());
1879 LValue LV = MakeAddrLValue(Temp, E->getType());
1880 EmitAggExpr(E, AggValueSlot::forLValue(
1881 LV, *this, AggValueSlot::IsNotDestructed,
1882 AggValueSlot::DoesNotNeedGCBarriers,
1883 AggValueSlot::IsNotAliased, AggValueSlot::DoesNotOverlap));
1887 AggValueSlot::Overlap_t
1888 CodeGenFunction::getOverlapForFieldInit(const FieldDecl *FD) {
1889 if (!FD->hasAttr<NoUniqueAddressAttr>() || !FD->getType()->isRecordType())
1890 return AggValueSlot::DoesNotOverlap;
1892 // If the field lies entirely within the enclosing class's nvsize, its tail
1893 // padding cannot overlap any already-initialized object. (The only subobjects
1894 // with greater addresses that might already be initialized are vbases.)
1895 const RecordDecl *ClassRD = FD->getParent();
1896 const ASTRecordLayout &Layout = getContext().getASTRecordLayout(ClassRD);
1897 if (Layout.getFieldOffset(FD->getFieldIndex()) +
1898 getContext().getTypeSize(FD->getType()) <=
1899 (uint64_t)getContext().toBits(Layout.getNonVirtualSize()))
1900 return AggValueSlot::DoesNotOverlap;
1902 // The tail padding may contain values we need to preserve.
1903 return AggValueSlot::MayOverlap;
1906 AggValueSlot::Overlap_t CodeGenFunction::getOverlapForBaseInit(
1907 const CXXRecordDecl *RD, const CXXRecordDecl *BaseRD, bool IsVirtual) {
1908 // If the most-derived object is a field declared with [[no_unique_address]],
1909 // the tail padding of any virtual base could be reused for other subobjects
1910 // of that field's class.
1912 return AggValueSlot::MayOverlap;
1914 // If the base class is laid out entirely within the nvsize of the derived
1915 // class, its tail padding cannot yet be initialized, so we can issue
1916 // stores at the full width of the base class.
1917 const ASTRecordLayout &Layout = getContext().getASTRecordLayout(RD);
1918 if (Layout.getBaseClassOffset(BaseRD) +
1919 getContext().getASTRecordLayout(BaseRD).getSize() <=
1920 Layout.getNonVirtualSize())
1921 return AggValueSlot::DoesNotOverlap;
1923 // The tail padding may contain values we need to preserve.
1924 return AggValueSlot::MayOverlap;
1927 void CodeGenFunction::EmitAggregateCopy(LValue Dest, LValue Src, QualType Ty,
1928 AggValueSlot::Overlap_t MayOverlap,
1930 assert(!Ty->isAnyComplexType() && "Shouldn't happen for complex");
1932 Address DestPtr = Dest.getAddress(*this);
1933 Address SrcPtr = Src.getAddress(*this);
1935 if (getLangOpts().CPlusPlus) {
1936 if (const RecordType *RT = Ty->getAs<RecordType>()) {
1937 CXXRecordDecl *Record = cast<CXXRecordDecl>(RT->getDecl());
1938 assert((Record->hasTrivialCopyConstructor() ||
1939 Record->hasTrivialCopyAssignment() ||
1940 Record->hasTrivialMoveConstructor() ||
1941 Record->hasTrivialMoveAssignment() ||
1942 Record->isUnion()) &&
1943 "Trying to aggregate-copy a type without a trivial copy/move "
1944 "constructor or assignment operator");
1945 // Ignore empty classes in C++.
1946 if (Record->isEmpty())
1951 if (getLangOpts().CUDAIsDevice) {
1952 if (Ty->isCUDADeviceBuiltinSurfaceType()) {
1953 if (getTargetHooks().emitCUDADeviceBuiltinSurfaceDeviceCopy(*this, Dest,
1956 } else if (Ty->isCUDADeviceBuiltinTextureType()) {
1957 if (getTargetHooks().emitCUDADeviceBuiltinTextureDeviceCopy(*this, Dest,
1963 // Aggregate assignment turns into llvm.memcpy. This is almost valid per
1964 // C99 6.5.16.1p3, which states "If the value being stored in an object is
1965 // read from another object that overlaps in anyway the storage of the first
1966 // object, then the overlap shall be exact and the two objects shall have
1967 // qualified or unqualified versions of a compatible type."
1969 // memcpy is not defined if the source and destination pointers are exactly
1970 // equal, but other compilers do this optimization, and almost every memcpy
1971 // implementation handles this case safely. If there is a libc that does not
1972 // safely handle this, we can add a target hook.
1974 // Get data size info for this aggregate. Don't copy the tail padding if this
1975 // might be a potentially-overlapping subobject, since the tail padding might
1976 // be occupied by a different object. Otherwise, copying it is fine.
1977 std::pair<CharUnits, CharUnits> TypeInfo;
1979 TypeInfo = getContext().getTypeInfoDataSizeInChars(Ty);
1981 TypeInfo = getContext().getTypeInfoInChars(Ty);
1983 llvm::Value *SizeVal = nullptr;
1984 if (TypeInfo.first.isZero()) {
1985 // But note that getTypeInfo returns 0 for a VLA.
1986 if (auto *VAT = dyn_cast_or_null<VariableArrayType>(
1987 getContext().getAsArrayType(Ty))) {
1989 SizeVal = emitArrayLength(VAT, BaseEltTy, DestPtr);
1990 TypeInfo = getContext().getTypeInfoInChars(BaseEltTy);
1991 assert(!TypeInfo.first.isZero());
1992 SizeVal = Builder.CreateNUWMul(
1994 llvm::ConstantInt::get(SizeTy, TypeInfo.first.getQuantity()));
1998 SizeVal = llvm::ConstantInt::get(SizeTy, TypeInfo.first.getQuantity());
2001 // FIXME: If we have a volatile struct, the optimizer can remove what might
2002 // appear to be `extra' memory ops:
2004 // volatile struct { int i; } a, b;
2011 // we need to use a different call here. We use isVolatile to indicate when
2012 // either the source or the destination is volatile.
2014 DestPtr = Builder.CreateElementBitCast(DestPtr, Int8Ty);
2015 SrcPtr = Builder.CreateElementBitCast(SrcPtr, Int8Ty);
2017 // Don't do any of the memmove_collectable tests if GC isn't set.
2018 if (CGM.getLangOpts().getGC() == LangOptions::NonGC) {
2020 } else if (const RecordType *RecordTy = Ty->getAs<RecordType>()) {
2021 RecordDecl *Record = RecordTy->getDecl();
2022 if (Record->hasObjectMember()) {
2023 CGM.getObjCRuntime().EmitGCMemmoveCollectable(*this, DestPtr, SrcPtr,
2027 } else if (Ty->isArrayType()) {
2028 QualType BaseType = getContext().getBaseElementType(Ty);
2029 if (const RecordType *RecordTy = BaseType->getAs<RecordType>()) {
2030 if (RecordTy->getDecl()->hasObjectMember()) {
2031 CGM.getObjCRuntime().EmitGCMemmoveCollectable(*this, DestPtr, SrcPtr,
2038 auto Inst = Builder.CreateMemCpy(DestPtr, SrcPtr, SizeVal, isVolatile);
2040 // Determine the metadata to describe the position of any padding in this
2041 // memcpy, as well as the TBAA tags for the members of the struct, in case
2042 // the optimizer wishes to expand it in to scalar memory operations.
2043 if (llvm::MDNode *TBAAStructTag = CGM.getTBAAStructInfo(Ty))
2044 Inst->setMetadata(llvm::LLVMContext::MD_tbaa_struct, TBAAStructTag);
2046 if (CGM.getCodeGenOpts().NewStructPathTBAA) {
2047 TBAAAccessInfo TBAAInfo = CGM.mergeTBAAInfoForMemoryTransfer(
2048 Dest.getTBAAInfo(), Src.getTBAAInfo());
2049 CGM.DecorateInstructionWithTBAA(Inst, TBAAInfo);