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 "clang/AST/ASTContext.h"
19 #include "clang/AST/Attr.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/IntrinsicInst.h"
27 #include "llvm/IR/Intrinsics.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());
128 void VisitConstantExpr(ConstantExpr *E) {
129 return Visit(E->getSubExpr());
133 void VisitDeclRefExpr(DeclRefExpr *E) { EmitAggLoadOfLValue(E); }
134 void VisitMemberExpr(MemberExpr *ME) { EmitAggLoadOfLValue(ME); }
135 void VisitUnaryDeref(UnaryOperator *E) { EmitAggLoadOfLValue(E); }
136 void VisitStringLiteral(StringLiteral *E) { EmitAggLoadOfLValue(E); }
137 void VisitCompoundLiteralExpr(CompoundLiteralExpr *E);
138 void VisitArraySubscriptExpr(ArraySubscriptExpr *E) {
139 EmitAggLoadOfLValue(E);
141 void VisitPredefinedExpr(const PredefinedExpr *E) {
142 EmitAggLoadOfLValue(E);
146 void VisitCastExpr(CastExpr *E);
147 void VisitCallExpr(const CallExpr *E);
148 void VisitStmtExpr(const StmtExpr *E);
149 void VisitBinaryOperator(const BinaryOperator *BO);
150 void VisitPointerToDataMemberBinaryOperator(const BinaryOperator *BO);
151 void VisitBinAssign(const BinaryOperator *E);
152 void VisitBinComma(const BinaryOperator *E);
153 void VisitBinCmp(const BinaryOperator *E);
154 void VisitCXXRewrittenBinaryOperator(CXXRewrittenBinaryOperator *E) {
155 Visit(E->getSemanticForm());
158 void VisitObjCMessageExpr(ObjCMessageExpr *E);
159 void VisitObjCIvarRefExpr(ObjCIvarRefExpr *E) {
160 EmitAggLoadOfLValue(E);
163 void VisitDesignatedInitUpdateExpr(DesignatedInitUpdateExpr *E);
164 void VisitAbstractConditionalOperator(const AbstractConditionalOperator *CO);
165 void VisitChooseExpr(const ChooseExpr *CE);
166 void VisitInitListExpr(InitListExpr *E);
167 void VisitArrayInitLoopExpr(const ArrayInitLoopExpr *E,
168 llvm::Value *outerBegin = nullptr);
169 void VisitImplicitValueInitExpr(ImplicitValueInitExpr *E);
170 void VisitNoInitExpr(NoInitExpr *E) { } // Do nothing.
171 void VisitCXXDefaultArgExpr(CXXDefaultArgExpr *DAE) {
172 CodeGenFunction::CXXDefaultArgExprScope Scope(CGF, DAE);
173 Visit(DAE->getExpr());
175 void VisitCXXDefaultInitExpr(CXXDefaultInitExpr *DIE) {
176 CodeGenFunction::CXXDefaultInitExprScope Scope(CGF, DIE);
177 Visit(DIE->getExpr());
179 void VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E);
180 void VisitCXXConstructExpr(const CXXConstructExpr *E);
181 void VisitCXXInheritedCtorInitExpr(const CXXInheritedCtorInitExpr *E);
182 void VisitLambdaExpr(LambdaExpr *E);
183 void VisitCXXStdInitializerListExpr(CXXStdInitializerListExpr *E);
184 void VisitExprWithCleanups(ExprWithCleanups *E);
185 void VisitCXXScalarValueInitExpr(CXXScalarValueInitExpr *E);
186 void VisitCXXTypeidExpr(CXXTypeidExpr *E) { EmitAggLoadOfLValue(E); }
187 void VisitMaterializeTemporaryExpr(MaterializeTemporaryExpr *E);
188 void VisitOpaqueValueExpr(OpaqueValueExpr *E);
190 void VisitPseudoObjectExpr(PseudoObjectExpr *E) {
191 if (E->isGLValue()) {
192 LValue LV = CGF.EmitPseudoObjectLValue(E);
193 return EmitFinalDestCopy(E->getType(), LV);
196 CGF.EmitPseudoObjectRValue(E, EnsureSlot(E->getType()));
199 void VisitVAArgExpr(VAArgExpr *E);
201 void EmitInitializationToLValue(Expr *E, LValue Address);
202 void EmitNullInitializationToLValue(LValue Address);
203 // case Expr::ChooseExprClass:
204 void VisitCXXThrowExpr(const CXXThrowExpr *E) { CGF.EmitCXXThrowExpr(E); }
205 void VisitAtomicExpr(AtomicExpr *E) {
206 RValue Res = CGF.EmitAtomicExpr(E);
207 EmitFinalDestCopy(E->getType(), Res);
210 } // end anonymous namespace.
212 //===----------------------------------------------------------------------===//
214 //===----------------------------------------------------------------------===//
216 /// EmitAggLoadOfLValue - Given an expression with aggregate type that
217 /// represents a value lvalue, this method emits the address of the lvalue,
218 /// then loads the result into DestPtr.
219 void AggExprEmitter::EmitAggLoadOfLValue(const Expr *E) {
220 LValue LV = CGF.EmitLValue(E);
222 // If the type of the l-value is atomic, then do an atomic load.
223 if (LV.getType()->isAtomicType() || CGF.LValueIsSuitableForInlineAtomic(LV)) {
224 CGF.EmitAtomicLoad(LV, E->getExprLoc(), Dest);
228 EmitFinalDestCopy(E->getType(), LV);
231 /// True if the given aggregate type requires special GC API calls.
232 bool AggExprEmitter::TypeRequiresGCollection(QualType T) {
233 // Only record types have members that might require garbage collection.
234 const RecordType *RecordTy = T->getAs<RecordType>();
235 if (!RecordTy) return false;
237 // Don't mess with non-trivial C++ types.
238 RecordDecl *Record = RecordTy->getDecl();
239 if (isa<CXXRecordDecl>(Record) &&
240 (cast<CXXRecordDecl>(Record)->hasNonTrivialCopyConstructor() ||
241 !cast<CXXRecordDecl>(Record)->hasTrivialDestructor()))
244 // Check whether the type has an object member.
245 return Record->hasObjectMember();
248 void AggExprEmitter::withReturnValueSlot(
249 const Expr *E, llvm::function_ref<RValue(ReturnValueSlot)> EmitCall) {
250 QualType RetTy = E->getType();
251 bool RequiresDestruction =
253 RetTy.isDestructedType() == QualType::DK_nontrivial_c_struct;
255 // If it makes no observable difference, save a memcpy + temporary.
257 // We need to always provide our own temporary if destruction is required.
258 // Otherwise, EmitCall will emit its own, notice that it's "unused", and end
259 // its lifetime before we have the chance to emit a proper destructor call.
260 bool UseTemp = Dest.isPotentiallyAliased() || Dest.requiresGCollection() ||
261 (RequiresDestruction && !Dest.getAddress().isValid());
263 Address RetAddr = Address::invalid();
264 Address RetAllocaAddr = Address::invalid();
266 EHScopeStack::stable_iterator LifetimeEndBlock;
267 llvm::Value *LifetimeSizePtr = nullptr;
268 llvm::IntrinsicInst *LifetimeStartInst = nullptr;
270 RetAddr = Dest.getAddress();
272 RetAddr = CGF.CreateMemTemp(RetTy, "tmp", &RetAllocaAddr);
274 CGF.CGM.getDataLayout().getTypeAllocSize(CGF.ConvertTypeForMem(RetTy));
275 LifetimeSizePtr = CGF.EmitLifetimeStart(Size, RetAllocaAddr.getPointer());
276 if (LifetimeSizePtr) {
278 cast<llvm::IntrinsicInst>(std::prev(Builder.GetInsertPoint()));
279 assert(LifetimeStartInst->getIntrinsicID() ==
280 llvm::Intrinsic::lifetime_start &&
281 "Last insertion wasn't a lifetime.start?");
283 CGF.pushFullExprCleanup<CodeGenFunction::CallLifetimeEnd>(
284 NormalEHLifetimeMarker, RetAllocaAddr, LifetimeSizePtr);
285 LifetimeEndBlock = CGF.EHStack.stable_begin();
290 EmitCall(ReturnValueSlot(RetAddr, Dest.isVolatile(), IsResultUnused));
292 if (RequiresDestruction)
293 CGF.pushDestroy(RetTy.isDestructedType(), Src.getAggregateAddress(), RetTy);
298 assert(Dest.getPointer() != Src.getAggregatePointer());
299 EmitFinalDestCopy(E->getType(), Src);
301 if (!RequiresDestruction && LifetimeStartInst) {
302 // If there's no dtor to run, the copy was the last use of our temporary.
303 // Since we're not guaranteed to be in an ExprWithCleanups, clean up
305 CGF.DeactivateCleanupBlock(LifetimeEndBlock, LifetimeStartInst);
306 CGF.EmitLifetimeEnd(LifetimeSizePtr, RetAllocaAddr.getPointer());
310 /// EmitFinalDestCopy - Perform the final copy to DestPtr, if desired.
311 void AggExprEmitter::EmitFinalDestCopy(QualType type, RValue src) {
312 assert(src.isAggregate() && "value must be aggregate value!");
313 LValue srcLV = CGF.MakeAddrLValue(src.getAggregateAddress(), type);
314 EmitFinalDestCopy(type, srcLV, EVK_RValue);
317 /// EmitFinalDestCopy - Perform the final copy to DestPtr, if desired.
318 void AggExprEmitter::EmitFinalDestCopy(QualType type, const LValue &src,
319 ExprValueKind SrcValueKind) {
320 // If Dest is ignored, then we're evaluating an aggregate expression
321 // in a context that doesn't care about the result. Note that loads
322 // from volatile l-values force the existence of a non-ignored
324 if (Dest.isIgnored())
327 // Copy non-trivial C structs here.
328 LValue DstLV = CGF.MakeAddrLValue(
329 Dest.getAddress(), Dest.isVolatile() ? type.withVolatile() : type);
331 if (SrcValueKind == EVK_RValue) {
332 if (type.isNonTrivialToPrimitiveDestructiveMove() == QualType::PCK_Struct) {
333 if (Dest.isPotentiallyAliased())
334 CGF.callCStructMoveAssignmentOperator(DstLV, src);
336 CGF.callCStructMoveConstructor(DstLV, src);
340 if (type.isNonTrivialToPrimitiveCopy() == QualType::PCK_Struct) {
341 if (Dest.isPotentiallyAliased())
342 CGF.callCStructCopyAssignmentOperator(DstLV, src);
344 CGF.callCStructCopyConstructor(DstLV, src);
349 AggValueSlot srcAgg = AggValueSlot::forLValue(
350 src, CGF, AggValueSlot::IsDestructed, needsGC(type),
351 AggValueSlot::IsAliased, AggValueSlot::MayOverlap);
352 EmitCopy(type, Dest, srcAgg);
355 /// Perform a copy from the source into the destination.
357 /// \param type - the type of the aggregate being copied; qualifiers are
359 void AggExprEmitter::EmitCopy(QualType type, const AggValueSlot &dest,
360 const AggValueSlot &src) {
361 if (dest.requiresGCollection()) {
362 CharUnits sz = dest.getPreferredSize(CGF.getContext(), type);
363 llvm::Value *size = llvm::ConstantInt::get(CGF.SizeTy, sz.getQuantity());
364 CGF.CGM.getObjCRuntime().EmitGCMemmoveCollectable(CGF,
371 // If the result of the assignment is used, copy the LHS there also.
372 // It's volatile if either side is. Use the minimum alignment of
374 LValue DestLV = CGF.MakeAddrLValue(dest.getAddress(), type);
375 LValue SrcLV = CGF.MakeAddrLValue(src.getAddress(), type);
376 CGF.EmitAggregateCopy(DestLV, SrcLV, type, dest.mayOverlap(),
377 dest.isVolatile() || src.isVolatile());
380 /// Emit the initializer for a std::initializer_list initialized with a
381 /// real initializer list.
383 AggExprEmitter::VisitCXXStdInitializerListExpr(CXXStdInitializerListExpr *E) {
384 // Emit an array containing the elements. The array is externally destructed
385 // if the std::initializer_list object is.
386 ASTContext &Ctx = CGF.getContext();
387 LValue Array = CGF.EmitLValue(E->getSubExpr());
388 assert(Array.isSimple() && "initializer_list array not a simple lvalue");
389 Address ArrayPtr = Array.getAddress(CGF);
391 const ConstantArrayType *ArrayType =
392 Ctx.getAsConstantArrayType(E->getSubExpr()->getType());
393 assert(ArrayType && "std::initializer_list constructed from non-array");
395 // FIXME: Perform the checks on the field types in SemaInit.
396 RecordDecl *Record = E->getType()->castAs<RecordType>()->getDecl();
397 RecordDecl::field_iterator Field = Record->field_begin();
398 if (Field == Record->field_end()) {
399 CGF.ErrorUnsupported(E, "weird std::initializer_list");
404 if (!Field->getType()->isPointerType() ||
405 !Ctx.hasSameType(Field->getType()->getPointeeType(),
406 ArrayType->getElementType())) {
407 CGF.ErrorUnsupported(E, "weird std::initializer_list");
411 AggValueSlot Dest = EnsureSlot(E->getType());
412 LValue DestLV = CGF.MakeAddrLValue(Dest.getAddress(), E->getType());
413 LValue Start = CGF.EmitLValueForFieldInitialization(DestLV, *Field);
414 llvm::Value *Zero = llvm::ConstantInt::get(CGF.PtrDiffTy, 0);
415 llvm::Value *IdxStart[] = { Zero, Zero };
416 llvm::Value *ArrayStart =
417 Builder.CreateInBoundsGEP(ArrayPtr.getPointer(), IdxStart, "arraystart");
418 CGF.EmitStoreThroughLValue(RValue::get(ArrayStart), Start);
421 if (Field == Record->field_end()) {
422 CGF.ErrorUnsupported(E, "weird std::initializer_list");
426 llvm::Value *Size = Builder.getInt(ArrayType->getSize());
427 LValue EndOrLength = CGF.EmitLValueForFieldInitialization(DestLV, *Field);
428 if (Field->getType()->isPointerType() &&
429 Ctx.hasSameType(Field->getType()->getPointeeType(),
430 ArrayType->getElementType())) {
432 llvm::Value *IdxEnd[] = { Zero, Size };
433 llvm::Value *ArrayEnd =
434 Builder.CreateInBoundsGEP(ArrayPtr.getPointer(), IdxEnd, "arrayend");
435 CGF.EmitStoreThroughLValue(RValue::get(ArrayEnd), EndOrLength);
436 } else if (Ctx.hasSameType(Field->getType(), Ctx.getSizeType())) {
438 CGF.EmitStoreThroughLValue(RValue::get(Size), EndOrLength);
440 CGF.ErrorUnsupported(E, "weird std::initializer_list");
445 /// Determine if E is a trivial array filler, that is, one that is
446 /// equivalent to zero-initialization.
447 static bool isTrivialFiller(Expr *E) {
451 if (isa<ImplicitValueInitExpr>(E))
454 if (auto *ILE = dyn_cast<InitListExpr>(E)) {
455 if (ILE->getNumInits())
457 return isTrivialFiller(ILE->getArrayFiller());
460 if (auto *Cons = dyn_cast_or_null<CXXConstructExpr>(E))
461 return Cons->getConstructor()->isDefaultConstructor() &&
462 Cons->getConstructor()->isTrivial();
464 // FIXME: Are there other cases where we can avoid emitting an initializer?
468 /// Emit initialization of an array from an initializer list.
469 void AggExprEmitter::EmitArrayInit(Address DestPtr, llvm::ArrayType *AType,
470 QualType ArrayQTy, InitListExpr *E) {
471 uint64_t NumInitElements = E->getNumInits();
473 uint64_t NumArrayElements = AType->getNumElements();
474 assert(NumInitElements <= NumArrayElements);
476 QualType elementType =
477 CGF.getContext().getAsArrayType(ArrayQTy)->getElementType();
479 // DestPtr is an array*. Construct an elementType* by drilling
481 llvm::Value *zero = llvm::ConstantInt::get(CGF.SizeTy, 0);
482 llvm::Value *indices[] = { zero, zero };
484 Builder.CreateInBoundsGEP(DestPtr.getPointer(), indices, "arrayinit.begin");
486 CharUnits elementSize = CGF.getContext().getTypeSizeInChars(elementType);
487 CharUnits elementAlign =
488 DestPtr.getAlignment().alignmentOfArrayElement(elementSize);
490 // Consider initializing the array by copying from a global. For this to be
491 // more efficient than per-element initialization, the size of the elements
492 // with explicit initializers should be large enough.
493 if (NumInitElements * elementSize.getQuantity() > 16 &&
494 elementType.isTriviallyCopyableType(CGF.getContext())) {
495 CodeGen::CodeGenModule &CGM = CGF.CGM;
496 ConstantEmitter Emitter(CGF);
497 LangAS AS = ArrayQTy.getAddressSpace();
498 if (llvm::Constant *C = Emitter.tryEmitForInitializer(E, AS, ArrayQTy)) {
499 auto GV = new llvm::GlobalVariable(
500 CGM.getModule(), C->getType(),
501 CGM.isTypeConstant(ArrayQTy, /* ExcludeCtorDtor= */ true),
502 llvm::GlobalValue::PrivateLinkage, C, "constinit",
503 /* InsertBefore= */ nullptr, llvm::GlobalVariable::NotThreadLocal,
504 CGM.getContext().getTargetAddressSpace(AS));
505 Emitter.finalize(GV);
506 CharUnits Align = CGM.getContext().getTypeAlignInChars(ArrayQTy);
507 GV->setAlignment(Align.getAsAlign());
508 EmitFinalDestCopy(ArrayQTy, CGF.MakeAddrLValue(GV, ArrayQTy, Align));
513 // Exception safety requires us to destroy all the
514 // already-constructed members if an initializer throws.
515 // For that, we'll need an EH cleanup.
516 QualType::DestructionKind dtorKind = elementType.isDestructedType();
517 Address endOfInit = Address::invalid();
518 EHScopeStack::stable_iterator cleanup;
519 llvm::Instruction *cleanupDominator = nullptr;
520 if (CGF.needsEHCleanup(dtorKind)) {
521 // In principle we could tell the cleanup where we are more
522 // directly, but the control flow can get so varied here that it
523 // would actually be quite complex. Therefore we go through an
525 endOfInit = CGF.CreateTempAlloca(begin->getType(), CGF.getPointerAlign(),
526 "arrayinit.endOfInit");
527 cleanupDominator = Builder.CreateStore(begin, endOfInit);
528 CGF.pushIrregularPartialArrayCleanup(begin, endOfInit, elementType,
530 CGF.getDestroyer(dtorKind));
531 cleanup = CGF.EHStack.stable_begin();
533 // Otherwise, remember that we didn't need a cleanup.
535 dtorKind = QualType::DK_none;
538 llvm::Value *one = llvm::ConstantInt::get(CGF.SizeTy, 1);
540 // The 'current element to initialize'. The invariants on this
541 // variable are complicated. Essentially, after each iteration of
542 // the loop, it points to the last initialized element, except
543 // that it points to the beginning of the array before any
544 // elements have been initialized.
545 llvm::Value *element = begin;
547 // Emit the explicit initializers.
548 for (uint64_t i = 0; i != NumInitElements; ++i) {
549 // Advance to the next element.
551 element = Builder.CreateInBoundsGEP(element, one, "arrayinit.element");
553 // Tell the cleanup that it needs to destroy up to this
554 // element. TODO: some of these stores can be trivially
555 // observed to be unnecessary.
556 if (endOfInit.isValid()) Builder.CreateStore(element, endOfInit);
560 CGF.MakeAddrLValue(Address(element, elementAlign), elementType);
561 EmitInitializationToLValue(E->getInit(i), elementLV);
564 // Check whether there's a non-trivial array-fill expression.
565 Expr *filler = E->getArrayFiller();
566 bool hasTrivialFiller = isTrivialFiller(filler);
568 // Any remaining elements need to be zero-initialized, possibly
569 // using the filler expression. We can skip this if the we're
570 // emitting to zeroed memory.
571 if (NumInitElements != NumArrayElements &&
572 !(Dest.isZeroed() && hasTrivialFiller &&
573 CGF.getTypes().isZeroInitializable(elementType))) {
575 // Use an actual loop. This is basically
576 // do { *array++ = filler; } while (array != end);
578 // Advance to the start of the rest of the array.
579 if (NumInitElements) {
580 element = Builder.CreateInBoundsGEP(element, one, "arrayinit.start");
581 if (endOfInit.isValid()) Builder.CreateStore(element, endOfInit);
584 // Compute the end of the array.
585 llvm::Value *end = Builder.CreateInBoundsGEP(begin,
586 llvm::ConstantInt::get(CGF.SizeTy, NumArrayElements),
589 llvm::BasicBlock *entryBB = Builder.GetInsertBlock();
590 llvm::BasicBlock *bodyBB = CGF.createBasicBlock("arrayinit.body");
592 // Jump into the body.
593 CGF.EmitBlock(bodyBB);
594 llvm::PHINode *currentElement =
595 Builder.CreatePHI(element->getType(), 2, "arrayinit.cur");
596 currentElement->addIncoming(element, entryBB);
598 // Emit the actual filler expression.
600 // C++1z [class.temporary]p5:
601 // when a default constructor is called to initialize an element of
602 // an array with no corresponding initializer [...] the destruction of
603 // every temporary created in a default argument is sequenced before
604 // the construction of the next array element, if any
605 CodeGenFunction::RunCleanupsScope CleanupsScope(CGF);
607 CGF.MakeAddrLValue(Address(currentElement, elementAlign), elementType);
609 EmitInitializationToLValue(filler, elementLV);
611 EmitNullInitializationToLValue(elementLV);
614 // Move on to the next element.
615 llvm::Value *nextElement =
616 Builder.CreateInBoundsGEP(currentElement, one, "arrayinit.next");
618 // Tell the EH cleanup that we finished with the last element.
619 if (endOfInit.isValid()) Builder.CreateStore(nextElement, endOfInit);
621 // Leave the loop if we're done.
622 llvm::Value *done = Builder.CreateICmpEQ(nextElement, end,
624 llvm::BasicBlock *endBB = CGF.createBasicBlock("arrayinit.end");
625 Builder.CreateCondBr(done, endBB, bodyBB);
626 currentElement->addIncoming(nextElement, Builder.GetInsertBlock());
628 CGF.EmitBlock(endBB);
631 // Leave the partial-array cleanup if we entered one.
632 if (dtorKind) CGF.DeactivateCleanupBlock(cleanup, cleanupDominator);
635 //===----------------------------------------------------------------------===//
637 //===----------------------------------------------------------------------===//
639 void AggExprEmitter::VisitMaterializeTemporaryExpr(MaterializeTemporaryExpr *E){
640 Visit(E->getSubExpr());
643 void AggExprEmitter::VisitOpaqueValueExpr(OpaqueValueExpr *e) {
644 // If this is a unique OVE, just visit its source expression.
646 Visit(e->getSourceExpr());
648 EmitFinalDestCopy(e->getType(), CGF.getOrCreateOpaqueLValueMapping(e));
652 AggExprEmitter::VisitCompoundLiteralExpr(CompoundLiteralExpr *E) {
653 if (Dest.isPotentiallyAliased() &&
654 E->getType().isPODType(CGF.getContext())) {
655 // For a POD type, just emit a load of the lvalue + a copy, because our
656 // compound literal might alias the destination.
657 EmitAggLoadOfLValue(E);
661 AggValueSlot Slot = EnsureSlot(E->getType());
662 CGF.EmitAggExpr(E->getInitializer(), Slot);
665 /// Attempt to look through various unimportant expressions to find a
666 /// cast of the given kind.
667 static Expr *findPeephole(Expr *op, CastKind kind) {
669 op = op->IgnoreParens();
670 if (CastExpr *castE = dyn_cast<CastExpr>(op)) {
671 if (castE->getCastKind() == kind)
672 return castE->getSubExpr();
673 if (castE->getCastKind() == CK_NoOp)
680 void AggExprEmitter::VisitCastExpr(CastExpr *E) {
681 if (const auto *ECE = dyn_cast<ExplicitCastExpr>(E))
682 CGF.CGM.EmitExplicitCastExprType(ECE, &CGF);
683 switch (E->getCastKind()) {
685 // FIXME: Can this actually happen? We have no test coverage for it.
686 assert(isa<CXXDynamicCastExpr>(E) && "CK_Dynamic without a dynamic_cast?");
687 LValue LV = CGF.EmitCheckedLValue(E->getSubExpr(),
688 CodeGenFunction::TCK_Load);
689 // FIXME: Do we also need to handle property references here?
691 CGF.EmitDynamicCast(LV.getAddress(CGF), cast<CXXDynamicCastExpr>(E));
693 CGF.CGM.ErrorUnsupported(E, "non-simple lvalue dynamic_cast");
695 if (!Dest.isIgnored())
696 CGF.CGM.ErrorUnsupported(E, "lvalue dynamic_cast with a destination");
701 // Evaluate even if the destination is ignored.
702 if (Dest.isIgnored()) {
703 CGF.EmitAnyExpr(E->getSubExpr(), AggValueSlot::ignored(),
704 /*ignoreResult=*/true);
708 // GCC union extension
709 QualType Ty = E->getSubExpr()->getType();
711 Builder.CreateElementBitCast(Dest.getAddress(), CGF.ConvertType(Ty));
712 EmitInitializationToLValue(E->getSubExpr(),
713 CGF.MakeAddrLValue(CastPtr, Ty));
717 case CK_LValueToRValueBitCast: {
718 if (Dest.isIgnored()) {
719 CGF.EmitAnyExpr(E->getSubExpr(), AggValueSlot::ignored(),
720 /*ignoreResult=*/true);
724 LValue SourceLV = CGF.EmitLValue(E->getSubExpr());
725 Address SourceAddress =
726 Builder.CreateElementBitCast(SourceLV.getAddress(CGF), CGF.Int8Ty);
727 Address DestAddress =
728 Builder.CreateElementBitCast(Dest.getAddress(), CGF.Int8Ty);
729 llvm::Value *SizeVal = llvm::ConstantInt::get(
731 CGF.getContext().getTypeSizeInChars(E->getType()).getQuantity());
732 Builder.CreateMemCpy(DestAddress, SourceAddress, SizeVal);
736 case CK_DerivedToBase:
737 case CK_BaseToDerived:
738 case CK_UncheckedDerivedToBase: {
739 llvm_unreachable("cannot perform hierarchy conversion in EmitAggExpr: "
740 "should have been unpacked before we got here");
743 case CK_NonAtomicToAtomic:
744 case CK_AtomicToNonAtomic: {
745 bool isToAtomic = (E->getCastKind() == CK_NonAtomicToAtomic);
747 // Determine the atomic and value types.
748 QualType atomicType = E->getSubExpr()->getType();
749 QualType valueType = E->getType();
750 if (isToAtomic) std::swap(atomicType, valueType);
752 assert(atomicType->isAtomicType());
753 assert(CGF.getContext().hasSameUnqualifiedType(valueType,
754 atomicType->castAs<AtomicType>()->getValueType()));
756 // Just recurse normally if we're ignoring the result or the
757 // atomic type doesn't change representation.
758 if (Dest.isIgnored() || !CGF.CGM.isPaddedAtomicType(atomicType)) {
759 return Visit(E->getSubExpr());
762 CastKind peepholeTarget =
763 (isToAtomic ? CK_AtomicToNonAtomic : CK_NonAtomicToAtomic);
765 // These two cases are reverses of each other; try to peephole them.
766 if (Expr *op = findPeephole(E->getSubExpr(), peepholeTarget)) {
767 assert(CGF.getContext().hasSameUnqualifiedType(op->getType(),
769 "peephole significantly changed types?");
773 // If we're converting an r-value of non-atomic type to an r-value
774 // of atomic type, just emit directly into the relevant sub-object.
776 AggValueSlot valueDest = Dest;
777 if (!valueDest.isIgnored() && CGF.CGM.isPaddedAtomicType(atomicType)) {
778 // Zero-initialize. (Strictly speaking, we only need to initialize
779 // the padding at the end, but this is simpler.)
780 if (!Dest.isZeroed())
781 CGF.EmitNullInitialization(Dest.getAddress(), atomicType);
783 // Build a GEP to refer to the subobject.
785 CGF.Builder.CreateStructGEP(valueDest.getAddress(), 0);
786 valueDest = AggValueSlot::forAddr(valueAddr,
787 valueDest.getQualifiers(),
788 valueDest.isExternallyDestructed(),
789 valueDest.requiresGCollection(),
790 valueDest.isPotentiallyAliased(),
791 AggValueSlot::DoesNotOverlap,
792 AggValueSlot::IsZeroed);
795 CGF.EmitAggExpr(E->getSubExpr(), valueDest);
799 // Otherwise, we're converting an atomic type to a non-atomic type.
800 // Make an atomic temporary, emit into that, and then copy the value out.
801 AggValueSlot atomicSlot =
802 CGF.CreateAggTemp(atomicType, "atomic-to-nonatomic.temp");
803 CGF.EmitAggExpr(E->getSubExpr(), atomicSlot);
805 Address valueAddr = Builder.CreateStructGEP(atomicSlot.getAddress(), 0);
806 RValue rvalue = RValue::getAggregate(valueAddr, atomicSlot.isVolatile());
807 return EmitFinalDestCopy(valueType, rvalue);
809 case CK_AddressSpaceConversion:
810 return Visit(E->getSubExpr());
812 case CK_LValueToRValue:
813 // If we're loading from a volatile type, force the destination
815 if (E->getSubExpr()->getType().isVolatileQualified()) {
816 EnsureDest(E->getType());
817 return Visit(E->getSubExpr());
824 case CK_UserDefinedConversion:
825 case CK_ConstructorConversion:
826 assert(CGF.getContext().hasSameUnqualifiedType(E->getSubExpr()->getType(),
828 "Implicit cast types must be compatible");
829 Visit(E->getSubExpr());
832 case CK_LValueBitCast:
833 llvm_unreachable("should not be emitting lvalue bitcast as rvalue");
837 case CK_ArrayToPointerDecay:
838 case CK_FunctionToPointerDecay:
839 case CK_NullToPointer:
840 case CK_NullToMemberPointer:
841 case CK_BaseToDerivedMemberPointer:
842 case CK_DerivedToBaseMemberPointer:
843 case CK_MemberPointerToBoolean:
844 case CK_ReinterpretMemberPointer:
845 case CK_IntegralToPointer:
846 case CK_PointerToIntegral:
847 case CK_PointerToBoolean:
850 case CK_IntegralCast:
851 case CK_BooleanToSignedIntegral:
852 case CK_IntegralToBoolean:
853 case CK_IntegralToFloating:
854 case CK_FloatingToIntegral:
855 case CK_FloatingToBoolean:
856 case CK_FloatingCast:
857 case CK_CPointerToObjCPointerCast:
858 case CK_BlockPointerToObjCPointerCast:
859 case CK_AnyPointerToBlockPointerCast:
860 case CK_ObjCObjectLValueCast:
861 case CK_FloatingRealToComplex:
862 case CK_FloatingComplexToReal:
863 case CK_FloatingComplexToBoolean:
864 case CK_FloatingComplexCast:
865 case CK_FloatingComplexToIntegralComplex:
866 case CK_IntegralRealToComplex:
867 case CK_IntegralComplexToReal:
868 case CK_IntegralComplexToBoolean:
869 case CK_IntegralComplexCast:
870 case CK_IntegralComplexToFloatingComplex:
871 case CK_ARCProduceObject:
872 case CK_ARCConsumeObject:
873 case CK_ARCReclaimReturnedObject:
874 case CK_ARCExtendBlockObject:
875 case CK_CopyAndAutoreleaseBlockObject:
876 case CK_BuiltinFnToFnPtr:
877 case CK_ZeroToOCLOpaqueType:
879 case CK_IntToOCLSampler:
880 case CK_FixedPointCast:
881 case CK_FixedPointToBoolean:
882 case CK_FixedPointToIntegral:
883 case CK_IntegralToFixedPoint:
884 llvm_unreachable("cast kind invalid for aggregate types");
888 void AggExprEmitter::VisitCallExpr(const CallExpr *E) {
889 if (E->getCallReturnType(CGF.getContext())->isReferenceType()) {
890 EmitAggLoadOfLValue(E);
894 withReturnValueSlot(E, [&](ReturnValueSlot Slot) {
895 return CGF.EmitCallExpr(E, Slot);
899 void AggExprEmitter::VisitObjCMessageExpr(ObjCMessageExpr *E) {
900 withReturnValueSlot(E, [&](ReturnValueSlot Slot) {
901 return CGF.EmitObjCMessageExpr(E, Slot);
905 void AggExprEmitter::VisitBinComma(const BinaryOperator *E) {
906 CGF.EmitIgnoredExpr(E->getLHS());
910 void AggExprEmitter::VisitStmtExpr(const StmtExpr *E) {
911 CodeGenFunction::StmtExprEvaluation eval(CGF);
912 CGF.EmitCompoundStmt(*E->getSubStmt(), true, Dest);
921 static llvm::Value *EmitCompare(CGBuilderTy &Builder, CodeGenFunction &CGF,
922 const BinaryOperator *E, llvm::Value *LHS,
923 llvm::Value *RHS, CompareKind Kind,
924 const char *NameSuffix = "") {
925 QualType ArgTy = E->getLHS()->getType();
926 if (const ComplexType *CT = ArgTy->getAs<ComplexType>())
927 ArgTy = CT->getElementType();
929 if (const auto *MPT = ArgTy->getAs<MemberPointerType>()) {
930 assert(Kind == CK_Equal &&
931 "member pointers may only be compared for equality");
932 return CGF.CGM.getCXXABI().EmitMemberPointerComparison(
933 CGF, LHS, RHS, MPT, /*IsInequality*/ false);
936 // Compute the comparison instructions for the specified comparison kind.
939 llvm::CmpInst::Predicate FCmp;
940 llvm::CmpInst::Predicate SCmp;
941 llvm::CmpInst::Predicate UCmp;
943 CmpInstInfo InstInfo = [&]() -> CmpInstInfo {
944 using FI = llvm::FCmpInst;
945 using II = llvm::ICmpInst;
948 return {"cmp.lt", FI::FCMP_OLT, II::ICMP_SLT, II::ICMP_ULT};
950 return {"cmp.gt", FI::FCMP_OGT, II::ICMP_SGT, II::ICMP_UGT};
952 return {"cmp.eq", FI::FCMP_OEQ, II::ICMP_EQ, II::ICMP_EQ};
954 llvm_unreachable("Unrecognised CompareKind enum");
957 if (ArgTy->hasFloatingRepresentation())
958 return Builder.CreateFCmp(InstInfo.FCmp, LHS, RHS,
959 llvm::Twine(InstInfo.Name) + NameSuffix);
960 if (ArgTy->isIntegralOrEnumerationType() || ArgTy->isPointerType()) {
962 ArgTy->hasSignedIntegerRepresentation() ? InstInfo.SCmp : InstInfo.UCmp;
963 return Builder.CreateICmp(Inst, LHS, RHS,
964 llvm::Twine(InstInfo.Name) + NameSuffix);
967 llvm_unreachable("unsupported aggregate binary expression should have "
968 "already been handled");
971 void AggExprEmitter::VisitBinCmp(const BinaryOperator *E) {
972 using llvm::BasicBlock;
975 assert(CGF.getContext().hasSameType(E->getLHS()->getType(),
976 E->getRHS()->getType()));
977 const ComparisonCategoryInfo &CmpInfo =
978 CGF.getContext().CompCategories.getInfoForType(E->getType());
979 assert(CmpInfo.Record->isTriviallyCopyable() &&
980 "cannot copy non-trivially copyable aggregate");
982 QualType ArgTy = E->getLHS()->getType();
984 if (!ArgTy->isIntegralOrEnumerationType() && !ArgTy->isRealFloatingType() &&
985 !ArgTy->isNullPtrType() && !ArgTy->isPointerType() &&
986 !ArgTy->isMemberPointerType() && !ArgTy->isAnyComplexType()) {
987 return CGF.ErrorUnsupported(E, "aggregate three-way comparison");
989 bool IsComplex = ArgTy->isAnyComplexType();
991 // Evaluate the operands to the expression and extract their values.
992 auto EmitOperand = [&](Expr *E) -> std::pair<Value *, Value *> {
993 RValue RV = CGF.EmitAnyExpr(E);
995 return {RV.getScalarVal(), nullptr};
996 if (RV.isAggregate())
997 return {RV.getAggregatePointer(), nullptr};
998 assert(RV.isComplex());
999 return RV.getComplexVal();
1001 auto LHSValues = EmitOperand(E->getLHS()),
1002 RHSValues = EmitOperand(E->getRHS());
1004 auto EmitCmp = [&](CompareKind K) {
1005 Value *Cmp = EmitCompare(Builder, CGF, E, LHSValues.first, RHSValues.first,
1006 K, IsComplex ? ".r" : "");
1009 assert(K == CompareKind::CK_Equal);
1010 Value *CmpImag = EmitCompare(Builder, CGF, E, LHSValues.second,
1011 RHSValues.second, K, ".i");
1012 return Builder.CreateAnd(Cmp, CmpImag, "and.eq");
1014 auto EmitCmpRes = [&](const ComparisonCategoryInfo::ValueInfo *VInfo) {
1015 return Builder.getInt(VInfo->getIntValue());
1019 if (ArgTy->isNullPtrType()) {
1020 Select = EmitCmpRes(CmpInfo.getEqualOrEquiv());
1021 } else if (!CmpInfo.isPartial()) {
1023 Builder.CreateSelect(EmitCmp(CK_Less), EmitCmpRes(CmpInfo.getLess()),
1024 EmitCmpRes(CmpInfo.getGreater()), "sel.lt");
1025 Select = Builder.CreateSelect(EmitCmp(CK_Equal),
1026 EmitCmpRes(CmpInfo.getEqualOrEquiv()),
1027 SelectOne, "sel.eq");
1029 Value *SelectEq = Builder.CreateSelect(
1030 EmitCmp(CK_Equal), EmitCmpRes(CmpInfo.getEqualOrEquiv()),
1031 EmitCmpRes(CmpInfo.getUnordered()), "sel.eq");
1032 Value *SelectGT = Builder.CreateSelect(EmitCmp(CK_Greater),
1033 EmitCmpRes(CmpInfo.getGreater()),
1034 SelectEq, "sel.gt");
1035 Select = Builder.CreateSelect(
1036 EmitCmp(CK_Less), EmitCmpRes(CmpInfo.getLess()), SelectGT, "sel.lt");
1038 // Create the return value in the destination slot.
1039 EnsureDest(E->getType());
1040 LValue DestLV = CGF.MakeAddrLValue(Dest.getAddress(), E->getType());
1042 // Emit the address of the first (and only) field in the comparison category
1043 // type, and initialize it from the constant integer value selected above.
1044 LValue FieldLV = CGF.EmitLValueForFieldInitialization(
1045 DestLV, *CmpInfo.Record->field_begin());
1046 CGF.EmitStoreThroughLValue(RValue::get(Select), FieldLV, /*IsInit*/ true);
1048 // All done! The result is in the Dest slot.
1051 void AggExprEmitter::VisitBinaryOperator(const BinaryOperator *E) {
1052 if (E->getOpcode() == BO_PtrMemD || E->getOpcode() == BO_PtrMemI)
1053 VisitPointerToDataMemberBinaryOperator(E);
1055 CGF.ErrorUnsupported(E, "aggregate binary expression");
1058 void AggExprEmitter::VisitPointerToDataMemberBinaryOperator(
1059 const BinaryOperator *E) {
1060 LValue LV = CGF.EmitPointerToDataMemberBinaryExpr(E);
1061 EmitFinalDestCopy(E->getType(), LV);
1064 /// Is the value of the given expression possibly a reference to or
1065 /// into a __block variable?
1066 static bool isBlockVarRef(const Expr *E) {
1067 // Make sure we look through parens.
1068 E = E->IgnoreParens();
1070 // Check for a direct reference to a __block variable.
1071 if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E)) {
1072 const VarDecl *var = dyn_cast<VarDecl>(DRE->getDecl());
1073 return (var && var->hasAttr<BlocksAttr>());
1076 // More complicated stuff.
1078 // Binary operators.
1079 if (const BinaryOperator *op = dyn_cast<BinaryOperator>(E)) {
1080 // For an assignment or pointer-to-member operation, just care
1082 if (op->isAssignmentOp() || op->isPtrMemOp())
1083 return isBlockVarRef(op->getLHS());
1085 // For a comma, just care about the RHS.
1086 if (op->getOpcode() == BO_Comma)
1087 return isBlockVarRef(op->getRHS());
1089 // FIXME: pointer arithmetic?
1092 // Check both sides of a conditional operator.
1093 } else if (const AbstractConditionalOperator *op
1094 = dyn_cast<AbstractConditionalOperator>(E)) {
1095 return isBlockVarRef(op->getTrueExpr())
1096 || isBlockVarRef(op->getFalseExpr());
1098 // OVEs are required to support BinaryConditionalOperators.
1099 } else if (const OpaqueValueExpr *op
1100 = dyn_cast<OpaqueValueExpr>(E)) {
1101 if (const Expr *src = op->getSourceExpr())
1102 return isBlockVarRef(src);
1104 // Casts are necessary to get things like (*(int*)&var) = foo().
1105 // We don't really care about the kind of cast here, except
1106 // we don't want to look through l2r casts, because it's okay
1107 // to get the *value* in a __block variable.
1108 } else if (const CastExpr *cast = dyn_cast<CastExpr>(E)) {
1109 if (cast->getCastKind() == CK_LValueToRValue)
1111 return isBlockVarRef(cast->getSubExpr());
1113 // Handle unary operators. Again, just aggressively look through
1114 // it, ignoring the operation.
1115 } else if (const UnaryOperator *uop = dyn_cast<UnaryOperator>(E)) {
1116 return isBlockVarRef(uop->getSubExpr());
1118 // Look into the base of a field access.
1119 } else if (const MemberExpr *mem = dyn_cast<MemberExpr>(E)) {
1120 return isBlockVarRef(mem->getBase());
1122 // Look into the base of a subscript.
1123 } else if (const ArraySubscriptExpr *sub = dyn_cast<ArraySubscriptExpr>(E)) {
1124 return isBlockVarRef(sub->getBase());
1130 void AggExprEmitter::VisitBinAssign(const BinaryOperator *E) {
1131 // For an assignment to work, the value on the right has
1132 // to be compatible with the value on the left.
1133 assert(CGF.getContext().hasSameUnqualifiedType(E->getLHS()->getType(),
1134 E->getRHS()->getType())
1135 && "Invalid assignment");
1137 // If the LHS might be a __block variable, and the RHS can
1138 // potentially cause a block copy, we need to evaluate the RHS first
1139 // so that the assignment goes the right place.
1140 // This is pretty semantically fragile.
1141 if (isBlockVarRef(E->getLHS()) &&
1142 E->getRHS()->HasSideEffects(CGF.getContext())) {
1143 // Ensure that we have a destination, and evaluate the RHS into that.
1144 EnsureDest(E->getRHS()->getType());
1147 // Now emit the LHS and copy into it.
1148 LValue LHS = CGF.EmitCheckedLValue(E->getLHS(), CodeGenFunction::TCK_Store);
1150 // That copy is an atomic copy if the LHS is atomic.
1151 if (LHS.getType()->isAtomicType() ||
1152 CGF.LValueIsSuitableForInlineAtomic(LHS)) {
1153 CGF.EmitAtomicStore(Dest.asRValue(), LHS, /*isInit*/ false);
1157 EmitCopy(E->getLHS()->getType(),
1158 AggValueSlot::forLValue(LHS, CGF, AggValueSlot::IsDestructed,
1159 needsGC(E->getLHS()->getType()),
1160 AggValueSlot::IsAliased,
1161 AggValueSlot::MayOverlap),
1166 LValue LHS = CGF.EmitLValue(E->getLHS());
1168 // If we have an atomic type, evaluate into the destination and then
1169 // do an atomic copy.
1170 if (LHS.getType()->isAtomicType() ||
1171 CGF.LValueIsSuitableForInlineAtomic(LHS)) {
1172 EnsureDest(E->getRHS()->getType());
1174 CGF.EmitAtomicStore(Dest.asRValue(), LHS, /*isInit*/ false);
1178 // Codegen the RHS so that it stores directly into the LHS.
1179 AggValueSlot LHSSlot = AggValueSlot::forLValue(
1180 LHS, CGF, AggValueSlot::IsDestructed, needsGC(E->getLHS()->getType()),
1181 AggValueSlot::IsAliased, AggValueSlot::MayOverlap);
1182 // A non-volatile aggregate destination might have volatile member.
1183 if (!LHSSlot.isVolatile() &&
1184 CGF.hasVolatileMember(E->getLHS()->getType()))
1185 LHSSlot.setVolatile(true);
1187 CGF.EmitAggExpr(E->getRHS(), LHSSlot);
1189 // Copy into the destination if the assignment isn't ignored.
1190 EmitFinalDestCopy(E->getType(), LHS);
1193 void AggExprEmitter::
1194 VisitAbstractConditionalOperator(const AbstractConditionalOperator *E) {
1195 llvm::BasicBlock *LHSBlock = CGF.createBasicBlock("cond.true");
1196 llvm::BasicBlock *RHSBlock = CGF.createBasicBlock("cond.false");
1197 llvm::BasicBlock *ContBlock = CGF.createBasicBlock("cond.end");
1199 // Bind the common expression if necessary.
1200 CodeGenFunction::OpaqueValueMapping binding(CGF, E);
1202 CodeGenFunction::ConditionalEvaluation eval(CGF);
1203 CGF.EmitBranchOnBoolExpr(E->getCond(), LHSBlock, RHSBlock,
1204 CGF.getProfileCount(E));
1206 // Save whether the destination's lifetime is externally managed.
1207 bool isExternallyDestructed = Dest.isExternallyDestructed();
1210 CGF.EmitBlock(LHSBlock);
1211 CGF.incrementProfileCounter(E);
1212 Visit(E->getTrueExpr());
1215 assert(CGF.HaveInsertPoint() && "expression evaluation ended with no IP!");
1216 CGF.Builder.CreateBr(ContBlock);
1218 // If the result of an agg expression is unused, then the emission
1219 // of the LHS might need to create a destination slot. That's fine
1220 // with us, and we can safely emit the RHS into the same slot, but
1221 // we shouldn't claim that it's already being destructed.
1222 Dest.setExternallyDestructed(isExternallyDestructed);
1225 CGF.EmitBlock(RHSBlock);
1226 Visit(E->getFalseExpr());
1229 CGF.EmitBlock(ContBlock);
1232 void AggExprEmitter::VisitChooseExpr(const ChooseExpr *CE) {
1233 Visit(CE->getChosenSubExpr());
1236 void AggExprEmitter::VisitVAArgExpr(VAArgExpr *VE) {
1237 Address ArgValue = Address::invalid();
1238 Address ArgPtr = CGF.EmitVAArg(VE, ArgValue);
1240 // If EmitVAArg fails, emit an error.
1241 if (!ArgPtr.isValid()) {
1242 CGF.ErrorUnsupported(VE, "aggregate va_arg expression");
1246 EmitFinalDestCopy(VE->getType(), CGF.MakeAddrLValue(ArgPtr, VE->getType()));
1249 void AggExprEmitter::VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E) {
1250 // Ensure that we have a slot, but if we already do, remember
1251 // whether it was externally destructed.
1252 bool wasExternallyDestructed = Dest.isExternallyDestructed();
1253 EnsureDest(E->getType());
1255 // We're going to push a destructor if there isn't already one.
1256 Dest.setExternallyDestructed();
1258 Visit(E->getSubExpr());
1260 // Push that destructor we promised.
1261 if (!wasExternallyDestructed)
1262 CGF.EmitCXXTemporary(E->getTemporary(), E->getType(), Dest.getAddress());
1266 AggExprEmitter::VisitCXXConstructExpr(const CXXConstructExpr *E) {
1267 AggValueSlot Slot = EnsureSlot(E->getType());
1268 CGF.EmitCXXConstructExpr(E, Slot);
1271 void AggExprEmitter::VisitCXXInheritedCtorInitExpr(
1272 const CXXInheritedCtorInitExpr *E) {
1273 AggValueSlot Slot = EnsureSlot(E->getType());
1274 CGF.EmitInheritedCXXConstructorCall(
1275 E->getConstructor(), E->constructsVBase(), Slot.getAddress(),
1276 E->inheritedFromVBase(), E);
1280 AggExprEmitter::VisitLambdaExpr(LambdaExpr *E) {
1281 AggValueSlot Slot = EnsureSlot(E->getType());
1282 LValue SlotLV = CGF.MakeAddrLValue(Slot.getAddress(), E->getType());
1284 // We'll need to enter cleanup scopes in case any of the element
1285 // initializers throws an exception.
1286 SmallVector<EHScopeStack::stable_iterator, 16> Cleanups;
1287 llvm::Instruction *CleanupDominator = nullptr;
1289 CXXRecordDecl::field_iterator CurField = E->getLambdaClass()->field_begin();
1290 for (LambdaExpr::const_capture_init_iterator i = E->capture_init_begin(),
1291 e = E->capture_init_end();
1292 i != e; ++i, ++CurField) {
1293 // Emit initialization
1294 LValue LV = CGF.EmitLValueForFieldInitialization(SlotLV, *CurField);
1295 if (CurField->hasCapturedVLAType()) {
1296 CGF.EmitLambdaVLACapture(CurField->getCapturedVLAType(), LV);
1300 EmitInitializationToLValue(*i, LV);
1302 // Push a destructor if necessary.
1303 if (QualType::DestructionKind DtorKind =
1304 CurField->getType().isDestructedType()) {
1305 assert(LV.isSimple());
1306 if (CGF.needsEHCleanup(DtorKind)) {
1307 if (!CleanupDominator)
1308 CleanupDominator = CGF.Builder.CreateAlignedLoad(
1310 llvm::Constant::getNullValue(CGF.Int8PtrTy),
1311 CharUnits::One()); // placeholder
1313 CGF.pushDestroy(EHCleanup, LV.getAddress(CGF), CurField->getType(),
1314 CGF.getDestroyer(DtorKind), false);
1315 Cleanups.push_back(CGF.EHStack.stable_begin());
1320 // Deactivate all the partial cleanups in reverse order, which
1321 // generally means popping them.
1322 for (unsigned i = Cleanups.size(); i != 0; --i)
1323 CGF.DeactivateCleanupBlock(Cleanups[i-1], CleanupDominator);
1325 // Destroy the placeholder if we made one.
1326 if (CleanupDominator)
1327 CleanupDominator->eraseFromParent();
1330 void AggExprEmitter::VisitExprWithCleanups(ExprWithCleanups *E) {
1331 CGF.enterFullExpression(E);
1332 CodeGenFunction::RunCleanupsScope cleanups(CGF);
1333 Visit(E->getSubExpr());
1336 void AggExprEmitter::VisitCXXScalarValueInitExpr(CXXScalarValueInitExpr *E) {
1337 QualType T = E->getType();
1338 AggValueSlot Slot = EnsureSlot(T);
1339 EmitNullInitializationToLValue(CGF.MakeAddrLValue(Slot.getAddress(), T));
1342 void AggExprEmitter::VisitImplicitValueInitExpr(ImplicitValueInitExpr *E) {
1343 QualType T = E->getType();
1344 AggValueSlot Slot = EnsureSlot(T);
1345 EmitNullInitializationToLValue(CGF.MakeAddrLValue(Slot.getAddress(), T));
1348 /// isSimpleZero - If emitting this value will obviously just cause a store of
1349 /// zero to memory, return true. This can return false if uncertain, so it just
1350 /// handles simple cases.
1351 static bool isSimpleZero(const Expr *E, CodeGenFunction &CGF) {
1352 E = E->IgnoreParens();
1355 if (const IntegerLiteral *IL = dyn_cast<IntegerLiteral>(E))
1356 return IL->getValue() == 0;
1358 if (const FloatingLiteral *FL = dyn_cast<FloatingLiteral>(E))
1359 return FL->getValue().isPosZero();
1361 if ((isa<ImplicitValueInitExpr>(E) || isa<CXXScalarValueInitExpr>(E)) &&
1362 CGF.getTypes().isZeroInitializable(E->getType()))
1364 // (int*)0 - Null pointer expressions.
1365 if (const CastExpr *ICE = dyn_cast<CastExpr>(E))
1366 return ICE->getCastKind() == CK_NullToPointer &&
1367 CGF.getTypes().isPointerZeroInitializable(E->getType()) &&
1368 !E->HasSideEffects(CGF.getContext());
1370 if (const CharacterLiteral *CL = dyn_cast<CharacterLiteral>(E))
1371 return CL->getValue() == 0;
1373 // Otherwise, hard case: conservatively return false.
1379 AggExprEmitter::EmitInitializationToLValue(Expr *E, LValue LV) {
1380 QualType type = LV.getType();
1381 // FIXME: Ignore result?
1382 // FIXME: Are initializers affected by volatile?
1383 if (Dest.isZeroed() && isSimpleZero(E, CGF)) {
1384 // Storing "i32 0" to a zero'd memory location is a noop.
1386 } else if (isa<ImplicitValueInitExpr>(E) || isa<CXXScalarValueInitExpr>(E)) {
1387 return EmitNullInitializationToLValue(LV);
1388 } else if (isa<NoInitExpr>(E)) {
1391 } else if (type->isReferenceType()) {
1392 RValue RV = CGF.EmitReferenceBindingToExpr(E);
1393 return CGF.EmitStoreThroughLValue(RV, LV);
1396 switch (CGF.getEvaluationKind(type)) {
1398 CGF.EmitComplexExprIntoLValue(E, LV, /*isInit*/ true);
1402 E, AggValueSlot::forLValue(LV, CGF, AggValueSlot::IsDestructed,
1403 AggValueSlot::DoesNotNeedGCBarriers,
1404 AggValueSlot::IsNotAliased,
1405 AggValueSlot::MayOverlap, Dest.isZeroed()));
1408 if (LV.isSimple()) {
1409 CGF.EmitScalarInit(E, /*D=*/nullptr, LV, /*Captured=*/false);
1411 CGF.EmitStoreThroughLValue(RValue::get(CGF.EmitScalarExpr(E)), LV);
1415 llvm_unreachable("bad evaluation kind");
1418 void AggExprEmitter::EmitNullInitializationToLValue(LValue lv) {
1419 QualType type = lv.getType();
1421 // If the destination slot is already zeroed out before the aggregate is
1422 // copied into it, we don't have to emit any zeros here.
1423 if (Dest.isZeroed() && CGF.getTypes().isZeroInitializable(type))
1426 if (CGF.hasScalarEvaluationKind(type)) {
1427 // For non-aggregates, we can store the appropriate null constant.
1428 llvm::Value *null = CGF.CGM.EmitNullConstant(type);
1429 // Note that the following is not equivalent to
1430 // EmitStoreThroughBitfieldLValue for ARC types.
1431 if (lv.isBitField()) {
1432 CGF.EmitStoreThroughBitfieldLValue(RValue::get(null), lv);
1434 assert(lv.isSimple());
1435 CGF.EmitStoreOfScalar(null, lv, /* isInitialization */ true);
1438 // There's a potential optimization opportunity in combining
1439 // memsets; that would be easy for arrays, but relatively
1440 // difficult for structures with the current code.
1441 CGF.EmitNullInitialization(lv.getAddress(CGF), lv.getType());
1445 void AggExprEmitter::VisitInitListExpr(InitListExpr *E) {
1447 // FIXME: Assess perf here? Figure out what cases are worth optimizing here
1448 // (Length of globals? Chunks of zeroed-out space?).
1450 // If we can, prefer a copy from a global; this is a lot less code for long
1451 // globals, and it's easier for the current optimizers to analyze.
1452 if (llvm::Constant* C = CGF.CGM.EmitConstantExpr(E, E->getType(), &CGF)) {
1453 llvm::GlobalVariable* GV =
1454 new llvm::GlobalVariable(CGF.CGM.getModule(), C->getType(), true,
1455 llvm::GlobalValue::InternalLinkage, C, "");
1456 EmitFinalDestCopy(E->getType(), CGF.MakeAddrLValue(GV, E->getType()));
1460 if (E->hadArrayRangeDesignator())
1461 CGF.ErrorUnsupported(E, "GNU array range designator extension");
1463 if (E->isTransparent())
1464 return Visit(E->getInit(0));
1466 AggValueSlot Dest = EnsureSlot(E->getType());
1468 LValue DestLV = CGF.MakeAddrLValue(Dest.getAddress(), E->getType());
1470 // Handle initialization of an array.
1471 if (E->getType()->isArrayType()) {
1472 auto AType = cast<llvm::ArrayType>(Dest.getAddress().getElementType());
1473 EmitArrayInit(Dest.getAddress(), AType, E->getType(), E);
1477 assert(E->getType()->isRecordType() && "Only support structs/unions here!");
1479 // Do struct initialization; this code just sets each individual member
1480 // to the approprate value. This makes bitfield support automatic;
1481 // the disadvantage is that the generated code is more difficult for
1482 // the optimizer, especially with bitfields.
1483 unsigned NumInitElements = E->getNumInits();
1484 RecordDecl *record = E->getType()->castAs<RecordType>()->getDecl();
1486 // We'll need to enter cleanup scopes in case any of the element
1487 // initializers throws an exception.
1488 SmallVector<EHScopeStack::stable_iterator, 16> cleanups;
1489 llvm::Instruction *cleanupDominator = nullptr;
1490 auto addCleanup = [&](const EHScopeStack::stable_iterator &cleanup) {
1491 cleanups.push_back(cleanup);
1492 if (!cleanupDominator) // create placeholder once needed
1493 cleanupDominator = CGF.Builder.CreateAlignedLoad(
1494 CGF.Int8Ty, llvm::Constant::getNullValue(CGF.Int8PtrTy),
1498 unsigned curInitIndex = 0;
1500 // Emit initialization of base classes.
1501 if (auto *CXXRD = dyn_cast<CXXRecordDecl>(record)) {
1502 assert(E->getNumInits() >= CXXRD->getNumBases() &&
1503 "missing initializer for base class");
1504 for (auto &Base : CXXRD->bases()) {
1505 assert(!Base.isVirtual() && "should not see vbases here");
1506 auto *BaseRD = Base.getType()->getAsCXXRecordDecl();
1507 Address V = CGF.GetAddressOfDirectBaseInCompleteClass(
1508 Dest.getAddress(), CXXRD, BaseRD,
1509 /*isBaseVirtual*/ false);
1510 AggValueSlot AggSlot = AggValueSlot::forAddr(
1512 AggValueSlot::IsDestructed,
1513 AggValueSlot::DoesNotNeedGCBarriers,
1514 AggValueSlot::IsNotAliased,
1515 CGF.getOverlapForBaseInit(CXXRD, BaseRD, Base.isVirtual()));
1516 CGF.EmitAggExpr(E->getInit(curInitIndex++), AggSlot);
1518 if (QualType::DestructionKind dtorKind =
1519 Base.getType().isDestructedType()) {
1520 CGF.pushDestroy(dtorKind, V, Base.getType());
1521 addCleanup(CGF.EHStack.stable_begin());
1526 // Prepare a 'this' for CXXDefaultInitExprs.
1527 CodeGenFunction::FieldConstructionScope FCS(CGF, Dest.getAddress());
1529 if (record->isUnion()) {
1530 // Only initialize one field of a union. The field itself is
1531 // specified by the initializer list.
1532 if (!E->getInitializedFieldInUnion()) {
1533 // Empty union; we have nothing to do.
1536 // Make sure that it's really an empty and not a failure of
1537 // semantic analysis.
1538 for (const auto *Field : record->fields())
1539 assert(Field->isUnnamedBitfield() && "Only unnamed bitfields allowed");
1544 // FIXME: volatility
1545 FieldDecl *Field = E->getInitializedFieldInUnion();
1547 LValue FieldLoc = CGF.EmitLValueForFieldInitialization(DestLV, Field);
1548 if (NumInitElements) {
1549 // Store the initializer into the field
1550 EmitInitializationToLValue(E->getInit(0), FieldLoc);
1552 // Default-initialize to null.
1553 EmitNullInitializationToLValue(FieldLoc);
1559 // Here we iterate over the fields; this makes it simpler to both
1560 // default-initialize fields and skip over unnamed fields.
1561 for (const auto *field : record->fields()) {
1562 // We're done once we hit the flexible array member.
1563 if (field->getType()->isIncompleteArrayType())
1566 // Always skip anonymous bitfields.
1567 if (field->isUnnamedBitfield())
1570 // We're done if we reach the end of the explicit initializers, we
1571 // have a zeroed object, and the rest of the fields are
1572 // zero-initializable.
1573 if (curInitIndex == NumInitElements && Dest.isZeroed() &&
1574 CGF.getTypes().isZeroInitializable(E->getType()))
1578 LValue LV = CGF.EmitLValueForFieldInitialization(DestLV, field);
1579 // We never generate write-barries for initialized fields.
1582 if (curInitIndex < NumInitElements) {
1583 // Store the initializer into the field.
1584 EmitInitializationToLValue(E->getInit(curInitIndex++), LV);
1586 // We're out of initializers; default-initialize to null
1587 EmitNullInitializationToLValue(LV);
1590 // Push a destructor if necessary.
1591 // FIXME: if we have an array of structures, all explicitly
1592 // initialized, we can end up pushing a linear number of cleanups.
1593 bool pushedCleanup = false;
1594 if (QualType::DestructionKind dtorKind
1595 = field->getType().isDestructedType()) {
1596 assert(LV.isSimple());
1597 if (CGF.needsEHCleanup(dtorKind)) {
1598 CGF.pushDestroy(EHCleanup, LV.getAddress(CGF), field->getType(),
1599 CGF.getDestroyer(dtorKind), false);
1600 addCleanup(CGF.EHStack.stable_begin());
1601 pushedCleanup = true;
1605 // If the GEP didn't get used because of a dead zero init or something
1606 // else, clean it up for -O0 builds and general tidiness.
1607 if (!pushedCleanup && LV.isSimple())
1608 if (llvm::GetElementPtrInst *GEP =
1609 dyn_cast<llvm::GetElementPtrInst>(LV.getPointer(CGF)))
1610 if (GEP->use_empty())
1611 GEP->eraseFromParent();
1614 // Deactivate all the partial cleanups in reverse order, which
1615 // generally means popping them.
1616 assert((cleanupDominator || cleanups.empty()) &&
1617 "Missing cleanupDominator before deactivating cleanup blocks");
1618 for (unsigned i = cleanups.size(); i != 0; --i)
1619 CGF.DeactivateCleanupBlock(cleanups[i-1], cleanupDominator);
1621 // Destroy the placeholder if we made one.
1622 if (cleanupDominator)
1623 cleanupDominator->eraseFromParent();
1626 void AggExprEmitter::VisitArrayInitLoopExpr(const ArrayInitLoopExpr *E,
1627 llvm::Value *outerBegin) {
1628 // Emit the common subexpression.
1629 CodeGenFunction::OpaqueValueMapping binding(CGF, E->getCommonExpr());
1631 Address destPtr = EnsureSlot(E->getType()).getAddress();
1632 uint64_t numElements = E->getArraySize().getZExtValue();
1637 // destPtr is an array*. Construct an elementType* by drilling down a level.
1638 llvm::Value *zero = llvm::ConstantInt::get(CGF.SizeTy, 0);
1639 llvm::Value *indices[] = {zero, zero};
1640 llvm::Value *begin = Builder.CreateInBoundsGEP(destPtr.getPointer(), indices,
1643 // Prepare to special-case multidimensional array initialization: we avoid
1644 // emitting multiple destructor loops in that case.
1647 ArrayInitLoopExpr *InnerLoop = dyn_cast<ArrayInitLoopExpr>(E->getSubExpr());
1649 QualType elementType =
1650 CGF.getContext().getAsArrayType(E->getType())->getElementType();
1651 CharUnits elementSize = CGF.getContext().getTypeSizeInChars(elementType);
1652 CharUnits elementAlign =
1653 destPtr.getAlignment().alignmentOfArrayElement(elementSize);
1655 llvm::BasicBlock *entryBB = Builder.GetInsertBlock();
1656 llvm::BasicBlock *bodyBB = CGF.createBasicBlock("arrayinit.body");
1658 // Jump into the body.
1659 CGF.EmitBlock(bodyBB);
1660 llvm::PHINode *index =
1661 Builder.CreatePHI(zero->getType(), 2, "arrayinit.index");
1662 index->addIncoming(zero, entryBB);
1663 llvm::Value *element = Builder.CreateInBoundsGEP(begin, index);
1665 // Prepare for a cleanup.
1666 QualType::DestructionKind dtorKind = elementType.isDestructedType();
1667 EHScopeStack::stable_iterator cleanup;
1668 if (CGF.needsEHCleanup(dtorKind) && !InnerLoop) {
1669 if (outerBegin->getType() != element->getType())
1670 outerBegin = Builder.CreateBitCast(outerBegin, element->getType());
1671 CGF.pushRegularPartialArrayCleanup(outerBegin, element, elementType,
1673 CGF.getDestroyer(dtorKind));
1674 cleanup = CGF.EHStack.stable_begin();
1676 dtorKind = QualType::DK_none;
1679 // Emit the actual filler expression.
1681 // Temporaries created in an array initialization loop are destroyed
1682 // at the end of each iteration.
1683 CodeGenFunction::RunCleanupsScope CleanupsScope(CGF);
1684 CodeGenFunction::ArrayInitLoopExprScope Scope(CGF, index);
1686 CGF.MakeAddrLValue(Address(element, elementAlign), elementType);
1689 // If the subexpression is an ArrayInitLoopExpr, share its cleanup.
1690 auto elementSlot = AggValueSlot::forLValue(
1691 elementLV, CGF, AggValueSlot::IsDestructed,
1692 AggValueSlot::DoesNotNeedGCBarriers, AggValueSlot::IsNotAliased,
1693 AggValueSlot::DoesNotOverlap);
1694 AggExprEmitter(CGF, elementSlot, false)
1695 .VisitArrayInitLoopExpr(InnerLoop, outerBegin);
1697 EmitInitializationToLValue(E->getSubExpr(), elementLV);
1700 // Move on to the next element.
1701 llvm::Value *nextIndex = Builder.CreateNUWAdd(
1702 index, llvm::ConstantInt::get(CGF.SizeTy, 1), "arrayinit.next");
1703 index->addIncoming(nextIndex, Builder.GetInsertBlock());
1705 // Leave the loop if we're done.
1706 llvm::Value *done = Builder.CreateICmpEQ(
1707 nextIndex, llvm::ConstantInt::get(CGF.SizeTy, numElements),
1709 llvm::BasicBlock *endBB = CGF.createBasicBlock("arrayinit.end");
1710 Builder.CreateCondBr(done, endBB, bodyBB);
1712 CGF.EmitBlock(endBB);
1714 // Leave the partial-array cleanup if we entered one.
1716 CGF.DeactivateCleanupBlock(cleanup, index);
1719 void AggExprEmitter::VisitDesignatedInitUpdateExpr(DesignatedInitUpdateExpr *E) {
1720 AggValueSlot Dest = EnsureSlot(E->getType());
1722 LValue DestLV = CGF.MakeAddrLValue(Dest.getAddress(), E->getType());
1723 EmitInitializationToLValue(E->getBase(), DestLV);
1724 VisitInitListExpr(E->getUpdater());
1727 //===----------------------------------------------------------------------===//
1728 // Entry Points into this File
1729 //===----------------------------------------------------------------------===//
1731 /// GetNumNonZeroBytesInInit - Get an approximate count of the number of
1732 /// non-zero bytes that will be stored when outputting the initializer for the
1733 /// specified initializer expression.
1734 static CharUnits GetNumNonZeroBytesInInit(const Expr *E, CodeGenFunction &CGF) {
1735 E = E->IgnoreParens();
1737 // 0 and 0.0 won't require any non-zero stores!
1738 if (isSimpleZero(E, CGF)) return CharUnits::Zero();
1740 // If this is an initlist expr, sum up the size of sizes of the (present)
1741 // elements. If this is something weird, assume the whole thing is non-zero.
1742 const InitListExpr *ILE = dyn_cast<InitListExpr>(E);
1743 while (ILE && ILE->isTransparent())
1744 ILE = dyn_cast<InitListExpr>(ILE->getInit(0));
1745 if (!ILE || !CGF.getTypes().isZeroInitializable(ILE->getType()))
1746 return CGF.getContext().getTypeSizeInChars(E->getType());
1748 // InitListExprs for structs have to be handled carefully. If there are
1749 // reference members, we need to consider the size of the reference, not the
1750 // referencee. InitListExprs for unions and arrays can't have references.
1751 if (const RecordType *RT = E->getType()->getAs<RecordType>()) {
1752 if (!RT->isUnionType()) {
1753 RecordDecl *SD = RT->getDecl();
1754 CharUnits NumNonZeroBytes = CharUnits::Zero();
1756 unsigned ILEElement = 0;
1757 if (auto *CXXRD = dyn_cast<CXXRecordDecl>(SD))
1758 while (ILEElement != CXXRD->getNumBases())
1760 GetNumNonZeroBytesInInit(ILE->getInit(ILEElement++), CGF);
1761 for (const auto *Field : SD->fields()) {
1762 // We're done once we hit the flexible array member or run out of
1763 // InitListExpr elements.
1764 if (Field->getType()->isIncompleteArrayType() ||
1765 ILEElement == ILE->getNumInits())
1767 if (Field->isUnnamedBitfield())
1770 const Expr *E = ILE->getInit(ILEElement++);
1772 // Reference values are always non-null and have the width of a pointer.
1773 if (Field->getType()->isReferenceType())
1774 NumNonZeroBytes += CGF.getContext().toCharUnitsFromBits(
1775 CGF.getTarget().getPointerWidth(0));
1777 NumNonZeroBytes += GetNumNonZeroBytesInInit(E, CGF);
1780 return NumNonZeroBytes;
1785 CharUnits NumNonZeroBytes = CharUnits::Zero();
1786 for (unsigned i = 0, e = ILE->getNumInits(); i != e; ++i)
1787 NumNonZeroBytes += GetNumNonZeroBytesInInit(ILE->getInit(i), CGF);
1788 return NumNonZeroBytes;
1791 /// CheckAggExprForMemSetUse - If the initializer is large and has a lot of
1792 /// zeros in it, emit a memset and avoid storing the individual zeros.
1794 static void CheckAggExprForMemSetUse(AggValueSlot &Slot, const Expr *E,
1795 CodeGenFunction &CGF) {
1796 // If the slot is already known to be zeroed, nothing to do. Don't mess with
1798 if (Slot.isZeroed() || Slot.isVolatile() || !Slot.getAddress().isValid())
1801 // C++ objects with a user-declared constructor don't need zero'ing.
1802 if (CGF.getLangOpts().CPlusPlus)
1803 if (const RecordType *RT = CGF.getContext()
1804 .getBaseElementType(E->getType())->getAs<RecordType>()) {
1805 const CXXRecordDecl *RD = cast<CXXRecordDecl>(RT->getDecl());
1806 if (RD->hasUserDeclaredConstructor())
1810 // If the type is 16-bytes or smaller, prefer individual stores over memset.
1811 CharUnits Size = Slot.getPreferredSize(CGF.getContext(), E->getType());
1812 if (Size <= CharUnits::fromQuantity(16))
1815 // Check to see if over 3/4 of the initializer are known to be zero. If so,
1816 // we prefer to emit memset + individual stores for the rest.
1817 CharUnits NumNonZeroBytes = GetNumNonZeroBytesInInit(E, CGF);
1818 if (NumNonZeroBytes*4 > Size)
1821 // Okay, it seems like a good idea to use an initial memset, emit the call.
1822 llvm::Constant *SizeVal = CGF.Builder.getInt64(Size.getQuantity());
1824 Address Loc = Slot.getAddress();
1825 Loc = CGF.Builder.CreateElementBitCast(Loc, CGF.Int8Ty);
1826 CGF.Builder.CreateMemSet(Loc, CGF.Builder.getInt8(0), SizeVal, false);
1828 // Tell the AggExprEmitter that the slot is known zero.
1835 /// EmitAggExpr - Emit the computation of the specified expression of aggregate
1836 /// type. The result is computed into DestPtr. Note that if DestPtr is null,
1837 /// the value of the aggregate expression is not needed. If VolatileDest is
1838 /// true, DestPtr cannot be 0.
1839 void CodeGenFunction::EmitAggExpr(const Expr *E, AggValueSlot Slot) {
1840 assert(E && hasAggregateEvaluationKind(E->getType()) &&
1841 "Invalid aggregate expression to emit");
1842 assert((Slot.getAddress().isValid() || Slot.isIgnored()) &&
1843 "slot has bits but no address");
1845 // Optimize the slot if possible.
1846 CheckAggExprForMemSetUse(Slot, E, *this);
1848 AggExprEmitter(*this, Slot, Slot.isIgnored()).Visit(const_cast<Expr*>(E));
1851 LValue CodeGenFunction::EmitAggExprToLValue(const Expr *E) {
1852 assert(hasAggregateEvaluationKind(E->getType()) && "Invalid argument!");
1853 Address Temp = CreateMemTemp(E->getType());
1854 LValue LV = MakeAddrLValue(Temp, E->getType());
1855 EmitAggExpr(E, AggValueSlot::forLValue(
1856 LV, *this, AggValueSlot::IsNotDestructed,
1857 AggValueSlot::DoesNotNeedGCBarriers,
1858 AggValueSlot::IsNotAliased, AggValueSlot::DoesNotOverlap));
1862 AggValueSlot::Overlap_t
1863 CodeGenFunction::getOverlapForFieldInit(const FieldDecl *FD) {
1864 if (!FD->hasAttr<NoUniqueAddressAttr>() || !FD->getType()->isRecordType())
1865 return AggValueSlot::DoesNotOverlap;
1867 // If the field lies entirely within the enclosing class's nvsize, its tail
1868 // padding cannot overlap any already-initialized object. (The only subobjects
1869 // with greater addresses that might already be initialized are vbases.)
1870 const RecordDecl *ClassRD = FD->getParent();
1871 const ASTRecordLayout &Layout = getContext().getASTRecordLayout(ClassRD);
1872 if (Layout.getFieldOffset(FD->getFieldIndex()) +
1873 getContext().getTypeSize(FD->getType()) <=
1874 (uint64_t)getContext().toBits(Layout.getNonVirtualSize()))
1875 return AggValueSlot::DoesNotOverlap;
1877 // The tail padding may contain values we need to preserve.
1878 return AggValueSlot::MayOverlap;
1881 AggValueSlot::Overlap_t CodeGenFunction::getOverlapForBaseInit(
1882 const CXXRecordDecl *RD, const CXXRecordDecl *BaseRD, bool IsVirtual) {
1883 // If the most-derived object is a field declared with [[no_unique_address]],
1884 // the tail padding of any virtual base could be reused for other subobjects
1885 // of that field's class.
1887 return AggValueSlot::MayOverlap;
1889 // If the base class is laid out entirely within the nvsize of the derived
1890 // class, its tail padding cannot yet be initialized, so we can issue
1891 // stores at the full width of the base class.
1892 const ASTRecordLayout &Layout = getContext().getASTRecordLayout(RD);
1893 if (Layout.getBaseClassOffset(BaseRD) +
1894 getContext().getASTRecordLayout(BaseRD).getSize() <=
1895 Layout.getNonVirtualSize())
1896 return AggValueSlot::DoesNotOverlap;
1898 // The tail padding may contain values we need to preserve.
1899 return AggValueSlot::MayOverlap;
1902 void CodeGenFunction::EmitAggregateCopy(LValue Dest, LValue Src, QualType Ty,
1903 AggValueSlot::Overlap_t MayOverlap,
1905 assert(!Ty->isAnyComplexType() && "Shouldn't happen for complex");
1907 Address DestPtr = Dest.getAddress(*this);
1908 Address SrcPtr = Src.getAddress(*this);
1910 if (getLangOpts().CPlusPlus) {
1911 if (const RecordType *RT = Ty->getAs<RecordType>()) {
1912 CXXRecordDecl *Record = cast<CXXRecordDecl>(RT->getDecl());
1913 assert((Record->hasTrivialCopyConstructor() ||
1914 Record->hasTrivialCopyAssignment() ||
1915 Record->hasTrivialMoveConstructor() ||
1916 Record->hasTrivialMoveAssignment() ||
1917 Record->hasAttr<TrivialABIAttr>() || Record->isUnion()) &&
1918 "Trying to aggregate-copy a type without a trivial copy/move "
1919 "constructor or assignment operator");
1920 // Ignore empty classes in C++.
1921 if (Record->isEmpty())
1926 // Aggregate assignment turns into llvm.memcpy. This is almost valid per
1927 // C99 6.5.16.1p3, which states "If the value being stored in an object is
1928 // read from another object that overlaps in anyway the storage of the first
1929 // object, then the overlap shall be exact and the two objects shall have
1930 // qualified or unqualified versions of a compatible type."
1932 // memcpy is not defined if the source and destination pointers are exactly
1933 // equal, but other compilers do this optimization, and almost every memcpy
1934 // implementation handles this case safely. If there is a libc that does not
1935 // safely handle this, we can add a target hook.
1937 // Get data size info for this aggregate. Don't copy the tail padding if this
1938 // might be a potentially-overlapping subobject, since the tail padding might
1939 // be occupied by a different object. Otherwise, copying it is fine.
1940 std::pair<CharUnits, CharUnits> TypeInfo;
1942 TypeInfo = getContext().getTypeInfoDataSizeInChars(Ty);
1944 TypeInfo = getContext().getTypeInfoInChars(Ty);
1946 llvm::Value *SizeVal = nullptr;
1947 if (TypeInfo.first.isZero()) {
1948 // But note that getTypeInfo returns 0 for a VLA.
1949 if (auto *VAT = dyn_cast_or_null<VariableArrayType>(
1950 getContext().getAsArrayType(Ty))) {
1952 SizeVal = emitArrayLength(VAT, BaseEltTy, DestPtr);
1953 TypeInfo = getContext().getTypeInfoInChars(BaseEltTy);
1954 assert(!TypeInfo.first.isZero());
1955 SizeVal = Builder.CreateNUWMul(
1957 llvm::ConstantInt::get(SizeTy, TypeInfo.first.getQuantity()));
1961 SizeVal = llvm::ConstantInt::get(SizeTy, TypeInfo.first.getQuantity());
1964 // FIXME: If we have a volatile struct, the optimizer can remove what might
1965 // appear to be `extra' memory ops:
1967 // volatile struct { int i; } a, b;
1974 // we need to use a different call here. We use isVolatile to indicate when
1975 // either the source or the destination is volatile.
1977 DestPtr = Builder.CreateElementBitCast(DestPtr, Int8Ty);
1978 SrcPtr = Builder.CreateElementBitCast(SrcPtr, Int8Ty);
1980 // Don't do any of the memmove_collectable tests if GC isn't set.
1981 if (CGM.getLangOpts().getGC() == LangOptions::NonGC) {
1983 } else if (const RecordType *RecordTy = Ty->getAs<RecordType>()) {
1984 RecordDecl *Record = RecordTy->getDecl();
1985 if (Record->hasObjectMember()) {
1986 CGM.getObjCRuntime().EmitGCMemmoveCollectable(*this, DestPtr, SrcPtr,
1990 } else if (Ty->isArrayType()) {
1991 QualType BaseType = getContext().getBaseElementType(Ty);
1992 if (const RecordType *RecordTy = BaseType->getAs<RecordType>()) {
1993 if (RecordTy->getDecl()->hasObjectMember()) {
1994 CGM.getObjCRuntime().EmitGCMemmoveCollectable(*this, DestPtr, SrcPtr,
2001 auto Inst = Builder.CreateMemCpy(DestPtr, SrcPtr, SizeVal, isVolatile);
2003 // Determine the metadata to describe the position of any padding in this
2004 // memcpy, as well as the TBAA tags for the members of the struct, in case
2005 // the optimizer wishes to expand it in to scalar memory operations.
2006 if (llvm::MDNode *TBAAStructTag = CGM.getTBAAStructInfo(Ty))
2007 Inst->setMetadata(llvm::LLVMContext::MD_tbaa_struct, TBAAStructTag);
2009 if (CGM.getCodeGenOpts().NewStructPathTBAA) {
2010 TBAAAccessInfo TBAAInfo = CGM.mergeTBAAInfoForMemoryTransfer(
2011 Dest.getTBAAInfo(), Src.getTBAAInfo());
2012 CGM.DecorateInstructionWithTBAA(Inst, TBAAInfo);