1//===--- CGExprAgg.cpp - Emit LLVM Code from Aggregate Expressions --------===//
2//
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
6//
7//===----------------------------------------------------------------------===//
8//
9// This contains code to emit Aggregate Expr nodes as LLVM code.
10//
11//===----------------------------------------------------------------------===//
12
13#include "CGCXXABI.h"
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"
29using namespace clang;
30using namespace CodeGen;
31
32//===----------------------------------------------------------------------===//
33// Aggregate Expression Emitter
34//===----------------------------------------------------------------------===//
35
36namespace {
37class AggExprEmitter : public StmtVisitor<AggExprEmitter> {
38 CodeGenFunction &CGF;
39 CGBuilderTy &Builder;
40 AggValueSlot Dest;
41 bool IsResultUnused;
42
43 AggValueSlot EnsureSlot(QualType T) {
44 if (!Dest.isIgnored()) return Dest;
45 return CGF.CreateAggTemp(T, "agg.tmp.ensured");
46 }
47 void EnsureDest(QualType T) {
48 if (!Dest.isIgnored()) return;
49 Dest = CGF.CreateAggTemp(T, "agg.tmp.ensured");
50 }
51
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.
55 //
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);
60
61public:
62 AggExprEmitter(CodeGenFunction &cgf, AggValueSlot Dest, bool IsResultUnused)
63 : CGF(cgf), Builder(CGF.Builder), Dest(Dest),
64 IsResultUnused(IsResultUnused) { }
65
66 //===--------------------------------------------------------------------===//
67 // Utilities
68 //===--------------------------------------------------------------------===//
69
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);
74
75 enum ExprValueKind {
76 EVK_RValue,
77 EVK_NonRValue
78 };
79
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);
87
88 void EmitMoveFromReturnSlot(const Expr *E, RValue Src);
89
90 void EmitArrayInit(Address DestPtr, llvm::ArrayType *AType,
91 QualType ArrayQTy, InitListExpr *E);
92
93 AggValueSlot::NeedsGCBarriers_t needsGC(QualType T) {
94 if (CGF.getLangOpts().getGC() && TypeRequiresGCollection(T))
95 return AggValueSlot::NeedsGCBarriers;
96 return AggValueSlot::DoesNotNeedGCBarriers;
97 }
98
99 bool TypeRequiresGCollection(QualType T);
100
101 //===--------------------------------------------------------------------===//
102 // Visitor Methods
103 //===--------------------------------------------------------------------===//
104
105 void Visit(Expr *E) {
106 ApplyDebugLocation DL(CGF, E);
107 StmtVisitor<AggExprEmitter>::Visit(E);
108 }
109
110 void VisitStmt(Stmt *S) {
111 CGF.ErrorUnsupported(S, "aggregate expression");
112 }
113 void VisitParenExpr(ParenExpr *PE) { Visit(PE->getSubExpr()); }
114 void VisitGenericSelectionExpr(GenericSelectionExpr *GE) {
115 Visit(GE->getResultExpr());
116 }
117 void VisitCoawaitExpr(CoawaitExpr *E) {
118 CGF.EmitCoawaitExpr(*E, Dest, IsResultUnused);
119 }
120 void VisitCoyieldExpr(CoyieldExpr *E) {
121 CGF.EmitCoyieldExpr(*E, Dest, IsResultUnused);
122 }
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());
127 }
128
129 void VisitConstantExpr(ConstantExpr *E) {
130 if (llvm::Value *Result = ConstantEmitter(CGF).tryEmitConstantExpr(E)) {
131 CGF.EmitAggregateStore(Result, Dest.getAddress(),
132 E->getType().isVolatileQualified());
133 return;
134 }
135 return Visit(E->getSubExpr());
136 }
137
138 // l-values.
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);
146 }
147 void VisitPredefinedExpr(const PredefinedExpr *E) {
148 EmitAggLoadOfLValue(E);
149 }
150
151 // Operators.
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());
162 }
163
164 void VisitObjCMessageExpr(ObjCMessageExpr *E);
165 void VisitObjCIvarRefExpr(ObjCIvarRefExpr *E) {
166 EmitAggLoadOfLValue(E);
167 }
168
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());
180 }
181 void VisitCXXDefaultInitExpr(CXXDefaultInitExpr *DIE) {
182 CodeGenFunction::CXXDefaultInitExprScope Scope(CGF, DIE);
183 Visit(DIE->getExpr());
184 }
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);
195
196 void VisitPseudoObjectExpr(PseudoObjectExpr *E) {
197 if (E->isGLValue()) {
198 LValue LV = CGF.EmitPseudoObjectLValue(E);
199 return EmitFinalDestCopy(E->getType(), LV);
200 }
201
202 CGF.EmitPseudoObjectRValue(E, EnsureSlot(E->getType()));
203 }
204
205 void VisitVAArgExpr(VAArgExpr *E);
206
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);
214 }
215};
216} // end anonymous namespace.
217
218//===----------------------------------------------------------------------===//
219// Utilities
220//===----------------------------------------------------------------------===//
221
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.
225void AggExprEmitter::EmitAggLoadOfLValue(const Expr *E) {
226 LValue LV = CGF.EmitLValue(E);
227
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);
231 return;
232 }
233
234 EmitFinalDestCopy(E->getType(), LV);
235}
236
237/// True if the given aggregate type requires special GC API calls.
238bool 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;
242
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()))
248 return false;
249
250 // Check whether the type has an object member.
251 return Record->hasObjectMember();
252}
253
254void 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;
260
261 // If it makes no observable difference, save a memcpy + temporary.
262 //
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());
268
269 Address RetAddr = Address::invalid();
270 Address RetAllocaAddr = Address::invalid();
271
272 EHScopeStack::stable_iterator LifetimeEndBlock;
273 llvm::Value *LifetimeSizePtr = nullptr;
274 llvm::IntrinsicInst *LifetimeStartInst = nullptr;
275 if (!UseTemp) {
276 RetAddr = Dest.getAddress();
277 } else {
278 RetAddr = CGF.CreateMemTemp(RetTy, "tmp", &RetAllocaAddr);
279 uint64_t Size =
280 CGF.CGM.getDataLayout().getTypeAllocSize(CGF.ConvertTypeForMem(RetTy));
281 LifetimeSizePtr = CGF.EmitLifetimeStart(Size, RetAllocaAddr.getPointer());
282 if (LifetimeSizePtr) {
283 LifetimeStartInst =
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?");
288
289 CGF.pushFullExprCleanup<CodeGenFunction::CallLifetimeEnd>(
290 NormalEHLifetimeMarker, RetAllocaAddr, LifetimeSizePtr);
291 LifetimeEndBlock = CGF.EHStack.stable_begin();
292 }
293 }
294
295 RValue Src =
296 EmitCall(ReturnValueSlot(RetAddr, Dest.isVolatile(), IsResultUnused,
297 Dest.isExternallyDestructed()));
298
299 if (!UseTemp)
300 return;
301
302 assert(Dest.getPointer() != Src.getAggregatePointer());
303 EmitFinalDestCopy(E->getType(), Src);
304
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
308 // eagerly.
309 CGF.DeactivateCleanupBlock(LifetimeEndBlock, LifetimeStartInst);
310 CGF.EmitLifetimeEnd(LifetimeSizePtr, RetAllocaAddr.getPointer());
311 }
312}
313
314/// EmitFinalDestCopy - Perform the final copy to DestPtr, if desired.
315void 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);
319}
320
321/// EmitFinalDestCopy - Perform the final copy to DestPtr, if desired.
322void 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
327 // destination.
328 if (Dest.isIgnored())
329 return;
330
331 // Copy non-trivial C structs here.
332 LValue DstLV = CGF.MakeAddrLValue(
333 Dest.getAddress(), Dest.isVolatile() ? type.withVolatile() : type);
334
335 if (SrcValueKind == EVK_RValue) {
336 if (type.isNonTrivialToPrimitiveDestructiveMove() == QualType::PCK_Struct) {
337 if (Dest.isPotentiallyAliased())
338 CGF.callCStructMoveAssignmentOperator(DstLV, src);
339 else
340 CGF.callCStructMoveConstructor(DstLV, src);
341 return;
342 }
343 } else {
344 if (type.isNonTrivialToPrimitiveCopy() == QualType::PCK_Struct) {
345 if (Dest.isPotentiallyAliased())
346 CGF.callCStructCopyAssignmentOperator(DstLV, src);
347 else
348 CGF.callCStructCopyConstructor(DstLV, src);
349 return;
350 }
351 }
352
353 AggValueSlot srcAgg = AggValueSlot::forLValue(
354 src, CGF, AggValueSlot::IsDestructed, needsGC(type),
355 AggValueSlot::IsAliased, AggValueSlot::MayOverlap);
356 EmitCopy(type, Dest, srcAgg);
357}
358
359/// Perform a copy from the source into the destination.
360///
361/// \param type - the type of the aggregate being copied; qualifiers are
362/// ignored
363void 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,
369 dest.getAddress(),
370 src.getAddress(),
371 size);
372 return;
373 }
374
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
377 // the two sides.
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());
382}
383
384/// Emit the initializer for a std::initializer_list initialized with a
385/// real initializer list.
386void
387AggExprEmitter::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);
394
395 const ConstantArrayType *ArrayType =
396 Ctx.getAsConstantArrayType(E->getSubExpr()->getType());
397 assert(ArrayType && "std::initializer_list constructed from non-array");
398
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");
404 return;
405 }
406
407 // Start pointer.
408 if (!Field->getType()->isPointerType() ||
409 !Ctx.hasSameType(Field->getType()->getPointeeType(),
410 ArrayType->getElementType())) {
411 CGF.ErrorUnsupported(E, "weird std::initializer_list");
412 return;
413 }
414
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);
423 ++Field;
424
425 if (Field == Record->field_end()) {
426 CGF.ErrorUnsupported(E, "weird std::initializer_list");
427 return;
428 }
429
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())) {
435 // End pointer.
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())) {
441 // Length.
442 CGF.EmitStoreThroughLValue(RValue::get(Size), EndOrLength);
443 } else {
444 CGF.ErrorUnsupported(E, "weird std::initializer_list");
445 return;
446 }
447}
448
449/// Determine if E is a trivial array filler, that is, one that is
450/// equivalent to zero-initialization.
451static bool isTrivialFiller(Expr *E) {
452 if (!E)
453 return true;
454
455 if (isa<ImplicitValueInitExpr>(E))
456 return true;
457
458 if (auto *ILE = dyn_cast<InitListExpr>(E)) {
459 if (ILE->getNumInits())
460 return false;
461 return isTrivialFiller(ILE->getArrayFiller());
462 }
463
464 if (auto *Cons = dyn_cast_or_null<CXXConstructExpr>(E))
465 return Cons->getConstructor()->isDefaultConstructor() &&
466 Cons->getConstructor()->isTrivial();
467
468 // FIXME: Are there other cases where we can avoid emitting an initializer?
469 return false;
470}
471
472/// Emit initialization of an array from an initializer list.
473void AggExprEmitter::EmitArrayInit(Address DestPtr, llvm::ArrayType *AType,
474 QualType ArrayQTy, InitListExpr *E) {
475 uint64_t NumInitElements = E->getNumInits();
476
477 uint64_t NumArrayElements = AType->getNumElements();
478 assert(NumInitElements <= NumArrayElements);
479
480 QualType elementType =
481 CGF.getContext().getAsArrayType(ArrayQTy)->getElementType();
482
483 // DestPtr is an array*. Construct an elementType* by drilling
484 // down a level.
485 llvm::Value *zero = llvm::ConstantInt::get(CGF.SizeTy, 0);
486 llvm::Value *indices[] = { zero, zero };
487 llvm::Value *begin =
488 Builder.CreateInBoundsGEP(DestPtr.getPointer(), indices, "arrayinit.begin");
489
490 CharUnits elementSize = CGF.getContext().getTypeSizeInChars(elementType);
491 CharUnits elementAlign =
492 DestPtr.getAlignment().alignmentOfArrayElement(elementSize);
493
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));
513 return;
514 }
515 }
516
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
528 // alloca.
529 endOfInit = CGF.CreateTempAlloca(begin->getType(), CGF.getPointerAlign(),
530 "arrayinit.endOfInit");
531 cleanupDominator = Builder.CreateStore(begin, endOfInit);
532 CGF.pushIrregularPartialArrayCleanup(begin, endOfInit, elementType,
533 elementAlign,
534 CGF.getDestroyer(dtorKind));
535 cleanup = CGF.EHStack.stable_begin();
536
537 // Otherwise, remember that we didn't need a cleanup.
538 } else {
539 dtorKind = QualType::DK_none;
540 }
541
542 llvm::Value *one = llvm::ConstantInt::get(CGF.SizeTy, 1);
543
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;
550
551 // Emit the explicit initializers.
552 for (uint64_t i = 0; i != NumInitElements; ++i) {
553 // Advance to the next element.
554 if (i > 0) {
555 element = Builder.CreateInBoundsGEP(element, one, "arrayinit.element");
556
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);
561 }
562
563 LValue elementLV =
564 CGF.MakeAddrLValue(Address(element, elementAlign), elementType);
565 EmitInitializationToLValue(E->getInit(i), elementLV);
566 }
567
568 // Check whether there's a non-trivial array-fill expression.
569 Expr *filler = E->getArrayFiller();
570 bool hasTrivialFiller = isTrivialFiller(filler);
571
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))) {
578
579 // Use an actual loop. This is basically
580 // do { *array++ = filler; } while (array != end);
581
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);
586 }
587
588 // Compute the end of the array.
589 llvm::Value *end = Builder.CreateInBoundsGEP(begin,
590 llvm::ConstantInt::get(CGF.SizeTy, NumArrayElements),
591 "arrayinit.end");
592
593 llvm::BasicBlock *entryBB = Builder.GetInsertBlock();
594 llvm::BasicBlock *bodyBB = CGF.createBasicBlock("arrayinit.body");
595
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);
601
602 // Emit the actual filler expression.
603 {
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);
610 LValue elementLV =
611 CGF.MakeAddrLValue(Address(currentElement, elementAlign), elementType);
612 if (filler)
613 EmitInitializationToLValue(filler, elementLV);
614 else
615 EmitNullInitializationToLValue(elementLV);
616 }
617
618 // Move on to the next element.
619 llvm::Value *nextElement =
620 Builder.CreateInBoundsGEP(currentElement, one, "arrayinit.next");
621
622 // Tell the EH cleanup that we finished with the last element.
623 if (endOfInit.isValid()) Builder.CreateStore(nextElement, endOfInit);
624
625 // Leave the loop if we're done.
626 llvm::Value *done = Builder.CreateICmpEQ(nextElement, end,
627 "arrayinit.done");
628 llvm::BasicBlock *endBB = CGF.createBasicBlock("arrayinit.end");
629 Builder.CreateCondBr(done, endBB, bodyBB);
630 currentElement->addIncoming(nextElement, Builder.GetInsertBlock());
631
632 CGF.EmitBlock(endBB);
633 }
634
635 // Leave the partial-array cleanup if we entered one.
636 if (dtorKind) CGF.DeactivateCleanupBlock(cleanup, cleanupDominator);
637}
638
639//===----------------------------------------------------------------------===//
640// Visitor Methods
641//===----------------------------------------------------------------------===//
642
643void AggExprEmitter::VisitMaterializeTemporaryExpr(MaterializeTemporaryExpr *E){
644 Visit(E->getSubExpr());
645}
646
647void AggExprEmitter::VisitOpaqueValueExpr(OpaqueValueExpr *e) {
648 // If this is a unique OVE, just visit its source expression.
649 if (e->isUnique())
650 Visit(e->getSourceExpr());
651 else
652 EmitFinalDestCopy(e->getType(), CGF.getOrCreateOpaqueLValueMapping(e));
653}
654
655void
656AggExprEmitter::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);
662 return;
663 }
664
665 AggValueSlot Slot = EnsureSlot(E->getType());
666
667 // Block-scope compound literals are destroyed at the end of the enclosing
668 // scope in C.
669 bool Destruct =
670 !CGF.getLangOpts().CPlusPlus && !Slot.isExternallyDestructed();
671 if (Destruct)
672 Slot.setExternallyDestructed();
673
674 CGF.EmitAggExpr(E->getInitializer(), Slot);
675
676 if (Destruct)
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);
681}
682
683/// Attempt to look through various unimportant expressions to find a
684/// cast of the given kind.
685static 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();
690 }
691 return nullptr;
692}
693
694void AggExprEmitter::VisitCastExpr(CastExpr *E) {
695 if (const auto *ECE = dyn_cast<ExplicitCastExpr>(E))
696 CGF.CGM.EmitExplicitCastExprType(ECE, &CGF);
697 switch (E->getCastKind()) {
698 case CK_Dynamic: {
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?
704 if (LV.isSimple())
705 CGF.EmitDynamicCast(LV.getAddress(CGF), cast<CXXDynamicCastExpr>(E));
706 else
707 CGF.CGM.ErrorUnsupported(E, "non-simple lvalue dynamic_cast");
708
709 if (!Dest.isIgnored())
710 CGF.CGM.ErrorUnsupported(E, "lvalue dynamic_cast with a destination");
711 break;
712 }
713
714 case CK_ToUnion: {
715 // Evaluate even if the destination is ignored.
716 if (Dest.isIgnored()) {
717 CGF.EmitAnyExpr(E->getSubExpr(), AggValueSlot::ignored(),
718 /*ignoreResult=*/true);
719 break;
720 }
721
722 // GCC union extension
723 QualType Ty = E->getSubExpr()->getType();
724 Address CastPtr =
725 Builder.CreateElementBitCast(Dest.getAddress(), CGF.ConvertType(Ty));
726 EmitInitializationToLValue(E->getSubExpr(),
727 CGF.MakeAddrLValue(CastPtr, Ty));
728 break;
729 }
730
731 case CK_LValueToRValueBitCast: {
732 if (Dest.isIgnored()) {
733 CGF.EmitAnyExpr(E->getSubExpr(), AggValueSlot::ignored(),
734 /*ignoreResult=*/true);
735 break;
736 }
737
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(
744 CGF.SizeTy,
745 CGF.getContext().getTypeSizeInChars(E->getType()).getQuantity());
746 Builder.CreateMemCpy(DestAddress, SourceAddress, SizeVal);
747 break;
748 }
749
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");
755 }
756
757 case CK_NonAtomicToAtomic:
758 case CK_AtomicToNonAtomic: {
759 bool isToAtomic = (E->getCastKind() == CK_NonAtomicToAtomic);
760
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);
765
766 assert(atomicType->isAtomicType());
767 assert(CGF.getContext().hasSameUnqualifiedType(valueType,
768 atomicType->castAs<AtomicType>()->getValueType()));
769
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());
774 }
775
776 CastKind peepholeTarget =
777 (isToAtomic ? CK_AtomicToNonAtomic : CK_NonAtomicToAtomic);
778
779 // These two cases are reverses of each other; try to peephole them.
780 if (Expr *op =
781 findPeephole(E->getSubExpr(), peepholeTarget, CGF.getContext())) {
782 assert(CGF.getContext().hasSameUnqualifiedType(op->getType(),
783 E->getType()) &&
784 "peephole significantly changed types?");
785 return Visit(op);
786 }
787
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.
790 if (isToAtomic) {
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);
797
798 // Build a GEP to refer to the subobject.
799 Address valueAddr =
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);
808 }
809
810 CGF.EmitAggExpr(E->getSubExpr(), valueDest);
811 return;
812 }
813
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);
819
820 Address valueAddr = Builder.CreateStructGEP(atomicSlot.getAddress(), 0);
821 RValue rvalue = RValue::getAggregate(valueAddr, atomicSlot.isVolatile());
822 return EmitFinalDestCopy(valueType, rvalue);
823 }
824 case CK_AddressSpaceConversion:
825 return Visit(E->getSubExpr());
826
827 case CK_LValueToRValue:
828 // If we're loading from a volatile type, force the destination
829 // into existence.
830 if (E->getSubExpr()->getType().isVolatileQualified()) {
831 bool Destruct =
832 !Dest.isExternallyDestructed() &&
833 E->getType().isDestructedType() == QualType::DK_nontrivial_c_struct;
834 if (Destruct)
835 Dest.setExternallyDestructed();
836 EnsureDest(E->getType());
837 Visit(E->getSubExpr());
838
839 if (Destruct)
840 CGF.pushDestroy(QualType::DK_nontrivial_c_struct, Dest.getAddress(),
841 E->getType());
842
843 return;
844 }
845
846 LLVM_FALLTHROUGH;
847
848
849 case CK_NoOp:
850 case CK_UserDefinedConversion:
851 case CK_ConstructorConversion:
852 assert(CGF.getContext().hasSameUnqualifiedType(E->getSubExpr()->getType(),
853 E->getType()) &&
854 "Implicit cast types must be compatible");
855 Visit(E->getSubExpr());
856 break;
857
858 case CK_LValueBitCast:
859 llvm_unreachable("should not be emitting lvalue bitcast as rvalue");
860
861 case CK_Dependent:
862 case CK_BitCast:
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:
874 case CK_ToVoid:
875 case CK_VectorSplat:
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:
904 case CK_MatrixCast:
905
906 case CK_IntToOCLSampler:
907 case CK_FloatingToFixedPoint:
908 case CK_FixedPointToFloating:
909 case CK_FixedPointCast:
910 case CK_FixedPointToBoolean:
911 case CK_FixedPointToIntegral:
912 case CK_IntegralToFixedPoint:
913 llvm_unreachable("cast kind invalid for aggregate types");
914 }
915}
916
917void AggExprEmitter::VisitCallExpr(const CallExpr *E) {
918 if (E->getCallReturnType(CGF.getContext())->isReferenceType()) {
919 EmitAggLoadOfLValue(E);
920 return;
921 }
922
923 withReturnValueSlot(E, [&](ReturnValueSlot Slot) {
924 return CGF.EmitCallExpr(E, Slot);
925 });
926}
927
928void AggExprEmitter::VisitObjCMessageExpr(ObjCMessageExpr *E) {
929 withReturnValueSlot(E, [&](ReturnValueSlot Slot) {
930 return CGF.EmitObjCMessageExpr(E, Slot);
931 });
932}
933
934void AggExprEmitter::VisitBinComma(const BinaryOperator *E) {
935 CGF.EmitIgnoredExpr(E->getLHS());
936 Visit(E->getRHS());
937}
938
939void AggExprEmitter::VisitStmtExpr(const StmtExpr *E) {
940 CodeGenFunction::StmtExprEvaluation eval(CGF);
941 CGF.EmitCompoundStmt(*E->getSubStmt(), true, Dest);
942}
943
944enum CompareKind {
945 CK_Less,
946 CK_Greater,
947 CK_Equal,
948};
949
950static llvm::Value *EmitCompare(CGBuilderTy &Builder, CodeGenFunction &CGF,
951 const BinaryOperator *E, llvm::Value *LHS,
952 llvm::Value *RHS, CompareKind Kind,
953 const char *NameSuffix = "") {
954 QualType ArgTy = E->getLHS()->getType();
955 if (const ComplexType *CT = ArgTy->getAs<ComplexType>())
956 ArgTy = CT->getElementType();
957
958 if (const auto *MPT = ArgTy->getAs<MemberPointerType>()) {
959 assert(Kind == CK_Equal &&
960 "member pointers may only be compared for equality");
961 return CGF.CGM.getCXXABI().EmitMemberPointerComparison(
962 CGF, LHS, RHS, MPT, /*IsInequality*/ false);
963 }
964
965 // Compute the comparison instructions for the specified comparison kind.
966 struct CmpInstInfo {
967 const char *Name;
968 llvm::CmpInst::Predicate FCmp;
969 llvm::CmpInst::Predicate SCmp;
970 llvm::CmpInst::Predicate UCmp;
971 };
972 CmpInstInfo InstInfo = [&]() -> CmpInstInfo {
973 using FI = llvm::FCmpInst;
974 using II = llvm::ICmpInst;
975 switch (Kind) {
976 case CK_Less:
977 return {"cmp.lt", FI::FCMP_OLT, II::ICMP_SLT, II::ICMP_ULT};
978 case CK_Greater:
979 return {"cmp.gt", FI::FCMP_OGT, II::ICMP_SGT, II::ICMP_UGT};
980 case CK_Equal:
981 return {"cmp.eq", FI::FCMP_OEQ, II::ICMP_EQ, II::ICMP_EQ};
982 }
983 llvm_unreachable("Unrecognised CompareKind enum");
984 }();
985
986 if (ArgTy->hasFloatingRepresentation())
987 return Builder.CreateFCmp(InstInfo.FCmp, LHS, RHS,
988 llvm::Twine(InstInfo.Name) + NameSuffix);
989 if (ArgTy->isIntegralOrEnumerationType() || ArgTy->isPointerType()) {
990 auto Inst =
991 ArgTy->hasSignedIntegerRepresentation() ? InstInfo.SCmp : InstInfo.UCmp;
992 return Builder.CreateICmp(Inst, LHS, RHS,
993 llvm::Twine(InstInfo.Name) + NameSuffix);
994 }
995
996 llvm_unreachable("unsupported aggregate binary expression should have "
997 "already been handled");
998}
999
1000void AggExprEmitter::VisitBinCmp(const BinaryOperator *E) {
1001 using llvm::BasicBlock;
1002 using llvm::PHINode;
1003 using llvm::Value;
1004 assert(CGF.getContext().hasSameType(E->getLHS()->getType(),
1005 E->getRHS()->getType()));
1006 const ComparisonCategoryInfo &CmpInfo =
1007 CGF.getContext().CompCategories.getInfoForType(E->getType());
1008 assert(CmpInfo.Record->isTriviallyCopyable() &&
1009 "cannot copy non-trivially copyable aggregate");
1010
1011 QualType ArgTy = E->getLHS()->getType();
1012
1013 if (!ArgTy->isIntegralOrEnumerationType() && !ArgTy->isRealFloatingType() &&
1014 !ArgTy->isNullPtrType() && !ArgTy->isPointerType() &&
1015 !ArgTy->isMemberPointerType() && !ArgTy->isAnyComplexType()) {
1016 return CGF.ErrorUnsupported(E, "aggregate three-way comparison");
1017 }
1018 bool IsComplex = ArgTy->isAnyComplexType();
1019
1020 // Evaluate the operands to the expression and extract their values.
1021 auto EmitOperand = [&](Expr *E) -> std::pair<Value *, Value *> {
1022 RValue RV = CGF.EmitAnyExpr(E);
1023 if (RV.isScalar())
1024 return {RV.getScalarVal(), nullptr};
1025 if (RV.isAggregate())
1026 return {RV.getAggregatePointer(), nullptr};
1027 assert(RV.isComplex());
1028 return RV.getComplexVal();
1029 };
1030 auto LHSValues = EmitOperand(E->getLHS()),
1031 RHSValues = EmitOperand(E->getRHS());
1032
1033 auto EmitCmp = [&](CompareKind K) {
1034 Value *Cmp = EmitCompare(Builder, CGF, E, LHSValues.first, RHSValues.first,
1035 K, IsComplex ? ".r" : "");
1036 if (!IsComplex)
1037 return Cmp;
1038 assert(K == CompareKind::CK_Equal);
1039 Value *CmpImag = EmitCompare(Builder, CGF, E, LHSValues.second,
1040 RHSValues.second, K, ".i");
1041 return Builder.CreateAnd(Cmp, CmpImag, "and.eq");
1042 };
1043 auto EmitCmpRes = [&](const ComparisonCategoryInfo::ValueInfo *VInfo) {
1044 return Builder.getInt(VInfo->getIntValue());
1045 };
1046
1047 Value *Select;
1048 if (ArgTy->isNullPtrType()) {
1049 Select = EmitCmpRes(CmpInfo.getEqualOrEquiv());
1050 } else if (!CmpInfo.isPartial()) {
1051 Value *SelectOne =
1052 Builder.CreateSelect(EmitCmp(CK_Less), EmitCmpRes(CmpInfo.getLess()),
1053 EmitCmpRes(CmpInfo.getGreater()), "sel.lt");
1054 Select = Builder.CreateSelect(EmitCmp(CK_Equal),
1055 EmitCmpRes(CmpInfo.getEqualOrEquiv()),
1056 SelectOne, "sel.eq");
1057 } else {
1058 Value *SelectEq = Builder.CreateSelect(
1059 EmitCmp(CK_Equal), EmitCmpRes(CmpInfo.getEqualOrEquiv()),
1060 EmitCmpRes(CmpInfo.getUnordered()), "sel.eq");
1061 Value *SelectGT = Builder.CreateSelect(EmitCmp(CK_Greater),
1062 EmitCmpRes(CmpInfo.getGreater()),
1063 SelectEq, "sel.gt");
1064 Select = Builder.CreateSelect(
1065 EmitCmp(CK_Less), EmitCmpRes(CmpInfo.getLess()), SelectGT, "sel.lt");
1066 }
1067 // Create the return value in the destination slot.
1068 EnsureDest(E->getType());
1069 LValue DestLV = CGF.MakeAddrLValue(Dest.getAddress(), E->getType());
1070
1071 // Emit the address of the first (and only) field in the comparison category
1072 // type, and initialize it from the constant integer value selected above.
1073 LValue FieldLV = CGF.EmitLValueForFieldInitialization(
1074 DestLV, *CmpInfo.Record->field_begin());
1075 CGF.EmitStoreThroughLValue(RValue::get(Select), FieldLV, /*IsInit*/ true);
1076
1077 // All done! The result is in the Dest slot.
1078}
1079
1080void AggExprEmitter::VisitBinaryOperator(const BinaryOperator *E) {
1081 if (E->getOpcode() == BO_PtrMemD || E->getOpcode() == BO_PtrMemI)
1082 VisitPointerToDataMemberBinaryOperator(E);
1083 else
1084 CGF.ErrorUnsupported(E, "aggregate binary expression");
1085}
1086
1087void AggExprEmitter::VisitPointerToDataMemberBinaryOperator(
1088 const BinaryOperator *E) {
1089 LValue LV = CGF.EmitPointerToDataMemberBinaryExpr(E);
1090 EmitFinalDestCopy(E->getType(), LV);
1091}
1092
1093/// Is the value of the given expression possibly a reference to or
1094/// into a __block variable?
1095static bool isBlockVarRef(const Expr *E) {
1096 // Make sure we look through parens.
1097 E = E->IgnoreParens();
1098
1099 // Check for a direct reference to a __block variable.
1100 if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E)) {
1101 const VarDecl *var = dyn_cast<VarDecl>(DRE->getDecl());
1102 return (var && var->hasAttr<BlocksAttr>());
1103 }
1104
1105 // More complicated stuff.
1106
1107 // Binary operators.
1108 if (const BinaryOperator *op = dyn_cast<BinaryOperator>(E)) {
1109 // For an assignment or pointer-to-member operation, just care
1110 // about the LHS.
1111 if (op->isAssignmentOp() || op->isPtrMemOp())
1112 return isBlockVarRef(op->getLHS());
1113
1114 // For a comma, just care about the RHS.
1115 if (op->getOpcode() == BO_Comma)
1116 return isBlockVarRef(op->getRHS());
1117
1118 // FIXME: pointer arithmetic?
1119 return false;
1120
1121 // Check both sides of a conditional operator.
1122 } else if (const AbstractConditionalOperator *op
1123 = dyn_cast<AbstractConditionalOperator>(E)) {
1124 return isBlockVarRef(op->getTrueExpr())
1125 || isBlockVarRef(op->getFalseExpr());
1126
1127 // OVEs are required to support BinaryConditionalOperators.
1128 } else if (const OpaqueValueExpr *op
1129 = dyn_cast<OpaqueValueExpr>(E)) {
1130 if (const Expr *src = op->getSourceExpr())
1131 return isBlockVarRef(src);
1132
1133 // Casts are necessary to get things like (*(int*)&var) = foo().
1134 // We don't really care about the kind of cast here, except
1135 // we don't want to look through l2r casts, because it's okay
1136 // to get the *value* in a __block variable.
1137 } else if (const CastExpr *cast = dyn_cast<CastExpr>(E)) {
1138 if (cast->getCastKind() == CK_LValueToRValue)
1139 return false;
1140 return isBlockVarRef(cast->getSubExpr());
1141
1142 // Handle unary operators. Again, just aggressively look through
1143 // it, ignoring the operation.
1144 } else if (const UnaryOperator *uop = dyn_cast<UnaryOperator>(E)) {
1145 return isBlockVarRef(uop->getSubExpr());
1146
1147 // Look into the base of a field access.
1148 } else if (const MemberExpr *mem = dyn_cast<MemberExpr>(E)) {
1149 return isBlockVarRef(mem->getBase());
1150
1151 // Look into the base of a subscript.
1152 } else if (const ArraySubscriptExpr *sub = dyn_cast<ArraySubscriptExpr>(E)) {
1153 return isBlockVarRef(sub->getBase());
1154 }
1155
1156 return false;
1157}
1158
1159void AggExprEmitter::VisitBinAssign(const BinaryOperator *E) {
1160 // For an assignment to work, the value on the right has
1161 // to be compatible with the value on the left.
1162 assert(CGF.getContext().hasSameUnqualifiedType(E->getLHS()->getType(),
1163 E->getRHS()->getType())
1164 && "Invalid assignment");
1165
1166 // If the LHS might be a __block variable, and the RHS can
1167 // potentially cause a block copy, we need to evaluate the RHS first
1168 // so that the assignment goes the right place.
1169 // This is pretty semantically fragile.
1170 if (isBlockVarRef(E->getLHS()) &&
1171 E->getRHS()->HasSideEffects(CGF.getContext())) {
1172 // Ensure that we have a destination, and evaluate the RHS into that.
1173 EnsureDest(E->getRHS()->getType());
1174 Visit(E->getRHS());
1175
1176 // Now emit the LHS and copy into it.
1177 LValue LHS = CGF.EmitCheckedLValue(E->getLHS(), CodeGenFunction::TCK_Store);
1178
1179 // That copy is an atomic copy if the LHS is atomic.
1180 if (LHS.getType()->isAtomicType() ||
1181 CGF.LValueIsSuitableForInlineAtomic(LHS)) {
1182 CGF.EmitAtomicStore(Dest.asRValue(), LHS, /*isInit*/ false);
1183 return;
1184 }
1185
1186 EmitCopy(E->getLHS()->getType(),
1187 AggValueSlot::forLValue(LHS, CGF, AggValueSlot::IsDestructed,
1188 needsGC(E->getLHS()->getType()),
1189 AggValueSlot::IsAliased,
1190 AggValueSlot::MayOverlap),
1191 Dest);
1192 return;
1193 }
1194
1195 LValue LHS = CGF.EmitLValue(E->getLHS());
1196
1197 // If we have an atomic type, evaluate into the destination and then
1198 // do an atomic copy.
1199 if (LHS.getType()->isAtomicType() ||
1200 CGF.LValueIsSuitableForInlineAtomic(LHS)) {
1201 EnsureDest(E->getRHS()->getType());
1202 Visit(E->getRHS());
1203 CGF.EmitAtomicStore(Dest.asRValue(), LHS, /*isInit*/ false);
1204 return;
1205 }
1206
1207 // Codegen the RHS so that it stores directly into the LHS.
1208 AggValueSlot LHSSlot = AggValueSlot::forLValue(
1209 LHS, CGF, AggValueSlot::IsDestructed, needsGC(E->getLHS()->getType()),
1210 AggValueSlot::IsAliased, AggValueSlot::MayOverlap);
1211 // A non-volatile aggregate destination might have volatile member.
1212 if (!LHSSlot.isVolatile() &&
1213 CGF.hasVolatileMember(E->getLHS()->getType()))
1214 LHSSlot.setVolatile(true);
1215
1216 CGF.EmitAggExpr(E->getRHS(), LHSSlot);
1217
1218 // Copy into the destination if the assignment isn't ignored.
1219 EmitFinalDestCopy(E->getType(), LHS);
1220
1221 if (!Dest.isIgnored() && !Dest.isExternallyDestructed() &&
1222 E->getType().isDestructedType() == QualType::DK_nontrivial_c_struct)
1223 CGF.pushDestroy(QualType::DK_nontrivial_c_struct, Dest.getAddress(),
1224 E->getType());
1225}
1226
1227void AggExprEmitter::
1228VisitAbstractConditionalOperator(const AbstractConditionalOperator *E) {
1229 llvm::BasicBlock *LHSBlock = CGF.createBasicBlock("cond.true");
1230 llvm::BasicBlock *RHSBlock = CGF.createBasicBlock("cond.false");
1231 llvm::BasicBlock *ContBlock = CGF.createBasicBlock("cond.end");
1232
1233 // Bind the common expression if necessary.
1234 CodeGenFunction::OpaqueValueMapping binding(CGF, E);
1235
1236 CodeGenFunction::ConditionalEvaluation eval(CGF);
1237 CGF.EmitBranchOnBoolExpr(E->getCond(), LHSBlock, RHSBlock,
1238 CGF.getProfileCount(E));
1239
1240 // Save whether the destination's lifetime is externally managed.
1241 bool isExternallyDestructed = Dest.isExternallyDestructed();
1242 bool destructNonTrivialCStruct =
1243 !isExternallyDestructed &&
1244 E->getType().isDestructedType() == QualType::DK_nontrivial_c_struct;
1245 isExternallyDestructed |= destructNonTrivialCStruct;
1246 Dest.setExternallyDestructed(isExternallyDestructed);
1247
1248 eval.begin(CGF);
1249 CGF.EmitBlock(LHSBlock);
1250 CGF.incrementProfileCounter(E);
1251 Visit(E->getTrueExpr());
1252 eval.end(CGF);
1253
1254 assert(CGF.HaveInsertPoint() && "expression evaluation ended with no IP!");
1255 CGF.Builder.CreateBr(ContBlock);
1256
1257 // If the result of an agg expression is unused, then the emission
1258 // of the LHS might need to create a destination slot. That's fine
1259 // with us, and we can safely emit the RHS into the same slot, but
1260 // we shouldn't claim that it's already being destructed.
1261 Dest.setExternallyDestructed(isExternallyDestructed);
1262
1263 eval.begin(CGF);
1264 CGF.EmitBlock(RHSBlock);
1265 Visit(E->getFalseExpr());
1266 eval.end(CGF);
1267
1268 if (destructNonTrivialCStruct)
1269 CGF.pushDestroy(QualType::DK_nontrivial_c_struct, Dest.getAddress(),
1270 E->getType());
1271
1272 CGF.EmitBlock(ContBlock);
1273}
1274
1275void AggExprEmitter::VisitChooseExpr(const ChooseExpr *CE) {
1276 Visit(CE->getChosenSubExpr());
1277}
1278
1279void AggExprEmitter::VisitVAArgExpr(VAArgExpr *VE) {
1280 Address ArgValue = Address::invalid();
1281 Address ArgPtr = CGF.EmitVAArg(VE, ArgValue);
1282
1283 // If EmitVAArg fails, emit an error.
1284 if (!ArgPtr.isValid()) {
1285 CGF.ErrorUnsupported(VE, "aggregate va_arg expression");
1286 return;
1287 }
1288
1289 EmitFinalDestCopy(VE->getType(), CGF.MakeAddrLValue(ArgPtr, VE->getType()));
1290}
1291
1292void AggExprEmitter::VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E) {
1293 // Ensure that we have a slot, but if we already do, remember
1294 // whether it was externally destructed.
1295 bool wasExternallyDestructed = Dest.isExternallyDestructed();
1296 EnsureDest(E->getType());
1297
1298 // We're going to push a destructor if there isn't already one.
1299 Dest.setExternallyDestructed();
1300
1301 Visit(E->getSubExpr());
1302
1303 // Push that destructor we promised.
1304 if (!wasExternallyDestructed)
1305 CGF.EmitCXXTemporary(E->getTemporary(), E->getType(), Dest.getAddress());
1306}
1307
1308void
1309AggExprEmitter::VisitCXXConstructExpr(const CXXConstructExpr *E) {
1310 AggValueSlot Slot = EnsureSlot(E->getType());
1311 CGF.EmitCXXConstructExpr(E, Slot);
1312}
1313
1314void AggExprEmitter::VisitCXXInheritedCtorInitExpr(
1315 const CXXInheritedCtorInitExpr *E) {
1316 AggValueSlot Slot = EnsureSlot(E->getType());
1317 CGF.EmitInheritedCXXConstructorCall(
1318 E->getConstructor(), E->constructsVBase(), Slot.getAddress(),
1319 E->inheritedFromVBase(), E);
1320}
1321
1322void
1323AggExprEmitter::VisitLambdaExpr(LambdaExpr *E) {
1324 AggValueSlot Slot = EnsureSlot(E->getType());
1325 LValue SlotLV = CGF.MakeAddrLValue(Slot.getAddress(), E->getType());
1326
1327 // We'll need to enter cleanup scopes in case any of the element
1328 // initializers throws an exception.
1329 SmallVector<EHScopeStack::stable_iterator, 16> Cleanups;
1330 llvm::Instruction *CleanupDominator = nullptr;
1331
1332 CXXRecordDecl::field_iterator CurField = E->getLambdaClass()->field_begin();
1333 for (LambdaExpr::const_capture_init_iterator i = E->capture_init_begin(),
1334 e = E->capture_init_end();
1335 i != e; ++i, ++CurField) {
1336 // Emit initialization
1337 LValue LV = CGF.EmitLValueForFieldInitialization(SlotLV, *CurField);
1338 if (CurField->hasCapturedVLAType()) {
1339 CGF.EmitLambdaVLACapture(CurField->getCapturedVLAType(), LV);
1340 continue;
1341 }
1342
1343 EmitInitializationToLValue(*i, LV);
1344
1345 // Push a destructor if necessary.
1346 if (QualType::DestructionKind DtorKind =
1347 CurField->getType().isDestructedType()) {
1348 assert(LV.isSimple());
1349 if (CGF.needsEHCleanup(DtorKind)) {
1350 if (!CleanupDominator)
1351 CleanupDominator = CGF.Builder.CreateAlignedLoad(
1352 CGF.Int8Ty,
1353 llvm::Constant::getNullValue(CGF.Int8PtrTy),
1354 CharUnits::One()); // placeholder
1355
1356 CGF.pushDestroy(EHCleanup, LV.getAddress(CGF), CurField->getType(),
1357 CGF.getDestroyer(DtorKind), false);
1358 Cleanups.push_back(CGF.EHStack.stable_begin());
1359 }
1360 }
1361 }
1362
1363 // Deactivate all the partial cleanups in reverse order, which
1364 // generally means popping them.
1365 for (unsigned i = Cleanups.size(); i != 0; --i)
1366 CGF.DeactivateCleanupBlock(Cleanups[i-1], CleanupDominator);
1367
1368 // Destroy the placeholder if we made one.
1369 if (CleanupDominator)
1370 CleanupDominator->eraseFromParent();
1371}
1372
1373void AggExprEmitter::VisitExprWithCleanups(ExprWithCleanups *E) {
1374 CodeGenFunction::RunCleanupsScope cleanups(CGF);
1375 Visit(E->getSubExpr());
1376}
1377
1378void AggExprEmitter::VisitCXXScalarValueInitExpr(CXXScalarValueInitExpr *E) {
1379 QualType T = E->getType();
1380 AggValueSlot Slot = EnsureSlot(T);
1381 EmitNullInitializationToLValue(CGF.MakeAddrLValue(Slot.getAddress(), T));
1382}
1383
1384void AggExprEmitter::VisitImplicitValueInitExpr(ImplicitValueInitExpr *E) {
1385 QualType T = E->getType();
1386 AggValueSlot Slot = EnsureSlot(T);
1387 EmitNullInitializationToLValue(CGF.MakeAddrLValue(Slot.getAddress(), T));
1388}
1389
1390/// Determine whether the given cast kind is known to always convert values
1391/// with all zero bits in their value representation to values with all zero
1392/// bits in their value representation.
1393static bool castPreservesZero(const CastExpr *CE) {
1394 switch (CE->getCastKind()) {
1395 // No-ops.
1396 case CK_NoOp:
1397 case CK_UserDefinedConversion:
1398 case CK_ConstructorConversion:
1399 case CK_BitCast:
1400 case CK_ToUnion:
1401 case CK_ToVoid:
1402 // Conversions between (possibly-complex) integral, (possibly-complex)
1403 // floating-point, and bool.
1404 case CK_BooleanToSignedIntegral:
1405 case CK_FloatingCast:
1406 case CK_FloatingComplexCast:
1407 case CK_FloatingComplexToBoolean:
1408 case CK_FloatingComplexToIntegralComplex:
1409 case CK_FloatingComplexToReal:
1410 case CK_FloatingRealToComplex:
1411 case CK_FloatingToBoolean:
1412 case CK_FloatingToIntegral:
1413 case CK_IntegralCast:
1414 case CK_IntegralComplexCast:
1415 case CK_IntegralComplexToBoolean:
1416 case CK_IntegralComplexToFloatingComplex:
1417 case CK_IntegralComplexToReal:
1418 case CK_IntegralRealToComplex:
1419 case CK_IntegralToBoolean:
1420 case CK_IntegralToFloating:
1421 // Reinterpreting integers as pointers and vice versa.
1422 case CK_IntegralToPointer:
1423 case CK_PointerToIntegral:
1424 // Language extensions.
1425 case CK_VectorSplat:
1426 case CK_MatrixCast:
1427 case CK_NonAtomicToAtomic:
1428 case CK_AtomicToNonAtomic:
1429 return true;
1430
1431 case CK_BaseToDerivedMemberPointer:
1432 case CK_DerivedToBaseMemberPointer:
1433 case CK_MemberPointerToBoolean:
1434 case CK_NullToMemberPointer:
1435 case CK_ReinterpretMemberPointer:
1436 // FIXME: ABI-dependent.
1437 return false;
1438
1439 case CK_AnyPointerToBlockPointerCast:
1440 case CK_BlockPointerToObjCPointerCast:
1441 case CK_CPointerToObjCPointerCast:
1442 case CK_ObjCObjectLValueCast:
1443 case CK_IntToOCLSampler:
1444 case CK_ZeroToOCLOpaqueType:
1445 // FIXME: Check these.
1446 return false;
1447
1448 case CK_FixedPointCast:
1449 case CK_FixedPointToBoolean:
1450 case CK_FixedPointToFloating:
1451 case CK_FixedPointToIntegral:
1452 case CK_FloatingToFixedPoint:
1453 case CK_IntegralToFixedPoint:
1454 // FIXME: Do all fixed-point types represent zero as all 0 bits?
1455 return false;
1456
1457 case CK_AddressSpaceConversion:
1458 case CK_BaseToDerived:
1459 case CK_DerivedToBase:
1460 case CK_Dynamic:
1461 case CK_NullToPointer:
1462 case CK_PointerToBoolean:
1463 // FIXME: Preserves zeroes only if zero pointers and null pointers have the
1464 // same representation in all involved address spaces.
1465 return false;
1466
1467 case CK_ARCConsumeObject:
1468 case CK_ARCExtendBlockObject:
1469 case CK_ARCProduceObject:
1470 case CK_ARCReclaimReturnedObject:
1471 case CK_CopyAndAutoreleaseBlockObject:
1472 case CK_ArrayToPointerDecay:
1473 case CK_FunctionToPointerDecay:
1474 case CK_BuiltinFnToFnPtr:
1475 case CK_Dependent:
1476 case CK_LValueBitCast:
1477 case CK_LValueToRValue:
1478 case CK_LValueToRValueBitCast:
1479 case CK_UncheckedDerivedToBase:
1480 return false;
1481 }
1482 llvm_unreachable("Unhandled clang::CastKind enum");
1483}
1484
1485/// isSimpleZero - If emitting this value will obviously just cause a store of
1486/// zero to memory, return true. This can return false if uncertain, so it just
1487/// handles simple cases.
1488static bool isSimpleZero(const Expr *E, CodeGenFunction &CGF) {
1489 E = E->IgnoreParens();
1490 while (auto *CE = dyn_cast<CastExpr>(E)) {
1491 if (!castPreservesZero(CE))
1492 break;
1493 E = CE->getSubExpr()->IgnoreParens();
1494 }
1495
1496 // 0
1497 if (const IntegerLiteral *IL = dyn_cast<IntegerLiteral>(E))
1498 return IL->getValue() == 0;
1499 // +0.0
1500 if (const FloatingLiteral *FL = dyn_cast<FloatingLiteral>(E))
1501 return FL->getValue().isPosZero();
1502 // int()
1503 if ((isa<ImplicitValueInitExpr>(E) || isa<CXXScalarValueInitExpr>(E)) &&
1504 CGF.getTypes().isZeroInitializable(E->getType()))
1505 return true;
1506 // (int*)0 - Null pointer expressions.
1507 if (const CastExpr *ICE = dyn_cast<CastExpr>(E))
1508 return ICE->getCastKind() == CK_NullToPointer &&
1509 CGF.getTypes().isPointerZeroInitializable(E->getType()) &&
1510 !E->HasSideEffects(CGF.getContext());
1511 // '\0'
1512 if (const CharacterLiteral *CL = dyn_cast<CharacterLiteral>(E))
1513 return CL->getValue() == 0;
1514
1515 // Otherwise, hard case: conservatively return false.
1516 return false;
1517}
1518
1519
1520void
1521AggExprEmitter::EmitInitializationToLValue(Expr *E, LValue LV) {
1522 QualType type = LV.getType();
1523 // FIXME: Ignore result?
1524 // FIXME: Are initializers affected by volatile?
1525 if (Dest.isZeroed() && isSimpleZero(E, CGF)) {
1526 // Storing "i32 0" to a zero'd memory location is a noop.
1527 return;
1528 } else if (isa<ImplicitValueInitExpr>(E) || isa<CXXScalarValueInitExpr>(E)) {
1529 return EmitNullInitializationToLValue(LV);
1530 } else if (isa<NoInitExpr>(E)) {
1531 // Do nothing.
1532 return;
1533 } else if (type->isReferenceType()) {
1534 RValue RV = CGF.EmitReferenceBindingToExpr(E);
1535 return CGF.EmitStoreThroughLValue(RV, LV);
1536 }
1537
1538 switch (CGF.getEvaluationKind(type)) {
1539 case TEK_Complex:
1540 CGF.EmitComplexExprIntoLValue(E, LV, /*isInit*/ true);
1541 return;
1542 case TEK_Aggregate:
1543 CGF.EmitAggExpr(
1544 E, AggValueSlot::forLValue(LV, CGF, AggValueSlot::IsDestructed,
1545 AggValueSlot::DoesNotNeedGCBarriers,
1546 AggValueSlot::IsNotAliased,
1547 AggValueSlot::MayOverlap, Dest.isZeroed()));
1548 return;
1549 case TEK_Scalar:
1550 if (LV.isSimple()) {
1551 CGF.EmitScalarInit(E, /*D=*/nullptr, LV, /*Captured=*/false);
1552 } else {
1553 CGF.EmitStoreThroughLValue(RValue::get(CGF.EmitScalarExpr(E)), LV);
1554 }
1555 return;
1556 }
1557 llvm_unreachable("bad evaluation kind");
1558}
1559
1560void AggExprEmitter::EmitNullInitializationToLValue(LValue lv) {
1561 QualType type = lv.getType();
1562
1563 // If the destination slot is already zeroed out before the aggregate is
1564 // copied into it, we don't have to emit any zeros here.
1565 if (Dest.isZeroed() && CGF.getTypes().isZeroInitializable(type))
1566 return;
1567
1568 if (CGF.hasScalarEvaluationKind(type)) {
1569 // For non-aggregates, we can store the appropriate null constant.
1570 llvm::Value *null = CGF.CGM.EmitNullConstant(type);
1571 // Note that the following is not equivalent to
1572 // EmitStoreThroughBitfieldLValue for ARC types.
1573 if (lv.isBitField()) {
1574 CGF.EmitStoreThroughBitfieldLValue(RValue::get(null), lv);
1575 } else {
1576 assert(lv.isSimple());
1577 CGF.EmitStoreOfScalar(null, lv, /* isInitialization */ true);
1578 }
1579 } else {
1580 // There's a potential optimization opportunity in combining
1581 // memsets; that would be easy for arrays, but relatively
1582 // difficult for structures with the current code.
1583 CGF.EmitNullInitialization(lv.getAddress(CGF), lv.getType());
1584 }
1585}
1586
1587void AggExprEmitter::VisitInitListExpr(InitListExpr *E) {
1588#if 0
1589 // FIXME: Assess perf here? Figure out what cases are worth optimizing here
1590 // (Length of globals? Chunks of zeroed-out space?).
1591 //
1592 // If we can, prefer a copy from a global; this is a lot less code for long
1593 // globals, and it's easier for the current optimizers to analyze.
1594 if (llvm::Constant* C = CGF.CGM.EmitConstantExpr(E, E->getType(), &CGF)) {
1595 llvm::GlobalVariable* GV =
1596 new llvm::GlobalVariable(CGF.CGM.getModule(), C->getType(), true,
1597 llvm::GlobalValue::InternalLinkage, C, "");
1598 EmitFinalDestCopy(E->getType(), CGF.MakeAddrLValue(GV, E->getType()));
1599 return;
1600 }
1601#endif
1602 if (E->hadArrayRangeDesignator())
1603 CGF.ErrorUnsupported(E, "GNU array range designator extension");
1604
1605 if (E->isTransparent())
1606 return Visit(E->getInit(0));
1607
1608 AggValueSlot Dest = EnsureSlot(E->getType());
1609
1610 LValue DestLV = CGF.MakeAddrLValue(Dest.getAddress(), E->getType());
1611
1612 // Handle initialization of an array.
1613 if (E->getType()->isArrayType()) {
1614 auto AType = cast<llvm::ArrayType>(Dest.getAddress().getElementType());
1615 EmitArrayInit(Dest.getAddress(), AType, E->getType(), E);
1616 return;
1617 }
1618
1619 assert(E->getType()->isRecordType() && "Only support structs/unions here!");
1620
1621 // Do struct initialization; this code just sets each individual member
1622 // to the approprate value. This makes bitfield support automatic;
1623 // the disadvantage is that the generated code is more difficult for
1624 // the optimizer, especially with bitfields.
1625 unsigned NumInitElements = E->getNumInits();
1626 RecordDecl *record = E->getType()->castAs<RecordType>()->getDecl();
1627
1628 // We'll need to enter cleanup scopes in case any of the element
1629 // initializers throws an exception.
1630 SmallVector<EHScopeStack::stable_iterator, 16> cleanups;
1631 llvm::Instruction *cleanupDominator = nullptr;
1632 auto addCleanup = [&](const EHScopeStack::stable_iterator &cleanup) {
1633 cleanups.push_back(cleanup);
1634 if (!cleanupDominator) // create placeholder once needed
1635 cleanupDominator = CGF.Builder.CreateAlignedLoad(
1636 CGF.Int8Ty, llvm::Constant::getNullValue(CGF.Int8PtrTy),
1637 CharUnits::One());
1638 };
1639
1640 unsigned curInitIndex = 0;
1641
1642 // Emit initialization of base classes.
1643 if (auto *CXXRD = dyn_cast<CXXRecordDecl>(record)) {
1644 assert(E->getNumInits() >= CXXRD->getNumBases() &&
1645 "missing initializer for base class");
1646 for (auto &Base : CXXRD->bases()) {
1647 assert(!Base.isVirtual() && "should not see vbases here");
1648 auto *BaseRD = Base.getType()->getAsCXXRecordDecl();
1649 Address V = CGF.GetAddressOfDirectBaseInCompleteClass(
1650 Dest.getAddress(), CXXRD, BaseRD,
1651 /*isBaseVirtual*/ false);
1652 AggValueSlot AggSlot = AggValueSlot::forAddr(
1653 V, Qualifiers(),
1654 AggValueSlot::IsDestructed,
1655 AggValueSlot::DoesNotNeedGCBarriers,
1656 AggValueSlot::IsNotAliased,
1657 CGF.getOverlapForBaseInit(CXXRD, BaseRD, Base.isVirtual()));
1658 CGF.EmitAggExpr(E->getInit(curInitIndex++), AggSlot);
1659
1660 if (QualType::DestructionKind dtorKind =
1661 Base.getType().isDestructedType()) {
1662 CGF.pushDestroy(dtorKind, V, Base.getType());
1663 addCleanup(CGF.EHStack.stable_begin());
1664 }
1665 }
1666 }
1667
1668 // Prepare a 'this' for CXXDefaultInitExprs.
1669 CodeGenFunction::FieldConstructionScope FCS(CGF, Dest.getAddress());
1670
1671 if (record->isUnion()) {
1672 // Only initialize one field of a union. The field itself is
1673 // specified by the initializer list.
1674 if (!E->getInitializedFieldInUnion()) {
1675 // Empty union; we have nothing to do.
1676
1677#ifndef NDEBUG
1678 // Make sure that it's really an empty and not a failure of
1679 // semantic analysis.
1680 for (const auto *Field : record->fields())
1681 assert(Field->isUnnamedBitfield() && "Only unnamed bitfields allowed");
1682#endif
1683 return;
1684 }
1685
1686 // FIXME: volatility
1687 FieldDecl *Field = E->getInitializedFieldInUnion();
1688
1689 LValue FieldLoc = CGF.EmitLValueForFieldInitialization(DestLV, Field);
1690 if (NumInitElements) {
1691 // Store the initializer into the field
1692 EmitInitializationToLValue(E->getInit(0), FieldLoc);
1693 } else {
1694 // Default-initialize to null.
1695 EmitNullInitializationToLValue(FieldLoc);
1696 }
1697
1698 return;
1699 }
1700
1701 // Here we iterate over the fields; this makes it simpler to both
1702 // default-initialize fields and skip over unnamed fields.
1703 for (const auto *field : record->fields()) {
1704 // We're done once we hit the flexible array member.
1705 if (field->getType()->isIncompleteArrayType())
1706 break;
1707
1708 // Always skip anonymous bitfields.
1709 if (field->isUnnamedBitfield())
1710 continue;
1711
1712 // We're done if we reach the end of the explicit initializers, we
1713 // have a zeroed object, and the rest of the fields are
1714 // zero-initializable.
1715 if (curInitIndex == NumInitElements && Dest.isZeroed() &&
1716 CGF.getTypes().isZeroInitializable(E->getType()))
1717 break;
1718
1719
1720 LValue LV = CGF.EmitLValueForFieldInitialization(DestLV, field);
1721 // We never generate write-barries for initialized fields.
1722 LV.setNonGC(true);
1723
1724 if (curInitIndex < NumInitElements) {
1725 // Store the initializer into the field.
1726 EmitInitializationToLValue(E->getInit(curInitIndex++), LV);
1727 } else {
1728 // We're out of initializers; default-initialize to null
1729 EmitNullInitializationToLValue(LV);
1730 }
1731
1732 // Push a destructor if necessary.
1733 // FIXME: if we have an array of structures, all explicitly
1734 // initialized, we can end up pushing a linear number of cleanups.
1735 bool pushedCleanup = false;
1736 if (QualType::DestructionKind dtorKind
1737 = field->getType().isDestructedType()) {
1738 assert(LV.isSimple());
1739 if (CGF.needsEHCleanup(dtorKind)) {
1740 CGF.pushDestroy(EHCleanup, LV.getAddress(CGF), field->getType(),
1741 CGF.getDestroyer(dtorKind), false);
1742 addCleanup(CGF.EHStack.stable_begin());
1743 pushedCleanup = true;
1744 }
1745 }
1746
1747 // If the GEP didn't get used because of a dead zero init or something
1748 // else, clean it up for -O0 builds and general tidiness.
1749 if (!pushedCleanup && LV.isSimple())
1750 if (llvm::GetElementPtrInst *GEP =
1751 dyn_cast<llvm::GetElementPtrInst>(LV.getPointer(CGF)))
1752 if (GEP->use_empty())
1753 GEP->eraseFromParent();
1754 }
1755
1756 // Deactivate all the partial cleanups in reverse order, which
1757 // generally means popping them.
1758 assert((cleanupDominator || cleanups.empty()) &&
1759 "Missing cleanupDominator before deactivating cleanup blocks");
1760 for (unsigned i = cleanups.size(); i != 0; --i)
1761 CGF.DeactivateCleanupBlock(cleanups[i-1], cleanupDominator);
1762
1763 // Destroy the placeholder if we made one.
1764 if (cleanupDominator)
1765 cleanupDominator->eraseFromParent();
1766}
1767
1768void AggExprEmitter::VisitArrayInitLoopExpr(const ArrayInitLoopExpr *E,
1769 llvm::Value *outerBegin) {
1770 // Emit the common subexpression.
1771 CodeGenFunction::OpaqueValueMapping binding(CGF, E->getCommonExpr());
1772
1773 Address destPtr = EnsureSlot(E->getType()).getAddress();
1774 uint64_t numElements = E->getArraySize().getZExtValue();
1775
1776 if (!numElements)
1777 return;
1778
1779 // destPtr is an array*. Construct an elementType* by drilling down a level.
1780 llvm::Value *zero = llvm::ConstantInt::get(CGF.SizeTy, 0);
1781 llvm::Value *indices[] = {zero, zero};
1782 llvm::Value *begin = Builder.CreateInBoundsGEP(destPtr.getPointer(), indices,
1783 "arrayinit.begin");
1784
1785 // Prepare to special-case multidimensional array initialization: we avoid
1786 // emitting multiple destructor loops in that case.
1787 if (!outerBegin)
1788 outerBegin = begin;
1789 ArrayInitLoopExpr *InnerLoop = dyn_cast<ArrayInitLoopExpr>(E->getSubExpr());
1790
1791 QualType elementType =
1792 CGF.getContext().getAsArrayType(E->getType())->getElementType();
1793 CharUnits elementSize = CGF.getContext().getTypeSizeInChars(elementType);
1794 CharUnits elementAlign =
1795 destPtr.getAlignment().alignmentOfArrayElement(elementSize);
1796
1797 llvm::BasicBlock *entryBB = Builder.GetInsertBlock();
1798 llvm::BasicBlock *bodyBB = CGF.createBasicBlock("arrayinit.body");
1799
1800 // Jump into the body.
1801 CGF.EmitBlock(bodyBB);
1802 llvm::PHINode *index =
1803 Builder.CreatePHI(zero->getType(), 2, "arrayinit.index");
1804 index->addIncoming(zero, entryBB);
1805 llvm::Value *element = Builder.CreateInBoundsGEP(begin, index);
1806
1807 // Prepare for a cleanup.
1808 QualType::DestructionKind dtorKind = elementType.isDestructedType();
1809 EHScopeStack::stable_iterator cleanup;
1810 if (CGF.needsEHCleanup(dtorKind) && !InnerLoop) {
1811 if (outerBegin->getType() != element->getType())
1812 outerBegin = Builder.CreateBitCast(outerBegin, element->getType());
1813 CGF.pushRegularPartialArrayCleanup(outerBegin, element, elementType,
1814 elementAlign,
1815 CGF.getDestroyer(dtorKind));
1816 cleanup = CGF.EHStack.stable_begin();
1817 } else {
1818 dtorKind = QualType::DK_none;
1819 }
1820
1821 // Emit the actual filler expression.
1822 {
1823 // Temporaries created in an array initialization loop are destroyed
1824 // at the end of each iteration.
1825 CodeGenFunction::RunCleanupsScope CleanupsScope(CGF);
1826 CodeGenFunction::ArrayInitLoopExprScope Scope(CGF, index);
1827 LValue elementLV =
1828 CGF.MakeAddrLValue(Address(element, elementAlign), elementType);
1829
1830 if (InnerLoop) {
1831 // If the subexpression is an ArrayInitLoopExpr, share its cleanup.
1832 auto elementSlot = AggValueSlot::forLValue(
1833 elementLV, CGF, AggValueSlot::IsDestructed,
1834 AggValueSlot::DoesNotNeedGCBarriers, AggValueSlot::IsNotAliased,
1835 AggValueSlot::DoesNotOverlap);
1836 AggExprEmitter(CGF, elementSlot, false)
1837 .VisitArrayInitLoopExpr(InnerLoop, outerBegin);
1838 } else
1839 EmitInitializationToLValue(E->getSubExpr(), elementLV);
1840 }
1841
1842 // Move on to the next element.
1843 llvm::Value *nextIndex = Builder.CreateNUWAdd(
1844 index, llvm::ConstantInt::get(CGF.SizeTy, 1), "arrayinit.next");
1845 index->addIncoming(nextIndex, Builder.GetInsertBlock());
1846
1847 // Leave the loop if we're done.
1848 llvm::Value *done = Builder.CreateICmpEQ(
1849 nextIndex, llvm::ConstantInt::get(CGF.SizeTy, numElements),
1850 "arrayinit.done");
1851 llvm::BasicBlock *endBB = CGF.createBasicBlock("arrayinit.end");
1852 Builder.CreateCondBr(done, endBB, bodyBB);
1853
1854 CGF.EmitBlock(endBB);
1855
1856 // Leave the partial-array cleanup if we entered one.
1857 if (dtorKind)
1858 CGF.DeactivateCleanupBlock(cleanup, index);
1859}
1860
1861void AggExprEmitter::VisitDesignatedInitUpdateExpr(DesignatedInitUpdateExpr *E) {
1862 AggValueSlot Dest = EnsureSlot(E->getType());
1863
1864 LValue DestLV = CGF.MakeAddrLValue(Dest.getAddress(), E->getType());
1865 EmitInitializationToLValue(E->getBase(), DestLV);
1866 VisitInitListExpr(E->getUpdater());
1867}
1868
1869//===----------------------------------------------------------------------===//
1870// Entry Points into this File
1871//===----------------------------------------------------------------------===//
1872
1873/// GetNumNonZeroBytesInInit - Get an approximate count of the number of
1874/// non-zero bytes that will be stored when outputting the initializer for the
1875/// specified initializer expression.
1876static CharUnits GetNumNonZeroBytesInInit(const Expr *E, CodeGenFunction &CGF) {
1877 if (auto *MTE = dyn_cast<MaterializeTemporaryExpr>(E))
1878 E = MTE->getSubExpr();
1879 E = E->IgnoreParenNoopCasts(CGF.getContext());
1880
1881 // 0 and 0.0 won't require any non-zero stores!
1882 if (isSimpleZero(E, CGF)) return CharUnits::Zero();
1883
1884 // If this is an initlist expr, sum up the size of sizes of the (present)
1885 // elements. If this is something weird, assume the whole thing is non-zero.
1886 const InitListExpr *ILE = dyn_cast<InitListExpr>(E);
1887 while (ILE && ILE->isTransparent())
1888 ILE = dyn_cast<InitListExpr>(ILE->getInit(0));
1889 if (!ILE || !CGF.getTypes().isZeroInitializable(ILE->getType()))
1890 return CGF.getContext().getTypeSizeInChars(E->getType());
1891
1892 // InitListExprs for structs have to be handled carefully. If there are
1893 // reference members, we need to consider the size of the reference, not the
1894 // referencee. InitListExprs for unions and arrays can't have references.
1895 if (const RecordType *RT = E->getType()->getAs<RecordType>()) {
1896 if (!RT->isUnionType()) {
1897 RecordDecl *SD = RT->getDecl();
1898 CharUnits NumNonZeroBytes = CharUnits::Zero();
1899
1900 unsigned ILEElement = 0;
1901 if (auto *CXXRD = dyn_cast<CXXRecordDecl>(SD))
1902 while (ILEElement != CXXRD->getNumBases())
1903 NumNonZeroBytes +=
1904 GetNumNonZeroBytesInInit(ILE->getInit(ILEElement++), CGF);
1905 for (const auto *Field : SD->fields()) {
1906 // We're done once we hit the flexible array member or run out of
1907 // InitListExpr elements.
1908 if (Field->getType()->isIncompleteArrayType() ||
1909 ILEElement == ILE->getNumInits())
1910 break;
1911 if (Field->isUnnamedBitfield())
1912 continue;
1913
1914 const Expr *E = ILE->getInit(ILEElement++);
1915
1916 // Reference values are always non-null and have the width of a pointer.
1917 if (Field->getType()->isReferenceType())
1918 NumNonZeroBytes += CGF.getContext().toCharUnitsFromBits(
1919 CGF.getTarget().getPointerWidth(0));
1920 else
1921 NumNonZeroBytes += GetNumNonZeroBytesInInit(E, CGF);
1922 }
1923
1924 return NumNonZeroBytes;
1925 }
1926 }
1927
1928 // FIXME: This overestimates the number of non-zero bytes for bit-fields.
1929 CharUnits NumNonZeroBytes = CharUnits::Zero();
1930 for (unsigned i = 0, e = ILE->getNumInits(); i != e; ++i)
1931 NumNonZeroBytes += GetNumNonZeroBytesInInit(ILE->getInit(i), CGF);
1932 return NumNonZeroBytes;
1933}
1934
1935/// CheckAggExprForMemSetUse - If the initializer is large and has a lot of
1936/// zeros in it, emit a memset and avoid storing the individual zeros.
1937///
1938static void CheckAggExprForMemSetUse(AggValueSlot &Slot, const Expr *E,
1939 CodeGenFunction &CGF) {
1940 // If the slot is already known to be zeroed, nothing to do. Don't mess with
1941 // volatile stores.
1942 if (Slot.isZeroed() || Slot.isVolatile() || !Slot.getAddress().isValid())
1943 return;
1944
1945 // C++ objects with a user-declared constructor don't need zero'ing.
1946 if (CGF.getLangOpts().CPlusPlus)
1947 if (const RecordType *RT = CGF.getContext()
1948 .getBaseElementType(E->getType())->getAs<RecordType>()) {
1949 const CXXRecordDecl *RD = cast<CXXRecordDecl>(RT->getDecl());
1950 if (RD->hasUserDeclaredConstructor())
1951 return;
1952 }
1953
1954 // If the type is 16-bytes or smaller, prefer individual stores over memset.
1955 CharUnits Size = Slot.getPreferredSize(CGF.getContext(), E->getType());
1956 if (Size <= CharUnits::fromQuantity(16))
1957 return;
1958
1959 // Check to see if over 3/4 of the initializer are known to be zero. If so,
1960 // we prefer to emit memset + individual stores for the rest.
1961 CharUnits NumNonZeroBytes = GetNumNonZeroBytesInInit(E, CGF);
1962 if (NumNonZeroBytes*4 > Size)
1963 return;
1964
1965 // Okay, it seems like a good idea to use an initial memset, emit the call.
1966 llvm::Constant *SizeVal = CGF.Builder.getInt64(Size.getQuantity());
1967
1968 Address Loc = Slot.getAddress();
1969 Loc = CGF.Builder.CreateElementBitCast(Loc, CGF.Int8Ty);
1970 CGF.Builder.CreateMemSet(Loc, CGF.Builder.getInt8(0), SizeVal, false);
1971
1972 // Tell the AggExprEmitter that the slot is known zero.
1973 Slot.setZeroed();
1974}
1975
1976
1977
1978
1979/// EmitAggExpr - Emit the computation of the specified expression of aggregate
1980/// type. The result is computed into DestPtr. Note that if DestPtr is null,
1981/// the value of the aggregate expression is not needed. If VolatileDest is
1982/// true, DestPtr cannot be 0.
1983void CodeGenFunction::EmitAggExpr(const Expr *E, AggValueSlot Slot) {
1984 assert(E && hasAggregateEvaluationKind(E->getType()) &&
1985 "Invalid aggregate expression to emit");
1986 assert((Slot.getAddress().isValid() || Slot.isIgnored()) &&
1987 "slot has bits but no address");
1988
1989 // Optimize the slot if possible.
1990 CheckAggExprForMemSetUse(Slot, E, *this);
1991
1992 AggExprEmitter(*this, Slot, Slot.isIgnored()).Visit(const_cast<Expr*>(E));
1993}
1994
1995LValue CodeGenFunction::EmitAggExprToLValue(const Expr *E) {
1996