CGExprAgg.cpp revision db45806b991013280a03057025c9538de64d5dfb 
1//===--- CGExprAgg.cpp - Emit LLVM Code from Aggregate Expressions --------===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// This contains code to emit Aggregate Expr nodes as LLVM code.
11//
12//===----------------------------------------------------------------------===//
13
14#include "CodeGenFunction.h"
15#include "CodeGenModule.h"
16#include "CGObjCRuntime.h"
17#include "clang/AST/ASTContext.h"
18#include "clang/AST/DeclCXX.h"
19#include "clang/AST/StmtVisitor.h"
20#include "llvm/Constants.h"
21#include "llvm/Function.h"
22#include "llvm/GlobalVariable.h"
23#include "llvm/Intrinsics.h"
24using namespace clang;
25using namespace CodeGen;
26
27//===----------------------------------------------------------------------===//
28//                        Aggregate Expression Emitter
29//===----------------------------------------------------------------------===//
30
31namespace  {
32class AggExprEmitter : public StmtVisitor<AggExprEmitter> {
33  CodeGenFunction &CGF;
34  CGBuilderTy &Builder;
35  AggValueSlot Dest;
36  bool IgnoreResult;
37
38  /// We want to use 'dest' as the return slot except under two
39  /// conditions:
40  ///   - The destination slot requires garbage collection, so we
41  ///     need to use the GC API.
42  ///   - The destination slot is potentially aliased.
43  bool shouldUseDestForReturnSlot() const {
44    return !(Dest.requiresGCollection() || Dest.isPotentiallyAliased());
45  }
46
47  ReturnValueSlot getReturnValueSlot() const {
48    if (!shouldUseDestForReturnSlot())
49      return ReturnValueSlot();
50
51    return ReturnValueSlot(Dest.getAddr(), Dest.isVolatile());
52  }
53
54  AggValueSlot EnsureSlot(QualType T) {
55    if (!Dest.isIgnored()) return Dest;
56    return CGF.CreateAggTemp(T, "agg.tmp.ensured");
57  }
58
59public:
60  AggExprEmitter(CodeGenFunction &cgf, AggValueSlot Dest,
61                 bool ignore)
62    : CGF(cgf), Builder(CGF.Builder), Dest(Dest),
63      IgnoreResult(ignore) {
64  }
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  /// EmitFinalDestCopy - Perform the final copy to DestPtr, if desired.
76  void EmitFinalDestCopy(const Expr *E, LValue Src, bool Ignore = false);
77  void EmitFinalDestCopy(const Expr *E, RValue Src, bool Ignore = false);
78
79  void EmitMoveFromReturnSlot(const Expr *E, RValue Src);
80
81  AggValueSlot::NeedsGCBarriers_t needsGC(QualType T) {
82    if (CGF.getLangOptions().getGC() && TypeRequiresGCollection(T))
83      return AggValueSlot::NeedsGCBarriers;
84    return AggValueSlot::DoesNotNeedGCBarriers;
85  }
86
87  bool TypeRequiresGCollection(QualType T);
88
89  //===--------------------------------------------------------------------===//
90  //                            Visitor Methods
91  //===--------------------------------------------------------------------===//
92
93  void VisitStmt(Stmt *S) {
94    CGF.ErrorUnsupported(S, "aggregate expression");
95  }
96  void VisitParenExpr(ParenExpr *PE) { Visit(PE->getSubExpr()); }
97  void VisitGenericSelectionExpr(GenericSelectionExpr *GE) {
98    Visit(GE->getResultExpr());
99  }
100  void VisitUnaryExtension(UnaryOperator *E) { Visit(E->getSubExpr()); }
101  void VisitSubstNonTypeTemplateParmExpr(SubstNonTypeTemplateParmExpr *E) {
102    return Visit(E->getReplacement());
103  }
104
105  // l-values.
106  void VisitDeclRefExpr(DeclRefExpr *DRE) { EmitAggLoadOfLValue(DRE); }
107  void VisitMemberExpr(MemberExpr *ME) { EmitAggLoadOfLValue(ME); }
108  void VisitUnaryDeref(UnaryOperator *E) { EmitAggLoadOfLValue(E); }
109  void VisitStringLiteral(StringLiteral *E) { EmitAggLoadOfLValue(E); }
110  void VisitCompoundLiteralExpr(CompoundLiteralExpr *E);
111  void VisitArraySubscriptExpr(ArraySubscriptExpr *E) {
112    EmitAggLoadOfLValue(E);
113  }
114  void VisitBlockDeclRefExpr(const BlockDeclRefExpr *E) {
115    EmitAggLoadOfLValue(E);
116  }
117  void VisitPredefinedExpr(const PredefinedExpr *E) {
118    EmitAggLoadOfLValue(E);
119  }
120
121  // Operators.
122  void VisitCastExpr(CastExpr *E);
123  void VisitCallExpr(const CallExpr *E);
124  void VisitStmtExpr(const StmtExpr *E);
125  void VisitBinaryOperator(const BinaryOperator *BO);
126  void VisitPointerToDataMemberBinaryOperator(const BinaryOperator *BO);
127  void VisitBinAssign(const BinaryOperator *E);
128  void VisitBinComma(const BinaryOperator *E);
129
130  void VisitObjCMessageExpr(ObjCMessageExpr *E);
131  void VisitObjCIvarRefExpr(ObjCIvarRefExpr *E) {
132    EmitAggLoadOfLValue(E);
133  }
134
135  void VisitAbstractConditionalOperator(const AbstractConditionalOperator *CO);
136  void VisitChooseExpr(const ChooseExpr *CE);
137  void VisitInitListExpr(InitListExpr *E);
138  void VisitImplicitValueInitExpr(ImplicitValueInitExpr *E);
139  void VisitCXXDefaultArgExpr(CXXDefaultArgExpr *DAE) {
140    Visit(DAE->getExpr());
141  }
142  void VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E);
143  void VisitCXXConstructExpr(const CXXConstructExpr *E);
144  void VisitExprWithCleanups(ExprWithCleanups *E);
145  void VisitCXXScalarValueInitExpr(CXXScalarValueInitExpr *E);
146  void VisitCXXTypeidExpr(CXXTypeidExpr *E) { EmitAggLoadOfLValue(E); }
147  void VisitMaterializeTemporaryExpr(MaterializeTemporaryExpr *E);
148  void VisitOpaqueValueExpr(OpaqueValueExpr *E);
149
150  void VisitPseudoObjectExpr(PseudoObjectExpr *E) {
151    if (E->isGLValue()) {
152      LValue LV = CGF.EmitPseudoObjectLValue(E);
153      return EmitFinalDestCopy(E, LV);
154    }
155
156    CGF.EmitPseudoObjectRValue(E, EnsureSlot(E->getType()));
157  }
158
159  void VisitVAArgExpr(VAArgExpr *E);
160
161  void EmitInitializationToLValue(Expr *E, LValue Address);
162  void EmitNullInitializationToLValue(LValue Address);
163  //  case Expr::ChooseExprClass:
164  void VisitCXXThrowExpr(const CXXThrowExpr *E) { CGF.EmitCXXThrowExpr(E); }
165  void VisitAtomicExpr(AtomicExpr *E) {
166    CGF.EmitAtomicExpr(E, EnsureSlot(E->getType()).getAddr());
167  }
168};
169}  // end anonymous namespace.
170
171//===----------------------------------------------------------------------===//
172//                                Utilities
173//===----------------------------------------------------------------------===//
174
175/// EmitAggLoadOfLValue - Given an expression with aggregate type that
176/// represents a value lvalue, this method emits the address of the lvalue,
177/// then loads the result into DestPtr.
178void AggExprEmitter::EmitAggLoadOfLValue(const Expr *E) {
179  LValue LV = CGF.EmitLValue(E);
180  EmitFinalDestCopy(E, LV);
181}
182
183/// \brief True if the given aggregate type requires special GC API calls.
184bool AggExprEmitter::TypeRequiresGCollection(QualType T) {
185  // Only record types have members that might require garbage collection.
186  const RecordType *RecordTy = T->getAs<RecordType>();
187  if (!RecordTy) return false;
188
189  // Don't mess with non-trivial C++ types.
190  RecordDecl *Record = RecordTy->getDecl();
191  if (isa<CXXRecordDecl>(Record) &&
192      (!cast<CXXRecordDecl>(Record)->hasTrivialCopyConstructor() ||
193       !cast<CXXRecordDecl>(Record)->hasTrivialDestructor()))
194    return false;
195
196  // Check whether the type has an object member.
197  return Record->hasObjectMember();
198}
199
200/// \brief Perform the final move to DestPtr if for some reason
201/// getReturnValueSlot() didn't use it directly.
202///
203/// The idea is that you do something like this:
204///   RValue Result = EmitSomething(..., getReturnValueSlot());
205///   EmitMoveFromReturnSlot(E, Result);
206///
207/// If nothing interferes, this will cause the result to be emitted
208/// directly into the return value slot.  Otherwise, a final move
209/// will be performed.
210void AggExprEmitter::EmitMoveFromReturnSlot(const Expr *E, RValue Src) {
211  if (shouldUseDestForReturnSlot()) {
212    // Logically, Dest.getAddr() should equal Src.getAggregateAddr().
213    // The possibility of undef rvalues complicates that a lot,
214    // though, so we can't really assert.
215    return;
216  }
217
218  // Otherwise, do a final copy,
219  assert(Dest.getAddr() != Src.getAggregateAddr());
220  EmitFinalDestCopy(E, Src, /*Ignore*/ true);
221}
222
223/// EmitFinalDestCopy - Perform the final copy to DestPtr, if desired.
224void AggExprEmitter::EmitFinalDestCopy(const Expr *E, RValue Src, bool Ignore) {
225  assert(Src.isAggregate() && "value must be aggregate value!");
226
227  // If Dest is ignored, then we're evaluating an aggregate expression
228  // in a context (like an expression statement) that doesn't care
229  // about the result.  C says that an lvalue-to-rvalue conversion is
230  // performed in these cases; C++ says that it is not.  In either
231  // case, we don't actually need to do anything unless the value is
232  // volatile.
233  if (Dest.isIgnored()) {
234    if (!Src.isVolatileQualified() ||
235        CGF.CGM.getLangOptions().CPlusPlus ||
236        (IgnoreResult && Ignore))
237      return;
238
239    // If the source is volatile, we must read from it; to do that, we need
240    // some place to put it.
241    Dest = CGF.CreateAggTemp(E->getType(), "agg.tmp");
242  }
243
244  if (Dest.requiresGCollection()) {
245    CharUnits size = CGF.getContext().getTypeSizeInChars(E->getType());
246    llvm::Type *SizeTy = CGF.ConvertType(CGF.getContext().getSizeType());
247    llvm::Value *SizeVal = llvm::ConstantInt::get(SizeTy, size.getQuantity());
248    CGF.CGM.getObjCRuntime().EmitGCMemmoveCollectable(CGF,
249                                                      Dest.getAddr(),
250                                                      Src.getAggregateAddr(),
251                                                      SizeVal);
252    return;
253  }
254  // If the result of the assignment is used, copy the LHS there also.
255  // FIXME: Pass VolatileDest as well.  I think we also need to merge volatile
256  // from the source as well, as we can't eliminate it if either operand
257  // is volatile, unless copy has volatile for both source and destination..
258  CGF.EmitAggregateCopy(Dest.getAddr(), Src.getAggregateAddr(), E->getType(),
259                        Dest.isVolatile()|Src.isVolatileQualified());
260}
261
262/// EmitFinalDestCopy - Perform the final copy to DestPtr, if desired.
263void AggExprEmitter::EmitFinalDestCopy(const Expr *E, LValue Src, bool Ignore) {
264  assert(Src.isSimple() && "Can't have aggregate bitfield, vector, etc");
265
266  EmitFinalDestCopy(E, RValue::getAggregate(Src.getAddress(),
267                                            Src.isVolatileQualified()),
268                    Ignore);
269}
270
271//===----------------------------------------------------------------------===//
272//                            Visitor Methods
273//===----------------------------------------------------------------------===//
274
275void AggExprEmitter::VisitMaterializeTemporaryExpr(MaterializeTemporaryExpr *E){
276  Visit(E->GetTemporaryExpr());
277}
278
279void AggExprEmitter::VisitOpaqueValueExpr(OpaqueValueExpr *e) {
280  EmitFinalDestCopy(e, CGF.getOpaqueLValueMapping(e));
281}
282
283void
284AggExprEmitter::VisitCompoundLiteralExpr(CompoundLiteralExpr *E) {
285  if (E->getType().isPODType(CGF.getContext())) {
286    // For a POD type, just emit a load of the lvalue + a copy, because our
287    // compound literal might alias the destination.
288    // FIXME: This is a band-aid; the real problem appears to be in our handling
289    // of assignments, where we store directly into the LHS without checking
290    // whether anything in the RHS aliases.
291    EmitAggLoadOfLValue(E);
292    return;
293  }
294
295  AggValueSlot Slot = EnsureSlot(E->getType());
296  CGF.EmitAggExpr(E->getInitializer(), Slot);
297}
298
299
300void AggExprEmitter::VisitCastExpr(CastExpr *E) {
301  switch (E->getCastKind()) {
302  case CK_Dynamic: {
303    assert(isa<CXXDynamicCastExpr>(E) && "CK_Dynamic without a dynamic_cast?");
304    LValue LV = CGF.EmitCheckedLValue(E->getSubExpr());
305    // FIXME: Do we also need to handle property references here?
306    if (LV.isSimple())
307      CGF.EmitDynamicCast(LV.getAddress(), cast<CXXDynamicCastExpr>(E));
308    else
309      CGF.CGM.ErrorUnsupported(E, "non-simple lvalue dynamic_cast");
310
311    if (!Dest.isIgnored())
312      CGF.CGM.ErrorUnsupported(E, "lvalue dynamic_cast with a destination");
313    break;
314  }
315
316  case CK_ToUnion: {
317    if (Dest.isIgnored()) break;
318
319    // GCC union extension
320    QualType Ty = E->getSubExpr()->getType();
321    QualType PtrTy = CGF.getContext().getPointerType(Ty);
322    llvm::Value *CastPtr = Builder.CreateBitCast(Dest.getAddr(),
323                                                 CGF.ConvertType(PtrTy));
324    EmitInitializationToLValue(E->getSubExpr(),
325                               CGF.MakeAddrLValue(CastPtr, Ty));
326    break;
327  }
328
329  case CK_DerivedToBase:
330  case CK_BaseToDerived:
331  case CK_UncheckedDerivedToBase: {
332    llvm_unreachable("cannot perform hierarchy conversion in EmitAggExpr: "
333                "should have been unpacked before we got here");
334  }
335
336  case CK_GetObjCProperty: llvm_unreachable("GetObjCProperty!");
337
338  case CK_LValueToRValue: // hope for downstream optimization
339  case CK_NoOp:
340  case CK_UserDefinedConversion:
341  case CK_ConstructorConversion:
342    assert(CGF.getContext().hasSameUnqualifiedType(E->getSubExpr()->getType(),
343                                                   E->getType()) &&
344           "Implicit cast types must be compatible");
345    Visit(E->getSubExpr());
346    break;
347
348  case CK_LValueBitCast:
349    llvm_unreachable("should not be emitting lvalue bitcast as rvalue");
350    break;
351
352  case CK_Dependent:
353  case CK_BitCast:
354  case CK_ArrayToPointerDecay:
355  case CK_FunctionToPointerDecay:
356  case CK_NullToPointer:
357  case CK_NullToMemberPointer:
358  case CK_BaseToDerivedMemberPointer:
359  case CK_DerivedToBaseMemberPointer:
360  case CK_MemberPointerToBoolean:
361  case CK_IntegralToPointer:
362  case CK_PointerToIntegral:
363  case CK_PointerToBoolean:
364  case CK_ToVoid:
365  case CK_VectorSplat:
366  case CK_IntegralCast:
367  case CK_IntegralToBoolean:
368  case CK_IntegralToFloating:
369  case CK_FloatingToIntegral:
370  case CK_FloatingToBoolean:
371  case CK_FloatingCast:
372  case CK_CPointerToObjCPointerCast:
373  case CK_BlockPointerToObjCPointerCast:
374  case CK_AnyPointerToBlockPointerCast:
375  case CK_ObjCObjectLValueCast:
376  case CK_FloatingRealToComplex:
377  case CK_FloatingComplexToReal:
378  case CK_FloatingComplexToBoolean:
379  case CK_FloatingComplexCast:
380  case CK_FloatingComplexToIntegralComplex:
381  case CK_IntegralRealToComplex:
382  case CK_IntegralComplexToReal:
383  case CK_IntegralComplexToBoolean:
384  case CK_IntegralComplexCast:
385  case CK_IntegralComplexToFloatingComplex:
386  case CK_ARCProduceObject:
387  case CK_ARCConsumeObject:
388  case CK_ARCReclaimReturnedObject:
389  case CK_ARCExtendBlockObject:
390    llvm_unreachable("cast kind invalid for aggregate types");
391  }
392}
393
394void AggExprEmitter::VisitCallExpr(const CallExpr *E) {
395  if (E->getCallReturnType()->isReferenceType()) {
396    EmitAggLoadOfLValue(E);
397    return;
398  }
399
400  RValue RV = CGF.EmitCallExpr(E, getReturnValueSlot());
401  EmitMoveFromReturnSlot(E, RV);
402}
403
404void AggExprEmitter::VisitObjCMessageExpr(ObjCMessageExpr *E) {
405  RValue RV = CGF.EmitObjCMessageExpr(E, getReturnValueSlot());
406  EmitMoveFromReturnSlot(E, RV);
407}
408
409void AggExprEmitter::VisitBinComma(const BinaryOperator *E) {
410  CGF.EmitIgnoredExpr(E->getLHS());
411  Visit(E->getRHS());
412}
413
414void AggExprEmitter::VisitStmtExpr(const StmtExpr *E) {
415  CodeGenFunction::StmtExprEvaluation eval(CGF);
416  CGF.EmitCompoundStmt(*E->getSubStmt(), true, Dest);
417}
418
419void AggExprEmitter::VisitBinaryOperator(const BinaryOperator *E) {
420  if (E->getOpcode() == BO_PtrMemD || E->getOpcode() == BO_PtrMemI)
421    VisitPointerToDataMemberBinaryOperator(E);
422  else
423    CGF.ErrorUnsupported(E, "aggregate binary expression");
424}
425
426void AggExprEmitter::VisitPointerToDataMemberBinaryOperator(
427                                                    const BinaryOperator *E) {
428  LValue LV = CGF.EmitPointerToDataMemberBinaryExpr(E);
429  EmitFinalDestCopy(E, LV);
430}
431
432void AggExprEmitter::VisitBinAssign(const BinaryOperator *E) {
433  // For an assignment to work, the value on the right has
434  // to be compatible with the value on the left.
435  assert(CGF.getContext().hasSameUnqualifiedType(E->getLHS()->getType(),
436                                                 E->getRHS()->getType())
437         && "Invalid assignment");
438
439  if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E->getLHS()))
440    if (const VarDecl *VD = dyn_cast<VarDecl>(DRE->getDecl()))
441      if (VD->hasAttr<BlocksAttr>() &&
442          E->getRHS()->HasSideEffects(CGF.getContext())) {
443        // When __block variable on LHS, the RHS must be evaluated first
444        // as it may change the 'forwarding' field via call to Block_copy.
445        LValue RHS = CGF.EmitLValue(E->getRHS());
446        LValue LHS = CGF.EmitLValue(E->getLHS());
447        Dest = AggValueSlot::forLValue(LHS, AggValueSlot::IsDestructed,
448                                       needsGC(E->getLHS()->getType()),
449                                       AggValueSlot::IsAliased);
450        EmitFinalDestCopy(E, RHS, true);
451        return;
452      }
453
454  LValue LHS = CGF.EmitLValue(E->getLHS());
455
456  // Codegen the RHS so that it stores directly into the LHS.
457  AggValueSlot LHSSlot =
458    AggValueSlot::forLValue(LHS, AggValueSlot::IsDestructed,
459                            needsGC(E->getLHS()->getType()),
460                            AggValueSlot::IsAliased);
461  CGF.EmitAggExpr(E->getRHS(), LHSSlot, false);
462  EmitFinalDestCopy(E, LHS, true);
463}
464
465void AggExprEmitter::
466VisitAbstractConditionalOperator(const AbstractConditionalOperator *E) {
467  llvm::BasicBlock *LHSBlock = CGF.createBasicBlock("cond.true");
468  llvm::BasicBlock *RHSBlock = CGF.createBasicBlock("cond.false");
469  llvm::BasicBlock *ContBlock = CGF.createBasicBlock("cond.end");
470
471  // Bind the common expression if necessary.
472  CodeGenFunction::OpaqueValueMapping binding(CGF, E);
473
474  CodeGenFunction::ConditionalEvaluation eval(CGF);
475  CGF.EmitBranchOnBoolExpr(E->getCond(), LHSBlock, RHSBlock);
476
477  // Save whether the destination's lifetime is externally managed.
478  bool isExternallyDestructed = Dest.isExternallyDestructed();
479
480  eval.begin(CGF);
481  CGF.EmitBlock(LHSBlock);
482  Visit(E->getTrueExpr());
483  eval.end(CGF);
484
485  assert(CGF.HaveInsertPoint() && "expression evaluation ended with no IP!");
486  CGF.Builder.CreateBr(ContBlock);
487
488  // If the result of an agg expression is unused, then the emission
489  // of the LHS might need to create a destination slot.  That's fine
490  // with us, and we can safely emit the RHS into the same slot, but
491  // we shouldn't claim that it's already being destructed.
492  Dest.setExternallyDestructed(isExternallyDestructed);
493
494  eval.begin(CGF);
495  CGF.EmitBlock(RHSBlock);
496  Visit(E->getFalseExpr());
497  eval.end(CGF);
498
499  CGF.EmitBlock(ContBlock);
500}
501
502void AggExprEmitter::VisitChooseExpr(const ChooseExpr *CE) {
503  Visit(CE->getChosenSubExpr(CGF.getContext()));
504}
505
506void AggExprEmitter::VisitVAArgExpr(VAArgExpr *VE) {
507  llvm::Value *ArgValue = CGF.EmitVAListRef(VE->getSubExpr());
508  llvm::Value *ArgPtr = CGF.EmitVAArg(ArgValue, VE->getType());
509
510  if (!ArgPtr) {
511    CGF.ErrorUnsupported(VE, "aggregate va_arg expression");
512    return;
513  }
514
515  EmitFinalDestCopy(VE, CGF.MakeAddrLValue(ArgPtr, VE->getType()));
516}
517
518void AggExprEmitter::VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E) {
519  // Ensure that we have a slot, but if we already do, remember
520  // whether it was externally destructed.
521  bool wasExternallyDestructed = Dest.isExternallyDestructed();
522  Dest = EnsureSlot(E->getType());
523
524  // We're going to push a destructor if there isn't already one.
525  Dest.setExternallyDestructed();
526
527  Visit(E->getSubExpr());
528
529  // Push that destructor we promised.
530  if (!wasExternallyDestructed)
531    CGF.EmitCXXTemporary(E->getTemporary(), Dest.getAddr());
532}
533
534void
535AggExprEmitter::VisitCXXConstructExpr(const CXXConstructExpr *E) {
536  AggValueSlot Slot = EnsureSlot(E->getType());
537  CGF.EmitCXXConstructExpr(E, Slot);
538}
539
540void AggExprEmitter::VisitExprWithCleanups(ExprWithCleanups *E) {
541  CGF.EmitExprWithCleanups(E, Dest);
542}
543
544void AggExprEmitter::VisitCXXScalarValueInitExpr(CXXScalarValueInitExpr *E) {
545  QualType T = E->getType();
546  AggValueSlot Slot = EnsureSlot(T);
547  EmitNullInitializationToLValue(CGF.MakeAddrLValue(Slot.getAddr(), T));
548}
549
550void AggExprEmitter::VisitImplicitValueInitExpr(ImplicitValueInitExpr *E) {
551  QualType T = E->getType();
552  AggValueSlot Slot = EnsureSlot(T);
553  EmitNullInitializationToLValue(CGF.MakeAddrLValue(Slot.getAddr(), T));
554}
555
556/// isSimpleZero - If emitting this value will obviously just cause a store of
557/// zero to memory, return true.  This can return false if uncertain, so it just
558/// handles simple cases.
559static bool isSimpleZero(const Expr *E, CodeGenFunction &CGF) {
560  E = E->IgnoreParens();
561
562  // 0
563  if (const IntegerLiteral *IL = dyn_cast<IntegerLiteral>(E))
564    return IL->getValue() == 0;
565  // +0.0
566  if (const FloatingLiteral *FL = dyn_cast<FloatingLiteral>(E))
567    return FL->getValue().isPosZero();
568  // int()
569  if ((isa<ImplicitValueInitExpr>(E) || isa<CXXScalarValueInitExpr>(E)) &&
570      CGF.getTypes().isZeroInitializable(E->getType()))
571    return true;
572  // (int*)0 - Null pointer expressions.
573  if (const CastExpr *ICE = dyn_cast<CastExpr>(E))
574    return ICE->getCastKind() == CK_NullToPointer;
575  // '\0'
576  if (const CharacterLiteral *CL = dyn_cast<CharacterLiteral>(E))
577    return CL->getValue() == 0;
578
579  // Otherwise, hard case: conservatively return false.
580  return false;
581}
582
583
584void
585AggExprEmitter::EmitInitializationToLValue(Expr* E, LValue LV) {
586  QualType type = LV.getType();
587  // FIXME: Ignore result?
588  // FIXME: Are initializers affected by volatile?
589  if (Dest.isZeroed() && isSimpleZero(E, CGF)) {
590    // Storing "i32 0" to a zero'd memory location is a noop.
591  } else if (isa<ImplicitValueInitExpr>(E)) {
592    EmitNullInitializationToLValue(LV);
593  } else if (type->isReferenceType()) {
594    RValue RV = CGF.EmitReferenceBindingToExpr(E, /*InitializedDecl=*/0);
595    CGF.EmitStoreThroughLValue(RV, LV);
596  } else if (type->isAnyComplexType()) {
597    CGF.EmitComplexExprIntoAddr(E, LV.getAddress(), false);
598  } else if (CGF.hasAggregateLLVMType(type)) {
599    CGF.EmitAggExpr(E, AggValueSlot::forLValue(LV,
600                                               AggValueSlot::IsDestructed,
601                                      AggValueSlot::DoesNotNeedGCBarriers,
602                                               AggValueSlot::IsNotAliased,
603                                               Dest.isZeroed()));
604  } else if (LV.isSimple()) {
605    CGF.EmitScalarInit(E, /*D=*/0, LV, /*Captured=*/false);
606  } else {
607    CGF.EmitStoreThroughLValue(RValue::get(CGF.EmitScalarExpr(E)), LV);
608  }
609}
610
611void AggExprEmitter::EmitNullInitializationToLValue(LValue lv) {
612  QualType type = lv.getType();
613
614  // If the destination slot is already zeroed out before the aggregate is
615  // copied into it, we don't have to emit any zeros here.
616  if (Dest.isZeroed() && CGF.getTypes().isZeroInitializable(type))
617    return;
618
619  if (!CGF.hasAggregateLLVMType(type)) {
620    // For non-aggregates, we can store zero
621    llvm::Value *null = llvm::Constant::getNullValue(CGF.ConvertType(type));
622    CGF.EmitStoreThroughLValue(RValue::get(null), lv);
623  } else {
624    // There's a potential optimization opportunity in combining
625    // memsets; that would be easy for arrays, but relatively
626    // difficult for structures with the current code.
627    CGF.EmitNullInitialization(lv.getAddress(), lv.getType());
628  }
629}
630
631void AggExprEmitter::VisitInitListExpr(InitListExpr *E) {
632#if 0
633  // FIXME: Assess perf here?  Figure out what cases are worth optimizing here
634  // (Length of globals? Chunks of zeroed-out space?).
635  //
636  // If we can, prefer a copy from a global; this is a lot less code for long
637  // globals, and it's easier for the current optimizers to analyze.
638  if (llvm::Constant* C = CGF.CGM.EmitConstantExpr(E, E->getType(), &CGF)) {
639    llvm::GlobalVariable* GV =
640    new llvm::GlobalVariable(CGF.CGM.getModule(), C->getType(), true,
641                             llvm::GlobalValue::InternalLinkage, C, "");
642    EmitFinalDestCopy(E, CGF.MakeAddrLValue(GV, E->getType()));
643    return;
644  }
645#endif
646  if (E->hadArrayRangeDesignator())
647    CGF.ErrorUnsupported(E, "GNU array range designator extension");
648
649  llvm::Value *DestPtr = Dest.getAddr();
650
651  // Handle initialization of an array.
652  if (E->getType()->isArrayType()) {
653    llvm::PointerType *APType =
654      cast<llvm::PointerType>(DestPtr->getType());
655    llvm::ArrayType *AType =
656      cast<llvm::ArrayType>(APType->getElementType());
657
658    uint64_t NumInitElements = E->getNumInits();
659
660    if (E->getNumInits() > 0) {
661      QualType T1 = E->getType();
662      QualType T2 = E->getInit(0)->getType();
663      if (CGF.getContext().hasSameUnqualifiedType(T1, T2)) {
664        EmitAggLoadOfLValue(E->getInit(0));
665        return;
666      }
667    }
668
669    uint64_t NumArrayElements = AType->getNumElements();
670    assert(NumInitElements <= NumArrayElements);
671
672    QualType elementType = E->getType().getCanonicalType();
673    elementType = CGF.getContext().getQualifiedType(
674                    cast<ArrayType>(elementType)->getElementType(),
675                    elementType.getQualifiers() + Dest.getQualifiers());
676
677    // DestPtr is an array*.  Construct an elementType* by drilling
678    // down a level.
679    llvm::Value *zero = llvm::ConstantInt::get(CGF.SizeTy, 0);
680    llvm::Value *indices[] = { zero, zero };
681    llvm::Value *begin =
682      Builder.CreateInBoundsGEP(DestPtr, indices, "arrayinit.begin");
683
684    // Exception safety requires us to destroy all the
685    // already-constructed members if an initializer throws.
686    // For that, we'll need an EH cleanup.
687    QualType::DestructionKind dtorKind = elementType.isDestructedType();
688    llvm::AllocaInst *endOfInit = 0;
689    EHScopeStack::stable_iterator cleanup;
690    if (CGF.needsEHCleanup(dtorKind)) {
691      // In principle we could tell the cleanup where we are more
692      // directly, but the control flow can get so varied here that it
693      // would actually be quite complex.  Therefore we go through an
694      // alloca.
695      endOfInit = CGF.CreateTempAlloca(begin->getType(),
696                                       "arrayinit.endOfInit");
697      Builder.CreateStore(begin, endOfInit);
698      CGF.pushIrregularPartialArrayCleanup(begin, endOfInit, elementType,
699                                           CGF.getDestroyer(dtorKind));
700      cleanup = CGF.EHStack.stable_begin();
701
702    // Otherwise, remember that we didn't need a cleanup.
703    } else {
704      dtorKind = QualType::DK_none;
705    }
706
707    llvm::Value *one = llvm::ConstantInt::get(CGF.SizeTy, 1);
708
709    // The 'current element to initialize'.  The invariants on this
710    // variable are complicated.  Essentially, after each iteration of
711    // the loop, it points to the last initialized element, except
712    // that it points to the beginning of the array before any
713    // elements have been initialized.
714    llvm::Value *element = begin;
715
716    // Emit the explicit initializers.
717    for (uint64_t i = 0; i != NumInitElements; ++i) {
718      // Advance to the next element.
719      if (i > 0) {
720        element = Builder.CreateInBoundsGEP(element, one, "arrayinit.element");
721
722        // Tell the cleanup that it needs to destroy up to this
723        // element.  TODO: some of these stores can be trivially
724        // observed to be unnecessary.
725        if (endOfInit) Builder.CreateStore(element, endOfInit);
726      }
727
728      LValue elementLV = CGF.MakeAddrLValue(element, elementType);
729      EmitInitializationToLValue(E->getInit(i), elementLV);
730    }
731
732    // Check whether there's a non-trivial array-fill expression.
733    // Note that this will be a CXXConstructExpr even if the element
734    // type is an array (or array of array, etc.) of class type.
735    Expr *filler = E->getArrayFiller();
736    bool hasTrivialFiller = true;
737    if (CXXConstructExpr *cons = dyn_cast_or_null<CXXConstructExpr>(filler)) {
738      assert(cons->getConstructor()->isDefaultConstructor());
739      hasTrivialFiller = cons->getConstructor()->isTrivial();
740    }
741
742    // Any remaining elements need to be zero-initialized, possibly
743    // using the filler expression.  We can skip this if the we're
744    // emitting to zeroed memory.
745    if (NumInitElements != NumArrayElements &&
746        !(Dest.isZeroed() && hasTrivialFiller &&
747          CGF.getTypes().isZeroInitializable(elementType))) {
748
749      // Use an actual loop.  This is basically
750      //   do { *array++ = filler; } while (array != end);
751
752      // Advance to the start of the rest of the array.
753      if (NumInitElements) {
754        element = Builder.CreateInBoundsGEP(element, one, "arrayinit.start");
755        if (endOfInit) Builder.CreateStore(element, endOfInit);
756      }
757
758      // Compute the end of the array.
759      llvm::Value *end = Builder.CreateInBoundsGEP(begin,
760                        llvm::ConstantInt::get(CGF.SizeTy, NumArrayElements),
761                                                   "arrayinit.end");
762
763      llvm::BasicBlock *entryBB = Builder.GetInsertBlock();
764      llvm::BasicBlock *bodyBB = CGF.createBasicBlock("arrayinit.body");
765
766      // Jump into the body.
767      CGF.EmitBlock(bodyBB);
768      llvm::PHINode *currentElement =
769        Builder.CreatePHI(element->getType(), 2, "arrayinit.cur");
770      currentElement->addIncoming(element, entryBB);
771
772      // Emit the actual filler expression.
773      LValue elementLV = CGF.MakeAddrLValue(currentElement, elementType);
774      if (filler)
775        EmitInitializationToLValue(filler, elementLV);
776      else
777        EmitNullInitializationToLValue(elementLV);
778
779      // Move on to the next element.
780      llvm::Value *nextElement =
781        Builder.CreateInBoundsGEP(currentElement, one, "arrayinit.next");
782
783      // Tell the EH cleanup that we finished with the last element.
784      if (endOfInit) Builder.CreateStore(nextElement, endOfInit);
785
786      // Leave the loop if we're done.
787      llvm::Value *done = Builder.CreateICmpEQ(nextElement, end,
788                                               "arrayinit.done");
789      llvm::BasicBlock *endBB = CGF.createBasicBlock("arrayinit.end");
790      Builder.CreateCondBr(done, endBB, bodyBB);
791      currentElement->addIncoming(nextElement, Builder.GetInsertBlock());
792
793      CGF.EmitBlock(endBB);
794    }
795
796    // Leave the partial-array cleanup if we entered one.
797    if (dtorKind) CGF.DeactivateCleanupBlock(cleanup);
798
799    return;
800  }
801
802  assert(E->getType()->isRecordType() && "Only support structs/unions here!");
803
804  // Do struct initialization; this code just sets each individual member
805  // to the approprate value.  This makes bitfield support automatic;
806  // the disadvantage is that the generated code is more difficult for
807  // the optimizer, especially with bitfields.
808  unsigned NumInitElements = E->getNumInits();
809  RecordDecl *record = E->getType()->castAs<RecordType>()->getDecl();
810
811  if (record->isUnion()) {
812    // Only initialize one field of a union. The field itself is
813    // specified by the initializer list.
814    if (!E->getInitializedFieldInUnion()) {
815      // Empty union; we have nothing to do.
816
817#ifndef NDEBUG
818      // Make sure that it's really an empty and not a failure of
819      // semantic analysis.
820      for (RecordDecl::field_iterator Field = record->field_begin(),
821                                   FieldEnd = record->field_end();
822           Field != FieldEnd; ++Field)
823        assert(Field->isUnnamedBitfield() && "Only unnamed bitfields allowed");
824#endif
825      return;
826    }
827
828    // FIXME: volatility
829    FieldDecl *Field = E->getInitializedFieldInUnion();
830
831    LValue FieldLoc = CGF.EmitLValueForFieldInitialization(DestPtr, Field, 0);
832    if (NumInitElements) {
833      // Store the initializer into the field
834      EmitInitializationToLValue(E->getInit(0), FieldLoc);
835    } else {
836      // Default-initialize to null.
837      EmitNullInitializationToLValue(FieldLoc);
838    }
839
840    return;
841  }
842
843  // We'll need to enter cleanup scopes in case any of the member
844  // initializers throw an exception.
845  SmallVector<EHScopeStack::stable_iterator, 16> cleanups;
846
847  // Here we iterate over the fields; this makes it simpler to both
848  // default-initialize fields and skip over unnamed fields.
849  unsigned curInitIndex = 0;
850  for (RecordDecl::field_iterator field = record->field_begin(),
851                               fieldEnd = record->field_end();
852       field != fieldEnd; ++field) {
853    // We're done once we hit the flexible array member.
854    if (field->getType()->isIncompleteArrayType())
855      break;
856
857    // Always skip anonymous bitfields.
858    if (field->isUnnamedBitfield())
859      continue;
860
861    // We're done if we reach the end of the explicit initializers, we
862    // have a zeroed object, and the rest of the fields are
863    // zero-initializable.
864    if (curInitIndex == NumInitElements && Dest.isZeroed() &&
865        CGF.getTypes().isZeroInitializable(E->getType()))
866      break;
867
868    // FIXME: volatility
869    LValue LV = CGF.EmitLValueForFieldInitialization(DestPtr, *field, 0);
870    // We never generate write-barries for initialized fields.
871    LV.setNonGC(true);
872
873    if (curInitIndex < NumInitElements) {
874      // Store the initializer into the field.
875      EmitInitializationToLValue(E->getInit(curInitIndex++), LV);
876    } else {
877      // We're out of initalizers; default-initialize to null
878      EmitNullInitializationToLValue(LV);
879    }
880
881    // Push a destructor if necessary.
882    // FIXME: if we have an array of structures, all explicitly
883    // initialized, we can end up pushing a linear number of cleanups.
884    bool pushedCleanup = false;
885    if (QualType::DestructionKind dtorKind
886          = field->getType().isDestructedType()) {
887      assert(LV.isSimple());
888      if (CGF.needsEHCleanup(dtorKind)) {
889        CGF.pushDestroy(EHCleanup, LV.getAddress(), field->getType(),
890                        CGF.getDestroyer(dtorKind), false);
891        cleanups.push_back(CGF.EHStack.stable_begin());
892        pushedCleanup = true;
893      }
894    }
895
896    // If the GEP didn't get used because of a dead zero init or something
897    // else, clean it up for -O0 builds and general tidiness.
898    if (!pushedCleanup && LV.isSimple())
899      if (llvm::GetElementPtrInst *GEP =
900            dyn_cast<llvm::GetElementPtrInst>(LV.getAddress()))
901        if (GEP->use_empty())
902          GEP->eraseFromParent();
903  }
904
905  // Deactivate all the partial cleanups in reverse order, which
906  // generally means popping them.
907  for (unsigned i = cleanups.size(); i != 0; --i)
908    CGF.DeactivateCleanupBlock(cleanups[i-1]);
909}
910
911//===----------------------------------------------------------------------===//
912//                        Entry Points into this File
913//===----------------------------------------------------------------------===//
914
915/// GetNumNonZeroBytesInInit - Get an approximate count of the number of
916/// non-zero bytes that will be stored when outputting the initializer for the
917/// specified initializer expression.
918static CharUnits GetNumNonZeroBytesInInit(const Expr *E, CodeGenFunction &CGF) {
919  E = E->IgnoreParens();
920
921  // 0 and 0.0 won't require any non-zero stores!
922  if (isSimpleZero(E, CGF)) return CharUnits::Zero();
923
924  // If this is an initlist expr, sum up the size of sizes of the (present)
925  // elements.  If this is something weird, assume the whole thing is non-zero.
926  const InitListExpr *ILE = dyn_cast<InitListExpr>(E);
927  if (ILE == 0 || !CGF.getTypes().isZeroInitializable(ILE->getType()))
928    return CGF.getContext().getTypeSizeInChars(E->getType());
929
930  // InitListExprs for structs have to be handled carefully.  If there are
931  // reference members, we need to consider the size of the reference, not the
932  // referencee.  InitListExprs for unions and arrays can't have references.
933  if (const RecordType *RT = E->getType()->getAs<RecordType>()) {
934    if (!RT->isUnionType()) {
935      RecordDecl *SD = E->getType()->getAs<RecordType>()->getDecl();
936      CharUnits NumNonZeroBytes = CharUnits::Zero();
937
938      unsigned ILEElement = 0;
939      for (RecordDecl::field_iterator Field = SD->field_begin(),
940           FieldEnd = SD->field_end(); Field != FieldEnd; ++Field) {
941        // We're done once we hit the flexible array member or run out of
942        // InitListExpr elements.
943        if (Field->getType()->isIncompleteArrayType() ||
944            ILEElement == ILE->getNumInits())
945          break;
946        if (Field->isUnnamedBitfield())
947          continue;
948
949        const Expr *E = ILE->getInit(ILEElement++);
950
951        // Reference values are always non-null and have the width of a pointer.
952        if (Field->getType()->isReferenceType())
953          NumNonZeroBytes += CGF.getContext().toCharUnitsFromBits(
954              CGF.getContext().getTargetInfo().getPointerWidth(0));
955        else
956          NumNonZeroBytes += GetNumNonZeroBytesInInit(E, CGF);
957      }
958
959      return NumNonZeroBytes;
960    }
961  }
962
963
964  CharUnits NumNonZeroBytes = CharUnits::Zero();
965  for (unsigned i = 0, e = ILE->getNumInits(); i != e; ++i)
966    NumNonZeroBytes += GetNumNonZeroBytesInInit(ILE->getInit(i), CGF);
967  return NumNonZeroBytes;
968}
969
970/// CheckAggExprForMemSetUse - If the initializer is large and has a lot of
971/// zeros in it, emit a memset and avoid storing the individual zeros.
972///
973static void CheckAggExprForMemSetUse(AggValueSlot &Slot, const Expr *E,
974                                     CodeGenFunction &CGF) {
975  // If the slot is already known to be zeroed, nothing to do.  Don't mess with
976  // volatile stores.
977  if (Slot.isZeroed() || Slot.isVolatile() || Slot.getAddr() == 0) return;
978
979  // C++ objects with a user-declared constructor don't need zero'ing.
980  if (CGF.getContext().getLangOptions().CPlusPlus)
981    if (const RecordType *RT = CGF.getContext()
982                       .getBaseElementType(E->getType())->getAs<RecordType>()) {
983      const CXXRecordDecl *RD = cast<CXXRecordDecl>(RT->getDecl());
984      if (RD->hasUserDeclaredConstructor())
985        return;
986    }
987
988  // If the type is 16-bytes or smaller, prefer individual stores over memset.
989  std::pair<CharUnits, CharUnits> TypeInfo =
990    CGF.getContext().getTypeInfoInChars(E->getType());
991  if (TypeInfo.first <= CharUnits::fromQuantity(16))
992    return;
993
994  // Check to see if over 3/4 of the initializer are known to be zero.  If so,
995  // we prefer to emit memset + individual stores for the rest.
996  CharUnits NumNonZeroBytes = GetNumNonZeroBytesInInit(E, CGF);
997  if (NumNonZeroBytes*4 > TypeInfo.first)
998    return;
999
1000  // Okay, it seems like a good idea to use an initial memset, emit the call.
1001  llvm::Constant *SizeVal = CGF.Builder.getInt64(TypeInfo.first.getQuantity());
1002  CharUnits Align = TypeInfo.second;
1003
1004  llvm::Value *Loc = Slot.getAddr();
1005  llvm::Type *BP = llvm::Type::getInt8PtrTy(CGF.getLLVMContext());
1006
1007  Loc = CGF.Builder.CreateBitCast(Loc, BP);
1008  CGF.Builder.CreateMemSet(Loc, CGF.Builder.getInt8(0), SizeVal,
1009                           Align.getQuantity(), false);
1010
1011  // Tell the AggExprEmitter that the slot is known zero.
1012  Slot.setZeroed();
1013}
1014
1015
1016
1017
1018/// EmitAggExpr - Emit the computation of the specified expression of aggregate
1019/// type.  The result is computed into DestPtr.  Note that if DestPtr is null,
1020/// the value of the aggregate expression is not needed.  If VolatileDest is
1021/// true, DestPtr cannot be 0.
1022///
1023/// \param IsInitializer - true if this evaluation is initializing an
1024/// object whose lifetime is already being managed.
1025void CodeGenFunction::EmitAggExpr(const Expr *E, AggValueSlot Slot,
1026                                  bool IgnoreResult) {
1027  assert(E && hasAggregateLLVMType(E->getType()) &&
1028         "Invalid aggregate expression to emit");
1029  assert((Slot.getAddr() != 0 || Slot.isIgnored()) &&
1030         "slot has bits but no address");
1031
1032  // Optimize the slot if possible.
1033  CheckAggExprForMemSetUse(Slot, E, *this);
1034
1035  AggExprEmitter(*this, Slot, IgnoreResult).Visit(const_cast<Expr*>(E));
1036}
1037
1038LValue CodeGenFunction::EmitAggExprToLValue(const Expr *E) {
1039  assert(hasAggregateLLVMType(E->getType()) && "Invalid argument!");
1040  llvm::Value *Temp = CreateMemTemp(E->getType());
1041  LValue LV = MakeAddrLValue(Temp, E->getType());
1042  EmitAggExpr(E, AggValueSlot::forLValue(LV, AggValueSlot::IsNotDestructed,
1043                                         AggValueSlot::DoesNotNeedGCBarriers,
1044                                         AggValueSlot::IsNotAliased));
1045  return LV;
1046}
1047
1048void CodeGenFunction::EmitAggregateCopy(llvm::Value *DestPtr,
1049                                        llvm::Value *SrcPtr, QualType Ty,
1050                                        bool isVolatile) {
1051  assert(!Ty->isAnyComplexType() && "Shouldn't happen for complex");
1052
1053  if (getContext().getLangOptions().CPlusPlus) {
1054    if (const RecordType *RT = Ty->getAs<RecordType>()) {
1055      CXXRecordDecl *Record = cast<CXXRecordDecl>(RT->getDecl());
1056      assert((Record->hasTrivialCopyConstructor() ||
1057              Record->hasTrivialCopyAssignment() ||
1058              Record->hasTrivialMoveConstructor() ||
1059              Record->hasTrivialMoveAssignment()) &&
1060             "Trying to aggregate-copy a type without a trivial copy "
1061             "constructor or assignment operator");
1062      // Ignore empty classes in C++.
1063      if (Record->isEmpty())
1064        return;
1065    }
1066  }
1067
1068  // Aggregate assignment turns into llvm.memcpy.  This is almost valid per
1069  // C99 6.5.16.1p3, which states "If the value being stored in an object is
1070  // read from another object that overlaps in anyway the storage of the first
1071  // object, then the overlap shall be exact and the two objects shall have
1072  // qualified or unqualified versions of a compatible type."
1073  //
1074  // memcpy is not defined if the source and destination pointers are exactly
1075  // equal, but other compilers do this optimization, and almost every memcpy
1076  // implementation handles this case safely.  If there is a libc that does not
1077  // safely handle this, we can add a target hook.
1078
1079  // Get size and alignment info for this aggregate.
1080  std::pair<CharUnits, CharUnits> TypeInfo =
1081    getContext().getTypeInfoInChars(Ty);
1082
1083  // FIXME: Handle variable sized types.
1084
1085  // FIXME: If we have a volatile struct, the optimizer can remove what might
1086  // appear to be `extra' memory ops:
1087  //
1088  // volatile struct { int i; } a, b;
1089  //
1090  // int main() {
1091  //   a = b;
1092  //   a = b;
1093  // }
1094  //
1095  // we need to use a different call here.  We use isVolatile to indicate when
1096  // either the source or the destination is volatile.
1097
1098  llvm::PointerType *DPT = cast<llvm::PointerType>(DestPtr->getType());
1099  llvm::Type *DBP =
1100    llvm::Type::getInt8PtrTy(getLLVMContext(), DPT->getAddressSpace());
1101  DestPtr = Builder.CreateBitCast(DestPtr, DBP);
1102
1103  llvm::PointerType *SPT = cast<llvm::PointerType>(SrcPtr->getType());
1104  llvm::Type *SBP =
1105    llvm::Type::getInt8PtrTy(getLLVMContext(), SPT->getAddressSpace());
1106  SrcPtr = Builder.CreateBitCast(SrcPtr, SBP);
1107
1108  // Don't do any of the memmove_collectable tests if GC isn't set.
1109  if (CGM.getLangOptions().getGC() == LangOptions::NonGC) {
1110    // fall through
1111  } else if (const RecordType *RecordTy = Ty->getAs<RecordType>()) {
1112    RecordDecl *Record = RecordTy->getDecl();
1113    if (Record->hasObjectMember()) {
1114      CharUnits size = TypeInfo.first;
1115      llvm::Type *SizeTy = ConvertType(getContext().getSizeType());
1116      llvm::Value *SizeVal = llvm::ConstantInt::get(SizeTy, size.getQuantity());
1117      CGM.getObjCRuntime().EmitGCMemmoveCollectable(*this, DestPtr, SrcPtr,
1118                                                    SizeVal);
1119      return;
1120    }
1121  } else if (Ty->isArrayType()) {
1122    QualType BaseType = getContext().getBaseElementType(Ty);
1123    if (const RecordType *RecordTy = BaseType->getAs<RecordType>()) {
1124      if (RecordTy->getDecl()->hasObjectMember()) {
1125        CharUnits size = TypeInfo.first;
1126        llvm::Type *SizeTy = ConvertType(getContext().getSizeType());
1127        llvm::Value *SizeVal =
1128          llvm::ConstantInt::get(SizeTy, size.getQuantity());
1129        CGM.getObjCRuntime().EmitGCMemmoveCollectable(*this, DestPtr, SrcPtr,
1130                                                      SizeVal);
1131        return;
1132      }
1133    }
1134  }
1135
1136  Builder.CreateMemCpy(DestPtr, SrcPtr,
1137                       llvm::ConstantInt::get(IntPtrTy,
1138                                              TypeInfo.first.getQuantity()),
1139                       TypeInfo.second.getQuantity(), isVolatile);
1140}
1141