CGExprAgg.cpp revision 7864435ef2bce200224120bd1df3aed98ea5b99a 
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_LValueToRValue: // hope for downstream optimization
337  case CK_NoOp:
338  case CK_UserDefinedConversion:
339  case CK_ConstructorConversion:
340    assert(CGF.getContext().hasSameUnqualifiedType(E->getSubExpr()->getType(),
341                                                   E->getType()) &&
342           "Implicit cast types must be compatible");
343    Visit(E->getSubExpr());
344    break;
345
346  case CK_LValueBitCast:
347    llvm_unreachable("should not be emitting lvalue bitcast as rvalue");
348    break;
349
350  case CK_Dependent:
351  case CK_BitCast:
352  case CK_ArrayToPointerDecay:
353  case CK_FunctionToPointerDecay:
354  case CK_NullToPointer:
355  case CK_NullToMemberPointer:
356  case CK_BaseToDerivedMemberPointer:
357  case CK_DerivedToBaseMemberPointer:
358  case CK_MemberPointerToBoolean:
359  case CK_IntegralToPointer:
360  case CK_PointerToIntegral:
361  case CK_PointerToBoolean:
362  case CK_ToVoid:
363  case CK_VectorSplat:
364  case CK_IntegralCast:
365  case CK_IntegralToBoolean:
366  case CK_IntegralToFloating:
367  case CK_FloatingToIntegral:
368  case CK_FloatingToBoolean:
369  case CK_FloatingCast:
370  case CK_CPointerToObjCPointerCast:
371  case CK_BlockPointerToObjCPointerCast:
372  case CK_AnyPointerToBlockPointerCast:
373  case CK_ObjCObjectLValueCast:
374  case CK_FloatingRealToComplex:
375  case CK_FloatingComplexToReal:
376  case CK_FloatingComplexToBoolean:
377  case CK_FloatingComplexCast:
378  case CK_FloatingComplexToIntegralComplex:
379  case CK_IntegralRealToComplex:
380  case CK_IntegralComplexToReal:
381  case CK_IntegralComplexToBoolean:
382  case CK_IntegralComplexCast:
383  case CK_IntegralComplexToFloatingComplex:
384  case CK_ARCProduceObject:
385  case CK_ARCConsumeObject:
386  case CK_ARCReclaimReturnedObject:
387  case CK_ARCExtendBlockObject:
388    llvm_unreachable("cast kind invalid for aggregate types");
389  }
390}
391
392void AggExprEmitter::VisitCallExpr(const CallExpr *E) {
393  if (E->getCallReturnType()->isReferenceType()) {
394    EmitAggLoadOfLValue(E);
395    return;
396  }
397
398  RValue RV = CGF.EmitCallExpr(E, getReturnValueSlot());
399  EmitMoveFromReturnSlot(E, RV);
400}
401
402void AggExprEmitter::VisitObjCMessageExpr(ObjCMessageExpr *E) {
403  RValue RV = CGF.EmitObjCMessageExpr(E, getReturnValueSlot());
404  EmitMoveFromReturnSlot(E, RV);
405}
406
407void AggExprEmitter::VisitBinComma(const BinaryOperator *E) {
408  CGF.EmitIgnoredExpr(E->getLHS());
409  Visit(E->getRHS());
410}
411
412void AggExprEmitter::VisitStmtExpr(const StmtExpr *E) {
413  CodeGenFunction::StmtExprEvaluation eval(CGF);
414  CGF.EmitCompoundStmt(*E->getSubStmt(), true, Dest);
415}
416
417void AggExprEmitter::VisitBinaryOperator(const BinaryOperator *E) {
418  if (E->getOpcode() == BO_PtrMemD || E->getOpcode() == BO_PtrMemI)
419    VisitPointerToDataMemberBinaryOperator(E);
420  else
421    CGF.ErrorUnsupported(E, "aggregate binary expression");
422}
423
424void AggExprEmitter::VisitPointerToDataMemberBinaryOperator(
425                                                    const BinaryOperator *E) {
426  LValue LV = CGF.EmitPointerToDataMemberBinaryExpr(E);
427  EmitFinalDestCopy(E, LV);
428}
429
430void AggExprEmitter::VisitBinAssign(const BinaryOperator *E) {
431  // For an assignment to work, the value on the right has
432  // to be compatible with the value on the left.
433  assert(CGF.getContext().hasSameUnqualifiedType(E->getLHS()->getType(),
434                                                 E->getRHS()->getType())
435         && "Invalid assignment");
436
437  if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E->getLHS()))
438    if (const VarDecl *VD = dyn_cast<VarDecl>(DRE->getDecl()))
439      if (VD->hasAttr<BlocksAttr>() &&
440          E->getRHS()->HasSideEffects(CGF.getContext())) {
441        // When __block variable on LHS, the RHS must be evaluated first
442        // as it may change the 'forwarding' field via call to Block_copy.
443        LValue RHS = CGF.EmitLValue(E->getRHS());
444        LValue LHS = CGF.EmitLValue(E->getLHS());
445        Dest = AggValueSlot::forLValue(LHS, AggValueSlot::IsDestructed,
446                                       needsGC(E->getLHS()->getType()),
447                                       AggValueSlot::IsAliased);
448        EmitFinalDestCopy(E, RHS, true);
449        return;
450      }
451
452  LValue LHS = CGF.EmitLValue(E->getLHS());
453
454  // Codegen the RHS so that it stores directly into the LHS.
455  AggValueSlot LHSSlot =
456    AggValueSlot::forLValue(LHS, AggValueSlot::IsDestructed,
457                            needsGC(E->getLHS()->getType()),
458                            AggValueSlot::IsAliased);
459  CGF.EmitAggExpr(E->getRHS(), LHSSlot, false);
460  EmitFinalDestCopy(E, LHS, true);
461}
462
463void AggExprEmitter::
464VisitAbstractConditionalOperator(const AbstractConditionalOperator *E) {
465  llvm::BasicBlock *LHSBlock = CGF.createBasicBlock("cond.true");
466  llvm::BasicBlock *RHSBlock = CGF.createBasicBlock("cond.false");
467  llvm::BasicBlock *ContBlock = CGF.createBasicBlock("cond.end");
468
469  // Bind the common expression if necessary.
470  CodeGenFunction::OpaqueValueMapping binding(CGF, E);
471
472  CodeGenFunction::ConditionalEvaluation eval(CGF);
473  CGF.EmitBranchOnBoolExpr(E->getCond(), LHSBlock, RHSBlock);
474
475  // Save whether the destination's lifetime is externally managed.
476  bool isExternallyDestructed = Dest.isExternallyDestructed();
477
478  eval.begin(CGF);
479  CGF.EmitBlock(LHSBlock);
480  Visit(E->getTrueExpr());
481  eval.end(CGF);
482
483  assert(CGF.HaveInsertPoint() && "expression evaluation ended with no IP!");
484  CGF.Builder.CreateBr(ContBlock);
485
486  // If the result of an agg expression is unused, then the emission
487  // of the LHS might need to create a destination slot.  That's fine
488  // with us, and we can safely emit the RHS into the same slot, but
489  // we shouldn't claim that it's already being destructed.
490  Dest.setExternallyDestructed(isExternallyDestructed);
491
492  eval.begin(CGF);
493  CGF.EmitBlock(RHSBlock);
494  Visit(E->getFalseExpr());
495  eval.end(CGF);
496
497  CGF.EmitBlock(ContBlock);
498}
499
500void AggExprEmitter::VisitChooseExpr(const ChooseExpr *CE) {
501  Visit(CE->getChosenSubExpr(CGF.getContext()));
502}
503
504void AggExprEmitter::VisitVAArgExpr(VAArgExpr *VE) {
505  llvm::Value *ArgValue = CGF.EmitVAListRef(VE->getSubExpr());
506  llvm::Value *ArgPtr = CGF.EmitVAArg(ArgValue, VE->getType());
507
508  if (!ArgPtr) {
509    CGF.ErrorUnsupported(VE, "aggregate va_arg expression");
510    return;
511  }
512
513  EmitFinalDestCopy(VE, CGF.MakeAddrLValue(ArgPtr, VE->getType()));
514}
515
516void AggExprEmitter::VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E) {
517  // Ensure that we have a slot, but if we already do, remember
518  // whether it was externally destructed.
519  bool wasExternallyDestructed = Dest.isExternallyDestructed();
520  Dest = EnsureSlot(E->getType());
521
522  // We're going to push a destructor if there isn't already one.
523  Dest.setExternallyDestructed();
524
525  Visit(E->getSubExpr());
526
527  // Push that destructor we promised.
528  if (!wasExternallyDestructed)
529    CGF.EmitCXXTemporary(E->getTemporary(), Dest.getAddr());
530}
531
532void
533AggExprEmitter::VisitCXXConstructExpr(const CXXConstructExpr *E) {
534  AggValueSlot Slot = EnsureSlot(E->getType());
535  CGF.EmitCXXConstructExpr(E, Slot);
536}
537
538void AggExprEmitter::VisitExprWithCleanups(ExprWithCleanups *E) {
539  CGF.EmitExprWithCleanups(E, Dest);
540}
541
542void AggExprEmitter::VisitCXXScalarValueInitExpr(CXXScalarValueInitExpr *E) {
543  QualType T = E->getType();
544  AggValueSlot Slot = EnsureSlot(T);
545  EmitNullInitializationToLValue(CGF.MakeAddrLValue(Slot.getAddr(), T));
546}
547
548void AggExprEmitter::VisitImplicitValueInitExpr(ImplicitValueInitExpr *E) {
549  QualType T = E->getType();
550  AggValueSlot Slot = EnsureSlot(T);
551  EmitNullInitializationToLValue(CGF.MakeAddrLValue(Slot.getAddr(), T));
552}
553
554/// isSimpleZero - If emitting this value will obviously just cause a store of
555/// zero to memory, return true.  This can return false if uncertain, so it just
556/// handles simple cases.
557static bool isSimpleZero(const Expr *E, CodeGenFunction &CGF) {
558  E = E->IgnoreParens();
559
560  // 0
561  if (const IntegerLiteral *IL = dyn_cast<IntegerLiteral>(E))
562    return IL->getValue() == 0;
563  // +0.0
564  if (const FloatingLiteral *FL = dyn_cast<FloatingLiteral>(E))
565    return FL->getValue().isPosZero();
566  // int()
567  if ((isa<ImplicitValueInitExpr>(E) || isa<CXXScalarValueInitExpr>(E)) &&
568      CGF.getTypes().isZeroInitializable(E->getType()))
569    return true;
570  // (int*)0 - Null pointer expressions.
571  if (const CastExpr *ICE = dyn_cast<CastExpr>(E))
572    return ICE->getCastKind() == CK_NullToPointer;
573  // '\0'
574  if (const CharacterLiteral *CL = dyn_cast<CharacterLiteral>(E))
575    return CL->getValue() == 0;
576
577  // Otherwise, hard case: conservatively return false.
578  return false;
579}
580
581
582void
583AggExprEmitter::EmitInitializationToLValue(Expr* E, LValue LV) {
584  QualType type = LV.getType();
585  // FIXME: Ignore result?
586  // FIXME: Are initializers affected by volatile?
587  if (Dest.isZeroed() && isSimpleZero(E, CGF)) {
588    // Storing "i32 0" to a zero'd memory location is a noop.
589  } else if (isa<ImplicitValueInitExpr>(E)) {
590    EmitNullInitializationToLValue(LV);
591  } else if (type->isReferenceType()) {
592    RValue RV = CGF.EmitReferenceBindingToExpr(E, /*InitializedDecl=*/0);
593    CGF.EmitStoreThroughLValue(RV, LV);
594  } else if (type->isAnyComplexType()) {
595    CGF.EmitComplexExprIntoAddr(E, LV.getAddress(), false);
596  } else if (CGF.hasAggregateLLVMType(type)) {
597    CGF.EmitAggExpr(E, AggValueSlot::forLValue(LV,
598                                               AggValueSlot::IsDestructed,
599                                      AggValueSlot::DoesNotNeedGCBarriers,
600                                               AggValueSlot::IsNotAliased,
601                                               Dest.isZeroed()));
602  } else if (LV.isSimple()) {
603    CGF.EmitScalarInit(E, /*D=*/0, LV, /*Captured=*/false);
604  } else {
605    CGF.EmitStoreThroughLValue(RValue::get(CGF.EmitScalarExpr(E)), LV);
606  }
607}
608
609void AggExprEmitter::EmitNullInitializationToLValue(LValue lv) {
610  QualType type = lv.getType();
611
612  // If the destination slot is already zeroed out before the aggregate is
613  // copied into it, we don't have to emit any zeros here.
614  if (Dest.isZeroed() && CGF.getTypes().isZeroInitializable(type))
615    return;
616
617  if (!CGF.hasAggregateLLVMType(type)) {
618    // For non-aggregates, we can store zero
619    llvm::Value *null = llvm::Constant::getNullValue(CGF.ConvertType(type));
620    CGF.EmitStoreThroughLValue(RValue::get(null), lv);
621  } else {
622    // There's a potential optimization opportunity in combining
623    // memsets; that would be easy for arrays, but relatively
624    // difficult for structures with the current code.
625    CGF.EmitNullInitialization(lv.getAddress(), lv.getType());
626  }
627}
628
629void AggExprEmitter::VisitInitListExpr(InitListExpr *E) {
630#if 0
631  // FIXME: Assess perf here?  Figure out what cases are worth optimizing here
632  // (Length of globals? Chunks of zeroed-out space?).
633  //
634  // If we can, prefer a copy from a global; this is a lot less code for long
635  // globals, and it's easier for the current optimizers to analyze.
636  if (llvm::Constant* C = CGF.CGM.EmitConstantExpr(E, E->getType(), &CGF)) {
637    llvm::GlobalVariable* GV =
638    new llvm::GlobalVariable(CGF.CGM.getModule(), C->getType(), true,
639                             llvm::GlobalValue::InternalLinkage, C, "");
640    EmitFinalDestCopy(E, CGF.MakeAddrLValue(GV, E->getType()));
641    return;
642  }
643#endif
644  if (E->hadArrayRangeDesignator())
645    CGF.ErrorUnsupported(E, "GNU array range designator extension");
646
647  llvm::Value *DestPtr = Dest.getAddr();
648
649  // Handle initialization of an array.
650  if (E->getType()->isArrayType()) {
651    llvm::PointerType *APType =
652      cast<llvm::PointerType>(DestPtr->getType());
653    llvm::ArrayType *AType =
654      cast<llvm::ArrayType>(APType->getElementType());
655
656    uint64_t NumInitElements = E->getNumInits();
657
658    if (E->getNumInits() > 0) {
659      QualType T1 = E->getType();
660      QualType T2 = E->getInit(0)->getType();
661      if (CGF.getContext().hasSameUnqualifiedType(T1, T2)) {
662        EmitAggLoadOfLValue(E->getInit(0));
663        return;
664      }
665    }
666
667    uint64_t NumArrayElements = AType->getNumElements();
668    assert(NumInitElements <= NumArrayElements);
669
670    QualType elementType = E->getType().getCanonicalType();
671    elementType = CGF.getContext().getQualifiedType(
672                    cast<ArrayType>(elementType)->getElementType(),
673                    elementType.getQualifiers() + Dest.getQualifiers());
674
675    // DestPtr is an array*.  Construct an elementType* by drilling
676    // down a level.
677    llvm::Value *zero = llvm::ConstantInt::get(CGF.SizeTy, 0);
678    llvm::Value *indices[] = { zero, zero };
679    llvm::Value *begin =
680      Builder.CreateInBoundsGEP(DestPtr, indices, "arrayinit.begin");
681
682    // Exception safety requires us to destroy all the
683    // already-constructed members if an initializer throws.
684    // For that, we'll need an EH cleanup.
685    QualType::DestructionKind dtorKind = elementType.isDestructedType();
686    llvm::AllocaInst *endOfInit = 0;
687    EHScopeStack::stable_iterator cleanup;
688    if (CGF.needsEHCleanup(dtorKind)) {
689      // In principle we could tell the cleanup where we are more
690      // directly, but the control flow can get so varied here that it
691      // would actually be quite complex.  Therefore we go through an
692      // alloca.
693      endOfInit = CGF.CreateTempAlloca(begin->getType(),
694                                       "arrayinit.endOfInit");
695      Builder.CreateStore(begin, endOfInit);
696      CGF.pushIrregularPartialArrayCleanup(begin, endOfInit, elementType,
697                                           CGF.getDestroyer(dtorKind));
698      cleanup = CGF.EHStack.stable_begin();
699
700    // Otherwise, remember that we didn't need a cleanup.
701    } else {
702      dtorKind = QualType::DK_none;
703    }
704
705    llvm::Value *one = llvm::ConstantInt::get(CGF.SizeTy, 1);
706
707    // The 'current element to initialize'.  The invariants on this
708    // variable are complicated.  Essentially, after each iteration of
709    // the loop, it points to the last initialized element, except
710    // that it points to the beginning of the array before any
711    // elements have been initialized.
712    llvm::Value *element = begin;
713
714    // Emit the explicit initializers.
715    for (uint64_t i = 0; i != NumInitElements; ++i) {
716      // Advance to the next element.
717      if (i > 0) {
718        element = Builder.CreateInBoundsGEP(element, one, "arrayinit.element");
719
720        // Tell the cleanup that it needs to destroy up to this
721        // element.  TODO: some of these stores can be trivially
722        // observed to be unnecessary.
723        if (endOfInit) Builder.CreateStore(element, endOfInit);
724      }
725
726      LValue elementLV = CGF.MakeAddrLValue(element, elementType);
727      EmitInitializationToLValue(E->getInit(i), elementLV);
728    }
729
730    // Check whether there's a non-trivial array-fill expression.
731    // Note that this will be a CXXConstructExpr even if the element
732    // type is an array (or array of array, etc.) of class type.
733    Expr *filler = E->getArrayFiller();
734    bool hasTrivialFiller = true;
735    if (CXXConstructExpr *cons = dyn_cast_or_null<CXXConstructExpr>(filler)) {
736      assert(cons->getConstructor()->isDefaultConstructor());
737      hasTrivialFiller = cons->getConstructor()->isTrivial();
738    }
739
740    // Any remaining elements need to be zero-initialized, possibly
741    // using the filler expression.  We can skip this if the we're
742    // emitting to zeroed memory.
743    if (NumInitElements != NumArrayElements &&
744        !(Dest.isZeroed() && hasTrivialFiller &&
745          CGF.getTypes().isZeroInitializable(elementType))) {
746
747      // Use an actual loop.  This is basically
748      //   do { *array++ = filler; } while (array != end);
749
750      // Advance to the start of the rest of the array.
751      if (NumInitElements) {
752        element = Builder.CreateInBoundsGEP(element, one, "arrayinit.start");
753        if (endOfInit) Builder.CreateStore(element, endOfInit);
754      }
755
756      // Compute the end of the array.
757      llvm::Value *end = Builder.CreateInBoundsGEP(begin,
758                        llvm::ConstantInt::get(CGF.SizeTy, NumArrayElements),
759                                                   "arrayinit.end");
760
761      llvm::BasicBlock *entryBB = Builder.GetInsertBlock();
762      llvm::BasicBlock *bodyBB = CGF.createBasicBlock("arrayinit.body");
763
764      // Jump into the body.
765      CGF.EmitBlock(bodyBB);
766      llvm::PHINode *currentElement =
767        Builder.CreatePHI(element->getType(), 2, "arrayinit.cur");
768      currentElement->addIncoming(element, entryBB);
769
770      // Emit the actual filler expression.
771      LValue elementLV = CGF.MakeAddrLValue(currentElement, elementType);
772      if (filler)
773        EmitInitializationToLValue(filler, elementLV);
774      else
775        EmitNullInitializationToLValue(elementLV);
776
777      // Move on to the next element.
778      llvm::Value *nextElement =
779        Builder.CreateInBoundsGEP(currentElement, one, "arrayinit.next");
780
781      // Tell the EH cleanup that we finished with the last element.
782      if (endOfInit) Builder.CreateStore(nextElement, endOfInit);
783
784      // Leave the loop if we're done.
785      llvm::Value *done = Builder.CreateICmpEQ(nextElement, end,
786                                               "arrayinit.done");
787      llvm::BasicBlock *endBB = CGF.createBasicBlock("arrayinit.end");
788      Builder.CreateCondBr(done, endBB, bodyBB);
789      currentElement->addIncoming(nextElement, Builder.GetInsertBlock());
790
791      CGF.EmitBlock(endBB);
792    }
793
794    // Leave the partial-array cleanup if we entered one.
795    if (dtorKind) CGF.DeactivateCleanupBlock(cleanup);
796
797    return;
798  }
799
800  assert(E->getType()->isRecordType() && "Only support structs/unions here!");
801
802  // Do struct initialization; this code just sets each individual member
803  // to the approprate value.  This makes bitfield support automatic;
804  // the disadvantage is that the generated code is more difficult for
805  // the optimizer, especially with bitfields.
806  unsigned NumInitElements = E->getNumInits();
807  RecordDecl *record = E->getType()->castAs<RecordType>()->getDecl();
808
809  if (record->isUnion()) {
810    // Only initialize one field of a union. The field itself is
811    // specified by the initializer list.
812    if (!E->getInitializedFieldInUnion()) {
813      // Empty union; we have nothing to do.
814
815#ifndef NDEBUG
816      // Make sure that it's really an empty and not a failure of
817      // semantic analysis.
818      for (RecordDecl::field_iterator Field = record->field_begin(),
819                                   FieldEnd = record->field_end();
820           Field != FieldEnd; ++Field)
821        assert(Field->isUnnamedBitfield() && "Only unnamed bitfields allowed");
822#endif
823      return;
824    }
825
826    // FIXME: volatility
827    FieldDecl *Field = E->getInitializedFieldInUnion();
828
829    LValue FieldLoc = CGF.EmitLValueForFieldInitialization(DestPtr, Field, 0);
830    if (NumInitElements) {
831      // Store the initializer into the field
832      EmitInitializationToLValue(E->getInit(0), FieldLoc);
833    } else {
834      // Default-initialize to null.
835      EmitNullInitializationToLValue(FieldLoc);
836    }
837
838    return;
839  }
840
841  // We'll need to enter cleanup scopes in case any of the member
842  // initializers throw an exception.
843  SmallVector<EHScopeStack::stable_iterator, 16> cleanups;
844
845  // Here we iterate over the fields; this makes it simpler to both
846  // default-initialize fields and skip over unnamed fields.
847  unsigned curInitIndex = 0;
848  for (RecordDecl::field_iterator field = record->field_begin(),
849                               fieldEnd = record->field_end();
850       field != fieldEnd; ++field) {
851    // We're done once we hit the flexible array member.
852    if (field->getType()->isIncompleteArrayType())
853      break;
854
855    // Always skip anonymous bitfields.
856    if (field->isUnnamedBitfield())
857      continue;
858
859    // We're done if we reach the end of the explicit initializers, we
860    // have a zeroed object, and the rest of the fields are
861    // zero-initializable.
862    if (curInitIndex == NumInitElements && Dest.isZeroed() &&
863        CGF.getTypes().isZeroInitializable(E->getType()))
864      break;
865
866    // FIXME: volatility
867    LValue LV = CGF.EmitLValueForFieldInitialization(DestPtr, *field, 0);
868    // We never generate write-barries for initialized fields.
869    LV.setNonGC(true);
870
871    if (curInitIndex < NumInitElements) {
872      // Store the initializer into the field.
873      EmitInitializationToLValue(E->getInit(curInitIndex++), LV);
874    } else {
875      // We're out of initalizers; default-initialize to null
876      EmitNullInitializationToLValue(LV);
877    }
878
879    // Push a destructor if necessary.
880    // FIXME: if we have an array of structures, all explicitly
881    // initialized, we can end up pushing a linear number of cleanups.
882    bool pushedCleanup = false;
883    if (QualType::DestructionKind dtorKind
884          = field->getType().isDestructedType()) {
885      assert(LV.isSimple());
886      if (CGF.needsEHCleanup(dtorKind)) {
887        CGF.pushDestroy(EHCleanup, LV.getAddress(), field->getType(),
888                        CGF.getDestroyer(dtorKind), false);
889        cleanups.push_back(CGF.EHStack.stable_begin());
890        pushedCleanup = true;
891      }
892    }
893
894    // If the GEP didn't get used because of a dead zero init or something
895    // else, clean it up for -O0 builds and general tidiness.
896    if (!pushedCleanup && LV.isSimple())
897      if (llvm::GetElementPtrInst *GEP =
898            dyn_cast<llvm::GetElementPtrInst>(LV.getAddress()))
899        if (GEP->use_empty())
900          GEP->eraseFromParent();
901  }
902
903  // Deactivate all the partial cleanups in reverse order, which
904  // generally means popping them.
905  for (unsigned i = cleanups.size(); i != 0; --i)
906    CGF.DeactivateCleanupBlock(cleanups[i-1]);
907}
908
909//===----------------------------------------------------------------------===//
910//                        Entry Points into this File
911//===----------------------------------------------------------------------===//
912
913/// GetNumNonZeroBytesInInit - Get an approximate count of the number of
914/// non-zero bytes that will be stored when outputting the initializer for the
915/// specified initializer expression.
916static CharUnits GetNumNonZeroBytesInInit(const Expr *E, CodeGenFunction &CGF) {
917  E = E->IgnoreParens();
918
919  // 0 and 0.0 won't require any non-zero stores!
920  if (isSimpleZero(E, CGF)) return CharUnits::Zero();
921
922  // If this is an initlist expr, sum up the size of sizes of the (present)
923  // elements.  If this is something weird, assume the whole thing is non-zero.
924  const InitListExpr *ILE = dyn_cast<InitListExpr>(E);
925  if (ILE == 0 || !CGF.getTypes().isZeroInitializable(ILE->getType()))
926    return CGF.getContext().getTypeSizeInChars(E->getType());
927
928  // InitListExprs for structs have to be handled carefully.  If there are
929  // reference members, we need to consider the size of the reference, not the
930  // referencee.  InitListExprs for unions and arrays can't have references.
931  if (const RecordType *RT = E->getType()->getAs<RecordType>()) {
932    if (!RT->isUnionType()) {
933      RecordDecl *SD = E->getType()->getAs<RecordType>()->getDecl();
934      CharUnits NumNonZeroBytes = CharUnits::Zero();
935
936      unsigned ILEElement = 0;
937      for (RecordDecl::field_iterator Field = SD->field_begin(),
938           FieldEnd = SD->field_end(); Field != FieldEnd; ++Field) {
939        // We're done once we hit the flexible array member or run out of
940        // InitListExpr elements.
941        if (Field->getType()->isIncompleteArrayType() ||
942            ILEElement == ILE->getNumInits())
943          break;
944        if (Field->isUnnamedBitfield())
945          continue;
946
947        const Expr *E = ILE->getInit(ILEElement++);
948
949        // Reference values are always non-null and have the width of a pointer.
950        if (Field->getType()->isReferenceType())
951          NumNonZeroBytes += CGF.getContext().toCharUnitsFromBits(
952              CGF.getContext().getTargetInfo().getPointerWidth(0));
953        else
954          NumNonZeroBytes += GetNumNonZeroBytesInInit(E, CGF);
955      }
956
957      return NumNonZeroBytes;
958    }
959  }
960
961
962  CharUnits NumNonZeroBytes = CharUnits::Zero();
963  for (unsigned i = 0, e = ILE->getNumInits(); i != e; ++i)
964    NumNonZeroBytes += GetNumNonZeroBytesInInit(ILE->getInit(i), CGF);
965  return NumNonZeroBytes;
966}
967
968/// CheckAggExprForMemSetUse - If the initializer is large and has a lot of
969/// zeros in it, emit a memset and avoid storing the individual zeros.
970///
971static void CheckAggExprForMemSetUse(AggValueSlot &Slot, const Expr *E,
972                                     CodeGenFunction &CGF) {
973  // If the slot is already known to be zeroed, nothing to do.  Don't mess with
974  // volatile stores.
975  if (Slot.isZeroed() || Slot.isVolatile() || Slot.getAddr() == 0) return;
976
977  // C++ objects with a user-declared constructor don't need zero'ing.
978  if (CGF.getContext().getLangOptions().CPlusPlus)
979    if (const RecordType *RT = CGF.getContext()
980                       .getBaseElementType(E->getType())->getAs<RecordType>()) {
981      const CXXRecordDecl *RD = cast<CXXRecordDecl>(RT->getDecl());
982      if (RD->hasUserDeclaredConstructor())
983        return;
984    }
985
986  // If the type is 16-bytes or smaller, prefer individual stores over memset.
987  std::pair<CharUnits, CharUnits> TypeInfo =
988    CGF.getContext().getTypeInfoInChars(E->getType());
989  if (TypeInfo.first <= CharUnits::fromQuantity(16))
990    return;
991
992  // Check to see if over 3/4 of the initializer are known to be zero.  If so,
993  // we prefer to emit memset + individual stores for the rest.
994  CharUnits NumNonZeroBytes = GetNumNonZeroBytesInInit(E, CGF);
995  if (NumNonZeroBytes*4 > TypeInfo.first)
996    return;
997
998  // Okay, it seems like a good idea to use an initial memset, emit the call.
999  llvm::Constant *SizeVal = CGF.Builder.getInt64(TypeInfo.first.getQuantity());
1000  CharUnits Align = TypeInfo.second;
1001
1002  llvm::Value *Loc = Slot.getAddr();
1003  llvm::Type *BP = llvm::Type::getInt8PtrTy(CGF.getLLVMContext());
1004
1005  Loc = CGF.Builder.CreateBitCast(Loc, BP);
1006  CGF.Builder.CreateMemSet(Loc, CGF.Builder.getInt8(0), SizeVal,
1007                           Align.getQuantity(), false);
1008
1009  // Tell the AggExprEmitter that the slot is known zero.
1010  Slot.setZeroed();
1011}
1012
1013
1014
1015
1016/// EmitAggExpr - Emit the computation of the specified expression of aggregate
1017/// type.  The result is computed into DestPtr.  Note that if DestPtr is null,
1018/// the value of the aggregate expression is not needed.  If VolatileDest is
1019/// true, DestPtr cannot be 0.
1020///
1021/// \param IsInitializer - true if this evaluation is initializing an
1022/// object whose lifetime is already being managed.
1023void CodeGenFunction::EmitAggExpr(const Expr *E, AggValueSlot Slot,
1024                                  bool IgnoreResult) {
1025  assert(E && hasAggregateLLVMType(E->getType()) &&
1026         "Invalid aggregate expression to emit");
1027  assert((Slot.getAddr() != 0 || Slot.isIgnored()) &&
1028         "slot has bits but no address");
1029
1030  // Optimize the slot if possible.
1031  CheckAggExprForMemSetUse(Slot, E, *this);
1032
1033  AggExprEmitter(*this, Slot, IgnoreResult).Visit(const_cast<Expr*>(E));
1034}
1035
1036LValue CodeGenFunction::EmitAggExprToLValue(const Expr *E) {
1037  assert(hasAggregateLLVMType(E->getType()) && "Invalid argument!");
1038  llvm::Value *Temp = CreateMemTemp(E->getType());
1039  LValue LV = MakeAddrLValue(Temp, E->getType());
1040  EmitAggExpr(E, AggValueSlot::forLValue(LV, AggValueSlot::IsNotDestructed,
1041                                         AggValueSlot::DoesNotNeedGCBarriers,
1042                                         AggValueSlot::IsNotAliased));
1043  return LV;
1044}
1045
1046void CodeGenFunction::EmitAggregateCopy(llvm::Value *DestPtr,
1047                                        llvm::Value *SrcPtr, QualType Ty,
1048                                        bool isVolatile) {
1049  assert(!Ty->isAnyComplexType() && "Shouldn't happen for complex");
1050
1051  if (getContext().getLangOptions().CPlusPlus) {
1052    if (const RecordType *RT = Ty->getAs<RecordType>()) {
1053      CXXRecordDecl *Record = cast<CXXRecordDecl>(RT->getDecl());
1054      assert((Record->hasTrivialCopyConstructor() ||
1055              Record->hasTrivialCopyAssignment() ||
1056              Record->hasTrivialMoveConstructor() ||
1057              Record->hasTrivialMoveAssignment()) &&
1058             "Trying to aggregate-copy a type without a trivial copy "
1059             "constructor or assignment operator");
1060      // Ignore empty classes in C++.
1061      if (Record->isEmpty())
1062        return;
1063    }
1064  }
1065
1066  // Aggregate assignment turns into llvm.memcpy.  This is almost valid per
1067  // C99 6.5.16.1p3, which states "If the value being stored in an object is
1068  // read from another object that overlaps in anyway the storage of the first
1069  // object, then the overlap shall be exact and the two objects shall have
1070  // qualified or unqualified versions of a compatible type."
1071  //
1072  // memcpy is not defined if the source and destination pointers are exactly
1073  // equal, but other compilers do this optimization, and almost every memcpy
1074  // implementation handles this case safely.  If there is a libc that does not
1075  // safely handle this, we can add a target hook.
1076
1077  // Get size and alignment info for this aggregate.
1078  std::pair<CharUnits, CharUnits> TypeInfo =
1079    getContext().getTypeInfoInChars(Ty);
1080
1081  // FIXME: Handle variable sized types.
1082
1083  // FIXME: If we have a volatile struct, the optimizer can remove what might
1084  // appear to be `extra' memory ops:
1085  //
1086  // volatile struct { int i; } a, b;
1087  //
1088  // int main() {
1089  //   a = b;
1090  //   a = b;
1091  // }
1092  //
1093  // we need to use a different call here.  We use isVolatile to indicate when
1094  // either the source or the destination is volatile.
1095
1096  llvm::PointerType *DPT = cast<llvm::PointerType>(DestPtr->getType());
1097  llvm::Type *DBP =
1098    llvm::Type::getInt8PtrTy(getLLVMContext(), DPT->getAddressSpace());
1099  DestPtr = Builder.CreateBitCast(DestPtr, DBP);
1100
1101  llvm::PointerType *SPT = cast<llvm::PointerType>(SrcPtr->getType());
1102  llvm::Type *SBP =
1103    llvm::Type::getInt8PtrTy(getLLVMContext(), SPT->getAddressSpace());
1104  SrcPtr = Builder.CreateBitCast(SrcPtr, SBP);
1105
1106  // Don't do any of the memmove_collectable tests if GC isn't set.
1107  if (CGM.getLangOptions().getGC() == LangOptions::NonGC) {
1108    // fall through
1109  } else if (const RecordType *RecordTy = Ty->getAs<RecordType>()) {
1110    RecordDecl *Record = RecordTy->getDecl();
1111    if (Record->hasObjectMember()) {
1112      CharUnits size = TypeInfo.first;
1113      llvm::Type *SizeTy = ConvertType(getContext().getSizeType());
1114      llvm::Value *SizeVal = llvm::ConstantInt::get(SizeTy, size.getQuantity());
1115      CGM.getObjCRuntime().EmitGCMemmoveCollectable(*this, DestPtr, SrcPtr,
1116                                                    SizeVal);
1117      return;
1118    }
1119  } else if (Ty->isArrayType()) {
1120    QualType BaseType = getContext().getBaseElementType(Ty);
1121    if (const RecordType *RecordTy = BaseType->getAs<RecordType>()) {
1122      if (RecordTy->getDecl()->hasObjectMember()) {
1123        CharUnits size = TypeInfo.first;
1124        llvm::Type *SizeTy = ConvertType(getContext().getSizeType());
1125        llvm::Value *SizeVal =
1126          llvm::ConstantInt::get(SizeTy, size.getQuantity());
1127        CGM.getObjCRuntime().EmitGCMemmoveCollectable(*this, DestPtr, SrcPtr,
1128                                                      SizeVal);
1129        return;
1130      }
1131    }
1132  }
1133
1134  Builder.CreateMemCpy(DestPtr, SrcPtr,
1135                       llvm::ConstantInt::get(IntPtrTy,
1136                                              TypeInfo.first.getQuantity()),
1137                       TypeInfo.second.getQuantity(), isVolatile);
1138}
1139