CGExprAgg.cpp revision 224145 
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  ReturnValueSlot getReturnValueSlot() const {
39    // If the destination slot requires garbage collection, we can't
40    // use the real return value slot, because we have to use the GC
41    // API.
42    if (Dest.requiresGCollection()) return ReturnValueSlot();
43
44    return ReturnValueSlot(Dest.getAddr(), Dest.isVolatile());
45  }
46
47  AggValueSlot EnsureSlot(QualType T) {
48    if (!Dest.isIgnored()) return Dest;
49    return CGF.CreateAggTemp(T, "agg.tmp.ensured");
50  }
51
52public:
53  AggExprEmitter(CodeGenFunction &cgf, AggValueSlot Dest,
54                 bool ignore)
55    : CGF(cgf), Builder(CGF.Builder), Dest(Dest),
56      IgnoreResult(ignore) {
57  }
58
59  //===--------------------------------------------------------------------===//
60  //                               Utilities
61  //===--------------------------------------------------------------------===//
62
63  /// EmitAggLoadOfLValue - Given an expression with aggregate type that
64  /// represents a value lvalue, this method emits the address of the lvalue,
65  /// then loads the result into DestPtr.
66  void EmitAggLoadOfLValue(const Expr *E);
67
68  /// EmitFinalDestCopy - Perform the final copy to DestPtr, if desired.
69  void EmitFinalDestCopy(const Expr *E, LValue Src, bool Ignore = false);
70  void EmitFinalDestCopy(const Expr *E, RValue Src, bool Ignore = false);
71
72  void EmitGCMove(const Expr *E, RValue Src);
73
74  bool TypeRequiresGCollection(QualType T);
75
76  //===--------------------------------------------------------------------===//
77  //                            Visitor Methods
78  //===--------------------------------------------------------------------===//
79
80  void VisitStmt(Stmt *S) {
81    CGF.ErrorUnsupported(S, "aggregate expression");
82  }
83  void VisitParenExpr(ParenExpr *PE) { Visit(PE->getSubExpr()); }
84  void VisitGenericSelectionExpr(GenericSelectionExpr *GE) {
85    Visit(GE->getResultExpr());
86  }
87  void VisitUnaryExtension(UnaryOperator *E) { Visit(E->getSubExpr()); }
88  void VisitSubstNonTypeTemplateParmExpr(SubstNonTypeTemplateParmExpr *E) {
89    return Visit(E->getReplacement());
90  }
91
92  // l-values.
93  void VisitDeclRefExpr(DeclRefExpr *DRE) { EmitAggLoadOfLValue(DRE); }
94  void VisitMemberExpr(MemberExpr *ME) { EmitAggLoadOfLValue(ME); }
95  void VisitUnaryDeref(UnaryOperator *E) { EmitAggLoadOfLValue(E); }
96  void VisitStringLiteral(StringLiteral *E) { EmitAggLoadOfLValue(E); }
97  void VisitCompoundLiteralExpr(CompoundLiteralExpr *E);
98  void VisitArraySubscriptExpr(ArraySubscriptExpr *E) {
99    EmitAggLoadOfLValue(E);
100  }
101  void VisitBlockDeclRefExpr(const BlockDeclRefExpr *E) {
102    EmitAggLoadOfLValue(E);
103  }
104  void VisitPredefinedExpr(const PredefinedExpr *E) {
105    EmitAggLoadOfLValue(E);
106  }
107
108  // Operators.
109  void VisitCastExpr(CastExpr *E);
110  void VisitCallExpr(const CallExpr *E);
111  void VisitStmtExpr(const StmtExpr *E);
112  void VisitBinaryOperator(const BinaryOperator *BO);
113  void VisitPointerToDataMemberBinaryOperator(const BinaryOperator *BO);
114  void VisitBinAssign(const BinaryOperator *E);
115  void VisitBinComma(const BinaryOperator *E);
116
117  void VisitObjCMessageExpr(ObjCMessageExpr *E);
118  void VisitObjCIvarRefExpr(ObjCIvarRefExpr *E) {
119    EmitAggLoadOfLValue(E);
120  }
121  void VisitObjCPropertyRefExpr(ObjCPropertyRefExpr *E);
122
123  void VisitAbstractConditionalOperator(const AbstractConditionalOperator *CO);
124  void VisitChooseExpr(const ChooseExpr *CE);
125  void VisitInitListExpr(InitListExpr *E);
126  void VisitImplicitValueInitExpr(ImplicitValueInitExpr *E);
127  void VisitCXXDefaultArgExpr(CXXDefaultArgExpr *DAE) {
128    Visit(DAE->getExpr());
129  }
130  void VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E);
131  void VisitCXXConstructExpr(const CXXConstructExpr *E);
132  void VisitExprWithCleanups(ExprWithCleanups *E);
133  void VisitCXXScalarValueInitExpr(CXXScalarValueInitExpr *E);
134  void VisitCXXTypeidExpr(CXXTypeidExpr *E) { EmitAggLoadOfLValue(E); }
135  void VisitMaterializeTemporaryExpr(MaterializeTemporaryExpr *E);
136  void VisitOpaqueValueExpr(OpaqueValueExpr *E);
137
138  void VisitVAArgExpr(VAArgExpr *E);
139
140  void EmitInitializationToLValue(Expr *E, LValue Address);
141  void EmitNullInitializationToLValue(LValue Address);
142  //  case Expr::ChooseExprClass:
143  void VisitCXXThrowExpr(const CXXThrowExpr *E) { CGF.EmitCXXThrowExpr(E); }
144};
145}  // end anonymous namespace.
146
147//===----------------------------------------------------------------------===//
148//                                Utilities
149//===----------------------------------------------------------------------===//
150
151/// EmitAggLoadOfLValue - Given an expression with aggregate type that
152/// represents a value lvalue, this method emits the address of the lvalue,
153/// then loads the result into DestPtr.
154void AggExprEmitter::EmitAggLoadOfLValue(const Expr *E) {
155  LValue LV = CGF.EmitLValue(E);
156  EmitFinalDestCopy(E, LV);
157}
158
159/// \brief True if the given aggregate type requires special GC API calls.
160bool AggExprEmitter::TypeRequiresGCollection(QualType T) {
161  // Only record types have members that might require garbage collection.
162  const RecordType *RecordTy = T->getAs<RecordType>();
163  if (!RecordTy) return false;
164
165  // Don't mess with non-trivial C++ types.
166  RecordDecl *Record = RecordTy->getDecl();
167  if (isa<CXXRecordDecl>(Record) &&
168      (!cast<CXXRecordDecl>(Record)->hasTrivialCopyConstructor() ||
169       !cast<CXXRecordDecl>(Record)->hasTrivialDestructor()))
170    return false;
171
172  // Check whether the type has an object member.
173  return Record->hasObjectMember();
174}
175
176/// \brief Perform the final move to DestPtr if RequiresGCollection is set.
177///
178/// The idea is that you do something like this:
179///   RValue Result = EmitSomething(..., getReturnValueSlot());
180///   EmitGCMove(E, Result);
181/// If GC doesn't interfere, this will cause the result to be emitted
182/// directly into the return value slot.  If GC does interfere, a final
183/// move will be performed.
184void AggExprEmitter::EmitGCMove(const Expr *E, RValue Src) {
185  if (Dest.requiresGCollection()) {
186    CharUnits size = CGF.getContext().getTypeSizeInChars(E->getType());
187    const llvm::Type *SizeTy = CGF.ConvertType(CGF.getContext().getSizeType());
188    llvm::Value *SizeVal = llvm::ConstantInt::get(SizeTy, size.getQuantity());
189    CGF.CGM.getObjCRuntime().EmitGCMemmoveCollectable(CGF, Dest.getAddr(),
190                                                    Src.getAggregateAddr(),
191                                                    SizeVal);
192  }
193}
194
195/// EmitFinalDestCopy - Perform the final copy to DestPtr, if desired.
196void AggExprEmitter::EmitFinalDestCopy(const Expr *E, RValue Src, bool Ignore) {
197  assert(Src.isAggregate() && "value must be aggregate value!");
198
199  // If Dest is ignored, then we're evaluating an aggregate expression
200  // in a context (like an expression statement) that doesn't care
201  // about the result.  C says that an lvalue-to-rvalue conversion is
202  // performed in these cases; C++ says that it is not.  In either
203  // case, we don't actually need to do anything unless the value is
204  // volatile.
205  if (Dest.isIgnored()) {
206    if (!Src.isVolatileQualified() ||
207        CGF.CGM.getLangOptions().CPlusPlus ||
208        (IgnoreResult && Ignore))
209      return;
210
211    // If the source is volatile, we must read from it; to do that, we need
212    // some place to put it.
213    Dest = CGF.CreateAggTemp(E->getType(), "agg.tmp");
214  }
215
216  if (Dest.requiresGCollection()) {
217    CharUnits size = CGF.getContext().getTypeSizeInChars(E->getType());
218    const llvm::Type *SizeTy = CGF.ConvertType(CGF.getContext().getSizeType());
219    llvm::Value *SizeVal = llvm::ConstantInt::get(SizeTy, size.getQuantity());
220    CGF.CGM.getObjCRuntime().EmitGCMemmoveCollectable(CGF,
221                                                      Dest.getAddr(),
222                                                      Src.getAggregateAddr(),
223                                                      SizeVal);
224    return;
225  }
226  // If the result of the assignment is used, copy the LHS there also.
227  // FIXME: Pass VolatileDest as well.  I think we also need to merge volatile
228  // from the source as well, as we can't eliminate it if either operand
229  // is volatile, unless copy has volatile for both source and destination..
230  CGF.EmitAggregateCopy(Dest.getAddr(), Src.getAggregateAddr(), E->getType(),
231                        Dest.isVolatile()|Src.isVolatileQualified());
232}
233
234/// EmitFinalDestCopy - Perform the final copy to DestPtr, if desired.
235void AggExprEmitter::EmitFinalDestCopy(const Expr *E, LValue Src, bool Ignore) {
236  assert(Src.isSimple() && "Can't have aggregate bitfield, vector, etc");
237
238  EmitFinalDestCopy(E, RValue::getAggregate(Src.getAddress(),
239                                            Src.isVolatileQualified()),
240                    Ignore);
241}
242
243//===----------------------------------------------------------------------===//
244//                            Visitor Methods
245//===----------------------------------------------------------------------===//
246
247void AggExprEmitter::VisitMaterializeTemporaryExpr(MaterializeTemporaryExpr *E){
248  Visit(E->GetTemporaryExpr());
249}
250
251void AggExprEmitter::VisitOpaqueValueExpr(OpaqueValueExpr *e) {
252  EmitFinalDestCopy(e, CGF.getOpaqueLValueMapping(e));
253}
254
255void
256AggExprEmitter::VisitCompoundLiteralExpr(CompoundLiteralExpr *E) {
257  if (E->getType().isPODType(CGF.getContext())) {
258    // For a POD type, just emit a load of the lvalue + a copy, because our
259    // compound literal might alias the destination.
260    // FIXME: This is a band-aid; the real problem appears to be in our handling
261    // of assignments, where we store directly into the LHS without checking
262    // whether anything in the RHS aliases.
263    EmitAggLoadOfLValue(E);
264    return;
265  }
266
267  AggValueSlot Slot = EnsureSlot(E->getType());
268  CGF.EmitAggExpr(E->getInitializer(), Slot);
269}
270
271
272void AggExprEmitter::VisitCastExpr(CastExpr *E) {
273  switch (E->getCastKind()) {
274  case CK_Dynamic: {
275    assert(isa<CXXDynamicCastExpr>(E) && "CK_Dynamic without a dynamic_cast?");
276    LValue LV = CGF.EmitCheckedLValue(E->getSubExpr());
277    // FIXME: Do we also need to handle property references here?
278    if (LV.isSimple())
279      CGF.EmitDynamicCast(LV.getAddress(), cast<CXXDynamicCastExpr>(E));
280    else
281      CGF.CGM.ErrorUnsupported(E, "non-simple lvalue dynamic_cast");
282
283    if (!Dest.isIgnored())
284      CGF.CGM.ErrorUnsupported(E, "lvalue dynamic_cast with a destination");
285    break;
286  }
287
288  case CK_ToUnion: {
289    if (Dest.isIgnored()) break;
290
291    // GCC union extension
292    QualType Ty = E->getSubExpr()->getType();
293    QualType PtrTy = CGF.getContext().getPointerType(Ty);
294    llvm::Value *CastPtr = Builder.CreateBitCast(Dest.getAddr(),
295                                                 CGF.ConvertType(PtrTy));
296    EmitInitializationToLValue(E->getSubExpr(),
297                               CGF.MakeAddrLValue(CastPtr, Ty));
298    break;
299  }
300
301  case CK_DerivedToBase:
302  case CK_BaseToDerived:
303  case CK_UncheckedDerivedToBase: {
304    assert(0 && "cannot perform hierarchy conversion in EmitAggExpr: "
305                "should have been unpacked before we got here");
306    break;
307  }
308
309  case CK_GetObjCProperty: {
310    LValue LV = CGF.EmitLValue(E->getSubExpr());
311    assert(LV.isPropertyRef());
312    RValue RV = CGF.EmitLoadOfPropertyRefLValue(LV, getReturnValueSlot());
313    EmitGCMove(E, RV);
314    break;
315  }
316
317  case CK_LValueToRValue: // hope for downstream optimization
318  case CK_NoOp:
319  case CK_UserDefinedConversion:
320  case CK_ConstructorConversion:
321    assert(CGF.getContext().hasSameUnqualifiedType(E->getSubExpr()->getType(),
322                                                   E->getType()) &&
323           "Implicit cast types must be compatible");
324    Visit(E->getSubExpr());
325    break;
326
327  case CK_LValueBitCast:
328    llvm_unreachable("should not be emitting lvalue bitcast as rvalue");
329    break;
330
331  case CK_Dependent:
332  case CK_BitCast:
333  case CK_ArrayToPointerDecay:
334  case CK_FunctionToPointerDecay:
335  case CK_NullToPointer:
336  case CK_NullToMemberPointer:
337  case CK_BaseToDerivedMemberPointer:
338  case CK_DerivedToBaseMemberPointer:
339  case CK_MemberPointerToBoolean:
340  case CK_IntegralToPointer:
341  case CK_PointerToIntegral:
342  case CK_PointerToBoolean:
343  case CK_ToVoid:
344  case CK_VectorSplat:
345  case CK_IntegralCast:
346  case CK_IntegralToBoolean:
347  case CK_IntegralToFloating:
348  case CK_FloatingToIntegral:
349  case CK_FloatingToBoolean:
350  case CK_FloatingCast:
351  case CK_AnyPointerToObjCPointerCast:
352  case CK_AnyPointerToBlockPointerCast:
353  case CK_ObjCObjectLValueCast:
354  case CK_FloatingRealToComplex:
355  case CK_FloatingComplexToReal:
356  case CK_FloatingComplexToBoolean:
357  case CK_FloatingComplexCast:
358  case CK_FloatingComplexToIntegralComplex:
359  case CK_IntegralRealToComplex:
360  case CK_IntegralComplexToReal:
361  case CK_IntegralComplexToBoolean:
362  case CK_IntegralComplexCast:
363  case CK_IntegralComplexToFloatingComplex:
364  case CK_ObjCProduceObject:
365  case CK_ObjCConsumeObject:
366  case CK_ObjCReclaimReturnedObject:
367    llvm_unreachable("cast kind invalid for aggregate types");
368  }
369}
370
371void AggExprEmitter::VisitCallExpr(const CallExpr *E) {
372  if (E->getCallReturnType()->isReferenceType()) {
373    EmitAggLoadOfLValue(E);
374    return;
375  }
376
377  RValue RV = CGF.EmitCallExpr(E, getReturnValueSlot());
378  EmitGCMove(E, RV);
379}
380
381void AggExprEmitter::VisitObjCMessageExpr(ObjCMessageExpr *E) {
382  RValue RV = CGF.EmitObjCMessageExpr(E, getReturnValueSlot());
383  EmitGCMove(E, RV);
384}
385
386void AggExprEmitter::VisitObjCPropertyRefExpr(ObjCPropertyRefExpr *E) {
387  llvm_unreachable("direct property access not surrounded by "
388                   "lvalue-to-rvalue cast");
389}
390
391void AggExprEmitter::VisitBinComma(const BinaryOperator *E) {
392  CGF.EmitIgnoredExpr(E->getLHS());
393  Visit(E->getRHS());
394}
395
396void AggExprEmitter::VisitStmtExpr(const StmtExpr *E) {
397  CodeGenFunction::StmtExprEvaluation eval(CGF);
398  CGF.EmitCompoundStmt(*E->getSubStmt(), true, Dest);
399}
400
401void AggExprEmitter::VisitBinaryOperator(const BinaryOperator *E) {
402  if (E->getOpcode() == BO_PtrMemD || E->getOpcode() == BO_PtrMemI)
403    VisitPointerToDataMemberBinaryOperator(E);
404  else
405    CGF.ErrorUnsupported(E, "aggregate binary expression");
406}
407
408void AggExprEmitter::VisitPointerToDataMemberBinaryOperator(
409                                                    const BinaryOperator *E) {
410  LValue LV = CGF.EmitPointerToDataMemberBinaryExpr(E);
411  EmitFinalDestCopy(E, LV);
412}
413
414void AggExprEmitter::VisitBinAssign(const BinaryOperator *E) {
415  // For an assignment to work, the value on the right has
416  // to be compatible with the value on the left.
417  assert(CGF.getContext().hasSameUnqualifiedType(E->getLHS()->getType(),
418                                                 E->getRHS()->getType())
419         && "Invalid assignment");
420
421  if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E->getLHS()))
422    if (const VarDecl *VD = dyn_cast<VarDecl>(DRE->getDecl()))
423      if (VD->hasAttr<BlocksAttr>() &&
424          E->getRHS()->HasSideEffects(CGF.getContext())) {
425        // When __block variable on LHS, the RHS must be evaluated first
426        // as it may change the 'forwarding' field via call to Block_copy.
427        LValue RHS = CGF.EmitLValue(E->getRHS());
428        LValue LHS = CGF.EmitLValue(E->getLHS());
429        bool GCollection = false;
430        if (CGF.getContext().getLangOptions().getGCMode())
431          GCollection = TypeRequiresGCollection(E->getLHS()->getType());
432        Dest = AggValueSlot::forLValue(LHS, true, GCollection);
433        EmitFinalDestCopy(E, RHS, true);
434        return;
435      }
436
437  LValue LHS = CGF.EmitLValue(E->getLHS());
438
439  // We have to special case property setters, otherwise we must have
440  // a simple lvalue (no aggregates inside vectors, bitfields).
441  if (LHS.isPropertyRef()) {
442    const ObjCPropertyRefExpr *RE = LHS.getPropertyRefExpr();
443    QualType ArgType = RE->getSetterArgType();
444    RValue Src;
445    if (ArgType->isReferenceType())
446      Src = CGF.EmitReferenceBindingToExpr(E->getRHS(), 0);
447    else {
448      AggValueSlot Slot = EnsureSlot(E->getRHS()->getType());
449      CGF.EmitAggExpr(E->getRHS(), Slot);
450      Src = Slot.asRValue();
451    }
452    CGF.EmitStoreThroughPropertyRefLValue(Src, LHS);
453  } else {
454    bool GCollection = false;
455    if (CGF.getContext().getLangOptions().getGCMode())
456      GCollection = TypeRequiresGCollection(E->getLHS()->getType());
457
458    // Codegen the RHS so that it stores directly into the LHS.
459    AggValueSlot LHSSlot = AggValueSlot::forLValue(LHS, true,
460                                                   GCollection);
461    CGF.EmitAggExpr(E->getRHS(), LHSSlot, false);
462    EmitFinalDestCopy(E, LHS, true);
463  }
464}
465
466void AggExprEmitter::
467VisitAbstractConditionalOperator(const AbstractConditionalOperator *E) {
468  llvm::BasicBlock *LHSBlock = CGF.createBasicBlock("cond.true");
469  llvm::BasicBlock *RHSBlock = CGF.createBasicBlock("cond.false");
470  llvm::BasicBlock *ContBlock = CGF.createBasicBlock("cond.end");
471
472  // Bind the common expression if necessary.
473  CodeGenFunction::OpaqueValueMapping binding(CGF, E);
474
475  CodeGenFunction::ConditionalEvaluation eval(CGF);
476  CGF.EmitBranchOnBoolExpr(E->getCond(), LHSBlock, RHSBlock);
477
478  // Save whether the destination's lifetime is externally managed.
479  bool DestLifetimeManaged = Dest.isLifetimeExternallyManaged();
480
481  eval.begin(CGF);
482  CGF.EmitBlock(LHSBlock);
483  Visit(E->getTrueExpr());
484  eval.end(CGF);
485
486  assert(CGF.HaveInsertPoint() && "expression evaluation ended with no IP!");
487  CGF.Builder.CreateBr(ContBlock);
488
489  // If the result of an agg expression is unused, then the emission
490  // of the LHS might need to create a destination slot.  That's fine
491  // with us, and we can safely emit the RHS into the same slot, but
492  // we shouldn't claim that its lifetime is externally managed.
493  Dest.setLifetimeExternallyManaged(DestLifetimeManaged);
494
495  eval.begin(CGF);
496  CGF.EmitBlock(RHSBlock);
497  Visit(E->getFalseExpr());
498  eval.end(CGF);
499
500  CGF.EmitBlock(ContBlock);
501}
502
503void AggExprEmitter::VisitChooseExpr(const ChooseExpr *CE) {
504  Visit(CE->getChosenSubExpr(CGF.getContext()));
505}
506
507void AggExprEmitter::VisitVAArgExpr(VAArgExpr *VE) {
508  llvm::Value *ArgValue = CGF.EmitVAListRef(VE->getSubExpr());
509  llvm::Value *ArgPtr = CGF.EmitVAArg(ArgValue, VE->getType());
510
511  if (!ArgPtr) {
512    CGF.ErrorUnsupported(VE, "aggregate va_arg expression");
513    return;
514  }
515
516  EmitFinalDestCopy(VE, CGF.MakeAddrLValue(ArgPtr, VE->getType()));
517}
518
519void AggExprEmitter::VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E) {
520  // Ensure that we have a slot, but if we already do, remember
521  // whether its lifetime was externally managed.
522  bool WasManaged = Dest.isLifetimeExternallyManaged();
523  Dest = EnsureSlot(E->getType());
524  Dest.setLifetimeExternallyManaged();
525
526  Visit(E->getSubExpr());
527
528  // Set up the temporary's destructor if its lifetime wasn't already
529  // being managed.
530  if (!WasManaged)
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, true, false,
600                                               Dest.isZeroed()));
601  } else if (LV.isSimple()) {
602    CGF.EmitScalarInit(E, /*D=*/0, LV, /*Captured=*/false);
603  } else {
604    CGF.EmitStoreThroughLValue(RValue::get(CGF.EmitScalarExpr(E)), LV);
605  }
606}
607
608void AggExprEmitter::EmitNullInitializationToLValue(LValue lv) {
609  QualType type = lv.getType();
610
611  // If the destination slot is already zeroed out before the aggregate is
612  // copied into it, we don't have to emit any zeros here.
613  if (Dest.isZeroed() && CGF.getTypes().isZeroInitializable(type))
614    return;
615
616  if (!CGF.hasAggregateLLVMType(type)) {
617    // For non-aggregates, we can store zero
618    llvm::Value *null = llvm::Constant::getNullValue(CGF.ConvertType(type));
619    CGF.EmitStoreThroughLValue(RValue::get(null), lv);
620  } else {
621    // There's a potential optimization opportunity in combining
622    // memsets; that would be easy for arrays, but relatively
623    // difficult for structures with the current code.
624    CGF.EmitNullInitialization(lv.getAddress(), lv.getType());
625  }
626}
627
628void AggExprEmitter::VisitInitListExpr(InitListExpr *E) {
629#if 0
630  // FIXME: Assess perf here?  Figure out what cases are worth optimizing here
631  // (Length of globals? Chunks of zeroed-out space?).
632  //
633  // If we can, prefer a copy from a global; this is a lot less code for long
634  // globals, and it's easier for the current optimizers to analyze.
635  if (llvm::Constant* C = CGF.CGM.EmitConstantExpr(E, E->getType(), &CGF)) {
636    llvm::GlobalVariable* GV =
637    new llvm::GlobalVariable(CGF.CGM.getModule(), C->getType(), true,
638                             llvm::GlobalValue::InternalLinkage, C, "");
639    EmitFinalDestCopy(E, CGF.MakeAddrLValue(GV, E->getType()));
640    return;
641  }
642#endif
643  if (E->hadArrayRangeDesignator())
644    CGF.ErrorUnsupported(E, "GNU array range designator extension");
645
646  llvm::Value *DestPtr = Dest.getAddr();
647
648  // Handle initialization of an array.
649  if (E->getType()->isArrayType()) {
650    const llvm::PointerType *APType =
651      cast<llvm::PointerType>(DestPtr->getType());
652    const llvm::ArrayType *AType =
653      cast<llvm::ArrayType>(APType->getElementType());
654
655    uint64_t NumInitElements = E->getNumInits();
656
657    if (E->getNumInits() > 0) {
658      QualType T1 = E->getType();
659      QualType T2 = E->getInit(0)->getType();
660      if (CGF.getContext().hasSameUnqualifiedType(T1, T2)) {
661        EmitAggLoadOfLValue(E->getInit(0));
662        return;
663      }
664    }
665
666    uint64_t NumArrayElements = AType->getNumElements();
667    assert(NumInitElements <= NumArrayElements);
668
669    QualType elementType = E->getType().getCanonicalType();
670    elementType = CGF.getContext().getQualifiedType(
671                    cast<ArrayType>(elementType)->getElementType(),
672                    elementType.getQualifiers() + Dest.getQualifiers());
673
674    // DestPtr is an array*.  Construct an elementType* by drilling
675    // down a level.
676    llvm::Value *zero = llvm::ConstantInt::get(CGF.SizeTy, 0);
677    llvm::Value *indices[] = { zero, zero };
678    llvm::Value *begin =
679      Builder.CreateInBoundsGEP(DestPtr, indices, indices+2, "arrayinit.begin");
680
681    // Exception safety requires us to destroy all the
682    // already-constructed members if an initializer throws.
683    // For that, we'll need an EH cleanup.
684    QualType::DestructionKind dtorKind = elementType.isDestructedType();
685    llvm::AllocaInst *endOfInit = 0;
686    EHScopeStack::stable_iterator cleanup;
687    if (CGF.needsEHCleanup(dtorKind)) {
688      // In principle we could tell the cleanup where we are more
689      // directly, but the control flow can get so varied here that it
690      // would actually be quite complex.  Therefore we go through an
691      // alloca.
692      endOfInit = CGF.CreateTempAlloca(begin->getType(),
693                                       "arrayinit.endOfInit");
694      Builder.CreateStore(begin, endOfInit);
695      CGF.pushIrregularPartialArrayCleanup(begin, endOfInit, elementType,
696                                           CGF.getDestroyer(dtorKind));
697      cleanup = CGF.EHStack.stable_begin();
698
699    // Otherwise, remember that we didn't need a cleanup.
700    } else {
701      dtorKind = QualType::DK_none;
702    }
703
704    llvm::Value *one = llvm::ConstantInt::get(CGF.SizeTy, 1);
705
706    // The 'current element to initialize'.  The invariants on this
707    // variable are complicated.  Essentially, after each iteration of
708    // the loop, it points to the last initialized element, except
709    // that it points to the beginning of the array before any
710    // elements have been initialized.
711    llvm::Value *element = begin;
712
713    // Emit the explicit initializers.
714    for (uint64_t i = 0; i != NumInitElements; ++i) {
715      // Advance to the next element.
716      if (i > 0) {
717        element = Builder.CreateInBoundsGEP(element, one, "arrayinit.element");
718
719        // Tell the cleanup that it needs to destroy up to this
720        // element.  TODO: some of these stores can be trivially
721        // observed to be unnecessary.
722        if (endOfInit) Builder.CreateStore(element, endOfInit);
723      }
724
725      LValue elementLV = CGF.MakeAddrLValue(element, elementType);
726      EmitInitializationToLValue(E->getInit(i), elementLV);
727    }
728
729    // Check whether there's a non-trivial array-fill expression.
730    // Note that this will be a CXXConstructExpr even if the element
731    // type is an array (or array of array, etc.) of class type.
732    Expr *filler = E->getArrayFiller();
733    bool hasTrivialFiller = true;
734    if (CXXConstructExpr *cons = dyn_cast_or_null<CXXConstructExpr>(filler)) {
735      assert(cons->getConstructor()->isDefaultConstructor());
736      hasTrivialFiller = cons->getConstructor()->isTrivial();
737    }
738
739    // Any remaining elements need to be zero-initialized, possibly
740    // using the filler expression.  We can skip this if the we're
741    // emitting to zeroed memory.
742    if (NumInitElements != NumArrayElements &&
743        !(Dest.isZeroed() && hasTrivialFiller &&
744          CGF.getTypes().isZeroInitializable(elementType))) {
745
746      // Use an actual loop.  This is basically
747      //   do { *array++ = filler; } while (array != end);
748
749      // Advance to the start of the rest of the array.
750      if (NumInitElements) {
751        element = Builder.CreateInBoundsGEP(element, one, "arrayinit.start");
752        if (endOfInit) Builder.CreateStore(element, endOfInit);
753      }
754
755      // Compute the end of the array.
756      llvm::Value *end = Builder.CreateInBoundsGEP(begin,
757                        llvm::ConstantInt::get(CGF.SizeTy, NumArrayElements),
758                                                   "arrayinit.end");
759
760      llvm::BasicBlock *entryBB = Builder.GetInsertBlock();
761      llvm::BasicBlock *bodyBB = CGF.createBasicBlock("arrayinit.body");
762
763      // Jump into the body.
764      CGF.EmitBlock(bodyBB);
765      llvm::PHINode *currentElement =
766        Builder.CreatePHI(element->getType(), 2, "arrayinit.cur");
767      currentElement->addIncoming(element, entryBB);
768
769      // Emit the actual filler expression.
770      LValue elementLV = CGF.MakeAddrLValue(currentElement, elementType);
771      if (filler)
772        EmitInitializationToLValue(filler, elementLV);
773      else
774        EmitNullInitializationToLValue(elementLV);
775
776      // Move on to the next element.
777      llvm::Value *nextElement =
778        Builder.CreateInBoundsGEP(currentElement, one, "arrayinit.next");
779
780      // Tell the EH cleanup that we finished with the last element.
781      if (endOfInit) Builder.CreateStore(nextElement, endOfInit);
782
783      // Leave the loop if we're done.
784      llvm::Value *done = Builder.CreateICmpEQ(nextElement, end,
785                                               "arrayinit.done");
786      llvm::BasicBlock *endBB = CGF.createBasicBlock("arrayinit.end");
787      Builder.CreateCondBr(done, endBB, bodyBB);
788      currentElement->addIncoming(nextElement, Builder.GetInsertBlock());
789
790      CGF.EmitBlock(endBB);
791    }
792
793    // Leave the partial-array cleanup if we entered one.
794    if (dtorKind) CGF.DeactivateCleanupBlock(cleanup);
795
796    return;
797  }
798
799  assert(E->getType()->isRecordType() && "Only support structs/unions here!");
800
801  // Do struct initialization; this code just sets each individual member
802  // to the approprate value.  This makes bitfield support automatic;
803  // the disadvantage is that the generated code is more difficult for
804  // the optimizer, especially with bitfields.
805  unsigned NumInitElements = E->getNumInits();
806  RecordDecl *record = E->getType()->castAs<RecordType>()->getDecl();
807
808  if (record->isUnion()) {
809    // Only initialize one field of a union. The field itself is
810    // specified by the initializer list.
811    if (!E->getInitializedFieldInUnion()) {
812      // Empty union; we have nothing to do.
813
814#ifndef NDEBUG
815      // Make sure that it's really an empty and not a failure of
816      // semantic analysis.
817      for (RecordDecl::field_iterator Field = record->field_begin(),
818                                   FieldEnd = record->field_end();
819           Field != FieldEnd; ++Field)
820        assert(Field->isUnnamedBitfield() && "Only unnamed bitfields allowed");
821#endif
822      return;
823    }
824
825    // FIXME: volatility
826    FieldDecl *Field = E->getInitializedFieldInUnion();
827
828    LValue FieldLoc = CGF.EmitLValueForFieldInitialization(DestPtr, Field, 0);
829    if (NumInitElements) {
830      // Store the initializer into the field
831      EmitInitializationToLValue(E->getInit(0), FieldLoc);
832    } else {
833      // Default-initialize to null.
834      EmitNullInitializationToLValue(FieldLoc);
835    }
836
837    return;
838  }
839
840  // We'll need to enter cleanup scopes in case any of the member
841  // initializers throw an exception.
842  llvm::SmallVector<EHScopeStack::stable_iterator, 16> cleanups;
843
844  // Here we iterate over the fields; this makes it simpler to both
845  // default-initialize fields and skip over unnamed fields.
846  unsigned curInitIndex = 0;
847  for (RecordDecl::field_iterator field = record->field_begin(),
848                               fieldEnd = record->field_end();
849       field != fieldEnd; ++field) {
850    // We're done once we hit the flexible array member.
851    if (field->getType()->isIncompleteArrayType())
852      break;
853
854    // Always skip anonymous bitfields.
855    if (field->isUnnamedBitfield())
856      continue;
857
858    // We're done if we reach the end of the explicit initializers, we
859    // have a zeroed object, and the rest of the fields are
860    // zero-initializable.
861    if (curInitIndex == NumInitElements && Dest.isZeroed() &&
862        CGF.getTypes().isZeroInitializable(E->getType()))
863      break;
864
865    // FIXME: volatility
866    LValue LV = CGF.EmitLValueForFieldInitialization(DestPtr, *field, 0);
867    // We never generate write-barries for initialized fields.
868    LV.setNonGC(true);
869
870    if (curInitIndex < NumInitElements) {
871      // Store the initializer into the field.
872      EmitInitializationToLValue(E->getInit(curInitIndex++), LV);
873    } else {
874      // We're out of initalizers; default-initialize to null
875      EmitNullInitializationToLValue(LV);
876    }
877
878    // Push a destructor if necessary.
879    // FIXME: if we have an array of structures, all explicitly
880    // initialized, we can end up pushing a linear number of cleanups.
881    bool pushedCleanup = false;
882    if (QualType::DestructionKind dtorKind
883          = field->getType().isDestructedType()) {
884      assert(LV.isSimple());
885      if (CGF.needsEHCleanup(dtorKind)) {
886        CGF.pushDestroy(EHCleanup, LV.getAddress(), field->getType(),
887                        CGF.getDestroyer(dtorKind), false);
888        cleanups.push_back(CGF.EHStack.stable_begin());
889        pushedCleanup = true;
890      }
891    }
892
893    // If the GEP didn't get used because of a dead zero init or something
894    // else, clean it up for -O0 builds and general tidiness.
895    if (!pushedCleanup && LV.isSimple())
896      if (llvm::GetElementPtrInst *GEP =
897            dyn_cast<llvm::GetElementPtrInst>(LV.getAddress()))
898        if (GEP->use_empty())
899          GEP->eraseFromParent();
900  }
901
902  // Deactivate all the partial cleanups in reverse order, which
903  // generally means popping them.
904  for (unsigned i = cleanups.size(); i != 0; --i)
905    CGF.DeactivateCleanupBlock(cleanups[i-1]);
906}
907
908//===----------------------------------------------------------------------===//
909//                        Entry Points into this File
910//===----------------------------------------------------------------------===//
911
912/// GetNumNonZeroBytesInInit - Get an approximate count of the number of
913/// non-zero bytes that will be stored when outputting the initializer for the
914/// specified initializer expression.
915static CharUnits GetNumNonZeroBytesInInit(const Expr *E, CodeGenFunction &CGF) {
916  E = E->IgnoreParens();
917
918  // 0 and 0.0 won't require any non-zero stores!
919  if (isSimpleZero(E, CGF)) return CharUnits::Zero();
920
921  // If this is an initlist expr, sum up the size of sizes of the (present)
922  // elements.  If this is something weird, assume the whole thing is non-zero.
923  const InitListExpr *ILE = dyn_cast<InitListExpr>(E);
924  if (ILE == 0 || !CGF.getTypes().isZeroInitializable(ILE->getType()))
925    return CGF.getContext().getTypeSizeInChars(E->getType());
926
927  // InitListExprs for structs have to be handled carefully.  If there are
928  // reference members, we need to consider the size of the reference, not the
929  // referencee.  InitListExprs for unions and arrays can't have references.
930  if (const RecordType *RT = E->getType()->getAs<RecordType>()) {
931    if (!RT->isUnionType()) {
932      RecordDecl *SD = E->getType()->getAs<RecordType>()->getDecl();
933      CharUnits NumNonZeroBytes = CharUnits::Zero();
934
935      unsigned ILEElement = 0;
936      for (RecordDecl::field_iterator Field = SD->field_begin(),
937           FieldEnd = SD->field_end(); Field != FieldEnd; ++Field) {
938        // We're done once we hit the flexible array member or run out of
939        // InitListExpr elements.
940        if (Field->getType()->isIncompleteArrayType() ||
941            ILEElement == ILE->getNumInits())
942          break;
943        if (Field->isUnnamedBitfield())
944          continue;
945
946        const Expr *E = ILE->getInit(ILEElement++);
947
948        // Reference values are always non-null and have the width of a pointer.
949        if (Field->getType()->isReferenceType())
950          NumNonZeroBytes += CGF.getContext().toCharUnitsFromBits(
951              CGF.getContext().Target.getPointerWidth(0));
952        else
953          NumNonZeroBytes += GetNumNonZeroBytesInInit(E, CGF);
954      }
955
956      return NumNonZeroBytes;
957    }
958  }
959
960
961  CharUnits NumNonZeroBytes = CharUnits::Zero();
962  for (unsigned i = 0, e = ILE->getNumInits(); i != e; ++i)
963    NumNonZeroBytes += GetNumNonZeroBytesInInit(ILE->getInit(i), CGF);
964  return NumNonZeroBytes;
965}
966
967/// CheckAggExprForMemSetUse - If the initializer is large and has a lot of
968/// zeros in it, emit a memset and avoid storing the individual zeros.
969///
970static void CheckAggExprForMemSetUse(AggValueSlot &Slot, const Expr *E,
971                                     CodeGenFunction &CGF) {
972  // If the slot is already known to be zeroed, nothing to do.  Don't mess with
973  // volatile stores.
974  if (Slot.isZeroed() || Slot.isVolatile() || Slot.getAddr() == 0) return;
975
976  // C++ objects with a user-declared constructor don't need zero'ing.
977  if (CGF.getContext().getLangOptions().CPlusPlus)
978    if (const RecordType *RT = CGF.getContext()
979                       .getBaseElementType(E->getType())->getAs<RecordType>()) {
980      const CXXRecordDecl *RD = cast<CXXRecordDecl>(RT->getDecl());
981      if (RD->hasUserDeclaredConstructor())
982        return;
983    }
984
985  // If the type is 16-bytes or smaller, prefer individual stores over memset.
986  std::pair<CharUnits, CharUnits> TypeInfo =
987    CGF.getContext().getTypeInfoInChars(E->getType());
988  if (TypeInfo.first <= CharUnits::fromQuantity(16))
989    return;
990
991  // Check to see if over 3/4 of the initializer are known to be zero.  If so,
992  // we prefer to emit memset + individual stores for the rest.
993  CharUnits NumNonZeroBytes = GetNumNonZeroBytesInInit(E, CGF);
994  if (NumNonZeroBytes*4 > TypeInfo.first)
995    return;
996
997  // Okay, it seems like a good idea to use an initial memset, emit the call.
998  llvm::Constant *SizeVal = CGF.Builder.getInt64(TypeInfo.first.getQuantity());
999  CharUnits Align = TypeInfo.second;
1000
1001  llvm::Value *Loc = Slot.getAddr();
1002  const llvm::Type *BP = llvm::Type::getInt8PtrTy(CGF.getLLVMContext());
1003
1004  Loc = CGF.Builder.CreateBitCast(Loc, BP);
1005  CGF.Builder.CreateMemSet(Loc, CGF.Builder.getInt8(0), SizeVal,
1006                           Align.getQuantity(), false);
1007
1008  // Tell the AggExprEmitter that the slot is known zero.
1009  Slot.setZeroed();
1010}
1011
1012
1013
1014
1015/// EmitAggExpr - Emit the computation of the specified expression of aggregate
1016/// type.  The result is computed into DestPtr.  Note that if DestPtr is null,
1017/// the value of the aggregate expression is not needed.  If VolatileDest is
1018/// true, DestPtr cannot be 0.
1019///
1020/// \param IsInitializer - true if this evaluation is initializing an
1021/// object whose lifetime is already being managed.
1022void CodeGenFunction::EmitAggExpr(const Expr *E, AggValueSlot Slot,
1023                                  bool IgnoreResult) {
1024  assert(E && hasAggregateLLVMType(E->getType()) &&
1025         "Invalid aggregate expression to emit");
1026  assert((Slot.getAddr() != 0 || Slot.isIgnored()) &&
1027         "slot has bits but no address");
1028
1029  // Optimize the slot if possible.
1030  CheckAggExprForMemSetUse(Slot, E, *this);
1031
1032  AggExprEmitter(*this, Slot, IgnoreResult).Visit(const_cast<Expr*>(E));
1033}
1034
1035LValue CodeGenFunction::EmitAggExprToLValue(const Expr *E) {
1036  assert(hasAggregateLLVMType(E->getType()) && "Invalid argument!");
1037  llvm::Value *Temp = CreateMemTemp(E->getType());
1038  LValue LV = MakeAddrLValue(Temp, E->getType());
1039  EmitAggExpr(E, AggValueSlot::forLValue(LV, false));
1040  return LV;
1041}
1042
1043void CodeGenFunction::EmitAggregateCopy(llvm::Value *DestPtr,
1044                                        llvm::Value *SrcPtr, QualType Ty,
1045                                        bool isVolatile) {
1046  assert(!Ty->isAnyComplexType() && "Shouldn't happen for complex");
1047
1048  if (getContext().getLangOptions().CPlusPlus) {
1049    if (const RecordType *RT = Ty->getAs<RecordType>()) {
1050      CXXRecordDecl *Record = cast<CXXRecordDecl>(RT->getDecl());
1051      assert((Record->hasTrivialCopyConstructor() ||
1052              Record->hasTrivialCopyAssignment()) &&
1053             "Trying to aggregate-copy a type without a trivial copy "
1054             "constructor or assignment operator");
1055      // Ignore empty classes in C++.
1056      if (Record->isEmpty())
1057        return;
1058    }
1059  }
1060
1061  // Aggregate assignment turns into llvm.memcpy.  This is almost valid per
1062  // C99 6.5.16.1p3, which states "If the value being stored in an object is
1063  // read from another object that overlaps in anyway the storage of the first
1064  // object, then the overlap shall be exact and the two objects shall have
1065  // qualified or unqualified versions of a compatible type."
1066  //
1067  // memcpy is not defined if the source and destination pointers are exactly
1068  // equal, but other compilers do this optimization, and almost every memcpy
1069  // implementation handles this case safely.  If there is a libc that does not
1070  // safely handle this, we can add a target hook.
1071
1072  // Get size and alignment info for this aggregate.
1073  std::pair<CharUnits, CharUnits> TypeInfo =
1074    getContext().getTypeInfoInChars(Ty);
1075
1076  // FIXME: Handle variable sized types.
1077
1078  // FIXME: If we have a volatile struct, the optimizer can remove what might
1079  // appear to be `extra' memory ops:
1080  //
1081  // volatile struct { int i; } a, b;
1082  //
1083  // int main() {
1084  //   a = b;
1085  //   a = b;
1086  // }
1087  //
1088  // we need to use a different call here.  We use isVolatile to indicate when
1089  // either the source or the destination is volatile.
1090
1091  const llvm::PointerType *DPT = cast<llvm::PointerType>(DestPtr->getType());
1092  const llvm::Type *DBP =
1093    llvm::Type::getInt8PtrTy(getLLVMContext(), DPT->getAddressSpace());
1094  DestPtr = Builder.CreateBitCast(DestPtr, DBP, "tmp");
1095
1096  const llvm::PointerType *SPT = cast<llvm::PointerType>(SrcPtr->getType());
1097  const llvm::Type *SBP =
1098    llvm::Type::getInt8PtrTy(getLLVMContext(), SPT->getAddressSpace());
1099  SrcPtr = Builder.CreateBitCast(SrcPtr, SBP, "tmp");
1100
1101  // Don't do any of the memmove_collectable tests if GC isn't set.
1102  if (CGM.getLangOptions().getGCMode() == LangOptions::NonGC) {
1103    // fall through
1104  } else if (const RecordType *RecordTy = Ty->getAs<RecordType>()) {
1105    RecordDecl *Record = RecordTy->getDecl();
1106    if (Record->hasObjectMember()) {
1107      CharUnits size = TypeInfo.first;
1108      const llvm::Type *SizeTy = ConvertType(getContext().getSizeType());
1109      llvm::Value *SizeVal = llvm::ConstantInt::get(SizeTy, size.getQuantity());
1110      CGM.getObjCRuntime().EmitGCMemmoveCollectable(*this, DestPtr, SrcPtr,
1111                                                    SizeVal);
1112      return;
1113    }
1114  } else if (Ty->isArrayType()) {
1115    QualType BaseType = getContext().getBaseElementType(Ty);
1116    if (const RecordType *RecordTy = BaseType->getAs<RecordType>()) {
1117      if (RecordTy->getDecl()->hasObjectMember()) {
1118        CharUnits size = TypeInfo.first;
1119        const llvm::Type *SizeTy = ConvertType(getContext().getSizeType());
1120        llvm::Value *SizeVal =
1121          llvm::ConstantInt::get(SizeTy, size.getQuantity());
1122        CGM.getObjCRuntime().EmitGCMemmoveCollectable(*this, DestPtr, SrcPtr,
1123                                                      SizeVal);
1124        return;
1125      }
1126    }
1127  }
1128
1129  Builder.CreateMemCpy(DestPtr, SrcPtr,
1130                       llvm::ConstantInt::get(IntPtrTy,
1131                                              TypeInfo.first.getQuantity()),
1132                       TypeInfo.second.getQuantity(), isVolatile);
1133}
1134