CGExpr.cpp revision 670a62cd1d51042ea076cda5e93f26a1d8327fb3 
1//===--- CGExpr.cpp - Emit LLVM Code from 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 Expr nodes as LLVM code.
11//
12//===----------------------------------------------------------------------===//
13
14#include "CodeGenFunction.h"
15#include "CodeGenModule.h"
16#include "CGCall.h"
17#include "CGObjCRuntime.h"
18#include "clang/AST/ASTContext.h"
19#include "clang/AST/DeclObjC.h"
20#include "llvm/Target/TargetData.h"
21using namespace clang;
22using namespace CodeGen;
23
24//===--------------------------------------------------------------------===//
25//                        Miscellaneous Helper Methods
26//===--------------------------------------------------------------------===//
27
28/// CreateTempAlloca - This creates a alloca and inserts it into the entry
29/// block.
30llvm::AllocaInst *CodeGenFunction::CreateTempAlloca(const llvm::Type *Ty,
31                                                    const char *Name) {
32  return new llvm::AllocaInst(Ty, 0, Name, AllocaInsertPt);
33}
34
35/// EvaluateExprAsBool - Perform the usual unary conversions on the specified
36/// expression and compare the result against zero, returning an Int1Ty value.
37llvm::Value *CodeGenFunction::EvaluateExprAsBool(const Expr *E) {
38  QualType BoolTy = getContext().BoolTy;
39  if (!E->getType()->isAnyComplexType())
40    return EmitScalarConversion(EmitScalarExpr(E), E->getType(), BoolTy);
41
42  return EmitComplexToScalarConversion(EmitComplexExpr(E), E->getType(),BoolTy);
43}
44
45/// EmitAnyExpr - Emit code to compute the specified expression which can have
46/// any type.  The result is returned as an RValue struct.  If this is an
47/// aggregate expression, the aggloc/agglocvolatile arguments indicate where
48/// the result should be returned.
49RValue CodeGenFunction::EmitAnyExpr(const Expr *E, llvm::Value *AggLoc,
50                                    bool isAggLocVolatile) {
51  if (!hasAggregateLLVMType(E->getType()))
52    return RValue::get(EmitScalarExpr(E));
53  else if (E->getType()->isAnyComplexType())
54    return RValue::getComplex(EmitComplexExpr(E));
55
56  EmitAggExpr(E, AggLoc, isAggLocVolatile);
57  return RValue::getAggregate(AggLoc);
58}
59
60/// EmitAnyExprToTemp - Similary to EmitAnyExpr(), however, the result
61/// will always be accessible even if no aggregate location is
62/// provided.
63RValue CodeGenFunction::EmitAnyExprToTemp(const Expr *E, llvm::Value *AggLoc,
64                                          bool isAggLocVolatile) {
65  if (!AggLoc && hasAggregateLLVMType(E->getType()) &&
66      !E->getType()->isAnyComplexType())
67    AggLoc = CreateTempAlloca(ConvertType(E->getType()), "agg.tmp");
68  return EmitAnyExpr(E, AggLoc, isAggLocVolatile);
69}
70
71/// getAccessedFieldNo - Given an encoded value and a result number, return
72/// the input field number being accessed.
73unsigned CodeGenFunction::getAccessedFieldNo(unsigned Idx,
74                                             const llvm::Constant *Elts) {
75  if (isa<llvm::ConstantAggregateZero>(Elts))
76    return 0;
77
78  return cast<llvm::ConstantInt>(Elts->getOperand(Idx))->getZExtValue();
79}
80
81
82//===----------------------------------------------------------------------===//
83//                         LValue Expression Emission
84//===----------------------------------------------------------------------===//
85
86LValue CodeGenFunction::EmitUnsupportedLValue(const Expr *E,
87                                              const char *Name) {
88  ErrorUnsupported(E, Name);
89  llvm::Type *Ty = llvm::PointerType::getUnqual(ConvertType(E->getType()));
90  return LValue::MakeAddr(llvm::UndefValue::get(Ty),
91                          E->getType().getCVRQualifiers());
92}
93
94/// EmitLValue - Emit code to compute a designator that specifies the location
95/// of the expression.
96///
97/// This can return one of two things: a simple address or a bitfield
98/// reference.  In either case, the LLVM Value* in the LValue structure is
99/// guaranteed to be an LLVM pointer type.
100///
101/// If this returns a bitfield reference, nothing about the pointee type of
102/// the LLVM value is known: For example, it may not be a pointer to an
103/// integer.
104///
105/// If this returns a normal address, and if the lvalue's C type is fixed
106/// size, this method guarantees that the returned pointer type will point to
107/// an LLVM type of the same size of the lvalue's type.  If the lvalue has a
108/// variable length type, this is not possible.
109///
110LValue CodeGenFunction::EmitLValue(const Expr *E) {
111  switch (E->getStmtClass()) {
112  default: return EmitUnsupportedLValue(E, "l-value expression");
113
114  case Expr::BinaryOperatorClass:
115    return EmitBinaryOperatorLValue(cast<BinaryOperator>(E));
116  case Expr::CallExprClass:
117  case Expr::CXXOperatorCallExprClass:
118    return EmitCallExprLValue(cast<CallExpr>(E));
119  case Expr::DeclRefExprClass: return EmitDeclRefLValue(cast<DeclRefExpr>(E));
120  case Expr::ParenExprClass:return EmitLValue(cast<ParenExpr>(E)->getSubExpr());
121  case Expr::PredefinedExprClass:
122    return EmitPredefinedLValue(cast<PredefinedExpr>(E));
123  case Expr::StringLiteralClass:
124    return EmitStringLiteralLValue(cast<StringLiteral>(E));
125
126  case Expr::CXXConditionDeclExprClass:
127    return EmitCXXConditionDeclLValue(cast<CXXConditionDeclExpr>(E));
128
129  case Expr::ObjCMessageExprClass:
130    return EmitObjCMessageExprLValue(cast<ObjCMessageExpr>(E));
131  case Expr::ObjCIvarRefExprClass:
132    return EmitObjCIvarRefLValue(cast<ObjCIvarRefExpr>(E));
133  case Expr::ObjCPropertyRefExprClass:
134    return EmitObjCPropertyRefLValue(cast<ObjCPropertyRefExpr>(E));
135  case Expr::ObjCKVCRefExprClass:
136    return EmitObjCKVCRefLValue(cast<ObjCKVCRefExpr>(E));
137  case Expr::ObjCSuperExprClass:
138    return EmitObjCSuperExpr(cast<ObjCSuperExpr>(E));
139
140  case Expr::UnaryOperatorClass:
141    return EmitUnaryOpLValue(cast<UnaryOperator>(E));
142  case Expr::ArraySubscriptExprClass:
143    return EmitArraySubscriptExpr(cast<ArraySubscriptExpr>(E));
144  case Expr::ExtVectorElementExprClass:
145    return EmitExtVectorElementExpr(cast<ExtVectorElementExpr>(E));
146  case Expr::MemberExprClass: return EmitMemberExpr(cast<MemberExpr>(E));
147  case Expr::CompoundLiteralExprClass:
148    return EmitCompoundLiteralLValue(cast<CompoundLiteralExpr>(E));
149  case Expr::ChooseExprClass:
150    // __builtin_choose_expr is the lvalue of the selected operand.
151    if (cast<ChooseExpr>(E)->isConditionTrue(getContext()))
152      return EmitLValue(cast<ChooseExpr>(E)->getLHS());
153    else
154      return EmitLValue(cast<ChooseExpr>(E)->getRHS());
155  }
156}
157
158/// EmitLoadOfLValue - Given an expression that represents a value lvalue,
159/// this method emits the address of the lvalue, then loads the result as an
160/// rvalue, returning the rvalue.
161RValue CodeGenFunction::EmitLoadOfLValue(LValue LV, QualType ExprType) {
162  if (LV.isObjCWeak()) {
163    // load of a __weak object.
164    llvm::Value *AddrWeakObj = LV.getAddress();
165    llvm::Value *read_weak = CGM.getObjCRuntime().EmitObjCWeakRead(*this,
166                                                                   AddrWeakObj);
167    return RValue::get(read_weak);
168  }
169
170  if (LV.isSimple()) {
171    llvm::Value *Ptr = LV.getAddress();
172    const llvm::Type *EltTy =
173      cast<llvm::PointerType>(Ptr->getType())->getElementType();
174
175    // Simple scalar l-value.
176    if (EltTy->isSingleValueType()) {
177      llvm::Value *V = Builder.CreateLoad(Ptr, LV.isVolatileQualified(),"tmp");
178
179      // Bool can have different representation in memory than in registers.
180      if (ExprType->isBooleanType()) {
181        if (V->getType() != llvm::Type::Int1Ty)
182          V = Builder.CreateTrunc(V, llvm::Type::Int1Ty, "tobool");
183      }
184
185      return RValue::get(V);
186    }
187
188    assert(ExprType->isFunctionType() && "Unknown scalar value");
189    return RValue::get(Ptr);
190  }
191
192  if (LV.isVectorElt()) {
193    llvm::Value *Vec = Builder.CreateLoad(LV.getVectorAddr(),
194                                          LV.isVolatileQualified(), "tmp");
195    return RValue::get(Builder.CreateExtractElement(Vec, LV.getVectorIdx(),
196                                                    "vecext"));
197  }
198
199  // If this is a reference to a subset of the elements of a vector, either
200  // shuffle the input or extract/insert them as appropriate.
201  if (LV.isExtVectorElt())
202    return EmitLoadOfExtVectorElementLValue(LV, ExprType);
203
204  if (LV.isBitfield())
205    return EmitLoadOfBitfieldLValue(LV, ExprType);
206
207  if (LV.isPropertyRef())
208    return EmitLoadOfPropertyRefLValue(LV, ExprType);
209
210  if (LV.isKVCRef())
211    return EmitLoadOfKVCRefLValue(LV, ExprType);
212
213  assert(0 && "Unknown LValue type!");
214  //an invalid RValue, but the assert will
215  //ensure that this point is never reached
216  return RValue();
217}
218
219RValue CodeGenFunction::EmitLoadOfBitfieldLValue(LValue LV,
220                                                 QualType ExprType) {
221  unsigned StartBit = LV.getBitfieldStartBit();
222  unsigned BitfieldSize = LV.getBitfieldSize();
223  llvm::Value *Ptr = LV.getBitfieldAddr();
224
225  const llvm::Type *EltTy =
226    cast<llvm::PointerType>(Ptr->getType())->getElementType();
227  unsigned EltTySize = CGM.getTargetData().getTypeSizeInBits(EltTy);
228
229  // In some cases the bitfield may straddle two memory locations.
230  // Currently we load the entire bitfield, then do the magic to
231  // sign-extend it if necessary. This results in somewhat more code
232  // than necessary for the common case (one load), since two shifts
233  // accomplish both the masking and sign extension.
234  unsigned LowBits = std::min(BitfieldSize, EltTySize - StartBit);
235  llvm::Value *Val = Builder.CreateLoad(Ptr, LV.isVolatileQualified(), "tmp");
236
237  // Shift to proper location.
238  if (StartBit)
239    Val = Builder.CreateLShr(Val, llvm::ConstantInt::get(EltTy, StartBit),
240                             "bf.lo");
241
242  // Mask off unused bits.
243  llvm::Constant *LowMask =
244    llvm::ConstantInt::get(llvm::APInt::getLowBitsSet(EltTySize, LowBits));
245  Val = Builder.CreateAnd(Val, LowMask, "bf.lo.cleared");
246
247  // Fetch the high bits if necessary.
248  if (LowBits < BitfieldSize) {
249    unsigned HighBits = BitfieldSize - LowBits;
250    llvm::Value *HighPtr =
251      Builder.CreateGEP(Ptr, llvm::ConstantInt::get(llvm::Type::Int32Ty, 1),
252                        "bf.ptr.hi");
253    llvm::Value *HighVal = Builder.CreateLoad(HighPtr,
254                                              LV.isVolatileQualified(),
255                                              "tmp");
256
257    // Mask off unused bits.
258    llvm::Constant *HighMask =
259      llvm::ConstantInt::get(llvm::APInt::getLowBitsSet(EltTySize, HighBits));
260    HighVal = Builder.CreateAnd(HighVal, HighMask, "bf.lo.cleared");
261
262    // Shift to proper location and or in to bitfield value.
263    HighVal = Builder.CreateShl(HighVal,
264                                llvm::ConstantInt::get(EltTy, LowBits));
265    Val = Builder.CreateOr(Val, HighVal, "bf.val");
266  }
267
268  // Sign extend if necessary.
269  if (LV.isBitfieldSigned()) {
270    llvm::Value *ExtraBits = llvm::ConstantInt::get(EltTy,
271                                                    EltTySize - BitfieldSize);
272    Val = Builder.CreateAShr(Builder.CreateShl(Val, ExtraBits),
273                             ExtraBits, "bf.val.sext");
274  }
275
276  // The bitfield type and the normal type differ when the storage sizes
277  // differ (currently just _Bool).
278  Val = Builder.CreateIntCast(Val, ConvertType(ExprType), false, "tmp");
279
280  return RValue::get(Val);
281}
282
283RValue CodeGenFunction::EmitLoadOfPropertyRefLValue(LValue LV,
284                                                    QualType ExprType) {
285  return EmitObjCPropertyGet(LV.getPropertyRefExpr());
286}
287
288RValue CodeGenFunction::EmitLoadOfKVCRefLValue(LValue LV,
289                                               QualType ExprType) {
290  return EmitObjCPropertyGet(LV.getKVCRefExpr());
291}
292
293// If this is a reference to a subset of the elements of a vector, either
294// shuffle the input or extract/insert them as appropriate.
295RValue CodeGenFunction::EmitLoadOfExtVectorElementLValue(LValue LV,
296                                                         QualType ExprType) {
297  llvm::Value *Vec = Builder.CreateLoad(LV.getExtVectorAddr(),
298                                        LV.isVolatileQualified(), "tmp");
299
300  const llvm::Constant *Elts = LV.getExtVectorElts();
301
302  // If the result of the expression is a non-vector type, we must be
303  // extracting a single element.  Just codegen as an extractelement.
304  const VectorType *ExprVT = ExprType->getAsVectorType();
305  if (!ExprVT) {
306    unsigned InIdx = getAccessedFieldNo(0, Elts);
307    llvm::Value *Elt = llvm::ConstantInt::get(llvm::Type::Int32Ty, InIdx);
308    return RValue::get(Builder.CreateExtractElement(Vec, Elt, "tmp"));
309  }
310
311  // If the source and destination have the same number of elements, use a
312  // vector shuffle instead of insert/extracts.
313  unsigned NumResultElts = ExprVT->getNumElements();
314  unsigned NumSourceElts =
315    cast<llvm::VectorType>(Vec->getType())->getNumElements();
316
317  if (NumResultElts == NumSourceElts) {
318    llvm::SmallVector<llvm::Constant*, 4> Mask;
319    for (unsigned i = 0; i != NumResultElts; ++i) {
320      unsigned InIdx = getAccessedFieldNo(i, Elts);
321      Mask.push_back(llvm::ConstantInt::get(llvm::Type::Int32Ty, InIdx));
322    }
323
324    llvm::Value *MaskV = llvm::ConstantVector::get(&Mask[0], Mask.size());
325    Vec = Builder.CreateShuffleVector(Vec,
326                                      llvm::UndefValue::get(Vec->getType()),
327                                      MaskV, "tmp");
328    return RValue::get(Vec);
329  }
330
331  // Start out with an undef of the result type.
332  llvm::Value *Result = llvm::UndefValue::get(ConvertType(ExprType));
333
334  // Extract/Insert each element of the result.
335  for (unsigned i = 0; i != NumResultElts; ++i) {
336    unsigned InIdx = getAccessedFieldNo(i, Elts);
337    llvm::Value *Elt = llvm::ConstantInt::get(llvm::Type::Int32Ty, InIdx);
338    Elt = Builder.CreateExtractElement(Vec, Elt, "tmp");
339
340    llvm::Value *OutIdx = llvm::ConstantInt::get(llvm::Type::Int32Ty, i);
341    Result = Builder.CreateInsertElement(Result, Elt, OutIdx, "tmp");
342  }
343
344  return RValue::get(Result);
345}
346
347
348
349/// EmitStoreThroughLValue - Store the specified rvalue into the specified
350/// lvalue, where both are guaranteed to the have the same type, and that type
351/// is 'Ty'.
352void CodeGenFunction::EmitStoreThroughLValue(RValue Src, LValue Dst,
353                                             QualType Ty) {
354  if (!Dst.isSimple()) {
355    if (Dst.isVectorElt()) {
356      // Read/modify/write the vector, inserting the new element.
357      llvm::Value *Vec = Builder.CreateLoad(Dst.getVectorAddr(),
358                                            Dst.isVolatileQualified(), "tmp");
359      Vec = Builder.CreateInsertElement(Vec, Src.getScalarVal(),
360                                        Dst.getVectorIdx(), "vecins");
361      Builder.CreateStore(Vec, Dst.getVectorAddr(),Dst.isVolatileQualified());
362      return;
363    }
364
365    // If this is an update of extended vector elements, insert them as
366    // appropriate.
367    if (Dst.isExtVectorElt())
368      return EmitStoreThroughExtVectorComponentLValue(Src, Dst, Ty);
369
370    if (Dst.isBitfield())
371      return EmitStoreThroughBitfieldLValue(Src, Dst, Ty);
372
373    if (Dst.isPropertyRef())
374      return EmitStoreThroughPropertyRefLValue(Src, Dst, Ty);
375
376    if (Dst.isKVCRef())
377      return EmitStoreThroughKVCRefLValue(Src, Dst, Ty);
378
379    assert(0 && "Unknown LValue type");
380  }
381
382  if (Dst.isObjCWeak()) {
383    // load of a __weak object.
384    llvm::Value *LvalueDst = Dst.getAddress();
385    llvm::Value *src = Src.getScalarVal();
386    CGM.getObjCRuntime().EmitObjCWeakAssign(*this, src, LvalueDst);
387    return;
388  }
389
390  if (Dst.isObjCStrong()) {
391    // load of a __strong object.
392    llvm::Value *LvalueDst = Dst.getAddress();
393    llvm::Value *src = Src.getScalarVal();
394    if (Dst.isObjCIvar())
395      CGM.getObjCRuntime().EmitObjCIvarAssign(*this, src, LvalueDst);
396    else
397      CGM.getObjCRuntime().EmitObjCGlobalAssign(*this, src, LvalueDst);
398    return;
399  }
400
401  llvm::Value *DstAddr = Dst.getAddress();
402  assert(Src.isScalar() && "Can't emit an agg store with this method");
403  // FIXME: Handle volatility etc.
404  const llvm::Type *SrcTy = Src.getScalarVal()->getType();
405  const llvm::PointerType *DstPtr = cast<llvm::PointerType>(DstAddr->getType());
406  const llvm::Type *AddrTy = DstPtr->getElementType();
407  unsigned AS = DstPtr->getAddressSpace();
408
409  if (AddrTy != SrcTy)
410    DstAddr = Builder.CreateBitCast(DstAddr,
411                                    llvm::PointerType::get(SrcTy, AS),
412                                    "storetmp");
413  Builder.CreateStore(Src.getScalarVal(), DstAddr, Dst.isVolatileQualified());
414}
415
416void CodeGenFunction::EmitStoreThroughBitfieldLValue(RValue Src, LValue Dst,
417                                                     QualType Ty,
418                                                     llvm::Value **Result) {
419  unsigned StartBit = Dst.getBitfieldStartBit();
420  unsigned BitfieldSize = Dst.getBitfieldSize();
421  llvm::Value *Ptr = Dst.getBitfieldAddr();
422
423  const llvm::Type *EltTy =
424    cast<llvm::PointerType>(Ptr->getType())->getElementType();
425  unsigned EltTySize = CGM.getTargetData().getTypeSizeInBits(EltTy);
426
427  // Get the new value, cast to the appropriate type and masked to
428  // exactly the size of the bit-field.
429  llvm::Value *SrcVal = Src.getScalarVal();
430  llvm::Value *NewVal = Builder.CreateIntCast(SrcVal, EltTy, false, "tmp");
431  llvm::Constant *Mask =
432    llvm::ConstantInt::get(llvm::APInt::getLowBitsSet(EltTySize, BitfieldSize));
433  NewVal = Builder.CreateAnd(NewVal, Mask, "bf.value");
434
435  // Return the new value of the bit-field, if requested.
436  if (Result) {
437    // Cast back to the proper type for result.
438    const llvm::Type *SrcTy = SrcVal->getType();
439    llvm::Value *SrcTrunc = Builder.CreateIntCast(NewVal, SrcTy, false,
440                                                  "bf.reload.val");
441
442    // Sign extend if necessary.
443    if (Dst.isBitfieldSigned()) {
444      unsigned SrcTySize = CGM.getTargetData().getTypeSizeInBits(SrcTy);
445      llvm::Value *ExtraBits = llvm::ConstantInt::get(SrcTy,
446                                                      SrcTySize - BitfieldSize);
447      SrcTrunc = Builder.CreateAShr(Builder.CreateShl(SrcTrunc, ExtraBits),
448                                    ExtraBits, "bf.reload.sext");
449    }
450
451    *Result = SrcTrunc;
452  }
453
454  // In some cases the bitfield may straddle two memory locations.
455  // Emit the low part first and check to see if the high needs to be
456  // done.
457  unsigned LowBits = std::min(BitfieldSize, EltTySize - StartBit);
458  llvm::Value *LowVal = Builder.CreateLoad(Ptr, Dst.isVolatileQualified(),
459                                           "bf.prev.low");
460
461  // Compute the mask for zero-ing the low part of this bitfield.
462  llvm::Constant *InvMask =
463    llvm::ConstantInt::get(~llvm::APInt::getBitsSet(EltTySize, StartBit,
464                                                    StartBit + LowBits));
465
466  // Compute the new low part as
467  //   LowVal = (LowVal & InvMask) | (NewVal << StartBit),
468  // with the shift of NewVal implicitly stripping the high bits.
469  llvm::Value *NewLowVal =
470    Builder.CreateShl(NewVal, llvm::ConstantInt::get(EltTy, StartBit),
471                      "bf.value.lo");
472  LowVal = Builder.CreateAnd(LowVal, InvMask, "bf.prev.lo.cleared");
473  LowVal = Builder.CreateOr(LowVal, NewLowVal, "bf.new.lo");
474
475  // Write back.
476  Builder.CreateStore(LowVal, Ptr, Dst.isVolatileQualified());
477
478  // If the low part doesn't cover the bitfield emit a high part.
479  if (LowBits < BitfieldSize) {
480    unsigned HighBits = BitfieldSize - LowBits;
481    llvm::Value *HighPtr =
482      Builder.CreateGEP(Ptr, llvm::ConstantInt::get(llvm::Type::Int32Ty, 1),
483                        "bf.ptr.hi");
484    llvm::Value *HighVal = Builder.CreateLoad(HighPtr,
485                                              Dst.isVolatileQualified(),
486                                              "bf.prev.hi");
487
488    // Compute the mask for zero-ing the high part of this bitfield.
489    llvm::Constant *InvMask =
490      llvm::ConstantInt::get(~llvm::APInt::getLowBitsSet(EltTySize, HighBits));
491
492    // Compute the new high part as
493    //   HighVal = (HighVal & InvMask) | (NewVal lshr LowBits),
494    // where the high bits of NewVal have already been cleared and the
495    // shift stripping the low bits.
496    llvm::Value *NewHighVal =
497      Builder.CreateLShr(NewVal, llvm::ConstantInt::get(EltTy, LowBits),
498                        "bf.value.high");
499    HighVal = Builder.CreateAnd(HighVal, InvMask, "bf.prev.hi.cleared");
500    HighVal = Builder.CreateOr(HighVal, NewHighVal, "bf.new.hi");
501
502    // Write back.
503    Builder.CreateStore(HighVal, HighPtr, Dst.isVolatileQualified());
504  }
505}
506
507void CodeGenFunction::EmitStoreThroughPropertyRefLValue(RValue Src,
508                                                        LValue Dst,
509                                                        QualType Ty) {
510  EmitObjCPropertySet(Dst.getPropertyRefExpr(), Src);
511}
512
513void CodeGenFunction::EmitStoreThroughKVCRefLValue(RValue Src,
514                                                   LValue Dst,
515                                                   QualType Ty) {
516  EmitObjCPropertySet(Dst.getKVCRefExpr(), Src);
517}
518
519void CodeGenFunction::EmitStoreThroughExtVectorComponentLValue(RValue Src,
520                                                               LValue Dst,
521                                                               QualType Ty) {
522  // This access turns into a read/modify/write of the vector.  Load the input
523  // value now.
524  llvm::Value *Vec = Builder.CreateLoad(Dst.getExtVectorAddr(),
525                                        Dst.isVolatileQualified(), "tmp");
526  const llvm::Constant *Elts = Dst.getExtVectorElts();
527
528  llvm::Value *SrcVal = Src.getScalarVal();
529
530  if (const VectorType *VTy = Ty->getAsVectorType()) {
531    unsigned NumSrcElts = VTy->getNumElements();
532
533    // Extract/Insert each element.
534    for (unsigned i = 0; i != NumSrcElts; ++i) {
535      llvm::Value *Elt = llvm::ConstantInt::get(llvm::Type::Int32Ty, i);
536      Elt = Builder.CreateExtractElement(SrcVal, Elt, "tmp");
537
538      unsigned Idx = getAccessedFieldNo(i, Elts);
539      llvm::Value *OutIdx = llvm::ConstantInt::get(llvm::Type::Int32Ty, Idx);
540      Vec = Builder.CreateInsertElement(Vec, Elt, OutIdx, "tmp");
541    }
542  } else {
543    // If the Src is a scalar (not a vector) it must be updating one element.
544    unsigned InIdx = getAccessedFieldNo(0, Elts);
545    llvm::Value *Elt = llvm::ConstantInt::get(llvm::Type::Int32Ty, InIdx);
546    Vec = Builder.CreateInsertElement(Vec, SrcVal, Elt, "tmp");
547  }
548
549  Builder.CreateStore(Vec, Dst.getExtVectorAddr(), Dst.isVolatileQualified());
550}
551
552/// SetVarDeclObjCAttribute - Set __weak/__strong attributes into the LValue
553/// object.
554static void SetVarDeclObjCAttribute(ASTContext &Ctx, const Decl *VD,
555                                    const QualType &Ty, LValue &LV)
556{
557  if (const ObjCGCAttr *A = VD->getAttr<ObjCGCAttr>()) {
558    ObjCGCAttr::GCAttrTypes attrType = A->getType();
559    LValue::SetObjCType(attrType == ObjCGCAttr::Weak,
560                        attrType == ObjCGCAttr::Strong, LV);
561  }
562  else if (Ctx.getLangOptions().ObjC1 &&
563           Ctx.getLangOptions().getGCMode() != LangOptions::NonGC) {
564    // Default behavious under objective-c's gc is for objective-c pointers
565    // be treated as though they were declared as __strong.
566    if (Ctx.isObjCObjectPointerType(Ty))
567      LValue::SetObjCType(false, true, LV);
568  }
569}
570
571LValue CodeGenFunction::EmitDeclRefLValue(const DeclRefExpr *E) {
572  const VarDecl *VD = dyn_cast<VarDecl>(E->getDecl());
573
574  if (VD && (VD->isBlockVarDecl() || isa<ParmVarDecl>(VD) ||
575        isa<ImplicitParamDecl>(VD))) {
576    LValue LV;
577    if (VD->getStorageClass() == VarDecl::Extern) {
578      LV = LValue::MakeAddr(CGM.GetAddrOfGlobalVar(VD),
579                            E->getType().getCVRQualifiers());
580    }
581    else {
582      llvm::Value *V = LocalDeclMap[VD];
583      assert(V && "BlockVarDecl not entered in LocalDeclMap?");
584      LV = LValue::MakeAddr(V, E->getType().getCVRQualifiers());
585    }
586    if (VD->isBlockVarDecl() &&
587        (VD->getStorageClass() == VarDecl::Static ||
588         VD->getStorageClass() == VarDecl::Extern))
589      SetVarDeclObjCAttribute(getContext(), VD, E->getType(), LV);
590    return LV;
591  } else if (VD && VD->isFileVarDecl()) {
592    LValue LV = LValue::MakeAddr(CGM.GetAddrOfGlobalVar(VD),
593                                 E->getType().getCVRQualifiers());
594    SetVarDeclObjCAttribute(getContext(), VD, E->getType(), LV);
595    return LV;
596  } else if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(E->getDecl())) {
597    return LValue::MakeAddr(CGM.GetAddrOfFunction(FD),
598                            E->getType().getCVRQualifiers());
599  }
600  else if (const ImplicitParamDecl *IPD =
601      dyn_cast<ImplicitParamDecl>(E->getDecl())) {
602    llvm::Value *V = LocalDeclMap[IPD];
603    assert(V && "BlockVarDecl not entered in LocalDeclMap?");
604    return LValue::MakeAddr(V, E->getType().getCVRQualifiers());
605  }
606  assert(0 && "Unimp declref");
607  //an invalid LValue, but the assert will
608  //ensure that this point is never reached.
609  return LValue();
610}
611
612LValue CodeGenFunction::EmitUnaryOpLValue(const UnaryOperator *E) {
613  // __extension__ doesn't affect lvalue-ness.
614  if (E->getOpcode() == UnaryOperator::Extension)
615    return EmitLValue(E->getSubExpr());
616
617  QualType ExprTy = getContext().getCanonicalType(E->getSubExpr()->getType());
618  switch (E->getOpcode()) {
619  default: assert(0 && "Unknown unary operator lvalue!");
620  case UnaryOperator::Deref:
621    return LValue::MakeAddr(EmitScalarExpr(E->getSubExpr()),
622                            ExprTy->getAsPointerType()->getPointeeType()
623                                    .getCVRQualifiers());
624  case UnaryOperator::Real:
625  case UnaryOperator::Imag:
626    LValue LV = EmitLValue(E->getSubExpr());
627    unsigned Idx = E->getOpcode() == UnaryOperator::Imag;
628    return LValue::MakeAddr(Builder.CreateStructGEP(LV.getAddress(),
629                                                    Idx, "idx"),
630                            ExprTy.getCVRQualifiers());
631  }
632}
633
634LValue CodeGenFunction::EmitStringLiteralLValue(const StringLiteral *E) {
635  return LValue::MakeAddr(CGM.GetAddrOfConstantStringFromLiteral(E), 0);
636}
637
638LValue CodeGenFunction::EmitPredefinedFunctionName(unsigned Type) {
639  std::string GlobalVarName;
640
641  switch (Type) {
642    default:
643      assert(0 && "Invalid type");
644    case PredefinedExpr::Func:
645      GlobalVarName = "__func__.";
646      break;
647    case PredefinedExpr::Function:
648      GlobalVarName = "__FUNCTION__.";
649      break;
650    case PredefinedExpr::PrettyFunction:
651      // FIXME:: Demangle C++ method names
652      GlobalVarName = "__PRETTY_FUNCTION__.";
653      break;
654  }
655
656  std::string FunctionName;
657  if(const FunctionDecl *FD = dyn_cast<FunctionDecl>(CurFuncDecl)) {
658    FunctionName = FD->getNameAsString();
659  } else {
660    // Just get the mangled name.
661    FunctionName = CurFn->getName();
662  }
663
664  GlobalVarName += FunctionName;
665  llvm::Constant *C =
666    CGM.GetAddrOfConstantCString(FunctionName, GlobalVarName.c_str());
667  return LValue::MakeAddr(C, 0);
668}
669
670LValue CodeGenFunction::EmitPredefinedLValue(const PredefinedExpr *E) {
671  switch (E->getIdentType()) {
672  default:
673    return EmitUnsupportedLValue(E, "predefined expression");
674  case PredefinedExpr::Func:
675  case PredefinedExpr::Function:
676  case PredefinedExpr::PrettyFunction:
677    return EmitPredefinedFunctionName(E->getIdentType());
678  }
679}
680
681LValue CodeGenFunction::EmitArraySubscriptExpr(const ArraySubscriptExpr *E) {
682  // The index must always be an integer, which is not an aggregate.  Emit it.
683  llvm::Value *Idx = EmitScalarExpr(E->getIdx());
684
685  // If the base is a vector type, then we are forming a vector element lvalue
686  // with this subscript.
687  if (E->getBase()->getType()->isVectorType()) {
688    // Emit the vector as an lvalue to get its address.
689    LValue LHS = EmitLValue(E->getBase());
690    assert(LHS.isSimple() && "Can only subscript lvalue vectors here!");
691    // FIXME: This should properly sign/zero/extend or truncate Idx to i32.
692    return LValue::MakeVectorElt(LHS.getAddress(), Idx,
693      E->getBase()->getType().getCVRQualifiers());
694  }
695
696  // The base must be a pointer, which is not an aggregate.  Emit it.
697  llvm::Value *Base = EmitScalarExpr(E->getBase());
698
699  // Extend or truncate the index type to 32 or 64-bits.
700  QualType IdxTy  = E->getIdx()->getType();
701  bool IdxSigned = IdxTy->isSignedIntegerType();
702  unsigned IdxBitwidth = cast<llvm::IntegerType>(Idx->getType())->getBitWidth();
703  if (IdxBitwidth != LLVMPointerWidth)
704    Idx = Builder.CreateIntCast(Idx, llvm::IntegerType::get(LLVMPointerWidth),
705                                IdxSigned, "idxprom");
706
707  // We know that the pointer points to a type of the correct size, unless the
708  // size is a VLA.
709  if (!E->getType()->isConstantSizeType())
710    return EmitUnsupportedLValue(E, "VLA index");
711  QualType ExprTy = getContext().getCanonicalType(E->getBase()->getType());
712
713  return LValue::MakeAddr(Builder.CreateGEP(Base, Idx, "arrayidx"),
714                          ExprTy->getAsPointerType()->getPointeeType()
715                               .getCVRQualifiers());
716}
717
718static
719llvm::Constant *GenerateConstantVector(llvm::SmallVector<unsigned, 4> &Elts) {
720  llvm::SmallVector<llvm::Constant *, 4> CElts;
721
722  for (unsigned i = 0, e = Elts.size(); i != e; ++i)
723    CElts.push_back(llvm::ConstantInt::get(llvm::Type::Int32Ty, Elts[i]));
724
725  return llvm::ConstantVector::get(&CElts[0], CElts.size());
726}
727
728LValue CodeGenFunction::
729EmitExtVectorElementExpr(const ExtVectorElementExpr *E) {
730  // Emit the base vector as an l-value.
731  LValue Base = EmitLValue(E->getBase());
732
733  // Encode the element access list into a vector of unsigned indices.
734  llvm::SmallVector<unsigned, 4> Indices;
735  E->getEncodedElementAccess(Indices);
736
737  if (Base.isSimple()) {
738    llvm::Constant *CV = GenerateConstantVector(Indices);
739    return LValue::MakeExtVectorElt(Base.getAddress(), CV,
740                                   E->getBase()->getType().getCVRQualifiers());
741  }
742  assert(Base.isExtVectorElt() && "Can only subscript lvalue vec elts here!");
743
744  llvm::Constant *BaseElts = Base.getExtVectorElts();
745  llvm::SmallVector<llvm::Constant *, 4> CElts;
746
747  for (unsigned i = 0, e = Indices.size(); i != e; ++i) {
748    if (isa<llvm::ConstantAggregateZero>(BaseElts))
749      CElts.push_back(llvm::ConstantInt::get(llvm::Type::Int32Ty, 0));
750    else
751      CElts.push_back(BaseElts->getOperand(Indices[i]));
752  }
753  llvm::Constant *CV = llvm::ConstantVector::get(&CElts[0], CElts.size());
754  return LValue::MakeExtVectorElt(Base.getExtVectorAddr(), CV,
755                                  E->getBase()->getType().getCVRQualifiers());
756}
757
758LValue CodeGenFunction::EmitMemberExpr(const MemberExpr *E) {
759  bool isUnion = false;
760  bool isIvar = false;
761  Expr *BaseExpr = E->getBase();
762  llvm::Value *BaseValue = NULL;
763  unsigned CVRQualifiers=0;
764
765  // If this is s.x, emit s as an lvalue.  If it is s->x, emit s as a scalar.
766  if (E->isArrow()) {
767    BaseValue = EmitScalarExpr(BaseExpr);
768    const PointerType *PTy =
769      cast<PointerType>(getContext().getCanonicalType(BaseExpr->getType()));
770    if (PTy->getPointeeType()->isUnionType())
771      isUnion = true;
772    CVRQualifiers = PTy->getPointeeType().getCVRQualifiers();
773  }
774  else {
775    LValue BaseLV = EmitLValue(BaseExpr);
776    if (BaseLV.isObjCIvar())
777      isIvar = true;
778    // FIXME: this isn't right for bitfields.
779    BaseValue = BaseLV.getAddress();
780    if (BaseExpr->getType()->isUnionType())
781      isUnion = true;
782    CVRQualifiers = BaseExpr->getType().getCVRQualifiers();
783  }
784
785  FieldDecl *Field = E->getMemberDecl();
786  LValue MemExpLV =  EmitLValueForField(BaseValue, Field, isUnion, CVRQualifiers);
787  LValue::SetObjCIvar(MemExpLV, isIvar);
788  return MemExpLV;
789}
790
791LValue CodeGenFunction::EmitLValueForField(llvm::Value* BaseValue,
792                                           FieldDecl* Field,
793                                           bool isUnion,
794                                           unsigned CVRQualifiers)
795{
796  llvm::Value *V;
797  unsigned idx = CGM.getTypes().getLLVMFieldNo(Field);
798
799  if (Field->isBitField()) {
800    // FIXME: CodeGenTypes should expose a method to get the appropriate
801    // type for FieldTy (the appropriate type is ABI-dependent).
802    const llvm::Type *FieldTy = CGM.getTypes().ConvertTypeForMem(Field->getType());
803    const llvm::PointerType *BaseTy =
804      cast<llvm::PointerType>(BaseValue->getType());
805    unsigned AS = BaseTy->getAddressSpace();
806    BaseValue = Builder.CreateBitCast(BaseValue,
807                                      llvm::PointerType::get(FieldTy, AS),
808                                      "tmp");
809    V = Builder.CreateGEP(BaseValue,
810                          llvm::ConstantInt::get(llvm::Type::Int32Ty, idx),
811                          "tmp");
812
813    CodeGenTypes::BitFieldInfo bitFieldInfo =
814      CGM.getTypes().getBitFieldInfo(Field);
815    return LValue::MakeBitfield(V, bitFieldInfo.Begin, bitFieldInfo.Size,
816                                Field->getType()->isSignedIntegerType(),
817                            Field->getType().getCVRQualifiers()|CVRQualifiers);
818  }
819
820  V = Builder.CreateStructGEP(BaseValue, idx, "tmp");
821
822  // Match union field type.
823  if (isUnion) {
824    const llvm::Type *FieldTy =
825      CGM.getTypes().ConvertTypeForMem(Field->getType());
826    const llvm::PointerType * BaseTy =
827      cast<llvm::PointerType>(BaseValue->getType());
828    unsigned AS = BaseTy->getAddressSpace();
829    V = Builder.CreateBitCast(V,
830                              llvm::PointerType::get(FieldTy, AS),
831                              "tmp");
832  }
833
834  LValue LV =
835    LValue::MakeAddr(V,
836                     Field->getType().getCVRQualifiers()|CVRQualifiers);
837  if (const ObjCGCAttr *A = Field->getAttr<ObjCGCAttr>()) {
838    ObjCGCAttr::GCAttrTypes attrType = A->getType();
839    // __weak attribute on a field is ignored.
840    LValue::SetObjCType(false, attrType == ObjCGCAttr::Strong, LV);
841  }
842  else if (CGM.getLangOptions().ObjC1 &&
843           CGM.getLangOptions().getGCMode() != LangOptions::NonGC) {
844    QualType ExprTy = Field->getType();
845    if (getContext().isObjCObjectPointerType(ExprTy))
846      LValue::SetObjCType(false, true, LV);
847  }
848  return LV;
849}
850
851LValue CodeGenFunction::EmitCompoundLiteralLValue(const CompoundLiteralExpr* E)
852{
853  const llvm::Type *LTy = ConvertType(E->getType());
854  llvm::Value *DeclPtr = CreateTempAlloca(LTy, ".compoundliteral");
855
856  const Expr* InitExpr = E->getInitializer();
857  LValue Result = LValue::MakeAddr(DeclPtr, E->getType().getCVRQualifiers());
858
859  if (E->getType()->isComplexType()) {
860    EmitComplexExprIntoAddr(InitExpr, DeclPtr, false);
861  } else if (hasAggregateLLVMType(E->getType())) {
862    EmitAnyExpr(InitExpr, DeclPtr, false);
863  } else {
864    EmitStoreThroughLValue(EmitAnyExpr(InitExpr), Result, E->getType());
865  }
866
867  return Result;
868}
869
870//===--------------------------------------------------------------------===//
871//                             Expression Emission
872//===--------------------------------------------------------------------===//
873
874
875RValue CodeGenFunction::EmitCallExpr(const CallExpr *E) {
876  if (const ImplicitCastExpr *IcExpr =
877      dyn_cast<const ImplicitCastExpr>(E->getCallee()))
878    if (const DeclRefExpr *DRExpr =
879        dyn_cast<const DeclRefExpr>(IcExpr->getSubExpr()))
880      if (const FunctionDecl *FDecl =
881          dyn_cast<const FunctionDecl>(DRExpr->getDecl()))
882        if (unsigned builtinID = FDecl->getIdentifier()->getBuiltinID())
883          return EmitBuiltinExpr(builtinID, E);
884
885  llvm::Value *Callee = EmitScalarExpr(E->getCallee());
886  return EmitCallExpr(Callee, E->getCallee()->getType(),
887                      E->arg_begin(), E->arg_end());
888}
889
890RValue CodeGenFunction::EmitCallExpr(Expr *FnExpr,
891                                     CallExpr::const_arg_iterator ArgBeg,
892                                     CallExpr::const_arg_iterator ArgEnd) {
893
894  llvm::Value *Callee = EmitScalarExpr(FnExpr);
895  return EmitCallExpr(Callee, FnExpr->getType(), ArgBeg, ArgEnd);
896}
897
898LValue CodeGenFunction::EmitBinaryOperatorLValue(const BinaryOperator *E) {
899  // Can only get l-value for binary operator expressions which are a
900  // simple assignment of aggregate type.
901  if (E->getOpcode() != BinaryOperator::Assign)
902    return EmitUnsupportedLValue(E, "binary l-value expression");
903
904  llvm::Value *Temp = CreateTempAlloca(ConvertType(E->getType()));
905  EmitAggExpr(E, Temp, false);
906  // FIXME: Are these qualifiers correct?
907  return LValue::MakeAddr(Temp, E->getType().getCVRQualifiers());
908}
909
910LValue CodeGenFunction::EmitCallExprLValue(const CallExpr *E) {
911  // Can only get l-value for call expression returning aggregate type
912  RValue RV = EmitCallExpr(E);
913  // FIXME: can this be volatile?
914  return LValue::MakeAddr(RV.getAggregateAddr(),
915                          E->getType().getCVRQualifiers());
916}
917
918LValue
919CodeGenFunction::EmitCXXConditionDeclLValue(const CXXConditionDeclExpr *E) {
920  EmitLocalBlockVarDecl(*E->getVarDecl());
921  return EmitDeclRefLValue(E);
922}
923
924LValue CodeGenFunction::EmitObjCMessageExprLValue(const ObjCMessageExpr *E) {
925  // Can only get l-value for message expression returning aggregate type
926  RValue RV = EmitObjCMessageExpr(E);
927  // FIXME: can this be volatile?
928  return LValue::MakeAddr(RV.getAggregateAddr(),
929                          E->getType().getCVRQualifiers());
930}
931
932llvm::Value *CodeGenFunction::EmitIvarOffset(ObjCInterfaceDecl *Interface,
933                                             const ObjCIvarDecl *Ivar) {
934  // Objective-C objects are traditionally C structures with their layout
935  // defined at compile-time.  In some implementations, their layout is not
936  // defined until run time in order to allow instance variables to be added to
937  // a class without recompiling all of the subclasses.  If this is the case
938  // then the CGObjCRuntime subclass must return true to LateBoundIvars and
939  // implement the lookup itself.
940  if (CGM.getObjCRuntime().LateBoundIVars())
941    assert(0 && "late-bound ivars are unsupported");
942
943  const llvm::Type *InterfaceLTy =
944    CGM.getTypes().ConvertType(getContext().getObjCInterfaceType(Interface));
945  const llvm::StructLayout *Layout =
946    CGM.getTargetData().getStructLayout(cast<llvm::StructType>(InterfaceLTy));
947  uint64_t Offset =
948    Layout->getElementOffset(CGM.getTypes().getLLVMFieldNo(Ivar));
949
950  return llvm::ConstantInt::get(CGM.getTypes().ConvertType(getContext().LongTy),
951                                Offset);
952}
953
954LValue CodeGenFunction::EmitLValueForIvar(llvm::Value *BaseValue,
955                                          const ObjCIvarDecl *Ivar,
956                                          unsigned CVRQualifiers) {
957  // See comment in EmitIvarOffset.
958  if (CGM.getObjCRuntime().LateBoundIVars())
959    assert(0 && "late-bound ivars are unsupported");
960
961  if (Ivar->isBitField())
962    assert(0 && "ivar bitfields are unsupported");
963
964  // TODO:  Add a special case for isa (index 0)
965  unsigned Index = CGM.getTypes().getLLVMFieldNo(Ivar);
966
967  llvm::Value *V = Builder.CreateStructGEP(BaseValue, Index, "tmp");
968  LValue LV = LValue::MakeAddr(V, Ivar->getType().getCVRQualifiers()|CVRQualifiers);
969  SetVarDeclObjCAttribute(getContext(), Ivar, Ivar->getType(), LV);
970  LValue::SetObjCIvar(LV, true);
971  return LV;
972}
973
974LValue CodeGenFunction::EmitObjCIvarRefLValue(const ObjCIvarRefExpr *E) {
975  // FIXME: A lot of the code below could be shared with EmitMemberExpr.
976  llvm::Value *BaseValue = 0;
977  const Expr *BaseExpr = E->getBase();
978  unsigned CVRQualifiers = 0;
979  if (E->isArrow()) {
980    BaseValue = EmitScalarExpr(BaseExpr);
981    const PointerType *PTy =
982      cast<PointerType>(getContext().getCanonicalType(BaseExpr->getType()));
983    CVRQualifiers = PTy->getPointeeType().getCVRQualifiers();
984  } else {
985    LValue BaseLV = EmitLValue(BaseExpr);
986    // FIXME: this isn't right for bitfields.
987    BaseValue = BaseLV.getAddress();
988    CVRQualifiers = BaseExpr->getType().getCVRQualifiers();
989  }
990
991  return EmitLValueForIvar(BaseValue, E->getDecl(), CVRQualifiers);
992}
993
994LValue
995CodeGenFunction::EmitObjCPropertyRefLValue(const ObjCPropertyRefExpr *E) {
996  // This is a special l-value that just issues sends when we load or
997  // store through it.
998  return LValue::MakePropertyRef(E, E->getType().getCVRQualifiers());
999}
1000
1001LValue
1002CodeGenFunction::EmitObjCKVCRefLValue(const ObjCKVCRefExpr *E) {
1003  // This is a special l-value that just issues sends when we load or
1004  // store through it.
1005  return LValue::MakeKVCRef(E, E->getType().getCVRQualifiers());
1006}
1007
1008LValue
1009CodeGenFunction::EmitObjCSuperExpr(const ObjCSuperExpr *E) {
1010  return EmitUnsupportedLValue(E, "use of super");
1011}
1012
1013RValue CodeGenFunction::EmitCallExpr(llvm::Value *Callee, QualType FnType,
1014                                     CallExpr::const_arg_iterator ArgBeg,
1015                                     CallExpr::const_arg_iterator ArgEnd) {
1016
1017  // The callee type will always be a pointer to function type, get the function
1018  // type.
1019  FnType = FnType->getAsPointerType()->getPointeeType();
1020  QualType ResultType = FnType->getAsFunctionType()->getResultType();
1021
1022  CallArgList Args;
1023  for (CallExpr::const_arg_iterator I = ArgBeg; I != ArgEnd; ++I)
1024    Args.push_back(std::make_pair(EmitAnyExprToTemp(*I),
1025                                  I->getType()));
1026
1027  return EmitCall(Callee, ResultType, Args);
1028}
1029