CGExpr.cpp revision 0dbe227feccf6a8dbadfff8ca3f80416b7bf2f28 
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/// getAccessedFieldNo - Given an encoded value and a result number, return
61/// the input field number being accessed.
62unsigned CodeGenFunction::getAccessedFieldNo(unsigned Idx,
63                                             const llvm::Constant *Elts) {
64  if (isa<llvm::ConstantAggregateZero>(Elts))
65    return 0;
66
67  return cast<llvm::ConstantInt>(Elts->getOperand(Idx))->getZExtValue();
68}
69
70
71//===----------------------------------------------------------------------===//
72//                         LValue Expression Emission
73//===----------------------------------------------------------------------===//
74
75LValue CodeGenFunction::EmitUnsupportedLValue(const Expr *E,
76                                              const char *Name) {
77  ErrorUnsupported(E, Name);
78  llvm::Type *Ty = llvm::PointerType::getUnqual(ConvertType(E->getType()));
79  return LValue::MakeAddr(llvm::UndefValue::get(Ty),
80                          E->getType().getCVRQualifiers());
81}
82
83/// EmitLValue - Emit code to compute a designator that specifies the location
84/// of the expression.
85///
86/// This can return one of two things: a simple address or a bitfield
87/// reference.  In either case, the LLVM Value* in the LValue structure is
88/// guaranteed to be an LLVM pointer type.
89///
90/// If this returns a bitfield reference, nothing about the pointee type of
91/// the LLVM value is known: For example, it may not be a pointer to an
92/// integer.
93///
94/// If this returns a normal address, and if the lvalue's C type is fixed
95/// size, this method guarantees that the returned pointer type will point to
96/// an LLVM type of the same size of the lvalue's type.  If the lvalue has a
97/// variable length type, this is not possible.
98///
99LValue CodeGenFunction::EmitLValue(const Expr *E) {
100  switch (E->getStmtClass()) {
101  default: return EmitUnsupportedLValue(E, "l-value expression");
102
103  case Expr::BinaryOperatorClass:
104    return EmitBinaryOperatorLValue(cast<BinaryOperator>(E));
105  case Expr::CallExprClass: return EmitCallExprLValue(cast<CallExpr>(E));
106  case Expr::DeclRefExprClass: return EmitDeclRefLValue(cast<DeclRefExpr>(E));
107  case Expr::ParenExprClass:return EmitLValue(cast<ParenExpr>(E)->getSubExpr());
108  case Expr::PredefinedExprClass:
109    return EmitPredefinedLValue(cast<PredefinedExpr>(E));
110  case Expr::StringLiteralClass:
111    return EmitStringLiteralLValue(cast<StringLiteral>(E));
112
113  case Expr::ObjCMessageExprClass:
114    return EmitObjCMessageExprLValue(cast<ObjCMessageExpr>(E));
115  case Expr::ObjCIvarRefExprClass:
116    return EmitObjCIvarRefLValue(cast<ObjCIvarRefExpr>(E));
117  case Expr::ObjCPropertyRefExprClass:
118    return EmitObjCPropertyRefLValue(cast<ObjCPropertyRefExpr>(E));
119
120  case Expr::UnaryOperatorClass:
121    return EmitUnaryOpLValue(cast<UnaryOperator>(E));
122  case Expr::ArraySubscriptExprClass:
123    return EmitArraySubscriptExpr(cast<ArraySubscriptExpr>(E));
124  case Expr::ExtVectorElementExprClass:
125    return EmitExtVectorElementExpr(cast<ExtVectorElementExpr>(E));
126  case Expr::MemberExprClass: return EmitMemberExpr(cast<MemberExpr>(E));
127  case Expr::CompoundLiteralExprClass:
128    return EmitCompoundLiteralLValue(cast<CompoundLiteralExpr>(E));
129  }
130}
131
132/// EmitLoadOfLValue - Given an expression that represents a value lvalue,
133/// this method emits the address of the lvalue, then loads the result as an
134/// rvalue, returning the rvalue.
135RValue CodeGenFunction::EmitLoadOfLValue(LValue LV, QualType ExprType) {
136  if (LV.isSimple()) {
137    llvm::Value *Ptr = LV.getAddress();
138    const llvm::Type *EltTy =
139      cast<llvm::PointerType>(Ptr->getType())->getElementType();
140
141    // Simple scalar l-value.
142    if (EltTy->isSingleValueType()) {
143      llvm::Value *V = Builder.CreateLoad(Ptr, LV.isVolatileQualified(),"tmp");
144
145      // Bool can have different representation in memory than in registers.
146      if (ExprType->isBooleanType()) {
147        if (V->getType() != llvm::Type::Int1Ty)
148          V = Builder.CreateTrunc(V, llvm::Type::Int1Ty, "tobool");
149      }
150
151      return RValue::get(V);
152    }
153
154    assert(ExprType->isFunctionType() && "Unknown scalar value");
155    return RValue::get(Ptr);
156  }
157
158  if (LV.isVectorElt()) {
159    llvm::Value *Vec = Builder.CreateLoad(LV.getVectorAddr(),
160                                          LV.isVolatileQualified(), "tmp");
161    return RValue::get(Builder.CreateExtractElement(Vec, LV.getVectorIdx(),
162                                                    "vecext"));
163  }
164
165  // If this is a reference to a subset of the elements of a vector, either
166  // shuffle the input or extract/insert them as appropriate.
167  if (LV.isExtVectorElt())
168    return EmitLoadOfExtVectorElementLValue(LV, ExprType);
169
170  if (LV.isBitfield())
171    return EmitLoadOfBitfieldLValue(LV, ExprType);
172
173  if (LV.isPropertyRef())
174    return EmitLoadOfPropertyRefLValue(LV, ExprType);
175
176  assert(0 && "Unknown LValue type!");
177  //an invalid RValue, but the assert will
178  //ensure that this point is never reached
179  return RValue();
180}
181
182RValue CodeGenFunction::EmitLoadOfBitfieldLValue(LValue LV,
183                                                 QualType ExprType) {
184  unsigned StartBit = LV.getBitfieldStartBit();
185  unsigned BitfieldSize = LV.getBitfieldSize();
186  llvm::Value *Ptr = LV.getBitfieldAddr();
187
188  const llvm::Type *EltTy =
189    cast<llvm::PointerType>(Ptr->getType())->getElementType();
190  unsigned EltTySize = CGM.getTargetData().getTypeSizeInBits(EltTy);
191
192  // In some cases the bitfield may straddle two memory locations.
193  // Currently we load the entire bitfield, then do the magic to
194  // sign-extend it if necessary. This results in somewhat more code
195  // than necessary for the common case (one load), since two shifts
196  // accomplish both the masking and sign extension.
197  unsigned LowBits = std::min(BitfieldSize, EltTySize - StartBit);
198  llvm::Value *Val = Builder.CreateLoad(Ptr, LV.isVolatileQualified(), "tmp");
199
200  // Shift to proper location.
201  Val = Builder.CreateLShr(Val, llvm::ConstantInt::get(EltTy, StartBit),
202                           "bf.lo");
203
204  // Mask off unused bits.
205  llvm::Constant *LowMask =
206    llvm::ConstantInt::get(llvm::APInt::getLowBitsSet(EltTySize, LowBits));
207  Val = Builder.CreateAnd(Val, LowMask, "bf.lo.cleared");
208
209  // Fetch the high bits if necessary.
210  if (LowBits < BitfieldSize) {
211    unsigned HighBits = BitfieldSize - LowBits;
212    llvm::Value *HighPtr =
213      Builder.CreateGEP(Ptr, llvm::ConstantInt::get(llvm::Type::Int32Ty, 1),
214                        "bf.ptr.hi");
215    llvm::Value *HighVal = Builder.CreateLoad(HighPtr,
216                                              LV.isVolatileQualified(),
217                                              "tmp");
218
219    // Mask off unused bits.
220    llvm::Constant *HighMask =
221      llvm::ConstantInt::get(llvm::APInt::getLowBitsSet(EltTySize, HighBits));
222    HighVal = Builder.CreateAnd(HighVal, HighMask, "bf.lo.cleared");
223
224    // Shift to proper location and or in to bitfield value.
225    HighVal = Builder.CreateShl(HighVal,
226                                llvm::ConstantInt::get(EltTy, LowBits));
227    Val = Builder.CreateOr(Val, HighVal, "bf.val");
228  }
229
230  // Sign extend if necessary.
231  if (LV.isBitfieldSigned()) {
232    llvm::Value *ExtraBits = llvm::ConstantInt::get(EltTy,
233                                                    EltTySize - BitfieldSize);
234    Val = Builder.CreateAShr(Builder.CreateShl(Val, ExtraBits),
235                             ExtraBits, "bf.val.sext");
236  }
237
238  // The bitfield type and the normal type differ when the storage sizes
239  // differ (currently just _Bool).
240  Val = Builder.CreateIntCast(Val, ConvertType(ExprType), false, "tmp");
241
242  return RValue::get(Val);
243}
244
245RValue CodeGenFunction::EmitLoadOfPropertyRefLValue(LValue LV,
246                                                    QualType ExprType) {
247  return EmitObjCPropertyGet(LV.getPropertyRefExpr());
248}
249
250// If this is a reference to a subset of the elements of a vector, either
251// shuffle the input or extract/insert them as appropriate.
252RValue CodeGenFunction::EmitLoadOfExtVectorElementLValue(LValue LV,
253                                                         QualType ExprType) {
254  llvm::Value *Vec = Builder.CreateLoad(LV.getExtVectorAddr(),
255                                        LV.isVolatileQualified(), "tmp");
256
257  const llvm::Constant *Elts = LV.getExtVectorElts();
258
259  // If the result of the expression is a non-vector type, we must be
260  // extracting a single element.  Just codegen as an extractelement.
261  const VectorType *ExprVT = ExprType->getAsVectorType();
262  if (!ExprVT) {
263    unsigned InIdx = getAccessedFieldNo(0, Elts);
264    llvm::Value *Elt = llvm::ConstantInt::get(llvm::Type::Int32Ty, InIdx);
265    return RValue::get(Builder.CreateExtractElement(Vec, Elt, "tmp"));
266  }
267
268  // If the source and destination have the same number of elements, use a
269  // vector shuffle instead of insert/extracts.
270  unsigned NumResultElts = ExprVT->getNumElements();
271  unsigned NumSourceElts =
272    cast<llvm::VectorType>(Vec->getType())->getNumElements();
273
274  if (NumResultElts == NumSourceElts) {
275    llvm::SmallVector<llvm::Constant*, 4> Mask;
276    for (unsigned i = 0; i != NumResultElts; ++i) {
277      unsigned InIdx = getAccessedFieldNo(i, Elts);
278      Mask.push_back(llvm::ConstantInt::get(llvm::Type::Int32Ty, InIdx));
279    }
280
281    llvm::Value *MaskV = llvm::ConstantVector::get(&Mask[0], Mask.size());
282    Vec = Builder.CreateShuffleVector(Vec,
283                                      llvm::UndefValue::get(Vec->getType()),
284                                      MaskV, "tmp");
285    return RValue::get(Vec);
286  }
287
288  // Start out with an undef of the result type.
289  llvm::Value *Result = llvm::UndefValue::get(ConvertType(ExprType));
290
291  // Extract/Insert each element of the result.
292  for (unsigned i = 0; i != NumResultElts; ++i) {
293    unsigned InIdx = getAccessedFieldNo(i, Elts);
294    llvm::Value *Elt = llvm::ConstantInt::get(llvm::Type::Int32Ty, InIdx);
295    Elt = Builder.CreateExtractElement(Vec, Elt, "tmp");
296
297    llvm::Value *OutIdx = llvm::ConstantInt::get(llvm::Type::Int32Ty, i);
298    Result = Builder.CreateInsertElement(Result, Elt, OutIdx, "tmp");
299  }
300
301  return RValue::get(Result);
302}
303
304
305
306/// EmitStoreThroughLValue - Store the specified rvalue into the specified
307/// lvalue, where both are guaranteed to the have the same type, and that type
308/// is 'Ty'.
309void CodeGenFunction::EmitStoreThroughLValue(RValue Src, LValue Dst,
310                                             QualType Ty) {
311  if (!Dst.isSimple()) {
312    if (Dst.isVectorElt()) {
313      // Read/modify/write the vector, inserting the new element.
314      llvm::Value *Vec = Builder.CreateLoad(Dst.getVectorAddr(),
315                                            Dst.isVolatileQualified(), "tmp");
316      Vec = Builder.CreateInsertElement(Vec, Src.getScalarVal(),
317                                        Dst.getVectorIdx(), "vecins");
318      Builder.CreateStore(Vec, Dst.getVectorAddr(),Dst.isVolatileQualified());
319      return;
320    }
321
322    // If this is an update of extended vector elements, insert them as
323    // appropriate.
324    if (Dst.isExtVectorElt())
325      return EmitStoreThroughExtVectorComponentLValue(Src, Dst, Ty);
326
327    if (Dst.isBitfield())
328      return EmitStoreThroughBitfieldLValue(Src, Dst, Ty);
329
330    if (Dst.isPropertyRef())
331      return EmitStoreThroughPropertyRefLValue(Src, Dst, Ty);
332
333    assert(0 && "Unknown LValue type");
334  }
335
336  llvm::Value *DstAddr = Dst.getAddress();
337  assert(Src.isScalar() && "Can't emit an agg store with this method");
338  // FIXME: Handle volatility etc.
339  const llvm::Type *SrcTy = Src.getScalarVal()->getType();
340  const llvm::PointerType *DstPtr = cast<llvm::PointerType>(DstAddr->getType());
341  const llvm::Type *AddrTy = DstPtr->getElementType();
342  unsigned AS = DstPtr->getAddressSpace();
343
344  if (AddrTy != SrcTy)
345    DstAddr = Builder.CreateBitCast(DstAddr,
346                                    llvm::PointerType::get(SrcTy, AS),
347                                    "storetmp");
348  Builder.CreateStore(Src.getScalarVal(), DstAddr, Dst.isVolatileQualified());
349}
350
351void CodeGenFunction::EmitStoreThroughBitfieldLValue(RValue Src, LValue Dst,
352                                                     QualType Ty) {
353  unsigned StartBit = Dst.getBitfieldStartBit();
354  unsigned BitfieldSize = Dst.getBitfieldSize();
355  llvm::Value *Ptr = Dst.getBitfieldAddr();
356
357  const llvm::Type *EltTy =
358    cast<llvm::PointerType>(Ptr->getType())->getElementType();
359  unsigned EltTySize = CGM.getTargetData().getTypeSizeInBits(EltTy);
360
361  // Get the new value, cast to the appropriate type and masked to
362  // exactly the size of the bit-field.
363  llvm::Value *NewVal = Src.getScalarVal();
364  NewVal = Builder.CreateIntCast(NewVal, EltTy, false, "tmp");
365  llvm::Constant *Mask =
366    llvm::ConstantInt::get(llvm::APInt::getLowBitsSet(EltTySize, BitfieldSize));
367  NewVal = Builder.CreateAnd(NewVal, Mask, "bf.value");
368
369  // In some cases the bitfield may straddle two memory locations.
370  // Emit the low part first and check to see if the high needs to be
371  // done.
372  unsigned LowBits = std::min(BitfieldSize, EltTySize - StartBit);
373  llvm::Value *LowVal = Builder.CreateLoad(Ptr, Dst.isVolatileQualified(),
374                                           "bf.prev.low");
375
376  // Compute the mask for zero-ing the low part of this bitfield.
377  llvm::Constant *InvMask =
378    llvm::ConstantInt::get(~llvm::APInt::getBitsSet(EltTySize, StartBit,
379                                                    StartBit + LowBits));
380
381  // Compute the new low part as
382  //   LowVal = (LowVal & InvMask) | (NewVal << StartBit),
383  // with the shift of NewVal implicitly stripping the high bits.
384  llvm::Value *NewLowVal =
385    Builder.CreateShl(NewVal, llvm::ConstantInt::get(EltTy, StartBit),
386                      "bf.value.lo");
387  LowVal = Builder.CreateAnd(LowVal, InvMask, "bf.prev.lo.cleared");
388  LowVal = Builder.CreateOr(LowVal, NewLowVal, "bf.new.lo");
389
390  // Write back.
391  Builder.CreateStore(LowVal, Ptr, Dst.isVolatileQualified());
392
393  // If the low part doesn't cover the bitfield emit a high part.
394  if (LowBits < BitfieldSize) {
395    unsigned HighBits = BitfieldSize - LowBits;
396    llvm::Value *HighPtr =
397      Builder.CreateGEP(Ptr, llvm::ConstantInt::get(llvm::Type::Int32Ty, 1),
398                        "bf.ptr.hi");
399    llvm::Value *HighVal = Builder.CreateLoad(HighPtr,
400                                              Dst.isVolatileQualified(),
401                                              "bf.prev.hi");
402
403    // Compute the mask for zero-ing the high part of this bitfield.
404    llvm::Constant *InvMask =
405      llvm::ConstantInt::get(~llvm::APInt::getLowBitsSet(EltTySize, HighBits));
406
407    // Compute the new high part as
408    //   HighVal = (HighVal & InvMask) | (NewVal lshr LowBits),
409    // where the high bits of NewVal have already been cleared and the
410    // shift stripping the low bits.
411    llvm::Value *NewHighVal =
412      Builder.CreateLShr(NewVal, llvm::ConstantInt::get(EltTy, LowBits),
413                        "bf.value.high");
414    HighVal = Builder.CreateAnd(HighVal, InvMask, "bf.prev.hi.cleared");
415    HighVal = Builder.CreateOr(HighVal, NewHighVal, "bf.new.hi");
416
417    // Write back.
418    Builder.CreateStore(HighVal, HighPtr, Dst.isVolatileQualified());
419  }
420}
421
422void CodeGenFunction::EmitStoreThroughPropertyRefLValue(RValue Src,
423                                                        LValue Dst,
424                                                        QualType Ty) {
425  EmitObjCPropertySet(Dst.getPropertyRefExpr(), Src);
426}
427
428void CodeGenFunction::EmitStoreThroughExtVectorComponentLValue(RValue Src,
429                                                               LValue Dst,
430                                                               QualType Ty) {
431  // This access turns into a read/modify/write of the vector.  Load the input
432  // value now.
433  llvm::Value *Vec = Builder.CreateLoad(Dst.getExtVectorAddr(),
434                                        Dst.isVolatileQualified(), "tmp");
435  const llvm::Constant *Elts = Dst.getExtVectorElts();
436
437  llvm::Value *SrcVal = Src.getScalarVal();
438
439  if (const VectorType *VTy = Ty->getAsVectorType()) {
440    unsigned NumSrcElts = VTy->getNumElements();
441
442    // Extract/Insert each element.
443    for (unsigned i = 0; i != NumSrcElts; ++i) {
444      llvm::Value *Elt = llvm::ConstantInt::get(llvm::Type::Int32Ty, i);
445      Elt = Builder.CreateExtractElement(SrcVal, Elt, "tmp");
446
447      unsigned Idx = getAccessedFieldNo(i, Elts);
448      llvm::Value *OutIdx = llvm::ConstantInt::get(llvm::Type::Int32Ty, Idx);
449      Vec = Builder.CreateInsertElement(Vec, Elt, OutIdx, "tmp");
450    }
451  } else {
452    // If the Src is a scalar (not a vector) it must be updating one element.
453    unsigned InIdx = getAccessedFieldNo(0, Elts);
454    llvm::Value *Elt = llvm::ConstantInt::get(llvm::Type::Int32Ty, InIdx);
455    Vec = Builder.CreateInsertElement(Vec, SrcVal, Elt, "tmp");
456  }
457
458  Builder.CreateStore(Vec, Dst.getExtVectorAddr(), Dst.isVolatileQualified());
459}
460
461
462LValue CodeGenFunction::EmitDeclRefLValue(const DeclRefExpr *E) {
463  const VarDecl *VD = dyn_cast<VarDecl>(E->getDecl());
464
465  if (VD && (VD->isBlockVarDecl() || isa<ParmVarDecl>(VD) ||
466        isa<ImplicitParamDecl>(VD))) {
467    if (VD->getStorageClass() == VarDecl::Extern)
468      return LValue::MakeAddr(CGM.GetAddrOfGlobalVar(VD),
469                              E->getType().getCVRQualifiers());
470    else {
471      llvm::Value *V = LocalDeclMap[VD];
472      assert(V && "BlockVarDecl not entered in LocalDeclMap?");
473      return LValue::MakeAddr(V, E->getType().getCVRQualifiers());
474    }
475  } else if (VD && VD->isFileVarDecl()) {
476    return LValue::MakeAddr(CGM.GetAddrOfGlobalVar(VD),
477                            E->getType().getCVRQualifiers());
478  } else if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(E->getDecl())) {
479    return LValue::MakeAddr(CGM.GetAddrOfFunction(FD),
480                            E->getType().getCVRQualifiers());
481  }
482  else if (const ImplicitParamDecl *IPD =
483      dyn_cast<ImplicitParamDecl>(E->getDecl())) {
484    llvm::Value *V = LocalDeclMap[IPD];
485    assert(V && "BlockVarDecl not entered in LocalDeclMap?");
486    return LValue::MakeAddr(V, E->getType().getCVRQualifiers());
487  }
488  assert(0 && "Unimp declref");
489  //an invalid LValue, but the assert will
490  //ensure that this point is never reached.
491  return LValue();
492}
493
494LValue CodeGenFunction::EmitUnaryOpLValue(const UnaryOperator *E) {
495  // __extension__ doesn't affect lvalue-ness.
496  if (E->getOpcode() == UnaryOperator::Extension)
497    return EmitLValue(E->getSubExpr());
498
499  QualType ExprTy = getContext().getCanonicalType(E->getSubExpr()->getType());
500  switch (E->getOpcode()) {
501  default: assert(0 && "Unknown unary operator lvalue!");
502  case UnaryOperator::Deref:
503    return LValue::MakeAddr(EmitScalarExpr(E->getSubExpr()),
504                            ExprTy->getAsPointerType()->getPointeeType()
505                                    .getCVRQualifiers());
506  case UnaryOperator::Real:
507  case UnaryOperator::Imag:
508    LValue LV = EmitLValue(E->getSubExpr());
509    unsigned Idx = E->getOpcode() == UnaryOperator::Imag;
510    return LValue::MakeAddr(Builder.CreateStructGEP(LV.getAddress(),
511                                                    Idx, "idx"),
512                            ExprTy.getCVRQualifiers());
513  }
514}
515
516LValue CodeGenFunction::EmitStringLiteralLValue(const StringLiteral *E) {
517  return LValue::MakeAddr(CGM.GetAddrOfConstantStringFromLiteral(E), 0);
518}
519
520LValue CodeGenFunction::EmitPredefinedLValue(const PredefinedExpr *E) {
521  std::string FunctionName;
522  if(const FunctionDecl *FD = dyn_cast<FunctionDecl>(CurFuncDecl)) {
523    FunctionName = FD->getName();
524  } else if (isa<ObjCMethodDecl>(CurFuncDecl)) {
525    // Just get the mangled name.
526    FunctionName  = CurFn->getName();
527  } else {
528    return EmitUnsupportedLValue(E, "predefined expression");
529  }
530  std::string GlobalVarName;
531
532  switch (E->getIdentType()) {
533    default:
534      return EmitUnsupportedLValue(E, "predefined expression");
535    case PredefinedExpr::Func:
536      GlobalVarName = "__func__.";
537      break;
538    case PredefinedExpr::Function:
539      GlobalVarName = "__FUNCTION__.";
540      break;
541    case PredefinedExpr::PrettyFunction:
542      // FIXME:: Demangle C++ method names
543      GlobalVarName = "__PRETTY_FUNCTION__.";
544      break;
545  }
546
547  GlobalVarName += FunctionName;
548
549  // FIXME: Can cache/reuse these within the module.
550  llvm::Constant *C = llvm::ConstantArray::get(FunctionName);
551
552  // Create a global variable for this.
553  C = new llvm::GlobalVariable(C->getType(), true,
554                               llvm::GlobalValue::InternalLinkage,
555                               C, GlobalVarName, CurFn->getParent());
556  return LValue::MakeAddr(C,0);
557}
558
559LValue CodeGenFunction::EmitArraySubscriptExpr(const ArraySubscriptExpr *E) {
560  // The index must always be an integer, which is not an aggregate.  Emit it.
561  llvm::Value *Idx = EmitScalarExpr(E->getIdx());
562
563  // If the base is a vector type, then we are forming a vector element lvalue
564  // with this subscript.
565  if (E->getBase()->getType()->isVectorType()) {
566    // Emit the vector as an lvalue to get its address.
567    LValue LHS = EmitLValue(E->getBase());
568    assert(LHS.isSimple() && "Can only subscript lvalue vectors here!");
569    // FIXME: This should properly sign/zero/extend or truncate Idx to i32.
570    return LValue::MakeVectorElt(LHS.getAddress(), Idx,
571      E->getBase()->getType().getCVRQualifiers());
572  }
573
574  // The base must be a pointer, which is not an aggregate.  Emit it.
575  llvm::Value *Base = EmitScalarExpr(E->getBase());
576
577  // Extend or truncate the index type to 32 or 64-bits.
578  QualType IdxTy  = E->getIdx()->getType();
579  bool IdxSigned = IdxTy->isSignedIntegerType();
580  unsigned IdxBitwidth = cast<llvm::IntegerType>(Idx->getType())->getBitWidth();
581  if (IdxBitwidth != LLVMPointerWidth)
582    Idx = Builder.CreateIntCast(Idx, llvm::IntegerType::get(LLVMPointerWidth),
583                                IdxSigned, "idxprom");
584
585  // We know that the pointer points to a type of the correct size, unless the
586  // size is a VLA.
587  if (!E->getType()->isConstantSizeType())
588    return EmitUnsupportedLValue(E, "VLA index");
589  QualType ExprTy = getContext().getCanonicalType(E->getBase()->getType());
590
591  return LValue::MakeAddr(Builder.CreateGEP(Base, Idx, "arrayidx"),
592                          ExprTy->getAsPointerType()->getPointeeType()
593                               .getCVRQualifiers());
594}
595
596static
597llvm::Constant *GenerateConstantVector(llvm::SmallVector<unsigned, 4> &Elts) {
598  llvm::SmallVector<llvm::Constant *, 4> CElts;
599
600  for (unsigned i = 0, e = Elts.size(); i != e; ++i)
601    CElts.push_back(llvm::ConstantInt::get(llvm::Type::Int32Ty, Elts[i]));
602
603  return llvm::ConstantVector::get(&CElts[0], CElts.size());
604}
605
606LValue CodeGenFunction::
607EmitExtVectorElementExpr(const ExtVectorElementExpr *E) {
608  // Emit the base vector as an l-value.
609  LValue Base = EmitLValue(E->getBase());
610
611  // Encode the element access list into a vector of unsigned indices.
612  llvm::SmallVector<unsigned, 4> Indices;
613  E->getEncodedElementAccess(Indices);
614
615  if (Base.isSimple()) {
616    llvm::Constant *CV = GenerateConstantVector(Indices);
617    return LValue::MakeExtVectorElt(Base.getAddress(), CV,
618                                   E->getBase()->getType().getCVRQualifiers());
619  }
620  assert(Base.isExtVectorElt() && "Can only subscript lvalue vec elts here!");
621
622  llvm::Constant *BaseElts = Base.getExtVectorElts();
623  llvm::SmallVector<llvm::Constant *, 4> CElts;
624
625  for (unsigned i = 0, e = Indices.size(); i != e; ++i) {
626    if (isa<llvm::ConstantAggregateZero>(BaseElts))
627      CElts.push_back(llvm::ConstantInt::get(llvm::Type::Int32Ty, 0));
628    else
629      CElts.push_back(BaseElts->getOperand(Indices[i]));
630  }
631  llvm::Constant *CV = llvm::ConstantVector::get(&CElts[0], CElts.size());
632  return LValue::MakeExtVectorElt(Base.getExtVectorAddr(), CV,
633                                  E->getBase()->getType().getCVRQualifiers());
634}
635
636LValue CodeGenFunction::EmitMemberExpr(const MemberExpr *E) {
637  bool isUnion = false;
638  Expr *BaseExpr = E->getBase();
639  llvm::Value *BaseValue = NULL;
640  unsigned CVRQualifiers=0;
641
642  // If this is s.x, emit s as an lvalue.  If it is s->x, emit s as a scalar.
643  if (E->isArrow()) {
644    BaseValue = EmitScalarExpr(BaseExpr);
645    const PointerType *PTy =
646      cast<PointerType>(getContext().getCanonicalType(BaseExpr->getType()));
647    if (PTy->getPointeeType()->isUnionType())
648      isUnion = true;
649    CVRQualifiers = PTy->getPointeeType().getCVRQualifiers();
650  }
651  else {
652    LValue BaseLV = EmitLValue(BaseExpr);
653    // FIXME: this isn't right for bitfields.
654    BaseValue = BaseLV.getAddress();
655    if (BaseExpr->getType()->isUnionType())
656      isUnion = true;
657    CVRQualifiers = BaseExpr->getType().getCVRQualifiers();
658  }
659
660  FieldDecl *Field = E->getMemberDecl();
661  return EmitLValueForField(BaseValue, Field, isUnion, CVRQualifiers);
662}
663
664LValue CodeGenFunction::EmitLValueForField(llvm::Value* BaseValue,
665                                           FieldDecl* Field,
666                                           bool isUnion,
667                                           unsigned CVRQualifiers)
668{
669  llvm::Value *V;
670  unsigned idx = CGM.getTypes().getLLVMFieldNo(Field);
671
672  if (Field->isBitField()) {
673    // FIXME: CodeGenTypes should expose a method to get the appropriate
674    // type for FieldTy (the appropriate type is ABI-dependent).
675    const llvm::Type *FieldTy = CGM.getTypes().ConvertTypeForMem(Field->getType());
676    const llvm::PointerType *BaseTy =
677      cast<llvm::PointerType>(BaseValue->getType());
678    unsigned AS = BaseTy->getAddressSpace();
679    BaseValue = Builder.CreateBitCast(BaseValue,
680                                      llvm::PointerType::get(FieldTy, AS),
681                                      "tmp");
682    V = Builder.CreateGEP(BaseValue,
683                          llvm::ConstantInt::get(llvm::Type::Int32Ty, idx),
684                          "tmp");
685
686    CodeGenTypes::BitFieldInfo bitFieldInfo =
687      CGM.getTypes().getBitFieldInfo(Field);
688    return LValue::MakeBitfield(V, bitFieldInfo.Begin, bitFieldInfo.Size,
689                                Field->getType()->isSignedIntegerType(),
690                            Field->getType().getCVRQualifiers()|CVRQualifiers);
691  }
692
693  V = Builder.CreateStructGEP(BaseValue, idx, "tmp");
694
695  // Match union field type.
696  if (isUnion) {
697    const llvm::Type *FieldTy =
698      CGM.getTypes().ConvertTypeForMem(Field->getType());
699    const llvm::PointerType * BaseTy =
700      cast<llvm::PointerType>(BaseValue->getType());
701    unsigned AS = BaseTy->getAddressSpace();
702    V = Builder.CreateBitCast(V,
703                              llvm::PointerType::get(FieldTy, AS),
704                              "tmp");
705  }
706
707  return LValue::MakeAddr(V,
708                          Field->getType().getCVRQualifiers()|CVRQualifiers);
709}
710
711LValue CodeGenFunction::EmitCompoundLiteralLValue(const CompoundLiteralExpr* E)
712{
713  const llvm::Type *LTy = ConvertType(E->getType());
714  llvm::Value *DeclPtr = CreateTempAlloca(LTy, ".compoundliteral");
715
716  const Expr* InitExpr = E->getInitializer();
717  LValue Result = LValue::MakeAddr(DeclPtr, E->getType().getCVRQualifiers());
718
719  if (E->getType()->isComplexType()) {
720    EmitComplexExprIntoAddr(InitExpr, DeclPtr, false);
721  } else if (hasAggregateLLVMType(E->getType())) {
722    EmitAnyExpr(InitExpr, DeclPtr, false);
723  } else {
724    EmitStoreThroughLValue(EmitAnyExpr(InitExpr), Result, E->getType());
725  }
726
727  return Result;
728}
729
730//===--------------------------------------------------------------------===//
731//                             Expression Emission
732//===--------------------------------------------------------------------===//
733
734
735RValue CodeGenFunction::EmitCallExpr(const CallExpr *E) {
736  if (const ImplicitCastExpr *IcExpr =
737      dyn_cast<const ImplicitCastExpr>(E->getCallee()))
738    if (const DeclRefExpr *DRExpr =
739        dyn_cast<const DeclRefExpr>(IcExpr->getSubExpr()))
740      if (const FunctionDecl *FDecl =
741          dyn_cast<const FunctionDecl>(DRExpr->getDecl()))
742        if (unsigned builtinID = FDecl->getIdentifier()->getBuiltinID())
743          return EmitBuiltinExpr(builtinID, E);
744
745  llvm::Value *Callee = EmitScalarExpr(E->getCallee());
746  return EmitCallExpr(Callee, E->getCallee()->getType(),
747                      E->arg_begin(), E->arg_end());
748}
749
750RValue CodeGenFunction::EmitCallExpr(Expr *FnExpr,
751                                     CallExpr::const_arg_iterator ArgBeg,
752                                     CallExpr::const_arg_iterator ArgEnd) {
753
754  llvm::Value *Callee = EmitScalarExpr(FnExpr);
755  return EmitCallExpr(Callee, FnExpr->getType(), ArgBeg, ArgEnd);
756}
757
758LValue CodeGenFunction::EmitBinaryOperatorLValue(const BinaryOperator *E) {
759  // Can only get l-value for binary operator expressions which are a
760  // simple assignment of aggregate type.
761  if (E->getOpcode() != BinaryOperator::Assign)
762    return EmitUnsupportedLValue(E, "binary l-value expression");
763
764  llvm::Value *Temp = CreateTempAlloca(ConvertType(E->getType()));
765  EmitAggExpr(E, Temp, false);
766  // FIXME: Are these qualifiers correct?
767  return LValue::MakeAddr(Temp, E->getType().getCVRQualifiers());
768}
769
770LValue CodeGenFunction::EmitCallExprLValue(const CallExpr *E) {
771  // Can only get l-value for call expression returning aggregate type
772  RValue RV = EmitCallExpr(E);
773  // FIXME: can this be volatile?
774  return LValue::MakeAddr(RV.getAggregateAddr(),
775                          E->getType().getCVRQualifiers());
776}
777
778LValue CodeGenFunction::EmitObjCMessageExprLValue(const ObjCMessageExpr *E) {
779  // Can only get l-value for message expression returning aggregate type
780  RValue RV = EmitObjCMessageExpr(E);
781  // FIXME: can this be volatile?
782  return LValue::MakeAddr(RV.getAggregateAddr(),
783                          E->getType().getCVRQualifiers());
784}
785
786LValue CodeGenFunction::EmitObjCIvarRefLValue(const ObjCIvarRefExpr *E) {
787  // Objective-C objects are traditionally C structures with their layout
788  // defined at compile-time.  In some implementations, their layout is not
789  // defined until run time in order to allow instance variables to be added to
790  // a class without recompiling all of the subclasses.  If this is the case
791  // then the CGObjCRuntime subclass must return true to LateBoundIvars and
792  // implement the lookup itself.
793  if (CGM.getObjCRuntime().LateBoundIVars()) {
794    return EmitUnsupportedLValue(E, "late-bound instance variables");
795  }
796
797  // FIXME: A lot of the code below could be shared with EmitMemberExpr.
798  llvm::Value *BaseValue = 0;
799  const Expr *BaseExpr = E->getBase();
800  unsigned CVRQualifiers = 0;
801  if (E->isArrow()) {
802    BaseValue = EmitScalarExpr(BaseExpr);
803    const PointerType *PTy =
804      cast<PointerType>(getContext().getCanonicalType(BaseExpr->getType()));
805    CVRQualifiers = PTy->getPointeeType().getCVRQualifiers();
806  } else {
807    LValue BaseLV = EmitLValue(BaseExpr);
808    // FIXME: this isn't right for bitfields.
809    BaseValue = BaseLV.getAddress();
810    CVRQualifiers = BaseExpr->getType().getCVRQualifiers();
811  }
812
813  const ObjCIvarDecl *Field = E->getDecl();
814  if (Field->isBitField())
815    return EmitUnsupportedLValue(E, "ivar bitfields");
816
817  // TODO:  Add a special case for isa (index 0)
818  unsigned Index = CGM.getTypes().getLLVMFieldNo(Field);
819
820  llvm::Value *V = Builder.CreateStructGEP(BaseValue, Index, "tmp");
821  return LValue::MakeAddr(V,
822                          Field->getType().getCVRQualifiers()|CVRQualifiers);
823}
824
825LValue
826CodeGenFunction::EmitObjCPropertyRefLValue(const ObjCPropertyRefExpr *E) {
827  // This is a special l-value that just issues sends when we load or
828  // store through it.
829  return LValue::MakePropertyRef(E, E->getType().getCVRQualifiers());
830}
831
832RValue CodeGenFunction::EmitCallExpr(llvm::Value *Callee, QualType FnType,
833                                     CallExpr::const_arg_iterator ArgBeg,
834                                     CallExpr::const_arg_iterator ArgEnd) {
835
836  // The callee type will always be a pointer to function type, get the function
837  // type.
838  FnType = FnType->getAsPointerType()->getPointeeType();
839  QualType ResultType = FnType->getAsFunctionType()->getResultType();
840
841  CallArgList Args;
842  for (CallExpr::const_arg_iterator I = ArgBeg; I != ArgEnd; ++I)
843    EmitCallArg(*I, Args);
844
845  return EmitCall(Callee, ResultType, Args);
846}
847
848// FIXME: Merge the following two functions.
849void CodeGenFunction::EmitCallArg(RValue RV, QualType Ty,
850                                  CallArgList &Args) {
851  llvm::Value *ArgValue;
852
853  if (RV.isScalar()) {
854    ArgValue = RV.getScalarVal();
855  } else if (RV.isComplex()) {
856    // Make a temporary alloca to pass the argument.
857    ArgValue = CreateTempAlloca(ConvertType(Ty));
858    StoreComplexToAddr(RV.getComplexVal(), ArgValue, false);
859  } else {
860    ArgValue = RV.getAggregateAddr();
861  }
862
863  Args.push_back(std::make_pair(ArgValue, Ty));
864}
865
866void CodeGenFunction::EmitCallArg(const Expr *E, CallArgList &Args) {
867  QualType ArgTy = E->getType();
868  llvm::Value *ArgValue;
869
870  if (!hasAggregateLLVMType(ArgTy)) {
871    // Scalar argument is passed by-value.
872    ArgValue = EmitScalarExpr(E);
873  } else if (ArgTy->isAnyComplexType()) {
874    // Make a temporary alloca to pass the argument.
875    ArgValue = CreateTempAlloca(ConvertType(ArgTy));
876    EmitComplexExprIntoAddr(E, ArgValue, false);
877  } else {
878    ArgValue = CreateTempAlloca(ConvertType(ArgTy));
879    EmitAggExpr(E, ArgValue, false);
880  }
881
882  Args.push_back(std::make_pair(ArgValue, E->getType()));
883}
884
885RValue CodeGenFunction::EmitCall(llvm::Value *Callee,
886                                 QualType ResultType,
887                                 const CallArgList &CallArgs) {
888  // FIXME: Factor out code to load from args into locals into target.
889  llvm::SmallVector<llvm::Value*, 16> Args;
890  llvm::Value *TempArg0 = 0;
891
892  // Handle struct-return functions by passing a pointer to the
893  // location that we would like to return into.
894  if (hasAggregateLLVMType(ResultType)) {
895    // Create a temporary alloca to hold the result of the call. :(
896    TempArg0 = CreateTempAlloca(ConvertType(ResultType));
897    Args.push_back(TempArg0);
898  }
899
900  for (CallArgList::const_iterator I = CallArgs.begin(), E = CallArgs.end();
901       I != E; ++I)
902    Args.push_back(I->first);
903
904  llvm::CallInst *CI = Builder.CreateCall(Callee,&Args[0],&Args[0]+Args.size());
905  CGCallInfo CallInfo(ResultType, CallArgs);
906
907  CodeGen::ParamAttrListType ParamAttrList;
908  CallInfo.constructParamAttrList(ParamAttrList);
909  CI->setParamAttrs(llvm::PAListPtr::get(ParamAttrList.begin(),
910                                         ParamAttrList.size()));
911
912  if (const llvm::Function *F = dyn_cast<llvm::Function>(Callee))
913    CI->setCallingConv(F->getCallingConv());
914  if (CI->getType() != llvm::Type::VoidTy)
915    CI->setName("call");
916  else if (ResultType->isAnyComplexType())
917    return RValue::getComplex(LoadComplexFromAddr(TempArg0, false));
918  else if (hasAggregateLLVMType(ResultType))
919    // Struct return.
920    return RValue::getAggregate(TempArg0);
921  else {
922    // void return.
923    assert(ResultType->isVoidType() && "Should only have a void expr here");
924    CI = 0;
925  }
926
927  return RValue::get(CI);
928}
929