CGExprScalar.cpp revision 55e874299f2ad827646a4ca9ea38c402aaeb38c9 
1//===--- CGExprScalar.cpp - Emit LLVM Code for Scalar Exprs ---------------===//
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 with scalar LLVM types as LLVM code.
11//
12//===----------------------------------------------------------------------===//
13
14#include "CodeGenFunction.h"
15#include "CodeGenModule.h"
16#include "clang/AST/ASTContext.h"
17#include "clang/AST/DeclObjC.h"
18#include "clang/AST/StmtVisitor.h"
19#include "clang/Basic/TargetInfo.h"
20#include "llvm/Constants.h"
21#include "llvm/Function.h"
22#include "llvm/GlobalVariable.h"
23#include "llvm/Intrinsics.h"
24#include "llvm/Support/Compiler.h"
25#include <cstdarg>
26
27using namespace clang;
28using namespace CodeGen;
29using llvm::Value;
30
31//===----------------------------------------------------------------------===//
32//                         Scalar Expression Emitter
33//===----------------------------------------------------------------------===//
34
35struct BinOpInfo {
36  Value *LHS;
37  Value *RHS;
38  QualType Ty;  // Computation Type.
39  const BinaryOperator *E;
40};
41
42namespace {
43class VISIBILITY_HIDDEN ScalarExprEmitter
44  : public StmtVisitor<ScalarExprEmitter, Value*> {
45  CodeGenFunction &CGF;
46  CGBuilderTy &Builder;
47
48public:
49
50  ScalarExprEmitter(CodeGenFunction &cgf) : CGF(cgf),
51    Builder(CGF.Builder) {
52  }
53
54  //===--------------------------------------------------------------------===//
55  //                               Utilities
56  //===--------------------------------------------------------------------===//
57
58  const llvm::Type *ConvertType(QualType T) { return CGF.ConvertType(T); }
59  LValue EmitLValue(const Expr *E) { return CGF.EmitLValue(E); }
60
61  Value *EmitLoadOfLValue(LValue LV, QualType T) {
62    return CGF.EmitLoadOfLValue(LV, T).getScalarVal();
63  }
64
65  /// EmitLoadOfLValue - Given an expression with complex type that represents a
66  /// value l-value, this method emits the address of the l-value, then loads
67  /// and returns the result.
68  Value *EmitLoadOfLValue(const Expr *E) {
69    // FIXME: Volatile
70    return EmitLoadOfLValue(EmitLValue(E), E->getType());
71  }
72
73  /// EmitConversionToBool - Convert the specified expression value to a
74  /// boolean (i1) truth value.  This is equivalent to "Val != 0".
75  Value *EmitConversionToBool(Value *Src, QualType DstTy);
76
77  /// EmitScalarConversion - Emit a conversion from the specified type to the
78  /// specified destination type, both of which are LLVM scalar types.
79  Value *EmitScalarConversion(Value *Src, QualType SrcTy, QualType DstTy);
80
81  /// EmitComplexToScalarConversion - Emit a conversion from the specified
82  /// complex type to the specified destination type, where the destination
83  /// type is an LLVM scalar type.
84  Value *EmitComplexToScalarConversion(CodeGenFunction::ComplexPairTy Src,
85                                       QualType SrcTy, QualType DstTy);
86
87  //===--------------------------------------------------------------------===//
88  //                            Visitor Methods
89  //===--------------------------------------------------------------------===//
90
91  Value *VisitStmt(Stmt *S) {
92    S->dump(CGF.getContext().getSourceManager());
93    assert(0 && "Stmt can't have complex result type!");
94    return 0;
95  }
96  Value *VisitExpr(Expr *S);
97  Value *VisitParenExpr(ParenExpr *PE) { return Visit(PE->getSubExpr()); }
98
99  // Leaves.
100  Value *VisitIntegerLiteral(const IntegerLiteral *E) {
101    return llvm::ConstantInt::get(E->getValue());
102  }
103  Value *VisitFloatingLiteral(const FloatingLiteral *E) {
104    return llvm::ConstantFP::get(E->getValue());
105  }
106  Value *VisitCharacterLiteral(const CharacterLiteral *E) {
107    return llvm::ConstantInt::get(ConvertType(E->getType()), E->getValue());
108  }
109  Value *VisitCXXBoolLiteralExpr(const CXXBoolLiteralExpr *E) {
110    return llvm::ConstantInt::get(ConvertType(E->getType()), E->getValue());
111  }
112  Value *VisitCXXZeroInitValueExpr(const CXXZeroInitValueExpr *E) {
113    return llvm::Constant::getNullValue(ConvertType(E->getType()));
114  }
115  Value *VisitTypesCompatibleExpr(const TypesCompatibleExpr *E) {
116    return llvm::ConstantInt::get(ConvertType(E->getType()),
117                                  CGF.getContext().typesAreCompatible(
118                                    E->getArgType1(), E->getArgType2()));
119  }
120  Value *VisitSizeOfAlignOfTypeExpr(const SizeOfAlignOfTypeExpr *E) {
121    return EmitSizeAlignOf(E->getArgumentType(), E->getType(), E->isSizeOf());
122  }
123  Value *VisitAddrLabelExpr(const AddrLabelExpr *E) {
124    llvm::Value *V =
125      llvm::ConstantInt::get(llvm::Type::Int32Ty,
126                             CGF.GetIDForAddrOfLabel(E->getLabel()));
127
128    return Builder.CreateIntToPtr(V, ConvertType(E->getType()));
129  }
130
131  // l-values.
132  Value *VisitDeclRefExpr(DeclRefExpr *E) {
133    if (const EnumConstantDecl *EC = dyn_cast<EnumConstantDecl>(E->getDecl()))
134      return llvm::ConstantInt::get(EC->getInitVal());
135    return EmitLoadOfLValue(E);
136  }
137  Value *VisitObjCSelectorExpr(ObjCSelectorExpr *E) {
138    return CGF.EmitObjCSelectorExpr(E);
139  }
140  Value *VisitObjCProtocolExpr(ObjCProtocolExpr *E) {
141    return CGF.EmitObjCProtocolExpr(E);
142  }
143  Value *VisitObjCIvarRefExpr(ObjCIvarRefExpr *E) {
144    return EmitLoadOfLValue(E);
145  }
146  Value *VisitObjCPropertyRefExpr(ObjCPropertyRefExpr *E) {
147    return EmitLoadOfLValue(E);
148  }
149  Value *VisitObjCMessageExpr(ObjCMessageExpr *E) {
150    return CGF.EmitObjCMessageExpr(E).getScalarVal();
151  }
152
153  Value *VisitArraySubscriptExpr(ArraySubscriptExpr *E);
154  Value *VisitShuffleVectorExpr(ShuffleVectorExpr *E);
155  Value *VisitMemberExpr(Expr *E)           { return EmitLoadOfLValue(E); }
156  Value *VisitExtVectorElementExpr(Expr *E) { return EmitLoadOfLValue(E); }
157  Value *VisitCompoundLiteralExpr(CompoundLiteralExpr *E) {
158    return EmitLoadOfLValue(E);
159  }
160  Value *VisitStringLiteral(Expr *E)  { return EmitLValue(E).getAddress(); }
161  Value *VisitPredefinedExpr(Expr *E) { return EmitLValue(E).getAddress(); }
162
163  Value *VisitInitListExpr(InitListExpr *E) {
164    unsigned NumInitElements = E->getNumInits();
165
166    const llvm::VectorType *VType =
167      dyn_cast<llvm::VectorType>(ConvertType(E->getType()));
168
169    // We have a scalar in braces. Just use the first element.
170    if (!VType)
171      return Visit(E->getInit(0));
172
173    if (E->hadDesignators()) {
174      CGF.ErrorUnsupported(E, "initializer list with designators");
175      return llvm::UndefValue::get(CGF.ConvertType(E->getType()));
176    }
177
178    unsigned NumVectorElements = VType->getNumElements();
179    const llvm::Type *ElementType = VType->getElementType();
180
181    // Emit individual vector element stores.
182    llvm::Value *V = llvm::UndefValue::get(VType);
183
184    // Emit initializers
185    unsigned i;
186    for (i = 0; i < NumInitElements; ++i) {
187      Value *NewV = Visit(E->getInit(i));
188      Value *Idx = llvm::ConstantInt::get(llvm::Type::Int32Ty, i);
189      V = Builder.CreateInsertElement(V, NewV, Idx);
190    }
191
192    // Emit remaining default initializers
193    for (/* Do not initialize i*/; i < NumVectorElements; ++i) {
194      Value *Idx = llvm::ConstantInt::get(llvm::Type::Int32Ty, i);
195      llvm::Value *NewV = llvm::Constant::getNullValue(ElementType);
196      V = Builder.CreateInsertElement(V, NewV, Idx);
197    }
198
199    return V;
200  }
201
202  Value *VisitImplicitCastExpr(const ImplicitCastExpr *E);
203  Value *VisitCastExpr(const CastExpr *E) {
204    return EmitCastExpr(E->getSubExpr(), E->getType());
205  }
206  Value *EmitCastExpr(const Expr *E, QualType T);
207
208  Value *VisitCallExpr(const CallExpr *E) {
209    return CGF.EmitCallExpr(E).getScalarVal();
210  }
211
212  Value *VisitStmtExpr(const StmtExpr *E);
213
214  // Unary Operators.
215  Value *VisitPrePostIncDec(const UnaryOperator *E, bool isInc, bool isPre);
216  Value *VisitUnaryPostDec(const UnaryOperator *E) {
217    return VisitPrePostIncDec(E, false, false);
218  }
219  Value *VisitUnaryPostInc(const UnaryOperator *E) {
220    return VisitPrePostIncDec(E, true, false);
221  }
222  Value *VisitUnaryPreDec(const UnaryOperator *E) {
223    return VisitPrePostIncDec(E, false, true);
224  }
225  Value *VisitUnaryPreInc(const UnaryOperator *E) {
226    return VisitPrePostIncDec(E, true, true);
227  }
228  Value *VisitUnaryAddrOf(const UnaryOperator *E) {
229    return EmitLValue(E->getSubExpr()).getAddress();
230  }
231  Value *VisitUnaryDeref(const Expr *E) { return EmitLoadOfLValue(E); }
232  Value *VisitUnaryPlus(const UnaryOperator *E) {
233    return Visit(E->getSubExpr());
234  }
235  Value *VisitUnaryMinus    (const UnaryOperator *E);
236  Value *VisitUnaryNot      (const UnaryOperator *E);
237  Value *VisitUnaryLNot     (const UnaryOperator *E);
238  Value *VisitUnarySizeOf   (const UnaryOperator *E) {
239    return EmitSizeAlignOf(E->getSubExpr()->getType(), E->getType(), true);
240  }
241  Value *VisitUnaryAlignOf  (const UnaryOperator *E) {
242    return EmitSizeAlignOf(E->getSubExpr()->getType(), E->getType(), false);
243  }
244  Value *EmitSizeAlignOf(QualType TypeToSize, QualType RetType,
245                         bool isSizeOf);
246  Value *VisitUnaryReal     (const UnaryOperator *E);
247  Value *VisitUnaryImag     (const UnaryOperator *E);
248  Value *VisitUnaryExtension(const UnaryOperator *E) {
249    return Visit(E->getSubExpr());
250  }
251  Value *VisitUnaryOffsetOf(const UnaryOperator *E);
252  Value *VisitCXXDefaultArgExpr(CXXDefaultArgExpr *DAE) {
253    return Visit(DAE->getExpr());
254  }
255
256  // Binary Operators.
257  Value *EmitMul(const BinOpInfo &Ops) {
258    return Builder.CreateMul(Ops.LHS, Ops.RHS, "mul");
259  }
260  Value *EmitDiv(const BinOpInfo &Ops);
261  Value *EmitRem(const BinOpInfo &Ops);
262  Value *EmitAdd(const BinOpInfo &Ops);
263  Value *EmitSub(const BinOpInfo &Ops);
264  Value *EmitShl(const BinOpInfo &Ops);
265  Value *EmitShr(const BinOpInfo &Ops);
266  Value *EmitAnd(const BinOpInfo &Ops) {
267    return Builder.CreateAnd(Ops.LHS, Ops.RHS, "and");
268  }
269  Value *EmitXor(const BinOpInfo &Ops) {
270    return Builder.CreateXor(Ops.LHS, Ops.RHS, "xor");
271  }
272  Value *EmitOr (const BinOpInfo &Ops) {
273    return Builder.CreateOr(Ops.LHS, Ops.RHS, "or");
274  }
275
276  BinOpInfo EmitBinOps(const BinaryOperator *E);
277  Value *EmitCompoundAssign(const CompoundAssignOperator *E,
278                            Value *(ScalarExprEmitter::*F)(const BinOpInfo &));
279
280  // Binary operators and binary compound assignment operators.
281#define HANDLEBINOP(OP) \
282  Value *VisitBin ## OP(const BinaryOperator *E) {                         \
283    return Emit ## OP(EmitBinOps(E));                                      \
284  }                                                                        \
285  Value *VisitBin ## OP ## Assign(const CompoundAssignOperator *E) {       \
286    return EmitCompoundAssign(E, &ScalarExprEmitter::Emit ## OP);          \
287  }
288  HANDLEBINOP(Mul);
289  HANDLEBINOP(Div);
290  HANDLEBINOP(Rem);
291  HANDLEBINOP(Add);
292  HANDLEBINOP(Sub);
293  HANDLEBINOP(Shl);
294  HANDLEBINOP(Shr);
295  HANDLEBINOP(And);
296  HANDLEBINOP(Xor);
297  HANDLEBINOP(Or);
298#undef HANDLEBINOP
299
300  // Comparisons.
301  Value *EmitCompare(const BinaryOperator *E, unsigned UICmpOpc,
302                     unsigned SICmpOpc, unsigned FCmpOpc);
303#define VISITCOMP(CODE, UI, SI, FP) \
304    Value *VisitBin##CODE(const BinaryOperator *E) { \
305      return EmitCompare(E, llvm::ICmpInst::UI, llvm::ICmpInst::SI, \
306                         llvm::FCmpInst::FP); }
307  VISITCOMP(LT, ICMP_ULT, ICMP_SLT, FCMP_OLT);
308  VISITCOMP(GT, ICMP_UGT, ICMP_SGT, FCMP_OGT);
309  VISITCOMP(LE, ICMP_ULE, ICMP_SLE, FCMP_OLE);
310  VISITCOMP(GE, ICMP_UGE, ICMP_SGE, FCMP_OGE);
311  VISITCOMP(EQ, ICMP_EQ , ICMP_EQ , FCMP_OEQ);
312  VISITCOMP(NE, ICMP_NE , ICMP_NE , FCMP_UNE);
313#undef VISITCOMP
314
315  Value *VisitBinAssign     (const BinaryOperator *E);
316
317  Value *VisitBinLAnd       (const BinaryOperator *E);
318  Value *VisitBinLOr        (const BinaryOperator *E);
319  Value *VisitBinComma      (const BinaryOperator *E);
320
321  // Other Operators.
322  Value *VisitConditionalOperator(const ConditionalOperator *CO);
323  Value *VisitChooseExpr(ChooseExpr *CE);
324  Value *VisitOverloadExpr(OverloadExpr *OE);
325  Value *VisitVAArgExpr(VAArgExpr *VE);
326  Value *VisitObjCStringLiteral(const ObjCStringLiteral *E) {
327    return CGF.EmitObjCStringLiteral(E);
328  }
329  Value *VisitObjCEncodeExpr(const ObjCEncodeExpr *E);
330};
331}  // end anonymous namespace.
332
333//===----------------------------------------------------------------------===//
334//                                Utilities
335//===----------------------------------------------------------------------===//
336
337/// EmitConversionToBool - Convert the specified expression value to a
338/// boolean (i1) truth value.  This is equivalent to "Val != 0".
339Value *ScalarExprEmitter::EmitConversionToBool(Value *Src, QualType SrcType) {
340  assert(SrcType->isCanonical() && "EmitScalarConversion strips typedefs");
341
342  if (SrcType->isRealFloatingType()) {
343    // Compare against 0.0 for fp scalars.
344    llvm::Value *Zero = llvm::Constant::getNullValue(Src->getType());
345    return Builder.CreateFCmpUNE(Src, Zero, "tobool");
346  }
347
348  assert((SrcType->isIntegerType() || isa<llvm::PointerType>(Src->getType())) &&
349         "Unknown scalar type to convert");
350
351  // Because of the type rules of C, we often end up computing a logical value,
352  // then zero extending it to int, then wanting it as a logical value again.
353  // Optimize this common case.
354  if (llvm::ZExtInst *ZI = dyn_cast<llvm::ZExtInst>(Src)) {
355    if (ZI->getOperand(0)->getType() == llvm::Type::Int1Ty) {
356      Value *Result = ZI->getOperand(0);
357      // If there aren't any more uses, zap the instruction to save space.
358      // Note that there can be more uses, for example if this
359      // is the result of an assignment.
360      if (ZI->use_empty())
361        ZI->eraseFromParent();
362      return Result;
363    }
364  }
365
366  // Compare against an integer or pointer null.
367  llvm::Value *Zero = llvm::Constant::getNullValue(Src->getType());
368  return Builder.CreateICmpNE(Src, Zero, "tobool");
369}
370
371/// EmitScalarConversion - Emit a conversion from the specified type to the
372/// specified destination type, both of which are LLVM scalar types.
373Value *ScalarExprEmitter::EmitScalarConversion(Value *Src, QualType SrcType,
374                                               QualType DstType) {
375  SrcType = CGF.getContext().getCanonicalType(SrcType);
376  DstType = CGF.getContext().getCanonicalType(DstType);
377  if (SrcType == DstType) return Src;
378
379  if (DstType->isVoidType()) return 0;
380
381  // Handle conversions to bool first, they are special: comparisons against 0.
382  if (DstType->isBooleanType())
383    return EmitConversionToBool(Src, SrcType);
384
385  const llvm::Type *DstTy = ConvertType(DstType);
386
387  // Ignore conversions like int -> uint.
388  if (Src->getType() == DstTy)
389    return Src;
390
391  // Handle pointer conversions next: pointers can only be converted
392  // to/from other pointers and integers. Check for pointer types in
393  // terms of LLVM, as some native types (like Obj-C id) may map to a
394  // pointer type.
395  if (isa<llvm::PointerType>(DstTy)) {
396    // The source value may be an integer, or a pointer.
397    if (isa<llvm::PointerType>(Src->getType()))
398      return Builder.CreateBitCast(Src, DstTy, "conv");
399    assert(SrcType->isIntegerType() && "Not ptr->ptr or int->ptr conversion?");
400    return Builder.CreateIntToPtr(Src, DstTy, "conv");
401  }
402
403  if (isa<llvm::PointerType>(Src->getType())) {
404    // Must be an ptr to int cast.
405    assert(isa<llvm::IntegerType>(DstTy) && "not ptr->int?");
406    return Builder.CreatePtrToInt(Src, DstTy, "conv");
407  }
408
409  // A scalar can be splatted to an extended vector of the same element type
410  if (DstType->isExtVectorType() && !isa<VectorType>(SrcType) &&
411      cast<llvm::VectorType>(DstTy)->getElementType() == Src->getType())
412    return CGF.EmitVector(&Src, DstType->getAsVectorType()->getNumElements(),
413                          true);
414
415  // Allow bitcast from vector to integer/fp of the same size.
416  if (isa<llvm::VectorType>(Src->getType()) ||
417      isa<llvm::VectorType>(DstTy))
418    return Builder.CreateBitCast(Src, DstTy, "conv");
419
420  // Finally, we have the arithmetic types: real int/float.
421  if (isa<llvm::IntegerType>(Src->getType())) {
422    bool InputSigned = SrcType->isSignedIntegerType();
423    if (isa<llvm::IntegerType>(DstTy))
424      return Builder.CreateIntCast(Src, DstTy, InputSigned, "conv");
425    else if (InputSigned)
426      return Builder.CreateSIToFP(Src, DstTy, "conv");
427    else
428      return Builder.CreateUIToFP(Src, DstTy, "conv");
429  }
430
431  assert(Src->getType()->isFloatingPoint() && "Unknown real conversion");
432  if (isa<llvm::IntegerType>(DstTy)) {
433    if (DstType->isSignedIntegerType())
434      return Builder.CreateFPToSI(Src, DstTy, "conv");
435    else
436      return Builder.CreateFPToUI(Src, DstTy, "conv");
437  }
438
439  assert(DstTy->isFloatingPoint() && "Unknown real conversion");
440  if (DstTy->getTypeID() < Src->getType()->getTypeID())
441    return Builder.CreateFPTrunc(Src, DstTy, "conv");
442  else
443    return Builder.CreateFPExt(Src, DstTy, "conv");
444}
445
446/// EmitComplexToScalarConversion - Emit a conversion from the specified
447/// complex type to the specified destination type, where the destination
448/// type is an LLVM scalar type.
449Value *ScalarExprEmitter::
450EmitComplexToScalarConversion(CodeGenFunction::ComplexPairTy Src,
451                              QualType SrcTy, QualType DstTy) {
452  // Get the source element type.
453  SrcTy = SrcTy->getAsComplexType()->getElementType();
454
455  // Handle conversions to bool first, they are special: comparisons against 0.
456  if (DstTy->isBooleanType()) {
457    //  Complex != 0  -> (Real != 0) | (Imag != 0)
458    Src.first  = EmitScalarConversion(Src.first, SrcTy, DstTy);
459    Src.second = EmitScalarConversion(Src.second, SrcTy, DstTy);
460    return Builder.CreateOr(Src.first, Src.second, "tobool");
461  }
462
463  // C99 6.3.1.7p2: "When a value of complex type is converted to a real type,
464  // the imaginary part of the complex value is discarded and the value of the
465  // real part is converted according to the conversion rules for the
466  // corresponding real type.
467  return EmitScalarConversion(Src.first, SrcTy, DstTy);
468}
469
470
471//===----------------------------------------------------------------------===//
472//                            Visitor Methods
473//===----------------------------------------------------------------------===//
474
475Value *ScalarExprEmitter::VisitExpr(Expr *E) {
476  CGF.ErrorUnsupported(E, "scalar expression");
477  if (E->getType()->isVoidType())
478    return 0;
479  return llvm::UndefValue::get(CGF.ConvertType(E->getType()));
480}
481
482Value *ScalarExprEmitter::VisitShuffleVectorExpr(ShuffleVectorExpr *E) {
483  llvm::SmallVector<llvm::Constant*, 32> indices;
484  for (unsigned i = 2; i < E->getNumSubExprs(); i++) {
485    indices.push_back(cast<llvm::Constant>(CGF.EmitScalarExpr(E->getExpr(i))));
486  }
487  Value* V1 = CGF.EmitScalarExpr(E->getExpr(0));
488  Value* V2 = CGF.EmitScalarExpr(E->getExpr(1));
489  Value* SV = llvm::ConstantVector::get(indices.begin(), indices.size());
490  return Builder.CreateShuffleVector(V1, V2, SV, "shuffle");
491}
492
493Value *ScalarExprEmitter::VisitArraySubscriptExpr(ArraySubscriptExpr *E) {
494  // Emit subscript expressions in rvalue context's.  For most cases, this just
495  // loads the lvalue formed by the subscript expr.  However, we have to be
496  // careful, because the base of a vector subscript is occasionally an rvalue,
497  // so we can't get it as an lvalue.
498  if (!E->getBase()->getType()->isVectorType())
499    return EmitLoadOfLValue(E);
500
501  // Handle the vector case.  The base must be a vector, the index must be an
502  // integer value.
503  Value *Base = Visit(E->getBase());
504  Value *Idx  = Visit(E->getIdx());
505
506  // FIXME: Convert Idx to i32 type.
507  return Builder.CreateExtractElement(Base, Idx, "vecext");
508}
509
510/// VisitImplicitCastExpr - Implicit casts are the same as normal casts, but
511/// also handle things like function to pointer-to-function decay, and array to
512/// pointer decay.
513Value *ScalarExprEmitter::VisitImplicitCastExpr(const ImplicitCastExpr *E) {
514  const Expr *Op = E->getSubExpr();
515
516  // If this is due to array->pointer conversion, emit the array expression as
517  // an l-value.
518  if (Op->getType()->isArrayType()) {
519    // FIXME: For now we assume that all source arrays map to LLVM arrays.  This
520    // will not true when we add support for VLAs.
521    Value *V = EmitLValue(Op).getAddress();  // Bitfields can't be arrays.
522
523    if (!(isa<llvm::PointerType>(V->getType()) &&
524          isa<llvm::ArrayType>(cast<llvm::PointerType>(V->getType())
525                               ->getElementType()))) {
526      CGF.ErrorUnsupported(E, "variable-length array cast", true);
527      if (E->getType()->isVoidType())
528        return 0;
529      return llvm::UndefValue::get(CGF.ConvertType(E->getType()));
530    }
531    V = Builder.CreateStructGEP(V, 0, "arraydecay");
532
533    // The resultant pointer type can be implicitly casted to other pointer
534    // types as well (e.g. void*) and can be implicitly converted to integer.
535    const llvm::Type *DestTy = ConvertType(E->getType());
536    if (V->getType() != DestTy) {
537      if (isa<llvm::PointerType>(DestTy))
538        V = Builder.CreateBitCast(V, DestTy, "ptrconv");
539      else {
540        assert(isa<llvm::IntegerType>(DestTy) && "Unknown array decay");
541        V = Builder.CreatePtrToInt(V, DestTy, "ptrconv");
542      }
543    }
544    return V;
545
546  } else if (E->getType()->isReferenceType()) {
547    return EmitLValue(Op).getAddress();
548  }
549
550  return EmitCastExpr(Op, E->getType());
551}
552
553
554// VisitCastExpr - Emit code for an explicit or implicit cast.  Implicit casts
555// have to handle a more broad range of conversions than explicit casts, as they
556// handle things like function to ptr-to-function decay etc.
557Value *ScalarExprEmitter::EmitCastExpr(const Expr *E, QualType DestTy) {
558  // Handle cases where the source is an non-complex type.
559
560  if (!CGF.hasAggregateLLVMType(E->getType())) {
561    Value *Src = Visit(const_cast<Expr*>(E));
562
563    // Use EmitScalarConversion to perform the conversion.
564    return EmitScalarConversion(Src, E->getType(), DestTy);
565  }
566
567  if (E->getType()->isAnyComplexType()) {
568    // Handle cases where the source is a complex type.
569    return EmitComplexToScalarConversion(CGF.EmitComplexExpr(E), E->getType(),
570                                         DestTy);
571  }
572
573  // Okay, this is a cast from an aggregate.  It must be a cast to void.  Just
574  // evaluate the result and return.
575  CGF.EmitAggExpr(E, 0, false);
576  return 0;
577}
578
579Value *ScalarExprEmitter::VisitStmtExpr(const StmtExpr *E) {
580  return CGF.EmitCompoundStmt(*E->getSubStmt(),
581                              !E->getType()->isVoidType()).getScalarVal();
582}
583
584
585//===----------------------------------------------------------------------===//
586//                             Unary Operators
587//===----------------------------------------------------------------------===//
588
589Value *ScalarExprEmitter::VisitPrePostIncDec(const UnaryOperator *E,
590                                             bool isInc, bool isPre) {
591  LValue LV = EmitLValue(E->getSubExpr());
592  // FIXME: Handle volatile!
593  Value *InVal = CGF.EmitLoadOfLValue(LV, // false
594                                     E->getSubExpr()->getType()).getScalarVal();
595
596  int AmountVal = isInc ? 1 : -1;
597
598  Value *NextVal;
599  if (isa<llvm::PointerType>(InVal->getType())) {
600    // FIXME: This isn't right for VLAs.
601    NextVal = llvm::ConstantInt::get(llvm::Type::Int32Ty, AmountVal);
602    NextVal = Builder.CreateGEP(InVal, NextVal, "ptrincdec");
603  } else {
604    // Add the inc/dec to the real part.
605    if (isa<llvm::IntegerType>(InVal->getType()))
606      NextVal = llvm::ConstantInt::get(InVal->getType(), AmountVal);
607    else if (InVal->getType() == llvm::Type::FloatTy)
608      NextVal =
609        llvm::ConstantFP::get(llvm::APFloat(static_cast<float>(AmountVal)));
610    else if (InVal->getType() == llvm::Type::DoubleTy)
611      NextVal =
612        llvm::ConstantFP::get(llvm::APFloat(static_cast<double>(AmountVal)));
613    else {
614      llvm::APFloat F(static_cast<float>(AmountVal));
615      bool ignored;
616      F.convert(CGF.Target.getLongDoubleFormat(), llvm::APFloat::rmTowardZero,
617                &ignored);
618      NextVal = llvm::ConstantFP::get(F);
619    }
620    NextVal = Builder.CreateAdd(InVal, NextVal, isInc ? "inc" : "dec");
621  }
622
623  // Store the updated result through the lvalue.
624  CGF.EmitStoreThroughLValue(RValue::get(NextVal), LV,
625                             E->getSubExpr()->getType());
626
627  // If this is a postinc, return the value read from memory, otherwise use the
628  // updated value.
629  return isPre ? NextVal : InVal;
630}
631
632
633Value *ScalarExprEmitter::VisitUnaryMinus(const UnaryOperator *E) {
634  Value *Op = Visit(E->getSubExpr());
635  return Builder.CreateNeg(Op, "neg");
636}
637
638Value *ScalarExprEmitter::VisitUnaryNot(const UnaryOperator *E) {
639  Value *Op = Visit(E->getSubExpr());
640  return Builder.CreateNot(Op, "neg");
641}
642
643Value *ScalarExprEmitter::VisitUnaryLNot(const UnaryOperator *E) {
644  // Compare operand to zero.
645  Value *BoolVal = CGF.EvaluateExprAsBool(E->getSubExpr());
646
647  // Invert value.
648  // TODO: Could dynamically modify easy computations here.  For example, if
649  // the operand is an icmp ne, turn into icmp eq.
650  BoolVal = Builder.CreateNot(BoolVal, "lnot");
651
652  // ZExt result to int.
653  return Builder.CreateZExt(BoolVal, CGF.LLVMIntTy, "lnot.ext");
654}
655
656/// EmitSizeAlignOf - Return the size or alignment of the 'TypeToSize' type as
657/// an integer (RetType).
658Value *ScalarExprEmitter::EmitSizeAlignOf(QualType TypeToSize,
659                                          QualType RetType,bool isSizeOf){
660  assert(RetType->isIntegerType() && "Result type must be an integer!");
661  uint32_t ResultWidth =
662    static_cast<uint32_t>(CGF.getContext().getTypeSize(RetType));
663
664  // sizeof(void) and __alignof__(void) = 1 as a gcc extension. Also
665  // for function types.
666  // FIXME: what is alignof a function type in gcc?
667  if (TypeToSize->isVoidType() || TypeToSize->isFunctionType())
668    return llvm::ConstantInt::get(llvm::APInt(ResultWidth, 1));
669
670  /// FIXME: This doesn't handle VLAs yet!
671  std::pair<uint64_t, unsigned> Info = CGF.getContext().getTypeInfo(TypeToSize);
672
673  uint64_t Val = isSizeOf ? Info.first : Info.second;
674  Val /= 8;  // Return size in bytes, not bits.
675
676  return llvm::ConstantInt::get(llvm::APInt(ResultWidth, Val));
677}
678
679Value *ScalarExprEmitter::VisitUnaryReal(const UnaryOperator *E) {
680  Expr *Op = E->getSubExpr();
681  if (Op->getType()->isAnyComplexType())
682    return CGF.EmitComplexExpr(Op).first;
683  return Visit(Op);
684}
685Value *ScalarExprEmitter::VisitUnaryImag(const UnaryOperator *E) {
686  Expr *Op = E->getSubExpr();
687  if (Op->getType()->isAnyComplexType())
688    return CGF.EmitComplexExpr(Op).second;
689
690  // __imag on a scalar returns zero.  Emit it the subexpr to ensure side
691  // effects are evaluated.
692  CGF.EmitScalarExpr(Op);
693  return llvm::Constant::getNullValue(ConvertType(E->getType()));
694}
695
696Value *ScalarExprEmitter::VisitUnaryOffsetOf(const UnaryOperator *E)
697{
698  int64_t Val = E->evaluateOffsetOf(CGF.getContext());
699
700  assert(E->getType()->isIntegerType() && "Result type must be an integer!");
701
702  uint32_t ResultWidth =
703    static_cast<uint32_t>(CGF.getContext().getTypeSize(E->getType()));
704  return llvm::ConstantInt::get(llvm::APInt(ResultWidth, Val));
705}
706
707//===----------------------------------------------------------------------===//
708//                           Binary Operators
709//===----------------------------------------------------------------------===//
710
711BinOpInfo ScalarExprEmitter::EmitBinOps(const BinaryOperator *E) {
712  BinOpInfo Result;
713  Result.LHS = Visit(E->getLHS());
714  Result.RHS = Visit(E->getRHS());
715  Result.Ty  = E->getType();
716  Result.E = E;
717  return Result;
718}
719
720Value *ScalarExprEmitter::EmitCompoundAssign(const CompoundAssignOperator *E,
721                      Value *(ScalarExprEmitter::*Func)(const BinOpInfo &)) {
722  QualType LHSTy = E->getLHS()->getType(), RHSTy = E->getRHS()->getType();
723
724  BinOpInfo OpInfo;
725
726  // Load the LHS and RHS operands.
727  LValue LHSLV = EmitLValue(E->getLHS());
728  OpInfo.LHS = EmitLoadOfLValue(LHSLV, LHSTy);
729
730  // Determine the computation type.  If the RHS is complex, then this is one of
731  // the add/sub/mul/div operators.  All of these operators can be computed in
732  // with just their real component even though the computation domain really is
733  // complex.
734  QualType ComputeType = E->getComputationType();
735
736  // If the computation type is complex, then the RHS is complex.  Emit the RHS.
737  if (const ComplexType *CT = ComputeType->getAsComplexType()) {
738    ComputeType = CT->getElementType();
739
740    // Emit the RHS, only keeping the real component.
741    OpInfo.RHS = CGF.EmitComplexExpr(E->getRHS()).first;
742    RHSTy = RHSTy->getAsComplexType()->getElementType();
743  } else {
744    // Otherwise the RHS is a simple scalar value.
745    OpInfo.RHS = Visit(E->getRHS());
746  }
747
748  QualType LComputeTy, RComputeTy, ResultTy;
749
750  // Compound assignment does not contain enough information about all
751  // the types involved for pointer arithmetic cases. Figure it out
752  // here for now.
753  if (E->getLHS()->getType()->isPointerType()) {
754    // Pointer arithmetic cases: ptr +=,-= int and ptr -= ptr,
755    assert((E->getOpcode() == BinaryOperator::AddAssign ||
756            E->getOpcode() == BinaryOperator::SubAssign) &&
757           "Invalid compound assignment operator on pointer type.");
758    LComputeTy = E->getLHS()->getType();
759
760    if (E->getRHS()->getType()->isPointerType()) {
761      // Degenerate case of (ptr -= ptr) allowed by GCC implicit cast
762      // extension, the conversion from the pointer difference back to
763      // the LHS type is handled at the end.
764      assert(E->getOpcode() == BinaryOperator::SubAssign &&
765             "Invalid compound assignment operator on pointer type.");
766      RComputeTy = E->getLHS()->getType();
767      ResultTy = CGF.getContext().getPointerDiffType();
768    } else {
769      RComputeTy = E->getRHS()->getType();
770      ResultTy = LComputeTy;
771    }
772  } else if (E->getRHS()->getType()->isPointerType()) {
773    // Degenerate case of (int += ptr) allowed by GCC implicit cast
774    // extension.
775    assert(E->getOpcode() == BinaryOperator::AddAssign &&
776           "Invalid compound assignment operator on pointer type.");
777    LComputeTy = E->getLHS()->getType();
778    RComputeTy = E->getRHS()->getType();
779    ResultTy = RComputeTy;
780  } else {
781    LComputeTy = RComputeTy = ResultTy = ComputeType;
782  }
783
784  // Convert the LHS/RHS values to the computation type.
785  OpInfo.LHS = EmitScalarConversion(OpInfo.LHS, LHSTy, LComputeTy);
786  OpInfo.RHS = EmitScalarConversion(OpInfo.RHS, RHSTy, RComputeTy);
787  OpInfo.Ty = ResultTy;
788  OpInfo.E = E;
789
790  // Expand the binary operator.
791  Value *Result = (this->*Func)(OpInfo);
792
793  // Convert the result back to the LHS type.
794  Result = EmitScalarConversion(Result, ResultTy, LHSTy);
795
796  // Store the result value into the LHS lvalue.
797  CGF.EmitStoreThroughLValue(RValue::get(Result), LHSLV, LHSTy);
798
799  // For bitfields, we need the value in the bitfield. Note that
800  // property references do not reload their value (even though the
801  // setter may have changed it).
802  // FIXME: This adds an extra bitfield load
803  if (LHSLV.isBitfield())
804    Result = EmitLoadOfLValue(LHSLV, LHSTy);
805  return Result;
806}
807
808
809Value *ScalarExprEmitter::EmitDiv(const BinOpInfo &Ops) {
810  if (Ops.LHS->getType()->isFPOrFPVector())
811    return Builder.CreateFDiv(Ops.LHS, Ops.RHS, "div");
812  else if (Ops.Ty->isUnsignedIntegerType())
813    return Builder.CreateUDiv(Ops.LHS, Ops.RHS, "div");
814  else
815    return Builder.CreateSDiv(Ops.LHS, Ops.RHS, "div");
816}
817
818Value *ScalarExprEmitter::EmitRem(const BinOpInfo &Ops) {
819  // Rem in C can't be a floating point type: C99 6.5.5p2.
820  if (Ops.Ty->isUnsignedIntegerType())
821    return Builder.CreateURem(Ops.LHS, Ops.RHS, "rem");
822  else
823    return Builder.CreateSRem(Ops.LHS, Ops.RHS, "rem");
824}
825
826
827Value *ScalarExprEmitter::EmitAdd(const BinOpInfo &Ops) {
828  if (!Ops.Ty->isPointerType())
829    return Builder.CreateAdd(Ops.LHS, Ops.RHS, "add");
830
831  // FIXME: What about a pointer to a VLA?
832  Value *Ptr, *Idx;
833  Expr *IdxExp;
834  if (isa<llvm::PointerType>(Ops.LHS->getType())) {  // pointer + int
835    Ptr = Ops.LHS;
836    Idx = Ops.RHS;
837    IdxExp = Ops.E->getRHS();
838  } else {                                           // int + pointer
839    Ptr = Ops.RHS;
840    Idx = Ops.LHS;
841    IdxExp = Ops.E->getLHS();
842  }
843
844  unsigned Width = cast<llvm::IntegerType>(Idx->getType())->getBitWidth();
845  if (Width < CGF.LLVMPointerWidth) {
846    // Zero or sign extend the pointer value based on whether the index is
847    // signed or not.
848    const llvm::Type *IdxType = llvm::IntegerType::get(CGF.LLVMPointerWidth);
849    if (IdxExp->getType()->isSignedIntegerType())
850      Idx = Builder.CreateSExt(Idx, IdxType, "idx.ext");
851    else
852      Idx = Builder.CreateZExt(Idx, IdxType, "idx.ext");
853  }
854
855  return Builder.CreateGEP(Ptr, Idx, "add.ptr");
856}
857
858Value *ScalarExprEmitter::EmitSub(const BinOpInfo &Ops) {
859  if (!isa<llvm::PointerType>(Ops.LHS->getType()))
860    return Builder.CreateSub(Ops.LHS, Ops.RHS, "sub");
861
862  if (!isa<llvm::PointerType>(Ops.RHS->getType())) {
863    // pointer - int
864    Value *Idx = Ops.RHS;
865    unsigned Width = cast<llvm::IntegerType>(Idx->getType())->getBitWidth();
866    if (Width < CGF.LLVMPointerWidth) {
867      // Zero or sign extend the pointer value based on whether the index is
868      // signed or not.
869      const llvm::Type *IdxType = llvm::IntegerType::get(CGF.LLVMPointerWidth);
870      if (Ops.E->getRHS()->getType()->isSignedIntegerType())
871        Idx = Builder.CreateSExt(Idx, IdxType, "idx.ext");
872      else
873        Idx = Builder.CreateZExt(Idx, IdxType, "idx.ext");
874    }
875    Idx = Builder.CreateNeg(Idx, "sub.ptr.neg");
876
877    // FIXME: The pointer could point to a VLA.
878    // The GNU void* - int case is automatically handled here because
879    // our LLVM type for void* is i8*.
880    return Builder.CreateGEP(Ops.LHS, Idx, "sub.ptr");
881  } else {
882    // pointer - pointer
883    Value *LHS = Ops.LHS;
884    Value *RHS = Ops.RHS;
885
886    const QualType LHSType = Ops.E->getLHS()->getType();
887    const QualType LHSElementType = LHSType->getAsPointerType()->getPointeeType();
888    uint64_t ElementSize;
889
890    // Handle GCC extension for pointer arithmetic on void* types.
891    if (LHSElementType->isVoidType()) {
892      ElementSize = 1;
893    } else {
894      ElementSize = CGF.getContext().getTypeSize(LHSElementType) / 8;
895    }
896
897    const llvm::Type *ResultType = ConvertType(Ops.Ty);
898    LHS = Builder.CreatePtrToInt(LHS, ResultType, "sub.ptr.lhs.cast");
899    RHS = Builder.CreatePtrToInt(RHS, ResultType, "sub.ptr.rhs.cast");
900    Value *BytesBetween = Builder.CreateSub(LHS, RHS, "sub.ptr.sub");
901
902    // HACK: LLVM doesn't have an divide instruction that 'knows' there is no
903    // remainder.  As such, we handle common power-of-two cases here to generate
904    // better code. See PR2247.
905    if (llvm::isPowerOf2_64(ElementSize)) {
906      Value *ShAmt =
907        llvm::ConstantInt::get(ResultType, llvm::Log2_64(ElementSize));
908      return Builder.CreateAShr(BytesBetween, ShAmt, "sub.ptr.shr");
909    }
910
911    // Otherwise, do a full sdiv.
912    Value *BytesPerElt = llvm::ConstantInt::get(ResultType, ElementSize);
913    return Builder.CreateSDiv(BytesBetween, BytesPerElt, "sub.ptr.div");
914  }
915}
916
917Value *ScalarExprEmitter::EmitShl(const BinOpInfo &Ops) {
918  // LLVM requires the LHS and RHS to be the same type: promote or truncate the
919  // RHS to the same size as the LHS.
920  Value *RHS = Ops.RHS;
921  if (Ops.LHS->getType() != RHS->getType())
922    RHS = Builder.CreateIntCast(RHS, Ops.LHS->getType(), false, "sh_prom");
923
924  return Builder.CreateShl(Ops.LHS, RHS, "shl");
925}
926
927Value *ScalarExprEmitter::EmitShr(const BinOpInfo &Ops) {
928  // LLVM requires the LHS and RHS to be the same type: promote or truncate the
929  // RHS to the same size as the LHS.
930  Value *RHS = Ops.RHS;
931  if (Ops.LHS->getType() != RHS->getType())
932    RHS = Builder.CreateIntCast(RHS, Ops.LHS->getType(), false, "sh_prom");
933
934  if (Ops.Ty->isUnsignedIntegerType())
935    return Builder.CreateLShr(Ops.LHS, RHS, "shr");
936  return Builder.CreateAShr(Ops.LHS, RHS, "shr");
937}
938
939Value *ScalarExprEmitter::EmitCompare(const BinaryOperator *E,unsigned UICmpOpc,
940                                      unsigned SICmpOpc, unsigned FCmpOpc) {
941  Value *Result;
942  QualType LHSTy = E->getLHS()->getType();
943  if (!LHSTy->isAnyComplexType() && !LHSTy->isVectorType()) {
944    Value *LHS = Visit(E->getLHS());
945    Value *RHS = Visit(E->getRHS());
946
947    if (LHS->getType()->isFloatingPoint()) {
948      Result = Builder.CreateFCmp((llvm::CmpInst::Predicate)FCmpOpc,
949                                  LHS, RHS, "cmp");
950    } else if (LHSTy->isSignedIntegerType()) {
951      Result = Builder.CreateICmp((llvm::ICmpInst::Predicate)SICmpOpc,
952                                  LHS, RHS, "cmp");
953    } else {
954      // Unsigned integers and pointers.
955      Result = Builder.CreateICmp((llvm::ICmpInst::Predicate)UICmpOpc,
956                                  LHS, RHS, "cmp");
957    }
958  } else if (LHSTy->isVectorType()) {
959    Value *LHS = Visit(E->getLHS());
960    Value *RHS = Visit(E->getRHS());
961
962    if (LHS->getType()->isFPOrFPVector()) {
963      Result = Builder.CreateVFCmp((llvm::CmpInst::Predicate)FCmpOpc,
964                                  LHS, RHS, "cmp");
965    } else if (LHSTy->isUnsignedIntegerType()) {
966      Result = Builder.CreateVICmp((llvm::CmpInst::Predicate)UICmpOpc,
967                                  LHS, RHS, "cmp");
968    } else {
969      // Signed integers and pointers.
970      Result = Builder.CreateVICmp((llvm::CmpInst::Predicate)SICmpOpc,
971                                  LHS, RHS, "cmp");
972    }
973    return Result;
974  } else {
975    // Complex Comparison: can only be an equality comparison.
976    CodeGenFunction::ComplexPairTy LHS = CGF.EmitComplexExpr(E->getLHS());
977    CodeGenFunction::ComplexPairTy RHS = CGF.EmitComplexExpr(E->getRHS());
978
979    QualType CETy = LHSTy->getAsComplexType()->getElementType();
980
981    Value *ResultR, *ResultI;
982    if (CETy->isRealFloatingType()) {
983      ResultR = Builder.CreateFCmp((llvm::FCmpInst::Predicate)FCmpOpc,
984                                   LHS.first, RHS.first, "cmp.r");
985      ResultI = Builder.CreateFCmp((llvm::FCmpInst::Predicate)FCmpOpc,
986                                   LHS.second, RHS.second, "cmp.i");
987    } else {
988      // Complex comparisons can only be equality comparisons.  As such, signed
989      // and unsigned opcodes are the same.
990      ResultR = Builder.CreateICmp((llvm::ICmpInst::Predicate)UICmpOpc,
991                                   LHS.first, RHS.first, "cmp.r");
992      ResultI = Builder.CreateICmp((llvm::ICmpInst::Predicate)UICmpOpc,
993                                   LHS.second, RHS.second, "cmp.i");
994    }
995
996    if (E->getOpcode() == BinaryOperator::EQ) {
997      Result = Builder.CreateAnd(ResultR, ResultI, "and.ri");
998    } else {
999      assert(E->getOpcode() == BinaryOperator::NE &&
1000             "Complex comparison other than == or != ?");
1001      Result = Builder.CreateOr(ResultR, ResultI, "or.ri");
1002    }
1003  }
1004
1005  // ZExt result to int.
1006  return Builder.CreateZExt(Result, CGF.LLVMIntTy, "cmp.ext");
1007}
1008
1009Value *ScalarExprEmitter::VisitBinAssign(const BinaryOperator *E) {
1010  LValue LHS = EmitLValue(E->getLHS());
1011  Value *RHS = Visit(E->getRHS());
1012
1013  // Store the value into the LHS.
1014  // FIXME: Volatility!
1015  CGF.EmitStoreThroughLValue(RValue::get(RHS), LHS, E->getType());
1016
1017  // For bitfields, we need the value in the bitfield. Note that
1018  // property references do not reload their value (even though the
1019  // setter may have changed it).
1020  // FIXME: This adds an extra bitfield load
1021  if (LHS.isBitfield())
1022    return EmitLoadOfLValue(LHS, E->getLHS()->getType());
1023
1024  // Return the RHS.
1025  return RHS;
1026}
1027
1028Value *ScalarExprEmitter::VisitBinLAnd(const BinaryOperator *E) {
1029  Value *LHSCond = CGF.EvaluateExprAsBool(E->getLHS());
1030
1031  llvm::BasicBlock *ContBlock = llvm::BasicBlock::Create("land_cont");
1032  llvm::BasicBlock *RHSBlock = llvm::BasicBlock::Create("land_rhs");
1033
1034  llvm::BasicBlock *OrigBlock = Builder.GetInsertBlock();
1035  Builder.CreateCondBr(LHSCond, RHSBlock, ContBlock);
1036
1037  CGF.EmitBlock(RHSBlock);
1038  Value *RHSCond = CGF.EvaluateExprAsBool(E->getRHS());
1039
1040  // Reaquire the RHS block, as there may be subblocks inserted.
1041  RHSBlock = Builder.GetInsertBlock();
1042  CGF.EmitBlock(ContBlock);
1043
1044  // Create a PHI node.  If we just evaluted the LHS condition, the result is
1045  // false.  If we evaluated both, the result is the RHS condition.
1046  llvm::PHINode *PN = Builder.CreatePHI(llvm::Type::Int1Ty, "land");
1047  PN->reserveOperandSpace(2);
1048  PN->addIncoming(llvm::ConstantInt::getFalse(), OrigBlock);
1049  PN->addIncoming(RHSCond, RHSBlock);
1050
1051  // ZExt result to int.
1052  return Builder.CreateZExt(PN, CGF.LLVMIntTy, "land.ext");
1053}
1054
1055Value *ScalarExprEmitter::VisitBinLOr(const BinaryOperator *E) {
1056  Value *LHSCond = CGF.EvaluateExprAsBool(E->getLHS());
1057
1058  llvm::BasicBlock *ContBlock = CGF.createBasicBlock("lor_cont");
1059  llvm::BasicBlock *RHSBlock = CGF.createBasicBlock("lor_rhs");
1060
1061  llvm::BasicBlock *OrigBlock = Builder.GetInsertBlock();
1062  Builder.CreateCondBr(LHSCond, ContBlock, RHSBlock);
1063
1064  CGF.EmitBlock(RHSBlock);
1065  Value *RHSCond = CGF.EvaluateExprAsBool(E->getRHS());
1066
1067  // Reaquire the RHS block, as there may be subblocks inserted.
1068  RHSBlock = Builder.GetInsertBlock();
1069  CGF.EmitBlock(ContBlock);
1070
1071  // Create a PHI node.  If we just evaluted the LHS condition, the result is
1072  // true.  If we evaluated both, the result is the RHS condition.
1073  llvm::PHINode *PN = Builder.CreatePHI(llvm::Type::Int1Ty, "lor");
1074  PN->reserveOperandSpace(2);
1075  PN->addIncoming(llvm::ConstantInt::getTrue(), OrigBlock);
1076  PN->addIncoming(RHSCond, RHSBlock);
1077
1078  // ZExt result to int.
1079  return Builder.CreateZExt(PN, CGF.LLVMIntTy, "lor.ext");
1080}
1081
1082Value *ScalarExprEmitter::VisitBinComma(const BinaryOperator *E) {
1083  CGF.EmitStmt(E->getLHS());
1084  return Visit(E->getRHS());
1085}
1086
1087//===----------------------------------------------------------------------===//
1088//                             Other Operators
1089//===----------------------------------------------------------------------===//
1090
1091Value *ScalarExprEmitter::
1092VisitConditionalOperator(const ConditionalOperator *E) {
1093  llvm::BasicBlock *LHSBlock = CGF.createBasicBlock("cond.?");
1094  llvm::BasicBlock *RHSBlock = CGF.createBasicBlock("cond.:");
1095  llvm::BasicBlock *ContBlock = CGF.createBasicBlock("cond.cont");
1096
1097  // Evaluate the conditional, then convert it to bool.  We do this explicitly
1098  // because we need the unconverted value if this is a GNU ?: expression with
1099  // missing middle value.
1100  Value *CondVal = CGF.EmitScalarExpr(E->getCond());
1101  Value *CondBoolVal =CGF.EmitScalarConversion(CondVal, E->getCond()->getType(),
1102                                               CGF.getContext().BoolTy);
1103  Builder.CreateCondBr(CondBoolVal, LHSBlock, RHSBlock);
1104
1105  CGF.EmitBlock(LHSBlock);
1106
1107  // Handle the GNU extension for missing LHS.
1108  Value *LHS;
1109  if (E->getLHS())
1110    LHS = Visit(E->getLHS());
1111  else    // Perform promotions, to handle cases like "short ?: int"
1112    LHS = EmitScalarConversion(CondVal, E->getCond()->getType(), E->getType());
1113
1114  Builder.CreateBr(ContBlock);
1115  LHSBlock = Builder.GetInsertBlock();
1116
1117  CGF.EmitBlock(RHSBlock);
1118
1119  Value *RHS = Visit(E->getRHS());
1120  Builder.CreateBr(ContBlock);
1121  RHSBlock = Builder.GetInsertBlock();
1122
1123  CGF.EmitBlock(ContBlock);
1124
1125  if (!LHS || !RHS) {
1126    assert(E->getType()->isVoidType() && "Non-void value should have a value");
1127    return 0;
1128  }
1129
1130  // Create a PHI node for the real part.
1131  llvm::PHINode *PN = Builder.CreatePHI(LHS->getType(), "cond");
1132  PN->reserveOperandSpace(2);
1133  PN->addIncoming(LHS, LHSBlock);
1134  PN->addIncoming(RHS, RHSBlock);
1135  return PN;
1136}
1137
1138Value *ScalarExprEmitter::VisitChooseExpr(ChooseExpr *E) {
1139  // Emit the LHS or RHS as appropriate.
1140  return
1141    Visit(E->isConditionTrue(CGF.getContext()) ? E->getLHS() : E->getRHS());
1142}
1143
1144Value *ScalarExprEmitter::VisitOverloadExpr(OverloadExpr *E) {
1145  return CGF.EmitCallExpr(E->getFn(), E->arg_begin(),
1146                          E->arg_end(CGF.getContext())).getScalarVal();
1147}
1148
1149Value *ScalarExprEmitter::VisitVAArgExpr(VAArgExpr *VE) {
1150  llvm::Value *ArgValue = EmitLValue(VE->getSubExpr()).getAddress();
1151
1152  llvm::Value *ArgPtr = CGF.EmitVAArg(ArgValue, VE->getType());
1153
1154  // If EmitVAArg fails, we fall back to the LLVM instruction.
1155  if (!ArgPtr)
1156    return Builder.CreateVAArg(ArgValue, ConvertType(VE->getType()));
1157
1158  // FIXME: volatile?
1159  return Builder.CreateLoad(ArgPtr);
1160}
1161
1162Value *ScalarExprEmitter::VisitObjCEncodeExpr(const ObjCEncodeExpr *E) {
1163  std::string str;
1164  CGF.getContext().getObjCEncodingForType(E->getEncodedType(), str);
1165
1166  llvm::Constant *C = llvm::ConstantArray::get(str);
1167  C = new llvm::GlobalVariable(C->getType(), true,
1168                               llvm::GlobalValue::InternalLinkage,
1169                               C, ".str", &CGF.CGM.getModule());
1170  llvm::Constant *Zero = llvm::Constant::getNullValue(llvm::Type::Int32Ty);
1171  llvm::Constant *Zeros[] = { Zero, Zero };
1172  C = llvm::ConstantExpr::getGetElementPtr(C, Zeros, 2);
1173
1174  return C;
1175}
1176
1177//===----------------------------------------------------------------------===//
1178//                         Entry Point into this File
1179//===----------------------------------------------------------------------===//
1180
1181/// EmitComplexExpr - Emit the computation of the specified expression of
1182/// complex type, ignoring the result.
1183Value *CodeGenFunction::EmitScalarExpr(const Expr *E) {
1184  assert(E && !hasAggregateLLVMType(E->getType()) &&
1185         "Invalid scalar expression to emit");
1186
1187  return ScalarExprEmitter(*this).Visit(const_cast<Expr*>(E));
1188}
1189
1190/// EmitScalarConversion - Emit a conversion from the specified type to the
1191/// specified destination type, both of which are LLVM scalar types.
1192Value *CodeGenFunction::EmitScalarConversion(Value *Src, QualType SrcTy,
1193                                             QualType DstTy) {
1194  assert(!hasAggregateLLVMType(SrcTy) && !hasAggregateLLVMType(DstTy) &&
1195         "Invalid scalar expression to emit");
1196  return ScalarExprEmitter(*this).EmitScalarConversion(Src, SrcTy, DstTy);
1197}
1198
1199/// EmitComplexToScalarConversion - Emit a conversion from the specified
1200/// complex type to the specified destination type, where the destination
1201/// type is an LLVM scalar type.
1202Value *CodeGenFunction::EmitComplexToScalarConversion(ComplexPairTy Src,
1203                                                      QualType SrcTy,
1204                                                      QualType DstTy) {
1205  assert(SrcTy->isAnyComplexType() && !hasAggregateLLVMType(DstTy) &&
1206         "Invalid complex -> scalar conversion");
1207  return ScalarExprEmitter(*this).EmitComplexToScalarConversion(Src, SrcTy,
1208                                                                DstTy);
1209}
1210
1211Value *CodeGenFunction::EmitShuffleVector(Value* V1, Value *V2, ...) {
1212  assert(V1->getType() == V2->getType() &&
1213         "Vector operands must be of the same type");
1214  unsigned NumElements =
1215    cast<llvm::VectorType>(V1->getType())->getNumElements();
1216
1217  va_list va;
1218  va_start(va, V2);
1219
1220  llvm::SmallVector<llvm::Constant*, 16> Args;
1221  for (unsigned i = 0; i < NumElements; i++) {
1222    int n = va_arg(va, int);
1223    assert(n >= 0 && n < (int)NumElements * 2 &&
1224           "Vector shuffle index out of bounds!");
1225    Args.push_back(llvm::ConstantInt::get(llvm::Type::Int32Ty, n));
1226  }
1227
1228  const char *Name = va_arg(va, const char *);
1229  va_end(va);
1230
1231  llvm::Constant *Mask = llvm::ConstantVector::get(&Args[0], NumElements);
1232
1233  return Builder.CreateShuffleVector(V1, V2, Mask, Name);
1234}
1235
1236llvm::Value *CodeGenFunction::EmitVector(llvm::Value * const *Vals,
1237                                         unsigned NumVals, bool isSplat) {
1238  llvm::Value *Vec
1239    = llvm::UndefValue::get(llvm::VectorType::get(Vals[0]->getType(), NumVals));
1240
1241  for (unsigned i = 0, e = NumVals; i != e; ++i) {
1242    llvm::Value *Val = isSplat ? Vals[0] : Vals[i];
1243    llvm::Value *Idx = llvm::ConstantInt::get(llvm::Type::Int32Ty, i);
1244    Vec = Builder.CreateInsertElement(Vec, Val, Idx, "tmp");
1245  }
1246
1247  return Vec;
1248}
1249