CGExprScalar.cpp revision 28665272c36cccb1014a6ea1217354b0519e2b59 
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 "CGObjCRuntime.h"
16#include "CodeGenModule.h"
17#include "clang/AST/ASTContext.h"
18#include "clang/AST/DeclObjC.h"
19#include "clang/AST/RecordLayout.h"
20#include "clang/AST/StmtVisitor.h"
21#include "clang/Basic/TargetInfo.h"
22#include "llvm/Constants.h"
23#include "llvm/Function.h"
24#include "llvm/GlobalVariable.h"
25#include "llvm/Intrinsics.h"
26#include "llvm/Module.h"
27#include "llvm/Support/Compiler.h"
28#include "llvm/Support/CFG.h"
29#include "llvm/Target/TargetData.h"
30#include <cstdarg>
31
32using namespace clang;
33using namespace CodeGen;
34using llvm::Value;
35
36//===----------------------------------------------------------------------===//
37//                         Scalar Expression Emitter
38//===----------------------------------------------------------------------===//
39
40struct BinOpInfo {
41  Value *LHS;
42  Value *RHS;
43  QualType Ty;  // Computation Type.
44  const BinaryOperator *E;
45};
46
47namespace {
48class VISIBILITY_HIDDEN ScalarExprEmitter
49  : public StmtVisitor<ScalarExprEmitter, Value*> {
50  CodeGenFunction &CGF;
51  CGBuilderTy &Builder;
52  bool IgnoreResultAssign;
53  llvm::LLVMContext &VMContext;
54public:
55
56  ScalarExprEmitter(CodeGenFunction &cgf, bool ira=false)
57    : CGF(cgf), Builder(CGF.Builder), IgnoreResultAssign(ira),
58      VMContext(cgf.getLLVMContext()) {
59  }
60
61  //===--------------------------------------------------------------------===//
62  //                               Utilities
63  //===--------------------------------------------------------------------===//
64
65  bool TestAndClearIgnoreResultAssign() {
66    bool I = IgnoreResultAssign;
67    IgnoreResultAssign = false;
68    return I;
69  }
70
71  const llvm::Type *ConvertType(QualType T) { return CGF.ConvertType(T); }
72  LValue EmitLValue(const Expr *E) { return CGF.EmitLValue(E); }
73
74  Value *EmitLoadOfLValue(LValue LV, QualType T) {
75    return CGF.EmitLoadOfLValue(LV, T).getScalarVal();
76  }
77
78  /// EmitLoadOfLValue - Given an expression with complex type that represents a
79  /// value l-value, this method emits the address of the l-value, then loads
80  /// and returns the result.
81  Value *EmitLoadOfLValue(const Expr *E) {
82    return EmitLoadOfLValue(EmitLValue(E), E->getType());
83  }
84
85  /// EmitConversionToBool - Convert the specified expression value to a
86  /// boolean (i1) truth value.  This is equivalent to "Val != 0".
87  Value *EmitConversionToBool(Value *Src, QualType DstTy);
88
89  /// EmitScalarConversion - Emit a conversion from the specified type to the
90  /// specified destination type, both of which are LLVM scalar types.
91  Value *EmitScalarConversion(Value *Src, QualType SrcTy, QualType DstTy);
92
93  /// EmitComplexToScalarConversion - Emit a conversion from the specified
94  /// complex type to the specified destination type, where the destination type
95  /// is an LLVM scalar type.
96  Value *EmitComplexToScalarConversion(CodeGenFunction::ComplexPairTy Src,
97                                       QualType SrcTy, QualType DstTy);
98
99  //===--------------------------------------------------------------------===//
100  //                            Visitor Methods
101  //===--------------------------------------------------------------------===//
102
103  Value *VisitStmt(Stmt *S) {
104    S->dump(CGF.getContext().getSourceManager());
105    assert(0 && "Stmt can't have complex result type!");
106    return 0;
107  }
108  Value *VisitExpr(Expr *S);
109
110  Value *VisitParenExpr(ParenExpr *PE) { return Visit(PE->getSubExpr()); }
111
112  // Leaves.
113  Value *VisitIntegerLiteral(const IntegerLiteral *E) {
114    return llvm::ConstantInt::get(VMContext, E->getValue());
115  }
116  Value *VisitFloatingLiteral(const FloatingLiteral *E) {
117    return llvm::ConstantFP::get(VMContext, E->getValue());
118  }
119  Value *VisitCharacterLiteral(const CharacterLiteral *E) {
120    return llvm::ConstantInt::get(ConvertType(E->getType()), E->getValue());
121  }
122  Value *VisitCXXBoolLiteralExpr(const CXXBoolLiteralExpr *E) {
123    return llvm::ConstantInt::get(ConvertType(E->getType()), E->getValue());
124  }
125  Value *VisitCXXZeroInitValueExpr(const CXXZeroInitValueExpr *E) {
126    return llvm::Constant::getNullValue(ConvertType(E->getType()));
127  }
128  Value *VisitGNUNullExpr(const GNUNullExpr *E) {
129    return llvm::Constant::getNullValue(ConvertType(E->getType()));
130  }
131  Value *VisitTypesCompatibleExpr(const TypesCompatibleExpr *E) {
132    return llvm::ConstantInt::get(ConvertType(E->getType()),
133                                  CGF.getContext().typesAreCompatible(
134                                    E->getArgType1(), E->getArgType2()));
135  }
136  Value *VisitSizeOfAlignOfExpr(const SizeOfAlignOfExpr *E);
137  Value *VisitAddrLabelExpr(const AddrLabelExpr *E) {
138    llvm::Value *V = CGF.GetAddrOfLabel(E->getLabel());
139    return Builder.CreateBitCast(V, ConvertType(E->getType()));
140  }
141
142  // l-values.
143  Value *VisitDeclRefExpr(DeclRefExpr *E) {
144    Expr::EvalResult Result;
145    if (E->Evaluate(Result, CGF.getContext()) && Result.Val.isInt()) {
146      assert(!Result.HasSideEffects && "Constant declref with side-effect?!");
147      return llvm::ConstantInt::get(VMContext, Result.Val.getInt());
148    }
149    return EmitLoadOfLValue(E);
150  }
151  Value *VisitObjCSelectorExpr(ObjCSelectorExpr *E) {
152    return CGF.EmitObjCSelectorExpr(E);
153  }
154  Value *VisitObjCProtocolExpr(ObjCProtocolExpr *E) {
155    return CGF.EmitObjCProtocolExpr(E);
156  }
157  Value *VisitObjCIvarRefExpr(ObjCIvarRefExpr *E) {
158    return EmitLoadOfLValue(E);
159  }
160  Value *VisitObjCPropertyRefExpr(ObjCPropertyRefExpr *E) {
161    return EmitLoadOfLValue(E);
162  }
163  Value *VisitObjCImplicitSetterGetterRefExpr(
164                        ObjCImplicitSetterGetterRefExpr *E) {
165    return EmitLoadOfLValue(E);
166  }
167  Value *VisitObjCMessageExpr(ObjCMessageExpr *E) {
168    return CGF.EmitObjCMessageExpr(E).getScalarVal();
169  }
170
171  Value *VisitArraySubscriptExpr(ArraySubscriptExpr *E);
172  Value *VisitShuffleVectorExpr(ShuffleVectorExpr *E);
173  Value *VisitMemberExpr(MemberExpr *E);
174  Value *VisitExtVectorElementExpr(Expr *E) { return EmitLoadOfLValue(E); }
175  Value *VisitCompoundLiteralExpr(CompoundLiteralExpr *E) {
176    return EmitLoadOfLValue(E);
177  }
178  Value *VisitStringLiteral(Expr *E)  { return EmitLValue(E).getAddress(); }
179  Value *VisitObjCEncodeExpr(const ObjCEncodeExpr *E) {
180     return EmitLValue(E).getAddress();
181  }
182
183  Value *VisitPredefinedExpr(Expr *E) { return EmitLValue(E).getAddress(); }
184
185  Value *VisitInitListExpr(InitListExpr *E);
186
187  Value *VisitImplicitValueInitExpr(const ImplicitValueInitExpr *E) {
188    return llvm::Constant::getNullValue(ConvertType(E->getType()));
189  }
190  Value *VisitCastExpr(const CastExpr *E) {
191    // Make sure to evaluate VLA bounds now so that we have them for later.
192    if (E->getType()->isVariablyModifiedType())
193      CGF.EmitVLASize(E->getType());
194
195    return EmitCastExpr(E);
196  }
197  Value *EmitCastExpr(const CastExpr *E);
198
199  Value *VisitCallExpr(const CallExpr *E) {
200    if (E->getCallReturnType()->isReferenceType())
201      return EmitLoadOfLValue(E);
202
203    return CGF.EmitCallExpr(E).getScalarVal();
204  }
205
206  Value *VisitStmtExpr(const StmtExpr *E);
207
208  Value *VisitBlockDeclRefExpr(const BlockDeclRefExpr *E);
209
210  // Unary Operators.
211  Value *VisitPrePostIncDec(const UnaryOperator *E, bool isInc, bool isPre);
212  Value *VisitUnaryPostDec(const UnaryOperator *E) {
213    return VisitPrePostIncDec(E, false, false);
214  }
215  Value *VisitUnaryPostInc(const UnaryOperator *E) {
216    return VisitPrePostIncDec(E, true, false);
217  }
218  Value *VisitUnaryPreDec(const UnaryOperator *E) {
219    return VisitPrePostIncDec(E, false, true);
220  }
221  Value *VisitUnaryPreInc(const UnaryOperator *E) {
222    return VisitPrePostIncDec(E, true, true);
223  }
224  Value *VisitUnaryAddrOf(const UnaryOperator *E) {
225    return EmitLValue(E->getSubExpr()).getAddress();
226  }
227  Value *VisitUnaryDeref(const Expr *E) { return EmitLoadOfLValue(E); }
228  Value *VisitUnaryPlus(const UnaryOperator *E) {
229    // This differs from gcc, though, most likely due to a bug in gcc.
230    TestAndClearIgnoreResultAssign();
231    return Visit(E->getSubExpr());
232  }
233  Value *VisitUnaryMinus    (const UnaryOperator *E);
234  Value *VisitUnaryNot      (const UnaryOperator *E);
235  Value *VisitUnaryLNot     (const UnaryOperator *E);
236  Value *VisitUnaryReal     (const UnaryOperator *E);
237  Value *VisitUnaryImag     (const UnaryOperator *E);
238  Value *VisitUnaryExtension(const UnaryOperator *E) {
239    return Visit(E->getSubExpr());
240  }
241  Value *VisitUnaryOffsetOf(const UnaryOperator *E);
242
243  // C++
244  Value *VisitCXXDefaultArgExpr(CXXDefaultArgExpr *DAE) {
245    return Visit(DAE->getExpr());
246  }
247  Value *VisitCXXThisExpr(CXXThisExpr *TE) {
248    return CGF.LoadCXXThis();
249  }
250
251  Value *VisitCXXExprWithTemporaries(CXXExprWithTemporaries *E) {
252    return CGF.EmitCXXExprWithTemporaries(E).getScalarVal();
253  }
254  Value *VisitCXXNewExpr(const CXXNewExpr *E) {
255    return CGF.EmitCXXNewExpr(E);
256  }
257  Value *VisitCXXDeleteExpr(const CXXDeleteExpr *E) {
258    CGF.EmitCXXDeleteExpr(E);
259    return 0;
260  }
261
262  Value *VisitCXXPseudoDestructorExpr(const CXXPseudoDestructorExpr *E) {
263    // C++ [expr.pseudo]p1:
264    //   The result shall only be used as the operand for the function call
265    //   operator (), and the result of such a call has type void. The only
266    //   effect is the evaluation of the postfix-expression before the dot or
267    //   arrow.
268    CGF.EmitScalarExpr(E->getBase());
269    return 0;
270  }
271
272  Value *VisitCXXNullPtrLiteralExpr(const CXXNullPtrLiteralExpr *E) {
273    return llvm::Constant::getNullValue(ConvertType(E->getType()));
274  }
275
276  Value *VisitCXXThrowExpr(const CXXThrowExpr *E) {
277    CGF.EmitCXXThrowExpr(E);
278    return 0;
279  }
280
281  // Binary Operators.
282  Value *EmitMul(const BinOpInfo &Ops) {
283    if (CGF.getContext().getLangOptions().OverflowChecking
284        && Ops.Ty->isSignedIntegerType())
285      return EmitOverflowCheckedBinOp(Ops);
286    if (Ops.LHS->getType()->isFPOrFPVector())
287      return Builder.CreateFMul(Ops.LHS, Ops.RHS, "mul");
288    return Builder.CreateMul(Ops.LHS, Ops.RHS, "mul");
289  }
290  /// Create a binary op that checks for overflow.
291  /// Currently only supports +, - and *.
292  Value *EmitOverflowCheckedBinOp(const BinOpInfo &Ops);
293  Value *EmitDiv(const BinOpInfo &Ops);
294  Value *EmitRem(const BinOpInfo &Ops);
295  Value *EmitAdd(const BinOpInfo &Ops);
296  Value *EmitSub(const BinOpInfo &Ops);
297  Value *EmitShl(const BinOpInfo &Ops);
298  Value *EmitShr(const BinOpInfo &Ops);
299  Value *EmitAnd(const BinOpInfo &Ops) {
300    return Builder.CreateAnd(Ops.LHS, Ops.RHS, "and");
301  }
302  Value *EmitXor(const BinOpInfo &Ops) {
303    return Builder.CreateXor(Ops.LHS, Ops.RHS, "xor");
304  }
305  Value *EmitOr (const BinOpInfo &Ops) {
306    return Builder.CreateOr(Ops.LHS, Ops.RHS, "or");
307  }
308
309  BinOpInfo EmitBinOps(const BinaryOperator *E);
310  Value *EmitCompoundAssign(const CompoundAssignOperator *E,
311                            Value *(ScalarExprEmitter::*F)(const BinOpInfo &));
312
313  // Binary operators and binary compound assignment operators.
314#define HANDLEBINOP(OP) \
315  Value *VisitBin ## OP(const BinaryOperator *E) {                         \
316    return Emit ## OP(EmitBinOps(E));                                      \
317  }                                                                        \
318  Value *VisitBin ## OP ## Assign(const CompoundAssignOperator *E) {       \
319    return EmitCompoundAssign(E, &ScalarExprEmitter::Emit ## OP);          \
320  }
321  HANDLEBINOP(Mul);
322  HANDLEBINOP(Div);
323  HANDLEBINOP(Rem);
324  HANDLEBINOP(Add);
325  HANDLEBINOP(Sub);
326  HANDLEBINOP(Shl);
327  HANDLEBINOP(Shr);
328  HANDLEBINOP(And);
329  HANDLEBINOP(Xor);
330  HANDLEBINOP(Or);
331#undef HANDLEBINOP
332
333  // Comparisons.
334  Value *EmitCompare(const BinaryOperator *E, unsigned UICmpOpc,
335                     unsigned SICmpOpc, unsigned FCmpOpc);
336#define VISITCOMP(CODE, UI, SI, FP) \
337    Value *VisitBin##CODE(const BinaryOperator *E) { \
338      return EmitCompare(E, llvm::ICmpInst::UI, llvm::ICmpInst::SI, \
339                         llvm::FCmpInst::FP); }
340  VISITCOMP(LT, ICMP_ULT, ICMP_SLT, FCMP_OLT);
341  VISITCOMP(GT, ICMP_UGT, ICMP_SGT, FCMP_OGT);
342  VISITCOMP(LE, ICMP_ULE, ICMP_SLE, FCMP_OLE);
343  VISITCOMP(GE, ICMP_UGE, ICMP_SGE, FCMP_OGE);
344  VISITCOMP(EQ, ICMP_EQ , ICMP_EQ , FCMP_OEQ);
345  VISITCOMP(NE, ICMP_NE , ICMP_NE , FCMP_UNE);
346#undef VISITCOMP
347
348  Value *VisitBinAssign     (const BinaryOperator *E);
349
350  Value *VisitBinLAnd       (const BinaryOperator *E);
351  Value *VisitBinLOr        (const BinaryOperator *E);
352  Value *VisitBinComma      (const BinaryOperator *E);
353
354  Value *VisitBinPtrMemD(const Expr *E) { return EmitLoadOfLValue(E); }
355  Value *VisitBinPtrMemI(const Expr *E) { return EmitLoadOfLValue(E); }
356
357  // Other Operators.
358  Value *VisitBlockExpr(const BlockExpr *BE);
359  Value *VisitConditionalOperator(const ConditionalOperator *CO);
360  Value *VisitChooseExpr(ChooseExpr *CE);
361  Value *VisitVAArgExpr(VAArgExpr *VE);
362  Value *VisitObjCStringLiteral(const ObjCStringLiteral *E) {
363    return CGF.EmitObjCStringLiteral(E);
364  }
365};
366}  // end anonymous namespace.
367
368//===----------------------------------------------------------------------===//
369//                                Utilities
370//===----------------------------------------------------------------------===//
371
372/// EmitConversionToBool - Convert the specified expression value to a
373/// boolean (i1) truth value.  This is equivalent to "Val != 0".
374Value *ScalarExprEmitter::EmitConversionToBool(Value *Src, QualType SrcType) {
375  assert(SrcType.isCanonical() && "EmitScalarConversion strips typedefs");
376
377  if (SrcType->isRealFloatingType()) {
378    // Compare against 0.0 for fp scalars.
379    llvm::Value *Zero = llvm::Constant::getNullValue(Src->getType());
380    return Builder.CreateFCmpUNE(Src, Zero, "tobool");
381  }
382
383  if (SrcType->isMemberPointerType()) {
384    // FIXME: This is ABI specific.
385
386    // Compare against -1.
387    llvm::Value *NegativeOne = llvm::Constant::getAllOnesValue(Src->getType());
388    return Builder.CreateICmpNE(Src, NegativeOne, "tobool");
389  }
390
391  assert((SrcType->isIntegerType() || isa<llvm::PointerType>(Src->getType())) &&
392         "Unknown scalar type to convert");
393
394  // Because of the type rules of C, we often end up computing a logical value,
395  // then zero extending it to int, then wanting it as a logical value again.
396  // Optimize this common case.
397  if (llvm::ZExtInst *ZI = dyn_cast<llvm::ZExtInst>(Src)) {
398    if (ZI->getOperand(0)->getType() ==
399        llvm::Type::getInt1Ty(CGF.getLLVMContext())) {
400      Value *Result = ZI->getOperand(0);
401      // If there aren't any more uses, zap the instruction to save space.
402      // Note that there can be more uses, for example if this
403      // is the result of an assignment.
404      if (ZI->use_empty())
405        ZI->eraseFromParent();
406      return Result;
407    }
408  }
409
410  // Compare against an integer or pointer null.
411  llvm::Value *Zero = llvm::Constant::getNullValue(Src->getType());
412  return Builder.CreateICmpNE(Src, Zero, "tobool");
413}
414
415/// EmitScalarConversion - Emit a conversion from the specified type to the
416/// specified destination type, both of which are LLVM scalar types.
417Value *ScalarExprEmitter::EmitScalarConversion(Value *Src, QualType SrcType,
418                                               QualType DstType) {
419  SrcType = CGF.getContext().getCanonicalType(SrcType);
420  DstType = CGF.getContext().getCanonicalType(DstType);
421  if (SrcType == DstType) return Src;
422
423  if (DstType->isVoidType()) return 0;
424
425  llvm::LLVMContext &VMContext = CGF.getLLVMContext();
426
427  // Handle conversions to bool first, they are special: comparisons against 0.
428  if (DstType->isBooleanType())
429    return EmitConversionToBool(Src, SrcType);
430
431  const llvm::Type *DstTy = ConvertType(DstType);
432
433  // Ignore conversions like int -> uint.
434  if (Src->getType() == DstTy)
435    return Src;
436
437  // Handle pointer conversions next: pointers can only be converted to/from
438  // other pointers and integers. Check for pointer types in terms of LLVM, as
439  // some native types (like Obj-C id) may map to a pointer type.
440  if (isa<llvm::PointerType>(DstTy)) {
441    // The source value may be an integer, or a pointer.
442    if (isa<llvm::PointerType>(Src->getType()))
443      return Builder.CreateBitCast(Src, DstTy, "conv");
444
445    assert(SrcType->isIntegerType() && "Not ptr->ptr or int->ptr conversion?");
446    // First, convert to the correct width so that we control the kind of
447    // extension.
448    const llvm::Type *MiddleTy =
449          llvm::IntegerType::get(VMContext, CGF.LLVMPointerWidth);
450    bool InputSigned = SrcType->isSignedIntegerType();
451    llvm::Value* IntResult =
452        Builder.CreateIntCast(Src, MiddleTy, InputSigned, "conv");
453    // Then, cast to pointer.
454    return Builder.CreateIntToPtr(IntResult, DstTy, "conv");
455  }
456
457  if (isa<llvm::PointerType>(Src->getType())) {
458    // Must be an ptr to int cast.
459    assert(isa<llvm::IntegerType>(DstTy) && "not ptr->int?");
460    return Builder.CreatePtrToInt(Src, DstTy, "conv");
461  }
462
463  // A scalar can be splatted to an extended vector of the same element type
464  if (DstType->isExtVectorType() && !SrcType->isVectorType()) {
465    // Cast the scalar to element type
466    QualType EltTy = DstType->getAs<ExtVectorType>()->getElementType();
467    llvm::Value *Elt = EmitScalarConversion(Src, SrcType, EltTy);
468
469    // Insert the element in element zero of an undef vector
470    llvm::Value *UnV = llvm::UndefValue::get(DstTy);
471    llvm::Value *Idx =
472        llvm::ConstantInt::get(llvm::Type::getInt32Ty(VMContext), 0);
473    UnV = Builder.CreateInsertElement(UnV, Elt, Idx, "tmp");
474
475    // Splat the element across to all elements
476    llvm::SmallVector<llvm::Constant*, 16> Args;
477    unsigned NumElements = cast<llvm::VectorType>(DstTy)->getNumElements();
478    for (unsigned i = 0; i < NumElements; i++)
479      Args.push_back(llvm::ConstantInt::get(
480                                        llvm::Type::getInt32Ty(VMContext), 0));
481
482    llvm::Constant *Mask = llvm::ConstantVector::get(&Args[0], NumElements);
483    llvm::Value *Yay = Builder.CreateShuffleVector(UnV, UnV, Mask, "splat");
484    return Yay;
485  }
486
487  // Allow bitcast from vector to integer/fp of the same size.
488  if (isa<llvm::VectorType>(Src->getType()) ||
489      isa<llvm::VectorType>(DstTy))
490    return Builder.CreateBitCast(Src, DstTy, "conv");
491
492  // Finally, we have the arithmetic types: real int/float.
493  if (isa<llvm::IntegerType>(Src->getType())) {
494    bool InputSigned = SrcType->isSignedIntegerType();
495    if (isa<llvm::IntegerType>(DstTy))
496      return Builder.CreateIntCast(Src, DstTy, InputSigned, "conv");
497    else if (InputSigned)
498      return Builder.CreateSIToFP(Src, DstTy, "conv");
499    else
500      return Builder.CreateUIToFP(Src, DstTy, "conv");
501  }
502
503  assert(Src->getType()->isFloatingPoint() && "Unknown real conversion");
504  if (isa<llvm::IntegerType>(DstTy)) {
505    if (DstType->isSignedIntegerType())
506      return Builder.CreateFPToSI(Src, DstTy, "conv");
507    else
508      return Builder.CreateFPToUI(Src, DstTy, "conv");
509  }
510
511  assert(DstTy->isFloatingPoint() && "Unknown real conversion");
512  if (DstTy->getTypeID() < Src->getType()->getTypeID())
513    return Builder.CreateFPTrunc(Src, DstTy, "conv");
514  else
515    return Builder.CreateFPExt(Src, DstTy, "conv");
516}
517
518/// EmitComplexToScalarConversion - Emit a conversion from the specified complex
519/// type to the specified destination type, where the destination type is an
520/// LLVM scalar type.
521Value *ScalarExprEmitter::
522EmitComplexToScalarConversion(CodeGenFunction::ComplexPairTy Src,
523                              QualType SrcTy, QualType DstTy) {
524  // Get the source element type.
525  SrcTy = SrcTy->getAs<ComplexType>()->getElementType();
526
527  // Handle conversions to bool first, they are special: comparisons against 0.
528  if (DstTy->isBooleanType()) {
529    //  Complex != 0  -> (Real != 0) | (Imag != 0)
530    Src.first  = EmitScalarConversion(Src.first, SrcTy, DstTy);
531    Src.second = EmitScalarConversion(Src.second, SrcTy, DstTy);
532    return Builder.CreateOr(Src.first, Src.second, "tobool");
533  }
534
535  // C99 6.3.1.7p2: "When a value of complex type is converted to a real type,
536  // the imaginary part of the complex value is discarded and the value of the
537  // real part is converted according to the conversion rules for the
538  // corresponding real type.
539  return EmitScalarConversion(Src.first, SrcTy, DstTy);
540}
541
542
543//===----------------------------------------------------------------------===//
544//                            Visitor Methods
545//===----------------------------------------------------------------------===//
546
547Value *ScalarExprEmitter::VisitExpr(Expr *E) {
548  CGF.ErrorUnsupported(E, "scalar expression");
549  if (E->getType()->isVoidType())
550    return 0;
551  return llvm::UndefValue::get(CGF.ConvertType(E->getType()));
552}
553
554Value *ScalarExprEmitter::VisitShuffleVectorExpr(ShuffleVectorExpr *E) {
555  llvm::SmallVector<llvm::Constant*, 32> indices;
556  for (unsigned i = 2; i < E->getNumSubExprs(); i++) {
557    indices.push_back(cast<llvm::Constant>(CGF.EmitScalarExpr(E->getExpr(i))));
558  }
559  Value* V1 = CGF.EmitScalarExpr(E->getExpr(0));
560  Value* V2 = CGF.EmitScalarExpr(E->getExpr(1));
561  Value* SV = llvm::ConstantVector::get(indices.begin(), indices.size());
562  return Builder.CreateShuffleVector(V1, V2, SV, "shuffle");
563}
564Value *ScalarExprEmitter::VisitMemberExpr(MemberExpr *E) {
565  Expr::EvalResult Result;
566  if (E->Evaluate(Result, CGF.getContext()) && Result.Val.isInt()) {
567    if (E->isArrow())
568      CGF.EmitScalarExpr(E->getBase());
569    else
570      EmitLValue(E->getBase());
571    return llvm::ConstantInt::get(VMContext, Result.Val.getInt());
572  }
573  return EmitLoadOfLValue(E);
574}
575
576Value *ScalarExprEmitter::VisitArraySubscriptExpr(ArraySubscriptExpr *E) {
577  TestAndClearIgnoreResultAssign();
578
579  // Emit subscript expressions in rvalue context's.  For most cases, this just
580  // loads the lvalue formed by the subscript expr.  However, we have to be
581  // careful, because the base of a vector subscript is occasionally an rvalue,
582  // so we can't get it as an lvalue.
583  if (!E->getBase()->getType()->isVectorType())
584    return EmitLoadOfLValue(E);
585
586  // Handle the vector case.  The base must be a vector, the index must be an
587  // integer value.
588  Value *Base = Visit(E->getBase());
589  Value *Idx  = Visit(E->getIdx());
590  bool IdxSigned = E->getIdx()->getType()->isSignedIntegerType();
591  Idx = Builder.CreateIntCast(Idx,
592                              llvm::Type::getInt32Ty(CGF.getLLVMContext()),
593                              IdxSigned,
594                              "vecidxcast");
595  return Builder.CreateExtractElement(Base, Idx, "vecext");
596}
597
598static llvm::Constant *getMaskElt(llvm::ShuffleVectorInst *SVI, unsigned Idx,
599                                  unsigned Off, const llvm::Type *I32Ty) {
600  int MV = SVI->getMaskValue(Idx);
601  if (MV == -1)
602    return llvm::UndefValue::get(I32Ty);
603  return llvm::ConstantInt::get(I32Ty, Off+MV);
604}
605
606Value *ScalarExprEmitter::VisitInitListExpr(InitListExpr *E) {
607  bool Ignore = TestAndClearIgnoreResultAssign();
608  (void)Ignore;
609  assert (Ignore == false && "init list ignored");
610  unsigned NumInitElements = E->getNumInits();
611
612  if (E->hadArrayRangeDesignator())
613    CGF.ErrorUnsupported(E, "GNU array range designator extension");
614
615  const llvm::VectorType *VType =
616    dyn_cast<llvm::VectorType>(ConvertType(E->getType()));
617
618  // We have a scalar in braces. Just use the first element.
619  if (!VType)
620    return Visit(E->getInit(0));
621
622  unsigned ResElts = VType->getNumElements();
623  const llvm::Type *I32Ty = llvm::Type::getInt32Ty(CGF.getLLVMContext());
624
625  // Loop over initializers collecting the Value for each, and remembering
626  // whether the source was swizzle (ExtVectorElementExpr).  This will allow
627  // us to fold the shuffle for the swizzle into the shuffle for the vector
628  // initializer, since LLVM optimizers generally do not want to touch
629  // shuffles.
630  unsigned CurIdx = 0;
631  bool VIsUndefShuffle = false;
632  llvm::Value *V = llvm::UndefValue::get(VType);
633  for (unsigned i = 0; i != NumInitElements; ++i) {
634    Expr *IE = E->getInit(i);
635    Value *Init = Visit(IE);
636    llvm::SmallVector<llvm::Constant*, 16> Args;
637
638    const llvm::VectorType *VVT = dyn_cast<llvm::VectorType>(Init->getType());
639
640    // Handle scalar elements.  If the scalar initializer is actually one
641    // element of a different vector of the same width, use shuffle instead of
642    // extract+insert.
643    if (!VVT) {
644      if (isa<ExtVectorElementExpr>(IE)) {
645        llvm::ExtractElementInst *EI = cast<llvm::ExtractElementInst>(Init);
646
647        if (EI->getVectorOperandType()->getNumElements() == ResElts) {
648          llvm::ConstantInt *C = cast<llvm::ConstantInt>(EI->getIndexOperand());
649          Value *LHS = 0, *RHS = 0;
650          if (CurIdx == 0) {
651            // insert into undef -> shuffle (src, undef)
652            Args.push_back(C);
653            for (unsigned j = 1; j != ResElts; ++j)
654              Args.push_back(llvm::UndefValue::get(I32Ty));
655
656            LHS = EI->getVectorOperand();
657            RHS = V;
658            VIsUndefShuffle = true;
659          } else if (VIsUndefShuffle) {
660            // insert into undefshuffle && size match -> shuffle (v, src)
661            llvm::ShuffleVectorInst *SVV = cast<llvm::ShuffleVectorInst>(V);
662            for (unsigned j = 0; j != CurIdx; ++j)
663              Args.push_back(getMaskElt(SVV, j, 0, I32Ty));
664            Args.push_back(llvm::ConstantInt::get(I32Ty,
665                                                  ResElts + C->getZExtValue()));
666            for (unsigned j = CurIdx + 1; j != ResElts; ++j)
667              Args.push_back(llvm::UndefValue::get(I32Ty));
668
669            LHS = cast<llvm::ShuffleVectorInst>(V)->getOperand(0);
670            RHS = EI->getVectorOperand();
671            VIsUndefShuffle = false;
672          }
673          if (!Args.empty()) {
674            llvm::Constant *Mask = llvm::ConstantVector::get(&Args[0], ResElts);
675            V = Builder.CreateShuffleVector(LHS, RHS, Mask);
676            ++CurIdx;
677            continue;
678          }
679        }
680      }
681      Value *Idx = llvm::ConstantInt::get(I32Ty, CurIdx);
682      V = Builder.CreateInsertElement(V, Init, Idx, "vecinit");
683      VIsUndefShuffle = false;
684      ++CurIdx;
685      continue;
686    }
687
688    unsigned InitElts = VVT->getNumElements();
689
690    // If the initializer is an ExtVecEltExpr (a swizzle), and the swizzle's
691    // input is the same width as the vector being constructed, generate an
692    // optimized shuffle of the swizzle input into the result.
693    unsigned Offset = (CurIdx == 0) ? 0 : ResElts;
694    if (isa<ExtVectorElementExpr>(IE)) {
695      llvm::ShuffleVectorInst *SVI = cast<llvm::ShuffleVectorInst>(Init);
696      Value *SVOp = SVI->getOperand(0);
697      const llvm::VectorType *OpTy = cast<llvm::VectorType>(SVOp->getType());
698
699      if (OpTy->getNumElements() == ResElts) {
700        for (unsigned j = 0; j != CurIdx; ++j) {
701          // If the current vector initializer is a shuffle with undef, merge
702          // this shuffle directly into it.
703          if (VIsUndefShuffle) {
704            Args.push_back(getMaskElt(cast<llvm::ShuffleVectorInst>(V), j, 0,
705                                      I32Ty));
706          } else {
707            Args.push_back(llvm::ConstantInt::get(I32Ty, j));
708          }
709        }
710        for (unsigned j = 0, je = InitElts; j != je; ++j)
711          Args.push_back(getMaskElt(SVI, j, Offset, I32Ty));
712        for (unsigned j = CurIdx + InitElts; j != ResElts; ++j)
713          Args.push_back(llvm::UndefValue::get(I32Ty));
714
715        if (VIsUndefShuffle)
716          V = cast<llvm::ShuffleVectorInst>(V)->getOperand(0);
717
718        Init = SVOp;
719      }
720    }
721
722    // Extend init to result vector length, and then shuffle its contribution
723    // to the vector initializer into V.
724    if (Args.empty()) {
725      for (unsigned j = 0; j != InitElts; ++j)
726        Args.push_back(llvm::ConstantInt::get(I32Ty, j));
727      for (unsigned j = InitElts; j != ResElts; ++j)
728        Args.push_back(llvm::UndefValue::get(I32Ty));
729      llvm::Constant *Mask = llvm::ConstantVector::get(&Args[0], ResElts);
730      Init = Builder.CreateShuffleVector(Init, llvm::UndefValue::get(VVT),
731                                         Mask, "vext");
732
733      Args.clear();
734      for (unsigned j = 0; j != CurIdx; ++j)
735        Args.push_back(llvm::ConstantInt::get(I32Ty, j));
736      for (unsigned j = 0; j != InitElts; ++j)
737        Args.push_back(llvm::ConstantInt::get(I32Ty, j+Offset));
738      for (unsigned j = CurIdx + InitElts; j != ResElts; ++j)
739        Args.push_back(llvm::UndefValue::get(I32Ty));
740    }
741
742    // If V is undef, make sure it ends up on the RHS of the shuffle to aid
743    // merging subsequent shuffles into this one.
744    if (CurIdx == 0)
745      std::swap(V, Init);
746    llvm::Constant *Mask = llvm::ConstantVector::get(&Args[0], ResElts);
747    V = Builder.CreateShuffleVector(V, Init, Mask, "vecinit");
748    VIsUndefShuffle = isa<llvm::UndefValue>(Init);
749    CurIdx += InitElts;
750  }
751
752  // FIXME: evaluate codegen vs. shuffling against constant null vector.
753  // Emit remaining default initializers.
754  const llvm::Type *EltTy = VType->getElementType();
755
756  // Emit remaining default initializers
757  for (/* Do not initialize i*/; CurIdx < ResElts; ++CurIdx) {
758    Value *Idx = llvm::ConstantInt::get(I32Ty, CurIdx);
759    llvm::Value *Init = llvm::Constant::getNullValue(EltTy);
760    V = Builder.CreateInsertElement(V, Init, Idx, "vecinit");
761  }
762  return V;
763}
764
765static bool ShouldNullCheckClassCastValue(const CastExpr *CE) {
766  const Expr *E = CE->getSubExpr();
767
768  if (isa<CXXThisExpr>(E)) {
769    // We always assume that 'this' is never null.
770    return false;
771  }
772
773  if (const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(CE)) {
774    // And that lvalue casts are never null.
775    if (ICE->isLvalueCast())
776      return false;
777  }
778
779  return true;
780}
781
782// VisitCastExpr - Emit code for an explicit or implicit cast.  Implicit casts
783// have to handle a more broad range of conversions than explicit casts, as they
784// handle things like function to ptr-to-function decay etc.
785Value *ScalarExprEmitter::EmitCastExpr(const CastExpr *CE) {
786  const Expr *E = CE->getSubExpr();
787  QualType DestTy = CE->getType();
788  CastExpr::CastKind Kind = CE->getCastKind();
789
790  if (!DestTy->isVoidType())
791    TestAndClearIgnoreResultAssign();
792
793  switch (Kind) {
794  default:
795    //return CGF.ErrorUnsupported(E, "type of cast");
796    break;
797
798  case CastExpr::CK_Unknown:
799    //assert(0 && "Unknown cast kind!");
800    break;
801
802  case CastExpr::CK_BitCast: {
803    Value *Src = Visit(const_cast<Expr*>(E));
804    return Builder.CreateBitCast(Src, ConvertType(DestTy));
805  }
806  case CastExpr::CK_NoOp:
807    return Visit(const_cast<Expr*>(E));
808
809  case CastExpr::CK_BaseToDerived: {
810    const CXXRecordDecl *BaseClassDecl =
811      E->getType()->getCXXRecordDeclForPointerType();
812    const CXXRecordDecl *DerivedClassDecl =
813      DestTy->getCXXRecordDeclForPointerType();
814
815    Value *Src = Visit(const_cast<Expr*>(E));
816
817    bool NullCheckValue = ShouldNullCheckClassCastValue(CE);
818    return CGF.GetAddressOfDerivedClass(Src, BaseClassDecl, DerivedClassDecl,
819                                        NullCheckValue);
820  }
821
822  case CastExpr::CK_DerivedToBase: {
823    const RecordType *DerivedClassTy =
824      E->getType()->getAs<PointerType>()->getPointeeType()->getAs<RecordType>();
825    CXXRecordDecl *DerivedClassDecl =
826      cast<CXXRecordDecl>(DerivedClassTy->getDecl());
827
828    const RecordType *BaseClassTy =
829      DestTy->getAs<PointerType>()->getPointeeType()->getAs<RecordType>();
830    CXXRecordDecl *BaseClassDecl = cast<CXXRecordDecl>(BaseClassTy->getDecl());
831
832    Value *Src = Visit(const_cast<Expr*>(E));
833
834    bool NullCheckValue = ShouldNullCheckClassCastValue(CE);
835    return CGF.GetAddressOfBaseClass(Src, DerivedClassDecl, BaseClassDecl,
836                                     NullCheckValue);
837  }
838  case CastExpr::CK_ToUnion: {
839    assert(0 && "Should be unreachable!");
840    break;
841  }
842  case CastExpr::CK_ArrayToPointerDecay: {
843    assert(E->getType()->isArrayType() &&
844           "Array to pointer decay must have array source type!");
845
846    Value *V = EmitLValue(E).getAddress();  // Bitfields can't be arrays.
847
848    // Note that VLA pointers are always decayed, so we don't need to do
849    // anything here.
850    if (!E->getType()->isVariableArrayType()) {
851      assert(isa<llvm::PointerType>(V->getType()) && "Expected pointer");
852      assert(isa<llvm::ArrayType>(cast<llvm::PointerType>(V->getType())
853                                 ->getElementType()) &&
854             "Expected pointer to array");
855      V = Builder.CreateStructGEP(V, 0, "arraydecay");
856    }
857
858    return V;
859  }
860  case CastExpr::CK_FunctionToPointerDecay:
861    return EmitLValue(E).getAddress();
862
863  case CastExpr::CK_NullToMemberPointer:
864    return CGF.CGM.EmitNullConstant(DestTy);
865
866  case CastExpr::CK_IntegralToPointer: {
867    Value *Src = Visit(const_cast<Expr*>(E));
868
869    // First, convert to the correct width so that we control the kind of
870    // extension.
871    const llvm::Type *MiddleTy =
872      llvm::IntegerType::get(VMContext, CGF.LLVMPointerWidth);
873    bool InputSigned = E->getType()->isSignedIntegerType();
874    llvm::Value* IntResult =
875      Builder.CreateIntCast(Src, MiddleTy, InputSigned, "conv");
876
877    return Builder.CreateIntToPtr(IntResult, ConvertType(DestTy));
878  }
879
880  case CastExpr::CK_PointerToIntegral: {
881    Value *Src = Visit(const_cast<Expr*>(E));
882    return Builder.CreatePtrToInt(Src, ConvertType(DestTy));
883  }
884
885  case CastExpr::CK_ToVoid: {
886    CGF.EmitAnyExpr(E, 0, false, true);
887    return 0;
888  }
889
890  case CastExpr::CK_Dynamic: {
891    Value *V = Visit(const_cast<Expr*>(E));
892    const CXXDynamicCastExpr *DCE = cast<CXXDynamicCastExpr>(CE);
893    return CGF.EmitDynamicCast(V, DCE);
894  }
895
896  case CastExpr::CK_VectorSplat: {
897    const llvm::Type *DstTy = ConvertType(DestTy);
898    Value *Elt = Visit(const_cast<Expr*>(E));
899
900    // Insert the element in element zero of an undef vector
901    llvm::Value *UnV = llvm::UndefValue::get(DstTy);
902    llvm::Value *Idx =
903        llvm::ConstantInt::get(llvm::Type::getInt32Ty(VMContext), 0);
904    UnV = Builder.CreateInsertElement(UnV, Elt, Idx, "tmp");
905
906    // Splat the element across to all elements
907    llvm::SmallVector<llvm::Constant*, 16> Args;
908    unsigned NumElements = cast<llvm::VectorType>(DstTy)->getNumElements();
909    for (unsigned i = 0; i < NumElements; i++)
910      Args.push_back(llvm::ConstantInt::get(
911                                        llvm::Type::getInt32Ty(VMContext), 0));
912
913    llvm::Constant *Mask = llvm::ConstantVector::get(&Args[0], NumElements);
914    llvm::Value *Yay = Builder.CreateShuffleVector(UnV, UnV, Mask, "splat");
915    return Yay;
916  }
917
918  case CastExpr::CK_MemberPointerToBoolean: {
919    const MemberPointerType* T = E->getType()->getAs<MemberPointerType>();
920
921    if (T->getPointeeType()->isFunctionType()) {
922      // We have a member function pointer.
923      llvm::Value *Ptr = CGF.CreateTempAlloca(ConvertType(E->getType()));
924
925      CGF.EmitAggExpr(E, Ptr, /*VolatileDest=*/false);
926
927      // Get the pointer.
928      llvm::Value *FuncPtr = Builder.CreateStructGEP(Ptr, 0, "src.ptr");
929      FuncPtr = Builder.CreateLoad(FuncPtr);
930
931      llvm::Value *IsNotNull =
932        Builder.CreateICmpNE(FuncPtr,
933                             llvm::Constant::getNullValue(FuncPtr->getType()),
934                             "tobool");
935
936      return IsNotNull;
937    }
938
939    // We have a regular member pointer.
940    Value *Ptr = Visit(const_cast<Expr*>(E));
941    llvm::Value *IsNotNull =
942      Builder.CreateICmpNE(Ptr, CGF.CGM.EmitNullConstant(E->getType()),
943                           "tobool");
944    return IsNotNull;
945  }
946
947  }
948
949  // Handle cases where the source is an non-complex type.
950
951  if (!CGF.hasAggregateLLVMType(E->getType())) {
952    Value *Src = Visit(const_cast<Expr*>(E));
953
954    // Use EmitScalarConversion to perform the conversion.
955    return EmitScalarConversion(Src, E->getType(), DestTy);
956  }
957
958  if (E->getType()->isAnyComplexType()) {
959    // Handle cases where the source is a complex type.
960    bool IgnoreImag = true;
961    bool IgnoreImagAssign = true;
962    bool IgnoreReal = IgnoreResultAssign;
963    bool IgnoreRealAssign = IgnoreResultAssign;
964    if (DestTy->isBooleanType())
965      IgnoreImagAssign = IgnoreImag = false;
966    else if (DestTy->isVoidType()) {
967      IgnoreReal = IgnoreImag = false;
968      IgnoreRealAssign = IgnoreImagAssign = true;
969    }
970    CodeGenFunction::ComplexPairTy V
971      = CGF.EmitComplexExpr(E, IgnoreReal, IgnoreImag, IgnoreRealAssign,
972                            IgnoreImagAssign);
973    return EmitComplexToScalarConversion(V, E->getType(), DestTy);
974  }
975
976  // Okay, this is a cast from an aggregate.  It must be a cast to void.  Just
977  // evaluate the result and return.
978  CGF.EmitAggExpr(E, 0, false, true);
979  return 0;
980}
981
982Value *ScalarExprEmitter::VisitStmtExpr(const StmtExpr *E) {
983  return CGF.EmitCompoundStmt(*E->getSubStmt(),
984                              !E->getType()->isVoidType()).getScalarVal();
985}
986
987Value *ScalarExprEmitter::VisitBlockDeclRefExpr(const BlockDeclRefExpr *E) {
988  llvm::Value *V = CGF.GetAddrOfBlockDecl(E);
989  if (E->getType().isObjCGCWeak())
990    return CGF.CGM.getObjCRuntime().EmitObjCWeakRead(CGF, V);
991  return Builder.CreateLoad(V, false, "tmp");
992}
993
994//===----------------------------------------------------------------------===//
995//                             Unary Operators
996//===----------------------------------------------------------------------===//
997
998Value *ScalarExprEmitter::VisitPrePostIncDec(const UnaryOperator *E,
999                                             bool isInc, bool isPre) {
1000  LValue LV = EmitLValue(E->getSubExpr());
1001  QualType ValTy = E->getSubExpr()->getType();
1002  Value *InVal = CGF.EmitLoadOfLValue(LV, ValTy).getScalarVal();
1003
1004  llvm::LLVMContext &VMContext = CGF.getLLVMContext();
1005
1006  int AmountVal = isInc ? 1 : -1;
1007
1008  if (ValTy->isPointerType() &&
1009      ValTy->getAs<PointerType>()->isVariableArrayType()) {
1010    // The amount of the addition/subtraction needs to account for the VLA size
1011    CGF.ErrorUnsupported(E, "VLA pointer inc/dec");
1012  }
1013
1014  Value *NextVal;
1015  if (const llvm::PointerType *PT =
1016         dyn_cast<llvm::PointerType>(InVal->getType())) {
1017    llvm::Constant *Inc =
1018      llvm::ConstantInt::get(llvm::Type::getInt32Ty(VMContext), AmountVal);
1019    if (!isa<llvm::FunctionType>(PT->getElementType())) {
1020      QualType PTEE = ValTy->getPointeeType();
1021      if (const ObjCInterfaceType *OIT =
1022          dyn_cast<ObjCInterfaceType>(PTEE)) {
1023        // Handle interface types, which are not represented with a concrete type.
1024        int size = CGF.getContext().getTypeSize(OIT) / 8;
1025        if (!isInc)
1026          size = -size;
1027        Inc = llvm::ConstantInt::get(Inc->getType(), size);
1028        const llvm::Type *i8Ty = llvm::Type::getInt8PtrTy(VMContext);
1029        InVal = Builder.CreateBitCast(InVal, i8Ty);
1030        NextVal = Builder.CreateGEP(InVal, Inc, "add.ptr");
1031        llvm::Value *lhs = LV.getAddress();
1032        lhs = Builder.CreateBitCast(lhs, llvm::PointerType::getUnqual(i8Ty));
1033        LV = LValue::MakeAddr(lhs, CGF.MakeQualifiers(ValTy));
1034      } else
1035        NextVal = Builder.CreateInBoundsGEP(InVal, Inc, "ptrincdec");
1036    } else {
1037      const llvm::Type *i8Ty = llvm::Type::getInt8PtrTy(VMContext);
1038      NextVal = Builder.CreateBitCast(InVal, i8Ty, "tmp");
1039      NextVal = Builder.CreateGEP(NextVal, Inc, "ptrincdec");
1040      NextVal = Builder.CreateBitCast(NextVal, InVal->getType());
1041    }
1042  } else if (InVal->getType() == llvm::Type::getInt1Ty(VMContext) && isInc) {
1043    // Bool++ is an interesting case, due to promotion rules, we get:
1044    // Bool++ -> Bool = Bool+1 -> Bool = (int)Bool+1 ->
1045    // Bool = ((int)Bool+1) != 0
1046    // An interesting aspect of this is that increment is always true.
1047    // Decrement does not have this property.
1048    NextVal = llvm::ConstantInt::getTrue(VMContext);
1049  } else if (isa<llvm::IntegerType>(InVal->getType())) {
1050    NextVal = llvm::ConstantInt::get(InVal->getType(), AmountVal);
1051
1052    // Signed integer overflow is undefined behavior.
1053    if (ValTy->isSignedIntegerType())
1054      NextVal = Builder.CreateNSWAdd(InVal, NextVal, isInc ? "inc" : "dec");
1055    else
1056      NextVal = Builder.CreateAdd(InVal, NextVal, isInc ? "inc" : "dec");
1057  } else {
1058    // Add the inc/dec to the real part.
1059    if (InVal->getType()->isFloatTy())
1060      NextVal =
1061        llvm::ConstantFP::get(VMContext,
1062                              llvm::APFloat(static_cast<float>(AmountVal)));
1063    else if (InVal->getType()->isDoubleTy())
1064      NextVal =
1065        llvm::ConstantFP::get(VMContext,
1066                              llvm::APFloat(static_cast<double>(AmountVal)));
1067    else {
1068      llvm::APFloat F(static_cast<float>(AmountVal));
1069      bool ignored;
1070      F.convert(CGF.Target.getLongDoubleFormat(), llvm::APFloat::rmTowardZero,
1071                &ignored);
1072      NextVal = llvm::ConstantFP::get(VMContext, F);
1073    }
1074    NextVal = Builder.CreateFAdd(InVal, NextVal, isInc ? "inc" : "dec");
1075  }
1076
1077  // Store the updated result through the lvalue.
1078  if (LV.isBitfield())
1079    CGF.EmitStoreThroughBitfieldLValue(RValue::get(NextVal), LV, ValTy,
1080                                       &NextVal);
1081  else
1082    CGF.EmitStoreThroughLValue(RValue::get(NextVal), LV, ValTy);
1083
1084  // If this is a postinc, return the value read from memory, otherwise use the
1085  // updated value.
1086  return isPre ? NextVal : InVal;
1087}
1088
1089
1090Value *ScalarExprEmitter::VisitUnaryMinus(const UnaryOperator *E) {
1091  TestAndClearIgnoreResultAssign();
1092  Value *Op = Visit(E->getSubExpr());
1093  if (Op->getType()->isFPOrFPVector())
1094    return Builder.CreateFNeg(Op, "neg");
1095  return Builder.CreateNeg(Op, "neg");
1096}
1097
1098Value *ScalarExprEmitter::VisitUnaryNot(const UnaryOperator *E) {
1099  TestAndClearIgnoreResultAssign();
1100  Value *Op = Visit(E->getSubExpr());
1101  return Builder.CreateNot(Op, "neg");
1102}
1103
1104Value *ScalarExprEmitter::VisitUnaryLNot(const UnaryOperator *E) {
1105  // Compare operand to zero.
1106  Value *BoolVal = CGF.EvaluateExprAsBool(E->getSubExpr());
1107
1108  // Invert value.
1109  // TODO: Could dynamically modify easy computations here.  For example, if
1110  // the operand is an icmp ne, turn into icmp eq.
1111  BoolVal = Builder.CreateNot(BoolVal, "lnot");
1112
1113  // ZExt result to the expr type.
1114  return Builder.CreateZExt(BoolVal, ConvertType(E->getType()), "lnot.ext");
1115}
1116
1117/// VisitSizeOfAlignOfExpr - Return the size or alignment of the type of
1118/// argument of the sizeof expression as an integer.
1119Value *
1120ScalarExprEmitter::VisitSizeOfAlignOfExpr(const SizeOfAlignOfExpr *E) {
1121  QualType TypeToSize = E->getTypeOfArgument();
1122  if (E->isSizeOf()) {
1123    if (const VariableArrayType *VAT =
1124          CGF.getContext().getAsVariableArrayType(TypeToSize)) {
1125      if (E->isArgumentType()) {
1126        // sizeof(type) - make sure to emit the VLA size.
1127        CGF.EmitVLASize(TypeToSize);
1128      } else {
1129        // C99 6.5.3.4p2: If the argument is an expression of type
1130        // VLA, it is evaluated.
1131        CGF.EmitAnyExpr(E->getArgumentExpr());
1132      }
1133
1134      return CGF.GetVLASize(VAT);
1135    }
1136  }
1137
1138  // If this isn't sizeof(vla), the result must be constant; use the constant
1139  // folding logic so we don't have to duplicate it here.
1140  Expr::EvalResult Result;
1141  E->Evaluate(Result, CGF.getContext());
1142  return llvm::ConstantInt::get(VMContext, Result.Val.getInt());
1143}
1144
1145Value *ScalarExprEmitter::VisitUnaryReal(const UnaryOperator *E) {
1146  Expr *Op = E->getSubExpr();
1147  if (Op->getType()->isAnyComplexType())
1148    return CGF.EmitComplexExpr(Op, false, true, false, true).first;
1149  return Visit(Op);
1150}
1151Value *ScalarExprEmitter::VisitUnaryImag(const UnaryOperator *E) {
1152  Expr *Op = E->getSubExpr();
1153  if (Op->getType()->isAnyComplexType())
1154    return CGF.EmitComplexExpr(Op, true, false, true, false).second;
1155
1156  // __imag on a scalar returns zero.  Emit the subexpr to ensure side
1157  // effects are evaluated, but not the actual value.
1158  if (E->isLvalue(CGF.getContext()) == Expr::LV_Valid)
1159    CGF.EmitLValue(Op);
1160  else
1161    CGF.EmitScalarExpr(Op, true);
1162  return llvm::Constant::getNullValue(ConvertType(E->getType()));
1163}
1164
1165Value *ScalarExprEmitter::VisitUnaryOffsetOf(const UnaryOperator *E) {
1166  Value* ResultAsPtr = EmitLValue(E->getSubExpr()).getAddress();
1167  const llvm::Type* ResultType = ConvertType(E->getType());
1168  return Builder.CreatePtrToInt(ResultAsPtr, ResultType, "offsetof");
1169}
1170
1171//===----------------------------------------------------------------------===//
1172//                           Binary Operators
1173//===----------------------------------------------------------------------===//
1174
1175BinOpInfo ScalarExprEmitter::EmitBinOps(const BinaryOperator *E) {
1176  TestAndClearIgnoreResultAssign();
1177  BinOpInfo Result;
1178  Result.LHS = Visit(E->getLHS());
1179  Result.RHS = Visit(E->getRHS());
1180  Result.Ty  = E->getType();
1181  Result.E = E;
1182  return Result;
1183}
1184
1185Value *ScalarExprEmitter::EmitCompoundAssign(const CompoundAssignOperator *E,
1186                      Value *(ScalarExprEmitter::*Func)(const BinOpInfo &)) {
1187  bool Ignore = TestAndClearIgnoreResultAssign();
1188  QualType LHSTy = E->getLHS()->getType(), RHSTy = E->getRHS()->getType();
1189
1190  BinOpInfo OpInfo;
1191
1192  if (E->getComputationResultType()->isAnyComplexType()) {
1193    // This needs to go through the complex expression emitter, but it's a tad
1194    // complicated to do that... I'm leaving it out for now.  (Note that we do
1195    // actually need the imaginary part of the RHS for multiplication and
1196    // division.)
1197    CGF.ErrorUnsupported(E, "complex compound assignment");
1198    return llvm::UndefValue::get(CGF.ConvertType(E->getType()));
1199  }
1200
1201  // Emit the RHS first.  __block variables need to have the rhs evaluated
1202  // first, plus this should improve codegen a little.
1203  OpInfo.RHS = Visit(E->getRHS());
1204  OpInfo.Ty = E->getComputationResultType();
1205  OpInfo.E = E;
1206  // Load/convert the LHS.
1207  LValue LHSLV = EmitLValue(E->getLHS());
1208  OpInfo.LHS = EmitLoadOfLValue(LHSLV, LHSTy);
1209  OpInfo.LHS = EmitScalarConversion(OpInfo.LHS, LHSTy,
1210                                    E->getComputationLHSType());
1211
1212  // Expand the binary operator.
1213  Value *Result = (this->*Func)(OpInfo);
1214
1215  // Convert the result back to the LHS type.
1216  Result = EmitScalarConversion(Result, E->getComputationResultType(), LHSTy);
1217
1218  // Store the result value into the LHS lvalue. Bit-fields are handled
1219  // specially because the result is altered by the store, i.e., [C99 6.5.16p1]
1220  // 'An assignment expression has the value of the left operand after the
1221  // assignment...'.
1222  if (LHSLV.isBitfield()) {
1223    if (!LHSLV.isVolatileQualified()) {
1224      CGF.EmitStoreThroughBitfieldLValue(RValue::get(Result), LHSLV, LHSTy,
1225                                         &Result);
1226      return Result;
1227    } else
1228      CGF.EmitStoreThroughBitfieldLValue(RValue::get(Result), LHSLV, LHSTy);
1229  } else
1230    CGF.EmitStoreThroughLValue(RValue::get(Result), LHSLV, LHSTy);
1231  if (Ignore)
1232    return 0;
1233  return EmitLoadOfLValue(LHSLV, E->getType());
1234}
1235
1236
1237Value *ScalarExprEmitter::EmitDiv(const BinOpInfo &Ops) {
1238  if (Ops.LHS->getType()->isFPOrFPVector())
1239    return Builder.CreateFDiv(Ops.LHS, Ops.RHS, "div");
1240  else if (Ops.Ty->isUnsignedIntegerType())
1241    return Builder.CreateUDiv(Ops.LHS, Ops.RHS, "div");
1242  else
1243    return Builder.CreateSDiv(Ops.LHS, Ops.RHS, "div");
1244}
1245
1246Value *ScalarExprEmitter::EmitRem(const BinOpInfo &Ops) {
1247  // Rem in C can't be a floating point type: C99 6.5.5p2.
1248  if (Ops.Ty->isUnsignedIntegerType())
1249    return Builder.CreateURem(Ops.LHS, Ops.RHS, "rem");
1250  else
1251    return Builder.CreateSRem(Ops.LHS, Ops.RHS, "rem");
1252}
1253
1254Value *ScalarExprEmitter::EmitOverflowCheckedBinOp(const BinOpInfo &Ops) {
1255  unsigned IID;
1256  unsigned OpID = 0;
1257
1258  switch (Ops.E->getOpcode()) {
1259  case BinaryOperator::Add:
1260  case BinaryOperator::AddAssign:
1261    OpID = 1;
1262    IID = llvm::Intrinsic::sadd_with_overflow;
1263    break;
1264  case BinaryOperator::Sub:
1265  case BinaryOperator::SubAssign:
1266    OpID = 2;
1267    IID = llvm::Intrinsic::ssub_with_overflow;
1268    break;
1269  case BinaryOperator::Mul:
1270  case BinaryOperator::MulAssign:
1271    OpID = 3;
1272    IID = llvm::Intrinsic::smul_with_overflow;
1273    break;
1274  default:
1275    assert(false && "Unsupported operation for overflow detection");
1276    IID = 0;
1277  }
1278  OpID <<= 1;
1279  OpID |= 1;
1280
1281  const llvm::Type *opTy = CGF.CGM.getTypes().ConvertType(Ops.Ty);
1282
1283  llvm::Function *intrinsic = CGF.CGM.getIntrinsic(IID, &opTy, 1);
1284
1285  Value *resultAndOverflow = Builder.CreateCall2(intrinsic, Ops.LHS, Ops.RHS);
1286  Value *result = Builder.CreateExtractValue(resultAndOverflow, 0);
1287  Value *overflow = Builder.CreateExtractValue(resultAndOverflow, 1);
1288
1289  // Branch in case of overflow.
1290  llvm::BasicBlock *initialBB = Builder.GetInsertBlock();
1291  llvm::BasicBlock *overflowBB =
1292    CGF.createBasicBlock("overflow", CGF.CurFn);
1293  llvm::BasicBlock *continueBB =
1294    CGF.createBasicBlock("overflow.continue", CGF.CurFn);
1295
1296  Builder.CreateCondBr(overflow, overflowBB, continueBB);
1297
1298  // Handle overflow
1299
1300  Builder.SetInsertPoint(overflowBB);
1301
1302  // Handler is:
1303  // long long *__overflow_handler)(long long a, long long b, char op,
1304  // char width)
1305  std::vector<const llvm::Type*> handerArgTypes;
1306  handerArgTypes.push_back(llvm::Type::getInt64Ty(VMContext));
1307  handerArgTypes.push_back(llvm::Type::getInt64Ty(VMContext));
1308  handerArgTypes.push_back(llvm::Type::getInt8Ty(VMContext));
1309  handerArgTypes.push_back(llvm::Type::getInt8Ty(VMContext));
1310  llvm::FunctionType *handlerTy = llvm::FunctionType::get(
1311      llvm::Type::getInt64Ty(VMContext), handerArgTypes, false);
1312  llvm::Value *handlerFunction =
1313    CGF.CGM.getModule().getOrInsertGlobal("__overflow_handler",
1314        llvm::PointerType::getUnqual(handlerTy));
1315  handlerFunction = Builder.CreateLoad(handlerFunction);
1316
1317  llvm::Value *handlerResult = Builder.CreateCall4(handlerFunction,
1318      Builder.CreateSExt(Ops.LHS, llvm::Type::getInt64Ty(VMContext)),
1319      Builder.CreateSExt(Ops.RHS, llvm::Type::getInt64Ty(VMContext)),
1320      llvm::ConstantInt::get(llvm::Type::getInt8Ty(VMContext), OpID),
1321      llvm::ConstantInt::get(llvm::Type::getInt8Ty(VMContext),
1322        cast<llvm::IntegerType>(opTy)->getBitWidth()));
1323
1324  handlerResult = Builder.CreateTrunc(handlerResult, opTy);
1325
1326  Builder.CreateBr(continueBB);
1327
1328  // Set up the continuation
1329  Builder.SetInsertPoint(continueBB);
1330  // Get the correct result
1331  llvm::PHINode *phi = Builder.CreatePHI(opTy);
1332  phi->reserveOperandSpace(2);
1333  phi->addIncoming(result, initialBB);
1334  phi->addIncoming(handlerResult, overflowBB);
1335
1336  return phi;
1337}
1338
1339Value *ScalarExprEmitter::EmitAdd(const BinOpInfo &Ops) {
1340  if (!Ops.Ty->isAnyPointerType()) {
1341    if (CGF.getContext().getLangOptions().OverflowChecking &&
1342        Ops.Ty->isSignedIntegerType())
1343      return EmitOverflowCheckedBinOp(Ops);
1344
1345    if (Ops.LHS->getType()->isFPOrFPVector())
1346      return Builder.CreateFAdd(Ops.LHS, Ops.RHS, "add");
1347
1348    // Signed integer overflow is undefined behavior.
1349    if (Ops.Ty->isSignedIntegerType())
1350      return Builder.CreateNSWAdd(Ops.LHS, Ops.RHS, "add");
1351
1352    return Builder.CreateAdd(Ops.LHS, Ops.RHS, "add");
1353  }
1354
1355  if (Ops.Ty->isPointerType() &&
1356      Ops.Ty->getAs<PointerType>()->isVariableArrayType()) {
1357    // The amount of the addition needs to account for the VLA size
1358    CGF.ErrorUnsupported(Ops.E, "VLA pointer addition");
1359  }
1360  Value *Ptr, *Idx;
1361  Expr *IdxExp;
1362  const PointerType *PT = Ops.E->getLHS()->getType()->getAs<PointerType>();
1363  const ObjCObjectPointerType *OPT =
1364    Ops.E->getLHS()->getType()->getAs<ObjCObjectPointerType>();
1365  if (PT || OPT) {
1366    Ptr = Ops.LHS;
1367    Idx = Ops.RHS;
1368    IdxExp = Ops.E->getRHS();
1369  } else {  // int + pointer
1370    PT = Ops.E->getRHS()->getType()->getAs<PointerType>();
1371    OPT = Ops.E->getRHS()->getType()->getAs<ObjCObjectPointerType>();
1372    assert((PT || OPT) && "Invalid add expr");
1373    Ptr = Ops.RHS;
1374    Idx = Ops.LHS;
1375    IdxExp = Ops.E->getLHS();
1376  }
1377
1378  unsigned Width = cast<llvm::IntegerType>(Idx->getType())->getBitWidth();
1379  if (Width < CGF.LLVMPointerWidth) {
1380    // Zero or sign extend the pointer value based on whether the index is
1381    // signed or not.
1382    const llvm::Type *IdxType =
1383        llvm::IntegerType::get(VMContext, CGF.LLVMPointerWidth);
1384    if (IdxExp->getType()->isSignedIntegerType())
1385      Idx = Builder.CreateSExt(Idx, IdxType, "idx.ext");
1386    else
1387      Idx = Builder.CreateZExt(Idx, IdxType, "idx.ext");
1388  }
1389  const QualType ElementType = PT ? PT->getPointeeType() : OPT->getPointeeType();
1390  // Handle interface types, which are not represented with a concrete type.
1391  if (const ObjCInterfaceType *OIT = dyn_cast<ObjCInterfaceType>(ElementType)) {
1392    llvm::Value *InterfaceSize =
1393      llvm::ConstantInt::get(Idx->getType(),
1394                             CGF.getContext().getTypeSize(OIT) / 8);
1395    Idx = Builder.CreateMul(Idx, InterfaceSize);
1396    const llvm::Type *i8Ty = llvm::Type::getInt8PtrTy(VMContext);
1397    Value *Casted = Builder.CreateBitCast(Ptr, i8Ty);
1398    Value *Res = Builder.CreateGEP(Casted, Idx, "add.ptr");
1399    return Builder.CreateBitCast(Res, Ptr->getType());
1400  }
1401
1402  // Explicitly handle GNU void* and function pointer arithmetic extensions. The
1403  // GNU void* casts amount to no-ops since our void* type is i8*, but this is
1404  // future proof.
1405  if (ElementType->isVoidType() || ElementType->isFunctionType()) {
1406    const llvm::Type *i8Ty = llvm::Type::getInt8PtrTy(VMContext);
1407    Value *Casted = Builder.CreateBitCast(Ptr, i8Ty);
1408    Value *Res = Builder.CreateGEP(Casted, Idx, "add.ptr");
1409    return Builder.CreateBitCast(Res, Ptr->getType());
1410  }
1411
1412  return Builder.CreateInBoundsGEP(Ptr, Idx, "add.ptr");
1413}
1414
1415Value *ScalarExprEmitter::EmitSub(const BinOpInfo &Ops) {
1416  if (!isa<llvm::PointerType>(Ops.LHS->getType())) {
1417    if (CGF.getContext().getLangOptions().OverflowChecking
1418        && Ops.Ty->isSignedIntegerType())
1419      return EmitOverflowCheckedBinOp(Ops);
1420
1421    if (Ops.LHS->getType()->isFPOrFPVector())
1422      return Builder.CreateFSub(Ops.LHS, Ops.RHS, "sub");
1423    return Builder.CreateSub(Ops.LHS, Ops.RHS, "sub");
1424  }
1425
1426  if (Ops.E->getLHS()->getType()->isPointerType() &&
1427      Ops.E->getLHS()->getType()->getAs<PointerType>()->isVariableArrayType()) {
1428    // The amount of the addition needs to account for the VLA size for
1429    // ptr-int
1430    // The amount of the division needs to account for the VLA size for
1431    // ptr-ptr.
1432    CGF.ErrorUnsupported(Ops.E, "VLA pointer subtraction");
1433  }
1434
1435  const QualType LHSType = Ops.E->getLHS()->getType();
1436  const QualType LHSElementType = LHSType->getPointeeType();
1437  if (!isa<llvm::PointerType>(Ops.RHS->getType())) {
1438    // pointer - int
1439    Value *Idx = Ops.RHS;
1440    unsigned Width = cast<llvm::IntegerType>(Idx->getType())->getBitWidth();
1441    if (Width < CGF.LLVMPointerWidth) {
1442      // Zero or sign extend the pointer value based on whether the index is
1443      // signed or not.
1444      const llvm::Type *IdxType =
1445          llvm::IntegerType::get(VMContext, CGF.LLVMPointerWidth);
1446      if (Ops.E->getRHS()->getType()->isSignedIntegerType())
1447        Idx = Builder.CreateSExt(Idx, IdxType, "idx.ext");
1448      else
1449        Idx = Builder.CreateZExt(Idx, IdxType, "idx.ext");
1450    }
1451    Idx = Builder.CreateNeg(Idx, "sub.ptr.neg");
1452
1453    // Handle interface types, which are not represented with a concrete type.
1454    if (const ObjCInterfaceType *OIT =
1455        dyn_cast<ObjCInterfaceType>(LHSElementType)) {
1456      llvm::Value *InterfaceSize =
1457        llvm::ConstantInt::get(Idx->getType(),
1458                               CGF.getContext().getTypeSize(OIT) / 8);
1459      Idx = Builder.CreateMul(Idx, InterfaceSize);
1460      const llvm::Type *i8Ty = llvm::Type::getInt8PtrTy(VMContext);
1461      Value *LHSCasted = Builder.CreateBitCast(Ops.LHS, i8Ty);
1462      Value *Res = Builder.CreateGEP(LHSCasted, Idx, "add.ptr");
1463      return Builder.CreateBitCast(Res, Ops.LHS->getType());
1464    }
1465
1466    // Explicitly handle GNU void* and function pointer arithmetic
1467    // extensions. The GNU void* casts amount to no-ops since our void* type is
1468    // i8*, but this is future proof.
1469    if (LHSElementType->isVoidType() || LHSElementType->isFunctionType()) {
1470      const llvm::Type *i8Ty = llvm::Type::getInt8PtrTy(VMContext);
1471      Value *LHSCasted = Builder.CreateBitCast(Ops.LHS, i8Ty);
1472      Value *Res = Builder.CreateGEP(LHSCasted, Idx, "sub.ptr");
1473      return Builder.CreateBitCast(Res, Ops.LHS->getType());
1474    }
1475
1476    return Builder.CreateInBoundsGEP(Ops.LHS, Idx, "sub.ptr");
1477  } else {
1478    // pointer - pointer
1479    Value *LHS = Ops.LHS;
1480    Value *RHS = Ops.RHS;
1481
1482    uint64_t ElementSize;
1483
1484    // Handle GCC extension for pointer arithmetic on void* and function pointer
1485    // types.
1486    if (LHSElementType->isVoidType() || LHSElementType->isFunctionType()) {
1487      ElementSize = 1;
1488    } else {
1489      ElementSize = CGF.getContext().getTypeSize(LHSElementType) / 8;
1490    }
1491
1492    const llvm::Type *ResultType = ConvertType(Ops.Ty);
1493    LHS = Builder.CreatePtrToInt(LHS, ResultType, "sub.ptr.lhs.cast");
1494    RHS = Builder.CreatePtrToInt(RHS, ResultType, "sub.ptr.rhs.cast");
1495    Value *BytesBetween = Builder.CreateSub(LHS, RHS, "sub.ptr.sub");
1496
1497    // Optimize out the shift for element size of 1.
1498    if (ElementSize == 1)
1499      return BytesBetween;
1500
1501    // Otherwise, do a full sdiv. This uses the "exact" form of sdiv, since
1502    // pointer difference in C is only defined in the case where both operands
1503    // are pointing to elements of an array.
1504    Value *BytesPerElt = llvm::ConstantInt::get(ResultType, ElementSize);
1505    return Builder.CreateExactSDiv(BytesBetween, BytesPerElt, "sub.ptr.div");
1506  }
1507}
1508
1509Value *ScalarExprEmitter::EmitShl(const BinOpInfo &Ops) {
1510  // LLVM requires the LHS and RHS to be the same type: promote or truncate the
1511  // RHS to the same size as the LHS.
1512  Value *RHS = Ops.RHS;
1513  if (Ops.LHS->getType() != RHS->getType())
1514    RHS = Builder.CreateIntCast(RHS, Ops.LHS->getType(), false, "sh_prom");
1515
1516  return Builder.CreateShl(Ops.LHS, RHS, "shl");
1517}
1518
1519Value *ScalarExprEmitter::EmitShr(const BinOpInfo &Ops) {
1520  // LLVM requires the LHS and RHS to be the same type: promote or truncate the
1521  // RHS to the same size as the LHS.
1522  Value *RHS = Ops.RHS;
1523  if (Ops.LHS->getType() != RHS->getType())
1524    RHS = Builder.CreateIntCast(RHS, Ops.LHS->getType(), false, "sh_prom");
1525
1526  if (Ops.Ty->isUnsignedIntegerType())
1527    return Builder.CreateLShr(Ops.LHS, RHS, "shr");
1528  return Builder.CreateAShr(Ops.LHS, RHS, "shr");
1529}
1530
1531Value *ScalarExprEmitter::EmitCompare(const BinaryOperator *E,unsigned UICmpOpc,
1532                                      unsigned SICmpOpc, unsigned FCmpOpc) {
1533  TestAndClearIgnoreResultAssign();
1534  Value *Result;
1535  QualType LHSTy = E->getLHS()->getType();
1536  if (!LHSTy->isAnyComplexType()) {
1537    Value *LHS = Visit(E->getLHS());
1538    Value *RHS = Visit(E->getRHS());
1539
1540    if (LHS->getType()->isFPOrFPVector()) {
1541      Result = Builder.CreateFCmp((llvm::CmpInst::Predicate)FCmpOpc,
1542                                  LHS, RHS, "cmp");
1543    } else if (LHSTy->isSignedIntegerType()) {
1544      Result = Builder.CreateICmp((llvm::ICmpInst::Predicate)SICmpOpc,
1545                                  LHS, RHS, "cmp");
1546    } else {
1547      // Unsigned integers and pointers.
1548      Result = Builder.CreateICmp((llvm::ICmpInst::Predicate)UICmpOpc,
1549                                  LHS, RHS, "cmp");
1550    }
1551
1552    // If this is a vector comparison, sign extend the result to the appropriate
1553    // vector integer type and return it (don't convert to bool).
1554    if (LHSTy->isVectorType())
1555      return Builder.CreateSExt(Result, ConvertType(E->getType()), "sext");
1556
1557  } else {
1558    // Complex Comparison: can only be an equality comparison.
1559    CodeGenFunction::ComplexPairTy LHS = CGF.EmitComplexExpr(E->getLHS());
1560    CodeGenFunction::ComplexPairTy RHS = CGF.EmitComplexExpr(E->getRHS());
1561
1562    QualType CETy = LHSTy->getAs<ComplexType>()->getElementType();
1563
1564    Value *ResultR, *ResultI;
1565    if (CETy->isRealFloatingType()) {
1566      ResultR = Builder.CreateFCmp((llvm::FCmpInst::Predicate)FCmpOpc,
1567                                   LHS.first, RHS.first, "cmp.r");
1568      ResultI = Builder.CreateFCmp((llvm::FCmpInst::Predicate)FCmpOpc,
1569                                   LHS.second, RHS.second, "cmp.i");
1570    } else {
1571      // Complex comparisons can only be equality comparisons.  As such, signed
1572      // and unsigned opcodes are the same.
1573      ResultR = Builder.CreateICmp((llvm::ICmpInst::Predicate)UICmpOpc,
1574                                   LHS.first, RHS.first, "cmp.r");
1575      ResultI = Builder.CreateICmp((llvm::ICmpInst::Predicate)UICmpOpc,
1576                                   LHS.second, RHS.second, "cmp.i");
1577    }
1578
1579    if (E->getOpcode() == BinaryOperator::EQ) {
1580      Result = Builder.CreateAnd(ResultR, ResultI, "and.ri");
1581    } else {
1582      assert(E->getOpcode() == BinaryOperator::NE &&
1583             "Complex comparison other than == or != ?");
1584      Result = Builder.CreateOr(ResultR, ResultI, "or.ri");
1585    }
1586  }
1587
1588  return EmitScalarConversion(Result, CGF.getContext().BoolTy, E->getType());
1589}
1590
1591Value *ScalarExprEmitter::VisitBinAssign(const BinaryOperator *E) {
1592  bool Ignore = TestAndClearIgnoreResultAssign();
1593
1594  // __block variables need to have the rhs evaluated first, plus this should
1595  // improve codegen just a little.
1596  Value *RHS = Visit(E->getRHS());
1597  LValue LHS = EmitLValue(E->getLHS());
1598
1599  // Store the value into the LHS.  Bit-fields are handled specially
1600  // because the result is altered by the store, i.e., [C99 6.5.16p1]
1601  // 'An assignment expression has the value of the left operand after
1602  // the assignment...'.
1603  if (LHS.isBitfield()) {
1604    if (!LHS.isVolatileQualified()) {
1605      CGF.EmitStoreThroughBitfieldLValue(RValue::get(RHS), LHS, E->getType(),
1606                                         &RHS);
1607      return RHS;
1608    } else
1609      CGF.EmitStoreThroughBitfieldLValue(RValue::get(RHS), LHS, E->getType());
1610  } else
1611    CGF.EmitStoreThroughLValue(RValue::get(RHS), LHS, E->getType());
1612  if (Ignore)
1613    return 0;
1614  return EmitLoadOfLValue(LHS, E->getType());
1615}
1616
1617Value *ScalarExprEmitter::VisitBinLAnd(const BinaryOperator *E) {
1618  const llvm::Type *ResTy = ConvertType(E->getType());
1619
1620  // If we have 0 && RHS, see if we can elide RHS, if so, just return 0.
1621  // If we have 1 && X, just emit X without inserting the control flow.
1622  if (int Cond = CGF.ConstantFoldsToSimpleInteger(E->getLHS())) {
1623    if (Cond == 1) { // If we have 1 && X, just emit X.
1624      Value *RHSCond = CGF.EvaluateExprAsBool(E->getRHS());
1625      // ZExt result to int or bool.
1626      return Builder.CreateZExtOrBitCast(RHSCond, ResTy, "land.ext");
1627    }
1628
1629    // 0 && RHS: If it is safe, just elide the RHS, and return 0/false.
1630    if (!CGF.ContainsLabel(E->getRHS()))
1631      return llvm::Constant::getNullValue(ResTy);
1632  }
1633
1634  llvm::BasicBlock *ContBlock = CGF.createBasicBlock("land.end");
1635  llvm::BasicBlock *RHSBlock  = CGF.createBasicBlock("land.rhs");
1636
1637  // Branch on the LHS first.  If it is false, go to the failure (cont) block.
1638  CGF.EmitBranchOnBoolExpr(E->getLHS(), RHSBlock, ContBlock);
1639
1640  // Any edges into the ContBlock are now from an (indeterminate number of)
1641  // edges from this first condition.  All of these values will be false.  Start
1642  // setting up the PHI node in the Cont Block for this.
1643  llvm::PHINode *PN = llvm::PHINode::Create(llvm::Type::getInt1Ty(VMContext),
1644                                            "", ContBlock);
1645  PN->reserveOperandSpace(2);  // Normal case, two inputs.
1646  for (llvm::pred_iterator PI = pred_begin(ContBlock), PE = pred_end(ContBlock);
1647       PI != PE; ++PI)
1648    PN->addIncoming(llvm::ConstantInt::getFalse(VMContext), *PI);
1649
1650  CGF.StartConditionalBranch();
1651  CGF.EmitBlock(RHSBlock);
1652  Value *RHSCond = CGF.EvaluateExprAsBool(E->getRHS());
1653  CGF.FinishConditionalBranch();
1654
1655  // Reaquire the RHS block, as there may be subblocks inserted.
1656  RHSBlock = Builder.GetInsertBlock();
1657
1658  // Emit an unconditional branch from this block to ContBlock.  Insert an entry
1659  // into the phi node for the edge with the value of RHSCond.
1660  CGF.EmitBlock(ContBlock);
1661  PN->addIncoming(RHSCond, RHSBlock);
1662
1663  // ZExt result to int.
1664  return Builder.CreateZExtOrBitCast(PN, ResTy, "land.ext");
1665}
1666
1667Value *ScalarExprEmitter::VisitBinLOr(const BinaryOperator *E) {
1668  const llvm::Type *ResTy = ConvertType(E->getType());
1669
1670  // If we have 1 || RHS, see if we can elide RHS, if so, just return 1.
1671  // If we have 0 || X, just emit X without inserting the control flow.
1672  if (int Cond = CGF.ConstantFoldsToSimpleInteger(E->getLHS())) {
1673    if (Cond == -1) { // If we have 0 || X, just emit X.
1674      Value *RHSCond = CGF.EvaluateExprAsBool(E->getRHS());
1675      // ZExt result to int or bool.
1676      return Builder.CreateZExtOrBitCast(RHSCond, ResTy, "lor.ext");
1677    }
1678
1679    // 1 || RHS: If it is safe, just elide the RHS, and return 1/true.
1680    if (!CGF.ContainsLabel(E->getRHS()))
1681      return llvm::ConstantInt::get(ResTy, 1);
1682  }
1683
1684  llvm::BasicBlock *ContBlock = CGF.createBasicBlock("lor.end");
1685  llvm::BasicBlock *RHSBlock = CGF.createBasicBlock("lor.rhs");
1686
1687  // Branch on the LHS first.  If it is true, go to the success (cont) block.
1688  CGF.EmitBranchOnBoolExpr(E->getLHS(), ContBlock, RHSBlock);
1689
1690  // Any edges into the ContBlock are now from an (indeterminate number of)
1691  // edges from this first condition.  All of these values will be true.  Start
1692  // setting up the PHI node in the Cont Block for this.
1693  llvm::PHINode *PN = llvm::PHINode::Create(llvm::Type::getInt1Ty(VMContext),
1694                                            "", ContBlock);
1695  PN->reserveOperandSpace(2);  // Normal case, two inputs.
1696  for (llvm::pred_iterator PI = pred_begin(ContBlock), PE = pred_end(ContBlock);
1697       PI != PE; ++PI)
1698    PN->addIncoming(llvm::ConstantInt::getTrue(VMContext), *PI);
1699
1700  CGF.StartConditionalBranch();
1701
1702  // Emit the RHS condition as a bool value.
1703  CGF.EmitBlock(RHSBlock);
1704  Value *RHSCond = CGF.EvaluateExprAsBool(E->getRHS());
1705
1706  CGF.FinishConditionalBranch();
1707
1708  // Reaquire the RHS block, as there may be subblocks inserted.
1709  RHSBlock = Builder.GetInsertBlock();
1710
1711  // Emit an unconditional branch from this block to ContBlock.  Insert an entry
1712  // into the phi node for the edge with the value of RHSCond.
1713  CGF.EmitBlock(ContBlock);
1714  PN->addIncoming(RHSCond, RHSBlock);
1715
1716  // ZExt result to int.
1717  return Builder.CreateZExtOrBitCast(PN, ResTy, "lor.ext");
1718}
1719
1720Value *ScalarExprEmitter::VisitBinComma(const BinaryOperator *E) {
1721  CGF.EmitStmt(E->getLHS());
1722  CGF.EnsureInsertPoint();
1723  return Visit(E->getRHS());
1724}
1725
1726//===----------------------------------------------------------------------===//
1727//                             Other Operators
1728//===----------------------------------------------------------------------===//
1729
1730/// isCheapEnoughToEvaluateUnconditionally - Return true if the specified
1731/// expression is cheap enough and side-effect-free enough to evaluate
1732/// unconditionally instead of conditionally.  This is used to convert control
1733/// flow into selects in some cases.
1734static bool isCheapEnoughToEvaluateUnconditionally(const Expr *E,
1735                                                   CodeGenFunction &CGF) {
1736  if (const ParenExpr *PE = dyn_cast<ParenExpr>(E))
1737    return isCheapEnoughToEvaluateUnconditionally(PE->getSubExpr(), CGF);
1738
1739  // TODO: Allow anything we can constant fold to an integer or fp constant.
1740  if (isa<IntegerLiteral>(E) || isa<CharacterLiteral>(E) ||
1741      isa<FloatingLiteral>(E))
1742    return true;
1743
1744  // Non-volatile automatic variables too, to get "cond ? X : Y" where
1745  // X and Y are local variables.
1746  if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E))
1747    if (const VarDecl *VD = dyn_cast<VarDecl>(DRE->getDecl()))
1748      if (VD->hasLocalStorage() && !(CGF.getContext()
1749                                     .getCanonicalType(VD->getType())
1750                                     .isVolatileQualified()))
1751        return true;
1752
1753  return false;
1754}
1755
1756
1757Value *ScalarExprEmitter::
1758VisitConditionalOperator(const ConditionalOperator *E) {
1759  TestAndClearIgnoreResultAssign();
1760  // If the condition constant folds and can be elided, try to avoid emitting
1761  // the condition and the dead arm.
1762  if (int Cond = CGF.ConstantFoldsToSimpleInteger(E->getCond())){
1763    Expr *Live = E->getLHS(), *Dead = E->getRHS();
1764    if (Cond == -1)
1765      std::swap(Live, Dead);
1766
1767    // If the dead side doesn't have labels we need, and if the Live side isn't
1768    // the gnu missing ?: extension (which we could handle, but don't bother
1769    // to), just emit the Live part.
1770    if ((!Dead || !CGF.ContainsLabel(Dead)) &&  // No labels in dead part
1771        Live)                                   // Live part isn't missing.
1772      return Visit(Live);
1773  }
1774
1775
1776  // If this is a really simple expression (like x ? 4 : 5), emit this as a
1777  // select instead of as control flow.  We can only do this if it is cheap and
1778  // safe to evaluate the LHS and RHS unconditionally.
1779  if (E->getLHS() && isCheapEnoughToEvaluateUnconditionally(E->getLHS(),
1780                                                            CGF) &&
1781      isCheapEnoughToEvaluateUnconditionally(E->getRHS(), CGF)) {
1782    llvm::Value *CondV = CGF.EvaluateExprAsBool(E->getCond());
1783    llvm::Value *LHS = Visit(E->getLHS());
1784    llvm::Value *RHS = Visit(E->getRHS());
1785    return Builder.CreateSelect(CondV, LHS, RHS, "cond");
1786  }
1787
1788
1789  llvm::BasicBlock *LHSBlock = CGF.createBasicBlock("cond.true");
1790  llvm::BasicBlock *RHSBlock = CGF.createBasicBlock("cond.false");
1791  llvm::BasicBlock *ContBlock = CGF.createBasicBlock("cond.end");
1792  Value *CondVal = 0;
1793
1794  // If we don't have the GNU missing condition extension, emit a branch on bool
1795  // the normal way.
1796  if (E->getLHS()) {
1797    // Otherwise, just use EmitBranchOnBoolExpr to get small and simple code for
1798    // the branch on bool.
1799    CGF.EmitBranchOnBoolExpr(E->getCond(), LHSBlock, RHSBlock);
1800  } else {
1801    // Otherwise, for the ?: extension, evaluate the conditional and then
1802    // convert it to bool the hard way.  We do this explicitly because we need
1803    // the unconverted value for the missing middle value of the ?:.
1804    CondVal = CGF.EmitScalarExpr(E->getCond());
1805
1806    // In some cases, EmitScalarConversion will delete the "CondVal" expression
1807    // if there are no extra uses (an optimization).  Inhibit this by making an
1808    // extra dead use, because we're going to add a use of CondVal later.  We
1809    // don't use the builder for this, because we don't want it to get optimized
1810    // away.  This leaves dead code, but the ?: extension isn't common.
1811    new llvm::BitCastInst(CondVal, CondVal->getType(), "dummy?:holder",
1812                          Builder.GetInsertBlock());
1813
1814    Value *CondBoolVal =
1815      CGF.EmitScalarConversion(CondVal, E->getCond()->getType(),
1816                               CGF.getContext().BoolTy);
1817    Builder.CreateCondBr(CondBoolVal, LHSBlock, RHSBlock);
1818  }
1819
1820  CGF.StartConditionalBranch();
1821  CGF.EmitBlock(LHSBlock);
1822
1823  // Handle the GNU extension for missing LHS.
1824  Value *LHS;
1825  if (E->getLHS())
1826    LHS = Visit(E->getLHS());
1827  else    // Perform promotions, to handle cases like "short ?: int"
1828    LHS = EmitScalarConversion(CondVal, E->getCond()->getType(), E->getType());
1829
1830  CGF.FinishConditionalBranch();
1831  LHSBlock = Builder.GetInsertBlock();
1832  CGF.EmitBranch(ContBlock);
1833
1834  CGF.StartConditionalBranch();
1835  CGF.EmitBlock(RHSBlock);
1836
1837  Value *RHS = Visit(E->getRHS());
1838  CGF.FinishConditionalBranch();
1839  RHSBlock = Builder.GetInsertBlock();
1840  CGF.EmitBranch(ContBlock);
1841
1842  CGF.EmitBlock(ContBlock);
1843
1844  if (!LHS || !RHS) {
1845    assert(E->getType()->isVoidType() && "Non-void value should have a value");
1846    return 0;
1847  }
1848
1849  // Create a PHI node for the real part.
1850  llvm::PHINode *PN = Builder.CreatePHI(LHS->getType(), "cond");
1851  PN->reserveOperandSpace(2);
1852  PN->addIncoming(LHS, LHSBlock);
1853  PN->addIncoming(RHS, RHSBlock);
1854  return PN;
1855}
1856
1857Value *ScalarExprEmitter::VisitChooseExpr(ChooseExpr *E) {
1858  return Visit(E->getChosenSubExpr(CGF.getContext()));
1859}
1860
1861Value *ScalarExprEmitter::VisitVAArgExpr(VAArgExpr *VE) {
1862  llvm::Value *ArgValue = CGF.EmitVAListRef(VE->getSubExpr());
1863  llvm::Value *ArgPtr = CGF.EmitVAArg(ArgValue, VE->getType());
1864
1865  // If EmitVAArg fails, we fall back to the LLVM instruction.
1866  if (!ArgPtr)
1867    return Builder.CreateVAArg(ArgValue, ConvertType(VE->getType()));
1868
1869  // FIXME Volatility.
1870  return Builder.CreateLoad(ArgPtr);
1871}
1872
1873Value *ScalarExprEmitter::VisitBlockExpr(const BlockExpr *BE) {
1874  return CGF.BuildBlockLiteralTmp(BE);
1875}
1876
1877//===----------------------------------------------------------------------===//
1878//                         Entry Point into this File
1879//===----------------------------------------------------------------------===//
1880
1881/// EmitScalarExpr - Emit the computation of the specified expression of scalar
1882/// type, ignoring the result.
1883Value *CodeGenFunction::EmitScalarExpr(const Expr *E, bool IgnoreResultAssign) {
1884  assert(E && !hasAggregateLLVMType(E->getType()) &&
1885         "Invalid scalar expression to emit");
1886
1887  return ScalarExprEmitter(*this, IgnoreResultAssign)
1888    .Visit(const_cast<Expr*>(E));
1889}
1890
1891/// EmitScalarConversion - Emit a conversion from the specified type to the
1892/// specified destination type, both of which are LLVM scalar types.
1893Value *CodeGenFunction::EmitScalarConversion(Value *Src, QualType SrcTy,
1894                                             QualType DstTy) {
1895  assert(!hasAggregateLLVMType(SrcTy) && !hasAggregateLLVMType(DstTy) &&
1896         "Invalid scalar expression to emit");
1897  return ScalarExprEmitter(*this).EmitScalarConversion(Src, SrcTy, DstTy);
1898}
1899
1900/// EmitComplexToScalarConversion - Emit a conversion from the specified complex
1901/// type to the specified destination type, where the destination type is an
1902/// LLVM scalar type.
1903Value *CodeGenFunction::EmitComplexToScalarConversion(ComplexPairTy Src,
1904                                                      QualType SrcTy,
1905                                                      QualType DstTy) {
1906  assert(SrcTy->isAnyComplexType() && !hasAggregateLLVMType(DstTy) &&
1907         "Invalid complex -> scalar conversion");
1908  return ScalarExprEmitter(*this).EmitComplexToScalarConversion(Src, SrcTy,
1909                                                                DstTy);
1910}
1911
1912Value *CodeGenFunction::EmitShuffleVector(Value* V1, Value *V2, ...) {
1913  assert(V1->getType() == V2->getType() &&
1914         "Vector operands must be of the same type");
1915  unsigned NumElements =
1916    cast<llvm::VectorType>(V1->getType())->getNumElements();
1917
1918  va_list va;
1919  va_start(va, V2);
1920
1921  llvm::SmallVector<llvm::Constant*, 16> Args;
1922  for (unsigned i = 0; i < NumElements; i++) {
1923    int n = va_arg(va, int);
1924    assert(n >= 0 && n < (int)NumElements * 2 &&
1925           "Vector shuffle index out of bounds!");
1926    Args.push_back(llvm::ConstantInt::get(
1927                                         llvm::Type::getInt32Ty(VMContext), n));
1928  }
1929
1930  const char *Name = va_arg(va, const char *);
1931  va_end(va);
1932
1933  llvm::Constant *Mask = llvm::ConstantVector::get(&Args[0], NumElements);
1934
1935  return Builder.CreateShuffleVector(V1, V2, Mask, Name);
1936}
1937
1938llvm::Value *CodeGenFunction::EmitVector(llvm::Value * const *Vals,
1939                                         unsigned NumVals, bool isSplat) {
1940  llvm::Value *Vec
1941    = llvm::UndefValue::get(llvm::VectorType::get(Vals[0]->getType(), NumVals));
1942
1943  for (unsigned i = 0, e = NumVals; i != e; ++i) {
1944    llvm::Value *Val = isSplat ? Vals[0] : Vals[i];
1945    llvm::Value *Idx = llvm::ConstantInt::get(
1946                                          llvm::Type::getInt32Ty(VMContext), i);
1947    Vec = Builder.CreateInsertElement(Vec, Val, Idx, "tmp");
1948  }
1949
1950  return Vec;
1951}
1952