Expr.cpp revision 7f4f86a2167abc116275e49c81350fc3225485e5 
1//===--- Expr.cpp - Expression AST Node Implementation --------------------===//
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 file implements the Expr class and subclasses.
11//
12//===----------------------------------------------------------------------===//
13
14#include "clang/AST/Expr.h"
15#include "clang/AST/ExprCXX.h"
16#include "clang/AST/APValue.h"
17#include "clang/AST/ASTContext.h"
18#include "clang/AST/DeclObjC.h"
19#include "clang/AST/DeclCXX.h"
20#include "clang/AST/DeclTemplate.h"
21#include "clang/AST/RecordLayout.h"
22#include "clang/AST/StmtVisitor.h"
23#include "clang/Basic/Builtins.h"
24#include "clang/Basic/TargetInfo.h"
25#include "llvm/Support/raw_ostream.h"
26#include <algorithm>
27using namespace clang;
28
29//===----------------------------------------------------------------------===//
30// Primary Expressions.
31//===----------------------------------------------------------------------===//
32
33// FIXME: Maybe this should use DeclPrinter with a special "print predefined
34// expr" policy instead.
35std::string PredefinedExpr::ComputeName(ASTContext &Context, IdentType IT,
36                                        const Decl *CurrentDecl) {
37  if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(CurrentDecl)) {
38    if (IT != PrettyFunction)
39      return FD->getNameAsString();
40
41    llvm::SmallString<256> Name;
42    llvm::raw_svector_ostream Out(Name);
43
44    if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(FD)) {
45      if (MD->isVirtual())
46        Out << "virtual ";
47    }
48
49    PrintingPolicy Policy(Context.getLangOptions());
50    Policy.SuppressTagKind = true;
51
52    std::string Proto = FD->getQualifiedNameAsString(Policy);
53
54    const FunctionType *AFT = FD->getType()->getAsFunctionType();
55    const FunctionProtoType *FT = 0;
56    if (FD->hasWrittenPrototype())
57      FT = dyn_cast<FunctionProtoType>(AFT);
58
59    Proto += "(";
60    if (FT) {
61      llvm::raw_string_ostream POut(Proto);
62      for (unsigned i = 0, e = FD->getNumParams(); i != e; ++i) {
63        if (i) POut << ", ";
64        std::string Param;
65        FD->getParamDecl(i)->getType().getAsStringInternal(Param, Policy);
66        POut << Param;
67      }
68
69      if (FT->isVariadic()) {
70        if (FD->getNumParams()) POut << ", ";
71        POut << "...";
72      }
73    }
74    Proto += ")";
75
76    AFT->getResultType().getAsStringInternal(Proto, Policy);
77
78    Out << Proto;
79
80    Out.flush();
81    return Name.str().str();
82  }
83  if (const ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(CurrentDecl)) {
84    llvm::SmallString<256> Name;
85    llvm::raw_svector_ostream Out(Name);
86    Out << (MD->isInstanceMethod() ? '-' : '+');
87    Out << '[';
88    Out << MD->getClassInterface()->getNameAsString();
89    if (const ObjCCategoryImplDecl *CID =
90        dyn_cast<ObjCCategoryImplDecl>(MD->getDeclContext())) {
91      Out << '(';
92      Out <<  CID->getNameAsString();
93      Out <<  ')';
94    }
95    Out <<  ' ';
96    Out << MD->getSelector().getAsString();
97    Out <<  ']';
98
99    Out.flush();
100    return Name.str().str();
101  }
102  if (isa<TranslationUnitDecl>(CurrentDecl) && IT == PrettyFunction) {
103    // __PRETTY_FUNCTION__ -> "top level", the others produce an empty string.
104    return "top level";
105  }
106  return "";
107}
108
109/// getValueAsApproximateDouble - This returns the value as an inaccurate
110/// double.  Note that this may cause loss of precision, but is useful for
111/// debugging dumps, etc.
112double FloatingLiteral::getValueAsApproximateDouble() const {
113  llvm::APFloat V = getValue();
114  bool ignored;
115  V.convert(llvm::APFloat::IEEEdouble, llvm::APFloat::rmNearestTiesToEven,
116            &ignored);
117  return V.convertToDouble();
118}
119
120StringLiteral *StringLiteral::Create(ASTContext &C, const char *StrData,
121                                     unsigned ByteLength, bool Wide,
122                                     QualType Ty,
123                                     const SourceLocation *Loc,
124                                     unsigned NumStrs) {
125  // Allocate enough space for the StringLiteral plus an array of locations for
126  // any concatenated string tokens.
127  void *Mem = C.Allocate(sizeof(StringLiteral)+
128                         sizeof(SourceLocation)*(NumStrs-1),
129                         llvm::alignof<StringLiteral>());
130  StringLiteral *SL = new (Mem) StringLiteral(Ty);
131
132  // OPTIMIZE: could allocate this appended to the StringLiteral.
133  char *AStrData = new (C, 1) char[ByteLength];
134  memcpy(AStrData, StrData, ByteLength);
135  SL->StrData = AStrData;
136  SL->ByteLength = ByteLength;
137  SL->IsWide = Wide;
138  SL->TokLocs[0] = Loc[0];
139  SL->NumConcatenated = NumStrs;
140
141  if (NumStrs != 1)
142    memcpy(&SL->TokLocs[1], Loc+1, sizeof(SourceLocation)*(NumStrs-1));
143  return SL;
144}
145
146StringLiteral *StringLiteral::CreateEmpty(ASTContext &C, unsigned NumStrs) {
147  void *Mem = C.Allocate(sizeof(StringLiteral)+
148                         sizeof(SourceLocation)*(NumStrs-1),
149                         llvm::alignof<StringLiteral>());
150  StringLiteral *SL = new (Mem) StringLiteral(QualType());
151  SL->StrData = 0;
152  SL->ByteLength = 0;
153  SL->NumConcatenated = NumStrs;
154  return SL;
155}
156
157void StringLiteral::DoDestroy(ASTContext &C) {
158  C.Deallocate(const_cast<char*>(StrData));
159  Expr::DoDestroy(C);
160}
161
162void StringLiteral::setStrData(ASTContext &C, const char *Str, unsigned Len) {
163  if (StrData)
164    C.Deallocate(const_cast<char*>(StrData));
165
166  char *AStrData = new (C, 1) char[Len];
167  memcpy(AStrData, Str, Len);
168  StrData = AStrData;
169  ByteLength = Len;
170}
171
172/// getOpcodeStr - Turn an Opcode enum value into the punctuation char it
173/// corresponds to, e.g. "sizeof" or "[pre]++".
174const char *UnaryOperator::getOpcodeStr(Opcode Op) {
175  switch (Op) {
176  default: assert(0 && "Unknown unary operator");
177  case PostInc: return "++";
178  case PostDec: return "--";
179  case PreInc:  return "++";
180  case PreDec:  return "--";
181  case AddrOf:  return "&";
182  case Deref:   return "*";
183  case Plus:    return "+";
184  case Minus:   return "-";
185  case Not:     return "~";
186  case LNot:    return "!";
187  case Real:    return "__real";
188  case Imag:    return "__imag";
189  case Extension: return "__extension__";
190  case OffsetOf: return "__builtin_offsetof";
191  }
192}
193
194UnaryOperator::Opcode
195UnaryOperator::getOverloadedOpcode(OverloadedOperatorKind OO, bool Postfix) {
196  switch (OO) {
197  default: assert(false && "No unary operator for overloaded function");
198  case OO_PlusPlus:   return Postfix ? PostInc : PreInc;
199  case OO_MinusMinus: return Postfix ? PostDec : PreDec;
200  case OO_Amp:        return AddrOf;
201  case OO_Star:       return Deref;
202  case OO_Plus:       return Plus;
203  case OO_Minus:      return Minus;
204  case OO_Tilde:      return Not;
205  case OO_Exclaim:    return LNot;
206  }
207}
208
209OverloadedOperatorKind UnaryOperator::getOverloadedOperator(Opcode Opc) {
210  switch (Opc) {
211  case PostInc: case PreInc: return OO_PlusPlus;
212  case PostDec: case PreDec: return OO_MinusMinus;
213  case AddrOf: return OO_Amp;
214  case Deref: return OO_Star;
215  case Plus: return OO_Plus;
216  case Minus: return OO_Minus;
217  case Not: return OO_Tilde;
218  case LNot: return OO_Exclaim;
219  default: return OO_None;
220  }
221}
222
223
224//===----------------------------------------------------------------------===//
225// Postfix Operators.
226//===----------------------------------------------------------------------===//
227
228CallExpr::CallExpr(ASTContext& C, StmtClass SC, Expr *fn, Expr **args,
229                   unsigned numargs, QualType t, SourceLocation rparenloc)
230  : Expr(SC, t,
231         fn->isTypeDependent() || hasAnyTypeDependentArguments(args, numargs),
232         fn->isValueDependent() || hasAnyValueDependentArguments(args,numargs)),
233    NumArgs(numargs) {
234
235  SubExprs = new (C) Stmt*[numargs+1];
236  SubExprs[FN] = fn;
237  for (unsigned i = 0; i != numargs; ++i)
238    SubExprs[i+ARGS_START] = args[i];
239
240  RParenLoc = rparenloc;
241}
242
243CallExpr::CallExpr(ASTContext& C, Expr *fn, Expr **args, unsigned numargs,
244                   QualType t, SourceLocation rparenloc)
245  : Expr(CallExprClass, t,
246         fn->isTypeDependent() || hasAnyTypeDependentArguments(args, numargs),
247         fn->isValueDependent() || hasAnyValueDependentArguments(args,numargs)),
248    NumArgs(numargs) {
249
250  SubExprs = new (C) Stmt*[numargs+1];
251  SubExprs[FN] = fn;
252  for (unsigned i = 0; i != numargs; ++i)
253    SubExprs[i+ARGS_START] = args[i];
254
255  RParenLoc = rparenloc;
256}
257
258CallExpr::CallExpr(ASTContext &C, StmtClass SC, EmptyShell Empty)
259  : Expr(SC, Empty), SubExprs(0), NumArgs(0) {
260  SubExprs = new (C) Stmt*[1];
261}
262
263void CallExpr::DoDestroy(ASTContext& C) {
264  DestroyChildren(C);
265  if (SubExprs) C.Deallocate(SubExprs);
266  this->~CallExpr();
267  C.Deallocate(this);
268}
269
270FunctionDecl *CallExpr::getDirectCallee() {
271  Expr *CEE = getCallee()->IgnoreParenCasts();
272  if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(CEE))
273    return dyn_cast<FunctionDecl>(DRE->getDecl());
274
275  return 0;
276}
277
278/// setNumArgs - This changes the number of arguments present in this call.
279/// Any orphaned expressions are deleted by this, and any new operands are set
280/// to null.
281void CallExpr::setNumArgs(ASTContext& C, unsigned NumArgs) {
282  // No change, just return.
283  if (NumArgs == getNumArgs()) return;
284
285  // If shrinking # arguments, just delete the extras and forgot them.
286  if (NumArgs < getNumArgs()) {
287    for (unsigned i = NumArgs, e = getNumArgs(); i != e; ++i)
288      getArg(i)->Destroy(C);
289    this->NumArgs = NumArgs;
290    return;
291  }
292
293  // Otherwise, we are growing the # arguments.  New an bigger argument array.
294  Stmt **NewSubExprs = new (C) Stmt*[NumArgs+1];
295  // Copy over args.
296  for (unsigned i = 0; i != getNumArgs()+ARGS_START; ++i)
297    NewSubExprs[i] = SubExprs[i];
298  // Null out new args.
299  for (unsigned i = getNumArgs()+ARGS_START; i != NumArgs+ARGS_START; ++i)
300    NewSubExprs[i] = 0;
301
302  if (SubExprs) C.Deallocate(SubExprs);
303  SubExprs = NewSubExprs;
304  this->NumArgs = NumArgs;
305}
306
307/// isBuiltinCall - If this is a call to a builtin, return the builtin ID.  If
308/// not, return 0.
309unsigned CallExpr::isBuiltinCall(ASTContext &Context) const {
310  // All simple function calls (e.g. func()) are implicitly cast to pointer to
311  // function. As a result, we try and obtain the DeclRefExpr from the
312  // ImplicitCastExpr.
313  const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(getCallee());
314  if (!ICE) // FIXME: deal with more complex calls (e.g. (func)(), (*func)()).
315    return 0;
316
317  const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(ICE->getSubExpr());
318  if (!DRE)
319    return 0;
320
321  const FunctionDecl *FDecl = dyn_cast<FunctionDecl>(DRE->getDecl());
322  if (!FDecl)
323    return 0;
324
325  if (!FDecl->getIdentifier())
326    return 0;
327
328  return FDecl->getBuiltinID(Context);
329}
330
331QualType CallExpr::getCallReturnType() const {
332  QualType CalleeType = getCallee()->getType();
333  if (const PointerType *FnTypePtr = CalleeType->getAs<PointerType>())
334    CalleeType = FnTypePtr->getPointeeType();
335  else if (const BlockPointerType *BPT = CalleeType->getAs<BlockPointerType>())
336    CalleeType = BPT->getPointeeType();
337
338  const FunctionType *FnType = CalleeType->getAsFunctionType();
339  return FnType->getResultType();
340}
341
342MemberExpr::MemberExpr(Expr *base, bool isarrow, NestedNameSpecifier *qual,
343                       SourceRange qualrange, NamedDecl *memberdecl,
344                       SourceLocation l, bool has_explicit,
345                       SourceLocation langle,
346                       const TemplateArgument *targs, unsigned numtargs,
347                       SourceLocation rangle, QualType ty)
348  : Expr(MemberExprClass, ty,
349         base->isTypeDependent() || (qual && qual->isDependent()),
350         base->isValueDependent() || (qual && qual->isDependent())),
351    Base(base), MemberDecl(memberdecl), MemberLoc(l), IsArrow(isarrow),
352    HasQualifier(qual != 0), HasExplicitTemplateArgumentList(has_explicit) {
353  // Initialize the qualifier, if any.
354  if (HasQualifier) {
355    NameQualifier *NQ = getMemberQualifier();
356    NQ->NNS = qual;
357    NQ->Range = qualrange;
358  }
359
360  // Initialize the explicit template argument list, if any.
361  if (HasExplicitTemplateArgumentList) {
362    ExplicitTemplateArgumentList *ETemplateArgs
363      = getExplicitTemplateArgumentList();
364    ETemplateArgs->LAngleLoc = langle;
365    ETemplateArgs->RAngleLoc = rangle;
366    ETemplateArgs->NumTemplateArgs = numtargs;
367
368    TemplateArgument *TemplateArgs = ETemplateArgs->getTemplateArgs();
369    for (unsigned I = 0; I < numtargs; ++I)
370      new (TemplateArgs + I) TemplateArgument(targs[I]);
371  }
372}
373
374MemberExpr *MemberExpr::Create(ASTContext &C, Expr *base, bool isarrow,
375                               NestedNameSpecifier *qual,
376                               SourceRange qualrange,
377                               NamedDecl *memberdecl,
378                               SourceLocation l,
379                               bool has_explicit,
380                               SourceLocation langle,
381                               const TemplateArgument *targs,
382                               unsigned numtargs,
383                               SourceLocation rangle,
384                               QualType ty) {
385  std::size_t Size = sizeof(MemberExpr);
386  if (qual != 0)
387    Size += sizeof(NameQualifier);
388
389  if (has_explicit)
390    Size += sizeof(ExplicitTemplateArgumentList) +
391    sizeof(TemplateArgument) * numtargs;
392
393  void *Mem = C.Allocate(Size, llvm::alignof<MemberExpr>());
394  return new (Mem) MemberExpr(base, isarrow, qual, qualrange, memberdecl, l,
395                              has_explicit, langle, targs, numtargs, rangle,
396                              ty);
397}
398
399const char *CastExpr::getCastKindName() const {
400  switch (getCastKind()) {
401  case CastExpr::CK_Unknown:
402    return "Unknown";
403  case CastExpr::CK_BitCast:
404    return "BitCast";
405  case CastExpr::CK_NoOp:
406    return "NoOp";
407  case CastExpr::CK_DerivedToBase:
408    return "DerivedToBase";
409  case CastExpr::CK_Dynamic:
410    return "Dynamic";
411  case CastExpr::CK_ToUnion:
412    return "ToUnion";
413  case CastExpr::CK_ArrayToPointerDecay:
414    return "ArrayToPointerDecay";
415  case CastExpr::CK_FunctionToPointerDecay:
416    return "FunctionToPointerDecay";
417  case CastExpr::CK_NullToMemberPointer:
418    return "NullToMemberPointer";
419  case CastExpr::CK_BaseToDerivedMemberPointer:
420    return "BaseToDerivedMemberPointer";
421  case CastExpr::CK_UserDefinedConversion:
422    return "UserDefinedConversion";
423  case CastExpr::CK_ConstructorConversion:
424    return "ConstructorConversion";
425  }
426
427  assert(0 && "Unhandled cast kind!");
428  return 0;
429}
430
431/// getOpcodeStr - Turn an Opcode enum value into the punctuation char it
432/// corresponds to, e.g. "<<=".
433const char *BinaryOperator::getOpcodeStr(Opcode Op) {
434  switch (Op) {
435  case PtrMemD:   return ".*";
436  case PtrMemI:   return "->*";
437  case Mul:       return "*";
438  case Div:       return "/";
439  case Rem:       return "%";
440  case Add:       return "+";
441  case Sub:       return "-";
442  case Shl:       return "<<";
443  case Shr:       return ">>";
444  case LT:        return "<";
445  case GT:        return ">";
446  case LE:        return "<=";
447  case GE:        return ">=";
448  case EQ:        return "==";
449  case NE:        return "!=";
450  case And:       return "&";
451  case Xor:       return "^";
452  case Or:        return "|";
453  case LAnd:      return "&&";
454  case LOr:       return "||";
455  case Assign:    return "=";
456  case MulAssign: return "*=";
457  case DivAssign: return "/=";
458  case RemAssign: return "%=";
459  case AddAssign: return "+=";
460  case SubAssign: return "-=";
461  case ShlAssign: return "<<=";
462  case ShrAssign: return ">>=";
463  case AndAssign: return "&=";
464  case XorAssign: return "^=";
465  case OrAssign:  return "|=";
466  case Comma:     return ",";
467  }
468
469  return "";
470}
471
472BinaryOperator::Opcode
473BinaryOperator::getOverloadedOpcode(OverloadedOperatorKind OO) {
474  switch (OO) {
475  default: assert(false && "Not an overloadable binary operator");
476  case OO_Plus: return Add;
477  case OO_Minus: return Sub;
478  case OO_Star: return Mul;
479  case OO_Slash: return Div;
480  case OO_Percent: return Rem;
481  case OO_Caret: return Xor;
482  case OO_Amp: return And;
483  case OO_Pipe: return Or;
484  case OO_Equal: return Assign;
485  case OO_Less: return LT;
486  case OO_Greater: return GT;
487  case OO_PlusEqual: return AddAssign;
488  case OO_MinusEqual: return SubAssign;
489  case OO_StarEqual: return MulAssign;
490  case OO_SlashEqual: return DivAssign;
491  case OO_PercentEqual: return RemAssign;
492  case OO_CaretEqual: return XorAssign;
493  case OO_AmpEqual: return AndAssign;
494  case OO_PipeEqual: return OrAssign;
495  case OO_LessLess: return Shl;
496  case OO_GreaterGreater: return Shr;
497  case OO_LessLessEqual: return ShlAssign;
498  case OO_GreaterGreaterEqual: return ShrAssign;
499  case OO_EqualEqual: return EQ;
500  case OO_ExclaimEqual: return NE;
501  case OO_LessEqual: return LE;
502  case OO_GreaterEqual: return GE;
503  case OO_AmpAmp: return LAnd;
504  case OO_PipePipe: return LOr;
505  case OO_Comma: return Comma;
506  case OO_ArrowStar: return PtrMemI;
507  }
508}
509
510OverloadedOperatorKind BinaryOperator::getOverloadedOperator(Opcode Opc) {
511  static const OverloadedOperatorKind OverOps[] = {
512    /* .* Cannot be overloaded */OO_None, OO_ArrowStar,
513    OO_Star, OO_Slash, OO_Percent,
514    OO_Plus, OO_Minus,
515    OO_LessLess, OO_GreaterGreater,
516    OO_Less, OO_Greater, OO_LessEqual, OO_GreaterEqual,
517    OO_EqualEqual, OO_ExclaimEqual,
518    OO_Amp,
519    OO_Caret,
520    OO_Pipe,
521    OO_AmpAmp,
522    OO_PipePipe,
523    OO_Equal, OO_StarEqual,
524    OO_SlashEqual, OO_PercentEqual,
525    OO_PlusEqual, OO_MinusEqual,
526    OO_LessLessEqual, OO_GreaterGreaterEqual,
527    OO_AmpEqual, OO_CaretEqual,
528    OO_PipeEqual,
529    OO_Comma
530  };
531  return OverOps[Opc];
532}
533
534InitListExpr::InitListExpr(SourceLocation lbraceloc,
535                           Expr **initExprs, unsigned numInits,
536                           SourceLocation rbraceloc)
537  : Expr(InitListExprClass, QualType(),
538         hasAnyTypeDependentArguments(initExprs, numInits),
539         hasAnyValueDependentArguments(initExprs, numInits)),
540    LBraceLoc(lbraceloc), RBraceLoc(rbraceloc), SyntacticForm(0),
541    UnionFieldInit(0), HadArrayRangeDesignator(false) {
542
543  InitExprs.insert(InitExprs.end(), initExprs, initExprs+numInits);
544}
545
546void InitListExpr::reserveInits(unsigned NumInits) {
547  if (NumInits > InitExprs.size())
548    InitExprs.reserve(NumInits);
549}
550
551void InitListExpr::resizeInits(ASTContext &Context, unsigned NumInits) {
552  for (unsigned Idx = NumInits, LastIdx = InitExprs.size();
553       Idx < LastIdx; ++Idx)
554    InitExprs[Idx]->Destroy(Context);
555  InitExprs.resize(NumInits, 0);
556}
557
558Expr *InitListExpr::updateInit(unsigned Init, Expr *expr) {
559  if (Init >= InitExprs.size()) {
560    InitExprs.insert(InitExprs.end(), Init - InitExprs.size() + 1, 0);
561    InitExprs.back() = expr;
562    return 0;
563  }
564
565  Expr *Result = cast_or_null<Expr>(InitExprs[Init]);
566  InitExprs[Init] = expr;
567  return Result;
568}
569
570/// getFunctionType - Return the underlying function type for this block.
571///
572const FunctionType *BlockExpr::getFunctionType() const {
573  return getType()->getAs<BlockPointerType>()->
574                    getPointeeType()->getAsFunctionType();
575}
576
577SourceLocation BlockExpr::getCaretLocation() const {
578  return TheBlock->getCaretLocation();
579}
580const Stmt *BlockExpr::getBody() const {
581  return TheBlock->getBody();
582}
583Stmt *BlockExpr::getBody() {
584  return TheBlock->getBody();
585}
586
587
588//===----------------------------------------------------------------------===//
589// Generic Expression Routines
590//===----------------------------------------------------------------------===//
591
592/// isUnusedResultAWarning - Return true if this immediate expression should
593/// be warned about if the result is unused.  If so, fill in Loc and Ranges
594/// with location to warn on and the source range[s] to report with the
595/// warning.
596bool Expr::isUnusedResultAWarning(SourceLocation &Loc, SourceRange &R1,
597                                  SourceRange &R2) const {
598  // Don't warn if the expr is type dependent. The type could end up
599  // instantiating to void.
600  if (isTypeDependent())
601    return false;
602
603  switch (getStmtClass()) {
604  default:
605    Loc = getExprLoc();
606    R1 = getSourceRange();
607    return true;
608  case ParenExprClass:
609    return cast<ParenExpr>(this)->getSubExpr()->
610      isUnusedResultAWarning(Loc, R1, R2);
611  case UnaryOperatorClass: {
612    const UnaryOperator *UO = cast<UnaryOperator>(this);
613
614    switch (UO->getOpcode()) {
615    default: break;
616    case UnaryOperator::PostInc:
617    case UnaryOperator::PostDec:
618    case UnaryOperator::PreInc:
619    case UnaryOperator::PreDec:                 // ++/--
620      return false;  // Not a warning.
621    case UnaryOperator::Deref:
622      // Dereferencing a volatile pointer is a side-effect.
623      if (getType().isVolatileQualified())
624        return false;
625      break;
626    case UnaryOperator::Real:
627    case UnaryOperator::Imag:
628      // accessing a piece of a volatile complex is a side-effect.
629      if (UO->getSubExpr()->getType().isVolatileQualified())
630        return false;
631      break;
632    case UnaryOperator::Extension:
633      return UO->getSubExpr()->isUnusedResultAWarning(Loc, R1, R2);
634    }
635    Loc = UO->getOperatorLoc();
636    R1 = UO->getSubExpr()->getSourceRange();
637    return true;
638  }
639  case BinaryOperatorClass: {
640    const BinaryOperator *BO = cast<BinaryOperator>(this);
641    // Consider comma to have side effects if the LHS or RHS does.
642    if (BO->getOpcode() == BinaryOperator::Comma)
643      return BO->getRHS()->isUnusedResultAWarning(Loc, R1, R2) ||
644             BO->getLHS()->isUnusedResultAWarning(Loc, R1, R2);
645
646    if (BO->isAssignmentOp())
647      return false;
648    Loc = BO->getOperatorLoc();
649    R1 = BO->getLHS()->getSourceRange();
650    R2 = BO->getRHS()->getSourceRange();
651    return true;
652  }
653  case CompoundAssignOperatorClass:
654    return false;
655
656  case ConditionalOperatorClass: {
657    // The condition must be evaluated, but if either the LHS or RHS is a
658    // warning, warn about them.
659    const ConditionalOperator *Exp = cast<ConditionalOperator>(this);
660    if (Exp->getLHS() &&
661        Exp->getLHS()->isUnusedResultAWarning(Loc, R1, R2))
662      return true;
663    return Exp->getRHS()->isUnusedResultAWarning(Loc, R1, R2);
664  }
665
666  case MemberExprClass:
667    // If the base pointer or element is to a volatile pointer/field, accessing
668    // it is a side effect.
669    if (getType().isVolatileQualified())
670      return false;
671    Loc = cast<MemberExpr>(this)->getMemberLoc();
672    R1 = SourceRange(Loc, Loc);
673    R2 = cast<MemberExpr>(this)->getBase()->getSourceRange();
674    return true;
675
676  case ArraySubscriptExprClass:
677    // If the base pointer or element is to a volatile pointer/field, accessing
678    // it is a side effect.
679    if (getType().isVolatileQualified())
680      return false;
681    Loc = cast<ArraySubscriptExpr>(this)->getRBracketLoc();
682    R1 = cast<ArraySubscriptExpr>(this)->getLHS()->getSourceRange();
683    R2 = cast<ArraySubscriptExpr>(this)->getRHS()->getSourceRange();
684    return true;
685
686  case CallExprClass:
687  case CXXOperatorCallExprClass:
688  case CXXMemberCallExprClass: {
689    // If this is a direct call, get the callee.
690    const CallExpr *CE = cast<CallExpr>(this);
691    const Expr *CalleeExpr = CE->getCallee()->IgnoreParenCasts();
692    if (const DeclRefExpr *CalleeDRE = dyn_cast<DeclRefExpr>(CalleeExpr)) {
693      // If the callee has attribute pure, const, or warn_unused_result, warn
694      // about it. void foo() { strlen("bar"); } should warn.
695      if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(CalleeDRE->getDecl()))
696        if (FD->getAttr<WarnUnusedResultAttr>() ||
697            FD->getAttr<PureAttr>() || FD->getAttr<ConstAttr>()) {
698          Loc = CE->getCallee()->getLocStart();
699          R1 = CE->getCallee()->getSourceRange();
700
701          if (unsigned NumArgs = CE->getNumArgs())
702            R2 = SourceRange(CE->getArg(0)->getLocStart(),
703                             CE->getArg(NumArgs-1)->getLocEnd());
704          return true;
705        }
706    }
707    return false;
708  }
709  case ObjCMessageExprClass:
710    return false;
711
712  case ObjCImplicitSetterGetterRefExprClass: {   // Dot syntax for message send.
713#if 0
714    const ObjCImplicitSetterGetterRefExpr *Ref =
715      cast<ObjCImplicitSetterGetterRefExpr>(this);
716    // FIXME: We really want the location of the '.' here.
717    Loc = Ref->getLocation();
718    R1 = SourceRange(Ref->getLocation(), Ref->getLocation());
719    if (Ref->getBase())
720      R2 = Ref->getBase()->getSourceRange();
721#else
722    Loc = getExprLoc();
723    R1 = getSourceRange();
724#endif
725    return true;
726  }
727  case StmtExprClass: {
728    // Statement exprs don't logically have side effects themselves, but are
729    // sometimes used in macros in ways that give them a type that is unused.
730    // For example ({ blah; foo(); }) will end up with a type if foo has a type.
731    // however, if the result of the stmt expr is dead, we don't want to emit a
732    // warning.
733    const CompoundStmt *CS = cast<StmtExpr>(this)->getSubStmt();
734    if (!CS->body_empty())
735      if (const Expr *E = dyn_cast<Expr>(CS->body_back()))
736        return E->isUnusedResultAWarning(Loc, R1, R2);
737
738    Loc = cast<StmtExpr>(this)->getLParenLoc();
739    R1 = getSourceRange();
740    return true;
741  }
742  case CStyleCastExprClass:
743    // If this is an explicit cast to void, allow it.  People do this when they
744    // think they know what they're doing :).
745    if (getType()->isVoidType())
746      return false;
747    Loc = cast<CStyleCastExpr>(this)->getLParenLoc();
748    R1 = cast<CStyleCastExpr>(this)->getSubExpr()->getSourceRange();
749    return true;
750  case CXXFunctionalCastExprClass:
751    // If this is a cast to void, check the operand.  Otherwise, the result of
752    // the cast is unused.
753    if (getType()->isVoidType())
754      return cast<CastExpr>(this)->getSubExpr()
755               ->isUnusedResultAWarning(Loc, R1, R2);
756    Loc = cast<CXXFunctionalCastExpr>(this)->getTypeBeginLoc();
757    R1 = cast<CXXFunctionalCastExpr>(this)->getSubExpr()->getSourceRange();
758    return true;
759
760  case ImplicitCastExprClass:
761    // Check the operand, since implicit casts are inserted by Sema
762    return cast<ImplicitCastExpr>(this)
763      ->getSubExpr()->isUnusedResultAWarning(Loc, R1, R2);
764
765  case CXXDefaultArgExprClass:
766    return cast<CXXDefaultArgExpr>(this)
767      ->getExpr()->isUnusedResultAWarning(Loc, R1, R2);
768
769  case CXXNewExprClass:
770    // FIXME: In theory, there might be new expressions that don't have side
771    // effects (e.g. a placement new with an uninitialized POD).
772  case CXXDeleteExprClass:
773    return false;
774  case CXXBindTemporaryExprClass:
775    return cast<CXXBindTemporaryExpr>(this)
776      ->getSubExpr()->isUnusedResultAWarning(Loc, R1, R2);
777  case CXXExprWithTemporariesClass:
778    return cast<CXXExprWithTemporaries>(this)
779      ->getSubExpr()->isUnusedResultAWarning(Loc, R1, R2);
780  }
781}
782
783/// DeclCanBeLvalue - Determine whether the given declaration can be
784/// an lvalue. This is a helper routine for isLvalue.
785static bool DeclCanBeLvalue(const NamedDecl *Decl, ASTContext &Ctx) {
786  // C++ [temp.param]p6:
787  //   A non-type non-reference template-parameter is not an lvalue.
788  if (const NonTypeTemplateParmDecl *NTTParm
789        = dyn_cast<NonTypeTemplateParmDecl>(Decl))
790    return NTTParm->getType()->isReferenceType();
791
792  return isa<VarDecl>(Decl) || isa<FieldDecl>(Decl) ||
793    // C++ 3.10p2: An lvalue refers to an object or function.
794    (Ctx.getLangOptions().CPlusPlus &&
795     (isa<FunctionDecl>(Decl) || isa<OverloadedFunctionDecl>(Decl) ||
796      isa<FunctionTemplateDecl>(Decl)));
797}
798
799/// isLvalue - C99 6.3.2.1: an lvalue is an expression with an object type or an
800/// incomplete type other than void. Nonarray expressions that can be lvalues:
801///  - name, where name must be a variable
802///  - e[i]
803///  - (e), where e must be an lvalue
804///  - e.name, where e must be an lvalue
805///  - e->name
806///  - *e, the type of e cannot be a function type
807///  - string-constant
808///  - (__real__ e) and (__imag__ e) where e is an lvalue  [GNU extension]
809///  - reference type [C++ [expr]]
810///
811Expr::isLvalueResult Expr::isLvalue(ASTContext &Ctx) const {
812  assert(!TR->isReferenceType() && "Expressions can't have reference type.");
813
814  isLvalueResult Res = isLvalueInternal(Ctx);
815  if (Res != LV_Valid || Ctx.getLangOptions().CPlusPlus)
816    return Res;
817
818  // first, check the type (C99 6.3.2.1). Expressions with function
819  // type in C are not lvalues, but they can be lvalues in C++.
820  if (TR->isFunctionType() || TR == Ctx.OverloadTy)
821    return LV_NotObjectType;
822
823  // Allow qualified void which is an incomplete type other than void (yuck).
824  if (TR->isVoidType() && !Ctx.getCanonicalType(TR).getCVRQualifiers())
825    return LV_IncompleteVoidType;
826
827  return LV_Valid;
828}
829
830// Check whether the expression can be sanely treated like an l-value
831Expr::isLvalueResult Expr::isLvalueInternal(ASTContext &Ctx) const {
832  switch (getStmtClass()) {
833  case StringLiteralClass:  // C99 6.5.1p4
834  case ObjCEncodeExprClass: // @encode behaves like its string in every way.
835    return LV_Valid;
836  case ArraySubscriptExprClass: // C99 6.5.3p4 (e1[e2] == (*((e1)+(e2))))
837    // For vectors, make sure base is an lvalue (i.e. not a function call).
838    if (cast<ArraySubscriptExpr>(this)->getBase()->getType()->isVectorType())
839      return cast<ArraySubscriptExpr>(this)->getBase()->isLvalue(Ctx);
840    return LV_Valid;
841  case DeclRefExprClass:
842  case QualifiedDeclRefExprClass: { // C99 6.5.1p2
843    const NamedDecl *RefdDecl = cast<DeclRefExpr>(this)->getDecl();
844    if (DeclCanBeLvalue(RefdDecl, Ctx))
845      return LV_Valid;
846    break;
847  }
848  case BlockDeclRefExprClass: {
849    const BlockDeclRefExpr *BDR = cast<BlockDeclRefExpr>(this);
850    if (isa<VarDecl>(BDR->getDecl()))
851      return LV_Valid;
852    break;
853  }
854  case MemberExprClass: {
855    const MemberExpr *m = cast<MemberExpr>(this);
856    if (Ctx.getLangOptions().CPlusPlus) { // C++ [expr.ref]p4:
857      NamedDecl *Member = m->getMemberDecl();
858      // C++ [expr.ref]p4:
859      //   If E2 is declared to have type "reference to T", then E1.E2
860      //   is an lvalue.
861      if (ValueDecl *Value = dyn_cast<ValueDecl>(Member))
862        if (Value->getType()->isReferenceType())
863          return LV_Valid;
864
865      //   -- If E2 is a static data member [...] then E1.E2 is an lvalue.
866      if (isa<VarDecl>(Member) && Member->getDeclContext()->isRecord())
867        return LV_Valid;
868
869      //   -- If E2 is a non-static data member [...]. If E1 is an
870      //      lvalue, then E1.E2 is an lvalue.
871      if (isa<FieldDecl>(Member))
872        return m->isArrow() ? LV_Valid : m->getBase()->isLvalue(Ctx);
873
874      //   -- If it refers to a static member function [...], then
875      //      E1.E2 is an lvalue.
876      //   -- Otherwise, if E1.E2 refers to a non-static member
877      //      function [...], then E1.E2 is not an lvalue.
878      if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Member))
879        return Method->isStatic()? LV_Valid : LV_MemberFunction;
880
881      //   -- If E2 is a member enumerator [...], the expression E1.E2
882      //      is not an lvalue.
883      if (isa<EnumConstantDecl>(Member))
884        return LV_InvalidExpression;
885
886        // Not an lvalue.
887      return LV_InvalidExpression;
888    }
889
890    // C99 6.5.2.3p4
891    return m->isArrow() ? LV_Valid : m->getBase()->isLvalue(Ctx);
892  }
893  case UnaryOperatorClass:
894    if (cast<UnaryOperator>(this)->getOpcode() == UnaryOperator::Deref)
895      return LV_Valid; // C99 6.5.3p4
896
897    if (cast<UnaryOperator>(this)->getOpcode() == UnaryOperator::Real ||
898        cast<UnaryOperator>(this)->getOpcode() == UnaryOperator::Imag ||
899        cast<UnaryOperator>(this)->getOpcode() == UnaryOperator::Extension)
900      return cast<UnaryOperator>(this)->getSubExpr()->isLvalue(Ctx);  // GNU.
901
902    if (Ctx.getLangOptions().CPlusPlus && // C++ [expr.pre.incr]p1
903        (cast<UnaryOperator>(this)->getOpcode() == UnaryOperator::PreInc ||
904         cast<UnaryOperator>(this)->getOpcode() == UnaryOperator::PreDec))
905      return LV_Valid;
906    break;
907  case ImplicitCastExprClass:
908    return cast<ImplicitCastExpr>(this)->isLvalueCast()? LV_Valid
909                                                       : LV_InvalidExpression;
910  case ParenExprClass: // C99 6.5.1p5
911    return cast<ParenExpr>(this)->getSubExpr()->isLvalue(Ctx);
912  case BinaryOperatorClass:
913  case CompoundAssignOperatorClass: {
914    const BinaryOperator *BinOp = cast<BinaryOperator>(this);
915
916    if (Ctx.getLangOptions().CPlusPlus && // C++ [expr.comma]p1
917        BinOp->getOpcode() == BinaryOperator::Comma)
918      return BinOp->getRHS()->isLvalue(Ctx);
919
920    // C++ [expr.mptr.oper]p6
921    if ((BinOp->getOpcode() == BinaryOperator::PtrMemD ||
922         BinOp->getOpcode() == BinaryOperator::PtrMemI) &&
923        !BinOp->getType()->isFunctionType())
924      return BinOp->getLHS()->isLvalue(Ctx);
925
926    if (!BinOp->isAssignmentOp())
927      return LV_InvalidExpression;
928
929    if (Ctx.getLangOptions().CPlusPlus)
930      // C++ [expr.ass]p1:
931      //   The result of an assignment operation [...] is an lvalue.
932      return LV_Valid;
933
934
935    // C99 6.5.16:
936    //   An assignment expression [...] is not an lvalue.
937    return LV_InvalidExpression;
938  }
939  case CallExprClass:
940  case CXXOperatorCallExprClass:
941  case CXXMemberCallExprClass: {
942    // C++0x [expr.call]p10
943    //   A function call is an lvalue if and only if the result type
944    //   is an lvalue reference.
945    QualType ReturnType = cast<CallExpr>(this)->getCallReturnType();
946    if (ReturnType->isLValueReferenceType())
947      return LV_Valid;
948
949    break;
950  }
951  case CompoundLiteralExprClass: // C99 6.5.2.5p5
952    return LV_Valid;
953  case ChooseExprClass:
954    // __builtin_choose_expr is an lvalue if the selected operand is.
955    return cast<ChooseExpr>(this)->getChosenSubExpr(Ctx)->isLvalue(Ctx);
956  case ExtVectorElementExprClass:
957    if (cast<ExtVectorElementExpr>(this)->containsDuplicateElements())
958      return LV_DuplicateVectorComponents;
959    return LV_Valid;
960  case ObjCIvarRefExprClass: // ObjC instance variables are lvalues.
961    return LV_Valid;
962  case ObjCPropertyRefExprClass: // FIXME: check if read-only property.
963    return LV_Valid;
964  case ObjCImplicitSetterGetterRefExprClass: // FIXME: check if read-only property.
965    return LV_Valid;
966  case PredefinedExprClass:
967    return LV_Valid;
968  case CXXDefaultArgExprClass:
969    return cast<CXXDefaultArgExpr>(this)->getExpr()->isLvalue(Ctx);
970  case CXXConditionDeclExprClass:
971    return LV_Valid;
972  case CStyleCastExprClass:
973  case CXXFunctionalCastExprClass:
974  case CXXStaticCastExprClass:
975  case CXXDynamicCastExprClass:
976  case CXXReinterpretCastExprClass:
977  case CXXConstCastExprClass:
978    // The result of an explicit cast is an lvalue if the type we are
979    // casting to is an lvalue reference type. See C++ [expr.cast]p1,
980    // C++ [expr.static.cast]p2, C++ [expr.dynamic.cast]p2,
981    // C++ [expr.reinterpret.cast]p1, C++ [expr.const.cast]p1.
982    if (cast<ExplicitCastExpr>(this)->getTypeAsWritten()->
983          isLValueReferenceType())
984      return LV_Valid;
985    break;
986  case CXXTypeidExprClass:
987    // C++ 5.2.8p1: The result of a typeid expression is an lvalue of ...
988    return LV_Valid;
989  case CXXBindTemporaryExprClass:
990    return cast<CXXBindTemporaryExpr>(this)->getSubExpr()->
991      isLvalueInternal(Ctx);
992  case ConditionalOperatorClass: {
993    // Complicated handling is only for C++.
994    if (!Ctx.getLangOptions().CPlusPlus)
995      return LV_InvalidExpression;
996
997    // Sema should have taken care to ensure that a CXXTemporaryObjectExpr is
998    // everywhere there's an object converted to an rvalue. Also, any other
999    // casts should be wrapped by ImplicitCastExprs. There's just the special
1000    // case involving throws to work out.
1001    const ConditionalOperator *Cond = cast<ConditionalOperator>(this);
1002    Expr *True = Cond->getTrueExpr();
1003    Expr *False = Cond->getFalseExpr();
1004    // C++0x 5.16p2
1005    //   If either the second or the third operand has type (cv) void, [...]
1006    //   the result [...] is an rvalue.
1007    if (True->getType()->isVoidType() || False->getType()->isVoidType())
1008      return LV_InvalidExpression;
1009
1010    // Both sides must be lvalues for the result to be an lvalue.
1011    if (True->isLvalue(Ctx) != LV_Valid || False->isLvalue(Ctx) != LV_Valid)
1012      return LV_InvalidExpression;
1013
1014    // That's it.
1015    return LV_Valid;
1016  }
1017
1018  default:
1019    break;
1020  }
1021  return LV_InvalidExpression;
1022}
1023
1024/// isModifiableLvalue - C99 6.3.2.1: an lvalue that does not have array type,
1025/// does not have an incomplete type, does not have a const-qualified type, and
1026/// if it is a structure or union, does not have any member (including,
1027/// recursively, any member or element of all contained aggregates or unions)
1028/// with a const-qualified type.
1029Expr::isModifiableLvalueResult
1030Expr::isModifiableLvalue(ASTContext &Ctx, SourceLocation *Loc) const {
1031  isLvalueResult lvalResult = isLvalue(Ctx);
1032
1033  switch (lvalResult) {
1034  case LV_Valid:
1035    // C++ 3.10p11: Functions cannot be modified, but pointers to
1036    // functions can be modifiable.
1037    if (Ctx.getLangOptions().CPlusPlus && TR->isFunctionType())
1038      return MLV_NotObjectType;
1039    break;
1040
1041  case LV_NotObjectType: return MLV_NotObjectType;
1042  case LV_IncompleteVoidType: return MLV_IncompleteVoidType;
1043  case LV_DuplicateVectorComponents: return MLV_DuplicateVectorComponents;
1044  case LV_InvalidExpression:
1045    // If the top level is a C-style cast, and the subexpression is a valid
1046    // lvalue, then this is probably a use of the old-school "cast as lvalue"
1047    // GCC extension.  We don't support it, but we want to produce good
1048    // diagnostics when it happens so that the user knows why.
1049    if (const CStyleCastExpr *CE = dyn_cast<CStyleCastExpr>(IgnoreParens())) {
1050      if (CE->getSubExpr()->isLvalue(Ctx) == LV_Valid) {
1051        if (Loc)
1052          *Loc = CE->getLParenLoc();
1053        return MLV_LValueCast;
1054      }
1055    }
1056    return MLV_InvalidExpression;
1057  case LV_MemberFunction: return MLV_MemberFunction;
1058  }
1059
1060  // The following is illegal:
1061  //   void takeclosure(void (^C)(void));
1062  //   void func() { int x = 1; takeclosure(^{ x = 7; }); }
1063  //
1064  if (isa<BlockDeclRefExpr>(this)) {
1065    const BlockDeclRefExpr *BDR = cast<BlockDeclRefExpr>(this);
1066    if (!BDR->isByRef() && isa<VarDecl>(BDR->getDecl()))
1067      return MLV_NotBlockQualified;
1068  }
1069
1070  QualType CT = Ctx.getCanonicalType(getType());
1071
1072  if (CT.isConstQualified())
1073    return MLV_ConstQualified;
1074  if (CT->isArrayType())
1075    return MLV_ArrayType;
1076  if (CT->isIncompleteType())
1077    return MLV_IncompleteType;
1078
1079  if (const RecordType *r = CT->getAs<RecordType>()) {
1080    if (r->hasConstFields())
1081      return MLV_ConstQualified;
1082  }
1083
1084  // Assigning to an 'implicit' property?
1085  else if (isa<ObjCImplicitSetterGetterRefExpr>(this)) {
1086    const ObjCImplicitSetterGetterRefExpr* Expr =
1087      cast<ObjCImplicitSetterGetterRefExpr>(this);
1088    if (Expr->getSetterMethod() == 0)
1089      return MLV_NoSetterProperty;
1090  }
1091  return MLV_Valid;
1092}
1093
1094/// isOBJCGCCandidate - Check if an expression is objc gc'able.
1095/// returns true, if it is; false otherwise.
1096bool Expr::isOBJCGCCandidate(ASTContext &Ctx) const {
1097  switch (getStmtClass()) {
1098  default:
1099    return false;
1100  case ObjCIvarRefExprClass:
1101    return true;
1102  case Expr::UnaryOperatorClass:
1103    return cast<UnaryOperator>(this)->getSubExpr()->isOBJCGCCandidate(Ctx);
1104  case ParenExprClass:
1105    return cast<ParenExpr>(this)->getSubExpr()->isOBJCGCCandidate(Ctx);
1106  case ImplicitCastExprClass:
1107    return cast<ImplicitCastExpr>(this)->getSubExpr()->isOBJCGCCandidate(Ctx);
1108  case CStyleCastExprClass:
1109    return cast<CStyleCastExpr>(this)->getSubExpr()->isOBJCGCCandidate(Ctx);
1110  case DeclRefExprClass:
1111  case QualifiedDeclRefExprClass: {
1112    const Decl *D = cast<DeclRefExpr>(this)->getDecl();
1113    if (const VarDecl *VD = dyn_cast<VarDecl>(D)) {
1114      if (VD->hasGlobalStorage())
1115        return true;
1116      QualType T = VD->getType();
1117      // dereferencing to a pointer is always a gc'able candidate
1118      return T->isPointerType();
1119    }
1120    return false;
1121  }
1122  case MemberExprClass: {
1123    const MemberExpr *M = cast<MemberExpr>(this);
1124    return M->getBase()->isOBJCGCCandidate(Ctx);
1125  }
1126  case ArraySubscriptExprClass:
1127    return cast<ArraySubscriptExpr>(this)->getBase()->isOBJCGCCandidate(Ctx);
1128  }
1129}
1130Expr* Expr::IgnoreParens() {
1131  Expr* E = this;
1132  while (ParenExpr* P = dyn_cast<ParenExpr>(E))
1133    E = P->getSubExpr();
1134
1135  return E;
1136}
1137
1138/// IgnoreParenCasts - Ignore parentheses and casts.  Strip off any ParenExpr
1139/// or CastExprs or ImplicitCastExprs, returning their operand.
1140Expr *Expr::IgnoreParenCasts() {
1141  Expr *E = this;
1142  while (true) {
1143    if (ParenExpr *P = dyn_cast<ParenExpr>(E))
1144      E = P->getSubExpr();
1145    else if (CastExpr *P = dyn_cast<CastExpr>(E))
1146      E = P->getSubExpr();
1147    else
1148      return E;
1149  }
1150}
1151
1152/// IgnoreParenNoopCasts - Ignore parentheses and casts that do not change the
1153/// value (including ptr->int casts of the same size).  Strip off any
1154/// ParenExpr or CastExprs, returning their operand.
1155Expr *Expr::IgnoreParenNoopCasts(ASTContext &Ctx) {
1156  Expr *E = this;
1157  while (true) {
1158    if (ParenExpr *P = dyn_cast<ParenExpr>(E)) {
1159      E = P->getSubExpr();
1160      continue;
1161    }
1162
1163    if (CastExpr *P = dyn_cast<CastExpr>(E)) {
1164      // We ignore integer <-> casts that are of the same width, ptr<->ptr and
1165      // ptr<->int casts of the same width.  We also ignore all identify casts.
1166      Expr *SE = P->getSubExpr();
1167
1168      if (Ctx.hasSameUnqualifiedType(E->getType(), SE->getType())) {
1169        E = SE;
1170        continue;
1171      }
1172
1173      if ((E->getType()->isPointerType() || E->getType()->isIntegralType()) &&
1174          (SE->getType()->isPointerType() || SE->getType()->isIntegralType()) &&
1175          Ctx.getTypeSize(E->getType()) == Ctx.getTypeSize(SE->getType())) {
1176        E = SE;
1177        continue;
1178      }
1179    }
1180
1181    return E;
1182  }
1183}
1184
1185
1186/// hasAnyTypeDependentArguments - Determines if any of the expressions
1187/// in Exprs is type-dependent.
1188bool Expr::hasAnyTypeDependentArguments(Expr** Exprs, unsigned NumExprs) {
1189  for (unsigned I = 0; I < NumExprs; ++I)
1190    if (Exprs[I]->isTypeDependent())
1191      return true;
1192
1193  return false;
1194}
1195
1196/// hasAnyValueDependentArguments - Determines if any of the expressions
1197/// in Exprs is value-dependent.
1198bool Expr::hasAnyValueDependentArguments(Expr** Exprs, unsigned NumExprs) {
1199  for (unsigned I = 0; I < NumExprs; ++I)
1200    if (Exprs[I]->isValueDependent())
1201      return true;
1202
1203  return false;
1204}
1205
1206bool Expr::isConstantInitializer(ASTContext &Ctx) const {
1207  // This function is attempting whether an expression is an initializer
1208  // which can be evaluated at compile-time.  isEvaluatable handles most
1209  // of the cases, but it can't deal with some initializer-specific
1210  // expressions, and it can't deal with aggregates; we deal with those here,
1211  // and fall back to isEvaluatable for the other cases.
1212
1213  // FIXME: This function assumes the variable being assigned to
1214  // isn't a reference type!
1215
1216  switch (getStmtClass()) {
1217  default: break;
1218  case StringLiteralClass:
1219  case ObjCStringLiteralClass:
1220  case ObjCEncodeExprClass:
1221    return true;
1222  case CompoundLiteralExprClass: {
1223    // This handles gcc's extension that allows global initializers like
1224    // "struct x {int x;} x = (struct x) {};".
1225    // FIXME: This accepts other cases it shouldn't!
1226    const Expr *Exp = cast<CompoundLiteralExpr>(this)->getInitializer();
1227    return Exp->isConstantInitializer(Ctx);
1228  }
1229  case InitListExprClass: {
1230    // FIXME: This doesn't deal with fields with reference types correctly.
1231    // FIXME: This incorrectly allows pointers cast to integers to be assigned
1232    // to bitfields.
1233    const InitListExpr *Exp = cast<InitListExpr>(this);
1234    unsigned numInits = Exp->getNumInits();
1235    for (unsigned i = 0; i < numInits; i++) {
1236      if (!Exp->getInit(i)->isConstantInitializer(Ctx))
1237        return false;
1238    }
1239    return true;
1240  }
1241  case ImplicitValueInitExprClass:
1242    return true;
1243  case ParenExprClass: {
1244    return cast<ParenExpr>(this)->getSubExpr()->isConstantInitializer(Ctx);
1245  }
1246  case UnaryOperatorClass: {
1247    const UnaryOperator* Exp = cast<UnaryOperator>(this);
1248    if (Exp->getOpcode() == UnaryOperator::Extension)
1249      return Exp->getSubExpr()->isConstantInitializer(Ctx);
1250    break;
1251  }
1252  case ImplicitCastExprClass:
1253  case CStyleCastExprClass:
1254    // Handle casts with a destination that's a struct or union; this
1255    // deals with both the gcc no-op struct cast extension and the
1256    // cast-to-union extension.
1257    if (getType()->isRecordType())
1258      return cast<CastExpr>(this)->getSubExpr()->isConstantInitializer(Ctx);
1259    break;
1260  }
1261  return isEvaluatable(Ctx);
1262}
1263
1264/// isIntegerConstantExpr - this recursive routine will test if an expression is
1265/// an integer constant expression.
1266
1267/// FIXME: Pass up a reason why! Invalid operation in i-c-e, division by zero,
1268/// comma, etc
1269///
1270/// FIXME: Handle offsetof.  Two things to do:  Handle GCC's __builtin_offsetof
1271/// to support gcc 4.0+  and handle the idiom GCC recognizes with a null pointer
1272/// cast+dereference.
1273
1274// CheckICE - This function does the fundamental ICE checking: the returned
1275// ICEDiag contains a Val of 0, 1, or 2, and a possibly null SourceLocation.
1276// Note that to reduce code duplication, this helper does no evaluation
1277// itself; the caller checks whether the expression is evaluatable, and
1278// in the rare cases where CheckICE actually cares about the evaluated
1279// value, it calls into Evalute.
1280//
1281// Meanings of Val:
1282// 0: This expression is an ICE if it can be evaluated by Evaluate.
1283// 1: This expression is not an ICE, but if it isn't evaluated, it's
1284//    a legal subexpression for an ICE. This return value is used to handle
1285//    the comma operator in C99 mode.
1286// 2: This expression is not an ICE, and is not a legal subexpression for one.
1287
1288struct ICEDiag {
1289  unsigned Val;
1290  SourceLocation Loc;
1291
1292  public:
1293  ICEDiag(unsigned v, SourceLocation l) : Val(v), Loc(l) {}
1294  ICEDiag() : Val(0) {}
1295};
1296
1297ICEDiag NoDiag() { return ICEDiag(); }
1298
1299static ICEDiag CheckEvalInICE(const Expr* E, ASTContext &Ctx) {
1300  Expr::EvalResult EVResult;
1301  if (!E->Evaluate(EVResult, Ctx) || EVResult.HasSideEffects ||
1302      !EVResult.Val.isInt()) {
1303    return ICEDiag(2, E->getLocStart());
1304  }
1305  return NoDiag();
1306}
1307
1308static ICEDiag CheckICE(const Expr* E, ASTContext &Ctx) {
1309  assert(!E->isValueDependent() && "Should not see value dependent exprs!");
1310  if (!E->getType()->isIntegralType()) {
1311    return ICEDiag(2, E->getLocStart());
1312  }
1313
1314  switch (E->getStmtClass()) {
1315  default:
1316    return ICEDiag(2, E->getLocStart());
1317  case Expr::ParenExprClass:
1318    return CheckICE(cast<ParenExpr>(E)->getSubExpr(), Ctx);
1319  case Expr::IntegerLiteralClass:
1320  case Expr::CharacterLiteralClass:
1321  case Expr::CXXBoolLiteralExprClass:
1322  case Expr::CXXZeroInitValueExprClass:
1323  case Expr::TypesCompatibleExprClass:
1324  case Expr::UnaryTypeTraitExprClass:
1325    return NoDiag();
1326  case Expr::CallExprClass:
1327  case Expr::CXXOperatorCallExprClass: {
1328    const CallExpr *CE = cast<CallExpr>(E);
1329    if (CE->isBuiltinCall(Ctx))
1330      return CheckEvalInICE(E, Ctx);
1331    return ICEDiag(2, E->getLocStart());
1332  }
1333  case Expr::DeclRefExprClass:
1334  case Expr::QualifiedDeclRefExprClass:
1335    if (isa<EnumConstantDecl>(cast<DeclRefExpr>(E)->getDecl()))
1336      return NoDiag();
1337    if (Ctx.getLangOptions().CPlusPlus &&
1338        E->getType().getCVRQualifiers() == QualType::Const) {
1339      // C++ 7.1.5.1p2
1340      //   A variable of non-volatile const-qualified integral or enumeration
1341      //   type initialized by an ICE can be used in ICEs.
1342      if (const VarDecl *Dcl =
1343              dyn_cast<VarDecl>(cast<DeclRefExpr>(E)->getDecl())) {
1344        if (Dcl->isInitKnownICE()) {
1345          // We have already checked whether this subexpression is an
1346          // integral constant expression.
1347          if (Dcl->isInitICE())
1348            return NoDiag();
1349          else
1350            return ICEDiag(2, E->getLocStart());
1351        }
1352
1353        if (const Expr *Init = Dcl->getInit()) {
1354          ICEDiag Result = CheckICE(Init, Ctx);
1355          // Cache the result of the ICE test.
1356          Dcl->setInitKnownICE(Ctx, Result.Val == 0);
1357          return Result;
1358        }
1359      }
1360    }
1361    return ICEDiag(2, E->getLocStart());
1362  case Expr::UnaryOperatorClass: {
1363    const UnaryOperator *Exp = cast<UnaryOperator>(E);
1364    switch (Exp->getOpcode()) {
1365    default:
1366      return ICEDiag(2, E->getLocStart());
1367    case UnaryOperator::Extension:
1368    case UnaryOperator::LNot:
1369    case UnaryOperator::Plus:
1370    case UnaryOperator::Minus:
1371    case UnaryOperator::Not:
1372    case UnaryOperator::Real:
1373    case UnaryOperator::Imag:
1374      return CheckICE(Exp->getSubExpr(), Ctx);
1375    case UnaryOperator::OffsetOf:
1376      // Note that per C99, offsetof must be an ICE. And AFAIK, using
1377      // Evaluate matches the proposed gcc behavior for cases like
1378      // "offsetof(struct s{int x[4];}, x[!.0])".  This doesn't affect
1379      // compliance: we should warn earlier for offsetof expressions with
1380      // array subscripts that aren't ICEs, and if the array subscripts
1381      // are ICEs, the value of the offsetof must be an integer constant.
1382      return CheckEvalInICE(E, Ctx);
1383    }
1384  }
1385  case Expr::SizeOfAlignOfExprClass: {
1386    const SizeOfAlignOfExpr *Exp = cast<SizeOfAlignOfExpr>(E);
1387    if (Exp->isSizeOf() && Exp->getTypeOfArgument()->isVariableArrayType())
1388      return ICEDiag(2, E->getLocStart());
1389    return NoDiag();
1390  }
1391  case Expr::BinaryOperatorClass: {
1392    const BinaryOperator *Exp = cast<BinaryOperator>(E);
1393    switch (Exp->getOpcode()) {
1394    default:
1395      return ICEDiag(2, E->getLocStart());
1396    case BinaryOperator::Mul:
1397    case BinaryOperator::Div:
1398    case BinaryOperator::Rem:
1399    case BinaryOperator::Add:
1400    case BinaryOperator::Sub:
1401    case BinaryOperator::Shl:
1402    case BinaryOperator::Shr:
1403    case BinaryOperator::LT:
1404    case BinaryOperator::GT:
1405    case BinaryOperator::LE:
1406    case BinaryOperator::GE:
1407    case BinaryOperator::EQ:
1408    case BinaryOperator::NE:
1409    case BinaryOperator::And:
1410    case BinaryOperator::Xor:
1411    case BinaryOperator::Or:
1412    case BinaryOperator::Comma: {
1413      ICEDiag LHSResult = CheckICE(Exp->getLHS(), Ctx);
1414      ICEDiag RHSResult = CheckICE(Exp->getRHS(), Ctx);
1415      if (Exp->getOpcode() == BinaryOperator::Div ||
1416          Exp->getOpcode() == BinaryOperator::Rem) {
1417        // Evaluate gives an error for undefined Div/Rem, so make sure
1418        // we don't evaluate one.
1419        if (LHSResult.Val != 2 && RHSResult.Val != 2) {
1420          llvm::APSInt REval = Exp->getRHS()->EvaluateAsInt(Ctx);
1421          if (REval == 0)
1422            return ICEDiag(1, E->getLocStart());
1423          if (REval.isSigned() && REval.isAllOnesValue()) {
1424            llvm::APSInt LEval = Exp->getLHS()->EvaluateAsInt(Ctx);
1425            if (LEval.isMinSignedValue())
1426              return ICEDiag(1, E->getLocStart());
1427          }
1428        }
1429      }
1430      if (Exp->getOpcode() == BinaryOperator::Comma) {
1431        if (Ctx.getLangOptions().C99) {
1432          // C99 6.6p3 introduces a strange edge case: comma can be in an ICE
1433          // if it isn't evaluated.
1434          if (LHSResult.Val == 0 && RHSResult.Val == 0)
1435            return ICEDiag(1, E->getLocStart());
1436        } else {
1437          // In both C89 and C++, commas in ICEs are illegal.
1438          return ICEDiag(2, E->getLocStart());
1439        }
1440      }
1441      if (LHSResult.Val >= RHSResult.Val)
1442        return LHSResult;
1443      return RHSResult;
1444    }
1445    case BinaryOperator::LAnd:
1446    case BinaryOperator::LOr: {
1447      ICEDiag LHSResult = CheckICE(Exp->getLHS(), Ctx);
1448      ICEDiag RHSResult = CheckICE(Exp->getRHS(), Ctx);
1449      if (LHSResult.Val == 0 && RHSResult.Val == 1) {
1450        // Rare case where the RHS has a comma "side-effect"; we need
1451        // to actually check the condition to see whether the side
1452        // with the comma is evaluated.
1453        if ((Exp->getOpcode() == BinaryOperator::LAnd) !=
1454            (Exp->getLHS()->EvaluateAsInt(Ctx) == 0))
1455          return RHSResult;
1456        return NoDiag();
1457      }
1458
1459      if (LHSResult.Val >= RHSResult.Val)
1460        return LHSResult;
1461      return RHSResult;
1462    }
1463    }
1464  }
1465  case Expr::ImplicitCastExprClass:
1466  case Expr::CStyleCastExprClass:
1467  case Expr::CXXFunctionalCastExprClass: {
1468    const Expr *SubExpr = cast<CastExpr>(E)->getSubExpr();
1469    if (SubExpr->getType()->isIntegralType())
1470      return CheckICE(SubExpr, Ctx);
1471    if (isa<FloatingLiteral>(SubExpr->IgnoreParens()))
1472      return NoDiag();
1473    return ICEDiag(2, E->getLocStart());
1474  }
1475  case Expr::ConditionalOperatorClass: {
1476    const ConditionalOperator *Exp = cast<ConditionalOperator>(E);
1477    // If the condition (ignoring parens) is a __builtin_constant_p call,
1478    // then only the true side is actually considered in an integer constant
1479    // expression, and it is fully evaluated.  This is an important GNU
1480    // extension.  See GCC PR38377 for discussion.
1481    if (const CallExpr *CallCE = dyn_cast<CallExpr>(Exp->getCond()->IgnoreParenCasts()))
1482      if (CallCE->isBuiltinCall(Ctx) == Builtin::BI__builtin_constant_p) {
1483        Expr::EvalResult EVResult;
1484        if (!E->Evaluate(EVResult, Ctx) || EVResult.HasSideEffects ||
1485            !EVResult.Val.isInt()) {
1486          return ICEDiag(2, E->getLocStart());
1487        }
1488        return NoDiag();
1489      }
1490    ICEDiag CondResult = CheckICE(Exp->getCond(), Ctx);
1491    ICEDiag TrueResult = CheckICE(Exp->getTrueExpr(), Ctx);
1492    ICEDiag FalseResult = CheckICE(Exp->getFalseExpr(), Ctx);
1493    if (CondResult.Val == 2)
1494      return CondResult;
1495    if (TrueResult.Val == 2)
1496      return TrueResult;
1497    if (FalseResult.Val == 2)
1498      return FalseResult;
1499    if (CondResult.Val == 1)
1500      return CondResult;
1501    if (TrueResult.Val == 0 && FalseResult.Val == 0)
1502      return NoDiag();
1503    // Rare case where the diagnostics depend on which side is evaluated
1504    // Note that if we get here, CondResult is 0, and at least one of
1505    // TrueResult and FalseResult is non-zero.
1506    if (Exp->getCond()->EvaluateAsInt(Ctx) == 0) {
1507      return FalseResult;
1508    }
1509    return TrueResult;
1510  }
1511  case Expr::CXXDefaultArgExprClass:
1512    return CheckICE(cast<CXXDefaultArgExpr>(E)->getExpr(), Ctx);
1513  case Expr::ChooseExprClass: {
1514    return CheckICE(cast<ChooseExpr>(E)->getChosenSubExpr(Ctx), Ctx);
1515  }
1516  }
1517}
1518
1519bool Expr::isIntegerConstantExpr(llvm::APSInt &Result, ASTContext &Ctx,
1520                                 SourceLocation *Loc, bool isEvaluated) const {
1521  ICEDiag d = CheckICE(this, Ctx);
1522  if (d.Val != 0) {
1523    if (Loc) *Loc = d.Loc;
1524    return false;
1525  }
1526  EvalResult EvalResult;
1527  if (!Evaluate(EvalResult, Ctx))
1528    assert(0 && "ICE cannot be evaluated!");
1529  assert(!EvalResult.HasSideEffects && "ICE with side effects!");
1530  assert(EvalResult.Val.isInt() && "ICE that isn't integer!");
1531  Result = EvalResult.Val.getInt();
1532  return true;
1533}
1534
1535/// isNullPointerConstant - C99 6.3.2.3p3 -  Return true if this is either an
1536/// integer constant expression with the value zero, or if this is one that is
1537/// cast to void*.
1538bool Expr::isNullPointerConstant(ASTContext &Ctx) const
1539{
1540  // Strip off a cast to void*, if it exists. Except in C++.
1541  if (const ExplicitCastExpr *CE = dyn_cast<ExplicitCastExpr>(this)) {
1542    if (!Ctx.getLangOptions().CPlusPlus) {
1543      // Check that it is a cast to void*.
1544      if (const PointerType *PT = CE->getType()->getAs<PointerType>()) {
1545        QualType Pointee = PT->getPointeeType();
1546        if (Pointee.getCVRQualifiers() == 0 &&
1547            Pointee->isVoidType() &&                              // to void*
1548            CE->getSubExpr()->getType()->isIntegerType())         // from int.
1549          return CE->getSubExpr()->isNullPointerConstant(Ctx);
1550      }
1551    }
1552  } else if (const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(this)) {
1553    // Ignore the ImplicitCastExpr type entirely.
1554    return ICE->getSubExpr()->isNullPointerConstant(Ctx);
1555  } else if (const ParenExpr *PE = dyn_cast<ParenExpr>(this)) {
1556    // Accept ((void*)0) as a null pointer constant, as many other
1557    // implementations do.
1558    return PE->getSubExpr()->isNullPointerConstant(Ctx);
1559  } else if (const CXXDefaultArgExpr *DefaultArg
1560               = dyn_cast<CXXDefaultArgExpr>(this)) {
1561    // See through default argument expressions
1562    return DefaultArg->getExpr()->isNullPointerConstant(Ctx);
1563  } else if (isa<GNUNullExpr>(this)) {
1564    // The GNU __null extension is always a null pointer constant.
1565    return true;
1566  }
1567
1568  // C++0x nullptr_t is always a null pointer constant.
1569  if (getType()->isNullPtrType())
1570    return true;
1571
1572  // This expression must be an integer type.
1573  if (!getType()->isIntegerType())
1574    return false;
1575
1576  // If we have an integer constant expression, we need to *evaluate* it and
1577  // test for the value 0.
1578  llvm::APSInt Result;
1579  return isIntegerConstantExpr(Result, Ctx) && Result == 0;
1580}
1581
1582FieldDecl *Expr::getBitField() {
1583  Expr *E = this->IgnoreParens();
1584
1585  if (MemberExpr *MemRef = dyn_cast<MemberExpr>(E))
1586    if (FieldDecl *Field = dyn_cast<FieldDecl>(MemRef->getMemberDecl()))
1587      if (Field->isBitField())
1588        return Field;
1589
1590  if (BinaryOperator *BinOp = dyn_cast<BinaryOperator>(E))
1591    if (BinOp->isAssignmentOp() && BinOp->getLHS())
1592      return BinOp->getLHS()->getBitField();
1593
1594  return 0;
1595}
1596
1597/// isArrow - Return true if the base expression is a pointer to vector,
1598/// return false if the base expression is a vector.
1599bool ExtVectorElementExpr::isArrow() const {
1600  return getBase()->getType()->isPointerType();
1601}
1602
1603unsigned ExtVectorElementExpr::getNumElements() const {
1604  if (const VectorType *VT = getType()->getAsVectorType())
1605    return VT->getNumElements();
1606  return 1;
1607}
1608
1609/// containsDuplicateElements - Return true if any element access is repeated.
1610bool ExtVectorElementExpr::containsDuplicateElements() const {
1611  const char *compStr = Accessor->getName();
1612  unsigned length = Accessor->getLength();
1613
1614  // Halving swizzles do not contain duplicate elements.
1615  if (!strcmp(compStr, "hi") || !strcmp(compStr, "lo") ||
1616      !strcmp(compStr, "even") || !strcmp(compStr, "odd"))
1617    return false;
1618
1619  // Advance past s-char prefix on hex swizzles.
1620  if (*compStr == 's' || *compStr == 'S') {
1621    compStr++;
1622    length--;
1623  }
1624
1625  for (unsigned i = 0; i != length-1; i++) {
1626    const char *s = compStr+i;
1627    for (const char c = *s++; *s; s++)
1628      if (c == *s)
1629        return true;
1630  }
1631  return false;
1632}
1633
1634/// getEncodedElementAccess - We encode the fields as a llvm ConstantArray.
1635void ExtVectorElementExpr::getEncodedElementAccess(
1636                                  llvm::SmallVectorImpl<unsigned> &Elts) const {
1637  const char *compStr = Accessor->getName();
1638  if (*compStr == 's' || *compStr == 'S')
1639    compStr++;
1640
1641  bool isHi =   !strcmp(compStr, "hi");
1642  bool isLo =   !strcmp(compStr, "lo");
1643  bool isEven = !strcmp(compStr, "even");
1644  bool isOdd  = !strcmp(compStr, "odd");
1645
1646  for (unsigned i = 0, e = getNumElements(); i != e; ++i) {
1647    uint64_t Index;
1648
1649    if (isHi)
1650      Index = e + i;
1651    else if (isLo)
1652      Index = i;
1653    else if (isEven)
1654      Index = 2 * i;
1655    else if (isOdd)
1656      Index = 2 * i + 1;
1657    else
1658      Index = ExtVectorType::getAccessorIdx(compStr[i]);
1659
1660    Elts.push_back(Index);
1661  }
1662}
1663
1664// constructor for instance messages.
1665ObjCMessageExpr::ObjCMessageExpr(Expr *receiver, Selector selInfo,
1666                QualType retType, ObjCMethodDecl *mproto,
1667                SourceLocation LBrac, SourceLocation RBrac,
1668                Expr **ArgExprs, unsigned nargs)
1669  : Expr(ObjCMessageExprClass, retType), SelName(selInfo),
1670    MethodProto(mproto) {
1671  NumArgs = nargs;
1672  SubExprs = new Stmt*[NumArgs+1];
1673  SubExprs[RECEIVER] = receiver;
1674  if (NumArgs) {
1675    for (unsigned i = 0; i != NumArgs; ++i)
1676      SubExprs[i+ARGS_START] = static_cast<Expr *>(ArgExprs[i]);
1677  }
1678  LBracloc = LBrac;
1679  RBracloc = RBrac;
1680}
1681
1682// constructor for class messages.
1683// FIXME: clsName should be typed to ObjCInterfaceType
1684ObjCMessageExpr::ObjCMessageExpr(IdentifierInfo *clsName, Selector selInfo,
1685                QualType retType, ObjCMethodDecl *mproto,
1686                SourceLocation LBrac, SourceLocation RBrac,
1687                Expr **ArgExprs, unsigned nargs)
1688  : Expr(ObjCMessageExprClass, retType), SelName(selInfo),
1689    MethodProto(mproto) {
1690  NumArgs = nargs;
1691  SubExprs = new Stmt*[NumArgs+1];
1692  SubExprs[RECEIVER] = (Expr*) ((uintptr_t) clsName | IsClsMethDeclUnknown);
1693  if (NumArgs) {
1694    for (unsigned i = 0; i != NumArgs; ++i)
1695      SubExprs[i+ARGS_START] = static_cast<Expr *>(ArgExprs[i]);
1696  }
1697  LBracloc = LBrac;
1698  RBracloc = RBrac;
1699}
1700
1701// constructor for class messages.
1702ObjCMessageExpr::ObjCMessageExpr(ObjCInterfaceDecl *cls, Selector selInfo,
1703                                 QualType retType, ObjCMethodDecl *mproto,
1704                                 SourceLocation LBrac, SourceLocation RBrac,
1705                                 Expr **ArgExprs, unsigned nargs)
1706: Expr(ObjCMessageExprClass, retType), SelName(selInfo),
1707MethodProto(mproto) {
1708  NumArgs = nargs;
1709  SubExprs = new Stmt*[NumArgs+1];
1710  SubExprs[RECEIVER] = (Expr*) ((uintptr_t) cls | IsClsMethDeclKnown);
1711  if (NumArgs) {
1712    for (unsigned i = 0; i != NumArgs; ++i)
1713      SubExprs[i+ARGS_START] = static_cast<Expr *>(ArgExprs[i]);
1714  }
1715  LBracloc = LBrac;
1716  RBracloc = RBrac;
1717}
1718
1719ObjCMessageExpr::ClassInfo ObjCMessageExpr::getClassInfo() const {
1720  uintptr_t x = (uintptr_t) SubExprs[RECEIVER];
1721  switch (x & Flags) {
1722    default:
1723      assert(false && "Invalid ObjCMessageExpr.");
1724    case IsInstMeth:
1725      return ClassInfo(0, 0);
1726    case IsClsMethDeclUnknown:
1727      return ClassInfo(0, (IdentifierInfo*) (x & ~Flags));
1728    case IsClsMethDeclKnown: {
1729      ObjCInterfaceDecl* D = (ObjCInterfaceDecl*) (x & ~Flags);
1730      return ClassInfo(D, D->getIdentifier());
1731    }
1732  }
1733}
1734
1735void ObjCMessageExpr::setClassInfo(const ObjCMessageExpr::ClassInfo &CI) {
1736  if (CI.first == 0 && CI.second == 0)
1737    SubExprs[RECEIVER] = (Expr*)((uintptr_t)0 | IsInstMeth);
1738  else if (CI.first == 0)
1739    SubExprs[RECEIVER] = (Expr*)((uintptr_t)CI.second | IsClsMethDeclUnknown);
1740  else
1741    SubExprs[RECEIVER] = (Expr*)((uintptr_t)CI.first | IsClsMethDeclKnown);
1742}
1743
1744
1745bool ChooseExpr::isConditionTrue(ASTContext &C) const {
1746  return getCond()->EvaluateAsInt(C) != 0;
1747}
1748
1749void ShuffleVectorExpr::setExprs(ASTContext &C, Expr ** Exprs,
1750                                 unsigned NumExprs) {
1751  if (SubExprs) C.Deallocate(SubExprs);
1752
1753  SubExprs = new (C) Stmt* [NumExprs];
1754  this->NumExprs = NumExprs;
1755  memcpy(SubExprs, Exprs, sizeof(Expr *) * NumExprs);
1756}
1757
1758void ShuffleVectorExpr::DoDestroy(ASTContext& C) {
1759  DestroyChildren(C);
1760  if (SubExprs) C.Deallocate(SubExprs);
1761  this->~ShuffleVectorExpr();
1762  C.Deallocate(this);
1763}
1764
1765void SizeOfAlignOfExpr::DoDestroy(ASTContext& C) {
1766  // Override default behavior of traversing children. If this has a type
1767  // operand and the type is a variable-length array, the child iteration
1768  // will iterate over the size expression. However, this expression belongs
1769  // to the type, not to this, so we don't want to delete it.
1770  // We still want to delete this expression.
1771  if (isArgumentType()) {
1772    this->~SizeOfAlignOfExpr();
1773    C.Deallocate(this);
1774  }
1775  else
1776    Expr::DoDestroy(C);
1777}
1778
1779//===----------------------------------------------------------------------===//
1780//  DesignatedInitExpr
1781//===----------------------------------------------------------------------===//
1782
1783IdentifierInfo *DesignatedInitExpr::Designator::getFieldName() {
1784  assert(Kind == FieldDesignator && "Only valid on a field designator");
1785  if (Field.NameOrField & 0x01)
1786    return reinterpret_cast<IdentifierInfo *>(Field.NameOrField&~0x01);
1787  else
1788    return getField()->getIdentifier();
1789}
1790
1791DesignatedInitExpr::DesignatedInitExpr(QualType Ty, unsigned NumDesignators,
1792                                       const Designator *Designators,
1793                                       SourceLocation EqualOrColonLoc,
1794                                       bool GNUSyntax,
1795                                       Expr **IndexExprs,
1796                                       unsigned NumIndexExprs,
1797                                       Expr *Init)
1798  : Expr(DesignatedInitExprClass, Ty,
1799         Init->isTypeDependent(), Init->isValueDependent()),
1800    EqualOrColonLoc(EqualOrColonLoc), GNUSyntax(GNUSyntax),
1801    NumDesignators(NumDesignators), NumSubExprs(NumIndexExprs + 1) {
1802  this->Designators = new Designator[NumDesignators];
1803
1804  // Record the initializer itself.
1805  child_iterator Child = child_begin();
1806  *Child++ = Init;
1807
1808  // Copy the designators and their subexpressions, computing
1809  // value-dependence along the way.
1810  unsigned IndexIdx = 0;
1811  for (unsigned I = 0; I != NumDesignators; ++I) {
1812    this->Designators[I] = Designators[I];
1813
1814    if (this->Designators[I].isArrayDesignator()) {
1815      // Compute type- and value-dependence.
1816      Expr *Index = IndexExprs[IndexIdx];
1817      ValueDependent = ValueDependent ||
1818        Index->isTypeDependent() || Index->isValueDependent();
1819
1820      // Copy the index expressions into permanent storage.
1821      *Child++ = IndexExprs[IndexIdx++];
1822    } else if (this->Designators[I].isArrayRangeDesignator()) {
1823      // Compute type- and value-dependence.
1824      Expr *Start = IndexExprs[IndexIdx];
1825      Expr *End = IndexExprs[IndexIdx + 1];
1826      ValueDependent = ValueDependent ||
1827        Start->isTypeDependent() || Start->isValueDependent() ||
1828        End->isTypeDependent() || End->isValueDependent();
1829
1830      // Copy the start/end expressions into permanent storage.
1831      *Child++ = IndexExprs[IndexIdx++];
1832      *Child++ = IndexExprs[IndexIdx++];
1833    }
1834  }
1835
1836  assert(IndexIdx == NumIndexExprs && "Wrong number of index expressions");
1837}
1838
1839DesignatedInitExpr *
1840DesignatedInitExpr::Create(ASTContext &C, Designator *Designators,
1841                           unsigned NumDesignators,
1842                           Expr **IndexExprs, unsigned NumIndexExprs,
1843                           SourceLocation ColonOrEqualLoc,
1844                           bool UsesColonSyntax, Expr *Init) {
1845  void *Mem = C.Allocate(sizeof(DesignatedInitExpr) +
1846                         sizeof(Stmt *) * (NumIndexExprs + 1), 8);
1847  return new (Mem) DesignatedInitExpr(C.VoidTy, NumDesignators, Designators,
1848                                      ColonOrEqualLoc, UsesColonSyntax,
1849                                      IndexExprs, NumIndexExprs, Init);
1850}
1851
1852DesignatedInitExpr *DesignatedInitExpr::CreateEmpty(ASTContext &C,
1853                                                    unsigned NumIndexExprs) {
1854  void *Mem = C.Allocate(sizeof(DesignatedInitExpr) +
1855                         sizeof(Stmt *) * (NumIndexExprs + 1), 8);
1856  return new (Mem) DesignatedInitExpr(NumIndexExprs + 1);
1857}
1858
1859void DesignatedInitExpr::setDesignators(const Designator *Desigs,
1860                                        unsigned NumDesigs) {
1861  if (Designators)
1862    delete [] Designators;
1863
1864  Designators = new Designator[NumDesigs];
1865  NumDesignators = NumDesigs;
1866  for (unsigned I = 0; I != NumDesigs; ++I)
1867    Designators[I] = Desigs[I];
1868}
1869
1870SourceRange DesignatedInitExpr::getSourceRange() const {
1871  SourceLocation StartLoc;
1872  Designator &First =
1873    *const_cast<DesignatedInitExpr*>(this)->designators_begin();
1874  if (First.isFieldDesignator()) {
1875    if (GNUSyntax)
1876      StartLoc = SourceLocation::getFromRawEncoding(First.Field.FieldLoc);
1877    else
1878      StartLoc = SourceLocation::getFromRawEncoding(First.Field.DotLoc);
1879  } else
1880    StartLoc =
1881      SourceLocation::getFromRawEncoding(First.ArrayOrRange.LBracketLoc);
1882  return SourceRange(StartLoc, getInit()->getSourceRange().getEnd());
1883}
1884
1885Expr *DesignatedInitExpr::getArrayIndex(const Designator& D) {
1886  assert(D.Kind == Designator::ArrayDesignator && "Requires array designator");
1887  char* Ptr = static_cast<char*>(static_cast<void *>(this));
1888  Ptr += sizeof(DesignatedInitExpr);
1889  Stmt **SubExprs = reinterpret_cast<Stmt**>(reinterpret_cast<void**>(Ptr));
1890  return cast<Expr>(*(SubExprs + D.ArrayOrRange.Index + 1));
1891}
1892
1893Expr *DesignatedInitExpr::getArrayRangeStart(const Designator& D) {
1894  assert(D.Kind == Designator::ArrayRangeDesignator &&
1895         "Requires array range designator");
1896  char* Ptr = static_cast<char*>(static_cast<void *>(this));
1897  Ptr += sizeof(DesignatedInitExpr);
1898  Stmt **SubExprs = reinterpret_cast<Stmt**>(reinterpret_cast<void**>(Ptr));
1899  return cast<Expr>(*(SubExprs + D.ArrayOrRange.Index + 1));
1900}
1901
1902Expr *DesignatedInitExpr::getArrayRangeEnd(const Designator& D) {
1903  assert(D.Kind == Designator::ArrayRangeDesignator &&
1904         "Requires array range designator");
1905  char* Ptr = static_cast<char*>(static_cast<void *>(this));
1906  Ptr += sizeof(DesignatedInitExpr);
1907  Stmt **SubExprs = reinterpret_cast<Stmt**>(reinterpret_cast<void**>(Ptr));
1908  return cast<Expr>(*(SubExprs + D.ArrayOrRange.Index + 2));
1909}
1910
1911/// \brief Replaces the designator at index @p Idx with the series
1912/// of designators in [First, Last).
1913void DesignatedInitExpr::ExpandDesignator(unsigned Idx,
1914                                          const Designator *First,
1915                                          const Designator *Last) {
1916  unsigned NumNewDesignators = Last - First;
1917  if (NumNewDesignators == 0) {
1918    std::copy_backward(Designators + Idx + 1,
1919                       Designators + NumDesignators,
1920                       Designators + Idx);
1921    --NumNewDesignators;
1922    return;
1923  } else if (NumNewDesignators == 1) {
1924    Designators[Idx] = *First;
1925    return;
1926  }
1927
1928  Designator *NewDesignators
1929    = new Designator[NumDesignators - 1 + NumNewDesignators];
1930  std::copy(Designators, Designators + Idx, NewDesignators);
1931  std::copy(First, Last, NewDesignators + Idx);
1932  std::copy(Designators + Idx + 1, Designators + NumDesignators,
1933            NewDesignators + Idx + NumNewDesignators);
1934  delete [] Designators;
1935  Designators = NewDesignators;
1936  NumDesignators = NumDesignators - 1 + NumNewDesignators;
1937}
1938
1939void DesignatedInitExpr::DoDestroy(ASTContext &C) {
1940  delete [] Designators;
1941  Expr::DoDestroy(C);
1942}
1943
1944ParenListExpr::ParenListExpr(ASTContext& C, SourceLocation lparenloc,
1945                             Expr **exprs, unsigned nexprs,
1946                             SourceLocation rparenloc)
1947: Expr(ParenListExprClass, QualType(),
1948       hasAnyTypeDependentArguments(exprs, nexprs),
1949       hasAnyValueDependentArguments(exprs, nexprs)),
1950  NumExprs(nexprs), LParenLoc(lparenloc), RParenLoc(rparenloc) {
1951
1952  Exprs = new (C) Stmt*[nexprs];
1953  for (unsigned i = 0; i != nexprs; ++i)
1954    Exprs[i] = exprs[i];
1955}
1956
1957void ParenListExpr::DoDestroy(ASTContext& C) {
1958  DestroyChildren(C);
1959  if (Exprs) C.Deallocate(Exprs);
1960  this->~ParenListExpr();
1961  C.Deallocate(this);
1962}
1963
1964//===----------------------------------------------------------------------===//
1965//  ExprIterator.
1966//===----------------------------------------------------------------------===//
1967
1968Expr* ExprIterator::operator[](size_t idx) { return cast<Expr>(I[idx]); }
1969Expr* ExprIterator::operator*() const { return cast<Expr>(*I); }
1970Expr* ExprIterator::operator->() const { return cast<Expr>(*I); }
1971const Expr* ConstExprIterator::operator[](size_t idx) const {
1972  return cast<Expr>(I[idx]);
1973}
1974const Expr* ConstExprIterator::operator*() const { return cast<Expr>(*I); }
1975const Expr* ConstExprIterator::operator->() const { return cast<Expr>(*I); }
1976
1977//===----------------------------------------------------------------------===//
1978//  Child Iterators for iterating over subexpressions/substatements
1979//===----------------------------------------------------------------------===//
1980
1981// DeclRefExpr
1982Stmt::child_iterator DeclRefExpr::child_begin() { return child_iterator(); }
1983Stmt::child_iterator DeclRefExpr::child_end() { return child_iterator(); }
1984
1985// ObjCIvarRefExpr
1986Stmt::child_iterator ObjCIvarRefExpr::child_begin() { return &Base; }
1987Stmt::child_iterator ObjCIvarRefExpr::child_end() { return &Base+1; }
1988
1989// ObjCPropertyRefExpr
1990Stmt::child_iterator ObjCPropertyRefExpr::child_begin() { return &Base; }
1991Stmt::child_iterator ObjCPropertyRefExpr::child_end() { return &Base+1; }
1992
1993// ObjCImplicitSetterGetterRefExpr
1994Stmt::child_iterator ObjCImplicitSetterGetterRefExpr::child_begin() {
1995  return &Base;
1996}
1997Stmt::child_iterator ObjCImplicitSetterGetterRefExpr::child_end() {
1998  return &Base+1;
1999}
2000
2001// ObjCSuperExpr
2002Stmt::child_iterator ObjCSuperExpr::child_begin() { return child_iterator(); }
2003Stmt::child_iterator ObjCSuperExpr::child_end() { return child_iterator(); }
2004
2005// ObjCIsaExpr
2006Stmt::child_iterator ObjCIsaExpr::child_begin() { return &Base; }
2007Stmt::child_iterator ObjCIsaExpr::child_end() { return &Base+1; }
2008
2009// PredefinedExpr
2010Stmt::child_iterator PredefinedExpr::child_begin() { return child_iterator(); }
2011Stmt::child_iterator PredefinedExpr::child_end() { return child_iterator(); }
2012
2013// IntegerLiteral
2014Stmt::child_iterator IntegerLiteral::child_begin() { return child_iterator(); }
2015Stmt::child_iterator IntegerLiteral::child_end() { return child_iterator(); }
2016
2017// CharacterLiteral
2018Stmt::child_iterator CharacterLiteral::child_begin() { return child_iterator();}
2019Stmt::child_iterator CharacterLiteral::child_end() { return child_iterator(); }
2020
2021// FloatingLiteral
2022Stmt::child_iterator FloatingLiteral::child_begin() { return child_iterator(); }
2023Stmt::child_iterator FloatingLiteral::child_end() { return child_iterator(); }
2024
2025// ImaginaryLiteral
2026Stmt::child_iterator ImaginaryLiteral::child_begin() { return &Val; }
2027Stmt::child_iterator ImaginaryLiteral::child_end() { return &Val+1; }
2028
2029// StringLiteral
2030Stmt::child_iterator StringLiteral::child_begin() { return child_iterator(); }
2031Stmt::child_iterator StringLiteral::child_end() { return child_iterator(); }
2032
2033// ParenExpr
2034Stmt::child_iterator ParenExpr::child_begin() { return &Val; }
2035Stmt::child_iterator ParenExpr::child_end() { return &Val+1; }
2036
2037// UnaryOperator
2038Stmt::child_iterator UnaryOperator::child_begin() { return &Val; }
2039Stmt::child_iterator UnaryOperator::child_end() { return &Val+1; }
2040
2041// SizeOfAlignOfExpr
2042Stmt::child_iterator SizeOfAlignOfExpr::child_begin() {
2043  // If this is of a type and the type is a VLA type (and not a typedef), the
2044  // size expression of the VLA needs to be treated as an executable expression.
2045  // Why isn't this weirdness documented better in StmtIterator?
2046  if (isArgumentType()) {
2047    if (VariableArrayType* T = dyn_cast<VariableArrayType>(
2048                                   getArgumentType().getTypePtr()))
2049      return child_iterator(T);
2050    return child_iterator();
2051  }
2052  return child_iterator(&Argument.Ex);
2053}
2054Stmt::child_iterator SizeOfAlignOfExpr::child_end() {
2055  if (isArgumentType())
2056    return child_iterator();
2057  return child_iterator(&Argument.Ex + 1);
2058}
2059
2060// ArraySubscriptExpr
2061Stmt::child_iterator ArraySubscriptExpr::child_begin() {
2062  return &SubExprs[0];
2063}
2064Stmt::child_iterator ArraySubscriptExpr::child_end() {
2065  return &SubExprs[0]+END_EXPR;
2066}
2067
2068// CallExpr
2069Stmt::child_iterator CallExpr::child_begin() {
2070  return &SubExprs[0];
2071}
2072Stmt::child_iterator CallExpr::child_end() {
2073  return &SubExprs[0]+NumArgs+ARGS_START;
2074}
2075
2076// MemberExpr
2077Stmt::child_iterator MemberExpr::child_begin() { return &Base; }
2078Stmt::child_iterator MemberExpr::child_end() { return &Base+1; }
2079
2080// ExtVectorElementExpr
2081Stmt::child_iterator ExtVectorElementExpr::child_begin() { return &Base; }
2082Stmt::child_iterator ExtVectorElementExpr::child_end() { return &Base+1; }
2083
2084// CompoundLiteralExpr
2085Stmt::child_iterator CompoundLiteralExpr::child_begin() { return &Init; }
2086Stmt::child_iterator CompoundLiteralExpr::child_end() { return &Init+1; }
2087
2088// CastExpr
2089Stmt::child_iterator CastExpr::child_begin() { return &Op; }
2090Stmt::child_iterator CastExpr::child_end() { return &Op+1; }
2091
2092// BinaryOperator
2093Stmt::child_iterator BinaryOperator::child_begin() {
2094  return &SubExprs[0];
2095}
2096Stmt::child_iterator BinaryOperator::child_end() {
2097  return &SubExprs[0]+END_EXPR;
2098}
2099
2100// ConditionalOperator
2101Stmt::child_iterator ConditionalOperator::child_begin() {
2102  return &SubExprs[0];
2103}
2104Stmt::child_iterator ConditionalOperator::child_end() {
2105  return &SubExprs[0]+END_EXPR;
2106}
2107
2108// AddrLabelExpr
2109Stmt::child_iterator AddrLabelExpr::child_begin() { return child_iterator(); }
2110Stmt::child_iterator AddrLabelExpr::child_end() { return child_iterator(); }
2111
2112// StmtExpr
2113Stmt::child_iterator StmtExpr::child_begin() { return &SubStmt; }
2114Stmt::child_iterator StmtExpr::child_end() { return &SubStmt+1; }
2115
2116// TypesCompatibleExpr
2117Stmt::child_iterator TypesCompatibleExpr::child_begin() {
2118  return child_iterator();
2119}
2120
2121Stmt::child_iterator TypesCompatibleExpr::child_end() {
2122  return child_iterator();
2123}
2124
2125// ChooseExpr
2126Stmt::child_iterator ChooseExpr::child_begin() { return &SubExprs[0]; }
2127Stmt::child_iterator ChooseExpr::child_end() { return &SubExprs[0]+END_EXPR; }
2128
2129// GNUNullExpr
2130Stmt::child_iterator GNUNullExpr::child_begin() { return child_iterator(); }
2131Stmt::child_iterator GNUNullExpr::child_end() { return child_iterator(); }
2132
2133// ShuffleVectorExpr
2134Stmt::child_iterator ShuffleVectorExpr::child_begin() {
2135  return &SubExprs[0];
2136}
2137Stmt::child_iterator ShuffleVectorExpr::child_end() {
2138  return &SubExprs[0]+NumExprs;
2139}
2140
2141// VAArgExpr
2142Stmt::child_iterator VAArgExpr::child_begin() { return &Val; }
2143Stmt::child_iterator VAArgExpr::child_end() { return &Val+1; }
2144
2145// InitListExpr
2146Stmt::child_iterator InitListExpr::child_begin() {
2147  return InitExprs.size() ? &InitExprs[0] : 0;
2148}
2149Stmt::child_iterator InitListExpr::child_end() {
2150  return InitExprs.size() ? &InitExprs[0] + InitExprs.size() : 0;
2151}
2152
2153// DesignatedInitExpr
2154Stmt::child_iterator DesignatedInitExpr::child_begin() {
2155  char* Ptr = static_cast<char*>(static_cast<void *>(this));
2156  Ptr += sizeof(DesignatedInitExpr);
2157  return reinterpret_cast<Stmt**>(reinterpret_cast<void**>(Ptr));
2158}
2159Stmt::child_iterator DesignatedInitExpr::child_end() {
2160  return child_iterator(&*child_begin() + NumSubExprs);
2161}
2162
2163// ImplicitValueInitExpr
2164Stmt::child_iterator ImplicitValueInitExpr::child_begin() {
2165  return child_iterator();
2166}
2167
2168Stmt::child_iterator ImplicitValueInitExpr::child_end() {
2169  return child_iterator();
2170}
2171
2172// ParenListExpr
2173Stmt::child_iterator ParenListExpr::child_begin() {
2174  return &Exprs[0];
2175}
2176Stmt::child_iterator ParenListExpr::child_end() {
2177  return &Exprs[0]+NumExprs;
2178}
2179
2180// ObjCStringLiteral
2181Stmt::child_iterator ObjCStringLiteral::child_begin() {
2182  return &String;
2183}
2184Stmt::child_iterator ObjCStringLiteral::child_end() {
2185  return &String+1;
2186}
2187
2188// ObjCEncodeExpr
2189Stmt::child_iterator ObjCEncodeExpr::child_begin() { return child_iterator(); }
2190Stmt::child_iterator ObjCEncodeExpr::child_end() { return child_iterator(); }
2191
2192// ObjCSelectorExpr
2193Stmt::child_iterator ObjCSelectorExpr::child_begin() {
2194  return child_iterator();
2195}
2196Stmt::child_iterator ObjCSelectorExpr::child_end() {
2197  return child_iterator();
2198}
2199
2200// ObjCProtocolExpr
2201Stmt::child_iterator ObjCProtocolExpr::child_begin() {
2202  return child_iterator();
2203}
2204Stmt::child_iterator ObjCProtocolExpr::child_end() {
2205  return child_iterator();
2206}
2207
2208// ObjCMessageExpr
2209Stmt::child_iterator ObjCMessageExpr::child_begin() {
2210  return getReceiver() ? &SubExprs[0] : &SubExprs[0] + ARGS_START;
2211}
2212Stmt::child_iterator ObjCMessageExpr::child_end() {
2213  return &SubExprs[0]+ARGS_START+getNumArgs();
2214}
2215
2216// Blocks
2217Stmt::child_iterator BlockExpr::child_begin() { return child_iterator(); }
2218Stmt::child_iterator BlockExpr::child_end() { return child_iterator(); }
2219
2220Stmt::child_iterator BlockDeclRefExpr::child_begin() { return child_iterator();}
2221Stmt::child_iterator BlockDeclRefExpr::child_end() { return child_iterator(); }
2222