Expr.cpp revision 9a979c327c442597c6a9cee961336530460fed04 
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/ExprObjC.h"
15#include "clang/AST/ASTContext.h"
16#include "clang/AST/APValue.h"
17#include "clang/AST/StmtVisitor.h"
18#include "clang/Basic/IdentifierTable.h"
19#include "clang/Basic/TargetInfo.h"
20using namespace clang;
21
22//===----------------------------------------------------------------------===//
23// Primary Expressions.
24//===----------------------------------------------------------------------===//
25
26/// getValueAsApproximateDouble - This returns the value as an inaccurate
27/// double.  Note that this may cause loss of precision, but is useful for
28/// debugging dumps, etc.
29double FloatingLiteral::getValueAsApproximateDouble() const {
30  llvm::APFloat V = getValue();
31  V.convert(llvm::APFloat::IEEEdouble, llvm::APFloat::rmNearestTiesToEven);
32  return V.convertToDouble();
33}
34
35
36StringLiteral::StringLiteral(const char *strData, unsigned byteLength,
37                             bool Wide, QualType t, SourceLocation firstLoc,
38                             SourceLocation lastLoc) :
39  Expr(StringLiteralClass, t) {
40  // OPTIMIZE: could allocate this appended to the StringLiteral.
41  char *AStrData = new char[byteLength];
42  memcpy(AStrData, strData, byteLength);
43  StrData = AStrData;
44  ByteLength = byteLength;
45  IsWide = Wide;
46  firstTokLoc = firstLoc;
47  lastTokLoc = lastLoc;
48}
49
50StringLiteral::~StringLiteral() {
51  delete[] StrData;
52}
53
54bool UnaryOperator::isPostfix(Opcode Op) {
55  switch (Op) {
56  case PostInc:
57  case PostDec:
58    return true;
59  default:
60    return false;
61  }
62}
63
64/// getOpcodeStr - Turn an Opcode enum value into the punctuation char it
65/// corresponds to, e.g. "sizeof" or "[pre]++".
66const char *UnaryOperator::getOpcodeStr(Opcode Op) {
67  switch (Op) {
68  default: assert(0 && "Unknown unary operator");
69  case PostInc: return "++";
70  case PostDec: return "--";
71  case PreInc:  return "++";
72  case PreDec:  return "--";
73  case AddrOf:  return "&";
74  case Deref:   return "*";
75  case Plus:    return "+";
76  case Minus:   return "-";
77  case Not:     return "~";
78  case LNot:    return "!";
79  case Real:    return "__real";
80  case Imag:    return "__imag";
81  case SizeOf:  return "sizeof";
82  case AlignOf: return "alignof";
83  case Extension: return "__extension__";
84  case OffsetOf: return "__builtin_offsetof";
85  }
86}
87
88//===----------------------------------------------------------------------===//
89// Postfix Operators.
90//===----------------------------------------------------------------------===//
91
92
93CallExpr::CallExpr(Expr *fn, Expr **args, unsigned numargs, QualType t,
94                   SourceLocation rparenloc)
95  : Expr(CallExprClass, t), NumArgs(numargs) {
96  SubExprs = new Stmt*[numargs+1];
97  SubExprs[FN] = fn;
98  for (unsigned i = 0; i != numargs; ++i)
99    SubExprs[i+ARGS_START] = args[i];
100  RParenLoc = rparenloc;
101}
102
103/// setNumArgs - This changes the number of arguments present in this call.
104/// Any orphaned expressions are deleted by this, and any new operands are set
105/// to null.
106void CallExpr::setNumArgs(unsigned NumArgs) {
107  // No change, just return.
108  if (NumArgs == getNumArgs()) return;
109
110  // If shrinking # arguments, just delete the extras and forgot them.
111  if (NumArgs < getNumArgs()) {
112    for (unsigned i = NumArgs, e = getNumArgs(); i != e; ++i)
113      delete getArg(i);
114    this->NumArgs = NumArgs;
115    return;
116  }
117
118  // Otherwise, we are growing the # arguments.  New an bigger argument array.
119  Stmt **NewSubExprs = new Stmt*[NumArgs+1];
120  // Copy over args.
121  for (unsigned i = 0; i != getNumArgs()+ARGS_START; ++i)
122    NewSubExprs[i] = SubExprs[i];
123  // Null out new args.
124  for (unsigned i = getNumArgs()+ARGS_START; i != NumArgs+ARGS_START; ++i)
125    NewSubExprs[i] = 0;
126
127  delete[] SubExprs;
128  SubExprs = NewSubExprs;
129  this->NumArgs = NumArgs;
130}
131
132bool CallExpr::isBuiltinConstantExpr() const {
133  // All simple function calls (e.g. func()) are implicitly cast to pointer to
134  // function. As a result, we try and obtain the DeclRefExpr from the
135  // ImplicitCastExpr.
136  const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(getCallee());
137  if (!ICE) // FIXME: deal with more complex calls (e.g. (func)(), (*func)()).
138    return false;
139
140  const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(ICE->getSubExpr());
141  if (!DRE)
142    return false;
143
144  const FunctionDecl *FDecl = dyn_cast<FunctionDecl>(DRE->getDecl());
145  if (!FDecl)
146    return false;
147
148  unsigned builtinID = FDecl->getIdentifier()->getBuiltinID();
149  if (!builtinID)
150    return false;
151
152  // We have a builtin that is a constant expression
153  return builtinID == Builtin::BI__builtin___CFStringMakeConstantString ||
154         builtinID == Builtin::BI__builtin_classify_type;
155}
156
157bool CallExpr::isBuiltinClassifyType(llvm::APSInt &Result) const {
158  // The following enum mimics gcc's internal "typeclass.h" file.
159  enum gcc_type_class {
160    no_type_class = -1,
161    void_type_class, integer_type_class, char_type_class,
162    enumeral_type_class, boolean_type_class,
163    pointer_type_class, reference_type_class, offset_type_class,
164    real_type_class, complex_type_class,
165    function_type_class, method_type_class,
166    record_type_class, union_type_class,
167    array_type_class, string_type_class,
168    lang_type_class
169  };
170  Result.setIsSigned(true);
171
172  // All simple function calls (e.g. func()) are implicitly cast to pointer to
173  // function. As a result, we try and obtain the DeclRefExpr from the
174  // ImplicitCastExpr.
175  const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(getCallee());
176  if (!ICE) // FIXME: deal with more complex calls (e.g. (func)(), (*func)()).
177    return false;
178  const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(ICE->getSubExpr());
179  if (!DRE)
180    return false;
181
182  // We have a DeclRefExpr.
183  if (strcmp(DRE->getDecl()->getName(), "__builtin_classify_type") == 0) {
184    // If no argument was supplied, default to "no_type_class". This isn't
185    // ideal, however it's what gcc does.
186    Result = static_cast<uint64_t>(no_type_class);
187    if (NumArgs >= 1) {
188      QualType argType = getArg(0)->getType();
189
190      if (argType->isVoidType())
191        Result = void_type_class;
192      else if (argType->isEnumeralType())
193        Result = enumeral_type_class;
194      else if (argType->isBooleanType())
195        Result = boolean_type_class;
196      else if (argType->isCharType())
197        Result = string_type_class; // gcc doesn't appear to use char_type_class
198      else if (argType->isIntegerType())
199        Result = integer_type_class;
200      else if (argType->isPointerType())
201        Result = pointer_type_class;
202      else if (argType->isReferenceType())
203        Result = reference_type_class;
204      else if (argType->isRealType())
205        Result = real_type_class;
206      else if (argType->isComplexType())
207        Result = complex_type_class;
208      else if (argType->isFunctionType())
209        Result = function_type_class;
210      else if (argType->isStructureType())
211        Result = record_type_class;
212      else if (argType->isUnionType())
213        Result = union_type_class;
214      else if (argType->isArrayType())
215        Result = array_type_class;
216      else if (argType->isUnionType())
217        Result = union_type_class;
218      else  // FIXME: offset_type_class, method_type_class, & lang_type_class?
219        assert(0 && "CallExpr::isBuiltinClassifyType(): unimplemented type");
220    }
221    return true;
222  }
223  return false;
224}
225
226/// getOpcodeStr - Turn an Opcode enum value into the punctuation char it
227/// corresponds to, e.g. "<<=".
228const char *BinaryOperator::getOpcodeStr(Opcode Op) {
229  switch (Op) {
230  default: assert(0 && "Unknown binary operator");
231  case Mul:       return "*";
232  case Div:       return "/";
233  case Rem:       return "%";
234  case Add:       return "+";
235  case Sub:       return "-";
236  case Shl:       return "<<";
237  case Shr:       return ">>";
238  case LT:        return "<";
239  case GT:        return ">";
240  case LE:        return "<=";
241  case GE:        return ">=";
242  case EQ:        return "==";
243  case NE:        return "!=";
244  case And:       return "&";
245  case Xor:       return "^";
246  case Or:        return "|";
247  case LAnd:      return "&&";
248  case LOr:       return "||";
249  case Assign:    return "=";
250  case MulAssign: return "*=";
251  case DivAssign: return "/=";
252  case RemAssign: return "%=";
253  case AddAssign: return "+=";
254  case SubAssign: return "-=";
255  case ShlAssign: return "<<=";
256  case ShrAssign: return ">>=";
257  case AndAssign: return "&=";
258  case XorAssign: return "^=";
259  case OrAssign:  return "|=";
260  case Comma:     return ",";
261  }
262}
263
264InitListExpr::InitListExpr(SourceLocation lbraceloc,
265                           Expr **initexprs, unsigned numinits,
266                           SourceLocation rbraceloc)
267  : Expr(InitListExprClass, QualType()),
268    LBraceLoc(lbraceloc), RBraceLoc(rbraceloc)
269{
270  for (unsigned i = 0; i != numinits; i++)
271    InitExprs.push_back(initexprs[i]);
272}
273
274//===----------------------------------------------------------------------===//
275// Generic Expression Routines
276//===----------------------------------------------------------------------===//
277
278/// hasLocalSideEffect - Return true if this immediate expression has side
279/// effects, not counting any sub-expressions.
280bool Expr::hasLocalSideEffect() const {
281  switch (getStmtClass()) {
282  default:
283    return false;
284  case ParenExprClass:
285    return cast<ParenExpr>(this)->getSubExpr()->hasLocalSideEffect();
286  case UnaryOperatorClass: {
287    const UnaryOperator *UO = cast<UnaryOperator>(this);
288
289    switch (UO->getOpcode()) {
290    default: return false;
291    case UnaryOperator::PostInc:
292    case UnaryOperator::PostDec:
293    case UnaryOperator::PreInc:
294    case UnaryOperator::PreDec:
295      return true;                     // ++/--
296
297    case UnaryOperator::Deref:
298      // Dereferencing a volatile pointer is a side-effect.
299      return getType().isVolatileQualified();
300    case UnaryOperator::Real:
301    case UnaryOperator::Imag:
302      // accessing a piece of a volatile complex is a side-effect.
303      return UO->getSubExpr()->getType().isVolatileQualified();
304
305    case UnaryOperator::Extension:
306      return UO->getSubExpr()->hasLocalSideEffect();
307    }
308  }
309  case BinaryOperatorClass: {
310    const BinaryOperator *BinOp = cast<BinaryOperator>(this);
311    // Consider comma to have side effects if the LHS and RHS both do.
312    if (BinOp->getOpcode() == BinaryOperator::Comma)
313      return BinOp->getLHS()->hasLocalSideEffect() &&
314             BinOp->getRHS()->hasLocalSideEffect();
315
316    return BinOp->isAssignmentOp();
317  }
318  case CompoundAssignOperatorClass:
319    return true;
320
321  case ConditionalOperatorClass: {
322    const ConditionalOperator *Exp = cast<ConditionalOperator>(this);
323    return Exp->getCond()->hasLocalSideEffect()
324           || (Exp->getLHS() && Exp->getLHS()->hasLocalSideEffect())
325           || (Exp->getRHS() && Exp->getRHS()->hasLocalSideEffect());
326  }
327
328  case MemberExprClass:
329  case ArraySubscriptExprClass:
330    // If the base pointer or element is to a volatile pointer/field, accessing
331    // if is a side effect.
332    return getType().isVolatileQualified();
333
334  case CallExprClass:
335    // TODO: check attributes for pure/const.   "void foo() { strlen("bar"); }"
336    // should warn.
337    return true;
338  case ObjCMessageExprClass:
339    return true;
340  case StmtExprClass:
341    // TODO: check the inside of the statement expression
342    return true;
343
344  case CastExprClass:
345    // If this is a cast to void, check the operand.  Otherwise, the result of
346    // the cast is unused.
347    if (getType()->isVoidType())
348      return cast<CastExpr>(this)->getSubExpr()->hasLocalSideEffect();
349    return false;
350
351  case ImplicitCastExprClass:
352    // Check the operand, since implicit casts are inserted by Sema
353    return cast<ImplicitCastExpr>(this)->getSubExpr()->hasLocalSideEffect();
354
355  case CXXDefaultArgExprClass:
356    return cast<CXXDefaultArgExpr>(this)->getExpr()->hasLocalSideEffect();
357  }
358}
359
360/// isLvalue - C99 6.3.2.1: an lvalue is an expression with an object type or an
361/// incomplete type other than void. Nonarray expressions that can be lvalues:
362///  - name, where name must be a variable
363///  - e[i]
364///  - (e), where e must be an lvalue
365///  - e.name, where e must be an lvalue
366///  - e->name
367///  - *e, the type of e cannot be a function type
368///  - string-constant
369///  - (__real__ e) and (__imag__ e) where e is an lvalue  [GNU extension]
370///  - reference type [C++ [expr]]
371///
372Expr::isLvalueResult Expr::isLvalue() const {
373  // first, check the type (C99 6.3.2.1)
374  if (TR->isFunctionType()) // from isObjectType()
375    return LV_NotObjectType;
376
377  // Allow qualified void which is an incomplete type other than void (yuck).
378  if (TR->isVoidType() && !TR.getCanonicalType().getCVRQualifiers())
379    return LV_IncompleteVoidType;
380
381  if (TR->isReferenceType()) // C++ [expr]
382    return LV_Valid;
383
384  // the type looks fine, now check the expression
385  switch (getStmtClass()) {
386  case StringLiteralClass: // C99 6.5.1p4
387    return LV_Valid;
388  case ArraySubscriptExprClass: // C99 6.5.3p4 (e1[e2] == (*((e1)+(e2))))
389    // For vectors, make sure base is an lvalue (i.e. not a function call).
390    if (cast<ArraySubscriptExpr>(this)->getBase()->getType()->isVectorType())
391      return cast<ArraySubscriptExpr>(this)->getBase()->isLvalue();
392    return LV_Valid;
393  case DeclRefExprClass: { // C99 6.5.1p2
394    const Decl *RefdDecl = cast<DeclRefExpr>(this)->getDecl();
395    if (isa<VarDecl>(RefdDecl) || isa<ImplicitParamDecl>(RefdDecl))
396      return LV_Valid;
397    break;
398  }
399  case MemberExprClass: { // C99 6.5.2.3p4
400    const MemberExpr *m = cast<MemberExpr>(this);
401    return m->isArrow() ? LV_Valid : m->getBase()->isLvalue();
402  }
403  case UnaryOperatorClass:
404    if (cast<UnaryOperator>(this)->getOpcode() == UnaryOperator::Deref)
405      return LV_Valid; // C99 6.5.3p4
406
407    if (cast<UnaryOperator>(this)->getOpcode() == UnaryOperator::Real ||
408        cast<UnaryOperator>(this)->getOpcode() == UnaryOperator::Imag)
409      return cast<UnaryOperator>(this)->getSubExpr()->isLvalue();  // GNU.
410    break;
411  case ParenExprClass: // C99 6.5.1p5
412    return cast<ParenExpr>(this)->getSubExpr()->isLvalue();
413  case CompoundLiteralExprClass: // C99 6.5.2.5p5
414    return LV_Valid;
415  case ExtVectorElementExprClass:
416    if (cast<ExtVectorElementExpr>(this)->containsDuplicateElements())
417      return LV_DuplicateVectorComponents;
418    return LV_Valid;
419  case ObjCIvarRefExprClass: // ObjC instance variables are lvalues.
420    return LV_Valid;
421  case ObjCPropertyRefExprClass: // FIXME: check if read-only property.
422    return LV_Valid;
423  case PreDefinedExprClass:
424    return (cast<PreDefinedExpr>(this)->getIdentType() == PreDefinedExpr::CXXThis
425            ? LV_InvalidExpression
426            : LV_Valid);
427  case CXXDefaultArgExprClass:
428    return cast<CXXDefaultArgExpr>(this)->getExpr()->isLvalue();
429  default:
430    break;
431  }
432  return LV_InvalidExpression;
433}
434
435/// isModifiableLvalue - C99 6.3.2.1: an lvalue that does not have array type,
436/// does not have an incomplete type, does not have a const-qualified type, and
437/// if it is a structure or union, does not have any member (including,
438/// recursively, any member or element of all contained aggregates or unions)
439/// with a const-qualified type.
440Expr::isModifiableLvalueResult Expr::isModifiableLvalue() const {
441  isLvalueResult lvalResult = isLvalue();
442
443  switch (lvalResult) {
444  case LV_Valid: break;
445  case LV_NotObjectType: return MLV_NotObjectType;
446  case LV_IncompleteVoidType: return MLV_IncompleteVoidType;
447  case LV_DuplicateVectorComponents: return MLV_DuplicateVectorComponents;
448  case LV_InvalidExpression: return MLV_InvalidExpression;
449  }
450  if (TR.isConstQualified())
451    return MLV_ConstQualified;
452  if (TR->isArrayType())
453    return MLV_ArrayType;
454  if (TR->isIncompleteType())
455    return MLV_IncompleteType;
456
457  if (const RecordType *r = dyn_cast<RecordType>(TR.getCanonicalType())) {
458    if (r->hasConstFields())
459      return MLV_ConstQualified;
460  }
461  return MLV_Valid;
462}
463
464/// hasGlobalStorage - Return true if this expression has static storage
465/// duration.  This means that the address of this expression is a link-time
466/// constant.
467bool Expr::hasGlobalStorage() const {
468  switch (getStmtClass()) {
469  default:
470    return false;
471  case ParenExprClass:
472    return cast<ParenExpr>(this)->getSubExpr()->hasGlobalStorage();
473  case ImplicitCastExprClass:
474    return cast<ImplicitCastExpr>(this)->getSubExpr()->hasGlobalStorage();
475  case CompoundLiteralExprClass:
476    return cast<CompoundLiteralExpr>(this)->isFileScope();
477  case DeclRefExprClass: {
478    const Decl *D = cast<DeclRefExpr>(this)->getDecl();
479    if (const VarDecl *VD = dyn_cast<VarDecl>(D))
480      return VD->hasGlobalStorage();
481    if (isa<FunctionDecl>(D))
482      return true;
483    return false;
484  }
485  case MemberExprClass: {
486    const MemberExpr *M = cast<MemberExpr>(this);
487    return !M->isArrow() && M->getBase()->hasGlobalStorage();
488  }
489  case ArraySubscriptExprClass:
490    return cast<ArraySubscriptExpr>(this)->getBase()->hasGlobalStorage();
491  case PreDefinedExprClass:
492    return true;
493  case CXXDefaultArgExprClass:
494    return cast<CXXDefaultArgExpr>(this)->getExpr()->hasGlobalStorage();
495  }
496}
497
498Expr* Expr::IgnoreParens() {
499  Expr* E = this;
500  while (ParenExpr* P = dyn_cast<ParenExpr>(E))
501    E = P->getSubExpr();
502
503  return E;
504}
505
506/// IgnoreParenCasts - Ignore parentheses and casts.  Strip off any ParenExpr
507/// or CastExprs or ImplicitCastExprs, returning their operand.
508Expr *Expr::IgnoreParenCasts() {
509  Expr *E = this;
510  while (true) {
511    if (ParenExpr *P = dyn_cast<ParenExpr>(E))
512      E = P->getSubExpr();
513    else if (CastExpr *P = dyn_cast<CastExpr>(E))
514      E = P->getSubExpr();
515    else if (ImplicitCastExpr *P = dyn_cast<ImplicitCastExpr>(E))
516      E = P->getSubExpr();
517    else
518      return E;
519  }
520}
521
522
523bool Expr::isConstantExpr(ASTContext &Ctx, SourceLocation *Loc) const {
524  switch (getStmtClass()) {
525  default:
526    if (Loc) *Loc = getLocStart();
527    return false;
528  case ParenExprClass:
529    return cast<ParenExpr>(this)->getSubExpr()->isConstantExpr(Ctx, Loc);
530  case StringLiteralClass:
531  case ObjCStringLiteralClass:
532  case FloatingLiteralClass:
533  case IntegerLiteralClass:
534  case CharacterLiteralClass:
535  case ImaginaryLiteralClass:
536  case TypesCompatibleExprClass:
537  case CXXBoolLiteralExprClass:
538    return true;
539  case CallExprClass: {
540    const CallExpr *CE = cast<CallExpr>(this);
541    if (CE->isBuiltinConstantExpr())
542      return true;
543    if (Loc) *Loc = getLocStart();
544    return false;
545  }
546  case DeclRefExprClass: {
547    const Decl *D = cast<DeclRefExpr>(this)->getDecl();
548    // Accept address of function.
549    if (isa<EnumConstantDecl>(D) || isa<FunctionDecl>(D))
550      return true;
551    if (Loc) *Loc = getLocStart();
552    if (isa<VarDecl>(D))
553      return TR->isArrayType();
554    return false;
555  }
556  case CompoundLiteralExprClass:
557    if (Loc) *Loc = getLocStart();
558    // Allow "(int []){2,4}", since the array will be converted to a pointer.
559    // Allow "(vector type){2,4}" since the elements are all constant.
560    return TR->isArrayType() || TR->isVectorType();
561  case UnaryOperatorClass: {
562    const UnaryOperator *Exp = cast<UnaryOperator>(this);
563
564    // C99 6.6p9
565    if (Exp->getOpcode() == UnaryOperator::AddrOf) {
566      if (!Exp->getSubExpr()->hasGlobalStorage()) {
567        if (Loc) *Loc = getLocStart();
568        return false;
569      }
570      return true;
571    }
572
573    // Get the operand value.  If this is sizeof/alignof, do not evalute the
574    // operand.  This affects C99 6.6p3.
575    if (!Exp->isSizeOfAlignOfOp() &&
576        Exp->getOpcode() != UnaryOperator::OffsetOf &&
577        !Exp->getSubExpr()->isConstantExpr(Ctx, Loc))
578      return false;
579
580    switch (Exp->getOpcode()) {
581    // Address, indirect, pre/post inc/dec, etc are not valid constant exprs.
582    // See C99 6.6p3.
583    default:
584      if (Loc) *Loc = Exp->getOperatorLoc();
585      return false;
586    case UnaryOperator::Extension:
587      return true;  // FIXME: this is wrong.
588    case UnaryOperator::SizeOf:
589    case UnaryOperator::AlignOf:
590    case UnaryOperator::OffsetOf:
591      // sizeof(vla) is not a constantexpr: C99 6.5.3.4p2.
592      if (!Exp->getSubExpr()->getType()->isConstantSizeType()) {
593        if (Loc) *Loc = Exp->getOperatorLoc();
594        return false;
595      }
596      return true;
597    case UnaryOperator::LNot:
598    case UnaryOperator::Plus:
599    case UnaryOperator::Minus:
600    case UnaryOperator::Not:
601      return true;
602    }
603  }
604  case SizeOfAlignOfTypeExprClass: {
605    const SizeOfAlignOfTypeExpr *Exp = cast<SizeOfAlignOfTypeExpr>(this);
606    // alignof always evaluates to a constant.
607    if (Exp->isSizeOf() && !Exp->getArgumentType()->isVoidType() &&
608        !Exp->getArgumentType()->isConstantSizeType()) {
609      if (Loc) *Loc = Exp->getOperatorLoc();
610      return false;
611    }
612    return true;
613  }
614  case BinaryOperatorClass: {
615    const BinaryOperator *Exp = cast<BinaryOperator>(this);
616
617    // The LHS of a constant expr is always evaluated and needed.
618    if (!Exp->getLHS()->isConstantExpr(Ctx, Loc))
619      return false;
620
621    if (!Exp->getRHS()->isConstantExpr(Ctx, Loc))
622      return false;
623    return true;
624  }
625  case ImplicitCastExprClass:
626  case CastExprClass: {
627    const Expr *SubExpr;
628    SourceLocation CastLoc;
629    if (const CastExpr *C = dyn_cast<CastExpr>(this)) {
630      SubExpr = C->getSubExpr();
631      CastLoc = C->getLParenLoc();
632    } else {
633      SubExpr = cast<ImplicitCastExpr>(this)->getSubExpr();
634      CastLoc = getLocStart();
635    }
636    if (!SubExpr->isConstantExpr(Ctx, Loc)) {
637      if (Loc) *Loc = SubExpr->getLocStart();
638      return false;
639    }
640    return true;
641  }
642  case ConditionalOperatorClass: {
643    const ConditionalOperator *Exp = cast<ConditionalOperator>(this);
644    if (!Exp->getCond()->isConstantExpr(Ctx, Loc) ||
645        // Handle the GNU extension for missing LHS.
646        !(Exp->getLHS() && Exp->getLHS()->isConstantExpr(Ctx, Loc)) ||
647        !Exp->getRHS()->isConstantExpr(Ctx, Loc))
648      return false;
649    return true;
650  }
651  case InitListExprClass: {
652    const InitListExpr *Exp = cast<InitListExpr>(this);
653    unsigned numInits = Exp->getNumInits();
654    for (unsigned i = 0; i < numInits; i++) {
655      if (!Exp->getInit(i)->isConstantExpr(Ctx, Loc)) {
656        if (Loc) *Loc = Exp->getInit(i)->getLocStart();
657        return false;
658      }
659    }
660    return true;
661  }
662  case CXXDefaultArgExprClass:
663    return cast<CXXDefaultArgExpr>(this)->getExpr()->isConstantExpr(Ctx, Loc);
664  }
665}
666
667/// isIntegerConstantExpr - this recursive routine will test if an expression is
668/// an integer constant expression. Note: With the introduction of VLA's in
669/// C99 the result of the sizeof operator is no longer always a constant
670/// expression. The generalization of the wording to include any subexpression
671/// that is not evaluated (C99 6.6p3) means that nonconstant subexpressions
672/// can appear as operands to other operators (e.g. &&, ||, ?:). For instance,
673/// "1 || f()" can be treated as a constant expression. In C90 this expression,
674/// occurring in a context requiring a constant, would have been a constraint
675/// violation. FIXME: This routine currently implements C90 semantics.
676/// To properly implement C99 semantics this routine will need to evaluate
677/// expressions involving operators previously mentioned.
678
679/// FIXME: Pass up a reason why! Invalid operation in i-c-e, division by zero,
680/// comma, etc
681///
682/// FIXME: This should ext-warn on overflow during evaluation!  ISO C does not
683/// permit this.  This includes things like (int)1e1000
684///
685/// FIXME: Handle offsetof.  Two things to do:  Handle GCC's __builtin_offsetof
686/// to support gcc 4.0+  and handle the idiom GCC recognizes with a null pointer
687/// cast+dereference.
688bool Expr::isIntegerConstantExpr(llvm::APSInt &Result, ASTContext &Ctx,
689                                 SourceLocation *Loc, bool isEvaluated) const {
690  switch (getStmtClass()) {
691  default:
692    if (Loc) *Loc = getLocStart();
693    return false;
694  case ParenExprClass:
695    return cast<ParenExpr>(this)->getSubExpr()->
696                     isIntegerConstantExpr(Result, Ctx, Loc, isEvaluated);
697  case IntegerLiteralClass:
698    Result = cast<IntegerLiteral>(this)->getValue();
699    break;
700  case CharacterLiteralClass: {
701    const CharacterLiteral *CL = cast<CharacterLiteral>(this);
702    Result.zextOrTrunc(static_cast<uint32_t>(Ctx.getTypeSize(getType())));
703    Result = CL->getValue();
704    Result.setIsUnsigned(!getType()->isSignedIntegerType());
705    break;
706  }
707  case TypesCompatibleExprClass: {
708    const TypesCompatibleExpr *TCE = cast<TypesCompatibleExpr>(this);
709    Result.zextOrTrunc(static_cast<uint32_t>(Ctx.getTypeSize(getType())));
710    Result = Ctx.typesAreCompatible(TCE->getArgType1(), TCE->getArgType2());
711    break;
712  }
713  case CallExprClass: {
714    const CallExpr *CE = cast<CallExpr>(this);
715    Result.zextOrTrunc(static_cast<uint32_t>(Ctx.getTypeSize(getType())));
716    if (CE->isBuiltinClassifyType(Result))
717      break;
718    if (Loc) *Loc = getLocStart();
719    return false;
720  }
721  case DeclRefExprClass:
722    if (const EnumConstantDecl *D =
723          dyn_cast<EnumConstantDecl>(cast<DeclRefExpr>(this)->getDecl())) {
724      Result = D->getInitVal();
725      break;
726    }
727    if (Loc) *Loc = getLocStart();
728    return false;
729  case UnaryOperatorClass: {
730    const UnaryOperator *Exp = cast<UnaryOperator>(this);
731
732    // Get the operand value.  If this is sizeof/alignof, do not evalute the
733    // operand.  This affects C99 6.6p3.
734    if (!Exp->isSizeOfAlignOfOp() && !Exp->isOffsetOfOp() &&
735        !Exp->getSubExpr()->isIntegerConstantExpr(Result, Ctx, Loc,isEvaluated))
736      return false;
737
738    switch (Exp->getOpcode()) {
739    // Address, indirect, pre/post inc/dec, etc are not valid constant exprs.
740    // See C99 6.6p3.
741    default:
742      if (Loc) *Loc = Exp->getOperatorLoc();
743      return false;
744    case UnaryOperator::Extension:
745      return true;  // FIXME: this is wrong.
746    case UnaryOperator::SizeOf:
747    case UnaryOperator::AlignOf:
748      // Return the result in the right width.
749      Result.zextOrTrunc(static_cast<uint32_t>(Ctx.getTypeSize(getType())));
750
751      // sizeof(void) and __alignof__(void) = 1 as a gcc extension.
752      if (Exp->getSubExpr()->getType()->isVoidType()) {
753        Result = 1;
754        break;
755      }
756
757      // sizeof(vla) is not a constantexpr: C99 6.5.3.4p2.
758      if (!Exp->getSubExpr()->getType()->isConstantSizeType()) {
759        if (Loc) *Loc = Exp->getOperatorLoc();
760        return false;
761      }
762
763      // Get information about the size or align.
764      if (Exp->getSubExpr()->getType()->isFunctionType()) {
765        // GCC extension: sizeof(function) = 1.
766        Result = Exp->getOpcode() == UnaryOperator::AlignOf ? 4 : 1;
767      } else {
768        unsigned CharSize = Ctx.Target.getCharWidth();
769        if (Exp->getOpcode() == UnaryOperator::AlignOf)
770          Result = Ctx.getTypeAlign(Exp->getSubExpr()->getType()) / CharSize;
771        else
772          Result = Ctx.getTypeSize(Exp->getSubExpr()->getType()) / CharSize;
773      }
774      break;
775    case UnaryOperator::LNot: {
776      bool Val = Result == 0;
777      Result.zextOrTrunc(static_cast<uint32_t>(Ctx.getTypeSize(getType())));
778      Result = Val;
779      break;
780    }
781    case UnaryOperator::Plus:
782      break;
783    case UnaryOperator::Minus:
784      Result = -Result;
785      break;
786    case UnaryOperator::Not:
787      Result = ~Result;
788      break;
789    case UnaryOperator::OffsetOf:
790      Result = Exp->evaluateOffsetOf(Ctx);
791    }
792    break;
793  }
794  case SizeOfAlignOfTypeExprClass: {
795    const SizeOfAlignOfTypeExpr *Exp = cast<SizeOfAlignOfTypeExpr>(this);
796
797    // Return the result in the right width.
798    Result.zextOrTrunc(static_cast<uint32_t>(Ctx.getTypeSize(getType())));
799
800    // sizeof(void) and __alignof__(void) = 1 as a gcc extension.
801    if (Exp->getArgumentType()->isVoidType()) {
802      Result = 1;
803      break;
804    }
805
806    // alignof always evaluates to a constant, sizeof does if arg is not VLA.
807    if (Exp->isSizeOf() && !Exp->getArgumentType()->isConstantSizeType()) {
808      if (Loc) *Loc = Exp->getOperatorLoc();
809      return false;
810    }
811
812    // Get information about the size or align.
813    if (Exp->getArgumentType()->isFunctionType()) {
814      // GCC extension: sizeof(function) = 1.
815      Result = Exp->isSizeOf() ? 1 : 4;
816    } else {
817      unsigned CharSize = Ctx.Target.getCharWidth();
818      if (Exp->isSizeOf())
819        Result = Ctx.getTypeSize(Exp->getArgumentType()) / CharSize;
820      else
821        Result = Ctx.getTypeAlign(Exp->getArgumentType()) / CharSize;
822    }
823    break;
824  }
825  case BinaryOperatorClass: {
826    const BinaryOperator *Exp = cast<BinaryOperator>(this);
827
828    // The LHS of a constant expr is always evaluated and needed.
829    if (!Exp->getLHS()->isIntegerConstantExpr(Result, Ctx, Loc, isEvaluated))
830      return false;
831
832    llvm::APSInt RHS(Result);
833
834    // The short-circuiting &&/|| operators don't necessarily evaluate their
835    // RHS.  Make sure to pass isEvaluated down correctly.
836    if (Exp->isLogicalOp()) {
837      bool RHSEval;
838      if (Exp->getOpcode() == BinaryOperator::LAnd)
839        RHSEval = Result != 0;
840      else {
841        assert(Exp->getOpcode() == BinaryOperator::LOr &&"Unexpected logical");
842        RHSEval = Result == 0;
843      }
844
845      if (!Exp->getRHS()->isIntegerConstantExpr(RHS, Ctx, Loc,
846                                                isEvaluated & RHSEval))
847        return false;
848    } else {
849      if (!Exp->getRHS()->isIntegerConstantExpr(RHS, Ctx, Loc, isEvaluated))
850        return false;
851    }
852
853    switch (Exp->getOpcode()) {
854    default:
855      if (Loc) *Loc = getLocStart();
856      return false;
857    case BinaryOperator::Mul:
858      Result *= RHS;
859      break;
860    case BinaryOperator::Div:
861      if (RHS == 0) {
862        if (!isEvaluated) break;
863        if (Loc) *Loc = getLocStart();
864        return false;
865      }
866      Result /= RHS;
867      break;
868    case BinaryOperator::Rem:
869      if (RHS == 0) {
870        if (!isEvaluated) break;
871        if (Loc) *Loc = getLocStart();
872        return false;
873      }
874      Result %= RHS;
875      break;
876    case BinaryOperator::Add: Result += RHS; break;
877    case BinaryOperator::Sub: Result -= RHS; break;
878    case BinaryOperator::Shl:
879      Result <<=
880        static_cast<uint32_t>(RHS.getLimitedValue(Result.getBitWidth()-1));
881      break;
882    case BinaryOperator::Shr:
883      Result >>=
884        static_cast<uint32_t>(RHS.getLimitedValue(Result.getBitWidth()-1));
885      break;
886    case BinaryOperator::LT:  Result = Result < RHS; break;
887    case BinaryOperator::GT:  Result = Result > RHS; break;
888    case BinaryOperator::LE:  Result = Result <= RHS; break;
889    case BinaryOperator::GE:  Result = Result >= RHS; break;
890    case BinaryOperator::EQ:  Result = Result == RHS; break;
891    case BinaryOperator::NE:  Result = Result != RHS; break;
892    case BinaryOperator::And: Result &= RHS; break;
893    case BinaryOperator::Xor: Result ^= RHS; break;
894    case BinaryOperator::Or:  Result |= RHS; break;
895    case BinaryOperator::LAnd:
896      Result = Result != 0 && RHS != 0;
897      break;
898    case BinaryOperator::LOr:
899      Result = Result != 0 || RHS != 0;
900      break;
901
902    case BinaryOperator::Comma:
903      // C99 6.6p3: "shall not contain assignment, ..., or comma operators,
904      // *except* when they are contained within a subexpression that is not
905      // evaluated".  Note that Assignment can never happen due to constraints
906      // on the LHS subexpr, so we don't need to check it here.
907      if (isEvaluated) {
908        if (Loc) *Loc = getLocStart();
909        return false;
910      }
911
912      // The result of the constant expr is the RHS.
913      Result = RHS;
914      return true;
915    }
916
917    assert(!Exp->isAssignmentOp() && "LHS can't be a constant expr!");
918    break;
919  }
920  case ImplicitCastExprClass:
921  case CastExprClass: {
922    const Expr *SubExpr;
923    SourceLocation CastLoc;
924    if (const CastExpr *C = dyn_cast<CastExpr>(this)) {
925      SubExpr = C->getSubExpr();
926      CastLoc = C->getLParenLoc();
927    } else {
928      SubExpr = cast<ImplicitCastExpr>(this)->getSubExpr();
929      CastLoc = getLocStart();
930    }
931
932    // C99 6.6p6: shall only convert arithmetic types to integer types.
933    if (!SubExpr->getType()->isArithmeticType() ||
934        !getType()->isIntegerType()) {
935      if (Loc) *Loc = SubExpr->getLocStart();
936      // GCC accepts pointers as an extension.
937      // FIXME: check getLangOptions().NoExtensions. At the moment, it doesn't
938      // appear possible to get langOptions() from the Expr.
939      if (SubExpr->getType()->isPointerType()) // && !NoExtensions
940        return true;
941      return false;
942    }
943
944    uint32_t DestWidth = static_cast<uint32_t>(Ctx.getTypeSize(getType()));
945
946    // Handle simple integer->integer casts.
947    if (SubExpr->getType()->isIntegerType()) {
948      if (!SubExpr->isIntegerConstantExpr(Result, Ctx, Loc, isEvaluated))
949        return false;
950
951      // Figure out if this is a truncate, extend or noop cast.
952      // If the input is signed, do a sign extend, noop, or truncate.
953      if (getType()->isBooleanType()) {
954        // Conversion to bool compares against zero.
955        Result = Result != 0;
956        Result.zextOrTrunc(DestWidth);
957      } else if (SubExpr->getType()->isSignedIntegerType())
958        Result.sextOrTrunc(DestWidth);
959      else  // If the input is unsigned, do a zero extend, noop, or truncate.
960        Result.zextOrTrunc(DestWidth);
961      break;
962    }
963
964    // Allow floating constants that are the immediate operands of casts or that
965    // are parenthesized.
966    const Expr *Operand = SubExpr;
967    while (const ParenExpr *PE = dyn_cast<ParenExpr>(Operand))
968      Operand = PE->getSubExpr();
969
970    // If this isn't a floating literal, we can't handle it.
971    const FloatingLiteral *FL = dyn_cast<FloatingLiteral>(Operand);
972    if (!FL) {
973      if (Loc) *Loc = Operand->getLocStart();
974      return false;
975    }
976
977    // If the destination is boolean, compare against zero.
978    if (getType()->isBooleanType()) {
979      Result = !FL->getValue().isZero();
980      Result.zextOrTrunc(DestWidth);
981      break;
982    }
983
984    // Determine whether we are converting to unsigned or signed.
985    bool DestSigned = getType()->isSignedIntegerType();
986
987    // TODO: Warn on overflow, but probably not here: isIntegerConstantExpr can
988    // be called multiple times per AST.
989    uint64_t Space[4];
990    (void)FL->getValue().convertToInteger(Space, DestWidth, DestSigned,
991                                          llvm::APFloat::rmTowardZero);
992    Result = llvm::APInt(DestWidth, 4, Space);
993    break;
994  }
995  case ConditionalOperatorClass: {
996    const ConditionalOperator *Exp = cast<ConditionalOperator>(this);
997
998    if (!Exp->getCond()->isIntegerConstantExpr(Result, Ctx, Loc, isEvaluated))
999      return false;
1000
1001    const Expr *TrueExp  = Exp->getLHS();
1002    const Expr *FalseExp = Exp->getRHS();
1003    if (Result == 0) std::swap(TrueExp, FalseExp);
1004
1005    // Evaluate the false one first, discard the result.
1006    if (FalseExp && !FalseExp->isIntegerConstantExpr(Result, Ctx, Loc, false))
1007      return false;
1008    // Evalute the true one, capture the result.
1009    if (TrueExp &&
1010        !TrueExp->isIntegerConstantExpr(Result, Ctx, Loc, isEvaluated))
1011      return false;
1012    break;
1013  }
1014  case CXXDefaultArgExprClass:
1015    return cast<CXXDefaultArgExpr>(this)
1016             ->isIntegerConstantExpr(Result, Ctx, Loc, isEvaluated);
1017  }
1018
1019  // Cases that are valid constant exprs fall through to here.
1020  Result.setIsUnsigned(getType()->isUnsignedIntegerType());
1021  return true;
1022}
1023
1024/// isNullPointerConstant - C99 6.3.2.3p3 -  Return true if this is either an
1025/// integer constant expression with the value zero, or if this is one that is
1026/// cast to void*.
1027bool Expr::isNullPointerConstant(ASTContext &Ctx) const {
1028  // Strip off a cast to void*, if it exists.
1029  if (const CastExpr *CE = dyn_cast<CastExpr>(this)) {
1030    // Check that it is a cast to void*.
1031    if (const PointerType *PT = CE->getType()->getAsPointerType()) {
1032      QualType Pointee = PT->getPointeeType();
1033      if (Pointee.getCVRQualifiers() == 0 &&
1034          Pointee->isVoidType() &&                                 // to void*
1035          CE->getSubExpr()->getType()->isIntegerType())            // from int.
1036        return CE->getSubExpr()->isNullPointerConstant(Ctx);
1037    }
1038  } else if (const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(this)) {
1039    // Ignore the ImplicitCastExpr type entirely.
1040    return ICE->getSubExpr()->isNullPointerConstant(Ctx);
1041  } else if (const ParenExpr *PE = dyn_cast<ParenExpr>(this)) {
1042    // Accept ((void*)0) as a null pointer constant, as many other
1043    // implementations do.
1044    return PE->getSubExpr()->isNullPointerConstant(Ctx);
1045  } else if (const CXXDefaultArgExpr *DefaultArg
1046               = dyn_cast<CXXDefaultArgExpr>(this)) {
1047    // See through default argument expressions
1048    return DefaultArg->getExpr()->isNullPointerConstant(Ctx);
1049  }
1050
1051  // This expression must be an integer type.
1052  if (!getType()->isIntegerType())
1053    return false;
1054
1055  // If we have an integer constant expression, we need to *evaluate* it and
1056  // test for the value 0.
1057  llvm::APSInt Val(32);
1058  return isIntegerConstantExpr(Val, Ctx, 0, true) && Val == 0;
1059}
1060
1061unsigned ExtVectorElementExpr::getNumElements() const {
1062  if (const VectorType *VT = getType()->getAsVectorType())
1063    return VT->getNumElements();
1064  return 1;
1065}
1066
1067/// containsDuplicateElements - Return true if any element access is repeated.
1068bool ExtVectorElementExpr::containsDuplicateElements() const {
1069  const char *compStr = Accessor.getName();
1070  unsigned length = strlen(compStr);
1071
1072  for (unsigned i = 0; i < length-1; i++) {
1073    const char *s = compStr+i;
1074    for (const char c = *s++; *s; s++)
1075      if (c == *s)
1076        return true;
1077  }
1078  return false;
1079}
1080
1081/// getEncodedElementAccess - We encode the fields as a llvm ConstantArray.
1082void ExtVectorElementExpr::getEncodedElementAccess(
1083                                  llvm::SmallVectorImpl<unsigned> &Elts) const {
1084  const char *compStr = Accessor.getName();
1085
1086  bool isHi =   !strcmp(compStr, "hi");
1087  bool isLo =   !strcmp(compStr, "lo");
1088  bool isEven = !strcmp(compStr, "e");
1089  bool isOdd  = !strcmp(compStr, "o");
1090
1091  for (unsigned i = 0, e = getNumElements(); i != e; ++i) {
1092    uint64_t Index;
1093
1094    if (isHi)
1095      Index = e + i;
1096    else if (isLo)
1097      Index = i;
1098    else if (isEven)
1099      Index = 2 * i;
1100    else if (isOdd)
1101      Index = 2 * i + 1;
1102    else
1103      Index = ExtVectorType::getAccessorIdx(compStr[i]);
1104
1105    Elts.push_back(Index);
1106  }
1107}
1108
1109// constructor for instance messages.
1110ObjCMessageExpr::ObjCMessageExpr(Expr *receiver, Selector selInfo,
1111                QualType retType, ObjCMethodDecl *mproto,
1112                SourceLocation LBrac, SourceLocation RBrac,
1113                Expr **ArgExprs, unsigned nargs)
1114  : Expr(ObjCMessageExprClass, retType), SelName(selInfo),
1115    MethodProto(mproto) {
1116  NumArgs = nargs;
1117  SubExprs = new Stmt*[NumArgs+1];
1118  SubExprs[RECEIVER] = receiver;
1119  if (NumArgs) {
1120    for (unsigned i = 0; i != NumArgs; ++i)
1121      SubExprs[i+ARGS_START] = static_cast<Expr *>(ArgExprs[i]);
1122  }
1123  LBracloc = LBrac;
1124  RBracloc = RBrac;
1125}
1126
1127// constructor for class messages.
1128// FIXME: clsName should be typed to ObjCInterfaceType
1129ObjCMessageExpr::ObjCMessageExpr(IdentifierInfo *clsName, Selector selInfo,
1130                QualType retType, ObjCMethodDecl *mproto,
1131                SourceLocation LBrac, SourceLocation RBrac,
1132                Expr **ArgExprs, unsigned nargs)
1133  : Expr(ObjCMessageExprClass, retType), SelName(selInfo),
1134    MethodProto(mproto) {
1135  NumArgs = nargs;
1136  SubExprs = new Stmt*[NumArgs+1];
1137  SubExprs[RECEIVER] = (Expr*) ((uintptr_t) clsName | IsClsMethDeclUnknown);
1138  if (NumArgs) {
1139    for (unsigned i = 0; i != NumArgs; ++i)
1140      SubExprs[i+ARGS_START] = static_cast<Expr *>(ArgExprs[i]);
1141  }
1142  LBracloc = LBrac;
1143  RBracloc = RBrac;
1144}
1145
1146// constructor for class messages.
1147ObjCMessageExpr::ObjCMessageExpr(ObjCInterfaceDecl *cls, Selector selInfo,
1148                                 QualType retType, ObjCMethodDecl *mproto,
1149                                 SourceLocation LBrac, SourceLocation RBrac,
1150                                 Expr **ArgExprs, unsigned nargs)
1151: Expr(ObjCMessageExprClass, retType), SelName(selInfo),
1152MethodProto(mproto) {
1153  NumArgs = nargs;
1154  SubExprs = new Stmt*[NumArgs+1];
1155  SubExprs[RECEIVER] = (Expr*) ((uintptr_t) cls | IsClsMethDeclKnown);
1156  if (NumArgs) {
1157    for (unsigned i = 0; i != NumArgs; ++i)
1158      SubExprs[i+ARGS_START] = static_cast<Expr *>(ArgExprs[i]);
1159  }
1160  LBracloc = LBrac;
1161  RBracloc = RBrac;
1162}
1163
1164ObjCMessageExpr::ClassInfo ObjCMessageExpr::getClassInfo() const {
1165  uintptr_t x = (uintptr_t) SubExprs[RECEIVER];
1166  switch (x & Flags) {
1167    default:
1168      assert(false && "Invalid ObjCMessageExpr.");
1169    case IsInstMeth:
1170      return ClassInfo(0, 0);
1171    case IsClsMethDeclUnknown:
1172      return ClassInfo(0, (IdentifierInfo*) (x & ~Flags));
1173    case IsClsMethDeclKnown: {
1174      ObjCInterfaceDecl* D = (ObjCInterfaceDecl*) (x & ~Flags);
1175      return ClassInfo(D, D->getIdentifier());
1176    }
1177  }
1178}
1179
1180bool ChooseExpr::isConditionTrue(ASTContext &C) const {
1181  llvm::APSInt CondVal(32);
1182  bool IsConst = getCond()->isIntegerConstantExpr(CondVal, C);
1183  assert(IsConst && "Condition of choose expr must be i-c-e"); IsConst=IsConst;
1184  return CondVal != 0;
1185}
1186
1187static int64_t evaluateOffsetOf(ASTContext& C, const Expr *E)
1188{
1189  if (const MemberExpr *ME = dyn_cast<MemberExpr>(E)) {
1190    QualType Ty = ME->getBase()->getType();
1191
1192    RecordDecl *RD = Ty->getAsRecordType()->getDecl();
1193    const ASTRecordLayout &RL = C.getASTRecordLayout(RD);
1194    FieldDecl *FD = ME->getMemberDecl();
1195
1196    // FIXME: This is linear time.
1197    unsigned i = 0, e = 0;
1198    for (i = 0, e = RD->getNumMembers(); i != e; i++) {
1199      if (RD->getMember(i) == FD)
1200        break;
1201    }
1202
1203    return RL.getFieldOffset(i) + evaluateOffsetOf(C, ME->getBase());
1204  } else if (const ArraySubscriptExpr *ASE = dyn_cast<ArraySubscriptExpr>(E)) {
1205    const Expr *Base = ASE->getBase();
1206    llvm::APSInt Idx(32);
1207    bool ICE = ASE->getIdx()->isIntegerConstantExpr(Idx, C);
1208    assert(ICE && "Array index is not a constant integer!");
1209
1210    int64_t size = C.getTypeSize(ASE->getType());
1211    size *= Idx.getSExtValue();
1212
1213    return size + evaluateOffsetOf(C, Base);
1214  } else if (isa<CompoundLiteralExpr>(E))
1215    return 0;
1216
1217  assert(0 && "Unknown offsetof subexpression!");
1218  return 0;
1219}
1220
1221int64_t UnaryOperator::evaluateOffsetOf(ASTContext& C) const
1222{
1223  assert(Opc == OffsetOf && "Unary operator not offsetof!");
1224
1225  unsigned CharSize = C.Target.getCharWidth();
1226  return ::evaluateOffsetOf(C, cast<Expr>(Val)) / CharSize;
1227}
1228
1229//===----------------------------------------------------------------------===//
1230//  Child Iterators for iterating over subexpressions/substatements
1231//===----------------------------------------------------------------------===//
1232
1233// DeclRefExpr
1234Stmt::child_iterator DeclRefExpr::child_begin() { return child_iterator(); }
1235Stmt::child_iterator DeclRefExpr::child_end() { return child_iterator(); }
1236
1237// ObjCIvarRefExpr
1238Stmt::child_iterator ObjCIvarRefExpr::child_begin() { return &Base; }
1239Stmt::child_iterator ObjCIvarRefExpr::child_end() { return &Base+1; }
1240
1241// ObjCPropertyRefExpr
1242Stmt::child_iterator ObjCPropertyRefExpr::child_begin() { return &Base; }
1243Stmt::child_iterator ObjCPropertyRefExpr::child_end() { return &Base+1; }
1244
1245// ObjCSuperRefExpr
1246Stmt::child_iterator ObjCSuperRefExpr::child_begin() { return child_iterator();}
1247Stmt::child_iterator ObjCSuperRefExpr::child_end() { return child_iterator(); }
1248
1249// PreDefinedExpr
1250Stmt::child_iterator PreDefinedExpr::child_begin() { return child_iterator(); }
1251Stmt::child_iterator PreDefinedExpr::child_end() { return child_iterator(); }
1252
1253// IntegerLiteral
1254Stmt::child_iterator IntegerLiteral::child_begin() { return child_iterator(); }
1255Stmt::child_iterator IntegerLiteral::child_end() { return child_iterator(); }
1256
1257// CharacterLiteral
1258Stmt::child_iterator CharacterLiteral::child_begin() { return child_iterator(); }
1259Stmt::child_iterator CharacterLiteral::child_end() { return child_iterator(); }
1260
1261// FloatingLiteral
1262Stmt::child_iterator FloatingLiteral::child_begin() { return child_iterator(); }
1263Stmt::child_iterator FloatingLiteral::child_end() { return child_iterator(); }
1264
1265// ImaginaryLiteral
1266Stmt::child_iterator ImaginaryLiteral::child_begin() { return &Val; }
1267Stmt::child_iterator ImaginaryLiteral::child_end() { return &Val+1; }
1268
1269// StringLiteral
1270Stmt::child_iterator StringLiteral::child_begin() { return child_iterator(); }
1271Stmt::child_iterator StringLiteral::child_end() { return child_iterator(); }
1272
1273// ParenExpr
1274Stmt::child_iterator ParenExpr::child_begin() { return &Val; }
1275Stmt::child_iterator ParenExpr::child_end() { return &Val+1; }
1276
1277// UnaryOperator
1278Stmt::child_iterator UnaryOperator::child_begin() { return &Val; }
1279Stmt::child_iterator UnaryOperator::child_end() { return &Val+1; }
1280
1281// SizeOfAlignOfTypeExpr
1282Stmt::child_iterator SizeOfAlignOfTypeExpr::child_begin() {
1283  // If the type is a VLA type (and not a typedef), the size expression of the
1284  // VLA needs to be treated as an executable expression.
1285  if (VariableArrayType* T = dyn_cast<VariableArrayType>(Ty.getTypePtr()))
1286    return child_iterator(T);
1287  else
1288    return child_iterator();
1289}
1290Stmt::child_iterator SizeOfAlignOfTypeExpr::child_end() {
1291  return child_iterator();
1292}
1293
1294// ArraySubscriptExpr
1295Stmt::child_iterator ArraySubscriptExpr::child_begin() {
1296  return &SubExprs[0];
1297}
1298Stmt::child_iterator ArraySubscriptExpr::child_end() {
1299  return &SubExprs[0]+END_EXPR;
1300}
1301
1302// CallExpr
1303Stmt::child_iterator CallExpr::child_begin() {
1304  return &SubExprs[0];
1305}
1306Stmt::child_iterator CallExpr::child_end() {
1307  return &SubExprs[0]+NumArgs+ARGS_START;
1308}
1309
1310// MemberExpr
1311Stmt::child_iterator MemberExpr::child_begin() { return &Base; }
1312Stmt::child_iterator MemberExpr::child_end() { return &Base+1; }
1313
1314// ExtVectorElementExpr
1315Stmt::child_iterator ExtVectorElementExpr::child_begin() { return &Base; }
1316Stmt::child_iterator ExtVectorElementExpr::child_end() { return &Base+1; }
1317
1318// CompoundLiteralExpr
1319Stmt::child_iterator CompoundLiteralExpr::child_begin() { return &Init; }
1320Stmt::child_iterator CompoundLiteralExpr::child_end() { return &Init+1; }
1321
1322// ImplicitCastExpr
1323Stmt::child_iterator ImplicitCastExpr::child_begin() { return &Op; }
1324Stmt::child_iterator ImplicitCastExpr::child_end() { return &Op+1; }
1325
1326// CastExpr
1327Stmt::child_iterator CastExpr::child_begin() { return &Op; }
1328Stmt::child_iterator CastExpr::child_end() { return &Op+1; }
1329
1330// BinaryOperator
1331Stmt::child_iterator BinaryOperator::child_begin() {
1332  return &SubExprs[0];
1333}
1334Stmt::child_iterator BinaryOperator::child_end() {
1335  return &SubExprs[0]+END_EXPR;
1336}
1337
1338// ConditionalOperator
1339Stmt::child_iterator ConditionalOperator::child_begin() {
1340  return &SubExprs[0];
1341}
1342Stmt::child_iterator ConditionalOperator::child_end() {
1343  return &SubExprs[0]+END_EXPR;
1344}
1345
1346// AddrLabelExpr
1347Stmt::child_iterator AddrLabelExpr::child_begin() { return child_iterator(); }
1348Stmt::child_iterator AddrLabelExpr::child_end() { return child_iterator(); }
1349
1350// StmtExpr
1351Stmt::child_iterator StmtExpr::child_begin() { return &SubStmt; }
1352Stmt::child_iterator StmtExpr::child_end() { return &SubStmt+1; }
1353
1354// TypesCompatibleExpr
1355Stmt::child_iterator TypesCompatibleExpr::child_begin() {
1356  return child_iterator();
1357}
1358
1359Stmt::child_iterator TypesCompatibleExpr::child_end() {
1360  return child_iterator();
1361}
1362
1363// ChooseExpr
1364Stmt::child_iterator ChooseExpr::child_begin() { return &SubExprs[0]; }
1365Stmt::child_iterator ChooseExpr::child_end() { return &SubExprs[0]+END_EXPR; }
1366
1367// OverloadExpr
1368Stmt::child_iterator OverloadExpr::child_begin() { return &SubExprs[0]; }
1369Stmt::child_iterator OverloadExpr::child_end() { return &SubExprs[0]+NumExprs; }
1370
1371// ShuffleVectorExpr
1372Stmt::child_iterator ShuffleVectorExpr::child_begin() {
1373  return &SubExprs[0];
1374}
1375Stmt::child_iterator ShuffleVectorExpr::child_end() {
1376  return &SubExprs[0]+NumExprs;
1377}
1378
1379// VAArgExpr
1380Stmt::child_iterator VAArgExpr::child_begin() { return &Val; }
1381Stmt::child_iterator VAArgExpr::child_end() { return &Val+1; }
1382
1383// InitListExpr
1384Stmt::child_iterator InitListExpr::child_begin() {
1385  return InitExprs.size() ? &InitExprs[0] : 0;
1386}
1387Stmt::child_iterator InitListExpr::child_end() {
1388  return InitExprs.size() ? &InitExprs[0] + InitExprs.size() : 0;
1389}
1390
1391// ObjCStringLiteral
1392Stmt::child_iterator ObjCStringLiteral::child_begin() {
1393  return child_iterator();
1394}
1395Stmt::child_iterator ObjCStringLiteral::child_end() {
1396  return child_iterator();
1397}
1398
1399// ObjCEncodeExpr
1400Stmt::child_iterator ObjCEncodeExpr::child_begin() { return child_iterator(); }
1401Stmt::child_iterator ObjCEncodeExpr::child_end() { return child_iterator(); }
1402
1403// ObjCSelectorExpr
1404Stmt::child_iterator ObjCSelectorExpr::child_begin() {
1405  return child_iterator();
1406}
1407Stmt::child_iterator ObjCSelectorExpr::child_end() {
1408  return child_iterator();
1409}
1410
1411// ObjCProtocolExpr
1412Stmt::child_iterator ObjCProtocolExpr::child_begin() {
1413  return child_iterator();
1414}
1415Stmt::child_iterator ObjCProtocolExpr::child_end() {
1416  return child_iterator();
1417}
1418
1419// ObjCMessageExpr
1420Stmt::child_iterator ObjCMessageExpr::child_begin() {
1421  return getReceiver() ? &SubExprs[0] : &SubExprs[0] + ARGS_START;
1422}
1423Stmt::child_iterator ObjCMessageExpr::child_end() {
1424  return &SubExprs[0]+ARGS_START+getNumArgs();
1425}
1426
1427