Expr.cpp revision 213541a68a3e137d11d2cefb612c6cdb410d7e8e 
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/ASTContext.h"
16#include "clang/AST/StmtVisitor.h"
17#include "clang/Basic/IdentifierTable.h"
18#include "clang/Basic/TargetInfo.h"
19using namespace clang;
20
21//===----------------------------------------------------------------------===//
22// Primary Expressions.
23//===----------------------------------------------------------------------===//
24
25StringLiteral::StringLiteral(const char *strData, unsigned byteLength,
26                             bool Wide, QualType t, SourceLocation firstLoc,
27                             SourceLocation lastLoc) :
28  Expr(StringLiteralClass, t) {
29  // OPTIMIZE: could allocate this appended to the StringLiteral.
30  char *AStrData = new char[byteLength];
31  memcpy(AStrData, strData, byteLength);
32  StrData = AStrData;
33  ByteLength = byteLength;
34  IsWide = Wide;
35  firstTokLoc = firstLoc;
36  lastTokLoc = lastLoc;
37}
38
39StringLiteral::~StringLiteral() {
40  delete[] StrData;
41}
42
43bool UnaryOperator::isPostfix(Opcode Op) {
44  switch (Op) {
45  case PostInc:
46  case PostDec:
47    return true;
48  default:
49    return false;
50  }
51}
52
53/// getOpcodeStr - Turn an Opcode enum value into the punctuation char it
54/// corresponds to, e.g. "sizeof" or "[pre]++".
55const char *UnaryOperator::getOpcodeStr(Opcode Op) {
56  switch (Op) {
57  default: assert(0 && "Unknown unary operator");
58  case PostInc: return "++";
59  case PostDec: return "--";
60  case PreInc:  return "++";
61  case PreDec:  return "--";
62  case AddrOf:  return "&";
63  case Deref:   return "*";
64  case Plus:    return "+";
65  case Minus:   return "-";
66  case Not:     return "~";
67  case LNot:    return "!";
68  case Real:    return "__real";
69  case Imag:    return "__imag";
70  case SizeOf:  return "sizeof";
71  case AlignOf: return "alignof";
72  case Extension: return "__extension__";
73  case OffsetOf: return "__builtin_offsetof";
74  }
75}
76
77//===----------------------------------------------------------------------===//
78// Postfix Operators.
79//===----------------------------------------------------------------------===//
80
81
82CallExpr::CallExpr(Expr *fn, Expr **args, unsigned numargs, QualType t,
83                   SourceLocation rparenloc)
84  : Expr(CallExprClass, t), NumArgs(numargs) {
85  SubExprs = new Expr*[numargs+1];
86  SubExprs[FN] = fn;
87  for (unsigned i = 0; i != numargs; ++i)
88    SubExprs[i+ARGS_START] = args[i];
89  RParenLoc = rparenloc;
90}
91
92/// setNumArgs - This changes the number of arguments present in this call.
93/// Any orphaned expressions are deleted by this, and any new operands are set
94/// to null.
95void CallExpr::setNumArgs(unsigned NumArgs) {
96  // No change, just return.
97  if (NumArgs == getNumArgs()) return;
98
99  // If shrinking # arguments, just delete the extras and forgot them.
100  if (NumArgs < getNumArgs()) {
101    for (unsigned i = NumArgs, e = getNumArgs(); i != e; ++i)
102      delete getArg(i);
103    this->NumArgs = NumArgs;
104    return;
105  }
106
107  // Otherwise, we are growing the # arguments.  New an bigger argument array.
108  Expr **NewSubExprs = new Expr*[NumArgs+1];
109  // Copy over args.
110  for (unsigned i = 0; i != getNumArgs()+ARGS_START; ++i)
111    NewSubExprs[i] = SubExprs[i];
112  // Null out new args.
113  for (unsigned i = getNumArgs()+ARGS_START; i != NumArgs+ARGS_START; ++i)
114    NewSubExprs[i] = 0;
115
116  delete[] SubExprs;
117  SubExprs = NewSubExprs;
118  this->NumArgs = NumArgs;
119}
120
121bool CallExpr::isBuiltinConstantExpr() const {
122  // All simple function calls (e.g. func()) are implicitly cast to pointer to
123  // function. As a result, we try and obtain the DeclRefExpr from the
124  // ImplicitCastExpr.
125  const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(getCallee());
126  if (!ICE) // FIXME: deal with more complex calls (e.g. (func)(), (*func)()).
127    return false;
128
129  const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(ICE->getSubExpr());
130  if (!DRE)
131    return false;
132
133  const FunctionDecl *FDecl = dyn_cast<FunctionDecl>(DRE->getDecl());
134  if (!FDecl)
135    return false;
136
137  unsigned builtinID = FDecl->getIdentifier()->getBuiltinID();
138  if (!builtinID)
139    return false;
140
141  // We have a builtin that is a constant expression
142  if (builtinID == Builtin::BI__builtin___CFStringMakeConstantString)
143    return true;
144  return false;
145}
146
147bool CallExpr::isBuiltinClassifyType(llvm::APSInt &Result) const {
148  // The following enum mimics gcc's internal "typeclass.h" file.
149  enum gcc_type_class {
150    no_type_class = -1,
151    void_type_class, integer_type_class, char_type_class,
152    enumeral_type_class, boolean_type_class,
153    pointer_type_class, reference_type_class, offset_type_class,
154    real_type_class, complex_type_class,
155    function_type_class, method_type_class,
156    record_type_class, union_type_class,
157    array_type_class, string_type_class,
158    lang_type_class
159  };
160  Result.setIsSigned(true);
161
162  // All simple function calls (e.g. func()) are implicitly cast to pointer to
163  // function. As a result, we try and obtain the DeclRefExpr from the
164  // ImplicitCastExpr.
165  const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(getCallee());
166  if (!ICE) // FIXME: deal with more complex calls (e.g. (func)(), (*func)()).
167    return false;
168  const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(ICE->getSubExpr());
169  if (!DRE)
170    return false;
171
172  // We have a DeclRefExpr.
173  if (strcmp(DRE->getDecl()->getName(), "__builtin_classify_type") == 0) {
174    // If no argument was supplied, default to "no_type_class". This isn't
175    // ideal, however it's what gcc does.
176    Result = static_cast<uint64_t>(no_type_class);
177    if (NumArgs >= 1) {
178      QualType argType = getArg(0)->getType();
179
180      if (argType->isVoidType())
181        Result = void_type_class;
182      else if (argType->isEnumeralType())
183        Result = enumeral_type_class;
184      else if (argType->isBooleanType())
185        Result = boolean_type_class;
186      else if (argType->isCharType())
187        Result = string_type_class; // gcc doesn't appear to use char_type_class
188      else if (argType->isIntegerType())
189        Result = integer_type_class;
190      else if (argType->isPointerType())
191        Result = pointer_type_class;
192      else if (argType->isReferenceType())
193        Result = reference_type_class;
194      else if (argType->isRealType())
195        Result = real_type_class;
196      else if (argType->isComplexType())
197        Result = complex_type_class;
198      else if (argType->isFunctionType())
199        Result = function_type_class;
200      else if (argType->isStructureType())
201        Result = record_type_class;
202      else if (argType->isUnionType())
203        Result = union_type_class;
204      else if (argType->isArrayType())
205        Result = array_type_class;
206      else if (argType->isUnionType())
207        Result = union_type_class;
208      else  // FIXME: offset_type_class, method_type_class, & lang_type_class?
209        assert(0 && "CallExpr::isBuiltinClassifyType(): unimplemented type");
210    }
211    return true;
212  }
213  return false;
214}
215
216/// getOpcodeStr - Turn an Opcode enum value into the punctuation char it
217/// corresponds to, e.g. "<<=".
218const char *BinaryOperator::getOpcodeStr(Opcode Op) {
219  switch (Op) {
220  default: assert(0 && "Unknown binary operator");
221  case Mul:       return "*";
222  case Div:       return "/";
223  case Rem:       return "%";
224  case Add:       return "+";
225  case Sub:       return "-";
226  case Shl:       return "<<";
227  case Shr:       return ">>";
228  case LT:        return "<";
229  case GT:        return ">";
230  case LE:        return "<=";
231  case GE:        return ">=";
232  case EQ:        return "==";
233  case NE:        return "!=";
234  case And:       return "&";
235  case Xor:       return "^";
236  case Or:        return "|";
237  case LAnd:      return "&&";
238  case LOr:       return "||";
239  case Assign:    return "=";
240  case MulAssign: return "*=";
241  case DivAssign: return "/=";
242  case RemAssign: return "%=";
243  case AddAssign: return "+=";
244  case SubAssign: return "-=";
245  case ShlAssign: return "<<=";
246  case ShrAssign: return ">>=";
247  case AndAssign: return "&=";
248  case XorAssign: return "^=";
249  case OrAssign:  return "|=";
250  case Comma:     return ",";
251  }
252}
253
254InitListExpr::InitListExpr(SourceLocation lbraceloc,
255                           Expr **initexprs, unsigned numinits,
256                           SourceLocation rbraceloc)
257  : Expr(InitListExprClass, QualType())
258  , NumInits(numinits)
259  , LBraceLoc(lbraceloc)
260  , RBraceLoc(rbraceloc)
261{
262  InitExprs = new Expr*[numinits];
263  for (unsigned i = 0; i != numinits; i++)
264    InitExprs[i] = initexprs[i];
265}
266
267//===----------------------------------------------------------------------===//
268// Generic Expression Routines
269//===----------------------------------------------------------------------===//
270
271/// hasLocalSideEffect - Return true if this immediate expression has side
272/// effects, not counting any sub-expressions.
273bool Expr::hasLocalSideEffect() const {
274  switch (getStmtClass()) {
275  default:
276    return false;
277  case ParenExprClass:
278    return cast<ParenExpr>(this)->getSubExpr()->hasLocalSideEffect();
279  case UnaryOperatorClass: {
280    const UnaryOperator *UO = cast<UnaryOperator>(this);
281
282    switch (UO->getOpcode()) {
283    default: return false;
284    case UnaryOperator::PostInc:
285    case UnaryOperator::PostDec:
286    case UnaryOperator::PreInc:
287    case UnaryOperator::PreDec:
288      return true;                     // ++/--
289
290    case UnaryOperator::Deref:
291      // Dereferencing a volatile pointer is a side-effect.
292      return getType().isVolatileQualified();
293    case UnaryOperator::Real:
294    case UnaryOperator::Imag:
295      // accessing a piece of a volatile complex is a side-effect.
296      return UO->getSubExpr()->getType().isVolatileQualified();
297
298    case UnaryOperator::Extension:
299      return UO->getSubExpr()->hasLocalSideEffect();
300    }
301  }
302  case BinaryOperatorClass: {
303    const BinaryOperator *BinOp = cast<BinaryOperator>(this);
304    // Consider comma to have side effects if the LHS and RHS both do.
305    if (BinOp->getOpcode() == BinaryOperator::Comma)
306      return BinOp->getLHS()->hasLocalSideEffect() &&
307             BinOp->getRHS()->hasLocalSideEffect();
308
309    return BinOp->isAssignmentOp();
310  }
311  case CompoundAssignOperatorClass:
312    return true;
313
314  case ConditionalOperatorClass: {
315    const ConditionalOperator *Exp = cast<ConditionalOperator>(this);
316    return Exp->getCond()->hasLocalSideEffect()
317           || (Exp->getLHS() && Exp->getLHS()->hasLocalSideEffect())
318           || (Exp->getRHS() && Exp->getRHS()->hasLocalSideEffect());
319  }
320
321  case MemberExprClass:
322  case ArraySubscriptExprClass:
323    // If the base pointer or element is to a volatile pointer/field, accessing
324    // if is a side effect.
325    return getType().isVolatileQualified();
326
327  case CallExprClass:
328    // TODO: check attributes for pure/const.   "void foo() { strlen("bar"); }"
329    // should warn.
330    return true;
331  case ObjCMessageExprClass:
332    return true;
333
334  case CastExprClass:
335    // If this is a cast to void, check the operand.  Otherwise, the result of
336    // the cast is unused.
337    if (getType()->isVoidType())
338      return cast<CastExpr>(this)->getSubExpr()->hasLocalSideEffect();
339    return false;
340
341  case CXXDefaultArgExprClass:
342    return cast<CXXDefaultArgExpr>(this)->getExpr()->hasLocalSideEffect();
343  }
344}
345
346/// isLvalue - C99 6.3.2.1: an lvalue is an expression with an object type or an
347/// incomplete type other than void. Nonarray expressions that can be lvalues:
348///  - name, where name must be a variable
349///  - e[i]
350///  - (e), where e must be an lvalue
351///  - e.name, where e must be an lvalue
352///  - e->name
353///  - *e, the type of e cannot be a function type
354///  - string-constant
355///  - (__real__ e) and (__imag__ e) where e is an lvalue  [GNU extension]
356///  - reference type [C++ [expr]]
357///
358Expr::isLvalueResult Expr::isLvalue() const {
359  // first, check the type (C99 6.3.2.1)
360  if (TR->isFunctionType()) // from isObjectType()
361    return LV_NotObjectType;
362
363  // Allow qualified void which is an incomplete type other than void (yuck).
364  if (TR->isVoidType() && !TR.getCanonicalType().getCVRQualifiers())
365    return LV_IncompleteVoidType;
366
367  if (TR->isReferenceType()) // C++ [expr]
368    return LV_Valid;
369
370  // the type looks fine, now check the expression
371  switch (getStmtClass()) {
372  case StringLiteralClass: // C99 6.5.1p4
373    return LV_Valid;
374  case ArraySubscriptExprClass: // C99 6.5.3p4 (e1[e2] == (*((e1)+(e2))))
375    // For vectors, make sure base is an lvalue (i.e. not a function call).
376    if (cast<ArraySubscriptExpr>(this)->getBase()->getType()->isVectorType())
377      return cast<ArraySubscriptExpr>(this)->getBase()->isLvalue();
378    return LV_Valid;
379  case DeclRefExprClass: // C99 6.5.1p2
380    if (isa<VarDecl>(cast<DeclRefExpr>(this)->getDecl()))
381      return LV_Valid;
382    break;
383  case MemberExprClass: { // C99 6.5.2.3p4
384    const MemberExpr *m = cast<MemberExpr>(this);
385    return m->isArrow() ? LV_Valid : m->getBase()->isLvalue();
386  }
387  case UnaryOperatorClass:
388    if (cast<UnaryOperator>(this)->getOpcode() == UnaryOperator::Deref)
389      return LV_Valid; // C99 6.5.3p4
390
391    if (cast<UnaryOperator>(this)->getOpcode() == UnaryOperator::Real ||
392        cast<UnaryOperator>(this)->getOpcode() == UnaryOperator::Imag)
393      return cast<UnaryOperator>(this)->getSubExpr()->isLvalue();  // GNU.
394    break;
395  case ParenExprClass: // C99 6.5.1p5
396    return cast<ParenExpr>(this)->getSubExpr()->isLvalue();
397  case CompoundLiteralExprClass: // C99 6.5.2.5p5
398    return LV_Valid;
399  case ExtVectorElementExprClass:
400    if (cast<ExtVectorElementExpr>(this)->containsDuplicateElements())
401      return LV_DuplicateVectorComponents;
402    return LV_Valid;
403  case ObjCIvarRefExprClass: // ObjC instance variables are lvalues.
404    return LV_Valid;
405  case PreDefinedExprClass:
406    return LV_Valid;
407  case CXXDefaultArgExprClass:
408    return cast<CXXDefaultArgExpr>(this)->getExpr()->isLvalue();
409  default:
410    break;
411  }
412  return LV_InvalidExpression;
413}
414
415/// isModifiableLvalue - C99 6.3.2.1: an lvalue that does not have array type,
416/// does not have an incomplete type, does not have a const-qualified type, and
417/// if it is a structure or union, does not have any member (including,
418/// recursively, any member or element of all contained aggregates or unions)
419/// with a const-qualified type.
420Expr::isModifiableLvalueResult Expr::isModifiableLvalue() const {
421  isLvalueResult lvalResult = isLvalue();
422
423  switch (lvalResult) {
424  case LV_Valid: break;
425  case LV_NotObjectType: return MLV_NotObjectType;
426  case LV_IncompleteVoidType: return MLV_IncompleteVoidType;
427  case LV_DuplicateVectorComponents: return MLV_DuplicateVectorComponents;
428  case LV_InvalidExpression: return MLV_InvalidExpression;
429  }
430  if (TR.isConstQualified())
431    return MLV_ConstQualified;
432  if (TR->isArrayType())
433    return MLV_ArrayType;
434  if (TR->isIncompleteType())
435    return MLV_IncompleteType;
436
437  if (const RecordType *r = dyn_cast<RecordType>(TR.getCanonicalType())) {
438    if (r->hasConstFields())
439      return MLV_ConstQualified;
440  }
441  return MLV_Valid;
442}
443
444/// hasGlobalStorage - Return true if this expression has static storage
445/// duration.  This means that the address of this expression is a link-time
446/// constant.
447bool Expr::hasGlobalStorage() const {
448  switch (getStmtClass()) {
449  default:
450    return false;
451  case ParenExprClass:
452    return cast<ParenExpr>(this)->getSubExpr()->hasGlobalStorage();
453  case ImplicitCastExprClass:
454    return cast<ImplicitCastExpr>(this)->getSubExpr()->hasGlobalStorage();
455  case CompoundLiteralExprClass:
456    return cast<CompoundLiteralExpr>(this)->isFileScope();
457  case DeclRefExprClass: {
458    const Decl *D = cast<DeclRefExpr>(this)->getDecl();
459    if (const VarDecl *VD = dyn_cast<VarDecl>(D))
460      return VD->hasGlobalStorage();
461    if (isa<FunctionDecl>(D))
462      return true;
463    return false;
464  }
465  case MemberExprClass: {
466    const MemberExpr *M = cast<MemberExpr>(this);
467    return !M->isArrow() && M->getBase()->hasGlobalStorage();
468  }
469  case ArraySubscriptExprClass:
470    return cast<ArraySubscriptExpr>(this)->getBase()->hasGlobalStorage();
471  case PreDefinedExprClass:
472    return true;
473  case CXXDefaultArgExprClass:
474    return cast<CXXDefaultArgExpr>(this)->getExpr()->hasGlobalStorage();
475  }
476}
477
478Expr* Expr::IgnoreParens() {
479  Expr* E = this;
480  while (ParenExpr* P = dyn_cast<ParenExpr>(E))
481    E = P->getSubExpr();
482
483  return E;
484}
485
486/// IgnoreParenCasts - Ignore parentheses and casts.  Strip off any ParenExpr
487/// or CastExprs or ImplicitCastExprs, returning their operand.
488Expr *Expr::IgnoreParenCasts() {
489  Expr *E = this;
490  while (true) {
491    if (ParenExpr *P = dyn_cast<ParenExpr>(E))
492      E = P->getSubExpr();
493    else if (CastExpr *P = dyn_cast<CastExpr>(E))
494      E = P->getSubExpr();
495    else if (ImplicitCastExpr *P = dyn_cast<ImplicitCastExpr>(E))
496      E = P->getSubExpr();
497    else
498      return E;
499  }
500}
501
502
503bool Expr::isConstantExpr(ASTContext &Ctx, SourceLocation *Loc) const {
504  switch (getStmtClass()) {
505  default:
506    if (Loc) *Loc = getLocStart();
507    return false;
508  case ParenExprClass:
509    return cast<ParenExpr>(this)->getSubExpr()->isConstantExpr(Ctx, Loc);
510  case StringLiteralClass:
511  case ObjCStringLiteralClass:
512  case FloatingLiteralClass:
513  case IntegerLiteralClass:
514  case CharacterLiteralClass:
515  case ImaginaryLiteralClass:
516  case TypesCompatibleExprClass:
517  case CXXBoolLiteralExprClass:
518    return true;
519  case CallExprClass: {
520    const CallExpr *CE = cast<CallExpr>(this);
521    llvm::APSInt Result(32);
522    Result.zextOrTrunc(static_cast<uint32_t>(Ctx.getTypeSize(getType())));
523    if (CE->isBuiltinClassifyType(Result))
524      return true;
525    if (CE->isBuiltinConstantExpr())
526      return true;
527    if (Loc) *Loc = getLocStart();
528    return false;
529  }
530  case DeclRefExprClass: {
531    const Decl *D = cast<DeclRefExpr>(this)->getDecl();
532    // Accept address of function.
533    if (isa<EnumConstantDecl>(D) || isa<FunctionDecl>(D))
534      return true;
535    if (Loc) *Loc = getLocStart();
536    if (isa<VarDecl>(D))
537      return TR->isArrayType();
538    return false;
539  }
540  case CompoundLiteralExprClass:
541    if (Loc) *Loc = getLocStart();
542    // Allow "(int []){2,4}", since the array will be converted to a pointer.
543    // Allow "(vector type){2,4}" since the elements are all constant.
544    return TR->isArrayType() || TR->isVectorType();
545  case UnaryOperatorClass: {
546    const UnaryOperator *Exp = cast<UnaryOperator>(this);
547
548    // C99 6.6p9
549    if (Exp->getOpcode() == UnaryOperator::AddrOf) {
550      if (!Exp->getSubExpr()->hasGlobalStorage()) {
551        if (Loc) *Loc = getLocStart();
552        return false;
553      }
554      return true;
555    }
556
557    // Get the operand value.  If this is sizeof/alignof, do not evalute the
558    // operand.  This affects C99 6.6p3.
559    if (!Exp->isSizeOfAlignOfOp() &&
560        Exp->getOpcode() != UnaryOperator::OffsetOf &&
561        !Exp->getSubExpr()->isConstantExpr(Ctx, Loc))
562      return false;
563
564    switch (Exp->getOpcode()) {
565    // Address, indirect, pre/post inc/dec, etc are not valid constant exprs.
566    // See C99 6.6p3.
567    default:
568      if (Loc) *Loc = Exp->getOperatorLoc();
569      return false;
570    case UnaryOperator::Extension:
571      return true;  // FIXME: this is wrong.
572    case UnaryOperator::SizeOf:
573    case UnaryOperator::AlignOf:
574    case UnaryOperator::OffsetOf:
575      // sizeof(vla) is not a constantexpr: C99 6.5.3.4p2.
576      if (!Exp->getSubExpr()->getType()->isConstantSizeType()) {
577        if (Loc) *Loc = Exp->getOperatorLoc();
578        return false;
579      }
580      return true;
581    case UnaryOperator::LNot:
582    case UnaryOperator::Plus:
583    case UnaryOperator::Minus:
584    case UnaryOperator::Not:
585      return true;
586    }
587  }
588  case SizeOfAlignOfTypeExprClass: {
589    const SizeOfAlignOfTypeExpr *Exp = cast<SizeOfAlignOfTypeExpr>(this);
590    // alignof always evaluates to a constant.
591    if (Exp->isSizeOf() && !Exp->getArgumentType()->isVoidType() &&
592        !Exp->getArgumentType()->isConstantSizeType()) {
593      if (Loc) *Loc = Exp->getOperatorLoc();
594      return false;
595    }
596    return true;
597  }
598  case BinaryOperatorClass: {
599    const BinaryOperator *Exp = cast<BinaryOperator>(this);
600
601    // The LHS of a constant expr is always evaluated and needed.
602    if (!Exp->getLHS()->isConstantExpr(Ctx, Loc))
603      return false;
604
605    if (!Exp->getRHS()->isConstantExpr(Ctx, Loc))
606      return false;
607    return true;
608  }
609  case ImplicitCastExprClass:
610  case CastExprClass: {
611    const Expr *SubExpr;
612    SourceLocation CastLoc;
613    if (const CastExpr *C = dyn_cast<CastExpr>(this)) {
614      SubExpr = C->getSubExpr();
615      CastLoc = C->getLParenLoc();
616    } else {
617      SubExpr = cast<ImplicitCastExpr>(this)->getSubExpr();
618      CastLoc = getLocStart();
619    }
620    if (!SubExpr->isConstantExpr(Ctx, Loc)) {
621      if (Loc) *Loc = SubExpr->getLocStart();
622      return false;
623    }
624    return true;
625  }
626  case ConditionalOperatorClass: {
627    const ConditionalOperator *Exp = cast<ConditionalOperator>(this);
628    if (!Exp->getCond()->isConstantExpr(Ctx, Loc) ||
629        // Handle the GNU extension for missing LHS.
630        !(Exp->getLHS() && Exp->getLHS()->isConstantExpr(Ctx, Loc)) ||
631        !Exp->getRHS()->isConstantExpr(Ctx, Loc))
632      return false;
633    return true;
634  }
635  case InitListExprClass: {
636    const InitListExpr *Exp = cast<InitListExpr>(this);
637    unsigned numInits = Exp->getNumInits();
638    for (unsigned i = 0; i < numInits; i++) {
639      if (!Exp->getInit(i)->isConstantExpr(Ctx, Loc)) {
640        if (Loc) *Loc = Exp->getInit(i)->getLocStart();
641        return false;
642      }
643    }
644    return true;
645  }
646  case CXXDefaultArgExprClass:
647    return cast<CXXDefaultArgExpr>(this)->getExpr()->isConstantExpr(Ctx, Loc);
648  }
649}
650
651/// isIntegerConstantExpr - this recursive routine will test if an expression is
652/// an integer constant expression. Note: With the introduction of VLA's in
653/// C99 the result of the sizeof operator is no longer always a constant
654/// expression. The generalization of the wording to include any subexpression
655/// that is not evaluated (C99 6.6p3) means that nonconstant subexpressions
656/// can appear as operands to other operators (e.g. &&, ||, ?:). For instance,
657/// "0 || f()" can be treated as a constant expression. In C90 this expression,
658/// occurring in a context requiring a constant, would have been a constraint
659/// violation. FIXME: This routine currently implements C90 semantics.
660/// To properly implement C99 semantics this routine will need to evaluate
661/// expressions involving operators previously mentioned.
662
663/// FIXME: Pass up a reason why! Invalid operation in i-c-e, division by zero,
664/// comma, etc
665///
666/// FIXME: This should ext-warn on overflow during evaluation!  ISO C does not
667/// permit this.  This includes things like (int)1e1000
668///
669/// FIXME: Handle offsetof.  Two things to do:  Handle GCC's __builtin_offsetof
670/// to support gcc 4.0+  and handle the idiom GCC recognizes with a null pointer
671/// cast+dereference.
672bool Expr::isIntegerConstantExpr(llvm::APSInt &Result, ASTContext &Ctx,
673                                 SourceLocation *Loc, bool isEvaluated) const {
674  switch (getStmtClass()) {
675  default:
676    if (Loc) *Loc = getLocStart();
677    return false;
678  case ParenExprClass:
679    return cast<ParenExpr>(this)->getSubExpr()->
680                     isIntegerConstantExpr(Result, Ctx, Loc, isEvaluated);
681  case IntegerLiteralClass:
682    Result = cast<IntegerLiteral>(this)->getValue();
683    break;
684  case CharacterLiteralClass: {
685    const CharacterLiteral *CL = cast<CharacterLiteral>(this);
686    Result.zextOrTrunc(static_cast<uint32_t>(Ctx.getTypeSize(getType())));
687    Result = CL->getValue();
688    Result.setIsUnsigned(!getType()->isSignedIntegerType());
689    break;
690  }
691  case TypesCompatibleExprClass: {
692    const TypesCompatibleExpr *TCE = cast<TypesCompatibleExpr>(this);
693    Result.zextOrTrunc(static_cast<uint32_t>(Ctx.getTypeSize(getType())));
694    Result = Ctx.typesAreCompatible(TCE->getArgType1(), TCE->getArgType2());
695    break;
696  }
697  case CallExprClass: {
698    const CallExpr *CE = cast<CallExpr>(this);
699    Result.zextOrTrunc(static_cast<uint32_t>(Ctx.getTypeSize(getType())));
700    if (CE->isBuiltinClassifyType(Result))
701      break;
702    if (Loc) *Loc = getLocStart();
703    return false;
704  }
705  case DeclRefExprClass:
706    if (const EnumConstantDecl *D =
707          dyn_cast<EnumConstantDecl>(cast<DeclRefExpr>(this)->getDecl())) {
708      Result = D->getInitVal();
709      break;
710    }
711    if (Loc) *Loc = getLocStart();
712    return false;
713  case UnaryOperatorClass: {
714    const UnaryOperator *Exp = cast<UnaryOperator>(this);
715
716    // Get the operand value.  If this is sizeof/alignof, do not evalute the
717    // operand.  This affects C99 6.6p3.
718    if (!Exp->isSizeOfAlignOfOp() && !Exp->isOffsetOfOp() &&
719        !Exp->getSubExpr()->isIntegerConstantExpr(Result, Ctx, Loc,isEvaluated))
720      return false;
721
722    switch (Exp->getOpcode()) {
723    // Address, indirect, pre/post inc/dec, etc are not valid constant exprs.
724    // See C99 6.6p3.
725    default:
726      if (Loc) *Loc = Exp->getOperatorLoc();
727      return false;
728    case UnaryOperator::Extension:
729      return true;  // FIXME: this is wrong.
730    case UnaryOperator::SizeOf:
731    case UnaryOperator::AlignOf:
732      // Return the result in the right width.
733      Result.zextOrTrunc(static_cast<uint32_t>(Ctx.getTypeSize(getType())));
734
735      // sizeof(void) and __alignof__(void) = 1 as a gcc extension.
736      if (Exp->getSubExpr()->getType()->isVoidType()) {
737        Result = 1;
738        break;
739      }
740
741      // sizeof(vla) is not a constantexpr: C99 6.5.3.4p2.
742      if (!Exp->getSubExpr()->getType()->isConstantSizeType()) {
743        if (Loc) *Loc = Exp->getOperatorLoc();
744        return false;
745      }
746
747      // Get information about the size or align.
748      if (Exp->getSubExpr()->getType()->isFunctionType()) {
749        // GCC extension: sizeof(function) = 1.
750        Result = Exp->getOpcode() == UnaryOperator::AlignOf ? 4 : 1;
751      } else {
752        unsigned CharSize = Ctx.Target.getCharWidth();
753        if (Exp->getOpcode() == UnaryOperator::AlignOf)
754          Result = Ctx.getTypeAlign(Exp->getSubExpr()->getType()) / CharSize;
755        else
756          Result = Ctx.getTypeSize(Exp->getSubExpr()->getType()) / CharSize;
757      }
758      break;
759    case UnaryOperator::LNot: {
760      bool Val = Result == 0;
761      Result.zextOrTrunc(static_cast<uint32_t>(Ctx.getTypeSize(getType())));
762      Result = Val;
763      break;
764    }
765    case UnaryOperator::Plus:
766      break;
767    case UnaryOperator::Minus:
768      Result = -Result;
769      break;
770    case UnaryOperator::Not:
771      Result = ~Result;
772      break;
773    case UnaryOperator::OffsetOf:
774      Result = Exp->evaluateOffsetOf(Ctx);
775    }
776    break;
777  }
778  case SizeOfAlignOfTypeExprClass: {
779    const SizeOfAlignOfTypeExpr *Exp = cast<SizeOfAlignOfTypeExpr>(this);
780
781    // Return the result in the right width.
782    Result.zextOrTrunc(static_cast<uint32_t>(Ctx.getTypeSize(getType())));
783
784    // sizeof(void) and __alignof__(void) = 1 as a gcc extension.
785    if (Exp->getArgumentType()->isVoidType()) {
786      Result = 1;
787      break;
788    }
789
790    // alignof always evaluates to a constant, sizeof does if arg is not VLA.
791    if (Exp->isSizeOf() && !Exp->getArgumentType()->isConstantSizeType()) {
792      if (Loc) *Loc = Exp->getOperatorLoc();
793      return false;
794    }
795
796    // Get information about the size or align.
797    if (Exp->getArgumentType()->isFunctionType()) {
798      // GCC extension: sizeof(function) = 1.
799      Result = Exp->isSizeOf() ? 1 : 4;
800    } else {
801      unsigned CharSize = Ctx.Target.getCharWidth();
802      if (Exp->isSizeOf())
803        Result = Ctx.getTypeSize(Exp->getArgumentType()) / CharSize;
804      else
805        Result = Ctx.getTypeAlign(Exp->getArgumentType()) / CharSize;
806    }
807    break;
808  }
809  case BinaryOperatorClass: {
810    const BinaryOperator *Exp = cast<BinaryOperator>(this);
811
812    // The LHS of a constant expr is always evaluated and needed.
813    if (!Exp->getLHS()->isIntegerConstantExpr(Result, Ctx, Loc, isEvaluated))
814      return false;
815
816    llvm::APSInt RHS(Result);
817
818    // The short-circuiting &&/|| operators don't necessarily evaluate their
819    // RHS.  Make sure to pass isEvaluated down correctly.
820    if (Exp->isLogicalOp()) {
821      bool RHSEval;
822      if (Exp->getOpcode() == BinaryOperator::LAnd)
823        RHSEval = Result != 0;
824      else {
825        assert(Exp->getOpcode() == BinaryOperator::LOr &&"Unexpected logical");
826        RHSEval = Result == 0;
827      }
828
829      if (!Exp->getRHS()->isIntegerConstantExpr(RHS, Ctx, Loc,
830                                                isEvaluated & RHSEval))
831        return false;
832    } else {
833      if (!Exp->getRHS()->isIntegerConstantExpr(RHS, Ctx, Loc, isEvaluated))
834        return false;
835    }
836
837    switch (Exp->getOpcode()) {
838    default:
839      if (Loc) *Loc = getLocStart();
840      return false;
841    case BinaryOperator::Mul:
842      Result *= RHS;
843      break;
844    case BinaryOperator::Div:
845      if (RHS == 0) {
846        if (!isEvaluated) break;
847        if (Loc) *Loc = getLocStart();
848        return false;
849      }
850      Result /= RHS;
851      break;
852    case BinaryOperator::Rem:
853      if (RHS == 0) {
854        if (!isEvaluated) break;
855        if (Loc) *Loc = getLocStart();
856        return false;
857      }
858      Result %= RHS;
859      break;
860    case BinaryOperator::Add: Result += RHS; break;
861    case BinaryOperator::Sub: Result -= RHS; break;
862    case BinaryOperator::Shl:
863      Result <<=
864        static_cast<uint32_t>(RHS.getLimitedValue(Result.getBitWidth()-1));
865      break;
866    case BinaryOperator::Shr:
867      Result >>=
868        static_cast<uint32_t>(RHS.getLimitedValue(Result.getBitWidth()-1));
869      break;
870    case BinaryOperator::LT:  Result = Result < RHS; break;
871    case BinaryOperator::GT:  Result = Result > RHS; break;
872    case BinaryOperator::LE:  Result = Result <= RHS; break;
873    case BinaryOperator::GE:  Result = Result >= RHS; break;
874    case BinaryOperator::EQ:  Result = Result == RHS; break;
875    case BinaryOperator::NE:  Result = Result != RHS; break;
876    case BinaryOperator::And: Result &= RHS; break;
877    case BinaryOperator::Xor: Result ^= RHS; break;
878    case BinaryOperator::Or:  Result |= RHS; break;
879    case BinaryOperator::LAnd:
880      Result = Result != 0 && RHS != 0;
881      break;
882    case BinaryOperator::LOr:
883      Result = Result != 0 || RHS != 0;
884      break;
885
886    case BinaryOperator::Comma:
887      // C99 6.6p3: "shall not contain assignment, ..., or comma operators,
888      // *except* when they are contained within a subexpression that is not
889      // evaluated".  Note that Assignment can never happen due to constraints
890      // on the LHS subexpr, so we don't need to check it here.
891      if (isEvaluated) {
892        if (Loc) *Loc = getLocStart();
893        return false;
894      }
895
896      // The result of the constant expr is the RHS.
897      Result = RHS;
898      return true;
899    }
900
901    assert(!Exp->isAssignmentOp() && "LHS can't be a constant expr!");
902    break;
903  }
904  case ImplicitCastExprClass:
905  case CastExprClass: {
906    const Expr *SubExpr;
907    SourceLocation CastLoc;
908    if (const CastExpr *C = dyn_cast<CastExpr>(this)) {
909      SubExpr = C->getSubExpr();
910      CastLoc = C->getLParenLoc();
911    } else {
912      SubExpr = cast<ImplicitCastExpr>(this)->getSubExpr();
913      CastLoc = getLocStart();
914    }
915
916    // C99 6.6p6: shall only convert arithmetic types to integer types.
917    if (!SubExpr->getType()->isArithmeticType() ||
918        !getType()->isIntegerType()) {
919      if (Loc) *Loc = SubExpr->getLocStart();
920      return false;
921    }
922
923    uint32_t DestWidth = static_cast<uint32_t>(Ctx.getTypeSize(getType()));
924
925    // Handle simple integer->integer casts.
926    if (SubExpr->getType()->isIntegerType()) {
927      if (!SubExpr->isIntegerConstantExpr(Result, Ctx, Loc, isEvaluated))
928        return false;
929
930      // Figure out if this is a truncate, extend or noop cast.
931      // If the input is signed, do a sign extend, noop, or truncate.
932      if (getType()->isBooleanType()) {
933        // Conversion to bool compares against zero.
934        Result = Result != 0;
935        Result.zextOrTrunc(DestWidth);
936      } else if (SubExpr->getType()->isSignedIntegerType())
937        Result.sextOrTrunc(DestWidth);
938      else  // If the input is unsigned, do a zero extend, noop, or truncate.
939        Result.zextOrTrunc(DestWidth);
940      break;
941    }
942
943    // Allow floating constants that are the immediate operands of casts or that
944    // are parenthesized.
945    const Expr *Operand = SubExpr;
946    while (const ParenExpr *PE = dyn_cast<ParenExpr>(Operand))
947      Operand = PE->getSubExpr();
948
949    // If this isn't a floating literal, we can't handle it.
950    const FloatingLiteral *FL = dyn_cast<FloatingLiteral>(Operand);
951    if (!FL) {
952      if (Loc) *Loc = Operand->getLocStart();
953      return false;
954    }
955
956    // If the destination is boolean, compare against zero.
957    if (getType()->isBooleanType()) {
958      Result = !FL->getValue().isZero();
959      Result.zextOrTrunc(DestWidth);
960      break;
961    }
962
963    // Determine whether we are converting to unsigned or signed.
964    bool DestSigned = getType()->isSignedIntegerType();
965
966    // TODO: Warn on overflow, but probably not here: isIntegerConstantExpr can
967    // be called multiple times per AST.
968    uint64_t Space[4];
969    (void)FL->getValue().convertToInteger(Space, DestWidth, DestSigned,
970                                          llvm::APFloat::rmTowardZero);
971    Result = llvm::APInt(DestWidth, 4, Space);
972    break;
973  }
974  case ConditionalOperatorClass: {
975    const ConditionalOperator *Exp = cast<ConditionalOperator>(this);
976
977    if (!Exp->getCond()->isIntegerConstantExpr(Result, Ctx, Loc, isEvaluated))
978      return false;
979
980    const Expr *TrueExp  = Exp->getLHS();
981    const Expr *FalseExp = Exp->getRHS();
982    if (Result == 0) std::swap(TrueExp, FalseExp);
983
984    // Evaluate the false one first, discard the result.
985    if (FalseExp && !FalseExp->isIntegerConstantExpr(Result, Ctx, Loc, false))
986      return false;
987    // Evalute the true one, capture the result.
988    if (TrueExp &&
989        !TrueExp->isIntegerConstantExpr(Result, Ctx, Loc, isEvaluated))
990      return false;
991    break;
992  }
993  case CXXDefaultArgExprClass:
994    return cast<CXXDefaultArgExpr>(this)
995             ->isIntegerConstantExpr(Result, Ctx, Loc, isEvaluated);
996  }
997
998  // Cases that are valid constant exprs fall through to here.
999  Result.setIsUnsigned(getType()->isUnsignedIntegerType());
1000  return true;
1001}
1002
1003/// isNullPointerConstant - C99 6.3.2.3p3 -  Return true if this is either an
1004/// integer constant expression with the value zero, or if this is one that is
1005/// cast to void*.
1006bool Expr::isNullPointerConstant(ASTContext &Ctx) const {
1007  // Strip off a cast to void*, if it exists.
1008  if (const CastExpr *CE = dyn_cast<CastExpr>(this)) {
1009    // Check that it is a cast to void*.
1010    if (const PointerType *PT = CE->getType()->getAsPointerType()) {
1011      QualType Pointee = PT->getPointeeType();
1012      if (Pointee.getCVRQualifiers() == 0 &&
1013          Pointee->isVoidType() &&                                 // to void*
1014          CE->getSubExpr()->getType()->isIntegerType())            // from int.
1015        return CE->getSubExpr()->isNullPointerConstant(Ctx);
1016    }
1017  } else if (const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(this)) {
1018    // Ignore the ImplicitCastExpr type entirely.
1019    return ICE->getSubExpr()->isNullPointerConstant(Ctx);
1020  } else if (const ParenExpr *PE = dyn_cast<ParenExpr>(this)) {
1021    // Accept ((void*)0) as a null pointer constant, as many other
1022    // implementations do.
1023    return PE->getSubExpr()->isNullPointerConstant(Ctx);
1024  } else if (const CXXDefaultArgExpr *DefaultArg
1025               = dyn_cast<CXXDefaultArgExpr>(this)) {
1026    // See through default argument expressions
1027    return DefaultArg->getExpr()->isNullPointerConstant(Ctx);
1028  }
1029
1030  // This expression must be an integer type.
1031  if (!getType()->isIntegerType())
1032    return false;
1033
1034  // If we have an integer constant expression, we need to *evaluate* it and
1035  // test for the value 0.
1036  llvm::APSInt Val(32);
1037  return isIntegerConstantExpr(Val, Ctx, 0, true) && Val == 0;
1038}
1039
1040unsigned ExtVectorElementExpr::getNumElements() const {
1041  return strlen(Accessor.getName());
1042}
1043
1044
1045/// getComponentType - Determine whether the components of this access are
1046/// "point" "color" or "texture" elements.
1047ExtVectorElementExpr::ElementType
1048ExtVectorElementExpr::getElementType() const {
1049  // derive the component type, no need to waste space.
1050  const char *compStr = Accessor.getName();
1051
1052  if (ExtVectorType::getPointAccessorIdx(*compStr) != -1) return Point;
1053  if (ExtVectorType::getColorAccessorIdx(*compStr) != -1) return Color;
1054
1055  assert(ExtVectorType::getTextureAccessorIdx(*compStr) != -1 &&
1056         "getComponentType(): Illegal accessor");
1057  return Texture;
1058}
1059
1060/// containsDuplicateElements - Return true if any element access is
1061/// repeated.
1062bool ExtVectorElementExpr::containsDuplicateElements() const {
1063  const char *compStr = Accessor.getName();
1064  unsigned length = strlen(compStr);
1065
1066  for (unsigned i = 0; i < length-1; i++) {
1067    const char *s = compStr+i;
1068    for (const char c = *s++; *s; s++)
1069      if (c == *s)
1070        return true;
1071  }
1072  return false;
1073}
1074
1075/// getEncodedElementAccess - We encode fields with two bits per component.
1076unsigned ExtVectorElementExpr::getEncodedElementAccess() const {
1077  const char *compStr = Accessor.getName();
1078  unsigned length = getNumElements();
1079
1080  unsigned Result = 0;
1081
1082  while (length--) {
1083    Result <<= 2;
1084    int Idx = ExtVectorType::getAccessorIdx(compStr[length]);
1085    assert(Idx != -1 && "Invalid accessor letter");
1086    Result |= Idx;
1087  }
1088  return Result;
1089}
1090
1091// constructor for instance messages.
1092ObjCMessageExpr::ObjCMessageExpr(Expr *receiver, Selector selInfo,
1093                QualType retType, ObjCMethodDecl *mproto,
1094                SourceLocation LBrac, SourceLocation RBrac,
1095                Expr **ArgExprs, unsigned nargs)
1096  : Expr(ObjCMessageExprClass, retType), SelName(selInfo),
1097    MethodProto(mproto), ClassName(0) {
1098  NumArgs = nargs;
1099  SubExprs = new Expr*[NumArgs+1];
1100  SubExprs[RECEIVER] = receiver;
1101  if (NumArgs) {
1102    for (unsigned i = 0; i != NumArgs; ++i)
1103      SubExprs[i+ARGS_START] = static_cast<Expr *>(ArgExprs[i]);
1104  }
1105  LBracloc = LBrac;
1106  RBracloc = RBrac;
1107}
1108
1109// constructor for class messages.
1110// FIXME: clsName should be typed to ObjCInterfaceType
1111ObjCMessageExpr::ObjCMessageExpr(IdentifierInfo *clsName, Selector selInfo,
1112                QualType retType, ObjCMethodDecl *mproto,
1113                SourceLocation LBrac, SourceLocation RBrac,
1114                Expr **ArgExprs, unsigned nargs)
1115  : Expr(ObjCMessageExprClass, retType), SelName(selInfo),
1116    MethodProto(mproto), ClassName(clsName) {
1117  NumArgs = nargs;
1118  SubExprs = new Expr*[NumArgs+1];
1119  SubExprs[RECEIVER] = 0;
1120  if (NumArgs) {
1121    for (unsigned i = 0; i != NumArgs; ++i)
1122      SubExprs[i+ARGS_START] = static_cast<Expr *>(ArgExprs[i]);
1123  }
1124  LBracloc = LBrac;
1125  RBracloc = RBrac;
1126}
1127
1128
1129bool ChooseExpr::isConditionTrue(ASTContext &C) const {
1130  llvm::APSInt CondVal(32);
1131  bool IsConst = getCond()->isIntegerConstantExpr(CondVal, C);
1132  assert(IsConst && "Condition of choose expr must be i-c-e"); IsConst=IsConst;
1133  return CondVal != 0;
1134}
1135
1136static int64_t evaluateOffsetOf(ASTContext& C, const Expr *E)
1137{
1138  if (const MemberExpr *ME = dyn_cast<MemberExpr>(E)) {
1139    QualType Ty = ME->getBase()->getType();
1140
1141    RecordDecl *RD = Ty->getAsRecordType()->getDecl();
1142    const ASTRecordLayout &RL = C.getASTRecordLayout(RD);
1143    FieldDecl *FD = ME->getMemberDecl();
1144
1145    // FIXME: This is linear time.
1146    unsigned i = 0, e = 0;
1147    for (i = 0, e = RD->getNumMembers(); i != e; i++) {
1148      if (RD->getMember(i) == FD)
1149        break;
1150    }
1151
1152    return RL.getFieldOffset(i) + evaluateOffsetOf(C, ME->getBase());
1153  } else if (const ArraySubscriptExpr *ASE = dyn_cast<ArraySubscriptExpr>(E)) {
1154    const Expr *Base = ASE->getBase();
1155    llvm::APSInt Idx(32);
1156    bool ICE = ASE->getIdx()->isIntegerConstantExpr(Idx, C);
1157    assert(ICE && "Array index is not a constant integer!");
1158
1159    int64_t size = C.getTypeSize(ASE->getType());
1160    size *= Idx.getSExtValue();
1161
1162    return size + evaluateOffsetOf(C, Base);
1163  } else if (isa<CompoundLiteralExpr>(E))
1164    return 0;
1165
1166  assert(0 && "Unknown offsetof subexpression!");
1167  return 0;
1168}
1169
1170int64_t UnaryOperator::evaluateOffsetOf(ASTContext& C) const
1171{
1172  assert(Opc == OffsetOf && "Unary operator not offsetof!");
1173
1174  unsigned CharSize = C.Target.getCharWidth();
1175  return ::evaluateOffsetOf(C, Val) / CharSize;
1176}
1177
1178//===----------------------------------------------------------------------===//
1179//  Child Iterators for iterating over subexpressions/substatements
1180//===----------------------------------------------------------------------===//
1181
1182// DeclRefExpr
1183Stmt::child_iterator DeclRefExpr::child_begin() { return child_iterator(); }
1184Stmt::child_iterator DeclRefExpr::child_end() { return child_iterator(); }
1185
1186// ObjCIvarRefExpr
1187Stmt::child_iterator ObjCIvarRefExpr::child_begin() { return child_iterator(); }
1188Stmt::child_iterator ObjCIvarRefExpr::child_end() { return child_iterator(); }
1189
1190// PreDefinedExpr
1191Stmt::child_iterator PreDefinedExpr::child_begin() { return child_iterator(); }
1192Stmt::child_iterator PreDefinedExpr::child_end() { return child_iterator(); }
1193
1194// IntegerLiteral
1195Stmt::child_iterator IntegerLiteral::child_begin() { return child_iterator(); }
1196Stmt::child_iterator IntegerLiteral::child_end() { return child_iterator(); }
1197
1198// CharacterLiteral
1199Stmt::child_iterator CharacterLiteral::child_begin() { return child_iterator(); }
1200Stmt::child_iterator CharacterLiteral::child_end() { return child_iterator(); }
1201
1202// FloatingLiteral
1203Stmt::child_iterator FloatingLiteral::child_begin() { return child_iterator(); }
1204Stmt::child_iterator FloatingLiteral::child_end() { return child_iterator(); }
1205
1206// ImaginaryLiteral
1207Stmt::child_iterator ImaginaryLiteral::child_begin() {
1208  return reinterpret_cast<Stmt**>(&Val);
1209}
1210Stmt::child_iterator ImaginaryLiteral::child_end() {
1211  return reinterpret_cast<Stmt**>(&Val)+1;
1212}
1213
1214// StringLiteral
1215Stmt::child_iterator StringLiteral::child_begin() { return child_iterator(); }
1216Stmt::child_iterator StringLiteral::child_end() { return child_iterator(); }
1217
1218// ParenExpr
1219Stmt::child_iterator ParenExpr::child_begin() {
1220  return reinterpret_cast<Stmt**>(&Val);
1221}
1222Stmt::child_iterator ParenExpr::child_end() {
1223  return reinterpret_cast<Stmt**>(&Val)+1;
1224}
1225
1226// UnaryOperator
1227Stmt::child_iterator UnaryOperator::child_begin() {
1228  return reinterpret_cast<Stmt**>(&Val);
1229}
1230Stmt::child_iterator UnaryOperator::child_end() {
1231  return reinterpret_cast<Stmt**>(&Val+1);
1232}
1233
1234// SizeOfAlignOfTypeExpr
1235Stmt::child_iterator SizeOfAlignOfTypeExpr::child_begin() {
1236  // If the type is a VLA type (and not a typedef), the size expression of the
1237  // VLA needs to be treated as an executable expression.
1238  if (VariableArrayType* T = dyn_cast<VariableArrayType>(Ty.getTypePtr()))
1239    return child_iterator(T);
1240  else
1241    return child_iterator();
1242}
1243Stmt::child_iterator SizeOfAlignOfTypeExpr::child_end() {
1244  return child_iterator();
1245}
1246
1247// ArraySubscriptExpr
1248Stmt::child_iterator ArraySubscriptExpr::child_begin() {
1249  return reinterpret_cast<Stmt**>(&SubExprs);
1250}
1251Stmt::child_iterator ArraySubscriptExpr::child_end() {
1252  return reinterpret_cast<Stmt**>(&SubExprs)+END_EXPR;
1253}
1254
1255// CallExpr
1256Stmt::child_iterator CallExpr::child_begin() {
1257  return reinterpret_cast<Stmt**>(&SubExprs[0]);
1258}
1259Stmt::child_iterator CallExpr::child_end() {
1260  return reinterpret_cast<Stmt**>(&SubExprs[NumArgs+ARGS_START]);
1261}
1262
1263// MemberExpr
1264Stmt::child_iterator MemberExpr::child_begin() {
1265  return reinterpret_cast<Stmt**>(&Base);
1266}
1267Stmt::child_iterator MemberExpr::child_end() {
1268  return reinterpret_cast<Stmt**>(&Base)+1;
1269}
1270
1271// ExtVectorElementExpr
1272Stmt::child_iterator ExtVectorElementExpr::child_begin() {
1273  return reinterpret_cast<Stmt**>(&Base);
1274}
1275Stmt::child_iterator ExtVectorElementExpr::child_end() {
1276  return reinterpret_cast<Stmt**>(&Base)+1;
1277}
1278
1279// CompoundLiteralExpr
1280Stmt::child_iterator CompoundLiteralExpr::child_begin() {
1281  return reinterpret_cast<Stmt**>(&Init);
1282}
1283Stmt::child_iterator CompoundLiteralExpr::child_end() {
1284  return reinterpret_cast<Stmt**>(&Init)+1;
1285}
1286
1287// ImplicitCastExpr
1288Stmt::child_iterator ImplicitCastExpr::child_begin() {
1289  return reinterpret_cast<Stmt**>(&Op);
1290}
1291Stmt::child_iterator ImplicitCastExpr::child_end() {
1292  return reinterpret_cast<Stmt**>(&Op)+1;
1293}
1294
1295// CastExpr
1296Stmt::child_iterator CastExpr::child_begin() {
1297  return reinterpret_cast<Stmt**>(&Op);
1298}
1299Stmt::child_iterator CastExpr::child_end() {
1300  return reinterpret_cast<Stmt**>(&Op)+1;
1301}
1302
1303// BinaryOperator
1304Stmt::child_iterator BinaryOperator::child_begin() {
1305  return reinterpret_cast<Stmt**>(&SubExprs);
1306}
1307Stmt::child_iterator BinaryOperator::child_end() {
1308  return reinterpret_cast<Stmt**>(&SubExprs)+END_EXPR;
1309}
1310
1311// ConditionalOperator
1312Stmt::child_iterator ConditionalOperator::child_begin() {
1313  return reinterpret_cast<Stmt**>(&SubExprs);
1314}
1315Stmt::child_iterator ConditionalOperator::child_end() {
1316  return reinterpret_cast<Stmt**>(&SubExprs)+END_EXPR;
1317}
1318
1319// AddrLabelExpr
1320Stmt::child_iterator AddrLabelExpr::child_begin() { return child_iterator(); }
1321Stmt::child_iterator AddrLabelExpr::child_end() { return child_iterator(); }
1322
1323// StmtExpr
1324Stmt::child_iterator StmtExpr::child_begin() {
1325  return reinterpret_cast<Stmt**>(&SubStmt);
1326}
1327Stmt::child_iterator StmtExpr::child_end() {
1328  return reinterpret_cast<Stmt**>(&SubStmt)+1;
1329}
1330
1331// TypesCompatibleExpr
1332Stmt::child_iterator TypesCompatibleExpr::child_begin() {
1333  return child_iterator();
1334}
1335
1336Stmt::child_iterator TypesCompatibleExpr::child_end() {
1337  return child_iterator();
1338}
1339
1340// ChooseExpr
1341Stmt::child_iterator ChooseExpr::child_begin() {
1342  return reinterpret_cast<Stmt**>(&SubExprs);
1343}
1344
1345Stmt::child_iterator ChooseExpr::child_end() {
1346  return reinterpret_cast<Stmt**>(&SubExprs)+END_EXPR;
1347}
1348
1349// OverloadExpr
1350Stmt::child_iterator OverloadExpr::child_begin() {
1351  return reinterpret_cast<Stmt**>(&SubExprs[0]);
1352}
1353Stmt::child_iterator OverloadExpr::child_end() {
1354  return reinterpret_cast<Stmt**>(&SubExprs[NumExprs]);
1355}
1356
1357// VAArgExpr
1358Stmt::child_iterator VAArgExpr::child_begin() {
1359  return reinterpret_cast<Stmt**>(&Val);
1360}
1361
1362Stmt::child_iterator VAArgExpr::child_end() {
1363  return reinterpret_cast<Stmt**>(&Val)+1;
1364}
1365
1366// InitListExpr
1367Stmt::child_iterator InitListExpr::child_begin() {
1368  return reinterpret_cast<Stmt**>(&InitExprs[0]);
1369}
1370Stmt::child_iterator InitListExpr::child_end() {
1371  return reinterpret_cast<Stmt**>(&InitExprs[NumInits]);
1372}
1373
1374// ObjCStringLiteral
1375Stmt::child_iterator ObjCStringLiteral::child_begin() {
1376  return child_iterator();
1377}
1378Stmt::child_iterator ObjCStringLiteral::child_end() {
1379  return child_iterator();
1380}
1381
1382// ObjCEncodeExpr
1383Stmt::child_iterator ObjCEncodeExpr::child_begin() { return child_iterator(); }
1384Stmt::child_iterator ObjCEncodeExpr::child_end() { return child_iterator(); }
1385
1386// ObjCSelectorExpr
1387Stmt::child_iterator ObjCSelectorExpr::child_begin() {
1388  return child_iterator();
1389}
1390Stmt::child_iterator ObjCSelectorExpr::child_end() {
1391  return child_iterator();
1392}
1393
1394// ObjCProtocolExpr
1395Stmt::child_iterator ObjCProtocolExpr::child_begin() {
1396  return child_iterator();
1397}
1398Stmt::child_iterator ObjCProtocolExpr::child_end() {
1399  return child_iterator();
1400}
1401
1402// ObjCMessageExpr
1403Stmt::child_iterator ObjCMessageExpr::child_begin() {
1404  return reinterpret_cast<Stmt**>(&SubExprs[0]);
1405}
1406Stmt::child_iterator ObjCMessageExpr::child_end() {
1407  return reinterpret_cast<Stmt**>(&SubExprs[getNumArgs()+ARGS_START]);
1408}
1409
1410