Expr.cpp revision 7c4a191d8be7eac565a64369de072b2a52bf6749 
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
64bool UnaryOperator::isPrefix(Opcode Op) {
65  switch (Op) {
66    case PreInc:
67    case PreDec:
68      return true;
69    default:
70      return false;
71  }
72}
73
74/// getOpcodeStr - Turn an Opcode enum value into the punctuation char it
75/// corresponds to, e.g. "sizeof" or "[pre]++".
76const char *UnaryOperator::getOpcodeStr(Opcode Op) {
77  switch (Op) {
78  default: assert(0 && "Unknown unary operator");
79  case PostInc: return "++";
80  case PostDec: return "--";
81  case PreInc:  return "++";
82  case PreDec:  return "--";
83  case AddrOf:  return "&";
84  case Deref:   return "*";
85  case Plus:    return "+";
86  case Minus:   return "-";
87  case Not:     return "~";
88  case LNot:    return "!";
89  case Real:    return "__real";
90  case Imag:    return "__imag";
91  case SizeOf:  return "sizeof";
92  case AlignOf: return "alignof";
93  case Extension: return "__extension__";
94  case OffsetOf: return "__builtin_offsetof";
95  }
96}
97
98//===----------------------------------------------------------------------===//
99// Postfix Operators.
100//===----------------------------------------------------------------------===//
101
102
103CallExpr::CallExpr(Expr *fn, Expr **args, unsigned numargs, QualType t,
104                   SourceLocation rparenloc)
105  : Expr(CallExprClass, t), NumArgs(numargs) {
106  SubExprs = new Stmt*[numargs+1];
107  SubExprs[FN] = fn;
108  for (unsigned i = 0; i != numargs; ++i)
109    SubExprs[i+ARGS_START] = args[i];
110  RParenLoc = rparenloc;
111}
112
113/// setNumArgs - This changes the number of arguments present in this call.
114/// Any orphaned expressions are deleted by this, and any new operands are set
115/// to null.
116void CallExpr::setNumArgs(unsigned NumArgs) {
117  // No change, just return.
118  if (NumArgs == getNumArgs()) return;
119
120  // If shrinking # arguments, just delete the extras and forgot them.
121  if (NumArgs < getNumArgs()) {
122    for (unsigned i = NumArgs, e = getNumArgs(); i != e; ++i)
123      delete getArg(i);
124    this->NumArgs = NumArgs;
125    return;
126  }
127
128  // Otherwise, we are growing the # arguments.  New an bigger argument array.
129  Stmt **NewSubExprs = new Stmt*[NumArgs+1];
130  // Copy over args.
131  for (unsigned i = 0; i != getNumArgs()+ARGS_START; ++i)
132    NewSubExprs[i] = SubExprs[i];
133  // Null out new args.
134  for (unsigned i = getNumArgs()+ARGS_START; i != NumArgs+ARGS_START; ++i)
135    NewSubExprs[i] = 0;
136
137  delete[] SubExprs;
138  SubExprs = NewSubExprs;
139  this->NumArgs = NumArgs;
140}
141
142bool CallExpr::isBuiltinConstantExpr() const {
143  // All simple function calls (e.g. func()) are implicitly cast to pointer to
144  // function. As a result, we try and obtain the DeclRefExpr from the
145  // ImplicitCastExpr.
146  const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(getCallee());
147  if (!ICE) // FIXME: deal with more complex calls (e.g. (func)(), (*func)()).
148    return false;
149
150  const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(ICE->getSubExpr());
151  if (!DRE)
152    return false;
153
154  const FunctionDecl *FDecl = dyn_cast<FunctionDecl>(DRE->getDecl());
155  if (!FDecl)
156    return false;
157
158  unsigned builtinID = FDecl->getIdentifier()->getBuiltinID();
159  if (!builtinID)
160    return false;
161
162  // We have a builtin that is a constant expression
163  return builtinID == Builtin::BI__builtin___CFStringMakeConstantString ||
164         builtinID == Builtin::BI__builtin_classify_type;
165}
166
167bool CallExpr::isBuiltinClassifyType(llvm::APSInt &Result) const {
168  // The following enum mimics gcc's internal "typeclass.h" file.
169  enum gcc_type_class {
170    no_type_class = -1,
171    void_type_class, integer_type_class, char_type_class,
172    enumeral_type_class, boolean_type_class,
173    pointer_type_class, reference_type_class, offset_type_class,
174    real_type_class, complex_type_class,
175    function_type_class, method_type_class,
176    record_type_class, union_type_class,
177    array_type_class, string_type_class,
178    lang_type_class
179  };
180  Result.setIsSigned(true);
181
182  // All simple function calls (e.g. func()) are implicitly cast to pointer to
183  // function. As a result, we try and obtain the DeclRefExpr from the
184  // ImplicitCastExpr.
185  const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(getCallee());
186  if (!ICE) // FIXME: deal with more complex calls (e.g. (func)(), (*func)()).
187    return false;
188  const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(ICE->getSubExpr());
189  if (!DRE)
190    return false;
191
192  // We have a DeclRefExpr.
193  if (strcmp(DRE->getDecl()->getName(), "__builtin_classify_type") == 0) {
194    // If no argument was supplied, default to "no_type_class". This isn't
195    // ideal, however it's what gcc does.
196    Result = static_cast<uint64_t>(no_type_class);
197    if (NumArgs >= 1) {
198      QualType argType = getArg(0)->getType();
199
200      if (argType->isVoidType())
201        Result = void_type_class;
202      else if (argType->isEnumeralType())
203        Result = enumeral_type_class;
204      else if (argType->isBooleanType())
205        Result = boolean_type_class;
206      else if (argType->isCharType())
207        Result = string_type_class; // gcc doesn't appear to use char_type_class
208      else if (argType->isIntegerType())
209        Result = integer_type_class;
210      else if (argType->isPointerType())
211        Result = pointer_type_class;
212      else if (argType->isReferenceType())
213        Result = reference_type_class;
214      else if (argType->isRealType())
215        Result = real_type_class;
216      else if (argType->isComplexType())
217        Result = complex_type_class;
218      else if (argType->isFunctionType())
219        Result = function_type_class;
220      else if (argType->isStructureType())
221        Result = record_type_class;
222      else if (argType->isUnionType())
223        Result = union_type_class;
224      else if (argType->isArrayType())
225        Result = array_type_class;
226      else if (argType->isUnionType())
227        Result = union_type_class;
228      else  // FIXME: offset_type_class, method_type_class, & lang_type_class?
229        assert(0 && "CallExpr::isBuiltinClassifyType(): unimplemented type");
230    }
231    return true;
232  }
233  return false;
234}
235
236/// getOpcodeStr - Turn an Opcode enum value into the punctuation char it
237/// corresponds to, e.g. "<<=".
238const char *BinaryOperator::getOpcodeStr(Opcode Op) {
239  switch (Op) {
240  default: assert(0 && "Unknown binary operator");
241  case Mul:       return "*";
242  case Div:       return "/";
243  case Rem:       return "%";
244  case Add:       return "+";
245  case Sub:       return "-";
246  case Shl:       return "<<";
247  case Shr:       return ">>";
248  case LT:        return "<";
249  case GT:        return ">";
250  case LE:        return "<=";
251  case GE:        return ">=";
252  case EQ:        return "==";
253  case NE:        return "!=";
254  case And:       return "&";
255  case Xor:       return "^";
256  case Or:        return "|";
257  case LAnd:      return "&&";
258  case LOr:       return "||";
259  case Assign:    return "=";
260  case MulAssign: return "*=";
261  case DivAssign: return "/=";
262  case RemAssign: return "%=";
263  case AddAssign: return "+=";
264  case SubAssign: return "-=";
265  case ShlAssign: return "<<=";
266  case ShrAssign: return ">>=";
267  case AndAssign: return "&=";
268  case XorAssign: return "^=";
269  case OrAssign:  return "|=";
270  case Comma:     return ",";
271  }
272}
273
274InitListExpr::InitListExpr(SourceLocation lbraceloc,
275                           Expr **initexprs, unsigned numinits,
276                           SourceLocation rbraceloc)
277  : Expr(InitListExprClass, QualType()),
278    LBraceLoc(lbraceloc), RBraceLoc(rbraceloc)
279{
280  for (unsigned i = 0; i != numinits; i++)
281    InitExprs.push_back(initexprs[i]);
282}
283
284//===----------------------------------------------------------------------===//
285// Generic Expression Routines
286//===----------------------------------------------------------------------===//
287
288/// hasLocalSideEffect - Return true if this immediate expression has side
289/// effects, not counting any sub-expressions.
290bool Expr::hasLocalSideEffect() const {
291  switch (getStmtClass()) {
292  default:
293    return false;
294  case ParenExprClass:
295    return cast<ParenExpr>(this)->getSubExpr()->hasLocalSideEffect();
296  case UnaryOperatorClass: {
297    const UnaryOperator *UO = cast<UnaryOperator>(this);
298
299    switch (UO->getOpcode()) {
300    default: return false;
301    case UnaryOperator::PostInc:
302    case UnaryOperator::PostDec:
303    case UnaryOperator::PreInc:
304    case UnaryOperator::PreDec:
305      return true;                     // ++/--
306
307    case UnaryOperator::Deref:
308      // Dereferencing a volatile pointer is a side-effect.
309      return getType().isVolatileQualified();
310    case UnaryOperator::Real:
311    case UnaryOperator::Imag:
312      // accessing a piece of a volatile complex is a side-effect.
313      return UO->getSubExpr()->getType().isVolatileQualified();
314
315    case UnaryOperator::Extension:
316      return UO->getSubExpr()->hasLocalSideEffect();
317    }
318  }
319  case BinaryOperatorClass: {
320    const BinaryOperator *BinOp = cast<BinaryOperator>(this);
321    // Consider comma to have side effects if the LHS and RHS both do.
322    if (BinOp->getOpcode() == BinaryOperator::Comma)
323      return BinOp->getLHS()->hasLocalSideEffect() &&
324             BinOp->getRHS()->hasLocalSideEffect();
325
326    return BinOp->isAssignmentOp();
327  }
328  case CompoundAssignOperatorClass:
329    return true;
330
331  case ConditionalOperatorClass: {
332    const ConditionalOperator *Exp = cast<ConditionalOperator>(this);
333    return Exp->getCond()->hasLocalSideEffect()
334           || (Exp->getLHS() && Exp->getLHS()->hasLocalSideEffect())
335           || (Exp->getRHS() && Exp->getRHS()->hasLocalSideEffect());
336  }
337
338  case MemberExprClass:
339  case ArraySubscriptExprClass:
340    // If the base pointer or element is to a volatile pointer/field, accessing
341    // if is a side effect.
342    return getType().isVolatileQualified();
343
344  case CallExprClass:
345    // TODO: check attributes for pure/const.   "void foo() { strlen("bar"); }"
346    // should warn.
347    return true;
348  case ObjCMessageExprClass:
349    return true;
350  case StmtExprClass:
351    // TODO: check the inside of the statement expression
352    return true;
353
354  case CastExprClass:
355    // If this is a cast to void, check the operand.  Otherwise, the result of
356    // the cast is unused.
357    if (getType()->isVoidType())
358      return cast<CastExpr>(this)->getSubExpr()->hasLocalSideEffect();
359    return false;
360
361  case ImplicitCastExprClass:
362    // Check the operand, since implicit casts are inserted by Sema
363    return cast<ImplicitCastExpr>(this)->getSubExpr()->hasLocalSideEffect();
364
365  case CXXDefaultArgExprClass:
366    return cast<CXXDefaultArgExpr>(this)->getExpr()->hasLocalSideEffect();
367  }
368}
369
370/// isLvalue - C99 6.3.2.1: an lvalue is an expression with an object type or an
371/// incomplete type other than void. Nonarray expressions that can be lvalues:
372///  - name, where name must be a variable
373///  - e[i]
374///  - (e), where e must be an lvalue
375///  - e.name, where e must be an lvalue
376///  - e->name
377///  - *e, the type of e cannot be a function type
378///  - string-constant
379///  - (__real__ e) and (__imag__ e) where e is an lvalue  [GNU extension]
380///  - reference type [C++ [expr]]
381///
382Expr::isLvalueResult Expr::isLvalue() const {
383  // first, check the type (C99 6.3.2.1)
384  if (TR->isFunctionType()) // from isObjectType()
385    return LV_NotObjectType;
386
387  // Allow qualified void which is an incomplete type other than void (yuck).
388  if (TR->isVoidType() && !TR.getCanonicalType().getCVRQualifiers())
389    return LV_IncompleteVoidType;
390
391  if (TR->isReferenceType()) // C++ [expr]
392    return LV_Valid;
393
394  // the type looks fine, now check the expression
395  switch (getStmtClass()) {
396  case StringLiteralClass: // C99 6.5.1p4
397    return LV_Valid;
398  case ArraySubscriptExprClass: // C99 6.5.3p4 (e1[e2] == (*((e1)+(e2))))
399    // For vectors, make sure base is an lvalue (i.e. not a function call).
400    if (cast<ArraySubscriptExpr>(this)->getBase()->getType()->isVectorType())
401      return cast<ArraySubscriptExpr>(this)->getBase()->isLvalue();
402    return LV_Valid;
403  case DeclRefExprClass: { // C99 6.5.1p2
404    const Decl *RefdDecl = cast<DeclRefExpr>(this)->getDecl();
405    if (isa<VarDecl>(RefdDecl) || isa<ImplicitParamDecl>(RefdDecl))
406      return LV_Valid;
407    break;
408  }
409  case MemberExprClass: { // C99 6.5.2.3p4
410    const MemberExpr *m = cast<MemberExpr>(this);
411    return m->isArrow() ? LV_Valid : m->getBase()->isLvalue();
412  }
413  case UnaryOperatorClass:
414    if (cast<UnaryOperator>(this)->getOpcode() == UnaryOperator::Deref)
415      return LV_Valid; // C99 6.5.3p4
416
417    if (cast<UnaryOperator>(this)->getOpcode() == UnaryOperator::Real ||
418        cast<UnaryOperator>(this)->getOpcode() == UnaryOperator::Imag ||
419        cast<UnaryOperator>(this)->getOpcode() == UnaryOperator::Extension)
420      return cast<UnaryOperator>(this)->getSubExpr()->isLvalue();  // GNU.
421    break;
422  case ParenExprClass: // C99 6.5.1p5
423    return cast<ParenExpr>(this)->getSubExpr()->isLvalue();
424  case CompoundLiteralExprClass: // C99 6.5.2.5p5
425    return LV_Valid;
426  case ExtVectorElementExprClass:
427    if (cast<ExtVectorElementExpr>(this)->containsDuplicateElements())
428      return LV_DuplicateVectorComponents;
429    return LV_Valid;
430  case ObjCIvarRefExprClass: // ObjC instance variables are lvalues.
431    return LV_Valid;
432  case ObjCPropertyRefExprClass: // FIXME: check if read-only property.
433    return LV_Valid;
434  case PreDefinedExprClass:
435    return (cast<PreDefinedExpr>(this)->getIdentType()
436               == PreDefinedExpr::CXXThis
437            ? LV_InvalidExpression : LV_Valid);
438  case CXXDefaultArgExprClass:
439    return cast<CXXDefaultArgExpr>(this)->getExpr()->isLvalue();
440  default:
441    break;
442  }
443  return LV_InvalidExpression;
444}
445
446/// isModifiableLvalue - C99 6.3.2.1: an lvalue that does not have array type,
447/// does not have an incomplete type, does not have a const-qualified type, and
448/// if it is a structure or union, does not have any member (including,
449/// recursively, any member or element of all contained aggregates or unions)
450/// with a const-qualified type.
451Expr::isModifiableLvalueResult Expr::isModifiableLvalue() const {
452  isLvalueResult lvalResult = isLvalue();
453
454  switch (lvalResult) {
455  case LV_Valid: break;
456  case LV_NotObjectType: return MLV_NotObjectType;
457  case LV_IncompleteVoidType: return MLV_IncompleteVoidType;
458  case LV_DuplicateVectorComponents: return MLV_DuplicateVectorComponents;
459  case LV_InvalidExpression: return MLV_InvalidExpression;
460  }
461  if (TR.isConstQualified())
462    return MLV_ConstQualified;
463  if (TR->isArrayType())
464    return MLV_ArrayType;
465  if (TR->isIncompleteType())
466    return MLV_IncompleteType;
467
468  if (const RecordType *r = dyn_cast<RecordType>(TR.getCanonicalType())) {
469    if (r->hasConstFields())
470      return MLV_ConstQualified;
471  }
472  return MLV_Valid;
473}
474
475/// hasGlobalStorage - Return true if this expression has static storage
476/// duration.  This means that the address of this expression is a link-time
477/// constant.
478bool Expr::hasGlobalStorage() const {
479  switch (getStmtClass()) {
480  default:
481    return false;
482  case ParenExprClass:
483    return cast<ParenExpr>(this)->getSubExpr()->hasGlobalStorage();
484  case ImplicitCastExprClass:
485    return cast<ImplicitCastExpr>(this)->getSubExpr()->hasGlobalStorage();
486  case CompoundLiteralExprClass:
487    return cast<CompoundLiteralExpr>(this)->isFileScope();
488  case DeclRefExprClass: {
489    const Decl *D = cast<DeclRefExpr>(this)->getDecl();
490    if (const VarDecl *VD = dyn_cast<VarDecl>(D))
491      return VD->hasGlobalStorage();
492    if (isa<FunctionDecl>(D))
493      return true;
494    return false;
495  }
496  case MemberExprClass: {
497    const MemberExpr *M = cast<MemberExpr>(this);
498    return !M->isArrow() && M->getBase()->hasGlobalStorage();
499  }
500  case ArraySubscriptExprClass:
501    return cast<ArraySubscriptExpr>(this)->getBase()->hasGlobalStorage();
502  case PreDefinedExprClass:
503    return true;
504  case CXXDefaultArgExprClass:
505    return cast<CXXDefaultArgExpr>(this)->getExpr()->hasGlobalStorage();
506  }
507}
508
509Expr* Expr::IgnoreParens() {
510  Expr* E = this;
511  while (ParenExpr* P = dyn_cast<ParenExpr>(E))
512    E = P->getSubExpr();
513
514  return E;
515}
516
517/// IgnoreParenCasts - Ignore parentheses and casts.  Strip off any ParenExpr
518/// or CastExprs or ImplicitCastExprs, returning their operand.
519Expr *Expr::IgnoreParenCasts() {
520  Expr *E = this;
521  while (true) {
522    if (ParenExpr *P = dyn_cast<ParenExpr>(E))
523      E = P->getSubExpr();
524    else if (CastExpr *P = dyn_cast<CastExpr>(E))
525      E = P->getSubExpr();
526    else if (ImplicitCastExpr *P = dyn_cast<ImplicitCastExpr>(E))
527      E = P->getSubExpr();
528    else
529      return E;
530  }
531}
532
533
534bool Expr::isConstantExpr(ASTContext &Ctx, SourceLocation *Loc) const {
535  switch (getStmtClass()) {
536  default:
537    if (Loc) *Loc = getLocStart();
538    return false;
539  case ParenExprClass:
540    return cast<ParenExpr>(this)->getSubExpr()->isConstantExpr(Ctx, Loc);
541  case StringLiteralClass:
542  case ObjCStringLiteralClass:
543  case FloatingLiteralClass:
544  case IntegerLiteralClass:
545  case CharacterLiteralClass:
546  case ImaginaryLiteralClass:
547  case TypesCompatibleExprClass:
548  case CXXBoolLiteralExprClass:
549    return true;
550  case CallExprClass: {
551    const CallExpr *CE = cast<CallExpr>(this);
552    if (CE->isBuiltinConstantExpr())
553      return true;
554    if (Loc) *Loc = getLocStart();
555    return false;
556  }
557  case DeclRefExprClass: {
558    const Decl *D = cast<DeclRefExpr>(this)->getDecl();
559    // Accept address of function.
560    if (isa<EnumConstantDecl>(D) || isa<FunctionDecl>(D))
561      return true;
562    if (Loc) *Loc = getLocStart();
563    if (isa<VarDecl>(D))
564      return TR->isArrayType();
565    return false;
566  }
567  case CompoundLiteralExprClass:
568    if (Loc) *Loc = getLocStart();
569    // Allow "(int []){2,4}", since the array will be converted to a pointer.
570    // Allow "(vector type){2,4}" since the elements are all constant.
571    return TR->isArrayType() || TR->isVectorType();
572  case UnaryOperatorClass: {
573    const UnaryOperator *Exp = cast<UnaryOperator>(this);
574
575    // C99 6.6p9
576    if (Exp->getOpcode() == UnaryOperator::AddrOf) {
577      if (!Exp->getSubExpr()->hasGlobalStorage()) {
578        if (Loc) *Loc = getLocStart();
579        return false;
580      }
581      return true;
582    }
583
584    // Get the operand value.  If this is sizeof/alignof, do not evalute the
585    // operand.  This affects C99 6.6p3.
586    if (!Exp->isSizeOfAlignOfOp() &&
587        Exp->getOpcode() != UnaryOperator::OffsetOf &&
588        !Exp->getSubExpr()->isConstantExpr(Ctx, Loc))
589      return false;
590
591    switch (Exp->getOpcode()) {
592    // Address, indirect, pre/post inc/dec, etc are not valid constant exprs.
593    // See C99 6.6p3.
594    default:
595      if (Loc) *Loc = Exp->getOperatorLoc();
596      return false;
597    case UnaryOperator::Extension:
598      return true;  // FIXME: this is wrong.
599    case UnaryOperator::SizeOf:
600    case UnaryOperator::AlignOf:
601    case UnaryOperator::OffsetOf:
602      // sizeof(vla) is not a constantexpr: C99 6.5.3.4p2.
603      if (!Exp->getSubExpr()->getType()->isConstantSizeType()) {
604        if (Loc) *Loc = Exp->getOperatorLoc();
605        return false;
606      }
607      return true;
608    case UnaryOperator::LNot:
609    case UnaryOperator::Plus:
610    case UnaryOperator::Minus:
611    case UnaryOperator::Not:
612      return true;
613    }
614  }
615  case SizeOfAlignOfTypeExprClass: {
616    const SizeOfAlignOfTypeExpr *Exp = cast<SizeOfAlignOfTypeExpr>(this);
617    // alignof always evaluates to a constant.
618    if (Exp->isSizeOf() && !Exp->getArgumentType()->isVoidType() &&
619        !Exp->getArgumentType()->isConstantSizeType()) {
620      if (Loc) *Loc = Exp->getOperatorLoc();
621      return false;
622    }
623    return true;
624  }
625  case BinaryOperatorClass: {
626    const BinaryOperator *Exp = cast<BinaryOperator>(this);
627
628    // The LHS of a constant expr is always evaluated and needed.
629    if (!Exp->getLHS()->isConstantExpr(Ctx, Loc))
630      return false;
631
632    if (!Exp->getRHS()->isConstantExpr(Ctx, Loc))
633      return false;
634    return true;
635  }
636  case ImplicitCastExprClass:
637  case CastExprClass: {
638    const Expr *SubExpr;
639    SourceLocation CastLoc;
640    if (const CastExpr *C = dyn_cast<CastExpr>(this)) {
641      SubExpr = C->getSubExpr();
642      CastLoc = C->getLParenLoc();
643    } else {
644      SubExpr = cast<ImplicitCastExpr>(this)->getSubExpr();
645      CastLoc = getLocStart();
646    }
647    if (!SubExpr->isConstantExpr(Ctx, Loc)) {
648      if (Loc) *Loc = SubExpr->getLocStart();
649      return false;
650    }
651    return true;
652  }
653  case ConditionalOperatorClass: {
654    const ConditionalOperator *Exp = cast<ConditionalOperator>(this);
655    if (!Exp->getCond()->isConstantExpr(Ctx, Loc) ||
656        // Handle the GNU extension for missing LHS.
657        !(Exp->getLHS() && Exp->getLHS()->isConstantExpr(Ctx, Loc)) ||
658        !Exp->getRHS()->isConstantExpr(Ctx, Loc))
659      return false;
660    return true;
661  }
662  case InitListExprClass: {
663    const InitListExpr *Exp = cast<InitListExpr>(this);
664    unsigned numInits = Exp->getNumInits();
665    for (unsigned i = 0; i < numInits; i++) {
666      if (!Exp->getInit(i)->isConstantExpr(Ctx, Loc)) {
667        if (Loc) *Loc = Exp->getInit(i)->getLocStart();
668        return false;
669      }
670    }
671    return true;
672  }
673  case CXXDefaultArgExprClass:
674    return cast<CXXDefaultArgExpr>(this)->getExpr()->isConstantExpr(Ctx, Loc);
675  }
676}
677
678/// isIntegerConstantExpr - this recursive routine will test if an expression is
679/// an integer constant expression. Note: With the introduction of VLA's in
680/// C99 the result of the sizeof operator is no longer always a constant
681/// expression. The generalization of the wording to include any subexpression
682/// that is not evaluated (C99 6.6p3) means that nonconstant subexpressions
683/// can appear as operands to other operators (e.g. &&, ||, ?:). For instance,
684/// "0 || f()" can be treated as a constant expression. In C90 this expression,
685/// occurring in a context requiring a constant, would have been a constraint
686/// violation. FIXME: This routine currently implements C90 semantics.
687/// To properly implement C99 semantics this routine will need to evaluate
688/// expressions involving operators previously mentioned.
689
690/// FIXME: Pass up a reason why! Invalid operation in i-c-e, division by zero,
691/// comma, etc
692///
693/// FIXME: This should ext-warn on overflow during evaluation!  ISO C does not
694/// permit this.  This includes things like (int)1e1000
695///
696/// FIXME: Handle offsetof.  Two things to do:  Handle GCC's __builtin_offsetof
697/// to support gcc 4.0+  and handle the idiom GCC recognizes with a null pointer
698/// cast+dereference.
699bool Expr::isIntegerConstantExpr(llvm::APSInt &Result, ASTContext &Ctx,
700                                 SourceLocation *Loc, bool isEvaluated) const {
701  switch (getStmtClass()) {
702  default:
703    if (Loc) *Loc = getLocStart();
704    return false;
705  case ParenExprClass:
706    return cast<ParenExpr>(this)->getSubExpr()->
707                     isIntegerConstantExpr(Result, Ctx, Loc, isEvaluated);
708  case IntegerLiteralClass:
709    Result = cast<IntegerLiteral>(this)->getValue();
710    break;
711  case CharacterLiteralClass: {
712    const CharacterLiteral *CL = cast<CharacterLiteral>(this);
713    Result.zextOrTrunc(static_cast<uint32_t>(Ctx.getTypeSize(getType())));
714    Result = CL->getValue();
715    Result.setIsUnsigned(!getType()->isSignedIntegerType());
716    break;
717  }
718  case TypesCompatibleExprClass: {
719    const TypesCompatibleExpr *TCE = cast<TypesCompatibleExpr>(this);
720    Result.zextOrTrunc(static_cast<uint32_t>(Ctx.getTypeSize(getType())));
721    Result = Ctx.typesAreCompatible(TCE->getArgType1(), TCE->getArgType2());
722    break;
723  }
724  case CallExprClass: {
725    const CallExpr *CE = cast<CallExpr>(this);
726    Result.zextOrTrunc(static_cast<uint32_t>(Ctx.getTypeSize(getType())));
727    if (CE->isBuiltinClassifyType(Result))
728      break;
729    if (Loc) *Loc = getLocStart();
730    return false;
731  }
732  case DeclRefExprClass:
733    if (const EnumConstantDecl *D =
734          dyn_cast<EnumConstantDecl>(cast<DeclRefExpr>(this)->getDecl())) {
735      Result = D->getInitVal();
736      break;
737    }
738    if (Loc) *Loc = getLocStart();
739    return false;
740  case UnaryOperatorClass: {
741    const UnaryOperator *Exp = cast<UnaryOperator>(this);
742
743    // Get the operand value.  If this is sizeof/alignof, do not evalute the
744    // operand.  This affects C99 6.6p3.
745    if (!Exp->isSizeOfAlignOfOp() && !Exp->isOffsetOfOp() &&
746        !Exp->getSubExpr()->isIntegerConstantExpr(Result, Ctx, Loc,isEvaluated))
747      return false;
748
749    switch (Exp->getOpcode()) {
750    // Address, indirect, pre/post inc/dec, etc are not valid constant exprs.
751    // See C99 6.6p3.
752    default:
753      if (Loc) *Loc = Exp->getOperatorLoc();
754      return false;
755    case UnaryOperator::Extension:
756      return true;  // FIXME: this is wrong.
757    case UnaryOperator::SizeOf:
758    case UnaryOperator::AlignOf:
759      // Return the result in the right width.
760      Result.zextOrTrunc(static_cast<uint32_t>(Ctx.getTypeSize(getType())));
761
762      // sizeof(void) and __alignof__(void) = 1 as a gcc extension.
763      if (Exp->getSubExpr()->getType()->isVoidType()) {
764        Result = 1;
765        break;
766      }
767
768      // sizeof(vla) is not a constantexpr: C99 6.5.3.4p2.
769      if (!Exp->getSubExpr()->getType()->isConstantSizeType()) {
770        if (Loc) *Loc = Exp->getOperatorLoc();
771        return false;
772      }
773
774      // Get information about the size or align.
775      if (Exp->getSubExpr()->getType()->isFunctionType()) {
776        // GCC extension: sizeof(function) = 1.
777        Result = Exp->getOpcode() == UnaryOperator::AlignOf ? 4 : 1;
778      } else {
779        unsigned CharSize = Ctx.Target.getCharWidth();
780        if (Exp->getOpcode() == UnaryOperator::AlignOf)
781          Result = Ctx.getTypeAlign(Exp->getSubExpr()->getType()) / CharSize;
782        else
783          Result = Ctx.getTypeSize(Exp->getSubExpr()->getType()) / CharSize;
784      }
785      break;
786    case UnaryOperator::LNot: {
787      bool Val = Result == 0;
788      Result.zextOrTrunc(static_cast<uint32_t>(Ctx.getTypeSize(getType())));
789      Result = Val;
790      break;
791    }
792    case UnaryOperator::Plus:
793      break;
794    case UnaryOperator::Minus:
795      Result = -Result;
796      break;
797    case UnaryOperator::Not:
798      Result = ~Result;
799      break;
800    case UnaryOperator::OffsetOf:
801      Result = Exp->evaluateOffsetOf(Ctx);
802    }
803    break;
804  }
805  case SizeOfAlignOfTypeExprClass: {
806    const SizeOfAlignOfTypeExpr *Exp = cast<SizeOfAlignOfTypeExpr>(this);
807
808    // Return the result in the right width.
809    Result.zextOrTrunc(static_cast<uint32_t>(Ctx.getTypeSize(getType())));
810
811    // sizeof(void) and __alignof__(void) = 1 as a gcc extension.
812    if (Exp->getArgumentType()->isVoidType()) {
813      Result = 1;
814      break;
815    }
816
817    // alignof always evaluates to a constant, sizeof does if arg is not VLA.
818    if (Exp->isSizeOf() && !Exp->getArgumentType()->isConstantSizeType()) {
819      if (Loc) *Loc = Exp->getOperatorLoc();
820      return false;
821    }
822
823    // Get information about the size or align.
824    if (Exp->getArgumentType()->isFunctionType()) {
825      // GCC extension: sizeof(function) = 1.
826      Result = Exp->isSizeOf() ? 1 : 4;
827    } else {
828      unsigned CharSize = Ctx.Target.getCharWidth();
829      if (Exp->isSizeOf())
830        Result = Ctx.getTypeSize(Exp->getArgumentType()) / CharSize;
831      else
832        Result = Ctx.getTypeAlign(Exp->getArgumentType()) / CharSize;
833    }
834    break;
835  }
836  case BinaryOperatorClass: {
837    const BinaryOperator *Exp = cast<BinaryOperator>(this);
838
839    // The LHS of a constant expr is always evaluated and needed.
840    if (!Exp->getLHS()->isIntegerConstantExpr(Result, Ctx, Loc, isEvaluated))
841      return false;
842
843    llvm::APSInt RHS(Result);
844
845    // The short-circuiting &&/|| operators don't necessarily evaluate their
846    // RHS.  Make sure to pass isEvaluated down correctly.
847    if (Exp->isLogicalOp()) {
848      bool RHSEval;
849      if (Exp->getOpcode() == BinaryOperator::LAnd)
850        RHSEval = Result != 0;
851      else {
852        assert(Exp->getOpcode() == BinaryOperator::LOr &&"Unexpected logical");
853        RHSEval = Result == 0;
854      }
855
856      if (!Exp->getRHS()->isIntegerConstantExpr(RHS, Ctx, Loc,
857                                                isEvaluated & RHSEval))
858        return false;
859    } else {
860      if (!Exp->getRHS()->isIntegerConstantExpr(RHS, Ctx, Loc, isEvaluated))
861        return false;
862    }
863
864    switch (Exp->getOpcode()) {
865    default:
866      if (Loc) *Loc = getLocStart();
867      return false;
868    case BinaryOperator::Mul:
869      Result *= RHS;
870      break;
871    case BinaryOperator::Div:
872      if (RHS == 0) {
873        if (!isEvaluated) break;
874        if (Loc) *Loc = getLocStart();
875        return false;
876      }
877      Result /= RHS;
878      break;
879    case BinaryOperator::Rem:
880      if (RHS == 0) {
881        if (!isEvaluated) break;
882        if (Loc) *Loc = getLocStart();
883        return false;
884      }
885      Result %= RHS;
886      break;
887    case BinaryOperator::Add: Result += RHS; break;
888    case BinaryOperator::Sub: Result -= RHS; break;
889    case BinaryOperator::Shl:
890      Result <<=
891        static_cast<uint32_t>(RHS.getLimitedValue(Result.getBitWidth()-1));
892      break;
893    case BinaryOperator::Shr:
894      Result >>=
895        static_cast<uint32_t>(RHS.getLimitedValue(Result.getBitWidth()-1));
896      break;
897    case BinaryOperator::LT:  Result = Result < RHS; break;
898    case BinaryOperator::GT:  Result = Result > RHS; break;
899    case BinaryOperator::LE:  Result = Result <= RHS; break;
900    case BinaryOperator::GE:  Result = Result >= RHS; break;
901    case BinaryOperator::EQ:  Result = Result == RHS; break;
902    case BinaryOperator::NE:  Result = Result != RHS; break;
903    case BinaryOperator::And: Result &= RHS; break;
904    case BinaryOperator::Xor: Result ^= RHS; break;
905    case BinaryOperator::Or:  Result |= RHS; break;
906    case BinaryOperator::LAnd:
907      Result = Result != 0 && RHS != 0;
908      break;
909    case BinaryOperator::LOr:
910      Result = Result != 0 || RHS != 0;
911      break;
912
913    case BinaryOperator::Comma:
914      // C99 6.6p3: "shall not contain assignment, ..., or comma operators,
915      // *except* when they are contained within a subexpression that is not
916      // evaluated".  Note that Assignment can never happen due to constraints
917      // on the LHS subexpr, so we don't need to check it here.
918      if (isEvaluated) {
919        if (Loc) *Loc = getLocStart();
920        return false;
921      }
922
923      // The result of the constant expr is the RHS.
924      Result = RHS;
925      return true;
926    }
927
928    assert(!Exp->isAssignmentOp() && "LHS can't be a constant expr!");
929    break;
930  }
931  case ImplicitCastExprClass:
932  case CastExprClass: {
933    const Expr *SubExpr;
934    SourceLocation CastLoc;
935    if (const CastExpr *C = dyn_cast<CastExpr>(this)) {
936      SubExpr = C->getSubExpr();
937      CastLoc = C->getLParenLoc();
938    } else {
939      SubExpr = cast<ImplicitCastExpr>(this)->getSubExpr();
940      CastLoc = getLocStart();
941    }
942
943    // C99 6.6p6: shall only convert arithmetic types to integer types.
944    if (!SubExpr->getType()->isArithmeticType() ||
945        !getType()->isIntegerType()) {
946      if (Loc) *Loc = SubExpr->getLocStart();
947      // GCC accepts pointers as an extension.
948      // FIXME: check getLangOptions().NoExtensions. At the moment, it doesn't
949      // appear possible to get langOptions() from the Expr.
950      if (SubExpr->getType()->isPointerType()) // && !NoExtensions
951        return true;
952      return false;
953    }
954
955    uint32_t DestWidth = static_cast<uint32_t>(Ctx.getTypeSize(getType()));
956
957    // Handle simple integer->integer casts.
958    if (SubExpr->getType()->isIntegerType()) {
959      if (!SubExpr->isIntegerConstantExpr(Result, Ctx, Loc, isEvaluated))
960        return false;
961
962      // Figure out if this is a truncate, extend or noop cast.
963      // If the input is signed, do a sign extend, noop, or truncate.
964      if (getType()->isBooleanType()) {
965        // Conversion to bool compares against zero.
966        Result = Result != 0;
967        Result.zextOrTrunc(DestWidth);
968      } else if (SubExpr->getType()->isSignedIntegerType())
969        Result.sextOrTrunc(DestWidth);
970      else  // If the input is unsigned, do a zero extend, noop, or truncate.
971        Result.zextOrTrunc(DestWidth);
972      break;
973    }
974
975    // Allow floating constants that are the immediate operands of casts or that
976    // are parenthesized.
977    const Expr *Operand = SubExpr;
978    while (const ParenExpr *PE = dyn_cast<ParenExpr>(Operand))
979      Operand = PE->getSubExpr();
980
981    // If this isn't a floating literal, we can't handle it.
982    const FloatingLiteral *FL = dyn_cast<FloatingLiteral>(Operand);
983    if (!FL) {
984      if (Loc) *Loc = Operand->getLocStart();
985      return false;
986    }
987
988    // If the destination is boolean, compare against zero.
989    if (getType()->isBooleanType()) {
990      Result = !FL->getValue().isZero();
991      Result.zextOrTrunc(DestWidth);
992      break;
993    }
994
995    // Determine whether we are converting to unsigned or signed.
996    bool DestSigned = getType()->isSignedIntegerType();
997
998    // TODO: Warn on overflow, but probably not here: isIntegerConstantExpr can
999    // be called multiple times per AST.
1000    uint64_t Space[4];
1001    (void)FL->getValue().convertToInteger(Space, DestWidth, DestSigned,
1002                                          llvm::APFloat::rmTowardZero);
1003    Result = llvm::APInt(DestWidth, 4, Space);
1004    break;
1005  }
1006  case ConditionalOperatorClass: {
1007    const ConditionalOperator *Exp = cast<ConditionalOperator>(this);
1008
1009    if (!Exp->getCond()->isIntegerConstantExpr(Result, Ctx, Loc, isEvaluated))
1010      return false;
1011
1012    const Expr *TrueExp  = Exp->getLHS();
1013    const Expr *FalseExp = Exp->getRHS();
1014    if (Result == 0) std::swap(TrueExp, FalseExp);
1015
1016    // Evaluate the false one first, discard the result.
1017    if (FalseExp && !FalseExp->isIntegerConstantExpr(Result, Ctx, Loc, false))
1018      return false;
1019    // Evalute the true one, capture the result.
1020    if (TrueExp &&
1021        !TrueExp->isIntegerConstantExpr(Result, Ctx, Loc, isEvaluated))
1022      return false;
1023    break;
1024  }
1025  case CXXDefaultArgExprClass:
1026    return cast<CXXDefaultArgExpr>(this)
1027             ->isIntegerConstantExpr(Result, Ctx, Loc, isEvaluated);
1028  }
1029
1030  // Cases that are valid constant exprs fall through to here.
1031  Result.setIsUnsigned(getType()->isUnsignedIntegerType());
1032  return true;
1033}
1034
1035/// isNullPointerConstant - C99 6.3.2.3p3 -  Return true if this is either an
1036/// integer constant expression with the value zero, or if this is one that is
1037/// cast to void*.
1038bool Expr::isNullPointerConstant(ASTContext &Ctx) const {
1039  // Strip off a cast to void*, if it exists.
1040  if (const CastExpr *CE = dyn_cast<CastExpr>(this)) {
1041    // Check that it is a cast to void*.
1042    if (const PointerType *PT = CE->getType()->getAsPointerType()) {
1043      QualType Pointee = PT->getPointeeType();
1044      if (Pointee.getCVRQualifiers() == 0 &&
1045          Pointee->isVoidType() &&                                 // to void*
1046          CE->getSubExpr()->getType()->isIntegerType())            // from int.
1047        return CE->getSubExpr()->isNullPointerConstant(Ctx);
1048    }
1049  } else if (const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(this)) {
1050    // Ignore the ImplicitCastExpr type entirely.
1051    return ICE->getSubExpr()->isNullPointerConstant(Ctx);
1052  } else if (const ParenExpr *PE = dyn_cast<ParenExpr>(this)) {
1053    // Accept ((void*)0) as a null pointer constant, as many other
1054    // implementations do.
1055    return PE->getSubExpr()->isNullPointerConstant(Ctx);
1056  } else if (const CXXDefaultArgExpr *DefaultArg
1057               = dyn_cast<CXXDefaultArgExpr>(this)) {
1058    // See through default argument expressions
1059    return DefaultArg->getExpr()->isNullPointerConstant(Ctx);
1060  }
1061
1062  // This expression must be an integer type.
1063  if (!getType()->isIntegerType())
1064    return false;
1065
1066  // If we have an integer constant expression, we need to *evaluate* it and
1067  // test for the value 0.
1068  llvm::APSInt Val(32);
1069  return isIntegerConstantExpr(Val, Ctx, 0, true) && Val == 0;
1070}
1071
1072unsigned ExtVectorElementExpr::getNumElements() const {
1073  if (const VectorType *VT = getType()->getAsVectorType())
1074    return VT->getNumElements();
1075  return 1;
1076}
1077
1078/// containsDuplicateElements - Return true if any element access is repeated.
1079bool ExtVectorElementExpr::containsDuplicateElements() const {
1080  const char *compStr = Accessor.getName();
1081  unsigned length = strlen(compStr);
1082
1083  for (unsigned i = 0; i < length-1; i++) {
1084    const char *s = compStr+i;
1085    for (const char c = *s++; *s; s++)
1086      if (c == *s)
1087        return true;
1088  }
1089  return false;
1090}
1091
1092/// getEncodedElementAccess - We encode the fields as a llvm ConstantArray.
1093void ExtVectorElementExpr::getEncodedElementAccess(
1094                                  llvm::SmallVectorImpl<unsigned> &Elts) const {
1095  const char *compStr = Accessor.getName();
1096
1097  bool isHi =   !strcmp(compStr, "hi");
1098  bool isLo =   !strcmp(compStr, "lo");
1099  bool isEven = !strcmp(compStr, "e");
1100  bool isOdd  = !strcmp(compStr, "o");
1101
1102  for (unsigned i = 0, e = getNumElements(); i != e; ++i) {
1103    uint64_t Index;
1104
1105    if (isHi)
1106      Index = e + i;
1107    else if (isLo)
1108      Index = i;
1109    else if (isEven)
1110      Index = 2 * i;
1111    else if (isOdd)
1112      Index = 2 * i + 1;
1113    else
1114      Index = ExtVectorType::getAccessorIdx(compStr[i]);
1115
1116    Elts.push_back(Index);
1117  }
1118}
1119
1120// constructor for instance messages.
1121ObjCMessageExpr::ObjCMessageExpr(Expr *receiver, Selector selInfo,
1122                QualType retType, ObjCMethodDecl *mproto,
1123                SourceLocation LBrac, SourceLocation RBrac,
1124                Expr **ArgExprs, unsigned nargs)
1125  : Expr(ObjCMessageExprClass, retType), SelName(selInfo),
1126    MethodProto(mproto) {
1127  NumArgs = nargs;
1128  SubExprs = new Stmt*[NumArgs+1];
1129  SubExprs[RECEIVER] = receiver;
1130  if (NumArgs) {
1131    for (unsigned i = 0; i != NumArgs; ++i)
1132      SubExprs[i+ARGS_START] = static_cast<Expr *>(ArgExprs[i]);
1133  }
1134  LBracloc = LBrac;
1135  RBracloc = RBrac;
1136}
1137
1138// constructor for class messages.
1139// FIXME: clsName should be typed to ObjCInterfaceType
1140ObjCMessageExpr::ObjCMessageExpr(IdentifierInfo *clsName, Selector selInfo,
1141                QualType retType, ObjCMethodDecl *mproto,
1142                SourceLocation LBrac, SourceLocation RBrac,
1143                Expr **ArgExprs, unsigned nargs)
1144  : Expr(ObjCMessageExprClass, retType), SelName(selInfo),
1145    MethodProto(mproto) {
1146  NumArgs = nargs;
1147  SubExprs = new Stmt*[NumArgs+1];
1148  SubExprs[RECEIVER] = (Expr*) ((uintptr_t) clsName | IsClsMethDeclUnknown);
1149  if (NumArgs) {
1150    for (unsigned i = 0; i != NumArgs; ++i)
1151      SubExprs[i+ARGS_START] = static_cast<Expr *>(ArgExprs[i]);
1152  }
1153  LBracloc = LBrac;
1154  RBracloc = RBrac;
1155}
1156
1157// constructor for class messages.
1158ObjCMessageExpr::ObjCMessageExpr(ObjCInterfaceDecl *cls, Selector selInfo,
1159                                 QualType retType, ObjCMethodDecl *mproto,
1160                                 SourceLocation LBrac, SourceLocation RBrac,
1161                                 Expr **ArgExprs, unsigned nargs)
1162: Expr(ObjCMessageExprClass, retType), SelName(selInfo),
1163MethodProto(mproto) {
1164  NumArgs = nargs;
1165  SubExprs = new Stmt*[NumArgs+1];
1166  SubExprs[RECEIVER] = (Expr*) ((uintptr_t) cls | IsClsMethDeclKnown);
1167  if (NumArgs) {
1168    for (unsigned i = 0; i != NumArgs; ++i)
1169      SubExprs[i+ARGS_START] = static_cast<Expr *>(ArgExprs[i]);
1170  }
1171  LBracloc = LBrac;
1172  RBracloc = RBrac;
1173}
1174
1175ObjCMessageExpr::ClassInfo ObjCMessageExpr::getClassInfo() const {
1176  uintptr_t x = (uintptr_t) SubExprs[RECEIVER];
1177  switch (x & Flags) {
1178    default:
1179      assert(false && "Invalid ObjCMessageExpr.");
1180    case IsInstMeth:
1181      return ClassInfo(0, 0);
1182    case IsClsMethDeclUnknown:
1183      return ClassInfo(0, (IdentifierInfo*) (x & ~Flags));
1184    case IsClsMethDeclKnown: {
1185      ObjCInterfaceDecl* D = (ObjCInterfaceDecl*) (x & ~Flags);
1186      return ClassInfo(D, D->getIdentifier());
1187    }
1188  }
1189}
1190
1191bool ChooseExpr::isConditionTrue(ASTContext &C) const {
1192  llvm::APSInt CondVal(32);
1193  bool IsConst = getCond()->isIntegerConstantExpr(CondVal, C);
1194  assert(IsConst && "Condition of choose expr must be i-c-e"); IsConst=IsConst;
1195  return CondVal != 0;
1196}
1197
1198static int64_t evaluateOffsetOf(ASTContext& C, const Expr *E)
1199{
1200  if (const MemberExpr *ME = dyn_cast<MemberExpr>(E)) {
1201    QualType Ty = ME->getBase()->getType();
1202
1203    RecordDecl *RD = Ty->getAsRecordType()->getDecl();
1204    const ASTRecordLayout &RL = C.getASTRecordLayout(RD);
1205    FieldDecl *FD = ME->getMemberDecl();
1206
1207    // FIXME: This is linear time.
1208    unsigned i = 0, e = 0;
1209    for (i = 0, e = RD->getNumMembers(); i != e; i++) {
1210      if (RD->getMember(i) == FD)
1211        break;
1212    }
1213
1214    return RL.getFieldOffset(i) + evaluateOffsetOf(C, ME->getBase());
1215  } else if (const ArraySubscriptExpr *ASE = dyn_cast<ArraySubscriptExpr>(E)) {
1216    const Expr *Base = ASE->getBase();
1217    llvm::APSInt Idx(32);
1218    bool ICE = ASE->getIdx()->isIntegerConstantExpr(Idx, C);
1219    assert(ICE && "Array index is not a constant integer!");
1220
1221    int64_t size = C.getTypeSize(ASE->getType());
1222    size *= Idx.getSExtValue();
1223
1224    return size + evaluateOffsetOf(C, Base);
1225  } else if (isa<CompoundLiteralExpr>(E))
1226    return 0;
1227
1228  assert(0 && "Unknown offsetof subexpression!");
1229  return 0;
1230}
1231
1232int64_t UnaryOperator::evaluateOffsetOf(ASTContext& C) const
1233{
1234  assert(Opc == OffsetOf && "Unary operator not offsetof!");
1235
1236  unsigned CharSize = C.Target.getCharWidth();
1237  return ::evaluateOffsetOf(C, cast<Expr>(Val)) / CharSize;
1238}
1239
1240//===----------------------------------------------------------------------===//
1241//  Child Iterators for iterating over subexpressions/substatements
1242//===----------------------------------------------------------------------===//
1243
1244// DeclRefExpr
1245Stmt::child_iterator DeclRefExpr::child_begin() { return child_iterator(); }
1246Stmt::child_iterator DeclRefExpr::child_end() { return child_iterator(); }
1247
1248// ObjCIvarRefExpr
1249Stmt::child_iterator ObjCIvarRefExpr::child_begin() { return &Base; }
1250Stmt::child_iterator ObjCIvarRefExpr::child_end() { return &Base+1; }
1251
1252// ObjCPropertyRefExpr
1253Stmt::child_iterator ObjCPropertyRefExpr::child_begin() { return &Base; }
1254Stmt::child_iterator ObjCPropertyRefExpr::child_end() { return &Base+1; }
1255
1256// ObjCSuperRefExpr
1257Stmt::child_iterator ObjCSuperRefExpr::child_begin() { return child_iterator();}
1258Stmt::child_iterator ObjCSuperRefExpr::child_end() { return child_iterator(); }
1259
1260// PreDefinedExpr
1261Stmt::child_iterator PreDefinedExpr::child_begin() { return child_iterator(); }
1262Stmt::child_iterator PreDefinedExpr::child_end() { return child_iterator(); }
1263
1264// IntegerLiteral
1265Stmt::child_iterator IntegerLiteral::child_begin() { return child_iterator(); }
1266Stmt::child_iterator IntegerLiteral::child_end() { return child_iterator(); }
1267
1268// CharacterLiteral
1269Stmt::child_iterator CharacterLiteral::child_begin() { return child_iterator(); }
1270Stmt::child_iterator CharacterLiteral::child_end() { return child_iterator(); }
1271
1272// FloatingLiteral
1273Stmt::child_iterator FloatingLiteral::child_begin() { return child_iterator(); }
1274Stmt::child_iterator FloatingLiteral::child_end() { return child_iterator(); }
1275
1276// ImaginaryLiteral
1277Stmt::child_iterator ImaginaryLiteral::child_begin() { return &Val; }
1278Stmt::child_iterator ImaginaryLiteral::child_end() { return &Val+1; }
1279
1280// StringLiteral
1281Stmt::child_iterator StringLiteral::child_begin() { return child_iterator(); }
1282Stmt::child_iterator StringLiteral::child_end() { return child_iterator(); }
1283
1284// ParenExpr
1285Stmt::child_iterator ParenExpr::child_begin() { return &Val; }
1286Stmt::child_iterator ParenExpr::child_end() { return &Val+1; }
1287
1288// UnaryOperator
1289Stmt::child_iterator UnaryOperator::child_begin() { return &Val; }
1290Stmt::child_iterator UnaryOperator::child_end() { return &Val+1; }
1291
1292// SizeOfAlignOfTypeExpr
1293Stmt::child_iterator SizeOfAlignOfTypeExpr::child_begin() {
1294  // If the type is a VLA type (and not a typedef), the size expression of the
1295  // VLA needs to be treated as an executable expression.
1296  if (VariableArrayType* T = dyn_cast<VariableArrayType>(Ty.getTypePtr()))
1297    return child_iterator(T);
1298  else
1299    return child_iterator();
1300}
1301Stmt::child_iterator SizeOfAlignOfTypeExpr::child_end() {
1302  return child_iterator();
1303}
1304
1305// ArraySubscriptExpr
1306Stmt::child_iterator ArraySubscriptExpr::child_begin() {
1307  return &SubExprs[0];
1308}
1309Stmt::child_iterator ArraySubscriptExpr::child_end() {
1310  return &SubExprs[0]+END_EXPR;
1311}
1312
1313// CallExpr
1314Stmt::child_iterator CallExpr::child_begin() {
1315  return &SubExprs[0];
1316}
1317Stmt::child_iterator CallExpr::child_end() {
1318  return &SubExprs[0]+NumArgs+ARGS_START;
1319}
1320
1321// MemberExpr
1322Stmt::child_iterator MemberExpr::child_begin() { return &Base; }
1323Stmt::child_iterator MemberExpr::child_end() { return &Base+1; }
1324
1325// ExtVectorElementExpr
1326Stmt::child_iterator ExtVectorElementExpr::child_begin() { return &Base; }
1327Stmt::child_iterator ExtVectorElementExpr::child_end() { return &Base+1; }
1328
1329// CompoundLiteralExpr
1330Stmt::child_iterator CompoundLiteralExpr::child_begin() { return &Init; }
1331Stmt::child_iterator CompoundLiteralExpr::child_end() { return &Init+1; }
1332
1333// ImplicitCastExpr
1334Stmt::child_iterator ImplicitCastExpr::child_begin() { return &Op; }
1335Stmt::child_iterator ImplicitCastExpr::child_end() { return &Op+1; }
1336
1337// CastExpr
1338Stmt::child_iterator CastExpr::child_begin() { return &Op; }
1339Stmt::child_iterator CastExpr::child_end() { return &Op+1; }
1340
1341// BinaryOperator
1342Stmt::child_iterator BinaryOperator::child_begin() {
1343  return &SubExprs[0];
1344}
1345Stmt::child_iterator BinaryOperator::child_end() {
1346  return &SubExprs[0]+END_EXPR;
1347}
1348
1349// ConditionalOperator
1350Stmt::child_iterator ConditionalOperator::child_begin() {
1351  return &SubExprs[0];
1352}
1353Stmt::child_iterator ConditionalOperator::child_end() {
1354  return &SubExprs[0]+END_EXPR;
1355}
1356
1357// AddrLabelExpr
1358Stmt::child_iterator AddrLabelExpr::child_begin() { return child_iterator(); }
1359Stmt::child_iterator AddrLabelExpr::child_end() { return child_iterator(); }
1360
1361// StmtExpr
1362Stmt::child_iterator StmtExpr::child_begin() { return &SubStmt; }
1363Stmt::child_iterator StmtExpr::child_end() { return &SubStmt+1; }
1364
1365// TypesCompatibleExpr
1366Stmt::child_iterator TypesCompatibleExpr::child_begin() {
1367  return child_iterator();
1368}
1369
1370Stmt::child_iterator TypesCompatibleExpr::child_end() {
1371  return child_iterator();
1372}
1373
1374// ChooseExpr
1375Stmt::child_iterator ChooseExpr::child_begin() { return &SubExprs[0]; }
1376Stmt::child_iterator ChooseExpr::child_end() { return &SubExprs[0]+END_EXPR; }
1377
1378// OverloadExpr
1379Stmt::child_iterator OverloadExpr::child_begin() { return &SubExprs[0]; }
1380Stmt::child_iterator OverloadExpr::child_end() { return &SubExprs[0]+NumExprs; }
1381
1382// ShuffleVectorExpr
1383Stmt::child_iterator ShuffleVectorExpr::child_begin() {
1384  return &SubExprs[0];
1385}
1386Stmt::child_iterator ShuffleVectorExpr::child_end() {
1387  return &SubExprs[0]+NumExprs;
1388}
1389
1390// VAArgExpr
1391Stmt::child_iterator VAArgExpr::child_begin() { return &Val; }
1392Stmt::child_iterator VAArgExpr::child_end() { return &Val+1; }
1393
1394// InitListExpr
1395Stmt::child_iterator InitListExpr::child_begin() {
1396  return InitExprs.size() ? &InitExprs[0] : 0;
1397}
1398Stmt::child_iterator InitListExpr::child_end() {
1399  return InitExprs.size() ? &InitExprs[0] + InitExprs.size() : 0;
1400}
1401
1402// ObjCStringLiteral
1403Stmt::child_iterator ObjCStringLiteral::child_begin() {
1404  return child_iterator();
1405}
1406Stmt::child_iterator ObjCStringLiteral::child_end() {
1407  return child_iterator();
1408}
1409
1410// ObjCEncodeExpr
1411Stmt::child_iterator ObjCEncodeExpr::child_begin() { return child_iterator(); }
1412Stmt::child_iterator ObjCEncodeExpr::child_end() { return child_iterator(); }
1413
1414// ObjCSelectorExpr
1415Stmt::child_iterator ObjCSelectorExpr::child_begin() {
1416  return child_iterator();
1417}
1418Stmt::child_iterator ObjCSelectorExpr::child_end() {
1419  return child_iterator();
1420}
1421
1422// ObjCProtocolExpr
1423Stmt::child_iterator ObjCProtocolExpr::child_begin() {
1424  return child_iterator();
1425}
1426Stmt::child_iterator ObjCProtocolExpr::child_end() {
1427  return child_iterator();
1428}
1429
1430// ObjCMessageExpr
1431Stmt::child_iterator ObjCMessageExpr::child_begin() {
1432  return getReceiver() ? &SubExprs[0] : &SubExprs[0] + ARGS_START;
1433}
1434Stmt::child_iterator ObjCMessageExpr::child_end() {
1435  return &SubExprs[0]+ARGS_START+getNumArgs();
1436}
1437
1438