lib/AST/Expr.cpp

   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/DeclObjC.h"
  16 #include "clang/AST/ASTContext.h"
  17 #include "clang/AST/RecordLayout.h"
  18 #include "clang/AST/StmtVisitor.h"
  19 #include "clang/Basic/TargetInfo.h"
  20 using 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.
  29 double FloatingLiteral::getValueAsApproximateDouble() const {
  30   llvm::APFloat V = getValue();
  31   V.convert(llvm::APFloat::IEEEdouble, llvm::APFloat::rmNearestTiesToEven);
  32   return V.convertToDouble();
  33 }
  34
  35
  36 StringLiteral::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
  50 StringLiteral::~StringLiteral() {
  51   delete[] StrData;
  52 }
  53
  54 bool UnaryOperator::isPostfix(Opcode Op) {
  55   switch (Op) {
  56   case PostInc:
  57   case PostDec:
  58     return true;
  59   default:
  60     return false;
  61   }
  62 }
  63
  64 bool 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]++".
  76 const 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
 103 CallExpr::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.
 116 void 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
 142 bool 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
 167 bool 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. "<<=".
 238 const 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
 274 InitListExpr::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.
 290 bool 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     // Statement exprs don't logically have side effects themselves, but are
 352     // sometimes used in macros in ways that give them a type that is unused.
 353     // For example ({ blah; foo(); }) will end up with a type if foo has a type.
 354     // however, if the result of the stmt expr is dead, we don't want to emit a
 355     // warning.
 356     const CompoundStmt *CS = cast<StmtExpr>(this)->getSubStmt();
 357     if (!CS->body_empty())
 358       if (const Expr *E = dyn_cast<Expr>(CS->body_back()))
 359         return E->hasLocalSideEffect();
 360     return false;
 361   }
 362   case ExplicitCastExprClass:
 363   case CXXFunctionalCastExprClass:
 364     // If this is a cast to void, check the operand.  Otherwise, the result of
 365     // the cast is unused.
 366     if (getType()->isVoidType())
 367       return cast<CastExpr>(this)->getSubExpr()->hasLocalSideEffect();
 368     return false;
 369
 370   case ImplicitCastExprClass:
 371     // Check the operand, since implicit casts are inserted by Sema
 372     return cast<ImplicitCastExpr>(this)->getSubExpr()->hasLocalSideEffect();
 373
 374   case CXXDefaultArgExprClass:
 375     return cast<CXXDefaultArgExpr>(this)->getExpr()->hasLocalSideEffect();
 376   }
 377 }
 378
 379 /// isLvalue - C99 6.3.2.1: an lvalue is an expression with an object type or an
 380 /// incomplete type other than void. Nonarray expressions that can be lvalues:
 381 ///  - name, where name must be a variable
 382 ///  - e[i]
 383 ///  - (e), where e must be an lvalue
 384 ///  - e.name, where e must be an lvalue
 385 ///  - e->name
 386 ///  - *e, the type of e cannot be a function type
 387 ///  - string-constant
 388 ///  - (__real__ e) and (__imag__ e) where e is an lvalue  [GNU extension]
 389 ///  - reference type [C++ [expr]]
 390 ///
 391 Expr::isLvalueResult Expr::isLvalue(ASTContext &Ctx) const {
 392   // first, check the type (C99 6.3.2.1)
 393   if (TR->isFunctionType()) // from isObjectType()
 394     return LV_NotObjectType;
 395
 396   // Allow qualified void which is an incomplete type other than void (yuck).
 397   if (TR->isVoidType() && !Ctx.getCanonicalType(TR).getCVRQualifiers())
 398     return LV_IncompleteVoidType;
 399
 400   if (TR->isReferenceType()) // C++ [expr]
 401     return LV_Valid;
 402
 403   // the type looks fine, now check the expression
 404   switch (getStmtClass()) {
 405   case StringLiteralClass: // C99 6.5.1p4
 406     return LV_Valid;
 407   case ArraySubscriptExprClass: // C99 6.5.3p4 (e1[e2] == (*((e1)+(e2))))
 408     // For vectors, make sure base is an lvalue (i.e. not a function call).
 409     if (cast<ArraySubscriptExpr>(this)->getBase()->getType()->isVectorType())
 410       return cast<ArraySubscriptExpr>(this)->getBase()->isLvalue(Ctx);
 411     return LV_Valid;
 412   case DeclRefExprClass: { // C99 6.5.1p2
 413     const Decl *RefdDecl = cast<DeclRefExpr>(this)->getDecl();
 414     if (isa<VarDecl>(RefdDecl) || isa<ImplicitParamDecl>(RefdDecl))
 415       return LV_Valid;
 416     break;
 417   }
 418   case MemberExprClass: { // C99 6.5.2.3p4
 419     const MemberExpr *m = cast<MemberExpr>(this);
 420     return m->isArrow() ? LV_Valid : m->getBase()->isLvalue(Ctx);
 421   }
 422   case UnaryOperatorClass:
 423     if (cast<UnaryOperator>(this)->getOpcode() == UnaryOperator::Deref)
 424       return LV_Valid; // C99 6.5.3p4
 425
 426     if (cast<UnaryOperator>(this)->getOpcode() == UnaryOperator::Real ||
 427         cast<UnaryOperator>(this)->getOpcode() == UnaryOperator::Imag ||
 428         cast<UnaryOperator>(this)->getOpcode() == UnaryOperator::Extension)
 429       return cast<UnaryOperator>(this)->getSubExpr()->isLvalue(Ctx);  // GNU.
 430     break;
 431   case ParenExprClass: // C99 6.5.1p5
 432     return cast<ParenExpr>(this)->getSubExpr()->isLvalue(Ctx);
 433   case CompoundLiteralExprClass: // C99 6.5.2.5p5
 434     return LV_Valid;
 435   case ExtVectorElementExprClass:
 436     if (cast<ExtVectorElementExpr>(this)->containsDuplicateElements())
 437       return LV_DuplicateVectorComponents;
 438     return LV_Valid;
 439   case ObjCIvarRefExprClass: // ObjC instance variables are lvalues.
 440     return LV_Valid;
 441   case ObjCPropertyRefExprClass: // FIXME: check if read-only property.
 442     return LV_Valid;
 443   case PredefinedExprClass:
 444     return (cast<PredefinedExpr>(this)->getIdentType()
 445                == PredefinedExpr::CXXThis
 446             ? LV_InvalidExpression : LV_Valid);
 447   case CXXDefaultArgExprClass:
 448     return cast<CXXDefaultArgExpr>(this)->getExpr()->isLvalue(Ctx);
 449   default:
 450     break;
 451   }
 452   return LV_InvalidExpression;
 453 }
 454
 455 /// isModifiableLvalue - C99 6.3.2.1: an lvalue that does not have array type,
 456 /// does not have an incomplete type, does not have a const-qualified type, and
 457 /// if it is a structure or union, does not have any member (including,
 458 /// recursively, any member or element of all contained aggregates or unions)
 459 /// with a const-qualified type.
 460 Expr::isModifiableLvalueResult Expr::isModifiableLvalue(ASTContext &Ctx) const {
 461   isLvalueResult lvalResult = isLvalue(Ctx);
 462
 463   switch (lvalResult) {
 464   case LV_Valid: break;
 465   case LV_NotObjectType: return MLV_NotObjectType;
 466   case LV_IncompleteVoidType: return MLV_IncompleteVoidType;
 467   case LV_DuplicateVectorComponents: return MLV_DuplicateVectorComponents;
 468   case LV_InvalidExpression: return MLV_InvalidExpression;
 469   }
 470
 471   QualType CT = Ctx.getCanonicalType(getType());
 472
 473   if (CT.isConstQualified())
 474     return MLV_ConstQualified;
 475   if (CT->isArrayType())
 476     return MLV_ArrayType;
 477   if (CT->isIncompleteType())
 478     return MLV_IncompleteType;
 479
 480   if (const RecordType *r = CT->getAsRecordType()) {
 481     if (r->hasConstFields())
 482       return MLV_ConstQualified;
 483   }
 484   return MLV_Valid;
 485 }
 486
 487 /// hasGlobalStorage - Return true if this expression has static storage
 488 /// duration.  This means that the address of this expression is a link-time
 489 /// constant.
 490 bool Expr::hasGlobalStorage() const {
 491   switch (getStmtClass()) {
 492   default:
 493     return false;
 494   case ParenExprClass:
 495     return cast<ParenExpr>(this)->getSubExpr()->hasGlobalStorage();
 496   case ImplicitCastExprClass:
 497     return cast<ImplicitCastExpr>(this)->getSubExpr()->hasGlobalStorage();
 498   case CompoundLiteralExprClass:
 499     return cast<CompoundLiteralExpr>(this)->isFileScope();
 500   case DeclRefExprClass: {
 501     const Decl *D = cast<DeclRefExpr>(this)->getDecl();
 502     if (const VarDecl *VD = dyn_cast<VarDecl>(D))
 503       return VD->hasGlobalStorage();
 504     if (isa<FunctionDecl>(D))
 505       return true;
 506     return false;
 507   }
 508   case MemberExprClass: {
 509     const MemberExpr *M = cast<MemberExpr>(this);
 510     return !M->isArrow() && M->getBase()->hasGlobalStorage();
 511   }
 512   case ArraySubscriptExprClass:
 513     return cast<ArraySubscriptExpr>(this)->getBase()->hasGlobalStorage();
 514   case PredefinedExprClass:
 515     return true;
 516   case CXXDefaultArgExprClass:
 517     return cast<CXXDefaultArgExpr>(this)->getExpr()->hasGlobalStorage();
 518   }
 519 }
 520
 521 Expr* Expr::IgnoreParens() {
 522   Expr* E = this;
 523   while (ParenExpr* P = dyn_cast<ParenExpr>(E))
 524     E = P->getSubExpr();
 525
 526   return E;
 527 }
 528
 529 /// IgnoreParenCasts - Ignore parentheses and casts.  Strip off any ParenExpr
 530 /// or CastExprs or ImplicitCastExprs, returning their operand.
 531 Expr *Expr::IgnoreParenCasts() {
 532   Expr *E = this;
 533   while (true) {
 534     if (ParenExpr *P = dyn_cast<ParenExpr>(E))
 535       E = P->getSubExpr();
 536     else if (CastExpr *P = dyn_cast<CastExpr>(E))
 537       E = P->getSubExpr();
 538     else
 539       return E;
 540   }
 541 }
 542
 543
 544 bool Expr::isConstantExpr(ASTContext &Ctx, SourceLocation *Loc) const {
 545   switch (getStmtClass()) {
 546   default:
 547     if (Loc) *Loc = getLocStart();
 548     return false;
 549   case ParenExprClass:
 550     return cast<ParenExpr>(this)->getSubExpr()->isConstantExpr(Ctx, Loc);
 551   case StringLiteralClass:
 552   case ObjCStringLiteralClass:
 553   case FloatingLiteralClass:
 554   case IntegerLiteralClass:
 555   case CharacterLiteralClass:
 556   case ImaginaryLiteralClass:
 557   case TypesCompatibleExprClass:
 558   case CXXBoolLiteralExprClass:
 559   case AddrLabelExprClass:
 560     return true;
 561   case CallExprClass: {
 562     const CallExpr *CE = cast<CallExpr>(this);
 563     if (CE->isBuiltinConstantExpr())
 564       return true;
 565     if (Loc) *Loc = getLocStart();
 566     return false;
 567   }
 568   case DeclRefExprClass: {
 569     const Decl *D = cast<DeclRefExpr>(this)->getDecl();
 570     // Accept address of function.
 571     if (isa<EnumConstantDecl>(D) || isa<FunctionDecl>(D))
 572       return true;
 573     if (Loc) *Loc = getLocStart();
 574     if (isa<VarDecl>(D))
 575       return TR->isArrayType();
 576     return false;
 577   }
 578   case CompoundLiteralExprClass:
 579     if (Loc) *Loc = getLocStart();
 580     // Allow "(int []){2,4}", since the array will be converted to a pointer.
 581     // Allow "(vector type){2,4}" since the elements are all constant.
 582     return TR->isArrayType() || TR->isVectorType();
 583   case UnaryOperatorClass: {
 584     const UnaryOperator *Exp = cast<UnaryOperator>(this);
 585
 586     // C99 6.6p9
 587     if (Exp->getOpcode() == UnaryOperator::AddrOf) {
 588       if (!Exp->getSubExpr()->hasGlobalStorage()) {
 589         if (Loc) *Loc = getLocStart();
 590         return false;
 591       }
 592       return true;
 593     }
 594
 595     // Get the operand value.  If this is sizeof/alignof, do not evalute the
 596     // operand.  This affects C99 6.6p3.
 597     if (!Exp->isSizeOfAlignOfOp() &&
 598         Exp->getOpcode() != UnaryOperator::OffsetOf &&
 599         !Exp->getSubExpr()->isConstantExpr(Ctx, Loc))
 600       return false;
 601
 602     switch (Exp->getOpcode()) {
 603     // Address, indirect, pre/post inc/dec, etc are not valid constant exprs.
 604     // See C99 6.6p3.
 605     default:
 606       if (Loc) *Loc = Exp->getOperatorLoc();
 607       return false;
 608     case UnaryOperator::Extension:
 609       return true;  // FIXME: this is wrong.
 610     case UnaryOperator::SizeOf:
 611     case UnaryOperator::AlignOf:
 612     case UnaryOperator::OffsetOf:
 613       // sizeof(vla) is not a constantexpr: C99 6.5.3.4p2.
 614       if (!Exp->getSubExpr()->getType()->isConstantSizeType()) {
 615         if (Loc) *Loc = Exp->getOperatorLoc();
 616         return false;
 617       }
 618       return true;
 619     case UnaryOperator::LNot:
 620     case UnaryOperator::Plus:
 621     case UnaryOperator::Minus:
 622     case UnaryOperator::Not:
 623       return true;
 624     }
 625   }
 626   case SizeOfAlignOfTypeExprClass: {
 627     const SizeOfAlignOfTypeExpr *Exp = cast<SizeOfAlignOfTypeExpr>(this);
 628     // alignof always evaluates to a constant.
 629     if (Exp->isSizeOf() && !Exp->getArgumentType()->isVoidType() &&
 630         !Exp->getArgumentType()->isConstantSizeType()) {
 631       if (Loc) *Loc = Exp->getOperatorLoc();
 632       return false;
 633     }
 634     return true;
 635   }
 636   case BinaryOperatorClass: {
 637     const BinaryOperator *Exp = cast<BinaryOperator>(this);
 638
 639     // The LHS of a constant expr is always evaluated and needed.
 640     if (!Exp->getLHS()->isConstantExpr(Ctx, Loc))
 641       return false;
 642
 643     if (!Exp->getRHS()->isConstantExpr(Ctx, Loc))
 644       return false;
 645     return true;
 646   }
 647   case ImplicitCastExprClass:
 648   case ExplicitCastExprClass:
 649   case CXXFunctionalCastExprClass: {
 650     const Expr *SubExpr = cast<CastExpr>(this)->getSubExpr();
 651     SourceLocation CastLoc = getLocStart();
 652     if (!SubExpr->isConstantExpr(Ctx, Loc)) {
 653       if (Loc) *Loc = SubExpr->getLocStart();
 654       return false;
 655     }
 656     return true;
 657   }
 658   case ConditionalOperatorClass: {
 659     const ConditionalOperator *Exp = cast<ConditionalOperator>(this);
 660     if (!Exp->getCond()->isConstantExpr(Ctx, Loc) ||
 661         // Handle the GNU extension for missing LHS.
 662         !(Exp->getLHS() && Exp->getLHS()->isConstantExpr(Ctx, Loc)) ||
 663         !Exp->getRHS()->isConstantExpr(Ctx, Loc))
 664       return false;
 665     return true;
 666   }
 667   case InitListExprClass: {
 668     const InitListExpr *Exp = cast<InitListExpr>(this);
 669     unsigned numInits = Exp->getNumInits();
 670     for (unsigned i = 0; i < numInits; i++) {
 671       if (!Exp->getInit(i)->isConstantExpr(Ctx, Loc)) {
 672         if (Loc) *Loc = Exp->getInit(i)->getLocStart();
 673         return false;
 674       }
 675     }
 676     return true;
 677   }
 678   case CXXDefaultArgExprClass:
 679     return cast<CXXDefaultArgExpr>(this)->getExpr()->isConstantExpr(Ctx, Loc);
 680   }
 681 }
 682
 683 /// isIntegerConstantExpr - this recursive routine will test if an expression is
 684 /// an integer constant expression. Note: With the introduction of VLA's in
 685 /// C99 the result of the sizeof operator is no longer always a constant
 686 /// expression. The generalization of the wording to include any subexpression
 687 /// that is not evaluated (C99 6.6p3) means that nonconstant subexpressions
 688 /// can appear as operands to other operators (e.g. &&, ||, ?:). For instance,
 689 /// "0 || f()" can be treated as a constant expression. In C90 this expression,
 690 /// occurring in a context requiring a constant, would have been a constraint
 691 /// violation. FIXME: This routine currently implements C90 semantics.
 692 /// To properly implement C99 semantics this routine will need to evaluate
 693 /// expressions involving operators previously mentioned.
 694
 695 /// FIXME: Pass up a reason why! Invalid operation in i-c-e, division by zero,
 696 /// comma, etc
 697 ///
 698 /// FIXME: This should ext-warn on overflow during evaluation!  ISO C does not
 699 /// permit this.  This includes things like (int)1e1000
 700 ///
 701 /// FIXME: Handle offsetof.  Two things to do:  Handle GCC's __builtin_offsetof
 702 /// to support gcc 4.0+  and handle the idiom GCC recognizes with a null pointer
 703 /// cast+dereference.
 704 bool Expr::isIntegerConstantExpr(llvm::APSInt &Result, ASTContext &Ctx,
 705                                  SourceLocation *Loc, bool isEvaluated) const {
 706   switch (getStmtClass()) {
 707   default:
 708     if (Loc) *Loc = getLocStart();
 709     return false;
 710   case ParenExprClass:
 711     return cast<ParenExpr>(this)->getSubExpr()->
 712                      isIntegerConstantExpr(Result, Ctx, Loc, isEvaluated);
 713   case IntegerLiteralClass:
 714     Result = cast<IntegerLiteral>(this)->getValue();
 715     break;
 716   case CharacterLiteralClass: {
 717     const CharacterLiteral *CL = cast<CharacterLiteral>(this);
 718     Result.zextOrTrunc(static_cast<uint32_t>(Ctx.getTypeSize(getType())));
 719     Result = CL->getValue();
 720     Result.setIsUnsigned(!getType()->isSignedIntegerType());
 721     break;
 722   }
 723   case CXXZeroInitValueExprClass:
 724     Result.clear();
 725     break;
 726   case TypesCompatibleExprClass: {
 727     const TypesCompatibleExpr *TCE = cast<TypesCompatibleExpr>(this);
 728     Result.zextOrTrunc(static_cast<uint32_t>(Ctx.getTypeSize(getType())));
 729     Result = Ctx.typesAreCompatible(TCE->getArgType1(), TCE->getArgType2());
 730     break;
 731   }
 732   case CallExprClass: {
 733     const CallExpr *CE = cast<CallExpr>(this);
 734     Result.zextOrTrunc(static_cast<uint32_t>(Ctx.getTypeSize(getType())));
 735     if (CE->isBuiltinClassifyType(Result))
 736       break;
 737     if (Loc) *Loc = getLocStart();
 738     return false;
 739   }
 740   case DeclRefExprClass:
 741     if (const EnumConstantDecl *D =
 742           dyn_cast<EnumConstantDecl>(cast<DeclRefExpr>(this)->getDecl())) {
 743       Result = D->getInitVal();
 744       break;
 745     }
 746     if (Loc) *Loc = getLocStart();
 747     return false;
 748   case UnaryOperatorClass: {
 749     const UnaryOperator *Exp = cast<UnaryOperator>(this);
 750
 751     // Get the operand value.  If this is sizeof/alignof, do not evalute the
 752     // operand.  This affects C99 6.6p3.
 753     if (!Exp->isSizeOfAlignOfOp() && !Exp->isOffsetOfOp() &&
 754         !Exp->getSubExpr()->isIntegerConstantExpr(Result, Ctx, Loc,isEvaluated))
 755       return false;
 756
 757     switch (Exp->getOpcode()) {
 758     // Address, indirect, pre/post inc/dec, etc are not valid constant exprs.
 759     // See C99 6.6p3.
 760     default:
 761       if (Loc) *Loc = Exp->getOperatorLoc();
 762       return false;
 763     case UnaryOperator::Extension:
 764       return true;  // FIXME: this is wrong.
 765     case UnaryOperator::SizeOf:
 766     case UnaryOperator::AlignOf:
 767       // Return the result in the right width.
 768       Result.zextOrTrunc(static_cast<uint32_t>(Ctx.getTypeSize(getType())));
 769
 770       // sizeof(void) and __alignof__(void) = 1 as a gcc extension.
 771       if (Exp->getSubExpr()->getType()->isVoidType()) {
 772         Result = 1;
 773         break;
 774       }
 775
 776       // sizeof(vla) is not a constantexpr: C99 6.5.3.4p2.
 777       if (!Exp->getSubExpr()->getType()->isConstantSizeType()) {
 778         if (Loc) *Loc = Exp->getOperatorLoc();
 779         return false;
 780       }
 781
 782       // Get information about the size or align.
 783       if (Exp->getSubExpr()->getType()->isFunctionType()) {
 784         // GCC extension: sizeof(function) = 1.
 785         Result = Exp->getOpcode() == UnaryOperator::AlignOf ? 4 : 1;
 786       } else {
 787         unsigned CharSize = Ctx.Target.getCharWidth();
 788         if (Exp->getOpcode() == UnaryOperator::AlignOf)
 789           Result = Ctx.getTypeAlign(Exp->getSubExpr()->getType()) / CharSize;
 790         else
 791           Result = Ctx.getTypeSize(Exp->getSubExpr()->getType()) / CharSize;
 792       }
 793       break;
 794     case UnaryOperator::LNot: {
 795       bool Val = Result == 0;
 796       Result.zextOrTrunc(static_cast<uint32_t>(Ctx.getTypeSize(getType())));
 797       Result = Val;
 798       break;
 799     }
 800     case UnaryOperator::Plus:
 801       break;
 802     case UnaryOperator::Minus:
 803       Result = -Result;
 804       break;
 805     case UnaryOperator::Not:
 806       Result = ~Result;
 807       break;
 808     case UnaryOperator::OffsetOf:
 809       Result = Exp->evaluateOffsetOf(Ctx);
 810     }
 811     break;
 812   }
 813   case SizeOfAlignOfTypeExprClass: {
 814     const SizeOfAlignOfTypeExpr *Exp = cast<SizeOfAlignOfTypeExpr>(this);
 815
 816     // Return the result in the right width.
 817     Result.zextOrTrunc(static_cast<uint32_t>(Ctx.getTypeSize(getType())));
 818
 819     // sizeof(void) and __alignof__(void) = 1 as a gcc extension.
 820     if (Exp->getArgumentType()->isVoidType()) {
 821       Result = 1;
 822       break;
 823     }
 824
 825     // alignof always evaluates to a constant, sizeof does if arg is not VLA.
 826     if (Exp->isSizeOf() && !Exp->getArgumentType()->isConstantSizeType()) {
 827       if (Loc) *Loc = Exp->getOperatorLoc();
 828       return false;
 829     }
 830
 831     // Get information about the size or align.
 832     if (Exp->getArgumentType()->isFunctionType()) {
 833       // GCC extension: sizeof(function) = 1.
 834       Result = Exp->isSizeOf() ? 1 : 4;
 835     } else {
 836       unsigned CharSize = Ctx.Target.getCharWidth();
 837       if (Exp->isSizeOf())
 838         Result = Ctx.getTypeSize(Exp->getArgumentType()) / CharSize;
 839       else
 840         Result = Ctx.getTypeAlign(Exp->getArgumentType()) / CharSize;
 841     }
 842     break;
 843   }
 844   case BinaryOperatorClass: {
 845     const BinaryOperator *Exp = cast<BinaryOperator>(this);
 846
 847     // The LHS of a constant expr is always evaluated and needed.
 848     if (!Exp->getLHS()->isIntegerConstantExpr(Result, Ctx, Loc, isEvaluated))
 849       return false;
 850
 851     llvm::APSInt RHS(Result);
 852
 853     // The short-circuiting &&/|| operators don't necessarily evaluate their
 854     // RHS.  Make sure to pass isEvaluated down correctly.
 855     if (Exp->isLogicalOp()) {
 856       bool RHSEval;
 857       if (Exp->getOpcode() == BinaryOperator::LAnd)
 858         RHSEval = Result != 0;
 859       else {
 860         assert(Exp->getOpcode() == BinaryOperator::LOr &&"Unexpected logical");
 861         RHSEval = Result == 0;
 862       }
 863
 864       if (!Exp->getRHS()->isIntegerConstantExpr(RHS, Ctx, Loc,
 865                                                 isEvaluated & RHSEval))
 866         return false;
 867     } else {
 868       if (!Exp->getRHS()->isIntegerConstantExpr(RHS, Ctx, Loc, isEvaluated))
 869         return false;
 870     }
 871
 872     switch (Exp->getOpcode()) {
 873     default:
 874       if (Loc) *Loc = getLocStart();
 875       return false;
 876     case BinaryOperator::Mul:
 877       Result *= RHS;
 878       break;
 879     case BinaryOperator::Div:
 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::Rem:
 888       if (RHS == 0) {
 889         if (!isEvaluated) break;
 890         if (Loc) *Loc = getLocStart();
 891         return false;
 892       }
 893       Result %= RHS;
 894       break;
 895     case BinaryOperator::Add: Result += RHS; break;
 896     case BinaryOperator::Sub: Result -= RHS; break;
 897     case BinaryOperator::Shl:
 898       Result <<=
 899         static_cast<uint32_t>(RHS.getLimitedValue(Result.getBitWidth()-1));
 900       break;
 901     case BinaryOperator::Shr:
 902       Result >>=
 903         static_cast<uint32_t>(RHS.getLimitedValue(Result.getBitWidth()-1));
 904       break;
 905     case BinaryOperator::LT:  Result = Result < RHS; break;
 906     case BinaryOperator::GT:  Result = Result > RHS; break;
 907     case BinaryOperator::LE:  Result = Result <= RHS; break;
 908     case BinaryOperator::GE:  Result = Result >= RHS; break;
 909     case BinaryOperator::EQ:  Result = Result == RHS; break;
 910     case BinaryOperator::NE:  Result = Result != RHS; break;
 911     case BinaryOperator::And: Result &= RHS; break;
 912     case BinaryOperator::Xor: Result ^= RHS; break;
 913     case BinaryOperator::Or:  Result |= RHS; break;
 914     case BinaryOperator::LAnd:
 915       Result = Result != 0 && RHS != 0;
 916       break;
 917     case BinaryOperator::LOr:
 918       Result = Result != 0 || RHS != 0;
 919       break;
 920
 921     case BinaryOperator::Comma:
 922       // C99 6.6p3: "shall not contain assignment, ..., or comma operators,
 923       // *except* when they are contained within a subexpression that is not
 924       // evaluated".  Note that Assignment can never happen due to constraints
 925       // on the LHS subexpr, so we don't need to check it here.
 926       if (isEvaluated) {
 927         if (Loc) *Loc = getLocStart();
 928         return false;
 929       }
 930
 931       // The result of the constant expr is the RHS.
 932       Result = RHS;
 933       return true;
 934     }
 935
 936     assert(!Exp->isAssignmentOp() && "LHS can't be a constant expr!");
 937     break;
 938   }
 939   case ImplicitCastExprClass:
 940   case ExplicitCastExprClass:
 941   case CXXFunctionalCastExprClass: {
 942     const Expr *SubExpr = cast<CastExpr>(this)->getSubExpr();
 943     SourceLocation CastLoc = getLocStart();
 944
 945     // C99 6.6p6: shall only convert arithmetic types to integer types.
 946     if (!SubExpr->getType()->isArithmeticType() ||
 947         !getType()->isIntegerType()) {
 948       if (Loc) *Loc = SubExpr->getLocStart();
 949       return false;
 950     }
 951
 952     uint32_t DestWidth = static_cast<uint32_t>(Ctx.getTypeSize(getType()));
 953
 954     // Handle simple integer->integer casts.
 955     if (SubExpr->getType()->isIntegerType()) {
 956       if (!SubExpr->isIntegerConstantExpr(Result, Ctx, Loc, isEvaluated))
 957         return false;
 958
 959       // Figure out if this is a truncate, extend or noop cast.
 960       // If the input is signed, do a sign extend, noop, or truncate.
 961       if (getType()->isBooleanType()) {
 962         // Conversion to bool compares against zero.
 963         Result = Result != 0;
 964         Result.zextOrTrunc(DestWidth);
 965       } else if (SubExpr->getType()->isSignedIntegerType())
 966         Result.sextOrTrunc(DestWidth);
 967       else  // If the input is unsigned, do a zero extend, noop, or truncate.
 968         Result.zextOrTrunc(DestWidth);
 969       break;
 970     }
 971
 972     // Allow floating constants that are the immediate operands of casts or that
 973     // are parenthesized.
 974     const Expr *Operand = SubExpr;
 975     while (const ParenExpr *PE = dyn_cast<ParenExpr>(Operand))
 976       Operand = PE->getSubExpr();
 977
 978     // If this isn't a floating literal, we can't handle it.
 979     const FloatingLiteral *FL = dyn_cast<FloatingLiteral>(Operand);
 980     if (!FL) {
 981       if (Loc) *Loc = Operand->getLocStart();
 982       return false;
 983     }
 984
 985     // If the destination is boolean, compare against zero.
 986     if (getType()->isBooleanType()) {
 987       Result = !FL->getValue().isZero();
 988       Result.zextOrTrunc(DestWidth);
 989       break;
 990     }
 991
 992     // Determine whether we are converting to unsigned or signed.
 993     bool DestSigned = getType()->isSignedIntegerType();
 994
 995     // TODO: Warn on overflow, but probably not here: isIntegerConstantExpr can
 996     // be called multiple times per AST.
 997     uint64_t Space[4];
 998     (void)FL->getValue().convertToInteger(Space, DestWidth, DestSigned,
 999                                           llvm::APFloat::rmTowardZero);
1000     Result = llvm::APInt(DestWidth, 4, Space);
1001     break;
1002   }
1003   case ConditionalOperatorClass: {
1004     const ConditionalOperator *Exp = cast<ConditionalOperator>(this);
1005
1006     if (!Exp->getCond()->isIntegerConstantExpr(Result, Ctx, Loc, isEvaluated))
1007       return false;
1008
1009     const Expr *TrueExp  = Exp->getLHS();
1010     const Expr *FalseExp = Exp->getRHS();
1011     if (Result == 0) std::swap(TrueExp, FalseExp);
1012
1013     // Evaluate the false one first, discard the result.
1014     if (FalseExp && !FalseExp->isIntegerConstantExpr(Result, Ctx, Loc, false))
1015       return false;
1016     // Evalute the true one, capture the result.
1017     if (TrueExp &&
1018         !TrueExp->isIntegerConstantExpr(Result, Ctx, Loc, isEvaluated))
1019       return false;
1020     break;
1021   }
1022   case CXXDefaultArgExprClass:
1023     return cast<CXXDefaultArgExpr>(this)
1024              ->isIntegerConstantExpr(Result, Ctx, Loc, isEvaluated);
1025   }
1026
1027   // Cases that are valid constant exprs fall through to here.
1028   Result.setIsUnsigned(getType()->isUnsignedIntegerType());
1029   return true;
1030 }
1031
1032 /// isNullPointerConstant - C99 6.3.2.3p3 -  Return true if this is either an
1033 /// integer constant expression with the value zero, or if this is one that is
1034 /// cast to void*.
1035 bool Expr::isNullPointerConstant(ASTContext &Ctx) const {
1036   // Strip off a cast to void*, if it exists.
1037   if (const ExplicitCastExpr *CE = dyn_cast<ExplicitCastExpr>(this)) {
1038     // Check that it is a cast to void*.
1039     if (const PointerType *PT = CE->getType()->getAsPointerType()) {
1040       QualType Pointee = PT->getPointeeType();
1041       if (Pointee.getCVRQualifiers() == 0 &&
1042           Pointee->isVoidType() &&                                 // to void*
1043           CE->getSubExpr()->getType()->isIntegerType())            // from int.
1044         return CE->getSubExpr()->isNullPointerConstant(Ctx);
1045     }
1046   } else if (const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(this)) {
1047     // Ignore the ImplicitCastExpr type entirely.
1048     return ICE->getSubExpr()->isNullPointerConstant(Ctx);
1049   } else if (const ParenExpr *PE = dyn_cast<ParenExpr>(this)) {
1050     // Accept ((void*)0) as a null pointer constant, as many other
1051     // implementations do.
1052     return PE->getSubExpr()->isNullPointerConstant(Ctx);
1053   } else if (const CXXDefaultArgExpr *DefaultArg
1054                = dyn_cast<CXXDefaultArgExpr>(this)) {
1055     // See through default argument expressions
1056     return DefaultArg->getExpr()->isNullPointerConstant(Ctx);
1057   }
1058
1059   // This expression must be an integer type.
1060   if (!getType()->isIntegerType())
1061     return false;
1062
1063   // If we have an integer constant expression, we need to *evaluate* it and
1064   // test for the value 0.
1065   llvm::APSInt Val(32);
1066   return isIntegerConstantExpr(Val, Ctx, 0, true) && Val == 0;
1067 }
1068
1069 unsigned ExtVectorElementExpr::getNumElements() const {
1070   if (const VectorType *VT = getType()->getAsVectorType())
1071     return VT->getNumElements();
1072   return 1;
1073 }
1074
1075 /// containsDuplicateElements - Return true if any element access is repeated.
1076 bool ExtVectorElementExpr::containsDuplicateElements() const {
1077   const char *compStr = Accessor.getName();
1078   unsigned length = strlen(compStr);
1079
1080   for (unsigned i = 0; i < length-1; i++) {
1081     const char *s = compStr+i;
1082     for (const char c = *s++; *s; s++)
1083       if (c == *s)
1084         return true;
1085   }
1086   return false;
1087 }
1088
1089 /// getEncodedElementAccess - We encode the fields as a llvm ConstantArray.
1090 void ExtVectorElementExpr::getEncodedElementAccess(
1091                                   llvm::SmallVectorImpl<unsigned> &Elts) const {
1092   const char *compStr = Accessor.getName();
1093
1094   bool isHi =   !strcmp(compStr, "hi");
1095   bool isLo =   !strcmp(compStr, "lo");
1096   bool isEven = !strcmp(compStr, "e");
1097   bool isOdd  = !strcmp(compStr, "o");
1098
1099   for (unsigned i = 0, e = getNumElements(); i != e; ++i) {
1100     uint64_t Index;
1101
1102     if (isHi)
1103       Index = e + i;
1104     else if (isLo)
1105       Index = i;
1106     else if (isEven)
1107       Index = 2 * i;
1108     else if (isOdd)
1109       Index = 2 * i + 1;
1110     else
1111       Index = ExtVectorType::getAccessorIdx(compStr[i]);
1112
1113     Elts.push_back(Index);
1114   }
1115 }
1116
1117 // constructor for instance messages.
1118 ObjCMessageExpr::ObjCMessageExpr(Expr *receiver, Selector selInfo,
1119                 QualType retType, ObjCMethodDecl *mproto,
1120                 SourceLocation LBrac, SourceLocation RBrac,
1121                 Expr **ArgExprs, unsigned nargs)
1122   : Expr(ObjCMessageExprClass, retType), SelName(selInfo),
1123     MethodProto(mproto) {
1124   NumArgs = nargs;
1125   SubExprs = new Stmt*[NumArgs+1];
1126   SubExprs[RECEIVER] = receiver;
1127   if (NumArgs) {
1128     for (unsigned i = 0; i != NumArgs; ++i)
1129       SubExprs[i+ARGS_START] = static_cast<Expr *>(ArgExprs[i]);
1130   }
1131   LBracloc = LBrac;
1132   RBracloc = RBrac;
1133 }
1134
1135 // constructor for class messages.
1136 // FIXME: clsName should be typed to ObjCInterfaceType
1137 ObjCMessageExpr::ObjCMessageExpr(IdentifierInfo *clsName, Selector selInfo,
1138                 QualType retType, ObjCMethodDecl *mproto,
1139                 SourceLocation LBrac, SourceLocation RBrac,
1140                 Expr **ArgExprs, unsigned nargs)
1141   : Expr(ObjCMessageExprClass, retType), SelName(selInfo),
1142     MethodProto(mproto) {
1143   NumArgs = nargs;
1144   SubExprs = new Stmt*[NumArgs+1];
1145   SubExprs[RECEIVER] = (Expr*) ((uintptr_t) clsName | IsClsMethDeclUnknown);
1146   if (NumArgs) {
1147     for (unsigned i = 0; i != NumArgs; ++i)
1148       SubExprs[i+ARGS_START] = static_cast<Expr *>(ArgExprs[i]);
1149   }
1150   LBracloc = LBrac;
1151   RBracloc = RBrac;
1152 }
1153
1154 // constructor for class messages.
1155 ObjCMessageExpr::ObjCMessageExpr(ObjCInterfaceDecl *cls, Selector selInfo,
1156                                  QualType retType, ObjCMethodDecl *mproto,
1157                                  SourceLocation LBrac, SourceLocation RBrac,
1158                                  Expr **ArgExprs, unsigned nargs)
1159 : Expr(ObjCMessageExprClass, retType), SelName(selInfo),
1160 MethodProto(mproto) {
1161   NumArgs = nargs;
1162   SubExprs = new Stmt*[NumArgs+1];
1163   SubExprs[RECEIVER] = (Expr*) ((uintptr_t) cls | IsClsMethDeclKnown);
1164   if (NumArgs) {
1165     for (unsigned i = 0; i != NumArgs; ++i)
1166       SubExprs[i+ARGS_START] = static_cast<Expr *>(ArgExprs[i]);
1167   }
1168   LBracloc = LBrac;
1169   RBracloc = RBrac;
1170 }
1171
1172 ObjCMessageExpr::ClassInfo ObjCMessageExpr::getClassInfo() const {
1173   uintptr_t x = (uintptr_t) SubExprs[RECEIVER];
1174   switch (x & Flags) {
1175     default:
1176       assert(false && "Invalid ObjCMessageExpr.");
1177     case IsInstMeth:
1178       return ClassInfo(0, 0);
1179     case IsClsMethDeclUnknown:
1180       return ClassInfo(0, (IdentifierInfo*) (x & ~Flags));
1181     case IsClsMethDeclKnown: {
1182       ObjCInterfaceDecl* D = (ObjCInterfaceDecl*) (x & ~Flags);
1183       return ClassInfo(D, D->getIdentifier());
1184     }
1185   }
1186 }
1187
1188 bool ChooseExpr::isConditionTrue(ASTContext &C) const {
1189   return getCond()->getIntegerConstantExprValue(C) != 0;
1190 }
1191
1192 static int64_t evaluateOffsetOf(ASTContext& C, const Expr *E)
1193 {
1194   if (const MemberExpr *ME = dyn_cast<MemberExpr>(E)) {
1195     QualType Ty = ME->getBase()->getType();
1196
1197     RecordDecl *RD = Ty->getAsRecordType()->getDecl();
1198     const ASTRecordLayout &RL = C.getASTRecordLayout(RD);
1199     FieldDecl *FD = ME->getMemberDecl();
1200
1201     // FIXME: This is linear time.
1202     unsigned i = 0, e = 0;
1203     for (i = 0, e = RD->getNumMembers(); i != e; i++) {
1204       if (RD->getMember(i) == FD)
1205         break;
1206     }
1207
1208     return RL.getFieldOffset(i) + evaluateOffsetOf(C, ME->getBase());
1209   } else if (const ArraySubscriptExpr *ASE = dyn_cast<ArraySubscriptExpr>(E)) {
1210     const Expr *Base = ASE->getBase();
1211
1212     int64_t size = C.getTypeSize(ASE->getType());
1213     size *= ASE->getIdx()->getIntegerConstantExprValue(C).getSExtValue();
1214
1215     return size + evaluateOffsetOf(C, Base);
1216   } else if (isa<CompoundLiteralExpr>(E))
1217     return 0;
1218
1219   assert(0 && "Unknown offsetof subexpression!");
1220   return 0;
1221 }
1222
1223 int64_t UnaryOperator::evaluateOffsetOf(ASTContext& C) const
1224 {
1225   assert(Opc == OffsetOf && "Unary operator not offsetof!");
1226
1227   unsigned CharSize = C.Target.getCharWidth();
1228   return ::evaluateOffsetOf(C, cast<Expr>(Val)) / CharSize;
1229 }
1230
1231 //===----------------------------------------------------------------------===//
1232 //  Child Iterators for iterating over subexpressions/substatements
1233 //===----------------------------------------------------------------------===//
1234
1235 // DeclRefExpr
1236 Stmt::child_iterator DeclRefExpr::child_begin() { return child_iterator(); }
1237 Stmt::child_iterator DeclRefExpr::child_end() { return child_iterator(); }
1238
1239 // ObjCIvarRefExpr
1240 Stmt::child_iterator ObjCIvarRefExpr::child_begin() { return &Base; }
1241 Stmt::child_iterator ObjCIvarRefExpr::child_end() { return &Base+1; }
1242
1243 // ObjCPropertyRefExpr
1244 Stmt::child_iterator ObjCPropertyRefExpr::child_begin() { return &Base; }
1245 Stmt::child_iterator ObjCPropertyRefExpr::child_end() { return &Base+1; }
1246
1247 // PredefinedExpr
1248 Stmt::child_iterator PredefinedExpr::child_begin() { return child_iterator(); }
1249 Stmt::child_iterator PredefinedExpr::child_end() { return child_iterator(); }
1250
1251 // IntegerLiteral
1252 Stmt::child_iterator IntegerLiteral::child_begin() { return child_iterator(); }
1253 Stmt::child_iterator IntegerLiteral::child_end() { return child_iterator(); }
1254
1255 // CharacterLiteral
1256 Stmt::child_iterator CharacterLiteral::child_begin() { return child_iterator(); }
1257 Stmt::child_iterator CharacterLiteral::child_end() { return child_iterator(); }
1258
1259 // FloatingLiteral
1260 Stmt::child_iterator FloatingLiteral::child_begin() { return child_iterator(); }
1261 Stmt::child_iterator FloatingLiteral::child_end() { return child_iterator(); }
1262
1263 // ImaginaryLiteral
1264 Stmt::child_iterator ImaginaryLiteral::child_begin() { return &Val; }
1265 Stmt::child_iterator ImaginaryLiteral::child_end() { return &Val+1; }
1266
1267 // StringLiteral
1268 Stmt::child_iterator StringLiteral::child_begin() { return child_iterator(); }
1269 Stmt::child_iterator StringLiteral::child_end() { return child_iterator(); }
1270
1271 // ParenExpr
1272 Stmt::child_iterator ParenExpr::child_begin() { return &Val; }
1273 Stmt::child_iterator ParenExpr::child_end() { return &Val+1; }
1274
1275 // UnaryOperator
1276 Stmt::child_iterator UnaryOperator::child_begin() { return &Val; }
1277 Stmt::child_iterator UnaryOperator::child_end() { return &Val+1; }
1278
1279 // SizeOfAlignOfTypeExpr
1280 Stmt::child_iterator SizeOfAlignOfTypeExpr::child_begin() {
1281   // If the type is a VLA type (and not a typedef), the size expression of the
1282   // VLA needs to be treated as an executable expression.
1283   if (VariableArrayType* T = dyn_cast<VariableArrayType>(Ty.getTypePtr()))
1284     return child_iterator(T);
1285   else
1286     return child_iterator();
1287 }
1288 Stmt::child_iterator SizeOfAlignOfTypeExpr::child_end() {
1289   return child_iterator();
1290 }
1291
1292 // ArraySubscriptExpr
1293 Stmt::child_iterator ArraySubscriptExpr::child_begin() {
1294   return &SubExprs[0];
1295 }
1296 Stmt::child_iterator ArraySubscriptExpr::child_end() {
1297   return &SubExprs[0]+END_EXPR;
1298 }
1299
1300 // CallExpr
1301 Stmt::child_iterator CallExpr::child_begin() {
1302   return &SubExprs[0];
1303 }
1304 Stmt::child_iterator CallExpr::child_end() {
1305   return &SubExprs[0]+NumArgs+ARGS_START;
1306 }
1307
1308 // MemberExpr
1309 Stmt::child_iterator MemberExpr::child_begin() { return &Base; }
1310 Stmt::child_iterator MemberExpr::child_end() { return &Base+1; }
1311
1312 // ExtVectorElementExpr
1313 Stmt::child_iterator ExtVectorElementExpr::child_begin() { return &Base; }
1314 Stmt::child_iterator ExtVectorElementExpr::child_end() { return &Base+1; }
1315
1316 // CompoundLiteralExpr
1317 Stmt::child_iterator CompoundLiteralExpr::child_begin() { return &Init; }
1318 Stmt::child_iterator CompoundLiteralExpr::child_end() { return &Init+1; }
1319
1320 // CastExpr
1321 Stmt::child_iterator CastExpr::child_begin() { return &Op; }
1322 Stmt::child_iterator CastExpr::child_end() { return &Op+1; }
1323
1324 // BinaryOperator
1325 Stmt::child_iterator BinaryOperator::child_begin() {
1326   return &SubExprs[0];
1327 }
1328 Stmt::child_iterator BinaryOperator::child_end() {
1329   return &SubExprs[0]+END_EXPR;
1330 }
1331
1332 // ConditionalOperator
1333 Stmt::child_iterator ConditionalOperator::child_begin() {
1334   return &SubExprs[0];
1335 }
1336 Stmt::child_iterator ConditionalOperator::child_end() {
1337   return &SubExprs[0]+END_EXPR;
1338 }
1339
1340 // AddrLabelExpr
1341 Stmt::child_iterator AddrLabelExpr::child_begin() { return child_iterator(); }
1342 Stmt::child_iterator AddrLabelExpr::child_end() { return child_iterator(); }
1343
1344 // StmtExpr
1345 Stmt::child_iterator StmtExpr::child_begin() { return &SubStmt; }
1346 Stmt::child_iterator StmtExpr::child_end() { return &SubStmt+1; }
1347
1348 // TypesCompatibleExpr
1349 Stmt::child_iterator TypesCompatibleExpr::child_begin() {
1350   return child_iterator();
1351 }
1352
1353 Stmt::child_iterator TypesCompatibleExpr::child_end() {
1354   return child_iterator();
1355 }
1356
1357 // ChooseExpr
1358 Stmt::child_iterator ChooseExpr::child_begin() { return &SubExprs[0]; }
1359 Stmt::child_iterator ChooseExpr::child_end() { return &SubExprs[0]+END_EXPR; }
1360
1361 // OverloadExpr
1362 Stmt::child_iterator OverloadExpr::child_begin() { return &SubExprs[0]; }
1363 Stmt::child_iterator OverloadExpr::child_end() { return &SubExprs[0]+NumExprs; }
1364
1365 // ShuffleVectorExpr
1366 Stmt::child_iterator ShuffleVectorExpr::child_begin() {
1367   return &SubExprs[0];
1368 }
1369 Stmt::child_iterator ShuffleVectorExpr::child_end() {
1370   return &SubExprs[0]+NumExprs;
1371 }
1372
1373 // VAArgExpr
1374 Stmt::child_iterator VAArgExpr::child_begin() { return &Val; }
1375 Stmt::child_iterator VAArgExpr::child_end() { return &Val+1; }
1376
1377 // InitListExpr
1378 Stmt::child_iterator InitListExpr::child_begin() {
1379   return InitExprs.size() ? &InitExprs[0] : 0;
1380 }
1381 Stmt::child_iterator InitListExpr::child_end() {
1382   return InitExprs.size() ? &InitExprs[0] + InitExprs.size() : 0;
1383 }
1384
1385 // ObjCStringLiteral
1386 Stmt::child_iterator ObjCStringLiteral::child_begin() {
1387   return child_iterator();
1388 }
1389 Stmt::child_iterator ObjCStringLiteral::child_end() {
1390   return child_iterator();
1391 }
1392
1393 // ObjCEncodeExpr
1394 Stmt::child_iterator ObjCEncodeExpr::child_begin() { return child_iterator(); }
1395 Stmt::child_iterator ObjCEncodeExpr::child_end() { return child_iterator(); }
1396
1397 // ObjCSelectorExpr
1398 Stmt::child_iterator ObjCSelectorExpr::child_begin() {
1399   return child_iterator();
1400 }
1401 Stmt::child_iterator ObjCSelectorExpr::child_end() {
1402   return child_iterator();
1403 }
1404
1405 // ObjCProtocolExpr
1406 Stmt::child_iterator ObjCProtocolExpr::child_begin() {
1407   return child_iterator();
1408 }
1409 Stmt::child_iterator ObjCProtocolExpr::child_end() {
1410   return child_iterator();
1411 }
1412
1413 // ObjCMessageExpr
1414 Stmt::child_iterator ObjCMessageExpr::child_begin() {
1415   return getReceiver() ? &SubExprs[0] : &SubExprs[0] + ARGS_START;
1416 }
1417 Stmt::child_iterator ObjCMessageExpr::child_end() {
1418   return &SubExprs[0]+ARGS_START+getNumArgs();
1419 }
1420