SemaExprCXX.cpp revision d5a949898d4547babb07823bae45ed8324bef9de 
1//===--- SemaExprCXX.cpp - Semantic Analysis for Expressions --------------===//
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 semantic analysis for C++ expressions.
11//
12//===----------------------------------------------------------------------===//
13
14#include "SemaInherit.h"
15#include "Sema.h"
16#include "clang/AST/ExprCXX.h"
17#include "clang/AST/ASTContext.h"
18#include "clang/Parse/DeclSpec.h"
19#include "clang/Lex/Preprocessor.h"
20#include "clang/Basic/TargetInfo.h"
21#include "llvm/ADT/STLExtras.h"
22using namespace clang;
23
24/// ActOnCXXConversionFunctionExpr - Parse a C++ conversion function
25/// name (e.g., operator void const *) as an expression. This is
26/// very similar to ActOnIdentifierExpr, except that instead of
27/// providing an identifier the parser provides the type of the
28/// conversion function.
29Sema::OwningExprResult
30Sema::ActOnCXXConversionFunctionExpr(Scope *S, SourceLocation OperatorLoc,
31                                     TypeTy *Ty, bool HasTrailingLParen,
32                                     const CXXScopeSpec &SS,
33                                     bool isAddressOfOperand) {
34  QualType ConvType = QualType::getFromOpaquePtr(Ty);
35  QualType ConvTypeCanon = Context.getCanonicalType(ConvType);
36  DeclarationName ConvName
37    = Context.DeclarationNames.getCXXConversionFunctionName(ConvTypeCanon);
38  return ActOnDeclarationNameExpr(S, OperatorLoc, ConvName, HasTrailingLParen,
39                                  &SS, isAddressOfOperand);
40}
41
42/// ActOnCXXOperatorFunctionIdExpr - Parse a C++ overloaded operator
43/// name (e.g., @c operator+ ) as an expression. This is very
44/// similar to ActOnIdentifierExpr, except that instead of providing
45/// an identifier the parser provides the kind of overloaded
46/// operator that was parsed.
47Sema::OwningExprResult
48Sema::ActOnCXXOperatorFunctionIdExpr(Scope *S, SourceLocation OperatorLoc,
49                                     OverloadedOperatorKind Op,
50                                     bool HasTrailingLParen,
51                                     const CXXScopeSpec &SS,
52                                     bool isAddressOfOperand) {
53  DeclarationName Name = Context.DeclarationNames.getCXXOperatorName(Op);
54  return ActOnDeclarationNameExpr(S, OperatorLoc, Name, HasTrailingLParen, &SS,
55                                  isAddressOfOperand);
56}
57
58/// ActOnCXXTypeidOfType - Parse typeid( type-id ).
59Action::OwningExprResult
60Sema::ActOnCXXTypeid(SourceLocation OpLoc, SourceLocation LParenLoc,
61                     bool isType, void *TyOrExpr, SourceLocation RParenLoc) {
62  NamespaceDecl *StdNs = GetStdNamespace();
63  if (!StdNs)
64    return ExprError(Diag(OpLoc, diag::err_need_header_before_typeid));
65
66  IdentifierInfo *TypeInfoII = &PP.getIdentifierTable().get("type_info");
67  Decl *TypeInfoDecl = LookupQualifiedName(StdNs, TypeInfoII, LookupTagName);
68  RecordDecl *TypeInfoRecordDecl = dyn_cast_or_null<RecordDecl>(TypeInfoDecl);
69  if (!TypeInfoRecordDecl)
70    return ExprError(Diag(OpLoc, diag::err_need_header_before_typeid));
71
72  QualType TypeInfoType = Context.getTypeDeclType(TypeInfoRecordDecl);
73
74  return Owned(new (Context) CXXTypeidExpr(isType, TyOrExpr,
75                                           TypeInfoType.withConst(),
76                                           SourceRange(OpLoc, RParenLoc)));
77}
78
79/// ActOnCXXBoolLiteral - Parse {true,false} literals.
80Action::OwningExprResult
81Sema::ActOnCXXBoolLiteral(SourceLocation OpLoc, tok::TokenKind Kind) {
82  assert((Kind == tok::kw_true || Kind == tok::kw_false) &&
83         "Unknown C++ Boolean value!");
84  return Owned(new (Context) CXXBoolLiteralExpr(Kind == tok::kw_true,
85                                                Context.BoolTy, OpLoc));
86}
87
88/// ActOnCXXThrow - Parse throw expressions.
89Action::OwningExprResult
90Sema::ActOnCXXThrow(SourceLocation OpLoc, ExprArg E) {
91  return Owned(new (Context) CXXThrowExpr((Expr*)E.release(), Context.VoidTy,
92                                          OpLoc));
93}
94
95Action::OwningExprResult Sema::ActOnCXXThis(SourceLocation ThisLoc) {
96  /// C++ 9.3.2: In the body of a non-static member function, the keyword this
97  /// is a non-lvalue expression whose value is the address of the object for
98  /// which the function is called.
99
100  if (!isa<FunctionDecl>(CurContext))
101    return ExprError(Diag(ThisLoc, diag::err_invalid_this_use));
102
103  if (CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(CurContext))
104    if (MD->isInstance())
105      return Owned(new (Context) CXXThisExpr(ThisLoc,
106                                             MD->getThisType(Context)));
107
108  return ExprError(Diag(ThisLoc, diag::err_invalid_this_use));
109}
110
111/// ActOnCXXTypeConstructExpr - Parse construction of a specified type.
112/// Can be interpreted either as function-style casting ("int(x)")
113/// or class type construction ("ClassType(x,y,z)")
114/// or creation of a value-initialized type ("int()").
115Action::OwningExprResult
116Sema::ActOnCXXTypeConstructExpr(SourceRange TypeRange, TypeTy *TypeRep,
117                                SourceLocation LParenLoc,
118                                MultiExprArg exprs,
119                                SourceLocation *CommaLocs,
120                                SourceLocation RParenLoc) {
121  assert(TypeRep && "Missing type!");
122  QualType Ty = QualType::getFromOpaquePtr(TypeRep);
123  unsigned NumExprs = exprs.size();
124  Expr **Exprs = (Expr**)exprs.get();
125  SourceLocation TyBeginLoc = TypeRange.getBegin();
126  SourceRange FullRange = SourceRange(TyBeginLoc, RParenLoc);
127
128  if (Ty->isDependentType() ||
129      CallExpr::hasAnyTypeDependentArguments(Exprs, NumExprs)) {
130    exprs.release();
131    return Owned(new (Context) CXXTemporaryObjectExpr(0, Ty, TyBeginLoc,
132                                                      Exprs, NumExprs,
133                                                      RParenLoc));
134  }
135
136
137  // C++ [expr.type.conv]p1:
138  // If the expression list is a single expression, the type conversion
139  // expression is equivalent (in definedness, and if defined in meaning) to the
140  // corresponding cast expression.
141  //
142  if (NumExprs == 1) {
143    if (CheckCastTypes(TypeRange, Ty, Exprs[0]))
144      return ExprError();
145    exprs.release();
146    return Owned(new (Context) CXXFunctionalCastExpr(Ty.getNonReferenceType(),
147                                                     Ty, TyBeginLoc, Exprs[0],
148                                                     RParenLoc));
149  }
150
151  if (const RecordType *RT = Ty->getAsRecordType()) {
152    CXXRecordDecl *Record = cast<CXXRecordDecl>(RT->getDecl());
153
154    if (NumExprs > 1 || Record->hasUserDeclaredConstructor()) {
155      CXXConstructorDecl *Constructor
156        = PerformInitializationByConstructor(Ty, Exprs, NumExprs,
157                                             TypeRange.getBegin(),
158                                             SourceRange(TypeRange.getBegin(),
159                                                         RParenLoc),
160                                             DeclarationName(),
161                                             IK_Direct);
162
163      if (!Constructor)
164        return ExprError();
165
166      exprs.release();
167      return Owned(new (Context) CXXTemporaryObjectExpr(Constructor, Ty,
168                                                        TyBeginLoc,  Exprs,
169                                                        NumExprs, RParenLoc));
170    }
171
172    // Fall through to value-initialize an object of class type that
173    // doesn't have a user-declared default constructor.
174  }
175
176  // C++ [expr.type.conv]p1:
177  // If the expression list specifies more than a single value, the type shall
178  // be a class with a suitably declared constructor.
179  //
180  if (NumExprs > 1)
181    return ExprError(Diag(CommaLocs[0],
182                          diag::err_builtin_func_cast_more_than_one_arg)
183      << FullRange);
184
185  assert(NumExprs == 0 && "Expected 0 expressions");
186
187  // C++ [expr.type.conv]p2:
188  // The expression T(), where T is a simple-type-specifier for a non-array
189  // complete object type or the (possibly cv-qualified) void type, creates an
190  // rvalue of the specified type, which is value-initialized.
191  //
192  if (Ty->isArrayType())
193    return ExprError(Diag(TyBeginLoc,
194                          diag::err_value_init_for_array_type) << FullRange);
195  if (!Ty->isDependentType() && !Ty->isVoidType() &&
196      RequireCompleteType(TyBeginLoc, Ty,
197                          diag::err_invalid_incomplete_type_use, FullRange))
198    return ExprError();
199
200  exprs.release();
201  return Owned(new (Context) CXXZeroInitValueExpr(Ty, TyBeginLoc, RParenLoc));
202}
203
204
205/// ActOnCXXNew - Parsed a C++ 'new' expression (C++ 5.3.4), as in e.g.:
206/// @code new (memory) int[size][4] @endcode
207/// or
208/// @code ::new Foo(23, "hello") @endcode
209/// For the interpretation of this heap of arguments, consult the base version.
210Action::OwningExprResult
211Sema::ActOnCXXNew(SourceLocation StartLoc, bool UseGlobal,
212                  SourceLocation PlacementLParen, MultiExprArg PlacementArgs,
213                  SourceLocation PlacementRParen, bool ParenTypeId,
214                  Declarator &D, SourceLocation ConstructorLParen,
215                  MultiExprArg ConstructorArgs,
216                  SourceLocation ConstructorRParen)
217{
218  Expr *ArraySize = 0;
219  unsigned Skip = 0;
220  // If the specified type is an array, unwrap it and save the expression.
221  if (D.getNumTypeObjects() > 0 &&
222      D.getTypeObject(0).Kind == DeclaratorChunk::Array) {
223    DeclaratorChunk &Chunk = D.getTypeObject(0);
224    if (Chunk.Arr.hasStatic)
225      return ExprError(Diag(Chunk.Loc, diag::err_static_illegal_in_new)
226        << D.getSourceRange());
227    if (!Chunk.Arr.NumElts)
228      return ExprError(Diag(Chunk.Loc, diag::err_array_new_needs_size)
229        << D.getSourceRange());
230    ArraySize = static_cast<Expr*>(Chunk.Arr.NumElts);
231    Skip = 1;
232  }
233
234  QualType AllocType = GetTypeForDeclarator(D, /*Scope=*/0, Skip);
235  if (D.getInvalidType())
236    return ExprError();
237
238  if (CheckAllocatedType(AllocType, D))
239    return ExprError();
240
241  if (RequireNonAbstractType(D.getSourceRange().getBegin(), AllocType,
242                             diag::err_allocation_of_abstract_type, 0))
243    return ExprError();
244
245  QualType ResultType = AllocType->isDependentType()
246                          ? Context.DependentTy
247                          : Context.getPointerType(AllocType);
248
249  // That every array dimension except the first is constant was already
250  // checked by the type check above.
251
252  // C++ 5.3.4p6: "The expression in a direct-new-declarator shall have integral
253  //   or enumeration type with a non-negative value."
254  if (ArraySize && !ArraySize->isTypeDependent()) {
255    QualType SizeType = ArraySize->getType();
256    if (!SizeType->isIntegralType() && !SizeType->isEnumeralType())
257      return ExprError(Diag(ArraySize->getSourceRange().getBegin(),
258                            diag::err_array_size_not_integral)
259        << SizeType << ArraySize->getSourceRange());
260    // Let's see if this is a constant < 0. If so, we reject it out of hand.
261    // We don't care about special rules, so we tell the machinery it's not
262    // evaluated - it gives us a result in more cases.
263    if (!ArraySize->isValueDependent()) {
264      llvm::APSInt Value;
265      if (ArraySize->isIntegerConstantExpr(Value, Context, 0, false)) {
266        if (Value < llvm::APSInt(
267                        llvm::APInt::getNullValue(Value.getBitWidth()), false))
268          return ExprError(Diag(ArraySize->getSourceRange().getBegin(),
269                           diag::err_typecheck_negative_array_size)
270            << ArraySize->getSourceRange());
271      }
272    }
273  }
274
275  FunctionDecl *OperatorNew = 0;
276  FunctionDecl *OperatorDelete = 0;
277  Expr **PlaceArgs = (Expr**)PlacementArgs.get();
278  unsigned NumPlaceArgs = PlacementArgs.size();
279  if (!AllocType->isDependentType() &&
280      !Expr::hasAnyTypeDependentArguments(PlaceArgs, NumPlaceArgs) &&
281      FindAllocationFunctions(StartLoc,
282                              SourceRange(PlacementLParen, PlacementRParen),
283                              UseGlobal, AllocType, ArraySize, PlaceArgs,
284                              NumPlaceArgs, OperatorNew, OperatorDelete))
285    return ExprError();
286
287  bool Init = ConstructorLParen.isValid();
288  // --- Choosing a constructor ---
289  // C++ 5.3.4p15
290  // 1) If T is a POD and there's no initializer (ConstructorLParen is invalid)
291  //   the object is not initialized. If the object, or any part of it, is
292  //   const-qualified, it's an error.
293  // 2) If T is a POD and there's an empty initializer, the object is value-
294  //   initialized.
295  // 3) If T is a POD and there's one initializer argument, the object is copy-
296  //   constructed.
297  // 4) If T is a POD and there's more initializer arguments, it's an error.
298  // 5) If T is not a POD, the initializer arguments are used as constructor
299  //   arguments.
300  //
301  // Or by the C++0x formulation:
302  // 1) If there's no initializer, the object is default-initialized according
303  //    to C++0x rules.
304  // 2) Otherwise, the object is direct-initialized.
305  CXXConstructorDecl *Constructor = 0;
306  Expr **ConsArgs = (Expr**)ConstructorArgs.get();
307  unsigned NumConsArgs = ConstructorArgs.size();
308  if (AllocType->isDependentType()) {
309    // Skip all the checks.
310  }
311  // FIXME: Should check for primitive/aggregate here, not record.
312  else if (const RecordType *RT = AllocType->getAsRecordType()) {
313    // FIXME: This is incorrect for when there is an empty initializer and
314    // no user-defined constructor. Must zero-initialize, not default-construct.
315    Constructor = PerformInitializationByConstructor(
316                      AllocType, ConsArgs, NumConsArgs,
317                      D.getSourceRange().getBegin(),
318                      SourceRange(D.getSourceRange().getBegin(),
319                                  ConstructorRParen),
320                      RT->getDecl()->getDeclName(),
321                      NumConsArgs != 0 ? IK_Direct : IK_Default);
322    if (!Constructor)
323      return ExprError();
324  } else {
325    if (!Init) {
326      // FIXME: Check that no subpart is const.
327      if (AllocType.isConstQualified())
328        return ExprError(Diag(StartLoc, diag::err_new_uninitialized_const)
329          << D.getSourceRange());
330    } else if (NumConsArgs == 0) {
331      // Object is value-initialized. Do nothing.
332    } else if (NumConsArgs == 1) {
333      // Object is direct-initialized.
334      // FIXME: WHAT DeclarationName do we pass in here?
335      if (CheckInitializerTypes(ConsArgs[0], AllocType, StartLoc,
336                                DeclarationName() /*AllocType.getAsString()*/,
337                                /*DirectInit=*/true))
338        return ExprError();
339    } else {
340      return ExprError(Diag(StartLoc,
341                            diag::err_builtin_direct_init_more_than_one_arg)
342        << SourceRange(ConstructorLParen, ConstructorRParen));
343    }
344  }
345
346  // FIXME: Also check that the destructor is accessible. (C++ 5.3.4p16)
347
348  PlacementArgs.release();
349  ConstructorArgs.release();
350  return Owned(new (Context) CXXNewExpr(UseGlobal, OperatorNew, PlaceArgs,
351                        NumPlaceArgs, ParenTypeId, ArraySize, Constructor, Init,
352                        ConsArgs, NumConsArgs, OperatorDelete, ResultType,
353                        StartLoc, Init ? ConstructorRParen : SourceLocation()));
354}
355
356/// CheckAllocatedType - Checks that a type is suitable as the allocated type
357/// in a new-expression.
358/// dimension off and stores the size expression in ArraySize.
359bool Sema::CheckAllocatedType(QualType AllocType, const Declarator &D)
360{
361  // C++ 5.3.4p1: "[The] type shall be a complete object type, but not an
362  //   abstract class type or array thereof.
363  // FIXME: We don't have abstract types yet.
364  // FIXME: Under C++ semantics, an incomplete object type is still an object
365  // type. This code assumes the C semantics, where it's not.
366  if (!AllocType->isObjectType()) {
367    unsigned type; // For the select in the message.
368    if (AllocType->isFunctionType()) {
369      type = 0;
370    } else if(AllocType->isIncompleteType()) {
371      type = 1;
372    } else {
373      assert(AllocType->isReferenceType() && "Unhandled non-object type.");
374      type = 2;
375    }
376    Diag(D.getSourceRange().getBegin(), diag::err_bad_new_type)
377      << AllocType << type << D.getSourceRange();
378    return true;
379  }
380
381  // Every dimension shall be of constant size.
382  unsigned i = 1;
383  while (const ArrayType *Array = Context.getAsArrayType(AllocType)) {
384    if (!Array->isConstantArrayType()) {
385      Diag(D.getTypeObject(i).Loc, diag::err_new_array_nonconst)
386        << static_cast<Expr*>(D.getTypeObject(i).Arr.NumElts)->getSourceRange();
387      return true;
388    }
389    AllocType = Array->getElementType();
390    ++i;
391  }
392
393  return false;
394}
395
396/// FindAllocationFunctions - Finds the overloads of operator new and delete
397/// that are appropriate for the allocation.
398bool Sema::FindAllocationFunctions(SourceLocation StartLoc, SourceRange Range,
399                                   bool UseGlobal, QualType AllocType,
400                                   bool IsArray, Expr **PlaceArgs,
401                                   unsigned NumPlaceArgs,
402                                   FunctionDecl *&OperatorNew,
403                                   FunctionDecl *&OperatorDelete)
404{
405  // --- Choosing an allocation function ---
406  // C++ 5.3.4p8 - 14 & 18
407  // 1) If UseGlobal is true, only look in the global scope. Else, also look
408  //   in the scope of the allocated class.
409  // 2) If an array size is given, look for operator new[], else look for
410  //   operator new.
411  // 3) The first argument is always size_t. Append the arguments from the
412  //   placement form.
413  // FIXME: Also find the appropriate delete operator.
414
415  llvm::SmallVector<Expr*, 8> AllocArgs(1 + NumPlaceArgs);
416  // We don't care about the actual value of this argument.
417  // FIXME: Should the Sema create the expression and embed it in the syntax
418  // tree? Or should the consumer just recalculate the value?
419  AllocArgs[0] = new (Context) IntegerLiteral(llvm::APInt::getNullValue(
420                                        Context.Target.getPointerWidth(0)),
421                                    Context.getSizeType(),
422                                    SourceLocation());
423  std::copy(PlaceArgs, PlaceArgs + NumPlaceArgs, AllocArgs.begin() + 1);
424
425  DeclarationName NewName = Context.DeclarationNames.getCXXOperatorName(
426                                        IsArray ? OO_Array_New : OO_New);
427  if (AllocType->isRecordType() && !UseGlobal) {
428    CXXRecordDecl *Record
429      = cast<CXXRecordDecl>(AllocType->getAsRecordType()->getDecl());
430    // FIXME: We fail to find inherited overloads.
431    if (FindAllocationOverload(StartLoc, Range, NewName, &AllocArgs[0],
432                          AllocArgs.size(), Record, /*AllowMissing=*/true,
433                          OperatorNew))
434      return true;
435  }
436  if (!OperatorNew) {
437    // Didn't find a member overload. Look for a global one.
438    DeclareGlobalNewDelete();
439    DeclContext *TUDecl = Context.getTranslationUnitDecl();
440    if (FindAllocationOverload(StartLoc, Range, NewName, &AllocArgs[0],
441                          AllocArgs.size(), TUDecl, /*AllowMissing=*/false,
442                          OperatorNew))
443      return true;
444  }
445
446  // FIXME: This is leaked on error. But so much is currently in Sema that it's
447  // easier to clean it in one go.
448  AllocArgs[0]->Destroy(Context);
449  return false;
450}
451
452/// FindAllocationOverload - Find an fitting overload for the allocation
453/// function in the specified scope.
454bool Sema::FindAllocationOverload(SourceLocation StartLoc, SourceRange Range,
455                                  DeclarationName Name, Expr** Args,
456                                  unsigned NumArgs, DeclContext *Ctx,
457                                  bool AllowMissing, FunctionDecl *&Operator)
458{
459  DeclContext::lookup_iterator Alloc, AllocEnd;
460  llvm::tie(Alloc, AllocEnd) = Ctx->lookup(Name);
461  if (Alloc == AllocEnd) {
462    if (AllowMissing)
463      return false;
464    return Diag(StartLoc, diag::err_ovl_no_viable_function_in_call)
465      << Name << Range;
466  }
467
468  OverloadCandidateSet Candidates;
469  for (; Alloc != AllocEnd; ++Alloc) {
470    // Even member operator new/delete are implicitly treated as
471    // static, so don't use AddMemberCandidate.
472    if (FunctionDecl *Fn = dyn_cast<FunctionDecl>(*Alloc))
473      AddOverloadCandidate(Fn, Args, NumArgs, Candidates,
474                           /*SuppressUserConversions=*/false);
475  }
476
477  // Do the resolution.
478  OverloadCandidateSet::iterator Best;
479  switch(BestViableFunction(Candidates, Best)) {
480  case OR_Success: {
481    // Got one!
482    FunctionDecl *FnDecl = Best->Function;
483    // The first argument is size_t, and the first parameter must be size_t,
484    // too. This is checked on declaration and can be assumed. (It can't be
485    // asserted on, though, since invalid decls are left in there.)
486    for (unsigned i = 1; i < NumArgs; ++i) {
487      // FIXME: Passing word to diagnostic.
488      if (PerformCopyInitialization(Args[i-1],
489                                    FnDecl->getParamDecl(i)->getType(),
490                                    "passing"))
491        return true;
492    }
493    Operator = FnDecl;
494    return false;
495  }
496
497  case OR_No_Viable_Function:
498    if (AllowMissing)
499      return false;
500    Diag(StartLoc, diag::err_ovl_no_viable_function_in_call)
501      << Name << Range;
502    PrintOverloadCandidates(Candidates, /*OnlyViable=*/false);
503    return true;
504
505  case OR_Ambiguous:
506    Diag(StartLoc, diag::err_ovl_ambiguous_call)
507      << Name << Range;
508    PrintOverloadCandidates(Candidates, /*OnlyViable=*/true);
509    return true;
510
511  case OR_Deleted:
512    Diag(StartLoc, diag::err_ovl_deleted_call)
513      << Best->Function->isDeleted()
514      << Name << Range;
515    PrintOverloadCandidates(Candidates, /*OnlyViable=*/true);
516    return true;
517  }
518  assert(false && "Unreachable, bad result from BestViableFunction");
519  return true;
520}
521
522
523/// DeclareGlobalNewDelete - Declare the global forms of operator new and
524/// delete. These are:
525/// @code
526///   void* operator new(std::size_t) throw(std::bad_alloc);
527///   void* operator new[](std::size_t) throw(std::bad_alloc);
528///   void operator delete(void *) throw();
529///   void operator delete[](void *) throw();
530/// @endcode
531/// Note that the placement and nothrow forms of new are *not* implicitly
532/// declared. Their use requires including \<new\>.
533void Sema::DeclareGlobalNewDelete()
534{
535  if (GlobalNewDeleteDeclared)
536    return;
537  GlobalNewDeleteDeclared = true;
538
539  QualType VoidPtr = Context.getPointerType(Context.VoidTy);
540  QualType SizeT = Context.getSizeType();
541
542  // FIXME: Exception specifications are not added.
543  DeclareGlobalAllocationFunction(
544      Context.DeclarationNames.getCXXOperatorName(OO_New),
545      VoidPtr, SizeT);
546  DeclareGlobalAllocationFunction(
547      Context.DeclarationNames.getCXXOperatorName(OO_Array_New),
548      VoidPtr, SizeT);
549  DeclareGlobalAllocationFunction(
550      Context.DeclarationNames.getCXXOperatorName(OO_Delete),
551      Context.VoidTy, VoidPtr);
552  DeclareGlobalAllocationFunction(
553      Context.DeclarationNames.getCXXOperatorName(OO_Array_Delete),
554      Context.VoidTy, VoidPtr);
555}
556
557/// DeclareGlobalAllocationFunction - Declares a single implicit global
558/// allocation function if it doesn't already exist.
559void Sema::DeclareGlobalAllocationFunction(DeclarationName Name,
560                                           QualType Return, QualType Argument)
561{
562  DeclContext *GlobalCtx = Context.getTranslationUnitDecl();
563
564  // Check if this function is already declared.
565  {
566    DeclContext::lookup_iterator Alloc, AllocEnd;
567    for (llvm::tie(Alloc, AllocEnd) = GlobalCtx->lookup(Name);
568         Alloc != AllocEnd; ++Alloc) {
569      // FIXME: Do we need to check for default arguments here?
570      FunctionDecl *Func = cast<FunctionDecl>(*Alloc);
571      if (Func->getNumParams() == 1 &&
572          Context.getCanonicalType(Func->getParamDecl(0)->getType())==Argument)
573        return;
574    }
575  }
576
577  QualType FnType = Context.getFunctionType(Return, &Argument, 1, false, 0);
578  FunctionDecl *Alloc =
579    FunctionDecl::Create(Context, GlobalCtx, SourceLocation(), Name,
580                         FnType, FunctionDecl::None, false, true,
581                         SourceLocation());
582  Alloc->setImplicit();
583  ParmVarDecl *Param = ParmVarDecl::Create(Context, Alloc, SourceLocation(),
584                                           0, Argument, VarDecl::None, 0);
585  Alloc->setParams(Context, &Param, 1);
586
587  // FIXME: Also add this declaration to the IdentifierResolver, but
588  // make sure it is at the end of the chain to coincide with the
589  // global scope.
590  ((DeclContext *)TUScope->getEntity())->addDecl(Alloc);
591}
592
593/// ActOnCXXDelete - Parsed a C++ 'delete' expression (C++ 5.3.5), as in:
594/// @code ::delete ptr; @endcode
595/// or
596/// @code delete [] ptr; @endcode
597Action::OwningExprResult
598Sema::ActOnCXXDelete(SourceLocation StartLoc, bool UseGlobal,
599                     bool ArrayForm, ExprArg Operand)
600{
601  // C++ 5.3.5p1: "The operand shall have a pointer type, or a class type
602  //   having a single conversion function to a pointer type. The result has
603  //   type void."
604  // DR599 amends "pointer type" to "pointer to object type" in both cases.
605
606  Expr *Ex = (Expr *)Operand.get();
607  if (!Ex->isTypeDependent()) {
608    QualType Type = Ex->getType();
609
610    if (Type->isRecordType()) {
611      // FIXME: Find that one conversion function and amend the type.
612    }
613
614    if (!Type->isPointerType())
615      return ExprError(Diag(StartLoc, diag::err_delete_operand)
616        << Type << Ex->getSourceRange());
617
618    QualType Pointee = Type->getAsPointerType()->getPointeeType();
619    if (!Pointee->isVoidType() &&
620        RequireCompleteType(StartLoc, Pointee, diag::warn_delete_incomplete,
621                               Ex->getSourceRange()))
622      return ExprError();
623    else if (!Pointee->isObjectType())
624      return ExprError(Diag(StartLoc, diag::err_delete_operand)
625        << Type << Ex->getSourceRange());
626
627    // FIXME: Look up the correct operator delete overload and pass a pointer
628    // along.
629    // FIXME: Check access and ambiguity of operator delete and destructor.
630  }
631
632  Operand.release();
633  return Owned(new (Context) CXXDeleteExpr(Context.VoidTy, UseGlobal, ArrayForm,
634                                           0, Ex, StartLoc));
635}
636
637
638/// ActOnCXXConditionDeclarationExpr - Parsed a condition declaration of a
639/// C++ if/switch/while/for statement.
640/// e.g: "if (int x = f()) {...}"
641Action::OwningExprResult
642Sema::ActOnCXXConditionDeclarationExpr(Scope *S, SourceLocation StartLoc,
643                                       Declarator &D,
644                                       SourceLocation EqualLoc,
645                                       ExprArg AssignExprVal) {
646  assert(AssignExprVal.get() && "Null assignment expression");
647
648  // C++ 6.4p2:
649  // The declarator shall not specify a function or an array.
650  // The type-specifier-seq shall not contain typedef and shall not declare a
651  // new class or enumeration.
652
653  assert(D.getDeclSpec().getStorageClassSpec() != DeclSpec::SCS_typedef &&
654         "Parser allowed 'typedef' as storage class of condition decl.");
655
656  QualType Ty = GetTypeForDeclarator(D, S);
657
658  if (Ty->isFunctionType()) { // The declarator shall not specify a function...
659    // We exit without creating a CXXConditionDeclExpr because a FunctionDecl
660    // would be created and CXXConditionDeclExpr wants a VarDecl.
661    return ExprError(Diag(StartLoc, diag::err_invalid_use_of_function_type)
662      << SourceRange(StartLoc, EqualLoc));
663  } else if (Ty->isArrayType()) { // ...or an array.
664    Diag(StartLoc, diag::err_invalid_use_of_array_type)
665      << SourceRange(StartLoc, EqualLoc);
666  } else if (const RecordType *RT = Ty->getAsRecordType()) {
667    RecordDecl *RD = RT->getDecl();
668    // The type-specifier-seq shall not declare a new class...
669    if (RD->isDefinition() && (RD->getIdentifier() == 0 || S->isDeclScope(RD)))
670      Diag(RD->getLocation(), diag::err_type_defined_in_condition);
671  } else if (const EnumType *ET = Ty->getAsEnumType()) {
672    EnumDecl *ED = ET->getDecl();
673    // ...or enumeration.
674    if (ED->isDefinition() && (ED->getIdentifier() == 0 || S->isDeclScope(ED)))
675      Diag(ED->getLocation(), diag::err_type_defined_in_condition);
676  }
677
678  DeclTy *Dcl = ActOnDeclarator(S, D, 0);
679  if (!Dcl)
680    return ExprError();
681  AddInitializerToDecl(Dcl, move(AssignExprVal));
682
683  // Mark this variable as one that is declared within a conditional.
684  if (VarDecl *VD = dyn_cast<VarDecl>((Decl *)Dcl))
685    VD->setDeclaredInCondition(true);
686
687  return Owned(new (Context) CXXConditionDeclExpr(StartLoc, EqualLoc,
688                                      cast<VarDecl>(static_cast<Decl *>(Dcl))));
689}
690
691/// CheckCXXBooleanCondition - Returns true if a conversion to bool is invalid.
692bool Sema::CheckCXXBooleanCondition(Expr *&CondExpr) {
693  // C++ 6.4p4:
694  // The value of a condition that is an initialized declaration in a statement
695  // other than a switch statement is the value of the declared variable
696  // implicitly converted to type bool. If that conversion is ill-formed, the
697  // program is ill-formed.
698  // The value of a condition that is an expression is the value of the
699  // expression, implicitly converted to bool.
700  //
701  return PerformContextuallyConvertToBool(CondExpr);
702}
703
704/// Helper function to determine whether this is the (deprecated) C++
705/// conversion from a string literal to a pointer to non-const char or
706/// non-const wchar_t (for narrow and wide string literals,
707/// respectively).
708bool
709Sema::IsStringLiteralToNonConstPointerConversion(Expr *From, QualType ToType) {
710  // Look inside the implicit cast, if it exists.
711  if (ImplicitCastExpr *Cast = dyn_cast<ImplicitCastExpr>(From))
712    From = Cast->getSubExpr();
713
714  // A string literal (2.13.4) that is not a wide string literal can
715  // be converted to an rvalue of type "pointer to char"; a wide
716  // string literal can be converted to an rvalue of type "pointer
717  // to wchar_t" (C++ 4.2p2).
718  if (StringLiteral *StrLit = dyn_cast<StringLiteral>(From))
719    if (const PointerType *ToPtrType = ToType->getAsPointerType())
720      if (const BuiltinType *ToPointeeType
721          = ToPtrType->getPointeeType()->getAsBuiltinType()) {
722        // This conversion is considered only when there is an
723        // explicit appropriate pointer target type (C++ 4.2p2).
724        if (ToPtrType->getPointeeType().getCVRQualifiers() == 0 &&
725            ((StrLit->isWide() && ToPointeeType->isWideCharType()) ||
726             (!StrLit->isWide() &&
727              (ToPointeeType->getKind() == BuiltinType::Char_U ||
728               ToPointeeType->getKind() == BuiltinType::Char_S))))
729          return true;
730      }
731
732  return false;
733}
734
735/// PerformImplicitConversion - Perform an implicit conversion of the
736/// expression From to the type ToType. Returns true if there was an
737/// error, false otherwise. The expression From is replaced with the
738/// converted expression. Flavor is the kind of conversion we're
739/// performing, used in the error message. If @p AllowExplicit,
740/// explicit user-defined conversions are permitted.
741bool
742Sema::PerformImplicitConversion(Expr *&From, QualType ToType,
743                                const char *Flavor, bool AllowExplicit)
744{
745  ImplicitConversionSequence ICS = TryImplicitConversion(From, ToType, false,
746                                                         AllowExplicit);
747  return PerformImplicitConversion(From, ToType, ICS, Flavor);
748}
749
750/// PerformImplicitConversion - Perform an implicit conversion of the
751/// expression From to the type ToType using the pre-computed implicit
752/// conversion sequence ICS. Returns true if there was an error, false
753/// otherwise. The expression From is replaced with the converted
754/// expression. Flavor is the kind of conversion we're performing,
755/// used in the error message.
756bool
757Sema::PerformImplicitConversion(Expr *&From, QualType ToType,
758                                const ImplicitConversionSequence &ICS,
759                                const char* Flavor) {
760  switch (ICS.ConversionKind) {
761  case ImplicitConversionSequence::StandardConversion:
762    if (PerformImplicitConversion(From, ToType, ICS.Standard, Flavor))
763      return true;
764    break;
765
766  case ImplicitConversionSequence::UserDefinedConversion:
767    // FIXME: This is, of course, wrong. We'll need to actually call
768    // the constructor or conversion operator, and then cope with the
769    // standard conversions.
770    ImpCastExprToType(From, ToType.getNonReferenceType(),
771                      ToType->isLValueReferenceType());
772    return false;
773
774  case ImplicitConversionSequence::EllipsisConversion:
775    assert(false && "Cannot perform an ellipsis conversion");
776    return false;
777
778  case ImplicitConversionSequence::BadConversion:
779    return true;
780  }
781
782  // Everything went well.
783  return false;
784}
785
786/// PerformImplicitConversion - Perform an implicit conversion of the
787/// expression From to the type ToType by following the standard
788/// conversion sequence SCS. Returns true if there was an error, false
789/// otherwise. The expression From is replaced with the converted
790/// expression. Flavor is the context in which we're performing this
791/// conversion, for use in error messages.
792bool
793Sema::PerformImplicitConversion(Expr *&From, QualType ToType,
794                                const StandardConversionSequence& SCS,
795                                const char *Flavor) {
796  // Overall FIXME: we are recomputing too many types here and doing
797  // far too much extra work. What this means is that we need to keep
798  // track of more information that is computed when we try the
799  // implicit conversion initially, so that we don't need to recompute
800  // anything here.
801  QualType FromType = From->getType();
802
803  if (SCS.CopyConstructor) {
804    // FIXME: Create a temporary object by calling the copy
805    // constructor.
806    ImpCastExprToType(From, ToType.getNonReferenceType(),
807                      ToType->isLValueReferenceType());
808    return false;
809  }
810
811  // Perform the first implicit conversion.
812  switch (SCS.First) {
813  case ICK_Identity:
814  case ICK_Lvalue_To_Rvalue:
815    // Nothing to do.
816    break;
817
818  case ICK_Array_To_Pointer:
819    FromType = Context.getArrayDecayedType(FromType);
820    ImpCastExprToType(From, FromType);
821    break;
822
823  case ICK_Function_To_Pointer:
824    if (Context.getCanonicalType(FromType) == Context.OverloadTy) {
825      FunctionDecl *Fn = ResolveAddressOfOverloadedFunction(From, ToType, true);
826      if (!Fn)
827        return true;
828
829      if (DiagnoseUseOfDecl(Fn, From->getSourceRange().getBegin()))
830        return true;
831
832      FixOverloadedFunctionReference(From, Fn);
833      FromType = From->getType();
834    }
835    FromType = Context.getPointerType(FromType);
836    ImpCastExprToType(From, FromType);
837    break;
838
839  default:
840    assert(false && "Improper first standard conversion");
841    break;
842  }
843
844  // Perform the second implicit conversion
845  switch (SCS.Second) {
846  case ICK_Identity:
847    // Nothing to do.
848    break;
849
850  case ICK_Integral_Promotion:
851  case ICK_Floating_Promotion:
852  case ICK_Complex_Promotion:
853  case ICK_Integral_Conversion:
854  case ICK_Floating_Conversion:
855  case ICK_Complex_Conversion:
856  case ICK_Floating_Integral:
857  case ICK_Complex_Real:
858  case ICK_Compatible_Conversion:
859      // FIXME: Go deeper to get the unqualified type!
860    FromType = ToType.getUnqualifiedType();
861    ImpCastExprToType(From, FromType);
862    break;
863
864  case ICK_Pointer_Conversion:
865    if (SCS.IncompatibleObjC) {
866      // Diagnose incompatible Objective-C conversions
867      Diag(From->getSourceRange().getBegin(),
868           diag::ext_typecheck_convert_incompatible_pointer)
869        << From->getType() << ToType << Flavor
870        << From->getSourceRange();
871    }
872
873    if (CheckPointerConversion(From, ToType))
874      return true;
875    ImpCastExprToType(From, ToType);
876    break;
877
878  case ICK_Pointer_Member:
879    if (CheckMemberPointerConversion(From, ToType))
880      return true;
881    ImpCastExprToType(From, ToType);
882    break;
883
884  case ICK_Boolean_Conversion:
885    FromType = Context.BoolTy;
886    ImpCastExprToType(From, FromType);
887    break;
888
889  default:
890    assert(false && "Improper second standard conversion");
891    break;
892  }
893
894  switch (SCS.Third) {
895  case ICK_Identity:
896    // Nothing to do.
897    break;
898
899  case ICK_Qualification:
900    // FIXME: Not sure about lvalue vs rvalue here in the presence of
901    // rvalue references.
902    ImpCastExprToType(From, ToType.getNonReferenceType(),
903                      ToType->isLValueReferenceType());
904    break;
905
906  default:
907    assert(false && "Improper second standard conversion");
908    break;
909  }
910
911  return false;
912}
913
914Sema::OwningExprResult Sema::ActOnUnaryTypeTrait(UnaryTypeTrait OTT,
915                                                 SourceLocation KWLoc,
916                                                 SourceLocation LParen,
917                                                 TypeTy *Ty,
918                                                 SourceLocation RParen) {
919  // FIXME: Some of the type traits have requirements. Interestingly, only the
920  // __is_base_of requirement is explicitly stated to be diagnosed. Indeed,
921  // G++ accepts __is_pod(Incomplete) without complaints, and claims that the
922  // type is indeed a POD.
923
924  // There is no point in eagerly computing the value. The traits are designed
925  // to be used from type trait templates, so Ty will be a template parameter
926  // 99% of the time.
927  return Owned(new (Context) UnaryTypeTraitExpr(KWLoc, OTT,
928                                      QualType::getFromOpaquePtr(Ty),
929                                      RParen, Context.BoolTy));
930}
931
932QualType Sema::CheckPointerToMemberOperands(
933  Expr *&lex, Expr *&rex, SourceLocation Loc, bool isIndirect)
934{
935  const char *OpSpelling = isIndirect ? "->*" : ".*";
936  // C++ 5.5p2
937  //   The binary operator .* [p3: ->*] binds its second operand, which shall
938  //   be of type "pointer to member of T" (where T is a completely-defined
939  //   class type) [...]
940  QualType RType = rex->getType();
941  const MemberPointerType *MemPtr = RType->getAsMemberPointerType();
942  if (!MemPtr || MemPtr->getClass()->isIncompleteType()) {
943    Diag(Loc, diag::err_bad_memptr_rhs)
944      << OpSpelling << RType << rex->getSourceRange();
945    return QualType();
946  }
947  QualType Class(MemPtr->getClass(), 0);
948
949  // C++ 5.5p2
950  //   [...] to its first operand, which shall be of class T or of a class of
951  //   which T is an unambiguous and accessible base class. [p3: a pointer to
952  //   such a class]
953  QualType LType = lex->getType();
954  if (isIndirect) {
955    if (const PointerType *Ptr = LType->getAsPointerType())
956      LType = Ptr->getPointeeType().getNonReferenceType();
957    else {
958      Diag(Loc, diag::err_bad_memptr_lhs)
959        << OpSpelling << 1 << LType << lex->getSourceRange();
960      return QualType();
961    }
962  }
963
964  if (Context.getCanonicalType(Class).getUnqualifiedType() !=
965      Context.getCanonicalType(LType).getUnqualifiedType()) {
966    BasePaths Paths(/*FindAmbiguities=*/true, /*RecordPaths=*/false,
967                    /*DetectVirtual=*/false);
968    // FIXME: Would it be useful to print full ambiguity paths,
969    // or is that overkill?
970    if (!IsDerivedFrom(LType, Class, Paths) ||
971        Paths.isAmbiguous(Context.getCanonicalType(Class))) {
972      Diag(Loc, diag::err_bad_memptr_lhs) << OpSpelling
973        << (int)isIndirect << lex->getType() << lex->getSourceRange();
974      return QualType();
975    }
976  }
977
978  // C++ 5.5p2
979  //   The result is an object or a function of the type specified by the
980  //   second operand.
981  // The cv qualifiers are the union of those in the pointer and the left side,
982  // in accordance with 5.5p5 and 5.2.5.
983  // FIXME: This returns a dereferenced member function pointer as a normal
984  // function type. However, the only operation valid on such functions is
985  // calling them. There's also a GCC extension to get a function pointer to
986  // the thing, which is another complication, because this type - unlike the
987  // type that is the result of this expression - takes the class as the first
988  // argument.
989  // We probably need a "MemberFunctionClosureType" or something like that.
990  QualType Result = MemPtr->getPointeeType();
991  if (LType.isConstQualified())
992    Result.addConst();
993  if (LType.isVolatileQualified())
994    Result.addVolatile();
995  return Result;
996}
997