SemaExprCXX.cpp revision a55834a91ff6bdf483aba26c5da64669b2464e2f 
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  if (RequireNonAbstractType(TyBeginLoc, Ty,
201                             diag::err_allocation_of_abstract_type))
202    return ExprError();
203
204  exprs.release();
205  return Owned(new (Context) CXXZeroInitValueExpr(Ty, TyBeginLoc, RParenLoc));
206}
207
208
209/// ActOnCXXNew - Parsed a C++ 'new' expression (C++ 5.3.4), as in e.g.:
210/// @code new (memory) int[size][4] @endcode
211/// or
212/// @code ::new Foo(23, "hello") @endcode
213/// For the interpretation of this heap of arguments, consult the base version.
214Action::OwningExprResult
215Sema::ActOnCXXNew(SourceLocation StartLoc, bool UseGlobal,
216                  SourceLocation PlacementLParen, MultiExprArg PlacementArgs,
217                  SourceLocation PlacementRParen, bool ParenTypeId,
218                  Declarator &D, SourceLocation ConstructorLParen,
219                  MultiExprArg ConstructorArgs,
220                  SourceLocation ConstructorRParen)
221{
222  Expr *ArraySize = 0;
223  unsigned Skip = 0;
224  // If the specified type is an array, unwrap it and save the expression.
225  if (D.getNumTypeObjects() > 0 &&
226      D.getTypeObject(0).Kind == DeclaratorChunk::Array) {
227    DeclaratorChunk &Chunk = D.getTypeObject(0);
228    if (Chunk.Arr.hasStatic)
229      return ExprError(Diag(Chunk.Loc, diag::err_static_illegal_in_new)
230        << D.getSourceRange());
231    if (!Chunk.Arr.NumElts)
232      return ExprError(Diag(Chunk.Loc, diag::err_array_new_needs_size)
233        << D.getSourceRange());
234    ArraySize = static_cast<Expr*>(Chunk.Arr.NumElts);
235    Skip = 1;
236  }
237
238  QualType AllocType = GetTypeForDeclarator(D, /*Scope=*/0, Skip);
239  if (D.getInvalidType())
240    return ExprError();
241
242  if (CheckAllocatedType(AllocType, D))
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  if (AllocType->isFunctionType())
364    return Diag(D.getSourceRange().getBegin(), diag::err_bad_new_type)
365      << AllocType << 0 << D.getSourceRange();
366  else if (AllocType->isReferenceType())
367    return Diag(D.getSourceRange().getBegin(), diag::err_bad_new_type)
368      << AllocType << 1 << D.getSourceRange();
369  else if (!AllocType->isDependentType() &&
370           RequireCompleteType(D.getSourceRange().getBegin(), AllocType,
371                               diag::err_new_incomplete_type,
372                               D.getSourceRange()))
373    return true;
374  else if (RequireNonAbstractType(D.getSourceRange().getBegin(), AllocType,
375                                  diag::err_allocation_of_abstract_type))
376    return true;
377
378  // Every dimension shall be of constant size.
379  unsigned i = 1;
380  while (const ArrayType *Array = Context.getAsArrayType(AllocType)) {
381    if (!Array->isConstantArrayType()) {
382      Diag(D.getTypeObject(i).Loc, diag::err_new_array_nonconst)
383        << static_cast<Expr*>(D.getTypeObject(i).Arr.NumElts)->getSourceRange();
384      return true;
385    }
386    AllocType = Array->getElementType();
387    ++i;
388  }
389
390  return false;
391}
392
393/// FindAllocationFunctions - Finds the overloads of operator new and delete
394/// that are appropriate for the allocation.
395bool Sema::FindAllocationFunctions(SourceLocation StartLoc, SourceRange Range,
396                                   bool UseGlobal, QualType AllocType,
397                                   bool IsArray, Expr **PlaceArgs,
398                                   unsigned NumPlaceArgs,
399                                   FunctionDecl *&OperatorNew,
400                                   FunctionDecl *&OperatorDelete)
401{
402  // --- Choosing an allocation function ---
403  // C++ 5.3.4p8 - 14 & 18
404  // 1) If UseGlobal is true, only look in the global scope. Else, also look
405  //   in the scope of the allocated class.
406  // 2) If an array size is given, look for operator new[], else look for
407  //   operator new.
408  // 3) The first argument is always size_t. Append the arguments from the
409  //   placement form.
410  // FIXME: Also find the appropriate delete operator.
411
412  llvm::SmallVector<Expr*, 8> AllocArgs(1 + NumPlaceArgs);
413  // We don't care about the actual value of this argument.
414  // FIXME: Should the Sema create the expression and embed it in the syntax
415  // tree? Or should the consumer just recalculate the value?
416  AllocArgs[0] = new (Context) IntegerLiteral(llvm::APInt::getNullValue(
417                                        Context.Target.getPointerWidth(0)),
418                                    Context.getSizeType(),
419                                    SourceLocation());
420  std::copy(PlaceArgs, PlaceArgs + NumPlaceArgs, AllocArgs.begin() + 1);
421
422  DeclarationName NewName = Context.DeclarationNames.getCXXOperatorName(
423                                        IsArray ? OO_Array_New : OO_New);
424  if (AllocType->isRecordType() && !UseGlobal) {
425    CXXRecordDecl *Record
426      = cast<CXXRecordDecl>(AllocType->getAsRecordType()->getDecl());
427    // FIXME: We fail to find inherited overloads.
428    if (FindAllocationOverload(StartLoc, Range, NewName, &AllocArgs[0],
429                          AllocArgs.size(), Record, /*AllowMissing=*/true,
430                          OperatorNew))
431      return true;
432  }
433  if (!OperatorNew) {
434    // Didn't find a member overload. Look for a global one.
435    DeclareGlobalNewDelete();
436    DeclContext *TUDecl = Context.getTranslationUnitDecl();
437    if (FindAllocationOverload(StartLoc, Range, NewName, &AllocArgs[0],
438                          AllocArgs.size(), TUDecl, /*AllowMissing=*/false,
439                          OperatorNew))
440      return true;
441  }
442
443  // FIXME: This is leaked on error. But so much is currently in Sema that it's
444  // easier to clean it in one go.
445  AllocArgs[0]->Destroy(Context);
446  return false;
447}
448
449/// FindAllocationOverload - Find an fitting overload for the allocation
450/// function in the specified scope.
451bool Sema::FindAllocationOverload(SourceLocation StartLoc, SourceRange Range,
452                                  DeclarationName Name, Expr** Args,
453                                  unsigned NumArgs, DeclContext *Ctx,
454                                  bool AllowMissing, FunctionDecl *&Operator)
455{
456  DeclContext::lookup_iterator Alloc, AllocEnd;
457  llvm::tie(Alloc, AllocEnd) = Ctx->lookup(Context, Name);
458  if (Alloc == AllocEnd) {
459    if (AllowMissing)
460      return false;
461    return Diag(StartLoc, diag::err_ovl_no_viable_function_in_call)
462      << Name << Range;
463  }
464
465  OverloadCandidateSet Candidates;
466  for (; Alloc != AllocEnd; ++Alloc) {
467    // Even member operator new/delete are implicitly treated as
468    // static, so don't use AddMemberCandidate.
469    if (FunctionDecl *Fn = dyn_cast<FunctionDecl>(*Alloc))
470      AddOverloadCandidate(Fn, Args, NumArgs, Candidates,
471                           /*SuppressUserConversions=*/false);
472  }
473
474  // Do the resolution.
475  OverloadCandidateSet::iterator Best;
476  switch(BestViableFunction(Candidates, Best)) {
477  case OR_Success: {
478    // Got one!
479    FunctionDecl *FnDecl = Best->Function;
480    // The first argument is size_t, and the first parameter must be size_t,
481    // too. This is checked on declaration and can be assumed. (It can't be
482    // asserted on, though, since invalid decls are left in there.)
483    for (unsigned i = 1; i < NumArgs; ++i) {
484      // FIXME: Passing word to diagnostic.
485      if (PerformCopyInitialization(Args[i-1],
486                                    FnDecl->getParamDecl(i)->getType(),
487                                    "passing"))
488        return true;
489    }
490    Operator = FnDecl;
491    return false;
492  }
493
494  case OR_No_Viable_Function:
495    if (AllowMissing)
496      return false;
497    Diag(StartLoc, diag::err_ovl_no_viable_function_in_call)
498      << Name << Range;
499    PrintOverloadCandidates(Candidates, /*OnlyViable=*/false);
500    return true;
501
502  case OR_Ambiguous:
503    Diag(StartLoc, diag::err_ovl_ambiguous_call)
504      << Name << Range;
505    PrintOverloadCandidates(Candidates, /*OnlyViable=*/true);
506    return true;
507
508  case OR_Deleted:
509    Diag(StartLoc, diag::err_ovl_deleted_call)
510      << Best->Function->isDeleted()
511      << Name << Range;
512    PrintOverloadCandidates(Candidates, /*OnlyViable=*/true);
513    return true;
514  }
515  assert(false && "Unreachable, bad result from BestViableFunction");
516  return true;
517}
518
519
520/// DeclareGlobalNewDelete - Declare the global forms of operator new and
521/// delete. These are:
522/// @code
523///   void* operator new(std::size_t) throw(std::bad_alloc);
524///   void* operator new[](std::size_t) throw(std::bad_alloc);
525///   void operator delete(void *) throw();
526///   void operator delete[](void *) throw();
527/// @endcode
528/// Note that the placement and nothrow forms of new are *not* implicitly
529/// declared. Their use requires including \<new\>.
530void Sema::DeclareGlobalNewDelete()
531{
532  if (GlobalNewDeleteDeclared)
533    return;
534  GlobalNewDeleteDeclared = true;
535
536  QualType VoidPtr = Context.getPointerType(Context.VoidTy);
537  QualType SizeT = Context.getSizeType();
538
539  // FIXME: Exception specifications are not added.
540  DeclareGlobalAllocationFunction(
541      Context.DeclarationNames.getCXXOperatorName(OO_New),
542      VoidPtr, SizeT);
543  DeclareGlobalAllocationFunction(
544      Context.DeclarationNames.getCXXOperatorName(OO_Array_New),
545      VoidPtr, SizeT);
546  DeclareGlobalAllocationFunction(
547      Context.DeclarationNames.getCXXOperatorName(OO_Delete),
548      Context.VoidTy, VoidPtr);
549  DeclareGlobalAllocationFunction(
550      Context.DeclarationNames.getCXXOperatorName(OO_Array_Delete),
551      Context.VoidTy, VoidPtr);
552}
553
554/// DeclareGlobalAllocationFunction - Declares a single implicit global
555/// allocation function if it doesn't already exist.
556void Sema::DeclareGlobalAllocationFunction(DeclarationName Name,
557                                           QualType Return, QualType Argument)
558{
559  DeclContext *GlobalCtx = Context.getTranslationUnitDecl();
560
561  // Check if this function is already declared.
562  {
563    DeclContext::lookup_iterator Alloc, AllocEnd;
564    for (llvm::tie(Alloc, AllocEnd) = GlobalCtx->lookup(Context, Name);
565         Alloc != AllocEnd; ++Alloc) {
566      // FIXME: Do we need to check for default arguments here?
567      FunctionDecl *Func = cast<FunctionDecl>(*Alloc);
568      if (Func->getNumParams() == 1 &&
569          Context.getCanonicalType(Func->getParamDecl(0)->getType())==Argument)
570        return;
571    }
572  }
573
574  QualType FnType = Context.getFunctionType(Return, &Argument, 1, false, 0);
575  FunctionDecl *Alloc =
576    FunctionDecl::Create(Context, GlobalCtx, SourceLocation(), Name,
577                         FnType, FunctionDecl::None, false, true,
578                         SourceLocation());
579  Alloc->setImplicit();
580  ParmVarDecl *Param = ParmVarDecl::Create(Context, Alloc, SourceLocation(),
581                                           0, Argument, VarDecl::None, 0);
582  Alloc->setParams(Context, &Param, 1);
583
584  // FIXME: Also add this declaration to the IdentifierResolver, but
585  // make sure it is at the end of the chain to coincide with the
586  // global scope.
587  ((DeclContext *)TUScope->getEntity())->addDecl(Context, Alloc);
588}
589
590/// ActOnCXXDelete - Parsed a C++ 'delete' expression (C++ 5.3.5), as in:
591/// @code ::delete ptr; @endcode
592/// or
593/// @code delete [] ptr; @endcode
594Action::OwningExprResult
595Sema::ActOnCXXDelete(SourceLocation StartLoc, bool UseGlobal,
596                     bool ArrayForm, ExprArg Operand)
597{
598  // C++ 5.3.5p1: "The operand shall have a pointer type, or a class type
599  //   having a single conversion function to a pointer type. The result has
600  //   type void."
601  // DR599 amends "pointer type" to "pointer to object type" in both cases.
602
603  Expr *Ex = (Expr *)Operand.get();
604  if (!Ex->isTypeDependent()) {
605    QualType Type = Ex->getType();
606
607    if (Type->isRecordType()) {
608      // FIXME: Find that one conversion function and amend the type.
609    }
610
611    if (!Type->isPointerType())
612      return ExprError(Diag(StartLoc, diag::err_delete_operand)
613        << Type << Ex->getSourceRange());
614
615    QualType Pointee = Type->getAsPointerType()->getPointeeType();
616    if (Pointee->isFunctionType() || Pointee->isVoidType())
617      return ExprError(Diag(StartLoc, diag::err_delete_operand)
618        << Type << Ex->getSourceRange());
619    else if (!Pointee->isDependentType() &&
620             RequireCompleteType(StartLoc, Pointee,
621                                 diag::warn_delete_incomplete,
622                                 Ex->getSourceRange()))
623      return ExprError();
624
625    // FIXME: Look up the correct operator delete overload and pass a pointer
626    // along.
627    // FIXME: Check access and ambiguity of operator delete and destructor.
628  }
629
630  Operand.release();
631  return Owned(new (Context) CXXDeleteExpr(Context.VoidTy, UseGlobal, ArrayForm,
632                                           0, Ex, StartLoc));
633}
634
635
636/// ActOnCXXConditionDeclarationExpr - Parsed a condition declaration of a
637/// C++ if/switch/while/for statement.
638/// e.g: "if (int x = f()) {...}"
639Action::OwningExprResult
640Sema::ActOnCXXConditionDeclarationExpr(Scope *S, SourceLocation StartLoc,
641                                       Declarator &D,
642                                       SourceLocation EqualLoc,
643                                       ExprArg AssignExprVal) {
644  assert(AssignExprVal.get() && "Null assignment expression");
645
646  // C++ 6.4p2:
647  // The declarator shall not specify a function or an array.
648  // The type-specifier-seq shall not contain typedef and shall not declare a
649  // new class or enumeration.
650
651  assert(D.getDeclSpec().getStorageClassSpec() != DeclSpec::SCS_typedef &&
652         "Parser allowed 'typedef' as storage class of condition decl.");
653
654  QualType Ty = GetTypeForDeclarator(D, S);
655
656  if (Ty->isFunctionType()) { // The declarator shall not specify a function...
657    // We exit without creating a CXXConditionDeclExpr because a FunctionDecl
658    // would be created and CXXConditionDeclExpr wants a VarDecl.
659    return ExprError(Diag(StartLoc, diag::err_invalid_use_of_function_type)
660      << SourceRange(StartLoc, EqualLoc));
661  } else if (Ty->isArrayType()) { // ...or an array.
662    Diag(StartLoc, diag::err_invalid_use_of_array_type)
663      << SourceRange(StartLoc, EqualLoc);
664  } else if (const RecordType *RT = Ty->getAsRecordType()) {
665    RecordDecl *RD = RT->getDecl();
666    // The type-specifier-seq shall not declare a new class...
667    if (RD->isDefinition() &&
668        (RD->getIdentifier() == 0 || S->isDeclScope(DeclPtrTy::make(RD))))
669      Diag(RD->getLocation(), diag::err_type_defined_in_condition);
670  } else if (const EnumType *ET = Ty->getAsEnumType()) {
671    EnumDecl *ED = ET->getDecl();
672    // ...or enumeration.
673    if (ED->isDefinition() &&
674        (ED->getIdentifier() == 0 || S->isDeclScope(DeclPtrTy::make(ED))))
675      Diag(ED->getLocation(), diag::err_type_defined_in_condition);
676  }
677
678  DeclPtrTy Dcl = ActOnDeclarator(S, D, DeclPtrTy());
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  // We know that the decl had to be a VarDecl because that is the only type of
685  // decl that can be assigned and the grammar requires an '='.
686  VarDecl *VD = cast<VarDecl>(Dcl.getAs<Decl>());
687  VD->setDeclaredInCondition(true);
688  return Owned(new (Context) CXXConditionDeclExpr(StartLoc, EqualLoc, VD));
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. @p Elidable should be true
741/// when called for copies which may be elided (C++ 12.8p15). C++0x overload
742/// resolution works differently in that case.
743bool
744Sema::PerformImplicitConversion(Expr *&From, QualType ToType,
745                                const char *Flavor, bool AllowExplicit,
746                                bool Elidable)
747{
748  ImplicitConversionSequence ICS;
749  ICS.ConversionKind = ImplicitConversionSequence::BadConversion;
750  if (Elidable && getLangOptions().CPlusPlus0x) {
751    ICS = TryImplicitConversion(From, ToType, /*SuppressUserConversions*/false,
752                                AllowExplicit, /*ForceRValue*/true);
753  }
754  if (ICS.ConversionKind == ImplicitConversionSequence::BadConversion) {
755    ICS = TryImplicitConversion(From, ToType, false, AllowExplicit);
756  }
757  return PerformImplicitConversion(From, ToType, ICS, Flavor);
758}
759
760/// PerformImplicitConversion - Perform an implicit conversion of the
761/// expression From to the type ToType using the pre-computed implicit
762/// conversion sequence ICS. Returns true if there was an error, false
763/// otherwise. The expression From is replaced with the converted
764/// expression. Flavor is the kind of conversion we're performing,
765/// used in the error message.
766bool
767Sema::PerformImplicitConversion(Expr *&From, QualType ToType,
768                                const ImplicitConversionSequence &ICS,
769                                const char* Flavor) {
770  switch (ICS.ConversionKind) {
771  case ImplicitConversionSequence::StandardConversion:
772    if (PerformImplicitConversion(From, ToType, ICS.Standard, Flavor))
773      return true;
774    break;
775
776  case ImplicitConversionSequence::UserDefinedConversion:
777    // FIXME: This is, of course, wrong. We'll need to actually call
778    // the constructor or conversion operator, and then cope with the
779    // standard conversions.
780    ImpCastExprToType(From, ToType.getNonReferenceType(),
781                      ToType->isLValueReferenceType());
782    return false;
783
784  case ImplicitConversionSequence::EllipsisConversion:
785    assert(false && "Cannot perform an ellipsis conversion");
786    return false;
787
788  case ImplicitConversionSequence::BadConversion:
789    return true;
790  }
791
792  // Everything went well.
793  return false;
794}
795
796/// PerformImplicitConversion - Perform an implicit conversion of the
797/// expression From to the type ToType by following the standard
798/// conversion sequence SCS. Returns true if there was an error, false
799/// otherwise. The expression From is replaced with the converted
800/// expression. Flavor is the context in which we're performing this
801/// conversion, for use in error messages.
802bool
803Sema::PerformImplicitConversion(Expr *&From, QualType ToType,
804                                const StandardConversionSequence& SCS,
805                                const char *Flavor) {
806  // Overall FIXME: we are recomputing too many types here and doing
807  // far too much extra work. What this means is that we need to keep
808  // track of more information that is computed when we try the
809  // implicit conversion initially, so that we don't need to recompute
810  // anything here.
811  QualType FromType = From->getType();
812
813  if (SCS.CopyConstructor) {
814    // FIXME: Create a temporary object by calling the copy
815    // constructor.
816    ImpCastExprToType(From, ToType.getNonReferenceType(),
817                      ToType->isLValueReferenceType());
818    return false;
819  }
820
821  // Perform the first implicit conversion.
822  switch (SCS.First) {
823  case ICK_Identity:
824  case ICK_Lvalue_To_Rvalue:
825    // Nothing to do.
826    break;
827
828  case ICK_Array_To_Pointer:
829    FromType = Context.getArrayDecayedType(FromType);
830    ImpCastExprToType(From, FromType);
831    break;
832
833  case ICK_Function_To_Pointer:
834    if (Context.getCanonicalType(FromType) == Context.OverloadTy) {
835      FunctionDecl *Fn = ResolveAddressOfOverloadedFunction(From, ToType, true);
836      if (!Fn)
837        return true;
838
839      if (DiagnoseUseOfDecl(Fn, From->getSourceRange().getBegin()))
840        return true;
841
842      FixOverloadedFunctionReference(From, Fn);
843      FromType = From->getType();
844    }
845    FromType = Context.getPointerType(FromType);
846    ImpCastExprToType(From, FromType);
847    break;
848
849  default:
850    assert(false && "Improper first standard conversion");
851    break;
852  }
853
854  // Perform the second implicit conversion
855  switch (SCS.Second) {
856  case ICK_Identity:
857    // Nothing to do.
858    break;
859
860  case ICK_Integral_Promotion:
861  case ICK_Floating_Promotion:
862  case ICK_Complex_Promotion:
863  case ICK_Integral_Conversion:
864  case ICK_Floating_Conversion:
865  case ICK_Complex_Conversion:
866  case ICK_Floating_Integral:
867  case ICK_Complex_Real:
868  case ICK_Compatible_Conversion:
869      // FIXME: Go deeper to get the unqualified type!
870    FromType = ToType.getUnqualifiedType();
871    ImpCastExprToType(From, FromType);
872    break;
873
874  case ICK_Pointer_Conversion:
875    if (SCS.IncompatibleObjC) {
876      // Diagnose incompatible Objective-C conversions
877      Diag(From->getSourceRange().getBegin(),
878           diag::ext_typecheck_convert_incompatible_pointer)
879        << From->getType() << ToType << Flavor
880        << From->getSourceRange();
881    }
882
883    if (CheckPointerConversion(From, ToType))
884      return true;
885    ImpCastExprToType(From, ToType);
886    break;
887
888  case ICK_Pointer_Member:
889    if (CheckMemberPointerConversion(From, ToType))
890      return true;
891    ImpCastExprToType(From, ToType);
892    break;
893
894  case ICK_Boolean_Conversion:
895    FromType = Context.BoolTy;
896    ImpCastExprToType(From, FromType);
897    break;
898
899  default:
900    assert(false && "Improper second standard conversion");
901    break;
902  }
903
904  switch (SCS.Third) {
905  case ICK_Identity:
906    // Nothing to do.
907    break;
908
909  case ICK_Qualification:
910    // FIXME: Not sure about lvalue vs rvalue here in the presence of
911    // rvalue references.
912    ImpCastExprToType(From, ToType.getNonReferenceType(),
913                      ToType->isLValueReferenceType());
914    break;
915
916  default:
917    assert(false && "Improper second standard conversion");
918    break;
919  }
920
921  return false;
922}
923
924Sema::OwningExprResult Sema::ActOnUnaryTypeTrait(UnaryTypeTrait OTT,
925                                                 SourceLocation KWLoc,
926                                                 SourceLocation LParen,
927                                                 TypeTy *Ty,
928                                                 SourceLocation RParen) {
929  // FIXME: Some of the type traits have requirements. Interestingly, only the
930  // __is_base_of requirement is explicitly stated to be diagnosed. Indeed,
931  // G++ accepts __is_pod(Incomplete) without complaints, and claims that the
932  // type is indeed a POD.
933
934  // There is no point in eagerly computing the value. The traits are designed
935  // to be used from type trait templates, so Ty will be a template parameter
936  // 99% of the time.
937  return Owned(new (Context) UnaryTypeTraitExpr(KWLoc, OTT,
938                                      QualType::getFromOpaquePtr(Ty),
939                                      RParen, Context.BoolTy));
940}
941
942QualType Sema::CheckPointerToMemberOperands(
943  Expr *&lex, Expr *&rex, SourceLocation Loc, bool isIndirect)
944{
945  const char *OpSpelling = isIndirect ? "->*" : ".*";
946  // C++ 5.5p2
947  //   The binary operator .* [p3: ->*] binds its second operand, which shall
948  //   be of type "pointer to member of T" (where T is a completely-defined
949  //   class type) [...]
950  QualType RType = rex->getType();
951  const MemberPointerType *MemPtr = RType->getAsMemberPointerType();
952  if (!MemPtr) {
953    Diag(Loc, diag::err_bad_memptr_rhs)
954      << OpSpelling << RType << rex->getSourceRange();
955    return QualType();
956  } else if (RequireCompleteType(Loc, QualType(MemPtr->getClass(), 0),
957                                 diag::err_memptr_rhs_incomplete,
958                                 rex->getSourceRange()))
959    return QualType();
960
961  QualType Class(MemPtr->getClass(), 0);
962
963  // C++ 5.5p2
964  //   [...] to its first operand, which shall be of class T or of a class of
965  //   which T is an unambiguous and accessible base class. [p3: a pointer to
966  //   such a class]
967  QualType LType = lex->getType();
968  if (isIndirect) {
969    if (const PointerType *Ptr = LType->getAsPointerType())
970      LType = Ptr->getPointeeType().getNonReferenceType();
971    else {
972      Diag(Loc, diag::err_bad_memptr_lhs)
973        << OpSpelling << 1 << LType << lex->getSourceRange();
974      return QualType();
975    }
976  }
977
978  if (Context.getCanonicalType(Class).getUnqualifiedType() !=
979      Context.getCanonicalType(LType).getUnqualifiedType()) {
980    BasePaths Paths(/*FindAmbiguities=*/true, /*RecordPaths=*/false,
981                    /*DetectVirtual=*/false);
982    // FIXME: Would it be useful to print full ambiguity paths,
983    // or is that overkill?
984    if (!IsDerivedFrom(LType, Class, Paths) ||
985        Paths.isAmbiguous(Context.getCanonicalType(Class))) {
986      Diag(Loc, diag::err_bad_memptr_lhs) << OpSpelling
987        << (int)isIndirect << lex->getType() << lex->getSourceRange();
988      return QualType();
989    }
990  }
991
992  // C++ 5.5p2
993  //   The result is an object or a function of the type specified by the
994  //   second operand.
995  // The cv qualifiers are the union of those in the pointer and the left side,
996  // in accordance with 5.5p5 and 5.2.5.
997  // FIXME: This returns a dereferenced member function pointer as a normal
998  // function type. However, the only operation valid on such functions is
999  // calling them. There's also a GCC extension to get a function pointer to
1000  // the thing, which is another complication, because this type - unlike the
1001  // type that is the result of this expression - takes the class as the first
1002  // argument.
1003  // We probably need a "MemberFunctionClosureType" or something like that.
1004  QualType Result = MemPtr->getPointeeType();
1005  if (LType.isConstQualified())
1006    Result.addConst();
1007  if (LType.isVolatileQualified())
1008    Result.addVolatile();
1009  return Result;
1010}
1011