path: root/include/clang/Sema/Overload.h

//===--- Overload.h - C++ Overloading ---------------------------*- C++ -*-===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file defines the data structures and types used in C++
// overload resolution.
//
//===----------------------------------------------------------------------===//

#ifndef LLVM_CLANG_SEMA_OVERLOAD_H
#define LLVM_CLANG_SEMA_OVERLOAD_H

#include "clang/AST/Decl.h"
#include "clang/AST/DeclTemplate.h"
#include "clang/AST/Expr.h"
#include "clang/AST/TemplateBase.h"
#include "clang/AST/Type.h"
#include "clang/AST/UnresolvedSet.h"
#include "clang/Sema/SemaFixItUtils.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/Support/Allocator.h"

namespace clang {
  class ASTContext;
  class CXXConstructorDecl;
  class CXXConversionDecl;
  class FunctionDecl;
  class Sema;

  /// OverloadingResult - Capture the result of performing overload
  /// resolution.
  enum OverloadingResult {
    OR_Success,             ///< Overload resolution succeeded.
    OR_No_Viable_Function,  ///< No viable function found.
    OR_Ambiguous,           ///< Ambiguous candidates found.
    OR_Deleted              ///< Succeeded, but refers to a deleted function.
  };
  
  enum OverloadCandidateDisplayKind {
    /// Requests that all candidates be shown.  Viable candidates will
    /// be printed first.
    OCD_AllCandidates,

    /// Requests that only viable candidates be shown.
    OCD_ViableCandidates
  };

  /// ImplicitConversionKind - The kind of implicit conversion used to
  /// convert an argument to a parameter's type. The enumerator values
  /// match with Table 9 of (C++ 13.3.3.1.1) and are listed such that
  /// better conversion kinds have smaller values.
  enum ImplicitConversionKind {
    ICK_Identity = 0,          ///< Identity conversion (no conversion)
    ICK_Lvalue_To_Rvalue,      ///< Lvalue-to-rvalue conversion (C++ 4.1)
    ICK_Array_To_Pointer,      ///< Array-to-pointer conversion (C++ 4.2)
    ICK_Function_To_Pointer,   ///< Function-to-pointer (C++ 4.3)
    ICK_NoReturn_Adjustment,   ///< Removal of noreturn from a type (Clang)
    ICK_Qualification,         ///< Qualification conversions (C++ 4.4)
    ICK_Integral_Promotion,    ///< Integral promotions (C++ 4.5)
    ICK_Floating_Promotion,    ///< Floating point promotions (C++ 4.6)
    ICK_Complex_Promotion,     ///< Complex promotions (Clang extension)
    ICK_Integral_Conversion,   ///< Integral conversions (C++ 4.7)
    ICK_Floating_Conversion,   ///< Floating point conversions (C++ 4.8)
    ICK_Complex_Conversion,    ///< Complex conversions (C99 6.3.1.6)
    ICK_Floating_Integral,     ///< Floating-integral conversions (C++ 4.9)
    ICK_Pointer_Conversion,    ///< Pointer conversions (C++ 4.10)
    ICK_Pointer_Member,        ///< Pointer-to-member conversions (C++ 4.11)
    ICK_Boolean_Conversion,    ///< Boolean conversions (C++ 4.12)
    ICK_Compatible_Conversion, ///< Conversions between compatible types in C99
    ICK_Derived_To_Base,       ///< Derived-to-base (C++ [over.best.ics])
    ICK_Vector_Conversion,     ///< Vector conversions
    ICK_Vector_Splat,          ///< A vector splat from an arithmetic type
    ICK_Complex_Real,          ///< Complex-real conversions (C99 6.3.1.7)
    ICK_Block_Pointer_Conversion,    ///< Block Pointer conversions 
    ICK_TransparentUnionConversion, ///< Transparent Union Conversions
    ICK_Writeback_Conversion,  ///< Objective-C ARC writeback conversion
    ICK_Zero_Event_Conversion, ///< Zero constant to event (OpenCL1.2 6.12.10)
    ICK_Num_Conversion_Kinds   ///< The number of conversion kinds
  };

  /// ImplicitConversionCategory - The category of an implicit
  /// conversion kind. The enumerator values match with Table 9 of
  /// (C++ 13.3.3.1.1) and are listed such that better conversion
  /// categories have smaller values.
  enum ImplicitConversionCategory {
    ICC_Identity = 0,              ///< Identity
    ICC_Lvalue_Transformation,     ///< Lvalue transformation
    ICC_Qualification_Adjustment,  ///< Qualification adjustment
    ICC_Promotion,                 ///< Promotion
    ICC_Conversion                 ///< Conversion
  };

  ImplicitConversionCategory
  GetConversionCategory(ImplicitConversionKind Kind);

  /// ImplicitConversionRank - The rank of an implicit conversion
  /// kind. The enumerator values match with Table 9 of (C++
  /// 13.3.3.1.1) and are listed such that better conversion ranks
  /// have smaller values.
  enum ImplicitConversionRank {
    ICR_Exact_Match = 0,         ///< Exact Match
    ICR_Promotion,               ///< Promotion
    ICR_Conversion,              ///< Conversion
    ICR_Complex_Real_Conversion, ///< Complex <-> Real conversion
    ICR_Writeback_Conversion     ///< ObjC ARC writeback conversion
  };

  ImplicitConversionRank GetConversionRank(ImplicitConversionKind Kind);

  /// NarrowingKind - The kind of narrowing conversion being performed by a
  /// standard conversion sequence according to C++11 [dcl.init.list]p7.
  enum NarrowingKind {
    /// Not a narrowing conversion.
    NK_Not_Narrowing,

    /// A narrowing conversion by virtue of the source and destination types.
    NK_Type_Narrowing,

    /// A narrowing conversion, because a constant expression got narrowed.
    NK_Constant_Narrowing,

    /// A narrowing conversion, because a non-constant-expression variable might
    /// have got narrowed.
    NK_Variable_Narrowing
  };

  /// StandardConversionSequence - represents a standard conversion
  /// sequence (C++ 13.3.3.1.1). A standard conversion sequence
  /// contains between zero and three conversions. If a particular
  /// conversion is not needed, it will be set to the identity conversion
  /// (ICK_Identity). Note that the three conversions are
  /// specified as separate members (rather than in an array) so that
  /// we can keep the size of a standard conversion sequence to a
  /// single word.
  class StandardConversionSequence {
  public:
    /// First -- The first conversion can be an lvalue-to-rvalue
    /// conversion, array-to-pointer conversion, or
    /// function-to-pointer conversion.
    ImplicitConversionKind First : 8;

    /// Second - The second conversion can be an integral promotion,
    /// floating point promotion, integral conversion, floating point
    /// conversion, floating-integral conversion, pointer conversion,
    /// pointer-to-member conversion, or boolean conversion.
    ImplicitConversionKind Second : 8;

    /// Third - The third conversion can be a qualification conversion.
    ImplicitConversionKind Third : 8;

    /// \brief Whether this is the deprecated conversion of a
    /// string literal to a pointer to non-const character data
    /// (C++ 4.2p2).
    unsigned DeprecatedStringLiteralToCharPtr : 1;

    /// \brief Whether the qualification conversion involves a change in the
    /// Objective-C lifetime (for automatic reference counting).
    unsigned QualificationIncludesObjCLifetime : 1;
    
    /// IncompatibleObjC - Whether this is an Objective-C conversion
    /// that we should warn about (if we actually use it).
    unsigned IncompatibleObjC : 1;

    /// ReferenceBinding - True when this is a reference binding
    /// (C++ [over.ics.ref]).
    unsigned ReferenceBinding : 1;

    /// DirectBinding - True when this is a reference binding that is a
    /// direct binding (C++ [dcl.init.ref]).
    unsigned DirectBinding : 1;

    /// \brief Whether this is an lvalue reference binding (otherwise, it's
    /// an rvalue reference binding).
    unsigned IsLvalueReference : 1;
    
    /// \brief Whether we're binding to a function lvalue.
    unsigned BindsToFunctionLvalue : 1;
    
    /// \brief Whether we're binding to an rvalue.
    unsigned BindsToRvalue : 1;
    
    /// \brief Whether this binds an implicit object argument to a 
    /// non-static member function without a ref-qualifier.
    unsigned BindsImplicitObjectArgumentWithoutRefQualifier : 1;
    
    /// \brief Whether this binds a reference to an object with a different
    /// Objective-C lifetime qualifier.
    unsigned ObjCLifetimeConversionBinding : 1;
    
    /// FromType - The type that this conversion is converting
    /// from. This is an opaque pointer that can be translated into a
    /// QualType.
    void *FromTypePtr;

    /// ToType - The types that this conversion is converting to in
    /// each step. This is an opaque pointer that can be translated
    /// into a QualType.
    void *ToTypePtrs[3];

    /// CopyConstructor - The copy constructor that is used to perform
    /// this conversion, when the conversion is actually just the
    /// initialization of an object via copy constructor. Such
    /// conversions are either identity conversions or derived-to-base
    /// conversions.
    CXXConstructorDecl *CopyConstructor;

    void setFromType(QualType T) { FromTypePtr = T.getAsOpaquePtr(); }
    void setToType(unsigned Idx, QualType T) { 
      assert(Idx < 3 && "To type index is out of range");
      ToTypePtrs[Idx] = T.getAsOpaquePtr(); 
    }
    void setAllToTypes(QualType T) {
      ToTypePtrs[0] = T.getAsOpaquePtr(); 
      ToTypePtrs[1] = ToTypePtrs[0];
      ToTypePtrs[2] = ToTypePtrs[0];
    }

    QualType getFromType() const {
      return QualType::getFromOpaquePtr(FromTypePtr);
    }
    QualType getToType(unsigned Idx) const {
      assert(Idx <