| //===-- Redeclarable.h - Base for Decls that can be redeclared -*- 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 Redeclarable interface. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #ifndef LLVM_CLANG_AST_REDECLARABLE_H |
| #define LLVM_CLANG_AST_REDECLARABLE_H |
| |
| #include "llvm/ADT/PointerIntPair.h" |
| #include "llvm/Support/Casting.h" |
| #include <iterator> |
| |
| namespace clang { |
| |
| /// \brief Provides common interface for the Decls that can be redeclared. |
| template<typename decl_type> |
| class Redeclarable { |
| |
| protected: |
| // FIXME: PointerIntPair is a value class that should not be inherited from. |
| // This should change to using containment. |
| struct DeclLink : public llvm::PointerIntPair<decl_type *, 1, bool> { |
| DeclLink(decl_type *D, bool isLatest) |
| : llvm::PointerIntPair<decl_type *, 1, bool>(D, isLatest) { } |
| |
| typedef llvm::PointerIntPair<decl_type *, 1, bool> base_type; |
| |
| bool NextIsPrevious() const { return base_type::getInt() == false; } |
| bool NextIsLatest() const { return base_type::getInt() == true; } |
| decl_type *getNext() const { return base_type::getPointer(); } |
| }; |
| |
| struct PreviousDeclLink : public DeclLink { |
| PreviousDeclLink(decl_type *D) : DeclLink(D, false) { } |
| }; |
| |
| struct LatestDeclLink : public DeclLink { |
| LatestDeclLink(decl_type *D) : DeclLink(D, true) { } |
| }; |
| |
| /// \brief Points to the next redeclaration in the chain. |
| /// |
| /// If NextIsPrevious() is true, this is a link to the previous declaration |
| /// of this same Decl. If NextIsLatest() is true, this is the first |
| /// declaration and Link points to the latest declaration. For example: |
| /// |
| /// #1 int f(int x, int y = 1); // <pointer to #3, true> |
| /// #2 int f(int x = 0, int y); // <pointer to #1, false> |
| /// #3 int f(int x, int y) { return x + y; } // <pointer to #2, false> |
| /// |
| /// If there is only one declaration, it is <pointer to self, true> |
| DeclLink RedeclLink; |
| |
| public: |
| Redeclarable() : RedeclLink(LatestDeclLink(static_cast<decl_type*>(this))) { } |
| |
| /// \brief Return the previous declaration of this declaration or NULL if this |
| /// is the first declaration. |
| decl_type *getPreviousDeclaration() { |
| if (RedeclLink.NextIsPrevious()) |
| return RedeclLink.getNext(); |
| return 0; |
| } |
| const decl_type *getPreviousDeclaration() const { |
| return const_cast<decl_type *>( |
| static_cast<const decl_type*>(this))->getPreviousDeclaration(); |
| } |
| |
| /// \brief Return the first declaration of this declaration or itself if this |
| /// is the only declaration. |
| decl_type *getFirstDeclaration() { |
| decl_type *D = static_cast<decl_type*>(this); |
| while (D->getPreviousDeclaration()) |
| D = D->getPreviousDeclaration(); |
| return D; |
| } |
| |
| /// \brief Return the first declaration of this declaration or itself if this |
| /// is the only declaration. |
| const decl_type *getFirstDeclaration() const { |
| const decl_type *D = static_cast<const decl_type*>(this); |
| while (D->getPreviousDeclaration()) |
| D = D->getPreviousDeclaration(); |
| return D; |
| } |
| |
| /// \brief Returns true if this is the first declaration. |
| bool isFirstDeclaration() const { |
| return RedeclLink.NextIsLatest(); |
| } |
| |
| /// \brief Returns the most recent (re)declaration of this declaration. |
| decl_type *getMostRecentDeclaration() { |
| return getFirstDeclaration()->RedeclLink.getNext(); |
| } |
| |
| /// \brief Returns the most recent (re)declaration of this declaration. |
| const decl_type *getMostRecentDeclaration() const { |
| return getFirstDeclaration()->RedeclLink.getNext(); |
| } |
| |
| /// \brief Set the previous declaration. If PrevDecl is NULL, set this as the |
| /// first and only declaration. |
| void setPreviousDeclaration(decl_type *PrevDecl) { |
| decl_type *First; |
| |
| if (PrevDecl) { |
| // Point to previous. Make sure that this is actually the most recent |
| // redeclaration, or we can build invalid chains. If the most recent |
| // redeclaration is invalid, it won't be PrevDecl, but we want it anyway. |
| RedeclLink = PreviousDeclLink(llvm::cast<decl_type>( |
| PrevDecl->getMostRecentDeclaration())); |
| First = PrevDecl->getFirstDeclaration(); |
| assert(First->RedeclLink.NextIsLatest() && "Expected first"); |
| } else { |
| // Make this first. |
| First = static_cast<decl_type*>(this); |
| } |
| |
| // First one will point to this one as latest. |
| First->RedeclLink = LatestDeclLink(static_cast<decl_type*>(this)); |
| } |
| |
| /// \brief Iterates through all the redeclarations of the same decl. |
| class redecl_iterator { |
| /// Current - The current declaration. |
| decl_type *Current; |
| decl_type *Starter; |
| |
| public: |
| typedef decl_type* value_type; |
| typedef decl_type* reference; |
| typedef decl_type* pointer; |
| typedef std::forward_iterator_tag iterator_category; |
| typedef std::ptrdiff_t difference_type; |
| |
| redecl_iterator() : Current(0) { } |
| explicit redecl_iterator(decl_type *C) : Current(C), Starter(C) { } |
| |
| reference operator*() const { return Current; } |
| pointer operator->() const { return Current; } |
| |
| redecl_iterator& operator++() { |
| assert(Current && "Advancing while iterator has reached end"); |
| // Get either previous decl or latest decl. |
| decl_type *Next = Current->RedeclLink.getNext(); |
| Current = (Next != Starter ? Next : 0); |
| return *this; |
| } |
| |
| redecl_iterator operator++(int) { |
| redecl_iterator tmp(*this); |
| ++(*this); |
| return tmp; |
| } |
| |
| friend bool operator==(redecl_iterator x, redecl_iterator y) { |
| return x.Current == y.Current; |
| } |
| friend bool operator!=(redecl_iterator x, redecl_iterator y) { |
| return x.Current != y.Current; |
| } |
| }; |
| |
| /// \brief Returns iterator for all the redeclarations of the same decl. |
| /// It will iterate at least once (when this decl is the only one). |
| redecl_iterator redecls_begin() const { |
| return redecl_iterator(const_cast<decl_type*>( |
| static_cast<const decl_type*>(this))); |
| } |
| redecl_iterator redecls_end() const { return redecl_iterator(); } |
| |
| friend class PCHDeclReader; |
| friend class ASTDeclWriter; |
| }; |
| |
| } |
| |
| #endif |