Introduce the 'Index' library.

Its purpose is to provide the basic infrastructure for cross-translation-unit analysis like indexing, refactoring, etc.

Currently it is very "primitive" and with no type-names support. It can provide functionality like
"show me all references of this function from these translation units".

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@74802 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 70 insertions, 0 deletions

diff --git a/include/clang/Index/Entity.h b/include/clang/Index/Entity.h
new file mode 100644
index 0000000000..8caaeb870f
--- /dev/null
+++ b/include/clang/Index/Entity.h
@@ -0,0 +1,70 @@
+//===--- Entity.h - Cross-translation-unit "token" for decls ----*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+//  Entity is a ASTContext-independent way to refer to declarations that are
+//  visible across translation units.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_INDEX_ENTITY_H
+#define LLVM_CLANG_INDEX_ENTITY_H
+
+#include "llvm/ADT/FoldingSet.h"
+
+namespace clang {
+  class ASTContext;
+  class Decl;
+
+namespace idx {
+  class Program;
+
+/// \brief A ASTContext-independent way to refer to declarations that are
+/// visible across translation units.
+///
+/// Entity is basically the link for declarations that are semantically the same
+/// in multiple ASTContexts. A client will convert a Decl into an Entity and
+/// later use that Entity to find the "same" Decl into another ASTContext.
+///
+/// An Entity may only refer to declarations that can be visible by multiple
+/// translation units, e.g. a static function cannot have an Entity associated
+/// with it.
+///
+/// Entities are uniqued so pointer equality can be used (note that the same
+/// Program object should be used when getting Entities).
+///
+class Entity : public llvm::FoldingSetNode {
+public:
+  /// \brief Find the Decl that can be referred to by this entity.
+  Decl *getDecl(ASTContext &AST);
+
+  /// \brief Get an Entity associated with the given Decl.
+  /// \returns Null if an Entity cannot refer to this Decl.
+  static Entity *get(Decl *D, Program &Prog);
+
+  void Profile(llvm::FoldingSetNodeID &ID) const {
+    Profile(ID, Parent, Id);
+  }
+  static void Profile(llvm::FoldingSetNodeID &ID, Entity *Parent, void *Id) {
+    ID.AddPointer(Parent);
+    ID.AddPointer(Id);
+  }
+  
+private:
+  Entity *Parent;
+  void *Id;
+  
+  Entity(Entity *parent, void *id) : Parent(parent), Id(id) { }
+  friend class EntityGetter;
+};
+  
+} // namespace idx
+
+} // namespace clang
+
+#endif