Keep track of whether declararions were loaded from a precompiled

header or not via a new "PCHLevel" field in Decl. We currently use
this information to help CIndex filter out declarations that came from
a precompiled header (rather than from an AST file). Further down the
road, it can be used to help implement multi-level precompiled
headers.

llvm-svn: 84267

3 files changed, 51 insertions, 6 deletions

diff --git a/clang/include/clang-c/Index.h b/clang/include/clang-c/Index.h
index 3e7ceb3d794..b80cd47e01f 100644
--- a/clang/include/clang-c/Index.h
+++ b/clang/include/clang-c/Index.h
@@ -117,6 +117,17 @@ CXTranslationUnit clang_createTranslationUnitFromSourceFile(
 );
 void clang_disposeTranslationUnit(CXTranslationUnit);
 
+/**
+ * \brief Indicate to Clang that it should only enumerate "local" declarations
+ * when loading any new translation units.
+ *
+ * A "local" declaration is one that belongs in the translation unit itself and
+ * not in a precompiled header that was used by the translation unit.
+ *
+ * FIXME: Remove this hook.
+ */
+void clang_wantOnlyLocalDeclarations(CXIndex);
+  
 /*
    Usage: clang_loadTranslationUnit(). Will load the toplevel declarations
    within a translation unit, issuing a 'callback' for each one.
diff --git a/clang/include/clang/AST/DeclBase.h b/clang/include/clang/AST/DeclBase.h
index 9e88871565f..10db7030db1 100644
--- a/clang/include/clang/AST/DeclBase.h
+++ b/clang/include/clang/AST/DeclBase.h
@@ -166,6 +166,15 @@ private:
   bool Used : 1;
 
 protected:
+  /// Access - Used by C++ decls for the access specifier.
+  // NOTE: VC++ treats enums as signed, avoid using the AccessSpecifier enum
+  unsigned Access : 2;
+  friend class CXXClassMemberWrapper;
+  
+  // PCHLevel - the "level" of precompiled header/AST file from which this
+  // declaration was built.
+  unsigned PCHLevel : 2;
+  
   /// IdentifierNamespace - This specifies what IDNS_* namespace this lives in.
   unsigned IdentifierNamespace : 16;
 
@@ -177,16 +186,13 @@ private:
 #endif
 
 protected:
-  /// Access - Used by C++ decls for the access specifier.
-  // NOTE: VC++ treats enums as signed, avoid using the AccessSpecifier enum
-  unsigned Access : 2;
-  friend class CXXClassMemberWrapper;
 
   Decl(Kind DK, DeclContext *DC, SourceLocation L)
     : NextDeclInContext(0), DeclCtx(DC),
       Loc(L), DeclKind(DK), InvalidDecl(0),
       HasAttrs(false), Implicit(false), Used(false),
-      IdentifierNamespace(getIdentifierNamespaceForKind(DK)), Access(AS_none) {
+      Access(AS_none), PCHLevel(0),
+      IdentifierNamespace(getIdentifierNamespaceForKind(DK)) {
     if (Decl::CollectingStats()) addDeclKind(DK);
   }
 
@@ -274,6 +280,26 @@ public:
   bool isUsed() const { return Used; }
   void setUsed(bool U = true) { Used = U; }
 
+  /// \brief Retrieve the level of precompiled header from which this
+  /// declaration was generated.
+  ///
+  /// The PCH level of a declaration describes where the declaration originated
+  /// from. A PCH level of 0 indicates that the declaration was not from a 
+  /// precompiled header. A PCH level of 1 indicates that the declaration was
+  /// from a top-level precompiled header; 2 indicates that the declaration 
+  /// comes from a precompiled header on which the top-level precompiled header
+  /// depends, and so on. 
+  unsigned getPCHLevel() const { return PCHLevel; }
+
+  /// \brief The maximum PCH level that any declaration may have.
+  static const unsigned MaxPCHLevel = 3;
+  
+  /// \brief Set the PCH level of this declaration.
+  void setPCHLevel(unsigned Level) { 
+    assert(Level < MaxPCHLevel && "PCH level exceeds the maximum");
+    PCHLevel = Level;
+  }
+  
   unsigned getIdentifierNamespace() const {
     return IdentifierNamespace;
   }
diff --git a/clang/include/clang/Frontend/ASTUnit.h b/clang/include/clang/Frontend/ASTUnit.h
index c1a0ebb559c..0ce473f2af5 100644
--- a/clang/include/clang/Frontend/ASTUnit.h
+++ b/clang/include/clang/Frontend/ASTUnit.h
@@ -40,6 +40,11 @@ class ASTUnit {
   llvm::OwningPtr<ASTContext>       Ctx;
   bool                              tempFile;
   
+  // OnlyLocalDecls - when true, walking this AST should only visit declarations
+  // that come from the AST itself, not from included precompiled headers.
+  // FIXME: This is temporary; eventually, CIndex will always do this.
+  bool                              OnlyLocalDecls;
+  
   ASTUnit(const ASTUnit&); // DO NOT IMPLEMENT
   ASTUnit &operator=(const ASTUnit &); // DO NOT IMPLEMENT
   ASTUnit(Diagnostic &_Diag);
@@ -65,6 +70,8 @@ public:
 
   void unlinkTemporaryFile() { tempFile = true; }
   
+  bool getOnlyLocalDecls() const { return OnlyLocalDecls; }
+  
   /// \brief Create a ASTUnit from a PCH file.
   ///
   /// \param Filename - The PCH file to load.
@@ -80,7 +87,8 @@ public:
   static ASTUnit *LoadFromPCHFile(const std::string &Filename,
                                   Diagnostic &Diags,
                                   FileManager &FileMgr,
-                                  std::string *ErrMsg = 0);
+                                  std::string *ErrMsg = 0,
+                                  bool OnlyLocalDecls = false);
 };
 
 } // namespace clang