Implement basic importing and merging of variable declarations within

the AST importer. This doesn't actually do anything (yet), because we
don't have driver logic for merging ASTs.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@95570 91177308-0d34-0410-b5e6-96231b3b80d8

4 files changed, 57 insertions, 2 deletions

diff --git a/include/clang/AST/ASTImporter.h b/include/clang/AST/ASTImporter.h
index 01ec13470e..71b6443f50 100644
--- a/include/clang/AST/ASTImporter.h
+++ b/include/clang/AST/ASTImporter.h
@@ -44,11 +44,15 @@ namespace clang {
     /// to the corresponding types in the "to" context.
     llvm::DenseMap<Type *, Type *> ImportedTypes;
     
+    /// \brief Mapping from the already-imported declarations in the "from"
+    /// context to the corresponding declarations in the "to" context.
+    llvm::DenseMap<Decl *, Decl *> ImportedDecls;
+    
   public:
     ASTImporter(ASTContext &ToContext, Diagnostic &ToDiags,
                 ASTContext &FromContext, Diagnostic &FromDiags);
     
-    ~ASTImporter();
+    virtual ~ASTImporter();
     
     /// \brief Import the given type from the "from" context into the "to"
     /// context.
@@ -126,6 +130,38 @@ namespace clang {
     /// \returns the equivalent identifier in the "to" context.
     IdentifierInfo *Import(IdentifierInfo *FromId);
 
+    /// \brief Cope with a name conflict when importing a declaration into the
+    /// given context.
+    ///
+    /// This routine is invoked whenever there is a name conflict while 
+    /// importing a declaration. The returned name will become the name of the
+    /// imported declaration. By default, the returned name is the same as the
+    /// original name, leaving the conflict unresolve such that name lookup
+    /// for this name is likely to find an ambiguity later.
+    ///
+    /// Subclasses may override this routine to resolve the conflict, e.g., by
+    /// renaming the declaration being imported.
+    ///
+    /// \param Name the name of the declaration being imported, which conflicts
+    /// with other declarations.
+    ///
+    /// \param DC the declaration context (in the "to" AST context) in which 
+    /// the name is being imported.
+    ///
+    /// \param IDNS the identifier namespace in which the name will be found.
+    ///
+    /// \param Decls the set of declarations with the same name as the
+    /// declaration being imported.
+    ///
+    /// \param NumDecls the number of conflicting declarations in \p Decls.
+    ///
+    /// \returns the name that the newly-imported declaration should have.
+    virtual DeclarationName HandleNameConflict(DeclarationName Name,
+                                               DeclContext *DC,
+                                               unsigned IDNS,
+                                               NamedDecl **Decls,
+                                               unsigned NumDecls);
+    
     /// \brief Retrieve the context that AST nodes are being imported into.
     ASTContext &getToContext() const { return ToContext; }
     
@@ -139,6 +175,16 @@ namespace clang {
     /// \brief Retrieve the diagnostics object to use to report errors within
     /// the context we're importing from.
     Diagnostic &getFromDiags() const { return FromDiags; }
+    
+    /// \brief Retrieve the mapping from declarations in the "from" context
+    /// to the already-imported declarations in the "to" context.
+    llvm::DenseMap<Decl *, Decl *> &getImportedDecls() { return ImportedDecls; }
+    
+    /// \brief Report a diagnostic in the "to" context.
+    DiagnosticBuilder ToDiag(SourceLocation Loc, unsigned DiagID);
+    
+    /// \brief Report a diagnostic in the "from" context.
+    DiagnosticBuilder FromDiag(SourceLocation Loc, unsigned DiagID);
   };
 }
 
diff --git a/include/clang/Basic/DiagnosticASTKinds.td b/include/clang/Basic/DiagnosticASTKinds.td
index f075aaaf42..d6921df0a3 100644
--- a/include/clang/Basic/DiagnosticASTKinds.td
+++ b/include/clang/Basic/DiagnosticASTKinds.td
@@ -26,4 +26,12 @@ def err_asm_empty_symbolic_operand_name : Error<
 def err_asm_invalid_operand_number : Error<
   "invalid operand number in inline asm string">;
 
+// Importing ASTs
+def err_odr_variable_type_inconsistent : Error<
+  "external variable %0 declared with incompatible types in different "
+  "translation units (%1 vs. %2)">;
+def err_odr_variable_multiple_def : Error<
+  "external variable %0 defined in multiple translation units">;
+def note_odr_value_here : Note<"declared here with type %0">;
+def note_odr_defined_here : Note<"also defined here">;
 }
diff --git a/include/clang/Basic/DiagnosticSemaKinds.td b/include/clang/Basic/DiagnosticSemaKinds.td
index d31dbd531a..496e0202eb 100644
--- a/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/include/clang/Basic/DiagnosticSemaKinds.td
@@ -2724,6 +2724,7 @@ def err_undeclared_protocol_suggest : Error<
   "cannot find protocol declaration for %0; did you mean %1?">;
 def note_base_class_specified_here : Note<
   "base class %0 specified here">;
+
 }
 
 
diff --git a/include/clang/Frontend/FrontendAction.h b/include/clang/Frontend/FrontendAction.h
index 3042767af8..29a9302c5c 100644
--- a/include/clang/Frontend/FrontendAction.h
+++ b/include/clang/Frontend/FrontendAction.h
@@ -167,7 +167,7 @@ public:
 };
 
 /// ASTFrontendAction - Abstract base class to use for AST consumer based
-/// frontend actios.
+/// frontend actions.
 class ASTFrontendAction : public FrontendAction {
   /// ExecuteAction - Implement the ExecuteAction interface by running Sema on
   /// the already initialized AST consumer.