Add first pieces of support for parsing and representing

extern "C" in C++ mode.  Patch by Mike Stump!


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@45904 91177308-0d34-0410-b5e6-96231b3b80d8

5 files changed, 49 insertions, 0 deletions

diff --git a/include/clang/AST/Decl.h b/include/clang/AST/Decl.h
index 321eb4b70c..40af7bada0 100644
--- a/include/clang/AST/Decl.h
+++ b/include/clang/AST/Decl.h
@@ -70,6 +70,7 @@ public:
          ObjCMethod,
          ObjCClass,
          ObjCForwardProtocol,
+ 	 LinkageSpec,
   
     // For each non-leaf class, we now define a mapping to the first/last member
     // of the class, to allow efficient classof.
@@ -753,6 +754,42 @@ protected:
   friend Decl* Decl::Create(llvm::Deserializer& D);
 };
 
+
+/// LinkageSpecDecl - This represents a linkage specification.  For example:
+///   extern "C" void foo();
+///
+class LinkageSpecDecl : public Decl {
+public:
+  /// LanguageIDs - Used to represent the language in a linkage
+  /// specification.  The values are part of the serialization abi for
+  /// ASTs and cannot be changed without altering that abi.  To help
+  /// ensure a stable abi for this, we choose the DW_LANG_ encodings
+  /// from the dwarf standard.
+  enum LanguageIDs { lang_c = /* DW_LANG_C */ 0x0002,
+		     lang_cxx = /* DW_LANG_C_plus_plus */ 0x0004 };
+private:
+  /// Language - The language for this linkage specification.
+  LanguageIDs Language;
+  /// D - This is the Decl of the linkage specification.
+  Decl *D;
+public:
+  LinkageSpecDecl(SourceLocation L, LanguageIDs lang, Decl *d)
+   : Decl(LinkageSpec, L), Language(lang), D(d) {}
+  
+  LanguageIDs getLanguage() const { return Language; }
+  const Decl *getDecl() const { return D; }
+  Decl *getDecl() { return D; }
+    
+  static bool classof(const Decl *D) {
+    return D->getKind() == LinkageSpec;
+  }
+  static bool classof(const LinkageSpecDecl *D) { return true; }
+  
+protected:
+  void EmitInRec(llvm::Serializer& S) const;
+  void ReadInRec(llvm::Deserializer& D);
+};
+
 }  // end namespace clang
 
 #endif
diff --git a/include/clang/Basic/DiagnosticKinds.def b/include/clang/Basic/DiagnosticKinds.def
index 1191455d74..b91c7313f1 100644
--- a/include/clang/Basic/DiagnosticKinds.def
+++ b/include/clang/Basic/DiagnosticKinds.def
@@ -537,6 +537,8 @@ DIAG(err_invalid_reference_qualifier_application, ERROR,
      "'%0' qualifier may not be applied to a reference")
 DIAG(err_declarator_need_ident, ERROR,
      "declarator requires an identifier")
+DIAG(err_bad_language, ERROR,
+     "unknown linkage language")
 
 // Attributes
 DIAG(err_attribute_wrong_number_arguments, ERROR,
diff --git a/include/clang/CodeGen/ModuleBuilder.h b/include/clang/CodeGen/ModuleBuilder.h
index 7fddcadae1..b27e3d35f5 100644
--- a/include/clang/CodeGen/ModuleBuilder.h
+++ b/include/clang/CodeGen/ModuleBuilder.h
@@ -22,6 +22,7 @@ namespace llvm {
 namespace clang {
   class ASTContext;
   class FunctionDecl;
+  class LinkageSpecDecl;
   class FileVarDecl;
   struct LangOptions;
   class Diagnostic;
@@ -37,6 +38,8 @@ namespace CodeGen {
   /// CodeGenFunction - Convert the AST node for a FunctionDecl into LLVM.
   ///
   void CodeGenFunction(CodeGenModule *Builder, FunctionDecl *D);
+
+  void CodeGenLinkageSpec(CodeGenModule *Builder, LinkageSpecDecl *LS);
   
   /// CodeGenGlobalVar - Emit the specified global variable to LLVM.
   void CodeGenGlobalVar(CodeGenModule *Builder, FileVarDecl *D);
diff --git a/include/clang/Parse/Action.h b/include/clang/Parse/Action.h
index 8b4a0c1bfd..0e5ae2a79b 100644
--- a/include/clang/Parse/Action.h
+++ b/include/clang/Parse/Action.h
@@ -154,6 +154,12 @@ public:
   virtual DeclTy *ParsedFreeStandingDeclSpec(Scope *S, DeclSpec &DS) {
     return 0;
   }
+
+  virtual DeclTy *ActOnLinkageSpec(SourceLocation Loc, SourceLocation LBrace,
+				   SourceLocation RBrace, const char *Lang,
+				   unsigned StrSize, DeclTy *D) {
+    return 0;
+  }
   
   //===--------------------------------------------------------------------===//
   // Type Parsing Callbacks.
diff --git a/include/clang/Parse/Parser.h b/include/clang/Parse/Parser.h
index c1069c25f6..508dc306ad 100644
--- a/include/clang/Parse/Parser.h
+++ b/include/clang/Parse/Parser.h
@@ -437,6 +437,7 @@ private:
   // C++ 7: Declarations [dcl.dcl]
   
   DeclTy *ParseNamespace(unsigned Context);
+  DeclTy *ParseLinkage(unsigned Context);
 
 };