-Keep a reference to the ASTContext inside the TranslationUnitDecl.

-Introduce Decl::getASTContext() which returns the reference from the TranslationUnitDecl that it is contained in.

The general idea is that Decls can point to their own ASTContext so that it is no longer required to "manually" keep track and make sure that you pass the correct ASTContext to Decls' methods, e.g. methods like Decl::getAttrs should eventually not require a ASTContext parameter.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@74434 91177308-0d34-0410-b5e6-96231b3b80d8

include/clang/AST/Decl.h

@@ -30,10 +30,15 @@ class FunctionTemplateSpecializationInfo;
   
 /// TranslationUnitDecl - The top declaration context.
 class TranslationUnitDecl : public Decl, public DeclContext {
-  TranslationUnitDecl()
+  ASTContext &Ctx;
+  
+  explicit TranslationUnitDecl(ASTContext &ctx)
     : Decl(TranslationUnit, 0, SourceLocation()),
-      DeclContext(TranslationUnit) {}
+      DeclContext(TranslationUnit),
+      Ctx(ctx) {}
 public:
+  ASTContext &getASTContext() const { return Ctx; }
+  
   static TranslationUnitDecl *Create(ASTContext &C);
   // Implement isa/cast/dyncast/etc.
   static bool classof(const Decl *D) { return D->getKind() == TranslationUnit; }

include/clang/AST/DeclBase.h

@@ -213,6 +213,13 @@ public:
   const DeclContext *getDeclContext() const {
     return const_cast<Decl*>(this)->getDeclContext();
   }
+
+  TranslationUnitDecl *getTranslationUnitDecl();
+  const TranslationUnitDecl *getTranslationUnitDecl() const {
+    return const_cast<Decl*>(this)->getTranslationUnitDecl();
+  }
+
+  ASTContext &getASTContext() const;
   
   void setAccess(AccessSpecifier AS) {
     Access = AS; 

lib/AST/Decl.cpp

@@ -41,7 +41,7 @@ void Attr::Destroy(ASTContext &C) {
  
 
 TranslationUnitDecl *TranslationUnitDecl::Create(ASTContext &C) {
-  return new (C) TranslationUnitDecl();
+  return new (C) TranslationUnitDecl(C);
 }
 
 NamespaceDecl *NamespaceDecl::Create(ASTContext &C, DeclContext *DC,

lib/AST/DeclBase.cpp

@@ -157,6 +157,22 @@ void Decl::setLexicalDeclContext(DeclContext *DC) {
   }
 }
 
+TranslationUnitDecl *Decl::getTranslationUnitDecl() {
+  DeclContext *DC = getDeclContext();
+  assert(DC && "This decl is not contained in a translation unit!");
+ 
+  while (!DC->isTranslationUnit()) {
+    DC = DC->getParent();
+    assert(DC && "This decl is not contained in a translation unit!");
+  }
+  
+  return cast<TranslationUnitDecl>(DC);
+}
+
+ASTContext &Decl::getASTContext() const {
+  return getTranslationUnitDecl()->getASTContext();  
+}
+
 unsigned Decl::getIdentifierNamespaceForKind(Kind DeclKind) {
   switch (DeclKind) {
     default: