Add QualifiedDeclRefExpr, which retains additional source-location

information for declarations that were referenced via a qualified-id,
e.g., N::C::value. We keep track of the location of the start of the
nested-name-specifier. Note that the difference between
QualifiedDeclRefExpr and DeclRefExpr does have an effect on the
semantics of function calls in two ways:
  1) The use of a qualified-id instead of an unqualified-id suppresses
     argument-dependent lookup
  2) If the name refers to a virtual function, the qualified-id
  version will call the function determined statically while the
  unqualified-id version will call the function determined dynamically
  (by looking up the appropriate function in the vtable).

Neither of these features is implemented yet, but we do print out
qualified names for QualifiedDeclRefExprs as part of the AST printing.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@61789 91177308-0d34-0410-b5e6-96231b3b80d8

4 files changed, 37 insertions, 1 deletions

diff --git a/include/clang/AST/Expr.h b/include/clang/AST/Expr.h
index 62a93b51e8..0490aab200 100644
--- a/include/clang/AST/Expr.h
+++ b/include/clang/AST/Expr.h
@@ -273,9 +273,15 @@ class DeclRefExpr : public Expr {
   SourceLocation Loc;
 
 protected:
+  // FIXME: Eventually, this constructor will go away and all subclasses
+  // will have to provide the type- and value-dependent flags.
   DeclRefExpr(StmtClass SC, NamedDecl *d, QualType t, SourceLocation l) :
     Expr(SC, t), D(d), Loc(l) {}
 
+  DeclRefExpr(StmtClass SC, NamedDecl *d, QualType t, SourceLocation l, bool TD,
+              bool VD) :
+    Expr(SC, t, TD, VD), D(d), Loc(l) {}
+
 public:
   // FIXME: Eventually, this constructor will go away and all clients
   // will have to provide the type- and value-dependent flags.
@@ -294,7 +300,8 @@ public:
   
   static bool classof(const Stmt *T) { 
     return T->getStmtClass() == DeclRefExprClass ||
-           T->getStmtClass() == CXXConditionDeclExprClass; 
+           T->getStmtClass() == CXXConditionDeclExprClass ||
+           T->getStmtClass() == QualifiedDeclRefExprClass; 
   }
   static bool classof(const DeclRefExpr *) { return true; }
   
diff --git a/include/clang/AST/ExprCXX.h b/include/clang/AST/ExprCXX.h
index 37436575a2..a9ff1546e9 100644
--- a/include/clang/AST/ExprCXX.h
+++ b/include/clang/AST/ExprCXX.h
@@ -747,6 +747,33 @@ public:
   static UnaryTypeTraitExpr *CreateImpl(llvm::Deserializer& D, ASTContext& C);
 };
 
+/// QualifiedDeclRefExpr - A reference to a declared variable,
+/// function, enum, etc., that includes a qualification, e.g.,
+/// "N::foo".
+class QualifiedDeclRefExpr : public DeclRefExpr {
+  /// NestedNameLoc - The location of the beginning of the
+  /// nested-name-specifier that qualifies this declaration.
+  SourceLocation NestedNameLoc;
+
+public:
+  QualifiedDeclRefExpr(NamedDecl *d, QualType t, SourceLocation l, bool TD, 
+                       bool VD, SourceLocation nnl)
+    : DeclRefExpr(QualifiedDeclRefExprClass, d, t, l, TD, VD), 
+      NestedNameLoc(nnl) { }
+
+  virtual SourceRange getSourceRange() const { 
+    return SourceRange(NestedNameLoc, getLocation()); 
+  }
+
+  static bool classof(const Stmt *T) {
+    return T->getStmtClass() == QualifiedDeclRefExprClass;
+  }
+  static bool classof(const QualifiedDeclRefExpr *) { return true; }
+
+  virtual void EmitImpl(llvm::Serializer& S) const;
+  static QualifiedDeclRefExpr* CreateImpl(llvm::Deserializer& D, ASTContext& C);
+};
+
 }  // end namespace clang
 
 #endif
diff --git a/include/clang/AST/StmtNodes.def b/include/clang/AST/StmtNodes.def
index 7bd378220b..26d1e89637 100644
--- a/include/clang/AST/StmtNodes.def
+++ b/include/clang/AST/StmtNodes.def
@@ -114,6 +114,7 @@ STMT(CXXNewExpr             , Expr)
 STMT(CXXDeleteExpr          , Expr)
 STMT(CXXDependentNameExpr   , Expr)
 STMT(UnaryTypeTraitExpr     , Expr)
+STMT(QualifiedDeclRefExpr   , DeclRefExpr)
 
 // Obj-C Expressions.
 STMT(ObjCStringLiteral    , Expr)
diff --git a/include/clang/Basic/SourceManager.h b/include/clang/Basic/SourceManager.h
index 175c40488c..5185aa1655 100644
--- a/include/clang/Basic/SourceManager.h
+++ b/include/clang/Basic/SourceManager.h
@@ -49,6 +49,7 @@ namespace SrcMgr {
   /// ContentCache - Once instance of this struct is kept for every file
   ///  loaded or used.  This object owns the MemoryBuffer object.
   class ContentCache {
+  public: 
     /// Buffer - The actual buffer containing the characters from the input
     /// file.  This is owned by the ContentCache object.
     const llvm::MemoryBuffer* Buffer;