Index: test/Sema/deprecated.c
===================================================================
--- test/Sema/deprecated.c	(revision 0)
+++ test/Sema/deprecated.c	(revision 0)
@@ -0,0 +1,25 @@
+// RUN: clang %s -verify -fsyntax-only
+
+int f() __attribute__((deprecated));
+void g() __attribute__((deprecated));
+void g();
+
+void z() __attribute__((bogusattr)); // expected-warning {{'bogusattr' attribute ignored}}
+
+extern int var __attribute__((deprecated));
+
+int a() {
+  int (*ptr)() = f; // expected-warning {{'f' is deprecated}}
+  f(); // expected-warning {{'f' is deprecated}}
+
+  // test if attributes propagate to functions
+  g(); // expected-warning {{'g' is deprecated}}
+
+  return var; // expected-warning {{'var' is deprecated}}
+}
+
+// test if attributes propagate to variables
+extern int var;
+int w() {
+	return var; // expected-warning {{'var' is deprecated}}
+}
Index: include/clang/Basic/DiagnosticKinds.def
===================================================================
--- include/clang/Basic/DiagnosticKinds.def	(revision 47752)
+++ include/clang/Basic/DiagnosticKinds.def	(working copy)
@@ -617,6 +617,8 @@
      "unexpected type name '%0': expected expression")
 DIAG(err_undeclared_var_use, ERROR,
      "use of undeclared identifier '%0'")
+DIAG(warn_deprecated, WARNING,
+     "'%0' is deprecated")
 DIAG(err_redefinition, ERROR,
      "redefinition of '%0'")
 DIAG(err_static_non_static, ERROR,
Index: include/clang/AST/Attr.h
===================================================================
--- include/clang/AST/Attr.h	(revision 47752)
+++ include/clang/AST/Attr.h	(working copy)
@@ -26,7 +26,8 @@
     Aligned,
     Packed,
     Annotate,
-    NoReturn
+    NoReturn,
+    Deprecated
   };
     
 private:
@@ -107,6 +108,16 @@
   static bool classof(const NoReturnAttr *A) { return true; }
 };
 
+class DeprecatedAttr : public Attr {
+public:
+  DeprecatedAttr() : Attr(Deprecated) {}
+
+  // Implement isa/cast/dyncast/etc.
+
+  static bool classof(const Attr *A) { return A->getKind() == Deprecated; }
+  static bool classof(const DeprecatedAttr *A) { return true; }
+};
+
 }  // end namespace clang
 
 #endif
Index: include/clang/Parse/AttributeList.h
===================================================================
--- include/clang/Parse/AttributeList.h	(revision 47752)
+++ include/clang/Parse/AttributeList.h	(working copy)
@@ -49,7 +49,8 @@
     AT_aligned,
     AT_packed,
     AT_annotate,
-    AT_noreturn
+    AT_noreturn,
+    AT_deprecated
   };
   
   IdentifierInfo *getName() const { return AttrName; }
Index: Sema/SemaExpr.cpp
===================================================================
--- Sema/SemaExpr.cpp	(revision 47752)
+++ Sema/SemaExpr.cpp	(working copy)
@@ -100,6 +100,12 @@
     }
   }
   if (ValueDecl *VD = dyn_cast<ValueDecl>(D)) {
+
+    // check if referencing an identifier with __attribute__((deprecated))
+    if (VD->getAttr<DeprecatedAttr>()) {
+      Diag(Loc, diag::warn_deprecated, VD->getName());
+    }
+
     // Only create DeclRefExpr's for valid Decl's.
     if (VD->isInvalidDecl())
       return true;
Index: Sema/SemaDecl.cpp
===================================================================
--- Sema/SemaDecl.cpp	(revision 47752)
+++ Sema/SemaDecl.cpp	(working copy)
@@ -255,6 +255,8 @@
     Diag(OldD->getLocation(), diag::err_previous_definition);
     return New;
   }
+
+  // FIXME: propagate old Attrs to the New decl
   
   QualType OldQType = Old->getCanonicalType();
   QualType NewQType = New->getCanonicalType();
@@ -1778,6 +1780,9 @@
       vDecl->setType(newType);
     }
     break;
+  case AttributeList::AT_deprecated:
+    New->addAttr(new DeprecatedAttr());
+    break;
   case AttributeList::AT_aligned:
     HandleAlignedAttribute(New, Attr);
     break;
@@ -1791,7 +1796,7 @@
     HandleNoReturnAttribute(New, Attr);
     break;
   default:
-    // FIXME: add other attributes...
+    Diag(Attr->getLoc(), diag::warn_attribute_ignored, Attr->getName()->getName());
     break;
   }
 }
Index: Parse/AttributeList.cpp
===================================================================
--- Parse/AttributeList.cpp	(revision 47752)
+++ Parse/AttributeList.cpp	(working copy)
@@ -61,7 +61,10 @@
     if (!memcmp(Str, "annotate", 8)) return AT_annotate;
     if (!memcmp(Str, "noreturn", 8)) return AT_noreturn;
     break;
-  case 11:   
+  case 10:
+    if (!memcmp(Str, "deprecated", 10)) return AT_deprecated;
+    break;
+  case 11:
     if (!memcmp(Str, "vector_size", 11)) return AT_vector_size;
     break;
   case 13: