C++/c-common PATCH for c++/35688 (wrong visibility of template instantiation)

commit 3f9fa74f7ee3f2074316bfb49fa1a09b98f78602
Author: Jason Merrill <jason@redhat.com>
Date:   Sun Nov 6 15:44:49 2011 -0500

    	PR c++/35688
    gcc/c-common/
    	* c-common.c (decl_has_visibility_attr): Split out from...
    	(c_determine_visibility): ...here.
    	* c-common.h: Declare it.
    gcc/cp/
    	* decl2.c (constrain_visibility): Check decl_has_visibility_attr
    	rather than DECL_VISIBILITY_SPECIFIED.

diff --git a/gcc/c-family/c-common.c b/gcc/c-family/c-common.c
index 5627fe1..71b3721 100644
--- a/gcc/c-family/c-common.c
+++ b/gcc/c-family/c-common.c
@@ -7043,6 +7043,22 @@  handle_visibility_attribute (tree *node, tree name, tree args,
   return NULL_TREE;
 }
 
+/* Returns true iff DECL actually has visibility specified by an attribute.
+   We check for an explicit attribute, rather than just checking
+   DECL_VISIBILITY_SPECIFIED, to distinguish the use of an attribute from
+   the use of a "#pragma GCC visibility push(...)"; in the latter case we
+   still want other considerations to be able to overrule the #pragma.  */
+
+bool
+decl_has_visibility_attr (tree decl)
+{
+  tree attrs = DECL_ATTRIBUTES (decl);
+  return (lookup_attribute ("visibility", attrs)
+	  || (TARGET_DLLIMPORT_DECL_ATTRIBUTES
+	      && (lookup_attribute ("dllimport", attrs)
+		  || lookup_attribute ("dllexport", attrs))));
+}
+
 /* Determine the ELF symbol visibility for DECL, which is either a
    variable or a function.  It is an error to use this function if a
    definition of DECL is not available in this translation unit.
@@ -7058,15 +7074,8 @@  c_determine_visibility (tree decl)
 
   /* If the user explicitly specified the visibility with an
      attribute, honor that.  DECL_VISIBILITY will have been set during
-     the processing of the attribute.  We check for an explicit
-     attribute, rather than just checking DECL_VISIBILITY_SPECIFIED,
-     to distinguish the use of an attribute from the use of a "#pragma
-     GCC visibility push(...)"; in the latter case we still want other
-     considerations to be able to overrule the #pragma.  */
-  if (lookup_attribute ("visibility", DECL_ATTRIBUTES (decl))
-      || (TARGET_DLLIMPORT_DECL_ATTRIBUTES
-	  && (lookup_attribute ("dllimport", DECL_ATTRIBUTES (decl))
-	      || lookup_attribute ("dllexport", DECL_ATTRIBUTES (decl)))))
+     the processing of the attribute.  */
+  if (decl_has_visibility_attr (decl))
     return true;
 
   /* Set default visibility to whatever the user supplied with
diff --git a/gcc/c-family/c-common.h b/gcc/c-family/c-common.h
index 7ecb57e..0b22d3d 100644
--- a/gcc/c-family/c-common.h
+++ b/gcc/c-family/c-common.h
@@ -771,6 +771,7 @@  extern void overflow_warning (location_t, tree);
 extern void warn_logical_operator (location_t, enum tree_code, tree,
 				   enum tree_code, tree, enum tree_code, tree);
 extern void check_main_parameter_types (tree decl);
+extern bool decl_has_visibility_attr (tree);
 extern bool c_determine_visibility (tree);
 extern bool same_scalar_type_ignoring_signedness (tree, tree);
 extern void mark_valid_location_for_stdc_pragma (bool);
diff --git a/gcc/cp/decl2.c b/gcc/cp/decl2.c
index 32b5c7e..4bc02bd 100644
--- a/gcc/cp/decl2.c
+++ b/gcc/cp/decl2.c
@@ -1974,8 +1974,11 @@  constrain_visibility (tree decl, int visibility)
 	    DECL_NOT_REALLY_EXTERN (decl) = 1;
 	}
     }
+  /* We check decl_has_visibility_attr rather than
+     DECL_VISIBILITY_SPECIFIED here because we want other considerations
+     to override visibility from a namespace or #pragma.  */
   else if (visibility > DECL_VISIBILITY (decl)
-	   && !DECL_VISIBILITY_SPECIFIED (decl))
+	   && !decl_has_visibility_attr (decl))
     {
       DECL_VISIBILITY (decl) = (enum symbol_visibility) visibility;
       return true;
diff --git a/gcc/testsuite/g++.dg/ext/visibility/template7.C b/gcc/testsuite/g++.dg/ext/visibility/template7.C
new file mode 100644
index 0000000..5197fb1
--- /dev/null
+++ b/gcc/testsuite/g++.dg/ext/visibility/template7.C
@@ -0,0 +1,29 @@ 
+// PR c++/35688
+// { dg-require-visibility "" }
+// { dg-options "-fvisibility=hidden" }
+
+// { dg-final { scan-hidden "_ZN1s6vectorI1AEC1Ev" } }
+// { dg-final { scan-hidden "_ZN1s3fooI1AEEvT_" } }
+
+namespace s __attribute__((visibility("default"))) {
+  template <class T>
+    class vector {
+  public:
+    vector() { }
+  };
+  template <class T>
+    void foo(T t) {
+  }
+}
+
+class A {
+public:
+  A() { }
+};
+
+s::vector<A> v;
+
+int main() {
+  A a;
+  s::foo(a);
+}