C++ PATCH for c++/33911 (-Wdeprecated and templates)

[Jason Merrill <jason at redhat dot com>]

We weren't warning properly about deprecated class templates because we 
were treating the deprecated attribute as a late template attribute, to 
be applied at instantiation time.  But it applies to the template 
itself, and we should warn about uses of the template as a template 
template argument as well as about uses of specializations.

To avoid regressions in the libstdc++ testsuite I've suppressed 
-Wdeprecated-declarations within two files that define deprecated 
interfaces.

Tested x86_64-pc-linux-gnu, applying to trunk.

commit eda97df89ef9538ae00ffefd76cc0a49aa0e2502
Author: Jason Merrill <jason@redhat.com>
Date:   Tue Nov 11 10:58:54 2014 -0500

    	PR c++/33911
    gcc/cp/
    	* call.c (build_call_a): Don't warn_deprecated_use here.
    	(build_over_call): Or here.
    	* decl2.c (mark_used): Do it here.
    	(is_late_template_attribute): Attribute deprecated is not deferred.
    	(cplus_decl_attributes): Propagate TREE_DEPRECATED out to the template.
    	* parser.c (cp_parser_template_name): Warn about deprecated template.
    	(cp_parser_template_argument): Likewise.
    libstdc++-v3/
    	* include/backward/binders.h: Suppress -Wdeprecated-declarations.
    	* include/ext/array_allocator.h: Likewise.

diff --git a/gcc/cp/call.c b/gcc/cp/call.c
index 06162aa..c180890 100644
--- a/gcc/cp/call.c
+++ b/gcc/cp/call.c
@@ -387,8 +387,6 @@ build_call_a (tree function, int n, tree *argarray)
       mark_used (decl);
     }
 
-  if (decl && TREE_DEPRECATED (decl))
-    warn_deprecated_use (decl, NULL_TREE);
   require_complete_eh_spec_types (fntype, decl);
 
   TREE_HAS_CONSTRUCTOR (function) = (decl && DECL_CONSTRUCTOR_P (decl));
@@ -7447,11 +7445,6 @@ build_over_call (struct z_candidate *cand, int flags, tsubst_flags_t complain)
 				ba_any, NULL, complain);
       gcc_assert (binfo && binfo != error_mark_node);
 
-      /* Warn about deprecated virtual functions now, since we're about
-	 to throw away the decl.  */
-      if (TREE_DEPRECATED (fn))
-	warn_deprecated_use (fn, NULL_TREE);
-
       argarray[0] = build_base_path (PLUS_EXPR, argarray[0], binfo, 1,
 				     complain);
       if (TREE_SIDE_EFFECTS (argarray[0]))
diff --git a/gcc/cp/decl2.c b/gcc/cp/decl2.c
index fb8d0c8..f3b94a9 100644
--- a/gcc/cp/decl2.c
+++ b/gcc/cp/decl2.c
@@ -1204,9 +1204,9 @@ is_late_template_attribute (tree attr, tree decl)
       /* Also defer most attributes on dependent types.  This is not
 	 necessary in all cases, but is the better default.  */
       else if (dependent_type_p (type)
-	       /* But attributes abi_tag and visibility specifically apply
-		  to templates.  */
+	       /* But some attributes specifically apply to templates.  */
 	       && !is_attribute_p ("abi_tag", name)
+	       && !is_attribute_p ("deprecated", name)
 	       && !is_attribute_p ("visibility", name))
 	return true;
       else
@@ -1482,6 +1482,17 @@ cplus_decl_attributes (tree *decl, tree attributes, int flags)
 
   if (TREE_CODE (*decl) == TYPE_DECL)
     SET_IDENTIFIER_TYPE_VALUE (DECL_NAME (*decl), TREE_TYPE (*decl));
+
+  /* Propagate deprecation out to the template.  */
+  if (TREE_DEPRECATED (*decl))
+    if (tree ti = get_template_info (*decl))
+      {
+	tree tmpl = TI_TEMPLATE (ti);
+	tree pattern = (TYPE_P (*decl) ? TREE_TYPE (tmpl)
+			: DECL_TEMPLATE_RESULT (tmpl));
+	if (*decl == pattern)
+	  TREE_DEPRECATED (tmpl) = true;
+      }
 }
 
 /* Walks through the namespace- or function-scope anonymous union
@@ -4891,6 +4902,10 @@ mark_used (tree decl, tsubst_flags_t complain)
       return false;
     }
 
+  if (TREE_DEPRECATED (decl) && (complain & tf_warning)
+      && deprecated_state != DEPRECATED_SUPPRESS)
+    warn_deprecated_use (decl, NULL_TREE);
+
   /* We can only check DECL_ODR_USED on variables or functions with
      DECL_LANG_SPECIFIC set, and these are also the only decls that we
      might need special handling for.  */
diff --git a/gcc/cp/parser.c b/gcc/cp/parser.c
index 3eff5fa..b106f3b 100644
--- a/gcc/cp/parser.c
+++ b/gcc/cp/parser.c
@@ -13959,7 +13959,11 @@ cp_parser_template_name (cp_parser* parser,
 
   /* If DECL is a template, then the name was a template-name.  */
   if (TREE_CODE (decl) == TEMPLATE_DECL)
-    ;
+    {
+      if (TREE_DEPRECATED (decl)
+	  && deprecated_state != DEPRECATED_SUPPRESS)
+	warn_deprecated_use (decl, NULL_TREE);
+    }
   else
     {
       tree fn = NULL_TREE;
@@ -14193,7 +14197,11 @@ cp_parser_template_argument (cp_parser* parser)
 	cp_parser_error (parser, "expected template-name");
     }
   if (cp_parser_parse_definitely (parser))
-    return argument;
+    {
+      if (TREE_DEPRECATED (argument))
+	warn_deprecated_use (argument, NULL_TREE);
+      return argument;
+    }
   /* It must be a non-type argument.  There permitted cases are given
      in [temp.arg.nontype]:
 
diff --git a/gcc/testsuite/g++.dg/ext/attr-deprecated-1.C b/gcc/testsuite/g++.dg/ext/attr-deprecated-1.C
new file mode 100644
index 0000000..31a7690
--- /dev/null
+++ b/gcc/testsuite/g++.dg/ext/attr-deprecated-1.C
@@ -0,0 +1,15 @@
+// PR c++/33911
+
+template<typename T> struct __attribute__ ((deprecated)) S {};
+S<int> s;			// { dg-warning "deprecated" }
+
+template <template <class> class T> struct A { };
+A<S> a;				// { dg-warning "deprecated" }
+
+template <class T> void f() __attribute__ ((deprecated));
+
+int main()
+{
+  f<int>();			// { dg-warning "deprecated" }
+  void (*p)() = f<char>;	// { dg-warning "deprecated" }
+}
diff --git a/libstdc++-v3/include/backward/binders.h b/libstdc++-v3/include/backward/binders.h
index bda52ed..70f8f21 100644
--- a/libstdc++-v3/include/backward/binders.h
+++ b/libstdc++-v3/include/backward/binders.h
@@ -56,6 +56,10 @@
 #ifndef _BACKWARD_BINDERS_H
 #define _BACKWARD_BINDERS_H 1
 
+// Suppress deprecated warning for this file.
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
+
 namespace std _GLIBCXX_VISIBILITY(default)
 {
 _GLIBCXX_BEGIN_NAMESPACE_VERSION
@@ -173,4 +177,6 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 _GLIBCXX_END_NAMESPACE_VERSION
 } // namespace
 
+#pragma GCC diagnostic pop
+
 #endif /* _BACKWARD_BINDERS_H */
diff --git a/libstdc++-v3/include/ext/array_allocator.h b/libstdc++-v3/include/ext/array_allocator.h
index f807495..58cf35f 100644
--- a/libstdc++-v3/include/ext/array_allocator.h
+++ b/libstdc++-v3/include/ext/array_allocator.h
@@ -38,6 +38,10 @@
 #include <type_traits>
 #endif
 
+// Suppress deprecated warning for this file.
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
+
 namespace __gnu_cxx _GLIBCXX_VISIBILITY(default)
 {
 _GLIBCXX_BEGIN_NAMESPACE_VERSION
@@ -171,4 +175,6 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 _GLIBCXX_END_NAMESPACE_VERSION
 } // namespace
 
+#pragma GCC diagnostic pop
+
 #endif