2011-09-12 Basile Starynkevitch <basile@starynkevitch.net>

	MELT branch merged with trunk rev 178775 using svnmerge.



git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/branches/melt-branch@178776 138bc75d-0d04-0410-961f-82ee72b054a4

4 files changed, 95 insertions, 1 deletions

diff --git a/gcc/c-family/ChangeLog b/gcc/c-family/ChangeLog
index 347d904205f..080d42ac340 100644
--- a/gcc/c-family/ChangeLog
+++ b/gcc/c-family/ChangeLog
@@ -1,3 +1,15 @@
+2011-09-08  Dodji Seketeli  <dodji@redhat.com>
+
+	PR c++/33255 - Support -Wunused-local-typedefs warning
+	* c-common.h (struct c_language_function::local_typedefs): New
+	field.
+    	(record_locally_defined_typedef, maybe_record_typedef_use)
+    	(maybe_warn_unused_local_typedefs): Declare new functions.
+	* c-common.c (record_locally_defined_typedef)
+    	(maybe_record_typedef_use)
+    	(maybe_warn_unused_local_typedefs): Define new functions.
+	* c.opt: Declare new -Wunused-local-typedefs flag.
+
 2011-09-06  Eric Botcazou  <ebotcazou@adacore.com>
 
 	PR middle-end/50266
diff --git a/gcc/c-family/c-common.c b/gcc/c-family/c-common.c
index d8028d34878..e2852b66328 100644
--- a/gcc/c-family/c-common.c
+++ b/gcc/c-family/c-common.c
@@ -6133,7 +6133,8 @@ handle_used_attribute (tree *pnode, tree name, tree ARG_UNUSED (args),
   tree node = *pnode;
 
   if (TREE_CODE (node) == FUNCTION_DECL
-      || (TREE_CODE (node) == VAR_DECL && TREE_STATIC (node)))
+      || (TREE_CODE (node) == VAR_DECL && TREE_STATIC (node))
+      || (TREE_CODE (node) == TYPE_DECL))
     {
       TREE_USED (node) = 1;
       DECL_PRESERVE_P (node) = 1;
@@ -9646,6 +9647,76 @@ record_types_used_by_current_var_decl (tree decl)
     }
 }
 
+/* If DECL is a typedef that is declared in the current function,
+   record it for the purpose of -Wunused-local-typedefs.  */
+
+void
+record_locally_defined_typedef (tree decl)
+{
+  struct c_language_function *l;
+
+  if (!warn_unused_local_typedefs
+      || cfun == NULL
+      /* if this is not a locally defined typedef then we are not
+	 interested.  */
+      || !is_typedef_decl (decl)
+      || !decl_function_context (decl))
+    return;
+
+  l = (struct c_language_function *) cfun->language;
+  VEC_safe_push (tree, gc, l->local_typedefs, decl);
+}
+
+/* If T is a TYPE_DECL declared locally, mark it as used.  */
+
+void
+maybe_record_typedef_use (tree t)
+{
+  if (!is_typedef_decl (t))
+    return;
+
+  TREE_USED (t) = true;
+}
+
+/* Warn if there are some unused locally defined typedefs in the
+   current function. */
+
+void
+maybe_warn_unused_local_typedefs (void)
+{
+  int i;
+  tree decl;
+  /* The number of times we have emitted -Wunused-local-typedefs
+     warnings.  If this is different from errorcount, that means some
+     unrelated errors have been issued.  In which case, we'll avoid
+     emitting "unused-local-typedefs" warnings.  */
+  static int unused_local_typedefs_warn_count;
+  struct c_language_function *l;
+
+  if (cfun == NULL)
+    return;
+
+  if ((l = (struct c_language_function *) cfun->language) == NULL)
+    return;
+
+  if (warn_unused_local_typedefs
+      && errorcount == unused_local_typedefs_warn_count)
+    {
+      FOR_EACH_VEC_ELT (tree, l->local_typedefs, i, decl)
+	if (!TREE_USED (decl))
+	  warning_at (DECL_SOURCE_LOCATION (decl),
+		      OPT_Wunused_local_typedefs,
+		      "typedef %qD locally defined but not used", decl);
+      unused_local_typedefs_warn_count = errorcount;
+    }
+
+  if (l->local_typedefs)
+    {
+      VEC_free (tree, gc, l->local_typedefs);
+      l->local_typedefs = NULL;
+    }
+}
+
 /* The C and C++ parsers both use vectors to hold function arguments.
    For efficiency, we keep a cache of unused vectors.  This is the
    cache.  */
diff --git a/gcc/c-family/c-common.h b/gcc/c-family/c-common.h
index 7ad82c009c8..7241d666d22 100644
--- a/gcc/c-family/c-common.h
+++ b/gcc/c-family/c-common.h
@@ -506,6 +506,10 @@ struct GTY(()) c_language_function {
   /* While we are parsing the function, this contains information
      about the statement-tree that we are building.  */
   struct stmt_tree_s x_stmt_tree;
+
+  /* Vector of locally defined typedefs, for
+     -Wunused-local-typedefs.  */
+  VEC(tree,gc) *local_typedefs;
 };
 
 #define stmt_list_stack (current_stmt_tree ()->x_cur_stmt_list)
@@ -988,6 +992,9 @@ extern void warn_for_sign_compare (location_t,
 extern void do_warn_double_promotion (tree, tree, tree, const char *, 
 				      location_t);
 extern void set_underlying_type (tree);
+extern void record_locally_defined_typedef (tree);
+extern void maybe_record_typedef_use (tree);
+extern void maybe_warn_unused_local_typedefs (void);
 extern VEC(tree,gc) *make_tree_vector (void);
 extern void release_tree_vector (VEC(tree,gc) *);
 extern VEC(tree,gc) *make_tree_vector_single (tree);
diff --git a/gcc/c-family/c.opt b/gcc/c-family/c.opt
index 617ea2d8905..e6ac5dca2ef 100644
--- a/gcc/c-family/c.opt
+++ b/gcc/c-family/c.opt
@@ -653,6 +653,10 @@ Wunsuffixed-float-constants
 C ObjC Var(warn_unsuffixed_float_constants) Warning
 Warn about unsuffixed float constants
 
+Wunused-local-typedefs
+C ObjC C++ ObjC++ Var(warn_unused_local_typedefs) Warning
+Warn about
+
 Wunused-macros
 C ObjC C++ ObjC++ Warning
 Warn about macros defined in the main file that are not used