re PR c/53702 (ICE with -Wall and nested functions and unused typedef)

	PR c/53702

	* c-decl.c (c_push_function_context): Restore the behavior to reuse
	the language function allocated for -Wunused-local-typedefs.
	(c_pop_function_context): If necessary, clear the language function
	created in c_push_function_context.  Always clear out the
	x_cur_stmt_list field of the restored language function.

testsuite/
	* gcc.dg/Wunused-local-typedefs.c: New testcase.

From-SVN: r188860

gcc/ChangeLog

+2012-06-21  Meador Inge  <meadori@codesourcery.com>
+
+	PR c/53702
+	* c-decl.c (c_push_function_context): Restore the behavior to reuse
+	the language function allocated for -Wunused-local-typedefs.
+	(c_pop_function_context): If necessary, clear the language function
+	created in c_push_function_context.  Always clear out the
+	x_cur_stmt_list field of the restored language function.
+
 2012-06-21   Sterling Augustine  <saugustine@google.com>
         Cary Coutant  <ccoutant@google.com>
 

gcc/c-decl.c

@@ -8579,9 +8579,11 @@ check_for_loop_decls (location_t loc, bool turn_off_iso_c99_error)
 void
 c_push_function_context (void)
 {
-  struct language_function *p;
-  p = ggc_alloc_language_function ();
-  cfun->language = p;
+  struct language_function *p = cfun->language;
+  /* cfun->language might have been already allocated by the use of
+     -Wunused-local-typedefs.  In that case, just re-use it.  */
+  if (p == NULL)
+    cfun->language = p = ggc_alloc_cleared_language_function ();
 
   p->base.x_stmt_tree = c_stmt_tree;
   c_stmt_tree.x_cur_stmt_list
@@ -8607,7 +8609,12 @@ c_pop_function_context (void)
 
   pop_function_context ();
   p = cfun->language;
-  cfun->language = NULL;
+
+  /* When -Wunused-local-typedefs is in effect, cfun->languages is
+     used to store data throughout the life time of the current cfun,
+     So don't deallocate it.  */
+  if (!warn_unused_local_typedefs)
+    cfun->language = NULL;
 
   if (DECL_STRUCT_FUNCTION (current_function_decl) == 0
       && DECL_SAVED_TREE (current_function_decl) == NULL_TREE)
@@ -8620,6 +8627,7 @@ c_pop_function_context (void)
     }
 
   c_stmt_tree = p->base.x_stmt_tree;
+  p->base.x_stmt_tree.x_cur_stmt_list = NULL;
   c_break_label = p->x_break_label;
   c_cont_label = p->x_cont_label;
   c_switch_stack = p->x_switch_stack;

gcc/testsuite/ChangeLog

+2012-06-21  Meador Inge  <meadori@codesourcery.com>
+
+	PR c/53702
+	* gcc.dg/Wunused-local-typedefs.c: New testcase.
+
 2012-06-21  Steven Bosscher  <steven@gcc.gnu.org>
 
 	* testsuite/gcc.dg/pch/ident-1.c: New test.

gcc/testsuite/gcc.dg/Wunused-local-typedefs.c

+/*  Origin PR c/53702
+    { dg-options "-Wunused-local-typedefs" }
+    { dg-do compile }
+*/
+
+/* Only test nested functions for C.  More tests that work for C and C++
+   can be found in c-c++-common.
+*/
+
+void
+test0 ()
+{
+  typedef int foo; /* { dg-warning "locally defined but not used" } */
+  void f ()
+  {
+  }
+}
+
+void
+test1 ()
+{
+  void f ()
+  {
+    typedef int foo; /* { dg-warning "locally defined but not used" } */
+  }
+}
+
+
+void
+test2 ()
+{
+  void f ()
+  {
+  }
+  typedef int foo; /* { dg-warning "locally defined but not used" } */
+}