PATCH: PR fortran/33375: ICE (segfault) gfortran.dg/common_6.f90

[H.J. Lu]

We read freed memory when processing common block symbols whose memory
has been freed before when we rejected it.  This patch frees common
tree on syntax error. Tested on Linux/ia32, Linux/Intel64 and
Linux/ia64 without regressions.


H.J.
---
2008-01-08  H.J. Lu  <hongjiu.lu@intel.com>

	PR fortran/33375
	* symbol.c (free_common_tree): Renamed to ...
	(gfc_free_common_tree): This.  Remove static.
	(gfc_free_namespace): Updated.

	* gfortran.h (gfc_free_common_tree): New.

	* match.c (gfc_match_common): Call gfc_free_common_tree () with
	gfc_current_ns->common_root and set gfc_current_ns->common_root
	to NULL on syntax error.

Index: gcc/fortran/symbol.c
===================================================================
--- gcc/fortran/symbol.c	(revision 131362)
+++ gcc/fortran/symbol.c	(working copy)
@@ -2726,14 +2726,14 @@ gfc_commit_symbol (gfc_symbol *sym)
 /* Recursive function that deletes an entire tree and all the common
    head structures it points to.  */
 
-static void
-free_common_tree (gfc_symtree * common_tree)
+void
+gfc_free_common_tree (gfc_symtree * common_tree)
 {
   if (common_tree == NULL)
     return;
 
-  free_common_tree (common_tree->left);
-  free_common_tree (common_tree->right);
+  gfc_free_common_tree (common_tree->left);
+  gfc_free_common_tree (common_tree->right);
 
   gfc_free (common_tree);
 }  
@@ -2863,7 +2863,7 @@ gfc_free_namespace (gfc_namespace *ns)
 
   free_sym_tree (ns->sym_root);
   free_uop_tree (ns->uop_root);
-  free_common_tree (ns->common_root);
+  gfc_free_common_tree (ns->common_root);
 
   for (cl = ns->cl_list; cl; cl = cl2)
     {
Index: gcc/fortran/gfortran.h
===================================================================
--- gcc/fortran/gfortran.h	(revision 131362)
+++ gcc/fortran/gfortran.h	(working copy)
@@ -2137,6 +2137,7 @@ int gfc_symbols_could_alias (gfc_symbol 
 void gfc_undo_symbols (void);
 void gfc_commit_symbols (void);
 void gfc_commit_symbol (gfc_symbol *);
+void gfc_free_common_tree (gfc_symtree *);
 void gfc_free_namespace (gfc_namespace *);
 
 void gfc_symbol_init_2 (void);
Index: gcc/fortran/match.c
===================================================================
--- gcc/fortran/match.c	(revision 131362)
+++ gcc/fortran/match.c	(working copy)
@@ -2951,6 +2951,8 @@ done:
   return MATCH_YES;
 
 syntax:
+  gfc_free_common_tree (gfc_current_ns->common_root);
+  gfc_current_ns->common_root = NULL;
   gfc_syntax_error (ST_COMMON);
 
 cleanup: