[svn:parrot] r41242 - trunk/compilers/imcc

[chromatic at svn.parrot.org]

Author: chromatic
Date: Sat Sep 12 21:20:12 2009
New Revision: 41242
URL: https://trac.parrot.org/parrot/changeset/41242

Log:
[IMCC] Avoided a memory corruption error when switching namespaces to the
*current* namespace in PIR: IMCC assumed that freeing the old SymReg was always
valid.  This isn't the case if it's the *same* namespace and the *same* SymReg.
See TT #992, filed by Jonathan Leto.

Modified:
   trunk/compilers/imcc/parser_util.c

Modified: trunk/compilers/imcc/parser_util.c
==============================================================================
--- trunk/compilers/imcc/parser_util.c	Sat Sep 12 20:23:25 2009	(r41241)
+++ trunk/compilers/imcc/parser_util.c	Sat Sep 12 21:20:12 2009	(r41242)
@@ -714,13 +714,14 @@
     }
 
     if (imc_info) {
+        SymReg *ns                  = IMCC_INFO(interp)->cur_namespace;
         IMCC_INFO(interp)           = imc_info->prev;
         mem_sys_free(imc_info);
         imc_info                    = IMCC_INFO(interp);
         IMCC_INFO(interp)->cur_unit = imc_info->last_unit;
 
-        if (IMCC_INFO(interp)->cur_namespace)
-            free_sym(IMCC_INFO(interp)->cur_namespace);
+        if (ns && ns != imc_info->cur_namespace)
+            free_sym(ns);
 
         IMCC_INFO(interp)->cur_namespace = imc_info->cur_namespace;
     }