[PATCH 1/3] Fix segfault when unwinding JIT frames using a custom reader.

[Sanjoy Das <sanjoy@playingwithpointers.com>]

Issue http://sourceware.org/bugzilla/show_bug.cgi?id=14550
---
 gdb/ChangeLog |    7 +++++++
 gdb/jit.c     |   14 ++++++++++++--
 2 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index f7808a4..0999b30 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,10 @@
+2012-11-04  Sanjoy Das <sanjoy@playingwithpointers.com>
+
+	PR gdb/14550
+
+	* jit.c (finalize_symtab): Ensure that only the global block has a
+	NULL superblock.
+
 2012-11-03  Yao Qi  <yao@codesourcery.com>
 
 	Fix PR gdb/14617.
diff --git a/gdb/jit.c b/gdb/jit.c
index 9e8f295..eff2ed6 100644
--- a/gdb/jit.c
+++ b/gdb/jit.c
@@ -724,8 +724,18 @@ finalize_symtab (struct gdb_symtab *stab, struct objfile *objfile)
        gdb_block_iter = gdb_block_iter->next)
     {
       if (gdb_block_iter->parent != NULL)
-        BLOCK_SUPERBLOCK (gdb_block_iter->real_block) =
-          gdb_block_iter->parent->real_block;
+	{
+	  /* If the plugin specifically mentioned a parent block, we
+	     use that.  */
+	  BLOCK_SUPERBLOCK (gdb_block_iter->real_block) =
+	    gdb_block_iter->parent->real_block;
+	}
+      else
+	{
+	  /* And if not, we set a default parent block.  */
+	  BLOCK_SUPERBLOCK (gdb_block_iter->real_block) =
+	    BLOCKVECTOR_BLOCK (symtab->blockvector, STATIC_BLOCK);
+	}
     }
 
   /* Free memory.  */
-- 
1.7.10.4