This is the mail archive of the
gcc-patches@gcc.gnu.org
mailing list for the GCC project.
Re: [google][4.6]Bug fix to function reordering linker plugin (issue5623048)
- From: Xinliang David Li <davidxl at google dot com>
- To: Sriraman Tallam <tmsriram at google dot com>
- Cc: reply at codereview dot appspotmail dot com, eraman at google dot com, gcc-patches at gcc dot gnu dot org
- Date: Thu, 2 Feb 2012 20:23:59 -0800
- Subject: Re: [google][4.6]Bug fix to function reordering linker plugin (issue5623048)
- References: <20120203021342.04B69B21B3@azwildcat.mtv.corp.google.com>
This code before the change seems to over-estimate the number of real
nodes which should be safe -- can you explain why it causes problem?
David
On Thu, Feb 2, 2012 at 6:13 PM, Sriraman Tallam <tmsriram@google.com> wrote:
> Fix a bug in the function reordering linker plugin where the number of nodes
> to be reordered is incremented in the wrong place. This caused a heap buffer
> to overflow under certain conditions.
>
> The linker plugin itself is only available in the google 4_6 branch and I will
> port it to other branches and make it available for review for trunk soon.
>
> ? ? ? ?* callgraph.c (parse_callgraph_section_contents): Remove increment
> ? ? ? ?to num_real_nodes.
> ? ? ? ?(set_node_type): Increment num_real_nodes.
>
> Index: function_reordering_plugin/callgraph.c
> ===================================================================
> --- function_reordering_plugin/callgraph.c ? ? ?(revision 183860)
> +++ function_reordering_plugin/callgraph.c ? ? ?(working copy)
> @@ -304,7 +304,6 @@ parse_callgraph_section_contents (unsigned char *s
> ? caller = caller + HEADER_LEN;
> ? curr_length = read_length;
> ? caller_node = get_function_node (caller);
> - ?num_real_nodes++;
>
> ? while (curr_length < length)
> ? ? {
> @@ -422,7 +421,10 @@ static void set_node_type (Node *n)
> ? char *name = n->name;
> ? slot = htab_find_with_hash (section_map, name, htab_hash_string (name));
> ? if (slot != NULL)
> - ? ?set_as_real_node (n);
> + ? ?{
> + ? ? ?set_as_real_node (n);
> + ? ? ?num_real_nodes++;
> + ? ?}
> ?}
>
> ?void
>
> --
> This patch is available for review at http://codereview.appspot.com/5623048