Commit Message
Hi.
This patch fixes symtab/17855.
Basically the issue is that breakpoint_re_set is currently being called
before observer_notify_new_objfile (NULL), and thus the ada symbol
cache (and the general symbol cache of a separate patch) aren't being
flushed first, so that when breakpoints are reset symbol lookup is being
done on a stale cache.
Regression tested on amd64-linux.
2015-01-19 Doug Evans <xdje42@gmail.com>
PR symtab/17855
* symfile.c (clear_symtab_users): Notify observers of change before
calling breakpoint_re_set.
Comments
On 01/20/2015 06:26 AM, Doug Evans wrote:
> Hi.
>
> This patch fixes symtab/17855.
> Basically the issue is that breakpoint_re_set is currently being called
> before observer_notify_new_objfile (NULL), and thus the ada symbol
> cache (and the general symbol cache of a separate patch) aren't being
> flushed first, so that when breakpoints are reset symbol lookup is being
> done on a stale cache.
>
> Regression tested on amd64-linux.
>
> 2015-01-19 Doug Evans <xdje42@gmail.com>
>
> PR symtab/17855
> * symfile.c (clear_symtab_users): Notify observers of change before
> calling breakpoint_re_set.
>
> diff --git a/gdb/symfile.c b/gdb/symfile.c
> index d55e361..ad481de 100644
> --- a/gdb/symfile.c
> +++ b/gdb/symfile.c
> @@ -3023,6 +3023,12 @@ clear_symtab_users (int add_flags)
> /* Someday, we should do better than this, by only blowing away
> the things that really need to be blown. */
>
> + /* Notify anyone listening that the previous loaded symtab(s) are invalid.
> + It is important to do this before calling breakpoint_re_set as the latter
> + will try to look up symbols, and for example the symbol cache needs to
> + be flushed first. */
> + observer_notify_new_objfile (NULL);
> +
> /* Clear the "current" symtab first, because it is no longer valid.
> breakpoint_re_set may try to access the current symtab. */
> clear_current_source_symtab_and_line ();
> @@ -3032,7 +3038,6 @@ clear_symtab_users (int add_flags)
> breakpoint_re_set ();
> clear_last_displayed_sal ();
> clear_pc_function_cache ();
> - observer_notify_new_objfile (NULL);
Looking at the whole function, ISTM that the breakpoint_re_set
call should move further down. I can imagine that breakpoint_re_set
could well hit a stale pc function cache, cleared only after by
clear_pc_function_cache. breakpoint.c:parse_breakpoint_sals also
references the last displayed sal. One would hope that breakpoint
re-set is independent of that, though the existing comment about
breakpoint_re_set accessing the current symtab leaves me
wondering. WDYT?
Thanks,
Pedro Alves
On Thu, Jan 22, 2015 at 3:41 AM, Pedro Alves <palves@redhat.com> wrote:
> Looking at the whole function, ISTM that the breakpoint_re_set
> call should move further down. I can imagine that breakpoint_re_set
> could well hit a stale pc function cache, cleared only after by
> clear_pc_function_cache. breakpoint.c:parse_breakpoint_sals also
> references the last displayed sal. One would hope that breakpoint
> re-set is independent of that, though the existing comment about
> breakpoint_re_set accessing the current symtab leaves me
> wondering. WDYT?
Fine by me.
@@ -3023,6 +3023,12 @@ clear_symtab_users (int add_flags)
/* Someday, we should do better than this, by only blowing away
the things that really need to be blown. */
+ /* Notify anyone listening that the previous loaded symtab(s) are invalid.
+ It is important to do this before calling breakpoint_re_set as the latter
+ will try to look up symbols, and for example the symbol cache needs to
+ be flushed first. */
+ observer_notify_new_objfile (NULL);
+
/* Clear the "current" symtab first, because it is no longer valid.
breakpoint_re_set may try to access the current symtab. */
clear_current_source_symtab_and_line ();
@@ -3032,7 +3038,6 @@ clear_symtab_users (int add_flags)
breakpoint_re_set ();
clear_last_displayed_sal ();
clear_pc_function_cache ();
- observer_notify_new_objfile (NULL);
/* Clear globals which might have pointed into a removed objfile.
FIXME: It's not clear which of these are supposed to persist