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Re: [PATCH][PR symtab/17855] Fix.
- From: Joel Brobecker <brobecker at adacore dot com>
- To: Doug Evans <xdje42 at gmail dot com>
- Cc: Pedro Alves <palves at redhat dot com>, gdb-patches at sourceware dot org
- Date: Thu, 29 Jan 2015 11:19:29 +0400
- Subject: Re: [PATCH][PR symtab/17855] Fix.
- Authentication-results: sourceware.org; auth=none
- References: <m33876ary6 dot fsf at sspiff dot org> <54C0E1FF dot 4050201 at redhat dot com> <m3egqe83x3 dot fsf at sspiff dot org>
Aargh - I was working on it just now because I wasn't sure if anyone
felt they "had the ball on their court".
> Like so?
>
> 2015-01-28 Doug Evans <xdje42@gmail.com>
>
> PR symtab/17855
> * symfile.c (clear_symtab_users): Move call to breakpoint_re_set
> closer to end.
What I've tested is moving the call last, as shown in the attached
diff. Not technically necessarily better, but as the comment explains,
I move it last so that it's after we've purged all relevant caches.
That way, the function is organized in two rough sections:
- do purges first;
- do updates next.
Your comment is a lot more detailed, I like it.
> diff --git a/gdb/symfile.c b/gdb/symfile.c
> index d55e361..bad244c 100644
> --- a/gdb/symfile.c
> +++ b/gdb/symfile.c
> @@ -3023,13 +3023,8 @@ 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. */
>
> - /* Clear the "current" symtab first, because it is no longer valid.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 ();
> -
> clear_displays ();
> - if ((add_flags & SYMFILE_DEFER_BP_RESET) == 0)
> - breakpoint_re_set ();
> clear_last_displayed_sal ();
> clear_pc_function_cache ();
> observer_notify_new_objfile (NULL);
> @@ -3040,9 +3035,19 @@ clear_symtab_users (int add_flags)
> expression_context_block = NULL;
> innermost_block = NULL;
>
> + /* Now that most everything has been reset, reset any existing breakpoints.
> + Reasons for doing this after the above are that breakpoint resetting may
> + involve:
> + - reading the current source symtab and line,
> + - reading the last displayed sal,
> + - reading the pc function cache,
> + - symbol lookup which requires, for example, invalidating any caches
> + first. */
> + if ((add_flags & SYMFILE_DEFER_BP_RESET) == 0)
> + breakpoint_re_set ();
> +
> /* Varobj may refer to old symbols, perform a cleanup. */
> varobj_invalidate ();
> -
> }
>
> static void
>
>
>
--
Joel
diff --git a/gdb/symfile.c b/gdb/symfile.c
index d55e361..04a5c58 100644
--- a/gdb/symfile.c
+++ b/gdb/symfile.c
@@ -3028,8 +3028,6 @@ clear_symtab_users (int add_flags)
clear_current_source_symtab_and_line ();
clear_displays ();
- if ((add_flags & SYMFILE_DEFER_BP_RESET) == 0)
- breakpoint_re_set ();
clear_last_displayed_sal ();
clear_pc_function_cache ();
observer_notify_new_objfile (NULL);
@@ -3043,6 +3041,10 @@ clear_symtab_users (int add_flags)
/* Varobj may refer to old symbols, perform a cleanup. */
varobj_invalidate ();
+ /* Now that the various caches have been cleared, we can re_set
+ our breakpoints without risking it using stale data. */
+ if ((add_flags & SYMFILE_DEFER_BP_RESET) == 0)
+ breakpoint_re_set ();
}
static void