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[PATCH] Don't attach to 'target_changed' observer in regcache
- From: Yao Qi <yao at codesourcery dot com>
- To: <gdb-patches at sourceware dot org>
- Date: Thu, 2 Aug 2012 15:17:27 +0800
- Subject: [PATCH] Don't attach to 'target_changed' observer in regcache
Hi,
When I am modifying 'target_changed' observer, I don't understand
why we attach regcache_observer_target_changed to 'target_changed'
observer, and invalidates all regcache. 'target_changed' observer
is notified in valops.c:value_assign, before that, register is
modified by calling either gdbarch_value_to_register or
put_frame_register_bytes. Looks like regcache is in a good state,
why do we have to invalidate them?
The code that invalidates all regcache was added by this patch,
Multiplexed registers and invalidating the register cache
http://sourceware.org/ml/gdb-patches/2004-04/msg00282.html
The author (Orjan) tried to support "changing the bank select register
changes the contents (and meaning) for a whole set of other registers."
The requirement is quite specific to Orjan's own port, so the better
solution is to attach a function which invalidates all regcache in
Orjan's backend, instead of doing it in target-independent part.
With this patch, I can see that the number of regcache allocation/release
is reduced (16 -> 15) in test case (mi-cli.exp). For a large
multi-threaded app, we'll get better gain.
Regression tested on x86_64-linux native and gdbserver. OK for HEAD?
gdb:
2012-08-02 Yao Qi <yao@codesourcery.com>
* regcache.c (regcache_observer_target_changed): Remove.
(_initialize_regcache): Don't call observer_attach_target_changed.
---
gdb/regcache.c | 10 ----------
1 files changed, 0 insertions(+), 10 deletions(-)
diff --git a/gdb/regcache.c b/gdb/regcache.c
index c716280..3f83cfa 100644
--- a/gdb/regcache.c
+++ b/gdb/regcache.c
@@ -512,15 +512,6 @@ get_current_regcache (void)
return get_thread_regcache (inferior_ptid);
}
-
-/* Observer for the target_changed event. */
-
-static void
-regcache_observer_target_changed (struct target_ops *target)
-{
- registers_changed ();
-}
-
/* Update global variables old ptids to hold NEW_PTID if they were
holding OLD_PTID. */
static void
@@ -1405,7 +1396,6 @@ _initialize_regcache (void)
regcache_descr_handle
= gdbarch_data_register_post_init (init_regcache_descr);
- observer_attach_target_changed (regcache_observer_target_changed);
observer_attach_thread_ptid_changed (regcache_thread_ptid_changed);
add_com ("flushregs", class_maintenance, reg_flush_command,
--
1.7.7.6