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[binutils-gdb] Don't call clear_quit_flag in prepare_to_throw_exception
- From: Pedro Alves <palves at sourceware dot org>
- To: gdb-cvs at sourceware dot org
- Date: 12 Apr 2016 16:10:55 -0000
- Subject: [binutils-gdb] Don't call clear_quit_flag in prepare_to_throw_exception
https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=0af679c6e0645a93d5a60ec936b94dc70a2f9e5c
commit 0af679c6e0645a93d5a60ec936b94dc70a2f9e5c
Author: Pedro Alves <palves@redhat.com>
Date: Tue Apr 12 16:49:30 2016 +0100
Don't call clear_quit_flag in prepare_to_throw_exception
I think this is reminiscent of the time when a longjmp would always
jump to the top level. Nowaways code that throw exceptions other than
a quit, which may even be caught and handled without reaching the top
level. Certainly such exceptions shouldn't clear an interrupt
request...
(We also need to get rid of prepare_to_throw_exception in order to be
able to just do "throw ex;" in C++.)
One could argue that we should clear the quit flag when we throw a
quit from the SIGINT handler, when immediate_quit is in effect, to
handle a race, here:
immediate_quit++;
QUIT;
... that's the usual pattern code must use when enabling
immediate_quit. The QUIT is there to catch the case of Ctrl-C having
already been pressed before immediate_quit was enabled. However, this
can happen:
immediate_quit++;
<< Ctrl-C pressed here too.
QUIT;
And in that case, if the quit flag was already set, it'll stay set
even after throwing a quit from the SIGINT handler. The end result is
a double quit. But OTOH, the user did press Ctrl-C two times. Since
I'm getting rid of immediate_quit, I'm not bothering with this.
gdb/ChangeLog:
2016-04-12 Pedro Alves <palves@redhat.com>
* exceptions.c (prepare_to_throw_exception): Don't clear the quit
flag.
Diff:
---
gdb/ChangeLog | 5 +++++
gdb/exceptions.c | 1 -
2 files changed, 5 insertions(+), 1 deletion(-)
diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index f01183e..6b4518c 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,5 +1,10 @@
2016-04-12 Pedro Alves <palves@redhat.com>
+ * exceptions.c (prepare_to_throw_exception): Don't clear the quit
+ flag.
+
+2016-04-12 Pedro Alves <palves@redhat.com>
+
* event-top.c (command_handler): Don't call clear_quit_flag.
2016-04-12 Pedro Alves <palves@redhat.com>
diff --git a/gdb/exceptions.c b/gdb/exceptions.c
index 8ba86fc..b457838 100644
--- a/gdb/exceptions.c
+++ b/gdb/exceptions.c
@@ -30,7 +30,6 @@
void
prepare_to_throw_exception (void)
{
- clear_quit_flag ();
immediate_quit = 0;
}