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Re: [rfc] Print solib events in mi-mode
- From: Jason Molenda <jmolenda at apple dot com>
- To: Kris Warkentin <kewarken at qnx dot com>
- Cc: "Gdb at Sources dot Redhat dot Com" <gdb at sources dot redhat dot com>
- Date: Wed, 9 Jul 2003 13:38:44 -0700
- Subject: Re: [rfc] Print solib events in mi-mode
- References: <062401c34590$97cd09b0$0202040a@catdog>
Hi Kris,
On Tuesday, July 8, 2003, at 1:36 PM, Kris Warkentin wrote:
What do you think of something like this? When stop-on-solib-events
is set,
this will print the reason as being a shared-lib-event.
For what it's worth, at Apple we do something very similar. This
section of code in breakpoint.c reads:
case bp_shlib_event:
/* Did we stop because the user set the stop_on_solib_events
variable? (If so, we report this as a generic, "Stopped due
to shlib event" message.) */
if (interpreter_p && strncmp (interpreter_p, "mi", 2) == 0)
ui_out_field_string (uiout, "reason", "shlib-event");
else
printf_filtered ("Stopped due to shared library event\n");
return PRINT_NOTHING;
break;
For the case where stop-on-shlibs-added is not set, we have an MI
notification that gets posted each time a shared library is loaded. It
looks like this to the UI side:
=shlibs-updated
=shlibs-added,shlib-info=[num="54",name="SKTDrawDocument.ob",kind="-
",dyld-addr="0x271000",reason="dyld",requested-
state="?",state="N",path="/Developer/Examples/AppKit/Sketch/build/
Sketch.build/Sketch
(Upgraded).build/Objects-normal/ppc/
SKTDrawDocument.ob",slide="",addr="",prefix=""]
~"Re-enabling shared library breakpoints: 1\n"
<-
=shlibs-added,shlib-info=[num="55",name="SKTGraphic.ob",kind="-",dyld-
addr="0x28a000",reason="dyld",requested-state="?",state="N",path="/
Developer/Examples/AppKit/Sketch/build/Sketch.build/Sketch
(Upgraded).build/Objects-normal/ppc/
SKTGraphic.ob",slide="",addr="",prefix=""]
In our case, this message is emitted by one of our arch-specific files,
macosx/macosx-nat-dyld.c, in a function called macosx_solib_add().
Our Eclipse team wants to be able to set breakpoints in shared
libraries
that aren't loaded yet. If they get notification of shlib-events,
then they
can re-examine the list of loaded libraries and set any breakpoints
that
have been enabled in the project's libs.
We handled this problem by creating a new breakpoint command,
"future-break" (short: "fb", done in MI as "-break-insert -f ...").
This pushes the logic down in to gdb. On the one hand, it's expensive
to have gdb trying to set this breakpoint for every shared library that
comes in (when you have a lot of big shared libraries like we do on
MacOS X), but at the same time if the IDE is responsible for setting
breakpoints in shared libraries then you'll have to stop on each solib
add event to set those breakpoints before anything runs...
You can see all of this in the above sample; breakpoint #1 was a
file:line breakpoint, which was in SKTGraphic.ob. When SKTGraphic.ob
was paged in (this is a project using ZeroLink, so each source file is
a separate objfile, pulled in at run-time as needed), the breakpoint
was set by gdb.
The future-break patches were posted at least once in the past along
with the save-breakpoints command; I can find a URL ref if anyone
cares.
Jason
cheers,
Kris
$ cvs diff -u breakpoint.c
Index: breakpoint.c
===================================================================
RCS file: /cvs/src/src/gdb/breakpoint.c,v
retrieving revision 1.125
diff -u -r1.125 breakpoint.c
--- breakpoint.c 2 Jul 2003 16:24:00 -0000 1.125
+++ breakpoint.c 8 Jul 2003 20:32:50 -0000
@@ -2039,8 +2039,10 @@
/* Did we stop because the user set the stop_on_solib_events
variable? (If so, we report this as a generic, "Stopped due
to shlib event" message.) */
- printf_filtered ("Stopped due to shared library event\n");
- return PRINT_NOTHING;
+ ui_out_text (uiout, "\nShared library event ");
+ if (ui_out_is_mi_like_p (uiout))
+ ui_out_field_string (uiout, "reason", "shared-lib-event");
+ return PRINT_SRC_ONLY;
break;
case bp_thread_event: