Go to file
Pedro Alves 49fa26b041 PR gdb/11568 - delete thread-specific breakpoints on thread exit
PR gdb/11568 is about thread-specific breakpoints being left behind
when the corresponding thread exits.

Currently:

 (gdb) b start thread 2
 Breakpoint 3 at 0x400614: file thread-specific-bp.c, line 23.
 (gdb) b end
 Breakpoint 4 at 0x40061f: file thread-specific-bp.c, line 29.
 (gdb) c
 Continuing.
 [Thread 0x7ffff7fcb700 (LWP 14925) exited]
 [Switching to Thread 0x7ffff7fcc740 (LWP 14921)]

 Breakpoint 4, end () at thread-specific-bp.c:29
 29      }
 (gdb) info threads
   Id   Target Id         Frame
 * 1    Thread 0x7ffff7fcc740 (LWP 14921) "thread-specific" end () at thread-specific-bp.c:29
 (gdb) info breakpoints
 Num     Type           Disp Enb Address            What
 2       breakpoint     keep y   0x0000000000400614 in start at thread-specific-bp.c:23
         breakpoint already hit 1 time
 3       breakpoint     keep y   0x0000000000400614 in start at thread-specific-bp.c:23 thread 2
         stop only in thread 2
 4       breakpoint     keep y   0x000000000040061f in end at thread-specific-bp.c:29
         breakpoint already hit 1 time

Note that the thread-specific breakpoint 3 stayed around, even though
thread 2 is gone.

There's no way that breakpoint can trigger again (*), so the PR argues
that the breakpoint should just be removed, like local watchpoints.
I'm ambivalent on this -- it could be reasonable to disable the
breakpoint (kind of like breakpoint in shared library code when the
DSO is unloaded), so the user could still use it as visual template
for creating other breakpoints (copy/paste command lists, etc.), or we
could have a way to change to which thread a breakpoint applies.  But,
several people pushed this direction, and I don't plan on arguing...

(*) - actually, there is ...  thread numbers are reset on "run", so
the user could do "break foo thread 2", "run", and expect the
breakpoint to hit again on the second thread.  But given gdb's thread
numbering can't really be stable, that'd only work sufficiently well
for thread 1, so we'd better call it unsupported.

So with the patch, whenever a thread is deleted from GDB's list, GDB
goes through the thread-specific breakpoints and deletes corresponding
breakpoints.  Since this is user-visible, GDB prints out:

  Thread-specific breakpoint 3 deleted - thread 2 is gone.

And of course, we end up with:

 (gdb) info breakpoints
 Num     Type           Disp Enb Address            What
 2       breakpoint     keep y   0x0000000000400614 in start at thread-specific-bp.c:23
         breakpoint already hit 1 time
 4       breakpoint     keep y   0x000000000040061f in end at thread-specific-bp.c:29
         breakpoint already hit 1 time

2013-09-17  Muhammad Waqas <mwaqas@codesourcery.com>
	    Pedro Alves  <palves@redhat.com>

	PR gdb/11568
	* breakpoint.c (remove_threaded_breakpoints): New function.
	(_initialize_breakpoint): Attach remove_threaded_breakpoints
	as thread_exit observer.

2013-09-17  Muhammad Waqas  <mwaqas@codesourccery.com>
	    Jan Kratochvil  <jan.kartochvil@redhat.com>
	    Pedro Alves  <palves@redhat.com>

	PR gdb/11568
	* gdb.thread/thread-specific-bp.c: New file.
	* gdb.thread/thread-specific-bp.exp: New file.
2013-09-17 19:32:47 +00:00
bfd daily update 2013-09-17 00:00:04 +00:00
binutils * dwarf.c (dwarf_vmatoa): Rename to dwarf_vmatoa_1 and add a 2013-09-12 09:14:47 +00:00
config
cpu
elfcpp
etc
gas opcodes/ 2013-09-17 09:02:37 +00:00
gdb PR gdb/11568 - delete thread-specific breakpoints on thread exit 2013-09-17 19:32:47 +00:00
gold
gprof
include
intl
ld PR ld/15957 2013-09-17 13:57:21 +00:00
libdecnumber
libiberty merge from gcc 2013-09-12 16:08:09 +00:00
opcodes opcodes/ 2013-09-17 09:02:37 +00:00
readline
sim
texinfo
.cvsignore
.gitignore
ChangeLog
compile
config-ml.in
config.guess
config.rpath
config.sub
configure
configure.ac
COPYING
COPYING3
COPYING3.LIB
COPYING.LIB
COPYING.LIBGLOSS
COPYING.NEWLIB
depcomp
djunpack.bat
install-sh
libtool.m4
lt~obsolete.m4
ltgcc.m4
ltmain.sh
ltoptions.m4
ltsugar.m4
ltversion.m4
MAINTAINERS
Makefile.def
Makefile.in
Makefile.tpl
makefile.vms
missing
mkdep
mkinstalldirs
move-if-change
README
README-maintainer-mode
setup.com
src-release
symlink-tree
ylwrap

		   README for GNU development tools

This directory contains various GNU compilers, assemblers, linkers, 
debuggers, etc., plus their support routines, definitions, and documentation.

If you are receiving this as part of a GDB release, see the file gdb/README.
If with a binutils release, see binutils/README;  if with a libg++ release,
see libg++/README, etc.  That'll give you info about this
package -- supported targets, how to use it, how to report bugs, etc.

It is now possible to automatically configure and build a variety of
tools with one command.  To build all of the tools contained herein,
run the ``configure'' script here, e.g.:

	./configure 
	make

To install them (by default in /usr/local/bin, /usr/local/lib, etc),
then do:
	make install

(If the configure script can't determine your type of computer, give it
the name as an argument, for instance ``./configure sun4''.  You can
use the script ``config.sub'' to test whether a name is recognized; if
it is, config.sub translates it to a triplet specifying CPU, vendor,
and OS.)

If you have more than one compiler on your system, it is often best to
explicitly set CC in the environment before running configure, and to
also set CC when running make.  For example (assuming sh/bash/ksh):

	CC=gcc ./configure
	make

A similar example using csh:

	setenv CC gcc
	./configure
	make

Much of the code and documentation enclosed is copyright by
the Free Software Foundation, Inc.  See the file COPYING or
COPYING.LIB in the various directories, for a description of the
GNU General Public License terms under which you can copy the files.

REPORTING BUGS: Again, see gdb/README, binutils/README, etc., for info
on where and how to report problems.