Pedro Alves
bd9482bca7
With: - catch a fork in thread 1 - select thread 2 - set follow-fork child - next ... follow_fork notices that thread 1 had last stopped for a fork which hasn't been followed yet, and because thread 1 is not the current thread, GDB aborts the execution command, presenting the stop in thread 1. That makes sense, as only the forking thread (thread 1) survives in the child, so better stop and let the user decide how to proceed. However, with: - catch a fork in thread 1 - select thread 2 - set follow-fork parent << note difference here - next ... GDB does the same: follow_fork notices that thread 1 had last stopped for a fork which hasn't been followed yet, and because thread 1 is not the current thread, GDB aborts the execution command, presenting the stop in thread 1. Aborting/stopping in this case doesn't make sense to me. As we're following the parent, thread 2 will still continue to exist in the parent. What the child does after we've followed the parent shouldn't matter -- it can go on running free, be detached, etc., depending on "set schedule-multiple", "set detach-on-fork", etc. That does not influence the execution command that the user issued for the parent thread. So this patch changes GDB in that direction -- in follow_fork, if following the parent, and we've switched threads meanwhile, switch back to the unfollowed thread, follow it (stay with the parent), and don't abort/stop. If we're following a fork (as opposed to vfork), then switch back again to the thread that the user was trying to resume. If following a vfork, however, stay with the vforking-thread selected, as we will need to see a vfork_done event first, before we can resume any other thread. As I was working on this, I managed to end up calling target_resume for a solo-thread resume (to collect the vfork_done event), with scope_ptid pointing at the vfork parent thread, and inferior_ptid pointing to the vfork child. For a solo-thread resume, the scope_ptid argument to target_resume must the same as inferior_ptid. The mistake was caught by the assertion in target_resume, like so: ... [infrun] resume_1: step=0, signal=GDB_SIGNAL_0, trap_expected=0, current thread [1722839.1722839.0] at 0x5555555553c3 [infrun] do_target_resume: resume_ptid=1722839.1722939.0, step=0, sig=GDB_SIGNAL_0 ../../src/gdb/target.c:2661: internal-error: target_resume: Assertion `inferior_ptid.matches (scope_ptid)' failed. ... but I think it doesn't hurt to catch such a mistake earlier, hence the change in internal_resume_ptid. Change-Id: I896705506a16d2488b1bfb4736315dd966f4e412
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.