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Looking up threads that are both resumed and have a pending wait status to report is something that we do quite often in the fast path and is expensive if there are many threads, since it currently requires walking whole thread lists. The first instance is in maybe_set_commit_resumed_all_targets. This is called after handling each event in fetch_inferior_event, to see if we should ask targets to commit their resumed threads or not. If at least one thread is resumed but has a pending wait status, we don't ask the targets to commit their resumed threads, because we want to consume and handle the pending wait status first. The second instance is in random_pending_event_thread, where we want to select a random thread among all those that are resumed and have a pending wait status. This is called every time we try to consume events, to see if there are any pending events that we we want to consume, before asking the targets for more events. To allow optimizing these cases, maintain a per-process-target list of threads that are resumed and have a pending wait status. In maybe_set_commit_resumed_all_targets, we'll be able to check in O(1) if there are any such threads simply by checking whether the list is empty. In random_pending_event_thread, we'll be able to use that list, which will be quicker than iterating the list of threads, especially when there are no resumed with pending wait status threads. About implementation details: using the new setters on class thread_info, it's relatively easy to maintain that list. Any time the "resumed" or "pending wait status" property is changed, we check whether that should cause the thread to be added or removed from the list. In set_thread_exited, we try to remove the thread from the list, because keeping an exited thread in that list would make no sense (especially if the thread is freed). My first implementation assumed that a process stratum target was always present when set_thread_exited is called. That's however, not the case: in some cases, targets unpush themselves from an inferior and then call "exit_inferior", which exits all the threads. If the target is unpushed before set_thread_exited is called on the threads, it means we could mistakenly leave some threads in the list. I tried to see how hard it would be to make it such that targets have to exit all threads before unpushing themselves from the inferior (that would seem logical to me, we don't want threads belonging to an inferior that has no process target). That seemed quite difficult and not worth the time at the moment. Instead, I changed inferior::unpush_target to remove all threads of that inferior from the list. As of this patch, the list is not used, this is done in the subsequent patches. The debug messages in process-stratum-target.c need to print some ptids. However, they can't use target_pid_to_str to print them without introducing a dependency on the current inferior (the current inferior is used to get the current target stack). For debug messages, I find it clearer to print the spelled out ptid anyway (the pid, lwp and tid values). Add a ptid_t::to_string method that returns a string representation of the ptid that is meant for debug messages, a bit like we already have frame_id::to_string. Change-Id: Iad8f93db2d13984dd5aa5867db940ed1169dbb67
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.