binutils-gdb modified for the FreeChainXenon project
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Simon Marchi a66f729819 gdb: maintain per-process-target list of resumed threads with pending wait status
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
2021-07-12 20:46:53 -04:00
bfd Automatic date update in version.in 2021-07-13 00:00:09 +00:00
binutils Updated French translation for the binutils sub-directory 2021-07-12 14:20:14 +01:00
config Add markers for 2.37 branch 2021-07-03 14:50:57 +01:00
contrib Import mklog.py from gcc repo 2020-09-25 10:24:44 -04:00
cpu Re: opcodes: constify & local meps macros 2021-07-05 21:40:49 +09:30
elfcpp Add markers for 2.37 branch 2021-07-03 14:50:57 +01:00
etc Update year range in copyright notice of binutils files 2021-01-01 10:31:05 +10:30
gas Add the SEC_ELF_OCTETS flag to debug sections created by the assembler. 2021-07-12 17:12:13 +01:00
gdb gdb: maintain per-process-target list of resumed threads with pending wait status 2021-07-12 20:46:53 -04:00
gdbserver gdbsupport/common.m4: check for sigtimedwait 2021-07-05 09:54:35 -04:00
gdbsupport gdb: maintain per-process-target list of resumed threads with pending wait status 2021-07-12 20:46:53 -04:00
gnulib gnulib: define the path to gnulib's parent dir 2021-06-14 18:01:20 -04:00
gold Updated translations (mainly Ukranian and French) triggered by creation of 2.37 branch. 2021-07-05 15:54:35 +01:00
gprof Updated translations (mainly Ukranian and French) triggered by creation of 2.37 branch. 2021-07-05 15:54:35 +01:00
include elf: Add GNU_PROPERTY_1_NEEDED check 2021-07-08 18:14:31 -07:00
intl GNU gettext introduced this change[0] in version 0.19.8 to fix gettext detection with musl libc, since it does not define these internal symbols. 2021-06-14 14:05:39 +01:00
ld ld/NEWS: Clarify -z [no]indirect-extern-access 2021-07-09 07:36:42 -07:00
libctf Add markers for 2.37 branch 2021-07-03 14:50:57 +01:00
libdecnumber Run autoreconf -vf throughout 2020-07-29 16:03:55 -04:00
libiberty Restore the libiberty component of commit 50ad1254d5. 2021-07-05 16:21:42 +01:00
opcodes Add changelog entries for last commit 2021-07-07 14:17:05 +02:00
readline Update config.sub and config.guess for MIPS R3 and R5 ISA support 2021-05-24 18:11:49 +02:00
sim sim: erc32: use libsim.a for common objects 2021-07-08 02:30:37 -04:00
texinfo
zlib GCC: Check if AR works with --plugin and rc 2021-01-11 16:26:51 -08:00
.cvsignore
.gitattributes
.gitignore Add gnu global outputs to .gitignore 2020-12-02 10:00:27 -05:00
ar-lib
ChangeLog Add markers for 2.37 branch 2021-07-03 14:50:57 +01:00
compile
config-ml.in
config.guess Update config.sub and config.guess for MIPS R3 and R5 ISA support 2021-05-24 18:11:49 +02:00
config.rpath
config.sub Update config.sub and config.guess for MIPS R3 and R5 ISA support 2021-05-24 18:11:49 +02:00
configure sim: leverage gnulib 2021-05-29 11:56:43 -04:00
configure.ac sim: leverage gnulib 2021-05-29 11:56:43 -04:00
COPYING
COPYING.LIB
COPYING.LIBGLOSS
COPYING.NEWLIB
COPYING3
COPYING3.LIB
depcomp
djunpack.bat
install-sh
libtool.m4 GCC: Check if AR works with --plugin and rc 2021-01-11 16:26:51 -08:00
ltgcc.m4
ltmain.sh
ltoptions.m4
ltsugar.m4
ltversion.m4
lt~obsolete.m4
MAINTAINERS MAINTAINERS: Update path to readline config.{sub,guess} files 2021-05-24 18:11:49 +02:00
Makefile.def sim: depend on gnulib 2021-05-18 17:47:27 -04:00
Makefile.in sim: depend on gnulib 2021-05-18 17:47:27 -04:00
Makefile.tpl Add missing changes to Makefile.tpl 2021-02-28 04:39:38 -08:00
makefile.vms
missing
mkdep
mkinstalldirs
move-if-change
multilib.am Merge autoconf / automake update changes from GCC. 2018-10-31 17:10:56 +00:00
README
README-maintainer-mode
setup.com
src-release.sh src-release: fix indentation 2021-01-12 18:19:20 -05:00
symlink-tree
test-driver
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.