binutils-gdb/gdbsupport/parallel-for.h
Tom Tromey 01027315f5 Move gdbsupport to the top level
This patch moves the gdbsupport directory to the top level.  This is
the next step in the ongoing project to move gdbserver to the top
level.

The bulk of this patch was created by "git mv gdb/gdbsupport gdbsupport".

This patch then adds a build system to gdbsupport and wires it into
the top level.  Then it changes gdb to use the top-level build.

gdbserver, on the other hand, is not yet changed.  It still does its
own build of gdbsupport.

ChangeLog
2020-01-14  Tom Tromey  <tom@tromey.com>

	* src-release.sh (GDB_SUPPORT_DIRS): Add gdbsupport.
	* MAINTAINERS: Add gdbsupport.
	* configure: Rebuild.
	* configure.ac (configdirs): Add gdbsupport.
	* gdbsupport: New directory, move from gdb/gdbsupport.
	* Makefile.def (host_modules, dependencies): Add gnulib.
	* Makefile.in: Rebuild.

gdb/ChangeLog
2020-01-14  Tom Tromey  <tom@tromey.com>

	* nat/x86-linux-dregs.c: Include configh.h.
	* nat/linux-ptrace.c: Include configh.h.
	* nat/linux-btrace.c: Include configh.h.
	* defs.h: Include config.h, bfd.h.
	* configure.ac: Don't source common.host.
	(CONFIG_OBS, CONFIG_SRCS): Remove gdbsupport files.
	* configure: Rebuild.
	* acinclude.m4: Update path.
	* Makefile.in (SUPPORT, LIBSUPPORT, INCSUPPORT): New variables.
	(CONFIG_SRC_SUBDIR): Remove gdbsupport.
	(INTERNAL_CFLAGS_BASE): Add INCSUPPORT.
	(CLIBS): Add LIBSUPPORT.
	(CDEPS): Likewise.
	(COMMON_SFILES): Remove gdbsupport files.
	(HFILES_NO_SRCDIR): Likewise.
	(stamp-version): Update path to create-version.sh.
	(ALLDEPFILES): Remove gdbsupport files.

gdb/gdbserver/ChangeLog
2020-01-14  Tom Tromey  <tom@tromey.com>

	* server.h: Include config.h.
	* gdbreplay.c: Include config.h.
	* configure: Rebuild.
	* configure.ac: Don't source common.host.
	* acinclude.m4: Update path.
	* Makefile.in (INCSUPPORT): New variable.
	(INCLUDE_CFLAGS): Add INCSUPPORT.
	(SFILES): Update paths.
	(version-generated.c): Update path to create-version.sh.
	(gdbsupport/%-ipa.o, gdbsupport/%.o): Update paths.

gdbsupport/ChangeLog
2020-01-14  Tom Tromey  <tom@tromey.com>

	* common-defs.h: Add GDBSERVER case.  Update includes.
	* acinclude.m4, aclocal.m4, config.in, configure, configure.ac,
	Makefile.am, Makefile.in, README: New files.
	* Moved from ../gdb/gdbsupport/

Change-Id: I07632e7798635c1bab389bf885971e584fb4bb78
2020-01-14 16:25:02 -07:00

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2.5 KiB
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/* Parallel for loops
Copyright (C) 2019-2020 Free Software Foundation, Inc.
This file is part of GDB.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>. */
#ifndef GDBSUPPORT_PARALLEL_FOR_H
#define GDBSUPPORT_PARALLEL_FOR_H
#include <algorithm>
#if CXX_STD_THREAD
#include <thread>
#include "gdbsupport/thread-pool.h"
#endif
namespace gdb
{
/* A very simple "parallel for". This splits the range of iterators
into subranges, and then passes each subrange to the callback. The
work may or may not be done in separate threads.
This approach was chosen over having the callback work on single
items because it makes it simple for the caller to do
once-per-subrange initialization and destruction. */
template<class RandomIt, class RangeFunction>
void
parallel_for_each (RandomIt first, RandomIt last, RangeFunction callback)
{
#if CXX_STD_THREAD
/* So we can use a local array below. */
const size_t local_max = 16;
size_t n_threads = std::min (thread_pool::g_thread_pool->thread_count (),
local_max);
size_t n_actual_threads = 0;
std::future<void> futures[local_max];
size_t n_elements = last - first;
if (n_threads > 1)
{
/* Arbitrarily require that there should be at least 10 elements
in a thread. */
if (n_elements / n_threads < 10)
n_threads = std::max (n_elements / 10, (size_t) 1);
size_t elts_per_thread = n_elements / n_threads;
n_actual_threads = n_threads - 1;
for (int i = 0; i < n_actual_threads; ++i)
{
RandomIt end = first + elts_per_thread;
auto task = [=] ()
{
callback (first, end);
};
futures[i] = gdb::thread_pool::g_thread_pool->post_task (task);
first = end;
}
}
#endif /* CXX_STD_THREAD */
/* Process all the remaining elements in the main thread. */
callback (first, last);
#if CXX_STD_THREAD
for (int i = 0; i < n_actual_threads; ++i)
futures[i].wait ();
#endif /* CXX_STD_THREAD */
}
}
#endif /* GDBSUPPORT_PARALLEL_FOR_H */