mirror of
https://sourceware.org/git/binutils-gdb.git
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63a4b10683
This copies in libbacktrace from the gcc repository as it was in the commit 62e420293a293608f383d9b9c7f2debd666e9fc9. GDB is going to start using this library soon. A dependency between GDB and libbacktrace has already been added to the top level Makefile, so, after this commit, when building GDB, libbacktrace will be built first. However, libbacktrace is not yet linked into GDB, or used by GDB in any way. It is possible to stop libbacktrace being built by configuring the tree with --disable-libbacktrace. This commit does NOT update src-release.sh, that will be done in the next commit, this commit ONLY imports libbacktrace from gcc. This means that if you try to make a release of GDB from exactly this commit then the release tar file will not include libbacktrace. However, as libbacktrace is an optional dependency this is fine.
109 lines
3.1 KiB
C
109 lines
3.1 KiB
C
/* sort.c -- Sort without allocating memory
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Copyright (C) 2012-2021 Free Software Foundation, Inc.
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Written by Ian Lance Taylor, Google.
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions are
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met:
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(1) Redistributions of source code must retain the above copyright
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notice, this list of conditions and the following disclaimer.
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(2) Redistributions in binary form must reproduce the above copyright
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notice, this list of conditions and the following disclaimer in
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the documentation and/or other materials provided with the
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distribution.
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(3) The name of the author may not be used to
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endorse or promote products derived from this software without
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specific prior written permission.
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THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
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INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
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STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
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IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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POSSIBILITY OF SUCH DAMAGE. */
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#include "config.h"
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#include <stddef.h>
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#include <sys/types.h>
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#include "backtrace.h"
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#include "internal.h"
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/* The GNU glibc version of qsort allocates memory, which we must not
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do if we are invoked by a signal handler. So provide our own
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sort. */
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static void
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swap (char *a, char *b, size_t size)
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{
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size_t i;
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for (i = 0; i < size; i++, a++, b++)
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{
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char t;
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t = *a;
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*a = *b;
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*b = t;
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}
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}
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void
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backtrace_qsort (void *basearg, size_t count, size_t size,
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int (*compar) (const void *, const void *))
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{
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char *base = (char *) basearg;
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size_t i;
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size_t mid;
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tail_recurse:
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if (count < 2)
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return;
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/* The symbol table and DWARF tables, which is all we use this
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routine for, tend to be roughly sorted. Pick the middle element
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in the array as our pivot point, so that we are more likely to
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cut the array in half for each recursion step. */
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swap (base, base + (count / 2) * size, size);
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mid = 0;
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for (i = 1; i < count; i++)
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{
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if ((*compar) (base, base + i * size) > 0)
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{
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++mid;
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if (i != mid)
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swap (base + mid * size, base + i * size, size);
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}
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}
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if (mid > 0)
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swap (base, base + mid * size, size);
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/* Recurse with the smaller array, loop with the larger one. That
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ensures that our maximum stack depth is log count. */
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if (2 * mid < count)
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{
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backtrace_qsort (base, mid, size, compar);
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base += (mid + 1) * size;
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count -= mid + 1;
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goto tail_recurse;
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}
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else
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{
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backtrace_qsort (base + (mid + 1) * size, count - (mid + 1),
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size, compar);
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count = mid;
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goto tail_recurse;
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}
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}
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