Mercurial > gnulib
view lib/malloca.c @ 40206:770a5696761e
relocatable-prog: Use wrapper-free installation on Mac OS X, take 2.
This approach supports relocatable installation of shared libraries
which depend on other shared libraries from the same package.
* m4/relocatable.m4 (gl_RELOCATABLE_BODY): Determine use_macos_tools.
If use_macos_tools is true, use reloc-ldflags and set LIBTOOL to be a
wrapper around the original LIBTOOL.
* build-aux/reloc-ldflags: Add support for Mac OS X, which uses the
token '@loader_path' instead of '$ORIGIN'.
* build-aux/libtool-reloc: New file.
* modules/relocatable-prog (Files): Add it.
* doc/relocatable-maint.texi (Supporting Relocation): Update to match
the recent changes. Document the need to set the *_LDFLAGS of libraries.
RELOCATABLE_LIBRARY_PATH and RELOCATABLE_CONFIG_H_DIR should be set in
Makefile.am, not in configure.ac.
author | Bruno Haible <bruno@clisp.org> |
---|---|
date | Mon, 04 Mar 2019 17:25:09 +0100 |
parents | b06060465f09 |
children |
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/* Safe automatic memory allocation. Copyright (C) 2003, 2006-2007, 2009-2019 Free Software Foundation, Inc. Written by Bruno Haible <bruno@clisp.org>, 2003, 2018. 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 2, 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 <https://www.gnu.org/licenses/>. */ #define _GL_USE_STDLIB_ALLOC 1 #include <config.h> /* Specification. */ #include "malloca.h" #include "verify.h" /* The speed critical point in this file is freea() applied to an alloca() result: it must be fast, to match the speed of alloca(). The speed of mmalloca() and freea() in the other case are not critical, because they are only invoked for big memory sizes. Here we use a bit in the address as an indicator, an idea by Ondřej Bílka. malloca() can return three types of pointers: - Pointers ≡ 0 mod 2*sa_alignment_max come from stack allocation. - Pointers ≡ sa_alignment_max mod 2*sa_alignment_max come from heap allocation. - NULL comes from a failed heap allocation. */ /* Type for holding very small pointer differences. */ typedef unsigned char small_t; /* Verify that it is wide enough. */ verify (2 * sa_alignment_max - 1 <= (small_t) -1); void * mmalloca (size_t n) { #if HAVE_ALLOCA /* Allocate one more word, used to determine the address to pass to freea(), and room for the alignment ≡ sa_alignment_max mod 2*sa_alignment_max. */ size_t nplus = n + sizeof (small_t) + 2 * sa_alignment_max - 1; if (nplus >= n) { char *mem = (char *) malloc (nplus); if (mem != NULL) { char *p = (char *)((((uintptr_t)mem + sizeof (small_t) + sa_alignment_max - 1) & ~(uintptr_t)(2 * sa_alignment_max - 1)) + sa_alignment_max); /* Here p >= mem + sizeof (small_t), and p <= mem + sizeof (small_t) + 2 * sa_alignment_max - 1 hence p + n <= mem + nplus. So, the memory range [p, p+n) lies in the allocated memory range [mem, mem + nplus). */ ((small_t *) p)[-1] = p - mem; /* p ≡ sa_alignment_max mod 2*sa_alignment_max. */ return p; } } /* Out of memory. */ return NULL; #else # if !MALLOC_0_IS_NONNULL if (n == 0) n = 1; # endif return malloc (n); #endif } #if HAVE_ALLOCA void freea (void *p) { /* Check argument. */ if ((uintptr_t) p & (sa_alignment_max - 1)) { /* p was not the result of a malloca() call. Invalid argument. */ abort (); } /* Determine whether p was a non-NULL pointer returned by mmalloca(). */ if ((uintptr_t) p & sa_alignment_max) { void *mem = (char *) p - ((small_t *) p)[-1]; free (mem); } } #endif /* * Hey Emacs! * Local Variables: * coding: utf-8 * End: */