85 lines
3.4 KiB
Text
85 lines
3.4 KiB
Text
# realloc.m4
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# serial 39
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dnl Copyright (C) 2007, 2009-2024 Free Software Foundation, Inc.
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dnl This file is free software; the Free Software Foundation
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dnl gives unlimited permission to copy and/or distribute it,
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dnl with or without modifications, as long as this notice is preserved.
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dnl This file is offered as-is, without any warranty.
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# An an experimental option, the user can request a sanitized realloc()
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# implementation, i.e. one that aborts upon undefined behaviour,
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# by setting
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# gl_cv_func_realloc_sanitize=yes
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# at configure time.
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AC_DEFUN([gl_FUNC_REALLOC_SANITIZED],
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[
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AC_CACHE_CHECK([whether realloc should abort upon undefined behaviour],
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[gl_cv_func_realloc_sanitize],
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[test -n "$gl_cv_func_realloc_sanitize" || gl_cv_func_realloc_sanitize=no])
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])
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# gl_FUNC_REALLOC_POSIX
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# ---------------------
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# Test whether 'realloc' is POSIX compliant (sets errno to ENOMEM when it
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# fails, and doesn't mess up with ptrdiff_t overflow),
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# and replace realloc if it is not.
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AC_DEFUN([gl_FUNC_REALLOC_POSIX],
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[
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AC_REQUIRE([gl_STDLIB_H_DEFAULTS])
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AC_REQUIRE([gl_FUNC_MALLOC_POSIX])
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AC_REQUIRE([gl_FUNC_REALLOC_SANITIZED])
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if test "$gl_cv_func_realloc_sanitize" != no; then
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REPLACE_REALLOC_FOR_REALLOC_POSIX=1
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AC_DEFINE([NEED_SANITIZED_REALLOC], [1],
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[Define to 1 if realloc should abort upon undefined behaviour.])
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else
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REPLACE_REALLOC_FOR_REALLOC_POSIX=$REPLACE_MALLOC_FOR_MALLOC_POSIX
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fi
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])
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# gl_FUNC_REALLOC_0_NONNULL
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# -------------------------
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# Replace realloc if realloc (..., 0) returns null.
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# Modules that use this macro directly or indirectly should depend
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# on extensions-aix, so that _LINUX_SOURCE_COMPAT gets defined
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# before this macro gets invoked. This helps if !(__VEC__ || __AIXVEC),
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# and doesn't hurt otherwise.
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AC_DEFUN([gl_FUNC_REALLOC_0_NONNULL],
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[
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AC_REQUIRE([gl_STDLIB_H_DEFAULTS])
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AC_REQUIRE([AC_CANONICAL_HOST])dnl for cross-compiles
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AC_REQUIRE([gl_FUNC_REALLOC_POSIX])
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AC_CACHE_CHECK([whether realloc (..., 0) returns nonnull],
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[gl_cv_func_realloc_0_nonnull],
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[AC_RUN_IFELSE(
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[AC_LANG_PROGRAM(
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[[#include <stdlib.h>
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/* Use prealloc to test; "volatile" prevents the compiler
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from optimizing the realloc call away. */
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void *(*volatile prealloc) (void *, size_t) = realloc;]],
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[[void *p = prealloc (0, 0);
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int result = !p;
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p = prealloc (p, 0);
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result |= !p;
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free (p);
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return result;]])],
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[gl_cv_func_realloc_0_nonnull=yes],
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[gl_cv_func_realloc_0_nonnull=no],
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[AS_CASE([$host_os],
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[# Guess yes on platforms where we know the result.
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freebsd* | netbsd* | openbsd* | darwin* | bitrig* \
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| *-musl* | midipix* | midnightbsd* \
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| hpux* | solaris* | cygwin*],
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[gl_cv_func_realloc_0_nonnull="guessing yes"],
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[# Guess as follows if we don't know.
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gl_cv_func_realloc_0_nonnull=$gl_cross_guess_normal])])])
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AS_CASE([$gl_cv_func_realloc_0_nonnull],
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[*yes],
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[AC_DEFINE([HAVE_REALLOC_0_NONNULL], [1],
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[Define to 1 if realloc (..., 0) returns nonnull.])],
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[AS_CASE([$gl_cv_func_realloc_sanitize,$gl_cv_malloc_ptrdiff,$gl_cv_func_malloc_posix,$host],
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[yes,*,*,* | *,no,*,* | *,*,*no,* | *,*,*,aarch64c-*-freebsd*],
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[REPLACE_REALLOC_FOR_REALLOC_POSIX=1],
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[# Optimize for common case of glibc 2.1.1+ and compatibles.
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REPLACE_REALLOC_FOR_REALLOC_POSIX=2])])
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])
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