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Merge from Gnulib for malloc, realloc checking

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* lib/autoconf/functions.m4 (_AC_FUNC_MALLOC_IF, _AC_FUNC_REALLOC_IF):
Add 3rd argument for cross-guessing; all callers changed.
Use ‘volatile’ so that compilers don’t second-guess.
Also guess yes on gnu*, midipix*, midnightbsd*.
This commit is contained in:
Paul Eggert 2024-10-28 21:27:35 -07:00
parent c40517146a
commit 1a449f4d79
1 changed files with 72 additions and 48 deletions
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120
lib/autoconf/functions.m4
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@ -968,30 +968,41 @@ fi
])
# _AC_FUNC_MALLOC_IF(IF-WORKS, IF-NOT)
# ------------------------------------
# If 'malloc (0)' properly handled, run IF-WORKS, otherwise, IF-NOT.
# _AC_FUNC_MALLOC_IF(IF-WORKS, IF-NOT, UNKNOWN-ASSUME)
# ----------------------------------------------------
# If 'malloc (0, 0)' returns nonnull, run IF-WORKS, otherwise, IF-NOT.
# If it is not known whether it works, assume the shell word UNKNOWN-ASSUME,
# which should end in "yes" or in something else.
AC_DEFUN([_AC_FUNC_MALLOC_IF],
[AC_REQUIRE([AC_CANONICAL_HOST])dnl for cross-compiles
AC_CACHE_CHECK([for GNU libc compatible malloc], ac_cv_func_malloc_0_nonnull,
[AC_RUN_IFELSE(
[AC_LANG_PROGRAM([[#include <stdlib.h>
]],
[[void *p = malloc (0);
int result = !p;
free (p);
return result;]])],
[ac_cv_func_malloc_0_nonnull=yes],
[ac_cv_func_malloc_0_nonnull=no],
[case "$host_os" in # ((
# Guess yes on platforms where we know the result.
*-gnu* | *-musl* | freebsd* | netbsd* | openbsd* | bitrig* \
| hpux* | solaris* | cygwin* | mingw* | windows* | msys* )
ac_cv_func_malloc_0_nonnull=yes ;;
# If we don't know, assume the worst.
*) ac_cv_func_malloc_0_nonnull=no ;;
esac])])
AS_IF([test $ac_cv_func_malloc_0_nonnull = yes], [$1], [$2])
[
AC_REQUIRE([AC_CANONICAL_HOST])dnl for cross-compiles
AC_CACHE_CHECK([whether malloc (0) returns nonnull],
[ac_cv_func_malloc_0_nonnull],
[AC_RUN_IFELSE(
[AC_LANG_PROGRAM(
[[#include <stdlib.h>
/* Use pmalloc to test; 'volatile' prevents the compiler
from optimizing the malloc call away. */
void *(*volatile pmalloc) (size_t) = malloc;]],
[[void *p = pmalloc (nbytes);
int result = !p;
free (p);
return result;]])
],
[ac_cv_func_malloc_0_nonnull=yes],
[ac_cv_func_malloc_0_nonnull=no],
[case "$host_os" in
# Guess yes on platforms where we know the result.
*-gnu* | freebsd* | netbsd* | openbsd* | bitrig* \
| gnu* | *-musl* | midipix* | midnightbsd* \
| hpux* | solaris* | cygwin* | mingw* | windows* | msys* )
ac_cv_func_malloc_0_nonnull="guessing yes" ;;
# Guess as follows if we don't know.
*) ac_cv_func_malloc_0_nonnull=$3 ;;
esac
])
])
AS_CASE([$ac_cv_func_malloc_0_nonnull], [*yes], [$1], [$2])
])# _AC_FUNC_MALLOC_IF
@ -1008,7 +1019,8 @@ AC_DEFUN([AC_FUNC_MALLOC],
[AC_DEFINE([HAVE_MALLOC], 0)
AC_LIBOBJ(malloc)
AC_DEFINE([malloc], [rpl_malloc],
[Define to rpl_malloc if the replacement function should be used.])])
[Define to rpl_malloc if the replacement function should be used.])],
["guessing no"])
])# AC_FUNC_MALLOC
@ -1472,30 +1484,41 @@ AU_ALIAS([AM_FUNC_OBSTACK], [AC_FUNC_OBSTACK])
# _AC_FUNC_REALLOC_IF(IF-WORKS, IF-NOT)
# -------------------------------------
# If 'realloc (0, 0)' is properly handled, run IF-WORKS, otherwise, IF-NOT.
# _AC_FUNC_REALLOC_IF(IF-WORKS, IF-NOT, UNKNOWN-ASSUME)
# -----------------------------------------------------
# If 'realloc (0, 0)' returns nonnull, run IF-WORKS, otherwise, IF-NOT.
# If it is not known whether it works, assume the shell word UNKNOWN-ASSUME,
# which should end in "yes" or in something else.
AC_DEFUN([_AC_FUNC_REALLOC_IF],
[AC_REQUIRE([AC_CANONICAL_HOST])dnl for cross-compiles
AC_CACHE_CHECK([for GNU libc compatible realloc], ac_cv_func_realloc_0_nonnull,
[AC_RUN_IFELSE(
[AC_LANG_PROGRAM([[#include <stdlib.h>
]],
[[void *p = realloc (0, 0);
int result = !p;
free (p);
return result;]])],
[ac_cv_func_realloc_0_nonnull=yes],
[ac_cv_func_realloc_0_nonnull=no],
[case "$host_os" in # ((
# Guess yes on platforms where we know the result.
*-gnu* | freebsd* | netbsd* | openbsd* | bitrig* \
| hpux* | solaris* | cygwin* | mingw* | windows* | msys* )
ac_cv_func_realloc_0_nonnull=yes ;;
# If we don't know, assume the worst.
*) ac_cv_func_realloc_0_nonnull=no ;;
esac])])
AS_IF([test $ac_cv_func_realloc_0_nonnull = yes], [$1], [$2])
[
AC_REQUIRE([AC_CANONICAL_HOST])dnl for cross-compiles
AC_CACHE_CHECK([whether realloc (0, 0) returns nonnull],
[ac_cv_func_realloc_0_nonnull],
[AC_RUN_IFELSE(
[AC_LANG_PROGRAM(
[[#include <stdlib.h>
/* Use prealloc to test; 'volatile' prevents the compiler
from optimizing the realloc call away. */
void *(*volatile prealloc) (void *, size_t) = realloc;]],
[[void *p = prealloc (n, n);
int result = !p;
free (p);
return result;]])
],
[ac_cv_func_realloc_0_nonnull=yes],
[ac_cv_func_realloc_0_nonnull=no],
[case "$host_os" in
# Guess yes on platforms where we know the result.
*-gnu* | freebsd* | netbsd* | openbsd* | bitrig* \
| gnu* | *-musl* | midipix* | midnightbsd* \
| hpux* | solaris* | cygwin* | mingw* | windows* | msys* )
ac_cv_func_realloc_0_nonnull="guessing yes" ;;
# Guess as follows if we don't know.
*) ac_cv_func_realloc_0_nonnull=$3 ;;
esac
])
])
AS_CASE([$ac_cv_func_realloc_0_nonnull], [*yes], [$1], [$2])
])# _AC_FUNC_REALLOC_IF
@ -1512,7 +1535,8 @@ AC_DEFUN([AC_FUNC_REALLOC],
[AC_DEFINE([HAVE_REALLOC], 0)
AC_LIBOBJ([realloc])
AC_DEFINE([realloc], [rpl_realloc],
[Define to rpl_realloc if the replacement function should be used.])])
[Define to rpl_realloc if the replacement function should be used.])],
["guessing no"])
])# AC_FUNC_REALLOC