Mercurial > gnulib
view m4/ilogbl.m4 @ 40214:452ab00796c7
Fix undefined behaviour.
* lib/bitrotate.h (rotl16, rotr16, rotl8, rotr8): Case x to
'unsigned int', to avoid shift operations on 'int'.
* lib/xmemdup0.c (xmemdup0): Don't invoke memcpy with a zero size.
* tests/test-count-leading-zeros.c (main): Use a random number that has
as many bits as TYPE, not only 2*15 or 2*31 bits.
* tests/test-count-trailing-zeros.c (main): Likewise.
* tests/test-count-one-bits.c (main): Likewise.
* tests/test-memmem.c: Don't include "null-ptr.h".
(main): Use zerosize_ptr() instead of null_ptr().
* modules/memmem-tests (Files): Remove tests/null-ptr.h.
author | Bruno Haible <bruno@clisp.org> |
---|---|
date | Sat, 09 Mar 2019 20:32:25 +0100 |
parents | e2e6dc79463b |
children |
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# ilogbl.m4 serial 3 dnl Copyright (C) 2010-2019 Free Software Foundation, Inc. dnl This file is free software; the Free Software Foundation dnl gives unlimited permission to copy and/or distribute it, dnl with or without modifications, as long as this notice is preserved. AC_DEFUN([gl_FUNC_ILOGBL], [ AC_REQUIRE([gl_MATH_H_DEFAULTS]) AC_REQUIRE([gl_LONG_DOUBLE_VS_DOUBLE]) AC_REQUIRE([gl_FUNC_ILOGB]) dnl Persuade glibc <math.h> to declare ilogbl(). AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS]) dnl Test whether ilogbl() exists. Assume that ilogbl(), if it exists, is dnl defined in the same library as ilogb(). save_LIBS="$LIBS" LIBS="$LIBS $ILOGB_LIBM" AC_CACHE_CHECK([for ilogbl], [gl_cv_func_ilogbl], [ AC_LINK_IFELSE( [AC_LANG_PROGRAM( [[#ifndef __NO_MATH_INLINES # define __NO_MATH_INLINES 1 /* for glibc */ #endif #include <math.h> int (*funcptr) (long double) = ilogbl; long double x;]], [[return (funcptr (x) % 2) == 0 || (ilogbl (x) % 2) == 0;]])], [gl_cv_func_ilogbl=yes], [gl_cv_func_ilogbl=no]) ]) LIBS="$save_LIBS" if test $gl_cv_func_ilogbl = yes; then ILOGBL_LIBM="$ILOGB_LIBM" save_LIBS="$LIBS" LIBS="$LIBS $ILOGBL_LIBM" gl_FUNC_ILOGBL_WORKS LIBS="$save_LIBS" case "$gl_cv_func_ilogbl_works" in *yes) ;; *) REPLACE_ILOGBL=1 ;; esac else HAVE_ILOGBL=0 fi if test $HAVE_ILOGBL = 0 || test $REPLACE_ILOGBL = 1; then dnl Find libraries needed to link lib/ilogbl.c. if test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 1; then ILOGBL_LIBM="$ILOGB_LIBM" else AC_REQUIRE([gl_FUNC_FREXPL]) AC_REQUIRE([gl_FUNC_ISNANL]) ILOGBL_LIBM= dnl Append $FREXPL_LIBM to ILOGBL_LIBM, avoiding gratuitous duplicates. case " $ILOGBL_LIBM " in *" $FREXPL_LIBM "*) ;; *) ILOGBL_LIBM="$ILOGBL_LIBM $FREXPL_LIBM" ;; esac dnl Append $ISNANL_LIBM to ILOGBL_LIBM, avoiding gratuitous duplicates. case " $ILOGBL_LIBM " in *" $ISNANL_LIBM "*) ;; *) ILOGBL_LIBM="$ILOGBL_LIBM $ISNANL_LIBM" ;; esac fi fi AC_SUBST([ILOGBL_LIBM]) ]) dnl Test whether ilogbl() works. dnl On Haiku 2017, it returns i-2 instead of i-1 for values between dnl ca. 2^-16444 and ca. 2^-16382. AC_DEFUN([gl_FUNC_ILOGBL_WORKS], [ AC_REQUIRE([AC_PROG_CC]) AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles AC_CACHE_CHECK([whether ilogbl works], [gl_cv_func_ilogbl_works], [ AC_RUN_IFELSE( [AC_LANG_SOURCE([[ #include <float.h> #include <math.h> /* Override the values of <float.h>, like done in float.in.h. */ #if defined __i386__ && (defined __BEOS__ || defined __OpenBSD__) # undef LDBL_MIN_EXP # define LDBL_MIN_EXP (-16381) #endif #if defined __i386__ && (defined __FreeBSD__ || defined __DragonFly__) # undef LDBL_MIN_EXP # define LDBL_MIN_EXP (-16381) #endif #if (defined _ARCH_PPC || defined _POWER) && defined _AIX && (LDBL_MANT_DIG == 106) && defined __GNUC__ # undef LDBL_MIN_EXP # define LDBL_MIN_EXP DBL_MIN_EXP #endif #if defined __sgi && (LDBL_MANT_DIG >= 106) # if defined __GNUC__ # undef LDBL_MIN_EXP # define LDBL_MIN_EXP DBL_MIN_EXP # endif #endif volatile long double x; static int dummy (long double x) { return 0; } int main (int argc, char *argv[]) { int (* volatile my_ilogbl) (long double) = argc ? ilogbl : dummy; int result = 0; /* This test fails on Haiku 2017. */ { int i; for (i = 1, x = (long double)1.0; i >= LDBL_MIN_EXP-100 && x > (long double)0.0; i--, x *= (long double)0.5) if (my_ilogbl (x) != i - 1) { result |= 1; break; } } return result; } ]])], [gl_cv_func_ilogbl_works=yes], [gl_cv_func_ilogbl_works=no], [case "$host_os" in haiku*) gl_cv_func_ilogbl_works="guessing no" ;; # Guess yes on native Windows. mingw*) gl_cv_func_ilogbl_works="guessing yes" ;; *) gl_cv_func_ilogbl_works="guessing yes" ;; esac ]) ]) ])