Use a nicely written autoconf macro to determine the sign of a type

This beats our old implementation, which wouldn't work when cross-compiling
This commit is contained in:
Nick Mathewson 2013-02-07 16:23:48 -05:00
parent e5b07ba179
commit 0e597471af
5 changed files with 68 additions and 22 deletions

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@ -7,6 +7,8 @@
# 1.9 means we require automake vesion 1.9
AUTOMAKE_OPTIONS = foreign 1.9 subdir-objects
ACLOCAL_AMFLAGS = -I m4
noinst_LIBRARIES=
EXTRA_DIST=
noinst_HEADERS=

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@ -17,7 +17,7 @@ fi
set -e
# Run this to generate all the initial makefiles, etc.
aclocal && \
aclocal -I m4 && \
autoheader && \
autoconf && \
automake --add-missing --copy

4
changes/signof_enum Normal file
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@ -0,0 +1,4 @@
o Code simplifications and refactoring:
- Use Ville Laurikari's implementation of AX_CHECK_SIGN() to determine
the signs of types during autoconf. This is better than our old
approach, which didn't work when cross-compiling.

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@ -5,6 +5,7 @@ dnl See LICENSE for licensing information
AC_INIT([tor],[0.2.4.10-alpha-dev])
AC_CONFIG_SRCDIR([src/or/main.c])
AC_CONFIG_MACRO_DIR([m4])
AM_INIT_AUTOMAKE
m4_ifdef([AM_SILENT_RULES], [AM_SILENT_RULES([yes])])
AC_CONFIG_HEADERS([orconfig.h])
@ -957,8 +958,9 @@ AC_CHECK_TYPES([rlim_t], , ,
#endif
])
AC_CACHE_CHECK([whether time_t is signed], tor_cv_time_t_signed, [
AC_RUN_IFELSE([AC_LANG_SOURCE([
AX_CHECK_SIGN([time_t],
[ AC_DEFINE(TIME_T_IS_SIGNED, 1, [Define if time_t is signed]) ],
[ : ], [
#ifdef HAVE_SYS_TYPES_H
#include <sys/types.h>
#endif
@ -968,32 +970,16 @@ AC_RUN_IFELSE([AC_LANG_SOURCE([
#ifdef HAVE_TIME_H
#include <time.h>
#endif
int main(int c, char**v) { if (((time_t)-1)<0) return 1; else return 0; }])],
tor_cv_time_t_signed=no, tor_cv_time_t_signed=yes, tor_cv_time_t_signed=cross)
])
if test "$tor_cv_time_t_signed" = cross; then
AC_MSG_NOTICE([Cross compiling: assuming that time_t is signed.])
fi
if test "$tor_cv_time_t_signed" != no; then
AC_DEFINE([TIME_T_IS_SIGNED], 1,
[Define to 1 iff time_t is signed])
fi
AC_CACHE_CHECK([whether size_t is signed], tor_cv_size_t_signed, [
AC_RUN_IFELSE([AC_LANG_SOURCE([
AX_CHECK_SIGN([size_t],
[ tor_cv_size_t_signed=yes ],
[ tor_cv_size_t_signed=no ], [
#ifdef HAVE_SYS_TYPES_H
#include <sys/types.h>
#endif
int main(int c, char**v) { if (((size_t)-1)<0) return 1; else return 0; }])],
tor_cv_size_t_signed=no, tor_cv_size_t_signed=yes, tor_cv_size_t_signed=cross)
])
if test "$tor_cv_size_t_signed" = cross; then
AC_MSG_NOTICE([Cross compiling: assuming that size_t is not signed.])
fi
if test "$tor_cv_size_t_signed" = yes; then
AC_MSG_ERROR([You have a signed size_t; that's grossly nonconformant.])
fi

54
m4/ax_check_sign.m4 Normal file
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@ -0,0 +1,54 @@
# ===========================================================================
# http://www.gnu.org/software/autoconf-archive/ax_check_sign.html
# ===========================================================================
#
# SYNOPSIS
#
# AX_CHECK_SIGN (TYPE, [ACTION-IF-SIGNED], [ACTION-IF-UNSIGNED], [INCLUDES])
#
# DESCRIPTION
#
# Checks whether TYPE is signed or not. If no INCLUDES are specified, the
# default includes are used. If ACTION-IF-SIGNED is given, it is
# additional shell code to execute when the type is signed. If
# ACTION-IF-UNSIGNED is given, it is executed when the type is unsigned.
#
# This macro assumes that the type exists. Therefore the existence of the
# type should be checked before calling this macro. For example:
#
# AC_CHECK_HEADERS([wchar.h])
# AC_CHECK_TYPE([wchar_t],,[ AC_MSG_ERROR([Type wchar_t not found.]) ])
# AX_CHECK_SIGN([wchar_t],
# [ AC_DEFINE(WCHAR_T_SIGNED, 1, [Define if wchar_t is signed]) ],
# [ AC_DEFINE(WCHAR_T_UNSIGNED, 1, [Define if wchar_t is unsigned]) ], [
# #ifdef HAVE_WCHAR_H
# #include <wchar.h>
# #endif
# ])
#
# LICENSE
#
# Copyright (c) 2008 Ville Laurikari <vl@iki.fi>
#
# Copying and distribution of this file, with or without modification, are
# permitted in any medium without royalty provided the copyright notice
# and this notice are preserved. This file is offered as-is, without any
# warranty.
#serial 6
AU_ALIAS([VL_CHECK_SIGN], [AX_CHECK_SIGN])
AC_DEFUN([AX_CHECK_SIGN], [
typename=`echo $1 | sed "s/@<:@^a-zA-Z0-9_@:>@/_/g"`
AC_CACHE_CHECK([whether $1 is signed], ax_cv_decl_${typename}_signed, [
AC_TRY_COMPILE([$4],
[ int foo @<:@ 1 - 2 * !((($1) -1) < 0) @:>@ ],
[ eval "ax_cv_decl_${typename}_signed=\"yes\"" ],
[ eval "ax_cv_decl_${typename}_signed=\"no\"" ])])
symbolname=`echo $1 | sed "s/@<:@^a-zA-Z0-9_@:>@/_/g" | tr "a-z" "A-Z"`
if eval "test \"\${ax_cv_decl_${typename}_signed}\" = \"yes\""; then
$2
elif eval "test \"\${ax_cv_decl_${typename}_signed}\" = \"no\""; then
$3
fi
])dnl