Add an autoconf test for whether unaligned int access is permitted.

It works on macos, and works correctly when I twiddle the test code to
generate a spurious segfault.  Will it work anywhere else?


svn:r1329
This commit is contained in:
Nick Mathewson 2004-03-21 04:14:06 +00:00
parent f608b85ddf
commit b69f5f3e1b
3 changed files with 15 additions and 2 deletions

View File

@ -163,6 +163,19 @@ AC_CHECK_SIZEOF(long)
AC_CHECK_SIZEOF(long long)
AC_CHECK_SIZEOF(__int64)
# Now, let's see about alignment requirements
AC_CACHE_CHECK([whether unaligned int access is allowed], tor_cv_unaligned_ok,
[AC_RUN_IFELSE([AC_LANG_SOURCE(
[[int main () { char s[] = "A\x00\x00\x00\x00\x00\x00\x00";
return *(int*)(&s[1]); }]])],
[tor_cv_unaligned_ok=yes],
[tor_cv_unaligned_ok=no],
[tor_cv_unaligned_ok=cross])])
if test tor_cv_unaligned_ok = yes; then
AC_DEFINE([UNALIGNED_INT_ACCESS_OK], 1,
[Define to 1 iff unaligned int access is allowed])
fi
# $prefix stores the value of the --prefix command line option, or
# NONE if the option wasn't set. In the case that it wasn't set, make
# it be the default, so that we can use it to expand directories now.

View File

@ -86,7 +86,7 @@ void tor_strlower(char *s)
}
}
#ifndef UNALIGNED_ACCESS_OK
#ifndef UNALIGNED_INT_ACCESS_OK
uint16_t get_uint16(char *cp)
{
uint16_t v;

View File

@ -43,7 +43,7 @@ char *tor_strndup(const char *s, size_t n);
#define tor_free(p) do {if(p) {free(p); (p)=NULL;}} while(0)
void tor_strlower(char *s);
#ifdef UNALIGNED_ACCESS_OK
#ifdef UNALIGNED_INT_ACCESS_OK
/* XXX Not actually used yet, but would probably be faster on non-sun
* hardare.
*/