diff options
Diffstat (limited to 'gnulib/import/m4/memchr.m4')
| -rw-r--r-- | gnulib/import/m4/memchr.m4 | 46 |
1 files changed, 35 insertions, 11 deletions
diff --git a/gnulib/import/m4/memchr.m4 b/gnulib/import/m4/memchr.m4 index 25d32f0..c12d20a 100644 --- a/gnulib/import/m4/memchr.m4 +++ b/gnulib/import/m4/memchr.m4 @@ -1,11 +1,13 @@ -# memchr.m4 serial 12 -dnl Copyright (C) 2002-2004, 2009-2016 Free Software Foundation, Inc. +# memchr.m4 serial 15 +dnl Copyright (C) 2002-2004, 2009-2019 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_ONCE([gl_FUNC_MEMCHR], [ + AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles + dnl Check for prerequisites for memory fence checks. gl_FUNC_MMAP_ANON AC_CHECK_HEADERS_ONCE([sys/mman.h]) @@ -23,10 +25,12 @@ AC_DEFUN_ONCE([gl_FUNC_MEMCHR], if test $HAVE_MEMCHR = 1; then # Detect platform-specific bugs in some versions of glibc: # memchr should not dereference anything with length 0 - # http://bugzilla.redhat.com/499689 + # https://bugzilla.redhat.com/show_bug.cgi?id=499689 # memchr should not dereference overestimated length after a match - # http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=521737 - # http://sourceware.org/bugzilla/show_bug.cgi?id=10162 + # https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=521737 + # https://sourceware.org/bugzilla/show_bug.cgi?id=10162 + # memchr should cast the second argument to 'unsigned char'. + # This bug exists in Android 4.3. # Assume that memchr works on platforms that lack mprotect. AC_CACHE_CHECK([whether memchr works], [gl_cv_func_memchr_works], [AC_RUN_IFELSE([AC_LANG_PROGRAM([[ @@ -72,13 +76,33 @@ AC_DEFUN_ONCE([gl_FUNC_MEMCHR], if (memchr (fence - 1, 0, 3) != fence - 1) result |= 4; } + /* Test against bug on Android 4.3. */ + { + char input[3]; + input[0] = 'a'; + input[1] = 'b'; + input[2] = 'c'; + if (memchr (input, 0x789abc00 | 'b', 3) != input + 1) + result |= 8; + } return result; -]])], [gl_cv_func_memchr_works=yes], [gl_cv_func_memchr_works=no], - [dnl Be pessimistic for now. - gl_cv_func_memchr_works="guessing no"])]) - if test "$gl_cv_func_memchr_works" != yes; then - REPLACE_MEMCHR=1 - fi +]])], + [gl_cv_func_memchr_works=yes], + [gl_cv_func_memchr_works=no], + [case "$host_os" in + # Guess no on Android. + linux*-android*) gl_cv_func_memchr_works="guessing no" ;; + # Guess yes on native Windows. + mingw*) gl_cv_func_memchr_works="guessing yes" ;; + # If we don't know, obey --enable-cross-guesses. + *) gl_cv_func_memchr_works="$gl_cross_guess_normal" ;; + esac + ]) + ]) + case "$gl_cv_func_memchr_works" in + *yes) ;; + *) REPLACE_MEMCHR=1 ;; + esac fi ]) |