From bef9ef8ca0f941d743c77cc55b5fe7985990b2a7 Mon Sep 17 00:00:00 2001 From: Nick Alcock Date: Mon, 27 Sep 2021 20:31:21 +0100 Subject: [PATCH] libtool.m4: fix nm BSD flag detection Libtool needs to get BSD-format (or MS-format) output out of the system nm, so that it can scan generated object files for symbol names for -export-symbols-regex support. Some nms need specific flags to turn on BSD-formatted output, so libtool checks for this in its AC_PATH_NM. Unfortunately the code to do this has a pair of interlocking flaws: - it runs the test by doing an nm of /dev/null. Some platforms reasonably refuse to do an nm on a device file, but before now this has only been worked around by assuming that the error message has a specific textual form emitted by Tru64 nm, and that getting this error means this is Tru64 nm and that nm -B would work to produce BSD-format output, even though the test never actually got anything but an error message out of nm -B. This is fixable by nm'ing *nm itself* (since we necessarily have a path to it). - the test is entirely skipped if NM is set in the environment, on the grounds that the user has overridden the test: but the user cannot reasonably be expected to know that libtool wants not only nm but also flags forcing BSD-format output. Worse yet, one such "user" is the top-level Cygnus configure script, which neither tests for nor specifies any BSD-format flags. So platforms needing BSD-format flags always fail to set them when run in a Cygnus tree, breaking -export-symbols-regex on such platforms. Libtool also needs to augment $LD on some platforms, but this is done unconditionally, augmenting whatever the user specified: the nm check should do the same. One wrinkle: if the user has overridden $NM, a path might have been provided: so we use the user-specified path if there was one, and otherwise do the path search as usual. (If the nm specified doesn't work, this might lead to a few extra pointless path searches -- but the test is going to fail anyway, so that's not a problem.) (Tested with NM unset, and set to nm, /usr/bin/nm, my-nm where my-nm is a symlink to /usr/bin/nm on the PATH, and /not-on-the-path/my-nm where *that* is a symlink to /usr/bin/nm.) ChangeLog 2021-09-27 Nick Alcock PR libctf/27967 * libtool.m4 (LT_PATH_NM): Try BSDization flags with a user-provided NM, if there is one. Run nm on itself, not on /dev/null, to avoid errors from nms that refuse to work on non-regular files. Remove other workarounds for this problem. Strip out blank lines from the nm output. --- ChangeLog | 9 ++++++ libtool.m4 | 88 ++++++++++++++++++++++++++++-------------------------- 2 files changed, 54 insertions(+), 43 deletions(-) diff --git a/ChangeLog b/ChangeLog index dd1ba3d66b5..afa6629abd1 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,12 @@ +2021-09-27 Nick Alcock + + PR libctf/27967 + * libtool.m4 (LT_PATH_NM): Try BSDization flags with a user-provided + NM, if there is one. Run nm on itself, not on /dev/null, to avoid + errors from nms that refuse to work on non-regular files. Remove + other workarounds for this problem. Strip out blank lines from the + nm output. + 2021-09-27 Nick Alcock PR libctf/27967 diff --git a/libtool.m4 b/libtool.m4 index 7a711249304..a216bb14e99 100644 --- a/libtool.m4 +++ b/libtool.m4 @@ -3200,53 +3200,55 @@ _LT_DECL([], [file_magic_cmd], [1], # LT_PATH_NM # ---------- -# find the pathname to a BSD- or MS-compatible name lister +# find the pathname to a BSD- or MS-compatible name lister, and any flags +# needed to make it compatible AC_DEFUN([LT_PATH_NM], [AC_REQUIRE([AC_PROG_CC])dnl AC_CACHE_CHECK([for BSD- or MS-compatible name lister (nm)], lt_cv_path_NM, [if test -n "$NM"; then - # Let the user override the test. - lt_cv_path_NM="$NM" -else - lt_nm_to_check="${ac_tool_prefix}nm" - if test -n "$ac_tool_prefix" && test "$build" = "$host"; then - lt_nm_to_check="$lt_nm_to_check nm" - fi - for lt_tmp_nm in $lt_nm_to_check; do - lt_save_ifs="$IFS"; IFS=$PATH_SEPARATOR - for ac_dir in $PATH /usr/ccs/bin/elf /usr/ccs/bin /usr/ucb /bin; do - IFS="$lt_save_ifs" - test -z "$ac_dir" && ac_dir=. - tmp_nm="$ac_dir/$lt_tmp_nm" - if test -f "$tmp_nm" || test -f "$tmp_nm$ac_exeext" ; then - # Check to see if the nm accepts a BSD-compat flag. - # Adding the `sed 1q' prevents false positives on HP-UX, which says: - # nm: unknown option "B" ignored - # Tru64's nm complains that /dev/null is an invalid object file - case `"$tmp_nm" -B /dev/null 2>&1 | sed '1q'` in - */dev/null* | *'Invalid file or object type'*) - lt_cv_path_NM="$tmp_nm -B" - break - ;; - *) - case `"$tmp_nm" -p /dev/null 2>&1 | sed '1q'` in - */dev/null*) - lt_cv_path_NM="$tmp_nm -p" - break - ;; - *) - lt_cv_path_NM=${lt_cv_path_NM="$tmp_nm"} # keep the first match, but - continue # so that we can try to find one that supports BSD flags - ;; - esac - ;; - esac - fi - done - IFS="$lt_save_ifs" - done - : ${lt_cv_path_NM=no} -fi]) + # Let the user override the nm to test. + lt_nm_to_check="$NM" + else + lt_nm_to_check="${ac_tool_prefix}nm" + if test -n "$ac_tool_prefix" && test "$build" = "$host"; then + lt_nm_to_check="$lt_nm_to_check nm" + fi + fi + for lt_tmp_nm in $lt_nm_to_check; do + lt_save_ifs="$IFS"; IFS=$PATH_SEPARATOR + for ac_dir in $PATH /usr/ccs/bin/elf /usr/ccs/bin /usr/ucb /bin; do + IFS="$lt_save_ifs" + test -z "$ac_dir" && ac_dir=. + case "$lt_tmp_nm" in + */*|*\\*) tmp_nm="$lt_tmp_nm";; + *) tmp_nm="$ac_dir/$lt_tmp_nm";; + esac + if test -f "$tmp_nm" || test -f "$tmp_nm$ac_exeext" ; then + # Check to see if the nm accepts a BSD-compat flag. + # Adding the `sed 1q' prevents false positives on HP-UX, which says: + # nm: unknown option "B" ignored + case `"$tmp_nm" -B "$tmp_nm" 2>&1 | grep -v '^ *$' | sed '1q'` in + *$tmp_nm*) lt_cv_path_NM="$tmp_nm -B" + break + ;; + *) + case `"$tmp_nm" -p "$tmp_nm" 2>&1 | grep -v '^ *$' | sed '1q'` in + *$tmp_nm*) + lt_cv_path_NM="$tmp_nm -p" + break + ;; + *) + lt_cv_path_NM=${lt_cv_path_NM="$tmp_nm"} # keep the first match, but + continue # so that we can try to find one that supports BSD flags + ;; + esac + ;; + esac + fi + done + IFS="$lt_save_ifs" + done + : ${lt_cv_path_NM=no}]) if test "$lt_cv_path_NM" != "no"; then NM="$lt_cv_path_NM" else -- 2.30.2