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 $NM, a path might have been
provided: so we use the user-specified path if there was one, and
otherwise do the path search as usual. (If the nm specified doesn't
work, this might lead to a few extra pointless path searches -- but
the test is going to fail anyway, so that's not a problem.)
(Tested on Solaris 11.4 with NM unset, and set to nm, /usr/bin/nm,
my-nm where my-nm is a symlink to /usr/bin/nm on the PATH, and
/not-on-the-path/my-nm where *that* is a symlink to /usr/bin/nm.
With NM=/usr/bin/nm, Libtool 2.4.6 sees 41 failures, 36 unexpected
and not present if NM is unset; all are fixed by this commit.)
* m4/libtool.m4 (LT_PATH_NM): Try BSDization flags with a user-provided
NM, if there is one. Run nm on itself, not on /dev/null, to avoid
errors from nms that refuse to work on non-regular files. Remove
other workarounds for this problem. Strip out blank lines from the
nm output.
Signed-off-by: Nick Alcock
---
m4/libtool.m4 | 85 ++-
1 file changed, 43 insertions(+), 42 deletions(-)
diff --git a/m4/libtool.m4 b/m4/libtool.m4
index fea1a41a..cb1229d0 100644
--- a/m4/libtool.m4
+++ b/m4/libtool.m4
@@ -3660,48 +3660,49 @@ AC_DEFUN([LT_PATH_NM],
[AC_REQUIRE([AC_PROG_CC])dnl
AC_CACHE_CHECK([for BSD- or MS-compatible name lister (nm)], lt_cv_path_NM,
[if test -n "$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 2
- ;;
- *)
- case `"$tmp_nm" -p /dev/null 2>&1 | sed '1q'` in
- */dev/null*)
- lt_cv_path_NM="$tmp_nm -p"
- break 2
- ;;
- *)
- 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";;
+
