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* [binutils-gdb] libctf: try several possibilities for linker versioning flags
@ 2021-09-27 19:34 Nick Alcock
0 siblings, 0 replies; only message in thread
From: Nick Alcock @ 2021-09-27 19:34 UTC (permalink / raw)
To: bfd-cvs, gdb-cvs
https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=ea9c2009115d7e00732f5ad316c10a171fc66a53
commit ea9c2009115d7e00732f5ad316c10a171fc66a53
Author: Nick Alcock <nick.alcock@oracle.com>
Date: Mon Sep 27 20:31:21 2021 +0100
libctf: try several possibilities for linker versioning flags
Checking for linker versioning by just grepping ld --help output for
mentions of --version-script is inadequate now that Solaris 11.4
implements a --version-script with different semantics. Try linking a
test program with a small wildcard-using version script with each
supported set of flags in turn, to make sure that linker versioning is
not only advertised but actually works.
The Solaris "GNU-compatible" linker versioning is not quite
GNU-compatible enough, but we can work around the differences by
generating a new version script that removes the comments from the
original (Solaris ld requires #-style comments), and making another
version script for libctf-nonbfd in particular which doesn't mention any
of the symbols that appear in libctf.la, to avoid Solaris ld introducing
corresponding new NOTYPE symbols to match the version script.
libctf/ChangeLog
2021-09-27 Nick Alcock <nick.alcock@oracle.com>
PR libctf/27967
* configure.ac (VERSION_FLAGS): Replace with...
(ac_cv_libctf_version_script): ... this multiple test.
(VERSION_FLAGS_NOBFD): Substitute this too.
* Makefile.am (libctf_nobfd_la_LDFLAGS): Use it. Split out...
(libctf_ldflags_nover): ... non-versioning flags here.
(libctf_la_LDFLAGS): Use it.
* libctf.ver: Give every symbol not in libctf-nobfd a comment on
the same line noting as much.
Diff:
---
libctf/ChangeLog | 12 ++++++++++++
libctf/Makefile.am | 5 +++--
libctf/configure.ac | 46 +++++++++++++++++++++++++++++++++++++++++++---
libctf/libctf.ver | 10 ++++------
4 files changed, 62 insertions(+), 11 deletions(-)
diff --git a/libctf/ChangeLog b/libctf/ChangeLog
index da361e4450d..03d8506f92b 100644
--- a/libctf/ChangeLog
+++ b/libctf/ChangeLog
@@ -1,3 +1,15 @@
+2021-09-27 Nick Alcock <nick.alcock@oracle.com>
+
+ PR libctf/27967
+ * configure.ac (VERSION_FLAGS): Replace with...
+ (ac_cv_libctf_version_script): ... this multiple test.
+ (VERSION_FLAGS_NOBFD): Substitute this too.
+ * Makefile.am (libctf_nobfd_la_LDFLAGS): Use it. Split out...
+ (libctf_ldflags_nover): ... non-versioning flags here.
+ (libctf_la_LDFLAGS): Use it.
+ * libctf.ver: Give every symbol not in libctf-nobfd a comment on
+ the same line noting as much.
+
2021-09-27 Nick Alcock <nick.alcock@oracle.com>
PR libctf/27360
diff --git a/libctf/Makefile.am b/libctf/Makefile.am
index 970b66dc608..31fcb5d320a 100644
--- a/libctf/Makefile.am
+++ b/libctf/Makefile.am
@@ -42,7 +42,8 @@ noinst_LTLIBRARIES = libctf.la libctf-nobfd.la
endif
libctf_nobfd_la_LIBADD = @CTF_LIBADD@ $(ZLIB)
-libctf_nobfd_la_LDFLAGS = -version-info 0:0:0 @SHARED_LDFLAGS@ @VERSION_FLAGS@
+libctf_ldflags_nover = -version-info 0:0:0 @SHARED_LDFLAGS@
+libctf_nobfd_la_LDFLAGS = $(libctf_ldflags_nover) @VERSION_FLAGS_NOBFD@
libctf_nobfd_la_CPPFLAGS = $(AM_CPPFLAGS) -DNOBFD=1
libctf_nobfd_la_SOURCES = ctf-archive.c ctf-dump.c ctf-create.c ctf-decl.c ctf-error.c \
ctf-hash.c ctf-labels.c ctf-dedup.c ctf-link.c ctf-lookup.c \
@@ -58,7 +59,7 @@ endif
# references in there get picked up.
libctf_la_LIBADD = @CTF_LIBADD@ ../bfd/libbfd.la $(libctf_nobfd_la_LIBADD)
libctf_la_CPPFLAGS = $(AM_CPPFLAGS) -DNOBFD=0
-libctf_la_LDFLAGS = $(libctf_nobfd_la_LDFLAGS)
+libctf_la_LDFLAGS = $(libctf_ldflags_nover) @VERSION_FLAGS@
libctf_la_SOURCES = $(libctf_nobfd_la_SOURCES) ctf-open-bfd.c
# Setup the testing framework, if you have one
diff --git a/libctf/configure.ac b/libctf/configure.ac
index 80644b89d67..4e12a4fa8f6 100644
--- a/libctf/configure.ac
+++ b/libctf/configure.ac
@@ -219,11 +219,51 @@ fi`
AM_CONDITIONAL(TCL_TRY, test "${ac_cv_libctf_tcl_try}" = yes)
# Use a version script, if possible, or an -export-symbols-regex otherwise.
-VERSION_FLAGS='-export-symbols-regex ctf_.*'
-if $LD --help 2>&1 | grep -- --version-script >/dev/null; then
- VERSION_FLAGS="-Wl,--version-script='$srcdir/libctf.ver'"
+decommented_version_script=
+AC_CACHE_CHECK([for linker versioning flags], [ac_cv_libctf_version_script],
+ [echo 'FOO { global: mai*; local: ctf_fo*; };' > conftest.ver
+ old_LDFLAGS="$LDFLAGS"
+ old_CFLAGS="$CFLAGS"
+ LDFLAGS="$LDFLAGS -shared -Wl,--version-script=conftest.ver"
+ CFLAGS="$CFLAGS -fPIC"
+ AC_LINK_IFELSE([AC_LANG_SOURCE([[int ctf_foo (void) { return 0; }
+ int main (void) { return ctf_foo(); }]])],
+ [ac_cv_libctf_version_script="-Wl,--version-script='$srcdir/libctf.ver'"],
+ [])
+ LDFLAGS="$old_LDFLAGS"
+
+ if test -z "$ac_cv_libctf_version_script"; then
+ LDFLAGS="$LDFLAGS -shared -Wl,-B,local -Wl,-z,gnu-version-script=conftest.ver"
+ AC_LINK_IFELSE([AC_LANG_SOURCE([[int ctf_foo (void) { return 0; }
+ int main (void) { return ctf_foo(); }]])],
+ [ac_cv_libctf_version_script="-Wl,-B,local -Wl,-z,gnu-version-script"
+ decommented_version_script=t],
+ [])
+ LDFLAGS="$old_LDFLAGS"
+ fi
+ CFLAGS="$old_CFLAGS"
+
+ if test -z "$ac_cv_libctf_version_script"; then
+ ac_cv_libctf_version_script='-export-symbols-regex ctf_.*'
+ fi
+ rm -f conftest.ver])
+if test -n "$decommented_version_script"; then
+ # Solaris's version scripts use shell-style comments rather than the C-style
+ # used by GNU ld. Use cpp to strip the comments out. (cpp exists under this
+ # name on all platforms that support ld -z gnu-version-script.)
+ # Also ensure that no symbols exist in the version script for libctf-nobfd.so
+ # that do not exist in the shared library itself, since some linkers add such
+ # symbols with type NOTYPE.
+ /lib/cpp < $srcdir/libctf.ver > libctf-decommented.ver
+ grep -v 'libctf only' $srcdir/libctf.ver | /lib/cpp > libctf-nobfd-decommented.ver
+ VERSION_FLAGS="$ac_cv_libctf_version_script='libctf-decommented.ver'"
+ VERSION_FLAGS_NOBFD="$ac_cv_libctf_version_script='libctf-nobfd-decommented.ver'"
+else
+ VERSION_FLAGS="$ac_cv_libctf_version_script"
+ VERSION_FLAGS_NOBFD="$ac_cv_libctf_version_script"
fi
AC_SUBST(VERSION_FLAGS)
+AC_SUBST(VERSION_FLAGS_NOBFD)
AC_CONFIG_FILES(Makefile)
AC_CONFIG_HEADERS(config.h)
diff --git a/libctf/libctf.ver b/libctf/libctf.ver
index 0b182f37228..602c13fba17 100644
--- a/libctf/libctf.ver
+++ b/libctf/libctf.ver
@@ -165,12 +165,10 @@ LIBCTF_1.0 {
ctf_link_shuffle_syms;
ctf_link_write;
- /* In libctf alone. */
-
- ctf_fdopen;
- ctf_open;
- ctf_bfdopen;
- ctf_bfdopen_ctfsect;
+ ctf_fdopen; /* libctf only. */
+ ctf_open; /* libctf only. */
+ ctf_bfdopen; /* libctf only. */
+ ctf_bfdopen_ctfsect; /* libctf only. */
local:
*;
};
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