From ea9c2009115d7e00732f5ad316c10a171fc66a53 Mon Sep 17 00:00:00 2001 From: Nick Alcock Date: Mon, 27 Sep 2021 20:31:21 +0100 Subject: [PATCH] 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 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. --- 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 + + 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 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: *; }; -- 2.30.2