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Diffstat (limited to 'm4/ax_check_vscript.m4')
| -rw-r--r-- | m4/ax_check_vscript.m4 | 142 |
1 files changed, 142 insertions, 0 deletions
diff --git a/m4/ax_check_vscript.m4 b/m4/ax_check_vscript.m4 new file mode 100644 index 0000000..219ad22 --- /dev/null +++ b/m4/ax_check_vscript.m4 @@ -0,0 +1,142 @@ +# =========================================================================== +# http://www.gnu.org/software/autoconf-archive/ax_check_vscript.html +# =========================================================================== +# +# SYNOPSIS +# +# AX_CHECK_VSCRIPT +# +# DESCRIPTION +# +# Check whether the linker supports version scripts. Version scripts are +# used when building shared libraries to bind symbols to version nodes +# (helping to detect incompatibilities) or to limit the visibility of +# non-public symbols. +# +# Output: +# +# If version scripts are supported, VSCRIPT_LDFLAGS will contain the +# appropriate flag to pass to the linker. On GNU systems this would +# typically be "-Wl,--version-script", and on Solaris it would typically +# be "-Wl,-M". +# +# Two Automake conditionals are also set: +# +# HAVE_VSCRIPT is true if the linker supports version scripts with +# entries that use simple wildcards, like "local: *". +# +# HAVE_VSCRIPT_COMPLEX is true if the linker supports version scripts with +# pattern matching wildcards, like "global: Java_*". +# +# On systems that do not support symbol versioning, such as Mac OS X, both +# conditionals will be false. They will also be false if the user passes +# "--disable-symvers" on the configure command line. +# +# Example: +# +# configure.ac: +# +# AX_CHECK_VSCRIPT +# +# Makefile.am: +# +# if HAVE_VSCRIPT +# libfoo_la_LDFLAGS += $(VSCRIPT_LDFLAGS),@srcdir@/libfoo.map +# endif +# +# if HAVE_VSCRIPT_COMPLEX +# libbar_la_LDFLAGS += $(VSCRIPT_LDFLAGS),@srcdir@/libbar.map +# endif +# +# LICENSE +# +# Copyright (c) 2014 Kevin Cernekee <cernekee@gmail.com> +# +# Copying and distribution of this file, with or without modification, are +# permitted in any medium without royalty provided the copyright notice +# and this notice are preserved. This file is offered as-is, without any +# warranty. + +#serial 1 + +# _AX_CHECK_VSCRIPT(flag, global-sym, action-if-link-succeeds, [junk-file=no]) +AC_DEFUN([_AX_CHECK_VSCRIPT], [ + AC_LANG_PUSH([C]) + ax_check_vscript_save_flags="$LDFLAGS" + echo "V1 { global: $2; local: *; };" > conftest.map + AS_IF([test x$4 = xyes], [ + echo "{" >> conftest.map + ]) + LDFLAGS="$LDFLAGS -Wl,$1,conftest.map" + AC_LINK_IFELSE([AC_LANG_PROGRAM([[int show, hide;]], [])], [$3]) + LDFLAGS="$ax_check_vscript_save_flags" + rm -f conftest.map + AC_LANG_POP([C]) +]) dnl _AX_CHECK_VSCRIPT + +AC_DEFUN([AX_CHECK_VSCRIPT], [ + + AC_ARG_ENABLE([symvers], + AS_HELP_STRING([--disable-symvers], + [disable library symbol versioning [default=auto]]), + [want_symvers=$enableval], + [want_symvers=yes] + ) + + AS_IF([test x$want_symvers = xyes], [ + + dnl First test --version-script and -M with a simple wildcard. + + AC_CACHE_CHECK([linker version script flag], ax_cv_check_vscript_flag, [ + ax_cv_check_vscript_flag=unsupported + _AX_CHECK_VSCRIPT([--version-script], [show], [ + ax_cv_check_vscript_flag=--version-script + ]) + AS_IF([test x$ax_cv_check_vscript_flag = xunsupported], [ + _AX_CHECK_VSCRIPT([-M], [show], [ax_cv_check_vscript_flag=-M]) + ]) + + dnl The linker may interpret -M (no argument) as "produce a load map." + dnl If "-M conftest.map" doesn't fail when conftest.map contains + dnl obvious syntax errors, assume this is the case. + + AS_IF([test x$ax_cv_check_vscript_flag != xunsupported], [ + _AX_CHECK_VSCRIPT([$ax_cv_check_vscript_flag], [show], + [ax_cv_check_vscript_flag=unsupported], [yes]) + ]) + ]) + + dnl If the simple wildcard worked, retest with a complex wildcard. + + AS_IF([test x$ax_cv_check_vscript_flag != xunsupported], [ + ax_check_vscript_flag=$ax_cv_check_vscript_flag + AC_CACHE_CHECK([if version scripts can use complex wildcards], + ax_cv_check_vscript_complex_wildcards, [ + ax_cv_check_vscript_complex_wildcards=no + _AX_CHECK_VSCRIPT([$ax_cv_check_vscript_flag], [sh*], [ + ax_cv_check_vscript_complex_wildcards=yes]) + ]) + ax_check_vscript_complex_wildcards="$ax_cv_check_vscript_complex_wildcards" + ], [ + ax_check_vscript_flag= + ax_check_vscript_complex_wildcards=no + ]) + ], [ + AC_MSG_CHECKING([linker version script flag]) + AC_MSG_RESULT([disabled]) + + ax_check_vscript_flag= + ax_check_vscript_complex_wildcards=no + ]) + + AS_IF([test x$ax_check_vscript_flag != x], [ + VSCRIPT_LDFLAGS="-Wl,$ax_check_vscript_flag" + AC_SUBST([VSCRIPT_LDFLAGS]) + ]) + + AM_CONDITIONAL([HAVE_VSCRIPT], + [test x$ax_check_vscript_flag != x]) + AM_CONDITIONAL([HAVE_VSCRIPT_COMPLEX], + [test x$ax_check_vscript_complex_wildcards = xyes]) + +]) dnl AX_CHECK_VSCRIPT |