From 86abd6c1c063f490cb16e1b4bcd142ef0cb7fada Mon Sep 17 00:00:00 2001
From: Alexandre Duret-Lutz <adl@lrde.epita.fr>
Date: Tue, 10 Nov 2015 08:31:54 +0100
Subject: [PATCH] Use -Bsymbolic-functions and -Bsymbolic

This avoids dynamic lookups to resolve symbols inside the library, but
disallows symbol interposition.

* m4/symbolic.m4: New file.
* buddy/m4/symbolic.m4: New link.
* configure.ac, buddy/configure.ac: Add AX_SYMBOLIC.
* buddy/src/Makefile.am, iface/ltsmin/Makefile.am, src/Makefile.am,
wrap/python/Makefile.am: Link with $(SYMBOLIC_LDFLAGS).
---
 buddy/configure.ac       |  1 +
 buddy/m4/symbolic.m4     |  1 +
 buddy/src/Makefile.am    |  2 +-
 configure.ac             |  1 +
 iface/ltsmin/Makefile.am |  1 +
 m4/symbolic.m4           | 31 +++++++++++++++++++++++++++++++
 src/Makefile.am          |  2 +-
 wrap/python/Makefile.am  |  5 +++--
 8 files changed, 40 insertions(+), 4 deletions(-)
 create mode 120000 buddy/m4/symbolic.m4
 create mode 100644 m4/symbolic.m4

diff --git a/buddy/configure.ac b/buddy/configure.ac
index c3876b2b1..af7d1195d 100644
--- a/buddy/configure.ac
+++ b/buddy/configure.ac
@@ -19,6 +19,7 @@ AC_PROG_YACC
 AC_PROG_CXX
 
 LT_INIT([win32-dll])
+AX_BSYMBOLIC
 
 # Use -Werror since using -fvisibility under MinGW is only a warning.
 # (The option is ignored anyway since this does not make sense under windows).
diff --git a/buddy/m4/symbolic.m4 b/buddy/m4/symbolic.m4
new file mode 120000
index 000000000..fa1b28284
--- /dev/null
+++ b/buddy/m4/symbolic.m4
@@ -0,0 +1 @@
+../../m4/symbolic.m4
\ No newline at end of file
diff --git a/buddy/src/Makefile.am b/buddy/src/Makefile.am
index de770944d..ac4a4b247 100644
--- a/buddy/src/Makefile.am
+++ b/buddy/src/Makefile.am
@@ -5,7 +5,7 @@ BUDDY_FLAGS = -I$(top_builddir) -DVERSION=23 -DBUDDY_DLL_EXPORTS -DBUDDY_DLL
 lib_LTLIBRARIES = libbddx.la
 # See the `Updating version info' node of the Libtool manual before
 # changing this.
-libbddx_la_LDFLAGS = -no-undefined -version-info 0:0:0
+libbddx_la_LDFLAGS = -no-undefined -version-info 0:0:0 $(SYMBOLIC_LDFLAGS)
 libbddx_la_CPPFLAGS = $(BUDDY_FLAGS)
 libbddx_la_SOURCES = \
  bddio.c \
diff --git a/configure.ac b/configure.ac
index 580ce4a65..0d7d32642 100644
--- a/configure.ac
+++ b/configure.ac
@@ -118,6 +118,7 @@ LTDL_INIT([subproject convenience])
 link_all_deplibs=yes
 link_all_deplibs_CXX=yes
 
+AX_BSYMBOLIC
 
 AC_ARG_ENABLE([python],
               [AC_HELP_STRING([--disable-python],
diff --git a/iface/ltsmin/Makefile.am b/iface/ltsmin/Makefile.am
index 793afea84..d20011160 100644
--- a/iface/ltsmin/Makefile.am
+++ b/iface/ltsmin/Makefile.am
@@ -29,6 +29,7 @@ lib_LTLIBRARIES = libspotltsmin.la
 libspotltsmin_la_LIBADD = \
   $(top_builddir)/src/libspot.la \
   $(top_builddir)/ltdl/libltdlc.la -lpthread
+libspotltsmin_la_LDFLAGS = -no-undefined $(SYMBOLIC_LDFLAGS)
 libspotltsmin_la_SOURCES = ltsmin.cc
 
 noinst_PROGRAMS = modelcheck
diff --git a/m4/symbolic.m4 b/m4/symbolic.m4
new file mode 100644
index 000000000..238dc1a1f
--- /dev/null
+++ b/m4/symbolic.m4
@@ -0,0 +1,31 @@
+dnl This was addapted from a patch submitted written by H.J. Lu for GCC.
+dnl   https://gcc.gnu.org/ml/gcc/2007-01/msg00363.html
+dnl The -Bsymbolic-functions is no-longer part of the --help of ld, but
+dnl we can call ld -Bsymbolic-functions --help and it will choke if the
+dnl option is not supported.
+dnl Substitute SYMBOLIC_LDFLAGS with -Bsymbolic-functions for GNU linker
+dnl if it is supported.
+AC_DEFUN([AC_LIB_PROG_LD_GNU_SYMBOLIC],
+[AC_CACHE_CHECK([if the GNU linker ($LD) supports -Bsymbolic-functions],
+acl_cv_prog_gnu_ld_symbolic, [
+acl_cv_prog_gnu_ld_symbolic=no
+if test x"$with_gnu_ld" = x"yes"; then
+  if $LD -Bsymbolic-functions -Bsymbolic --help>/dev/null 2>&1 </dev/null; then
+    acl_cv_prog_gnu_ld_symbolic=yes
+  fi
+fi])
+if test x"$acl_cv_prog_gnu_ld_symbolic" = x"yes"; then
+  SYMBOLIC_LDFLAGS="-Wl,-Bsymbolic-functions -Wl,-Bsymbolic"
+else
+  SYMBOLIC_LDFLAGS=''
+fi
+AC_SUBST([SYMBOLIC_LDFLAGS])])
+
+AC_DEFUN([AX_BSYMBOLIC],
+[AC_ARG_ENABLE([Bsymbolic],
+   [AS_HELP_STRING([--disable-Bsymbolic],
+                   [disable linking with -Bsymbolic])],
+   [], [enable_Bsymbolic=yes])
+if test "$enable_Bsymbolic" != "no"; then
+  AC_LIB_PROG_LD_GNU_SYMBOLIC
+fi])
diff --git a/src/Makefile.am b/src/Makefile.am
index 18c2ae452..0e1fe606e 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -30,7 +30,7 @@ SUBDIRS = misc priv tl graph twa twaalgos ta taalgos kripke	\
 
 lib_LTLIBRARIES = libspot.la
 libspot_la_SOURCES =
-libspot_la_LDFLAGS = $(BUDDY_LDFLAGS) -no-undefined
+libspot_la_LDFLAGS = $(BUDDY_LDFLAGS) -no-undefined $(SYMBOLIC_LDFLAGS)
 libspot_la_LIBADD =  \
   kripke/libkripke.la \
   kripkeparse/libkripkeparse.la \
diff --git a/wrap/python/Makefile.am b/wrap/python/Makefile.am
index 1869561b4..327c33b11 100644
--- a/wrap/python/Makefile.am
+++ b/wrap/python/Makefile.am
@@ -36,7 +36,7 @@ MAINTAINERCLEANFILES = \
 ## spot
 
 _spot_impl_la_SOURCES = $(srcdir)/spot_impl_wrap.cxx
-_spot_impl_la_LDFLAGS = -avoid-version -module
+_spot_impl_la_LDFLAGS = -avoid-version -module -no-undefined $(SYMBOLIC_LDFLAGS)
 _spot_impl_la_LIBADD = $(top_builddir)/src/libspot.la
 
 $(srcdir)/spot_impl_wrap.cxx: $(srcdir)/spot_impl.i
@@ -49,7 +49,8 @@ $(srcdir)/spot_impl.py: $(srcdir)/spot_impl.i
 ## buddy
 
 _buddy_la_SOURCES = $(srcdir)/buddy_wrap.cxx
-_buddy_la_LDFLAGS = -avoid-version -module $(BUDDY_LDFLAGS)
+_buddy_la_LDFLAGS = -avoid-version -module $(BUDDY_LDFLAGS) \
+                    -no-undefined $(SYMBOLIC_LDFLAGS)
 
 $(srcdir)/buddy_wrap.cxx: $(srcdir)/buddy.i
 	$(SWIG) -c++ -python $(BUDDY_CPPFLAGS) $(srcdir)/buddy.i