Ensure the linker supports @unwind sections in libffi. From Mozilla bug 756740.

https://bugzilla.mozilla.org/show_bug.cgi?id=778414

Also tracked as issue #42.
https://github.com/atgreen/libffi/issues/42

diff --git a/ChangeLog b/ChangeLog
index 03bfdff..f24e251 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+2014-03-10  Landry Breuil <landry@openbsd.org>
+
+       * configure.ac: Ensure the linker supports @unwind sections in libffi.
+
 2014-03-01  Anthony Green  <green@moxielogic.com>
 
        * Makefile.am (EXTRA_DIST): Replace old scripts with

diff --git a/configure.ac b/configure.ac
index 4dd919d..90a11f6 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -215,7 +215,7 @@ case "$host" in
   mips-sgi-irix5.* | mips-sgi-irix6.* | mips*-*-rtems*)
        TARGET=MIPS; TARGETDIR=mips
        ;;
-  mips*-*-linux* | mips*-*-openbsd*)
+  mips*-*linux* | mips*-*-openbsd*)
        # Support 128-bit long double for NewABI.
        HAVE_LONG_DOUBLE='defined(__mips64)'
        TARGET=MIPS; TARGETDIR=mips
@@ -460,12 +460,28 @@ AM_CONDITIONAL(FFI_EXEC_TRAMPOLINE_TABLE, test x$FFI_EXEC_TRAMPOLINE_TABLE = x1)
 AC_SUBST(FFI_EXEC_TRAMPOLINE_TABLE)
 
 if test x$TARGET = xX86_64; then
-    AC_CACHE_CHECK([assembler supports unwind section type],
+    AC_CACHE_CHECK([toolchain supports unwind section type],
        libffi_cv_as_x86_64_unwind_section_type, [
-       libffi_cv_as_x86_64_unwind_section_type=yes
-       echo '.section .eh_frame,"a",@unwind' > conftest.s
-       if $CC $CFLAGS -c conftest.s 2>&1 | grep -i warning > /dev/null; then
-           libffi_cv_as_x86_64_unwind_section_type=no
+        cat  > conftest1.s << EOF
+.text
+.globl foo
+foo:
+jmp bar
+.section .eh_frame,"a",@unwind
+bar:
+EOF
+
+        cat > conftest2.c  << EOF
+extern void foo();
+int main(){foo();}
+EOF
+
+       libffi_cv_as_x86_64_unwind_section_type=no
+       # we ensure that we can compile _and_ link an assembly file containing an @unwind section
+       # since the compiler can support it and not the linker (ie old binutils)
+       if $CC -Wa,--fatal-warnings $CFLAGS -c conftest1.s > /dev/null 2>&1 && \
+           $CC conftest2.c conftest1.o > /dev/null 2>&1 ; then
+           libffi_cv_as_x86_64_unwind_section_type=yes
        fi
        ])
     if test "x$libffi_cv_as_x86_64_unwind_section_type" = xyes; then