Patch for target library build failures when unable to link

[Joseph S. Myers]

Sometimes when building the compiler you cannot link while building
runtime libraries.  This is always the case on certain "generic"
targets such as powerpc-eabi (which by design do not link unless an
option such as -msim is passed); it may also arise in some compiler
bootstrap sequences.

Builds in such circumstances are currently broken in libssp and
libstdc++-v3.  The libssp breakage is P2 regression 25035; I'm not
aware of a PR for the libstdc++-v3 breakage, but it's also a
regression.

This patch fixes these build failures.  If you can't link then you
can't build shared libraries, so I think it is safe to disable symbol
versioning in this case.  The hardwired selection of available
functions for libssp is like that present for many targets in
libstdc++-v3/crossconfig.m4, and if required cases for specific
targets with mempcpy can be added in libssp.

This patch doesn't leave libssp perfect regarding cross-compilation,
since there remains an execution test for vsnprintf which should have
defaults depending on the target when cross-compiling, as many targets
will have working vsnprintf.  It does, however, fix the build failures
at least for powerpc-none-eabispe on which I tested (there may be
other libssp build failures in other configurations for other
reasons).

Tested by building a cross-compiler for powerpc-none-eabispe.  OK to
commit (to mainline and 4.1 branch)?

libssp:
2006-09-29  Joseph S. Myers  <joseph@codesourcery.com>

	PR other/25035
	* configure.ac (AC_EXEEXT): Remove.
	(GCC_NO_EXECUTABLES): Call.
	(ssp_use_symver): Default to no if unable to link.
	(AC_CHECK_FUNCS): Hardwire results if unable to link.
	* aclocal.m4, configure, Makefile.in: Regenerate.

libstdc++-v3:
2006-09-29  Joseph S. Myers  <joseph@codesourcery.com>

	* acinclude.m4 (enable_symvers): Default to no if unable to link.
	* configure: Regenerate.

Index: libstdc++-v3/acinclude.m4
===================================================================
--- libstdc++-v3/acinclude.m4	(revision 117274)
+++ libstdc++-v3/acinclude.m4	(working copy)
@@ -2158,7 +2158,7 @@
 
 # Turn a 'yes' into a suitable default.
 if test x$enable_symvers = xyes ; then
-  if test $enable_shared = no || test "x$LD" = x ; then
+  if test $enable_shared = no || test "x$LD" = x || test x$gcc_no_link = xyes; then
     enable_symvers=no
   else
     if test $with_gnu_ld = yes ; then
Index: libssp/configure.ac
===================================================================
--- libssp/configure.ac	(revision 117274)
+++ libssp/configure.ac	(working copy)
@@ -22,8 +22,9 @@
 AC_MSG_RESULT($version_specific_libs)
 
 AM_MAINTAINER_MODE
-AC_EXEEXT
 
+GCC_NO_EXECUTABLES
+
 AM_ENABLE_MULTILIB(, ..)
 
 target_alias=${target_alias-$host_alias}
@@ -78,14 +79,27 @@
 EOF
 save_LDFLAGS="$LDFLAGS"
 LDFLAGS="$LDFLAGS -fPIC -shared -Wl,--version-script,./conftest.map"
-AC_TRY_LINK([int foo;],[],[ssp_use_symver=yes],[ssp_use_symver=no])
+if test x$gcc_no_link = xyes; then
+  # If we cannot link, we cannot build shared libraries, so do not use
+  # symbol versioning.
+  ssp_use_symver=no
+else
+  AC_TRY_LINK([int foo;],[],[ssp_use_symver=yes],[ssp_use_symver=no])
+fi
 LDFLAGS="$save_LDFLAGS"
 AC_MSG_RESULT($ssp_use_symver)
 AM_CONDITIONAL(LIBSSP_USE_SYMVER, [test "x$ssp_use_symver" = xyes])
 
 AC_CHECK_HEADERS(alloca.h paths.h syslog.h string.h unistd.h fcntl.h stdio.h limits.h)
 
-AC_CHECK_FUNCS(mempcpy strncpy strncat)
+if test x$gcc_no_link = xyes; then
+  # Presume the ISO C functions are available; add target-specific
+  # configuration here if required.
+  AC_DEFINE(HAVE_STRNCPY)
+  AC_DEFINE(HAVE_STRNCAT)
+else
+  AC_CHECK_FUNCS(mempcpy strncpy strncat)
+fi
 
 AC_MSG_CHECKING([whether vsnprintf is usable])
 AC_RUN_IFELSE(AC_LANG_PROGRAM([


-- 
Joseph S. Myers
joseph@codesourcery.com