Port libvtv to Solaris

Tue Nov 24 10:24:00 GMT 2015

Rainer Orth <ro@CeBiTec.Uni-Bielefeld.DE> writes:

> Now that init priority support on Solaris is on mainline, porting libvtv
> proved to be relatively easy, though it discovered a couple of quirks on
> a non-gld non-x86 platform.

This patch has now remained unreviewed for a week.  With both Jeff and
Richi fine with it going into mainline even this late, it would be nice
if Caroline could find the time to review it.

Linux/x86_64 testing found one minor issue, explained below.  I'm
attaching the updated patch.

> A considerable part of the patch lives in Solaris-specific files and
> thus doesn't need approval, though some changes require explanation:
>
> * In gcc.c (LINK_COMMAND_SPEC), VTABLE_VERIFICATION_SPEC was before
>   %{L*}.  The spec includes -lvtv.  Solaris ld, other than GNU ld, heeds
>   the relative order of -L and -l switches, so the libvtv testcases
>   wouldn't link manually, but did inside a testsuite run where
>   LD_LIBRARY_PATH points ld at the correct directory.
>
> * Solaris/SPARC uses an 8 kB page size, so a couple of cases where uses
>   of VTV_PAGE_SIZE had been replaced with hardcoded values of 4096 had
>   to be reverted.
>
> * Inside libgcc, the vtv_*.c files are compiled with
>   -finhibit-size-directive, whereas in libvtv that flag is absent.  This
>   caused all testcases to fail due to a linker warning:
>
> FAIL: libvtv.cc/bb_tests.cc -O0 -fvtable-verify=std (test for excess errors)
> Excess errors:
> ld: warning: symbol '_vtable_map_vars_end' has differing sizes:
>         (file /var/gcc/gcc-6.0.0-20151111/12-gcc-vtv/sparc-sun-solaris2.12/./libvtv/.libs/libvtv.so value=0x1000; file /var/gcc/gcc-6.0.0-20151111/12-gcc-vtv/gcc/vtv_end.o value=0x0);
>         /var/gcc/gcc-6.0.0-20151111/12-gcc-vtv/gcc/vtv_end.o definition taken
>
> * Like Cygwin, Solaris has no obstack functions in libc, so I'm now
>   using a common conditional for that.
>
> * libvtv requires constructor priority support and dl_iterate_phdr.  The
>   former needs either a recent (Solaris 12 only so far) ld or gld, the
>   latter came in Solaris 11 only.
>
> * Unlike glibc systems, Solaris has no __fortify_fail in libc; some of
>   this can probably provided using libbacktrace, which I haven't yet
>   done.
>
> * It also lacks program_invocation_name, but the functionality can be
>   provided via getexecname() instead.
>
> * On Solaris 12/SPARC with Solaris as, the .vtable_map_vars section
>   wouldn't be pagesize aligned (I'm still looking how to fix this; it
>   works out of the box for .bss), so the section length calclated in
>   read_section_offset_and_length would be negative, leading to all sorts
>   of havoc.  For the moment, I'm using gas instead to avoid this.
>
> * The patch also fixes a number of typos noticed during testing.
>
> With those changes, I get almost clean libvtv test results on
> i386-pc-solaris2.12 (as/ld and gas/gld) and sparc-sun-solaris2.12
> (gas/ld):
>
> * i386-pc-solaris2.12:
>
> 		=== libvtv tests ===
>
>
> Running target unix
>
> 		=== libvtv Summary for unix ===
>
> # of expected passes		176
>
> Running target unix/-m64
> WARNING: program timed out.
> FAIL: libvtv.mt.cc/register_set_pair_inserts_mt.cc -O0 -fvtable-verify=std -lpthread execution test
> WARNING: program timed out.
> FAIL: libvtv.mt.cc/register_set_pair_inserts_mt.cc -O2 -fvtable-verify=std -lpthread execution test
>
> 		=== libvtv Summary for unix/-m64 ===
>
> # of expected passes		174
> # of unexpected failures	2
>
> 		=== libvtv Summary ===
>
> # of expected passes		350
> # of unexpected failures	2
>
> * sparc-sun-solaris2.12:
>
> 		=== libvtv tests ===
>
>
> Running target unix
> WARNING: program timed out.
> FAIL: libvtv.mt.cc/register_set_pair_inserts_mt.cc -O0 -fvtable-verify=std -lpthread execution test
> WARNING: program timed out.
> FAIL: libvtv.mt.cc/register_set_pair_mt.cc -O0 -fvtable-verify=std -lpthread execution test
> WARNING: program timed out.
> FAIL: libvtv.mt.cc/register_set_pair_inserts_mt.cc -O2 -fvtable-verify=std -lpthread execution test
> WARNING: program timed out.
> FAIL: libvtv.mt.cc/register_set_pair_mt.cc -O2 -fvtable-verify=std -lpthread execution test
>
> 		=== libvtv Summary for unix ===
>
> # of expected passes		172
> # of unexpected failures	4
>
> Running target unix/-m64
> WARNING: program timed out.
> FAIL: libvtv.mt.cc/register_set_pair_inserts_mt.cc -O0 -fvtable-verify=std -lpthread execution test
> WARNING: program timed out.
> FAIL: libvtv.mt.cc/register_set_pair_mt.cc -O0 -fvtable-verify=std -lpthread execution test
> WARNING: program timed out.
> FAIL: libvtv.mt.cc/register_set_pair_inserts_mt.cc -O2 -fvtable-verify=std -lpthread execution test
> WARNING: program timed out.
> FAIL: libvtv.mt.cc/register_set_pair_mt.cc -O2 -fvtable-verify=std -lpthread execution test
>
> 		=== libvtv Summary for unix/-m64 ===
>
> # of expected passes		172
> # of unexpected failures	4
>
> 		=== libvtv Summary ===
>
> # of expected passes		344
> # of unexpected failures	8
>
> I'm still investigating what causes those timeouts, it seems to be a
> scalability issue in libc.
>
> While I realize that we are past stage1, maybe the fact that this patch
> is for an off-by-default feature and well localized still could allow it
> into mainline at this point?

On x86_64-pc-linux-gnu, initial testing found all libvtv testcases
failing initially like this:

FAIL: libvtv.cc/bb_tests.cc -O0 -fvtable-verify=std (test for excess errors)
Excess errors:
vtv_end.c:(.text.startup+0x0): multiple definition of `__VLTprotect'
/var/gcc/gcc-6.0.0-20151111/3.19.8-gcc-gas-gld-vtv/x86_64-pc-linux-gnu/./libvtv/.libs/libvtv.a(vtv_end.o):/var/gcc/gcc-6.0.0-20151111/3.19.8-gcc-gas-gld-vtv/x86_64-pc-linux-gnu/libvtv/vtv_end.c:59: first defined here

It turned out that while the libvtv.so.0 and libvtv.so symlinks were
built, libvtv.so.0.0.0 proper was not.  I'd overlooked this aucotonf
warning:

ro@lokon 1503 > autoconf
configure.ac:109: warning: AC_COMPILE_IFELSE was called before AC_USE_SYSTEM_EXTENSIONS
/vol/src/gnu/autoconf/autoconf-2.64/lib/autoconf/specific.m4:332: AC_GNU_SOURCE is expanded from...
configure.ac:109: the top level

As expected, adding the macro to configure.ac fixed both the warning and
the libvtv.so.0.0.0 build, so Linux/x86_64 results are all fine again.

Thanks.

	Rainer

2015-08-20  Rainer Orth  <ro@CeBiTec.Uni-Bielefeld.DE>

	libstdc++-v3:
	* acinclude.m4 (GLIBCXX_ENABLE_VTABLE_VERIFY) <solaris2*>: Use
	-Wl,-R in VTV_CXXLINKFLAGS.
	* configure: Regenerate.

	* testsuite/18_support/bad_exception/23591_thread-1.c: Use
	-fvtable-verify=none on Solaris 12+.

	libgcc:
	* Makefile.in (VTV_CFLAGS): New variable.
	(vtv_start$(objext), vtv_end$(objext), vtv_end$(objext))
	(vtv_start_preinit$(objext), vtv_end_preinit$(objext)): Use it.
	* config.host (*-*-solaris2*): Add t-crtstuff-pic to tmake_file.
	Add vtv_start.o, vtv_end.o, vtv_start_preinit.o, vtv_end_preinit.o
	to extra_parts if $enable_vtable_verify = yes.

	libvtv:
	* configure.tgt (*-*-solaris2.[1-9]*): Declare supported.
	* configure.ac: Call AC_USE_SYSTEM_EXTENSIONS.
	<*-*-solaris2*>: Check for init priority support.
	Check for getexecname, __fortify_fail, _obstack_begin.
	(VTV_NO_OBSTACK): New conditional.
	* configure: Regenerate.
	* Makefile.am [VTV_NO_OBSTACK] (obstack.c): Use new condition.
	* Makefile.in: Regenerate.

	* vtv_rts.cc [HAVE_GETEXECNAME] (program_invocation_name): New
	variable.
	(read_section_offset_and_length) [HAVE_GETEXECNAME]: Set it.
	(dl_iterate_phdr_callback) [HAVE_GETEXECNAME]: Set it.

	(__fortify_fail): Wrap in HAVE___FORTIFY_FAIL
	[!HAVE___FORTIFY_FAIL]: Provide non-Cygwin implementation.

	(read_section_offset_and_length): Assert sh_size >= VTV_PAGE_SIZE.
	(iterate_modules): Fix typo.
	Use VTV_PAGE_SIZE.
	(dl_iterate_phdr_callback): Fix typo.
	Use VTV_PAGE_SIZE.
	(__VLTChangePermission): Fix typos.

	include:
	* vtv-change-permission.h (VTV_PAGE_SIZE) [__sun__ && __svr4__ &&
	__sparc__]: Define.

	gcc:
	* config/sol2.h (SUPPORTS_INIT_PRIORITY): Move up.
	(STARTFILE_VTV_SPEC, ENDFILE_VTV_SPEC): Define.
	(STARTFILE_SPEC): Use %(startfile_vtv).
	(ENDFILE_SPEC): Use %(endfile_vtv).
	(SUBTARGET_EXTRA_SPECS): Handle STARTFILE_VTV_SPEC,
	ENDFILE_VTV_SPEC.

	* gcc.c (LINK_COMMAND_SPEC): Move VTABLE_VERIFICATION_SPEC after %{L*}.

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Rainer Orth, Center for Biotechnology, Bielefeld University