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Date:      Sun, 27 Jul 2014 14:39:27 -0500
From:      Stacey Son <sson@FreeBSD.org>
To:        David Chisnall <theraven@FreeBSD.org>
Cc:        freebsd-mips@FreeBSD.org
Subject:   Re: mips64 ld GOT problem
Message-ID:  <37D1F27C-B595-43AA-A0F8-6B48AE4D7C69@FreeBSD.org>
In-Reply-To: <2021F70B-2AA4-412C-8D1B-A8D38A3E031C@FreeBSD.org>
References:  <77F1DDA2-A4E5-4D64-AA43-F8CBC55249C4@me.com> <48935A3D-0387-42F1-ACF0-14EB7D8F9A06@bsdimp.com> <C7869A0A-8CE6-4764-9AFD-A49C93E680C1@FreeBSD.org> <2021F70B-2AA4-412C-8D1B-A8D38A3E031C@FreeBSD.org>

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Hi David:

Compiling with the cmake option "-DBUILD_SHARED_LIBS=3DTrue" does get it =
pass linking 'opt' but it later fails later on...

[ 73%] Building CXX object =
tools/clang/lib/AST/CMakeFiles/clangAST.dir/VTTBuilder.cpp.o
Linking CXX shared library ../../../../lib/libclangAST.so
[...]
/home/sson/llvm/tools/clang/lib/AST/ASTContext.cpp:(.text+0x710): =
relocation truncated to fit: R_MIPS_CALL16 against `bool =
llvm::isa<clang::ObjCPropertyDecl, clang::Decl const*>(clang::Decl =
const* const&)'
[...]
/home/sson/llvm/tools/clang/lib/AST/ASTContext.cpp:(.text+0x5a98): =
additional relocation overflows omitted from the output
clang-3.5: error: linker command failed with exit code 1 (use -v to see =
invocation)
*** Error code 1

As for enabling optimization, when I use "-DCMAKE_BUILD_TYPE=3DRelease" =
or "-DCMAKE_BUILD_TYPE=3DMinSizeRel" with the cmake I get an =
"EmitRawText called on an MCStreamer that doesn't support it,  something =
must not be fully mc'ized" abort.   Only "-DCMAKE_BUILD_TYPE=3DDebug" or =
"-DCMAKE_BUILD_TYPE=3DNone" seems to work.   Maybe I am not enabling the =
optimization correctly?

I have been able to get ld from binutils 2.24 to mostly work.  It will =
link binaries with "-static" but dynamic binaries are still a problem.  =
It seems the default ldscript is not quite right or something.

-stacey.

On Jul 26, 2014, at 6:46 AM, David Chisnall <theraven@FreeBSD.org> =
wrote:

> The only way that I've ever got llvm to compile for MIPS has been by =
enabling shared libraries, enabling optimisation, and disabling debug =
info.  This gave each shared lib a small enough GOT for our binutils =
linker to work.
>=20
> Newer binutils supports multi-GOT (GOT is split and different GOTs are =
installed by some calls) and large-GOT (GOT accesses use register =
offsets) modes.
>=20
> David
>=20
> On 25 Jul 2014, at 23:27, Stacey Son <sson@FreeBSD.org> wrote:
>=20
>>=20
>> Hi Warner...
>>=20
>> On Jul 25, 2014, at 11:26 AM, Warner Losh <imp@bsdimp.com> wrote:
>>=20
>>>=20
>>> On Jul 25, 2014, at 9:24 AM, Stacey Son <sson@me.com> wrote:
>>>=20
>>>> Hi all:
>>>>=20
>>>> I have been trying to bootstrap clang/llvm 3.5 for mips64 (i.e. =
cross build clang/llvm 3.5 for mips64 using clang/llvm 3.5) but run into =
the following linker problem (see below) in about the midway point as it =
is trying to link 'opt'.   The assertions that fail are the following:
>>>>=20
>>>> BFD 2.17.50 [FreeBSD] 2007-07-03 assertion fail =
/usr/home/sson/freebsd/gnu/usr.bin/binutils/libbfd/../../../../contrib/bin=
utils/bfd/elfxx-mips.c:7455
>>>>=20
>>>>               BFD_ASSERT (g->assigned_gotno - g->local_gotno
>>>>                           <=3D g->global_gotno);
>>>>=20
>>>> BFD 2.17.50 [FreeBSD] 2007-07-03 assertion fail =
/usr/home/sson/freebsd/gnu/usr.bin/binutils/libbfd/../../../../contrib/bin=
utils/bfd/elfxx-mips.c:2767
>>>>=20
>>>> /* There should have been enough room in the symbol table to
>>>>  accommodate both the GOT and non-GOT symbols.  */
>>>> BFD_ASSERT (hsd.max_non_got_dynindx <=3D hsd.min_got_dynindx);
>>>>=20
>>>> BFD 2.17.50 [FreeBSD] 2007-07-03 assertion fail =
/usr/home/sson/freebsd/gnu/usr.bin/binutils/libbfd/../../../../contrib/bin=
utils/bfd/elfxx-mips.c:10282
>>>>=20
>>>>   /* Make sure we didn't grow the global .got region.  */
>>>>   dynobj =3D elf_hash_table (info)->dynobj;
>>>>   got =3D mips_elf_got_section (dynobj, FALSE);
>>>>   g =3D mips_elf_section_data (got)->u.got_info;
>>>>=20
>>>>   if (g->global_gotsym !=3D NULL)
>>>>     BFD_ASSERT ((elf_hash_table (info)->dynsymcount
>>>>                  - g->global_gotsym->dynindx)
>>>>                 <=3D g->global_gotno);
>>>>=20
>>>> Does anyone have an idea for a work around or fix?
>>>=20
>>> Silly question: does using the latest binutils fix this problem?
>>=20
>> Is there a stable port of the latest binutils to mips?  Does someone =
have some patches?  I did tried TheRaven's port of the 2.18 binutils but =
it seemed that 'ld' wasn't very happy.  It didn't like any of the object =
files I offered it.
>>=20
>>> Failing that, perhaps we need to specify a larger GOT region that we =
do today?  IIRC, that=92s specified with -g on the linker line, Try =
adding =93-G0=94. I have a vague recollection we always used to do this, =
but moved it to be a default (or maybe other systems have the default =
and we still need to add it). It doesn=92t look like it is being added =
from the output that you=92ve posted. IIRC, it has to be specified on =
all the compiler invocations as well.
>>=20
>> Reading the man page implies  -Gvalue/--gpsize=3Dvalue is only for =
ECOFF binaries.  I tried it anyway and it didn't seem to help.
>>=20
>> -stacey.
>=20




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