On MIPS clang default to different arch than GNU

On MIPS clang default to different arch than GNU

[Andrei Borzenkov]

clang -cc1 version 3.8.0 based upon LLVM 3.8.0svn default target x86_64-unknown-linux-gnu
ignoring nonexistent directory "/include"
#include "..." search starts here:
#include <...> search starts here:
 /usr/local/include
 /home/bor/build/clang/bin/../lib/clang/3.8.0/include
 /usr/include
End of search list.
 "/usr/bin/mips-suse-linux-as" -march mips32r2 -mabi 32 -call_nonpic -EB -msoft-float -KPIC -o conftest /tmp/foo-3da0d2.s
bor@opensuse:~/src/llvm/tools/clang> file conftest 
conftest: ELF 32-bit MSB relocatable, MIPS, MIPS32 rel2 version 1 (SYSV), not stripped

While for the same file GAS creates

bor@opensuse:~/build/grub> mips-suse-linux-as -v asm-tests/mips.S 
GNU assembler version 2.24.0 (mips-suse-linux) using BFD version (GNU Binutils; openSUSE 13.2) 2.24.0.20140403-6.1
bor@opensuse:~/build/grub> file a.out 
a.out: ELF 32-bit MSB relocatable, MIPS, MIPS-I version 1 (SYSV), not stripped
bor@opensuse:~/build/grub> 

(using -integrated-as does not change it - arch is still the same).

Not sure if it matters.

Re: On MIPS clang default to different arch than GNU

[Vladimir 'φ-coder/phcoder' Serbinenko]

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On 19.07.2015 09:33, Andrei Borzenkov wrote:
> clang -cc1 version 3.8.0 based upon LLVM 3.8.0svn default target x86_64-unknown-linux-gnu
> ignoring nonexistent directory "/include"
> #include "..." search starts here:
> #include <...> search starts here:
>  /usr/local/include
>  /home/bor/build/clang/bin/../lib/clang/3.8.0/include
>  /usr/include
> End of search list.
>  "/usr/bin/mips-suse-linux-as" -march mips32r2 -mabi 32 -call_nonpic -EB -msoft-float -KPIC -o conftest /tmp/foo-3da0d2.s
> bor@opensuse:~/src/llvm/tools/clang> file conftest 
> conftest: ELF 32-bit MSB relocatable, MIPS, MIPS32 rel2 version 1 (SYSV), not stripped
> 
> While for the same file GAS creates
> 
> bor@opensuse:~/build/grub> mips-suse-linux-as -v asm-tests/mips.S 
> GNU assembler version 2.24.0 (mips-suse-linux) using BFD version (GNU Binutils; openSUSE 13.2) 2.24.0.20140403-6.1
> bor@opensuse:~/build/grub> file a.out 
> a.out: ELF 32-bit MSB relocatable, MIPS, MIPS-I version 1 (SYSV), not stripped
> bor@opensuse:~/build/grub> 
> 
> (using -integrated-as does not change it - arch is still the same).
> 
> Not sure if it matters.
> 
> 
I think it doesn't. It's just on the level of flags. I don't think that
it really generates any non-mips1 instructions unless specifically asked
for. Just it fails to reflect this in flags in resulting binary.
Unlike in the case of x86, on mips there is no need to enable
instruction subsets, so if compiler generates instructions not supported
by target, then it's misconfigured and it's likely bigger problem than
just GRUB.
> _______________________________________________
> Grub-devel mailing list
> Grub-devel@gnu.org
> https://lists.gnu.org/mailman/listinfo/grub-devel
> 



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Re: On MIPS clang default to different arch than GNU

[Andrei Borzenkov]

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В Wed, 22 Jul 2015 02:05:29 +0200
Vladimir 'φ-coder/phcoder' Serbinenko <phcoder@gmail.com> пишет:

> On 19.07.2015 09:33, Andrei Borzenkov wrote:
> > clang -cc1 version 3.8.0 based upon LLVM 3.8.0svn default target x86_64-unknown-linux-gnu
> > ignoring nonexistent directory "/include"
> > #include "..." search starts here:
> > #include <...> search starts here:
> >  /usr/local/include
> >  /home/bor/build/clang/bin/../lib/clang/3.8.0/include
> >  /usr/include
> > End of search list.
> >  "/usr/bin/mips-suse-linux-as" -march mips32r2 -mabi 32 -call_nonpic -EB -msoft-float -KPIC -o conftest /tmp/foo-3da0d2.s
> > bor@opensuse:~/src/llvm/tools/clang> file conftest 
> > conftest: ELF 32-bit MSB relocatable, MIPS, MIPS32 rel2 version 1 (SYSV), not stripped
> > 
> > While for the same file GAS creates
> > 
> > bor@opensuse:~/build/grub> mips-suse-linux-as -v asm-tests/mips.S 
> > GNU assembler version 2.24.0 (mips-suse-linux) using BFD version (GNU Binutils; openSUSE 13.2) 2.24.0.20140403-6.1
> > bor@opensuse:~/build/grub> file a.out 
> > a.out: ELF 32-bit MSB relocatable, MIPS, MIPS-I version 1 (SYSV), not stripped
> > bor@opensuse:~/build/grub> 
> > 
> > (using -integrated-as does not change it - arch is still the same).
> > 
> > Not sure if it matters.
> > 
> > 
> I think it doesn't. It's just on the level of flags. I don't think that
> it really generates any non-mips1 instructions unless specifically asked
> for.

Does not -march mips32r2 does it?


>      Just it fails to reflect this in flags in resulting binary.
> Unlike in the case of x86, on mips there is no need to enable
> instruction subsets, so if compiler generates instructions not supported
> by target, then it's misconfigured and it's likely bigger problem than
> just GRUB.
> > _______________________________________________
> > Grub-devel mailing list
> > Grub-devel@gnu.org
> > https://lists.gnu.org/mailman/listinfo/grub-devel
> > 
> 
> 


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