llvm dev - Mar 2016 - clang triple and clang target

>
> I assume with target you mean the backend? Consider the x86 backend. It
> supports 32bit and 64bit mode, with the GNU x32 ABI in between. There
> are three different executable formats support (ELF, PE, MachO) with
> different constraints. Some platforms require 32bit alignment of the
> stack, others require 128bit alignment. The list goes on. The triple
> specifies
> the combination of target, OS and potentially file format and sub-ABI.
>
> Joerg
> _______________________________________________
> LLVM Developers mailing list
> llvm-dev at lists.llvm.org
> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>
Thanks for the response. I was trying to generate assembly which would use
vector instructions. I need to see how they look, whether it is ARM, Mips
or X86. However for some reason clang would generate an error saying that a
given target does not exist. Here is the command line I used:

clang -S test.c -o test.sse2.x86-64.s --target=x86-unknown-linux-eabi
-mfloat-abi=hard -mcpu=x86-64 -mfpu=SSE2 -fslp-vectorize-aggressive
-fslp-vectorize-aggressive -fslp-vectorize -fvectorize
-fno-lax-vector-conversions

Here is the response I got:
clang: warning: argument unused during compilation: '-mfloat-abi=hard'
clang: warning: argument unused during compilation: '-mcpu=x86-64'
clang: warning: argument unused during compilation: '-mfpu=SSE2'
error: unknown target triple 'x86-unknown-linux-eabi', please use
-triple
or -arch


I tried every possible combination of --target I could think of but nothing
worked. Would you mind helping me out?
Any help is appreciated.

-- 
Rail Shafigulin
Software Engineer
Esencia Technologies
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On 12 March 2016 at 11:51, Rail Shafigulin via llvm-dev
<llvm-dev at lists.llvm.org> wrote:
> I tried every possible combination of --target I could think of but nothing
> worked. Would you mind helping me out?
First, 64-bit x86 is "x86_64", and 32-bit is "i386" in the
triple. For
ARM you'd probably want "thumbv8" or "aarch64". Also,
"eabi" is only a
thing on ARM targets, try "gnu" for x86.

Cheers.

Tim.

> I need to see how they look, whether it is ARM, Mips or X86.
The Mips triples you're most likely to need are:

·         mips-linux-gnu – 32-bit big-endian on GNU/Linux

·         mipsel-linux-gnu – 32-bit little-endian on GNU/Linux

·         mips64-linux-gnu – 64-bit big-endian on GNU/Linux

·         mips64el-linux-gnu – 64-bit little-endian on GNU/Linux

I should mention that Mips has quite a few triple-related bugs but if you're
just looking at assembly the one you're most likely to encounter is that
mips-*/mipsel-* only work for 32-bit subtargets and mips64-*/mips64el-* only
work for 64-bit subtargets. If you don't match them up correctly then
you'll either get an assertion from the code generator or a crash. This
isn't supposed to be the case but there's been some unfortunate
misunderstandings about GNU triples and Clang triples (they're not quite the
same thing) that are difficult to resolve.

From: llvm-dev [mailto:llvm-dev-bounces at lists.llvm.org] On Behalf Of Rail
Shafigulin via llvm-dev
Sent: 12 March 2016 19:52
To: Joerg Sonnenberger; llvm-dev
Subject: Re: [llvm-dev] clang triple and clang target

I assume with target you mean the backend? Consider the x86 backend. It
supports 32bit and 64bit mode, with the GNU x32 ABI in between. There
are three different executable formats support (ELF, PE, MachO) with
different constraints. Some platforms require 32bit alignment of the
stack, others require 128bit alignment. The list goes on. The triple specifies
the combination of target, OS and potentially file format and sub-ABI.

Joerg
_______________________________________________
LLVM Developers mailing list
llvm-dev at lists.llvm.org<mailto:llvm-dev at lists.llvm.org>
http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev

Thanks for the response. I was trying to generate assembly which would use
vector instructions. I need to see how they look, whether it is ARM, Mips or
X86. However for some reason clang would generate an error saying that a given
target does not exist. Here is the command line I used:

clang -S test.c -o test.sse2.x86-64.s --target=x86-unknown-linux-eabi
-mfloat-abi=hard -mcpu=x86-64 -mfpu=SSE2 -fslp-vectorize-aggressive
-fslp-vectorize-aggressive -fslp-vectorize -fvectorize
-fno-lax-vector-conversions

Here is the response I got:
clang: warning: argument unused during compilation: '-mfloat-abi=hard'
clang: warning: argument unused during compilation: '-mcpu=x86-64'
clang: warning: argument unused during compilation: '-mfpu=SSE2'
error: unknown target triple 'x86-unknown-linux-eabi', please use
-triple or -arch


I tried every possible combination of --target I could think of but nothing
worked. Would you mind helping me out?
Any help is appreciated.

--
Rail Shafigulin
Software Engineer
Esencia Technologies
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On Mon, Mar 14, 2016 at 8:27 AM, Daniel Sanders <Daniel.Sanders at
imgtec.com>
wrote:
> > I need to see how they look, whether it is ARM, Mips or X86.
>
>
>
> The Mips triples you're most likely to need are:
>
> ·         mips-linux-gnu – 32-bit big-endian on GNU/Linux
>
> ·         mipsel-linux-gnu – 32-bit little-endian on GNU/Linux
>
> ·         mips64-linux-gnu – 64-bit big-endian on GNU/Linux
>
> ·         mips64el-linux-gnu – 64-bit little-endian on GNU/Linux
>
>
>
> I should mention that Mips has quite a few triple-related bugs but if
> you're just looking at assembly the one you're most likely to
encounter is
> that mips-*/mipsel-* only work for 32-bit subtargets and
> mips64-*/mips64el-* only work for 64-bit subtargets. If you don't match
> them up correctly then you'll either get an assertion from the code
> generator or a crash. This isn't supposed to be the case but
there's been
> some unfortunate misunderstandings about GNU triples and Clang triples
> (they're not quite the same thing) that are difficult to resolve.
>
>
>
Daniel,

Thanks for the response. I tried using the option you recommended but for
some reason I didn't see any vector instructions in the output. Can you
explain what am I doing wrong? Here is the command line I ran

clang -S test.c -o test.msa.mips.s --target=mips-pc-linux-gnu -mmsa -mfp64
-mfloat-abi=hard -mcpu=mips32 -fslp-vectorize-aggressive
 -fslp-vectorize-aggressive -fslp-vectorize -fvectorize
-fno-lax-vector-conversions -O3

I'm attaching test.c as well as test.msa.mips.s so you could see input as
well as output.

Any help is appreciated.
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On Sat, Mar 12, 2016 at 2:38 PM, Tim Northover <t.p.northover at
gmail.com>
wrote:
> On 12 March 2016 at 11:51, Rail Shafigulin via llvm-dev
> <llvm-dev at lists.llvm.org> wrote:
> > I tried every possible combination of --target I could think of but
> nothing
> > worked. Would you mind helping me out?
>
> First, 64-bit x86 is "x86_64", and 32-bit is "i386" in
the triple. For
> ARM you'd probably want "thumbv8" or "aarch64".
Also, "eabi" is only a
> thing on ARM targets, try "gnu" for x86.
>
> Cheers.
>
> Tim.
>
Hi Tim.

Thanks for the response. I tried the x86 suggestion but it didn't work.
Clearly I'm doing something wrong, but I don't know what exactly. I
would
really appreciate your help in this. Here is the command line I'm using

clang -S test.c -o test.sse2.x86_64.s --target=x86_64-pc-linux-gnu
-mfloat-abi=hard -mcpu=k8 -mfpu=SSE2 -fslp-vectorize-aggressive
-fslp-vectorize-aggressive -fslp-vectorize -fvectorize
-fno-lax-vector-conversions -O3

Here is the response that I get:

clang-3.5: warning: argument unused during compilation:
'-mfloat-abi=hard'
clang-3.5: warning: argument unused during compilation: '-mcpu=k8'
clang-3.5: warning: argument unused during compilation: '-mfpu=SSE2'
error: unable to create target: 'No available targets are compatible with
this triple, see -version for the available targets.'

clang --version command produces the following result:

clang version 3.5.0
Target: x86_64-unknown-linux-gnu
Thread model: posix

test.c is attached to this email.

So what am I doing wrong?

-- 
Rail Shafigulin
Software Engineer
Esencia Technologies
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