llvm dev - Jul 2012 - [LLVMdev] how to change a compiler from a host to a target in Clang's assembler and linker

Hi,

I would like to ask you how to use Clang in cross-compile environment. My
environment is as follows:
------
HOST: 32-bit Fedora 16 with Intel Core i7
      gcc/g++ compiler available
TARGET: 32-bit mips-typed linux
      gnu gcc/g++ for 32-bit mips-typed linux available
------
       
As Clang's option is "-c" in use, my programs are compiled and
linked under a host machine's environment (in my case, 32-bit Fedora 16 is a
host OS with Intel Core i7).

In order to compile and link them under a target's environment (in my case,
mips-typed linux gcc/g++ can work), in Clang’s "Assembler" and
"Linker" processes, a compiler on a host should be changed to one on a
target. Still now, I cannot find out a file to set a compiler for
"Assembler" and "Linker" in Clang. Please advise me how to
change a compiler from a host one to a target one.

Regards,
------------
Noriko Etani

Konbanwa, Etani san,

It might be clang driver issue. Move to cfe-dev.

2012/7/4 ETANI NORIKO <noriko-e at
fc.ritsumei.ac.jp>:
> I would like to ask you how to use Clang in cross-compile environment. My
environment is as follows:
> ------
> HOST: 32-bit Fedora 16 with Intel Core i7
>       gcc/g++ compiler available
> TARGET: 32-bit mips-typed linux
>       gnu gcc/g++ for 32-bit mips-typed linux available
> ------
* What do you specify as -target? (eg. clag -c -target i686-pc-mingw32)

* Which toolchain have you installed and what is the prefix of it?
AFAIU, GNU binutils for the target would be essential.
(eg. /usr/bin/i686-pc-mingw32-ld)
> As Clang's option is "-c" in use, my programs are compiled
and linked under a host machine's environment (in my case, 32-bit Fedora 16
is a host OS with Intel Core i7).
>
> In order to compile and link them under a target's environment (in my
case, mips-typed linux gcc/g++ can work), in Clang’s "Assembler" and
"Linker" processes, a compiler on a host should be changed to one on a
target. Still now, I cannot find out a file to set a compiler for
"Assembler" and "Linker" in Clang. Please advise me how to
change a compiler from a host one to a target one.
* Have you tried "clang -c -integrated-as"?

To Mips guys: Do you think Mips MC assembler would work?

FYI, workaround.
clang -S hogehoge.c
target-gcc -c hogehoge.s
target-gcc -o fugafuga hogehoge.o ...
(I don't know how mips-clang would be mature)

...Takumi (中村)

I think it is a driver issue too. The files should be in clang/lib/driver, but I
am not very familiar with the code in the files. Perhaps Simon can answer your
questions.

llvm's test suite is run against clang/llvm nightly with direct object
emission, so I believe clang's integrated assembler should work fine.

$ clang foo.c -c -O3   -integrated-as   -target mipsel-unknown-linux 
-ccc-clang-archs mipsel

________________________________________
From: NAKAMURA Takumi [geek4civic at gmail.com]
Sent: Friday, July 06, 2012 8:12 AM
To: noriko-e at fc.ritsumei.ac.jp
Cc: llvmdev; cfe-dev; Hatanaka, Akira; Kotler, Reed
Subject: Re: [LLVMdev] how to change a compiler from a host to a target in
Clang's assembler and linker

Konbanwa, Etani san,

It might be clang driver issue. Move to cfe-dev.

2012/7/4 ETANI NORIKO <noriko-e at
fc.ritsumei.ac.jp>:
> I would like to ask you how to use Clang in cross-compile environment. My
environment is as follows:
> ------
> HOST: 32-bit Fedora 16 with Intel Core i7
>       gcc/g++ compiler available
> TARGET: 32-bit mips-typed linux
>       gnu gcc/g++ for 32-bit mips-typed linux available
> ------
* What do you specify as -target? (eg. clag -c -target i686-pc-mingw32)

* Which toolchain have you installed and what is the prefix of it?
AFAIU, GNU binutils for the target would be essential.
(eg. /usr/bin/i686-pc-mingw32-ld)
> As Clang's option is "-c" in use, my programs are compiled
and linked under a host machine's environment (in my case, 32-bit Fedora 16
is a host OS with Intel Core i7).
>
> In order to compile and link them under a target's environment (in my
case, mips-typed linux gcc/g++ can work), in Clang’s "Assembler" and
"Linker" processes, a compiler on a host should be changed to one on a
target. Still now, I cannot find out a file to set a compiler for
"Assembler" and "Linker" in Clang. Please advise me how to
change a compiler from a host one to a target one.
* Have you tried "clang -c -integrated-as"?

To Mips guys: Do you think Mips MC assembler would work?

FYI, workaround.
clang -S hogehoge.c
target-gcc -c hogehoge.s
target-gcc -o fugafuga hogehoge.o ...
(I don't know how mips-clang would be mature)

...Takumi (中村)

Hi,

On Wed, Jul 4, 2012 at 9:21 AM, ETANI NORIKO <noriko-e at
fc.ritsumei.ac.jp> wrote:
> Please advise me how to change a compiler from a host one to a target one.
Suppose MIPS toolchain is installed in the $MIPS folder (i.e.
mips-linux-gnu-gcc is in the $MIPS/bin folder). Note, if you want to
generate little-endian code and/or 64-bit code, you have to create the
following links in the $MIPS/bin folder:
* Little-endian 32-bit
    ln -s mips-linux-gnu-ld mipsel-linux-gnu-ld
    ln -s mips-linux-gnu-as mipsel-linux-gnu-as
* Little-endian 64-bit
    ln -s mips-linux-gnu-ld mips64el-linux-gnu-ld
    ln -s mips-linux-gnu-as mips64el-linux-gnu-as
* Big-endian 64-bit
    ln -s mips-linux-gnu-ld mips64-linux-gnu-ld
    ln -s mips-linux-gnu-as mips64-linux-gnu-as

If you use integrated assembler (turned on by -integrated-as option)
you can skip mips-linux-gnu-as links creation.

Exact command line options depends on used toolchain. Examples below
work for Mentor Graphics Toolchain version 2011.09-75
(https://sourcery.mentor.com/GNUToolchain/subscription3130?lite=MIPS).

* Little-endian 32-bit
$ clang -target mipsel-linux-gnu main.c -static \
    --sysroot $MIPS/mips-linux-gnu/libc/el \
    -I$MIPS/mips-linux-gnu/libc/usr/include \
    -B$MIPS/lib/gcc/mips-linux-gnu/4.5.2/el \
    -L$MIPS/lib/gcc/mips-linux-gnu/4.5.2/el \
    -integrated-as

* Big-endian 32-bit
$ clang -target mips-linux-gnu main.c -static \
    --sysroot $MIPS/mips-linux-gnu/libc \
    -I$MIPS/mips-linux-gnu/libc/usr/include \
    -B$MIPS/lib/gcc/mips-linux-gnu/4.5.2 \
    -L$MIPS/lib/gcc/mips-linux-gnu/4.5.2 \
    -integrated-as

* Little-endian 64-bit
$ clang -target mips64el-linux-gnu main.c -static \
    --sysroot $MIPS/mips-linux-gnu/libc/el \
    -I$MIPS/mips-linux-gnu/libc/usr/include \
    -B$MIPS/lib/gcc/mips-linux-gnu/4.5.2/el/64 \
    -L$MIPS/lib/gcc/mips-linux-gnu/4.5.2/el/64

* Big-endian 64-bit
$ clang -target mips64-linux-gnu main.c -static \
    --sysroot $MIPS/mips-linux-gnu/libc \
    -I$MIPS/mips-linux-gnu/libc/usr/include \
    -B$MIPS/lib/gcc/mips-linux-gnu/4.5.2/64 \
    -L$MIPS/lib/gcc/mips-linux-gnu/4.5.2/64

If that does not work for you, could you please provide more information:
1. What command line options do you use?
2. What toolchain do you use and where is it installed?
3. What errors do you get?

--
Simon

On Fri, Jul 06, 2012 at 10:40:58PM +0400, Simon Atanasyan
wrote:
> * Little-endian 32-bit
> $ clang -target mipsel-linux-gnu main.c -static \
>     --sysroot $MIPS/mips-linux-gnu/libc/el \
>     -I$MIPS/mips-linux-gnu/libc/usr/include \
>     -B$MIPS/lib/gcc/mips-linux-gnu/4.5.2/el \
>     -L$MIPS/lib/gcc/mips-linux-gnu/4.5.2/el \
>     -integrated-as
-isysroot $MIPS/mips-linux-gnu/libc might be better than the -I.
Your command doesn't give you the special handling for system headers.

Joerg

Hi,

Thank your for your confirmation.

I had been looking for llvm compiler's option for compiler, assembler, and
linker replacing asserted ones to target ones. As a cross-compiler, a
cross-assembler, and a cross-linker for target have been already created in
toolchain, they can be replaced through llvm compileration.

Wishes,
Noriko 


-----Original message-----
From:NAKAMURA Takumi <geek4civic at gmail.com>
To:noriko-e at fc.ritsumei.ac.jp
Cc:llvmdev <llvmdev at cs.uiuc.edu>,cfe-dev <cfe-dev at
cs.uiuc.edu>,Akira Hatanaka <ahatanaka at mips.com>,reed kotler
<rkotler at mips.com>
Date:Sat, 7 Jul 2012 00:12:24 +0900
Subject:Re: [LLVMdev] how to change a compiler from a host to a target in
Clang's assembler and linker

Konbanwa, Etani san,

It might be clang driver issue. Move to cfe-dev.

2012/7/4 ETANI NORIKO <noriko-e at
fc.ritsumei.ac.jp>:
> I would like to ask you how to use Clang in cross-compile environment. My
environment is as follows:
> ------
> HOST: 32-bit Fedora 16 with Intel Core i7
>       gcc/g++ compiler available
> TARGET: 32-bit mips-typed linux
>       gnu gcc/g++ for 32-bit mips-typed linux available
> ------
* What do you specify as -target? (eg. clag -c -target i686-pc-mingw32)

* Which toolchain have you installed and what is the prefix of it?
AFAIU, GNU binutils for the target would be essential.
(eg. /usr/bin/i686-pc-mingw32-ld)
> As Clang's option is "-c" in use, my programs are compiled
and linked under a host machine's environment (in my case, 32-bit Fedora 16
is a host OS with Intel Core i7).
>
> In order to compile and link them under a target's environment (in my
case, mips-typed linux gcc/g++ can work), in Clang’s "Assembler" and
"Linker" processes, a compiler on a host should be changed to one on a
target. Still now, I cannot find out a file to set a compiler for
"Assembler" and "Linker" in Clang. Please advise me how to
change a compiler from a host one to a target one.
* Have you tried "clang -c -integrated-as"?

To Mips guys: Do you think Mips MC assembler would work?

FYI, workaround.
clang -S hogehoge.c
target-gcc -c hogehoge.s
target-gcc -o fugafuga hogehoge.o ...
(I don't know how mips-clang would be mature)

...Takumi (中村)

Hi,

Thank you for your information.
I can learn how to use "ln" command to replace an assumed compiler to
another one.

Wishes,
Noriko 

-----Original message-----
From:Simon Atanasyan <satanasyan at mips.com>
To:noriko-e at fc.ritsumei.ac.jp
Cc:llvmdev <llvmdev at cs.uiuc.edu>,clang-dev Developers <cfe-dev at
cs.uiuc.edu>
Date:Fri, 6 Jul 2012 22:40:58 +0400
Subject:Re: [LLVMdev] how to change a compiler from a host to a target in
Clang's assembler and linker

Hi,

On Wed, Jul 4, 2012 at 9:21 AM, ETANI NORIKO <noriko-e at
fc.ritsumei.ac.jp> wrote:
> Please advise me how to change a compiler from a host one to a target one.
Suppose MIPS toolchain is installed in the $MIPS folder (i.e.
mips-linux-gnu-gcc is in the $MIPS/bin folder). Note, if you want to
generate little-endian code and/or 64-bit code, you have to create the
following links in the $MIPS/bin folder:
* Little-endian 32-bit
    ln -s mips-linux-gnu-ld mipsel-linux-gnu-ld
    ln -s mips-linux-gnu-as mipsel-linux-gnu-as
* Little-endian 64-bit
    ln -s mips-linux-gnu-ld mips64el-linux-gnu-ld
    ln -s mips-linux-gnu-as mips64el-linux-gnu-as
* Big-endian 64-bit
    ln -s mips-linux-gnu-ld mips64-linux-gnu-ld
    ln -s mips-linux-gnu-as mips64-linux-gnu-as

If you use integrated assembler (turned on by -integrated-as option)
you can skip mips-linux-gnu-as links creation.

Exact command line options depends on used toolchain. Examples below
work for Mentor Graphics Toolchain version 2011.09-75
(https://sourcery.mentor.com/GNUToolchain/subscription3130?lite=MIPS).

* Little-endian 32-bit
$ clang -target mipsel-linux-gnu main.c -static \
    --sysroot $MIPS/mips-linux-gnu/libc/el \
    -I$MIPS/mips-linux-gnu/libc/usr/include \
    -B$MIPS/lib/gcc/mips-linux-gnu/4.5.2/el \
    -L$MIPS/lib/gcc/mips-linux-gnu/4.5.2/el \
    -integrated-as

* Big-endian 32-bit
$ clang -target mips-linux-gnu main.c -static \
    --sysroot $MIPS/mips-linux-gnu/libc \
    -I$MIPS/mips-linux-gnu/libc/usr/include \
    -B$MIPS/lib/gcc/mips-linux-gnu/4.5.2 \
    -L$MIPS/lib/gcc/mips-linux-gnu/4.5.2 \
    -integrated-as

* Little-endian 64-bit
$ clang -target mips64el-linux-gnu main.c -static \
    --sysroot $MIPS/mips-linux-gnu/libc/el \
    -I$MIPS/mips-linux-gnu/libc/usr/include \
    -B$MIPS/lib/gcc/mips-linux-gnu/4.5.2/el/64 \
    -L$MIPS/lib/gcc/mips-linux-gnu/4.5.2/el/64

* Big-endian 64-bit
$ clang -target mips64-linux-gnu main.c -static \
    --sysroot $MIPS/mips-linux-gnu/libc \
    -I$MIPS/mips-linux-gnu/libc/usr/include \
    -B$MIPS/lib/gcc/mips-linux-gnu/4.5.2/64 \
    -L$MIPS/lib/gcc/mips-linux-gnu/4.5.2/64

If that does not work for you, could you please provide more information:
1. What command line options do you use?
2. What toolchain do you use and where is it installed?
3. What errors do you get?

--
Simon