llvm dev - Aug 2012 - [LLVMdev] Is cross-compiling for ARM on x86 with llvm/Clang possible?

Hello list

I think I really finally found a way to crossbuild a binary for ARM using
Clang/llvm.

This message would be a documentation for someone who may concern for the
same issue with me.

- Target : TOSHIBA AC100 / Ubuntu 12.04 (https://wiki.ubuntu.com/ARM/**
TEGRA/AC100 <https://wiki.ubuntu.com/ARM/TEGRA/AC100>)
- Host : i386 Desktop PC / Ubuntu 12.04
- Toolchain on host : sudo apt-get install gcc-arm-linux-gnueabi
- Clang/llvm compile :  http://clang.llvm.org/get_started.html
- Command string for crossbuild : ./clang -v --save-temps -ccc-host-triple
arm-linux-gnueabi --sysroot=/usr/arm-linux-gnueabi -gcc-toolchain /usr/
-Wl,-dynamic-linker,/lib/ld-linux-armhf.so.3 hello.c -o hello

During this testing I found something like a bug in Clang or llvm.
Please note the Command string for crossbuild above.
Problem occurs if "-ccc-host-triple" gets
"arm-linux-gnueabihf" instead
of "arm-linux-gnueabi".
Problem is that ld is called with a incomplete or no path for libgcc,
crtbegin.o and crtend.o "-gcc-toolchain" options doesn't seem to
work.
Workaroud for this problem is using a command string like below.

./clang -v --save-temps -ccc-host-triple arm-linux-gnueabihf
-mfloat-abi=hard -mfpu=vfpv3-d16 --sysroot=/usr/arm-linux-gnueabihf
-gcc-toolchain /usr/ -Wl,-dynamic-linker,/lib/ld-linux-armhf.so.3
-L/usr/lib/gcc/arm-linux-gnueabihf/4.6
-L/usr/lib/gcc/arm-linux-gnueabihf/4.6/../../../../arm-linux-gnueabihf/lib/../lib
-L/usr/lib/gcc/arm-linux-gnueabihf/4.6/../../../../arm-linux-gnueabihf/lib
-L/lib/arm-linux-gnueabihf -L/usr/lib/arm-linux-gnueabihf -L/usr/lib -L/lib
hello.c -o hello

Note all library path have to be specified. And more importantly crtend.o
and crtbegin.o have to be symbolic-linked!!
I tested with a toolchain for arm-linux-gnueabihf for this test.(sudo
apt-get install gcc-arm-linux-gnueabihf)

Thank you everyone who answered for my questions.

Journeyer J. Joh

(ps. For Sid, The final binary "hello" prints "not a dynamic
executable"
when asked with "ldd". But it runs very well. ^^)


2012/6/27 Sid Manning <sidneym at codeaurora.org>
> On 06/27/12 07:24, Journeyer J. Joh wrote:
>
>> Hello,
>>
>> With your kind concern and help, I now can make a binary for ARM
target.
>>
>> ./clang -v --save-temps -ccc-host-triple arm-none-linux-gnueabi
>> --sysroot=/home/hum/Documents/**Projects/arm_toolchain/arm-**
>> 2010.09/arm-none-linux-**gnueabi/libc
>> -gcc-toolchain /home/hum/Documents/Projects/**arm_toolchain/arm-2010.09
>> hello.c -o hello
>>
>> The build command is shown above.
>>
>> After that, I prepared an ARM laptop, AC100 - TOSHIBA.
>> I installed Ubuntu 12.04 in the way guided from the link below.
>>
>>
https://wiki.ubuntu.com/ARM/**TEGRA/AC100<https://wiki.ubuntu.com/ARM/TEGRA/AC100>
>>
>> So I moved the final binary from host PC to AC100 and executed.
>> But the binary DIDN'T RUN.
>>
>> $./hello
>>
>> returns an error message below.
>>
>> bash: ./hello: No such file hello
>>
>>
> You could try readelf -l hello and check the INTERP header.  When I've
> seen this message usually PT_INTERP points to something that the kernel
> can't find.
>
>
>
>  I need to understand why it doesn't run on ARM laptop.
>>
>> I compiled another sample program hi.c on the ARM laptop and compared
>> both - the one cross compiled "hello" and the other self host
compiled
>> "hi".
>>
>> Output message of utility "file" is almost the same except
Linux
>> version, one is 2.6.16 and the other is 2.6.31. But the output of
"ldd"
>> shows something meaningful.
>>
>
> This is curious based on the output from ldd below, does file report each
> as, "dynamically linked".
>
>
>
>> ldd hi
>>     libc.so.6 => /lib/arm-linux-gnueabihf/libc.**so.6 (0xb6ecf000)
>>     /lib/ld-linux-armhf.so.3 (0xb6fc3000)
>>
>> ldd hello
>>     not a dynamic executable
>>
>>
>>

-- 
----------------------------------------
Journeyer J. Joh
o o s a p r o g r a m m e r
a t
g m a i l  d o t  c o m
----------------------------------------
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Hi Journeyer

First, thank you so much for your updates on your experiments.
I am currently following your steps but have found myself stuck with the
following error:

/usr/lib/gcc/arm-linux-gnueabi/4.6/../../../../arm-linux-gnueabi/bin/ld:
this linker was not configured to use sysroots
clang: error: linker command failed with exit code 1 (use -v to see
invocation)

I used the command string you wrote :
./clang -v --save-temps -ccc-host-triple arm-linux-gnueabi
--sysroot=/usr/arm-linux-gnueabi -gcc-toolchain /usr/
-Wl,-dynamic-linker,/lib/ld-linux-armhf.so.3 hello.c -o hello

Can you help me identify the problem?
I'm also really interested in cross compiling ARM and x86.

For the complete logs of the above command, please refer below :

clang version 3.1 (branches/release_31)
Target: arm--linux-gnueabi
Thread model: posix
 "/home/jedd10-04/TOOC/LLVM-3.1/llvm-3.1.src/build/Debug+Asserts/bin/clang"
-cc1 -triple armv4t--linux-gnueabi -E -disable-free -main-file-name hello.c
-mrelocation-model static -mdisable-fp-elim -mconstructor-aliases
-target-abi aapcs-linux -target-cpu arm7tdmi -mfloat-abi soft
-target-feature +soft-float-abi -target-linker-version 2.20.1
-momit-leaf-frame-pointer -v -resource-dir
/home/jedd10-04/TOOC/LLVM-3.1/llvm-3.1.src/build/Debug+Asserts/bin/../lib/clang/3.1
-isysroot /usr/arm-linux-gnueabi -fmodule-cache-path
/var/tmp/clang-module-cache -internal-isystem
/usr/arm-linux-gnueabi/usr/local/include -internal-isystem
/home/jedd10-04/TOOC/LLVM-3.1/llvm-3.1.src/build/Debug+Asserts/bin/../lib/clang/3.1/include
-internal-externc-isystem /usr/arm-linux-gnueabi/include
-internal-externc-isystem /usr/arm-linux-gnueabi/usr/include
-fno-dwarf-directory-asm -fdebug-compilation-dir
/home/jedd10-04/TOOC/clang-samples -ferror-limit 19 -fmessage-length 132
-mstackrealign -fno-signed-char -fgnu-runtime -fobjc-runtime-has-arc
-fobjc-runtime-has-weak -fobjc-fragile-abi -fdiagnostics-show-option
-fcolor-diagnostics -o hello.i -x c hello.c
clang -cc1 version 3.1 based upon LLVM 3.1 default target
x86_64-unknown-linux-gnu
ignoring nonexistent directory
"/usr/arm-linux-gnueabi/usr/local/include"
ignoring nonexistent directory "/usr/arm-linux-gnueabi/usr/include"
#include "..." search starts here:
#include <...> search starts here:

/home/jedd10-04/TOOC/LLVM-3.1/llvm-3.1.src/build/Debug+Asserts/bin/../lib/clang/3.1/include
 /usr/arm-linux-gnueabi/include
End of search list.
 "/home/jedd10-04/TOOC/LLVM-3.1/llvm-3.1.src/build/Debug+Asserts/bin/clang"
-cc1 -triple armv4t--linux-gnueabi -S -disable-free -main-file-name hello.c
-mrelocation-model static -mdisable-fp-elim -mconstructor-aliases
-target-abi aapcs-linux -target-cpu arm7tdmi -mfloat-abi soft
-target-feature +soft-float-abi -target-linker-version 2.20.1
-momit-leaf-frame-pointer -v -resource-dir
/home/jedd10-04/TOOC/LLVM-3.1/llvm-3.1.src/build/Debug+Asserts/bin/../lib/clang/3.1
-fno-dwarf-directory-asm -fdebug-compilation-dir
/home/jedd10-04/TOOC/clang-samples -ferror-limit 19 -fmessage-length 132
-mstackrealign -fno-signed-char -fgnu-runtime -fobjc-runtime-has-arc
-fobjc-runtime-has-weak -fobjc-fragile-abi -fdiagnostics-show-option
-fcolor-diagnostics -o hello.s -x cpp-output hello.i
clang -cc1 version 3.1 based upon LLVM 3.1 default target
x86_64-unknown-linux-gnu
#include "..." search starts here:
End of search list.
 "/usr/lib/gcc/arm-linux-gnueabi/4.6/../../../../arm-linux-gnueabi/bin/as"
-o hello.o hello.s
 "/usr/lib/gcc/arm-linux-gnueabi/4.6/../../../../arm-linux-gnueabi/bin/ld"
--sysroot=/usr/arm-linux-gnueabi -z relro -X --hash-style=both --build-id
--eh-frame-hdr -m armelf_linux_eabi -dynamic-linker /lib/ld-linux.so.3 -o
hello /usr/arm-linux-gnueabi/lib/crt1.o /usr/arm-linux-gnueabi/lib/crti.o
/usr/lib/gcc/arm-linux-gnueabi/4.6/crtbegin.o
-L/usr/lib/gcc/arm-linux-gnueabi/4.6 -L/usr/arm-linux-gnueabi/lib
-dynamic-linker /lib/ld-linux-armhf.so.3 hello.o -lgcc --as-needed -lgcc_s
--no-as-needed -lc -lgcc --as-needed -lgcc_s --no-as-needed
/usr/lib/gcc/arm-linux-gnueabi/4.6/crtend.o
/usr/arm-linux-gnueabi/lib/crtn.o
/usr/lib/gcc/arm-linux-gnueabi/4.6/../../../../arm-linux-gnueabi/bin/ld:
this linker was not configured to use sysroots
clang: error: linker command failed with exit code 1 (use -v to see
invocation)



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Hello Tsukishiro

First of all, I am in a learning stage of LLVM and Clang. This means I
am not an expert! ^^;

The final trial I succeeded was under the environment below.

- Target : TOSHIBA AC100 / Ubuntu 12.04 (https://wiki.ubuntu.com/ARM/**
TEGRA/AC100 <https://wiki.ubuntu.com/ARM/TEGRA/AC100>)
- Host : i386 Desktop PC / Ubuntu 12.04
- Toolchain on host : sudo apt-get install gcc-arm-linux-gnueabi
- Clang/llvm compile :  http://clang.llvm.org/get_started.html

I wonder your environment.

- Target :
- Host :
- Toolchain on host : How did you get your toolchain?
- Clang/llvm compile : How did you compile Clang/llvm?

I tested successfully with a command below.

- Command string for crossbuild : ./clang -v --save-temps -ccc-host-triple
arm-linux-gnueabi --sysroot=/usr/arm-linux-gnueabi -gcc-toolchain /usr/
-Wl,-dynamic-linker,/lib/ld-linux-armhf.so.3 hello.c -o hello

Important options are shown below.

-ccc-host-triple : arm-linux-gnueabi
--sysroot : /usr/arm-linux-gnueabi
-gcc-toolchain : /usr/
-Wl,-dynamic-linker,/lib/ld-linux-armhf.so.3

I want to know your command string not mine. Could you write it to me?

I am afraid I could fail to help you.... I am not an expert.. Please
consider this.

Best regards
Journeyer


2012/8/29 tsukishiro <tsukishiro88 at gmail.com>:
> Hi Journeyer
>
> First, thank you so much for your updates on your experiments.
> I am currently following your steps but have found myself stuck with the
> following error:
>
> /usr/lib/gcc/arm-linux-gnueabi/4.6/../../../../arm-linux-gnueabi/bin/ld:
> this linker was not configured to use sysroots
> clang: error: linker command failed with exit code 1 (use -v to see
> invocation)
>
> I used the command string you wrote :
> ./clang -v --save-temps -ccc-host-triple arm-linux-gnueabi
> --sysroot=/usr/arm-linux-gnueabi -gcc-toolchain /usr/
> -Wl,-dynamic-linker,/lib/ld-linux-armhf.so.3 hello.c -o hello
>
> Can you help me identify the problem?
> I'm also really interested in cross compiling ARM and x86.
>
> For the complete logs of the above command, please refer below :
>
> clang version 3.1 (branches/release_31)
> Target: arm--linux-gnueabi
> Thread model: posix
> 
"/home/jedd10-04/TOOC/LLVM-3.1/llvm-3.1.src/build/Debug+Asserts/bin/clang"
> -cc1 -triple armv4t--linux-gnueabi -E -disable-free -main-file-name hello.c
> -mrelocation-model static -mdisable-fp-elim -mconstructor-aliases
> -target-abi aapcs-linux -target-cpu arm7tdmi -mfloat-abi soft
> -target-feature +soft-float-abi -target-linker-version 2.20.1
> -momit-leaf-frame-pointer -v -resource-dir
>
/home/jedd10-04/TOOC/LLVM-3.1/llvm-3.1.src/build/Debug+Asserts/bin/../lib/clang/3.1
> -isysroot /usr/arm-linux-gnueabi -fmodule-cache-path
> /var/tmp/clang-module-cache -internal-isystem
> /usr/arm-linux-gnueabi/usr/local/include -internal-isystem
>
/home/jedd10-04/TOOC/LLVM-3.1/llvm-3.1.src/build/Debug+Asserts/bin/../lib/clang/3.1/include
> -internal-externc-isystem /usr/arm-linux-gnueabi/include
> -internal-externc-isystem /usr/arm-linux-gnueabi/usr/include
> -fno-dwarf-directory-asm -fdebug-compilation-dir
> /home/jedd10-04/TOOC/clang-samples -ferror-limit 19 -fmessage-length 132
> -mstackrealign -fno-signed-char -fgnu-runtime -fobjc-runtime-has-arc
> -fobjc-runtime-has-weak -fobjc-fragile-abi -fdiagnostics-show-option
> -fcolor-diagnostics -o hello.i -x c hello.c
> clang -cc1 version 3.1 based upon LLVM 3.1 default target
> x86_64-unknown-linux-gnu
> ignoring nonexistent directory
"/usr/arm-linux-gnueabi/usr/local/include"
> ignoring nonexistent directory
"/usr/arm-linux-gnueabi/usr/include"
> #include "..." search starts here:
> #include <...> search starts here:
>
>
/home/jedd10-04/TOOC/LLVM-3.1/llvm-3.1.src/build/Debug+Asserts/bin/../lib/clang/3.1/include
>  /usr/arm-linux-gnueabi/include
> End of search list.
> 
"/home/jedd10-04/TOOC/LLVM-3.1/llvm-3.1.src/build/Debug+Asserts/bin/clang"
> -cc1 -triple armv4t--linux-gnueabi -S -disable-free -main-file-name hello.c
> -mrelocation-model static -mdisable-fp-elim -mconstructor-aliases
> -target-abi aapcs-linux -target-cpu arm7tdmi -mfloat-abi soft
> -target-feature +soft-float-abi -target-linker-version 2.20.1
> -momit-leaf-frame-pointer -v -resource-dir
>
/home/jedd10-04/TOOC/LLVM-3.1/llvm-3.1.src/build/Debug+Asserts/bin/../lib/clang/3.1
> -fno-dwarf-directory-asm -fdebug-compilation-dir
> /home/jedd10-04/TOOC/clang-samples -ferror-limit 19 -fmessage-length 132
> -mstackrealign -fno-signed-char -fgnu-runtime -fobjc-runtime-has-arc
> -fobjc-runtime-has-weak -fobjc-fragile-abi -fdiagnostics-show-option
> -fcolor-diagnostics -o hello.s -x cpp-output hello.i
> clang -cc1 version 3.1 based upon LLVM 3.1 default target
> x86_64-unknown-linux-gnu
> #include "..." search starts here:
> End of search list.
> 
"/usr/lib/gcc/arm-linux-gnueabi/4.6/../../../../arm-linux-gnueabi/bin/as"
> -o hello.o hello.s
> 
"/usr/lib/gcc/arm-linux-gnueabi/4.6/../../../../arm-linux-gnueabi/bin/ld"
> --sysroot=/usr/arm-linux-gnueabi -z relro -X --hash-style=both --build-id
> --eh-frame-hdr -m armelf_linux_eabi -dynamic-linker /lib/ld-linux.so.3 -o
> hello /usr/arm-linux-gnueabi/lib/crt1.o /usr/arm-linux-gnueabi/lib/crti.o
> /usr/lib/gcc/arm-linux-gnueabi/4.6/crtbegin.o
> -L/usr/lib/gcc/arm-linux-gnueabi/4.6 -L/usr/arm-linux-gnueabi/lib
> -dynamic-linker /lib/ld-linux-armhf.so.3 hello.o -lgcc --as-needed -lgcc_s
> --no-as-needed -lc -lgcc --as-needed -lgcc_s --no-as-needed
> /usr/lib/gcc/arm-linux-gnueabi/4.6/crtend.o
> /usr/arm-linux-gnueabi/lib/crtn.o
> /usr/lib/gcc/arm-linux-gnueabi/4.6/../../../../arm-linux-gnueabi/bin/ld:
> this linker was not configured to use sysroots
> clang: error: linker command failed with exit code 1 (use -v to see
> invocation)
>
>
>
> --
> View this message in context:
http://llvm.1065342.n5.nabble.com/Is-cross-compiling-for-ARM-on-x86-with-llvm-Clang-possible-tp46279p48471.html
> Sent from the LLVM - Dev mailing list archive at Nabble.com.
> _______________________________________________
> LLVM Developers mailing list
> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev


-- 
----------------------------------------
Journeyer J. Joh
o o s a p r o g r a m m e r
a t
g m a i l  d o t  c o m
----------------------------------------

> /usr/lib/gcc/arm-linux-gnueabi/4.6/../../../../arm-linux-gnueabi/bin/ld:
> this linker was not configured to use sysroots
> clang: error: linker command failed with exit code 1 (use -v to see
> invocation)
Well, the error is pretty clear - your linker does not support sysroot.

-- 
With best regards, Anton Korobeynikov
Faculty of Mathematics and Mechanics, Saint Petersburg State University