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

Wed Jun 20 01:59:07 PDT 2012

Hello,

Please ignore my previous email.
I received the final binary with command below.
I had to get rid of the option, -emit-llvm.

./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
hello.c

file hello.i
hello.i: ASCII C program text

file hello.s
hello.s: ASCII assembler program text

/home/hum/Documents/Projects/arm_toolchain/arm-2010.09/bin/arm-none-linux-gnueabi-as
-mfloat-abi=softfp -o hello.o hello.s

file hello.o
hello.o: ELF 32-bit LSB relocatable, ARM, version 1 (SYSV), not stripped

/home/hum/Documents/Projects/arm_toolchain/arm-2010.09/bin/arm-none-linux-gnueabi-ld
--sysroot=/home/hum/Documents/Projects/arm_toolchain/arm-2010.09/arm-none-linux-gnueabi/libc
-z relro -X --hash-style=gnu --build-id --eh-frame-hdr -m armelf_linux_eabi
-o a.out
/home/hum/Documents/Projects/arm_toolchain/arm-2010.09/arm-none-linux-gnueabi/libc/usr/lib/crt1.o
/home/hum/Documents/Projects/arm_toolchain/arm-2010.09/arm-none-linux-gnueabi/libc/usr/lib/crti.o
/home/hum/Documents/Projects/arm_toolchain/arm-2010.09/lib/gcc/arm-none-linux-gnueabi/4.5.1/armv4t/crtbegin.o
-L/home/hum/Documents/Projects/arm_toolchain/arm-2010.09/arm-none-linux-gnueabi/libc/lib
-L/home/hum/Documents/Projects/arm_toolchain/arm-2010.09/arm-none-linux-gnueabi/libc/usr/lib
-L/home/hum/Documents/Projects/arm_toolchain/arm-2010.09/lib/gcc/arm-none-linux-gnueabi/4.5.1/armv4t
hello.o -lgcc --as-needed -lgcc_s --no-as-needed -lc -lgcc --as-needed
-lgcc_s --no-as-needed
/home/hum/Documents/Projects/arm_toolchain/arm-2010.09/lib/gcc/arm-none-linux-gnueabi/4.5.1/armv4t/crtend.o
/home/hum/Documents/Projects/arm_toolchain/arm-2010.09/arm-none-linux-gnueabi/libc/usr/lib/crtn.o

file a.out
a.out: ELF 32-bit LSB executable, ARM, version 1 (SYSV), dynamically linked
(uses shared libs), for GNU/Linux 2.6.16,
BuildID[sha1]=0x7825ca07341b2f337c4f10b5711055c997820a9c, not stripped

The only thing remained is to specify the cross tool chain location to the
clang so that clang uses cross-as and ld automatically.

If someone provide these information, it would be welcomed!

Thank you very much.

Journeyer J. Joh

2012/6/20 Journeyer J. Joh <oosaprogrammer at gmail.com>

> Hello,
>
> Thank you for your kind attention to my issue and your help.
>
> I changed the tool chain and tried again. And there is a little progress
> but still have some problem.
>
> Using --sysroot doesn't make clang use linker(ld) in the cross tool.
> Most important question is how I can make clang use cross tool linker.
>
> Let me show you my experiment and questions below.
> There are two questions.
>
> [Run]
> ./clang -v --save-temps -emit-llvm -ccc-host-triple arm-none-linux-gnueabi
> --sysroot=/home/hum/Documents/Projects/arm_toolchain/arm-2010.09/arm-none-linux-gnueabi/libc
> hello.c
>
> [Question]
> 1. How am I supposed to use --sysroot? Though I used "--sysroot" above,
> Clang uses native linker, "/usr/bin/ld" not the one in the tool chain,
> "/home/hum/Documents/Projects/arm_toolchain/arm-2010.09/bin/arm-none-linux-gnueabi-ld".
>
> [Output]
> clang version 3.2 (trunk 158784)
> Target: arm-none-linux-gnueabi
> Thread model: posix
>
> "/home/hum/Documents/Projects/clang_llvm/build/Debug+Asserts/bin/clang"
> -cc1
> -triple armv4t-none-linux-gnueabi
> -E
> -disable-free
> -main-file-name hello.c
> -mrelocation-model static
> -mdisable-fp-elim
> -fmath-errno
> -mconstructor-aliases
> -target-abi aapcs-linux
> -target-cpu arm7tdmi
> -mfloat-abi soft
> -target-feature +soft-float-abi
> -target-linker-version 2.22
> -momit-leaf-frame-pointer
> -v
> -resource-dir
> /home/hum/Documents/Projects/clang_llvm/build/Debug+Asserts/bin/../lib/clang/3.2
> -isysroot
> /home/hum/Documents/Projects/arm_toolchain/arm-2010.09/arm-none-linux-gnueabi/libc
> -fmodule-cache-path /var/tmp/clang-module-cache
> -internal-isystem
> /home/hum/Documents/Projects/arm_toolchain/arm-2010.09/arm-none-linux-gnueabi/libc/usr/local/include
> -internal-isystem
> /home/hum/Documents/Projects/clang_llvm/build/Debug+Asserts/bin/../lib/clang/3.2/include
> -internal-externc-isystem
> /home/hum/Documents/Projects/arm_toolchain/arm-2010.09/arm-none-linux-gnueabi/libc/include
> -internal-externc-isystem
> /home/hum/Documents/Projects/arm_toolchain/arm-2010.09/arm-none-linux-gnueabi/libc/usr/include
> -fno-dwarf-directory-asm
> -fdebug-compilation-dir
> /home/hum/Documents/Projects/clang_llvm/build/Debug+Asserts/bin
> -ferror-limit 19
> -fmessage-length 205
> -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 3.2 based upon LLVM 3.2svn default target
> i386-pc-linux-gnu
> ignoring nonexistent directory
> "/home/hum/Documents/Projects/arm_toolchain/arm-2010.09/arm-none-linux-gnueabi/libc/usr/local/include"
> ignoring nonexistent directory
> "/home/hum/Documents/Projects/arm_toolchain/arm-2010.09/arm-none-linux-gnueabi/libc/include"
> #include "..." search starts here:
> #include <...> search starts here:
>
>  /home/hum/Documents/Projects/clang_llvm/build/Debug+Asserts/bin/../lib/clang/3.2/include
>
>  /home/hum/Documents/Projects/arm_toolchain/arm-2010.09/arm-none-linux-gnueabi/libc/usr/include
> End of search list.
>
>
> "/home/hum/Documents/Projects/clang_llvm/build/Debug+Asserts/bin/clang"
> -cc1
> -triple armv4t-none-linux-gnueabi
> -emit-llvm-bc
> -disable-free
> -main-file-name hello.c
> -mrelocation-model static
> -mdisable-fp-elim
> -fmath-errno
> -mconstructor-aliases
> -target-abi aapcs-linux
> -target-cpu arm7tdmi
> -mfloat-abi soft
> -target-feature +soft-float-abi
> -target-linker-version 2.22
> -momit-leaf-frame-pointer
> -v
> -resource-dir
> /home/hum/Documents/Projects/clang_llvm/build/Debug+Asserts/bin/../lib/clang/3.2
> -fno-dwarf-directory-asm
> -fdebug-compilation
> -dir /home/hum/Documents/Projects/clang_llvm/build/Debug+Asserts/bin
> -ferror-limit 19
> -fmessage-length 205
> -mstackrealign
> -fno-signed-char
> -fgnu-runtime
> -fobjc-runtime-has-arc
> -fobjc-runtime-has-weak
> -fobjc-fragile-abi
> -fdiagnostics-show-option
> -fcolor-diagnostics
>  -o hello.o
> -x cpp-output
> hello.i
>
> clang -cc1 version 3.2 based upon LLVM 3.2svn default target
> i386-pc-linux-gnu
> #include "..." search starts here:
> End of search list.
>
>
> "/usr/bin/ld" <<<<<<<<<< Problem #1 : wrong linker! ld in cross toolchain
> is needed!
>
> --sysroot=/home/hum/Documents/Projects/arm_toolchain/arm-2010.09/arm-none-linux-gnueabi/libc
> -z relro
> -X
> --hash-style=gnu
> --build-id
> --eh-frame-hdr
> -m armelf_linux_eabi
> -dynamic-linker /lib/ld-linux.so.3 <<<<<<<<<< Problem #2 : All libraries
> have to be of the cross toolchain!
> -o a.out
>
> /home/hum/Documents/Projects/arm_toolchain/arm-2010.09/arm-none-linux-gnueabi/libc/usr/lib/crt1.o
>
> /home/hum/Documents/Projects/arm_toolchain/arm-2010.09/arm-none-linux-gnueabi/libc/usr/lib/crti.o
> crtbegin.o <<<<<<<<<< Problem #3 : All libraries have to be of the cross
> toolchain!
> (/home/hum/Documents/Projects/arm_toolchain/arm-2010.09/lib/gcc/arm-none-linux-gnueabi/4.5.1/armv4t/crtbegin.o
> needs to be used!!!)
>
> -L/home/hum/Documents/Projects/arm_toolchain/arm-2010.09/arm-none-linux-gnueabi/libc/lib
>
> -L/home/hum/Documents/Projects/arm_toolchain/arm-2010.09/arm-none-linux-gnueabi/libc/usr/lib
> -plugin
> /home/hum/Documents/Projects/clang_llvm/build/Debug+Asserts/bin/../lib/LLVMgold.so
> <<<<<<<<<< Problem #4 : There is no LLVMgold.so in llvm/clang bin/
> hello.o
> -lgcc
> --as-needed
> -lgcc_s
> --no-as-needed
> -lc
> -lgcc
> --as-needed
> -lgcc_s
> --no-as-needed
> crtend.o <<<<<<<<<< Problem #5 : All libraries have to be of the cross
> toolchain!
> (/home/hum/Documents/Projects/arm_toolchain/arm-2010.09/lib/gcc/arm-none-linux-gnueabi/4.5.1/armv4t/crtend.o
> needs to be used!!!)
>
> /home/hum/Documents/Projects/arm_toolchain/arm-2010.09/arm-none-linux-gnueabi/libc/usr/lib/crtn.o
>
> /usr/bin/ld: unrecognised emulation mode: armelf_linux_eabi
> Supported emulations: elf_i386 i386linux elf32_x86_64 elf_x86_64 elf_l1om
> elf_k1om
> clang: error: linker command failed with exit code 1 (use -v to see
> invocation)
>
>
> Problem #1 : wrong linker! ld in cross toolchain is needed!
> Problem #2 : All libraries have to be of the cross toolchain!
> Problem #3 : All libraries have to be of the cross toolchain!
> (/home/hum/Documents/Projects/arm_toolchain/arm-2010.09/lib/gcc/arm-none-linux-gnueabi/4.5.1/armv4t/crtbegin.o
> needs to be used!!!)
> Problem #4 : There is no LLVMgold.so in llvm/clang bin/
> Problem #5 : All libraries have to be of the cross toolchain!
> (/home/hum/Documents/Projects/arm_toolchain/arm-2010.09/lib/gcc/arm-none-linux-gnueabi/4.5.1/armv4t/crtend.o
> needs to be used!!!)
>
>
> Workaround #1 : tried to run
> /home/hum/Documents/Projects/arm_toolchain/arm-2010.09/arm-none-linux-gnueabi/bin/ld
> manually.
> Workaround #2 : Ignored this library in this manual run.
> Workaround #3 :
> /home/hum/Documents/Projects/arm_toolchain/arm-2010.09/lib/gcc/arm-none-linux-gnueabi/4.5.1/armv4t/crtbegin.o
> used instead.
> Workaround #4 : Ignored this library in this manual run.
> Workaround #5 :
> /home/hum/Documents/Projects/arm_toolchain/arm-2010.09/lib/gcc/arm-none-linux-gnueabi/4.5.1/armv4t/crtend.o
> used instead.
>
>
>
> [Workaround - Manual Run]
> /home/hum/Documents/Projects/arm_toolchain/arm-2010.09/bin/arm-none-linux-gnueabi-ld
> --sysroot=/home/hum/Documents/Projects/arm_toolchain/arm-2010.09/arm-none-linux-gnueabi/libc
> -z relro -X --hash-style=gnu --build-id --eh-frame-hdr -m armelf_linux_eabi
> -o a.out
> /home/hum/Documents/Projects/arm_toolchain/arm-2010.09/arm-none-linux-gnueabi/libc/usr/lib/crt1.o
> /home/hum/Documents/Projects/arm_toolchain/arm-2010.09/arm-none-linux-gnueabi/libc/usr/lib/crti.o
> /home/hum/Documents/Projects/arm_toolchain/arm-2010.09/lib/gcc/arm-none-linux-gnueabi/4.5.1/armv4t/crtbegin.o
> -L/home/hum/Documents/Projects/arm_toolchain/arm-2010.09/arm-none-linux-gnueabi/libc/lib
> -L/home/hum/Documents/Projects/arm_toolchain/arm-2010.09/arm-none-linux-gnueabi/libc/usr/lib
> hello.o -lgcc --as-needed -lgcc_s --no-as-needed -lc -lgcc --as-needed
> -lgcc_s --no-as-needed
> /home/hum/Documents/Projects/arm_toolchain/arm-2010.09/lib/gcc/arm-none-linux-gnueabi/4.5.1/armv4t/crtend.o
> /home/hum/Documents/Projects/arm_toolchain/arm-2010.09/arm-none-linux-gnueabi/libc/usr/lib/crtn.o
>
> [Output]
> hello.o: file not recognized: File format not recognized
>
> [Test]
> "file hello.o" prints out :
> hello.o: LLVM bitcode
>
> [Question]
> 2. Am I using a wrong cross toolchain? Doesn't feeding LLVM bitcode to the
> ARM cross linker make sense?
>
>
>
> Thank you very much.
>
> Sincerely
> Journeyer J. Joh
>
>
>
>
> 2012/6/19 Anton Korobeynikov <anton at korobeynikov.info>
>
>> Hello
>>
>> > ./clang -v -emit-llvm -ccc-host-triple arm-none-linux-gnueabi
>> > -I/home/hum/Documents/Projects/llvm_clang/gnuarm-4.0.2/arm-elf/include
>> > -L/home/hum/Documents/Projects/llvm_clang/gnuarm-4.0.2/arm-elf/bin
>> hello.c
>> You forgot about sysroot here.
>>
>> > /home/hum/Documents/Projects/llvm_clang/gnuarm-4.0.2/arm-elf/bin/ld:
>> > unrecognised emulation mode: armelf_linux_eabi
>> > Supported emulations: armelf
>> 1. Your ld is too old
>> 2. Your ld was built for arm-elf, not arm-linux-eabi
>>
>> --
>> With best regards, Anton Korobeynikov
>> Faculty of Mathematics and Mechanics, Saint Petersburg State University
>>
>
>
>
> --
> ----------------------------------------
> 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
> ----------------------------------------
>
>

-- 
----------------------------------------
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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