arm-linux-gnueabihf: gcc and ld problem with --sysroot option

The TI C/C++ Compiler forum is primarily about TI compilers, though we are starting to cover the Linaro gcc ARM compiler which ships with CCS.  Unfortunately, that is not the ARM compiler you are using.

Since they are both gcc compilers I looked into it anyway.  I used the Linaro compiler as a proxy for yours.  I cannot reproduce your issue.  According to the documentation on --sysroot I found, both forms should work equally well at finding libraries (but not header files).  That -Wl,--sysroot fails to find your libraries is something I cannot explain.

Thus, I am moving this thread to the Sitara ARM processors forum.

Thanks and regards,

-George

Sorry for posting in the wrong place...

So, let me be really specific then. Since my helloworld program shows this issue, maybe it will be easier to reproduce it if I show all the steps. The only thing I changed from the SDK's installation is where the folder linux-devkit is located: I placed it in the /opt/ directory·

Helloworld.c:

#include <stdio.h>
#include <stdlib.h>

int main(void)
{
 printf("\nHello, world!\n\n");

 return EXIT_SUCCESS;

}

Jumping to the command line:

$ export PATH=/opt/linux-devkit/sysroots/i686-arago-linux/usr/bin/:$PATH

$ arm-linux-gnueabihf-gcc -c -march=armv7-a -marm -mthumb-interwork -mfloat-abi=hard -mfpu=neon -mtune=cortex-a8 --sysroot=/opt/linux-devkit/sysroots/armv7ahf-vfp-neon-3.2-oe-linux-gnueabi -Wall -Wextra -Wmissing-prototypes -Wstrict-prototypes -fomit-frame-pointer -g0 -O2 helloworld.c -o helloworld.o

$ arm-linux-gnueabihf-gcc -Wl,--sysroot=/opt/linux-devkit/sysroots/armv7ahf-vfp-neon-3.2-oe-linux-gnueabi -o helloworld helloworld.o
/opt/linux-devkit/sysroots/i686-arago-linux/usr/bin/../lib/gcc/arm-linux-gnueabihf/4.7.3/../../../../arm-linux-gnueabihf/bin/ld: cannot find crt1.o: No such file or directory
/opt/linux-devkit/sysroots/i686-arago-linux/usr/bin/../lib/gcc/arm-linux-gnueabihf/4.7.3/../../../../arm-linux-gnueabihf/bin/ld: cannot find crti.o: No such file or directory
collect2: error: ld returned 1 exit status

$ arm-linux-gnueabihf-gcc --sysroot=/opt/linux-devkit/sysroots/armv7ahf-vfp-neon-3.2-oe-linux-gnueabi -o helloworld helloworld.o (this one works)

So, there is a couple things to say: I copied the CFLAGS used in the environment setup file (in my case it is located in /opt/linux-devkit/environment-setup), hence some of the options besides -c the first time I call the gcc. The other thing is that I thought it would be simpler to show the commands instead of the Makefile file I use -- I know the -c option could be left out here.

Well, hope anyone else get this same behave! 

DAVI

I think I found out why -Wl isn't supporting the --sysroot option:

Previously, I didn't notice that there is another part to the help under the option --target-help when I said I tried the ---help of arm-linux-gnueabihf-gcc. When I type

$ arm-linux-gnueabihf-gcc --target-help

there is a section that list the linker options one can pass via -Wl and in this list there is no mention to --sysroot anywhere.

That means maybe the assumption that arm-linux-gnueabihf-gcc calls arm-linux-gnueabihf-ld passing everything in -Wl is wrong...

It would be very helpful if anyone could verify if that is the case, because --target-help is supposed to be target specific, would it make any sense to display all the -Wl option there?

Thanks!

DAVI

Obs: /opt/linux-devkit/sysroots/i686-arago-linux/usr/bin/../lib/gcc/arm-linux-gnueabihf/4.7.3/../../../../arm-linux-gnueabihf/bin/ld (the one showed in red in my example) and arm-linux-gnueabihf-ld are the same binary file...

Hi,

    Can you please mention the way i need to compile an C++ application using   arm-linux-gnueabihf-g++

guest@ubuntu:~$ arm-linux-gnueabihf-g++ --sysroot=/mnt/build/linux-devkit/sysroots/armv7ahf-vfp-neon-3.2-oe-linux-gnueabi hello.cpp

hello.cpp:1:19: fatal error: iostream: No such file or directory
compilation terminated.

You will have to change the paths I use, but here is a command that tricks the compiler into looking for the right folders...

$ arm-linux-gnueabihf-g++ -c -march=armv7-a -marm -mthumb-interwork -mfloat-abi=hard -mfpu=neon -mtune=cortex-a8 --sysroot=/opt/linux-devkit/sysroots/armv7ahf-vfp-neon-3.2-oe-linux-gnueabi -Wall -Wextra -fomit-frame-pointer -g0 -O2 -I/opt/linux-devkit/sysroots/armv7ahf-vfp-neon-3.2-oe-linux-gnueabi/include/c++/4.7.3 -I/opt/linux-devkit/sysroots/armv7ahf-vfp-neon-3.2-oe-linux-gnueabi/include/c++/4.7.3/arm-linux-gnueabihf/arm-linux-gnueabi/  a.cpp -o a.o

$ arm-linux-gnueabihf-g++ --sysroot=/opt/linux-devkit/sysroots/armv7ahf-vfp-neon-3.2-oe-linux-gnueabi -o a a.o

Et voilà. I really think this new compiler complicate things and there is no documentation so far. TI should at least compile a hello world example and post it on the wiki to help us...

DAVI

You will also have to change the filesystem you use (if you haven't done so yet). Use the one that comes with the new SDK, changing the GCC version forces you to recompile EVERYTHING...

So simple and I never thought into look for this. Thank you! :-)

DAVI