Linker question

Franck JULLIEN franck.jullien at gmail.com
Wed Dec 14 05:43:49 EST 2011


2011/12/14 Sascha Hauer <s.hauer at pengutronix.de>:
> Hi Franck,
>
> On Wed, Dec 14, 2011 at 12:14:08AM +0100, Franck JULLIEN wrote:
>> Hi,
>>
>> I'm doing some tests with the openrisc processor. As I'm building
>> barebox I have a question
>> related to the linking of barebox.
>>
>> In order to get uint64 arithmetic functions, I need to add "-L $(shell
>> dirname `$(CC) $(CFLAGS) -print-libgcc-file-name`) -lgcc"
>> to the final link (only way ? found this in uboot).
>>
>> However, if I do this using LDFLAGS_barebox I get :
>>
>> /opt/crosstool/or32/or32-elf/bin/or32-elf-ld  -Map barebox.map -L
>> /opt/crosstool/or32/or32-elf-1.0rc1/bin/../lib/gcc/or32-elf/4.5.1-or32-1.0rc4
>> -lgcc -o barebox -T arch/openrisc/cpu/barebox.lds  --start-group
>> common/built-in.o  drivers/built-in.o  commands/built-in.o
>> lib/built-in.o  crypto/built-in.o  net/built-in.o  fs/built-in.o
>> arch/openrisc/boards/generic/built-in.o  arch/openrisc/lib/built-in.o
>> arch/openrisc/cpu/built-in.o --end-group
>>
>> And it doesn't work. It works if "-L
>> /opt/crosstool/or32/or32-elf-1.0rc1/bin/../lib/gcc/or32-elf/4.5.1-or32-1.0rc4
>> -lgcc" is at the end of the command line:
>>
>> /opt/crosstool/or32/or32-elf/bin/or32-elf-ld -Map barebox.map -o
>> barebox -T arch/openrisc/cpu/barebox.lds --start-group
>> common/built-in.o  drivers/built-in.o  commands/built-in.o
>> lib/built-in.o  crypto/built-in.o  net/built-in.o  fs/built-in.o
>> arch/openrisc/boards/generic/built-in.o  arch/openrisc/lib/built-in.o
>> arch/openrisc/cpu/built-in.o --end-group -L
>> /opt/crosstool/or32/or32-elf-1.0rc1/bin/../lib/gcc/or32-elf/4.5.1-or32-1.0rc4
>> -lgcc
>>
>> Any idea on why this is happening ?
>>
>> The only way I found to fix this is to move LDFLAGS_barebox in the
>> main Makefile:
>>
>> -      cmd_barebox__ ?= $(LD) $(LDFLAGS) $(LDFLAGS_barebox) -o $@ \
>> +      cmd_barebox__ ?= $(LD) $(LDFLAGS)  -o $@ \
>>        -T $(barebox-lds) $(barebox-head)                         \
>> -      --start-group $(barebox-common) --end-group                  \
>> +      --start-group $(barebox-common) --end-group $(LDFLAGS_barebox)
>>                \
>>        $(filter-out $(barebox-lds) $(barebox-common) FORCE ,$^)
>>
>> What do you think about this problem ?
>
> The kernel currently does it the same way for openrisc. The other
> architectures have there own implementation of the 64bit arithmetix
> functions inside the kernel (and barebox) which is IMO cleaner. Maybe
> you can grab them from the gcc source code and use them in barebox
> instead.
>
> Sascha
>
> --
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Ok thanks,

I'll see what I can do.



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