Re: [ECOS] arm-elf-gcc comprehension

[ANDRE Sébastien <sebastien.andre@sxb.bsf.alcatel.fr>]

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Hi again,

So i work on my problem !! but i see a strange thinks !!

When i make this command,
      arm-elf-gcc  -c test.c -ggdb -Wall

Normally it generate a "test.o" object file !!! but by hazardous way i see that it's already an elf
executable file

I test it with  "arm-elf-size test.o"
>>   text    data     bss     dec     hex filename
>>     84       0       0      84      54 test.o

and with "arm-elf-readelf -S test.o"
>> Section Headers:
>>   [Nr] Name              Type            Addr     Off    Size   ES Flg Lk Inf Al
>>  [ 0]                   NULL            00000000 000000 000000 00       0   0 0
 >> [ 1] .text             PROGBITS        00000000 000034 000054 00  AX   0   0 4
>>  [ 2] .rel.text         REL             00000000 00064c 000028 08      15   1 4
>>  [ 3] .data             PROGBITS        00000000 000088 000000 00  WA   0   0 1
 >> [ 4] .bss              NOBITS          00000000 000088 000000 00  WA   0   0 1
 >> [ 5] .debug_abbrev     PROGBITS        00000000 000088 000045 00       0   0 1
 >> [ 6] .debug_info       PROGBITS        00000000 0000cd 00007b 00       0   0 1
 >> [ 7] .rel.debug_info   REL             00000000 000674 000030 08      15   6 4
 >> [ 8] .debug_line       PROGBITS        00000000 000148 000066 00       0   0 1
 >> [ 9] .rel.debug_line   REL             00000000 0006a4 000040 08      15   8 4
 >> [10] .debug_pubnames   PROGBITS        00000000 0001ae 00001b 00       0   0 1
  >>[11] .rel.debug_pubnam REL             00000000 0006e4 000008 08      15   a 4
 >> [12] .debug_aranges    PROGBITS        00000000 0001c9 000020 00       0   0 1
 >> [13] .rel.debug_arange REL             00000000 0006ec 000010 08      15   c 4
 >> [14] .shstrtab         STRTAB          00000000 0001e9 0000c2 00       0   0 1
 >> [15] .symtab           SYMTAB          00000000 000554 0000d0 10      16   b 4
  >>[16] .strtab           STRTAB          00000000 000624 000027 00       0   0 1

and i can simulate it on arm-elf-gdb !!!

WHAT IS HAPPENED !!!??? Why it's an elf-executable ? and not an object file ???

best regards,
Sébastien.



ANDRE Sébastien wrote:

> Hi all,
>
> So i try a test with "arm-elf-gdb" and "arm-elf-gcc" !!
>
> Typically i write a basycally C program like it
>
> int main()
> {      int a;
>        while (a < 5000)
>        {  a++ ; }
>        return a;
> }
>
> ==> a program without stdlib, stdio, etc ..... :-)
>
> So i want to compile and build it for arm processor but NOT for eCos Kernel !!
> I want only arm executable file (it possible normally ?)
>
> and after my idea is to try to simulate it on gdb (normally it's possible now because no really hardware
> dependant exept arm core ! ?)
> If i'm wrong somewhere again !! say me it !
>
> So i build around like it :
>     arm-elf-gcc -c test.c -o test.o -ggdb -Wall
>     arm-elf-gcc -Wl,--gc-sections -o test test.o -nostdlib
>
> PS: i try without  "-Wl,--gcc-sections" but if i suppress it i have an error build process like it :
>         test.o: In function `main':
>         /root/test/test.c:4: undefined reference to `__gccmain'
>         collect2: ld returned 1 exit status
>
> An executalble file is generate ..... but i have two mistake (in reallity only one i think)
>
> If i try to simulate it (debug) on gdb with this procedure
> arm-elf-gdb test
>    > target sim
>    > load
>
> i have this error :
>     gdbsim: no loadable sections "/root/test/test"
>      unable to load program
>
> So now for see if i have some sections i launch this command :
>       arm-elf-size test
> and say it :
>
> text    data     bss     dec     hex filename
>       0       0       0       0       0 test
>
> So what i miss for build correctly my elf executable files ?
>
> So i know that isn't really an eCos problem but i thanks you if somebody can help me..
>
> bestregards,
> Sébastien.