Re: some question about output section

[loody <miloody at gmail dot com>]

hi
2011/5/11 Alan Modra <amodra@gmail.com>:
> On Wed, May 11, 2011 at 02:27:09PM +0800, loody wrote:
>> 2. I found if the LMA of 2 sections are quite close, the size of
>> objcopy will get small, script1.
>> But why if the LMA of third section is close to previous section, the
>> size will still get big, script2?
>
> Why do you think the LMAs are close?
>
> Your scripts are setting LMA of a section to the end VMA of the
> previous section. ?I suspect that wasn't what you intended.
> See ld.info LOADADDR and SIZEOF.
>

I finally figured out what you mean :)

I use MEMORY command in my ld script, and I found the LMA of one
section will right behind previous one, even I didn't tell the script
to do so.

below is some part of my ld script:
MEMORY
{
        region0 : org = 0xbfc00000, l = 24k
        region1 : org = 0xbfc06000, l = 26k
        region2 : org = 0xbfb04000, l = 14k
        region3 : org = 0x80000000, l = 64k
}
....
.onlyText :  {        lib1.a:*.o (*.text)        _eonlytext =
ABSOLUTE(.);  } >region2 AT>region0

  . = ALIGN(4);
  _fbss = .;
  .sbss :   {    *(.sbss)    *(.scommon)    *(.bss)    *(COMMON)  } >region2

...


Below is the output of map:
.sbss           0x00000000bfb05540       0x60 load address 0x00000000bfc0187c
 *(.sbss)
 *(.scommon)
 .scommon       0x00000000bfb05540        0x4 main.o


It seem ".sbss" adopt the same setting of .onlyText even I didn't at
AT>region0 at the end.

appreciate your help,
miloody