Problem with objcopy

[Tim Cussins]

Hi Leon,

On Thu, 2009-06-25 at 14:26 +0300, Leon Pollak wrote:
> Hello, all.
> 
> 
> 
> Recently I made a small change in the following code:
> class cFoo {
> protected:
> uchar DataIn[MAX_DATA_LEN], DataOut[MAX_DATA_LEN];
> ..............
> };
> 
> 
> 
> 
> I changed MAX_DATA_LEN from 1000 to 300000.
> 
> 
> 
> 
> This resulted in 300000 growth of the BIN file which I produce by
> command:
> powerpc-rtems-objcopy -j .text -j .data -O binary app.elf app.bin
> 

surely you'd see 2x that growth - you've got 2 member variables that
depend on MAX_DATA_LEN...

> 
> 
> Looking into the map file I see that the real addition of 300000 bytes
> resides in the .bss section, which seems to me correct.
> So, why the size of binary file depends on .bss section size?!?!

without seeing your linker script, perhaps section .bss is listed in
front of .data, and it's pushing up the LMA of .data - this would appear
as a giant section of zeros in your binary image, and the binary size
increase you're talking about...

> I tried to play with -j and -R parameters, but all imaginable
> combinations gave nothing - the output file size was exactly the same.
> 

above explanation could account for this. AFAIK objcopy uses (quite
rightly) the LMA to position sections in the binary output.

> 
> 
> 
> Many thanks ahead for any help.
> -- 
> Leon 

Hope this provides some food for thought...
Tim