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RE: _GLOBAL_$F$


>-----Original Message-----
>From: Nik Ilijic [mailto:niki@pacomsystems.com]
>Sent: 19 October 2001 07:01

>What are these _GLOBAL_$F$'s and how do I get rid of them to reduce my
>code/data size so that it fits into the rom & ram.

  Dunno for absolute sure what they are, but a quick browse through the
gcc source reveals they are generated by the module dwarf2out.c in a 
subroutine called output_call_frame_info, which begins with this comment:

/* Output the call frame information used to used to record information
   that relates to calculating the frame pointer, and records the
   location of saved registers.  */

  It's some kind of stack-unwinding information related to dwarf-2 
exception handling.  I don't know how this stuff works, but looking at
what the code does that generates it, it seems very much like debug info,
which is also bloated and unwieldy.  As far as reducing it in size, I 
don't know, try and find someone who understands this stuff, but it might
be worth seeing if any of the exception-related -f flags can help - maybe
you can use exceptions based on setjmp-longjmp rather than dwarf2 frame
unwinding, maybe that would give you problems with destructors not being
called - I'm out of my depth here!

     DaveK
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