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Long link times and elf_bfd_discard_stabs

Jamie Guinan guinan@bluebutton.com
Mon Oct 27 23:42:00 GMT 2003 
Hi,

I'm working on a project using mostly C++ which taking a very long
time to link, using mips-elf-ld from binutils-2.13.

My host platform is Linux 2.4.22, so I was able to use oprofile,
and easily find what's taking so much time:

vma      samples  %           symbol name
08087384 21440225 81.8378     _bfd_elf32_reloc_symbol_deleted_p
080503ec 3260410  12.4451     print_one_symbol
080642d8 412356    1.5740     bfd_hash_traverse
0804e914 190403    0.7268     lang_output_section_find

The "deleting discardable stabs" patch was added almost 2 years ago,

  http://sources.redhat.com/ml/binutils/2001-11/msg00305.html

My questions:

It looks like it is just trying to mop up unused debugging symbols, is
that right?  

Are they harmless if I leave them in there?  

In that case, can I safely disable this by going back to
${LDEMUL_FINISH-NULL} in elf32.em?

When I do this, my link time drops from 90 seconds to 4 seconds on 
a 3GHz P4.

Details (fwiw): the project is about 700 C++ modules, cross-compiled
with mips-elf-gcc 3.2.3, and most if it is partially linked (-r)
before the final link.

Thanks,
-Jamie
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