[patch] Get rid of inner-loop call to bfd_octets_per_byte in objdump

[patch] Get rid of inner-loop call to bfd_octets_per_byte in objdump

[Cary Coutant]

While profiling objdump, I found a call to bfd_octets_per_byte from
find_symbol_for_address, which seems wasteful given that the value is
already available in the info structure. Calling bfd_octets_per_byte
resuls in a call to bfd_lookup_arch for just about every line of
disassembly, which can be expensive especially if multiple targets are
enabled. This simple change cut 40% off the time it took to do an
objdump -d of a large binary when configured with
--enable-targets=all. (Of course, the savings will be substantially
less with only one or two targets enabled, but I still observed ~4%
improvement with just 2 targets -- i386 and x86 -- enabled.)

OK?

-cary


        * objdump.c (find_symbol_for_address): Avoid costly call to
        bfd_octets_per_byte.


Index: objdump.c
===================================================================
RCS file: /cvs/src/src/binutils/objdump.c,v
retrieving revision 1.162
diff -u -p -r1.162 objdump.c
--- objdump.c	27 Jul 2009 17:08:03 -0000	1.162
+++ objdump.c	21 Aug 2009 23:15:26 -0000
@@ -747,7 +747,7 @@ find_symbol_for_address (bfd_vma vma,
   aux = (struct objdump_disasm_info *) info->application_data;
   abfd = aux->abfd;
   sec = aux->sec;
-  opb = bfd_octets_per_byte (abfd);
+  opb = info->octets_per_byte;

   /* Perform a binary search looking for the closest symbol to the
      required value.  We are searching the range (min, max].  */

Re: [patch] Get rid of inner-loop call to bfd_octets_per_byte in objdump

[Alan Modra]

On Fri, Aug 21, 2009 at 04:34:26PM -0700, Cary Coutant wrote:
>         * objdump.c (find_symbol_for_address): Avoid costly call to
>         bfd_octets_per_byte.

OK.

-- 
Alan Modra
Australia Development Lab, IBM