Re: Library tripled in size with GCC 4.2
Re: Library tripled in size with GCC 4.2
- Subject: Re: Library tripled in size with GCC 4.2
- From: Eric Gorr <email@hidden>
- Date: Thu, 16 Oct 2008 17:46:59 -0400
Done.
rdar://6297976
On Oct 16, 2008, at 4:37 PM, Jim Ingham wrote:
Can you file a bug on "gcc debug info"/X with the .o files from the
4.0 & 4.2 builds that you gave stats for below? Somebody on the
compiler team might want to see whether we're actually getting more
useful information for that much more DWARF...
Jim
On Oct 16, 2008, at 11:50 AM, Eric Gorr wrote:
Thanks for the tip on the dwarfdump tool.
In any case,
***** GCC 4.0----
File symtab strtab code data
DWARF debug STABS debug other file
--------- ----------------- ----------------- -----------------
----------------- ----------------- -----------------
---------------------------------------
5668480 130848 2.31% 398771 7.03% 1291665 22.79%
2290732 40.41% 0 0.00% 1556464 27.46% UCallBack.o
(i386)
***** GCC 4.2----
File symtab strtab code data
DWARF debug STABS debug other file
--------- ----------------- ----------------- -----------------
----------------- ----------------- -----------------
---------------------------------------
7751376 130428 1.68% 396885 5.12% 1266307 16.34%
4274182 55.14% 0 0.00% 1683574 21.72% UCallBack.o
(i386)
The DWARF Debug part doubled. This would seem to be definitive on
the question concerning whether or not the debug info is the culprit.
On Oct 16, 2008, at 1:05 PM, Jim Ingham wrote:
You can verify whether the DWARF debug information is really the
problem pretty easily before you go much further down this route.
Probably simplest to just look at individual .o files before they
get built into the library. So pick a big one - or one that shows
the most difference between gcc 4.0 & gcc 4.2, and do:
gdbrulez:tot-clean/build/gdb > dwarfdump --file-stats main.o
File symtab strtab code data
DWARF debug STABS debug other file
--------- ----------------- ----------------- -----------------
----------------- ----------------- -----------------
---------------------------------------
39580 1404 3.55% 1649 4.17% 10507 26.55%
14399 36.38% 0 0.00% 11621 29.36% main.o (i386)
on the two versions. What do you find?
Jim
On Oct 15, 2008, at 2:46 PM, Eric Gorr wrote:
So, is there some flag I can set to get the size of the library
down?
The flags I found were:
-feliminate-dwarf2-dups
However, this flag generated a bunch of the following errors:
{standard input}:50796:Expected comma after segment-name
{standard input}:50796:Rest of line ignored. 1st junk character
valued 32 ( ).
-feliminate-unused-debug-types
This flag didn't seem to affect the size of the library at all.
-glevel
I cannot go down to level 1 because of the information that would
not be included.
I cannot go up to level 3 because that would appear to just make
the library bigger.
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