From: Jason Merrill <jason@cygnus.com>
To: Horst von Brand <vonbrand@inf.utfsm.cl>, egcs@cygnus.com
Subject: Re: increase in object code size
Date: Tue, 23 Sep 1997 18:21:00 -0000 [thread overview]
Message-ID: <u93emva4mz.fsf@yorick.cygnus.com> (raw)
In-Reply-To: <199709232337.TAA00381@pincoya.inf.utfsm.cl>
>>>>> Horst von Brand <vonbrand@inf.utfsm.cl> writes:
> Jason Merrill <jason@cygnus.com> said:
>> This bloat can be significantly reduced by potential optimizations in the
>> assembler. [...]
> Nice idea for C++/Ada!
> And how do we get rid of it completely for the portable assembler, aka C?
With this mechanism, we can't eliminate it and still support throwing
through C code. Without the unwind info, the EH runtime doesn't know how
to unwind stack frames. The setjmp/longjmp code avoids this problem by
recording the necessary state, which significantly slows down C++ code that
doesn't throw.
SGI also uses the dwarf2 info, but reads it out of the executable as
needed. OSF/1 uses static data generated by the assembler, which I assume
is smaller and less general than the dwarf2 info; Richard tells me it
requires the prologue to be a precise sequence of instructions.
It's a difficult tradeoff.
Jason
next parent reply other threads:[~1997-09-23 18:21 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <199709232337.TAA00381@pincoya.inf.utfsm.cl>
1997-09-23 18:21 ` Jason Merrill [this message]
1997-09-24 7:13 ` Horst von Brand
1997-09-24 9:46 Mike Stump
-- strict thread matches above, loose matches on Subject: below --
1997-09-23 19:09 Mike Stump
1997-09-23 21:29 ` Joe Buck
[not found] <199709231643.KAA27118@harmony.village.org>
1997-09-23 10:05 ` Thomas Koenig
1997-09-23 7:21 Thomas Koenig
1997-09-23 9:32 ` Joe Buck
1997-09-23 10:03 ` John Carr
1997-09-23 10:16 ` Joe Buck
[not found] ` <199709231716.KAA13154.cygnus.egcs@atrus.synopsys.com>
1997-09-23 10:34 ` Jason Merrill
1997-09-23 10:38 ` Joe Buck
1997-09-23 10:56 ` Thomas Koenig
1997-09-24 1:58 ` Jakub Jelinek
[not found] ` <199709231755.TAA00725.cygnus.egcs@mvmap66.ciw.uni-karlsruhe.de>
1997-09-23 11:23 ` Jason Merrill
1997-09-24 2:33 ` Torbjorn Lindgren
1997-09-23 11:45 ` John Carr
1997-09-23 17:03 ` Richard Henderson
1997-09-23 17:16 ` Joe Buck
1997-09-28 14:43 ` Joern Rennecke
[not found] ` <199709240001.RAA05779.cygnus.egcs@dot.cygnus.com>
1997-09-23 18:25 ` Jason Merrill
1997-09-23 22:08 ` Richard Henderson
1997-09-23 22:46 ` Jason Merrill
1997-09-23 22:56 ` David S. Miller
1997-09-24 0:11 ` Richard Henderson
[not found] ` <199709231845.OAA14441.cygnus.egcs@biohazard-cafe.MIT.EDU>
1997-09-23 18:32 ` Jason Merrill
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