Re: Large size of C++ v3 libs

[<llewelly at dbritsch dot dsl dot xmission dot com>]

On Fri, 12 May 2000, H . J . Lu wrote:

> On Fri, May 12, 2000 at 02:16:12PM -0600, llewelly@dbritsch.dsl.xmission.com wrote:
> > On Fri, 12 May 2000, Ryszard Kabatek wrote:
> >
> > > I compiled the gcc (egcs-20000501) on Linux (SuSE 6.2) with
> > > --enable-libstdcxx-v3.
> > > The build was successfull, but the size of the libraries is really large:
> > > libstdc++.a       - 24584366 bytes,
> > > libstdc++.so.3.0.0 - 5718674 bytes.
> >
> > I believe the libraries are built with -g by default. Since they are
> >   experimental, and thus probably buggy, this is usually a good
> >   thing. However, it greatly increases the size of the binaries.
> >
> > If you decide to strip(1) them, be careful. On my i686-pc-linux-gnu, with
> >   binutils 2.9.5.0.41, I need to use 'strip --strip-debug foo.a' and *not*
> >   'strip --strip-unneeded foo.a'. The --strip-unneeded rips out the stack
> >   unwinding stuff needed for exceptions, which it seems to consider
> >   'unneeded'
>
> This sounds like a bug in strip. Could you please provide a small
> testcase? I'd like to fix it.
>
> Thanks.
>
>
> H.J.
>

Actually, it appears that I misunderstood what was going on.
  I had had some problems with stripped executables that contained
  exception throwing code. I had noticed that strip removed the
  '__EXCEPTION_TABLE__' and '__FRAME_BEGIN__' symbols, so I
  (incorrectly) assumed that was the cause of the problems.

It seems that the function containing the 'throw' is
  disappearing. 

I have a test case that (I think) shows a bug in strip, but it is not
  the bug I thought it was.

Here it is:  
        
{~/cc_exer}cat foo_vanish.h
void foo(int j);

extern int l;
{~/cc_exer}cat foo_vanish.cc

#include"foo_vanish.h"

int l=1;

void bar(int j)
  {
    throw j;
  }

void foo(int j)
  {
    bar(j);
  }

{~/cc_exer}cat foo_vanish_main.cc 

#include"foo_vanish.h"

int main()
  {
    int k=1;
    try
    {
      foo(k);
    }
    catch(int i)
    {
      return l;
    }
    return l;
  }
{~/cc_exer}g++ -g -Wall -c foo_vanish.cc 
{~/cc_exer}nm --demangle foo_vanish.o 
00000089 t Letext
00000000 ? __EXCEPTION_TABLE__
00000000 ? __FRAME_BEGIN__
         U __cp_push_exception
         U __eh_alloc
         U int type_info function
         U __throw
00000000 T bar(int)
0000006c T foo(int)
00000000 D l
         U terminate(void)
{~/cc_exer}strip --strip-unneeded foo_vanish.o
{~/cc_exer}nm --demangle foo_vanish.o 
         U __cp_push_exception
         U __eh_alloc
         U int type_info function
         U __throw
00000000 T bar(int)
         U terminate(void)
{~/cc_exer}g++ -g -Wall foo_vanish_main.cc foo_vanish.o
/tmp/cciCkDOS.o: In function `main':
/home/llewelly/cc_exer/foo_vanish_main.cc:9: undefined reference to `foo(int)'
/home/llewelly/cc_exer/foo_vanish_main.cc:15: undefined reference to `l'
/home/llewelly/cc_exer/foo_vanish_main.cc:13: undefined reference to `l'
collect2: ld returned 1 exit status
{~/cc_exer}strip -V
GNU strip 2.9.5
Copyright 1997, 98, 99, 2000 Free Software Foundation, Inc.
This program is free software; you may redistribute it under the terms of
the GNU General Public License.  This program has absolutely no warranty.
{~/cc_exer}ld -v
GNU ld version 2.9.5 (with BFD 2.9.5.0.41)
{~/cc_exer}g++ -v
Reading specs from /usr/lib/gcc-lib/i686-pc-linux-gnu/2.95.2/specs
gcc version 2.95.2 19991024 (release)

on i686-pc-linux-gnu .