Re: Shared library annoyance with gcc-3_0-branch

[Geert Bosch <bosch at gnat dot com>]

On Tue, 20 Feb 2001 dewar@gnat.com wrote:

|<<Yes.  There must be exactly one copy of the exception handling
|routines in use within a program.
|>>
|
|Why is this the case? It sounds a bit suspicious (in particular, one
|wonders how this can be true, and yet exceptions work fine in a 
|multi-threaded environment).

RTH means that only one copy of the code and data must be linked in.
This has nothing to do with multithreading.

This restriction is unfortunate though, since it never was the case that 
the gcc library had such state, so it was perfectly fine to have multiple 
copies.  I really think we should have moved the exception stuff into a 
separate library.

Another issue is that calls to dynamically linked library routines
are relatively expensive on some platforms and this is a problem for
targets where we use libgcc for some 64-bit operations. These are
simple subprograms and having expensive calls to them may slow them
down for no good reason.

  -Geert