[Bug libstdc++/64535] Emergency buffer for exception allocation too small

["rguenth at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64535

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
  Attachment #34399|0                           |1
        is obsolete|                            |
             Status|UNCONFIRMED                 |ASSIGNED
   Last reconfirmed|                            |2015-01-12
           Assignee|unassigned at gcc dot gnu.org      |rguenth at gcc dot gnu.org
     Ever confirmed|0                           |1

--- Comment #8 from Richard Biener <rguenth at gcc dot gnu.org> ---
Created attachment 34418
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=34418&action=edit
prototype of a variable-size emergency allocator

The attached patch implements a new fixed-size arena, variable size object
allocator and uses it for the emergency pool (not yet for the dependent
exception allocations, but trivial to change those).

I welcome libstdc++ coding style issues pointed out and general comments
on whether this approach is fine (also unifying the dependent allocations
in here).

TODO: implement free-list sorting and merging of free-list entries

Sofar tested by forcing the use of the emergency allocator (as in the patch,
see #if 1) by bootstrapping and testing C++ (hopefully sorted out a last issue,
test re-running).