Re: dwarf2 EH address size

[Ian Lance Taylor <iant at google dot com>]

DJ Delorie <dj@redhat.com> writes:

> > The EH code does seem to use POINTER_SIZE pretty consistently.
> > DWARF2_ADDR_SIZE is for the debug info, not the exception frame
> > info.  I haven't looked into the history of why this is so.
> 
> Hmmm... I suppose the EH info is used by the runtime as well, right?
> So changing to a non-standard addr size complicates the unwinder.

Certainly if you use DW_EH_PE_absptr the compiler, the unwinder
library, and the binutils all must agree on the size that that means.
On the other hand, if you define ASM_PREFERRED_EH_DATA_FORMAT the
encoding will be recorded in the FDE and CIE, and there will be no
possible confusion by any tool.  I actually think that is normally the
best choice, especially for a target for which confusion is possible.
Lots of targets define ASM_PREFERRED_EH_DATA_FORMAT, it's not unusual.

Ian