DWARF2 unwinding documentation/help

[Jim Wilson]

Bernardo Innocenti wrote:
> My target is an m68k-elf variant using a surrogate of the ELF format.
> It needs to place the unwinding tables in the data segment and doesn't
> link crtbegin/crtend. I've seen EH related stuff in there, but I'm
> not sure whether they are needed.

There needs to be a way for the unwinder to find the EH info at run 
time.  One mechanism involves using the crtbegin and crtend files to 
defines constructors and destructors that call register_frame_info and 
deregister_frame_info.  We can then maintain a linked list of pointers 
to EH info that can be searched at run time.  See unwind-dw2-fde.c. 
Another mechanism involves searching the in-core ELF headers at the time 
an exception is thrown.  We have glibc support for this, see 
unwind-dw2-fde-glibc.c.  There is also a darwin specific file I haven't 
looked at.  You will need to use one of these mechanisms, or define one 
that works for your target.
-- 
Jim Wilson, GNU Tools Support, http://www.SpecifixInc.com