Re: [RFC] Improve amd64 prologue analysis

Kai Tietz
2010-11-25T19:19:26Z

2010/11/25 Joel Brobecker <brobecker@adacore.com>:
>> > One last bit of information - which I got second hand, but hopefully
>> > accurate. I think that the GCC team is on its way to generating the
>> > unwinding info in that format, rather than the usual DWARF-based
>> > eh_frame/debug_frame. So the Microsoft format should become the default
>> > even for code generated by GCC... So eventually, I think we are going
>> > to need to add an unwinder for that, even for GCC code.
>>
>> I certainly hope you're wrong here, since it would mean a massive ABI
>> break on platforms currently using .eh_frame, and presumably would be
>> x86-specific.
>
> I should have said that this is only relevant to x86_64-windows.
> All other platforms will continue to use the usual eh_frame, of
> course.
>
> --
> Joel
>

Well, Joel is right. Beginning with 4.6 gcc there is a base support of
SEH prologue unwind information for x64 windows target. By this it is
possible to use API provided by imagehlp.dll for generating stack
backtraces. At the moment SEH isn't used for exception unwinding, but
this is planned for 4.7 gcc version. A test-implementation of it is
already existing, but not sure if it will make it into 4.6 as optional
unwind implementation for tests.

Kai