[Libunwind-devel] Libunwind support for CFI from .debug_frame in DWARF

[Corey Ashford]

Hi all,

The dwarf-based unwinding in libunwind appears to rely only on the 
.eh_frame sections in the dwarf.  .eh_frame sections are not present 
when using C without one of -fexceptions, -funwind-tables, or 
-fasynchronous-unwind-tables.

.debug frames are present whenever the -g switch is used, and the CFI 
contained in these sections is very similar to what is in the .eh_frame 
sections.  At least it is for PowerPC.

Are there any plans to add support to libunwind for the case when only 
.debug_frame sections are present?

I ask this knowing that the default switches for building Linux these 
days includes -fexceptions, however many user apps will not have this 
switch set.

---

As an aside, for the Frysk developers out there:

Is there some reliance on the -fasynchronous-unwind-tables switch being 
used to compile the app-under-test besides getting libunwind to work? 
In other words, are there other parts of Frysk that rely on .eh_frame 
sections?

Thanks for your consideration,

- Corey



--
Corey Ashford
Software Engineer
IBM Linux Technology Center, Linux Toolchain
Beaverton, OR
503-578-3507
address@hidden