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Re: Expansion of __builtin_frame_address
Daniel Jacobowitz wrote:
> On Sun, Jun 04, 2006 at 10:29:14AM -0700, Mark Mitchell wrote:
>> Daniel Jacobowitz wrote:
>>> On Sun, Jun 04, 2006 at 09:54:25AM -0700, Mark Mitchell wrote:
>>>> Richard E. asked what possible uses this function might have.
>>>> Obviously, GLIBC's backtrace() function is one, though I guess that's a
>>>> weak example, in that we all agree one should really be using unwind
>>>> information.
>>> Which there is no plausible way to do for the ARM EABI, due to ARM's
>>> other choices.
>> If one compiled everything with -fexceptions, could you then use the ARM
>> ABI EH unwind stuff? Or, is there just no way to do this in the ARM EABI?
>
> The DWARF unwinding tables are descriptive; you can interpret them
> however necessary, for unwinding or for backtraces. But the ARM
> unwinding tables are more opaque.
In that case, I guess the only open question is whether _b_f_a(0) has a
sensible GCC-specific meaning, or whether we should just declare it
invalid/undefined on ARM.
Thanks,
--
Mark Mitchell
CodeSourcery
mark@codesourcery.com
(650) 331-3385 x713