[Dwarf-Discuss] DWARF for DSP like processors with multiple memories

Daniel Jacobowitz drow at false.org
Tue Nov 25 10:14:10 PST 2008


On Tue, Nov 25, 2008 at 08:56:22AM -0800, Michael Eager wrote:
> I believe that GCC for PowerPC generates both DW_AT_frame_base and
> CFI which gives partial register save info.  DW_AT_frame_base is used
> to access args and local variables, if I recall correctly.

Right.  I believe there was a discussion at some point about
referencing the frame base from the CFI or vice versa, but I don't
think anything came of it.

> Some implementations (like GCC-powerpc) only
> provide the minimum needed to unwind, leaving the ABI (or guesswork)
> to know where specific registers have been saved on the stack.

I don't believe that's correct.  GCC does have a known omission (it's
not accurate in epilogue sequences), and a known quirk (call-clobbered
registers are not explicitly marked), but it should describe every saved
register.

-- 
Daniel Jacobowitz
CodeSourcery



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