Debugging frameless code

Daniel Berlin
Sat Sep 30 11:23:00 GMT 2000

> I haven't tried frameless functions for ARM (and certainly not for
> THUMB).  However, I did commit the following change recently which
> does help gdb better deal with optimized code (the arm_scan_prologue
> bit):

I can answer this question authoritatively. By default, on all platforms
but MIPS, gcc is not generating the information needed to get stack
backtraces in all cases, when we have no frame pointer. GCC *can* generate
the info, it's just only told to on MIPS. I've turned it on to play with
on BeOS, by #defining DWARF2_UNWIND_INFO in the beos-elf.h file in GCC,
and recompiling GCC.

However, GDB currently won't use this info in any case.
I've been reworking the dwarf2 reader, and i can add support for reading
the info, and even evaluating it, but we wouldn't be able to do anything
with it, without
modifying other parts of gdb to see if we were using dwarf2, and if we had
the call frame info, use it.

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