Currently GCC has to describe the CFA twice, once for the unwind info
and once in the form of location lists for DW_AT_frame_base. This
dwarf3 opcode allows DW_AT_frame_base to essentially reference the
unwind info definition.
What is the simplest way to test a patch implementing this?
We'll whip up a patch to generate the opcode, then ...
Probably to watch the value of a function argument on
the stack, while stepping through the prologue of a function.
I have a gdb patch; attach the gcc patch here and I will give it a try.
Created attachment 3979 [details]
quick hack to make gcc generate DW_OP_call_frame_cfa
I'm not sure off-hand what conditional I should really be using,
but no conditional at all will work for testing. =)
I checked in the fix.