I'm working with a target that has a call instruction
similar to SPARC: the address of the calling instruction
is saved in a link register (lr). The actual return address
is, like SPARC, lr+8.
It seemed to me that the right thing would be to have the
initial value of the "return address" column in the CIE
contain the location expression for lr+8. When I tried this,
the offset was ignored and only the register number was generated.
I came across this comment in dwarf2out.c:
case PLUS:
/* The return address is at some offset from any value we can
actually load. For instance, on the SPARC it is in %i7+8. Just
ignore the offset for now; it doesn't matter for unwinding frames. */
When I looked at what sparc-gcc was generating for the return
address column, I discovered that it didn't generate anything.
Instead, sparc-gdb ignores it and computes %i7+8.
It seems to me that the offset is necessary to unwind a frame
correctly (at least, if you use the CIE info). Is there any
reason to discard it?
--
Michael Eager [EMAIL PROTECTED]
1960 Park Blvd., Palo Alto, CA 94306 650-325-8077
