Re: [patch/mips, rfc] Don't define FP_REGNUM

Andrew Cagney
2002-09-17T21:20:53Z

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Thanks for eyeballing this.

> For the MIPS to work, a custom virtual_frame_pointer() function would be
>> needed. I don't see any point in implementing this, though, as there is
>> no tracepoint target to test it against. Anyway, coments on this aspect
>> of the patch? If not, I'll check it in.
>>
>> [Hmm, need to mention this in the NEWS file. The MIPS $fp will finally
>> behave as specified in the documentation.]
>
>
> Looks good to me. And there may someday be a tracepoint target to
> test it against - I hope to add tracepoints to gdbserver, eventually.
> When that happens I can revisit this.

I've so far checked in the attached...

Andrew

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2002-09-17 Andrew Cagney <ac131313@redhat.com>

* arch-utils.c (legacy_virtual_frame_pointer): If FP_REGNUM is
invalid, return SP_REGNUM.

Index: arch-utils.c
===================================================================
RCS file: /cvs/src/src/gdb/arch-utils.c,v
retrieving revision 1.68
diff -u -r1.68 arch-utils.c
--- arch-utils.c 14 Sep 2002 09:40:36 -0000 1.68
+++ arch-utils.c 17 Sep 2002 21:17:58 -0000
@@ -423,8 +423,19 @@
int *frame_regnum,
LONGEST *frame_offset)
{
- gdb_assert (FP_REGNUM >= 0);
- *frame_regnum = FP_REGNUM;
+ /* FIXME: cagney/2002-09-13: This code is used when identifying the
+ frame pointer of the current PC. It is assuming that a single
+ register and an offset can determine this. I think it should
+ instead generate a byte code expression as that would work better
+ with things like Dwarf2's CFI. */
+ if (FP_REGNUM >= 0 && FP_REGNUM < NUM_REGS)
+ *frame_regnum = FP_REGNUM;
+ else if (SP_REGNUM >= 0 && SP_REGNUM < NUM_REGS)
+ *frame_regnum = SP_REGNUM;
+ else
+ /* Should this be an internal error? I guess so, it is reflecting
+ an architectural limitation in the current design. */
+ internal_error (__FILE__, __LINE__, "No virtual frame pointer available");
*frame_offset = 0;
}