Re: [PATCH v2 2/2] Correct invalid assumptions made by (mostly) DWARF-2 tests

Doug Evans
2014-11-16T21:52:04Z

On Sun, Nov 16, 2014 at 12:05 PM, Maciej W. Rozycki
<macro@codesourcery.com> wrote:
> On Sun, 16 Nov 2014, Doug Evans wrote:
>
>> >>> Index: gdb-fsf-trunk-quilt/gdb/testsuite/gdb.dwarf2/dw2-canonicalize-type.S
>> >>> ===================================================================
>> >>> ---
>> >>> gdb-fsf-trunk-quilt.orig/gdb/testsuite/gdb.dwarf2/dw2-canonicalize-type.S
>> >>> 2014-10-02 07:56:23.000000000 +0100
>> >>> +++
>> >>> gdb-fsf-trunk-quilt/gdb/testsuite/gdb.dwarf2/dw2-canonicalize-type.S
>> >>> 2014-10-02 07:58:10.978958268 +0100
>> >>> @@ -15,7 +15,8 @@
>> >>>
>> >>> .text
>> >>> .globl main
>> >>> -main: .byte 0
>> >>> +main:
>> >>> + .dc.l 0
>> >>
>> >> We've never used .dl.l before, and I don't know how widely available
>> >> it is (in fact, I couldn't find it in the GAS manual). How about using
>> >> .word or .4byte? It would also be consistent with what we've usually be
>> >> using. Would that work?
>> >
>> > Agreed.
>>
>> Sorry for the followup, but FAOD, .4byte.
>> .word may be a different size on some platforms.
>
> If anything, that would have to be `.4byte'.
>
> I chose `.dc.l' because it is the only fully portable GAS pseudo-op to
> produce 32-bit data output. Testing portability was the actual reason
> to add all the `.dc.*' pseudo-ops to GAS. As you've already observed
> `.word' is unportable, and neither is `.4byte' as the latter is only
> supported for ELF targets. However in DWARF-2 testing we're probably on
> an ELF target anyway.

Yeah. We've been using .4byte for portability in gdb.dwarf2 as long
as I can remember.

I didn't know about .dc.l, but there's nothing in the name that screams
"portability" to me. In fact, I can imagine it causing at least a few
people to have
to spend time looking it up just to verify it's OK to use (whereas
they'd be less
inclined to with ".4byte"). Not good.

> So I'll update the tests to use `.4byte'. Thanks for your review.

Cool. I've got one more review coming.