Re: gas 2.16 and assembly macros -- entry_64.S build failure

From: H. Peter Anvin
Date: Mon Oct 04 2010 - 14:24:57 EST


On 10/04/2010 09:20 AM, Avi Kivity wrote:
> On 10/04/2010 05:43 PM, H. Peter Anvin wrote:
>> On 10/04/2010 03:04 AM, Avi Kivity wrote:
>>> On 10/01/2010 02:26 AM, H. Peter Anvin wrote:
>>>> ... but that doesn't work with the macros like movq_cfi. On those, we
>>>> could argue that at least people won't put $ on them, but cpp will still
>>>> split them apart with spaces; this apparently causes problems at least
>>>> as soon as there is an expression more complicated than addition
>>>> involved (apparently plus signs are okay, but minus signs aren't!)
>>>
>>> Likely due to the fact that a minus sign can later join with a number
>>> and become a new token, but a plug sign cannot.
>>>
>>
>> ... except the same thing applies to other operators, other than the
>> plus sign. This kind of characterization is insanely frustrating, and
>> really doesn't seem to follow logical rules ... we had a previous one
>> where changing a macro name from upper case to lower case made gas 2.16
>> work...
>>
>
> Well, / and * do join. % doesn't. In a way, + does.
>
> cpp is not a pure text processing language. It's specifically geared to
> C, and is fairly creaky when applying it to something other than C (and
> is only somewhat creaky when applying it to C).
>

The problem isn't with cpp, though, it's with gas. There are bugs in
the gas 2.16 macro features that don't apply to any other gas version,
before *or* after.

-hpa
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