On 18/08/16 07:00, Sandra Loosemore wrote:
> On 08/11/2016 04:31 AM, Thomas Preudhomme wrote:
>
>> diff --git a/gcc/doc/fragments.texi b/gcc/doc/fragments.texi
>> index
>> b6d8541c8ca820fa732363a05221e2cd4d1251c2..abf4e128671bb4751d21f24bb69625593d3c839e
>> 100644
>> --- a/gcc/doc/fragments.texi
>> +++ b/gcc/doc/fragments.texi
>> @@ -117,12 +117,15 @@ specified, there are combinations that should
>> not be built. In that
>> case, set @code{MULTILIB_EXCEPTIONS} to be all of the switch exceptions
>> in shell case syntax that should not be built.
>>
>> -For example the ARM processor cannot execute both hardware floating
>> -point instructions and the reduced size THUMB instructions at the same
>> -time, so there is no need to build libraries with both of these
>> -options enabled. Therefore @code{MULTILIB_EXCEPTIONS} is set to:
>> +For example on ARM targets @option{-mfloat-abi=soft} requests to use a
>> +softfloat implementation for floating-point operations. Therefore, it
>> +does not make sense to find both @option{-mfloat-abi=soft} and an
>> +@option{mfpu} option on the command line so @code{MULTILIB_EXCEPTIONS}
>> +could contain the following exception (assuming that
>> +@option{-mfloat-abi} comes after in @code{MULTILIB_OPTIONS} and given
>> +that @option{-mfloat-abi=soft} is the default value):
>> @smallexample
>> -*mthumb/*mhard-float*
>> +*mfpu=*
>> @end smallexample
>>
>> @findex MULTILIB_REQUIRED
>
> This version still has a lot of copy-editing issues. I suggest
> rewriting as:
>
> For example, on ARM targets @option{-mfloat-abi=soft} requests use of
> software floating-point operations, so it
> does not make sense to build libraries with both
> @option{-mfloat-abi=soft} and an @option{-mfpu} option.
> @code{MULTILIB_EXCEPTIONS} could contain the following exception
>
> but here I get stuck in suggesting a rewrite, because I can't parse this
> part at all to figure out what you're trying to say:
>
> (assuming that
> @option{-mfloat-abi} comes after in @code{MULTILIB_OPTIONS} and given
> that @option{-mfloat-abi=soft} is the default value):
>
> "comes after in"? Comes after what? If the order is important here,
> the documentation should explain why instead of just "assuming" things
> about it.
>
> -Sandra the confused
>
I think it's probably best to just drop the entire parenthetical
subcluase. This is documentation of how to use MULTILIB_EXCEPTIONS not
precise documentation on what needs to be done on ARM.
In fact, it might be better to just rewrite the whole section based on a
theoretical machine that has two ISAs, one which can support
floating-point and one which can't. You then get back to essentially
the same text as we had originally but anonymised and future proofed.
R.
