RFR: 8149594 - Clean up Hotspot makefiles

[Kim Barrett]

> On Feb 10, 2016, at 7:51 PM, Jesper Wilhelmsson <jesper.wilhelmsson at oracle.com> wrote:
> Den 10/2/16 kl. 23:34, skrev Kim Barrett:
>> Den 10/2/16 kl. 21:31, skrev Jesper Wilhelmsson:
>>> https://bugs.openjdk.java.net/browse/JDK-8149594
>>> http://cr.openjdk.java.net/~jwilhelm/8149594/webrev.00/
>> 
>> 
>> ------------------------------------------------------------------------------
>> I might have preferred two webrevs, one of only whitespace changes and
>> one of other changes.
> 
> Yes, I'll split it up in the next version if there is a need for it.

Thanks.

>> ------------------------------------------------------------------------------
>> make/bsd/makefiles/gcc.make
>>  278     WARNING_FLAGS += -Wconversion
>> 
>> Oh, cool!  So we haven't been using that option after all!
>> 
>> Note: This is a "real change" that wasn't mentioned in the RFR.
>> 
>> I've been meaning to file a bug report against this for a while.  The
>> pre-gcc4.3 version of -Wconversion probably ought not be used in a
>> production context anyway.
>> 
>> https://gcc.gnu.org/wiki/NewWconversion
>> The old behavior for -Wconversion was intended to aid translation of
>> old C code to modern C standards by identifying places where adding
>> function prototypes may result in different behavior.  That's just not
>> an issue for C++, nor for our code in general.
>> 
>> And we're not prepared to use the new -Wconversion; see JDK-8135181.
>> 
>> So rather than changing our builds to actually use this option with
>> old compilers that Oracle doesn't support (so we can't locally test
>> this change), I suggest removing the option entirely, since it hasn't
>> actually been used anyway.
> 
> This typo was only present on bsd. Are you suggesting to remove it only on bsd, or on linux as well?

Oh, ick!  I forgot there are two of these.

*I* think it should be removed in both.  But maybe doing anything either way should be done
as a separate thing? And whatever is done here should be checked with folks like SAP who
actually build with old versions of gcc.