RFR: JDK-8148929: Suboptimal code generated when setting sysroot include with Solaris Studio

[David Holmes]

On 4/02/2016 9:27 PM, Magnus Ihse Bursie wrote:
> On 2016-02-03 14:33, Erik Joelsson wrote:
>>
>>
>> On 2016-02-03 13:59, David Holmes wrote:
>>> Hi Erik,
>>>
>>> On 3/02/2016 10:48 PM, Erik Joelsson wrote:
>>>> Hello,
>>>>
>>>> Please review this small fix for building on Solaris using a
>>>> devkit/sysroot. The Solaris Studio compiler does special inlining and
>>>> intrinsics with system calls, like memcpy. The problem is that it only
>>>> seems to do this if it finds the definition of the system call in a
>>>> header file in the /usr/include directory. See bug description and
>>>> comments for details.
>>>>
>>>> I have found a way to work around this. Internally, the compiler adds
>>>> the option -I-xbuiltin to mark the start of the system header includes
>>>> when calling a sub process. By adding this to our SYSROOT_CFLAGS, the
>>>> special inlining is re-enabled.
>>>
>>> We have no way of knowing whether that will mess with the compilers
>>> use of other header files. We seem to be on very thin ice here. We
>>> know it fixes this one problem, but we don't know what else it may do!
>>>
>> That is true. But then, we don't really know what else this compiler
>> is doing anyway, as is evident by your latest discovery. The way we
>> live with this is testing. We use the setup we have until it proves
>> not to work, we fix and we test. I'm just trying to do the best I can
>> with what we have. I would much prefer to ditch SS for gcc/clang
>> (where we seem to have way less problems) if it was my choice. I'm not
>> ready to give up the convenience of devkits/portable sysroots just
>> because one of the compilers we (have to) use needs a bit of special
>> handling to behave properly.
>
> I agree that this is a situation that's not really comfortable. :( But,
> as with many other things with the solaris studio compiler, in the end
> it's a result of the limited functionality of that compiler (in this
> case, the lack of a properly functioning --sysroot alternative).
>
> So in light of that, and Erik's comment about testing as the only way to
> be sure, I'd like to see Eriks fix get in.

Do we have the means to do a binary comparison of the object files 
before/after the change to ascertain what kind of affect this is having?

Thanks,
David

> /Magnus
>
>
>>
>> /Erik
>