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

[Magnus Ihse Bursie]

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.

/Magnus


>
> /Erik