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

Magnus Ihse Bursie magnus.ihse.bursie at oracle.com
Thu Feb 4 20:33:03 UTC 2016

Blir det skillnader mot vårt gamla bygge med devkit men utan din nya fix, eller mellan devkit med din fix och en icke-devkit där man inte använder sysroot? Dvs kan din fix göra så att devkit blir identiskt med utan devkit?


> 4 feb. 2016 kl. 14:51 skrev Erik Joelsson <erik.joelsson at oracle.com>:
> Differences are extensive in most C++ object files. The problem with viewing dissassembly diffs is that any difference tend to change all addresses later in the file.
> /Erik
>> On 2016-02-04 13:43, Erik Joelsson wrote:
>> I will investigate and report back.
>> /Erik
>>> On 2016-02-04 13:29, David Holmes wrote:
>>>> 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

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