RFR: 8219241: Provide basic virtualization related info in the hs_error file on linux/windows x86_64

[David Holmes]

Hi Matthias,

On 5/04/2019 6:26 pm, Baesken, Matthias wrote:
>>
>> So compiler ifdefs in the cpu files is the way to handle this.
>>
> 
> Hello, I moved the  coding from
> 
> src/hotspot/os_cpu/linux_x86/vm_version_linux_x86.cpp
> src/hotspot/os_cpu/windows_x86/vm_version_windows_x86.cpp
> 
> 
> Into src/hotspot/cpu/x86/vm_version_x86.cpp   and guarded it with the compiler macros :
> 
> http://cr.openjdk.java.net/~mbaesken/webrevs/8219241.5/

I'm not clear why we are still using os-guards as well?

+ #elif defined(__GNUC__) && defined(__linux__)

+ #if defined(_LP64) && (defined(__linux__) || defined(_WIN64))

won't this code still execute okay on Solaris/BSD/MacOS ?

Thanks,
David

> Thanks, Matthias
> 
> 
> 
>> -----Original Message-----
>> From: David Holmes <david.holmes at oracle.com>
>> Sent: Freitag, 5. April 2019 00:50
>> To: Baesken, Matthias <matthias.baesken at sap.com>; 'hotspot-
>> dev at openjdk.java.net' <hotspot-dev at openjdk.java.net>
>> Cc: Doerr, Martin <martin.doerr at sap.com>
>> Subject: Re: RFR: 8219241: Provide basic virtualization related info in the
>> hs_error file on linux/windows x86_64
>>
>> On 4/04/2019 10:35 pm, Baesken, Matthias wrote:
>>>>
>>>> On 4/04/2019 8:54 pm, Baesken, Matthias wrote:
>>>>>>
>>>>>> My remaining query is why we need the OS specific checks and code in
>>>>>> os-cpu files? Isn't this just cpu specific? Even if a particular OS
>>>>>> doesn't support virtualization, won't the cpuid query simply report "no
>>>>>> virtualization"?
>>>>>>
>>>>>
>>>>> Hi David,  if you are referring to  these  os-cpu files  :
>>>>>
>>>>> src/hotspot/os_cpu/linux_x86/vm_version_linux_x86.cpp
>>>>> src/hotspot/os_cpu/windows_x86/vm_version_windows_x86.cpp
>>>>>
>>>>> we have different coding available  because  I am not aware  of a cross
>> OS
>>>> API/coding to get   the cpu id info.
>>>>> That’s why different coding for LINUX/Windows.
>>>>
>>>> ?? But there's nothing in those added functions that is Linux specific
>>>> or Windows specific! The only difference is the mechanism for doing
>>>> "inline assembly" and that's compiler specific. So this should just use
>>>> compiler based ifdefs in vm_version_x86.cpp.
>>>>
>>>
>>> Hi David, I see your point.  But I thought we want to reduce the  ifdefs and
>> favor  putting code into the os or os/cpu  specific  files .
>>> But it is true , from a technical point  we could do using the compiler macros
>> .
>>
>> I favour putting os-specific code in os-specific files over OS ifdefs in
>> shared files. But here we are talking about compiler-specific code that
>> is also CPU specific (not os specific). So compiler ifdefs in the cpu
>> files is the way to handle this.
>>
>> Thanks,
>> David
>>
>>> Best regards, Matthias
>>>
>>>