Request for review: https://jbs.oracle.com/bugs/browse/JDK-8017473

[Joseph Provino]

It's even more confusing now!  ;-)

https://jbs.oracle.com/bugs/browse/JDK-8017473 turns out to be a 
duplicate of

https://jbs.oracle.com/bugs/browse/JDK-8011569

I closed 8017473 as a duplicate and will make a webrev for 8011569
then backport to 7u.

More comments below as to what to do.

On 7/3/2013 4:15 PM, Vladimir Kozlov wrote:
> Thank you for explaining situation, it was confusing.
>
> Since you are going to backport it into 7u40 the fix should be simple 
> and targeted. For me the suggestion to use new 
> PLATFORM_NATIVE_STACK_WALKING_SUPPORTED to fix this 8017473.
>
> As you said NMT is nothing to do with this. So using 
> PLATFORM_NATIVE_STACK_WALKING_SUPPORTED instead of 
> PLATFORM_NMT_DETAIL_SUPPORTED is also questionable.

I'm not sure what you would like.  It is okay to change 
PLATFORM_NMT_DETAIL_SUPPORTED to
PLATFORM_NATIVE_STACK_WALKING_SUPPORTED for this bug fix?  I think this 
would be the easiest
way to clean it up.  If you have another way you'd rather see it done, 
let me know.

> Why you use "PLATFORM_" prefix in names?

That's a good question.  I thought there were other names like that but 
I don't see any now.
NATIVE_STACK_WALKING_SUPPORTED seems better but perhaps because it's 
platform specific
maybe it's okay as is?  I don't feel strongly either way...

thanks.

joe

>
> Thanks,
> Vladimir
>
> On 7/3/13 12:53 PM, Joseph Provino wrote:
>> On 07/03/2013 03:27 PM, Vladimir Kozlov wrote:
>>> I don't like to have renaming done together with the fix. Is renaming
>>> required?
>>>
>>> Thanks,
>>> Vladimir
>>
>> Renaming isn't required but if I keep PLATFORM_NMT_DETAIL_SUPPORTED
>> I would need to add the new flag 
>> PLATFORM_NATIVE_STACK_WALKING_SUPPORTED.
>>
>> I could use PLATFORM_NMT_DETAIL_SUPPORTED but NMT doesn't have anything
>> to do
>> with this bug 8017473.
>>
>> What happened is that 8011064 got reported and fixed first.  The fix was
>> to disallow
>> NMT_detail in some cases so PLATFORM_NMT_DETAIL_SUPPORTED made sense.
>>
>> Bug 8017473 makes it clear that there are times when native stack
>> walking can't be done.
>> PLATFORM_NATIVE_STACK_WALKING_SUPPORTED is more general and makes 
>> sense for
>> 8011064 and 8017473.
>>
>> Do you think it would be better to use a new name and then file another
>> bug to change
>> PLATFORM_NMT_DETAIL_SUPPORTED to 
>> PLATFORM_NATIVE_STACK_WALKING_SUPPORTED?
>>
>> joe
>>
>>>
>>> On 7/3/13 12:10 PM, Joseph Provino wrote:
>>>> Bug report: https://jbs.oracle.com/bugs/browse/JDK-8017473
>>>>
>>>> This is for SE_8 but will be backported to 7u.
>>>>
>>>> Webrev: http://cr.openjdk.java.net/~jprovino/8017473/webrev.00/
>>>> <http://cr.openjdk.java.net/%7Ejprovino/8017473/webrev.00/>
>>>>
>>>> I changed PLATFORM_NMT_DETAIL_SUPPORTED to
>>>> PLATFORM_NATIVE_STACK_WALKING_SUPPORTED
>>>> to make the name more general.
>>>>
>>>> Added -DPLATFORM_NMT_DETAIL_SUPPORTED=1 to linux/makefiles/debug.make
>>>> because
>>>> with the low optimization for debug builds, -fno-omit-frame-pointer is
>>>> set and stack walking
>>>> is always permissible.
>>>>
>>>> Changed vm.make to optionally include an architecture specific 
>>>> makefile
>>>> in case some files
>>>> need to be compiled with special options such as
>>>> -fno-omit-frame-pointer.
>>>>
>>>> Thanks.
>>>>
>>>> joe
>>