Request for review: JDK-8011569 ARM: avoid native stack walking

[Joseph Provino]

The latest webrev is here: 
http://cr.openjdk.java.net/~jprovino/8011569/webrev.00/ 
<http://cr.openjdk.java.net/%7Ejprovino/8011569/webrev.00/>

David Holmes already approved these changes when the review request was 
for 8017473.

thanks.

joe


On 7/3/2013 4:52 PM, Joseph Provino wrote:
> 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
>>>
>