RFR(S) 8161598,,Kitchensink fails: assert(nm->insts_contains(original_pc)) failed: original PC must be in nmethod/CompiledMethod

[Frederic Parain]

Dean,

In file macroAssembler_x86.cpp, could it be possible to
get rid of the clear_pc argument? It seems completely
useless now.

Fred


On 08/09/2016 01:39 PM, dean.long at oracle.com wrote:
> Ping.
>
> dl
>
>
> On 8/4/16 3:28 PM, dean.long at oracle.com wrote:
>> https://bugs.openjdk.java.net/browse/JDK-8161598
>>
>> http://cr.openjdk.java.net/~dlong/8161598/webrev/
>>
>> Sorry, this issue is Confidential.  The problem is similar to 8029441,
>> where we suspend a thread and use pd_get_top_frame_for_profiling() to
>> get the top frame for stack walking.  The problem is "last Java frame"
>> anchor frames on x86. In lots of places we do not store last_Java_pc.
>> This is OK in the synchronous stack walk case done by the current
>> thread.  But in the asynchronous case, there are small windows where
>> it's not always safe to get PC from sp[-1].
>>
>> The solution is not to treat x86 anchor frames as "always walkable".
>> Instead, we follow the example of sparc and make them walking by
>> filling in last_Java_pc when it's safe.
>>
>> I went for the minimal fix, resetting clear_pc to true in
>> reset_last_Java_frame() but not changing the API and all the callers.
>> I can fix this if reviewers feel strongly about it.
>>
>> dl
>>
>