Code Review for JEP 259: Stack-Walking API

[Mandy Chung]

> On Nov 10, 2015, at 6:05 AM, Dmitry Samersoff <dmitry.samersoff at oracle.com> wrote:
> 
> Mandy,
> 
> Native part looks good for me.
> 
> javaClasses.cpp:
> 
> 1. It might be good to create a helper inline function for
> 
>  int bci_version = stackFrame->int_field(bci_offset);
>  int version     = BackTrace::version_at(bci_version);
> 

Coleen gave me some suggestion to use injected fields.  This will be changed in the next revision.

> 2. java_lang_StackFrameInfo::fill_methodInfo
> 
>  CHECK macro left methodInfo partially initialized, not sure it's OK.
> 

Any exception here will cause StackWalker::walk to fail.  I expect the exception thrown here  would be OOME and other internal errors.  So it should be okay.

> javaClasses.inline.hpp:
> 
> 78 You can use the same pattern as in assert:
> 
>    if ((jushort)version != version) version = USHRT_MAX;
> 
> 117 Is it possible to add comment about +1000000 magic?
> 

This is existing code refactored from javaClasses.hpp.  I don’t know why it added  +1000000.  For hidden frames, keeping line number to -1 is good to me since it means unavailable.

Coleen - do you know why this is done this way?

> jvm.cpp:
> 
> 627 missed space around =

Fixed.
Mandy