On 2012-11-21 20:17, David Holmes wrote:
Hi Mikael,
On 22/11/2012 11:42 AM, Mikael Vidstedt wrote:
Please review the below change.
The change for 7045397 introduced a couple of duplicate entries
in the
vmStructs::localHotSpotVMTypes array. This shows up when using the
jmap
tool in a rather ugly way:
<snip>
Other than an indentation problem (which I don't think you
introduced) this fixup seems fine.
For some reason that's the standard for declaring types in that long
list - aligning on the first letter of the type name. I followed
suit.
In addition to removing the two duplicated entries I also added a
simple, naive runtime test to walk through and make sure no
type is
repeated. The VMStructs::init only called in debug_only so
there's no
startup overhead in product, but it may be better to turn the test
into
a unit test and only running it as part of ExecuteInternalVMTests.
Feedback appreciated!
I have a few comments on this part:
- Array indices should be int's not size_t (ie signed not unsigned)
Will fix.
- I can't clearly see how the localHotSpotVMTypes array is declared
or filled but I assume there is guaranteed to be a sentinel
entry at
the end so that we don't index past the end?
Yeah. I'm not sure you want to know. It took me a few minutes to
figure it out. It turns out that the GENERATE_VM_TYPE_LAST_ENTRY
macro which generates the end marker is passed to VM_TYPES,
VM_TYPES_CPU and VM_TYPES_OS_CPU. But only the last one is
allowed to
actually allowed to call the macro and actually generate the marker,
meaning only the "implementation" of VM_TYPES_OS_CPU actually has
the
call to last_entry(). Not sure why the end marker isn't just
explicitly added at the end instead, but I think I'll queue that up
for later.
All in all, as far as I can tell there is one and only one end
marker
and it is generated as part of the expansion of VM_TYPES_OS_CPU.
- assert(0, ...) should be assert(false, ...) (as per style guide
[1] ;-) )
Will fix.
That all said I'm not sure this test belongs there, but I don't
feel
strongly either way.
Me neither :)
Cheers,
Mikael
Cheers,
David
[1] https://wikis.oracle.com/display/HotSpotInternals/StyleGuide
http://cr.openjdk.java.net/~mikael/8003879/webrev.00/
Cheers,
Mikael
