Hi,
Please review this fix for dumping of long arrays, and general cleanup
of types in heapDumper.cpp.
Problem:
At several places in heapDumper.cpp overflows could happen when dumping
long arrays.
Also the hprof format uses an u4 as a record length field, but arrays
can be longer than that (counted in bytes).
Fix:
Many types that were previously signed are changed to equivalent
unsigned types and/or to a larger type to prevent overflow.
The bulk of the change though is the addition of
calculate_array_max_length, which for a given array returns the number
of elements we can dump. That length is then used to truncate arrays
that are too long.
Whenever an array is truncated a warning is printed:
Java HotSpot(TM) 64-Bit Server VM warning: cannot dump array of type
object[] with length 1,073,741,823; truncating to length 536,870,908
Much of the rest of the change is moving functions needed by
calculate_array_max_length to the DumpWriter or DumperSupport class so
that they can be accessed.
Added a test that relies on the hprof parser, which also had a couple of
overflow problems (top repo changes).
I've also run this change against a couple of other tests, but they are
problematic in JPRT because they are using large heaps and lots of disk.
Bug:
8129419: heapDumper.cpp: assert(length_in_bytes > 0) failed: nothing to copy
https://bugs.openjdk.java.net/browse/JDK-8129419
Also fixed in this change is the problems seen in these two bugs:
8133317: Integer overflow in heapDumper.cpp leads to corrupt HPROF dumps
https://bugs.openjdk.java.net/browse/JDK-8133317
8144732: VM_HeapDumper hits assert with bad dump_len
https://bugs.openjdk.java.net/browse/JDK-8144732
Webrev:
Top repo: http://cr.openjdk.java.net/~aeriksso/8129419/webrev.00/jdk9-hs-rt/
Hotspot: http://cr.openjdk.java.net/~aeriksso/8129419/webrev.00/hotspot/
Regards,
Andreas
