We must call notifyAll on visitLock after setting threadVisitor to
null in case another thread is waiting to do a visit of its own.
Otherwise, the latter thread will wait forever, eventually deadlocking
the whole VM at the next GC since it's in an active state.
1. HashMap.containsValue only checked one hash bucket, which was
pretty much useless :)
2. HashMap.MyIterator.remove was broken in that it failed to
decrement the size field and it did not update the previousCell field
properly, which sometimes led to more than one cell being removed.
If the VM runs out of heap space and the "avian.heap.dump" system
property was specified at startup, the VM will write a heap dump to
the filename indicated by that property. This dump may be analyzed
using e.g. DumpStats.java.
This makes heap dumps more useful since these classes are now refered
to by name instead of number.
This commit also adds a couple of utilities for parsing heap dumps:
PrintDump and DumpStats.
The primary change is to ensure we output a Mach-O file of appropriate
endianness when cross-compiling for an opposite-endian architecture.
Earlier versions of XCode's linker accepted files of either
endianness, reguardless of architecture, but later versions don't,
hence the change.
Previously, loading an arbitrary 32-bit constant required up to four
instructions (128 bytes), since we did so one byte at a time via
immediate-mode operations.
The preferred way to load constants on ARM is via PC-relative
addressing, but this is challenging because immediate memory offsets
are limited to 4096 bytes in either direction. We frequently need to
compile methods which are larger than 4096, or even 8192, bytes, so we
must intersperse code and data if we want to use PC-relative loads
everywhere.
This commit enables pervasive PC-relative loads by handling the
following cases:
1. Method is shorter than 4096 bytes: append data table to end
2. Method is longer than 4096 bytes, but no basic block is longer
than 4096 bytes: insert data tables as necessary after blocks, taking
care to minimize the total number of tables
3. Method is longer than 4096 bytes, and some blocks are longer than
4096 bytes: split large basic blocks and insert data tables as above
Previously, we waited until the next GC to do this, but that can be
too long for workloads which create a lot of short-lived threads but
don't do much allocation.
The first bug affected POSIX systems: if the app never called
Process.waitFor, we'd never call waitpid on the child and thus leak a
zombie process. This patch ensures that we always call waitpid by
spawning a thread to handle it.
The second bug affected Windows systems: we weren't closing the
child's ends of the stdin, stdout, and stderr pipes after process
creation, which lead to us blocking forever while reading from the
child's stdout or stderr.
This requires adding LinkRegister to the list of reserved registers,
since it must be preserved in the thunk code generated by
compileDirectInvoke. An alternative would be to explicitly preserve
it in that special case, but that would complicate the code quite a
bit.
Due to a silly cut-and-paste error, we were incorrectly passing the
stdout and stderr file descriptors back from native code to Java,
which prevented reading the output of the child process.
We were incorrectly returning an empty array when the input was empty,
whereas we ought to return an array containing a single empty string.
When the pattern to match was empty, we went into a loop to create an
infinite list of empty strings, only to crash once we've run out of
memory. This commit addresses both problems.
