In Zend 5.3 they decided that closures should inherit the ##$this## from the containing scope. This brings us close to paraity with them. The remaining thing is to make
function() use ($this) {}
fatal after we purge it from WWW.
Instead of having the body of the closure be in the ##__invoke()## on the ##Closure## class, instead we make an anonymous function on the real class and put the body there. The signature for this function is:
function methodForClosure$1234($arg1, $arg2, ..., $use1, $use2, ...)
and then ##__invoke## now just takes all the params that were passed to it, puts them as the first args to the anonymous function, then takes all the use variables it had saved up and passed them in as the next params.
I tried to not have an ##__invoke## at all, but I ended up basically doing the same parameter and use var repacking in iopFCall (and would have had to do it in x86 code too). I opted for doing the rejiggering in bytecode. If I did it in raw PHP I think it would have been much slower with many ##func_get_args()## and array operations.
This diff refactors some of the VM's logic for iterators (with a focus on
mutable iteration), delivering several improvements:
1) MIterCtx was renamed to MArrayIter, and the m_key and m_val fields
were eliminated.
2) Eliminated the need for MArrayIter to dynamically allocate a
MutableArrayIter object, and removed other layers of indirection as
well.
3) Reduced the size of HPHP::VM::Iter from 64 bytes down to 32 bytes.
4) Removed the "if (siPastEnd())" check when adding a new element to an
HphpArray or a ZendArray.
5) Moved all of the iterator logic into a single .cpp file.
This diff reworks FullPos's to point to current element instead of pointing
to the next element. It also splits up the IterFree instruction into two
instructions (IterFree and MIterFree). These changes allowed various logic
to be simplified and data structures to be reduced in size. There is
definitely more opportunity for refactoring, but I know the JIT helpers for
iteration have been carefully tuned and so I'll leave further refactoring
for future diffs.
Finally, I spent a little time cleaning up the bytecode spec a bit, mostly
with respect to iteration.
This change is mostly for FB internal organizational reasons.
Building is not effected beyond the fact that the target now
lands in hphp/hhvm/hhvm rather than src/hhvm/hhvm.
ptarjan