Merge ContDone+ContExit into ContRetC with added support of passing results. This variable passing mechanism is not exposed to the PHP as the ReturnStatements in generators do not contain result expression. However, this is exposed by restored hphp_continuation_done() built-in to allow experimentation.
The idea is that once we introduce ContYield opcode (merge of all opcodes used by YieldExpression), we could change ContRetC and ContYield to leave result and done-status on the stack and leave it up to the caller (ContNext/ContSend/ContRaise) to fill in Continuation fields. This will make these opcodes more generic and useful for other things, while allowing us to move some properties to the VM and kill opcodes like ContCurrent.
Continuation::send() uses m_received field to transfer the value inside
the continuation. This field remains set until the continuation is
iterated the next time.
Unset this field early by ContReceive so that the memory can be
reclaimed.
Unhack the parser and introduce YieldExpression that emits the
equivalent set of opcodes that were emitted by bunch of
expressions/statements generated by parser before.
YieldExpression expects evaluation stack to contain just the value
being yielded, so {,List}AssignmentExpression need to evaluate RHS
first. The previous code had the same behavior.
This will let us consolidate continuation-related opcodes and make
them less tied with continuation objects.
Inlined the fast-path of FPushObjMethodD in the IR from
MethodCache::lookup. This should reduce the number of times we call
the MethodCache::lookup helper by inlining the common case where the
object's class hits in the target cache.
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.
Broke LdClsPropAddr into 2 instructions by introducing a
ldClsPropAddrCached. LdClsPropAddrCached loads the static property via
the target cache so requires the class and property name to be
compile-time constants. LdClsPropAddr does not use the target cache
and works even if the property and class names are not constant.
Similarly broke LdCls into 2 by introducing LdClsCached. LdClsCached
uses the target cache to handle the case where the class name is a
compile time constant. Added code to detect cases where the class name
can be folded to a Class* constant.
Moved the code that decides between LdCls (LdClsPropAddr) and
LdClsCached (LdClsPropAddrCached) to the simplifier, allowing us to
optimize these instructions as optimization passes discover more
constants.
Changed HhbcTranslator code generation for AGet* and getClsPropAddr to
handle more cases using the above new instructions. Also improved
HhbcTranslator's translations for self and parent bytecodes.
Added a label to LdClsPropAddr to allow control flow when property is
not accessible. This enables implementation of IssetS (which was
incorrect before this diff) and EmptyS.
Implemented BindS, VGetS, EmptyS, and LateBoundCls.
Opportunitistically introduces calls to SSATmp::isA(...) to replace
explicit comparisons against Type::Tag values.
Moved AddElem punt from code generator to hhbctranslator so that we
can interpone.
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.
Implements AKExists in HHIR. I've added a new IR opcode for it which
basically generates a call to helper method (which is very similar to
the tx64 helper). The major difference is putting the decrefs in the
IR rather than the helper.
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.
jan