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.
Access to TypedValue.m_aux must now be via TypedValueAux. For now,
TypedValueAux is an empty subclass with accessors to m_aux, which is
now private. Once RefData.m_tv is moved out from under RefData._count,
we can move TypedValue.m_aux to TypedValueAux.
Removed unnecessary initialization of m_aux.u_hash from c_Vector.
This diff removes initializing stores to TypedValue._count, renames
_count to m_aux, and makes m_aux a union with members typed
and named according to their specialized uses. The few remaining
uses of that field for random tweaks are more obvious and easy to
grep for.
TypedValue no longer extends Value, (allowing m_data to move to a
different offset in the future), and Variant now extends TypedValue,
so we only have to maintain one definition.
HphpArray now explicitly uses TypedValue.m_pad instead of overlapping
TypedValue with an anonymous struct, again so we don't have to maintain
another structure to match TypedValue's layout.
The JIT's were using offsetof(TypedValue, _count) all over the place
for access to String/Array/Object/RefData::_count. Instead, use
FAST_REFCOUNT_OFFSET.
I found some byte-wide padding in Unit and UnitEmitter that we can
use to store the mergeOnly flag, instead of m_returnValue's unused
_count field. This is one step towards eliminating TV._count.
This turns the output into three columns: tx64 asm, hhir asm,
then pretty-printed hhir with asm inline. This should help us figure
out what the ir is doing wrong when it makes bigger code. I also
compacted the output of Trace::print a bit and changed it to print
unlikely blocks at the very end.
I found 4 separate problems, each of which broke this:
- A hoistable class didnt generate bytecode, so the line number
information was associated with whatever line the /next/
bytecode corresponded to. Often there was no next bytecode,
so we got the line number of the end of the file.
- If there /was/ a bytecode for the defClass, the line number
recorded for it was that of the pseudoMain, not the class
itself; so again, it would be reported as the end of the file.
- The parser records two sets of line numbers for a class; its
start, and end. The end line gets associated with the bytecode.
- There were optimized paths where we didnt setup an ActRec
at all, resulting in either reporting the file/line of the
require (or often a require much higher up the stack), or
not reporting a file/line at all.
So now, we generate a nop if we would have skipped the defCls.
We override the normal line info, and set both the start and end
lines to the start. And we wrap all errors from defClass in a
temporary frame to ensure the line info is seen.
This changed the output for several of our tests. Spot checking
a couple showed they now report the same line number as zend.
Try to scoop up some more instructions in the IR. In a
sequence like:
BoringInstrA
BoringInstrB
PuntInstr
BoringInstrC
we used to punt the entire tracelet to interp. Now we do:
hhir:
BoringInstrA
BoringInstrB
interp:
PuntInstr
BoringInstrC
Rescuing BoringInstrC from PuntInstr is future work.
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