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.
Of the four horsemen of the SmartAllocator, ArrayData was the only virtual
call. This meant an extra layer of indirection when coming from the TC
to allow the c++ compiler to emit its virtual call, and slightly larger
callsites when using non-generic paths.
While we're moving in this direction, consolidate ArrayData introspection
on its type enum. isSharedMap() was previously implemented with a vtable
slot, and we had no way of asking if an ArrayData was a NameValueTable.
The only places where ReturnStatement is constructed are:
- onReturn(check_yield=true) -> not allowed in generator
- onReturn(check_yield=false) -> coming from transform_yield_break, right after creating hphp_continuation_done()
- MethodStatement, end of function call -> hphp_continuation_done() is created at end of generator in prepare_generator()
Emitter is emitting ContExit in ReturnStatements used in generators. As
can be seen from the analysis above, it's always preceded by emitting
ContDone from hphp_continuation_done(). Let's emit ContDone inside the
ReturnStatement directly and kill usage of hphp_continuation_done().
transform_yield_break() becomes a simple onReturn(check_yield=false), so
let's inline it into onYield and create ReturnStatement directly. After
this change, check_yield flag is always true and can be killed.
ContExit was also used after emitting a generator method in case the end
of method is still reachable. ContDone is added so that the generator is
properly closed. I believe this is never actually used, as MethodStatement
creates ReturnStatement at the end of method anyway.
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.
Alias manager does not know whether generator parameters are passed by
reference. This didn't matter, because every generator had at least one
function call (hphp_continuation_done()) that pretty much disabled unused
variable elimination.
This diff fixes that, lets us get rid of artificial function calls in
generators and will allow later improvements in alias manager.
Alias manager does not know that generator parameters are populated and
assumes they are uninit. The current code works because control flow
algorithm gives up while trying to deal with the continuation switch
statement full of gotos.
This diff fixes it by setting isGeneratorParameter flag in symbols
representing parameters of enclosing generator wrapper and use variables
of enclosing closure.
PHP added this in 5.4 so that you can say your closure shouldn't capture ##$this##. https://wiki.php.net/rfc/closures
Should we add it? Many of their unit tests use it.
Instead of putting a boolean somewhere I used the same attr framework and set the static bit there. Thoughts? It only needs one change in the ##FPushFunc##.
In Zend 5.3 they decided that closures should inherit the ##$this## from the containing scope. This brings us close to paraity with them. The remaining thing is to make
function() use ($this) {}
fatal after we purge it from WWW.
{get,set}NthKid() should be only used to walk thru all the kids and not to get/set a known specific kid. Replace its use by direct helper method.
All remaining callers of {get,set}NthKid() were audited and there are no instances left accessing specific kid.
This diff introduces assert_throw, assert_log, and always_assert_ versions of
the two. They behave similarly to assert, but assert_throw throws a
FailedAssertion exception instead of calling abort. This lets us catch the
exception and add additional debug info to the stacktrace file. In the case of
the IR, this is the current Trace. assert_log takes the condition to check and
a lambda that is expected to return a std::string. If the condition fails, the
lambda will be evaluated and the text returned will be included in the
stacktrace file.
I've left assert_throw off by default so people have to opt into it
locally or in Perflab (see the comment in assert_throw.h)
It's easy to introduce bug by adding a new expression and not defining
its ListAssignment RHS kind. Add all expression types explicitly and
remove default case so that it becomes compile time error if the list is
not updated.
In HHBC mode, traits are flattened into their classes.
When that happens, closures need to know about all the
classes that contain them so that when we find a ##$this##
inside the closure, it can tell EVERY containing scope to
please propogate ##$this## down to me.
This diff removes LVariableTable, RVariableTable, and getHphpBinaryType().
It also consolidates some of the include logic that was spread across
multiple files.
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.
closures will need to know at emission time whether there is a
static $foo;
statement inside them, because if there is, the closure has to stick around to hold the static locals.
This is the last step to being able to get rid of the c++ code
gen in hphp. "make -Chphp/system" is now a no-op.
I'll rip out the actual c++ generating code as a separate diff.
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 diff updates the parser and runtime to support using collection
literals in initializer expressions for instance properties, static
properties, parameters, and static locals.
The runtime as-is was able to correctly handle collection literals in
initializers for static properties, parameters, and static locals. However,
for instance properties I needed to way to make it so that each instance
got a fresh copy of the collection literal.
To achieve this, I added an attribute to indicate that a property requires
'deep' intiialization. When this attribute is set, the Class machinery
will not call setEvalScalar() on the initial value (the value produced by
86pinit), and it will make a deep copy of the initial value when a new
instance of the Class is allocated.
Support == and != operators for collections. Also fix some bugs the <, <=,
>, and >= operators when comparing two objects or when comparing an array
with an object.
The variable declared in an if condition cant be redeclared in the
(outermost scope of the) else.
g++4.7.1 treats FOO as a literal suffix operator in "x"FOO, even if FOO
is a macro whose expansion wouldnt qualify (not sure if this is a bug
in g++4.7.1)
jan