This diff cleans up some of the mess in SharedMap. The existing way of accessing values in ShareMap is SharedMap -> SharedVariant -> ImmutableMap -> SharedVariant. This diff changes it so that the path is reduced to SharedMap -> ImmutableMap (with inlined SharedVariants).
(Likewise for VectorData)
The hashing scheme in ImmutableMap is left unchanged (chaining with ->next pointers, though we could change it to something similar to HphpArray).
Elide refcounting for non-refcounted TVs in SharedVariant.
Additionally for apc_store, if TV is a static string, use
the static version insted of the given one.
I was learning from @jdelong and he said that you should use
double quotes for local includes and angle brackets for library
includes. I asked why our code was the way it was, and he said he wanted
to clean it up. I beat him to it :)
Conflicts:
hphp/runtime/base/server/admin_request_handler.cpp
hphp/runtime/vm/named_entity.h
This gets rid of the (litstr) StringData and StackStringData
constructors, but keeps String(litstr). Also rename all
the instances of AttachLiteral to CopyString, since they now
mean the same thing.
Streamline the array access methods by always returning an array
pointer instead of a new pointer or null. Callsites compare
(new != old) to detect escalation, rather than (new != null).
Fixing various bugs all over the VM that make assumptions about RefData
and TypedValue layout. Here are the assumptions fixed by this diff:
offsetof(RefData, m_tv) == 0. Both JIT's assumed this in many subtle
ways, by punning RefData* as TypedValue* without adding an offset.
This assumption also causes RefData._count to overlap TypedValue.m_aux,
which constraints TypedValue layout.
offsetof(TypedValue, m_data) == 0. gen_ext_hhvm.php assumes you
can cast TypedValue* to Value*; the JITs often weren't using
offsetof(TypedValue, m_data) in their addressing calculations. HHIR
assumed return-by-value TV's have m_data/m_type in rax/rdx, which
can change when TV layout changes.
offsetof(TypedValue, m_type) > 8 is an assumption baked into the
pass-by-value register assignment logic in HHIR's codegen.cpp; if
the type is in the low word, register assignment is swapped.
sizeof(TypedValue::m_type) == 4. We used dword-sized operations
in both JIT's when accessing m_type. Now, we use helper functions
that are sensitive to sizeof(DataType)
Configuration:
DEBUG=: (opt) same layouts as trunk for RefData & TypedValue
DEBUG=1: (dbg) new RefData layout (m_tv doesn't overlap RefData::_count)
PACKED_TV=1, DEBUG=*: new RefData and TypedValue layout.
SharedMap was the last dependency on ZendArray. For its localCache,
use a TypedValue[] array indexed by SharedVariant.getIndex(), and
for escalate(mutableIteration), escalate to an HphpArray instead of
a ZendArray.
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.
Tim Starling