Fixes HHIR bugs that were causing perflab crashes: guards on
class types and tvBox.
We were ignoring stack guards on class, which was causing the IR to
lose track of types for classes on the stack and causing assertion
failures. Fixed by making class stack type guards into stack type
asserts.
tvBox was not returning the right value, causing VGetS to crash in the
IR.
Changed 1 test and added another to cover VGetS in verify_quick_hhir.
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 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.
alia