We'd like to start using ##mixed## instead of ##var## for attribute types to be consistent with Hack. As a followup to this (once released), we would codemod all ##var## to ##mixed##.
The codebase had several namespace-level static data definitions and function definitions. Using namespace-level "static" in a .h file is near-always a bad idea, as follows:
- for simple types, static is implied. Example: "const int x = 42;" is the same as "static const int x = 42;"
- for aggregate types, static linkage implies that a copy of the aggregate will appear in every compilation unit that includes the header.
- for functions, static means the function will have a separate body generated in each compilation unit including the header.
- in several places functions were defined 'static inline', which is just as bad. 'inline' is just a hint which means the function may end up having a body (and actually more due to 'static').
True, gnu's linker has means to remove duplicate definition, but that's not always guaranteed or possible (think e.g. static functions that define static data inside, ouch). So static is useless at best and pernicious at worst. We should never, ever use static at namespace level in headers. I will create a bootcamp task for a lint rule.
I expected the performance to be neutral after the change, but in fact there's a significant drop in instruction count and therefore a measurable reduction in CPU time: https://our.intern.facebook.com/intern/perflab/details.php?eq_id=431903
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 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.
Kyle Delong