This may seem a bit of a risky change, in that it may introduce crazy
bugs with respect to volatile variables in the VM loop. But, I think it
should be fine: code_state points to some external memory, so the
compiler should always read/write to that memory when accessing the
ip/sp variables (ie not put them in registers).
Anyway, it passes all tests and improves on all efficiency fronts: about
2-4% faster (64-bit unix), 16 bytes less stack space per call (64-bit
unix) and slightly less executable size (unix and stmhal).
The reason it's more efficient is save_ip and save_sp were volatile
variables, so were anyway stored on the stack (in memory, not regs).
Thus converting them to code_state->{ip, sp} doesn't cost an extra
memory dereference (except maybe to get code_state, but that can be put
in a register and then made more efficient for other uses of it).
Conflicts:
py/vm.c
Fixed stack underflow check. Use UINT_FMT/INT_FMT where necessary.
Specify maximum VM-stack byte size by multiple of machine word size, so
that on 64 bit machines it has same functionality as 32 bit.
This improves stack usage in callers to mp_execute_bytecode2, and is step
forward towards unifying execution interface for function and generators
(which is important because generators don't even support full forms
of arguments passing (keywords, etc.)).
Needed to pop the iterator object when breaking out of a for loop. Need
also to be careful to unwind exception handler before popping iterator.
Addresses issue #635.
This helps the compiler do its optimisation, makes it clear which
variables are local per opcode and which global, and makes it consistent
when extra variables are needed in an opcode (in addition to old obj1,
obj2 pair, for example).
Could also make unum local, but that's for another time.
This completes non-automatic interning of strings in the parser, so that
doc strings don't take up RAM. It complicates the parser and compiler,
and bloats stmhal by about 300 bytes. It's complicated because now
there are 2 kinds of parse-nodes that can be strings: interned leaves
and non-interned structs.
io.FileIO is binary I/O, ans actually optional. Default file type is
io.TextIOWrapper, which provides str results. CPython3 explicitly describes
io.TextIOWrapper as buffered I/O, but we don't have buffering support yet
anyway.
Now schedule is: for native types, we call ->make_new() C-level method, which
should perform actions of __new__ and __init__ (note that this is not
compliant, but is efficient), but for user types, __new__ and __init__ are
called as expected.
Also, make sure we convert scalar attribute value to a bound-pair tight in
mp_obj_class_lookup() method, which avoids converting it again and again in
its callers.
Damien George
Paul Sokolovsky
Kim Bauters
Sven Wegener