Projects/frostbyte-39
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Bytecode needs/design goals/whatever
- Initial overview: do it a function at a time. Function calls still
do callAsFunction:
* But can setup the arguments on the stack frame, along with the length. List integration with that may be tricky, especially for native calls.
- Goal #1: cheap temporaries --- make the wiring inexpensive
* M.O.: my tendency is towards simpler bytecode (think Copy4, Copy8),
for simpler optimization; critical for that, nice otherwise
* All accesses to temporaries, locals should be simple offsets
* Can compute stack size need easily: just have a
ByteCodeTemp class that links in to a counter in
compilation context. So there is no need to put in conditionals
on push/pop. Also, this gives the temporaries an explicit name,
which can be in a shared namespace with locals. Somewhat (see below)
* Keep track of stack pointer?
* Pro: less ++ / --
* Con: garbage can linger
* Basic compilation interface for evaluate:
void evaluateTo(CompileState* comp, ByteCodeTemp& dest);
* A simple peephole optimization on reads for this:
t1 = local;
t2 = t1 * t3;
will probably be a good idea. Not sure if full copy prop is worth anything
* Limit reallocations -- entering a context should do only a single stack frame allocation
- Literals should go into some sort of a symbol table
- Obviously, would like globals to used all of the above
* Problem: symbol tables, stack frames might grow. May require segmenting them an multiple subst