spice/lib/compile/bcc.ml

137 lines
4.2 KiB
OCaml

module Ast = Spice_syntax.Ast
module Code = Spice_runtime.Code
module Value = Spice_runtime.Value
module Env = Map.Make (String)
type binding = {
self : Code.regidx;
slot : Value.slotidx;
}
let compile modl =
let ep = Code.make_basic_block [] in
let sp = ref 0 in
let bb = ref ep in
let emit is = Code.add_ins !bb is in
let emit_mov lhs rhs = if rhs <> Code.Reg lhs then emit (MOV (lhs, rhs)) in
let rec compile_exp env = function
| Ast.Literal Nil -> Code.Cst_nil
| Ast.Literal True -> Code.Cst_true
| Ast.Literal False -> Code.Cst_false
| Ast.Literal (Int i) -> Code.Cst_int i
| Ast.Path (Var name) -> (
match Env.find name env with
| exception Not_found -> Fmt.failwith "unbound: %S" name
| { self; slot } ->
let ret = !sp in
sp := ret + 1;
emit_mov ret (Code.cst_of_int slot);
emit (GET (self, ret));
Reg ret)
| Ast.Binop (op, lhs, rhs) ->
let ret = !sp in
let lhs = compile_exp env lhs in
emit_mov ret lhs;
sp := ret + 1;
let rhs = compile_exp env rhs in
(match op with
| Ast.Add -> emit (ADD (ret, rhs))
| Ast.Sub -> emit (SUB (ret, rhs))
| Ast.Mul -> emit (MUL (ret, rhs))
| Ast.Div | Ast.Mod -> failwith "Bcc.compile_exp: TODO: div/mod"
| Ast.Eql -> emit (EQL (ret, rhs))
| Ast.Not_eql ->
emit (EQL (ret, rhs));
emit (NOT ret)
| Ast.Lst -> emit (LST (ret, rhs))
| Ast.Lst_eql ->
emit (LST (ret, rhs));
emit (NOT ret)
| Ast.Grt -> emit (GRT (ret, rhs))
| Ast.Grt_eql ->
emit (LST (ret, rhs));
emit (NOT ret));
Reg ret
| Ast.If (cnd, e1, e2) ->
let l1 = Code.make_basic_block [] in
let l2 = Code.make_basic_block [] in
let jp = Code.make_basic_block [] in
let tmp = !sp in
emit (CBR (compile_exp env cnd, l1, l2));
sp := tmp;
bb := l1;
emit_mov tmp (compile_exp env e1);
emit (JMP jp);
sp := tmp;
bb := l2;
emit_mov tmp (compile_exp env e2);
emit (JMP jp);
sp := tmp + 1;
bb := jp;
Reg tmp
| Ast.Obj body -> compile_obj env body
| Ast.Scope body -> compile_scope env body
| _ -> failwith "Bcc.compile_exp: TODO"
and compile_block env items =
let self = !sp in
(* construct new env and vtable *)
let elems = Hashtbl.create (List.length items * 2) in
let env, n_slots =
List.fold_left
(fun (env, n) -> function
| Ast.Item_fun (_, _, _) | Ast.Item_exp _ -> env, n
| Ast.Item_obj (name, _) | Ast.Item_val (name, _) ->
let slot = n in
let env = Env.add name { self; slot } env in
Hashtbl.add elems name (Value.Field slot);
env, n + 1)
(env, 0)
items
in
let vtable = Value.{ elems; n_slots } in
(* emit constructor, compile val fields, and get result of final expression *)
emit (CON (self, vtable));
let emit_set name rhs =
let slot = (Env.find name env).slot in
emit_mov (self + 2) rhs;
emit_mov (self + 1) (Code.cst_of_int slot);
emit (SET (self, self + 1))
in
let final_exp =
List.fold_left
(fun _ -> function
| Ast.Item_fun (_, _, _) -> failwith "Bcc: unsupported: methods"
| Ast.Item_exp e ->
sp := self + 1;
Some (compile_exp env e)
| Ast.Item_obj (name, body) ->
sp := self + 2;
emit_set name (compile_obj env body);
None
| Ast.Item_val (name, rhs) ->
sp := self + 2;
emit_set name (compile_exp env rhs);
None)
None
items
in
self, final_exp
and compile_obj env items =
let self, _ = compile_block env items in
sp := self + 1;
Code.Reg self
and compile_scope env items =
match compile_block env items with
| _, None -> failwith "block must end with an expression"
| _, Some ret -> ret
in
let env = Env.empty in
emit_mov 0 (compile_obj env modl.Ast.items);
emit RET;
Code.make_program ep