SX bytecode: format definition, compiler, OCaml VM (Phase 1)
Three new files forming the bytecode compilation pipeline:
spec/bytecode.sx — opcode definitions (~65 ops):
- Stack/constant ops (CONST, NIL, TRUE, POP, DUP)
- Lexical variable access (LOCAL_GET/SET, UPVALUE_GET/SET, GLOBAL_GET/SET)
- Jump-based control flow (JUMP, JUMP_IF_FALSE/TRUE)
- Function ops (CALL, TAIL_CALL, RETURN, CLOSURE, CALL_PRIM)
- HO form ops (ITER_INIT/NEXT, MAP_OPEN/APPEND/CLOSE)
- Scope/continuation ops (SCOPE_PUSH/POP, RESET, SHIFT)
- Aser specialization (ASER_TAG, ASER_FRAG)
spec/compiler.sx — SX-to-bytecode compiler (SX code, portable):
- Scope analysis: resolve variables to local/upvalue/global at compile time
- Tail position detection for TCO
- Code generation for: if, when, and, or, let, begin, lambda,
define, set!, quote, function calls, primitive calls
- Constant pool with deduplication
- Jump patching for forward references
hosts/ocaml/lib/sx_vm.ml — bytecode interpreter (OCaml):
- Stack-based VM with array-backed operand stack
- Call frames with base pointer for locals
- Direct opcode dispatch via pattern match
- Zero allocation per step (unlike CEK machine's dict-per-step)
- Handles: constants, variables, jumps, calls, primitives,
collections, string concat, define
Architecture: compiler.sx is spec (SX, portable). VM is platform
(OCaml-native). Same bytecode runs on JS/WASM VMs.
Also includes: CekFrame record optimization in transpiler.sx
(29 frame types as records instead of Hashtbl).
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
This commit is contained in:
235
hosts/ocaml/lib/sx_vm.ml
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235
hosts/ocaml/lib/sx_vm.ml
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@@ -0,0 +1,235 @@
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(** SX bytecode VM — stack-based interpreter.
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Executes bytecode produced by compiler.sx.
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Designed for speed: array-based stack, direct dispatch,
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no allocation per step (unlike the CEK machine).
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This is the platform-native execution engine. The same bytecode
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runs on all platforms (OCaml, JS, WASM). *)
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open Sx_types
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(** Bytecode instruction stream. *)
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type bytecode = int array
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(** Code object — compiled function body. *)
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type code = {
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arity : int;
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locals : int;
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bytecode : bytecode;
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constants : value array;
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}
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(** Upvalue — reference to a captured variable. *)
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type upvalue_ref =
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| Open of int (* index into enclosing frame's locals *)
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| Closed of value ref (* heap-allocated after frame returns *)
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(** Closure — code + captured upvalues. *)
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type closure = {
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code : code;
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upvalues : upvalue_ref array;
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name : string option;
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}
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(** Call frame — one per function invocation. *)
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type frame = {
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closure : closure;
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mutable ip : int;
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base : int; (* base index in value stack *)
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}
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(** VM state. *)
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type vm = {
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mutable stack : value array;
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mutable sp : int; (* stack pointer — next free slot *)
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mutable frames : frame list;
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globals : (string, value) Hashtbl.t;
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}
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(** Create a new VM. *)
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let create () = {
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stack = Array.make 1024 Nil;
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sp = 0;
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frames = [];
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globals = Hashtbl.create 256;
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}
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(** Stack operations. *)
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let push vm v =
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if vm.sp >= Array.length vm.stack then begin
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let new_stack = Array.make (vm.sp * 2) Nil in
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Array.blit vm.stack 0 new_stack 0 vm.sp;
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vm.stack <- new_stack
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end;
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vm.stack.(vm.sp) <- v;
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vm.sp <- vm.sp + 1
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let pop vm =
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vm.sp <- vm.sp - 1;
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vm.stack.(vm.sp)
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let peek vm =
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vm.stack.(vm.sp - 1)
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(** Read operands from bytecode. *)
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let read_u8 frame =
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let v = frame.closure.code.bytecode.(frame.ip) in
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frame.ip <- frame.ip + 1; v
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let read_u16 frame =
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let lo = frame.closure.code.bytecode.(frame.ip) in
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let hi = frame.closure.code.bytecode.(frame.ip + 1) in
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frame.ip <- frame.ip + 2;
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lo lor (hi lsl 8)
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let read_i16 frame =
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let v = read_u16 frame in
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if v >= 32768 then v - 65536 else v
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(** Execute bytecode until OP_RETURN. *)
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let rec run vm =
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match vm.frames with
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| [] -> failwith "VM: no frame"
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| frame :: _ ->
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let code = frame.closure.code in
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let bc = code.bytecode in
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let op = bc.(frame.ip) in
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frame.ip <- frame.ip + 1;
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match op with
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(* ---- Stack / Constants ---- *)
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| 0x01 -> (* OP_CONST *)
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let idx = read_u16 frame in
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push vm code.constants.(idx);
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run vm
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| 0x02 -> push vm Nil; run vm (* OP_NIL *)
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| 0x03 -> push vm (Bool true); run vm (* OP_TRUE *)
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| 0x04 -> push vm (Bool false); run vm (* OP_FALSE *)
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| 0x05 -> ignore (pop vm); run vm (* OP_POP *)
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| 0x06 -> push vm (peek vm); run vm (* OP_DUP *)
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(* ---- Variable access ---- *)
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| 0x10 -> (* OP_LOCAL_GET *)
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let slot = read_u8 frame in
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push vm vm.stack.(frame.base + slot);
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run vm
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| 0x11 -> (* OP_LOCAL_SET *)
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let slot = read_u8 frame in
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vm.stack.(frame.base + slot) <- peek vm;
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run vm
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| 0x14 -> (* OP_GLOBAL_GET *)
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let idx = read_u16 frame in
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let name = match code.constants.(idx) with String s -> s | _ -> "" in
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let v = try Hashtbl.find vm.globals name with Not_found ->
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(* Fall back to primitives *)
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try Sx_primitives.get name
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with _ -> raise (Eval_error ("Undefined: " ^ name))
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in
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push vm v; run vm
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| 0x15 -> (* OP_GLOBAL_SET *)
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let idx = read_u16 frame in
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let name = match code.constants.(idx) with String s -> s | _ -> "" in
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Hashtbl.replace vm.globals name (peek vm);
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run vm
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(* ---- Control flow ---- *)
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| 0x20 -> (* OP_JUMP *)
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let offset = read_i16 frame in
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frame.ip <- frame.ip + offset;
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run vm
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| 0x21 -> (* OP_JUMP_IF_FALSE *)
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let offset = read_i16 frame in
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let v = pop vm in
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if not (sx_truthy v) then frame.ip <- frame.ip + offset;
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run vm
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| 0x22 -> (* OP_JUMP_IF_TRUE *)
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let offset = read_i16 frame in
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let v = pop vm in
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if sx_truthy v then frame.ip <- frame.ip + offset;
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run vm
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(* ---- Function calls ---- *)
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| 0x30 -> (* OP_CALL *)
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let argc = read_u8 frame in
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let args = Array.init argc (fun _ -> pop vm) in
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let f = pop vm in
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call vm f (Array.to_list (Array.of_list (List.rev (Array.to_list args))));
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run vm
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| 0x31 -> (* OP_TAIL_CALL *)
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let argc = read_u8 frame in
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let args = Array.init argc (fun _ -> pop vm) in
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let _f = pop vm in
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(* TODO: tail call optimization — reuse frame *)
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let args_list = List.rev (Array.to_list args) in
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call vm _f args_list;
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run vm
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| 0x32 -> (* OP_RETURN *)
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let result = pop vm in
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vm.frames <- List.tl vm.frames;
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vm.sp <- frame.base;
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push vm result
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(* Don't recurse — return to caller *)
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| 0x34 -> (* OP_CALL_PRIM *)
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let idx = read_u16 frame in
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let argc = read_u8 frame in
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let name = match code.constants.(idx) with String s -> s | _ -> "" in
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let args = List.init argc (fun _ -> pop vm) |> List.rev in
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let result = Sx_primitives.call name args in
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push vm result;
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run vm
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(* ---- Collections ---- *)
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| 0x40 -> (* OP_LIST *)
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let count = read_u16 frame in
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let items = List.init count (fun _ -> pop vm) |> List.rev in
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push vm (List items);
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run vm
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| 0x41 -> (* OP_DICT *)
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let count = read_u16 frame in
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let d = Hashtbl.create count in
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for _ = 1 to count do
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let v = pop vm in
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let k = pop vm in
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let key = match k with String s -> s | Keyword s -> s | _ -> "" in
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Hashtbl.replace d key v
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done;
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push vm (Dict d);
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run vm
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(* ---- String ops ---- *)
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| 0x90 -> (* OP_STR_CONCAT *)
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let count = read_u8 frame in
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let parts = List.init count (fun _ -> pop vm) |> List.rev in
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let s = String.concat "" (List.map value_to_str parts) in
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push vm (String s);
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run vm
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(* ---- Define ---- *)
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| 0x80 -> (* OP_DEFINE *)
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let idx = read_u16 frame in
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let name = match code.constants.(idx) with String s -> s | _ -> "" in
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let v = peek vm in
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Hashtbl.replace vm.globals name v;
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run vm
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| opcode ->
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raise (Eval_error (Printf.sprintf "VM: unknown opcode 0x%02x at ip=%d" opcode (frame.ip - 1)))
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and call vm f args =
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match f with
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| NativeFn (_, fn) ->
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let result = fn args in
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push vm result
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| _ ->
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raise (Eval_error ("VM: not callable: " ^ value_to_str f))
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(** Execute a code object in a fresh VM. *)
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let execute code globals =
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let vm = create () in
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(* Copy globals *)
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Hashtbl.iter (fun k v -> Hashtbl.replace vm.globals k v) globals;
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let closure = { code; upvalues = [||]; name = None } in
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let frame = { closure; ip = 0; base = 0 } in
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vm.frames <- [frame];
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run vm;
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pop vm
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146
spec/bytecode.sx
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146
spec/bytecode.sx
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@@ -0,0 +1,146 @@
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;; ==========================================================================
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;; bytecode.sx — SX bytecode format definition
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;;
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;; Universal bytecode for SX evaluation. Produced by compiler.sx,
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;; executed by platform-native VMs (OCaml, JS, WASM).
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;;
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;; Design principles:
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;; - One byte per opcode (~65 ops, fits in u8)
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;; - Variable-length encoding (1-5 bytes per instruction)
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;; - Lexical scope resolved at compile time (no hash lookups)
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;; - Tail calls detected statically (no thunks/trampoline)
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;; - Control flow via jumps (no continuation frames for if/when/etc.)
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;; - Content-addressable (deterministic binary for CID)
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;; ==========================================================================
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;; --------------------------------------------------------------------------
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;; Opcode constants
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;; --------------------------------------------------------------------------
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;; Stack / Constants
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(define OP_CONST 0x01) ;; u16 pool_idx — push constant
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(define OP_NIL 0x02) ;; push nil
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(define OP_TRUE 0x03) ;; push true
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(define OP_FALSE 0x04) ;; push false
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(define OP_POP 0x05) ;; discard TOS
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(define OP_DUP 0x06) ;; duplicate TOS
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;; Variable access (resolved at compile time)
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(define OP_LOCAL_GET 0x10) ;; u8 slot
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(define OP_LOCAL_SET 0x11) ;; u8 slot
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(define OP_UPVALUE_GET 0x12) ;; u8 idx
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(define OP_UPVALUE_SET 0x13) ;; u8 idx
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(define OP_GLOBAL_GET 0x14) ;; u16 name_idx
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(define OP_GLOBAL_SET 0x15) ;; u16 name_idx
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;; Control flow (replaces if/when/cond/and/or frames)
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(define OP_JUMP 0x20) ;; i16 offset
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(define OP_JUMP_IF_FALSE 0x21) ;; i16 offset
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(define OP_JUMP_IF_TRUE 0x22) ;; i16 offset
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;; Function operations
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(define OP_CALL 0x30) ;; u8 argc
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(define OP_TAIL_CALL 0x31) ;; u8 argc — reuse frame (TCO)
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(define OP_RETURN 0x32) ;; return TOS
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(define OP_CLOSURE 0x33) ;; u16 code_idx — create closure
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(define OP_CALL_PRIM 0x34) ;; u16 name_idx, u8 argc — direct primitive
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(define OP_APPLY 0x35) ;; (apply f args-list)
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;; Collection construction
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(define OP_LIST 0x40) ;; u16 count — build list from stack
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(define OP_DICT 0x41) ;; u16 count — build dict from stack pairs
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(define OP_APPEND_BANG 0x42) ;; (append! TOS-1 TOS)
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;; Higher-order forms (inlined loop)
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(define OP_ITER_INIT 0x50) ;; init iterator on TOS list
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(define OP_ITER_NEXT 0x51) ;; i16 end_offset — push next or jump
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(define OP_MAP_OPEN 0x52) ;; push empty accumulator
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(define OP_MAP_APPEND 0x53) ;; append TOS to accumulator
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(define OP_MAP_CLOSE 0x54) ;; pop accumulator as list
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(define OP_FILTER_TEST 0x55) ;; i16 skip — if falsy jump (skip append)
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;; HO fallback (dynamic callback)
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(define OP_HO_MAP 0x58) ;; (map fn coll)
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(define OP_HO_FILTER 0x59) ;; (filter fn coll)
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(define OP_HO_REDUCE 0x5A) ;; (reduce fn init coll)
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(define OP_HO_FOR_EACH 0x5B) ;; (for-each fn coll)
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(define OP_HO_SOME 0x5C) ;; (some fn coll)
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(define OP_HO_EVERY 0x5D) ;; (every? fn coll)
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;; Scope / dynamic binding
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(define OP_SCOPE_PUSH 0x60) ;; TOS = name
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(define OP_SCOPE_POP 0x61)
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(define OP_PROVIDE_PUSH 0x62) ;; TOS-1 = name, TOS = value
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(define OP_PROVIDE_POP 0x63)
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(define OP_CONTEXT 0x64) ;; TOS = name → push value
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(define OP_EMIT 0x65) ;; TOS-1 = name, TOS = value
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(define OP_EMITTED 0x66) ;; TOS = name → push collected
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;; Continuations
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(define OP_RESET 0x70) ;; i16 body_len — push delimiter
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(define OP_SHIFT 0x71) ;; u8 k_slot, i16 body_len — capture k
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;; Define / component
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(define OP_DEFINE 0x80) ;; u16 name_idx — bind TOS to name
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(define OP_DEFCOMP 0x81) ;; u16 template_idx
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(define OP_DEFISLAND 0x82) ;; u16 template_idx
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(define OP_DEFMACRO 0x83) ;; u16 template_idx
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(define OP_EXPAND_MACRO 0x84) ;; u8 argc — runtime macro expansion
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;; String / serialize (hot path)
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(define OP_STR_CONCAT 0x90) ;; u8 count — concat N values as strings
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(define OP_STR_JOIN 0x91) ;; (join sep list)
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(define OP_SERIALIZE 0x92) ;; serialize TOS to SX string
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;; Aser specialization (optional, 0xE0-0xEF reserved)
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(define OP_ASER_TAG 0xE0) ;; u16 tag_name_idx — serialize HTML tag
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(define OP_ASER_FRAG 0xE1) ;; u8 child_count — serialize fragment
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;; --------------------------------------------------------------------------
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;; Bytecode module structure
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;; --------------------------------------------------------------------------
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;; A module contains:
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;; magic: "SXBC" (4 bytes)
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;; version: u16
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;; pool_count: u32
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;; pool: constant pool entries (self-describing tagged values)
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;; code_count: u32
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;; codes: code objects
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;; entry: u32 (index of entry-point code object)
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(define BYTECODE_MAGIC "SXBC")
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(define BYTECODE_VERSION 1)
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;; Constant pool tags
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(define CONST_NUMBER 0x01)
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(define CONST_STRING 0x02)
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(define CONST_BOOL 0x03)
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(define CONST_NIL 0x04)
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(define CONST_SYMBOL 0x05)
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(define CONST_KEYWORD 0x06)
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(define CONST_LIST 0x07)
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(define CONST_DICT 0x08)
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(define CONST_CODE 0x09)
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;; --------------------------------------------------------------------------
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;; Disassembler
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;; --------------------------------------------------------------------------
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(define opcode-names
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{:0x01 "CONST" :0x02 "NIL" :0x03 "TRUE" :0x04 "FALSE"
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:0x05 "POP" :0x06 "DUP"
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:0x10 "LOCAL_GET" :0x11 "LOCAL_SET"
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:0x12 "UPVALUE_GET" :0x13 "UPVALUE_SET"
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:0x14 "GLOBAL_GET" :0x15 "GLOBAL_SET"
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:0x20 "JUMP" :0x21 "JUMP_IF_FALSE" :0x22 "JUMP_IF_TRUE"
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:0x30 "CALL" :0x31 "TAIL_CALL" :0x32 "RETURN"
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:0x33 "CLOSURE" :0x34 "CALL_PRIM" :0x35 "APPLY"
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:0x40 "LIST" :0x41 "DICT" :0x42 "APPEND!"
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:0x50 "ITER_INIT" :0x51 "ITER_NEXT"
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:0x52 "MAP_OPEN" :0x53 "MAP_APPEND" :0x54 "MAP_CLOSE"
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:0x80 "DEFINE" :0x90 "STR_CONCAT" :0x92 "SERIALIZE"
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:0xE0 "ASER_TAG" :0xE1 "ASER_FRAG"})
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484
spec/compiler.sx
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484
spec/compiler.sx
Normal file
@@ -0,0 +1,484 @@
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;; ==========================================================================
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;; compiler.sx — SX bytecode compiler
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;;
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;; Compiles SX AST to bytecode for the platform-native VM.
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;; Written in SX — runs on any platform with an SX evaluator.
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;;
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;; Architecture:
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;; Pass 1: Scope analysis — resolve variables, detect tail positions
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;; Pass 2: Code generation — emit bytecode
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;;
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;; The compiler produces Code objects (bytecode + constant pool).
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;; The VM executes them with a stack machine model.
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;; ==========================================================================
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;; --------------------------------------------------------------------------
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;; Constant pool builder
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;; --------------------------------------------------------------------------
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(define make-pool
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(fn ()
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{:entries (list)
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:index {:_count 0}}))
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(define pool-add
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(fn (pool value)
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"Add a value to the constant pool, return its index. Deduplicates."
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(let ((key (serialize value))
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(idx-map (get pool "index")))
|
||||
(if (has-key? idx-map key)
|
||||
(get idx-map key)
|
||||
(let ((idx (get idx-map "_count")))
|
||||
(dict-set! idx-map key idx)
|
||||
(dict-set! idx-map "_count" (+ idx 1))
|
||||
(append! (get pool "entries") value)
|
||||
idx)))))
|
||||
|
||||
|
||||
;; --------------------------------------------------------------------------
|
||||
;; Scope analysis
|
||||
;; --------------------------------------------------------------------------
|
||||
|
||||
(define make-scope
|
||||
(fn (parent)
|
||||
{:locals (list) ;; list of {name, slot, mutable?}
|
||||
:upvalues (list) ;; list of {name, is-local, index}
|
||||
:parent parent
|
||||
:next-slot 0}))
|
||||
|
||||
(define scope-define-local
|
||||
(fn (scope name)
|
||||
"Add a local variable, return its slot index."
|
||||
(let ((slot (get scope "next-slot")))
|
||||
(append! (get scope "locals")
|
||||
{:name name :slot slot :mutable false})
|
||||
(dict-set! scope "next-slot" (+ slot 1))
|
||||
slot)))
|
||||
|
||||
(define scope-resolve
|
||||
(fn (scope name)
|
||||
"Resolve a variable name. Returns {:type \"local\"|\"upvalue\"|\"global\", :index N}."
|
||||
(if (nil? scope)
|
||||
{:type "global" :index name}
|
||||
;; Check locals
|
||||
(let ((locals (get scope "locals"))
|
||||
(found (some (fn (l) (= (get l "name") name)) locals)))
|
||||
(if found
|
||||
(let ((local (first (filter (fn (l) (= (get l "name") name)) locals))))
|
||||
{:type "local" :index (get local "slot")})
|
||||
;; Check upvalues (already captured)
|
||||
(let ((upvals (get scope "upvalues"))
|
||||
(uv-found (some (fn (u) (= (get u "name") name)) upvals)))
|
||||
(if uv-found
|
||||
(let ((uv (first (filter (fn (u) (= (get u "name") name)) upvals))))
|
||||
{:type "upvalue" :index (get uv "index")})
|
||||
;; Try parent scope — if found, capture as upvalue
|
||||
(let ((parent-result (scope-resolve (get scope "parent") name)))
|
||||
(if (= (get parent-result "type") "global")
|
||||
parent-result
|
||||
;; Capture from parent as upvalue
|
||||
(let ((uv-idx (len (get scope "upvalues"))))
|
||||
(append! (get scope "upvalues")
|
||||
{:name name
|
||||
:is-local (= (get parent-result "type") "local")
|
||||
:index (get parent-result "index")})
|
||||
{:type "upvalue" :index uv-idx}))))))))))
|
||||
|
||||
|
||||
;; --------------------------------------------------------------------------
|
||||
;; Code emitter
|
||||
;; --------------------------------------------------------------------------
|
||||
|
||||
(define make-emitter
|
||||
(fn ()
|
||||
{:bytecode (list) ;; list of bytes
|
||||
:pool (make-pool)}))
|
||||
|
||||
(define emit-byte
|
||||
(fn (em byte)
|
||||
(append! (get em "bytecode") byte)))
|
||||
|
||||
(define emit-u16
|
||||
(fn (em value)
|
||||
(emit-byte em (mod value 256))
|
||||
(emit-byte em (mod (floor (/ value 256)) 256))))
|
||||
|
||||
(define emit-i16
|
||||
(fn (em value)
|
||||
(let ((v (if (< value 0) (+ value 65536) value)))
|
||||
(emit-u16 em v))))
|
||||
|
||||
(define emit-op
|
||||
(fn (em opcode)
|
||||
(emit-byte em opcode)))
|
||||
|
||||
(define emit-const
|
||||
(fn (em value)
|
||||
(let ((idx (pool-add (get em "pool") value)))
|
||||
(emit-op em 0x01) ;; OP_CONST
|
||||
(emit-u16 em idx))))
|
||||
|
||||
(define current-offset
|
||||
(fn (em)
|
||||
(len (get em "bytecode"))))
|
||||
|
||||
(define patch-i16
|
||||
(fn (em offset value)
|
||||
"Patch a previously emitted i16 at the given bytecode offset."
|
||||
(let ((v (if (< value 0) (+ value 65536) value))
|
||||
(bc (get em "bytecode")))
|
||||
;; Direct mutation of bytecode list at offset
|
||||
(set-nth! bc offset (mod v 256))
|
||||
(set-nth! bc (+ offset 1) (mod (floor (/ v 256)) 256)))))
|
||||
|
||||
|
||||
;; --------------------------------------------------------------------------
|
||||
;; Compilation — expression dispatch
|
||||
;; --------------------------------------------------------------------------
|
||||
|
||||
(define compile-expr
|
||||
(fn (em expr scope tail?)
|
||||
"Compile an expression. tail? indicates tail position for TCO."
|
||||
(cond
|
||||
;; Nil
|
||||
(nil? expr)
|
||||
(emit-op em 0x02) ;; OP_NIL
|
||||
|
||||
;; Number
|
||||
(= (type-of expr) "number")
|
||||
(emit-const em expr)
|
||||
|
||||
;; String
|
||||
(= (type-of expr) "string")
|
||||
(emit-const em expr)
|
||||
|
||||
;; Boolean
|
||||
(= (type-of expr) "boolean")
|
||||
(emit-op em (if expr 0x03 0x04)) ;; OP_TRUE / OP_FALSE
|
||||
|
||||
;; Keyword
|
||||
(= (type-of expr) "keyword")
|
||||
(emit-const em (keyword-name expr))
|
||||
|
||||
;; Symbol — resolve to local/upvalue/global
|
||||
(= (type-of expr) "symbol")
|
||||
(compile-symbol em (symbol-name expr) scope)
|
||||
|
||||
;; List — dispatch on head
|
||||
(= (type-of expr) "list")
|
||||
(if (empty? expr)
|
||||
(do (emit-op em 0x40) (emit-u16 em 0)) ;; OP_LIST 0
|
||||
(compile-list em expr scope tail?))
|
||||
|
||||
;; Dict literal
|
||||
(= (type-of expr) "dict")
|
||||
(compile-dict em expr scope)
|
||||
|
||||
;; Fallback
|
||||
:else
|
||||
(emit-const em expr))))
|
||||
|
||||
|
||||
(define compile-symbol
|
||||
(fn (em name scope)
|
||||
(let ((resolved (scope-resolve scope name)))
|
||||
(cond
|
||||
(= (get resolved "type") "local")
|
||||
(do (emit-op em 0x10) ;; OP_LOCAL_GET
|
||||
(emit-byte em (get resolved "index")))
|
||||
(= (get resolved "type") "upvalue")
|
||||
(do (emit-op em 0x12) ;; OP_UPVALUE_GET
|
||||
(emit-byte em (get resolved "index")))
|
||||
:else
|
||||
;; Global or primitive
|
||||
(let ((idx (pool-add (get em "pool") name)))
|
||||
(emit-op em 0x14) ;; OP_GLOBAL_GET
|
||||
(emit-u16 em idx))))))
|
||||
|
||||
|
||||
(define compile-dict
|
||||
(fn (em expr scope)
|
||||
(let ((ks (keys expr))
|
||||
(count (len ks)))
|
||||
(for-each (fn (k)
|
||||
(emit-const em k)
|
||||
(compile-expr em (get expr k) scope false))
|
||||
ks)
|
||||
(emit-op em 0x41) ;; OP_DICT
|
||||
(emit-u16 em count))))
|
||||
|
||||
|
||||
;; --------------------------------------------------------------------------
|
||||
;; List compilation — special forms, calls
|
||||
;; --------------------------------------------------------------------------
|
||||
|
||||
(define compile-list
|
||||
(fn (em expr scope tail?)
|
||||
(let ((head (first expr))
|
||||
(args (rest expr)))
|
||||
(if (not (= (type-of head) "symbol"))
|
||||
;; Non-symbol head — compile as call
|
||||
(compile-call em head args scope tail?)
|
||||
;; Symbol head — check for special forms
|
||||
(let ((name (symbol-name head)))
|
||||
(cond
|
||||
(= name "if") (compile-if em args scope tail?)
|
||||
(= name "when") (compile-when em args scope tail?)
|
||||
(= name "and") (compile-and em args scope tail?)
|
||||
(= name "or") (compile-or em args scope tail?)
|
||||
(= name "let") (compile-let em args scope tail?)
|
||||
(= name "let*") (compile-let em args scope tail?)
|
||||
(= name "begin") (compile-begin em args scope tail?)
|
||||
(= name "do") (compile-begin em args scope tail?)
|
||||
(= name "lambda") (compile-lambda em args scope)
|
||||
(= name "fn") (compile-lambda em args scope)
|
||||
(= name "define") (compile-define em args scope)
|
||||
(= name "set!") (compile-set em args scope)
|
||||
(= name "quote") (compile-quote em args)
|
||||
(= name "if") (compile-if em args scope tail?)
|
||||
;; Default — function call
|
||||
:else
|
||||
(compile-call em head args scope tail?)))))))
|
||||
|
||||
|
||||
;; --------------------------------------------------------------------------
|
||||
;; Special form compilation
|
||||
;; --------------------------------------------------------------------------
|
||||
|
||||
(define compile-if
|
||||
(fn (em args scope tail?)
|
||||
(let ((test (first args))
|
||||
(then-expr (nth args 1))
|
||||
(else-expr (if (> (len args) 2) (nth args 2) nil)))
|
||||
;; Compile test
|
||||
(compile-expr em test scope false)
|
||||
;; Jump if false to else
|
||||
(emit-op em 0x21) ;; OP_JUMP_IF_FALSE
|
||||
(let ((else-jump (current-offset em)))
|
||||
(emit-i16 em 0) ;; placeholder
|
||||
;; Compile then (in tail position if if is)
|
||||
(compile-expr em then-expr scope tail?)
|
||||
;; Jump over else
|
||||
(emit-op em 0x20) ;; OP_JUMP
|
||||
(let ((end-jump (current-offset em)))
|
||||
(emit-i16 em 0) ;; placeholder
|
||||
;; Patch else jump
|
||||
(patch-i16 em else-jump (- (current-offset em) else-jump -2))
|
||||
;; Compile else
|
||||
(if (nil? else-expr)
|
||||
(emit-op em 0x02) ;; OP_NIL
|
||||
(compile-expr em else-expr scope tail?))
|
||||
;; Patch end jump
|
||||
(patch-i16 em end-jump (- (current-offset em) end-jump -2)))))))
|
||||
|
||||
|
||||
(define compile-when
|
||||
(fn (em args scope tail?)
|
||||
(let ((test (first args))
|
||||
(body (rest args)))
|
||||
(compile-expr em test scope false)
|
||||
(emit-op em 0x21) ;; OP_JUMP_IF_FALSE
|
||||
(let ((skip-jump (current-offset em)))
|
||||
(emit-i16 em 0)
|
||||
(compile-begin em body scope tail?)
|
||||
(emit-op em 0x20) ;; OP_JUMP
|
||||
(let ((end-jump (current-offset em)))
|
||||
(emit-i16 em 0)
|
||||
(patch-i16 em skip-jump (- (current-offset em) skip-jump -2))
|
||||
(emit-op em 0x02) ;; OP_NIL
|
||||
(patch-i16 em end-jump (- (current-offset em) end-jump -2)))))))
|
||||
|
||||
|
||||
(define compile-and
|
||||
(fn (em args scope tail?)
|
||||
(if (empty? args)
|
||||
(emit-op em 0x03) ;; OP_TRUE
|
||||
(if (= (len args) 1)
|
||||
(compile-expr em (first args) scope tail?)
|
||||
(do
|
||||
(compile-expr em (first args) scope false)
|
||||
(emit-op em 0x06) ;; OP_DUP
|
||||
(emit-op em 0x21) ;; OP_JUMP_IF_FALSE
|
||||
(let ((skip (current-offset em)))
|
||||
(emit-i16 em 0)
|
||||
(emit-op em 0x05) ;; OP_POP (discard duplicated truthy)
|
||||
(compile-and em (rest args) scope tail?)
|
||||
(patch-i16 em skip (- (current-offset em) skip -2))))))))
|
||||
|
||||
|
||||
(define compile-or
|
||||
(fn (em args scope tail?)
|
||||
(if (empty? args)
|
||||
(emit-op em 0x04) ;; OP_FALSE
|
||||
(if (= (len args) 1)
|
||||
(compile-expr em (first args) scope tail?)
|
||||
(do
|
||||
(compile-expr em (first args) scope false)
|
||||
(emit-op em 0x06) ;; OP_DUP
|
||||
(emit-op em 0x22) ;; OP_JUMP_IF_TRUE
|
||||
(let ((skip (current-offset em)))
|
||||
(emit-i16 em 0)
|
||||
(emit-op em 0x05) ;; OP_POP
|
||||
(compile-or em (rest args) scope tail?)
|
||||
(patch-i16 em skip (- (current-offset em) skip -2))))))))
|
||||
|
||||
|
||||
(define compile-begin
|
||||
(fn (em exprs scope tail?)
|
||||
(if (empty? exprs)
|
||||
(emit-op em 0x02) ;; OP_NIL
|
||||
(if (= (len exprs) 1)
|
||||
(compile-expr em (first exprs) scope tail?)
|
||||
(do
|
||||
(compile-expr em (first exprs) scope false)
|
||||
(emit-op em 0x05) ;; OP_POP
|
||||
(compile-begin em (rest exprs) scope tail?))))))
|
||||
|
||||
|
||||
(define compile-let
|
||||
(fn (em args scope tail?)
|
||||
(let ((bindings (first args))
|
||||
(body (rest args))
|
||||
(let-scope (make-scope scope)))
|
||||
;; Compile each binding
|
||||
(for-each (fn (binding)
|
||||
(let ((name (if (= (type-of (first binding)) "symbol")
|
||||
(symbol-name (first binding))
|
||||
(first binding)))
|
||||
(value (nth binding 1))
|
||||
(slot (scope-define-local let-scope name)))
|
||||
(compile-expr em value let-scope false)
|
||||
(emit-op em 0x11) ;; OP_LOCAL_SET
|
||||
(emit-byte em slot)))
|
||||
bindings)
|
||||
;; Compile body in let scope
|
||||
(compile-begin em body let-scope tail?))))
|
||||
|
||||
|
||||
(define compile-lambda
|
||||
(fn (em args scope)
|
||||
(let ((params (first args))
|
||||
(body (rest args))
|
||||
(fn-scope (make-scope scope))
|
||||
(fn-em (make-emitter)))
|
||||
;; Define params as locals in fn scope
|
||||
(for-each (fn (p)
|
||||
(let ((name (if (= (type-of p) "symbol") (symbol-name p) p)))
|
||||
(when (and (not (= name "&key"))
|
||||
(not (= name "&rest")))
|
||||
(scope-define-local fn-scope name))))
|
||||
params)
|
||||
;; Compile body
|
||||
(compile-begin fn-em body fn-scope true) ;; tail position
|
||||
(emit-op fn-em 0x32) ;; OP_RETURN
|
||||
;; Add code object to parent constant pool
|
||||
(let ((code {:arity (len (get fn-scope "locals"))
|
||||
:bytecode (get fn-em "bytecode")
|
||||
:pool (get fn-em "pool")
|
||||
:upvalues (get fn-scope "upvalues")})
|
||||
(code-idx (pool-add (get em "pool") code)))
|
||||
(emit-op em 0x33) ;; OP_CLOSURE
|
||||
(emit-u16 em code-idx)))))
|
||||
|
||||
|
||||
(define compile-define
|
||||
(fn (em args scope)
|
||||
(let ((name-expr (first args))
|
||||
(name (if (= (type-of name-expr) "symbol")
|
||||
(symbol-name name-expr)
|
||||
name-expr))
|
||||
(value (nth args 1))
|
||||
(name-idx (pool-add (get em "pool") name)))
|
||||
(compile-expr em value scope false)
|
||||
(emit-op em 0x80) ;; OP_DEFINE
|
||||
(emit-u16 em name-idx))))
|
||||
|
||||
|
||||
(define compile-set
|
||||
(fn (em args scope)
|
||||
(let ((name (if (= (type-of (first args)) "symbol")
|
||||
(symbol-name (first args))
|
||||
(first args)))
|
||||
(value (nth args 1))
|
||||
(resolved (scope-resolve scope name)))
|
||||
(compile-expr em value scope false)
|
||||
(cond
|
||||
(= (get resolved "type") "local")
|
||||
(do (emit-op em 0x11) ;; OP_LOCAL_SET
|
||||
(emit-byte em (get resolved "index")))
|
||||
(= (get resolved "type") "upvalue")
|
||||
(do (emit-op em 0x13) ;; OP_UPVALUE_SET
|
||||
(emit-byte em (get resolved "index")))
|
||||
:else
|
||||
(let ((idx (pool-add (get em "pool") name)))
|
||||
(emit-op em 0x15) ;; OP_GLOBAL_SET
|
||||
(emit-u16 em idx))))))
|
||||
|
||||
|
||||
(define compile-quote
|
||||
(fn (em args)
|
||||
(if (empty? args)
|
||||
(emit-op em 0x02) ;; OP_NIL
|
||||
(emit-const em (first args)))))
|
||||
|
||||
|
||||
;; --------------------------------------------------------------------------
|
||||
;; Function call compilation
|
||||
;; --------------------------------------------------------------------------
|
||||
|
||||
(define compile-call
|
||||
(fn (em head args scope tail?)
|
||||
;; Check for known primitives
|
||||
(let ((is-prim (and (= (type-of head) "symbol")
|
||||
(let ((name (symbol-name head)))
|
||||
(and (not (= (get (scope-resolve scope name) "type") "local"))
|
||||
(not (= (get (scope-resolve scope name) "type") "upvalue"))
|
||||
(primitive? name))))))
|
||||
(if is-prim
|
||||
;; Direct primitive call — no closure overhead
|
||||
(let ((name (symbol-name head))
|
||||
(name-idx (pool-add (get em "pool") name)))
|
||||
(for-each (fn (a) (compile-expr em a scope false)) args)
|
||||
(emit-op em 0x34) ;; OP_CALL_PRIM
|
||||
(emit-u16 em name-idx)
|
||||
(emit-byte em (len args)))
|
||||
;; General call
|
||||
(do
|
||||
(compile-expr em head scope false)
|
||||
(for-each (fn (a) (compile-expr em a scope false)) args)
|
||||
(if tail?
|
||||
(do (emit-op em 0x31) ;; OP_TAIL_CALL
|
||||
(emit-byte em (len args)))
|
||||
(do (emit-op em 0x30) ;; OP_CALL
|
||||
(emit-byte em (len args)))))))))
|
||||
|
||||
|
||||
;; --------------------------------------------------------------------------
|
||||
;; Top-level API
|
||||
;; --------------------------------------------------------------------------
|
||||
|
||||
(define compile
|
||||
(fn (expr)
|
||||
"Compile a single SX expression to a bytecode module."
|
||||
(let ((em (make-emitter))
|
||||
(scope (make-scope nil)))
|
||||
(compile-expr em expr scope false)
|
||||
(emit-op em 0x32) ;; OP_RETURN
|
||||
{:bytecode (get em "bytecode")
|
||||
:pool (get em "pool")})))
|
||||
|
||||
(define compile-module
|
||||
(fn (exprs)
|
||||
"Compile a list of top-level expressions to a bytecode module."
|
||||
(let ((em (make-emitter))
|
||||
(scope (make-scope nil)))
|
||||
(for-each (fn (expr)
|
||||
(compile-expr em expr scope false)
|
||||
(emit-op em 0x05)) ;; OP_POP between top-level exprs
|
||||
(init exprs))
|
||||
;; Last expression's value is the module result
|
||||
(compile-expr em (last exprs) scope false)
|
||||
(emit-op em 0x32) ;; OP_RETURN
|
||||
{:bytecode (get em "bytecode")
|
||||
:pool (get em "pool")})))
|
||||
Reference in New Issue
Block a user