ludic/selfhost/emit_intrin.ludic

# emit_intrin.ludic — the low-level intrinsics the self-host source uses, each
# lowered to the same libc/inline IR the C backend emits. Returns a Val via
# g_intrin_val and sets g_intrin_ok when `name` was an intrinsic.

var g_intrin_ok: bool = false

# is `name` a low-level intrinsic? A pure name check, so it can gate dispatch
# without evaluating arguments (which could clobber shared state).
fn is_intrinsic(name: ptr) -> bool {
  if (name == "mem_alloc") or (name == "mem_realloc") { return true }
  if (name == "peek8") or (name == "poke8") { return true }
  if (name == "file_open") or (name == "file_read") or (name == "file_write") { return true }
  if (name == "file_seek") or (name == "file_tell") or (name == "file_close") { return true }
  if (name == "os_argc") or (name == "os_arg") or (name == "os_exit") or (name == "file_stderr") { return true }
  if (name == "file_stdout") { return true }
  if (name == "os_system") or (name == "os_getenv") { return true }
  if (name == "peek32") or (name == "poke32") { return true }
  return false
}
# emit "  <r> = <rest>\n" and return r
fn emit_bind(rest: ptr) -> ptr { let r = nreg();  emit("  ");  emit(r);  emit(" = ");  emit(rest);  emit("\n");  return r }

fn arg_code(e: Node, i: int) -> ptr { let v = emit_expr(e.kids[i]);  return v.code }

fn emit_intrinsic(name: ptr, e: Node) -> Val {
  g_intrin_ok = true
  # ptr_null / ptr_is_null are the `null` literal and `x == null` now.
  if (name == "mem_alloc") {
    let n = arg_code(e, 0)
    let w = emit_bind(`zext i32 {n} to i64`)
    return val(emit_bind(`call ptr @malloc(i64 {w})`), "ptr")
  }
  if (name == "mem_realloc") {
    let p = arg_code(e, 0);  let n = arg_code(e, 1)
    let w = emit_bind(`zext i32 {n} to i64`)
    return val(emit_bind(`call ptr @realloc(ptr {p}, i64 {w})`), "ptr")
  }
  if (name == "peek8") {
    let p = arg_code(e, 0);  let i = arg_code(e, 1)
    let a = emit_gep_i8(p, i)
    let b = emit_bind(`load i8, ptr {a}`)
    return val(emit_bind(`zext i8 {b} to i32`), "int")
  }
  if (name == "poke8") {
    let p = arg_code(e, 0);  let i = arg_code(e, 1);  let v = arg_code(e, 2)
    let a = emit_gep_i8(p, i)
    let t = emit_bind(`trunc i32 {v} to i8`)
    emit("  store i8 ");  emit(t);  emit(", ptr ");  emit(a);  emit("\n")
    return val("0", "void")
  }
  if (name == "file_open") {
    let p = arg_code(e, 0);  let m = arg_code(e, 1)
    return val(emit_bind(`call ptr @fopen(ptr {p}, ptr {m})`), "ptr")
  }
  if (name == "file_read") or (name == "file_write") {
    let f = arg_code(e, 0);  let b = arg_code(e, 1);  let n = arg_code(e, 2)
    let w = emit_bind(`zext i32 {n} to i64`)
    var fn2 = "@fread"
    if (name == "file_write") { fn2 = "@fwrite" }
    let r = emit_bind(`call i64 {fn2}(ptr {b}, i64 1, i64 {w}, ptr {f})`)
    return val(emit_bind(`trunc i64 {r} to i32`), "int")
  }
  if (name == "file_seek") {
    let f = arg_code(e, 0);  let off = arg_code(e, 1);  let wh = arg_code(e, 2)
    let o = emit_bind(`sext i32 {off} to i64`)
    return val(emit_bind(`call i32 @fseek(ptr {f}, i64 {o}, i32 {wh})`), "int")
  }
  if (name == "file_tell") {
    let f = arg_code(e, 0)
    let r = emit_bind(`call i64 @ftell(ptr {f})`)
    return val(emit_bind(`trunc i64 {r} to i32`), "int")
  }
  if (name == "file_close") {
    let f = arg_code(e, 0)
    emit("  call i32 @fclose(ptr ");  emit(f);  emit(")\n")
    return val("0", "void")
  }
  # print_str / print_int are the polymorphic `print(x)` builtin now (emit_call).
  if (name == "os_argc") { return val(emit_bind("load i32, ptr @L_argc"), "int") }
  if (name == "os_arg") {
    let i = arg_code(e, 0)
    let v = emit_bind("load ptr, ptr @L_argv")
    let q = emit_bind(`getelementptr ptr, ptr {v}, i32 {i}`)
    return val(emit_bind(`load ptr, ptr {q}`), "str")
  }
  if (name == "os_exit") {
    let n = arg_code(e, 0)
    emit("  call void @exit(i32 ");  emit(n);  emit(")\n")
    emit("  unreachable\n")
    g_term = true
    return val("0", "void")
  }
  if (name == "file_stderr") { return val(emit_bind("load ptr, ptr @__stderrp"), "ptr") }
  if (name == "file_stdout") { return val(emit_bind("load ptr, ptr @__stdoutp"), "ptr") }
  if (name == "os_system") {
    let c = arg_code(e, 0)
    return val(emit_bind(`call i32 @system(ptr {c})`), "int")
  }
  if (name == "os_getenv") {
    let n = arg_code(e, 0)
    return val(emit_bind(`call ptr @getenv(ptr {n})`), "str")
  }
  # bitwise ops are the operators & | ^ << >> ~ now (see emit_bin / p_mul).
  if (name == "peek32") {
    let p = arg_code(e, 0);  let i = arg_code(e, 1)
    let g = nreg()
    emit("  ");  emit(g);  emit(" = getelementptr inbounds i32, ptr ");  emit(p);  emit(", i32 ");  emit(i);  emit("\n")
    return val(emit_bind(`load i32, ptr {g}`), "int")
  }
  if (name == "poke32") {
    let p = arg_code(e, 0);  let i = arg_code(e, 1);  let v = arg_code(e, 2)
    let g = nreg()
    emit("  ");  emit(g);  emit(" = getelementptr inbounds i32, ptr ");  emit(p);  emit(", i32 ");  emit(i);  emit("\n")
    emit("  store i32 ");  emit(v);  emit(", ptr ");  emit(g);  emit("\n")
    return val("0", "void")
  }
  g_intrin_ok = false
  return val("0", "void")
}