guards in mcode

docs/spec/mcode.md

@@ -173,7 +173,6 @@ Memory operations come in typed variants. The compiler selects the appropriate v
 | `store_dynamic` | `obj, val, key` | Store property (dispatches at runtime) |
 | `delete` | `obj, key` | Delete property |
 | `in` | `dest, obj, key` | Check if property exists |
-| `typeof` | `dest, src` | Get type name as text |
 | `length` | `dest, src` | Get length of array or text |
 
 ### Object and Array Construction
@@ -181,7 +180,7 @@ Memory operations come in typed variants. The compiler selects the appropriate v
 | Instruction | Operands | Description |
 |-------------|----------|-------------|
 | `record` | `dest` | Create empty record `{}` |
-| `array` | `dest, n, ...elems` | Create array with `n` elements |
+| `array` | `dest, n` | Create empty array (elements added via `push`) |
 | `push` | `arr, val` | Push value to array |
 | `pop` | `dest, arr` | Pop value from array |
 

mcode.cm

@@ -782,13 +782,12 @@ var mcode = function(ast) {
     var name_str = alloc_slot()
     emit_const_str(name_str, prop)
     var args_arr = alloc_slot()
-    var arr_instr = ["array", args_arr, argc]
+    add_instr(["array", args_arr, 0])
     _i = 0
     while (_i < argc) {
-      push(arr_instr, args[_i])
+      emit_2("push", args_arr, args[_i])
       _i = _i + 1
     }
-    add_instr(arr_instr)
     var pf = alloc_slot()
     emit_3("frame", pf, obj, 2)
     emit_3("setarg", pf, 0, null_slot)
@@ -836,13 +835,12 @@ var mcode = function(ast) {
     var null_slot = alloc_slot()
     emit_const_null(null_slot)
     var args_arr = alloc_slot()
-    var arr_instr = ["array", args_arr, argc]
+    add_instr(["array", args_arr, 0])
     _i = 0
     while (_i < argc) {
-      push(arr_instr, args[_i])
+      emit_2("push", args_arr, args[_i])
       _i = _i + 1
     }
-    add_instr(arr_instr)
     var pf = alloc_slot()
     emit_3("frame", pf, obj, 2)
     emit_3("setarg", pf, 0, null_slot)
@@ -1181,17 +1179,29 @@ var mcode = function(ast) {
     var obj_slot = 0
     var idx_expr = null
     var idx_slot = 0
+    var guard_t = 0
+    var guard_err = null
+    var guard_done = null
 
     if (cop != null) {
       return gen_compound_assign(node, cop)
     }
 
-    // Push syntax: arr[] = val
+    // Push syntax: arr[] = val (guarded)
     if (node.push == true) {
       arr_expr = left.left
       arr_slot = gen_expr(arr_expr, -1)
       val_slot = gen_expr(right, -1)
+      guard_t = alloc_slot()
+      guard_err = gen_label("push_err")
+      guard_done = gen_label("push_done")
+      emit_2("is_array", guard_t, arr_slot)
+      emit_jump_cond("jump_false", guard_t, guard_err)
       emit_2("push", arr_slot, val_slot)
+      emit_jump(guard_done)
+      emit_label(guard_err)
+      emit_0("disrupt")
+      emit_label(guard_done)
       return val_slot
     }
 
@@ -1306,6 +1316,9 @@ var mcode = function(ast) {
     var kname = null
     var func = null
     var func_id = 0
+    var guard_t = 0
+    var guard_err = null
+    var guard_done = null
 
     if (expr == null) {
       return -1
@@ -1343,13 +1356,12 @@ var mcode = function(ast) {
       }
       // Create array from expression results
       arr_slot = alloc_slot()
-      arr_instr = ["array", arr_slot, nexpr]
+      add_instr(["array", arr_slot, 0])
       _i = 0
       while (_i < nexpr) {
-        push(arr_instr, expr_slots[_i])
+        emit_2("push", arr_slot, expr_slots[_i])
         _i = _i + 1
       }
-      add_instr(arr_instr)
       // Load format intrinsic
       fmt_func_slot = find_intrinsic("format")
       if (fmt_func_slot < 0) {
@@ -1546,11 +1558,20 @@ var mcode = function(ast) {
             return d
           }
         }
-        // 2-arg push: push(arr, val) → direct opcode
+        // 2-arg push: push(arr, val) → guarded direct opcode
         if (nargs == 2 && fname == "push") {
           a0 = gen_expr(args_list[0], -1)
           a1 = gen_expr(args_list[1], -1)
+          guard_t = alloc_slot()
+          guard_err = gen_label("push_err")
+          guard_done = gen_label("push_done")
+          emit_2("is_array", guard_t, a0)
+          emit_jump_cond("jump_false", guard_t, guard_err)
           emit_2("push", a0, a1)
+          emit_jump(guard_done)
+          emit_label(guard_err)
+          emit_0("disrupt")
+          emit_label(guard_done)
           return a1
         }
       }
@@ -1732,13 +1753,12 @@ var mcode = function(ast) {
         _i = _i + 1
       }
       dest = alloc_slot()
-      instr = ["array", dest, count]
+      add_instr(["array", dest, 0])
       _i = 0
       while (_i < count) {
-        push(instr, elem_slots[_i])
+        emit_2("push", dest, elem_slots[_i])
         _i = _i + 1
       }
-      push(s_instructions, instr)
       return dest
     }
 
@@ -1856,6 +1876,9 @@ var mcode = function(ast) {
     var func = null
     var func_id = 0
     var dest = 0
+    var guard_t = 0
+    var guard_err = null
+    var guard_done = null
 
     if (stmt == null) {
       return null
@@ -1871,12 +1894,21 @@ var mcode = function(ast) {
       right = stmt.right
       name = left.name
       local_slot = find_var(name)
-      // Pop: var val = arr[]
+      // Pop: var val = arr[] (guarded)
       if (stmt.pop == true && right != null) {
         arr_expr = right.left
         arr_slot = gen_expr(arr_expr, -1)
         if (local_slot >= 0) {
+          guard_t = alloc_slot()
+          guard_err = gen_label("pop_err")
+          guard_done = gen_label("pop_done")
+          emit_2("is_array", guard_t, arr_slot)
+          emit_jump_cond("jump_false", guard_t, guard_err)
           emit_2("pop", local_slot, arr_slot)
+          emit_jump(guard_done)
+          emit_label(guard_err)
+          emit_0("disrupt")
+          emit_label(guard_done)
         }
         return null
       }

source/mach.c

@@ -987,13 +987,9 @@ JSValue JS_CallRegisterVM(JSContext *ctx, JSCodeRegister *code,
     }
 
     case MACH_GETINDEX: {
+      /* R(A) = R(B)[R(C)] — mcode guarantees R(C) is int */
       JSValue obj = frame->slots[b];
-      JSValue idx = frame->slots[c];
+      JSValue val = JS_GetPropertyNumber(ctx, obj, JS_VALUE_GET_INT(frame->slots[c]));
-      JSValue val;
-      if (JS_IsInt(idx))
-        val = JS_GetPropertyNumber(ctx, obj, JS_VALUE_GET_INT(idx));
-      else
-        val = JS_GetProperty(ctx, obj, idx);
       frame = (JSFrameRegister *)JS_VALUE_GET_PTR(frame_ref.val);
       if (JS_IsException(val)) goto disrupt;
       frame->slots[a] = val;
@@ -1001,25 +997,12 @@ JSValue JS_CallRegisterVM(JSContext *ctx, JSCodeRegister *code,
     }
 
     case MACH_SETINDEX: {
-      /* R(A)[R(B)] = R(C) */
+      /* R(A)[R(B)] = R(C) — mcode guarantees R(B) is int */
       JSValue obj = frame->slots[a];
-      JSValue idx = frame->slots[b];
       JSValue val = frame->slots[c];
-      int ret;
+      JSValue r = JS_SetPropertyNumber(ctx, obj, JS_VALUE_GET_INT(frame->slots[b]), val);
-      if (JS_IsInt(idx)) {
-        JSValue r = JS_SetPropertyNumber(ctx, obj, JS_VALUE_GET_INT(idx), val);
-        ret = JS_IsException(r) ? -1 : 0;
-      } else if (mist_is_array(obj)) {
-        JS_ThrowTypeError(ctx, "array index must be a number");
-        ret = -1;
-      } else if (mist_is_record(obj) && !mist_is_text(idx) && !mist_is_record(idx)) {
-        JS_ThrowTypeError(ctx, "object key must be a string or object");
-        ret = -1;
-      } else {
-        ret = JS_SetProperty(ctx, obj, idx, val);
-      }
       frame = (JSFrameRegister *)JS_VALUE_GET_PTR(frame_ref.val);
-      if (ret < 0) goto disrupt;
+      if (JS_IsException(r)) goto disrupt;
       break;
     }
 
@@ -1187,16 +1170,10 @@ JSValue JS_CallRegisterVM(JSContext *ctx, JSCodeRegister *code,
     }
 
     case MACH_NEWARRAY: {
-      int count = b;
       JSValue arr = JS_NewArray(ctx);
       frame = (JSFrameRegister *)JS_VALUE_GET_PTR(frame_ref.val);
       if (JS_IsException(arr)) { goto disrupt; }
-      /* Store array in dest immediately so GC can track it */
       frame->slots[a] = arr;
-      for (int i = 0; i < count; i++) {
-        JS_SetPropertyNumber(ctx, frame->slots[a], i, frame->slots[a + 1 + i]);
-        frame = (JSFrameRegister *)JS_VALUE_GET_PTR(frame_ref.val);
-      }
       break;
     }
 
@@ -1216,14 +1193,9 @@ JSValue JS_CallRegisterVM(JSContext *ctx, JSCodeRegister *code,
     }
 
     case MACH_PUSH: {
-      /* push R(B) onto array R(A) */
+      /* push R(B) onto array R(A) — mcode guarantees R(A) is array */
       JSValue arr = frame->slots[a];
       JSValue val = frame->slots[b];
-      if (!mist_is_array(arr)) {
-        JS_ThrowTypeError(ctx, "cannot push to non-array");
-        frame = (JSFrameRegister *)JS_VALUE_GET_PTR(frame_ref.val);
-        goto disrupt;
-      }
       JSGCRef arr_gc;
       JS_PushGCRef(ctx, &arr_gc);
       arr_gc.val = arr;
@@ -1236,13 +1208,8 @@ JSValue JS_CallRegisterVM(JSContext *ctx, JSCodeRegister *code,
     }
 
     case MACH_POP: {
-      /* R(A) = pop last element from array R(B) */
+      /* R(A) = pop last element from array R(B) — mcode guarantees R(B) is array */
       JSValue arr = frame->slots[b];
-      if (!mist_is_array(arr)) {
-        JS_ThrowTypeError(ctx, "cannot pop from non-array");
-        frame = (JSFrameRegister *)JS_VALUE_GET_PTR(frame_ref.val);
-        goto disrupt;
-      }
       JSValue val = JS_ArrayPop(ctx, arr);
       frame = (JSFrameRegister *)JS_VALUE_GET_PTR(frame_ref.val);
       if (JS_IsException(val)) goto disrupt;
@@ -1594,30 +1561,21 @@ JSValue JS_CallRegisterVM(JSContext *ctx, JSCodeRegister *code,
       break;
     }
     case MACH_LOAD_INDEX: {
+      /* R(A) = R(B)[R(C)] — mcode guarantees R(C) is int */
       JSValue obj = frame->slots[b];
-      JSValue idx = frame->slots[c];
+      JSValue val = JS_GetPropertyNumber(ctx, obj, JS_VALUE_GET_INT(frame->slots[c]));
-      JSValue val;
-      if (JS_IsInt(idx))
-        val = JS_GetPropertyNumber(ctx, obj, JS_VALUE_GET_INT(idx));
-      else
-        val = JS_GetProperty(ctx, obj, idx);
       frame = (JSFrameRegister *)JS_VALUE_GET_PTR(frame_ref.val);
       if (JS_IsException(val)) goto disrupt;
       frame->slots[a] = val;
       break;
     }
     case MACH_STORE_INDEX: {
+      /* R(A)[R(B)] = R(C) — mcode guarantees R(B) is int */
       JSValue obj = frame->slots[a];
-      JSValue idx = frame->slots[b];
       JSValue val = frame->slots[c];
-      int ret;
+      JSValue r = JS_SetPropertyNumber(ctx, obj, JS_VALUE_GET_INT(frame->slots[b]), val);
-      if (JS_IsInt(idx)) {
-        JSValue r = JS_SetPropertyNumber(ctx, obj, JS_VALUE_GET_INT(idx), val);
-        ret = JS_IsException(r) ? -1 : 0;
-      } else
-        ret = JS_SetProperty(ctx, obj, idx, val);
       frame = (JSFrameRegister *)JS_VALUE_GET_PTR(frame_ref.val);
-      if (ret < 0) goto disrupt;
+      if (JS_IsException(r)) goto disrupt;
       break;
     }
     case MACH_LOAD_DYNAMIC: {

streamline.cm

@@ -159,8 +159,6 @@ var streamline = function(ir, log) {
       slot_types[text(instr[1])] = T_FUNCTION
     } else if (op == "length") {
       slot_types[text(instr[1])] = T_INT
-    } else if (op == "typeof") {
-      slot_types[text(instr[1])] = T_TEXT
     } else if (op == "neg_int") {
       slot_types[text(instr[1])] = T_INT
     } else if (op == "neg_float") {

test_guards.ce

@@ -0,0 +1,12 @@
+// Test array guard emission and optimization
+var a = [1, 2, 3]
+push(a, 4)
+var v = a[]
+
+var f = function(arr) {
+  push(arr, 99)
+  var x = arr[]
+  return x
+}
+
+f(a)