Introducing 'opcode counter' type for 'meta' opcode; replacing 'jmp_down' opcodes that are used as pointers only with 'meta' opcodes of the introduced type.

src/globals.h

@@ -37,7 +37,7 @@ typedef signed long ssize_t;
 /**
  * Constants
  */
-#define JERRY_BITSINBYTE 8
+#define JERRY_BITSINBYTE 8u
 
 /**
  * Error codes

src/libcoreint/opcodes.c

@@ -467,18 +467,15 @@ function_declaration (int_data_t *int_data, /**< interpreter context */
   const bool is_strict = int_data->is_strict;
   const bool is_configurable_bindings = int_data->is_eval_code;
 
-  const opcode_counter_t jmp_down_opcode_idx = (opcode_counter_t) (int_data->pos);
+  const opcode_counter_t function_code_begin_oc = (opcode_counter_t) (int_data->pos + 1);
-  opcode_t jmp_down_opcode = read_opcode (jmp_down_opcode_idx);
-  JERRY_ASSERT (jmp_down_opcode.op_idx == __op__idx_jmp_down);
-  int_data->pos = (opcode_counter_t) (jmp_down_opcode_idx + jmp_down_opcode.data.jmp_down.opcode_count);
 
-  const opcode_counter_t function_code_opcode_idx = (opcode_counter_t) (jmp_down_opcode_idx + 1);
+  int_data->pos = read_meta_opcode_counter (int_data);
 
   ecma_string_t *function_name_string_p = ecma_new_ecma_string_from_lit_index (function_name_lit_idx);
 
   ecma_completion_value_t ret_value = ecma_op_function_declaration (int_data->lex_env_p,
                                                                     function_name_string_p,
-                                                                    function_code_opcode_idx,
+                                                                    function_code_begin_oc,
                                                                     args_names,
                                                                     args_number,
                                                                     is_strict,
@@ -618,12 +615,9 @@ opfunc_func_expr_n (opcode_t opdata, /**< operation data */
 
   fill_params_list (int_data, params_number, params_names);
 
-  const opcode_counter_t jmp_down_opcode_idx = (opcode_counter_t) (int_data->pos);
+  const opcode_counter_t function_code_begin_oc = (opcode_counter_t) (int_data->pos + 1);
-  opcode_t jmp_down_opcode = read_opcode (jmp_down_opcode_idx);
-  JERRY_ASSERT (jmp_down_opcode.op_idx == __op__idx_jmp_down);
-  int_data->pos = (opcode_counter_t) (jmp_down_opcode_idx + jmp_down_opcode.data.jmp_down.opcode_count);
 
-  const opcode_counter_t function_code_opcode_idx = (opcode_counter_t) (jmp_down_opcode_idx + 1);
+  int_data->pos = read_meta_opcode_counter (int_data);
 
   ecma_object_t *scope_p;
   ecma_string_t *function_name_string_p = NULL;
@@ -644,7 +638,7 @@ opfunc_func_expr_n (opcode_t opdata, /**< operation data */
                                                               params_number,
                                                               scope_p,
                                                               is_strict,
-                                                              function_code_opcode_idx);
+                                                              function_code_begin_oc);
 
   ecma_completion_value_t ret_value = set_variable_value (int_data,
                                                           dst_var_idx,
@@ -1752,6 +1746,7 @@ opfunc_meta (opcode_t opdata, /**< operation data */
     case OPCODE_META_TYPE_VARG_PROP_DATA:
     case OPCODE_META_TYPE_VARG_PROP_GETTER:
     case OPCODE_META_TYPE_VARG_PROP_SETTER:
+    case OPCODE_META_TYPE_OPCODE_COUNTER:
     {
       JERRY_UNREACHABLE ();
     }
@@ -1760,6 +1755,40 @@ opfunc_meta (opcode_t opdata, /**< operation data */
   JERRY_UNREACHABLE ();
 } /* opfunc_meta */
 
+/**
+ * Calculate opcode counter from 'meta' opcode's data arguments.
+ *
+ * @return opcode counter
+ */
+opcode_counter_t
+calc_meta_opcode_counter_from_meta_data (const idx_t data_1, /**< first data argument */
+                                         const idx_t data_2) /**< second data argument */
+{
+  opcode_counter_t counter;
+
+  counter = data_1;
+  counter = (opcode_counter_t) (counter << (sizeof (data_2) * JERRY_BITSINBYTE));
+  counter = (opcode_counter_t) (counter | data_2);
+  
+  return counter;
+} /* calc_meta_opcode_counter_from_meta_data */
+
+/**
+ * Read opcode counter from current opcode,
+ * that should be 'meta' opcode of type 'opcode counter'.
+ */
+opcode_counter_t
+read_meta_opcode_counter (int_data_t *int_data) /**< interpreter context */
+{
+  opcode_t meta_opcode = read_opcode (int_data->pos);
+  JERRY_ASSERT (meta_opcode.data.meta.type == OPCODE_META_TYPE_OPCODE_COUNTER);
+
+  const idx_t data_1 = meta_opcode.data.meta.data_1;
+  const idx_t data_2 = meta_opcode.data.meta.data_2;
+
+  return calc_meta_opcode_counter_from_meta_data (data_1, data_2);
+} /* read_meta_opcode_counter */
+
 #define GETOP_DEF_1(a, name, field1) \
         inline opcode_t getop_##name (idx_t arg1) \
         { \

src/libcoreint/opcodes.h

@@ -57,7 +57,8 @@ typedef enum
   OPCODE_META_TYPE_VARG_PROP_DATA, /**< name (lit_idx) and value (var_idx) for a data property descriptor */
   OPCODE_META_TYPE_VARG_PROP_GETTER, /**< name (lit_idx) and getter (var_idx) for an accessor property descriptor */
   OPCODE_META_TYPE_VARG_PROP_SETTER, /**< name (lit_idx) and setter (var_idx) for an accessor property descriptor */
-  OPCODE_META_TYPE_END_WITH /**< end of with statement */
+  OPCODE_META_TYPE_END_WITH, /**< end of with statement */
+  OPCODE_META_TYPE_OPCODE_COUNTER /**< opcode counter */
 } opcode_meta_type;
 
 typedef struct
@@ -72,6 +73,9 @@ typedef struct
   ecma_value_t *regs_p; /**< register variables */
 } int_data_t;
 
+opcode_counter_t calc_meta_opcode_counter_from_meta_data (const idx_t data_1, const idx_t data_2);
+opcode_counter_t read_meta_opcode_counter (int_data_t *int_data);
+
 #define OP_CALLS_AND_ARGS(p, a)                                              \
         p##_2 (a, call_0, lhs, name_lit_idx)                                 \
         p##_3 (a, call_1, lhs, name_lit_idx, arg1_lit_idx)                   \

src/libjsparser/parser.c

@@ -894,6 +894,20 @@ parse_argument_list (argument_list_type alt, idx_t obj)
   return lhs;
 }
 
+static void
+rewrite_meta_opcode_counter (opcode_counter_t meta_oc,
+                             opcode_counter_t new_value)
+{
+  JERRY_STATIC_ASSERT (sizeof (idx_t) == 1);
+
+  const idx_t data_1 = (idx_t) (new_value >> JERRY_BITSINBYTE);
+  const idx_t data_2 = (idx_t) (new_value & ((1 << JERRY_BITSINBYTE) - 1));
+
+  JERRY_ASSERT (new_value == calc_meta_opcode_counter_from_meta_data (data_1, data_2));
+
+  REWRITE_OPCODE_3 (meta_oc, meta, OPCODE_META_TYPE_OPCODE_COUNTER, data_1, data_2);
+}
+
 /* function_declaration
   : 'function' LT!* Identifier LT!*
     '(' (LT!* Identifier (LT!* ',' LT!* Identifier)*) ? LT!* ')' LT!* function_body
@@ -905,7 +919,7 @@ static void
 parse_function_declaration (void)
 {
   idx_t name;
-  opcode_counter_t jmp_oc;
+  opcode_counter_t meta_oc;
 
   assert_keyword (KW_FUNCTION);
 
@@ -916,8 +930,8 @@ parse_function_declaration (void)
   skip_newlines ();
   parse_argument_list (AL_FUNC_DECL, name);
 
-  jmp_oc = opcode_counter;
+  meta_oc = opcode_counter;
-  DUMP_OPCODE_1 (jmp_down, INVALID_VALUE);
+  DUMP_OPCODE_3 (meta, OPCODE_META_TYPE_OPCODE_COUNTER, INVALID_VALUE, INVALID_VALUE);
 
   token_after_newlines_must_be (TOK_OPEN_BRACE);
 
@@ -929,7 +943,8 @@ parse_function_declaration (void)
   next_token_must_be (TOK_CLOSE_BRACE);
 
   DUMP_VOID_OPCODE (ret);
-  REWRITE_OPCODE_1 (jmp_oc, jmp_down, opcode_counter - jmp_oc);
+
+  rewrite_meta_opcode_counter (meta_oc, opcode_counter);
 }
 
 /* function_expression
@@ -939,7 +954,7 @@ static idx_t
 parse_function_expression (void)
 {
   idx_t name, lhs;
-  opcode_counter_t jmp_oc;
+  opcode_counter_t meta_oc;
 
   assert_keyword (KW_FUNCTION);
 
@@ -957,8 +972,8 @@ parse_function_expression (void)
   skip_newlines ();
   lhs = parse_argument_list (AL_FUNC_EXPR, name);
 
-  jmp_oc = opcode_counter;
+  meta_oc = opcode_counter;
-  DUMP_OPCODE_1 (jmp_down, INVALID_VALUE);
+  DUMP_OPCODE_3 (meta, OPCODE_META_TYPE_OPCODE_COUNTER, INVALID_VALUE, INVALID_VALUE);
 
   token_after_newlines_must_be (TOK_OPEN_BRACE);
 
@@ -970,7 +985,7 @@ parse_function_expression (void)
   token_after_newlines_must_be (TOK_CLOSE_BRACE);
 
   DUMP_VOID_OPCODE (ret);
-  REWRITE_OPCODE_1 (jmp_oc, jmp_down, opcode_counter - jmp_oc);
+  rewrite_meta_opcode_counter (meta_oc, opcode_counter);
 
   return lhs;
 }

tests/jerry/function_args.js

@@ -30,16 +30,17 @@ function f1(x)
   assert(t === false);
 }
 
+var i;
 var t = true;
 
-for(var i = 1; i <= 10; i++)
+for(i = 1; i <= 10; i++)
 {
   f1(i);
 }
 
 t = false;
 
-for(var i = 11; i <= 20; i++)
+for(i = 11; i <= 20; i++)
 {
   f1(i);
 }

tests/jerry/nested_function.js

@@ -12,14 +12,8 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-var k;
-
 function f1()
 {
-  k = 17;
-
-  f2();
-
   function f2()
     {
       assert(k > 0);
@@ -32,9 +26,16 @@ function f1()
 
       f2();
     }
+
+  k = 17;
+
+  f2();
 }
 
-for(var i = 0; i < 10000; i++)
+var k;
+var i;
+
+for(i = 0; i < 10000; i++)
 {
   f1();
 }