Fix parse of simple for statement.

Related issue: #156

JerryScript-DCO-1.0-Signed-off-by: Ruben Ayrapetyan r.ayrapetyan@samsung.com

Author: Ruben Ayrapetyan

jerry-core/parser/js/parser.cpp

@@ -220,6 +220,67 @@ jsp_skip_braces (token_type brace_type) /**< type of the opening brace */
   current_token_must_be (closing_bracket_type);
 } /* jsp_skip_braces */
 
+/**
+ * Find next token of specified type before the specified location
+ *
+ * Note:
+ *      If skip_brace_blocks is true, every { should correspond to } brace before search end location,
+ *      otherwise a syntax error is raised.
+ *
+ * @return true - if token was found (in the case, it is the current token,
+ *                                    and lexer locus points to it),
+ *         false - otherwise (in the case, lexer locus points to end_loc).
+ */
+static bool
+jsp_find_next_token_before_the_locus (token_type token_to_find, /**< token to search for
+                                                                 *   (except TOK_NEWLINE and TOK_EOF) */
+                                      locus end_loc, /**< location to search before */
+                                      bool skip_brace_blocks) /**< skip blocks, surrounded with { and } braces */
+{
+  JERRY_ASSERT (token_to_find != TOK_NEWLINE
+                && token_to_find != TOK_EOF);
+
+  while (tok.loc < end_loc)
+  {
+    if (skip_brace_blocks)
+    {
+      if (token_is (TOK_OPEN_BRACE))
+      {
+        jsp_skip_braces (TOK_OPEN_BRACE);
+
+        JERRY_ASSERT (token_is (TOK_CLOSE_BRACE));
+        skip_newlines ();
+
+        if (tok.loc >= end_loc)
+        {
+          lexer_seek (end_loc);
+          tok = lexer_next_token ();
+
+          return false;
+        }
+      }
+      else if (token_is (TOK_CLOSE_BRACE))
+      {
+        EMIT_ERROR ("Unmatched } brace");
+      }
+    }
+
+    if (token_is (token_to_find))
+    {
+      return true;
+    }
+    else
+    {
+      JERRY_ASSERT (!token_is (TOK_EOF));
+    }
+
+    skip_newlines ();
+  }
+
+  JERRY_ASSERT (tok.loc == end_loc);
+  return false;
+} /* jsp_find_next_token_before_the_locus */
+
 /* property_name
   : Identifier
   | Keyword
@@ -1726,88 +1787,146 @@ parse_variable_declaration (void)
     (LT!* ',' LT!* variable_declaration)*
   ; */
 static void
-parse_variable_declaration_list (bool *several_decls)
+parse_variable_declaration_list (void)
 {
+  JERRY_ASSERT (is_keyword (KW_VAR));
+
   while (true)
   {
+    skip_newlines ();
+
     parse_variable_declaration ();
 
     skip_newlines ();
     if (!token_is (TOK_COMMA))
     {
       lexer_save_token (tok);
-      return;
-    }
-
-    skip_newlines ();
-    if (several_decls)
-    {
-      *several_decls = true;
+      break;
     }
   }
 }
 
+/**
+ * Parse for statement
+ *
+ * See also:
+ *          ECMA-262 v5, 12.6.3
+ *
+ * Note:
+ *      Syntax:
+ *               Initializer                      Condition     Increment     Body      LoopEnd
+ *       - for ([ExpressionNoIn];                [Expression]; [Expression]) Statement
+ *       - for (var VariableDeclarationListNoIn; [Expression]; [Expression]) Statement
+ *
+ * Note:
+ *      Layout of generated byte-code is the following:
+ *                        Initializer ([ExpressionNoIn] / VariableDeclarationListNoIn)
+ *                        Jump -> ConditionCheck
+ *        NextIteration:
+ *                        Body (Statement)
+ *        ContinueTarget:
+ *                        Increment ([Expression])
+ *        ConditionCheck:
+ *                        Condition ([Expression])
+ *                        If Condition is evaluted to true, jump -> NextIteration
+ */
 static void
-parse_plain_for (jsp_label_t *outermost_stmt_label_p) /**< outermost (first) label, corresponding to
-                                                       *   the statement (or NULL, if there are no named
-                                                       *   labels associated with the statement) */
+jsp_parse_for_statement (jsp_label_t *outermost_stmt_label_p, /**< outermost (first) label, corresponding to
+                                                               *   the statement (or NULL, if there are no named
+                                                               *   labels associated with the statement) */
+                         locus for_body_statement_loc) /**< locus of loop body statement */
 {
-  dump_jump_to_end_for_rewrite ();
-
-  // Skip till body
-  JERRY_ASSERT (token_is (TOK_SEMICOLON));
+  current_token_must_be (TOK_OPEN_PAREN);
   skip_newlines ();
-  const locus cond_loc = tok.loc;
-  while (!token_is (TOK_SEMICOLON))
+
+  // Initializer
+  if (is_keyword (KW_VAR))
   {
-    skip_newlines ();
+    parse_variable_declaration_list ();
+    skip_token ();
   }
-  skip_newlines ();
-  const locus incr_loc = tok.loc;
-  while (!token_is (TOK_CLOSE_PAREN))
+  else if (!token_is (TOK_SEMICOLON))
   {
-    skip_newlines ();
+    parse_expression (false, JSP_EVAL_RET_STORE_NOT_DUMP);
+    skip_token ();
   }
+  else
+  {
+    // Initializer is empty
+  }
+
+  // Jump -> ConditionCheck
+  dump_jump_to_end_for_rewrite ();
 
   dumper_set_next_interation_target ();
 
-  // Parse body
+  current_token_must_be (TOK_SEMICOLON);
+  skip_token ();
+
+  // Save Condition locus
+  const locus condition_loc = tok.loc;
+
+  if (!jsp_find_next_token_before_the_locus (TOK_SEMICOLON,
+                                             for_body_statement_loc,
+                                             true))
+  {
+    EMIT_ERROR ("Invalid for statement");
+  }
+
+  current_token_must_be (TOK_SEMICOLON);
+  skip_token ();
+
+  // Save Increment locus
+  const locus increment_loc = tok.loc;
+
+  // Body
+  lexer_seek (for_body_statement_loc);
   skip_newlines ();
+
   parse_statement (NULL);
 
-  const locus end_loc = tok.loc;
+  // Save LoopEnd locus
+  const locus loop_end_loc = tok.loc;
 
+  // Setup ContinueTarget
   jsp_label_setup_continue_target (outermost_stmt_label_p,
                                    serializer_get_current_opcode_counter ());
 
-  lexer_seek (incr_loc);
-  skip_token ();
+  // Increment
+  lexer_seek (increment_loc);
+  skip_newlines ();
+
   if (!token_is (TOK_CLOSE_PAREN))
   {
     parse_expression (true, JSP_EVAL_RET_STORE_NOT_DUMP);
   }
 
+  current_token_must_be (TOK_CLOSE_PAREN);
+
+  // Setup ConditionCheck
   rewrite_jump_to_end ();
 
-  lexer_seek (cond_loc);
-  skip_token ();
+  // Condition
+  lexer_seek (condition_loc);
+  skip_newlines ();
+
   if (token_is (TOK_SEMICOLON))
   {
     dump_continue_iterations_check (empty_operand ());
   }
   else
   {
-    const operand cond = parse_expression (true, JSP_EVAL_RET_STORE_NOT_DUMP);
+    operand cond = parse_expression (true, JSP_EVAL_RET_STORE_NOT_DUMP);
     dump_continue_iterations_check (cond);
   }
 
-  lexer_seek (end_loc);
-  skip_token ();
+  lexer_seek (loop_end_loc);
+  skip_newlines ();
   if (tok.type != TOK_CLOSE_BRACE)
   {
     lexer_save_token (tok);
   }
-}
+} /* jsp_parse_for_statement */
 
 static void
 parse_for_in (jsp_label_t *outermost_stmt_label_p) /**< outermost (first) label, corresponding to
@@ -1819,92 +1938,48 @@ parse_for_in (jsp_label_t *outermost_stmt_label_p) /**< outermost (first) label,
   EMIT_SORRY ("'for in' loops are not supported yet");
 }
 
-/* for_statement
-  : 'for' LT!* '(' (LT!* for_statement_initialiser_part)? LT!* ';'
-    (LT!* expression)? LT!* ';' (LT!* expression)? LT!* ')' LT!* statement
-  ;
-
-   for_statement_initialiser_part
-  : expression
-  | 'var' LT!* variable_declaration_list
-  ;
-
-   for_in_statement
-  : 'for' LT!* '(' LT!* for_in_statement_initialiser_part LT!* 'in'
-    LT!* expression LT!* ')' LT!* statement
-  ;
-
-   for_in_statement_initialiser_part
-  : left_hand_side_expression
-  | 'var' LT!* variable_declaration
-  ;*/
-
+/**
+ * Parse for/for-in statements
+ *
+ * See also:
+ *          ECMA-262 v5, 12.6.3 and 12.6.4
+ */
 static void
-parse_for_or_for_in_statement (jsp_label_t *outermost_stmt_label_p) /**< outermost (first) label, corresponding to
-                                                                     *   the statement (or NULL, if there are no named
-                                                                     *   labels associated with the statement) */
+jsp_parse_for_or_for_in_statement (jsp_label_t *outermost_stmt_label_p) /**< outermost (first) label,
+                                                                         *   corresponding to the statement
+                                                                         *   (or NULL, if there are no name
+                                                                         *   labels associated with the statement) */
 {
   assert_keyword (KW_FOR);
   token_after_newlines_must_be (TOK_OPEN_PAREN);
 
-  skip_newlines ();
-  if (token_is (TOK_SEMICOLON))
-  {
-    parse_plain_for (outermost_stmt_label_p);
-    return;
-  }
-  /* Both for_statement_initialiser_part and for_in_statement_initialiser_part
-     contains 'var'. Check it first.  */
-  if (is_keyword (KW_VAR))
-  {
-    bool several_decls = false;
-    skip_newlines ();
-    parse_variable_declaration_list (&several_decls);
-    if (several_decls)
-    {
-      token_after_newlines_must_be (TOK_SEMICOLON);
-      parse_plain_for (outermost_stmt_label_p);
-      return;
-    }
-    else
-    {
-      skip_newlines ();
-      if (token_is (TOK_SEMICOLON))
-      {
-        parse_plain_for (outermost_stmt_label_p);
-        return;
-      }
-      else if (is_keyword (KW_IN))
-      {
-        parse_for_in (outermost_stmt_label_p);
-        return;
-      }
-      else
-      {
-        EMIT_ERROR ("Expected either ';' or 'in' token");
-      }
-    }
-  }
+  locus for_open_paren_loc, for_body_statement_loc;
 
-  /* expression contains left_hand_side_expression.  */
-  parse_expression (false, JSP_EVAL_RET_STORE_NOT_DUMP);
+  for_open_paren_loc = tok.loc;
 
+  jsp_skip_braces (TOK_OPEN_PAREN);
   skip_newlines ();
-  if (token_is (TOK_SEMICOLON))
-  {
-    parse_plain_for (outermost_stmt_label_p);
-    return;
-  }
-  else if (is_keyword (KW_IN))
+
+  for_body_statement_loc = tok.loc;
+
+  lexer_seek (for_open_paren_loc);
+  tok = lexer_next_token ();
+
+  bool is_plain_for = jsp_find_next_token_before_the_locus (TOK_SEMICOLON,
+                                                            for_body_statement_loc,
+                                                            true);
+  lexer_seek (for_open_paren_loc);
+  tok = lexer_next_token ();
+
+  if (is_plain_for)
   {
-    parse_for_in (outermost_stmt_label_p);
-    return;
+    jsp_parse_for_statement (outermost_stmt_label_p, for_body_statement_loc);
   }
   else
   {
-    EMIT_ERROR ("Expected either ';' or 'in' token");
+    parse_for_in (outermost_stmt_label_p);
   }
-}
+} /* jsp_parse_for_or_for_in_statement */
 
 static operand
 parse_expression_inside_parens (void)
@@ -2318,7 +2393,7 @@ parse_iterational_statement (jsp_label_t *outermost_named_stmt_label_p) /**< out
   else
   {
     JERRY_ASSERT (is_keyword (KW_FOR));
-    parse_for_or_for_in_statement (outermost_stmt_label_p);
+    jsp_parse_for_or_for_in_statement (outermost_stmt_label_p);
   }
 
   jsp_label_rewrite_jumps_and_pop (&label,
@@ -2412,8 +2487,7 @@ parse_statement (jsp_label_t *outermost_stmt_label_p) /**< outermost (first) lab
   }
   if (is_keyword (KW_VAR))
   {
-    skip_newlines ();
-    parse_variable_declaration_list (NULL);
+    parse_variable_declaration_list ();
     return;
   }
   if (is_keyword (KW_FUNCTION))