Rework RegExp engine and add support for proper unicode matching (#3746)

This change includes several bugfixes, general improvements, and support
for additional features.
- Added full support for web compatibility syntax defined in Annex B
- Implemented parsing and matching patterns in unicode mode
- Fixed capture results when iterating with nested capturing groups
- Significantly reduced regexp bytecode size
- Reduced stack usage during regexp execution
- Improved matching performance

JerryScript-DCO-1.0-Signed-off-by: Dániel Bátyai dbatyai@inf.u-szeged.hu

jerry-core/parser/js/js-lexer.c

@@ -2847,9 +2847,6 @@ lexer_construct_regexp_object (parser_context_t *context_p, /**< context */
   context_p->literal_count++;
 
   /* Compile the RegExp literal and store the RegExp bytecode pointer */
-  const re_compiled_code_t *re_bytecode_p = NULL;
-  ecma_value_t completion_value;
-
   ecma_string_t *pattern_str_p = NULL;
 
   if (lit_is_valid_cesu8_string (regex_start_p, length))
@@ -2862,19 +2859,14 @@ lexer_construct_regexp_object (parser_context_t *context_p, /**< context */
     pattern_str_p = ecma_new_ecma_string_from_utf8_converted_to_cesu8 (regex_start_p, length);
   }
 
-  completion_value = re_compile_bytecode (&re_bytecode_p,
-                                          pattern_str_p,
-                                          current_flags);
+  re_compiled_code_t *re_bytecode_p = re_compile_bytecode (pattern_str_p, current_flags);
   ecma_deref_ecma_string (pattern_str_p);
 
-  if (ECMA_IS_VALUE_ERROR (completion_value))
+  if (JERRY_UNLIKELY (re_bytecode_p == NULL))
   {
-    jcontext_release_exception ();
     parser_raise_error (context_p, PARSER_ERR_INVALID_REGEXP);
   }
 
-  ecma_free_value (completion_value);
-
   literal_p->type = LEXER_REGEXP_LITERAL;
   literal_p->u.bytecode_p = (ecma_compiled_code_t *) re_bytecode_p;
 

jerry-core/parser/js/js-parser.c

@@ -2723,6 +2723,14 @@ parser_parse_script (const uint8_t *arg_list_p, /**< function argument list */
       jcontext_raise_exception (ECMA_VALUE_NULL);
       return ECMA_VALUE_ERROR;
     }
+
+    if (parser_error.error == PARSER_ERR_INVALID_REGEXP)
+    {
+      /* The RegExp compiler has already raised an exception. */
+      JERRY_ASSERT (jcontext_has_pending_exception ());
+      return ECMA_VALUE_ERROR;
+    }
+
 #if ENABLED (JERRY_ERROR_MESSAGES)
     const lit_utf8_byte_t *err_bytes_p = (const lit_utf8_byte_t *) parser_error_to_string (parser_error.error);
     lit_utf8_size_t err_bytes_size = lit_zt_utf8_string_size (err_bytes_p);