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/regexp/re-compiler-context.h

@@ -0,0 +1,60 @@
+/* Copyright JS Foundation and other contributors, http://js.foundation
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef RE_COMPILER_CONTEXT_H
+#define RE_COMPILER_CONTEXT_H
+
+#if ENABLED (JERRY_BUILTIN_REGEXP)
+
+#include "re-token.h"
+
+/** \addtogroup parser Parser
+ * @{
+ *
+ * \addtogroup regexparser Regular expression
+ * @{
+ *
+ * \addtogroup regexparser_compiler Compiler
+ * @{
+ */
+
+/**
+ * RegExp compiler context
+ */
+typedef struct
+{
+  const lit_utf8_byte_t *input_start_p; /**< start of input pattern */
+  const lit_utf8_byte_t *input_curr_p;  /**< current position in input pattern */
+  const lit_utf8_byte_t *input_end_p;   /**< end of input pattern */
+
+  uint8_t *bytecode_start_p;            /**< start of bytecode block */
+  size_t bytecode_size;                 /**< size of bytecode */
+
+  uint32_t captures_count;              /**< number of capture groups */
+  uint32_t non_captures_count;          /**< number of non-capture groups */
+
+  int groups_count;                     /**< number of groups */
+  uint16_t flags;                       /**< RegExp flags */
+  re_token_t token;                     /**< current token */
+} re_compiler_ctx_t;
+
+/**
+ * @}
+ * @}
+ * @}
+ */
+
+#endif /* ENABLED (JERRY_BUILTIN_REGEXP) */
+#endif /* !RE_COMPILER_CONTEXT_H */