!631 add ark runtime subsystem

Merge pull request !631 from Han/my

en/readme/ARK-Runtime-Subsystem.md

+# ARK Runtime Subsystem<a name="EN-US_TOPIC_0000001138852894"></a>
+
+- [ARK Runtime Subsystem<a name="EN-US_TOPIC_0000001138852894"></a>](#ark-runtime-subsystem)
+  - [Introduction<a name="section11660541593"></a>](#introduction)
+  - [Directory Structure<a name="section161941989596"></a>](#directory-structure)
+  - [Usage Guide<a name="section18393638195820"></a>](#usage-guide)
+  - [Repositories Involved<a name="section1371113476307"></a>](#repositories-involved)
+
+## Introduction<a name="section11660541593"></a>
+
+ARK is a unified programming platform developed by Huawei. Its key components include a compiler, toolchain, and runtime. ARK supports compilation and execution of high-level programming languages on the multiple hardware platform and accelerates the execution of the OpenHarmony operating system and its applications and services on mobile phones, PCs, tablets, TVs, automobiles, and smart wearables. The ARK-JS open sourced this time provides the capability of compiling and running the JavaScript \(JS\) language on the standard system of OpenHarmony.
+
+The ARK-JS consists of two parts: JS compiler toolchain and JS runtime. The JS compiler toolchain compiles JS source code into ARK bytecodes. The JS runtime executes the generated ARK bytecodes. Unless otherwise specified, bytecodes refer to ARK bytecodes in this document.
+
+The following figure shows the architecture of the JS compiler toolchain.
+
+![](figures/en-us_image_ark_frontend.png)
+
+The JS front-end compiler parses the JS source code into an abstract syntax tree \(AST\), which is processed by the AST transformer, bytecode generator, and register allocator. The native emiter generates the ARK bytecode file \(.abc\).
+
+The following figure shows the JS runtime architecture.
+
+![](figures/en-us_image_ark_runtime.png)
+
+ARK-JS Runtime runs ARK bytecode files to implement JS semantic logic.
+
+ARK-JS Runtime consists of the following:
+
+-   Core Runtime
+
+    Core Runtime consists of basic language-irrelevant runtime libraries, including ARK File, Tooling, and ARK Base. ARK File provides bytecodes. Tooling supports Debugger. ARK Base is responsible for implementing system calls.
+
+-   Execution Engine
+
+    The Execution Engine consists of an interpreter that executes bytecodes, Inline Caches that store hidden classes, and Profiler that analyzes and records runtime types.
+
+-   ECMAScript Runtime
+
+    ECMAScript Runtime consists of the JS object allocator, garbage collector \(GC\), and an internal library that supports ECMAScript specifications.
+
+-   ARK Foreign Function Interface \(AFFI\)
+
+    The AFFI provides a C++ function interface for ARK-JS runtime.
+
+
+## Directory Structure<a name="section161941989596"></a>
+
+```
+/ark
+├── js_runtime       # JS runtime module
+├── runtime_core     # Runtime common module
+└── ts2abc           # JS front-end tool
+```
+
+## Usage Guide<a name="section18393638195820"></a>
+
+[ARK-Runtime-Usage-Guide](https://gitee.com/openharmony/ark_js_runtime/blob/master/docs/ARK-Runtime-Usage-Guide.md)
+
+## Repositories Involved<a name="section1371113476307"></a>
+
+[ark\_runtime\_core](https://gitee.com/openharmony/ark_runtime_core)
+
+[ark\_js\_runtime](https://gitee.com/openharmony/ark_js_runtime)
+
+[ark\_ts2abc](https://gitee.com/openharmony/ark_ts2abc)

zh-cn/readme/ARK-Runtime-Subsystem-zh.md

+# 方舟运行时子系统<a name="ZH-CN_TOPIC_0000001138852894"></a>
+
+- [方舟运行时子系统<a name="ZH-CN_TOPIC_0000001138852894"></a>](#方舟运行时子系统)
+  - [简介<a name="section11660541593"></a>](#简介)
+  - [目录<a name="section161941989596"></a>](#目录)
+  - [使用指南<a name="section18393638195820"></a>](#使用指南)
+  - [相关仓<a name="section1371113476307"></a>](#相关仓)
+
+## 简介<a name="section11660541593"></a>
+
+方舟\(ARK\)是华为自研的统一编程平台，包含编译器、工具链、运行时等关键部件，支持高级语言在多种芯片平台的编译与运行，并支撑OpenHarmony操作系统及其应用和服务运行在手机、个人电脑、平板、电视、汽车和智能穿戴等多种设备上的需求。本次开源的ARK-JS提供的能力是在OpenHarmony标准系统\(standard system\)中编译和运行JavaScript语言\(本文后面简称JS\)。
+
+本次开源的ARK-JS分成两个部分，分别是JS编译工具链与JS运行时。JS工具链将JS源码编译成方舟字节码\(ARK Bytecode\)，JS运行时负责执行生成的方舟字节码\(后续如无特殊说明，字节码特指方舟字节码\)。
+
+JS编译工具链架构：
+
+![](figures/zh-cn_image_ark_frontend.png)
+
+JS前端编译器，将JavaScript源码解析为AST\( Abstract Syntax Tree\)后，经过AST变换、字节码生成器、寄存器分配后由native emiter产生方舟字节码文件\(abc文件\)
+
+JS运行时（Runtime）架构：
+
+![](figures/zh-cn_image_ark_runtime.png)
+
+ARK-JS Runtime以方舟字节码文件作为输入并直接运行字节码文件，实现对应的JS语义逻辑。
+
+ARK-JS Runtime主要由四个部分组成：
+
+-   Core Runtime
+
+    Core Runtime主要由语言无关的基础运行库组成，包括承载字节码的ARK File组件、支持Debugger的Tooling组件、负责对应系统调用的ARK Base组件等。
+
+-   Execution Engine
+
+    执行引擎目前包含执行字节码的解释器、缓存隐藏类和内联缓存、以及剖析记录运行时类型的Profiler。
+
+-   ECMAScript Runtime
+
+    ECMAScript Runtime则包含了各种JS对象的分配器、垃圾回收器、以及用以支撑ECMAScript规范的内部运行库。
+
+-   AFFI \(ARK Foreign Function Interface\)
+
+    AFFI是ARK JS运行时的C++语言外部函数接口。
+
+
+## 目录<a name="section161941989596"></a>
+
+```
+/ark
+├── js_runtime       # JS运行时组件
+├── runtime_core     # 运行时公共组件
+└── ts2abc           # JS语言的前端工具
+```
+
+## 使用指南<a name="section18393638195820"></a>
+
+[方舟运行时使用指南](https://gitee.com/openharmony/ark_js_runtime/blob/master/docs/ARK-Runtime-Usage-Guide-zh.md)
+
+## 相关仓<a name="section1371113476307"></a>
+
+[ark\_runtime\_core](https://gitee.com/openharmony/ark_runtime_core)
+
+[ark\_js\_runtime](https://gitee.com/openharmony/ark_js_runtime)
+
+[ark\_ts2abc](https://gitee.com/openharmony/ark_ts2abc)