1# Compilation and Building \(for Mini and Small Systems\)<a name="EN-US_TOPIC_0000001130006475"></a> 2 3- [Introduction](#section11660541593) 4- [Directory Structure](#section161941989596) 5- [Usage](#section1312121216216) 6 - [Usage Guidelines](#section129654513264) 7 8- [Repositories Involved](#section1371113476307) 9 10## Introduction<a name="section11660541593"></a> 11 12The compilation and building subsystem is a build framework based on Generate Ninja \(GN\) and Ninja, which supports component-based OpenHarmony development. This subsystem can be used to: 13 14- Build products. 15 16- Build chipset vendor components independently. 17- Build a single component independently. 18 19It is considered best practice to learn the following basic concepts before you start development and build: 20 21- **Component** 22 23 A component is a reusable software unit that can contain source code, configuration files, resource files, and build scripts. 24 25- **GN** 26 27 GN is short for Generate Ninja, which is a build system used to generate Ninja files. 28 29- **Ninja** 30 31 Ninja is a small high-speed build system. 32 33 34**Build Process** 35 36The following figure shows the build process. 37 38**Figure 1** Build process<a name="fig1531311552204"></a> 39 40 411. **hb set**: Set the OpenHarmony source code directory and the product to build. 422. **hb build**: Build the product, development board, or component. The process to build the solution is as follows: 43 - **Reading configuration**: Read the development board configuration, which covers the toolchain, linking commands, and build options. 44 - **Running gn**: Run the **gn gen** command to read the product configuration \(related to the development board, kernel, and system components\) and generate the **out** directory and **ninja** files for the solution. 45 - **Running Ninja**: Run **ninja -C out/company/product** to start build. 46 - **Packaging**: Package the build result to create a file system image. 47 48 49## Directory Structure<a name="section161941989596"></a> 50 51``` 52build/lite # Primary directory 53├── components # Component description file 54├── hb # hb pip installation package 55├── make_rootfs # make script for the file system 56├── config # Build configuration items 57│ ├── component # Definitions of component-related templates, including static libraries, dynamic libraries, extension components, and emulator libraries 58│ ├── kernel # Build configuration parameters of the kernel 59│ └── subsystem # Subsystem template 60├── ndk # NDK-related build scripts and configuration parameters 61└── toolchain # Build toolchain, which contain the compiler directories, build options, and linking options 62``` 63 64## Usage<a name="section1312121216216"></a> 65 66### Usage Guidelines<a name="section129654513264"></a> 67 681. **Prerequisites** 69 - Server and OS version: Linux server running 64-bit Ubuntu 16.04 or later 70 - Python version: 3.7.4 or later 71 - Repository: **build\_lite** of OpenHarmony source code 72 732. **Installing hb** 74 - Run the following command in the root directory of the source code: 75 76 ``` 77 python3 -m pip install --user build/lite 78 ``` 79 80 - Run the **hb -h** command. If the following information is displayed, the installation is successful: 81 82 ``` 83 usage: hb 84 85 OHOS build system 86 87 positional arguments: 88 {build,set,env,clean} 89 build Build source code 90 set OHOS build settings 91 env Show OHOS build env 92 clean Clean output 93 94 optional arguments: 95 -h, --help Show this help message and exit 96 ``` 97 98 - **Uninstalling hb** 99 100 Run the following command to uninstall hb: 101 102 ``` 103 python3 -m pip uninstall ohos-build 104 ``` 105 106 1073. **Build Commands** 108 1. **hb set** 109 110 ``` 111 hb set -h 112 usage: hb set [-h] [-root [ROOT_PATH]] [-p] 113 114 optional arguments: 115 -h, --help Show this help message and exit. 116 -root [ROOT_PATH], --root_path [ROOT_PATH] 117 Set OHOS root path. 118 -p, --product Set OHOS board and kernel. 119 ``` 120 121 - If you run **hb set** with no argument, the default setting process starts. 122 - You can run **hb set -root** _\[ROOT\_PATH\]_ to set the root directory of the source code. 123 - **hb set -p --product** is used to set the product to build. 124 125 2. **hb env** 126 127 View the current configuration. 128 129 ``` 130 hb env 131 [OHOS INFO] root path: xxx 132 [OHOS INFO] board: hispark_taurus 133 [OHOS INFO] kernel: liteos 134 [OHOS INFO] product: ipcamera 135 [OHOS INFO] product path: xxx/vendor/hisilicon/ipcamera 136 [OHOS INFO] device path: xxx/device/hisilicon/hispark_taurus/sdk_linux_4.19 137 ``` 138 139 3. **hb build** 140 141 ``` 142 hb build -h 143 usage: hb build [-h] [-b BUILD_TYPE] [-c COMPILER] [-t [TEST [TEST ...]]] 144 [--dmverity] [-p PRODUCT] [-f] [-n] 145 [component [component ...]] 146 147 positional arguments: 148 component Name of the component. 149 150 optional arguments: 151 -h, --help Show this help message and exit. 152 -b BUILD_TYPE, --build_type BUILD_TYPE 153 Release or debug version. 154 -c COMPILER, --compiler COMPILER 155 Specify compiler. 156 -t [TEST [TEST ...]], --test [TEST [TEST ...]] 157 Compile test suit. 158 --dmverity Enable dmverity. 159 -p PRODUCT, --product PRODUCT 160 Build a specified product with 161 {product_name}@{company}, eg: ipcamera@hisilcon. 162 -f, --full Full code compilation. 163 -T [TARGET [TARGET ...]], --target [TARGET [TARGET ...]] 164 Compile single target 165 ``` 166 167 - If you run **hb build** with no argument, the previously configured code directory, product, and options are used for build. 168 - You can run **hb build** _\{component\}_ to build product components separately based on the development board and kernel set for the product, for example, **hb build kv\_store**. 169 - You can run **hb build -p PRODUCT** to skip the setting step and build the product directly. 170 - You can run **hb build** in **device/device\_company/board** to select the kernel and start build based on the current development board and the selected kernel to generate an image that contains the kernel and driver only. 171 172 4. **hb clean** 173 174 Clear the build result of the product in the **out** directory, and leave the **args.gn** and **build.log** files only. To clear files in a specified directory, add the directory parameter to the command, for example, **hb clean** _xxx_**/out/**_xxx_. 175 176 ``` 177 hb clean 178 usage: hb clean [-h] [out_path] 179 180 positional arguments: 181 out_path Clean a specified path. 182 183 optional arguments: 184 -h, --help Show this help message and exit. 185 ``` 186 187 188 189## Repositories Involved<a name="section1371113476307"></a> 190 191Compilation and building subsystem 192 193**[build\_lite](https://gitee.com/openharmony/build_lite)**
