xPack C/C++ Managed Build (beta)

A VS Code extension to manage and build C/C++ projects with CMake, meson, etc, using the xPack tools.

It is intended as a replacement for the managed build system available in Eclipse Embedded CDT.

Features

Manage typical multi-configuration projects (like Debug/Release), but also complex, multi-platform, multi-architecture, multi-toolchain projects, with an emphasis on modern C/C++ and embedded applications.

Overview

The xPack C/C++ Managed Build extension is an open source project hosted on GitHub and is part of the xPack Reproducible Build Framework.

It can be installed from the VisualStudio Marketplace as ilg-vscode.xpack and it pulls its own dependencies (like the C/C++).

Prerequisites (node/npm)

VS Code 1.54 or later and a recent xpm, which is a portable Node.js command line application, available from npmjs.com.

npm install --global xpm@latest

For details please follow the instructions in the install page.

Quick Start

TL;DR: View → Command Palette... → xPack: Quick Start a Hello World project (C++, CMake) (but better read the Quick Start page).

The simplest way to start with the VS Code xPack C/C++ Managed Build extension is to create a simple Hello World project.

Open the Quick Start page in a browser and follow the steps. In addition to being a fully functional project, the result can also be a good starting point for more complex projects.

How it works

The xPack Reproducible Build Framework is not necessarily specific to VS Code, it is a set of portable CLI tools, neutral to any build system, which can basically invoke any 3rd party tools, old and new, to perform the actual build; it favours modern tools (like CMake and meson) which can generate a compile_commands.json file, since this greatly simplifies integration with indexers (like VS Code IntelliSense), but with some care can also be used with legacy tools like autotools and make.

Future versions of the xPack Reproducible Build Framework are planned to include an integrated build system generator, similar to that used in Eclipse CDT.

Disclaimer

The xPack project does not introduce a new package format, but inherits from the simplicity of npm; it adds a few more definitions to package.json, but otherwise it uses exactly the same project format as npm; xPacks are actually npm packages, and can be stored in usual Git repositories, or even published on npmjs.com or compatible servers.

Concepts (configurations & actions)

Compared to typical CMake/meson projects, which in most cases use a single build folder, an xPack Managed Build project is by design defined as

a collection of named build configurations

each using a separate build folder, and

each with its own set of named actions

defined as sequences of commands (stored in JSON as arrays of string).

xPack Actions

To avoid redundant definitions between configurations, the actions can use generic templates, with substitutions performed by the LiquidJS template engine, based on user defined string properties.

A typical example of a project with two build configurations, using CMake, may look like:

{
  "name": "hello-world",
  "version": "0.1.0",
  "description": "A Hello World project",
  "main": "",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "keywords": [
    "xpack"
  ],
  "license": "MIT",
  "config": {},
  "dependencies": {},
  "devDependencies": {
    "@xpack-dev-tools/cmake": "3.19.2-2.1",
    "@xpack-dev-tools/gcc": "8.5.0-1.1",
    "@xpack-dev-tools/ninja-build": "1.10.2-2.1"
  },
  "xpack": {
    "minimumXpmRequired": "0.10.1",
    "properties": {
      "buildFolderRelativePath": "build{{ path.sep }}{{ configuration.name | downcase }}",
      "toolchainFileName": "toolchain-gcc.cmake",
      "commandPrepare": "cmake -S . -B {{ properties.buildFolderRelativePath }} -G Ninja -D CMAKE_BUILD_TYPE={{ properties.buildType }} -D CMAKE_EXPORT_COMPILE_COMMANDS=ON",
      "commandPrepareWithToolchain": "{{ properties.commandPrepare }} -D CMAKE_TOOLCHAIN_FILE={{ properties.toolchainFileName }}",
      "commandReconfigure": "{{ properties.commandPrepare }}",
      "commandBuild": "cmake --build {{ properties.buildFolderRelativePath }}",
      "commandClean": "cmake --build {{ properties.buildFolderRelativePath }} --target clean",
      "commandExecuteHello": "{{ properties.buildFolderRelativePath }}{{ path.sep }}hello-world"
    },
    "actions": {
      "prepare-all": [
        "xpm run prepare --config Debug",
        "xpm run prepare --config Release"
      ],
      "build-all": [
        "xpm run build --config Debug",
        "xpm run build --config Release"
      ],
      "clean-all": [
        "xpm run clean --config Debug",
        "xpm run clean --config Release"
      ],
      "execute-all": [
        "xpm run execute --config Debug",
        "xpm run execute --config Release"
      ],
      "test": [
        "xpm run build-all",
        "xpm run execute-all"
      ]
    },
    "buildConfigurations": {
      "Debug": {
        "properties": {
          "buildType": "Debug"
        },
        "actions": {
          "prepare": "{{ properties.commandPrepareWithToolchain }}",
          "build": [
            "{{ properties.commandReconfigure }}",
            "{{ properties.commandBuild }}"
          ],
          "clean": "{{ properties.commandClean }}",
          "execute": "{{ properties.commandExecuteHello }}"
        }
      },
      "Release": {
        "properties": {
          "buildType": "Release"
        },
        "actions": {
          "prepare": "{{ properties.commandPrepareWithToolchain }}",
          "build": [
            "{{ properties.commandReconfigure }}",
            "{{ properties.commandBuild }}"
          ],
          "clean": "{{ properties.commandClean }}",
          "execute": "{{ properties.commandExecuteHello }}"
        }
      }
    }
  }
}

With a bit of xpm magic, the complete cycle of prepare/build/execute can be reduced to:

cd <project>

xpm install
xpm run test

Note: this example does not require the presence of a compiler in the system, it includes a dependency to xPack GCC and a CMake toolchain description file using it, to prevent CMake picking any other unwanted compiler possibly present in the system.

VS Code configurations

The VS Code C/C++ extension keeps track of multiple configurations in the .vscode/c_cpp_properties.json file, and the xPack extension automatically maps the package.json build configurations to VS Code configurations.

IntelliSense correctly renders the content for the active configurations, shown in the status bar.

Active Configuration

IntelliSense enabled only for top folders

TL;DR: open separate projects/packages as separate workspace folders.

Due to the specifics of the VS Code C/C++ extension, IntelliSense is available only if the package is in the root of the workspace folder.

In other words, when opening a workspace folder which includes multiple packages, IntelliSense will not be enabled.

The correct solution is to open all packages as workspace folders, either separately or via a *.code-workspace file.

IntelliSense available only after the first build

In order to correctly parse the project, for managed projects, IntelliSense needs a file called compile_commands.json. One such file is expected in each build folder, and the system build generator (CMake/meson/etc) automatically creates these files when the project is prepared, like during the first build.

Ignore the kits selection question

Although not needed by the xPack extension, the CMake extension still insists on selecting a kit:

CMake kits

Select Unspecified, since kits are not used by the xPack extension.

This issue is currently under consideration by the CMake Tools project and it is expected to be fixed in a future release.

Known Issues

none so far

Project templates

Creating new projects is automated by using project templates.

Create a Hello World project

The Quick Start a Hello World project presented above creates a C++ project built with CMake.

The full set of choices is available when executing the xPack: Create a Hello World project, which is an interactive applications requiring user input.

The result is similar, but using different build tools or language (C vs C++).

When this command is invoked, VS Code instantiates the separate project template available from:

https://github.com/xpack/hello-world-template-xpack/

Create a Hello World QEMU semihosted project

In addition to native projects running on the host system, it is possible to create Arm Cortex-M, Arm Cortex-A (32/64-bit) and RISC-V (32/64-bit) bare metal projects running on QEMU.