Using IAR Build Tools with CMake Presets

This article brings a configuration approach that enables developers to integrate the IAR C/C++ Compiler toolchain with CMake's preset system.

Helpful Resources

• cmake-presets

Description

CMakePresets.json, introduced in CMake 3.19, is an optional file that should be located at the top-level of your project and allows for reproducible and shareable build configurations without relying on environment variables or command-line arguments. This integration is particularly useful for cross-compilation to architectures like ARM Cortex-M, RISC-V, RL78, and RX, leveraging IAR's high-performance compilers while maintaining CMake's flexibility.

The Presets definition file outline

CMake Presets contain information how to configure, buil and test a project. Below you can see an outline of how it looks like:

{
  "configurePresets": [
    {
      // ...
    }
  ],
  "buildPresets": [
    {
      // ...
    }
  ],
  "testPresets": [
    {
      // ...
    }
  ]
}

Template

Before entering CMake Presets, make sure your compiler is working properly as in the example below (for arm):

echo "int main(){}" | /path/to/iccarm --output /tmp/test.o -

The template below comes pre-configured to work with cxarm-9.70.1 on Linux:

{
    "version": 10,
    "configurePresets": [
        {
            "name": "default",
            "hidden": true,
            "cacheVariables": {
                "CMAKE_EXPORT_COMPILE_COMMANDS":true
            },
            "generator": "Ninja Multi-Config",
            "binaryDir": "${sourceDir}/build"
        },
        {
            "name": "cxarm-linux",
            "displayName": "CXARM",
            "description": "Configure project for CXARM",
            "inherits": "default",
            "condition": {
                "type": "equals",
                "lhs": "${hostSystemName}",
                "rhs": "Linux"
            },
            "environment": {
                "CC":  "/opt/iar/cxarm/arm/bin/iccarm",
                "CXX": "/opt/iar/cxarm/arm/bin/iccarm",
                "ASM": "/opt/iar/cxarm/arm/bin/iasmarm"
            }
        }
    ],
    "buildPresets": [
        {
            "name": "debug",
            "displayName": "Debug",
            "description": "Disable optimizations - include debug information.",
            "configurePreset": "cxarm-linux",
            "configuration": "Debug"
        },
        {
            "name": "release",
            "displayName": "Release",
            "description": "Optimize for speed - exclude debug information.",
            "configurePreset": "cxarm-linux",
            "configuration": "Release"
        },
        {
            "name": "relwithdebinfo",
            "displayName": "RelWithDebInfo",
            "description": "Optimize for speed - include debug information.",
            "configurePreset": "cxarm-linux",
            "configuration": "RelWithDebInfo"
        },
        {
            "name": "minsizerel",
            "displayName": "MinSizeRel",
            "description": "Optimize for smallest binary size - exclude debug information.",
            "configurePreset": "cxarm-linux",
            "configuration": "MinSizeRel"
        }
    ]
}

Building a Project with CMake Presets

Amongst the many ways of building a CMake project with IAR, it is possible to use CMake Presets. The project comes with a preset for cxarm which generates its default build scripts. Below you will find some simple sequence of commands:

# Configure the project (Debug, Release, RelWithDebInfo, MinSizeRel)
$ cmake --preset cxarm

# Build the Debug configuration
$ cmake --build --preset debug

In addition, the CMakePresets.json file is also consumed by the CMake Tools VS Code Extension and integrates well with the lightweight IDE and a more complete example can be seen in modern-workflow.

Summary

CMake presets are a great way to programmatically setup the underlying host environment for use within cross-platform scenarios, even if it is not mandatory for any CMake project per se (e.g., using a toolchain file). The proposed template can be used as an starting point, checked into version control, and extended as needed.