IAR Arm Toolchain - Zephyr

.. _toolchain_iar_arm:

IAR Arm Toolchain #################

#. Download and install a release v9.70 or newer of IAR Arm Toolchain_ on your host (IAR Embedded Workbench or IAR Build Tools, perpetual or subscription licensing)

#. Make sure you have :ref:Zephyr SDK <toolchain_zephyr_sdk> installed on your host.

#. :ref:Set these environment variables <env_vars>:

- Set :envvar:`ZEPHYR_TOOLCHAIN_VARIANT` to ``iar``.
- Set :envvar:`IAR_TOOLCHAIN_PATH` to the toolchain installation directory.

#. The cloud licensed variant of the IAR Toolchain needs the :envvar:IAR_LMS_BEARER_TOKEN environment variable to be set to a valid license bearer token (subscription licensing).

For example:

.. code-block:: bash

# Linux (default installation path):
export IAR_TOOLCHAIN_PATH=/opt/iar/cxarm-<version>/arm
export ZEPHYR_TOOLCHAIN_VARIANT=iar
export IAR_LMS_BEARER_TOKEN="<BEARER-TOKEN>"

.. code-block:: batch

# Windows:
set IAR_TOOLCHAIN_PATH=c:\<path>\cxarm-<version>\arm
set ZEPHYR_TOOLCHAIN_VARIANT=iar
set IAR_LMS_BEARER_TOKEN="<BEARER-TOKEN>"

.. note::

Known limitations:

- The IAR Toolchain uses ``ilink`` for linking and depends on Zephyr’s CMAKE_LINKER_GENERATOR. ``ilink`` is incompatible with Zephyr’s linker script template, which works with GNU ld.

- The GNU Assembler distributed with the Zephyr SDK is used for ``.S-files``.

- C library support for ``Minimal libc`` only. C++ is not supported.

- Some Zephyr subsystems or modules may contain C or assembly code that relies on GNU intrinsics and have not yet been updated to work fully with ``iar``.

- TrustedFirmware is not supported

.. _IAR Arm Toolchain: https://www.iar.com/products/architectures/arm/