LLVM Embedded Toolchain for Arm

The LLVM Embedded Toolchain for Arm allows Cortex-M developers to build projects with the clang compiler.

Pre-built binaries are available for Windows (x86_64), macOS (x86_64 and Apple Silicon), and Linux (x86_64 and AArch64) hosts.

Install the LLVM Embedded Toolchain for Arm on Windows

To download the latest release from GitHub, copy and paste the following URL into your browser:

    

        
        
https://github.com/ARM-software/LLVM-embedded-toolchain-for-Arm/releases/download/release-19.1.5/LLVM-ET-Arm-19.1.5-Windows-x86_64.zip

    

Unzip the download to a location of your choice on your host machine.

Open Windows Control Panel and add the LLVM bin directory to the Path.

Open a Command Prompt and test your installation .

Install the LLVM Embedded Toolchain for Arm on macOS

To download the latest release from GitHub, copy and paste the following URL into your browser:

    

        
        
https://github.com/ARM-software/LLVM-embedded-toolchain-for-Arm/releases/download/release-19.1.5/LLVM-ET-Arm-19.1.5-Darwin-universal.dmg

    

Install the toolchain by clicking the dmg file and following the instructions.

Add the LLVM bin directory to your PATH:

    

        
        
export PATH=/Applications/LLVM-ET-Arm-19.1.5-Darwin-universal/bin:$PATH

    

The toolchain binaries might be quarantined. Navigate to the bin directory and use the xattr command to remove the quarantine:

    

        
        
cd /Applications/LLVM-ET-Arm-19.1.5-Darwin-universal/bin
find . -type f -perm +0111 | xargs xattr -d com.apple.quarantine

    

You can now test your installation .

Install the LLVM Embedded Toolchain for Arm on Linux

The following steps assume Ubuntu Linux on an AArch64 host. Modify the filenames and paths as needed for other hosts.

Download the latest release using wget:

    

        
        
wget https://github.com/ARM-software/LLVM-embedded-toolchain-for-Arm/releases/download/release-19.1.5/LLVM-ET-Arm-19.1.5-Linux-AArch64.tar.xz

    

Open a terminal application and use tar to extract the file:

    

        
        
tar xfJ LLVM-ET-Arm-19.1.5-Linux-AArch64.tar.xz -C $HOME

    

Add the LLVM bin directory to your PATH:

    

        
        
export PATH=$HOME/LLVM-ET-Arm-19.1.5-Linux-AArch64/bin:$PATH

    

Test the LLVM Embedded Toolchain installation

You can now test your installation.

Verify the clang installation

Use the --version option to verify the correct compiler is being invoked:

    

        
        
clang --version

    

The output is similar to:

    

        
        clang version 19.1.5
Target: aarch64-unknown-linux-gnu
Thread model: posix
InstalledDir: /home/ubuntu/LLVM-ET-Arm-19.1.5-Linux-AArch64/bin

        
    

Build a sample application with clang

Use a text editor to create an example source file with the name hello.c and the following code:

    

        
        
#include <stdio.h>

int main()
{
  printf("hello");
  return 0;
}

    

A number of compiler options are needed. For more information, see Using the toolchain .

To build for Armv6-M, run:

    

        
        
clang --target=armv6m-none-eabi -fno-exceptions -fno-rtti -lcrt0-semihost -lsemihost -T picolibc.ld -o hello_v6m hello.c

    

To build for Armv7-M, run:

    

        
        
clang --target=armv7m-none-eabi -fno-exceptions -fno-rtti -lcrt0-semihost -lsemihost -T picolibc.ld -o hello_v7m hello.c

    

Run the example applications

The applications can be run on Fixed Virtual Platforms (FVP) .

To run the Armv6-M example on Cortex-M0 FVP:

    

        
        
FVP_MPS2_Cortex-M0 -a hello_v6m

    

To run the Armv7-M example on Cortex-M3 FVP:

    

        
        
FVP_MPS2_Cortex-M3 -a hello_v7m

    

You’ll see the hello message on the console, as well as other diagnostic output from the FVP:

    

        
        telnetterminal1: Listening for serial connection on port 5000
telnetterminal2: Listening for serial connection on port 5002
telnetterminal0: Listening for serial connection on port 5001
hello
Info: /OSCI/SystemC: Simulation stopped by user.

        
    

You’re now ready to use LLVM Embedded Toolchain for Arm.