iPlug2 supports building plugins for Windows ARM64EC (ARM64 Emulation Compatible), enabling native performance on Windows ARM devices while maintaining compatibility with x64 hosts.

What is ARM64EC?

ARM64EC is a Windows ABI that allows ARM64 code to interoperate with x64 code. This is particularly useful for audio plugins because:

Native performance: ARM64EC code runs natively on ARM64 processors
x64 host compatibility: ARM64EC plugins can be loaded by x64 DAWs running under emulation
Gradual migration: Allows mixing ARM64 and x64 code in the same process

This means you can ship ARM64EC plugins that will:

Run at full native speed when loaded by ARM64 native hosts
Still work when loaded by x64 hosts (DAWs) running under emulation on ARM64 Windows

Supported Platforms

ARM64EC builds are supported for:

Plugin Formats: VST2, VST3, CLAP, AAX, Standalone App
Graphics Backend: NanoVG only (Skia not yet supported for ARM64EC)

Building for ARM64EC

Visual Studio Requirements

ARM64EC builds require:

Visual Studio 2022 (v17.0+)
ARM64EC build tools installed via Visual Studio Installer

Installing ARM64EC Build Tools

Open Visual Studio Installer
Click Modify on your Visual Studio 2022 installation
Go to Individual Components
Search for "ARM64EC" and install:
- MSVC v143 - VS 2022 C++ ARM64EC build tools (Latest)

Cross-Compilation

ARM64EC builds use cross-compilation from an x64 host. When building from command line, the build environment must be initialized for ARM64 cross-compilation:

:: Initialize environment for ARM64EC cross-compilation
call "C:\Program Files\Microsoft Visual Studio\2022\Professional\VC\Auxiliary\Build\vcvarsall.bat" amd64_arm64
 
:: Then build
msbuild YourPlugin.sln /p:Configuration=Release /p:Platform=ARM64EC

The amd64_arm64 argument tells vcvarsall to set up the x64-hosted ARM64 cross-compiler toolchain, which is used for ARM64EC builds.

‍Note: You can verify the ARM64EC tools are installed by checking if vswhere finds them:
& "${env:ProgramFiles(x86)}\Microsoft Visual Studio\Installer\vswhere.exe" -latest -requires Microsoft.VisualStudio.Component.VC.Tools.ARM64EC -property installationPath

Build Configurations

Each iPlug2 solution includes ARM64EC configurations alongside x64:

Configuration	Platform	Description
Debug	x64	Debug build for x64
Debug	ARM64EC	Debug build for ARM64EC
Release	x64	Release build for x64
Release	ARM64EC	Release build for ARM64EC
Tracer	x64	Tracer build for x64
Tracer	ARM64EC	Tracer build for ARM64EC

Building from Visual Studio

Open the solution file (e.g., IPlugEffect.sln)
Select the desired configuration (Debug/Release/Tracer)
Select the platform (ARM64EC)
Build the solution

Building from Command Line

msbuild YourPlugin.sln /p:Configuration=Release /p:Platform=ARM64EC

Debugger Configuration

Debugger settings are configured via MSBuild properties in common-win.props. The following variables control debugger host paths:

x64 Variables

VST2_X64_HOST_PATH - Host application for x64 VST2 debugging
VST3_X64_HOST_PATH - Host application for x64 VST3 debugging
CLAP_X64_HOST_PATH - Host application for x64 CLAP debugging

ARM64EC Variables

VST2_ARM64EC_HOST_PATH - Host application for ARM64EC VST2 debugging
VST3_ARM64EC_HOST_PATH - Host application for ARM64EC VST3 debugging
CLAP_ARM64EC_HOST_PATH - Host application for ARM64EC CLAP debugging

Plugin Output Paths

VST3_X64_PATH - Installation path for x64 VST3 plugins
VST3_ARM64EC_PATH - Installation path for ARM64EC VST3 plugins
CLAP_X64_PATH - Installation path for x64 CLAP plugins
CLAP_ARM64EC_PATH - Installation path for ARM64EC CLAP plugins

Output File Naming

Built binaries use platform suffixes:

Format	x64 Output	ARM64EC Output
VST2	`PluginName_x64.dll`	`PluginName_ARM64EC.dll`
VST3	`PluginName.vst3/Contents/x86_64-win/`	`PluginName.vst3/Contents/arm64ec-win/`
CLAP	`PluginName.clap`	`PluginName.clap` (in ARM64EC folder)
APP	`PluginName_x64.exe`	`PluginName_ARM64EC.exe`

Skia Limitation

ARM64EC builds are automatically skipped when ‘graphics: 'SKIA’` is specified, as Skia does not yet support ARM64EC on Windows.

Known Limitations

Skia graphics: Not yet supported for ARM64EC. Use NanoVG for ARM64EC builds.
Testing on x64 machines: ARM64EC binaries cannot be executed on x64 Windows. Testing requires ARM64 Windows hardware or emulation.
AAX: ARM64EC AAX support depends on Avid's AAX SDK support for ARM64EC.

VST3 Bundle Structure

VST3 plugins support multi-architecture bundles. After building both architectures, the bundle structure is:

PluginName.vst3/
├── Contents/
│   ├── x86_64-win/
│   │   └── PluginName.vst3
│   └── arm64ec-win/
│       └── PluginName.vst3
└── Resources/
    └── ...

This allows a single VST3 bundle to contain both x64 and ARM64EC binaries, with the host selecting the appropriate one at runtime.