Ahead of Time Compilation

Ahead of Time (AOT) Compilation is a feature that is helpful in your development lifecycle or distribution time, when you know beforehand what your target device is going to be at application execution time. The AOT feature provides the following benefits:

Note

The program built with AOT compilation for a specific target device will not run on a non-specific device. You must detect the proper target device at runtime and report an error if the targeted device is not present. The use of exception handling with an asynchronous exception handler is recommended.

Data Parallel C++ (DPC++) supports AOT compilation for the following targets: Intel® CPUs, Intel® Processor Graphics (Gen9 or above), and Intel® FPGA.

Prerequisites

To use the AOT feature for targeting a GPU, you must have the OCLOC tool installed. Refer to the Intel® oneAPI Toolkit Installation Guide's section: Install OpenCL™ Offline Compiler (OCLOC) to install the tool on your operating system.

How to Use AOT for the Target Device (Intel® CPUs)

The supported options are:

Examples:

Building an Application with Multiple Source Files for CPU Targeting

Method 1: Compile your normal files (with no DPC++ kernels) first to create host objects. Then compile the file with the kernel code, and link it with the rest of the application in one command line.

Method 2: Compile the file with the kernel code first, and create a fat object. Then compile the rest of the files, and do the linking in one command line to create a fat executable:

Note

Currently, Method 2 only works on a HOST selector.

How to Use AOT for Intel® Integrated Graphics (Intel® GPU)

The supported options are:

To see all the device types, use the following command:

ocloc compile --help

If multiple target devices are listed, the Intel® oneAPI DPC++/C++ Compiler compiles for each of these targets and creates a fat-binary that contains all of the device binaries produced this way.

Examples of supported -device patterns: