Introduced in OpenMP 6.0, the device UID shall be a unique identifier of a device on a given system. (Not necessarily a UUID.) Since it is not guaranteed that the (U)UIDs defined by the device vendor libraries, such as HSA, do not overlap with those of other vendors, the device UIDs in offload are always combined with the offload plugin name. In case the vendor library does not specify any device UID for a given device, we fall back to the offload-internal device ID. The device UID can be retrieved using the `llvm-offload-device-info` tool.
Liboffload
This directory contains the implementation of the work-in-progress new API for Offload. It builds on top of the existing plugin implementations but provides a single level of abstraction suitable for implementation of many offloading language runtimes, rather than just OpenMP.
Testing liboffload
The main test suite for liboffload can be run with the check-offload-unit
target, which runs the offload.unittests executable. The test suite will
automatically run on every available device, but can be restricted to a single
platform (CUDA, AMDGPU) with a command line argument:
$ ./offload.unittests --platform=CUDA
Tracing of Offload API calls can be enabled by setting the OFFLOAD_TRACE
environment variable. This works with any program that uses liboffload.
$ OFFLOAD_TRACE=1 ./offload.unittests
---> olInit()-> OL_SUCCESS
# etc
The host plugin is not currently supported.
Modifying liboffload
The main header (OffloadAPI.h) and some implementation details are
autogenerated with tablegen. See the API definition README
for implementation details.