In order to do offloading compilation we need to embed files into the
host and create fatbainaries. Clang uses a special binary format to
bundle several files along with their metadata into a single binary
image. This is currently performed using the `-fembed-offload-binary`
option. However this is not very extensibile since it requires changing
the command flag every time we want to add something and makes optional
arguments difficult. This patch introduces a new tool called
`clang-offload-packager` that behaves similarly to CUDA's `fatbinary`.
This tool takes several input files with metadata and embeds it into a
single image that can then be embedded in the host.
Reviewed By: tra
Differential Revision: https://reviews.llvm.org/D125165
This patch adds support for OpenMP to use the `--offload-arch` and
`--no-offload-arch` options. Traditionally, OpenMP has only supported
compiling for a single architecture via the `-Xopenmp-target` option.
Now we can pass in a bound architecture and use that if given, otherwise
we default to the value of the `-march` option as before.
Note that this only applies the basic support, the OpenMP target runtime
does not yet know how to choose between multiple architectures.
Additionally other parts of the offloading toolchain (e.g. LTO) require
the `-march` option, these should be worked out later.
Reviewed By: tra
Differential Revision: https://reviews.llvm.org/D124721
Previously an opt-in flag `-fopenmp-new-driver` was used to enable the
new offloading driver. After passing tests for a few months it should be
sufficiently mature to flip the switch and make it the default. The new
offloading driver is now enabled if there is OpenMP and OpenMP
offloading present and the new `-fno-openmp-new-driver` is not present.
The new offloading driver has three main benefits over the old method:
- Static library support
- Device-side LTO
- Unified clang driver stages
Depends on D122683
Differential Revision: https://reviews.llvm.org/D122831
Joseph Huber