[clang] Add the ability to link libclc OpenCL libraries (#146503)

This commit adds driver support for linking libclc OpenCL libraries. It
takes the form of a new optional flag: --libclc-lib=namespec. Nothing is
linked unless this flag is specified.

Not all libclc targets have corresponding clang targets. For this reason
it is desirable for users to be able to specify a libclc library name.
We support this by taking both a library name (without the .bc suffix)
or a filename. Both of these are searched for in the clang resource
directory. Filenames are
also checked themselves so that absolute paths can be provided. The
syntax for specifying filenames (as opposed to library names) uses a
leading colon (:), inspired by the -l option.

To accommodate this option, libclc libraries are now placed into clang's
resource directory in an in-tree configuration. The libraries are all
placed in <resource-dir>/lib/libclc and
are not grouped under host-specific directories as some other runtime
libraries are; it is not expected that OpenCL libraries will differ
depending on the host toolchain.

Currently only the AMDGPU toolchain supports this option as a proof of
concept. Other targets such as NVPTX or SPIR/SPIR-V could support it
too. We could optionally let target toolchains search for libclc
libraries themselves, possibly when passed an empty --libclc-lib.

0 files changed, 0 insertions, 0 deletions