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author | Joseph Huber <jhuber6@vols.utk.edu> | 2023-07-11 14:14:08 -0500 |
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committer | Joseph Huber <jhuber6@vols.utk.edu> | 2023-07-19 10:11:46 -0500 |
commit | e537c839757c6bae91bd5adbf65eb4e06a040840 (patch) | |
tree | 207463a9bfa36bcbffc343046a7843b8e16b9fca /libc/src/gpu/rpc_host_call.cpp | |
parent | 68cd1dbc2ec97e20306694a7cdc480584295e62c (diff) | |
download | llvm-e537c839757c6bae91bd5adbf65eb4e06a040840.zip llvm-e537c839757c6bae91bd5adbf65eb4e06a040840.tar.gz llvm-e537c839757c6bae91bd5adbf65eb4e06a040840.tar.bz2 |
[libc] Add basic support for calling host functions from the GPU
This patch adds the `rpc_host_call` function as a GPU extension. This is
exported from the `libc` project to use the RPC interface to call a
function pointer via RPC any copying the arguments by-value. The
interface can only support a single void pointer argument much like
pthreads. The function call here is the bare-bones version of what's
required for OpenMP reverse offloading. Full support will require
interfacing with the mapping table, nowait support, etc.
I decided to test this interface in `libomptarget` as that will be the
primary consumer and it would be more difficult to make a test in `libc`
due to the testing infrastructure not really having a concept of the
"host" as it runs directly on the GPU as if it were a CPU target.
Reviewed By: jplehr
Differential Revision: https://reviews.llvm.org/D155003
Diffstat (limited to 'libc/src/gpu/rpc_host_call.cpp')
-rw-r--r-- | libc/src/gpu/rpc_host_call.cpp | 30 |
1 files changed, 30 insertions, 0 deletions
diff --git a/libc/src/gpu/rpc_host_call.cpp b/libc/src/gpu/rpc_host_call.cpp new file mode 100644 index 0000000..67b839d --- /dev/null +++ b/libc/src/gpu/rpc_host_call.cpp @@ -0,0 +1,30 @@ +//===---------- GPU implementation of the external RPC call function ------===// +// +// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. +// See https://llvm.org/LICENSE.txt for license information. +// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception +// +//===----------------------------------------------------------------------===// + +#include "src/gpu/rpc_host_call.h" + +#include "llvm-libc-types/rpc_opcodes_t.h" +#include "src/__support/GPU/utils.h" +#include "src/__support/RPC/rpc_client.h" +#include "src/__support/common.h" + +namespace __llvm_libc { + +// This calls the associated function pointer on the RPC server with the given +// arguments. We expect that the pointer here is a valid pointer on the server. +LLVM_LIBC_FUNCTION(void, rpc_host_call, (void *fn, void *data, size_t size)) { + rpc::Client::Port port = rpc::client.open<RPC_HOST_CALL>(); + port.send_n(data, size); + port.send([=](rpc::Buffer *buffer) { + buffer->data[0] = reinterpret_cast<uintptr_t>(fn); + }); + port.recv([](rpc::Buffer *) {}); + port.close(); +} + +} // namespace __llvm_libc |