e537c83975
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
55 lines
1.5 KiB
C
55 lines
1.5 KiB
C
// RUN: %libomptarget-compile-run-and-check-generic
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// REQUIRES: libc
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#include <assert.h>
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#include <omp.h>
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#include <stdio.h>
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#pragma omp begin declare variant match(device = {kind(gpu)})
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// Extension provided by the 'libc' project.
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void rpc_host_call(void *fn, void *args, size_t size);
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#pragma omp declare target to(rpc_host_call) device_type(nohost)
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#pragma omp end declare variant
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#pragma omp begin declare variant match(device = {kind(cpu)})
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// Dummy host implementation to make this work for all targets.
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void rpc_host_call(void *fn, void *args, size_t size) {
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((void (*)(void *))fn)(args);
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}
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#pragma omp end declare variant
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typedef struct args_s {
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int thread_id;
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int block_id;
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} args_t;
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// CHECK-DAG: Thread: 0, Block: 0
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// CHECK-DAG: Thread: 1, Block: 0
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// CHECK-DAG: Thread: 0, Block: 1
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// CHECK-DAG: Thread: 1, Block: 1
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// CHECK-DAG: Thread: 0, Block: 2
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// CHECK-DAG: Thread: 1, Block: 2
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// CHECK-DAG: Thread: 0, Block: 3
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// CHECK-DAG: Thread: 1, Block: 3
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void foo(void *data) {
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assert(omp_is_initial_device() && "Not executing on host?");
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args_t *args = (args_t *)data;
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printf("Thread: %d, Block: %d\n", args->thread_id, args->block_id);
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}
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void *fn_ptr = NULL;
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#pragma omp declare target to(fn_ptr)
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int main() {
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fn_ptr = (void *)&foo;
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#pragma omp target update to(fn_ptr)
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#pragma omp target teams num_teams(4)
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#pragma omp parallel num_threads(2)
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{
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args_t args = {omp_get_thread_num(), omp_get_team_num()};
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rpc_host_call(fn_ptr, &args, sizeof(args_t));
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}
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}
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