1 //===-------- Tasking.cpp - NVPTX OpenMP tasks support ------------ C++ -*-===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // Task implementation support.
10 //
11 // TODO: We should not allocate and execute the task in two steps. A new API is
12 //       needed for that though.
13 //
14 //===----------------------------------------------------------------------===//
15 
16 #include "Interface.h"
17 #include "State.h"
18 #include "Types.h"
19 #include "Utils.h"
20 
21 using namespace _OMP;
22 
23 #pragma omp declare target
24 
25 TaskDescriptorTy *__kmpc_omp_task_alloc(IdentTy *, uint32_t, int32_t,
26                                         uint64_t TaskSizeInclPrivateValues,
27                                         uint64_t SharedValuesSize,
28                                         TaskFnTy TaskFn) {
29   auto TaskSizeInclPrivateValuesPadded =
30       utils::roundUp(TaskSizeInclPrivateValues, uint64_t(sizeof(void *)));
31   auto TaskSizeTotal = TaskSizeInclPrivateValuesPadded + SharedValuesSize;
32   TaskDescriptorTy *TaskDescriptor = (TaskDescriptorTy *)memory::allocGlobal(
33       TaskSizeTotal, "explicit task descriptor");
34   TaskDescriptor->Payload =
35       utils::advance(TaskDescriptor, TaskSizeInclPrivateValuesPadded);
36   TaskDescriptor->TaskFn = TaskFn;
37 
38   return TaskDescriptor;
39 }
40 
41 int32_t __kmpc_omp_task(IdentTy *Loc, uint32_t TId,
42                         TaskDescriptorTy *TaskDescriptor) {
43   return __kmpc_omp_task_with_deps(Loc, TId, TaskDescriptor, 0, 0, 0, 0);
44 }
45 
46 int32_t __kmpc_omp_task_with_deps(IdentTy *Loc, uint32_t TId,
47                                   TaskDescriptorTy *TaskDescriptor, int32_t,
48                                   void *, int32_t, void *) {
49   state::DateEnvironmentRAII DERAII;
50 
51   TaskDescriptor->TaskFn(0, TaskDescriptor);
52 
53   memory::freeGlobal(TaskDescriptor, "explicit task descriptor");
54   return 0;
55 }
56 
57 void __kmpc_omp_task_begin_if0(IdentTy *Loc, uint32_t TId,
58                                TaskDescriptorTy *TaskDescriptor) {
59   state::enterDataEnvironment();
60 }
61 
62 void __kmpc_omp_task_complete_if0(IdentTy *Loc, uint32_t TId,
63                                   TaskDescriptorTy *TaskDescriptor) {
64   state::exitDataEnvironment();
65 
66   memory::freeGlobal(TaskDescriptor, "explicit task descriptor");
67 }
68 
69 void __kmpc_omp_wait_deps(IdentTy *Loc, uint32_t TId, int32_t, void *, int32_t,
70                           void *) {}
71 
72 void __kmpc_taskgroup(IdentTy *Loc, uint32_t TId) {}
73 
74 void __kmpc_end_taskgroup(IdentTy *Loc, uint32_t TId) {}
75 
76 int32_t __kmpc_omp_taskyield(IdentTy *Loc, uint32_t TId, int) { return 0; }
77 
78 int32_t __kmpc_omp_taskwait(IdentTy *Loc, uint32_t TId) { return 0; }
79 
80 void __kmpc_taskloop(IdentTy *Loc, uint32_t TId,
81                      TaskDescriptorTy *TaskDescriptor, int,
82                      uint64_t *LowerBound, uint64_t *UpperBound, int64_t, int,
83                      int32_t, uint64_t, void *) {
84   // Skip task entirely if empty iteration space.
85   if (*LowerBound > *UpperBound)
86     return;
87 
88   // The compiler has already stored lb and ub in the TaskDescriptorTy structure
89   // as we are using a single task to execute the entire loop, we can leave
90   // the initial task_t untouched
91   __kmpc_omp_task_with_deps(Loc, TId, TaskDescriptor, 0, 0, 0, 0);
92 }
93 
94 int omp_in_final(void) {
95   // treat all tasks as final... Specs may expect runtime to keep
96   // track more precisely if a task was actively set by users... This
97   // is not explicitly specified; will treat as if runtime can
98   // actively decide to put a non-final task into a final one.
99   return 1;
100 }
101 
102 int omp_get_max_task_priority(void) { return 0; }
103 
104 #pragma omp end declare target
105