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 begin declare target device_type(nohost)
24 
25 TaskDescriptorTy *__kmpc_omp_task_alloc(IdentTy *, uint32_t, int32_t,
26                                         uint64_t TaskSizeInclPrivateValues,
27                                         uint64_t SharedValuesSize,
28                                         TaskFnTy TaskFn) {
29   FunctionTracingRAII();
30   auto TaskSizeInclPrivateValuesPadded =
31       utils::roundUp(TaskSizeInclPrivateValues, uint64_t(sizeof(void *)));
32   auto TaskSizeTotal = TaskSizeInclPrivateValuesPadded + SharedValuesSize;
33   TaskDescriptorTy *TaskDescriptor = (TaskDescriptorTy *)memory::allocGlobal(
34       TaskSizeTotal, "explicit task descriptor");
35   TaskDescriptor->Payload =
36       utils::advance(TaskDescriptor, TaskSizeInclPrivateValuesPadded);
37   TaskDescriptor->TaskFn = TaskFn;
38 
39   return TaskDescriptor;
40 }
41 
42 int32_t __kmpc_omp_task(IdentTy *Loc, uint32_t TId,
43                         TaskDescriptorTy *TaskDescriptor) {
44   FunctionTracingRAII();
45   return __kmpc_omp_task_with_deps(Loc, TId, TaskDescriptor, 0, 0, 0, 0);
46 }
47 
48 int32_t __kmpc_omp_task_with_deps(IdentTy *Loc, uint32_t TId,
49                                   TaskDescriptorTy *TaskDescriptor, int32_t,
50                                   void *, int32_t, void *) {
51   FunctionTracingRAII();
52   state::DateEnvironmentRAII DERAII(Loc);
53 
54   TaskDescriptor->TaskFn(0, TaskDescriptor);
55 
56   memory::freeGlobal(TaskDescriptor, "explicit task descriptor");
57   return 0;
58 }
59 
60 void __kmpc_omp_task_begin_if0(IdentTy *Loc, uint32_t TId,
61                                TaskDescriptorTy *TaskDescriptor) {
62   FunctionTracingRAII();
63   state::enterDataEnvironment(Loc);
64 }
65 
66 void __kmpc_omp_task_complete_if0(IdentTy *Loc, uint32_t TId,
67                                   TaskDescriptorTy *TaskDescriptor) {
68   FunctionTracingRAII();
69   state::exitDataEnvironment();
70 
71   memory::freeGlobal(TaskDescriptor, "explicit task descriptor");
72 }
73 
74 void __kmpc_omp_wait_deps(IdentTy *Loc, uint32_t TId, int32_t, void *, int32_t,
75                           void *) {
76   FunctionTracingRAII();
77 }
78 
79 void __kmpc_taskgroup(IdentTy *Loc, uint32_t TId) { FunctionTracingRAII(); }
80 
81 void __kmpc_end_taskgroup(IdentTy *Loc, uint32_t TId) { FunctionTracingRAII(); }
82 
83 int32_t __kmpc_omp_taskyield(IdentTy *Loc, uint32_t TId, int) {
84   FunctionTracingRAII();
85   return 0;
86 }
87 
88 int32_t __kmpc_omp_taskwait(IdentTy *Loc, uint32_t TId) {
89   FunctionTracingRAII();
90   return 0;
91 }
92 
93 void __kmpc_taskloop(IdentTy *Loc, uint32_t TId,
94                      TaskDescriptorTy *TaskDescriptor, int,
95                      uint64_t *LowerBound, uint64_t *UpperBound, int64_t, int,
96                      int32_t, uint64_t, void *) {
97   FunctionTracingRAII();
98   // Skip task entirely if empty iteration space.
99   if (*LowerBound > *UpperBound)
100     return;
101 
102   // The compiler has already stored lb and ub in the TaskDescriptorTy structure
103   // as we are using a single task to execute the entire loop, we can leave
104   // the initial task_t untouched
105   __kmpc_omp_task_with_deps(Loc, TId, TaskDescriptor, 0, 0, 0, 0);
106 }
107 
108 int omp_in_final(void) {
109   // treat all tasks as final... Specs may expect runtime to keep
110   // track more precisely if a task was actively set by users... This
111   // is not explicitly specified; will treat as if runtime can
112   // actively decide to put a non-final task into a final one.
113   return 1;
114 }
115 
116 int omp_get_max_task_priority(void) { return 0; }
117 
118 #pragma omp end declare target
119