1 //===--------- TaskDispatch.h - ORC task dispatch utils ---------*- 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 and TaskDispatch classes.
10 //
11 //===----------------------------------------------------------------------===//
12
13 #ifndef LLVM_EXECUTIONENGINE_ORC_TASKDISPATCH_H
14 #define LLVM_EXECUTIONENGINE_ORC_TASKDISPATCH_H
15
16 #include "llvm/Config/llvm-config.h"
17 #include "llvm/Support/Debug.h"
18 #include "llvm/Support/ExtensibleRTTI.h"
19 #include "llvm/Support/raw_ostream.h"
20
21 #include <cassert>
22 #include <string>
23
24 #if LLVM_ENABLE_THREADS
25 #include <condition_variable>
26 #include <mutex>
27 #include <thread>
28 #endif
29
30 namespace llvm {
31 namespace orc {
32
33 /// Represents an abstract task for ORC to run.
34 class Task : public RTTIExtends<Task, RTTIRoot> {
35 public:
36 static char ID;
37
~Task()38 virtual ~Task() {}
39
40 /// Description of the task to be performed. Used for logging.
41 virtual void printDescription(raw_ostream &OS) = 0;
42
43 /// Run the task.
44 virtual void run() = 0;
45
46 private:
47 void anchor() override;
48 };
49
50 /// Base class for generic tasks.
51 class GenericNamedTask : public RTTIExtends<GenericNamedTask, Task> {
52 public:
53 static char ID;
54 static const char *DefaultDescription;
55 };
56
57 /// Generic task implementation.
58 template <typename FnT> class GenericNamedTaskImpl : public GenericNamedTask {
59 public:
GenericNamedTaskImpl(FnT && Fn,std::string DescBuffer)60 GenericNamedTaskImpl(FnT &&Fn, std::string DescBuffer)
61 : Fn(std::forward<FnT>(Fn)), Desc(DescBuffer.c_str()),
62 DescBuffer(std::move(DescBuffer)) {}
GenericNamedTaskImpl(FnT && Fn,const char * Desc)63 GenericNamedTaskImpl(FnT &&Fn, const char *Desc)
64 : Fn(std::forward<FnT>(Fn)), Desc(Desc) {
65 assert(Desc && "Description cannot be null");
66 }
printDescription(raw_ostream & OS)67 void printDescription(raw_ostream &OS) override { OS << Desc; }
run()68 void run() override { Fn(); }
69
70 private:
71 FnT Fn;
72 const char *Desc;
73 std::string DescBuffer;
74 };
75
76 /// Create a generic named task from a std::string description.
77 template <typename FnT>
makeGenericNamedTask(FnT && Fn,std::string Desc)78 std::unique_ptr<GenericNamedTask> makeGenericNamedTask(FnT &&Fn,
79 std::string Desc) {
80 return std::make_unique<GenericNamedTaskImpl<FnT>>(std::forward<FnT>(Fn),
81 std::move(Desc));
82 }
83
84 /// Create a generic named task from a const char * description.
85 template <typename FnT>
86 std::unique_ptr<GenericNamedTask>
87 makeGenericNamedTask(FnT &&Fn, const char *Desc = nullptr) {
88 if (!Desc)
89 Desc = GenericNamedTask::DefaultDescription;
90 return std::make_unique<GenericNamedTaskImpl<FnT>>(std::forward<FnT>(Fn),
91 Desc);
92 }
93
94 /// Abstract base for classes that dispatch ORC Tasks.
95 class TaskDispatcher {
96 public:
97 virtual ~TaskDispatcher();
98
99 /// Run the given task.
100 virtual void dispatch(std::unique_ptr<Task> T) = 0;
101
102 /// Called by ExecutionSession. Waits until all tasks have completed.
103 virtual void shutdown() = 0;
104 };
105
106 /// Runs all tasks on the current thread.
107 class InPlaceTaskDispatcher : public TaskDispatcher {
108 public:
109 void dispatch(std::unique_ptr<Task> T) override;
110 void shutdown() override;
111 };
112
113 #if LLVM_ENABLE_THREADS
114
115 class DynamicThreadPoolTaskDispatcher : public TaskDispatcher {
116 public:
117 void dispatch(std::unique_ptr<Task> T) override;
118 void shutdown() override;
119 private:
120 std::mutex DispatchMutex;
121 bool Running = true;
122 size_t Outstanding = 0;
123 std::condition_variable OutstandingCV;
124 };
125
126 #endif // LLVM_ENABLE_THREADS
127
128 } // End namespace orc
129 } // End namespace llvm
130
131 #endif // LLVM_EXECUTIONENGINE_ORC_TASKDISPATCH_H
132