LLVM  3.7.0
Threading.cpp
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1 //===-- llvm/Support/Threading.cpp- Control multithreading mode --*- C++ -*-==//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This file defines helper functions for running LLVM in a multi-threaded
11 // environment.
12 //
13 //===----------------------------------------------------------------------===//
14 
15 #include "llvm/Support/Threading.h"
16 #include "llvm/Config/config.h"
17 #include "llvm/Support/Atomic.h"
18 #include "llvm/Support/Mutex.h"
19 #include <cassert>
20 
21 using namespace llvm;
22 
24 #if LLVM_ENABLE_THREADS != 0
25  return true;
26 #else
27  return false;
28 #endif
29 }
30 
31 #if LLVM_ENABLE_THREADS != 0 && defined(HAVE_PTHREAD_H)
32 #include <pthread.h>
33 
34 struct ThreadInfo {
35  void (*UserFn)(void *);
36  void *UserData;
37 };
38 static void *ExecuteOnThread_Dispatch(void *Arg) {
39  ThreadInfo *TI = reinterpret_cast<ThreadInfo*>(Arg);
40  TI->UserFn(TI->UserData);
41  return nullptr;
42 }
43 
44 void llvm::llvm_execute_on_thread(void (*Fn)(void*), void *UserData,
45  unsigned RequestedStackSize) {
46  ThreadInfo Info = { Fn, UserData };
47  pthread_attr_t Attr;
48  pthread_t Thread;
49 
50  // Construct the attributes object.
51  if (::pthread_attr_init(&Attr) != 0)
52  return;
53 
54  // Set the requested stack size, if given.
55  if (RequestedStackSize != 0) {
56  if (::pthread_attr_setstacksize(&Attr, RequestedStackSize) != 0)
57  goto error;
58  }
59 
60  // Construct and execute the thread.
61  if (::pthread_create(&Thread, &Attr, ExecuteOnThread_Dispatch, &Info) != 0)
62  goto error;
63 
64  // Wait for the thread and clean up.
65  ::pthread_join(Thread, nullptr);
66 
67  error:
68  ::pthread_attr_destroy(&Attr);
69 }
70 #elif LLVM_ENABLE_THREADS!=0 && defined(LLVM_ON_WIN32)
71 #include "Windows/WindowsSupport.h"
72 #include <process.h>
73 
74 struct ThreadInfo {
75  void (*func)(void*);
76  void *param;
77 };
78 
79 static unsigned __stdcall ThreadCallback(void *param) {
80  struct ThreadInfo *info = reinterpret_cast<struct ThreadInfo *>(param);
81  info->func(info->param);
82 
83  return 0;
84 }
85 
86 void llvm::llvm_execute_on_thread(void (*Fn)(void*), void *UserData,
87  unsigned RequestedStackSize) {
88  struct ThreadInfo param = { Fn, UserData };
89 
90  HANDLE hThread = (HANDLE)::_beginthreadex(NULL,
91  RequestedStackSize, ThreadCallback,
92  &param, 0, NULL);
93 
94  if (hThread) {
95  // We actually don't care whether the wait succeeds or fails, in
96  // the same way we don't care whether the pthread_join call succeeds
97  // or fails. There's not much we could do if this were to fail. But
98  // on success, this call will wait until the thread finishes executing
99  // before returning.
100  (void)::WaitForSingleObject(hThread, INFINITE);
101  ::CloseHandle(hThread);
102  }
103 }
104 #else
105 // Support for non-Win32, non-pthread implementation.
106 void llvm::llvm_execute_on_thread(void (*Fn)(void*), void *UserData,
107  unsigned RequestedStackSize) {
108  (void) RequestedStackSize;
109  Fn(UserData);
110 }
111 
112 #endif
void * UserData
Definition: Threading.cpp:36
static void * ExecuteOnThread_Dispatch(void *Arg)
Definition: Threading.cpp:38
lazy value info
static std::error_code error(DiagnosticHandlerFunction DiagnosticHandler, std::error_code EC, const Twine &Message)
bool llvm_is_multithreaded()
Returns true if LLVM is compiled with support for multi-threading, and false otherwise.
Definition: Threading.cpp:23
void llvm_execute_on_thread(void(*UserFn)(void *), void *UserData, unsigned RequestedStackSize=0)
llvm_execute_on_thread - Execute the given UserFn on a separate thread, passing it the provided UserD...
Definition: Threading.cpp:44
void(* UserFn)(void *)
Definition: Threading.cpp:35