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
llvm_is_multithreaded()23 bool llvm::llvm_is_multithreaded() {
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 };
ExecuteOnThread_Dispatch(void * Arg)38 static void *ExecuteOnThread_Dispatch(void *Arg) {
39 ThreadInfo *TI = reinterpret_cast<ThreadInfo*>(Arg);
40 TI->UserFn(TI->UserData);
41 return nullptr;
42 }
43
llvm_execute_on_thread(void (* Fn)(void *),void * UserData,unsigned RequestedStackSize)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
ThreadCallback(void * param)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
llvm_execute_on_thread(void (* Fn)(void *),void * UserData,unsigned RequestedStackSize)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 ¶m, 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.
llvm_execute_on_thread(void (* Fn)(void *),void * UserData,unsigned RequestedStackSize)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
113