xref: /llvm-project/llvm/unittests/Support/Threading.cpp (revision 89e6a288674c9fae33aeb5448c7b1fe782b2bf53)
1 //===- unittests/Threading.cpp - Thread tests -----------------------------===//
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 #include "llvm/Support/Threading.h"
10 #include "llvm/Config/llvm-config.h" // for LLVM_ENABLE_THREADS
11 #include "llvm/Support/thread.h"
12 #include "llvm/TargetParser/Host.h"
13 #include "llvm/TargetParser/Triple.h"
14 #include "gtest/gtest.h"
15 
16 #include <atomic>
17 #include <condition_variable>
18 
19 using namespace llvm;
20 
21 namespace {
22 
23 static bool isThreadingSupportedArchAndOS() {
24 #if LLVM_ENABLE_THREADS
25   Triple Host(Triple::normalize(sys::getProcessTriple()));
26 
27   // Initially this is only testing detection of the number of
28   // physical cores, which is currently only supported/tested on
29   // some systems.
30   return (Host.isOSWindows() && llvm_is_multithreaded()) || Host.isOSDarwin() ||
31          (Host.isX86() && Host.isOSLinux()) ||
32          (Host.isOSLinux() && !Host.isAndroid()) ||
33          (Host.isSystemZ() && Host.isOSzOS()) || Host.isOSAIX();
34 #else
35   return false;
36 #endif
37 }
38 
39 TEST(Threading, PhysicalConcurrency) {
40   auto Num = heavyweight_hardware_concurrency();
41   // Since Num is unsigned this will also catch us trying to
42   // return -1.
43   ASSERT_LE(Num.compute_thread_count(),
44             hardware_concurrency().compute_thread_count());
45 }
46 
47 TEST(Threading, NumPhysicalCoresSupported) {
48   if (!isThreadingSupportedArchAndOS())
49     GTEST_SKIP();
50   int Num = get_physical_cores();
51   ASSERT_GT(Num, 0);
52 }
53 
54 TEST(Threading, NumPhysicalCoresUnsupported) {
55   if (isThreadingSupportedArchAndOS())
56     GTEST_SKIP();
57   int Num = get_physical_cores();
58   ASSERT_EQ(Num, -1);
59 }
60 
61 #if LLVM_ENABLE_THREADS
62 
63 class Notification {
64 public:
65   void notify() {
66     {
67       std::lock_guard<std::mutex> Lock(M);
68       Notified = true;
69       // Broadcast with the lock held, so it's safe to destroy the Notification
70       // after wait() returns.
71       CV.notify_all();
72     }
73   }
74 
75   bool wait() {
76     std::unique_lock<std::mutex> Lock(M);
77     using steady_clock = std::chrono::steady_clock;
78     auto Deadline = steady_clock::now() +
79                     std::chrono::duration_cast<steady_clock::duration>(
80                         std::chrono::duration<double>(5));
81     return CV.wait_until(Lock, Deadline, [this] { return Notified; });
82   }
83 
84 private:
85   bool Notified = false;
86   mutable std::condition_variable CV;
87   mutable std::mutex M;
88 };
89 
90 TEST(Threading, RunOnThreadSyncAsync) {
91   Notification ThreadStarted, ThreadAdvanced, ThreadFinished;
92 
93   auto ThreadFunc = [&] {
94     ThreadStarted.notify();
95     ASSERT_TRUE(ThreadAdvanced.wait());
96     ThreadFinished.notify();
97   };
98 
99   llvm::thread Thread(ThreadFunc);
100   Thread.detach();
101   ASSERT_TRUE(ThreadStarted.wait());
102   ThreadAdvanced.notify();
103   ASSERT_TRUE(ThreadFinished.wait());
104 }
105 
106 TEST(Threading, RunOnThreadSync) {
107   std::atomic_bool Executed(false);
108   llvm::thread Thread(
109       [](void *Arg) { *static_cast<std::atomic_bool *>(Arg) = true; },
110       &Executed);
111   Thread.join();
112   ASSERT_EQ(Executed, true);
113 }
114 
115 #if defined(__APPLE__)
116 TEST(Threading, AppleStackSize) {
117   llvm::thread Thread([] {
118     volatile unsigned char Var[8 * 1024 * 1024 - 10240];
119     Var[0] = 0xff;
120     ASSERT_EQ(Var[0], 0xff);
121   });
122   Thread.join();
123 }
124 #endif
125 #endif
126 
127 } // namespace
128