xref: /llvm-project/llvm/unittests/Support/Threading.cpp (revision 48c68a630e06666101c16aa371f9202a4a53438b)
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/Support/thread.h"
11 #include "gtest/gtest.h"
12 
13 #include <atomic>
14 #include <condition_variable>
15 
16 using namespace llvm;
17 
18 namespace {
19 
20 TEST(Threading, PhysicalConcurrency) {
21   auto Num = heavyweight_hardware_concurrency();
22   // Since Num is unsigned this will also catch us trying to
23   // return -1.
24   ASSERT_LE(Num.compute_thread_count(),
25             hardware_concurrency().compute_thread_count());
26 }
27 
28 #if LLVM_ENABLE_THREADS
29 
30 class Notification {
31 public:
32   void notify() {
33     {
34       std::lock_guard<std::mutex> Lock(M);
35       Notified = true;
36       // Broadcast with the lock held, so it's safe to destroy the Notification
37       // after wait() returns.
38       CV.notify_all();
39     }
40   }
41 
42   bool wait() {
43     std::unique_lock<std::mutex> Lock(M);
44     using steady_clock = std::chrono::steady_clock;
45     auto Deadline = steady_clock::now() +
46                     std::chrono::duration_cast<steady_clock::duration>(
47                         std::chrono::duration<double>(5));
48     return CV.wait_until(Lock, Deadline, [this] { return Notified; });
49   }
50 
51 private:
52   bool Notified = false;
53   mutable std::condition_variable CV;
54   mutable std::mutex M;
55 };
56 
57 TEST(Threading, RunOnThreadSyncAsync) {
58   Notification ThreadStarted, ThreadAdvanced, ThreadFinished;
59 
60   auto ThreadFunc = [&] {
61     ThreadStarted.notify();
62     ASSERT_TRUE(ThreadAdvanced.wait());
63     ThreadFinished.notify();
64   };
65 
66   llvm::thread Thread(ThreadFunc);
67   Thread.detach();
68   ASSERT_TRUE(ThreadStarted.wait());
69   ThreadAdvanced.notify();
70   ASSERT_TRUE(ThreadFinished.wait());
71 }
72 
73 TEST(Threading, RunOnThreadSync) {
74   std::atomic_bool Executed(false);
75   llvm::thread Thread(
76       [](void *Arg) { *static_cast<std::atomic_bool *>(Arg) = true; },
77       &Executed);
78   Thread.join();
79   ASSERT_EQ(Executed, true);
80 }
81 
82 #if defined(__APPLE__)
83 TEST(Threading, AppleStackSize) {
84   llvm::thread Thread([] {
85     volatile unsigned char Var[8 * 1024 * 1024 - 1024];
86     Var[0] = 0xff;
87     ASSERT_EQ(Var[0], 0xff);
88   });
89   Thread.join();
90 }
91 #endif
92 #endif
93 
94 } // end anon namespace
95