libsanitizer/sanitizer_common/sanitizer_mutex.h

   1 //===-- sanitizer_mutex.h ---------------------------------------*- C++ -*-===//
   2 //
   3 // This file is distributed under the University of Illinois Open Source
   4 // License. See LICENSE.TXT for details.
   5 //
   6 //===----------------------------------------------------------------------===//
   7 //
   8 // This file is a part of ThreadSanitizer/AddressSanitizer runtime.
   9 //
  10 //===----------------------------------------------------------------------===//
  11
  12 #ifndef SANITIZER_MUTEX_H
  13 #define SANITIZER_MUTEX_H
  14
  15 #include "sanitizer_atomic.h"
  16 #include "sanitizer_internal_defs.h"
  17 #include "sanitizer_libc.h"
  18
  19 namespace __sanitizer {
  20
  21 class StaticSpinMutex {
  22  public:
  23   void Init() {
  24     atomic_store(&state_, 0, memory_order_relaxed);
  25   }
  26
  27   void Lock() {
  28     if (TryLock())
  29       return;
  30     LockSlow();
  31   }
  32
  33   bool TryLock() {
  34     return atomic_exchange(&state_, 1, memory_order_acquire) == 0;
  35   }
  36
  37   void Unlock() {
  38     atomic_store(&state_, 0, memory_order_release);
  39   }
  40
  41   void CheckLocked() {
  42     CHECK_EQ(atomic_load(&state_, memory_order_relaxed), 1);
  43   }
  44
  45  private:
  46   atomic_uint8_t state_;
  47
  48   void NOINLINE LockSlow() {
  49     for (int i = 0;; i++) {
  50       if (i < 10)
  51         proc_yield(10);
  52       else
  53         internal_sched_yield();
  54       if (atomic_load(&state_, memory_order_relaxed) == 0
  55           && atomic_exchange(&state_, 1, memory_order_acquire) == 0)
  56         return;
  57     }
  58   }
  59 };
  60
  61 class SpinMutex : public StaticSpinMutex {
  62  public:
  63   SpinMutex() {
  64     Init();
  65   }
  66
  67  private:
  68   SpinMutex(const SpinMutex&);
  69   void operator=(const SpinMutex&);
  70 };
  71
  72 class BlockingMutex {
  73  public:
  74   explicit BlockingMutex(LinkerInitialized);
  75   BlockingMutex();
  76   void Lock();
  77   void Unlock();
  78   void CheckLocked();
  79  private:
  80   uptr opaque_storage_[10];
  81   uptr owner_;  // for debugging
  82 };
  83
  84 // Reader-writer spin mutex.
  85 class RWMutex {
  86  public:
  87   RWMutex() {
  88     atomic_store(&state_, kUnlocked, memory_order_relaxed);
  89   }
  90
  91   ~RWMutex() {
  92     CHECK_EQ(atomic_load(&state_, memory_order_relaxed), kUnlocked);
  93   }
  94
  95   void Lock() {
  96     u32 cmp = kUnlocked;
  97     if (atomic_compare_exchange_strong(&state_, &cmp, kWriteLock,
  98                                        memory_order_acquire))
  99       return;
 100     LockSlow();
 101   }
 102
 103   void Unlock() {
 104     u32 prev = atomic_fetch_sub(&state_, kWriteLock, memory_order_release);
 105     DCHECK_NE(prev & kWriteLock, 0);
 106     (void)prev;
 107   }
 108
 109   void ReadLock() {
 110     u32 prev = atomic_fetch_add(&state_, kReadLock, memory_order_acquire);
 111     if ((prev & kWriteLock) == 0)
 112       return;
 113     ReadLockSlow();
 114   }
 115
 116   void ReadUnlock() {
 117     u32 prev = atomic_fetch_sub(&state_, kReadLock, memory_order_release);
 118     DCHECK_EQ(prev & kWriteLock, 0);
 119     DCHECK_GT(prev & ~kWriteLock, 0);
 120     (void)prev;
 121   }
 122
 123   void CheckLocked() {
 124     CHECK_NE(atomic_load(&state_, memory_order_relaxed), kUnlocked);
 125   }
 126
 127  private:
 128   atomic_uint32_t state_;
 129
 130   enum {
 131     kUnlocked = 0,
 132     kWriteLock = 1,
 133     kReadLock = 2
 134   };
 135
 136   void NOINLINE LockSlow() {
 137     for (int i = 0;; i++) {
 138       if (i < 10)
 139         proc_yield(10);
 140       else
 141         internal_sched_yield();
 142       u32 cmp = atomic_load(&state_, memory_order_relaxed);
 143       if (cmp == kUnlocked &&
 144           atomic_compare_exchange_weak(&state_, &cmp, kWriteLock,
 145                                        memory_order_acquire))
 146           return;
 147     }
 148   }
 149
 150   void NOINLINE ReadLockSlow() {
 151     for (int i = 0;; i++) {
 152       if (i < 10)
 153         proc_yield(10);
 154       else
 155         internal_sched_yield();
 156       u32 prev = atomic_load(&state_, memory_order_acquire);
 157       if ((prev & kWriteLock) == 0)
 158         return;
 159     }
 160   }
 161
 162   RWMutex(const RWMutex&);
 163   void operator = (const RWMutex&);
 164 };
 165
 166 template<typename MutexType>
 167 class GenericScopedLock {
 168  public:
 169   explicit GenericScopedLock(MutexType *mu)
 170       : mu_(mu) {
 171     mu_->Lock();
 172   }
 173
 174   ~GenericScopedLock() {
 175     mu_->Unlock();
 176   }
 177
 178  private:
 179   MutexType *mu_;
 180
 181   GenericScopedLock(const GenericScopedLock&);
 182   void operator=(const GenericScopedLock&);
 183 };
 184
 185 template<typename MutexType>
 186 class GenericScopedReadLock {
 187  public:
 188   explicit GenericScopedReadLock(MutexType *mu)
 189       : mu_(mu) {
 190     mu_->ReadLock();
 191   }
 192
 193   ~GenericScopedReadLock() {
 194     mu_->ReadUnlock();
 195   }
 196
 197  private:
 198   MutexType *mu_;
 199
 200   GenericScopedReadLock(const GenericScopedReadLock&);
 201   void operator=(const GenericScopedReadLock&);
 202 };
 203
 204 typedef GenericScopedLock<StaticSpinMutex> SpinMutexLock;
 205 typedef GenericScopedLock<BlockingMutex> BlockingMutexLock;
 206 typedef GenericScopedLock<RWMutex> RWMutexLock;
 207 typedef GenericScopedReadLock<RWMutex> RWMutexReadLock;
 208
 209 }  // namespace __sanitizer
 210
 211 #endif  // SANITIZER_MUTEX_H