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//===-- tsan_mutexset.h -----------------------------------------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file is a part of ThreadSanitizer (TSan), a race detector.
//
// MutexSet holds the set of mutexes currently held by a thread.
//===----------------------------------------------------------------------===//
#ifndef TSAN_MUTEXSET_H
#define TSAN_MUTEXSET_H
#include "tsan_defs.h"
namespace __tsan {
class MutexSet {
public:
// Holds limited number of mutexes.
// The oldest mutexes are discarded on overflow.
static constexpr uptr kMaxSize = 16;
struct Desc {
uptr addr;
StackID stack_id;
u64 id;
u64 epoch;
u32 seq;
u32 count;
bool write;
Desc() { internal_memset(this, 0, sizeof(*this)); }
Desc(const Desc& other) { *this = other; }
Desc& operator=(const MutexSet::Desc& other) {
internal_memcpy(this, &other, sizeof(*this));
return *this;
}
};
MutexSet();
// The 'id' is obtained from SyncVar::GetId().
void Add(u64 id, bool write, u64 epoch);
void Del(u64 id, bool write);
void Remove(u64 id); // Removes the mutex completely (if it's destroyed).
void AddAddr(uptr addr, StackID stack_id, bool write);
void DelAddr(uptr addr, bool destroy = false);
uptr Size() const;
Desc Get(uptr i) const;
private:
#if !SANITIZER_GO
u32 seq_ = 0;
uptr size_ = 0;
Desc descs_[kMaxSize];
void RemovePos(uptr i);
#endif
};
// MutexSet is too large to live on stack.
// DynamicMutexSet can be use used to create local MutexSet's.
class DynamicMutexSet {
public:
DynamicMutexSet();
~DynamicMutexSet();
MutexSet* operator->() { return ptr_; }
operator MutexSet*() { return ptr_; }
DynamicMutexSet(const DynamicMutexSet&) = delete;
DynamicMutexSet& operator=(const DynamicMutexSet&) = delete;
private:
MutexSet* ptr_;
#if SANITIZER_GO
MutexSet set_;
#endif
};
// Go does not have mutexes, so do not spend memory and time.
// (Go sync.Mutex is actually a semaphore -- can be unlocked
// in different goroutine).
#if SANITIZER_GO
MutexSet::MutexSet() {}
void MutexSet::Add(u64 id, bool write, u64 epoch) {}
void MutexSet::Del(u64 id, bool write) {}
void MutexSet::Remove(u64 id) {}
void MutexSet::AddAddr(uptr addr, StackID stack_id, bool write) {}
void MutexSet::DelAddr(uptr addr, bool destroy) {}
uptr MutexSet::Size() const { return 0; }
MutexSet::Desc MutexSet::Get(uptr i) const { return Desc(); }
DynamicMutexSet::DynamicMutexSet() : ptr_(&set_) {}
DynamicMutexSet::~DynamicMutexSet() {}
#endif
} // namespace __tsan
#endif // TSAN_MUTEXSET_H