tsan_defs.h

//===-- tsan_defs.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.
//
//===----------------------------------------------------------------------===//

#ifndef TSAN_DEFS_H
#define TSAN_DEFS_H

#include "sanitizer_common/sanitizer_internal_defs.h"
#include "sanitizer_common/sanitizer_libc.h"
#include "tsan_stat.h"
#include "ubsan/ubsan_platform.h"

// Setup defaults for compile definitions.
#ifndef TSAN_NO_HISTORY
# define TSAN_NO_HISTORY 0
#endif

#ifndef TSAN_COLLECT_STATS
# define TSAN_COLLECT_STATS 0
#endif

#ifndef TSAN_CONTAINS_UBSAN
# if CAN_SANITIZE_UB && !SANITIZER_GO
#  define TSAN_CONTAINS_UBSAN 1
# else
#  define TSAN_CONTAINS_UBSAN 0
# endif
#endif

namespace __tsan {

const int kClkBits = 42;
const unsigned kMaxTidReuse = (1 << (64 - kClkBits)) - 1;

struct ClockElem {
  u64 epoch  : kClkBits;
  u64 reused : 64 - kClkBits;  // tid reuse count
};

struct ClockBlock {
  static const uptr kSize = 512;
  static const uptr kTableSize = kSize / sizeof(u32);
  static const uptr kClockCount = kSize / sizeof(ClockElem);
  static const uptr kRefIdx = kTableSize - 1;
  static const uptr kBlockIdx = kTableSize - 2;

  union {
    u32       table[kTableSize];
    ClockElem clock[kClockCount];
  };

  ClockBlock() {
  }
};

const int kTidBits = 13;
// Reduce kMaxTid by kClockCount because one slot in ClockBlock table is
// occupied by reference counter, so total number of elements we can store
// in SyncClock is kClockCount * (kTableSize - 1).
const unsigned kMaxTid = (1 << kTidBits) - ClockBlock::kClockCount;
#if !SANITIZER_GO
const unsigned kMaxTidInClock = kMaxTid * 2;  // This includes msb 'freed' bit.
#else
const unsigned kMaxTidInClock = kMaxTid;  // Go does not track freed memory.
#endif
const uptr kShadowStackSize = 64 * 1024;

// Count of shadow values in a shadow cell.
const uptr kShadowCnt = 4;

// That many user bytes are mapped onto a single shadow cell.
const uptr kShadowCell = 8;

// Size of a single shadow value (u64).
const uptr kShadowSize = 8;

// Shadow memory is kShadowMultiplier times larger than user memory.
const uptr kShadowMultiplier = kShadowSize * kShadowCnt / kShadowCell;

// That many user bytes are mapped onto a single meta shadow cell.
// Must be less or equal to minimal memory allocator alignment.
const uptr kMetaShadowCell = 8;

// Size of a single meta shadow value (u32).
const uptr kMetaShadowSize = 4;

#if TSAN_NO_HISTORY
const bool kCollectHistory = false;
#else
const bool kCollectHistory = true;
#endif

const u16 kInvalidTid = kMaxTid + 1;

// The following "build consistency" machinery ensures that all source files
// are built in the same configuration. Inconsistent builds lead to
// hard to debug crashes.
#if SANITIZER_DEBUG
void build_consistency_debug();
#else
void build_consistency_release();
#endif

#if TSAN_COLLECT_STATS
void build_consistency_stats();
#else
void build_consistency_nostats();
#endif

static inline void USED build_consistency() {
#if SANITIZER_DEBUG
  build_consistency_debug();
#else
  build_consistency_release();
#endif
#if TSAN_COLLECT_STATS
  build_consistency_stats();
#else
  build_consistency_nostats();
#endif
}

template<typename T>
T min(T a, T b) {
  return a < b ? a : b;
}

template<typename T>
T max(T a, T b) {
  return a > b ? a : b;
}

template<typename T>
T RoundUp(T p, u64 align) {
  DCHECK_EQ(align & (align - 1), 0);
  return (T)(((u64)p + align - 1) & ~(align - 1));
}

template<typename T>
T RoundDown(T p, u64 align) {
  DCHECK_EQ(align & (align - 1), 0);
  return (T)((u64)p & ~(align - 1));
}

// Zeroizes high part, returns 'bits' lsb bits.
template<typename T>
T GetLsb(T v, int bits) {
  return (T)((u64)v & ((1ull << bits) - 1));
}

struct MD5Hash {
  u64 hash[2];
  bool operator==(const MD5Hash &other) const;
};

MD5Hash md5_hash(const void *data, uptr size);

struct Processor;
struct ThreadState;
class ThreadContext;
struct Context;
struct ReportStack;
class ReportDesc;
class RegionAlloc;

// Descriptor of user's memory block.
struct MBlock {
  u64  siz : 48;
  u64  tag : 16;
  u32  stk;
  u16  tid;
};

COMPILER_CHECK(sizeof(MBlock) == 16);

enum ExternalTag : uptr {
  kExternalTagNone = 0,
  kExternalTagSwiftModifyingAccess = 1,
  kExternalTagFirstUserAvailable = 2,
  kExternalTagMax = 1024,
  // Don't set kExternalTagMax over 65,536, since MBlock only stores tags
  // as 16-bit values, see tsan_defs.h.
};

}  // namespace __tsan

#endif  // TSAN_DEFS_H