bytemap.h
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//===-- bytemap.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
//
//===----------------------------------------------------------------------===//
#ifndef SCUDO_BYTEMAP_H_
#define SCUDO_BYTEMAP_H_
#include "atomic_helpers.h"
#include "common.h"
#include "mutex.h"
namespace scudo {
template <uptr Size> class FlatByteMap {
public:
void initLinkerInitialized() {
Map = reinterpret_cast<u8 *>(map(nullptr, Size, "scudo:bytemap"));
}
void init() { initLinkerInitialized(); }
void unmapTestOnly() { unmap(reinterpret_cast<void *>(Map), Size); }
void set(uptr Index, u8 Value) {
DCHECK_LT(Index, Size);
DCHECK_EQ(0U, Map[Index]);
Map[Index] = Value;
}
u8 operator[](uptr Index) {
DCHECK_LT(Index, Size);
return Map[Index];
}
void disable() {}
void enable() {}
private:
u8 *Map;
};
template <uptr Level1Size, uptr Level2Size> class TwoLevelByteMap {
public:
void initLinkerInitialized() {
Level1Map = reinterpret_cast<atomic_uptr *>(
map(nullptr, sizeof(atomic_uptr) * Level1Size, "scudo:bytemap"));
}
void init() {
Mutex.init();
initLinkerInitialized();
}
void reset() {
for (uptr I = 0; I < Level1Size; I++) {
u8 *P = get(I);
if (!P)
continue;
unmap(P, Level2Size);
}
memset(Level1Map, 0, sizeof(atomic_uptr) * Level1Size);
}
void unmapTestOnly() {
reset();
unmap(reinterpret_cast<void *>(Level1Map),
sizeof(atomic_uptr) * Level1Size);
}
uptr size() const { return Level1Size * Level2Size; }
void set(uptr Index, u8 Value) {
DCHECK_LT(Index, Level1Size * Level2Size);
u8 *Level2Map = getOrCreate(Index / Level2Size);
DCHECK_EQ(0U, Level2Map[Index % Level2Size]);
Level2Map[Index % Level2Size] = Value;
}
u8 operator[](uptr Index) const {
DCHECK_LT(Index, Level1Size * Level2Size);
u8 *Level2Map = get(Index / Level2Size);
if (!Level2Map)
return 0;
return Level2Map[Index % Level2Size];
}
void disable() { Mutex.lock(); }
void enable() { Mutex.unlock(); }
private:
u8 *get(uptr Index) const {
DCHECK_LT(Index, Level1Size);
return reinterpret_cast<u8 *>(
atomic_load(&Level1Map[Index], memory_order_acquire));
}
u8 *getOrCreate(uptr Index) {
u8 *Res = get(Index);
if (!Res) {
ScopedLock L(Mutex);
if (!(Res = get(Index))) {
Res = reinterpret_cast<u8 *>(map(nullptr, Level2Size, "scudo:bytemap"));
atomic_store(&Level1Map[Index], reinterpret_cast<uptr>(Res),
memory_order_release);
}
}
return Res;
}
atomic_uptr *Level1Map;
HybridMutex Mutex;
};
} // namespace scudo
#endif // SCUDO_BYTEMAP_H_