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| //===-- sanitizer_allocator_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
//
//===----------------------------------------------------------------------===//
//
// Part of the Sanitizer Allocator.
//
//===----------------------------------------------------------------------===//
#ifndef SANITIZER_ALLOCATOR_H
#error This file must be included inside sanitizer_allocator.h
#endif
// Maps integers in rage [0, kSize) to u8 values.
template <u64 kSize, typename AddressSpaceViewTy = LocalAddressSpaceView>
class FlatByteMap {
public:
using AddressSpaceView = AddressSpaceViewTy;
void Init() {
internal_memset(map_, 0, sizeof(map_));
}
void set(uptr idx, u8 val) {
CHECK_LT(idx, kSize);
CHECK_EQ(0U, map_[idx]);
map_[idx] = val;
}
u8 operator[] (uptr idx) {
CHECK_LT(idx, kSize);
// FIXME: CHECK may be too expensive here.
return map_[idx];
}
private:
u8 map_[kSize];
};
// TwoLevelByteMap maps integers in range [0, kSize1*kSize2) to u8 values.
// It is implemented as a two-dimensional array: array of kSize1 pointers
// to kSize2-byte arrays. The secondary arrays are mmaped on demand.
// Each value is initially zero and can be set to something else only once.
// Setting and getting values from multiple threads is safe w/o extra locking.
template <u64 kSize1, u64 kSize2,
typename AddressSpaceViewTy = LocalAddressSpaceView,
class MapUnmapCallback = NoOpMapUnmapCallback>
class TwoLevelByteMap {
public:
using AddressSpaceView = AddressSpaceViewTy;
void Init() {
internal_memset(map1_, 0, sizeof(map1_));
mu_.Init();
}
void TestOnlyUnmap() {
for (uptr i = 0; i < kSize1; i++) {
u8 *p = Get(i);
if (!p) continue;
MapUnmapCallback().OnUnmap(reinterpret_cast<uptr>(p), kSize2);
UnmapOrDie(p, kSize2);
}
}
uptr size() const { return kSize1 * kSize2; }
uptr size1() const { return kSize1; }
uptr size2() const { return kSize2; }
void set(uptr idx, u8 val) {
CHECK_LT(idx, kSize1 * kSize2);
u8 *map2 = GetOrCreate(idx / kSize2);
CHECK_EQ(0U, map2[idx % kSize2]);
map2[idx % kSize2] = val;
}
u8 operator[] (uptr idx) const {
CHECK_LT(idx, kSize1 * kSize2);
u8 *map2 = Get(idx / kSize2);
if (!map2) return 0;
auto value_ptr = AddressSpaceView::Load(&map2[idx % kSize2]);
return *value_ptr;
}
private:
u8 *Get(uptr idx) const {
CHECK_LT(idx, kSize1);
return reinterpret_cast<u8 *>(
atomic_load(&map1_[idx], memory_order_acquire));
}
u8 *GetOrCreate(uptr idx) {
u8 *res = Get(idx);
if (!res) {
SpinMutexLock l(&mu_);
if (!(res = Get(idx))) {
res = (u8*)MmapOrDie(kSize2, "TwoLevelByteMap");
MapUnmapCallback().OnMap(reinterpret_cast<uptr>(res), kSize2);
atomic_store(&map1_[idx], reinterpret_cast<uptr>(res),
memory_order_release);
}
}
return res;
}
atomic_uintptr_t map1_[kSize1];
StaticSpinMutex mu_;
};
|