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108 lines
3.1 KiB
C++
108 lines
3.1 KiB
C++
//===-- sanitizer_allocator_bytemap.h ---------------------------*- C++ -*-===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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// Part of the Sanitizer Allocator.
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//
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//===----------------------------------------------------------------------===//
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#ifndef SANITIZER_ALLOCATOR_H
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#error This file must be included inside sanitizer_allocator.h
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#endif
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// Maps integers in rage [0, kSize) to u8 values.
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template <u64 kSize, typename AddressSpaceViewTy = LocalAddressSpaceView>
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class FlatByteMap {
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public:
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using AddressSpaceView = AddressSpaceViewTy;
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void Init() {
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internal_memset(map_, 0, sizeof(map_));
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}
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void set(uptr idx, u8 val) {
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CHECK_LT(idx, kSize);
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CHECK_EQ(0U, map_[idx]);
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map_[idx] = val;
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}
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u8 operator[] (uptr idx) {
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CHECK_LT(idx, kSize);
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// FIXME: CHECK may be too expensive here.
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return map_[idx];
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}
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private:
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u8 map_[kSize];
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};
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// TwoLevelByteMap maps integers in range [0, kSize1*kSize2) to u8 values.
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// It is implemented as a two-dimensional array: array of kSize1 pointers
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// to kSize2-byte arrays. The secondary arrays are mmaped on demand.
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// Each value is initially zero and can be set to something else only once.
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// Setting and getting values from multiple threads is safe w/o extra locking.
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template <u64 kSize1, u64 kSize2,
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typename AddressSpaceViewTy = LocalAddressSpaceView,
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class MapUnmapCallback = NoOpMapUnmapCallback>
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class TwoLevelByteMap {
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public:
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using AddressSpaceView = AddressSpaceViewTy;
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void Init() {
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internal_memset(map1_, 0, sizeof(map1_));
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mu_.Init();
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}
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void TestOnlyUnmap() {
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for (uptr i = 0; i < kSize1; i++) {
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u8 *p = Get(i);
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if (!p) continue;
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MapUnmapCallback().OnUnmap(reinterpret_cast<uptr>(p), kSize2);
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UnmapOrDie(p, kSize2);
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}
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}
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uptr size() const { return kSize1 * kSize2; }
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uptr size1() const { return kSize1; }
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uptr size2() const { return kSize2; }
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void set(uptr idx, u8 val) {
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CHECK_LT(idx, kSize1 * kSize2);
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u8 *map2 = GetOrCreate(idx / kSize2);
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CHECK_EQ(0U, map2[idx % kSize2]);
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map2[idx % kSize2] = val;
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}
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u8 operator[] (uptr idx) const {
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CHECK_LT(idx, kSize1 * kSize2);
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u8 *map2 = Get(idx / kSize2);
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if (!map2) return 0;
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auto value_ptr = AddressSpaceView::Load(&map2[idx % kSize2]);
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return *value_ptr;
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}
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private:
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u8 *Get(uptr idx) const {
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CHECK_LT(idx, kSize1);
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return reinterpret_cast<u8 *>(
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atomic_load(&map1_[idx], memory_order_acquire));
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}
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u8 *GetOrCreate(uptr idx) {
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u8 *res = Get(idx);
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if (!res) {
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SpinMutexLock l(&mu_);
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if (!(res = Get(idx))) {
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res = (u8*)MmapOrDie(kSize2, "TwoLevelByteMap");
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MapUnmapCallback().OnMap(reinterpret_cast<uptr>(res), kSize2);
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atomic_store(&map1_[idx], reinterpret_cast<uptr>(res),
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memory_order_release);
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}
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}
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return res;
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}
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atomic_uintptr_t map1_[kSize1];
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StaticSpinMutex mu_;
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};
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