blob: e0bc4e9c4a451110673bb0e383c16a6babbcb4aa [file] [log] [blame]
//===-- sanitizer_stack_store.h ---------------------------------*- C++ -*-===//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
#include "sanitizer_atomic.h"
#include "sanitizer_common.h"
#include "sanitizer_internal_defs.h"
#include "sanitizer_mutex.h"
#include "sanitizer_stacktrace.h"
namespace __sanitizer {
class StackStore {
static constexpr uptr kBlockSizeFrames = 0x100000;
static constexpr uptr kBlockCount = 0x1000;
static constexpr uptr kBlockSizeBytes = kBlockSizeFrames * sizeof(uptr);
enum class Compression : u8 {
None = 0,
constexpr StackStore() = default;
using Id = u32; // Enough for 2^32 * sizeof(uptr) bytes of traces.
static_assert(u64(kBlockCount) * kBlockSizeFrames == 1ull << (sizeof(Id) * 8),
Id Store(const StackTrace &trace,
uptr *pack /* number of blocks completed by this call */);
StackTrace Load(Id id);
uptr Allocated() const;
// Packs all blocks which don't expect any more writes. A block is going to be
// packed once. As soon trace from that block was requested, it will unpack
// and stay unpacked after that.
// Returns the number of released bytes.
uptr Pack(Compression type);
void TestOnlyUnmap();
friend class StackStoreTest;
static constexpr uptr GetBlockIdx(uptr frame_idx) {
return frame_idx / kBlockSizeFrames;
static constexpr uptr GetInBlockIdx(uptr frame_idx) {
return frame_idx % kBlockSizeFrames;
static constexpr uptr IdToOffset(Id id) {
CHECK_NE(id, 0);
return id - 1; // Avoid zero as id.
static constexpr uptr OffsetToId(Id id) {
// This makes UINT32_MAX to 0 and it will be retrived as and empty stack.
// But this is not a problem as we will not be able to store anything after
// that anyway.
return id + 1; // Avoid zero as id.
uptr *Alloc(uptr count, uptr *idx, uptr *pack);
// Total number of allocated frames.
atomic_uintptr_t total_frames_ = {};
// Each block will hold pointer to exactly kBlockSizeFrames.
class BlockInfo {
atomic_uintptr_t data_;
// Counter to track store progress to know when we can Pack() the block.
atomic_uint32_t stored_;
// Protects alloc of new blocks.
mutable StaticSpinMutex mtx_;
enum class State : u8 {
Storing = 0,
State state GUARDED_BY(mtx_);
uptr *Create();
uptr *Get() const;
uptr *GetOrCreate();
uptr *GetOrUnpack();
uptr Pack(Compression type);
uptr Allocated() const;
void TestOnlyUnmap();
bool Stored(uptr n);
bool IsPacked() const;
BlockInfo blocks_[kBlockCount] = {};
} // namespace __sanitizer