// Copyright 2019 The Chromium Authors // Use of this source code is governed by a BSD-style license that can be // found in the LICENSE file. #ifndef COMPONENTS_GWP_ASAN_COMMON_PACK_STACK_TRACE_H_ #define COMPONENTS_GWP_ASAN_COMMON_PACK_STACK_TRACE_H_ #include <stddef.h> #include <stdint.h> // These routines 'compress' a stack trace by storing a stack trace as a // starting address, followed by offsets from the previous pointer. All values // are stored using variable-length integers to reduce space. Furthermore, they // are zigzag encoded, like in protobuf encoding, to store negative offsets // efficiently. On 64-bit platforms this packing can reduce space required to // store a stack trace by over 50%. namespace gwp_asan { namespace internal { // From the stack trace in |unpacked| of length |unpacked_size|, pack it into // the buffer |packed| with maximum length |packed_max_size|. The return value // is the number of bytes that were written to the output buffer. size_t Pack(const uintptr_t* unpacked, size_t unpacked_size, uint8_t* packed, size_t packed_max_size); // From the packed stack trace in |packed| of length |packed_size|, write the // unpacked stack trace of maximum length |unpacked_max_size| into |unpacked|. // Returns the number of entries un packed, or 0 on error. size_t Unpack(const uint8_t* packed, size_t packed_size, uintptr_t* unpacked, size_t unpacked_max_size); } // namespace internal } // namespace gwp_asan #endif // COMPONENTS_GWP_ASAN_COMMON_PACK_STACK_TRACE_H_