1//===-- stack_trace_compressor.h --------------------------------*- C++ -*-===// 2// 3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4// See https://llvm.org/LICENSE.txt for license information. 5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6// 7//===----------------------------------------------------------------------===// 8 9#ifndef GWP_ASAN_STACK_TRACE_COMPRESSOR_ 10#define GWP_ASAN_STACK_TRACE_COMPRESSOR_ 11 12#include <stddef.h> 13#include <stdint.h> 14 15// These functions implement stack frame compression and decompression. We store 16// the zig-zag encoded pointer difference between frame[i] and frame[i - 1] as 17// a variable-length integer. This can reduce the memory overhead of stack 18// traces by 50%. 19 20namespace gwp_asan { 21namespace compression { 22 23// For the stack trace in `Unpacked` with length `UnpackedSize`, pack it into 24// the buffer `Packed` maximum length `PackedMaxSize`. The return value is the 25// number of bytes that were written to the output buffer. 26size_t pack(const uintptr_t *Unpacked, size_t UnpackedSize, uint8_t *Packed, 27 size_t PackedMaxSize); 28 29// From the packed stack trace in `Packed` of length `PackedSize`, write the 30// unpacked stack trace of maximum length `UnpackedMaxSize` into `Unpacked`. 31// Returns the number of full entries unpacked, or zero on error. 32size_t unpack(const uint8_t *Packed, size_t PackedSize, uintptr_t *Unpacked, 33 size_t UnpackedMaxSize); 34 35} // namespace compression 36} // namespace gwp_asan 37 38#endif // GWP_ASAN_STACK_TRACE_COMPRESSOR_ 39