1*3cab2bb3Spatrick //===-- stack_trace_compressor.h --------------------------------*- C++ -*-===// 2*3cab2bb3Spatrick // 3*3cab2bb3Spatrick // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4*3cab2bb3Spatrick // See https://llvm.org/LICENSE.txt for license information. 5*3cab2bb3Spatrick // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6*3cab2bb3Spatrick // 7*3cab2bb3Spatrick //===----------------------------------------------------------------------===// 8*3cab2bb3Spatrick 9*3cab2bb3Spatrick #ifndef GWP_ASAN_STACK_TRACE_COMPRESSOR_ 10*3cab2bb3Spatrick #define GWP_ASAN_STACK_TRACE_COMPRESSOR_ 11*3cab2bb3Spatrick 12*3cab2bb3Spatrick #include <stddef.h> 13*3cab2bb3Spatrick #include <stdint.h> 14*3cab2bb3Spatrick 15*3cab2bb3Spatrick // These functions implement stack frame compression and decompression. We store 16*3cab2bb3Spatrick // the zig-zag encoded pointer difference between frame[i] and frame[i - 1] as 17*3cab2bb3Spatrick // a variable-length integer. This can reduce the memory overhead of stack 18*3cab2bb3Spatrick // traces by 50%. 19*3cab2bb3Spatrick 20*3cab2bb3Spatrick namespace gwp_asan { 21*3cab2bb3Spatrick namespace compression { 22*3cab2bb3Spatrick 23*3cab2bb3Spatrick // For the stack trace in `Unpacked` with length `UnpackedSize`, pack it into 24*3cab2bb3Spatrick // the buffer `Packed` maximum length `PackedMaxSize`. The return value is the 25*3cab2bb3Spatrick // number of bytes that were written to the output buffer. 26*3cab2bb3Spatrick size_t pack(const uintptr_t *Unpacked, size_t UnpackedSize, uint8_t *Packed, 27*3cab2bb3Spatrick size_t PackedMaxSize); 28*3cab2bb3Spatrick 29*3cab2bb3Spatrick // From the packed stack trace in `Packed` of length `PackedSize`, write the 30*3cab2bb3Spatrick // unpacked stack trace of maximum length `UnpackedMaxSize` into `Unpacked`. 31*3cab2bb3Spatrick // Returns the number of full entries unpacked, or zero on error. 32*3cab2bb3Spatrick size_t unpack(const uint8_t *Packed, size_t PackedSize, uintptr_t *Unpacked, 33*3cab2bb3Spatrick size_t UnpackedMaxSize); 34*3cab2bb3Spatrick 35*3cab2bb3Spatrick } // namespace compression 36*3cab2bb3Spatrick } // namespace gwp_asan 37*3cab2bb3Spatrick 38*3cab2bb3Spatrick #endif // GWP_ASAN_STACK_TRACE_COMPRESSOR_ 39