forked from OSchip/llvm-project
68 lines
3.4 KiB
C++
68 lines
3.4 KiB
C++
//===-- sanitizer_coverage_win_sections.cpp -------------------------------===//
|
|
//
|
|
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
|
|
// See https://llvm.org/LICENSE.txt for license information.
|
|
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
//
|
|
// This file defines delimiters for Sanitizer Coverage's section. It contains
|
|
// Windows specific tricks to coax the linker into giving us the start and stop
|
|
// addresses of a section, as ELF linkers can do, to get the size of certain
|
|
// arrays. According to https://msdn.microsoft.com/en-us/library/7977wcck.aspx
|
|
// sections with the same name before "$" are sorted alphabetically by the
|
|
// string that comes after "$" and merged into one section. We take advantage
|
|
// of this by putting data we want the size of into the middle (M) of a section,
|
|
// by using the letter "M" after "$". We get the start of this data (ie:
|
|
// __start_section_name) by making the start variable come at the start of the
|
|
// section (using the letter A after "$"). We do the same to get the end of the
|
|
// data by using the letter "Z" after "$" to make the end variable come after
|
|
// the data. Note that because of our technique the address of the start
|
|
// variable is actually the address of data that comes before our middle
|
|
// section. We also need to prevent the linker from adding any padding. Each
|
|
// technique we use for this is explained in the comments below.
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
#include "sanitizer_platform.h"
|
|
#if SANITIZER_WINDOWS
|
|
#include <stdint.h>
|
|
|
|
extern "C" {
|
|
// Use uint64_t so the linker won't need to add any padding if it tries to word
|
|
// align the start of the 8-bit counters array. The array will always start 8
|
|
// bytes after __start_sancov_cntrs.
|
|
#pragma section(".SCOV$CA", read, write)
|
|
__declspec(allocate(".SCOV$CA")) uint64_t __start___sancov_cntrs = 0;
|
|
|
|
// Even though we said not to align __stop__sancov_cntrs (using the "align"
|
|
// declspec), MSVC's linker may try to align the section, .SCOV$CZ, containing
|
|
// it. This can cause a mismatch between the number of PCs and counters since
|
|
// each PCTable element is 8 bytes (unlike counters which are 1 byte) so no
|
|
// padding would be added to align .SCOVP$Z, However, if .SCOV$CZ section is 1
|
|
// byte, the linker won't try to align it on an 8-byte boundary, so use a
|
|
// uint8_t for __stop_sancov_cntrs.
|
|
#pragma section(".SCOV$CZ", read, write)
|
|
__declspec(allocate(".SCOV$CZ")) __declspec(align(1)) uint8_t
|
|
__stop___sancov_cntrs = 0;
|
|
|
|
#pragma section(".SCOV$GA", read, write)
|
|
__declspec(allocate(".SCOV$GA")) uint64_t __start___sancov_guards = 0;
|
|
#pragma section(".SCOV$GZ", read, write)
|
|
__declspec(allocate(".SCOV$GZ")) __declspec(align(1)) uint8_t
|
|
__stop___sancov_guards = 0;
|
|
|
|
// The guard array and counter array should both be merged into the .data
|
|
// section to reduce the number of PE sections. However, because PCTable is
|
|
// constant it should be merged with the .rdata section.
|
|
#pragma comment(linker, "/MERGE:.SCOV=.data")
|
|
|
|
#pragma section(".SCOVP$A", read)
|
|
__declspec(allocate(".SCOVP$A")) uint64_t __start___sancov_pcs = 0;
|
|
#pragma section(".SCOVP$Z", read)
|
|
__declspec(allocate(".SCOVP$Z")) __declspec(align(1)) uint8_t
|
|
__stop___sancov_pcs = 0;
|
|
|
|
#pragma comment(linker, "/MERGE:.SCOVP=.rdata")
|
|
}
|
|
#endif // SANITIZER_WINDOWS
|