llvm/libc/src/__support/OSUtil/linux/vdso.cpp

//===------------- Linux VDSO Implementation --------------------*- C++ -*-===//
//
// 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
//
//===----------------------------------------------------------------------===//
#include "src/__support/OSUtil/linux/vdso.h"
#include "hdr/link_macros.h"
#include "hdr/sys_auxv_macros.h"
#include "src/__support/CPP/array.h"
#include "src/__support/CPP/optional.h"
#include "src/__support/CPP/string_view.h"
#include "src/__support/threads/callonce.h"
#include "src/__support/threads/linux/futex_word.h"
#include "src/errno/libc_errno.h"
#include "src/sys/auxv/getauxval.h"
#include <linux/auxvec.h>

// TODO: This is a temporary workaround to avoid including elf.h
// Include our own headers for ElfW and friends once we have them.
namespace LIBC_NAMESPACE_DECL {

namespace vdso {

Symbol::VDSOArray Symbol::global_cache{ … };
CallOnceFlag Symbol::once_flag = …;

namespace {
// See https://refspecs.linuxfoundation.org/LSB_1.3.0/gLSB/gLSB/symverdefs.html
struct Verdaux { … };
struct Verdef { … };

// version search procedure specified by
// https://refspecs.linuxfoundation.org/LSB_1.3.0/gLSB/gLSB/symversion.html#SYMVERTBL
cpp::string_view find_version(Verdef *verdef, ElfW(Half) * versym,
                              const char *strtab, size_t idx) { … }

size_t shdr_get_symbol_count(ElfW(Shdr) * vdso_shdr, size_t e_shnum) { … }

struct VDSOSymbolTable { … };

struct PhdrInfo { … };
} // namespace

void Symbol::initialize_vdso_global_cache() { … }
} // namespace vdso
} // namespace LIBC_NAMESPACE_DECL