blob: 2ec2ab28b51b7c9d3e254b0d02218dfb901a4192 [file] [log] [blame]
// Copyright 2017 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include <stdint.h>
#include "build/build_config.h"
#include "chrome/installer/mini_installer/mini_installer.h"
extern "C" IMAGE_DOS_HEADER __ImageBase;
extern "C" int __stdcall MainEntryPoint() {
mini_installer::ProcessExitResult result =
// Executables instrumented with ASAN need CRT functions. We do not use
// the /ENTRY switch for ASAN instrumented executable and a "main" function
// is required.
extern "C" int WINAPI wWinMain(HINSTANCE /* instance */,
HINSTANCE /* previous_instance */,
LPWSTR /* command_line */,
int /* command_show */) {
return MainEntryPoint();
// We don't link with the CRT (this is enforced through use of the /ENTRY linker
// flag) so we have to implement CRT functions that the compiler generates calls
// to.
// VC Express editions don't come with the memset CRT obj file and linking to
// the obj files between versions becomes a bit problematic. Therefore,
// simply implement memset.
// This also avoids having to explicitly set the __sse2_available hack when
// linking with both the x64 and x86 obj files which is required when not
// linking with the std C lib in certain instances (including Chromium) with
// MSVC. __sse2_available determines whether to use SSE2 intructions with
// std C lib routines, and is set by MSVC's std C lib implementation normally.
extern "C" {
#ifdef __clang__
// Marking memset as used is necessary in order to link with LLVM link-time
// optimization (LTO). It prevents LTO from discarding the memset symbol,
// allowing for compiler-generated references to memset to be satisfied.
// MSVC only allows declaring an intrinsic function if it's marked
// as `pragma function` first. `pragma function` also means that calls
// to memset must not use the intrinsic; we don't care abou this second
// (and main) meaning of the pragma.
// clang-cl doesn't implement this pragma at all, so don't use it there.
#pragma function(memset)
void* memset(void* dest, int c, size_t count) {
uint8_t* scan = reinterpret_cast<uint8_t*>(dest);
while (count--)
*scan++ = static_cast<uint8_t>(c);
return dest;
#if defined(_DEBUG) && defined(ARCH_CPU_ARM64)
// The compiler generates calls to memcpy for ARM64 debug builds so we need to
// supply a memcpy implementation in that configuration.
// See comments above for why we do this incantation.
#ifdef __clang__
#pragma function(memcpy)
void* memcpy(void* destination, const void* source, size_t count) {
auto* dst = reinterpret_cast<uint8_t*>(destination);
auto* src = reinterpret_cast<const uint8_t*>(source);
while (count--)
*dst++ = *src++;
return destination;
} // extern "C"