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// Copyright (c) 2011 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.
// Define the necessary code and global data to look for kDebugOnStart command
// line argument. When the command line argument is detected, it invokes the
// debugger, if no system-wide debugger is registered, a debug break is done.
#ifndef BASE_DEBUG_DEBUG_ON_START_WIN_H_
#define BASE_DEBUG_DEBUG_ON_START_WIN_H_
#include "base/basictypes.h"
#include "build/build_config.h"
// This only works on Windows. It's legal to include on other platforms, but
// will be a NOP.
#if defined(OS_WIN)
#ifndef DECLSPEC_SELECTANY
#define DECLSPEC_SELECTANY __declspec(selectany)
#endif
namespace base {
namespace debug {
// There is no way for this code, as currently implemented, to work across DLLs.
// TODO(rvargas): It looks like we really don't use this code, at least not for
// Chrome. Figure out if it's really worth implementing something simpler.
#if !defined(COMPONENT_BUILD)
// Debug on start functions and data.
class DebugOnStart {
public:
// Expected function type in the .CRT$XI* section.
// Note: See VC\crt\src\internal.h for reference.
typedef int (__cdecl *PIFV)(void);
// Looks at the command line for kDebugOnStart argument. If found, it invokes
// the debugger, if this fails, it crashes.
static int __cdecl Init();
// Returns true if the 'argument' is present in the 'command_line'. It does
// not use the CRT, only Kernel32 functions.
static bool FindArgument(wchar_t* command_line, const char* argument);
};
// Set the function pointer to our function to look for a crash on start. The
// XIB section is started pretty early in the program initialization so in
// theory it should be called before any user created global variable
// initialization code and CRT initialization code.
// Note: See VC\crt\src\defsects.inc and VC\crt\src\crt0.c for reference.
#ifdef _WIN64
// "Fix" the segment. On x64, the .CRT segment is merged into the .rdata segment
// so it contains const data only.
#pragma const_seg(push, ".CRT$XIB")
// Declare the pointer so the CRT will find it.
extern const DebugOnStart::PIFV debug_on_start;
DECLSPEC_SELECTANY const DebugOnStart::PIFV debug_on_start =
&DebugOnStart::Init;
// Fix back the segment.
#pragma const_seg(pop)
#else // _WIN64
// "Fix" the segment. On x86, the .CRT segment is merged into the .data segment
// so it contains non-const data only.
#pragma data_seg(push, ".CRT$XIB")
// Declare the pointer so the CRT will find it.
DECLSPEC_SELECTANY DebugOnStart::PIFV debug_on_start = &DebugOnStart::Init;
// Fix back the segment.
#pragma data_seg(pop)
#endif // _WIN64
#endif // defined(COMPONENT_BUILD)
} // namespace debug
} // namespace base
#endif // defined(OS_WIN)
#endif // BASE_DEBUG_DEBUG_ON_START_WIN_H_
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