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