1 // Copyright (c) 2011 The Chromium Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 // Define the necessary code and global data to look for kDebugOnStart command 6 // line argument. When the command line argument is detected, it invokes the 7 // debugger, if no system-wide debugger is registered, a debug break is done. 8 9 #ifndef BASE_DEBUG_DEBUG_ON_START_WIN_H_ 10 #define BASE_DEBUG_DEBUG_ON_START_WIN_H_ 11 12 #include "base/basictypes.h" 13 #include "build/build_config.h" 14 15 // This only works on Windows. It's legal to include on other platforms, but 16 // will be a NOP. 17 #if defined(OS_WIN) 18 19 #ifndef DECLSPEC_SELECTANY 20 #define DECLSPEC_SELECTANY __declspec(selectany) 21 #endif 22 23 namespace base { 24 namespace debug { 25 26 // There is no way for this code, as currently implemented, to work across DLLs. 27 // TODO(rvargas): It looks like we really don't use this code, at least not for 28 // Chrome. Figure out if it's really worth implementing something simpler. 29 #if !defined(COMPONENT_BUILD) 30 31 // Debug on start functions and data. 32 class DebugOnStart { 33 public: 34 // Expected function type in the .CRT$XI* section. 35 // Note: See VC\crt\src\internal.h for reference. 36 typedef int (__cdecl *PIFV)(void); 37 38 // Looks at the command line for kDebugOnStart argument. If found, it invokes 39 // the debugger, if this fails, it crashes. 40 static int __cdecl Init(); 41 42 // Returns true if the 'argument' is present in the 'command_line'. It does 43 // not use the CRT, only Kernel32 functions. 44 static bool FindArgument(wchar_t* command_line, const char* argument); 45 }; 46 47 // Set the function pointer to our function to look for a crash on start. The 48 // XIB section is started pretty early in the program initialization so in 49 // theory it should be called before any user created global variable 50 // initialization code and CRT initialization code. 51 // Note: See VC\crt\src\defsects.inc and VC\crt\src\crt0.c for reference. 52 #ifdef _WIN64 53 54 // "Fix" the segment. On x64, the .CRT segment is merged into the .rdata segment 55 // so it contains const data only. 56 #pragma const_seg(push, ".CRT$XIB") 57 // Declare the pointer so the CRT will find it. 58 extern const DebugOnStart::PIFV debug_on_start; 59 DECLSPEC_SELECTANY const DebugOnStart::PIFV debug_on_start = 60 &DebugOnStart::Init; 61 // Fix back the segment. 62 #pragma const_seg(pop) 63 64 #else // _WIN64 65 66 // "Fix" the segment. On x86, the .CRT segment is merged into the .data segment 67 // so it contains non-const data only. 68 #pragma data_seg(push, ".CRT$XIB") 69 // Declare the pointer so the CRT will find it. 70 DECLSPEC_SELECTANY DebugOnStart::PIFV debug_on_start = &DebugOnStart::Init; 71 // Fix back the segment. 72 #pragma data_seg(pop) 73 74 #endif // _WIN64 75 76 #endif // defined(COMPONENT_BUILD) 77 78 } // namespace debug 79 } // namespace base 80 81 #endif // defined(OS_WIN) 82 83 #endif // BASE_DEBUG_DEBUG_ON_START_WIN_H_ 84
