Add m-esr52 at 52.6.0

1 files changed, 121 insertions, 0 deletions

diff --git a/xpcom/build/mach_override.h b/xpcom/build/mach_override.h
new file mode 100644
index 000000000..d9be988a3
--- /dev/null
+++ b/xpcom/build/mach_override.h
@@ -0,0 +1,121 @@
+/*******************************************************************************
+	mach_override.h
+		Copyright (c) 2003-2009 Jonathan 'Wolf' Rentzsch: <http://rentzsch.com>
+		Some rights reserved: <http://opensource.org/licenses/mit-license.php>
+
+	***************************************************************************/
+
+/***************************************************************************//**
+	@mainpage	mach_override
+	@author		Jonathan 'Wolf' Rentzsch: <http://rentzsch.com>
+	
+	This package, coded in C to the Mach API, allows you to override ("patch")
+	program- and system-supplied functions at runtime. You can fully replace
+	functions with your implementations, or merely head- or tail-patch the
+	original implementations.
+	
+	Use it by #include'ing mach_override.h from your .c, .m or .mm file(s).
+	
+	@todo	Discontinue use of Carbon's MakeDataExecutable() and
+			CompareAndSwap() calls and start using the Mach equivalents, if they
+			exist. If they don't, write them and roll them in. That way, this
+			code will be pure Mach, which will make it easier to use everywhere.
+			Update: MakeDataExecutable() has been replaced by
+			msync(MS_INVALIDATE). There is an OSCompareAndSwap in libkern, but
+			I'm currently unsure if I can link against it. May have to roll in
+			my own version...
+	@todo	Stop using an entire 4K high-allocated VM page per 28-byte escape
+			branch island. Done right, this will dramatically speed up escape
+			island allocations when they number over 250. Then again, if you're
+			overriding more than 250 functions, maybe speed isn't your main
+			concern...
+	@todo	Add detection of: b, bl, bla, bc, bcl, bcla, bcctrl, bclrl
+			first-instructions. Initially, we should refuse to override
+			functions beginning with these instructions. Eventually, we should
+			dynamically rewrite them to make them position-independent.
+	@todo	Write mach_unoverride(), which would remove an override placed on a
+			function. Must be multiple-override aware, which means an almost
+			complete rewrite under the covers, because the target address can't
+			be spread across two load instructions like it is now since it will
+			need to be atomically updatable.
+	@todo	Add non-rentry variants of overrides to test_mach_override.
+
+	***************************************************************************/
+
+#ifndef		_mach_override_
+#define		_mach_override_
+
+#include <sys/types.h>
+#include <mach/error.h>
+
+#ifdef	__cplusplus
+	extern	"C"	{
+#endif
+
+/**
+	Returned if the function to be overrided begins with a 'mfctr' instruction.
+*/
+#define	err_cannot_override	(err_local|1)
+
+/************************************************************************************//**
+	Dynamically overrides the function implementation referenced by
+	originalFunctionAddress with the implentation pointed to by overrideFunctionAddress.
+	Optionally returns a pointer to a "reentry island" which, if jumped to, will resume
+	the original implementation.
+	
+	@param	originalFunctionAddress			->	Required address of the function to
+												override (with overrideFunctionAddress).
+	@param	overrideFunctionAddress			->	Required address to the overriding
+												function.
+	@param	originalFunctionReentryIsland	<-	Optional pointer to pointer to the
+												reentry island. Can be nullptr.
+	@result									<-	err_cannot_override if the original
+												function's implementation begins with
+												the 'mfctr' instruction.
+
+	************************************************************************************/
+
+    mach_error_t
+mach_override_ptr(
+	void *originalFunctionAddress,
+    const void *overrideFunctionAddress,
+    void **originalFunctionReentryIsland );
+
+/************************************************************************************//**
+	
+
+	************************************************************************************/
+ 
+#ifdef	__cplusplus
+
+#define MACH_OVERRIDE( ORIGINAL_FUNCTION_RETURN_TYPE, ORIGINAL_FUNCTION_NAME, ORIGINAL_FUNCTION_ARGS, ERR )			\
+	{																												\
+		static ORIGINAL_FUNCTION_RETURN_TYPE (*ORIGINAL_FUNCTION_NAME##_reenter)ORIGINAL_FUNCTION_ARGS;				\
+		static bool ORIGINAL_FUNCTION_NAME##_overriden = false;														\
+		class mach_override_class__##ORIGINAL_FUNCTION_NAME {														\
+		public:																										\
+			static kern_return_t override(void *originalFunctionPtr) {												\
+				kern_return_t result = err_none;																	\
+				if (!ORIGINAL_FUNCTION_NAME##_overriden) {															\
+					ORIGINAL_FUNCTION_NAME##_overriden = true;														\
+					result = mach_override_ptr( (void*)originalFunctionPtr,											\
+												(void*)mach_override_class__##ORIGINAL_FUNCTION_NAME::replacement,	\
+												(void**)&ORIGINAL_FUNCTION_NAME##_reenter );						\
+				}																									\
+				return result;																						\
+			}																										\
+			static ORIGINAL_FUNCTION_RETURN_TYPE replacement ORIGINAL_FUNCTION_ARGS {
+
+#define END_MACH_OVERRIDE( ORIGINAL_FUNCTION_NAME )																	\
+			}																										\
+		};																											\
+																													\
+		err = mach_override_class__##ORIGINAL_FUNCTION_NAME::override((void*)ORIGINAL_FUNCTION_NAME);				\
+	}
+ 
+#endif
+
+#ifdef	__cplusplus
+	}
+#endif
+#endif	//	_mach_override_