- Enable backpatching for VC++ builds of ZDBSP.

SVN r2411 (trunk)

CMakeLists.txt

@@ -31,11 +31,15 @@ if( CMAKE_SIZEOF_VOID_P MATCHES "4" )
 endif( CMAKE_SIZEOF_VOID_P MATCHES "4" )
 
 if( SSE_MATTERS )
-	if( CMAKE_COMPILER_IS_GNUCXX AND WIN32 )
+	if( WIN32 )
 		set( BACKPATCH 1 CACHE BOOL "Enable backpatching." )
-	endif( CMAKE_COMPILER_IS_GNUCXX AND WIN32 )
+	else( WIN32 )
+		set( BACKPATCH 0 )
+	endif( WIN32 )
 	set( FULL_SSE2 0 CACHE BOOL "Use SSE2 math everywhere." )
 	set( SSE 1 CACHE BOOL "Build SSE and SSE2 versions of key code." )
+else( SSE_MATTERS )
+	set( BACKPATCH 0 )
 endif( SSE_MATTERS )
 
 if( CMAKE_COMPILER_IS_GNUCXX )
@@ -99,6 +103,10 @@ else( ZLIB_FOUND )
 	set( ZLIB_LIBRARY z )
 endif( ZLIB_FOUND )
 
+if( BACKPATCH )
+	add_definitions( -DBACKPATCH )
+endif( BACKPATCH )
+
 CHECK_FUNCTION_EXISTS( stricmp STRICMP_EXISTS )
 if( NOT STRICMP_EXISTS )
 	add_definitions( -Dstricmp=strcasecmp )

nodebuild.cpp

@@ -1053,19 +1053,29 @@ void FNodeBuilder::PrintSet (int l, DWORD set)
 	Printf ("*\n");
 }
 
-#if defined(_WIN32) && !defined(__SSE2__) && !defined(DISABLE_SSE) && !defined(DISABLE_BACKPATCH) && defined(__i386__) && defined(__GNUC__)
+#ifdef BACKPATCH
 #define WIN32_LEAN_AND_MEAN
 #include <windows.h>
 
+#ifdef __GNUC__
 extern "C" int ClassifyLineBackpatch (node_t &node, const FSimpleVert *v1, const FSimpleVert *v2, int sidev[2])
+#else
+static int *CallerOffset;
+int ClassifyLineBackpatchC (node_t &node, const FSimpleVert *v1, const FSimpleVert *v2, int sidev[2])
+#endif
 {
 	// Select the routine based on SSELevel and patch the caller so that
 	// they call that routine directly next time instead of going through here.
-	int *calleroffset = (int *)__builtin_return_address(0) - 1;
+	int *calleroffset;
 	int diff;
 	int (*func)(node_t &, const FSimpleVert *, const FSimpleVert *, int[2]);
 	DWORD oldprotect;
 
+#ifdef __GNUC__
+	calleroffset = (int *)__builtin_return_address(0) - 1;
+#else
+	calleroffset = CallerOffset;
+#endif
 //	printf ("Patching for SSE %d\n", SSELevel);
 
 	if (SSELevel == 2)
@@ -1094,4 +1104,23 @@ extern "C" int ClassifyLineBackpatch (node_t &node, const FSimpleVert *v1, const
 	// And return by calling the real function.
 	return func (node, v1, v2, sidev);
 }
+
+#ifndef __GNUC__
+// The ClassifyLineBackpatch() function here is a stub that uses inline assembly and nakedness
+// to retrieve the return address of the stack before sending control to the real
+// ClassifyLineBackpatchC() function. Since BACKPATCH shouldn't be defined on 64-bit builds,
+// we're okay that VC++ can't do inline assembly on that target.
+
+extern "C" __declspec(noinline) __declspec(naked) int ClassifyLineBackpatch (node_t &node, const FSimpleVert *v1, const FSimpleVert *v2, int sidev[2])
+{
+	// We store the return address in a global, so as not to need to mess with the parameter list.
+	__asm
+	{
+		mov eax, [esp]
+		sub eax, 4
+		mov CallerOffset, eax
+		jmp ClassifyLineBackpatchC
+	}
+}
+#endif
 #endif

nodebuild.h

@@ -56,8 +56,12 @@ extern "C"
 #ifndef DISABLE_SSE
 	int ClassifyLineSSE1 (node_t &node, const FSimpleVert *v1, const FSimpleVert *v2, int sidev[2]);
 	int ClassifyLineSSE2 (node_t &node, const FSimpleVert *v1, const FSimpleVert *v2, int sidev[2]);
-#if defined(_WIN32) && defined(__GNUC__) && !defined(DISABLE_BACKPATCH)
+#ifdef BACKPATCH
+#ifdef __GNUC__
 	int ClassifyLineBackpatch (node_t &node, const FSimpleVert *v1, const FSimpleVert *v2, int sidev[2]) __attribute__((noinline));
+#else
+	int __declspec(noinline) ClassifyLineBackpatch (node_t &node, const FSimpleVert *v1, const FSimpleVert *v2, int sidev[2]);
+#endif
 #endif
 #endif
 }
@@ -300,7 +304,7 @@ inline int FNodeBuilder::ClassifyLine (node_t &node, const FPrivVert *v1, const
 	return ClassifyLine2 (node, v1, v2, sidev);
 #else
 	// Select the routine based on our flag.
-#if defined(_WIN32) && defined(__GNUC__) && !defined(DISABLE_BACKPATCH)
+#ifdef BACKPATCH
 	return ClassifyLineBackpatch (node, v1, v2, sidev);
 #else
 	if (SSELevel == 2)