Redo commit 932945d4808e37ba0ca1a953571187f445e24f41

This time, make sure the object for disabling XSave support in msvcr can't be dropped by the linker.

1 files changed, 25 insertions, 26 deletions

diff --git a/Source/Core/Common/XSaveWorkaround.cpp b/Source/Core/Common/XSaveWorkaround.cpp
index 30a2a42b2b..b54f33eb4b 100644
--- a/Source/Core/Common/XSaveWorkaround.cpp
+++ b/Source/Core/Common/XSaveWorkaround.cpp
@@ -2,39 +2,38 @@
 // Licensed under GPLv2
 // Refer to the license.txt file included.
 
-#if defined(_WIN32) && defined(_ARCH_64)
+#if defined(_WIN32) && defined(_M_X86_64)
 
 #include <math.h>
 #include <Windows.h>
 
-// This puts the rest of this translation unit into a segment which is
-// initialized by the CRT *before* any of the other code (including C++
-// static initializers).
-#pragma warning(disable : 4075)
-#pragma init_seg(".CRT$XCB")
-
-struct EnableXSaveWorkaround
+void EnableXSaveWorkaround()
 {
-	EnableXSaveWorkaround()
+	// Some Windows environments may have hardware support for AVX/FMA,
+	// but the OS does not support it. The CRT math library does not support
+	// this scenario, so we have to manually tell it not to use FMA3
+	// instructions.
+
+	// The API name is somewhat misleading - we're testing for OS support
+	// here.
+	if (!IsProcessorFeaturePresent(PF_XSAVE_ENABLED))
 	{
-		// Some Windows environments may have hardware support for AVX/FMA,
-		// but the OS does not support it. The CRT math library does not support
-		// this scenario, so we have to manually tell it not to use FMA3
-		// instructions.
-
-		// The API name is somewhat misleading - we're testing for OS support
-		// here.
-		if (!IsProcessorFeaturePresent(PF_XSAVE_ENABLED))
-		{
-			_set_FMA3_enable(0);
-		}
+		_set_FMA3_enable(0);
 	}
+}
+
+// Create a segment which is recognized by the linker to be part of the CRT
+// initialization. XI* = C startup, XC* = C++ startup. "A" placement is reserved
+// for system use. Thus, the earliest we can get is XIB (C startup is before
+// C++).
+#pragma section(".CRT$XIB", read)
+
+// Place a symbol in the special segment, make it have C linkage so that
+// referencing it doesn't require ugly decorated names.
+// Use /include:XSaveWorkaround linker flag to enable this.
+extern "C" {
+	__declspec(allocate(".CRT$XIB"))
+	decltype(&EnableXSaveWorkaround) XSaveWorkaround = EnableXSaveWorkaround;
 };
 
-static EnableXSaveWorkaround enableXSaveWorkaround;
-
-// N.B. Any code after this will still be in the .CRT$XCB segment. Please just
-// do not append any code here unless it is intended to be executed before
-// static initializers.
-
 #endif