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togl/linuxwin/intelglmallocworkaround.cpp

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+//========= Copyright Valve Corporation, All rights reserved. ============//
+//                       TOGL CODE LICENSE
+//
+//  Copyright 2011-2014 Valve Corporation
+//  All Rights Reserved.
+//
+//  Permission is hereby granted, free of charge, to any person obtaining a copy
+//  of this software and associated documentation files (the "Software"), to deal
+//  in the Software without restriction, including without limitation the rights
+//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+//  copies of the Software, and to permit persons to whom the Software is
+//  furnished to do so, subject to the following conditions:
+//
+//  The above copyright notice and this permission notice shall be included in
+//  all copies or substantial portions of the Software.
+//
+//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+//  THE SOFTWARE.
+#include "intelglmallocworkaround.h"
+#include "mach_override.h"
+
+// memdbgon -must- be the last include file in a .cpp file.
+#include "tier0/memdbgon.h"
+
+IntelGLMallocWorkaround* IntelGLMallocWorkaround::s_pWorkaround = NULL;
+
+void *IntelGLMallocWorkaround::ZeroingAlloc(size_t size)
+{
+	// We call into this pointer that resumes the original malloc.
+	void *memory = s_pWorkaround->m_pfnMallocReentry(size);
+	if (size < 96)
+	{
+		// Since the Intel driver has an issue with a small allocation 
+		// that's left uninitialized, we use memset to ensure it's zero-initialized.
+		memset(memory, 0, size);
+	}
+
+	return memory;
+}
+
+IntelGLMallocWorkaround* IntelGLMallocWorkaround::Get()
+{
+	if (!s_pWorkaround)
+	{
+		s_pWorkaround = new IntelGLMallocWorkaround();
+	}
+
+	return s_pWorkaround;
+}
+
+bool IntelGLMallocWorkaround::Enable()
+{
+	if ( m_pfnMallocReentry != NULL )
+	{
+		return true;
+	}
+
+	mach_error_t error = mach_override_ptr( (void*)&malloc, (const void*)&ZeroingAlloc, (void**)&m_pfnMallocReentry );
+	if ( error == err_cannot_override )
+	{
+		m_pfnMallocReentry = NULL;
+		return false;
+	}
+
+	return true;
+}