1 files changed, 82 insertions, 0 deletions
diff --git a/src/inc/gcinfo.h b/src/inc/gcinfo.h
new file mode 100644
index 0000000000..8d249a38a6
--- /dev/null
+++ b/src/inc/gcinfo.h
@@ -0,0 +1,82 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+
+/*****************************************************************************/
+#ifndef _GCINFO_H_
+#define _GCINFO_H_
+/*****************************************************************************/
+
+#include "daccess.h"
+#include "windef.h"     // For BYTE
+
+// Some declarations in this file are used on non-x86 platforms, but most are x86-specific.
+
+// Use the lower 2 bits of the offsets stored in the tables
+// to encode properties
+
+const unsigned        OFFSET_MASK  = 0x3;  // mask to access the low 2 bits
+
+//
+//  Note for untracked locals the flags allowed are "pinned" and "byref"
+//   and for tracked locals the flags allowed are "this" and "byref"
+//  Note that these definitions should also match the definitions of
+//   GC_CALL_INTERIOR and GC_CALL_PINNED in VM/gc.h
+//
+const unsigned  byref_OFFSET_FLAG  = 0x1;  // the offset is an interior ptr
+const unsigned pinned_OFFSET_FLAG  = 0x2;  // the offset is a pinned ptr
+const unsigned   this_OFFSET_FLAG  = 0x2;  // the offset is "this"
+
+//-----------------------------------------------------------------------------
+// The current GCInfo Version
+//-----------------------------------------------------------------------------
+
+#ifdef _TARGET_X86_
+// X86 GcInfo encoding is yet to be changed.
+#define GCINFO_VERSION 1
+#else
+#define GCINFO_VERSION 2
+#endif // _TARGET_X86_
+
+#define MIN_GCINFO_VERSION_WITH_RETURN_KIND 2
+#define MIN_GCINFO_VERSION_WITH_REV_PINVOKE_FRAME 2
+//-----------------------------------------------------------------------------
+// GCInfoToken: A wrapper that contains the GcInfo data and version number.
+//
+// The version# is not stored in the GcInfo structure -- because it is
+// wasteful to store the version once for every method.
+// Instead, the version# istracked per range-section of generated/loaded methods.
+//
+// The GCInfo version is computed as :
+// 1) The current GCINFO_VERSION for JITted and Ngened images
+// 2) A function of the Ready - to - run major version stored in READYTORUN_HEADER
+//   for ready - to - run images.ReadyToRunJitManager::JitTokenToGCInfoVersion()
+//   provides the GcInfo version for any Method. 
+//-----------------------------------------------------------------------------
+
+struct GCInfoToken
+{
+    PTR_VOID Info;
+    UINT32 Version;
+
+    BOOL IsReturnKindAvailable() 
+    {
+        return (Version >= MIN_GCINFO_VERSION_WITH_RETURN_KIND);
+    }
+    BOOL IsReversePInvokeFrameAvailable() 
+    {
+        return (Version >= MIN_GCINFO_VERSION_WITH_REV_PINVOKE_FRAME);
+    }
+
+    static UINT32 ReadyToRunVersionToGcInfoVersion(UINT32 readyToRunMajorVersion)
+    {
+        // GcInfo version is 1 up to ReadyTorun version 1.x
+        // GcInfo version is current from  ReadyToRun version 2.0
+        return (readyToRunMajorVersion == 1) ? 1 : GCINFO_VERSION;
+    }
+};
+
+/*****************************************************************************/
+#endif //_GCINFO_H_
+/*****************************************************************************/