1 files changed, 148 insertions, 0 deletions
diff --git a/src/gc/env/gcenv.object.h b/src/gc/env/gcenv.object.h
new file mode 100644
index 0000000000..c999e4538e
--- /dev/null
+++ b/src/gc/env/gcenv.object.h
@@ -0,0 +1,148 @@
+// 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.
+
+//-------------------------------------------------------------------------------------------------
+//
+// Low-level types describing GC object layouts.
+//
+
+// Bits stolen from the sync block index that the GC/HandleTable knows about (currently these are at the same
+// positions as the mainline runtime but we can change this below when it becomes apparent how Redhawk will
+// handle sync blocks).
+#define BIT_SBLK_GC_RESERVE                 0x20000000
+#define BIT_SBLK_FINALIZER_RUN              0x40000000
+
+// The sync block index header (small structure that immediately precedes every object in the GC heap). Only
+// the GC uses this so far, and only to store a couple of bits of information.
+class ObjHeader
+{
+private:
+#if defined(BIT64)
+    uint32_t m_uAlignpad;
+#endif // BIT64
+    uint32_t m_uSyncBlockValue;
+
+public:
+    uint32_t GetBits() { return m_uSyncBlockValue; }
+    void SetBit(uint32_t uBit) { Interlocked::Or(&m_uSyncBlockValue, uBit); }
+    void ClrBit(uint32_t uBit) { Interlocked::And(&m_uSyncBlockValue, ~uBit); }
+    void SetGCBit() { m_uSyncBlockValue |= BIT_SBLK_GC_RESERVE; }
+    void ClrGCBit() { m_uSyncBlockValue &= ~BIT_SBLK_GC_RESERVE; }
+};
+
+#define MTFlag_ContainsPointers 1
+#define MTFlag_HasFinalizer 2
+#define MTFlag_IsArray 4
+
+class MethodTable
+{
+public:
+    uint16_t    m_componentSize;
+    uint16_t    m_flags;
+    uint32_t    m_baseSize;
+
+    MethodTable * m_pRelatedType;
+
+public:
+    void InitializeFreeObject()
+    {
+        m_baseSize = 3 * sizeof(void *);
+        m_componentSize = 1;
+        m_flags = 0;
+    }
+
+    uint32_t GetBaseSize()
+    {
+        return m_baseSize;
+    }
+
+    uint16_t RawGetComponentSize()
+    {
+        return m_componentSize;
+    }
+
+    bool ContainsPointers()
+    {
+        return (m_flags & MTFlag_ContainsPointers) != 0;
+    }
+
+    bool ContainsPointersOrCollectible()
+    {
+        return ContainsPointers();
+    }
+
+    bool HasComponentSize()
+    {
+        return m_componentSize != 0;
+    }
+
+    bool HasFinalizer()
+    {
+        return (m_flags & MTFlag_HasFinalizer) != 0;
+    }
+
+    bool HasCriticalFinalizer()
+    {
+        return false;
+    }
+
+    bool IsArray()
+    {
+        return (m_flags & MTFlag_IsArray) != 0;
+    }
+
+    MethodTable * GetParent()
+    {
+        _ASSERTE(!IsArray());
+        return m_pRelatedType;
+    }
+
+    bool SanityCheck()
+    {
+        return true;
+    }
+};
+
+class Object
+{
+    MethodTable * m_pMethTab;
+
+public:
+    ObjHeader * GetHeader()
+    { 
+        return ((ObjHeader *)this) - 1;
+    }
+
+    MethodTable * RawGetMethodTable() const
+    {
+        return m_pMethTab;
+    }
+
+    MethodTable * GetGCSafeMethodTable() const
+    {
+        return (MethodTable *)((uintptr_t)m_pMethTab & ~3);
+    }
+
+    void RawSetMethodTable(MethodTable * pMT)
+    {
+        m_pMethTab = pMT;
+    }
+};
+#define MIN_OBJECT_SIZE     (2*sizeof(uint8_t*) + sizeof(ObjHeader))
+
+class ArrayBase : public Object
+{
+    uint32_t m_dwLength;
+
+public:
+    uint32_t GetNumComponents()
+    {
+        return m_dwLength;
+    }
+
+    static size_t GetOffsetOfNumComponents()
+    {
+        return offsetof(ArrayBase, m_dwLength);
+    }
+};