From ef1e2ab328087c61a6878c1e84f4fc5d710aebce Mon Sep 17 00:00:00 2001
From: dotnet-bot <dotnet-bot@microsoft.com>
Date: Fri, 30 Jan 2015 14:14:42 -0800
Subject: Initial commit to populate CoreCLR repo

[tfs-changeset: 1407945]
---
 src/vm/typeequivalencehash.hpp | 117 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 117 insertions(+)
 create mode 100644 src/vm/typeequivalencehash.hpp

(limited to 'src/vm/typeequivalencehash.hpp')

diff --git a/src/vm/typeequivalencehash.hpp b/src/vm/typeequivalencehash.hpp
new file mode 100644
index 0000000000..73912ba114
--- /dev/null
+++ b/src/vm/typeequivalencehash.hpp
@@ -0,0 +1,117 @@
+//
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+//
+
+// 
+// Hash table associated with each module that records for all types defined in that module the mapping
+// between type name and token (or TypeHandle).
+//
+
+#ifndef __TYPEEQUIVALENCE_HASH_INCLUDED
+#define __TYPEEQUIVALENCE_HASH_INCLUDED
+
+#include "ngenhash.h"
+
+#ifdef FEATURE_TYPEEQUIVALENCE
+
+// The type of each entry in the hash.
+typedef DPTR(struct TypeEquivalenceEntry) PTR_TypeEquivalenceEntry;
+typedef struct TypeEquivalenceEntry
+{
+    static NgenHashValue HashTypeHandles(TypeHandle thA, TypeHandle thB)
+    {
+        LIMITED_METHOD_CONTRACT;
+
+        UINT_PTR aPtr = thA.AsTAddr();
+        UINT_PTR bPtr = thB.AsTAddr();
+        DWORD hash = (DWORD)((aPtr + bPtr) >> 3);
+
+        return hash;
+    }
+
+    bool Match(TypeHandle thA, TypeHandle thB)
+    {
+        LIMITED_METHOD_CONTRACT;
+
+        return (((thA == m_thA) && (thB == m_thB)) ||
+            ((thB == m_thA) && (thA == m_thB)));
+    }
+
+    void SetData(TypeHandle thA, TypeHandle thB, bool fEquivalent)
+    {
+        LIMITED_METHOD_CONTRACT;
+
+        m_thA = thA;
+        m_thB = thB;
+        m_fEquivalent = fEquivalent;
+    }
+
+    bool GetEquivalence()
+    {
+        LIMITED_METHOD_CONTRACT;
+        return m_fEquivalent;
+    }
+
+private:
+
+    TypeHandle m_thA;
+    TypeHandle m_thB;
+    bool       m_fEquivalent;
+} TypeEquivalenceEntry_t;
+
+// The hash type itself. All common logic is provided by the NgenHashTable templated base class. See
+// NgenHash.h for details.
+typedef DPTR(class TypeEquivalenceHashTable) PTR_TypeEquivalenceHashTable;
+class TypeEquivalenceHashTable : public NgenHashTable<TypeEquivalenceHashTable, TypeEquivalenceEntry, 4>
+{
+    friend class NgenHashTable<TypeEquivalenceHashTable, TypeEquivalenceEntry, 4>;
+#ifdef DACCESS_COMPILE
+    friend class NativeImageDumper;
+#endif
+
+public:
+    typedef enum EquivalenceMatch
+    {
+        MatchUnknown,
+        Match,
+        NoMatch
+    };
+
+    // The LookupContext type we export to track GetValue/FindNextNestedClass enumerations is simply a rename
+    // of the base classes' hash value enumerator.
+    typedef NgenHashTable<TypeEquivalenceHashTable, TypeEquivalenceEntry, 4>::LookupContext LookupContext;
+
+#ifndef DACCESS_COMPILE
+    static TypeEquivalenceHashTable *Create(AppDomain *pDomain, DWORD dwNumBuckets, CrstExplicitInit *pCrst);
+    void RecordEquivalence(TypeHandle thA, TypeHandle thB, EquivalenceMatch match);
+#endif
+    EquivalenceMatch CheckEquivalence(TypeHandle thA, TypeHandle thB);
+
+#ifdef DACCESS_COMPILE
+    void EnumMemoryRegionsForEntry(TypeEquivalenceEntry_t *pEntry, CLRDataEnumMemoryFlags flags) { return; }
+#endif
+
+#if defined(FEATURE_PREJIT) && !defined(DACCESS_COMPILE)
+private:
+
+    bool ShouldSave(DataImage *pImage, TypeEquivalenceEntry_t *pEntry) { return false; }
+    bool IsHotEntry(TypeEquivalenceEntry_t *pEntry, CorProfileData *pProfileData) { return false; }
+    bool SaveEntry(DataImage *pImage, CorProfileData *pProfileData, TypeEquivalenceEntry_t *pOldEntry, TypeEquivalenceEntry_t *pNewEntry, EntryMappingTable *pMap) { return true; }
+    void FixupEntry(DataImage *pImage, TypeEquivalenceEntry_t *pEntry, void *pFixupBase, DWORD cbFixupOffset) { return; }
+#endif // FEATURE_PREJIT && !DACCESS_COMPILE
+
+private:
+#ifndef DACCESS_COMPILE
+    TypeEquivalenceHashTable(LoaderHeap *pHeap, DWORD cInitialBuckets, CrstExplicitInit *pCrst) :
+        NgenHashTable<TypeEquivalenceHashTable, TypeEquivalenceEntry, 4>(NULL, pHeap, cInitialBuckets),
+        m_pHashTableCrst(pCrst)
+    {
+    }
+#endif
+    CrstExplicitInit*               m_pHashTableCrst;
+};
+
+#endif // FEATURE_TYPEEQUIVALENCE
+
+#endif // !__CLASS_HASH_INCLUDED
-- 
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