Delete !FEATURE_SYNCTABLE (dotnet#1343)

MichalStrehovsky · Jul 20, 2021 · 6415571 · 6415571
1 parent b3862bf
commit 6415571
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Showing 3 changed files with 2 additions and 68 deletions.
diff --git a/src/coreclr/nativeaot/System.Private.CoreLib/src/System.Private.CoreLib.csproj b/src/coreclr/nativeaot/System.Private.CoreLib/src/System.Private.CoreLib.csproj
@@ -17,10 +17,6 @@
     <RuntimeBasePath>..\..\Runtime.Base\src\</RuntimeBasePath>
   </PropertyGroup>
 
-  <PropertyGroup>
-    <UseSyncTable>true</UseSyncTable>
-    <DefineConstants Condition="'$(UseSyncTable)' == 'true'">FEATURE_SYNCTABLE;$(DefineConstants)</DefineConstants>
-  </PropertyGroup>
   <PropertyGroup>
     <FeaturePortableThreadPool Condition="'$(FeaturePortableThreadPool)' == ''">false</FeaturePortableThreadPool>
     <FeaturePortableThreadPool Condition="'$(TargetsUnix)' == 'true'">true</FeaturePortableThreadPool>
@@ -229,9 +225,9 @@
     <Compile Include="System\Threading\Interlocked.cs" />
     <Compile Include="System\Threading\LockHolder.cs" />
     <Compile Include="System\Threading\Monitor.CoreRT.cs" />
-    <Compile Include="System\Threading\ObjectHeader.cs" Condition="'$(UseSyncTable)' == 'true'" />
+    <Compile Include="System\Threading\ObjectHeader.cs" />
     <Compile Include="System\Threading\Overlapped.cs" />
-    <Compile Include="System\Threading\SyncTable.cs" Condition="'$(UseSyncTable)' == 'true'" />
+    <Compile Include="System\Threading\SyncTable.cs" />
     <Compile Include="System\Threading\Thread.CoreRT.cs" />
     <Compile Include="System\Threading\ThreadPool.CoreRT.cs" />
     <Compile Include="System\Type.CoreRT.cs" />

diff --git a/...veaot/System.Private.CoreLib/src/System/Runtime/CompilerServices/RuntimeHelpers.CoreRT.cs b/...veaot/System.Private.CoreLib/src/System/Runtime/CompilerServices/RuntimeHelpers.CoreRT.cs
@@ -81,11 +81,6 @@ public static object GetObjectValue(object? obj)
             return RuntimeImports.RhCompareObjectContentsAndPadding(o1, o2);
         }
 
-#if !FEATURE_SYNCTABLE
-        private const int HASHCODE_BITS = 26;
-        private const int MASK_HASHCODE = (1 << HASHCODE_BITS) - 1;
-#endif
-
         [ThreadStatic]
         private static int t_hashSeed;
 
@@ -101,57 +96,9 @@ internal static int GetNewHashCode()
 
         public static unsafe int GetHashCode(object o)
         {
-#if FEATURE_SYNCTABLE
             return ObjectHeader.GetHashCode(o);
-#else
-            if (o == null)
-                return 0;
-
-            fixed (IntPtr* pEEType = &o.m_pEEType)
-            {
-                int* pSyncBlockIndex = (int*)((byte*)pEEType - 4); // skipping exactly 4 bytes for the SyncTableEntry (exactly 4 bytes not a pointer size).
-                int hash = *pSyncBlockIndex & MASK_HASHCODE;
-
-                if (hash == 0)
-                    return MakeHashCode(o, pSyncBlockIndex);
-                else
-                    return hash;
-            }
-#endif
         }
 
-#if !FEATURE_SYNCTABLE
-        private static unsafe int MakeHashCode(Object o, int* pSyncBlockIndex)
-        {
-            int hash = GetNewHashCode() & MASK_HASHCODE;
-
-            if (hash == 0)
-                hash = 1;
-
-            while (true)
-            {
-                int oldIndex = Volatile.Read(ref *pSyncBlockIndex);
-
-                int currentHash = oldIndex & MASK_HASHCODE;
-                if (currentHash != 0)
-                {
-                    // Someone else set the hash code.
-                    hash = currentHash;
-                    break;
-                }
-
-                int newIndex = oldIndex | hash;
-
-                if (Interlocked.CompareExchange(ref *pSyncBlockIndex, newIndex, oldIndex) == oldIndex)
-                    break;
-                // If we get here someone else modified the header.  They may have set the hash code, or maybe some
-                // other bits.  Let's try again.
-            }
-
-            return hash;
-        }
-#endif
-
         public static int OffsetToStringData
         {
             // This offset is baked in by string indexer intrinsic, so there is no harm

diff --git a/src/coreclr/nativeaot/System.Private.CoreLib/src/System/Threading/Monitor.CoreRT.cs b/src/coreclr/nativeaot/System.Private.CoreLib/src/System/Threading/Monitor.CoreRT.cs
@@ -24,11 +24,6 @@ public static partial class Monitor
     {
         #region Object->Lock/Condition mapping
 
-#if !FEATURE_SYNCTABLE
-        private static ConditionalWeakTable<object, Lock> s_lockTable = new ConditionalWeakTable<object, Lock>();
-        private static ConditionalWeakTable<object, Lock>.CreateValueCallback s_createLock = (o) => new Lock();
-#endif
-
         private static ConditionalWeakTable<object, Condition> s_conditionTable = new ConditionalWeakTable<object, Condition>();
         private static ConditionalWeakTable<object, Condition>.CreateValueCallback s_createCondition = (o) => new Condition(GetLock(o));
 
@@ -40,11 +35,7 @@ internal static Lock GetLock(object obj)
             Debug.Assert(!(obj is Lock),
                 "Do not use Monitor.Enter or TryEnter on a Lock instance; use Lock methods directly instead.");
 
-#if FEATURE_SYNCTABLE
             return ObjectHeader.GetLockObject(obj);
-#else
-            return s_lockTable.GetValue(obj, s_createLock);
-#endif
         }
 
         private static Condition GetCondition(object obj)