Move NullRefs to Unsafe

dotnet · Oct 12, 2019 · 28fa945 · 28fa945
1 parent 559d375
commit 28fa945
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Showing 7 changed files with 29 additions and 17 deletions.
diff --git a/src/System.Private.CoreLib/shared/Internal/Runtime/CompilerServices/Unsafe.cs b/src/System.Private.CoreLib/shared/Internal/Runtime/CompilerServices/Unsafe.cs
@@ -387,5 +387,21 @@ public static IntPtr ByteOffset<T>(ref T origin, ref T target)
         {
             throw new PlatformNotSupportedException();
         }
+
+        /// <summary>
+        /// Determines the byte offset from origin to target from the given references.
+        /// </summary>
+        [NonVersionable]
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        internal static unsafe bool IsNullRef<T>(in T value)
+            => Unsafe.AsPointer(ref Unsafe.AsRef(in value!)) == null ? true : false;
+
+        /// <summary>
+        /// Determines the byte offset from origin to target from the given references.
+        /// </summary>
+        [NonVersionable]
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        internal static unsafe ref T NullRef<T>()
+            => ref Unsafe.AsRef<T>(null);
     }
 }
diff --git a/src/System.Private.CoreLib/shared/System/Collections/Generic/Dictionary.cs b/src/System.Private.CoreLib/shared/System/Collections/Generic/Dictionary.cs
@@ -8,6 +8,8 @@
 using System.Runtime.Serialization;
 using System.Runtime.InteropServices;
 
+using Internal.Runtime.CompilerServices;
+
 namespace System.Collections.Generic
 {
     /// <summary>
@@ -171,7 +173,7 @@ public TValue this[TKey key]
             get
             {
                 ref TValue value = ref FindValueOrNull(key);
-                if (!RuntimeHelpers.IsNullRef(in value))
+                if (!Unsafe.IsNullRef(in value))
                 {
                     return value;
                 }
@@ -197,7 +199,7 @@ void ICollection<KeyValuePair<TKey, TValue>>.Add(KeyValuePair<TKey, TValue> keyV
         bool ICollection<KeyValuePair<TKey, TValue>>.Contains(KeyValuePair<TKey, TValue> keyValuePair)
         {
             ref TValue value = ref FindValueOrNull(keyValuePair.Key);
-            if (!RuntimeHelpers.IsNullRef(in value) && EqualityComparer<TValue>.Default.Equals(value, keyValuePair.Value))
+            if (!Unsafe.IsNullRef(in value) && EqualityComparer<TValue>.Default.Equals(value, keyValuePair.Value))
             {
                 return true;
             }
@@ -207,7 +209,7 @@ bool ICollection<KeyValuePair<TKey, TValue>>.Contains(KeyValuePair<TKey, TValue>
         bool ICollection<KeyValuePair<TKey, TValue>>.Remove(KeyValuePair<TKey, TValue> keyValuePair)
         {
             ref TValue value = ref FindValueOrNull(keyValuePair.Key);
-            if (!RuntimeHelpers.IsNullRef(in value) && EqualityComparer<TValue>.Default.Equals(value, keyValuePair.Value))
+            if (!Unsafe.IsNullRef(in value) && EqualityComparer<TValue>.Default.Equals(value, keyValuePair.Value))
             {
                 Remove(keyValuePair.Key);
                 return true;
@@ -235,7 +237,7 @@ public void Clear()
         public bool ContainsKey(TKey key)
         {
             ref TValue value = ref FindValueOrNull(key);
-            return !RuntimeHelpers.IsNullRef(in value);
+            return !Unsafe.IsNullRef(in value);
         }
 
         public bool ContainsValue(TValue value)
@@ -339,7 +341,7 @@ private ref TValue FindValueOrNull(TKey key)
             int[]? buckets = _buckets;
             Entry[]? entries = _entries;
             int collisionCount = 0;
-            ref TValue value = ref RuntimeHelpers.CreateNullRef<TValue>();
+            ref TValue value = ref Unsafe.NullRef<TValue>();
             if (buckets != null)
             {
                 Debug.Assert(entries != null, "expected entries to be != null");
@@ -869,7 +871,7 @@ public bool Remove(TKey key, [MaybeNullWhen(false)] out TValue value)
         public bool TryGetValue(TKey key, [MaybeNullWhen(false)] out TValue value)
         {
             ref TValue entry = ref FindValueOrNull(key);
-            if (!RuntimeHelpers.IsNullRef(in entry))
+            if (!Unsafe.IsNullRef(in entry))
             {
                 value = entry;
                 return true;
@@ -1037,7 +1039,7 @@ public void TrimExcess(int capacity)
                 if (IsCompatibleKey(key))
                 {
                     ref TValue value = ref FindValueOrNull((TKey)key);
-                    if (!RuntimeHelpers.IsNullRef(in value))
+                    if (!Unsafe.IsNullRef(in value))
                     {
                         return value;
                     }

diff --git a/src/System.Private.CoreLib/shared/System/Memory.cs b/src/System.Private.CoreLib/shared/System/Memory.cs
@@ -295,7 +295,7 @@ public unsafe Span<T> Span
                 // in which case that's the dangerous operation performed by the dev, and we're just following
                 // suit here to make it work as best as possible.
 
-                ref T refToReturn = ref RuntimeHelpers.CreateNullRef<T>();
+                ref T refToReturn = ref Unsafe.NullRef<T>();
                 int lengthOfUnderlyingSpan = 0;
 
                 // Copy this field into a local so that it can't change out from under us mid-operation.

diff --git a/src/System.Private.CoreLib/shared/System/ReadOnlyMemory.cs b/src/System.Private.CoreLib/shared/System/ReadOnlyMemory.cs
@@ -217,7 +217,7 @@ public unsafe ReadOnlySpan<T> Span
             [MethodImpl(MethodImplOptions.AggressiveInlining)]
             get
             {
-                ref T refToReturn = ref RuntimeHelpers.CreateNullRef<T>();
+                ref T refToReturn = ref Unsafe.NullRef<T>();
                 int lengthOfUnderlyingSpan = 0;
 
                 // Copy this field into a local so that it can't change out from under us mid-operation.

diff --git a/src/System.Private.CoreLib/shared/System/ReadOnlySpan.Fast.cs b/src/System.Private.CoreLib/shared/System/ReadOnlySpan.Fast.cs
@@ -151,7 +151,7 @@ public ref readonly T this[int index]
         public ref readonly T GetPinnableReference()
         {
             // Ensure that the native code has just one forward branch that is predicted-not-taken.
-            ref T ret = ref RuntimeHelpers.CreateNullRef<T>();
+            ref T ret = ref Unsafe.NullRef<T>();
             if (_length != 0) ret = ref _pointer.Value;
             return ref ret;
         }

diff --git a/src/System.Private.CoreLib/shared/System/Runtime/CompilerServices/RuntimeHelpers.cs b/src/System.Private.CoreLib/shared/System/Runtime/CompilerServices/RuntimeHelpers.cs
@@ -80,11 +80,5 @@ public static void PrepareConstrainedRegions()
         public static void PrepareConstrainedRegionsNoOP()
         {
         }
-
-        internal static unsafe bool IsNullRef<T>(in T value)
-            => Unsafe.AsPointer(ref Unsafe.AsRef(in value!)) == null ? true : false;
-
-        internal static unsafe ref T CreateNullRef<T>()
-            => ref Unsafe.AsRef<T>(null);
     }
 }
diff --git a/src/System.Private.CoreLib/shared/System/Span.Fast.cs b/src/System.Private.CoreLib/shared/System/Span.Fast.cs
@@ -157,7 +157,7 @@ public ref T this[int index]
         public unsafe ref T GetPinnableReference()
         {
             // Ensure that the native code has just one forward branch that is predicted-not-taken.
-            ref T ret = ref RuntimeHelpers.CreateNullRef<T>();
+            ref T ret = ref Unsafe.NullRef<T>();
             if (_length != 0) ret = ref _pointer.Value;
             return ref ret;
         }