Avoid Unsafe.As<char, ushort> reinterpret casts by introducing string…

….GetRawStringDataAsUshort() internal method
dotnet · Jul 20, 2022 · 5d92816 · 5d92816
1 parent ed83650
commit 5d92816
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Showing 2 changed files with 5 additions and 4 deletions.
diff --git a/src/libraries/System.Private.CoreLib/src/System/String.Manipulation.cs b/src/libraries/System.Private.CoreLib/src/System/String.Manipulation.cs
@@ -1006,8 +1006,8 @@ public string Replace(char oldChar, char newChar)
             }
 
             // Copy the remaining characters, doing the replacement as we go.
-            ref ushort pSrc = ref Unsafe.Add(ref Unsafe.As<char, ushort>(ref _firstChar), (nint)(uint)copyLength);
-            ref ushort pDst = ref Unsafe.Add(ref Unsafe.As<char, ushort>(ref result._firstChar), (nint)(uint)copyLength);
+            ref ushort pSrc = ref Unsafe.Add(ref GetRawStringDataAsUshort(), (nint)(uint)copyLength);
+            ref ushort pDst = ref Unsafe.Add(ref result.GetRawStringDataAsUshort(), (nint)(uint)copyLength);
             nint i = 0;
 
             if (Vector.IsHardwareAccelerated && Length >= Vector<ushort>.Count)
@@ -1044,10 +1044,10 @@ public string Replace(char oldChar, char newChar)
                 // additional check which would introduce a branch here.
 
                 i = (nint)(uint)Length - Vector<ushort>.Count;
-                original = Vector.LoadUnsafe(ref Unsafe.As<char, ushort>(ref _firstChar), i);
+                original = Vector.LoadUnsafe(ref GetRawStringDataAsUshort(), i);
                 equals = Vector.Equals(original, oldChars);
                 results = Vector.ConditionalSelect(equals, newChars, original);
-                results.StoreUnsafe(ref Unsafe.As<char, ushort>(ref result._firstChar), i);
+                results.StoreUnsafe(ref result.GetRawStringDataAsUshort(), i);
             }
             else
             {

diff --git a/src/libraries/System.Private.CoreLib/src/System/String.cs b/src/libraries/System.Private.CoreLib/src/System/String.cs
@@ -508,6 +508,7 @@ public static bool IsNullOrWhiteSpace([NotNullWhen(false)] string? value)
         public ref readonly char GetPinnableReference() => ref _firstChar;
 
         internal ref char GetRawStringData() => ref _firstChar;
+        internal ref ushort GetRawStringDataAsUshort() => ref Unsafe.As<char, ushort>(ref _firstChar);
 
         // Helper for encodings so they can talk to our buffer directly
         // stringLength must be the exact size we'll expect