Improved performance of System.Reflection.Emit API (#23833)

* Improved performance of System.Reflection.Emit API * Moved heap allocation to stack * Eliminating conditional branch by casting sbyte to byte * Reduced heap allocation of ScopeTree * Removed redundant `unsafe` from function signature
dotnet · Apr 15, 2019 · 77a5f9c · 77a5f9c
1 parent 5155a67
commit 77a5f9c
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Showing 4 changed files with 150 additions and 281 deletions.
diff --git a/src/System.Private.CoreLib/src/System/Reflection/Emit/CustomAttributeBuilder.cs b/src/System.Private.CoreLib/src/System/Reflection/Emit/CustomAttributeBuilder.cs
@@ -14,12 +14,9 @@
 ===========================================================*/
 
 
-using System;
-using System.Reflection;
+using System.Buffers.Binary;
 using System.IO;
 using System.Text;
-using System.Runtime.InteropServices;
-using System.Globalization;
 using System.Diagnostics;
 
 namespace System.Reflection.Emit
@@ -305,7 +302,7 @@ private static void VerifyTypeAndPassedObjectType(Type type, Type passedType, st
             }
         }
 
-        private void EmitType(BinaryWriter writer, Type type)
+        private static void EmitType(BinaryWriter writer, Type type)
         {
             if (type.IsPrimitive)
             {
@@ -377,7 +374,7 @@ private void EmitType(BinaryWriter writer, Type type)
             }
         }
 
-        private void EmitString(BinaryWriter writer, string str)
+        private static void EmitString(BinaryWriter writer, string str)
         {
             // Strings are emitted with a length prefix in a compressed format (1, 2 or 4 bytes) as used internally by metadata.
             byte[] utf8Str = Encoding.UTF8.GetBytes(str);
@@ -388,20 +385,16 @@ private void EmitString(BinaryWriter writer, string str)
             }
             else if (length <= 0x3fff)
             {
-                writer.Write((byte)((length >> 8) | 0x80));
-                writer.Write((byte)(length & 0xff));
+                writer.Write(BinaryPrimitives.ReverseEndianness((short)(length | 0x80_00)));
             }
             else
             {
-                writer.Write((byte)((length >> 24) | 0xc0));
-                writer.Write((byte)((length >> 16) & 0xff));
-                writer.Write((byte)((length >> 8) & 0xff));
-                writer.Write((byte)(length & 0xff));
+                writer.Write(BinaryPrimitives.ReverseEndianness(length | 0xC0_00_00_00));
             }
             writer.Write(utf8Str);
         }
 
-        private void EmitValue(BinaryWriter writer, Type type, object value)
+        private static void EmitValue(BinaryWriter writer, Type type, object value)
         {
             if (type.IsEnum)
             {

diff --git a/src/System.Private.CoreLib/src/System/Reflection/Emit/DynamicILGenerator.cs b/src/System.Private.CoreLib/src/System/Reflection/Emit/DynamicILGenerator.cs
@@ -7,6 +7,7 @@
 namespace System.Reflection.Emit
 {
     using System;
+    using System.Buffers.Binary;
     using System.Globalization;
     using System.Diagnostics.SymbolStore;
     using System.Runtime.InteropServices;
@@ -723,10 +724,7 @@ internal override byte[] GetCodeInfo(
 
                 if ((header & 0x40) != 0) // Fat
                 {
-                    byte[] size = new byte[4];
-                    for (int q = 0; q < 3; q++)
-                        size[q] = m_exceptionHeader[q + 1];
-                    EHCount = (BitConverter.ToInt32(size, 0) - 4) / 24;
+                    EHCount = (BinaryPrimitives.ReadInt32LittleEndian(m_exceptionHeader.AsSpan(1)) - 4) / 24;
                 }
                 else
                     EHCount = (m_exceptionHeader[1] - 2) / 12;