WIP - Add Json feature switch to remove Ref.Emit code.

Contributes to dotnet#38693
eerhardt · May 11, 2021 · 59c60c6 · 59c60c6
1 parent 138b73e
commit 59c60c6
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Showing 3 changed files with 25 additions and 2 deletions.
diff --git a/src/libraries/System.Text.Json/src/ILLink/ILLink.Substitutions.xml b/src/libraries/System.Text.Json/src/ILLink/ILLink.Substitutions.xml
@@ -0,0 +1,7 @@
+<linker>
+  <assembly fullname="System.Text.Json">
+    <type fullname="System.Text.Json.JsonSerializerOptions">
+      <method signature="System.Boolean get_MinSizeOpts()" body="stub" value="true" feature="System.Text.Json.MinSizeOpts" featurevalue="true" />
+    </type>
+  </assembly>
+</linker>
diff --git a/src/libraries/System.Text.Json/src/System.Text.Json.csproj b/src/libraries/System.Text.Json/src/System.Text.Json.csproj
@@ -1,4 +1,4 @@
-<Project Sdk="Microsoft.NET.Sdk">
+<Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
     <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
     <TargetFrameworks>$(NetCoreAppCurrent);netstandard2.0;netcoreapp3.0;net461</TargetFrameworks>
@@ -19,6 +19,12 @@
     <!-- Use the contract reference path for ApiCompat. -->
     <ContractTargetFramework Condition="'$(TargetFramework)' == 'netcoreapp3.0'">netstandard2.0</ContractTargetFramework>
   </PropertyGroup>
+  <PropertyGroup>
+    <ILLinkDirectory>$(MSBuildThisFileDirectory)ILLink\</ILLinkDirectory>
+  </PropertyGroup>
+  <ItemGroup>
+    <ILLinkSubstitutionsXmls Include="$(ILLinkDirectory)ILLink.Substitutions.xml" />
+  </ItemGroup>
   <ItemGroup>
     <Compile Include="$(CommonPath)System\HexConverter.cs" Link="Common\System\HexConverter.cs" />
     <Compile Include="$(CommonPath)System\Text\Json\PooledByteBufferWriter.cs" Link="Common\System\Text\Json\PooledByteBufferWriter.cs" />

diff --git a/src/libraries/System.Text.Json/src/System/Text/Json/Serialization/JsonSerializerOptions.cs b/src/libraries/System.Text.Json/src/System/Text/Json/Serialization/JsonSerializerOptions.cs
@@ -22,6 +22,9 @@ public sealed partial class JsonSerializerOptions
 
         internal static readonly JsonSerializerOptions s_defaultOptions = new JsonSerializerOptions();
 
+        private static bool MinSizeOpts { get; } =
+            AppContext.TryGetSwitch("System.Text.Json.MinSizeOpts", out bool minSizeOpts) ? minSizeOpts : false;
+
         private readonly ConcurrentDictionary<Type, JsonTypeInfo> _classes = new ConcurrentDictionary<Type, JsonTypeInfo>();
 
         // Simple LRU cache for the public (de)serialize entry points that avoid some lookups in _classes.
@@ -560,7 +563,14 @@ internal MemberAccessor MemberAccessorStrategy
                 if (_memberAccessorStrategy == null)
                 {
 #if NETFRAMEWORK || NETCOREAPP
-                    _memberAccessorStrategy = new ReflectionEmitMemberAccessor();
+                    if (MinSizeOpts)
+                    {
+                        _memberAccessorStrategy = new ReflectionMemberAccessor();
+                    }
+                    else
+                    {
+                        _memberAccessorStrategy = new ReflectionEmitMemberAccessor();
+                    }
 #else
                     _memberAccessorStrategy = new ReflectionMemberAccessor();
 #endif