From 5f6a34bec123338e94511df1e22e98f180eea161 Mon Sep 17 00:00:00 2001
From: Vlad Brezae <brezaevlad@gmail.com>
Date: Fri, 28 Aug 2026 16:44:49 +0300
Subject: [PATCH 1/2] Add knob to force value of
 TargetAllowsRuntimeCodeGeneration

iOS like configuration can be obtained by passing `--target-allows-runtime-code-generation:false`
---
 src/coreclr/crossgen-corelib.proj                         | 1 +
 src/coreclr/tools/aot/crossgen2/Crossgen2RootCommand.cs   | 3 +++
 src/coreclr/tools/aot/crossgen2/Program.cs                | 3 ++-
 src/coreclr/tools/aot/crossgen2/Properties/Resources.resx | 3 +++
 4 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/src/coreclr/crossgen-corelib.proj b/src/coreclr/crossgen-corelib.proj
index 363c82d242359c..ebe09a78aa9dad 100644
--- a/src/coreclr/crossgen-corelib.proj
+++ b/src/coreclr/crossgen-corelib.proj
@@ -161,6 +161,7 @@
       <CrossGenDllCmd Condition="'$(PublishReadyToRunContainerFormat)' == 'wasm'">$(CrossGenDllCmd) "--opt-cross-module:*"</CrossGenDllCmd>
       <CrossGenDllCmd Condition="'$(UseComposite)' == 'true'">$(CrossGenDllCmd) --composite</CrossGenDllCmd>
       <CrossGenDllCmd>$(CrossGenDllCmd) --targetos:$(TargetOS)</CrossGenDllCmd>
+      <CrossGenDllCmd Condition="'$(FeatureDynamicCodeCompiled)' != ''">$(CrossGenDllCmd) --target-allows-runtime-code-generation:$(FeatureDynamicCodeCompiled)</CrossGenDllCmd>
       <CrossGenDllCmd Condition="'$(UsingToolIbcOptimization)' != 'true' and '$(EnableNgenOptimization)' == 'true'">$(CrossGenDllCmd) -m:$(MergedMibcPath) --embed-pgo-data</CrossGenDllCmd>
       <CrossGenDllCmd>$(CrossGenDllCmd) -O</CrossGenDllCmd>
       <!-- Enable type and field layout verification to make it easier to catch when the crossgen2 type layout engine and the runtime disagree on layout conventions -->
diff --git a/src/coreclr/tools/aot/crossgen2/Crossgen2RootCommand.cs b/src/coreclr/tools/aot/crossgen2/Crossgen2RootCommand.cs
index 644fe3d92b02ff..396e5b42f6e896 100644
--- a/src/coreclr/tools/aot/crossgen2/Crossgen2RootCommand.cs
+++ b/src/coreclr/tools/aot/crossgen2/Crossgen2RootCommand.cs
@@ -94,6 +94,8 @@ internal class Crossgen2RootCommand : RootCommand
             new("--maxgenericcyclebreadth") { DefaultValueFactory = _ => ReadyToRunCompilerContext.DefaultGenericCycleBreadthCutoff, Description = SR.GenericCycleBreadthCutoff };
         public Option<string> TargetOS { get; } =
             new("--targetos") { Description = SR.TargetOSOption };
+        public Option<bool?> TargetAllowsRuntimeCodeGeneration { get; } =
+            new("--target-allows-runtime-code-generation") { Description = SR.TargetAllowsRuntimeCodeGenerationOption };
         public Option<string> JitPath { get; } =
             new("--jitpath") { Description = SR.JitPathOption };
         public Option<bool> PrintReproInstructions { get; } =
@@ -199,6 +201,7 @@ public Crossgen2RootCommand(string[] args) : base(SR.Crossgen2BannerText)
             Options.Add(GenericCycleBreadthCutoff);
             Options.Add(TargetArchitecture);
             Options.Add(TargetOS);
+            Options.Add(TargetAllowsRuntimeCodeGeneration);
             Options.Add(JitPath);
             Options.Add(PrintReproInstructions);
             Options.Add(SingleMethodTypeName);
diff --git a/src/coreclr/tools/aot/crossgen2/Program.cs b/src/coreclr/tools/aot/crossgen2/Program.cs
index 691add6dd78b2a..75892ef120f613 100644
--- a/src/coreclr/tools/aot/crossgen2/Program.cs
+++ b/src/coreclr/tools/aot/crossgen2/Program.cs
@@ -78,7 +78,8 @@ public int Run()
 
             (TargetArchitecture targetArchitecture, TargetOS targetOS, TargetAbi targetAbi) =
                 Helpers.GetTargetSpec(Get(_command.TargetArchitecture), Get(_command.TargetOS));
-            bool targetAllowsRuntimeCodeGeneration = GetTargetAllowsRuntimeCodeGeneration(targetOS, targetArchitecture);
+            bool targetAllowsRuntimeCodeGeneration = Get(_command.TargetAllowsRuntimeCodeGeneration)
+                ?? GetTargetAllowsRuntimeCodeGeneration(targetOS, targetArchitecture);
 
             // Crossgen2 is partial AOT and its pre-compiled methods can be thrown away at runtime if
             // they mismatch in required ISAs or computed layouts of structs. On targets that allow
diff --git a/src/coreclr/tools/aot/crossgen2/Properties/Resources.resx b/src/coreclr/tools/aot/crossgen2/Properties/Resources.resx
index 8a34770d35e215..1253393d39490b 100644
--- a/src/coreclr/tools/aot/crossgen2/Properties/Resources.resx
+++ b/src/coreclr/tools/aot/crossgen2/Properties/Resources.resx
@@ -282,6 +282,9 @@
   <data name="TargetArchOption" xml:space="preserve">
     <value>Target architecture for cross compilation</value>
   </data>
+  <data name="TargetAllowsRuntimeCodeGenerationOption" xml:space="preserve">
+    <value>Whether the target supports runtime code generation</value>
+  </data>
   <data name="TargetOSOption" xml:space="preserve">
     <value>Target OS for cross compilation</value>
   </data>

From 438e5ac83137b872235fc6ae2f440ed5def134f3 Mon Sep 17 00:00:00 2001
From: Vlad Brezae <brezaevlad@gmail.com>
Date: Sat, 29 Aug 2026 10:26:27 +0300
Subject: [PATCH 2/2] fix description

---
 src/coreclr/tools/aot/crossgen2/Properties/Resources.resx | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/coreclr/tools/aot/crossgen2/Properties/Resources.resx b/src/coreclr/tools/aot/crossgen2/Properties/Resources.resx
index 1253393d39490b..f07167b26a351f 100644
--- a/src/coreclr/tools/aot/crossgen2/Properties/Resources.resx
+++ b/src/coreclr/tools/aot/crossgen2/Properties/Resources.resx
@@ -283,7 +283,7 @@
     <value>Target architecture for cross compilation</value>
   </data>
   <data name="TargetAllowsRuntimeCodeGenerationOption" xml:space="preserve">
-    <value>Whether the target supports runtime code generation</value>
+    <value>Override whether the target supports runtime code generation</value>
   </data>
   <data name="TargetOSOption" xml:space="preserve">
     <value>Target OS for cross compilation</value>