From a35e9efabe01cfb4c46c2b8307493e21d1cf0415 Mon Sep 17 00:00:00 2001
From: Radek Doulik <radekdoulik@gmail.com>
Date: Mon, 28 Dec 2020 16:43:54 +0100
Subject: [PATCH] [illink] Do not preserve GeneratedEnumAttribute

Context: https://github.com/xamarin/xamarin-android/issues/5167

The attribute itself doesn't need to be preserved.

I didn't find any usage of the attribute instances during runtime, so
this change removes them during linking.

apk size comparison, BuildReleaseArm64False test:

    > apkdiff -f -e dll$ before.apk after.apk
    Size difference in bytes ([*1] apk1 only, [*2] apk2 only):
      -          39 assemblies/Mono.Android.dll
        +         132 Resource Android.ILLink.ILLink.LinkAttributes.xml
        -             Type Android.Runtime.GeneratedEnumAttribute
    Summary:
      -          39 Assemblies -0.01% (of 749,078)

Note that the attribute instances removal doesn't work yet, we need
net6 illink for that.
---
 .../PreserveLists/Mono.Android.xml                             | 1 -
 src/Mono.Android/ILLink/ILLink.LinkAttributes.xml              | 3 +++
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/Microsoft.Android.Sdk.ILLink/PreserveLists/Mono.Android.xml b/src/Microsoft.Android.Sdk.ILLink/PreserveLists/Mono.Android.xml
index 3958d28e331..8f593a2044f 100644
--- a/src/Microsoft.Android.Sdk.ILLink/PreserveLists/Mono.Android.xml
+++ b/src/Microsoft.Android.Sdk.ILLink/PreserveLists/Mono.Android.xml
@@ -3,7 +3,6 @@
 	<assembly fullname="Mono.Android">
 		<type fullname="Android.Runtime.AnnotationAttribute" />
 		<type fullname="Android.Runtime.GeneratedDummyHost" />
-		<type fullname="Android.Runtime.GeneratedEnumAttribute" />
 		<type fullname="Android.Runtime.IJavaObject" />
 		<type fullname="Android.Runtime.InputStreamAdapter" />
 		<type fullname="Android.Runtime.InputStreamInvoker" />
diff --git a/src/Mono.Android/ILLink/ILLink.LinkAttributes.xml b/src/Mono.Android/ILLink/ILLink.LinkAttributes.xml
index 0f8c426864d..ebafd5160a3 100644
--- a/src/Mono.Android/ILLink/ILLink.LinkAttributes.xml
+++ b/src/Mono.Android/ILLink/ILLink.LinkAttributes.xml
@@ -6,5 +6,8 @@
     <type fullname="Android.Runtime.IntDefinitionAttribute">
       <attribute internal="RemoveAttributeInstances" />
     </type>
+    <type fullname="Android.Runtime.GeneratedEnumAttribute">
+      <attribute internal="RemoveAttributeInstances" />
+    </type>
   </assembly>
 </linker>