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[TrimmableTypeMap] Improve trimmable typemap framework roots #11498

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Merged
jonathanpeppers merged 9 commits into from
May 28, 2026
Merged

[TrimmableTypeMap] Improve trimmable typemap framework roots #11498

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18d6f0f
Compare trimmable typemap APK contents
simonrozsival May 14, 2026
98223cb
Enable R8 shrinking for trimmable typemap comparison
simonrozsival May 14, 2026
91d61f7
Pass per-assembly typemap entries to ILLink
simonrozsival May 14, 2026
657165f
Refine trimmable typemap framework roots
simonrozsival May 14, 2026
9ec7a22
Support DynamicCodeSupport=false with trimmable typemaps
simonrozsival May 20, 2026
253a264
Keep trimming PR focused on product improvements
simonrozsival May 26, 2026
70660e3
Address PR review feedback for trimmable typemap
Copilot May 26, 2026
2c25481
Fix trimmable typemap startup roots
simonrozsival May 26, 2026
1399a77
Address trimmable typemap review feedback
simonrozsival May 28, 2026
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44 changes: 34 additions & 10 deletions src/Microsoft.Android.Sdk.TrimmableTypeMap/Generator/RootTypeMapAssemblyGenerator.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -135,7 +135,7 @@ public void Generate (IReadOnlyList<string> perAssemblyTypeMapNames, bool useSha
pe.EmitIgnoresAccessChecksToAttribute (accessTargets);

// Emit TypeMapLoader class with Initialize() method
EmitTypeMapLoader (pe, anchorTypeHandle, perAssemblyTypeMapNames, useSharedTypemapUniverse, maxArrayRank);
EmitTypeMapLoader (pe, anchorTypeHandle, perAssemblyTypeMapNames, useSharedTypemapUniverse, maxArrayRank, assemblyName);

pe.WritePE (stream);
}
Expand Down Expand Up @@ -201,7 +201,7 @@ static void EmitAssemblyTargetAttribute (PEAssemblyBuilder pe, MemberReferenceHa
pe.Metadata.AddCustomAttribute (EntityHandle.AssemblyDefinition, ctorRef, blobHandle);
}

static void EmitTypeMapLoader (PEAssemblyBuilder pe, EntityHandle anchorTypeHandle, IReadOnlyList<string> perAssemblyTypeMapNames, bool useSharedTypemapUniverse, int maxArrayRank)
static void EmitTypeMapLoader (PEAssemblyBuilder pe, EntityHandle anchorTypeHandle, IReadOnlyList<string> perAssemblyTypeMapNames, bool useSharedTypemapUniverse, int maxArrayRank, string assemblyName)
{
var metadata = pe.Metadata;

Expand Down Expand Up @@ -243,21 +243,21 @@ static void EmitTypeMapLoader (PEAssemblyBuilder pe, EntityHandle anchorTypeHand
if (maxArrayRank > 0) {
var initializeRef = AddInitializeSingleWithArraysRef (pe, trimmableTypeMapRef, iReadOnlyDictOpenRef, systemTypeRef);
EmitInitializeWithSingleTypeMap (pe, anchorTypeHandle, getExternalMemberRef, getProxyMemberRef,
initializeRef, externalDictTypeSpec, externalDictArrayTypeSpec, perAssemblyTypeMapNames, maxArrayRank);
initializeRef, externalDictTypeSpec, externalDictArrayTypeSpec, perAssemblyTypeMapNames, maxArrayRank, assemblyName);
} else {
var initializeRef = AddInitializeSingleNoArraysRef (pe, trimmableTypeMapRef, iReadOnlyDictOpenRef, systemTypeRef);
EmitInitializeWithSingleTypeMapNoArrays (pe, anchorTypeHandle, getExternalMemberRef, getProxyMemberRef, initializeRef);
EmitInitializeWithSingleTypeMapNoArrays (pe, anchorTypeHandle, getExternalMemberRef, getProxyMemberRef, initializeRef, assemblyName);
}
} else {
var proxyDictTypeSpec = MakeIReadOnlyDictTypeSpec (pe, iReadOnlyDictOpenRef, systemTypeRef, keyIsString: false);
if (maxArrayRank > 0) {
var initializeRef = AddInitializeAggregateWithArraysRef (pe, trimmableTypeMapRef, iReadOnlyDictOpenRef, systemTypeRef);
EmitInitializeWithAggregateTypeMap (pe, perAssemblyTypeMapNames, getExternalMemberRef, getProxyMemberRef,
initializeRef, externalDictTypeSpec, proxyDictTypeSpec, externalDictArrayTypeSpec, iReadOnlyDictOpenRef, systemTypeRef, maxArrayRank);
initializeRef, externalDictTypeSpec, proxyDictTypeSpec, externalDictArrayTypeSpec, iReadOnlyDictOpenRef, systemTypeRef, maxArrayRank, assemblyName);
} else {
var initializeRef = AddInitializeAggregateNoArraysRef (pe, trimmableTypeMapRef, iReadOnlyDictOpenRef, systemTypeRef);
EmitInitializeWithAggregateTypeMapNoArrays (pe, perAssemblyTypeMapNames, getExternalMemberRef, getProxyMemberRef,
initializeRef, externalDictTypeSpec, proxyDictTypeSpec, iReadOnlyDictOpenRef, systemTypeRef);
initializeRef, externalDictTypeSpec, proxyDictTypeSpec, iReadOnlyDictOpenRef, systemTypeRef, assemblyName);
}
}
}
Expand All @@ -274,7 +274,8 @@ static void EmitInitializeWithAggregateTypeMap (PEAssemblyBuilder pe,
TypeSpecificationHandle externalDictTypeSpec, TypeSpecificationHandle proxyDictTypeSpec,
TypeSpecificationHandle externalDictArrayTypeSpec,
TypeReferenceHandle iReadOnlyDictOpenRef, TypeReferenceHandle systemTypeRef,
int maxArrayRank)
int maxArrayRank,
string assemblyName)
{
var count = perAssemblyTypeMapNames.Count;

Expand All @@ -292,6 +293,7 @@ static void EmitInitializeWithAggregateTypeMap (PEAssemblyBuilder pe,
MethodAttributes.Public | MethodAttributes.Static | MethodAttributes.HideBySig,
sig => sig.MethodSignature ().Parameters (0, rt => rt.Void (), p => { }),
encoder => {
EmitSetTypeMappingEntryAssembly (pe, encoder, assemblyName);
// var typeMaps = new IReadOnlyDictionary<string, Type>[N]; (loc 0)
EmitNewArrayLocal (encoder, count, externalDictTypeSpec, slot: 0);
EmitFillArrayLocal (encoder, count, getExternalSpecs, slot: 0);
Expand Down Expand Up @@ -345,7 +347,8 @@ static void EmitInitializeWithAggregateTypeMapNoArrays (PEAssemblyBuilder pe,
MemberReferenceHandle getExternalMemberRef, MemberReferenceHandle getProxyMemberRef,
MemberReferenceHandle initializeRef,
TypeSpecificationHandle externalDictTypeSpec, TypeSpecificationHandle proxyDictTypeSpec,
TypeReferenceHandle iReadOnlyDictOpenRef, TypeReferenceHandle systemTypeRef)
TypeReferenceHandle iReadOnlyDictOpenRef, TypeReferenceHandle systemTypeRef,
string assemblyName)
{
var count = perAssemblyTypeMapNames.Count;

Expand All @@ -363,6 +366,7 @@ static void EmitInitializeWithAggregateTypeMapNoArrays (PEAssemblyBuilder pe,
MethodAttributes.Public | MethodAttributes.Static | MethodAttributes.HideBySig,
sig => sig.MethodSignature ().Parameters (0, rt => rt.Void (), p => { }),
encoder => {
EmitSetTypeMappingEntryAssembly (pe, encoder, assemblyName);
EmitNewArrayLocal (encoder, count, externalDictTypeSpec, slot: 0);
EmitFillArrayLocal (encoder, count, getExternalSpecs, slot: 0);

Expand Down Expand Up @@ -432,7 +436,8 @@ static void EmitInitializeWithSingleTypeMap (PEAssemblyBuilder pe, EntityHandle
MemberReferenceHandle initializeRef,
TypeSpecificationHandle externalDictTypeSpec, TypeSpecificationHandle externalDictArrayTypeSpec,
IReadOnlyList<string> perAssemblyTypeMapNames,
int maxArrayRank)
int maxArrayRank,
string assemblyName)
{
var getExternalSpec = MakeGenericMethodSpec (pe, getExternalMemberRef, anchorTypeHandle);
var getProxySpec = MakeGenericMethodSpec (pe, getProxyMemberRef, anchorTypeHandle);
Expand All @@ -441,6 +446,7 @@ static void EmitInitializeWithSingleTypeMap (PEAssemblyBuilder pe, EntityHandle
MethodAttributes.Public | MethodAttributes.Static | MethodAttributes.HideBySig,
sig => sig.MethodSignature ().Parameters (0, rt => rt.Void (), p => { }),
encoder => {
EmitSetTypeMappingEntryAssembly (pe, encoder, assemblyName);
// TrimmableTypeMap.Initialize(GetExternal<JL.Object>(), GetProxy<JL.Object>(), arrayMapsByAssemblyAndRank-or-null)
encoder.Call (getExternalSpec, parameterCount: 0, returnsValue: true);
encoder.Call (getProxySpec, parameterCount: 0, returnsValue: true);
Expand All @@ -456,7 +462,8 @@ static void EmitInitializeWithSingleTypeMap (PEAssemblyBuilder pe, EntityHandle
/// </summary>
static void EmitInitializeWithSingleTypeMapNoArrays (PEAssemblyBuilder pe, EntityHandle anchorTypeHandle,
MemberReferenceHandle getExternalMemberRef, MemberReferenceHandle getProxyMemberRef,
MemberReferenceHandle initializeRef)
MemberReferenceHandle initializeRef,
string assemblyName)
{
var getExternalSpec = MakeGenericMethodSpec (pe, getExternalMemberRef, anchorTypeHandle);
var getProxySpec = MakeGenericMethodSpec (pe, getProxyMemberRef, anchorTypeHandle);
Expand All @@ -465,6 +472,7 @@ static void EmitInitializeWithSingleTypeMapNoArrays (PEAssemblyBuilder pe, Entit
MethodAttributes.Public | MethodAttributes.Static | MethodAttributes.HideBySig,
sig => sig.MethodSignature ().Parameters (0, rt => rt.Void (), p => { }),
encoder => {
EmitSetTypeMappingEntryAssembly (pe, encoder, assemblyName);
encoder.Call (getExternalSpec, parameterCount: 0, returnsValue: true);
encoder.Call (getProxySpec, parameterCount: 0, returnsValue: true);
encoder.Call (initializeRef, parameterCount: 2);
Expand All @@ -486,6 +494,22 @@ static MemberReferenceHandle AddInitializeSingleNoArraysRef (PEAssemblyBuilder p
pe.Metadata.GetOrAddString ("Initialize"), pe.Metadata.GetOrAddBlob (blob));
}

static void EmitSetTypeMappingEntryAssembly (PEAssemblyBuilder pe, TrackedInstructionEncoder encoder, string assemblyName)
{
var appContextRef = pe.Metadata.AddTypeReference (pe.SystemRuntimeRef,
pe.Metadata.GetOrAddString ("System"), pe.Metadata.GetOrAddString ("AppContext"));
var setDataRef = pe.AddMemberRef (appContextRef, "SetData",
sig => sig.MethodSignature ().Parameters (2,
rt => rt.Void (),
p => {
p.AddParameter ().Type ().String ();
p.AddParameter ().Type ().Object ();
}));
encoder.LoadString (pe.Metadata.GetOrAddUserString ("System.Runtime.InteropServices.TypeMappingEntryAssembly"));
encoder.LoadString (pe.Metadata.GetOrAddUserString (assemblyName));
encoder.Call (setDataRef, parameterCount: 2);
}

/// <summary>MemberRef for <c>TrimmableTypeMap.Initialize(typeMap, proxyMap, arrayMapsByAssemblyAndRank[][])</c>.</summary>
static MemberReferenceHandle AddInitializeSingleWithArraysRef (PEAssemblyBuilder pe, TypeReferenceHandle trimmableTypeMapRef,
TypeReferenceHandle iReadOnlyDictOpenRef, TypeReferenceHandle systemTypeRef)
Expand Down
4 changes: 3 additions & 1 deletion src/Microsoft.Android.Sdk.TrimmableTypeMap/Scanner/JavaPeerInfo.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -44,7 +44,9 @@ public sealed record JavaPeerInfo
public required string AssemblyName { get; init; }

/// <summary>
/// True when the type belongs to a framework assembly.
/// True when the type belongs to a framework assembly supplied by the Android SDK.
/// Framework ACWs are generated by the SDK and can be trimmed like bindings unless
/// another rule explicitly roots them.
/// </summary>
public bool IsFrameworkAssembly { get; init; }

Expand Down
25 changes: 24 additions & 1 deletion ...sks/Microsoft.Android.Sdk/targets/Microsoft.Android.Sdk.TypeMap.Trimmable.CoreCLR.targets
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Original file line number Diff line number Diff line change
Expand Up @@ -5,13 +5,18 @@
<_TrimmableRuntimeProviderJavaName Condition=" '$(_TrimmableRuntimeProviderJavaName)' == '' ">mono.MonoRuntimeProvider</_TrimmableRuntimeProviderJavaName>
</PropertyGroup>

<PropertyGroup>
<_GenerateProguardAfterTargets Condition=" '$(_GenerateProguardAfterTargets)' == '' ">ILLink</_GenerateProguardAfterTargets>
</PropertyGroup>

<!-- Add TypeMap DLLs to ILLink input. ILLink natively understands TypeMapAttribute<T>. -->
<Target Name="_AddTrimmableTypeMapToLinker"
BeforeTargets="PrepareForILLink;_RunILLink"
DependsOnTargets="_GenerateTrimmableTypeMap">
<ItemGroup>
<ManagedAssemblyToLink Include="$(_TypeMapOutputDirectory)*.dll">
<DestinationSubPath>%(Filename)%(Extension)</DestinationSubPath>
<IsTrimmable>true</IsTrimmable>
</ManagedAssemblyToLink>
</ItemGroup>
</Target>
Expand All @@ -21,10 +26,28 @@
BeforeTargets="PrepareForILLink;_RunILLink"
DependsOnTargets="_GenerateTrimmableTypeMap">
<PropertyGroup>
<_ExtraTrimmerArgs>--typemap-entry-assembly $(_TypeMapAssemblyName) $(_ExtraTrimmerArgs)</_ExtraTrimmerArgs>
<_ExtraTrimmerArgs>$(_ExtraTrimmerArgs) --typemap-entry-assembly "$(_TypeMapAssemblyName)"</_ExtraTrimmerArgs>
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</PropertyGroup>
</Target>

<Target Name="_PrepareLinkedAssembliesForProguard"
AfterTargets="$(_GenerateProguardAfterTargets)"
Condition=" '$(PublishTrimmed)' == 'true' and '$(_ProguardProjectConfiguration)' != '' ">
<ItemGroup>
<_LinkedAssemblyForProguard Include="@(ResolvedFileToPublish)" Condition=" '%(Extension)' == '.dll' " />
</ItemGroup>
</Target>

<Target Name="_GenerateProguardConfiguration"
AfterTargets="_PrepareLinkedAssembliesForProguard"
Condition=" '$(PublishTrimmed)' == 'true' and '$(_ProguardProjectConfiguration)' != '' "
Inputs="@(_LinkedAssemblyForProguard)"
Outputs="$(_ProguardProjectConfiguration)">
<GenerateProguardConfiguration
LinkedAssemblies="@(_LinkedAssemblyForProguard)"
OutputFile="$(_ProguardProjectConfiguration)" />
</Target>

<!-- Add linked TypeMap DLLs to the normal publish assembly pipeline. The SDK R2R
target only compiles ResolvedFileToPublish items with PostprocessAssembly=true. -->
<Target Name="_AddTrimmableTypeMapToResolvedFileToPublish"
Expand Down
8 changes: 5 additions & 3 deletions ...Build.Tasks/Microsoft.Android.Sdk/targets/Microsoft.Android.Sdk.TypeMap.Trimmable.targets
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Original file line number Diff line number Diff line change
Expand Up @@ -4,6 +4,7 @@
<UsingTask TaskName="Xamarin.Android.Tasks.GenerateTrimmableTypeMap" AssemblyFile="$(_XamarinAndroidBuildTasksAssembly)" />
<UsingTask TaskName="Xamarin.Android.Tasks.GenerateEmptyTypemapStub" AssemblyFile="$(_XamarinAndroidBuildTasksAssembly)" />
<UsingTask TaskName="Xamarin.Android.Tasks.GenerateNativeAotBootstrapSources" AssemblyFile="$(_XamarinAndroidBuildTasksAssembly)" />
<UsingTask TaskName="Xamarin.Android.Tasks.GenerateProguardConfiguration" AssemblyFile="$(_XamarinAndroidBuildTasksAssembly)" />

<Import Project="$(MSBuildThisFileDirectory)Microsoft.Android.Sdk.TypeMap.Trimmable.CoreCLR.targets"
Condition=" '$(_AndroidRuntime)' == 'CoreCLR' " />
Expand All @@ -23,10 +24,10 @@
<_TypeMapOutputDirectory>$(_TypeMapBaseOutputDir)typemap/</_TypeMapOutputDirectory>
<_TypeMapJavaOutputDirectory>$(_TypeMapBaseOutputDir)typemap/java</_TypeMapJavaOutputDirectory>
<_TypeMapAssembliesListFile>$(_TypeMapOutputDirectory)typemap-assemblies.txt</_TypeMapAssembliesListFile>
<!-- Max array rank for __ArrayMapRank{N} sentinel emission. Defaults to 3 for NativeAOT
(PublishAot=true, dynamic code is unavailable, so array creation uses the typemap path);
<!-- Max array rank for __ArrayMapRank{N} sentinel emission. Defaults to 3 when
dynamic code is unavailable, so array creation uses the typemap path;
defaults to 0 otherwise, where dynamic code can use Array.CreateInstance directly. -->
<_AndroidTrimmableTypeMapMaxArrayRank Condition=" '$(_AndroidTrimmableTypeMapMaxArrayRank)' == '' and '$(PublishAot)' == 'true' ">3</_AndroidTrimmableTypeMapMaxArrayRank>
<_AndroidTrimmableTypeMapMaxArrayRank Condition=" '$(_AndroidTrimmableTypeMapMaxArrayRank)' == '' and ('$(PublishAot)' == 'true' or '$(DynamicCodeSupport)' == 'false') ">3</_AndroidTrimmableTypeMapMaxArrayRank>
<_AndroidTrimmableTypeMapMaxArrayRank Condition=" '$(_AndroidTrimmableTypeMapMaxArrayRank)' == '' ">0</_AndroidTrimmableTypeMapMaxArrayRank>
<IncrementalCleanDependsOn>
_RecordTrimmableTypeMapFileWrites;
Expand Down Expand Up @@ -88,6 +89,7 @@
<GenerateTrimmableTypeMap
ResolvedAssemblies="@(_TypeMapInputAssemblies)"
ResolvedFrameworkAssemblies="@(ResolvedFrameworkAssemblies)"
FrameworkAssemblyNames="@(ResolvedFrameworkAssemblies->'%(Filename)')"
OutputDirectory="$(_TypeMapOutputDirectory)"
JavaSourceOutputDirectory="$(_TypeMapJavaOutputDirectory)"
TargetFrameworkVersion="$(TargetFrameworkVersion)"
Expand Down
12 changes: 11 additions & 1 deletion src/Xamarin.Android.Build.Tasks/Tasks/GenerateTrimmableTypeMap.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -15,6 +15,12 @@ namespace Xamarin.Android.Tasks;

public class GenerateTrimmableTypeMap : AndroidTask
{
static readonly string [] DefaultFrameworkAssemblyNames = [
"Java.Interop",
"Mono.Android",
"Mono.Android.Runtime",
];

sealed class MSBuildTrimmableTypeMapLogger (TaskLoggingHelper log) : ITrimmableTypeMapLogger
{
public void LogNoJavaPeerTypesFound () =>
Expand Down Expand Up @@ -46,6 +52,7 @@ public void LogJniAddNativeMethodRegistrationAttributeError (string managedTypeN
[Required]
public ITaskItem [] ResolvedAssemblies { get; set; } = [];
public ITaskItem [] ResolvedFrameworkAssemblies { get; set; } = [];
public string [] FrameworkAssemblyNames { get; set; } = [];
[Required]
public string OutputDirectory { get; set; } = "";
[Required]
Expand Down Expand Up @@ -105,7 +112,10 @@ public override bool RunTask ()
Path: g.Key,
IsFrameworkAssembly: frameworkAssemblyPaths.Contains (g.Key) || g.Any (IsFrameworkAssemblyItem)))
.ToList ();
var frameworkAssemblyNames = new HashSet<string> (StringComparer.OrdinalIgnoreCase);
var frameworkAssemblyNames = new HashSet<string> (DefaultFrameworkAssemblyNames, StringComparer.OrdinalIgnoreCase);
foreach (var assemblyName in FrameworkAssemblyNames) {
frameworkAssemblyNames.Add (assemblyName);
}

Directory.CreateDirectory (OutputDirectory);
Directory.CreateDirectory (JavaSourceOutputDirectory);
Expand Down
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