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[dotnet-linker] Use [DynamicDependency] attributes instead of manual marking when optimizing generated code. #24979

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Merged
rolfbjarne merged 6 commits into from
Apr 1, 2026
Merged

[dotnet-linker] Use [DynamicDependency] attributes instead of manual marking when optimizing generated code. #24979

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723f6c9
[dotnet-linker] Use [DynamicDependency] attributes instead of manual …
rolfbjarne Mar 19, 2026
56a5d3c
Grammar
rolfbjarne Mar 31, 2026
442da75
comments
rolfbjarne Mar 31, 2026
4c459e1
regen
rolfbjarne Mar 31, 2026
6277428
[tests] Update expected sizes.
rolfbjarne Mar 31, 2026
fd74549
Remove old tests.
rolfbjarne Apr 1, 2026
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4 changes: 3 additions & 1 deletion dotnet/targets/Xamarin.Shared.Sdk.targets
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Expand Up @@ -550,6 +550,7 @@
<_UseDynamicDependenciesForProtocolPreservation Condition="'$(_UseDynamicDependenciesForProtocolPreservation)' == ''">$(_UseDynamicDependenciesInsteadOfMarking)</_UseDynamicDependenciesForProtocolPreservation>
<_UseDynamicDependenciesForSmartEnumPreservation Condition="'$(_UseDynamicDependenciesForSmartEnumPreservation)' == ''">$(_UseDynamicDependenciesInsteadOfMarking)</_UseDynamicDependenciesForSmartEnumPreservation>
<_UseDynamicDependenciesForBlockCodePreservation Condition="'$(_UseDynamicDependenciesForBlockCodePreservation)' == ''">$(_UseDynamicDependenciesInsteadOfMarking)</_UseDynamicDependenciesForBlockCodePreservation>
<_UseDynamicDependenciesForGeneratedCodeOptimizations Condition="'$(_UseDynamicDependenciesForGeneratedCodeOptimizations)' == ''">$(_UseDynamicDependenciesInsteadOfMarking)</_UseDynamicDependenciesForGeneratedCodeOptimizations>
</PropertyGroup>

<PropertyGroup>
Expand Down Expand Up @@ -754,6 +755,7 @@
<_TrimmerCustomSteps Include="$(_AdditionalTaskAssembly)" BeforeStep="MarkStep" Type="Xamarin.Linker.PreserveProtocolsStep" Condition="'$(_AreAnyAssembliesTrimmed)' == 'true' And '$(_UseDynamicDependenciesForProtocolPreservation)' == 'true'" />
<_TrimmerCustomSteps Include="$(_AdditionalTaskAssembly)" BeforeStep="MarkStep" Type="Xamarin.Linker.Steps.PreserveSmartEnumConversionsStep" Condition="'$(_AreAnyAssembliesTrimmed)' == 'true' And '$(_UseDynamicDependenciesForSmartEnumPreservation)' == 'true'" />
<_TrimmerCustomSteps Include="$(_AdditionalTaskAssembly)" BeforeStep="MarkStep" Type="Xamarin.Linker.Steps.PreserveBlockCodeStep" Condition="'$(_AreAnyAssembliesTrimmed)' == 'true' And '$(_UseDynamicDependenciesForBlockCodePreservation)' == 'true'" />
<_TrimmerCustomSteps Include="$(_AdditionalTaskAssembly)" BeforeStep="MarkStep" Type="Xamarin.Linker.Steps.OptimizeGeneratedCodeStep" Condition="'$(_AreAnyAssembliesTrimmed)' == 'true' And '$(_UseDynamicDependenciesForGeneratedCodeOptimizations)' == 'true'" />
<!-- The final decision to remove/keep the dynamic registrar must be done before the linking step -->
<_TrimmerCustomSteps Include="$(_AdditionalTaskAssembly)" BeforeStep="MarkStep" Type="MonoTouch.Tuner.RegistrarRemovalTrackingStep" />
<!-- TODO: these steps should probably run after mark. -->
Expand All @@ -764,7 +766,7 @@
IMarkHandlers which run during Mark
-->
<_TrimmerCustomSteps Include="$(_AdditionalTaskAssembly)" Condition="'$(_AreAnyAssembliesTrimmed)' == 'true' And '$(_UseDynamicDependenciesForBlockCodePreservation)' != 'true'" Type="Xamarin.Linker.Steps.PreserveBlockCodeHandler" />
<_TrimmerCustomSteps Include="$(_AdditionalTaskAssembly)" Condition="'$(_AreAnyAssembliesTrimmed)' == 'true'" Type="Xamarin.Linker.OptimizeGeneratedCodeHandler" />
<_TrimmerCustomSteps Include="$(_AdditionalTaskAssembly)" Condition="'$(_AreAnyAssembliesTrimmed)' == 'true' And '$(_UseDynamicDependenciesForGeneratedCodeOptimizations)' != 'true'" Type="Xamarin.Linker.OptimizeGeneratedCodeHandler" />
<_TrimmerCustomSteps Include="$(_AdditionalTaskAssembly)" Condition="'$(_AreAnyAssembliesTrimmed)' == 'true'" Type="Xamarin.Linker.BackingFieldDelayHandler" />
<_TrimmerCustomSteps Include="$(_AdditionalTaskAssembly)" Condition="'$(_AreAnyAssembliesTrimmed)' == 'true' And '$(_UseDynamicDependenciesForProtocolPreservation)' != 'true'" Type="Xamarin.Linker.MarkIProtocolHandler" />
<!-- MarkDispatcher substeps will run for all marked assemblies. -->
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2 changes: 1 addition & 1 deletion src/Network/NWWebSocketResponse.cs
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Expand Up @@ -74,7 +74,7 @@ public bool EnumerateAdditionalHeaders (Action<string?, string?> handler)

unsafe {
delegate* unmanaged<IntPtr, IntPtr, IntPtr, void> trampoline = &TrampolineEnumerateHeadersHandler;
using var block = new BlockLiteral (trampoline, handler, typeof (NWWebSocketResponseStatus), nameof (TrampolineEnumerateHeadersHandler));
using var block = new BlockLiteral (trampoline, handler, typeof (NWWebSocketResponse), nameof (TrampolineEnumerateHeadersHandler));
return nw_ws_response_enumerate_additional_headers (GetCheckedHandle (), &block) != 0;
}
}
Expand Down
1 change: 0 additions & 1 deletion tests/dotnet/UnitTests/expected/iOS-MonoVM-interpreter-preservedapis.txt
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Expand Up @@ -647,7 +647,6 @@ Microsoft.iOS.dll:ObjCRuntime.Runtime.GetINativeObject(System.IntPtr, System.Boo
Microsoft.iOS.dll:ObjCRuntime.Runtime.GetINativeObject`1(System.IntPtr, System.Boolean, System.Boolean)
Microsoft.iOS.dll:ObjCRuntime.Runtime.GetINativeObject`1(System.IntPtr, System.Boolean, System.Type, System.Boolean, System.IntPtr, System.RuntimeMethodHandle)
Microsoft.iOS.dll:ObjCRuntime.Runtime.GetINativeObject`1(System.IntPtr, System.Boolean, System.Type, System.Boolean)
Microsoft.iOS.dll:ObjCRuntime.Runtime.GetIsARM64CallingConvention()
Microsoft.iOS.dll:ObjCRuntime.Runtime.GetMethodAndObjectForSelector(System.IntPtr, System.IntPtr, System.SByte, System.IntPtr, System.IntPtr*, System.IntPtr)
Microsoft.iOS.dll:ObjCRuntime.Runtime.GetMethodForSelector(System.IntPtr, System.IntPtr, System.SByte, System.IntPtr)
Microsoft.iOS.dll:ObjCRuntime.Runtime.GetMethodFromToken(System.UInt32)
Expand Down
1 change: 0 additions & 1 deletion tests/dotnet/UnitTests/expected/iOS-MonoVM-preservedapis.txt
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Expand Up @@ -493,7 +493,6 @@ Microsoft.iOS.dll:ObjCRuntime.Runtime.GetINativeObject(System.IntPtr, System.Boo
Microsoft.iOS.dll:ObjCRuntime.Runtime.GetINativeObject`1(System.IntPtr, System.Boolean, System.Boolean)
Microsoft.iOS.dll:ObjCRuntime.Runtime.GetINativeObject`1(System.IntPtr, System.Boolean, System.Type, System.Boolean, System.IntPtr, System.RuntimeMethodHandle)
Microsoft.iOS.dll:ObjCRuntime.Runtime.GetINativeObject`1(System.IntPtr, System.Boolean, System.Type, System.Boolean)
Microsoft.iOS.dll:ObjCRuntime.Runtime.GetIsARM64CallingConvention()
Microsoft.iOS.dll:ObjCRuntime.Runtime.GetMethodFromToken(System.UInt32)
Microsoft.iOS.dll:ObjCRuntime.Runtime.GetNSObject(ObjCRuntime.NativeHandle, System.Boolean)
Microsoft.iOS.dll:ObjCRuntime.Runtime.GetNSObject(System.IntPtr, ObjCRuntime.Runtime/MissingCtorResolution, System.Boolean)
Expand Down
134 changes: 0 additions & 134 deletions tests/linker/link sdk/OptimizeGeneratedCodeTest.cs
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Expand Up @@ -170,139 +170,5 @@ public IntPtr FinallyTestMethod ()
finally_invoked = true;
}
}

[Test]
public void IntPtrSizeTest ()
{
IgnoreIfNotLinkAll ();

var S8methods = new MethodInfo []
{
GetType ().GetMethod (nameof (Size8Test), BindingFlags.NonPublic | BindingFlags.Instance),
GetType ().GetMethod (nameof (Size8Test_Optimizable), BindingFlags.NonPublic | BindingFlags.Instance)
};
var S4methods = new MethodInfo []
{
GetType ().GetMethod (nameof (Size4Test), BindingFlags.NonPublic | BindingFlags.Instance),
GetType ().GetMethod (nameof (Size4Test_Optimizable), BindingFlags.NonPublic | BindingFlags.Instance)
};
MethodInfo [] passingMethods = null;
MethodInfo [] failingMethods = null;
switch (IntPtr.Size) {
case 4:
Size4Test ();
Size4Test_Optimizable ();
Assert.Throws<NUnit.Framework.Internal.NUnitException> (Size8Test, "Size8Test");
Assert.Throws<NUnit.Framework.Internal.NUnitException> (Size8Test_Optimizable, "Size8Test_Optimizable");
passingMethods = S4methods;
failingMethods = S8methods;
break;
case 8:
Size8Test ();
Size8Test_Optimizable ();
Assert.Throws<NUnit.Framework.Internal.NUnitException> (Size4Test, "Size4Test");
Assert.Throws<NUnit.Framework.Internal.NUnitException> (Size4Test_Optimizable, "Size4Test_Optimizable");
passingMethods = S8methods;
failingMethods = S4methods;
break;
default:
Assert.Fail ("Invalid size: {0}", IntPtr.Size);
break;
}

#if !DEBUG
// Verify that the passing method is completely empty (save for nop instructions and a final ret instruction).
// Unfortunately in debug mode csc produces IL sequences the optimizer doesn't understand (a lot of unnecessary instructions),
// which means we can only check this in release mode. Also on device this will probably always pass,
// since we strip assemblies (and the methods will always be empty), but running the test shouldn't hurt.
foreach (var passingMethod in passingMethods) {
IEnumerable<ILInstruction> passingInstructions = new ILReader (passingMethod);
passingInstructions = passingInstructions.Where ((v) => v.OpCode.Name != "nop");
Assert.AreEqual (1, passingInstructions.Count (), "empty body");
}
#else
// Verify that the failing methods are not completely empty (even excluding nop instructions and the final ret instruction).
// This can only be executed in debug mode, because in release mode the IL will be stripped away and the methods will be empty.
foreach (var failingMethod in failingMethods) {
IEnumerable<ILInstruction> failingInstructions = new ILReader (failingMethod);
failingInstructions = failingInstructions.Where ((v) => v.OpCode.Name != "nop");
Assert.That (failingInstructions.Count (), Is.GreaterThan (1), "non-empty body");
}
#endif
}

[CompilerGenerated] // Trigger optimizations
[Foundation.Export ("alsoRequiredForOptimizations")]
void Size8Test ()
{
// Everything in this method should be optimized away (when building for 64-bits)
if (IntPtr.Size != 8)
throw new NUnit.Framework.Internal.NUnitException ("1");
if (IntPtr.Size == 4)
throw new NUnit.Framework.Internal.NUnitException ("2");
if (IntPtr.Size > 8)
throw new NUnit.Framework.Internal.NUnitException ("3");
if (IntPtr.Size < 8)
throw new NUnit.Framework.Internal.NUnitException ("4");
if (IntPtr.Size >= 9)
throw new NUnit.Framework.Internal.NUnitException ("5");
if (IntPtr.Size <= 7)
throw new NUnit.Framework.Internal.NUnitException ("6");
}

[CompilerGenerated] // Trigger optimizations
[Foundation.Export ("alsoRequiredForOptimizations")]
void Size4Test ()
{
// Everything in this method should be optimized away (when building for 32-bits)
if (IntPtr.Size != 4)
throw new NUnit.Framework.Internal.NUnitException ("1");
if (IntPtr.Size == 8)
throw new NUnit.Framework.Internal.NUnitException ("2");
if (IntPtr.Size > 4)
throw new NUnit.Framework.Internal.NUnitException ("3");
if (IntPtr.Size < 4)
throw new NUnit.Framework.Internal.NUnitException ("4");
if (IntPtr.Size >= 5)
throw new NUnit.Framework.Internal.NUnitException ("5");
if (IntPtr.Size <= 3)
throw new NUnit.Framework.Internal.NUnitException ("6");
}

[BindingImplAttribute (BindingImplOptions.Optimizable)]
void Size8Test_Optimizable ()
{
// Everything in this method should be optimized away (when building for 64-bits)
if (IntPtr.Size != 8)
throw new NUnit.Framework.Internal.NUnitException ("1");
if (IntPtr.Size == 4)
throw new NUnit.Framework.Internal.NUnitException ("2");
if (IntPtr.Size > 8)
throw new NUnit.Framework.Internal.NUnitException ("3");
if (IntPtr.Size < 8)
throw new NUnit.Framework.Internal.NUnitException ("4");
if (IntPtr.Size >= 9)
throw new NUnit.Framework.Internal.NUnitException ("5");
if (IntPtr.Size <= 7)
throw new NUnit.Framework.Internal.NUnitException ("6");
}

[BindingImplAttribute (BindingImplOptions.Optimizable)]
void Size4Test_Optimizable ()
{
// Everything in this method should be optimized away (when building for 32-bits)
if (IntPtr.Size != 4)
throw new NUnit.Framework.Internal.NUnitException ("1");
if (IntPtr.Size == 8)
throw new NUnit.Framework.Internal.NUnitException ("2");
if (IntPtr.Size > 4)
throw new NUnit.Framework.Internal.NUnitException ("3");
if (IntPtr.Size < 4)
throw new NUnit.Framework.Internal.NUnitException ("4");
if (IntPtr.Size >= 5)
throw new NUnit.Framework.Internal.NUnitException ("5");
if (IntPtr.Size <= 3)
throw new NUnit.Framework.Internal.NUnitException ("6");
}
}
}
27 changes: 27 additions & 0 deletions tools/common/Target.cs
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Expand Up @@ -507,6 +507,33 @@ static bool IsBoundAssembly (Assembly s)

return false;
}

bool _set_arm64_calling_convention;
bool? _is_arm64_calling_convention;
public bool? InlineIsArm64CallingConventionForCurrentAbi {
get {
if (!_set_arm64_calling_convention) {
if (Optimizations.InlineIsARM64CallingConvention == true) {
// We can usually inline Runtime.InlineIsARM64CallingConvention if the generated code will execute on a single architecture
switch (Abi & Abi.ArchMask) {
case Abi.x86_64:
_is_arm64_calling_convention = false;
break;
case Abi.ARM64:
case Abi.ARM64e:
_is_arm64_calling_convention = true;
break;
default:
LinkContext.Exceptions.Add (Xamarin.Bundler.ErrorHelper.CreateWarning (99, Xamarin.Bundler.Errors.MX0099, $"unknown abi: {Abi}"));
break;
}
}
_set_arm64_calling_convention = true;
}
return _is_arm64_calling_convention;
}
}

#endif // !LEGACY_TOOLS
}
}
38 changes: 38 additions & 0 deletions tools/dotnet-linker/OptimizeGeneratedCodeStep.cs
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@@ -0,0 +1,38 @@
// Copyright (c) Microsoft Corporation.
// Licensed under the MIT License.

using Mono.Cecil;

#nullable enable

namespace Xamarin.Linker.Steps {
public class OptimizeGeneratedCodeStep : AssemblyModifierStep {
protected override string Name { get; } = "Binding Optimizer";
protected override int ErrorCode { get; } = 2020;

OptimizeGeneratedCodeData? data;

protected override bool IsActiveFor (AssemblyDefinition assembly)
{
return OptimizeGeneratedCodeHandler.IsActiveFor (assembly, Configuration.Profile, DerivedLinkContext.Annotations);
}

protected override bool ProcessType (TypeDefinition type)
{
return ProcessMethods (type);
}

protected override bool ProcessMethod (MethodDefinition method)
{
if (data is null) {
data = new OptimizeGeneratedCodeData {
LinkContext = DerivedLinkContext,
InlineIsArm64CallingConvention = App.InlineIsArm64CallingConventionForCurrentAbi,
Optimizations = App.Optimizations,
Device = App.IsDeviceBuild,
};
}
return OptimizeGeneratedCodeHandler.OptimizeMethod (data, method);
}
}
}
12 changes: 2 additions & 10 deletions tools/dotnet-linker/PreserveSmartEnumConversionsStep.cs
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Expand Up @@ -61,18 +61,10 @@ bool Preserve (Tuple<MethodDefinition, MethodDefinition> pair, bool alreadyProce

protected override bool ProcessType (TypeDefinition type)
{
var modified = false;

if (!type.HasMethods)
return modified;

foreach (var method in type.Methods)
modified |= ProcessMethod (method);

return modified;
return base.ProcessMethods (type);
}

bool ProcessMethod (MethodDefinition method)
protected override bool ProcessMethod (MethodDefinition method)
{
static bool IsPropertyMethod (MethodDefinition method)
{
Expand Down
16 changes: 16 additions & 0 deletions tools/dotnet-linker/Steps/AssemblyModifierStep.cs
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Expand Up @@ -35,6 +35,11 @@ protected virtual bool ProcessType (TypeDefinition type)
return false;
}

protected virtual bool ProcessMethod (MethodDefinition method)
{
return false;
}

bool ProcessTypeImpl (TypeDefinition type)
{
var modified = ProcessType (type);
Expand All @@ -44,4 +49,15 @@ bool ProcessTypeImpl (TypeDefinition type)
}
return modified;
}

protected bool ProcessMethods (TypeDefinition type)
{
if (!type.HasMethods)
return false;

var modified = false;
foreach (var method in type.Methods)
modified |= ProcessMethod (method);
return modified;
}
}
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