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[TrimmableTypeMap] Generate NativeAOT ProGuard rules from DGML - #11449
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simonrozsival merged 14 commits intoMay 29, 2026
Merged
[TrimmableTypeMap] Generate NativeAOT ProGuard rules from DGML#11449simonrozsival merged 14 commits into
simonrozsival merged 14 commits into
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Pull request overview
This PR adds a trimmable NativeAOT + R8 workflow where ProGuard/R8 keep rules are generated from NativeAOT ILC DGML scan output intersected with acw-map.txt, allowing R8 to remove unused generated Java wrappers and significantly reduce classes.dex size.
Changes:
- Generate NativeAOT-specific ProGuard rules after
IlcCompilefrom*.scan.dgml.xml+acw-map.txt, and adjust R8 configuration generation to avoid broad keep rules in this mode. - Extend the trimmable typemap pipeline to classify framework peers, selectively emit array typemap entries only when referenced from non-framework assemblies, and persist the list of generated typemap assemblies to stabilize incremental builds.
- Add runtime feature plumbing for
IsNativeAotRuntimeand adjust NativeAOT JNI initialization ordering/inputs to provide required Java peer marker classes.
Reviewed changes
Copilot reviewed 32 out of 32 changed files in this pull request and generated 3 comments.
Show a summary per file
| File | Description |
|---|---|
| tests/Microsoft.Android.Sdk.TrimmableTypeMap.Tests/TestFixtures/TestTypes.cs | Adds framework-like SSL and network peer types to exercise framework JCW/peer scanning scenarios. |
| tests/Microsoft.Android.Sdk.TrimmableTypeMap.Tests/Scanner/JavaPeerScannerTests.cs | Adds test coverage for framework peer marking and array-entry emission behavior. |
| tests/Microsoft.Android.Sdk.TrimmableTypeMap.Tests/Generator/TypeMapModelBuilderTests.cs | Tests framework ACW conditionality and array-entry emission rules; updates anchor visibility assertions. |
| tests/Microsoft.Android.Sdk.TrimmableTypeMap.Tests/Generator/TrimmableTypeMapGeneratorTests.cs | Verifies generator can emit expected framework JCW Java sources. |
| src/Xamarin.Android.Build.Tasks/Xamarin.Android.D8.targets | Plumbs UseTrimmableNativeAotProguardConfiguration into the R8 task invocation. |
| src/Xamarin.Android.Build.Tasks/Xamarin.Android.Common.targets | Adds _AndroidTrimmableTypeMapMaxArrayRank to the property cache for incremental invalidation. |
| src/Xamarin.Android.Build.Tasks/Tests/Xamarin.ProjectTools/Resources/Base/BuildReleaseArm64XFormsDotNet.MonoVM.apkdesc | Updates expected APK contents/sizes after build output changes. |
| src/Xamarin.Android.Build.Tasks/Tests/Xamarin.ProjectTools/Resources/Base/BuildReleaseArm64SimpleDotNet.MonoVM.apkdesc | Updates expected APK contents/sizes after build output changes. |
| src/Xamarin.Android.Build.Tasks/Tests/Xamarin.Android.Build.Tests/TrimmableTypeMapBuildTests.cs | Adds incremental/build validation for array-rank changes and NativeAOT/CoreCLR typemap behaviors. |
| src/Xamarin.Android.Build.Tasks/Tests/Xamarin.Android.Build.Tests/Tasks/GenerateTrimmableTypeMapTests.cs | Adds task-level tests for generated typemap assembly list file and framework JCW emission. |
| src/Xamarin.Android.Build.Tasks/Tasks/R8.cs | Adds a trimmable NativeAOT mode that alters generated ProGuard config inputs and common rules. |
| src/Xamarin.Android.Build.Tasks/Tasks/GenerateTrimmableTypeMap.cs | Adds framework assembly classification and writes a generated-assemblies list file. |
| src/Xamarin.Android.Build.Tasks/Tasks/GenerateProguardConfiguration.cs | Adds DGML+ACW-map based ProGuard rule generation for NativeAOT trimmable builds. |
| src/Xamarin.Android.Build.Tasks/Microsoft.Android.Sdk/targets/Microsoft.Android.Sdk.TypeMap.Trimmable.targets | Persists typemap-generated assembly list and uses it for downstream item population/incremental correctness. |
| src/Xamarin.Android.Build.Tasks/Microsoft.Android.Sdk/targets/Microsoft.Android.Sdk.TypeMap.Trimmable.NativeAOT.targets | Hooks DGML-based ProGuard rule generation and adjusts ILC inputs for trimmable typemap NativeAOT. |
| src/Xamarin.Android.Build.Tasks/Microsoft.Android.Sdk/targets/Microsoft.Android.Sdk.TypeMap.LlvmIr.targets | Adds opt-out switch to skip linked-assembly ProGuard configuration generation when replaced by DGML flow. |
| src/Xamarin.Android.Build.Tasks/Microsoft.Android.Sdk/targets/Microsoft.Android.Sdk.NativeAOT.targets | Enables DGML generation for R8 builds, configures skip/alternate ProGuard generation, and sets runtime feature. |
| src/Xamarin.Android.Build.Tasks/Microsoft.Android.Sdk/targets/Microsoft.Android.Sdk.MonoVM.targets | Sets IsNativeAotRuntime=false runtime feature for MonoVM. |
| src/Xamarin.Android.Build.Tasks/Microsoft.Android.Sdk/targets/Microsoft.Android.Sdk.CoreCLR.targets | Sets IsNativeAotRuntime=false runtime feature for CoreCLR. |
| src/native/nativeaot/host/host.cc | Ensures NativeAOT host provides global refs for required Java peer marker classes during init. |
| src/Mono.Android/Microsoft.Android.Runtime/RuntimeFeature.cs | Adds RuntimeFeature.IsNativeAotRuntime AppContext switch. |
| src/Mono.Android/Android.Runtime/JNIEnvInit.cs | Refactors JNI initialization to share common state init and add NativeAOT-specific runtime initialization entrypoint. |
| src/Mono.Android/Android.Runtime/JNIEnv.cs | Routes unhandled exception propagation consistently for NativeAOT. |
| src/Mono.Android/Android.Runtime/AndroidRuntimeInternal.cs | Treats NativeAOT unhandled exceptions like the CoreCLR path. |
| src/Microsoft.Android.Sdk.TrimmableTypeMap/TrimmableTypeMapGenerator.cs | Passes framework assembly names into scanning and tightens JCW generation filtering logic. |
| src/Microsoft.Android.Sdk.TrimmableTypeMap/Scanner/JavaPeerScanner.cs | Tracks framework peers and controls array-entry emission based on cross-assembly references. |
| src/Microsoft.Android.Sdk.TrimmableTypeMap/Scanner/JavaPeerInfo.cs | Adds IsFrameworkAssembly and GenerateArrayEntries to peer model. |
| src/Microsoft.Android.Sdk.TrimmableTypeMap/Scanner/AssemblyIndex.cs | Indexes referenced types by referenced assembly to support framework peer reference detection. |
| src/Microsoft.Android.Sdk.TrimmableTypeMap/Generator/TypeMapAssemblyEmitter.cs | Updates documentation around __ArrayMapRank{N} anchors. |
| src/Microsoft.Android.Sdk.TrimmableTypeMap/Generator/RootTypeMapAssemblyGenerator.cs | Adds no-array-map initialization paths when max array rank is 0. |
| src/Microsoft.Android.Sdk.TrimmableTypeMap/Generator/ModelBuilder.cs | Adds additional unconditional types and prevents unconditional rooting for framework ACWs; gates array emission. |
| src/Microsoft.Android.Runtime.NativeAOT/Android.Runtime.NativeAOT/JavaInteropRuntime.cs | Uses the refactored JNIEnvInit initialization path and reuses common type/value manager creation helpers. |
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simonrozsival
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dev/simonrozsival/11052-nativeaot-typemap-initMay 22, 2026 08:20
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7b41d33 to
158bce0CompareUse NativeAOT scan DGML to identify retained managed types, intersect them with acw-map.txt, and emit concrete R8 keep rules for trimmable typemap NativeAOT builds. This avoids keeping the broad generated Java wrapper set when R8 is enabled. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Move DGML-based NativeAOT ProGuard generation into a separate MSBuild task so GenerateProguardConfiguration remains focused on linked assembly scanning. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Keep NativeAOT.targets free of ProGuard coordination properties. Let LlvmIr targets hardcode linked-assembly ProGuard timing for ILLink and NativeAOT, and keep the trimmable NativeAOT R8 mode flag with the trimmable NativeAOT typemap targets. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Move the trimmable NativeAOT common R8 rules to an embedded ProGuard resource, keep GenerateProguardConfiguration unchanged, add a shared trimmable typemap ProGuard target name with a CoreCLR stub, and restore the existing linked-assembly ProGuard target wiring. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Default NativeAOT trimmable typemap builds to AndroidLinkTool=r8 so the generated DGML-based keep rules are active without requiring users to opt in manually. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Tolerate the no-input typemap generation case by creating an empty assembly list, avoid nested framework reference scans, and disable XML resolver use when reading ILC DGML. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
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158bce0 to
3d4e1cdComparesimonrozsival
commented
May 23, 2026
MemberAuthor
@copilot there is a failure in CI, fix it: |
Agent-Logs-Url: https://github.com/dotnet/android/sessions/91b096b3-9ab7-4980-8234-097a0c3caca5 Co-authored-by: simonrozsival <374616+simonrozsival@users.noreply.github.com>
Contributor
Collect NativeAOT DGML files from per-RID intermediate output paths and merge their retained type metadata into the single ProGuard configuration consumed by R8/D8. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
simonrozsival
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May 25, 2026
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/review |
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⚠️ Needs Changes
Issue counts: 0 ❌ errors · 3
Summary
The approach is solid — intersecting ILC DGML metadata with acw-map.txt to generate focused ProGuard rules is well-designed, and the size reduction results are impressive (classes.dex from 259 kB → 15 kB).
Key items to address:
- O(n2) dedup in
LoadJavaTypesFromAcwMap—List.Contains()for dedup is quadratic; use aHashSetalongside the list. - Uncoded error messages —
Log.LogErrorcalls inGenerateNativeAotProguardConfigurationshould useLog.LogCodedErrorwithXA####codes andProperties.Resources. - Null-unsafe
GetManifestResourceStream— the new code path in R8.cs calls.CopyTo()on a potentially null stream.
Positive callouts:
- Clean separation: DGML-based logic stays in a dedicated task, leaving the existing
GenerateProguardConfigurationpath untouched. - Good use of
XmlReader(streaming) over LINQ-to-XML for parsing the large DGML files. - Proper
DtdProcessing.ProhibitandXmlResolver = nullfor XML security. - The MSBuild targets have correct
Inputs/Outputsfor incremental build support. - The
_ReadGeneratedTrimmableTypeMapAssembliesfallback withMakeDir+Touchis a nice resilience improvement.
Generated by Android PR Reviewer for issue #11449 · ● 18.8M
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Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
simonrozsival
commented
May 27, 2026
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/review |
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🤖 Code Review Summary
Verdict:
Overview
Well-structured PR that introduces DGML-based ProGuard rule generation for NativeAOT trimmable typemap builds. The architecture is clean: a dedicated GenerateNativeAotProguardConfiguration task handles the DGML↔ACW intersection, keeping it separate from the existing GenerateProguardConfiguration path. The results (classes.dex from 259 kB → 15 kB) are impressive.
Issues
| Severity | Count | Category |
|---|---|---|
| 1 | Missing error code documentation | |
| 💡 suggestion | 3 | Performance, documentation |
What's good
- JavaPeerScanner fix: Iterating over
ReferencedTypeNamesByAssemblyand checkingframeworkAssemblyNames.Contains()is more efficient than the reverse — good algorithmic improvement. - Proper XML security:
DtdProcessing.ProhibitandXmlResolver = nullon the DGML reader. - Clean task structure: Extends
AndroidTask, properTaskPrefix,[Required]properties with defaults, coded errors fromProperties.Resources, returns!Log.HasLoggedErrors. - Incremental build support: The
_GenerateTrimmableTypeMapProguardConfigurationtarget has properInputs/OutputsandFileWrites. - Good separation: CoreCLR gets an empty stub target with a TODO linking to
#11052, NativeAOT gets the real implementation. GetEmbeddedResourceStreamhelper: Nice extraction that adds null-checking the original code lacked.
Generated by Android PR Reviewer for issue #11449 · ● 30.7M
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Document the new XA43xx diagnostics, clarify the NativeAOT DGML/acw-map matching logic, and avoid unnecessary allocations in the ProGuard configuration task. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
simonrozsival
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May 27, 2026
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✅ LGTM — Clean, well-structured PR
Solid work generating NativeAOT ProGuard rules from DGML metadata. The results are impressive — 95% reduction in classes.dex size and 94% fewer Java classes.
Highlights:
- Good use of streaming
XmlReaderfor the large DGML files (24MB+) - Proper
DtdProcessing.Prohibit+XmlResolver = nullfor XML security - Clean separation: new
GenerateNativeAotProguardConfigurationtask handles DGML-based logic without touching the existingGenerateProguardConfigurationpath - Error codes (XA4319–4321) properly documented with markdown files and index entries
- Incremental build support via
Inputs/OutputsandFileWrites - The
GetEmbeddedResourceStreamhelper inR8.csis a nice refactor to avoid null-returningGetManifestResourceStream
Summary of suggestions (all 💡):
| # | Severity | Category | File |
|---|---|---|---|
| 1 | Performance | GenerateNativeAotProguardConfiguration.cs — use CopyIfStringChanged to avoid unnecessary timestamp updates | |
| 2 | 💡 | Patterns | GenerateNativeAotProguardConfiguration.cs — prefer !Log.HasLoggedErrors over return false |
| 3 | 💡 | Formatting | GenerateNativeAotProguardConfiguration.cs — file-scoped namespace |
| 4 | 💡 | Performance | GenerateNativeAotProguardConfiguration.cs — ordinal IndexOf |
| 5 | 💡 | MSBuild targets | NativeAOT.targets — BeforeTargets vs DependsOn |
Not flagged (no tests found): There are no unit tests for the new GenerateNativeAotProguardConfiguration task. Given the parsing logic for DGML XML and acw-map files, isolated tests would be valuable — but the PR description shows successful end-to-end validation, so this is not blocking.
CI: Unable to check CI status (tooling not authenticated in this environment).
Generated by Android PR Reviewer for issue #11449 · ● 21.8M
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simonrozsival
commented
May 27, 2026
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@copilot address all review comments |
Co-authored-by: simonrozsival <374616+simonrozsival@users.noreply.github.com>
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…Microsoft.Android.Sdk.TypeMap.Trimmable.NativeAOT.targets Co-authored-by: Jonathan Peppers <jonathan.peppers@microsoft.com>
Avoid rerunning IlcCompile from the outer multi-RID build when generating NativeAOT trimmable typemap ProGuard rules. The RID-specific inner builds already produce the DGML files consumed by the outer build. Also match DGML type metadata to assembly-qualified acw-map keys so same-named managed types from unrelated assemblies are not retained accidentally. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
…lc-metadata Resolve conflict in Trimmable.CoreCLR.targets: main now implements the CoreCLR proguard generation that the PR previously stubbed out as a TODO, so take main's _GenerateProguardAfterTargets PropertyGroup and drop the placeholder _GenerateTrimmableTypeMapProguardConfiguration target. The NativeAOT path retains its own _GenerateTrimmableTypeMapProguardConfiguration target in Trimmable.NativeAOT.targets. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
jonathanpeppers
approved these changes
May 28, 2026
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simonrozsival
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May 29, 2026 12:40
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Summary
IlcCompileby intersecting retained managed type metadata from ILC scan DGML withacw-map.txtGenerateNativeAotProguardConfigurationtask, leaving the existing linked-assemblyGenerateProguardConfigurationpath unchangedStacked on #11292
Related to dotnet/runtime#120204
Part of #10790
Part of #11052
Results
HelloWorld NativeAOT
android-arm64Release with trimmable typemap. Before is the existing default without R8 Java shrinking; after is the new default R8 behavior from this PR.classes.dexsizeclasses.dexin APKThe HelloWorld ILC scan DGML input is 24,044,488 bytes and
acw-map.txthas 27,234 lines. The generated ProGuard configuration has 49 rules.20-run measurement on Apple M1 for the isolated
GenerateNativeAotProguardConfigurationtask:Validation
MSBUILDDISABLENODEREUSE=1 ./dotnet-local.sh build src/Xamarin.Android.Build.Tasks/Xamarin.Android.Build.Tasks.csproj -c Debug -nr:false --nologo -v minimalMSBUILDDISABLENODEREUSE=1 ./dotnet-local.sh build src/Microsoft.Android.Sdk.TrimmableTypeMap/Microsoft.Android.Sdk.TrimmableTypeMap.csproj -c Debug -nr:false --nologo -v minimalMSBUILDDISABLENODEREUSE=1 ./dotnet-local.sh build samples/HelloWorld/HelloWorld/HelloWorld.DotNet.csproj -t:SignAndroidPackage -c Release -p:PublishAot=true -p:_AndroidTypeMapImplementation=trimmable -p:RuntimeIdentifier=android-arm64 -p:AndroidPackageFormat=apk -nr:false --nologo -v minimal