[runtime] Extend JNI remapping for R8 - #12817
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Copilot review overview
🟡 Changes recommended
Critical native layout compatibility and moderate JNI owner-retention issues remain unresolved.
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Review effort: Lite
Findings: 1
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What changed in this PR
Extends the reusable JNI remapping runtime contract for R8, including reverse type, field, descriptor, and inherited-member remapping.
Changes:
- Expands native remapping tables and XML generation.
- Integrates remapping into trimmable type maps and Java.Interop lookups.
- Adds runtime, generator, and Java fixture tests.
| File | Reviewed change |
|---|---|
src/Xamarin.Android.Build.Tasks/Utilities/JniRemappingAssemblyGenerator.cs |
Generates expanded remapping tables. Nit: use NullableExtensions.IsNullOrEmpty() at both reported locations. |
src/Xamarin.Android.Build.Tasks/Tests/Xamarin.Android.Build.Tests/Tasks/GenerateJniRemappingNativeCodeTests.cs |
Tests generated LLVM remapping data. |
src/Xamarin.Android.Build.Tasks/Tasks/GenerateJniRemappingNativeCode.cs |
Parses reverse, method, and field remapping entries. |
src/native/common/include/managed-interface.hh |
Extends the native remapping layout. Critical bug: checked-in MonoVM/CoreCLR stubs still use the old layout. |
src/Mono.Android/Microsoft.Android.Runtime/TrimmableTypeMapValueManager.cs |
Applies forward type remapping during casts. |
src/Mono.Android/Microsoft.Android.Runtime/TrimmableTypeMapTypeManager.cs |
Adds reverse type and field lookup support. |
src/Mono.Android/Microsoft.Android.Runtime/TrimmableTypeMap.cs |
Supports remapped activation and registration. Moderate performance issue: reverse results are repeatedly allocated instead of cached. |
src/Mono.Android/Microsoft.Android.Runtime/JniRemappingLookup.cs |
Implements native remapping table lookups. |
external/Java.Interop/tests/Java.Interop-Tests/java/net/dot/jni/test/FieldRemapRenamedBase.java |
Adds renamed-field test fixture. |
external/Java.Interop/tests/Java.Interop-Tests/java/net/dot/jni/test/FieldRemapDerived.java |
Adds derived-field test fixture. |
external/Java.Interop/tests/Java.Interop-Tests/java/net/dot/jni/test/FieldRemapBase.java |
Adds base-field test fixture. |
external/Java.Interop/tests/Java.Interop-Tests/Java.Interop/JniPeerMembersTests.cs |
Tests field, inheritance, and descriptor remapping. |
external/Java.Interop/tests/Java.Interop-Tests/Java.Interop/JavaVMFixture.cs |
Configures remapping test data. |
external/Java.Interop/tests/Java.Interop-Tests/Java.Interop-Tests.csproj |
Includes Java test fixtures. |
external/Java.Interop/src/Java.Interop/PublicAPI.Unshipped.txt |
Records new public APIs. |
external/Java.Interop/src/Java.Interop/Java.Interop/JniType.cs |
Adds non-throwing field lookup helpers. |
external/Java.Interop/src/Java.Interop/Java.Interop/JniRuntime.ReflectionJniTypeManager.cs |
Adds default field-remapping behavior. |
external/Java.Interop/src/Java.Interop/Java.Interop/JniRuntime.JniTypeManager.cs |
Defines field-remapping APIs. |
external/Java.Interop/src/Java.Interop/Java.Interop/JniPeerMembers.JniStaticMethods.cs |
Adds inherited static-method fallback. Moderate bug: preserve the target declaring type. |
external/Java.Interop/src/Java.Interop/Java.Interop/JniPeerMembers.JniStaticFields.cs |
Adds static-field remapping. Moderate bug: retain the target owner for static access. |
external/Java.Interop/src/Java.Interop/Java.Interop/JniPeerMembers.JniInstanceMethods.cs |
Applies method and constructor remapping. |
external/Java.Interop/src/Java.Interop/Java.Interop/JniPeerMembers.JniInstanceFields.cs |
Applies instance-field remapping. |
external/Java.Interop/src/Java.Interop/Java.Interop/JniPeerMembers.cs |
Adds shared remapping and base-member helpers. |
> AI-generated fix. Produced by the `nightly-fix-finder` agentic workflow. ### Problem `JavaSourceUtils` emitted a hardcoded, uncoded error when an `@(Reference)` item was neither a Java source directory nor a `.jar` or `.aar` file. This customer-facing diagnostic bypassed the build task resource system and could not be localized. ### Fix Added localized error `XA1037` to the English resources and checked-in accessor, and updated `JavaSourceUtils` to emit the coded resource while preserving the message, argument, severity, and control flow. Added the corresponding XA1037 message documentation, index entry, and table-of-contents entry. ### Validation - `AndroidSdkDirectory="$GITHUB_WORKSPACE/bin/Debug/android-sdk" AndroidNdkDirectory="$GITHUB_WORKSPACE/bin/Debug/android-ndk" ./build.sh Prepare` — passed - `GRADLE_USER_HOME=/tmp/gh-aw/agent/gradle AndroidSdkDirectory="$GITHUB_WORKSPACE/bin/Debug/android-sdk" AndroidNdkDirectory="$GITHUB_WORKSPACE/bin/Debug/android-ndk" ./dotnet-local.sh build src/AndroidBuildConfig/AndroidBuildConfig.csproj --no-restore -m:1` — passed - `GRADLE_USER_HOME=/tmp/gh-aw/agent/gradle AndroidSdkDirectory="$GITHUB_WORKSPACE/bin/Debug/android-sdk" AndroidNdkDirectory="$GITHUB_WORKSPACE/bin/Debug/android-ndk" ./dotnet-local.sh build external/Java.Interop/src/Java.Interop.Tools.Maven/Java.Interop.Tools.Maven.csproj --no-restore -m:1` — passed - `GRADLE_USER_HOME=/tmp/gh-aw/agent/gradle AndroidSdkDirectory="$GITHUB_WORKSPACE/bin/Debug/android-sdk" AndroidNdkDirectory="$GITHUB_WORKSPACE/bin/Debug/android-ndk" ./dotnet-local.sh build src/Xamarin.Android.Tools.Aidl/Xamarin.Android.Tools.Aidl.csproj --no-restore -m:1` — passed - `GRADLE_USER_HOME=/tmp/gh-aw/agent/gradle AndroidSdkDirectory="$GITHUB_WORKSPACE/bin/Debug/android-sdk" AndroidNdkDirectory="$GITHUB_WORKSPACE/bin/Debug/android-ndk" ./dotnet-local.sh build src/Xamarin.Android.Build.Tasks/Xamarin.Android.Build.Tasks.csproj --no-restore -p:BuildProjectReferences=false -m:1` — passed ### Fix-finder metadata - Script: `08-string-literal-error-messages` - Score: `26/30` (actionability: `9`, safety: `9`, scope: `8`) > Generated by [Nightly Fix Finder](https://github.com/dotnet/android/actions/runs/35045607028) · copilot · gpt56 · 105.2 AIC · ⌖ 27.2 AIC · ⊞ 23.3K · [◷](https://github.com/search?q=repo%3Adotnet%2Fandroid+%22gh-aw-workflow-id%3A+nightly-fix-finder%22&type=pullrequests) <!-- gh-aw-agentic-workflow: Nightly Fix Finder, engine: copilot, model: gpt-5.6-sol, id: 35045607028, workflow_id: nightly-fix-finder, run: https://github.com/dotnet/android/actions/runs/35045607028 --> <!-- gh-aw-workflow-id: nightly-fix-finder --> <!-- gh-aw-workflow-call-id: dotnet/android/nightly-fix-finder -->
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Context: #12354 Context: #12409 Context: #7479 Mono's TypeManager already caches peer activation constructors, but Microsoft.Android.Runtime.JavaMarshalValueManager.TryConstructPeer() still repeats reflection lookup for CoreCLR. Add the same cache pattern privately to JavaMarshalValueManager without adding a dependency on the legacy TypeManager implementation. Preserve XA-first lookup, JI fallback, missing-constructor results, constructor matching, existing peer identity, exception behavior, JNI reference ownership, and constructor-preservation annotations. Add focused coverage for cached/concurrent resolution and actual CoreCLR activation, including constructor failures and reference ownership. The trimmed Release CoreCLR device run passes all 13 new cases and 3 existing ReflectionCreateProxy cases. A Pixel 7 benchmark of warm TryConstructPeer activation and disposal improves from 3161.501 ns to 2915.512 ns (7.78% less time), with managed allocations reduced from 248 B to 144 B per operation. Separate matched Jetchat and MAUI sample-content startup checks detect no statistically clear regression; they do not establish a startup speedup. Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>
Bumps com.android.tools:r8 from 9.4.17 to 9.4.24. --- updated-dependencies: - dependency-name: com.android.tools:r8 dependency-version: 9.4.24 dependency-type: direct:production update-type: version-update:semver-patch ... Signed-off-by: dependabot[bot] <support@github.com> Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
## Motivation The existing Intune/MAM JNI method-remapping path stores target type and method names as stable NUL-terminated UTF-8 strings in generated native data. The old path materialized those names as managed UTF-16 strings and then encoded them back to UTF-8 for `FindClass` and `GetMethodID`. That round trip is unnecessary and becomes more important as remapping is reused by larger consumers such as R8. ## Approach - Add pointer-backed target type, method-name, and method-signature values to `ReplacementMethodInfo`. - Keep pointer and string representations independent so reading a compatibility string property does not implicitly decode native memory. - Add `JniType` lookup paths for pointer/pointer and mixed pointer/span member names and signatures. - Let `JniPeerMembers` retain a replacement type pointer and use it directly for `FindClass` and later member-remapping lookups. - Keep native pointers in `JniMethodInfo` Debug metadata and decode them only if `Name`, `Signature`, or `ToString()` is explicitly requested. - Retain the existing string/span paths for custom `JniTypeManager` implementations. - Document UTF-8 encoding, NUL termination, ownership, and lifetime requirements for every pointer API. The successful generated-remapping path therefore passes the pregenerated UTF-8 type, method name, and optional signature directly to JNI without copying them or converting them to a managed string. This PR is method-only and does not add R8, field remapping, reverse-type mapping, inherited-member fallback, or NativeAOT remapping support. ## Relationship to other PRs - This PR is based directly on `main` and provides the Java.Interop representation and JNI lookup primitives. - #12796 supplies the generated pointers, performs managed table search, and removes the native remapping P/Invokes. - #12692 can build on this stack to add the R8-specific field, reverse-type, inherited-member, and NativeAOT pieces. ## Validation - Java.Interop Debug build. - Java.Interop `JniPeerMembersTests`: 12 passed, 1 skipped. - The JVM fixture exercises stable unmanaged UTF-8 type/name/signature storage, signature fallback, instance/static lookup, and instance-to-static remapping.
Emit the existing Intune remapping tables as a self-describing data block, pass it through JNIEnv initialization, and share UTF-8 binary lookup across MonoVM and CoreCLR without per-call P/Invokes. Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>
Use System.Text.Ascii for the common UTF-8/UTF-16 comparison path and a streaming Rune fallback for non-ASCII names. Keep replacement types and exact method signatures in generated native memory, avoid source metadata strings, and cache generator UTF-8 sort keys. Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>
Exercise allocation-free UTF-8/UTF-16 comparison for a non-ASCII replacement type and method name through the CoreCLR device remapping path. Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>
Compare UTF-8 and UTF-16 ASCII names in vector-sized chunks so binary-search ordering rescans at most one chunk after Ascii.Equals reports a mismatch. Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>
The native assembler populates the JniRemappingData table pointers during code generation, so suppress CS0649 for those two fields just like the existing generated methods pointer. Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>
Update the Xamarin.Forms CoreCLR R8 Release APK description from the matching failed CI test attachment. macOS and Windows produced the same package size; their assembly stores differed by only 16 bytes. Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>
Use the generator UTF-8 sort-key cache when computing serialized string lengths so each distinct remapping string is encoded only once. Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>
Use Encoding.UTF8.GetByteCount for serialized lengths so signatures and other non-sort values are not retained in the sort-key cache. Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>
Override the combined replacement-type lookup in both Android type managers so generated UTF-8 table misses do not fall through into a second compatibility string search. Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>
Add target descriptors, field remapping, and renamed-owner fallback while preserving existing custom type-manager defaults. Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>
Emit reverse type, field, and target descriptor tables and consume them in Microsoft.Android.Runtime and the trimmable type map. Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>
Keep legacy native stubs layout-compatible, retain redirected static member owners, and use the nullable string helpers. Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>
Qualify System.Math in the shared test fixture and cache reverse JNI type lookup results used by activation paths. Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>
Android cannot install JavaVMFixture's custom type manager, so keep the synthetic remapping tests on the desktop Java.Interop test path. Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>
Remove duplicated method-index entries carried through the lower-layer generator optimization so each native table is emitted once. Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>
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Summary
Extend the reusable JNI remapping contract shared by runtime consumers:
JniTypeManagerand Intune/MAM defaultsDepends on #12796.
Related to #12814 and #12535.
Scope
This is only the reusable contract/runtime layer. It intentionally defers:
Tests
Java.Interop-Tests:JniPeerMembersTests— 26 passed, 1 skippedXamarin.Android.Build.Tests:GenerateJniRemappingNativeCodeTests— 6 passedJniRemappingDatalayout compile-time assertions