[Mono.Android] JNI handles are now in a "control block" #10179
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Originally from: #10125 Context: dotnet/java-interop#1339 These are changes to Mono's GC bridge implementation, such that the same code can be used on both Mono and CoreCLR. The base `JavaObject` type has changes such as: ```diff --[NonSerialized] IntPtr handle; --[NonSerialized] JniObjectReferenceType handle_type; --[NonSerialized] IntPtr weak_handle; --[NonSerialized] int refs_added; ++unsafe JniObjectReferenceControlBlock* jniObjectReferenceControlBlock; ``` And the new `JniObjectReferenceControlBlock` struct is defined as: internal struct JniObjectReferenceControlBlock { public IntPtr handle; public int handle_type; public IntPtr weak_handle; public int refs_added; } * Each `JavaObject` allocation now has a `NativeMemory.AllocZeroed()` call for this struct. * However, we only have to read a single field now using Mono's native embedding API: ```diff --info->handle = mono_class_get_field_from_name (info->klass, const_cast<char*> ("handle")); --info->handle_type = mono_class_get_field_from_name (info->klass, const_cast<char*> ("handle_type")); --info->refs_added = mono_class_get_field_from_name (info->klass, const_cast<char*> ("refs_added")); --info->weak_handle = mono_class_get_field_from_name (info->klass, const_cast<char*> ("weak_handle")); ++info->jniObjectReferenceControlBlock = mono_class_get_field_from_name (info->klass, const_cast<char*> ("jniObjectReferenceControlBlock")); ``` We are hoping this results in ~the same performance as before, with the flexibility to support multiple GC bridge implementations and runtimes. Co-authored-by: Marek Habersack <[email protected]>
grendello
approved these changes
Jun 9, 2025
|
This is close now, but crashes partway through test suite: Some of the configurations didn't crash. |
We were using it incorrectly - there's no need to fetch/set values of managed object fields. The correct thing to do is to read/write them on the control block itself.
Conflicts: external/Java.Interop
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Originally from: #10125
Context: dotnet/java-interop#1339
These are changes to Mono's GC bridge implementation, such that the same code can be used on both Mono and CoreCLR.
The base
JavaObjecttype has changes such as:And the new
JniObjectReferenceControlBlockstruct is defined as:Each
JavaObjectallocation now has aNativeMemory.AllocZeroed()call for this struct.However, we only have to read a single field now using Mono's native embedding API:
We are hoping this results in ~the same performance as before, with the flexibility to support multiple GC bridge implementations and runtimes.