Iterating child tasks depends on knowing the size of AsyncTask, and changing the size of the task broke it. Instead of relying on mirroring the full structure in our out-of-process definitions, add a debug variable to libswift_Concurrency that contains the size of AsyncTask.
While we're there, add some more validation to child task enumeration. Check each child task's metadata pointer to make sure that it actually points to the AsyncTask metadata, and have the inner loop also increment and check ChildTaskLoopCount to stop runaway iteration in that loop.
Our Bazel builds have become more strict about libc++
dependencies recently, so these are required to pick up
declarations of `malloc` and `uint32_t`, respectively.
Most of the new inspection logic is in Remote Mirror. New code in swift-inspect calls the new Remote Mirror functions and formats the resulting information for display.
Specific Remote Mirror changes:
* Add a call to check if a given metadata is an actor.
* Add calls to get information about actors and tasks.
* Add a `readObj` call to MemoryReader that combines the read and the cast, greatly simplifying code chasing pointers in the remote process.
* Add a generalized facility to the C shims that can allocate a temporary object that remains valid until at least the next call, which is used to return various temporary arrays from the new calls. Remove the existing `lastString` and `lastChunks` member variables in favor of this new facility.
Swift-inspect changes:
* Add a new dump-concurrency command.
* Add a new `ConcurrencyDumper.swift` file with the implementation. The dumper needs to do some additional work with the results from Remote Mirror to build up the task tree and this keeps it all organized.
* Extend `Inspector` to query the target's threads and fetch each thread's current task.
Concurrency runtime changes:
* Add `_swift_concurrency_debug` variables pointing to the various future adapters. Remote Mirror uses these to provide a better view of a tasks's resume pointer.
rdar://85231338
We remove the existing `swift_reflection_iterateAsyncTaskAllocations` API that attempts to provide all necessary information about a tasks's allocations starting from the task. Instead, we split it into two pieces: `swift_reflection_asyncTaskSlabPointer` to get the first slab for a task, and `+swift_reflection_asyncTaskSlabAllocations` to get the allocations in a slab, and a pointer to the next slab.
We also add a dummy metadata pointer to the beginning of each slab. This allows tools to identify slab allocations on the heap without needing to locate every single async task object. They can then use `swift_reflection_asyncTaskSlabAllocations` on such allocations to find out about the contents.
rdar://82549631
We remove the existing `swift_reflection_iterateAsyncTaskAllocations` API that attempts to provide all necessary information about a tasks's allocations starting from the task. Instead, we split it into two pieces: `swift_reflection_asyncTaskSlabPointer` to get the first slab for a task, and `+swift_reflection_asyncTaskSlabAllocations` to get the allocations in a slab, and a pointer to the next slab.
We also add a dummy metadata pointer to the beginning of each slab. This allows tools to identify slab allocations on the heap without needing to locate every single async task object. They can then use `swift_reflection_asyncTaskSlabAllocations` on such allocations to find out about the contents.
rdar://82549631
This marks the decls as being defined in swift_Concurrency rather than
swiftCore. This corrects the dllstorage attribution which is required
to get the symbol exported properly.
Debugging tools can use _swift_concurrency_debug_asyncTaskMetadata to identify memory blocks as async task allocations by looking at their isa/metadata pointer.
rdar://72906895
