Summary:
Whenever we see a use of a lock, infer that the current method can run in a multithreaded context. But only report when there's a write under a lock that can be read or written without synchronization elsewhere.
For now, we only infer this based on the direct usage of a lock; we don't assume a caller runs in a multithreaded context just because its (transitive) callee can.
We can work on that trickier case later, and we can work on smarter inference that takes reads under sync into account. But for now, warning on unprotected writes of reads that occur under sync appears to be too noisy.
Reviewed By: jberdine
Differential Revision: D5918801
fbshipit-source-id: 2450cf2
Summary: Now that we report write-write races involving more than one write, we need to improve the traces accordingly.
Reviewed By: jberdine
Differential Revision: D6026845
fbshipit-source-id: b1366dd
Summary:
Previously, annotating something ThreadSafe meant "check that it is safe to run all of this procedure's methods in parallel with each other" (including self-parallelization).
This makes sense, but it means that if the user writes no annotations, we do no checking.
I'm moving toward a model of inferring when an access might happen on a thread that can run concurrently with other threads, then automatically checking that it is thread-safe w.r.t to all other accesses to the same memory (on or off the current thread thread).
This will let us report even when there are no `ThreadSafe` annotations.
Any method that is known to run on a new thread (e.g., `Runnable.run`) will be modeled as running on a thread that can run in parallel with other threads, and so will any method that is `synchronized` or acquires a lock.
In this setup, adding `ThreadSafe` to a method just means: "assume that the current method can run in parallel with any thread, including another thread that includes a different invocation of the same method (a self race) unless you see evidence to the contrary" (e.g., calling `assertMainThread` or annotating with `UiThread`).
The key step in this diff is changing the threads domain to abstract *what threads the current thread may run in parallel with* rather than *what the current thread* is. This makes things much simpler.
Reviewed By: jberdine
Differential Revision: D5895242
fbshipit-source-id: 2e23d1e
Summary: Using Conjunction for thread join has known false negatives. Finer grained recording of threading information fixes this.
Reviewed By: sblackshear
Differential Revision: D5111161
fbshipit-source-id: aab483c
Summary: If two public methods touch the same state and only one is marked `ThreadSafe`, it's reasonable to report unsafe accesses on both of them.
Reviewed By: peterogithub
Differential Revision: D4785038
fbshipit-source-id: 5a80da4
Summary:
No new functionality here; mostly `FN_` tests documenting our current limitations.
Will start chipping away at the false negatives in follow-up diffs.
Reviewed By: peterogithub
Differential Revision: D4780013
fbshipit-source-id: 7a0c821
Sam Blackshear
Peter O'Hearn