Summary: Report at most one read/write race or unprotected write per access path per method
Reviewed By: sblackshear, jvillard
Differential Revision: D4590815
fbshipit-source-id: 3c3a9d9
Summary:
To address a common source of false positives observed in D4494901.
We don't do anything with `release` yet, but can model it as releasing ownership in the future if we want to enforce correct usage of `SynchronizedPool`'s.
Reviewed By: peterogithub
Differential Revision: D4593635
fbshipit-source-id: 621e937
Summary: Reports on reads that have one or more conflicting writes. When you report, say which other methods race with it.
Reviewed By: sblackshear
Differential Revision: D4538793
fbshipit-source-id: 47ce700
Summary: Thread-local variables can't be shared between threads, so it's safe to mutate them outside of synchronization
Reviewed By: jeremydubreil
Differential Revision: D4568316
fbshipit-source-id: 0634cad
Summary:
We waste a lot of space storing the types of field accesses and comparing them sets/maps with access paths.
Yet almost none of the code ever looks at these types (only a tiny piece of code in thread-safety).
If we know the base type, we have enough information to recover the type of the field.
Let's do that instead.
Reviewed By: jeremydubreil
Differential Revision: D4567996
fbshipit-source-id: e7fd2da
Summary: Should stop us from reporting on benign races of fields that are caching resources.
Reviewed By: peterogithub
Differential Revision: D4538037
fbshipit-source-id: 15236b4
Summary: This will be important for maintaining ownership of `View`'s, which involve a lot of casting.
Reviewed By: peterogithub
Differential Revision: D4520441
fbshipit-source-id: fdef226
Summary:
Previously, we would lose track of ownership in code like
```
Obj owned = new Obj();
Obj stillOwned = id(owned); // would lose ownership here
stillOwned.f = ... // would report false alarm here
```
This diff partially addresses the problem by adding a notion of "unconditional" (always owned) or "conditional" (owned if some formal at index i is owned) ownership.
Now we can handle simple examples like the one above.
I say "partially" because we still can't handle cases where there are different reasons for conditional ownership, such as
```
oneOrTwo(Obj o1, Obj o2) { if (*) return o1; else return o2; } // we won't understand that this maintains ownership if both formals are owned
Obj stillOwned = oneOrTwo(owned1, owned2);
stillOwned.f = ... // we'll report a false alarm here
```
This can be addressed in the future, but will require slightly more work
Reviewed By: peterogithub
Differential Revision: D4520069
fbshipit-source-id: 99c7418
Summary: This will make it a cinch to track new "attributes" of memory locations, and to propagate more complex attributes such as conditional ownership (coming in a future diff).
Reviewed By: peterogithub
Differential Revision: D4523143
fbshipit-source-id: 57aa133
Summary:
At one point I thought we'd want to have lots of different schedulers for things like exploring loops in different orders, but that hasn't materialized.
Let's make the common use-case simpler by hiding the `Scheduler` parameter inside the `AbstractInterpreter` module.
We can always expose `MakeWithScheduler` later if we want to.
Reviewed By: jberdine
Differential Revision: D4508095
fbshipit-source-id: 726e051
Summary:
This fixes false positives we had in fields written by callees of a constructor (see new E2E test).
This is also a bit cleaner than what we did before; instead of special-casing constructors, we just use the existing ownership concept.
Reviewed By: peterogithub
Differential Revision: D4505161
fbshipit-source-id: a739ebc
Summary:
Constants are always "owned" in the sense that no one can mutate them.
In code like
```
Obj getX(boolean b) {
if (b) {
return null;
}
return new Obj();
}
```
, we need to understand this in order to infer that the returned value is owned.
This should fix a few FP's that I've seen.
Reviewed By: peterogithub
Differential Revision: D4485452
fbshipit-source-id: beae15b
Summary:
This diff adds a set of access paths holding a value returned from a method annotated with Functional to the domain.
If a "functional" value is written to a field, we won't count that right as an unprotected access.
The idea is to be able to use the Functional annotation to get rid of benign race false positive, such as:
```
Functional T iAlwaysReturnTheSameThing();
T mCache;
T memoizedGetter() {
if (mCache == null) {
mCache = iAlwaysReturnTheSameThing();
}
return mCache;
}
```
Although there is a write-write race on `mCache`, we don't care because it will be assigned to the same value regardless of which writer wins.
Reviewed By: peterogithub
Differential Revision: D4476492
fbshipit-source-id: cfa5dfc
Summary:
We warn on unsafe accesses to fields that occur in a public method (or are reachable from a public method).
We ought not to consider VisibleForTesting methods as public, since they are only public for testing purposes.
Reviewed By: peterogithub
Differential Revision: D4477648
fbshipit-source-id: 5f58914
Summary:
The thread-safety and annotation reachibility analyses were defining ugly custom versions of override_exists with refs.
Let's give them a canonical, ref-free version instead.
Reviewed By: jberdine
Differential Revision: D4475777
fbshipit-source-id: 0bb45fc
Summary: Simple model for List methods that write to the collection.
Reviewed By: peterogithub
Differential Revision: D4453381
fbshipit-source-id: 19edc51
Summary:
One of the things that confuses me about the current annotations API is that there's a lot of ways to do the same thing.
Some of the concepts like `annotated_signature` are only really needed by Eradicate.
This diff removes usages of `annotated_signature` outside of Eradicate (everyone else was just using `get_annotated_signature` as a roundabout way to get the return annotation of a procedure).
In the future, I'll move `get_annotated_signature` and other Eradicate-specific functionality into its own module inside the Eradicate directory.
Reviewed By: jberdine
Differential Revision: D4472058
fbshipit-source-id: 5bb0846
Summary:
Previously, we would correctly be silent on code like `x = new T(); x.f = ...`, but would wrongly warn on code like `x = makeT(); x.f = ...`.
The reason is that we only allowed ownership through direct allocation.
This diff adds a boolean that specifies whether the return value is owned as part of the summary.
This allows us to correctly handle many common cases of (transitively) returning a freshly allocated object, but still won't work for understanding that ownership is maintained in examples like
`x = new T(); y = id(x); y.f = ...`.
Reviewed By: jvillard
Differential Revision: D4456864
fbshipit-source-id: b5eec02
Summary:
Remove the remaining uses of polymorphic equality `=`.
In case of basic types, this is replaced by String.equal or Int.equal.
In case of `= []`, this is replaced by `List.is_empty`.
In case of `= None`, this is replaced by `is_none`.
In case of a datatype definition such as `type a = A | B`,
a `compare_a` function is defined by adding `type a = A | B [@deriving compare]`
and a `equal_a` function is defined as `let equal_a = [%compare.equal : a]`.
In case of comparison with a polymorphic variant `= `Yes`, the equality
defined in `PVariant.(=)` is used. Typically, `open! Pvariant` is added
at the beginning of the file to cover all the uses.
Reviewed By: jberdine
Differential Revision: D4456129
fbshipit-source-id: f31c433
Summary:
In code like
```
foo(o) {
iWriteToF(o)
}
```
, the condtional write to `f` in `iWriteToF` should become a conditional write for `foo`.
Reviewed By: peterogithub
Differential Revision: D4429160
fbshipit-source-id: f111ac4
Summary:
In code like
```
foo() {
Object local = new Object();
iWriteToAField(local);
}
```
, we don't want to warn because the object pointed to by `local` is owned by the caller, then ownership is transferred to the callee.
This diff supports this by introducing a notion of "conditional" and "unconditional" writes.
Conditional writes are writes that are rooted in a formal of the current procedure, and they are safe only if the actual bound to that formal is owned at the call site (as in the `foo` example above).
Unconditional writes are rooted in a local, and they are only safe if a lock is held in the caller.
Reviewed By: peterogithub
Differential Revision: D4429131
fbshipit-source-id: 2c6112b
Summary:
Races on volatile fields are less concerning than races on non-volatile fields because at least the read/write won't result in garbage.
For now, let's de-prioritize these writes by ignoring them.
Reviewed By: peterogithub
Differential Revision: D4434023
fbshipit-source-id: 05043ba
Summary:
If an access path rooted in some parameter `p` is accessed outside of synchronizaton, but `p` is owned by the caller, then we should not warn.
We will implement this by separating writes into "conditional" (safe if a certain parameter is owned by the caller" and "unconditional" (safe only if the caller synchronizes appropriately).
This diff just introduces the map type for conditional writes and changes the transfer functions accordingly.
We'll actually use the map in a follow-up.
Reviewed By: peterogithub
Differential Revision: D4400987
fbshipit-source-id: d2b8af8
Summary:
Similar to marking classes ThreadConfined, we want to support marking fields as well.
The intended semantics are: don't warn on writes to the marked field outside of syncrhonization, but continue to warn on accesses to subfields.
Reviewed By: peterogithub
Differential Revision: D4406890
fbshipit-source-id: af8a114
Summary:
Adding models that allow us to warn on unguarded accesses to subclasses of `Map`, but not on accesses of threadsafe containers like `ConcurrentMap`.
Lots more containers to model later, but stopping at `Map`s for now to make sure the approach looks ok.
Reviewed By: jvillard
Differential Revision: D4385306
fbshipit-source-id: d791eee
Summary: These methods should only be called from other methods that also run on the UI thread, and they should not be starting new threads.
Reviewed By: peterogithub
Differential Revision: D4383133
fbshipit-source-id: 6cb2e40
Summary:
A domain should not definite its initial state, since distinct users of the domain may want to choose different initial values.
For example, one user might want to bind all of the formals to some special values, and one user might want the initial domain to be an empty map
This diff makes this distinction clear in the types by (a) requiring the initial state to be passed to the abstract interpreter and (b) lifting the requirement that abstract domains define `initial`.
Reviewed By: jberdine
Differential Revision: D4359629
fbshipit-source-id: cbcee28
Cristiano Calcagno
Peter O'Hearn
Sam Blackshear