Summary: The map from `CreatedLocation` to `MethodCalls` already takes care of the association from create methods to their set props. `MethodCall` comparison should be oblivious the the receiver, otherwise, we risk mistakenly considering two props set at different locations as different.
Reviewed By: skcho
Differential Revision: D18829388
fbshipit-source-id: b5a0d628d
Summary: This diff check and report on every nodes. Problem of the previous design is that it has to report alarms only with the abstract memory of the exit node. However, the new abstract value becomes imprecise at every join points on the path to the exit node, since it is using inverted map, i.e., under-approximation on collecting called methods. As a solution, this diff report on every nodes where `.build` is called with the abstract memory at that node.
Reviewed By: ezgicicek
Differential Revision: D18809449
fbshipit-source-id: 4fd6165d1
Summary: Current method call comparison is too strong. As exemplified with the new test, one can also set the required prop by calling a version which contains the suffixes. The domain should take care of such cases now.
Reviewed By: skcho
Differential Revision: D18808869
fbshipit-source-id: 9f7672e75
Summary:
Sometimes clang9 does not return a boxing method (a name of function to apply), e.g., [@("str")].
To solve the issue, this diff uses "unknownSelector:" instead of giving up the translation.
Reviewed By: dulmarod
Differential Revision: D18831844
fbshipit-source-id: b9324ba39
Summary: This enables us to quickly pick up the Component typ when checking which required props to check.
Reviewed By: skcho
Differential Revision: D18807925
fbshipit-source-id: 47e407394
Summary: This diff checks litho condition on the new abstract value. This is triggered with `--new-litho-domain`, but it is intra-procedural as of now.
Reviewed By: ezgicicek
Differential Revision: D18783203
fbshipit-source-id: 98570104e
Summary: This diff adds a map from an object to a set of methods that has been called.
Reviewed By: ezgicicek
Differential Revision: D18781461
fbshipit-source-id: 47c10adaa
Summary: This adds a map from access expressions to locations where specific object is created by `create` method call.
Reviewed By: ezgicicek
Differential Revision: D18779985
fbshipit-source-id: f327450cd
Summary: This diff stack is to revise overall domain and semantics of litho checker. Some of the following diffs will not have visible changes until we replace the current checker with the new one.
Reviewed By: ezgicicek
Differential Revision: D18779592
fbshipit-source-id: d210d9bd1
Summary:
This can happen for a number of reasons that are not errors (mostly the exit node being unreachable) so isn't actionable, and definitely not worth showing the user. It could be a debug message but I don't think that's even worth it. Other checkers don't warn in similar circumstances.
With OCaml 4.08 we started actually seeing these error messages (differences in flushing behaviour?) so their annoying nature was revealed.
Reviewed By: ngorogiannis
Differential Revision: D18808460
fbshipit-source-id: a47a1dcb4
Summary:
Also add logic for recognising excessive timeouts. Refactor the code
around timeouts a little.
Reviewed By: artempyanykh
Differential Revision: D18807836
fbshipit-source-id: df5a1b566
Summary:
`Object.wait()` must be called on a locked monitor and it releases the
lock immediately, as far as other threads are concerned
(it also magically re-takes the lock when the monitor is `notified`).
Starvation can only occur if the UI thread is waiting
a lock that is distinct to that being waited on.
The check present was over-approximate in that it was checking that there exists a lock held by the UI thread and the thread issuing the `wait`, but did not make sure that lock was *not* the one waited on.
Amusingly, the e2e test was correct, but the reporting code wasn't.
Reviewed By: dulmarod
Differential Revision: D18782919
fbshipit-source-id: b3b98239e
Summary: The clang plugin exports C++ mangled names in hashed form for perf reasons, so we need to hash the incoming mangled names in the profiler samples, so that we can compare them.
Reviewed By: skcho
Differential Revision: D18761842
fbshipit-source-id: 3072b5e33
Summary: Similar to constructor established attributes, we do the same here for static initializers. That is, attributes of static properties are injected into the initial state of every method.
Reviewed By: ezgicicek
Differential Revision: D18763192
fbshipit-source-id: 3879a27c5
Summary:
For now lets support the simplest form: "//"-style comments.
Having comments is useful:
1. It serves as documentation for API.
2. It serves as justification of why such and such method or param is
nullable or not (so the future readers can understand the reasoning of
the person who added the signature).
Reviewed By: artempyanykh
Differential Revision: D18762289
fbshipit-source-id: 90c515ea8
Summary: Raises an error when weakSelf is used multiple times in a block. The issue is that there could be unexpected behaviour. Even if `weakSelf` is not nil in the first use, it could be nil in the following uses since the object that `weakSelf` points to could be freed anytime.
Reviewed By: skcho
Differential Revision: D18765493
fbshipit-source-id: 37fc652e3
Summary:
This diff enables parsing and auto-formatting documentation
comments (aka docstrings).
I have looked at this entire diff and manually made some changes to
improve the formatting. In some cases it looked like it would take too
much time, or benefit from someone more familiar with the code doing
it, and I instead disabled auto-formatting docstrings in those files.
Also, there are some source files where the docstrings are invalid,
and some where the structure detected by the parser appears not to
match what was intended. Auto-formatting has been disabled for these
files.
Reviewed By: ezgicicek
Differential Revision: D18755888
fbshipit-source-id: 68d72465d
Summary:
RacerD is angelic in the sense that when a method has no summary, no accesses are added to the symbolic state when we call that method. However, when the method returns an object we then proceed to access, this leads to non-angelic behaviour: if the object is assumed to be un-owned, then the accesses may lead to a race.
This manifests itself on Litho components, which are generated code without sources and thus RacerD has no CFG to analyse, and therefore produces no summary. The `Builder` patterns used in these classes are ubiquitous, and full of spurious races due to the fact that the returned objects, even though freshly allocated, are un-owned as far as RacerD knows.
Here, instead of going full-angelic and assuming that every method without a summary returns an owned object (which is a bit extreme), we try to model the `Builder` pattern wrt ownership. That is, static `create` methods returning `Builder` types are assumed to return full ownership; and, non-static methods of a `Builder` class which return the same type as their receiver are assumed to return conditional ownership.
Reviewed By: ezgicicek
Differential Revision: D18748423
fbshipit-source-id: bd53d4b67
Summary: This diff extends the bound domain to express multiplication of bounds in some simple cases.
Reviewed By: ezgicicek
Differential Revision: D18745246
fbshipit-source-id: 4f2dcb42c
Summary:
One standard way to schedule work is by starting a thread. We treat this by
- Treating invocations of `start` on a receiver with the `Runnable _` attribute as scheduling that runnable for parallel execution in the background (as opposed to on the UI thread).
- If `start` is used on an object of a subclass of `Thread` everything already works thanks to the `get_exp_attributes` function which will implicitly ascribe to an expression the attribute `Runnable _` if the expression points to an object with a known `run` method. This will even take care of some degree of dynamic dispatch, yay!
- If `start` is used on a `Thread` object which has been created with a constructor call provided with a `Runnable` argument, we have to appropriately model that constructor call, which is what is done in `do_call`.
Reviewed By: jvillard
Differential Revision: D18726676
fbshipit-source-id: 0bd83c28e
Summary:
A current blind spot is when object construction stores specific executors / runnables to object fields, which are then never mutated and accessed from normal methods. IOW the attributes established in the constructor are necessary to report properly inside a normal method (assuming these attributes are not invalidated by method code).
To achieve this, first we retain a subset of the final state attributes in the summary (only those that affect instance variables, in constructor methods). Then, when we analyse a non-constructor method:
- we analyse all constructors
- remove all attributes from the attribute map whose key is not an expression of the form `this.x. ...`
- re-localise all remaining keys so that they appear as rooted in the `this` local variable of the current procedure
- join (intersect) all such attribute maps
- use the result in place of initial state as far as the attribute map is concerned for the analysis of the current procedure, which can now start.
This means we can catch idioms that use side-effectful initialisation for configuring certain object fields like executors or runnables.
Reviewed By: jvillard
Differential Revision: D18707890
fbshipit-source-id: 42ac6108f
Summary: Another way to schedule work in android is by posting it to a `Handler`. A handler can be constructed out of the main looper, which forces it to schedule work on the UI thread. To model all this, we add syntactic models for getting the main looper and for creating handlers, and dataflow attributes for tracking that an expression is a looper/the main looper, or a handler constructed out of a looper.
Reviewed By: skcho
Differential Revision: D18706768
fbshipit-source-id: 7c46e6913
Summary:
We already have a number of `[pkg].Preconditions.checkNotNull`
modelled, but the one from `androidx` is missing yet widely used.
Reviewed By: mityal
Differential Revision: D18748550
fbshipit-source-id: 83d3317ae
Summary:
The introduction of inferbo intervals as pulse attributes creates the
first relational attributes. To make sense of inferbo intervals
appearing in summaries when in a caller context, we need to substitute
the abstract values they contain in the callee with the abstract values
they correspond to in the caller.
This has a significant consequence: we have to delay the check that
arithmetic constraints in the callee are satisfiable at the call-site
until *after* we have discovered all the relationships between callee
values and caller values from the heap. To solve this, we now run an
arithmetic constraints check *after* having materialised all the
addresses.
We also need to translate the abstract values in the attributes in the
post before recording them in the caller, for the same reasons.
Quite some code in this diff is concerned with substituting pulse values
inside inferbo intervals. There is a complication there too: even after
having discovered relationships between caller and callee abstract
values induced by the heap shapes, there could be abstract values in the
callee's attributes that we haven't seen yet. We need to make up new
values for these in the caller, so this substitution has to return a
potentially extended substitution.
Reviewed By: skcho
Differential Revision: D18745695
fbshipit-source-id: 077ae7670
Summary:
New syntax f1 AND-WITH-WITNESSES f2 : predicate_on_both_witnesses()
This is needed for a linter to check that a macro is present, see the test.
Reviewed By: skcho
Differential Revision: D18735988
fbshipit-source-id: a3be75c5e
Summary:
This gets rid of false positives when something invalid (eg null) is
passed by reference to an initialisation function. Havoc'ing what the
contents of the pointer to results in being optimistic about said
contents in the future.
Also surprisingly gets rid of some FNs (which means it can also
introduce FPs) in the `std::atomic` tests because a path condition
becomes feasible with havoc'ing.
There's a slight refinement possible where we don't havoc pointers to
const but that's more involved and left as future work.
Reviewed By: skcho
Differential Revision: D18726203
fbshipit-source-id: 264b5daeb
Summary:
It's a well-known fact that pulse should know too. To avoid splitting
the abstract state systematically, only act if we know the pointer is
exactly 0 to avoid reporting a nullptr dereference on `free(x)`.
Reviewed By: ezgicicek
Differential Revision: D18708575
fbshipit-source-id: 1cc3f6908
Summary:
Turns out code uses atomics in important places, modelling it removes
FPs.
The tests are copied from biabduction and adapted and extended a bit. I
didn't implement compare_exchange primitives for now (plus, giving them
a sequential semantics like in biabduction is probably a bit cheeky).
Reviewed By: skcho
Differential Revision: D18708576
fbshipit-source-id: a3581b8a4
Summary: This extends semantics of binary operator for BoItv. If there is no known interval value for a pulse value, it returns a symbolic value of the pulse value.
Reviewed By: jvillard
Differential Revision: D18726768
fbshipit-source-id: ed8ecf78b
Summary:
This diff adds inferbo's interval values to pulse's attributes. The added values will be used to
filter out infeasible passes in the following diffs.
Reviewed By: jvillard
Differential Revision: D18726667
fbshipit-source-id: c1125ac6e
Summary:
This will make our analysis more precise. E.g. in the future we can classify
"condition redundand" warnings by origin, and warn only for
InferredNonnull, or autogenerate fixes based on the origin.
Error messaging does not currently take into account origin for nonnull
types, but this can be changed in the future
Reviewed By: ngorogiannis
Differential Revision: D18685304
fbshipit-source-id: 6a1f263f5
Summary: The debugger in the middle of the evaluation makes working on that file difficult. Separating modules a bit, so that we can change the code easier. This is in preparation to trying to add aliases and witnesses to formulas in a next diff.
Reviewed By: jvillard
Differential Revision: D18708542
fbshipit-source-id: 523f30fc9
Summary: The tableaux evaluation was an experiment and it was turned off because of bad perf. Let's kill it to clear up the code.
Reviewed By: jvillard
Differential Revision: D18708388
fbshipit-source-id: 099f5a3d3
Summary:
This diff fixes the model of substring.
Problem: The cost model of the substring function was to return `size of string - start index` as a
cost. However, sometimes this was a negative number, because of state abstractions on paths, array
elements, call contexts, etc, which caused an exception inadvertently.
This diff changes the model to return just `size of string`, when it cannot say `size of string` is
bigger than `start index`.
Reviewed By: ezgicicek
Differential Revision: D18707954
fbshipit-source-id: 63f27e461
Ezgi Çiçek
Sungkeun Cho
Nikos Gorogiannis
Jules Villard
Dulma Churchill
Martin Trojer
Mitya Lyubarskiy
Josh Berdine
Artem Pianykh