Summary: The transition function was using a complicated-looking and possibly-inefficient pattern of options for everything, when simple pattern matching with guards is sufficient.
Reviewed By: skcho
Differential Revision: D21179606
fbshipit-source-id: a37f97594
Summary: Specialise the above option to `true` and remove resulting dead code.
Reviewed By: dulmarod
Differential Revision: D21177041
fbshipit-source-id: 4a1c65850
Summary: Java has this pattern of wrapping non-thread-safe containers in factory methods producing identically-typed results, but wrapped in a synchronised shell. This diff teaches RacerD about some common factory methods and uses the attribute domain to track the dynamic type of their results.
Reviewed By: ezgicicek
Differential Revision: D21155538
fbshipit-source-id: 42ebe6251
Summary: Complete the set of models for java containers that Infer should not report thread safety violations.
Reviewed By: ezgicicek
Differential Revision: D21138280
fbshipit-source-id: 01e1944b6
Summary: Models were partial and/or simply missing (`Map` writes!). Now the modelled containers use inheritance for conciseness (`List` reads are only those not caught by the `Collection` matcher, etc). Also, add URLs to documentation sources.
Reviewed By: ezgicicek
Differential Revision: D21132069
fbshipit-source-id: fefb360f0
Summary:
One source of false positives on container races is when the container member field is initialised to a concurrent version in a constructor, but the static type of the field doesn't reflect the thread safety of it.
This solution
- tracks flows from constructors of safe data structures to abstract addresses;
- initialises the initial attribute state when analysing a non-constructor method to that achieved by all constructors/class-initializers.
- checks for that attribute when recording container accesses.
Reviewed By: jvillard
Differential Revision: D21089428
fbshipit-source-id: 02a88f6e8
Summary:
Now that only races rooted at formals or globals are reported, there is no point using the ownership domain to exclude accesses to locals, so remove the code that initialises the ownership of those.
Also, remove an accidentally quadratic use of `Map.bindings |> List.find` in `FormalMap` and simplify the analysis driver.
Reviewed By: skcho
Differential Revision: D21066855
fbshipit-source-id: 126080778
Summary: Move state to summary conversion into the domain file, move a model matcher into the models file and simplify.
Reviewed By: skcho
Differential Revision: D21064351
fbshipit-source-id: bb5b07b6b
Summary:
The full inventory of everything in infer-out/. The main change is
around "issues directories": instead of registering them dynamically
they are now all declared statically (well, they kind of were already in
Config.ml).
Reviewed By: ngorogiannis
Differential Revision: D20894305
fbshipit-source-id: 1a06ec09d
Summary:
Fix all the docstrings that `odoc` or `ocamlformat` is not happy about.
Delete all `[@@ocamlformat "parse-docstring = false"]` pragmas as a
result.
Reviewed By: jberdine, ngorogiannis
Differential Revision: D20798913
fbshipit-source-id: 728d9e45c
Summary:
`IssueLog` is used by the file-level analysis callbacks to store reports outside error logs so as to avoid racing on spec files. Each file should generate a single issue log which is then written to an appropriate file. The starvation checker was breaking that contract because it ostensibly needs to write out multiple issue files when analysing a single source file.
This is unnecessary, because the existing mechanisms for deduplication ensure only one issue file needs to be written out.
The whole-program mode still needs that capability, but this is implemented outside the file-analysis callback.
Reviewed By: mityal
Differential Revision: D20736135
fbshipit-source-id: 620e5484d
Summary:
The text is ambiguous because it sounds as if it recommends annotating the current class as `ThreadSafe`, not the interface invoked.
Also, remove the not useful part "or using an interface known to be thread-safe" because developers don't know in general what interfaces Infer thinks are thread-safe.
Reviewed By: skcho
Differential Revision: D20675729
fbshipit-source-id: 9da438621
Summary:
Morally, INTERFACE_NOT_THREAD_SAFE is issued when an interface method is invoked from `ThreadSafe`-annotated code on an interface that is not known to be thread-safe or annotated so.
However, the ultimate purpose is to prevent races. Thus it should never be issued on an owned object or on objects we would not report races on for any reason (local variables, non-source variables, etc).
This diff equips interface call records with the abstract address they are invoked on, and uses the same rules for maintaining those records or not.
Reviewed By: skcho
Differential Revision: D20669259
fbshipit-source-id: 6c7841e6a
Summary:
For historical reasons, the record of an access is a three-level record:
1. `AccessSnapshot`, a record with info such as ownership and lock status, including
2. `TraceElem`, a record with a trace and an element which is
3. Access, the abstract addressed accessed and the type of access.
This stack flips the order to 2, 1, 3, leading up to the possibility of merging 1 and 3.
This diff improves the domain interface and consolidates all the various validity invariant checking for accesses inside their constructors.
Reviewed By: skcho
Differential Revision: D20668611
fbshipit-source-id: 45806d40d
Summary:
For historical reasons, the record of an access is a three-level record:
1. `AccessSnapshot`, a record with info such as ownership and lock status, including
2. `TraceElem`, a record with a trace and an element which is
3. Access, the abstract addressed accessed and the type of access.
This stack flips the order to 2, 1, 3, leading up to the possibility of merging 1 and 3.
This diff inverts 2 and 1.
Reviewed By: skcho
Differential Revision: D20644100
fbshipit-source-id: 89d810b68
Summary:
For historical reasons, the record of an access is a three-level record:
1. `AccessSnapshot`, a record with info such as ownership and lock status, including
2. `TraceElem`, a record with a trace and an element which is
3. `Access`, the abstract addressed accessed and the type of access.
This stack flips the order to 2, 1, 3, leading up to the possibility of merging 1 and 3.
This diff introduces functions in (1) that mask calls to (2), making the flip easier.
Reviewed By: skcho
Differential Revision: D20619614
fbshipit-source-id: 19fda0916
Summary: There are no plans currently to track which lock protects each access, so reduce to the functional equivalent of having a singleton lock domain.
Reviewed By: skcho
Differential Revision: D20595013
fbshipit-source-id: d5100ac49
Summary:
This function is used to adapt the callee summary at a call site. It did two things for every domain element in the callee summary:
- A linear search through the list of actuals.
- For each such actual, it would (repeatedly) compute its ownership (!).
For large summaries this can be substantial. The right way is to precompute the ownership for all actuals once and then simply retrieve it (via an array).
Reviewed By: jberdine
Differential Revision: D20564447
fbshipit-source-id: 1ca3121c2
Summary: The attribute types present are exclusive, so sets are not needed for the attribute map domain. This changes `Attribute` to a flat domain and removes the set on top of that.
Reviewed By: jberdine
Differential Revision: D20560240
fbshipit-source-id: 83e59d73e
Summary:
Both modules define properties the analysis maps to addresses, there is no reason to have two modules for this.
Also remove an instance of `Caml.Not_found` usage.
Reviewed By: jberdine
Differential Revision: D20558683
fbshipit-source-id: eacafd780
Summary: There has never been a sufficient formal basis for soundness nor completeness of reports on locals. This diff changes the domain to effectively concern only expressions rooted at formals or globals.
Reviewed By: ezgicicek
Differential Revision: D19769201
fbshipit-source-id: 36ae04d8c
Summary:
# Current design
Infer analysis is currently two staged:
1) proc-level callbacks calculate summary, including writing down the
issues if applicable.
2) file-level callbacks (formerly cluster callbacks, see the prev diff) are executed next; they are supposed to emit
additional issues that are impossible to emit based on mere
proc-context.
Currently RacerD and Starvation use file-level callback; in near future
we plan to onboard Nullsafe checker as well.
# Problem
Contract of callback (1) is clear: given a proc and existing
summary, the checker updates it and returns a modified summary. This
summary later on gets serialized (in-memory + external) and can be consumed by
other chechers. Issues written in summary will get reported when
analysis is over.
In constrast, contract of (2) is wild west: the function returns unit.
In practice, what the checkers do is create IssueLog and serialize it to
checker-specific directory.
Then another part of program (InferPrint.ml) knows about this side
effect, reads the error log for checkers and ultimately get it reported
together with errors written at stage (1).
This is problematic because it is hard to reason about the system and it
makes onboarding new checkers to (2) error-prone.
# This diff
This diff brings (2) on par with (1): now file-level callback has a
clear contract: it should be side effect free, and the only
responsibility is to fill out and return IssueLog.
Additionally, we make the notion of "checker-specific issue directory"
an official thing, so the checker only needs to specify the name,
everything else will be made automatically by orchestation layer,
including cleanup.
# Starvation
Implementing the new contract is starvation is possible and desirable, but involved: see comment
in the code, so we leave it up to the future work to fix that.
Reviewed By: ngorogiannis
Differential Revision: D20115024
fbshipit-source-id: fb2f9b7e6
Summary:
1. Some invariants are tricky enough to be documented. This is especially
important for cases related with error reporting. Lets document it.
2. Cluster callback -> File callback rename.
Reviewed By: ngorogiannis
Differential Revision: D20093932
fbshipit-source-id: e716f1f5b
Summary:
Previous implementation supported only stringy params (strings and
stringified bools). Current one exposes a proper variant `Annot.t`,
with support for all possible param values in Java except
numbers (more on that below).
This change is required for implementing `Nullsafe(LOCAL)` as the
annotation used to specify nullsafe behaviour has a more complex
structure than what we've dealt with before.
**Why support for number values was not added**: supporting numbers
requires using `int64`. Unfortunately, adding another variant `Vnum
int64` to `Annot.t` causes a runtime failure on assert in
`MaximumSharing.ml:133`. It seems that it might be enough to flip
`fail_on_nonstring` from `true` to `false`, but since this would
require additional testing and is not required for my case, I'll leave
checking this to whoever needs to use numeric annot params in future.
Reviewed By: ezgicicek
Differential Revision: D19855923
fbshipit-source-id: 878e33856
Summary:
The big one:
- stop using polymorphic `<>`, `<`, `>`, ..
- add `<>` to `PolyVariantEqual` escape hatch now that `<>` is as taboo as `=`
- Interestingly, there were a lot of uses of `Z.(x < y)`, which although
they seem to use `Z.lt` actually used polymorphic comparison. The actual
comparison infix operators of `Z` are cleverly hidden in `Z.Compare`
instead, which makes them impractical to use...
Reviewed By: jberdine
Differential Revision: D19861584
fbshipit-source-id: 5dce08ad9
Summary:
The domain has a notion of lock state (taken/not taken) and any access occurring will remember the current lock state.
Methods in Java can be `synchronized` meaning the lock is taken automatically at method start and release on return.
Currently, instead of starting analysis of a `synchronized` method with an initial lock state of "lock taken", the summary would be computed as if there is no lock, and then a caller would peek at whether the callee is `synchronized` and change the callee summary accordingly before taking it into account. Also, when an access happens (not a call) the analysis always consults the pdesc of the current method to check whether the method is `synchronized`.
Do things the right way: if method is `synchronized`, start with the lock taken. When the method exits, the lock-state postcondition is computed by releasing once the lock.
This is a behaviour-preserving change.
Reviewed By: mityal
Differential Revision: D19742559
fbshipit-source-id: 1d0fce3f6
Summary:
The goals are:
- Increase precision in C-languages by ditching access paths.
- Help with eventually sharing the abstract address module with RacerD.
- Reports are now language-mode specific (eg `->` in clang vs `.` in Java).
It's not exactly access expressions used here. Instead the pattern `(base, access list)` is used where `access` is `HilExp.Access.t`. This is done to ease the way `deriving` is used for creating two comparison functions, one that cares about the root variable and one that doesn't; and also because the main function that recurses over accesses (`normalise_access_list`) visits the accesses from innermost to outermost.
Also, kill some dead code.
Reviewed By: skcho
Differential Revision: D19741545
fbshipit-source-id: 013bf1a89
Summary:
The problem with is_override that it can be misleading: it does not
check that that class of the first method is a subtype of the second; in
fact it totally ignores the classes.
This method is publicly exposed so lets just call what it does.
Reviewed By: jvillard
Differential Revision: D19724295
fbshipit-source-id: dc0919193
Summary:
To emulate the `ThreadSafe` contract in C++/ObjC, reporting was gated behind a check that ensured a C++/ObjC class has a `std::mutex` member (plus other filters). This is reasonable, but it has some drawbacks
- other locks may be used, and therefore must be added to the member check;
- locking mechanisms that use the object itself as a monitor cannot be modelled (`synchronized` in ObjC)
RacerD already has `ThreadsDomain` which models our guess on whether a method is expected to run in a concurrent context, and which in C++/ObjC boils down to whether the method non-transitively acquires a lock. This should be a good enough indicator that the class should be checked regardless of whether the locks are member fields. This diff gates the C++/ObjC check on that abstract property.
Reviewed By: dulmarod
Differential Revision: D19558355
fbshipit-source-id: 229d7ff82
Summary:
- Thread the two types into one instead of having a record where the `path` field doesn't always make sense (`Class` case).
- Improved pretty printing of class objects (java only).
- Move starvation-specific stuff out of `AbstractAddress` (eg `make_java_synchronized`).
- Slight optimisation of `apply_subst` for when a parameter is used without additional accesses inside a method (then, the substitution need not modify the term substituted for the parameter in any way).
Reviewed By: ezgicicek
Differential Revision: D19639922
fbshipit-source-id: 1cebecf5d
Summary: This will be eventually used in RacerD. Further diffs up the stack will migrate away the starvation-specific aspects.
Reviewed By: ezgicicek
Differential Revision: D19623392
fbshipit-source-id: a72650718
Summary:
The "access path" memory model (equal access paths iff equal object addresses) is suited to when aliasing occurs only at the roots (i.e. variables). When there is intentional aliasing in the middle of an access path, this model will miss the aliasing. For instance if `[x.f] == [y.g]`, then also `[x.f.h] == [y.g.h]`, but the latter access paths are unequal.
In Java, non-static inner classes consistently alias `this.this$0` inside an inner class, which points to the "parent" outer-class object. So if two inner-class objects (belonging to different inner classes) access `this(type:InnerClassA).this$0.f` and `this(type:InnerClassB).this$0.f` the equality will be missed (many other combinations exist). This isn't strictly due to the memory model -- any alias analysis would have to do some class invariant inference to detect this.
For this purpose `AccessPath.inner_class_normalize` exists (it replaces `this.this$0` with `this` of the appropriate type), but this breaks the invariant that we know which formal parameter is at the root (there may not even exist a `this` parameter if the method is static). So this was buggy.
Here we simply recursively remove the synthetic field prefix of the accesses list, while computing forwards the object type. This is only applied when we check aliasing across threads. This will also allow actuals/parameters substitutions (stacked diff) which normalisation was breaking.
Reviewed By: jberdine
Differential Revision: D19601455
fbshipit-source-id: 7e42667b6
Summary: Keep the type name of the class as the key in the map constructed from class names to their methods in a file. This will be used later, and also why string?
Reviewed By: dulmarod
Differential Revision: D19557707
fbshipit-source-id: aa8569581
Summary: Currently, empty summaries are passed to the cluster callbacks. This is pointless and could potentially lead to recomputing already analysed summaries. This change passes only procnames to the callback, and `Ondemand` is used to load the summary or analyse as needed.
Reviewed By: jvillard
Differential Revision: D19544043
fbshipit-source-id: 28ab642c3
Summary: There is no need to provide type environments to cluster analysers, since the execution environment can be used to retrieve those on demand.
Reviewed By: jvillard
Differential Revision: D19543561
fbshipit-source-id: f9b064011
Summary: Deadlocks often result in two reports if not deduplicated (two traces), so there is some logic for doing that. Locks recently became an opaque type, with the `get_access_path` loophole supporting that deduplication ordering. Fix that here and remove `Lock.get_access_path`.
Reviewed By: jvillard
Differential Revision: D19465223
fbshipit-source-id: b597e3c65
Summary: Change `MayBlock` and `StrictModeCall` constructors from taking a string to a `Procname.t`, which was the sole source of that string anyway.
Reviewed By: ezgicicek
Differential Revision: D19465226
fbshipit-source-id: e3ed6ef88
Summary:
If a race exists in two or more overloads of the same method and we use only the class and method name in the report text, then the current bug hashing algorithm will identify the two reports as duplicates.
To avoid this, the report had the class, method and list of type parameters. This is unreadable, however, and redundant (the report is already located within the method in question). So at the risk of duplicates, use only class+method names.
Also, fix a bug in `Procname.pp_simplified ~withclass` where `withclass` was ignored for C++/ObjC methods.
Now:
> Read/Write race. Non-private method `FrescoVitoImageSpec.onCreateInitialState(...)` indirectly reads with synchronization from `factory.AnimatedFactoryProvider.sImpl`. Potentially races with unsynchronized write in method `FrescoVitoImageSpec.onEnteredWorkingRange(...)`.@ [Litho components are required to be thread safe because of multi-threaded layout](https://fburl.com/background-layout). Reporting because current class is annotated `MountSpec`, so we assume that this method can run in parallel with other non-private methods in the class (including itself).
Before
> Read/Write race. Non-private method `void FrescoVitoImageSpec.onCreateInitialState(ComponentContext,StateValue,StateValue,Uri,MultiUri,ImageOptions,FrescoContext,Object,ImageListener)` indirectly reads with synchronization from `factory.AnimatedFactoryProvider.sImpl`. Potentially races with unsynchronized write in method `FrescoVitoImageSpec.onEnteredWorkingRange(...)`.@ [Litho components are required to be thread safe because of multi-threaded layout](https://fburl.com/background-layout). Reporting because current class is annotated `MountSpec`, so we assume that this method can run in parallel with other non-private methods in the class (including itself).
Reviewed By: artempyanykh
Differential Revision: D19462277
fbshipit-source-id: aebc20d89
Summary:
Introduce a new notion of equality for comparing abstract addresses in distinct threads:
```
(** Abstract address for a lock. There are two notions of equality:
- Equality for comparing two addresses within the same thread/process/trace. Under this,
identical globals and identical class objects compare equal. Locks represented by access paths
rooted at method parameters must have equal access paths to compare equal. Paths rooted at
locals are ignored.
- Equality for comparing two addresses in two distinct threads/traces. Globals and class objects
are compared in the same way, but locks represented by access paths rooted at parameters need
only have equal access lists (ie [x.f.g == y.f.g]). This allows demonically aliasing
parameters in *distinct* threads. This relation is used in [may_deadlock]. *)
```
Reviewed By: skcho
Differential Revision: D19347307
fbshipit-source-id: 9f338731b
Summary: Access expressions can appear in casts, or sometimes other constructors, inside a `HilExp.t`. Extraction of the access expression can ignore those wrappers. Introduce a single function for doing that throughout the analyser.
Reviewed By: ezgicicek
Differential Revision: D19410673
fbshipit-source-id: a724cb466
Summary: In whole-program mode, analysing a method requires analysing first all constructors of the same class. This is not needed in normal mode, so gate that computation under `starvation_whole_program` for efficiency.
Reviewed By: artempyanykh
Differential Revision: D19393412
fbshipit-source-id: 2277e6b5e
Summary: Now that we have the kind of lock stored (global/class obj/path rooted at parameter), use it for comparison/equality, while ignoring the root variable of the access path, which is only used for printing.
Reviewed By: skcho
Differential Revision: D19346801
fbshipit-source-id: c65661dc6
Summary: Add command line option that directs racerd to treat all return values from unknown code (including abstract methods) as owned objects. This is essentially treating return values with full angelicism
Reviewed By: artempyanykh
Differential Revision: D19368375
fbshipit-source-id: 6a10153fa
Nikos Gorogiannis
Jules Villard
Ezgi Çiçek
Mitya Lyubarskiy
Artem Pianykh