Summary:
Instead of the non-sensical piecewise join we had until now write
a proper one. Hopefully the comments explain what it does. Main one:
```
(* high-level idea: maintain some union-find data structure to identify locations in one heap
with locations in the other heap. Build the initial join state as follows:
- equate all locations that correspond to identical variables in both stacks, eg joining
stacks {x=1} and {x=2} adds "1=2" to the unification.
- add all addresses reachable from stack variables to the join state heap
This gives us an abstract state that is the union of both abstract states, but more states
can still be made equal. For instance, if 1 points to 3 in the first heap and 2 points to 4
in the second heap and we deduced "1 = 2" from the stacks already (as in the example just
above) then we can deduce "3 = 4". Proceed in this fashion until no more equalities are
discovered, and return the abstract state where a canonical representative has been chosen
consistently for each equivalence class (this is what the union-find data structure gives
us). *)
```
Reviewed By: mbouaziz
Differential Revision: D10483978
fbshipit-source-id: f6ffd7528
Summary:
Instead of propagating a partial state give up the analysis of the
function entirely on error. The state after an error is mostly
non-sensical so until we know better just giving up makes sure the
analysis remains sensible and produce fewer spurious warnings.
Reviewed By: mbouaziz
Differential Revision: D10483979
fbshipit-source-id: 171ec8469
Summary: First version of an analyzer collecting classes transitively touched.
Reviewed By: mbouaziz
Differential Revision: D10448025
fbshipit-source-id: 0ddfefd46
Summary:
`Location` was clashing with the `Location` module, so use `Address`
instead.
When invalidating an address, remember the "actor" of its invalidation,
i.e. the access expression leading to the address and the source
location of the corresponding instruction.
When checking accesses, also pass the actor responsible for the access,
so that when we raise an error we know:
1. when and why a location was invalidated
2. when and why we tried to read it after that
Reviewed By: mbouaziz
Differential Revision: D10446282
fbshipit-source-id: 3ca4fb3d4
Summary:
Model `x[y]` and `x.push_back(i)` to catch the classic bug of "take
reference inside vector, invalidate, then use again".
Reviewed By: da319
Differential Revision: D10445824
fbshipit-source-id: 21ffd9677
Summary:
Do the intersection of the heap and stack domains, and the union of the
invalid location sets. This forgets invalid locations that appear only
in one heap, unfortunately. We can start with this and improve later.
Reviewed By: mbouaziz
Differential Revision: D10445825
fbshipit-source-id: cc24460af
Summary:
New analysis in foetal form to detect invalid use of C++ objects after their
lifetime has ended. For now it has:
- A domain consisting of a graph of abstract locations representing the heap, a map from program variables to abstract locations representing the stack, and a set of locations known to be invalid (their lifetime has ended)
- The heap graph is unfolded lazily when we resolve accesses to the heap down to an abstract location. When we traverse a memory location we check that it's not known to be invalid.
- A simple transfer function reads and updates the stack and heap in a rudimentary way for now
- C++ `delete` is modeled as adding the location that its argument resolves to to the set of invalid locations
- Also, the domain has a really crappy join and widening for now (see comments in the code)
With this we already pass most of the "use after delete" tests from the
Ownership checker. The ones we don't pass are only because we are missing
models.
Reviewed By: mbouaziz
Differential Revision: D10383249
fbshipit-source-id: f414664cb
Summary:
Using debugging on uninit raised an exception. A file was opened twice and closed twice.
This happened because the two abstract interpreters (SIL, LowerHIL) conflicted.
Let's use the LowerHIL-AI directly
Reviewed By: jvillard
Differential Revision: D10126442
fbshipit-source-id: 113c9e131
Summary: Use `PerfEvent` to record the execution time of individual checkers.
Reviewed By: jeremydubreil, mbouaziz
Differential Revision: D9832102
fbshipit-source-id: 678fca155
Summary:
Callsites of `Reporting.log_error/warning` always use `Exceptions.Checkers`, let's simplify the API.
Under the hood it still creates an exception, but this can be cleaned up later.
Reviewed By: jeremydubreil
Differential Revision: D9799860
fbshipit-source-id: 6492a60b4
Summary: We had a special case for fixing false positives on constexpr implicitly captured by lambdas. However, we do not report dead stores on constexpr anymore, hence, do not need the special case anymore. Moreover, the special case was not only capturing constexpr in lambdas, but also any variables which type had `const` (see new test `capture_const_bad` which was not being reported before this diff)
Reviewed By: mbouaziz
Differential Revision: D9654848
fbshipit-source-id: 882fd2804
Summary:
It simplifies abstract memory instantiations of function calls. Now it instantiates callee memories by directly evaluating symbol paths, rather than constructing `subst_map`.
main changes are:
- no construction of `subst_map` and `trace_map`
- no symbol table in Inferbo's summary
- no `Symbol_not_found` exception (for when a required symbol was unavailable in `subst_map`)
Reviewed By: mbouaziz
Differential Revision: D9495597
fbshipit-source-id: 18cdcd6f7
Summary: We report dead store false positives in template arguments when constexpr is used. To remove the false positives, with the expense of some false negatives, we do not report dead stores on constexpr anymore.
Reviewed By: mbouaziz
Differential Revision: D9608095
fbshipit-source-id: 91b0c71c4
Summary:
Lambdas can capture references to locals of the enclosing method as long as
they are not propagated outside the method. However to keep things simple
always allow them to capture locals of the enclosing method at the price of
some false negatives.
Reviewed By: da319
Differential Revision: D8974434
fbshipit-source-id: 957ae44bd
Summary:
In SIL, (1) some program variables (e.g., array parameter) are used as pointers to heap addresses and (2) the other program variables (e.g., local array) are used as addresses themselves. So, the values of (1) are retrieved by the `Load` command, while that of (2) are by `Exp.Lvar` expressions directly.
To address them differently, we had managed two maps (`Mem.Stack` and `Mem.Heap`), but which introduced function duplications on abstract memory and increased complexity. This diff merges the two maps, and instead a location set is used for distinguishing two types of abstract locations during analysis.
Reviewed By: mbouaziz
Differential Revision: D9420388
fbshipit-source-id: 13f824850
Summary:
`Errlog` will merge similar issues (same severity, name, description) reported at the same location, so let's make sure the locaiton is mandatory.
Issues:
- errors happening in `Ondemand` still use the `State` which makes sense only for biabduction and eradicate
- a case of `NullabilitySuggest` didn't have a location, I did my best to patch it but I'm sure the location could be more precise
Reviewed By: jvillard
Differential Revision: D9332840
fbshipit-source-id: ee7898146
Summary:
Before we would convert it to string in `Reporting` and pass it to `Errlog` which would use it only to 'log events'.
I guess the reason is that there was a cyclic dependency between `Errlog` and `clang_method_kind` defined in `ProcAttributes`.
This diff:
- moves it to its own module
- defers the conversion to string
Reviewed By: jvillard
Differential Revision: D9332819
fbshipit-source-id: 43a028b61
Summary: C++17 introduce guaranteed copy elision which omits constructor calls. In ownership analysis, we depended on these constructor calls to acquire ownership. In particular, when a method returns struct, previously, a constructor was used to acquire ownership. In this diff, we acquire ownership of the returned structs directly.
Reviewed By: mbouaziz
Differential Revision: D9244302
fbshipit-source-id: ae8261b99
Summary:
To keep up with the times. Changes consist of new features and moving modules
around so shouldn't change anything on our side.
Depends on D9239803
The controller you requested could not be found.: facebook-clang-plugins
Reviewed By: da319
Differential Revision: D9239817
fbshipit-source-id: d02a2076a
Summary:
Use `ignore` instead, as this will warn if the argument is an arrow type,
unlike `let _ = ...`. This makes the code more future-proof: if an argument is
added to a function called in `let _ = f x` then the compiler will complain
instead of silently turning a value into a partial evaluation.
Also got rid of particularly irksome `let _ = <stuff returning unit> in` where I could.
Reviewed By: mbouaziz
Differential Revision: D9217176
fbshipit-source-id: 3be463405
Summary:
- changes the `Ondemand` callbacks to take the execution environment instead of a `get_proc_desc` function.
- removes all the cases passing `get_proc_desc` as parameter to use `Ondemand.get_proc_desc` instead.
Reviewed By: jvillard
Differential Revision: D9200583
fbshipit-source-id: d16c218b5
Summary: This should be functionally equivalent but removes one call to `Summary.get`
Reviewed By: jvillard
Differential Revision: D9153924
fbshipit-source-id: d49789d2f
Summary: It uses a SymbolPath map to Symbol in Inferbo's summary instead of an entry memory of callee, which is used for instantiations of the abstract memories on function calls.
Reviewed By: mbouaziz
Differential Revision: D9081631
fbshipit-source-id: 478cda0de
Summary:
It adds relational domains to Inferbo: octagon of Apron and polyhedra of Elina.
- Each Mem domain value includes one relational value containing relations among symbols. The relational values are modified by the `Prune` and `Store` commands.
- Each abstract value includes three symbols, which represent integer value, array offset, and array size of an abstract value.
The relational domain is deactivated by default. Use the `--bo-relational-domain {oct, poly}` option for the activation, though Inferbo with the relational domains does not work at this point because some modifications of Apron and Elina we made has not been applied to their opam repositories yet.
Reviewed By: jvillard
Differential Revision: D8874102
fbshipit-source-id: 08e5883cb
Summary:
It adds relational domains to Inferbo: octagon of Apron and polyhedra of Elina.
- Each `Mem` domain value includes one relational value containing relations among *symbols*. The relational values are modified by the `Prune` and `Store` commands.
- Each abstract value includes three *symbols*, which represent integer value, array offset, and array size of an abstract value.
The relational domain is deactivated by default, so this diff should not make any differences in CI.
Use `--bo-relational-domain {oct, poly}` for the activation, though Inferbo with the relational domains does not work at this point because some modifications of Apron and Elina we made has not been applied to their opam repositories yet.
Reviewed By: mbouaziz, jvillard
Differential Revision: D8478542
fbshipit-source-id: 510ff53
Summary:
The addresses of global variables do not need initialisation to exist and be valid as they are part of the code or data segment of the program. This means that taking the address of a global is not in itself a danger for SIOF. However, dereferencing such an address would be. In order to avoid false positives but avoid being too unsound, only ignore them when the address is taken only to set another global. The general case would require a more complicated abstract domain.
Fixes#866
Reviewed By: ngorogiannis
Differential Revision: D8055627
fbshipit-source-id: 92307b2
Summary:
I realized that control variable analysis was broken when we had multiple back-edges for the same loop. This is often the case when we have a switch statement combined with continue in a loop (see `test_switch` in `switch_continue.c`) or when we have disjunctive guards in do-while loops.
This diff fixes that by
- defining a loop by its loophead (the target of its backedges) rather than its back-edges. Then it converts back-edge list to a map from loop_head to sources of the loop's back-edges.
- collecting multiple guard nodes that come from potentially multiple exit nodes per loop head
In addition, it also removes the wrong assumption that an exit node belongs to a single loop head.
Reviewed By: mbouaziz
Differential Revision: D8398061
fbshipit-source-id: abaf288
Summary: Introduce an annotation that forces the summary of a method to be free of blocking events, without suppressing other reports.
Reviewed By: jeremydubreil
Differential Revision: D8276787
fbshipit-source-id: be9eed8
Summary:
`make doc` will use `jbuilder` (which in turn uses `odoc`) to generate the
documentation for infer's modules. This is useful to browse the APIs of infer
and gives a more discoverable place to host more general documentation about
infer's internals.
Besides the actual plumbing necessary to generate the docs, this diff also
- Moves the various infer/src/*/README.md to index.mld files that make it to the generated docs
- Fixes some doc comments that would anger `ocamldoc`
Closes#435
Reviewed By: mbouaziz
Differential Revision: D8314572
fbshipit-source-id: 4a5c70e
Summary: We get a lot of false positives for union types as union fields are treated as separate memory locations at the moment. For now we do not treat union fields as uninitialised.
Reviewed By: mbouaziz
Differential Revision: D8277363
fbshipit-source-id: efe5b4a
Summary:
Having the `Node` module including in the `CFG` one is confusing.
Let's keep it separate.
Reviewed By: ngorogiannis
Differential Revision: D8185754
fbshipit-source-id: 62077e6
Summary:
Change the license of the source code from BSD + PATENTS to MIT.
Change `checkCopyright` to reflect the new license and learn some new file
types.
Generated with:
```
git grep BSD | xargs -n 1 ./scripts/checkCopyright -i
```
Reviewed By: jeremydubreil, mbouaziz, jberdine
Differential Revision: D8071249
fbshipit-source-id: 97ca23a
Summary:
For now: just moving this list behind an abstract type.
Next: changing the internal representation.
Reviewed By: ngorogiannis
Differential Revision: D8140926
fbshipit-source-id: 5b959b0
Summary:
Preparing for the future change, we won't see instructions as lists but as an abstract type.
This change may be a very minor perf regression: does a few more (but bounded by a constant) instructions traversals only for the nodes involving a Printf-like function call, only for the PrintfArgs checker...
Reviewed By: jvillard
Differential Revision: D8094124
fbshipit-source-id: e2e2c5e
Summary:
We never really need the list of nodes/succs/preds, we only need to fold over them.
This will reduce garbage for computed lists like in the Exceptional CFG or the OneInstrPerNode CFG.
Reviewed By: ngorogiannis
Differential Revision: D8185665
fbshipit-source-id: d042beb
Summary:
Moving away from C++ include-based models means that we cannot reliably detect
anymore whether a file includes <iostream> or not. In order not to be too
spammy, let's always assume standard streams are initialized for now when the
include models are off.
Recent versions of libstdc++ make these models redundant so there is hope that in a
bright future the analysis of std streams initialisation will work correctly without infer
having to have its own models anyway.
Reviewed By: mbouaziz
Differential Revision: D8043467
fbshipit-source-id: d118043
Summary: We want both pointer and pointer dereference to be uninitialised at the beginning. Forgot to add the expression of type pointer when updating the analysis from access paths to access expressions.
Reviewed By: ddino
Differential Revision: D8117011
fbshipit-source-id: 534f7ef
Summary: Set arguments of pointer type as initialised for indirect function calls.
Reviewed By: mbouaziz
Differential Revision: D8097895
fbshipit-source-id: 830f568
Summary: Treat array accesses as initialised if they are passed by reference.
Reviewed By: jvillard
Differential Revision: D8071247
fbshipit-source-id: 5480e90
Summary: Use AccessExpressions instead of AccessPath in uninit analysis. This will allow us to distinguish between pointers and their dereferences.
Reviewed By: jvillard
Differential Revision: D8042359
fbshipit-source-id: 604bcbc
Summary:
Preparing for bigger changes...
- Rename `payload` field to `payloads`
- Move `payload` type to `Payloads.t`
- `SummaryPayload`s only have to implement a change on `Payloads.t` rather than `Summary.t`
Reviewed By: sblackshear
Differential Revision: D7987211
fbshipit-source-id: c9d7a74
Summary:
Before we were computing the size of an abstract state (`range`) using the `NonNegativeBound` domain but it wasn't able to express product of symbolic values.
This diff introduces a domain for that.
The range of an interval is still computed in `NonNegativeBound` but then the product is done in `TopLiftedPolynomial` so all costs end up being of that type.
The //symbols// of a polynomial are `NonNegativeBound` (so the polynomial only represent non-negative values, perfect for a cost), which handles substitution correctly, i.e. it gives zero instead of negative values.
Reviewed By: ddino
Differential Revision: D7397229
fbshipit-source-id: 6868bb7
Summary:
Attempt at a better naming scheme:
- `Specs.summary` are now `Summary.t`. The `Summary` module (replacing `Specs`) contains the summary of a procedure: the results of all the analyses, etc.
- `Summary.ml` is now `SummaryPayload.ml`. This concerns how each (AI) analysis extracts its payload from the master summary.
- Accordingly, checkers now define a `Payload` module where previously they defined a `Summary` module. The type is also cleaned up to use `t` instead of `payload`, etc.
- Cleaned up some names as a result, for instance `Specs.get_summary` -> `Summary.get`, etc.
Reviewed By: ngorogiannis
Differential Revision: D7935883
fbshipit-source-id: 1766545
Summary:
This is an attempt to make things more consistent, and maybe save some work
from the `Format` module in case flambda doesn't have our backs.
Reviewed By: jberdine
Differential Revision: D7775496
fbshipit-source-id: 59a6314
Summary:
The Cost analysis uses `Bound` for non-negative values only, let's make it a separate module (and abstract type).
This also separates the abstract domain part of `Bound` which we wanted anyway.
Depends on D7844267
Depends on D7843351
Depends on D7782184
Reviewed By: ddino
Differential Revision: D7844572
fbshipit-source-id: 0e6b620
Summary: We were wrongly using the underapproximation of `min` rather than the overapproximation
Reviewed By: ddino
Differential Revision: D7844267
fbshipit-source-id: c9d9247
Summary:
This simplifies the frontends and backends in most cases. Before this diff,
returning `void` could be modelled either with a `None` return, or a dummy
return variable with type `Tvoid`. Now it's always the latter.
Reviewed By: sblackshear, dulmarod
Differential Revision: D7832938
fbshipit-source-id: 0a403d1
Summary:
Add warning 60 (unused module) to the list of fatal warnings. Whitelisting
modules at toplevel is tricky (see inline comments) but doable.
Reviewed By: mbouaziz
Differential Revision: D7790073
fbshipit-source-id: 6f591c4
Summary:
We want instr-granular invariant maps so let's use the OneInstrPerNode CFG in the AI analyzers.
This requires specializing the TransferFunctions.
Keep using the normal CFG where we only need node-granular informations.
Depends on D7587241
Depends on D7608526
Reviewed By: sblackshear
Differential Revision: D7618320
fbshipit-source-id: 73918f0
Summary:
Upgrade ocamlformat, and base which needs to be done in sync in order to build
ocamlformat, and the other deps can come for the ride.
Reviewed By: jvillard
Differential Revision: D7663537
fbshipit-source-id: 3e90970
Summary: We already suppress race reports if the field is marked in this way; makes sense to do the same thing for these reports.
Reviewed By: ngorogiannis
Differential Revision: D7589275
fbshipit-source-id: 8f0aeab
Summary:
Now that everything can run at the same time and we have preanalyses, it can be quite hard to read debug sessions.
Here come session names!
Depends on D7607336
Reviewed By: sblackshear
Differential Revision: D7607481
fbshipit-source-id: 676af86
Summary:
Use an adhoc type for `StructuralConstraints` instead of hacky `Exp`s.
Also use a cleaner `Node.IdMap` instead of `Int.Map`.
Depends on D7586645
Reviewed By: ddino
Differential Revision: D7587241
fbshipit-source-id: f9d65bb
Jules Villard
Nikos Gorogiannis
Mehdi Bouaziz
Dino Distefano
Ezgi Çiçek
Josh Berdine
Julian Sutherland
Jeremy Dubreil
Martino Luca
Daiva Naudziuniene
Sungkeun Cho
Martin Trojer
Dulma Churchill
Sam Blackshear