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 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 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
Summary:
Instead of trying to figure out what runnable is directly passed to an executor,
use attributes to track the flow of a runnable. This has several advantages:
- Can track runnables across function return values.
- Can somewhat overcome the information loss under dynamic dispatch.
- Unifies handling with other attributes.
Reviewed By: skcho
Differential Revision: D18672676
fbshipit-source-id: a06a0e6ff
Summary:
- Unify treatment of modelled and annotated executors by making things go through attributes.
- Add a return attribute to summaries, so that we can track flows of thread guards/executors/future stuff through returned values.
- Dispatch modeled functions to model summaries.
This will help in following diffs where runnables will also go through attributes.
Reviewed By: skcho
Differential Revision: D18660185
fbshipit-source-id: e26b1083e
Summary:
A plugin update allows infer to know when a function doesn't return
according to its attributes. This propagates this info all the way to
the attributes of each function, and then use this information in a new
pre-analysis that cuts the links to successor nodes of each `Call`
instruction to a function that does not return.
NOTE: The "no_return" `CallFlag.t` was dead code, following diffs deal
with that (by removing it).
Reviewed By: dulmarod
Differential Revision: D18573922
fbshipit-source-id: 85ec64eca
Summary:
This also prints the CFGs *after* pre-analysis for individual procedures
in infer-out/captured/<filename>/<proc>.dot. One can also look up the
CFGs before pre-analysis in infer-out/captured/proc_cfgs_frontend.dot.
Context: I want to add a pre-analysis that needs to look at proc
attributes inter-procedurally. For this to make sense it has to happen
*after* all of capture, and before analysis.
Thus, this diff brings back the lazy running of the pre-analysis like in
D15803492, except that we still make sure to run the pre-analyses
systematically regardless of the checkers being run by running the
pre-analysis from ondemand.ml. Also we don't need to re-introduce the
"did_preanalysis" proc attribute for the same reason that the
pre-analysis is now run once and for all by ondemand.ml (instead of each
individual checker back in the days).
This has the benefit of running the pre-analysis only when needed, and
the drawback that several concurrent processes analysing the same proc
descs will duplicate work. Since pre-analyses are supposed to be very
fast I assume that neither is a big deal. If they become more expensive
then the benefit gets bigger and the drawback is just the same as with
regular analyses.
Reviewed By: skcho
Differential Revision: D18573920
fbshipit-source-id: de350eaef
Summary: This diff get static value with `EMPTY` field from class initializer.
Reviewed By: ngorogiannis
Differential Revision: D18616588
fbshipit-source-id: 26414c9b2
Summary: When we see a call to schedule some work on an executor and we don't have evidence that it is on some specific thread (UI/BG), instead of dropping the work, assign it `UnknownThread` and treat it as running on the background by default.
Reviewed By: jvillard
Differential Revision: D18615649
fbshipit-source-id: e8bad64b6
Summary: Following D18351867, this diff adds more size alias: when initial array size is one.
Reviewed By: ezgicicek
Differential Revision: D18530598
fbshipit-source-id: 26d57fe30
Summary:
- more flexible API
- less error-prone thanks to named parameters
- also takes care of adjusting predecessors of the previous successors!
This fixes some (probably harmless) bugs in the frontends.
Reviewed By: dulmarod
Differential Revision: D18573923
fbshipit-source-id: ad97b3607
Summary: The transition HOLDS-NEXT WITH-TRANSITION Parameters was only implemented for ObjC methods, now it also works on function calls.
Reviewed By: jvillard
Differential Revision: D18572760
fbshipit-source-id: 06e615cbe
Summary:
Now we point to the root cause of the problem, and also provide
actionable way to solve the issue
Reviewed By: artempyanykh
Differential Revision: D18575650
fbshipit-source-id: ba4884fe1
Summary:
Two goals:
1. Be less assertive when speaking about third party code (it might be
written with different conventions).
2. Point to third party signatures folder so the users know how to
proceed
Reviewed By: artempyanykh
Differential Revision: D18571514
fbshipit-source-id: 854d6e746
Summary:
1/ We now support messaging for third-party: show file name and line
number
2/ We did not show information about internal models in case of param
calls
3/ Small change: we don't specify "modelTables.ml" anymore: no need to
expose implementation details
Reviewed By: artempyanykh
Differential Revision: D18569790
fbshipit-source-id: 28586c8ff
Summary:
Whole bunch of changes aimed to make error messages more clear and
concise.
1/ Wording and language is unified. We make errors sound more like a
type system violations, rather than linter reccomendations.
Particularly, we refrain from saying things like "may be null" - this is
a linter-style statement that may provoke discussions (what if the
developer knows it can not be null in this particular case).
Instead, we refer to declared nullability and nullability of actual values. This way, it is more clear that this is not a heuristic, this is how rules of a type-system work.
2/ Additionally, we drop things like field class in places when the
context should be clear by who looks at the error. We expect the user
sees the code and the error caption. So e.g. we don't repeat the word "field"
twice.
3/ In cases when we are able to retrieve formal param name, we include it for
usability.
4/ For Field not initialized error, we refer to Initializer methods:
this is a non-obvious but important nullsafe feature.
Reviewed By: artempyanykh
Differential Revision: D18569762
fbshipit-source-id: 9221d7102
Summary:
It make the message bit less heavy, and also it is kind of obvious that
it is origin.
In follow up diffs we will change the text so it is hopefully even more
obvious.
Reviewed By: artempyanykh
Differential Revision: D18527695
fbshipit-source-id: a305d547b
Summary:
1. We don't want to teach the users to ignore noise origin because
sometimes we are going to render something useful for them.
2. It just looks not cool.
Reviewed By: artempyanykh
Differential Revision: D18527694
fbshipit-source-id: 0ea248122
Summary: Android may spontaneously call these methods on the UI thread, so recognize the fact.
Reviewed By: ezgicicek
Differential Revision: D18530477
fbshipit-source-id: a8a798779
Summary:
First step towards a global analysis. A new command line flag activates the step in `Driver`.
The whole-program analysis is a simple, quadratic (inefficient-as-yet), iteration over all domain elements. However, it is restricted to those elements that are explicitly scheduled to run.
Reviewed By: skcho
Differential Revision: D17787441
fbshipit-source-id: 9fecd766c
Summary:
Note: Disabled by default.
Having some support for values, we can report when a null or constant
value is being dereferenced. The particularity here is that we don't
report when 0 is a possible value for the address, or even if we know
that the value of the address can only be 0 in that branch! Instead, we
allow ourselves to report only when we the address has been *set* to
NULL (or any constant).
This is in line with how pulse deals with other issues: only report when
1. we see an address become invalid, and
2. we see the same address be used later on
Reviewed By: skcho
Differential Revision: D17665468
fbshipit-source-id: f1ccf94cf
Summary:
This diff avoids unqualified variables by `ItvUpdatedBy` are qualified later. For example,
```
z = x & y;
z = z + 1;
```
While `z` should not be selected as a control variable, it wasn't, because it was qualified by the addition. This pattern introduces FPs in many cases.
Reviewed By: ngorogiannis
Differential Revision: D18505894
fbshipit-source-id: 13aec3008
Summary:
This diff excludes integer variables from control variables when their values are calculated by
binary operators.
Reviewed By: ezgicicek
Differential Revision: D18505826
fbshipit-source-id: 710533d4c
Summary: Adding a trace that includes when strongSelf was assigned to, and when it's used without a check.
Reviewed By: skcho
Differential Revision: D18506113
fbshipit-source-id: 778c4b086
Summary:
The variable strongSelf, because it is equal to a weak captured pointer, needs to be checked for null before being used, otherwise it could be null by the time the block is executed.
Added this check to the SelfInBlock checker, and removed it from biabduction.
We want to migrate all the objc checks from biabduction, so it will be easier to change and faster and more reliable. Moreover, this check is more general, it will flag any use of unchecked strongSelf, not just a dereference.
Reviewed By: skcho
Differential Revision: D18403849
fbshipit-source-id: a9cf5d80b
Summary:
There was a precision loss during the substitution of array block. For example:
Callee's abstract memory includes an array block as follows, where `a` is a parameter.
```
a.elements -> { a.elements[*] with a.elements.size }
```
Callers' abstract memory includes a pointer that may point to multiple array blocks.
```
c -> { x, y }
x.elements -> { x.elements[*] with x.elements.size }
y.elements -> { y.elements[*] with y.elements.size }
```
When the callee is called with the parameter `c`, the callees memory is substituted to:
```
x.elements -> { x.elements[*] with top , y.elements[*] with top }
y.elements -> { x.elements[*] with top , y.elements[*] with top }
```
because `a.elements[*]` was substituted to `{ x.elements[*] , y.elements[*] }`
and `a.elements.size` was substituted to `top ( = x.elements.size join y.elements.size )`.
This diff tries to keep the precision in the specific case, not to join the sizes of array blocks.
So now the same callee's abstract memory is substituted to:
```
x.elements -> { x.elements[*] with x.elements.size }
y.elements -> { y.elements[*] with y.elements.size }
```
Reviewed By: ngorogiannis
Differential Revision: D18480585
fbshipit-source-id: b70e63c22
Summary: Due to the weakness of the analysis which can't detect side-effecting prop setting (e.g. as in `builder.prop1(..)`), we currently have many broken chains that do do have any `create` method in their prefixes. Let's not report on these broken chains.
Reviewed By: skcho
Differential Revision: D18503523
fbshipit-source-id: 7506e34b7
Summary:
In some apps executors are obtained by calling standard framework methods (and not by using DI with annotations).
To treat this style, we need to
- Detect calls that return such executors (`do_executor_effect`) and tag the return result with an `Attribute` indicating that it is now an executor, plus what thread it uses.
- Use that information when calling `execute`, to resolve the executor, if any, and its thread (in `do_work_scheduling` via `AttributeDomain.get_executor_constraint`).
- All this requires a new domain component, mapping variables to attributes. This extends the component previously used for remembering whether a variable is the result of a check on whether we run on the UI thread.
At the same time, I un-nested some functions from the transfer function for readability.
Reviewed By: skcho
Differential Revision: D18476122
fbshipit-source-id: bc39b5c2f
Summary:
We consider Java collections to be like c++ std::vectors and add models for
- `Collections.get(..)`
- `__cast`
Reviewed By: skcho
Differential Revision: D18449607
fbshipit-source-id: 448206c84
Summary: `equals1` and `equals2` in `SafeInvertedMap.join` are references that indicate whether given parameters and the result is physically equal or not. This diff fixes a missing update of them.
Reviewed By: ezgicicek
Differential Revision: D18450680
fbshipit-source-id: bae19cbe9
Summary:
It returns non-top value when one of the parameters of band is positive, i.e., `x & 255` returns
`[0, 255]` instead of top.
Reviewed By: ezgicicek
Differential Revision: D18448614
fbshipit-source-id: aaa298a66
Summary:
Let's introduce a set of new cost analysis issue types that are raised when the function is statically determined to run on the UI thread. For this, we rely on the existing `runs_on_ui_thread` check that is developed for RacerD. We also update the cost summary and `jsonbug.cost_item` to include whether a method is on the ui thread so that we don't repeatedly compute this at diff time for complexity increase issues.
Note that `*_UI_THREAD` cost issues are assumed to be more strict than `*_COLD_START` reports at the moment. Next, we can also consider adding a new issue type that combines both such as `*_UI_THREAD_AND_COLD_START` (i.e. for methods that are both on cold start and run on ui thread).
Reviewed By: ngorogiannis
Differential Revision: D18428408
fbshipit-source-id: f18805716
Summary:
This diff tries more narrowing during analysis in order to get preciser results on nested loops.
In the widening phase, it does narrowing a loop right after its widening, for each loops. In general, this may make the widening phase non-terminating because it keeps the abstract state from monotonely increasing to the fixed point in a finite number of iterations. To avoid that situation, this diff applies the narrowing only when the first visit of the loop in the widening phase.
Reviewed By: ngorogiannis
Differential Revision: D18400631
fbshipit-source-id: cc76f7e85
Summary: Sometimes there is a code like `for(int i = 1; i < x; i++){ l.add(); }`, where the first element in a list is addressed specifically. This case was not analyzed precisely, because the alias value is added only when `i` is initialized by 0 by heuristic. This diff extends the heuristic, so it adds a size alias between `i` and `l.size()` when `i` is initialized by 0 or 1.
Reviewed By: ezgicicek
Differential Revision: D18351867
fbshipit-source-id: e7d19a4ec
Summary:
This diff adds semantics of Java function calls of enum `values` inside class initializers.
* Java class initializer function initializes a specific field `$VALUES`, which points to the list
of enum values.
* The `values` function of enum class returns the value of `$VALUES`.
The problem is when the `values` function is called inside the class initializer, for example:
```
enum Color {
RED,
GREEN,
BLUE;
static {
for (Color c : Color.values()) {}
}
}
```
This introduces a recursive dependency: the class initializer calls `Color.values` and the function
returns `Color.$VALUES` the value of which should be initialized in the class initializer.
To address the problem, this diff finds the value of `$VALUES` in its abstract memory when
`values` is called inside the class initializer.
Reviewed By: ezgicicek
Differential Revision: D18349281
fbshipit-source-id: 21766c20f
Jules Villard
Sungkeun Cho
Dulma Churchill
Mitya Lyubarskiy
Nikos Gorogiannis
Martin Trojer
Ezgi Çiçek