Summary:
To find a method in non-abstract sub-classes, this diff applies the
same heuristics of inferbo.
* If the class is an interface: Find its unique sub-class and apply the heuristics recursively.
* If the class is an abstract class: Find/use its own summary if possible. If not found, find
one (arbitrary but deterministic) summary from its sub-classes.
* Otherwise: Find its own summary.
Reviewed By: ezgicicek
Differential Revision: D20647101
fbshipit-source-id: 2f8f3ff81
Summary: When looking at some reports I realised that adding the place where the memory becomes unreachable to the trace makes it more readable.
Reviewed By: skcho
Differential Revision: D20790277
fbshipit-source-id: d5df69e68
Summary:
The attribute `[no_return]` signifies that a function doesn't return. Previously, pre-analysis had cut the links to successor nodes of such no-return function nodes. This was intended to help with suppressing reporting on unreachable paths for some analyses. However, this results in having these nodes as dangling, with no connection to exit nodes.
This diff additionally shortcuts these no-return function nodes to exit node. This would allow us to enhance inter-procedural analyses like pulse to kepp track of paths that do not return since we will be keeping their connections at exit node rather than completely cutting them of as before. It would also allow us to assume that all paths start at the one start node and end at the one exit node (at least syntactically in the CFG).
Reviewed By: skcho
Differential Revision: D20736043
fbshipit-source-id: 0eace1bdb
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: In an intra-procedural analysis we assume that parameters passed by reference to a function will be initialized inside that function. We use the type information of an actual parameter to initialize the fields of the struct. This does not work if a function has a parameter of type void* as the actual parameters also has type void*. To solve this issue, we use type information from local variables.
Reviewed By: jvillard
Differential Revision: D20670253
fbshipit-source-id: dc9f051ef
Summary:
- Model `System.exit()` as early_exit and add a test
- Tweak message of methods that are impure due to having no pulse summary (and add a test)
Reviewed By: skcho
Differential Revision: D20668979
fbshipit-source-id: 6b5589aae
Summary: This diff avoids that an invalid interval value, e.g. [0, -1], is genrated by interval pruning.
Reviewed By: ezgicicek
Differential Revision: D20645488
fbshipit-source-id: 6516c75d1
Summary:
Hopefully no one uses this. This is in Python and we'd like to get rid
of it. Easy enough to either re-implement if needed or to be
re-implemented by a third party.
Reviewed By: ngorogiannis
Differential Revision: D20626344
fbshipit-source-id: 484022482
Summary: The current message is recommending to change `View.findViewById()` to `View.requireViewById()`, but the latter method is not supported in all API, so might lead to a crash in runtime.
Differential Revision: D20619361
fbshipit-source-id: 542746c79
Summary:
- the order of call state was wrong when printing contradiction for CItv
- add a test for impurity
Reviewed By: jvillard
Differential Revision: D20646181
fbshipit-source-id: 1c86fd0a4
Summary:
As exemplified by added tests, pulse computes an empty summary (with 0 disjuncts) whenever it discovers a contradiction which might be caused by:
- discovering aliasing in memory
- widening limited number of times in loops and concluding that loop exit conditions are never taken
However, AFAIU, it is not possible to have a function with 0 disjunct apart from such anomalities. Even a function which does nothing like `void foo(){}` has 1 disjuncts:
```
Pulse: 1 pre/post(s)
#0: PRE:
{ roots={ };
mem ={ };
attrs={ };}
POST:
{ roots={ };
mem ={ };
attrs={ };}
SKIPPED_CALLS: { }
```
The aim of this diff is to consider functions with 0 disjuncts as **impure** because most often such cases are impure, rather than actually pure.
Reviewed By: skcho
Differential Revision: D20619504
fbshipit-source-id: 3a8502c90
Summary:
Although try-with-resource is supported by nullsafe this code pattern
throws it off and make nullsafe report on a virtual **b**yte-**c**ode
variable.
Check out debug output from `TryWithResource` (or attached
visualisation of CFG):
0. node14: $bcvar2=null (on entry to try-with-resource).
1. node16: n$14=$bcvar2, but **also** PRUNE(!(n$14 == null), true). Then we go to
2. node18: do something here and in case of exception go to
3. node25->node23->node19->node20: and here we do
$bcvar2->addSuppressed(...).
Because on step 1 we refined nullability of n$14, but didn't refine
nullability of $bcvar20, on step 3 we are sure that $bcvar is null and
therefore issue an error.
Reviewed By: mityal
Differential Revision: D20558343
fbshipit-source-id: 520505039
Summary:
This is likely not the final refinement, rather one step forward.
We classify all classes by 3 categories:
- Nullsafe and 0 issues
- can add Nullsafe and will be 0 issues
- the rest (class needs improvement)
Each class will fall into exactly one category.
Error messaging is WIP, they are not intended to be surfaced to the user
just yet.
Note how this diff uses the result of the previous refactoring.
Reviewed By: artempyanykh
Differential Revision: D20512999
fbshipit-source-id: 7f462d29d
Summary: Add a flag `is-inclusive-cost` (`true` by default) which computes inclusive cost for each function. Setting the flag to `false` computes exclusive cost of the function where the cost of the callees are assumed to be `0`.
Reviewed By: skcho
Differential Revision: D20558275
fbshipit-source-id: 6b5798916
Summary:
# Problem
Consider
```
some_method(Object a) { a.deref(); }
```
What is nullability of `a` when we dereference it?
Logically, things like "LocallyCheckedNonnull" etc are not applicable
here.
This would be applicable if we called some_method() outside! But not
inside. Inside the function, it can freely treat params as non-null, as
long they are declared as non-nullable.
The best we can capture it is via StrictNonnull nullability.
Reviewed By: artempyanykh
Differential Revision: D20536586
fbshipit-source-id: 5c2ba7f0d
Summary:
`make test` failed in some test directories, because we were getting warnings
```
Foo.java uses unchecked or unsafe operations.
```
This diff fixes or suppresses these warnings.
Reviewed By: skcho
Differential Revision: D20557572
fbshipit-source-id: 63ecd3dfa
Summary:
First version of a new memory leak check based on Pulse. The idea is to examine unreachable cells in the heap and check that the "Allocated" attribute is available but the "Invalid CFree" isn't. This is done when we remove variables from the state.
Currently it only works for malloc, we can extend it to other allocation functions later.
Reviewed By: jvillard
Differential Revision: D20444097
fbshipit-source-id: 33b6b25a2
Summary:
- Add more naive pulse models for:
- `System.arraycopy`
- `StringBuilder.setLength`
- `StringBuilder.delete`
- Model the following as pure
- `SparseArrayCompat.valueAt`
- `File.get...`
- Add a nice test
Reviewed By: jvillard
Differential Revision: D20513397
fbshipit-source-id: 6d412d13a
Summary:
This diff continues work in D20491716.
This time for Inheritance Rule.
Reviewed By: jvillard
Differential Revision: D20492889
fbshipit-source-id: c4dfd95c3
Summary:
This diff continues work in D20491716.
This time for Dereference Rule.
Reviewed By: jvillard
Differential Revision: D20492296
fbshipit-source-id: ff7f824f9
Summary:
# Problem
In current design, Rules (assignment rule, dereference rule, inheritance
rule) decide, depending on the mode, wether the issue is legit or not.
If the issue is not actionable for the given mode, it won't be created
and registered.
For meta-issues, we want to be able to do smart things like:
- Identify if we can raise strictness of the mode without
introducing new issues
- Classify classes on "clean" vs "broken", taking into account issues
that are currently invisible.
# Solution
In the new design:
1. Rules are issuing violations independently of mode. This makes sense
semantically. Mode is "level of trust we have for suspicious things",
but the thing does not cease to be suspicious in any mode.
2. Each Rule decides if it is reportable or not in a given mode.
3. `nullsafe_mode` is passed to the function `register_error`, that 1)
adds error so it can be recorded in summary for file-level analysis
phase 2) reports some of them to the user.
# This diff
This diff converts only AssignmentRule, follow up will include
conversion of other rules, so no issue encapsutes the mode.
Reviewed By: jvillard
Differential Revision: D20491716
fbshipit-source-id: af17dd66d
Summary:
Previously, at each function call, we added a `WrittenTo` attribute for applying the address of the actuals. However, this results in mistakenly considering each function application that inspects its argument as impure. Instead, we should only propagate `WrittenTo` if the actuals have already `WrittenTo` attributes.
For instance, for the following functions
```
public static boolean is_null(Byte a) {
return a == null;
}
public static boolean call_is_null(Byte a) {
return is_null(a);
}
```
We used to get the following pulse summary for `call_is_null` (showing only one of the disjuncts):
```
#0: PRE:
{ roots={ &a=v1 };
mem ={ v1 -> { * -> v2 } };
attrs={ v1 -> { MustBeValid },
v2 -> { Arith =null, BoItv ([max(0, v2), min(0, v2)]) } };}
POST:
{ roots={ &a=v1, &return=v8 };
mem ={ v1 -> { * -> v2 }, v8 -> { * -> v4 } };
attrs={ v2 -> { Arith =null,
BoItv ([max(0, v2), min(0, v2)]),
WrittenTo-----------WRONG },
v4 -> { Arith =1,
BoItv (1),
Invalid ConstantDereference(is the constant 1),
WrittenTo-----------WRONG },
v8 -> { WrittenTo } };}
SKIPPED_CALLS: { }
```
where we mistakenly recorded a `WrittenTo` for `v2` (what `a` points to). As a result, we considered `call_is_null` as impure :( This diff fixes that since the callee `is_null` doesn't have any `WrittenTo` attributes for its parameter `a`. So, we don't propagate `WrittenTo` and get the following summary
```
#0: PRE:
{ roots={ &a=v1 };
mem ={ v1 -> { * -> v2 } };
attrs={ v1 -> { MustBeValid },
v2 -> { Arith =null, BoItv ([max(0, v2), min(0, v2)]) } };}
POST:
{ roots={ &a=v1, &return=v8 };
mem ={ v1 -> { * -> v2 }, v8 -> { * -> v4 } };
attrs={ v2 -> { Arith =null, BoItv ([max(0, v2), min(0, v2)]) },
v4 -> { Arith =1,
BoItv (1),
Invalid ConstantDereference(is the constant 1) },
v8 -> { WrittenTo } };}
SKIPPED_CALLS: { }
```
Reviewed By: skcho
Differential Revision: D20490102
fbshipit-source-id: 253d8ef64
Summary: These tests fail when seemingly unrelated changes are made to infer. In particular, it seems timeout limits have to be increased by 10x or more to make them succeed again. Disabling until we have a more stable replacement.
Reviewed By: ezgicicek
Differential Revision: D20489647
fbshipit-source-id: 9706b0807
Summary:
This diff naively models the following as `StdVector.push_back`:
- `StringBuilder.append`
- `String.replace`
- `Queue.poll`
It also adds a FN test for `Iterator.next`.
Reviewed By: skcho
Differential Revision: D20469786
fbshipit-source-id: 2d8e8d117
Summary:
This diff is doing three things:
1. Finishes work paved in D20115024, and applies it to nullsafe. In that diff, we hardened API for
file level analysis. Here we use this API in nullsafe, so now we can
analyze things on file-level, not only in proc-level like it was before!
2. Introduces a class-level analysis. For Nullsafe purposes, file is not
an interesting granularity, but we want to analyze a lot of things on
file level. Interesting part here is anonymous classes and how we link
them to their corresponding user-defined classes.
3. Introduces a first (yet to be improved) implementation of class-level
analysis. Namely it is "meta-issues" that tell what is going with class
on high level. For now these are two primitive issues, and we will
refine them in follow up diffs. They are disabled by default.
Follow ups include:
1. Refining semantics of meta-issues.
2. Adding other issues that we could not analyze before or analyzed not
user friendly. Most importantly, we will use it to improve reporting for
FIELD NOT INITIALIZED, which is not very user friendly exactly because
of lack of class-level aggregation.
Reviewed By: artempyanykh
Differential Revision: D20417841
fbshipit-source-id: 59ba7d2e3
Summary: The `FN_loop2` was not actually FN because infer analyzes its complexity as degree 1 correctly.
Reviewed By: dulmarod
Differential Revision: D20468367
fbshipit-source-id: 9e4c19415
Summary: The `iterate_over_mycollection_quad_FN` was not actually FN because infer analyzes its complexity as degree 2 correctly. So, this diff removed `_FN` from there.
Reviewed By: ezgicicek
Differential Revision: D20467398
fbshipit-source-id: b10340612
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: `Object.clone` modeled as pure until the analysis can distinguish returning a fresh object vs. having no side-effects.
Reviewed By: skcho
Differential Revision: D20439998
fbshipit-source-id: 421054cfb
Summary:
`JavaSplitName` is used to represent Java types (in `Procname` in particular). The type itself is a pair of string (an optional package qualifier) and a "type name" (the quotes are there because it may contain array qualifiers).
For example `java.lang.Object[][]` should be represented as
```
{package=Some "java.lang"; typename="Object[][]"}
```
The constructor `make` was misused to construct instead types such as
```
{package=None; typename="java.lang.Object[][]"}`
```
This is evident when we print the return type of a `Procname` non-verbosely (the default), but we still see the package qualifier.
Obviously this is not just a pretty-printing bug, the values were themselves wrong.
The fix is to use the `of_string` constructor which will parse the package and separate it correctly. Another bug (in response to this one) had to be fixed in `Procname.is_vararg` to maintain behaviour in Nullsafe and Quandary.
Reviewed By: mityal
Differential Revision: D20394146
fbshipit-source-id: 4633902eb
Summary:
Impurity domain was tracking all changes to variables (with a list of traces that containing all write/invalid accesses). This results in having long traces with multiple access events for the same variable. For instance,
```
void swap_impure(int[] array, int i, int j) {
int tmp = array[i];
array[i] = array[j]; \\ included in the trace
array[j] = tmp; \\ included in the trace
}
```
here we recorded both array accesses.
This diff changes the domain to include accesses so that we only keep track of a single trace per access. Array accesses are only recorded once.
Note that we want to record all unique accesses, not just the first one, because impurity will be used for hoisting/cost where we will invalidate impure arguments and consider all the rest as not changing.
Reviewed By: jvillard
Differential Revision: D20385745
fbshipit-source-id: d3647dad3
Summary:
D20362149 missed
- to pass the optional argument `include_value_history` to the recursive call in `PulseTrace.add_to_errlog`.
- to set `include_value_history=false` for skipped calls.
This diff fixes these issues.
Reviewed By: skcho
Differential Revision: D20385604
fbshipit-source-id: 176e4d010
Summary:
This was never quite finished and inferbo has a new way to do sort of
the same thing.
Reviewed By: skcho, ngorogiannis
Differential Revision: D20362619
fbshipit-source-id: 7c7935d47
Summary:
Make <infer-out>/report.json the default value for this option, as this
is what is used 99% of the time. Clean up test options using this.
Reviewed By: ngorogiannis
Differential Revision: D20362644
fbshipit-source-id: a1bb18757
Summary:
Adding a model for malloc: we add an attribute "Allocated". This can be used for implementing memory leaks: whenever the variables get out of scope, we can check that if the variable has an attribute Allocated, it also has an attribute Invalid CFree.
Possibly we will need more details in the Allocated attribute, to know if it's malloc, or other allocation function, but we can add that later when we know how it should look like.
Reviewed By: jvillard
Differential Revision: D20364541
fbshipit-source-id: 5e667a8c3
Summary: Impurity traces are quite big due to recording values histories. Let's simplify the traces by removing pulse's value histories.
Reviewed By: skcho
Differential Revision: D20362149
fbshipit-source-id: 8a2a6115e
Summary: Type is not enough to say a function call of `Provider.get` is expensive or not.
Reviewed By: jvillard
Differential Revision: D20366206
fbshipit-source-id: 83d3e8741
Summary:
This diff uses a type parameter of `Provider.get` to decide whether assigning expensive cost to the
function call or not. For example, if the type is small one like `Provider<Integer>`, it be
evaluated to have a unit cost, otherwise a linear cost.
To get the return type of `Provider.get`, I added a simple analyzer that collects "casted" types
backwards. In Sil, while the function call statement loses the return type, e.g,
```
n$5=_fun_Object Provider.get()(n$3:javax.inject.Provider*);
```
the `n$5`'s value is usually casted to a specific type at some point later.
```
*&$irvar0:java.lang.Object*=n$5
n$8=*&$irvar0:java.lang.Object*
n$9=_fun___cast(n$8:java.lang.Object*,sizeof(t=java.lang.Integer;sub_t=( sub )(cast)):void)
```
So, the analyzer starts from the cast statements backward, collecting the types to cast for each
variables.
Reviewed By: ezgicicek
Differential Revision: D20345268
fbshipit-source-id: 704b42ec1
Summary: This diff adds a model for Java's `Object.clone()` method (similar to existing shallow_copy).
Reviewed By: jvillard
Differential Revision: D20341073
fbshipit-source-id: 30ae40fe7
Summary:
Some (all?) of this is already tested in other tests, but this feature
is important enough (and the implementation is scattered accross the
whole code), so I found it useful to have a small test that ensures the
very basic things are working as expected.
See `NestedFieldAccess.java` that tests far more advances things, but
here we focus only very basic things: conditions, local variable
assignments, and explicit assignments.
Reviewed By: jvillard
Differential Revision: D20339056
fbshipit-source-id: a6cfd0043
Summary: We forgot to take skipped calls into account for state comparison. This diff fixes that.
Reviewed By: skcho
Differential Revision: D20282739
fbshipit-source-id: 7b4d84bb0
Summary:
These were not used (and were actually activated byt the same config
param). They both are in experimental stage that never reached maturity.
Since the team does not have immediate plans to work on ObjC nullability
checker; and since "eradicate" (now known as nullsafe) is the main
solution for Java, removing it is sensible.
Reviewed By: jvillard
Differential Revision: D20279866
fbshipit-source-id: 79e64992b
Summary:
This is the kind of property for which the previous syntax forced one to
use spurious registers.
Reviewed By: ngorogiannis
Differential Revision: D20118863
fbshipit-source-id: b49740d33
Summary: When reporting CapturedStrongSelf we shouldn't report it when the block is "no escaping", as this won't lead to a retain cycle, so capturing strongSelf is ok.
Reviewed By: jvillard
Differential Revision: D20224359
fbshipit-source-id: c60dae333
Summary:
Update handling of `OffsetOfExpr` based on the new type definition
from updated version of clang-plugin.
Together with the change to clang-plugin, this essentially fixes hard
crash while analysing C/C++ files with non-literal `offsetof`
expression.
Fixes GH issues [#1178](https://github.com/facebook/infer/issues/1178), [#1212](https://github.com/facebook/infer/issues/1212)
Reviewed By: jvillard
Differential Revision: D20159173
fbshipit-source-id: 65fc228a4
Summary:
This diff renames `ZERO_XXX` issues to more appropriately named and descriptive
`XXX_UNREACHABLE_AT_EXIT` and replaces bottom with
unreachable in cost kinds and issues.
Reviewed By: skcho
Differential Revision: D20140301
fbshipit-source-id: eb6076b30
Summary:
1. It is convenient to stick with the policy "ERROR if and only if it is
enforced". Among other, it makes CI integration much easier to implement
(enforcemend, UI and messaging is decided based on severity).
2. Since Nullsafe annotation is an idiomatic way to indicate classes
with enforced nullability checking, we want it to be the only way to
enforce issues.
3. This means we decrease the priority of GraphQL violation issues.
(In practice they were not enforced so we have plenty of violations in
codebase to reflect reality). The proper way dealing with GraphQL will
be detecting such issues as a special issue type and prioritizing fixing
and Nullsafe-ifying corresponding classes.
4. Among other, we downgrade severity of field overannotated to advice
to keep it consistent with condition redundant.
Reviewed By: artempyanykh
Differential Revision: D20141420
fbshipit-source-id: e2f12835a
Summary:
The issue type `ZERO_EXECUTION_TIME` actually corresponds to bottom state but has been mistakenly used to mean
- unreachable nodes (program never reaching exit state)
- having zero cost (e.g. for allocations).
Note that, for execution costs, the latter doesn't make sense since we always incur a unit cost for the start node. Hence, a function with empty body will have unit cost. For allocations or IO however, we only incur costs for specific primitives, so a function with no allocations/IO could have a zero cost. However, there is no point reporting functions with zero cost as a specific issue type. Instead, what we want to track is the former, i.e. functions whose cost becomes 0 due to program never reaching exit state.
This diff aims to split these cases into two by only reporting on the latter and adds traces to bottom/unreachable cost by creating a special category in polynomials.
Next diff will rename `ZERO_XXX` to `XXX_UNREACHABLE_AT_EXIT`.
Reviewed By: skcho
Differential Revision: D20005774
fbshipit-source-id: 46b9abd5a
Summary:
For Mode.Local this is kind of obvious decision.
But this diff does the same for strict mode as well.
See comment in [ExplicitNonnullThirdParty] for the detailed explanation.
Reviewed By: artempyanykh
Differential Revision: D20140056
fbshipit-source-id: 13c66df81
Summary:
In the previos diff we restructured error rendering utils for
TypeOrigin.MethodCall.
In this diff we do the same with TypeOrigin field: lets make the code
consistent.
We also clearly distinct third party from all other possible cases in
this branch.
This changes messaging and reported errors for strict modes (see test cases), and I believe this is a net improvement.
Reviewed By: artempyanykh
Differential Revision: D20139741
fbshipit-source-id: 84f502553
Summary:
> We don't report when the cost is Top as it corresponds to subsequent 'don't know's. Instead, we
> report Top cost only at the top level per function
The previous code just ignored top costed nodes, so it was able to report a non-top cost that was
from another node. For example,
```
void foo() {
linear-cost();
top-cost();
}
```
It reported inconsistent reports: `EXPENSIVE_EXECUTION_TIME` with a linear cost and
`INFINITE_EXECUTION_TIME` at the same time.
This diff fixes it not to report `EXPENSIVE_EXECUTION_TIME` when there is a node with the top cost.
Reviewed By: ezgicicek
Differential Revision: D20139408
fbshipit-source-id: 9fedd4aec
Summary:
In the previous report, it reported the first cost of node that exceeds a threshold. However, this
may hide a bigger cost of node that appears later. This diff changes this to report the biggest
cost of node among the costs exceeding the threshold.
Reviewed By: ezgicicek
Differential Revision: D20116162
fbshipit-source-id: 06199fb46
Summary:
Current domain of Inferbo cannot handle float values. This diff evaluates float constants to the top
interval.
Reviewed By: ezgicicek
Differential Revision: D20116361
fbshipit-source-id: e6e398bbd
Summary:
This syntax
- is less confusing (according to several people who are not me);
objectively, there's less magic under the hood
- gives fine control over register number (because condition/action are separated)
- lets one compare values of different arguments of the same call
(e.g., one could have a transition that is taken only if two
arguments of a method call are equal)
Reviewed By: ngorogiannis
Differential Revision: D20005403
fbshipit-source-id: fad8f3b3d
Summary:
The test shows what that TOPL can express, in addition to bugs,
efficiency properties. However, there seems to be an underlying problem
in biabdaction that prevents this particular problem from being caught.
Reviewed By: ngorogiannis
Differential Revision: D20005404
fbshipit-source-id: 466f79050
Summary: The semantics of the `values` function of Java enum class was missing, when it is called outside the class initializer. This diff gets the size of the enum elements from the summary of class initializer function, `<clinit>`.
Reviewed By: ezgicicek
Differential Revision: D20094880
fbshipit-source-id: 7362bba1c
Summary: We had no tests that resulted in `ZERO_EXECUTION_COST`. Let's fix that.
Reviewed By: skcho
Differential Revision: D20097504
fbshipit-source-id: 56c23fea0
Summary:
Now when typechecking a class `A` marked with `Nullsafe(LOCAL)`,
classes from trusted list are properly recognized and nullability of
method params and return value are refined to `LocallyCheckedNonnull`
in a context of class `A`.
NOTE: refininng nullability when **accessing fields** on trusted classes
is **not implemented yet**, because the whole business of handling fields
in nullsafe is somewhat convoluted. This should not be a huge issue
though, since in Java fields are commonly accessed via getters any
way.
Reviewed By: mityal
Differential Revision: D20056158
fbshipit-source-id: 496433d90
Summary:
This will help making error reporting more actionable.
Often methods that are nullable in general (like View.findViewById) are used as not-nullable due to app-invariants. In such cases suggesting a non-nullable alternative that does an assertion under the hood makes the error report more actionable and provides necessary guidance with respect to coding best practices
Follow up will include adding more methods to models.
If this goes well, we might support it in user-defined area (nullability
repository)
Reviewed By: artempyanykh
Differential Revision: D20001416
fbshipit-source-id: 46f03467c
Summary:
Introduction of `ThirdPartyNonnull` nullability broke nullability
refinement heuristic for enums. This diff fixes it and also adds tests
so that we hopefully avoid such issues in future.
Reviewed By: mityal
Differential Revision: D19975810
fbshipit-source-id: f9245f305
Summary:
We need to be able to differentiate `UncheckedNonnull`s in internal vs
third-party code. Previously, those were under one `UncheckedNonnull`
nullability which led to hacks for optmistic third-party parameter
checks in `eradicateChecks.ml` and lack of third-party enforcement in
`Nullsafe(LOCAL, trust=all)` mode (i.e. we want to trust internal
unchecked code, but don't want to trust unvetted third-party).
Now such values are properly modelled and can be accounted for
regularly within rules.
Also, various whitelists are refactored using
`Nullability.is_considered_nonnull ~nullsafe_mode nullability`.
`ErrorRenderingUtils` became a tad more convoluted, but oh well, one
step at a time.
Reviewed By: mityal
Differential Revision: D19977086
fbshipit-source-id: 8337a47b9
Summary:
Add support for nullsafe mode with `trust=all` and `trust=none` a case
with a specific trust list is not supported yet and needs to be
implemented separately.
Tests introduce one unexpected
`ERADICATE_INCONSISTENT_SUBCLASS_PARAMETER_ANNOTATION` issue which
complains about `this` having incorrect nullability; it is a bug and
needs to be fixed separately.
Reviewed By: mityal
Differential Revision: D19662708
fbshipit-source-id: 3bc1e3952
Summary: In all other cases we have period at the end, which is inconsistent.
Reviewed By: artempyanykh
Differential Revision: D20001065
fbshipit-source-id: 85ec6d751
Summary:
Use a record of package, class name to store (qualified) Java class names. This saves the round trip of concatenating then splitting again, etc, as well as saves some memory in the type environment as now the package paths can be shared across classes of the same package (about 10% in tests).
Also remove some unfortunate APIs.
Reviewed By: jvillard
Differential Revision: D19969325
fbshipit-source-id: f7b7f5a55
Summary: The way `Mangled.t` is used in `JavaClassName` means that it's always a plain string (we never have a "mangled" part). Remove the indirection and extra allocation. Also, simplify the API by throwing away one function that was used just once and wastefully.
Reviewed By: artempyanykh
Differential Revision: D19950672
fbshipit-source-id: b61fcba6e
Summary: This diff suppresses integer overflow issues in functions that includes "hash" in its name.
Reviewed By: jvillard
Differential Revision: D19942654
fbshipit-source-id: d86fa4f00
Summary: Once we identify a weakSelf variable that is being used in a Noescape block, we want to report only the first occurrence.
Reviewed By: skcho
Differential Revision: D19941502
fbshipit-source-id: 2b6d4648b
Summary: For each variable that we identify as a captured strong self, we want to report only the first occurrence.
Reviewed By: skcho
Differential Revision: D19940031
fbshipit-source-id: f38f642c9
Summary: When we discovered that a strongSelf var was not checked for null, we then report in each occurrence which is spammy. Now we report only the first occurrence. To achieve that, we store a `reported` flag in the domain that gets set to true after we report once, and we only report if it's false.
Reviewed By: jvillard
Differential Revision: D19877218
fbshipit-source-id: c44109ae9
Summary:
This adds a violation of baos.topl found in github/seata/seata. However,
it is not a bug (see comment in commit).
Reviewed By: ngorogiannis
Differential Revision: D19518641
fbshipit-source-id: e219245ee
Summary:
Since Javalib 3.2, a new feature allows to rewrite
methods that contain (some specific form of) closures. Infer
now uses it. When loading each class we rewrite them and
new classes generated by Javalib to implements closures
(i.e. Java interfaces)<
Reviewed By: ngorogiannis
Differential Revision: D19389227
fbshipit-source-id: 245dd4404
Summary:
When finding a proper constructor for `std::make_shared`, the given parameter types are sometimes
slightly different, e.g., const int vs int. This diff loosens the condition of the types on finding
constructors.
Reviewed By: ngorogiannis
Differential Revision: D19743198
fbshipit-source-id: f90213109
Summary:
This diff fixes the clang translation for switch statement. It assumed that `default:` comes always
at last, which introduced some unreachable nodes inadvertently, e.g. when `default:` comes at first.
Reviewed By: dulmarod
Differential Revision: D19793138
fbshipit-source-id: 1e8b52c0d
Summary:
We already warn about lack of nullable annotations in `equals()`, and even have a specialized error message for that.
But lack of an annotation is not as severe as direct dereference: the
latter is a plain bug which is also a time bomb: it will lead to an NPE not immediately.
This is widespread enough to be reported separately.
Reviewed By: dulmarod
Differential Revision: D19719598
fbshipit-source-id: a535d43ea
Summary:
Since we fixed a bug in implementation of FalseOnNull (see stack below),
we can finally ship this change.
Side note: this change is essential for the follow up diff (which adds extra check
for user-defined implementations of equal()), without it the follow
up change would introduce a lot of false positives.
Reviewed By: ngorogiannis
Differential Revision: D19771057
fbshipit-source-id: 7d7cf1ef7
Summary:
If we managed to whitelist a function as TrueOnNull, we should teach
nullsafe the nullability of its arguments, otherwise it will ask not to
pass null here.
This fixes a silly FP warning, see the test.
Reviewed By: dulmarod
Differential Revision: D19770341
fbshipit-source-id: 0f861fae1
Summary:
Yay, the previous refactoring finally makes it possible to do some actual
changes to the code in `TypeCheck.ml`!
Changes in this diff:
1. Fixes the bug: TrueOnNull and FalseOnNull were working only for
static methods. Surpsingly nobody noticed that. It is because the first
argument for non-static method was `this`.
2. Behavior change: TrueOnNull/FalseOnNull were not working correctly
where there are several argumens. See the task attached for the example
of the legit usecase. Now the behavior is the following: if there are
several Nullable arguments infer nullability for all of them.
Reviewed By: skcho
Differential Revision: D19770219
fbshipit-source-id: 7dffe42cd
Summary:
This refactoring unblocks the changes in follow up diffs (plus fixes a
bug).
So what was happening?
Each comparison with null leads to CFG being splitted into two branches, one branch
is PRUNE(a == null) and another is PRUNE(a != null).
PRUNE(a != null) is where most of logic happens, it is the place where
we infer non-null nullability for a, and this is a natural place to
leave a check for redundancy.
Before this diff we effectively checked the same thing twice, and used
`true_branch` (only one of 2 instruction will have it set to true) as a symmetry breaker.
This diff removes the `true_branch` checks, but leaves only one call out
of two, hence breaking symmetry in a different way.
## Bug fix
The code around the removed check was (crazily) doing two things at
once: it processed results of (returning booleans!)
TrueOnNull-annotated functions AND
results of (returning Objects!) other functions, using the fact that all
of them are encoded as zero literals (sic!).
Not surprisingly that lead to a bug where we accidentally call the check
for non intended places (arguments of trueOnNull functions), which lead
to really weird FP.
This diff fixes it.
Reviewed By: dulmarod
Differential Revision: D19744604
fbshipit-source-id: fe4e65a8f
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: We don't use allocation costs in prod at the moment. There is no plan to do so in the near future. Let's not report them anymore and also save some space in `costs-report.json`.
Reviewed By: skcho
Differential Revision: D19766828
fbshipit-source-id: 06dffa61d
Summary:
This diff adds a taint domain in Inferbo. The taint value will be used to find vulnerable array
accesses in the following diffs.
Reviewed By: ezgicicek
Differential Revision: D19391028
fbshipit-source-id: 566b4c0fe
Summary:
This test tests PropagatesNullable and TrueOnNull/FalseOnNull
annotations.
Both tests suites grew big so it is hard to observe them at glance and
make changes.
I could not figure out better name for TrueFalseOnNull.java, it is sort
of silly but I optimized for searchability, "FalseOnNull" will be
directly searched and "TrueOnNull" will be searched in IDEs that are
smart enough.
Reviewed By: skcho
Differential Revision: D19724512
fbshipit-source-id: 703961342
Summary: This diff returns non-symbolic value (top) for unknown external function calls because the symbolic values sometimes make it hard to understand costs.
Reviewed By: ezgicicek
Differential Revision: D18685715
fbshipit-source-id: 1b39c718b
Summary:
Pulse has an extra invalidation mechanism (introduced in D18726203) to prevent something invalid (e.g. `null`) to be passed by reference to an initialisation function. Therefore, it havocs formals passed by reference to skipped functions. However, I don't think this makes sense in Java. So, let's turn it off.
A nice consequence of this is that in impurity analysis, we do not consider functions that call skipped library calls with object arguments as writing to their formals.
Reviewed By: skcho
Differential Revision: D19697110
fbshipit-source-id: 6e3a71f2a
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:
Revert incomplete/incorrect translation of `synchronized` in ObjC.
The current translation is incomplete because
```
syncrhonized(foo){
return;
}
```
should be translated as
```
__set_locked_attribute(foo);
__delete_locked_attribute(foo);
return;
__delete_locked_attribute(foo);
```
but instead we get
```
__set_locked_attribute(foo);
return;
__delete_locked_attribute(foo);
```
The same applies for `break`/`continue` etc
Reviewed By: skcho
Differential Revision: D19718882
fbshipit-source-id: fc49ef529
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:
`String` and `StringBuilder` both implement `CharSequence`. Let's generalize the model for `String` to `CharSequence` wherever possible and add missing models for
- `StringBuilder.append`
- `StringBuilder.toString`
Reviewed By: skcho
Differential Revision: D19558009
fbshipit-source-id: 0dfdb21af
Summary:
Java's String models were broken for
- initializing a String object with a locally defined constant string (which is an `Object*` in SIL).
- initializing a String object with a `char`/`byte` array
This diff fixes them and also adds models for `new String ()`.
Reviewed By: skcho
Differential Revision: D19662180
fbshipit-source-id: 23968d0aa
Summary: This diff fixes the array access checking function for nested global arrays. We had assumed that RHS of `store` statement in SIL does not include array access expression, but that is not true: for global arrays, SIL can have statements like `*LHS = GlobalArray[n][m]`.
Reviewed By: ezgicicek
Differential Revision: D19300153
fbshipit-source-id: 256325642
Summary:
This diff gives semantics of `std::make_shared` as simple constructor, i.e., it changes function
call of `std::make_chared<C>(i)` to the constructor `C(i)`.
Reviewed By: ngorogiannis
Differential Revision: D19432338
fbshipit-source-id: 0d838e555
Summary: This adds a check for when developers use weakSelf (and maybe strongSelf) in a block, when there is no need for it, because it won't cause a retain cycle. In general there is an annotation in Objective-C for methods that take blocks, NS_NOESCAPE, that means that the passed block won't leave the scope, i.e. is "no escaping". So we report when weakSelf is used and the block has the annotation.
Reviewed By: ngorogiannis
Differential Revision: D19662468
fbshipit-source-id: f5ac695aa
Summary:
Prevent returning a negative cost bound when calling `substring(begin_index, end_index)` when either is possible
- `begin_index < 0`
- `begin_index > end_index`
Instead, return unit cost since such cases either throw `IndexOutOfBoundsException ` at runtime or correspond to having two symbolic bounds that cannot be semantically compared.
Reviewed By: dulmarod
Differential Revision: D19619410
fbshipit-source-id: cf5e8cb7b
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: The translation of closures includes a load instruction for the captured variable, then we add that corresponding id to the closure. This doesn't correspond to an actual "use" of the captured variable in the source program though, and causes false positives. Here we remove the ids from the domain when that id is being added to a closure.
Reviewed By: ngorogiannis
Differential Revision: D19557352
fbshipit-source-id: 52b426011
Summary:
- Add `Nullsafe` annotation as a general mechanism to specify
type-checking behaviour for nullsafe.
- Document annotation params and provide usage examples with
explanations.
- Add tests to demonstrate the behaviour with different type-checking
modes.
No implementation is added. This diff serves as an RFC to hash out the
details before I dive into code.
Reviewed By: ngorogiannis
Differential Revision: D19578329
fbshipit-source-id: b1a9f6162
Summary: `String.split(regexp)` returns an array that is split by the given regexp. If the regexp doesn't match, the original string is returned. Hence, the resulting array's length must be in `[1, max(1, n_u -1)]` where`n_u` is the upper bound of the string's length.
Reviewed By: dulmarod
Differential Revision: D19578318
fbshipit-source-id: 675af7376
Summary:
Adding a new check as part of the SelfInBlock checker, for cases when a strong pointer to self, that is not self, is captured in the block.
This will cover the following wrong scenarios:
1. strongSelf is a local variable in a block as it should be, and then it's used in a sub-block, in which case it's a captured variable.
2. weakSelf is defined without the weak attribute by mistake.
Reviewed By: ngorogiannis
Differential Revision: D19538036
fbshipit-source-id: 151871745
Summary:
In practice, condition redundant is extremely noisy and low-signal
warning (hence it is turned off by default).
This diff does minor tweaks, without the intention to change anything
substantially:
1/ Change severity to advice
2/ Change "is" to "might be"
3/ Describe the reason in case the origin comes from a method.
The short term motivation is to use 3/ for specific use-case: running nullsafe on codebase and
identify most suspicious functions (that are not annotated by often
compared with null).
Reviewed By: artempyanykh
Differential Revision: D19553571
fbshipit-source-id: 2b43ea0af
Summary: We were reporting strongSelf Not Checked when the variable was checked in a conditional, this diff fixes that.
Reviewed By: jvillard
Differential Revision: D19535943
fbshipit-source-id: f8e64e1b7
Summary: I noticed when looking into a false positive of strongSelf Not Checked, that there were some inconsistencies in the translation of if statements with an and, with an extra redundant join only if using a method in the condition that returned an object. So I could repro the problem and investigate and found the place of the inconsistency in the translation. This diff fixes it without changing things too much.
Reviewed By: jvillard
Differential Revision: D19518368
fbshipit-source-id: 47a6a778c
Summary:
The order by which the scheduler visits odd and even methods here
will determine if there is any report at all. This is a bad test
so remove.
Reviewed By: fgasperij
Differential Revision: D19535537
fbshipit-source-id: 6b64b0de9
Summary: Adding reporting to strongSelf Not Checked when strongSelf is passed to a method in a not explicitly nullable position.
Reviewed By: ezgicicek
Differential Revision: D19330872
fbshipit-source-id: 95871a70a
Summary: After receiving feedback about this, I'm changing the reporting of strongSelf Not Checked to only in cases where it can cause a crash. Here I'm adding reporting for field access, and removing general reporting. In a next diff, I'll also add reporting for passing strongSelf to methods in not explicitly nullable positions.
Reviewed By: skcho
Differential Revision: D19329842
fbshipit-source-id: 35beb2aa3
Summary:
1. One should use either a writer or a stream to send a response, but not both.
2. A response should be forwarded only if it was commited.
Both properties are extracted from API comments on classes in the servlet API.
Reviewed By: jvillard
Differential Revision: D19514568
fbshipit-source-id: 79f0257ed
Summary:
If data comes from an outer OutputStream, then this outer OutputStream
needs to be flushed before getting the byte array.
Reviewed By: jvillard
Differential Revision: D19514569
fbshipit-source-id: e3e025394
Summary: We were lacking this kind of test where one interface refines the nullability of the other.
Reviewed By: ngorogiannis
Differential Revision: D19514245
fbshipit-source-id: fa3e781f3
Summary:
This is a common enough case to make error message specific.
Also let's ensure it's modelled.
Reviewed By: artempyanykh
Differential Revision: D19431899
fbshipit-source-id: f34459cb3
Summary:
The previous diff changes the message for params case, this one handles
return.
Reviewed By: artempyanykh
Differential Revision: D19430706
fbshipit-source-id: f897f0e56
Summary:
This diff gets global constant array values from their initializers. The `find_global_array` function is
added to memory domain, which finds values of global array locations during the ondemand value
generation.
Reviewed By: ngorogiannis
Differential Revision: D19300143
fbshipit-source-id: 7b0b84c42
Summary: Use more informative method names, and add comments explaining the logic behind each test. Correct two cases which are FPs instead of legitimate reports.
Reviewed By: artempyanykh
Differential Revision: D19465227
fbshipit-source-id: 29332e2b9
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:
Currently, impurity analysis is oblivious to skipped functions which might e.g. return a non-deterministic value, write to memory or have some other side-effect. This diff fixes that by relying on Pulse's skipped functions to determine impurity. Any unknown function which is not modeled to be pure is assumed to be impure.
This is a heuristic. We could have assumed them to be pure by default as well.
Reviewed By: jvillard
Differential Revision: D19428514
fbshipit-source-id: 82efe04f9
Summary:
As suggested by Ilya, the current message can be improved in a way that
it can contain more clear action. I also added artempyanykh's explanation at the
end of message to provide an additional justification from common sense
perspective.
But most importantly, the previous message was missing a space which is
eye bleeding, how come haven't I noticed this before, I can't stand it
OMG.
Reviewed By: artempyanykh
Differential Revision: D19430271
fbshipit-source-id: dd31f7adb
Summary:
Inferbo analyzed some program points unreachable incorrectly, because of unsound semantics of band
operator, which did not handle the case when given parameters are pointer values.
Reviewed By: ngorogiannis
Differential Revision: D19392705
fbshipit-source-id: dd590508c
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:
This diff avoids that `array_sizeof` returns bottom value when given Java enum values, which
introduced unreachable code inadvertently.
Reviewed By: ngorogiannis
Differential Revision: D19409077
fbshipit-source-id: 2816fd995
Summary:
The property SkipAfterRemove already had a test, but not for
intra-procedural violations. This adds a test for that case.
Reviewed By: ngorogiannis
Differential Revision: D19330471
fbshipit-source-id: 1dd1c3ad7
Summary: This diff implements this for Field Not Initialized check
Reviewed By: artempyanykh
Differential Revision: D19393989
fbshipit-source-id: cf60e8d53
Summary: add subdirectories so that we can run each java file against its own topl properties
Reviewed By: rgrig
Differential Revision: D19347302
fbshipit-source-id: 562830774
Summary:
This diff does it for nullable dereference and assignment violations
rules which happen under NullsafeStrict case.
Follow up are to make the same for inheritance and field initializer
violations.
Possible follow up includes making error message more specific and
articulare this this is a nullsafe strict mode.
Reviewed By: artempyanykh
Differential Revision: D19392916
fbshipit-source-id: 2554ac7a7
Summary:
Previously, _override resolution_ considered only the number of
arguments. This led to many FPs in nullsafe's _Inconsistent Subclass
Annotation_ check.
Current version also checks that argument types match. However, we
still don't handle type parameters and erasure, so in this sense the
rules are incomplete.
Reviewed By: ngorogiannis, mityal
Differential Revision: D19393201
fbshipit-source-id: a0c75b8dd
Summary:
This diff avoids that null-retuned path's abstract value ruins that of non-null-returned path.
What this diff does is: when joining two abstract states, one is null-return-path and the other is
non-null-return-path (`return obj;`), it keeps the method calls of `obj` from the
non-null-return-path.
While this design is unsound, I think it should work in practice.
Reviewed By: ezgicicek
Differential Revision: D19348313
fbshipit-source-id: cf5d0f3ff
Summary: This diff captures global initializers ondemand, like we do for functions defined in headers.
Reviewed By: ezgicicek
Differential Revision: D19346947
fbshipit-source-id: 05174e6a4
Summary:
Java treats switch on nullables in a non-obvious way (throws an NPE
surprise) so lets have a decidated test exactly for this.
Reviewed By: ngorogiannis
Differential Revision: D19371280
fbshipit-source-id: d9867b6d6
Summary:
Demonstrate that the per-file type environments don't prevent
the deadlock report here. The fear was that when the analyser
tries to locate the methods of the endpoint class, it might fail to
do so because the types might be stored in different type
environments (per file).
Reviewed By: mityal
Differential Revision: D19225908
fbshipit-source-id: 097e4aeea
Summary: This diff use actuall call path in the cost results instead of `class name + method name`.
Reviewed By: ngorogiannis
Differential Revision: D19194969
fbshipit-source-id: b72018586
Summary:
Model array length in Java as returning an unknown interval [0, +inf] for now.
Ideally, we can deal with the size in a more precise manner in the future like in InferBo.
Reviewed By: skcho
Differential Revision: D19312123
fbshipit-source-id: 8c51059a4
Summary: Pulse doesn't care about exceptions yet. With Exceptional CFG, java analysis takes a lot of time due to having many disjuncts. Let's use Normal CFG for now.
Reviewed By: jvillard
Differential Revision: D19194479
fbshipit-source-id: f94bb6078
Summary:
In order to improve the impurity analysis, this diff adds models for
- `hasNext()` and - `Object.equals()` modeled as returning a non-deterministic value (havoc_id)
- `next()` modeled as `StdVector.get` with a fresh index
- `iterator` modeled as just returning the underlying list
Reviewed By: jvillard
Differential Revision: D19177392
fbshipit-source-id: 0babb037a
Summary:
This diff updates the relation between iterator (offset) and integer value not only at
assignments (`x += 1`), but also at function calls (`foo()`) that increase integer values by one in
their side effects.
Reviewed By: ezgicicek
Differential Revision: D19163214
fbshipit-source-id: 47e52f939
Summary: This diff extends the domain to express the relation between iterator's offset and integer value.
Reviewed By: ezgicicek
Differential Revision: D19143670
fbshipit-source-id: 6223bc934
Summary:
Old versions of sawja/javalib got the line numbers slightly wrong. The workaround was to do a regexp search in the source file for the right line.
My understanding is that this is no longer necessary. This diff removes it.
Reviewed By: jvillard
Differential Revision: D19033415
fbshipit-source-id: 2da19d66d
Summary:
This is an optimization. We ask the user to tell us which states are nondeterministic, and we
generate code that handle nondeterminism only for those states. It is common for only one state per
TOPL property to be nondeterministic. This speeds up the biabduction-analysis of the monitor by a
factor of ~10. But, using the monitor is only a little faster.
Facebook
Reviewed By: jvillard
Differential Revision: D19160286
fbshipit-source-id: 4dd39769a
Summary:
In the previous code, it removed non-build-called method calls. For example, it was like
```
{non-build-called: {prop1, prop3}}
{build-called: {}}
b.build();
{non-build-called: {}}
{build-called: {prop1, prop3}}
```
However, this behavior introduced a false positive when there is multiple builders that point to the
same abstract object and `build` is called one by one.
This diff changes the semantics to keep the method calls of non-build-called at `build` calls.
Reviewed By: ezgicicek
Differential Revision: D19144525
fbshipit-source-id: e2ace127f
Summary:
This applies some simplifications that were previously
done after footprint (and therefore lost), and some
simplifications that require looking at both pre and
post.
Reviewed By: ngorogiannis
Differential Revision: D19035494
fbshipit-source-id: bad79534a
Summary:
This havocs event data, so that biabduction doesn't try to
track what was the last event processed by the monitor
(which is redundant as long as the state of the monitor
is tracked).
Reviewed By: ngorogiannis
Differential Revision: D19035491
fbshipit-source-id: a1c75daae
Summary:
Don't instrument SIL when we can determine statically that
biabduction symexec would be a no-op.
Reviewed By: ngorogiannis
Differential Revision: D19116849
fbshipit-source-id: 4d25462a3
Summary: It is confusing to report missing props at the the beginning of the method (especially when there are many components created or when the method has many lines). Let's report them at create methods to better contextualize. Also, make the missing prop bold.
Reviewed By: skcho
Differential Revision: D19141135
fbshipit-source-id: a23d2e7c9
Summary:
In addition to
state1 -> state2: pattern
one can now also write
state1 -> state2: pattern if condition
where "condition" is some conjunction of comparisons (==,<,>) that
involve variables bound by "pattern", registers of the automaton, and
constants.
Reviewed By: ngorogiannis
Differential Revision: D19035496
fbshipit-source-id: 6f6e6a9be
Summary:
According to Java semantics, they are always non-null.
Internally they are represented as static fields, so they have
DeclaredNonnull nullability, which means NullsafeStrict mode would
refuse to use them without strictification.
Lets teach nullsafe that these guys are non-nullables.
See also FN in test case.
Reviewed By: ngorogiannis
Differential Revision: D19024547
fbshipit-source-id: 8c120fa50
Summary:
We do not have the create method in the trace which makes it difficult to understand
- inter-procedural issues where create and prop setting are in different methods
- there are multiple create-build chains in a method
Let's add the create to the beginning of the trace. Moreover, let's simplify the prop printing to make traces easier to understand.
Reviewed By: ngorogiannis
Differential Revision: D19020213
fbshipit-source-id: 7f8a5d4ec
Summary: The new domain is much better than the old one. Let's kill the old one (along with old litho tests) and simplify things.
Reviewed By: skcho
Differential Revision: D18959627
fbshipit-source-id: df77ae20e
Summary:
In order to handle the example added:
changed domain of `MethodCalled`
from `CreatedLocation -> (IsBuildCalled X IsChecked X Set(MethodCall))`
to `(CreatedLocation X IsBuildCalled) -> (IsChecked X Set(MethodCall))`
This avoids joining of two method calls where one is build-called and the other is not, e.g.,
```
if(b) {
o.build();
} else {
// no build call
}
```
changed domain of `NewDomain`
from `Created X MethodCalled`
to `(Created X MethodCalled) X (Created X MethodCalled)`
One is for no returned memory and the other is returned memory. This keeps precision some join
points of branches, e.g.,
```
if(b) {
return;
} else {
// no return
}
```
Reviewed By: ezgicicek
Differential Revision: D18909768
fbshipit-source-id: c39d1a1ef
Summary:
A plus is a plus, no need to give up when +/- is about pointers. This
gets rid of some false positives involving pointer arithmetic.
However, the problem remains if we make things a bit more
inter-procedural. This is documented in an added test.
Reviewed By: ezgicicek
Differential Revision: D18932877
fbshipit-source-id: 4ad1cfe72
Summary: It is not used anywhere and there are no plans to revive it. Kill it!
Reviewed By: skcho
Differential Revision: D18934719
fbshipit-source-id: b9b069b96
Summary:
The `Typ.FIeldname` module has many issues. Among those:
- It has 5 different string/printing functions and most of them do radically different things in Java and in Clang.
- There is no type safety: creating a Clang field and calling a Java function on it will lead to a crash (`rindex_exn` etc, there are usually no dots in Clang fields).
- It uses a single string for Java fields, containing the package, the class and the field, e.g., `java.lang.Object.field`. This is wasteful, because
- there is no sharing of strings for packages/classes, and,
- string operations need to be performed every time we need the field or the class or the package alone.
This diff preserves the behaviour of the module's interface, so the API problems remain.
However, by using a saner representation for Java fields we can get small performance and large memory gains (the type environment in Java is much smaller, about 30-40%).
In addition, many functions on clang fields would previously do string manipulations (look for `.` and split on it) before returning the final field unchanged -- now they use the type of the field for that.
Reviewed By: jvillard
Differential Revision: D18908864
fbshipit-source-id: a72d847cc
Summary:
- Do most of the work of `solve_arithmetic_constraints` inside `subst_attribute` instead, since we need to re-use the latter function for post-conditions where the first function is not appropriate.
- When substituting arithmetic constraints, we refine arithmetic information (both concrete intervals and inferbo), which can lead to inconsistent states. Instead of recording the new arithmetic facts by returning a new current state, just act as a map on attributes. This is to enable doing the point above.
- All this lead to a somewhat messy refactoring...
- Rename `CannotApplyPre` to `Contradiction` since it's used for post-conditions as well now
Reviewed By: skcho
Differential Revision: D18889120
fbshipit-source-id: d81647143
Summary: Guava uses assertions to ensure a future can be gotten without blocking (this means that if the future is not done, the app will crash). This diff teaches the starvation analyser about a number of such assertions, by treating them as assumes (since we don't care about exceptions).
Reviewed By: jvillard
Differential Revision: D18893427
fbshipit-source-id: 4d26a202b
Summary: A future is guaranteed not to block if `isDone()` has returned true first. Add logic for supporting that by remembering the objects that we have called `isDone` on and by making `assume` do the right thing with that knowledge. All this is achieved with the attribute domain.
Reviewed By: ezgicicek
Differential Revision: D18833901
fbshipit-source-id: 7f4ea0cd1
Summary:
When retrieving a value from a container, we previously had an arbitrary hack which would
- In java, give no ownership to the returned object (trying to be sound)
- In C++ give conditional ownership to the current method's first argument (trying to be complete, but doing it badly, as the first argument may not be the `this` object in a static method, or we might be accessing it through another parameter altogether).
Harmonise both by using the existing ownership of the container as ownership value for the returned object (leaning towards completeness).
Reviewed By: jvillard
Differential Revision: D18882800
fbshipit-source-id: f98f8d315
Summary:
Pointers are hard... The previous test had no chance of doing
initialisation of the pointer by reference and was in fact a false
negative (and still is, fix incoming). Renamed functions to stress the
false negative and added a test that is really (potentially) doing
pointer initialisation by reference.
Reviewed By: skcho
Differential Revision: D18888008
fbshipit-source-id: 1e72408c7
Summary:
This reverts commit 4fd6165d190bab32544f9f040b777565432c15b2.
We don't need to check for reporting each node anymore. It suffices to just check per function.
Reviewed By: skcho
Differential Revision: D18883833
fbshipit-source-id: 2591b3af3
Summary:
Making `MethodCalled` an inverted map from created location to method calls results in not being able to track a builder that is created in two different branches of a conditional with different types. Instead, we can make `MethodCalled` simply a map and also change `Created` to be a map from access paths to a set of created locations.
To deal with the case of setting a prop only in one branch, we need to ensure that whenever we call a create method, we add a binding to `MethodCalled` with an empty list of methods so that its intersection with a non-empty one is empty.
Reviewed By: skcho
Differential Revision: D18883097
fbshipit-source-id: b3464ca20
Summary: As long as the types match, it should be possible to call build on two components that are created at different locations.
Reviewed By: skcho
Differential Revision: D18881740
fbshipit-source-id: 356f9e168
Summary:
Finally use information from the inferbo intervals in pulse's domain to
make decisions about whether conditionals are feasible or not.
Reviewed By: skcho
Differential Revision: D18811193
fbshipit-source-id: d80a28657
Summary: Add a FN that is detected by the old domain but not the new one
Reviewed By: ngorogiannis
Differential Revision: D18854389
fbshipit-source-id: 9bdc90a6b
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 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:
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: 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: 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 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:
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 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: 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
Summary:
This diff extends bound domain to express Min/Max of another bounds, so it can keep some more
precision in `Math.min/max`.
limitation: `MinMaxB`, the constructor of the bound, can contain only linear expressions or
previous min/max expressions.
Reviewed By: ezgicicek
Differential Revision: D18395365
fbshipit-source-id: fc90d27fd
Summary: Capture locations where work is scheduled to run in parallel (here, just Executors). Also add a test file with cases the upcoming whole-program analysis for starvation should catch.
Reviewed By: dulmarod
Differential Revision: D18346880
fbshipit-source-id: 57411b052
Summary: Follow ups will include error messaging that makes the choice clear
Reviewed By: artempyanykh
Differential Revision: D18347664
fbshipit-source-id: b6f005726
Summary:
In this diff, we just load the info from the storage. Next diff will be
actually using this information to infer nullability.
`ThirdPartyAnnotationGlobalRepo.get_repo` will be used in the next diff,
hence #skipdeadcode
Reviewed By: artempyanykh
Differential Revision: D18347647
fbshipit-source-id: 82a9223c6
Summary:
This diff extends the alias domain, so each variable can have multiple aliases.
It changed `KeyLhs` can be mapped to multiple alias targets in the `AliasMap` domain:
```
before : KeyLhs.t -> KeyRhs.t * AliasTarget.t
after : KeyLhs.t -> KeyRhs.t -> AliasTarget.t
```
Reviewed By: ezgicicek
Differential Revision: D18062178
fbshipit-source-id: b325a6055
Summary:
This diff tries to make less imprecise division by constants results.
For example, the results of the division `[l, u] / c`, where `c` is a positive constant, are:
1. If `l/c` or `u/c` is representable in the bound domain, it uses the precise bounds, i.e., `[l/c, u/c]`.
2. If it is not representable, it tries to make conservative results:
if `0<=l<=u`, it returns `[0, u]` because `0 <= [l/c, u/c] <= u`
if `l<=u<=0`, it returns `[l, 0]` because `l <= [l/c, u/c] <= 0`
if `l<=0<=u`, it returns `[l, u]` because `l <= [l/c, u/c] <= u`
3. otherwise, it returns top, `[-oo, +oo]`
Reviewed By: ezgicicek
Differential Revision: D18270380
fbshipit-source-id: 8fb14c0e4
Summary:
Add precision to analysis by elaborating the thread-status domain. This is done by having unknown (bottom), UI, BG or Any (both/top) elements in the lattice. This way, when we branch on thread-identity (if I am on UI thread do this, otherwise do that), we know that in one branch we are on UI thread and on the other we are *not* on the UI thread (BG thread), where previously the other branch would just go to top.
With this knowledge we can throw away pairs that come from callees which run on a thread that is impossible, given the current caller thread identity. This can happen when annotations are used incorrectly, and since this is the purview of annot-reachability, we just drop those pairs entirely.
Reviewed By: skcho
Differential Revision: D18202175
fbshipit-source-id: be604054e
Summary:
Steal a page from RacerD (and improve interface of) on using certain calls to assert
execution on a particular thread. Reduces FPs and FNs too.
Reviewed By: dulmarod
Differential Revision: D18199843
fbshipit-source-id: 5bdff0dfe
Summary:
The zero cost of node does not make sense especially when the abstract memory is non-bottom. This
resulted in unreasonable zero cost results sometimes, e.g. when the checker could not find
appropriate control varaibles having interval values of iteration. This diff fixes this, so sets
the minimum basic cost as 1, if the abstract memory at the node is non-bottom.
Reviewed By: ezgicicek
Differential Revision: D18199291
fbshipit-source-id: b215d10e5
Summary:
This adds a more interesting value domain to pulse: concrete intervals.
There are still two main limitations:
1. arithmetic operations are all over-approximated: any assignment involving arithmetic operations is replaced by non-determinism
2. abstract values that are discovered to be equal are not merged into one
Reviewed By: skcho
Differential Revision: D18058972
fbshipit-source-id: 0492a590f
Summary:
This does several things because it was hard to split it more:
1. Split most of the arithmetic reasoning to PulseArithmetic.ml. This
doesn't need to be reviewed thoroughly because an upcoming diff
changes the domain from just `EqualTo of Const.t` to an interval domain!
2. When going through a prune node intra-procedurally, abduce arithmetic
facts to the pre (instead of just propagating them). This is the "assume
as assert" trick used by biabduction 1.0 too and allows to propagate
arithmetic constraints to callers.
3. Use 2 when applying summaries by pruning specs whose preconditions
have un-satisfiable arithmetic constraints.
This changes one of the tests! Pulse now does a bit more work to find
the false positive, as can be seen in the longer trace.
Reviewed By: skcho
Differential Revision: D18117160
fbshipit-source-id: af3b2c8c0
Summary:
Primitive types are not annotated. Because of that, we used to implicitly derive
`DeclaredNonnull` type for them. This worked fine, but this leads to errors in Strict mode, which does
not believe DeclaredNonnull type.
Now lets offifically teach nullsafe that primitive types are
non-nullable.
Reviewed By: jvillard
Differential Revision: D18114623
fbshipit-source-id: 227217931
Summary: It is now possible to push the thread status into each critical pair. This leads to higher precision, because when code branches on whether it is on the UI thread, the final abstract state of the procedure will be `AnyThread`, but pairs created in the UI thread branch should know that their status is `UIThread`, not `AnyThread`.
Reviewed By: jvillard
Differential Revision: D18114273
fbshipit-source-id: cbb99b46f
Summary:
This diff avoids making top values on unknown non-static function,
such as abstract function, calls. This is necessary because the
generated top values ruin the precision of the cost checker.
Reviewed By: ezgicicek
Differential Revision: D17418611
fbshipit-source-id: aeb759bdd
Summary:
The wrong function was used when we tried to see if the class is
annotated with NullsafeStrict. This made it work only for non-static
methods.
Now we use the proper way.
Reviewed By: ngorogiannis
Differential Revision: D18113848
fbshipit-source-id: 02b7555be
Summary:
Previously, we considered a function which modifies its parameters to be impure even though it might not be modifying the underlying value. This resulted in FPs like the following program in Java:
```
void fresh_pure(int[] a) {
a = new int[1];
}
```
Similarly, in C++, we considered the following program as impure because it was writing to `s`:
```
Simple* reassign_pure(Simple* s) {
s = new Simple{2};
return s;
}
```
This diff fixes that issue by starting the check for address equivalnce in pre-post not directly from the addresses of the stack variables, but from the addresses pointed to by these stack variables. That means, we only consider things to be impure if the actual values pointed by the parameters change.
Reviewed By: skcho
Differential Revision: D18113846
fbshipit-source-id: 3d7c712f3
Summary: We stop tracking at builder boundaries. Let's tract create methods as well so that trace is more informative.
Reviewed By: skcho
Differential Revision: D18038637
fbshipit-source-id: a99b6431f
Summary:
This is the first take on strict mode semantics.
The main invariant of strict mode is the following:
If the function passes `NullsafeStrict` check and its return value is
NOT annotated as Nullable, then the function does not indeed return
nulls, subject to unsoundness issues (which should either be fixed, or
should rarely happen in practice).
This invariant helps the caller in two ways:
1. Dangerous usages of non strict functions are visible, so the caller is enforced to check them (via assertions or conditions), or strictify them.
2. When the function is strict, the caller does not need to worry about
being defensive.
Biggest known issues so far:
1. Condition redundant and over-annotated warnings don't fully
respect strict mode, and this leads to stupid false positives. (There is
so much more stupid false positives in condition redundant anyway, so
not particularly a big deal for now).
2. Error reporting is not specific to mode. (E.g. we don't distinct real nullables and non-trusted non-nulls, which can be misleading). To be
improved as a follow up.
Reviewed By: artempyanykh
Differential Revision: D17978166
fbshipit-source-id: d6146ad71
Summary:
This is an intermediate nullability type powering future Strict mode.
See the next diff.
Reviewed By: artempyanykh
Differential Revision: D17977909
fbshipit-source-id: 2d5ab66d4
Summary: In preparation for improvements to the arithmetic reasoning.
Reviewed By: dulmarod
Differential Revision: D17977207
fbshipit-source-id: ee98e0772
Summary:
Domain for thread-type. The main goals are
- Track code paths that are explicitly on UI thread (via annotations, or assertions).
- Maintain UI-thread-ness through the call stack (if a callee is on UI thread then the
trace any call site must be on the UI thread too).
- If we are not on the UI thread we assume we are on a background thread.
- Traces with "UI-thread" status cannot interleave but all other combinations can.
- We do not track other annotations (eg WorkerThread or AnyThread) as they can be
erroneously applied -- other checkers should catch those errors (annotation reachability).
- Top is AnyThread, and is used as the initial state for analysis.
Interestingly, by choosing the right strategy for choosing initial state and applying callee summaries gets rid of some false negatives in the tests even though we have not introduced any path sensitivity yet.
Reviewed By: jvillard
Differential Revision: D17929390
fbshipit-source-id: d72871034
Summary:
bigmacro_bender
There are 3 ways pulse tracks history. This is at least one too many. So
far, we have:
1. "histories": a humble list of "events" like "assigned here", "returned from call", ...
2. "interproc actions": a structured nesting of calls with a final "action", eg "f calls g calls h which does blah"
3. "traces", which combine one history with one interproc action
This diff gets rid of interproc actions and makes histories include
"nested" callee histories too. This allows pulse to track and display
how a value got assigned across function calls.
Traces are now more powerful and interleave histories and interproc
actions. This allows pulse to track how a value is fed into an action,
for instance performed in callee, which itself creates some more
(potentially now interprocedural) history before going to the next step
of the action (either another call or the action itself).
This gives much better traces, and some examples are added to showcase
this.
There are a lot of changes when applying summaries to keep track of
histories more accurately than was done before, but also a few
simplifications that give additional evidence that this is the right
concept.
Reviewed By: skcho
Differential Revision: D17908942
fbshipit-source-id: 3b62eaf78
Summary:
Java method annotations are ambiguous in that there is no difference between
annotating the return value of a method, and annotating the method itself.
The disambiguation is done entirely based on the meaning of the annotation.
Here, while `UiThread`/`MainThread` are genuine method/class annotations
and not return annotations, the reverse is true for `ForUiThread`/`ForNonUiThread`.
This means that these latter annotations do not determine the thread status of
the method they are attached to.
Here we fix that misunderstanding.
Reviewed By: jvillard
Differential Revision: D17960994
fbshipit-source-id: 5aecfb124
Sungkeun Cho
Dulma Churchill
Ezgi Çiçek
Nikos Gorogiannis
Daiva Naudziuniene
Jules Villard
Mitya Lyubarskiy
Artem Pianykh
Radu Grigore
David Pichardie
Kfir Schindelhaim
Martin Trojer