Summary:
This makes reports more readable: they were all at the end of functions,
currently.
This is actually quite tricky to do as it involves detecting which
locations are unreachable.
Some of this logic can/should probably be shared with
`AbductiveDomain.discard_unreachable` but at the moment that's not the
case.
Reviewed By: skcho
Differential Revision: D28382590
fbshipit-source-id: bd4239a0c
Summary: Objective-C dispatch methods are not specialized, but have a special case during symbolic execution in biabduction. Reuse the same approach for Pulse: retrieve the given block name and its arguments and call it.
Reviewed By: skcho
Differential Revision: D28550468
fbshipit-source-id: 5017bb71e
Summary:
Most/all of the time we expect the history of the value to faithfully
trace how it got allocated. That history was then added as a prefix of
the trace leading to the same place, leading to duplicate information in
the report trace.
We may need to do the same for other bug types.
Reviewed By: ezgicicek
Differential Revision: D28536891
fbshipit-source-id: a83a2d038
Summary:
Turns out the mistake was pretty simple: we just forgot to keep the
history of the return value in the callee and add it to the caller's.
Reviewed By: skcho
Differential Revision: D28385941
fbshipit-source-id: 40fe09c99
Summary:
When garbage-collecting addresses we would also remove their attributes.
But even though the addresses are no longer allocated in the heap, they
might show up in the formula and so we need to remember facts about
them.
This forces us to detect leaks closer to the point where addresses are
deleted from the heap, in AbductiveDomain.ml. This is a nice refactoring
in itself: doing so fixes some other FNs where we sometimes missed leak
detection on dead addresses.
This also makes it unecessary to simplify InstanceOf eagerly when
variables get out of scope.
Some new {folly,std}::optionals false positives that either are similar to existing ones or involve unmodelled smart pointers.
Reviewed By: da319
Differential Revision: D28126103
fbshipit-source-id: e3a903282
Summary:
As explained in the previous diff: when the access trace goes through
the invalidation step there is no need to print the invalidation trace
at all.
Note: only a few sources of invalidation are handled at the moment. The
following diffs gradually fix the other sources of invalidation.
Reviewed By: skcho
Differential Revision: D28098335
fbshipit-source-id: 5a5e6481e
Summary:
The eventual goal is to stop having separate sections of the trace
("invalidation part" + "access part") when the "access part" already
goes through the invalidation step. For this, it needs to record when a
value is made invalid along the path.
This is also important for assignements to NULL/0/nullptr/nil: right now
the way we record that 0 is not a valid address is via an attribute
attached to the abstract value that corresponds to 0. This makes traces
inconsistent sometimes: 0 can appear in many places in the same function
and we won't necessarily pick the correct one. In other words, attaching
traces to *values* is fragile, as the same value can be produced in many
ways. On the other hand, histories are stored at the point of access, eg
x->f, so have a much better chance of being correct. See added test:
right now its traces is completely wrong and makes the 0 in `if
(utf16StringLen == 0)` the source of the NULL value instead of the
return of `malloc()`!
This diff makes the traces slightly more verbose for now but this is
fixed in a following diff as the traces that got longer are those that
don't actually need an "invalidation" trace.
Reviewed By: skcho
Differential Revision: D28098337
fbshipit-source-id: e17929259
Summary:
This diff avoids dereference of C struct, in its frontend and its semantics of Pulse. In SIL, C
struct is not first-class value, thus dereferencing on it does not make sense.
Reviewed By: ezgicicek
Differential Revision: D27953258
fbshipit-source-id: 348d56338
Summary: This diff copies each field values inside setter/getter of ObjC.
Reviewed By: ezgicicek
Differential Revision: D27940521
fbshipit-source-id: 9977cae75
Summary:
When a block value is passed via more than one-depth of function calls, it is not analyzed correctly
because current inlining mechanism (specializing objc block parameters) of the frontend works for
only one-depth of block passing. This diff gives up analyzing initialized-ness of captured
variables in ObjC to avoid FPs.
Reviewed By: da319
Differential Revision: D27885395
fbshipit-source-id: fc6b4663c
Summary: The translation of captured by reference variables has been fixed for ObjC blocks (D26945575 (778c629401)), so we do not need to ignore them in uninit analysis anymore.
Reviewed By: skcho
Differential Revision: D27063663
fbshipit-source-id: 447084d37
Summary: Variables captured by reference do not have correct type in objc blocks. They are missing one reference. This diff sets the correct type of captured reference variables inside procdesc, similarly as we already have for cpp lambdas. The translation of block's body will then take into account the type of captured variable from procdesc.
Reviewed By: ezgicicek
Differential Revision: D26945575
fbshipit-source-id: 06a9d9cc6
Summary:
Adapting error messages in Pulse so that they become more intuitive for
developers.
Reviewed By: jvillard
Differential Revision: D26887140
fbshipit-source-id: 896970ba2
Summary: This diff revises the trace generation of the uninitialized value checker, by introducing a new diagnostics for it.
Reviewed By: jvillard
Differential Revision: D25433775
fbshipit-source-id: 1279c0de4
Summary: This diff gives semantics of dispatch_sync to call the closure parameter.
Reviewed By: jvillard
Differential Revision: D25423175
fbshipit-source-id: a45309073
Summary:
This diff supports inter-procedural uninit analysis in pulse.
* Added `MustBeInitialized` attribute to pre state when an address is read
* Remove `Uninitialized` attribute when callee has `WrittenTo` for the
same address
Reviewed By: jvillard
Differential Revision: D25368492
fbshipit-source-id: cbc74d4dc
Summary:
This diff adds uninitialized value check in pulse. For now, it supports only simple cases,
- declared variables with a type of integer, float, void, and pointer
- malloced pointer variables that points to integer, float, void, and pointer
TODOs: I will add more cases in the following diffs.
- declared/malloced array
- declared/malloced struct
- inter-procedural checking
Reviewed By: jvillard
Differential Revision: D25269073
fbshipit-source-id: 317df9a85
Summary:
This diff finishes the migration from the specialization of methods that take blocks as arguments. Here we delete all the old code and change the way we model dispatch functions so that the tests pass.
- Remove the code for specializing the methods in biabduction.
- Remove the call flags `cf_with_block_parameters` that was only used in this algorithm.
- Removes models for dispatch functions.
- Adds models for dispatch functions as program transformation only in biabduction. To be added in other checkers in the future.
Reviewed By: ngorogiannis
Differential Revision: D23345342
fbshipit-source-id: b5e8542ce
Summary: In the frontend captured variables for blocks are added as formal parameters in procdesc at the beginning.
Reviewed By: dulmarod
Differential Revision: D23163619
fbshipit-source-id: 2bcbe9b9c
Summary:
This will allow all the analyses to be able to call closures without any special treatment: we transform the call to variables that point to closures into normal function calls. We treat only ObjC blocks at the moment, with C++ lambdas to be done as a next step.
We aimed to achieve certain results in Pulse (see tests: avoid memory leaks and NPEs FPs) while also keeping the biabduction analysis working as before.
We also checked that for the examples analyzed Pulse behaves like the correct semantics of ObjC programs with blocks.
Reviewed By: jvillard
Differential Revision: D22547333
fbshipit-source-id: efe56ed51
Summary:
We update the type of captured variables to include information about capture mode (`ByReference` or `ByValue`) both for procdesc attributes and the closure expression.
For lambda: closure expression now contains correct capture mode for capture variables. Procdesc still does not contain information about captured variables which we will address in the next diff.
For objc blocks: at the moment all captured variables have mode `ByReference`. Added TODOs to fix this.
Reviewed By: jvillard
Differential Revision: D22572054
fbshipit-source-id: 4c88678ee
Summary:
This model is very important in the analysis of ObjC classes because the pattern
```
- (instancetype)init {
if (self = [super init]) {
...
}
return self;
}
```
is very common, so we need to know that if the super class is `NSObject`, the implementation of `init` is returning `self`, otherwise it's a skip function and we don't get the correct spec for the function. We fix some memory leak FP with this model, see test.
Reviewed By: ezgicicek
Differential Revision: D22259281
fbshipit-source-id: 3ee48c827
Summary: These models for Memory Leaks have been ported to Pulse, so we can remove the models in biabduction and corresponding tests.
Reviewed By: skcho
Differential Revision: D22206287
fbshipit-source-id: e17499ad3
Summary: The new memory leaks analysis is now ready to be enabled by default and turned on in production. This also replaces the biabduction one which is now disabled.
Reviewed By: jvillard
Differential Revision: D21998666
fbshipit-source-id: 9cd95e894
Summary:
This models ARC implementation of dealloc, see https://clang.llvm.org/docs/AutomaticReferenceCounting.html#dealloc. Dealloc methods can be added to ObjC classes to free C memory for example, but the deallocation of the ObjC instance variables of the object is done automatically. So here we add this explicitly to Infer:
1. First, we add an empty dealloc method when it is not written explicitly.
2. For each dealloc method (including the implicitly added ones) we add calls to dealloc of the ObjC instance variables.
Reviewed By: jvillard
Differential Revision: D21883546
fbshipit-source-id: f5d4930f2
Summary:
This diff implements part of the memory management for Objective-C classes in ARC, namely that `dealloc` is called when the objects become unreachable. In reality the semantics of ARC says that this happens when their reference count becomes 0, but we are not modelling this yet in Pulse. However, we could in the future.
This fixes false positives memory leaks when the memory is freed in dealloc.
`dealloc` is often implicit in Objective-C, it also calls the dealloc of instance variables and superclass. None of this is implemented yet, and will be done in a future diff. This will be added in the frontend probably, similarly to how it's done for C++ destructors.
This is an important part of modelling Objective-C semantics in Infer, I looked at whether this should be a preanalysis to be used by all analyses but this needs Pulse. So the idea is that any analysis that needs to understand Objective-C memory model well, should have Pulse as a preanalysis.
Reviewed By: jvillard
Differential Revision: D21762292
fbshipit-source-id: ced014324
Summary:
This function had been computing the name for ObjC methods wrong, with only the class name. This was causing wrong error messages in Pulse.
The main issue was that `Procname.to_simplified_string` was writing `Classname::methodname` for ObjC methods, which is not the convention. This confused the `hashable_name` funtion. So changing the method name to `Classname.methodname` which is more standard, and this also fixes `hashable_name`.
Reviewed By: ngorogiannis, jvillard
Differential Revision: D21570880
fbshipit-source-id: 13ed62cf8
Summary:
Just like `CFBridgingRelease` we want to be able to model functions that are specific to a given codebase that make a transfer of memory ownership so that developers don't need to worry about releasing that memory anymore, and hence, we don't want to report leaks on that memory.
Things get a little more complicated, because some of the functions we want to model are in a specific namespace, so with this flag we take both cases into account, when we are dealing with namespaces or not.
Reviewed By: jvillard
Differential Revision: D21404409
fbshipit-source-id: c36bd7afc
Summary:
Because in the real semantics CFRelease can be used more than once, and also the variables can be used after CFRelease in general, modelling this as `free` causes many `USE_AFTER_FREE` errors. Now we change the model to not add the `Invalid CFree` attribute, but to just remove the `Allocated` attribute. So we can model memory leaks in the simple case of `Create` and not `CFRelease` before going out of scope, but we avoid the `USE_AFTER_FREE`.
Since the model for CFRelease now diverges from free, changed the command line option for modelling to `pulse-model-release-pattern`.
Reviewed By: jvillard
Differential Revision: D21324895
fbshipit-source-id: ab323d981
Summary: We currently don't support abducing the spec that we need to delete an attribute, that makes the model for `CFBridgingRelease` work les well when it is, for instance, wrapped in a method. We show examples of how this doesn't work at the moment.
Reviewed By: jvillard
Differential Revision: D21176108
fbshipit-source-id: 79aed7a5d
Summary:
We model `malloc` in Objective-C as `malloc_not_fail` I think because the null case is not normally handled in iOS apps because the OS will just killed the app after giving some memory warnings.
So adding `malloc_not_fail` model to Pulse.
Reviewed By: jvillard
Differential Revision: D21278527
fbshipit-source-id: 17a5008fe
Summary:
This translates the construct `ObjCBridgedCastExpr` when the cast_kind is `OBC_BridgeTransfer`, or in syntax, the cast (`__bridge_transfer`).
This cast means that the object is passed from manual memory management to ARC, so one doesn't need to call `release` manually. It is important to model this to avoid false positives.
It translates it as a builtin that we then model in Pulse, the same way we modelled `CFBridgingRelease` which does the same thing.
The name of the builtin is `__free_cf` which is not ideal but I left it like that for compatibility with biabduction. We can change it once we remove this check from biabduction.
update-submodule: facebook-clang-plugins
Reviewed By: jvillard
Differential Revision: D21176337
fbshipit-source-id: 736ceeb9b
Summary: `CFBridgingRelease` and `__bridge_transfer` which I'll model later, transfer the memory model from manual memory ref count to ARC (automatic ref count), so to avoid false positives this needs to be modelled. We can simply remove the Allocated attribute from the state, which means we won't try to track that memory anymore.
Reviewed By: skcho
Differential Revision: D21088218
fbshipit-source-id: 3520a0d59
Summary: Unify the models of malloc and for the Create and Copy functions for Core Graphics. This add the null case from the malloc model to the Core Graphics models.
Reviewed By: jvillard
Differential Revision: D20890956
fbshipit-source-id: 278ac9d2f
Summary: Modelling `CG.*Release ` and `CFRelease` as `free`. This is what we were doing in biabduction.
Reviewed By: skcho
Differential Revision: D20767174
fbshipit-source-id: c77c1cdc6
Summary:
This models all the Create and Copy functions from CoreGraphics, examples in the tests.
These functions all allocate memory that needs to be manually released.
The modelling of the release functions will happen in a following diff. Until then, we have some false positives in the tests.
This check is currently in biabduction, and we aim to move it to Pulse.
Reviewed By: jvillard
Differential Revision: D20626395
fbshipit-source-id: b39eae2d9
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
Jules Villard
Daiva Naudziuniene
Sungkeun Cho
Gabriela Cunha Sampaio
Dulma Churchill