Summary:
Getting this right will be long and complex so for now the easiest is to
underreport and only consider as invalid the addresses we know to be invalid on
both sides of a join. In fact the condition for an address to be invalid after
a join is more complex than this: it is invalid only if *all* the addresses in
its equivalence class as discovered by the join are invalid.
Reviewed By: skcho
Differential Revision: D12823925
fbshipit-source-id: 2ca109356
Summary: Similarly as for destructors, we provide an address of an object as a first parameter to constructors. When constructor is called we want to create a fresh location for a new object.
Reviewed By: jvillard
Differential Revision: D10868433
fbshipit-source-id: b60f32953
Summary: We provide an address of an object as a parameter to destructor. When destructor is called the object itself is invalidated, but not the address.
Reviewed By: jvillard
Differential Revision: D12824032
fbshipit-source-id: 516eebcf8
Summary:
It terminates narrowing when new and old states are not comparable.
Since current narrowing does not use meet operations guaranteeing
termination of narrowing, it tries to terminate narrowing more
conservatively.
Reviewed By: mbouaziz
Differential Revision: D12815419
fbshipit-source-id: e8b45199e
Summary: It tries division on minmax value approximately, rather than just returning infinities. For example, `[0,2+min(6,s)] / 2` returns `[0,4]`.
Reviewed By: mbouaziz
Differential Revision: D10867091
fbshipit-source-id: d3f49987b
Summary:
This diff preserves values of offset and index separately, rather than
one value of their addition, because premature addition results in
imprecise FPs by the limited expressiveness of the domain.
Reviewed By: mbouaziz
Differential Revision: D10851393
fbshipit-source-id: 1685ead36
Summary:
The time has come to keep track of which tests pass and which are FP/FN
for pulse.
Reviewed By: mbouaziz
Differential Revision: D10854064
fbshipit-source-id: 60938e48f
Summary:
Turns out once a vector array became invalid it stayed that way, instead
of the vector getting a new valid internal array.
Reviewed By: skcho
Differential Revision: D10853532
fbshipit-source-id: f6f22407f
Summary:
Now the domain can reason about `&` and `*` too. When recording `&`
between two locations also record a back-edge `*`, and vice-versa.
Reviewed By: mbouaziz
Differential Revision: D10509335
fbshipit-source-id: 8091b6ec0
Summary: This is more flexible and allows us to give more details when reporting.
Reviewed By: mbouaziz
Differential Revision: D10509336
fbshipit-source-id: 79c3ac1c8
Summary: To avoid reporting on private methods, ignore those starting with underscore. Other cleanups.
Reviewed By: jvillard
Differential Revision: D10558970
fbshipit-source-id: 0572f1e70
Summary:
Invalidating addresses for destructors to catch use after destructor errors.
To pass ownership tests for use after destructor errors, we still need to:
(1) fix pointer arithmetic false positives
(2) add model for placement new to fix false positives
(3) add model for operator= to fix false positives
(4) support inter-procedural analysis for destructor_order_bad test
Reviewed By: jvillard
Differential Revision: D10450912
fbshipit-source-id: 2d9b1ee68
Summary:
It uses platform-dependent integer type widths information when
constructing Sizeof expressions which have a field(`nbytes`)
representing the static results of the evaluation of `sizeof(typ)`.
Reviewed By: mbouaziz
Differential Revision: D10504715
fbshipit-source-id: 0c79d37d8
Summary: Reports will now be issued for the class loads of the methods specified by the option `--class-loads-roots`.
Reviewed By: jvillard
Differential Revision: D10466492
fbshipit-source-id: 91456d723
Summary:
Instead of the non-sensical piecewise join we had until now write
a proper one. Hopefully the comments explain what it does. Main one:
```
(* high-level idea: maintain some union-find data structure to identify locations in one heap
with locations in the other heap. Build the initial join state as follows:
- equate all locations that correspond to identical variables in both stacks, eg joining
stacks {x=1} and {x=2} adds "1=2" to the unification.
- add all addresses reachable from stack variables to the join state heap
This gives us an abstract state that is the union of both abstract states, but more states
can still be made equal. For instance, if 1 points to 3 in the first heap and 2 points to 4
in the second heap and we deduced "1 = 2" from the stacks already (as in the example just
above) then we can deduce "3 = 4". Proceed in this fashion until no more equalities are
discovered, and return the abstract state where a canonical representative has been chosen
consistently for each equivalence class (this is what the union-find data structure gives
us). *)
```
Reviewed By: mbouaziz
Differential Revision: D10483978
fbshipit-source-id: f6ffd7528
Summary:
It avoids checking integer overflow when it definitely cannot happen.
For example, it does not check integer overflow of addition when one
of parameters is a negative number, or underflow of subtraction when
its first parameter is a positive number.
Reviewed By: mbouaziz
Differential Revision: D10446161
fbshipit-source-id: b8c86e1b2
Summary: We assume multiplication of 1 is safe. It happens sometimes by multiplying `sizeof(char)`.
Reviewed By: mbouaziz
Differential Revision: D10444680
fbshipit-source-id: 2f33be280
Summary: This diff changes pp of binary operation condition in order to avoid a `make test` failure. For the same `uint64_t` type, it is translated to `unsigned long long` in 64bit mac, but `unsigned long` in 64bit linux, which made a `make test` failure.
Reviewed By: mbouaziz
Differential Revision: D10459466
fbshipit-source-id: 449ab548e
Summary:
`Location` was clashing with the `Location` module, so use `Address`
instead.
When invalidating an address, remember the "actor" of its invalidation,
i.e. the access expression leading to the address and the source
location of the corresponding instruction.
When checking accesses, also pass the actor responsible for the access,
so that when we raise an error we know:
1. when and why a location was invalidated
2. when and why we tried to read it after that
Reviewed By: mbouaziz
Differential Revision: D10446282
fbshipit-source-id: 3ca4fb3d4
Summary:
Model `x[y]` and `x.push_back(i)` to catch the classic bug of "take
reference inside vector, invalidate, then use again".
Reviewed By: da319
Differential Revision: D10445824
fbshipit-source-id: 21ffd9677
Summary:
Do the intersection of the heap and stack domains, and the union of the
invalid location sets. This forgets invalid locations that appear only
in one heap, unfortunately. We can start with this and improve later.
Reviewed By: mbouaziz
Differential Revision: D10445825
fbshipit-source-id: cc24460af
Summary:
New analysis in foetal form to detect invalid use of C++ objects after their
lifetime has ended. For now it has:
- A domain consisting of a graph of abstract locations representing the heap, a map from program variables to abstract locations representing the stack, and a set of locations known to be invalid (their lifetime has ended)
- The heap graph is unfolded lazily when we resolve accesses to the heap down to an abstract location. When we traverse a memory location we check that it's not known to be invalid.
- A simple transfer function reads and updates the stack and heap in a rudimentary way for now
- C++ `delete` is modeled as adding the location that its argument resolves to to the set of invalid locations
- Also, the domain has a really crappy join and widening for now (see comments in the code)
With this we already pass most of the "use after delete" tests from the
Ownership checker. The ones we don't pass are only because we are missing
models.
Reviewed By: mbouaziz
Differential Revision: D10383249
fbshipit-source-id: f414664cb
Summary:
It avoids raising an exception when unexpected arguments are given to
placement new. We will revert this after fixing the frontend to parse
user defined `new` correctly in the future.
Reviewed By: mbouaziz
Differential Revision: D10378136
fbshipit-source-id: d494f781b
Jules Villard
Daiva Naudziuniene
Sungkeun Cho
Mehdi Bouaziz
Dino Distefano
Nikos Gorogiannis
Martin Trojer