Summary:
Bottom bounds do not make sense (what is the meaning of `[_|_; 1]`?), let's get rid of them.
`Bot` was useful for substitution though, with a special meaning, use `bottom_lifted` for that case.
Reviewed By: skcho
Differential Revision: D5941796
fbshipit-source-id: 5778255
Summary:
The interval bound of the abstract domain is extended.
`[min|max](int, symbol)` => `int [+|-] [min|max](int, symbol)`
As a result, `vector::empty` can be modelled to return a more precise value: `1 - min(1, size)`.
Reviewed By: mbouaziz
Differential Revision: D5899404
fbshipit-source-id: c8c3f49
Summary:
Read the documentation and it doesn't seem like these functions are guaranteed to choose the same value in different runs.
I hypothesize that these may be the source of flakiness in the thread-safety tests/smoke tests.
Reviewed By: jvillard
Differential Revision: D5794384
fbshipit-source-id: 02b7a96
Summary:
This commit avoids precision loss on pruning.
// x -> [s$1, s$2]
if(x) { ... }
// x -> ?
before: x -> [min(0, s$1), max(0, s$2)]
because two x values, [0, 0] (true case) and [s$1, s$2] (false case), were joined after the if branch.
after: x -> [s$1, s$2]
Reviewed By: mbouaziz
Differential Revision: D5431009
fbshipit-source-id: 14a9efe
Summary:
Problem: The analyzer did not know that the value of `v.size()` is an alias of `v.infer_size`, so `v.infer_size` is not pruned by the if condition. As a result it raises a false alarm.
void safe_access(std::vector<int> v) {
if (v.size() >= 10) {
v[9] = 1; // error: BUFFER_OVERRUN Offset: [9, 9] Size: [5, 5]
}
}
void call_safe_access_Good() {
std::vector<int> v(5, 0);
safe_access(v);
}
Solution: Adding alias for return value to the abstract domain.
Now Inferbo can prune `v.infer_size` because it knows that the value of `v.size()` is an alias of `v.infer_size`. There is already an alias domain in Inferbo, so we added a specific room for the retrun value.
Reviewed By: jvillard, mbouaziz
Differential Revision: D5396988
fbshipit-source-id: 4a4702c
Summary:
Conversion and reformat of infer source using ocamlformat
auto-formatting tool.
Current status:
- Because Reason does not handle docstrings, the output of the
conversion is not 'Warning 50'-clean, meaning that there are
docstrings with ambiguous placement. I'll need to manually fix
them just before landing.
Reviewed By: jvillard
Differential Revision: D5225546
fbshipit-source-id: 3bd2786
Summary:
It instantiates fields of structures when a pointer to which is given
as a function parameter, e.g., `foo(&s);`.
Reviewed By: mbouaziz, jvillard
Differential Revision: D5337645
fbshipit-source-id: c06da29
Summary: Allow type variables in `Typ.desc`. It will be used to store template type arguments.
Reviewed By: jberdine
Differential Revision: D5154757
fbshipit-source-id: 55b8e81
Summary:
This commit fixes a problem that the buffer overrun checker incorrectly
stops when a global variable (bottom) is involved in control flow.
In the new version, abstract memories return Top for unanalyzed abstract
variables.
Reviewed By: mbouaziz
Differential Revision: D5016447
fbshipit-source-id: 5132448
Summary:
An array has a static or dynamic length (number of elements), but it also has a
stride, determined by the type of the element: `sizeof(element_type)`. We don't
have a good `sizeof()` function available on SIL types, so record that stride
in the array type.
update-submodule: facebook-clang-plugins
Reviewed By: mbouaziz
Differential Revision: D4969697
fbshipit-source-id: 98e0670
Summary:
Modify the type of `Exp.Sizeof ...` to include the value that the expression
evaluates to according to the compiler, or None if it cannot be known
statically.
Use this information in inferbo.
Mostly unused in the BiAbduction checker for now, although it could be useful
there too.
update-submodule: facebook-clang-plugins
Reviewed By: mbouaziz
Differential Revision: D4953634
fbshipit-source-id: be0999d
Summary:
Bottom means unreachable, not unknown.
Replace Bottom by Top in:
- unknown procedure return value
- unknown constant
- closure, exceptions
- when there are more formals than actuals
Depends on D4961989
Reviewed By: KihongHeo
Differential Revision: D4962006
fbshipit-source-id: e2a153d
Summary:
- Bottom-lift abstract memory domain to express unreachable node
- Two cases to make a node unreachable
+ constant: when an evaluation result of condition expression is
bottom or false, e.g., "prune(0)".
+ alias: when the same structure e is compared to itself with "<",
">", and "!=", e.g., "prune(e < e)".
- Add test for the new prune (prune_constant.c, prune_alias.c)
- Debug the semantics of comparison
Reviewed By: mbouaziz
Differential Revision: D4938055
fbshipit-source-id: d0fadf0
Summary:
Polymorphic models, and type environment refinements, need mutual
references between general types and struct types.
Reviewed By: cristianoc
Differential Revision: D4620076
fbshipit-source-id: f9d01e6
Mehdi Bouaziz
Sungkeun Cho
Sam Blackshear
Josh Berdine
Kihong Heo
Andrzej Kotulski
Jules Villard
Kihong Heo
Cristiano Calcagno