Summary:
Array types where the length is not statically known were represented
using fresh variables. This diff:
- Makes array type length optional, reducing the amount of work needed
for renaming, substitution, and normalization.
- Revises uses of array length so that the length component of a
Tarray type represents only the statically determined constant
length of an array type, and the length component of a Sizeof
expression represents the dynamically determined length of an array
value.
- Restricts the type of static lengths from a general expression
(Sil.exp) to an integer (Sil.Int.t), enforcing that static types are
constant. This in particular ensures that types contain no
variables, and so are invariant under operations such as renaming
and substitution.
- Removes the type substitution and renaming functions typ_sub,
typ_normalize, and typ_captured_ren. Now that array type lengths
are constant integers, all of these functions are the identity.
Reviewed By: cristianoc
Differential Revision: D3387343
fbshipit-source-id: b5db768
Summary:
The philosophy of the tracing mode reporting is to not report the errors in a method if reaching this error does depend on information that can be false at call site. Typically with:
void foo(Object obj, int x) {
if (x == 3) {
obj.toString();
}
}
it may be that we always call `foo` with a non-null parameter or `x != 3`.
Thechnically, the reporting code matches the pairs of the form (precondition, error) and filtering out the cases where the precondtions was not imposing constraints on the calling context, and report the other cases. So the NPE could be reported in the following case:
void bar() {
foo(null, 3);
}
However, we were missing the case where there was anyway no way to call a method in a safe way, i.e. all the preconditions were of the form: (precondition, error), for example:
void baz(boolean b) {
if (b) {
foo(null, 3);
} else {
foo(null, 3);
}
}
In that case, the summary is of the form
PRE (1): b = false
POST: NullPointerException
PRE (2): b = true
POST: NullPointerException
In which case it is legit to report `NullPointerException` in `baz`.
Reviewed By: sblackshear, jberdine
Differential Revision: D3220501
fb-gh-sync-id: 7fb7d70
fbshipit-source-id: 7fb7d70
Summary: Example of dynamic dispatch with interfaces were already working. Adding some tests now so that we don't break this.
Reviewed By: sblackshear
Differential Revision: D3220360
fb-gh-sync-id: 11395dd
fbshipit-source-id: 11395dd
Summary:public
Lazy dynamic dispatch handling works as follows:
Assuming a call of the form:
foo(a);
where the static type of `a` is `A`. If during the symbolic execution, the dynamic type of the variable `a` is `B` where `B <: A`, then we create on-demand a copy `foo(B)` of `foo(A)` where all the uses of the typed parameter `a` are replaced with a parameter of type `B`. Especially, if `foo` contains virtual call, say `get` where `a` is the receiver, then the call gets redirected to the overridden method in `B`, which simulates the runtime behavior of Java.
This lazy dynamic dispatch mode is only turn on for the tracing mode for now in order to avoid conflicts with sblackshear's approach for sound dynamic dispatch.
Reviewed By: sblackshear
Differential Revision: D2888922
fb-gh-sync-id: 3250c9e
shipit-source-id: 3250c9e
Summary:
public
Lines other than the first of multi-line comments in non-ocaml files
were flush right instead of aligned.
Reviewed By: jvillard
Differential Revision: D2739752
fb-gh-sync-id: c85f56e
Josh Berdine
Sam Blackshear
Jeremy Dubreil
Cristiano Calcagno
Open Source Synchronization