Summary:
It turns out keeping attributes (such as invalidation facts) separate
from the memory is a bad idea and leads to loss of precision and false
positives, as seen in the new test (which previously generated a
report).
Allow me to illustrate on this example, which is a stylised version of
the issue in the added test: previously we'd have:
```
state1 = { x = 1; invalids={} }
state2 = { x = 2; invalids ={1} }
join(state1, state2) = { x = {1, 2}; invalids={{1, 2}} }
```
So even though none of the states said that `x` pointed to an invalid
location, the join state says it does because `1` and `2` have been
glommed together. The fact `x=1` from `state1` and the fact "1 is
invalid" from `state2` conspire together and `x` is now invalid even
though it shouldn't.
Instead, if we record attributes as part of the memory we get that `x`
is still valid after the join:
```
state1 = { x = (1, {}) }
state2 = { x = (2, {}) }
join(state1, state2) = { x = ({1, 2}, {}) }
```
Reviewed By: mbouaziz
Differential Revision: D12958130
fbshipit-source-id: 53dc81cc7
Summary:
I hear that this scheduler is better. I want the best scheduler
possible. Also pulse's join is a bit complex so it might matter one day.
whydididothis
Reviewed By: mbouaziz
Differential Revision: D12958131
fbshipit-source-id: 3bd77ccba
Summary: There is a bug on the instantiation of function parameters.
Reviewed By: mbouaziz
Differential Revision: D12973691
fbshipit-source-id: ca7fbc4e6
Summary: The aligned width of bool should be 1-byte, while the range of bool [0,1].
Reviewed By: jvillard
Differential Revision: D12932394
fbshipit-source-id: be1a5d6d1
Summary: For a general case of `operator=` we want to create a fresh location for the first parameter as `operator=` behaves as copy assignment.
Reviewed By: jvillard
Differential Revision: D12940635
fbshipit-source-id: 89c6e530d
Summary:
Whenever `vec.reserve(n)` is called, remember that the vector is
"reserved". When doing `vec.push_back(x)` on a reserved vector, assume
enough size has been reserved in advance and do not invalidate the
underlying array.
This gets rid of false positives.
Reviewed By: mbouaziz
Differential Revision: D12939837
fbshipit-source-id: ce6354fc5
Summary:
Instead of keeping at most one invalidation fact for each address, keep
a set of them and call them "attributes". Keeping a set of invalidation
facts is redundant since we always only want the smallest one, but
makes the implementation simpler, especially once we add more kinds of
attributes (used for modelling, see next diffs).
Reviewed By: mbouaziz
Differential Revision: D12939839
fbshipit-source-id: 4a54c2132
Summary:
Copied on the ownership checker logic: return the initial value of the
domain as return. This can probably be improved.
Reviewed By: mbouaziz
Differential Revision: D12888102
fbshipit-source-id: 9e2dac7fc
Summary:
When initialising a variable via semi-exotic means, the frontend loses
the information that the variable was initialised. For instance, it
translates:
```
struct Foo { int i; };
...
Foo s = {42};
```
as:
```
s.i := 42
```
This can be confusing for backends that need to know that `s` actually
got initialised, eg pulse.
The solution implemented here is to insert of dummy call to
`__variable_initiazition`:
```
__variable_initialization(&s);
s.i := 42;
```
Then checkers can recognise that this builtin function does what its
name says.
Reviewed By: mbouaziz
Differential Revision: D12887122
fbshipit-source-id: 6e7214438
Summary:
Now that arrays are dealt with separately (see previous diff), we can
turn the join back into an over-approximation as far as invalid
locations are concerned.
Reviewed By: skcho
Differential Revision: D12881989
fbshipit-source-id: fd85e49c0
Summary:
This prevents the join from wrongly assuming that we haven't seen a
variable on one side of the join.
Reviewed By: skcho
Differential Revision: D12881987
fbshipit-source-id: 42a776adb
Summary:
For more deduplications of issues, this diff loosens the condition of
similar bounds. The previous condition of similar bounds was too
strict, so [0,0] and [0,+oo] were not similar.
Depends on D10851762
Reviewed By: mbouaziz
Differential Revision: D10866127
fbshipit-source-id: 4ba912a88
Summary: For `operator=(lhs, rhs)` we want to model it as an assignment if rhs is materialized temporary created in the constructor.
Reviewed By: jvillard
Differential Revision: D10462510
fbshipit-source-id: 998341e69
Summary: Do not create a new location for placement new argument if it already exists.
Reviewed By: jvillard
Differential Revision: D12839942
fbshipit-source-id: 758b67a82
Summary:
In order to know whether a global variable is an integral constant
expression in C, this diff adds a field for the results of isInitICE.
The controller you requested could not be found.: facebook-clang-plugins
Reviewed By: mbouaziz
Differential Revision: D12838521
fbshipit-source-id: 388bff1f3
Summary:
Get rid of `USE_AFTER_LIFETIME`. This could be useful to deploy pulse
alongside the ownership checker too.
Reviewed By: da319
Differential Revision: D12857477
fbshipit-source-id: 8e2a2a37c
Summary:
Keep `USE_AFTER_LIFETIME` for unclassified errors (for now it contains
vector invalidation too because I can't think of a good name for
them, and maybe it makes sense to wait until we have more types of them
to decide on a name).
Reviewed By: da319
Differential Revision: D12825060
fbshipit-source-id: bd75ef698
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
Sungkeun Cho
Dino Distefano
Jules Villard
Ezgi Çiçek
Mehdi Bouaziz
Daiva Naudziuniene
Martin Trojer