Summary:
The previous code would call the destructor for the C++ temporary
*before* the prune nodes, which then try to dereference it. Wrong.
Quick fix: don't destroy temporaries in conditionals.
Reviewed By: mbouaziz
Differential Revision: D16030735
fbshipit-source-id: e11abad58
Summary:
Similar to D16005395: `folly::Optional` has a boolean field to know if
it needs to destroy the wrapped object and pulse ignores that
completely, causing false positives each time an `Optional` is created
around something with a non-trivial destructor.
Reviewed By: mbouaziz
Differential Revision: D16030149
fbshipit-source-id: aeed4a0b3
Summary:
We were skipping some instructions before and that was a problem for
pulse. See added pulse test.
Reviewed By: mbouaziz
Differential Revision: D16030150
fbshipit-source-id: 9c62e6213
Summary: Not sure if anyone uses this but there, now it's modelled.
Reviewed By: mbouaziz
Differential Revision: D16008162
fbshipit-source-id: f4795dcba
Summary:
Prevent false positives about variables captured by value gone out of
scope.
Reviewed By: ezgicicek
Differential Revision: D16008165
fbshipit-source-id: d70e47db4
Summary: We know how to do interprocedural calls so let's use that!
Reviewed By: mbouaziz
Differential Revision: D16008164
fbshipit-source-id: 4c34bf704
Summary:
`function::operator=` is called whenever we assign a literal lambda to a
variable, so it's pretty useful to be able to report anything on
lambdas.
Reviewed By: mbouaziz
Differential Revision: D16008163
fbshipit-source-id: a9d07668d
Summary:
The previous version had a potentially exponential behavior on values with already lots of sharing.
This is fixed here at the price of a multiplicative constant factor (cost of `Hashtbl.hash`).
It also prepares for the handling of cycles.
Reviewed By: ngorogiannis
Differential Revision: D16016906
fbshipit-source-id: 611287917
Summary:
In light of Pulse's misadventures with HIL, leave a warning for future
checkers writers. Comment mostly taken from summary of D15824961.
Reviewed By: ngorogiannis
Differential Revision: D16005392
fbshipit-source-id: 805f17584
Summary:
This can take a minute or so during which the user would have no idea
what infer is doing.
Reviewed By: ngorogiannis
Differential Revision: D16005393
fbshipit-source-id: 586812527
Summary:
No need to hide the real reason for the crash behind another crash when
trying to print the error message.
Reviewed By: mbouaziz, ngorogiannis
Differential Revision: D16005394
fbshipit-source-id: dc3d9437e
Summary:
The constructor of `folly::SocketAddress` conditionally deletes some
object and then makes that condition false. The destructor then does the
same. Pulse ignores conditionals so will see a double delete.
Just skip that function for now, but it should be easy for pulse to be
more correct here if it knew how to compare constant values.
Reviewed By: mbouaziz
Differential Revision: D16005395
fbshipit-source-id: 036f5091b
Summary:
Printing `Exp.Const (Cfun proc_name)` adds `_fun_` in front of the
procedure name, eg `_fun_foo` instead of `foo`. This showed up in pulse
traces.
Reviewed By: mbouaziz
Differential Revision: D16004606
fbshipit-source-id: 72ac6866f
Summary:
Fixes a false positive where the address of a C++ temporary is bound to
a static const reference variable then returned. The fix doesn't try to
establish that the variable is a const reference so could lead to false
negatives but that can be addressed later.
Reviewed By: ezgicicek
Differential Revision: D16004538
fbshipit-source-id: e403dbefe
Summary:
Replace Hashtbl.clear with Hashtbl.reset
This saves memory because the reset method shrinks the hash-table, whereas the clear method just empties it
Reviewed By: jvillard
Differential Revision: D16004966
fbshipit-source-id: f32b00b0f
Summary:
[apologies for the unreviewable diff...]
Get rid of HIL expressions in pulse. This finishes the HIL -> SIL
migration. The first step made pulse start from SIL instructions but
would translate most accesses to HIL to re-use most of the existing
pulse code. This diff gets rid of the intermediate translation of SIL
expressions to HIL expressions.
Big changes:
1. `PulseOperations` mostly rewritten, driven by using `Exp.t` instead of `HilExp.AccessExpression.t` for everything.
2. Stop trying to reverse-engineer what addresses mean in terms of
access paths from program variables. Rely on the trace pointing at
the right places in the code to be enough. This is because it wasn't
that useful (and could even be misleading when wrong) but could be
prohibitively expensive in degenerate cases (eg nodes with tens of
thousands of successive array accesses...)
3. `PulseAbductiveDomain.apply_post` now returns the computed return
value instead of recording it itself.
4. Change of vocabulary: `materialize` -> `eval`, `crumb` -> `event`
5. Function calls arguments are now evaluated prior to doing anything
else, which saves everything else from having to (remember to) do
that. In particular, this changes how models look quite a bit.
Reviewed By: mbouaziz
Differential Revision: D15986373
fbshipit-source-id: 1d79935de
Summary:
Passing an absolute project path as buck config flag makes buck caching almost impossible for infer artefacts, since on every host/run that directory can be different.
Eliminate that and rely on shell commands to find the project root, executed within the genrule.
Reviewed By: jvillard
Differential Revision: D15963807
fbshipit-source-id: b6e590029
Summary:
Some functions exposed in ScubaLogging interface were not
used outside of ScubaLogging and caused deadcode to fail.
Reviewed By: ngorogiannis
Differential Revision: D15964204
fbshipit-source-id: d823dbf8b
Summary:
Reduces the size of the `tenv` by sharing values as most as possible, in an untyped - but supposedly safe - way, by using black magic on objects.
Can be reused for other things later.
Reviewed By: ngorogiannis
Differential Revision: D15855870
fbshipit-source-id: 169a4b86b
Summary:
Using `Marshal.to_string` to create SQLite values used in comparisons is brittle as there is no guarantee that it will return the same value for structurally equal values.
When adding sharing, this will definitely break.
From the SQLite queries I found, only `SourceFile` and `Procname` are used in comparisons.
I haven't tested performance.
It shouldn't change anything for `SourceFile` as there is no possible sharing.
It shouldn't change much for `Procname` as they are pretty small anyway.
Reviewed By: ngorogiannis
Differential Revision: D15923122
fbshipit-source-id: ce4af1fe3
Summary: Inject destructor calls to destroy a temporary when its lifetime ends.
Reviewed By: mbouaziz
Differential Revision: D15674209
fbshipit-source-id: 0f783a906
Summary:
Now that HIL doesn't help us anymore we need to reconstruct its mapping
"SIL logical var -> program access path". We already have everything we
need in pulse: it suffices to walk the current memory graph starting
from program variables until we find the value of the temporary we are
interested in.
This diff also builds some type machinery to make sure all accesses are
explained.
Reviewed By: mbouaziz
Differential Revision: D15824959
fbshipit-source-id: 722c81b39
Summary:
It turns out HIL gets in the way of a precise heap analysis. For
instance, instead of:
```
n$0 = *&x.f
_ = delete(&x)
*&y = n$0
```
HIL tries hard to forget about intermediate variables and shows instead
```
_ = delete(&x)
*&y = *&x.f
```
Oops, that's a use-after-delete, whereas the original code was safe.
While it's easy to write SIL programs that are completely unsound for
HIL, they are not generated very often from the frontends. In fact, the
problem became apparent only when making the clang frontend translate
C++ temporaries destructors, which produces the situation above
routinely.
This diff makes the minimal amount of change to make Pulse build and
produce equivalent results (minus HIL bugs) starting from SIL instead of
HIL. The reporting sucks for now because we need to translate SIL
temporaries back into program access paths. This is done in the next
diff.
Reviewed By: mbouaziz
Differential Revision: D15824961
fbshipit-source-id: 8e4e2a3ed
Summary:
Just moving code around.
This is needed later to make some types in `PulseTrace` depend on
a new that I'll have to define in `PulseDomain`.
Also, this gives better names all around I think
Reviewed By: mbouaziz
Differential Revision: D15881281
fbshipit-source-id: e86c1472e
Summary:
Just moving code around.
This is needed later to make some types in `PulseInvalidation` depend on
a new type that I'll have to define in `PulseDomain`.
Reviewed By: mbouaziz
Differential Revision: D15824962
fbshipit-source-id: 86cba2bfb
Summary:
Make it possible to re-use the graph visitor to compute all sorts of
things with a flexible API where you can pass a function that folds over
all addresses reachable from certain stack variables (specified with a
filter) and gets passed the access path that leads to each address.
This is used in later commits.
Reviewed By: mbouaziz
Differential Revision: D15824960
fbshipit-source-id: c424a71cb
Summary: Preanalysis is performed at the frontend now. Hence, we don't need to repeatedly check/set when/if it is performed.
Reviewed By: mbouaziz
Differential Revision: D15863175
fbshipit-source-id: f9c6b7ae1
Summary:
One "interesting" feature of the approach of merging the captured targets in Java, is that we union their type environments, as opposed to store partial tenvs together with each source file, which is the case for Clang.
This means
- the final global type environment is potentially huge because it contains all the types in all targets.
- all analysis workers start by loading that tenv in memory, meaning we consume `|size of tenv| x #cpus` memory, which can tip the balance towards OOMs
This diff attempts to economise on global tenv size. This is done by increasing sharing which is then preserved by marshalling. It's done in a brute force way, with hashtables for each struct component, and is not fully effective due to the recursion amongst types and types names, as well types appearing inside other constructs such as procnames.
This is done when calling `Tenv.store` so that
- the computation can be parallelised somewhat (capture is parallel, merging is not)
- buck caching will benefit from smaller tenvs.
This saves about 24% of total memory devoted to the type environment.
Reviewed By: mbouaziz
Differential Revision: D15840054
fbshipit-source-id: 6f03be1a4
Summary:
- Add allocation costs to `costs-report.json` and enable diffing over allocation costs.
- Also, let's be more consistent and modular in naming our cost issues.
- introduce a generic issue type `X_TIME_COMPLEXITY_INCREASE` where `X` can be one of the cost kinds. If the function is on the cold start, issue can have the `COLD_START` suffix. Similarly for infinite/zero/expensive calls.
- Change `PERFORMANCE_VARIATION` -> `EXECUTION_TIME_COMPLEXITY_INCREASE`
- Add new issue type for `ALLOCATION_COMPLEXITY_INCREASE_COLD_START` which will be enabled by default
- Refactor cost issues to be more modular and succinct. This also makes addition of a new cost kind very easy by adding the kind into the `enabled_cost_kinds` list in `CostKind.ml`
Reviewed By: mbouaziz
Differential Revision: D15822681
fbshipit-source-id: cf89ece59
Summary:
This one isn't caught because we don't destruct temporaries that are
bound to a const reference. According to the C++ standard these should
get destroyed when the const reference gets destroyed but instead we
just don't destroy them for now.
Reviewed By: mbouaziz
Differential Revision: D15760209
fbshipit-source-id: 32c935ec0
Summary:
In a next diff temporaries will get destructed at the end of their
lifetimes and that naive model would be causing false positives.
The flipside is that we lose all reports on closures for now, will need
to model them separately later.
Reviewed By: mbouaziz
Differential Revision: D15695943
fbshipit-source-id: c2c482c02
Summary:
Needed for next diff: we'll need to do 2 passes on the AST to collect
the temporaries to destroy at the end of an `ExprWithCleanups`, but the
SIL names of these temporaries are generated freshly on the fly so they
would get different names if we do it naively.
This adds a hashmap to the translation context so the temporary
corresponding to a given `MaterializeTemporyExpr` is only generated once
and then reused.
Reviewed By: mbouaziz
Differential Revision: D15674212
fbshipit-source-id: 0e16062d9
Summary:
This started as an attempt to understand how to modify the frontend to
inject destructors for C++ temporaries (see next diffs).
This diff rewrites the existing logic for computing the list of
variables that should be destroyed at the end of each statement, either
because it's the end of their syntactic scope or because control flow
branches outside of their syntactic scope.
The frontend translates a function from the last instructions to the
first, but scope computation needs to be done in the other direction, so
it's done in a separate pass *before* the main translation happens. That
first pass creates a map from statements in the AST to the list of
variables that should be destroyed at the end of these statements. This
is still the case now.
Before, that map would be computed in a bit of a weird way: scopes are
naturally a stack but instead of that the structure maintained was a
flat list + a counter to know where the current scope ended in that
list.
In this diff, redo the computation maintaining a stack of scopes
instead, which is a bit cleaner. Also treat more instructions as
introducing a new scope, eg if, for, ...
Reviewed By: mbouaziz
Differential Revision: D15674208
fbshipit-source-id: c92429e82
Jules Villard
Mehdi Bouaziz
Phoebe Nichols
Radu Grigore
Nikos Gorogiannis
Artem Pianykh
Dino Distefano
Ezgi Çiçek