Summary:
Before: the trace would explain how a value was invalidated and
accessed, but not how the value that was invalidated had been
constructed.
Now: `PulseTrace.t` records breadcrumbs of how the value was constructed
in addition to the interproc "action" trace leading to the invalidation
or access action.
Concretely:
```
void bad(X &x) {
X *y = x;
X *z = x;
delete y;
access(z);
}
```
will produce the trace:
Invalidation part:
y = x
delete y
Access part:
z = x
access(z)
access to z->f inside of access(z)
Before this diff the "Access part" would be missing the "z = x" part of
the trace, so it might be confusing why `z` has anything to do with `y`.
However, such "breadcrumbs" are not recorded in the inter-procedural
part, only the sequence of calls is. This is a trade-off for simplicity,
maybe it's enough for developers maybe it isn't, we'll find out later.
Reviewed By: jberdine
Differential Revision: D15354438
fbshipit-source-id: 8d0aed717
Summary:
update-submodule: facebook-clang-plugins
We used to translate `offsetof` by an unknown value.
This fixes it. It is now translated like an integer literal.
Reviewed By: ddino
Differential Revision: D15317799
fbshipit-source-id: ae89e0ec5
Summary:
Feedback from peterogithub:
- mention which access path is being invalidated and accessed in the message
- mention the line at which it was invalidated (the line at which it's accessed is already the line at which we report)
- traces for stack variable/C++ temporary address escapes
- delete double implementation of the same functionality in
`PulseTrace`: `location_of_action_start` is the same as
`outer_location_of_action`...
Reviewed By: jberdine
Differential Revision: D14800294
fbshipit-source-id: 3d9ab9b3d
Summary:
Similarly to function parameters (and the return value), we need to
apply the pre/post of a function call to the globals mentioned in its
summary.
- tigthen summaries further to remember only abducible variables in the
post (as well as in the pre)
- take globals into account when applying pre/post pairs
Reviewed By: jberdine
Differential Revision: D14780800
fbshipit-source-id: fc0d180bb
Summary:
The heuristic to detect variables going out of scope was to detect any
access expression passed as argument to an injected destructor call.
However destructor calls are also injected in destructor bodies to
destruct each field of an object, so the heuristic would detect fields
going out of scope, which, erm, doesn't make sense. Limit the heuristic
to local program variables.
Reviewed By: jberdine
Differential Revision: D14771454
fbshipit-source-id: ffa3c9fe3
Summary:
Only throw values to the pre if they can be followed from "abducible"
variables: formals of the current method and globals.
Because figuring out if a `Pvar.t` is a formal of the current procedure
is actually a giant pain, hack something not too bad instead:
pre-register all formals at the start of the analysis of the
procedure. Then the only other variables we care about in the
precondition are globals, which we can detect easily.
This is mostly an optimisation (summaries won't include irrelevant
"abduced" facts about the procedure's local variables anymore), but it
also fixes a bug where we would sometimes overwrite things in the pre. I
think that's why the tests improved.
Reviewed By: ngorogiannis
Differential Revision: D14753493
fbshipit-source-id: 08e73637f
Summary:
This mostly doesn't make sense. The only thing this would have been good
for was to give the most accurate result on access paths such as
`*(&(x.f))`, but these are normalised anyway (into `x.f`) so we actually
never see these. That said there might be some use to some similar logic
in the future, but in the meantime let's delete the current feature as
it wasn't thought through.
Reviewed By: ezgicicek
Differential Revision: D14753492
fbshipit-source-id: 597cec027
Summary:
The previous message formatting had regressed and produced non-sensical messages.
More importantly, remove template parameters from error messages to
trigger the heuristic in `InferPrint` that deduplicates errors that are
on the same line with the same error type and message. Without this we
get hundreds of reports that correspond to as many instantiations of the
same code.
Reviewed By: ngorogiannis
Differential Revision: D14747979
fbshipit-source-id: 3c4aad2b1
Summary:
We see the magic function `__variable_initialization` at the point where
the variable is declared, eg `int x = foo()`. It's safe to reset `&x` at
that point. This circumvents an issue that pops up in some rare cases
where the ternary conditional operator `?:` and variable initialization
conspire to produce weird frontend results.
Some test becomes a FN again, but I think it was being reported for the
wrong reasons; will investigate more later.
Reviewed By: ngorogiannis
Differential Revision: D14747980
fbshipit-source-id: e75d6e30f
Summary:
This ensures that each attribute type can only be present once per
address. Makes ~80x time improvement on pathological cases such as
Duff's device.
This introduces a new kind of Set in `PrettyPrintable`.
Reviewed By: mbouaziz
Differential Revision: D14645091
fbshipit-source-id: c7f9b760c
Summary:
Detect when a variable goes out of scope. When that's the case, mark its
address *and* its contents as invalid.
Give subsequent uses a USE_AFTER_LIFETIME error type instead of
USE_AFTER_DESTRUCTOR.
Reviewed By: jberdine
Differential Revision: D14387147
fbshipit-source-id: a2c530fda
Summary:
Increases precision a bit. I didn't observe speed problems on what I tested. (But, who knows?)
Closes https://github.com/facebook/infer/pull/799
Reviewed By: jvillard
Differential Revision: D6284206
Pulled By: rgrig
fbshipit-source-id: 6f1e8631f
Summary:
Instead of emitting an ad-hoc builtin on variable declaration emit a new
metadata instruction. This allows us to remove the code matching on that
ad-hoc builtin that had to be inserted in several checkers.
Inferbo & pulse used that information meaningfully and had to undergo
some minor changes to cope with the new metada instruction.
Reviewed By: ezgicicek
Differential Revision: D14833100
fbshipit-source-id: 9b3009d22
Summary:
Bundle all non-semantic-bearing instructions into a `Metadata _`
instruction in SIL.
- On a documentation level this makes clearer the distinction between
instructions that encode the semantics of the program and those that are
just hints for the various backend analysis.
- This makes it easier to add more of these auxiliary instructions in
the future. For example, the next diff introduces a new `Skip` auxiliary
instruction to replace the hacky `ExitScope([], Location.dummy)`.
- It also makes it easier to surface all current and future such
auxiliary instructions to HIL as the datatype for these syntactic hints
can be shared between SIL and HIL. This diff brings `Nullify` and
`Abstract` to HIL for free.
Reviewed By: ngorogiannis
Differential Revision: D14827674
fbshipit-source-id: f68fe2110
Summary:
This diff propagates LatestPrune on function calls.
Depends on D14321605
Reviewed By: mbouaziz
Differential Revision: D14321618
fbshipit-source-id: cb2e1b547
Summary:
Given a pointer-typed parameter, Inferbo assumes that it is an array
block. However, when a pointer is given as an actual parameter, it
failed the substitution of the array block value of the parameter, thus
which made some return values to bottom unexpectedly.
This diff revises the substitution of array block, so it can
substitute array block values with actual pointers correctly when it
is possible.
Reviewed By: mbouaziz
Differential Revision: D14663475
fbshipit-source-id: 0477de1ba
Summary:
This diff accumulates LatestPrune in sequential prunings. It should be sound since Inferbo invalidates some data of LatestPrune if they are updated.
Depends on D14321534
Reviewed By: mbouaziz
Differential Revision: D14321575
fbshipit-source-id: 233dbae32
Summary:
Some of these tests were wrong, eg `~lambda()` calls `lambda()` then...
takes the bitwise complement or something? The intent was to call the
destructor.
Add interprocedural tests for later.
Reviewed By: jberdine
Differential Revision: D14324762
fbshipit-source-id: 40d2c32f5
Summary:
Previously we would say that `lhs <= rhs` (or `lhs |- rhs`) when a
mapping existed between the abstract addresses of `lhs` and `rhs` such
that `mapping(lhs)` was a supergraph of `rhs`. In particular,
we had that `x |-> x' * x' |-> x'' |- x |-> x'`. This is not entirely
great, in particular once we get pairs of state representing footprint +
current state. I'm not sure I have an extremely compelling argument why
though, except that it's not the usual way we do implication in SL, but
there wasn't a compelling argument for the previous state of affairs
either.
This changes `|-` to be true only when `mapping(lhs) = rhs` (modulo only
considering the addresses reachable from the stack variables).
Reviewed By: jberdine
Differential Revision: D14568272
fbshipit-source-id: 1bb83950e
Summary: This helps convergence when `<=` is based on physical equality for example, and widening is implemented as `widen ~prev ~next = join prev next`.
Reviewed By: skcho
Differential Revision: D14568270
fbshipit-source-id: ded5ed296
Summary:
Re-declarations of global variables sometimes hide constant
initializations in the original declaration, which caused FN before.
In this diff, it translates global variables to point to original
declarations, rather than following re-declarations, if possible.
Reviewed By: mbouaziz, jvillard
Differential Revision: D14596301
fbshipit-source-id: 55c3b5f95
Summary: In SIL, sometimes a return value is assigned to `__return_param`.
Reviewed By: ezgicicek, mbouaziz
Differential Revision: D14538590
fbshipit-source-id: dfbb74dc2
Summary: This diff substitutes symbolic values for unknown functions in proof obligations to top. The goal of the diff is to avoid generating too many number of proof obligations that cannot be concretized.
Reviewed By: ezgicicek
Differential Revision: D14537542
fbshipit-source-id: 7f8f3bb4b
Summary:
TOPL properties are essentially automata, which specify a bad pattern.
This commit is just a parser for them.
Reviewed By: jvillard
Differential Revision: D14477671
fbshipit-source-id: c38a8ef37
Summary:
Add support for GuardedBy: we deviate from the spec as follows:
- No warnings issued for any access within a private method, unless that method is called from a public method and the lock isn't held when the access occurs.
- Warnings are suppressed with the general RacerD mechanism, ie `ThreadSafe(enableChecks=false)`
- GuardedBy warnings override thread-safety violation warnings on the same access, because GuardedBy has a clearer and simpler contract.
Also, some simplifications, cleanups and perf improvements (eg avoid unreportable procs at the top level as opposed to on each of their accesses).
Reviewed By: jeremydubreil
Differential Revision: D14506161
fbshipit-source-id: b7d794051
Summary:
While adding a footprint frame during rearrangement, the footprint
variables should be fresh with respect to the current state too, not
only with respect to he footprint, because the frame is added to the
state.
Reviewed By: jberdine
Differential Revision: D14401026
fbshipit-source-id: 20ea4485a
Summary:
To meet the pure parts of formulas, the process was to (a) call Rename.extend
with variables occuring in similar places and (b) extract substitutions out of
those. Two matching primed vars would both be replaced by some fresh primed var.
However, equivalence classes of primed variables would *not* be replaced by
one fresh (primed) variable. Now, that should work.
Reviewed By: mbouaziz
Differential Revision: D14150192
fbshipit-source-id: 90ca9216c
Summary:
This will be used in the future to determine what to do with destructors
in pulse.
Reviewed By: mbouaziz
Differential Revision: D14324759
fbshipit-source-id: bc3c34471
Summary:
This seems generally useful. Force people to do it in the future even if
they want to avoid having to update the frontend tests.
Reviewed By: mbouaziz
Differential Revision: D14324758
fbshipit-source-id: cdef3f72a
Summary:
When joining two lists of disjuncts we try to ensure there isn't a state
that under-approximates another already in the list. This helps reduce
the number of disjuncts that are generated by conditionals and loops.
Before we would always just add more disjuncts unless they were
physically equal but now we do a subgraph computation to assess
under-approximation.
We only do this half-heartedly for now however, only taking into
consideration the "new" disjuncts vs the "old" ones. It probably makes
sense to do a full quadratic search to minimise the number of disjuncts
from time to time but this isn't done here.
Reviewed By: mbouaziz
Differential Revision: D14258482
fbshipit-source-id: c2dad4889
Summary: Unknown locations in the alias domain resulted in unexpected unreachable code.
Reviewed By: mbouaziz
Differential Revision: D14339412
fbshipit-source-id: a5dca6489
Summary:
The disjunctive domain shouldn't really be a set in the first place as
comparing abstract states for equality is expensive to do naively
(walking the whole maps representing the abstract heap). Moreover in
practice these sets have a small max size (currently 50 for pulse, the
only client), so switching them to plain lists makes sense.
Reviewed By: mbouaziz
Differential Revision: D14258489
fbshipit-source-id: c512169eb
Summary:
It's useful to keep the size of states down, especially when humans are
trying to read it. It will also help keep the size of summaries down in
the inter-procedural pulse.
Reviewed By: mbouaziz
Differential Revision: D14258486
fbshipit-source-id: 45ebcac67
Summary: After a redeclaration of a global constant, it is not parsed as ICE(integral constant expression), which results in FN.
Reviewed By: ezgicicek
Differential Revision: D14299288
fbshipit-source-id: 394afd595
Summary:
It assigns symbolic values for global variables in the load commands. However, it does not instantiate the symbols for the global variables yet, which will be addressed in another diff.
Depends on D14208643
Reviewed By: ezgicicek
Differential Revision: D14257619
fbshipit-source-id: f9113c8a3
Summary:
the predicate to check that a decl is const was not working for VarDecl.
This diff fixes this
Reviewed By: jvillard
Differential Revision: D14106798
fbshipit-source-id: 1f6c24113
Summary:
This diff differentiates proof obligations by allocsites. Sizes and
offsets of arrays were joined when making proof obligations.
Reviewed By: mbouaziz
Differential Revision: D14163149
fbshipit-source-id: cb6608c16
Summary:
The Eradicate backend is reporting nullable type errors, that are not always necessarily leading to null pointer exceptions.
For example, the analysis is designed to be consistent with the Java type system and report on the following code:
String foo(boolean test) {
Object object = test ? new Object() : null;
if (test) {
return object.toString(); // the analysis reports here
}
}
even though the code will not crash.
In order to make this aspect clear, this diff renames the warnings `Null Method Call` and `Null Field Access` into `Nullable Dereference`
Reviewed By: ngorogiannis
Differential Revision: D14001979
fbshipit-source-id: ff1285283
Summary:
This diff adds a constant to the set of widening thresholds if the
constant is compared to an abstract value in condition expressions.
Each abstract value has its own set of thresholds.
Reviewed By: mbouaziz
Differential Revision: D14147150
fbshipit-source-id: ca0db34d4
Summary:
In this diff, it avoids a precision-losing pruning, which was needed
to keep effects of assume commands.
```
unsigned int c = a + b; // (1)
if (c > 0) { // (2)
char result[c];
result[c - 1] = 0; // (4)
}
```
For example, in the example, `c` is assigned by `[a+b,a+b]` at (1),
then it tried to prune the lower bound of `c` to 1 at (2) while losing
precision, in order to say `c - 1` at (4) is safe in terms of integer
underflow. Instead, it could not say that `c - 1` is smaller than `c`
in the buffer access, because the former is analyzed to `[0,a+b-1]` and
the latter `[1,a+b]` at (4).
Now, the situation has changed. By adopting conditional proof
obligation (D13749914), the FP of integer overflow can be suppressed
without the precision-losing pruning.
Reviewed By: mbouaziz
Differential Revision: D14122770
fbshipit-source-id: 634744e99
Summary: Since Inferbo's current min/max domain can keep only a single symbol, e.g. min(constant, symbol) , it loses precision when trying to prune a value including multiple symbols.
Reviewed By: ezgicicek
Differential Revision: D14099399
fbshipit-source-id: 71d677b75
Summary: Record where each symbol in a polynomial is coming from: either a loop, function call or a modeled call.
Reviewed By: mbouaziz
Differential Revision: D14047420
fbshipit-source-id: 56d0bd926
Summary: It keeps alias of simple plus/minus arithmetic in order to pruning the value of "++i" expression.
Reviewed By: mbouaziz
Differential Revision: D14080230
fbshipit-source-id: d3af32a32
Summary: In SIL, Java's array member is a pointer to an array, while C++'s is the array itself. This diff differentiate them in evaluating abstract locations.
Reviewed By: ezgicicek, mbouaziz
Differential Revision: D14021451
fbshipit-source-id: 00f14fe3b
Summary:
- There is no need to use AI to compute a dot product: let's just fold over all nodes, but still do it in order (using the WTO) to report at the right place
- The previous version was computing a dot product on nodes for each node, which was quadratic, the new version is linear
- Report only once, the first time the threshold is reached (if in a loop, report at the loop head)
Reviewed By: ddino
Differential Revision: D14028171
fbshipit-source-id: b4a840c6e
Summary:
Add an option to specify some classes that we really want to warn about
with the liveness checker, even when they appear used because of the
implicit destructor call inserted by the compiler.
Reviewed By: mbouaziz
Differential Revision: D13991129
fbshipit-source-id: 7fafdba84
Summary:
Get rid of false positive as in the test by modelling `Double`. Longer term we
should probably prevent biabduction from blocking the angelic analysis on
`Nullable` fields but that seems harder.
Reviewed By: jeremydubreil
Differential Revision: D14005228
fbshipit-source-id: 59ef2ed66
Summary:
The purpose these serve is unclear to me. From the comment I *think*
they were used to hint to the biabduction backend that smart pointers
are just pointers. That said, The tests still mostly pass even without
that (just a few `weak_ptr` tests changed from `NULL_DEREFERENCE` to
`Bad_footprint`).
Moreover, this extra dereference was added unreliably. For instance,
this piece of code:
```
auto x = std::make_unique<X>(some_X);
```
would either get the extra dereference or not depending on which headers
were picked for the C++ stdlib.
The extra dereference was tripping up the liveness checker (see later in
the stack), and probably most checkers too.
Reviewed By: mbouaziz
Differential Revision: D13991130
fbshipit-source-id: 462923595
Summary: When a `VarDecl` has the attribute `unused` then do not assign its initialisation result to the corresponding variable.
Reviewed By: ngorogiannis
Differential Revision: D13974497
fbshipit-source-id: 28029f995
Summary: The Makefile was missing that target and making `make test-replace` at the root of the repo fail.
Reviewed By: ngorogiannis
Differential Revision: D13990483
fbshipit-source-id: 805b5d2a9
Summary:
If the result of `fgets` is not-null, the length of `s` should be
bigger than or equal to 1.
Reviewed By: mbouaziz
Differential Revision: D13939994
fbshipit-source-id: 298fe33f4
Summary:
This diff updates the reachability conditions of proof obligations at every function calls.
Depends on D13781124
Reviewed By: mbouaziz
Differential Revision: D13781147
fbshipit-source-id: 3c8768bd9
Summary:
It adds a semantics for evaluation of abstract location of literal
string, which was missing.
Reviewed By: mbouaziz
Differential Revision: D13915265
fbshipit-source-id: 741df843b
Summary: We do not want to export unnecessary information from clang plugin, hence, the solution to this false positive would be to annotate with `__unused__` attribute.
Reviewed By: jvillard
Differential Revision: D13861333
fbshipit-source-id: 774009f37
Summary:
This will allow to get the numerical results for Cost, Hoisting, Purity without the Inferbo issues.
For now, I still forced Inferbo issues for Cost and Purity to avoid lots of changes in tests, that will go away soon.
Reviewed By: ezgicicek, skcho
Differential Revision: D13826741
fbshipit-source-id: 796d1a50d
Summary:
This diff extends the abstract domain to keep binary conditions on
prunings, so Inferbo can suppress more proof obligations (i.e., false
positives) that are known to be unreachable according to the binary
conditions.
Depends on D13729600
Reviewed By: mbouaziz
Differential Revision: D13749914
fbshipit-source-id: 314f048f1
Summary:
`memcpy` should copy the contents of the source to the destination.
Depends on D13634754
Reviewed By: ezgicicek, mbouaziz
Differential Revision: D13668414
fbshipit-source-id: cb0ff2010
Summary: It extends the abstract location for C string length, i.e., the first index of the null character in character array.
Reviewed By: mbouaziz
Differential Revision: D13634241
fbshipit-source-id: d2727d5f5
Summary: Publish solutions to the lab, and a Docker file and image to get started more quickly with infer hacking.
Reviewed By: mbouaziz
Differential Revision: D13648847
fbshipit-source-id: daf48ad03
Summary:
This diff prevents deduplications of issues when they have different
conditions to reach.
Reviewed By: mbouaziz
Differential Revision: D13596220
fbshipit-source-id: 95f802edb
Summary:
In ObjC there are no access modifiers. The strongest alternative is to put methods in the implementation but omit them from the interface declaration.
Put exported ObjC methods in their own field in the class structure and use that in RacerD to decide whether to report on the method.
Reviewed By: mbouaziz
Differential Revision: D13597504
fbshipit-source-id: c4a3d2705
Summary:
It suppresses intended integer overflows that generate hash values or random numbers. For judging that the intention of integer overflow, it applies a heuristics: checking if traces of issues include a whitelisted words, e.g., "rand" or "seed".
While we would be able to suppress all integer overflows of unsigned integers since they have defined behaviors, we don't want to miss unintended integer overflows, e.g., that on unsigned index value.
Depends on D13595958
Reviewed By: mbouaziz
Differential Revision: D13595967
fbshipit-source-id: 8d3aca5a7
Summary:
Record per-location traces. Actually, that doesn't quite make sense as a
location can be accessed in many ways, so associate a trace to each
*edge* in the memory graph. For instance, when doing `x->f = *y`, we
want to take the history of the `<val of y> --*--> ..` edge, add "assigned
at location blah" to it and store this extended history to the edge
`<val of x> --f--> ..`.
Use this machinery to print nicer traces in `infer explore` and better
error messages too (include the last assignment, like biabduction
messages).
Reviewed By: da319
Differential Revision: D13518668
fbshipit-source-id: 0a62fb55f
Summary:
This diff substitutes the conditions of proof obligations strictly, so that the condition of "p!=Null" becomes bottom
when callee's p is Null.
In the non-strict substitution (which is used by default), if p's location is not found it returns the unknown location.
On the other hand, in the strict substitution (which is used only in the substitution of condition of proof obligation),
it returns bottom location.
Depends on D13415366, D13414636
Reviewed By: mbouaziz, jvillard
Differential Revision: D13415377
fbshipit-source-id: 5ae1e888e
Summary: This diff unset powloc and arrayblk values of p when assume(p==Null).
Reviewed By: mbouaziz, jvillard
Differential Revision: D13415366
fbshipit-source-id: a491a957f
Summary:
For abstract values representing one concrete value, create only one symbol instead of two.
Still create two symbols (lb, ub) for abstract values representing multiple concrete values (like array cells).
As a consequence, comparisons of symbolic values are more precise (we can even prove equality). I expect to remove a bunch of FPs.
Another consequence is the disappearance of `.lb` and `.ub` in many reports.
Reviewed By: skcho
Differential Revision: D13072084
fbshipit-source-id: 9bc0b9881
Andrew Adams-Moran
Jules Villard
Jeremy Dubreil
Dino Distefano
Mehdi Bouaziz
Nikos Gorogiannis
Ezgi Çiçek
David Lively
Lee Howes
Radu Grigore
Sungkeun Cho
Radu Grigore
Wenzhe Lu
Boris Valkov
Nikos Gorogiannis
Daiva Naudziuniene
Fabio Milano