Summary:
We need to make sure a node is created to avoid instructions appearing
in the wrong order in the final CFG.
Reviewed By: da319
Differential Revision: D25784405
fbshipit-source-id: 3ef27d712
Summary:
This was left as a TODO before: where to place calls to destructors for
C++ temporaries that are only conditionally creating when evaluating an
expression. This can happen inside the branches of a conditional
operation `b?e:f` or in potentially-short-circuited conditions on the
righ-hand side of `&&` and `||` operators.
Following the compilation scheme of clang (observed by looking at the
generated LLVM bitcode), we instrument the program with "marker"
variables, so that for instance `X x = true?X():y;` becomes (following
the execution on the true branch):
```
marker1 = 0; // initialize all markers to 0
PRUNE(true) // entering true branch
X::X(&temporary); // create temporary...
marker1 = 1; // ...triggers setting its marker to 1
X::X(&x, &temporary); // finish expression
if (marker1) {
X::~X(&temporary); // conditionally destroy the temporary
}
```
In this diff, you'll find code for:
- associating markers to temporaries that need them
- code to initialize markers to 0 before full-expressions
- code to conditionally destroy temporaries based on the values of the
markers once the full-expression has finished evaluating
Reviewed By: da319
Differential Revision: D24954070
fbshipit-source-id: cf15df7f7
Summary:
Split the translation of return more aggressively between:
1. the instruction that has to happen before the translation of the sub-expr
2. the sub-expr
3. the instruction that has to happen after the sub-expr
This is needed for the next diff which creates potentially large CFGs in
(2).
Reviewed By: da319
Differential Revision: D24954071
fbshipit-source-id: a7e7e2527
Summary:
This is several inter-connected changes together to keep the tests
happy.
The ConditionalOperator `b?t:e` is translated by first creating a
placeholder variable to temporarily store the result of the evaluation
in each branch, then the real thing we want to assign to reads that
variable. But, there are situations where that changes the semantics of
the expression, namely when the value created is a struct on the stack
(eg, a C++ temporary). This is because in SIL we cannot assign the
*address* of a program variable, only its contents, so by the time we're
out of the conditional operator we cannot set the struct value
correctly anymore: we can only set its content, which we did, but that
results in a "shifted" struct value that is one dereference away from
where it should be.
So a batch of changes concern `conditionalOperator_trans`:
- instead of systematically creating a temporary for the conditional,
use the `trans_state.var_exp_typ` provided from above if available
when translating `ConditionalOperator`
- don't even set anything if that variable was already initialized by
merely translating the branch expression, eg when it's a constructor
- fix long-standing TODO to propagate these initialization facts
accurately for ConditionalOperator (used by `init_expr_trans` to also
figure out if it should insert a store to the variable being
initialised or not)
The rest of the changes adapt some relevant other constructs to deal
with conditionalOperator properly now that it can set the current
variable itself, instead of storing stuff inside a temp variable. This
change was a problem because some constructs, eg a variable declaration,
will insert nodes that set up the variable before calling its
initialization, and now the initialization happens *before* that setup,
in the translation of the inner conditional operator, which naturally
creates nodes above the current one.
- add a generic helper to force a sequential order between two
translation results, forcing node creation if necessary
- use that in `init_expr_trans` and `cxxNewExpr_trans`
- adjust many places where `var_exp_typ` was incorrectly not reset when translating sub-expressions
The sequentiality business creates more nodes when used, and the
conditionalOperator business uses fewer temporary variables, so the
frontend results change quite a bit.
Note that biabduction tests were invaluable in debugging this. There
could be other constructs to adjust similarly to cxxNewExpr that were
not covered by the tests though.
Added tests in pulse that exercises the previous bug.
Reviewed By: da319
Differential Revision: D24796282
fbshipit-source-id: 0790c8d17
Summary: Structs captured both by reference or by value should have reference in their type. Struct captured by value should first call copy constructor. In this diff we fix the type of the captured variable to include reference. Copy constructor injection is left for the future.
Reviewed By: jvillard
Differential Revision: D23688713
fbshipit-source-id: d13748b5d
Summary: Variables captured without initialization do not have correct type inside lambda's body. This diff sets the correct type of captured reference variables inside procdesc and makes sure the translation of captured variables is correct. The translation of lambda's body will then take into account the type of captured var from procdesc.
Reviewed By: jvillard
Differential Revision: D23678371
fbshipit-source-id: ed16dc978
Summary: Add missing reference to the type of variable captured by reference without initialization.
Reviewed By: jvillard
Differential Revision: D23567685
fbshipit-source-id: b4e2ac0b6
Summary:
We were missing assignment to captured variables with initializers.
Consider the following example:
```
S* update_inside_lambda_capture_and_init(S* s) {
S* object = nullptr;
auto f = [& o = object](S* s) { o = s; };
f(s);
return object;
}
```
which was translated to
```
VARIABLE_DECLARED(o:S*&);
*&o:S*&=&object
*&f =(_fun...lambda..._operator(),([by ref]&o &o:S*&))
```
However, we want to capture `o` (which is an address of `object`), rather `&o` in closure.
After the diff
```
VARIABLE_DECLARED(o:S*&);
*&o:S*&=&object
n$7=*&o:S*&
*&f =(_fun...lambda..._operator(),([by ref]n$7 &o:S*&))
```
Reviewed By: jvillard
Differential Revision: D23567346
fbshipit-source-id: 20f77acc2
Summary: Lambda is called using `operator()`. We need to know the information of captured variables when `operator()` procedure is being analysed. This diff records lambda captured variables in `operator()` procdesc. The complication arises from the fact that procdesc for `operator()` is created before translating lambda expression or during the translation of lambda expression where captured variables are translated. To solve this issue, we update existing `operator()` procdesc attributes with captured variable information when we translate lambda expression.
Reviewed By: jvillard
Differential Revision: D22374495
fbshipit-source-id: 44909adea
Summary:
We update the type of captured variables to include information about capture mode (`ByReference` or `ByValue`) both for procdesc attributes and the closure expression.
For lambda: closure expression now contains correct capture mode for capture variables. Procdesc still does not contain information about captured variables which we will address in the next diff.
For objc blocks: at the moment all captured variables have mode `ByReference`. Added TODOs to fix this.
Reviewed By: jvillard
Differential Revision: D22572054
fbshipit-source-id: 4c88678ee
Summary:
This also prints the CFGs *after* pre-analysis for individual procedures
in infer-out/captured/<filename>/<proc>.dot. One can also look up the
CFGs before pre-analysis in infer-out/captured/proc_cfgs_frontend.dot.
Context: I want to add a pre-analysis that needs to look at proc
attributes inter-procedurally. For this to make sense it has to happen
*after* all of capture, and before analysis.
Thus, this diff brings back the lazy running of the pre-analysis like in
D15803492, except that we still make sure to run the pre-analyses
systematically regardless of the checkers being run by running the
pre-analysis from ondemand.ml. Also we don't need to re-introduce the
"did_preanalysis" proc attribute for the same reason that the
pre-analysis is now run once and for all by ondemand.ml (instead of each
individual checker back in the days).
This has the benefit of running the pre-analysis only when needed, and
the drawback that several concurrent processes analysing the same proc
descs will duplicate work. Since pre-analyses are supposed to be very
fast I assume that neither is a big deal. If they become more expensive
then the benefit gets bigger and the drawback is just the same as with
regular analyses.
Reviewed By: skcho
Differential Revision: D18573920
fbshipit-source-id: de350eaef
Summary:
- more flexible API
- less error-prone thanks to named parameters
- also takes care of adjusting predecessors of the previous successors!
This fixes some (probably harmless) bugs in the frontends.
Reviewed By: dulmarod
Differential Revision: D18573923
fbshipit-source-id: ad97b3607
Summary: Inject destructor calls to destroy a temporary when its lifetime ends.
Reviewed By: mbouaziz
Differential Revision: D15674209
fbshipit-source-id: 0f783a906
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
Summary:
Somewhat trivial: add a string to "Destruction" nodes to indicate why
they were created. Rename the main `instruction_aux` function into
`instruction_translate` (see next diff for why).
Reviewed By: mbouaziz
Differential Revision: D15674211
fbshipit-source-id: 8a7eda72c
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:
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:
Before, the liveness pre-analysis would place extra instructions in the
CFG for either:
1. marking an `Ident.t` as dead, or
2. marking a `Pvar.t` as `= 0`
But we have no way of marking pvars dead without setting them to 0. This
is bad because setting pvars to 0 is not possible everywhere they are
dead. Indeed, we only do it when we haven't seen their address being
taken anyway. This prevents the following situation, recorded in our tests:
```
int address_taken() {
int** x;
int* y;
int i = 7;
y = &i;
x = &y;
// if we don't reason about taken addresses while adding nullify instructions,
// we'll add
// `nullify(y)` here and report a false NPE on the next line
return **x;
}
```
So we want to mark pvars as dead without nullifying them. This diff
extends the `Remove_temps` SIL instruction to accept pvars as well, and
so renames it to `ExitScope`.
Reviewed By: da319
Differential Revision: D13102953
fbshipit-source-id: aa7f03a52
Summary:
Useful to understand the changes in the pre-analysis, or to inspect the
CFG that checkers actually get.
This means that the pre-analysis always runs when we output the dotty,
but I don't really see a reason why not. In fact, we could probably
*always* store the CFGs as pre-analysed.
Reviewed By: mbouaziz
Differential Revision: D13102952
fbshipit-source-id: 89f3102ec
Summary:
Update clang plugin which now gives names to variables captured by lambdas that were empty before.
update-submodule: facebook-clang-plugins
Reviewed By: jvillard
Differential Revision: D12979015
fbshipit-source-id: 0b092fb24
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:
New clang in the plugin \o/
Changes that were needed:
- (minor) Some extra AST nodes
- defining a lambda and calling it in the same line (`[&x]() { x = 1; }()`) used to get translated as a call of the literal but now an intermediate variable gets created, which confuses uninit in one test. I added another test to showcase the limitation this is hitting: storing the lambda in a variable then calling it will not get caught by the checker.
The controller you requested could not be found.: facebook-clang-plugins
Reviewed By: jeremydubreil
Differential Revision: D10128626
fbshipit-source-id: 8ffd19f3c
Summary:
Change the license of the source code from BSD + PATENTS to MIT.
Change `checkCopyright` to reflect the new license and learn some new file
types.
Generated with:
```
git grep BSD | xargs -n 1 ./scripts/checkCopyright -i
```
Reviewed By: jeremydubreil, mbouaziz, jberdine
Differential Revision: D8071249
fbshipit-source-id: 97ca23a
Summary:
Previously, the type of `trans_result` contained a list of SIL expressions.
However, most of the time we expect to get exactly one, and getting a different
number is a soft(!) error, usually returning `-1`.
This splits `trans_result` into `control`, which contains the information
needed for temporary computation (hence when we don't necessarily know the
return value yet), and a new version of `trans_result` that includes `control`,
the previous `exps` list but replaced by a single `return` expression instead,
and a couple other values that made sense to move out of `control`. This allows
some flexibility in the frontend compared to enforcing exactly one return
expression always: if they are not known yet we stick to `control` instead (see
eg `compute_controls_to_parent`).
This creates more garbage temporary identifiers, however they do not show up in
the final cfg. Instead, we see that temporary IDs are now often not
consecutive...
The most painful complication is in the treatment of `DeclRefExpr`, which was
actually returning *two* expressions: the method name and the `this` object.
Now the method name is a separate (optional) field in `trans_result`.
Reviewed By: mbouaziz
Differential Revision: D7881088
fbshipit-source-id: 41ad3b5
Summary:
This simplifies the frontends and backends in most cases. Before this diff,
returning `void` could be modelled either with a `None` return, or a dummy
return variable with type `Tvoid`. Now it's always the latter.
Reviewed By: sblackshear, dulmarod
Differential Revision: D7832938
fbshipit-source-id: 0a403d1
Summary:
When looking at large CFGs, at least in `xdot`, it's often difficult to find
the procedure you're looking for. Sorting the proc names puts them in
alphabetical order, which makes searching one procedure easier.
Reviewed By: mbouaziz
Differential Revision: D7758521
fbshipit-source-id: 8e9997f
Summary: We do not inject a destructor call if the destructor declaration does not contain a body in AST. We miss all the cases where the destructor is declared in `.h` file and defined in `.cpp` file as other files include `.h` file and do not contain the body of the destructor when destructor calls are being injected based on AST information. After this diff we inject destructor calls even if we do not have body for the destructor in AST.
Reviewed By: sblackshear
Differential Revision: D6796567
fbshipit-source-id: 1c187ec
Summary: In Obj-C blocks, we explicitly insert reads of the captured vars. This does the same thing for C++. For example, `foo() { int x = 1; [x]() { return x; } }` would previously not contain a read of `x` in `foo`. Now, we'll create a temporary that reads from `x` and pass it to the closure value.
Reviewed By: dulmarod
Differential Revision: D6939997
fbshipit-source-id: f218afc
Summary:
Not sure what an "iCFG" is but the dotty is only about CFGs anyway.
Diff obtained by mass-`sed`.
Reviewed By: sblackshear
Differential Revision: D6324280
fbshipit-source-id: b7603bb
Summary:
The previous domain for SIOF was duplicating some work with the generic Trace
domain, and basically was a bit confused and confusing. A sink was a set of
global accesses, and a state contains a set of sinks. Then the checker has to
needlessly jump through hoops to normalize this set of sets of accesses into a
set of accesses.
The new domain has one sink = one access, as suggested by sblackshear. This simplifies
a few things, and makes the dedup logic much easier: just grab the first report
of the list of reports for a function.
We only report on the fake procedures generated to initialise a global, and the
filtering means that we keep only one report per global.
Reviewed By: sblackshear
Differential Revision: D5932138
fbshipit-source-id: acb7285
Summary:
With this change and the previous facebook-clang-plugins change, infer no
longer exhausts the biniou buffer when reading the serialized C++ AST.
update-submodule: facebook-clang-plugins
Reviewed By: mbouaziz
Differential Revision: D5891081
fbshipit-source-id: cf48eac
Summary:
Not translating these properly was causing false positives for the dead store analysis in cases like
```
int i = 0;
return [j = i]() { return j; }();
```
Reviewed By: da319
Differential Revision: D5731562
fbshipit-source-id: ae79ac8
Summary:
We were including hex of empty string if mangled name was not empty (so for all C++ functions).
Instead, include hex of a source file only if it's not empty
Reviewed By: mbouaziz
Differential Revision: D4705388
fbshipit-source-id: 55b6587
Summary:
Procnames files are now reversed qualifier lists with `#` as separator (instead of `::` which needs to be escaped in bash).
Because of the mechanism that is used to obtain qualifiers, it also affects naming for ObjC classes.
Examples:
```
std::unique_ptr<int>::get -> get#unique_ptr<int>#std#__MANGLED,...__ // C++ method
folly::split -> split#folly#__MANGLED,..._ // function within namespace
NSNumber numberWithBool: -> numberWithBool:#NSNumber#class // ObjC method
```
Reviewed By: jvillard
Differential Revision: D4689701
fbshipit-source-id: c3acfc6
Summary: Globals that are constexpr-initializable do not participate in SIOF.
Reviewed By: sblackshear
Differential Revision: D4277216
fbshipit-source-id: fd601c8
Summary:
Currently cfg nodes are written into dot files in whatever order they
appear in a hash table. This seems unnecessarily sensitive, so this
diff sorts the nodes.
Reviewed By: dulmarod
Differential Revision: D4232377
fbshipit-source-id: a907cc6
Summary: These are dangerous if you are trying to compare a type to a string, and they're also unsightly.
Reviewed By: jvillard
Differential Revision: D4189956
fbshipit-source-id: 14ce127
Jules Villard
Daiva Naudziuniene
David Lively
Mehdi Bouaziz
Dulma Churchill
Sam Blackshear
Andrzej Kotulski
Josh Berdine
Cristiano Calcagno