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: When a property was defined in a protocol, we were not translating its attributes which leads to retain cycles false positives. This diff fixes it. It also refactors the code for translating fields a bit.
Reviewed By: mbouaziz
Differential Revision: D7136355
fbshipit-source-id: b5e7445
Summary:
1) Fixes some false negatives when a method annotated with `nullable` in the header is not annotated in the implementation and the attribute lookup returns the implementation. In that case, we should follow the information given in the header.
2) Fixes some false positives when annotations are in the other way around, i.e. annotated in the implementation but not in the headers. For now, there should be no report in this case, but the analysis should be extended to report the inconsistency between the header and the implementation
3) Fixes some cases of weird reports caused by name conflicts where the method in the include has the same name has another method annotated differently.
Reviewed By: jvillard
Differential Revision: D6935379
fbshipit-source-id: 3577eb0
Summary:
- Combine two fields from ProcAttributes.t into a single field `method_kind` with more information
- New field details whether the procedure is an `OBJC_INSTANCE`, `CPP_INSTANCE`, `OBJ_CLASS`, `CPP_CLASS`, `BLOCK`, or `C_FUNCTION`
- `is_objc_instance_method` and `is_cpp_instance_method` fields no longer necessary
- Changed `is_instance` field in CMethod_signature to `method_kind` field of type ProcAttributes.method_kind
Reviewed By: dulmarod
Differential Revision: D6884402
fbshipit-source-id: 4b916c3
Summary:
The captured variables of a closure are tuples (id, var, typ) with the implicit assumption
that &var -> id holds in the heap. This is true when the closure is created, but is not enforce otherwise.
This becomes a problem when the closure is stored in the heap, goes passed a bi-abduction, and then it's executed
(see new test). This was failing before this diff and now succeeds.
We add the verification of this constraint to the normalization of sigma.
At the moment I expect Precondition_not_met to be removed, but also later, we will be able to compute retain cycles
over the closures, as the correct captured variable info is kept through the execution.
Reviewed By: jvillard
Differential Revision: D6796525
fbshipit-source-id: a8a7655
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:
Previously imports with relative filenames would not get resolved so the result
would depend on where infer had been run from. Usually this was the project
root. Now, resolve path names of imports relative to the file doing the
`#IMPORT`. This changes behaviour most of the time.
Reviewed By: dulmarod
Differential Revision: D6784740
fbshipit-source-id: 4ccb7bf
Summary:
This changes the syntax for AL imports from `#IMPORT <file>` to `#IMPORT
"file"`. As a side-effect, the `file` part is now lex'd more permissively too.
Reviewed By: dulmarod
Differential Revision: D6784669
fbshipit-source-id: cc1bb73
Summary:
Some commands (mostly `infer report`) would attempt to run the initialisation
code of infer from the default results directory instead of the one used by the
test. This is mostly harmless because we do not actually use anything from the
directory (typically, we pass `--from-json-results foo.json` and only foo.json
matters). However, this can trip the initialisation code, eg on db schema
changes.
Reviewed By: mbouaziz
Differential Revision: D6711641
fbshipit-source-id: f04b4c7
Summary: The checker should only propagate the nullablility on the lhs when of pointer type.
Reviewed By: sblackshear
Differential Revision: D6630294
fbshipit-source-id: 07fe3d6
Summary: This subdirectory was only containing tests related to nullable on Objective C.
Reviewed By: sblackshear
Differential Revision: D6657654
fbshipit-source-id: 11003f2
Summary:
Before this diff, the nullable checker would not be able to find annotations involving methods annotated in the protocols
update-submodule: facebook-clang-plugins
Reviewed By: sblackshear
Differential Revision: D6534893
fbshipit-source-id: 39bd3dd
Summary: Local `CKComponentScope`'s are often created purely for their side effects, so it's fine for them to be unread.
Reviewed By: jeremydubreil
Differential Revision: D6475475
fbshipit-source-id: 17e869a
Summary: This would allow the checker to detect indirect nullable violations, i.e. violations that are involving intermediate method calls on potentially `nil` values.
Reviewed By: sblackshear
Differential Revision: D6464900
fbshipit-source-id: 3663729
Summary: NSDictionary initialization will crash when using `nil` as a key or as a value
Reviewed By: dulmarod
Differential Revision: D6466349
fbshipit-source-id: 57bb012
Summary:
The diff is very big but it's mostly removing code. It was inspired by the fact that we were getting Dead Store FPs because we were modeling some functions from CoreFoundation and CoreGraphics directly as alloc in the frontend, which caused the parameters of the function to be seen as dead. See the new test.
To deal with this, if we are going to skip the function, we model it as malloc instead. Given how many models we had for those "model as malloc" functions, I removed them to rely solely on the new mechanism.
The modeling of malloc and release was still based on the old retain count implementation, even though all we do here is a malloc/free kind of analysis. I also changed
that to be actually malloc/free which removed many Assert false in the tests. CFRelease is not exactly free though, and it's possible to use the variable afterwards. So used a custom free builtin that only cares about removing the Memory attribute and focuses on minimizing Memory Leaks FPs.
Otherwise we were translating CFBridgingRelease as a special cast, and this wasn't working. To simplify this as well, I removed all the code for the special cast, and just modeled CFBridgingRelease and CFAutorelease also as free_cf, to avoid Memory Leak false positives. I also treated the cast __bridge_transfer as a free_cf model. This means we stopped trying to report Memory Leaks on those objects.
The modeling of CoreGraph release functions was done in the frontend, but seemed simpler to also simplify that code and model all the relevant functions.
Reviewed By: sblackshear
Differential Revision: D6397150
fbshipit-source-id: b1dc636
Summary: Adding a null key or a null value will cause a runtime exception.
Reviewed By: sblackshear
Differential Revision: D6378618
fbshipit-source-id: 8bd27c6
Summary:
This resolves#796 . Effectively it adds file specific suffix to name of all global initializers (so initializersof two global variable of the same name will have unique Typ.Procname). which is the same rule as currently used by constructing Procname for the static functions. However this change applies to initializers of all global variables and not just static (arguably it's a right thing. since GCC used to allow multiple global variables with the same name).
Consequences of this change that it becomes impossible to know name of generated initialization function of global ('extern') variables. However get_initializer_pname function is only referenced by the frontend (when creating initializer for the defined global variables) and by the SIOF checker.
Closes https://github.com/facebook/infer/pull/801
Reviewed By: jvillard
Differential Revision: D6335034
Pulled By: dulmarod
fbshipit-source-id: 1a92c08
Summary: Adding a nil object to an NSArray will crash. Adding this case to the checker.
Reviewed By: sblackshear
Differential Revision: D6346241
fbshipit-source-id: 3fe6f20
Summary: The clang compiler introduces a materialized temporary expression which should be treated similarly to the Infer internal temporary variables.
Reviewed By: sblackshear
Differential Revision: D6331237
fbshipit-source-id: 81d8196
Summary: This is a hack to removes most of the false positives of this checker in Objective C.
Reviewed By: sblackshear
Differential Revision: D6239914
fbshipit-source-id: 1cf05de
Summary: This check is deprecated and will be replaced by a dedicated checker to detect unitialized values.
Reviewed By: mbouaziz
Differential Revision: D6133108
fbshipit-source-id: 1c0e9ac
Summary:
1. Mark some Makefile targets as depending on `MAKEFILE_LIST` so they get rebuilt on Makefile changes
2. Do not show boolean options with no documentation in the man pages (like we do for other option types).
3. Default to Lazy dynamic dispatch for the checkers.
4. In the tests, use `--<checker>-only` instead of relying on `--no-default-checkers`
5. `--no-filtering` is redundant if `--debug-exceptions` is passed
Reviewed By: jeremydubreil
Differential Revision: D6030578
fbshipit-source-id: 3320f0a
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: The case of closures was not considered for the convertion of SIL instructions into HIL instructions
Reviewed By: sblackshear
Differential Revision: D5929675
fbshipit-source-id: bb6920a
Summary: Example of combination between annotating fields with nullable and the biabduction analysis in Objective C
Reviewed By: dulmarod
Differential Revision: D5906016
fbshipit-source-id: b95c6e0
Summary:
We take it into account to not report bugs inside the available block. This requires a plugin change.
update-submodule: facebook-clang-plugins
Reviewed By: jvillard
Differential Revision: D5891511
fbshipit-source-id: 21a02ad
Summary: The prune nodes where translated as `prune (expr = false)` and `prune ( expr != false)`. This case is a bit tricky to deconstruct in HIL. This diff translates the prune instructions as just `prune !expr` for the true branch and `prune expr` for the false branch.
Reviewed By: dulmarod
Differential Revision: D5832147
fbshipit-source-id: 2c3502d
Summary: Atoms of the form `identifier = footprint var` naturally occurs with the angelic analysis mode. So it is not clear to me why we should drop those.
Reviewed By: sblackshear
Differential Revision: D5654754
fbshipit-source-id: 9dd2eb5
Summary:
This is a check for when an unavailable class is being allocated.
This diff also adds a check for the context to remove false positives: If the class is not available but the method calls are wrapped in a check whether the class is available, then don't report.
Reviewed By: jvillard
Differential Revision: D5631191
fbshipit-source-id: 2082dfe
Summary:
Previous version was hard to understand because it was doing many things within same code. New version has different code for Arrays, Structs and others.
There is some copy-paste, but it's easier to follow code (open to suggestions though)
Reviewed By: dulmarod
Differential Revision: D5547999
fbshipit-source-id: 77ecb24
Summary: Those are not particularly relevant for the biabduction analysis. It would be easy to have a dedicated checker for this if we happen to need one day.
Reviewed By: sblackshear
Differential Revision: D5530834
fbshipit-source-id: 316e60f
Summary:
Bumps facebook-clang-plugins to a version that outputs sizeof() info in bytes and not bits.
update-submodule: facebook-clang-plugins
Reviewed By: akotulski
Differential Revision: D5526747
fbshipit-source-id: 6019542
Summary: The `--failures-allowed` was doing for the Clang frontend what `--keep-doing` was doing for the backend. This revision merges the two options to simplify the Infer CLI and our tests.
Reviewed By: jvillard
Differential Revision: D5474347
fbshipit-source-id: 09bcea4
Summary: Using a dedicated abstract domain, like Quandary does, is more suitable for taint analysis.
Reviewed By: sblackshear
Differential Revision: D5473794
fbshipit-source-id: c917417
Summary:
Both `stringWithUTF8String` and `stringWithString` implements copy semantics that copies the content of their parameter into a newly allocated buffer. We modeled this as pointer assignment in the past, which means that once we write
```
NSString* foo() {
char buf[...];
...
return [NSString stringWithUTF8String:buf];
}
```
We are going to get a spurious stack variable address escape report because local pointer `buf` is assigned to the newly created string and the string gets returned.
This diff tries to address the issue by heap-allocating a buffer and `memcpy` the contents in `stringWithUTF8String` and `stringWithString`. But this change will create another problem: the allocated buffer will be reported as leaked by the backend, while in reality those buffers won't actually be leaked as they are allocated in a region that will be periodically autoreleased. To suppress spurious memory leak FPs, I added another attribute `Awont_leak` that will suppress the leakage report on any expressions that get tagged with it.
Reviewed By: jeremydubreil
Differential Revision: D5403084
fbshipit-source-id: df6de7f
Summary: CFG nodes were not connected and some instructions ended up in wrong place. Fix those issues
Reviewed By: dulmarod
Differential Revision: D5406720
fbshipit-source-id: 2a70e1a
Summary:
This diff tries to achieve the followings: if we have the following C++ codes:
```
bool foo(int x, int y) {
return &x == &y;
}
```
We want the C++ frontend to emit Sil as if the input is written as
```
bool foo(int x, int y) {
if (&x == &y) return 1; else return 0;
}
```
This matches the behavior of our Java frontend.
The reason why we prefer an explicit branch is that it will force the backend to eagerly produce two different specs for `foo`. Without the explicit branch, for the above example the backend would produce one spec with `return = (&x == &y)` as the post condition, which is not ideal because (1) we don't want local variables to escape to the function summary, and (2) with the knowledge that no two local variables may alias each other, the backend could actually determines that `&x == &y` is always false, emitting a more precise postcondition `return = 0`. This is not possible if we do not eagerly resolve the comparison expression.
Reviewed By: akotulski
Differential Revision: D5260745
fbshipit-source-id: 6bbbf99
Summary:
An array has a static or dynamic length (number of elements), but it also has a
stride, determined by the type of the element: `sizeof(element_type)`. We don't
have a good `sizeof()` function available on SIL types, so record that stride
in the array type.
update-submodule: facebook-clang-plugins
Reviewed By: mbouaziz
Differential Revision: D4969697
fbshipit-source-id: 98e0670
Summary:
Introduce `infer-<command>` for each command, except for internal commands
(only `infer-clang` for now) which are not exported. Install these executables
(which are just symlinks to `infer`) on `make install`. The main executable
looks at the name it was invoked with to figure out if it should behave as a
particular command.
Get rid of `InferClang`, `InferAnalyze`, and `InferPrint`. As a bonus, we now
only need to build one executable: `infer`, which should be a few seconds
faster (less link time).
`InferAnalyze` is now `infer-analyze` and `InferPrint` is `infer-print`. To run
`InferClang`, use a symlink named `clang`, `clang++`, etc. to `infer`. There
are such symlinks available in "infer/lib/wrappers/" already.
I also noticed that the scripts in xcodebuild_wrappers/ don't seem useful
anymore, so use wrappers/ instead, as for `make`.
Reviewed By: mbouaziz
Differential Revision: D5036495
fbshipit-source-id: 4a90030
Summary:
Title.
The way types are printed is completely valid, but little weird for some C++ programmers:
`int const` - same as `const int`
`int * const` - pointer is `const`, value under it is not
`int const *` - pointer is not `const`, but the value is
`int const * const` - both pointer and value are const
Reviewed By: jberdine
Differential Revision: D4962180
fbshipit-source-id: dcb02e3
Summary:
Modify the type of `Exp.Sizeof ...` to include the value that the expression
evaluates to according to the compiler, or None if it cannot be known
statically.
Use this information in inferbo.
Mostly unused in the BiAbduction checker for now, although it could be useful
there too.
update-submodule: facebook-clang-plugins
Reviewed By: mbouaziz
Differential Revision: D4953634
fbshipit-source-id: be0999d
Summary:
Adds a new type and branching for a missing path of execution.
closes#575
Reviewed By: jvillard
Differential Revision: D4738681
fbshipit-source-id: f72344c
Summary:
It can be useful when debugging infer or the Makefiles themselves to see what
`make` is doing. Instead of editing Makefiles to remove `@` now you can `make
VERBOSE=1`.
This is just `git ls-files | grep -e Makefile -e '.*\.make' | xargs sed -e 's/^\t@/\t$(QUIET)/' -i`, and adding the definition of `QUIET` to Makefile.config.
Reviewed By: jeremydubreil
Differential Revision: D4779115
fbshipit-source-id: e6e4642
Summary:
All tests were redirecting `stderr` into duplicates.txt which made it much harder to see other error messages in stderr (such as uncaught exceptions).
To mitigate it, write duplicates to separate file and don't redirect `stderr` to another file.
Reviewed By: jvillard
Differential Revision: D4728938
fbshipit-source-id: 8ad2fc8
Summary:
This makes sure that one can run `./build-infer.sh` then `make`. Otherwise it's
not always clear what one should do to recompile infer, eg when `make` will
work and when `./build-infer.sh` should be used instead, in particular when the
user doesn't have opam configured for her terminal.
Reviewed By: jberdine
Differential Revision: D4698159
fbshipit-source-id: 5df8059
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: Generalized the CppTrace into a Clang trace because we don't currently have separate checkers for Obj-C and Cpp. Happy to separate them later if there is a good reason
Reviewed By: akotulski
Differential Revision: D4394952
fbshipit-source-id: e288761
Summary: These direct tests were still mostly relying on PHONY targets.
Reviewed By: jberdine
Differential Revision: D4326469
fbshipit-source-id: 37b2d0a
Summary:
In particular, the method for retrieving an element from the array, this should never be nil. Also added a model for count
similar to the one for NSString length.
Reviewed By: ddino
Differential Revision: D4306655
fbshipit-source-id: 0ecb25a
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:
Dealing with symbolic links in project root is tricky. To avoid it, always normalize all paths to sources with `realpath`.
Changes to tests are expected - infer started to resolve symbolic links which screws up with our testing mechanism.
Reviewed By: jberdine
Differential Revision: D4237587
fbshipit-source-id: fe1cb01
Summary:
Run all clang tests with project-root at `infer/tests`. I need it because we'll start resolving symbolic links
soon and some tests would lead outside of project root which means we'd start seeing absolute paths in recorded tests.
Diff that does same thing for java tests: D4233236
Reviewed By: jberdine
Differential Revision: D4233194
fbshipit-source-id: c261a2b
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
Summary:
Record an abstraction of the bug traces in the tests. The abstraction of a
trace is the sequence of descriptions. In practice, descriptions are either
empty, or of the form "start/end/return from/call to procedure X". They seem
pretty stable.
Motivation: there is nothing testing the traces reported by Infer right now,
even though they are surfaced to developers. For instance, Quandary uses
--issues-txt instead of --issues-tests to make sure the traces do not regress.
This change would make this approach more widespread.
Reviewed By: sblackshear
Differential Revision: D4159597
fbshipit-source-id: 9c83952
Summary:
`make` doesn't delay variable evaluation in targets' dependencies, so
`$(OBJECTS)` was always empty. Including clang.make after having defined
`OBJECTS` fixes it.
Reviewed By: jberdine
Differential Revision: D4159522
fbshipit-source-id: 6925f8a
Summary:
When loading results from a json file, sort them. This prints results in some
sane order for both --issues-test and --issues-txt, removing the need for
post-processing of the result.
Reviewed By: cristianoc
Differential Revision: D4167029
fbshipit-source-id: 37e9f1c
Summary:
Instead of the custom filtering done by `InferPrint --issues-tests`, use the
filtering done by `infer` and run without filtering for our e2e tests. We still
test the filtering for our build systems integration tests, and this diff
restores that behaviour for the ant test (hence the bugs removed from
ant/issues.exp).
Also add internal exceptions to most tests to get more signal out of them (eg,
knowing when we add assertion failures and the like).
Retire the old `--issues-tests` to limit the number of ways we do filtering.
Reviewed By: jeremydubreil
Differential Revision: D4131308
fbshipit-source-id: 35805cc
Summary:
This makes the tests depend on much fewer phony targets, thus reducing the need
to rerun the tests when nothing has changed.
Reviewed By: jberdine
Differential Revision: D4118457
fbshipit-source-id: 664b6e3
Summary:
In several places the tests were using whatever 'infer' executable was
found in PATH, instead of the one build from the source to be tested.
Reviewed By: jeremydubreil
Differential Revision: D4065019
fbshipit-source-id: 9b65099
Summary:
Create dummy functions representing the initializers of global variables. This
is so we can implement checks in the backend that can look at the initializer
expressions of global variables. We try not to create these dummy functions
when the initializer is not present, although for some reason we sometimes end
up with empty initializers.
Also add source file info to global variables in the backend (Pvar.re).
Reviewed By: sblackshear
Differential Revision: D3780238
fbshipit-source-id: 2dca87e
Summary:
Convert the last remaining tests to the new direct format: java harness and crashcontext.
Remove what is left of the old testing infrastructure.
Reviewed By: sblackshear
Differential Revision: D3886355
fbshipit-source-id: 5117868
Summary:
Rename symbols in test files so they are not duplicated and files can be analyzed together without affecting analysis results.
Fix some compilation errors, where files could be analyzed but would fail direct compilation.
Add Makefile mimicking the same analysis parameters used for the existing tests.
Reviewed By: dulmarod
Differential Revision: D3869993
fbshipit-source-id: 6db1baf
Summary:
Adding a new mode linters. Now if the analyzer is linters, we do the linters and don't translate,
then, if the analyzer is Infer, we do the translation and the backend and not the linters checks, and the
default is that we do capture, backend and lint checks.
Made the tests separated, which saves time and also shows that the linters mode works.
Reviewed By: jvillard
Differential Revision: D3723472
fbshipit-source-id: 9d828d8
Summary: With this approach, all the global consts will be inlined in the places where they are used.
Reviewed By: dulmarod
Differential Revision: D3703133
fbshipit-source-id: 3c19479
Summary:
Make checks context-aware, to increase flexibility.
As an example application of this change, whenever an atomic property is accessed from within a synchronized block, skip reporting a `DIRECT_ATOMIC_PROPERTY_ACCESS` warning.
Reviewed By: jvillard
Differential Revision: D3648831
fbshipit-source-id: c033f45
Summary: Follow up D3579581. We forget about memory acquired in resources with assumption that developers use raii and free memory in destructors.
Reviewed By: jvillard
Differential Revision: D3614056
fbshipit-source-id: 08fa112
Summary:
Previously, we would translate `throw` with `return`. However, `throw` in
ObjC/C++ is often used to mean "abort". We now translate `throw` the same as
`exit` to prune these paths.
Reviewed By: akotulski
Differential Revision: D3594156
fbshipit-source-id: 81083bb
Summary:
The extra dereference in stmtexpr was wrong. When a dereference is needed, we have a cast.
This was causing one dereference too many, and creating wrong results.
Reviewed By: akotulski
Differential Revision: D3393294
fbshipit-source-id: 7a1ec8e
Summary:Local variable created by conditional operator translation is now declared in scope of whole
procedure. Semantically there is no difference, hopefuly backend will not complain about this
change. Also, nullifying that variable is deferred to preanalysis instead of calling it manually
Reviewed By: jvillard
Differential Revision: D3155733
fb-gh-sync-id: 6cec8fc
fbshipit-source-id: 6cec8fc
Summary:BinaryConditionalOperator should evaluate condition expression once, but we used to evaluate it twice.
Fix translation to account for it.
Reviewed By: dulmarod
Differential Revision: D3179803
fb-gh-sync-id: a801a7e
fbshipit-source-id: a801a7e
Brandon Kieft
Jules Villard
Dulma Churchill
Ezgi Çiçek
Sam Blackshear
Jeremy Dubreil
Jérémie Marguerie
Varun Arora
Dino Distefano
Vivek Dhiman
Dominic Cooney
Mehdi Bouaziz
Daiva Naudziuniene
Roy Li
Meng Zhang
Andrzej Kotulski
Jia Chen
Don Stewart
Martino Luca
Paco Estevez Garcia
Josh Berdine
Cristiano Calcagno