Summary: Add `QualifiedCppName.t` and some functions to manipulate it. More places will start using this type (such as `Procnames` or `Typ.Name`) in later diff
Reviewed By: jberdine
Differential Revision: D4738991
fbshipit-source-id: 8f20dd6
Summary: Now that all the checkers are now run in a way that will prevent conflicts between them, we can make this change that was breaking the analysis.
Reviewed By: jvillard
Differential Revision: D4621953
fbshipit-source-id: f17c729
Summary:
One limitation of Eradicate is that certain nullability patterns are not expressible using simply the `Nullable` annotation.
One such pattern is using the knowledge that a function returns null when passed null, but returns an object otherwise.
The annotation `PropagatesNullable` is a variant of `Nullable` applied to parameters when their value propagates to the return value.
A method annotated
```
B m(PropagatesNullable A x) { return x == null ? x : B(x); }
```
indicates that `m` returns null if `x` is null, or an object of class `B` if the argument is not null.
Examples with multiple parameters are in the test cases.
This diff builds some infrastructure for annotation transformers: the example above represents the identity function on nullability annotations.
Reviewed By: jvillard
Differential Revision: D4705938
fbshipit-source-id: 9f6194e
Summary:
Before, `trace_of_pname` only grabbed unprotected writes from the summary, so the traces ending in an unprotected read were truncated.
We now look at reads too when appropriate.
Reviewed By: peterogithub
Differential Revision: D4719740
fbshipit-source-id: 28f6e63
Summary: Now, running `infer -a checkers -- ...` will also run the ThreadSafety checker
Reviewed By: sblackshear
Differential Revision: D4691330
fbshipit-source-id: 04fc781
Summary: Run all the checkers one after each other, which allows the Infer AI framework to run several checkers together, including the possibility for them to collaborate.
Reviewed By: sblackshear
Differential Revision: D4621838
fbshipit-source-id: e264d67
Summary:
Changes every checker to take a summary as parameter and return the updated summary to the next checker. Since several operations, like `Reporting.log_*` are modifying the summary in memory by loading them from the in-memory cache of summaries, we currently need to rely on `Specs.get_summary_unsafe` to return the updated version of the summary.
This diff allows to change the API of `Reporting` to take a summary as input and progressively remove all the calls `Specs.get_summary_unsafe` independently from adding the possibility to run several checkers at the same time. The final objective to have every checker just passing around the summary of the procedure being analyzed, and having the in-memory cache only use to store the summaries of the callees.
Reviewed By: sblackshear
Differential Revision: D4649252
fbshipit-source-id: 98f7ca7
Summary:
When both an unprotected write and a read/write race emanate from the same line,
undoubtedly because of interprocedurality, strip the read/write report (for now).
Perhaps report the info in more succinct form later, but keep to one report/line.
Reviewed By: sblackshear
Differential Revision: D4685102
fbshipit-source-id: 291cf20
Summary: This cleans up the domain/transfer functions, and it also means that we can now track reads that occur under synchronization.
Reviewed By: peterogithub
Differential Revision: D4674243
fbshipit-source-id: 8e13656
Summary:
Provide proper constructor functions for all Typenames following `Typename.Java` module.
Always use those constructor functions.
Reviewed By: jeremydubreil
Differential Revision: D4673943
fbshipit-source-id: 81625c2
Summary: This allows to run the analysis of every procedure on-demand separately from the cluster callbacks
Reviewed By: sblackshear
Differential Revision: D4664936
fbshipit-source-id: d218328
Summary:
It used to be string which:
1. Doesn't have enough information for parametric models
2. Doesn't have good type
Changing this blows up in clang frontend, but I think it's for the better
Reviewed By: jberdine
Differential Revision: D4667633
fbshipit-source-id: 9f61bf1
Summary: Previously, we wouldn't report races where the write was under synchronization.
Reviewed By: peterogithub
Differential Revision: D4658850
fbshipit-source-id: e9f4c41
Summary:
In order to be able to report races like
```
synchronized write() {
this.f = ...
}
read() {
return this.f;
}
```
, we need to track writes that happen inside of synchronization as well as writes that happen outside of synchronization.
This diff takes a step toward making that possible by defining an "AccessDomain" mapping a precondition for the safety of a write ( {Safe, SafeIf i, Unsafe} =~ {true, owned(i), false} ) to a set of writes that are safe if the precondition will hold.
We're not actually tracking safe writes yet, but this domain will make it easy to do so.
This also lets us kill the conditional writes/unconditional writes combo, which was a bit clumsy
Reviewed By: peterogithub
Differential Revision: D4620153
fbshipit-source-id: 2d9c5ef
Summary: I accidentally save a summary with the wrong procedure name, which was affecting the analysis in some weird way. This makes this case no longer possible
Reviewed By: cristianoc
Differential Revision: D4654002
fbshipit-source-id: 9fcbe4e
Summary: This function was actually doing the same as `Idenv.create`.
Reviewed By: cristianoc
Differential Revision: D4654241
fbshipit-source-id: 87c098b
Summary:
This is part of the plan to have every checker take a summary as input, and return the updated sumamry as output. Doing so, we can run all the registered checkers in sequence for every method
This diff change the type of `Ondemand.analyze_ondemand` to return the analysis summary.
Reviewed By: sblackshear
Differential Revision: D4626918
fbshipit-source-id: f8ad928
Summary:
Stop multiple reports per line happening. These come about
because of interprocedural access to multiple fields. Present one trace,
and summary information about other accesses.
Reviewed By: sblackshear
Differential Revision: D4636232
fbshipit-source-id: 9039fea
Summary:
With the ondemand analysis framework, the concept of timestamp was only being use to check if a procedure has already been analyzed. There was already a concept of "active" procedure for the procedure that were already being analyzed. This revision removes the concept of timestamp and merge it with the concept of analysis status.
This can be simplified further once the analysis always goes through `Ondemand.analyze`.
Reviewed By: cristianoc
Differential Revision: D4610371
fbshipit-source-id: 0fc516b
Summary:
Polymorphic models, and type environment refinements, need mutual
references between general types and struct types.
Reviewed By: cristianoc
Differential Revision: D4620076
fbshipit-source-id: f9d01e6
Summary: Rather than having three separate annotations related to checking/assuming thread-safety, let's just have one annotation instead.
Reviewed By: peterogithub
Differential Revision: D4605258
fbshipit-source-id: 17c935b
Summary: distinguish writes via method calls (e.g., add) from writes via assignment in the error messages
Reviewed By: sblackshear
Differential Revision: D4611748
fbshipit-source-id: 7594d3b
Summary: It seems that we need to store the summary to disk in `Summary.write_summary`. The previous code was just saving it to the in-memory cache of summaries.
Reviewed By: sblackshear
Differential Revision: D4611090
fbshipit-source-id: 9973679
Summary: The function `Checkers.ST.store_summary` was only used in one place. This revision moves the functionality to the only place where this function was used, except the part swallowing `Sys_error` which may have the bad side-effect of making issues like race-conditions silent.
Reviewed By: cristianoc
Differential Revision: D4608790
fbshipit-source-id: b84c8ce
Summary: Report at most one read/write race or unprotected write per access path per method
Reviewed By: sblackshear, jvillard
Differential Revision: D4590815
fbshipit-source-id: 3c3a9d9
Summary:
To address a common source of false positives observed in D4494901.
We don't do anything with `release` yet, but can model it as releasing ownership in the future if we want to enforce correct usage of `SynchronizedPool`'s.
Reviewed By: peterogithub
Differential Revision: D4593635
fbshipit-source-id: 621e937
Summary: Reports on reads that have one or more conflicting writes. When you report, say which other methods race with it.
Reviewed By: sblackshear
Differential Revision: D4538793
fbshipit-source-id: 47ce700
Summary: Thread-local variables can't be shared between threads, so it's safe to mutate them outside of synchronization
Reviewed By: jeremydubreil
Differential Revision: D4568316
fbshipit-source-id: 0634cad
Summary:
Enrich the domain of SIOF to contain, as well as the globals needed by a
procedure, the globals that the procedure initializes. Also add the possibility
to model some procedures as initializing some variables. Use that mechanism to
teach the checker about `std::ios_base::Init`.
Reviewed By: mbouaziz
Differential Revision: D4588284
fbshipit-source-id: d72fc87
Summary:
Reimplement whitelists as a match against a single regexp. This allows one to
precompile the whitelist regexp to make fast check against a whitelist of fuzzy
qualifiers, instead of checks linear in the number of items in the whitelist.
Reviewed By: akotulski
Differential Revision: D4588278
fbshipit-source-id: 3bac614
Summary:
This gives a way for users to flag safe methods regarding SIOF, for instance if
the problematic paths in the method cannot happen before `main()` has started.
Reviewed By: akotulski
Differential Revision: D4578700
fbshipit-source-id: 6542dcf
Summary:
A good first step in order to run multiple checkers together is to prevent the analysis the analysis to side effect on the summaries of the method being analyzed from disk, or the shared specs summary. The idea is that `Ondemand` creates a summary for the procedure being analyzed and only saves the summary once all the checkers have been run. The summary for the caller (i.e. the procedure being analyzed) should never be looked up from disk during the analysis. In other words, the analysis should only ever lookup the summaries of the callees and the proposed solution to enforce this is to have `Ondemand.analyze_proc_name` be the only way to lookup the summary of a procedure.
Another objective is to make sure that the summaries are never saved to disk more than once.
Reviewed By: sblackshear
Differential Revision: D4549764
fbshipit-source-id: f0a6e21
Summary:
We waste a lot of space storing the types of field accesses and comparing them sets/maps with access paths.
Yet almost none of the code ever looks at these types (only a tiny piece of code in thread-safety).
If we know the base type, we have enough information to recover the type of the field.
Let's do that instead.
Reviewed By: jeremydubreil
Differential Revision: D4567996
fbshipit-source-id: e7fd2da
Summary: Should stop us from reporting on benign races of fields that are caching resources.
Reviewed By: peterogithub
Differential Revision: D4538037
fbshipit-source-id: 15236b4
Summary: This will be important for maintaining ownership of `View`'s, which involve a lot of casting.
Reviewed By: peterogithub
Differential Revision: D4520441
fbshipit-source-id: fdef226
Summary:
Previously, we would lose track of ownership in code like
```
Obj owned = new Obj();
Obj stillOwned = id(owned); // would lose ownership here
stillOwned.f = ... // would report false alarm here
```
This diff partially addresses the problem by adding a notion of "unconditional" (always owned) or "conditional" (owned if some formal at index i is owned) ownership.
Now we can handle simple examples like the one above.
I say "partially" because we still can't handle cases where there are different reasons for conditional ownership, such as
```
oneOrTwo(Obj o1, Obj o2) { if (*) return o1; else return o2; } // we won't understand that this maintains ownership if both formals are owned
Obj stillOwned = oneOrTwo(owned1, owned2);
stillOwned.f = ... // we'll report a false alarm here
```
This can be addressed in the future, but will require slightly more work
Reviewed By: peterogithub
Differential Revision: D4520069
fbshipit-source-id: 99c7418
Summary: This will make it a cinch to track new "attributes" of memory locations, and to propagate more complex attributes such as conditional ownership (coming in a future diff).
Reviewed By: peterogithub
Differential Revision: D4523143
fbshipit-source-id: 57aa133
Summary: Being forced to separately define `pp_element`/`pp_key` is uneccessary and makes it more cumbersome to create a set/map from an existing module that already defines `pp`.
Reviewed By: jeremydubreil
Differential Revision: D4517308
fbshipit-source-id: 9b17c9c
Summary:
At one point I thought we'd want to have lots of different schedulers for things like exploring loops in different orders, but that hasn't materialized.
Let's make the common use-case simpler by hiding the `Scheduler` parameter inside the `AbstractInterpreter` module.
We can always expose `MakeWithScheduler` later if we want to.
Reviewed By: jberdine
Differential Revision: D4508095
fbshipit-source-id: 726e051
Summary:
This fixes false positives we had in fields written by callees of a constructor (see new E2E test).
This is also a bit cleaner than what we did before; instead of special-casing constructors, we just use the existing ownership concept.
Reviewed By: peterogithub
Differential Revision: D4505161
fbshipit-source-id: a739ebc
Summary:
Constants are always "owned" in the sense that no one can mutate them.
In code like
```
Obj getX(boolean b) {
if (b) {
return null;
}
return new Obj();
}
```
, we need to understand this in order to infer that the returned value is owned.
This should fix a few FP's that I've seen.
Reviewed By: peterogithub
Differential Revision: D4485452
fbshipit-source-id: beae15b
Summary: The method `junit.framework.TestCase.setUp()` is always run before the other methods by the JUnit testing framework. So the method act as a class initializer.
Reviewed By: sblackshear
Differential Revision: D4487371
fbshipit-source-id: 1998801
Summary:
This diff adds a set of access paths holding a value returned from a method annotated with Functional to the domain.
If a "functional" value is written to a field, we won't count that right as an unprotected access.
The idea is to be able to use the Functional annotation to get rid of benign race false positive, such as:
```
Functional T iAlwaysReturnTheSameThing();
T mCache;
T memoizedGetter() {
if (mCache == null) {
mCache = iAlwaysReturnTheSameThing();
}
return mCache;
}
```
Although there is a write-write race on `mCache`, we don't care because it will be assigned to the same value regardless of which writer wins.
Reviewed By: peterogithub
Differential Revision: D4476492
fbshipit-source-id: cfa5dfc
Summary:
We warn on unsafe accesses to fields that occur in a public method (or are reachable from a public method).
We ought not to consider VisibleForTesting methods as public, since they are only public for testing purposes.
Reviewed By: peterogithub
Differential Revision: D4477648
fbshipit-source-id: 5f58914
Summary:
The thread-safety and annotation reachibility analyses were defining ugly custom versions of override_exists with refs.
Let's give them a canonical, ref-free version instead.
Reviewed By: jberdine
Differential Revision: D4475777
fbshipit-source-id: 0bb45fc
Summary: Simple model for List methods that write to the collection.
Reviewed By: peterogithub
Differential Revision: D4453381
fbshipit-source-id: 19edc51
Summary:
One of the things that confuses me about the current annotations API is that there's a lot of ways to do the same thing.
Some of the concepts like `annotated_signature` are only really needed by Eradicate.
This diff removes usages of `annotated_signature` outside of Eradicate (everyone else was just using `get_annotated_signature` as a roundabout way to get the return annotation of a procedure).
In the future, I'll move `get_annotated_signature` and other Eradicate-specific functionality into its own module inside the Eradicate directory.
Reviewed By: jberdine
Differential Revision: D4472058
fbshipit-source-id: 5bb0846
Summary:
`pdesc_has_annot` checks the annotations of both the return values and the parameters, which seems like a bad idea in general.
The client should have to specify which annotations they actually care about.
Converting existing uses of `pdesc_has_annot` to what I read as the intended behavior (checking the return annotation).
Will make better use of the other new functions in a follow-up.
Reviewed By: jeremydubreil
Differential Revision: D4469885
fbshipit-source-id: de5531e
Summary:
Previously, we would correctly be silent on code like `x = new T(); x.f = ...`, but would wrongly warn on code like `x = makeT(); x.f = ...`.
The reason is that we only allowed ownership through direct allocation.
This diff adds a boolean that specifies whether the return value is owned as part of the summary.
This allows us to correctly handle many common cases of (transitively) returning a freshly allocated object, but still won't work for understanding that ownership is maintained in examples like
`x = new T(); y = id(x); y.f = ...`.
Reviewed By: jvillard
Differential Revision: D4456864
fbshipit-source-id: b5eec02
Summary:
Remove the remaining uses of polymorphic equality `=`.
In case of basic types, this is replaced by String.equal or Int.equal.
In case of `= []`, this is replaced by `List.is_empty`.
In case of `= None`, this is replaced by `is_none`.
In case of a datatype definition such as `type a = A | B`,
a `compare_a` function is defined by adding `type a = A | B [@deriving compare]`
and a `equal_a` function is defined as `let equal_a = [%compare.equal : a]`.
In case of comparison with a polymorphic variant `= `Yes`, the equality
defined in `PVariant.(=)` is used. Typically, `open! Pvariant` is added
at the beginning of the file to cover all the uses.
Reviewed By: jberdine
Differential Revision: D4456129
fbshipit-source-id: f31c433
Summary:
In code like
```
foo(o) {
iWriteToF(o)
}
```
, the condtional write to `f` in `iWriteToF` should become a conditional write for `foo`.
Reviewed By: peterogithub
Differential Revision: D4429160
fbshipit-source-id: f111ac4
Summary:
In code like
```
foo() {
Object local = new Object();
iWriteToAField(local);
}
```
, we don't want to warn because the object pointed to by `local` is owned by the caller, then ownership is transferred to the callee.
This diff supports this by introducing a notion of "conditional" and "unconditional" writes.
Conditional writes are writes that are rooted in a formal of the current procedure, and they are safe only if the actual bound to that formal is owned at the call site (as in the `foo` example above).
Unconditional writes are rooted in a local, and they are only safe if a lock is held in the caller.
Reviewed By: peterogithub
Differential Revision: D4429131
fbshipit-source-id: 2c6112b
Summary:
Races on volatile fields are less concerning than races on non-volatile fields because at least the read/write won't result in garbage.
For now, let's de-prioritize these writes by ignoring them.
Reviewed By: peterogithub
Differential Revision: D4434023
fbshipit-source-id: 05043ba
Summary:
Also make sure we don't introduce deprecated options in our repo, eg when
calling infer from infer.
Reviewed By: jeremydubreil
Differential Revision: D4430379
fbshipit-source-id: 77ea7fd
Summary:
Make the html output available to checkers when -g is used on the command-line.
A checker needs to call a function to start and finish the processing of each node,
and add prints during the processing.
This diff illustrates the case for Eradicate, by adding printing of the pre-state
and post-states.
Reviewed By: sblackshear
Differential Revision: D4421379
fbshipit-source-id: 67501ba
Summary:
If an access path rooted in some parameter `p` is accessed outside of synchronizaton, but `p` is owned by the caller, then we should not warn.
We will implement this by separating writes into "conditional" (safe if a certain parameter is owned by the caller" and "unconditional" (safe only if the caller synchronizes appropriately).
This diff just introduces the map type for conditional writes and changes the transfer functions accordingly.
We'll actually use the map in a follow-up.
Reviewed By: peterogithub
Differential Revision: D4400987
fbshipit-source-id: d2b8af8
Summary:
Similar to marking classes ThreadConfined, we want to support marking fields as well.
The intended semantics are: don't warn on writes to the marked field outside of syncrhonization, but continue to warn on accesses to subfields.
Reviewed By: peterogithub
Differential Revision: D4406890
fbshipit-source-id: af8a114
Summary: This will be useful in upcoming changes to the thread-safety analysis as well.
Reviewed By: dkgi
Differential Revision: D4402146
fbshipit-source-id: c750127
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:
Adding models that allow us to warn on unguarded accesses to subclasses of `Map`, but not on accesses of threadsafe containers like `ConcurrentMap`.
Lots more containers to model later, but stopping at `Map`s for now to make sure the approach looks ok.
Reviewed By: jvillard
Differential Revision: D4385306
fbshipit-source-id: d791eee
Summary: These methods should only be called from other methods that also run on the UI thread, and they should not be starting new threads.
Reviewed By: peterogithub
Differential Revision: D4383133
fbshipit-source-id: 6cb2e40
Summary:
A domain should not definite its initial state, since distinct users of the domain may want to choose different initial values.
For example, one user might want to bind all of the formals to some special values, and one user might want the initial domain to be an empty map
This diff makes this distinction clear in the types by (a) requiring the initial state to be passed to the abstract interpreter and (b) lifting the requirement that abstract domains define `initial`.
Reviewed By: jberdine
Differential Revision: D4359629
fbshipit-source-id: cbcee28
Summary:
There's a lot of boilerplate work to be done when adding a new kind of source.
This diff tries to reduce the boilerplate by making a functor do all the work.
The functor:
(1) adds a notion of "footprint kind" to the source
(2) packages the source with a call site
Reviewed By: jvillard
Differential Revision: D4349224
fbshipit-source-id: 5e1701a
Summary:
We currently can only model the return values of functions as sources.
In order to model inputs of endpoints as sources, we need the capability to treat the formals of certain functions as sources too.
This diff adds that capability by adding a function for getting the tainted sources to the source module, then using that info in the analysis.
Reviewed By: jeremydubreil
Differential Revision: D4314738
fbshipit-source-id: dd7d423
Summary:
Previously, summaries worked by flattening the access tree representing the post of the procedure into (in essence) a list of functions from caller input traces to callee output traces.
This is inefficient in many ways, and is also much more complex than just using the original access tree as the summary.
One big inefficiency of the old way is this: calling `Trace.append` is slow, and we want to do it as few times as possible.
Under the old summary system, we would do it at most once for each "function" in the summary list.
Now, we'll do it at most once for each node in the access tree summary.
This will be a smaller number of calls, since each node can summarize many input/output relationships.
Reviewed By: jeremydubreil
Differential Revision: D4271579
fbshipit-source-id: 34e407a
Summary:
This commit avoids using the join operator for the widening
of the Map functor in ```abstractDomain.ml```
and ensures termination when ```ValueDomain``` is infinite
by using ```ValueDomain.widen```.
Closes https://github.com/facebook/infer/pull/535
Differential Revision: D4319797
Pulled By: sblackshear
fbshipit-source-id: 16f15e4
Summary: Don't warn on NotThreadSafe class, particularly when super is ThreadSafe
Reviewed By: sblackshear
Differential Revision: D4334417
fbshipit-source-id: 0df3b9d
Summary:
SuppressWarnings annotations are hardly used and add considerable
complexity due to requiring recompilation with an annotation processor.
Reviewed By: jvillard
Differential Revision: D4312193
fbshipit-source-id: c4fc07e
Summary:
Change the domain of SIOF to be based on sets of pvar * location instead of
single pvars. This allows us to group several accesses together. However, we
still get different trace elems for different instructions in a proc. We do two
things to get around this limitation and get a trace where all accesses within
the same proc are grouped together, instead of one trace for each access:
1. A post-processing phase at the end of the analysis of one proc collects all
the globals directly accessed in the proc into a single trace elem.
2. When creating the error trace, unpack this set into several trace elements
to see each access (at its correct location) separately in the trace.
This is a bit hacky and another way would be to extend the API of traces to
handle in-procedure accesses natively instead of shoe-horning them. However
since SIOF is the only one to use this, it introduces less boilerplate to do it
that way for now.
Also, a few .mlis for good measure.
Reviewed By: sblackshear
Differential Revision: D4299070
fbshipit-source-id: 3bbb5c2
Summary:
If these collections don't encapsulate their state properly, there are bigger problems than thread safety issues :).
Plus, these warnings are less-than-actionable for non-Guava maintainers.
Reviewed By: peterogithub
Differential Revision: D4324277
fbshipit-source-id: cacfbf0
Summary:
Maintain an "ownership" set of access paths that hold locally allocated memory that has not escaped.
This memory is owned by the current procedure, so modifying it outside of synchronization is safe.
If an owned access path does escape to another procedure, we remove it from the ownership set.
Reviewed By: peterogithub
Differential Revision: D4320034
fbshipit-source-id: 64f9169
Summary: This is required to maintain a set of owned access paths in a subsequent diff.
Reviewed By: jberdine
Differential Revision: D4318859
fbshipit-source-id: bd1a9fa
Summary:
These checks were useful when developing Quandary, but do not fire anymore.
`AccessPath.raw_equal` is implicated as one of the top time-consuming functions in Quandary, so gating the assertion that calls it needlessly might save us some time.
Also minor cleanup: made the error messages a bit clearer and added an mli.
Reviewed By: jeremydubreil
Differential Revision: D4323653
fbshipit-source-id: 2a723b5
Summary:
Before, the Interprocedural functor was a bit inflexible. You couldn't do custom postprocessing like normalizing the post state or coverting the post from an astate type to a summary type.
Now, you can do whatever you want by passing a custom `~compute_post` function.
Since `AbstractInterpreter.compute_post` can be used by clients who don't care to do anything custom, this doesn't create too much boilerplate.
Reviewed By: jvillard
Differential Revision: D4309877
fbshipit-source-id: 8d1d85d
Summary:
Before the diff, the code was considering as Nullable any annotation ending with `...Nullable`, including `SuppressParameterNotNullable`.
Closes#533
Reviewed By: jberdine
Differential Revision: D4317356
fbshipit-source-id: 6091c0f
Summary: We're about to add another element to the abstract domain, and a 4-tuple is a bit too cumbersome to work with.
Reviewed By: jberdine
Differential Revision: D4315292
fbshipit-source-id: d04699f
Summary:
Use In_channel and Out_channel operations instead of those in Pervasives. Don't
use physical equality on values that aren't heap-allocated since it doesn't help
the compiler generate faster code and the semantics is unspecified. Also use
phys_equal for physical equality.
Reviewed By: sblackshear
Differential Revision: D4232459
fbshipit-source-id: 36fcfa8
Andrzej Kotulski
Sam Blackshear
Martino Luca
Jeremy Dubreil
Dulma Churchill
Cristiano Calcagno
Peter O'Hearn
Josh Berdine
Jules Villard
Kihong Heo
Kihong Heo