[PATCH] D104550: [analyzer] Implement getType for SVal

[Artem Dergachev via Phabricator via cfe-commits]

NoQ added inline comments.


================
Comment at: clang/lib/StaticAnalyzer/Core/SVals.cpp:151
+  Optional<QualType> VisitNonLocLazyCompoundVal(nonloc::LazyCompoundVal LCV) {
+    return Visit(LCV.getRegion());
+  }
----------------
vsavchenko wrote:
> NoQ wrote:
> > This is correct except you need to get the value type, not the pointer type.
> > 
> > `LazyCompoundVal` is a `prvalue` and its parent region is the location in which this `prvalue` resided some time in the past. So the parent region is of the right type and it's always typed but you need the pointee type.
> OK then, can you maybe hint how can I write a test where this is going to be a pointer type (or maybe then `getType` for regions works incorrectly).
Regions have `getLocationType()` (the pointer type) and `getValueType()` (the pointee type). I think you need to call the latter directly in this case, bypassing recursion.

In order to obtain a live `LazyCompoundVal` specimen for testing purposes, you need to load an entire compound object (not necessarily represented by a `CompoundVal`) from Region Store.

Eg.,
```lang=c
  struct MyStruct a;
  // ...
  struct MyStruct b = a; // Avoid C++ though, constructors are a different beast.
```

Or you could construct one directly. But that, of course, wouldn't give you any hints about the appropriate type.

> maybe then `getType` for regions works incorrectly

Hmm that's actually a good separate question. How do you know if a region represents a prvalue of pointer type or a glvalue of pointee type (including, but not limited to, references)? This can't be figured out without more context just by looking at the `SVal`.


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  https://reviews.llvm.org/D104550/new/

https://reviews.llvm.org/D104550