vsavchenko marked an inline comment as done.
vsavchenko added inline comments.
================
Comment at: clang/lib/StaticAnalyzer/Core/SVals.cpp:151
+ Optional<QualType> VisitNonLocLazyCompoundVal(nonloc::LazyCompoundVal LCV) {
+ return Visit(LCV.getRegion());
+ }
----------------
NoQ wrote:
> 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`.
> In order to obtain a live LazyCompoundVal specimen for testing purposes.
That's not a problem:
```
TestUnion d = {.c=b};
```
does produce LazyCompundVal and we don't get a pointer, but the value type.
That's why I was asking how I can construct an example when this current
implementation fails.
> 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.
Value categories are orthogonal to types, so I don't see why we should care for
those in `getType`. How do you think it should affect this particular
functionality?
Repository:
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https://reviews.llvm.org/D104550/new/
https://reviews.llvm.org/D104550
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