- Both of these constructs are used to represent structs, classes, and unions;
Clang uses the collective term "record" for these.
- The term "aggregate" in `AggregateStorageLocation` implies that, at some
point, the intention may have been to use it also for arrays, but it don't
think it's possible to use it for arrays. Records and arrays are very
different and therefore need to be modeled differently. Records have a fixed
set of named fields, which can have different type; arrays have a variable
number of elements, but they all have the same type.
- Futhermore, "aggregate" has a very specific meaning in C++
(https://en.cppreference.com/w/cpp/language/aggregate_initialization).
Aggregates of class type may not have any user-declared or inherited
constructors, no private or protected non-static data members, no virtual
member functions, and so on, but we use `AggregateStorageLocations` to model all objects of class type.
In addition, for consistency, we also rename the following:
- `getAggregateLoc()` (in `RecordValue`, formerly known as `StructValue`) to
simply `getLoc()`.
- `refreshStructValue()` to `refreshRecordValue()`
We keep the old names around as deprecated synonyms to enable clients to be migrated to the new names.
Reviewed By: ymandel, xazax.hun
Differential Revision: https://reviews.llvm.org/D156788
When dealing with copy constructor, the compiler can emit an
UncheckedDerivedToBase implicit cast for the CXXConstructorExpr of the
base class. In such case, when trying to copy the src storage location
to its destination, we will fail on the assert checking that location
types are the same.
When copying from derived to base class, it is acceptable to break that
assumption to only copy common fields from the base class.
Note: the provided test crashes the process without the changes made to
copyRecord.
Differential Revision: https://reviews.llvm.org/D155844
After this change, `StructValue` is just a wrapper for an `AggregateStorageLocation`. For the wider context, see https://discourse.llvm.org/t/70086.
## How to review
- Start by looking at the comments added / changed in Value.h, StorageLocation.h,
and DataflowEnvironment.h. This will give you a good overview of the semantic
changes.
- Look at the corresponding .cpp files that implement the semantic changes.
- Transfer.cpp, TypeErasedDataflowAnalysis.cpp, and RecordOps.cpp show how the
core of the framework is affected by the semantic changes.
- UncheckedOptionalAccessModel.cpp shows how this complex model is affected by
the changes.
- Many of the changes in the rest of the patch are mechanical in nature.
Reviewed By: ymandel, xazax.hun
Differential Revision: https://reviews.llvm.org/D155446
This serves two purposes:
- Because, today, we only copy the `StructValue`, modifying the destination of
the copy also modifies the source. This is demonstrated by the new checks
added to `CopyConstructor` and `MoveConstructor`, which fail without the
deep copy.
- It lays the groundwork for eliminating the redundancy between
`AggregateStorageLocation` and `StructValue`, which will happen as part of the
ongoing migration to strict handling of value categories (seeo
https://discourse.llvm.org/t/70086 for details). This will involve turning
`StructValue` into essentially just a wrapper for `AggregateStorageLocation`;
under this scheme, the current "shallow" copy (copying a `StructValue` from
one `AggregateStorageLocation` to another) will no longer be possible.
Because we now perform deep copies, tests need to perform a deep equality
comparison instead of just comparing for equal identity of the `StructValue`s.
The new function `recordsEqual()` provides such a deep equality comparison.
Reviewed By: xazax.hun
Differential Revision: https://reviews.llvm.org/D153006
