Change the `joinError` functions to have stronger guarantees when used:
* Change the template signature to `RangeOf` to ensure that the
container has `llvm::Error`s.
* Check that the size of the passed container is actually positive
before deferencing `.begin()`.
Introduce the `EagerMaterializationRangeIterator`, which substitutes the
`GeneratorIterator`, and is used to materialize the successors of a
node in the `ScopeGraph`.
In addition, remove the `GeneratorIterator`.
Introduce the `ScopeCloser` and `GotoTarget` annotations in the IR, and
the relative necessary machinery, needed to handle scope closer and goto
edges for the new backend.
A specialization of the `llvm::GraphTraits`, called `ScopeGraph`, that
is able to handle both the above mentioned annotations is provided.
For the `llvm::GraphTraits` implementation, we introduce the
`GeneratorIterator` class, which uses a coroutine to store the status of
the iteration.
A debug logger pass is added, so that we are able to test the
functionality with `FileCheck`.
Implement the `zstdCompress` and `zstdDecompress` functions. Also
implement the `ZstdCompressedOstream` which is a `llvm::raw_ostream`
which compresses data on the fly.
Introduce the `Undirected` GraphTraits, which treats a `MutableEdgeNode`
`GenericGraph` as an undirected graph.
The trait uses the newly introduced `UndirectedChildIterator`, which is
a special custom iterator to get successors and predecessors
concatenated together.
Add some unit tests for `UndirectedChildIterator`.
This fixes a subtle bug in GenericGraph. Basically, if the label of an
Edge was the Empty data structure, whose `operator==` always returns
`true`, the comparison between edges was broken.
Andrea Gussoni