Similar to the previous patch, this doesn't convert *all* the classes that
could be converted. It also doesn't enforce any new invariants etc.
It *does* include some data we don't use yet: specific token types that are
allowed and optional/required status of sequence items. (Similar to Dmitri's
prototype). I think these are easier to add as we go than later, and serve
a useful documentation purpose.
Differential Revision: https://reviews.llvm.org/D90659
This defines two node archetypes with trivial class definitions:
- Alternatives: the generated abstract classes are trivial as all
functionality is via LLVM RTTI
- Unconstrained: this is a placeholder, I think all of these are going to be
Lists but today they have no special accessors etc, so we just say
"could contain anything", and migrate them one-by-one to Sequence later.
Compared to Dmitri's prototype, Nodes.td looks more like a class hierarchy and
less like a grammar. (E.g. variants list the Alternatives parent rather than
vice versa).
The main reasons for this:
- the hierarchy is an important part of the API we want direct control over.
- e.g. we may introduce abstract bases like "loop" that the grammar doesn't
care about in order to model is-a concepts that might make refactorings
more expressive. This is less natural in a grammar-like idiom.
- e.g. we're likely to have to model some alternatives as variants and others
as class hierarchies, the choice will probably be based on natural is-a
relationships.
- it reduces the cognitive load of switching from editing *.td to working with
code that uses the generated classes
Differential Revision: https://reviews.llvm.org/D90543
So far, only used to generate Kind and implement classof().
My plan is to have this general-purpose Nodes.inc in the style of AST
DeclNodes.inc etc, and additionally a special-purpose backend generating
the actual class definitions. But baby steps...
Differential Revision: https://reviews.llvm.org/D90540
Sam McCall