Previously we were calling glrRecover() ad-hoc at the end of input.
Two main problems with this:
- glrRecover() on two separate code paths is inelegant
- We may have to recover several times in succession (e.g. to exit from
nested scopes), so we need a loop at end-of-file
Having an actual shift action for an EOF terminal allows us to handle
both concerns in the main shift/recover/reduce loop.
This revealed a recovery design bug where recovery could enter a loop by
repeatedly choosing the same parent to identically recover from.
Addressed this by allowing each node to be used as a recovery base once.
Differential Revision: https://reviews.llvm.org/D130550
- when printing a shared node for the second time, don't print its children
(This keeps output proportional to the size of the structure)
- when printing a shared node for the second time, print its type only, not rule
(for consistency with above: don't dump details of nodes twice)
- don't abbreviate shared nodes, to ensure we can prune the tree there
Differential Revision: https://reviews.llvm.org/D128805
Parse forest is the output of the GLR parser, it is a tree-like DAG
which presents all possible parse trees without duplicating subparse structures.
This is a patch split from https://reviews.llvm.org/D121150.
Differential Revision: https://reviews.llvm.org/D122139
Sam McCall