- For a better understand of what the unsupported cases are, we add
more information to the debug note---a string of ancestor AST nodes
of the unclaimed DRE. For example, an unclaimed DRE p in an
expression `*(p++)` will result in a string starting with
`DRE ==> UnaryOperator(++) ==> Paren ==> UnaryOperator(*)`.
- To find out the most common patterns of those unsupported use cases,
we add a simple script to build a prefix tree over those strings and
count each prefix. The script reads input line by line, assumes a
line is a list of words separated by `==>`s, and builds a prefix tree
over those lists.
Reviewed by: t-rasmud (Rashmi Mudduluru), NoQ (Artem Dergachev)
Differential revision: https://reviews.llvm.org/D158561
