[PATCH] D65486: [clangd] Ignore semicolons, whitespace, and comments in SelectionTree.

[Sam McCall via Phabricator via cfe-commits]

sammccall added a comment.

It occurs to me that `claim` is `O(node_tokens + log total_tokens)` which is bad when the nodes are large.

Indeed for an input like `namespace { namespace { namespace { ... } } }` time is quadratic.

I think this is probably fine in practice. Against adversarial input clang certainly can take exponential time, and easily crash too.

If we do need to fix it my best idea is to give each "uninteresting" TokInfo (that is, !selected || claimed) a pointer to the next TokInfo with different flags. This would allow iteration to quickly skip over contiguous ranges one they had been traversed once.


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D65486/new/

https://reviews.llvm.org/D65486