[PATCH] D82486: RecursiveASTVisitor: don't call WalkUp unnecessarily in post-order traversal

[Dmitri Gribenko via Phabricator via cfe-commits]

gribozavr created this revision.
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gribozavr2 added reviewers: eduucaldas, ymandel.

How does RecursiveASTVisitor call the WalkUp callback for expressions?

- In pre-order traversal mode, RecursiveASTVisitor calls the WalkUp

callback from the default implementation of Traverse callbacks.

- In post-order traversal mode when we don't have a DataRecursionQueue,

RecursiveASTVisitor also calls the WalkUp callback from the default
implementation of Traverse callbacks.

- However, in post-order traversal mode when we have a DataRecursionQueue,

RecursiveASTVisitor calls the WalkUp callback from PostVisitStmt.

As a result, when the user overrides the Traverse callback, in pre-order
traversal mode they never get the corresponding WalkUp callback. However
in the post-order traversal mode the WalkUp callback is invoked or not
depending on whether the data recursion optimization could be applied.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D82486

Files:
  clang/include/clang/AST/RecursiveASTVisitor.h
  clang/unittests/Tooling/RecursiveASTVisitorTests/Callbacks.cpp

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