forked from OSchip/llvm-project
814e7974c6
Summary: The goal is to allow analyses such as clang-tidy checks to run on a subset of the AST, e.g. "only on main-file decls" for interactive tools. Today, these become "problematically global" by running RecursiveASTVisitors rooted at the TUDecl, or by navigating up via ASTContext::getParent(). The scope is restricted using a set of top-level-decls that RecursiveASTVisitors should be rooted at. This also applies to the visitor that populates the parent map, and so the top-level-decls are considered to have no parents. This patch makes the traversal scope a mutable property of ASTContext. The more obvious way to do this is to pass the top-level decls to relevant functions directly, but this has some problems: - it's error-prone: accidentally mixing restricted and unrestricted scopes is a performance trap. Interleaving multiple analyses is common (many clang-tidy checks run matchers or RAVs from matcher callbacks) - it doesn't map well to the actual use cases, where we really do want *all* traversals to be restricted. - it involves a lot of plumbing in parts of the code that don't care about traversals. This approach was tried out in D54259 and D54261, I wanted to like it but it feels pretty awful in practice. Caveats: to get scope-limiting behavior of RecursiveASTVisitors, callers have to call the new TraverseAST(Ctx) function instead of TraverseDecl(TU). I think this is an improvement to the API regardless. Reviewers: klimek, ioeric Subscribers: mgorny, cfe-commits Differential Revision: https://reviews.llvm.org/D54309 llvm-svn: 346847 |
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| clang | ||
| clang-c | ||
| CMakeLists.txt | ||