[all-commits] [llvm/llvm-project] b67263: [clang][deps] Ensure deterministic filename case

[Jan Svoboda via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: b672638dbc7cec9a51826520e8f8aef276bac3ee
      https://github.com/llvm/llvm-project/commit/b672638dbc7cec9a51826520e8f8aef276bac3ee
  Author: Jan Svoboda <jan_svoboda at apple.com>
  Date:   2022-04-08 (Fri, 08 Apr 2022)

  Changed paths:
    M clang/include/clang/Lex/DirectoryLookup.h
    M clang/lib/Lex/HeaderSearch.cpp
    A clang/test/ClangScanDeps/header-search-case-sensitivity.c

  Log Message:
  -----------
  [clang][deps] Ensure deterministic filename case

The dependency scanner can reuse single FileManager instance across multiple translation units. This may lead to non-deterministic output depending on which TU gets processed first.

One of the problems is that Clang uses DirectoryEntry::getName in the header search algorithm. This function returns the path that was first used to construct the (shared) entry in FileManager. Using DirectoryEntryRef::getName instead preserves the case as it was spelled out for the current "get directory entry" request.

rdar://90647508

Reviewed By: dexonsmith

Differential Revision: https://reviews.llvm.org/D123229