[all-commits] [llvm/llvm-project] 1eb74f: [libc++] Remove the chrono include from algorithm

[Ian Anderson via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 1eb74f7e83ffb3f9d00e5987cead3b12e00bbe82
      https://github.com/llvm/llvm-project/commit/1eb74f7e83ffb3f9d00e5987cead3b12e00bbe82
  Author: Ian Anderson <iana at apple.com>
  Date:   2023-04-22 (Sat, 22 Apr 2023)

  Changed paths:
    M libcxx/docs/ReleaseNotes.rst
    M libcxx/include/algorithm
    M libcxx/test/libcxx/transitive_includes/cxx03.csv
    M libcxx/test/libcxx/transitive_includes/cxx11.csv
    M libcxx/test/libcxx/transitive_includes/cxx14.csv
    M libcxx/test/libcxx/transitive_includes/cxx17.csv

  Log Message:
  -----------
  [libc++] Remove the chrono include from algorithm

algorithm's include of chrono causes include cycles:

```
algorithm -> chrono -> __chrono/convert_to_tm.h -> __chrono/statically_widen.h -> __format/concepts.h -> __format/format_parse_context.h -> string_view -> algorithm

algorithm -> chrono -> __chrono/convert_to_tm.h -> __chrono/statically_widen.h -> __format/concepts.h -> __format/format_parse_context.h -> string_view -> functional -> __functional/boyer_moore_searcher.h -> array -> algorithm

algorithm -> chrono -> __chrono/convert_to_tm.h -> __chrono/statically_widen.h -> __format/concepts.h -> __format/format_parse_context.h -> string_view -> functional -> __functional/boyer_moore_searcher.h -> unordered_map -> algorithm

algorithm -> chrono -> __chrono/convert_to_tm.h -> __chrono/statically_widen.h -> __format/concepts.h -> __format/format_parse_context.h -> string_view -> functional -> __functional/boyer_moore_searcher.h -> vector -> algorithm
```

This is a problem for clang modules after the std mega module is broken up, because it becomes a module cycle which is a hard error.

All of the includes in the `__chrono` and `__format` headers are being used and so can't be removed. algorithm's include of chrono is already removed in C++20, whereas the array, string_view, unordered_map, vector includes of algorithm aren't removed until C++23 (and it's 4x the includes that would need removing). Unconditionally remove the chrono include from algorithm in all versions, so that the module breakup can happen (the module has to apply to all C++ versions).

Reviewed By: Mordante, #libc

Differential Revision: https://reviews.llvm.org/D148405