[PATCH] D67567: New ClangTidy checks to warn about misusing dispatch_once_t

[Michael Wyman via Phabricator via cfe-commits]

mwyman created this revision.
mwyman added reviewers: benhamilton, hokein, stephanemoore.
Herald added subscribers: cfe-commits, mgorny.
Herald added a project: clang.

Adds two new ClangTidy checks:

- misc-dispatch-once-assignment: warns about assignment to a dispatch_once_t variable. In code reviews I've encountered enough attempts to "reset" a dispatch_once.
- misc-dispatch-once-nonstatic: warns about dispatch_once_t variables not in static or global storage. This catches a missing static for local variables in e.g. singleton initialization behavior, and also warns on storing dispatch_once_t values in Objective-C instance variables. C/C++ struct/class instances may potentially live in static/global storage, and are ignored for this check.

The osx.API static analysis checker can find the non-static storage use of dispatch_once_t; I thought it useful to also catch these issues in clang-tidy when possible.


Repository:
  rCTE Clang Tools Extra

https://reviews.llvm.org/D67567

Files:
  clang-tools-extra/clang-tidy/misc/CMakeLists.txt
  clang-tools-extra/clang-tidy/misc/DispatchOnceAssignmentCheck.cpp
  clang-tools-extra/clang-tidy/misc/DispatchOnceAssignmentCheck.h
  clang-tools-extra/clang-tidy/misc/DispatchOnceNonstaticCheck.cpp
  clang-tools-extra/clang-tidy/misc/DispatchOnceNonstaticCheck.h
  clang-tools-extra/clang-tidy/misc/MiscTidyModule.cpp
  clang-tools-extra/docs/ReleaseNotes.rst
  clang-tools-extra/docs/clang-tidy/checks/list.rst
  clang-tools-extra/docs/clang-tidy/checks/misc-dispatch-once-assignment.rst
  clang-tools-extra/docs/clang-tidy/checks/misc-dispatch-once-nonstatic.rst
  clang-tools-extra/test/clang-tidy/misc-dispatch-once-assignment.cpp
  clang-tools-extra/test/clang-tidy/misc-dispatch-once-nonstatic.mm

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