[PATCH] D63753: [Sema] Instead of rejecting C unions with non-trivial fields, detect attempts to destruct/initialize/copy them.

[Akira Hatanaka via Phabricator via cfe-commits]

ahatanak created this revision.
ahatanak added reviewers: rjmccall, rsmith.
ahatanak added a project: clang.
Herald added subscribers: dexonsmith, jkorous.

This patch diagnoses uses of non-trivial C unions in the following contexts:

- function parameters
- function returns
- variables with automatic storage duration
- assignment
- compound literal with automatic storage duration
- block capture except when a `__block` variable is captured by a non-escaping block

Note that we already reject non-trivial C structs/unions used for variable function arguments. Also this patch doesn't detect non-trivial C unions passed to functions without function prototypes. I think that's okay since clang will reject the function definition's parameters, but if it isn't okay, it's possible to add diagnostics for that too.

See the discussion in https://reviews.llvm.org/D62988 for more background.

rdar://problem/50679094


Repository:
  rC Clang

https://reviews.llvm.org/D63753

Files:
  include/clang/AST/Type.h
  include/clang/Basic/DiagnosticSemaKinds.td
  include/clang/Sema/Sema.h
  lib/AST/Type.cpp
  lib/Sema/Sema.cpp
  lib/Sema/SemaDecl.cpp
  lib/Sema/SemaExpr.cpp
  lib/Sema/SemaType.cpp
  test/CodeGenObjC/Inputs/strong_in_union.h
  test/CodeGenObjC/strong-in-c-struct.m
  test/SemaObjC/arc-decls.m
  test/SemaObjC/non-trivial-c-union.m

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