[PATCH] D64600: [ObjC] Add an attribute that "clamps" signed char BOOLs to {0,1}

[Erik Pilkington via Phabricator via cfe-commits]

erik.pilkington created this revision.
erik.pilkington added reviewers: rjmccall, aaron.ballman, steven_wu.
Herald added subscribers: dexonsmith, jkorous.
Herald added a project: clang.

This attribute can be applied to typedefs of BOOL in Objective-C. It causes loads, stores, and casts to BOOL to clamp into {0,1}. This is useful for us because a lot of code is going to be moving from a platform where BOOL is a typedef for a native bool type (iOS) to a platform where its a typedef for signed char (macOS) because of macCatalyst. We can't change the type of the BOOL, since its ABI.

rdar://6510042

Thanks for taking a look!
Erik


Repository:
  rC Clang

https://reviews.llvm.org/D64600

Files:
  clang/include/clang/Basic/Attr.td
  clang/include/clang/Basic/AttrDocs.td
  clang/include/clang/Basic/DiagnosticSemaKinds.td
  clang/lib/AST/TypePrinter.cpp
  clang/lib/CodeGen/CGExpr.cpp
  clang/lib/CodeGen/CGExprScalar.cpp
  clang/lib/CodeGen/CodeGenFunction.h
  clang/lib/Sema/SemaType.cpp
  clang/test/CodeGenObjC/objc-clamping-bool.m
  clang/test/Misc/pragma-attribute-supported-attributes-list.test
  clang/test/SemaObjC/objc-clamping-bool.m

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