[PATCH] D148105: [clang] Fix FIXME in isAlignasAttribute()

[Richard Sandiford via Phabricator via cfe-commits]

rsandifo-arm created this revision.
rsandifo-arm added reviewers: erichkeane, aaron.ballman.
Herald added a project: All.
rsandifo-arm requested review of this revision.
Herald added a project: clang.
Herald added a subscriber: cfe-commits.

AttributeCommonInfo::isAlignasAttribute() was used in one place:
isCXX11Attribute().  The intention was for isAlignasAttribute()
to return true for the C++ alignas keyword.  However, as a FIXME
noted, the function also returned true for the C _Alignas keyword.
This meant that isCXX11Attribute() returned true for _Alignas as
well as for alignas.

AttributeCommonInfos are now always constructed with an
AttributeCommonInfo::Form.  We can use that Form to convey whether
a keyword is alignas or not.

The patch uses 1 bit of an 8-bit hole in the current layout
of AttributeCommonInfo.  This might not be the best long-term design,
but it should be easy to adapt the layout if necessary (that is,
if other uses are found for the spare bits).

I don't know of a way of testing this (other than grep -c FIXME)


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D148105

Files:
  clang/include/clang/Basic/AttributeCommonInfo.h
  clang/lib/Sema/SemaType.cpp
  clang/lib/Serialization/ASTReaderDecl.cpp
  clang/utils/TableGen/ClangAttrEmitter.cpp

-------------- next part --------------
A non-text attachment was scrubbed...
Name: D148105.512741.patch
Type: text/x-patch
Size: 8447 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/cfe-commits/attachments/20230412/97c00342/attachment.bin>