[PATCH] D133574: [C2x] reject type definitions in offsetof

[YingChi Long via Phabricator via cfe-commits]

inclyc updated this revision to Diff 459248.
inclyc added a comment.

Use RAII object to maintain the Parser state

> have you explored making a new DeclSpecContext and modifying isDefiningTypeSpecifierContext()? I think that would likely be a cleaner approach.

Emm, I've tried passing a DeclaratorContext into `ParseTypeName()`

  SourceLocation TypeLoc = Tok.getLocation();
  InBuiltInOffsetOfBaseRAIIObject InOffsetof(*this, true);
  TypeResult Ty = ParseTypeName(nullptr, /*Context=???*/); 

But defining a new DeclaratorContext I have to complete a bunch of `case`
statements.

  // Parser.h
  static bool isTypeSpecifier(DeclSpecContext DSC);
  static AllowDefiningTypeSpec isDefiningTypeSpecifierContext(DeclSpecContext DSC, bool IsCPlusPlus);
  static bool isOpaqueEnumDeclarationContext(DeclSpecContext DSC);
  /* ... */    

And I think it is somehow strange to determine these properties within
__builtin_offsetof()? I'm not sure if it is really appropriate to define a
special context for a built-in function. This place should only need to
forbidden definitions, right?


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D133574/new/

https://reviews.llvm.org/D133574

Files:
  clang/docs/ReleaseNotes.rst
  clang/include/clang/Basic/DiagnosticSemaKinds.td
  clang/include/clang/Parse/Parser.h
  clang/include/clang/Parse/RAIIObjectsForParser.h
  clang/include/clang/Sema/Sema.h
  clang/lib/Parse/ParseDeclCXX.cpp
  clang/lib/Parse/ParseExpr.cpp
  clang/lib/Sema/SemaDecl.cpp
  clang/test/Parser/declarators.c
  clang/test/Sema/offsetof.c

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