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

[YingChi Long via Phabricator via cfe-commits]

inclyc updated this revision to Diff 462680.
inclyc added a comment.

Address comments.

Clang will now consider __builtin_offsetof #defined from "offsetof" to improve
diagnostic message.

For example:

  #define offsetof(t, d) __builtin_offsetof(t, d)
  
  int main() {
    return offsetof(struct S { int a; }, a);
  }



  local/offsetof.c:4:26: error: 'S' cannot be defined in 'offsetof'
    return offsetof(struct S { int a; }, a);
                           ^
  1 error generated.

Emm, the "expected-error" of struct B within a macro seems have to be annotated
at the same line as"struct A".

  int macro(void) {
    return offsetof(struct A // expected-error{{'A' cannot be defined in 'offsetof'}}
                             // expected-error at -1{{'B' cannot be defined in 'offsetof'}}     <---- Have to write this here, but I believe the line number is correct
    { 
      int a;
      struct B // FIXME: verifier seems to think the error is emitted by the macro
               // In fact the location of the error is "B" on the line above
      {
        int c;
        int d;
      } x;
    }, a);
  }



  clang/test/C/C2x/n2350.c:11:36: error: 'A' cannot be defined in '__builtin_offsetof'
    return __builtin_offsetof(struct A // expected-error{{'A' cannot be defined in '__builtin_offsetof'}} 
                                     ^
  clang/test/C/C2x/n2350.c:14:12: error: 'B' cannot be defined in '__builtin_offsetof'
      struct B // expected-error{{'B' cannot be defined in '__builtin_offsetof'}} 
             ^
  clang/test/C/C2x/n2350.c:26:26: error: 'A' cannot be defined in 'offsetof'
    return offsetof(struct A // expected-error{{'A' cannot be defined in 'offsetof'}}
                           ^
  clang/test/C/C2x/n2350.c:30:12: error: 'B' cannot be defined in 'offsetof' <-- note that this line number is "30" (not "26")
      struct B // FIXME: verifier seems to think the error is emitted by the macro
             ^
  4 errors generated.


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/ParseDecl.cpp
  clang/lib/Parse/ParseDeclCXX.cpp
  clang/lib/Parse/ParseExpr.cpp
  clang/lib/Sema/SemaDecl.cpp
  clang/lib/Sema/SemaDeclCXX.cpp
  clang/lib/Sema/SemaTemplate.cpp
  clang/test/C/C2x/n2350.c
  clang/test/Parser/declarators.c
  clang/test/SemaCXX/offsetof.cpp

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