Improve diagnostics if _Noreturn is placed after a function declarator. (This sometimes happens when a macro is used that expands to either the GNU noreturn attribute or _Noreturn.)

llvm-svn: 221630

1 files changed, 22 insertions, 1 deletions

diff --git a/clang/lib/Parse/ParseDecl.cpp b/clang/lib/Parse/ParseDecl.cpp
index b2fa88db2b6..66b98c2c4da 100644
--- a/clang/lib/Parse/ParseDecl.cpp
+++ b/clang/lib/Parse/ParseDecl.cpp
@@ -1601,9 +1601,30 @@ Parser::DeclGroupPtrTy Parser::ParseDeclGroup(ParsingDeclSpec &DS,
   // appropriate function scope after the function Decl has been constructed.
   // These will be parsed in ParseFunctionDefinition or ParseLexedAttrList.
   LateParsedAttrList LateParsedAttrs(true);
-  if (D.isFunctionDeclarator())
+  if (D.isFunctionDeclarator()) {
     MaybeParseGNUAttributes(D, &LateParsedAttrs);
 
+    // The _Noreturn keyword can't appear here, unlike the GNU noreturn
+    // attribute. If we find the keyword here, tell the user to put it
+    // at the start instead.
+    if (Tok.is(tok::kw__Noreturn)) {
+      SourceLocation Loc = ConsumeToken();
+      const char *PrevSpec;
+      unsigned DiagID;
+
+      // We can offer a fixit if it's valid to mark this function as _Noreturn
+      // and we don't have any other declarators in this declaration.
+      bool Fixit = !DS.setFunctionSpecNoreturn(Loc, PrevSpec, DiagID);
+      MaybeParseGNUAttributes(D, &LateParsedAttrs);
+      Fixit &= Tok.is(tok::semi) || Tok.is(tok::l_brace) || Tok.is(tok::kw_try);
+
+      Diag(Loc, diag::err_c11_noreturn_misplaced)
+          << (Fixit ? FixItHint::CreateRemoval(Loc) : FixItHint())
+          << (Fixit ? FixItHint::CreateInsertion(D.getLocStart(), "_Noreturn ")
+                    : FixItHint());
+    }
+  }
+
   // Check to see if we have a function *definition* which must have a body.
   if (D.isFunctionDeclarator() &&
       // Look at the next token to make sure that this isn't a function