On Mon, 14 Sep 2020, Marek Polacek via Gcc-patches wrote:
> so I followed suit. In the C++ FE this was rather easy, because
> finish_parenthesized_expr already set TREE_NO_WARNING. In the C FE
> it was trickier; I've added a NOP_EXPR to discern between the non-()
> and () versions.
This sort of thing is normally handled for C via original_code in c_expr.
I suppose that doesn't work in this case because the code dealing with
parenthesized expressions has a special case for sizeof:
if (expr.original_code != C_MAYBE_CONST_EXPR
&& expr.original_code != SIZEOF_EXPR)
expr.original_code = ERROR_MARK;
Handling this in some way via c_expr seems better to me than generating
NOP_EXPR. I suppose you could invent a PAREN_SIZEOF_EXPR used by (sizeof
foo) and ((sizeof foo)) etc. as an original_code setting (and handled the
same as SIZEOF_EXPR by whatever other warnings look for SIZEOF_EXPR
there), or else add fields to c_expr to allow more such information to be
tracked there.
--
Joseph S. Myers
jos...@codesourcery.com
