[PING^2] [C/C++] PR c/4076 -Wunused doesn't warn about static function only called by itself

[Manuel López-Ibáñez]

On 19/03/07, Nathan Sidwell <nathan@codesourcery.com> wrote:
> Manuel López-Ibáñez wrote:
>
> > I can copy the condition. Much better, I can put it inside mark_used
> > so we don't have to duplicate it everywhere.
>
> that seems a much better approach :)
>

Bad news. It produces ICE in:
libstdc++-v3/src/pool_allocator.cc:112: internal compiler error: in
build_call_a, at cp/call.c:325

 if (TREE_CODE (function) == ADDR_EXPR
      && TREE_CODE (TREE_OPERAND (function, 0)) == FUNCTION_DECL)
    {
      decl = TREE_OPERAND (function, 0);
      if (!TREE_USED (decl))
        {
          /* We invoke build_call directly for several library
             functions.  These may have been declared normally if
             we're building libgcc, so we can't just check
             DECL_ARTIFICIAL.  */
          gcc_assert (DECL_ARTIFICIAL (decl)
                      || !strncmp (IDENTIFIER_POINTER (DECL_NAME (decl)),
                                   "__", 2));
          mark_used (decl);
        }
    }

DECL_ARTIFICIAL is false and IDENTIFIER_POINTER (DECL_NAME (decl)) is
"_M_allocate_chunk"

Any ideas?


> > It seems that check_global_declarations, which is the one that emits
> > the Wunused-function warnings, is not called for functions in an
> > anonymous namespace. I tried finding where the decision is made
> > without any success. Any ideas?
>
> sorry, nothing comes to mind.  It is an orthogonal issue though, IMHO.
>

So what is the point in making my patch to worry about functions in
anonymous namespaces if anyway they are not equivalent to static with
respect to TREE_USED ? That is, no matter what my patch does, the
warning is not going to be emitted.

Cheers,
Manuel.