Re: [PATCH C] Fix pr44517

["Joseph S. Myers" <joseph@codesourcery.com>]

On Tue, 22 Jun 2010, Shujing Zhao wrote:

> Hi,
> 
> This patch tries to improve diagnostic for wrong type name in function
> declaration. It also changes the algorithm of function
> c_parser_parms_list_declarator. If one of parameter declaration is wrong,
> c_parser_parms_list_declarator would return NULL, not an empty parameter
> information struct. A test case is added to test this change.

You are changing the semantics of the variable good_parm from meaning 
"there was at least one good parameter" to "there were no bad parameters".  
Now, such a change should be accompanied by a change of name (e.g. to 
bad_parm, also reversing the sense of the variable).

There was a previous invariant that get_pending_sizes would be called 
after any parameters were parsed, either directly or via get_parm_info 
because good_parm would be set, and with this patch, this invariant is no 
longer maintained.  This is unsafe; you need to run this cleanup, whatever 
you then return from c_parser_parms_list_declarator.  Consider for example 
the testcase:

void foo(int n, int a[n], pid_t x);
void bar() {}

(related to gcc.dg/noncompile/pr35444-*.c).  With your patch, this 
testcase (which should be added to the next revision of the patch) gets an 
ICE, because you lost the call to get_pending_sizes via get_parm_info.

> +      error ("unknown type name %qE", token->value);

I don't think %qE is appropriate here if the token is not an identifier.

-- 
Joseph S. Myers
joseph@codesourcery.com