Re: [Tinycc-devel] struct member/typedefs share namespace?

[Dave Dodge]

On Tue, Apr 18, 2006 at 10:00:54AM -0400, Toby Thain wrote:
> But then maybe my fix wasn't exactly the same as your workaround.  
> Starting from version 0.9.22 (Gentoo ebuild), at line 6639 (!) of  
> tcc.c, in parse_btype() after the default: label, I changed
>       if(typespec_found)
> to
>       if(type_found||typespec_found)

The patch below from January 2005 probably fixes it as well.

                                                  -Dave Dodge

-------------------------------------

tcc 0.9.22 doesn't properly handle the following construct:

  typedef [...] a;
  typedef [...] b;

  [...] foo([...])
  {
    a b; /* not parsed correctly */
  }

The problem is that it parses both "a" and "b" as typedef names, and
does nothing as a result.  Although the C99 grammar allows this
parsing, there is a constraint in the narrative that invalidates it
and requires "b" to be treated as a declarator.  This patch causes tcc
to stop looking for typedef names in a declaration specifier list
after it finds the first one; the end result should be that "b"
becomes a local variable and hides the "b" typedef while in scope.

--- tcc-0.9.22/tcc.c    2004-11-08 15:47:16.000000000 -0500
+++ tcc-0.9.22-patched/tcc.c    2005-01-24 23:08:04.000000000 -0500
@@ -6497,13 +6497,14 @@
  */
 static int parse_btype(CType *type, AttributeDef *ad)
 {
-    int t, u, type_found, typespec_found;
+    int t, u, type_found, typespec_found, typedef_found;
     Sym *s;
     CType type1;
 
     memset(ad, 0, sizeof(AttributeDef));
     type_found = 0;
     typespec_found = 0;
+    typedef_found = 0;
     t = 0;
     while(1) {
         switch(tok) {
@@ -6638,9 +6639,15 @@
         default:
             if (typespec_found)
                 goto the_end;
+            if (typedef_found)
+                /* we've already found a typedef-name in the declaration */
+                /* specifier list, so ignore any further ones and treat */
+                /* them as plain identifiers */
+                goto the_end;
             s = sym_find(tok);
             if (!s || !(s->type.t & VT_TYPEDEF))
                 goto the_end;
+            typedef_found = 1;
             t |= (s->type.t & ~VT_TYPEDEF);
             type->ref = s->type.ref;
             next();