On Tue, Mar 20, 2007 at 11:04:16AM -0600, Kevin Handy wrote:
> >#define LANG_TREE_CODE(NODE) (TREE_CODE (NODE) == LANG_CODE ?
> >((tree_with_subcode *)(NODE))->subcode : TREE_CODE (NODE))
> >
> This subcode idea feels like a bug attractor to me.
>
> For example: #defines have enough problems with
> side effects, and this references NODE twice, so
> what happens when NODE is a function of some
> kind, or has other side effects?
Just look quickly at tree.h, there are plenty of other macros already
that evaluate their arguments multiple times.
> >switch contains >= 256 FE specific subcodes you'd use LANG_TREE_CODE
> >instead of TREE_CODE. GCC would warn you if you forget to use
> >LANG_TREE_CODE even when it is needed, at least in switches, you'd get
> >warning: case label value exceeds maximum value for type
> >
> I'd expect that the TREE_CODE would be referenced
> more often in comparisons, than in switch statements.
> These probably wouldn't generate the warning.
That warns too, see (-Wall):
enum foo
{
A=0,
B=1,
C=2,
X=254,
Y=255
};
struct tree
{
enum foo code : 8;
};
extern void bar (void);
void foo (struct tree *t)
{
switch (t->code)
{
case C:
break;
case 512:
bar ();
break;
case 1081:
break;
}
if (t->code == 1024)
bar ();
if (t->code != 1035)
bar ();
}
Jakub
