Re: Sparse crash when mixing int and enum in ternary operator

[Kamil Dudka <kdudka@redhat.com>]

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On Tue March 9 2010 06:43:09 Christopher Li wrote:
> On Mon, Mar 8, 2010 at 5:24 PM, Pavel Roskin <proski@gnu.org> wrote:
> > Hello!
> > 
> > Sparse crashed when checking drivers/net/wireless/ath/ath9k/gpio.c in
> > Linux.  I could reduce the crash to the following simple program:
> > 
> > enum kind {
> >    GOOD
> > };
> > static void foo(enum kind k)
> > {
> > }
> > static void bar(int ok, int k)
> > {
> >    foo(ok ? GOOD : k);
> > }
> 
> Confirm. This is cause by the recent enum-warning patch. Without it the
> sparse runs fine.

Thank both of you for tacking down the bug!

> Let me see if this is some thing easy to fix.

It's easy to fix as soon as I understand how EXPR_CONDITIONAL/EXPR_SELECT
work in sparse.  A fix from scratch is attached, but I'll need more time
for testing it and to write some extra test-cases.

Kamil

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diff --git a/evaluate.c b/evaluate.c
index d3d5e6f..214b2b7 100644
--- a/evaluate.c
+++ b/evaluate.c
@@ -327,13 +327,28 @@ warn_for_int_to_enum_conversion (struct expression *expr, struct symbol *typeb)
 }
 
 static void
-warn_for_enum_conversions(struct expression *expr, struct symbol *type)
+do_warn_for_enum_conversions(struct expression *expr, struct symbol *type)
 {
 	warn_for_different_enum_types (expr, type);
 	warn_for_enum_to_int_conversion (expr, type);
 	warn_for_int_to_enum_conversion (expr, type);
 }
 
+static void
+warn_for_enum_conversions(struct expression *expr, struct symbol *type)
+{
+	switch (expr->type) {
+		case EXPR_CONDITIONAL:
+		case EXPR_SELECT:
+			do_warn_for_enum_conversions(expr->cond_true, type);
+			do_warn_for_enum_conversions(expr->cond_false, type);
+			break;
+
+		default:
+			do_warn_for_enum_conversions(expr, type);
+	}
+}
+
 /*
  * This gets called for implicit casts in assignments and
  * integer promotion. We often want to try to move the