tccpp: Fix corner case

See added testcase 19.c from a bug report.  The problem is reading outside
the arguments buffers, even though we aren't allowed to.  The single
can_read_stream variable is not enough, sometimes we need to be able
to pop into outer contexts but not into arbitrarily outside contexts.

The trick is to terminate argument tokens with a EOF (and not just with
0 that makes us pop contexts), and deal with that in the few places
we have to,

This enables some cleanups of the can_read_stream variable use.

1 files changed, 13 insertions, 0 deletions

diff --git a/tests/pp/20.c b/tests/pp/20.c
new file mode 100644
index 0000000..7944d62
--- /dev/null
+++ b/tests/pp/20.c
@@ -0,0 +1,13 @@
+/* Various things I encountered while hacking the pre processor */
+#define wrap(x) x
+#define pr_warning(fmt, ...) printk(KERN_WARNING fmt, ##__VA_ARGS__)
+#define pr_warn(x,y) pr_warning(x,y)
+#define net_ratelimited_function(function, ...) function(__VA_ARGS__)
+X1 net_ratelimited_function(pr_warn, "pipapo", bla);
+X2 net_ratelimited_function(wrap(pr_warn), "bla", foo);
+#define two m n
+#define chain4(a,b,c,d) a ## b ## c ## d
+X2 chain4(two,o,p,q)
+X3 chain4(o,two,p,q)
+X4 chain4(o,p,two,q)
+X5 chain4(o,p,q,two)