Robustify mpers.awk against input containing index loops

Make mpers.awk check for potential index loops.  Such loops should not
normally happen, but mpers.awk will not go into infinite recursion if
they do.

* mpers.awk (enter, leave): New functions.
(what_is): Use them.

diff --git a/mpers.awk b/mpers.awk
index f511acff37d223e63913aa0e89c86db16e818a2d..4c2def2fb2b417d0ceb96425a00e96f58114d245 100644 (file)
--- a/mpers.awk
+++ b/mpers.awk
@@ -15,9 +15,26 @@ function array_get(array_idx, array_member, array_return)
        }
        return array_return
 }
+function enter(array_idx)
+{
+       if (called[array_idx]) {
+               printf("%s: index loop detected:", FILENAME) > "/dev/stderr"
+               for (item in called)
+                       printf(" %s", item) > "/dev/stderr"
+               print "" > "/dev/stderr"
+               exit 1
+       }
+       called[array_idx] = 1
+}
+function leave(array_idx, to_return)
+{
+       delete called[array_idx]
+       return to_return
+}
 function what_is(what_idx, type_idx, special, item, \
                 location, prev_location, prev_returned_size)
 {
+       enter(what_idx)
        special = array_get(what_idx, "special")
        switch (special) {
        case "base_type":
@@ -52,7 +69,7 @@ function what_is(what_idx, type_idx, special, item, \
                returned_size = to_return * returned_size
                if ("" == to_return)
                        to_return = "00"
-               return to_return
+               return leave(what_idx, to_return)
                break
        case "structure_type":
                print "struct {"
@@ -107,18 +124,18 @@ function what_is(what_idx, type_idx, special, item, \
                break
        case "typedef":
                type_idx = array_get(what_idx, "type")
-               return what_is(type_idx)
+               return leave(what_idx, what_is(type_idx))
                break
        case "member":
                type_idx = array_get(what_idx, "type")
-               return what_is(type_idx)
+               return leave(what_idx, what_is(type_idx))
                break
        default:
                type_idx = array_get(what_idx, "type")
                what_is(type_idx)
                break
        }
-       return 0
+       return leave(what_idx, 0)
 }
 BEGIN {
        print "#include <inttypes.h>"