From 675058768ad167e84f9ec02dc21a357cb1fab047 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Henrik=20Grubbstr=C3=B6m=20=28Grubba=29?=
<grubba@grubba.org>
Date: Mon, 23 Jun 2014 16:28:44 +0200
Subject: [PATCH] Compiler: Improved cycle detection in implements() and
is_compatible().
Under some circumstances the new cache entries could be overwritten
before the functions had completed, leading to infinite recursion.
Fixes [InfoKOM 775534].
---
src/program.c | 28 +++++++++++++++++++++++-----
1 file changed, 23 insertions(+), 5 deletions(-)
diff --git a/src/program.c b/src/program.c
index 95e65e3be6..f62216bf7e 100644
--- a/src/program.c
+++ b/src/program.c
@@ -11697,8 +11697,14 @@ int find_child(struct program *parent, struct program *child)
/* returns 1 if a implements b */
static int low_implements(struct program *a, struct program *b)
{
+ DECLARE_CYCLIC();
int e;
+ int ret = 1;
struct pike_string *s=findstring("__INIT");
+
+ if (BEGIN_CYCLIC(a, b)) return 1; /* Tentatively ok, */
+ SET_CYCLIC_RET(1);
+
for(e=0;e<b->num_identifier_references;e++)
{
struct identifier *bid;
@@ -11714,7 +11720,8 @@ static int low_implements(struct program *a, struct program *b)
#if 0
fprintf(stderr, "Missing identifier \"%s\"\n", bid->name->str);
#endif /* 0 */
- return 0;
+ ret = 0;
+ break;
}
if (!pike_types_le(bid->type, ID_FROM_INT(a, i)->type)) {
@@ -11723,7 +11730,8 @@ static int low_implements(struct program *a, struct program *b)
fprintf(stderr, "Identifier \"%s\" is incompatible.\n",
bid->name->str);
#endif /* 0 */
- return 0;
+ ret = 0;
+ break;
} else {
#if 0
fprintf(stderr, "Identifier \"%s\" is not strictly compatible.\n",
@@ -11732,7 +11740,9 @@ static int low_implements(struct program *a, struct program *b)
}
}
}
- return 1;
+
+ END_CYCLIC();
+ return ret;
}
#define IMPLEMENTS_CACHE_SIZE 1024
@@ -11770,9 +11780,14 @@ PMOD_EXPORT int implements(struct program *a, struct program *b)
/* Returns 1 if a is compatible with b */
static int low_is_compatible(struct program *a, struct program *b)
{
+ DECLARE_CYCLIC();
int e;
+ int ret = 1;
struct pike_string *s=findstring("__INIT");
+ if (BEGIN_CYCLIC(a, b)) return 1;
+ SET_CYCLIC_RET(1);
+
/* Optimize the loop somewhat */
if (a->num_identifier_references < b->num_identifier_references) {
struct program *tmp = a;
@@ -11804,10 +11819,13 @@ static int low_is_compatible(struct program *a, struct program *b)
fprintf(stderr, "Identifier \"%s\" is incompatible.\n",
bid->name->str);
#endif /* 0 */
- return 0;
+ ret = 0;
+ break;
}
}
- return 1;
+
+ END_CYCLIC();
+ return ret;
}
static struct implements_cache_s is_compatible_cache[IMPLEMENTS_CACHE_SIZE];
--
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