[hackers] [scc] [cc1] Add asserts in hash removals so that broken invariants are obvious || Michael Forney

From: <git_AT_suckless.org>
Date: Mon, 20 Feb 2017 04:41:35 +0100 (CET)

commit 4c2396d344274ea2c415858d89135e5e864e7673
Author: Michael Forney <mforney_AT_mforney.org>
AuthorDate: Sun Feb 19 13:58:10 2017 -0800
Commit: Roberto E. Vargas Caballero <k0ga_AT_shike2.com>
CommitDate: Mon Feb 20 04:40:24 2017 +0100

    [cc1] Add asserts in hash removals so that broken invariants are obvious
    
    It appears that these invariants aren't so invariant after all.

diff --git a/cc1/symbol.c b/cc1/symbol.c
index bdd26d6..1126279 100644
--- a/cc1/symbol.c
+++ b/cc1/symbol.c
_AT_@ -1,5 +1,6 @@
 /* See LICENSE file for copyright and license details. */
 static char sccsid[] = "_AT_(#) ./cc1/symbol.c";
+#include <assert.h>
 #include <limits.h>
 #include <stdio.h>
 #include <stdlib.h>
_AT_@ -72,6 +73,7 @@ unlinkhash(Symbol *sym)
         if ((sym->flags & SDECLARED) == 0)
                 return;
         h = hash(sym->name, sym->ns);
+ assert(*h == sym);
         *h = sym->hash;
 }
 
diff --git a/cc1/types.c b/cc1/types.c
index f9d6391..7abb58e 100644
--- a/cc1/types.c
+++ b/cc1/types.c
_AT_@ -1,5 +1,6 @@
 /* See LICENSE file for copyright and license details. */
 static char sccsid[] = "_AT_(#) ./cc1/types.c";
+#include <assert.h>
 #include <inttypes.h>
 #include <stdio.h>
 #include <stdlib.h>
_AT_@ -410,7 +411,7 @@ eqtype(Type *tp1, Type *tp2, int equiv)
 void
 flushtypes(void)
 {
- Type *tp, *next;
+ Type *tp, *next, **h;
 
         for (tp = localtypes; tp; tp = next) {
                 next = tp->next;
_AT_@ -423,7 +424,9 @@ flushtypes(void)
                          * we do know that tp is always the head
                          * of the collision list
                          */
- typetab[HASH(tp)] = tp->h_next;
+ h = &typetab[HASH(tp)];
+ assert(*h == tp);
+ *h = tp->h_next;
                 case STRUCT:
                 case UNION:
                 case ENUM:
Received on Mon Feb 20 2017 - 04:41:35 CET

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