tventi: work around gcc 4.3 bug (reported by Lucho Ionkov) - plan9port - [fork] Plan 9 from user space
HTML git clone git://src.adamsgaard.dk/plan9port
DIR Log
DIR Files
DIR Refs
DIR README
DIR LICENSE
---
DIR commit dce4cbabd1bbfa3a8acc05ae0b2c3a9df17f93d2
DIR parent 17b19538a48c036dbdc8817d233c0086f327485c
HTML Author: Russ Cox <rsc@swtch.com>
Date: Thu, 31 Jul 2008 15:41:54 -0400
venti: work around gcc 4.3 bug (reported by Lucho Ionkov)
Diffstat:
M src/cmd/venti/srv/icache.c | 14 +++++++++++++-
1 file changed, 13 insertions(+), 1 deletion(-)
---
DIR diff --git a/src/cmd/venti/srv/icache.c b/src/cmd/venti/srv/icache.c
t@@ -15,7 +15,19 @@ struct ICache
IHash *hash;
IEntry *entries;
int nentries;
- IEntry free;
+
+ /*
+ * gcc 4.3 inlines the pushfirst loop in initicache,
+ * but the inliner incorrectly deduces that
+ * icache.free.next has a constant value
+ * throughout the loop. (In fact, pushfirst
+ * assigns to it as ie->prev->next.)
+ * Marking it volatile should avoid this bug.
+ * The speed of linked list operations is dwarfed
+ * by the disk i/o anyway.
+ */
+ volatile IEntry free;
+
IEntry clean;
IEntry dirty;
u32int maxdirty;