Looks like sparc64 broke for libgo when parallel garbage collection was
introduced. This patch is an attempt to get it working again.
Bootstrapped and ran Go testsuite on x86_64-unknown-linux-gnu, not that
that proves much. Committed to mainline.
Ian
diff -r b8ae4def7c14 libgo/runtime/lfstack.c
--- a/libgo/runtime/lfstack.c Thu Jan 24 11:43:43 2013 -0800
+++ b/libgo/runtime/lfstack.c Fri Jan 25 15:41:18 2013 -0800
@@ -15,6 +15,15 @@
# define PTR_BITS 32
#endif
#define PTR_MASK ((1ull<<PTR_BITS)-1)
+#define CNT_MASK (0ull-1)
+
+#if __SIZEOF_POINTER__ == 8 && defined(__sparc__)
+// SPARC64 uses all 64 bits of virtual addresses. Use low-order three
+bits as ABA counter.
+#define PTR_BITS 0
+#define CNT_MASK 7
+#define PTR_MASK ((0ull-1)<<3)
+#endif
void
runtime_lfstackpush(uint64 *head, LFNode *node)
@@ -27,7 +36,7 @@
}
node->pushcnt++;
- new = (uint64)(uintptr)node|(((uint64)node->pushcnt)<<PTR_BITS);
+ new = (uint64)(uintptr)node|(((uint64)node->pushcnt&CNT_MASK)<<PTR_BITS);
old = runtime_atomicload64(head);
for(;;) {
node->next = (LFNode*)(uintptr)(old&PTR_MASK);
@@ -50,7 +59,7 @@
node2 = runtime_atomicloadp(&node->next);
new = 0;
if(node2 != nil)
- new = (uint64)(uintptr)node2|(((uint64)node2->pushcnt)<<PTR_BITS);
+ new = (uint64)(uintptr)node2|(((uint64)node2->pushcnt&CNT_MASK)<<PTR_BITS);
if(runtime_cas64(head, &old, new))
return node;
}
