diff options
Diffstat (limited to 'src/runtime')
| -rw-r--r-- | src/runtime/hashmap.go | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/src/runtime/hashmap.go b/src/runtime/hashmap.go index e15926b05a..ab99d24c35 100644 --- a/src/runtime/hashmap.go +++ b/src/runtime/hashmap.go @@ -130,6 +130,9 @@ type hmap struct { // A bucket for a Go map. type bmap struct { + // tophash generally contains the top byte of the hash value + // for each key in this bucket. If tophash[0] < minTopHash, + // tophash[0] is a bucket evacuation state instead. tophash [bucketCnt]uint8 // Followed by bucketCnt keys and then bucketCnt values. // NOTE: packing all the keys together and then all the values together makes the @@ -1079,6 +1082,8 @@ func evacuate(t *maptype, h *hmap, oldbucket uintptr) { // Unlink the overflow buckets & clear key/value to help GC. if h.flags&oldIterator == 0 { b = (*bmap)(add(h.oldbuckets, oldbucket*uintptr(t.bucketsize))) + // Preserve b.tophash because the evacuation + // state is maintained there. memclr(add(unsafe.Pointer(b), dataOffset), uintptr(t.bucketsize)-dataOffset) } } |