diff options
Diffstat (limited to 'src/runtime/slice.go')
| -rw-r--r-- | src/runtime/slice.go | 12 |
1 files changed, 5 insertions, 7 deletions
diff --git a/src/runtime/slice.go b/src/runtime/slice.go index fd5d08b52c..4206f4384a 100644 --- a/src/runtime/slice.go +++ b/src/runtime/slice.go @@ -195,21 +195,19 @@ func growslice(et *_type, old slice, cap int) slice { var p unsafe.Pointer if et.kind&kindNoPointers != 0 { p = mallocgc(capmem, nil, false) - memmove(p, old.array, lenmem) // The append() that calls growslice is going to overwrite from old.len to cap (which will be the new length). // Only clear the part that will not be overwritten. memclrNoHeapPointers(add(p, newlenmem), capmem-newlenmem) } else { // Note: can't use rawmem (which avoids zeroing of memory), because then GC can scan uninitialized memory. p = mallocgc(capmem, et, true) - if !writeBarrier.enabled { - memmove(p, old.array, lenmem) - } else { - for i := uintptr(0); i < lenmem; i += et.size { - typedmemmove(et, add(p, i), add(old.array, i)) - } + if writeBarrier.enabled { + // Only shade the pointers in old.array since we know the destination slice p + // only contains nil pointers because it has been cleared during alloc. + bulkBarrierPreWriteSrcOnly(uintptr(p), uintptr(old.array), lenmem) } } + memmove(p, old.array, lenmem) return slice{p, old.len, newcap} } |