runtime: eliminate heapBits.hasPointers
This is no longer necessary now that we can more efficiently consult
the span's noscan bit.
This is a cherry-pick of dev.garbage commit 312aa09996.
Change-Id: Id0b00b278533660973f45eb6efa5b00f373d58af
Reviewed-on: https://go-review.googlesource.com/41252
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rick Hudson <rlh@golang.org>
diff --git a/src/runtime/mbitmap.go b/src/runtime/mbitmap.go
index 844e662..48754de 100644
--- a/src/runtime/mbitmap.go
+++ b/src/runtime/mbitmap.go
@@ -495,17 +495,6 @@
return h.bits()&bitPointer != 0
}
-// hasPointers reports whether the given object has any pointers.
-// It must be told how large the object at h is for efficiency.
-// h must describe the initial word of the object.
-func (h heapBits) hasPointers(size uintptr) bool {
- // TODO: Use span.noScan instead of the heap bitmap.
- if size == sys.PtrSize { // 1-word objects are always pointers
- return true
- }
- return (*h.bitp>>h.shift)&bitScan != 0
-}
-
// isCheckmarked reports whether the heap bits have the checkmarked bit set.
// It must be told how large the object at h is, because the encoding of the
// checkmark bit varies by size.
diff --git a/src/runtime/mgcmark.go b/src/runtime/mgcmark.go
index 1046aa8..dbca5cd 100644
--- a/src/runtime/mgcmark.go
+++ b/src/runtime/mgcmark.go
@@ -1127,7 +1127,7 @@
// paths), in which case we must *not* enqueue
// oblets since their bitmaps will be
// uninitialized.
- if !hbits.hasPointers(n) {
+ if s.spanclass.noscan() {
// Bypass the whole scan.
gcw.bytesMarked += uint64(n)
return
@@ -1257,7 +1257,7 @@
atomic.Or8(mbits.bytep, mbits.mask)
// If this is a noscan object, fast-track it to black
// instead of greying it.
- if !hbits.hasPointers(span.elemsize) {
+ if span.spanclass.noscan() {
gcw.bytesMarked += uint64(span.elemsize)
return
}
