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[dev.garbage] runtime: eliminate heapBits.hasPointers

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This is no longer necessary now that we can more efficiently consult
the span's noscan bit.

Change-Id: Id0b00b278533660973f45eb6efa5b00f373d58af
Reviewed-on: https://go-review.googlesource.com/23701
Reviewed-by: Rick Hudson <rlh@golang.org>
This commit is contained in:
Austin Clements 2016-06-02 11:07:41 -04:00
parent d491e550c3
commit 312aa09996
2 changed files with 1 additions and 12 deletions
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11
src/runtime/mbitmap.go
View File

@ -505,17 +505,6 @@ func (h heapBits) isPointer() bool {
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)&bitMarked != 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.

2
src/runtime/mgcmark.go
View File

@ -1227,7 +1227,7 @@ func greyobject(obj, base, off uintptr, hbits heapBits, span *mspan, gcw *gcWork
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
}