package scan

import "internal/runtime/gc/scan"

Index ¶

• func ExpandReference(sizeClass int, packed *gc.ObjMask, unpacked *gc.PtrMask)
• func FilterNil(bufp *uintptr, n int32) int32
• func HasFastScanSpanPacked() bool
• func ScanSpanPacked(mem unsafe.Pointer, bufp *uintptr, objMarks *gc.ObjMask, sizeClass uintptr, ptrMask *gc.PtrMask) (count int32)
• func ScanSpanPackedGo(mem unsafe.Pointer, bufp *uintptr, objMarks *gc.ObjMask, sizeClass uintptr, ptrMask *gc.PtrMask) (count int32)
• func ScanSpanPackedReference(mem unsafe.Pointer, bufp *uintptr, objMarks *gc.ObjMask, sizeClass uintptr, ptrMask *gc.PtrMask) (count int32)

Functions ¶

func ExpandReference ¶

func ExpandReference(sizeClass int, packed *gc.ObjMask, unpacked *gc.PtrMask)

ExpandReference is a reference implementation of an expander function that translates object mark bits into a bitmap of one bit per word of marked object, assuming the object is of the provided size class.

func FilterNil ¶

func FilterNil(bufp *uintptr, n int32) int32

FilterNil packs non-nil (non-zero) values in bufp together at the beginning of bufp, returning the length of the packed buffer. It treats bufp as an array of size n.

func HasFastScanSpanPacked ¶

func HasFastScanSpanPacked() bool

func ScanSpanPacked ¶

func ScanSpanPacked(mem unsafe.Pointer, bufp *uintptr, objMarks *gc.ObjMask, sizeClass uintptr, ptrMask *gc.PtrMask) (count int32)

func ScanSpanPackedGo ¶

func ScanSpanPackedGo(mem unsafe.Pointer, bufp *uintptr, objMarks *gc.ObjMask, sizeClass uintptr, ptrMask *gc.PtrMask) (count int32)

ScanSpanPackedGo is an optimized pure Go implementation of ScanSpanPacked.

func ScanSpanPackedReference ¶

func ScanSpanPackedReference(mem unsafe.Pointer, bufp *uintptr, objMarks *gc.ObjMask, sizeClass uintptr, ptrMask *gc.PtrMask) (count int32)

ScanSpanPackedReference is the reference implementation of ScanScanPacked. It prioritizes clarity over performance.

Concretely, ScanScanPacked functions read pointers from mem, assumed to be gc.PageSize-aligned and gc.PageSize in size, and writes them to bufp, which is large enough to guarantee that even if pointer-word of mem is a pointer, it will fit. Therefore bufp, is always at least gc.PageSize in size.

ScanSpanPacked is supposed to identify pointers by first filtering words by objMarks, where each bit of the mask represents gc.SizeClassToSize[sizeClass] bytes of memory, and then filtering again by the bits in ptrMask.

Source Files ¶

expand_reference.go filter.go scan_generic.go scan_go.go scan_reference.go