"unsafe"
)
+// heapArenaPtrScalar contains the per-heapArena pointer/scalar metadata for the GC.
+type heapArenaPtrScalar struct {
+ // bitmap stores the pointer/scalar bitmap for the words in
+ // this arena. See mbitmap.go for a description.
+ // This array uses 1 bit per word of heap, or 1.6% of the heap size (for 64-bit).
+ bitmap [heapArenaBitmapWords]uintptr
+
+ // If the ith bit of noMorePtrs is true, then there are no more
+ // pointers for the object containing the word described by the
+ // high bit of bitmap[i].
+ // In that case, bitmap[i+1], ... must be zero until the start
+ // of the next object.
+ // We never operate on these entries using bit-parallel techniques,
+ // so it is ok if they are small. Also, they can't be bigger than
+ // uint16 because at that size a single noMorePtrs entry
+ // represents 8K of memory, the minimum size of a span. Any larger
+ // and we'd have to worry about concurrent updates.
+ // This array uses 1 bit per word of bitmap, or .024% of the heap size (for 64-bit).
+ noMorePtrs [heapArenaBitmapWords / 8]uint8
+}
+
// addb returns the byte pointer p+n.
//
//go:nowritebarrier