7 files changed, 25 insertions, 28 deletions
diff --git a/src/runtime/cgocall.go b/src/runtime/cgocall.go
index 02c4cb3622..8e4b0dea65 100644
--- a/src/runtime/cgocall.go
+++ b/src/runtime/cgocall.go
@@ -583,11 +583,12 @@ func cgoCheckUnknownPointer(p unsafe.Pointer, msg string) (base, i uintptr) {
 			return
 		}
 
-		b, hbits, span, _ := heapBitsForObject(uintptr(p), 0, 0)
+		b, span, _ := findObject(uintptr(p), 0, 0)
 		base = b
 		if base == 0 {
 			return
 		}
+		hbits := heapBitsForAddr(base)
 		n := span.elemsize
 		for i = uintptr(0); i < n; i += sys.PtrSize {
 			if i != 1*sys.PtrSize && !hbits.morePointers() {
diff --git a/src/runtime/mbitmap.go b/src/runtime/mbitmap.go
index 5e3a0011d9..0893afb180 100644
--- a/src/runtime/mbitmap.go
+++ b/src/runtime/mbitmap.go
@@ -370,17 +370,17 @@ func heapBitsForSpan(base uintptr) (hbits heapBits) {
 	return heapBitsForAddr(base)
 }
 
-// heapBitsForObject returns the base address for the heap object
-// containing the address p, the heapBits for base,
-// the object's span, and of the index of the object in s.
-// If p does not point into a heap object,
-// return base == 0
-// otherwise return the base of the object.
+// findObject returns the base address for the heap object containing
+// the address p, the object's span, and the index of the object in s.
+// If p does not point into a heap object, it returns base == 0.
+//
+// If p points is an invalid heap pointer and debug.invalidptr != 0,
+// findObject panics.
 //
 // refBase and refOff optionally give the base address of the object
 // in which the pointer p was found and the byte offset at which it
 // was found. These are used for error reporting.
-func heapBitsForObject(p, refBase, refOff uintptr) (base uintptr, hbits heapBits, s *mspan, objIndex uintptr) {
+func findObject(p, refBase, refOff uintptr) (base uintptr, s *mspan, objIndex uintptr) {
 	arenaStart := mheap_.arena_start
 	if p < arenaStart || p >= mheap_.arena_used {
 		return
@@ -444,8 +444,6 @@ func heapBitsForObject(p, refBase, refOff uintptr) (base uintptr, hbits heapBits
 			base += objIndex * s.elemsize
 		}
 	}
-	// Now that we know the actual base, compute heapBits to return to caller.
-	hbits = heapBitsForAddr(base)
 	return
 }
 
@@ -1852,7 +1850,8 @@ func getgcmask(ep interface{}) (mask []byte) {
 	}
 
 	// heap
-	if base, hbits, s, _ := heapBitsForObject(uintptr(p), 0, 0); base != 0 {
+	if base, s, _ := findObject(uintptr(p), 0, 0); base != 0 {
+		hbits := heapBitsForAddr(base)
 		n := s.elemsize
 		mask = make([]byte, n/sys.PtrSize)
 		for i := uintptr(0); i < n; i += sys.PtrSize {
diff --git a/src/runtime/mfinal.go b/src/runtime/mfinal.go
index e7ca5d669f..4ded18a345 100644
--- a/src/runtime/mfinal.go
+++ b/src/runtime/mfinal.go
@@ -326,7 +326,7 @@ func SetFinalizer(obj interface{}, finalizer interface{}) {
 	}
 
 	// find the containing object
-	base, _, _, _ := heapBitsForObject(uintptr(e.data), 0, 0)
+	base, _, _ := findObject(uintptr(e.data), 0, 0)
 
 	if base == 0 {
 		// 0-length objects are okay.
diff --git a/src/runtime/mgcmark.go b/src/runtime/mgcmark.go
index 5664390eae..b6bc689c1f 100644
--- a/src/runtime/mgcmark.go
+++ b/src/runtime/mgcmark.go
@@ -1100,8 +1100,8 @@ func scanblock(b0, n0 uintptr, ptrmask *uint8, gcw *gcWork) {
 				// Same work as in scanobject; see comments there.
 				obj := *(*uintptr)(unsafe.Pointer(b + i))
 				if obj != 0 && arena_start <= obj && obj < arena_used {
-					if obj, hbits, span, objIndex := heapBitsForObject(obj, b, i); obj != 0 {
-						greyobject(obj, b, i, hbits, span, gcw, objIndex)
+					if obj, span, objIndex := findObject(obj, b, i); obj != 0 {
+						greyobject(obj, b, i, span, gcw, objIndex)
 					}
 				}
 			}
@@ -1206,8 +1206,8 @@ func scanobject(b uintptr, gcw *gcWork) {
 		// Check if it points into heap and not back at the current object.
 		if obj != 0 && arena_start <= obj && obj < arena_used && obj-b >= n {
 			// Mark the object.
-			if obj, hbits, span, objIndex := heapBitsForObject(obj, b, i); obj != 0 {
-				greyobject(obj, b, i, hbits, span, gcw, objIndex)
+			if obj, span, objIndex := findObject(obj, b, i); obj != 0 {
+				greyobject(obj, b, i, span, gcw, objIndex)
 			}
 		}
 	}
@@ -1220,9 +1220,9 @@ func scanobject(b uintptr, gcw *gcWork) {
 // Preemption must be disabled.
 //go:nowritebarrier
 func shade(b uintptr) {
-	if obj, hbits, span, objIndex := heapBitsForObject(b, 0, 0); obj != 0 {
+	if obj, span, objIndex := findObject(b, 0, 0); obj != 0 {
 		gcw := &getg().m.p.ptr().gcw
-		greyobject(obj, 0, 0, hbits, span, gcw, objIndex)
+		greyobject(obj, 0, 0, span, gcw, objIndex)
 		if gcphase == _GCmarktermination || gcBlackenPromptly {
 			// Ps aren't allowed to cache work during mark
 			// termination.
@@ -1238,7 +1238,7 @@ func shade(b uintptr) {
 // See also wbBufFlush1, which partially duplicates this logic.
 //
 //go:nowritebarrierrec
-func greyobject(obj, base, off uintptr, hbits heapBits, span *mspan, gcw *gcWork, objIndex uintptr) {
+func greyobject(obj, base, off uintptr, span *mspan, gcw *gcWork, objIndex uintptr) {
 	// obj should be start of allocation, and so must be at least pointer-aligned.
 	if obj&(sys.PtrSize-1) != 0 {
 		throw("greyobject: obj not pointer-aligned")
@@ -1260,6 +1260,7 @@ func greyobject(obj, base, off uintptr, hbits heapBits, span *mspan, gcw *gcWork
 			getg().m.traceback = 2
 			throw("checkmark found unmarked object")
 		}
+		hbits := heapBitsForAddr(obj)
 		if hbits.isCheckmarked(span.elemsize) {
 			return
 		}
@@ -1386,9 +1387,9 @@ func gcMarkTinyAllocs() {
 		if c == nil || c.tiny == 0 {
 			continue
 		}
-		_, hbits, span, objIndex := heapBitsForObject(c.tiny, 0, 0)
+		_, span, objIndex := findObject(c.tiny, 0, 0)
 		gcw := &p.gcw
-		greyobject(c.tiny, 0, 0, hbits, span, gcw, objIndex)
+		greyobject(c.tiny, 0, 0, span, gcw, objIndex)
 		if gcBlackenPromptly {
 			gcw.dispose()
 		}
diff --git a/src/runtime/mheap.go b/src/runtime/mheap.go
index 46f57d272e..635e862324 100644
--- a/src/runtime/mheap.go
+++ b/src/runtime/mheap.go
@@ -1410,7 +1410,7 @@ func addfinalizer(p unsafe.Pointer, f *funcval, nret uintptr, fint *_type, ot *p
 		// situation where it's possible that markrootSpans
 		// has already run but mark termination hasn't yet.
 		if gcphase != _GCoff {
-			base, _, _, _ := heapBitsForObject(uintptr(p), 0, 0)
+			base, _, _ := findObject(uintptr(p), 0, 0)
 			mp := acquirem()
 			gcw := &mp.p.ptr().gcw
 			// Mark everything reachable from the object
diff --git a/src/runtime/mwbbuf.go b/src/runtime/mwbbuf.go
index c5619ed3fb..13b161ebde 100644
--- a/src/runtime/mwbbuf.go
+++ b/src/runtime/mwbbuf.go
@@ -243,11 +243,7 @@ func wbBufFlush1(_p_ *p) {
 			// path to reduce the rate of flushes?
 			continue
 		}
-		// TODO: This doesn't use hbits, so calling
-		// heapBitsForObject seems a little silly. We could
-		// easily separate this out since heapBitsForObject
-		// just calls heapBitsForAddr(obj) to get hbits.
-		obj, _, span, objIndex := heapBitsForObject(ptr, 0, 0)
+		obj, span, objIndex := findObject(ptr, 0, 0)
 		if obj == 0 {
 			continue
 		}
diff --git a/src/runtime/race.go b/src/runtime/race.go
index 1d35d2b641..09a8356770 100644
--- a/src/runtime/race.go
+++ b/src/runtime/race.go
@@ -187,7 +187,7 @@ type symbolizeDataContext struct {
 }
 
 func raceSymbolizeData(ctx *symbolizeDataContext) {
-	if base, _, span, _ := heapBitsForObject(ctx.addr, 0, 0); base != 0 {
+	if base, span, _ := findObject(ctx.addr, 0, 0); base != 0 {
 		ctx.heap = 1
 		ctx.start = base
 		ctx.size = span.elemsize