1 files changed, 58 insertions, 0 deletions
diff --git a/src/runtime/export_map_swiss_test.go b/src/runtime/export_map_swiss_test.go
new file mode 100644
index 0000000000..ac0308fce0
--- /dev/null
+++ b/src/runtime/export_map_swiss_test.go
@@ -0,0 +1,58 @@
+// Copyright 2024 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build goexperiment.swissmap
+
+package runtime
+
+import (
+	"internal/abi"
+	"unsafe"
+)
+
+func MapBucketsCount(m map[int]int) int {
+	h := *(**hmap)(unsafe.Pointer(&m))
+	return 1 << h.B
+}
+
+func MapBucketsPointerIsNil(m map[int]int) bool {
+	h := *(**hmap)(unsafe.Pointer(&m))
+	return h.buckets == nil
+}
+
+func MapTombstoneCheck(m map[int]int) {
+	// Make sure emptyOne and emptyRest are distributed correctly.
+	// We should have a series of filled and emptyOne cells, followed by
+	// a series of emptyRest cells.
+	h := *(**hmap)(unsafe.Pointer(&m))
+	i := any(m)
+	t := *(**maptype)(unsafe.Pointer(&i))
+
+	for x := 0; x < 1<<h.B; x++ {
+		b0 := (*bmap)(add(h.buckets, uintptr(x)*uintptr(t.BucketSize)))
+		n := 0
+		for b := b0; b != nil; b = b.overflow(t) {
+			for i := 0; i < abi.SwissMapBucketCount; i++ {
+				if b.tophash[i] != emptyRest {
+					n++
+				}
+			}
+		}
+		k := 0
+		for b := b0; b != nil; b = b.overflow(t) {
+			for i := 0; i < abi.SwissMapBucketCount; i++ {
+				if k < n && b.tophash[i] == emptyRest {
+					panic("early emptyRest")
+				}
+				if k >= n && b.tophash[i] != emptyRest {
+					panic("late non-emptyRest")
+				}
+				if k == n-1 && b.tophash[i] == emptyOne {
+					panic("last non-emptyRest entry is emptyOne")
+				}
+				k++
+			}
+		}
+	}
+}