cmd/compile: add support for unsafe.{String,StringData,SliceData}

For #53003

Change-Id: I13a761daca8b433b271a1feb711c103d9820772d
Reviewed-on: https://go-review.googlesource.com/c/go/+/423774
Reviewed-by: Heschi Kreinick <heschi@google.com>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: hopehook <hopehook@golangcn.org>
Reviewed-by: Cuong Manh Le <cuong.manhle.vn@gmail.com>
Reviewed-by: Keith Randall <khr@golang.org>
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>

1 files changed, 22 insertions, 0 deletions

diff --git a/test/unsafe_slice_data.go b/test/unsafe_slice_data.go
new file mode 100644
index 0000000000..e8b8207547
--- /dev/null
+++ b/test/unsafe_slice_data.go
@@ -0,0 +1,22 @@
+// run
+
+// Copyright 2022 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.
+
+package main
+
+import (
+	"fmt"
+	"reflect"
+	"unsafe"
+)
+
+func main() {
+	var s = []byte("abc")
+	sh1 := *(*reflect.SliceHeader)(unsafe.Pointer(&s))
+	ptr2 := unsafe.Pointer(unsafe.SliceData(s))
+	if ptr2 != unsafe.Pointer(sh1.Data) {
+		panic(fmt.Errorf("unsafe.SliceData %p != %p", ptr2, unsafe.Pointer(sh1.Data)))
+	}
+}