cmd/compile: don't inline reflect.Value.UnsafeAddr/Pointer if enable checkptr

Fixes #35073

Change-Id: I4b555bbc33d39a97544e6dd9c61d95ae212f472b
Reviewed-on: https://go-review.googlesource.com/c/go/+/222878
Run-TryBot: Cuong Manh Le <cuong.manhle.vn@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>

src/cmd/compile/internal/gc/inl.go

@@ -575,6 +575,12 @@ func inlnode(n *Node, maxCost int32) *Node {
 	// so escape analysis can avoid more heapmoves.
 	case OCLOSURE:
 		return n
+	case OCALLMETH:
+		// Prevent inlining some reflect.Value methods when using checkptr,
+		// even when package reflect was compiled without it (#35073).
+		if s := n.Left.Sym; Debug_checkptr != 0 && s.Pkg.Path == "reflect" && (s.Name == "Value.UnsafeAddr" || s.Name == "Value.Pointer") {
+			return n
+		}
 	}
 
 	lno := setlineno(n)

test/fixedbugs/issue35073.go

@@ -0,0 +1,23 @@
+// run -gcflags=-d=checkptr
+
+// Copyright 2020 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.
+
+// Test that reflect.Value.UnsafeAddr/Pointer is handled
+// correctly by -d=checkptr
+
+package main
+
+import (
+	"reflect"
+	"unsafe"
+)
+
+func main() {
+	n := 10
+	m := make(map[string]string)
+
+	_ = unsafe.Pointer(reflect.ValueOf(&n).Elem().UnsafeAddr())
+	_ = unsafe.Pointer(reflect.ValueOf(&m).Elem().Pointer())
+}