runtime: add tests for checkptr

We had a few test cases to make sure checkptr didn't have certain
false positives, but none to test for any true positives. This CL
fixes that.

Updates #22218.

Change-Id: I24c02e469a4af43b1748829a9df325ce510f7cc4
Reviewed-on: https://go-review.googlesource.com/c/go/+/214238
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Austin Clements <austin@google.com>

1 files changed, 36 insertions, 0 deletions

diff --git a/src/runtime/testdata/testprog/checkptr.go b/src/runtime/testdata/testprog/checkptr.go
new file mode 100644
index 0000000000..177db38e5a
--- /dev/null
+++ b/src/runtime/testdata/testprog/checkptr.go
@@ -0,0 +1,36 @@
+// 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.
+
+package main
+
+import "unsafe"
+
+func init() {
+	register("CheckPtrAlignment", CheckPtrAlignment)
+	register("CheckPtrArithmetic", CheckPtrArithmetic)
+	register("CheckPtrSize", CheckPtrSize)
+	register("CheckPtrSmall", CheckPtrSmall)
+}
+
+func CheckPtrAlignment() {
+	var x [2]int64
+	p := unsafe.Pointer(&x[0])
+	sink2 = (*int64)(unsafe.Pointer(uintptr(p) + 1))
+}
+
+func CheckPtrArithmetic() {
+	var x int
+	i := uintptr(unsafe.Pointer(&x))
+	sink2 = (*int)(unsafe.Pointer(i))
+}
+
+func CheckPtrSize() {
+	p := new(int64)
+	sink2 = p
+	sink2 = (*[100]int64)(unsafe.Pointer(p))
+}
+
+func CheckPtrSmall() {
+	sink2 = unsafe.Pointer(uintptr(1))
+}