Initial commit: Go 1.23 release state

test/fixedbugs/issue15329.go

@@ -0,0 +1,79 @@
+// run
+
+// Copyright 2016 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.
+
+// Previously, cmd/compile would rewrite
+//
+//     check(unsafe.Pointer(testMeth(1).Pointer()), unsafe.Pointer(testMeth(2).Pointer()))
+//
+// to
+//
+//     var autotmp_1 uintptr = testMeth(1).Pointer()
+//     var autotmp_2 uintptr = testMeth(2).Pointer()
+//     check(unsafe.Pointer(autotmp_1), unsafe.Pointer(autotmp_2))
+//
+// However, that means autotmp_1 is the only reference to the int
+// variable containing the value "1", but it's not a pointer type,
+// so it was at risk of being garbage collected by the evaluation of
+// testMeth(2).Pointer(), even though package unsafe's documentation
+// says the original code was allowed.
+//
+// Now cmd/compile rewrites it to
+//
+//     var autotmp_1 unsafe.Pointer = unsafe.Pointer(testMeth(1).Pointer())
+//     var autotmp_2 unsafe.Pointer = unsafe.Pointer(testMeth(2).Pointer())
+//     check(autotmp_1, autotmp_2)
+//
+// to ensure the pointed-to variables are visible to the GC.
+
+package main
+
+import (
+	"fmt"
+	"reflect"
+	"runtime"
+	"unsafe"
+)
+
+func main() {
+	// Test all the different ways we can invoke reflect.Value.Pointer.
+
+	// Direct method invocation.
+	check(unsafe.Pointer(testMeth(1).Pointer()), unsafe.Pointer(testMeth(2).Pointer()))
+
+	// Invocation via method expression.
+	check(unsafe.Pointer(reflect.Value.Pointer(testMeth(1))), unsafe.Pointer(reflect.Value.Pointer(testMeth(2))))
+
+	// Invocation via interface.
+	check(unsafe.Pointer(testInter(1).Pointer()), unsafe.Pointer(testInter(2).Pointer()))
+
+	// Invocation via method value.
+	check(unsafe.Pointer(testFunc(1)()), unsafe.Pointer(testFunc(2)()))
+}
+
+func check(p, q unsafe.Pointer) {
+	a, b := *(*int)(p), *(*int)(q)
+	if a != 1 || b != 2 {
+		fmt.Printf("got %v, %v; expected 1, 2\n", a, b)
+	}
+}
+
+func testMeth(x int) reflect.Value {
+	// Force GC to run.
+	runtime.GC()
+	return reflect.ValueOf(&x)
+}
+
+type Pointerer interface {
+	Pointer() uintptr
+}
+
+func testInter(x int) Pointerer {
+	return testMeth(x)
+}
+
+func testFunc(x int) func() uintptr {
+	return testMeth(x).Pointer
+}