Initial commit: Go 1.23 release state

test/fixedbugs/issue8048.go

@@ -0,0 +1,107 @@
+// run
+
+// Copyright 2014 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.
+
+// Issue 8048. Incorrect handling of liveness when walking stack
+// containing faulting frame.
+
+package main
+
+import "runtime"
+
+func main() {
+	test1()
+	test2()
+	test3()
+}
+
+func test1() {
+	// test1f will panic without its own defer.
+	// The runtime.GC checks that we can walk the stack
+	// at that point and not get confused.
+	// The recover lets test1 exit normally.
+	defer func() {
+		runtime.GC()
+		recover()
+	}()
+	test1f()
+}
+
+func test1f() {
+	// Because b == false, the if does not execute,
+	// so x == nil, so the println(*x) faults reading
+	// from nil. The compiler will lay out the code
+	// so that the if body occurs above the *x,
+	// so if the liveness info at the *x is used, it will
+	// find the liveness at the call to runtime.GC.
+	// It will think y is live, but y is uninitialized,
+	// and the runtime will crash detecting a bad slice.
+	// The runtime should see that there are no defers
+	// corresponding to this panicked frame and ignore
+	// the frame entirely.
+	var x *int
+	var b bool
+	if b {
+		y := make([]int, 1)
+		runtime.GC()
+		x = &y[0]
+	}
+	println(*x)
+}
+
+func test2() {
+	// Same as test1, but the fault happens in the function with the defer.
+	// The runtime should see the defer and garbage collect the frame
+	// as if the PC were immediately after the defer statement.
+	defer func() {
+		runtime.GC()
+		recover()
+	}()
+	var x *int
+	var b bool
+	if b {
+		y := make([]int, 1)
+		runtime.GC()
+		x = &y[0]
+	}
+	println(*x)
+}
+
+func test3() {
+	// Like test1 but avoid array index, which does not
+	// move to end of function on ARM.
+	defer func() {
+		runtime.GC()
+		recover()
+	}()
+	test3setup()
+	test3f()
+}
+
+func test3setup() {
+	var x uintptr
+	var b bool
+	b = true
+	if b {
+		y := uintptr(123)
+		runtime.GC()
+		x = y
+	}
+	runtime.GC()
+	globl = x
+}
+
+var globl uintptr
+
+func test3f() {
+	var x *int
+	var b bool
+	if b {
+		y := new(int)
+		runtime.GC()
+		x = y
+	}
+	println(*x)
+}