1 files changed, 440 insertions, 0 deletions
diff --git a/src/runtime/defer_test.go b/src/runtime/defer_test.go
new file mode 100644
index 0000000..9a40ea1
--- /dev/null
+++ b/src/runtime/defer_test.go
@@ -0,0 +1,440 @@
+// Copyright 2019 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 runtime_test
+
+import (
+	"fmt"
+	"reflect"
+	"runtime"
+	"testing"
+)
+
+// Make sure open-coded defer exit code is not lost, even when there is an
+// unconditional panic (hence no return from the function)
+func TestUnconditionalPanic(t *testing.T) {
+	defer func() {
+		if recover() != "testUnconditional" {
+			t.Fatal("expected unconditional panic")
+		}
+	}()
+	panic("testUnconditional")
+}
+
+var glob int = 3
+
+// Test an open-coded defer and non-open-coded defer - make sure both defers run
+// and call recover()
+func TestOpenAndNonOpenDefers(t *testing.T) {
+	for {
+		// Non-open defer because in a loop
+		defer func(n int) {
+			if recover() != "testNonOpenDefer" {
+				t.Fatal("expected testNonOpen panic")
+			}
+		}(3)
+		if glob > 2 {
+			break
+		}
+	}
+	testOpen(t, 47)
+	panic("testNonOpenDefer")
+}
+
+//go:noinline
+func testOpen(t *testing.T, arg int) {
+	defer func(n int) {
+		if recover() != "testOpenDefer" {
+			t.Fatal("expected testOpen panic")
+		}
+	}(4)
+	if arg > 2 {
+		panic("testOpenDefer")
+	}
+}
+
+// Test a non-open-coded defer and an open-coded defer - make sure both defers run
+// and call recover()
+func TestNonOpenAndOpenDefers(t *testing.T) {
+	testOpen(t, 47)
+	for {
+		// Non-open defer because in a loop
+		defer func(n int) {
+			if recover() != "testNonOpenDefer" {
+				t.Fatal("expected testNonOpen panic")
+			}
+		}(3)
+		if glob > 2 {
+			break
+		}
+	}
+	panic("testNonOpenDefer")
+}
+
+var list []int
+
+// Make sure that conditional open-coded defers are activated correctly and run in
+// the correct order.
+func TestConditionalDefers(t *testing.T) {
+	list = make([]int, 0, 10)
+
+	defer func() {
+		if recover() != "testConditional" {
+			t.Fatal("expected panic")
+		}
+		want := []int{4, 2, 1}
+		if !reflect.DeepEqual(want, list) {
+			t.Fatal(fmt.Sprintf("wanted %v, got %v", want, list))
+		}
+
+	}()
+	testConditionalDefers(8)
+}
+
+func testConditionalDefers(n int) {
+	doappend := func(i int) {
+		list = append(list, i)
+	}
+
+	defer doappend(1)
+	if n > 5 {
+		defer doappend(2)
+		if n > 8 {
+			defer doappend(3)
+		} else {
+			defer doappend(4)
+		}
+	}
+	panic("testConditional")
+}
+
+// Test that there is no compile-time or run-time error if an open-coded defer
+// call is removed by constant propagation and dead-code elimination.
+func TestDisappearingDefer(t *testing.T) {
+	switch runtime.GOOS {
+	case "invalidOS":
+		defer func() {
+			t.Fatal("Defer shouldn't run")
+		}()
+	}
+}
+
+// This tests an extra recursive panic behavior that is only specified in the
+// code. Suppose a first panic P1 happens and starts processing defer calls. If a
+// second panic P2 happens while processing defer call D in frame F, then defer
+// call processing is restarted (with some potentially new defer calls created by
+// D or its callees). If the defer processing reaches the started defer call D
+// again in the defer stack, then the original panic P1 is aborted and cannot
+// continue panic processing or be recovered. If the panic P2 does a recover at
+// some point, it will naturally remove the original panic P1 from the stack
+// (since the original panic had to be in frame F or a descendant of F).
+func TestAbortedPanic(t *testing.T) {
+	defer func() {
+		r := recover()
+		if r != nil {
+			t.Fatal(fmt.Sprintf("wanted nil recover, got %v", r))
+		}
+	}()
+	defer func() {
+		r := recover()
+		if r != "panic2" {
+			t.Fatal(fmt.Sprintf("wanted %v, got %v", "panic2", r))
+		}
+	}()
+	defer func() {
+		panic("panic2")
+	}()
+	panic("panic1")
+}
+
+// This tests that recover() does not succeed unless it is called directly from a
+// defer function that is directly called by the panic.  Here, we first call it
+// from a defer function that is created by the defer function called directly by
+// the panic.  In
+func TestRecoverMatching(t *testing.T) {
+	defer func() {
+		r := recover()
+		if r != "panic1" {
+			t.Fatal(fmt.Sprintf("wanted %v, got %v", "panic1", r))
+		}
+	}()
+	defer func() {
+		defer func() {
+			// Shouldn't succeed, even though it is called directly
+			// from a defer function, since this defer function was
+			// not directly called by the panic.
+			r := recover()
+			if r != nil {
+				t.Fatal(fmt.Sprintf("wanted nil recover, got %v", r))
+			}
+		}()
+	}()
+	panic("panic1")
+}
+
+type nonSSAable [128]byte
+
+type bigStruct struct {
+	x, y, z, w, p, q int64
+}
+
+type containsBigStruct struct {
+	element bigStruct
+}
+
+func mknonSSAable() nonSSAable {
+	globint1++
+	return nonSSAable{0, 0, 0, 0, 5}
+}
+
+var globint1, globint2, globint3 int
+
+//go:noinline
+func sideeffect(n int64) int64 {
+	globint2++
+	return n
+}
+
+func sideeffect2(in containsBigStruct) containsBigStruct {
+	globint3++
+	return in
+}
+
+// Test that nonSSAable arguments to defer are handled correctly and only evaluated once.
+func TestNonSSAableArgs(t *testing.T) {
+	globint1 = 0
+	globint2 = 0
+	globint3 = 0
+	var save1 byte
+	var save2 int64
+	var save3 int64
+	var save4 int64
+
+	defer func() {
+		if globint1 != 1 {
+			t.Fatal(fmt.Sprintf("globint1:  wanted: 1, got %v", globint1))
+		}
+		if save1 != 5 {
+			t.Fatal(fmt.Sprintf("save1:  wanted: 5, got %v", save1))
+		}
+		if globint2 != 1 {
+			t.Fatal(fmt.Sprintf("globint2:  wanted: 1, got %v", globint2))
+		}
+		if save2 != 2 {
+			t.Fatal(fmt.Sprintf("save2:  wanted: 2, got %v", save2))
+		}
+		if save3 != 4 {
+			t.Fatal(fmt.Sprintf("save3:  wanted: 4, got %v", save3))
+		}
+		if globint3 != 1 {
+			t.Fatal(fmt.Sprintf("globint3:  wanted: 1, got %v", globint3))
+		}
+		if save4 != 4 {
+			t.Fatal(fmt.Sprintf("save1:  wanted: 4, got %v", save4))
+		}
+	}()
+
+	// Test function returning a non-SSAable arg
+	defer func(n nonSSAable) {
+		save1 = n[4]
+	}(mknonSSAable())
+	// Test composite literal that is not SSAable
+	defer func(b bigStruct) {
+		save2 = b.y
+	}(bigStruct{1, 2, 3, 4, 5, sideeffect(6)})
+
+	// Test struct field reference that is non-SSAable
+	foo := containsBigStruct{}
+	foo.element.z = 4
+	defer func(element bigStruct) {
+		save3 = element.z
+	}(foo.element)
+	defer func(element bigStruct) {
+		save4 = element.z
+	}(sideeffect2(foo).element)
+}
+
+//go:noinline
+func doPanic() {
+	panic("Test panic")
+}
+
+func TestDeferForFuncWithNoExit(t *testing.T) {
+	cond := 1
+	defer func() {
+		if cond != 2 {
+			t.Fatal(fmt.Sprintf("cond: wanted 2, got %v", cond))
+		}
+		if recover() != "Test panic" {
+			t.Fatal("Didn't find expected panic")
+		}
+	}()
+	x := 0
+	// Force a stack copy, to make sure that the &cond pointer passed to defer
+	// function is properly updated.
+	growStackIter(&x, 1000)
+	cond = 2
+	doPanic()
+
+	// This function has no exit/return, since it ends with an infinite loop
+	for {
+	}
+}
+
+// Test case approximating issue #37664, where a recursive function (interpreter)
+// may do repeated recovers/re-panics until it reaches the frame where the panic
+// can actually be handled. The recurseFnPanicRec() function is testing that there
+// are no stale defer structs on the defer chain after the interpreter() sequence,
+// by writing a bunch of 0xffffffffs into several recursive stack frames, and then
+// doing a single panic-recover which would invoke any such stale defer structs.
+func TestDeferWithRepeatedRepanics(t *testing.T) {
+	interpreter(0, 6, 2)
+	recurseFnPanicRec(0, 10)
+	interpreter(0, 5, 1)
+	recurseFnPanicRec(0, 10)
+	interpreter(0, 6, 3)
+	recurseFnPanicRec(0, 10)
+}
+
+func interpreter(level int, maxlevel int, rec int) {
+	defer func() {
+		e := recover()
+		if e == nil {
+			return
+		}
+		if level != e.(int) {
+			//fmt.Fprintln(os.Stderr, "re-panicing, level", level)
+			panic(e)
+		}
+		//fmt.Fprintln(os.Stderr, "Recovered, level", level)
+	}()
+	if level+1 < maxlevel {
+		interpreter(level+1, maxlevel, rec)
+	} else {
+		//fmt.Fprintln(os.Stderr, "Initiating panic")
+		panic(rec)
+	}
+}
+
+func recurseFnPanicRec(level int, maxlevel int) {
+	defer func() {
+		recover()
+	}()
+	recurseFn(level, maxlevel)
+}
+
+var saveInt uint32
+
+func recurseFn(level int, maxlevel int) {
+	a := [40]uint32{0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff}
+	if level+1 < maxlevel {
+		// Make sure a array is referenced, so it is not optimized away
+		saveInt = a[4]
+		recurseFn(level+1, maxlevel)
+	} else {
+		panic("recurseFn panic")
+	}
+}
+
+// Try to reproduce issue #37688, where a pointer to an open-coded defer struct is
+// mistakenly held, and that struct keeps a pointer to a stack-allocated defer
+// struct, and that stack-allocated struct gets overwritten or the stack gets
+// moved, so a memory error happens on GC.
+func TestIssue37688(t *testing.T) {
+	for j := 0; j < 10; j++ {
+		g2()
+		g3()
+	}
+}
+
+type foo struct {
+}
+
+//go:noinline
+func (f *foo) method1() {
+}
+
+//go:noinline
+func (f *foo) method2() {
+}
+
+func g2() {
+	var a foo
+	ap := &a
+	// The loop forces this defer to be heap-allocated and the remaining two
+	// to be stack-allocated.
+	for i := 0; i < 1; i++ {
+		defer ap.method1()
+	}
+	defer ap.method2()
+	defer ap.method1()
+	ff1(ap, 1, 2, 3, 4, 5, 6, 7, 8, 9)
+	// Try to get the stack to be be moved by growing it too large, so
+	// existing stack-allocated defer becomes invalid.
+	rec1(2000)
+}
+
+func g3() {
+	// Mix up the stack layout by adding in an extra function frame
+	g2()
+}
+
+var globstruct struct {
+	a, b, c, d, e, f, g, h, i int
+}
+
+func ff1(ap *foo, a, b, c, d, e, f, g, h, i int) {
+	defer ap.method1()
+
+	// Make a defer that has a very large set of args, hence big size for the
+	// defer record for the open-coded frame (which means it won't use the
+	// defer pool)
+	defer func(ap *foo, a, b, c, d, e, f, g, h, i int) {
+		if v := recover(); v != nil {
+		}
+		globstruct.a = a
+		globstruct.b = b
+		globstruct.c = c
+		globstruct.d = d
+		globstruct.e = e
+		globstruct.f = f
+		globstruct.g = g
+		globstruct.h = h
+	}(ap, a, b, c, d, e, f, g, h, i)
+	panic("ff1 panic")
+}
+
+func rec1(max int) {
+	if max > 0 {
+		rec1(max - 1)
+	}
+}
+
+func TestIssue43921(t *testing.T) {
+	defer func() {
+		expect(t, 1, recover())
+	}()
+	func() {
+		// Prevent open-coded defers
+		for {
+			defer func() {}()
+			break
+		}
+
+		defer func() {
+			defer func() {
+				expect(t, 4, recover())
+			}()
+			panic(4)
+		}()
+		panic(1)
+
+	}()
+}
+
+func expect(t *testing.T, n int, err interface{}) {
+	if n != err {
+		t.Fatalf("have %v, want %v", err, n)
+	}
+}