runtime: handle windows exceptions, even in cgo programs

Fixes #3543.

R=golang-dev, kardianos, rsc
CC=golang-dev, hectorchu, vcc.163
https://golang.org/cl/6245063

src/pkg/runtime/crash_test.go

@@ -0,0 +1,100 @@
+// Copyright 2012 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 (
+	"io/ioutil"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"testing"
+	"text/template"
+)
+
+type crashTest struct {
+	Cgo bool
+}
+
+// This test is a separate program, because it is testing
+// both main (m0) and non-main threads (m).
+
+func testCrashHandler(t *testing.T, ct *crashTest) {
+	st := template.Must(template.New("crashSource").Parse(crashSource))
+
+	dir, err := ioutil.TempDir("", "go-build")
+	if err != nil {
+		t.Fatalf("failed to create temp directory: %v", err)
+	}
+	defer os.RemoveAll(dir)
+
+	src := filepath.Join(dir, "main.go")
+	f, err := os.Create(src)
+	if err != nil {
+		t.Fatalf("failed to create %v: %v", src, err)
+	}
+	err = st.Execute(f, ct)
+	if err != nil {
+		f.Close()
+		t.Fatalf("failed to execute template: %v", err)
+	}
+	f.Close()
+
+	got, err := exec.Command("go", "run", src).CombinedOutput()
+	if err != nil {
+		t.Fatalf("program exited with error: %v\n%v", err, string(got))
+	}
+	want := "main: recovered done\nnew-thread: recovered done\nsecond-new-thread: recovered done\nmain-again: recovered done\n"
+	if string(got) != string(want) {
+		t.Fatalf("expected %q, but got %q", string(want), string(got))
+	}
+}
+
+func TestCrashHandler(t *testing.T) {
+	testCrashHandler(t, &crashTest{Cgo: false})
+}
+
+const crashSource = `
+package main
+
+import (
+	"fmt"
+	"runtime"
+)
+
+{{if .Cgo}}
+import "C"
+{{end}}
+
+func test(name string) {
+	defer func() {
+		if x := recover(); x != nil {
+			fmt.Printf(" recovered")
+		}
+		fmt.Printf(" done\n")
+	}()
+	fmt.Printf("%s:", name)
+	var s *string
+	_ = *s
+	fmt.Print("SHOULD NOT BE HERE")
+}
+
+func testInNewThread(name string) {
+	c := make(chan bool)
+	go func() {
+		runtime.LockOSThread()
+		test(name)
+		c <- true
+	}()
+	<-c
+}
+
+func main() {
+	runtime.LockOSThread()
+	test("main")
+	testInNewThread("new-thread")
+	testInNewThread("second-new-thread")
+	test("main-again")
+}
+`