runtime: add TestCgoDLLImports

The test is a simple reproduction of issue 9356.

Update #8948.
Update #9356.

Change-Id: Ia77bc36d12ed0c3c4a8b1214cade8be181c9ad55
Reviewed-on: https://go-review.googlesource.com/7618Reviewed-by: Minux Ma <minux@golang.org>

src/runtime/crash_cgo_test.go

@@ -82,6 +82,18 @@ func TestCgoExternalThreadSIGPROF(t *testing.T) {
 	}
 }
 
+func TestCgoDLLImports(t *testing.T) {
+	// test issue 9356
+	if runtime.GOOS != "windows" {
+		t.Skip("skipping windows specific test")
+	}
+	got := executeTest(t, cgoDLLImportsMainSource, nil, "a/a.go", cgoDLLImportsPkgSource)
+	want := "OK\n"
+	if got != want {
+		t.Fatalf("expected %q, but got %v", want, got)
+	}
+}
+
 const cgoSignalDeadlockSource = `
 package main
 
@@ -269,3 +281,43 @@ func main() {
 	println("OK")
 }
 `
+
+const cgoDLLImportsMainSource = `
+package main
+
+/*
+#include <windows.h>
+
+DWORD getthread() {
+	return GetCurrentThreadId();
+}
+*/
+import "C"
+
+import "./a"
+
+func main() {
+	C.getthread()
+	a.GetThread()
+	println("OK")
+}
+`
+
+const cgoDLLImportsPkgSource = `
+package a
+
+/*
+#cgo CFLAGS: -mnop-fun-dllimport
+
+#include <windows.h>
+
+DWORD agetthread() {
+	return GetCurrentThreadId();
+}
+*/
+import "C"
+
+func GetThread() uint32 {
+	return uint32(C.agetthread())
+}
+`

src/runtime/crash_test.go

@@ -72,7 +72,14 @@ func executeTest(t *testing.T, templ string, data interface{}, extra ...string)
 	}
 
 	for i := 0; i < len(extra); i += 2 {
-		if err := ioutil.WriteFile(filepath.Join(dir, extra[i]), []byte(extra[i+1]), 0666); err != nil {
+		fname := extra[i]
+		contents := extra[i+1]
+		if d, _ := filepath.Split(fname); d != "" {
+			if err := os.Mkdir(filepath.Join(dir, d), 0755); err != nil {
+				t.Fatal(err)
+			}
+		}
+		if err := ioutil.WriteFile(filepath.Join(dir, fname), []byte(contents), 0666); err != nil {
 			t.Fatal(err)
 		}
 	}