1 files changed, 49 insertions, 6 deletions
diff --git a/src/pkg/runtime/gc_test.go b/src/pkg/runtime/gc_test.go
index 65894a6fd..e1e1b1d01 100644
--- a/src/pkg/runtime/gc_test.go
+++ b/src/pkg/runtime/gc_test.go
@@ -5,37 +5,80 @@
 package runtime_test
 
 import (
+	"os"
 	"runtime"
 	"testing"
 )
 
 func TestGcSys(t *testing.T) {
+	if os.Getenv("GOGC") == "off" {
+		t.Fatalf("GOGC=off in environment; test cannot pass")
+	}
+	data := struct{ Short bool }{testing.Short()}
+	got := executeTest(t, testGCSysSource, &data)
+	want := "OK\n"
+	if got != want {
+		t.Fatalf("expected %q, but got %q", want, got)
+	}
+}
+
+const testGCSysSource = `
+package main
+
+import (
+	"fmt"
+	"runtime"
+)
+
+func main() {
+	runtime.GOMAXPROCS(1)
 	memstats := new(runtime.MemStats)
 	runtime.GC()
 	runtime.ReadMemStats(memstats)
 	sys := memstats.Sys
 
+	runtime.MemProfileRate = 0 // disable profiler
+
 	itercount := 1000000
-	if testing.Short() {
-		itercount = 100000
-	}
+{{if .Short}}
+	itercount = 100000
+{{end}}
 	for i := 0; i < itercount; i++ {
 		workthegc()
 	}
 
 	// Should only be using a few MB.
+	// We allocated 100 MB or (if not short) 1 GB.
 	runtime.ReadMemStats(memstats)
 	if sys > memstats.Sys {
 		sys = 0
 	} else {
 		sys = memstats.Sys - sys
 	}
-	t.Logf("used %d extra bytes", sys)
-	if sys > 4<<20 {
-		t.Fatalf("using too much memory: %d bytes", sys)
+	if sys > 16<<20 {
+		fmt.Printf("using too much memory: %d bytes\n", sys)
+		return
 	}
+	fmt.Printf("OK\n")
 }
 
 func workthegc() []byte {
 	return make([]byte, 1029)
 }
+`
+
+func TestGcDeepNesting(t *testing.T) {
+	type T [2][2][2][2][2][2][2][2][2][2]*int
+	a := new(T)
+
+	// Prevent the compiler from applying escape analysis.
+	// This makes sure new(T) is allocated on heap, not on the stack.
+	t.Logf("%p", a)
+
+	a[0][0][0][0][0][0][0][0][0][0] = new(int)
+	*a[0][0][0][0][0][0][0][0][0][0] = 13
+	runtime.GC()
+	if *a[0][0][0][0][0][0][0][0][0][0] != 13 {
+		t.Fail()
+	}
+}