runtime: add GoID to StackRecord produced by GoroutineProfile()

src/internal/profilerecord/profilerecord.go

@@ -10,6 +10,7 @@ package profilerecord
 
 type StackRecord struct {
 	Stack []uintptr
+	GoID  uint64
 }
 
 type MemProfileRecord struct {

src/runtime/mprof.go

@@ -1009,6 +1009,7 @@ func mutexevent(cycles int64, skip int) {
 // A StackRecord describes a single execution stack.
 type StackRecord struct {
 	Stack0 [32]uintptr // stack trace for this record; ends at first 0 entry
+	goid   uint64      // Goroutine ID for the first record (or 0 if undefined by the struct creator).
 }
 
 // Stack returns the stack trace associated with the record,
@@ -1022,6 +1023,11 @@ func (r *StackRecord) Stack() []uintptr {
 	return r.Stack0[0:]
 }
 
+// GoID returns an identifier for the Goroutine this stack was captured for, or zero if undefined.
+func (r *StackRecord) GoID() uint64 {
+	return r.goid
+}
+
 // MemProfileRate controls the fraction of memory allocations
 // that are recorded and reported in the memory profile.
 // The profiler aims to sample an average of
@@ -1707,6 +1713,7 @@ func GoroutineProfile(p []StackRecord) (n int, ok bool) {
 	}
 	for i, mr := range records[0:n] {
 		copy(p[i].Stack0[:], mr.Stack)
+		p[i].goid = mr.GoID
 	}
 	return
 }
@@ -1735,6 +1742,7 @@ func saveg(pc, sp uintptr, gp *g, r *profilerecord.StackRecord, pcbuf []uintptr)
 	n := tracebackPCs(&u, 0, pcbuf)
 	r.Stack = make([]uintptr, n)
 	copy(r.Stack, pcbuf)
+	r.GoID = gp.goid
 }
 
 // Stack formats a stack trace of the calling goroutine into buf

src/runtime/runtime_test.go

@@ -344,17 +344,19 @@ func TestAppendSliceGrowth(t *testing.T) {
 	}
 }
 
-func TestGoroutineProfileTrivial(t *testing.T) {
+func TestGoroutineProfile(t *testing.T) {
 	// Calling GoroutineProfile twice in a row should find the same number of goroutines,
 	// but it's possible there are goroutines just about to exit, so we might end up
 	// with fewer in the second call. Try a few times; it should converge once those
 	// zombies are gone.
+	var records []StackRecord
 	for i := 0; ; i++ {
 		n1, ok := GoroutineProfile(nil) // should fail, there's at least 1 goroutine
 		if n1 < 1 || ok {
 			t.Fatalf("GoroutineProfile(nil) = %d, %v, want >0, false", n1, ok)
 		}
-		n2, ok := GoroutineProfile(make([]StackRecord, n1))
+		records = make([]StackRecord, n1)
+		n2, ok := GoroutineProfile(records)
 		if n2 == n1 && ok {
 			break
 		}
@@ -363,6 +365,17 @@ func TestGoroutineProfileTrivial(t *testing.T) {
 			t.Fatalf("GoroutineProfile not converging")
 		}
 	}
+	if len(records) < 1 {
+		t.Fatalf("GoroutineProfile hasn't collected any records")
+	}
+	for _, record := range records {
+		if len(record.Stack()) < 1 {
+			t.Fatalf("GoroutineProfile record is missing a stack trace")
+		}
+		if record.GoID() < 1 {
+			t.Fatalf("GoroutineProfile record is missing a GoID")
+		}
+	}
 }
 
 func BenchmarkGoroutineProfile(b *testing.B) {