1// run -gcflags -l=4
2
3// Copyright 2017 The Go Authors. All rights reserved.
4// Use of this source code is governed by a BSD-style
5// license that can be found in the LICENSE file.
6
7package main
8
9import (
10	"fmt"
11	"runtime"
12)
13
14type frame struct {
15	pc   uintptr
16	file string
17	line int
18	ok   bool
19}
20
21var (
22	skip        int
23	globalFrame frame
24)
25
26func f() {
27	g() // line 27
28}
29
30func g() {
31	h() // line 31
32}
33
34func h() {
35	x := &globalFrame
36	x.pc, x.file, x.line, x.ok = runtime.Caller(skip) // line 36
37}
38
39//go:noinline
40func testCaller(skp int) frame {
41	skip = skp
42	f() // line 42
43	frame := globalFrame
44	if !frame.ok {
45		panic(fmt.Sprintf("skip=%d runtime.Caller failed", skp))
46	}
47	return frame
48}
49
50type wantFrame struct {
51	funcName string
52	line     int
53}
54
55// -1 means don't care
56var expected = []wantFrame{
57	0: {"main.h", 36},
58	1: {"main.g", 31},
59	2: {"main.f", 27},
60	3: {"main.testCaller", 42},
61	4: {"main.main", 68},
62	5: {"runtime.main", -1},
63	6: {"runtime.goexit", -1},
64}
65
66func main() {
67	for i := 0; i <= 6; i++ {
68		frame := testCaller(i) // line 68
69		fn := runtime.FuncForPC(frame.pc)
70		if expected[i].line >= 0 && frame.line != expected[i].line {
71			panic(fmt.Sprintf("skip=%d expected line %d, got line %d", i, expected[i].line, frame.line))
72		}
73		if fn.Name() != expected[i].funcName {
74			panic(fmt.Sprintf("skip=%d expected function %s, got %s", i, expected[i].funcName, fn.Name()))
75		}
76	}
77}
78