1package wazevoapi
2
3import (
4 "fmt"
5 "os"
6 "strconv"
7 "sync"
8)
9
10var PerfMap *Perfmap
11
12func init() {
13 if PerfMapEnabled {
14 pid := os.Getpid()
15 filename := "/tmp/perf-" + strconv.Itoa(pid) + ".map"
16
17 fh, err := os.OpenFile(filename, os.O_APPEND|os.O_RDWR|os.O_CREATE, 0o644)
18 if err != nil {
19 panic(err)
20 }
21
22 PerfMap = &Perfmap{fh: fh}
23 }
24}
25
26// Perfmap holds perfmap entries to be flushed into a perfmap file.
27type Perfmap struct {
28 entries []entry
29 mux sync.Mutex
30 fh *os.File
31}
32
33type entry struct {
34 index int
35 offset int64
36 size uint64
37 name string
38}
39
40func (f *Perfmap) Lock() {
41 f.mux.Lock()
42}
43
44func (f *Perfmap) Unlock() {
45 f.mux.Unlock()
46}
47
48// AddModuleEntry adds a perfmap entry into the perfmap file.
49// index is the index of the function in the module, offset is the offset of the function in the module,
50// size is the size of the function, and name is the name of the function.
51//
52// Note that the entries are not flushed into the perfmap file until Flush is called,
53// and the entries are module-scoped; Perfmap must be locked until Flush is called.
54func (f *Perfmap) AddModuleEntry(index int, offset int64, size uint64, name string) {
55 e := entry{index: index, offset: offset, size: size, name: name}
56 if f.entries == nil {
57 f.entries = []entry{e}
58 return
59 }
60 f.entries = append(f.entries, e)
61}
62
63// Flush writes the perfmap entries into the perfmap file where the entries are adjusted by the given `addr` and `functionOffsets`.
64func (f *Perfmap) Flush(addr uintptr, functionOffsets []int) {
65 defer func() {
66 _ = f.fh.Sync()
67 }()
68
69 for _, e := range f.entries {
70 if _, err := f.fh.WriteString(fmt.Sprintf("%x %s %s\n",
71 uintptr(e.offset)+addr+uintptr(functionOffsets[e.index]),
72 strconv.FormatUint(e.size, 16),
73 e.name,
74 )); err != nil {
75 panic(err)
76 }
77 }
78 f.entries = f.entries[:0]
79}
80
81// Clear clears the perfmap entries not yet flushed.
82func (f *Perfmap) Clear() {
83 f.entries = f.entries[:0]
84}
85
86// AddEntry writes a perfmap entry directly into the perfmap file, not using the entries.
87func (f *Perfmap) AddEntry(addr uintptr, size uint64, name string) {
88 _, err := f.fh.WriteString(fmt.Sprintf("%x %s %s\n",
89 addr,
90 strconv.FormatUint(size, 16),
91 name,
92 ))
93 if err != nil {
94 panic(err)
95 }
96}