/
pcln.go
565 lines (481 loc) · 14.7 KB
/
pcln.go
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
// Copyright 2013 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package ld
import (
"cmd/internal/objabi"
"cmd/internal/src"
"cmd/internal/sys"
"cmd/link/internal/sym"
"log"
"os"
"path/filepath"
"strings"
)
// iteration over encoded pcdata tables.
func getvarint(pp *[]byte) uint32 {
v := uint32(0)
p := *pp
for shift := 0; ; shift += 7 {
v |= uint32(p[0]&0x7F) << uint(shift)
tmp4 := p
p = p[1:]
if tmp4[0]&0x80 == 0 {
break
}
}
*pp = p
return v
}
func pciternext(it *Pciter) {
it.pc = it.nextpc
if it.done != 0 {
return
}
if -cap(it.p) >= -cap(it.d.P[len(it.d.P):]) {
it.done = 1
return
}
// value delta
v := getvarint(&it.p)
if v == 0 && it.start == 0 {
it.done = 1
return
}
it.start = 0
dv := int32(v>>1) ^ (int32(v<<31) >> 31)
it.value += dv
// pc delta
v = getvarint(&it.p)
it.nextpc = it.pc + v*it.pcscale
}
func pciterinit(ctxt *Link, it *Pciter, d *sym.Pcdata) {
it.d = *d
it.p = it.d.P
it.pc = 0
it.nextpc = 0
it.value = -1
it.start = 1
it.done = 0
it.pcscale = uint32(ctxt.Arch.MinLC)
pciternext(it)
}
func addvarint(d *sym.Pcdata, val uint32) {
n := int32(0)
for v := val; v >= 0x80; v >>= 7 {
n++
}
n++
old := len(d.P)
for cap(d.P) < len(d.P)+int(n) {
d.P = append(d.P[:cap(d.P)], 0)
}
d.P = d.P[:old+int(n)]
p := d.P[old:]
var v uint32
for v = val; v >= 0x80; v >>= 7 {
p[0] = byte(v | 0x80)
p = p[1:]
}
p[0] = byte(v)
}
func addpctab(ctxt *Link, ftab *sym.Symbol, off int32, d *sym.Pcdata) int32 {
var start int32
if len(d.P) > 0 {
start = int32(len(ftab.P))
ftab.AddBytes(d.P)
}
return int32(ftab.SetUint32(ctxt.Arch, int64(off), uint32(start)))
}
func ftabaddstring(ctxt *Link, ftab *sym.Symbol, s string) int32 {
n := int32(len(s)) + 1
start := int32(len(ftab.P))
ftab.Grow(int64(start) + int64(n) + 1)
copy(ftab.P[start:], s)
return start
}
// numberfile assigns a file number to the file if it hasn't been assigned already.
func numberfile(ctxt *Link, file *sym.Symbol) {
if file.Type != sym.SFILEPATH {
ctxt.Filesyms = append(ctxt.Filesyms, file)
file.Value = int64(len(ctxt.Filesyms))
file.Type = sym.SFILEPATH
path := file.Name[len(src.FileSymPrefix):]
file.Name = expandGoroot(path)
}
}
func renumberfiles(ctxt *Link, files []*sym.Symbol, d *sym.Pcdata) {
// Give files numbers.
for _, f := range files {
numberfile(ctxt, f)
}
newval := int32(-1)
var out sym.Pcdata
var it Pciter
for pciterinit(ctxt, &it, d); it.done == 0; pciternext(&it) {
// value delta
oldval := it.value
var val int32
if oldval == -1 {
val = -1
} else {
if oldval < 0 || oldval >= int32(len(files)) {
log.Fatalf("bad pcdata %d", oldval)
}
val = int32(files[oldval].Value)
}
dv := val - newval
newval = val
v := (uint32(dv) << 1) ^ uint32(dv>>31)
addvarint(&out, v)
// pc delta
addvarint(&out, (it.nextpc-it.pc)/it.pcscale)
}
// terminating value delta
addvarint(&out, 0)
*d = out
}
// onlycsymbol reports whether this is a symbol that is referenced by C code.
func onlycsymbol(s *sym.Symbol) bool {
switch s.Name {
case "_cgo_topofstack", "_cgo_panic", "crosscall2":
return true
}
if strings.HasPrefix(s.Name, "_cgoexp_") {
return true
}
return false
}
func emitPcln(ctxt *Link, s *sym.Symbol) bool {
if s == nil {
return true
}
if ctxt.BuildMode == BuildModePlugin && ctxt.HeadType == objabi.Hdarwin && onlycsymbol(s) {
return false
}
// We want to generate func table entries only for the "lowest level" symbols,
// not containers of subsymbols.
if s.Attr.Container() {
return true
}
return true
}
// pclntab initializes the pclntab symbol with
// runtime function and file name information.
var pclntabZpcln sym.FuncInfo
// These variables are used to initialize runtime.firstmoduledata, see symtab.go:symtab.
var pclntabNfunc int32
var pclntabFiletabOffset int32
var pclntabPclntabOffset int32
var pclntabFirstFunc *sym.Symbol
var pclntabLastFunc *sym.Symbol
func (ctxt *Link) pclntab() {
funcdataBytes := int64(0)
ftab := ctxt.Syms.Lookup("runtime.pclntab", 0)
ftab.Type = sym.SPCLNTAB
ftab.Attr |= sym.AttrReachable
// See golang.org/s/go12symtab for the format. Briefly:
// 8-byte header
// nfunc [thearch.ptrsize bytes]
// function table, alternating PC and offset to func struct [each entry thearch.ptrsize bytes]
// end PC [thearch.ptrsize bytes]
// offset to file table [4 bytes]
nfunc := int32(0)
// Find container symbols and mark them as such.
for _, s := range ctxt.Textp {
if s.Outer != nil {
s.Outer.Attr |= sym.AttrContainer
}
}
for _, s := range ctxt.Textp {
if emitPcln(ctxt, s) {
nfunc++
}
}
pclntabNfunc = nfunc
ftab.Grow(8 + int64(ctxt.Arch.PtrSize) + int64(nfunc)*2*int64(ctxt.Arch.PtrSize) + int64(ctxt.Arch.PtrSize) + 4)
ftab.SetUint32(ctxt.Arch, 0, 0xfffffffb)
ftab.SetUint8(ctxt.Arch, 6, uint8(ctxt.Arch.MinLC))
ftab.SetUint8(ctxt.Arch, 7, uint8(ctxt.Arch.PtrSize))
ftab.SetUint(ctxt.Arch, 8, uint64(nfunc))
pclntabPclntabOffset = int32(8 + ctxt.Arch.PtrSize)
funcnameoff := make(map[string]int32)
nameToOffset := func(name string) int32 {
nameoff, ok := funcnameoff[name]
if !ok {
nameoff = ftabaddstring(ctxt, ftab, name)
funcnameoff[name] = nameoff
}
return nameoff
}
nfunc = 0
var last *sym.Symbol
for _, s := range ctxt.Textp {
last = s
if !emitPcln(ctxt, s) {
continue
}
pcln := s.FuncInfo
if pcln == nil {
pcln = &pclntabZpcln
}
if pclntabFirstFunc == nil {
pclntabFirstFunc = s
}
if len(pcln.InlTree) > 0 {
if len(pcln.Pcdata) <= objabi.PCDATA_InlTreeIndex {
// Create inlining pcdata table.
pcdata := make([]sym.Pcdata, objabi.PCDATA_InlTreeIndex+1)
copy(pcdata, pcln.Pcdata)
pcln.Pcdata = pcdata
}
if len(pcln.Funcdataoff) <= objabi.FUNCDATA_InlTree {
// Create inline tree funcdata.
funcdata := make([]*sym.Symbol, objabi.FUNCDATA_InlTree+1)
funcdataoff := make([]int64, objabi.FUNCDATA_InlTree+1)
copy(funcdata, pcln.Funcdata)
copy(funcdataoff, pcln.Funcdataoff)
pcln.Funcdata = funcdata
pcln.Funcdataoff = funcdataoff
}
}
funcstart := int32(len(ftab.P))
funcstart += int32(-len(ftab.P)) & (int32(ctxt.Arch.PtrSize) - 1)
ftab.SetAddr(ctxt.Arch, 8+int64(ctxt.Arch.PtrSize)+int64(nfunc)*2*int64(ctxt.Arch.PtrSize), s)
ftab.SetUint(ctxt.Arch, 8+int64(ctxt.Arch.PtrSize)+int64(nfunc)*2*int64(ctxt.Arch.PtrSize)+int64(ctxt.Arch.PtrSize), uint64(funcstart))
// Write runtime._func. Keep in sync with ../../../../runtime/runtime2.go:/_func
// and package debug/gosym.
// fixed size of struct, checked below
off := funcstart
end := funcstart + int32(ctxt.Arch.PtrSize) + 3*4 + 5*4 + int32(len(pcln.Pcdata))*4 + int32(len(pcln.Funcdata))*int32(ctxt.Arch.PtrSize)
if len(pcln.Funcdata) > 0 && (end&int32(ctxt.Arch.PtrSize-1) != 0) {
end += 4
}
ftab.Grow(int64(end))
// entry uintptr
off = int32(ftab.SetAddr(ctxt.Arch, int64(off), s))
// name int32
nameoff := nameToOffset(s.Name)
off = int32(ftab.SetUint32(ctxt.Arch, int64(off), uint32(nameoff)))
// args int32
// TODO: Move into funcinfo.
args := uint32(0)
if s.FuncInfo != nil {
args = uint32(s.FuncInfo.Args)
}
off = int32(ftab.SetUint32(ctxt.Arch, int64(off), args))
// deferreturn
deferreturn := uint32(0)
lastWasmAddr := uint32(0)
for _, r := range s.R {
if ctxt.Arch.Family == sys.Wasm && r.Type == objabi.R_ADDR {
// Wasm does not have a live variable set at the deferreturn
// call itself. Instead it has one identified by the
// resumption point immediately preceding the deferreturn.
// The wasm code has a R_ADDR relocation which is used to
// set the resumption point to PC_B.
lastWasmAddr = uint32(r.Add)
}
if r.Type.IsDirectJump() && r.Sym != nil && r.Sym.Name == "runtime.deferreturn" {
if ctxt.Arch.Family == sys.Wasm {
deferreturn = lastWasmAddr
} else {
// Note: the relocation target is in the call instruction, but
// is not necessarily the whole instruction (for instance, on
// x86 the relocation applies to bytes [1:5] of the 5 byte call
// instruction).
deferreturn = uint32(r.Off)
}
break // only need one
}
}
off = int32(ftab.SetUint32(ctxt.Arch, int64(off), deferreturn))
if pcln != &pclntabZpcln {
renumberfiles(ctxt, pcln.File, &pcln.Pcfile)
if false {
// Sanity check the new numbering
var it Pciter
for pciterinit(ctxt, &it, &pcln.Pcfile); it.done == 0; pciternext(&it) {
if it.value < 1 || it.value > int32(len(ctxt.Filesyms)) {
Errorf(s, "bad file number in pcfile: %d not in range [1, %d]\n", it.value, len(ctxt.Filesyms))
errorexit()
}
}
}
}
if len(pcln.InlTree) > 0 {
inlTreeSym := ctxt.Syms.Lookup("inltree."+s.Name, 0)
inlTreeSym.Type = sym.SRODATA
inlTreeSym.Attr |= sym.AttrReachable | sym.AttrDuplicateOK
for i, call := range pcln.InlTree {
// Usually, call.File is already numbered since the file
// shows up in the Pcfile table. However, two inlined calls
// might overlap exactly so that only the innermost file
// appears in the Pcfile table. In that case, this assigns
// the outer file a number.
numberfile(ctxt, call.File)
nameoff := nameToOffset(call.Func.Name)
inlTreeSym.SetUint16(ctxt.Arch, int64(i*20+0), uint16(call.Parent))
inlTreeSym.SetUint8(ctxt.Arch, int64(i*20+2), uint8(objabi.GetFuncID(call.Func.Name, call.Func.File)))
// byte 3 is unused
inlTreeSym.SetUint32(ctxt.Arch, int64(i*20+4), uint32(call.File.Value))
inlTreeSym.SetUint32(ctxt.Arch, int64(i*20+8), uint32(call.Line))
inlTreeSym.SetUint32(ctxt.Arch, int64(i*20+12), uint32(nameoff))
inlTreeSym.SetUint32(ctxt.Arch, int64(i*20+16), uint32(call.ParentPC))
}
pcln.Funcdata[objabi.FUNCDATA_InlTree] = inlTreeSym
pcln.Pcdata[objabi.PCDATA_InlTreeIndex] = pcln.Pcinline
}
// pcdata
off = addpctab(ctxt, ftab, off, &pcln.Pcsp)
off = addpctab(ctxt, ftab, off, &pcln.Pcfile)
off = addpctab(ctxt, ftab, off, &pcln.Pcline)
off = int32(ftab.SetUint32(ctxt.Arch, int64(off), uint32(len(pcln.Pcdata))))
// funcID uint8
var file string
if s.FuncInfo != nil && len(s.FuncInfo.File) > 0 {
file = s.FuncInfo.File[0].Name
}
funcID := objabi.GetFuncID(s.Name, file)
off = int32(ftab.SetUint8(ctxt.Arch, int64(off), uint8(funcID)))
// unused
off += 2
// nfuncdata must be the final entry.
off = int32(ftab.SetUint8(ctxt.Arch, int64(off), uint8(len(pcln.Funcdata))))
for i := range pcln.Pcdata {
off = addpctab(ctxt, ftab, off, &pcln.Pcdata[i])
}
// funcdata, must be pointer-aligned and we're only int32-aligned.
// Missing funcdata will be 0 (nil pointer).
if len(pcln.Funcdata) > 0 {
if off&int32(ctxt.Arch.PtrSize-1) != 0 {
off += 4
}
for i := range pcln.Funcdata {
if pcln.Funcdata[i] == nil {
ftab.SetUint(ctxt.Arch, int64(off)+int64(ctxt.Arch.PtrSize)*int64(i), uint64(pcln.Funcdataoff[i]))
} else {
// TODO: Dedup.
funcdataBytes += pcln.Funcdata[i].Size
ftab.SetAddrPlus(ctxt.Arch, int64(off)+int64(ctxt.Arch.PtrSize)*int64(i), pcln.Funcdata[i], pcln.Funcdataoff[i])
}
}
off += int32(len(pcln.Funcdata)) * int32(ctxt.Arch.PtrSize)
}
if off != end {
Errorf(s, "bad math in functab: funcstart=%d off=%d but end=%d (npcdata=%d nfuncdata=%d ptrsize=%d)", funcstart, off, end, len(pcln.Pcdata), len(pcln.Funcdata), ctxt.Arch.PtrSize)
errorexit()
}
nfunc++
}
pclntabLastFunc = last
// Final entry of table is just end pc.
ftab.SetAddrPlus(ctxt.Arch, 8+int64(ctxt.Arch.PtrSize)+int64(nfunc)*2*int64(ctxt.Arch.PtrSize), last, last.Size)
// Start file table.
start := int32(len(ftab.P))
start += int32(-len(ftab.P)) & (int32(ctxt.Arch.PtrSize) - 1)
pclntabFiletabOffset = start
ftab.SetUint32(ctxt.Arch, 8+int64(ctxt.Arch.PtrSize)+int64(nfunc)*2*int64(ctxt.Arch.PtrSize)+int64(ctxt.Arch.PtrSize), uint32(start))
ftab.Grow(int64(start) + (int64(len(ctxt.Filesyms))+1)*4)
ftab.SetUint32(ctxt.Arch, int64(start), uint32(len(ctxt.Filesyms)+1))
for i := len(ctxt.Filesyms) - 1; i >= 0; i-- {
s := ctxt.Filesyms[i]
ftab.SetUint32(ctxt.Arch, int64(start)+s.Value*4, uint32(ftabaddstring(ctxt, ftab, s.Name)))
}
ftab.Size = int64(len(ftab.P))
if ctxt.Debugvlog != 0 {
ctxt.Logf("%5.2f pclntab=%d bytes, funcdata total %d bytes\n", Cputime(), ftab.Size, funcdataBytes)
}
}
func gorootFinal() string {
root := objabi.GOROOT
if final := os.Getenv("GOROOT_FINAL"); final != "" {
root = final
}
return root
}
func expandGoroot(s string) string {
const n = len("$GOROOT")
if len(s) >= n+1 && s[:n] == "$GOROOT" && (s[n] == '/' || s[n] == '\\') {
return filepath.ToSlash(filepath.Join(gorootFinal(), s[n:]))
}
return s
}
const (
BUCKETSIZE = 256 * MINFUNC
SUBBUCKETS = 16
SUBBUCKETSIZE = BUCKETSIZE / SUBBUCKETS
NOIDX = 0x7fffffff
)
// findfunctab generates a lookup table to quickly find the containing
// function for a pc. See src/runtime/symtab.go:findfunc for details.
func (ctxt *Link) findfunctab() {
t := ctxt.Syms.Lookup("runtime.findfunctab", 0)
t.Type = sym.SRODATA
t.Attr |= sym.AttrReachable
t.Attr |= sym.AttrLocal
// find min and max address
min := ctxt.Textp[0].Value
lastp := ctxt.Textp[len(ctxt.Textp)-1]
max := lastp.Value + lastp.Size
// for each subbucket, compute the minimum of all symbol indexes
// that map to that subbucket.
n := int32((max - min + SUBBUCKETSIZE - 1) / SUBBUCKETSIZE)
indexes := make([]int32, n)
for i := int32(0); i < n; i++ {
indexes[i] = NOIDX
}
idx := int32(0)
for i, s := range ctxt.Textp {
if !emitPcln(ctxt, s) {
continue
}
p := s.Value
var e *sym.Symbol
i++
if i < len(ctxt.Textp) {
e = ctxt.Textp[i]
}
for !emitPcln(ctxt, e) && i < len(ctxt.Textp) {
e = ctxt.Textp[i]
i++
}
q := max
if e != nil {
q = e.Value
}
//print("%d: [%lld %lld] %s\n", idx, p, q, s->name);
for ; p < q; p += SUBBUCKETSIZE {
i = int((p - min) / SUBBUCKETSIZE)
if indexes[i] > idx {
indexes[i] = idx
}
}
i = int((q - 1 - min) / SUBBUCKETSIZE)
if indexes[i] > idx {
indexes[i] = idx
}
idx++
}
// allocate table
nbuckets := int32((max - min + BUCKETSIZE - 1) / BUCKETSIZE)
t.Grow(4*int64(nbuckets) + int64(n))
// fill in table
for i := int32(0); i < nbuckets; i++ {
base := indexes[i*SUBBUCKETS]
if base == NOIDX {
Errorf(nil, "hole in findfunctab")
}
t.SetUint32(ctxt.Arch, int64(i)*(4+SUBBUCKETS), uint32(base))
for j := int32(0); j < SUBBUCKETS && i*SUBBUCKETS+j < n; j++ {
idx = indexes[i*SUBBUCKETS+j]
if idx == NOIDX {
Errorf(nil, "hole in findfunctab")
}
if idx-base >= 256 {
Errorf(nil, "too many functions in a findfunc bucket! %d/%d %d %d", i, nbuckets, j, idx-base)
}
t.SetUint8(ctxt.Arch, int64(i)*(4+SUBBUCKETS)+4+int64(j), uint8(idx-base))
}
}
}