-
Notifications
You must be signed in to change notification settings - Fork 0
/
bexport.go
1910 lines (1642 loc) · 46.9 KB
/
bexport.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
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
// Copyright 2015 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.
// Binary package export.
// (see fmt.go, parser.go as "documentation" for how to use/setup data structures)
/*
1) Export data encoding principles:
The export data is a serialized description of the graph of exported
"objects": constants, types, variables, and functions. In general,
types - but also objects referred to from inlined function bodies -
can be reexported and so we need to know which package they are coming
from. Therefore, packages are also part of the export graph.
The roots of the graph are two lists of objects. The 1st list (phase 1,
see Export) contains all objects that are exported at the package level.
These objects are the full representation of the package's API, and they
are the only information a platform-independent tool (e.g., go/types)
needs to know to type-check against a package.
The 2nd list of objects contains all objects referred to from exported
inlined function bodies. These objects are needed by the compiler to
make sense of the function bodies; the exact list contents are compiler-
specific.
Finally, the export data contains a list of representations for inlined
function bodies. The format of this representation is compiler specific.
The graph is serialized in in-order fashion, starting with the roots.
Each object in the graph is serialized by writing its fields sequentially.
If the field is a pointer to another object, that object is serialized,
recursively. Otherwise the field is written. Non-pointer fields are all
encoded as integer or string values.
Some objects (packages, types) may be referred to more than once. When
reaching an object that was not serialized before, an integer _index_
is assigned to it, starting at 0. In this case, the encoding starts
with an integer _tag_ < 0. The tag value indicates the kind of object
that follows and that this is the first time that we see this object.
If the object was already serialized, the encoding is simply the object
index >= 0. An importer can trivially determine if an object needs to
be read in for the first time (tag < 0) and entered into the respective
object table, or if the object was seen already (index >= 0), in which
case the index is used to look up the object in a table.
Before exporting or importing, the type tables are populated with the
predeclared types (int, string, error, unsafe.Pointer, etc.). This way
they are automatically encoded with a known and fixed type index.
2) Encoding format:
The export data starts with two newline-terminated strings: a version
string and either an empty string, or "debug", when emitting the debug
format. These strings are followed by version-specific encoding options.
(The Go1.7 version starts with a couple of bytes specifying the format.
That format encoding is no longer used but is supported to avoid spurious
errors when importing old installed package files.)
The header is followed by the package object for the exported package,
two lists of objects, and the list of inlined function bodies.
The encoding of objects is straight-forward: Constants, variables, and
functions start with their name, type, and possibly a value. Named types
record their name and package so that they can be canonicalized: If the
same type was imported before via another import, the importer must use
the previously imported type pointer so that we have exactly one version
(i.e., one pointer) for each named type (and read but discard the current
type encoding). Unnamed types simply encode their respective fields.
In the encoding, some lists start with the list length. Some lists are
terminated with an end marker (usually for lists where we may not know
the length a priori).
Integers use variable-length encoding for compact representation.
Strings are canonicalized similar to objects that may occur multiple times:
If the string was exported already, it is represented by its index only.
Otherwise, the export data starts with the negative string length (negative,
so we can distinguish from string index), followed by the string bytes.
The empty string is mapped to index 0. (The initial format string is an
exception; it is encoded as the string bytes followed by a newline).
The exporter and importer are completely symmetric in implementation: For
each encoding routine there is a matching and symmetric decoding routine.
This symmetry makes it very easy to change or extend the format: If a new
field needs to be encoded, a symmetric change can be made to exporter and
importer.
3) Making changes to the encoding format:
Any change to the encoding format requires a respective change in the
exporter below and a corresponding symmetric change to the importer in
bimport.go.
Furthermore, it requires a corresponding change to go/internal/gcimporter
and golang.org/x/tools/go/gcimporter15. Changes to the latter must preserve
compatibility with both the last release of the compiler, and with the
corresponding compiler at tip. That change is necessarily more involved,
as it must switch based on the version number in the export data file.
It is recommended to turn on debugFormat when working on format changes
as it will help finding encoding/decoding inconsistencies quickly.
Special care must be taken to update builtin.go when the export format
changes: builtin.go contains the export data obtained by compiling the
builtin/runtime.go and builtin/unsafe.go files; those compilations in
turn depend on importing the data in builtin.go. Thus, when the export
data format changes, the compiler must be able to import the data in
builtin.go even if its format has not yet changed. Proceed in several
steps as follows:
- Change the exporter to use the new format, and use a different version
string as well.
- Update the importer accordingly, but accept both the old and the new
format depending on the version string.
- all.bash should pass at this point.
- Run mkbuiltin.go: this will create a new builtin.go using the new
export format.
- go test -run Builtin should pass at this point.
- Remove importer support for the old export format and (maybe) revert
the version string again (it's only needed to mark the transition).
- all.bash should still pass.
Don't forget to set debugFormat to false.
*/
package gc
import (
"bufio"
"bytes"
"cmd/compile/internal/big"
"encoding/binary"
"fmt"
"sort"
"strings"
)
// If debugFormat is set, each integer and string value is preceded by a marker
// and position information in the encoding. This mechanism permits an importer
// to recognize immediately when it is out of sync. The importer recognizes this
// mode automatically (i.e., it can import export data produced with debugging
// support even if debugFormat is not set at the time of import). This mode will
// lead to massively larger export data (by a factor of 2 to 3) and should only
// be enabled during development and debugging.
//
// NOTE: This flag is the first flag to enable if importing dies because of
// (suspected) format errors, and whenever a change is made to the format.
const debugFormat = false // default: false
// forceObjFileStability enforces additional constraints in export data
// and other parts of the compiler to eliminate object file differences
// only due to the choice of export format.
// TODO(gri) disable and remove once there is only one export format again
const forceObjFileStability = true
// Current export format version. Increase with each format change.
const exportVersion = 1
// exportInlined enables the export of inlined function bodies and related
// dependencies. The compiler should work w/o any loss of functionality with
// the flag disabled, but the generated code will lose access to inlined
// function bodies across packages, leading to performance bugs.
// Leave for debugging.
const exportInlined = true // default: true
// trackAllTypes enables cycle tracking for all types, not just named
// types. The existing compiler invariants assume that unnamed types
// that are not completely set up are not used, or else there are spurious
// errors.
// If disabled, only named types are tracked, possibly leading to slightly
// less efficient encoding in rare cases. It also prevents the export of
// some corner-case type declarations (but those were not handled correctly
// with the former textual export format either).
// TODO(gri) enable and remove once issues caused by it are fixed
const trackAllTypes = false
type exporter struct {
out *bufio.Writer
// object -> index maps, indexed in order of serialization
strIndex map[string]int
pkgIndex map[*Pkg]int
typIndex map[*Type]int
funcList []*Func
// position encoding
posInfoFormat bool
prevFile string
prevLine int
// debugging support
written int // bytes written
indent int // for p.trace
trace bool
// work-around for issue #16369 only
nesting int // amount of "nesting" of interface types
}
// export writes the exportlist for localpkg to out and returns the number of bytes written.
func export(out *bufio.Writer, trace bool) int {
p := exporter{
out: out,
strIndex: map[string]int{"": 0}, // empty string is mapped to 0
pkgIndex: make(map[*Pkg]int),
typIndex: make(map[*Type]int),
// don't emit pos info for builtin packages
// (not needed and avoids path name diffs in builtin.go between
// Windows and non-Windows machines, exposed via builtin_test.go)
posInfoFormat: Debug['A'] == 0,
trace: trace,
}
// write version info
// The version string must start with "version %d" where %d is the version
// number. Additional debugging information may follow after a blank; that
// text is ignored by the importer.
p.rawStringln(fmt.Sprintf("version %d", exportVersion))
var debug string
if debugFormat {
debug = "debug"
}
p.rawStringln(debug) // cannot use p.bool since it's affected by debugFormat; also want to see this clearly
p.bool(trackAllTypes)
p.bool(p.posInfoFormat)
// --- generic export data ---
// populate type map with predeclared "known" types
predecl := predeclared()
for index, typ := range predecl {
p.typIndex[typ] = index
}
if len(p.typIndex) != len(predecl) {
Fatalf("exporter: duplicate entries in type map?")
}
// write package data
if localpkg.Path != "" {
Fatalf("exporter: local package path not empty: %q", localpkg.Path)
}
p.pkg(localpkg)
if p.trace {
p.tracef("\n")
}
// export objects
//
// First, export all exported (package-level) objects; i.e., all objects
// in the current exportlist. These objects represent all information
// required to import this package and type-check against it; i.e., this
// is the platform-independent export data. The format is generic in the
// sense that different compilers can use the same representation.
//
// During this first phase, more objects may be added to the exportlist
// (due to inlined function bodies and their dependencies). Export those
// objects in a second phase. That data is platform-specific as it depends
// on the inlining decisions of the compiler and the representation of the
// inlined function bodies.
// remember initial exportlist length
var numglobals = len(exportlist)
// Phase 1: Export objects in _current_ exportlist; exported objects at
// package level.
// Use range since we want to ignore objects added to exportlist during
// this phase.
objcount := 0
for _, n := range exportlist {
sym := n.Sym
if sym.Flags&SymExported != 0 {
continue
}
sym.Flags |= SymExported
// TODO(gri) Closures have dots in their names;
// e.g., TestFloatZeroValue.func1 in math/big tests.
if strings.Contains(sym.Name, ".") {
Fatalf("exporter: unexpected symbol: %v", sym)
}
// TODO(gri) Should we do this check?
// if sym.Flags&SymExport == 0 {
// continue
// }
if sym.Def == nil {
Fatalf("exporter: unknown export symbol: %v", sym)
}
// TODO(gri) Optimization: Probably worthwhile collecting
// long runs of constants and export them "in bulk" (saving
// tags and types, and making import faster).
if p.trace {
p.tracef("\n")
}
p.obj(sym)
objcount++
}
// indicate end of list
if p.trace {
p.tracef("\n")
}
p.tag(endTag)
// for self-verification only (redundant)
p.int(objcount)
// --- compiler-specific export data ---
if p.trace {
p.tracef("\n--- compiler-specific export data ---\n[ ")
if p.indent != 0 {
Fatalf("exporter: incorrect indentation")
}
}
// write compiler-specific flags
if p.trace {
p.tracef("\n")
}
// Phase 2: Export objects added to exportlist during phase 1.
// Don't use range since exportlist may grow during this phase
// and we want to export all remaining objects.
objcount = 0
for i := numglobals; exportInlined && i < len(exportlist); i++ {
n := exportlist[i]
sym := n.Sym
// TODO(gri) The rest of this loop body is identical with
// the loop body above. Leave alone for now since there
// are different optimization opportunities, but factor
// eventually.
if sym.Flags&SymExported != 0 {
continue
}
sym.Flags |= SymExported
// TODO(gri) Closures have dots in their names;
// e.g., TestFloatZeroValue.func1 in math/big tests.
if strings.Contains(sym.Name, ".") {
Fatalf("exporter: unexpected symbol: %v", sym)
}
// TODO(gri) Should we do this check?
// if sym.Flags&SymExport == 0 {
// continue
// }
if sym.Def == nil {
Fatalf("exporter: unknown export symbol: %v", sym)
}
// TODO(gri) Optimization: Probably worthwhile collecting
// long runs of constants and export them "in bulk" (saving
// tags and types, and making import faster).
if p.trace {
p.tracef("\n")
}
p.obj(sym)
objcount++
}
// indicate end of list
if p.trace {
p.tracef("\n")
}
p.tag(endTag)
// for self-verification only (redundant)
p.int(objcount)
// --- inlined function bodies ---
if p.trace {
p.tracef("\n--- inlined function bodies ---\n")
if p.indent != 0 {
Fatalf("exporter: incorrect indentation")
}
}
// write inlineable function bodies
objcount = 0
for i, f := range p.funcList {
if f != nil {
// function has inlineable body:
// write index and body
if p.trace {
p.tracef("\n----\nfunc { %s }\n", hconv(f.Inl, FmtSharp))
}
p.int(i)
p.stmtList(f.Inl)
if p.trace {
p.tracef("\n")
}
objcount++
}
}
// indicate end of list
if p.trace {
p.tracef("\n")
}
p.int(-1) // invalid index terminates list
// for self-verification only (redundant)
p.int(objcount)
if p.trace {
p.tracef("\n--- end ---\n")
}
// --- end of export data ---
return p.written
}
func (p *exporter) pkg(pkg *Pkg) {
if pkg == nil {
Fatalf("exporter: unexpected nil pkg")
}
// if we saw the package before, write its index (>= 0)
if i, ok := p.pkgIndex[pkg]; ok {
p.index('P', i)
return
}
// otherwise, remember the package, write the package tag (< 0) and package data
if p.trace {
p.tracef("P%d = { ", len(p.pkgIndex))
defer p.tracef("} ")
}
p.pkgIndex[pkg] = len(p.pkgIndex)
p.tag(packageTag)
p.string(pkg.Name)
p.string(pkg.Path)
}
func unidealType(typ *Type, val Val) *Type {
// Untyped (ideal) constants get their own type. This decouples
// the constant type from the encoding of the constant value.
if typ == nil || typ.IsUntyped() {
typ = untype(val.Ctype())
}
return typ
}
func (p *exporter) obj(sym *Sym) {
// Exported objects may be from different packages because they
// may be re-exported as depencies when exporting inlined function
// bodies. Thus, exported object names must be fully qualified.
//
// TODO(gri) This can only happen if exportInlined is enabled
// (default), and during phase 2 of object export. Objects exported
// in phase 1 (compiler-indendepent objects) are by definition only
// the objects from the current package and not pulled in via inlined
// function bodies. In that case the package qualifier is not needed.
// Possible space optimization.
n := sym.Def
switch n.Op {
case OLITERAL:
// constant
// TODO(gri) determine if we need the typecheck call here
n = typecheck(n, Erv)
if n == nil || n.Op != OLITERAL {
Fatalf("exporter: dumpexportconst: oconst nil: %v", sym)
}
p.tag(constTag)
p.pos(n)
// TODO(gri) In inlined functions, constants are used directly
// so they should never occur as re-exported objects. We may
// not need the qualified name here. See also comment above.
// Possible space optimization.
p.qualifiedName(sym)
p.typ(unidealType(n.Type, n.Val()))
p.value(n.Val())
case OTYPE:
// named type
t := n.Type
if t.Etype == TFORW {
Fatalf("exporter: export of incomplete type %v", sym)
}
p.tag(typeTag)
p.typ(t)
case ONAME:
// variable or function
n = typecheck(n, Erv|Ecall)
if n == nil || n.Type == nil {
Fatalf("exporter: variable/function exported but not defined: %v", sym)
}
if n.Type.Etype == TFUNC && n.Class == PFUNC {
// function
p.tag(funcTag)
p.pos(n)
p.qualifiedName(sym)
sig := sym.Def.Type
inlineable := isInlineable(sym.Def)
p.paramList(sig.Params(), inlineable)
p.paramList(sig.Results(), inlineable)
var f *Func
if inlineable {
f = sym.Def.Func
// TODO(gri) re-examine reexportdeplist:
// Because we can trivially export types
// in-place, we don't need to collect types
// inside function bodies in the exportlist.
// With an adjusted reexportdeplist used only
// by the binary exporter, we can also avoid
// the global exportlist.
reexportdeplist(f.Inl)
}
p.funcList = append(p.funcList, f)
} else {
// variable
p.tag(varTag)
p.pos(n)
p.qualifiedName(sym)
p.typ(sym.Def.Type)
}
default:
Fatalf("exporter: unexpected export symbol: %v %v", n.Op, sym)
}
}
func (p *exporter) pos(n *Node) {
if !p.posInfoFormat {
return
}
file, line := fileLine(n)
if file == p.prevFile {
// common case: write line delta
// delta == 0 means different file or no line change
delta := line - p.prevLine
p.int(delta)
if delta == 0 {
p.int(-1) // -1 means no file change
}
} else {
// different file
p.int(0)
// Encode filename as length of common prefix with previous
// filename, followed by (possibly empty) suffix. Filenames
// frequently share path prefixes, so this can save a lot
// of space and make export data size less dependent on file
// path length. The suffix is unlikely to be empty because
// file names tend to end in ".go".
n := commonPrefixLen(p.prevFile, file)
p.int(n) // n >= 0
p.string(file[n:]) // write suffix only
p.prevFile = file
p.int(line)
}
p.prevLine = line
}
func fileLine(n *Node) (file string, line int) {
if n != nil {
file, line = Ctxt.LineHist.AbsFileLine(int(n.Lineno))
}
return
}
func commonPrefixLen(a, b string) int {
if len(a) > len(b) {
a, b = b, a
}
// len(a) <= len(b)
i := 0
for i < len(a) && a[i] == b[i] {
i++
}
return i
}
func isInlineable(n *Node) bool {
if exportInlined && n != nil && n.Func != nil && n.Func.Inl.Len() != 0 {
// when lazily typechecking inlined bodies, some re-exported ones may not have been typechecked yet.
// currently that can leave unresolved ONONAMEs in import-dot-ed packages in the wrong package
if Debug['l'] < 2 {
typecheckinl(n)
}
return true
}
return false
}
var errorInterface *Type // lazily initialized
func (p *exporter) typ(t *Type) {
if t == nil {
Fatalf("exporter: nil type")
}
// Possible optimization: Anonymous pointer types *T where
// T is a named type are common. We could canonicalize all
// such types *T to a single type PT = *T. This would lead
// to at most one *T entry in typIndex, and all future *T's
// would be encoded as the respective index directly. Would
// save 1 byte (pointerTag) per *T and reduce the typIndex
// size (at the cost of a canonicalization map). We can do
// this later, without encoding format change.
// if we saw the type before, write its index (>= 0)
if i, ok := p.typIndex[t]; ok {
p.index('T', i)
return
}
// otherwise, remember the type, write the type tag (< 0) and type data
if trackAllTypes {
if p.trace {
p.tracef("T%d = {>\n", len(p.typIndex))
defer p.tracef("<\n} ")
}
p.typIndex[t] = len(p.typIndex)
}
// pick off named types
if tsym := t.Sym; tsym != nil {
if !trackAllTypes {
// if we don't track all types, track named types now
p.typIndex[t] = len(p.typIndex)
}
// Predeclared types should have been found in the type map.
if t.Orig == t {
Fatalf("exporter: predeclared type missing from type map?")
}
n := typenod(t)
if n.Type != t {
Fatalf("exporter: named type definition incorrectly set up")
}
p.tag(namedTag)
p.pos(n)
p.qualifiedName(tsym)
// write underlying type
orig := t.Orig
if orig == errortype {
// The error type is the only predeclared type which has
// a composite underlying type. When we encode that type,
// make sure to encode the underlying interface rather than
// the named type again. See also the comment in universe.go
// regarding the errortype and issue #15920.
if errorInterface == nil {
errorInterface = makeErrorInterface()
}
orig = errorInterface
}
p.typ(orig)
// interfaces don't have associated methods
if t.Orig.IsInterface() {
return
}
// sort methods for reproducible export format
// TODO(gri) Determine if they are already sorted
// in which case we can drop this step.
var methods []*Field
for _, m := range t.Methods().Slice() {
methods = append(methods, m)
}
sort.Sort(methodbyname(methods))
p.int(len(methods))
if p.trace && len(methods) > 0 {
p.tracef("associated methods {>")
}
for _, m := range methods {
if p.trace {
p.tracef("\n")
}
if strings.Contains(m.Sym.Name, ".") {
Fatalf("invalid symbol name: %s (%v)", m.Sym.Name, m.Sym)
}
p.pos(m.Nname)
p.fieldSym(m.Sym, false)
sig := m.Type
mfn := sig.Nname()
inlineable := isInlineable(mfn)
p.paramList(sig.Recvs(), inlineable)
p.paramList(sig.Params(), inlineable)
p.paramList(sig.Results(), inlineable)
p.bool(m.Nointerface) // record go:nointerface pragma value (see also #16243)
var f *Func
if inlineable {
f = mfn.Func
reexportdeplist(mfn.Func.Inl)
}
p.funcList = append(p.funcList, f)
}
if p.trace && len(methods) > 0 {
p.tracef("<\n} ")
}
return
}
// otherwise we have a type literal
switch t.Etype {
case TARRAY:
if t.isDDDArray() {
Fatalf("array bounds should be known at export time: %v", t)
}
p.tag(arrayTag)
p.int64(t.NumElem())
p.typ(t.Elem())
case TSLICE:
p.tag(sliceTag)
p.typ(t.Elem())
case TDDDFIELD:
// see p.param use of TDDDFIELD
p.tag(dddTag)
p.typ(t.DDDField())
case TSTRUCT:
p.tag(structTag)
p.fieldList(t)
case TPTR32, TPTR64: // could use Tptr but these are constants
p.tag(pointerTag)
p.typ(t.Elem())
case TFUNC:
p.tag(signatureTag)
p.paramList(t.Params(), false)
p.paramList(t.Results(), false)
case TINTER:
p.tag(interfaceTag)
// gc doesn't separate between embedded interfaces
// and methods declared explicitly with an interface
p.int(0) // no embedded interfaces
// Because the compiler flattens interfaces containing
// embedded interfaces, it is possible to create interface
// types that recur through an unnamed type.
// If trackAllTypes is disabled, such recursion is not
// detected, leading to a stack overflow during export
// (issue #16369).
// As a crude work-around we terminate deep recursion
// through interface types with an empty interface and
// report an error.
// This will catch endless recursion, but is unlikely
// to trigger for valid, deeply nested types given the
// high threshold.
// It would be ok to continue without reporting an error
// since the export format is valid. But a subsequent
// import would import an incorrect type. The textual
// exporter does not report an error but importing the
// resulting package will lead to a syntax error during
// import.
// TODO(gri) remove this once we have a permanent fix
// for the issue.
if p.nesting > 100 {
p.int(0) // 0 methods to indicate empty interface
yyerrorl(t.Lineno, "cannot export unnamed recursive interface")
break
}
p.nesting++
p.methodList(t)
p.nesting--
case TMAP:
p.tag(mapTag)
p.typ(t.Key())
p.typ(t.Val())
case TCHAN:
p.tag(chanTag)
p.int(int(t.ChanDir()))
p.typ(t.Elem())
default:
Fatalf("exporter: unexpected type: %s (Etype = %d)", Tconv(t, 0), t.Etype)
}
}
func (p *exporter) qualifiedName(sym *Sym) {
p.string(sym.Name)
p.pkg(sym.Pkg)
}
func (p *exporter) fieldList(t *Type) {
if p.trace && t.NumFields() > 0 {
p.tracef("fields {>")
defer p.tracef("<\n} ")
}
p.int(t.NumFields())
for _, f := range t.Fields().Slice() {
if p.trace {
p.tracef("\n")
}
p.field(f)
}
}
func (p *exporter) field(f *Field) {
p.pos(f.Nname)
p.fieldName(f)
p.typ(f.Type)
p.string(f.Note)
}
func (p *exporter) methodList(t *Type) {
if p.trace && t.NumFields() > 0 {
p.tracef("methods {>")
defer p.tracef("<\n} ")
}
p.int(t.NumFields())
for _, m := range t.Fields().Slice() {
if p.trace {
p.tracef("\n")
}
p.method(m)
}
}
func (p *exporter) method(m *Field) {
p.pos(m.Nname)
p.fieldName(m)
p.paramList(m.Type.Params(), false)
p.paramList(m.Type.Results(), false)
}
// fieldName is like qualifiedName but it doesn't record the package for exported names.
func (p *exporter) fieldName(t *Field) {
name := t.Sym.Name
if t.Embedded != 0 {
name = "" // anonymous field
if bname := basetypeName(t.Type); bname != "" && !exportname(bname) {
// anonymous field with unexported base type name
name = "?" // unexported name to force export of package
}
}
p.string(name)
if name != "" && !exportname(name) {
p.pkg(t.Sym.Pkg)
}
}
func basetypeName(t *Type) string {
s := t.Sym
if s == nil && t.IsPtr() {
s = t.Elem().Sym // deref
}
// s should exist, but be conservative
if s != nil {
return s.Name
}
return ""
}
func (p *exporter) paramList(params *Type, numbered bool) {
if !params.IsFuncArgStruct() {
Fatalf("exporter: parameter list expected")
}
// use negative length to indicate unnamed parameters
// (look at the first parameter only since either all
// names are present or all are absent)
//
// TODO(gri) If we don't have an exported function
// body, the parameter names are irrelevant for the
// compiler (though they may be of use for other tools).
// Possible space optimization.
n := params.NumFields()
if n > 0 && parName(params.Field(0), numbered) == "" {
n = -n
}
p.int(n)
for _, q := range params.Fields().Slice() {
p.param(q, n, numbered)
}
}
func (p *exporter) param(q *Field, n int, numbered bool) {
t := q.Type
if q.Isddd {
// create a fake type to encode ... just for the p.typ call
t = typDDDField(t.Elem())
}
p.typ(t)
if n > 0 {
name := parName(q, numbered)
if name == "" {
// Sometimes we see an empty name even for n > 0.
// This appears to happen for interface methods
// with _ (blank) parameter names. Make sure we
// have a proper name and package so we don't crash
// during import (see also issue #15470).
// (parName uses "" instead of "?" as in fmt.go)
// TODO(gri) review parameter name encoding
name = "_"
}
p.string(name)
if name != "_" {
// Because of (re-)exported inlined functions
// the importpkg may not be the package to which this
// function (and thus its parameter) belongs. We need to
// supply the parameter package here. We need the package
// when the function is inlined so we can properly resolve
// the name. The _ (blank) parameter cannot be accessed, so
// we don't need to export a package.
//
// TODO(gri) This is compiler-specific. Try using importpkg
// here and then update the symbols if we find an inlined
// body only. Otherwise, the parameter name is ignored and
// the package doesn't matter. This would remove an int
// (likely 1 byte) for each named parameter.
p.pkg(q.Sym.Pkg)
}
}
// TODO(gri) This is compiler-specific (escape info).
// Move into compiler-specific section eventually?
// (Not having escape info causes tests to fail, e.g. runtime GCInfoTest)
p.string(q.Note)
}
func parName(f *Field, numbered bool) string {
s := f.Sym
if s == nil {
return ""
}
// Take the name from the original, lest we substituted it with ~r%d or ~b%d.
// ~r%d is a (formerly) unnamed result.
if f.Nname != nil {
if f.Nname.Orig != nil {
s = f.Nname.Orig.Sym
if s != nil && s.Name[0] == '~' {
if s.Name[1] == 'r' { // originally an unnamed result
return "" // s = nil
} else if s.Name[1] == 'b' { // originally the blank identifier _
return "_" // belongs to localpkg
}
}
} else {
return "" // s = nil
}
}
if s == nil {
return ""
}
// print symbol with Vargen number or not as desired
name := s.Name
if strings.Contains(name, ".") {
Fatalf("invalid symbol name: %s", name)
}
// Functions that can be inlined use numbered parameters so we can distingish them
// from other names in their context after inlining (i.e., the parameter numbering
// is a form of parameter rewriting). See issue 4326 for an example and test case.
if forceObjFileStability || numbered {
if !strings.Contains(name, "·") && f.Nname != nil && f.Nname.Name != nil && f.Nname.Name.Vargen > 0 {
name = fmt.Sprintf("%s·%d", name, f.Nname.Name.Vargen) // append Vargen
}
} else {
if i := strings.Index(name, "·"); i > 0 {
name = name[:i] // cut off Vargen
}