aboutsummaryrefslogtreecommitdiff
path: root/src/cmd/link/internal/sym/symkind.go
blob: 9a1f33c582815442e145b86a6afddd50b17e387e (plain)
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
// Derived from Inferno utils/6l/l.h and related files.
// https://bitbucket.org/inferno-os/inferno-os/src/master/utils/6l/l.h
//
//	Copyright © 1994-1999 Lucent Technologies Inc.  All rights reserved.
//	Portions Copyright © 1995-1997 C H Forsyth (forsyth@terzarima.net)
//	Portions Copyright © 1997-1999 Vita Nuova Limited
//	Portions Copyright © 2000-2007 Vita Nuova Holdings Limited (www.vitanuova.com)
//	Portions Copyright © 2004,2006 Bruce Ellis
//	Portions Copyright © 2005-2007 C H Forsyth (forsyth@terzarima.net)
//	Revisions Copyright © 2000-2007 Lucent Technologies Inc. and others
//	Portions Copyright © 2009 The Go Authors. All rights reserved.
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.

package sym

import "cmd/internal/objabi"

// A SymKind describes the kind of memory represented by a symbol.
type SymKind uint8

// Defined SymKind values.
//
// TODO(rsc): Give idiomatic Go names.
//
//go:generate stringer -type=SymKind
const (
	Sxxx SymKind = iota
	STEXT
	SELFRXSECT
	SMACHOPLT

	// Read-only sections.
	STYPE
	SSTRING
	SGOSTRING
	SGOFUNC
	SGCBITS
	SRODATA
	SFUNCTAB

	SELFROSECT

	// Read-only sections with relocations.
	//
	// Types STYPE-SFUNCTAB above are written to the .rodata section by default.
	// When linking a shared object, some conceptually "read only" types need to
	// be written to by relocations and putting them in a section called
	// ".rodata" interacts poorly with the system linkers. The GNU linkers
	// support this situation by arranging for sections of the name
	// ".data.rel.ro.XXX" to be mprotected read only by the dynamic linker after
	// relocations have applied, so when the Go linker is creating a shared
	// object it checks all objects of the above types and bumps any object that
	// has a relocation to it to the corresponding type below, which are then
	// written to sections with appropriate magic names.
	STYPERELRO
	SSTRINGRELRO
	SGOSTRINGRELRO
	SGOFUNCRELRO
	SGCBITSRELRO
	SRODATARELRO
	SFUNCTABRELRO
	SELFRELROSECT

	// Part of .data.rel.ro if it exists, otherwise part of .rodata.
	STYPELINK
	SITABLINK
	SSYMTAB
	SPCLNTAB

	// Writable sections.
	SFirstWritable
	SBUILDINFO
	SELFSECT
	SMACHO
	SMACHOGOT
	SWINDOWS
	SELFGOT
	SNOPTRDATA
	SINITARR
	SDATA
	SXCOFFTOC
	SBSS
	SNOPTRBSS
	SLIBFUZZER_8BIT_COUNTER
	SCOVERAGE_COUNTER
	SCOVERAGE_AUXVAR
	STLSBSS
	SXREF
	SMACHOSYMSTR
	SMACHOSYMTAB
	SMACHOINDIRECTPLT
	SMACHOINDIRECTGOT
	SFILEPATH
	SDYNIMPORT
	SHOSTOBJ
	SUNDEFEXT // Undefined symbol for resolution by external linker

	// Sections for debugging information
	SDWARFSECT
	// DWARF symbol types
	SDWARFCUINFO
	SDWARFCONST
	SDWARFFCN
	SDWARFABSFCN
	SDWARFTYPE
	SDWARFVAR
	SDWARFRANGE
	SDWARFLOC
	SDWARFLINES

	// SEH symbol types
	SSEHUNWINDINFO
	SSEHSECT
)

// AbiSymKindToSymKind maps values read from object files (which are
// of type cmd/internal/objabi.SymKind) to values of type SymKind.
var AbiSymKindToSymKind = [...]SymKind{
	objabi.Sxxx:                    Sxxx,
	objabi.STEXT:                   STEXT,
	objabi.SRODATA:                 SRODATA,
	objabi.SNOPTRDATA:              SNOPTRDATA,
	objabi.SDATA:                   SDATA,
	objabi.SBSS:                    SBSS,
	objabi.SNOPTRBSS:               SNOPTRBSS,
	objabi.STLSBSS:                 STLSBSS,
	objabi.SDWARFCUINFO:            SDWARFCUINFO,
	objabi.SDWARFCONST:             SDWARFCONST,
	objabi.SDWARFFCN:               SDWARFFCN,
	objabi.SDWARFABSFCN:            SDWARFABSFCN,
	objabi.SDWARFTYPE:              SDWARFTYPE,
	objabi.SDWARFVAR:               SDWARFVAR,
	objabi.SDWARFRANGE:             SDWARFRANGE,
	objabi.SDWARFLOC:               SDWARFLOC,
	objabi.SDWARFLINES:             SDWARFLINES,
	objabi.SLIBFUZZER_8BIT_COUNTER: SLIBFUZZER_8BIT_COUNTER,
	objabi.SCOVERAGE_COUNTER:       SCOVERAGE_COUNTER,
	objabi.SCOVERAGE_AUXVAR:        SCOVERAGE_AUXVAR,
	objabi.SSEHUNWINDINFO:          SSEHUNWINDINFO,
}

// ReadOnly are the symbol kinds that form read-only sections. In some
// cases, if they will require relocations, they are transformed into
// rel-ro sections using relROMap.
var ReadOnly = []SymKind{
	STYPE,
	SSTRING,
	SGOSTRING,
	SGOFUNC,
	SGCBITS,
	SRODATA,
	SFUNCTAB,
}

// RelROMap describes the transformation of read-only symbols to rel-ro
// symbols.
var RelROMap = map[SymKind]SymKind{
	STYPE:     STYPERELRO,
	SSTRING:   SSTRINGRELRO,
	SGOSTRING: SGOSTRINGRELRO,
	SGOFUNC:   SGOFUNCRELRO,
	SGCBITS:   SGCBITSRELRO,
	SRODATA:   SRODATARELRO,
	SFUNCTAB:  SFUNCTABRELRO,
}

// IsData returns true if the type is a data type.
func (t SymKind) IsData() bool {
	return t == SDATA || t == SNOPTRDATA || t == SBSS || t == SNOPTRBSS
}

func (t SymKind) IsDWARF() bool {
	return t >= SDWARFSECT && t <= SDWARFLINES
}