1// Derived from Inferno utils/6l/obj.c and utils/6l/span.c
2// https://bitbucket.org/inferno-os/inferno-os/src/master/utils/6l/obj.c
3// https://bitbucket.org/inferno-os/inferno-os/src/master/utils/6l/span.c
4//
5//	Copyright © 1994-1999 Lucent Technologies Inc.  All rights reserved.
6//	Portions Copyright © 1995-1997 C H Forsyth ([email protected])
7//	Portions Copyright © 1997-1999 Vita Nuova Limited
8//	Portions Copyright © 2000-2007 Vita Nuova Holdings Limited (www.vitanuova.com)
9//	Portions Copyright © 2004,2006 Bruce Ellis
10//	Portions Copyright © 2005-2007 C H Forsyth ([email protected])
11//	Revisions Copyright © 2000-2007 Lucent Technologies Inc. and others
12//	Portions Copyright © 2009 The Go Authors. All rights reserved.
13//
14// Permission is hereby granted, free of charge, to any person obtaining a copy
15// of this software and associated documentation files (the "Software"), to deal
16// in the Software without restriction, including without limitation the rights
17// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
18// copies of the Software, and to permit persons to whom the Software is
19// furnished to do so, subject to the following conditions:
20//
21// The above copyright notice and this permission notice shall be included in
22// all copies or substantial portions of the Software.
23//
24// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
25// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
26// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
27// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
28// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
29// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
30// THE SOFTWARE.
31
32package obj
33
34import (
35	"cmd/internal/objabi"
36	"log"
37	"math"
38)
39
40// Grow increases the length of s.P to lsiz.
41func (s *LSym) Grow(lsiz int64) {
42	siz := int(lsiz)
43	if int64(siz) != lsiz {
44		log.Fatalf("LSym.Grow size %d too long", lsiz)
45	}
46	if len(s.P) >= siz {
47		return
48	}
49	s.P = append(s.P, make([]byte, siz-len(s.P))...)
50}
51
52// GrowCap increases the capacity of s.P to c.
53func (s *LSym) GrowCap(c int64) {
54	if int64(cap(s.P)) >= c {
55		return
56	}
57	if s.P == nil {
58		s.P = make([]byte, 0, c)
59		return
60	}
61	b := make([]byte, len(s.P), c)
62	copy(b, s.P)
63	s.P = b
64}
65
66// prepwrite prepares to write data of size siz into s at offset off.
67func (s *LSym) prepwrite(ctxt *Link, off int64, siz int) {
68	if off < 0 || siz < 0 || off >= 1<<30 {
69		ctxt.Diag("prepwrite: bad off=%d siz=%d s=%v", off, siz, s)
70	}
71	switch s.Type {
72	case objabi.Sxxx, objabi.SBSS:
73		s.Type = objabi.SDATA
74	case objabi.SNOPTRBSS:
75		s.Type = objabi.SNOPTRDATA
76	case objabi.STLSBSS:
77		ctxt.Diag("cannot supply data for %v var %v", s.Type, s.Name)
78	}
79	l := off + int64(siz)
80	s.Grow(l)
81	if l > s.Size {
82		s.Size = l
83	}
84}
85
86// WriteFloat32 writes f into s at offset off.
87func (s *LSym) WriteFloat32(ctxt *Link, off int64, f float32) {
88	s.prepwrite(ctxt, off, 4)
89	ctxt.Arch.ByteOrder.PutUint32(s.P[off:], math.Float32bits(f))
90}
91
92// WriteFloat64 writes f into s at offset off.
93func (s *LSym) WriteFloat64(ctxt *Link, off int64, f float64) {
94	s.prepwrite(ctxt, off, 8)
95	ctxt.Arch.ByteOrder.PutUint64(s.P[off:], math.Float64bits(f))
96}
97
98// WriteInt writes an integer i of size siz into s at offset off.
99func (s *LSym) WriteInt(ctxt *Link, off int64, siz int, i int64) {
100	s.prepwrite(ctxt, off, siz)
101	switch siz {
102	default:
103		ctxt.Diag("WriteInt: bad integer size: %d", siz)
104	case 1:
105		s.P[off] = byte(i)
106	case 2:
107		ctxt.Arch.ByteOrder.PutUint16(s.P[off:], uint16(i))
108	case 4:
109		ctxt.Arch.ByteOrder.PutUint32(s.P[off:], uint32(i))
110	case 8:
111		ctxt.Arch.ByteOrder.PutUint64(s.P[off:], uint64(i))
112	}
113}
114
115func (s *LSym) writeAddr(ctxt *Link, off int64, siz int, rsym *LSym, roff int64, rtype objabi.RelocType) {
116	// Allow 4-byte addresses for DWARF.
117	if siz != ctxt.Arch.PtrSize && siz != 4 {
118		ctxt.Diag("WriteAddr: bad address size %d in %s", siz, s.Name)
119	}
120	s.prepwrite(ctxt, off, siz)
121	r := Addrel(s)
122	r.Off = int32(off)
123	if int64(r.Off) != off {
124		ctxt.Diag("WriteAddr: off overflow %d in %s", off, s.Name)
125	}
126	r.Siz = uint8(siz)
127	r.Sym = rsym
128	r.Type = rtype
129	r.Add = roff
130}
131
132// WriteAddr writes an address of size siz into s at offset off.
133// rsym and roff specify the relocation for the address.
134func (s *LSym) WriteAddr(ctxt *Link, off int64, siz int, rsym *LSym, roff int64) {
135	s.writeAddr(ctxt, off, siz, rsym, roff, objabi.R_ADDR)
136}
137
138// WriteWeakAddr writes an address of size siz into s at offset off.
139// rsym and roff specify the relocation for the address.
140// This is a weak reference.
141func (s *LSym) WriteWeakAddr(ctxt *Link, off int64, siz int, rsym *LSym, roff int64) {
142	s.writeAddr(ctxt, off, siz, rsym, roff, objabi.R_WEAKADDR)
143}
144
145// WriteCURelativeAddr writes a pointer-sized address into s at offset off.
146// rsym and roff specify the relocation for the address which will be
147// resolved by the linker to an offset from the DW_AT_low_pc attribute of
148// the DWARF Compile Unit of rsym.
149func (s *LSym) WriteCURelativeAddr(ctxt *Link, off int64, rsym *LSym, roff int64) {
150	s.writeAddr(ctxt, off, ctxt.Arch.PtrSize, rsym, roff, objabi.R_ADDRCUOFF)
151}
152
153// WriteOff writes a 4 byte offset to rsym+roff into s at offset off.
154// After linking the 4 bytes stored at s+off will be
155// rsym+roff-(start of section that s is in).
156func (s *LSym) WriteOff(ctxt *Link, off int64, rsym *LSym, roff int64) {
157	s.prepwrite(ctxt, off, 4)
158	r := Addrel(s)
159	r.Off = int32(off)
160	if int64(r.Off) != off {
161		ctxt.Diag("WriteOff: off overflow %d in %s", off, s.Name)
162	}
163	r.Siz = 4
164	r.Sym = rsym
165	r.Type = objabi.R_ADDROFF
166	r.Add = roff
167}
168
169// WriteWeakOff writes a weak 4 byte offset to rsym+roff into s at offset off.
170// After linking the 4 bytes stored at s+off will be
171// rsym+roff-(start of section that s is in).
172func (s *LSym) WriteWeakOff(ctxt *Link, off int64, rsym *LSym, roff int64) {
173	s.prepwrite(ctxt, off, 4)
174	r := Addrel(s)
175	r.Off = int32(off)
176	if int64(r.Off) != off {
177		ctxt.Diag("WriteOff: off overflow %d in %s", off, s.Name)
178	}
179	r.Siz = 4
180	r.Sym = rsym
181	r.Type = objabi.R_WEAKADDROFF
182	r.Add = roff
183}
184
185// WriteString writes a string of size siz into s at offset off.
186func (s *LSym) WriteString(ctxt *Link, off int64, siz int, str string) {
187	if siz < len(str) {
188		ctxt.Diag("WriteString: bad string size: %d < %d", siz, len(str))
189	}
190	s.prepwrite(ctxt, off, siz)
191	copy(s.P[off:off+int64(siz)], str)
192}
193
194// WriteBytes writes a slice of bytes into s at offset off.
195func (s *LSym) WriteBytes(ctxt *Link, off int64, b []byte) int64 {
196	s.prepwrite(ctxt, off, len(b))
197	copy(s.P[off:], b)
198	return off + int64(len(b))
199}
200
201func Addrel(s *LSym) *Reloc {
202	if s.R == nil {
203		s.R = make([]Reloc, 0, 4)
204	}
205	s.R = append(s.R, Reloc{})
206	return &s.R[len(s.R)-1]
207}
208