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      1 // Derived from Inferno utils/6l/obj.c and utils/6l/span.c
      2 // https://bitbucket.org/inferno-os/inferno-os/src/default/utils/6l/obj.c
      3 // https://bitbucket.org/inferno-os/inferno-os/src/default/utils/6l/span.c
      4 //
      5 //	Copyright  1994-1999 Lucent Technologies Inc.  All rights reserved.
      6 //	Portions Copyright  1995-1997 C H Forsyth (forsyth (a] terzarima.net)
      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 (forsyth (a] terzarima.net)
     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 
     32 package obj
     33 
     34 import (
     35 	"log"
     36 	"math"
     37 )
     38 
     39 // Grow increases the length of s.P to lsiz.
     40 func (s *LSym) Grow(lsiz int64) {
     41 	siz := int(lsiz)
     42 	if int64(siz) != lsiz {
     43 		log.Fatalf("LSym.Grow size %d too long", lsiz)
     44 	}
     45 	if len(s.P) >= siz {
     46 		return
     47 	}
     48 	// TODO(dfc) append cap-len at once, rather than
     49 	// one byte at a time.
     50 	for cap(s.P) < siz {
     51 		s.P = append(s.P[:cap(s.P)], 0)
     52 	}
     53 	s.P = s.P[:siz]
     54 }
     55 
     56 // GrowCap increases the capacity of s.P to c.
     57 func (s *LSym) GrowCap(c int64) {
     58 	if int64(cap(s.P)) >= c {
     59 		return
     60 	}
     61 	if s.P == nil {
     62 		s.P = make([]byte, 0, c)
     63 		return
     64 	}
     65 	b := make([]byte, len(s.P), c)
     66 	copy(b, s.P)
     67 	s.P = b
     68 }
     69 
     70 // prepwrite prepares to write data of size siz into s at offset off.
     71 func (s *LSym) prepwrite(ctxt *Link, off int64, siz int) {
     72 	if off < 0 || siz < 0 || off >= 1<<30 {
     73 		log.Fatalf("prepwrite: bad off=%d siz=%d", off, siz)
     74 	}
     75 	if s.Type == SBSS || s.Type == STLSBSS {
     76 		ctxt.Diag("cannot supply data for BSS var")
     77 	}
     78 	l := off + int64(siz)
     79 	s.Grow(l)
     80 	if l > s.Size {
     81 		s.Size = l
     82 	}
     83 }
     84 
     85 // WriteFloat32 writes f into s at offset off.
     86 func (s *LSym) WriteFloat32(ctxt *Link, off int64, f float32) {
     87 	s.prepwrite(ctxt, off, 4)
     88 	ctxt.Arch.ByteOrder.PutUint32(s.P[off:], math.Float32bits(f))
     89 }
     90 
     91 // WriteFloat64 writes f into s at offset off.
     92 func (s *LSym) WriteFloat64(ctxt *Link, off int64, f float64) {
     93 	s.prepwrite(ctxt, off, 8)
     94 	ctxt.Arch.ByteOrder.PutUint64(s.P[off:], math.Float64bits(f))
     95 }
     96 
     97 // WriteInt writes an integer i of size siz into s at offset off.
     98 func (s *LSym) WriteInt(ctxt *Link, off int64, siz int, i int64) {
     99 	s.prepwrite(ctxt, off, siz)
    100 	switch siz {
    101 	default:
    102 		ctxt.Diag("WriteInt: bad integer size: %d", siz)
    103 	case 1:
    104 		s.P[off] = byte(i)
    105 	case 2:
    106 		ctxt.Arch.ByteOrder.PutUint16(s.P[off:], uint16(i))
    107 	case 4:
    108 		ctxt.Arch.ByteOrder.PutUint32(s.P[off:], uint32(i))
    109 	case 8:
    110 		ctxt.Arch.ByteOrder.PutUint64(s.P[off:], uint64(i))
    111 	}
    112 }
    113 
    114 // WriteAddr writes an address of size siz into s at offset off.
    115 // rsym and roff specify the relocation for the address.
    116 func (s *LSym) WriteAddr(ctxt *Link, off int64, siz int, rsym *LSym, roff int64) {
    117 	if siz != ctxt.Arch.PtrSize {
    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 = R_ADDR
    129 	r.Add = roff
    130 }
    131 
    132 // WriteOff writes a 4 byte offset to rsym+roff into s at offset off.
    133 // After linking the 4 bytes stored at s+off will be
    134 // rsym+roff-(start of section that s is in).
    135 func (s *LSym) WriteOff(ctxt *Link, off int64, rsym *LSym, roff int64) {
    136 	s.prepwrite(ctxt, off, 4)
    137 	r := Addrel(s)
    138 	r.Off = int32(off)
    139 	if int64(r.Off) != off {
    140 		ctxt.Diag("WriteOff: off overflow %d in %s", off, s.Name)
    141 	}
    142 	r.Siz = 4
    143 	r.Sym = rsym
    144 	r.Type = R_ADDROFF
    145 	r.Add = roff
    146 }
    147 
    148 // WriteWeakOff writes a weak 4 byte offset to rsym+roff into s at offset off.
    149 // After linking the 4 bytes stored at s+off will be
    150 // rsym+roff-(start of section that s is in).
    151 func (s *LSym) WriteWeakOff(ctxt *Link, off int64, rsym *LSym, roff int64) {
    152 	s.prepwrite(ctxt, off, 4)
    153 	r := Addrel(s)
    154 	r.Off = int32(off)
    155 	if int64(r.Off) != off {
    156 		ctxt.Diag("WriteOff: off overflow %d in %s", off, s.Name)
    157 	}
    158 	r.Siz = 4
    159 	r.Sym = rsym
    160 	r.Type = R_WEAKADDROFF
    161 	r.Add = roff
    162 }
    163 
    164 // WriteString writes a string of size siz into s at offset off.
    165 func (s *LSym) WriteString(ctxt *Link, off int64, siz int, str string) {
    166 	if siz < len(str) {
    167 		ctxt.Diag("WriteString: bad string size: %d < %d", siz, len(str))
    168 	}
    169 	s.prepwrite(ctxt, off, siz)
    170 	copy(s.P[off:off+int64(siz)], str)
    171 }
    172 
    173 // WriteBytes writes a slice of bytes into s at offset off.
    174 func (s *LSym) WriteBytes(ctxt *Link, off int64, b []byte) int64 {
    175 	s.prepwrite(ctxt, off, len(b))
    176 	copy(s.P[off:], b)
    177 	return off + int64(len(b))
    178 }
    179 
    180 func Addrel(s *LSym) *Reloc {
    181 	s.R = append(s.R, Reloc{})
    182 	return &s.R[len(s.R)-1]
    183 }
    184 
    185 func Setuintxx(ctxt *Link, s *LSym, off int64, v uint64, wid int64) int64 {
    186 	if s.Type == 0 {
    187 		s.Type = SDATA
    188 	}
    189 	if s.Size < off+wid {
    190 		s.Size = off + wid
    191 		s.Grow(s.Size)
    192 	}
    193 
    194 	switch wid {
    195 	case 1:
    196 		s.P[off] = uint8(v)
    197 	case 2:
    198 		ctxt.Arch.ByteOrder.PutUint16(s.P[off:], uint16(v))
    199 	case 4:
    200 		ctxt.Arch.ByteOrder.PutUint32(s.P[off:], uint32(v))
    201 	case 8:
    202 		ctxt.Arch.ByteOrder.PutUint64(s.P[off:], v)
    203 	}
    204 
    205 	return off + wid
    206 }
    207