data.go (6540B)
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 (forsyth@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@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 "github.com/twitchyliquid64/golang-asm/objabi" 36 "log" 37 "math" 38 ) 39 40 // Grow increases the length of s.P to lsiz. 41 func (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. 53 func (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. 67 func (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. 87 func (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. 93 func (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. 99 func (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 } 114 115 func (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. 134 func (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 // WriteCURelativeAddr writes a pointer-sized address into s at offset off. 139 // rsym and roff specify the relocation for the address which will be 140 // resolved by the linker to an offset from the DW_AT_low_pc attribute of 141 // the DWARF Compile Unit of rsym. 142 func (s *LSym) WriteCURelativeAddr(ctxt *Link, off int64, rsym *LSym, roff int64) { 143 s.writeAddr(ctxt, off, ctxt.Arch.PtrSize, rsym, roff, objabi.R_ADDRCUOFF) 144 } 145 146 // WriteOff writes a 4 byte offset to rsym+roff into s at offset off. 147 // After linking the 4 bytes stored at s+off will be 148 // rsym+roff-(start of section that s is in). 149 func (s *LSym) WriteOff(ctxt *Link, off int64, rsym *LSym, roff int64) { 150 s.prepwrite(ctxt, off, 4) 151 r := Addrel(s) 152 r.Off = int32(off) 153 if int64(r.Off) != off { 154 ctxt.Diag("WriteOff: off overflow %d in %s", off, s.Name) 155 } 156 r.Siz = 4 157 r.Sym = rsym 158 r.Type = objabi.R_ADDROFF 159 r.Add = roff 160 } 161 162 // WriteWeakOff writes a weak 4 byte offset to rsym+roff into s at offset off. 163 // After linking the 4 bytes stored at s+off will be 164 // rsym+roff-(start of section that s is in). 165 func (s *LSym) WriteWeakOff(ctxt *Link, off int64, rsym *LSym, roff int64) { 166 s.prepwrite(ctxt, off, 4) 167 r := Addrel(s) 168 r.Off = int32(off) 169 if int64(r.Off) != off { 170 ctxt.Diag("WriteOff: off overflow %d in %s", off, s.Name) 171 } 172 r.Siz = 4 173 r.Sym = rsym 174 r.Type = objabi.R_WEAKADDROFF 175 r.Add = roff 176 } 177 178 // WriteString writes a string of size siz into s at offset off. 179 func (s *LSym) WriteString(ctxt *Link, off int64, siz int, str string) { 180 if siz < len(str) { 181 ctxt.Diag("WriteString: bad string size: %d < %d", siz, len(str)) 182 } 183 s.prepwrite(ctxt, off, siz) 184 copy(s.P[off:off+int64(siz)], str) 185 } 186 187 // WriteBytes writes a slice of bytes into s at offset off. 188 func (s *LSym) WriteBytes(ctxt *Link, off int64, b []byte) int64 { 189 s.prepwrite(ctxt, off, len(b)) 190 copy(s.P[off:], b) 191 return off + int64(len(b)) 192 } 193 194 func Addrel(s *LSym) *Reloc { 195 if s.R == nil { 196 s.R = make([]Reloc, 0, 4) 197 } 198 s.R = append(s.R, Reloc{}) 199 return &s.R[len(s.R)-1] 200 }