github.com/go-asm/go@v1.21.1-0.20240213172139-40c5ead50c48/cmd/obj/data.go (about) 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 "log" 36 "math" 37 38 "github.com/go-asm/go/cmd/objabi" 39 ) 40 41 // Grow increases the length of s.P to lsiz. 42 func (s *LSym) Grow(lsiz int64) { 43 siz := int(lsiz) 44 if int64(siz) != lsiz { 45 log.Fatalf("LSym.Grow size %d too long", lsiz) 46 } 47 if len(s.P) >= siz { 48 return 49 } 50 s.P = append(s.P, make([]byte, siz-len(s.P))...) 51 } 52 53 // GrowCap increases the capacity of s.P to c. 54 func (s *LSym) GrowCap(c int64) { 55 if int64(cap(s.P)) >= c { 56 return 57 } 58 if s.P == nil { 59 s.P = make([]byte, 0, c) 60 return 61 } 62 b := make([]byte, len(s.P), c) 63 copy(b, s.P) 64 s.P = b 65 } 66 67 // prepwrite prepares to write data of size siz into s at offset off. 68 func (s *LSym) prepwrite(ctxt *Link, off int64, siz int) { 69 if off < 0 || siz < 0 || off >= 1<<30 { 70 ctxt.Diag("prepwrite: bad off=%d siz=%d s=%v", off, siz, s) 71 } 72 switch s.Type { 73 case objabi.Sxxx, objabi.SBSS: 74 s.Type = objabi.SDATA 75 case objabi.SNOPTRBSS: 76 s.Type = objabi.SNOPTRDATA 77 case objabi.STLSBSS: 78 ctxt.Diag("cannot supply data for %v var %v", s.Type, s.Name) 79 } 80 l := off + int64(siz) 81 s.Grow(l) 82 if l > s.Size { 83 s.Size = l 84 } 85 } 86 87 // WriteFloat32 writes f into s at offset off. 88 func (s *LSym) WriteFloat32(ctxt *Link, off int64, f float32) { 89 s.prepwrite(ctxt, off, 4) 90 ctxt.Arch.ByteOrder.PutUint32(s.P[off:], math.Float32bits(f)) 91 } 92 93 // WriteFloat64 writes f into s at offset off. 94 func (s *LSym) WriteFloat64(ctxt *Link, off int64, f float64) { 95 s.prepwrite(ctxt, off, 8) 96 ctxt.Arch.ByteOrder.PutUint64(s.P[off:], math.Float64bits(f)) 97 } 98 99 // WriteInt writes an integer i of size siz into s at offset off. 100 func (s *LSym) WriteInt(ctxt *Link, off int64, siz int, i int64) { 101 s.prepwrite(ctxt, off, siz) 102 switch siz { 103 default: 104 ctxt.Diag("WriteInt: bad integer size: %d", siz) 105 case 1: 106 s.P[off] = byte(i) 107 case 2: 108 ctxt.Arch.ByteOrder.PutUint16(s.P[off:], uint16(i)) 109 case 4: 110 ctxt.Arch.ByteOrder.PutUint32(s.P[off:], uint32(i)) 111 case 8: 112 ctxt.Arch.ByteOrder.PutUint64(s.P[off:], uint64(i)) 113 } 114 } 115 116 func (s *LSym) writeAddr(ctxt *Link, off int64, siz int, rsym *LSym, roff int64, rtype objabi.RelocType) { 117 // Allow 4-byte addresses for DWARF. 118 if siz != ctxt.Arch.PtrSize && siz != 4 { 119 ctxt.Diag("WriteAddr: bad address size %d in %s", siz, s.Name) 120 } 121 s.prepwrite(ctxt, off, siz) 122 r := Addrel(s) 123 r.Off = int32(off) 124 if int64(r.Off) != off { 125 ctxt.Diag("WriteAddr: off overflow %d in %s", off, s.Name) 126 } 127 r.Siz = uint8(siz) 128 r.Sym = rsym 129 r.Type = rtype 130 r.Add = roff 131 } 132 133 // WriteAddr writes an address of size siz into s at offset off. 134 // rsym and roff specify the relocation for the address. 135 func (s *LSym) WriteAddr(ctxt *Link, off int64, siz int, rsym *LSym, roff int64) { 136 s.writeAddr(ctxt, off, siz, rsym, roff, objabi.R_ADDR) 137 } 138 139 // WriteWeakAddr writes an address of size siz into s at offset off. 140 // rsym and roff specify the relocation for the address. 141 // This is a weak reference. 142 func (s *LSym) WriteWeakAddr(ctxt *Link, off int64, siz int, rsym *LSym, roff int64) { 143 s.writeAddr(ctxt, off, siz, rsym, roff, objabi.R_WEAKADDR) 144 } 145 146 // WriteCURelativeAddr writes a pointer-sized address into s at offset off. 147 // rsym and roff specify the relocation for the address which will be 148 // resolved by the linker to an offset from the DW_AT_low_pc attribute of 149 // the DWARF Compile Unit of rsym. 150 func (s *LSym) WriteCURelativeAddr(ctxt *Link, off int64, rsym *LSym, roff int64) { 151 s.writeAddr(ctxt, off, ctxt.Arch.PtrSize, rsym, roff, objabi.R_ADDRCUOFF) 152 } 153 154 // WriteOff writes a 4 byte offset to rsym+roff into s at offset off. 155 // After linking the 4 bytes stored at s+off will be 156 // rsym+roff-(start of section that s is in). 157 func (s *LSym) WriteOff(ctxt *Link, off int64, rsym *LSym, roff int64) { 158 s.prepwrite(ctxt, off, 4) 159 r := Addrel(s) 160 r.Off = int32(off) 161 if int64(r.Off) != off { 162 ctxt.Diag("WriteOff: off overflow %d in %s", off, s.Name) 163 } 164 r.Siz = 4 165 r.Sym = rsym 166 r.Type = objabi.R_ADDROFF 167 r.Add = roff 168 } 169 170 // WriteWeakOff writes a weak 4 byte offset to rsym+roff into s at offset off. 171 // After linking the 4 bytes stored at s+off will be 172 // rsym+roff-(start of section that s is in). 173 func (s *LSym) WriteWeakOff(ctxt *Link, off int64, rsym *LSym, roff int64) { 174 s.prepwrite(ctxt, off, 4) 175 r := Addrel(s) 176 r.Off = int32(off) 177 if int64(r.Off) != off { 178 ctxt.Diag("WriteOff: off overflow %d in %s", off, s.Name) 179 } 180 r.Siz = 4 181 r.Sym = rsym 182 r.Type = objabi.R_WEAKADDROFF 183 r.Add = roff 184 } 185 186 // WriteString writes a string of size siz into s at offset off. 187 func (s *LSym) WriteString(ctxt *Link, off int64, siz int, str string) { 188 if siz < len(str) { 189 ctxt.Diag("WriteString: bad string size: %d < %d", siz, len(str)) 190 } 191 s.prepwrite(ctxt, off, siz) 192 copy(s.P[off:off+int64(siz)], str) 193 } 194 195 // WriteBytes writes a slice of bytes into s at offset off. 196 func (s *LSym) WriteBytes(ctxt *Link, off int64, b []byte) int64 { 197 s.prepwrite(ctxt, off, len(b)) 198 copy(s.P[off:], b) 199 return off + int64(len(b)) 200 } 201 202 func Addrel(s *LSym) *Reloc { 203 if s.R == nil { 204 s.R = make([]Reloc, 0, 4) 205 } 206 s.R = append(s.R, Reloc{}) 207 return &s.R[len(s.R)-1] 208 }