1// Inferno utils/6l/obj.c 2// https://bitbucket.org/inferno-os/inferno-os/src/master/utils/6l/obj.c 3// 4// Copyright © 1994-1999 Lucent Technologies Inc. All rights reserved. 5// Portions Copyright © 1995-1997 C H Forsyth (forsyth@terzarima.net) 6// Portions Copyright © 1997-1999 Vita Nuova Limited 7// Portions Copyright © 2000-2007 Vita Nuova Holdings Limited (www.vitanuova.com) 8// Portions Copyright © 2004,2006 Bruce Ellis 9// Portions Copyright © 2005-2007 C H Forsyth (forsyth@terzarima.net) 10// Revisions Copyright © 2000-2007 Lucent Technologies Inc. and others 11// Portions Copyright © 2009 The Go Authors. All rights reserved. 12// 13// Permission is hereby granted, free of charge, to any person obtaining a copy 14// of this software and associated documentation files (the "Software"), to deal 15// in the Software without restriction, including without limitation the rights 16// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell 17// copies of the Software, and to permit persons to whom the Software is 18// furnished to do so, subject to the following conditions: 19// 20// The above copyright notice and this permission notice shall be included in 21// all copies or substantial portions of the Software. 22// 23// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 24// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 25// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 26// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 27// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 28// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN 29// THE SOFTWARE. 30 31package ld 32 33import ( 34 "bufio" 35 "cmd/internal/goobj" 36 "cmd/internal/objabi" 37 "cmd/internal/quoted" 38 "cmd/internal/sys" 39 "cmd/link/internal/benchmark" 40 "flag" 41 "internal/buildcfg" 42 "log" 43 "os" 44 "runtime" 45 "runtime/pprof" 46 "strings" 47) 48 49var ( 50 pkglistfornote []byte 51 windowsgui bool // writes a "GUI binary" instead of a "console binary" 52 ownTmpDir bool // set to true if tmp dir created by linker (e.g. no -tmpdir) 53) 54 55func init() { 56 flag.Var(&rpath, "r", "set the ELF dynamic linker search `path` to dir1:dir2:...") 57 flag.Var(&flagExtld, "extld", "use `linker` when linking in external mode") 58 flag.Var(&flagExtldflags, "extldflags", "pass `flags` to external linker") 59} 60 61// Flags used by the linker. The exported flags are used by the architecture-specific packages. 62var ( 63 flagBuildid = flag.String("buildid", "", "record `id` as Go toolchain build id") 64 65 flagOutfile = flag.String("o", "", "write output to `file`") 66 flagPluginPath = flag.String("pluginpath", "", "full path name for plugin") 67 68 flagInstallSuffix = flag.String("installsuffix", "", "set package directory `suffix`") 69 flagDumpDep = flag.Bool("dumpdep", false, "dump symbol dependency graph") 70 flagRace = flag.Bool("race", false, "enable race detector") 71 flagMsan = flag.Bool("msan", false, "enable MSan interface") 72 flagAsan = flag.Bool("asan", false, "enable ASan interface") 73 flagAslr = flag.Bool("aslr", true, "enable ASLR for buildmode=c-shared on windows") 74 75 flagFieldTrack = flag.String("k", "", "set field tracking `symbol`") 76 flagLibGCC = flag.String("libgcc", "", "compiler support lib for internal linking; use \"none\" to disable") 77 flagTmpdir = flag.String("tmpdir", "", "use `directory` for temporary files") 78 79 flagExtld quoted.Flag 80 flagExtldflags quoted.Flag 81 flagExtar = flag.String("extar", "", "archive program for buildmode=c-archive") 82 83 flagA = flag.Bool("a", false, "no-op (deprecated)") 84 FlagC = flag.Bool("c", false, "dump call graph") 85 FlagD = flag.Bool("d", false, "disable dynamic executable") 86 flagF = flag.Bool("f", false, "ignore version mismatch") 87 flagG = flag.Bool("g", false, "disable go package data checks") 88 flagH = flag.Bool("h", false, "halt on error") 89 flagN = flag.Bool("n", false, "dump symbol table") 90 FlagS = flag.Bool("s", false, "disable symbol table") 91 FlagW = flag.Bool("w", false, "disable DWARF generation") 92 flag8 bool // use 64-bit addresses in symbol table 93 flagInterpreter = flag.String("I", "", "use `linker` as ELF dynamic linker") 94 FlagDebugTramp = flag.Int("debugtramp", 0, "debug trampolines") 95 FlagDebugTextSize = flag.Int("debugtextsize", 0, "debug text section max size") 96 FlagStrictDups = flag.Int("strictdups", 0, "sanity check duplicate symbol contents during object file reading (1=warn 2=err).") 97 FlagRound = flag.Int("R", -1, "set address rounding `quantum`") 98 FlagTextAddr = flag.Int64("T", -1, "set text segment `address`") 99 flagEntrySymbol = flag.String("E", "", "set `entry` symbol name") 100 cpuprofile = flag.String("cpuprofile", "", "write cpu profile to `file`") 101 memprofile = flag.String("memprofile", "", "write memory profile to `file`") 102 memprofilerate = flag.Int64("memprofilerate", 0, "set runtime.MemProfileRate to `rate`") 103 benchmarkFlag = flag.String("benchmark", "", "set to 'mem' or 'cpu' to enable phase benchmarking") 104 benchmarkFileFlag = flag.String("benchmarkprofile", "", "emit phase profiles to `base`_phase.{cpu,mem}prof") 105) 106 107// Main is the main entry point for the linker code. 108func Main(arch *sys.Arch, theArch Arch) { 109 thearch = theArch 110 ctxt := linknew(arch) 111 ctxt.Bso = bufio.NewWriter(os.Stdout) 112 113 // For testing behavior of go command when tools crash silently. 114 // Undocumented, not in standard flag parser to avoid 115 // exposing in usage message. 116 for _, arg := range os.Args { 117 if arg == "-crash_for_testing" { 118 os.Exit(2) 119 } 120 } 121 122 final := gorootFinal() 123 addstrdata1(ctxt, "runtime.defaultGOROOT="+final) 124 addstrdata1(ctxt, "internal/buildcfg.defaultGOROOT="+final) 125 126 buildVersion := buildcfg.Version 127 if goexperiment := buildcfg.GOEXPERIMENT(); goexperiment != "" { 128 buildVersion += " X:" + goexperiment 129 } 130 addstrdata1(ctxt, "runtime.buildVersion="+buildVersion) 131 132 // TODO(matloob): define these above and then check flag values here 133 if ctxt.Arch.Family == sys.AMD64 && buildcfg.GOOS == "plan9" { 134 flag.BoolVar(&flag8, "8", false, "use 64-bit addresses in symbol table") 135 } 136 flagHeadType := flag.String("H", "", "set header `type`") 137 flag.BoolVar(&ctxt.linkShared, "linkshared", false, "link against installed Go shared libraries") 138 flag.Var(&ctxt.LinkMode, "linkmode", "set link `mode`") 139 flag.Var(&ctxt.BuildMode, "buildmode", "set build `mode`") 140 flag.BoolVar(&ctxt.compressDWARF, "compressdwarf", true, "compress DWARF if possible") 141 objabi.Flagfn1("B", "add an ELF NT_GNU_BUILD_ID `note` when using ELF", addbuildinfo) 142 objabi.Flagfn1("L", "add specified `directory` to library path", func(a string) { Lflag(ctxt, a) }) 143 objabi.AddVersionFlag() // -V 144 objabi.Flagfn1("X", "add string value `definition` of the form importpath.name=value", func(s string) { addstrdata1(ctxt, s) }) 145 objabi.Flagcount("v", "print link trace", &ctxt.Debugvlog) 146 objabi.Flagfn1("importcfg", "read import configuration from `file`", ctxt.readImportCfg) 147 148 objabi.Flagparse(usage) 149 150 if ctxt.Debugvlog > 0 { 151 // dump symbol info on crash 152 defer func() { ctxt.loader.Dump() }() 153 } 154 155 switch *flagHeadType { 156 case "": 157 case "windowsgui": 158 ctxt.HeadType = objabi.Hwindows 159 windowsgui = true 160 default: 161 if err := ctxt.HeadType.Set(*flagHeadType); err != nil { 162 Errorf(nil, "%v", err) 163 usage() 164 } 165 } 166 if ctxt.HeadType == objabi.Hunknown { 167 ctxt.HeadType.Set(buildcfg.GOOS) 168 } 169 170 if !*flagAslr && ctxt.BuildMode != BuildModeCShared { 171 Errorf(nil, "-aslr=false is only allowed for -buildmode=c-shared") 172 usage() 173 } 174 175 if *FlagD && ctxt.UsesLibc() { 176 Exitf("dynamic linking required on %s; -d flag cannot be used", buildcfg.GOOS) 177 } 178 179 checkStrictDups = *FlagStrictDups 180 181 if !buildcfg.Experiment.RegabiWrappers { 182 abiInternalVer = 0 183 } 184 185 startProfile() 186 if ctxt.BuildMode == BuildModeUnset { 187 ctxt.BuildMode.Set("exe") 188 } 189 190 if ctxt.BuildMode != BuildModeShared && flag.NArg() != 1 { 191 usage() 192 } 193 194 if *flagOutfile == "" { 195 *flagOutfile = "a.out" 196 if ctxt.HeadType == objabi.Hwindows { 197 *flagOutfile += ".exe" 198 } 199 } 200 201 interpreter = *flagInterpreter 202 203 if *flagBuildid == "" && ctxt.Target.IsOpenbsd() { 204 // TODO(jsing): Remove once direct syscalls are no longer in use. 205 // OpenBSD 6.7 onwards will not permit direct syscalls from a 206 // dynamically linked binary unless it identifies the binary 207 // contains a .note.go.buildid ELF note. See issue #36435. 208 *flagBuildid = "go-openbsd" 209 } 210 211 // enable benchmarking 212 var bench *benchmark.Metrics 213 if len(*benchmarkFlag) != 0 { 214 if *benchmarkFlag == "mem" { 215 bench = benchmark.New(benchmark.GC, *benchmarkFileFlag) 216 } else if *benchmarkFlag == "cpu" { 217 bench = benchmark.New(benchmark.NoGC, *benchmarkFileFlag) 218 } else { 219 Errorf(nil, "unknown benchmark flag: %q", *benchmarkFlag) 220 usage() 221 } 222 } 223 224 bench.Start("libinit") 225 libinit(ctxt) // creates outfile 226 bench.Start("computeTLSOffset") 227 ctxt.computeTLSOffset() 228 bench.Start("Archinit") 229 thearch.Archinit(ctxt) 230 231 if ctxt.linkShared && !ctxt.IsELF { 232 Exitf("-linkshared can only be used on elf systems") 233 } 234 235 if ctxt.Debugvlog != 0 { 236 ctxt.Logf("HEADER = -H%d -T0x%x -R0x%x\n", ctxt.HeadType, uint64(*FlagTextAddr), uint32(*FlagRound)) 237 } 238 239 zerofp := goobj.FingerprintType{} 240 switch ctxt.BuildMode { 241 case BuildModeShared: 242 for i := 0; i < flag.NArg(); i++ { 243 arg := flag.Arg(i) 244 parts := strings.SplitN(arg, "=", 2) 245 var pkgpath, file string 246 if len(parts) == 1 { 247 pkgpath, file = "main", arg 248 } else { 249 pkgpath, file = parts[0], parts[1] 250 } 251 pkglistfornote = append(pkglistfornote, pkgpath...) 252 pkglistfornote = append(pkglistfornote, '\n') 253 addlibpath(ctxt, "command line", "command line", file, pkgpath, "", zerofp) 254 } 255 case BuildModePlugin: 256 addlibpath(ctxt, "command line", "command line", flag.Arg(0), *flagPluginPath, "", zerofp) 257 default: 258 addlibpath(ctxt, "command line", "command line", flag.Arg(0), "main", "", zerofp) 259 } 260 bench.Start("loadlib") 261 ctxt.loadlib() 262 263 bench.Start("deadcode") 264 deadcode(ctxt) 265 266 bench.Start("linksetup") 267 ctxt.linksetup() 268 269 bench.Start("dostrdata") 270 ctxt.dostrdata() 271 if buildcfg.Experiment.FieldTrack { 272 bench.Start("fieldtrack") 273 fieldtrack(ctxt.Arch, ctxt.loader) 274 } 275 276 bench.Start("dwarfGenerateDebugInfo") 277 dwarfGenerateDebugInfo(ctxt) 278 279 bench.Start("callgraph") 280 ctxt.callgraph() 281 282 bench.Start("dostkcheck") 283 ctxt.dostkcheck() 284 285 bench.Start("mangleTypeSym") 286 ctxt.mangleTypeSym() 287 288 if ctxt.IsELF { 289 bench.Start("doelf") 290 ctxt.doelf() 291 } 292 if ctxt.IsDarwin() { 293 bench.Start("domacho") 294 ctxt.domacho() 295 } 296 if ctxt.IsWindows() { 297 bench.Start("dope") 298 ctxt.dope() 299 bench.Start("windynrelocsyms") 300 ctxt.windynrelocsyms() 301 } 302 if ctxt.IsAIX() { 303 bench.Start("doxcoff") 304 ctxt.doxcoff() 305 } 306 307 bench.Start("textbuildid") 308 ctxt.textbuildid() 309 bench.Start("addexport") 310 ctxt.setArchSyms() 311 ctxt.addexport() 312 bench.Start("Gentext") 313 thearch.Gentext(ctxt, ctxt.loader) // trampolines, call stubs, etc. 314 315 bench.Start("textaddress") 316 ctxt.textaddress() 317 bench.Start("typelink") 318 ctxt.typelink() 319 bench.Start("buildinfo") 320 ctxt.buildinfo() 321 bench.Start("pclntab") 322 containers := ctxt.findContainerSyms() 323 pclnState := ctxt.pclntab(containers) 324 bench.Start("findfunctab") 325 ctxt.findfunctab(pclnState, containers) 326 bench.Start("dwarfGenerateDebugSyms") 327 dwarfGenerateDebugSyms(ctxt) 328 bench.Start("symtab") 329 symGroupType := ctxt.symtab(pclnState) 330 bench.Start("dodata") 331 ctxt.dodata(symGroupType) 332 bench.Start("address") 333 order := ctxt.address() 334 bench.Start("dwarfcompress") 335 dwarfcompress(ctxt) 336 bench.Start("layout") 337 filesize := ctxt.layout(order) 338 339 // Write out the output file. 340 // It is split into two parts (Asmb and Asmb2). The first 341 // part writes most of the content (sections and segments), 342 // for which we have computed the size and offset, in a 343 // mmap'd region. The second part writes more content, for 344 // which we don't know the size. 345 if ctxt.Arch.Family != sys.Wasm { 346 // Don't mmap if we're building for Wasm. Wasm file 347 // layout is very different so filesize is meaningless. 348 if err := ctxt.Out.Mmap(filesize); err != nil { 349 Exitf("mapping output file failed: %v", err) 350 } 351 } 352 // asmb will redirect symbols to the output file mmap, and relocations 353 // will be applied directly there. 354 bench.Start("Asmb") 355 asmb(ctxt) 356 357 exitIfErrors() 358 359 // Generate additional symbols for the native symbol table just prior 360 // to code generation. 361 bench.Start("GenSymsLate") 362 if thearch.GenSymsLate != nil { 363 thearch.GenSymsLate(ctxt, ctxt.loader) 364 } 365 366 bench.Start("Asmb2") 367 asmb2(ctxt) 368 369 bench.Start("Munmap") 370 ctxt.Out.Close() // Close handles Munmapping if necessary. 371 372 bench.Start("hostlink") 373 ctxt.hostlink() 374 if ctxt.Debugvlog != 0 { 375 ctxt.Logf("%s", ctxt.loader.Stat()) 376 ctxt.Logf("%d liveness data\n", liveness) 377 } 378 bench.Start("Flush") 379 ctxt.Bso.Flush() 380 bench.Start("archive") 381 ctxt.archive() 382 bench.Report(os.Stdout) 383 384 errorexit() 385} 386 387type Rpath struct { 388 set bool 389 val string 390} 391 392func (r *Rpath) Set(val string) error { 393 r.set = true 394 r.val = val 395 return nil 396} 397 398func (r *Rpath) String() string { 399 return r.val 400} 401 402func startProfile() { 403 if *cpuprofile != "" { 404 f, err := os.Create(*cpuprofile) 405 if err != nil { 406 log.Fatalf("%v", err) 407 } 408 if err := pprof.StartCPUProfile(f); err != nil { 409 log.Fatalf("%v", err) 410 } 411 AtExit(pprof.StopCPUProfile) 412 } 413 if *memprofile != "" { 414 if *memprofilerate != 0 { 415 runtime.MemProfileRate = int(*memprofilerate) 416 } 417 f, err := os.Create(*memprofile) 418 if err != nil { 419 log.Fatalf("%v", err) 420 } 421 AtExit(func() { 422 // Profile all outstanding allocations. 423 runtime.GC() 424 // compilebench parses the memory profile to extract memstats, 425 // which are only written in the legacy pprof format. 426 // See golang.org/issue/18641 and runtime/pprof/pprof.go:writeHeap. 427 const writeLegacyFormat = 1 428 if err := pprof.Lookup("heap").WriteTo(f, writeLegacyFormat); err != nil { 429 log.Fatalf("%v", err) 430 } 431 }) 432 } 433} 434