src/cmd/link/internal/loadpe/ldpe.go

   1 // Copyright 2010 The Go Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style
   3 // license that can be found in the LICENSE file.
   4
   5 // Package loadpe implements a PE/COFF file reader.
   6 package loadpe
   7
   8 import (
   9         "bytes"
  10         "cmd/internal/bio"
  11         "cmd/internal/objabi"
  12         "cmd/internal/sys"
  13         "cmd/link/internal/loader"
  14         "cmd/link/internal/sym"
  15         "debug/pe"
  16         "encoding/binary"
  17         "errors"
  18         "fmt"
  19         "io"
  20         "strings"
  21 )
  22
  23 const (
  24         // TODO: the Microsoft doco says IMAGE_SYM_DTYPE_ARRAY is 3 (same with IMAGE_SYM_DTYPE_POINTER and IMAGE_SYM_DTYPE_FUNCTION)
  25         IMAGE_SYM_UNDEFINED              = 0
  26         IMAGE_SYM_ABSOLUTE               = -1
  27         IMAGE_SYM_DEBUG                  = -2
  28         IMAGE_SYM_TYPE_NULL              = 0
  29         IMAGE_SYM_TYPE_VOID              = 1
  30         IMAGE_SYM_TYPE_CHAR              = 2
  31         IMAGE_SYM_TYPE_SHORT             = 3
  32         IMAGE_SYM_TYPE_INT               = 4
  33         IMAGE_SYM_TYPE_LONG              = 5
  34         IMAGE_SYM_TYPE_FLOAT             = 6
  35         IMAGE_SYM_TYPE_DOUBLE            = 7
  36         IMAGE_SYM_TYPE_STRUCT            = 8
  37         IMAGE_SYM_TYPE_UNION             = 9
  38         IMAGE_SYM_TYPE_ENUM              = 10
  39         IMAGE_SYM_TYPE_MOE               = 11
  40         IMAGE_SYM_TYPE_BYTE              = 12
  41         IMAGE_SYM_TYPE_WORD              = 13
  42         IMAGE_SYM_TYPE_UINT              = 14
  43         IMAGE_SYM_TYPE_DWORD             = 15
  44         IMAGE_SYM_TYPE_PCODE             = 32768
  45         IMAGE_SYM_DTYPE_NULL             = 0
  46         IMAGE_SYM_DTYPE_POINTER          = 0x10
  47         IMAGE_SYM_DTYPE_FUNCTION         = 0x20
  48         IMAGE_SYM_DTYPE_ARRAY            = 0x30
  49         IMAGE_SYM_CLASS_END_OF_FUNCTION  = -1
  50         IMAGE_SYM_CLASS_NULL             = 0
  51         IMAGE_SYM_CLASS_AUTOMATIC        = 1
  52         IMAGE_SYM_CLASS_EXTERNAL         = 2
  53         IMAGE_SYM_CLASS_STATIC           = 3
  54         IMAGE_SYM_CLASS_REGISTER         = 4
  55         IMAGE_SYM_CLASS_EXTERNAL_DEF     = 5
  56         IMAGE_SYM_CLASS_LABEL            = 6
  57         IMAGE_SYM_CLASS_UNDEFINED_LABEL  = 7
  58         IMAGE_SYM_CLASS_MEMBER_OF_STRUCT = 8
  59         IMAGE_SYM_CLASS_ARGUMENT         = 9
  60         IMAGE_SYM_CLASS_STRUCT_TAG       = 10
  61         IMAGE_SYM_CLASS_MEMBER_OF_UNION  = 11
  62         IMAGE_SYM_CLASS_UNION_TAG        = 12
  63         IMAGE_SYM_CLASS_TYPE_DEFINITION  = 13
  64         IMAGE_SYM_CLASS_UNDEFINED_STATIC = 14
  65         IMAGE_SYM_CLASS_ENUM_TAG         = 15
  66         IMAGE_SYM_CLASS_MEMBER_OF_ENUM   = 16
  67         IMAGE_SYM_CLASS_REGISTER_PARAM   = 17
  68         IMAGE_SYM_CLASS_BIT_FIELD        = 18
  69         IMAGE_SYM_CLASS_FAR_EXTERNAL     = 68 /* Not in PECOFF v8 spec */
  70         IMAGE_SYM_CLASS_BLOCK            = 100
  71         IMAGE_SYM_CLASS_FUNCTION         = 101
  72         IMAGE_SYM_CLASS_END_OF_STRUCT    = 102
  73         IMAGE_SYM_CLASS_FILE             = 103
  74         IMAGE_SYM_CLASS_SECTION          = 104
  75         IMAGE_SYM_CLASS_WEAK_EXTERNAL    = 105
  76         IMAGE_SYM_CLASS_CLR_TOKEN        = 107
  77         IMAGE_REL_I386_ABSOLUTE          = 0x0000
  78         IMAGE_REL_I386_DIR16             = 0x0001
  79         IMAGE_REL_I386_REL16             = 0x0002
  80         IMAGE_REL_I386_DIR32             = 0x0006
  81         IMAGE_REL_I386_DIR32NB           = 0x0007
  82         IMAGE_REL_I386_SEG12             = 0x0009
  83         IMAGE_REL_I386_SECTION           = 0x000A
  84         IMAGE_REL_I386_SECREL            = 0x000B
  85         IMAGE_REL_I386_TOKEN             = 0x000C
  86         IMAGE_REL_I386_SECREL7           = 0x000D
  87         IMAGE_REL_I386_REL32             = 0x0014
  88         IMAGE_REL_AMD64_ABSOLUTE         = 0x0000
  89         IMAGE_REL_AMD64_ADDR64           = 0x0001
  90         IMAGE_REL_AMD64_ADDR32           = 0x0002
  91         IMAGE_REL_AMD64_ADDR32NB         = 0x0003
  92         IMAGE_REL_AMD64_REL32            = 0x0004
  93         IMAGE_REL_AMD64_REL32_1          = 0x0005
  94         IMAGE_REL_AMD64_REL32_2          = 0x0006
  95         IMAGE_REL_AMD64_REL32_3          = 0x0007
  96         IMAGE_REL_AMD64_REL32_4          = 0x0008
  97         IMAGE_REL_AMD64_REL32_5          = 0x0009
  98         IMAGE_REL_AMD64_SECTION          = 0x000A
  99         IMAGE_REL_AMD64_SECREL           = 0x000B
 100         IMAGE_REL_AMD64_SECREL7          = 0x000C
 101         IMAGE_REL_AMD64_TOKEN            = 0x000D
 102         IMAGE_REL_AMD64_SREL32           = 0x000E
 103         IMAGE_REL_AMD64_PAIR             = 0x000F
 104         IMAGE_REL_AMD64_SSPAN32          = 0x0010
 105         IMAGE_REL_ARM_ABSOLUTE           = 0x0000
 106         IMAGE_REL_ARM_ADDR32             = 0x0001
 107         IMAGE_REL_ARM_ADDR32NB           = 0x0002
 108         IMAGE_REL_ARM_BRANCH24           = 0x0003
 109         IMAGE_REL_ARM_BRANCH11           = 0x0004
 110         IMAGE_REL_ARM_SECTION            = 0x000E
 111         IMAGE_REL_ARM_SECREL             = 0x000F
 112         IMAGE_REL_ARM_MOV32              = 0x0010
 113         IMAGE_REL_THUMB_MOV32            = 0x0011
 114         IMAGE_REL_THUMB_BRANCH20         = 0x0012
 115         IMAGE_REL_THUMB_BRANCH24         = 0x0014
 116         IMAGE_REL_THUMB_BLX23            = 0x0015
 117         IMAGE_REL_ARM_PAIR               = 0x0016
 118         IMAGE_REL_ARM64_ABSOLUTE         = 0x0000
 119         IMAGE_REL_ARM64_ADDR32           = 0x0001
 120         IMAGE_REL_ARM64_ADDR32NB         = 0x0002
 121         IMAGE_REL_ARM64_BRANCH26         = 0x0003
 122         IMAGE_REL_ARM64_PAGEBASE_REL21   = 0x0004
 123         IMAGE_REL_ARM64_REL21            = 0x0005
 124         IMAGE_REL_ARM64_PAGEOFFSET_12A   = 0x0006
 125         IMAGE_REL_ARM64_PAGEOFFSET_12L   = 0x0007
 126         IMAGE_REL_ARM64_SECREL           = 0x0008
 127         IMAGE_REL_ARM64_SECREL_LOW12A    = 0x0009
 128         IMAGE_REL_ARM64_SECREL_HIGH12A   = 0x000A
 129         IMAGE_REL_ARM64_SECREL_LOW12L    = 0x000B
 130         IMAGE_REL_ARM64_TOKEN            = 0x000C
 131         IMAGE_REL_ARM64_SECTION          = 0x000D
 132         IMAGE_REL_ARM64_ADDR64           = 0x000E
 133         IMAGE_REL_ARM64_BRANCH19         = 0x000F
 134         IMAGE_REL_ARM64_BRANCH14         = 0x0010
 135         IMAGE_REL_ARM64_REL32            = 0x0011
 136 )
 137
 138 // TODO(crawshaw): de-duplicate these symbols with cmd/internal/ld, ideally in debug/pe.
 139 const (
 140         IMAGE_SCN_CNT_CODE               = 0x00000020
 141         IMAGE_SCN_CNT_INITIALIZED_DATA   = 0x00000040
 142         IMAGE_SCN_CNT_UNINITIALIZED_DATA = 0x00000080
 143         IMAGE_SCN_MEM_DISCARDABLE        = 0x02000000
 144         IMAGE_SCN_MEM_EXECUTE            = 0x20000000
 145         IMAGE_SCN_MEM_READ               = 0x40000000
 146         IMAGE_SCN_MEM_WRITE              = 0x80000000
 147 )
 148
 149 // TODO(brainman): maybe just add ReadAt method to bio.Reader instead of creating peBiobuf
 150
 151 // peBiobuf makes bio.Reader look like io.ReaderAt.
 152 type peBiobuf bio.Reader
 153
 154 func (f *peBiobuf) ReadAt(p []byte, off int64) (int, error) {
 155         ret := ((*bio.Reader)(f)).MustSeek(off, 0)
 156         if ret < 0 {
 157                 return 0, errors.New("fail to seek")
 158         }
 159         n, err := f.Read(p)
 160         if err != nil {
 161                 return 0, err
 162         }
 163         return n, nil
 164 }
 165
 166 // makeUpdater creates a loader.SymbolBuilder if one hasn't been created previously.
 167 // We use this to lazily make SymbolBuilders as we don't always need a builder, and creating them for all symbols might be an error.
 168 func makeUpdater(l *loader.Loader, bld *loader.SymbolBuilder, s loader.Sym) *loader.SymbolBuilder {
 169         if bld != nil {
 170                 return bld
 171         }
 172         bld = l.MakeSymbolUpdater(s)
 173         return bld
 174 }
 175
 176 // Load loads the PE file pn from input.
 177 // Symbols are written into syms, and a slice of the text symbols is returned.
 178 // If an .rsrc section or set of .rsrc$xx sections is found, its symbols are
 179 // returned as rsrc.
 180 func Load(l *loader.Loader, arch *sys.Arch, localSymVersion int, input *bio.Reader, pkg string, length int64, pn string) (textp []loader.Sym, rsrc []loader.Sym, err error) {
 181         lookup := l.LookupOrCreateCgoExport
 182         sectsyms := make(map[*pe.Section]loader.Sym)
 183         sectdata := make(map[*pe.Section][]byte)
 184
 185         // Some input files are archives containing multiple of
 186         // object files, and pe.NewFile seeks to the start of
 187         // input file and get confused. Create section reader
 188         // to stop pe.NewFile looking before current position.
 189         sr := io.NewSectionReader((*peBiobuf)(input), input.Offset(), 1<<63-1)
 190
 191         // TODO: replace pe.NewFile with pe.Load (grep for "add Load function" in debug/pe for details)
 192         f, err := pe.NewFile(sr)
 193         if err != nil {
 194                 return nil, nil, err
 195         }
 196         defer f.Close()
 197
 198         // TODO return error if found .cormeta
 199
 200         // create symbols for mapped sections
 201         for _, sect := range f.Sections {
 202                 if sect.Characteristics&IMAGE_SCN_MEM_DISCARDABLE != 0 {
 203                         continue
 204                 }
 205
 206                 if sect.Characteristics&(IMAGE_SCN_CNT_CODE|IMAGE_SCN_CNT_INITIALIZED_DATA|IMAGE_SCN_CNT_UNINITIALIZED_DATA) == 0 {
 207                         // This has been seen for .idata sections, which we
 208                         // want to ignore. See issues 5106 and 5273.
 209                         continue
 210                 }
 211
 212                 name := fmt.Sprintf("%s(%s)", pkg, sect.Name)
 213                 s := lookup(name, localSymVersion)
 214                 bld := l.MakeSymbolUpdater(s)
 215
 216                 switch sect.Characteristics & (IMAGE_SCN_CNT_UNINITIALIZED_DATA | IMAGE_SCN_CNT_INITIALIZED_DATA | IMAGE_SCN_MEM_READ | IMAGE_SCN_MEM_WRITE | IMAGE_SCN_CNT_CODE | IMAGE_SCN_MEM_EXECUTE) {
 217                 case IMAGE_SCN_CNT_INITIALIZED_DATA | IMAGE_SCN_MEM_READ: //.rdata
 218                         bld.SetType(sym.SRODATA)
 219
 220                 case IMAGE_SCN_CNT_UNINITIALIZED_DATA | IMAGE_SCN_MEM_READ | IMAGE_SCN_MEM_WRITE: //.bss
 221                         bld.SetType(sym.SNOPTRBSS)
 222
 223                 case IMAGE_SCN_CNT_INITIALIZED_DATA | IMAGE_SCN_MEM_READ | IMAGE_SCN_MEM_WRITE: //.data
 224                         bld.SetType(sym.SNOPTRDATA)
 225
 226                 case IMAGE_SCN_CNT_CODE | IMAGE_SCN_MEM_EXECUTE | IMAGE_SCN_MEM_READ: //.text
 227                         bld.SetType(sym.STEXT)
 228
 229                 default:
 230                         return nil, nil, fmt.Errorf("unexpected flags %#06x for PE section %s", sect.Characteristics, sect.Name)
 231                 }
 232
 233                 if bld.Type() != sym.SNOPTRBSS {
 234                         data, err := sect.Data()
 235                         if err != nil {
 236                                 return nil, nil, err
 237                         }
 238                         sectdata[sect] = data
 239                         bld.SetData(data)
 240                 }
 241                 bld.SetSize(int64(sect.Size))
 242                 sectsyms[sect] = s
 243                 if sect.Name == ".rsrc" || strings.HasPrefix(sect.Name, ".rsrc$") {
 244                         rsrc = append(rsrc, s)
 245                 }
 246         }
 247
 248         // load relocations
 249         for _, rsect := range f.Sections {
 250                 if _, found := sectsyms[rsect]; !found {
 251                         continue
 252                 }
 253                 if rsect.NumberOfRelocations == 0 {
 254                         continue
 255                 }
 256                 if rsect.Characteristics&IMAGE_SCN_MEM_DISCARDABLE != 0 {
 257                         continue
 258                 }
 259                 if rsect.Characteristics&(IMAGE_SCN_CNT_CODE|IMAGE_SCN_CNT_INITIALIZED_DATA|IMAGE_SCN_CNT_UNINITIALIZED_DATA) == 0 {
 260                         // This has been seen for .idata sections, which we
 261                         // want to ignore. See issues 5106 and 5273.
 262                         continue
 263                 }
 264
 265                 splitResources := strings.HasPrefix(rsect.Name, ".rsrc$")
 266                 sb := l.MakeSymbolUpdater(sectsyms[rsect])
 267                 for j, r := range rsect.Relocs {
 268                         if int(r.SymbolTableIndex) >= len(f.COFFSymbols) {
 269                                 return nil, nil, fmt.Errorf("relocation number %d symbol index idx=%d cannot be large then number of symbols %d", j, r.SymbolTableIndex, len(f.COFFSymbols))
 270                         }
 271                         pesym := &f.COFFSymbols[r.SymbolTableIndex]
 272                         _, gosym, err := readpesym(l, arch, lookup, f, pesym, sectsyms, localSymVersion)
 273                         if err != nil {
 274                                 return nil, nil, err
 275                         }
 276                         if gosym == 0 {
 277                                 name, err := pesym.FullName(f.StringTable)
 278                                 if err != nil {
 279                                         name = string(pesym.Name[:])
 280                                 }
 281                                 return nil, nil, fmt.Errorf("reloc of invalid sym %s idx=%d type=%d", name, r.SymbolTableIndex, pesym.Type)
 282                         }
 283
 284                         rSym := gosym
 285                         rSize := uint8(4)
 286                         rOff := int32(r.VirtualAddress)
 287                         var rAdd int64
 288                         var rType objabi.RelocType
 289                         switch arch.Family {
 290                         default:
 291                                 return nil, nil, fmt.Errorf("%s: unsupported arch %v", pn, arch.Family)
 292                         case sys.I386, sys.AMD64:
 293                                 switch r.Type {
 294                                 default:
 295                                         return nil, nil, fmt.Errorf("%s: %v: unknown relocation type %v", pn, sectsyms[rsect], r.Type)
 296
 297                                 case IMAGE_REL_I386_REL32, IMAGE_REL_AMD64_REL32,
 298                                         IMAGE_REL_AMD64_ADDR32, // R_X86_64_PC32
 299                                         IMAGE_REL_AMD64_ADDR32NB:
 300                                         rType = objabi.R_PCREL
 301
 302                                         rAdd = int64(int32(binary.LittleEndian.Uint32(sectdata[rsect][rOff:])))
 303
 304                                 case IMAGE_REL_I386_DIR32NB, IMAGE_REL_I386_DIR32:
 305                                         rType = objabi.R_ADDR
 306
 307                                         // load addend from image
 308                                         rAdd = int64(int32(binary.LittleEndian.Uint32(sectdata[rsect][rOff:])))
 309
 310                                 case IMAGE_REL_AMD64_ADDR64: // R_X86_64_64
 311                                         rSize = 8
 312
 313                                         rType = objabi.R_ADDR
 314
 315                                         // load addend from image
 316                                         rAdd = int64(binary.LittleEndian.Uint64(sectdata[rsect][rOff:]))
 317                                 }
 318
 319                         case sys.ARM:
 320                                 switch r.Type {
 321                                 default:
 322                                         return nil, nil, fmt.Errorf("%s: %v: unknown ARM relocation type %v", pn, sectsyms[rsect], r.Type)
 323
 324                                 case IMAGE_REL_ARM_SECREL:
 325                                         rType = objabi.R_PCREL
 326
 327                                         rAdd = int64(int32(binary.LittleEndian.Uint32(sectdata[rsect][rOff:])))
 328
 329                                 case IMAGE_REL_ARM_ADDR32, IMAGE_REL_ARM_ADDR32NB:
 330                                         rType = objabi.R_ADDR
 331
 332                                         rAdd = int64(int32(binary.LittleEndian.Uint32(sectdata[rsect][rOff:])))
 333
 334                                 case IMAGE_REL_ARM_BRANCH24:
 335                                         rType = objabi.R_CALLARM
 336
 337                                         rAdd = int64(int32(binary.LittleEndian.Uint32(sectdata[rsect][rOff:])))
 338                                 }
 339
 340                         case sys.ARM64:
 341                                 switch r.Type {
 342                                 default:
 343                                         return nil, nil, fmt.Errorf("%s: %v: unknown ARM64 relocation type %v", pn, sectsyms[rsect], r.Type)
 344
 345                                 case IMAGE_REL_ARM64_ADDR32, IMAGE_REL_ARM64_ADDR32NB:
 346                                         rType = objabi.R_ADDR
 347
 348                                         rAdd = int64(int32(binary.LittleEndian.Uint32(sectdata[rsect][rOff:])))
 349                                 }
 350                         }
 351
 352                         // ld -r could generate multiple section symbols for the
 353                         // same section but with different values, we have to take
 354                         // that into account, or in the case of split resources,
 355                         // the section and its symbols are split into two sections.
 356                         if issect(pesym) || splitResources {
 357                                 rAdd += int64(pesym.Value)
 358                         }
 359
 360                         rel, _ := sb.AddRel(rType)
 361                         rel.SetOff(rOff)
 362                         rel.SetSiz(rSize)
 363                         rel.SetSym(rSym)
 364                         rel.SetAdd(rAdd)
 365                 }
 366
 367                 sb.SortRelocs()
 368         }
 369
 370         // enter sub-symbols into symbol table.
 371         for i, numaux := 0, 0; i < len(f.COFFSymbols); i += numaux + 1 {
 372                 pesym := &f.COFFSymbols[i]
 373
 374                 numaux = int(pesym.NumberOfAuxSymbols)
 375
 376                 name, err := pesym.FullName(f.StringTable)
 377                 if err != nil {
 378                         return nil, nil, err
 379                 }
 380                 if name == "" {
 381                         continue
 382                 }
 383                 if issect(pesym) {
 384                         continue
 385                 }
 386                 if int(pesym.SectionNumber) > len(f.Sections) {
 387                         continue
 388                 }
 389                 if pesym.SectionNumber == IMAGE_SYM_DEBUG {
 390                         continue
 391                 }
 392                 if pesym.SectionNumber == IMAGE_SYM_ABSOLUTE && bytes.Equal(pesym.Name[:], []byte("@feat.00")) {
 393                         // Microsoft's linker looks at whether all input objects have an empty
 394                         // section called @feat.00. If all of them do, then it enables SEH;
 395                         // otherwise it doesn't enable that feature. So, since around the Windows
 396                         // XP SP2 era, most tools that make PE objects just tack on that section,
 397                         // so that it won't gimp Microsoft's linker logic. Go doesn't support SEH,
 398                         // so in theory, none of this really matters to us. But actually, if the
 399                         // linker tries to ingest an object with @feat.00 -- which are produced by
 400                         // LLVM's resource compiler, for example -- it chokes because of the
 401                         // IMAGE_SYM_ABSOLUTE section that it doesn't know how to deal with. Since
 402                         // @feat.00 is just a marking anyway, skip IMAGE_SYM_ABSOLUTE sections that
 403                         // are called @feat.00.
 404                         continue
 405                 }
 406                 var sect *pe.Section
 407                 if pesym.SectionNumber > 0 {
 408                         sect = f.Sections[pesym.SectionNumber-1]
 409                         if _, found := sectsyms[sect]; !found {
 410                                 continue
 411                         }
 412                 }
 413
 414                 bld, s, err := readpesym(l, arch, lookup, f, pesym, sectsyms, localSymVersion)
 415                 if err != nil {
 416                         return nil, nil, err
 417                 }
 418
 419                 if pesym.SectionNumber == 0 { // extern
 420                         if l.SymType(s) == sym.SDYNIMPORT {
 421                                 bld = makeUpdater(l, bld, s)
 422                                 bld.SetPlt(-2) // flag for dynimport in PE object files.
 423                         }
 424                         if l.SymType(s) == sym.SXREF && pesym.Value > 0 { // global data
 425                                 bld = makeUpdater(l, bld, s)
 426                                 bld.SetType(sym.SNOPTRDATA)
 427                                 bld.SetSize(int64(pesym.Value))
 428                         }
 429
 430                         continue
 431                 } else if pesym.SectionNumber > 0 && int(pesym.SectionNumber) <= len(f.Sections) {
 432                         sect = f.Sections[pesym.SectionNumber-1]
 433                         if _, found := sectsyms[sect]; !found {
 434                                 return nil, nil, fmt.Errorf("%s: %v: missing sect.sym", pn, s)
 435                         }
 436                 } else {
 437                         return nil, nil, fmt.Errorf("%s: %v: sectnum < 0!", pn, s)
 438                 }
 439
 440                 if sect == nil {
 441                         return nil, nil, nil
 442                 }
 443
 444                 if l.OuterSym(s) != 0 {
 445                         if l.AttrDuplicateOK(s) {
 446                                 continue
 447                         }
 448                         outerName := l.SymName(l.OuterSym(s))
 449                         sectName := l.SymName(sectsyms[sect])
 450                         return nil, nil, fmt.Errorf("%s: duplicate symbol reference: %s in both %s and %s", pn, l.SymName(s), outerName, sectName)
 451                 }
 452
 453                 bld = makeUpdater(l, bld, s)
 454                 sectsym := sectsyms[sect]
 455                 bld.SetType(l.SymType(sectsym))
 456                 l.AddInteriorSym(sectsym, s)
 457                 bld.SetValue(int64(pesym.Value))
 458                 bld.SetSize(4)
 459                 if l.SymType(sectsym) == sym.STEXT {
 460                         if bld.External() && !bld.DuplicateOK() {
 461                                 return nil, nil, fmt.Errorf("%s: duplicate symbol definition", l.SymName(s))
 462                         }
 463                         bld.SetExternal(true)
 464                 }
 465         }
 466
 467         // Sort outer lists by address, adding to textp.
 468         // This keeps textp in increasing address order.
 469         for _, sect := range f.Sections {
 470                 s := sectsyms[sect]
 471                 if s == 0 {
 472                         continue
 473                 }
 474                 l.SortSub(s)
 475                 if l.SymType(s) == sym.STEXT {
 476                         for ; s != 0; s = l.SubSym(s) {
 477                                 if l.AttrOnList(s) {
 478                                         return nil, nil, fmt.Errorf("symbol %s listed multiple times", l.SymName(s))
 479                                 }
 480                                 l.SetAttrOnList(s, true)
 481                                 textp = append(textp, s)
 482                         }
 483                 }
 484         }
 485
 486         return textp, rsrc, nil
 487 }
 488
 489 func issect(s *pe.COFFSymbol) bool {
 490         return s.StorageClass == IMAGE_SYM_CLASS_STATIC && s.Type == 0 && s.Name[0] == '.'
 491 }
 492
 493 func readpesym(l *loader.Loader, arch *sys.Arch, lookup func(string, int) loader.Sym, f *pe.File, pesym *pe.COFFSymbol, sectsyms map[*pe.Section]loader.Sym, localSymVersion int) (*loader.SymbolBuilder, loader.Sym, error) {
 494         symname, err := pesym.FullName(f.StringTable)
 495         if err != nil {
 496                 return nil, 0, err
 497         }
 498         var name string
 499         if issect(pesym) {
 500                 name = l.SymName(sectsyms[f.Sections[pesym.SectionNumber-1]])
 501         } else {
 502                 name = symname
 503                 switch arch.Family {
 504                 case sys.AMD64:
 505                         if name == "__imp___acrt_iob_func" {
 506                                 // Do not rename __imp___acrt_iob_func into __acrt_iob_func,
 507                                 // because __imp___acrt_iob_func symbol is real
 508                                 // (see commit b295099 from git://git.code.sf.net/p/mingw-w64/mingw-w64 for details).
 509                         } else {
 510                                 name = strings.TrimPrefix(name, "__imp_") // __imp_Name => Name
 511                         }
 512                 case sys.I386:
 513                         if name == "__imp____acrt_iob_func" {
 514                                 // Do not rename __imp____acrt_iob_func into ___acrt_iob_func,
 515                                 // because __imp____acrt_iob_func symbol is real
 516                                 // (see commit b295099 from git://git.code.sf.net/p/mingw-w64/mingw-w64 for details).
 517                         } else {
 518                                 name = strings.TrimPrefix(name, "__imp_") // __imp_Name => Name
 519                         }
 520                         if name[0] == '_' {
 521                                 name = name[1:] // _Name => Name
 522                         }
 523                 }
 524         }
 525
 526         // remove last @XXX
 527         if i := strings.LastIndex(name, "@"); i >= 0 {
 528                 name = name[:i]
 529         }
 530
 531         var s loader.Sym
 532         var bld *loader.SymbolBuilder
 533         switch pesym.Type {
 534         default:
 535                 return nil, 0, fmt.Errorf("%s: invalid symbol type %d", symname, pesym.Type)
 536
 537         case IMAGE_SYM_DTYPE_FUNCTION, IMAGE_SYM_DTYPE_NULL:
 538                 switch pesym.StorageClass {
 539                 case IMAGE_SYM_CLASS_EXTERNAL: //global
 540                         s = lookup(name, 0)
 541
 542                 case IMAGE_SYM_CLASS_NULL, IMAGE_SYM_CLASS_STATIC, IMAGE_SYM_CLASS_LABEL:
 543                         s = lookup(name, localSymVersion)
 544                         bld = makeUpdater(l, bld, s)
 545                         bld.SetDuplicateOK(true)
 546
 547                 default:
 548                         return nil, 0, fmt.Errorf("%s: invalid symbol binding %d", symname, pesym.StorageClass)
 549                 }
 550         }
 551
 552         if s != 0 && l.SymType(s) == 0 && (pesym.StorageClass != IMAGE_SYM_CLASS_STATIC || pesym.Value != 0) {
 553                 bld = makeUpdater(l, bld, s)
 554                 bld.SetType(sym.SXREF)
 555         }
 556         if strings.HasPrefix(symname, "__imp_") {
 557                 bld = makeUpdater(l, bld, s)
 558                 bld.SetGot(-2) // flag for __imp_
 559         }
 560
 561         return bld, s, nil
 562 }