github.com/gagliardetto/golang-go@v0.0.0-20201020153340-53909ea70814/cmd/link/internal/s390x/asm.go (about)

     1  // Inferno utils/5l/asm.c
     2  // https://bitbucket.org/inferno-os/inferno-os/src/default/utils/5l/asm.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  
    31  package s390x
    32  
    33  import (
    34  	"github.com/gagliardetto/golang-go/cmd/internal/objabi"
    35  	"github.com/gagliardetto/golang-go/cmd/internal/sys"
    36  	"github.com/gagliardetto/golang-go/cmd/link/internal/ld"
    37  	"github.com/gagliardetto/golang-go/cmd/link/internal/sym"
    38  	"debug/elf"
    39  	"fmt"
    40  )
    41  
    42  // gentext generates assembly to append the local moduledata to the global
    43  // moduledata linked list at initialization time. This is only done if the runtime
    44  // is in a different module.
    45  //
    46  // <go.link.addmoduledata>:
    47  // 	larl  %r2, <local.moduledata>
    48  // 	jg    <runtime.addmoduledata@plt>
    49  //	undef
    50  //
    51  // The job of appending the moduledata is delegated to runtime.addmoduledata.
    52  func gentext(ctxt *ld.Link) {
    53  	if !ctxt.DynlinkingGo() {
    54  		return
    55  	}
    56  	addmoduledata := ctxt.Syms.Lookup("runtime.addmoduledata", 0)
    57  	if addmoduledata.Type == sym.STEXT && ctxt.BuildMode != ld.BuildModePlugin {
    58  		// we're linking a module containing the runtime -> no need for
    59  		// an init function
    60  		return
    61  	}
    62  	addmoduledata.Attr |= sym.AttrReachable
    63  	initfunc := ctxt.Syms.Lookup("go.link.addmoduledata", 0)
    64  	initfunc.Type = sym.STEXT
    65  	initfunc.Attr |= sym.AttrLocal
    66  	initfunc.Attr |= sym.AttrReachable
    67  
    68  	// larl %r2, <local.moduledata>
    69  	initfunc.AddUint8(0xc0)
    70  	initfunc.AddUint8(0x20)
    71  	lmd := initfunc.AddRel()
    72  	lmd.InitExt()
    73  	lmd.Off = int32(initfunc.Size)
    74  	lmd.Siz = 4
    75  	lmd.Sym = ctxt.Moduledata
    76  	lmd.Type = objabi.R_PCREL
    77  	lmd.Variant = sym.RV_390_DBL
    78  	lmd.Add = 2 + int64(lmd.Siz)
    79  	initfunc.AddUint32(ctxt.Arch, 0)
    80  
    81  	// jg <runtime.addmoduledata[@plt]>
    82  	initfunc.AddUint8(0xc0)
    83  	initfunc.AddUint8(0xf4)
    84  	rel := initfunc.AddRel()
    85  	rel.InitExt()
    86  	rel.Off = int32(initfunc.Size)
    87  	rel.Siz = 4
    88  	rel.Sym = ctxt.Syms.Lookup("runtime.addmoduledata", 0)
    89  	rel.Type = objabi.R_CALL
    90  	rel.Variant = sym.RV_390_DBL
    91  	rel.Add = 2 + int64(rel.Siz)
    92  	initfunc.AddUint32(ctxt.Arch, 0)
    93  
    94  	// undef (for debugging)
    95  	initfunc.AddUint32(ctxt.Arch, 0)
    96  	if ctxt.BuildMode == ld.BuildModePlugin {
    97  		ctxt.Textp = append(ctxt.Textp, addmoduledata)
    98  	}
    99  	ctxt.Textp = append(ctxt.Textp, initfunc)
   100  	initarray_entry := ctxt.Syms.Lookup("go.link.addmoduledatainit", 0)
   101  	initarray_entry.Attr |= sym.AttrLocal
   102  	initarray_entry.Attr |= sym.AttrReachable
   103  	initarray_entry.Type = sym.SINITARR
   104  	initarray_entry.AddAddr(ctxt.Arch, initfunc)
   105  }
   106  
   107  func adddynrel(ctxt *ld.Link, s *sym.Symbol, r *sym.Reloc) bool {
   108  	targ := r.Sym
   109  	r.InitExt()
   110  
   111  	switch r.Type {
   112  	default:
   113  		if r.Type >= objabi.ElfRelocOffset {
   114  			ld.Errorf(s, "unexpected relocation type %d", r.Type)
   115  			return false
   116  		}
   117  
   118  		// Handle relocations found in ELF object files.
   119  	case objabi.ElfRelocOffset + objabi.RelocType(elf.R_390_12),
   120  		objabi.ElfRelocOffset + objabi.RelocType(elf.R_390_GOT12):
   121  		ld.Errorf(s, "s390x 12-bit relocations have not been implemented (relocation type %d)", r.Type-objabi.ElfRelocOffset)
   122  		return false
   123  
   124  	case objabi.ElfRelocOffset + objabi.RelocType(elf.R_390_8),
   125  		objabi.ElfRelocOffset + objabi.RelocType(elf.R_390_16),
   126  		objabi.ElfRelocOffset + objabi.RelocType(elf.R_390_32),
   127  		objabi.ElfRelocOffset + objabi.RelocType(elf.R_390_64):
   128  		if targ.Type == sym.SDYNIMPORT {
   129  			ld.Errorf(s, "unexpected R_390_nn relocation for dynamic symbol %s", targ.Name)
   130  		}
   131  		r.Type = objabi.R_ADDR
   132  		return true
   133  
   134  	case objabi.ElfRelocOffset + objabi.RelocType(elf.R_390_PC16),
   135  		objabi.ElfRelocOffset + objabi.RelocType(elf.R_390_PC32),
   136  		objabi.ElfRelocOffset + objabi.RelocType(elf.R_390_PC64):
   137  		if targ.Type == sym.SDYNIMPORT {
   138  			ld.Errorf(s, "unexpected R_390_PCnn relocation for dynamic symbol %s", targ.Name)
   139  		}
   140  		// TODO(mwhudson): the test of VisibilityHidden here probably doesn't make
   141  		// sense and should be removed when someone has thought about it properly.
   142  		if (targ.Type == 0 || targ.Type == sym.SXREF) && !targ.Attr.VisibilityHidden() {
   143  			ld.Errorf(s, "unknown symbol %s in pcrel", targ.Name)
   144  		}
   145  		r.Type = objabi.R_PCREL
   146  		r.Add += int64(r.Siz)
   147  		return true
   148  
   149  	case objabi.ElfRelocOffset + objabi.RelocType(elf.R_390_GOT16),
   150  		objabi.ElfRelocOffset + objabi.RelocType(elf.R_390_GOT32),
   151  		objabi.ElfRelocOffset + objabi.RelocType(elf.R_390_GOT64):
   152  		ld.Errorf(s, "unimplemented S390x relocation: %v", r.Type-objabi.ElfRelocOffset)
   153  		return true
   154  
   155  	case objabi.ElfRelocOffset + objabi.RelocType(elf.R_390_PLT16DBL),
   156  		objabi.ElfRelocOffset + objabi.RelocType(elf.R_390_PLT32DBL):
   157  		r.Type = objabi.R_PCREL
   158  		r.Variant = sym.RV_390_DBL
   159  		r.Add += int64(r.Siz)
   160  		if targ.Type == sym.SDYNIMPORT {
   161  			addpltsym(ctxt, targ)
   162  			r.Sym = ctxt.Syms.Lookup(".plt", 0)
   163  			r.Add += int64(targ.Plt())
   164  		}
   165  		return true
   166  
   167  	case objabi.ElfRelocOffset + objabi.RelocType(elf.R_390_PLT32),
   168  		objabi.ElfRelocOffset + objabi.RelocType(elf.R_390_PLT64):
   169  		r.Type = objabi.R_PCREL
   170  		r.Add += int64(r.Siz)
   171  		if targ.Type == sym.SDYNIMPORT {
   172  			addpltsym(ctxt, targ)
   173  			r.Sym = ctxt.Syms.Lookup(".plt", 0)
   174  			r.Add += int64(targ.Plt())
   175  		}
   176  		return true
   177  
   178  	case objabi.ElfRelocOffset + objabi.RelocType(elf.R_390_COPY):
   179  		ld.Errorf(s, "unimplemented S390x relocation: %v", r.Type-objabi.ElfRelocOffset)
   180  		return false
   181  
   182  	case objabi.ElfRelocOffset + objabi.RelocType(elf.R_390_GLOB_DAT):
   183  		ld.Errorf(s, "unimplemented S390x relocation: %v", r.Type-objabi.ElfRelocOffset)
   184  		return false
   185  
   186  	case objabi.ElfRelocOffset + objabi.RelocType(elf.R_390_JMP_SLOT):
   187  		ld.Errorf(s, "unimplemented S390x relocation: %v", r.Type-objabi.ElfRelocOffset)
   188  		return false
   189  
   190  	case objabi.ElfRelocOffset + objabi.RelocType(elf.R_390_RELATIVE):
   191  		ld.Errorf(s, "unimplemented S390x relocation: %v", r.Type-objabi.ElfRelocOffset)
   192  		return false
   193  
   194  	case objabi.ElfRelocOffset + objabi.RelocType(elf.R_390_GOTOFF):
   195  		if targ.Type == sym.SDYNIMPORT {
   196  			ld.Errorf(s, "unexpected R_390_GOTOFF relocation for dynamic symbol %s", targ.Name)
   197  		}
   198  		r.Type = objabi.R_GOTOFF
   199  		return true
   200  
   201  	case objabi.ElfRelocOffset + objabi.RelocType(elf.R_390_GOTPC):
   202  		r.Type = objabi.R_PCREL
   203  		r.Sym = ctxt.Syms.Lookup(".got", 0)
   204  		r.Add += int64(r.Siz)
   205  		return true
   206  
   207  	case objabi.ElfRelocOffset + objabi.RelocType(elf.R_390_PC16DBL),
   208  		objabi.ElfRelocOffset + objabi.RelocType(elf.R_390_PC32DBL):
   209  		r.Type = objabi.R_PCREL
   210  		r.Variant = sym.RV_390_DBL
   211  		r.Add += int64(r.Siz)
   212  		if targ.Type == sym.SDYNIMPORT {
   213  			ld.Errorf(s, "unexpected R_390_PCnnDBL relocation for dynamic symbol %s", targ.Name)
   214  		}
   215  		return true
   216  
   217  	case objabi.ElfRelocOffset + objabi.RelocType(elf.R_390_GOTPCDBL):
   218  		r.Type = objabi.R_PCREL
   219  		r.Variant = sym.RV_390_DBL
   220  		r.Sym = ctxt.Syms.Lookup(".got", 0)
   221  		r.Add += int64(r.Siz)
   222  		return true
   223  
   224  	case objabi.ElfRelocOffset + objabi.RelocType(elf.R_390_GOTENT):
   225  		addgotsym(ctxt, targ)
   226  
   227  		r.Type = objabi.R_PCREL
   228  		r.Variant = sym.RV_390_DBL
   229  		r.Sym = ctxt.Syms.Lookup(".got", 0)
   230  		r.Add += int64(targ.Got())
   231  		r.Add += int64(r.Siz)
   232  		return true
   233  	}
   234  	// Handle references to ELF symbols from our own object files.
   235  	if targ.Type != sym.SDYNIMPORT {
   236  		return true
   237  	}
   238  
   239  	return false
   240  }
   241  
   242  func elfreloc1(ctxt *ld.Link, r *sym.Reloc, sectoff int64) bool {
   243  	ctxt.Out.Write64(uint64(sectoff))
   244  
   245  	elfsym := r.Xsym.ElfsymForReloc()
   246  	switch r.Type {
   247  	default:
   248  		return false
   249  	case objabi.R_TLS_LE:
   250  		switch r.Siz {
   251  		default:
   252  			return false
   253  		case 4:
   254  			// WARNING - silently ignored by linker in ELF64
   255  			ctxt.Out.Write64(uint64(elf.R_390_TLS_LE32) | uint64(elfsym)<<32)
   256  		case 8:
   257  			// WARNING - silently ignored by linker in ELF32
   258  			ctxt.Out.Write64(uint64(elf.R_390_TLS_LE64) | uint64(elfsym)<<32)
   259  		}
   260  	case objabi.R_TLS_IE:
   261  		switch r.Siz {
   262  		default:
   263  			return false
   264  		case 4:
   265  			ctxt.Out.Write64(uint64(elf.R_390_TLS_IEENT) | uint64(elfsym)<<32)
   266  		}
   267  	case objabi.R_ADDR:
   268  		switch r.Siz {
   269  		default:
   270  			return false
   271  		case 4:
   272  			ctxt.Out.Write64(uint64(elf.R_390_32) | uint64(elfsym)<<32)
   273  		case 8:
   274  			ctxt.Out.Write64(uint64(elf.R_390_64) | uint64(elfsym)<<32)
   275  		}
   276  	case objabi.R_GOTPCREL:
   277  		if r.Siz == 4 {
   278  			ctxt.Out.Write64(uint64(elf.R_390_GOTENT) | uint64(elfsym)<<32)
   279  		} else {
   280  			return false
   281  		}
   282  	case objabi.R_PCREL, objabi.R_PCRELDBL, objabi.R_CALL:
   283  		elfrel := elf.R_390_NONE
   284  		isdbl := r.Variant&sym.RV_TYPE_MASK == sym.RV_390_DBL
   285  		// TODO(mundaym): all DBL style relocations should be
   286  		// signalled using the variant - see issue 14218.
   287  		switch r.Type {
   288  		case objabi.R_PCRELDBL, objabi.R_CALL:
   289  			isdbl = true
   290  		}
   291  		if r.Xsym.Type == sym.SDYNIMPORT && (r.Xsym.ElfType() == elf.STT_FUNC || r.Type == objabi.R_CALL) {
   292  			if isdbl {
   293  				switch r.Siz {
   294  				case 2:
   295  					elfrel = elf.R_390_PLT16DBL
   296  				case 4:
   297  					elfrel = elf.R_390_PLT32DBL
   298  				}
   299  			} else {
   300  				switch r.Siz {
   301  				case 4:
   302  					elfrel = elf.R_390_PLT32
   303  				case 8:
   304  					elfrel = elf.R_390_PLT64
   305  				}
   306  			}
   307  		} else {
   308  			if isdbl {
   309  				switch r.Siz {
   310  				case 2:
   311  					elfrel = elf.R_390_PC16DBL
   312  				case 4:
   313  					elfrel = elf.R_390_PC32DBL
   314  				}
   315  			} else {
   316  				switch r.Siz {
   317  				case 2:
   318  					elfrel = elf.R_390_PC16
   319  				case 4:
   320  					elfrel = elf.R_390_PC32
   321  				case 8:
   322  					elfrel = elf.R_390_PC64
   323  				}
   324  			}
   325  		}
   326  		if elfrel == elf.R_390_NONE {
   327  			return false // unsupported size/dbl combination
   328  		}
   329  		ctxt.Out.Write64(uint64(elfrel) | uint64(elfsym)<<32)
   330  	}
   331  
   332  	ctxt.Out.Write64(uint64(r.Xadd))
   333  	return true
   334  }
   335  
   336  func elfsetupplt(ctxt *ld.Link) {
   337  	plt := ctxt.Syms.Lookup(".plt", 0)
   338  	got := ctxt.Syms.Lookup(".got", 0)
   339  	if plt.Size == 0 {
   340  		// stg     %r1,56(%r15)
   341  		plt.AddUint8(0xe3)
   342  		plt.AddUint8(0x10)
   343  		plt.AddUint8(0xf0)
   344  		plt.AddUint8(0x38)
   345  		plt.AddUint8(0x00)
   346  		plt.AddUint8(0x24)
   347  		// larl    %r1,_GLOBAL_OFFSET_TABLE_
   348  		plt.AddUint8(0xc0)
   349  		plt.AddUint8(0x10)
   350  		plt.AddPCRelPlus(ctxt.Arch, got, 6)
   351  		// mvc     48(8,%r15),8(%r1)
   352  		plt.AddUint8(0xd2)
   353  		plt.AddUint8(0x07)
   354  		plt.AddUint8(0xf0)
   355  		plt.AddUint8(0x30)
   356  		plt.AddUint8(0x10)
   357  		plt.AddUint8(0x08)
   358  		// lg      %r1,16(%r1)
   359  		plt.AddUint8(0xe3)
   360  		plt.AddUint8(0x10)
   361  		plt.AddUint8(0x10)
   362  		plt.AddUint8(0x10)
   363  		plt.AddUint8(0x00)
   364  		plt.AddUint8(0x04)
   365  		// br      %r1
   366  		plt.AddUint8(0x07)
   367  		plt.AddUint8(0xf1)
   368  		// nopr    %r0
   369  		plt.AddUint8(0x07)
   370  		plt.AddUint8(0x00)
   371  		// nopr    %r0
   372  		plt.AddUint8(0x07)
   373  		plt.AddUint8(0x00)
   374  		// nopr    %r0
   375  		plt.AddUint8(0x07)
   376  		plt.AddUint8(0x00)
   377  
   378  		// assume got->size == 0 too
   379  		got.AddAddrPlus(ctxt.Arch, ctxt.Syms.Lookup(".dynamic", 0), 0)
   380  
   381  		got.AddUint64(ctxt.Arch, 0)
   382  		got.AddUint64(ctxt.Arch, 0)
   383  	}
   384  }
   385  
   386  func machoreloc1(arch *sys.Arch, out *ld.OutBuf, s *sym.Symbol, r *sym.Reloc, sectoff int64) bool {
   387  	return false
   388  }
   389  
   390  func archreloc(ctxt *ld.Link, r *sym.Reloc, s *sym.Symbol, val int64) (int64, bool) {
   391  	if ctxt.LinkMode == ld.LinkExternal {
   392  		return val, false
   393  	}
   394  
   395  	switch r.Type {
   396  	case objabi.R_CONST:
   397  		return r.Add, true
   398  	case objabi.R_GOTOFF:
   399  		return ld.Symaddr(r.Sym) + r.Add - ld.Symaddr(ctxt.Syms.Lookup(".got", 0)), true
   400  	}
   401  
   402  	return val, false
   403  }
   404  
   405  func archrelocvariant(ctxt *ld.Link, r *sym.Reloc, s *sym.Symbol, t int64) int64 {
   406  	switch r.Variant & sym.RV_TYPE_MASK {
   407  	default:
   408  		ld.Errorf(s, "unexpected relocation variant %d", r.Variant)
   409  		return t
   410  
   411  	case sym.RV_NONE:
   412  		return t
   413  
   414  	case sym.RV_390_DBL:
   415  		if (t & 1) != 0 {
   416  			ld.Errorf(s, "%s+%v is not 2-byte aligned", r.Sym.Name, r.Sym.Value)
   417  		}
   418  		return t >> 1
   419  	}
   420  }
   421  
   422  func addpltsym(ctxt *ld.Link, s *sym.Symbol) {
   423  	if s.Plt() >= 0 {
   424  		return
   425  	}
   426  
   427  	ld.Adddynsym(ctxt, s)
   428  
   429  	if ctxt.IsELF {
   430  		plt := ctxt.Syms.Lookup(".plt", 0)
   431  		got := ctxt.Syms.Lookup(".got", 0)
   432  		rela := ctxt.Syms.Lookup(".rela.plt", 0)
   433  		if plt.Size == 0 {
   434  			elfsetupplt(ctxt)
   435  		}
   436  		// larl    %r1,_GLOBAL_OFFSET_TABLE_+index
   437  
   438  		plt.AddUint8(0xc0)
   439  		plt.AddUint8(0x10)
   440  		plt.AddPCRelPlus(ctxt.Arch, got, got.Size+6) // need variant?
   441  
   442  		// add to got: pointer to current pos in plt
   443  		got.AddAddrPlus(ctxt.Arch, plt, plt.Size+8) // weird but correct
   444  		// lg      %r1,0(%r1)
   445  		plt.AddUint8(0xe3)
   446  		plt.AddUint8(0x10)
   447  		plt.AddUint8(0x10)
   448  		plt.AddUint8(0x00)
   449  		plt.AddUint8(0x00)
   450  		plt.AddUint8(0x04)
   451  		// br      %r1
   452  		plt.AddUint8(0x07)
   453  		plt.AddUint8(0xf1)
   454  		// basr    %r1,%r0
   455  		plt.AddUint8(0x0d)
   456  		plt.AddUint8(0x10)
   457  		// lgf     %r1,12(%r1)
   458  		plt.AddUint8(0xe3)
   459  		plt.AddUint8(0x10)
   460  		plt.AddUint8(0x10)
   461  		plt.AddUint8(0x0c)
   462  		plt.AddUint8(0x00)
   463  		plt.AddUint8(0x14)
   464  		// jg .plt
   465  		plt.AddUint8(0xc0)
   466  		plt.AddUint8(0xf4)
   467  
   468  		plt.AddUint32(ctxt.Arch, uint32(-((plt.Size - 2) >> 1))) // roll-your-own relocation
   469  		//.plt index
   470  		plt.AddUint32(ctxt.Arch, uint32(rela.Size)) // rela size before current entry
   471  
   472  		// rela
   473  		rela.AddAddrPlus(ctxt.Arch, got, got.Size-8)
   474  
   475  		rela.AddUint64(ctxt.Arch, ld.ELF64_R_INFO(uint32(s.Dynid), uint32(elf.R_390_JMP_SLOT)))
   476  		rela.AddUint64(ctxt.Arch, 0)
   477  
   478  		s.SetPlt(int32(plt.Size - 32))
   479  
   480  	} else {
   481  		ld.Errorf(s, "addpltsym: unsupported binary format")
   482  	}
   483  }
   484  
   485  func addgotsym(ctxt *ld.Link, s *sym.Symbol) {
   486  	if s.Got() >= 0 {
   487  		return
   488  	}
   489  
   490  	ld.Adddynsym(ctxt, s)
   491  	got := ctxt.Syms.Lookup(".got", 0)
   492  	s.SetGot(int32(got.Size))
   493  	got.AddUint64(ctxt.Arch, 0)
   494  
   495  	if ctxt.IsELF {
   496  		rela := ctxt.Syms.Lookup(".rela", 0)
   497  		rela.AddAddrPlus(ctxt.Arch, got, int64(s.Got()))
   498  		rela.AddUint64(ctxt.Arch, ld.ELF64_R_INFO(uint32(s.Dynid), uint32(elf.R_390_GLOB_DAT)))
   499  		rela.AddUint64(ctxt.Arch, 0)
   500  	} else {
   501  		ld.Errorf(s, "addgotsym: unsupported binary format")
   502  	}
   503  }
   504  
   505  func asmb(ctxt *ld.Link) {
   506  	if ctxt.IsELF {
   507  		ld.Asmbelfsetup()
   508  	}
   509  
   510  	sect := ld.Segtext.Sections[0]
   511  	ctxt.Out.SeekSet(int64(sect.Vaddr - ld.Segtext.Vaddr + ld.Segtext.Fileoff))
   512  	ld.Codeblk(ctxt, int64(sect.Vaddr), int64(sect.Length))
   513  	for _, sect = range ld.Segtext.Sections[1:] {
   514  		ctxt.Out.SeekSet(int64(sect.Vaddr - ld.Segtext.Vaddr + ld.Segtext.Fileoff))
   515  		ld.Datblk(ctxt, int64(sect.Vaddr), int64(sect.Length))
   516  	}
   517  
   518  	if ld.Segrodata.Filelen > 0 {
   519  		ctxt.Out.SeekSet(int64(ld.Segrodata.Fileoff))
   520  		ld.Datblk(ctxt, int64(ld.Segrodata.Vaddr), int64(ld.Segrodata.Filelen))
   521  	}
   522  	if ld.Segrelrodata.Filelen > 0 {
   523  		ctxt.Out.SeekSet(int64(ld.Segrelrodata.Fileoff))
   524  		ld.Datblk(ctxt, int64(ld.Segrelrodata.Vaddr), int64(ld.Segrelrodata.Filelen))
   525  	}
   526  
   527  	ctxt.Out.SeekSet(int64(ld.Segdata.Fileoff))
   528  	ld.Datblk(ctxt, int64(ld.Segdata.Vaddr), int64(ld.Segdata.Filelen))
   529  
   530  	ctxt.Out.SeekSet(int64(ld.Segdwarf.Fileoff))
   531  	ld.Dwarfblk(ctxt, int64(ld.Segdwarf.Vaddr), int64(ld.Segdwarf.Filelen))
   532  }
   533  
   534  func asmb2(ctxt *ld.Link) {
   535  	/* output symbol table */
   536  	ld.Symsize = 0
   537  
   538  	ld.Lcsize = 0
   539  	symo := uint32(0)
   540  	if !*ld.FlagS {
   541  		if !ctxt.IsELF {
   542  			ld.Errorf(nil, "unsupported executable format")
   543  		}
   544  		symo = uint32(ld.Segdwarf.Fileoff + ld.Segdwarf.Filelen)
   545  		symo = uint32(ld.Rnd(int64(symo), int64(*ld.FlagRound)))
   546  
   547  		ctxt.Out.SeekSet(int64(symo))
   548  		ld.Asmelfsym(ctxt)
   549  		ctxt.Out.Flush()
   550  		ctxt.Out.Write(ld.Elfstrdat)
   551  
   552  		if ctxt.LinkMode == ld.LinkExternal {
   553  			ld.Elfemitreloc(ctxt)
   554  		}
   555  	}
   556  
   557  	ctxt.Out.SeekSet(0)
   558  	switch ctxt.HeadType {
   559  	default:
   560  		ld.Errorf(nil, "unsupported operating system")
   561  	case objabi.Hlinux:
   562  		ld.Asmbelf(ctxt, int64(symo))
   563  	}
   564  
   565  	ctxt.Out.Flush()
   566  	if *ld.FlagC {
   567  		fmt.Printf("textsize=%d\n", ld.Segtext.Filelen)
   568  		fmt.Printf("datsize=%d\n", ld.Segdata.Filelen)
   569  		fmt.Printf("bsssize=%d\n", ld.Segdata.Length-ld.Segdata.Filelen)
   570  		fmt.Printf("symsize=%d\n", ld.Symsize)
   571  		fmt.Printf("lcsize=%d\n", ld.Lcsize)
   572  		fmt.Printf("total=%d\n", ld.Segtext.Filelen+ld.Segdata.Length+uint64(ld.Symsize)+uint64(ld.Lcsize))
   573  	}
   574  }