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

     1  // Derived from Inferno utils/6l/obj.c and utils/6l/span.c
     2  // https://bitbucket.org/inferno-os/inferno-os/src/default/utils/6l/obj.c
     3  // https://bitbucket.org/inferno-os/inferno-os/src/default/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 ld
    33  
    34  import (
    35  	"github.com/gagliardetto/golang-go/cmd/internal/objabi"
    36  	"github.com/gagliardetto/golang-go/cmd/internal/sys"
    37  	"github.com/gagliardetto/golang-go/cmd/link/internal/sym"
    38  	"log"
    39  )
    40  
    41  func linknew(arch *sys.Arch) *Link {
    42  	ctxt := &Link{
    43  		Syms:         sym.NewSymbols(),
    44  		Out:          &OutBuf{arch: arch},
    45  		Arch:         arch,
    46  		LibraryByPkg: make(map[string]*sym.Library),
    47  	}
    48  
    49  	if objabi.GOARCH != arch.Name {
    50  		log.Fatalf("invalid objabi.GOARCH %s (want %s)", objabi.GOARCH, arch.Name)
    51  	}
    52  
    53  	AtExit(func() {
    54  		if nerrors > 0 && ctxt.Out.f != nil {
    55  			ctxt.Out.f.Close()
    56  			mayberemoveoutfile()
    57  		}
    58  	})
    59  
    60  	return ctxt
    61  }
    62  
    63  // computeTLSOffset records the thread-local storage offset.
    64  // Not used for Android where the TLS offset is determined at runtime.
    65  func (ctxt *Link) computeTLSOffset() {
    66  	switch ctxt.HeadType {
    67  	default:
    68  		log.Fatalf("unknown thread-local storage offset for %v", ctxt.HeadType)
    69  
    70  	case objabi.Hplan9, objabi.Hwindows, objabi.Hjs, objabi.Haix:
    71  		break
    72  
    73  	case objabi.Hlinux,
    74  		objabi.Hfreebsd,
    75  		objabi.Hnetbsd,
    76  		objabi.Hopenbsd,
    77  		objabi.Hdragonfly,
    78  		objabi.Hsolaris:
    79  		/*
    80  		 * ELF uses TLS offset negative from FS.
    81  		 * Translate 0(FS) and 8(FS) into -16(FS) and -8(FS).
    82  		 * Known to low-level assembly in package runtime and runtime/cgo.
    83  		 */
    84  		ctxt.Tlsoffset = -1 * ctxt.Arch.PtrSize
    85  
    86  	case objabi.Hdarwin:
    87  		/*
    88  		 * OS X system constants - offset from 0(GS) to our TLS.
    89  		 */
    90  		switch ctxt.Arch.Family {
    91  		default:
    92  			log.Fatalf("unknown thread-local storage offset for darwin/%s", ctxt.Arch.Name)
    93  
    94  			/*
    95  			 * For x86, Apple has reserved a slot in the TLS for Go. See issue 23617.
    96  			 * That slot is at offset 0x30 on amd64, and 0x18 on 386.
    97  			 * The slot will hold the G pointer.
    98  			 * These constants should match those in runtime/sys_darwin_{386,amd64}.s
    99  			 * and runtime/cgo/gcc_darwin_{386,amd64}.c.
   100  			 */
   101  		case sys.I386:
   102  			ctxt.Tlsoffset = 0x18
   103  
   104  		case sys.AMD64:
   105  			ctxt.Tlsoffset = 0x30
   106  
   107  		case sys.ARM:
   108  			ctxt.Tlsoffset = 0 // dummy value, not needed
   109  
   110  		case sys.ARM64:
   111  			ctxt.Tlsoffset = 0 // dummy value, not needed
   112  		}
   113  	}
   114  
   115  }