github.com/ltltlt/go-source-code@v0.0.0-20190830023027-95be009773aa/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  	"cmd/internal/objabi"
    36  	"cmd/internal/sys"
    37  	"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  func (ctxt *Link) computeTLSOffset() {
    65  	switch ctxt.HeadType {
    66  	default:
    67  		log.Fatalf("unknown thread-local storage offset for %v", ctxt.HeadType)
    68  
    69  	case objabi.Hplan9, objabi.Hwindows:
    70  		break
    71  
    72  		/*
    73  		 * ELF uses TLS offset negative from FS.
    74  		 * Translate 0(FS) and 8(FS) into -16(FS) and -8(FS).
    75  		 * Known to low-level assembly in package runtime and runtime/cgo.
    76  		 */
    77  	case objabi.Hlinux,
    78  		objabi.Hfreebsd,
    79  		objabi.Hnetbsd,
    80  		objabi.Hopenbsd,
    81  		objabi.Hdragonfly,
    82  		objabi.Hsolaris:
    83  		if objabi.GOOS == "android" {
    84  			switch ctxt.Arch.Family {
    85  			case sys.AMD64:
    86  				// Android/amd64 constant - offset from 0(FS) to our TLS slot.
    87  				// Explained in src/runtime/cgo/gcc_android_*.c
    88  				ctxt.Tlsoffset = 0x1d0
    89  			case sys.I386:
    90  				// Android/386 constant - offset from 0(GS) to our TLS slot.
    91  				ctxt.Tlsoffset = 0xf8
    92  			default:
    93  				ctxt.Tlsoffset = -1 * ctxt.Arch.PtrSize
    94  			}
    95  		} else {
    96  			ctxt.Tlsoffset = -1 * ctxt.Arch.PtrSize
    97  		}
    98  
    99  	case objabi.Hnacl:
   100  		switch ctxt.Arch.Family {
   101  		default:
   102  			log.Fatalf("unknown thread-local storage offset for nacl/%s", ctxt.Arch.Name)
   103  
   104  		case sys.ARM:
   105  			ctxt.Tlsoffset = 0
   106  
   107  		case sys.AMD64:
   108  			ctxt.Tlsoffset = 0
   109  
   110  		case sys.I386:
   111  			ctxt.Tlsoffset = -8
   112  		}
   113  
   114  		/*
   115  		 * OS X system constants - offset from 0(GS) to our TLS.
   116  		 * Explained in src/runtime/cgo/gcc_darwin_*.c.
   117  		 */
   118  	case objabi.Hdarwin:
   119  		switch ctxt.Arch.Family {
   120  		default:
   121  			log.Fatalf("unknown thread-local storage offset for darwin/%s", ctxt.Arch.Name)
   122  
   123  		case sys.ARM:
   124  			ctxt.Tlsoffset = 0 // dummy value, not needed
   125  
   126  		case sys.AMD64:
   127  			ctxt.Tlsoffset = 0x8a0
   128  
   129  		case sys.ARM64:
   130  			ctxt.Tlsoffset = 0 // dummy value, not needed
   131  
   132  		case sys.I386:
   133  			ctxt.Tlsoffset = 0x468
   134  		}
   135  	}
   136  
   137  }