github.com/sanprasirt/go@v0.0.0-20170607001320-a027466e4b6d/src/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  	"log"
    38  )
    39  
    40  func linknew(arch *sys.Arch) *Link {
    41  	ctxt := &Link{
    42  		Syms: &Symbols{
    43  			hash: []map[string]*Symbol{
    44  				// preallocate about 2mb for hash of
    45  				// non static symbols
    46  				make(map[string]*Symbol, 100000),
    47  			},
    48  			Allsym: make([]*Symbol, 0, 100000),
    49  		},
    50  		Arch:         arch,
    51  		LibraryByPkg: make(map[string]*Library),
    52  	}
    53  
    54  	if objabi.GOARCH != arch.Name {
    55  		log.Fatalf("invalid objabi.GOARCH %s (want %s)", objabi.GOARCH, arch.Name)
    56  	}
    57  
    58  	return ctxt
    59  }
    60  
    61  // computeTLSOffset records the thread-local storage offset.
    62  func (ctxt *Link) computeTLSOffset() {
    63  	switch Headtype {
    64  	default:
    65  		log.Fatalf("unknown thread-local storage offset for %v", Headtype)
    66  
    67  	case objabi.Hplan9, objabi.Hwindows:
    68  		break
    69  
    70  		/*
    71  		 * ELF uses TLS offset negative from FS.
    72  		 * Translate 0(FS) and 8(FS) into -16(FS) and -8(FS).
    73  		 * Known to low-level assembly in package runtime and runtime/cgo.
    74  		 */
    75  	case objabi.Hlinux,
    76  		objabi.Hfreebsd,
    77  		objabi.Hnetbsd,
    78  		objabi.Hopenbsd,
    79  		objabi.Hdragonfly,
    80  		objabi.Hsolaris:
    81  		if objabi.GOOS == "android" {
    82  			switch ctxt.Arch.Family {
    83  			case sys.AMD64:
    84  				// Android/amd64 constant - offset from 0(FS) to our TLS slot.
    85  				// Explained in src/runtime/cgo/gcc_android_*.c
    86  				ctxt.Tlsoffset = 0x1d0
    87  			case sys.I386:
    88  				// Android/386 constant - offset from 0(GS) to our TLS slot.
    89  				ctxt.Tlsoffset = 0xf8
    90  			default:
    91  				ctxt.Tlsoffset = -1 * ctxt.Arch.PtrSize
    92  			}
    93  		} else {
    94  			ctxt.Tlsoffset = -1 * ctxt.Arch.PtrSize
    95  		}
    96  
    97  	case objabi.Hnacl:
    98  		switch ctxt.Arch.Family {
    99  		default:
   100  			log.Fatalf("unknown thread-local storage offset for nacl/%s", ctxt.Arch.Name)
   101  
   102  		case sys.ARM:
   103  			ctxt.Tlsoffset = 0
   104  
   105  		case sys.AMD64:
   106  			ctxt.Tlsoffset = 0
   107  
   108  		case sys.I386:
   109  			ctxt.Tlsoffset = -8
   110  		}
   111  
   112  		/*
   113  		 * OS X system constants - offset from 0(GS) to our TLS.
   114  		 * Explained in src/runtime/cgo/gcc_darwin_*.c.
   115  		 */
   116  	case objabi.Hdarwin:
   117  		switch ctxt.Arch.Family {
   118  		default:
   119  			log.Fatalf("unknown thread-local storage offset for darwin/%s", ctxt.Arch.Name)
   120  
   121  		case sys.ARM:
   122  			ctxt.Tlsoffset = 0 // dummy value, not needed
   123  
   124  		case sys.AMD64:
   125  			ctxt.Tlsoffset = 0x8a0
   126  
   127  		case sys.ARM64:
   128  			ctxt.Tlsoffset = 0 // dummy value, not needed
   129  
   130  		case sys.I386:
   131  			ctxt.Tlsoffset = 0x468
   132  		}
   133  	}
   134  
   135  }