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Source file src/cmd/link/internal/ld/ld.go

Documentation: cmd/link/internal/ld

     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/link/internal/sym"
    36  	"io/ioutil"
    37  	"log"
    38  	"os"
    39  	"path"
    40  	"path/filepath"
    41  	"strconv"
    42  	"strings"
    43  )
    44  
    45  func (ctxt *Link) readImportCfg(file string) {
    46  	ctxt.PackageFile = make(map[string]string)
    47  	ctxt.PackageShlib = make(map[string]string)
    48  	data, err := ioutil.ReadFile(file)
    49  	if err != nil {
    50  		log.Fatalf("-importcfg: %v", err)
    51  	}
    52  
    53  	for lineNum, line := range strings.Split(string(data), "\n") {
    54  		lineNum++ // 1-based
    55  		line = strings.TrimSpace(line)
    56  		if line == "" {
    57  			continue
    58  		}
    59  		if line == "" || strings.HasPrefix(line, "#") {
    60  			continue
    61  		}
    62  
    63  		var verb, args string
    64  		if i := strings.Index(line, " "); i < 0 {
    65  			verb = line
    66  		} else {
    67  			verb, args = line[:i], strings.TrimSpace(line[i+1:])
    68  		}
    69  		var before, after string
    70  		if i := strings.Index(args, "="); i >= 0 {
    71  			before, after = args[:i], args[i+1:]
    72  		}
    73  		switch verb {
    74  		default:
    75  			log.Fatalf("%s:%d: unknown directive %q", file, lineNum, verb)
    76  		case "packagefile":
    77  			if before == "" || after == "" {
    78  				log.Fatalf(`%s:%d: invalid packagefile: syntax is "packagefile path=filename"`, file, lineNum)
    79  			}
    80  			ctxt.PackageFile[before] = after
    81  		case "packageshlib":
    82  			if before == "" || after == "" {
    83  				log.Fatalf(`%s:%d: invalid packageshlib: syntax is "packageshlib path=filename"`, file, lineNum)
    84  			}
    85  			ctxt.PackageShlib[before] = after
    86  		}
    87  	}
    88  }
    89  
    90  func pkgname(ctxt *Link, lib string) string {
    91  	name := path.Clean(lib)
    92  
    93  	// When using importcfg, we have the final package name.
    94  	if ctxt.PackageFile != nil {
    95  		return name
    96  	}
    97  
    98  	// runtime.a -> runtime, runtime.6 -> runtime
    99  	pkg := name
   100  	if len(pkg) >= 2 && pkg[len(pkg)-2] == '.' {
   101  		pkg = pkg[:len(pkg)-2]
   102  	}
   103  	return pkg
   104  }
   105  
   106  func findlib(ctxt *Link, lib string) (string, bool) {
   107  	name := path.Clean(lib)
   108  
   109  	var pname string
   110  	isshlib := false
   111  
   112  	if ctxt.linkShared && ctxt.PackageShlib[name] != "" {
   113  		pname = ctxt.PackageShlib[name]
   114  		isshlib = true
   115  	} else if ctxt.PackageFile != nil {
   116  		pname = ctxt.PackageFile[name]
   117  		if pname == "" {
   118  			ctxt.Logf("cannot find package %s (using -importcfg)\n", name)
   119  			return "", false
   120  		}
   121  	} else {
   122  		if filepath.IsAbs(name) {
   123  			pname = name
   124  		} else {
   125  			pkg := pkgname(ctxt, lib)
   126  			// Add .a if needed; the new -importcfg modes
   127  			// do not put .a into the package name anymore.
   128  			// This only matters when people try to mix
   129  			// compiles using -importcfg with links not using -importcfg,
   130  			// such as when running quick things like
   131  			// 'go tool compile x.go && go tool link x.o'
   132  			// by hand against a standard library built using -importcfg.
   133  			if !strings.HasSuffix(name, ".a") && !strings.HasSuffix(name, ".o") {
   134  				name += ".a"
   135  			}
   136  			// try dot, -L "libdir", and then goroot.
   137  			for _, dir := range ctxt.Libdir {
   138  				if ctxt.linkShared {
   139  					pname = dir + "/" + pkg + ".shlibname"
   140  					if _, err := os.Stat(pname); err == nil {
   141  						isshlib = true
   142  						break
   143  					}
   144  				}
   145  				pname = dir + "/" + name
   146  				if _, err := os.Stat(pname); err == nil {
   147  					break
   148  				}
   149  			}
   150  		}
   151  		pname = path.Clean(pname)
   152  	}
   153  
   154  	return pname, isshlib
   155  }
   156  
   157  func addlib(ctxt *Link, src string, obj string, lib string) *sym.Library {
   158  	pkg := pkgname(ctxt, lib)
   159  
   160  	// already loaded?
   161  	if l := ctxt.LibraryByPkg[pkg]; l != nil {
   162  		return l
   163  	}
   164  
   165  	pname, isshlib := findlib(ctxt, lib)
   166  
   167  	if ctxt.Debugvlog > 1 {
   168  		ctxt.Logf("%5.2f addlib: %s %s pulls in %s isshlib %v\n", elapsed(), obj, src, pname, isshlib)
   169  	}
   170  
   171  	if isshlib {
   172  		return addlibpath(ctxt, src, obj, "", pkg, pname)
   173  	}
   174  	return addlibpath(ctxt, src, obj, pname, pkg, "")
   175  }
   176  
   177  /*
   178   * add library to library list, return added library.
   179   *	srcref: src file referring to package
   180   *	objref: object file referring to package
   181   *	file: object file, e.g., /home/rsc/go/pkg/container/vector.a
   182   *	pkg: package import path, e.g. container/vector
   183   *	shlib: path to shared library, or .shlibname file holding path
   184   */
   185  func addlibpath(ctxt *Link, srcref string, objref string, file string, pkg string, shlib string) *sym.Library {
   186  	if l := ctxt.LibraryByPkg[pkg]; l != nil {
   187  		return l
   188  	}
   189  
   190  	if ctxt.Debugvlog > 1 {
   191  		ctxt.Logf("%5.2f addlibpath: srcref: %s objref: %s file: %s pkg: %s shlib: %s\n", Cputime(), srcref, objref, file, pkg, shlib)
   192  	}
   193  
   194  	l := &sym.Library{}
   195  	ctxt.LibraryByPkg[pkg] = l
   196  	ctxt.Library = append(ctxt.Library, l)
   197  	l.Objref = objref
   198  	l.Srcref = srcref
   199  	l.File = file
   200  	l.Pkg = pkg
   201  	if shlib != "" {
   202  		if strings.HasSuffix(shlib, ".shlibname") {
   203  			data, err := ioutil.ReadFile(shlib)
   204  			if err != nil {
   205  				Errorf(nil, "cannot read %s: %v", shlib, err)
   206  			}
   207  			shlib = strings.TrimSpace(string(data))
   208  		}
   209  		l.Shlib = shlib
   210  	}
   211  	return l
   212  }
   213  
   214  func atolwhex(s string) int64 {
   215  	n, _ := strconv.ParseInt(s, 0, 64)
   216  	return n
   217  }
   218  

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