github.com/dannin/go@v0.0.0-20161031215817-d35dfd405eaa/src/cmd/link/internal/ld/symbols.go (about)

     1  // Derived from Inferno utils/6l/l.h and related files.
     2  // https://bitbucket.org/inferno-os/inferno-os/src/default/utils/6l/l.h
     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 ld
    32  
    33  type Symbols struct {
    34  	symbolBatch []Symbol
    35  
    36  	// Symbol lookup based on name and indexed by version.
    37  	hash []map[string]*Symbol
    38  
    39  	Allsym []*Symbol
    40  }
    41  
    42  func (syms *Symbols) newsym(name string, v int) *Symbol {
    43  	batch := syms.symbolBatch
    44  	if len(batch) == 0 {
    45  		batch = make([]Symbol, 1000)
    46  	}
    47  	s := &batch[0]
    48  	syms.symbolBatch = batch[1:]
    49  
    50  	s.Dynid = -1
    51  	s.Plt = -1
    52  	s.Got = -1
    53  	s.Name = name
    54  	s.Version = int16(v)
    55  	syms.Allsym = append(syms.Allsym, s)
    56  
    57  	return s
    58  }
    59  
    60  // Look up the symbol with the given name and version, creating the
    61  // symbol if it is not found.
    62  func (syms *Symbols) Lookup(name string, v int) *Symbol {
    63  	m := syms.hash[v]
    64  	s := m[name]
    65  	if s != nil {
    66  		return s
    67  	}
    68  	s = syms.newsym(name, v)
    69  	s.Extname = s.Name
    70  	m[name] = s
    71  	return s
    72  }
    73  
    74  // Look up the symbol with the given name and version, returning nil
    75  // if it is not found.
    76  func (syms *Symbols) ROLookup(name string, v int) *Symbol {
    77  	return syms.hash[v][name]
    78  }
    79  
    80  // Allocate a new version (i.e. symbol namespace).
    81  func (syms *Symbols) IncVersion() int {
    82  	syms.hash = append(syms.hash, make(map[string]*Symbol))
    83  	return len(syms.hash) - 1
    84  }