github.com/gagliardetto/golang-go@v0.0.0-20201020153340-53909ea70814/cmd/link/internal/sym/symkind.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 sym
    32  
    33  // A SymKind describes the kind of memory represented by a symbol.
    34  type SymKind uint8
    35  
    36  // Defined SymKind values.
    37  //
    38  // TODO(rsc): Give idiomatic Go names.
    39  //go:generate stringer -type=SymKind
    40  const (
    41  	Sxxx SymKind = iota
    42  	STEXT
    43  	SELFRXSECT
    44  
    45  	// Read-only sections.
    46  	STYPE
    47  	SSTRING
    48  	SGOSTRING
    49  	SGOFUNC
    50  	SGCBITS
    51  	SRODATA
    52  	SFUNCTAB
    53  
    54  	SELFROSECT
    55  	SMACHOPLT
    56  
    57  	// Read-only sections with relocations.
    58  	//
    59  	// Types STYPE-SFUNCTAB above are written to the .rodata section by default.
    60  	// When linking a shared object, some conceptually "read only" types need to
    61  	// be written to by relocations and putting them in a section called
    62  	// ".rodata" interacts poorly with the system linkers. The GNU linkers
    63  	// support this situation by arranging for sections of the name
    64  	// ".data.rel.ro.XXX" to be mprotected read only by the dynamic linker after
    65  	// relocations have applied, so when the Go linker is creating a shared
    66  	// object it checks all objects of the above types and bumps any object that
    67  	// has a relocation to it to the corresponding type below, which are then
    68  	// written to sections with appropriate magic names.
    69  	STYPERELRO
    70  	SSTRINGRELRO
    71  	SGOSTRINGRELRO
    72  	SGOFUNCRELRO
    73  	SGCBITSRELRO
    74  	SRODATARELRO
    75  	SFUNCTABRELRO
    76  
    77  	// Part of .data.rel.ro if it exists, otherwise part of .rodata.
    78  	STYPELINK
    79  	SITABLINK
    80  	SSYMTAB
    81  	SPCLNTAB
    82  
    83  	// Writable sections.
    84  	SFirstWritable
    85  	SBUILDINFO
    86  	SELFSECT
    87  	SMACHO
    88  	SMACHOGOT
    89  	SWINDOWS
    90  	SELFGOT
    91  	SNOPTRDATA
    92  	SINITARR
    93  	SDATA
    94  	SXCOFFTOC
    95  	SBSS
    96  	SNOPTRBSS
    97  	SLIBFUZZER_EXTRA_COUNTER
    98  	STLSBSS
    99  	SXREF
   100  	SMACHOSYMSTR
   101  	SMACHOSYMTAB
   102  	SMACHOINDIRECTPLT
   103  	SMACHOINDIRECTGOT
   104  	SFILEPATH
   105  	SCONST
   106  	SDYNIMPORT
   107  	SHOSTOBJ
   108  	SUNDEFEXT // Undefined symbol for resolution by external linker
   109  
   110  	// Sections for debugging information
   111  	SDWARFSECT
   112  	SDWARFINFO
   113  	SDWARFRANGE
   114  	SDWARFLOC
   115  	SDWARFLINES
   116  
   117  	// ABI aliases (these never appear in the output)
   118  	SABIALIAS
   119  )
   120  
   121  // AbiSymKindToSymKind maps values read from object files (which are
   122  // of type cmd/internal/objabi.SymKind) to values of type SymKind.
   123  var AbiSymKindToSymKind = [...]SymKind{
   124  	Sxxx,
   125  	STEXT,
   126  	SRODATA,
   127  	SNOPTRDATA,
   128  	SDATA,
   129  	SBSS,
   130  	SNOPTRBSS,
   131  	STLSBSS,
   132  	SDWARFINFO,
   133  	SDWARFRANGE,
   134  	SDWARFLOC,
   135  	SDWARFLINES,
   136  	SABIALIAS,
   137  	SLIBFUZZER_EXTRA_COUNTER,
   138  }
   139  
   140  // ReadOnly are the symbol kinds that form read-only sections. In some
   141  // cases, if they will require relocations, they are transformed into
   142  // rel-ro sections using relROMap.
   143  var ReadOnly = []SymKind{
   144  	STYPE,
   145  	SSTRING,
   146  	SGOSTRING,
   147  	SGOFUNC,
   148  	SGCBITS,
   149  	SRODATA,
   150  	SFUNCTAB,
   151  }
   152  
   153  // RelROMap describes the transformation of read-only symbols to rel-ro
   154  // symbols.
   155  var RelROMap = map[SymKind]SymKind{
   156  	STYPE:     STYPERELRO,
   157  	SSTRING:   SSTRINGRELRO,
   158  	SGOSTRING: SGOSTRINGRELRO,
   159  	SGOFUNC:   SGOFUNCRELRO,
   160  	SGCBITS:   SGCBITSRELRO,
   161  	SRODATA:   SRODATARELRO,
   162  	SFUNCTAB:  SFUNCTABRELRO,
   163  }
   164  
   165  // IsData returns true if the type is a data type.
   166  func (t SymKind) IsData() bool {
   167  	return t == SDATA || t == SNOPTRDATA || t == SBSS || t == SNOPTRBSS
   168  }