github.com/zebozhuang/go@v0.0.0-20200207033046-f8a98f6f5c5d/src/cmd/link/internal/ld/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 ld
    32  
    33  // A SymKind describes the kind of memory represented by a symbol.
    34  type SymKind int16
    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  	SELFSECT
    85  	SMACHO
    86  	SMACHOGOT
    87  	SWINDOWS
    88  	SELFGOT
    89  	SNOPTRDATA
    90  	SINITARR
    91  	SDATA
    92  	SBSS
    93  	SNOPTRBSS
    94  	STLSBSS
    95  	SXREF
    96  	SMACHOSYMSTR
    97  	SMACHOSYMTAB
    98  	SMACHOINDIRECTPLT
    99  	SMACHOINDIRECTGOT
   100  	SFILE
   101  	SFILEPATH
   102  	SCONST
   103  	SDYNIMPORT
   104  	SHOSTOBJ
   105  	SDWARFSECT
   106  	SDWARFINFO
   107  	SDWARFRANGE
   108  	SSUB       = SymKind(1 << 8)
   109  	SMASK      = SymKind(SSUB - 1)
   110  	SHIDDEN    = SymKind(1 << 9)
   111  	SCONTAINER = SymKind(1 << 10) // has a sub-symbol
   112  )
   113  
   114  // abiSymKindToSymKind maps values read from object files (which are
   115  // of type cmd/internal/objabi.SymKind) to values of type SymKind.
   116  var abiSymKindToSymKind = [...]SymKind{
   117  	Sxxx,
   118  	STEXT,
   119  	SRODATA,
   120  	SNOPTRDATA,
   121  	SDATA,
   122  	SBSS,
   123  	SNOPTRBSS,
   124  	STLSBSS,
   125  	SDWARFINFO,
   126  	SDWARFRANGE,
   127  }
   128  
   129  // readOnly are the symbol kinds that form read-only sections. In some
   130  // cases, if they will require relocations, they are transformed into
   131  // rel-ro sections using relROMap.
   132  var readOnly = []SymKind{
   133  	STYPE,
   134  	SSTRING,
   135  	SGOSTRING,
   136  	SGOFUNC,
   137  	SGCBITS,
   138  	SRODATA,
   139  	SFUNCTAB,
   140  }
   141  
   142  // relROMap describes the transformation of read-only symbols to rel-ro
   143  // symbols.
   144  var relROMap = map[SymKind]SymKind{
   145  	STYPE:     STYPERELRO,
   146  	SSTRING:   SSTRINGRELRO,
   147  	SGOSTRING: SGOSTRINGRELRO,
   148  	SGOFUNC:   SGOFUNCRELRO,
   149  	SGCBITS:   SGCBITSRELRO,
   150  	SRODATA:   SRODATARELRO,
   151  	SFUNCTAB:  SFUNCTABRELRO,
   152  }