xref: /netbsd-src/external/gpl3/gdb/dist/include/elf/reloc-macros.h (revision 02f41505626a9ceb584d30d0789203495760ac88)

/* Generic relocation support for BFD.
   Copyright (C) 1998-2024 Free Software Foundation, Inc.

   This file is part of BFD, the Binary File Descriptor library.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 3 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software Foundation,
   Inc., 51 Franklin Street - Fifth Floor, Boston, MA 02110-1301, USA.  */

/* These macros are used by the various *.h target specific header
   files to either generate an enum containing all the known relocations
   for that target, or if RELOC_MACROS_GEN_FUNC is defined, a recognition
   function is generated instead.  (This is used by binutils/readelf.c)

   Given a header file like this:

   	START_RELOC_NUMBERS (foo)
   	    RELOC_NUMBER (R_foo_NONE,    0)
   	    RELOC_NUMBER (R_foo_32,      1)
   	    EMPTY_RELOC  (R_foo_good)
   	    FAKE_RELOC   (R_foo_illegal, 9)
   	END_RELOC_NUMBERS (R_foo_count)

   Then the following will be produced by default (ie if
   RELOC_MACROS_GEN_FUNC is *not* defined).

   	enum foo
	{
   	  R_foo_NONE = 0,
   	  R_foo_32 = 1,
	  R_foo_good,
   	  R_foo_illegal = 9,
   	  R_foo_count
   	};

   Note: The value of the symbol defined in the END_RELOC_NUMBERS
   macro (R_foo_count in the case of the example above) will be
   set to the value of the whichever *_RELOC macro precedes it plus
   one.  Therefore if you intend to use the symbol as a sentinel for
   the highest valid macro value you should make sure that the
   preceding *_RELOC macro is the highest valid number.  ie a
   declaration like this:

   	START_RELOC_NUMBERS (foo)
   	    RELOC_NUMBER (R_foo_NONE,    0)
   	    RELOC_NUMBER (R_foo_32,      1)
   	    FAKE_RELOC   (R_foo_illegal, 9)
   	    FAKE_RELOC   (R_foo_synonym, 0)
   	END_RELOC_NUMBERS (R_foo_count)

   will result in R_foo_count having a value of 1 (R_foo_synonym + 1)
   rather than 10 or 2 as might be expected.

   Alternatively you can assign a value to END_RELOC_NUMBERS symbol
   explicitly, like this:

   	START_RELOC_NUMBERS (foo)
   	    RELOC_NUMBER (R_foo_NONE,    0)
   	    RELOC_NUMBER (R_foo_32,      1)
   	    FAKE_RELOC   (R_foo_illegal, 9)
   	    FAKE_RELOC   (R_foo_synonym, 0)
   	END_RELOC_NUMBERS (R_foo_count = 2)

   If RELOC_MACROS_GEN_FUNC *is* defined, then instead the
   following function will be generated:

   	static const char *foo (unsigned long rtype);
   	static const char *
   	foo (unsigned long rtype)
   	{
   	   switch (rtype)
   	   {
   	   case 0: return "R_foo_NONE";
   	   case 1: return "R_foo_32";
   	   default: return NULL;
   	   }
   	}
   */

#ifndef _RELOC_MACROS_H
#define _RELOC_MACROS_H

#ifdef RELOC_MACROS_GEN_FUNC

/* This function takes the relocation number and returns the
   string version name of the name of that relocation.  If
   the relocation is not recognised, NULL is returned.  */

#define START_RELOC_NUMBERS(name)   				\
static const char *name (unsigned long rtype);			\
static const char *						\
name (unsigned long rtype)					\
{								\
  switch (rtype)						\
    {

#define RELOC_NUMBER(name, number) \
    case number: return #name;

#define FAKE_RELOC(name, number)
#define EMPTY_RELOC(name)

#define END_RELOC_NUMBERS(name)	\
    default: return NULL;	\
    }				\
}


#else /* Default to generating enum.  */

#define START_RELOC_NUMBERS(name)   enum name {
#define RELOC_NUMBER(name, number)  name = number,
#define FAKE_RELOC(name, number)    name = number,
#define EMPTY_RELOC(name)           name,
#define END_RELOC_NUMBERS(name)     name };

#endif

#endif /* _RELOC_MACROS_H */