Subversion Repositories or1k

@section Relocations

BFD maintains relocations in much the same way it maintains

symbols: they are left alone until required, then read in

en-mass and translated into an internal form.  A common

routine @code{bfd_perform_relocation} acts upon the

canonical form to do the fixup.

Relocations are maintained on a per section basis,

while symbols are maintained on a per BFD basis.

All that a back end has to do to fit the BFD interface is to create

a @code{struct reloc_cache_entry} for each relocation

in a particular section, and fill in the right bits of the structures.

@menu

* typedef arelent::

* howto manager::

@end menu

@node typedef arelent, howto manager, Relocations, Relocations

@subsection typedef arelent

This is the structure of a relocation entry:

@example

typedef enum bfd_reloc_status

@{

       /* No errors detected */

  bfd_reloc_ok,

       /* The relocation was performed, but there was an overflow. */

  bfd_reloc_overflow,

       /* The address to relocate was not within the section supplied. */

  bfd_reloc_outofrange,

       /* Used by special functions */

  bfd_reloc_continue,

       /* Unsupported relocation size requested. */

  bfd_reloc_notsupported,

       /* Unused */

  bfd_reloc_other,

       /* The symbol to relocate against was undefined. */

  bfd_reloc_undefined,

       /* The relocation was performed, but may not be ok - presently

          generated only when linking i960 coff files with i960 b.out

          symbols.  If this type is returned, the error_message argument

          to bfd_perform_relocation will be set.  */

  bfd_reloc_dangerous

 @}

 bfd_reloc_status_type;

typedef struct reloc_cache_entry

@{

       /* A pointer into the canonical table of pointers  */

  struct symbol_cache_entry **sym_ptr_ptr;

       /* offset in section */

  bfd_size_type address;

       /* addend for relocation value */

  bfd_vma addend;

       /* Pointer to how to perform the required relocation */

  reloc_howto_type *howto;

@} arelent;

@end example

@strong{Description}@*

Here is a description of each of the fields within an @code{arelent}:

@itemize @bullet

@item

@code{sym_ptr_ptr}

@end itemize

The symbol table pointer points to a pointer to the symbol

associated with the relocation request.  It is

the pointer into the table returned by the back end's

@code{get_symtab} action. @xref{Symbols}. The symbol is referenced

through a pointer to a pointer so that tools like the linker

can fix up all the symbols of the same name by modifying only

one pointer. The relocation routine looks in the symbol and

uses the base of the section the symbol is attached to and the

value of the symbol as the initial relocation offset. If the

symbol pointer is zero, then the section provided is looked up.

@itemize @bullet

@item

@code{address}

@end itemize

The @code{address} field gives the offset in bytes from the base of

the section data which owns the relocation record to the first

byte of relocatable information. The actual data relocated

will be relative to this point; for example, a relocation

type which modifies the bottom two bytes of a four byte word

would not touch the first byte pointed to in a big endian

world.

@itemize @bullet

@item

@code{addend}

@end itemize

The @code{addend} is a value provided by the back end to be added (!)

to the relocation offset. Its interpretation is dependent upon

the howto. For example, on the 68k the code:

@example

        char foo[];

        main()

                @{

                return foo[0x12345678];

                @}

@end example

Could be compiled into:

@example

        linkw fp,#-4

        moveb @@#12345678,d0

        extbl d0

        unlk fp

        rts

@end example

This could create a reloc pointing to @code{foo}, but leave the

offset in the data, something like:

@example

RELOCATION RECORDS FOR [.text]:

offset   type      value

00000006 32        _foo

00000000 4e56 fffc          ; linkw fp,#-4

00000004 1039 1234 5678     ; moveb @@#12345678,d0

0000000a 49c0               ; extbl d0

0000000c 4e5e               ; unlk fp

0000000e 4e75               ; rts

@end example

Using coff and an 88k, some instructions don't have enough

space in them to represent the full address range, and

pointers have to be loaded in two parts. So you'd get something like:

@example

        or.u     r13,r0,hi16(_foo+0x12345678)

        ld.b     r2,r13,lo16(_foo+0x12345678)

        jmp      r1

@end example

This should create two relocs, both pointing to @code{_foo}, and with

0x12340000 in their addend field. The data would consist of:

@example

RELOCATION RECORDS FOR [.text]:

offset   type      value

00000002 HVRT16    _foo+0x12340000

00000006 LVRT16    _foo+0x12340000

00000000 5da05678           ; or.u r13,r0,0x5678

00000004 1c4d5678           ; ld.b r2,r13,0x5678

00000008 f400c001           ; jmp r1

@end example

The relocation routine digs out the value from the data, adds

it to the addend to get the original offset, and then adds the

value of @code{_foo}. Note that all 32 bits have to be kept around

somewhere, to cope with carry from bit 15 to bit 16.

One further example is the sparc and the a.out format. The

sparc has a similar problem to the 88k, in that some

instructions don't have room for an entire offset, but on the

sparc the parts are created in odd sized lumps. The designers of

the a.out format chose to not use the data within the section

for storing part of the offset; all the offset is kept within

the reloc. Anything in the data should be ignored.

@example

        save %sp,-112,%sp

        sethi %hi(_foo+0x12345678),%g2

        ldsb [%g2+%lo(_foo+0x12345678)],%i0

        ret

        restore

@end example

Both relocs contain a pointer to @code{foo}, and the offsets

contain junk.

@example

RELOCATION RECORDS FOR [.text]:

offset   type      value

00000004 HI22      _foo+0x12345678

00000008 LO10      _foo+0x12345678

00000000 9de3bf90     ; save %sp,-112,%sp

00000004 05000000     ; sethi %hi(_foo+0),%g2

00000008 f048a000     ; ldsb [%g2+%lo(_foo+0)],%i0

0000000c 81c7e008     ; ret

00000010 81e80000     ; restore

@end example

@itemize @bullet

@item

@code{howto}

@end itemize

The @code{howto} field can be imagined as a

relocation instruction. It is a pointer to a structure which

contains information on what to do with all of the other

information in the reloc record and data section. A back end

would normally have a relocation instruction set and turn

relocations into pointers to the correct structure on input -

but it would be possible to create each howto field on demand.

@subsubsection @code{enum complain_overflow}

Indicates what sort of overflow checking should be done when

performing a relocation.

@example

enum complain_overflow

@{

       /* Do not complain on overflow. */

  complain_overflow_dont,

       /* Complain if the bitfield overflows, whether it is considered

          as signed or unsigned. */

  complain_overflow_bitfield,

       /* Complain if the value overflows when considered as signed

          number. */

  complain_overflow_signed,

       /* Complain if the value overflows when considered as an

          unsigned number. */

  complain_overflow_unsigned

@};

@end example

@subsubsection @code{reloc_howto_type}

The @code{reloc_howto_type} is a structure which contains all the

information that libbfd needs to know to tie up a back end's data.

@example

struct symbol_cache_entry;             /* Forward declaration */

struct reloc_howto_struct

@{

       /*  The type field has mainly a documentary use - the back end can

           do what it wants with it, though normally the back end's

           external idea of what a reloc number is stored

           in this field. For example, a PC relative word relocation

           in a coff environment has the type 023 - because that's

           what the outside world calls a R_PCRWORD reloc. */

  unsigned int type;

       /*  The value the final relocation is shifted right by. This drops

           unwanted data from the relocation.  */

  unsigned int rightshift;

       /*  The size of the item to be relocated.  This is *not* a

           power-of-two measure.  To get the number of bytes operated

           on by a type of relocation, use bfd_get_reloc_size.  */

  int size;

       /*  The number of bits in the item to be relocated.  This is used

           when doing overflow checking.  */

  unsigned int bitsize;

       /*  Notes that the relocation is relative to the location in the

           data section of the addend. The relocation function will

           subtract from the relocation value the address of the location

           being relocated. */

  boolean pc_relative;

       /*  The bit position of the reloc value in the destination.

           The relocated value is left shifted by this amount. */

  unsigned int bitpos;

       /* What type of overflow error should be checked for when

          relocating. */

  enum complain_overflow complain_on_overflow;

       /* If this field is non null, then the supplied function is

          called rather than the normal function. This allows really

          strange relocation methods to be accomodated (e.g., i960 callj

          instructions). */

  bfd_reloc_status_type (*special_function)

                                   PARAMS ((bfd *abfd,

                                            arelent *reloc_entry,

                                            struct symbol_cache_entry *symbol,

                                            PTR data,

                                            asection *input_section,

                                            bfd *output_bfd,

                                            char **error_message));

       /* The textual name of the relocation type. */

  char *name;

       /* Some formats record a relocation addend in the section contents

          rather than with the relocation.  For ELF formats this is the

          distinction between USE_REL and USE_RELA (though the code checks

          for USE_REL == 1/0).  The value of this field is TRUE if the

          addend is recorded with the section contents; when performing a

          partial link (ld -r) the section contents (the data) will be

          modified.  The value of this field is FALSE if addends are

          recorded with the relocation (in arelent.addend); when performing

          a partial link the relocation will be modified.

          All relocations for all ELF USE_RELA targets should set this field

          to FALSE (values of TRUE should be looked on with suspicion).

          However, the converse is not true: not all relocations of all ELF

          USE_REL targets set this field to TRUE.  Why this is so is peculiar

          to each particular target.  For relocs that aren't used in partial

          links (e.g. GOT stuff) it doesn't matter what this is set to.  */

  boolean partial_inplace;

       /* The src_mask selects which parts of the read in data

          are to be used in the relocation sum.  E.g., if this was an 8 bit

          byte of data which we read and relocated, this would be

          0x000000ff. When we have relocs which have an addend, such as

          sun4 extended relocs, the value in the offset part of a

          relocating field is garbage so we never use it. In this case

          the mask would be 0x00000000. */

  bfd_vma src_mask;

       /* The dst_mask selects which parts of the instruction are replaced

          into the instruction. In most cases src_mask == dst_mask,

          except in the above special case, where dst_mask would be

          0x000000ff, and src_mask would be 0x00000000.   */

  bfd_vma dst_mask;

       /* When some formats create PC relative instructions, they leave

          the value of the pc of the place being relocated in the offset

          slot of the instruction, so that a PC relative relocation can

          be made just by adding in an ordinary offset (e.g., sun3 a.out).

          Some formats leave the displacement part of an instruction

          empty (e.g., m88k bcs); this flag signals the fact.*/

  boolean pcrel_offset;

@};

@end example

@findex The HOWTO Macro

@subsubsection @code{The HOWTO Macro}

@strong{Description}@*

The HOWTO define is horrible and will go away.

@example

#define HOWTO(C, R,S,B, P, BI, O, SF, NAME, INPLACE, MASKSRC, MASKDST, PC) \

  @{(unsigned)C,R,S,B, P, BI, O,SF,NAME,INPLACE,MASKSRC,MASKDST,PC@}

@end example

@strong{Description}@*

And will be replaced with the totally magic way. But for the

moment, we are compatible, so do it this way.

@example

#define NEWHOWTO( FUNCTION, NAME,SIZE,REL,IN) HOWTO(0,0,SIZE,0,REL,0,complain_overflow_dont,FUNCTION, NAME,false,0,0,IN)

@end example

@strong{Description}@*

This is used to fill in an empty howto entry in an array.

@example

#define EMPTY_HOWTO(C) \

  HOWTO((C),0,0,0,false,0,complain_overflow_dont,NULL,NULL,false,0,0,false)

@end example

@strong{Description}@*

Helper routine to turn a symbol into a relocation value.

@example

#define HOWTO_PREPARE(relocation, symbol)      \

  @{                                            \

  if (symbol != (asymbol *)NULL) @{             \

    if (bfd_is_com_section (symbol->section)) @{ \

      relocation = 0;                          \

    @}                                          \

    else @{                                     \

      relocation = symbol->value;              \

    @}                                          \

  @}                                            \

@}

@end example

@findex bfd_get_reloc_size

@subsubsection @code{bfd_get_reloc_size}

@strong{Synopsis}

@example

unsigned int bfd_get_reloc_size (reloc_howto_type *);

@end example

@strong{Description}@*

For a reloc_howto_type that operates on a fixed number of bytes,

this returns the number of bytes operated on.

@findex arelent_chain

@subsubsection @code{arelent_chain}

@strong{Description}@*

How relocs are tied together in an @code{asection}:

@example

typedef struct relent_chain @{

  arelent relent;

  struct   relent_chain *next;

@} arelent_chain;

@end example

@findex bfd_check_overflow

@subsubsection @code{bfd_check_overflow}

@strong{Synopsis}

@example

bfd_reloc_status_type

bfd_check_overflow

   (enum complain_overflow how,

    unsigned int bitsize,

    unsigned int rightshift,

    unsigned int addrsize,

    bfd_vma relocation);

@end example

@strong{Description}@*

Perform overflow checking on @var{relocation} which has

@var{bitsize} significant bits and will be shifted right by

@var{rightshift} bits, on a machine with addresses containing

@var{addrsize} significant bits.  The result is either of

@code{bfd_reloc_ok} or @code{bfd_reloc_overflow}.

@findex bfd_perform_relocation

@subsubsection @code{bfd_perform_relocation}

@strong{Synopsis}

@example

bfd_reloc_status_type

bfd_perform_relocation

   (bfd *abfd,

    arelent *reloc_entry,

    PTR data,

    asection *input_section,

    bfd *output_bfd,

    char **error_message);

@end example

@strong{Description}@*

If @var{output_bfd} is supplied to this function, the

generated image will be relocatable; the relocations are

copied to the output file after they have been changed to

reflect the new state of the world. There are two ways of

reflecting the results of partial linkage in an output file:

by modifying the output data in place, and by modifying the

relocation record.  Some native formats (e.g., basic a.out and

basic coff) have no way of specifying an addend in the

relocation type, so the addend has to go in the output data.

This is no big deal since in these formats the output data

slot will always be big enough for the addend. Complex reloc

types with addends were invented to solve just this problem.

The @var{error_message} argument is set to an error message if

this return @code{bfd_reloc_dangerous}.

@findex bfd_install_relocation

@subsubsection @code{bfd_install_relocation}

@strong{Synopsis}

@example

bfd_reloc_status_type

bfd_install_relocation

   (bfd *abfd,

    arelent *reloc_entry,

    PTR data, bfd_vma data_start,

    asection *input_section,

    char **error_message);

@end example

@strong{Description}@*

This looks remarkably like @code{bfd_perform_relocation}, except it

does not expect that the section contents have been filled in.

I.e., it's suitable for use when creating, rather than applying

a relocation.

For now, this function should be considered reserved for the

assembler.

@node howto manager,  , typedef arelent, Relocations

@section The howto manager

When an application wants to create a relocation, but doesn't

know what the target machine might call it, it can find out by

using this bit of code.

@findex bfd_reloc_code_type

@subsubsection @code{bfd_reloc_code_type}

@strong{Description}@*

The insides of a reloc code.  The idea is that, eventually, there

will be one enumerator for every type of relocation we ever do.

Pass one of these values to @code{bfd_reloc_type_lookup}, and it'll

return a howto pointer.

This does mean that the application must determine the correct

enumerator value; you can't get a howto pointer from a random set

of attributes.

Here are the possible values for @code{enum bfd_reloc_code_real}:

@deffn {} BFD_RELOC_64

@deffnx {} BFD_RELOC_32

@deffnx {} BFD_RELOC_26

@deffnx {} BFD_RELOC_24

@deffnx {} BFD_RELOC_16

@deffnx {} BFD_RELOC_14

@deffnx {} BFD_RELOC_8

Basic absolute relocations of N bits.

@end deffn

@deffn {} BFD_RELOC_64_PCREL

@deffnx {} BFD_RELOC_32_PCREL

@deffnx {} BFD_RELOC_24_PCREL

@deffnx {} BFD_RELOC_16_PCREL

@deffnx {} BFD_RELOC_12_PCREL

@deffnx {} BFD_RELOC_8_PCREL

PC-relative relocations.  Sometimes these are relative to the address

of the relocation itself; sometimes they are relative to the start of

the section containing the relocation.  It depends on the specific target.

The 24-bit relocation is used in some Intel 960 configurations.

@end deffn

@deffn {} BFD_RELOC_32_GOT_PCREL

@deffnx {} BFD_RELOC_16_GOT_PCREL

@deffnx {} BFD_RELOC_8_GOT_PCREL

@deffnx {} BFD_RELOC_32_GOTOFF

@deffnx {} BFD_RELOC_16_GOTOFF

@deffnx {} BFD_RELOC_LO16_GOTOFF

@deffnx {} BFD_RELOC_HI16_GOTOFF

@deffnx {} BFD_RELOC_HI16_S_GOTOFF

@deffnx {} BFD_RELOC_8_GOTOFF

@deffnx {} BFD_RELOC_32_PLT_PCREL

@deffnx {} BFD_RELOC_24_PLT_PCREL

@deffnx {} BFD_RELOC_16_PLT_PCREL

@deffnx {} BFD_RELOC_8_PLT_PCREL

@deffnx {} BFD_RELOC_32_PLTOFF

@deffnx {} BFD_RELOC_16_PLTOFF

@deffnx {} BFD_RELOC_LO16_PLTOFF

@deffnx {} BFD_RELOC_HI16_PLTOFF

@deffnx {} BFD_RELOC_HI16_S_PLTOFF

@deffnx {} BFD_RELOC_8_PLTOFF

For ELF.

@end deffn

@deffn {} BFD_RELOC_68K_GLOB_DAT

@deffnx {} BFD_RELOC_68K_JMP_SLOT

@deffnx {} BFD_RELOC_68K_RELATIVE

Relocations used by 68K ELF.

@end deffn

@deffn {} BFD_RELOC_32_BASEREL

@deffnx {} BFD_RELOC_16_BASEREL

@deffnx {} BFD_RELOC_LO16_BASEREL

@deffnx {} BFD_RELOC_HI16_BASEREL

@deffnx {} BFD_RELOC_HI16_S_BASEREL

@deffnx {} BFD_RELOC_8_BASEREL

@deffnx {} BFD_RELOC_RVA

Linkage-table relative.

@end deffn

@deffn {} BFD_RELOC_8_FFnn

Absolute 8-bit relocation, but used to form an address like 0xFFnn.

@end deffn

@deffn {} BFD_RELOC_32_PCREL_S2

@deffnx {} BFD_RELOC_16_PCREL_S2

@deffnx {} BFD_RELOC_23_PCREL_S2

These PC-relative relocations are stored as word displacements --

i.e., byte displacements shifted right two bits.  The 30-bit word

displacement (<<32_PCREL_S2>> -- 32 bits, shifted 2) is used on the

SPARC.  (SPARC tools generally refer to this as <<WDISP30>>.)  The

signed 16-bit displacement is used on the MIPS, and the 23-bit

displacement is used on the Alpha.

@end deffn

@deffn {} BFD_RELOC_HI22

@deffnx {} BFD_RELOC_LO10

High 22 bits and low 10 bits of 32-bit value, placed into lower bits of

the target word.  These are used on the SPARC.

@end deffn

@deffn {} BFD_RELOC_GPREL16

@deffnx {} BFD_RELOC_GPREL32

For systems that allocate a Global Pointer register, these are

displacements off that register.  These relocation types are

handled specially, because the value the register will have is

decided relatively late.

@end deffn

@deffn {} BFD_RELOC_I960_CALLJ

Reloc types used for i960/b.out.

@end deffn

@deffn {} BFD_RELOC_NONE

@deffnx {} BFD_RELOC_SPARC_WDISP22

@deffnx {} BFD_RELOC_SPARC22

@deffnx {} BFD_RELOC_SPARC13

@deffnx {} BFD_RELOC_SPARC_GOT10

@deffnx {} BFD_RELOC_SPARC_GOT13

@deffnx {} BFD_RELOC_SPARC_GOT22

@deffnx {} BFD_RELOC_SPARC_PC10

@deffnx {} BFD_RELOC_SPARC_PC22

@deffnx {} BFD_RELOC_SPARC_WPLT30

@deffnx {} BFD_RELOC_SPARC_COPY

@deffnx {} BFD_RELOC_SPARC_GLOB_DAT

@deffnx {} BFD_RELOC_SPARC_JMP_SLOT

@deffnx {} BFD_RELOC_SPARC_RELATIVE

@deffnx {} BFD_RELOC_SPARC_UA32

SPARC ELF relocations.  There is probably some overlap with other

relocation types already defined.

@end deffn

@deffn {} BFD_RELOC_SPARC_BASE13

@deffnx {} BFD_RELOC_SPARC_BASE22

I think these are specific to SPARC a.out (e.g., Sun 4).

@end deffn

@deffn {} BFD_RELOC_SPARC_64

@deffnx {} BFD_RELOC_SPARC_10

@deffnx {} BFD_RELOC_SPARC_11

@deffnx {} BFD_RELOC_SPARC_OLO10

@deffnx {} BFD_RELOC_SPARC_HH22

@deffnx {} BFD_RELOC_SPARC_HM10

@deffnx {} BFD_RELOC_SPARC_LM22

@deffnx {} BFD_RELOC_SPARC_PC_HH22

@deffnx {} BFD_RELOC_SPARC_PC_HM10

@deffnx {} BFD_RELOC_SPARC_PC_LM22

@deffnx {} BFD_RELOC_SPARC_WDISP16

@deffnx {} BFD_RELOC_SPARC_WDISP19

@deffnx {} BFD_RELOC_SPARC_7

@deffnx {} BFD_RELOC_SPARC_6

@deffnx {} BFD_RELOC_SPARC_5

@deffnx {} BFD_RELOC_SPARC_DISP64

@deffnx {} BFD_RELOC_SPARC_PLT64

@deffnx {} BFD_RELOC_SPARC_HIX22

@deffnx {} BFD_RELOC_SPARC_LOX10

@deffnx {} BFD_RELOC_SPARC_H44

@deffnx {} BFD_RELOC_SPARC_M44

@deffnx {} BFD_RELOC_SPARC_L44

@deffnx {} BFD_RELOC_SPARC_REGISTER

SPARC64 relocations

@end deffn

@deffn {} BFD_RELOC_SPARC_REV32

SPARC little endian relocation

@end deffn

@deffn {} BFD_RELOC_ALPHA_GPDISP_HI16

Alpha ECOFF and ELF relocations.  Some of these treat the symbol or

"addend" in some special way.

For GPDISP_HI16 ("gpdisp") relocations, the symbol is ignored when

writing; when reading, it will be the absolute section symbol.  The

addend is the displacement in bytes of the "lda" instruction from

the "ldah" instruction (which is at the address of this reloc).

@end deffn

@deffn {} BFD_RELOC_ALPHA_GPDISP_LO16

For GPDISP_LO16 ("ignore") relocations, the symbol is handled as

with GPDISP_HI16 relocs.  The addend is ignored when writing the

relocations out, and is filled in with the file's GP value on

reading, for convenience.

@end deffn

@deffn {} BFD_RELOC_ALPHA_GPDISP

The ELF GPDISP relocation is exactly the same as the GPDISP_HI16

relocation except that there is no accompanying GPDISP_LO16

relocation.

@end deffn

@deffn {} BFD_RELOC_ALPHA_LITERAL

@deffnx {} BFD_RELOC_ALPHA_ELF_LITERAL

@deffnx {} BFD_RELOC_ALPHA_LITUSE

The Alpha LITERAL/LITUSE relocs are produced by a symbol reference;

the assembler turns it into a LDQ instruction to load the address of

the symbol, and then fills in a register in the real instruction.

The LITERAL reloc, at the LDQ instruction, refers to the .lita

section symbol.  The addend is ignored when writing, but is filled

in with the file's GP value on reading, for convenience, as with the

GPDISP_LO16 reloc.

The ELF_LITERAL reloc is somewhere between 16_GOTOFF and GPDISP_LO16.

It should refer to the symbol to be referenced, as with 16_GOTOFF,

but it generates output not based on the position within the .got

section, but relative to the GP value chosen for the file during the

final link stage.

The LITUSE reloc, on the instruction using the loaded address, gives

information to the linker that it might be able to use to optimize

away some literal section references.  The symbol is ignored (read

as the absolute section symbol), and the "addend" indicates the type

of instruction using the register:

1 - "memory" fmt insn

2 - byte-manipulation (byte offset reg)

3 - jsr (target of branch)

The GNU linker currently doesn't do any of this optimizing.

@end deffn

@deffn {} BFD_RELOC_ALPHA_USER_LITERAL

@deffnx {} BFD_RELOC_ALPHA_USER_LITUSE_BASE

@deffnx {} BFD_RELOC_ALPHA_USER_LITUSE_BYTOFF

@deffnx {} BFD_RELOC_ALPHA_USER_LITUSE_JSR

@deffnx {} BFD_RELOC_ALPHA_USER_GPDISP

@deffnx {} BFD_RELOC_ALPHA_USER_GPRELHIGH

@deffnx {} BFD_RELOC_ALPHA_USER_GPRELLOW

The BFD_RELOC_ALPHA_USER_* relocations are used by the assembler to

process the explicit !<reloc>!sequence relocations, and are mapped

into the normal relocations at the end of processing.

@end deffn

@deffn {} BFD_RELOC_ALPHA_HINT

The HINT relocation indicates a value that should be filled into the

"hint" field of a jmp/jsr/ret instruction, for possible branch-

prediction logic which may be provided on some processors.

@end deffn

@deffn {} BFD_RELOC_ALPHA_LINKAGE

The LINKAGE relocation outputs a linkage pair in the object file,

which is filled by the linker.

@end deffn

@deffn {} BFD_RELOC_ALPHA_CODEADDR

The CODEADDR relocation outputs a STO_CA in the object file,

which is filled by the linker.

@end deffn

@deffn {} BFD_RELOC_MIPS_JMP

Bits 27..2 of the relocation address shifted right 2 bits;

simple reloc otherwise.

@end deffn

@deffn {} BFD_RELOC_MIPS16_JMP

The MIPS16 jump instruction.

@end deffn

@deffn {} BFD_RELOC_MIPS16_GPREL

MIPS16 GP relative reloc.

@end deffn

@deffn {} BFD_RELOC_HI16

High 16 bits of 32-bit value; simple reloc.

@end deffn

@deffn {} BFD_RELOC_HI16_S

High 16 bits of 32-bit value but the low 16 bits will be sign

extended and added to form the final result.  If the low 16

bits form a negative number, we need to add one to the high value

to compensate for the borrow when the low bits are added.

@end deffn

@deffn {} BFD_RELOC_LO16

Low 16 bits.

@end deffn

@deffn {} BFD_RELOC_PCREL_HI16_S

Like BFD_RELOC_HI16_S, but PC relative.

@end deffn

@deffn {} BFD_RELOC_PCREL_LO16

Like BFD_RELOC_LO16, but PC relative.

@end deffn

@deffn {} BFD_RELOC_MIPS_GPREL

Relocation relative to the global pointer.

@end deffn

@deffn {} BFD_RELOC_MIPS_LITERAL

Relocation against a MIPS literal section.

@end deffn

@deffn {} BFD_RELOC_MIPS_GOT16

@deffnx {} BFD_RELOC_MIPS_CALL16

@deffnx {} BFD_RELOC_MIPS_GPREL32

@deffnx {} BFD_RELOC_MIPS_GOT_HI16

@deffnx {} BFD_RELOC_MIPS_GOT_LO16

@deffnx {} BFD_RELOC_MIPS_CALL_HI16

@deffnx {} BFD_RELOC_MIPS_CALL_LO16

@deffnx {} BFD_RELOC_MIPS_SUB

@deffnx {} BFD_RELOC_MIPS_GOT_PAGE

@deffnx {} BFD_RELOC_MIPS_GOT_OFST

@deffnx {} BFD_RELOC_MIPS_GOT_DISP

MIPS ELF relocations.

@end deffn

@deffn {} BFD_RELOC_386_GOT32

@deffnx {} BFD_RELOC_386_PLT32

@deffnx {} BFD_RELOC_386_COPY

@deffnx {} BFD_RELOC_386_GLOB_DAT

@deffnx {} BFD_RELOC_386_JUMP_SLOT

@deffnx {} BFD_RELOC_386_RELATIVE

@deffnx {} BFD_RELOC_386_GOTOFF

@deffnx {} BFD_RELOC_386_GOTPC

i386/elf relocations

@end deffn

@deffn {} BFD_RELOC_NS32K_IMM_8

@deffnx {} BFD_RELOC_NS32K_IMM_16

@deffnx {} BFD_RELOC_NS32K_IMM_32

@deffnx {} BFD_RELOC_NS32K_IMM_8_PCREL

@deffnx {} BFD_RELOC_NS32K_IMM_16_PCREL

@deffnx {} BFD_RELOC_NS32K_IMM_32_PCREL

@deffnx {} BFD_RELOC_NS32K_DISP_8

@deffnx {} BFD_RELOC_NS32K_DISP_16

@deffnx {} BFD_RELOC_NS32K_DISP_32

@deffnx {} BFD_RELOC_NS32K_DISP_8_PCREL

@deffnx {} BFD_RELOC_NS32K_DISP_16_PCREL

@deffnx {} BFD_RELOC_NS32K_DISP_32_PCREL

ns32k relocations

@end deffn

@deffn {} BFD_RELOC_PJ_CODE_HI16

@deffnx {} BFD_RELOC_PJ_CODE_LO16

@deffnx {} BFD_RELOC_PJ_CODE_DIR16

@deffnx {} BFD_RELOC_PJ_CODE_DIR32

@deffnx {} BFD_RELOC_PJ_CODE_REL16

@deffnx {} BFD_RELOC_PJ_CODE_REL32

Picojava relocs.  Not all of these appear in object files.

@end deffn

@deffn {} BFD_RELOC_PPC_B26

@deffnx {} BFD_RELOC_PPC_BA26

@deffnx {} BFD_RELOC_PPC_TOC16

@deffnx {} BFD_RELOC_PPC_B16

@deffnx {} BFD_RELOC_PPC_B16_BRTAKEN

@deffnx {} BFD_RELOC_PPC_B16_BRNTAKEN

@deffnx {} BFD_RELOC_PPC_BA16

@deffnx {} BFD_RELOC_PPC_BA16_BRTAKEN

@deffnx {} BFD_RELOC_PPC_BA16_BRNTAKEN

@deffnx {} BFD_RELOC_PPC_COPY

@deffnx {} BFD_RELOC_PPC_GLOB_DAT

@deffnx {} BFD_RELOC_PPC_JMP_SLOT

@deffnx {} BFD_RELOC_PPC_RELATIVE

@deffnx {} BFD_RELOC_PPC_LOCAL24PC

@deffnx {} BFD_RELOC_PPC_EMB_NADDR32

@deffnx {} BFD_RELOC_PPC_EMB_NADDR16

@deffnx {} BFD_RELOC_PPC_EMB_NADDR16_LO

@deffnx {} BFD_RELOC_PPC_EMB_NADDR16_HI

@deffnx {} BFD_RELOC_PPC_EMB_NADDR16_HA

@deffnx {} BFD_RELOC_PPC_EMB_SDAI16

@deffnx {} BFD_RELOC_PPC_EMB_SDA2I16

@deffnx {} BFD_RELOC_PPC_EMB_SDA2REL

@deffnx {} BFD_RELOC_PPC_EMB_SDA21

@deffnx {} BFD_RELOC_PPC_EMB_MRKREF

@deffnx {} BFD_RELOC_PPC_EMB_RELSEC16

@deffnx {} BFD_RELOC_PPC_EMB_RELST_LO

@deffnx {} BFD_RELOC_PPC_EMB_RELST_HI

@deffnx {} BFD_RELOC_PPC_EMB_RELST_HA

@deffnx {} BFD_RELOC_PPC_EMB_BIT_FLD

@deffnx {} BFD_RELOC_PPC_EMB_RELSDA

Power(rs6000) and PowerPC relocations.

@end deffn

@deffn {} BFD_RELOC_I370_D12

IBM 370/390 relocations

@end deffn

@deffn {} BFD_RELOC_CTOR

The type of reloc used to build a contructor table - at the moment

probably a 32 bit wide absolute relocation, but the target can choose.

It generally does map to one of the other relocation types.

@end deffn

@deffn {} BFD_RELOC_ARM_PCREL_BRANCH

ARM 26 bit pc-relative branch.  The lowest two bits must be zero and are

not stored in the instruction.

@end deffn

@deffn {} BFD_RELOC_ARM_PCREL_BLX

ARM 26 bit pc-relative branch.  The lowest bit must be zero and is

not stored in the instruction.  The 2nd lowest bit comes from a 1 bit

field in the instruction.

@end deffn

@deffn {} BFD_RELOC_THUMB_PCREL_BLX

Thumb 22 bit pc-relative branch.  The lowest bit must be zero and is

not stored in the instruction.  The 2nd lowest bit comes from a 1 bit

field in the instruction.

@end deffn

@deffn {} BFD_RELOC_ARM_IMMEDIATE

@deffnx {} BFD_RELOC_ARM_ADRL_IMMEDIATE

@deffnx {} BFD_RELOC_ARM_OFFSET_IMM

@deffnx {} BFD_RELOC_ARM_SHIFT_IMM

@deffnx {} BFD_RELOC_ARM_SWI

@deffnx {} BFD_RELOC_ARM_MULTI

@deffnx {} BFD_RELOC_ARM_CP_OFF_IMM

@deffnx {} BFD_RELOC_ARM_ADR_IMM

@deffnx {} BFD_RELOC_ARM_LDR_IMM

@deffnx {} BFD_RELOC_ARM_LITERAL

@deffnx {} BFD_RELOC_ARM_IN_POOL

@deffnx {} BFD_RELOC_ARM_OFFSET_IMM8

@deffnx {} BFD_RELOC_ARM_HWLITERAL

@deffnx {} BFD_RELOC_ARM_THUMB_ADD

@deffnx {} BFD_RELOC_ARM_THUMB_IMM

@deffnx {} BFD_RELOC_ARM_THUMB_SHIFT

@deffnx {} BFD_RELOC_ARM_THUMB_OFFSET

@deffnx {} BFD_RELOC_ARM_GOT12

@deffnx {} BFD_RELOC_ARM_GOT32

@deffnx {} BFD_RELOC_ARM_JUMP_SLOT

@deffnx {} BFD_RELOC_ARM_COPY

@deffnx {} BFD_RELOC_ARM_GLOB_DAT

@deffnx {} BFD_RELOC_ARM_PLT32

@deffnx {} BFD_RELOC_ARM_RELATIVE

@deffnx {} BFD_RELOC_ARM_GOTOFF

@deffnx {} BFD_RELOC_ARM_GOTPC

These relocs are only used within the ARM assembler.  They are not

(at present) written to any object files.

@end deffn

@deffn {} BFD_RELOC_SH_PCDISP8BY2

@deffnx {} BFD_RELOC_SH_PCDISP12BY2

@deffnx {} BFD_RELOC_SH_IMM4

@deffnx {} BFD_RELOC_SH_IMM4BY2

@deffnx {} BFD_RELOC_SH_IMM4BY4

@deffnx {} BFD_RELOC_SH_IMM8

@deffnx {} BFD_RELOC_SH_IMM8BY2

@deffnx {} BFD_RELOC_SH_IMM8BY4

@deffnx {} BFD_RELOC_SH_PCRELIMM8BY2

@deffnx {} BFD_RELOC_SH_PCRELIMM8BY4

@deffnx {} BFD_RELOC_SH_SWITCH16

@deffnx {} BFD_RELOC_SH_SWITCH32

@deffnx {} BFD_RELOC_SH_USES

@deffnx {} BFD_RELOC_SH_COUNT

@deffnx {} BFD_RELOC_SH_ALIGN

@deffnx {} BFD_RELOC_SH_CODE

@deffnx {} BFD_RELOC_SH_DATA

@deffnx {} BFD_RELOC_SH_LABEL

@deffnx {} BFD_RELOC_SH_LOOP_START

@deffnx {} BFD_RELOC_SH_LOOP_END

Hitachi SH relocs.  Not all of these appear in object files.

@end deffn

@deffn {} BFD_RELOC_THUMB_PCREL_BRANCH9

@deffnx {} BFD_RELOC_THUMB_PCREL_BRANCH12

@deffnx {} BFD_RELOC_THUMB_PCREL_BRANCH23

Thumb 23-, 12- and 9-bit pc-relative branches.  The lowest bit must

be zero and is not stored in the instruction.

@end deffn

@deffn {} BFD_RELOC_ARC_B22_PCREL

Argonaut RISC Core (ARC) relocs.

ARC 22 bit pc-relative branch.  The lowest two bits must be zero and are

not stored in the instruction.  The high 20 bits are installed in bits 26

through 7 of the instruction.

@end deffn

@deffn {} BFD_RELOC_ARC_B26

ARC 26 bit absolute branch.  The lowest two bits must be zero and are not

stored in the instruction.  The high 24 bits are installed in bits 23

through 0.

@end deffn

@deffn {} BFD_RELOC_D10V_10_PCREL_R

Mitsubishi D10V relocs.

This is a 10-bit reloc with the right 2 bits

assumed to be 0.

@end deffn

@deffn {} BFD_RELOC_D10V_10_PCREL_L

Mitsubishi D10V relocs.

This is a 10-bit reloc with the right 2 bits

assumed to be 0.  This is the same as the previous reloc

except it is in the left container, i.e.,

shifted left 15 bits.

@end deffn

@deffn {} BFD_RELOC_D10V_18

This is an 18-bit reloc with the right 2 bits

assumed to be 0.

@end deffn

@deffn {} BFD_RELOC_D10V_18_PCREL

This is an 18-bit reloc with the right 2 bits

assumed to be 0.

@end deffn

@deffn {} BFD_RELOC_D30V_6

Mitsubishi D30V relocs.

This is a 6-bit absolute reloc.

@end deffn

@deffn {} BFD_RELOC_D30V_9_PCREL

This is a 6-bit pc-relative reloc with

the right 3 bits assumed to be 0.

@end deffn

@deffn {} BFD_RELOC_D30V_9_PCREL_R

This is a 6-bit pc-relative reloc with