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reloc(5) [ultrix man page]

reloc(5)							File Formats Manual							  reloc(5)

       reloc - relocation information for a MIPS object file

       #include <reloc.h>

       Object  files  have one relocation entry for each relocatable reference in the text or data.  If relocation information is present, it will
       be in the following format:

       struct	reloc
	  long	    r_vaddr ;	       /* (virtual) address of reference */
	  long	    r_symndx ;	       /* index into symbol table */
	  ushort    r_type ;	       /* relocation type */
	  unsigned  r_symndx:24,       /* index into symbol table */
		    r_type:4,	       /* relocation type */
		    r_extern:1;        /* if 1 symndx is an index into the
					  external symbol table, else symndx
					  is a section # */
       } ;

       /* Relocation types */

       #define	R_ABS	    0
       #define	R_REFHALF   1
       #define	R_REFWORD   2
       #define	R_JMPADDR   3
       #define	R_REFHI     4
       #define	R_REFLO     5
       #define	R_GPREL     6
       #define	R_LITERAL   7

       /* Section numbers */

       #define	R_SN_NULL   0
       #define	R_SN_TEXT   1
       #define	R_SN_RDATA  2
       #define	R_SN_DATA   3
       #define	R_SN_SDATA  4
       #define	R_SN_SBSS   5
       #define	R_SN_BSS    6
       #define	R_SN_INIT   7
       #define	R_SN_LIT8   8
       #define	R_SN_LIT4   9

       The link editor reads each input section and performs relocation.  The relocation entries direct how references found within the input sec-
       tion are treated.

       If  is zero, it is a local relocation entry and then is a section number (R_SN_*).  For these entries, the starting address for the section
       referenced by the section number is used in place of an external symbol table entry's value.  The assembler and	loader	always	use  local
       relocation entries if the item to be relocated is defined in the object file.

       For  every  external  relocation (except R_ABS) a signed constant is added to the symbol's virtual address that the relocation entry refers
       to.  This constant is assembled at the address being relocated.

       R_ABS	      The reference is absolute and no relocation is necessary.  The entry will be ignored.

       R_REFHALF      A 16-bit reference to the symbol's virtual address.

       R_REFWORD      A 32-bit reference to the symbol's virtual address.

       R_JMPADDR      A 26-bit jump instruction reference to the symbol's virtual address.

       R_REFHI	      A reference to the high 16 bits of the symbol's virtual address.	The  next  relocation  entry  must  be	the  corresponding
		      R_REFLO entry, so the proper value of the constant to be added to the symbol's virtual address can be reconstructed.

       R_REFLO	      A reference to low 16 bits to the symbol's virtual address.

       R_GPREL	      A 16-bit offset to the symbol's virtual address from the global pointer register.

       R_LITERAL      A 16-bit offset to the literal's virtual address from the global pointer register.

       Relocation  entries  are generated automatically by the assembler and automatically used by the link editor.  Link editor options exist for
       both preserving and removing the relocation entries from object files.

       The number of relocation entries for a section is found in the field of the section header.  This field is a C language short and can over-
       flow  with  large objects.  If this field overflows, the section header field has the S_NRELOC_OVFL bit set.  In this case, the true number
       of relocation entries is found in the field of the first relocation entry for that section.  That relocation entry has a type of R_ABS,	so
       it is ignored when the relocation takes place.

See Also
       as(1), ld(1), a.out(5), syms(5), scnhdr(5)

								       RISC								  reloc(5)

Check Out this Related Man Page

DWARF_ADD_ARANGE(3)					   BSD Library Functions Manual 				       DWARF_ADD_ARANGE(3)

dwarf_add_arange, dwarf_add_arange_b -- add address range information to a DWARF producer instance LIBRARY
DWARF Access Library (libdwarf, -ldwarf) SYNOPSIS
#include <libdwarf.h> Dwarf_Unsigned dwarf_add_arange(Dwarf_P_Debug dbg, Dwarf_Addr start, Dwarf_Unsigned length, Dwarf_Signed symbol_index, Dwarf_Error *err); Dwarf_Unsigned dwarf_add_arange_b(Dwarf_P_Debug dbg, Dwarf_Addr start, Dwarf_Unsigned length, Dwarf_Unsigned symbol_index, Dwarf_Unsigned end_symbol_index, Dwarf_Addr offset_from_end_symbol, Dwarf_Error *err); DESCRIPTION
Function dwarf_add_arange_b() adds an address range entry to a producer instance. Argument dbg should reference a DWARF producer instance allocated using dwarf_producer_init(3) or dwarf_producer_init_b(3). Argument start specifies the relocatable start address of the address range. Argument length specifies the length of the address range. Argument symbol_index specifies the ELF symbol index of the first symbol to be used for relocation. Argument end_symbol_index specifies the ELF symbol index of the second symbol to be used for relocation. o If argument end_symbol_index is not 0, the DW_DLC_SYMBOLIC_RELOCATIONS flag should have been set on the DWARF producer instance. The address value specified by argument start will be treated as an offset value from the first symbol, and the argument offset_from_end_symbol should hold an offset value from the second symbol. Application code can retrieve the relocation entries for the symbol pair by calling function dwarf_get_relocation_info(3). The relocation entry for the first symbol will have type dwarf_drt_first_of_length_pair and the relocation entry for the second symbol will have type dwarf_drt_second_of_length_pair. o If argument end_symbol_index is 0, argument offset_from_end_symbol will be ignored and only one symbol is used for relocation. If argument err is not NULL, it will be used to store error information in case of an error. Function dwarf_add_arange() is deprecated. It is similar to function dwarf_add_arange_b() except that it cannot handle all possible symbol index values and supports only one relocation symbol. RETURN VALUES
On success, these functions return a non-zero value. In case of an error, these functions return 0 and set the argument err. ERRORS
These functions can fail with: [DW_DLE_ARGUMENT] Argument dbg was NULL. [DW_DLE_ARGUMENT] Argument end_symbol_index was non-zero, but the flag DW_DLC_SYMBOLIC_RELOCATIONS was not set on the producer instance. [DW_DLE_MEMORY] An out of memory condition was encountered during the execution of the function. SEE ALSO
dwarf(3), dwarf_get_relocation_info(3), dwarf_producer_init(3), dwarf_producer_init_b(3) BSD
September 18, 2011 BSD
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