* $Id: ld.h,v 1.8 1994/01/28 20:56:24 pk Exp $
* This code is derived from software copyrighted by the Free Software
* Modified 1991 by Donn Seeley at UUNET Technologies, Inc.
#define min(a,b) ((a) < (b) ? (a) : (b))
/* If compiled with GNU C, use the built-in alloca */
#if defined(__GNUC__) || defined(sparc)
#define alloca __builtin_alloca
/* Macro to control the number of undefined references printed */
#define MAX_UREFS_PRINTED 10
/* Align to power-of-two boundary */
#define PALIGN(x,p) (((x) + (u_long)(p) - 1) & (-(u_long)(p)))
/* Align to machine dependent boundary */
#define MALIGN(x) PALIGN(x,MAX_ALIGNMENT)
/* Name this program was invoked by. */
/* System dependencies */
/* Define this to specify the default executable format. */
#define DEFAULT_MAGIC QMAGIC
#define DEFAULT_MAGIC ZMAGIC
* Ok. Following are the relocation information macros. If your
* system should not be able to use the default set (below), you must
* relocation_info: This must be typedef'd (or #define'd) to the type
* of structure that is stored in the relocation info section of your
* a.out files. Often this is defined in the a.out.h for your system.
* RELOC_ADDRESS (rval): Offset into the current section of the
* <whatever> to be relocated. *Must be an lvalue*.
* RELOC_EXTERN_P (rval): Is this relocation entry based on an
* external symbol (1), or was it fully resolved upon entering the
* loader (0) in which case some combination of the value in memory
* (if RELOC_MEMORY_ADD_P) and the extra (if RELOC_ADD_EXTRA) contains
* what the value of the relocation actually was. *Must be an lvalue*.
* RELOC_TYPE (rval): If this entry was fully resolved upon
* entering the loader, what type should it be relocated as?
* RELOC_SYMBOL (rval): If this entry was not fully resolved upon
* entering the loader, what is the index of it's symbol in the symbol
* table? *Must be a lvalue*.
* RELOC_MEMORY_ADD_P (rval): This should return true if the final
* relocation value output here should be added to memory, or if the
* section of memory described should simply be set to the relocation
* RELOC_ADD_EXTRA (rval): (Optional) This macro, if defined, gives
* an extra value to be added to the relocation value based on the
* individual relocation entry. *Must be an lvalue if defined*.
* RELOC_PCREL_P (rval): True if the relocation value described is
* RELOC_VALUE_RIGHTSHIFT (rval): Number of bits right to shift the
* final relocation value before putting it where it belongs.
* RELOC_TARGET_SIZE (rval): log to the base 2 of the number of
* bytes of size this relocation entry describes; 1 byte == 0; 2 bytes
* == 1; 4 bytes == 2, and etc. This is somewhat redundant (we could
* do everything in terms of the bit operators below), but having this
* macro could end up producing better code on machines without fancy
* bit twiddling. Also, it's easier to understand/code big/little
* endian distinctions with this macro.
* RELOC_TARGET_BITPOS (rval): The starting bit position within the
* object described in RELOC_TARGET_SIZE in which the relocation value
* RELOC_TARGET_BITSIZE (rval): How many bits are to be replaced
* with the bits of the relocation value. It may be assumed by the
* code that the relocation value will fit into this many bits. This
* may be larger than RELOC_TARGET_SIZE if such be useful.
* Things I haven't implemented
* ----------------------------
* Values for RELOC_TARGET_SIZE other than 0, 1, or 2.
* Pc relative relocation for External references.
#define RELOC_ADDRESS(r) ((r)->r_address)
#define RELOC_EXTERN_P(r) ((r)->r_extern)
#define RELOC_TYPE(r) ((r)->r_symbolnum)
#define RELOC_SYMBOL(r) ((r)->r_symbolnum)
#define RELOC_MEMORY_SUB_P(r) 0
#define RELOC_MEMORY_ADD_P(r) 1
#define RELOC_PCREL_P(r) ((r)->r_pcrel)
#define RELOC_VALUE_RIGHTSHIFT(r) 0
#if defined(RTLD) && defined(SUN_COMPAT)
#define RELOC_TARGET_SIZE(r) (2) /* !!!!! Sun BUG compatible */
#define RELOC_TARGET_SIZE(r) ((r)->r_length)
#define RELOC_TARGET_BITPOS(r) 0
#define RELOC_TARGET_BITSIZE(r) 32
#define RELOC_JMPTAB_P(r) ((r)->r_jmptable)
#define RELOC_BASEREL_P(r) ((r)->r_baserel)
#define RELOC_RELATIVE_P(r) ((r)->r_relative)
#define RELOC_COPY_P(r) ((r)->r_copy)
#define RELOC_LAZY_P(r) ((r)->r_jmptable)
#define CHECK_GOT_RELOC(r) ((r)->r_pcrel)
* Internal representation of relocation types
#define RELTYPE_JMPSLOT 2
#define RELTYPE_BASEREL 4
#define RELTYPE_RELATIVE 8
#define TEXT_START(x) N_TXTADDR(x)
#define DATA_START(x) N_DATADDR(x)
/* If a this type of symbol is encountered, its name is a warning
message to print each time the symbol referenced by the next symbol
table entry is referenced.
This feature may be used to allow backwards compatibility with
certain functions (eg. gets) but to discourage programmers from
So if, for example, you wanted to have ld print a warning whenever
the function "gets" was used in their C program, you would add the
following to the assembler file in which gets is defined:
.stabs "Obsolete function \"gets\" referenced",30,0,0,0
These .stabs do not necessarily have to be in the same file as the
gets function, they simply must exist somewhere in the compilation. */
#define N_WARNING 0x1E /* Warning message to print if symbol
#endif /* This is input to ld */
/* Special global symbol types understood by GNU LD. */
/* The following type indicates the definition of a symbol as being
an indirect reference to another symbol. The other symbol
appears as an undefined reference, immediately following this symbol.
Indirection is asymmetrical. The other symbol's value will be used
to satisfy requests for the indirect symbol, but not vice versa.
If the other symbol does not have a definition, libraries will
be searched to find a definition.
So, for example, the following two lines placed in an assembler
input file would result in an object file which would direct gnu ld
to resolve all references to symbol "foo" as references to symbol
Note that (11 == (N_INDR | N_EXT)) and (1 == (N_UNDF | N_EXT)). */
/* The following symbols refer to set elements. These are expected
only in input to the loader; they should not appear in loader
output (unless relocatable output is requested). To be recognized
by the loader, the input symbols must have their N_EXT bit set.
All the N_SET[ATDB] symbols with the same name form one set. The
loader collects all of these elements at load time and outputs a
Space (an array of 32 bit words) is allocated for the set in the
data section, and the n_value field of each set element value is
stored into one word of the array.
The first word of the array is the length of the set (number of
elements). The last word of the vector is set to zero for possible
use by incremental loaders. The array is ordered by the linkage
order; the first symbols which the linker encounters will be first
In C syntax this looks like:
unsigned int vector[length];
unsigned int always_zero;
Before being placed into the array, each element is relocated
according to its type. This allows the loader to create an array
of pointers to objects automatically. N_SETA type symbols will not
The address of the set is made into an N_SETV symbol
whose name is the same as the name of the set.
This symbol acts like a N_DATA global symbol
in that it can satisfy undefined external references.
For the purposes of determining whether or not to load in a library
file, set element definitions are not considered "real
definitions"; they will not cause the loading of a library
If relocatable output is requested, none of this processing is
done. The symbols are simply relocated and passed through to the
So, for example, the following three lines of assembler code
(whether in one file or scattered between several different ones)
will produce a three element vector (total length is five words;
see above), referenced by the symbol "_xyzzy", which will have the
addresses of the routines _init1, _init2, and _init3.
*NOTE*: If symbolic addresses are used in the n_value field of the
defining .stabs, those symbols must be defined in the same file as
that containing the .stabs.
.stabs "_xyzzy",23,0,0,_init1
.stabs "_xyzzy",23,0,0,_init2
.stabs "_xyzzy",23,0,0,_init3
Note that (23 == (N_SETT | N_EXT)). */
#define N_SETA 0x14 /* Absolute set element symbol */
#endif /* This is input to LD, in a .o file. */
#define N_SETT 0x16 /* Text set element symbol */
#endif /* This is input to LD, in a .o file. */
#define N_SETD 0x18 /* Data set element symbol */
#endif /* This is input to LD, in a .o file. */
#define N_SETB 0x1A /* Bss set element symbol */
#endif /* This is input to LD, in a .o file. */
/* Macros dealing with the set element symbols defined in a.out.h */
#define SET_ELEMENT_P(x) ((x) >= N_SETA && (x) <= (N_SETB|N_EXT))
#define TYPE_OF_SET_ELEMENT(x) ((x) - N_SETA + N_ABS)
#define N_SETV 0x1C /* Pointer to set vector in data area. */
#endif /* This is output from LD. */
/* Line number for the data section. This is to be used to describe
the source location of a variable declaration. */
#define N_DSLINE (N_SLINE+N_DATA-N_TEXT)
/* Line number for the bss section. This is to be used to describe
the source location of a variable declaration. */
#define N_BSLINE (N_SLINE+N_BSS-N_TEXT)
#endif /* not __GNU_STAB__ */
typedef struct localsymbol
{
struct nzlist nzlist
; /* n[z]list from file */
struct glosym
*symbol
; /* Corresponding global symbol,
struct localsymbol
*next
; /* List of definitions */
struct file_entry
*entry
; /* Backpointer to file */
long gotslot_offset
; /* Position in GOT, if any */
int symbolnum
; /* Position in output nlist */
#define LS_L_SYMBOL 1 /* Local symbol starts with an `L' */
#define LS_WRITE 2 /* Symbol goes in output symtable */
#define LS_RENAME 4 /* xlat name to `<file>.<name>' */
#define LS_GOTSLOTCLAIMED 8 /* This symbol has a GOT entry */
* Global symbol data is recorded in these structures, one for each global
* symbol. They are found via hashing in 'symtab', which points to a vector
* of buckets. Each bucket is a chain of these structures through the link
struct glosym
*link
; /* Next symbol hash bucket. */
char *name
; /* Name of this symbol. */
long value
; /* Value of this symbol */
localsymbol_t
*refs
; /* Chain of local symbols from object files pertaining to this global
localsymbol_t
*sorefs
;/* Same for local symbols from shared char *warning
; /* message, from N_WARNING nlists */
int common_size
; /* Common size */
int symbolnum
; /* Symbol index in output symbol table */
int rrs_symbolnum
; /* Symbol index in RRS symbol table */
struct nlist
*def_nlist
; /* The local symbol that gave this
global symbol its definition */
char defined
; /* Definition of this symbol */
char so_defined
; /* Definition of this symbol in a shared
object. These go into the RRS symbol table */
u_char undef_refs
; /* Count of number of "undefined" messages printed for this symbol */
u_char mult_defs
; /* Same for "multiply defined" symbols */ struct glosym
*alias
; /* For symbols of type N_INDR, this
points at the real symbol. */
int setv_count
; /* Number of elements in N_SETV symbols */
int size
; /* Size of this symbol (either from N_SIZE
symbols or a from shared object's RRS */
int aux
; /* Auxiliary type information conveyed in
the `n_other' field of nlists */
/* The offset into one of the RRS tables, -1 if not used */
#define GS_DEFINED 1 /* Symbol has definition (notyetused)*/
#define GS_REFERENCED 2 /* Symbol is referred to by something
#define GS_TRACE 4 /* Symbol will be traced */
#define GS_JMPSLOTCLAIMED 8 /* */
#define GS_GOTSLOTCLAIMED 0x10 /* Some state bits concerning */
#define GS_CPYRELOCRESERVED 0x20 /* entries in GOT and PLT tables */
#define GS_CPYRELOCCLAIMED 0x40 /* */
/* Number of buckets in symbol hash table */
/* The symbol hash table: a vector of SYMTABSIZE pointers to struct glosym. */
#define FOR_EACH_SYMBOL(i,sp) { \
for (i = 0; i < SYMTABSIZE; i++) { \
for (sp = symtab[i]; sp; sp = sp->link)
#define END_EACH_SYMBOL }}
/* # of global symbols referenced and not defined. */
extern int undefined_global_sym_count
;
/* # of undefined symbols referenced by shared objects */
extern int undefined_shobj_sym_count
;
/* # of multiply defined symbols. */
extern int multiple_def_count
;
/* # of common symbols. */
extern int common_defined_global_count
;
/* # of warning symbols encountered. */
extern int warning_count
;
* Define a linked list of strings which define symbols which should be
* treated as set elements even though they aren't. Any symbol with a prefix
* matching one of these should be treated as a set element.
* This is to make up for deficiencies in many assemblers which aren't willing
* to pass any stabs through to the loader which they don't understand.
struct string_list_element
{
struct string_list_element
*next
;
extern symbol
*entry_symbol
; /* the entry symbol, if any */
extern symbol
*edata_symbol
; /* the symbol _edata */
extern symbol
*etext_symbol
; /* the symbol _etext */
extern symbol
*end_symbol
; /* the symbol _end */
extern symbol
*got_symbol
; /* the symbol __GLOBAL_OFFSET_TABLE_ */
extern symbol
*dynamic_symbol
; /* the symbol __DYNAMIC */
* Each input file, and each library member ("subfile") being loaded, has a
* `file_entry' structure for it.
* For files specified by command args, these are contained in the vector which
* `file_table' points to.
* For library members, they are dynamically allocated, and chained through the
* `chain' field. The chain is found in the `subfiles' field of the
* `file_entry'. The `file_entry' objects for the members have `superfile'
* fields pointing to the one for the library.
char *filename
; /* Name of this file. */
* Name to use for the symbol giving address of text start Usually
* the same as filename, but for a file spec'd with -l this is the -l
* switch itself rather than the filename.
struct exec header
; /* The file's a.out header. */
localsymbol_t
*symbols
; /* Symbol table of the file. */ int nsymbols
; /* Number of symbols in above array. */
int string_size
; /* Size in bytes of string table. */
char *strings
; /* Pointer to the string table when
in core, NULL otherwise */
int strings_offset
; /* Offset of string table,
(normally N_STROFF() + 4) */
* Next two used only if `relocatable_output' or if needed for
* output of undefined reference line numbers.
struct relocation_info
*textrel
; /* Text relocations */
int ntextrel
; /* # of text relocations */
struct relocation_info
*datarel
; /* Data relocations */
int ndatarel
; /* # of data relocations */
* Relation of this file's segments to the output file.
int text_start_address
; /* Start of this file's text segment
in the output file core image. */
int data_start_address
; /* Start of this file's data segment
in the output file core image. */
int bss_start_address
; /* Start of this file's bss segment
in the output file core image. */
struct file_entry
*subfiles
; /* For a library, points to chain of
entries for the library members. */
struct file_entry
*superfile
; /* For library member, points to the
struct file_entry
*chain
; /* For library member, points to next
entry for next member. */
int starting_offset
; /* For a library member, offset of the
member within the archive. Zero for
files that are not library members.*/
int total_size
; /* Size of contents of this file,
struct file_entry
*silly_archive
;/* For shared libraries which have
int lib_major
, lib_minor
; /* Version numbers of a shared object */
#define E_IS_LIBRARY 1 /* File is a an archive */
#define E_HEADER_VALID 2 /* File's header has been read */
#define E_SEARCH_DIRS 4 /* Search directories for file */
#define E_SEARCH_DYNAMIC 8 /* Search for shared libs allowed */
#define E_JUST_SYMS 0x10 /* File is used for incremental load */
#define E_DYNAMIC 0x20 /* File is a shared object */
#define E_SCRAPPED 0x40 /* Ignore this file */
#define E_SYMBOLS_USED 0x80 /* Symbols from this entry were used */
* Section start addresses.
extern int text_size
; /* total size of text. */
extern int text_start
; /* start of text */
extern int text_pad
; /* clear space between text and data */
extern int data_size
; /* total size of data. */
extern int data_start
; /* start of data */
extern int data_pad
; /* part of bss segment within data */
extern int bss_size
; /* total size of bss. */
extern int bss_start
; /* start of bss */
extern int text_reloc_size
; /* total size of text relocation. */
extern int data_reloc_size
; /* total size of data relocation. */
* Runtime Relocation Section (RRS).
* This describes the data structures that go into the output text and data
* segments to support the run-time linker. The RRS can be empty (plain old
* static linking), or can just exist of GOT and PLT entries (in case of
* statically linked PIC code).
extern int rrs_section_type
; /* What's in the RRS section */
extern int rrs_text_size
; /* Size of RRS text additions */
extern int rrs_text_start
; /* Location of above */
extern int rrs_data_size
; /* Size of RRS data additions */
extern int rrs_data_start
; /* Location of above */
/* Version number to put in __DYNAMIC (set by -V) */
#ifndef DEFAULT_SOVERSION
#define DEFAULT_SOVERSION LD_VERSION_BSD
extern int pc_relocation
; /* Current PC reloc value */
extern int number_of_shobjs
; /* # of shared objects linked in */
#define DYNAMIC 1 /* Consider shared libraries */
#define SYMBOLIC 2 /* Force symbolic resolution */
#define FORCEARCHIVE 4 /* Force inclusion of all members
#define SHAREABLE 8 /* Build a shared object */
#define SILLYARCHIVE 16 /* Process .sa companions, if any */
extern int outdesc
; /* Output file descriptor. */
extern struct exec outheader
; /* Output file header. */
extern int magic
; /* Output file magic. */
extern int relocatable_output
;
extern char **search_dirs
; /* Directories to search for libraries. */
extern int n_search_dirs
; /* Length of above. */
extern int write_map
; /* write a load map (`-M') */
extern void (*fatal_cleanup_hook
)__P((void));
void read_header
__P((int, struct file_entry
*));
void read_entry_symbols
__P((int, struct file_entry
*));
void read_entry_strings
__P((int, struct file_entry
*));
void read_entry_relocation
__P((int, struct file_entry
*));
void enter_file_symbols
__P((struct file_entry
*));
void read_file_symbols
__P((struct file_entry
*));
void mywrite
__P((void *, int, int, int));
void perror_name
__P((char *));
void perror_file
__P((struct file_entry
*));
void fatal_with_file
__P((char *, struct file_entry
*, ...));
void print_symbols
__P((FILE *));
char *get_file_name
__P((struct file_entry
*));
void print_file_name
__P((struct file_entry
*, FILE *));
void prline_file_name
__P((struct file_entry
*, FILE *));
int do_warnings
__P((FILE *));
void *xmalloc
__P((int));
void *xrealloc
__P((void *, int));
void fatal
__P((char *, ...));
void error
__P((char *, ...));
void padfile
__P((int,int));
char *concat
__P((const char *, const char *, const char *));
int parse
__P((char *, char *, char *));
void symtab_init
__P((int));
symbol
*getsym
__P((char *)), *getsym_soft
__P((char *));void search_library
__P((int, struct file_entry
*));
void read_shared_object
__P((int, struct file_entry
*));
int findlib
__P((struct file_entry
*));
char *findshlib
__P((char *, int *, int *, int));
void add_search_dir
__P((char *));
void std_search_dirs
__P((char *));
void init_rrs
__P((void));
int rrs_add_shobj
__P((struct file_entry
*));
void alloc_rrs_reloc
__P((struct file_entry
*, symbol
*));
void alloc_rrs_segment_reloc
__P((struct file_entry
*, struct relocation_info
*));
void alloc_rrs_jmpslot
__P((struct file_entry
*, symbol
*));
void alloc_rrs_gotslot
__P((struct file_entry
*, struct relocation_info
*, localsymbol_t
*));
void alloc_rrs_cpy_reloc
__P((struct file_entry
*, symbol
*));
int claim_rrs_reloc
__P((struct file_entry
*, struct relocation_info
*, symbol
*, long *));
long claim_rrs_jmpslot
__P((struct file_entry
*, struct relocation_info
*, symbol
*, long));
long claim_rrs_gotslot
__P((struct file_entry
*, struct relocation_info
*, struct localsymbol
*, long));
long claim_rrs_internal_gotslot
__P((struct file_entry
*, struct relocation_info
*, struct localsymbol
*, long));
void claim_rrs_cpy_reloc
__P((struct file_entry
*, struct relocation_info
*, symbol
*));
void claim_rrs_segment_reloc
__P((struct file_entry
*, struct relocation_info
*));
void md_init_header
__P((struct exec
*, int, int));
long md_get_addend
__P((struct relocation_info
*, unsigned char *));
void md_relocate
__P((struct relocation_info
*, long, unsigned char *, int));
void md_make_jmpslot
__P((jmpslot_t
*, long, long));
void md_fix_jmpslot
__P((jmpslot_t
*, long, u_long
));
int md_make_reloc
__P((struct relocation_info
*, struct relocation_info
*, int));
void md_make_jmpreloc
__P((struct relocation_info
*, struct relocation_info
*, int));
void md_make_gotreloc
__P((struct relocation_info
*, struct relocation_info
*, int));
void md_make_copyreloc
__P((struct relocation_info
*, struct relocation_info
*));
void md_swapin_exec_hdr
__P((struct exec
*));
void md_swapout_exec_hdr
__P((struct exec
*));
void md_swapin_reloc
__P((struct relocation_info
*, int));
void md_swapout_reloc
__P((struct relocation_info
*, int));
void md_swapout_jmpslot
__P((jmpslot_t
*, int));
void swap_longs
__P((long *, int));
void swap_symbols
__P((struct nlist
*, int));
void swap_zsymbols
__P((struct nzlist
*, int));
void swap_ranlib_hdr
__P((struct ranlib
*, int));
void swap__dynamic
__P((struct link_dynamic
*));
void swap_section_dispatch_table
__P((struct section_dispatch_table
*));
void swap_so_debug
__P((struct so_debug
*));
void swapin_sod
__P((struct sod
*, int));
void swapout_sod
__P((struct sod
*, int));
void swapout_fshash
__P((struct fshash
*, int));
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