2 * $FreeBSD: src/gnu/usr.bin/ld/ld.h,v 1.21 1999/08/27 23:36:01 peter Exp $
5 * This code is derived from software copyrighted by the Free Software
8 * Modified 1991 by Donn Seeley at UUNET Technologies, Inc.
18 #define min(a,b) ((a) < (b) ? (a) : (b))
29 /* If compiled with GNU C, use the built-in alloca */
30 #if defined(__GNUC__) || defined(sparc)
31 #define alloca __builtin_alloca
37 /* Macro to control the number of undefined references printed */
38 #define MAX_UREFS_PRINTED 10
40 /* Align to power-of-two boundary */
41 #define PALIGN(x,p) (((x) + (u_long)(p) - 1) & (-(u_long)(p)))
43 /* Align to machine dependent boundary */
44 #define MALIGN(x) PALIGN(x,MAX_ALIGNMENT)
46 /* Define this to specify the default executable format. */
49 #define DEFAULT_MAGIC QMAGIC
52 #define DEFAULT_MAGIC ZMAGIC
56 #ifdef DEMANGLE_CPLUSPLUS
57 extern char *demangle __P((char*));
59 #define demangle(name) name
63 * Ok. Following are the relocation information macros. If your
64 * system should not be able to use the default set (below), you must
65 * define the following:
67 * relocation_info: This must be typedef'd (or #define'd) to the type
68 * of structure that is stored in the relocation info section of your
69 * a.out files. Often this is defined in the a.out.h for your system.
71 * RELOC_ADDRESS (rval): Offset into the current section of the
72 * <whatever> to be relocated. *Must be an lvalue*.
74 * RELOC_EXTERN_P (rval): Is this relocation entry based on an
75 * external symbol (1), or was it fully resolved upon entering the
76 * loader (0) in which case some combination of the value in memory
77 * (if RELOC_MEMORY_ADD_P) and the extra (if RELOC_ADD_EXTRA) contains
78 * what the value of the relocation actually was. *Must be an lvalue*.
80 * RELOC_TYPE (rval): If this entry was fully resolved upon
81 * entering the loader, what type should it be relocated as?
83 * RELOC_SYMBOL (rval): If this entry was not fully resolved upon
84 * entering the loader, what is the index of it's symbol in the symbol
85 * table? *Must be a lvalue*.
87 * RELOC_MEMORY_ADD_P (rval): This should return true if the final
88 * relocation value output here should be added to memory, or if the
89 * section of memory described should simply be set to the relocation
92 * RELOC_ADD_EXTRA (rval): (Optional) This macro, if defined, gives
93 * an extra value to be added to the relocation value based on the
94 * individual relocation entry. *Must be an lvalue if defined*.
96 * RELOC_PCREL_P (rval): True if the relocation value described is
99 * RELOC_VALUE_RIGHTSHIFT (rval): Number of bits right to shift the
100 * final relocation value before putting it where it belongs.
102 * RELOC_TARGET_SIZE (rval): log to the base 2 of the number of
103 * bytes of size this relocation entry describes; 1 byte == 0; 2 bytes
104 * == 1; 4 bytes == 2, and etc. This is somewhat redundant (we could
105 * do everything in terms of the bit operators below), but having this
106 * macro could end up producing better code on machines without fancy
107 * bit twiddling. Also, it's easier to understand/code big/little
108 * endian distinctions with this macro.
110 * RELOC_TARGET_BITPOS (rval): The starting bit position within the
111 * object described in RELOC_TARGET_SIZE in which the relocation value
114 * RELOC_TARGET_BITSIZE (rval): How many bits are to be replaced
115 * with the bits of the relocation value. It may be assumed by the
116 * code that the relocation value will fit into this many bits. This
117 * may be larger than RELOC_TARGET_SIZE if such be useful.
120 * Things I haven't implemented
121 * ----------------------------
123 * Values for RELOC_TARGET_SIZE other than 0, 1, or 2.
125 * Pc relative relocation for External references.
132 #ifndef RELOC_ADDRESS
134 #define RELOC_ADDRESS(r) ((r)->r_address)
135 #define RELOC_EXTERN_P(r) ((r)->r_extern)
136 #define RELOC_TYPE(r) ((r)->r_symbolnum)
137 #define RELOC_SYMBOL(r) ((r)->r_symbolnum)
138 #define RELOC_MEMORY_SUB_P(r) 0
139 #define RELOC_MEMORY_ADD_P(r) 1
140 #undef RELOC_ADD_EXTRA
141 #define RELOC_PCREL_P(r) ((r)->r_pcrel)
142 #define RELOC_VALUE_RIGHTSHIFT(r) 0
143 #if defined(RTLD) && defined(SUN_COMPAT)
144 #define RELOC_TARGET_SIZE(r) (2) /* !!!!! Sun BUG compatible */
146 #define RELOC_TARGET_SIZE(r) ((r)->r_length)
148 #define RELOC_TARGET_BITPOS(r) 0
149 #define RELOC_TARGET_BITSIZE(r) 32
160 #define TEXT_START(x) N_TXTADDR(x)
164 #define DATA_START(x) N_DATADDR(x)
167 /* If a this type of symbol is encountered, its name is a warning
168 message to print each time the symbol referenced by the next symbol
169 table entry is referenced.
171 This feature may be used to allow backwards compatibility with
172 certain functions (eg. gets) but to discourage programmers from
175 So if, for example, you wanted to have ld print a warning whenever
176 the function "gets" was used in their C program, you would add the
177 following to the assembler file in which gets is defined:
179 .stabs "Obsolete function \"gets\" referenced",30,0,0,0
180 .stabs "_gets",1,0,0,0
182 These .stabs do not necessarily have to be in the same file as the
183 gets function, they simply must exist somewhere in the compilation. */
186 #define N_WARNING 0x1E /* Warning message to print if symbol
188 #endif /* This is input to ld */
190 /* Special global symbol types understood by GNU LD. */
192 /* The following type indicates the definition of a symbol as being
193 an indirect reference to another symbol. The other symbol
194 appears as an undefined reference, immediately following this symbol.
196 Indirection is asymmetrical. The other symbol's value will be used
197 to satisfy requests for the indirect symbol, but not vice versa.
198 If the other symbol does not have a definition, libraries will
199 be searched to find a definition.
201 So, for example, the following two lines placed in an assembler
202 input file would result in an object file which would direct gnu ld
203 to resolve all references to symbol "foo" as references to symbol
206 .stabs "_foo",11,0,0,0
207 .stabs "_bar",1,0,0,0
209 Note that (11 == (N_INDR | N_EXT)) and (1 == (N_UNDF | N_EXT)). */
215 /* The following symbols refer to set elements. These are expected
216 only in input to the loader; they should not appear in loader
217 output (unless relocatable output is requested). To be recognized
218 by the loader, the input symbols must have their N_EXT bit set.
219 All the N_SET[ATDB] symbols with the same name form one set. The
220 loader collects all of these elements at load time and outputs a
221 vector for each name.
222 Space (an array of 32 bit words) is allocated for the set in the
223 data section, and the n_value field of each set element value is
224 stored into one word of the array.
225 The first word of the array is the length of the set (number of
226 elements). The last word of the vector is set to zero for possible
227 use by incremental loaders. The array is ordered by the linkage
228 order; the first symbols which the linker encounters will be first
231 In C syntax this looks like:
235 unsigned int vector[length];
236 unsigned int always_zero;
239 Before being placed into the array, each element is relocated
240 according to its type. This allows the loader to create an array
241 of pointers to objects automatically. N_SETA type symbols will not
244 The address of the set is made into an N_SETV symbol
245 whose name is the same as the name of the set.
246 This symbol acts like a N_DATA global symbol
247 in that it can satisfy undefined external references.
249 For the purposes of determining whether or not to load in a library
250 file, set element definitions are not considered "real
251 definitions"; they will not cause the loading of a library
254 If relocatable output is requested, none of this processing is
255 done. The symbols are simply relocated and passed through to the
258 So, for example, the following three lines of assembler code
259 (whether in one file or scattered between several different ones)
260 will produce a three element vector (total length is five words;
261 see above), referenced by the symbol "_xyzzy", which will have the
262 addresses of the routines _init1, _init2, and _init3.
264 *NOTE*: If symbolic addresses are used in the n_value field of the
265 defining .stabs, those symbols must be defined in the same file as
266 that containing the .stabs.
268 .stabs "_xyzzy",23,0,0,_init1
269 .stabs "_xyzzy",23,0,0,_init2
270 .stabs "_xyzzy",23,0,0,_init3
272 Note that (23 == (N_SETT | N_EXT)). */
275 #define N_SETA 0x14 /* Absolute set element symbol */
276 #endif /* This is input to LD, in a .o file. */
279 #define N_SETT 0x16 /* Text set element symbol */
280 #endif /* This is input to LD, in a .o file. */
283 #define N_SETD 0x18 /* Data set element symbol */
284 #endif /* This is input to LD, in a .o file. */
287 #define N_SETB 0x1A /* Bss set element symbol */
288 #endif /* This is input to LD, in a .o file. */
290 /* Macros dealing with the set element symbols defined in a.out.h */
291 #define SET_ELEMENT_P(x) ((x) >= N_SETA && (x) <= (N_SETB|N_EXT))
292 #define TYPE_OF_SET_ELEMENT(x) ((x) - N_SETA + N_ABS)
295 #define N_SETV 0x1C /* Pointer to set vector in data area. */
296 #endif /* This is output from LD. */
300 /* Line number for the data section. This is to be used to describe
301 the source location of a variable declaration. */
303 #define N_DSLINE (N_SLINE+N_DATA-N_TEXT)
306 /* Line number for the bss section. This is to be used to describe
307 the source location of a variable declaration. */
309 #define N_BSLINE (N_SLINE+N_BSS-N_TEXT)
311 #endif /* not __GNU_STAB__ */
314 /* Number of buckets in symbol hash table */
315 #define SYMTABSIZE 1009
317 /* # of global symbols referenced and not defined. */
318 extern int undefined_global_sym_count;
320 /* # of weak symbols referenced and not defined. */
321 extern int undefined_weak_sym_count;
323 /* # of undefined symbols referenced by shared objects */
324 extern int undefined_shobj_sym_count;
326 /* # of multiply defined symbols. */
327 extern int multiple_def_count;
329 /* # of common symbols. */
330 extern int common_defined_global_count;
332 /* # of warning symbols encountered. */
333 extern int warn_sym_count;
334 extern int list_warning_symbols;
337 * Define a linked list of strings which define symbols which should be
338 * treated as set elements even though they aren't. Any symbol with a prefix
339 * matching one of these should be treated as a set element.
341 * This is to make up for deficiencies in many assemblers which aren't willing
342 * to pass any stabs through to the loader which they don't understand.
344 struct string_list_element {
346 struct string_list_element *next;
350 #ifndef __symbol_defined__
351 #define __symbol_defined__
352 typedef struct glosym symbol;
355 extern symbol *entry_symbol; /* the entry symbol, if any */
356 extern symbol *edata_symbol; /* the symbol _edata */
357 extern symbol *etext_symbol; /* the symbol _etext */
358 extern symbol *end_symbol; /* the symbol _end */
361 * Section start addresses.
363 extern int text_size; /* total size of text. */
364 extern int text_start; /* start of text */
365 extern int text_pad; /* clear space between text and data */
366 extern int data_size; /* total size of data. */
367 extern int data_start; /* start of data */
368 extern int data_pad; /* part of bss segment within data */
370 extern int bss_size; /* total size of bss. */
371 extern int bss_start; /* start of bss */
373 extern int text_reloc_size; /* total size of text relocation. */
374 extern int data_reloc_size; /* total size of data relocation. */
376 extern int magic; /* Output file magic. */
377 extern int relocatable_output;
379 /* Size of a page. */
380 extern int page_size;
382 extern char **search_dirs; /* Directories to search for libraries. */
383 extern int n_search_dirs; /* Length of above. */
385 extern int write_map; /* write a load map (`-M') */