Commit | Line | Data |
---|---|---|
c906108c | 1 | /* Find a variable's value in memory, for GDB, the GNU debugger. |
1bac305b AC |
2 | |
3 | Copyright 1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994, | |
990a07ab AC |
4 | 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2003, 2004, 2005 Free |
5 | Software Foundation, Inc. | |
c906108c | 6 | |
c5aa993b | 7 | This file is part of GDB. |
c906108c | 8 | |
c5aa993b JM |
9 | This program is free software; you can redistribute it and/or modify |
10 | it under the terms of the GNU General Public License as published by | |
11 | the Free Software Foundation; either version 2 of the License, or | |
12 | (at your option) any later version. | |
c906108c | 13 | |
c5aa993b JM |
14 | This program is distributed in the hope that it will be useful, |
15 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
16 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
17 | GNU General Public License for more details. | |
c906108c | 18 | |
c5aa993b JM |
19 | You should have received a copy of the GNU General Public License |
20 | along with this program; if not, write to the Free Software | |
21 | Foundation, Inc., 59 Temple Place - Suite 330, | |
22 | Boston, MA 02111-1307, USA. */ | |
c906108c SS |
23 | |
24 | #include "defs.h" | |
25 | #include "symtab.h" | |
26 | #include "gdbtypes.h" | |
27 | #include "frame.h" | |
28 | #include "value.h" | |
29 | #include "gdbcore.h" | |
30 | #include "inferior.h" | |
31 | #include "target.h" | |
32 | #include "gdb_string.h" | |
14e534aa | 33 | #include "gdb_assert.h" |
c906108c | 34 | #include "floatformat.h" |
c5aa993b | 35 | #include "symfile.h" /* for overlay functions */ |
4e052eda | 36 | #include "regcache.h" |
eb8bc282 | 37 | #include "user-regs.h" |
fe898f56 | 38 | #include "block.h" |
c906108c | 39 | |
c906108c SS |
40 | /* Basic byte-swapping routines. GDB has needed these for a long time... |
41 | All extract a target-format integer at ADDR which is LEN bytes long. */ | |
42 | ||
43 | #if TARGET_CHAR_BIT != 8 || HOST_CHAR_BIT != 8 | |
44 | /* 8 bit characters are a pretty safe assumption these days, so we | |
45 | assume it throughout all these swapping routines. If we had to deal with | |
46 | 9 bit characters, we would need to make len be in bits and would have | |
47 | to re-write these routines... */ | |
c5aa993b | 48 | you lose |
c906108c SS |
49 | #endif |
50 | ||
a9ac8f51 | 51 | LONGEST |
0d509538 | 52 | extract_signed_integer (const gdb_byte *addr, int len) |
c906108c SS |
53 | { |
54 | LONGEST retval; | |
37611a2b AC |
55 | const unsigned char *p; |
56 | const unsigned char *startaddr = addr; | |
57 | const unsigned char *endaddr = startaddr + len; | |
c906108c SS |
58 | |
59 | if (len > (int) sizeof (LONGEST)) | |
8a3fe4f8 AC |
60 | error (_("\ |
61 | That operation is not available on integers of more than %d bytes."), | |
baa6f10b | 62 | (int) sizeof (LONGEST)); |
c906108c SS |
63 | |
64 | /* Start at the most significant end of the integer, and work towards | |
65 | the least significant. */ | |
d7449b42 | 66 | if (TARGET_BYTE_ORDER == BFD_ENDIAN_BIG) |
c906108c SS |
67 | { |
68 | p = startaddr; | |
69 | /* Do the sign extension once at the start. */ | |
c5aa993b | 70 | retval = ((LONGEST) * p ^ 0x80) - 0x80; |
c906108c SS |
71 | for (++p; p < endaddr; ++p) |
72 | retval = (retval << 8) | *p; | |
73 | } | |
74 | else | |
75 | { | |
76 | p = endaddr - 1; | |
77 | /* Do the sign extension once at the start. */ | |
c5aa993b | 78 | retval = ((LONGEST) * p ^ 0x80) - 0x80; |
c906108c SS |
79 | for (--p; p >= startaddr; --p) |
80 | retval = (retval << 8) | *p; | |
81 | } | |
82 | return retval; | |
83 | } | |
84 | ||
85 | ULONGEST | |
0d509538 | 86 | extract_unsigned_integer (const gdb_byte *addr, int len) |
c906108c SS |
87 | { |
88 | ULONGEST retval; | |
37611a2b AC |
89 | const unsigned char *p; |
90 | const unsigned char *startaddr = addr; | |
91 | const unsigned char *endaddr = startaddr + len; | |
c906108c SS |
92 | |
93 | if (len > (int) sizeof (ULONGEST)) | |
8a3fe4f8 AC |
94 | error (_("\ |
95 | That operation is not available on integers of more than %d bytes."), | |
baa6f10b | 96 | (int) sizeof (ULONGEST)); |
c906108c SS |
97 | |
98 | /* Start at the most significant end of the integer, and work towards | |
99 | the least significant. */ | |
100 | retval = 0; | |
d7449b42 | 101 | if (TARGET_BYTE_ORDER == BFD_ENDIAN_BIG) |
c906108c SS |
102 | { |
103 | for (p = startaddr; p < endaddr; ++p) | |
104 | retval = (retval << 8) | *p; | |
105 | } | |
106 | else | |
107 | { | |
108 | for (p = endaddr - 1; p >= startaddr; --p) | |
109 | retval = (retval << 8) | *p; | |
110 | } | |
111 | return retval; | |
112 | } | |
113 | ||
114 | /* Sometimes a long long unsigned integer can be extracted as a | |
115 | LONGEST value. This is done so that we can print these values | |
116 | better. If this integer can be converted to a LONGEST, this | |
117 | function returns 1 and sets *PVAL. Otherwise it returns 0. */ | |
118 | ||
119 | int | |
0d509538 AC |
120 | extract_long_unsigned_integer (const gdb_byte *addr, int orig_len, |
121 | LONGEST *pval) | |
c906108c | 122 | { |
0d509538 AC |
123 | const gdb_byte *p; |
124 | const gdb_byte *first_addr; | |
c906108c SS |
125 | int len; |
126 | ||
127 | len = orig_len; | |
d7449b42 | 128 | if (TARGET_BYTE_ORDER == BFD_ENDIAN_BIG) |
c906108c | 129 | { |
0d509538 AC |
130 | for (p = addr; |
131 | len > (int) sizeof (LONGEST) && p < addr + orig_len; | |
c906108c SS |
132 | p++) |
133 | { | |
134 | if (*p == 0) | |
135 | len--; | |
136 | else | |
137 | break; | |
138 | } | |
139 | first_addr = p; | |
140 | } | |
141 | else | |
142 | { | |
0d509538 AC |
143 | first_addr = addr; |
144 | for (p = addr + orig_len - 1; | |
145 | len > (int) sizeof (LONGEST) && p >= addr; | |
c906108c SS |
146 | p--) |
147 | { | |
148 | if (*p == 0) | |
149 | len--; | |
150 | else | |
151 | break; | |
152 | } | |
153 | } | |
154 | ||
155 | if (len <= (int) sizeof (LONGEST)) | |
156 | { | |
157 | *pval = (LONGEST) extract_unsigned_integer (first_addr, | |
158 | sizeof (LONGEST)); | |
159 | return 1; | |
160 | } | |
161 | ||
162 | return 0; | |
163 | } | |
164 | ||
4478b372 | 165 | |
4478b372 JB |
166 | /* Treat the bytes at BUF as a pointer of type TYPE, and return the |
167 | address it represents. */ | |
168 | CORE_ADDR | |
0d509538 | 169 | extract_typed_address (const gdb_byte *buf, struct type *type) |
4478b372 JB |
170 | { |
171 | if (TYPE_CODE (type) != TYPE_CODE_PTR | |
172 | && TYPE_CODE (type) != TYPE_CODE_REF) | |
8e65ff28 | 173 | internal_error (__FILE__, __LINE__, |
e2e0b3e5 AC |
174 | _("extract_typed_address: " |
175 | "type is not a pointer or reference")); | |
4478b372 JB |
176 | |
177 | return POINTER_TO_ADDRESS (type, buf); | |
178 | } | |
179 | ||
180 | ||
c906108c | 181 | void |
0d509538 | 182 | store_signed_integer (gdb_byte *addr, int len, LONGEST val) |
c906108c | 183 | { |
0d509538 AC |
184 | gdb_byte *p; |
185 | gdb_byte *startaddr = addr; | |
186 | gdb_byte *endaddr = startaddr + len; | |
c906108c SS |
187 | |
188 | /* Start at the least significant end of the integer, and work towards | |
189 | the most significant. */ | |
d7449b42 | 190 | if (TARGET_BYTE_ORDER == BFD_ENDIAN_BIG) |
c906108c SS |
191 | { |
192 | for (p = endaddr - 1; p >= startaddr; --p) | |
193 | { | |
194 | *p = val & 0xff; | |
195 | val >>= 8; | |
196 | } | |
197 | } | |
198 | else | |
199 | { | |
200 | for (p = startaddr; p < endaddr; ++p) | |
201 | { | |
202 | *p = val & 0xff; | |
203 | val >>= 8; | |
204 | } | |
205 | } | |
206 | } | |
207 | ||
208 | void | |
0d509538 | 209 | store_unsigned_integer (gdb_byte *addr, int len, ULONGEST val) |
c906108c SS |
210 | { |
211 | unsigned char *p; | |
c5aa993b | 212 | unsigned char *startaddr = (unsigned char *) addr; |
c906108c SS |
213 | unsigned char *endaddr = startaddr + len; |
214 | ||
215 | /* Start at the least significant end of the integer, and work towards | |
216 | the most significant. */ | |
d7449b42 | 217 | if (TARGET_BYTE_ORDER == BFD_ENDIAN_BIG) |
c906108c SS |
218 | { |
219 | for (p = endaddr - 1; p >= startaddr; --p) | |
220 | { | |
221 | *p = val & 0xff; | |
222 | val >>= 8; | |
223 | } | |
224 | } | |
225 | else | |
226 | { | |
227 | for (p = startaddr; p < endaddr; ++p) | |
228 | { | |
229 | *p = val & 0xff; | |
230 | val >>= 8; | |
231 | } | |
232 | } | |
233 | } | |
234 | ||
4478b372 JB |
235 | /* Store the address ADDR as a pointer of type TYPE at BUF, in target |
236 | form. */ | |
237 | void | |
0d509538 | 238 | store_typed_address (gdb_byte *buf, struct type *type, CORE_ADDR addr) |
4478b372 JB |
239 | { |
240 | if (TYPE_CODE (type) != TYPE_CODE_PTR | |
241 | && TYPE_CODE (type) != TYPE_CODE_REF) | |
8e65ff28 | 242 | internal_error (__FILE__, __LINE__, |
e2e0b3e5 AC |
243 | _("store_typed_address: " |
244 | "type is not a pointer or reference")); | |
4478b372 JB |
245 | |
246 | ADDRESS_TO_POINTER (type, buf, addr); | |
247 | } | |
248 | ||
249 | ||
250 | ||
376c9600 AC |
251 | /* Return a `value' with the contents of (virtual or cooked) register |
252 | REGNUM as found in the specified FRAME. The register's type is | |
7b83296f | 253 | determined by register_type(). |
c906108c | 254 | |
376c9600 AC |
255 | NOTE: returns NULL if register value is not available. Caller will |
256 | check return value or die! */ | |
c906108c | 257 | |
3d6d86c6 | 258 | struct value * |
376c9600 | 259 | value_of_register (int regnum, struct frame_info *frame) |
c906108c SS |
260 | { |
261 | CORE_ADDR addr; | |
262 | int optim; | |
3d6d86c6 | 263 | struct value *reg_val; |
ac2adee5 | 264 | int realnum; |
d9d9c31f | 265 | char raw_buffer[MAX_REGISTER_SIZE]; |
c906108c SS |
266 | enum lval_type lval; |
267 | ||
9564ee9f | 268 | /* User registers lie completely outside of the range of normal |
0406ec40 AC |
269 | registers. Catch them early so that the target never sees them. */ |
270 | if (regnum >= NUM_REGS + NUM_PSEUDO_REGS) | |
eb8bc282 | 271 | return value_of_user_reg (regnum, frame); |
0406ec40 | 272 | |
ac2adee5 | 273 | frame_register (frame, regnum, &optim, &lval, &addr, &realnum, raw_buffer); |
c906108c | 274 | |
c97dcfc7 AC |
275 | /* FIXME: cagney/2002-05-15: This test is just bogus. |
276 | ||
277 | It indicates that the target failed to supply a value for a | |
278 | register because it was "not available" at this time. Problem | |
279 | is, the target still has the register and so get saved_register() | |
280 | may be returning a value saved on the stack. */ | |
281 | ||
32178cab | 282 | if (register_cached (regnum) < 0) |
c5aa993b | 283 | return NULL; /* register value not available */ |
c906108c | 284 | |
7b83296f | 285 | reg_val = allocate_value (register_type (current_gdbarch, regnum)); |
c906108c | 286 | |
990a07ab | 287 | memcpy (value_contents_raw (reg_val), raw_buffer, |
01e1877c | 288 | register_size (current_gdbarch, regnum)); |
c906108c SS |
289 | VALUE_LVAL (reg_val) = lval; |
290 | VALUE_ADDRESS (reg_val) = addr; | |
9ee8fc9d | 291 | VALUE_REGNUM (reg_val) = regnum; |
feb13ab0 | 292 | set_value_optimized_out (reg_val, optim); |
0c16dd26 | 293 | VALUE_FRAME_ID (reg_val) = get_frame_id (frame); |
c906108c SS |
294 | return reg_val; |
295 | } | |
4478b372 JB |
296 | |
297 | /* Given a pointer of type TYPE in target form in BUF, return the | |
298 | address it represents. */ | |
299 | CORE_ADDR | |
b60c417a | 300 | unsigned_pointer_to_address (struct type *type, const gdb_byte *buf) |
4478b372 | 301 | { |
af1342ab | 302 | return extract_unsigned_integer (buf, TYPE_LENGTH (type)); |
4478b372 JB |
303 | } |
304 | ||
ac2e2ef7 | 305 | CORE_ADDR |
b60c417a | 306 | signed_pointer_to_address (struct type *type, const gdb_byte *buf) |
ac2e2ef7 AC |
307 | { |
308 | return extract_signed_integer (buf, TYPE_LENGTH (type)); | |
309 | } | |
4478b372 JB |
310 | |
311 | /* Given an address, store it as a pointer of type TYPE in target | |
312 | format in BUF. */ | |
313 | void | |
b60c417a AC |
314 | unsigned_address_to_pointer (struct type *type, gdb_byte *buf, |
315 | CORE_ADDR addr) | |
4478b372 | 316 | { |
fbd9dcd3 | 317 | store_unsigned_integer (buf, TYPE_LENGTH (type), addr); |
4478b372 JB |
318 | } |
319 | ||
ac2e2ef7 | 320 | void |
b60c417a | 321 | address_to_signed_pointer (struct type *type, gdb_byte *buf, CORE_ADDR addr) |
ac2e2ef7 AC |
322 | { |
323 | store_signed_integer (buf, TYPE_LENGTH (type), addr); | |
324 | } | |
c906108c SS |
325 | \f |
326 | /* Will calling read_var_value or locate_var_value on SYM end | |
327 | up caring what frame it is being evaluated relative to? SYM must | |
328 | be non-NULL. */ | |
329 | int | |
fba45db2 | 330 | symbol_read_needs_frame (struct symbol *sym) |
c906108c SS |
331 | { |
332 | switch (SYMBOL_CLASS (sym)) | |
333 | { | |
334 | /* All cases listed explicitly so that gcc -Wall will detect it if | |
c5aa993b | 335 | we failed to consider one. */ |
4c2df51b DJ |
336 | case LOC_COMPUTED: |
337 | case LOC_COMPUTED_ARG: | |
a67af2b9 AC |
338 | /* FIXME: cagney/2004-01-26: It should be possible to |
339 | unconditionally call the SYMBOL_OPS method when available. | |
d3efc286 | 340 | Unfortunately DWARF 2 stores the frame-base (instead of the |
a67af2b9 AC |
341 | function) location in a function's symbol. Oops! For the |
342 | moment enable this when/where applicable. */ | |
343 | return SYMBOL_OPS (sym)->read_needs_frame (sym); | |
4c2df51b | 344 | |
c906108c SS |
345 | case LOC_REGISTER: |
346 | case LOC_ARG: | |
347 | case LOC_REF_ARG: | |
348 | case LOC_REGPARM: | |
349 | case LOC_REGPARM_ADDR: | |
350 | case LOC_LOCAL: | |
351 | case LOC_LOCAL_ARG: | |
352 | case LOC_BASEREG: | |
353 | case LOC_BASEREG_ARG: | |
407caf07 | 354 | case LOC_HP_THREAD_LOCAL_STATIC: |
c906108c SS |
355 | return 1; |
356 | ||
357 | case LOC_UNDEF: | |
358 | case LOC_CONST: | |
359 | case LOC_STATIC: | |
360 | case LOC_INDIRECT: | |
361 | case LOC_TYPEDEF: | |
362 | ||
363 | case LOC_LABEL: | |
364 | /* Getting the address of a label can be done independently of the block, | |
c5aa993b JM |
365 | even if some *uses* of that address wouldn't work so well without |
366 | the right frame. */ | |
c906108c SS |
367 | |
368 | case LOC_BLOCK: | |
369 | case LOC_CONST_BYTES: | |
370 | case LOC_UNRESOLVED: | |
371 | case LOC_OPTIMIZED_OUT: | |
372 | return 0; | |
373 | } | |
374 | return 1; | |
375 | } | |
376 | ||
377 | /* Given a struct symbol for a variable, | |
378 | and a stack frame id, read the value of the variable | |
379 | and return a (pointer to a) struct value containing the value. | |
380 | If the variable cannot be found, return a zero pointer. | |
6e7f8b9c | 381 | If FRAME is NULL, use the deprecated_selected_frame. */ |
c906108c | 382 | |
3d6d86c6 | 383 | struct value * |
aa1ee363 | 384 | read_var_value (struct symbol *var, struct frame_info *frame) |
c906108c | 385 | { |
52f0bd74 | 386 | struct value *v; |
c906108c SS |
387 | struct type *type = SYMBOL_TYPE (var); |
388 | CORE_ADDR addr; | |
52f0bd74 | 389 | int len; |
c906108c | 390 | |
bb044262 DJ |
391 | if (SYMBOL_CLASS (var) == LOC_COMPUTED |
392 | || SYMBOL_CLASS (var) == LOC_COMPUTED_ARG | |
393 | || SYMBOL_CLASS (var) == LOC_REGISTER | |
394 | || SYMBOL_CLASS (var) == LOC_REGPARM) | |
395 | /* These cases do not use V. */ | |
396 | v = NULL; | |
397 | else | |
398 | { | |
399 | v = allocate_value (type); | |
400 | VALUE_LVAL (v) = lval_memory; /* The most likely possibility. */ | |
401 | } | |
c906108c SS |
402 | |
403 | len = TYPE_LENGTH (type); | |
404 | ||
7dd88986 DJ |
405 | /* FIXME drow/2003-09-06: this call to the selected frame should be |
406 | pushed upwards to the callers. */ | |
c5aa993b | 407 | if (frame == NULL) |
7dd88986 | 408 | frame = deprecated_safe_get_selected_frame (); |
c906108c SS |
409 | |
410 | switch (SYMBOL_CLASS (var)) | |
411 | { | |
412 | case LOC_CONST: | |
413 | /* Put the constant back in target format. */ | |
990a07ab | 414 | store_signed_integer (value_contents_raw (v), len, |
c906108c SS |
415 | (LONGEST) SYMBOL_VALUE (var)); |
416 | VALUE_LVAL (v) = not_lval; | |
417 | return v; | |
418 | ||
419 | case LOC_LABEL: | |
420 | /* Put the constant back in target format. */ | |
421 | if (overlay_debugging) | |
4478b372 JB |
422 | { |
423 | CORE_ADDR addr | |
424 | = symbol_overlayed_address (SYMBOL_VALUE_ADDRESS (var), | |
425 | SYMBOL_BFD_SECTION (var)); | |
990a07ab | 426 | store_typed_address (value_contents_raw (v), type, addr); |
4478b372 | 427 | } |
c906108c | 428 | else |
990a07ab | 429 | store_typed_address (value_contents_raw (v), type, |
4478b372 | 430 | SYMBOL_VALUE_ADDRESS (var)); |
c906108c SS |
431 | VALUE_LVAL (v) = not_lval; |
432 | return v; | |
433 | ||
434 | case LOC_CONST_BYTES: | |
435 | { | |
436 | char *bytes_addr; | |
437 | bytes_addr = SYMBOL_VALUE_BYTES (var); | |
990a07ab | 438 | memcpy (value_contents_raw (v), bytes_addr, len); |
c906108c SS |
439 | VALUE_LVAL (v) = not_lval; |
440 | return v; | |
441 | } | |
442 | ||
443 | case LOC_STATIC: | |
444 | if (overlay_debugging) | |
445 | addr = symbol_overlayed_address (SYMBOL_VALUE_ADDRESS (var), | |
446 | SYMBOL_BFD_SECTION (var)); | |
447 | else | |
448 | addr = SYMBOL_VALUE_ADDRESS (var); | |
449 | break; | |
450 | ||
451 | case LOC_INDIRECT: | |
f76febae AC |
452 | { |
453 | /* The import slot does not have a real address in it from the | |
454 | dynamic loader (dld.sl on HP-UX), if the target hasn't | |
455 | begun execution yet, so check for that. */ | |
456 | CORE_ADDR locaddr; | |
457 | struct value *loc; | |
458 | if (!target_has_execution) | |
8a3fe4f8 | 459 | error (_("\ |
c906108c | 460 | Attempt to access variable defined in different shared object or load module when\n\ |
8a3fe4f8 | 461 | addresses have not been bound by the dynamic loader. Try again when executable is running.")); |
c5aa993b | 462 | |
f76febae | 463 | locaddr = SYMBOL_VALUE_ADDRESS (var); |
00a4c844 | 464 | loc = value_at (lookup_pointer_type (type), locaddr); |
1aa20aa8 | 465 | addr = value_as_address (loc); |
bb044262 | 466 | break; |
f76febae | 467 | } |
c906108c SS |
468 | |
469 | case LOC_ARG: | |
470 | if (frame == NULL) | |
471 | return 0; | |
da62e633 | 472 | addr = get_frame_args_address (frame); |
c906108c SS |
473 | if (!addr) |
474 | return 0; | |
475 | addr += SYMBOL_VALUE (var); | |
476 | break; | |
477 | ||
478 | case LOC_REF_ARG: | |
f76febae AC |
479 | { |
480 | struct value *ref; | |
481 | CORE_ADDR argref; | |
482 | if (frame == NULL) | |
483 | return 0; | |
da62e633 | 484 | argref = get_frame_args_address (frame); |
f76febae AC |
485 | if (!argref) |
486 | return 0; | |
487 | argref += SYMBOL_VALUE (var); | |
00a4c844 | 488 | ref = value_at (lookup_pointer_type (type), argref); |
1aa20aa8 | 489 | addr = value_as_address (ref); |
f76febae AC |
490 | break; |
491 | } | |
c906108c SS |
492 | |
493 | case LOC_LOCAL: | |
494 | case LOC_LOCAL_ARG: | |
495 | if (frame == NULL) | |
496 | return 0; | |
da62e633 | 497 | addr = get_frame_locals_address (frame); |
c906108c SS |
498 | addr += SYMBOL_VALUE (var); |
499 | break; | |
500 | ||
501 | case LOC_BASEREG: | |
502 | case LOC_BASEREG_ARG: | |
407caf07 | 503 | case LOC_HP_THREAD_LOCAL_STATIC: |
c906108c | 504 | { |
3d6d86c6 | 505 | struct value *regval; |
c5aa993b | 506 | |
9ed10b08 ND |
507 | regval = value_from_register (lookup_pointer_type (type), |
508 | SYMBOL_BASEREG (var), frame); | |
509 | if (regval == NULL) | |
8a3fe4f8 | 510 | error (_("Value of base register not available.")); |
1aa20aa8 | 511 | addr = value_as_address (regval); |
c5aa993b JM |
512 | addr += SYMBOL_VALUE (var); |
513 | break; | |
c906108c | 514 | } |
c5aa993b | 515 | |
c906108c | 516 | case LOC_TYPEDEF: |
8a3fe4f8 | 517 | error (_("Cannot look up value of a typedef")); |
c906108c SS |
518 | break; |
519 | ||
520 | case LOC_BLOCK: | |
521 | if (overlay_debugging) | |
c5aa993b | 522 | VALUE_ADDRESS (v) = symbol_overlayed_address |
c906108c SS |
523 | (BLOCK_START (SYMBOL_BLOCK_VALUE (var)), SYMBOL_BFD_SECTION (var)); |
524 | else | |
525 | VALUE_ADDRESS (v) = BLOCK_START (SYMBOL_BLOCK_VALUE (var)); | |
526 | return v; | |
527 | ||
528 | case LOC_REGISTER: | |
529 | case LOC_REGPARM: | |
530 | case LOC_REGPARM_ADDR: | |
531 | { | |
532 | struct block *b; | |
533 | int regno = SYMBOL_VALUE (var); | |
3d6d86c6 | 534 | struct value *regval; |
c906108c SS |
535 | |
536 | if (frame == NULL) | |
537 | return 0; | |
ae767bfb | 538 | b = get_frame_block (frame, 0); |
c906108c SS |
539 | |
540 | if (SYMBOL_CLASS (var) == LOC_REGPARM_ADDR) | |
541 | { | |
542 | regval = value_from_register (lookup_pointer_type (type), | |
c5aa993b | 543 | regno, |
c906108c SS |
544 | frame); |
545 | ||
546 | if (regval == NULL) | |
8a3fe4f8 | 547 | error (_("Value of register variable not available.")); |
c906108c | 548 | |
1aa20aa8 | 549 | addr = value_as_address (regval); |
c906108c SS |
550 | VALUE_LVAL (v) = lval_memory; |
551 | } | |
552 | else | |
553 | { | |
554 | regval = value_from_register (type, regno, frame); | |
555 | ||
556 | if (regval == NULL) | |
8a3fe4f8 | 557 | error (_("Value of register variable not available.")); |
c906108c SS |
558 | return regval; |
559 | } | |
560 | } | |
561 | break; | |
562 | ||
4c2df51b DJ |
563 | case LOC_COMPUTED: |
564 | case LOC_COMPUTED_ARG: | |
a67af2b9 AC |
565 | /* FIXME: cagney/2004-01-26: It should be possible to |
566 | unconditionally call the SYMBOL_OPS method when available. | |
d3efc286 | 567 | Unfortunately DWARF 2 stores the frame-base (instead of the |
a67af2b9 AC |
568 | function) location in a function's symbol. Oops! For the |
569 | moment enable this when/where applicable. */ | |
570 | if (frame == 0 && SYMBOL_OPS (var)->read_needs_frame (var)) | |
571 | return 0; | |
572 | return SYMBOL_OPS (var)->read_variable (var, frame); | |
4c2df51b | 573 | |
c906108c SS |
574 | case LOC_UNRESOLVED: |
575 | { | |
576 | struct minimal_symbol *msym; | |
577 | ||
22abf04a | 578 | msym = lookup_minimal_symbol (DEPRECATED_SYMBOL_NAME (var), NULL, NULL); |
c906108c SS |
579 | if (msym == NULL) |
580 | return 0; | |
581 | if (overlay_debugging) | |
582 | addr = symbol_overlayed_address (SYMBOL_VALUE_ADDRESS (msym), | |
583 | SYMBOL_BFD_SECTION (msym)); | |
584 | else | |
585 | addr = SYMBOL_VALUE_ADDRESS (msym); | |
586 | } | |
587 | break; | |
588 | ||
589 | case LOC_OPTIMIZED_OUT: | |
590 | VALUE_LVAL (v) = not_lval; | |
feb13ab0 | 591 | set_value_optimized_out (v, 1); |
c906108c SS |
592 | return v; |
593 | ||
594 | default: | |
8a3fe4f8 | 595 | error (_("Cannot look up value of a botched symbol.")); |
c906108c SS |
596 | break; |
597 | } | |
598 | ||
599 | VALUE_ADDRESS (v) = addr; | |
dfa52d88 | 600 | set_value_lazy (v, 1); |
c906108c SS |
601 | return v; |
602 | } | |
603 | ||
604 | /* Return a value of type TYPE, stored in register REGNUM, in frame | |
0f2c5ba5 | 605 | FRAME. |
c906108c SS |
606 | |
607 | NOTE: returns NULL if register value is not available. | |
608 | Caller will check return value or die! */ | |
609 | ||
3d6d86c6 | 610 | struct value * |
fba45db2 | 611 | value_from_register (struct type *type, int regnum, struct frame_info *frame) |
c906108c | 612 | { |
ff2e87ac | 613 | struct gdbarch *gdbarch = get_frame_arch (frame); |
3d6d86c6 | 614 | struct value *v = allocate_value (type); |
c906108c | 615 | CHECK_TYPEDEF (type); |
c906108c | 616 | |
4589a601 JB |
617 | if (TYPE_LENGTH (type) == 0) |
618 | { | |
619 | /* It doesn't matter much what we return for this: since the | |
620 | length is zero, it could be anything. But if allowed to see | |
621 | a zero-length type, the register-finding loop below will set | |
622 | neither mem_stor nor reg_stor, and then report an internal | |
623 | error. | |
624 | ||
625 | Zero-length types can legitimately arise from declarations | |
f98c22d5 JB |
626 | like 'struct {}' (a GCC extension, not valid ISO C). GDB may |
627 | also create them when it finds bogus debugging information; | |
628 | for example, in GCC 2.95.4 and binutils 2.11.93.0.2, the | |
629 | STABS BINCL->EXCL compression process can create bad type | |
630 | numbers. GDB reads these as TYPE_CODE_UNDEF types, with zero | |
631 | length. (That bug is actually the only known way to get a | |
632 | zero-length value allocated to a register --- which is what | |
633 | it takes to make it here.) | |
4589a601 JB |
634 | |
635 | We'll just attribute the value to the original register. */ | |
636 | VALUE_LVAL (v) = lval_register; | |
637 | VALUE_ADDRESS (v) = regnum; | |
9ee8fc9d | 638 | VALUE_REGNUM (v) = regnum; |
4589a601 JB |
639 | } |
640 | else if (CONVERT_REGISTER_P (regnum, type)) | |
ff2e87ac AC |
641 | { |
642 | /* The ISA/ABI need to something weird when obtaining the | |
643 | specified value from this register. It might need to | |
644 | re-order non-adjacent, starting with REGNUM (see MIPS and | |
645 | i386). It might need to convert the [float] register into | |
646 | the corresponding [integer] type (see Alpha). The assumption | |
647 | is that REGISTER_TO_VALUE populates the entire value | |
648 | including the location. */ | |
990a07ab | 649 | REGISTER_TO_VALUE (frame, regnum, type, value_contents_raw (v)); |
25ae5d16 | 650 | VALUE_LVAL (v) = lval_register; |
ff2e87ac | 651 | VALUE_FRAME_ID (v) = get_frame_id (frame); |
9ee8fc9d | 652 | VALUE_REGNUM (v) = regnum; |
ff2e87ac AC |
653 | } |
654 | else | |
c906108c | 655 | { |
c906108c SS |
656 | int local_regnum; |
657 | int mem_stor = 0, reg_stor = 0; | |
658 | int mem_tracking = 1; | |
659 | CORE_ADDR last_addr = 0; | |
660 | CORE_ADDR first_addr = 0; | |
ff2e87ac AC |
661 | int first_realnum = regnum; |
662 | int len = TYPE_LENGTH (type); | |
663 | int value_bytes_copied; | |
664 | int optimized = 0; | |
665 | char *value_bytes = (char *) alloca (len + MAX_REGISTER_SIZE); | |
c906108c SS |
666 | |
667 | /* Copy all of the data out, whereever it may be. */ | |
ff2e87ac AC |
668 | for (local_regnum = regnum, value_bytes_copied = 0; |
669 | value_bytes_copied < len; | |
3acba339 | 670 | (value_bytes_copied += register_size (current_gdbarch, local_regnum), |
ff2e87ac AC |
671 | ++local_regnum)) |
672 | { | |
673 | int realnum; | |
674 | int optim; | |
675 | enum lval_type lval; | |
676 | CORE_ADDR addr; | |
677 | frame_register (frame, local_regnum, &optim, &lval, &addr, | |
678 | &realnum, value_bytes + value_bytes_copied); | |
679 | optimized += optim; | |
680 | if (register_cached (local_regnum) == -1) | |
681 | return NULL; /* register value not available */ | |
682 | ||
683 | if (regnum == local_regnum) | |
684 | { | |
c906108c | 685 | first_addr = addr; |
ff2e87ac AC |
686 | first_realnum = realnum; |
687 | } | |
688 | if (lval == lval_register) | |
689 | reg_stor++; | |
690 | else | |
691 | { | |
692 | mem_stor++; | |
693 | ||
25ae5d16 AC |
694 | /* FIXME: cagney/2004-11-12: I think this is trying to |
695 | check that the stored registers are adjacent in | |
696 | memory. It isn't doing a good job? */ | |
ff2e87ac AC |
697 | mem_tracking = (mem_tracking |
698 | && (regnum == local_regnum | |
699 | || addr == last_addr)); | |
700 | } | |
701 | last_addr = addr; | |
702 | } | |
703 | ||
25ae5d16 | 704 | if (mem_tracking && mem_stor && !reg_stor) |
c906108c SS |
705 | { |
706 | VALUE_LVAL (v) = lval_memory; | |
707 | VALUE_ADDRESS (v) = first_addr; | |
708 | } | |
25ae5d16 | 709 | else |
c906108c SS |
710 | { |
711 | VALUE_LVAL (v) = lval_register; | |
25ae5d16 AC |
712 | VALUE_FRAME_ID (v) = get_frame_id (frame); |
713 | VALUE_REGNUM (v) = regnum; | |
c906108c | 714 | } |
ff2e87ac | 715 | |
feb13ab0 | 716 | set_value_optimized_out (v, optimized); |
ff2e87ac | 717 | |
c906108c | 718 | /* Any structure stored in more than one register will always be |
ff2e87ac | 719 | an integral number of registers. Otherwise, you need to do |
c5aa993b JM |
720 | some fiddling with the last register copied here for little |
721 | endian machines. */ | |
ff2e87ac | 722 | if (TARGET_BYTE_ORDER == BFD_ENDIAN_BIG |
3acba339 | 723 | && len < register_size (current_gdbarch, regnum)) |
ff2e87ac | 724 | /* Big-endian, and we want less than full size. */ |
f5cf64a7 | 725 | set_value_offset (v, register_size (current_gdbarch, regnum) - len); |
ff2e87ac | 726 | else |
f5cf64a7 | 727 | set_value_offset (v, 0); |
990a07ab | 728 | memcpy (value_contents_raw (v), value_bytes + value_offset (v), len); |
c906108c | 729 | } |
c906108c SS |
730 | return v; |
731 | } | |
ff2e87ac | 732 | |
c906108c SS |
733 | \f |
734 | /* Given a struct symbol for a variable or function, | |
735 | and a stack frame id, | |
736 | return a (pointer to a) struct value containing the properly typed | |
737 | address. */ | |
738 | ||
3d6d86c6 | 739 | struct value * |
aa1ee363 | 740 | locate_var_value (struct symbol *var, struct frame_info *frame) |
c906108c SS |
741 | { |
742 | CORE_ADDR addr = 0; | |
743 | struct type *type = SYMBOL_TYPE (var); | |
3d6d86c6 | 744 | struct value *lazy_value; |
c906108c SS |
745 | |
746 | /* Evaluate it first; if the result is a memory address, we're fine. | |
747 | Lazy evaluation pays off here. */ | |
748 | ||
749 | lazy_value = read_var_value (var, frame); | |
750 | if (lazy_value == 0) | |
8a3fe4f8 | 751 | error (_("Address of \"%s\" is unknown."), SYMBOL_PRINT_NAME (var)); |
c906108c | 752 | |
d69fe07e | 753 | if (value_lazy (lazy_value) |
c906108c SS |
754 | || TYPE_CODE (type) == TYPE_CODE_FUNC) |
755 | { | |
3d6d86c6 | 756 | struct value *val; |
c906108c SS |
757 | |
758 | addr = VALUE_ADDRESS (lazy_value); | |
4478b372 | 759 | val = value_from_pointer (lookup_pointer_type (type), addr); |
c906108c SS |
760 | return val; |
761 | } | |
762 | ||
763 | /* Not a memory address; check what the problem was. */ | |
c5aa993b | 764 | switch (VALUE_LVAL (lazy_value)) |
c906108c SS |
765 | { |
766 | case lval_register: | |
9ee8fc9d AC |
767 | gdb_assert (REGISTER_NAME (VALUE_REGNUM (lazy_value)) != NULL |
768 | && *REGISTER_NAME (VALUE_REGNUM (lazy_value)) != '\0'); | |
8a3fe4f8 AC |
769 | error (_("Address requested for identifier " |
770 | "\"%s\" which is in register $%s"), | |
de5ad195 | 771 | SYMBOL_PRINT_NAME (var), |
9ee8fc9d | 772 | REGISTER_NAME (VALUE_REGNUM (lazy_value))); |
14e534aa PM |
773 | break; |
774 | ||
c906108c | 775 | default: |
8a3fe4f8 | 776 | error (_("Can't take address of \"%s\" which isn't an lvalue."), |
de5ad195 | 777 | SYMBOL_PRINT_NAME (var)); |
c906108c SS |
778 | break; |
779 | } | |
c5aa993b | 780 | return 0; /* For lint -- never reached */ |
c906108c | 781 | } |