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, | |
9564ee9f | 4 | 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2003, 2004 Free Software |
1bac305b | 5 | 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 |
37611a2b | 52 | extract_signed_integer (const void *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)) | |
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 | |
37611a2b | 86 | extract_unsigned_integer (const void *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)) | |
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 | |
66140c26 | 120 | extract_long_unsigned_integer (const void *addr, int orig_len, LONGEST *pval) |
c906108c SS |
121 | { |
122 | char *p, *first_addr; | |
123 | int len; | |
124 | ||
125 | len = orig_len; | |
d7449b42 | 126 | if (TARGET_BYTE_ORDER == BFD_ENDIAN_BIG) |
c906108c SS |
127 | { |
128 | for (p = (char *) addr; | |
129 | len > (int) sizeof (LONGEST) && p < (char *) addr + orig_len; | |
130 | p++) | |
131 | { | |
132 | if (*p == 0) | |
133 | len--; | |
134 | else | |
135 | break; | |
136 | } | |
137 | first_addr = p; | |
138 | } | |
139 | else | |
140 | { | |
141 | first_addr = (char *) addr; | |
142 | for (p = (char *) addr + orig_len - 1; | |
143 | len > (int) sizeof (LONGEST) && p >= (char *) addr; | |
144 | p--) | |
145 | { | |
146 | if (*p == 0) | |
147 | len--; | |
148 | else | |
149 | break; | |
150 | } | |
151 | } | |
152 | ||
153 | if (len <= (int) sizeof (LONGEST)) | |
154 | { | |
155 | *pval = (LONGEST) extract_unsigned_integer (first_addr, | |
156 | sizeof (LONGEST)); | |
157 | return 1; | |
158 | } | |
159 | ||
160 | return 0; | |
161 | } | |
162 | ||
4478b372 | 163 | |
4478b372 JB |
164 | /* Treat the bytes at BUF as a pointer of type TYPE, and return the |
165 | address it represents. */ | |
166 | CORE_ADDR | |
66140c26 | 167 | extract_typed_address (const void *buf, struct type *type) |
4478b372 JB |
168 | { |
169 | if (TYPE_CODE (type) != TYPE_CODE_PTR | |
170 | && TYPE_CODE (type) != TYPE_CODE_REF) | |
8e65ff28 AC |
171 | internal_error (__FILE__, __LINE__, |
172 | "extract_typed_address: " | |
4478b372 JB |
173 | "type is not a pointer or reference"); |
174 | ||
175 | return POINTER_TO_ADDRESS (type, buf); | |
176 | } | |
177 | ||
178 | ||
c906108c | 179 | void |
a9ac8f51 | 180 | store_signed_integer (void *addr, int len, LONGEST val) |
c906108c SS |
181 | { |
182 | unsigned char *p; | |
c5aa993b | 183 | unsigned char *startaddr = (unsigned char *) addr; |
c906108c SS |
184 | unsigned char *endaddr = startaddr + len; |
185 | ||
186 | /* Start at the least significant end of the integer, and work towards | |
187 | the most significant. */ | |
d7449b42 | 188 | if (TARGET_BYTE_ORDER == BFD_ENDIAN_BIG) |
c906108c SS |
189 | { |
190 | for (p = endaddr - 1; p >= startaddr; --p) | |
191 | { | |
192 | *p = val & 0xff; | |
193 | val >>= 8; | |
194 | } | |
195 | } | |
196 | else | |
197 | { | |
198 | for (p = startaddr; p < endaddr; ++p) | |
199 | { | |
200 | *p = val & 0xff; | |
201 | val >>= 8; | |
202 | } | |
203 | } | |
204 | } | |
205 | ||
206 | void | |
a9ac8f51 | 207 | store_unsigned_integer (void *addr, int len, ULONGEST val) |
c906108c SS |
208 | { |
209 | unsigned char *p; | |
c5aa993b | 210 | unsigned char *startaddr = (unsigned char *) addr; |
c906108c SS |
211 | unsigned char *endaddr = startaddr + len; |
212 | ||
213 | /* Start at the least significant end of the integer, and work towards | |
214 | the most significant. */ | |
d7449b42 | 215 | if (TARGET_BYTE_ORDER == BFD_ENDIAN_BIG) |
c906108c SS |
216 | { |
217 | for (p = endaddr - 1; p >= startaddr; --p) | |
218 | { | |
219 | *p = val & 0xff; | |
220 | val >>= 8; | |
221 | } | |
222 | } | |
223 | else | |
224 | { | |
225 | for (p = startaddr; p < endaddr; ++p) | |
226 | { | |
227 | *p = val & 0xff; | |
228 | val >>= 8; | |
229 | } | |
230 | } | |
231 | } | |
232 | ||
4478b372 JB |
233 | /* Store the address ADDR as a pointer of type TYPE at BUF, in target |
234 | form. */ | |
235 | void | |
236 | store_typed_address (void *buf, struct type *type, CORE_ADDR addr) | |
237 | { | |
238 | if (TYPE_CODE (type) != TYPE_CODE_PTR | |
239 | && TYPE_CODE (type) != TYPE_CODE_REF) | |
8e65ff28 AC |
240 | internal_error (__FILE__, __LINE__, |
241 | "store_typed_address: " | |
4478b372 JB |
242 | "type is not a pointer or reference"); |
243 | ||
244 | ADDRESS_TO_POINTER (type, buf, addr); | |
245 | } | |
246 | ||
247 | ||
248 | ||
376c9600 AC |
249 | /* Return a `value' with the contents of (virtual or cooked) register |
250 | REGNUM as found in the specified FRAME. The register's type is | |
7b83296f | 251 | determined by register_type(). |
c906108c | 252 | |
376c9600 AC |
253 | NOTE: returns NULL if register value is not available. Caller will |
254 | check return value or die! */ | |
c906108c | 255 | |
3d6d86c6 | 256 | struct value * |
376c9600 | 257 | value_of_register (int regnum, struct frame_info *frame) |
c906108c SS |
258 | { |
259 | CORE_ADDR addr; | |
260 | int optim; | |
3d6d86c6 | 261 | struct value *reg_val; |
ac2adee5 | 262 | int realnum; |
d9d9c31f | 263 | char raw_buffer[MAX_REGISTER_SIZE]; |
c906108c SS |
264 | enum lval_type lval; |
265 | ||
9564ee9f | 266 | /* User registers lie completely outside of the range of normal |
0406ec40 AC |
267 | registers. Catch them early so that the target never sees them. */ |
268 | if (regnum >= NUM_REGS + NUM_PSEUDO_REGS) | |
eb8bc282 | 269 | return value_of_user_reg (regnum, frame); |
0406ec40 | 270 | |
ac2adee5 | 271 | frame_register (frame, regnum, &optim, &lval, &addr, &realnum, raw_buffer); |
c906108c | 272 | |
c97dcfc7 AC |
273 | /* FIXME: cagney/2002-05-15: This test is just bogus. |
274 | ||
275 | It indicates that the target failed to supply a value for a | |
276 | register because it was "not available" at this time. Problem | |
277 | is, the target still has the register and so get saved_register() | |
278 | may be returning a value saved on the stack. */ | |
279 | ||
32178cab | 280 | if (register_cached (regnum) < 0) |
c5aa993b | 281 | return NULL; /* register value not available */ |
c906108c | 282 | |
7b83296f | 283 | reg_val = allocate_value (register_type (current_gdbarch, regnum)); |
c906108c | 284 | |
01e1877c AC |
285 | memcpy (VALUE_CONTENTS_RAW (reg_val), raw_buffer, |
286 | register_size (current_gdbarch, regnum)); | |
c906108c SS |
287 | VALUE_LVAL (reg_val) = lval; |
288 | VALUE_ADDRESS (reg_val) = addr; | |
9ee8fc9d | 289 | VALUE_REGNUM (reg_val) = regnum; |
c906108c SS |
290 | VALUE_OPTIMIZED_OUT (reg_val) = optim; |
291 | return reg_val; | |
292 | } | |
4478b372 JB |
293 | |
294 | /* Given a pointer of type TYPE in target form in BUF, return the | |
295 | address it represents. */ | |
296 | CORE_ADDR | |
66140c26 | 297 | unsigned_pointer_to_address (struct type *type, const void *buf) |
4478b372 | 298 | { |
af1342ab | 299 | return extract_unsigned_integer (buf, TYPE_LENGTH (type)); |
4478b372 JB |
300 | } |
301 | ||
ac2e2ef7 | 302 | CORE_ADDR |
66140c26 | 303 | signed_pointer_to_address (struct type *type, const void *buf) |
ac2e2ef7 AC |
304 | { |
305 | return extract_signed_integer (buf, TYPE_LENGTH (type)); | |
306 | } | |
4478b372 JB |
307 | |
308 | /* Given an address, store it as a pointer of type TYPE in target | |
309 | format in BUF. */ | |
310 | void | |
ac2e2ef7 | 311 | unsigned_address_to_pointer (struct type *type, void *buf, CORE_ADDR addr) |
4478b372 | 312 | { |
fbd9dcd3 | 313 | store_unsigned_integer (buf, TYPE_LENGTH (type), addr); |
4478b372 JB |
314 | } |
315 | ||
ac2e2ef7 AC |
316 | void |
317 | address_to_signed_pointer (struct type *type, void *buf, CORE_ADDR addr) | |
318 | { | |
319 | store_signed_integer (buf, TYPE_LENGTH (type), addr); | |
320 | } | |
c906108c SS |
321 | \f |
322 | /* Will calling read_var_value or locate_var_value on SYM end | |
323 | up caring what frame it is being evaluated relative to? SYM must | |
324 | be non-NULL. */ | |
325 | int | |
fba45db2 | 326 | symbol_read_needs_frame (struct symbol *sym) |
c906108c SS |
327 | { |
328 | switch (SYMBOL_CLASS (sym)) | |
329 | { | |
330 | /* All cases listed explicitly so that gcc -Wall will detect it if | |
c5aa993b | 331 | we failed to consider one. */ |
4c2df51b DJ |
332 | case LOC_COMPUTED: |
333 | case LOC_COMPUTED_ARG: | |
a67af2b9 AC |
334 | /* FIXME: cagney/2004-01-26: It should be possible to |
335 | unconditionally call the SYMBOL_OPS method when available. | |
d3efc286 | 336 | Unfortunately DWARF 2 stores the frame-base (instead of the |
a67af2b9 AC |
337 | function) location in a function's symbol. Oops! For the |
338 | moment enable this when/where applicable. */ | |
339 | return SYMBOL_OPS (sym)->read_needs_frame (sym); | |
4c2df51b | 340 | |
c906108c SS |
341 | case LOC_REGISTER: |
342 | case LOC_ARG: | |
343 | case LOC_REF_ARG: | |
344 | case LOC_REGPARM: | |
345 | case LOC_REGPARM_ADDR: | |
346 | case LOC_LOCAL: | |
347 | case LOC_LOCAL_ARG: | |
348 | case LOC_BASEREG: | |
349 | case LOC_BASEREG_ARG: | |
407caf07 | 350 | case LOC_HP_THREAD_LOCAL_STATIC: |
c906108c SS |
351 | return 1; |
352 | ||
353 | case LOC_UNDEF: | |
354 | case LOC_CONST: | |
355 | case LOC_STATIC: | |
356 | case LOC_INDIRECT: | |
357 | case LOC_TYPEDEF: | |
358 | ||
359 | case LOC_LABEL: | |
360 | /* Getting the address of a label can be done independently of the block, | |
c5aa993b JM |
361 | even if some *uses* of that address wouldn't work so well without |
362 | the right frame. */ | |
c906108c SS |
363 | |
364 | case LOC_BLOCK: | |
365 | case LOC_CONST_BYTES: | |
366 | case LOC_UNRESOLVED: | |
367 | case LOC_OPTIMIZED_OUT: | |
368 | return 0; | |
369 | } | |
370 | return 1; | |
371 | } | |
372 | ||
373 | /* Given a struct symbol for a variable, | |
374 | and a stack frame id, read the value of the variable | |
375 | and return a (pointer to a) struct value containing the value. | |
376 | If the variable cannot be found, return a zero pointer. | |
6e7f8b9c | 377 | If FRAME is NULL, use the deprecated_selected_frame. */ |
c906108c | 378 | |
3d6d86c6 | 379 | struct value * |
aa1ee363 | 380 | read_var_value (struct symbol *var, struct frame_info *frame) |
c906108c | 381 | { |
52f0bd74 | 382 | struct value *v; |
c906108c SS |
383 | struct type *type = SYMBOL_TYPE (var); |
384 | CORE_ADDR addr; | |
52f0bd74 | 385 | int len; |
c906108c SS |
386 | |
387 | v = allocate_value (type); | |
388 | VALUE_LVAL (v) = lval_memory; /* The most likely possibility. */ | |
c906108c SS |
389 | |
390 | len = TYPE_LENGTH (type); | |
391 | ||
7dd88986 DJ |
392 | |
393 | /* FIXME drow/2003-09-06: this call to the selected frame should be | |
394 | pushed upwards to the callers. */ | |
c5aa993b | 395 | if (frame == NULL) |
7dd88986 | 396 | frame = deprecated_safe_get_selected_frame (); |
c906108c SS |
397 | |
398 | switch (SYMBOL_CLASS (var)) | |
399 | { | |
400 | case LOC_CONST: | |
401 | /* Put the constant back in target format. */ | |
402 | store_signed_integer (VALUE_CONTENTS_RAW (v), len, | |
403 | (LONGEST) SYMBOL_VALUE (var)); | |
404 | VALUE_LVAL (v) = not_lval; | |
405 | return v; | |
406 | ||
407 | case LOC_LABEL: | |
408 | /* Put the constant back in target format. */ | |
409 | if (overlay_debugging) | |
4478b372 JB |
410 | { |
411 | CORE_ADDR addr | |
412 | = symbol_overlayed_address (SYMBOL_VALUE_ADDRESS (var), | |
413 | SYMBOL_BFD_SECTION (var)); | |
414 | store_typed_address (VALUE_CONTENTS_RAW (v), type, addr); | |
415 | } | |
c906108c | 416 | else |
4478b372 JB |
417 | store_typed_address (VALUE_CONTENTS_RAW (v), type, |
418 | SYMBOL_VALUE_ADDRESS (var)); | |
c906108c SS |
419 | VALUE_LVAL (v) = not_lval; |
420 | return v; | |
421 | ||
422 | case LOC_CONST_BYTES: | |
423 | { | |
424 | char *bytes_addr; | |
425 | bytes_addr = SYMBOL_VALUE_BYTES (var); | |
426 | memcpy (VALUE_CONTENTS_RAW (v), bytes_addr, len); | |
427 | VALUE_LVAL (v) = not_lval; | |
428 | return v; | |
429 | } | |
430 | ||
431 | case LOC_STATIC: | |
432 | if (overlay_debugging) | |
433 | addr = symbol_overlayed_address (SYMBOL_VALUE_ADDRESS (var), | |
434 | SYMBOL_BFD_SECTION (var)); | |
435 | else | |
436 | addr = SYMBOL_VALUE_ADDRESS (var); | |
437 | break; | |
438 | ||
439 | case LOC_INDIRECT: | |
f76febae AC |
440 | { |
441 | /* The import slot does not have a real address in it from the | |
442 | dynamic loader (dld.sl on HP-UX), if the target hasn't | |
443 | begun execution yet, so check for that. */ | |
444 | CORE_ADDR locaddr; | |
445 | struct value *loc; | |
446 | if (!target_has_execution) | |
447 | error ("\ | |
c906108c SS |
448 | Attempt to access variable defined in different shared object or load module when\n\ |
449 | addresses have not been bound by the dynamic loader. Try again when executable is running."); | |
c5aa993b | 450 | |
f76febae | 451 | locaddr = SYMBOL_VALUE_ADDRESS (var); |
00a4c844 | 452 | loc = value_at (lookup_pointer_type (type), locaddr); |
1aa20aa8 | 453 | addr = value_as_address (loc); |
f76febae | 454 | } |
c906108c SS |
455 | |
456 | case LOC_ARG: | |
457 | if (frame == NULL) | |
458 | return 0; | |
da62e633 | 459 | addr = get_frame_args_address (frame); |
c906108c SS |
460 | if (!addr) |
461 | return 0; | |
462 | addr += SYMBOL_VALUE (var); | |
463 | break; | |
464 | ||
465 | case LOC_REF_ARG: | |
f76febae AC |
466 | { |
467 | struct value *ref; | |
468 | CORE_ADDR argref; | |
469 | if (frame == NULL) | |
470 | return 0; | |
da62e633 | 471 | argref = get_frame_args_address (frame); |
f76febae AC |
472 | if (!argref) |
473 | return 0; | |
474 | argref += SYMBOL_VALUE (var); | |
00a4c844 | 475 | ref = value_at (lookup_pointer_type (type), argref); |
1aa20aa8 | 476 | addr = value_as_address (ref); |
f76febae AC |
477 | break; |
478 | } | |
c906108c SS |
479 | |
480 | case LOC_LOCAL: | |
481 | case LOC_LOCAL_ARG: | |
482 | if (frame == NULL) | |
483 | return 0; | |
da62e633 | 484 | addr = get_frame_locals_address (frame); |
c906108c SS |
485 | addr += SYMBOL_VALUE (var); |
486 | break; | |
487 | ||
488 | case LOC_BASEREG: | |
489 | case LOC_BASEREG_ARG: | |
407caf07 | 490 | case LOC_HP_THREAD_LOCAL_STATIC: |
c906108c | 491 | { |
3d6d86c6 | 492 | struct value *regval; |
c5aa993b | 493 | |
9ed10b08 ND |
494 | regval = value_from_register (lookup_pointer_type (type), |
495 | SYMBOL_BASEREG (var), frame); | |
496 | if (regval == NULL) | |
497 | error ("Value of base register not available."); | |
1aa20aa8 | 498 | addr = value_as_address (regval); |
c5aa993b JM |
499 | addr += SYMBOL_VALUE (var); |
500 | break; | |
c906108c | 501 | } |
c5aa993b | 502 | |
c906108c SS |
503 | case LOC_TYPEDEF: |
504 | error ("Cannot look up value of a typedef"); | |
505 | break; | |
506 | ||
507 | case LOC_BLOCK: | |
508 | if (overlay_debugging) | |
c5aa993b | 509 | VALUE_ADDRESS (v) = symbol_overlayed_address |
c906108c SS |
510 | (BLOCK_START (SYMBOL_BLOCK_VALUE (var)), SYMBOL_BFD_SECTION (var)); |
511 | else | |
512 | VALUE_ADDRESS (v) = BLOCK_START (SYMBOL_BLOCK_VALUE (var)); | |
513 | return v; | |
514 | ||
515 | case LOC_REGISTER: | |
516 | case LOC_REGPARM: | |
517 | case LOC_REGPARM_ADDR: | |
518 | { | |
519 | struct block *b; | |
520 | int regno = SYMBOL_VALUE (var); | |
3d6d86c6 | 521 | struct value *regval; |
c906108c SS |
522 | |
523 | if (frame == NULL) | |
524 | return 0; | |
ae767bfb | 525 | b = get_frame_block (frame, 0); |
c906108c SS |
526 | |
527 | if (SYMBOL_CLASS (var) == LOC_REGPARM_ADDR) | |
528 | { | |
529 | regval = value_from_register (lookup_pointer_type (type), | |
c5aa993b | 530 | regno, |
c906108c SS |
531 | frame); |
532 | ||
533 | if (regval == NULL) | |
534 | error ("Value of register variable not available."); | |
535 | ||
1aa20aa8 | 536 | addr = value_as_address (regval); |
c906108c SS |
537 | VALUE_LVAL (v) = lval_memory; |
538 | } | |
539 | else | |
540 | { | |
541 | regval = value_from_register (type, regno, frame); | |
542 | ||
543 | if (regval == NULL) | |
544 | error ("Value of register variable not available."); | |
545 | return regval; | |
546 | } | |
547 | } | |
548 | break; | |
549 | ||
4c2df51b DJ |
550 | case LOC_COMPUTED: |
551 | case LOC_COMPUTED_ARG: | |
a67af2b9 AC |
552 | /* FIXME: cagney/2004-01-26: It should be possible to |
553 | unconditionally call the SYMBOL_OPS method when available. | |
d3efc286 | 554 | Unfortunately DWARF 2 stores the frame-base (instead of the |
a67af2b9 AC |
555 | function) location in a function's symbol. Oops! For the |
556 | moment enable this when/where applicable. */ | |
557 | if (frame == 0 && SYMBOL_OPS (var)->read_needs_frame (var)) | |
558 | return 0; | |
559 | return SYMBOL_OPS (var)->read_variable (var, frame); | |
4c2df51b | 560 | |
c906108c SS |
561 | case LOC_UNRESOLVED: |
562 | { | |
563 | struct minimal_symbol *msym; | |
564 | ||
22abf04a | 565 | msym = lookup_minimal_symbol (DEPRECATED_SYMBOL_NAME (var), NULL, NULL); |
c906108c SS |
566 | if (msym == NULL) |
567 | return 0; | |
568 | if (overlay_debugging) | |
569 | addr = symbol_overlayed_address (SYMBOL_VALUE_ADDRESS (msym), | |
570 | SYMBOL_BFD_SECTION (msym)); | |
571 | else | |
572 | addr = SYMBOL_VALUE_ADDRESS (msym); | |
573 | } | |
574 | break; | |
575 | ||
576 | case LOC_OPTIMIZED_OUT: | |
577 | VALUE_LVAL (v) = not_lval; | |
578 | VALUE_OPTIMIZED_OUT (v) = 1; | |
579 | return v; | |
580 | ||
581 | default: | |
582 | error ("Cannot look up value of a botched symbol."); | |
583 | break; | |
584 | } | |
585 | ||
586 | VALUE_ADDRESS (v) = addr; | |
587 | VALUE_LAZY (v) = 1; | |
588 | return v; | |
589 | } | |
590 | ||
591 | /* Return a value of type TYPE, stored in register REGNUM, in frame | |
0f2c5ba5 | 592 | FRAME. |
c906108c SS |
593 | |
594 | NOTE: returns NULL if register value is not available. | |
595 | Caller will check return value or die! */ | |
596 | ||
3d6d86c6 | 597 | struct value * |
fba45db2 | 598 | value_from_register (struct type *type, int regnum, struct frame_info *frame) |
c906108c | 599 | { |
ff2e87ac | 600 | struct gdbarch *gdbarch = get_frame_arch (frame); |
3d6d86c6 | 601 | struct value *v = allocate_value (type); |
c906108c | 602 | CHECK_TYPEDEF (type); |
c906108c | 603 | |
4589a601 JB |
604 | if (TYPE_LENGTH (type) == 0) |
605 | { | |
606 | /* It doesn't matter much what we return for this: since the | |
607 | length is zero, it could be anything. But if allowed to see | |
608 | a zero-length type, the register-finding loop below will set | |
609 | neither mem_stor nor reg_stor, and then report an internal | |
610 | error. | |
611 | ||
612 | Zero-length types can legitimately arise from declarations | |
f98c22d5 JB |
613 | like 'struct {}' (a GCC extension, not valid ISO C). GDB may |
614 | also create them when it finds bogus debugging information; | |
615 | for example, in GCC 2.95.4 and binutils 2.11.93.0.2, the | |
616 | STABS BINCL->EXCL compression process can create bad type | |
617 | numbers. GDB reads these as TYPE_CODE_UNDEF types, with zero | |
618 | length. (That bug is actually the only known way to get a | |
619 | zero-length value allocated to a register --- which is what | |
620 | it takes to make it here.) | |
4589a601 JB |
621 | |
622 | We'll just attribute the value to the original register. */ | |
623 | VALUE_LVAL (v) = lval_register; | |
624 | VALUE_ADDRESS (v) = regnum; | |
9ee8fc9d | 625 | VALUE_REGNUM (v) = regnum; |
4589a601 JB |
626 | } |
627 | else if (CONVERT_REGISTER_P (regnum, type)) | |
ff2e87ac AC |
628 | { |
629 | /* The ISA/ABI need to something weird when obtaining the | |
630 | specified value from this register. It might need to | |
631 | re-order non-adjacent, starting with REGNUM (see MIPS and | |
632 | i386). It might need to convert the [float] register into | |
633 | the corresponding [integer] type (see Alpha). The assumption | |
634 | is that REGISTER_TO_VALUE populates the entire value | |
635 | including the location. */ | |
636 | REGISTER_TO_VALUE (frame, regnum, type, VALUE_CONTENTS_RAW (v)); | |
25ae5d16 | 637 | VALUE_LVAL (v) = lval_register; |
ff2e87ac | 638 | VALUE_FRAME_ID (v) = get_frame_id (frame); |
9ee8fc9d | 639 | VALUE_REGNUM (v) = regnum; |
ff2e87ac AC |
640 | } |
641 | else | |
c906108c | 642 | { |
c906108c SS |
643 | int local_regnum; |
644 | int mem_stor = 0, reg_stor = 0; | |
645 | int mem_tracking = 1; | |
646 | CORE_ADDR last_addr = 0; | |
647 | CORE_ADDR first_addr = 0; | |
ff2e87ac AC |
648 | int first_realnum = regnum; |
649 | int len = TYPE_LENGTH (type); | |
650 | int value_bytes_copied; | |
651 | int optimized = 0; | |
652 | char *value_bytes = (char *) alloca (len + MAX_REGISTER_SIZE); | |
c906108c SS |
653 | |
654 | /* Copy all of the data out, whereever it may be. */ | |
ff2e87ac AC |
655 | for (local_regnum = regnum, value_bytes_copied = 0; |
656 | value_bytes_copied < len; | |
3acba339 | 657 | (value_bytes_copied += register_size (current_gdbarch, local_regnum), |
ff2e87ac AC |
658 | ++local_regnum)) |
659 | { | |
660 | int realnum; | |
661 | int optim; | |
662 | enum lval_type lval; | |
663 | CORE_ADDR addr; | |
664 | frame_register (frame, local_regnum, &optim, &lval, &addr, | |
665 | &realnum, value_bytes + value_bytes_copied); | |
666 | optimized += optim; | |
667 | if (register_cached (local_regnum) == -1) | |
668 | return NULL; /* register value not available */ | |
669 | ||
670 | if (regnum == local_regnum) | |
671 | { | |
c906108c | 672 | first_addr = addr; |
ff2e87ac AC |
673 | first_realnum = realnum; |
674 | } | |
675 | if (lval == lval_register) | |
676 | reg_stor++; | |
677 | else | |
678 | { | |
679 | mem_stor++; | |
680 | ||
25ae5d16 AC |
681 | /* FIXME: cagney/2004-11-12: I think this is trying to |
682 | check that the stored registers are adjacent in | |
683 | memory. It isn't doing a good job? */ | |
ff2e87ac AC |
684 | mem_tracking = (mem_tracking |
685 | && (regnum == local_regnum | |
686 | || addr == last_addr)); | |
687 | } | |
688 | last_addr = addr; | |
689 | } | |
690 | ||
25ae5d16 | 691 | if (mem_tracking && mem_stor && !reg_stor) |
c906108c SS |
692 | { |
693 | VALUE_LVAL (v) = lval_memory; | |
694 | VALUE_ADDRESS (v) = first_addr; | |
695 | } | |
25ae5d16 | 696 | else |
c906108c SS |
697 | { |
698 | VALUE_LVAL (v) = lval_register; | |
25ae5d16 AC |
699 | VALUE_FRAME_ID (v) = get_frame_id (frame); |
700 | VALUE_REGNUM (v) = regnum; | |
c906108c | 701 | } |
ff2e87ac AC |
702 | |
703 | VALUE_OPTIMIZED_OUT (v) = optimized; | |
704 | ||
c906108c | 705 | /* Any structure stored in more than one register will always be |
ff2e87ac | 706 | an integral number of registers. Otherwise, you need to do |
c5aa993b JM |
707 | some fiddling with the last register copied here for little |
708 | endian machines. */ | |
ff2e87ac | 709 | if (TARGET_BYTE_ORDER == BFD_ENDIAN_BIG |
3acba339 | 710 | && len < register_size (current_gdbarch, regnum)) |
ff2e87ac | 711 | /* Big-endian, and we want less than full size. */ |
df407dfe | 712 | v->offset = register_size (current_gdbarch, regnum) - len; |
ff2e87ac | 713 | else |
df407dfe AC |
714 | v->offset = 0; |
715 | memcpy (VALUE_CONTENTS_RAW (v), value_bytes + value_offset (v), len); | |
c906108c | 716 | } |
c906108c SS |
717 | return v; |
718 | } | |
ff2e87ac | 719 | |
c906108c SS |
720 | \f |
721 | /* Given a struct symbol for a variable or function, | |
722 | and a stack frame id, | |
723 | return a (pointer to a) struct value containing the properly typed | |
724 | address. */ | |
725 | ||
3d6d86c6 | 726 | struct value * |
aa1ee363 | 727 | locate_var_value (struct symbol *var, struct frame_info *frame) |
c906108c SS |
728 | { |
729 | CORE_ADDR addr = 0; | |
730 | struct type *type = SYMBOL_TYPE (var); | |
3d6d86c6 | 731 | struct value *lazy_value; |
c906108c SS |
732 | |
733 | /* Evaluate it first; if the result is a memory address, we're fine. | |
734 | Lazy evaluation pays off here. */ | |
735 | ||
736 | lazy_value = read_var_value (var, frame); | |
737 | if (lazy_value == 0) | |
de5ad195 | 738 | error ("Address of \"%s\" is unknown.", SYMBOL_PRINT_NAME (var)); |
c906108c SS |
739 | |
740 | if (VALUE_LAZY (lazy_value) | |
741 | || TYPE_CODE (type) == TYPE_CODE_FUNC) | |
742 | { | |
3d6d86c6 | 743 | struct value *val; |
c906108c SS |
744 | |
745 | addr = VALUE_ADDRESS (lazy_value); | |
4478b372 | 746 | val = value_from_pointer (lookup_pointer_type (type), addr); |
c906108c SS |
747 | return val; |
748 | } | |
749 | ||
750 | /* Not a memory address; check what the problem was. */ | |
c5aa993b | 751 | switch (VALUE_LVAL (lazy_value)) |
c906108c SS |
752 | { |
753 | case lval_register: | |
9ee8fc9d AC |
754 | gdb_assert (REGISTER_NAME (VALUE_REGNUM (lazy_value)) != NULL |
755 | && *REGISTER_NAME (VALUE_REGNUM (lazy_value)) != '\0'); | |
14e534aa PM |
756 | error("Address requested for identifier " |
757 | "\"%s\" which is in register $%s", | |
de5ad195 | 758 | SYMBOL_PRINT_NAME (var), |
9ee8fc9d | 759 | REGISTER_NAME (VALUE_REGNUM (lazy_value))); |
14e534aa PM |
760 | break; |
761 | ||
c906108c SS |
762 | default: |
763 | error ("Can't take address of \"%s\" which isn't an lvalue.", | |
de5ad195 | 764 | SYMBOL_PRINT_NAME (var)); |
c906108c SS |
765 | break; |
766 | } | |
c5aa993b | 767 | return 0; /* For lint -- never reached */ |
c906108c | 768 | } |