Commit | Line | Data |
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c906108c | 1 | /* Find a variable's value in memory, for GDB, the GNU debugger. |
1bac305b | 2 | |
61baf725 | 3 | Copyright (C) 1986-2017 Free Software Foundation, Inc. |
c906108c | 4 | |
c5aa993b | 5 | This file is part of GDB. |
c906108c | 6 | |
c5aa993b JM |
7 | This program is free software; you can redistribute it and/or modify |
8 | it under the terms of the GNU General Public License as published by | |
a9762ec7 | 9 | the Free Software Foundation; either version 3 of the License, or |
c5aa993b | 10 | (at your option) any later version. |
c906108c | 11 | |
c5aa993b JM |
12 | This program is distributed in the hope that it will be useful, |
13 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
14 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
15 | GNU General Public License for more details. | |
c906108c | 16 | |
c5aa993b | 17 | You should have received a copy of the GNU General Public License |
a9762ec7 | 18 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ |
c906108c SS |
19 | |
20 | #include "defs.h" | |
21 | #include "symtab.h" | |
22 | #include "gdbtypes.h" | |
23 | #include "frame.h" | |
24 | #include "value.h" | |
25 | #include "gdbcore.h" | |
26 | #include "inferior.h" | |
27 | #include "target.h" | |
c906108c | 28 | #include "floatformat.h" |
c5aa993b | 29 | #include "symfile.h" /* for overlay functions */ |
4e052eda | 30 | #include "regcache.h" |
eb8bc282 | 31 | #include "user-regs.h" |
fe898f56 | 32 | #include "block.h" |
e0740f77 | 33 | #include "objfiles.h" |
a5ee536b | 34 | #include "language.h" |
63e43d3a | 35 | #include "dwarf2loc.h" |
c906108c | 36 | |
9659616a MS |
37 | /* Basic byte-swapping routines. All 'extract' functions return a |
38 | host-format integer from a target-format integer at ADDR which is | |
39 | LEN bytes long. */ | |
c906108c SS |
40 | |
41 | #if TARGET_CHAR_BIT != 8 || HOST_CHAR_BIT != 8 | |
42 | /* 8 bit characters are a pretty safe assumption these days, so we | |
43 | assume it throughout all these swapping routines. If we had to deal with | |
44 | 9 bit characters, we would need to make len be in bits and would have | |
45 | to re-write these routines... */ | |
c5aa993b | 46 | you lose |
c906108c SS |
47 | #endif |
48 | ||
a9ac8f51 | 49 | LONGEST |
e17a4113 UW |
50 | extract_signed_integer (const gdb_byte *addr, int len, |
51 | enum bfd_endian byte_order) | |
c906108c SS |
52 | { |
53 | LONGEST retval; | |
37611a2b AC |
54 | const unsigned char *p; |
55 | const unsigned char *startaddr = addr; | |
56 | const unsigned char *endaddr = startaddr + len; | |
c906108c SS |
57 | |
58 | if (len > (int) sizeof (LONGEST)) | |
8a3fe4f8 AC |
59 | error (_("\ |
60 | That operation is not available on integers of more than %d bytes."), | |
baa6f10b | 61 | (int) sizeof (LONGEST)); |
c906108c SS |
62 | |
63 | /* Start at the most significant end of the integer, and work towards | |
64 | the least significant. */ | |
e17a4113 | 65 | if (byte_order == BFD_ENDIAN_BIG) |
c906108c SS |
66 | { |
67 | p = startaddr; | |
68 | /* Do the sign extension once at the start. */ | |
c5aa993b | 69 | retval = ((LONGEST) * p ^ 0x80) - 0x80; |
c906108c SS |
70 | for (++p; p < endaddr; ++p) |
71 | retval = (retval << 8) | *p; | |
72 | } | |
73 | else | |
74 | { | |
75 | p = endaddr - 1; | |
76 | /* Do the sign extension once at the start. */ | |
c5aa993b | 77 | retval = ((LONGEST) * p ^ 0x80) - 0x80; |
c906108c SS |
78 | for (--p; p >= startaddr; --p) |
79 | retval = (retval << 8) | *p; | |
80 | } | |
81 | return retval; | |
82 | } | |
83 | ||
84 | ULONGEST | |
e17a4113 UW |
85 | extract_unsigned_integer (const gdb_byte *addr, int len, |
86 | enum bfd_endian byte_order) | |
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; | |
e17a4113 | 101 | if (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 | 120 | extract_long_unsigned_integer (const gdb_byte *addr, int orig_len, |
e17a4113 | 121 | enum bfd_endian byte_order, 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; | |
e17a4113 | 128 | if (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, | |
e17a4113 UW |
158 | sizeof (LONGEST), |
159 | byte_order); | |
c906108c SS |
160 | return 1; |
161 | } | |
162 | ||
163 | return 0; | |
164 | } | |
165 | ||
4478b372 | 166 | |
4478b372 JB |
167 | /* Treat the bytes at BUF as a pointer of type TYPE, and return the |
168 | address it represents. */ | |
169 | CORE_ADDR | |
0d509538 | 170 | extract_typed_address (const gdb_byte *buf, struct type *type) |
4478b372 JB |
171 | { |
172 | if (TYPE_CODE (type) != TYPE_CODE_PTR | |
173 | && TYPE_CODE (type) != TYPE_CODE_REF) | |
8e65ff28 | 174 | internal_error (__FILE__, __LINE__, |
e2e0b3e5 AC |
175 | _("extract_typed_address: " |
176 | "type is not a pointer or reference")); | |
4478b372 | 177 | |
50810684 | 178 | return gdbarch_pointer_to_address (get_type_arch (type), type, buf); |
4478b372 JB |
179 | } |
180 | ||
9659616a MS |
181 | /* All 'store' functions accept a host-format integer and store a |
182 | target-format integer at ADDR which is LEN bytes long. */ | |
4478b372 | 183 | |
c906108c | 184 | void |
e17a4113 UW |
185 | store_signed_integer (gdb_byte *addr, int len, |
186 | enum bfd_endian byte_order, LONGEST val) | |
c906108c | 187 | { |
0d509538 AC |
188 | gdb_byte *p; |
189 | gdb_byte *startaddr = addr; | |
190 | gdb_byte *endaddr = startaddr + len; | |
c906108c SS |
191 | |
192 | /* Start at the least significant end of the integer, and work towards | |
193 | the most significant. */ | |
e17a4113 | 194 | if (byte_order == BFD_ENDIAN_BIG) |
c906108c SS |
195 | { |
196 | for (p = endaddr - 1; p >= startaddr; --p) | |
197 | { | |
198 | *p = val & 0xff; | |
199 | val >>= 8; | |
200 | } | |
201 | } | |
202 | else | |
203 | { | |
204 | for (p = startaddr; p < endaddr; ++p) | |
205 | { | |
206 | *p = val & 0xff; | |
207 | val >>= 8; | |
208 | } | |
209 | } | |
210 | } | |
211 | ||
212 | void | |
e17a4113 UW |
213 | store_unsigned_integer (gdb_byte *addr, int len, |
214 | enum bfd_endian byte_order, ULONGEST val) | |
c906108c SS |
215 | { |
216 | unsigned char *p; | |
c5aa993b | 217 | unsigned char *startaddr = (unsigned char *) addr; |
c906108c SS |
218 | unsigned char *endaddr = startaddr + len; |
219 | ||
220 | /* Start at the least significant end of the integer, and work towards | |
221 | the most significant. */ | |
e17a4113 | 222 | if (byte_order == BFD_ENDIAN_BIG) |
c906108c SS |
223 | { |
224 | for (p = endaddr - 1; p >= startaddr; --p) | |
225 | { | |
226 | *p = val & 0xff; | |
227 | val >>= 8; | |
228 | } | |
229 | } | |
230 | else | |
231 | { | |
232 | for (p = startaddr; p < endaddr; ++p) | |
233 | { | |
234 | *p = val & 0xff; | |
235 | val >>= 8; | |
236 | } | |
237 | } | |
238 | } | |
239 | ||
4478b372 JB |
240 | /* Store the address ADDR as a pointer of type TYPE at BUF, in target |
241 | form. */ | |
242 | void | |
0d509538 | 243 | store_typed_address (gdb_byte *buf, struct type *type, CORE_ADDR addr) |
4478b372 JB |
244 | { |
245 | if (TYPE_CODE (type) != TYPE_CODE_PTR | |
246 | && TYPE_CODE (type) != TYPE_CODE_REF) | |
8e65ff28 | 247 | internal_error (__FILE__, __LINE__, |
e2e0b3e5 AC |
248 | _("store_typed_address: " |
249 | "type is not a pointer or reference")); | |
4478b372 | 250 | |
50810684 | 251 | gdbarch_address_to_pointer (get_type_arch (type), type, buf, addr); |
4478b372 JB |
252 | } |
253 | ||
254 | ||
255 | ||
376c9600 AC |
256 | /* Return a `value' with the contents of (virtual or cooked) register |
257 | REGNUM as found in the specified FRAME. The register's type is | |
9c5ea4d9 | 258 | determined by register_type(). */ |
c906108c | 259 | |
3d6d86c6 | 260 | struct value * |
376c9600 | 261 | value_of_register (int regnum, struct frame_info *frame) |
c906108c | 262 | { |
e9e45075 | 263 | struct gdbarch *gdbarch = get_frame_arch (frame); |
3d6d86c6 | 264 | struct value *reg_val; |
c906108c | 265 | |
9564ee9f | 266 | /* User registers lie completely outside of the range of normal |
0406ec40 | 267 | registers. Catch them early so that the target never sees them. */ |
e9e45075 UW |
268 | if (regnum >= gdbarch_num_regs (gdbarch) |
269 | + gdbarch_num_pseudo_regs (gdbarch)) | |
eb8bc282 | 270 | return value_of_user_reg (regnum, frame); |
0406ec40 | 271 | |
d5b495b4 PA |
272 | reg_val = value_of_register_lazy (frame, regnum); |
273 | value_fetch_lazy (reg_val); | |
c906108c SS |
274 | return reg_val; |
275 | } | |
4478b372 | 276 | |
9214ee5f DJ |
277 | /* Return a `value' with the contents of (virtual or cooked) register |
278 | REGNUM as found in the specified FRAME. The register's type is | |
279 | determined by register_type(). The value is not fetched. */ | |
280 | ||
281 | struct value * | |
282 | value_of_register_lazy (struct frame_info *frame, int regnum) | |
283 | { | |
284 | struct gdbarch *gdbarch = get_frame_arch (frame); | |
285 | struct value *reg_val; | |
41b56feb | 286 | struct frame_info *next_frame; |
9214ee5f DJ |
287 | |
288 | gdb_assert (regnum < (gdbarch_num_regs (gdbarch) | |
289 | + gdbarch_num_pseudo_regs (gdbarch))); | |
290 | ||
41b56feb KB |
291 | gdb_assert (frame != NULL); |
292 | ||
293 | next_frame = get_next_frame_sentinel_okay (frame); | |
294 | ||
295 | /* We should have a valid next frame. */ | |
296 | gdb_assert (frame_id_p (get_frame_id (next_frame))); | |
9214ee5f | 297 | |
41e8491f | 298 | reg_val = allocate_value_lazy (register_type (gdbarch, regnum)); |
9214ee5f DJ |
299 | VALUE_LVAL (reg_val) = lval_register; |
300 | VALUE_REGNUM (reg_val) = regnum; | |
41b56feb KB |
301 | VALUE_NEXT_FRAME_ID (reg_val) = get_frame_id (next_frame); |
302 | ||
9214ee5f DJ |
303 | return reg_val; |
304 | } | |
305 | ||
4478b372 JB |
306 | /* Given a pointer of type TYPE in target form in BUF, return the |
307 | address it represents. */ | |
308 | CORE_ADDR | |
9898f801 UW |
309 | unsigned_pointer_to_address (struct gdbarch *gdbarch, |
310 | struct type *type, const gdb_byte *buf) | |
4478b372 | 311 | { |
e17a4113 | 312 | enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); |
bb9bcb69 | 313 | |
e17a4113 | 314 | return extract_unsigned_integer (buf, TYPE_LENGTH (type), byte_order); |
4478b372 JB |
315 | } |
316 | ||
ac2e2ef7 | 317 | CORE_ADDR |
9898f801 UW |
318 | signed_pointer_to_address (struct gdbarch *gdbarch, |
319 | struct type *type, const gdb_byte *buf) | |
ac2e2ef7 | 320 | { |
e17a4113 | 321 | enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); |
bb9bcb69 | 322 | |
e17a4113 | 323 | return extract_signed_integer (buf, TYPE_LENGTH (type), byte_order); |
ac2e2ef7 | 324 | } |
4478b372 JB |
325 | |
326 | /* Given an address, store it as a pointer of type TYPE in target | |
327 | format in BUF. */ | |
328 | void | |
9898f801 UW |
329 | unsigned_address_to_pointer (struct gdbarch *gdbarch, struct type *type, |
330 | gdb_byte *buf, CORE_ADDR addr) | |
4478b372 | 331 | { |
e17a4113 | 332 | enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); |
bb9bcb69 | 333 | |
e17a4113 | 334 | store_unsigned_integer (buf, TYPE_LENGTH (type), byte_order, addr); |
4478b372 JB |
335 | } |
336 | ||
ac2e2ef7 | 337 | void |
9898f801 UW |
338 | address_to_signed_pointer (struct gdbarch *gdbarch, struct type *type, |
339 | gdb_byte *buf, CORE_ADDR addr) | |
ac2e2ef7 | 340 | { |
e17a4113 | 341 | enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); |
bb9bcb69 | 342 | |
e17a4113 | 343 | store_signed_integer (buf, TYPE_LENGTH (type), byte_order, addr); |
ac2e2ef7 | 344 | } |
c906108c | 345 | \f |
0b31a4bc TT |
346 | /* See value.h. */ |
347 | ||
348 | enum symbol_needs_kind | |
349 | symbol_read_needs (struct symbol *sym) | |
c906108c | 350 | { |
24d6c2a0 | 351 | if (SYMBOL_COMPUTED_OPS (sym) != NULL) |
0b31a4bc | 352 | return SYMBOL_COMPUTED_OPS (sym)->get_symbol_read_needs (sym); |
24d6c2a0 | 353 | |
c906108c SS |
354 | switch (SYMBOL_CLASS (sym)) |
355 | { | |
356 | /* All cases listed explicitly so that gcc -Wall will detect it if | |
c5aa993b | 357 | we failed to consider one. */ |
4c2df51b | 358 | case LOC_COMPUTED: |
24d6c2a0 | 359 | gdb_assert_not_reached (_("LOC_COMPUTED variable missing a method")); |
4c2df51b | 360 | |
c906108c SS |
361 | case LOC_REGISTER: |
362 | case LOC_ARG: | |
363 | case LOC_REF_ARG: | |
c906108c SS |
364 | case LOC_REGPARM_ADDR: |
365 | case LOC_LOCAL: | |
0b31a4bc | 366 | return SYMBOL_NEEDS_FRAME; |
c906108c SS |
367 | |
368 | case LOC_UNDEF: | |
369 | case LOC_CONST: | |
370 | case LOC_STATIC: | |
c906108c SS |
371 | case LOC_TYPEDEF: |
372 | ||
373 | case LOC_LABEL: | |
374 | /* Getting the address of a label can be done independently of the block, | |
c5aa993b JM |
375 | even if some *uses* of that address wouldn't work so well without |
376 | the right frame. */ | |
c906108c SS |
377 | |
378 | case LOC_BLOCK: | |
379 | case LOC_CONST_BYTES: | |
380 | case LOC_UNRESOLVED: | |
381 | case LOC_OPTIMIZED_OUT: | |
0b31a4bc | 382 | return SYMBOL_NEEDS_NONE; |
c906108c | 383 | } |
0b31a4bc TT |
384 | return SYMBOL_NEEDS_FRAME; |
385 | } | |
386 | ||
387 | /* See value.h. */ | |
388 | ||
389 | int | |
390 | symbol_read_needs_frame (struct symbol *sym) | |
391 | { | |
392 | return symbol_read_needs (sym) == SYMBOL_NEEDS_FRAME; | |
c906108c SS |
393 | } |
394 | ||
19630284 JB |
395 | /* Private data to be used with minsym_lookup_iterator_cb. */ |
396 | ||
397 | struct minsym_lookup_data | |
398 | { | |
399 | /* The name of the minimal symbol we are searching for. */ | |
400 | const char *name; | |
401 | ||
402 | /* The field where the callback should store the minimal symbol | |
403 | if found. It should be initialized to NULL before the search | |
404 | is started. */ | |
3b7344d5 | 405 | struct bound_minimal_symbol result; |
19630284 JB |
406 | }; |
407 | ||
408 | /* A callback function for gdbarch_iterate_over_objfiles_in_search_order. | |
409 | It searches by name for a minimal symbol within the given OBJFILE. | |
410 | The arguments are passed via CB_DATA, which in reality is a pointer | |
411 | to struct minsym_lookup_data. */ | |
412 | ||
413 | static int | |
414 | minsym_lookup_iterator_cb (struct objfile *objfile, void *cb_data) | |
415 | { | |
416 | struct minsym_lookup_data *data = (struct minsym_lookup_data *) cb_data; | |
417 | ||
3b7344d5 | 418 | gdb_assert (data->result.minsym == NULL); |
19630284 JB |
419 | |
420 | data->result = lookup_minimal_symbol (data->name, NULL, objfile); | |
421 | ||
422 | /* The iterator should stop iff a match was found. */ | |
3b7344d5 | 423 | return (data->result.minsym != NULL); |
19630284 JB |
424 | } |
425 | ||
63e43d3a PMR |
426 | /* Given static link expression and the frame it lives in, look for the frame |
427 | the static links points to and return it. Return NULL if we could not find | |
428 | such a frame. */ | |
429 | ||
430 | static struct frame_info * | |
431 | follow_static_link (struct frame_info *frame, | |
432 | const struct dynamic_prop *static_link) | |
433 | { | |
434 | CORE_ADDR upper_frame_base; | |
435 | ||
436 | if (!dwarf2_evaluate_property (static_link, frame, NULL, &upper_frame_base)) | |
437 | return NULL; | |
438 | ||
439 | /* Now climb up the stack frame until we reach the frame we are interested | |
440 | in. */ | |
441 | for (; frame != NULL; frame = get_prev_frame (frame)) | |
442 | { | |
443 | struct symbol *framefunc = get_frame_function (frame); | |
444 | ||
445 | /* Stacks can be quite deep: give the user a chance to stop this. */ | |
446 | QUIT; | |
447 | ||
448 | /* If we don't know how to compute FRAME's base address, don't give up: | |
449 | maybe the frame we are looking for is upper in the stace frame. */ | |
450 | if (framefunc != NULL | |
2091da29 | 451 | && SYMBOL_BLOCK_OPS (framefunc) != NULL |
63e43d3a PMR |
452 | && SYMBOL_BLOCK_OPS (framefunc)->get_frame_base != NULL |
453 | && (SYMBOL_BLOCK_OPS (framefunc)->get_frame_base (framefunc, frame) | |
454 | == upper_frame_base)) | |
455 | break; | |
456 | } | |
457 | ||
458 | return frame; | |
459 | } | |
460 | ||
461 | /* Assuming VAR is a symbol that can be reached from FRAME thanks to lexical | |
462 | rules, look for the frame that is actually hosting VAR and return it. If, | |
463 | for some reason, we found no such frame, return NULL. | |
464 | ||
465 | This kind of computation is necessary to correctly handle lexically nested | |
466 | functions. | |
467 | ||
468 | Note that in some cases, we know what scope VAR comes from but we cannot | |
469 | reach the specific frame that hosts the instance of VAR we are looking for. | |
470 | For backward compatibility purposes (with old compilers), we then look for | |
471 | the first frame that can host it. */ | |
472 | ||
473 | static struct frame_info * | |
474 | get_hosting_frame (struct symbol *var, const struct block *var_block, | |
475 | struct frame_info *frame) | |
476 | { | |
477 | const struct block *frame_block = NULL; | |
478 | ||
479 | if (!symbol_read_needs_frame (var)) | |
480 | return NULL; | |
481 | ||
482 | /* Some symbols for local variables have no block: this happens when they are | |
483 | not produced by a debug information reader, for instance when GDB creates | |
484 | synthetic symbols. Without block information, we must assume they are | |
485 | local to FRAME. In this case, there is nothing to do. */ | |
486 | else if (var_block == NULL) | |
487 | return frame; | |
488 | ||
489 | /* We currently assume that all symbols with a location list need a frame. | |
490 | This is true in practice because selecting the location description | |
491 | requires to compute the CFA, hence requires a frame. However we have | |
492 | tests that embed global/static symbols with null location lists. | |
493 | We want to get <optimized out> instead of <frame required> when evaluating | |
494 | them so return a frame instead of raising an error. */ | |
495 | else if (var_block == block_global_block (var_block) | |
496 | || var_block == block_static_block (var_block)) | |
497 | return frame; | |
498 | ||
499 | /* We have to handle the "my_func::my_local_var" notation. This requires us | |
500 | to look for upper frames when we find no block for the current frame: here | |
501 | and below, handle when frame_block == NULL. */ | |
502 | if (frame != NULL) | |
503 | frame_block = get_frame_block (frame, NULL); | |
504 | ||
505 | /* Climb up the call stack until reaching the frame we are looking for. */ | |
506 | while (frame != NULL && frame_block != var_block) | |
507 | { | |
508 | /* Stacks can be quite deep: give the user a chance to stop this. */ | |
509 | QUIT; | |
510 | ||
511 | if (frame_block == NULL) | |
512 | { | |
513 | frame = get_prev_frame (frame); | |
514 | if (frame == NULL) | |
515 | break; | |
516 | frame_block = get_frame_block (frame, NULL); | |
517 | } | |
518 | ||
519 | /* If we failed to find the proper frame, fallback to the heuristic | |
520 | method below. */ | |
521 | else if (frame_block == block_global_block (frame_block)) | |
522 | { | |
523 | frame = NULL; | |
524 | break; | |
525 | } | |
526 | ||
527 | /* Assuming we have a block for this frame: if we are at the function | |
528 | level, the immediate upper lexical block is in an outer function: | |
529 | follow the static link. */ | |
530 | else if (BLOCK_FUNCTION (frame_block)) | |
531 | { | |
532 | const struct dynamic_prop *static_link | |
533 | = block_static_link (frame_block); | |
534 | int could_climb_up = 0; | |
535 | ||
536 | if (static_link != NULL) | |
537 | { | |
538 | frame = follow_static_link (frame, static_link); | |
539 | if (frame != NULL) | |
540 | { | |
541 | frame_block = get_frame_block (frame, NULL); | |
542 | could_climb_up = frame_block != NULL; | |
543 | } | |
544 | } | |
545 | if (!could_climb_up) | |
546 | { | |
547 | frame = NULL; | |
548 | break; | |
549 | } | |
550 | } | |
551 | ||
552 | else | |
553 | /* We must be in some function nested lexical block. Just get the | |
554 | outer block: both must share the same frame. */ | |
555 | frame_block = BLOCK_SUPERBLOCK (frame_block); | |
556 | } | |
557 | ||
558 | /* Old compilers may not provide a static link, or they may provide an | |
559 | invalid one. For such cases, fallback on the old way to evaluate | |
560 | non-local references: just climb up the call stack and pick the first | |
561 | frame that contains the variable we are looking for. */ | |
562 | if (frame == NULL) | |
563 | { | |
564 | frame = block_innermost_frame (var_block); | |
565 | if (frame == NULL) | |
566 | { | |
567 | if (BLOCK_FUNCTION (var_block) | |
568 | && !block_inlined_p (var_block) | |
569 | && SYMBOL_PRINT_NAME (BLOCK_FUNCTION (var_block))) | |
570 | error (_("No frame is currently executing in block %s."), | |
571 | SYMBOL_PRINT_NAME (BLOCK_FUNCTION (var_block))); | |
572 | else | |
573 | error (_("No frame is currently executing in specified" | |
574 | " block")); | |
575 | } | |
576 | } | |
577 | ||
578 | return frame; | |
579 | } | |
580 | ||
a5ee536b JB |
581 | /* A default implementation for the "la_read_var_value" hook in |
582 | the language vector which should work in most situations. */ | |
c906108c | 583 | |
3d6d86c6 | 584 | struct value * |
63e43d3a PMR |
585 | default_read_var_value (struct symbol *var, const struct block *var_block, |
586 | struct frame_info *frame) | |
c906108c | 587 | { |
52f0bd74 | 588 | struct value *v; |
c906108c SS |
589 | struct type *type = SYMBOL_TYPE (var); |
590 | CORE_ADDR addr; | |
0b31a4bc | 591 | enum symbol_needs_kind sym_need; |
c906108c | 592 | |
41e8491f JK |
593 | /* Call check_typedef on our type to make sure that, if TYPE is |
594 | a TYPE_CODE_TYPEDEF, its length is set to the length of the target type | |
595 | instead of zero. However, we do not replace the typedef type by the | |
596 | target type, because we want to keep the typedef in order to be able to | |
597 | set the returned value type description correctly. */ | |
598 | check_typedef (type); | |
c906108c | 599 | |
0b31a4bc TT |
600 | sym_need = symbol_read_needs (var); |
601 | if (sym_need == SYMBOL_NEEDS_FRAME) | |
63e43d3a | 602 | gdb_assert (frame != NULL); |
0b31a4bc TT |
603 | else if (sym_need == SYMBOL_NEEDS_REGISTERS && !target_has_registers) |
604 | error (_("Cannot read `%s' without registers"), SYMBOL_PRINT_NAME (var)); | |
63e43d3a PMR |
605 | |
606 | if (frame != NULL) | |
607 | frame = get_hosting_frame (var, var_block, frame); | |
c906108c | 608 | |
24d6c2a0 TT |
609 | if (SYMBOL_COMPUTED_OPS (var) != NULL) |
610 | return SYMBOL_COMPUTED_OPS (var)->read_variable (var, frame); | |
611 | ||
c906108c SS |
612 | switch (SYMBOL_CLASS (var)) |
613 | { | |
614 | case LOC_CONST: | |
1612e0c0 SA |
615 | if (is_dynamic_type (type)) |
616 | { | |
617 | /* Value is a constant byte-sequence and needs no memory access. */ | |
c3345124 | 618 | type = resolve_dynamic_type (type, NULL, /* Unused address. */ 0); |
1612e0c0 SA |
619 | } |
620 | /* Put the constant back in target format. */ | |
41e8491f | 621 | v = allocate_value (type); |
744a8059 | 622 | store_signed_integer (value_contents_raw (v), TYPE_LENGTH (type), |
e17a4113 | 623 | gdbarch_byte_order (get_type_arch (type)), |
c906108c SS |
624 | (LONGEST) SYMBOL_VALUE (var)); |
625 | VALUE_LVAL (v) = not_lval; | |
626 | return v; | |
627 | ||
628 | case LOC_LABEL: | |
629 | /* Put the constant back in target format. */ | |
41e8491f | 630 | v = allocate_value (type); |
c906108c | 631 | if (overlay_debugging) |
4478b372 JB |
632 | { |
633 | CORE_ADDR addr | |
634 | = symbol_overlayed_address (SYMBOL_VALUE_ADDRESS (var), | |
08be3fe3 | 635 | SYMBOL_OBJ_SECTION (symbol_objfile (var), |
e27d198c | 636 | var)); |
bb9bcb69 | 637 | |
990a07ab | 638 | store_typed_address (value_contents_raw (v), type, addr); |
4478b372 | 639 | } |
c906108c | 640 | else |
990a07ab | 641 | store_typed_address (value_contents_raw (v), type, |
4478b372 | 642 | SYMBOL_VALUE_ADDRESS (var)); |
c906108c SS |
643 | VALUE_LVAL (v) = not_lval; |
644 | return v; | |
645 | ||
646 | case LOC_CONST_BYTES: | |
1612e0c0 SA |
647 | if (is_dynamic_type (type)) |
648 | { | |
649 | /* Value is a constant byte-sequence and needs no memory access. */ | |
c3345124 | 650 | type = resolve_dynamic_type (type, NULL, /* Unused address. */ 0); |
1612e0c0 | 651 | } |
41e8491f | 652 | v = allocate_value (type); |
744a8059 SP |
653 | memcpy (value_contents_raw (v), SYMBOL_VALUE_BYTES (var), |
654 | TYPE_LENGTH (type)); | |
bb9bcb69 MS |
655 | VALUE_LVAL (v) = not_lval; |
656 | return v; | |
c906108c SS |
657 | |
658 | case LOC_STATIC: | |
659 | if (overlay_debugging) | |
660 | addr = symbol_overlayed_address (SYMBOL_VALUE_ADDRESS (var), | |
08be3fe3 | 661 | SYMBOL_OBJ_SECTION (symbol_objfile (var), |
e27d198c | 662 | var)); |
c906108c SS |
663 | else |
664 | addr = SYMBOL_VALUE_ADDRESS (var); | |
665 | break; | |
666 | ||
c906108c | 667 | case LOC_ARG: |
da62e633 | 668 | addr = get_frame_args_address (frame); |
c906108c | 669 | if (!addr) |
8afd712c JK |
670 | error (_("Unknown argument list address for `%s'."), |
671 | SYMBOL_PRINT_NAME (var)); | |
c906108c SS |
672 | addr += SYMBOL_VALUE (var); |
673 | break; | |
674 | ||
675 | case LOC_REF_ARG: | |
f76febae AC |
676 | { |
677 | struct value *ref; | |
678 | CORE_ADDR argref; | |
bb9bcb69 | 679 | |
da62e633 | 680 | argref = get_frame_args_address (frame); |
f76febae | 681 | if (!argref) |
8afd712c JK |
682 | error (_("Unknown argument list address for `%s'."), |
683 | SYMBOL_PRINT_NAME (var)); | |
f76febae | 684 | argref += SYMBOL_VALUE (var); |
00a4c844 | 685 | ref = value_at (lookup_pointer_type (type), argref); |
1aa20aa8 | 686 | addr = value_as_address (ref); |
f76febae AC |
687 | break; |
688 | } | |
c906108c SS |
689 | |
690 | case LOC_LOCAL: | |
da62e633 | 691 | addr = get_frame_locals_address (frame); |
c906108c SS |
692 | addr += SYMBOL_VALUE (var); |
693 | break; | |
694 | ||
c906108c | 695 | case LOC_TYPEDEF: |
8afd712c JK |
696 | error (_("Cannot look up value of a typedef `%s'."), |
697 | SYMBOL_PRINT_NAME (var)); | |
c906108c SS |
698 | break; |
699 | ||
700 | case LOC_BLOCK: | |
701 | if (overlay_debugging) | |
41e8491f | 702 | addr = symbol_overlayed_address |
08be3fe3 DE |
703 | (BLOCK_START (SYMBOL_BLOCK_VALUE (var)), |
704 | SYMBOL_OBJ_SECTION (symbol_objfile (var), var)); | |
c906108c | 705 | else |
41e8491f JK |
706 | addr = BLOCK_START (SYMBOL_BLOCK_VALUE (var)); |
707 | break; | |
c906108c SS |
708 | |
709 | case LOC_REGISTER: | |
c906108c SS |
710 | case LOC_REGPARM_ADDR: |
711 | { | |
768a979c UW |
712 | int regno = SYMBOL_REGISTER_OPS (var) |
713 | ->register_number (var, get_frame_arch (frame)); | |
3d6d86c6 | 714 | struct value *regval; |
c906108c | 715 | |
c906108c SS |
716 | if (SYMBOL_CLASS (var) == LOC_REGPARM_ADDR) |
717 | { | |
718 | regval = value_from_register (lookup_pointer_type (type), | |
c5aa993b | 719 | regno, |
c906108c SS |
720 | frame); |
721 | ||
722 | if (regval == NULL) | |
8afd712c JK |
723 | error (_("Value of register variable not available for `%s'."), |
724 | SYMBOL_PRINT_NAME (var)); | |
c906108c | 725 | |
1aa20aa8 | 726 | addr = value_as_address (regval); |
c906108c SS |
727 | } |
728 | else | |
729 | { | |
730 | regval = value_from_register (type, regno, frame); | |
731 | ||
732 | if (regval == NULL) | |
8afd712c JK |
733 | error (_("Value of register variable not available for `%s'."), |
734 | SYMBOL_PRINT_NAME (var)); | |
c906108c SS |
735 | return regval; |
736 | } | |
737 | } | |
738 | break; | |
739 | ||
4c2df51b | 740 | case LOC_COMPUTED: |
24d6c2a0 | 741 | gdb_assert_not_reached (_("LOC_COMPUTED variable missing a method")); |
4c2df51b | 742 | |
c906108c SS |
743 | case LOC_UNRESOLVED: |
744 | { | |
19630284 | 745 | struct minsym_lookup_data lookup_data; |
c906108c | 746 | struct minimal_symbol *msym; |
e0740f77 | 747 | struct obj_section *obj_section; |
c906108c | 748 | |
19630284 JB |
749 | memset (&lookup_data, 0, sizeof (lookup_data)); |
750 | lookup_data.name = SYMBOL_LINKAGE_NAME (var); | |
751 | ||
752 | gdbarch_iterate_over_objfiles_in_search_order | |
08be3fe3 | 753 | (symbol_arch (var), |
19630284 | 754 | minsym_lookup_iterator_cb, &lookup_data, |
08be3fe3 | 755 | symbol_objfile (var)); |
3b7344d5 | 756 | msym = lookup_data.result.minsym; |
19630284 | 757 | |
015d2e7e DE |
758 | /* If we can't find the minsym there's a problem in the symbol info. |
759 | The symbol exists in the debug info, but it's missing in the minsym | |
760 | table. */ | |
c906108c | 761 | if (msym == NULL) |
015d2e7e DE |
762 | { |
763 | const char *flavour_name | |
764 | = objfile_flavour_name (symbol_objfile (var)); | |
765 | ||
766 | /* We can't get here unless we've opened the file, so flavour_name | |
767 | can't be NULL. */ | |
768 | gdb_assert (flavour_name != NULL); | |
769 | error (_("Missing %s symbol \"%s\"."), | |
770 | flavour_name, SYMBOL_LINKAGE_NAME (var)); | |
771 | } | |
3b7344d5 | 772 | obj_section = MSYMBOL_OBJ_SECTION (lookup_data.result.objfile, msym); |
5382cfab PW |
773 | /* Relocate address, unless there is no section or the variable is |
774 | a TLS variable. */ | |
775 | if (obj_section == NULL | |
776 | || (obj_section->the_bfd_section->flags & SEC_THREAD_LOCAL) != 0) | |
777 | addr = MSYMBOL_VALUE_RAW_ADDRESS (msym); | |
778 | else | |
779 | addr = BMSYMBOL_VALUE_ADDRESS (lookup_data.result); | |
780 | if (overlay_debugging) | |
781 | addr = symbol_overlayed_address (addr, obj_section); | |
782 | /* Determine address of TLS variable. */ | |
e0740f77 JK |
783 | if (obj_section |
784 | && (obj_section->the_bfd_section->flags & SEC_THREAD_LOCAL) != 0) | |
785 | addr = target_translate_tls_address (obj_section->objfile, addr); | |
c906108c SS |
786 | } |
787 | break; | |
788 | ||
789 | case LOC_OPTIMIZED_OUT: | |
a7035dbb | 790 | return allocate_optimized_out_value (type); |
c906108c SS |
791 | |
792 | default: | |
8afd712c JK |
793 | error (_("Cannot look up value of a botched symbol `%s'."), |
794 | SYMBOL_PRINT_NAME (var)); | |
c906108c SS |
795 | break; |
796 | } | |
797 | ||
08039c9e | 798 | v = value_at_lazy (type, addr); |
c906108c SS |
799 | return v; |
800 | } | |
801 | ||
a5ee536b JB |
802 | /* Calls VAR's language la_read_var_value hook with the given arguments. */ |
803 | ||
804 | struct value * | |
63e43d3a PMR |
805 | read_var_value (struct symbol *var, const struct block *var_block, |
806 | struct frame_info *frame) | |
a5ee536b JB |
807 | { |
808 | const struct language_defn *lang = language_def (SYMBOL_LANGUAGE (var)); | |
809 | ||
810 | gdb_assert (lang != NULL); | |
811 | gdb_assert (lang->la_read_var_value != NULL); | |
812 | ||
63e43d3a | 813 | return lang->la_read_var_value (var, var_block, frame); |
a5ee536b JB |
814 | } |
815 | ||
9acbedc0 UW |
816 | /* Install default attributes for register values. */ |
817 | ||
818 | struct value * | |
2ed3c037 UW |
819 | default_value_from_register (struct gdbarch *gdbarch, struct type *type, |
820 | int regnum, struct frame_id frame_id) | |
9acbedc0 | 821 | { |
9acbedc0 UW |
822 | int len = TYPE_LENGTH (type); |
823 | struct value *value = allocate_value (type); | |
41b56feb | 824 | struct frame_info *frame; |
9acbedc0 UW |
825 | |
826 | VALUE_LVAL (value) = lval_register; | |
41b56feb KB |
827 | frame = frame_find_by_id (frame_id); |
828 | ||
829 | if (frame == NULL) | |
830 | frame_id = null_frame_id; | |
831 | else | |
832 | frame_id = get_frame_id (get_next_frame_sentinel_okay (frame)); | |
833 | ||
834 | VALUE_NEXT_FRAME_ID (value) = frame_id; | |
9acbedc0 UW |
835 | VALUE_REGNUM (value) = regnum; |
836 | ||
837 | /* Any structure stored in more than one register will always be | |
838 | an integral number of registers. Otherwise, you need to do | |
839 | some fiddling with the last register copied here for little | |
840 | endian machines. */ | |
e9e45075 | 841 | if (gdbarch_byte_order (gdbarch) == BFD_ENDIAN_BIG |
9acbedc0 UW |
842 | && len < register_size (gdbarch, regnum)) |
843 | /* Big-endian, and we want less than full size. */ | |
844 | set_value_offset (value, register_size (gdbarch, regnum) - len); | |
845 | else | |
846 | set_value_offset (value, 0); | |
847 | ||
848 | return value; | |
849 | } | |
850 | ||
b56d6f31 JB |
851 | /* VALUE must be an lval_register value. If regnum is the value's |
852 | associated register number, and len the length of the values type, | |
853 | read one or more registers in FRAME, starting with register REGNUM, | |
2603f7ee AB |
854 | until we've read LEN bytes. |
855 | ||
856 | If any of the registers we try to read are optimized out, then mark the | |
857 | complete resulting value as optimized out. */ | |
b56d6f31 JB |
858 | |
859 | void | |
860 | read_frame_register_value (struct value *value, struct frame_info *frame) | |
861 | { | |
01efb936 | 862 | struct gdbarch *gdbarch = get_frame_arch (frame); |
6b850546 DT |
863 | LONGEST offset = 0; |
864 | LONGEST reg_offset = value_offset (value); | |
b56d6f31 | 865 | int regnum = VALUE_REGNUM (value); |
3ae385af | 866 | int len = type_length_units (check_typedef (value_type (value))); |
b56d6f31 JB |
867 | |
868 | gdb_assert (VALUE_LVAL (value) == lval_register); | |
869 | ||
01efb936 UW |
870 | /* Skip registers wholly inside of REG_OFFSET. */ |
871 | while (reg_offset >= register_size (gdbarch, regnum)) | |
872 | { | |
873 | reg_offset -= register_size (gdbarch, regnum); | |
874 | regnum++; | |
875 | } | |
876 | ||
877 | /* Copy the data. */ | |
878 | while (len > 0) | |
b56d6f31 JB |
879 | { |
880 | struct value *regval = get_frame_register_value (frame, regnum); | |
3ae385af | 881 | int reg_len = type_length_units (value_type (regval)) - reg_offset; |
b56d6f31 | 882 | |
22355c90 JB |
883 | /* If the register length is larger than the number of bytes |
884 | remaining to copy, then only copy the appropriate bytes. */ | |
01efb936 UW |
885 | if (reg_len > len) |
886 | reg_len = len; | |
22355c90 | 887 | |
01efb936 | 888 | value_contents_copy (value, offset, regval, reg_offset, reg_len); |
b56d6f31 JB |
889 | |
890 | offset += reg_len; | |
01efb936 UW |
891 | len -= reg_len; |
892 | reg_offset = 0; | |
b56d6f31 JB |
893 | regnum++; |
894 | } | |
895 | } | |
896 | ||
00fa51f6 | 897 | /* Return a value of type TYPE, stored in register REGNUM, in frame FRAME. */ |
c906108c | 898 | |
3d6d86c6 | 899 | struct value * |
fba45db2 | 900 | value_from_register (struct type *type, int regnum, struct frame_info *frame) |
c906108c | 901 | { |
ff2e87ac | 902 | struct gdbarch *gdbarch = get_frame_arch (frame); |
9acbedc0 UW |
903 | struct type *type1 = check_typedef (type); |
904 | struct value *v; | |
905 | ||
e9e45075 | 906 | if (gdbarch_convert_register_p (gdbarch, regnum, type1)) |
ff2e87ac | 907 | { |
3543a589 TT |
908 | int optim, unavail, ok; |
909 | ||
ff2e87ac AC |
910 | /* The ISA/ABI need to something weird when obtaining the |
911 | specified value from this register. It might need to | |
912 | re-order non-adjacent, starting with REGNUM (see MIPS and | |
913 | i386). It might need to convert the [float] register into | |
914 | the corresponding [integer] type (see Alpha). The assumption | |
c1afe53d | 915 | is that gdbarch_register_to_value populates the entire value |
ff2e87ac | 916 | including the location. */ |
9acbedc0 UW |
917 | v = allocate_value (type); |
918 | VALUE_LVAL (v) = lval_register; | |
41b56feb | 919 | VALUE_NEXT_FRAME_ID (v) = get_frame_id (get_next_frame_sentinel_okay (frame)); |
9acbedc0 | 920 | VALUE_REGNUM (v) = regnum; |
8dccd430 PA |
921 | ok = gdbarch_register_to_value (gdbarch, frame, regnum, type1, |
922 | value_contents_raw (v), &optim, | |
923 | &unavail); | |
3543a589 TT |
924 | |
925 | if (!ok) | |
926 | { | |
927 | if (optim) | |
9a0dc9e3 | 928 | mark_value_bytes_optimized_out (v, 0, TYPE_LENGTH (type)); |
3543a589 TT |
929 | if (unavail) |
930 | mark_value_bytes_unavailable (v, 0, TYPE_LENGTH (type)); | |
931 | } | |
ff2e87ac AC |
932 | } |
933 | else | |
c906108c | 934 | { |
9acbedc0 | 935 | /* Construct the value. */ |
2ed3c037 UW |
936 | v = gdbarch_value_from_register (gdbarch, type, |
937 | regnum, get_frame_id (frame)); | |
00fa51f6 UW |
938 | |
939 | /* Get the data. */ | |
b56d6f31 | 940 | read_frame_register_value (v, frame); |
c906108c | 941 | } |
8dccd430 | 942 | |
c906108c SS |
943 | return v; |
944 | } | |
ff2e87ac | 945 | |
2ed3c037 UW |
946 | /* Return contents of register REGNUM in frame FRAME as address. |
947 | Will abort if register value is not available. */ | |
0b2b0195 UW |
948 | |
949 | CORE_ADDR | |
2ed3c037 | 950 | address_from_register (int regnum, struct frame_info *frame) |
0b2b0195 | 951 | { |
2ed3c037 UW |
952 | struct gdbarch *gdbarch = get_frame_arch (frame); |
953 | struct type *type = builtin_type (gdbarch)->builtin_data_ptr; | |
0b2b0195 UW |
954 | struct value *value; |
955 | CORE_ADDR result; | |
5f3ff4f8 JK |
956 | int regnum_max_excl = (gdbarch_num_regs (gdbarch) |
957 | + gdbarch_num_pseudo_regs (gdbarch)); | |
958 | ||
959 | if (regnum < 0 || regnum >= regnum_max_excl) | |
960 | error (_("Invalid register #%d, expecting 0 <= # < %d"), regnum, | |
961 | regnum_max_excl); | |
0b2b0195 | 962 | |
2ed3c037 UW |
963 | /* This routine may be called during early unwinding, at a time |
964 | where the ID of FRAME is not yet known. Calling value_from_register | |
965 | would therefore abort in get_frame_id. However, since we only need | |
966 | a temporary value that is never used as lvalue, we actually do not | |
41b56feb | 967 | really need to set its VALUE_NEXT_FRAME_ID. Therefore, we re-implement |
eeef931a | 968 | the core of value_from_register, but use the null_frame_id. */ |
2ed3c037 | 969 | |
eeef931a UW |
970 | /* Some targets require a special conversion routine even for plain |
971 | pointer types. Avoid constructing a value object in those cases. */ | |
972 | if (gdbarch_convert_register_p (gdbarch, regnum, type)) | |
973 | { | |
224c3ddb | 974 | gdb_byte *buf = (gdb_byte *) alloca (TYPE_LENGTH (type)); |
eeef931a UW |
975 | int optim, unavail, ok; |
976 | ||
977 | ok = gdbarch_register_to_value (gdbarch, frame, regnum, type, | |
978 | buf, &optim, &unavail); | |
979 | if (!ok) | |
980 | { | |
981 | /* This function is used while computing a location expression. | |
982 | Complain about the value being optimized out, rather than | |
983 | letting value_as_address complain about some random register | |
984 | the expression depends on not being saved. */ | |
985 | error_value_optimized_out (); | |
986 | } | |
987 | ||
988 | return unpack_long (type, buf); | |
989 | } | |
2ed3c037 UW |
990 | |
991 | value = gdbarch_value_from_register (gdbarch, type, regnum, null_frame_id); | |
992 | read_frame_register_value (value, frame); | |
0b2b0195 | 993 | |
901461f8 PA |
994 | if (value_optimized_out (value)) |
995 | { | |
996 | /* This function is used while computing a location expression. | |
997 | Complain about the value being optimized out, rather than | |
998 | letting value_as_address complain about some random register | |
999 | the expression depends on not being saved. */ | |
1000 | error_value_optimized_out (); | |
1001 | } | |
1002 | ||
0b2b0195 UW |
1003 | result = value_as_address (value); |
1004 | release_value (value); | |
1005 | value_free (value); | |
1006 | ||
1007 | return result; | |
1008 | } | |
b56d6f31 | 1009 |