Commit | Line | Data |
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4c2df51b | 1 | /* DWARF 2 location expression support for GDB. |
feb13ab0 | 2 | |
4c38e0a4 JB |
3 | Copyright (C) 2003, 2005, 2007, 2008, 2009, 2010 |
4 | Free Software Foundation, Inc. | |
feb13ab0 | 5 | |
4c2df51b DJ |
6 | Contributed by Daniel Jacobowitz, MontaVista Software, Inc. |
7 | ||
8 | This file is part of GDB. | |
9 | ||
10 | This program is free software; you can redistribute it and/or modify | |
11 | it under the terms of the GNU General Public License as published by | |
a9762ec7 JB |
12 | the Free Software Foundation; either version 3 of the License, or |
13 | (at your option) any later version. | |
4c2df51b | 14 | |
a9762ec7 JB |
15 | This program is distributed in the hope that it will be useful, |
16 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
17 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
18 | GNU General Public License for more details. | |
4c2df51b DJ |
19 | |
20 | You should have received a copy of the GNU General Public License | |
a9762ec7 | 21 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ |
4c2df51b DJ |
22 | |
23 | #include "defs.h" | |
24 | #include "ui-out.h" | |
25 | #include "value.h" | |
26 | #include "frame.h" | |
27 | #include "gdbcore.h" | |
28 | #include "target.h" | |
29 | #include "inferior.h" | |
a55cc764 DJ |
30 | #include "ax.h" |
31 | #include "ax-gdb.h" | |
e4adbba9 | 32 | #include "regcache.h" |
c3228f12 | 33 | #include "objfiles.h" |
93ad78a7 | 34 | #include "exceptions.h" |
edb3359d | 35 | #include "block.h" |
4c2df51b | 36 | |
fa8f86ff | 37 | #include "dwarf2.h" |
4c2df51b DJ |
38 | #include "dwarf2expr.h" |
39 | #include "dwarf2loc.h" | |
e7802207 | 40 | #include "dwarf2-frame.h" |
4c2df51b DJ |
41 | |
42 | #include "gdb_string.h" | |
eff4f95e | 43 | #include "gdb_assert.h" |
4c2df51b | 44 | |
0936ad1d SS |
45 | static void |
46 | dwarf_expr_frame_base_1 (struct symbol *framefunc, CORE_ADDR pc, | |
47 | gdb_byte **start, size_t *length); | |
48 | ||
0d53c4c4 DJ |
49 | /* A helper function for dealing with location lists. Given a |
50 | symbol baton (BATON) and a pc value (PC), find the appropriate | |
51 | location expression, set *LOCEXPR_LENGTH, and return a pointer | |
52 | to the beginning of the expression. Returns NULL on failure. | |
53 | ||
54 | For now, only return the first matching location expression; there | |
55 | can be more than one in the list. */ | |
56 | ||
852483bc | 57 | static gdb_byte * |
0d53c4c4 | 58 | find_location_expression (struct dwarf2_loclist_baton *baton, |
b6b08ebf | 59 | size_t *locexpr_length, CORE_ADDR pc) |
0d53c4c4 | 60 | { |
0d53c4c4 | 61 | CORE_ADDR low, high; |
852483bc MK |
62 | gdb_byte *loc_ptr, *buf_end; |
63 | int length; | |
ae0d2f24 | 64 | struct objfile *objfile = dwarf2_per_cu_objfile (baton->per_cu); |
f7fd4728 | 65 | struct gdbarch *gdbarch = get_objfile_arch (objfile); |
e17a4113 | 66 | enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); |
ae0d2f24 | 67 | unsigned int addr_size = dwarf2_per_cu_addr_size (baton->per_cu); |
0d53c4c4 | 68 | CORE_ADDR base_mask = ~(~(CORE_ADDR)1 << (addr_size * 8 - 1)); |
8edfa926 | 69 | /* Adjust base_address for relocatable objects. */ |
ae0d2f24 UW |
70 | CORE_ADDR base_offset = ANOFFSET (objfile->section_offsets, |
71 | SECT_OFF_TEXT (objfile)); | |
8edfa926 | 72 | CORE_ADDR base_address = baton->base_address + base_offset; |
0d53c4c4 DJ |
73 | |
74 | loc_ptr = baton->data; | |
75 | buf_end = baton->data + baton->size; | |
76 | ||
77 | while (1) | |
78 | { | |
b5758fe4 UW |
79 | if (buf_end - loc_ptr < 2 * addr_size) |
80 | error (_("find_location_expression: Corrupted DWARF expression.")); | |
0d53c4c4 | 81 | |
b5758fe4 UW |
82 | low = extract_unsigned_integer (loc_ptr, addr_size, byte_order); |
83 | loc_ptr += addr_size; | |
0d53c4c4 DJ |
84 | |
85 | /* A base-address-selection entry. */ | |
b5758fe4 | 86 | if (low == base_mask) |
0d53c4c4 | 87 | { |
b5758fe4 UW |
88 | base_address = dwarf2_read_address (gdbarch, |
89 | loc_ptr, buf_end, addr_size); | |
90 | loc_ptr += addr_size; | |
0d53c4c4 DJ |
91 | continue; |
92 | } | |
93 | ||
b5758fe4 UW |
94 | high = extract_unsigned_integer (loc_ptr, addr_size, byte_order); |
95 | loc_ptr += addr_size; | |
96 | ||
97 | /* An end-of-list entry. */ | |
98 | if (low == 0 && high == 0) | |
99 | return NULL; | |
100 | ||
0d53c4c4 DJ |
101 | /* Otherwise, a location expression entry. */ |
102 | low += base_address; | |
103 | high += base_address; | |
104 | ||
e17a4113 | 105 | length = extract_unsigned_integer (loc_ptr, 2, byte_order); |
0d53c4c4 DJ |
106 | loc_ptr += 2; |
107 | ||
108 | if (pc >= low && pc < high) | |
109 | { | |
110 | *locexpr_length = length; | |
111 | return loc_ptr; | |
112 | } | |
113 | ||
114 | loc_ptr += length; | |
115 | } | |
116 | } | |
117 | ||
4c2df51b DJ |
118 | /* This is the baton used when performing dwarf2 expression |
119 | evaluation. */ | |
120 | struct dwarf_expr_baton | |
121 | { | |
122 | struct frame_info *frame; | |
123 | struct objfile *objfile; | |
124 | }; | |
125 | ||
126 | /* Helper functions for dwarf2_evaluate_loc_desc. */ | |
127 | ||
4bc9efe1 | 128 | /* Using the frame specified in BATON, return the value of register |
0b2b0195 | 129 | REGNUM, treated as a pointer. */ |
4c2df51b | 130 | static CORE_ADDR |
61fbb938 | 131 | dwarf_expr_read_reg (void *baton, int dwarf_regnum) |
4c2df51b | 132 | { |
4c2df51b | 133 | struct dwarf_expr_baton *debaton = (struct dwarf_expr_baton *) baton; |
5e2b427d | 134 | struct gdbarch *gdbarch = get_frame_arch (debaton->frame); |
e5192dd8 | 135 | CORE_ADDR result; |
0b2b0195 | 136 | int regnum; |
e4adbba9 | 137 | |
5e2b427d UW |
138 | regnum = gdbarch_dwarf2_reg_to_regnum (gdbarch, dwarf_regnum); |
139 | result = address_from_register (builtin_type (gdbarch)->builtin_data_ptr, | |
0b2b0195 | 140 | regnum, debaton->frame); |
4c2df51b DJ |
141 | return result; |
142 | } | |
143 | ||
144 | /* Read memory at ADDR (length LEN) into BUF. */ | |
145 | ||
146 | static void | |
852483bc | 147 | dwarf_expr_read_mem (void *baton, gdb_byte *buf, CORE_ADDR addr, size_t len) |
4c2df51b DJ |
148 | { |
149 | read_memory (addr, buf, len); | |
150 | } | |
151 | ||
152 | /* Using the frame specified in BATON, find the location expression | |
153 | describing the frame base. Return a pointer to it in START and | |
154 | its length in LENGTH. */ | |
155 | static void | |
852483bc | 156 | dwarf_expr_frame_base (void *baton, gdb_byte **start, size_t * length) |
4c2df51b | 157 | { |
da62e633 AC |
158 | /* FIXME: cagney/2003-03-26: This code should be using |
159 | get_frame_base_address(), and then implement a dwarf2 specific | |
160 | this_base method. */ | |
4c2df51b | 161 | struct symbol *framefunc; |
4c2df51b | 162 | struct dwarf_expr_baton *debaton = (struct dwarf_expr_baton *) baton; |
0d53c4c4 | 163 | |
edb3359d DJ |
164 | /* Use block_linkage_function, which returns a real (not inlined) |
165 | function, instead of get_frame_function, which may return an | |
166 | inlined function. */ | |
167 | framefunc = block_linkage_function (get_frame_block (debaton->frame, NULL)); | |
0d53c4c4 | 168 | |
eff4f95e JG |
169 | /* If we found a frame-relative symbol then it was certainly within |
170 | some function associated with a frame. If we can't find the frame, | |
171 | something has gone wrong. */ | |
172 | gdb_assert (framefunc != NULL); | |
173 | ||
0936ad1d SS |
174 | dwarf_expr_frame_base_1 (framefunc, |
175 | get_frame_address_in_block (debaton->frame), | |
176 | start, length); | |
177 | } | |
178 | ||
179 | static void | |
180 | dwarf_expr_frame_base_1 (struct symbol *framefunc, CORE_ADDR pc, | |
181 | gdb_byte **start, size_t *length) | |
182 | { | |
edb3359d DJ |
183 | if (SYMBOL_LOCATION_BATON (framefunc) == NULL) |
184 | *start = NULL; | |
185 | else if (SYMBOL_COMPUTED_OPS (framefunc) == &dwarf2_loclist_funcs) | |
0d53c4c4 DJ |
186 | { |
187 | struct dwarf2_loclist_baton *symbaton; | |
22c6caba | 188 | |
0d53c4c4 | 189 | symbaton = SYMBOL_LOCATION_BATON (framefunc); |
0936ad1d | 190 | *start = find_location_expression (symbaton, length, pc); |
0d53c4c4 DJ |
191 | } |
192 | else | |
193 | { | |
194 | struct dwarf2_locexpr_baton *symbaton; | |
9a619af0 | 195 | |
0d53c4c4 | 196 | symbaton = SYMBOL_LOCATION_BATON (framefunc); |
ebd3bcc1 JK |
197 | if (symbaton != NULL) |
198 | { | |
199 | *length = symbaton->size; | |
200 | *start = symbaton->data; | |
201 | } | |
202 | else | |
203 | *start = NULL; | |
0d53c4c4 DJ |
204 | } |
205 | ||
206 | if (*start == NULL) | |
8a3fe4f8 | 207 | error (_("Could not find the frame base for \"%s\"."), |
0d53c4c4 | 208 | SYMBOL_NATURAL_NAME (framefunc)); |
4c2df51b DJ |
209 | } |
210 | ||
e7802207 TT |
211 | /* Helper function for dwarf2_evaluate_loc_desc. Computes the CFA for |
212 | the frame in BATON. */ | |
213 | ||
214 | static CORE_ADDR | |
215 | dwarf_expr_frame_cfa (void *baton) | |
216 | { | |
217 | struct dwarf_expr_baton *debaton = (struct dwarf_expr_baton *) baton; | |
9a619af0 | 218 | |
e7802207 TT |
219 | return dwarf2_frame_cfa (debaton->frame); |
220 | } | |
221 | ||
4c2df51b DJ |
222 | /* Using the objfile specified in BATON, find the address for the |
223 | current thread's thread-local storage with offset OFFSET. */ | |
224 | static CORE_ADDR | |
225 | dwarf_expr_tls_address (void *baton, CORE_ADDR offset) | |
226 | { | |
227 | struct dwarf_expr_baton *debaton = (struct dwarf_expr_baton *) baton; | |
4c2df51b | 228 | |
9e35dae4 | 229 | return target_translate_tls_address (debaton->objfile, offset); |
4c2df51b DJ |
230 | } |
231 | ||
052b9502 NF |
232 | struct piece_closure |
233 | { | |
234 | /* The number of pieces used to describe this variable. */ | |
235 | int n_pieces; | |
236 | ||
6063c216 UW |
237 | /* The target address size, used only for DWARF_VALUE_STACK. */ |
238 | int addr_size; | |
cec03d70 | 239 | |
052b9502 NF |
240 | /* The pieces themselves. */ |
241 | struct dwarf_expr_piece *pieces; | |
242 | }; | |
243 | ||
244 | /* Allocate a closure for a value formed from separately-described | |
245 | PIECES. */ | |
246 | ||
247 | static struct piece_closure * | |
cec03d70 | 248 | allocate_piece_closure (int n_pieces, struct dwarf_expr_piece *pieces, |
6063c216 | 249 | int addr_size) |
052b9502 NF |
250 | { |
251 | struct piece_closure *c = XZALLOC (struct piece_closure); | |
252 | ||
253 | c->n_pieces = n_pieces; | |
6063c216 | 254 | c->addr_size = addr_size; |
052b9502 NF |
255 | c->pieces = XCALLOC (n_pieces, struct dwarf_expr_piece); |
256 | ||
257 | memcpy (c->pieces, pieces, n_pieces * sizeof (struct dwarf_expr_piece)); | |
258 | ||
259 | return c; | |
260 | } | |
261 | ||
262 | static void | |
263 | read_pieced_value (struct value *v) | |
264 | { | |
265 | int i; | |
266 | long offset = 0; | |
afd74c5f | 267 | ULONGEST bytes_to_skip; |
052b9502 NF |
268 | gdb_byte *contents; |
269 | struct piece_closure *c = (struct piece_closure *) value_computed_closure (v); | |
270 | struct frame_info *frame = frame_find_by_id (VALUE_FRAME_ID (v)); | |
afd74c5f TT |
271 | size_t type_len; |
272 | ||
273 | if (value_type (v) != value_enclosing_type (v)) | |
274 | internal_error (__FILE__, __LINE__, | |
275 | _("Should not be able to create a lazy value with " | |
276 | "an enclosing type")); | |
052b9502 NF |
277 | |
278 | contents = value_contents_raw (v); | |
afd74c5f TT |
279 | bytes_to_skip = value_offset (v); |
280 | type_len = TYPE_LENGTH (value_type (v)); | |
281 | for (i = 0; i < c->n_pieces && offset < type_len; i++) | |
052b9502 NF |
282 | { |
283 | struct dwarf_expr_piece *p = &c->pieces[i]; | |
afd74c5f TT |
284 | size_t this_size; |
285 | long dest_offset, source_offset; | |
286 | ||
287 | if (bytes_to_skip > 0 && bytes_to_skip >= p->size) | |
288 | { | |
289 | bytes_to_skip -= p->size; | |
290 | continue; | |
291 | } | |
292 | this_size = p->size; | |
293 | if (this_size > type_len - offset) | |
294 | this_size = type_len - offset; | |
295 | if (bytes_to_skip > 0) | |
296 | { | |
297 | dest_offset = 0; | |
298 | source_offset = bytes_to_skip; | |
299 | this_size -= bytes_to_skip; | |
300 | bytes_to_skip = 0; | |
301 | } | |
302 | else | |
303 | { | |
304 | dest_offset = offset; | |
305 | source_offset = 0; | |
306 | } | |
9a619af0 | 307 | |
cec03d70 | 308 | switch (p->location) |
052b9502 | 309 | { |
cec03d70 TT |
310 | case DWARF_VALUE_REGISTER: |
311 | { | |
312 | struct gdbarch *arch = get_frame_arch (frame); | |
cec03d70 | 313 | int gdb_regnum = gdbarch_dwarf2_reg_to_regnum (arch, |
44353522 | 314 | p->v.expr.value); |
afd74c5f | 315 | int reg_offset = source_offset; |
dcbf108f UW |
316 | |
317 | if (gdbarch_byte_order (arch) == BFD_ENDIAN_BIG | |
afd74c5f | 318 | && this_size < register_size (arch, gdb_regnum)) |
dcbf108f | 319 | /* Big-endian, and we want less than full size. */ |
afd74c5f | 320 | reg_offset = register_size (arch, gdb_regnum) - this_size; |
dcbf108f | 321 | |
63b4f126 MGD |
322 | if (gdb_regnum != -1) |
323 | { | |
324 | get_frame_register_bytes (frame, gdb_regnum, reg_offset, | |
afd74c5f | 325 | this_size, contents + dest_offset); |
63b4f126 MGD |
326 | } |
327 | else | |
328 | { | |
329 | error (_("Unable to access DWARF register number %s"), | |
330 | paddress (arch, p->v.expr.value)); | |
331 | } | |
cec03d70 TT |
332 | } |
333 | break; | |
334 | ||
335 | case DWARF_VALUE_MEMORY: | |
44353522 | 336 | if (p->v.expr.in_stack_memory) |
afd74c5f TT |
337 | read_stack (p->v.expr.value + source_offset, |
338 | contents + dest_offset, this_size); | |
44353522 | 339 | else |
afd74c5f TT |
340 | read_memory (p->v.expr.value + source_offset, |
341 | contents + dest_offset, this_size); | |
cec03d70 TT |
342 | break; |
343 | ||
344 | case DWARF_VALUE_STACK: | |
345 | { | |
6063c216 | 346 | struct gdbarch *gdbarch = get_type_arch (value_type (v)); |
afd74c5f | 347 | size_t n = this_size; |
9a619af0 | 348 | |
afd74c5f TT |
349 | if (n > c->addr_size - source_offset) |
350 | n = (c->addr_size >= source_offset | |
351 | ? c->addr_size - source_offset | |
352 | : 0); | |
353 | if (n == 0) | |
354 | { | |
355 | /* Nothing. */ | |
356 | } | |
357 | else if (source_offset == 0) | |
358 | store_unsigned_integer (contents + dest_offset, n, | |
359 | gdbarch_byte_order (gdbarch), | |
360 | p->v.expr.value); | |
361 | else | |
362 | { | |
363 | gdb_byte bytes[sizeof (ULONGEST)]; | |
364 | ||
365 | store_unsigned_integer (bytes, n + source_offset, | |
366 | gdbarch_byte_order (gdbarch), | |
367 | p->v.expr.value); | |
368 | memcpy (contents + dest_offset, bytes + source_offset, n); | |
369 | } | |
cec03d70 TT |
370 | } |
371 | break; | |
372 | ||
373 | case DWARF_VALUE_LITERAL: | |
374 | { | |
afd74c5f TT |
375 | size_t n = this_size; |
376 | ||
377 | if (n > p->v.literal.length - source_offset) | |
378 | n = (p->v.literal.length >= source_offset | |
379 | ? p->v.literal.length - source_offset | |
380 | : 0); | |
381 | if (n != 0) | |
382 | memcpy (contents + dest_offset, | |
383 | p->v.literal.data + source_offset, n); | |
cec03d70 TT |
384 | } |
385 | break; | |
386 | ||
cb826367 TT |
387 | case DWARF_VALUE_OPTIMIZED_OUT: |
388 | /* We just leave the bits empty for now. This is not ideal | |
389 | but gdb currently does not have a nice way to represent | |
390 | optimized-out pieces. */ | |
391 | warning (_("bytes %ld-%ld in computed object were optimized out; " | |
392 | "replacing with zeroes"), | |
393 | offset, | |
394 | offset + (long) this_size); | |
395 | break; | |
396 | ||
cec03d70 TT |
397 | default: |
398 | internal_error (__FILE__, __LINE__, _("invalid location type")); | |
052b9502 | 399 | } |
afd74c5f | 400 | offset += this_size; |
052b9502 NF |
401 | } |
402 | } | |
403 | ||
404 | static void | |
405 | write_pieced_value (struct value *to, struct value *from) | |
406 | { | |
407 | int i; | |
408 | long offset = 0; | |
afd74c5f TT |
409 | ULONGEST bytes_to_skip; |
410 | const gdb_byte *contents; | |
052b9502 NF |
411 | struct piece_closure *c = (struct piece_closure *) value_computed_closure (to); |
412 | struct frame_info *frame = frame_find_by_id (VALUE_FRAME_ID (to)); | |
afd74c5f | 413 | size_t type_len; |
052b9502 NF |
414 | |
415 | if (frame == NULL) | |
416 | { | |
417 | set_value_optimized_out (to, 1); | |
418 | return; | |
419 | } | |
420 | ||
afd74c5f TT |
421 | contents = value_contents (from); |
422 | bytes_to_skip = value_offset (to); | |
423 | type_len = TYPE_LENGTH (value_type (to)); | |
424 | for (i = 0; i < c->n_pieces && offset < type_len; i++) | |
052b9502 NF |
425 | { |
426 | struct dwarf_expr_piece *p = &c->pieces[i]; | |
afd74c5f TT |
427 | size_t this_size; |
428 | long dest_offset, source_offset; | |
429 | ||
430 | if (bytes_to_skip > 0 && bytes_to_skip >= p->size) | |
431 | { | |
432 | bytes_to_skip -= p->size; | |
433 | continue; | |
434 | } | |
435 | this_size = p->size; | |
436 | if (this_size > type_len - offset) | |
437 | this_size = type_len - offset; | |
438 | if (bytes_to_skip > 0) | |
439 | { | |
440 | dest_offset = bytes_to_skip; | |
441 | source_offset = 0; | |
442 | this_size -= bytes_to_skip; | |
443 | bytes_to_skip = 0; | |
444 | } | |
445 | else | |
446 | { | |
447 | dest_offset = 0; | |
448 | source_offset = offset; | |
449 | } | |
9a619af0 | 450 | |
cec03d70 | 451 | switch (p->location) |
052b9502 | 452 | { |
cec03d70 TT |
453 | case DWARF_VALUE_REGISTER: |
454 | { | |
455 | struct gdbarch *arch = get_frame_arch (frame); | |
44353522 | 456 | int gdb_regnum = gdbarch_dwarf2_reg_to_regnum (arch, p->v.expr.value); |
afd74c5f | 457 | int reg_offset = dest_offset; |
dcbf108f UW |
458 | |
459 | if (gdbarch_byte_order (arch) == BFD_ENDIAN_BIG | |
afd74c5f | 460 | && this_size <= register_size (arch, gdb_regnum)) |
dcbf108f | 461 | /* Big-endian, and we want less than full size. */ |
afd74c5f | 462 | reg_offset = register_size (arch, gdb_regnum) - this_size; |
dcbf108f | 463 | |
63b4f126 MGD |
464 | if (gdb_regnum != -1) |
465 | { | |
466 | put_frame_register_bytes (frame, gdb_regnum, reg_offset, | |
afd74c5f | 467 | this_size, contents + source_offset); |
63b4f126 MGD |
468 | } |
469 | else | |
470 | { | |
471 | error (_("Unable to write to DWARF register number %s"), | |
472 | paddress (arch, p->v.expr.value)); | |
473 | } | |
cec03d70 TT |
474 | } |
475 | break; | |
476 | case DWARF_VALUE_MEMORY: | |
afd74c5f TT |
477 | write_memory (p->v.expr.value + dest_offset, |
478 | contents + source_offset, this_size); | |
cec03d70 TT |
479 | break; |
480 | default: | |
481 | set_value_optimized_out (to, 1); | |
482 | return; | |
052b9502 | 483 | } |
afd74c5f | 484 | offset += this_size; |
052b9502 NF |
485 | } |
486 | } | |
487 | ||
488 | static void * | |
489 | copy_pieced_value_closure (struct value *v) | |
490 | { | |
491 | struct piece_closure *c = (struct piece_closure *) value_computed_closure (v); | |
492 | ||
6063c216 | 493 | return allocate_piece_closure (c->n_pieces, c->pieces, c->addr_size); |
052b9502 NF |
494 | } |
495 | ||
496 | static void | |
497 | free_pieced_value_closure (struct value *v) | |
498 | { | |
499 | struct piece_closure *c = (struct piece_closure *) value_computed_closure (v); | |
500 | ||
501 | xfree (c->pieces); | |
502 | xfree (c); | |
503 | } | |
504 | ||
505 | /* Functions for accessing a variable described by DW_OP_piece. */ | |
506 | static struct lval_funcs pieced_value_funcs = { | |
507 | read_pieced_value, | |
508 | write_pieced_value, | |
509 | copy_pieced_value_closure, | |
510 | free_pieced_value_closure | |
511 | }; | |
512 | ||
4c2df51b | 513 | /* Evaluate a location description, starting at DATA and with length |
a2d33775 | 514 | SIZE, to find the current location of variable of TYPE in the context |
4c2df51b | 515 | of FRAME. */ |
a2d33775 | 516 | |
4c2df51b | 517 | static struct value * |
a2d33775 | 518 | dwarf2_evaluate_loc_desc (struct type *type, struct frame_info *frame, |
852483bc | 519 | gdb_byte *data, unsigned short size, |
ae0d2f24 | 520 | struct dwarf2_per_cu_data *per_cu) |
4c2df51b | 521 | { |
4c2df51b DJ |
522 | struct value *retval; |
523 | struct dwarf_expr_baton baton; | |
524 | struct dwarf_expr_context *ctx; | |
4a227398 | 525 | struct cleanup *old_chain; |
4c2df51b | 526 | |
0d53c4c4 DJ |
527 | if (size == 0) |
528 | { | |
a2d33775 | 529 | retval = allocate_value (type); |
0d53c4c4 | 530 | VALUE_LVAL (retval) = not_lval; |
feb13ab0 | 531 | set_value_optimized_out (retval, 1); |
10fb19b6 | 532 | return retval; |
0d53c4c4 DJ |
533 | } |
534 | ||
4c2df51b | 535 | baton.frame = frame; |
ae0d2f24 | 536 | baton.objfile = dwarf2_per_cu_objfile (per_cu); |
4c2df51b DJ |
537 | |
538 | ctx = new_dwarf_expr_context (); | |
4a227398 TT |
539 | old_chain = make_cleanup_free_dwarf_expr_context (ctx); |
540 | ||
f7fd4728 | 541 | ctx->gdbarch = get_objfile_arch (baton.objfile); |
ae0d2f24 | 542 | ctx->addr_size = dwarf2_per_cu_addr_size (per_cu); |
4c2df51b DJ |
543 | ctx->baton = &baton; |
544 | ctx->read_reg = dwarf_expr_read_reg; | |
545 | ctx->read_mem = dwarf_expr_read_mem; | |
546 | ctx->get_frame_base = dwarf_expr_frame_base; | |
e7802207 | 547 | ctx->get_frame_cfa = dwarf_expr_frame_cfa; |
4c2df51b DJ |
548 | ctx->get_tls_address = dwarf_expr_tls_address; |
549 | ||
550 | dwarf_expr_eval (ctx, data, size); | |
87808bd6 JB |
551 | if (ctx->num_pieces > 0) |
552 | { | |
052b9502 NF |
553 | struct piece_closure *c; |
554 | struct frame_id frame_id = get_frame_id (frame); | |
555 | ||
6063c216 UW |
556 | c = allocate_piece_closure (ctx->num_pieces, ctx->pieces, |
557 | ctx->addr_size); | |
a2d33775 | 558 | retval = allocate_computed_value (type, &pieced_value_funcs, c); |
052b9502 | 559 | VALUE_FRAME_ID (retval) = frame_id; |
87808bd6 | 560 | } |
4c2df51b DJ |
561 | else |
562 | { | |
cec03d70 TT |
563 | switch (ctx->location) |
564 | { | |
565 | case DWARF_VALUE_REGISTER: | |
566 | { | |
567 | struct gdbarch *arch = get_frame_arch (frame); | |
568 | CORE_ADDR dwarf_regnum = dwarf_expr_fetch (ctx, 0); | |
569 | int gdb_regnum = gdbarch_dwarf2_reg_to_regnum (arch, dwarf_regnum); | |
9a619af0 | 570 | |
63b4f126 | 571 | if (gdb_regnum != -1) |
a2d33775 | 572 | retval = value_from_register (type, gdb_regnum, frame); |
63b4f126 | 573 | else |
a2d33775 JK |
574 | error (_("Unable to access DWARF register number %s"), |
575 | paddress (arch, dwarf_regnum)); | |
cec03d70 TT |
576 | } |
577 | break; | |
578 | ||
579 | case DWARF_VALUE_MEMORY: | |
580 | { | |
581 | CORE_ADDR address = dwarf_expr_fetch (ctx, 0); | |
44353522 | 582 | int in_stack_memory = dwarf_expr_fetch_in_stack_memory (ctx, 0); |
cec03d70 | 583 | |
a2d33775 | 584 | retval = allocate_value (type); |
cec03d70 TT |
585 | VALUE_LVAL (retval) = lval_memory; |
586 | set_value_lazy (retval, 1); | |
44353522 DE |
587 | if (in_stack_memory) |
588 | set_value_stack (retval, 1); | |
cec03d70 TT |
589 | set_value_address (retval, address); |
590 | } | |
591 | break; | |
592 | ||
593 | case DWARF_VALUE_STACK: | |
594 | { | |
cec03d70 TT |
595 | ULONGEST value = (ULONGEST) dwarf_expr_fetch (ctx, 0); |
596 | bfd_byte *contents; | |
597 | size_t n = ctx->addr_size; | |
598 | ||
a2d33775 | 599 | retval = allocate_value (type); |
cec03d70 | 600 | contents = value_contents_raw (retval); |
a2d33775 JK |
601 | if (n > TYPE_LENGTH (type)) |
602 | n = TYPE_LENGTH (type); | |
05566b3b TT |
603 | store_unsigned_integer (contents, n, |
604 | gdbarch_byte_order (ctx->gdbarch), | |
605 | value); | |
cec03d70 TT |
606 | } |
607 | break; | |
608 | ||
609 | case DWARF_VALUE_LITERAL: | |
610 | { | |
611 | bfd_byte *contents; | |
612 | size_t n = ctx->len; | |
613 | ||
a2d33775 | 614 | retval = allocate_value (type); |
cec03d70 | 615 | contents = value_contents_raw (retval); |
a2d33775 JK |
616 | if (n > TYPE_LENGTH (type)) |
617 | n = TYPE_LENGTH (type); | |
cec03d70 TT |
618 | memcpy (contents, ctx->data, n); |
619 | } | |
620 | break; | |
621 | ||
cb826367 TT |
622 | /* DWARF_VALUE_OPTIMIZED_OUT can't occur in this context -- |
623 | it can only be encountered when making a piece. */ | |
624 | case DWARF_VALUE_OPTIMIZED_OUT: | |
cec03d70 TT |
625 | default: |
626 | internal_error (__FILE__, __LINE__, _("invalid location type")); | |
627 | } | |
4c2df51b DJ |
628 | } |
629 | ||
42be36b3 CT |
630 | set_value_initialized (retval, ctx->initialized); |
631 | ||
4a227398 | 632 | do_cleanups (old_chain); |
4c2df51b DJ |
633 | |
634 | return retval; | |
635 | } | |
4c2df51b DJ |
636 | \f |
637 | /* Helper functions and baton for dwarf2_loc_desc_needs_frame. */ | |
638 | ||
639 | struct needs_frame_baton | |
640 | { | |
641 | int needs_frame; | |
642 | }; | |
643 | ||
644 | /* Reads from registers do require a frame. */ | |
645 | static CORE_ADDR | |
61fbb938 | 646 | needs_frame_read_reg (void *baton, int regnum) |
4c2df51b DJ |
647 | { |
648 | struct needs_frame_baton *nf_baton = baton; | |
9a619af0 | 649 | |
4c2df51b DJ |
650 | nf_baton->needs_frame = 1; |
651 | return 1; | |
652 | } | |
653 | ||
654 | /* Reads from memory do not require a frame. */ | |
655 | static void | |
852483bc | 656 | needs_frame_read_mem (void *baton, gdb_byte *buf, CORE_ADDR addr, size_t len) |
4c2df51b DJ |
657 | { |
658 | memset (buf, 0, len); | |
659 | } | |
660 | ||
661 | /* Frame-relative accesses do require a frame. */ | |
662 | static void | |
852483bc | 663 | needs_frame_frame_base (void *baton, gdb_byte **start, size_t * length) |
4c2df51b | 664 | { |
852483bc | 665 | static gdb_byte lit0 = DW_OP_lit0; |
4c2df51b DJ |
666 | struct needs_frame_baton *nf_baton = baton; |
667 | ||
668 | *start = &lit0; | |
669 | *length = 1; | |
670 | ||
671 | nf_baton->needs_frame = 1; | |
672 | } | |
673 | ||
e7802207 TT |
674 | /* CFA accesses require a frame. */ |
675 | ||
676 | static CORE_ADDR | |
677 | needs_frame_frame_cfa (void *baton) | |
678 | { | |
679 | struct needs_frame_baton *nf_baton = baton; | |
9a619af0 | 680 | |
e7802207 TT |
681 | nf_baton->needs_frame = 1; |
682 | return 1; | |
683 | } | |
684 | ||
4c2df51b DJ |
685 | /* Thread-local accesses do require a frame. */ |
686 | static CORE_ADDR | |
687 | needs_frame_tls_address (void *baton, CORE_ADDR offset) | |
688 | { | |
689 | struct needs_frame_baton *nf_baton = baton; | |
9a619af0 | 690 | |
4c2df51b DJ |
691 | nf_baton->needs_frame = 1; |
692 | return 1; | |
693 | } | |
694 | ||
695 | /* Return non-zero iff the location expression at DATA (length SIZE) | |
696 | requires a frame to evaluate. */ | |
697 | ||
698 | static int | |
ae0d2f24 UW |
699 | dwarf2_loc_desc_needs_frame (gdb_byte *data, unsigned short size, |
700 | struct dwarf2_per_cu_data *per_cu) | |
4c2df51b DJ |
701 | { |
702 | struct needs_frame_baton baton; | |
703 | struct dwarf_expr_context *ctx; | |
f630a401 | 704 | int in_reg; |
4a227398 | 705 | struct cleanup *old_chain; |
4c2df51b DJ |
706 | |
707 | baton.needs_frame = 0; | |
708 | ||
709 | ctx = new_dwarf_expr_context (); | |
4a227398 TT |
710 | old_chain = make_cleanup_free_dwarf_expr_context (ctx); |
711 | ||
f7fd4728 | 712 | ctx->gdbarch = get_objfile_arch (dwarf2_per_cu_objfile (per_cu)); |
ae0d2f24 | 713 | ctx->addr_size = dwarf2_per_cu_addr_size (per_cu); |
4c2df51b DJ |
714 | ctx->baton = &baton; |
715 | ctx->read_reg = needs_frame_read_reg; | |
716 | ctx->read_mem = needs_frame_read_mem; | |
717 | ctx->get_frame_base = needs_frame_frame_base; | |
e7802207 | 718 | ctx->get_frame_cfa = needs_frame_frame_cfa; |
4c2df51b DJ |
719 | ctx->get_tls_address = needs_frame_tls_address; |
720 | ||
721 | dwarf_expr_eval (ctx, data, size); | |
722 | ||
cec03d70 | 723 | in_reg = ctx->location == DWARF_VALUE_REGISTER; |
f630a401 | 724 | |
87808bd6 JB |
725 | if (ctx->num_pieces > 0) |
726 | { | |
727 | int i; | |
728 | ||
729 | /* If the location has several pieces, and any of them are in | |
730 | registers, then we will need a frame to fetch them from. */ | |
731 | for (i = 0; i < ctx->num_pieces; i++) | |
cec03d70 | 732 | if (ctx->pieces[i].location == DWARF_VALUE_REGISTER) |
87808bd6 JB |
733 | in_reg = 1; |
734 | } | |
735 | ||
4a227398 | 736 | do_cleanups (old_chain); |
4c2df51b | 737 | |
f630a401 | 738 | return baton.needs_frame || in_reg; |
4c2df51b DJ |
739 | } |
740 | ||
08922a10 SS |
741 | /* This struct keeps track of the pieces that make up a multi-location |
742 | object, for use in agent expression generation. It is | |
743 | superficially similar to struct dwarf_expr_piece, but | |
744 | dwarf_expr_piece is designed for use in immediate evaluation, and | |
745 | does not, for example, have a way to record both base register and | |
746 | offset. */ | |
747 | ||
748 | struct axs_var_loc | |
0d53c4c4 | 749 | { |
08922a10 SS |
750 | /* Memory vs register, etc */ |
751 | enum axs_lvalue_kind kind; | |
752 | ||
753 | /* If non-zero, number of bytes in this fragment */ | |
754 | unsigned bytes; | |
755 | ||
756 | /* (GDB-numbered) reg, or base reg if >= 0 */ | |
757 | int reg; | |
758 | ||
759 | /* offset from reg */ | |
760 | LONGEST offset; | |
761 | }; | |
762 | ||
763 | static gdb_byte * | |
764 | dwarf2_tracepoint_var_loc (struct symbol *symbol, | |
765 | struct agent_expr *ax, | |
766 | struct axs_var_loc *loc, | |
767 | struct gdbarch *gdbarch, | |
768 | gdb_byte *data, gdb_byte *end) | |
769 | { | |
770 | if (data[0] >= DW_OP_reg0 && data[0] <= DW_OP_reg31) | |
0d53c4c4 | 771 | { |
08922a10 SS |
772 | loc->kind = axs_lvalue_register; |
773 | loc->reg = gdbarch_dwarf2_reg_to_regnum (gdbarch, data[0] - DW_OP_reg0); | |
774 | data += 1; | |
0d53c4c4 DJ |
775 | } |
776 | else if (data[0] == DW_OP_regx) | |
777 | { | |
778 | ULONGEST reg; | |
9a619af0 | 779 | |
08922a10 SS |
780 | data = read_uleb128 (data + 1, end, ®); |
781 | loc->kind = axs_lvalue_register; | |
782 | loc->reg = gdbarch_dwarf2_reg_to_regnum (gdbarch, reg); | |
0d53c4c4 DJ |
783 | } |
784 | else if (data[0] == DW_OP_fbreg) | |
785 | { | |
0936ad1d SS |
786 | struct block *b; |
787 | struct symbol *framefunc; | |
788 | int frame_reg = 0; | |
0d53c4c4 | 789 | LONGEST frame_offset; |
0936ad1d SS |
790 | gdb_byte *base_data; |
791 | size_t base_size; | |
792 | LONGEST base_offset = 0; | |
793 | ||
794 | b = block_for_pc (ax->scope); | |
795 | ||
796 | if (!b) | |
797 | error (_("No block found for address")); | |
798 | ||
799 | framefunc = block_linkage_function (b); | |
800 | ||
801 | if (!framefunc) | |
802 | error (_("No function found for block")); | |
803 | ||
804 | dwarf_expr_frame_base_1 (framefunc, ax->scope, | |
805 | &base_data, &base_size); | |
806 | ||
08922a10 | 807 | if (base_data[0] >= DW_OP_breg0 && base_data[0] <= DW_OP_breg31) |
0936ad1d | 808 | { |
08922a10 SS |
809 | gdb_byte *buf_end; |
810 | ||
0936ad1d | 811 | frame_reg = base_data[0] - DW_OP_breg0; |
08922a10 SS |
812 | buf_end = read_sleb128 (base_data + 1, |
813 | base_data + base_size, &base_offset); | |
0936ad1d SS |
814 | if (buf_end != base_data + base_size) |
815 | error (_("Unexpected opcode after DW_OP_breg%u for symbol \"%s\"."), | |
816 | frame_reg, SYMBOL_PRINT_NAME (symbol)); | |
817 | } | |
08922a10 SS |
818 | else if (base_data[0] >= DW_OP_reg0 && base_data[0] <= DW_OP_reg31) |
819 | { | |
820 | /* The frame base is just the register, with no offset. */ | |
821 | frame_reg = base_data[0] - DW_OP_reg0; | |
822 | base_offset = 0; | |
823 | } | |
0936ad1d SS |
824 | else |
825 | { | |
826 | /* We don't know what to do with the frame base expression, | |
827 | so we can't trace this variable; give up. */ | |
08922a10 SS |
828 | error (_("Cannot generate expression to collect symbol \"%s\"; DWARF 2 encoding not handled, first opcode in base data is 0x%x."), |
829 | SYMBOL_PRINT_NAME (symbol), base_data[0]); | |
0936ad1d | 830 | } |
0d53c4c4 | 831 | |
08922a10 | 832 | data = read_sleb128 (data + 1, end, &frame_offset); |
4c2df51b | 833 | |
08922a10 SS |
834 | loc->kind = axs_lvalue_memory; |
835 | loc->reg = gdbarch_dwarf2_reg_to_regnum (gdbarch, frame_reg); | |
836 | loc->offset = base_offset + frame_offset; | |
9c238357 | 837 | } |
08922a10 | 838 | else if (data[0] >= DW_OP_breg0 && data[0] <= DW_OP_breg31) |
9c238357 RC |
839 | { |
840 | unsigned int reg; | |
841 | LONGEST offset; | |
9c238357 RC |
842 | |
843 | reg = data[0] - DW_OP_breg0; | |
08922a10 | 844 | data = read_sleb128 (data + 1, end, &offset); |
9c238357 | 845 | |
08922a10 SS |
846 | loc->kind = axs_lvalue_memory; |
847 | loc->reg = gdbarch_dwarf2_reg_to_regnum (gdbarch, reg); | |
848 | loc->offset = offset; | |
0d53c4c4 DJ |
849 | } |
850 | else | |
9c238357 RC |
851 | error (_("Unsupported DWARF opcode 0x%x in the location of \"%s\"."), |
852 | data[0], SYMBOL_PRINT_NAME (symbol)); | |
08922a10 SS |
853 | |
854 | return data; | |
0d53c4c4 | 855 | } |
08922a10 SS |
856 | |
857 | /* Given the location of a piece, issue bytecodes that will access it. */ | |
858 | ||
859 | static void | |
860 | dwarf2_tracepoint_var_access (struct agent_expr *ax, | |
861 | struct axs_value *value, | |
862 | struct axs_var_loc *loc) | |
863 | { | |
864 | value->kind = loc->kind; | |
865 | ||
866 | switch (loc->kind) | |
867 | { | |
868 | case axs_lvalue_register: | |
869 | value->u.reg = loc->reg; | |
870 | break; | |
871 | ||
872 | case axs_lvalue_memory: | |
873 | ax_reg (ax, loc->reg); | |
874 | if (loc->offset) | |
875 | { | |
876 | ax_const_l (ax, loc->offset); | |
877 | ax_simple (ax, aop_add); | |
878 | } | |
879 | break; | |
880 | ||
881 | default: | |
882 | internal_error (__FILE__, __LINE__, _("Unhandled value kind in dwarf2_tracepoint_var_access")); | |
883 | } | |
884 | } | |
885 | ||
886 | static void | |
887 | dwarf2_tracepoint_var_ref (struct symbol *symbol, struct gdbarch *gdbarch, | |
888 | struct agent_expr *ax, struct axs_value *value, | |
889 | gdb_byte *data, int size) | |
890 | { | |
891 | gdb_byte *end = data + size; | |
892 | enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); | |
893 | /* In practice, a variable is not going to be spread across | |
894 | dozens of registers or memory locations. If someone comes up | |
895 | with a real-world example, revisit this. */ | |
896 | #define MAX_FRAGS 16 | |
897 | struct axs_var_loc fragments[MAX_FRAGS]; | |
898 | int nfrags = 0, frag; | |
899 | int length = 0; | |
900 | int piece_ok = 0; | |
901 | int bad = 0; | |
902 | int first = 1; | |
903 | ||
904 | if (!data || size == 0) | |
905 | { | |
906 | value->optimized_out = 1; | |
907 | return; | |
908 | } | |
909 | ||
910 | while (data < end) | |
911 | { | |
912 | if (!piece_ok) | |
913 | { | |
914 | if (nfrags == MAX_FRAGS) | |
915 | error (_("Too many pieces in location for \"%s\"."), | |
916 | SYMBOL_PRINT_NAME (symbol)); | |
917 | ||
918 | fragments[nfrags].bytes = 0; | |
919 | data = dwarf2_tracepoint_var_loc (symbol, ax, &fragments[nfrags], | |
920 | gdbarch, data, end); | |
921 | nfrags++; | |
922 | piece_ok = 1; | |
923 | } | |
924 | else if (data[0] == DW_OP_piece) | |
925 | { | |
926 | ULONGEST bytes; | |
927 | ||
928 | data = read_uleb128 (data + 1, end, &bytes); | |
929 | /* Only deal with 4 byte fragments for now. */ | |
930 | if (bytes != 4) | |
931 | error (_("DW_OP_piece %s not supported in location for \"%s\"."), | |
932 | pulongest (bytes), SYMBOL_PRINT_NAME (symbol)); | |
933 | fragments[nfrags - 1].bytes = bytes; | |
934 | length += bytes; | |
935 | piece_ok = 0; | |
936 | } | |
937 | else | |
938 | { | |
939 | bad = 1; | |
940 | break; | |
941 | } | |
942 | } | |
943 | ||
944 | if (bad || data > end) | |
945 | error (_("Corrupted DWARF expression for \"%s\"."), | |
946 | SYMBOL_PRINT_NAME (symbol)); | |
947 | ||
948 | /* If single expression, no pieces, convert to external format. */ | |
949 | if (length == 0) | |
950 | { | |
951 | dwarf2_tracepoint_var_access (ax, value, &fragments[0]); | |
952 | return; | |
953 | } | |
954 | ||
955 | if (length != TYPE_LENGTH (value->type)) | |
956 | error (_("Inconsistent piece information for \"%s\"."), | |
957 | SYMBOL_PRINT_NAME (symbol)); | |
958 | ||
959 | /* Emit bytecodes to assemble the pieces into a single stack entry. */ | |
960 | ||
961 | for ((frag = (byte_order == BFD_ENDIAN_BIG ? 0 : nfrags - 1)); | |
962 | nfrags--; | |
963 | (frag += (byte_order == BFD_ENDIAN_BIG ? 1 : -1))) | |
964 | { | |
965 | if (!first) | |
966 | { | |
967 | /* shift the previous fragment up 32 bits */ | |
968 | ax_const_l (ax, 32); | |
969 | ax_simple (ax, aop_lsh); | |
970 | } | |
971 | ||
972 | dwarf2_tracepoint_var_access (ax, value, &fragments[frag]); | |
973 | ||
974 | switch (value->kind) | |
975 | { | |
976 | case axs_lvalue_register: | |
977 | ax_reg (ax, value->u.reg); | |
978 | break; | |
979 | ||
980 | case axs_lvalue_memory: | |
981 | { | |
982 | extern int trace_kludge; /* Ugh. */ | |
983 | ||
984 | gdb_assert (fragments[frag].bytes == 4); | |
985 | if (trace_kludge) | |
986 | ax_trace_quick (ax, 4); | |
987 | ax_simple (ax, aop_ref32); | |
988 | } | |
989 | break; | |
990 | } | |
991 | ||
992 | if (!first) | |
993 | { | |
994 | /* or the new fragment into the previous */ | |
995 | ax_zero_ext (ax, 32); | |
996 | ax_simple (ax, aop_bit_or); | |
997 | } | |
998 | first = 0; | |
999 | } | |
1000 | value->kind = axs_rvalue; | |
1001 | } | |
1002 | ||
4c2df51b DJ |
1003 | \f |
1004 | /* Return the value of SYMBOL in FRAME using the DWARF-2 expression | |
1005 | evaluator to calculate the location. */ | |
1006 | static struct value * | |
1007 | locexpr_read_variable (struct symbol *symbol, struct frame_info *frame) | |
1008 | { | |
1009 | struct dwarf2_locexpr_baton *dlbaton = SYMBOL_LOCATION_BATON (symbol); | |
1010 | struct value *val; | |
9a619af0 | 1011 | |
a2d33775 JK |
1012 | val = dwarf2_evaluate_loc_desc (SYMBOL_TYPE (symbol), frame, dlbaton->data, |
1013 | dlbaton->size, dlbaton->per_cu); | |
4c2df51b DJ |
1014 | |
1015 | return val; | |
1016 | } | |
1017 | ||
1018 | /* Return non-zero iff we need a frame to evaluate SYMBOL. */ | |
1019 | static int | |
1020 | locexpr_read_needs_frame (struct symbol *symbol) | |
1021 | { | |
1022 | struct dwarf2_locexpr_baton *dlbaton = SYMBOL_LOCATION_BATON (symbol); | |
9a619af0 | 1023 | |
ae0d2f24 UW |
1024 | return dwarf2_loc_desc_needs_frame (dlbaton->data, dlbaton->size, |
1025 | dlbaton->per_cu); | |
4c2df51b DJ |
1026 | } |
1027 | ||
08922a10 SS |
1028 | /* Describe a single piece of a location, returning an updated |
1029 | position in the bytecode sequence. */ | |
1030 | ||
1031 | static gdb_byte * | |
1032 | locexpr_describe_location_piece (struct symbol *symbol, struct ui_file *stream, | |
1033 | CORE_ADDR addr, struct objfile *objfile, | |
1034 | gdb_byte *data, int size, unsigned int addr_size) | |
4c2df51b | 1035 | { |
08922a10 SS |
1036 | struct gdbarch *gdbarch = get_objfile_arch (objfile); |
1037 | int regno; | |
1038 | ||
1039 | if (data[0] >= DW_OP_reg0 && data[0] <= DW_OP_reg31) | |
1040 | { | |
1041 | regno = gdbarch_dwarf2_reg_to_regnum (gdbarch, data[0] - DW_OP_reg0); | |
1042 | fprintf_filtered (stream, _("a variable in $%s"), | |
1043 | gdbarch_register_name (gdbarch, regno)); | |
1044 | data += 1; | |
1045 | } | |
1046 | else if (data[0] == DW_OP_regx) | |
1047 | { | |
1048 | ULONGEST reg; | |
4c2df51b | 1049 | |
08922a10 SS |
1050 | data = read_uleb128 (data + 1, data + size, ®); |
1051 | regno = gdbarch_dwarf2_reg_to_regnum (gdbarch, reg); | |
1052 | fprintf_filtered (stream, _("a variable in $%s"), | |
1053 | gdbarch_register_name (gdbarch, regno)); | |
1054 | } | |
1055 | else if (data[0] == DW_OP_fbreg) | |
4c2df51b | 1056 | { |
08922a10 SS |
1057 | struct block *b; |
1058 | struct symbol *framefunc; | |
1059 | int frame_reg = 0; | |
1060 | LONGEST frame_offset; | |
1061 | gdb_byte *base_data; | |
1062 | size_t base_size; | |
1063 | LONGEST base_offset = 0; | |
1064 | ||
1065 | b = block_for_pc (addr); | |
1066 | ||
1067 | if (!b) | |
1068 | error (_("No block found for address for symbol \"%s\"."), | |
1069 | SYMBOL_PRINT_NAME (symbol)); | |
1070 | ||
1071 | framefunc = block_linkage_function (b); | |
1072 | ||
1073 | if (!framefunc) | |
1074 | error (_("No function found for block for symbol \"%s\"."), | |
1075 | SYMBOL_PRINT_NAME (symbol)); | |
1076 | ||
1077 | dwarf_expr_frame_base_1 (framefunc, addr, &base_data, &base_size); | |
1078 | ||
1079 | if (base_data[0] >= DW_OP_breg0 && base_data[0] <= DW_OP_breg31) | |
1080 | { | |
1081 | gdb_byte *buf_end; | |
1082 | ||
1083 | frame_reg = base_data[0] - DW_OP_breg0; | |
1084 | buf_end = read_sleb128 (base_data + 1, | |
1085 | base_data + base_size, &base_offset); | |
1086 | if (buf_end != base_data + base_size) | |
1087 | error (_("Unexpected opcode after DW_OP_breg%u for symbol \"%s\"."), | |
1088 | frame_reg, SYMBOL_PRINT_NAME (symbol)); | |
1089 | } | |
1090 | else if (base_data[0] >= DW_OP_reg0 && base_data[0] <= DW_OP_reg31) | |
1091 | { | |
1092 | /* The frame base is just the register, with no offset. */ | |
1093 | frame_reg = base_data[0] - DW_OP_reg0; | |
1094 | base_offset = 0; | |
1095 | } | |
1096 | else | |
1097 | { | |
1098 | /* We don't know what to do with the frame base expression, | |
1099 | so we can't trace this variable; give up. */ | |
1100 | error (_("Cannot describe location of symbol \"%s\"; " | |
1101 | "DWARF 2 encoding not handled, " | |
1102 | "first opcode in base data is 0x%x."), | |
1103 | SYMBOL_PRINT_NAME (symbol), base_data[0]); | |
1104 | } | |
1105 | ||
1106 | regno = gdbarch_dwarf2_reg_to_regnum (gdbarch, frame_reg); | |
1107 | ||
1108 | data = read_sleb128 (data + 1, data + size, &frame_offset); | |
1109 | ||
1110 | fprintf_filtered (stream, _("a variable at frame base reg $%s offset %s+%s"), | |
1111 | gdbarch_register_name (gdbarch, regno), | |
1112 | plongest (base_offset), plongest (frame_offset)); | |
1113 | } | |
1114 | else if (data[0] >= DW_OP_breg0 && data[0] <= DW_OP_breg31) | |
1115 | { | |
1116 | LONGEST offset; | |
1117 | ||
1118 | regno = gdbarch_dwarf2_reg_to_regnum (gdbarch, data[0] - DW_OP_breg0); | |
1119 | ||
1120 | data = read_sleb128 (data + 1, data + size, &offset); | |
1121 | ||
4c2df51b | 1122 | fprintf_filtered (stream, |
08922a10 SS |
1123 | _("a variable at offset %s from base reg $%s"), |
1124 | plongest (offset), | |
5e2b427d | 1125 | gdbarch_register_name (gdbarch, regno)); |
4c2df51b DJ |
1126 | } |
1127 | ||
c3228f12 EZ |
1128 | /* The location expression for a TLS variable looks like this (on a |
1129 | 64-bit LE machine): | |
1130 | ||
1131 | DW_AT_location : 10 byte block: 3 4 0 0 0 0 0 0 0 e0 | |
1132 | (DW_OP_addr: 4; DW_OP_GNU_push_tls_address) | |
1133 | ||
1134 | 0x3 is the encoding for DW_OP_addr, which has an operand as long | |
1135 | as the size of an address on the target machine (here is 8 | |
1136 | bytes). 0xe0 is the encoding for DW_OP_GNU_push_tls_address. | |
1137 | The operand represents the offset at which the variable is within | |
1138 | the thread local storage. */ | |
1139 | ||
08922a10 SS |
1140 | else if (size > 1 |
1141 | && data[size - 1] == DW_OP_GNU_push_tls_address | |
1142 | && data[0] == DW_OP_addr) | |
1143 | { | |
1144 | CORE_ADDR offset = dwarf2_read_address (gdbarch, | |
1145 | data + 1, | |
1146 | data + size - 1, | |
1147 | addr_size); | |
9a619af0 | 1148 | |
08922a10 SS |
1149 | fprintf_filtered (stream, |
1150 | _("a thread-local variable at offset %s " | |
1151 | "in the thread-local storage for `%s'"), | |
1152 | paddress (gdbarch, offset), objfile->name); | |
1153 | ||
1154 | data += 1 + addr_size + 1; | |
1155 | } | |
1156 | else | |
1157 | fprintf_filtered (stream, | |
1158 | _("a variable with complex or multiple locations (DWARF2)")); | |
c3228f12 | 1159 | |
08922a10 | 1160 | return data; |
4c2df51b DJ |
1161 | } |
1162 | ||
08922a10 SS |
1163 | /* Describe a single location, which may in turn consist of multiple |
1164 | pieces. */ | |
a55cc764 | 1165 | |
08922a10 SS |
1166 | static void |
1167 | locexpr_describe_location_1 (struct symbol *symbol, CORE_ADDR addr, | |
1168 | struct ui_file *stream, gdb_byte *data, int size, | |
1169 | struct objfile *objfile, unsigned int addr_size) | |
1170 | { | |
1171 | gdb_byte *end = data + size; | |
1172 | int piece_done = 0, first_piece = 1, bad = 0; | |
1173 | ||
1174 | /* A multi-piece description consists of multiple sequences of bytes | |
1175 | each followed by DW_OP_piece + length of piece. */ | |
1176 | while (data < end) | |
1177 | { | |
1178 | if (!piece_done) | |
1179 | { | |
1180 | if (first_piece) | |
1181 | first_piece = 0; | |
1182 | else | |
1183 | fprintf_filtered (stream, _(", and ")); | |
1184 | ||
1185 | data = locexpr_describe_location_piece (symbol, stream, addr, objfile, | |
1186 | data, size, addr_size); | |
1187 | piece_done = 1; | |
1188 | } | |
1189 | else if (data[0] == DW_OP_piece) | |
1190 | { | |
1191 | ULONGEST bytes; | |
1192 | ||
1193 | data = read_uleb128 (data + 1, end, &bytes); | |
1194 | ||
1195 | fprintf_filtered (stream, _(" [%s-byte piece]"), pulongest (bytes)); | |
1196 | ||
1197 | piece_done = 0; | |
1198 | } | |
1199 | else | |
1200 | { | |
1201 | bad = 1; | |
1202 | break; | |
1203 | } | |
1204 | } | |
1205 | ||
1206 | if (bad || data > end) | |
1207 | error (_("Corrupted DWARF2 expression for \"%s\"."), | |
1208 | SYMBOL_PRINT_NAME (symbol)); | |
1209 | } | |
1210 | ||
1211 | /* Print a natural-language description of SYMBOL to STREAM. This | |
1212 | version is for a symbol with a single location. */ | |
a55cc764 | 1213 | |
08922a10 SS |
1214 | static void |
1215 | locexpr_describe_location (struct symbol *symbol, CORE_ADDR addr, | |
1216 | struct ui_file *stream) | |
1217 | { | |
1218 | struct dwarf2_locexpr_baton *dlbaton = SYMBOL_LOCATION_BATON (symbol); | |
1219 | struct objfile *objfile = dwarf2_per_cu_objfile (dlbaton->per_cu); | |
1220 | unsigned int addr_size = dwarf2_per_cu_addr_size (dlbaton->per_cu); | |
1221 | ||
1222 | locexpr_describe_location_1 (symbol, addr, stream, dlbaton->data, dlbaton->size, | |
1223 | objfile, addr_size); | |
1224 | } | |
1225 | ||
1226 | /* Describe the location of SYMBOL as an agent value in VALUE, generating | |
1227 | any necessary bytecode in AX. */ | |
a55cc764 | 1228 | |
0d53c4c4 | 1229 | static void |
505e835d UW |
1230 | locexpr_tracepoint_var_ref (struct symbol *symbol, struct gdbarch *gdbarch, |
1231 | struct agent_expr *ax, struct axs_value *value) | |
a55cc764 DJ |
1232 | { |
1233 | struct dwarf2_locexpr_baton *dlbaton = SYMBOL_LOCATION_BATON (symbol); | |
1234 | ||
505e835d UW |
1235 | dwarf2_tracepoint_var_ref (symbol, gdbarch, ax, value, |
1236 | dlbaton->data, dlbaton->size); | |
a55cc764 DJ |
1237 | } |
1238 | ||
4c2df51b DJ |
1239 | /* The set of location functions used with the DWARF-2 expression |
1240 | evaluator. */ | |
768a979c | 1241 | const struct symbol_computed_ops dwarf2_locexpr_funcs = { |
4c2df51b DJ |
1242 | locexpr_read_variable, |
1243 | locexpr_read_needs_frame, | |
1244 | locexpr_describe_location, | |
a55cc764 | 1245 | locexpr_tracepoint_var_ref |
4c2df51b | 1246 | }; |
0d53c4c4 DJ |
1247 | |
1248 | ||
1249 | /* Wrapper functions for location lists. These generally find | |
1250 | the appropriate location expression and call something above. */ | |
1251 | ||
1252 | /* Return the value of SYMBOL in FRAME using the DWARF-2 expression | |
1253 | evaluator to calculate the location. */ | |
1254 | static struct value * | |
1255 | loclist_read_variable (struct symbol *symbol, struct frame_info *frame) | |
1256 | { | |
1257 | struct dwarf2_loclist_baton *dlbaton = SYMBOL_LOCATION_BATON (symbol); | |
1258 | struct value *val; | |
852483bc | 1259 | gdb_byte *data; |
b6b08ebf | 1260 | size_t size; |
0d53c4c4 DJ |
1261 | |
1262 | data = find_location_expression (dlbaton, &size, | |
22c6caba JW |
1263 | frame ? get_frame_address_in_block (frame) |
1264 | : 0); | |
0d53c4c4 | 1265 | if (data == NULL) |
806048c6 DJ |
1266 | { |
1267 | val = allocate_value (SYMBOL_TYPE (symbol)); | |
1268 | VALUE_LVAL (val) = not_lval; | |
1269 | set_value_optimized_out (val, 1); | |
1270 | } | |
1271 | else | |
a2d33775 | 1272 | val = dwarf2_evaluate_loc_desc (SYMBOL_TYPE (symbol), frame, data, size, |
ae0d2f24 | 1273 | dlbaton->per_cu); |
0d53c4c4 DJ |
1274 | |
1275 | return val; | |
1276 | } | |
1277 | ||
1278 | /* Return non-zero iff we need a frame to evaluate SYMBOL. */ | |
1279 | static int | |
1280 | loclist_read_needs_frame (struct symbol *symbol) | |
1281 | { | |
1282 | /* If there's a location list, then assume we need to have a frame | |
1283 | to choose the appropriate location expression. With tracking of | |
1284 | global variables this is not necessarily true, but such tracking | |
1285 | is disabled in GCC at the moment until we figure out how to | |
1286 | represent it. */ | |
1287 | ||
1288 | return 1; | |
1289 | } | |
1290 | ||
08922a10 SS |
1291 | /* Print a natural-language description of SYMBOL to STREAM. This |
1292 | version applies when there is a list of different locations, each | |
1293 | with a specified address range. */ | |
1294 | ||
1295 | static void | |
1296 | loclist_describe_location (struct symbol *symbol, CORE_ADDR addr, | |
1297 | struct ui_file *stream) | |
0d53c4c4 | 1298 | { |
08922a10 SS |
1299 | struct dwarf2_loclist_baton *dlbaton = SYMBOL_LOCATION_BATON (symbol); |
1300 | CORE_ADDR low, high; | |
1301 | gdb_byte *loc_ptr, *buf_end; | |
1302 | int length, first = 1; | |
1303 | struct objfile *objfile = dwarf2_per_cu_objfile (dlbaton->per_cu); | |
1304 | struct gdbarch *gdbarch = get_objfile_arch (objfile); | |
1305 | enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); | |
1306 | unsigned int addr_size = dwarf2_per_cu_addr_size (dlbaton->per_cu); | |
1307 | CORE_ADDR base_mask = ~(~(CORE_ADDR)1 << (addr_size * 8 - 1)); | |
1308 | /* Adjust base_address for relocatable objects. */ | |
1309 | CORE_ADDR base_offset = ANOFFSET (objfile->section_offsets, | |
1310 | SECT_OFF_TEXT (objfile)); | |
1311 | CORE_ADDR base_address = dlbaton->base_address + base_offset; | |
1312 | ||
1313 | loc_ptr = dlbaton->data; | |
1314 | buf_end = dlbaton->data + dlbaton->size; | |
1315 | ||
1316 | fprintf_filtered (stream, _("multi-location (")); | |
1317 | ||
1318 | /* Iterate through locations until we run out. */ | |
1319 | while (1) | |
1320 | { | |
1321 | if (buf_end - loc_ptr < 2 * addr_size) | |
1322 | error (_("Corrupted DWARF expression for symbol \"%s\"."), | |
1323 | SYMBOL_PRINT_NAME (symbol)); | |
1324 | ||
1325 | low = extract_unsigned_integer (loc_ptr, addr_size, byte_order); | |
1326 | loc_ptr += addr_size; | |
1327 | ||
1328 | /* A base-address-selection entry. */ | |
1329 | if (low == base_mask) | |
1330 | { | |
1331 | base_address = dwarf2_read_address (gdbarch, | |
1332 | loc_ptr, buf_end, addr_size); | |
1333 | fprintf_filtered (stream, _("[base address %s]"), | |
1334 | paddress (gdbarch, base_address)); | |
1335 | loc_ptr += addr_size; | |
1336 | continue; | |
1337 | } | |
1338 | ||
1339 | high = extract_unsigned_integer (loc_ptr, addr_size, byte_order); | |
1340 | loc_ptr += addr_size; | |
1341 | ||
1342 | /* An end-of-list entry. */ | |
1343 | if (low == 0 && high == 0) | |
1344 | { | |
1345 | /* Indicate the end of the list, for readability. */ | |
1346 | fprintf_filtered (stream, _(")")); | |
1347 | return; | |
1348 | } | |
1349 | ||
1350 | /* Otherwise, a location expression entry. */ | |
1351 | low += base_address; | |
1352 | high += base_address; | |
1353 | ||
1354 | length = extract_unsigned_integer (loc_ptr, 2, byte_order); | |
1355 | loc_ptr += 2; | |
1356 | ||
1357 | /* Separate the different locations with a semicolon. */ | |
1358 | if (first) | |
1359 | first = 0; | |
1360 | else | |
1361 | fprintf_filtered (stream, _("; ")); | |
1362 | ||
1363 | /* (It would improve readability to print only the minimum | |
1364 | necessary digits of the second number of the range.) */ | |
1365 | fprintf_filtered (stream, _("range %s-%s, "), | |
1366 | paddress (gdbarch, low), paddress (gdbarch, high)); | |
1367 | ||
1368 | /* Now describe this particular location. */ | |
1369 | locexpr_describe_location_1 (symbol, low, stream, loc_ptr, length, | |
1370 | objfile, addr_size); | |
1371 | ||
1372 | loc_ptr += length; | |
1373 | } | |
0d53c4c4 DJ |
1374 | } |
1375 | ||
1376 | /* Describe the location of SYMBOL as an agent value in VALUE, generating | |
1377 | any necessary bytecode in AX. */ | |
1378 | static void | |
505e835d UW |
1379 | loclist_tracepoint_var_ref (struct symbol *symbol, struct gdbarch *gdbarch, |
1380 | struct agent_expr *ax, struct axs_value *value) | |
0d53c4c4 DJ |
1381 | { |
1382 | struct dwarf2_loclist_baton *dlbaton = SYMBOL_LOCATION_BATON (symbol); | |
852483bc | 1383 | gdb_byte *data; |
b6b08ebf | 1384 | size_t size; |
0d53c4c4 DJ |
1385 | |
1386 | data = find_location_expression (dlbaton, &size, ax->scope); | |
0d53c4c4 | 1387 | |
505e835d | 1388 | dwarf2_tracepoint_var_ref (symbol, gdbarch, ax, value, data, size); |
0d53c4c4 DJ |
1389 | } |
1390 | ||
1391 | /* The set of location functions used with the DWARF-2 expression | |
1392 | evaluator and location lists. */ | |
768a979c | 1393 | const struct symbol_computed_ops dwarf2_loclist_funcs = { |
0d53c4c4 DJ |
1394 | loclist_read_variable, |
1395 | loclist_read_needs_frame, | |
1396 | loclist_describe_location, | |
1397 | loclist_tracepoint_var_ref | |
1398 | }; |