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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; | |
267 | gdb_byte *contents; | |
268 | struct piece_closure *c = (struct piece_closure *) value_computed_closure (v); | |
269 | struct frame_info *frame = frame_find_by_id (VALUE_FRAME_ID (v)); | |
270 | ||
271 | contents = value_contents_raw (v); | |
272 | for (i = 0; i < c->n_pieces; i++) | |
273 | { | |
274 | struct dwarf_expr_piece *p = &c->pieces[i]; | |
9a619af0 | 275 | |
cec03d70 | 276 | switch (p->location) |
052b9502 | 277 | { |
cec03d70 TT |
278 | case DWARF_VALUE_REGISTER: |
279 | { | |
280 | struct gdbarch *arch = get_frame_arch (frame); | |
cec03d70 | 281 | int gdb_regnum = gdbarch_dwarf2_reg_to_regnum (arch, |
44353522 | 282 | p->v.expr.value); |
dcbf108f UW |
283 | int reg_offset = 0; |
284 | ||
285 | if (gdbarch_byte_order (arch) == BFD_ENDIAN_BIG | |
286 | && p->size < register_size (arch, gdb_regnum)) | |
287 | /* Big-endian, and we want less than full size. */ | |
288 | reg_offset = register_size (arch, gdb_regnum) - p->size; | |
289 | ||
63b4f126 MGD |
290 | if (gdb_regnum != -1) |
291 | { | |
292 | get_frame_register_bytes (frame, gdb_regnum, reg_offset, | |
293 | p->size, contents + offset); | |
294 | } | |
295 | else | |
296 | { | |
297 | error (_("Unable to access DWARF register number %s"), | |
298 | paddress (arch, p->v.expr.value)); | |
299 | } | |
cec03d70 TT |
300 | } |
301 | break; | |
302 | ||
303 | case DWARF_VALUE_MEMORY: | |
44353522 DE |
304 | if (p->v.expr.in_stack_memory) |
305 | read_stack (p->v.expr.value, contents + offset, p->size); | |
306 | else | |
307 | read_memory (p->v.expr.value, contents + offset, p->size); | |
cec03d70 TT |
308 | break; |
309 | ||
310 | case DWARF_VALUE_STACK: | |
311 | { | |
6063c216 UW |
312 | struct gdbarch *gdbarch = get_type_arch (value_type (v)); |
313 | size_t n = p->size; | |
9a619af0 | 314 | |
6063c216 UW |
315 | if (n > c->addr_size) |
316 | n = c->addr_size; | |
05566b3b | 317 | store_unsigned_integer (contents + offset, n, |
6063c216 | 318 | gdbarch_byte_order (gdbarch), |
05566b3b | 319 | p->v.expr.value); |
cec03d70 TT |
320 | } |
321 | break; | |
322 | ||
323 | case DWARF_VALUE_LITERAL: | |
324 | { | |
325 | size_t n = p->size; | |
9a619af0 | 326 | |
cec03d70 TT |
327 | if (n > p->v.literal.length) |
328 | n = p->v.literal.length; | |
329 | memcpy (contents + offset, p->v.literal.data, n); | |
330 | } | |
331 | break; | |
332 | ||
333 | default: | |
334 | internal_error (__FILE__, __LINE__, _("invalid location type")); | |
052b9502 NF |
335 | } |
336 | offset += p->size; | |
337 | } | |
338 | } | |
339 | ||
340 | static void | |
341 | write_pieced_value (struct value *to, struct value *from) | |
342 | { | |
343 | int i; | |
344 | long offset = 0; | |
345 | gdb_byte *contents; | |
346 | struct piece_closure *c = (struct piece_closure *) value_computed_closure (to); | |
347 | struct frame_info *frame = frame_find_by_id (VALUE_FRAME_ID (to)); | |
348 | ||
349 | if (frame == NULL) | |
350 | { | |
351 | set_value_optimized_out (to, 1); | |
352 | return; | |
353 | } | |
354 | ||
355 | contents = value_contents_raw (from); | |
356 | for (i = 0; i < c->n_pieces; i++) | |
357 | { | |
358 | struct dwarf_expr_piece *p = &c->pieces[i]; | |
9a619af0 | 359 | |
cec03d70 | 360 | switch (p->location) |
052b9502 | 361 | { |
cec03d70 TT |
362 | case DWARF_VALUE_REGISTER: |
363 | { | |
364 | struct gdbarch *arch = get_frame_arch (frame); | |
44353522 | 365 | int gdb_regnum = gdbarch_dwarf2_reg_to_regnum (arch, p->v.expr.value); |
dcbf108f UW |
366 | int reg_offset = 0; |
367 | ||
368 | if (gdbarch_byte_order (arch) == BFD_ENDIAN_BIG | |
369 | && p->size < register_size (arch, gdb_regnum)) | |
370 | /* Big-endian, and we want less than full size. */ | |
371 | reg_offset = register_size (arch, gdb_regnum) - p->size; | |
372 | ||
63b4f126 MGD |
373 | if (gdb_regnum != -1) |
374 | { | |
375 | put_frame_register_bytes (frame, gdb_regnum, reg_offset, | |
376 | p->size, contents + offset); | |
377 | } | |
378 | else | |
379 | { | |
380 | error (_("Unable to write to DWARF register number %s"), | |
381 | paddress (arch, p->v.expr.value)); | |
382 | } | |
cec03d70 TT |
383 | } |
384 | break; | |
385 | case DWARF_VALUE_MEMORY: | |
44353522 | 386 | write_memory (p->v.expr.value, contents + offset, p->size); |
cec03d70 TT |
387 | break; |
388 | default: | |
389 | set_value_optimized_out (to, 1); | |
390 | return; | |
052b9502 NF |
391 | } |
392 | offset += p->size; | |
393 | } | |
394 | } | |
395 | ||
396 | static void * | |
397 | copy_pieced_value_closure (struct value *v) | |
398 | { | |
399 | struct piece_closure *c = (struct piece_closure *) value_computed_closure (v); | |
400 | ||
6063c216 | 401 | return allocate_piece_closure (c->n_pieces, c->pieces, c->addr_size); |
052b9502 NF |
402 | } |
403 | ||
404 | static void | |
405 | free_pieced_value_closure (struct value *v) | |
406 | { | |
407 | struct piece_closure *c = (struct piece_closure *) value_computed_closure (v); | |
408 | ||
409 | xfree (c->pieces); | |
410 | xfree (c); | |
411 | } | |
412 | ||
413 | /* Functions for accessing a variable described by DW_OP_piece. */ | |
414 | static struct lval_funcs pieced_value_funcs = { | |
415 | read_pieced_value, | |
416 | write_pieced_value, | |
417 | copy_pieced_value_closure, | |
418 | free_pieced_value_closure | |
419 | }; | |
420 | ||
4c2df51b | 421 | /* Evaluate a location description, starting at DATA and with length |
a2d33775 | 422 | SIZE, to find the current location of variable of TYPE in the context |
4c2df51b | 423 | of FRAME. */ |
a2d33775 | 424 | |
4c2df51b | 425 | static struct value * |
a2d33775 | 426 | dwarf2_evaluate_loc_desc (struct type *type, struct frame_info *frame, |
852483bc | 427 | gdb_byte *data, unsigned short size, |
ae0d2f24 | 428 | struct dwarf2_per_cu_data *per_cu) |
4c2df51b | 429 | { |
4c2df51b DJ |
430 | struct value *retval; |
431 | struct dwarf_expr_baton baton; | |
432 | struct dwarf_expr_context *ctx; | |
4a227398 | 433 | struct cleanup *old_chain; |
4c2df51b | 434 | |
0d53c4c4 DJ |
435 | if (size == 0) |
436 | { | |
a2d33775 | 437 | retval = allocate_value (type); |
0d53c4c4 | 438 | VALUE_LVAL (retval) = not_lval; |
feb13ab0 | 439 | set_value_optimized_out (retval, 1); |
10fb19b6 | 440 | return retval; |
0d53c4c4 DJ |
441 | } |
442 | ||
4c2df51b | 443 | baton.frame = frame; |
ae0d2f24 | 444 | baton.objfile = dwarf2_per_cu_objfile (per_cu); |
4c2df51b DJ |
445 | |
446 | ctx = new_dwarf_expr_context (); | |
4a227398 TT |
447 | old_chain = make_cleanup_free_dwarf_expr_context (ctx); |
448 | ||
f7fd4728 | 449 | ctx->gdbarch = get_objfile_arch (baton.objfile); |
ae0d2f24 | 450 | ctx->addr_size = dwarf2_per_cu_addr_size (per_cu); |
4c2df51b DJ |
451 | ctx->baton = &baton; |
452 | ctx->read_reg = dwarf_expr_read_reg; | |
453 | ctx->read_mem = dwarf_expr_read_mem; | |
454 | ctx->get_frame_base = dwarf_expr_frame_base; | |
e7802207 | 455 | ctx->get_frame_cfa = dwarf_expr_frame_cfa; |
4c2df51b DJ |
456 | ctx->get_tls_address = dwarf_expr_tls_address; |
457 | ||
458 | dwarf_expr_eval (ctx, data, size); | |
87808bd6 JB |
459 | if (ctx->num_pieces > 0) |
460 | { | |
052b9502 NF |
461 | struct piece_closure *c; |
462 | struct frame_id frame_id = get_frame_id (frame); | |
463 | ||
6063c216 UW |
464 | c = allocate_piece_closure (ctx->num_pieces, ctx->pieces, |
465 | ctx->addr_size); | |
a2d33775 | 466 | retval = allocate_computed_value (type, &pieced_value_funcs, c); |
052b9502 | 467 | VALUE_FRAME_ID (retval) = frame_id; |
87808bd6 | 468 | } |
4c2df51b DJ |
469 | else |
470 | { | |
cec03d70 TT |
471 | switch (ctx->location) |
472 | { | |
473 | case DWARF_VALUE_REGISTER: | |
474 | { | |
475 | struct gdbarch *arch = get_frame_arch (frame); | |
476 | CORE_ADDR dwarf_regnum = dwarf_expr_fetch (ctx, 0); | |
477 | int gdb_regnum = gdbarch_dwarf2_reg_to_regnum (arch, dwarf_regnum); | |
9a619af0 | 478 | |
63b4f126 | 479 | if (gdb_regnum != -1) |
a2d33775 | 480 | retval = value_from_register (type, gdb_regnum, frame); |
63b4f126 | 481 | else |
a2d33775 JK |
482 | error (_("Unable to access DWARF register number %s"), |
483 | paddress (arch, dwarf_regnum)); | |
cec03d70 TT |
484 | } |
485 | break; | |
486 | ||
487 | case DWARF_VALUE_MEMORY: | |
488 | { | |
489 | CORE_ADDR address = dwarf_expr_fetch (ctx, 0); | |
44353522 | 490 | int in_stack_memory = dwarf_expr_fetch_in_stack_memory (ctx, 0); |
cec03d70 | 491 | |
a2d33775 | 492 | retval = allocate_value (type); |
cec03d70 TT |
493 | VALUE_LVAL (retval) = lval_memory; |
494 | set_value_lazy (retval, 1); | |
44353522 DE |
495 | if (in_stack_memory) |
496 | set_value_stack (retval, 1); | |
cec03d70 TT |
497 | set_value_address (retval, address); |
498 | } | |
499 | break; | |
500 | ||
501 | case DWARF_VALUE_STACK: | |
502 | { | |
cec03d70 TT |
503 | ULONGEST value = (ULONGEST) dwarf_expr_fetch (ctx, 0); |
504 | bfd_byte *contents; | |
505 | size_t n = ctx->addr_size; | |
506 | ||
a2d33775 | 507 | retval = allocate_value (type); |
cec03d70 | 508 | contents = value_contents_raw (retval); |
a2d33775 JK |
509 | if (n > TYPE_LENGTH (type)) |
510 | n = TYPE_LENGTH (type); | |
05566b3b TT |
511 | store_unsigned_integer (contents, n, |
512 | gdbarch_byte_order (ctx->gdbarch), | |
513 | value); | |
cec03d70 TT |
514 | } |
515 | break; | |
516 | ||
517 | case DWARF_VALUE_LITERAL: | |
518 | { | |
519 | bfd_byte *contents; | |
520 | size_t n = ctx->len; | |
521 | ||
a2d33775 | 522 | retval = allocate_value (type); |
cec03d70 | 523 | contents = value_contents_raw (retval); |
a2d33775 JK |
524 | if (n > TYPE_LENGTH (type)) |
525 | n = TYPE_LENGTH (type); | |
cec03d70 TT |
526 | memcpy (contents, ctx->data, n); |
527 | } | |
528 | break; | |
529 | ||
530 | default: | |
531 | internal_error (__FILE__, __LINE__, _("invalid location type")); | |
532 | } | |
4c2df51b DJ |
533 | } |
534 | ||
42be36b3 CT |
535 | set_value_initialized (retval, ctx->initialized); |
536 | ||
4a227398 | 537 | do_cleanups (old_chain); |
4c2df51b DJ |
538 | |
539 | return retval; | |
540 | } | |
4c2df51b DJ |
541 | \f |
542 | /* Helper functions and baton for dwarf2_loc_desc_needs_frame. */ | |
543 | ||
544 | struct needs_frame_baton | |
545 | { | |
546 | int needs_frame; | |
547 | }; | |
548 | ||
549 | /* Reads from registers do require a frame. */ | |
550 | static CORE_ADDR | |
61fbb938 | 551 | needs_frame_read_reg (void *baton, int regnum) |
4c2df51b DJ |
552 | { |
553 | struct needs_frame_baton *nf_baton = baton; | |
9a619af0 | 554 | |
4c2df51b DJ |
555 | nf_baton->needs_frame = 1; |
556 | return 1; | |
557 | } | |
558 | ||
559 | /* Reads from memory do not require a frame. */ | |
560 | static void | |
852483bc | 561 | needs_frame_read_mem (void *baton, gdb_byte *buf, CORE_ADDR addr, size_t len) |
4c2df51b DJ |
562 | { |
563 | memset (buf, 0, len); | |
564 | } | |
565 | ||
566 | /* Frame-relative accesses do require a frame. */ | |
567 | static void | |
852483bc | 568 | needs_frame_frame_base (void *baton, gdb_byte **start, size_t * length) |
4c2df51b | 569 | { |
852483bc | 570 | static gdb_byte lit0 = DW_OP_lit0; |
4c2df51b DJ |
571 | struct needs_frame_baton *nf_baton = baton; |
572 | ||
573 | *start = &lit0; | |
574 | *length = 1; | |
575 | ||
576 | nf_baton->needs_frame = 1; | |
577 | } | |
578 | ||
e7802207 TT |
579 | /* CFA accesses require a frame. */ |
580 | ||
581 | static CORE_ADDR | |
582 | needs_frame_frame_cfa (void *baton) | |
583 | { | |
584 | struct needs_frame_baton *nf_baton = baton; | |
9a619af0 | 585 | |
e7802207 TT |
586 | nf_baton->needs_frame = 1; |
587 | return 1; | |
588 | } | |
589 | ||
4c2df51b DJ |
590 | /* Thread-local accesses do require a frame. */ |
591 | static CORE_ADDR | |
592 | needs_frame_tls_address (void *baton, CORE_ADDR offset) | |
593 | { | |
594 | struct needs_frame_baton *nf_baton = baton; | |
9a619af0 | 595 | |
4c2df51b DJ |
596 | nf_baton->needs_frame = 1; |
597 | return 1; | |
598 | } | |
599 | ||
600 | /* Return non-zero iff the location expression at DATA (length SIZE) | |
601 | requires a frame to evaluate. */ | |
602 | ||
603 | static int | |
ae0d2f24 UW |
604 | dwarf2_loc_desc_needs_frame (gdb_byte *data, unsigned short size, |
605 | struct dwarf2_per_cu_data *per_cu) | |
4c2df51b DJ |
606 | { |
607 | struct needs_frame_baton baton; | |
608 | struct dwarf_expr_context *ctx; | |
f630a401 | 609 | int in_reg; |
4a227398 | 610 | struct cleanup *old_chain; |
4c2df51b DJ |
611 | |
612 | baton.needs_frame = 0; | |
613 | ||
614 | ctx = new_dwarf_expr_context (); | |
4a227398 TT |
615 | old_chain = make_cleanup_free_dwarf_expr_context (ctx); |
616 | ||
f7fd4728 | 617 | ctx->gdbarch = get_objfile_arch (dwarf2_per_cu_objfile (per_cu)); |
ae0d2f24 | 618 | ctx->addr_size = dwarf2_per_cu_addr_size (per_cu); |
4c2df51b DJ |
619 | ctx->baton = &baton; |
620 | ctx->read_reg = needs_frame_read_reg; | |
621 | ctx->read_mem = needs_frame_read_mem; | |
622 | ctx->get_frame_base = needs_frame_frame_base; | |
e7802207 | 623 | ctx->get_frame_cfa = needs_frame_frame_cfa; |
4c2df51b DJ |
624 | ctx->get_tls_address = needs_frame_tls_address; |
625 | ||
626 | dwarf_expr_eval (ctx, data, size); | |
627 | ||
cec03d70 | 628 | in_reg = ctx->location == DWARF_VALUE_REGISTER; |
f630a401 | 629 | |
87808bd6 JB |
630 | if (ctx->num_pieces > 0) |
631 | { | |
632 | int i; | |
633 | ||
634 | /* If the location has several pieces, and any of them are in | |
635 | registers, then we will need a frame to fetch them from. */ | |
636 | for (i = 0; i < ctx->num_pieces; i++) | |
cec03d70 | 637 | if (ctx->pieces[i].location == DWARF_VALUE_REGISTER) |
87808bd6 JB |
638 | in_reg = 1; |
639 | } | |
640 | ||
4a227398 | 641 | do_cleanups (old_chain); |
4c2df51b | 642 | |
f630a401 | 643 | return baton.needs_frame || in_reg; |
4c2df51b DJ |
644 | } |
645 | ||
08922a10 SS |
646 | /* This struct keeps track of the pieces that make up a multi-location |
647 | object, for use in agent expression generation. It is | |
648 | superficially similar to struct dwarf_expr_piece, but | |
649 | dwarf_expr_piece is designed for use in immediate evaluation, and | |
650 | does not, for example, have a way to record both base register and | |
651 | offset. */ | |
652 | ||
653 | struct axs_var_loc | |
0d53c4c4 | 654 | { |
08922a10 SS |
655 | /* Memory vs register, etc */ |
656 | enum axs_lvalue_kind kind; | |
657 | ||
658 | /* If non-zero, number of bytes in this fragment */ | |
659 | unsigned bytes; | |
660 | ||
661 | /* (GDB-numbered) reg, or base reg if >= 0 */ | |
662 | int reg; | |
663 | ||
664 | /* offset from reg */ | |
665 | LONGEST offset; | |
666 | }; | |
667 | ||
668 | static gdb_byte * | |
669 | dwarf2_tracepoint_var_loc (struct symbol *symbol, | |
670 | struct agent_expr *ax, | |
671 | struct axs_var_loc *loc, | |
672 | struct gdbarch *gdbarch, | |
673 | gdb_byte *data, gdb_byte *end) | |
674 | { | |
675 | if (data[0] >= DW_OP_reg0 && data[0] <= DW_OP_reg31) | |
0d53c4c4 | 676 | { |
08922a10 SS |
677 | loc->kind = axs_lvalue_register; |
678 | loc->reg = gdbarch_dwarf2_reg_to_regnum (gdbarch, data[0] - DW_OP_reg0); | |
679 | data += 1; | |
0d53c4c4 DJ |
680 | } |
681 | else if (data[0] == DW_OP_regx) | |
682 | { | |
683 | ULONGEST reg; | |
9a619af0 | 684 | |
08922a10 SS |
685 | data = read_uleb128 (data + 1, end, ®); |
686 | loc->kind = axs_lvalue_register; | |
687 | loc->reg = gdbarch_dwarf2_reg_to_regnum (gdbarch, reg); | |
0d53c4c4 DJ |
688 | } |
689 | else if (data[0] == DW_OP_fbreg) | |
690 | { | |
0936ad1d SS |
691 | struct block *b; |
692 | struct symbol *framefunc; | |
693 | int frame_reg = 0; | |
0d53c4c4 | 694 | LONGEST frame_offset; |
0936ad1d SS |
695 | gdb_byte *base_data; |
696 | size_t base_size; | |
697 | LONGEST base_offset = 0; | |
698 | ||
699 | b = block_for_pc (ax->scope); | |
700 | ||
701 | if (!b) | |
702 | error (_("No block found for address")); | |
703 | ||
704 | framefunc = block_linkage_function (b); | |
705 | ||
706 | if (!framefunc) | |
707 | error (_("No function found for block")); | |
708 | ||
709 | dwarf_expr_frame_base_1 (framefunc, ax->scope, | |
710 | &base_data, &base_size); | |
711 | ||
08922a10 | 712 | if (base_data[0] >= DW_OP_breg0 && base_data[0] <= DW_OP_breg31) |
0936ad1d | 713 | { |
08922a10 SS |
714 | gdb_byte *buf_end; |
715 | ||
0936ad1d | 716 | frame_reg = base_data[0] - DW_OP_breg0; |
08922a10 SS |
717 | buf_end = read_sleb128 (base_data + 1, |
718 | base_data + base_size, &base_offset); | |
0936ad1d SS |
719 | if (buf_end != base_data + base_size) |
720 | error (_("Unexpected opcode after DW_OP_breg%u for symbol \"%s\"."), | |
721 | frame_reg, SYMBOL_PRINT_NAME (symbol)); | |
722 | } | |
08922a10 SS |
723 | else if (base_data[0] >= DW_OP_reg0 && base_data[0] <= DW_OP_reg31) |
724 | { | |
725 | /* The frame base is just the register, with no offset. */ | |
726 | frame_reg = base_data[0] - DW_OP_reg0; | |
727 | base_offset = 0; | |
728 | } | |
0936ad1d SS |
729 | else |
730 | { | |
731 | /* We don't know what to do with the frame base expression, | |
732 | so we can't trace this variable; give up. */ | |
08922a10 SS |
733 | error (_("Cannot generate expression to collect symbol \"%s\"; DWARF 2 encoding not handled, first opcode in base data is 0x%x."), |
734 | SYMBOL_PRINT_NAME (symbol), base_data[0]); | |
0936ad1d | 735 | } |
0d53c4c4 | 736 | |
08922a10 | 737 | data = read_sleb128 (data + 1, end, &frame_offset); |
4c2df51b | 738 | |
08922a10 SS |
739 | loc->kind = axs_lvalue_memory; |
740 | loc->reg = gdbarch_dwarf2_reg_to_regnum (gdbarch, frame_reg); | |
741 | loc->offset = base_offset + frame_offset; | |
9c238357 | 742 | } |
08922a10 | 743 | else if (data[0] >= DW_OP_breg0 && data[0] <= DW_OP_breg31) |
9c238357 RC |
744 | { |
745 | unsigned int reg; | |
746 | LONGEST offset; | |
9c238357 RC |
747 | |
748 | reg = data[0] - DW_OP_breg0; | |
08922a10 | 749 | data = read_sleb128 (data + 1, end, &offset); |
9c238357 | 750 | |
08922a10 SS |
751 | loc->kind = axs_lvalue_memory; |
752 | loc->reg = gdbarch_dwarf2_reg_to_regnum (gdbarch, reg); | |
753 | loc->offset = offset; | |
0d53c4c4 DJ |
754 | } |
755 | else | |
9c238357 RC |
756 | error (_("Unsupported DWARF opcode 0x%x in the location of \"%s\"."), |
757 | data[0], SYMBOL_PRINT_NAME (symbol)); | |
08922a10 SS |
758 | |
759 | return data; | |
0d53c4c4 | 760 | } |
08922a10 SS |
761 | |
762 | /* Given the location of a piece, issue bytecodes that will access it. */ | |
763 | ||
764 | static void | |
765 | dwarf2_tracepoint_var_access (struct agent_expr *ax, | |
766 | struct axs_value *value, | |
767 | struct axs_var_loc *loc) | |
768 | { | |
769 | value->kind = loc->kind; | |
770 | ||
771 | switch (loc->kind) | |
772 | { | |
773 | case axs_lvalue_register: | |
774 | value->u.reg = loc->reg; | |
775 | break; | |
776 | ||
777 | case axs_lvalue_memory: | |
778 | ax_reg (ax, loc->reg); | |
779 | if (loc->offset) | |
780 | { | |
781 | ax_const_l (ax, loc->offset); | |
782 | ax_simple (ax, aop_add); | |
783 | } | |
784 | break; | |
785 | ||
786 | default: | |
787 | internal_error (__FILE__, __LINE__, _("Unhandled value kind in dwarf2_tracepoint_var_access")); | |
788 | } | |
789 | } | |
790 | ||
791 | static void | |
792 | dwarf2_tracepoint_var_ref (struct symbol *symbol, struct gdbarch *gdbarch, | |
793 | struct agent_expr *ax, struct axs_value *value, | |
794 | gdb_byte *data, int size) | |
795 | { | |
796 | gdb_byte *end = data + size; | |
797 | enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); | |
798 | /* In practice, a variable is not going to be spread across | |
799 | dozens of registers or memory locations. If someone comes up | |
800 | with a real-world example, revisit this. */ | |
801 | #define MAX_FRAGS 16 | |
802 | struct axs_var_loc fragments[MAX_FRAGS]; | |
803 | int nfrags = 0, frag; | |
804 | int length = 0; | |
805 | int piece_ok = 0; | |
806 | int bad = 0; | |
807 | int first = 1; | |
808 | ||
809 | if (!data || size == 0) | |
810 | { | |
811 | value->optimized_out = 1; | |
812 | return; | |
813 | } | |
814 | ||
815 | while (data < end) | |
816 | { | |
817 | if (!piece_ok) | |
818 | { | |
819 | if (nfrags == MAX_FRAGS) | |
820 | error (_("Too many pieces in location for \"%s\"."), | |
821 | SYMBOL_PRINT_NAME (symbol)); | |
822 | ||
823 | fragments[nfrags].bytes = 0; | |
824 | data = dwarf2_tracepoint_var_loc (symbol, ax, &fragments[nfrags], | |
825 | gdbarch, data, end); | |
826 | nfrags++; | |
827 | piece_ok = 1; | |
828 | } | |
829 | else if (data[0] == DW_OP_piece) | |
830 | { | |
831 | ULONGEST bytes; | |
832 | ||
833 | data = read_uleb128 (data + 1, end, &bytes); | |
834 | /* Only deal with 4 byte fragments for now. */ | |
835 | if (bytes != 4) | |
836 | error (_("DW_OP_piece %s not supported in location for \"%s\"."), | |
837 | pulongest (bytes), SYMBOL_PRINT_NAME (symbol)); | |
838 | fragments[nfrags - 1].bytes = bytes; | |
839 | length += bytes; | |
840 | piece_ok = 0; | |
841 | } | |
842 | else | |
843 | { | |
844 | bad = 1; | |
845 | break; | |
846 | } | |
847 | } | |
848 | ||
849 | if (bad || data > end) | |
850 | error (_("Corrupted DWARF expression for \"%s\"."), | |
851 | SYMBOL_PRINT_NAME (symbol)); | |
852 | ||
853 | /* If single expression, no pieces, convert to external format. */ | |
854 | if (length == 0) | |
855 | { | |
856 | dwarf2_tracepoint_var_access (ax, value, &fragments[0]); | |
857 | return; | |
858 | } | |
859 | ||
860 | if (length != TYPE_LENGTH (value->type)) | |
861 | error (_("Inconsistent piece information for \"%s\"."), | |
862 | SYMBOL_PRINT_NAME (symbol)); | |
863 | ||
864 | /* Emit bytecodes to assemble the pieces into a single stack entry. */ | |
865 | ||
866 | for ((frag = (byte_order == BFD_ENDIAN_BIG ? 0 : nfrags - 1)); | |
867 | nfrags--; | |
868 | (frag += (byte_order == BFD_ENDIAN_BIG ? 1 : -1))) | |
869 | { | |
870 | if (!first) | |
871 | { | |
872 | /* shift the previous fragment up 32 bits */ | |
873 | ax_const_l (ax, 32); | |
874 | ax_simple (ax, aop_lsh); | |
875 | } | |
876 | ||
877 | dwarf2_tracepoint_var_access (ax, value, &fragments[frag]); | |
878 | ||
879 | switch (value->kind) | |
880 | { | |
881 | case axs_lvalue_register: | |
882 | ax_reg (ax, value->u.reg); | |
883 | break; | |
884 | ||
885 | case axs_lvalue_memory: | |
886 | { | |
887 | extern int trace_kludge; /* Ugh. */ | |
888 | ||
889 | gdb_assert (fragments[frag].bytes == 4); | |
890 | if (trace_kludge) | |
891 | ax_trace_quick (ax, 4); | |
892 | ax_simple (ax, aop_ref32); | |
893 | } | |
894 | break; | |
895 | } | |
896 | ||
897 | if (!first) | |
898 | { | |
899 | /* or the new fragment into the previous */ | |
900 | ax_zero_ext (ax, 32); | |
901 | ax_simple (ax, aop_bit_or); | |
902 | } | |
903 | first = 0; | |
904 | } | |
905 | value->kind = axs_rvalue; | |
906 | } | |
907 | ||
4c2df51b DJ |
908 | \f |
909 | /* Return the value of SYMBOL in FRAME using the DWARF-2 expression | |
910 | evaluator to calculate the location. */ | |
911 | static struct value * | |
912 | locexpr_read_variable (struct symbol *symbol, struct frame_info *frame) | |
913 | { | |
914 | struct dwarf2_locexpr_baton *dlbaton = SYMBOL_LOCATION_BATON (symbol); | |
915 | struct value *val; | |
9a619af0 | 916 | |
a2d33775 JK |
917 | val = dwarf2_evaluate_loc_desc (SYMBOL_TYPE (symbol), frame, dlbaton->data, |
918 | dlbaton->size, dlbaton->per_cu); | |
4c2df51b DJ |
919 | |
920 | return val; | |
921 | } | |
922 | ||
923 | /* Return non-zero iff we need a frame to evaluate SYMBOL. */ | |
924 | static int | |
925 | locexpr_read_needs_frame (struct symbol *symbol) | |
926 | { | |
927 | struct dwarf2_locexpr_baton *dlbaton = SYMBOL_LOCATION_BATON (symbol); | |
9a619af0 | 928 | |
ae0d2f24 UW |
929 | return dwarf2_loc_desc_needs_frame (dlbaton->data, dlbaton->size, |
930 | dlbaton->per_cu); | |
4c2df51b DJ |
931 | } |
932 | ||
08922a10 SS |
933 | /* Describe a single piece of a location, returning an updated |
934 | position in the bytecode sequence. */ | |
935 | ||
936 | static gdb_byte * | |
937 | locexpr_describe_location_piece (struct symbol *symbol, struct ui_file *stream, | |
938 | CORE_ADDR addr, struct objfile *objfile, | |
939 | gdb_byte *data, int size, unsigned int addr_size) | |
4c2df51b | 940 | { |
08922a10 SS |
941 | struct gdbarch *gdbarch = get_objfile_arch (objfile); |
942 | int regno; | |
943 | ||
944 | if (data[0] >= DW_OP_reg0 && data[0] <= DW_OP_reg31) | |
945 | { | |
946 | regno = gdbarch_dwarf2_reg_to_regnum (gdbarch, data[0] - DW_OP_reg0); | |
947 | fprintf_filtered (stream, _("a variable in $%s"), | |
948 | gdbarch_register_name (gdbarch, regno)); | |
949 | data += 1; | |
950 | } | |
951 | else if (data[0] == DW_OP_regx) | |
952 | { | |
953 | ULONGEST reg; | |
4c2df51b | 954 | |
08922a10 SS |
955 | data = read_uleb128 (data + 1, data + size, ®); |
956 | regno = gdbarch_dwarf2_reg_to_regnum (gdbarch, reg); | |
957 | fprintf_filtered (stream, _("a variable in $%s"), | |
958 | gdbarch_register_name (gdbarch, regno)); | |
959 | } | |
960 | else if (data[0] == DW_OP_fbreg) | |
4c2df51b | 961 | { |
08922a10 SS |
962 | struct block *b; |
963 | struct symbol *framefunc; | |
964 | int frame_reg = 0; | |
965 | LONGEST frame_offset; | |
966 | gdb_byte *base_data; | |
967 | size_t base_size; | |
968 | LONGEST base_offset = 0; | |
969 | ||
970 | b = block_for_pc (addr); | |
971 | ||
972 | if (!b) | |
973 | error (_("No block found for address for symbol \"%s\"."), | |
974 | SYMBOL_PRINT_NAME (symbol)); | |
975 | ||
976 | framefunc = block_linkage_function (b); | |
977 | ||
978 | if (!framefunc) | |
979 | error (_("No function found for block for symbol \"%s\"."), | |
980 | SYMBOL_PRINT_NAME (symbol)); | |
981 | ||
982 | dwarf_expr_frame_base_1 (framefunc, addr, &base_data, &base_size); | |
983 | ||
984 | if (base_data[0] >= DW_OP_breg0 && base_data[0] <= DW_OP_breg31) | |
985 | { | |
986 | gdb_byte *buf_end; | |
987 | ||
988 | frame_reg = base_data[0] - DW_OP_breg0; | |
989 | buf_end = read_sleb128 (base_data + 1, | |
990 | base_data + base_size, &base_offset); | |
991 | if (buf_end != base_data + base_size) | |
992 | error (_("Unexpected opcode after DW_OP_breg%u for symbol \"%s\"."), | |
993 | frame_reg, SYMBOL_PRINT_NAME (symbol)); | |
994 | } | |
995 | else if (base_data[0] >= DW_OP_reg0 && base_data[0] <= DW_OP_reg31) | |
996 | { | |
997 | /* The frame base is just the register, with no offset. */ | |
998 | frame_reg = base_data[0] - DW_OP_reg0; | |
999 | base_offset = 0; | |
1000 | } | |
1001 | else | |
1002 | { | |
1003 | /* We don't know what to do with the frame base expression, | |
1004 | so we can't trace this variable; give up. */ | |
1005 | error (_("Cannot describe location of symbol \"%s\"; " | |
1006 | "DWARF 2 encoding not handled, " | |
1007 | "first opcode in base data is 0x%x."), | |
1008 | SYMBOL_PRINT_NAME (symbol), base_data[0]); | |
1009 | } | |
1010 | ||
1011 | regno = gdbarch_dwarf2_reg_to_regnum (gdbarch, frame_reg); | |
1012 | ||
1013 | data = read_sleb128 (data + 1, data + size, &frame_offset); | |
1014 | ||
1015 | fprintf_filtered (stream, _("a variable at frame base reg $%s offset %s+%s"), | |
1016 | gdbarch_register_name (gdbarch, regno), | |
1017 | plongest (base_offset), plongest (frame_offset)); | |
1018 | } | |
1019 | else if (data[0] >= DW_OP_breg0 && data[0] <= DW_OP_breg31) | |
1020 | { | |
1021 | LONGEST offset; | |
1022 | ||
1023 | regno = gdbarch_dwarf2_reg_to_regnum (gdbarch, data[0] - DW_OP_breg0); | |
1024 | ||
1025 | data = read_sleb128 (data + 1, data + size, &offset); | |
1026 | ||
4c2df51b | 1027 | fprintf_filtered (stream, |
08922a10 SS |
1028 | _("a variable at offset %s from base reg $%s"), |
1029 | plongest (offset), | |
5e2b427d | 1030 | gdbarch_register_name (gdbarch, regno)); |
4c2df51b DJ |
1031 | } |
1032 | ||
c3228f12 EZ |
1033 | /* The location expression for a TLS variable looks like this (on a |
1034 | 64-bit LE machine): | |
1035 | ||
1036 | DW_AT_location : 10 byte block: 3 4 0 0 0 0 0 0 0 e0 | |
1037 | (DW_OP_addr: 4; DW_OP_GNU_push_tls_address) | |
1038 | ||
1039 | 0x3 is the encoding for DW_OP_addr, which has an operand as long | |
1040 | as the size of an address on the target machine (here is 8 | |
1041 | bytes). 0xe0 is the encoding for DW_OP_GNU_push_tls_address. | |
1042 | The operand represents the offset at which the variable is within | |
1043 | the thread local storage. */ | |
1044 | ||
08922a10 SS |
1045 | else if (size > 1 |
1046 | && data[size - 1] == DW_OP_GNU_push_tls_address | |
1047 | && data[0] == DW_OP_addr) | |
1048 | { | |
1049 | CORE_ADDR offset = dwarf2_read_address (gdbarch, | |
1050 | data + 1, | |
1051 | data + size - 1, | |
1052 | addr_size); | |
9a619af0 | 1053 | |
08922a10 SS |
1054 | fprintf_filtered (stream, |
1055 | _("a thread-local variable at offset %s " | |
1056 | "in the thread-local storage for `%s'"), | |
1057 | paddress (gdbarch, offset), objfile->name); | |
1058 | ||
1059 | data += 1 + addr_size + 1; | |
1060 | } | |
1061 | else | |
1062 | fprintf_filtered (stream, | |
1063 | _("a variable with complex or multiple locations (DWARF2)")); | |
c3228f12 | 1064 | |
08922a10 | 1065 | return data; |
4c2df51b DJ |
1066 | } |
1067 | ||
08922a10 SS |
1068 | /* Describe a single location, which may in turn consist of multiple |
1069 | pieces. */ | |
a55cc764 | 1070 | |
08922a10 SS |
1071 | static void |
1072 | locexpr_describe_location_1 (struct symbol *symbol, CORE_ADDR addr, | |
1073 | struct ui_file *stream, gdb_byte *data, int size, | |
1074 | struct objfile *objfile, unsigned int addr_size) | |
1075 | { | |
1076 | gdb_byte *end = data + size; | |
1077 | int piece_done = 0, first_piece = 1, bad = 0; | |
1078 | ||
1079 | /* A multi-piece description consists of multiple sequences of bytes | |
1080 | each followed by DW_OP_piece + length of piece. */ | |
1081 | while (data < end) | |
1082 | { | |
1083 | if (!piece_done) | |
1084 | { | |
1085 | if (first_piece) | |
1086 | first_piece = 0; | |
1087 | else | |
1088 | fprintf_filtered (stream, _(", and ")); | |
1089 | ||
1090 | data = locexpr_describe_location_piece (symbol, stream, addr, objfile, | |
1091 | data, size, addr_size); | |
1092 | piece_done = 1; | |
1093 | } | |
1094 | else if (data[0] == DW_OP_piece) | |
1095 | { | |
1096 | ULONGEST bytes; | |
1097 | ||
1098 | data = read_uleb128 (data + 1, end, &bytes); | |
1099 | ||
1100 | fprintf_filtered (stream, _(" [%s-byte piece]"), pulongest (bytes)); | |
1101 | ||
1102 | piece_done = 0; | |
1103 | } | |
1104 | else | |
1105 | { | |
1106 | bad = 1; | |
1107 | break; | |
1108 | } | |
1109 | } | |
1110 | ||
1111 | if (bad || data > end) | |
1112 | error (_("Corrupted DWARF2 expression for \"%s\"."), | |
1113 | SYMBOL_PRINT_NAME (symbol)); | |
1114 | } | |
1115 | ||
1116 | /* Print a natural-language description of SYMBOL to STREAM. This | |
1117 | version is for a symbol with a single location. */ | |
a55cc764 | 1118 | |
08922a10 SS |
1119 | static void |
1120 | locexpr_describe_location (struct symbol *symbol, CORE_ADDR addr, | |
1121 | struct ui_file *stream) | |
1122 | { | |
1123 | struct dwarf2_locexpr_baton *dlbaton = SYMBOL_LOCATION_BATON (symbol); | |
1124 | struct objfile *objfile = dwarf2_per_cu_objfile (dlbaton->per_cu); | |
1125 | unsigned int addr_size = dwarf2_per_cu_addr_size (dlbaton->per_cu); | |
1126 | ||
1127 | locexpr_describe_location_1 (symbol, addr, stream, dlbaton->data, dlbaton->size, | |
1128 | objfile, addr_size); | |
1129 | } | |
1130 | ||
1131 | /* Describe the location of SYMBOL as an agent value in VALUE, generating | |
1132 | any necessary bytecode in AX. */ | |
a55cc764 | 1133 | |
0d53c4c4 | 1134 | static void |
505e835d UW |
1135 | locexpr_tracepoint_var_ref (struct symbol *symbol, struct gdbarch *gdbarch, |
1136 | struct agent_expr *ax, struct axs_value *value) | |
a55cc764 DJ |
1137 | { |
1138 | struct dwarf2_locexpr_baton *dlbaton = SYMBOL_LOCATION_BATON (symbol); | |
1139 | ||
505e835d UW |
1140 | dwarf2_tracepoint_var_ref (symbol, gdbarch, ax, value, |
1141 | dlbaton->data, dlbaton->size); | |
a55cc764 DJ |
1142 | } |
1143 | ||
4c2df51b DJ |
1144 | /* The set of location functions used with the DWARF-2 expression |
1145 | evaluator. */ | |
768a979c | 1146 | const struct symbol_computed_ops dwarf2_locexpr_funcs = { |
4c2df51b DJ |
1147 | locexpr_read_variable, |
1148 | locexpr_read_needs_frame, | |
1149 | locexpr_describe_location, | |
a55cc764 | 1150 | locexpr_tracepoint_var_ref |
4c2df51b | 1151 | }; |
0d53c4c4 DJ |
1152 | |
1153 | ||
1154 | /* Wrapper functions for location lists. These generally find | |
1155 | the appropriate location expression and call something above. */ | |
1156 | ||
1157 | /* Return the value of SYMBOL in FRAME using the DWARF-2 expression | |
1158 | evaluator to calculate the location. */ | |
1159 | static struct value * | |
1160 | loclist_read_variable (struct symbol *symbol, struct frame_info *frame) | |
1161 | { | |
1162 | struct dwarf2_loclist_baton *dlbaton = SYMBOL_LOCATION_BATON (symbol); | |
1163 | struct value *val; | |
852483bc | 1164 | gdb_byte *data; |
b6b08ebf | 1165 | size_t size; |
0d53c4c4 DJ |
1166 | |
1167 | data = find_location_expression (dlbaton, &size, | |
22c6caba JW |
1168 | frame ? get_frame_address_in_block (frame) |
1169 | : 0); | |
0d53c4c4 | 1170 | if (data == NULL) |
806048c6 DJ |
1171 | { |
1172 | val = allocate_value (SYMBOL_TYPE (symbol)); | |
1173 | VALUE_LVAL (val) = not_lval; | |
1174 | set_value_optimized_out (val, 1); | |
1175 | } | |
1176 | else | |
a2d33775 | 1177 | val = dwarf2_evaluate_loc_desc (SYMBOL_TYPE (symbol), frame, data, size, |
ae0d2f24 | 1178 | dlbaton->per_cu); |
0d53c4c4 DJ |
1179 | |
1180 | return val; | |
1181 | } | |
1182 | ||
1183 | /* Return non-zero iff we need a frame to evaluate SYMBOL. */ | |
1184 | static int | |
1185 | loclist_read_needs_frame (struct symbol *symbol) | |
1186 | { | |
1187 | /* If there's a location list, then assume we need to have a frame | |
1188 | to choose the appropriate location expression. With tracking of | |
1189 | global variables this is not necessarily true, but such tracking | |
1190 | is disabled in GCC at the moment until we figure out how to | |
1191 | represent it. */ | |
1192 | ||
1193 | return 1; | |
1194 | } | |
1195 | ||
08922a10 SS |
1196 | /* Print a natural-language description of SYMBOL to STREAM. This |
1197 | version applies when there is a list of different locations, each | |
1198 | with a specified address range. */ | |
1199 | ||
1200 | static void | |
1201 | loclist_describe_location (struct symbol *symbol, CORE_ADDR addr, | |
1202 | struct ui_file *stream) | |
0d53c4c4 | 1203 | { |
08922a10 SS |
1204 | struct dwarf2_loclist_baton *dlbaton = SYMBOL_LOCATION_BATON (symbol); |
1205 | CORE_ADDR low, high; | |
1206 | gdb_byte *loc_ptr, *buf_end; | |
1207 | int length, first = 1; | |
1208 | struct objfile *objfile = dwarf2_per_cu_objfile (dlbaton->per_cu); | |
1209 | struct gdbarch *gdbarch = get_objfile_arch (objfile); | |
1210 | enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); | |
1211 | unsigned int addr_size = dwarf2_per_cu_addr_size (dlbaton->per_cu); | |
1212 | CORE_ADDR base_mask = ~(~(CORE_ADDR)1 << (addr_size * 8 - 1)); | |
1213 | /* Adjust base_address for relocatable objects. */ | |
1214 | CORE_ADDR base_offset = ANOFFSET (objfile->section_offsets, | |
1215 | SECT_OFF_TEXT (objfile)); | |
1216 | CORE_ADDR base_address = dlbaton->base_address + base_offset; | |
1217 | ||
1218 | loc_ptr = dlbaton->data; | |
1219 | buf_end = dlbaton->data + dlbaton->size; | |
1220 | ||
1221 | fprintf_filtered (stream, _("multi-location (")); | |
1222 | ||
1223 | /* Iterate through locations until we run out. */ | |
1224 | while (1) | |
1225 | { | |
1226 | if (buf_end - loc_ptr < 2 * addr_size) | |
1227 | error (_("Corrupted DWARF expression for symbol \"%s\"."), | |
1228 | SYMBOL_PRINT_NAME (symbol)); | |
1229 | ||
1230 | low = extract_unsigned_integer (loc_ptr, addr_size, byte_order); | |
1231 | loc_ptr += addr_size; | |
1232 | ||
1233 | /* A base-address-selection entry. */ | |
1234 | if (low == base_mask) | |
1235 | { | |
1236 | base_address = dwarf2_read_address (gdbarch, | |
1237 | loc_ptr, buf_end, addr_size); | |
1238 | fprintf_filtered (stream, _("[base address %s]"), | |
1239 | paddress (gdbarch, base_address)); | |
1240 | loc_ptr += addr_size; | |
1241 | continue; | |
1242 | } | |
1243 | ||
1244 | high = extract_unsigned_integer (loc_ptr, addr_size, byte_order); | |
1245 | loc_ptr += addr_size; | |
1246 | ||
1247 | /* An end-of-list entry. */ | |
1248 | if (low == 0 && high == 0) | |
1249 | { | |
1250 | /* Indicate the end of the list, for readability. */ | |
1251 | fprintf_filtered (stream, _(")")); | |
1252 | return; | |
1253 | } | |
1254 | ||
1255 | /* Otherwise, a location expression entry. */ | |
1256 | low += base_address; | |
1257 | high += base_address; | |
1258 | ||
1259 | length = extract_unsigned_integer (loc_ptr, 2, byte_order); | |
1260 | loc_ptr += 2; | |
1261 | ||
1262 | /* Separate the different locations with a semicolon. */ | |
1263 | if (first) | |
1264 | first = 0; | |
1265 | else | |
1266 | fprintf_filtered (stream, _("; ")); | |
1267 | ||
1268 | /* (It would improve readability to print only the minimum | |
1269 | necessary digits of the second number of the range.) */ | |
1270 | fprintf_filtered (stream, _("range %s-%s, "), | |
1271 | paddress (gdbarch, low), paddress (gdbarch, high)); | |
1272 | ||
1273 | /* Now describe this particular location. */ | |
1274 | locexpr_describe_location_1 (symbol, low, stream, loc_ptr, length, | |
1275 | objfile, addr_size); | |
1276 | ||
1277 | loc_ptr += length; | |
1278 | } | |
0d53c4c4 DJ |
1279 | } |
1280 | ||
1281 | /* Describe the location of SYMBOL as an agent value in VALUE, generating | |
1282 | any necessary bytecode in AX. */ | |
1283 | static void | |
505e835d UW |
1284 | loclist_tracepoint_var_ref (struct symbol *symbol, struct gdbarch *gdbarch, |
1285 | struct agent_expr *ax, struct axs_value *value) | |
0d53c4c4 DJ |
1286 | { |
1287 | struct dwarf2_loclist_baton *dlbaton = SYMBOL_LOCATION_BATON (symbol); | |
852483bc | 1288 | gdb_byte *data; |
b6b08ebf | 1289 | size_t size; |
0d53c4c4 DJ |
1290 | |
1291 | data = find_location_expression (dlbaton, &size, ax->scope); | |
0d53c4c4 | 1292 | |
505e835d | 1293 | dwarf2_tracepoint_var_ref (symbol, gdbarch, ax, value, data, size); |
0d53c4c4 DJ |
1294 | } |
1295 | ||
1296 | /* The set of location functions used with the DWARF-2 expression | |
1297 | evaluator and location lists. */ | |
768a979c | 1298 | const struct symbol_computed_ops dwarf2_loclist_funcs = { |
0d53c4c4 DJ |
1299 | loclist_read_variable, |
1300 | loclist_read_needs_frame, | |
1301 | loclist_describe_location, | |
1302 | loclist_tracepoint_var_ref | |
1303 | }; |