Commit | Line | Data |
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4c2df51b | 1 | /* DWARF 2 location expression support for GDB. |
feb13ab0 | 2 | |
6aba47ca | 3 | Copyright (C) 2003, 2005, 2007 Free Software Foundation, Inc. |
feb13ab0 | 4 | |
4c2df51b DJ |
5 | Contributed by Daniel Jacobowitz, MontaVista Software, Inc. |
6 | ||
7 | This file is part of GDB. | |
8 | ||
9 | This program is free software; you can redistribute it and/or modify | |
10 | it under the terms of the GNU General Public License as published by | |
a9762ec7 JB |
11 | the Free Software Foundation; either version 3 of the License, or |
12 | (at your option) any later version. | |
4c2df51b | 13 | |
a9762ec7 JB |
14 | This program is distributed in the hope that it will be useful, |
15 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
16 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
17 | GNU General Public License for more details. | |
4c2df51b DJ |
18 | |
19 | You should have received a copy of the GNU General Public License | |
a9762ec7 | 20 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ |
4c2df51b DJ |
21 | |
22 | #include "defs.h" | |
23 | #include "ui-out.h" | |
24 | #include "value.h" | |
25 | #include "frame.h" | |
26 | #include "gdbcore.h" | |
27 | #include "target.h" | |
28 | #include "inferior.h" | |
a55cc764 DJ |
29 | #include "ax.h" |
30 | #include "ax-gdb.h" | |
e4adbba9 | 31 | #include "regcache.h" |
c3228f12 | 32 | #include "objfiles.h" |
93ad78a7 | 33 | #include "exceptions.h" |
4c2df51b DJ |
34 | |
35 | #include "elf/dwarf2.h" | |
36 | #include "dwarf2expr.h" | |
37 | #include "dwarf2loc.h" | |
38 | ||
39 | #include "gdb_string.h" | |
40 | ||
0d53c4c4 DJ |
41 | /* A helper function for dealing with location lists. Given a |
42 | symbol baton (BATON) and a pc value (PC), find the appropriate | |
43 | location expression, set *LOCEXPR_LENGTH, and return a pointer | |
44 | to the beginning of the expression. Returns NULL on failure. | |
45 | ||
46 | For now, only return the first matching location expression; there | |
47 | can be more than one in the list. */ | |
48 | ||
852483bc | 49 | static gdb_byte * |
0d53c4c4 | 50 | find_location_expression (struct dwarf2_loclist_baton *baton, |
b6b08ebf | 51 | size_t *locexpr_length, CORE_ADDR pc) |
0d53c4c4 | 52 | { |
0d53c4c4 | 53 | CORE_ADDR low, high; |
852483bc MK |
54 | gdb_byte *loc_ptr, *buf_end; |
55 | int length; | |
17a912b6 | 56 | unsigned int addr_size = gdbarch_addr_bit (current_gdbarch) / TARGET_CHAR_BIT; |
0d53c4c4 | 57 | CORE_ADDR base_mask = ~(~(CORE_ADDR)1 << (addr_size * 8 - 1)); |
8edfa926 BM |
58 | /* Adjust base_address for relocatable objects. */ |
59 | CORE_ADDR base_offset = ANOFFSET (baton->objfile->section_offsets, | |
60 | SECT_OFF_TEXT (baton->objfile)); | |
61 | CORE_ADDR base_address = baton->base_address + base_offset; | |
0d53c4c4 DJ |
62 | |
63 | loc_ptr = baton->data; | |
64 | buf_end = baton->data + baton->size; | |
65 | ||
66 | while (1) | |
67 | { | |
68 | low = dwarf2_read_address (loc_ptr, buf_end, &length); | |
69 | loc_ptr += length; | |
70 | high = dwarf2_read_address (loc_ptr, buf_end, &length); | |
71 | loc_ptr += length; | |
72 | ||
73 | /* An end-of-list entry. */ | |
74 | if (low == 0 && high == 0) | |
75 | return NULL; | |
76 | ||
77 | /* A base-address-selection entry. */ | |
78 | if ((low & base_mask) == base_mask) | |
79 | { | |
80 | base_address = high; | |
81 | continue; | |
82 | } | |
83 | ||
84 | /* Otherwise, a location expression entry. */ | |
85 | low += base_address; | |
86 | high += base_address; | |
87 | ||
88 | length = extract_unsigned_integer (loc_ptr, 2); | |
89 | loc_ptr += 2; | |
90 | ||
91 | if (pc >= low && pc < high) | |
92 | { | |
93 | *locexpr_length = length; | |
94 | return loc_ptr; | |
95 | } | |
96 | ||
97 | loc_ptr += length; | |
98 | } | |
99 | } | |
100 | ||
4c2df51b DJ |
101 | /* This is the baton used when performing dwarf2 expression |
102 | evaluation. */ | |
103 | struct dwarf_expr_baton | |
104 | { | |
105 | struct frame_info *frame; | |
106 | struct objfile *objfile; | |
107 | }; | |
108 | ||
109 | /* Helper functions for dwarf2_evaluate_loc_desc. */ | |
110 | ||
4bc9efe1 | 111 | /* Using the frame specified in BATON, return the value of register |
0b2b0195 | 112 | REGNUM, treated as a pointer. */ |
4c2df51b | 113 | static CORE_ADDR |
61fbb938 | 114 | dwarf_expr_read_reg (void *baton, int dwarf_regnum) |
4c2df51b | 115 | { |
4c2df51b | 116 | struct dwarf_expr_baton *debaton = (struct dwarf_expr_baton *) baton; |
e5192dd8 | 117 | CORE_ADDR result; |
0b2b0195 | 118 | int regnum; |
e4adbba9 | 119 | |
055d23b8 | 120 | regnum = gdbarch_dwarf2_reg_to_regnum (current_gdbarch, dwarf_regnum); |
0b2b0195 UW |
121 | result = address_from_register (builtin_type_void_data_ptr, |
122 | regnum, debaton->frame); | |
4c2df51b DJ |
123 | return result; |
124 | } | |
125 | ||
126 | /* Read memory at ADDR (length LEN) into BUF. */ | |
127 | ||
128 | static void | |
852483bc | 129 | dwarf_expr_read_mem (void *baton, gdb_byte *buf, CORE_ADDR addr, size_t len) |
4c2df51b DJ |
130 | { |
131 | read_memory (addr, buf, len); | |
132 | } | |
133 | ||
134 | /* Using the frame specified in BATON, find the location expression | |
135 | describing the frame base. Return a pointer to it in START and | |
136 | its length in LENGTH. */ | |
137 | static void | |
852483bc | 138 | dwarf_expr_frame_base (void *baton, gdb_byte **start, size_t * length) |
4c2df51b | 139 | { |
da62e633 AC |
140 | /* FIXME: cagney/2003-03-26: This code should be using |
141 | get_frame_base_address(), and then implement a dwarf2 specific | |
142 | this_base method. */ | |
4c2df51b | 143 | struct symbol *framefunc; |
4c2df51b | 144 | struct dwarf_expr_baton *debaton = (struct dwarf_expr_baton *) baton; |
0d53c4c4 | 145 | |
4c2df51b | 146 | framefunc = get_frame_function (debaton->frame); |
0d53c4c4 | 147 | |
a67af2b9 | 148 | if (SYMBOL_OPS (framefunc) == &dwarf2_loclist_funcs) |
0d53c4c4 DJ |
149 | { |
150 | struct dwarf2_loclist_baton *symbaton; | |
22c6caba JW |
151 | struct frame_info *frame = debaton->frame; |
152 | ||
0d53c4c4 DJ |
153 | symbaton = SYMBOL_LOCATION_BATON (framefunc); |
154 | *start = find_location_expression (symbaton, length, | |
22c6caba | 155 | get_frame_address_in_block (frame)); |
0d53c4c4 DJ |
156 | } |
157 | else | |
158 | { | |
159 | struct dwarf2_locexpr_baton *symbaton; | |
160 | symbaton = SYMBOL_LOCATION_BATON (framefunc); | |
161 | *length = symbaton->size; | |
162 | *start = symbaton->data; | |
163 | } | |
164 | ||
165 | if (*start == NULL) | |
8a3fe4f8 | 166 | error (_("Could not find the frame base for \"%s\"."), |
0d53c4c4 | 167 | SYMBOL_NATURAL_NAME (framefunc)); |
4c2df51b DJ |
168 | } |
169 | ||
170 | /* Using the objfile specified in BATON, find the address for the | |
171 | current thread's thread-local storage with offset OFFSET. */ | |
172 | static CORE_ADDR | |
173 | dwarf_expr_tls_address (void *baton, CORE_ADDR offset) | |
174 | { | |
175 | struct dwarf_expr_baton *debaton = (struct dwarf_expr_baton *) baton; | |
4c2df51b | 176 | |
9e35dae4 | 177 | return target_translate_tls_address (debaton->objfile, offset); |
4c2df51b DJ |
178 | } |
179 | ||
180 | /* Evaluate a location description, starting at DATA and with length | |
181 | SIZE, to find the current location of variable VAR in the context | |
182 | of FRAME. */ | |
183 | static struct value * | |
184 | dwarf2_evaluate_loc_desc (struct symbol *var, struct frame_info *frame, | |
852483bc | 185 | gdb_byte *data, unsigned short size, |
4c2df51b DJ |
186 | struct objfile *objfile) |
187 | { | |
87808bd6 | 188 | struct gdbarch *arch = get_frame_arch (frame); |
4c2df51b DJ |
189 | struct value *retval; |
190 | struct dwarf_expr_baton baton; | |
191 | struct dwarf_expr_context *ctx; | |
192 | ||
0d53c4c4 DJ |
193 | if (size == 0) |
194 | { | |
195 | retval = allocate_value (SYMBOL_TYPE (var)); | |
196 | VALUE_LVAL (retval) = not_lval; | |
feb13ab0 | 197 | set_value_optimized_out (retval, 1); |
10fb19b6 | 198 | return retval; |
0d53c4c4 DJ |
199 | } |
200 | ||
4c2df51b DJ |
201 | baton.frame = frame; |
202 | baton.objfile = objfile; | |
203 | ||
204 | ctx = new_dwarf_expr_context (); | |
205 | ctx->baton = &baton; | |
206 | ctx->read_reg = dwarf_expr_read_reg; | |
207 | ctx->read_mem = dwarf_expr_read_mem; | |
208 | ctx->get_frame_base = dwarf_expr_frame_base; | |
209 | ctx->get_tls_address = dwarf_expr_tls_address; | |
210 | ||
211 | dwarf_expr_eval (ctx, data, size); | |
87808bd6 JB |
212 | if (ctx->num_pieces > 0) |
213 | { | |
23572eca EZ |
214 | int i; |
215 | long offset = 0; | |
216 | bfd_byte *contents; | |
217 | ||
218 | retval = allocate_value (SYMBOL_TYPE (var)); | |
219 | contents = value_contents_raw (retval); | |
220 | for (i = 0; i < ctx->num_pieces; i++) | |
221 | { | |
222 | struct dwarf_expr_piece *p = &ctx->pieces[i]; | |
223 | if (p->in_reg) | |
224 | { | |
225 | bfd_byte regval[MAX_REGISTER_SIZE]; | |
055d23b8 UW |
226 | int gdb_regnum = gdbarch_dwarf2_reg_to_regnum |
227 | (current_gdbarch, p->value); | |
23572eca EZ |
228 | get_frame_register (frame, gdb_regnum, regval); |
229 | memcpy (contents + offset, regval, p->size); | |
230 | } | |
231 | else /* In memory? */ | |
232 | { | |
233 | read_memory (p->value, contents + offset, p->size); | |
234 | } | |
235 | offset += p->size; | |
236 | } | |
87808bd6 JB |
237 | } |
238 | else if (ctx->in_reg) | |
051caad9 | 239 | { |
5ca2e327 | 240 | CORE_ADDR dwarf_regnum = dwarf_expr_fetch (ctx, 0); |
055d23b8 UW |
241 | int gdb_regnum = gdbarch_dwarf2_reg_to_regnum |
242 | (current_gdbarch, dwarf_regnum); | |
5ca2e327 | 243 | retval = value_from_register (SYMBOL_TYPE (var), gdb_regnum, frame); |
051caad9 | 244 | } |
4c2df51b DJ |
245 | else |
246 | { | |
5ca2e327 JB |
247 | CORE_ADDR address = dwarf_expr_fetch (ctx, 0); |
248 | ||
61fbb938 | 249 | retval = allocate_value (SYMBOL_TYPE (var)); |
4c2df51b | 250 | VALUE_LVAL (retval) = lval_memory; |
dfa52d88 | 251 | set_value_lazy (retval, 1); |
5ca2e327 | 252 | VALUE_ADDRESS (retval) = address; |
4c2df51b DJ |
253 | } |
254 | ||
42be36b3 CT |
255 | set_value_initialized (retval, ctx->initialized); |
256 | ||
4c2df51b DJ |
257 | free_dwarf_expr_context (ctx); |
258 | ||
259 | return retval; | |
260 | } | |
261 | ||
262 | ||
263 | ||
264 | ||
265 | \f | |
266 | /* Helper functions and baton for dwarf2_loc_desc_needs_frame. */ | |
267 | ||
268 | struct needs_frame_baton | |
269 | { | |
270 | int needs_frame; | |
271 | }; | |
272 | ||
273 | /* Reads from registers do require a frame. */ | |
274 | static CORE_ADDR | |
61fbb938 | 275 | needs_frame_read_reg (void *baton, int regnum) |
4c2df51b DJ |
276 | { |
277 | struct needs_frame_baton *nf_baton = baton; | |
278 | nf_baton->needs_frame = 1; | |
279 | return 1; | |
280 | } | |
281 | ||
282 | /* Reads from memory do not require a frame. */ | |
283 | static void | |
852483bc | 284 | needs_frame_read_mem (void *baton, gdb_byte *buf, CORE_ADDR addr, size_t len) |
4c2df51b DJ |
285 | { |
286 | memset (buf, 0, len); | |
287 | } | |
288 | ||
289 | /* Frame-relative accesses do require a frame. */ | |
290 | static void | |
852483bc | 291 | needs_frame_frame_base (void *baton, gdb_byte **start, size_t * length) |
4c2df51b | 292 | { |
852483bc | 293 | static gdb_byte lit0 = DW_OP_lit0; |
4c2df51b DJ |
294 | struct needs_frame_baton *nf_baton = baton; |
295 | ||
296 | *start = &lit0; | |
297 | *length = 1; | |
298 | ||
299 | nf_baton->needs_frame = 1; | |
300 | } | |
301 | ||
302 | /* Thread-local accesses do require a frame. */ | |
303 | static CORE_ADDR | |
304 | needs_frame_tls_address (void *baton, CORE_ADDR offset) | |
305 | { | |
306 | struct needs_frame_baton *nf_baton = baton; | |
307 | nf_baton->needs_frame = 1; | |
308 | return 1; | |
309 | } | |
310 | ||
311 | /* Return non-zero iff the location expression at DATA (length SIZE) | |
312 | requires a frame to evaluate. */ | |
313 | ||
314 | static int | |
852483bc | 315 | dwarf2_loc_desc_needs_frame (gdb_byte *data, unsigned short size) |
4c2df51b DJ |
316 | { |
317 | struct needs_frame_baton baton; | |
318 | struct dwarf_expr_context *ctx; | |
f630a401 | 319 | int in_reg; |
4c2df51b DJ |
320 | |
321 | baton.needs_frame = 0; | |
322 | ||
323 | ctx = new_dwarf_expr_context (); | |
324 | ctx->baton = &baton; | |
325 | ctx->read_reg = needs_frame_read_reg; | |
326 | ctx->read_mem = needs_frame_read_mem; | |
327 | ctx->get_frame_base = needs_frame_frame_base; | |
328 | ctx->get_tls_address = needs_frame_tls_address; | |
329 | ||
330 | dwarf_expr_eval (ctx, data, size); | |
331 | ||
f630a401 DJ |
332 | in_reg = ctx->in_reg; |
333 | ||
87808bd6 JB |
334 | if (ctx->num_pieces > 0) |
335 | { | |
336 | int i; | |
337 | ||
338 | /* If the location has several pieces, and any of them are in | |
339 | registers, then we will need a frame to fetch them from. */ | |
340 | for (i = 0; i < ctx->num_pieces; i++) | |
341 | if (ctx->pieces[i].in_reg) | |
342 | in_reg = 1; | |
343 | } | |
344 | ||
4c2df51b DJ |
345 | free_dwarf_expr_context (ctx); |
346 | ||
f630a401 | 347 | return baton.needs_frame || in_reg; |
4c2df51b DJ |
348 | } |
349 | ||
0d53c4c4 | 350 | static void |
852483bc MK |
351 | dwarf2_tracepoint_var_ref (struct symbol *symbol, struct agent_expr *ax, |
352 | struct axs_value *value, gdb_byte *data, | |
0d53c4c4 DJ |
353 | int size) |
354 | { | |
355 | if (size == 0) | |
8a3fe4f8 | 356 | error (_("Symbol \"%s\" has been optimized out."), |
0d53c4c4 DJ |
357 | SYMBOL_PRINT_NAME (symbol)); |
358 | ||
359 | if (size == 1 | |
360 | && data[0] >= DW_OP_reg0 | |
361 | && data[0] <= DW_OP_reg31) | |
362 | { | |
363 | value->kind = axs_lvalue_register; | |
364 | value->u.reg = data[0] - DW_OP_reg0; | |
365 | } | |
366 | else if (data[0] == DW_OP_regx) | |
367 | { | |
368 | ULONGEST reg; | |
369 | read_uleb128 (data + 1, data + size, ®); | |
370 | value->kind = axs_lvalue_register; | |
371 | value->u.reg = reg; | |
372 | } | |
373 | else if (data[0] == DW_OP_fbreg) | |
374 | { | |
375 | /* And this is worse than just minimal; we should honor the frame base | |
376 | as above. */ | |
377 | int frame_reg; | |
378 | LONGEST frame_offset; | |
852483bc | 379 | gdb_byte *buf_end; |
0d53c4c4 DJ |
380 | |
381 | buf_end = read_sleb128 (data + 1, data + size, &frame_offset); | |
382 | if (buf_end != data + size) | |
8a3fe4f8 | 383 | error (_("Unexpected opcode after DW_OP_fbreg for symbol \"%s\"."), |
0d53c4c4 | 384 | SYMBOL_PRINT_NAME (symbol)); |
4c2df51b | 385 | |
c7bb205c UW |
386 | gdbarch_virtual_frame_pointer (current_gdbarch, |
387 | ax->scope, &frame_reg, &frame_offset); | |
0d53c4c4 DJ |
388 | ax_reg (ax, frame_reg); |
389 | ax_const_l (ax, frame_offset); | |
390 | ax_simple (ax, aop_add); | |
4c2df51b | 391 | |
9c238357 RC |
392 | value->kind = axs_lvalue_memory; |
393 | } | |
394 | else if (data[0] >= DW_OP_breg0 | |
395 | && data[0] <= DW_OP_breg31) | |
396 | { | |
397 | unsigned int reg; | |
398 | LONGEST offset; | |
399 | gdb_byte *buf_end; | |
400 | ||
401 | reg = data[0] - DW_OP_breg0; | |
402 | buf_end = read_sleb128 (data + 1, data + size, &offset); | |
403 | if (buf_end != data + size) | |
404 | error (_("Unexpected opcode after DW_OP_breg%u for symbol \"%s\"."), | |
405 | reg, SYMBOL_PRINT_NAME (symbol)); | |
406 | ||
407 | ax_reg (ax, reg); | |
408 | ax_const_l (ax, offset); | |
0d53c4c4 | 409 | ax_simple (ax, aop_add); |
9c238357 | 410 | |
0d53c4c4 DJ |
411 | value->kind = axs_lvalue_memory; |
412 | } | |
413 | else | |
9c238357 RC |
414 | error (_("Unsupported DWARF opcode 0x%x in the location of \"%s\"."), |
415 | data[0], SYMBOL_PRINT_NAME (symbol)); | |
0d53c4c4 | 416 | } |
4c2df51b DJ |
417 | \f |
418 | /* Return the value of SYMBOL in FRAME using the DWARF-2 expression | |
419 | evaluator to calculate the location. */ | |
420 | static struct value * | |
421 | locexpr_read_variable (struct symbol *symbol, struct frame_info *frame) | |
422 | { | |
423 | struct dwarf2_locexpr_baton *dlbaton = SYMBOL_LOCATION_BATON (symbol); | |
424 | struct value *val; | |
425 | val = dwarf2_evaluate_loc_desc (symbol, frame, dlbaton->data, dlbaton->size, | |
426 | dlbaton->objfile); | |
427 | ||
428 | return val; | |
429 | } | |
430 | ||
431 | /* Return non-zero iff we need a frame to evaluate SYMBOL. */ | |
432 | static int | |
433 | locexpr_read_needs_frame (struct symbol *symbol) | |
434 | { | |
435 | struct dwarf2_locexpr_baton *dlbaton = SYMBOL_LOCATION_BATON (symbol); | |
436 | return dwarf2_loc_desc_needs_frame (dlbaton->data, dlbaton->size); | |
437 | } | |
438 | ||
439 | /* Print a natural-language description of SYMBOL to STREAM. */ | |
440 | static int | |
441 | locexpr_describe_location (struct symbol *symbol, struct ui_file *stream) | |
442 | { | |
443 | /* FIXME: be more extensive. */ | |
444 | struct dwarf2_locexpr_baton *dlbaton = SYMBOL_LOCATION_BATON (symbol); | |
445 | ||
446 | if (dlbaton->size == 1 | |
447 | && dlbaton->data[0] >= DW_OP_reg0 | |
448 | && dlbaton->data[0] <= DW_OP_reg31) | |
449 | { | |
055d23b8 UW |
450 | int regno = gdbarch_dwarf2_reg_to_regnum |
451 | (current_gdbarch, dlbaton->data[0] - DW_OP_reg0); | |
4c2df51b | 452 | fprintf_filtered (stream, |
c9f4d572 UW |
453 | "a variable in register %s", |
454 | gdbarch_register_name (current_gdbarch, regno)); | |
4c2df51b DJ |
455 | return 1; |
456 | } | |
457 | ||
c3228f12 EZ |
458 | /* The location expression for a TLS variable looks like this (on a |
459 | 64-bit LE machine): | |
460 | ||
461 | DW_AT_location : 10 byte block: 3 4 0 0 0 0 0 0 0 e0 | |
462 | (DW_OP_addr: 4; DW_OP_GNU_push_tls_address) | |
463 | ||
464 | 0x3 is the encoding for DW_OP_addr, which has an operand as long | |
465 | as the size of an address on the target machine (here is 8 | |
466 | bytes). 0xe0 is the encoding for DW_OP_GNU_push_tls_address. | |
467 | The operand represents the offset at which the variable is within | |
468 | the thread local storage. */ | |
469 | ||
470 | if (dlbaton->size > 1 | |
471 | && dlbaton->data[dlbaton->size - 1] == DW_OP_GNU_push_tls_address) | |
472 | if (dlbaton->data[0] == DW_OP_addr) | |
473 | { | |
474 | int bytes_read; | |
475 | CORE_ADDR offset = dwarf2_read_address (&dlbaton->data[1], | |
c193f044 | 476 | &dlbaton->data[dlbaton->size - 1], |
c3228f12 EZ |
477 | &bytes_read); |
478 | fprintf_filtered (stream, | |
32ffcbed | 479 | "a thread-local variable at offset %s in the " |
c3228f12 EZ |
480 | "thread-local storage for `%s'", |
481 | paddr_nz (offset), dlbaton->objfile->name); | |
482 | return 1; | |
483 | } | |
484 | ||
485 | ||
4c2df51b DJ |
486 | fprintf_filtered (stream, |
487 | "a variable with complex or multiple locations (DWARF2)"); | |
488 | return 1; | |
489 | } | |
490 | ||
a55cc764 DJ |
491 | |
492 | /* Describe the location of SYMBOL as an agent value in VALUE, generating | |
493 | any necessary bytecode in AX. | |
494 | ||
495 | NOTE drow/2003-02-26: This function is extremely minimal, because | |
496 | doing it correctly is extremely complicated and there is no | |
497 | publicly available stub with tracepoint support for me to test | |
498 | against. When there is one this function should be revisited. */ | |
499 | ||
0d53c4c4 | 500 | static void |
a55cc764 DJ |
501 | locexpr_tracepoint_var_ref (struct symbol * symbol, struct agent_expr * ax, |
502 | struct axs_value * value) | |
503 | { | |
504 | struct dwarf2_locexpr_baton *dlbaton = SYMBOL_LOCATION_BATON (symbol); | |
505 | ||
0d53c4c4 | 506 | dwarf2_tracepoint_var_ref (symbol, ax, value, dlbaton->data, dlbaton->size); |
a55cc764 DJ |
507 | } |
508 | ||
4c2df51b DJ |
509 | /* The set of location functions used with the DWARF-2 expression |
510 | evaluator. */ | |
a67af2b9 | 511 | const struct symbol_ops dwarf2_locexpr_funcs = { |
4c2df51b DJ |
512 | locexpr_read_variable, |
513 | locexpr_read_needs_frame, | |
514 | locexpr_describe_location, | |
a55cc764 | 515 | locexpr_tracepoint_var_ref |
4c2df51b | 516 | }; |
0d53c4c4 DJ |
517 | |
518 | ||
519 | /* Wrapper functions for location lists. These generally find | |
520 | the appropriate location expression and call something above. */ | |
521 | ||
522 | /* Return the value of SYMBOL in FRAME using the DWARF-2 expression | |
523 | evaluator to calculate the location. */ | |
524 | static struct value * | |
525 | loclist_read_variable (struct symbol *symbol, struct frame_info *frame) | |
526 | { | |
527 | struct dwarf2_loclist_baton *dlbaton = SYMBOL_LOCATION_BATON (symbol); | |
528 | struct value *val; | |
852483bc | 529 | gdb_byte *data; |
b6b08ebf | 530 | size_t size; |
0d53c4c4 DJ |
531 | |
532 | data = find_location_expression (dlbaton, &size, | |
22c6caba JW |
533 | frame ? get_frame_address_in_block (frame) |
534 | : 0); | |
0d53c4c4 | 535 | if (data == NULL) |
806048c6 DJ |
536 | { |
537 | val = allocate_value (SYMBOL_TYPE (symbol)); | |
538 | VALUE_LVAL (val) = not_lval; | |
539 | set_value_optimized_out (val, 1); | |
540 | } | |
541 | else | |
542 | val = dwarf2_evaluate_loc_desc (symbol, frame, data, size, | |
543 | dlbaton->objfile); | |
0d53c4c4 DJ |
544 | |
545 | return val; | |
546 | } | |
547 | ||
548 | /* Return non-zero iff we need a frame to evaluate SYMBOL. */ | |
549 | static int | |
550 | loclist_read_needs_frame (struct symbol *symbol) | |
551 | { | |
552 | /* If there's a location list, then assume we need to have a frame | |
553 | to choose the appropriate location expression. With tracking of | |
554 | global variables this is not necessarily true, but such tracking | |
555 | is disabled in GCC at the moment until we figure out how to | |
556 | represent it. */ | |
557 | ||
558 | return 1; | |
559 | } | |
560 | ||
561 | /* Print a natural-language description of SYMBOL to STREAM. */ | |
562 | static int | |
563 | loclist_describe_location (struct symbol *symbol, struct ui_file *stream) | |
564 | { | |
565 | /* FIXME: Could print the entire list of locations. */ | |
566 | fprintf_filtered (stream, "a variable with multiple locations"); | |
567 | return 1; | |
568 | } | |
569 | ||
570 | /* Describe the location of SYMBOL as an agent value in VALUE, generating | |
571 | any necessary bytecode in AX. */ | |
572 | static void | |
573 | loclist_tracepoint_var_ref (struct symbol * symbol, struct agent_expr * ax, | |
574 | struct axs_value * value) | |
575 | { | |
576 | struct dwarf2_loclist_baton *dlbaton = SYMBOL_LOCATION_BATON (symbol); | |
852483bc | 577 | gdb_byte *data; |
b6b08ebf | 578 | size_t size; |
0d53c4c4 DJ |
579 | |
580 | data = find_location_expression (dlbaton, &size, ax->scope); | |
581 | if (data == NULL) | |
8a3fe4f8 | 582 | error (_("Variable \"%s\" is not available."), SYMBOL_NATURAL_NAME (symbol)); |
0d53c4c4 DJ |
583 | |
584 | dwarf2_tracepoint_var_ref (symbol, ax, value, data, size); | |
585 | } | |
586 | ||
587 | /* The set of location functions used with the DWARF-2 expression | |
588 | evaluator and location lists. */ | |
a67af2b9 | 589 | const struct symbol_ops dwarf2_loclist_funcs = { |
0d53c4c4 DJ |
590 | loclist_read_variable, |
591 | loclist_read_needs_frame, | |
592 | loclist_describe_location, | |
593 | loclist_tracepoint_var_ref | |
594 | }; |