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 | |
11 | the Free Software Foundation; either version 2 of the License, or (at | |
12 | your option) any later version. | |
13 | ||
14 | This program is distributed in the hope that it will be useful, but | |
15 | WITHOUT ANY WARRANTY; without even the implied warranty of | |
16 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
17 | General Public License for more details. | |
18 | ||
19 | You should have received a copy of the GNU General Public License | |
20 | along with this program; if not, write to the Free Software | |
197e01b6 EZ |
21 | Foundation, Inc., 51 Franklin Street, Fifth Floor, |
22 | Boston, MA 02110-1301, USA. */ | |
4c2df51b DJ |
23 | |
24 | #include "defs.h" | |
25 | #include "ui-out.h" | |
26 | #include "value.h" | |
27 | #include "frame.h" | |
28 | #include "gdbcore.h" | |
29 | #include "target.h" | |
30 | #include "inferior.h" | |
a55cc764 DJ |
31 | #include "ax.h" |
32 | #include "ax-gdb.h" | |
e4adbba9 | 33 | #include "regcache.h" |
c3228f12 | 34 | #include "objfiles.h" |
93ad78a7 | 35 | #include "exceptions.h" |
4c2df51b DJ |
36 | |
37 | #include "elf/dwarf2.h" | |
38 | #include "dwarf2expr.h" | |
39 | #include "dwarf2loc.h" | |
40 | ||
41 | #include "gdb_string.h" | |
42 | ||
0d53c4c4 DJ |
43 | /* A helper function for dealing with location lists. Given a |
44 | symbol baton (BATON) and a pc value (PC), find the appropriate | |
45 | location expression, set *LOCEXPR_LENGTH, and return a pointer | |
46 | to the beginning of the expression. Returns NULL on failure. | |
47 | ||
48 | For now, only return the first matching location expression; there | |
49 | can be more than one in the list. */ | |
50 | ||
852483bc | 51 | static gdb_byte * |
0d53c4c4 | 52 | find_location_expression (struct dwarf2_loclist_baton *baton, |
b6b08ebf | 53 | size_t *locexpr_length, CORE_ADDR pc) |
0d53c4c4 | 54 | { |
0d53c4c4 | 55 | CORE_ADDR low, high; |
852483bc MK |
56 | gdb_byte *loc_ptr, *buf_end; |
57 | int length; | |
17a912b6 | 58 | unsigned int addr_size = gdbarch_addr_bit (current_gdbarch) / TARGET_CHAR_BIT; |
0d53c4c4 | 59 | CORE_ADDR base_mask = ~(~(CORE_ADDR)1 << (addr_size * 8 - 1)); |
8edfa926 BM |
60 | /* Adjust base_address for relocatable objects. */ |
61 | CORE_ADDR base_offset = ANOFFSET (baton->objfile->section_offsets, | |
62 | SECT_OFF_TEXT (baton->objfile)); | |
63 | CORE_ADDR base_address = baton->base_address + base_offset; | |
0d53c4c4 DJ |
64 | |
65 | loc_ptr = baton->data; | |
66 | buf_end = baton->data + baton->size; | |
67 | ||
68 | while (1) | |
69 | { | |
70 | low = dwarf2_read_address (loc_ptr, buf_end, &length); | |
71 | loc_ptr += length; | |
72 | high = dwarf2_read_address (loc_ptr, buf_end, &length); | |
73 | loc_ptr += length; | |
74 | ||
75 | /* An end-of-list entry. */ | |
76 | if (low == 0 && high == 0) | |
77 | return NULL; | |
78 | ||
79 | /* A base-address-selection entry. */ | |
80 | if ((low & base_mask) == base_mask) | |
81 | { | |
82 | base_address = high; | |
83 | continue; | |
84 | } | |
85 | ||
86 | /* Otherwise, a location expression entry. */ | |
87 | low += base_address; | |
88 | high += base_address; | |
89 | ||
90 | length = extract_unsigned_integer (loc_ptr, 2); | |
91 | loc_ptr += 2; | |
92 | ||
93 | if (pc >= low && pc < high) | |
94 | { | |
95 | *locexpr_length = length; | |
96 | return loc_ptr; | |
97 | } | |
98 | ||
99 | loc_ptr += length; | |
100 | } | |
101 | } | |
102 | ||
4c2df51b DJ |
103 | /* This is the baton used when performing dwarf2 expression |
104 | evaluation. */ | |
105 | struct dwarf_expr_baton | |
106 | { | |
107 | struct frame_info *frame; | |
108 | struct objfile *objfile; | |
109 | }; | |
110 | ||
111 | /* Helper functions for dwarf2_evaluate_loc_desc. */ | |
112 | ||
4bc9efe1 | 113 | /* Using the frame specified in BATON, return the value of register |
0b2b0195 | 114 | REGNUM, treated as a pointer. */ |
4c2df51b | 115 | static CORE_ADDR |
61fbb938 | 116 | dwarf_expr_read_reg (void *baton, int dwarf_regnum) |
4c2df51b | 117 | { |
4c2df51b | 118 | struct dwarf_expr_baton *debaton = (struct dwarf_expr_baton *) baton; |
e5192dd8 | 119 | CORE_ADDR result; |
0b2b0195 | 120 | int regnum; |
e4adbba9 | 121 | |
055d23b8 | 122 | regnum = gdbarch_dwarf2_reg_to_regnum (current_gdbarch, dwarf_regnum); |
0b2b0195 UW |
123 | result = address_from_register (builtin_type_void_data_ptr, |
124 | regnum, debaton->frame); | |
4c2df51b DJ |
125 | return result; |
126 | } | |
127 | ||
128 | /* Read memory at ADDR (length LEN) into BUF. */ | |
129 | ||
130 | static void | |
852483bc | 131 | dwarf_expr_read_mem (void *baton, gdb_byte *buf, CORE_ADDR addr, size_t len) |
4c2df51b DJ |
132 | { |
133 | read_memory (addr, buf, len); | |
134 | } | |
135 | ||
136 | /* Using the frame specified in BATON, find the location expression | |
137 | describing the frame base. Return a pointer to it in START and | |
138 | its length in LENGTH. */ | |
139 | static void | |
852483bc | 140 | dwarf_expr_frame_base (void *baton, gdb_byte **start, size_t * length) |
4c2df51b | 141 | { |
da62e633 AC |
142 | /* FIXME: cagney/2003-03-26: This code should be using |
143 | get_frame_base_address(), and then implement a dwarf2 specific | |
144 | this_base method. */ | |
4c2df51b | 145 | struct symbol *framefunc; |
4c2df51b | 146 | struct dwarf_expr_baton *debaton = (struct dwarf_expr_baton *) baton; |
0d53c4c4 | 147 | |
4c2df51b | 148 | framefunc = get_frame_function (debaton->frame); |
0d53c4c4 | 149 | |
a67af2b9 | 150 | if (SYMBOL_OPS (framefunc) == &dwarf2_loclist_funcs) |
0d53c4c4 DJ |
151 | { |
152 | struct dwarf2_loclist_baton *symbaton; | |
22c6caba JW |
153 | struct frame_info *frame = debaton->frame; |
154 | ||
0d53c4c4 DJ |
155 | symbaton = SYMBOL_LOCATION_BATON (framefunc); |
156 | *start = find_location_expression (symbaton, length, | |
22c6caba | 157 | get_frame_address_in_block (frame)); |
0d53c4c4 DJ |
158 | } |
159 | else | |
160 | { | |
161 | struct dwarf2_locexpr_baton *symbaton; | |
162 | symbaton = SYMBOL_LOCATION_BATON (framefunc); | |
163 | *length = symbaton->size; | |
164 | *start = symbaton->data; | |
165 | } | |
166 | ||
167 | if (*start == NULL) | |
8a3fe4f8 | 168 | error (_("Could not find the frame base for \"%s\"."), |
0d53c4c4 | 169 | SYMBOL_NATURAL_NAME (framefunc)); |
4c2df51b DJ |
170 | } |
171 | ||
172 | /* Using the objfile specified in BATON, find the address for the | |
173 | current thread's thread-local storage with offset OFFSET. */ | |
174 | static CORE_ADDR | |
175 | dwarf_expr_tls_address (void *baton, CORE_ADDR offset) | |
176 | { | |
177 | struct dwarf_expr_baton *debaton = (struct dwarf_expr_baton *) baton; | |
4c2df51b | 178 | |
9e35dae4 | 179 | return target_translate_tls_address (debaton->objfile, offset); |
4c2df51b DJ |
180 | } |
181 | ||
182 | /* Evaluate a location description, starting at DATA and with length | |
183 | SIZE, to find the current location of variable VAR in the context | |
184 | of FRAME. */ | |
185 | static struct value * | |
186 | dwarf2_evaluate_loc_desc (struct symbol *var, struct frame_info *frame, | |
852483bc | 187 | gdb_byte *data, unsigned short size, |
4c2df51b DJ |
188 | struct objfile *objfile) |
189 | { | |
87808bd6 | 190 | struct gdbarch *arch = get_frame_arch (frame); |
4c2df51b DJ |
191 | struct value *retval; |
192 | struct dwarf_expr_baton baton; | |
193 | struct dwarf_expr_context *ctx; | |
194 | ||
0d53c4c4 DJ |
195 | if (size == 0) |
196 | { | |
197 | retval = allocate_value (SYMBOL_TYPE (var)); | |
198 | VALUE_LVAL (retval) = not_lval; | |
feb13ab0 | 199 | set_value_optimized_out (retval, 1); |
10fb19b6 | 200 | return retval; |
0d53c4c4 DJ |
201 | } |
202 | ||
4c2df51b DJ |
203 | baton.frame = frame; |
204 | baton.objfile = objfile; | |
205 | ||
206 | ctx = new_dwarf_expr_context (); | |
207 | ctx->baton = &baton; | |
208 | ctx->read_reg = dwarf_expr_read_reg; | |
209 | ctx->read_mem = dwarf_expr_read_mem; | |
210 | ctx->get_frame_base = dwarf_expr_frame_base; | |
211 | ctx->get_tls_address = dwarf_expr_tls_address; | |
212 | ||
213 | dwarf_expr_eval (ctx, data, size); | |
87808bd6 JB |
214 | if (ctx->num_pieces > 0) |
215 | { | |
23572eca EZ |
216 | int i; |
217 | long offset = 0; | |
218 | bfd_byte *contents; | |
219 | ||
220 | retval = allocate_value (SYMBOL_TYPE (var)); | |
221 | contents = value_contents_raw (retval); | |
222 | for (i = 0; i < ctx->num_pieces; i++) | |
223 | { | |
224 | struct dwarf_expr_piece *p = &ctx->pieces[i]; | |
225 | if (p->in_reg) | |
226 | { | |
227 | bfd_byte regval[MAX_REGISTER_SIZE]; | |
055d23b8 UW |
228 | int gdb_regnum = gdbarch_dwarf2_reg_to_regnum |
229 | (current_gdbarch, p->value); | |
23572eca EZ |
230 | get_frame_register (frame, gdb_regnum, regval); |
231 | memcpy (contents + offset, regval, p->size); | |
232 | } | |
233 | else /* In memory? */ | |
234 | { | |
235 | read_memory (p->value, contents + offset, p->size); | |
236 | } | |
237 | offset += p->size; | |
238 | } | |
87808bd6 JB |
239 | } |
240 | else if (ctx->in_reg) | |
051caad9 | 241 | { |
5ca2e327 | 242 | CORE_ADDR dwarf_regnum = dwarf_expr_fetch (ctx, 0); |
055d23b8 UW |
243 | int gdb_regnum = gdbarch_dwarf2_reg_to_regnum |
244 | (current_gdbarch, dwarf_regnum); | |
5ca2e327 | 245 | retval = value_from_register (SYMBOL_TYPE (var), gdb_regnum, frame); |
051caad9 | 246 | } |
4c2df51b DJ |
247 | else |
248 | { | |
5ca2e327 JB |
249 | CORE_ADDR address = dwarf_expr_fetch (ctx, 0); |
250 | ||
61fbb938 | 251 | retval = allocate_value (SYMBOL_TYPE (var)); |
4c2df51b | 252 | VALUE_LVAL (retval) = lval_memory; |
dfa52d88 | 253 | set_value_lazy (retval, 1); |
5ca2e327 | 254 | VALUE_ADDRESS (retval) = address; |
4c2df51b DJ |
255 | } |
256 | ||
42be36b3 CT |
257 | set_value_initialized (retval, ctx->initialized); |
258 | ||
4c2df51b DJ |
259 | free_dwarf_expr_context (ctx); |
260 | ||
261 | return retval; | |
262 | } | |
263 | ||
264 | ||
265 | ||
266 | ||
267 | \f | |
268 | /* Helper functions and baton for dwarf2_loc_desc_needs_frame. */ | |
269 | ||
270 | struct needs_frame_baton | |
271 | { | |
272 | int needs_frame; | |
273 | }; | |
274 | ||
275 | /* Reads from registers do require a frame. */ | |
276 | static CORE_ADDR | |
61fbb938 | 277 | needs_frame_read_reg (void *baton, int regnum) |
4c2df51b DJ |
278 | { |
279 | struct needs_frame_baton *nf_baton = baton; | |
280 | nf_baton->needs_frame = 1; | |
281 | return 1; | |
282 | } | |
283 | ||
284 | /* Reads from memory do not require a frame. */ | |
285 | static void | |
852483bc | 286 | needs_frame_read_mem (void *baton, gdb_byte *buf, CORE_ADDR addr, size_t len) |
4c2df51b DJ |
287 | { |
288 | memset (buf, 0, len); | |
289 | } | |
290 | ||
291 | /* Frame-relative accesses do require a frame. */ | |
292 | static void | |
852483bc | 293 | needs_frame_frame_base (void *baton, gdb_byte **start, size_t * length) |
4c2df51b | 294 | { |
852483bc | 295 | static gdb_byte lit0 = DW_OP_lit0; |
4c2df51b DJ |
296 | struct needs_frame_baton *nf_baton = baton; |
297 | ||
298 | *start = &lit0; | |
299 | *length = 1; | |
300 | ||
301 | nf_baton->needs_frame = 1; | |
302 | } | |
303 | ||
304 | /* Thread-local accesses do require a frame. */ | |
305 | static CORE_ADDR | |
306 | needs_frame_tls_address (void *baton, CORE_ADDR offset) | |
307 | { | |
308 | struct needs_frame_baton *nf_baton = baton; | |
309 | nf_baton->needs_frame = 1; | |
310 | return 1; | |
311 | } | |
312 | ||
313 | /* Return non-zero iff the location expression at DATA (length SIZE) | |
314 | requires a frame to evaluate. */ | |
315 | ||
316 | static int | |
852483bc | 317 | dwarf2_loc_desc_needs_frame (gdb_byte *data, unsigned short size) |
4c2df51b DJ |
318 | { |
319 | struct needs_frame_baton baton; | |
320 | struct dwarf_expr_context *ctx; | |
f630a401 | 321 | int in_reg; |
4c2df51b DJ |
322 | |
323 | baton.needs_frame = 0; | |
324 | ||
325 | ctx = new_dwarf_expr_context (); | |
326 | ctx->baton = &baton; | |
327 | ctx->read_reg = needs_frame_read_reg; | |
328 | ctx->read_mem = needs_frame_read_mem; | |
329 | ctx->get_frame_base = needs_frame_frame_base; | |
330 | ctx->get_tls_address = needs_frame_tls_address; | |
331 | ||
332 | dwarf_expr_eval (ctx, data, size); | |
333 | ||
f630a401 DJ |
334 | in_reg = ctx->in_reg; |
335 | ||
87808bd6 JB |
336 | if (ctx->num_pieces > 0) |
337 | { | |
338 | int i; | |
339 | ||
340 | /* If the location has several pieces, and any of them are in | |
341 | registers, then we will need a frame to fetch them from. */ | |
342 | for (i = 0; i < ctx->num_pieces; i++) | |
343 | if (ctx->pieces[i].in_reg) | |
344 | in_reg = 1; | |
345 | } | |
346 | ||
4c2df51b DJ |
347 | free_dwarf_expr_context (ctx); |
348 | ||
f630a401 | 349 | return baton.needs_frame || in_reg; |
4c2df51b DJ |
350 | } |
351 | ||
0d53c4c4 | 352 | static void |
852483bc MK |
353 | dwarf2_tracepoint_var_ref (struct symbol *symbol, struct agent_expr *ax, |
354 | struct axs_value *value, gdb_byte *data, | |
0d53c4c4 DJ |
355 | int size) |
356 | { | |
357 | if (size == 0) | |
8a3fe4f8 | 358 | error (_("Symbol \"%s\" has been optimized out."), |
0d53c4c4 DJ |
359 | SYMBOL_PRINT_NAME (symbol)); |
360 | ||
361 | if (size == 1 | |
362 | && data[0] >= DW_OP_reg0 | |
363 | && data[0] <= DW_OP_reg31) | |
364 | { | |
365 | value->kind = axs_lvalue_register; | |
366 | value->u.reg = data[0] - DW_OP_reg0; | |
367 | } | |
368 | else if (data[0] == DW_OP_regx) | |
369 | { | |
370 | ULONGEST reg; | |
371 | read_uleb128 (data + 1, data + size, ®); | |
372 | value->kind = axs_lvalue_register; | |
373 | value->u.reg = reg; | |
374 | } | |
375 | else if (data[0] == DW_OP_fbreg) | |
376 | { | |
377 | /* And this is worse than just minimal; we should honor the frame base | |
378 | as above. */ | |
379 | int frame_reg; | |
380 | LONGEST frame_offset; | |
852483bc | 381 | gdb_byte *buf_end; |
0d53c4c4 DJ |
382 | |
383 | buf_end = read_sleb128 (data + 1, data + size, &frame_offset); | |
384 | if (buf_end != data + size) | |
8a3fe4f8 | 385 | error (_("Unexpected opcode after DW_OP_fbreg for symbol \"%s\"."), |
0d53c4c4 | 386 | SYMBOL_PRINT_NAME (symbol)); |
4c2df51b | 387 | |
c7bb205c UW |
388 | gdbarch_virtual_frame_pointer (current_gdbarch, |
389 | ax->scope, &frame_reg, &frame_offset); | |
0d53c4c4 DJ |
390 | ax_reg (ax, frame_reg); |
391 | ax_const_l (ax, frame_offset); | |
392 | ax_simple (ax, aop_add); | |
4c2df51b | 393 | |
9c238357 RC |
394 | value->kind = axs_lvalue_memory; |
395 | } | |
396 | else if (data[0] >= DW_OP_breg0 | |
397 | && data[0] <= DW_OP_breg31) | |
398 | { | |
399 | unsigned int reg; | |
400 | LONGEST offset; | |
401 | gdb_byte *buf_end; | |
402 | ||
403 | reg = data[0] - DW_OP_breg0; | |
404 | buf_end = read_sleb128 (data + 1, data + size, &offset); | |
405 | if (buf_end != data + size) | |
406 | error (_("Unexpected opcode after DW_OP_breg%u for symbol \"%s\"."), | |
407 | reg, SYMBOL_PRINT_NAME (symbol)); | |
408 | ||
409 | ax_reg (ax, reg); | |
410 | ax_const_l (ax, offset); | |
0d53c4c4 | 411 | ax_simple (ax, aop_add); |
9c238357 | 412 | |
0d53c4c4 DJ |
413 | value->kind = axs_lvalue_memory; |
414 | } | |
415 | else | |
9c238357 RC |
416 | error (_("Unsupported DWARF opcode 0x%x in the location of \"%s\"."), |
417 | data[0], SYMBOL_PRINT_NAME (symbol)); | |
0d53c4c4 | 418 | } |
4c2df51b DJ |
419 | \f |
420 | /* Return the value of SYMBOL in FRAME using the DWARF-2 expression | |
421 | evaluator to calculate the location. */ | |
422 | static struct value * | |
423 | locexpr_read_variable (struct symbol *symbol, struct frame_info *frame) | |
424 | { | |
425 | struct dwarf2_locexpr_baton *dlbaton = SYMBOL_LOCATION_BATON (symbol); | |
426 | struct value *val; | |
427 | val = dwarf2_evaluate_loc_desc (symbol, frame, dlbaton->data, dlbaton->size, | |
428 | dlbaton->objfile); | |
429 | ||
430 | return val; | |
431 | } | |
432 | ||
433 | /* Return non-zero iff we need a frame to evaluate SYMBOL. */ | |
434 | static int | |
435 | locexpr_read_needs_frame (struct symbol *symbol) | |
436 | { | |
437 | struct dwarf2_locexpr_baton *dlbaton = SYMBOL_LOCATION_BATON (symbol); | |
438 | return dwarf2_loc_desc_needs_frame (dlbaton->data, dlbaton->size); | |
439 | } | |
440 | ||
441 | /* Print a natural-language description of SYMBOL to STREAM. */ | |
442 | static int | |
443 | locexpr_describe_location (struct symbol *symbol, struct ui_file *stream) | |
444 | { | |
445 | /* FIXME: be more extensive. */ | |
446 | struct dwarf2_locexpr_baton *dlbaton = SYMBOL_LOCATION_BATON (symbol); | |
447 | ||
448 | if (dlbaton->size == 1 | |
449 | && dlbaton->data[0] >= DW_OP_reg0 | |
450 | && dlbaton->data[0] <= DW_OP_reg31) | |
451 | { | |
055d23b8 UW |
452 | int regno = gdbarch_dwarf2_reg_to_regnum |
453 | (current_gdbarch, dlbaton->data[0] - DW_OP_reg0); | |
4c2df51b | 454 | fprintf_filtered (stream, |
c9f4d572 UW |
455 | "a variable in register %s", |
456 | gdbarch_register_name (current_gdbarch, regno)); | |
4c2df51b DJ |
457 | return 1; |
458 | } | |
459 | ||
c3228f12 EZ |
460 | /* The location expression for a TLS variable looks like this (on a |
461 | 64-bit LE machine): | |
462 | ||
463 | DW_AT_location : 10 byte block: 3 4 0 0 0 0 0 0 0 e0 | |
464 | (DW_OP_addr: 4; DW_OP_GNU_push_tls_address) | |
465 | ||
466 | 0x3 is the encoding for DW_OP_addr, which has an operand as long | |
467 | as the size of an address on the target machine (here is 8 | |
468 | bytes). 0xe0 is the encoding for DW_OP_GNU_push_tls_address. | |
469 | The operand represents the offset at which the variable is within | |
470 | the thread local storage. */ | |
471 | ||
472 | if (dlbaton->size > 1 | |
473 | && dlbaton->data[dlbaton->size - 1] == DW_OP_GNU_push_tls_address) | |
474 | if (dlbaton->data[0] == DW_OP_addr) | |
475 | { | |
476 | int bytes_read; | |
477 | CORE_ADDR offset = dwarf2_read_address (&dlbaton->data[1], | |
c193f044 | 478 | &dlbaton->data[dlbaton->size - 1], |
c3228f12 EZ |
479 | &bytes_read); |
480 | fprintf_filtered (stream, | |
32ffcbed | 481 | "a thread-local variable at offset %s in the " |
c3228f12 EZ |
482 | "thread-local storage for `%s'", |
483 | paddr_nz (offset), dlbaton->objfile->name); | |
484 | return 1; | |
485 | } | |
486 | ||
487 | ||
4c2df51b DJ |
488 | fprintf_filtered (stream, |
489 | "a variable with complex or multiple locations (DWARF2)"); | |
490 | return 1; | |
491 | } | |
492 | ||
a55cc764 DJ |
493 | |
494 | /* Describe the location of SYMBOL as an agent value in VALUE, generating | |
495 | any necessary bytecode in AX. | |
496 | ||
497 | NOTE drow/2003-02-26: This function is extremely minimal, because | |
498 | doing it correctly is extremely complicated and there is no | |
499 | publicly available stub with tracepoint support for me to test | |
500 | against. When there is one this function should be revisited. */ | |
501 | ||
0d53c4c4 | 502 | static void |
a55cc764 DJ |
503 | locexpr_tracepoint_var_ref (struct symbol * symbol, struct agent_expr * ax, |
504 | struct axs_value * value) | |
505 | { | |
506 | struct dwarf2_locexpr_baton *dlbaton = SYMBOL_LOCATION_BATON (symbol); | |
507 | ||
0d53c4c4 | 508 | dwarf2_tracepoint_var_ref (symbol, ax, value, dlbaton->data, dlbaton->size); |
a55cc764 DJ |
509 | } |
510 | ||
4c2df51b DJ |
511 | /* The set of location functions used with the DWARF-2 expression |
512 | evaluator. */ | |
a67af2b9 | 513 | const struct symbol_ops dwarf2_locexpr_funcs = { |
4c2df51b DJ |
514 | locexpr_read_variable, |
515 | locexpr_read_needs_frame, | |
516 | locexpr_describe_location, | |
a55cc764 | 517 | locexpr_tracepoint_var_ref |
4c2df51b | 518 | }; |
0d53c4c4 DJ |
519 | |
520 | ||
521 | /* Wrapper functions for location lists. These generally find | |
522 | the appropriate location expression and call something above. */ | |
523 | ||
524 | /* Return the value of SYMBOL in FRAME using the DWARF-2 expression | |
525 | evaluator to calculate the location. */ | |
526 | static struct value * | |
527 | loclist_read_variable (struct symbol *symbol, struct frame_info *frame) | |
528 | { | |
529 | struct dwarf2_loclist_baton *dlbaton = SYMBOL_LOCATION_BATON (symbol); | |
530 | struct value *val; | |
852483bc | 531 | gdb_byte *data; |
b6b08ebf | 532 | size_t size; |
0d53c4c4 DJ |
533 | |
534 | data = find_location_expression (dlbaton, &size, | |
22c6caba JW |
535 | frame ? get_frame_address_in_block (frame) |
536 | : 0); | |
0d53c4c4 | 537 | if (data == NULL) |
806048c6 DJ |
538 | { |
539 | val = allocate_value (SYMBOL_TYPE (symbol)); | |
540 | VALUE_LVAL (val) = not_lval; | |
541 | set_value_optimized_out (val, 1); | |
542 | } | |
543 | else | |
544 | val = dwarf2_evaluate_loc_desc (symbol, frame, data, size, | |
545 | dlbaton->objfile); | |
0d53c4c4 DJ |
546 | |
547 | return val; | |
548 | } | |
549 | ||
550 | /* Return non-zero iff we need a frame to evaluate SYMBOL. */ | |
551 | static int | |
552 | loclist_read_needs_frame (struct symbol *symbol) | |
553 | { | |
554 | /* If there's a location list, then assume we need to have a frame | |
555 | to choose the appropriate location expression. With tracking of | |
556 | global variables this is not necessarily true, but such tracking | |
557 | is disabled in GCC at the moment until we figure out how to | |
558 | represent it. */ | |
559 | ||
560 | return 1; | |
561 | } | |
562 | ||
563 | /* Print a natural-language description of SYMBOL to STREAM. */ | |
564 | static int | |
565 | loclist_describe_location (struct symbol *symbol, struct ui_file *stream) | |
566 | { | |
567 | /* FIXME: Could print the entire list of locations. */ | |
568 | fprintf_filtered (stream, "a variable with multiple locations"); | |
569 | return 1; | |
570 | } | |
571 | ||
572 | /* Describe the location of SYMBOL as an agent value in VALUE, generating | |
573 | any necessary bytecode in AX. */ | |
574 | static void | |
575 | loclist_tracepoint_var_ref (struct symbol * symbol, struct agent_expr * ax, | |
576 | struct axs_value * value) | |
577 | { | |
578 | struct dwarf2_loclist_baton *dlbaton = SYMBOL_LOCATION_BATON (symbol); | |
852483bc | 579 | gdb_byte *data; |
b6b08ebf | 580 | size_t size; |
0d53c4c4 DJ |
581 | |
582 | data = find_location_expression (dlbaton, &size, ax->scope); | |
583 | if (data == NULL) | |
8a3fe4f8 | 584 | error (_("Variable \"%s\" is not available."), SYMBOL_NATURAL_NAME (symbol)); |
0d53c4c4 DJ |
585 | |
586 | dwarf2_tracepoint_var_ref (symbol, ax, value, data, size); | |
587 | } | |
588 | ||
589 | /* The set of location functions used with the DWARF-2 expression | |
590 | evaluator and location lists. */ | |
a67af2b9 | 591 | const struct symbol_ops dwarf2_loclist_funcs = { |
0d53c4c4 DJ |
592 | loclist_read_variable, |
593 | loclist_read_needs_frame, | |
594 | loclist_describe_location, | |
595 | loclist_tracepoint_var_ref | |
596 | }; |