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" | |
eff4f95e | 40 | #include "gdb_assert.h" |
4c2df51b | 41 | |
0d53c4c4 DJ |
42 | /* A helper function for dealing with location lists. Given a |
43 | symbol baton (BATON) and a pc value (PC), find the appropriate | |
44 | location expression, set *LOCEXPR_LENGTH, and return a pointer | |
45 | to the beginning of the expression. Returns NULL on failure. | |
46 | ||
47 | For now, only return the first matching location expression; there | |
48 | can be more than one in the list. */ | |
49 | ||
852483bc | 50 | static gdb_byte * |
0d53c4c4 | 51 | find_location_expression (struct dwarf2_loclist_baton *baton, |
b6b08ebf | 52 | size_t *locexpr_length, CORE_ADDR pc) |
0d53c4c4 | 53 | { |
0d53c4c4 | 54 | CORE_ADDR low, high; |
852483bc MK |
55 | gdb_byte *loc_ptr, *buf_end; |
56 | int length; | |
17a912b6 | 57 | unsigned int addr_size = gdbarch_addr_bit (current_gdbarch) / TARGET_CHAR_BIT; |
0d53c4c4 | 58 | CORE_ADDR base_mask = ~(~(CORE_ADDR)1 << (addr_size * 8 - 1)); |
8edfa926 BM |
59 | /* Adjust base_address for relocatable objects. */ |
60 | CORE_ADDR base_offset = ANOFFSET (baton->objfile->section_offsets, | |
61 | SECT_OFF_TEXT (baton->objfile)); | |
62 | CORE_ADDR base_address = baton->base_address + base_offset; | |
0d53c4c4 DJ |
63 | |
64 | loc_ptr = baton->data; | |
65 | buf_end = baton->data + baton->size; | |
66 | ||
67 | while (1) | |
68 | { | |
69 | low = dwarf2_read_address (loc_ptr, buf_end, &length); | |
70 | loc_ptr += length; | |
71 | high = dwarf2_read_address (loc_ptr, buf_end, &length); | |
72 | loc_ptr += length; | |
73 | ||
74 | /* An end-of-list entry. */ | |
75 | if (low == 0 && high == 0) | |
76 | return NULL; | |
77 | ||
78 | /* A base-address-selection entry. */ | |
79 | if ((low & base_mask) == base_mask) | |
80 | { | |
81 | base_address = high; | |
82 | continue; | |
83 | } | |
84 | ||
85 | /* Otherwise, a location expression entry. */ | |
86 | low += base_address; | |
87 | high += base_address; | |
88 | ||
89 | length = extract_unsigned_integer (loc_ptr, 2); | |
90 | loc_ptr += 2; | |
91 | ||
92 | if (pc >= low && pc < high) | |
93 | { | |
94 | *locexpr_length = length; | |
95 | return loc_ptr; | |
96 | } | |
97 | ||
98 | loc_ptr += length; | |
99 | } | |
100 | } | |
101 | ||
4c2df51b DJ |
102 | /* This is the baton used when performing dwarf2 expression |
103 | evaluation. */ | |
104 | struct dwarf_expr_baton | |
105 | { | |
106 | struct frame_info *frame; | |
107 | struct objfile *objfile; | |
108 | }; | |
109 | ||
110 | /* Helper functions for dwarf2_evaluate_loc_desc. */ | |
111 | ||
4bc9efe1 | 112 | /* Using the frame specified in BATON, return the value of register |
0b2b0195 | 113 | REGNUM, treated as a pointer. */ |
4c2df51b | 114 | static CORE_ADDR |
61fbb938 | 115 | dwarf_expr_read_reg (void *baton, int dwarf_regnum) |
4c2df51b | 116 | { |
4c2df51b | 117 | struct dwarf_expr_baton *debaton = (struct dwarf_expr_baton *) baton; |
e5192dd8 | 118 | CORE_ADDR result; |
0b2b0195 | 119 | int regnum; |
e4adbba9 | 120 | |
055d23b8 | 121 | regnum = gdbarch_dwarf2_reg_to_regnum (current_gdbarch, dwarf_regnum); |
0b2b0195 UW |
122 | result = address_from_register (builtin_type_void_data_ptr, |
123 | regnum, debaton->frame); | |
4c2df51b DJ |
124 | return result; |
125 | } | |
126 | ||
127 | /* Read memory at ADDR (length LEN) into BUF. */ | |
128 | ||
129 | static void | |
852483bc | 130 | dwarf_expr_read_mem (void *baton, gdb_byte *buf, CORE_ADDR addr, size_t len) |
4c2df51b DJ |
131 | { |
132 | read_memory (addr, buf, len); | |
133 | } | |
134 | ||
135 | /* Using the frame specified in BATON, find the location expression | |
136 | describing the frame base. Return a pointer to it in START and | |
137 | its length in LENGTH. */ | |
138 | static void | |
852483bc | 139 | dwarf_expr_frame_base (void *baton, gdb_byte **start, size_t * length) |
4c2df51b | 140 | { |
da62e633 AC |
141 | /* FIXME: cagney/2003-03-26: This code should be using |
142 | get_frame_base_address(), and then implement a dwarf2 specific | |
143 | this_base method. */ | |
4c2df51b | 144 | struct symbol *framefunc; |
4c2df51b | 145 | struct dwarf_expr_baton *debaton = (struct dwarf_expr_baton *) baton; |
0d53c4c4 | 146 | |
4c2df51b | 147 | framefunc = get_frame_function (debaton->frame); |
0d53c4c4 | 148 | |
eff4f95e JG |
149 | /* If we found a frame-relative symbol then it was certainly within |
150 | some function associated with a frame. If we can't find the frame, | |
151 | something has gone wrong. */ | |
152 | gdb_assert (framefunc != NULL); | |
153 | ||
a67af2b9 | 154 | if (SYMBOL_OPS (framefunc) == &dwarf2_loclist_funcs) |
0d53c4c4 DJ |
155 | { |
156 | struct dwarf2_loclist_baton *symbaton; | |
22c6caba JW |
157 | struct frame_info *frame = debaton->frame; |
158 | ||
0d53c4c4 DJ |
159 | symbaton = SYMBOL_LOCATION_BATON (framefunc); |
160 | *start = find_location_expression (symbaton, length, | |
22c6caba | 161 | get_frame_address_in_block (frame)); |
0d53c4c4 DJ |
162 | } |
163 | else | |
164 | { | |
165 | struct dwarf2_locexpr_baton *symbaton; | |
166 | symbaton = SYMBOL_LOCATION_BATON (framefunc); | |
167 | *length = symbaton->size; | |
168 | *start = symbaton->data; | |
169 | } | |
170 | ||
171 | if (*start == NULL) | |
8a3fe4f8 | 172 | error (_("Could not find the frame base for \"%s\"."), |
0d53c4c4 | 173 | SYMBOL_NATURAL_NAME (framefunc)); |
4c2df51b DJ |
174 | } |
175 | ||
176 | /* Using the objfile specified in BATON, find the address for the | |
177 | current thread's thread-local storage with offset OFFSET. */ | |
178 | static CORE_ADDR | |
179 | dwarf_expr_tls_address (void *baton, CORE_ADDR offset) | |
180 | { | |
181 | struct dwarf_expr_baton *debaton = (struct dwarf_expr_baton *) baton; | |
4c2df51b | 182 | |
9e35dae4 | 183 | return target_translate_tls_address (debaton->objfile, offset); |
4c2df51b DJ |
184 | } |
185 | ||
186 | /* Evaluate a location description, starting at DATA and with length | |
187 | SIZE, to find the current location of variable VAR in the context | |
188 | of FRAME. */ | |
189 | static struct value * | |
190 | dwarf2_evaluate_loc_desc (struct symbol *var, struct frame_info *frame, | |
852483bc | 191 | gdb_byte *data, unsigned short size, |
4c2df51b DJ |
192 | struct objfile *objfile) |
193 | { | |
87808bd6 | 194 | struct gdbarch *arch = get_frame_arch (frame); |
4c2df51b DJ |
195 | struct value *retval; |
196 | struct dwarf_expr_baton baton; | |
197 | struct dwarf_expr_context *ctx; | |
198 | ||
0d53c4c4 DJ |
199 | if (size == 0) |
200 | { | |
201 | retval = allocate_value (SYMBOL_TYPE (var)); | |
202 | VALUE_LVAL (retval) = not_lval; | |
feb13ab0 | 203 | set_value_optimized_out (retval, 1); |
10fb19b6 | 204 | return retval; |
0d53c4c4 DJ |
205 | } |
206 | ||
4c2df51b DJ |
207 | baton.frame = frame; |
208 | baton.objfile = objfile; | |
209 | ||
210 | ctx = new_dwarf_expr_context (); | |
211 | ctx->baton = &baton; | |
212 | ctx->read_reg = dwarf_expr_read_reg; | |
213 | ctx->read_mem = dwarf_expr_read_mem; | |
214 | ctx->get_frame_base = dwarf_expr_frame_base; | |
215 | ctx->get_tls_address = dwarf_expr_tls_address; | |
216 | ||
217 | dwarf_expr_eval (ctx, data, size); | |
87808bd6 JB |
218 | if (ctx->num_pieces > 0) |
219 | { | |
23572eca EZ |
220 | int i; |
221 | long offset = 0; | |
222 | bfd_byte *contents; | |
223 | ||
224 | retval = allocate_value (SYMBOL_TYPE (var)); | |
225 | contents = value_contents_raw (retval); | |
226 | for (i = 0; i < ctx->num_pieces; i++) | |
227 | { | |
228 | struct dwarf_expr_piece *p = &ctx->pieces[i]; | |
229 | if (p->in_reg) | |
230 | { | |
231 | bfd_byte regval[MAX_REGISTER_SIZE]; | |
055d23b8 | 232 | int gdb_regnum = gdbarch_dwarf2_reg_to_regnum |
ad010def | 233 | (arch, p->value); |
23572eca EZ |
234 | get_frame_register (frame, gdb_regnum, regval); |
235 | memcpy (contents + offset, regval, p->size); | |
236 | } | |
237 | else /* In memory? */ | |
238 | { | |
239 | read_memory (p->value, contents + offset, p->size); | |
240 | } | |
241 | offset += p->size; | |
242 | } | |
87808bd6 JB |
243 | } |
244 | else if (ctx->in_reg) | |
051caad9 | 245 | { |
5ca2e327 | 246 | CORE_ADDR dwarf_regnum = dwarf_expr_fetch (ctx, 0); |
055d23b8 | 247 | int gdb_regnum = gdbarch_dwarf2_reg_to_regnum |
ad010def | 248 | (arch, dwarf_regnum); |
5ca2e327 | 249 | retval = value_from_register (SYMBOL_TYPE (var), gdb_regnum, frame); |
051caad9 | 250 | } |
4c2df51b DJ |
251 | else |
252 | { | |
5ca2e327 JB |
253 | CORE_ADDR address = dwarf_expr_fetch (ctx, 0); |
254 | ||
61fbb938 | 255 | retval = allocate_value (SYMBOL_TYPE (var)); |
4c2df51b | 256 | VALUE_LVAL (retval) = lval_memory; |
dfa52d88 | 257 | set_value_lazy (retval, 1); |
5ca2e327 | 258 | VALUE_ADDRESS (retval) = address; |
4c2df51b DJ |
259 | } |
260 | ||
42be36b3 CT |
261 | set_value_initialized (retval, ctx->initialized); |
262 | ||
4c2df51b DJ |
263 | free_dwarf_expr_context (ctx); |
264 | ||
265 | return retval; | |
266 | } | |
267 | ||
268 | ||
269 | ||
270 | ||
271 | \f | |
272 | /* Helper functions and baton for dwarf2_loc_desc_needs_frame. */ | |
273 | ||
274 | struct needs_frame_baton | |
275 | { | |
276 | int needs_frame; | |
277 | }; | |
278 | ||
279 | /* Reads from registers do require a frame. */ | |
280 | static CORE_ADDR | |
61fbb938 | 281 | needs_frame_read_reg (void *baton, int regnum) |
4c2df51b DJ |
282 | { |
283 | struct needs_frame_baton *nf_baton = baton; | |
284 | nf_baton->needs_frame = 1; | |
285 | return 1; | |
286 | } | |
287 | ||
288 | /* Reads from memory do not require a frame. */ | |
289 | static void | |
852483bc | 290 | needs_frame_read_mem (void *baton, gdb_byte *buf, CORE_ADDR addr, size_t len) |
4c2df51b DJ |
291 | { |
292 | memset (buf, 0, len); | |
293 | } | |
294 | ||
295 | /* Frame-relative accesses do require a frame. */ | |
296 | static void | |
852483bc | 297 | needs_frame_frame_base (void *baton, gdb_byte **start, size_t * length) |
4c2df51b | 298 | { |
852483bc | 299 | static gdb_byte lit0 = DW_OP_lit0; |
4c2df51b DJ |
300 | struct needs_frame_baton *nf_baton = baton; |
301 | ||
302 | *start = &lit0; | |
303 | *length = 1; | |
304 | ||
305 | nf_baton->needs_frame = 1; | |
306 | } | |
307 | ||
308 | /* Thread-local accesses do require a frame. */ | |
309 | static CORE_ADDR | |
310 | needs_frame_tls_address (void *baton, CORE_ADDR offset) | |
311 | { | |
312 | struct needs_frame_baton *nf_baton = baton; | |
313 | nf_baton->needs_frame = 1; | |
314 | return 1; | |
315 | } | |
316 | ||
317 | /* Return non-zero iff the location expression at DATA (length SIZE) | |
318 | requires a frame to evaluate. */ | |
319 | ||
320 | static int | |
852483bc | 321 | dwarf2_loc_desc_needs_frame (gdb_byte *data, unsigned short size) |
4c2df51b DJ |
322 | { |
323 | struct needs_frame_baton baton; | |
324 | struct dwarf_expr_context *ctx; | |
f630a401 | 325 | int in_reg; |
4c2df51b DJ |
326 | |
327 | baton.needs_frame = 0; | |
328 | ||
329 | ctx = new_dwarf_expr_context (); | |
330 | ctx->baton = &baton; | |
331 | ctx->read_reg = needs_frame_read_reg; | |
332 | ctx->read_mem = needs_frame_read_mem; | |
333 | ctx->get_frame_base = needs_frame_frame_base; | |
334 | ctx->get_tls_address = needs_frame_tls_address; | |
335 | ||
336 | dwarf_expr_eval (ctx, data, size); | |
337 | ||
f630a401 DJ |
338 | in_reg = ctx->in_reg; |
339 | ||
87808bd6 JB |
340 | if (ctx->num_pieces > 0) |
341 | { | |
342 | int i; | |
343 | ||
344 | /* If the location has several pieces, and any of them are in | |
345 | registers, then we will need a frame to fetch them from. */ | |
346 | for (i = 0; i < ctx->num_pieces; i++) | |
347 | if (ctx->pieces[i].in_reg) | |
348 | in_reg = 1; | |
349 | } | |
350 | ||
4c2df51b DJ |
351 | free_dwarf_expr_context (ctx); |
352 | ||
f630a401 | 353 | return baton.needs_frame || in_reg; |
4c2df51b DJ |
354 | } |
355 | ||
0d53c4c4 | 356 | static void |
852483bc MK |
357 | dwarf2_tracepoint_var_ref (struct symbol *symbol, struct agent_expr *ax, |
358 | struct axs_value *value, gdb_byte *data, | |
0d53c4c4 DJ |
359 | int size) |
360 | { | |
361 | if (size == 0) | |
8a3fe4f8 | 362 | error (_("Symbol \"%s\" has been optimized out."), |
0d53c4c4 DJ |
363 | SYMBOL_PRINT_NAME (symbol)); |
364 | ||
365 | if (size == 1 | |
366 | && data[0] >= DW_OP_reg0 | |
367 | && data[0] <= DW_OP_reg31) | |
368 | { | |
369 | value->kind = axs_lvalue_register; | |
370 | value->u.reg = data[0] - DW_OP_reg0; | |
371 | } | |
372 | else if (data[0] == DW_OP_regx) | |
373 | { | |
374 | ULONGEST reg; | |
375 | read_uleb128 (data + 1, data + size, ®); | |
376 | value->kind = axs_lvalue_register; | |
377 | value->u.reg = reg; | |
378 | } | |
379 | else if (data[0] == DW_OP_fbreg) | |
380 | { | |
381 | /* And this is worse than just minimal; we should honor the frame base | |
382 | as above. */ | |
383 | int frame_reg; | |
384 | LONGEST frame_offset; | |
852483bc | 385 | gdb_byte *buf_end; |
0d53c4c4 DJ |
386 | |
387 | buf_end = read_sleb128 (data + 1, data + size, &frame_offset); | |
388 | if (buf_end != data + size) | |
8a3fe4f8 | 389 | error (_("Unexpected opcode after DW_OP_fbreg for symbol \"%s\"."), |
0d53c4c4 | 390 | SYMBOL_PRINT_NAME (symbol)); |
4c2df51b | 391 | |
c7bb205c UW |
392 | gdbarch_virtual_frame_pointer (current_gdbarch, |
393 | ax->scope, &frame_reg, &frame_offset); | |
0d53c4c4 DJ |
394 | ax_reg (ax, frame_reg); |
395 | ax_const_l (ax, frame_offset); | |
396 | ax_simple (ax, aop_add); | |
4c2df51b | 397 | |
9c238357 RC |
398 | value->kind = axs_lvalue_memory; |
399 | } | |
400 | else if (data[0] >= DW_OP_breg0 | |
401 | && data[0] <= DW_OP_breg31) | |
402 | { | |
403 | unsigned int reg; | |
404 | LONGEST offset; | |
405 | gdb_byte *buf_end; | |
406 | ||
407 | reg = data[0] - DW_OP_breg0; | |
408 | buf_end = read_sleb128 (data + 1, data + size, &offset); | |
409 | if (buf_end != data + size) | |
410 | error (_("Unexpected opcode after DW_OP_breg%u for symbol \"%s\"."), | |
411 | reg, SYMBOL_PRINT_NAME (symbol)); | |
412 | ||
413 | ax_reg (ax, reg); | |
414 | ax_const_l (ax, offset); | |
0d53c4c4 | 415 | ax_simple (ax, aop_add); |
9c238357 | 416 | |
0d53c4c4 DJ |
417 | value->kind = axs_lvalue_memory; |
418 | } | |
419 | else | |
9c238357 RC |
420 | error (_("Unsupported DWARF opcode 0x%x in the location of \"%s\"."), |
421 | data[0], SYMBOL_PRINT_NAME (symbol)); | |
0d53c4c4 | 422 | } |
4c2df51b DJ |
423 | \f |
424 | /* Return the value of SYMBOL in FRAME using the DWARF-2 expression | |
425 | evaluator to calculate the location. */ | |
426 | static struct value * | |
427 | locexpr_read_variable (struct symbol *symbol, struct frame_info *frame) | |
428 | { | |
429 | struct dwarf2_locexpr_baton *dlbaton = SYMBOL_LOCATION_BATON (symbol); | |
430 | struct value *val; | |
431 | val = dwarf2_evaluate_loc_desc (symbol, frame, dlbaton->data, dlbaton->size, | |
432 | dlbaton->objfile); | |
433 | ||
434 | return val; | |
435 | } | |
436 | ||
437 | /* Return non-zero iff we need a frame to evaluate SYMBOL. */ | |
438 | static int | |
439 | locexpr_read_needs_frame (struct symbol *symbol) | |
440 | { | |
441 | struct dwarf2_locexpr_baton *dlbaton = SYMBOL_LOCATION_BATON (symbol); | |
442 | return dwarf2_loc_desc_needs_frame (dlbaton->data, dlbaton->size); | |
443 | } | |
444 | ||
445 | /* Print a natural-language description of SYMBOL to STREAM. */ | |
446 | static int | |
447 | locexpr_describe_location (struct symbol *symbol, struct ui_file *stream) | |
448 | { | |
449 | /* FIXME: be more extensive. */ | |
450 | struct dwarf2_locexpr_baton *dlbaton = SYMBOL_LOCATION_BATON (symbol); | |
451 | ||
452 | if (dlbaton->size == 1 | |
453 | && dlbaton->data[0] >= DW_OP_reg0 | |
454 | && dlbaton->data[0] <= DW_OP_reg31) | |
455 | { | |
055d23b8 UW |
456 | int regno = gdbarch_dwarf2_reg_to_regnum |
457 | (current_gdbarch, dlbaton->data[0] - DW_OP_reg0); | |
4c2df51b | 458 | fprintf_filtered (stream, |
c9f4d572 UW |
459 | "a variable in register %s", |
460 | gdbarch_register_name (current_gdbarch, regno)); | |
4c2df51b DJ |
461 | return 1; |
462 | } | |
463 | ||
c3228f12 EZ |
464 | /* The location expression for a TLS variable looks like this (on a |
465 | 64-bit LE machine): | |
466 | ||
467 | DW_AT_location : 10 byte block: 3 4 0 0 0 0 0 0 0 e0 | |
468 | (DW_OP_addr: 4; DW_OP_GNU_push_tls_address) | |
469 | ||
470 | 0x3 is the encoding for DW_OP_addr, which has an operand as long | |
471 | as the size of an address on the target machine (here is 8 | |
472 | bytes). 0xe0 is the encoding for DW_OP_GNU_push_tls_address. | |
473 | The operand represents the offset at which the variable is within | |
474 | the thread local storage. */ | |
475 | ||
476 | if (dlbaton->size > 1 | |
477 | && dlbaton->data[dlbaton->size - 1] == DW_OP_GNU_push_tls_address) | |
478 | if (dlbaton->data[0] == DW_OP_addr) | |
479 | { | |
480 | int bytes_read; | |
481 | CORE_ADDR offset = dwarf2_read_address (&dlbaton->data[1], | |
c193f044 | 482 | &dlbaton->data[dlbaton->size - 1], |
c3228f12 EZ |
483 | &bytes_read); |
484 | fprintf_filtered (stream, | |
32ffcbed | 485 | "a thread-local variable at offset %s in the " |
c3228f12 EZ |
486 | "thread-local storage for `%s'", |
487 | paddr_nz (offset), dlbaton->objfile->name); | |
488 | return 1; | |
489 | } | |
490 | ||
491 | ||
4c2df51b DJ |
492 | fprintf_filtered (stream, |
493 | "a variable with complex or multiple locations (DWARF2)"); | |
494 | return 1; | |
495 | } | |
496 | ||
a55cc764 DJ |
497 | |
498 | /* Describe the location of SYMBOL as an agent value in VALUE, generating | |
499 | any necessary bytecode in AX. | |
500 | ||
501 | NOTE drow/2003-02-26: This function is extremely minimal, because | |
502 | doing it correctly is extremely complicated and there is no | |
503 | publicly available stub with tracepoint support for me to test | |
504 | against. When there is one this function should be revisited. */ | |
505 | ||
0d53c4c4 | 506 | static void |
a55cc764 DJ |
507 | locexpr_tracepoint_var_ref (struct symbol * symbol, struct agent_expr * ax, |
508 | struct axs_value * value) | |
509 | { | |
510 | struct dwarf2_locexpr_baton *dlbaton = SYMBOL_LOCATION_BATON (symbol); | |
511 | ||
0d53c4c4 | 512 | dwarf2_tracepoint_var_ref (symbol, ax, value, dlbaton->data, dlbaton->size); |
a55cc764 DJ |
513 | } |
514 | ||
4c2df51b DJ |
515 | /* The set of location functions used with the DWARF-2 expression |
516 | evaluator. */ | |
a67af2b9 | 517 | const struct symbol_ops dwarf2_locexpr_funcs = { |
4c2df51b DJ |
518 | locexpr_read_variable, |
519 | locexpr_read_needs_frame, | |
520 | locexpr_describe_location, | |
a55cc764 | 521 | locexpr_tracepoint_var_ref |
4c2df51b | 522 | }; |
0d53c4c4 DJ |
523 | |
524 | ||
525 | /* Wrapper functions for location lists. These generally find | |
526 | the appropriate location expression and call something above. */ | |
527 | ||
528 | /* Return the value of SYMBOL in FRAME using the DWARF-2 expression | |
529 | evaluator to calculate the location. */ | |
530 | static struct value * | |
531 | loclist_read_variable (struct symbol *symbol, struct frame_info *frame) | |
532 | { | |
533 | struct dwarf2_loclist_baton *dlbaton = SYMBOL_LOCATION_BATON (symbol); | |
534 | struct value *val; | |
852483bc | 535 | gdb_byte *data; |
b6b08ebf | 536 | size_t size; |
0d53c4c4 DJ |
537 | |
538 | data = find_location_expression (dlbaton, &size, | |
22c6caba JW |
539 | frame ? get_frame_address_in_block (frame) |
540 | : 0); | |
0d53c4c4 | 541 | if (data == NULL) |
806048c6 DJ |
542 | { |
543 | val = allocate_value (SYMBOL_TYPE (symbol)); | |
544 | VALUE_LVAL (val) = not_lval; | |
545 | set_value_optimized_out (val, 1); | |
546 | } | |
547 | else | |
548 | val = dwarf2_evaluate_loc_desc (symbol, frame, data, size, | |
549 | dlbaton->objfile); | |
0d53c4c4 DJ |
550 | |
551 | return val; | |
552 | } | |
553 | ||
554 | /* Return non-zero iff we need a frame to evaluate SYMBOL. */ | |
555 | static int | |
556 | loclist_read_needs_frame (struct symbol *symbol) | |
557 | { | |
558 | /* If there's a location list, then assume we need to have a frame | |
559 | to choose the appropriate location expression. With tracking of | |
560 | global variables this is not necessarily true, but such tracking | |
561 | is disabled in GCC at the moment until we figure out how to | |
562 | represent it. */ | |
563 | ||
564 | return 1; | |
565 | } | |
566 | ||
567 | /* Print a natural-language description of SYMBOL to STREAM. */ | |
568 | static int | |
569 | loclist_describe_location (struct symbol *symbol, struct ui_file *stream) | |
570 | { | |
571 | /* FIXME: Could print the entire list of locations. */ | |
572 | fprintf_filtered (stream, "a variable with multiple locations"); | |
573 | return 1; | |
574 | } | |
575 | ||
576 | /* Describe the location of SYMBOL as an agent value in VALUE, generating | |
577 | any necessary bytecode in AX. */ | |
578 | static void | |
579 | loclist_tracepoint_var_ref (struct symbol * symbol, struct agent_expr * ax, | |
580 | struct axs_value * value) | |
581 | { | |
582 | struct dwarf2_loclist_baton *dlbaton = SYMBOL_LOCATION_BATON (symbol); | |
852483bc | 583 | gdb_byte *data; |
b6b08ebf | 584 | size_t size; |
0d53c4c4 DJ |
585 | |
586 | data = find_location_expression (dlbaton, &size, ax->scope); | |
587 | if (data == NULL) | |
8a3fe4f8 | 588 | error (_("Variable \"%s\" is not available."), SYMBOL_NATURAL_NAME (symbol)); |
0d53c4c4 DJ |
589 | |
590 | dwarf2_tracepoint_var_ref (symbol, ax, value, data, size); | |
591 | } | |
592 | ||
593 | /* The set of location functions used with the DWARF-2 expression | |
594 | evaluator and location lists. */ | |
a67af2b9 | 595 | const struct symbol_ops dwarf2_loclist_funcs = { |
0d53c4c4 DJ |
596 | loclist_read_variable, |
597 | loclist_read_needs_frame, | |
598 | loclist_describe_location, | |
599 | loclist_tracepoint_var_ref | |
600 | }; |