Commit | Line | Data |
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4c2df51b | 1 | /* DWARF 2 location expression support for GDB. |
feb13ab0 | 2 | |
0fb0cc75 | 3 | Copyright (C) 2003, 2005, 2007, 2008, 2009 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" |
edb3359d | 34 | #include "block.h" |
4c2df51b DJ |
35 | |
36 | #include "elf/dwarf2.h" | |
37 | #include "dwarf2expr.h" | |
38 | #include "dwarf2loc.h" | |
39 | ||
40 | #include "gdb_string.h" | |
eff4f95e | 41 | #include "gdb_assert.h" |
4c2df51b | 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; | |
ae0d2f24 | 58 | struct objfile *objfile = dwarf2_per_cu_objfile (baton->per_cu); |
f7fd4728 | 59 | struct gdbarch *gdbarch = get_objfile_arch (objfile); |
e17a4113 | 60 | enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); |
ae0d2f24 | 61 | unsigned int addr_size = dwarf2_per_cu_addr_size (baton->per_cu); |
0d53c4c4 | 62 | CORE_ADDR base_mask = ~(~(CORE_ADDR)1 << (addr_size * 8 - 1)); |
8edfa926 | 63 | /* Adjust base_address for relocatable objects. */ |
ae0d2f24 UW |
64 | CORE_ADDR base_offset = ANOFFSET (objfile->section_offsets, |
65 | SECT_OFF_TEXT (objfile)); | |
8edfa926 | 66 | CORE_ADDR base_address = baton->base_address + base_offset; |
0d53c4c4 DJ |
67 | |
68 | loc_ptr = baton->data; | |
69 | buf_end = baton->data + baton->size; | |
70 | ||
71 | while (1) | |
72 | { | |
f7fd4728 | 73 | low = dwarf2_read_address (gdbarch, loc_ptr, buf_end, addr_size); |
ae0d2f24 | 74 | loc_ptr += addr_size; |
f7fd4728 | 75 | high = dwarf2_read_address (gdbarch, loc_ptr, buf_end, addr_size); |
ae0d2f24 | 76 | loc_ptr += addr_size; |
0d53c4c4 DJ |
77 | |
78 | /* An end-of-list entry. */ | |
79 | if (low == 0 && high == 0) | |
80 | return NULL; | |
81 | ||
82 | /* A base-address-selection entry. */ | |
83 | if ((low & base_mask) == base_mask) | |
84 | { | |
85 | base_address = high; | |
86 | continue; | |
87 | } | |
88 | ||
89 | /* Otherwise, a location expression entry. */ | |
90 | low += base_address; | |
91 | high += base_address; | |
92 | ||
e17a4113 | 93 | length = extract_unsigned_integer (loc_ptr, 2, byte_order); |
0d53c4c4 DJ |
94 | loc_ptr += 2; |
95 | ||
96 | if (pc >= low && pc < high) | |
97 | { | |
98 | *locexpr_length = length; | |
99 | return loc_ptr; | |
100 | } | |
101 | ||
102 | loc_ptr += length; | |
103 | } | |
104 | } | |
105 | ||
4c2df51b DJ |
106 | /* This is the baton used when performing dwarf2 expression |
107 | evaluation. */ | |
108 | struct dwarf_expr_baton | |
109 | { | |
110 | struct frame_info *frame; | |
111 | struct objfile *objfile; | |
112 | }; | |
113 | ||
114 | /* Helper functions for dwarf2_evaluate_loc_desc. */ | |
115 | ||
4bc9efe1 | 116 | /* Using the frame specified in BATON, return the value of register |
0b2b0195 | 117 | REGNUM, treated as a pointer. */ |
4c2df51b | 118 | static CORE_ADDR |
61fbb938 | 119 | dwarf_expr_read_reg (void *baton, int dwarf_regnum) |
4c2df51b | 120 | { |
4c2df51b | 121 | struct dwarf_expr_baton *debaton = (struct dwarf_expr_baton *) baton; |
5e2b427d | 122 | struct gdbarch *gdbarch = get_frame_arch (debaton->frame); |
e5192dd8 | 123 | CORE_ADDR result; |
0b2b0195 | 124 | int regnum; |
e4adbba9 | 125 | |
5e2b427d UW |
126 | regnum = gdbarch_dwarf2_reg_to_regnum (gdbarch, dwarf_regnum); |
127 | result = address_from_register (builtin_type (gdbarch)->builtin_data_ptr, | |
0b2b0195 | 128 | regnum, debaton->frame); |
4c2df51b DJ |
129 | return result; |
130 | } | |
131 | ||
132 | /* Read memory at ADDR (length LEN) into BUF. */ | |
133 | ||
134 | static void | |
852483bc | 135 | dwarf_expr_read_mem (void *baton, gdb_byte *buf, CORE_ADDR addr, size_t len) |
4c2df51b DJ |
136 | { |
137 | read_memory (addr, buf, len); | |
138 | } | |
139 | ||
140 | /* Using the frame specified in BATON, find the location expression | |
141 | describing the frame base. Return a pointer to it in START and | |
142 | its length in LENGTH. */ | |
143 | static void | |
852483bc | 144 | dwarf_expr_frame_base (void *baton, gdb_byte **start, size_t * length) |
4c2df51b | 145 | { |
da62e633 AC |
146 | /* FIXME: cagney/2003-03-26: This code should be using |
147 | get_frame_base_address(), and then implement a dwarf2 specific | |
148 | this_base method. */ | |
4c2df51b | 149 | struct symbol *framefunc; |
4c2df51b | 150 | struct dwarf_expr_baton *debaton = (struct dwarf_expr_baton *) baton; |
0d53c4c4 | 151 | |
edb3359d DJ |
152 | /* Use block_linkage_function, which returns a real (not inlined) |
153 | function, instead of get_frame_function, which may return an | |
154 | inlined function. */ | |
155 | framefunc = block_linkage_function (get_frame_block (debaton->frame, NULL)); | |
0d53c4c4 | 156 | |
eff4f95e JG |
157 | /* If we found a frame-relative symbol then it was certainly within |
158 | some function associated with a frame. If we can't find the frame, | |
159 | something has gone wrong. */ | |
160 | gdb_assert (framefunc != NULL); | |
161 | ||
edb3359d DJ |
162 | if (SYMBOL_LOCATION_BATON (framefunc) == NULL) |
163 | *start = NULL; | |
164 | else if (SYMBOL_COMPUTED_OPS (framefunc) == &dwarf2_loclist_funcs) | |
0d53c4c4 DJ |
165 | { |
166 | struct dwarf2_loclist_baton *symbaton; | |
22c6caba JW |
167 | struct frame_info *frame = debaton->frame; |
168 | ||
0d53c4c4 DJ |
169 | symbaton = SYMBOL_LOCATION_BATON (framefunc); |
170 | *start = find_location_expression (symbaton, length, | |
22c6caba | 171 | get_frame_address_in_block (frame)); |
0d53c4c4 DJ |
172 | } |
173 | else | |
174 | { | |
175 | struct dwarf2_locexpr_baton *symbaton; | |
176 | symbaton = SYMBOL_LOCATION_BATON (framefunc); | |
ebd3bcc1 JK |
177 | if (symbaton != NULL) |
178 | { | |
179 | *length = symbaton->size; | |
180 | *start = symbaton->data; | |
181 | } | |
182 | else | |
183 | *start = NULL; | |
0d53c4c4 DJ |
184 | } |
185 | ||
186 | if (*start == NULL) | |
8a3fe4f8 | 187 | error (_("Could not find the frame base for \"%s\"."), |
0d53c4c4 | 188 | SYMBOL_NATURAL_NAME (framefunc)); |
4c2df51b DJ |
189 | } |
190 | ||
191 | /* Using the objfile specified in BATON, find the address for the | |
192 | current thread's thread-local storage with offset OFFSET. */ | |
193 | static CORE_ADDR | |
194 | dwarf_expr_tls_address (void *baton, CORE_ADDR offset) | |
195 | { | |
196 | struct dwarf_expr_baton *debaton = (struct dwarf_expr_baton *) baton; | |
4c2df51b | 197 | |
9e35dae4 | 198 | return target_translate_tls_address (debaton->objfile, offset); |
4c2df51b DJ |
199 | } |
200 | ||
201 | /* Evaluate a location description, starting at DATA and with length | |
202 | SIZE, to find the current location of variable VAR in the context | |
203 | of FRAME. */ | |
204 | static struct value * | |
205 | dwarf2_evaluate_loc_desc (struct symbol *var, struct frame_info *frame, | |
852483bc | 206 | gdb_byte *data, unsigned short size, |
ae0d2f24 | 207 | struct dwarf2_per_cu_data *per_cu) |
4c2df51b | 208 | { |
4c2df51b DJ |
209 | struct value *retval; |
210 | struct dwarf_expr_baton baton; | |
211 | struct dwarf_expr_context *ctx; | |
212 | ||
0d53c4c4 DJ |
213 | if (size == 0) |
214 | { | |
215 | retval = allocate_value (SYMBOL_TYPE (var)); | |
216 | VALUE_LVAL (retval) = not_lval; | |
feb13ab0 | 217 | set_value_optimized_out (retval, 1); |
10fb19b6 | 218 | return retval; |
0d53c4c4 DJ |
219 | } |
220 | ||
4c2df51b | 221 | baton.frame = frame; |
ae0d2f24 | 222 | baton.objfile = dwarf2_per_cu_objfile (per_cu); |
4c2df51b DJ |
223 | |
224 | ctx = new_dwarf_expr_context (); | |
f7fd4728 | 225 | ctx->gdbarch = get_objfile_arch (baton.objfile); |
ae0d2f24 | 226 | ctx->addr_size = dwarf2_per_cu_addr_size (per_cu); |
4c2df51b DJ |
227 | ctx->baton = &baton; |
228 | ctx->read_reg = dwarf_expr_read_reg; | |
229 | ctx->read_mem = dwarf_expr_read_mem; | |
230 | ctx->get_frame_base = dwarf_expr_frame_base; | |
231 | ctx->get_tls_address = dwarf_expr_tls_address; | |
232 | ||
233 | dwarf_expr_eval (ctx, data, size); | |
87808bd6 JB |
234 | if (ctx->num_pieces > 0) |
235 | { | |
23572eca EZ |
236 | int i; |
237 | long offset = 0; | |
238 | bfd_byte *contents; | |
239 | ||
240 | retval = allocate_value (SYMBOL_TYPE (var)); | |
241 | contents = value_contents_raw (retval); | |
242 | for (i = 0; i < ctx->num_pieces; i++) | |
243 | { | |
244 | struct dwarf_expr_piece *p = &ctx->pieces[i]; | |
245 | if (p->in_reg) | |
246 | { | |
77a732d9 | 247 | struct gdbarch *arch = get_frame_arch (frame); |
23572eca | 248 | bfd_byte regval[MAX_REGISTER_SIZE]; |
77a732d9 | 249 | int gdb_regnum = gdbarch_dwarf2_reg_to_regnum (arch, p->value); |
23572eca EZ |
250 | get_frame_register (frame, gdb_regnum, regval); |
251 | memcpy (contents + offset, regval, p->size); | |
252 | } | |
253 | else /* In memory? */ | |
254 | { | |
255 | read_memory (p->value, contents + offset, p->size); | |
256 | } | |
257 | offset += p->size; | |
258 | } | |
87808bd6 JB |
259 | } |
260 | else if (ctx->in_reg) | |
051caad9 | 261 | { |
77a732d9 | 262 | struct gdbarch *arch = get_frame_arch (frame); |
5ca2e327 | 263 | CORE_ADDR dwarf_regnum = dwarf_expr_fetch (ctx, 0); |
77a732d9 | 264 | int gdb_regnum = gdbarch_dwarf2_reg_to_regnum (arch, dwarf_regnum); |
5ca2e327 | 265 | retval = value_from_register (SYMBOL_TYPE (var), gdb_regnum, frame); |
051caad9 | 266 | } |
4c2df51b DJ |
267 | else |
268 | { | |
5ca2e327 JB |
269 | CORE_ADDR address = dwarf_expr_fetch (ctx, 0); |
270 | ||
61fbb938 | 271 | retval = allocate_value (SYMBOL_TYPE (var)); |
4c2df51b | 272 | VALUE_LVAL (retval) = lval_memory; |
dfa52d88 | 273 | set_value_lazy (retval, 1); |
42ae5230 | 274 | set_value_address (retval, address); |
4c2df51b DJ |
275 | } |
276 | ||
42be36b3 CT |
277 | set_value_initialized (retval, ctx->initialized); |
278 | ||
4c2df51b DJ |
279 | free_dwarf_expr_context (ctx); |
280 | ||
281 | return retval; | |
282 | } | |
283 | ||
284 | ||
285 | ||
286 | ||
287 | \f | |
288 | /* Helper functions and baton for dwarf2_loc_desc_needs_frame. */ | |
289 | ||
290 | struct needs_frame_baton | |
291 | { | |
292 | int needs_frame; | |
293 | }; | |
294 | ||
295 | /* Reads from registers do require a frame. */ | |
296 | static CORE_ADDR | |
61fbb938 | 297 | needs_frame_read_reg (void *baton, int regnum) |
4c2df51b DJ |
298 | { |
299 | struct needs_frame_baton *nf_baton = baton; | |
300 | nf_baton->needs_frame = 1; | |
301 | return 1; | |
302 | } | |
303 | ||
304 | /* Reads from memory do not require a frame. */ | |
305 | static void | |
852483bc | 306 | needs_frame_read_mem (void *baton, gdb_byte *buf, CORE_ADDR addr, size_t len) |
4c2df51b DJ |
307 | { |
308 | memset (buf, 0, len); | |
309 | } | |
310 | ||
311 | /* Frame-relative accesses do require a frame. */ | |
312 | static void | |
852483bc | 313 | needs_frame_frame_base (void *baton, gdb_byte **start, size_t * length) |
4c2df51b | 314 | { |
852483bc | 315 | static gdb_byte lit0 = DW_OP_lit0; |
4c2df51b DJ |
316 | struct needs_frame_baton *nf_baton = baton; |
317 | ||
318 | *start = &lit0; | |
319 | *length = 1; | |
320 | ||
321 | nf_baton->needs_frame = 1; | |
322 | } | |
323 | ||
324 | /* Thread-local accesses do require a frame. */ | |
325 | static CORE_ADDR | |
326 | needs_frame_tls_address (void *baton, CORE_ADDR offset) | |
327 | { | |
328 | struct needs_frame_baton *nf_baton = baton; | |
329 | nf_baton->needs_frame = 1; | |
330 | return 1; | |
331 | } | |
332 | ||
333 | /* Return non-zero iff the location expression at DATA (length SIZE) | |
334 | requires a frame to evaluate. */ | |
335 | ||
336 | static int | |
ae0d2f24 UW |
337 | dwarf2_loc_desc_needs_frame (gdb_byte *data, unsigned short size, |
338 | struct dwarf2_per_cu_data *per_cu) | |
4c2df51b DJ |
339 | { |
340 | struct needs_frame_baton baton; | |
341 | struct dwarf_expr_context *ctx; | |
f630a401 | 342 | int in_reg; |
4c2df51b DJ |
343 | |
344 | baton.needs_frame = 0; | |
345 | ||
346 | ctx = new_dwarf_expr_context (); | |
f7fd4728 | 347 | ctx->gdbarch = get_objfile_arch (dwarf2_per_cu_objfile (per_cu)); |
ae0d2f24 | 348 | ctx->addr_size = dwarf2_per_cu_addr_size (per_cu); |
4c2df51b DJ |
349 | ctx->baton = &baton; |
350 | ctx->read_reg = needs_frame_read_reg; | |
351 | ctx->read_mem = needs_frame_read_mem; | |
352 | ctx->get_frame_base = needs_frame_frame_base; | |
353 | ctx->get_tls_address = needs_frame_tls_address; | |
354 | ||
355 | dwarf_expr_eval (ctx, data, size); | |
356 | ||
f630a401 DJ |
357 | in_reg = ctx->in_reg; |
358 | ||
87808bd6 JB |
359 | if (ctx->num_pieces > 0) |
360 | { | |
361 | int i; | |
362 | ||
363 | /* If the location has several pieces, and any of them are in | |
364 | registers, then we will need a frame to fetch them from. */ | |
365 | for (i = 0; i < ctx->num_pieces; i++) | |
366 | if (ctx->pieces[i].in_reg) | |
367 | in_reg = 1; | |
368 | } | |
369 | ||
4c2df51b DJ |
370 | free_dwarf_expr_context (ctx); |
371 | ||
f630a401 | 372 | return baton.needs_frame || in_reg; |
4c2df51b DJ |
373 | } |
374 | ||
0d53c4c4 | 375 | static void |
505e835d UW |
376 | dwarf2_tracepoint_var_ref (struct symbol *symbol, struct gdbarch *gdbarch, |
377 | struct agent_expr *ax, struct axs_value *value, | |
378 | gdb_byte *data, int size) | |
0d53c4c4 DJ |
379 | { |
380 | if (size == 0) | |
8a3fe4f8 | 381 | error (_("Symbol \"%s\" has been optimized out."), |
0d53c4c4 DJ |
382 | SYMBOL_PRINT_NAME (symbol)); |
383 | ||
384 | if (size == 1 | |
385 | && data[0] >= DW_OP_reg0 | |
386 | && data[0] <= DW_OP_reg31) | |
387 | { | |
388 | value->kind = axs_lvalue_register; | |
389 | value->u.reg = data[0] - DW_OP_reg0; | |
390 | } | |
391 | else if (data[0] == DW_OP_regx) | |
392 | { | |
393 | ULONGEST reg; | |
394 | read_uleb128 (data + 1, data + size, ®); | |
395 | value->kind = axs_lvalue_register; | |
396 | value->u.reg = reg; | |
397 | } | |
398 | else if (data[0] == DW_OP_fbreg) | |
399 | { | |
400 | /* And this is worse than just minimal; we should honor the frame base | |
401 | as above. */ | |
402 | int frame_reg; | |
403 | LONGEST frame_offset; | |
852483bc | 404 | gdb_byte *buf_end; |
0d53c4c4 DJ |
405 | |
406 | buf_end = read_sleb128 (data + 1, data + size, &frame_offset); | |
407 | if (buf_end != data + size) | |
8a3fe4f8 | 408 | error (_("Unexpected opcode after DW_OP_fbreg for symbol \"%s\"."), |
0d53c4c4 | 409 | SYMBOL_PRINT_NAME (symbol)); |
4c2df51b | 410 | |
505e835d | 411 | gdbarch_virtual_frame_pointer (gdbarch, |
c7bb205c | 412 | ax->scope, &frame_reg, &frame_offset); |
0d53c4c4 DJ |
413 | ax_reg (ax, frame_reg); |
414 | ax_const_l (ax, frame_offset); | |
415 | ax_simple (ax, aop_add); | |
4c2df51b | 416 | |
9c238357 RC |
417 | value->kind = axs_lvalue_memory; |
418 | } | |
419 | else if (data[0] >= DW_OP_breg0 | |
420 | && data[0] <= DW_OP_breg31) | |
421 | { | |
422 | unsigned int reg; | |
423 | LONGEST offset; | |
424 | gdb_byte *buf_end; | |
425 | ||
426 | reg = data[0] - DW_OP_breg0; | |
427 | buf_end = read_sleb128 (data + 1, data + size, &offset); | |
428 | if (buf_end != data + size) | |
429 | error (_("Unexpected opcode after DW_OP_breg%u for symbol \"%s\"."), | |
430 | reg, SYMBOL_PRINT_NAME (symbol)); | |
431 | ||
432 | ax_reg (ax, reg); | |
433 | ax_const_l (ax, offset); | |
0d53c4c4 | 434 | ax_simple (ax, aop_add); |
9c238357 | 435 | |
0d53c4c4 DJ |
436 | value->kind = axs_lvalue_memory; |
437 | } | |
438 | else | |
9c238357 RC |
439 | error (_("Unsupported DWARF opcode 0x%x in the location of \"%s\"."), |
440 | data[0], SYMBOL_PRINT_NAME (symbol)); | |
0d53c4c4 | 441 | } |
4c2df51b DJ |
442 | \f |
443 | /* Return the value of SYMBOL in FRAME using the DWARF-2 expression | |
444 | evaluator to calculate the location. */ | |
445 | static struct value * | |
446 | locexpr_read_variable (struct symbol *symbol, struct frame_info *frame) | |
447 | { | |
448 | struct dwarf2_locexpr_baton *dlbaton = SYMBOL_LOCATION_BATON (symbol); | |
449 | struct value *val; | |
450 | val = dwarf2_evaluate_loc_desc (symbol, frame, dlbaton->data, dlbaton->size, | |
ae0d2f24 | 451 | dlbaton->per_cu); |
4c2df51b DJ |
452 | |
453 | return val; | |
454 | } | |
455 | ||
456 | /* Return non-zero iff we need a frame to evaluate SYMBOL. */ | |
457 | static int | |
458 | locexpr_read_needs_frame (struct symbol *symbol) | |
459 | { | |
460 | struct dwarf2_locexpr_baton *dlbaton = SYMBOL_LOCATION_BATON (symbol); | |
ae0d2f24 UW |
461 | return dwarf2_loc_desc_needs_frame (dlbaton->data, dlbaton->size, |
462 | dlbaton->per_cu); | |
4c2df51b DJ |
463 | } |
464 | ||
465 | /* Print a natural-language description of SYMBOL to STREAM. */ | |
466 | static int | |
467 | locexpr_describe_location (struct symbol *symbol, struct ui_file *stream) | |
468 | { | |
469 | /* FIXME: be more extensive. */ | |
470 | struct dwarf2_locexpr_baton *dlbaton = SYMBOL_LOCATION_BATON (symbol); | |
ae0d2f24 | 471 | int addr_size = dwarf2_per_cu_addr_size (dlbaton->per_cu); |
4c2df51b DJ |
472 | |
473 | if (dlbaton->size == 1 | |
474 | && dlbaton->data[0] >= DW_OP_reg0 | |
475 | && dlbaton->data[0] <= DW_OP_reg31) | |
476 | { | |
5e2b427d UW |
477 | struct objfile *objfile = dwarf2_per_cu_objfile (dlbaton->per_cu); |
478 | struct gdbarch *gdbarch = get_objfile_arch (objfile); | |
479 | int regno = gdbarch_dwarf2_reg_to_regnum (gdbarch, | |
480 | dlbaton->data[0] - DW_OP_reg0); | |
4c2df51b | 481 | fprintf_filtered (stream, |
c9f4d572 | 482 | "a variable in register %s", |
5e2b427d | 483 | gdbarch_register_name (gdbarch, regno)); |
4c2df51b DJ |
484 | return 1; |
485 | } | |
486 | ||
c3228f12 EZ |
487 | /* The location expression for a TLS variable looks like this (on a |
488 | 64-bit LE machine): | |
489 | ||
490 | DW_AT_location : 10 byte block: 3 4 0 0 0 0 0 0 0 e0 | |
491 | (DW_OP_addr: 4; DW_OP_GNU_push_tls_address) | |
492 | ||
493 | 0x3 is the encoding for DW_OP_addr, which has an operand as long | |
494 | as the size of an address on the target machine (here is 8 | |
495 | bytes). 0xe0 is the encoding for DW_OP_GNU_push_tls_address. | |
496 | The operand represents the offset at which the variable is within | |
497 | the thread local storage. */ | |
498 | ||
499 | if (dlbaton->size > 1 | |
500 | && dlbaton->data[dlbaton->size - 1] == DW_OP_GNU_push_tls_address) | |
501 | if (dlbaton->data[0] == DW_OP_addr) | |
502 | { | |
ae0d2f24 | 503 | struct objfile *objfile = dwarf2_per_cu_objfile (dlbaton->per_cu); |
f7fd4728 UW |
504 | struct gdbarch *gdbarch = get_objfile_arch (objfile); |
505 | CORE_ADDR offset = dwarf2_read_address (gdbarch, | |
506 | &dlbaton->data[1], | |
c193f044 | 507 | &dlbaton->data[dlbaton->size - 1], |
ae0d2f24 | 508 | addr_size); |
c3228f12 | 509 | fprintf_filtered (stream, |
32ffcbed | 510 | "a thread-local variable at offset %s in the " |
c3228f12 | 511 | "thread-local storage for `%s'", |
5af949e3 | 512 | paddress (gdbarch, offset), objfile->name); |
c3228f12 EZ |
513 | return 1; |
514 | } | |
515 | ||
516 | ||
4c2df51b DJ |
517 | fprintf_filtered (stream, |
518 | "a variable with complex or multiple locations (DWARF2)"); | |
519 | return 1; | |
520 | } | |
521 | ||
a55cc764 DJ |
522 | |
523 | /* Describe the location of SYMBOL as an agent value in VALUE, generating | |
524 | any necessary bytecode in AX. | |
525 | ||
526 | NOTE drow/2003-02-26: This function is extremely minimal, because | |
527 | doing it correctly is extremely complicated and there is no | |
528 | publicly available stub with tracepoint support for me to test | |
529 | against. When there is one this function should be revisited. */ | |
530 | ||
0d53c4c4 | 531 | static void |
505e835d UW |
532 | locexpr_tracepoint_var_ref (struct symbol *symbol, struct gdbarch *gdbarch, |
533 | struct agent_expr *ax, struct axs_value *value) | |
a55cc764 DJ |
534 | { |
535 | struct dwarf2_locexpr_baton *dlbaton = SYMBOL_LOCATION_BATON (symbol); | |
536 | ||
505e835d UW |
537 | dwarf2_tracepoint_var_ref (symbol, gdbarch, ax, value, |
538 | dlbaton->data, dlbaton->size); | |
a55cc764 DJ |
539 | } |
540 | ||
4c2df51b DJ |
541 | /* The set of location functions used with the DWARF-2 expression |
542 | evaluator. */ | |
768a979c | 543 | const struct symbol_computed_ops dwarf2_locexpr_funcs = { |
4c2df51b DJ |
544 | locexpr_read_variable, |
545 | locexpr_read_needs_frame, | |
546 | locexpr_describe_location, | |
a55cc764 | 547 | locexpr_tracepoint_var_ref |
4c2df51b | 548 | }; |
0d53c4c4 DJ |
549 | |
550 | ||
551 | /* Wrapper functions for location lists. These generally find | |
552 | the appropriate location expression and call something above. */ | |
553 | ||
554 | /* Return the value of SYMBOL in FRAME using the DWARF-2 expression | |
555 | evaluator to calculate the location. */ | |
556 | static struct value * | |
557 | loclist_read_variable (struct symbol *symbol, struct frame_info *frame) | |
558 | { | |
559 | struct dwarf2_loclist_baton *dlbaton = SYMBOL_LOCATION_BATON (symbol); | |
560 | struct value *val; | |
852483bc | 561 | gdb_byte *data; |
b6b08ebf | 562 | size_t size; |
0d53c4c4 DJ |
563 | |
564 | data = find_location_expression (dlbaton, &size, | |
22c6caba JW |
565 | frame ? get_frame_address_in_block (frame) |
566 | : 0); | |
0d53c4c4 | 567 | if (data == NULL) |
806048c6 DJ |
568 | { |
569 | val = allocate_value (SYMBOL_TYPE (symbol)); | |
570 | VALUE_LVAL (val) = not_lval; | |
571 | set_value_optimized_out (val, 1); | |
572 | } | |
573 | else | |
574 | val = dwarf2_evaluate_loc_desc (symbol, frame, data, size, | |
ae0d2f24 | 575 | dlbaton->per_cu); |
0d53c4c4 DJ |
576 | |
577 | return val; | |
578 | } | |
579 | ||
580 | /* Return non-zero iff we need a frame to evaluate SYMBOL. */ | |
581 | static int | |
582 | loclist_read_needs_frame (struct symbol *symbol) | |
583 | { | |
584 | /* If there's a location list, then assume we need to have a frame | |
585 | to choose the appropriate location expression. With tracking of | |
586 | global variables this is not necessarily true, but such tracking | |
587 | is disabled in GCC at the moment until we figure out how to | |
588 | represent it. */ | |
589 | ||
590 | return 1; | |
591 | } | |
592 | ||
593 | /* Print a natural-language description of SYMBOL to STREAM. */ | |
594 | static int | |
595 | loclist_describe_location (struct symbol *symbol, struct ui_file *stream) | |
596 | { | |
597 | /* FIXME: Could print the entire list of locations. */ | |
598 | fprintf_filtered (stream, "a variable with multiple locations"); | |
599 | return 1; | |
600 | } | |
601 | ||
602 | /* Describe the location of SYMBOL as an agent value in VALUE, generating | |
603 | any necessary bytecode in AX. */ | |
604 | static void | |
505e835d UW |
605 | loclist_tracepoint_var_ref (struct symbol *symbol, struct gdbarch *gdbarch, |
606 | struct agent_expr *ax, struct axs_value *value) | |
0d53c4c4 DJ |
607 | { |
608 | struct dwarf2_loclist_baton *dlbaton = SYMBOL_LOCATION_BATON (symbol); | |
852483bc | 609 | gdb_byte *data; |
b6b08ebf | 610 | size_t size; |
0d53c4c4 DJ |
611 | |
612 | data = find_location_expression (dlbaton, &size, ax->scope); | |
613 | if (data == NULL) | |
8a3fe4f8 | 614 | error (_("Variable \"%s\" is not available."), SYMBOL_NATURAL_NAME (symbol)); |
0d53c4c4 | 615 | |
505e835d | 616 | dwarf2_tracepoint_var_ref (symbol, gdbarch, ax, value, data, size); |
0d53c4c4 DJ |
617 | } |
618 | ||
619 | /* The set of location functions used with the DWARF-2 expression | |
620 | evaluator and location lists. */ | |
768a979c | 621 | const struct symbol_computed_ops dwarf2_loclist_funcs = { |
0d53c4c4 DJ |
622 | loclist_read_variable, |
623 | loclist_read_needs_frame, | |
624 | loclist_describe_location, | |
625 | loclist_tracepoint_var_ref | |
626 | }; |