Commit | Line | Data |
---|---|---|
4c2df51b | 1 | /* DWARF 2 location expression support for GDB. |
feb13ab0 AC |
2 | |
3 | Copyright 2003, 2005 Free Software Foundation, Inc. | |
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 | |
21 | Foundation, Inc., 59 Temple Place - Suite 330, | |
22 | Boston, MA 02111-1307, USA. */ | |
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 | ||
43 | #ifndef DWARF2_REG_TO_REGNUM | |
44 | #define DWARF2_REG_TO_REGNUM(REG) (REG) | |
45 | #endif | |
46 | ||
0d53c4c4 DJ |
47 | /* A helper function for dealing with location lists. Given a |
48 | symbol baton (BATON) and a pc value (PC), find the appropriate | |
49 | location expression, set *LOCEXPR_LENGTH, and return a pointer | |
50 | to the beginning of the expression. Returns NULL on failure. | |
51 | ||
52 | For now, only return the first matching location expression; there | |
53 | can be more than one in the list. */ | |
54 | ||
852483bc | 55 | static gdb_byte * |
0d53c4c4 | 56 | find_location_expression (struct dwarf2_loclist_baton *baton, |
b6b08ebf | 57 | size_t *locexpr_length, CORE_ADDR pc) |
0d53c4c4 | 58 | { |
0d53c4c4 | 59 | CORE_ADDR low, high; |
852483bc MK |
60 | gdb_byte *loc_ptr, *buf_end; |
61 | int length; | |
62 | unsigned int addr_size = TARGET_ADDR_BIT / TARGET_CHAR_BIT; | |
0d53c4c4 | 63 | CORE_ADDR base_mask = ~(~(CORE_ADDR)1 << (addr_size * 8 - 1)); |
8edfa926 BM |
64 | /* Adjust base_address for relocatable objects. */ |
65 | CORE_ADDR base_offset = ANOFFSET (baton->objfile->section_offsets, | |
66 | SECT_OFF_TEXT (baton->objfile)); | |
67 | CORE_ADDR base_address = baton->base_address + base_offset; | |
0d53c4c4 DJ |
68 | |
69 | loc_ptr = baton->data; | |
70 | buf_end = baton->data + baton->size; | |
71 | ||
72 | while (1) | |
73 | { | |
74 | low = dwarf2_read_address (loc_ptr, buf_end, &length); | |
75 | loc_ptr += length; | |
76 | high = dwarf2_read_address (loc_ptr, buf_end, &length); | |
77 | loc_ptr += length; | |
78 | ||
79 | /* An end-of-list entry. */ | |
80 | if (low == 0 && high == 0) | |
81 | return NULL; | |
82 | ||
83 | /* A base-address-selection entry. */ | |
84 | if ((low & base_mask) == base_mask) | |
85 | { | |
86 | base_address = high; | |
87 | continue; | |
88 | } | |
89 | ||
90 | /* Otherwise, a location expression entry. */ | |
91 | low += base_address; | |
92 | high += base_address; | |
93 | ||
94 | length = extract_unsigned_integer (loc_ptr, 2); | |
95 | loc_ptr += 2; | |
96 | ||
97 | if (pc >= low && pc < high) | |
98 | { | |
99 | *locexpr_length = length; | |
100 | return loc_ptr; | |
101 | } | |
102 | ||
103 | loc_ptr += length; | |
104 | } | |
105 | } | |
106 | ||
4c2df51b DJ |
107 | /* This is the baton used when performing dwarf2 expression |
108 | evaluation. */ | |
109 | struct dwarf_expr_baton | |
110 | { | |
111 | struct frame_info *frame; | |
112 | struct objfile *objfile; | |
113 | }; | |
114 | ||
115 | /* Helper functions for dwarf2_evaluate_loc_desc. */ | |
116 | ||
117 | /* Using the frame specified in BATON, read register REGNUM. The lval | |
118 | type will be returned in LVALP, and for lval_memory the register | |
119 | save address will be returned in ADDRP. */ | |
120 | static CORE_ADDR | |
61fbb938 | 121 | dwarf_expr_read_reg (void *baton, int dwarf_regnum) |
4c2df51b | 122 | { |
4c2df51b | 123 | struct dwarf_expr_baton *debaton = (struct dwarf_expr_baton *) baton; |
61fbb938 DJ |
124 | CORE_ADDR result, save_addr; |
125 | enum lval_type lval_type; | |
852483bc | 126 | gdb_byte *buf; |
e4adbba9 DJ |
127 | int optimized, regnum, realnum, regsize; |
128 | ||
129 | regnum = DWARF2_REG_TO_REGNUM (dwarf_regnum); | |
130 | regsize = register_size (current_gdbarch, regnum); | |
852483bc | 131 | buf = alloca (regsize); |
4c2df51b | 132 | |
61fbb938 DJ |
133 | frame_register (debaton->frame, regnum, &optimized, &lval_type, &save_addr, |
134 | &realnum, buf); | |
af1342ab AC |
135 | /* NOTE: cagney/2003-05-22: This extract is assuming that a DWARF 2 |
136 | address is always unsigned. That may or may not be true. */ | |
137 | result = extract_unsigned_integer (buf, regsize); | |
4c2df51b DJ |
138 | |
139 | return result; | |
140 | } | |
141 | ||
142 | /* Read memory at ADDR (length LEN) into BUF. */ | |
143 | ||
144 | static void | |
852483bc | 145 | dwarf_expr_read_mem (void *baton, gdb_byte *buf, CORE_ADDR addr, size_t len) |
4c2df51b DJ |
146 | { |
147 | read_memory (addr, buf, len); | |
148 | } | |
149 | ||
150 | /* Using the frame specified in BATON, find the location expression | |
151 | describing the frame base. Return a pointer to it in START and | |
152 | its length in LENGTH. */ | |
153 | static void | |
852483bc | 154 | dwarf_expr_frame_base (void *baton, gdb_byte **start, size_t * length) |
4c2df51b | 155 | { |
da62e633 AC |
156 | /* FIXME: cagney/2003-03-26: This code should be using |
157 | get_frame_base_address(), and then implement a dwarf2 specific | |
158 | this_base method. */ | |
4c2df51b | 159 | struct symbol *framefunc; |
4c2df51b | 160 | struct dwarf_expr_baton *debaton = (struct dwarf_expr_baton *) baton; |
0d53c4c4 | 161 | |
4c2df51b | 162 | framefunc = get_frame_function (debaton->frame); |
0d53c4c4 | 163 | |
a67af2b9 | 164 | if (SYMBOL_OPS (framefunc) == &dwarf2_loclist_funcs) |
0d53c4c4 DJ |
165 | { |
166 | struct dwarf2_loclist_baton *symbaton; | |
167 | symbaton = SYMBOL_LOCATION_BATON (framefunc); | |
168 | *start = find_location_expression (symbaton, length, | |
169 | get_frame_pc (debaton->frame)); | |
170 | } | |
171 | else | |
172 | { | |
173 | struct dwarf2_locexpr_baton *symbaton; | |
174 | symbaton = SYMBOL_LOCATION_BATON (framefunc); | |
175 | *length = symbaton->size; | |
176 | *start = symbaton->data; | |
177 | } | |
178 | ||
179 | if (*start == NULL) | |
8a3fe4f8 | 180 | error (_("Could not find the frame base for \"%s\"."), |
0d53c4c4 | 181 | SYMBOL_NATURAL_NAME (framefunc)); |
4c2df51b DJ |
182 | } |
183 | ||
184 | /* Using the objfile specified in BATON, find the address for the | |
185 | current thread's thread-local storage with offset OFFSET. */ | |
186 | static CORE_ADDR | |
187 | dwarf_expr_tls_address (void *baton, CORE_ADDR offset) | |
188 | { | |
189 | struct dwarf_expr_baton *debaton = (struct dwarf_expr_baton *) baton; | |
4dd04433 | 190 | volatile CORE_ADDR addr = 0; |
4c2df51b | 191 | |
b2756930 KB |
192 | if (target_get_thread_local_address_p () |
193 | && gdbarch_fetch_tls_load_module_address_p (current_gdbarch)) | |
93ad78a7 KB |
194 | { |
195 | ptid_t ptid = inferior_ptid; | |
196 | struct objfile *objfile = debaton->objfile; | |
71fff37b | 197 | volatile struct gdb_exception ex; |
93ad78a7 KB |
198 | |
199 | TRY_CATCH (ex, RETURN_MASK_ALL) | |
200 | { | |
b2756930 KB |
201 | CORE_ADDR lm_addr; |
202 | ||
203 | /* Fetch the load module address for this objfile. */ | |
204 | lm_addr = gdbarch_fetch_tls_load_module_address (current_gdbarch, | |
205 | objfile); | |
206 | /* If it's 0, throw the appropriate exception. */ | |
207 | if (lm_addr == 0) | |
109c3e39 AC |
208 | throw_error (TLS_LOAD_MODULE_NOT_FOUND_ERROR, |
209 | _("TLS load module not found")); | |
b2756930 KB |
210 | |
211 | addr = target_get_thread_local_address (ptid, lm_addr, offset); | |
93ad78a7 KB |
212 | } |
213 | /* If an error occurred, print TLS related messages here. Otherwise, | |
214 | throw the error to some higher catcher. */ | |
215 | if (ex.reason < 0) | |
216 | { | |
217 | int objfile_is_library = (objfile->flags & OBJF_SHARED); | |
218 | ||
219 | switch (ex.error) | |
220 | { | |
221 | case TLS_NO_LIBRARY_SUPPORT_ERROR: | |
222 | error (_("Cannot find thread-local variables in this thread library.")); | |
223 | break; | |
224 | case TLS_LOAD_MODULE_NOT_FOUND_ERROR: | |
225 | if (objfile_is_library) | |
226 | error (_("Cannot find shared library `%s' in dynamic" | |
227 | " linker's load module list"), objfile->name); | |
228 | else | |
229 | error (_("Cannot find executable file `%s' in dynamic" | |
230 | " linker's load module list"), objfile->name); | |
231 | break; | |
232 | case TLS_NOT_ALLOCATED_YET_ERROR: | |
233 | if (objfile_is_library) | |
234 | error (_("The inferior has not yet allocated storage for" | |
235 | " thread-local variables in\n" | |
236 | "the shared library `%s'\n" | |
237 | "for %s"), | |
238 | objfile->name, target_pid_to_str (ptid)); | |
239 | else | |
240 | error (_("The inferior has not yet allocated storage for" | |
241 | " thread-local variables in\n" | |
242 | "the executable `%s'\n" | |
243 | "for %s"), | |
244 | objfile->name, target_pid_to_str (ptid)); | |
245 | break; | |
246 | case TLS_GENERIC_ERROR: | |
247 | if (objfile_is_library) | |
248 | error (_("Cannot find thread-local storage for %s, " | |
249 | "shared library %s:\n%s"), | |
250 | target_pid_to_str (ptid), | |
251 | objfile->name, ex.message); | |
252 | else | |
253 | error (_("Cannot find thread-local storage for %s, " | |
254 | "executable file %s:\n%s"), | |
255 | target_pid_to_str (ptid), | |
256 | objfile->name, ex.message); | |
257 | break; | |
258 | default: | |
259 | throw_exception (ex); | |
260 | break; | |
261 | } | |
262 | } | |
263 | } | |
c3228f12 EZ |
264 | /* It wouldn't be wrong here to try a gdbarch method, too; finding |
265 | TLS is an ABI-specific thing. But we don't do that yet. */ | |
4c2df51b | 266 | else |
8a3fe4f8 | 267 | error (_("Cannot find thread-local variables on this target")); |
4c2df51b DJ |
268 | |
269 | return addr; | |
270 | } | |
271 | ||
272 | /* Evaluate a location description, starting at DATA and with length | |
273 | SIZE, to find the current location of variable VAR in the context | |
274 | of FRAME. */ | |
275 | static struct value * | |
276 | dwarf2_evaluate_loc_desc (struct symbol *var, struct frame_info *frame, | |
852483bc | 277 | gdb_byte *data, unsigned short size, |
4c2df51b DJ |
278 | struct objfile *objfile) |
279 | { | |
87808bd6 | 280 | struct gdbarch *arch = get_frame_arch (frame); |
4c2df51b DJ |
281 | struct value *retval; |
282 | struct dwarf_expr_baton baton; | |
283 | struct dwarf_expr_context *ctx; | |
284 | ||
0d53c4c4 DJ |
285 | if (size == 0) |
286 | { | |
287 | retval = allocate_value (SYMBOL_TYPE (var)); | |
288 | VALUE_LVAL (retval) = not_lval; | |
feb13ab0 | 289 | set_value_optimized_out (retval, 1); |
0d53c4c4 DJ |
290 | } |
291 | ||
4c2df51b DJ |
292 | baton.frame = frame; |
293 | baton.objfile = objfile; | |
294 | ||
295 | ctx = new_dwarf_expr_context (); | |
296 | ctx->baton = &baton; | |
297 | ctx->read_reg = dwarf_expr_read_reg; | |
298 | ctx->read_mem = dwarf_expr_read_mem; | |
299 | ctx->get_frame_base = dwarf_expr_frame_base; | |
300 | ctx->get_tls_address = dwarf_expr_tls_address; | |
301 | ||
302 | dwarf_expr_eval (ctx, data, size); | |
87808bd6 JB |
303 | if (ctx->num_pieces > 0) |
304 | { | |
23572eca EZ |
305 | int i; |
306 | long offset = 0; | |
307 | bfd_byte *contents; | |
308 | ||
309 | retval = allocate_value (SYMBOL_TYPE (var)); | |
310 | contents = value_contents_raw (retval); | |
311 | for (i = 0; i < ctx->num_pieces; i++) | |
312 | { | |
313 | struct dwarf_expr_piece *p = &ctx->pieces[i]; | |
314 | if (p->in_reg) | |
315 | { | |
316 | bfd_byte regval[MAX_REGISTER_SIZE]; | |
317 | int gdb_regnum = DWARF2_REG_TO_REGNUM (p->value); | |
318 | get_frame_register (frame, gdb_regnum, regval); | |
319 | memcpy (contents + offset, regval, p->size); | |
320 | } | |
321 | else /* In memory? */ | |
322 | { | |
323 | read_memory (p->value, contents + offset, p->size); | |
324 | } | |
325 | offset += p->size; | |
326 | } | |
87808bd6 JB |
327 | } |
328 | else if (ctx->in_reg) | |
051caad9 | 329 | { |
5ca2e327 JB |
330 | CORE_ADDR dwarf_regnum = dwarf_expr_fetch (ctx, 0); |
331 | int gdb_regnum = DWARF2_REG_TO_REGNUM (dwarf_regnum); | |
332 | retval = value_from_register (SYMBOL_TYPE (var), gdb_regnum, frame); | |
051caad9 | 333 | } |
4c2df51b DJ |
334 | else |
335 | { | |
5ca2e327 JB |
336 | CORE_ADDR address = dwarf_expr_fetch (ctx, 0); |
337 | ||
61fbb938 | 338 | retval = allocate_value (SYMBOL_TYPE (var)); |
4c2df51b | 339 | VALUE_LVAL (retval) = lval_memory; |
dfa52d88 | 340 | set_value_lazy (retval, 1); |
5ca2e327 | 341 | VALUE_ADDRESS (retval) = address; |
4c2df51b DJ |
342 | } |
343 | ||
344 | free_dwarf_expr_context (ctx); | |
345 | ||
346 | return retval; | |
347 | } | |
348 | ||
349 | ||
350 | ||
351 | ||
352 | \f | |
353 | /* Helper functions and baton for dwarf2_loc_desc_needs_frame. */ | |
354 | ||
355 | struct needs_frame_baton | |
356 | { | |
357 | int needs_frame; | |
358 | }; | |
359 | ||
360 | /* Reads from registers do require a frame. */ | |
361 | static CORE_ADDR | |
61fbb938 | 362 | needs_frame_read_reg (void *baton, int regnum) |
4c2df51b DJ |
363 | { |
364 | struct needs_frame_baton *nf_baton = baton; | |
365 | nf_baton->needs_frame = 1; | |
366 | return 1; | |
367 | } | |
368 | ||
369 | /* Reads from memory do not require a frame. */ | |
370 | static void | |
852483bc | 371 | needs_frame_read_mem (void *baton, gdb_byte *buf, CORE_ADDR addr, size_t len) |
4c2df51b DJ |
372 | { |
373 | memset (buf, 0, len); | |
374 | } | |
375 | ||
376 | /* Frame-relative accesses do require a frame. */ | |
377 | static void | |
852483bc | 378 | needs_frame_frame_base (void *baton, gdb_byte **start, size_t * length) |
4c2df51b | 379 | { |
852483bc | 380 | static gdb_byte lit0 = DW_OP_lit0; |
4c2df51b DJ |
381 | struct needs_frame_baton *nf_baton = baton; |
382 | ||
383 | *start = &lit0; | |
384 | *length = 1; | |
385 | ||
386 | nf_baton->needs_frame = 1; | |
387 | } | |
388 | ||
389 | /* Thread-local accesses do require a frame. */ | |
390 | static CORE_ADDR | |
391 | needs_frame_tls_address (void *baton, CORE_ADDR offset) | |
392 | { | |
393 | struct needs_frame_baton *nf_baton = baton; | |
394 | nf_baton->needs_frame = 1; | |
395 | return 1; | |
396 | } | |
397 | ||
398 | /* Return non-zero iff the location expression at DATA (length SIZE) | |
399 | requires a frame to evaluate. */ | |
400 | ||
401 | static int | |
852483bc | 402 | dwarf2_loc_desc_needs_frame (gdb_byte *data, unsigned short size) |
4c2df51b DJ |
403 | { |
404 | struct needs_frame_baton baton; | |
405 | struct dwarf_expr_context *ctx; | |
f630a401 | 406 | int in_reg; |
4c2df51b DJ |
407 | |
408 | baton.needs_frame = 0; | |
409 | ||
410 | ctx = new_dwarf_expr_context (); | |
411 | ctx->baton = &baton; | |
412 | ctx->read_reg = needs_frame_read_reg; | |
413 | ctx->read_mem = needs_frame_read_mem; | |
414 | ctx->get_frame_base = needs_frame_frame_base; | |
415 | ctx->get_tls_address = needs_frame_tls_address; | |
416 | ||
417 | dwarf_expr_eval (ctx, data, size); | |
418 | ||
f630a401 DJ |
419 | in_reg = ctx->in_reg; |
420 | ||
87808bd6 JB |
421 | if (ctx->num_pieces > 0) |
422 | { | |
423 | int i; | |
424 | ||
425 | /* If the location has several pieces, and any of them are in | |
426 | registers, then we will need a frame to fetch them from. */ | |
427 | for (i = 0; i < ctx->num_pieces; i++) | |
428 | if (ctx->pieces[i].in_reg) | |
429 | in_reg = 1; | |
430 | } | |
431 | ||
4c2df51b DJ |
432 | free_dwarf_expr_context (ctx); |
433 | ||
f630a401 | 434 | return baton.needs_frame || in_reg; |
4c2df51b DJ |
435 | } |
436 | ||
0d53c4c4 | 437 | static void |
852483bc MK |
438 | dwarf2_tracepoint_var_ref (struct symbol *symbol, struct agent_expr *ax, |
439 | struct axs_value *value, gdb_byte *data, | |
0d53c4c4 DJ |
440 | int size) |
441 | { | |
442 | if (size == 0) | |
8a3fe4f8 | 443 | error (_("Symbol \"%s\" has been optimized out."), |
0d53c4c4 DJ |
444 | SYMBOL_PRINT_NAME (symbol)); |
445 | ||
446 | if (size == 1 | |
447 | && data[0] >= DW_OP_reg0 | |
448 | && data[0] <= DW_OP_reg31) | |
449 | { | |
450 | value->kind = axs_lvalue_register; | |
451 | value->u.reg = data[0] - DW_OP_reg0; | |
452 | } | |
453 | else if (data[0] == DW_OP_regx) | |
454 | { | |
455 | ULONGEST reg; | |
456 | read_uleb128 (data + 1, data + size, ®); | |
457 | value->kind = axs_lvalue_register; | |
458 | value->u.reg = reg; | |
459 | } | |
460 | else if (data[0] == DW_OP_fbreg) | |
461 | { | |
462 | /* And this is worse than just minimal; we should honor the frame base | |
463 | as above. */ | |
464 | int frame_reg; | |
465 | LONGEST frame_offset; | |
852483bc | 466 | gdb_byte *buf_end; |
0d53c4c4 DJ |
467 | |
468 | buf_end = read_sleb128 (data + 1, data + size, &frame_offset); | |
469 | if (buf_end != data + size) | |
8a3fe4f8 | 470 | error (_("Unexpected opcode after DW_OP_fbreg for symbol \"%s\"."), |
0d53c4c4 | 471 | SYMBOL_PRINT_NAME (symbol)); |
4c2df51b | 472 | |
0d53c4c4 DJ |
473 | TARGET_VIRTUAL_FRAME_POINTER (ax->scope, &frame_reg, &frame_offset); |
474 | ax_reg (ax, frame_reg); | |
475 | ax_const_l (ax, frame_offset); | |
476 | ax_simple (ax, aop_add); | |
4c2df51b | 477 | |
0d53c4c4 DJ |
478 | ax_const_l (ax, frame_offset); |
479 | ax_simple (ax, aop_add); | |
480 | value->kind = axs_lvalue_memory; | |
481 | } | |
482 | else | |
8a3fe4f8 | 483 | error (_("Unsupported DWARF opcode in the location of \"%s\"."), |
0d53c4c4 DJ |
484 | SYMBOL_PRINT_NAME (symbol)); |
485 | } | |
4c2df51b DJ |
486 | \f |
487 | /* Return the value of SYMBOL in FRAME using the DWARF-2 expression | |
488 | evaluator to calculate the location. */ | |
489 | static struct value * | |
490 | locexpr_read_variable (struct symbol *symbol, struct frame_info *frame) | |
491 | { | |
492 | struct dwarf2_locexpr_baton *dlbaton = SYMBOL_LOCATION_BATON (symbol); | |
493 | struct value *val; | |
494 | val = dwarf2_evaluate_loc_desc (symbol, frame, dlbaton->data, dlbaton->size, | |
495 | dlbaton->objfile); | |
496 | ||
497 | return val; | |
498 | } | |
499 | ||
500 | /* Return non-zero iff we need a frame to evaluate SYMBOL. */ | |
501 | static int | |
502 | locexpr_read_needs_frame (struct symbol *symbol) | |
503 | { | |
504 | struct dwarf2_locexpr_baton *dlbaton = SYMBOL_LOCATION_BATON (symbol); | |
505 | return dwarf2_loc_desc_needs_frame (dlbaton->data, dlbaton->size); | |
506 | } | |
507 | ||
508 | /* Print a natural-language description of SYMBOL to STREAM. */ | |
509 | static int | |
510 | locexpr_describe_location (struct symbol *symbol, struct ui_file *stream) | |
511 | { | |
512 | /* FIXME: be more extensive. */ | |
513 | struct dwarf2_locexpr_baton *dlbaton = SYMBOL_LOCATION_BATON (symbol); | |
514 | ||
515 | if (dlbaton->size == 1 | |
516 | && dlbaton->data[0] >= DW_OP_reg0 | |
517 | && dlbaton->data[0] <= DW_OP_reg31) | |
518 | { | |
519 | int regno = DWARF2_REG_TO_REGNUM (dlbaton->data[0] - DW_OP_reg0); | |
520 | fprintf_filtered (stream, | |
521 | "a variable in register %s", REGISTER_NAME (regno)); | |
522 | return 1; | |
523 | } | |
524 | ||
c3228f12 EZ |
525 | /* The location expression for a TLS variable looks like this (on a |
526 | 64-bit LE machine): | |
527 | ||
528 | DW_AT_location : 10 byte block: 3 4 0 0 0 0 0 0 0 e0 | |
529 | (DW_OP_addr: 4; DW_OP_GNU_push_tls_address) | |
530 | ||
531 | 0x3 is the encoding for DW_OP_addr, which has an operand as long | |
532 | as the size of an address on the target machine (here is 8 | |
533 | bytes). 0xe0 is the encoding for DW_OP_GNU_push_tls_address. | |
534 | The operand represents the offset at which the variable is within | |
535 | the thread local storage. */ | |
536 | ||
537 | if (dlbaton->size > 1 | |
538 | && dlbaton->data[dlbaton->size - 1] == DW_OP_GNU_push_tls_address) | |
539 | if (dlbaton->data[0] == DW_OP_addr) | |
540 | { | |
541 | int bytes_read; | |
542 | CORE_ADDR offset = dwarf2_read_address (&dlbaton->data[1], | |
c193f044 | 543 | &dlbaton->data[dlbaton->size - 1], |
c3228f12 EZ |
544 | &bytes_read); |
545 | fprintf_filtered (stream, | |
32ffcbed | 546 | "a thread-local variable at offset %s in the " |
c3228f12 EZ |
547 | "thread-local storage for `%s'", |
548 | paddr_nz (offset), dlbaton->objfile->name); | |
549 | return 1; | |
550 | } | |
551 | ||
552 | ||
4c2df51b DJ |
553 | fprintf_filtered (stream, |
554 | "a variable with complex or multiple locations (DWARF2)"); | |
555 | return 1; | |
556 | } | |
557 | ||
a55cc764 DJ |
558 | |
559 | /* Describe the location of SYMBOL as an agent value in VALUE, generating | |
560 | any necessary bytecode in AX. | |
561 | ||
562 | NOTE drow/2003-02-26: This function is extremely minimal, because | |
563 | doing it correctly is extremely complicated and there is no | |
564 | publicly available stub with tracepoint support for me to test | |
565 | against. When there is one this function should be revisited. */ | |
566 | ||
0d53c4c4 | 567 | static void |
a55cc764 DJ |
568 | locexpr_tracepoint_var_ref (struct symbol * symbol, struct agent_expr * ax, |
569 | struct axs_value * value) | |
570 | { | |
571 | struct dwarf2_locexpr_baton *dlbaton = SYMBOL_LOCATION_BATON (symbol); | |
572 | ||
0d53c4c4 | 573 | dwarf2_tracepoint_var_ref (symbol, ax, value, dlbaton->data, dlbaton->size); |
a55cc764 DJ |
574 | } |
575 | ||
4c2df51b DJ |
576 | /* The set of location functions used with the DWARF-2 expression |
577 | evaluator. */ | |
a67af2b9 | 578 | const struct symbol_ops dwarf2_locexpr_funcs = { |
4c2df51b DJ |
579 | locexpr_read_variable, |
580 | locexpr_read_needs_frame, | |
581 | locexpr_describe_location, | |
a55cc764 | 582 | locexpr_tracepoint_var_ref |
4c2df51b | 583 | }; |
0d53c4c4 DJ |
584 | |
585 | ||
586 | /* Wrapper functions for location lists. These generally find | |
587 | the appropriate location expression and call something above. */ | |
588 | ||
589 | /* Return the value of SYMBOL in FRAME using the DWARF-2 expression | |
590 | evaluator to calculate the location. */ | |
591 | static struct value * | |
592 | loclist_read_variable (struct symbol *symbol, struct frame_info *frame) | |
593 | { | |
594 | struct dwarf2_loclist_baton *dlbaton = SYMBOL_LOCATION_BATON (symbol); | |
595 | struct value *val; | |
852483bc | 596 | gdb_byte *data; |
b6b08ebf | 597 | size_t size; |
0d53c4c4 DJ |
598 | |
599 | data = find_location_expression (dlbaton, &size, | |
600 | frame ? get_frame_pc (frame) : 0); | |
601 | if (data == NULL) | |
806048c6 DJ |
602 | { |
603 | val = allocate_value (SYMBOL_TYPE (symbol)); | |
604 | VALUE_LVAL (val) = not_lval; | |
605 | set_value_optimized_out (val, 1); | |
606 | } | |
607 | else | |
608 | val = dwarf2_evaluate_loc_desc (symbol, frame, data, size, | |
609 | dlbaton->objfile); | |
0d53c4c4 DJ |
610 | |
611 | return val; | |
612 | } | |
613 | ||
614 | /* Return non-zero iff we need a frame to evaluate SYMBOL. */ | |
615 | static int | |
616 | loclist_read_needs_frame (struct symbol *symbol) | |
617 | { | |
618 | /* If there's a location list, then assume we need to have a frame | |
619 | to choose the appropriate location expression. With tracking of | |
620 | global variables this is not necessarily true, but such tracking | |
621 | is disabled in GCC at the moment until we figure out how to | |
622 | represent it. */ | |
623 | ||
624 | return 1; | |
625 | } | |
626 | ||
627 | /* Print a natural-language description of SYMBOL to STREAM. */ | |
628 | static int | |
629 | loclist_describe_location (struct symbol *symbol, struct ui_file *stream) | |
630 | { | |
631 | /* FIXME: Could print the entire list of locations. */ | |
632 | fprintf_filtered (stream, "a variable with multiple locations"); | |
633 | return 1; | |
634 | } | |
635 | ||
636 | /* Describe the location of SYMBOL as an agent value in VALUE, generating | |
637 | any necessary bytecode in AX. */ | |
638 | static void | |
639 | loclist_tracepoint_var_ref (struct symbol * symbol, struct agent_expr * ax, | |
640 | struct axs_value * value) | |
641 | { | |
642 | struct dwarf2_loclist_baton *dlbaton = SYMBOL_LOCATION_BATON (symbol); | |
852483bc | 643 | gdb_byte *data; |
b6b08ebf | 644 | size_t size; |
0d53c4c4 DJ |
645 | |
646 | data = find_location_expression (dlbaton, &size, ax->scope); | |
647 | if (data == NULL) | |
8a3fe4f8 | 648 | error (_("Variable \"%s\" is not available."), SYMBOL_NATURAL_NAME (symbol)); |
0d53c4c4 DJ |
649 | |
650 | dwarf2_tracepoint_var_ref (symbol, ax, value, data, size); | |
651 | } | |
652 | ||
653 | /* The set of location functions used with the DWARF-2 expression | |
654 | evaluator and location lists. */ | |
a67af2b9 | 655 | const struct symbol_ops dwarf2_loclist_funcs = { |
0d53c4c4 DJ |
656 | loclist_read_variable, |
657 | loclist_read_needs_frame, | |
658 | loclist_describe_location, | |
659 | loclist_tracepoint_var_ref | |
660 | }; |