Commit | Line | Data |
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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 | { | |
305 | /* We haven't implemented splicing together pieces from | |
306 | arbitrary sources yet. */ | |
8a3fe4f8 AC |
307 | error (_("The value of variable '%s' is distributed across several\n" |
308 | "locations, and GDB cannot access its value.\n"), | |
87808bd6 JB |
309 | SYMBOL_NATURAL_NAME (var)); |
310 | } | |
311 | else if (ctx->in_reg) | |
051caad9 | 312 | { |
5ca2e327 JB |
313 | CORE_ADDR dwarf_regnum = dwarf_expr_fetch (ctx, 0); |
314 | int gdb_regnum = DWARF2_REG_TO_REGNUM (dwarf_regnum); | |
315 | retval = value_from_register (SYMBOL_TYPE (var), gdb_regnum, frame); | |
051caad9 | 316 | } |
4c2df51b DJ |
317 | else |
318 | { | |
5ca2e327 JB |
319 | CORE_ADDR address = dwarf_expr_fetch (ctx, 0); |
320 | ||
61fbb938 | 321 | retval = allocate_value (SYMBOL_TYPE (var)); |
4c2df51b | 322 | VALUE_LVAL (retval) = lval_memory; |
dfa52d88 | 323 | set_value_lazy (retval, 1); |
5ca2e327 | 324 | VALUE_ADDRESS (retval) = address; |
4c2df51b DJ |
325 | } |
326 | ||
327 | free_dwarf_expr_context (ctx); | |
328 | ||
329 | return retval; | |
330 | } | |
331 | ||
332 | ||
333 | ||
334 | ||
335 | \f | |
336 | /* Helper functions and baton for dwarf2_loc_desc_needs_frame. */ | |
337 | ||
338 | struct needs_frame_baton | |
339 | { | |
340 | int needs_frame; | |
341 | }; | |
342 | ||
343 | /* Reads from registers do require a frame. */ | |
344 | static CORE_ADDR | |
61fbb938 | 345 | needs_frame_read_reg (void *baton, int regnum) |
4c2df51b DJ |
346 | { |
347 | struct needs_frame_baton *nf_baton = baton; | |
348 | nf_baton->needs_frame = 1; | |
349 | return 1; | |
350 | } | |
351 | ||
352 | /* Reads from memory do not require a frame. */ | |
353 | static void | |
852483bc | 354 | needs_frame_read_mem (void *baton, gdb_byte *buf, CORE_ADDR addr, size_t len) |
4c2df51b DJ |
355 | { |
356 | memset (buf, 0, len); | |
357 | } | |
358 | ||
359 | /* Frame-relative accesses do require a frame. */ | |
360 | static void | |
852483bc | 361 | needs_frame_frame_base (void *baton, gdb_byte **start, size_t * length) |
4c2df51b | 362 | { |
852483bc | 363 | static gdb_byte lit0 = DW_OP_lit0; |
4c2df51b DJ |
364 | struct needs_frame_baton *nf_baton = baton; |
365 | ||
366 | *start = &lit0; | |
367 | *length = 1; | |
368 | ||
369 | nf_baton->needs_frame = 1; | |
370 | } | |
371 | ||
372 | /* Thread-local accesses do require a frame. */ | |
373 | static CORE_ADDR | |
374 | needs_frame_tls_address (void *baton, CORE_ADDR offset) | |
375 | { | |
376 | struct needs_frame_baton *nf_baton = baton; | |
377 | nf_baton->needs_frame = 1; | |
378 | return 1; | |
379 | } | |
380 | ||
381 | /* Return non-zero iff the location expression at DATA (length SIZE) | |
382 | requires a frame to evaluate. */ | |
383 | ||
384 | static int | |
852483bc | 385 | dwarf2_loc_desc_needs_frame (gdb_byte *data, unsigned short size) |
4c2df51b DJ |
386 | { |
387 | struct needs_frame_baton baton; | |
388 | struct dwarf_expr_context *ctx; | |
f630a401 | 389 | int in_reg; |
4c2df51b DJ |
390 | |
391 | baton.needs_frame = 0; | |
392 | ||
393 | ctx = new_dwarf_expr_context (); | |
394 | ctx->baton = &baton; | |
395 | ctx->read_reg = needs_frame_read_reg; | |
396 | ctx->read_mem = needs_frame_read_mem; | |
397 | ctx->get_frame_base = needs_frame_frame_base; | |
398 | ctx->get_tls_address = needs_frame_tls_address; | |
399 | ||
400 | dwarf_expr_eval (ctx, data, size); | |
401 | ||
f630a401 DJ |
402 | in_reg = ctx->in_reg; |
403 | ||
87808bd6 JB |
404 | if (ctx->num_pieces > 0) |
405 | { | |
406 | int i; | |
407 | ||
408 | /* If the location has several pieces, and any of them are in | |
409 | registers, then we will need a frame to fetch them from. */ | |
410 | for (i = 0; i < ctx->num_pieces; i++) | |
411 | if (ctx->pieces[i].in_reg) | |
412 | in_reg = 1; | |
413 | } | |
414 | ||
4c2df51b DJ |
415 | free_dwarf_expr_context (ctx); |
416 | ||
f630a401 | 417 | return baton.needs_frame || in_reg; |
4c2df51b DJ |
418 | } |
419 | ||
0d53c4c4 | 420 | static void |
852483bc MK |
421 | dwarf2_tracepoint_var_ref (struct symbol *symbol, struct agent_expr *ax, |
422 | struct axs_value *value, gdb_byte *data, | |
0d53c4c4 DJ |
423 | int size) |
424 | { | |
425 | if (size == 0) | |
8a3fe4f8 | 426 | error (_("Symbol \"%s\" has been optimized out."), |
0d53c4c4 DJ |
427 | SYMBOL_PRINT_NAME (symbol)); |
428 | ||
429 | if (size == 1 | |
430 | && data[0] >= DW_OP_reg0 | |
431 | && data[0] <= DW_OP_reg31) | |
432 | { | |
433 | value->kind = axs_lvalue_register; | |
434 | value->u.reg = data[0] - DW_OP_reg0; | |
435 | } | |
436 | else if (data[0] == DW_OP_regx) | |
437 | { | |
438 | ULONGEST reg; | |
439 | read_uleb128 (data + 1, data + size, ®); | |
440 | value->kind = axs_lvalue_register; | |
441 | value->u.reg = reg; | |
442 | } | |
443 | else if (data[0] == DW_OP_fbreg) | |
444 | { | |
445 | /* And this is worse than just minimal; we should honor the frame base | |
446 | as above. */ | |
447 | int frame_reg; | |
448 | LONGEST frame_offset; | |
852483bc | 449 | gdb_byte *buf_end; |
0d53c4c4 DJ |
450 | |
451 | buf_end = read_sleb128 (data + 1, data + size, &frame_offset); | |
452 | if (buf_end != data + size) | |
8a3fe4f8 | 453 | error (_("Unexpected opcode after DW_OP_fbreg for symbol \"%s\"."), |
0d53c4c4 | 454 | SYMBOL_PRINT_NAME (symbol)); |
4c2df51b | 455 | |
0d53c4c4 DJ |
456 | TARGET_VIRTUAL_FRAME_POINTER (ax->scope, &frame_reg, &frame_offset); |
457 | ax_reg (ax, frame_reg); | |
458 | ax_const_l (ax, frame_offset); | |
459 | ax_simple (ax, aop_add); | |
4c2df51b | 460 | |
0d53c4c4 DJ |
461 | ax_const_l (ax, frame_offset); |
462 | ax_simple (ax, aop_add); | |
463 | value->kind = axs_lvalue_memory; | |
464 | } | |
465 | else | |
8a3fe4f8 | 466 | error (_("Unsupported DWARF opcode in the location of \"%s\"."), |
0d53c4c4 DJ |
467 | SYMBOL_PRINT_NAME (symbol)); |
468 | } | |
4c2df51b DJ |
469 | \f |
470 | /* Return the value of SYMBOL in FRAME using the DWARF-2 expression | |
471 | evaluator to calculate the location. */ | |
472 | static struct value * | |
473 | locexpr_read_variable (struct symbol *symbol, struct frame_info *frame) | |
474 | { | |
475 | struct dwarf2_locexpr_baton *dlbaton = SYMBOL_LOCATION_BATON (symbol); | |
476 | struct value *val; | |
477 | val = dwarf2_evaluate_loc_desc (symbol, frame, dlbaton->data, dlbaton->size, | |
478 | dlbaton->objfile); | |
479 | ||
480 | return val; | |
481 | } | |
482 | ||
483 | /* Return non-zero iff we need a frame to evaluate SYMBOL. */ | |
484 | static int | |
485 | locexpr_read_needs_frame (struct symbol *symbol) | |
486 | { | |
487 | struct dwarf2_locexpr_baton *dlbaton = SYMBOL_LOCATION_BATON (symbol); | |
488 | return dwarf2_loc_desc_needs_frame (dlbaton->data, dlbaton->size); | |
489 | } | |
490 | ||
491 | /* Print a natural-language description of SYMBOL to STREAM. */ | |
492 | static int | |
493 | locexpr_describe_location (struct symbol *symbol, struct ui_file *stream) | |
494 | { | |
495 | /* FIXME: be more extensive. */ | |
496 | struct dwarf2_locexpr_baton *dlbaton = SYMBOL_LOCATION_BATON (symbol); | |
497 | ||
498 | if (dlbaton->size == 1 | |
499 | && dlbaton->data[0] >= DW_OP_reg0 | |
500 | && dlbaton->data[0] <= DW_OP_reg31) | |
501 | { | |
502 | int regno = DWARF2_REG_TO_REGNUM (dlbaton->data[0] - DW_OP_reg0); | |
503 | fprintf_filtered (stream, | |
504 | "a variable in register %s", REGISTER_NAME (regno)); | |
505 | return 1; | |
506 | } | |
507 | ||
c3228f12 EZ |
508 | /* The location expression for a TLS variable looks like this (on a |
509 | 64-bit LE machine): | |
510 | ||
511 | DW_AT_location : 10 byte block: 3 4 0 0 0 0 0 0 0 e0 | |
512 | (DW_OP_addr: 4; DW_OP_GNU_push_tls_address) | |
513 | ||
514 | 0x3 is the encoding for DW_OP_addr, which has an operand as long | |
515 | as the size of an address on the target machine (here is 8 | |
516 | bytes). 0xe0 is the encoding for DW_OP_GNU_push_tls_address. | |
517 | The operand represents the offset at which the variable is within | |
518 | the thread local storage. */ | |
519 | ||
520 | if (dlbaton->size > 1 | |
521 | && dlbaton->data[dlbaton->size - 1] == DW_OP_GNU_push_tls_address) | |
522 | if (dlbaton->data[0] == DW_OP_addr) | |
523 | { | |
524 | int bytes_read; | |
525 | CORE_ADDR offset = dwarf2_read_address (&dlbaton->data[1], | |
c193f044 | 526 | &dlbaton->data[dlbaton->size - 1], |
c3228f12 EZ |
527 | &bytes_read); |
528 | fprintf_filtered (stream, | |
32ffcbed | 529 | "a thread-local variable at offset %s in the " |
c3228f12 EZ |
530 | "thread-local storage for `%s'", |
531 | paddr_nz (offset), dlbaton->objfile->name); | |
532 | return 1; | |
533 | } | |
534 | ||
535 | ||
4c2df51b DJ |
536 | fprintf_filtered (stream, |
537 | "a variable with complex or multiple locations (DWARF2)"); | |
538 | return 1; | |
539 | } | |
540 | ||
a55cc764 DJ |
541 | |
542 | /* Describe the location of SYMBOL as an agent value in VALUE, generating | |
543 | any necessary bytecode in AX. | |
544 | ||
545 | NOTE drow/2003-02-26: This function is extremely minimal, because | |
546 | doing it correctly is extremely complicated and there is no | |
547 | publicly available stub with tracepoint support for me to test | |
548 | against. When there is one this function should be revisited. */ | |
549 | ||
0d53c4c4 | 550 | static void |
a55cc764 DJ |
551 | locexpr_tracepoint_var_ref (struct symbol * symbol, struct agent_expr * ax, |
552 | struct axs_value * value) | |
553 | { | |
554 | struct dwarf2_locexpr_baton *dlbaton = SYMBOL_LOCATION_BATON (symbol); | |
555 | ||
0d53c4c4 | 556 | dwarf2_tracepoint_var_ref (symbol, ax, value, dlbaton->data, dlbaton->size); |
a55cc764 DJ |
557 | } |
558 | ||
4c2df51b DJ |
559 | /* The set of location functions used with the DWARF-2 expression |
560 | evaluator. */ | |
a67af2b9 | 561 | const struct symbol_ops dwarf2_locexpr_funcs = { |
4c2df51b DJ |
562 | locexpr_read_variable, |
563 | locexpr_read_needs_frame, | |
564 | locexpr_describe_location, | |
a55cc764 | 565 | locexpr_tracepoint_var_ref |
4c2df51b | 566 | }; |
0d53c4c4 DJ |
567 | |
568 | ||
569 | /* Wrapper functions for location lists. These generally find | |
570 | the appropriate location expression and call something above. */ | |
571 | ||
572 | /* Return the value of SYMBOL in FRAME using the DWARF-2 expression | |
573 | evaluator to calculate the location. */ | |
574 | static struct value * | |
575 | loclist_read_variable (struct symbol *symbol, struct frame_info *frame) | |
576 | { | |
577 | struct dwarf2_loclist_baton *dlbaton = SYMBOL_LOCATION_BATON (symbol); | |
578 | struct value *val; | |
852483bc | 579 | gdb_byte *data; |
b6b08ebf | 580 | size_t size; |
0d53c4c4 DJ |
581 | |
582 | data = find_location_expression (dlbaton, &size, | |
583 | frame ? get_frame_pc (frame) : 0); | |
584 | if (data == NULL) | |
806048c6 DJ |
585 | { |
586 | val = allocate_value (SYMBOL_TYPE (symbol)); | |
587 | VALUE_LVAL (val) = not_lval; | |
588 | set_value_optimized_out (val, 1); | |
589 | } | |
590 | else | |
591 | val = dwarf2_evaluate_loc_desc (symbol, frame, data, size, | |
592 | dlbaton->objfile); | |
0d53c4c4 DJ |
593 | |
594 | return val; | |
595 | } | |
596 | ||
597 | /* Return non-zero iff we need a frame to evaluate SYMBOL. */ | |
598 | static int | |
599 | loclist_read_needs_frame (struct symbol *symbol) | |
600 | { | |
601 | /* If there's a location list, then assume we need to have a frame | |
602 | to choose the appropriate location expression. With tracking of | |
603 | global variables this is not necessarily true, but such tracking | |
604 | is disabled in GCC at the moment until we figure out how to | |
605 | represent it. */ | |
606 | ||
607 | return 1; | |
608 | } | |
609 | ||
610 | /* Print a natural-language description of SYMBOL to STREAM. */ | |
611 | static int | |
612 | loclist_describe_location (struct symbol *symbol, struct ui_file *stream) | |
613 | { | |
614 | /* FIXME: Could print the entire list of locations. */ | |
615 | fprintf_filtered (stream, "a variable with multiple locations"); | |
616 | return 1; | |
617 | } | |
618 | ||
619 | /* Describe the location of SYMBOL as an agent value in VALUE, generating | |
620 | any necessary bytecode in AX. */ | |
621 | static void | |
622 | loclist_tracepoint_var_ref (struct symbol * symbol, struct agent_expr * ax, | |
623 | struct axs_value * value) | |
624 | { | |
625 | struct dwarf2_loclist_baton *dlbaton = SYMBOL_LOCATION_BATON (symbol); | |
852483bc | 626 | gdb_byte *data; |
b6b08ebf | 627 | size_t size; |
0d53c4c4 DJ |
628 | |
629 | data = find_location_expression (dlbaton, &size, ax->scope); | |
630 | if (data == NULL) | |
8a3fe4f8 | 631 | error (_("Variable \"%s\" is not available."), SYMBOL_NATURAL_NAME (symbol)); |
0d53c4c4 DJ |
632 | |
633 | dwarf2_tracepoint_var_ref (symbol, ax, value, data, size); | |
634 | } | |
635 | ||
636 | /* The set of location functions used with the DWARF-2 expression | |
637 | evaluator and location lists. */ | |
a67af2b9 | 638 | const struct symbol_ops dwarf2_loclist_funcs = { |
0d53c4c4 DJ |
639 | loclist_read_variable, |
640 | loclist_read_needs_frame, | |
641 | loclist_describe_location, | |
642 | loclist_tracepoint_var_ref | |
643 | }; |