1 /* DWARF 2 location expression support for GDB.
3 Copyright (C) 2003-2014 Free Software Foundation, Inc.
5 Contributed by Daniel Jacobowitz, MontaVista Software, Inc.
7 This file is part of GDB.
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 3 of the License, or
12 (at your option) any later version.
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.
19 You should have received a copy of the GNU General Public License
20 along with this program. If not, see <http://www.gnu.org/licenses/>. */
37 #include "dwarf2expr.h"
38 #include "dwarf2loc.h"
39 #include "dwarf2-frame.h"
40 #include "compile/compile.h"
42 extern int dwarf2_always_disassemble;
44 static const struct dwarf_expr_context_funcs dwarf_expr_ctx_funcs;
46 static struct value *dwarf2_evaluate_loc_desc_full (struct type *type,
47 struct frame_info *frame,
50 struct dwarf2_per_cu_data *per_cu,
53 /* Until these have formal names, we define these here.
54 ref: http://gcc.gnu.org/wiki/DebugFission
55 Each entry in .debug_loc.dwo begins with a byte that describes the entry,
56 and is then followed by data specific to that entry. */
60 /* Indicates the end of the list of entries. */
61 DEBUG_LOC_END_OF_LIST = 0,
63 /* This is followed by an unsigned LEB128 number that is an index into
64 .debug_addr and specifies the base address for all following entries. */
65 DEBUG_LOC_BASE_ADDRESS = 1,
67 /* This is followed by two unsigned LEB128 numbers that are indices into
68 .debug_addr and specify the beginning and ending addresses, and then
69 a normal location expression as in .debug_loc. */
70 DEBUG_LOC_START_END = 2,
72 /* This is followed by an unsigned LEB128 number that is an index into
73 .debug_addr and specifies the beginning address, and a 4 byte unsigned
74 number that specifies the length, and then a normal location expression
76 DEBUG_LOC_START_LENGTH = 3,
78 /* An internal value indicating there is insufficient data. */
79 DEBUG_LOC_BUFFER_OVERFLOW = -1,
81 /* An internal value indicating an invalid kind of entry was found. */
82 DEBUG_LOC_INVALID_ENTRY = -2
85 /* Helper function which throws an error if a synthetic pointer is
89 invalid_synthetic_pointer (void)
91 error (_("access outside bounds of object "
92 "referenced via synthetic pointer"));
95 /* Decode the addresses in a non-dwo .debug_loc entry.
96 A pointer to the next byte to examine is returned in *NEW_PTR.
97 The encoded low,high addresses are return in *LOW,*HIGH.
98 The result indicates the kind of entry found. */
100 static enum debug_loc_kind
101 decode_debug_loc_addresses (const gdb_byte *loc_ptr, const gdb_byte *buf_end,
102 const gdb_byte **new_ptr,
103 CORE_ADDR *low, CORE_ADDR *high,
104 enum bfd_endian byte_order,
105 unsigned int addr_size,
108 CORE_ADDR base_mask = ~(~(CORE_ADDR)1 << (addr_size * 8 - 1));
110 if (buf_end - loc_ptr < 2 * addr_size)
111 return DEBUG_LOC_BUFFER_OVERFLOW;
114 *low = extract_signed_integer (loc_ptr, addr_size, byte_order);
116 *low = extract_unsigned_integer (loc_ptr, addr_size, byte_order);
117 loc_ptr += addr_size;
120 *high = extract_signed_integer (loc_ptr, addr_size, byte_order);
122 *high = extract_unsigned_integer (loc_ptr, addr_size, byte_order);
123 loc_ptr += addr_size;
127 /* A base-address-selection entry. */
128 if ((*low & base_mask) == base_mask)
129 return DEBUG_LOC_BASE_ADDRESS;
131 /* An end-of-list entry. */
132 if (*low == 0 && *high == 0)
133 return DEBUG_LOC_END_OF_LIST;
135 return DEBUG_LOC_START_END;
138 /* Decode the addresses in .debug_loc.dwo entry.
139 A pointer to the next byte to examine is returned in *NEW_PTR.
140 The encoded low,high addresses are return in *LOW,*HIGH.
141 The result indicates the kind of entry found. */
143 static enum debug_loc_kind
144 decode_debug_loc_dwo_addresses (struct dwarf2_per_cu_data *per_cu,
145 const gdb_byte *loc_ptr,
146 const gdb_byte *buf_end,
147 const gdb_byte **new_ptr,
148 CORE_ADDR *low, CORE_ADDR *high,
149 enum bfd_endian byte_order)
151 uint64_t low_index, high_index;
153 if (loc_ptr == buf_end)
154 return DEBUG_LOC_BUFFER_OVERFLOW;
158 case DEBUG_LOC_END_OF_LIST:
160 return DEBUG_LOC_END_OF_LIST;
161 case DEBUG_LOC_BASE_ADDRESS:
163 loc_ptr = gdb_read_uleb128 (loc_ptr, buf_end, &high_index);
165 return DEBUG_LOC_BUFFER_OVERFLOW;
166 *high = dwarf2_read_addr_index (per_cu, high_index);
168 return DEBUG_LOC_BASE_ADDRESS;
169 case DEBUG_LOC_START_END:
170 loc_ptr = gdb_read_uleb128 (loc_ptr, buf_end, &low_index);
172 return DEBUG_LOC_BUFFER_OVERFLOW;
173 *low = dwarf2_read_addr_index (per_cu, low_index);
174 loc_ptr = gdb_read_uleb128 (loc_ptr, buf_end, &high_index);
176 return DEBUG_LOC_BUFFER_OVERFLOW;
177 *high = dwarf2_read_addr_index (per_cu, high_index);
179 return DEBUG_LOC_START_END;
180 case DEBUG_LOC_START_LENGTH:
181 loc_ptr = gdb_read_uleb128 (loc_ptr, buf_end, &low_index);
183 return DEBUG_LOC_BUFFER_OVERFLOW;
184 *low = dwarf2_read_addr_index (per_cu, low_index);
185 if (loc_ptr + 4 > buf_end)
186 return DEBUG_LOC_BUFFER_OVERFLOW;
188 *high += extract_unsigned_integer (loc_ptr, 4, byte_order);
189 *new_ptr = loc_ptr + 4;
190 return DEBUG_LOC_START_LENGTH;
192 return DEBUG_LOC_INVALID_ENTRY;
196 /* A function for dealing with location lists. Given a
197 symbol baton (BATON) and a pc value (PC), find the appropriate
198 location expression, set *LOCEXPR_LENGTH, and return a pointer
199 to the beginning of the expression. Returns NULL on failure.
201 For now, only return the first matching location expression; there
202 can be more than one in the list. */
205 dwarf2_find_location_expression (struct dwarf2_loclist_baton *baton,
206 size_t *locexpr_length, CORE_ADDR pc)
208 struct objfile *objfile = dwarf2_per_cu_objfile (baton->per_cu);
209 struct gdbarch *gdbarch = get_objfile_arch (objfile);
210 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
211 unsigned int addr_size = dwarf2_per_cu_addr_size (baton->per_cu);
212 int signed_addr_p = bfd_get_sign_extend_vma (objfile->obfd);
213 /* Adjust base_address for relocatable objects. */
214 CORE_ADDR base_offset = dwarf2_per_cu_text_offset (baton->per_cu);
215 CORE_ADDR base_address = baton->base_address + base_offset;
216 const gdb_byte *loc_ptr, *buf_end;
218 loc_ptr = baton->data;
219 buf_end = baton->data + baton->size;
223 CORE_ADDR low = 0, high = 0; /* init for gcc -Wall */
225 enum debug_loc_kind kind;
226 const gdb_byte *new_ptr = NULL; /* init for gcc -Wall */
229 kind = decode_debug_loc_dwo_addresses (baton->per_cu,
230 loc_ptr, buf_end, &new_ptr,
231 &low, &high, byte_order);
233 kind = decode_debug_loc_addresses (loc_ptr, buf_end, &new_ptr,
235 byte_order, addr_size,
240 case DEBUG_LOC_END_OF_LIST:
243 case DEBUG_LOC_BASE_ADDRESS:
244 base_address = high + base_offset;
246 case DEBUG_LOC_START_END:
247 case DEBUG_LOC_START_LENGTH:
249 case DEBUG_LOC_BUFFER_OVERFLOW:
250 case DEBUG_LOC_INVALID_ENTRY:
251 error (_("dwarf2_find_location_expression: "
252 "Corrupted DWARF expression."));
254 gdb_assert_not_reached ("bad debug_loc_kind");
257 /* Otherwise, a location expression entry.
258 If the entry is from a DWO, don't add base address: the entry is
259 from .debug_addr which has absolute addresses. */
260 if (! baton->from_dwo)
263 high += base_address;
266 length = extract_unsigned_integer (loc_ptr, 2, byte_order);
269 if (low == high && pc == low)
271 /* This is entry PC record present only at entry point
272 of a function. Verify it is really the function entry point. */
274 const struct block *pc_block = block_for_pc (pc);
275 struct symbol *pc_func = NULL;
278 pc_func = block_linkage_function (pc_block);
280 if (pc_func && pc == BLOCK_START (SYMBOL_BLOCK_VALUE (pc_func)))
282 *locexpr_length = length;
287 if (pc >= low && pc < high)
289 *locexpr_length = length;
297 /* This is the baton used when performing dwarf2 expression
299 struct dwarf_expr_baton
301 struct frame_info *frame;
302 struct dwarf2_per_cu_data *per_cu;
303 CORE_ADDR obj_address;
306 /* Helper functions for dwarf2_evaluate_loc_desc. */
308 /* Using the frame specified in BATON, return the value of register
309 REGNUM, treated as a pointer. */
311 dwarf_expr_read_addr_from_reg (void *baton, int dwarf_regnum)
313 struct dwarf_expr_baton *debaton = (struct dwarf_expr_baton *) baton;
314 struct gdbarch *gdbarch = get_frame_arch (debaton->frame);
315 int regnum = gdbarch_dwarf2_reg_to_regnum (gdbarch, dwarf_regnum);
317 return address_from_register (regnum, debaton->frame);
320 /* Implement struct dwarf_expr_context_funcs' "get_reg_value" callback. */
322 static struct value *
323 dwarf_expr_get_reg_value (void *baton, struct type *type, int dwarf_regnum)
325 struct dwarf_expr_baton *debaton = (struct dwarf_expr_baton *) baton;
326 struct gdbarch *gdbarch = get_frame_arch (debaton->frame);
327 int regnum = gdbarch_dwarf2_reg_to_regnum (gdbarch, dwarf_regnum);
329 return value_from_register (type, regnum, debaton->frame);
332 /* Read memory at ADDR (length LEN) into BUF. */
335 dwarf_expr_read_mem (void *baton, gdb_byte *buf, CORE_ADDR addr, size_t len)
337 read_memory (addr, buf, len);
340 /* Using the frame specified in BATON, find the location expression
341 describing the frame base. Return a pointer to it in START and
342 its length in LENGTH. */
344 dwarf_expr_frame_base (void *baton, const gdb_byte **start, size_t * length)
346 /* FIXME: cagney/2003-03-26: This code should be using
347 get_frame_base_address(), and then implement a dwarf2 specific
349 struct symbol *framefunc;
350 struct dwarf_expr_baton *debaton = (struct dwarf_expr_baton *) baton;
351 const struct block *bl = get_frame_block (debaton->frame, NULL);
354 error (_("frame address is not available."));
356 /* Use block_linkage_function, which returns a real (not inlined)
357 function, instead of get_frame_function, which may return an
359 framefunc = block_linkage_function (bl);
361 /* If we found a frame-relative symbol then it was certainly within
362 some function associated with a frame. If we can't find the frame,
363 something has gone wrong. */
364 gdb_assert (framefunc != NULL);
366 func_get_frame_base_dwarf_block (framefunc,
367 get_frame_address_in_block (debaton->frame),
371 /* Implement find_frame_base_location method for LOC_BLOCK functions using
372 DWARF expression for its DW_AT_frame_base. */
375 locexpr_find_frame_base_location (struct symbol *framefunc, CORE_ADDR pc,
376 const gdb_byte **start, size_t *length)
378 struct dwarf2_locexpr_baton *symbaton = SYMBOL_LOCATION_BATON (framefunc);
380 *length = symbaton->size;
381 *start = symbaton->data;
384 /* Vector for inferior functions as represented by LOC_BLOCK, if the inferior
385 function uses DWARF expression for its DW_AT_frame_base. */
387 const struct symbol_block_ops dwarf2_block_frame_base_locexpr_funcs =
389 locexpr_find_frame_base_location
392 /* Implement find_frame_base_location method for LOC_BLOCK functions using
393 DWARF location list for its DW_AT_frame_base. */
396 loclist_find_frame_base_location (struct symbol *framefunc, CORE_ADDR pc,
397 const gdb_byte **start, size_t *length)
399 struct dwarf2_loclist_baton *symbaton = SYMBOL_LOCATION_BATON (framefunc);
401 *start = dwarf2_find_location_expression (symbaton, length, pc);
404 /* Vector for inferior functions as represented by LOC_BLOCK, if the inferior
405 function uses DWARF location list for its DW_AT_frame_base. */
407 const struct symbol_block_ops dwarf2_block_frame_base_loclist_funcs =
409 loclist_find_frame_base_location
412 /* See dwarf2loc.h. */
415 func_get_frame_base_dwarf_block (struct symbol *framefunc, CORE_ADDR pc,
416 const gdb_byte **start, size_t *length)
418 if (SYMBOL_BLOCK_OPS (framefunc) != NULL)
420 const struct symbol_block_ops *ops_block = SYMBOL_BLOCK_OPS (framefunc);
422 ops_block->find_frame_base_location (framefunc, pc, start, length);
428 error (_("Could not find the frame base for \"%s\"."),
429 SYMBOL_NATURAL_NAME (framefunc));
432 /* Helper function for dwarf2_evaluate_loc_desc. Computes the CFA for
433 the frame in BATON. */
436 dwarf_expr_frame_cfa (void *baton)
438 struct dwarf_expr_baton *debaton = (struct dwarf_expr_baton *) baton;
440 return dwarf2_frame_cfa (debaton->frame);
443 /* Helper function for dwarf2_evaluate_loc_desc. Computes the PC for
444 the frame in BATON. */
447 dwarf_expr_frame_pc (void *baton)
449 struct dwarf_expr_baton *debaton = (struct dwarf_expr_baton *) baton;
451 return get_frame_address_in_block (debaton->frame);
454 /* Using the objfile specified in BATON, find the address for the
455 current thread's thread-local storage with offset OFFSET. */
457 dwarf_expr_tls_address (void *baton, CORE_ADDR offset)
459 struct dwarf_expr_baton *debaton = (struct dwarf_expr_baton *) baton;
460 struct objfile *objfile = dwarf2_per_cu_objfile (debaton->per_cu);
462 return target_translate_tls_address (objfile, offset);
465 /* Call DWARF subroutine from DW_AT_location of DIE at DIE_OFFSET in
466 current CU (as is PER_CU). State of the CTX is not affected by the
470 per_cu_dwarf_call (struct dwarf_expr_context *ctx, cu_offset die_offset,
471 struct dwarf2_per_cu_data *per_cu,
472 CORE_ADDR (*get_frame_pc) (void *baton),
475 struct dwarf2_locexpr_baton block;
477 block = dwarf2_fetch_die_loc_cu_off (die_offset, per_cu, get_frame_pc, baton);
479 /* DW_OP_call_ref is currently not supported. */
480 gdb_assert (block.per_cu == per_cu);
482 dwarf_expr_eval (ctx, block.data, block.size);
485 /* Helper interface of per_cu_dwarf_call for dwarf2_evaluate_loc_desc. */
488 dwarf_expr_dwarf_call (struct dwarf_expr_context *ctx, cu_offset die_offset)
490 struct dwarf_expr_baton *debaton = ctx->baton;
492 per_cu_dwarf_call (ctx, die_offset, debaton->per_cu,
493 ctx->funcs->get_frame_pc, ctx->baton);
496 /* Callback function for dwarf2_evaluate_loc_desc. */
499 dwarf_expr_get_base_type (struct dwarf_expr_context *ctx,
500 cu_offset die_offset)
502 struct dwarf_expr_baton *debaton = ctx->baton;
504 return dwarf2_get_die_type (die_offset, debaton->per_cu);
507 /* See dwarf2loc.h. */
509 unsigned int entry_values_debug = 0;
511 /* Helper to set entry_values_debug. */
514 show_entry_values_debug (struct ui_file *file, int from_tty,
515 struct cmd_list_element *c, const char *value)
517 fprintf_filtered (file,
518 _("Entry values and tail call frames debugging is %s.\n"),
522 /* Find DW_TAG_GNU_call_site's DW_AT_GNU_call_site_target address.
523 CALLER_FRAME (for registers) can be NULL if it is not known. This function
524 always returns valid address or it throws NO_ENTRY_VALUE_ERROR. */
527 call_site_to_target_addr (struct gdbarch *call_site_gdbarch,
528 struct call_site *call_site,
529 struct frame_info *caller_frame)
531 switch (FIELD_LOC_KIND (call_site->target))
533 case FIELD_LOC_KIND_DWARF_BLOCK:
535 struct dwarf2_locexpr_baton *dwarf_block;
537 struct type *caller_core_addr_type;
538 struct gdbarch *caller_arch;
540 dwarf_block = FIELD_DWARF_BLOCK (call_site->target);
541 if (dwarf_block == NULL)
543 struct bound_minimal_symbol msym;
545 msym = lookup_minimal_symbol_by_pc (call_site->pc - 1);
546 throw_error (NO_ENTRY_VALUE_ERROR,
547 _("DW_AT_GNU_call_site_target is not specified "
549 paddress (call_site_gdbarch, call_site->pc),
550 (msym.minsym == NULL ? "???"
551 : MSYMBOL_PRINT_NAME (msym.minsym)));
554 if (caller_frame == NULL)
556 struct bound_minimal_symbol msym;
558 msym = lookup_minimal_symbol_by_pc (call_site->pc - 1);
559 throw_error (NO_ENTRY_VALUE_ERROR,
560 _("DW_AT_GNU_call_site_target DWARF block resolving "
561 "requires known frame which is currently not "
562 "available at %s in %s"),
563 paddress (call_site_gdbarch, call_site->pc),
564 (msym.minsym == NULL ? "???"
565 : MSYMBOL_PRINT_NAME (msym.minsym)));
568 caller_arch = get_frame_arch (caller_frame);
569 caller_core_addr_type = builtin_type (caller_arch)->builtin_func_ptr;
570 val = dwarf2_evaluate_loc_desc (caller_core_addr_type, caller_frame,
571 dwarf_block->data, dwarf_block->size,
572 dwarf_block->per_cu);
573 /* DW_AT_GNU_call_site_target is a DWARF expression, not a DWARF
575 if (VALUE_LVAL (val) == lval_memory)
576 return value_address (val);
578 return value_as_address (val);
581 case FIELD_LOC_KIND_PHYSNAME:
583 const char *physname;
584 struct bound_minimal_symbol msym;
586 physname = FIELD_STATIC_PHYSNAME (call_site->target);
588 /* Handle both the mangled and demangled PHYSNAME. */
589 msym = lookup_minimal_symbol (physname, NULL, NULL);
590 if (msym.minsym == NULL)
592 msym = lookup_minimal_symbol_by_pc (call_site->pc - 1);
593 throw_error (NO_ENTRY_VALUE_ERROR,
594 _("Cannot find function \"%s\" for a call site target "
596 physname, paddress (call_site_gdbarch, call_site->pc),
597 (msym.minsym == NULL ? "???"
598 : MSYMBOL_PRINT_NAME (msym.minsym)));
601 return BMSYMBOL_VALUE_ADDRESS (msym);
604 case FIELD_LOC_KIND_PHYSADDR:
605 return FIELD_STATIC_PHYSADDR (call_site->target);
608 internal_error (__FILE__, __LINE__, _("invalid call site target kind"));
612 /* Convert function entry point exact address ADDR to the function which is
613 compliant with TAIL_CALL_LIST_COMPLETE condition. Throw
614 NO_ENTRY_VALUE_ERROR otherwise. */
616 static struct symbol *
617 func_addr_to_tail_call_list (struct gdbarch *gdbarch, CORE_ADDR addr)
619 struct symbol *sym = find_pc_function (addr);
622 if (sym == NULL || BLOCK_START (SYMBOL_BLOCK_VALUE (sym)) != addr)
623 throw_error (NO_ENTRY_VALUE_ERROR,
624 _("DW_TAG_GNU_call_site resolving failed to find function "
625 "name for address %s"),
626 paddress (gdbarch, addr));
628 type = SYMBOL_TYPE (sym);
629 gdb_assert (TYPE_CODE (type) == TYPE_CODE_FUNC);
630 gdb_assert (TYPE_SPECIFIC_FIELD (type) == TYPE_SPECIFIC_FUNC);
635 /* Verify function with entry point exact address ADDR can never call itself
636 via its tail calls (incl. transitively). Throw NO_ENTRY_VALUE_ERROR if it
637 can call itself via tail calls.
639 If a funtion can tail call itself its entry value based parameters are
640 unreliable. There is no verification whether the value of some/all
641 parameters is unchanged through the self tail call, we expect if there is
642 a self tail call all the parameters can be modified. */
645 func_verify_no_selftailcall (struct gdbarch *gdbarch, CORE_ADDR verify_addr)
647 struct obstack addr_obstack;
648 struct cleanup *old_chain;
651 /* Track here CORE_ADDRs which were already visited. */
654 /* The verification is completely unordered. Track here function addresses
655 which still need to be iterated. */
656 VEC (CORE_ADDR) *todo = NULL;
658 obstack_init (&addr_obstack);
659 old_chain = make_cleanup_obstack_free (&addr_obstack);
660 addr_hash = htab_create_alloc_ex (64, core_addr_hash, core_addr_eq, NULL,
661 &addr_obstack, hashtab_obstack_allocate,
663 make_cleanup_htab_delete (addr_hash);
665 make_cleanup (VEC_cleanup (CORE_ADDR), &todo);
667 VEC_safe_push (CORE_ADDR, todo, verify_addr);
668 while (!VEC_empty (CORE_ADDR, todo))
670 struct symbol *func_sym;
671 struct call_site *call_site;
673 addr = VEC_pop (CORE_ADDR, todo);
675 func_sym = func_addr_to_tail_call_list (gdbarch, addr);
677 for (call_site = TYPE_TAIL_CALL_LIST (SYMBOL_TYPE (func_sym));
678 call_site; call_site = call_site->tail_call_next)
680 CORE_ADDR target_addr;
683 /* CALLER_FRAME with registers is not available for tail-call jumped
685 target_addr = call_site_to_target_addr (gdbarch, call_site, NULL);
687 if (target_addr == verify_addr)
689 struct bound_minimal_symbol msym;
691 msym = lookup_minimal_symbol_by_pc (verify_addr);
692 throw_error (NO_ENTRY_VALUE_ERROR,
693 _("DW_OP_GNU_entry_value resolving has found "
694 "function \"%s\" at %s can call itself via tail "
696 (msym.minsym == NULL ? "???"
697 : MSYMBOL_PRINT_NAME (msym.minsym)),
698 paddress (gdbarch, verify_addr));
701 slot = htab_find_slot (addr_hash, &target_addr, INSERT);
704 *slot = obstack_copy (&addr_obstack, &target_addr,
705 sizeof (target_addr));
706 VEC_safe_push (CORE_ADDR, todo, target_addr);
711 do_cleanups (old_chain);
714 /* Print user readable form of CALL_SITE->PC to gdb_stdlog. Used only for
715 ENTRY_VALUES_DEBUG. */
718 tailcall_dump (struct gdbarch *gdbarch, const struct call_site *call_site)
720 CORE_ADDR addr = call_site->pc;
721 struct bound_minimal_symbol msym = lookup_minimal_symbol_by_pc (addr - 1);
723 fprintf_unfiltered (gdb_stdlog, " %s(%s)", paddress (gdbarch, addr),
724 (msym.minsym == NULL ? "???"
725 : MSYMBOL_PRINT_NAME (msym.minsym)));
729 /* vec.h needs single word type name, typedef it. */
730 typedef struct call_site *call_sitep;
732 /* Define VEC (call_sitep) functions. */
733 DEF_VEC_P (call_sitep);
735 /* Intersect RESULTP with CHAIN to keep RESULTP unambiguous, keep in RESULTP
736 only top callers and bottom callees which are present in both. GDBARCH is
737 used only for ENTRY_VALUES_DEBUG. RESULTP is NULL after return if there are
738 no remaining possibilities to provide unambiguous non-trivial result.
739 RESULTP should point to NULL on the first (initialization) call. Caller is
740 responsible for xfree of any RESULTP data. */
743 chain_candidate (struct gdbarch *gdbarch, struct call_site_chain **resultp,
744 VEC (call_sitep) *chain)
746 struct call_site_chain *result = *resultp;
747 long length = VEC_length (call_sitep, chain);
748 int callers, callees, idx;
752 /* Create the initial chain containing all the passed PCs. */
754 result = xmalloc (sizeof (*result) + sizeof (*result->call_site)
756 result->length = length;
757 result->callers = result->callees = length;
758 if (!VEC_empty (call_sitep, chain))
759 memcpy (result->call_site, VEC_address (call_sitep, chain),
760 sizeof (*result->call_site) * length);
763 if (entry_values_debug)
765 fprintf_unfiltered (gdb_stdlog, "tailcall: initial:");
766 for (idx = 0; idx < length; idx++)
767 tailcall_dump (gdbarch, result->call_site[idx]);
768 fputc_unfiltered ('\n', gdb_stdlog);
774 if (entry_values_debug)
776 fprintf_unfiltered (gdb_stdlog, "tailcall: compare:");
777 for (idx = 0; idx < length; idx++)
778 tailcall_dump (gdbarch, VEC_index (call_sitep, chain, idx));
779 fputc_unfiltered ('\n', gdb_stdlog);
782 /* Intersect callers. */
784 callers = min (result->callers, length);
785 for (idx = 0; idx < callers; idx++)
786 if (result->call_site[idx] != VEC_index (call_sitep, chain, idx))
788 result->callers = idx;
792 /* Intersect callees. */
794 callees = min (result->callees, length);
795 for (idx = 0; idx < callees; idx++)
796 if (result->call_site[result->length - 1 - idx]
797 != VEC_index (call_sitep, chain, length - 1 - idx))
799 result->callees = idx;
803 if (entry_values_debug)
805 fprintf_unfiltered (gdb_stdlog, "tailcall: reduced:");
806 for (idx = 0; idx < result->callers; idx++)
807 tailcall_dump (gdbarch, result->call_site[idx]);
808 fputs_unfiltered (" |", gdb_stdlog);
809 for (idx = 0; idx < result->callees; idx++)
810 tailcall_dump (gdbarch, result->call_site[result->length
811 - result->callees + idx]);
812 fputc_unfiltered ('\n', gdb_stdlog);
815 if (result->callers == 0 && result->callees == 0)
817 /* There are no common callers or callees. It could be also a direct
818 call (which has length 0) with ambiguous possibility of an indirect
819 call - CALLERS == CALLEES == 0 is valid during the first allocation
820 but any subsequence processing of such entry means ambiguity. */
826 /* See call_site_find_chain_1 why there is no way to reach the bottom callee
827 PC again. In such case there must be two different code paths to reach
828 it, therefore some of the former determined intermediate PCs must differ
829 and the unambiguous chain gets shortened. */
830 gdb_assert (result->callers + result->callees < result->length);
833 /* Create and return call_site_chain for CALLER_PC and CALLEE_PC. All the
834 assumed frames between them use GDBARCH. Use depth first search so we can
835 keep single CHAIN of call_site's back to CALLER_PC. Function recursion
836 would have needless GDB stack overhead. Caller is responsible for xfree of
837 the returned result. Any unreliability results in thrown
838 NO_ENTRY_VALUE_ERROR. */
840 static struct call_site_chain *
841 call_site_find_chain_1 (struct gdbarch *gdbarch, CORE_ADDR caller_pc,
844 CORE_ADDR save_callee_pc = callee_pc;
845 struct obstack addr_obstack;
846 struct cleanup *back_to_retval, *back_to_workdata;
847 struct call_site_chain *retval = NULL;
848 struct call_site *call_site;
850 /* Mark CALL_SITEs so we do not visit the same ones twice. */
853 /* CHAIN contains only the intermediate CALL_SITEs. Neither CALLER_PC's
854 call_site nor any possible call_site at CALLEE_PC's function is there.
855 Any CALL_SITE in CHAIN will be iterated to its siblings - via
856 TAIL_CALL_NEXT. This is inappropriate for CALLER_PC's call_site. */
857 VEC (call_sitep) *chain = NULL;
859 /* We are not interested in the specific PC inside the callee function. */
860 callee_pc = get_pc_function_start (callee_pc);
862 throw_error (NO_ENTRY_VALUE_ERROR, _("Unable to find function for PC %s"),
863 paddress (gdbarch, save_callee_pc));
865 back_to_retval = make_cleanup (free_current_contents, &retval);
867 obstack_init (&addr_obstack);
868 back_to_workdata = make_cleanup_obstack_free (&addr_obstack);
869 addr_hash = htab_create_alloc_ex (64, core_addr_hash, core_addr_eq, NULL,
870 &addr_obstack, hashtab_obstack_allocate,
872 make_cleanup_htab_delete (addr_hash);
874 make_cleanup (VEC_cleanup (call_sitep), &chain);
876 /* Do not push CALL_SITE to CHAIN. Push there only the first tail call site
877 at the target's function. All the possible tail call sites in the
878 target's function will get iterated as already pushed into CHAIN via their
880 call_site = call_site_for_pc (gdbarch, caller_pc);
884 CORE_ADDR target_func_addr;
885 struct call_site *target_call_site;
887 /* CALLER_FRAME with registers is not available for tail-call jumped
889 target_func_addr = call_site_to_target_addr (gdbarch, call_site, NULL);
891 if (target_func_addr == callee_pc)
893 chain_candidate (gdbarch, &retval, chain);
897 /* There is no way to reach CALLEE_PC again as we would prevent
898 entering it twice as being already marked in ADDR_HASH. */
899 target_call_site = NULL;
903 struct symbol *target_func;
905 target_func = func_addr_to_tail_call_list (gdbarch, target_func_addr);
906 target_call_site = TYPE_TAIL_CALL_LIST (SYMBOL_TYPE (target_func));
911 /* Attempt to visit TARGET_CALL_SITE. */
913 if (target_call_site)
917 slot = htab_find_slot (addr_hash, &target_call_site->pc, INSERT);
920 /* Successfully entered TARGET_CALL_SITE. */
922 *slot = &target_call_site->pc;
923 VEC_safe_push (call_sitep, chain, target_call_site);
928 /* Backtrack (without revisiting the originating call_site). Try the
929 callers's sibling; if there isn't any try the callers's callers's
932 target_call_site = NULL;
933 while (!VEC_empty (call_sitep, chain))
935 call_site = VEC_pop (call_sitep, chain);
937 gdb_assert (htab_find_slot (addr_hash, &call_site->pc,
939 htab_remove_elt (addr_hash, &call_site->pc);
941 target_call_site = call_site->tail_call_next;
942 if (target_call_site)
946 while (target_call_site);
948 if (VEC_empty (call_sitep, chain))
951 call_site = VEC_last (call_sitep, chain);
956 struct bound_minimal_symbol msym_caller, msym_callee;
958 msym_caller = lookup_minimal_symbol_by_pc (caller_pc);
959 msym_callee = lookup_minimal_symbol_by_pc (callee_pc);
960 throw_error (NO_ENTRY_VALUE_ERROR,
961 _("There are no unambiguously determinable intermediate "
962 "callers or callees between caller function \"%s\" at %s "
963 "and callee function \"%s\" at %s"),
964 (msym_caller.minsym == NULL
965 ? "???" : MSYMBOL_PRINT_NAME (msym_caller.minsym)),
966 paddress (gdbarch, caller_pc),
967 (msym_callee.minsym == NULL
968 ? "???" : MSYMBOL_PRINT_NAME (msym_callee.minsym)),
969 paddress (gdbarch, callee_pc));
972 do_cleanups (back_to_workdata);
973 discard_cleanups (back_to_retval);
977 /* Create and return call_site_chain for CALLER_PC and CALLEE_PC. All the
978 assumed frames between them use GDBARCH. If valid call_site_chain cannot be
979 constructed return NULL. Caller is responsible for xfree of the returned
982 struct call_site_chain *
983 call_site_find_chain (struct gdbarch *gdbarch, CORE_ADDR caller_pc,
986 volatile struct gdb_exception e;
987 struct call_site_chain *retval = NULL;
989 TRY_CATCH (e, RETURN_MASK_ERROR)
991 retval = call_site_find_chain_1 (gdbarch, caller_pc, callee_pc);
995 if (e.error == NO_ENTRY_VALUE_ERROR)
997 if (entry_values_debug)
998 exception_print (gdb_stdout, e);
1003 throw_exception (e);
1008 /* Return 1 if KIND and KIND_U match PARAMETER. Return 0 otherwise. */
1011 call_site_parameter_matches (struct call_site_parameter *parameter,
1012 enum call_site_parameter_kind kind,
1013 union call_site_parameter_u kind_u)
1015 if (kind == parameter->kind)
1018 case CALL_SITE_PARAMETER_DWARF_REG:
1019 return kind_u.dwarf_reg == parameter->u.dwarf_reg;
1020 case CALL_SITE_PARAMETER_FB_OFFSET:
1021 return kind_u.fb_offset == parameter->u.fb_offset;
1022 case CALL_SITE_PARAMETER_PARAM_OFFSET:
1023 return kind_u.param_offset.cu_off == parameter->u.param_offset.cu_off;
1028 /* Fetch call_site_parameter from caller matching KIND and KIND_U.
1029 FRAME is for callee.
1031 Function always returns non-NULL, it throws NO_ENTRY_VALUE_ERROR
1034 static struct call_site_parameter *
1035 dwarf_expr_reg_to_entry_parameter (struct frame_info *frame,
1036 enum call_site_parameter_kind kind,
1037 union call_site_parameter_u kind_u,
1038 struct dwarf2_per_cu_data **per_cu_return)
1040 CORE_ADDR func_addr, caller_pc;
1041 struct gdbarch *gdbarch;
1042 struct frame_info *caller_frame;
1043 struct call_site *call_site;
1045 /* Initialize it just to avoid a GCC false warning. */
1046 struct call_site_parameter *parameter = NULL;
1047 CORE_ADDR target_addr;
1049 while (get_frame_type (frame) == INLINE_FRAME)
1051 frame = get_prev_frame (frame);
1052 gdb_assert (frame != NULL);
1055 func_addr = get_frame_func (frame);
1056 gdbarch = get_frame_arch (frame);
1057 caller_frame = get_prev_frame (frame);
1058 if (gdbarch != frame_unwind_arch (frame))
1060 struct bound_minimal_symbol msym
1061 = lookup_minimal_symbol_by_pc (func_addr);
1062 struct gdbarch *caller_gdbarch = frame_unwind_arch (frame);
1064 throw_error (NO_ENTRY_VALUE_ERROR,
1065 _("DW_OP_GNU_entry_value resolving callee gdbarch %s "
1066 "(of %s (%s)) does not match caller gdbarch %s"),
1067 gdbarch_bfd_arch_info (gdbarch)->printable_name,
1068 paddress (gdbarch, func_addr),
1069 (msym.minsym == NULL ? "???"
1070 : MSYMBOL_PRINT_NAME (msym.minsym)),
1071 gdbarch_bfd_arch_info (caller_gdbarch)->printable_name);
1074 if (caller_frame == NULL)
1076 struct bound_minimal_symbol msym
1077 = lookup_minimal_symbol_by_pc (func_addr);
1079 throw_error (NO_ENTRY_VALUE_ERROR, _("DW_OP_GNU_entry_value resolving "
1080 "requires caller of %s (%s)"),
1081 paddress (gdbarch, func_addr),
1082 (msym.minsym == NULL ? "???"
1083 : MSYMBOL_PRINT_NAME (msym.minsym)));
1085 caller_pc = get_frame_pc (caller_frame);
1086 call_site = call_site_for_pc (gdbarch, caller_pc);
1088 target_addr = call_site_to_target_addr (gdbarch, call_site, caller_frame);
1089 if (target_addr != func_addr)
1091 struct minimal_symbol *target_msym, *func_msym;
1093 target_msym = lookup_minimal_symbol_by_pc (target_addr).minsym;
1094 func_msym = lookup_minimal_symbol_by_pc (func_addr).minsym;
1095 throw_error (NO_ENTRY_VALUE_ERROR,
1096 _("DW_OP_GNU_entry_value resolving expects callee %s at %s "
1097 "but the called frame is for %s at %s"),
1098 (target_msym == NULL ? "???"
1099 : MSYMBOL_PRINT_NAME (target_msym)),
1100 paddress (gdbarch, target_addr),
1101 func_msym == NULL ? "???" : MSYMBOL_PRINT_NAME (func_msym),
1102 paddress (gdbarch, func_addr));
1105 /* No entry value based parameters would be reliable if this function can
1106 call itself via tail calls. */
1107 func_verify_no_selftailcall (gdbarch, func_addr);
1109 for (iparams = 0; iparams < call_site->parameter_count; iparams++)
1111 parameter = &call_site->parameter[iparams];
1112 if (call_site_parameter_matches (parameter, kind, kind_u))
1115 if (iparams == call_site->parameter_count)
1117 struct minimal_symbol *msym
1118 = lookup_minimal_symbol_by_pc (caller_pc).minsym;
1120 /* DW_TAG_GNU_call_site_parameter will be missing just if GCC could not
1121 determine its value. */
1122 throw_error (NO_ENTRY_VALUE_ERROR, _("Cannot find matching parameter "
1123 "at DW_TAG_GNU_call_site %s at %s"),
1124 paddress (gdbarch, caller_pc),
1125 msym == NULL ? "???" : MSYMBOL_PRINT_NAME (msym));
1128 *per_cu_return = call_site->per_cu;
1132 /* Return value for PARAMETER matching DEREF_SIZE. If DEREF_SIZE is -1, return
1133 the normal DW_AT_GNU_call_site_value block. Otherwise return the
1134 DW_AT_GNU_call_site_data_value (dereferenced) block.
1136 TYPE and CALLER_FRAME specify how to evaluate the DWARF block into returned
1139 Function always returns non-NULL, non-optimized out value. It throws
1140 NO_ENTRY_VALUE_ERROR if it cannot resolve the value for any reason. */
1142 static struct value *
1143 dwarf_entry_parameter_to_value (struct call_site_parameter *parameter,
1144 CORE_ADDR deref_size, struct type *type,
1145 struct frame_info *caller_frame,
1146 struct dwarf2_per_cu_data *per_cu)
1148 const gdb_byte *data_src;
1152 data_src = deref_size == -1 ? parameter->value : parameter->data_value;
1153 size = deref_size == -1 ? parameter->value_size : parameter->data_value_size;
1155 /* DEREF_SIZE size is not verified here. */
1156 if (data_src == NULL)
1157 throw_error (NO_ENTRY_VALUE_ERROR,
1158 _("Cannot resolve DW_AT_GNU_call_site_data_value"));
1160 /* DW_AT_GNU_call_site_value is a DWARF expression, not a DWARF
1161 location. Postprocessing of DWARF_VALUE_MEMORY would lose the type from
1163 data = alloca (size + 1);
1164 memcpy (data, data_src, size);
1165 data[size] = DW_OP_stack_value;
1167 return dwarf2_evaluate_loc_desc (type, caller_frame, data, size + 1, per_cu);
1170 /* Execute DWARF block of call_site_parameter which matches KIND and KIND_U.
1171 Choose DEREF_SIZE value of that parameter. Search caller of the CTX's
1172 frame. CTX must be of dwarf_expr_ctx_funcs kind.
1174 The CTX caller can be from a different CU - per_cu_dwarf_call implementation
1175 can be more simple as it does not support cross-CU DWARF executions. */
1178 dwarf_expr_push_dwarf_reg_entry_value (struct dwarf_expr_context *ctx,
1179 enum call_site_parameter_kind kind,
1180 union call_site_parameter_u kind_u,
1183 struct dwarf_expr_baton *debaton;
1184 struct frame_info *frame, *caller_frame;
1185 struct dwarf2_per_cu_data *caller_per_cu;
1186 struct dwarf_expr_baton baton_local;
1187 struct dwarf_expr_context saved_ctx;
1188 struct call_site_parameter *parameter;
1189 const gdb_byte *data_src;
1192 gdb_assert (ctx->funcs == &dwarf_expr_ctx_funcs);
1193 debaton = ctx->baton;
1194 frame = debaton->frame;
1195 caller_frame = get_prev_frame (frame);
1197 parameter = dwarf_expr_reg_to_entry_parameter (frame, kind, kind_u,
1199 data_src = deref_size == -1 ? parameter->value : parameter->data_value;
1200 size = deref_size == -1 ? parameter->value_size : parameter->data_value_size;
1202 /* DEREF_SIZE size is not verified here. */
1203 if (data_src == NULL)
1204 throw_error (NO_ENTRY_VALUE_ERROR,
1205 _("Cannot resolve DW_AT_GNU_call_site_data_value"));
1207 baton_local.frame = caller_frame;
1208 baton_local.per_cu = caller_per_cu;
1209 baton_local.obj_address = 0;
1211 saved_ctx.gdbarch = ctx->gdbarch;
1212 saved_ctx.addr_size = ctx->addr_size;
1213 saved_ctx.offset = ctx->offset;
1214 saved_ctx.baton = ctx->baton;
1215 ctx->gdbarch = get_objfile_arch (dwarf2_per_cu_objfile (baton_local.per_cu));
1216 ctx->addr_size = dwarf2_per_cu_addr_size (baton_local.per_cu);
1217 ctx->offset = dwarf2_per_cu_text_offset (baton_local.per_cu);
1218 ctx->baton = &baton_local;
1220 dwarf_expr_eval (ctx, data_src, size);
1222 ctx->gdbarch = saved_ctx.gdbarch;
1223 ctx->addr_size = saved_ctx.addr_size;
1224 ctx->offset = saved_ctx.offset;
1225 ctx->baton = saved_ctx.baton;
1228 /* Callback function for dwarf2_evaluate_loc_desc.
1229 Fetch the address indexed by DW_OP_GNU_addr_index. */
1232 dwarf_expr_get_addr_index (void *baton, unsigned int index)
1234 struct dwarf_expr_baton *debaton = (struct dwarf_expr_baton *) baton;
1236 return dwarf2_read_addr_index (debaton->per_cu, index);
1239 /* Callback function for get_object_address. Return the address of the VLA
1243 dwarf_expr_get_obj_addr (void *baton)
1245 struct dwarf_expr_baton *debaton = baton;
1247 gdb_assert (debaton != NULL);
1249 if (debaton->obj_address == 0)
1250 error (_("Location address is not set."));
1252 return debaton->obj_address;
1255 /* VALUE must be of type lval_computed with entry_data_value_funcs. Perform
1256 the indirect method on it, that is use its stored target value, the sole
1257 purpose of entry_data_value_funcs.. */
1259 static struct value *
1260 entry_data_value_coerce_ref (const struct value *value)
1262 struct type *checked_type = check_typedef (value_type (value));
1263 struct value *target_val;
1265 if (TYPE_CODE (checked_type) != TYPE_CODE_REF)
1268 target_val = value_computed_closure (value);
1269 value_incref (target_val);
1273 /* Implement copy_closure. */
1276 entry_data_value_copy_closure (const struct value *v)
1278 struct value *target_val = value_computed_closure (v);
1280 value_incref (target_val);
1284 /* Implement free_closure. */
1287 entry_data_value_free_closure (struct value *v)
1289 struct value *target_val = value_computed_closure (v);
1291 value_free (target_val);
1294 /* Vector for methods for an entry value reference where the referenced value
1295 is stored in the caller. On the first dereference use
1296 DW_AT_GNU_call_site_data_value in the caller. */
1298 static const struct lval_funcs entry_data_value_funcs =
1302 NULL, /* indirect */
1303 entry_data_value_coerce_ref,
1304 NULL, /* check_synthetic_pointer */
1305 entry_data_value_copy_closure,
1306 entry_data_value_free_closure
1309 /* Read parameter of TYPE at (callee) FRAME's function entry. KIND and KIND_U
1310 are used to match DW_AT_location at the caller's
1311 DW_TAG_GNU_call_site_parameter.
1313 Function always returns non-NULL value. It throws NO_ENTRY_VALUE_ERROR if it
1314 cannot resolve the parameter for any reason. */
1316 static struct value *
1317 value_of_dwarf_reg_entry (struct type *type, struct frame_info *frame,
1318 enum call_site_parameter_kind kind,
1319 union call_site_parameter_u kind_u)
1321 struct type *checked_type = check_typedef (type);
1322 struct type *target_type = TYPE_TARGET_TYPE (checked_type);
1323 struct frame_info *caller_frame = get_prev_frame (frame);
1324 struct value *outer_val, *target_val, *val;
1325 struct call_site_parameter *parameter;
1326 struct dwarf2_per_cu_data *caller_per_cu;
1328 parameter = dwarf_expr_reg_to_entry_parameter (frame, kind, kind_u,
1331 outer_val = dwarf_entry_parameter_to_value (parameter, -1 /* deref_size */,
1335 /* Check if DW_AT_GNU_call_site_data_value cannot be used. If it should be
1336 used and it is not available do not fall back to OUTER_VAL - dereferencing
1337 TYPE_CODE_REF with non-entry data value would give current value - not the
1340 if (TYPE_CODE (checked_type) != TYPE_CODE_REF
1341 || TYPE_TARGET_TYPE (checked_type) == NULL)
1344 target_val = dwarf_entry_parameter_to_value (parameter,
1345 TYPE_LENGTH (target_type),
1346 target_type, caller_frame,
1349 release_value (target_val);
1350 val = allocate_computed_value (type, &entry_data_value_funcs,
1351 target_val /* closure */);
1353 /* Copy the referencing pointer to the new computed value. */
1354 memcpy (value_contents_raw (val), value_contents_raw (outer_val),
1355 TYPE_LENGTH (checked_type));
1356 set_value_lazy (val, 0);
1361 /* Read parameter of TYPE at (callee) FRAME's function entry. DATA and
1362 SIZE are DWARF block used to match DW_AT_location at the caller's
1363 DW_TAG_GNU_call_site_parameter.
1365 Function always returns non-NULL value. It throws NO_ENTRY_VALUE_ERROR if it
1366 cannot resolve the parameter for any reason. */
1368 static struct value *
1369 value_of_dwarf_block_entry (struct type *type, struct frame_info *frame,
1370 const gdb_byte *block, size_t block_len)
1372 union call_site_parameter_u kind_u;
1374 kind_u.dwarf_reg = dwarf_block_to_dwarf_reg (block, block + block_len);
1375 if (kind_u.dwarf_reg != -1)
1376 return value_of_dwarf_reg_entry (type, frame, CALL_SITE_PARAMETER_DWARF_REG,
1379 if (dwarf_block_to_fb_offset (block, block + block_len, &kind_u.fb_offset))
1380 return value_of_dwarf_reg_entry (type, frame, CALL_SITE_PARAMETER_FB_OFFSET,
1383 /* This can normally happen - throw NO_ENTRY_VALUE_ERROR to get the message
1384 suppressed during normal operation. The expression can be arbitrary if
1385 there is no caller-callee entry value binding expected. */
1386 throw_error (NO_ENTRY_VALUE_ERROR,
1387 _("DWARF-2 expression error: DW_OP_GNU_entry_value is supported "
1388 "only for single DW_OP_reg* or for DW_OP_fbreg(*)"));
1391 struct piece_closure
1393 /* Reference count. */
1396 /* The CU from which this closure's expression came. */
1397 struct dwarf2_per_cu_data *per_cu;
1399 /* The number of pieces used to describe this variable. */
1402 /* The target address size, used only for DWARF_VALUE_STACK. */
1405 /* The pieces themselves. */
1406 struct dwarf_expr_piece *pieces;
1409 /* Allocate a closure for a value formed from separately-described
1412 static struct piece_closure *
1413 allocate_piece_closure (struct dwarf2_per_cu_data *per_cu,
1414 int n_pieces, struct dwarf_expr_piece *pieces,
1417 struct piece_closure *c = XCNEW (struct piece_closure);
1422 c->n_pieces = n_pieces;
1423 c->addr_size = addr_size;
1424 c->pieces = XCNEWVEC (struct dwarf_expr_piece, n_pieces);
1426 memcpy (c->pieces, pieces, n_pieces * sizeof (struct dwarf_expr_piece));
1427 for (i = 0; i < n_pieces; ++i)
1428 if (c->pieces[i].location == DWARF_VALUE_STACK)
1429 value_incref (c->pieces[i].v.value);
1434 /* The lowest-level function to extract bits from a byte buffer.
1435 SOURCE is the buffer. It is updated if we read to the end of a
1437 SOURCE_OFFSET_BITS is the offset of the first bit to read. It is
1438 updated to reflect the number of bits actually read.
1439 NBITS is the number of bits we want to read. It is updated to
1440 reflect the number of bits actually read. This function may read
1442 BITS_BIG_ENDIAN is taken directly from gdbarch.
1443 This function returns the extracted bits. */
1446 extract_bits_primitive (const gdb_byte **source,
1447 unsigned int *source_offset_bits,
1448 int *nbits, int bits_big_endian)
1450 unsigned int avail, mask, datum;
1452 gdb_assert (*source_offset_bits < 8);
1454 avail = 8 - *source_offset_bits;
1458 mask = (1 << avail) - 1;
1460 if (bits_big_endian)
1461 datum >>= 8 - (*source_offset_bits + *nbits);
1463 datum >>= *source_offset_bits;
1467 *source_offset_bits += avail;
1468 if (*source_offset_bits >= 8)
1470 *source_offset_bits -= 8;
1477 /* Extract some bits from a source buffer and move forward in the
1480 SOURCE is the source buffer. It is updated as bytes are read.
1481 SOURCE_OFFSET_BITS is the offset into SOURCE. It is updated as
1483 NBITS is the number of bits to read.
1484 BITS_BIG_ENDIAN is taken directly from gdbarch.
1486 This function returns the bits that were read. */
1489 extract_bits (const gdb_byte **source, unsigned int *source_offset_bits,
1490 int nbits, int bits_big_endian)
1494 gdb_assert (nbits > 0 && nbits <= 8);
1496 datum = extract_bits_primitive (source, source_offset_bits, &nbits,
1502 more = extract_bits_primitive (source, source_offset_bits, &nbits,
1504 if (bits_big_endian)
1514 /* Write some bits into a buffer and move forward in the buffer.
1516 DATUM is the bits to write. The low-order bits of DATUM are used.
1517 DEST is the destination buffer. It is updated as bytes are
1519 DEST_OFFSET_BITS is the bit offset in DEST at which writing is
1521 NBITS is the number of valid bits in DATUM.
1522 BITS_BIG_ENDIAN is taken directly from gdbarch. */
1525 insert_bits (unsigned int datum,
1526 gdb_byte *dest, unsigned int dest_offset_bits,
1527 int nbits, int bits_big_endian)
1531 gdb_assert (dest_offset_bits + nbits <= 8);
1533 mask = (1 << nbits) - 1;
1534 if (bits_big_endian)
1536 datum <<= 8 - (dest_offset_bits + nbits);
1537 mask <<= 8 - (dest_offset_bits + nbits);
1541 datum <<= dest_offset_bits;
1542 mask <<= dest_offset_bits;
1545 gdb_assert ((datum & ~mask) == 0);
1547 *dest = (*dest & ~mask) | datum;
1550 /* Copy bits from a source to a destination.
1552 DEST is where the bits should be written.
1553 DEST_OFFSET_BITS is the bit offset into DEST.
1554 SOURCE is the source of bits.
1555 SOURCE_OFFSET_BITS is the bit offset into SOURCE.
1556 BIT_COUNT is the number of bits to copy.
1557 BITS_BIG_ENDIAN is taken directly from gdbarch. */
1560 copy_bitwise (gdb_byte *dest, unsigned int dest_offset_bits,
1561 const gdb_byte *source, unsigned int source_offset_bits,
1562 unsigned int bit_count,
1563 int bits_big_endian)
1565 unsigned int dest_avail;
1568 /* Reduce everything to byte-size pieces. */
1569 dest += dest_offset_bits / 8;
1570 dest_offset_bits %= 8;
1571 source += source_offset_bits / 8;
1572 source_offset_bits %= 8;
1574 dest_avail = 8 - dest_offset_bits % 8;
1576 /* See if we can fill the first destination byte. */
1577 if (dest_avail < bit_count)
1579 datum = extract_bits (&source, &source_offset_bits, dest_avail,
1581 insert_bits (datum, dest, dest_offset_bits, dest_avail, bits_big_endian);
1583 dest_offset_bits = 0;
1584 bit_count -= dest_avail;
1587 /* Now, either DEST_OFFSET_BITS is byte-aligned, or we have fewer
1588 than 8 bits remaining. */
1589 gdb_assert (dest_offset_bits % 8 == 0 || bit_count < 8);
1590 for (; bit_count >= 8; bit_count -= 8)
1592 datum = extract_bits (&source, &source_offset_bits, 8, bits_big_endian);
1593 *dest++ = (gdb_byte) datum;
1596 /* Finally, we may have a few leftover bits. */
1597 gdb_assert (bit_count <= 8 - dest_offset_bits % 8);
1600 datum = extract_bits (&source, &source_offset_bits, bit_count,
1602 insert_bits (datum, dest, dest_offset_bits, bit_count, bits_big_endian);
1607 read_pieced_value (struct value *v)
1611 ULONGEST bits_to_skip;
1613 struct piece_closure *c
1614 = (struct piece_closure *) value_computed_closure (v);
1615 struct frame_info *frame = frame_find_by_id (VALUE_FRAME_ID (v));
1617 size_t buffer_size = 0;
1618 gdb_byte *buffer = NULL;
1619 struct cleanup *cleanup;
1621 = gdbarch_bits_big_endian (get_type_arch (value_type (v)));
1623 if (value_type (v) != value_enclosing_type (v))
1624 internal_error (__FILE__, __LINE__,
1625 _("Should not be able to create a lazy value with "
1626 "an enclosing type"));
1628 cleanup = make_cleanup (free_current_contents, &buffer);
1630 contents = value_contents_raw (v);
1631 bits_to_skip = 8 * value_offset (v);
1632 if (value_bitsize (v))
1634 bits_to_skip += value_bitpos (v);
1635 type_len = value_bitsize (v);
1638 type_len = 8 * TYPE_LENGTH (value_type (v));
1640 for (i = 0; i < c->n_pieces && offset < type_len; i++)
1642 struct dwarf_expr_piece *p = &c->pieces[i];
1643 size_t this_size, this_size_bits;
1644 long dest_offset_bits, source_offset_bits, source_offset;
1645 const gdb_byte *intermediate_buffer;
1647 /* Compute size, source, and destination offsets for copying, in
1649 this_size_bits = p->size;
1650 if (bits_to_skip > 0 && bits_to_skip >= this_size_bits)
1652 bits_to_skip -= this_size_bits;
1655 if (bits_to_skip > 0)
1657 dest_offset_bits = 0;
1658 source_offset_bits = bits_to_skip;
1659 this_size_bits -= bits_to_skip;
1664 dest_offset_bits = offset;
1665 source_offset_bits = 0;
1667 if (this_size_bits > type_len - offset)
1668 this_size_bits = type_len - offset;
1670 this_size = (this_size_bits + source_offset_bits % 8 + 7) / 8;
1671 source_offset = source_offset_bits / 8;
1672 if (buffer_size < this_size)
1674 buffer_size = this_size;
1675 buffer = xrealloc (buffer, buffer_size);
1677 intermediate_buffer = buffer;
1679 /* Copy from the source to DEST_BUFFER. */
1680 switch (p->location)
1682 case DWARF_VALUE_REGISTER:
1684 struct gdbarch *arch = get_frame_arch (frame);
1685 int gdb_regnum = gdbarch_dwarf2_reg_to_regnum (arch, p->v.regno);
1687 if (gdb_regnum != -1)
1690 int reg_offset = source_offset;
1692 if (gdbarch_byte_order (arch) == BFD_ENDIAN_BIG
1693 && this_size < register_size (arch, gdb_regnum))
1695 /* Big-endian, and we want less than full size. */
1696 reg_offset = register_size (arch, gdb_regnum) - this_size;
1697 /* We want the lower-order THIS_SIZE_BITS of the bytes
1698 we extract from the register. */
1699 source_offset_bits += 8 * this_size - this_size_bits;
1702 if (!get_frame_register_bytes (frame, gdb_regnum, reg_offset,
1706 /* Just so garbage doesn't ever shine through. */
1707 memset (buffer, 0, this_size);
1710 mark_value_bits_optimized_out (v, offset, this_size_bits);
1712 mark_value_bits_unavailable (v, offset, this_size_bits);
1717 error (_("Unable to access DWARF register number %s"),
1718 paddress (arch, p->v.regno));
1723 case DWARF_VALUE_MEMORY:
1724 read_value_memory (v, offset,
1725 p->v.mem.in_stack_memory,
1726 p->v.mem.addr + source_offset,
1730 case DWARF_VALUE_STACK:
1732 size_t n = this_size;
1734 if (n > c->addr_size - source_offset)
1735 n = (c->addr_size >= source_offset
1736 ? c->addr_size - source_offset
1744 const gdb_byte *val_bytes = value_contents_all (p->v.value);
1746 intermediate_buffer = val_bytes + source_offset;
1751 case DWARF_VALUE_LITERAL:
1753 size_t n = this_size;
1755 if (n > p->v.literal.length - source_offset)
1756 n = (p->v.literal.length >= source_offset
1757 ? p->v.literal.length - source_offset
1760 intermediate_buffer = p->v.literal.data + source_offset;
1764 /* These bits show up as zeros -- but do not cause the value
1765 to be considered optimized-out. */
1766 case DWARF_VALUE_IMPLICIT_POINTER:
1769 case DWARF_VALUE_OPTIMIZED_OUT:
1770 mark_value_bits_optimized_out (v, offset, this_size_bits);
1774 internal_error (__FILE__, __LINE__, _("invalid location type"));
1777 if (p->location != DWARF_VALUE_OPTIMIZED_OUT
1778 && p->location != DWARF_VALUE_IMPLICIT_POINTER)
1779 copy_bitwise (contents, dest_offset_bits,
1780 intermediate_buffer, source_offset_bits % 8,
1781 this_size_bits, bits_big_endian);
1783 offset += this_size_bits;
1786 do_cleanups (cleanup);
1790 write_pieced_value (struct value *to, struct value *from)
1794 ULONGEST bits_to_skip;
1795 const gdb_byte *contents;
1796 struct piece_closure *c
1797 = (struct piece_closure *) value_computed_closure (to);
1798 struct frame_info *frame = frame_find_by_id (VALUE_FRAME_ID (to));
1800 size_t buffer_size = 0;
1801 gdb_byte *buffer = NULL;
1802 struct cleanup *cleanup;
1804 = gdbarch_bits_big_endian (get_type_arch (value_type (to)));
1808 mark_value_bytes_optimized_out (to, 0, TYPE_LENGTH (value_type (to)));
1812 cleanup = make_cleanup (free_current_contents, &buffer);
1814 contents = value_contents (from);
1815 bits_to_skip = 8 * value_offset (to);
1816 if (value_bitsize (to))
1818 bits_to_skip += value_bitpos (to);
1819 type_len = value_bitsize (to);
1822 type_len = 8 * TYPE_LENGTH (value_type (to));
1824 for (i = 0; i < c->n_pieces && offset < type_len; i++)
1826 struct dwarf_expr_piece *p = &c->pieces[i];
1827 size_t this_size_bits, this_size;
1828 long dest_offset_bits, source_offset_bits, dest_offset, source_offset;
1830 const gdb_byte *source_buffer;
1832 this_size_bits = p->size;
1833 if (bits_to_skip > 0 && bits_to_skip >= this_size_bits)
1835 bits_to_skip -= this_size_bits;
1838 if (this_size_bits > type_len - offset)
1839 this_size_bits = type_len - offset;
1840 if (bits_to_skip > 0)
1842 dest_offset_bits = bits_to_skip;
1843 source_offset_bits = 0;
1844 this_size_bits -= bits_to_skip;
1849 dest_offset_bits = 0;
1850 source_offset_bits = offset;
1853 this_size = (this_size_bits + source_offset_bits % 8 + 7) / 8;
1854 source_offset = source_offset_bits / 8;
1855 dest_offset = dest_offset_bits / 8;
1856 if (dest_offset_bits % 8 == 0 && source_offset_bits % 8 == 0)
1858 source_buffer = contents + source_offset;
1863 if (buffer_size < this_size)
1865 buffer_size = this_size;
1866 buffer = xrealloc (buffer, buffer_size);
1868 source_buffer = buffer;
1872 switch (p->location)
1874 case DWARF_VALUE_REGISTER:
1876 struct gdbarch *arch = get_frame_arch (frame);
1877 int gdb_regnum = gdbarch_dwarf2_reg_to_regnum (arch, p->v.regno);
1879 if (gdb_regnum != -1)
1881 int reg_offset = dest_offset;
1883 if (gdbarch_byte_order (arch) == BFD_ENDIAN_BIG
1884 && this_size <= register_size (arch, gdb_regnum))
1886 /* Big-endian, and we want less than full size. */
1887 reg_offset = register_size (arch, gdb_regnum) - this_size;
1894 if (!get_frame_register_bytes (frame, gdb_regnum, reg_offset,
1899 throw_error (OPTIMIZED_OUT_ERROR,
1900 _("Can't do read-modify-write to "
1901 "update bitfield; containing word "
1902 "has been optimized out"));
1904 throw_error (NOT_AVAILABLE_ERROR,
1905 _("Can't do read-modify-write to update "
1906 "bitfield; containing word "
1909 copy_bitwise (buffer, dest_offset_bits,
1910 contents, source_offset_bits,
1915 put_frame_register_bytes (frame, gdb_regnum, reg_offset,
1916 this_size, source_buffer);
1920 error (_("Unable to write to DWARF register number %s"),
1921 paddress (arch, p->v.regno));
1925 case DWARF_VALUE_MEMORY:
1928 /* Only the first and last bytes can possibly have any
1930 read_memory (p->v.mem.addr + dest_offset, buffer, 1);
1931 read_memory (p->v.mem.addr + dest_offset + this_size - 1,
1932 buffer + this_size - 1, 1);
1933 copy_bitwise (buffer, dest_offset_bits,
1934 contents, source_offset_bits,
1939 write_memory (p->v.mem.addr + dest_offset,
1940 source_buffer, this_size);
1943 mark_value_bytes_optimized_out (to, 0, TYPE_LENGTH (value_type (to)));
1946 offset += this_size_bits;
1949 do_cleanups (cleanup);
1952 /* An implementation of an lval_funcs method to see whether a value is
1953 a synthetic pointer. */
1956 check_pieced_synthetic_pointer (const struct value *value, int bit_offset,
1959 struct piece_closure *c
1960 = (struct piece_closure *) value_computed_closure (value);
1963 bit_offset += 8 * value_offset (value);
1964 if (value_bitsize (value))
1965 bit_offset += value_bitpos (value);
1967 for (i = 0; i < c->n_pieces && bit_length > 0; i++)
1969 struct dwarf_expr_piece *p = &c->pieces[i];
1970 size_t this_size_bits = p->size;
1974 if (bit_offset >= this_size_bits)
1976 bit_offset -= this_size_bits;
1980 bit_length -= this_size_bits - bit_offset;
1984 bit_length -= this_size_bits;
1986 if (p->location != DWARF_VALUE_IMPLICIT_POINTER)
1993 /* A wrapper function for get_frame_address_in_block. */
1996 get_frame_address_in_block_wrapper (void *baton)
1998 return get_frame_address_in_block (baton);
2001 /* An implementation of an lval_funcs method to indirect through a
2002 pointer. This handles the synthetic pointer case when needed. */
2004 static struct value *
2005 indirect_pieced_value (struct value *value)
2007 struct piece_closure *c
2008 = (struct piece_closure *) value_computed_closure (value);
2010 struct frame_info *frame;
2011 struct dwarf2_locexpr_baton baton;
2012 int i, bit_offset, bit_length;
2013 struct dwarf_expr_piece *piece = NULL;
2014 LONGEST byte_offset;
2016 type = check_typedef (value_type (value));
2017 if (TYPE_CODE (type) != TYPE_CODE_PTR)
2020 bit_length = 8 * TYPE_LENGTH (type);
2021 bit_offset = 8 * value_offset (value);
2022 if (value_bitsize (value))
2023 bit_offset += value_bitpos (value);
2025 for (i = 0; i < c->n_pieces && bit_length > 0; i++)
2027 struct dwarf_expr_piece *p = &c->pieces[i];
2028 size_t this_size_bits = p->size;
2032 if (bit_offset >= this_size_bits)
2034 bit_offset -= this_size_bits;
2038 bit_length -= this_size_bits - bit_offset;
2042 bit_length -= this_size_bits;
2044 if (p->location != DWARF_VALUE_IMPLICIT_POINTER)
2047 if (bit_length != 0)
2048 error (_("Invalid use of DW_OP_GNU_implicit_pointer"));
2054 frame = get_selected_frame (_("No frame selected."));
2056 /* This is an offset requested by GDB, such as value subscripts.
2057 However, due to how synthetic pointers are implemented, this is
2058 always presented to us as a pointer type. This means we have to
2059 sign-extend it manually as appropriate. */
2060 byte_offset = value_as_address (value);
2061 if (TYPE_LENGTH (value_type (value)) < sizeof (LONGEST))
2062 byte_offset = gdb_sign_extend (byte_offset,
2063 8 * TYPE_LENGTH (value_type (value)));
2064 byte_offset += piece->v.ptr.offset;
2068 = dwarf2_fetch_die_loc_sect_off (piece->v.ptr.die, c->per_cu,
2069 get_frame_address_in_block_wrapper,
2072 if (baton.data != NULL)
2073 return dwarf2_evaluate_loc_desc_full (TYPE_TARGET_TYPE (type), frame,
2074 baton.data, baton.size, baton.per_cu,
2078 struct obstack temp_obstack;
2079 struct cleanup *cleanup;
2080 const gdb_byte *bytes;
2082 struct value *result;
2084 obstack_init (&temp_obstack);
2085 cleanup = make_cleanup_obstack_free (&temp_obstack);
2087 bytes = dwarf2_fetch_constant_bytes (piece->v.ptr.die, c->per_cu,
2088 &temp_obstack, &len);
2090 result = allocate_optimized_out_value (TYPE_TARGET_TYPE (type));
2094 || byte_offset + TYPE_LENGTH (TYPE_TARGET_TYPE (type)) > len)
2095 invalid_synthetic_pointer ();
2096 bytes += byte_offset;
2097 result = value_from_contents (TYPE_TARGET_TYPE (type), bytes);
2100 do_cleanups (cleanup);
2106 copy_pieced_value_closure (const struct value *v)
2108 struct piece_closure *c
2109 = (struct piece_closure *) value_computed_closure (v);
2116 free_pieced_value_closure (struct value *v)
2118 struct piece_closure *c
2119 = (struct piece_closure *) value_computed_closure (v);
2126 for (i = 0; i < c->n_pieces; ++i)
2127 if (c->pieces[i].location == DWARF_VALUE_STACK)
2128 value_free (c->pieces[i].v.value);
2135 /* Functions for accessing a variable described by DW_OP_piece. */
2136 static const struct lval_funcs pieced_value_funcs = {
2139 indirect_pieced_value,
2140 NULL, /* coerce_ref */
2141 check_pieced_synthetic_pointer,
2142 copy_pieced_value_closure,
2143 free_pieced_value_closure
2146 /* Virtual method table for dwarf2_evaluate_loc_desc_full below. */
2148 static const struct dwarf_expr_context_funcs dwarf_expr_ctx_funcs =
2150 dwarf_expr_read_addr_from_reg,
2151 dwarf_expr_get_reg_value,
2152 dwarf_expr_read_mem,
2153 dwarf_expr_frame_base,
2154 dwarf_expr_frame_cfa,
2155 dwarf_expr_frame_pc,
2156 dwarf_expr_tls_address,
2157 dwarf_expr_dwarf_call,
2158 dwarf_expr_get_base_type,
2159 dwarf_expr_push_dwarf_reg_entry_value,
2160 dwarf_expr_get_addr_index,
2161 dwarf_expr_get_obj_addr
2164 /* Evaluate a location description, starting at DATA and with length
2165 SIZE, to find the current location of variable of TYPE in the
2166 context of FRAME. BYTE_OFFSET is applied after the contents are
2169 static struct value *
2170 dwarf2_evaluate_loc_desc_full (struct type *type, struct frame_info *frame,
2171 const gdb_byte *data, size_t size,
2172 struct dwarf2_per_cu_data *per_cu,
2173 LONGEST byte_offset)
2175 struct value *retval;
2176 struct dwarf_expr_baton baton;
2177 struct dwarf_expr_context *ctx;
2178 struct cleanup *old_chain, *value_chain;
2179 struct objfile *objfile = dwarf2_per_cu_objfile (per_cu);
2180 volatile struct gdb_exception ex;
2182 if (byte_offset < 0)
2183 invalid_synthetic_pointer ();
2186 return allocate_optimized_out_value (type);
2188 baton.frame = frame;
2189 baton.per_cu = per_cu;
2190 baton.obj_address = 0;
2192 ctx = new_dwarf_expr_context ();
2193 old_chain = make_cleanup_free_dwarf_expr_context (ctx);
2194 value_chain = make_cleanup_value_free_to_mark (value_mark ());
2196 ctx->gdbarch = get_objfile_arch (objfile);
2197 ctx->addr_size = dwarf2_per_cu_addr_size (per_cu);
2198 ctx->ref_addr_size = dwarf2_per_cu_ref_addr_size (per_cu);
2199 ctx->offset = dwarf2_per_cu_text_offset (per_cu);
2200 ctx->baton = &baton;
2201 ctx->funcs = &dwarf_expr_ctx_funcs;
2203 TRY_CATCH (ex, RETURN_MASK_ERROR)
2205 dwarf_expr_eval (ctx, data, size);
2209 if (ex.error == NOT_AVAILABLE_ERROR)
2211 do_cleanups (old_chain);
2212 retval = allocate_value (type);
2213 mark_value_bytes_unavailable (retval, 0, TYPE_LENGTH (type));
2216 else if (ex.error == NO_ENTRY_VALUE_ERROR)
2218 if (entry_values_debug)
2219 exception_print (gdb_stdout, ex);
2220 do_cleanups (old_chain);
2221 return allocate_optimized_out_value (type);
2224 throw_exception (ex);
2227 if (ctx->num_pieces > 0)
2229 struct piece_closure *c;
2230 struct frame_id frame_id = get_frame_id (frame);
2231 ULONGEST bit_size = 0;
2234 for (i = 0; i < ctx->num_pieces; ++i)
2235 bit_size += ctx->pieces[i].size;
2236 if (8 * (byte_offset + TYPE_LENGTH (type)) > bit_size)
2237 invalid_synthetic_pointer ();
2239 c = allocate_piece_closure (per_cu, ctx->num_pieces, ctx->pieces,
2241 /* We must clean up the value chain after creating the piece
2242 closure but before allocating the result. */
2243 do_cleanups (value_chain);
2244 retval = allocate_computed_value (type, &pieced_value_funcs, c);
2245 VALUE_FRAME_ID (retval) = frame_id;
2246 set_value_offset (retval, byte_offset);
2250 switch (ctx->location)
2252 case DWARF_VALUE_REGISTER:
2254 struct gdbarch *arch = get_frame_arch (frame);
2256 = longest_to_int (value_as_long (dwarf_expr_fetch (ctx, 0)));
2257 int gdb_regnum = gdbarch_dwarf2_reg_to_regnum (arch, dwarf_regnum);
2259 if (byte_offset != 0)
2260 error (_("cannot use offset on synthetic pointer to register"));
2261 do_cleanups (value_chain);
2262 if (gdb_regnum == -1)
2263 error (_("Unable to access DWARF register number %d"),
2265 retval = value_from_register (type, gdb_regnum, frame);
2266 if (value_optimized_out (retval))
2270 /* This means the register has undefined value / was
2271 not saved. As we're computing the location of some
2272 variable etc. in the program, not a value for
2273 inspecting a register ($pc, $sp, etc.), return a
2274 generic optimized out value instead, so that we show
2275 <optimized out> instead of <not saved>. */
2276 do_cleanups (value_chain);
2277 tmp = allocate_value (type);
2278 value_contents_copy (tmp, 0, retval, 0, TYPE_LENGTH (type));
2284 case DWARF_VALUE_MEMORY:
2286 CORE_ADDR address = dwarf_expr_fetch_address (ctx, 0);
2287 int in_stack_memory = dwarf_expr_fetch_in_stack_memory (ctx, 0);
2289 do_cleanups (value_chain);
2290 retval = value_at_lazy (type, address + byte_offset);
2291 if (in_stack_memory)
2292 set_value_stack (retval, 1);
2296 case DWARF_VALUE_STACK:
2298 struct value *value = dwarf_expr_fetch (ctx, 0);
2300 const gdb_byte *val_bytes;
2301 size_t n = TYPE_LENGTH (value_type (value));
2303 if (byte_offset + TYPE_LENGTH (type) > n)
2304 invalid_synthetic_pointer ();
2306 val_bytes = value_contents_all (value);
2307 val_bytes += byte_offset;
2310 /* Preserve VALUE because we are going to free values back
2311 to the mark, but we still need the value contents
2313 value_incref (value);
2314 do_cleanups (value_chain);
2315 make_cleanup_value_free (value);
2317 retval = allocate_value (type);
2318 contents = value_contents_raw (retval);
2319 if (n > TYPE_LENGTH (type))
2321 struct gdbarch *objfile_gdbarch = get_objfile_arch (objfile);
2323 if (gdbarch_byte_order (objfile_gdbarch) == BFD_ENDIAN_BIG)
2324 val_bytes += n - TYPE_LENGTH (type);
2325 n = TYPE_LENGTH (type);
2327 memcpy (contents, val_bytes, n);
2331 case DWARF_VALUE_LITERAL:
2334 const bfd_byte *ldata;
2335 size_t n = ctx->len;
2337 if (byte_offset + TYPE_LENGTH (type) > n)
2338 invalid_synthetic_pointer ();
2340 do_cleanups (value_chain);
2341 retval = allocate_value (type);
2342 contents = value_contents_raw (retval);
2344 ldata = ctx->data + byte_offset;
2347 if (n > TYPE_LENGTH (type))
2349 struct gdbarch *objfile_gdbarch = get_objfile_arch (objfile);
2351 if (gdbarch_byte_order (objfile_gdbarch) == BFD_ENDIAN_BIG)
2352 ldata += n - TYPE_LENGTH (type);
2353 n = TYPE_LENGTH (type);
2355 memcpy (contents, ldata, n);
2359 case DWARF_VALUE_OPTIMIZED_OUT:
2360 do_cleanups (value_chain);
2361 retval = allocate_optimized_out_value (type);
2364 /* DWARF_VALUE_IMPLICIT_POINTER was converted to a pieced
2365 operation by execute_stack_op. */
2366 case DWARF_VALUE_IMPLICIT_POINTER:
2367 /* DWARF_VALUE_OPTIMIZED_OUT can't occur in this context --
2368 it can only be encountered when making a piece. */
2370 internal_error (__FILE__, __LINE__, _("invalid location type"));
2374 set_value_initialized (retval, ctx->initialized);
2376 do_cleanups (old_chain);
2381 /* The exported interface to dwarf2_evaluate_loc_desc_full; it always
2382 passes 0 as the byte_offset. */
2385 dwarf2_evaluate_loc_desc (struct type *type, struct frame_info *frame,
2386 const gdb_byte *data, size_t size,
2387 struct dwarf2_per_cu_data *per_cu)
2389 return dwarf2_evaluate_loc_desc_full (type, frame, data, size, per_cu, 0);
2392 /* Evaluates a dwarf expression and stores the result in VAL, expecting
2393 that the dwarf expression only produces a single CORE_ADDR. ADDR is a
2394 context (location of a variable) and might be needed to evaluate the
2395 location expression.
2396 Returns 1 on success, 0 otherwise. */
2399 dwarf2_locexpr_baton_eval (const struct dwarf2_locexpr_baton *dlbaton,
2403 struct dwarf_expr_context *ctx;
2404 struct dwarf_expr_baton baton;
2405 struct objfile *objfile;
2406 struct cleanup *cleanup;
2408 if (dlbaton == NULL || dlbaton->size == 0)
2411 ctx = new_dwarf_expr_context ();
2412 cleanup = make_cleanup_free_dwarf_expr_context (ctx);
2414 baton.frame = get_selected_frame (NULL);
2415 baton.per_cu = dlbaton->per_cu;
2416 baton.obj_address = addr;
2418 objfile = dwarf2_per_cu_objfile (dlbaton->per_cu);
2420 ctx->gdbarch = get_objfile_arch (objfile);
2421 ctx->addr_size = dwarf2_per_cu_addr_size (dlbaton->per_cu);
2422 ctx->ref_addr_size = dwarf2_per_cu_ref_addr_size (dlbaton->per_cu);
2423 ctx->offset = dwarf2_per_cu_text_offset (dlbaton->per_cu);
2424 ctx->funcs = &dwarf_expr_ctx_funcs;
2425 ctx->baton = &baton;
2427 dwarf_expr_eval (ctx, dlbaton->data, dlbaton->size);
2429 switch (ctx->location)
2431 case DWARF_VALUE_REGISTER:
2432 case DWARF_VALUE_MEMORY:
2433 case DWARF_VALUE_STACK:
2434 *valp = dwarf_expr_fetch_address (ctx, 0);
2435 if (ctx->location == DWARF_VALUE_REGISTER)
2436 *valp = dwarf_expr_read_addr_from_reg (&baton, *valp);
2437 do_cleanups (cleanup);
2439 case DWARF_VALUE_LITERAL:
2440 *valp = extract_signed_integer (ctx->data, ctx->len,
2441 gdbarch_byte_order (ctx->gdbarch));
2442 do_cleanups (cleanup);
2444 /* Unsupported dwarf values. */
2445 case DWARF_VALUE_OPTIMIZED_OUT:
2446 case DWARF_VALUE_IMPLICIT_POINTER:
2450 do_cleanups (cleanup);
2454 /* See dwarf2loc.h. */
2457 dwarf2_evaluate_property (const struct dynamic_prop *prop,
2458 CORE_ADDR address, CORE_ADDR *value)
2467 const struct dwarf2_property_baton *baton = prop->data.baton;
2469 if (dwarf2_locexpr_baton_eval (&baton->locexpr, address, value))
2471 if (baton->referenced_type)
2473 struct value *val = value_at (baton->referenced_type, *value);
2475 *value = value_as_address (val);
2484 struct dwarf2_property_baton *baton = prop->data.baton;
2485 struct frame_info *frame = get_selected_frame (NULL);
2486 CORE_ADDR pc = get_frame_address_in_block (frame);
2487 const gdb_byte *data;
2491 data = dwarf2_find_location_expression (&baton->loclist, &size, pc);
2494 val = dwarf2_evaluate_loc_desc (baton->referenced_type, frame, data,
2495 size, baton->loclist.per_cu);
2496 if (!value_optimized_out (val))
2498 *value = value_as_address (val);
2506 *value = prop->data.const_val;
2513 /* See dwarf2loc.h. */
2516 dwarf2_compile_property_to_c (struct ui_file *stream,
2517 const char *result_name,
2518 struct gdbarch *gdbarch,
2519 unsigned char *registers_used,
2520 const struct dynamic_prop *prop,
2524 struct dwarf2_property_baton *baton = prop->data.baton;
2525 const gdb_byte *data;
2527 struct dwarf2_per_cu_data *per_cu;
2529 if (prop->kind == PROP_LOCEXPR)
2531 data = baton->locexpr.data;
2532 size = baton->locexpr.size;
2533 per_cu = baton->locexpr.per_cu;
2537 gdb_assert (prop->kind == PROP_LOCLIST);
2539 data = dwarf2_find_location_expression (&baton->loclist, &size, pc);
2540 per_cu = baton->loclist.per_cu;
2543 compile_dwarf_bounds_to_c (stream, result_name, prop, sym, pc,
2544 gdbarch, registers_used,
2545 dwarf2_per_cu_addr_size (per_cu),
2546 data, data + size, per_cu);
2550 /* Helper functions and baton for dwarf2_loc_desc_needs_frame. */
2552 struct needs_frame_baton
2555 struct dwarf2_per_cu_data *per_cu;
2558 /* Reads from registers do require a frame. */
2560 needs_frame_read_addr_from_reg (void *baton, int regnum)
2562 struct needs_frame_baton *nf_baton = baton;
2564 nf_baton->needs_frame = 1;
2568 /* struct dwarf_expr_context_funcs' "get_reg_value" callback:
2569 Reads from registers do require a frame. */
2571 static struct value *
2572 needs_frame_get_reg_value (void *baton, struct type *type, int regnum)
2574 struct needs_frame_baton *nf_baton = baton;
2576 nf_baton->needs_frame = 1;
2577 return value_zero (type, not_lval);
2580 /* Reads from memory do not require a frame. */
2582 needs_frame_read_mem (void *baton, gdb_byte *buf, CORE_ADDR addr, size_t len)
2584 memset (buf, 0, len);
2587 /* Frame-relative accesses do require a frame. */
2589 needs_frame_frame_base (void *baton, const gdb_byte **start, size_t * length)
2591 static gdb_byte lit0 = DW_OP_lit0;
2592 struct needs_frame_baton *nf_baton = baton;
2597 nf_baton->needs_frame = 1;
2600 /* CFA accesses require a frame. */
2603 needs_frame_frame_cfa (void *baton)
2605 struct needs_frame_baton *nf_baton = baton;
2607 nf_baton->needs_frame = 1;
2611 /* Thread-local accesses do require a frame. */
2613 needs_frame_tls_address (void *baton, CORE_ADDR offset)
2615 struct needs_frame_baton *nf_baton = baton;
2617 nf_baton->needs_frame = 1;
2621 /* Helper interface of per_cu_dwarf_call for dwarf2_loc_desc_needs_frame. */
2624 needs_frame_dwarf_call (struct dwarf_expr_context *ctx, cu_offset die_offset)
2626 struct needs_frame_baton *nf_baton = ctx->baton;
2628 per_cu_dwarf_call (ctx, die_offset, nf_baton->per_cu,
2629 ctx->funcs->get_frame_pc, ctx->baton);
2632 /* DW_OP_GNU_entry_value accesses require a caller, therefore a frame. */
2635 needs_dwarf_reg_entry_value (struct dwarf_expr_context *ctx,
2636 enum call_site_parameter_kind kind,
2637 union call_site_parameter_u kind_u, int deref_size)
2639 struct needs_frame_baton *nf_baton = ctx->baton;
2641 nf_baton->needs_frame = 1;
2643 /* The expression may require some stub values on DWARF stack. */
2644 dwarf_expr_push_address (ctx, 0, 0);
2647 /* DW_OP_GNU_addr_index doesn't require a frame. */
2650 needs_get_addr_index (void *baton, unsigned int index)
2652 /* Nothing to do. */
2656 /* DW_OP_push_object_address has a frame already passed through. */
2659 needs_get_obj_addr (void *baton)
2661 /* Nothing to do. */
2665 /* Virtual method table for dwarf2_loc_desc_needs_frame below. */
2667 static const struct dwarf_expr_context_funcs needs_frame_ctx_funcs =
2669 needs_frame_read_addr_from_reg,
2670 needs_frame_get_reg_value,
2671 needs_frame_read_mem,
2672 needs_frame_frame_base,
2673 needs_frame_frame_cfa,
2674 needs_frame_frame_cfa, /* get_frame_pc */
2675 needs_frame_tls_address,
2676 needs_frame_dwarf_call,
2677 NULL, /* get_base_type */
2678 needs_dwarf_reg_entry_value,
2679 needs_get_addr_index,
2683 /* Return non-zero iff the location expression at DATA (length SIZE)
2684 requires a frame to evaluate. */
2687 dwarf2_loc_desc_needs_frame (const gdb_byte *data, size_t size,
2688 struct dwarf2_per_cu_data *per_cu)
2690 struct needs_frame_baton baton;
2691 struct dwarf_expr_context *ctx;
2693 struct cleanup *old_chain;
2694 struct objfile *objfile = dwarf2_per_cu_objfile (per_cu);
2696 baton.needs_frame = 0;
2697 baton.per_cu = per_cu;
2699 ctx = new_dwarf_expr_context ();
2700 old_chain = make_cleanup_free_dwarf_expr_context (ctx);
2701 make_cleanup_value_free_to_mark (value_mark ());
2703 ctx->gdbarch = get_objfile_arch (objfile);
2704 ctx->addr_size = dwarf2_per_cu_addr_size (per_cu);
2705 ctx->ref_addr_size = dwarf2_per_cu_ref_addr_size (per_cu);
2706 ctx->offset = dwarf2_per_cu_text_offset (per_cu);
2707 ctx->baton = &baton;
2708 ctx->funcs = &needs_frame_ctx_funcs;
2710 dwarf_expr_eval (ctx, data, size);
2712 in_reg = ctx->location == DWARF_VALUE_REGISTER;
2714 if (ctx->num_pieces > 0)
2718 /* If the location has several pieces, and any of them are in
2719 registers, then we will need a frame to fetch them from. */
2720 for (i = 0; i < ctx->num_pieces; i++)
2721 if (ctx->pieces[i].location == DWARF_VALUE_REGISTER)
2725 do_cleanups (old_chain);
2727 return baton.needs_frame || in_reg;
2730 /* A helper function that throws an unimplemented error mentioning a
2731 given DWARF operator. */
2734 unimplemented (unsigned int op)
2736 const char *name = get_DW_OP_name (op);
2739 error (_("DWARF operator %s cannot be translated to an agent expression"),
2742 error (_("Unknown DWARF operator 0x%02x cannot be translated "
2743 "to an agent expression"),
2747 /* See dwarf2loc.h. */
2750 dwarf2_reg_to_regnum_or_error (struct gdbarch *arch, int dwarf_reg)
2752 int reg = gdbarch_dwarf2_reg_to_regnum (arch, dwarf_reg);
2754 error (_("Unable to access DWARF register number %d"), dwarf_reg);
2758 /* A helper function that emits an access to memory. ARCH is the
2759 target architecture. EXPR is the expression which we are building.
2760 NBITS is the number of bits we want to read. This emits the
2761 opcodes needed to read the memory and then extract the desired
2765 access_memory (struct gdbarch *arch, struct agent_expr *expr, ULONGEST nbits)
2767 ULONGEST nbytes = (nbits + 7) / 8;
2769 gdb_assert (nbytes > 0 && nbytes <= sizeof (LONGEST));
2772 ax_trace_quick (expr, nbytes);
2775 ax_simple (expr, aop_ref8);
2776 else if (nbits <= 16)
2777 ax_simple (expr, aop_ref16);
2778 else if (nbits <= 32)
2779 ax_simple (expr, aop_ref32);
2781 ax_simple (expr, aop_ref64);
2783 /* If we read exactly the number of bytes we wanted, we're done. */
2784 if (8 * nbytes == nbits)
2787 if (gdbarch_bits_big_endian (arch))
2789 /* On a bits-big-endian machine, we want the high-order
2791 ax_const_l (expr, 8 * nbytes - nbits);
2792 ax_simple (expr, aop_rsh_unsigned);
2796 /* On a bits-little-endian box, we want the low-order NBITS. */
2797 ax_zero_ext (expr, nbits);
2801 /* A helper function to return the frame's PC. */
2804 get_ax_pc (void *baton)
2806 struct agent_expr *expr = baton;
2811 /* Compile a DWARF location expression to an agent expression.
2813 EXPR is the agent expression we are building.
2814 LOC is the agent value we modify.
2815 ARCH is the architecture.
2816 ADDR_SIZE is the size of addresses, in bytes.
2817 OP_PTR is the start of the location expression.
2818 OP_END is one past the last byte of the location expression.
2820 This will throw an exception for various kinds of errors -- for
2821 example, if the expression cannot be compiled, or if the expression
2825 dwarf2_compile_expr_to_ax (struct agent_expr *expr, struct axs_value *loc,
2826 struct gdbarch *arch, unsigned int addr_size,
2827 const gdb_byte *op_ptr, const gdb_byte *op_end,
2828 struct dwarf2_per_cu_data *per_cu)
2830 struct cleanup *cleanups;
2832 VEC(int) *dw_labels = NULL, *patches = NULL;
2833 const gdb_byte * const base = op_ptr;
2834 const gdb_byte *previous_piece = op_ptr;
2835 enum bfd_endian byte_order = gdbarch_byte_order (arch);
2836 ULONGEST bits_collected = 0;
2837 unsigned int addr_size_bits = 8 * addr_size;
2838 int bits_big_endian = gdbarch_bits_big_endian (arch);
2840 offsets = xmalloc ((op_end - op_ptr) * sizeof (int));
2841 cleanups = make_cleanup (xfree, offsets);
2843 for (i = 0; i < op_end - op_ptr; ++i)
2846 make_cleanup (VEC_cleanup (int), &dw_labels);
2847 make_cleanup (VEC_cleanup (int), &patches);
2849 /* By default we are making an address. */
2850 loc->kind = axs_lvalue_memory;
2852 while (op_ptr < op_end)
2854 enum dwarf_location_atom op = *op_ptr;
2855 uint64_t uoffset, reg;
2859 offsets[op_ptr - base] = expr->len;
2862 /* Our basic approach to code generation is to map DWARF
2863 operations directly to AX operations. However, there are
2866 First, DWARF works on address-sized units, but AX always uses
2867 LONGEST. For most operations we simply ignore this
2868 difference; instead we generate sign extensions as needed
2869 before division and comparison operations. It would be nice
2870 to omit the sign extensions, but there is no way to determine
2871 the size of the target's LONGEST. (This code uses the size
2872 of the host LONGEST in some cases -- that is a bug but it is
2875 Second, some DWARF operations cannot be translated to AX.
2876 For these we simply fail. See
2877 http://sourceware.org/bugzilla/show_bug.cgi?id=11662. */
2912 ax_const_l (expr, op - DW_OP_lit0);
2916 uoffset = extract_unsigned_integer (op_ptr, addr_size, byte_order);
2917 op_ptr += addr_size;
2918 /* Some versions of GCC emit DW_OP_addr before
2919 DW_OP_GNU_push_tls_address. In this case the value is an
2920 index, not an address. We don't support things like
2921 branching between the address and the TLS op. */
2922 if (op_ptr >= op_end || *op_ptr != DW_OP_GNU_push_tls_address)
2923 uoffset += dwarf2_per_cu_text_offset (per_cu);
2924 ax_const_l (expr, uoffset);
2928 ax_const_l (expr, extract_unsigned_integer (op_ptr, 1, byte_order));
2932 ax_const_l (expr, extract_signed_integer (op_ptr, 1, byte_order));
2936 ax_const_l (expr, extract_unsigned_integer (op_ptr, 2, byte_order));
2940 ax_const_l (expr, extract_signed_integer (op_ptr, 2, byte_order));
2944 ax_const_l (expr, extract_unsigned_integer (op_ptr, 4, byte_order));
2948 ax_const_l (expr, extract_signed_integer (op_ptr, 4, byte_order));
2952 ax_const_l (expr, extract_unsigned_integer (op_ptr, 8, byte_order));
2956 ax_const_l (expr, extract_signed_integer (op_ptr, 8, byte_order));
2960 op_ptr = safe_read_uleb128 (op_ptr, op_end, &uoffset);
2961 ax_const_l (expr, uoffset);
2964 op_ptr = safe_read_sleb128 (op_ptr, op_end, &offset);
2965 ax_const_l (expr, offset);
3000 dwarf_expr_require_composition (op_ptr, op_end, "DW_OP_regx");
3001 loc->u.reg = dwarf2_reg_to_regnum_or_error (arch, op - DW_OP_reg0);
3002 loc->kind = axs_lvalue_register;
3006 op_ptr = safe_read_uleb128 (op_ptr, op_end, ®);
3007 dwarf_expr_require_composition (op_ptr, op_end, "DW_OP_regx");
3008 loc->u.reg = dwarf2_reg_to_regnum_or_error (arch, reg);
3009 loc->kind = axs_lvalue_register;
3012 case DW_OP_implicit_value:
3016 op_ptr = safe_read_uleb128 (op_ptr, op_end, &len);
3017 if (op_ptr + len > op_end)
3018 error (_("DW_OP_implicit_value: too few bytes available."));
3019 if (len > sizeof (ULONGEST))
3020 error (_("Cannot translate DW_OP_implicit_value of %d bytes"),
3023 ax_const_l (expr, extract_unsigned_integer (op_ptr, len,
3026 dwarf_expr_require_composition (op_ptr, op_end,
3027 "DW_OP_implicit_value");
3029 loc->kind = axs_rvalue;
3033 case DW_OP_stack_value:
3034 dwarf_expr_require_composition (op_ptr, op_end, "DW_OP_stack_value");
3035 loc->kind = axs_rvalue;
3070 op_ptr = safe_read_sleb128 (op_ptr, op_end, &offset);
3071 i = dwarf2_reg_to_regnum_or_error (arch, op - DW_OP_breg0);
3075 ax_const_l (expr, offset);
3076 ax_simple (expr, aop_add);
3081 op_ptr = safe_read_uleb128 (op_ptr, op_end, ®);
3082 op_ptr = safe_read_sleb128 (op_ptr, op_end, &offset);
3083 i = dwarf2_reg_to_regnum_or_error (arch, reg);
3087 ax_const_l (expr, offset);
3088 ax_simple (expr, aop_add);
3094 const gdb_byte *datastart;
3096 const struct block *b;
3097 struct symbol *framefunc;
3099 b = block_for_pc (expr->scope);
3102 error (_("No block found for address"));
3104 framefunc = block_linkage_function (b);
3107 error (_("No function found for block"));
3109 func_get_frame_base_dwarf_block (framefunc, expr->scope,
3110 &datastart, &datalen);
3112 op_ptr = safe_read_sleb128 (op_ptr, op_end, &offset);
3113 dwarf2_compile_expr_to_ax (expr, loc, arch, addr_size, datastart,
3114 datastart + datalen, per_cu);
3115 if (loc->kind == axs_lvalue_register)
3116 require_rvalue (expr, loc);
3120 ax_const_l (expr, offset);
3121 ax_simple (expr, aop_add);
3124 loc->kind = axs_lvalue_memory;
3129 ax_simple (expr, aop_dup);
3133 ax_simple (expr, aop_pop);
3138 ax_pick (expr, offset);
3142 ax_simple (expr, aop_swap);
3150 ax_simple (expr, aop_rot);
3154 case DW_OP_deref_size:
3158 if (op == DW_OP_deref_size)
3163 if (size != 1 && size != 2 && size != 4 && size != 8)
3164 error (_("Unsupported size %d in %s"),
3165 size, get_DW_OP_name (op));
3166 access_memory (arch, expr, size * TARGET_CHAR_BIT);
3171 /* Sign extend the operand. */
3172 ax_ext (expr, addr_size_bits);
3173 ax_simple (expr, aop_dup);
3174 ax_const_l (expr, 0);
3175 ax_simple (expr, aop_less_signed);
3176 ax_simple (expr, aop_log_not);
3177 i = ax_goto (expr, aop_if_goto);
3178 /* We have to emit 0 - X. */
3179 ax_const_l (expr, 0);
3180 ax_simple (expr, aop_swap);
3181 ax_simple (expr, aop_sub);
3182 ax_label (expr, i, expr->len);
3186 /* No need to sign extend here. */
3187 ax_const_l (expr, 0);
3188 ax_simple (expr, aop_swap);
3189 ax_simple (expr, aop_sub);
3193 /* Sign extend the operand. */
3194 ax_ext (expr, addr_size_bits);
3195 ax_simple (expr, aop_bit_not);
3198 case DW_OP_plus_uconst:
3199 op_ptr = safe_read_uleb128 (op_ptr, op_end, ®);
3200 /* It would be really weird to emit `DW_OP_plus_uconst 0',
3201 but we micro-optimize anyhow. */
3204 ax_const_l (expr, reg);
3205 ax_simple (expr, aop_add);
3210 ax_simple (expr, aop_bit_and);
3214 /* Sign extend the operands. */
3215 ax_ext (expr, addr_size_bits);
3216 ax_simple (expr, aop_swap);
3217 ax_ext (expr, addr_size_bits);
3218 ax_simple (expr, aop_swap);
3219 ax_simple (expr, aop_div_signed);
3223 ax_simple (expr, aop_sub);
3227 ax_simple (expr, aop_rem_unsigned);
3231 ax_simple (expr, aop_mul);
3235 ax_simple (expr, aop_bit_or);
3239 ax_simple (expr, aop_add);
3243 ax_simple (expr, aop_lsh);
3247 ax_simple (expr, aop_rsh_unsigned);
3251 ax_simple (expr, aop_rsh_signed);
3255 ax_simple (expr, aop_bit_xor);
3259 /* Sign extend the operands. */
3260 ax_ext (expr, addr_size_bits);
3261 ax_simple (expr, aop_swap);
3262 ax_ext (expr, addr_size_bits);
3263 /* Note no swap here: A <= B is !(B < A). */
3264 ax_simple (expr, aop_less_signed);
3265 ax_simple (expr, aop_log_not);
3269 /* Sign extend the operands. */
3270 ax_ext (expr, addr_size_bits);
3271 ax_simple (expr, aop_swap);
3272 ax_ext (expr, addr_size_bits);
3273 ax_simple (expr, aop_swap);
3274 /* A >= B is !(A < B). */
3275 ax_simple (expr, aop_less_signed);
3276 ax_simple (expr, aop_log_not);
3280 /* Sign extend the operands. */
3281 ax_ext (expr, addr_size_bits);
3282 ax_simple (expr, aop_swap);
3283 ax_ext (expr, addr_size_bits);
3284 /* No need for a second swap here. */
3285 ax_simple (expr, aop_equal);
3289 /* Sign extend the operands. */
3290 ax_ext (expr, addr_size_bits);
3291 ax_simple (expr, aop_swap);
3292 ax_ext (expr, addr_size_bits);
3293 ax_simple (expr, aop_swap);
3294 ax_simple (expr, aop_less_signed);
3298 /* Sign extend the operands. */
3299 ax_ext (expr, addr_size_bits);
3300 ax_simple (expr, aop_swap);
3301 ax_ext (expr, addr_size_bits);
3302 /* Note no swap here: A > B is B < A. */
3303 ax_simple (expr, aop_less_signed);
3307 /* Sign extend the operands. */
3308 ax_ext (expr, addr_size_bits);
3309 ax_simple (expr, aop_swap);
3310 ax_ext (expr, addr_size_bits);
3311 /* No need for a swap here. */
3312 ax_simple (expr, aop_equal);
3313 ax_simple (expr, aop_log_not);
3316 case DW_OP_call_frame_cfa:
3319 CORE_ADDR text_offset;
3321 const gdb_byte *cfa_start, *cfa_end;
3323 if (dwarf2_fetch_cfa_info (arch, expr->scope, per_cu,
3325 &text_offset, &cfa_start, &cfa_end))
3328 ax_reg (expr, regnum);
3331 ax_const_l (expr, off);
3332 ax_simple (expr, aop_add);
3337 /* Another expression. */
3338 ax_const_l (expr, text_offset);
3339 dwarf2_compile_expr_to_ax (expr, loc, arch, addr_size,
3340 cfa_start, cfa_end, per_cu);
3343 loc->kind = axs_lvalue_memory;
3347 case DW_OP_GNU_push_tls_address:
3351 case DW_OP_push_object_address:
3356 offset = extract_signed_integer (op_ptr, 2, byte_order);
3358 i = ax_goto (expr, aop_goto);
3359 VEC_safe_push (int, dw_labels, op_ptr + offset - base);
3360 VEC_safe_push (int, patches, i);
3364 offset = extract_signed_integer (op_ptr, 2, byte_order);
3366 /* Zero extend the operand. */
3367 ax_zero_ext (expr, addr_size_bits);
3368 i = ax_goto (expr, aop_if_goto);
3369 VEC_safe_push (int, dw_labels, op_ptr + offset - base);
3370 VEC_safe_push (int, patches, i);
3377 case DW_OP_bit_piece:
3379 uint64_t size, offset;
3381 if (op_ptr - 1 == previous_piece)
3382 error (_("Cannot translate empty pieces to agent expressions"));
3383 previous_piece = op_ptr - 1;
3385 op_ptr = safe_read_uleb128 (op_ptr, op_end, &size);
3386 if (op == DW_OP_piece)
3392 op_ptr = safe_read_uleb128 (op_ptr, op_end, &offset);
3394 if (bits_collected + size > 8 * sizeof (LONGEST))
3395 error (_("Expression pieces exceed word size"));
3397 /* Access the bits. */
3400 case axs_lvalue_register:
3401 ax_reg (expr, loc->u.reg);
3404 case axs_lvalue_memory:
3405 /* Offset the pointer, if needed. */
3408 ax_const_l (expr, offset / 8);
3409 ax_simple (expr, aop_add);
3412 access_memory (arch, expr, size);
3416 /* For a bits-big-endian target, shift up what we already
3417 have. For a bits-little-endian target, shift up the
3418 new data. Note that there is a potential bug here if
3419 the DWARF expression leaves multiple values on the
3421 if (bits_collected > 0)
3423 if (bits_big_endian)
3425 ax_simple (expr, aop_swap);
3426 ax_const_l (expr, size);
3427 ax_simple (expr, aop_lsh);
3428 /* We don't need a second swap here, because
3429 aop_bit_or is symmetric. */
3433 ax_const_l (expr, size);
3434 ax_simple (expr, aop_lsh);
3436 ax_simple (expr, aop_bit_or);
3439 bits_collected += size;
3440 loc->kind = axs_rvalue;
3444 case DW_OP_GNU_uninit:
3450 struct dwarf2_locexpr_baton block;
3451 int size = (op == DW_OP_call2 ? 2 : 4);
3454 uoffset = extract_unsigned_integer (op_ptr, size, byte_order);
3457 offset.cu_off = uoffset;
3458 block = dwarf2_fetch_die_loc_cu_off (offset, per_cu,
3461 /* DW_OP_call_ref is currently not supported. */
3462 gdb_assert (block.per_cu == per_cu);
3464 dwarf2_compile_expr_to_ax (expr, loc, arch, addr_size,
3465 block.data, block.data + block.size,
3470 case DW_OP_call_ref:
3478 /* Patch all the branches we emitted. */
3479 for (i = 0; i < VEC_length (int, patches); ++i)
3481 int targ = offsets[VEC_index (int, dw_labels, i)];
3483 internal_error (__FILE__, __LINE__, _("invalid label"));
3484 ax_label (expr, VEC_index (int, patches, i), targ);
3487 do_cleanups (cleanups);
3491 /* Return the value of SYMBOL in FRAME using the DWARF-2 expression
3492 evaluator to calculate the location. */
3493 static struct value *
3494 locexpr_read_variable (struct symbol *symbol, struct frame_info *frame)
3496 struct dwarf2_locexpr_baton *dlbaton = SYMBOL_LOCATION_BATON (symbol);
3499 val = dwarf2_evaluate_loc_desc (SYMBOL_TYPE (symbol), frame, dlbaton->data,
3500 dlbaton->size, dlbaton->per_cu);
3505 /* Return the value of SYMBOL in FRAME at (callee) FRAME's function
3506 entry. SYMBOL should be a function parameter, otherwise NO_ENTRY_VALUE_ERROR
3509 static struct value *
3510 locexpr_read_variable_at_entry (struct symbol *symbol, struct frame_info *frame)
3512 struct dwarf2_locexpr_baton *dlbaton = SYMBOL_LOCATION_BATON (symbol);
3514 return value_of_dwarf_block_entry (SYMBOL_TYPE (symbol), frame, dlbaton->data,
3518 /* Return non-zero iff we need a frame to evaluate SYMBOL. */
3520 locexpr_read_needs_frame (struct symbol *symbol)
3522 struct dwarf2_locexpr_baton *dlbaton = SYMBOL_LOCATION_BATON (symbol);
3524 return dwarf2_loc_desc_needs_frame (dlbaton->data, dlbaton->size,
3528 /* Return true if DATA points to the end of a piece. END is one past
3529 the last byte in the expression. */
3532 piece_end_p (const gdb_byte *data, const gdb_byte *end)
3534 return data == end || data[0] == DW_OP_piece || data[0] == DW_OP_bit_piece;
3537 /* Helper for locexpr_describe_location_piece that finds the name of a
3541 locexpr_regname (struct gdbarch *gdbarch, int dwarf_regnum)
3545 regnum = gdbarch_dwarf2_reg_to_regnum (gdbarch, dwarf_regnum);
3546 return gdbarch_register_name (gdbarch, regnum);
3549 /* Nicely describe a single piece of a location, returning an updated
3550 position in the bytecode sequence. This function cannot recognize
3551 all locations; if a location is not recognized, it simply returns
3552 DATA. If there is an error during reading, e.g. we run off the end
3553 of the buffer, an error is thrown. */
3555 static const gdb_byte *
3556 locexpr_describe_location_piece (struct symbol *symbol, struct ui_file *stream,
3557 CORE_ADDR addr, struct objfile *objfile,
3558 struct dwarf2_per_cu_data *per_cu,
3559 const gdb_byte *data, const gdb_byte *end,
3560 unsigned int addr_size)
3562 struct gdbarch *gdbarch = get_objfile_arch (objfile);
3565 if (data[0] >= DW_OP_reg0 && data[0] <= DW_OP_reg31)
3567 fprintf_filtered (stream, _("a variable in $%s"),
3568 locexpr_regname (gdbarch, data[0] - DW_OP_reg0));
3571 else if (data[0] == DW_OP_regx)
3575 data = safe_read_uleb128 (data + 1, end, ®);
3576 fprintf_filtered (stream, _("a variable in $%s"),
3577 locexpr_regname (gdbarch, reg));
3579 else if (data[0] == DW_OP_fbreg)
3581 const struct block *b;
3582 struct symbol *framefunc;
3584 int64_t frame_offset;
3585 const gdb_byte *base_data, *new_data, *save_data = data;
3587 int64_t base_offset = 0;
3589 new_data = safe_read_sleb128 (data + 1, end, &frame_offset);
3590 if (!piece_end_p (new_data, end))
3594 b = block_for_pc (addr);
3597 error (_("No block found for address for symbol \"%s\"."),
3598 SYMBOL_PRINT_NAME (symbol));
3600 framefunc = block_linkage_function (b);
3603 error (_("No function found for block for symbol \"%s\"."),
3604 SYMBOL_PRINT_NAME (symbol));
3606 func_get_frame_base_dwarf_block (framefunc, addr, &base_data, &base_size);
3608 if (base_data[0] >= DW_OP_breg0 && base_data[0] <= DW_OP_breg31)
3610 const gdb_byte *buf_end;
3612 frame_reg = base_data[0] - DW_OP_breg0;
3613 buf_end = safe_read_sleb128 (base_data + 1, base_data + base_size,
3615 if (buf_end != base_data + base_size)
3616 error (_("Unexpected opcode after "
3617 "DW_OP_breg%u for symbol \"%s\"."),
3618 frame_reg, SYMBOL_PRINT_NAME (symbol));
3620 else if (base_data[0] >= DW_OP_reg0 && base_data[0] <= DW_OP_reg31)
3622 /* The frame base is just the register, with no offset. */
3623 frame_reg = base_data[0] - DW_OP_reg0;
3628 /* We don't know what to do with the frame base expression,
3629 so we can't trace this variable; give up. */
3633 fprintf_filtered (stream,
3634 _("a variable at frame base reg $%s offset %s+%s"),
3635 locexpr_regname (gdbarch, frame_reg),
3636 plongest (base_offset), plongest (frame_offset));
3638 else if (data[0] >= DW_OP_breg0 && data[0] <= DW_OP_breg31
3639 && piece_end_p (data, end))
3643 data = safe_read_sleb128 (data + 1, end, &offset);
3645 fprintf_filtered (stream,
3646 _("a variable at offset %s from base reg $%s"),
3648 locexpr_regname (gdbarch, data[0] - DW_OP_breg0));
3651 /* The location expression for a TLS variable looks like this (on a
3654 DW_AT_location : 10 byte block: 3 4 0 0 0 0 0 0 0 e0
3655 (DW_OP_addr: 4; DW_OP_GNU_push_tls_address)
3657 0x3 is the encoding for DW_OP_addr, which has an operand as long
3658 as the size of an address on the target machine (here is 8
3659 bytes). Note that more recent version of GCC emit DW_OP_const4u
3660 or DW_OP_const8u, depending on address size, rather than
3661 DW_OP_addr. 0xe0 is the encoding for DW_OP_GNU_push_tls_address.
3662 The operand represents the offset at which the variable is within
3663 the thread local storage. */
3665 else if (data + 1 + addr_size < end
3666 && (data[0] == DW_OP_addr
3667 || (addr_size == 4 && data[0] == DW_OP_const4u)
3668 || (addr_size == 8 && data[0] == DW_OP_const8u))
3669 && data[1 + addr_size] == DW_OP_GNU_push_tls_address
3670 && piece_end_p (data + 2 + addr_size, end))
3673 offset = extract_unsigned_integer (data + 1, addr_size,
3674 gdbarch_byte_order (gdbarch));
3676 fprintf_filtered (stream,
3677 _("a thread-local variable at offset 0x%s "
3678 "in the thread-local storage for `%s'"),
3679 phex_nz (offset, addr_size), objfile_name (objfile));
3681 data += 1 + addr_size + 1;
3684 /* With -gsplit-dwarf a TLS variable can also look like this:
3685 DW_AT_location : 3 byte block: fc 4 e0
3686 (DW_OP_GNU_const_index: 4;
3687 DW_OP_GNU_push_tls_address) */
3688 else if (data + 3 <= end
3689 && data + 1 + (leb128_size = skip_leb128 (data + 1, end)) < end
3690 && data[0] == DW_OP_GNU_const_index
3692 && data[1 + leb128_size] == DW_OP_GNU_push_tls_address
3693 && piece_end_p (data + 2 + leb128_size, end))
3697 data = safe_read_uleb128 (data + 1, end, &offset);
3698 offset = dwarf2_read_addr_index (per_cu, offset);
3699 fprintf_filtered (stream,
3700 _("a thread-local variable at offset 0x%s "
3701 "in the thread-local storage for `%s'"),
3702 phex_nz (offset, addr_size), objfile_name (objfile));
3706 else if (data[0] >= DW_OP_lit0
3707 && data[0] <= DW_OP_lit31
3709 && data[1] == DW_OP_stack_value)
3711 fprintf_filtered (stream, _("the constant %d"), data[0] - DW_OP_lit0);
3718 /* Disassemble an expression, stopping at the end of a piece or at the
3719 end of the expression. Returns a pointer to the next unread byte
3720 in the input expression. If ALL is nonzero, then this function
3721 will keep going until it reaches the end of the expression.
3722 If there is an error during reading, e.g. we run off the end
3723 of the buffer, an error is thrown. */
3725 static const gdb_byte *
3726 disassemble_dwarf_expression (struct ui_file *stream,
3727 struct gdbarch *arch, unsigned int addr_size,
3728 int offset_size, const gdb_byte *start,
3729 const gdb_byte *data, const gdb_byte *end,
3730 int indent, int all,
3731 struct dwarf2_per_cu_data *per_cu)
3735 || (data[0] != DW_OP_piece && data[0] != DW_OP_bit_piece)))
3737 enum dwarf_location_atom op = *data++;
3742 name = get_DW_OP_name (op);
3745 error (_("Unrecognized DWARF opcode 0x%02x at %ld"),
3746 op, (long) (data - 1 - start));
3747 fprintf_filtered (stream, " %*ld: %s", indent + 4,
3748 (long) (data - 1 - start), name);
3753 ul = extract_unsigned_integer (data, addr_size,
3754 gdbarch_byte_order (arch));
3756 fprintf_filtered (stream, " 0x%s", phex_nz (ul, addr_size));
3760 ul = extract_unsigned_integer (data, 1, gdbarch_byte_order (arch));
3762 fprintf_filtered (stream, " %s", pulongest (ul));
3765 l = extract_signed_integer (data, 1, gdbarch_byte_order (arch));
3767 fprintf_filtered (stream, " %s", plongest (l));
3770 ul = extract_unsigned_integer (data, 2, gdbarch_byte_order (arch));
3772 fprintf_filtered (stream, " %s", pulongest (ul));
3775 l = extract_signed_integer (data, 2, gdbarch_byte_order (arch));
3777 fprintf_filtered (stream, " %s", plongest (l));
3780 ul = extract_unsigned_integer (data, 4, gdbarch_byte_order (arch));
3782 fprintf_filtered (stream, " %s", pulongest (ul));
3785 l = extract_signed_integer (data, 4, gdbarch_byte_order (arch));
3787 fprintf_filtered (stream, " %s", plongest (l));
3790 ul = extract_unsigned_integer (data, 8, gdbarch_byte_order (arch));
3792 fprintf_filtered (stream, " %s", pulongest (ul));
3795 l = extract_signed_integer (data, 8, gdbarch_byte_order (arch));
3797 fprintf_filtered (stream, " %s", plongest (l));
3800 data = safe_read_uleb128 (data, end, &ul);
3801 fprintf_filtered (stream, " %s", pulongest (ul));
3804 data = safe_read_sleb128 (data, end, &l);
3805 fprintf_filtered (stream, " %s", plongest (l));
3840 fprintf_filtered (stream, " [$%s]",
3841 locexpr_regname (arch, op - DW_OP_reg0));
3845 data = safe_read_uleb128 (data, end, &ul);
3846 fprintf_filtered (stream, " %s [$%s]", pulongest (ul),
3847 locexpr_regname (arch, (int) ul));
3850 case DW_OP_implicit_value:
3851 data = safe_read_uleb128 (data, end, &ul);
3853 fprintf_filtered (stream, " %s", pulongest (ul));
3888 data = safe_read_sleb128 (data, end, &l);
3889 fprintf_filtered (stream, " %s [$%s]", plongest (l),
3890 locexpr_regname (arch, op - DW_OP_breg0));
3894 data = safe_read_uleb128 (data, end, &ul);
3895 data = safe_read_sleb128 (data, end, &l);
3896 fprintf_filtered (stream, " register %s [$%s] offset %s",
3898 locexpr_regname (arch, (int) ul),
3903 data = safe_read_sleb128 (data, end, &l);
3904 fprintf_filtered (stream, " %s", plongest (l));
3907 case DW_OP_xderef_size:
3908 case DW_OP_deref_size:
3910 fprintf_filtered (stream, " %d", *data);
3914 case DW_OP_plus_uconst:
3915 data = safe_read_uleb128 (data, end, &ul);
3916 fprintf_filtered (stream, " %s", pulongest (ul));
3920 l = extract_signed_integer (data, 2, gdbarch_byte_order (arch));
3922 fprintf_filtered (stream, " to %ld",
3923 (long) (data + l - start));
3927 l = extract_signed_integer (data, 2, gdbarch_byte_order (arch));
3929 fprintf_filtered (stream, " %ld",
3930 (long) (data + l - start));
3934 ul = extract_unsigned_integer (data, 2, gdbarch_byte_order (arch));
3936 fprintf_filtered (stream, " offset %s", phex_nz (ul, 2));
3940 ul = extract_unsigned_integer (data, 4, gdbarch_byte_order (arch));
3942 fprintf_filtered (stream, " offset %s", phex_nz (ul, 4));
3945 case DW_OP_call_ref:
3946 ul = extract_unsigned_integer (data, offset_size,
3947 gdbarch_byte_order (arch));
3948 data += offset_size;
3949 fprintf_filtered (stream, " offset %s", phex_nz (ul, offset_size));
3953 data = safe_read_uleb128 (data, end, &ul);
3954 fprintf_filtered (stream, " %s (bytes)", pulongest (ul));
3957 case DW_OP_bit_piece:
3961 data = safe_read_uleb128 (data, end, &ul);
3962 data = safe_read_uleb128 (data, end, &offset);
3963 fprintf_filtered (stream, " size %s offset %s (bits)",
3964 pulongest (ul), pulongest (offset));
3968 case DW_OP_GNU_implicit_pointer:
3970 ul = extract_unsigned_integer (data, offset_size,
3971 gdbarch_byte_order (arch));
3972 data += offset_size;
3974 data = safe_read_sleb128 (data, end, &l);
3976 fprintf_filtered (stream, " DIE %s offset %s",
3977 phex_nz (ul, offset_size),
3982 case DW_OP_GNU_deref_type:
3984 int addr_size = *data++;
3988 data = safe_read_uleb128 (data, end, &ul);
3990 type = dwarf2_get_die_type (offset, per_cu);
3991 fprintf_filtered (stream, "<");
3992 type_print (type, "", stream, -1);
3993 fprintf_filtered (stream, " [0x%s]> %d", phex_nz (offset.cu_off, 0),
3998 case DW_OP_GNU_const_type:
4003 data = safe_read_uleb128 (data, end, &ul);
4004 type_die.cu_off = ul;
4005 type = dwarf2_get_die_type (type_die, per_cu);
4006 fprintf_filtered (stream, "<");
4007 type_print (type, "", stream, -1);
4008 fprintf_filtered (stream, " [0x%s]>", phex_nz (type_die.cu_off, 0));
4012 case DW_OP_GNU_regval_type:
4018 data = safe_read_uleb128 (data, end, ®);
4019 data = safe_read_uleb128 (data, end, &ul);
4020 type_die.cu_off = ul;
4022 type = dwarf2_get_die_type (type_die, per_cu);
4023 fprintf_filtered (stream, "<");
4024 type_print (type, "", stream, -1);
4025 fprintf_filtered (stream, " [0x%s]> [$%s]",
4026 phex_nz (type_die.cu_off, 0),
4027 locexpr_regname (arch, reg));
4031 case DW_OP_GNU_convert:
4032 case DW_OP_GNU_reinterpret:
4036 data = safe_read_uleb128 (data, end, &ul);
4037 type_die.cu_off = ul;
4039 if (type_die.cu_off == 0)
4040 fprintf_filtered (stream, "<0>");
4045 type = dwarf2_get_die_type (type_die, per_cu);
4046 fprintf_filtered (stream, "<");
4047 type_print (type, "", stream, -1);
4048 fprintf_filtered (stream, " [0x%s]>", phex_nz (type_die.cu_off, 0));
4053 case DW_OP_GNU_entry_value:
4054 data = safe_read_uleb128 (data, end, &ul);
4055 fputc_filtered ('\n', stream);
4056 disassemble_dwarf_expression (stream, arch, addr_size, offset_size,
4057 start, data, data + ul, indent + 2,
4062 case DW_OP_GNU_parameter_ref:
4063 ul = extract_unsigned_integer (data, 4, gdbarch_byte_order (arch));
4065 fprintf_filtered (stream, " offset %s", phex_nz (ul, 4));
4068 case DW_OP_GNU_addr_index:
4069 data = safe_read_uleb128 (data, end, &ul);
4070 ul = dwarf2_read_addr_index (per_cu, ul);
4071 fprintf_filtered (stream, " 0x%s", phex_nz (ul, addr_size));
4073 case DW_OP_GNU_const_index:
4074 data = safe_read_uleb128 (data, end, &ul);
4075 ul = dwarf2_read_addr_index (per_cu, ul);
4076 fprintf_filtered (stream, " %s", pulongest (ul));
4080 fprintf_filtered (stream, "\n");
4086 /* Describe a single location, which may in turn consist of multiple
4090 locexpr_describe_location_1 (struct symbol *symbol, CORE_ADDR addr,
4091 struct ui_file *stream,
4092 const gdb_byte *data, size_t size,
4093 struct objfile *objfile, unsigned int addr_size,
4094 int offset_size, struct dwarf2_per_cu_data *per_cu)
4096 const gdb_byte *end = data + size;
4097 int first_piece = 1, bad = 0;
4101 const gdb_byte *here = data;
4102 int disassemble = 1;
4107 fprintf_filtered (stream, _(", and "));
4109 if (!dwarf2_always_disassemble)
4111 data = locexpr_describe_location_piece (symbol, stream,
4112 addr, objfile, per_cu,
4113 data, end, addr_size);
4114 /* If we printed anything, or if we have an empty piece,
4115 then don't disassemble. */
4117 || data[0] == DW_OP_piece
4118 || data[0] == DW_OP_bit_piece)
4123 fprintf_filtered (stream, _("a complex DWARF expression:\n"));
4124 data = disassemble_dwarf_expression (stream,
4125 get_objfile_arch (objfile),
4126 addr_size, offset_size, data,
4128 dwarf2_always_disassemble,
4134 int empty = data == here;
4137 fprintf_filtered (stream, " ");
4138 if (data[0] == DW_OP_piece)
4142 data = safe_read_uleb128 (data + 1, end, &bytes);
4145 fprintf_filtered (stream, _("an empty %s-byte piece"),
4148 fprintf_filtered (stream, _(" [%s-byte piece]"),
4151 else if (data[0] == DW_OP_bit_piece)
4153 uint64_t bits, offset;
4155 data = safe_read_uleb128 (data + 1, end, &bits);
4156 data = safe_read_uleb128 (data, end, &offset);
4159 fprintf_filtered (stream,
4160 _("an empty %s-bit piece"),
4163 fprintf_filtered (stream,
4164 _(" [%s-bit piece, offset %s bits]"),
4165 pulongest (bits), pulongest (offset));
4175 if (bad || data > end)
4176 error (_("Corrupted DWARF2 expression for \"%s\"."),
4177 SYMBOL_PRINT_NAME (symbol));
4180 /* Print a natural-language description of SYMBOL to STREAM. This
4181 version is for a symbol with a single location. */
4184 locexpr_describe_location (struct symbol *symbol, CORE_ADDR addr,
4185 struct ui_file *stream)
4187 struct dwarf2_locexpr_baton *dlbaton = SYMBOL_LOCATION_BATON (symbol);
4188 struct objfile *objfile = dwarf2_per_cu_objfile (dlbaton->per_cu);
4189 unsigned int addr_size = dwarf2_per_cu_addr_size (dlbaton->per_cu);
4190 int offset_size = dwarf2_per_cu_offset_size (dlbaton->per_cu);
4192 locexpr_describe_location_1 (symbol, addr, stream,
4193 dlbaton->data, dlbaton->size,
4194 objfile, addr_size, offset_size,
4198 /* Describe the location of SYMBOL as an agent value in VALUE, generating
4199 any necessary bytecode in AX. */
4202 locexpr_tracepoint_var_ref (struct symbol *symbol, struct gdbarch *gdbarch,
4203 struct agent_expr *ax, struct axs_value *value)
4205 struct dwarf2_locexpr_baton *dlbaton = SYMBOL_LOCATION_BATON (symbol);
4206 unsigned int addr_size = dwarf2_per_cu_addr_size (dlbaton->per_cu);
4208 if (dlbaton->size == 0)
4209 value->optimized_out = 1;
4211 dwarf2_compile_expr_to_ax (ax, value, gdbarch, addr_size,
4212 dlbaton->data, dlbaton->data + dlbaton->size,
4216 /* symbol_computed_ops 'generate_c_location' method. */
4219 locexpr_generate_c_location (struct symbol *sym, struct ui_file *stream,
4220 struct gdbarch *gdbarch,
4221 unsigned char *registers_used,
4222 CORE_ADDR pc, const char *result_name)
4224 struct dwarf2_locexpr_baton *dlbaton = SYMBOL_LOCATION_BATON (sym);
4225 unsigned int addr_size = dwarf2_per_cu_addr_size (dlbaton->per_cu);
4227 if (dlbaton->size == 0)
4228 error (_("symbol \"%s\" is optimized out"), SYMBOL_NATURAL_NAME (sym));
4230 compile_dwarf_expr_to_c (stream, result_name,
4231 sym, pc, gdbarch, registers_used, addr_size,
4232 dlbaton->data, dlbaton->data + dlbaton->size,
4236 /* The set of location functions used with the DWARF-2 expression
4238 const struct symbol_computed_ops dwarf2_locexpr_funcs = {
4239 locexpr_read_variable,
4240 locexpr_read_variable_at_entry,
4241 locexpr_read_needs_frame,
4242 locexpr_describe_location,
4243 0, /* location_has_loclist */
4244 locexpr_tracepoint_var_ref,
4245 locexpr_generate_c_location
4249 /* Wrapper functions for location lists. These generally find
4250 the appropriate location expression and call something above. */
4252 /* Return the value of SYMBOL in FRAME using the DWARF-2 expression
4253 evaluator to calculate the location. */
4254 static struct value *
4255 loclist_read_variable (struct symbol *symbol, struct frame_info *frame)
4257 struct dwarf2_loclist_baton *dlbaton = SYMBOL_LOCATION_BATON (symbol);
4259 const gdb_byte *data;
4261 CORE_ADDR pc = frame ? get_frame_address_in_block (frame) : 0;
4263 data = dwarf2_find_location_expression (dlbaton, &size, pc);
4264 val = dwarf2_evaluate_loc_desc (SYMBOL_TYPE (symbol), frame, data, size,
4270 /* Read variable SYMBOL like loclist_read_variable at (callee) FRAME's function
4271 entry. SYMBOL should be a function parameter, otherwise NO_ENTRY_VALUE_ERROR
4274 Function always returns non-NULL value, it may be marked optimized out if
4275 inferior frame information is not available. It throws NO_ENTRY_VALUE_ERROR
4276 if it cannot resolve the parameter for any reason. */
4278 static struct value *
4279 loclist_read_variable_at_entry (struct symbol *symbol, struct frame_info *frame)
4281 struct dwarf2_loclist_baton *dlbaton = SYMBOL_LOCATION_BATON (symbol);
4282 const gdb_byte *data;
4286 if (frame == NULL || !get_frame_func_if_available (frame, &pc))
4287 return allocate_optimized_out_value (SYMBOL_TYPE (symbol));
4289 data = dwarf2_find_location_expression (dlbaton, &size, pc);
4291 return allocate_optimized_out_value (SYMBOL_TYPE (symbol));
4293 return value_of_dwarf_block_entry (SYMBOL_TYPE (symbol), frame, data, size);
4296 /* Return non-zero iff we need a frame to evaluate SYMBOL. */
4298 loclist_read_needs_frame (struct symbol *symbol)
4300 /* If there's a location list, then assume we need to have a frame
4301 to choose the appropriate location expression. With tracking of
4302 global variables this is not necessarily true, but such tracking
4303 is disabled in GCC at the moment until we figure out how to
4309 /* Print a natural-language description of SYMBOL to STREAM. This
4310 version applies when there is a list of different locations, each
4311 with a specified address range. */
4314 loclist_describe_location (struct symbol *symbol, CORE_ADDR addr,
4315 struct ui_file *stream)
4317 struct dwarf2_loclist_baton *dlbaton = SYMBOL_LOCATION_BATON (symbol);
4318 const gdb_byte *loc_ptr, *buf_end;
4319 struct objfile *objfile = dwarf2_per_cu_objfile (dlbaton->per_cu);
4320 struct gdbarch *gdbarch = get_objfile_arch (objfile);
4321 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
4322 unsigned int addr_size = dwarf2_per_cu_addr_size (dlbaton->per_cu);
4323 int offset_size = dwarf2_per_cu_offset_size (dlbaton->per_cu);
4324 int signed_addr_p = bfd_get_sign_extend_vma (objfile->obfd);
4325 /* Adjust base_address for relocatable objects. */
4326 CORE_ADDR base_offset = dwarf2_per_cu_text_offset (dlbaton->per_cu);
4327 CORE_ADDR base_address = dlbaton->base_address + base_offset;
4330 loc_ptr = dlbaton->data;
4331 buf_end = dlbaton->data + dlbaton->size;
4333 fprintf_filtered (stream, _("multi-location:\n"));
4335 /* Iterate through locations until we run out. */
4338 CORE_ADDR low = 0, high = 0; /* init for gcc -Wall */
4340 enum debug_loc_kind kind;
4341 const gdb_byte *new_ptr = NULL; /* init for gcc -Wall */
4343 if (dlbaton->from_dwo)
4344 kind = decode_debug_loc_dwo_addresses (dlbaton->per_cu,
4345 loc_ptr, buf_end, &new_ptr,
4346 &low, &high, byte_order);
4348 kind = decode_debug_loc_addresses (loc_ptr, buf_end, &new_ptr,
4350 byte_order, addr_size,
4355 case DEBUG_LOC_END_OF_LIST:
4358 case DEBUG_LOC_BASE_ADDRESS:
4359 base_address = high + base_offset;
4360 fprintf_filtered (stream, _(" Base address %s"),
4361 paddress (gdbarch, base_address));
4363 case DEBUG_LOC_START_END:
4364 case DEBUG_LOC_START_LENGTH:
4366 case DEBUG_LOC_BUFFER_OVERFLOW:
4367 case DEBUG_LOC_INVALID_ENTRY:
4368 error (_("Corrupted DWARF expression for symbol \"%s\"."),
4369 SYMBOL_PRINT_NAME (symbol));
4371 gdb_assert_not_reached ("bad debug_loc_kind");
4374 /* Otherwise, a location expression entry. */
4375 low += base_address;
4376 high += base_address;
4378 low = gdbarch_adjust_dwarf2_addr (gdbarch, low);
4379 high = gdbarch_adjust_dwarf2_addr (gdbarch, high);
4381 length = extract_unsigned_integer (loc_ptr, 2, byte_order);
4384 /* (It would improve readability to print only the minimum
4385 necessary digits of the second number of the range.) */
4386 fprintf_filtered (stream, _(" Range %s-%s: "),
4387 paddress (gdbarch, low), paddress (gdbarch, high));
4389 /* Now describe this particular location. */
4390 locexpr_describe_location_1 (symbol, low, stream, loc_ptr, length,
4391 objfile, addr_size, offset_size,
4394 fprintf_filtered (stream, "\n");
4400 /* Describe the location of SYMBOL as an agent value in VALUE, generating
4401 any necessary bytecode in AX. */
4403 loclist_tracepoint_var_ref (struct symbol *symbol, struct gdbarch *gdbarch,
4404 struct agent_expr *ax, struct axs_value *value)
4406 struct dwarf2_loclist_baton *dlbaton = SYMBOL_LOCATION_BATON (symbol);
4407 const gdb_byte *data;
4409 unsigned int addr_size = dwarf2_per_cu_addr_size (dlbaton->per_cu);
4411 data = dwarf2_find_location_expression (dlbaton, &size, ax->scope);
4413 value->optimized_out = 1;
4415 dwarf2_compile_expr_to_ax (ax, value, gdbarch, addr_size, data, data + size,
4419 /* symbol_computed_ops 'generate_c_location' method. */
4422 loclist_generate_c_location (struct symbol *sym, struct ui_file *stream,
4423 struct gdbarch *gdbarch,
4424 unsigned char *registers_used,
4425 CORE_ADDR pc, const char *result_name)
4427 struct dwarf2_loclist_baton *dlbaton = SYMBOL_LOCATION_BATON (sym);
4428 unsigned int addr_size = dwarf2_per_cu_addr_size (dlbaton->per_cu);
4429 const gdb_byte *data;
4432 data = dwarf2_find_location_expression (dlbaton, &size, pc);
4434 error (_("symbol \"%s\" is optimized out"), SYMBOL_NATURAL_NAME (sym));
4436 compile_dwarf_expr_to_c (stream, result_name,
4437 sym, pc, gdbarch, registers_used, addr_size,
4442 /* The set of location functions used with the DWARF-2 expression
4443 evaluator and location lists. */
4444 const struct symbol_computed_ops dwarf2_loclist_funcs = {
4445 loclist_read_variable,
4446 loclist_read_variable_at_entry,
4447 loclist_read_needs_frame,
4448 loclist_describe_location,
4449 1, /* location_has_loclist */
4450 loclist_tracepoint_var_ref,
4451 loclist_generate_c_location
4454 /* Provide a prototype to silence -Wmissing-prototypes. */
4455 extern initialize_file_ftype _initialize_dwarf2loc;
4458 _initialize_dwarf2loc (void)
4460 add_setshow_zuinteger_cmd ("entry-values", class_maintenance,
4461 &entry_values_debug,
4462 _("Set entry values and tail call frames "
4464 _("Show entry values and tail call frames "
4466 _("When non-zero, the process of determining "
4467 "parameter values from function entry point "
4468 "and tail call frames will be printed."),
4470 show_entry_values_debug,
4471 &setdebuglist, &showdebuglist);