1 /* DWARF 2 location expression support for GDB.
3 Copyright (C) 2003, 2005, 2007, 2008, 2009, 2010, 2011
4 Free Software Foundation, Inc.
6 Contributed by Daniel Jacobowitz, MontaVista Software, Inc.
8 This file is part of GDB.
10 This program is free software; you can redistribute it and/or modify
11 it under the terms of the GNU General Public License as published by
12 the Free Software Foundation; either version 3 of the License, or
13 (at your option) any later version.
15 This program is distributed in the hope that it will be useful,
16 but WITHOUT ANY WARRANTY; without even the implied warranty of
17 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 GNU General Public License for more details.
20 You should have received a copy of the GNU General Public License
21 along with this program. If not, see <http://www.gnu.org/licenses/>. */
34 #include "exceptions.h"
38 #include "dwarf2expr.h"
39 #include "dwarf2loc.h"
40 #include "dwarf2-frame.h"
42 #include "gdb_string.h"
43 #include "gdb_assert.h"
45 extern int dwarf2_always_disassemble;
47 static void dwarf_expr_frame_base_1 (struct symbol *framefunc, CORE_ADDR pc,
48 const gdb_byte **start, size_t *length);
50 static struct value *dwarf2_evaluate_loc_desc_full (struct type *type,
51 struct frame_info *frame,
54 struct dwarf2_per_cu_data *per_cu,
57 /* A function for dealing with location lists. Given a
58 symbol baton (BATON) and a pc value (PC), find the appropriate
59 location expression, set *LOCEXPR_LENGTH, and return a pointer
60 to the beginning of the expression. Returns NULL on failure.
62 For now, only return the first matching location expression; there
63 can be more than one in the list. */
66 dwarf2_find_location_expression (struct dwarf2_loclist_baton *baton,
67 size_t *locexpr_length, CORE_ADDR pc)
70 const gdb_byte *loc_ptr, *buf_end;
72 struct objfile *objfile = dwarf2_per_cu_objfile (baton->per_cu);
73 struct gdbarch *gdbarch = get_objfile_arch (objfile);
74 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
75 unsigned int addr_size = dwarf2_per_cu_addr_size (baton->per_cu);
76 int signed_addr_p = bfd_get_sign_extend_vma (objfile->obfd);
77 CORE_ADDR base_mask = ~(~(CORE_ADDR)1 << (addr_size * 8 - 1));
78 /* Adjust base_address for relocatable objects. */
79 CORE_ADDR base_offset = dwarf2_per_cu_text_offset (baton->per_cu);
80 CORE_ADDR base_address = baton->base_address + base_offset;
82 loc_ptr = baton->data;
83 buf_end = baton->data + baton->size;
87 if (buf_end - loc_ptr < 2 * addr_size)
88 error (_("dwarf2_find_location_expression: "
89 "Corrupted DWARF expression."));
92 low = extract_signed_integer (loc_ptr, addr_size, byte_order);
94 low = extract_unsigned_integer (loc_ptr, addr_size, byte_order);
98 high = extract_signed_integer (loc_ptr, addr_size, byte_order);
100 high = extract_unsigned_integer (loc_ptr, addr_size, byte_order);
101 loc_ptr += addr_size;
103 /* A base-address-selection entry. */
104 if ((low & base_mask) == base_mask)
106 base_address = high + base_offset;
110 /* An end-of-list entry. */
111 if (low == 0 && high == 0)
114 /* Otherwise, a location expression entry. */
116 high += base_address;
118 length = extract_unsigned_integer (loc_ptr, 2, byte_order);
121 if (pc >= low && pc < high)
123 *locexpr_length = length;
131 /* This is the baton used when performing dwarf2 expression
133 struct dwarf_expr_baton
135 struct frame_info *frame;
136 struct dwarf2_per_cu_data *per_cu;
139 /* Helper functions for dwarf2_evaluate_loc_desc. */
141 /* Using the frame specified in BATON, return the value of register
142 REGNUM, treated as a pointer. */
144 dwarf_expr_read_reg (void *baton, int dwarf_regnum)
146 struct dwarf_expr_baton *debaton = (struct dwarf_expr_baton *) baton;
147 struct gdbarch *gdbarch = get_frame_arch (debaton->frame);
151 regnum = gdbarch_dwarf2_reg_to_regnum (gdbarch, dwarf_regnum);
152 result = address_from_register (builtin_type (gdbarch)->builtin_data_ptr,
153 regnum, debaton->frame);
157 /* Read memory at ADDR (length LEN) into BUF. */
160 dwarf_expr_read_mem (void *baton, gdb_byte *buf, CORE_ADDR addr, size_t len)
162 read_memory (addr, buf, len);
165 /* Using the frame specified in BATON, find the location expression
166 describing the frame base. Return a pointer to it in START and
167 its length in LENGTH. */
169 dwarf_expr_frame_base (void *baton, const gdb_byte **start, size_t * length)
171 /* FIXME: cagney/2003-03-26: This code should be using
172 get_frame_base_address(), and then implement a dwarf2 specific
174 struct symbol *framefunc;
175 struct dwarf_expr_baton *debaton = (struct dwarf_expr_baton *) baton;
177 /* Use block_linkage_function, which returns a real (not inlined)
178 function, instead of get_frame_function, which may return an
180 framefunc = block_linkage_function (get_frame_block (debaton->frame, NULL));
182 /* If we found a frame-relative symbol then it was certainly within
183 some function associated with a frame. If we can't find the frame,
184 something has gone wrong. */
185 gdb_assert (framefunc != NULL);
187 dwarf_expr_frame_base_1 (framefunc,
188 get_frame_address_in_block (debaton->frame),
193 dwarf_expr_frame_base_1 (struct symbol *framefunc, CORE_ADDR pc,
194 const gdb_byte **start, size_t *length)
196 if (SYMBOL_LOCATION_BATON (framefunc) == NULL)
198 else if (SYMBOL_COMPUTED_OPS (framefunc) == &dwarf2_loclist_funcs)
200 struct dwarf2_loclist_baton *symbaton;
202 symbaton = SYMBOL_LOCATION_BATON (framefunc);
203 *start = dwarf2_find_location_expression (symbaton, length, pc);
207 struct dwarf2_locexpr_baton *symbaton;
209 symbaton = SYMBOL_LOCATION_BATON (framefunc);
210 if (symbaton != NULL)
212 *length = symbaton->size;
213 *start = symbaton->data;
220 error (_("Could not find the frame base for \"%s\"."),
221 SYMBOL_NATURAL_NAME (framefunc));
224 /* Helper function for dwarf2_evaluate_loc_desc. Computes the CFA for
225 the frame in BATON. */
228 dwarf_expr_frame_cfa (void *baton)
230 struct dwarf_expr_baton *debaton = (struct dwarf_expr_baton *) baton;
232 return dwarf2_frame_cfa (debaton->frame);
235 /* Helper function for dwarf2_evaluate_loc_desc. Computes the PC for
236 the frame in BATON. */
239 dwarf_expr_frame_pc (void *baton)
241 struct dwarf_expr_baton *debaton = (struct dwarf_expr_baton *) baton;
243 return get_frame_address_in_block (debaton->frame);
246 /* Using the objfile specified in BATON, find the address for the
247 current thread's thread-local storage with offset OFFSET. */
249 dwarf_expr_tls_address (void *baton, CORE_ADDR offset)
251 struct dwarf_expr_baton *debaton = (struct dwarf_expr_baton *) baton;
252 struct objfile *objfile = dwarf2_per_cu_objfile (debaton->per_cu);
254 return target_translate_tls_address (objfile, offset);
257 /* Call DWARF subroutine from DW_AT_location of DIE at DIE_OFFSET in
258 current CU (as is PER_CU). State of the CTX is not affected by the
262 per_cu_dwarf_call (struct dwarf_expr_context *ctx, size_t die_offset,
263 struct dwarf2_per_cu_data *per_cu,
264 CORE_ADDR (*get_frame_pc) (void *baton),
267 struct dwarf2_locexpr_baton block;
268 struct cleanup *back_to;
270 block = dwarf2_fetch_die_location_block (die_offset, per_cu,
271 get_frame_pc, baton);
273 back_to = make_cleanup (xfree, (void *) block.data);
275 /* DW_OP_call_ref is currently not supported. */
276 gdb_assert (block.per_cu == per_cu);
278 dwarf_expr_eval (ctx, block.data, block.size);
280 do_cleanups (back_to);
283 /* Helper interface of per_cu_dwarf_call for dwarf2_evaluate_loc_desc. */
286 dwarf_expr_dwarf_call (struct dwarf_expr_context *ctx, size_t die_offset)
288 struct dwarf_expr_baton *debaton = ctx->baton;
290 per_cu_dwarf_call (ctx, die_offset, debaton->per_cu,
291 ctx->funcs->get_frame_pc, ctx->baton);
294 /* Callback function for dwarf2_evaluate_loc_desc. */
297 dwarf_expr_get_base_type (struct dwarf_expr_context *ctx, size_t die_offset)
299 struct dwarf_expr_baton *debaton = ctx->baton;
301 return dwarf2_get_die_type (die_offset, debaton->per_cu);
306 /* Reference count. */
309 /* The CU from which this closure's expression came. */
310 struct dwarf2_per_cu_data *per_cu;
312 /* The number of pieces used to describe this variable. */
315 /* The target address size, used only for DWARF_VALUE_STACK. */
318 /* The pieces themselves. */
319 struct dwarf_expr_piece *pieces;
322 /* Allocate a closure for a value formed from separately-described
325 static struct piece_closure *
326 allocate_piece_closure (struct dwarf2_per_cu_data *per_cu,
327 int n_pieces, struct dwarf_expr_piece *pieces,
330 struct piece_closure *c = XZALLOC (struct piece_closure);
335 c->n_pieces = n_pieces;
336 c->addr_size = addr_size;
337 c->pieces = XCALLOC (n_pieces, struct dwarf_expr_piece);
339 memcpy (c->pieces, pieces, n_pieces * sizeof (struct dwarf_expr_piece));
340 for (i = 0; i < n_pieces; ++i)
341 if (c->pieces[i].location == DWARF_VALUE_STACK)
342 value_incref (c->pieces[i].v.value);
347 /* The lowest-level function to extract bits from a byte buffer.
348 SOURCE is the buffer. It is updated if we read to the end of a
350 SOURCE_OFFSET_BITS is the offset of the first bit to read. It is
351 updated to reflect the number of bits actually read.
352 NBITS is the number of bits we want to read. It is updated to
353 reflect the number of bits actually read. This function may read
355 BITS_BIG_ENDIAN is taken directly from gdbarch.
356 This function returns the extracted bits. */
359 extract_bits_primitive (const gdb_byte **source,
360 unsigned int *source_offset_bits,
361 int *nbits, int bits_big_endian)
363 unsigned int avail, mask, datum;
365 gdb_assert (*source_offset_bits < 8);
367 avail = 8 - *source_offset_bits;
371 mask = (1 << avail) - 1;
374 datum >>= 8 - (*source_offset_bits + *nbits);
376 datum >>= *source_offset_bits;
380 *source_offset_bits += avail;
381 if (*source_offset_bits >= 8)
383 *source_offset_bits -= 8;
390 /* Extract some bits from a source buffer and move forward in the
393 SOURCE is the source buffer. It is updated as bytes are read.
394 SOURCE_OFFSET_BITS is the offset into SOURCE. It is updated as
396 NBITS is the number of bits to read.
397 BITS_BIG_ENDIAN is taken directly from gdbarch.
399 This function returns the bits that were read. */
402 extract_bits (const gdb_byte **source, unsigned int *source_offset_bits,
403 int nbits, int bits_big_endian)
407 gdb_assert (nbits > 0 && nbits <= 8);
409 datum = extract_bits_primitive (source, source_offset_bits, &nbits,
415 more = extract_bits_primitive (source, source_offset_bits, &nbits,
427 /* Write some bits into a buffer and move forward in the buffer.
429 DATUM is the bits to write. The low-order bits of DATUM are used.
430 DEST is the destination buffer. It is updated as bytes are
432 DEST_OFFSET_BITS is the bit offset in DEST at which writing is
434 NBITS is the number of valid bits in DATUM.
435 BITS_BIG_ENDIAN is taken directly from gdbarch. */
438 insert_bits (unsigned int datum,
439 gdb_byte *dest, unsigned int dest_offset_bits,
440 int nbits, int bits_big_endian)
444 gdb_assert (dest_offset_bits + nbits <= 8);
446 mask = (1 << nbits) - 1;
449 datum <<= 8 - (dest_offset_bits + nbits);
450 mask <<= 8 - (dest_offset_bits + nbits);
454 datum <<= dest_offset_bits;
455 mask <<= dest_offset_bits;
458 gdb_assert ((datum & ~mask) == 0);
460 *dest = (*dest & ~mask) | datum;
463 /* Copy bits from a source to a destination.
465 DEST is where the bits should be written.
466 DEST_OFFSET_BITS is the bit offset into DEST.
467 SOURCE is the source of bits.
468 SOURCE_OFFSET_BITS is the bit offset into SOURCE.
469 BIT_COUNT is the number of bits to copy.
470 BITS_BIG_ENDIAN is taken directly from gdbarch. */
473 copy_bitwise (gdb_byte *dest, unsigned int dest_offset_bits,
474 const gdb_byte *source, unsigned int source_offset_bits,
475 unsigned int bit_count,
478 unsigned int dest_avail;
481 /* Reduce everything to byte-size pieces. */
482 dest += dest_offset_bits / 8;
483 dest_offset_bits %= 8;
484 source += source_offset_bits / 8;
485 source_offset_bits %= 8;
487 dest_avail = 8 - dest_offset_bits % 8;
489 /* See if we can fill the first destination byte. */
490 if (dest_avail < bit_count)
492 datum = extract_bits (&source, &source_offset_bits, dest_avail,
494 insert_bits (datum, dest, dest_offset_bits, dest_avail, bits_big_endian);
496 dest_offset_bits = 0;
497 bit_count -= dest_avail;
500 /* Now, either DEST_OFFSET_BITS is byte-aligned, or we have fewer
501 than 8 bits remaining. */
502 gdb_assert (dest_offset_bits % 8 == 0 || bit_count < 8);
503 for (; bit_count >= 8; bit_count -= 8)
505 datum = extract_bits (&source, &source_offset_bits, 8, bits_big_endian);
506 *dest++ = (gdb_byte) datum;
509 /* Finally, we may have a few leftover bits. */
510 gdb_assert (bit_count <= 8 - dest_offset_bits % 8);
513 datum = extract_bits (&source, &source_offset_bits, bit_count,
515 insert_bits (datum, dest, dest_offset_bits, bit_count, bits_big_endian);
520 read_pieced_value (struct value *v)
524 ULONGEST bits_to_skip;
526 struct piece_closure *c
527 = (struct piece_closure *) value_computed_closure (v);
528 struct frame_info *frame = frame_find_by_id (VALUE_FRAME_ID (v));
530 size_t buffer_size = 0;
532 struct cleanup *cleanup;
534 = gdbarch_bits_big_endian (get_type_arch (value_type (v)));
536 if (value_type (v) != value_enclosing_type (v))
537 internal_error (__FILE__, __LINE__,
538 _("Should not be able to create a lazy value with "
539 "an enclosing type"));
541 cleanup = make_cleanup (free_current_contents, &buffer);
543 contents = value_contents_raw (v);
544 bits_to_skip = 8 * value_offset (v);
545 if (value_bitsize (v))
547 bits_to_skip += value_bitpos (v);
548 type_len = value_bitsize (v);
551 type_len = 8 * TYPE_LENGTH (value_type (v));
553 for (i = 0; i < c->n_pieces && offset < type_len; i++)
555 struct dwarf_expr_piece *p = &c->pieces[i];
556 size_t this_size, this_size_bits;
557 long dest_offset_bits, source_offset_bits, source_offset;
558 const gdb_byte *intermediate_buffer;
560 /* Compute size, source, and destination offsets for copying, in
562 this_size_bits = p->size;
563 if (bits_to_skip > 0 && bits_to_skip >= this_size_bits)
565 bits_to_skip -= this_size_bits;
568 if (this_size_bits > type_len - offset)
569 this_size_bits = type_len - offset;
570 if (bits_to_skip > 0)
572 dest_offset_bits = 0;
573 source_offset_bits = bits_to_skip;
574 this_size_bits -= bits_to_skip;
579 dest_offset_bits = offset;
580 source_offset_bits = 0;
583 this_size = (this_size_bits + source_offset_bits % 8 + 7) / 8;
584 source_offset = source_offset_bits / 8;
585 if (buffer_size < this_size)
587 buffer_size = this_size;
588 buffer = xrealloc (buffer, buffer_size);
590 intermediate_buffer = buffer;
592 /* Copy from the source to DEST_BUFFER. */
595 case DWARF_VALUE_REGISTER:
597 struct gdbarch *arch = get_frame_arch (frame);
598 int gdb_regnum = gdbarch_dwarf2_reg_to_regnum (arch, p->v.regno);
599 int reg_offset = source_offset;
601 if (gdbarch_byte_order (arch) == BFD_ENDIAN_BIG
602 && this_size < register_size (arch, gdb_regnum))
604 /* Big-endian, and we want less than full size. */
605 reg_offset = register_size (arch, gdb_regnum) - this_size;
606 /* We want the lower-order THIS_SIZE_BITS of the bytes
607 we extract from the register. */
608 source_offset_bits += 8 * this_size - this_size_bits;
611 if (gdb_regnum != -1)
615 if (!get_frame_register_bytes (frame, gdb_regnum, reg_offset,
619 /* Just so garbage doesn't ever shine through. */
620 memset (buffer, 0, this_size);
623 set_value_optimized_out (v, 1);
625 mark_value_bytes_unavailable (v, offset, this_size);
630 error (_("Unable to access DWARF register number %s"),
631 paddress (arch, p->v.regno));
636 case DWARF_VALUE_MEMORY:
637 read_value_memory (v, offset,
638 p->v.mem.in_stack_memory,
639 p->v.mem.addr + source_offset,
643 case DWARF_VALUE_STACK:
645 size_t n = this_size;
647 if (n > c->addr_size - source_offset)
648 n = (c->addr_size >= source_offset
649 ? c->addr_size - source_offset
657 const gdb_byte *val_bytes = value_contents_all (p->v.value);
659 intermediate_buffer = val_bytes + source_offset;
664 case DWARF_VALUE_LITERAL:
666 size_t n = this_size;
668 if (n > p->v.literal.length - source_offset)
669 n = (p->v.literal.length >= source_offset
670 ? p->v.literal.length - source_offset
673 intermediate_buffer = p->v.literal.data + source_offset;
677 /* These bits show up as zeros -- but do not cause the value
678 to be considered optimized-out. */
679 case DWARF_VALUE_IMPLICIT_POINTER:
682 case DWARF_VALUE_OPTIMIZED_OUT:
683 set_value_optimized_out (v, 1);
687 internal_error (__FILE__, __LINE__, _("invalid location type"));
690 if (p->location != DWARF_VALUE_OPTIMIZED_OUT
691 && p->location != DWARF_VALUE_IMPLICIT_POINTER)
692 copy_bitwise (contents, dest_offset_bits,
693 intermediate_buffer, source_offset_bits % 8,
694 this_size_bits, bits_big_endian);
696 offset += this_size_bits;
699 do_cleanups (cleanup);
703 write_pieced_value (struct value *to, struct value *from)
707 ULONGEST bits_to_skip;
708 const gdb_byte *contents;
709 struct piece_closure *c
710 = (struct piece_closure *) value_computed_closure (to);
711 struct frame_info *frame = frame_find_by_id (VALUE_FRAME_ID (to));
713 size_t buffer_size = 0;
715 struct cleanup *cleanup;
717 = gdbarch_bits_big_endian (get_type_arch (value_type (to)));
721 set_value_optimized_out (to, 1);
725 cleanup = make_cleanup (free_current_contents, &buffer);
727 contents = value_contents (from);
728 bits_to_skip = 8 * value_offset (to);
729 if (value_bitsize (to))
731 bits_to_skip += value_bitpos (to);
732 type_len = value_bitsize (to);
735 type_len = 8 * TYPE_LENGTH (value_type (to));
737 for (i = 0; i < c->n_pieces && offset < type_len; i++)
739 struct dwarf_expr_piece *p = &c->pieces[i];
740 size_t this_size_bits, this_size;
741 long dest_offset_bits, source_offset_bits, dest_offset, source_offset;
743 const gdb_byte *source_buffer;
745 this_size_bits = p->size;
746 if (bits_to_skip > 0 && bits_to_skip >= this_size_bits)
748 bits_to_skip -= this_size_bits;
751 if (this_size_bits > type_len - offset)
752 this_size_bits = type_len - offset;
753 if (bits_to_skip > 0)
755 dest_offset_bits = bits_to_skip;
756 source_offset_bits = 0;
757 this_size_bits -= bits_to_skip;
762 dest_offset_bits = 0;
763 source_offset_bits = offset;
766 this_size = (this_size_bits + source_offset_bits % 8 + 7) / 8;
767 source_offset = source_offset_bits / 8;
768 dest_offset = dest_offset_bits / 8;
769 if (dest_offset_bits % 8 == 0 && source_offset_bits % 8 == 0)
771 source_buffer = contents + source_offset;
776 if (buffer_size < this_size)
778 buffer_size = this_size;
779 buffer = xrealloc (buffer, buffer_size);
781 source_buffer = buffer;
787 case DWARF_VALUE_REGISTER:
789 struct gdbarch *arch = get_frame_arch (frame);
790 int gdb_regnum = gdbarch_dwarf2_reg_to_regnum (arch, p->v.regno);
791 int reg_offset = dest_offset;
793 if (gdbarch_byte_order (arch) == BFD_ENDIAN_BIG
794 && this_size <= register_size (arch, gdb_regnum))
795 /* Big-endian, and we want less than full size. */
796 reg_offset = register_size (arch, gdb_regnum) - this_size;
798 if (gdb_regnum != -1)
804 if (!get_frame_register_bytes (frame, gdb_regnum, reg_offset,
809 error (_("Can't do read-modify-write to "
810 "update bitfield; containing word has been "
813 throw_error (NOT_AVAILABLE_ERROR,
814 _("Can't do read-modify-write to update "
815 "bitfield; containing word "
818 copy_bitwise (buffer, dest_offset_bits,
819 contents, source_offset_bits,
824 put_frame_register_bytes (frame, gdb_regnum, reg_offset,
825 this_size, source_buffer);
829 error (_("Unable to write to DWARF register number %s"),
830 paddress (arch, p->v.regno));
834 case DWARF_VALUE_MEMORY:
837 /* Only the first and last bytes can possibly have any
839 read_memory (p->v.mem.addr + dest_offset, buffer, 1);
840 read_memory (p->v.mem.addr + dest_offset + this_size - 1,
841 buffer + this_size - 1, 1);
842 copy_bitwise (buffer, dest_offset_bits,
843 contents, source_offset_bits,
848 write_memory (p->v.mem.addr + dest_offset,
849 source_buffer, this_size);
852 set_value_optimized_out (to, 1);
855 offset += this_size_bits;
858 do_cleanups (cleanup);
861 /* A helper function that checks bit validity in a pieced value.
862 CHECK_FOR indicates the kind of validity checking.
863 DWARF_VALUE_MEMORY means to check whether any bit is valid.
864 DWARF_VALUE_OPTIMIZED_OUT means to check whether any bit is
866 DWARF_VALUE_IMPLICIT_POINTER means to check whether the bits are an
870 check_pieced_value_bits (const struct value *value, int bit_offset,
872 enum dwarf_value_location check_for)
874 struct piece_closure *c
875 = (struct piece_closure *) value_computed_closure (value);
877 int validity = (check_for == DWARF_VALUE_MEMORY
878 || check_for == DWARF_VALUE_IMPLICIT_POINTER);
880 bit_offset += 8 * value_offset (value);
881 if (value_bitsize (value))
882 bit_offset += value_bitpos (value);
884 for (i = 0; i < c->n_pieces && bit_length > 0; i++)
886 struct dwarf_expr_piece *p = &c->pieces[i];
887 size_t this_size_bits = p->size;
891 if (bit_offset >= this_size_bits)
893 bit_offset -= this_size_bits;
897 bit_length -= this_size_bits - bit_offset;
901 bit_length -= this_size_bits;
903 if (check_for == DWARF_VALUE_IMPLICIT_POINTER)
905 if (p->location != DWARF_VALUE_IMPLICIT_POINTER)
908 else if (p->location == DWARF_VALUE_OPTIMIZED_OUT
909 || p->location == DWARF_VALUE_IMPLICIT_POINTER)
925 check_pieced_value_validity (const struct value *value, int bit_offset,
928 return check_pieced_value_bits (value, bit_offset, bit_length,
933 check_pieced_value_invalid (const struct value *value)
935 return check_pieced_value_bits (value, 0,
936 8 * TYPE_LENGTH (value_type (value)),
937 DWARF_VALUE_OPTIMIZED_OUT);
940 /* An implementation of an lval_funcs method to see whether a value is
941 a synthetic pointer. */
944 check_pieced_synthetic_pointer (const struct value *value, int bit_offset,
947 return check_pieced_value_bits (value, bit_offset, bit_length,
948 DWARF_VALUE_IMPLICIT_POINTER);
951 /* A wrapper function for get_frame_address_in_block. */
954 get_frame_address_in_block_wrapper (void *baton)
956 return get_frame_address_in_block (baton);
959 /* An implementation of an lval_funcs method to indirect through a
960 pointer. This handles the synthetic pointer case when needed. */
962 static struct value *
963 indirect_pieced_value (struct value *value)
965 struct piece_closure *c
966 = (struct piece_closure *) value_computed_closure (value);
968 struct frame_info *frame;
969 struct dwarf2_locexpr_baton baton;
970 int i, bit_offset, bit_length;
971 struct dwarf_expr_piece *piece = NULL;
972 struct value *result;
974 struct cleanup *back_to;
976 type = check_typedef (value_type (value));
977 if (TYPE_CODE (type) != TYPE_CODE_PTR)
980 bit_length = 8 * TYPE_LENGTH (type);
981 bit_offset = 8 * value_offset (value);
982 if (value_bitsize (value))
983 bit_offset += value_bitpos (value);
985 for (i = 0; i < c->n_pieces && bit_length > 0; i++)
987 struct dwarf_expr_piece *p = &c->pieces[i];
988 size_t this_size_bits = p->size;
992 if (bit_offset >= this_size_bits)
994 bit_offset -= this_size_bits;
998 bit_length -= this_size_bits - bit_offset;
1002 bit_length -= this_size_bits;
1004 if (p->location != DWARF_VALUE_IMPLICIT_POINTER)
1007 if (bit_length != 0)
1008 error (_("Invalid use of DW_OP_GNU_implicit_pointer"));
1014 frame = get_selected_frame (_("No frame selected."));
1016 /* This is an offset requested by GDB, such as value subcripts. */
1017 byte_offset = value_as_address (value);
1020 baton = dwarf2_fetch_die_location_block (piece->v.ptr.die, c->per_cu,
1021 get_frame_address_in_block_wrapper,
1024 back_to = make_cleanup (xfree, (void *) baton.data);
1026 result = dwarf2_evaluate_loc_desc_full (TYPE_TARGET_TYPE (type), frame,
1027 baton.data, baton.size, baton.per_cu,
1028 piece->v.ptr.offset + byte_offset);
1030 do_cleanups (back_to);
1036 copy_pieced_value_closure (const struct value *v)
1038 struct piece_closure *c
1039 = (struct piece_closure *) value_computed_closure (v);
1046 free_pieced_value_closure (struct value *v)
1048 struct piece_closure *c
1049 = (struct piece_closure *) value_computed_closure (v);
1056 for (i = 0; i < c->n_pieces; ++i)
1057 if (c->pieces[i].location == DWARF_VALUE_STACK)
1058 value_free (c->pieces[i].v.value);
1065 /* Functions for accessing a variable described by DW_OP_piece. */
1066 static const struct lval_funcs pieced_value_funcs = {
1069 check_pieced_value_validity,
1070 check_pieced_value_invalid,
1071 indirect_pieced_value,
1072 check_pieced_synthetic_pointer,
1073 copy_pieced_value_closure,
1074 free_pieced_value_closure
1077 /* Helper function which throws an error if a synthetic pointer is
1081 invalid_synthetic_pointer (void)
1083 error (_("access outside bounds of object "
1084 "referenced via synthetic pointer"));
1087 /* Virtual method table for dwarf2_evaluate_loc_desc_full below. */
1089 static const struct dwarf_expr_context_funcs dwarf_expr_ctx_funcs =
1091 dwarf_expr_read_reg,
1092 dwarf_expr_read_mem,
1093 dwarf_expr_frame_base,
1094 dwarf_expr_frame_cfa,
1095 dwarf_expr_frame_pc,
1096 dwarf_expr_tls_address,
1097 dwarf_expr_dwarf_call,
1098 dwarf_expr_get_base_type
1101 /* Evaluate a location description, starting at DATA and with length
1102 SIZE, to find the current location of variable of TYPE in the
1103 context of FRAME. BYTE_OFFSET is applied after the contents are
1106 static struct value *
1107 dwarf2_evaluate_loc_desc_full (struct type *type, struct frame_info *frame,
1108 const gdb_byte *data, unsigned short size,
1109 struct dwarf2_per_cu_data *per_cu,
1110 LONGEST byte_offset)
1112 struct value *retval;
1113 struct dwarf_expr_baton baton;
1114 struct dwarf_expr_context *ctx;
1115 struct cleanup *old_chain, *value_chain;
1116 struct objfile *objfile = dwarf2_per_cu_objfile (per_cu);
1117 volatile struct gdb_exception ex;
1119 if (byte_offset < 0)
1120 invalid_synthetic_pointer ();
1123 return allocate_optimized_out_value (type);
1125 baton.frame = frame;
1126 baton.per_cu = per_cu;
1128 ctx = new_dwarf_expr_context ();
1129 old_chain = make_cleanup_free_dwarf_expr_context (ctx);
1130 value_chain = make_cleanup_value_free_to_mark (value_mark ());
1132 ctx->gdbarch = get_objfile_arch (objfile);
1133 ctx->addr_size = dwarf2_per_cu_addr_size (per_cu);
1134 ctx->offset = dwarf2_per_cu_text_offset (per_cu);
1135 ctx->baton = &baton;
1136 ctx->funcs = &dwarf_expr_ctx_funcs;
1138 TRY_CATCH (ex, RETURN_MASK_ERROR)
1140 dwarf_expr_eval (ctx, data, size);
1144 if (ex.error == NOT_AVAILABLE_ERROR)
1146 do_cleanups (old_chain);
1147 retval = allocate_value (type);
1148 mark_value_bytes_unavailable (retval, 0, TYPE_LENGTH (type));
1152 throw_exception (ex);
1155 if (ctx->num_pieces > 0)
1157 struct piece_closure *c;
1158 struct frame_id frame_id = get_frame_id (frame);
1159 ULONGEST bit_size = 0;
1162 for (i = 0; i < ctx->num_pieces; ++i)
1163 bit_size += ctx->pieces[i].size;
1164 if (8 * (byte_offset + TYPE_LENGTH (type)) > bit_size)
1165 invalid_synthetic_pointer ();
1167 c = allocate_piece_closure (per_cu, ctx->num_pieces, ctx->pieces,
1169 /* We must clean up the value chain after creating the piece
1170 closure but before allocating the result. */
1171 do_cleanups (value_chain);
1172 retval = allocate_computed_value (type, &pieced_value_funcs, c);
1173 VALUE_FRAME_ID (retval) = frame_id;
1174 set_value_offset (retval, byte_offset);
1178 switch (ctx->location)
1180 case DWARF_VALUE_REGISTER:
1182 struct gdbarch *arch = get_frame_arch (frame);
1183 ULONGEST dwarf_regnum = value_as_long (dwarf_expr_fetch (ctx, 0));
1184 int gdb_regnum = gdbarch_dwarf2_reg_to_regnum (arch, dwarf_regnum);
1186 if (byte_offset != 0)
1187 error (_("cannot use offset on synthetic pointer to register"));
1188 do_cleanups (value_chain);
1189 if (gdb_regnum != -1)
1190 retval = value_from_register (type, gdb_regnum, frame);
1192 error (_("Unable to access DWARF register number %s"),
1193 paddress (arch, dwarf_regnum));
1197 case DWARF_VALUE_MEMORY:
1199 CORE_ADDR address = dwarf_expr_fetch_address (ctx, 0);
1200 int in_stack_memory = dwarf_expr_fetch_in_stack_memory (ctx, 0);
1202 do_cleanups (value_chain);
1203 retval = allocate_value_lazy (type);
1204 VALUE_LVAL (retval) = lval_memory;
1205 if (in_stack_memory)
1206 set_value_stack (retval, 1);
1207 set_value_address (retval, address + byte_offset);
1211 case DWARF_VALUE_STACK:
1213 struct value *value = dwarf_expr_fetch (ctx, 0);
1215 const gdb_byte *val_bytes;
1216 size_t n = TYPE_LENGTH (value_type (value));
1218 if (byte_offset + TYPE_LENGTH (type) > n)
1219 invalid_synthetic_pointer ();
1221 val_bytes = value_contents_all (value);
1222 val_bytes += byte_offset;
1225 /* Preserve VALUE because we are going to free values back
1226 to the mark, but we still need the value contents
1228 value_incref (value);
1229 do_cleanups (value_chain);
1230 make_cleanup_value_free (value);
1232 retval = allocate_value (type);
1233 contents = value_contents_raw (retval);
1234 if (n > TYPE_LENGTH (type))
1236 struct gdbarch *objfile_gdbarch = get_objfile_arch (objfile);
1238 if (gdbarch_byte_order (objfile_gdbarch) == BFD_ENDIAN_BIG)
1239 val_bytes += n - TYPE_LENGTH (type);
1240 n = TYPE_LENGTH (type);
1242 memcpy (contents, val_bytes, n);
1246 case DWARF_VALUE_LITERAL:
1249 const bfd_byte *ldata;
1250 size_t n = ctx->len;
1252 if (byte_offset + TYPE_LENGTH (type) > n)
1253 invalid_synthetic_pointer ();
1255 do_cleanups (value_chain);
1256 retval = allocate_value (type);
1257 contents = value_contents_raw (retval);
1259 ldata = ctx->data + byte_offset;
1262 if (n > TYPE_LENGTH (type))
1264 struct gdbarch *objfile_gdbarch = get_objfile_arch (objfile);
1266 if (gdbarch_byte_order (objfile_gdbarch) == BFD_ENDIAN_BIG)
1267 ldata += n - TYPE_LENGTH (type);
1268 n = TYPE_LENGTH (type);
1270 memcpy (contents, ldata, n);
1274 case DWARF_VALUE_OPTIMIZED_OUT:
1275 do_cleanups (value_chain);
1276 retval = allocate_optimized_out_value (type);
1279 /* DWARF_VALUE_IMPLICIT_POINTER was converted to a pieced
1280 operation by execute_stack_op. */
1281 case DWARF_VALUE_IMPLICIT_POINTER:
1282 /* DWARF_VALUE_OPTIMIZED_OUT can't occur in this context --
1283 it can only be encountered when making a piece. */
1285 internal_error (__FILE__, __LINE__, _("invalid location type"));
1289 set_value_initialized (retval, ctx->initialized);
1291 do_cleanups (old_chain);
1296 /* The exported interface to dwarf2_evaluate_loc_desc_full; it always
1297 passes 0 as the byte_offset. */
1300 dwarf2_evaluate_loc_desc (struct type *type, struct frame_info *frame,
1301 const gdb_byte *data, unsigned short size,
1302 struct dwarf2_per_cu_data *per_cu)
1304 return dwarf2_evaluate_loc_desc_full (type, frame, data, size, per_cu, 0);
1308 /* Helper functions and baton for dwarf2_loc_desc_needs_frame. */
1310 struct needs_frame_baton
1313 struct dwarf2_per_cu_data *per_cu;
1316 /* Reads from registers do require a frame. */
1318 needs_frame_read_reg (void *baton, int regnum)
1320 struct needs_frame_baton *nf_baton = baton;
1322 nf_baton->needs_frame = 1;
1326 /* Reads from memory do not require a frame. */
1328 needs_frame_read_mem (void *baton, gdb_byte *buf, CORE_ADDR addr, size_t len)
1330 memset (buf, 0, len);
1333 /* Frame-relative accesses do require a frame. */
1335 needs_frame_frame_base (void *baton, const gdb_byte **start, size_t * length)
1337 static gdb_byte lit0 = DW_OP_lit0;
1338 struct needs_frame_baton *nf_baton = baton;
1343 nf_baton->needs_frame = 1;
1346 /* CFA accesses require a frame. */
1349 needs_frame_frame_cfa (void *baton)
1351 struct needs_frame_baton *nf_baton = baton;
1353 nf_baton->needs_frame = 1;
1357 /* Thread-local accesses do require a frame. */
1359 needs_frame_tls_address (void *baton, CORE_ADDR offset)
1361 struct needs_frame_baton *nf_baton = baton;
1363 nf_baton->needs_frame = 1;
1367 /* Helper interface of per_cu_dwarf_call for dwarf2_loc_desc_needs_frame. */
1370 needs_frame_dwarf_call (struct dwarf_expr_context *ctx, size_t die_offset)
1372 struct needs_frame_baton *nf_baton = ctx->baton;
1374 per_cu_dwarf_call (ctx, die_offset, nf_baton->per_cu,
1375 ctx->funcs->get_frame_pc, ctx->baton);
1378 /* Virtual method table for dwarf2_loc_desc_needs_frame below. */
1380 static const struct dwarf_expr_context_funcs needs_frame_ctx_funcs =
1382 needs_frame_read_reg,
1383 needs_frame_read_mem,
1384 needs_frame_frame_base,
1385 needs_frame_frame_cfa,
1386 needs_frame_frame_cfa, /* get_frame_pc */
1387 needs_frame_tls_address,
1388 needs_frame_dwarf_call,
1389 NULL /* get_base_type */
1392 /* Return non-zero iff the location expression at DATA (length SIZE)
1393 requires a frame to evaluate. */
1396 dwarf2_loc_desc_needs_frame (const gdb_byte *data, unsigned short size,
1397 struct dwarf2_per_cu_data *per_cu)
1399 struct needs_frame_baton baton;
1400 struct dwarf_expr_context *ctx;
1402 struct cleanup *old_chain;
1403 struct objfile *objfile = dwarf2_per_cu_objfile (per_cu);
1405 baton.needs_frame = 0;
1406 baton.per_cu = per_cu;
1408 ctx = new_dwarf_expr_context ();
1409 old_chain = make_cleanup_free_dwarf_expr_context (ctx);
1410 make_cleanup_value_free_to_mark (value_mark ());
1412 ctx->gdbarch = get_objfile_arch (objfile);
1413 ctx->addr_size = dwarf2_per_cu_addr_size (per_cu);
1414 ctx->offset = dwarf2_per_cu_text_offset (per_cu);
1415 ctx->baton = &baton;
1416 ctx->funcs = &needs_frame_ctx_funcs;
1418 dwarf_expr_eval (ctx, data, size);
1420 in_reg = ctx->location == DWARF_VALUE_REGISTER;
1422 if (ctx->num_pieces > 0)
1426 /* If the location has several pieces, and any of them are in
1427 registers, then we will need a frame to fetch them from. */
1428 for (i = 0; i < ctx->num_pieces; i++)
1429 if (ctx->pieces[i].location == DWARF_VALUE_REGISTER)
1433 do_cleanups (old_chain);
1435 return baton.needs_frame || in_reg;
1438 /* A helper function that throws an unimplemented error mentioning a
1439 given DWARF operator. */
1442 unimplemented (unsigned int op)
1444 const char *name = dwarf_stack_op_name (op);
1447 error (_("DWARF operator %s cannot be translated to an agent expression"),
1450 error (_("Unknown DWARF operator 0x%02x cannot be translated "
1451 "to an agent expression"),
1455 /* A helper function to convert a DWARF register to an arch register.
1456 ARCH is the architecture.
1457 DWARF_REG is the register.
1458 This will throw an exception if the DWARF register cannot be
1459 translated to an architecture register. */
1462 translate_register (struct gdbarch *arch, int dwarf_reg)
1464 int reg = gdbarch_dwarf2_reg_to_regnum (arch, dwarf_reg);
1466 error (_("Unable to access DWARF register number %d"), dwarf_reg);
1470 /* A helper function that emits an access to memory. ARCH is the
1471 target architecture. EXPR is the expression which we are building.
1472 NBITS is the number of bits we want to read. This emits the
1473 opcodes needed to read the memory and then extract the desired
1477 access_memory (struct gdbarch *arch, struct agent_expr *expr, ULONGEST nbits)
1479 ULONGEST nbytes = (nbits + 7) / 8;
1481 gdb_assert (nbits > 0 && nbits <= sizeof (LONGEST));
1484 ax_trace_quick (expr, nbytes);
1487 ax_simple (expr, aop_ref8);
1488 else if (nbits <= 16)
1489 ax_simple (expr, aop_ref16);
1490 else if (nbits <= 32)
1491 ax_simple (expr, aop_ref32);
1493 ax_simple (expr, aop_ref64);
1495 /* If we read exactly the number of bytes we wanted, we're done. */
1496 if (8 * nbytes == nbits)
1499 if (gdbarch_bits_big_endian (arch))
1501 /* On a bits-big-endian machine, we want the high-order
1503 ax_const_l (expr, 8 * nbytes - nbits);
1504 ax_simple (expr, aop_rsh_unsigned);
1508 /* On a bits-little-endian box, we want the low-order NBITS. */
1509 ax_zero_ext (expr, nbits);
1513 /* A helper function to return the frame's PC. */
1516 get_ax_pc (void *baton)
1518 struct agent_expr *expr = baton;
1523 /* Compile a DWARF location expression to an agent expression.
1525 EXPR is the agent expression we are building.
1526 LOC is the agent value we modify.
1527 ARCH is the architecture.
1528 ADDR_SIZE is the size of addresses, in bytes.
1529 OP_PTR is the start of the location expression.
1530 OP_END is one past the last byte of the location expression.
1532 This will throw an exception for various kinds of errors -- for
1533 example, if the expression cannot be compiled, or if the expression
1537 dwarf2_compile_expr_to_ax (struct agent_expr *expr, struct axs_value *loc,
1538 struct gdbarch *arch, unsigned int addr_size,
1539 const gdb_byte *op_ptr, const gdb_byte *op_end,
1540 struct dwarf2_per_cu_data *per_cu)
1542 struct cleanup *cleanups;
1544 VEC(int) *dw_labels = NULL, *patches = NULL;
1545 const gdb_byte * const base = op_ptr;
1546 const gdb_byte *previous_piece = op_ptr;
1547 enum bfd_endian byte_order = gdbarch_byte_order (arch);
1548 ULONGEST bits_collected = 0;
1549 unsigned int addr_size_bits = 8 * addr_size;
1550 int bits_big_endian = gdbarch_bits_big_endian (arch);
1552 offsets = xmalloc ((op_end - op_ptr) * sizeof (int));
1553 cleanups = make_cleanup (xfree, offsets);
1555 for (i = 0; i < op_end - op_ptr; ++i)
1558 make_cleanup (VEC_cleanup (int), &dw_labels);
1559 make_cleanup (VEC_cleanup (int), &patches);
1561 /* By default we are making an address. */
1562 loc->kind = axs_lvalue_memory;
1564 while (op_ptr < op_end)
1566 enum dwarf_location_atom op = *op_ptr;
1567 ULONGEST uoffset, reg;
1571 offsets[op_ptr - base] = expr->len;
1574 /* Our basic approach to code generation is to map DWARF
1575 operations directly to AX operations. However, there are
1578 First, DWARF works on address-sized units, but AX always uses
1579 LONGEST. For most operations we simply ignore this
1580 difference; instead we generate sign extensions as needed
1581 before division and comparison operations. It would be nice
1582 to omit the sign extensions, but there is no way to determine
1583 the size of the target's LONGEST. (This code uses the size
1584 of the host LONGEST in some cases -- that is a bug but it is
1587 Second, some DWARF operations cannot be translated to AX.
1588 For these we simply fail. See
1589 http://sourceware.org/bugzilla/show_bug.cgi?id=11662. */
1624 ax_const_l (expr, op - DW_OP_lit0);
1628 uoffset = extract_unsigned_integer (op_ptr, addr_size, byte_order);
1629 op_ptr += addr_size;
1630 /* Some versions of GCC emit DW_OP_addr before
1631 DW_OP_GNU_push_tls_address. In this case the value is an
1632 index, not an address. We don't support things like
1633 branching between the address and the TLS op. */
1634 if (op_ptr >= op_end || *op_ptr != DW_OP_GNU_push_tls_address)
1635 uoffset += dwarf2_per_cu_text_offset (per_cu);
1636 ax_const_l (expr, uoffset);
1640 ax_const_l (expr, extract_unsigned_integer (op_ptr, 1, byte_order));
1644 ax_const_l (expr, extract_signed_integer (op_ptr, 1, byte_order));
1648 ax_const_l (expr, extract_unsigned_integer (op_ptr, 2, byte_order));
1652 ax_const_l (expr, extract_signed_integer (op_ptr, 2, byte_order));
1656 ax_const_l (expr, extract_unsigned_integer (op_ptr, 4, byte_order));
1660 ax_const_l (expr, extract_signed_integer (op_ptr, 4, byte_order));
1664 ax_const_l (expr, extract_unsigned_integer (op_ptr, 8, byte_order));
1668 ax_const_l (expr, extract_signed_integer (op_ptr, 8, byte_order));
1672 op_ptr = read_uleb128 (op_ptr, op_end, &uoffset);
1673 ax_const_l (expr, uoffset);
1676 op_ptr = read_sleb128 (op_ptr, op_end, &offset);
1677 ax_const_l (expr, offset);
1712 dwarf_expr_require_composition (op_ptr, op_end, "DW_OP_regx");
1713 loc->u.reg = translate_register (arch, op - DW_OP_reg0);
1714 loc->kind = axs_lvalue_register;
1718 op_ptr = read_uleb128 (op_ptr, op_end, ®);
1719 dwarf_expr_require_composition (op_ptr, op_end, "DW_OP_regx");
1720 loc->u.reg = translate_register (arch, reg);
1721 loc->kind = axs_lvalue_register;
1724 case DW_OP_implicit_value:
1728 op_ptr = read_uleb128 (op_ptr, op_end, &len);
1729 if (op_ptr + len > op_end)
1730 error (_("DW_OP_implicit_value: too few bytes available."));
1731 if (len > sizeof (ULONGEST))
1732 error (_("Cannot translate DW_OP_implicit_value of %d bytes"),
1735 ax_const_l (expr, extract_unsigned_integer (op_ptr, len,
1738 dwarf_expr_require_composition (op_ptr, op_end,
1739 "DW_OP_implicit_value");
1741 loc->kind = axs_rvalue;
1745 case DW_OP_stack_value:
1746 dwarf_expr_require_composition (op_ptr, op_end, "DW_OP_stack_value");
1747 loc->kind = axs_rvalue;
1782 op_ptr = read_sleb128 (op_ptr, op_end, &offset);
1783 i = translate_register (arch, op - DW_OP_breg0);
1787 ax_const_l (expr, offset);
1788 ax_simple (expr, aop_add);
1793 op_ptr = read_uleb128 (op_ptr, op_end, ®);
1794 op_ptr = read_sleb128 (op_ptr, op_end, &offset);
1795 i = translate_register (arch, reg);
1799 ax_const_l (expr, offset);
1800 ax_simple (expr, aop_add);
1806 const gdb_byte *datastart;
1808 unsigned int before_stack_len;
1810 struct symbol *framefunc;
1811 LONGEST base_offset = 0;
1813 b = block_for_pc (expr->scope);
1816 error (_("No block found for address"));
1818 framefunc = block_linkage_function (b);
1821 error (_("No function found for block"));
1823 dwarf_expr_frame_base_1 (framefunc, expr->scope,
1824 &datastart, &datalen);
1826 op_ptr = read_sleb128 (op_ptr, op_end, &offset);
1827 dwarf2_compile_expr_to_ax (expr, loc, arch, addr_size, datastart,
1828 datastart + datalen, per_cu);
1832 ax_const_l (expr, offset);
1833 ax_simple (expr, aop_add);
1836 loc->kind = axs_lvalue_memory;
1841 ax_simple (expr, aop_dup);
1845 ax_simple (expr, aop_pop);
1850 ax_pick (expr, offset);
1854 ax_simple (expr, aop_swap);
1862 ax_simple (expr, aop_rot);
1866 case DW_OP_deref_size:
1870 if (op == DW_OP_deref_size)
1878 ax_simple (expr, aop_ref8);
1881 ax_simple (expr, aop_ref16);
1884 ax_simple (expr, aop_ref32);
1887 ax_simple (expr, aop_ref64);
1890 /* Note that dwarf_stack_op_name will never return
1892 error (_("Unsupported size %d in %s"),
1893 size, dwarf_stack_op_name (op));
1899 /* Sign extend the operand. */
1900 ax_ext (expr, addr_size_bits);
1901 ax_simple (expr, aop_dup);
1902 ax_const_l (expr, 0);
1903 ax_simple (expr, aop_less_signed);
1904 ax_simple (expr, aop_log_not);
1905 i = ax_goto (expr, aop_if_goto);
1906 /* We have to emit 0 - X. */
1907 ax_const_l (expr, 0);
1908 ax_simple (expr, aop_swap);
1909 ax_simple (expr, aop_sub);
1910 ax_label (expr, i, expr->len);
1914 /* No need to sign extend here. */
1915 ax_const_l (expr, 0);
1916 ax_simple (expr, aop_swap);
1917 ax_simple (expr, aop_sub);
1921 /* Sign extend the operand. */
1922 ax_ext (expr, addr_size_bits);
1923 ax_simple (expr, aop_bit_not);
1926 case DW_OP_plus_uconst:
1927 op_ptr = read_uleb128 (op_ptr, op_end, ®);
1928 /* It would be really weird to emit `DW_OP_plus_uconst 0',
1929 but we micro-optimize anyhow. */
1932 ax_const_l (expr, reg);
1933 ax_simple (expr, aop_add);
1938 ax_simple (expr, aop_bit_and);
1942 /* Sign extend the operands. */
1943 ax_ext (expr, addr_size_bits);
1944 ax_simple (expr, aop_swap);
1945 ax_ext (expr, addr_size_bits);
1946 ax_simple (expr, aop_swap);
1947 ax_simple (expr, aop_div_signed);
1951 ax_simple (expr, aop_sub);
1955 ax_simple (expr, aop_rem_unsigned);
1959 ax_simple (expr, aop_mul);
1963 ax_simple (expr, aop_bit_or);
1967 ax_simple (expr, aop_add);
1971 ax_simple (expr, aop_lsh);
1975 ax_simple (expr, aop_rsh_unsigned);
1979 ax_simple (expr, aop_rsh_signed);
1983 ax_simple (expr, aop_bit_xor);
1987 /* Sign extend the operands. */
1988 ax_ext (expr, addr_size_bits);
1989 ax_simple (expr, aop_swap);
1990 ax_ext (expr, addr_size_bits);
1991 /* Note no swap here: A <= B is !(B < A). */
1992 ax_simple (expr, aop_less_signed);
1993 ax_simple (expr, aop_log_not);
1997 /* Sign extend the operands. */
1998 ax_ext (expr, addr_size_bits);
1999 ax_simple (expr, aop_swap);
2000 ax_ext (expr, addr_size_bits);
2001 ax_simple (expr, aop_swap);
2002 /* A >= B is !(A < B). */
2003 ax_simple (expr, aop_less_signed);
2004 ax_simple (expr, aop_log_not);
2008 /* Sign extend the operands. */
2009 ax_ext (expr, addr_size_bits);
2010 ax_simple (expr, aop_swap);
2011 ax_ext (expr, addr_size_bits);
2012 /* No need for a second swap here. */
2013 ax_simple (expr, aop_equal);
2017 /* Sign extend the operands. */
2018 ax_ext (expr, addr_size_bits);
2019 ax_simple (expr, aop_swap);
2020 ax_ext (expr, addr_size_bits);
2021 ax_simple (expr, aop_swap);
2022 ax_simple (expr, aop_less_signed);
2026 /* Sign extend the operands. */
2027 ax_ext (expr, addr_size_bits);
2028 ax_simple (expr, aop_swap);
2029 ax_ext (expr, addr_size_bits);
2030 /* Note no swap here: A > B is B < A. */
2031 ax_simple (expr, aop_less_signed);
2035 /* Sign extend the operands. */
2036 ax_ext (expr, addr_size_bits);
2037 ax_simple (expr, aop_swap);
2038 ax_ext (expr, addr_size_bits);
2039 /* No need for a swap here. */
2040 ax_simple (expr, aop_equal);
2041 ax_simple (expr, aop_log_not);
2044 case DW_OP_call_frame_cfa:
2045 dwarf2_compile_cfa_to_ax (expr, loc, arch, expr->scope, per_cu);
2046 loc->kind = axs_lvalue_memory;
2049 case DW_OP_GNU_push_tls_address:
2054 offset = extract_signed_integer (op_ptr, 2, byte_order);
2056 i = ax_goto (expr, aop_goto);
2057 VEC_safe_push (int, dw_labels, op_ptr + offset - base);
2058 VEC_safe_push (int, patches, i);
2062 offset = extract_signed_integer (op_ptr, 2, byte_order);
2064 /* Zero extend the operand. */
2065 ax_zero_ext (expr, addr_size_bits);
2066 i = ax_goto (expr, aop_if_goto);
2067 VEC_safe_push (int, dw_labels, op_ptr + offset - base);
2068 VEC_safe_push (int, patches, i);
2075 case DW_OP_bit_piece:
2077 ULONGEST size, offset;
2079 if (op_ptr - 1 == previous_piece)
2080 error (_("Cannot translate empty pieces to agent expressions"));
2081 previous_piece = op_ptr - 1;
2083 op_ptr = read_uleb128 (op_ptr, op_end, &size);
2084 if (op == DW_OP_piece)
2090 op_ptr = read_uleb128 (op_ptr, op_end, &offset);
2092 if (bits_collected + size > 8 * sizeof (LONGEST))
2093 error (_("Expression pieces exceed word size"));
2095 /* Access the bits. */
2098 case axs_lvalue_register:
2099 ax_reg (expr, loc->u.reg);
2102 case axs_lvalue_memory:
2103 /* Offset the pointer, if needed. */
2106 ax_const_l (expr, offset / 8);
2107 ax_simple (expr, aop_add);
2110 access_memory (arch, expr, size);
2114 /* For a bits-big-endian target, shift up what we already
2115 have. For a bits-little-endian target, shift up the
2116 new data. Note that there is a potential bug here if
2117 the DWARF expression leaves multiple values on the
2119 if (bits_collected > 0)
2121 if (bits_big_endian)
2123 ax_simple (expr, aop_swap);
2124 ax_const_l (expr, size);
2125 ax_simple (expr, aop_lsh);
2126 /* We don't need a second swap here, because
2127 aop_bit_or is symmetric. */
2131 ax_const_l (expr, size);
2132 ax_simple (expr, aop_lsh);
2134 ax_simple (expr, aop_bit_or);
2137 bits_collected += size;
2138 loc->kind = axs_rvalue;
2142 case DW_OP_GNU_uninit:
2148 struct dwarf2_locexpr_baton block;
2149 int size = (op == DW_OP_call2 ? 2 : 4);
2150 struct cleanup *back_to;
2152 uoffset = extract_unsigned_integer (op_ptr, size, byte_order);
2155 block = dwarf2_fetch_die_location_block (uoffset, per_cu,
2157 back_to = make_cleanup (xfree, (void *) block.data);
2159 /* DW_OP_call_ref is currently not supported. */
2160 gdb_assert (block.per_cu == per_cu);
2162 dwarf2_compile_expr_to_ax (expr, loc, arch, addr_size,
2163 block.data, block.data + block.size,
2166 do_cleanups (back_to);
2170 case DW_OP_call_ref:
2178 /* Patch all the branches we emitted. */
2179 for (i = 0; i < VEC_length (int, patches); ++i)
2181 int targ = offsets[VEC_index (int, dw_labels, i)];
2183 internal_error (__FILE__, __LINE__, _("invalid label"));
2184 ax_label (expr, VEC_index (int, patches, i), targ);
2187 do_cleanups (cleanups);
2191 /* Return the value of SYMBOL in FRAME using the DWARF-2 expression
2192 evaluator to calculate the location. */
2193 static struct value *
2194 locexpr_read_variable (struct symbol *symbol, struct frame_info *frame)
2196 struct dwarf2_locexpr_baton *dlbaton = SYMBOL_LOCATION_BATON (symbol);
2199 val = dwarf2_evaluate_loc_desc (SYMBOL_TYPE (symbol), frame, dlbaton->data,
2200 dlbaton->size, dlbaton->per_cu);
2205 /* Return non-zero iff we need a frame to evaluate SYMBOL. */
2207 locexpr_read_needs_frame (struct symbol *symbol)
2209 struct dwarf2_locexpr_baton *dlbaton = SYMBOL_LOCATION_BATON (symbol);
2211 return dwarf2_loc_desc_needs_frame (dlbaton->data, dlbaton->size,
2215 /* Return true if DATA points to the end of a piece. END is one past
2216 the last byte in the expression. */
2219 piece_end_p (const gdb_byte *data, const gdb_byte *end)
2221 return data == end || data[0] == DW_OP_piece || data[0] == DW_OP_bit_piece;
2224 /* Helper for locexpr_describe_location_piece that finds the name of a
2228 locexpr_regname (struct gdbarch *gdbarch, int dwarf_regnum)
2232 regnum = gdbarch_dwarf2_reg_to_regnum (gdbarch, dwarf_regnum);
2233 return gdbarch_register_name (gdbarch, regnum);
2236 /* Nicely describe a single piece of a location, returning an updated
2237 position in the bytecode sequence. This function cannot recognize
2238 all locations; if a location is not recognized, it simply returns
2241 static const gdb_byte *
2242 locexpr_describe_location_piece (struct symbol *symbol, struct ui_file *stream,
2243 CORE_ADDR addr, struct objfile *objfile,
2244 const gdb_byte *data, const gdb_byte *end,
2245 unsigned int addr_size)
2247 struct gdbarch *gdbarch = get_objfile_arch (objfile);
2249 if (data[0] >= DW_OP_reg0 && data[0] <= DW_OP_reg31)
2251 fprintf_filtered (stream, _("a variable in $%s"),
2252 locexpr_regname (gdbarch, data[0] - DW_OP_reg0));
2255 else if (data[0] == DW_OP_regx)
2259 data = read_uleb128 (data + 1, end, ®);
2260 fprintf_filtered (stream, _("a variable in $%s"),
2261 locexpr_regname (gdbarch, reg));
2263 else if (data[0] == DW_OP_fbreg)
2266 struct symbol *framefunc;
2268 LONGEST frame_offset;
2269 const gdb_byte *base_data, *new_data, *save_data = data;
2271 LONGEST base_offset = 0;
2273 new_data = read_sleb128 (data + 1, end, &frame_offset);
2274 if (!piece_end_p (new_data, end))
2278 b = block_for_pc (addr);
2281 error (_("No block found for address for symbol \"%s\"."),
2282 SYMBOL_PRINT_NAME (symbol));
2284 framefunc = block_linkage_function (b);
2287 error (_("No function found for block for symbol \"%s\"."),
2288 SYMBOL_PRINT_NAME (symbol));
2290 dwarf_expr_frame_base_1 (framefunc, addr, &base_data, &base_size);
2292 if (base_data[0] >= DW_OP_breg0 && base_data[0] <= DW_OP_breg31)
2294 const gdb_byte *buf_end;
2296 frame_reg = base_data[0] - DW_OP_breg0;
2297 buf_end = read_sleb128 (base_data + 1,
2298 base_data + base_size, &base_offset);
2299 if (buf_end != base_data + base_size)
2300 error (_("Unexpected opcode after "
2301 "DW_OP_breg%u for symbol \"%s\"."),
2302 frame_reg, SYMBOL_PRINT_NAME (symbol));
2304 else if (base_data[0] >= DW_OP_reg0 && base_data[0] <= DW_OP_reg31)
2306 /* The frame base is just the register, with no offset. */
2307 frame_reg = base_data[0] - DW_OP_reg0;
2312 /* We don't know what to do with the frame base expression,
2313 so we can't trace this variable; give up. */
2317 fprintf_filtered (stream,
2318 _("a variable at frame base reg $%s offset %s+%s"),
2319 locexpr_regname (gdbarch, frame_reg),
2320 plongest (base_offset), plongest (frame_offset));
2322 else if (data[0] >= DW_OP_breg0 && data[0] <= DW_OP_breg31
2323 && piece_end_p (data, end))
2327 data = read_sleb128 (data + 1, end, &offset);
2329 fprintf_filtered (stream,
2330 _("a variable at offset %s from base reg $%s"),
2332 locexpr_regname (gdbarch, data[0] - DW_OP_breg0));
2335 /* The location expression for a TLS variable looks like this (on a
2338 DW_AT_location : 10 byte block: 3 4 0 0 0 0 0 0 0 e0
2339 (DW_OP_addr: 4; DW_OP_GNU_push_tls_address)
2341 0x3 is the encoding for DW_OP_addr, which has an operand as long
2342 as the size of an address on the target machine (here is 8
2343 bytes). Note that more recent version of GCC emit DW_OP_const4u
2344 or DW_OP_const8u, depending on address size, rather than
2345 DW_OP_addr. 0xe0 is the encoding for DW_OP_GNU_push_tls_address.
2346 The operand represents the offset at which the variable is within
2347 the thread local storage. */
2349 else if (data + 1 + addr_size < end
2350 && (data[0] == DW_OP_addr
2351 || (addr_size == 4 && data[0] == DW_OP_const4u)
2352 || (addr_size == 8 && data[0] == DW_OP_const8u))
2353 && data[1 + addr_size] == DW_OP_GNU_push_tls_address
2354 && piece_end_p (data + 2 + addr_size, end))
2357 offset = extract_unsigned_integer (data + 1, addr_size,
2358 gdbarch_byte_order (gdbarch));
2360 fprintf_filtered (stream,
2361 _("a thread-local variable at offset 0x%s "
2362 "in the thread-local storage for `%s'"),
2363 phex_nz (offset, addr_size), objfile->name);
2365 data += 1 + addr_size + 1;
2367 else if (data[0] >= DW_OP_lit0
2368 && data[0] <= DW_OP_lit31
2370 && data[1] == DW_OP_stack_value)
2372 fprintf_filtered (stream, _("the constant %d"), data[0] - DW_OP_lit0);
2379 /* Disassemble an expression, stopping at the end of a piece or at the
2380 end of the expression. Returns a pointer to the next unread byte
2381 in the input expression. If ALL is nonzero, then this function
2382 will keep going until it reaches the end of the expression. */
2384 static const gdb_byte *
2385 disassemble_dwarf_expression (struct ui_file *stream,
2386 struct gdbarch *arch, unsigned int addr_size,
2388 const gdb_byte *data, const gdb_byte *end,
2390 struct dwarf2_per_cu_data *per_cu)
2392 const gdb_byte *start = data;
2394 fprintf_filtered (stream, _("a complex DWARF expression:\n"));
2398 || (data[0] != DW_OP_piece && data[0] != DW_OP_bit_piece)))
2400 enum dwarf_location_atom op = *data++;
2405 name = dwarf_stack_op_name (op);
2408 error (_("Unrecognized DWARF opcode 0x%02x at %ld"),
2409 op, (long) (data - 1 - start));
2410 fprintf_filtered (stream, " % 4ld: %s", (long) (data - 1 - start), name);
2415 ul = extract_unsigned_integer (data, addr_size,
2416 gdbarch_byte_order (arch));
2418 fprintf_filtered (stream, " 0x%s", phex_nz (ul, addr_size));
2422 ul = extract_unsigned_integer (data, 1, gdbarch_byte_order (arch));
2424 fprintf_filtered (stream, " %s", pulongest (ul));
2427 l = extract_signed_integer (data, 1, gdbarch_byte_order (arch));
2429 fprintf_filtered (stream, " %s", plongest (l));
2432 ul = extract_unsigned_integer (data, 2, gdbarch_byte_order (arch));
2434 fprintf_filtered (stream, " %s", pulongest (ul));
2437 l = extract_signed_integer (data, 2, gdbarch_byte_order (arch));
2439 fprintf_filtered (stream, " %s", plongest (l));
2442 ul = extract_unsigned_integer (data, 4, gdbarch_byte_order (arch));
2444 fprintf_filtered (stream, " %s", pulongest (ul));
2447 l = extract_signed_integer (data, 4, gdbarch_byte_order (arch));
2449 fprintf_filtered (stream, " %s", plongest (l));
2452 ul = extract_unsigned_integer (data, 8, gdbarch_byte_order (arch));
2454 fprintf_filtered (stream, " %s", pulongest (ul));
2457 l = extract_signed_integer (data, 8, gdbarch_byte_order (arch));
2459 fprintf_filtered (stream, " %s", plongest (l));
2462 data = read_uleb128 (data, end, &ul);
2463 fprintf_filtered (stream, " %s", pulongest (ul));
2466 data = read_sleb128 (data, end, &l);
2467 fprintf_filtered (stream, " %s", plongest (l));
2502 fprintf_filtered (stream, " [$%s]",
2503 locexpr_regname (arch, op - DW_OP_reg0));
2507 data = read_uleb128 (data, end, &ul);
2508 fprintf_filtered (stream, " %s [$%s]", pulongest (ul),
2509 locexpr_regname (arch, (int) ul));
2512 case DW_OP_implicit_value:
2513 data = read_uleb128 (data, end, &ul);
2515 fprintf_filtered (stream, " %s", pulongest (ul));
2550 data = read_sleb128 (data, end, &l);
2551 fprintf_filtered (stream, " %s [$%s]", plongest (l),
2552 locexpr_regname (arch, op - DW_OP_breg0));
2556 data = read_uleb128 (data, end, &ul);
2557 data = read_sleb128 (data, end, &l);
2558 fprintf_filtered (stream, " register %s [$%s] offset %s",
2560 locexpr_regname (arch, (int) ul),
2565 data = read_sleb128 (data, end, &l);
2566 fprintf_filtered (stream, " %s", plongest (l));
2569 case DW_OP_xderef_size:
2570 case DW_OP_deref_size:
2572 fprintf_filtered (stream, " %d", *data);
2576 case DW_OP_plus_uconst:
2577 data = read_uleb128 (data, end, &ul);
2578 fprintf_filtered (stream, " %s", pulongest (ul));
2582 l = extract_signed_integer (data, 2, gdbarch_byte_order (arch));
2584 fprintf_filtered (stream, " to %ld",
2585 (long) (data + l - start));
2589 l = extract_signed_integer (data, 2, gdbarch_byte_order (arch));
2591 fprintf_filtered (stream, " %ld",
2592 (long) (data + l - start));
2596 ul = extract_unsigned_integer (data, 2, gdbarch_byte_order (arch));
2598 fprintf_filtered (stream, " offset %s", phex_nz (ul, 2));
2602 ul = extract_unsigned_integer (data, 4, gdbarch_byte_order (arch));
2604 fprintf_filtered (stream, " offset %s", phex_nz (ul, 4));
2607 case DW_OP_call_ref:
2608 ul = extract_unsigned_integer (data, offset_size,
2609 gdbarch_byte_order (arch));
2610 data += offset_size;
2611 fprintf_filtered (stream, " offset %s", phex_nz (ul, offset_size));
2615 data = read_uleb128 (data, end, &ul);
2616 fprintf_filtered (stream, " %s (bytes)", pulongest (ul));
2619 case DW_OP_bit_piece:
2623 data = read_uleb128 (data, end, &ul);
2624 data = read_uleb128 (data, end, &offset);
2625 fprintf_filtered (stream, " size %s offset %s (bits)",
2626 pulongest (ul), pulongest (offset));
2630 case DW_OP_GNU_implicit_pointer:
2632 ul = extract_unsigned_integer (data, offset_size,
2633 gdbarch_byte_order (arch));
2634 data += offset_size;
2636 data = read_sleb128 (data, end, &l);
2638 fprintf_filtered (stream, " DIE %s offset %s",
2639 phex_nz (ul, offset_size),
2644 case DW_OP_GNU_deref_type:
2646 int addr_size = *data++;
2650 data = read_uleb128 (data, end, &offset);
2651 type = dwarf2_get_die_type (offset, per_cu);
2652 fprintf_filtered (stream, "<");
2653 type_print (type, "", stream, -1);
2654 fprintf_filtered (stream, " [0x%s]> %d", phex_nz (offset, 0),
2659 case DW_OP_GNU_const_type:
2664 data = read_uleb128 (data, end, &type_die);
2665 type = dwarf2_get_die_type (type_die, per_cu);
2666 fprintf_filtered (stream, "<");
2667 type_print (type, "", stream, -1);
2668 fprintf_filtered (stream, " [0x%s]>", phex_nz (type_die, 0));
2672 case DW_OP_GNU_regval_type:
2674 ULONGEST type_die, reg;
2677 data = read_uleb128 (data, end, ®);
2678 data = read_uleb128 (data, end, &type_die);
2680 type = dwarf2_get_die_type (type_die, per_cu);
2681 fprintf_filtered (stream, "<");
2682 type_print (type, "", stream, -1);
2683 fprintf_filtered (stream, " [0x%s]> [$%s]", phex_nz (type_die, 0),
2684 locexpr_regname (arch, reg));
2688 case DW_OP_GNU_convert:
2689 case DW_OP_GNU_reinterpret:
2693 data = read_uleb128 (data, end, &type_die);
2696 fprintf_filtered (stream, "<0>");
2701 type = dwarf2_get_die_type (type_die, per_cu);
2702 fprintf_filtered (stream, "<");
2703 type_print (type, "", stream, -1);
2704 fprintf_filtered (stream, " [0x%s]>", phex_nz (type_die, 0));
2710 fprintf_filtered (stream, "\n");
2716 /* Describe a single location, which may in turn consist of multiple
2720 locexpr_describe_location_1 (struct symbol *symbol, CORE_ADDR addr,
2721 struct ui_file *stream,
2722 const gdb_byte *data, int size,
2723 struct objfile *objfile, unsigned int addr_size,
2724 int offset_size, struct dwarf2_per_cu_data *per_cu)
2726 const gdb_byte *end = data + size;
2727 int first_piece = 1, bad = 0;
2731 const gdb_byte *here = data;
2732 int disassemble = 1;
2737 fprintf_filtered (stream, _(", and "));
2739 if (!dwarf2_always_disassemble)
2741 data = locexpr_describe_location_piece (symbol, stream,
2743 data, end, addr_size);
2744 /* If we printed anything, or if we have an empty piece,
2745 then don't disassemble. */
2747 || data[0] == DW_OP_piece
2748 || data[0] == DW_OP_bit_piece)
2752 data = disassemble_dwarf_expression (stream,
2753 get_objfile_arch (objfile),
2754 addr_size, offset_size, data, end,
2755 dwarf2_always_disassemble,
2760 int empty = data == here;
2763 fprintf_filtered (stream, " ");
2764 if (data[0] == DW_OP_piece)
2768 data = read_uleb128 (data + 1, end, &bytes);
2771 fprintf_filtered (stream, _("an empty %s-byte piece"),
2774 fprintf_filtered (stream, _(" [%s-byte piece]"),
2777 else if (data[0] == DW_OP_bit_piece)
2779 ULONGEST bits, offset;
2781 data = read_uleb128 (data + 1, end, &bits);
2782 data = read_uleb128 (data, end, &offset);
2785 fprintf_filtered (stream,
2786 _("an empty %s-bit piece"),
2789 fprintf_filtered (stream,
2790 _(" [%s-bit piece, offset %s bits]"),
2791 pulongest (bits), pulongest (offset));
2801 if (bad || data > end)
2802 error (_("Corrupted DWARF2 expression for \"%s\"."),
2803 SYMBOL_PRINT_NAME (symbol));
2806 /* Print a natural-language description of SYMBOL to STREAM. This
2807 version is for a symbol with a single location. */
2810 locexpr_describe_location (struct symbol *symbol, CORE_ADDR addr,
2811 struct ui_file *stream)
2813 struct dwarf2_locexpr_baton *dlbaton = SYMBOL_LOCATION_BATON (symbol);
2814 struct objfile *objfile = dwarf2_per_cu_objfile (dlbaton->per_cu);
2815 unsigned int addr_size = dwarf2_per_cu_addr_size (dlbaton->per_cu);
2816 int offset_size = dwarf2_per_cu_offset_size (dlbaton->per_cu);
2818 locexpr_describe_location_1 (symbol, addr, stream,
2819 dlbaton->data, dlbaton->size,
2820 objfile, addr_size, offset_size,
2824 /* Describe the location of SYMBOL as an agent value in VALUE, generating
2825 any necessary bytecode in AX. */
2828 locexpr_tracepoint_var_ref (struct symbol *symbol, struct gdbarch *gdbarch,
2829 struct agent_expr *ax, struct axs_value *value)
2831 struct dwarf2_locexpr_baton *dlbaton = SYMBOL_LOCATION_BATON (symbol);
2832 unsigned int addr_size = dwarf2_per_cu_addr_size (dlbaton->per_cu);
2834 if (dlbaton->data == NULL || dlbaton->size == 0)
2835 value->optimized_out = 1;
2837 dwarf2_compile_expr_to_ax (ax, value, gdbarch, addr_size,
2838 dlbaton->data, dlbaton->data + dlbaton->size,
2842 /* The set of location functions used with the DWARF-2 expression
2844 const struct symbol_computed_ops dwarf2_locexpr_funcs = {
2845 locexpr_read_variable,
2846 locexpr_read_needs_frame,
2847 locexpr_describe_location,
2848 locexpr_tracepoint_var_ref
2852 /* Wrapper functions for location lists. These generally find
2853 the appropriate location expression and call something above. */
2855 /* Return the value of SYMBOL in FRAME using the DWARF-2 expression
2856 evaluator to calculate the location. */
2857 static struct value *
2858 loclist_read_variable (struct symbol *symbol, struct frame_info *frame)
2860 struct dwarf2_loclist_baton *dlbaton = SYMBOL_LOCATION_BATON (symbol);
2862 const gdb_byte *data;
2864 CORE_ADDR pc = frame ? get_frame_address_in_block (frame) : 0;
2866 data = dwarf2_find_location_expression (dlbaton, &size, pc);
2868 val = allocate_optimized_out_value (SYMBOL_TYPE (symbol));
2870 val = dwarf2_evaluate_loc_desc (SYMBOL_TYPE (symbol), frame, data, size,
2876 /* Return non-zero iff we need a frame to evaluate SYMBOL. */
2878 loclist_read_needs_frame (struct symbol *symbol)
2880 /* If there's a location list, then assume we need to have a frame
2881 to choose the appropriate location expression. With tracking of
2882 global variables this is not necessarily true, but such tracking
2883 is disabled in GCC at the moment until we figure out how to
2889 /* Print a natural-language description of SYMBOL to STREAM. This
2890 version applies when there is a list of different locations, each
2891 with a specified address range. */
2894 loclist_describe_location (struct symbol *symbol, CORE_ADDR addr,
2895 struct ui_file *stream)
2897 struct dwarf2_loclist_baton *dlbaton = SYMBOL_LOCATION_BATON (symbol);
2898 CORE_ADDR low, high;
2899 const gdb_byte *loc_ptr, *buf_end;
2900 int length, first = 1;
2901 struct objfile *objfile = dwarf2_per_cu_objfile (dlbaton->per_cu);
2902 struct gdbarch *gdbarch = get_objfile_arch (objfile);
2903 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
2904 unsigned int addr_size = dwarf2_per_cu_addr_size (dlbaton->per_cu);
2905 int offset_size = dwarf2_per_cu_offset_size (dlbaton->per_cu);
2906 int signed_addr_p = bfd_get_sign_extend_vma (objfile->obfd);
2907 CORE_ADDR base_mask = ~(~(CORE_ADDR)1 << (addr_size * 8 - 1));
2908 /* Adjust base_address for relocatable objects. */
2909 CORE_ADDR base_offset = dwarf2_per_cu_text_offset (dlbaton->per_cu);
2910 CORE_ADDR base_address = dlbaton->base_address + base_offset;
2912 loc_ptr = dlbaton->data;
2913 buf_end = dlbaton->data + dlbaton->size;
2915 fprintf_filtered (stream, _("multi-location:\n"));
2917 /* Iterate through locations until we run out. */
2920 if (buf_end - loc_ptr < 2 * addr_size)
2921 error (_("Corrupted DWARF expression for symbol \"%s\"."),
2922 SYMBOL_PRINT_NAME (symbol));
2925 low = extract_signed_integer (loc_ptr, addr_size, byte_order);
2927 low = extract_unsigned_integer (loc_ptr, addr_size, byte_order);
2928 loc_ptr += addr_size;
2931 high = extract_signed_integer (loc_ptr, addr_size, byte_order);
2933 high = extract_unsigned_integer (loc_ptr, addr_size, byte_order);
2934 loc_ptr += addr_size;
2936 /* A base-address-selection entry. */
2937 if ((low & base_mask) == base_mask)
2939 base_address = high + base_offset;
2940 fprintf_filtered (stream, _(" Base address %s"),
2941 paddress (gdbarch, base_address));
2945 /* An end-of-list entry. */
2946 if (low == 0 && high == 0)
2949 /* Otherwise, a location expression entry. */
2950 low += base_address;
2951 high += base_address;
2953 length = extract_unsigned_integer (loc_ptr, 2, byte_order);
2956 /* (It would improve readability to print only the minimum
2957 necessary digits of the second number of the range.) */
2958 fprintf_filtered (stream, _(" Range %s-%s: "),
2959 paddress (gdbarch, low), paddress (gdbarch, high));
2961 /* Now describe this particular location. */
2962 locexpr_describe_location_1 (symbol, low, stream, loc_ptr, length,
2963 objfile, addr_size, offset_size,
2966 fprintf_filtered (stream, "\n");
2972 /* Describe the location of SYMBOL as an agent value in VALUE, generating
2973 any necessary bytecode in AX. */
2975 loclist_tracepoint_var_ref (struct symbol *symbol, struct gdbarch *gdbarch,
2976 struct agent_expr *ax, struct axs_value *value)
2978 struct dwarf2_loclist_baton *dlbaton = SYMBOL_LOCATION_BATON (symbol);
2979 const gdb_byte *data;
2981 unsigned int addr_size = dwarf2_per_cu_addr_size (dlbaton->per_cu);
2983 data = dwarf2_find_location_expression (dlbaton, &size, ax->scope);
2984 if (data == NULL || size == 0)
2985 value->optimized_out = 1;
2987 dwarf2_compile_expr_to_ax (ax, value, gdbarch, addr_size, data, data + size,
2991 /* The set of location functions used with the DWARF-2 expression
2992 evaluator and location lists. */
2993 const struct symbol_computed_ops dwarf2_loclist_funcs = {
2994 loclist_read_variable,
2995 loclist_read_needs_frame,
2996 loclist_describe_location,
2997 loclist_tracepoint_var_ref