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;
48 dwarf_expr_frame_base_1 (struct symbol *framefunc, CORE_ADDR pc,
49 const gdb_byte **start, size_t *length);
52 dwarf2_evaluate_loc_desc_full (struct type *type, struct frame_info *frame,
53 const gdb_byte *data, unsigned short size,
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;
269 block = dwarf2_fetch_die_location_block (die_offset, per_cu,
270 get_frame_pc, baton);
272 /* DW_OP_call_ref is currently not supported. */
273 gdb_assert (block.per_cu == per_cu);
275 dwarf_expr_eval (ctx, block.data, block.size);
278 /* Helper interface of per_cu_dwarf_call for dwarf2_evaluate_loc_desc. */
281 dwarf_expr_dwarf_call (struct dwarf_expr_context *ctx, size_t die_offset)
283 struct dwarf_expr_baton *debaton = ctx->baton;
285 return per_cu_dwarf_call (ctx, die_offset, debaton->per_cu,
286 ctx->get_frame_pc, ctx->baton);
291 /* Reference count. */
294 /* The CU from which this closure's expression came. */
295 struct dwarf2_per_cu_data *per_cu;
297 /* The number of pieces used to describe this variable. */
300 /* The target address size, used only for DWARF_VALUE_STACK. */
303 /* The pieces themselves. */
304 struct dwarf_expr_piece *pieces;
307 /* Allocate a closure for a value formed from separately-described
310 static struct piece_closure *
311 allocate_piece_closure (struct dwarf2_per_cu_data *per_cu,
312 int n_pieces, struct dwarf_expr_piece *pieces,
315 struct piece_closure *c = XZALLOC (struct piece_closure);
319 c->n_pieces = n_pieces;
320 c->addr_size = addr_size;
321 c->pieces = XCALLOC (n_pieces, struct dwarf_expr_piece);
323 memcpy (c->pieces, pieces, n_pieces * sizeof (struct dwarf_expr_piece));
328 /* The lowest-level function to extract bits from a byte buffer.
329 SOURCE is the buffer. It is updated if we read to the end of a
331 SOURCE_OFFSET_BITS is the offset of the first bit to read. It is
332 updated to reflect the number of bits actually read.
333 NBITS is the number of bits we want to read. It is updated to
334 reflect the number of bits actually read. This function may read
336 BITS_BIG_ENDIAN is taken directly from gdbarch.
337 This function returns the extracted bits. */
340 extract_bits_primitive (const gdb_byte **source,
341 unsigned int *source_offset_bits,
342 int *nbits, int bits_big_endian)
344 unsigned int avail, mask, datum;
346 gdb_assert (*source_offset_bits < 8);
348 avail = 8 - *source_offset_bits;
352 mask = (1 << avail) - 1;
355 datum >>= 8 - (*source_offset_bits + *nbits);
357 datum >>= *source_offset_bits;
361 *source_offset_bits += avail;
362 if (*source_offset_bits >= 8)
364 *source_offset_bits -= 8;
371 /* Extract some bits from a source buffer and move forward in the
374 SOURCE is the source buffer. It is updated as bytes are read.
375 SOURCE_OFFSET_BITS is the offset into SOURCE. It is updated as
377 NBITS is the number of bits to read.
378 BITS_BIG_ENDIAN is taken directly from gdbarch.
380 This function returns the bits that were read. */
383 extract_bits (const gdb_byte **source, unsigned int *source_offset_bits,
384 int nbits, int bits_big_endian)
388 gdb_assert (nbits > 0 && nbits <= 8);
390 datum = extract_bits_primitive (source, source_offset_bits, &nbits,
396 more = extract_bits_primitive (source, source_offset_bits, &nbits,
408 /* Write some bits into a buffer and move forward in the buffer.
410 DATUM is the bits to write. The low-order bits of DATUM are used.
411 DEST is the destination buffer. It is updated as bytes are
413 DEST_OFFSET_BITS is the bit offset in DEST at which writing is
415 NBITS is the number of valid bits in DATUM.
416 BITS_BIG_ENDIAN is taken directly from gdbarch. */
419 insert_bits (unsigned int datum,
420 gdb_byte *dest, unsigned int dest_offset_bits,
421 int nbits, int bits_big_endian)
425 gdb_assert (dest_offset_bits >= 0 && dest_offset_bits + nbits <= 8);
427 mask = (1 << nbits) - 1;
430 datum <<= 8 - (dest_offset_bits + nbits);
431 mask <<= 8 - (dest_offset_bits + nbits);
435 datum <<= dest_offset_bits;
436 mask <<= dest_offset_bits;
439 gdb_assert ((datum & ~mask) == 0);
441 *dest = (*dest & ~mask) | datum;
444 /* Copy bits from a source to a destination.
446 DEST is where the bits should be written.
447 DEST_OFFSET_BITS is the bit offset into DEST.
448 SOURCE is the source of bits.
449 SOURCE_OFFSET_BITS is the bit offset into SOURCE.
450 BIT_COUNT is the number of bits to copy.
451 BITS_BIG_ENDIAN is taken directly from gdbarch. */
454 copy_bitwise (gdb_byte *dest, unsigned int dest_offset_bits,
455 const gdb_byte *source, unsigned int source_offset_bits,
456 unsigned int bit_count,
459 unsigned int dest_avail;
462 /* Reduce everything to byte-size pieces. */
463 dest += dest_offset_bits / 8;
464 dest_offset_bits %= 8;
465 source += source_offset_bits / 8;
466 source_offset_bits %= 8;
468 dest_avail = 8 - dest_offset_bits % 8;
470 /* See if we can fill the first destination byte. */
471 if (dest_avail < bit_count)
473 datum = extract_bits (&source, &source_offset_bits, dest_avail,
475 insert_bits (datum, dest, dest_offset_bits, dest_avail, bits_big_endian);
477 dest_offset_bits = 0;
478 bit_count -= dest_avail;
481 /* Now, either DEST_OFFSET_BITS is byte-aligned, or we have fewer
482 than 8 bits remaining. */
483 gdb_assert (dest_offset_bits % 8 == 0 || bit_count < 8);
484 for (; bit_count >= 8; bit_count -= 8)
486 datum = extract_bits (&source, &source_offset_bits, 8, bits_big_endian);
487 *dest++ = (gdb_byte) datum;
490 /* Finally, we may have a few leftover bits. */
491 gdb_assert (bit_count <= 8 - dest_offset_bits % 8);
494 datum = extract_bits (&source, &source_offset_bits, bit_count,
496 insert_bits (datum, dest, dest_offset_bits, bit_count, bits_big_endian);
501 read_pieced_value (struct value *v)
505 ULONGEST bits_to_skip;
507 struct piece_closure *c
508 = (struct piece_closure *) value_computed_closure (v);
509 struct frame_info *frame = frame_find_by_id (VALUE_FRAME_ID (v));
511 size_t buffer_size = 0;
513 struct cleanup *cleanup;
515 = gdbarch_bits_big_endian (get_type_arch (value_type (v)));
517 if (value_type (v) != value_enclosing_type (v))
518 internal_error (__FILE__, __LINE__,
519 _("Should not be able to create a lazy value with "
520 "an enclosing type"));
522 cleanup = make_cleanup (free_current_contents, &buffer);
524 contents = value_contents_raw (v);
525 bits_to_skip = 8 * value_offset (v);
526 if (value_bitsize (v))
528 bits_to_skip += value_bitpos (v);
529 type_len = value_bitsize (v);
532 type_len = 8 * TYPE_LENGTH (value_type (v));
534 for (i = 0; i < c->n_pieces && offset < type_len; i++)
536 struct dwarf_expr_piece *p = &c->pieces[i];
537 size_t this_size, this_size_bits;
538 long dest_offset_bits, source_offset_bits, source_offset;
539 const gdb_byte *intermediate_buffer;
541 /* Compute size, source, and destination offsets for copying, in
543 this_size_bits = p->size;
544 if (bits_to_skip > 0 && bits_to_skip >= this_size_bits)
546 bits_to_skip -= this_size_bits;
549 if (this_size_bits > type_len - offset)
550 this_size_bits = type_len - offset;
551 if (bits_to_skip > 0)
553 dest_offset_bits = 0;
554 source_offset_bits = bits_to_skip;
555 this_size_bits -= bits_to_skip;
560 dest_offset_bits = offset;
561 source_offset_bits = 0;
564 this_size = (this_size_bits + source_offset_bits % 8 + 7) / 8;
565 source_offset = source_offset_bits / 8;
566 if (buffer_size < this_size)
568 buffer_size = this_size;
569 buffer = xrealloc (buffer, buffer_size);
571 intermediate_buffer = buffer;
573 /* Copy from the source to DEST_BUFFER. */
576 case DWARF_VALUE_REGISTER:
578 struct gdbarch *arch = get_frame_arch (frame);
579 int gdb_regnum = gdbarch_dwarf2_reg_to_regnum (arch, p->v.value);
580 int reg_offset = source_offset;
582 if (gdbarch_byte_order (arch) == BFD_ENDIAN_BIG
583 && this_size < register_size (arch, gdb_regnum))
585 /* Big-endian, and we want less than full size. */
586 reg_offset = register_size (arch, gdb_regnum) - this_size;
587 /* We want the lower-order THIS_SIZE_BITS of the bytes
588 we extract from the register. */
589 source_offset_bits += 8 * this_size - this_size_bits;
592 if (gdb_regnum != -1)
594 get_frame_register_bytes (frame, gdb_regnum, reg_offset,
599 error (_("Unable to access DWARF register number %s"),
600 paddress (arch, p->v.value));
605 case DWARF_VALUE_MEMORY:
606 if (p->v.mem.in_stack_memory)
607 read_stack (p->v.mem.addr + source_offset, buffer, this_size);
609 read_memory (p->v.mem.addr + source_offset, buffer, this_size);
612 case DWARF_VALUE_STACK:
614 struct gdbarch *gdbarch = get_type_arch (value_type (v));
615 size_t n = this_size;
617 if (n > c->addr_size - source_offset)
618 n = (c->addr_size >= source_offset
619 ? c->addr_size - source_offset
625 else if (source_offset == 0)
626 store_unsigned_integer (buffer, n,
627 gdbarch_byte_order (gdbarch),
631 gdb_byte bytes[sizeof (ULONGEST)];
633 store_unsigned_integer (bytes, n + source_offset,
634 gdbarch_byte_order (gdbarch),
636 memcpy (buffer, bytes + source_offset, n);
641 case DWARF_VALUE_LITERAL:
643 size_t n = this_size;
645 if (n > p->v.literal.length - source_offset)
646 n = (p->v.literal.length >= source_offset
647 ? p->v.literal.length - source_offset
650 intermediate_buffer = p->v.literal.data + source_offset;
654 /* These bits show up as zeros -- but do not cause the value
655 to be considered optimized-out. */
656 case DWARF_VALUE_IMPLICIT_POINTER:
659 case DWARF_VALUE_OPTIMIZED_OUT:
660 set_value_optimized_out (v, 1);
664 internal_error (__FILE__, __LINE__, _("invalid location type"));
667 if (p->location != DWARF_VALUE_OPTIMIZED_OUT
668 && p->location != DWARF_VALUE_IMPLICIT_POINTER)
669 copy_bitwise (contents, dest_offset_bits,
670 intermediate_buffer, source_offset_bits % 8,
671 this_size_bits, bits_big_endian);
673 offset += this_size_bits;
676 do_cleanups (cleanup);
680 write_pieced_value (struct value *to, struct value *from)
684 ULONGEST bits_to_skip;
685 const gdb_byte *contents;
686 struct piece_closure *c
687 = (struct piece_closure *) value_computed_closure (to);
688 struct frame_info *frame = frame_find_by_id (VALUE_FRAME_ID (to));
690 size_t buffer_size = 0;
692 struct cleanup *cleanup;
694 = gdbarch_bits_big_endian (get_type_arch (value_type (to)));
698 set_value_optimized_out (to, 1);
702 cleanup = make_cleanup (free_current_contents, &buffer);
704 contents = value_contents (from);
705 bits_to_skip = 8 * value_offset (to);
706 if (value_bitsize (to))
708 bits_to_skip += value_bitpos (to);
709 type_len = value_bitsize (to);
712 type_len = 8 * TYPE_LENGTH (value_type (to));
714 for (i = 0; i < c->n_pieces && offset < type_len; i++)
716 struct dwarf_expr_piece *p = &c->pieces[i];
717 size_t this_size_bits, this_size;
718 long dest_offset_bits, source_offset_bits, dest_offset, source_offset;
720 const gdb_byte *source_buffer;
722 this_size_bits = p->size;
723 if (bits_to_skip > 0 && bits_to_skip >= this_size_bits)
725 bits_to_skip -= this_size_bits;
728 if (this_size_bits > type_len - offset)
729 this_size_bits = type_len - offset;
730 if (bits_to_skip > 0)
732 dest_offset_bits = bits_to_skip;
733 source_offset_bits = 0;
734 this_size_bits -= bits_to_skip;
739 dest_offset_bits = 0;
740 source_offset_bits = offset;
743 this_size = (this_size_bits + source_offset_bits % 8 + 7) / 8;
744 source_offset = source_offset_bits / 8;
745 dest_offset = dest_offset_bits / 8;
746 if (dest_offset_bits % 8 == 0 && source_offset_bits % 8 == 0)
748 source_buffer = contents + source_offset;
753 if (buffer_size < this_size)
755 buffer_size = this_size;
756 buffer = xrealloc (buffer, buffer_size);
758 source_buffer = buffer;
764 case DWARF_VALUE_REGISTER:
766 struct gdbarch *arch = get_frame_arch (frame);
767 int gdb_regnum = gdbarch_dwarf2_reg_to_regnum (arch, p->v.value);
768 int reg_offset = dest_offset;
770 if (gdbarch_byte_order (arch) == BFD_ENDIAN_BIG
771 && this_size <= register_size (arch, gdb_regnum))
772 /* Big-endian, and we want less than full size. */
773 reg_offset = register_size (arch, gdb_regnum) - this_size;
775 if (gdb_regnum != -1)
779 get_frame_register_bytes (frame, gdb_regnum, reg_offset,
781 copy_bitwise (buffer, dest_offset_bits,
782 contents, source_offset_bits,
787 put_frame_register_bytes (frame, gdb_regnum, reg_offset,
788 this_size, source_buffer);
792 error (_("Unable to write to DWARF register number %s"),
793 paddress (arch, p->v.value));
797 case DWARF_VALUE_MEMORY:
800 /* Only the first and last bytes can possibly have any
802 read_memory (p->v.mem.addr + dest_offset, buffer, 1);
803 read_memory (p->v.mem.addr + dest_offset + this_size - 1,
804 buffer + this_size - 1, 1);
805 copy_bitwise (buffer, dest_offset_bits,
806 contents, source_offset_bits,
811 write_memory (p->v.mem.addr + dest_offset,
812 source_buffer, this_size);
815 set_value_optimized_out (to, 1);
818 offset += this_size_bits;
821 do_cleanups (cleanup);
824 /* A helper function that checks bit validity in a pieced value.
825 CHECK_FOR indicates the kind of validity checking.
826 DWARF_VALUE_MEMORY means to check whether any bit is valid.
827 DWARF_VALUE_OPTIMIZED_OUT means to check whether any bit is
829 DWARF_VALUE_IMPLICIT_POINTER means to check whether the bits are an
833 check_pieced_value_bits (const struct value *value, int bit_offset,
835 enum dwarf_value_location check_for)
837 struct piece_closure *c
838 = (struct piece_closure *) value_computed_closure (value);
840 int validity = (check_for == DWARF_VALUE_MEMORY
841 || check_for == DWARF_VALUE_IMPLICIT_POINTER);
843 bit_offset += 8 * value_offset (value);
844 if (value_bitsize (value))
845 bit_offset += value_bitpos (value);
847 for (i = 0; i < c->n_pieces && bit_length > 0; i++)
849 struct dwarf_expr_piece *p = &c->pieces[i];
850 size_t this_size_bits = p->size;
854 if (bit_offset >= this_size_bits)
856 bit_offset -= this_size_bits;
860 bit_length -= this_size_bits - bit_offset;
864 bit_length -= this_size_bits;
866 if (check_for == DWARF_VALUE_IMPLICIT_POINTER)
868 if (p->location != DWARF_VALUE_IMPLICIT_POINTER)
871 else if (p->location == DWARF_VALUE_OPTIMIZED_OUT
872 || p->location == DWARF_VALUE_IMPLICIT_POINTER)
888 check_pieced_value_validity (const struct value *value, int bit_offset,
891 return check_pieced_value_bits (value, bit_offset, bit_length,
896 check_pieced_value_invalid (const struct value *value)
898 return check_pieced_value_bits (value, 0,
899 8 * TYPE_LENGTH (value_type (value)),
900 DWARF_VALUE_OPTIMIZED_OUT);
903 /* An implementation of an lval_funcs method to see whether a value is
904 a synthetic pointer. */
907 check_pieced_synthetic_pointer (const struct value *value, int bit_offset,
910 return check_pieced_value_bits (value, bit_offset, bit_length,
911 DWARF_VALUE_IMPLICIT_POINTER);
914 /* A wrapper function for get_frame_address_in_block. */
917 get_frame_address_in_block_wrapper (void *baton)
919 return get_frame_address_in_block (baton);
922 /* An implementation of an lval_funcs method to indirect through a
923 pointer. This handles the synthetic pointer case when needed. */
925 static struct value *
926 indirect_pieced_value (struct value *value)
928 struct piece_closure *c
929 = (struct piece_closure *) value_computed_closure (value);
931 struct frame_info *frame;
932 struct dwarf2_locexpr_baton baton;
933 int i, bit_offset, bit_length;
934 struct dwarf_expr_piece *piece = NULL;
935 struct value *result;
938 type = value_type (value);
939 if (TYPE_CODE (type) != TYPE_CODE_PTR)
942 bit_length = 8 * TYPE_LENGTH (type);
943 bit_offset = 8 * value_offset (value);
944 if (value_bitsize (value))
945 bit_offset += value_bitpos (value);
947 for (i = 0; i < c->n_pieces && bit_length > 0; i++)
949 struct dwarf_expr_piece *p = &c->pieces[i];
950 size_t this_size_bits = p->size;
954 if (bit_offset >= this_size_bits)
956 bit_offset -= this_size_bits;
960 bit_length -= this_size_bits - bit_offset;
964 bit_length -= this_size_bits;
966 if (p->location != DWARF_VALUE_IMPLICIT_POINTER)
970 error (_("Invalid use of DW_OP_GNU_implicit_pointer"));
976 frame = get_selected_frame (_("No frame selected."));
977 byte_offset = value_as_address (value);
979 baton = dwarf2_fetch_die_location_block (piece->v.ptr.die, c->per_cu,
980 get_frame_address_in_block_wrapper,
983 result = dwarf2_evaluate_loc_desc_full (TYPE_TARGET_TYPE (type), frame,
984 baton.data, baton.size, baton.per_cu,
991 copy_pieced_value_closure (const struct value *v)
993 struct piece_closure *c
994 = (struct piece_closure *) value_computed_closure (v);
1001 free_pieced_value_closure (struct value *v)
1003 struct piece_closure *c
1004 = (struct piece_closure *) value_computed_closure (v);
1014 /* Functions for accessing a variable described by DW_OP_piece. */
1015 static struct lval_funcs pieced_value_funcs = {
1018 check_pieced_value_validity,
1019 check_pieced_value_invalid,
1020 indirect_pieced_value,
1021 check_pieced_synthetic_pointer,
1022 copy_pieced_value_closure,
1023 free_pieced_value_closure
1026 /* Helper function which throws an error if a synthetic pointer is
1030 invalid_synthetic_pointer (void)
1032 error (_("access outside bounds of object "
1033 "referenced via synthetic pointer"));
1036 /* Evaluate a location description, starting at DATA and with length
1037 SIZE, to find the current location of variable of TYPE in the
1038 context of FRAME. BYTE_OFFSET is applied after the contents are
1041 static struct value *
1042 dwarf2_evaluate_loc_desc_full (struct type *type, struct frame_info *frame,
1043 const gdb_byte *data, unsigned short size,
1044 struct dwarf2_per_cu_data *per_cu,
1045 LONGEST byte_offset)
1047 struct value *retval;
1048 struct dwarf_expr_baton baton;
1049 struct dwarf_expr_context *ctx;
1050 struct cleanup *old_chain;
1051 struct objfile *objfile = dwarf2_per_cu_objfile (per_cu);
1053 if (byte_offset < 0)
1054 invalid_synthetic_pointer ();
1058 retval = allocate_value (type);
1059 VALUE_LVAL (retval) = not_lval;
1060 set_value_optimized_out (retval, 1);
1064 baton.frame = frame;
1065 baton.per_cu = per_cu;
1067 ctx = new_dwarf_expr_context ();
1068 old_chain = make_cleanup_free_dwarf_expr_context (ctx);
1070 ctx->gdbarch = get_objfile_arch (objfile);
1071 ctx->addr_size = dwarf2_per_cu_addr_size (per_cu);
1072 ctx->offset = dwarf2_per_cu_text_offset (per_cu);
1073 ctx->baton = &baton;
1074 ctx->read_reg = dwarf_expr_read_reg;
1075 ctx->read_mem = dwarf_expr_read_mem;
1076 ctx->get_frame_base = dwarf_expr_frame_base;
1077 ctx->get_frame_cfa = dwarf_expr_frame_cfa;
1078 ctx->get_frame_pc = dwarf_expr_frame_pc;
1079 ctx->get_tls_address = dwarf_expr_tls_address;
1080 ctx->dwarf_call = dwarf_expr_dwarf_call;
1082 dwarf_expr_eval (ctx, data, size);
1083 if (ctx->num_pieces > 0)
1085 struct piece_closure *c;
1086 struct frame_id frame_id = get_frame_id (frame);
1087 ULONGEST bit_size = 0;
1090 for (i = 0; i < ctx->num_pieces; ++i)
1091 bit_size += ctx->pieces[i].size;
1092 if (8 * (byte_offset + TYPE_LENGTH (type)) > bit_size)
1093 invalid_synthetic_pointer ();
1095 c = allocate_piece_closure (per_cu, ctx->num_pieces, ctx->pieces,
1097 retval = allocate_computed_value (type, &pieced_value_funcs, c);
1098 VALUE_FRAME_ID (retval) = frame_id;
1099 set_value_offset (retval, byte_offset);
1103 switch (ctx->location)
1105 case DWARF_VALUE_REGISTER:
1107 struct gdbarch *arch = get_frame_arch (frame);
1108 ULONGEST dwarf_regnum = dwarf_expr_fetch (ctx, 0);
1109 int gdb_regnum = gdbarch_dwarf2_reg_to_regnum (arch, dwarf_regnum);
1111 if (byte_offset != 0)
1112 error (_("cannot use offset on synthetic pointer to register"));
1113 if (gdb_regnum != -1)
1114 retval = value_from_register (type, gdb_regnum, frame);
1116 error (_("Unable to access DWARF register number %s"),
1117 paddress (arch, dwarf_regnum));
1121 case DWARF_VALUE_MEMORY:
1123 CORE_ADDR address = dwarf_expr_fetch_address (ctx, 0);
1124 int in_stack_memory = dwarf_expr_fetch_in_stack_memory (ctx, 0);
1126 retval = allocate_value (type);
1127 VALUE_LVAL (retval) = lval_memory;
1128 set_value_lazy (retval, 1);
1129 if (in_stack_memory)
1130 set_value_stack (retval, 1);
1131 set_value_address (retval, address + byte_offset);
1135 case DWARF_VALUE_STACK:
1137 ULONGEST value = dwarf_expr_fetch (ctx, 0);
1138 bfd_byte *contents, *tem;
1139 size_t n = ctx->addr_size;
1141 if (byte_offset + TYPE_LENGTH (type) > n)
1142 invalid_synthetic_pointer ();
1145 store_unsigned_integer (tem, n,
1146 gdbarch_byte_order (ctx->gdbarch),
1152 retval = allocate_value (type);
1153 contents = value_contents_raw (retval);
1154 if (n > TYPE_LENGTH (type))
1155 n = TYPE_LENGTH (type);
1156 memcpy (contents, tem, n);
1160 case DWARF_VALUE_LITERAL:
1163 const bfd_byte *data;
1164 size_t n = ctx->len;
1166 if (byte_offset + TYPE_LENGTH (type) > n)
1167 invalid_synthetic_pointer ();
1169 retval = allocate_value (type);
1170 contents = value_contents_raw (retval);
1172 data = ctx->data + byte_offset;
1175 if (n > TYPE_LENGTH (type))
1176 n = TYPE_LENGTH (type);
1177 memcpy (contents, data, n);
1181 /* DWARF_VALUE_IMPLICIT_POINTER was converted to a pieced
1182 operation by execute_stack_op. */
1183 case DWARF_VALUE_IMPLICIT_POINTER:
1184 /* DWARF_VALUE_OPTIMIZED_OUT can't occur in this context --
1185 it can only be encountered when making a piece. */
1186 case DWARF_VALUE_OPTIMIZED_OUT:
1188 internal_error (__FILE__, __LINE__, _("invalid location type"));
1192 set_value_initialized (retval, ctx->initialized);
1194 do_cleanups (old_chain);
1199 /* The exported interface to dwarf2_evaluate_loc_desc_full; it always
1200 passes 0 as the byte_offset. */
1203 dwarf2_evaluate_loc_desc (struct type *type, struct frame_info *frame,
1204 const gdb_byte *data, unsigned short size,
1205 struct dwarf2_per_cu_data *per_cu)
1207 return dwarf2_evaluate_loc_desc_full (type, frame, data, size, per_cu, 0);
1211 /* Helper functions and baton for dwarf2_loc_desc_needs_frame. */
1213 struct needs_frame_baton
1216 struct dwarf2_per_cu_data *per_cu;
1219 /* Reads from registers do require a frame. */
1221 needs_frame_read_reg (void *baton, int regnum)
1223 struct needs_frame_baton *nf_baton = baton;
1225 nf_baton->needs_frame = 1;
1229 /* Reads from memory do not require a frame. */
1231 needs_frame_read_mem (void *baton, gdb_byte *buf, CORE_ADDR addr, size_t len)
1233 memset (buf, 0, len);
1236 /* Frame-relative accesses do require a frame. */
1238 needs_frame_frame_base (void *baton, const gdb_byte **start, size_t * length)
1240 static gdb_byte lit0 = DW_OP_lit0;
1241 struct needs_frame_baton *nf_baton = baton;
1246 nf_baton->needs_frame = 1;
1249 /* CFA accesses require a frame. */
1252 needs_frame_frame_cfa (void *baton)
1254 struct needs_frame_baton *nf_baton = baton;
1256 nf_baton->needs_frame = 1;
1260 /* Thread-local accesses do require a frame. */
1262 needs_frame_tls_address (void *baton, CORE_ADDR offset)
1264 struct needs_frame_baton *nf_baton = baton;
1266 nf_baton->needs_frame = 1;
1270 /* Helper interface of per_cu_dwarf_call for dwarf2_loc_desc_needs_frame. */
1273 needs_frame_dwarf_call (struct dwarf_expr_context *ctx, size_t die_offset)
1275 struct needs_frame_baton *nf_baton = ctx->baton;
1277 return per_cu_dwarf_call (ctx, die_offset, nf_baton->per_cu,
1278 ctx->get_frame_pc, ctx->baton);
1281 /* Return non-zero iff the location expression at DATA (length SIZE)
1282 requires a frame to evaluate. */
1285 dwarf2_loc_desc_needs_frame (const gdb_byte *data, unsigned short size,
1286 struct dwarf2_per_cu_data *per_cu)
1288 struct needs_frame_baton baton;
1289 struct dwarf_expr_context *ctx;
1291 struct cleanup *old_chain;
1292 struct objfile *objfile = dwarf2_per_cu_objfile (per_cu);
1294 baton.needs_frame = 0;
1295 baton.per_cu = per_cu;
1297 ctx = new_dwarf_expr_context ();
1298 old_chain = make_cleanup_free_dwarf_expr_context (ctx);
1300 ctx->gdbarch = get_objfile_arch (objfile);
1301 ctx->addr_size = dwarf2_per_cu_addr_size (per_cu);
1302 ctx->offset = dwarf2_per_cu_text_offset (per_cu);
1303 ctx->baton = &baton;
1304 ctx->read_reg = needs_frame_read_reg;
1305 ctx->read_mem = needs_frame_read_mem;
1306 ctx->get_frame_base = needs_frame_frame_base;
1307 ctx->get_frame_cfa = needs_frame_frame_cfa;
1308 ctx->get_frame_pc = needs_frame_frame_cfa;
1309 ctx->get_tls_address = needs_frame_tls_address;
1310 ctx->dwarf_call = needs_frame_dwarf_call;
1312 dwarf_expr_eval (ctx, data, size);
1314 in_reg = ctx->location == DWARF_VALUE_REGISTER;
1316 if (ctx->num_pieces > 0)
1320 /* If the location has several pieces, and any of them are in
1321 registers, then we will need a frame to fetch them from. */
1322 for (i = 0; i < ctx->num_pieces; i++)
1323 if (ctx->pieces[i].location == DWARF_VALUE_REGISTER)
1327 do_cleanups (old_chain);
1329 return baton.needs_frame || in_reg;
1332 /* A helper function that throws an unimplemented error mentioning a
1333 given DWARF operator. */
1336 unimplemented (unsigned int op)
1338 error (_("DWARF operator %s cannot be translated to an agent expression"),
1339 dwarf_stack_op_name (op, 1));
1342 /* A helper function to convert a DWARF register to an arch register.
1343 ARCH is the architecture.
1344 DWARF_REG is the register.
1345 This will throw an exception if the DWARF register cannot be
1346 translated to an architecture register. */
1349 translate_register (struct gdbarch *arch, int dwarf_reg)
1351 int reg = gdbarch_dwarf2_reg_to_regnum (arch, dwarf_reg);
1353 error (_("Unable to access DWARF register number %d"), dwarf_reg);
1357 /* A helper function that emits an access to memory. ARCH is the
1358 target architecture. EXPR is the expression which we are building.
1359 NBITS is the number of bits we want to read. This emits the
1360 opcodes needed to read the memory and then extract the desired
1364 access_memory (struct gdbarch *arch, struct agent_expr *expr, ULONGEST nbits)
1366 ULONGEST nbytes = (nbits + 7) / 8;
1368 gdb_assert (nbits > 0 && nbits <= sizeof (LONGEST));
1371 ax_trace_quick (expr, nbytes);
1374 ax_simple (expr, aop_ref8);
1375 else if (nbits <= 16)
1376 ax_simple (expr, aop_ref16);
1377 else if (nbits <= 32)
1378 ax_simple (expr, aop_ref32);
1380 ax_simple (expr, aop_ref64);
1382 /* If we read exactly the number of bytes we wanted, we're done. */
1383 if (8 * nbytes == nbits)
1386 if (gdbarch_bits_big_endian (arch))
1388 /* On a bits-big-endian machine, we want the high-order
1390 ax_const_l (expr, 8 * nbytes - nbits);
1391 ax_simple (expr, aop_rsh_unsigned);
1395 /* On a bits-little-endian box, we want the low-order NBITS. */
1396 ax_zero_ext (expr, nbits);
1400 /* A helper function to return the frame's PC. */
1403 get_ax_pc (void *baton)
1405 struct agent_expr *expr = baton;
1410 /* Compile a DWARF location expression to an agent expression.
1412 EXPR is the agent expression we are building.
1413 LOC is the agent value we modify.
1414 ARCH is the architecture.
1415 ADDR_SIZE is the size of addresses, in bytes.
1416 OP_PTR is the start of the location expression.
1417 OP_END is one past the last byte of the location expression.
1419 This will throw an exception for various kinds of errors -- for
1420 example, if the expression cannot be compiled, or if the expression
1424 compile_dwarf_to_ax (struct agent_expr *expr, struct axs_value *loc,
1425 struct gdbarch *arch, unsigned int addr_size,
1426 const gdb_byte *op_ptr, const gdb_byte *op_end,
1427 struct dwarf2_per_cu_data *per_cu)
1429 struct cleanup *cleanups;
1431 VEC(int) *dw_labels = NULL, *patches = NULL;
1432 const gdb_byte * const base = op_ptr;
1433 const gdb_byte *previous_piece = op_ptr;
1434 enum bfd_endian byte_order = gdbarch_byte_order (arch);
1435 ULONGEST bits_collected = 0;
1436 unsigned int addr_size_bits = 8 * addr_size;
1437 int bits_big_endian = gdbarch_bits_big_endian (arch);
1439 offsets = xmalloc ((op_end - op_ptr) * sizeof (int));
1440 cleanups = make_cleanup (xfree, offsets);
1442 for (i = 0; i < op_end - op_ptr; ++i)
1445 make_cleanup (VEC_cleanup (int), &dw_labels);
1446 make_cleanup (VEC_cleanup (int), &patches);
1448 /* By default we are making an address. */
1449 loc->kind = axs_lvalue_memory;
1451 while (op_ptr < op_end)
1453 enum dwarf_location_atom op = *op_ptr;
1454 ULONGEST uoffset, reg;
1458 offsets[op_ptr - base] = expr->len;
1461 /* Our basic approach to code generation is to map DWARF
1462 operations directly to AX operations. However, there are
1465 First, DWARF works on address-sized units, but AX always uses
1466 LONGEST. For most operations we simply ignore this
1467 difference; instead we generate sign extensions as needed
1468 before division and comparison operations. It would be nice
1469 to omit the sign extensions, but there is no way to determine
1470 the size of the target's LONGEST. (This code uses the size
1471 of the host LONGEST in some cases -- that is a bug but it is
1474 Second, some DWARF operations cannot be translated to AX.
1475 For these we simply fail. See
1476 http://sourceware.org/bugzilla/show_bug.cgi?id=11662. */
1511 ax_const_l (expr, op - DW_OP_lit0);
1515 uoffset = extract_unsigned_integer (op_ptr, addr_size, byte_order);
1516 op_ptr += addr_size;
1517 /* Some versions of GCC emit DW_OP_addr before
1518 DW_OP_GNU_push_tls_address. In this case the value is an
1519 index, not an address. We don't support things like
1520 branching between the address and the TLS op. */
1521 if (op_ptr >= op_end || *op_ptr != DW_OP_GNU_push_tls_address)
1522 uoffset += dwarf2_per_cu_text_offset (per_cu);
1523 ax_const_l (expr, uoffset);
1527 ax_const_l (expr, extract_unsigned_integer (op_ptr, 1, byte_order));
1531 ax_const_l (expr, extract_signed_integer (op_ptr, 1, byte_order));
1535 ax_const_l (expr, extract_unsigned_integer (op_ptr, 2, byte_order));
1539 ax_const_l (expr, extract_signed_integer (op_ptr, 2, byte_order));
1543 ax_const_l (expr, extract_unsigned_integer (op_ptr, 4, byte_order));
1547 ax_const_l (expr, extract_signed_integer (op_ptr, 4, byte_order));
1551 ax_const_l (expr, extract_unsigned_integer (op_ptr, 8, byte_order));
1555 ax_const_l (expr, extract_signed_integer (op_ptr, 8, byte_order));
1559 op_ptr = read_uleb128 (op_ptr, op_end, &uoffset);
1560 ax_const_l (expr, uoffset);
1563 op_ptr = read_sleb128 (op_ptr, op_end, &offset);
1564 ax_const_l (expr, offset);
1599 dwarf_expr_require_composition (op_ptr, op_end, "DW_OP_regx");
1600 loc->u.reg = translate_register (arch, op - DW_OP_reg0);
1601 loc->kind = axs_lvalue_register;
1605 op_ptr = read_uleb128 (op_ptr, op_end, ®);
1606 dwarf_expr_require_composition (op_ptr, op_end, "DW_OP_regx");
1607 loc->u.reg = translate_register (arch, reg);
1608 loc->kind = axs_lvalue_register;
1611 case DW_OP_implicit_value:
1615 op_ptr = read_uleb128 (op_ptr, op_end, &len);
1616 if (op_ptr + len > op_end)
1617 error (_("DW_OP_implicit_value: too few bytes available."));
1618 if (len > sizeof (ULONGEST))
1619 error (_("Cannot translate DW_OP_implicit_value of %d bytes"),
1622 ax_const_l (expr, extract_unsigned_integer (op_ptr, len,
1625 dwarf_expr_require_composition (op_ptr, op_end,
1626 "DW_OP_implicit_value");
1628 loc->kind = axs_rvalue;
1632 case DW_OP_stack_value:
1633 dwarf_expr_require_composition (op_ptr, op_end, "DW_OP_stack_value");
1634 loc->kind = axs_rvalue;
1669 op_ptr = read_sleb128 (op_ptr, op_end, &offset);
1670 i = translate_register (arch, op - DW_OP_breg0);
1674 ax_const_l (expr, offset);
1675 ax_simple (expr, aop_add);
1680 op_ptr = read_uleb128 (op_ptr, op_end, ®);
1681 op_ptr = read_sleb128 (op_ptr, op_end, &offset);
1682 i = translate_register (arch, reg);
1686 ax_const_l (expr, offset);
1687 ax_simple (expr, aop_add);
1693 const gdb_byte *datastart;
1695 unsigned int before_stack_len;
1697 struct symbol *framefunc;
1698 LONGEST base_offset = 0;
1700 b = block_for_pc (expr->scope);
1703 error (_("No block found for address"));
1705 framefunc = block_linkage_function (b);
1708 error (_("No function found for block"));
1710 dwarf_expr_frame_base_1 (framefunc, expr->scope,
1711 &datastart, &datalen);
1713 op_ptr = read_sleb128 (op_ptr, op_end, &offset);
1714 compile_dwarf_to_ax (expr, loc, arch, addr_size, datastart,
1715 datastart + datalen, per_cu);
1719 ax_const_l (expr, offset);
1720 ax_simple (expr, aop_add);
1723 loc->kind = axs_lvalue_memory;
1728 ax_simple (expr, aop_dup);
1732 ax_simple (expr, aop_pop);
1741 ax_simple (expr, aop_swap);
1745 /* We can't directly support DW_OP_over, but GCC emits it as
1746 part of a sequence to implement signed modulus. As a
1747 hack, we recognize this sequence. Note that if GCC ever
1748 generates a branch to the middle of this sequence, then
1749 we will die somehow. */
1750 if (op_end - op_ptr >= 4
1751 && op_ptr[0] == DW_OP_over
1752 && op_ptr[1] == DW_OP_div
1753 && op_ptr[2] == DW_OP_mul
1754 && op_ptr[3] == DW_OP_minus)
1756 /* Sign extend the operands. */
1757 ax_ext (expr, addr_size_bits);
1758 ax_simple (expr, aop_swap);
1759 ax_ext (expr, addr_size_bits);
1760 ax_simple (expr, aop_swap);
1761 ax_simple (expr, aop_rem_signed);
1773 case DW_OP_deref_size:
1777 if (op == DW_OP_deref_size)
1785 ax_simple (expr, aop_ref8);
1788 ax_simple (expr, aop_ref16);
1791 ax_simple (expr, aop_ref32);
1794 ax_simple (expr, aop_ref64);
1797 error (_("Unsupported size %d in %s"),
1798 size, dwarf_stack_op_name (op, 1));
1804 /* Sign extend the operand. */
1805 ax_ext (expr, addr_size_bits);
1806 ax_simple (expr, aop_dup);
1807 ax_const_l (expr, 0);
1808 ax_simple (expr, aop_less_signed);
1809 ax_simple (expr, aop_log_not);
1810 i = ax_goto (expr, aop_if_goto);
1811 /* We have to emit 0 - X. */
1812 ax_const_l (expr, 0);
1813 ax_simple (expr, aop_swap);
1814 ax_simple (expr, aop_sub);
1815 ax_label (expr, i, expr->len);
1819 /* No need to sign extend here. */
1820 ax_const_l (expr, 0);
1821 ax_simple (expr, aop_swap);
1822 ax_simple (expr, aop_sub);
1826 /* Sign extend the operand. */
1827 ax_ext (expr, addr_size_bits);
1828 ax_simple (expr, aop_bit_not);
1831 case DW_OP_plus_uconst:
1832 op_ptr = read_uleb128 (op_ptr, op_end, ®);
1833 /* It would be really weird to emit `DW_OP_plus_uconst 0',
1834 but we micro-optimize anyhow. */
1837 ax_const_l (expr, reg);
1838 ax_simple (expr, aop_add);
1843 ax_simple (expr, aop_bit_and);
1847 /* Sign extend the operands. */
1848 ax_ext (expr, addr_size_bits);
1849 ax_simple (expr, aop_swap);
1850 ax_ext (expr, addr_size_bits);
1851 ax_simple (expr, aop_swap);
1852 ax_simple (expr, aop_div_signed);
1856 ax_simple (expr, aop_sub);
1860 ax_simple (expr, aop_rem_unsigned);
1864 ax_simple (expr, aop_mul);
1868 ax_simple (expr, aop_bit_or);
1872 ax_simple (expr, aop_add);
1876 ax_simple (expr, aop_lsh);
1880 ax_simple (expr, aop_rsh_unsigned);
1884 ax_simple (expr, aop_rsh_signed);
1888 ax_simple (expr, aop_bit_xor);
1892 /* Sign extend the operands. */
1893 ax_ext (expr, addr_size_bits);
1894 ax_simple (expr, aop_swap);
1895 ax_ext (expr, addr_size_bits);
1896 /* Note no swap here: A <= B is !(B < A). */
1897 ax_simple (expr, aop_less_signed);
1898 ax_simple (expr, aop_log_not);
1902 /* Sign extend the operands. */
1903 ax_ext (expr, addr_size_bits);
1904 ax_simple (expr, aop_swap);
1905 ax_ext (expr, addr_size_bits);
1906 ax_simple (expr, aop_swap);
1907 /* A >= B is !(A < B). */
1908 ax_simple (expr, aop_less_signed);
1909 ax_simple (expr, aop_log_not);
1913 /* Sign extend the operands. */
1914 ax_ext (expr, addr_size_bits);
1915 ax_simple (expr, aop_swap);
1916 ax_ext (expr, addr_size_bits);
1917 /* No need for a second swap here. */
1918 ax_simple (expr, aop_equal);
1922 /* Sign extend the operands. */
1923 ax_ext (expr, addr_size_bits);
1924 ax_simple (expr, aop_swap);
1925 ax_ext (expr, addr_size_bits);
1926 ax_simple (expr, aop_swap);
1927 ax_simple (expr, aop_less_signed);
1931 /* Sign extend the operands. */
1932 ax_ext (expr, addr_size_bits);
1933 ax_simple (expr, aop_swap);
1934 ax_ext (expr, addr_size_bits);
1935 /* Note no swap here: A > B is B < A. */
1936 ax_simple (expr, aop_less_signed);
1940 /* Sign extend the operands. */
1941 ax_ext (expr, addr_size_bits);
1942 ax_simple (expr, aop_swap);
1943 ax_ext (expr, addr_size_bits);
1944 /* No need for a swap here. */
1945 ax_simple (expr, aop_equal);
1946 ax_simple (expr, aop_log_not);
1949 case DW_OP_call_frame_cfa:
1953 case DW_OP_GNU_push_tls_address:
1958 offset = extract_signed_integer (op_ptr, 2, byte_order);
1960 i = ax_goto (expr, aop_goto);
1961 VEC_safe_push (int, dw_labels, op_ptr + offset - base);
1962 VEC_safe_push (int, patches, i);
1966 offset = extract_signed_integer (op_ptr, 2, byte_order);
1968 /* Zero extend the operand. */
1969 ax_zero_ext (expr, addr_size_bits);
1970 i = ax_goto (expr, aop_if_goto);
1971 VEC_safe_push (int, dw_labels, op_ptr + offset - base);
1972 VEC_safe_push (int, patches, i);
1979 case DW_OP_bit_piece:
1981 ULONGEST size, offset;
1983 if (op_ptr - 1 == previous_piece)
1984 error (_("Cannot translate empty pieces to agent expressions"));
1985 previous_piece = op_ptr - 1;
1987 op_ptr = read_uleb128 (op_ptr, op_end, &size);
1988 if (op == DW_OP_piece)
1994 op_ptr = read_uleb128 (op_ptr, op_end, &offset);
1996 if (bits_collected + size > 8 * sizeof (LONGEST))
1997 error (_("Expression pieces exceed word size"));
1999 /* Access the bits. */
2002 case axs_lvalue_register:
2003 ax_reg (expr, loc->u.reg);
2006 case axs_lvalue_memory:
2007 /* Offset the pointer, if needed. */
2010 ax_const_l (expr, offset / 8);
2011 ax_simple (expr, aop_add);
2014 access_memory (arch, expr, size);
2018 /* For a bits-big-endian target, shift up what we already
2019 have. For a bits-little-endian target, shift up the
2020 new data. Note that there is a potential bug here if
2021 the DWARF expression leaves multiple values on the
2023 if (bits_collected > 0)
2025 if (bits_big_endian)
2027 ax_simple (expr, aop_swap);
2028 ax_const_l (expr, size);
2029 ax_simple (expr, aop_lsh);
2030 /* We don't need a second swap here, because
2031 aop_bit_or is symmetric. */
2035 ax_const_l (expr, size);
2036 ax_simple (expr, aop_lsh);
2038 ax_simple (expr, aop_bit_or);
2041 bits_collected += size;
2042 loc->kind = axs_rvalue;
2046 case DW_OP_GNU_uninit:
2052 struct dwarf2_locexpr_baton block;
2053 int size = (op == DW_OP_call2 ? 2 : 4);
2055 uoffset = extract_unsigned_integer (op_ptr, size, byte_order);
2058 block = dwarf2_fetch_die_location_block (uoffset, per_cu,
2061 /* DW_OP_call_ref is currently not supported. */
2062 gdb_assert (block.per_cu == per_cu);
2064 compile_dwarf_to_ax (expr, loc, arch, addr_size,
2065 block.data, block.data + block.size,
2070 case DW_OP_call_ref:
2074 error (_("Unhandled dwarf expression opcode 0x%x"), op);
2078 /* Patch all the branches we emitted. */
2079 for (i = 0; i < VEC_length (int, patches); ++i)
2081 int targ = offsets[VEC_index (int, dw_labels, i)];
2083 internal_error (__FILE__, __LINE__, _("invalid label"));
2084 ax_label (expr, VEC_index (int, patches, i), targ);
2087 do_cleanups (cleanups);
2091 /* Return the value of SYMBOL in FRAME using the DWARF-2 expression
2092 evaluator to calculate the location. */
2093 static struct value *
2094 locexpr_read_variable (struct symbol *symbol, struct frame_info *frame)
2096 struct dwarf2_locexpr_baton *dlbaton = SYMBOL_LOCATION_BATON (symbol);
2099 val = dwarf2_evaluate_loc_desc (SYMBOL_TYPE (symbol), frame, dlbaton->data,
2100 dlbaton->size, dlbaton->per_cu);
2105 /* Return non-zero iff we need a frame to evaluate SYMBOL. */
2107 locexpr_read_needs_frame (struct symbol *symbol)
2109 struct dwarf2_locexpr_baton *dlbaton = SYMBOL_LOCATION_BATON (symbol);
2111 return dwarf2_loc_desc_needs_frame (dlbaton->data, dlbaton->size,
2115 /* Return true if DATA points to the end of a piece. END is one past
2116 the last byte in the expression. */
2119 piece_end_p (const gdb_byte *data, const gdb_byte *end)
2121 return data == end || data[0] == DW_OP_piece || data[0] == DW_OP_bit_piece;
2124 /* Nicely describe a single piece of a location, returning an updated
2125 position in the bytecode sequence. This function cannot recognize
2126 all locations; if a location is not recognized, it simply returns
2129 static const gdb_byte *
2130 locexpr_describe_location_piece (struct symbol *symbol, struct ui_file *stream,
2131 CORE_ADDR addr, struct objfile *objfile,
2132 const gdb_byte *data, const gdb_byte *end,
2133 unsigned int addr_size)
2135 struct gdbarch *gdbarch = get_objfile_arch (objfile);
2138 if (data[0] >= DW_OP_reg0 && data[0] <= DW_OP_reg31)
2140 regno = gdbarch_dwarf2_reg_to_regnum (gdbarch, data[0] - DW_OP_reg0);
2141 fprintf_filtered (stream, _("a variable in $%s"),
2142 gdbarch_register_name (gdbarch, regno));
2145 else if (data[0] == DW_OP_regx)
2149 data = read_uleb128 (data + 1, end, ®);
2150 regno = gdbarch_dwarf2_reg_to_regnum (gdbarch, reg);
2151 fprintf_filtered (stream, _("a variable in $%s"),
2152 gdbarch_register_name (gdbarch, regno));
2154 else if (data[0] == DW_OP_fbreg)
2157 struct symbol *framefunc;
2159 LONGEST frame_offset;
2160 const gdb_byte *base_data, *new_data, *save_data = data;
2162 LONGEST base_offset = 0;
2164 new_data = read_sleb128 (data + 1, end, &frame_offset);
2165 if (!piece_end_p (new_data, end))
2169 b = block_for_pc (addr);
2172 error (_("No block found for address for symbol \"%s\"."),
2173 SYMBOL_PRINT_NAME (symbol));
2175 framefunc = block_linkage_function (b);
2178 error (_("No function found for block for symbol \"%s\"."),
2179 SYMBOL_PRINT_NAME (symbol));
2181 dwarf_expr_frame_base_1 (framefunc, addr, &base_data, &base_size);
2183 if (base_data[0] >= DW_OP_breg0 && base_data[0] <= DW_OP_breg31)
2185 const gdb_byte *buf_end;
2187 frame_reg = base_data[0] - DW_OP_breg0;
2188 buf_end = read_sleb128 (base_data + 1,
2189 base_data + base_size, &base_offset);
2190 if (buf_end != base_data + base_size)
2191 error (_("Unexpected opcode after "
2192 "DW_OP_breg%u for symbol \"%s\"."),
2193 frame_reg, SYMBOL_PRINT_NAME (symbol));
2195 else if (base_data[0] >= DW_OP_reg0 && base_data[0] <= DW_OP_reg31)
2197 /* The frame base is just the register, with no offset. */
2198 frame_reg = base_data[0] - DW_OP_reg0;
2203 /* We don't know what to do with the frame base expression,
2204 so we can't trace this variable; give up. */
2208 regno = gdbarch_dwarf2_reg_to_regnum (gdbarch, frame_reg);
2210 fprintf_filtered (stream,
2211 _("a variable at frame base reg $%s offset %s+%s"),
2212 gdbarch_register_name (gdbarch, regno),
2213 plongest (base_offset), plongest (frame_offset));
2215 else if (data[0] >= DW_OP_breg0 && data[0] <= DW_OP_breg31
2216 && piece_end_p (data, end))
2220 regno = gdbarch_dwarf2_reg_to_regnum (gdbarch, data[0] - DW_OP_breg0);
2222 data = read_sleb128 (data + 1, end, &offset);
2224 fprintf_filtered (stream,
2225 _("a variable at offset %s from base reg $%s"),
2227 gdbarch_register_name (gdbarch, regno));
2230 /* The location expression for a TLS variable looks like this (on a
2233 DW_AT_location : 10 byte block: 3 4 0 0 0 0 0 0 0 e0
2234 (DW_OP_addr: 4; DW_OP_GNU_push_tls_address)
2236 0x3 is the encoding for DW_OP_addr, which has an operand as long
2237 as the size of an address on the target machine (here is 8
2238 bytes). Note that more recent version of GCC emit DW_OP_const4u
2239 or DW_OP_const8u, depending on address size, rather than
2240 DW_OP_addr. 0xe0 is the encoding for
2241 DW_OP_GNU_push_tls_address. The operand represents the offset at
2242 which the variable is within the thread local storage. */
2244 else if (data + 1 + addr_size < end
2245 && (data[0] == DW_OP_addr
2246 || (addr_size == 4 && data[0] == DW_OP_const4u)
2247 || (addr_size == 8 && data[0] == DW_OP_const8u))
2248 && data[1 + addr_size] == DW_OP_GNU_push_tls_address
2249 && piece_end_p (data + 2 + addr_size, end))
2252 offset = extract_unsigned_integer (data + 1, addr_size,
2253 gdbarch_byte_order (gdbarch));
2255 fprintf_filtered (stream,
2256 _("a thread-local variable at offset 0x%s "
2257 "in the thread-local storage for `%s'"),
2258 phex_nz (offset, addr_size), objfile->name);
2260 data += 1 + addr_size + 1;
2262 else if (data[0] >= DW_OP_lit0
2263 && data[0] <= DW_OP_lit31
2265 && data[1] == DW_OP_stack_value)
2267 fprintf_filtered (stream, _("the constant %d"), data[0] - DW_OP_lit0);
2274 /* Disassemble an expression, stopping at the end of a piece or at the
2275 end of the expression. Returns a pointer to the next unread byte
2276 in the input expression. If ALL is nonzero, then this function
2277 will keep going until it reaches the end of the expression. */
2279 static const gdb_byte *
2280 disassemble_dwarf_expression (struct ui_file *stream,
2281 struct gdbarch *arch, unsigned int addr_size,
2283 const gdb_byte *data, const gdb_byte *end,
2286 const gdb_byte *start = data;
2288 fprintf_filtered (stream, _("a complex DWARF expression:\n"));
2292 || (data[0] != DW_OP_piece && data[0] != DW_OP_bit_piece)))
2294 enum dwarf_location_atom op = *data++;
2299 name = dwarf_stack_op_name (op, 0);
2302 error (_("Unrecognized DWARF opcode 0x%02x at %ld"),
2303 op, (long) (data - start));
2304 fprintf_filtered (stream, " % 4ld: %s", (long) (data - start), name);
2309 ul = extract_unsigned_integer (data, addr_size,
2310 gdbarch_byte_order (arch));
2312 fprintf_filtered (stream, " 0x%s", phex_nz (ul, addr_size));
2316 ul = extract_unsigned_integer (data, 1, gdbarch_byte_order (arch));
2318 fprintf_filtered (stream, " %s", pulongest (ul));
2321 l = extract_signed_integer (data, 1, gdbarch_byte_order (arch));
2323 fprintf_filtered (stream, " %s", plongest (l));
2326 ul = extract_unsigned_integer (data, 2, gdbarch_byte_order (arch));
2328 fprintf_filtered (stream, " %s", pulongest (ul));
2331 l = extract_signed_integer (data, 2, gdbarch_byte_order (arch));
2333 fprintf_filtered (stream, " %s", plongest (l));
2336 ul = extract_unsigned_integer (data, 4, gdbarch_byte_order (arch));
2338 fprintf_filtered (stream, " %s", pulongest (ul));
2341 l = extract_signed_integer (data, 4, gdbarch_byte_order (arch));
2343 fprintf_filtered (stream, " %s", plongest (l));
2346 ul = extract_unsigned_integer (data, 8, gdbarch_byte_order (arch));
2348 fprintf_filtered (stream, " %s", pulongest (ul));
2351 l = extract_signed_integer (data, 8, gdbarch_byte_order (arch));
2353 fprintf_filtered (stream, " %s", plongest (l));
2356 data = read_uleb128 (data, end, &ul);
2357 fprintf_filtered (stream, " %s", pulongest (ul));
2360 data = read_sleb128 (data, end, &l);
2361 fprintf_filtered (stream, " %s", plongest (l));
2396 fprintf_filtered (stream, " [$%s]",
2397 gdbarch_register_name (arch, op - DW_OP_reg0));
2401 data = read_uleb128 (data, end, &ul);
2402 fprintf_filtered (stream, " %s [$%s]", pulongest (ul),
2403 gdbarch_register_name (arch, (int) ul));
2406 case DW_OP_implicit_value:
2407 data = read_uleb128 (data, end, &ul);
2409 fprintf_filtered (stream, " %s", pulongest (ul));
2444 data = read_sleb128 (data, end, &ul);
2445 fprintf_filtered (stream, " %s [$%s]", pulongest (ul),
2446 gdbarch_register_name (arch, op - DW_OP_breg0));
2453 data = read_uleb128 (data, end, &ul);
2454 data = read_sleb128 (data, end, &offset);
2455 fprintf_filtered (stream, " register %s [$%s] offset %s",
2457 gdbarch_register_name (arch, (int) ul),
2458 pulongest (offset));
2463 data = read_sleb128 (data, end, &ul);
2464 fprintf_filtered (stream, " %s", pulongest (ul));
2467 case DW_OP_xderef_size:
2468 case DW_OP_deref_size:
2470 fprintf_filtered (stream, " %d", *data);
2474 case DW_OP_plus_uconst:
2475 data = read_uleb128 (data, end, &ul);
2476 fprintf_filtered (stream, " %s", pulongest (ul));
2480 l = extract_signed_integer (data, 2, gdbarch_byte_order (arch));
2482 fprintf_filtered (stream, " to %ld",
2483 (long) (data + l - start));
2487 l = extract_signed_integer (data, 2, gdbarch_byte_order (arch));
2489 fprintf_filtered (stream, " %ld",
2490 (long) (data + l - start));
2494 ul = extract_unsigned_integer (data, 2, gdbarch_byte_order (arch));
2496 fprintf_filtered (stream, " offset %s", phex_nz (ul, 2));
2500 ul = extract_unsigned_integer (data, 4, gdbarch_byte_order (arch));
2502 fprintf_filtered (stream, " offset %s", phex_nz (ul, 4));
2505 case DW_OP_call_ref:
2506 ul = extract_unsigned_integer (data, offset_size,
2507 gdbarch_byte_order (arch));
2508 data += offset_size;
2509 fprintf_filtered (stream, " offset %s", phex_nz (ul, offset_size));
2513 data = read_uleb128 (data, end, &ul);
2514 fprintf_filtered (stream, " %s (bytes)", pulongest (ul));
2517 case DW_OP_bit_piece:
2521 data = read_uleb128 (data, end, &ul);
2522 data = read_uleb128 (data, end, &offset);
2523 fprintf_filtered (stream, " size %s offset %s (bits)",
2524 pulongest (ul), pulongest (offset));
2528 case DW_OP_GNU_implicit_pointer:
2530 ul = extract_unsigned_integer (data, offset_size,
2531 gdbarch_byte_order (arch));
2532 data += offset_size;
2534 data = read_sleb128 (data, end, &l);
2536 fprintf_filtered (stream, " DIE %s offset %s",
2537 phex_nz (ul, offset_size),
2543 fprintf_filtered (stream, "\n");
2549 /* Describe a single location, which may in turn consist of multiple
2553 locexpr_describe_location_1 (struct symbol *symbol, CORE_ADDR addr,
2554 struct ui_file *stream,
2555 const gdb_byte *data, int size,
2556 struct objfile *objfile, unsigned int addr_size,
2559 const gdb_byte *end = data + size;
2560 int first_piece = 1, bad = 0;
2564 const gdb_byte *here = data;
2565 int disassemble = 1;
2570 fprintf_filtered (stream, _(", and "));
2572 if (!dwarf2_always_disassemble)
2574 data = locexpr_describe_location_piece (symbol, stream,
2576 data, end, addr_size);
2577 /* If we printed anything, or if we have an empty piece,
2578 then don't disassemble. */
2580 || data[0] == DW_OP_piece
2581 || data[0] == DW_OP_bit_piece)
2585 data = disassemble_dwarf_expression (stream,
2586 get_objfile_arch (objfile),
2587 addr_size, offset_size, data, end,
2588 dwarf2_always_disassemble);
2592 int empty = data == here;
2595 fprintf_filtered (stream, " ");
2596 if (data[0] == DW_OP_piece)
2600 data = read_uleb128 (data + 1, end, &bytes);
2603 fprintf_filtered (stream, _("an empty %s-byte piece"),
2606 fprintf_filtered (stream, _(" [%s-byte piece]"),
2609 else if (data[0] == DW_OP_bit_piece)
2611 ULONGEST bits, offset;
2613 data = read_uleb128 (data + 1, end, &bits);
2614 data = read_uleb128 (data, end, &offset);
2617 fprintf_filtered (stream,
2618 _("an empty %s-bit piece"),
2621 fprintf_filtered (stream,
2622 _(" [%s-bit piece, offset %s bits]"),
2623 pulongest (bits), pulongest (offset));
2633 if (bad || data > end)
2634 error (_("Corrupted DWARF2 expression for \"%s\"."),
2635 SYMBOL_PRINT_NAME (symbol));
2638 /* Print a natural-language description of SYMBOL to STREAM. This
2639 version is for a symbol with a single location. */
2642 locexpr_describe_location (struct symbol *symbol, CORE_ADDR addr,
2643 struct ui_file *stream)
2645 struct dwarf2_locexpr_baton *dlbaton = SYMBOL_LOCATION_BATON (symbol);
2646 struct objfile *objfile = dwarf2_per_cu_objfile (dlbaton->per_cu);
2647 unsigned int addr_size = dwarf2_per_cu_addr_size (dlbaton->per_cu);
2648 int offset_size = dwarf2_per_cu_offset_size (dlbaton->per_cu);
2650 locexpr_describe_location_1 (symbol, addr, stream,
2651 dlbaton->data, dlbaton->size,
2652 objfile, addr_size, offset_size);
2655 /* Describe the location of SYMBOL as an agent value in VALUE, generating
2656 any necessary bytecode in AX. */
2659 locexpr_tracepoint_var_ref (struct symbol *symbol, struct gdbarch *gdbarch,
2660 struct agent_expr *ax, struct axs_value *value)
2662 struct dwarf2_locexpr_baton *dlbaton = SYMBOL_LOCATION_BATON (symbol);
2663 unsigned int addr_size = dwarf2_per_cu_addr_size (dlbaton->per_cu);
2665 if (dlbaton->data == NULL || dlbaton->size == 0)
2666 value->optimized_out = 1;
2668 compile_dwarf_to_ax (ax, value, gdbarch, addr_size,
2669 dlbaton->data, dlbaton->data + dlbaton->size,
2673 /* The set of location functions used with the DWARF-2 expression
2675 const struct symbol_computed_ops dwarf2_locexpr_funcs = {
2676 locexpr_read_variable,
2677 locexpr_read_needs_frame,
2678 locexpr_describe_location,
2679 locexpr_tracepoint_var_ref
2683 /* Wrapper functions for location lists. These generally find
2684 the appropriate location expression and call something above. */
2686 /* Return the value of SYMBOL in FRAME using the DWARF-2 expression
2687 evaluator to calculate the location. */
2688 static struct value *
2689 loclist_read_variable (struct symbol *symbol, struct frame_info *frame)
2691 struct dwarf2_loclist_baton *dlbaton = SYMBOL_LOCATION_BATON (symbol);
2693 const gdb_byte *data;
2695 CORE_ADDR pc = frame ? get_frame_address_in_block (frame) : 0;
2697 data = dwarf2_find_location_expression (dlbaton, &size, pc);
2700 val = allocate_value (SYMBOL_TYPE (symbol));
2701 VALUE_LVAL (val) = not_lval;
2702 set_value_optimized_out (val, 1);
2705 val = dwarf2_evaluate_loc_desc (SYMBOL_TYPE (symbol), frame, data, size,
2711 /* Return non-zero iff we need a frame to evaluate SYMBOL. */
2713 loclist_read_needs_frame (struct symbol *symbol)
2715 /* If there's a location list, then assume we need to have a frame
2716 to choose the appropriate location expression. With tracking of
2717 global variables this is not necessarily true, but such tracking
2718 is disabled in GCC at the moment until we figure out how to
2724 /* Print a natural-language description of SYMBOL to STREAM. This
2725 version applies when there is a list of different locations, each
2726 with a specified address range. */
2729 loclist_describe_location (struct symbol *symbol, CORE_ADDR addr,
2730 struct ui_file *stream)
2732 struct dwarf2_loclist_baton *dlbaton = SYMBOL_LOCATION_BATON (symbol);
2733 CORE_ADDR low, high;
2734 const gdb_byte *loc_ptr, *buf_end;
2735 int length, first = 1;
2736 struct objfile *objfile = dwarf2_per_cu_objfile (dlbaton->per_cu);
2737 struct gdbarch *gdbarch = get_objfile_arch (objfile);
2738 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
2739 unsigned int addr_size = dwarf2_per_cu_addr_size (dlbaton->per_cu);
2740 int offset_size = dwarf2_per_cu_offset_size (dlbaton->per_cu);
2741 int signed_addr_p = bfd_get_sign_extend_vma (objfile->obfd);
2742 CORE_ADDR base_mask = ~(~(CORE_ADDR)1 << (addr_size * 8 - 1));
2743 /* Adjust base_address for relocatable objects. */
2744 CORE_ADDR base_offset = dwarf2_per_cu_text_offset (dlbaton->per_cu);
2745 CORE_ADDR base_address = dlbaton->base_address + base_offset;
2747 loc_ptr = dlbaton->data;
2748 buf_end = dlbaton->data + dlbaton->size;
2750 fprintf_filtered (stream, _("multi-location:\n"));
2752 /* Iterate through locations until we run out. */
2755 if (buf_end - loc_ptr < 2 * addr_size)
2756 error (_("Corrupted DWARF expression for symbol \"%s\"."),
2757 SYMBOL_PRINT_NAME (symbol));
2760 low = extract_signed_integer (loc_ptr, addr_size, byte_order);
2762 low = extract_unsigned_integer (loc_ptr, addr_size, byte_order);
2763 loc_ptr += addr_size;
2766 high = extract_signed_integer (loc_ptr, addr_size, byte_order);
2768 high = extract_unsigned_integer (loc_ptr, addr_size, byte_order);
2769 loc_ptr += addr_size;
2771 /* A base-address-selection entry. */
2772 if ((low & base_mask) == base_mask)
2774 base_address = high + base_offset;
2775 fprintf_filtered (stream, _(" Base address %s"),
2776 paddress (gdbarch, base_address));
2780 /* An end-of-list entry. */
2781 if (low == 0 && high == 0)
2784 /* Otherwise, a location expression entry. */
2785 low += base_address;
2786 high += base_address;
2788 length = extract_unsigned_integer (loc_ptr, 2, byte_order);
2791 /* (It would improve readability to print only the minimum
2792 necessary digits of the second number of the range.) */
2793 fprintf_filtered (stream, _(" Range %s-%s: "),
2794 paddress (gdbarch, low), paddress (gdbarch, high));
2796 /* Now describe this particular location. */
2797 locexpr_describe_location_1 (symbol, low, stream, loc_ptr, length,
2798 objfile, addr_size, offset_size);
2800 fprintf_filtered (stream, "\n");
2806 /* Describe the location of SYMBOL as an agent value in VALUE, generating
2807 any necessary bytecode in AX. */
2809 loclist_tracepoint_var_ref (struct symbol *symbol, struct gdbarch *gdbarch,
2810 struct agent_expr *ax, struct axs_value *value)
2812 struct dwarf2_loclist_baton *dlbaton = SYMBOL_LOCATION_BATON (symbol);
2813 const gdb_byte *data;
2815 unsigned int addr_size = dwarf2_per_cu_addr_size (dlbaton->per_cu);
2817 data = dwarf2_find_location_expression (dlbaton, &size, ax->scope);
2818 if (data == NULL || size == 0)
2819 value->optimized_out = 1;
2821 compile_dwarf_to_ax (ax, value, gdbarch, addr_size, data, data + size,
2825 /* The set of location functions used with the DWARF-2 expression
2826 evaluator and location lists. */
2827 const struct symbol_computed_ops dwarf2_loclist_funcs = {
2828 loclist_read_variable,
2829 loclist_read_needs_frame,
2830 loclist_describe_location,
2831 loclist_tracepoint_var_ref