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 per_cu_dwarf_call (ctx, die_offset, debaton->per_cu,
286 ctx->get_frame_pc, ctx->baton);
289 /* Callback function for dwarf2_evaluate_loc_desc. */
292 dwarf_expr_get_base_type (struct dwarf_expr_context *ctx, size_t die_offset)
294 struct dwarf_expr_baton *debaton = ctx->baton;
296 return dwarf2_get_die_type (die_offset, debaton->per_cu);
301 /* Reference count. */
304 /* The CU from which this closure's expression came. */
305 struct dwarf2_per_cu_data *per_cu;
307 /* The number of pieces used to describe this variable. */
310 /* The target address size, used only for DWARF_VALUE_STACK. */
313 /* The pieces themselves. */
314 struct dwarf_expr_piece *pieces;
317 /* Allocate a closure for a value formed from separately-described
320 static struct piece_closure *
321 allocate_piece_closure (struct dwarf2_per_cu_data *per_cu,
322 int n_pieces, struct dwarf_expr_piece *pieces,
325 struct piece_closure *c = XZALLOC (struct piece_closure);
330 c->n_pieces = n_pieces;
331 c->addr_size = addr_size;
332 c->pieces = XCALLOC (n_pieces, struct dwarf_expr_piece);
334 memcpy (c->pieces, pieces, n_pieces * sizeof (struct dwarf_expr_piece));
335 for (i = 0; i < n_pieces; ++i)
336 if (c->pieces[i].location == DWARF_VALUE_STACK)
337 value_incref (c->pieces[i].v.value);
342 /* The lowest-level function to extract bits from a byte buffer.
343 SOURCE is the buffer. It is updated if we read to the end of a
345 SOURCE_OFFSET_BITS is the offset of the first bit to read. It is
346 updated to reflect the number of bits actually read.
347 NBITS is the number of bits we want to read. It is updated to
348 reflect the number of bits actually read. This function may read
350 BITS_BIG_ENDIAN is taken directly from gdbarch.
351 This function returns the extracted bits. */
354 extract_bits_primitive (const gdb_byte **source,
355 unsigned int *source_offset_bits,
356 int *nbits, int bits_big_endian)
358 unsigned int avail, mask, datum;
360 gdb_assert (*source_offset_bits < 8);
362 avail = 8 - *source_offset_bits;
366 mask = (1 << avail) - 1;
369 datum >>= 8 - (*source_offset_bits + *nbits);
371 datum >>= *source_offset_bits;
375 *source_offset_bits += avail;
376 if (*source_offset_bits >= 8)
378 *source_offset_bits -= 8;
385 /* Extract some bits from a source buffer and move forward in the
388 SOURCE is the source buffer. It is updated as bytes are read.
389 SOURCE_OFFSET_BITS is the offset into SOURCE. It is updated as
391 NBITS is the number of bits to read.
392 BITS_BIG_ENDIAN is taken directly from gdbarch.
394 This function returns the bits that were read. */
397 extract_bits (const gdb_byte **source, unsigned int *source_offset_bits,
398 int nbits, int bits_big_endian)
402 gdb_assert (nbits > 0 && nbits <= 8);
404 datum = extract_bits_primitive (source, source_offset_bits, &nbits,
410 more = extract_bits_primitive (source, source_offset_bits, &nbits,
422 /* Write some bits into a buffer and move forward in the buffer.
424 DATUM is the bits to write. The low-order bits of DATUM are used.
425 DEST is the destination buffer. It is updated as bytes are
427 DEST_OFFSET_BITS is the bit offset in DEST at which writing is
429 NBITS is the number of valid bits in DATUM.
430 BITS_BIG_ENDIAN is taken directly from gdbarch. */
433 insert_bits (unsigned int datum,
434 gdb_byte *dest, unsigned int dest_offset_bits,
435 int nbits, int bits_big_endian)
439 gdb_assert (dest_offset_bits + nbits <= 8);
441 mask = (1 << nbits) - 1;
444 datum <<= 8 - (dest_offset_bits + nbits);
445 mask <<= 8 - (dest_offset_bits + nbits);
449 datum <<= dest_offset_bits;
450 mask <<= dest_offset_bits;
453 gdb_assert ((datum & ~mask) == 0);
455 *dest = (*dest & ~mask) | datum;
458 /* Copy bits from a source to a destination.
460 DEST is where the bits should be written.
461 DEST_OFFSET_BITS is the bit offset into DEST.
462 SOURCE is the source of bits.
463 SOURCE_OFFSET_BITS is the bit offset into SOURCE.
464 BIT_COUNT is the number of bits to copy.
465 BITS_BIG_ENDIAN is taken directly from gdbarch. */
468 copy_bitwise (gdb_byte *dest, unsigned int dest_offset_bits,
469 const gdb_byte *source, unsigned int source_offset_bits,
470 unsigned int bit_count,
473 unsigned int dest_avail;
476 /* Reduce everything to byte-size pieces. */
477 dest += dest_offset_bits / 8;
478 dest_offset_bits %= 8;
479 source += source_offset_bits / 8;
480 source_offset_bits %= 8;
482 dest_avail = 8 - dest_offset_bits % 8;
484 /* See if we can fill the first destination byte. */
485 if (dest_avail < bit_count)
487 datum = extract_bits (&source, &source_offset_bits, dest_avail,
489 insert_bits (datum, dest, dest_offset_bits, dest_avail, bits_big_endian);
491 dest_offset_bits = 0;
492 bit_count -= dest_avail;
495 /* Now, either DEST_OFFSET_BITS is byte-aligned, or we have fewer
496 than 8 bits remaining. */
497 gdb_assert (dest_offset_bits % 8 == 0 || bit_count < 8);
498 for (; bit_count >= 8; bit_count -= 8)
500 datum = extract_bits (&source, &source_offset_bits, 8, bits_big_endian);
501 *dest++ = (gdb_byte) datum;
504 /* Finally, we may have a few leftover bits. */
505 gdb_assert (bit_count <= 8 - dest_offset_bits % 8);
508 datum = extract_bits (&source, &source_offset_bits, bit_count,
510 insert_bits (datum, dest, dest_offset_bits, bit_count, bits_big_endian);
515 read_pieced_value (struct value *v)
519 ULONGEST bits_to_skip;
521 struct piece_closure *c
522 = (struct piece_closure *) value_computed_closure (v);
523 struct frame_info *frame = frame_find_by_id (VALUE_FRAME_ID (v));
525 size_t buffer_size = 0;
527 struct cleanup *cleanup;
529 = gdbarch_bits_big_endian (get_type_arch (value_type (v)));
531 if (value_type (v) != value_enclosing_type (v))
532 internal_error (__FILE__, __LINE__,
533 _("Should not be able to create a lazy value with "
534 "an enclosing type"));
536 cleanup = make_cleanup (free_current_contents, &buffer);
538 contents = value_contents_raw (v);
539 bits_to_skip = 8 * value_offset (v);
540 if (value_bitsize (v))
542 bits_to_skip += value_bitpos (v);
543 type_len = value_bitsize (v);
546 type_len = 8 * TYPE_LENGTH (value_type (v));
548 for (i = 0; i < c->n_pieces && offset < type_len; i++)
550 struct dwarf_expr_piece *p = &c->pieces[i];
551 size_t this_size, this_size_bits;
552 long dest_offset_bits, source_offset_bits, source_offset;
553 const gdb_byte *intermediate_buffer;
555 /* Compute size, source, and destination offsets for copying, in
557 this_size_bits = p->size;
558 if (bits_to_skip > 0 && bits_to_skip >= this_size_bits)
560 bits_to_skip -= this_size_bits;
563 if (this_size_bits > type_len - offset)
564 this_size_bits = type_len - offset;
565 if (bits_to_skip > 0)
567 dest_offset_bits = 0;
568 source_offset_bits = bits_to_skip;
569 this_size_bits -= bits_to_skip;
574 dest_offset_bits = offset;
575 source_offset_bits = 0;
578 this_size = (this_size_bits + source_offset_bits % 8 + 7) / 8;
579 source_offset = source_offset_bits / 8;
580 if (buffer_size < this_size)
582 buffer_size = this_size;
583 buffer = xrealloc (buffer, buffer_size);
585 intermediate_buffer = buffer;
587 /* Copy from the source to DEST_BUFFER. */
590 case DWARF_VALUE_REGISTER:
592 struct gdbarch *arch = get_frame_arch (frame);
593 int gdb_regnum = gdbarch_dwarf2_reg_to_regnum (arch, p->v.regno);
594 int reg_offset = source_offset;
596 if (gdbarch_byte_order (arch) == BFD_ENDIAN_BIG
597 && this_size < register_size (arch, gdb_regnum))
599 /* Big-endian, and we want less than full size. */
600 reg_offset = register_size (arch, gdb_regnum) - this_size;
601 /* We want the lower-order THIS_SIZE_BITS of the bytes
602 we extract from the register. */
603 source_offset_bits += 8 * this_size - this_size_bits;
606 if (gdb_regnum != -1)
610 if (!get_frame_register_bytes (frame, gdb_regnum, reg_offset,
614 /* Just so garbage doesn't ever shine through. */
615 memset (buffer, 0, this_size);
618 set_value_optimized_out (v, 1);
620 mark_value_bytes_unavailable (v, offset, this_size);
625 error (_("Unable to access DWARF register number %s"),
626 paddress (arch, p->v.regno));
631 case DWARF_VALUE_MEMORY:
632 read_value_memory (v, offset,
633 p->v.mem.in_stack_memory,
634 p->v.mem.addr + source_offset,
638 case DWARF_VALUE_STACK:
640 size_t n = this_size;
642 if (n > c->addr_size - source_offset)
643 n = (c->addr_size >= source_offset
644 ? c->addr_size - source_offset
652 const gdb_byte *val_bytes = value_contents_all (p->v.value);
654 intermediate_buffer = val_bytes + source_offset;
659 case DWARF_VALUE_LITERAL:
661 size_t n = this_size;
663 if (n > p->v.literal.length - source_offset)
664 n = (p->v.literal.length >= source_offset
665 ? p->v.literal.length - source_offset
668 intermediate_buffer = p->v.literal.data + source_offset;
672 /* These bits show up as zeros -- but do not cause the value
673 to be considered optimized-out. */
674 case DWARF_VALUE_IMPLICIT_POINTER:
677 case DWARF_VALUE_OPTIMIZED_OUT:
678 set_value_optimized_out (v, 1);
682 internal_error (__FILE__, __LINE__, _("invalid location type"));
685 if (p->location != DWARF_VALUE_OPTIMIZED_OUT
686 && p->location != DWARF_VALUE_IMPLICIT_POINTER)
687 copy_bitwise (contents, dest_offset_bits,
688 intermediate_buffer, source_offset_bits % 8,
689 this_size_bits, bits_big_endian);
691 offset += this_size_bits;
694 do_cleanups (cleanup);
698 write_pieced_value (struct value *to, struct value *from)
702 ULONGEST bits_to_skip;
703 const gdb_byte *contents;
704 struct piece_closure *c
705 = (struct piece_closure *) value_computed_closure (to);
706 struct frame_info *frame = frame_find_by_id (VALUE_FRAME_ID (to));
708 size_t buffer_size = 0;
710 struct cleanup *cleanup;
712 = gdbarch_bits_big_endian (get_type_arch (value_type (to)));
716 set_value_optimized_out (to, 1);
720 cleanup = make_cleanup (free_current_contents, &buffer);
722 contents = value_contents (from);
723 bits_to_skip = 8 * value_offset (to);
724 if (value_bitsize (to))
726 bits_to_skip += value_bitpos (to);
727 type_len = value_bitsize (to);
730 type_len = 8 * TYPE_LENGTH (value_type (to));
732 for (i = 0; i < c->n_pieces && offset < type_len; i++)
734 struct dwarf_expr_piece *p = &c->pieces[i];
735 size_t this_size_bits, this_size;
736 long dest_offset_bits, source_offset_bits, dest_offset, source_offset;
738 const gdb_byte *source_buffer;
740 this_size_bits = p->size;
741 if (bits_to_skip > 0 && bits_to_skip >= this_size_bits)
743 bits_to_skip -= this_size_bits;
746 if (this_size_bits > type_len - offset)
747 this_size_bits = type_len - offset;
748 if (bits_to_skip > 0)
750 dest_offset_bits = bits_to_skip;
751 source_offset_bits = 0;
752 this_size_bits -= bits_to_skip;
757 dest_offset_bits = 0;
758 source_offset_bits = offset;
761 this_size = (this_size_bits + source_offset_bits % 8 + 7) / 8;
762 source_offset = source_offset_bits / 8;
763 dest_offset = dest_offset_bits / 8;
764 if (dest_offset_bits % 8 == 0 && source_offset_bits % 8 == 0)
766 source_buffer = contents + source_offset;
771 if (buffer_size < this_size)
773 buffer_size = this_size;
774 buffer = xrealloc (buffer, buffer_size);
776 source_buffer = buffer;
782 case DWARF_VALUE_REGISTER:
784 struct gdbarch *arch = get_frame_arch (frame);
785 int gdb_regnum = gdbarch_dwarf2_reg_to_regnum (arch, p->v.regno);
786 int reg_offset = dest_offset;
788 if (gdbarch_byte_order (arch) == BFD_ENDIAN_BIG
789 && this_size <= register_size (arch, gdb_regnum))
790 /* Big-endian, and we want less than full size. */
791 reg_offset = register_size (arch, gdb_regnum) - this_size;
793 if (gdb_regnum != -1)
799 if (!get_frame_register_bytes (frame, gdb_regnum, reg_offset,
804 error (_("Can't do read-modify-write to "
805 "update bitfield; containing word has been "
808 throw_error (NOT_AVAILABLE_ERROR,
809 _("Can't do read-modify-write to update "
810 "bitfield; containing word "
813 copy_bitwise (buffer, dest_offset_bits,
814 contents, source_offset_bits,
819 put_frame_register_bytes (frame, gdb_regnum, reg_offset,
820 this_size, source_buffer);
824 error (_("Unable to write to DWARF register number %s"),
825 paddress (arch, p->v.regno));
829 case DWARF_VALUE_MEMORY:
832 /* Only the first and last bytes can possibly have any
834 read_memory (p->v.mem.addr + dest_offset, buffer, 1);
835 read_memory (p->v.mem.addr + dest_offset + this_size - 1,
836 buffer + this_size - 1, 1);
837 copy_bitwise (buffer, dest_offset_bits,
838 contents, source_offset_bits,
843 write_memory (p->v.mem.addr + dest_offset,
844 source_buffer, this_size);
847 set_value_optimized_out (to, 1);
850 offset += this_size_bits;
853 do_cleanups (cleanup);
856 /* A helper function that checks bit validity in a pieced value.
857 CHECK_FOR indicates the kind of validity checking.
858 DWARF_VALUE_MEMORY means to check whether any bit is valid.
859 DWARF_VALUE_OPTIMIZED_OUT means to check whether any bit is
861 DWARF_VALUE_IMPLICIT_POINTER means to check whether the bits are an
865 check_pieced_value_bits (const struct value *value, int bit_offset,
867 enum dwarf_value_location check_for)
869 struct piece_closure *c
870 = (struct piece_closure *) value_computed_closure (value);
872 int validity = (check_for == DWARF_VALUE_MEMORY
873 || check_for == DWARF_VALUE_IMPLICIT_POINTER);
875 bit_offset += 8 * value_offset (value);
876 if (value_bitsize (value))
877 bit_offset += value_bitpos (value);
879 for (i = 0; i < c->n_pieces && bit_length > 0; i++)
881 struct dwarf_expr_piece *p = &c->pieces[i];
882 size_t this_size_bits = p->size;
886 if (bit_offset >= this_size_bits)
888 bit_offset -= this_size_bits;
892 bit_length -= this_size_bits - bit_offset;
896 bit_length -= this_size_bits;
898 if (check_for == DWARF_VALUE_IMPLICIT_POINTER)
900 if (p->location != DWARF_VALUE_IMPLICIT_POINTER)
903 else if (p->location == DWARF_VALUE_OPTIMIZED_OUT
904 || p->location == DWARF_VALUE_IMPLICIT_POINTER)
920 check_pieced_value_validity (const struct value *value, int bit_offset,
923 return check_pieced_value_bits (value, bit_offset, bit_length,
928 check_pieced_value_invalid (const struct value *value)
930 return check_pieced_value_bits (value, 0,
931 8 * TYPE_LENGTH (value_type (value)),
932 DWARF_VALUE_OPTIMIZED_OUT);
935 /* An implementation of an lval_funcs method to see whether a value is
936 a synthetic pointer. */
939 check_pieced_synthetic_pointer (const struct value *value, int bit_offset,
942 return check_pieced_value_bits (value, bit_offset, bit_length,
943 DWARF_VALUE_IMPLICIT_POINTER);
946 /* A wrapper function for get_frame_address_in_block. */
949 get_frame_address_in_block_wrapper (void *baton)
951 return get_frame_address_in_block (baton);
954 /* An implementation of an lval_funcs method to indirect through a
955 pointer. This handles the synthetic pointer case when needed. */
957 static struct value *
958 indirect_pieced_value (struct value *value)
960 struct piece_closure *c
961 = (struct piece_closure *) value_computed_closure (value);
963 struct frame_info *frame;
964 struct dwarf2_locexpr_baton baton;
965 int i, bit_offset, bit_length;
966 struct dwarf_expr_piece *piece = NULL;
967 struct value *result;
970 type = value_type (value);
971 if (TYPE_CODE (type) != TYPE_CODE_PTR)
974 bit_length = 8 * TYPE_LENGTH (type);
975 bit_offset = 8 * value_offset (value);
976 if (value_bitsize (value))
977 bit_offset += value_bitpos (value);
979 for (i = 0; i < c->n_pieces && bit_length > 0; i++)
981 struct dwarf_expr_piece *p = &c->pieces[i];
982 size_t this_size_bits = p->size;
986 if (bit_offset >= this_size_bits)
988 bit_offset -= this_size_bits;
992 bit_length -= this_size_bits - bit_offset;
996 bit_length -= this_size_bits;
998 if (p->location != DWARF_VALUE_IMPLICIT_POINTER)
1001 if (bit_length != 0)
1002 error (_("Invalid use of DW_OP_GNU_implicit_pointer"));
1008 frame = get_selected_frame (_("No frame selected."));
1009 byte_offset = value_as_address (value);
1012 baton = dwarf2_fetch_die_location_block (piece->v.ptr.die, c->per_cu,
1013 get_frame_address_in_block_wrapper,
1016 result = dwarf2_evaluate_loc_desc_full (TYPE_TARGET_TYPE (type), frame,
1017 baton.data, baton.size, baton.per_cu,
1024 copy_pieced_value_closure (const struct value *v)
1026 struct piece_closure *c
1027 = (struct piece_closure *) value_computed_closure (v);
1034 free_pieced_value_closure (struct value *v)
1036 struct piece_closure *c
1037 = (struct piece_closure *) value_computed_closure (v);
1044 for (i = 0; i < c->n_pieces; ++i)
1045 if (c->pieces[i].location == DWARF_VALUE_STACK)
1046 value_free (c->pieces[i].v.value);
1053 /* Functions for accessing a variable described by DW_OP_piece. */
1054 static struct lval_funcs pieced_value_funcs = {
1057 check_pieced_value_validity,
1058 check_pieced_value_invalid,
1059 indirect_pieced_value,
1060 check_pieced_synthetic_pointer,
1061 copy_pieced_value_closure,
1062 free_pieced_value_closure
1065 /* Helper function which throws an error if a synthetic pointer is
1069 invalid_synthetic_pointer (void)
1071 error (_("access outside bounds of object "
1072 "referenced via synthetic pointer"));
1075 /* Evaluate a location description, starting at DATA and with length
1076 SIZE, to find the current location of variable of TYPE in the
1077 context of FRAME. BYTE_OFFSET is applied after the contents are
1080 static struct value *
1081 dwarf2_evaluate_loc_desc_full (struct type *type, struct frame_info *frame,
1082 const gdb_byte *data, unsigned short size,
1083 struct dwarf2_per_cu_data *per_cu,
1084 LONGEST byte_offset)
1086 struct value *retval;
1087 struct dwarf_expr_baton baton;
1088 struct dwarf_expr_context *ctx;
1089 struct cleanup *old_chain;
1090 struct objfile *objfile = dwarf2_per_cu_objfile (per_cu);
1091 volatile struct gdb_exception ex;
1093 if (byte_offset < 0)
1094 invalid_synthetic_pointer ();
1098 retval = allocate_value (type);
1099 VALUE_LVAL (retval) = not_lval;
1100 set_value_optimized_out (retval, 1);
1104 baton.frame = frame;
1105 baton.per_cu = per_cu;
1107 ctx = new_dwarf_expr_context ();
1108 old_chain = make_cleanup_free_dwarf_expr_context (ctx);
1110 ctx->gdbarch = get_objfile_arch (objfile);
1111 ctx->addr_size = dwarf2_per_cu_addr_size (per_cu);
1112 ctx->offset = dwarf2_per_cu_text_offset (per_cu);
1113 ctx->baton = &baton;
1114 ctx->read_reg = dwarf_expr_read_reg;
1115 ctx->read_mem = dwarf_expr_read_mem;
1116 ctx->get_frame_base = dwarf_expr_frame_base;
1117 ctx->get_frame_cfa = dwarf_expr_frame_cfa;
1118 ctx->get_frame_pc = dwarf_expr_frame_pc;
1119 ctx->get_tls_address = dwarf_expr_tls_address;
1120 ctx->dwarf_call = dwarf_expr_dwarf_call;
1121 ctx->get_base_type = dwarf_expr_get_base_type;
1123 TRY_CATCH (ex, RETURN_MASK_ERROR)
1125 dwarf_expr_eval (ctx, data, size);
1129 if (ex.error == NOT_AVAILABLE_ERROR)
1131 retval = allocate_value (type);
1132 mark_value_bytes_unavailable (retval, 0, TYPE_LENGTH (type));
1136 throw_exception (ex);
1139 if (ctx->num_pieces > 0)
1141 struct piece_closure *c;
1142 struct frame_id frame_id = get_frame_id (frame);
1143 ULONGEST bit_size = 0;
1146 for (i = 0; i < ctx->num_pieces; ++i)
1147 bit_size += ctx->pieces[i].size;
1148 if (8 * (byte_offset + TYPE_LENGTH (type)) > bit_size)
1149 invalid_synthetic_pointer ();
1151 c = allocate_piece_closure (per_cu, ctx->num_pieces, ctx->pieces,
1153 retval = allocate_computed_value (type, &pieced_value_funcs, c);
1154 VALUE_FRAME_ID (retval) = frame_id;
1155 set_value_offset (retval, byte_offset);
1159 switch (ctx->location)
1161 case DWARF_VALUE_REGISTER:
1163 struct gdbarch *arch = get_frame_arch (frame);
1164 ULONGEST dwarf_regnum = value_as_long (dwarf_expr_fetch (ctx, 0));
1165 int gdb_regnum = gdbarch_dwarf2_reg_to_regnum (arch, dwarf_regnum);
1167 if (byte_offset != 0)
1168 error (_("cannot use offset on synthetic pointer to register"));
1169 if (gdb_regnum != -1)
1170 retval = value_from_register (type, gdb_regnum, frame);
1172 error (_("Unable to access DWARF register number %s"),
1173 paddress (arch, dwarf_regnum));
1177 case DWARF_VALUE_MEMORY:
1179 CORE_ADDR address = dwarf_expr_fetch_address (ctx, 0);
1180 int in_stack_memory = dwarf_expr_fetch_in_stack_memory (ctx, 0);
1182 retval = allocate_value_lazy (type);
1183 VALUE_LVAL (retval) = lval_memory;
1184 if (in_stack_memory)
1185 set_value_stack (retval, 1);
1186 set_value_address (retval, address + byte_offset);
1190 case DWARF_VALUE_STACK:
1192 struct value *value = dwarf_expr_fetch (ctx, 0);
1194 const gdb_byte *val_bytes;
1195 size_t n = TYPE_LENGTH (value_type (value));
1197 if (byte_offset + TYPE_LENGTH (type) > n)
1198 invalid_synthetic_pointer ();
1200 val_bytes = value_contents_all (value);
1201 val_bytes += byte_offset;
1204 retval = allocate_value (type);
1205 contents = value_contents_raw (retval);
1206 if (n > TYPE_LENGTH (type))
1207 n = TYPE_LENGTH (type);
1208 memcpy (contents, val_bytes, n);
1212 case DWARF_VALUE_LITERAL:
1215 const bfd_byte *ldata;
1216 size_t n = ctx->len;
1218 if (byte_offset + TYPE_LENGTH (type) > n)
1219 invalid_synthetic_pointer ();
1221 retval = allocate_value (type);
1222 contents = value_contents_raw (retval);
1224 ldata = ctx->data + byte_offset;
1227 if (n > TYPE_LENGTH (type))
1228 n = TYPE_LENGTH (type);
1229 memcpy (contents, ldata, n);
1233 case DWARF_VALUE_OPTIMIZED_OUT:
1234 retval = allocate_value (type);
1235 VALUE_LVAL (retval) = not_lval;
1236 set_value_optimized_out (retval, 1);
1239 /* DWARF_VALUE_IMPLICIT_POINTER was converted to a pieced
1240 operation by execute_stack_op. */
1241 case DWARF_VALUE_IMPLICIT_POINTER:
1242 /* DWARF_VALUE_OPTIMIZED_OUT can't occur in this context --
1243 it can only be encountered when making a piece. */
1245 internal_error (__FILE__, __LINE__, _("invalid location type"));
1249 set_value_initialized (retval, ctx->initialized);
1251 do_cleanups (old_chain);
1256 /* The exported interface to dwarf2_evaluate_loc_desc_full; it always
1257 passes 0 as the byte_offset. */
1260 dwarf2_evaluate_loc_desc (struct type *type, struct frame_info *frame,
1261 const gdb_byte *data, unsigned short size,
1262 struct dwarf2_per_cu_data *per_cu)
1264 return dwarf2_evaluate_loc_desc_full (type, frame, data, size, per_cu, 0);
1268 /* Helper functions and baton for dwarf2_loc_desc_needs_frame. */
1270 struct needs_frame_baton
1273 struct dwarf2_per_cu_data *per_cu;
1276 /* Reads from registers do require a frame. */
1278 needs_frame_read_reg (void *baton, int regnum)
1280 struct needs_frame_baton *nf_baton = baton;
1282 nf_baton->needs_frame = 1;
1286 /* Reads from memory do not require a frame. */
1288 needs_frame_read_mem (void *baton, gdb_byte *buf, CORE_ADDR addr, size_t len)
1290 memset (buf, 0, len);
1293 /* Frame-relative accesses do require a frame. */
1295 needs_frame_frame_base (void *baton, const gdb_byte **start, size_t * length)
1297 static gdb_byte lit0 = DW_OP_lit0;
1298 struct needs_frame_baton *nf_baton = baton;
1303 nf_baton->needs_frame = 1;
1306 /* CFA accesses require a frame. */
1309 needs_frame_frame_cfa (void *baton)
1311 struct needs_frame_baton *nf_baton = baton;
1313 nf_baton->needs_frame = 1;
1317 /* Thread-local accesses do require a frame. */
1319 needs_frame_tls_address (void *baton, CORE_ADDR offset)
1321 struct needs_frame_baton *nf_baton = baton;
1323 nf_baton->needs_frame = 1;
1327 /* Helper interface of per_cu_dwarf_call for dwarf2_loc_desc_needs_frame. */
1330 needs_frame_dwarf_call (struct dwarf_expr_context *ctx, size_t die_offset)
1332 struct needs_frame_baton *nf_baton = ctx->baton;
1334 per_cu_dwarf_call (ctx, die_offset, nf_baton->per_cu,
1335 ctx->get_frame_pc, ctx->baton);
1338 /* Return non-zero iff the location expression at DATA (length SIZE)
1339 requires a frame to evaluate. */
1342 dwarf2_loc_desc_needs_frame (const gdb_byte *data, unsigned short size,
1343 struct dwarf2_per_cu_data *per_cu)
1345 struct needs_frame_baton baton;
1346 struct dwarf_expr_context *ctx;
1348 struct cleanup *old_chain;
1349 struct objfile *objfile = dwarf2_per_cu_objfile (per_cu);
1351 baton.needs_frame = 0;
1352 baton.per_cu = per_cu;
1354 ctx = new_dwarf_expr_context ();
1355 old_chain = make_cleanup_free_dwarf_expr_context (ctx);
1357 ctx->gdbarch = get_objfile_arch (objfile);
1358 ctx->addr_size = dwarf2_per_cu_addr_size (per_cu);
1359 ctx->offset = dwarf2_per_cu_text_offset (per_cu);
1360 ctx->baton = &baton;
1361 ctx->read_reg = needs_frame_read_reg;
1362 ctx->read_mem = needs_frame_read_mem;
1363 ctx->get_frame_base = needs_frame_frame_base;
1364 ctx->get_frame_cfa = needs_frame_frame_cfa;
1365 ctx->get_frame_pc = needs_frame_frame_cfa;
1366 ctx->get_tls_address = needs_frame_tls_address;
1367 ctx->dwarf_call = needs_frame_dwarf_call;
1369 dwarf_expr_eval (ctx, data, size);
1371 in_reg = ctx->location == DWARF_VALUE_REGISTER;
1373 if (ctx->num_pieces > 0)
1377 /* If the location has several pieces, and any of them are in
1378 registers, then we will need a frame to fetch them from. */
1379 for (i = 0; i < ctx->num_pieces; i++)
1380 if (ctx->pieces[i].location == DWARF_VALUE_REGISTER)
1384 do_cleanups (old_chain);
1386 return baton.needs_frame || in_reg;
1389 /* A helper function that throws an unimplemented error mentioning a
1390 given DWARF operator. */
1393 unimplemented (unsigned int op)
1395 const char *name = dwarf_stack_op_name (op);
1398 error (_("DWARF operator %s cannot be translated to an agent expression"),
1401 error (_("Unknown DWARF operator 0x%02x cannot be translated "
1402 "to an agent expression"),
1406 /* A helper function to convert a DWARF register to an arch register.
1407 ARCH is the architecture.
1408 DWARF_REG is the register.
1409 This will throw an exception if the DWARF register cannot be
1410 translated to an architecture register. */
1413 translate_register (struct gdbarch *arch, int dwarf_reg)
1415 int reg = gdbarch_dwarf2_reg_to_regnum (arch, dwarf_reg);
1417 error (_("Unable to access DWARF register number %d"), dwarf_reg);
1421 /* A helper function that emits an access to memory. ARCH is the
1422 target architecture. EXPR is the expression which we are building.
1423 NBITS is the number of bits we want to read. This emits the
1424 opcodes needed to read the memory and then extract the desired
1428 access_memory (struct gdbarch *arch, struct agent_expr *expr, ULONGEST nbits)
1430 ULONGEST nbytes = (nbits + 7) / 8;
1432 gdb_assert (nbits > 0 && nbits <= sizeof (LONGEST));
1435 ax_trace_quick (expr, nbytes);
1438 ax_simple (expr, aop_ref8);
1439 else if (nbits <= 16)
1440 ax_simple (expr, aop_ref16);
1441 else if (nbits <= 32)
1442 ax_simple (expr, aop_ref32);
1444 ax_simple (expr, aop_ref64);
1446 /* If we read exactly the number of bytes we wanted, we're done. */
1447 if (8 * nbytes == nbits)
1450 if (gdbarch_bits_big_endian (arch))
1452 /* On a bits-big-endian machine, we want the high-order
1454 ax_const_l (expr, 8 * nbytes - nbits);
1455 ax_simple (expr, aop_rsh_unsigned);
1459 /* On a bits-little-endian box, we want the low-order NBITS. */
1460 ax_zero_ext (expr, nbits);
1464 /* A helper function to return the frame's PC. */
1467 get_ax_pc (void *baton)
1469 struct agent_expr *expr = baton;
1474 /* Compile a DWARF location expression to an agent expression.
1476 EXPR is the agent expression we are building.
1477 LOC is the agent value we modify.
1478 ARCH is the architecture.
1479 ADDR_SIZE is the size of addresses, in bytes.
1480 OP_PTR is the start of the location expression.
1481 OP_END is one past the last byte of the location expression.
1483 This will throw an exception for various kinds of errors -- for
1484 example, if the expression cannot be compiled, or if the expression
1488 dwarf2_compile_expr_to_ax (struct agent_expr *expr, struct axs_value *loc,
1489 struct gdbarch *arch, unsigned int addr_size,
1490 const gdb_byte *op_ptr, const gdb_byte *op_end,
1491 struct dwarf2_per_cu_data *per_cu)
1493 struct cleanup *cleanups;
1495 VEC(int) *dw_labels = NULL, *patches = NULL;
1496 const gdb_byte * const base = op_ptr;
1497 const gdb_byte *previous_piece = op_ptr;
1498 enum bfd_endian byte_order = gdbarch_byte_order (arch);
1499 ULONGEST bits_collected = 0;
1500 unsigned int addr_size_bits = 8 * addr_size;
1501 int bits_big_endian = gdbarch_bits_big_endian (arch);
1503 offsets = xmalloc ((op_end - op_ptr) * sizeof (int));
1504 cleanups = make_cleanup (xfree, offsets);
1506 for (i = 0; i < op_end - op_ptr; ++i)
1509 make_cleanup (VEC_cleanup (int), &dw_labels);
1510 make_cleanup (VEC_cleanup (int), &patches);
1512 /* By default we are making an address. */
1513 loc->kind = axs_lvalue_memory;
1515 while (op_ptr < op_end)
1517 enum dwarf_location_atom op = *op_ptr;
1518 ULONGEST uoffset, reg;
1522 offsets[op_ptr - base] = expr->len;
1525 /* Our basic approach to code generation is to map DWARF
1526 operations directly to AX operations. However, there are
1529 First, DWARF works on address-sized units, but AX always uses
1530 LONGEST. For most operations we simply ignore this
1531 difference; instead we generate sign extensions as needed
1532 before division and comparison operations. It would be nice
1533 to omit the sign extensions, but there is no way to determine
1534 the size of the target's LONGEST. (This code uses the size
1535 of the host LONGEST in some cases -- that is a bug but it is
1538 Second, some DWARF operations cannot be translated to AX.
1539 For these we simply fail. See
1540 http://sourceware.org/bugzilla/show_bug.cgi?id=11662. */
1575 ax_const_l (expr, op - DW_OP_lit0);
1579 uoffset = extract_unsigned_integer (op_ptr, addr_size, byte_order);
1580 op_ptr += addr_size;
1581 /* Some versions of GCC emit DW_OP_addr before
1582 DW_OP_GNU_push_tls_address. In this case the value is an
1583 index, not an address. We don't support things like
1584 branching between the address and the TLS op. */
1585 if (op_ptr >= op_end || *op_ptr != DW_OP_GNU_push_tls_address)
1586 uoffset += dwarf2_per_cu_text_offset (per_cu);
1587 ax_const_l (expr, uoffset);
1591 ax_const_l (expr, extract_unsigned_integer (op_ptr, 1, byte_order));
1595 ax_const_l (expr, extract_signed_integer (op_ptr, 1, byte_order));
1599 ax_const_l (expr, extract_unsigned_integer (op_ptr, 2, byte_order));
1603 ax_const_l (expr, extract_signed_integer (op_ptr, 2, byte_order));
1607 ax_const_l (expr, extract_unsigned_integer (op_ptr, 4, byte_order));
1611 ax_const_l (expr, extract_signed_integer (op_ptr, 4, byte_order));
1615 ax_const_l (expr, extract_unsigned_integer (op_ptr, 8, byte_order));
1619 ax_const_l (expr, extract_signed_integer (op_ptr, 8, byte_order));
1623 op_ptr = read_uleb128 (op_ptr, op_end, &uoffset);
1624 ax_const_l (expr, uoffset);
1627 op_ptr = read_sleb128 (op_ptr, op_end, &offset);
1628 ax_const_l (expr, offset);
1663 dwarf_expr_require_composition (op_ptr, op_end, "DW_OP_regx");
1664 loc->u.reg = translate_register (arch, op - DW_OP_reg0);
1665 loc->kind = axs_lvalue_register;
1669 op_ptr = read_uleb128 (op_ptr, op_end, ®);
1670 dwarf_expr_require_composition (op_ptr, op_end, "DW_OP_regx");
1671 loc->u.reg = translate_register (arch, reg);
1672 loc->kind = axs_lvalue_register;
1675 case DW_OP_implicit_value:
1679 op_ptr = read_uleb128 (op_ptr, op_end, &len);
1680 if (op_ptr + len > op_end)
1681 error (_("DW_OP_implicit_value: too few bytes available."));
1682 if (len > sizeof (ULONGEST))
1683 error (_("Cannot translate DW_OP_implicit_value of %d bytes"),
1686 ax_const_l (expr, extract_unsigned_integer (op_ptr, len,
1689 dwarf_expr_require_composition (op_ptr, op_end,
1690 "DW_OP_implicit_value");
1692 loc->kind = axs_rvalue;
1696 case DW_OP_stack_value:
1697 dwarf_expr_require_composition (op_ptr, op_end, "DW_OP_stack_value");
1698 loc->kind = axs_rvalue;
1733 op_ptr = read_sleb128 (op_ptr, op_end, &offset);
1734 i = translate_register (arch, op - DW_OP_breg0);
1738 ax_const_l (expr, offset);
1739 ax_simple (expr, aop_add);
1744 op_ptr = read_uleb128 (op_ptr, op_end, ®);
1745 op_ptr = read_sleb128 (op_ptr, op_end, &offset);
1746 i = translate_register (arch, reg);
1750 ax_const_l (expr, offset);
1751 ax_simple (expr, aop_add);
1757 const gdb_byte *datastart;
1759 unsigned int before_stack_len;
1761 struct symbol *framefunc;
1762 LONGEST base_offset = 0;
1764 b = block_for_pc (expr->scope);
1767 error (_("No block found for address"));
1769 framefunc = block_linkage_function (b);
1772 error (_("No function found for block"));
1774 dwarf_expr_frame_base_1 (framefunc, expr->scope,
1775 &datastart, &datalen);
1777 op_ptr = read_sleb128 (op_ptr, op_end, &offset);
1778 dwarf2_compile_expr_to_ax (expr, loc, arch, addr_size, datastart,
1779 datastart + datalen, per_cu);
1783 ax_const_l (expr, offset);
1784 ax_simple (expr, aop_add);
1787 loc->kind = axs_lvalue_memory;
1792 ax_simple (expr, aop_dup);
1796 ax_simple (expr, aop_pop);
1801 ax_pick (expr, offset);
1805 ax_simple (expr, aop_swap);
1813 ax_simple (expr, aop_rot);
1817 case DW_OP_deref_size:
1821 if (op == DW_OP_deref_size)
1829 ax_simple (expr, aop_ref8);
1832 ax_simple (expr, aop_ref16);
1835 ax_simple (expr, aop_ref32);
1838 ax_simple (expr, aop_ref64);
1841 /* Note that dwarf_stack_op_name will never return
1843 error (_("Unsupported size %d in %s"),
1844 size, dwarf_stack_op_name (op));
1850 /* Sign extend the operand. */
1851 ax_ext (expr, addr_size_bits);
1852 ax_simple (expr, aop_dup);
1853 ax_const_l (expr, 0);
1854 ax_simple (expr, aop_less_signed);
1855 ax_simple (expr, aop_log_not);
1856 i = ax_goto (expr, aop_if_goto);
1857 /* We have to emit 0 - X. */
1858 ax_const_l (expr, 0);
1859 ax_simple (expr, aop_swap);
1860 ax_simple (expr, aop_sub);
1861 ax_label (expr, i, expr->len);
1865 /* No need to sign extend here. */
1866 ax_const_l (expr, 0);
1867 ax_simple (expr, aop_swap);
1868 ax_simple (expr, aop_sub);
1872 /* Sign extend the operand. */
1873 ax_ext (expr, addr_size_bits);
1874 ax_simple (expr, aop_bit_not);
1877 case DW_OP_plus_uconst:
1878 op_ptr = read_uleb128 (op_ptr, op_end, ®);
1879 /* It would be really weird to emit `DW_OP_plus_uconst 0',
1880 but we micro-optimize anyhow. */
1883 ax_const_l (expr, reg);
1884 ax_simple (expr, aop_add);
1889 ax_simple (expr, aop_bit_and);
1893 /* Sign extend the operands. */
1894 ax_ext (expr, addr_size_bits);
1895 ax_simple (expr, aop_swap);
1896 ax_ext (expr, addr_size_bits);
1897 ax_simple (expr, aop_swap);
1898 ax_simple (expr, aop_div_signed);
1902 ax_simple (expr, aop_sub);
1906 ax_simple (expr, aop_rem_unsigned);
1910 ax_simple (expr, aop_mul);
1914 ax_simple (expr, aop_bit_or);
1918 ax_simple (expr, aop_add);
1922 ax_simple (expr, aop_lsh);
1926 ax_simple (expr, aop_rsh_unsigned);
1930 ax_simple (expr, aop_rsh_signed);
1934 ax_simple (expr, aop_bit_xor);
1938 /* Sign extend the operands. */
1939 ax_ext (expr, addr_size_bits);
1940 ax_simple (expr, aop_swap);
1941 ax_ext (expr, addr_size_bits);
1942 /* Note no swap here: A <= B is !(B < A). */
1943 ax_simple (expr, aop_less_signed);
1944 ax_simple (expr, aop_log_not);
1948 /* Sign extend the operands. */
1949 ax_ext (expr, addr_size_bits);
1950 ax_simple (expr, aop_swap);
1951 ax_ext (expr, addr_size_bits);
1952 ax_simple (expr, aop_swap);
1953 /* A >= B is !(A < B). */
1954 ax_simple (expr, aop_less_signed);
1955 ax_simple (expr, aop_log_not);
1959 /* Sign extend the operands. */
1960 ax_ext (expr, addr_size_bits);
1961 ax_simple (expr, aop_swap);
1962 ax_ext (expr, addr_size_bits);
1963 /* No need for a second swap here. */
1964 ax_simple (expr, aop_equal);
1968 /* Sign extend the operands. */
1969 ax_ext (expr, addr_size_bits);
1970 ax_simple (expr, aop_swap);
1971 ax_ext (expr, addr_size_bits);
1972 ax_simple (expr, aop_swap);
1973 ax_simple (expr, aop_less_signed);
1977 /* Sign extend the operands. */
1978 ax_ext (expr, addr_size_bits);
1979 ax_simple (expr, aop_swap);
1980 ax_ext (expr, addr_size_bits);
1981 /* Note no swap here: A > B is B < A. */
1982 ax_simple (expr, aop_less_signed);
1986 /* Sign extend the operands. */
1987 ax_ext (expr, addr_size_bits);
1988 ax_simple (expr, aop_swap);
1989 ax_ext (expr, addr_size_bits);
1990 /* No need for a swap here. */
1991 ax_simple (expr, aop_equal);
1992 ax_simple (expr, aop_log_not);
1995 case DW_OP_call_frame_cfa:
1996 dwarf2_compile_cfa_to_ax (expr, loc, arch, expr->scope, per_cu);
1997 loc->kind = axs_lvalue_memory;
2000 case DW_OP_GNU_push_tls_address:
2005 offset = extract_signed_integer (op_ptr, 2, byte_order);
2007 i = ax_goto (expr, aop_goto);
2008 VEC_safe_push (int, dw_labels, op_ptr + offset - base);
2009 VEC_safe_push (int, patches, i);
2013 offset = extract_signed_integer (op_ptr, 2, byte_order);
2015 /* Zero extend the operand. */
2016 ax_zero_ext (expr, addr_size_bits);
2017 i = ax_goto (expr, aop_if_goto);
2018 VEC_safe_push (int, dw_labels, op_ptr + offset - base);
2019 VEC_safe_push (int, patches, i);
2026 case DW_OP_bit_piece:
2028 ULONGEST size, offset;
2030 if (op_ptr - 1 == previous_piece)
2031 error (_("Cannot translate empty pieces to agent expressions"));
2032 previous_piece = op_ptr - 1;
2034 op_ptr = read_uleb128 (op_ptr, op_end, &size);
2035 if (op == DW_OP_piece)
2041 op_ptr = read_uleb128 (op_ptr, op_end, &offset);
2043 if (bits_collected + size > 8 * sizeof (LONGEST))
2044 error (_("Expression pieces exceed word size"));
2046 /* Access the bits. */
2049 case axs_lvalue_register:
2050 ax_reg (expr, loc->u.reg);
2053 case axs_lvalue_memory:
2054 /* Offset the pointer, if needed. */
2057 ax_const_l (expr, offset / 8);
2058 ax_simple (expr, aop_add);
2061 access_memory (arch, expr, size);
2065 /* For a bits-big-endian target, shift up what we already
2066 have. For a bits-little-endian target, shift up the
2067 new data. Note that there is a potential bug here if
2068 the DWARF expression leaves multiple values on the
2070 if (bits_collected > 0)
2072 if (bits_big_endian)
2074 ax_simple (expr, aop_swap);
2075 ax_const_l (expr, size);
2076 ax_simple (expr, aop_lsh);
2077 /* We don't need a second swap here, because
2078 aop_bit_or is symmetric. */
2082 ax_const_l (expr, size);
2083 ax_simple (expr, aop_lsh);
2085 ax_simple (expr, aop_bit_or);
2088 bits_collected += size;
2089 loc->kind = axs_rvalue;
2093 case DW_OP_GNU_uninit:
2099 struct dwarf2_locexpr_baton block;
2100 int size = (op == DW_OP_call2 ? 2 : 4);
2102 uoffset = extract_unsigned_integer (op_ptr, size, byte_order);
2105 block = dwarf2_fetch_die_location_block (uoffset, per_cu,
2108 /* DW_OP_call_ref is currently not supported. */
2109 gdb_assert (block.per_cu == per_cu);
2111 dwarf2_compile_expr_to_ax (expr, loc, arch, addr_size,
2112 block.data, block.data + block.size,
2117 case DW_OP_call_ref:
2125 /* Patch all the branches we emitted. */
2126 for (i = 0; i < VEC_length (int, patches); ++i)
2128 int targ = offsets[VEC_index (int, dw_labels, i)];
2130 internal_error (__FILE__, __LINE__, _("invalid label"));
2131 ax_label (expr, VEC_index (int, patches, i), targ);
2134 do_cleanups (cleanups);
2138 /* Return the value of SYMBOL in FRAME using the DWARF-2 expression
2139 evaluator to calculate the location. */
2140 static struct value *
2141 locexpr_read_variable (struct symbol *symbol, struct frame_info *frame)
2143 struct dwarf2_locexpr_baton *dlbaton = SYMBOL_LOCATION_BATON (symbol);
2146 val = dwarf2_evaluate_loc_desc (SYMBOL_TYPE (symbol), frame, dlbaton->data,
2147 dlbaton->size, dlbaton->per_cu);
2152 /* Return non-zero iff we need a frame to evaluate SYMBOL. */
2154 locexpr_read_needs_frame (struct symbol *symbol)
2156 struct dwarf2_locexpr_baton *dlbaton = SYMBOL_LOCATION_BATON (symbol);
2158 return dwarf2_loc_desc_needs_frame (dlbaton->data, dlbaton->size,
2162 /* Return true if DATA points to the end of a piece. END is one past
2163 the last byte in the expression. */
2166 piece_end_p (const gdb_byte *data, const gdb_byte *end)
2168 return data == end || data[0] == DW_OP_piece || data[0] == DW_OP_bit_piece;
2171 /* Nicely describe a single piece of a location, returning an updated
2172 position in the bytecode sequence. This function cannot recognize
2173 all locations; if a location is not recognized, it simply returns
2176 static const gdb_byte *
2177 locexpr_describe_location_piece (struct symbol *symbol, struct ui_file *stream,
2178 CORE_ADDR addr, struct objfile *objfile,
2179 const gdb_byte *data, const gdb_byte *end,
2180 unsigned int addr_size)
2182 struct gdbarch *gdbarch = get_objfile_arch (objfile);
2185 if (data[0] >= DW_OP_reg0 && data[0] <= DW_OP_reg31)
2187 regno = gdbarch_dwarf2_reg_to_regnum (gdbarch, data[0] - DW_OP_reg0);
2188 fprintf_filtered (stream, _("a variable in $%s"),
2189 gdbarch_register_name (gdbarch, regno));
2192 else if (data[0] == DW_OP_regx)
2196 data = read_uleb128 (data + 1, end, ®);
2197 regno = gdbarch_dwarf2_reg_to_regnum (gdbarch, reg);
2198 fprintf_filtered (stream, _("a variable in $%s"),
2199 gdbarch_register_name (gdbarch, regno));
2201 else if (data[0] == DW_OP_fbreg)
2204 struct symbol *framefunc;
2206 LONGEST frame_offset;
2207 const gdb_byte *base_data, *new_data, *save_data = data;
2209 LONGEST base_offset = 0;
2211 new_data = read_sleb128 (data + 1, end, &frame_offset);
2212 if (!piece_end_p (new_data, end))
2216 b = block_for_pc (addr);
2219 error (_("No block found for address for symbol \"%s\"."),
2220 SYMBOL_PRINT_NAME (symbol));
2222 framefunc = block_linkage_function (b);
2225 error (_("No function found for block for symbol \"%s\"."),
2226 SYMBOL_PRINT_NAME (symbol));
2228 dwarf_expr_frame_base_1 (framefunc, addr, &base_data, &base_size);
2230 if (base_data[0] >= DW_OP_breg0 && base_data[0] <= DW_OP_breg31)
2232 const gdb_byte *buf_end;
2234 frame_reg = base_data[0] - DW_OP_breg0;
2235 buf_end = read_sleb128 (base_data + 1,
2236 base_data + base_size, &base_offset);
2237 if (buf_end != base_data + base_size)
2238 error (_("Unexpected opcode after "
2239 "DW_OP_breg%u for symbol \"%s\"."),
2240 frame_reg, SYMBOL_PRINT_NAME (symbol));
2242 else if (base_data[0] >= DW_OP_reg0 && base_data[0] <= DW_OP_reg31)
2244 /* The frame base is just the register, with no offset. */
2245 frame_reg = base_data[0] - DW_OP_reg0;
2250 /* We don't know what to do with the frame base expression,
2251 so we can't trace this variable; give up. */
2255 regno = gdbarch_dwarf2_reg_to_regnum (gdbarch, frame_reg);
2257 fprintf_filtered (stream,
2258 _("a variable at frame base reg $%s offset %s+%s"),
2259 gdbarch_register_name (gdbarch, regno),
2260 plongest (base_offset), plongest (frame_offset));
2262 else if (data[0] >= DW_OP_breg0 && data[0] <= DW_OP_breg31
2263 && piece_end_p (data, end))
2267 regno = gdbarch_dwarf2_reg_to_regnum (gdbarch, data[0] - DW_OP_breg0);
2269 data = read_sleb128 (data + 1, end, &offset);
2271 fprintf_filtered (stream,
2272 _("a variable at offset %s from base reg $%s"),
2274 gdbarch_register_name (gdbarch, regno));
2277 /* The location expression for a TLS variable looks like this (on a
2280 DW_AT_location : 10 byte block: 3 4 0 0 0 0 0 0 0 e0
2281 (DW_OP_addr: 4; DW_OP_GNU_push_tls_address)
2283 0x3 is the encoding for DW_OP_addr, which has an operand as long
2284 as the size of an address on the target machine (here is 8
2285 bytes). Note that more recent version of GCC emit DW_OP_const4u
2286 or DW_OP_const8u, depending on address size, rather than
2287 DW_OP_addr. 0xe0 is the encoding for DW_OP_GNU_push_tls_address.
2288 The operand represents the offset at which the variable is within
2289 the thread local storage. */
2291 else if (data + 1 + addr_size < end
2292 && (data[0] == DW_OP_addr
2293 || (addr_size == 4 && data[0] == DW_OP_const4u)
2294 || (addr_size == 8 && data[0] == DW_OP_const8u))
2295 && data[1 + addr_size] == DW_OP_GNU_push_tls_address
2296 && piece_end_p (data + 2 + addr_size, end))
2299 offset = extract_unsigned_integer (data + 1, addr_size,
2300 gdbarch_byte_order (gdbarch));
2302 fprintf_filtered (stream,
2303 _("a thread-local variable at offset 0x%s "
2304 "in the thread-local storage for `%s'"),
2305 phex_nz (offset, addr_size), objfile->name);
2307 data += 1 + addr_size + 1;
2309 else if (data[0] >= DW_OP_lit0
2310 && data[0] <= DW_OP_lit31
2312 && data[1] == DW_OP_stack_value)
2314 fprintf_filtered (stream, _("the constant %d"), data[0] - DW_OP_lit0);
2321 /* Disassemble an expression, stopping at the end of a piece or at the
2322 end of the expression. Returns a pointer to the next unread byte
2323 in the input expression. If ALL is nonzero, then this function
2324 will keep going until it reaches the end of the expression. */
2326 static const gdb_byte *
2327 disassemble_dwarf_expression (struct ui_file *stream,
2328 struct gdbarch *arch, unsigned int addr_size,
2330 const gdb_byte *data, const gdb_byte *end,
2333 const gdb_byte *start = data;
2335 fprintf_filtered (stream, _("a complex DWARF expression:\n"));
2339 || (data[0] != DW_OP_piece && data[0] != DW_OP_bit_piece)))
2341 enum dwarf_location_atom op = *data++;
2346 name = dwarf_stack_op_name (op);
2349 error (_("Unrecognized DWARF opcode 0x%02x at %ld"),
2350 op, (long) (data - start));
2351 fprintf_filtered (stream, " % 4ld: %s", (long) (data - start), name);
2356 ul = extract_unsigned_integer (data, addr_size,
2357 gdbarch_byte_order (arch));
2359 fprintf_filtered (stream, " 0x%s", phex_nz (ul, addr_size));
2363 ul = extract_unsigned_integer (data, 1, gdbarch_byte_order (arch));
2365 fprintf_filtered (stream, " %s", pulongest (ul));
2368 l = extract_signed_integer (data, 1, gdbarch_byte_order (arch));
2370 fprintf_filtered (stream, " %s", plongest (l));
2373 ul = extract_unsigned_integer (data, 2, gdbarch_byte_order (arch));
2375 fprintf_filtered (stream, " %s", pulongest (ul));
2378 l = extract_signed_integer (data, 2, gdbarch_byte_order (arch));
2380 fprintf_filtered (stream, " %s", plongest (l));
2383 ul = extract_unsigned_integer (data, 4, gdbarch_byte_order (arch));
2385 fprintf_filtered (stream, " %s", pulongest (ul));
2388 l = extract_signed_integer (data, 4, gdbarch_byte_order (arch));
2390 fprintf_filtered (stream, " %s", plongest (l));
2393 ul = extract_unsigned_integer (data, 8, gdbarch_byte_order (arch));
2395 fprintf_filtered (stream, " %s", pulongest (ul));
2398 l = extract_signed_integer (data, 8, gdbarch_byte_order (arch));
2400 fprintf_filtered (stream, " %s", plongest (l));
2403 data = read_uleb128 (data, end, &ul);
2404 fprintf_filtered (stream, " %s", pulongest (ul));
2407 data = read_sleb128 (data, end, &l);
2408 fprintf_filtered (stream, " %s", plongest (l));
2443 fprintf_filtered (stream, " [$%s]",
2444 gdbarch_register_name (arch, op - DW_OP_reg0));
2448 data = read_uleb128 (data, end, &ul);
2449 fprintf_filtered (stream, " %s [$%s]", pulongest (ul),
2450 gdbarch_register_name (arch, (int) ul));
2453 case DW_OP_implicit_value:
2454 data = read_uleb128 (data, end, &ul);
2456 fprintf_filtered (stream, " %s", pulongest (ul));
2491 data = read_sleb128 (data, end, &l);
2492 fprintf_filtered (stream, " %s [$%s]", plongest (l),
2493 gdbarch_register_name (arch, op - DW_OP_breg0));
2497 data = read_uleb128 (data, end, &ul);
2498 data = read_sleb128 (data, end, &l);
2499 fprintf_filtered (stream, " register %s [$%s] offset %s",
2501 gdbarch_register_name (arch, (int) ul),
2506 data = read_sleb128 (data, end, &l);
2507 fprintf_filtered (stream, " %s", plongest (l));
2510 case DW_OP_xderef_size:
2511 case DW_OP_deref_size:
2513 fprintf_filtered (stream, " %d", *data);
2517 case DW_OP_plus_uconst:
2518 data = read_uleb128 (data, end, &ul);
2519 fprintf_filtered (stream, " %s", pulongest (ul));
2523 l = extract_signed_integer (data, 2, gdbarch_byte_order (arch));
2525 fprintf_filtered (stream, " to %ld",
2526 (long) (data + l - start));
2530 l = extract_signed_integer (data, 2, gdbarch_byte_order (arch));
2532 fprintf_filtered (stream, " %ld",
2533 (long) (data + l - start));
2537 ul = extract_unsigned_integer (data, 2, gdbarch_byte_order (arch));
2539 fprintf_filtered (stream, " offset %s", phex_nz (ul, 2));
2543 ul = extract_unsigned_integer (data, 4, gdbarch_byte_order (arch));
2545 fprintf_filtered (stream, " offset %s", phex_nz (ul, 4));
2548 case DW_OP_call_ref:
2549 ul = extract_unsigned_integer (data, offset_size,
2550 gdbarch_byte_order (arch));
2551 data += offset_size;
2552 fprintf_filtered (stream, " offset %s", phex_nz (ul, offset_size));
2556 data = read_uleb128 (data, end, &ul);
2557 fprintf_filtered (stream, " %s (bytes)", pulongest (ul));
2560 case DW_OP_bit_piece:
2564 data = read_uleb128 (data, end, &ul);
2565 data = read_uleb128 (data, end, &offset);
2566 fprintf_filtered (stream, " size %s offset %s (bits)",
2567 pulongest (ul), pulongest (offset));
2571 case DW_OP_GNU_implicit_pointer:
2573 ul = extract_unsigned_integer (data, offset_size,
2574 gdbarch_byte_order (arch));
2575 data += offset_size;
2577 data = read_sleb128 (data, end, &l);
2579 fprintf_filtered (stream, " DIE %s offset %s",
2580 phex_nz (ul, offset_size),
2586 fprintf_filtered (stream, "\n");
2592 /* Describe a single location, which may in turn consist of multiple
2596 locexpr_describe_location_1 (struct symbol *symbol, CORE_ADDR addr,
2597 struct ui_file *stream,
2598 const gdb_byte *data, int size,
2599 struct objfile *objfile, unsigned int addr_size,
2602 const gdb_byte *end = data + size;
2603 int first_piece = 1, bad = 0;
2607 const gdb_byte *here = data;
2608 int disassemble = 1;
2613 fprintf_filtered (stream, _(", and "));
2615 if (!dwarf2_always_disassemble)
2617 data = locexpr_describe_location_piece (symbol, stream,
2619 data, end, addr_size);
2620 /* If we printed anything, or if we have an empty piece,
2621 then don't disassemble. */
2623 || data[0] == DW_OP_piece
2624 || data[0] == DW_OP_bit_piece)
2628 data = disassemble_dwarf_expression (stream,
2629 get_objfile_arch (objfile),
2630 addr_size, offset_size, data, end,
2631 dwarf2_always_disassemble);
2635 int empty = data == here;
2638 fprintf_filtered (stream, " ");
2639 if (data[0] == DW_OP_piece)
2643 data = read_uleb128 (data + 1, end, &bytes);
2646 fprintf_filtered (stream, _("an empty %s-byte piece"),
2649 fprintf_filtered (stream, _(" [%s-byte piece]"),
2652 else if (data[0] == DW_OP_bit_piece)
2654 ULONGEST bits, offset;
2656 data = read_uleb128 (data + 1, end, &bits);
2657 data = read_uleb128 (data, end, &offset);
2660 fprintf_filtered (stream,
2661 _("an empty %s-bit piece"),
2664 fprintf_filtered (stream,
2665 _(" [%s-bit piece, offset %s bits]"),
2666 pulongest (bits), pulongest (offset));
2676 if (bad || data > end)
2677 error (_("Corrupted DWARF2 expression for \"%s\"."),
2678 SYMBOL_PRINT_NAME (symbol));
2681 /* Print a natural-language description of SYMBOL to STREAM. This
2682 version is for a symbol with a single location. */
2685 locexpr_describe_location (struct symbol *symbol, CORE_ADDR addr,
2686 struct ui_file *stream)
2688 struct dwarf2_locexpr_baton *dlbaton = SYMBOL_LOCATION_BATON (symbol);
2689 struct objfile *objfile = dwarf2_per_cu_objfile (dlbaton->per_cu);
2690 unsigned int addr_size = dwarf2_per_cu_addr_size (dlbaton->per_cu);
2691 int offset_size = dwarf2_per_cu_offset_size (dlbaton->per_cu);
2693 locexpr_describe_location_1 (symbol, addr, stream,
2694 dlbaton->data, dlbaton->size,
2695 objfile, addr_size, offset_size);
2698 /* Describe the location of SYMBOL as an agent value in VALUE, generating
2699 any necessary bytecode in AX. */
2702 locexpr_tracepoint_var_ref (struct symbol *symbol, struct gdbarch *gdbarch,
2703 struct agent_expr *ax, struct axs_value *value)
2705 struct dwarf2_locexpr_baton *dlbaton = SYMBOL_LOCATION_BATON (symbol);
2706 unsigned int addr_size = dwarf2_per_cu_addr_size (dlbaton->per_cu);
2708 if (dlbaton->data == NULL || dlbaton->size == 0)
2709 value->optimized_out = 1;
2711 dwarf2_compile_expr_to_ax (ax, value, gdbarch, addr_size,
2712 dlbaton->data, dlbaton->data + dlbaton->size,
2716 /* The set of location functions used with the DWARF-2 expression
2718 const struct symbol_computed_ops dwarf2_locexpr_funcs = {
2719 locexpr_read_variable,
2720 locexpr_read_needs_frame,
2721 locexpr_describe_location,
2722 locexpr_tracepoint_var_ref
2726 /* Wrapper functions for location lists. These generally find
2727 the appropriate location expression and call something above. */
2729 /* Return the value of SYMBOL in FRAME using the DWARF-2 expression
2730 evaluator to calculate the location. */
2731 static struct value *
2732 loclist_read_variable (struct symbol *symbol, struct frame_info *frame)
2734 struct dwarf2_loclist_baton *dlbaton = SYMBOL_LOCATION_BATON (symbol);
2736 const gdb_byte *data;
2738 CORE_ADDR pc = frame ? get_frame_address_in_block (frame) : 0;
2740 data = dwarf2_find_location_expression (dlbaton, &size, pc);
2743 val = allocate_value (SYMBOL_TYPE (symbol));
2744 VALUE_LVAL (val) = not_lval;
2745 set_value_optimized_out (val, 1);
2748 val = dwarf2_evaluate_loc_desc (SYMBOL_TYPE (symbol), frame, data, size,
2754 /* Return non-zero iff we need a frame to evaluate SYMBOL. */
2756 loclist_read_needs_frame (struct symbol *symbol)
2758 /* If there's a location list, then assume we need to have a frame
2759 to choose the appropriate location expression. With tracking of
2760 global variables this is not necessarily true, but such tracking
2761 is disabled in GCC at the moment until we figure out how to
2767 /* Print a natural-language description of SYMBOL to STREAM. This
2768 version applies when there is a list of different locations, each
2769 with a specified address range. */
2772 loclist_describe_location (struct symbol *symbol, CORE_ADDR addr,
2773 struct ui_file *stream)
2775 struct dwarf2_loclist_baton *dlbaton = SYMBOL_LOCATION_BATON (symbol);
2776 CORE_ADDR low, high;
2777 const gdb_byte *loc_ptr, *buf_end;
2778 int length, first = 1;
2779 struct objfile *objfile = dwarf2_per_cu_objfile (dlbaton->per_cu);
2780 struct gdbarch *gdbarch = get_objfile_arch (objfile);
2781 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
2782 unsigned int addr_size = dwarf2_per_cu_addr_size (dlbaton->per_cu);
2783 int offset_size = dwarf2_per_cu_offset_size (dlbaton->per_cu);
2784 int signed_addr_p = bfd_get_sign_extend_vma (objfile->obfd);
2785 CORE_ADDR base_mask = ~(~(CORE_ADDR)1 << (addr_size * 8 - 1));
2786 /* Adjust base_address for relocatable objects. */
2787 CORE_ADDR base_offset = dwarf2_per_cu_text_offset (dlbaton->per_cu);
2788 CORE_ADDR base_address = dlbaton->base_address + base_offset;
2790 loc_ptr = dlbaton->data;
2791 buf_end = dlbaton->data + dlbaton->size;
2793 fprintf_filtered (stream, _("multi-location:\n"));
2795 /* Iterate through locations until we run out. */
2798 if (buf_end - loc_ptr < 2 * addr_size)
2799 error (_("Corrupted DWARF expression for symbol \"%s\"."),
2800 SYMBOL_PRINT_NAME (symbol));
2803 low = extract_signed_integer (loc_ptr, addr_size, byte_order);
2805 low = extract_unsigned_integer (loc_ptr, addr_size, byte_order);
2806 loc_ptr += addr_size;
2809 high = extract_signed_integer (loc_ptr, addr_size, byte_order);
2811 high = extract_unsigned_integer (loc_ptr, addr_size, byte_order);
2812 loc_ptr += addr_size;
2814 /* A base-address-selection entry. */
2815 if ((low & base_mask) == base_mask)
2817 base_address = high + base_offset;
2818 fprintf_filtered (stream, _(" Base address %s"),
2819 paddress (gdbarch, base_address));
2823 /* An end-of-list entry. */
2824 if (low == 0 && high == 0)
2827 /* Otherwise, a location expression entry. */
2828 low += base_address;
2829 high += base_address;
2831 length = extract_unsigned_integer (loc_ptr, 2, byte_order);
2834 /* (It would improve readability to print only the minimum
2835 necessary digits of the second number of the range.) */
2836 fprintf_filtered (stream, _(" Range %s-%s: "),
2837 paddress (gdbarch, low), paddress (gdbarch, high));
2839 /* Now describe this particular location. */
2840 locexpr_describe_location_1 (symbol, low, stream, loc_ptr, length,
2841 objfile, addr_size, offset_size);
2843 fprintf_filtered (stream, "\n");
2849 /* Describe the location of SYMBOL as an agent value in VALUE, generating
2850 any necessary bytecode in AX. */
2852 loclist_tracepoint_var_ref (struct symbol *symbol, struct gdbarch *gdbarch,
2853 struct agent_expr *ax, struct axs_value *value)
2855 struct dwarf2_loclist_baton *dlbaton = SYMBOL_LOCATION_BATON (symbol);
2856 const gdb_byte *data;
2858 unsigned int addr_size = dwarf2_per_cu_addr_size (dlbaton->per_cu);
2860 data = dwarf2_find_location_expression (dlbaton, &size, ax->scope);
2861 if (data == NULL || size == 0)
2862 value->optimized_out = 1;
2864 dwarf2_compile_expr_to_ax (ax, value, gdbarch, addr_size, data, data + size,
2868 /* The set of location functions used with the DWARF-2 expression
2869 evaluator and location lists. */
2870 const struct symbol_computed_ops dwarf2_loclist_funcs = {
2871 loclist_read_variable,
2872 loclist_read_needs_frame,
2873 loclist_describe_location,
2874 loclist_tracepoint_var_ref