1 /* DWARF 2 location expression support for GDB.
3 Copyright (C) 2003-2018 Free Software Foundation, Inc.
5 Contributed by Daniel Jacobowitz, MontaVista Software, Inc.
7 This file is part of GDB.
9 This program is free software; you can redistribute it and/or modify
10 it under the terms of the GNU General Public License as published by
11 the Free Software Foundation; either version 3 of the License, or
12 (at your option) any later version.
14 This program is distributed in the hope that it will be useful,
15 but WITHOUT ANY WARRANTY; without even the implied warranty of
16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 GNU General Public License for more details.
19 You should have received a copy of the GNU General Public License
20 along with this program. If not, see <http://www.gnu.org/licenses/>. */
35 #include "complaints.h"
37 #include "dwarf2expr.h"
38 #include "dwarf2loc.h"
39 #include "dwarf2-frame.h"
40 #include "compile/compile.h"
44 #include <unordered_set>
45 #include "common/underlying.h"
46 #include "common/byte-vector.h"
48 extern int dwarf_always_disassemble;
50 static struct value *dwarf2_evaluate_loc_desc_full (struct type *type,
51 struct frame_info *frame,
54 struct dwarf2_per_cu_data *per_cu,
55 struct type *subobj_type,
56 LONGEST subobj_byte_offset);
58 static struct call_site_parameter *dwarf_expr_reg_to_entry_parameter
59 (struct frame_info *frame,
60 enum call_site_parameter_kind kind,
61 union call_site_parameter_u kind_u,
62 struct dwarf2_per_cu_data **per_cu_return);
64 static struct value *indirect_synthetic_pointer
65 (sect_offset die, LONGEST byte_offset,
66 struct dwarf2_per_cu_data *per_cu,
67 struct frame_info *frame,
68 struct type *type, bool resolve_abstract_p = false);
70 /* Until these have formal names, we define these here.
71 ref: http://gcc.gnu.org/wiki/DebugFission
72 Each entry in .debug_loc.dwo begins with a byte that describes the entry,
73 and is then followed by data specific to that entry. */
77 /* Indicates the end of the list of entries. */
78 DEBUG_LOC_END_OF_LIST = 0,
80 /* This is followed by an unsigned LEB128 number that is an index into
81 .debug_addr and specifies the base address for all following entries. */
82 DEBUG_LOC_BASE_ADDRESS = 1,
84 /* This is followed by two unsigned LEB128 numbers that are indices into
85 .debug_addr and specify the beginning and ending addresses, and then
86 a normal location expression as in .debug_loc. */
87 DEBUG_LOC_START_END = 2,
89 /* This is followed by an unsigned LEB128 number that is an index into
90 .debug_addr and specifies the beginning address, and a 4 byte unsigned
91 number that specifies the length, and then a normal location expression
93 DEBUG_LOC_START_LENGTH = 3,
95 /* An internal value indicating there is insufficient data. */
96 DEBUG_LOC_BUFFER_OVERFLOW = -1,
98 /* An internal value indicating an invalid kind of entry was found. */
99 DEBUG_LOC_INVALID_ENTRY = -2
102 /* Helper function which throws an error if a synthetic pointer is
106 invalid_synthetic_pointer (void)
108 error (_("access outside bounds of object "
109 "referenced via synthetic pointer"));
112 /* Decode the addresses in a non-dwo .debug_loc entry.
113 A pointer to the next byte to examine is returned in *NEW_PTR.
114 The encoded low,high addresses are return in *LOW,*HIGH.
115 The result indicates the kind of entry found. */
117 static enum debug_loc_kind
118 decode_debug_loc_addresses (const gdb_byte *loc_ptr, const gdb_byte *buf_end,
119 const gdb_byte **new_ptr,
120 CORE_ADDR *low, CORE_ADDR *high,
121 enum bfd_endian byte_order,
122 unsigned int addr_size,
125 CORE_ADDR base_mask = ~(~(CORE_ADDR)1 << (addr_size * 8 - 1));
127 if (buf_end - loc_ptr < 2 * addr_size)
128 return DEBUG_LOC_BUFFER_OVERFLOW;
131 *low = extract_signed_integer (loc_ptr, addr_size, byte_order);
133 *low = extract_unsigned_integer (loc_ptr, addr_size, byte_order);
134 loc_ptr += addr_size;
137 *high = extract_signed_integer (loc_ptr, addr_size, byte_order);
139 *high = extract_unsigned_integer (loc_ptr, addr_size, byte_order);
140 loc_ptr += addr_size;
144 /* A base-address-selection entry. */
145 if ((*low & base_mask) == base_mask)
146 return DEBUG_LOC_BASE_ADDRESS;
148 /* An end-of-list entry. */
149 if (*low == 0 && *high == 0)
150 return DEBUG_LOC_END_OF_LIST;
152 return DEBUG_LOC_START_END;
155 /* Decode the addresses in .debug_loclists entry.
156 A pointer to the next byte to examine is returned in *NEW_PTR.
157 The encoded low,high addresses are return in *LOW,*HIGH.
158 The result indicates the kind of entry found. */
160 static enum debug_loc_kind
161 decode_debug_loclists_addresses (struct dwarf2_per_cu_data *per_cu,
162 const gdb_byte *loc_ptr,
163 const gdb_byte *buf_end,
164 const gdb_byte **new_ptr,
165 CORE_ADDR *low, CORE_ADDR *high,
166 enum bfd_endian byte_order,
167 unsigned int addr_size,
172 if (loc_ptr == buf_end)
173 return DEBUG_LOC_BUFFER_OVERFLOW;
177 case DW_LLE_end_of_list:
179 return DEBUG_LOC_END_OF_LIST;
180 case DW_LLE_base_address:
181 if (loc_ptr + addr_size > buf_end)
182 return DEBUG_LOC_BUFFER_OVERFLOW;
184 *high = extract_signed_integer (loc_ptr, addr_size, byte_order);
186 *high = extract_unsigned_integer (loc_ptr, addr_size, byte_order);
187 loc_ptr += addr_size;
189 return DEBUG_LOC_BASE_ADDRESS;
190 case DW_LLE_offset_pair:
191 loc_ptr = gdb_read_uleb128 (loc_ptr, buf_end, &u64);
193 return DEBUG_LOC_BUFFER_OVERFLOW;
195 loc_ptr = gdb_read_uleb128 (loc_ptr, buf_end, &u64);
197 return DEBUG_LOC_BUFFER_OVERFLOW;
200 return DEBUG_LOC_START_END;
202 return DEBUG_LOC_INVALID_ENTRY;
206 /* Decode the addresses in .debug_loc.dwo entry.
207 A pointer to the next byte to examine is returned in *NEW_PTR.
208 The encoded low,high addresses are return in *LOW,*HIGH.
209 The result indicates the kind of entry found. */
211 static enum debug_loc_kind
212 decode_debug_loc_dwo_addresses (struct dwarf2_per_cu_data *per_cu,
213 const gdb_byte *loc_ptr,
214 const gdb_byte *buf_end,
215 const gdb_byte **new_ptr,
216 CORE_ADDR *low, CORE_ADDR *high,
217 enum bfd_endian byte_order)
219 uint64_t low_index, high_index;
221 if (loc_ptr == buf_end)
222 return DEBUG_LOC_BUFFER_OVERFLOW;
226 case DW_LLE_GNU_end_of_list_entry:
228 return DEBUG_LOC_END_OF_LIST;
229 case DW_LLE_GNU_base_address_selection_entry:
231 loc_ptr = gdb_read_uleb128 (loc_ptr, buf_end, &high_index);
233 return DEBUG_LOC_BUFFER_OVERFLOW;
234 *high = dwarf2_read_addr_index (per_cu, high_index);
236 return DEBUG_LOC_BASE_ADDRESS;
237 case DW_LLE_GNU_start_end_entry:
238 loc_ptr = gdb_read_uleb128 (loc_ptr, buf_end, &low_index);
240 return DEBUG_LOC_BUFFER_OVERFLOW;
241 *low = dwarf2_read_addr_index (per_cu, low_index);
242 loc_ptr = gdb_read_uleb128 (loc_ptr, buf_end, &high_index);
244 return DEBUG_LOC_BUFFER_OVERFLOW;
245 *high = dwarf2_read_addr_index (per_cu, high_index);
247 return DEBUG_LOC_START_END;
248 case DW_LLE_GNU_start_length_entry:
249 loc_ptr = gdb_read_uleb128 (loc_ptr, buf_end, &low_index);
251 return DEBUG_LOC_BUFFER_OVERFLOW;
252 *low = dwarf2_read_addr_index (per_cu, low_index);
253 if (loc_ptr + 4 > buf_end)
254 return DEBUG_LOC_BUFFER_OVERFLOW;
256 *high += extract_unsigned_integer (loc_ptr, 4, byte_order);
257 *new_ptr = loc_ptr + 4;
258 return DEBUG_LOC_START_LENGTH;
260 return DEBUG_LOC_INVALID_ENTRY;
264 /* A function for dealing with location lists. Given a
265 symbol baton (BATON) and a pc value (PC), find the appropriate
266 location expression, set *LOCEXPR_LENGTH, and return a pointer
267 to the beginning of the expression. Returns NULL on failure.
269 For now, only return the first matching location expression; there
270 can be more than one in the list. */
273 dwarf2_find_location_expression (struct dwarf2_loclist_baton *baton,
274 size_t *locexpr_length, CORE_ADDR pc)
276 struct objfile *objfile = dwarf2_per_cu_objfile (baton->per_cu);
277 struct gdbarch *gdbarch = get_objfile_arch (objfile);
278 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
279 unsigned int addr_size = dwarf2_per_cu_addr_size (baton->per_cu);
280 int signed_addr_p = bfd_get_sign_extend_vma (objfile->obfd);
281 /* Adjust base_address for relocatable objects. */
282 CORE_ADDR base_offset = dwarf2_per_cu_text_offset (baton->per_cu);
283 CORE_ADDR base_address = baton->base_address + base_offset;
284 const gdb_byte *loc_ptr, *buf_end;
286 loc_ptr = baton->data;
287 buf_end = baton->data + baton->size;
291 CORE_ADDR low = 0, high = 0; /* init for gcc -Wall */
293 enum debug_loc_kind kind;
294 const gdb_byte *new_ptr = NULL; /* init for gcc -Wall */
297 kind = decode_debug_loc_dwo_addresses (baton->per_cu,
298 loc_ptr, buf_end, &new_ptr,
299 &low, &high, byte_order);
300 else if (dwarf2_version (baton->per_cu) < 5)
301 kind = decode_debug_loc_addresses (loc_ptr, buf_end, &new_ptr,
303 byte_order, addr_size,
306 kind = decode_debug_loclists_addresses (baton->per_cu,
307 loc_ptr, buf_end, &new_ptr,
308 &low, &high, byte_order,
309 addr_size, signed_addr_p);
314 case DEBUG_LOC_END_OF_LIST:
317 case DEBUG_LOC_BASE_ADDRESS:
318 base_address = high + base_offset;
320 case DEBUG_LOC_START_END:
321 case DEBUG_LOC_START_LENGTH:
323 case DEBUG_LOC_BUFFER_OVERFLOW:
324 case DEBUG_LOC_INVALID_ENTRY:
325 error (_("dwarf2_find_location_expression: "
326 "Corrupted DWARF expression."));
328 gdb_assert_not_reached ("bad debug_loc_kind");
331 /* Otherwise, a location expression entry.
332 If the entry is from a DWO, don't add base address: the entry is from
333 .debug_addr which already has the DWARF "base address". We still add
334 base_offset in case we're debugging a PIE executable. */
343 high += base_address;
346 if (dwarf2_version (baton->per_cu) < 5)
348 length = extract_unsigned_integer (loc_ptr, 2, byte_order);
353 unsigned int bytes_read;
355 length = read_unsigned_leb128 (NULL, loc_ptr, &bytes_read);
356 loc_ptr += bytes_read;
359 if (low == high && pc == low)
361 /* This is entry PC record present only at entry point
362 of a function. Verify it is really the function entry point. */
364 const struct block *pc_block = block_for_pc (pc);
365 struct symbol *pc_func = NULL;
368 pc_func = block_linkage_function (pc_block);
370 if (pc_func && pc == BLOCK_ENTRY_PC (SYMBOL_BLOCK_VALUE (pc_func)))
372 *locexpr_length = length;
377 if (pc >= low && pc < high)
379 *locexpr_length = length;
387 /* This is the baton used when performing dwarf2 expression
389 struct dwarf_expr_baton
391 struct frame_info *frame;
392 struct dwarf2_per_cu_data *per_cu;
393 CORE_ADDR obj_address;
396 /* Implement find_frame_base_location method for LOC_BLOCK functions using
397 DWARF expression for its DW_AT_frame_base. */
400 locexpr_find_frame_base_location (struct symbol *framefunc, CORE_ADDR pc,
401 const gdb_byte **start, size_t *length)
403 struct dwarf2_locexpr_baton *symbaton
404 = (struct dwarf2_locexpr_baton *) SYMBOL_LOCATION_BATON (framefunc);
406 *length = symbaton->size;
407 *start = symbaton->data;
410 /* Implement the struct symbol_block_ops::get_frame_base method for
411 LOC_BLOCK functions using a DWARF expression as its DW_AT_frame_base. */
414 locexpr_get_frame_base (struct symbol *framefunc, struct frame_info *frame)
416 struct gdbarch *gdbarch;
418 struct dwarf2_locexpr_baton *dlbaton;
419 const gdb_byte *start;
421 struct value *result;
423 /* If this method is called, then FRAMEFUNC is supposed to be a DWARF block.
424 Thus, it's supposed to provide the find_frame_base_location method as
426 gdb_assert (SYMBOL_BLOCK_OPS (framefunc)->find_frame_base_location != NULL);
428 gdbarch = get_frame_arch (frame);
429 type = builtin_type (gdbarch)->builtin_data_ptr;
430 dlbaton = (struct dwarf2_locexpr_baton *) SYMBOL_LOCATION_BATON (framefunc);
432 SYMBOL_BLOCK_OPS (framefunc)->find_frame_base_location
433 (framefunc, get_frame_pc (frame), &start, &length);
434 result = dwarf2_evaluate_loc_desc (type, frame, start, length,
437 /* The DW_AT_frame_base attribute contains a location description which
438 computes the base address itself. However, the call to
439 dwarf2_evaluate_loc_desc returns a value representing a variable at
440 that address. The frame base address is thus this variable's
442 return value_address (result);
445 /* Vector for inferior functions as represented by LOC_BLOCK, if the inferior
446 function uses DWARF expression for its DW_AT_frame_base. */
448 const struct symbol_block_ops dwarf2_block_frame_base_locexpr_funcs =
450 locexpr_find_frame_base_location,
451 locexpr_get_frame_base
454 /* Implement find_frame_base_location method for LOC_BLOCK functions using
455 DWARF location list for its DW_AT_frame_base. */
458 loclist_find_frame_base_location (struct symbol *framefunc, CORE_ADDR pc,
459 const gdb_byte **start, size_t *length)
461 struct dwarf2_loclist_baton *symbaton
462 = (struct dwarf2_loclist_baton *) SYMBOL_LOCATION_BATON (framefunc);
464 *start = dwarf2_find_location_expression (symbaton, length, pc);
467 /* Implement the struct symbol_block_ops::get_frame_base method for
468 LOC_BLOCK functions using a DWARF location list as its DW_AT_frame_base. */
471 loclist_get_frame_base (struct symbol *framefunc, struct frame_info *frame)
473 struct gdbarch *gdbarch;
475 struct dwarf2_loclist_baton *dlbaton;
476 const gdb_byte *start;
478 struct value *result;
480 /* If this method is called, then FRAMEFUNC is supposed to be a DWARF block.
481 Thus, it's supposed to provide the find_frame_base_location method as
483 gdb_assert (SYMBOL_BLOCK_OPS (framefunc)->find_frame_base_location != NULL);
485 gdbarch = get_frame_arch (frame);
486 type = builtin_type (gdbarch)->builtin_data_ptr;
487 dlbaton = (struct dwarf2_loclist_baton *) SYMBOL_LOCATION_BATON (framefunc);
489 SYMBOL_BLOCK_OPS (framefunc)->find_frame_base_location
490 (framefunc, get_frame_pc (frame), &start, &length);
491 result = dwarf2_evaluate_loc_desc (type, frame, start, length,
494 /* The DW_AT_frame_base attribute contains a location description which
495 computes the base address itself. However, the call to
496 dwarf2_evaluate_loc_desc returns a value representing a variable at
497 that address. The frame base address is thus this variable's
499 return value_address (result);
502 /* Vector for inferior functions as represented by LOC_BLOCK, if the inferior
503 function uses DWARF location list for its DW_AT_frame_base. */
505 const struct symbol_block_ops dwarf2_block_frame_base_loclist_funcs =
507 loclist_find_frame_base_location,
508 loclist_get_frame_base
511 /* See dwarf2loc.h. */
514 func_get_frame_base_dwarf_block (struct symbol *framefunc, CORE_ADDR pc,
515 const gdb_byte **start, size_t *length)
517 if (SYMBOL_BLOCK_OPS (framefunc) != NULL)
519 const struct symbol_block_ops *ops_block = SYMBOL_BLOCK_OPS (framefunc);
521 ops_block->find_frame_base_location (framefunc, pc, start, length);
527 error (_("Could not find the frame base for \"%s\"."),
528 SYMBOL_NATURAL_NAME (framefunc));
532 get_frame_pc_for_per_cu_dwarf_call (void *baton)
534 dwarf_expr_context *ctx = (dwarf_expr_context *) baton;
536 return ctx->get_frame_pc ();
540 per_cu_dwarf_call (struct dwarf_expr_context *ctx, cu_offset die_offset,
541 struct dwarf2_per_cu_data *per_cu)
543 struct dwarf2_locexpr_baton block;
545 block = dwarf2_fetch_die_loc_cu_off (die_offset, per_cu,
546 get_frame_pc_for_per_cu_dwarf_call,
549 /* DW_OP_call_ref is currently not supported. */
550 gdb_assert (block.per_cu == per_cu);
552 ctx->eval (block.data, block.size);
555 /* Given context CTX, section offset SECT_OFF, and compilation unit
556 data PER_CU, execute the "variable value" operation on the DIE
557 found at SECT_OFF. */
559 static struct value *
560 sect_variable_value (struct dwarf_expr_context *ctx, sect_offset sect_off,
561 struct dwarf2_per_cu_data *per_cu)
563 struct type *die_type = dwarf2_fetch_die_type_sect_off (sect_off, per_cu);
565 if (die_type == NULL)
566 error (_("Bad DW_OP_GNU_variable_value DIE."));
568 /* Note: Things still work when the following test is removed. This
569 test and error is here to conform to the proposed specification. */
570 if (TYPE_CODE (die_type) != TYPE_CODE_INT
571 && TYPE_CODE (die_type) != TYPE_CODE_PTR)
572 error (_("Type of DW_OP_GNU_variable_value DIE must be an integer or pointer."));
574 struct type *type = lookup_pointer_type (die_type);
575 struct frame_info *frame = get_selected_frame (_("No frame selected."));
576 return indirect_synthetic_pointer (sect_off, 0, per_cu, frame, type, true);
579 class dwarf_evaluate_loc_desc : public dwarf_expr_context
583 struct frame_info *frame;
584 struct dwarf2_per_cu_data *per_cu;
585 CORE_ADDR obj_address;
587 /* Helper function for dwarf2_evaluate_loc_desc. Computes the CFA for
588 the frame in BATON. */
590 CORE_ADDR get_frame_cfa () override
592 return dwarf2_frame_cfa (frame);
595 /* Helper function for dwarf2_evaluate_loc_desc. Computes the PC for
596 the frame in BATON. */
598 CORE_ADDR get_frame_pc () override
600 return get_frame_address_in_block (frame);
603 /* Using the objfile specified in BATON, find the address for the
604 current thread's thread-local storage with offset OFFSET. */
605 CORE_ADDR get_tls_address (CORE_ADDR offset) override
607 struct objfile *objfile = dwarf2_per_cu_objfile (per_cu);
609 return target_translate_tls_address (objfile, offset);
612 /* Helper interface of per_cu_dwarf_call for
613 dwarf2_evaluate_loc_desc. */
615 void dwarf_call (cu_offset die_offset) override
617 per_cu_dwarf_call (this, die_offset, per_cu);
620 /* Helper interface of sect_variable_value for
621 dwarf2_evaluate_loc_desc. */
623 struct value *dwarf_variable_value (sect_offset sect_off) override
625 return sect_variable_value (this, sect_off, per_cu);
628 struct type *get_base_type (cu_offset die_offset, int size) override
630 struct type *result = dwarf2_get_die_type (die_offset, per_cu);
632 error (_("Could not find type for DW_OP_const_type"));
633 if (size != 0 && TYPE_LENGTH (result) != size)
634 error (_("DW_OP_const_type has different sizes for type and data"));
638 /* Callback function for dwarf2_evaluate_loc_desc.
639 Fetch the address indexed by DW_OP_GNU_addr_index. */
641 CORE_ADDR get_addr_index (unsigned int index) override
643 return dwarf2_read_addr_index (per_cu, index);
646 /* Callback function for get_object_address. Return the address of the VLA
649 CORE_ADDR get_object_address () override
651 if (obj_address == 0)
652 error (_("Location address is not set."));
656 /* Execute DWARF block of call_site_parameter which matches KIND and
657 KIND_U. Choose DEREF_SIZE value of that parameter. Search
658 caller of this objects's frame.
660 The caller can be from a different CU - per_cu_dwarf_call
661 implementation can be more simple as it does not support cross-CU
664 void push_dwarf_reg_entry_value (enum call_site_parameter_kind kind,
665 union call_site_parameter_u kind_u,
666 int deref_size) override
668 struct frame_info *caller_frame;
669 struct dwarf2_per_cu_data *caller_per_cu;
670 struct call_site_parameter *parameter;
671 const gdb_byte *data_src;
674 caller_frame = get_prev_frame (frame);
676 parameter = dwarf_expr_reg_to_entry_parameter (frame, kind, kind_u,
678 data_src = deref_size == -1 ? parameter->value : parameter->data_value;
679 size = deref_size == -1 ? parameter->value_size : parameter->data_value_size;
681 /* DEREF_SIZE size is not verified here. */
682 if (data_src == NULL)
683 throw_error (NO_ENTRY_VALUE_ERROR,
684 _("Cannot resolve DW_AT_call_data_value"));
686 scoped_restore save_frame = make_scoped_restore (&this->frame,
688 scoped_restore save_per_cu = make_scoped_restore (&this->per_cu,
690 scoped_restore save_obj_addr = make_scoped_restore (&this->obj_address,
693 scoped_restore save_arch = make_scoped_restore (&this->gdbarch);
695 = get_objfile_arch (dwarf2_per_cu_objfile (per_cu));
696 scoped_restore save_addr_size = make_scoped_restore (&this->addr_size);
697 this->addr_size = dwarf2_per_cu_addr_size (per_cu);
698 scoped_restore save_offset = make_scoped_restore (&this->offset);
699 this->offset = dwarf2_per_cu_text_offset (per_cu);
701 this->eval (data_src, size);
704 /* Using the frame specified in BATON, find the location expression
705 describing the frame base. Return a pointer to it in START and
706 its length in LENGTH. */
707 void get_frame_base (const gdb_byte **start, size_t * length) override
709 /* FIXME: cagney/2003-03-26: This code should be using
710 get_frame_base_address(), and then implement a dwarf2 specific
712 struct symbol *framefunc;
713 const struct block *bl = get_frame_block (frame, NULL);
716 error (_("frame address is not available."));
718 /* Use block_linkage_function, which returns a real (not inlined)
719 function, instead of get_frame_function, which may return an
721 framefunc = block_linkage_function (bl);
723 /* If we found a frame-relative symbol then it was certainly within
724 some function associated with a frame. If we can't find the frame,
725 something has gone wrong. */
726 gdb_assert (framefunc != NULL);
728 func_get_frame_base_dwarf_block (framefunc,
729 get_frame_address_in_block (frame),
733 /* Read memory at ADDR (length LEN) into BUF. */
735 void read_mem (gdb_byte *buf, CORE_ADDR addr, size_t len) override
737 read_memory (addr, buf, len);
740 /* Using the frame specified in BATON, return the value of register
741 REGNUM, treated as a pointer. */
742 CORE_ADDR read_addr_from_reg (int dwarf_regnum) override
744 struct gdbarch *gdbarch = get_frame_arch (frame);
745 int regnum = dwarf_reg_to_regnum_or_error (gdbarch, dwarf_regnum);
747 return address_from_register (regnum, frame);
750 /* Implement "get_reg_value" callback. */
752 struct value *get_reg_value (struct type *type, int dwarf_regnum) override
754 struct gdbarch *gdbarch = get_frame_arch (frame);
755 int regnum = dwarf_reg_to_regnum_or_error (gdbarch, dwarf_regnum);
757 return value_from_register (type, regnum, frame);
761 /* See dwarf2loc.h. */
763 unsigned int entry_values_debug = 0;
765 /* Helper to set entry_values_debug. */
768 show_entry_values_debug (struct ui_file *file, int from_tty,
769 struct cmd_list_element *c, const char *value)
771 fprintf_filtered (file,
772 _("Entry values and tail call frames debugging is %s.\n"),
776 /* Find DW_TAG_call_site's DW_AT_call_target address.
777 CALLER_FRAME (for registers) can be NULL if it is not known. This function
778 always returns valid address or it throws NO_ENTRY_VALUE_ERROR. */
781 call_site_to_target_addr (struct gdbarch *call_site_gdbarch,
782 struct call_site *call_site,
783 struct frame_info *caller_frame)
785 switch (FIELD_LOC_KIND (call_site->target))
787 case FIELD_LOC_KIND_DWARF_BLOCK:
789 struct dwarf2_locexpr_baton *dwarf_block;
791 struct type *caller_core_addr_type;
792 struct gdbarch *caller_arch;
794 dwarf_block = FIELD_DWARF_BLOCK (call_site->target);
795 if (dwarf_block == NULL)
797 struct bound_minimal_symbol msym;
799 msym = lookup_minimal_symbol_by_pc (call_site->pc - 1);
800 throw_error (NO_ENTRY_VALUE_ERROR,
801 _("DW_AT_call_target is not specified at %s in %s"),
802 paddress (call_site_gdbarch, call_site->pc),
803 (msym.minsym == NULL ? "???"
804 : MSYMBOL_PRINT_NAME (msym.minsym)));
807 if (caller_frame == NULL)
809 struct bound_minimal_symbol msym;
811 msym = lookup_minimal_symbol_by_pc (call_site->pc - 1);
812 throw_error (NO_ENTRY_VALUE_ERROR,
813 _("DW_AT_call_target DWARF block resolving "
814 "requires known frame which is currently not "
815 "available at %s in %s"),
816 paddress (call_site_gdbarch, call_site->pc),
817 (msym.minsym == NULL ? "???"
818 : MSYMBOL_PRINT_NAME (msym.minsym)));
821 caller_arch = get_frame_arch (caller_frame);
822 caller_core_addr_type = builtin_type (caller_arch)->builtin_func_ptr;
823 val = dwarf2_evaluate_loc_desc (caller_core_addr_type, caller_frame,
824 dwarf_block->data, dwarf_block->size,
825 dwarf_block->per_cu);
826 /* DW_AT_call_target is a DWARF expression, not a DWARF location. */
827 if (VALUE_LVAL (val) == lval_memory)
828 return value_address (val);
830 return value_as_address (val);
833 case FIELD_LOC_KIND_PHYSNAME:
835 const char *physname;
836 struct bound_minimal_symbol msym;
838 physname = FIELD_STATIC_PHYSNAME (call_site->target);
840 /* Handle both the mangled and demangled PHYSNAME. */
841 msym = lookup_minimal_symbol (physname, NULL, NULL);
842 if (msym.minsym == NULL)
844 msym = lookup_minimal_symbol_by_pc (call_site->pc - 1);
845 throw_error (NO_ENTRY_VALUE_ERROR,
846 _("Cannot find function \"%s\" for a call site target "
848 physname, paddress (call_site_gdbarch, call_site->pc),
849 (msym.minsym == NULL ? "???"
850 : MSYMBOL_PRINT_NAME (msym.minsym)));
853 return BMSYMBOL_VALUE_ADDRESS (msym);
856 case FIELD_LOC_KIND_PHYSADDR:
857 return FIELD_STATIC_PHYSADDR (call_site->target);
860 internal_error (__FILE__, __LINE__, _("invalid call site target kind"));
864 /* Convert function entry point exact address ADDR to the function which is
865 compliant with TAIL_CALL_LIST_COMPLETE condition. Throw
866 NO_ENTRY_VALUE_ERROR otherwise. */
868 static struct symbol *
869 func_addr_to_tail_call_list (struct gdbarch *gdbarch, CORE_ADDR addr)
871 struct symbol *sym = find_pc_function (addr);
874 if (sym == NULL || BLOCK_ENTRY_PC (SYMBOL_BLOCK_VALUE (sym)) != addr)
875 throw_error (NO_ENTRY_VALUE_ERROR,
876 _("DW_TAG_call_site resolving failed to find function "
877 "name for address %s"),
878 paddress (gdbarch, addr));
880 type = SYMBOL_TYPE (sym);
881 gdb_assert (TYPE_CODE (type) == TYPE_CODE_FUNC);
882 gdb_assert (TYPE_SPECIFIC_FIELD (type) == TYPE_SPECIFIC_FUNC);
887 /* Verify function with entry point exact address ADDR can never call itself
888 via its tail calls (incl. transitively). Throw NO_ENTRY_VALUE_ERROR if it
889 can call itself via tail calls.
891 If a funtion can tail call itself its entry value based parameters are
892 unreliable. There is no verification whether the value of some/all
893 parameters is unchanged through the self tail call, we expect if there is
894 a self tail call all the parameters can be modified. */
897 func_verify_no_selftailcall (struct gdbarch *gdbarch, CORE_ADDR verify_addr)
901 /* The verification is completely unordered. Track here function addresses
902 which still need to be iterated. */
903 std::vector<CORE_ADDR> todo;
905 /* Track here CORE_ADDRs which were already visited. */
906 std::unordered_set<CORE_ADDR> addr_hash;
908 todo.push_back (verify_addr);
909 while (!todo.empty ())
911 struct symbol *func_sym;
912 struct call_site *call_site;
917 func_sym = func_addr_to_tail_call_list (gdbarch, addr);
919 for (call_site = TYPE_TAIL_CALL_LIST (SYMBOL_TYPE (func_sym));
920 call_site; call_site = call_site->tail_call_next)
922 CORE_ADDR target_addr;
924 /* CALLER_FRAME with registers is not available for tail-call jumped
926 target_addr = call_site_to_target_addr (gdbarch, call_site, NULL);
928 if (target_addr == verify_addr)
930 struct bound_minimal_symbol msym;
932 msym = lookup_minimal_symbol_by_pc (verify_addr);
933 throw_error (NO_ENTRY_VALUE_ERROR,
934 _("DW_OP_entry_value resolving has found "
935 "function \"%s\" at %s can call itself via tail "
937 (msym.minsym == NULL ? "???"
938 : MSYMBOL_PRINT_NAME (msym.minsym)),
939 paddress (gdbarch, verify_addr));
942 if (addr_hash.insert (target_addr).second)
943 todo.push_back (target_addr);
948 /* Print user readable form of CALL_SITE->PC to gdb_stdlog. Used only for
949 ENTRY_VALUES_DEBUG. */
952 tailcall_dump (struct gdbarch *gdbarch, const struct call_site *call_site)
954 CORE_ADDR addr = call_site->pc;
955 struct bound_minimal_symbol msym = lookup_minimal_symbol_by_pc (addr - 1);
957 fprintf_unfiltered (gdb_stdlog, " %s(%s)", paddress (gdbarch, addr),
958 (msym.minsym == NULL ? "???"
959 : MSYMBOL_PRINT_NAME (msym.minsym)));
963 /* Intersect RESULTP with CHAIN to keep RESULTP unambiguous, keep in RESULTP
964 only top callers and bottom callees which are present in both. GDBARCH is
965 used only for ENTRY_VALUES_DEBUG. RESULTP is NULL after return if there are
966 no remaining possibilities to provide unambiguous non-trivial result.
967 RESULTP should point to NULL on the first (initialization) call. Caller is
968 responsible for xfree of any RESULTP data. */
971 chain_candidate (struct gdbarch *gdbarch,
972 gdb::unique_xmalloc_ptr<struct call_site_chain> *resultp,
973 std::vector<struct call_site *> *chain)
975 long length = chain->size ();
976 int callers, callees, idx;
978 if (*resultp == NULL)
980 /* Create the initial chain containing all the passed PCs. */
982 struct call_site_chain *result
983 = ((struct call_site_chain *)
984 xmalloc (sizeof (*result)
985 + sizeof (*result->call_site) * (length - 1)));
986 result->length = length;
987 result->callers = result->callees = length;
988 if (!chain->empty ())
989 memcpy (result->call_site, chain->data (),
990 sizeof (*result->call_site) * length);
991 resultp->reset (result);
993 if (entry_values_debug)
995 fprintf_unfiltered (gdb_stdlog, "tailcall: initial:");
996 for (idx = 0; idx < length; idx++)
997 tailcall_dump (gdbarch, result->call_site[idx]);
998 fputc_unfiltered ('\n', gdb_stdlog);
1004 if (entry_values_debug)
1006 fprintf_unfiltered (gdb_stdlog, "tailcall: compare:");
1007 for (idx = 0; idx < length; idx++)
1008 tailcall_dump (gdbarch, chain->at (idx));
1009 fputc_unfiltered ('\n', gdb_stdlog);
1012 /* Intersect callers. */
1014 callers = std::min ((long) (*resultp)->callers, length);
1015 for (idx = 0; idx < callers; idx++)
1016 if ((*resultp)->call_site[idx] != chain->at (idx))
1018 (*resultp)->callers = idx;
1022 /* Intersect callees. */
1024 callees = std::min ((long) (*resultp)->callees, length);
1025 for (idx = 0; idx < callees; idx++)
1026 if ((*resultp)->call_site[(*resultp)->length - 1 - idx]
1027 != chain->at (length - 1 - idx))
1029 (*resultp)->callees = idx;
1033 if (entry_values_debug)
1035 fprintf_unfiltered (gdb_stdlog, "tailcall: reduced:");
1036 for (idx = 0; idx < (*resultp)->callers; idx++)
1037 tailcall_dump (gdbarch, (*resultp)->call_site[idx]);
1038 fputs_unfiltered (" |", gdb_stdlog);
1039 for (idx = 0; idx < (*resultp)->callees; idx++)
1040 tailcall_dump (gdbarch,
1041 (*resultp)->call_site[(*resultp)->length
1042 - (*resultp)->callees + idx]);
1043 fputc_unfiltered ('\n', gdb_stdlog);
1046 if ((*resultp)->callers == 0 && (*resultp)->callees == 0)
1048 /* There are no common callers or callees. It could be also a direct
1049 call (which has length 0) with ambiguous possibility of an indirect
1050 call - CALLERS == CALLEES == 0 is valid during the first allocation
1051 but any subsequence processing of such entry means ambiguity. */
1052 resultp->reset (NULL);
1056 /* See call_site_find_chain_1 why there is no way to reach the bottom callee
1057 PC again. In such case there must be two different code paths to reach
1058 it. CALLERS + CALLEES equal to LENGTH in the case of self tail-call. */
1059 gdb_assert ((*resultp)->callers + (*resultp)->callees <= (*resultp)->length);
1062 /* Create and return call_site_chain for CALLER_PC and CALLEE_PC. All the
1063 assumed frames between them use GDBARCH. Use depth first search so we can
1064 keep single CHAIN of call_site's back to CALLER_PC. Function recursion
1065 would have needless GDB stack overhead. Caller is responsible for xfree of
1066 the returned result. Any unreliability results in thrown
1067 NO_ENTRY_VALUE_ERROR. */
1069 static struct call_site_chain *
1070 call_site_find_chain_1 (struct gdbarch *gdbarch, CORE_ADDR caller_pc,
1071 CORE_ADDR callee_pc)
1073 CORE_ADDR save_callee_pc = callee_pc;
1074 gdb::unique_xmalloc_ptr<struct call_site_chain> retval;
1075 struct call_site *call_site;
1077 /* CHAIN contains only the intermediate CALL_SITEs. Neither CALLER_PC's
1078 call_site nor any possible call_site at CALLEE_PC's function is there.
1079 Any CALL_SITE in CHAIN will be iterated to its siblings - via
1080 TAIL_CALL_NEXT. This is inappropriate for CALLER_PC's call_site. */
1081 std::vector<struct call_site *> chain;
1083 /* We are not interested in the specific PC inside the callee function. */
1084 callee_pc = get_pc_function_start (callee_pc);
1086 throw_error (NO_ENTRY_VALUE_ERROR, _("Unable to find function for PC %s"),
1087 paddress (gdbarch, save_callee_pc));
1089 /* Mark CALL_SITEs so we do not visit the same ones twice. */
1090 std::unordered_set<CORE_ADDR> addr_hash;
1092 /* Do not push CALL_SITE to CHAIN. Push there only the first tail call site
1093 at the target's function. All the possible tail call sites in the
1094 target's function will get iterated as already pushed into CHAIN via their
1096 call_site = call_site_for_pc (gdbarch, caller_pc);
1100 CORE_ADDR target_func_addr;
1101 struct call_site *target_call_site;
1103 /* CALLER_FRAME with registers is not available for tail-call jumped
1105 target_func_addr = call_site_to_target_addr (gdbarch, call_site, NULL);
1107 if (target_func_addr == callee_pc)
1109 chain_candidate (gdbarch, &retval, &chain);
1113 /* There is no way to reach CALLEE_PC again as we would prevent
1114 entering it twice as being already marked in ADDR_HASH. */
1115 target_call_site = NULL;
1119 struct symbol *target_func;
1121 target_func = func_addr_to_tail_call_list (gdbarch, target_func_addr);
1122 target_call_site = TYPE_TAIL_CALL_LIST (SYMBOL_TYPE (target_func));
1127 /* Attempt to visit TARGET_CALL_SITE. */
1129 if (target_call_site)
1131 if (addr_hash.insert (target_call_site->pc).second)
1133 /* Successfully entered TARGET_CALL_SITE. */
1135 chain.push_back (target_call_site);
1140 /* Backtrack (without revisiting the originating call_site). Try the
1141 callers's sibling; if there isn't any try the callers's callers's
1144 target_call_site = NULL;
1145 while (!chain.empty ())
1147 call_site = chain.back ();
1150 size_t removed = addr_hash.erase (call_site->pc);
1151 gdb_assert (removed == 1);
1153 target_call_site = call_site->tail_call_next;
1154 if (target_call_site)
1158 while (target_call_site);
1163 call_site = chain.back ();
1168 struct bound_minimal_symbol msym_caller, msym_callee;
1170 msym_caller = lookup_minimal_symbol_by_pc (caller_pc);
1171 msym_callee = lookup_minimal_symbol_by_pc (callee_pc);
1172 throw_error (NO_ENTRY_VALUE_ERROR,
1173 _("There are no unambiguously determinable intermediate "
1174 "callers or callees between caller function \"%s\" at %s "
1175 "and callee function \"%s\" at %s"),
1176 (msym_caller.minsym == NULL
1177 ? "???" : MSYMBOL_PRINT_NAME (msym_caller.minsym)),
1178 paddress (gdbarch, caller_pc),
1179 (msym_callee.minsym == NULL
1180 ? "???" : MSYMBOL_PRINT_NAME (msym_callee.minsym)),
1181 paddress (gdbarch, callee_pc));
1184 return retval.release ();
1187 /* Create and return call_site_chain for CALLER_PC and CALLEE_PC. All the
1188 assumed frames between them use GDBARCH. If valid call_site_chain cannot be
1189 constructed return NULL. Caller is responsible for xfree of the returned
1192 struct call_site_chain *
1193 call_site_find_chain (struct gdbarch *gdbarch, CORE_ADDR caller_pc,
1194 CORE_ADDR callee_pc)
1196 struct call_site_chain *retval = NULL;
1200 retval = call_site_find_chain_1 (gdbarch, caller_pc, callee_pc);
1202 CATCH (e, RETURN_MASK_ERROR)
1204 if (e.error == NO_ENTRY_VALUE_ERROR)
1206 if (entry_values_debug)
1207 exception_print (gdb_stdout, e);
1212 throw_exception (e);
1219 /* Return 1 if KIND and KIND_U match PARAMETER. Return 0 otherwise. */
1222 call_site_parameter_matches (struct call_site_parameter *parameter,
1223 enum call_site_parameter_kind kind,
1224 union call_site_parameter_u kind_u)
1226 if (kind == parameter->kind)
1229 case CALL_SITE_PARAMETER_DWARF_REG:
1230 return kind_u.dwarf_reg == parameter->u.dwarf_reg;
1231 case CALL_SITE_PARAMETER_FB_OFFSET:
1232 return kind_u.fb_offset == parameter->u.fb_offset;
1233 case CALL_SITE_PARAMETER_PARAM_OFFSET:
1234 return kind_u.param_cu_off == parameter->u.param_cu_off;
1239 /* Fetch call_site_parameter from caller matching KIND and KIND_U.
1240 FRAME is for callee.
1242 Function always returns non-NULL, it throws NO_ENTRY_VALUE_ERROR
1245 static struct call_site_parameter *
1246 dwarf_expr_reg_to_entry_parameter (struct frame_info *frame,
1247 enum call_site_parameter_kind kind,
1248 union call_site_parameter_u kind_u,
1249 struct dwarf2_per_cu_data **per_cu_return)
1251 CORE_ADDR func_addr, caller_pc;
1252 struct gdbarch *gdbarch;
1253 struct frame_info *caller_frame;
1254 struct call_site *call_site;
1256 /* Initialize it just to avoid a GCC false warning. */
1257 struct call_site_parameter *parameter = NULL;
1258 CORE_ADDR target_addr;
1260 while (get_frame_type (frame) == INLINE_FRAME)
1262 frame = get_prev_frame (frame);
1263 gdb_assert (frame != NULL);
1266 func_addr = get_frame_func (frame);
1267 gdbarch = get_frame_arch (frame);
1268 caller_frame = get_prev_frame (frame);
1269 if (gdbarch != frame_unwind_arch (frame))
1271 struct bound_minimal_symbol msym
1272 = lookup_minimal_symbol_by_pc (func_addr);
1273 struct gdbarch *caller_gdbarch = frame_unwind_arch (frame);
1275 throw_error (NO_ENTRY_VALUE_ERROR,
1276 _("DW_OP_entry_value resolving callee gdbarch %s "
1277 "(of %s (%s)) does not match caller gdbarch %s"),
1278 gdbarch_bfd_arch_info (gdbarch)->printable_name,
1279 paddress (gdbarch, func_addr),
1280 (msym.minsym == NULL ? "???"
1281 : MSYMBOL_PRINT_NAME (msym.minsym)),
1282 gdbarch_bfd_arch_info (caller_gdbarch)->printable_name);
1285 if (caller_frame == NULL)
1287 struct bound_minimal_symbol msym
1288 = lookup_minimal_symbol_by_pc (func_addr);
1290 throw_error (NO_ENTRY_VALUE_ERROR, _("DW_OP_entry_value resolving "
1291 "requires caller of %s (%s)"),
1292 paddress (gdbarch, func_addr),
1293 (msym.minsym == NULL ? "???"
1294 : MSYMBOL_PRINT_NAME (msym.minsym)));
1296 caller_pc = get_frame_pc (caller_frame);
1297 call_site = call_site_for_pc (gdbarch, caller_pc);
1299 target_addr = call_site_to_target_addr (gdbarch, call_site, caller_frame);
1300 if (target_addr != func_addr)
1302 struct minimal_symbol *target_msym, *func_msym;
1304 target_msym = lookup_minimal_symbol_by_pc (target_addr).minsym;
1305 func_msym = lookup_minimal_symbol_by_pc (func_addr).minsym;
1306 throw_error (NO_ENTRY_VALUE_ERROR,
1307 _("DW_OP_entry_value resolving expects callee %s at %s "
1308 "but the called frame is for %s at %s"),
1309 (target_msym == NULL ? "???"
1310 : MSYMBOL_PRINT_NAME (target_msym)),
1311 paddress (gdbarch, target_addr),
1312 func_msym == NULL ? "???" : MSYMBOL_PRINT_NAME (func_msym),
1313 paddress (gdbarch, func_addr));
1316 /* No entry value based parameters would be reliable if this function can
1317 call itself via tail calls. */
1318 func_verify_no_selftailcall (gdbarch, func_addr);
1320 for (iparams = 0; iparams < call_site->parameter_count; iparams++)
1322 parameter = &call_site->parameter[iparams];
1323 if (call_site_parameter_matches (parameter, kind, kind_u))
1326 if (iparams == call_site->parameter_count)
1328 struct minimal_symbol *msym
1329 = lookup_minimal_symbol_by_pc (caller_pc).minsym;
1331 /* DW_TAG_call_site_parameter will be missing just if GCC could not
1332 determine its value. */
1333 throw_error (NO_ENTRY_VALUE_ERROR, _("Cannot find matching parameter "
1334 "at DW_TAG_call_site %s at %s"),
1335 paddress (gdbarch, caller_pc),
1336 msym == NULL ? "???" : MSYMBOL_PRINT_NAME (msym));
1339 *per_cu_return = call_site->per_cu;
1343 /* Return value for PARAMETER matching DEREF_SIZE. If DEREF_SIZE is -1, return
1344 the normal DW_AT_call_value block. Otherwise return the
1345 DW_AT_call_data_value (dereferenced) block.
1347 TYPE and CALLER_FRAME specify how to evaluate the DWARF block into returned
1350 Function always returns non-NULL, non-optimized out value. It throws
1351 NO_ENTRY_VALUE_ERROR if it cannot resolve the value for any reason. */
1353 static struct value *
1354 dwarf_entry_parameter_to_value (struct call_site_parameter *parameter,
1355 CORE_ADDR deref_size, struct type *type,
1356 struct frame_info *caller_frame,
1357 struct dwarf2_per_cu_data *per_cu)
1359 const gdb_byte *data_src;
1363 data_src = deref_size == -1 ? parameter->value : parameter->data_value;
1364 size = deref_size == -1 ? parameter->value_size : parameter->data_value_size;
1366 /* DEREF_SIZE size is not verified here. */
1367 if (data_src == NULL)
1368 throw_error (NO_ENTRY_VALUE_ERROR,
1369 _("Cannot resolve DW_AT_call_data_value"));
1371 /* DW_AT_call_value is a DWARF expression, not a DWARF
1372 location. Postprocessing of DWARF_VALUE_MEMORY would lose the type from
1374 data = (gdb_byte *) alloca (size + 1);
1375 memcpy (data, data_src, size);
1376 data[size] = DW_OP_stack_value;
1378 return dwarf2_evaluate_loc_desc (type, caller_frame, data, size + 1, per_cu);
1381 /* VALUE must be of type lval_computed with entry_data_value_funcs. Perform
1382 the indirect method on it, that is use its stored target value, the sole
1383 purpose of entry_data_value_funcs.. */
1385 static struct value *
1386 entry_data_value_coerce_ref (const struct value *value)
1388 struct type *checked_type = check_typedef (value_type (value));
1389 struct value *target_val;
1391 if (!TYPE_IS_REFERENCE (checked_type))
1394 target_val = (struct value *) value_computed_closure (value);
1395 value_incref (target_val);
1399 /* Implement copy_closure. */
1402 entry_data_value_copy_closure (const struct value *v)
1404 struct value *target_val = (struct value *) value_computed_closure (v);
1406 value_incref (target_val);
1410 /* Implement free_closure. */
1413 entry_data_value_free_closure (struct value *v)
1415 struct value *target_val = (struct value *) value_computed_closure (v);
1417 value_decref (target_val);
1420 /* Vector for methods for an entry value reference where the referenced value
1421 is stored in the caller. On the first dereference use
1422 DW_AT_call_data_value in the caller. */
1424 static const struct lval_funcs entry_data_value_funcs =
1428 NULL, /* indirect */
1429 entry_data_value_coerce_ref,
1430 NULL, /* check_synthetic_pointer */
1431 entry_data_value_copy_closure,
1432 entry_data_value_free_closure
1435 /* Read parameter of TYPE at (callee) FRAME's function entry. KIND and KIND_U
1436 are used to match DW_AT_location at the caller's
1437 DW_TAG_call_site_parameter.
1439 Function always returns non-NULL value. It throws NO_ENTRY_VALUE_ERROR if it
1440 cannot resolve the parameter for any reason. */
1442 static struct value *
1443 value_of_dwarf_reg_entry (struct type *type, struct frame_info *frame,
1444 enum call_site_parameter_kind kind,
1445 union call_site_parameter_u kind_u)
1447 struct type *checked_type = check_typedef (type);
1448 struct type *target_type = TYPE_TARGET_TYPE (checked_type);
1449 struct frame_info *caller_frame = get_prev_frame (frame);
1450 struct value *outer_val, *target_val, *val;
1451 struct call_site_parameter *parameter;
1452 struct dwarf2_per_cu_data *caller_per_cu;
1454 parameter = dwarf_expr_reg_to_entry_parameter (frame, kind, kind_u,
1457 outer_val = dwarf_entry_parameter_to_value (parameter, -1 /* deref_size */,
1461 /* Check if DW_AT_call_data_value cannot be used. If it should be
1462 used and it is not available do not fall back to OUTER_VAL - dereferencing
1463 TYPE_CODE_REF with non-entry data value would give current value - not the
1466 if (!TYPE_IS_REFERENCE (checked_type)
1467 || TYPE_TARGET_TYPE (checked_type) == NULL)
1470 target_val = dwarf_entry_parameter_to_value (parameter,
1471 TYPE_LENGTH (target_type),
1472 target_type, caller_frame,
1475 release_value (target_val).release ();
1476 val = allocate_computed_value (type, &entry_data_value_funcs,
1477 target_val /* closure */);
1479 /* Copy the referencing pointer to the new computed value. */
1480 memcpy (value_contents_raw (val), value_contents_raw (outer_val),
1481 TYPE_LENGTH (checked_type));
1482 set_value_lazy (val, 0);
1487 /* Read parameter of TYPE at (callee) FRAME's function entry. DATA and
1488 SIZE are DWARF block used to match DW_AT_location at the caller's
1489 DW_TAG_call_site_parameter.
1491 Function always returns non-NULL value. It throws NO_ENTRY_VALUE_ERROR if it
1492 cannot resolve the parameter for any reason. */
1494 static struct value *
1495 value_of_dwarf_block_entry (struct type *type, struct frame_info *frame,
1496 const gdb_byte *block, size_t block_len)
1498 union call_site_parameter_u kind_u;
1500 kind_u.dwarf_reg = dwarf_block_to_dwarf_reg (block, block + block_len);
1501 if (kind_u.dwarf_reg != -1)
1502 return value_of_dwarf_reg_entry (type, frame, CALL_SITE_PARAMETER_DWARF_REG,
1505 if (dwarf_block_to_fb_offset (block, block + block_len, &kind_u.fb_offset))
1506 return value_of_dwarf_reg_entry (type, frame, CALL_SITE_PARAMETER_FB_OFFSET,
1509 /* This can normally happen - throw NO_ENTRY_VALUE_ERROR to get the message
1510 suppressed during normal operation. The expression can be arbitrary if
1511 there is no caller-callee entry value binding expected. */
1512 throw_error (NO_ENTRY_VALUE_ERROR,
1513 _("DWARF-2 expression error: DW_OP_entry_value is supported "
1514 "only for single DW_OP_reg* or for DW_OP_fbreg(*)"));
1517 struct piece_closure
1519 /* Reference count. */
1522 /* The CU from which this closure's expression came. */
1523 struct dwarf2_per_cu_data *per_cu = NULL;
1525 /* The pieces describing this variable. */
1526 std::vector<dwarf_expr_piece> pieces;
1528 /* Frame ID of frame to which a register value is relative, used
1529 only by DWARF_VALUE_REGISTER. */
1530 struct frame_id frame_id;
1533 /* Allocate a closure for a value formed from separately-described
1536 static struct piece_closure *
1537 allocate_piece_closure (struct dwarf2_per_cu_data *per_cu,
1538 std::vector<dwarf_expr_piece> &&pieces,
1539 struct frame_info *frame)
1541 struct piece_closure *c = new piece_closure;
1545 c->pieces = std::move (pieces);
1547 c->frame_id = null_frame_id;
1549 c->frame_id = get_frame_id (frame);
1551 for (dwarf_expr_piece &piece : c->pieces)
1552 if (piece.location == DWARF_VALUE_STACK)
1553 value_incref (piece.v.value);
1558 /* Copy NBITS bits from SOURCE to DEST starting at the given bit
1559 offsets. Use the bit order as specified by BITS_BIG_ENDIAN.
1560 Source and destination buffers must not overlap. */
1563 copy_bitwise (gdb_byte *dest, ULONGEST dest_offset,
1564 const gdb_byte *source, ULONGEST source_offset,
1565 ULONGEST nbits, int bits_big_endian)
1567 unsigned int buf, avail;
1572 if (bits_big_endian)
1574 /* Start from the end, then work backwards. */
1575 dest_offset += nbits - 1;
1576 dest += dest_offset / 8;
1577 dest_offset = 7 - dest_offset % 8;
1578 source_offset += nbits - 1;
1579 source += source_offset / 8;
1580 source_offset = 7 - source_offset % 8;
1584 dest += dest_offset / 8;
1586 source += source_offset / 8;
1590 /* Fill BUF with DEST_OFFSET bits from the destination and 8 -
1591 SOURCE_OFFSET bits from the source. */
1592 buf = *(bits_big_endian ? source-- : source++) >> source_offset;
1593 buf <<= dest_offset;
1594 buf |= *dest & ((1 << dest_offset) - 1);
1596 /* NBITS: bits yet to be written; AVAIL: BUF's fill level. */
1597 nbits += dest_offset;
1598 avail = dest_offset + 8 - source_offset;
1600 /* Flush 8 bits from BUF, if appropriate. */
1601 if (nbits >= 8 && avail >= 8)
1603 *(bits_big_endian ? dest-- : dest++) = buf;
1609 /* Copy the middle part. */
1612 size_t len = nbits / 8;
1614 /* Use a faster method for byte-aligned copies. */
1617 if (bits_big_endian)
1621 memcpy (dest + 1, source + 1, len);
1625 memcpy (dest, source, len);
1634 buf |= *(bits_big_endian ? source-- : source++) << avail;
1635 *(bits_big_endian ? dest-- : dest++) = buf;
1642 /* Write the last byte. */
1646 buf |= *source << avail;
1648 buf &= (1 << nbits) - 1;
1649 *dest = (*dest & (~0 << nbits)) | buf;
1655 namespace selftests {
1657 /* Helper function for the unit test of copy_bitwise. Convert NBITS bits
1658 out of BITS, starting at OFFS, to the respective '0'/'1'-string. MSB0
1659 specifies whether to assume big endian bit numbering. Store the
1660 resulting (not null-terminated) string at STR. */
1663 bits_to_str (char *str, const gdb_byte *bits, ULONGEST offs,
1664 ULONGEST nbits, int msb0)
1669 for (i = offs / 8, j = offs % 8; nbits; i++, j = 0)
1671 unsigned int ch = bits[i];
1672 for (; j < 8 && nbits; j++, nbits--)
1673 *str++ = (ch & (msb0 ? (1 << (7 - j)) : (1 << j))) ? '1' : '0';
1677 /* Check one invocation of copy_bitwise with the given parameters. */
1680 check_copy_bitwise (const gdb_byte *dest, unsigned int dest_offset,
1681 const gdb_byte *source, unsigned int source_offset,
1682 unsigned int nbits, int msb0)
1684 size_t len = align_up (dest_offset + nbits, 8);
1685 char *expected = (char *) alloca (len + 1);
1686 char *actual = (char *) alloca (len + 1);
1687 gdb_byte *buf = (gdb_byte *) alloca (len / 8);
1689 /* Compose a '0'/'1'-string that represents the expected result of
1691 Bits from [0, DEST_OFFSET) are filled from DEST.
1692 Bits from [DEST_OFFSET, DEST_OFFSET + NBITS) are filled from SOURCE.
1693 Bits from [DEST_OFFSET + NBITS, LEN) are filled from DEST.
1702 We should end up with:
1704 DDDDSSDD (D=dest, S=source)
1706 bits_to_str (expected, dest, 0, len, msb0);
1707 bits_to_str (expected + dest_offset, source, source_offset, nbits, msb0);
1709 /* Fill BUF with data from DEST, apply copy_bitwise, and convert the
1710 result to a '0'/'1'-string. */
1711 memcpy (buf, dest, len / 8);
1712 copy_bitwise (buf, dest_offset, source, source_offset, nbits, msb0);
1713 bits_to_str (actual, buf, 0, len, msb0);
1715 /* Compare the resulting strings. */
1716 expected[len] = actual[len] = '\0';
1717 if (strcmp (expected, actual) != 0)
1718 error (_("copy_bitwise %s != %s (%u+%u -> %u)"),
1719 expected, actual, source_offset, nbits, dest_offset);
1722 /* Unit test for copy_bitwise. */
1725 copy_bitwise_tests (void)
1727 /* Data to be used as both source and destination buffers. The two
1728 arrays below represent the lsb0- and msb0- encoded versions of the
1729 following bit string, respectively:
1730 00000000 00011111 11111111 01001000 10100101 11110010
1731 This pattern is chosen such that it contains:
1732 - constant 0- and 1- chunks of more than a full byte;
1733 - 0/1- and 1/0 transitions on all bit positions within a byte;
1734 - several sufficiently asymmetric bytes.
1736 static const gdb_byte data_lsb0[] = {
1737 0x00, 0xf8, 0xff, 0x12, 0xa5, 0x4f
1739 static const gdb_byte data_msb0[] = {
1740 0x00, 0x1f, 0xff, 0x48, 0xa5, 0xf2
1743 constexpr size_t data_nbits = 8 * sizeof (data_lsb0);
1744 constexpr unsigned max_nbits = 24;
1746 /* Try all combinations of:
1747 lsb0/msb0 bit order (using the respective data array)
1748 X [0, MAX_NBITS] copy bit width
1749 X feasible source offsets for the given copy bit width
1750 X feasible destination offsets
1752 for (int msb0 = 0; msb0 < 2; msb0++)
1754 const gdb_byte *data = msb0 ? data_msb0 : data_lsb0;
1756 for (unsigned int nbits = 1; nbits <= max_nbits; nbits++)
1758 const unsigned int max_offset = data_nbits - nbits;
1760 for (unsigned source_offset = 0;
1761 source_offset <= max_offset;
1764 for (unsigned dest_offset = 0;
1765 dest_offset <= max_offset;
1768 check_copy_bitwise (data + dest_offset / 8,
1770 data + source_offset / 8,
1777 /* Special cases: copy all, copy nothing. */
1778 check_copy_bitwise (data_lsb0, 0, data_msb0, 0, data_nbits, msb0);
1779 check_copy_bitwise (data_msb0, 0, data_lsb0, 0, data_nbits, msb0);
1780 check_copy_bitwise (data, data_nbits - 7, data, 9, 0, msb0);
1784 } /* namespace selftests */
1786 #endif /* GDB_SELF_TEST */
1788 /* Return the number of bytes overlapping a contiguous chunk of N_BITS
1789 bits whose first bit is located at bit offset START. */
1792 bits_to_bytes (ULONGEST start, ULONGEST n_bits)
1794 return (start % 8 + n_bits + 7) / 8;
1797 /* Read or write a pieced value V. If FROM != NULL, operate in "write
1798 mode": copy FROM into the pieces comprising V. If FROM == NULL,
1799 operate in "read mode": fetch the contents of the (lazy) value V by
1800 composing it from its pieces. */
1803 rw_pieced_value (struct value *v, struct value *from)
1806 LONGEST offset = 0, max_offset;
1807 ULONGEST bits_to_skip;
1808 gdb_byte *v_contents;
1809 const gdb_byte *from_contents;
1810 struct piece_closure *c
1811 = (struct piece_closure *) value_computed_closure (v);
1812 gdb::byte_vector buffer;
1814 = gdbarch_bits_big_endian (get_type_arch (value_type (v)));
1818 from_contents = value_contents (from);
1823 if (value_type (v) != value_enclosing_type (v))
1824 internal_error (__FILE__, __LINE__,
1825 _("Should not be able to create a lazy value with "
1826 "an enclosing type"));
1827 v_contents = value_contents_raw (v);
1828 from_contents = NULL;
1831 bits_to_skip = 8 * value_offset (v);
1832 if (value_bitsize (v))
1834 bits_to_skip += (8 * value_offset (value_parent (v))
1835 + value_bitpos (v));
1837 && (gdbarch_byte_order (get_type_arch (value_type (from)))
1840 /* Use the least significant bits of FROM. */
1841 max_offset = 8 * TYPE_LENGTH (value_type (from));
1842 offset = max_offset - value_bitsize (v);
1845 max_offset = value_bitsize (v);
1848 max_offset = 8 * TYPE_LENGTH (value_type (v));
1850 /* Advance to the first non-skipped piece. */
1851 for (i = 0; i < c->pieces.size () && bits_to_skip >= c->pieces[i].size; i++)
1852 bits_to_skip -= c->pieces[i].size;
1854 for (; i < c->pieces.size () && offset < max_offset; i++)
1856 struct dwarf_expr_piece *p = &c->pieces[i];
1857 size_t this_size_bits, this_size;
1859 this_size_bits = p->size - bits_to_skip;
1860 if (this_size_bits > max_offset - offset)
1861 this_size_bits = max_offset - offset;
1863 switch (p->location)
1865 case DWARF_VALUE_REGISTER:
1867 struct frame_info *frame = frame_find_by_id (c->frame_id);
1868 struct gdbarch *arch = get_frame_arch (frame);
1869 int gdb_regnum = dwarf_reg_to_regnum_or_error (arch, p->v.regno);
1870 ULONGEST reg_bits = 8 * register_size (arch, gdb_regnum);
1873 if (gdbarch_byte_order (arch) == BFD_ENDIAN_BIG
1874 && p->offset + p->size < reg_bits)
1876 /* Big-endian, and we want less than full size. */
1877 bits_to_skip += reg_bits - (p->offset + p->size);
1880 bits_to_skip += p->offset;
1882 this_size = bits_to_bytes (bits_to_skip, this_size_bits);
1883 buffer.resize (this_size);
1888 if (!get_frame_register_bytes (frame, gdb_regnum,
1890 this_size, buffer.data (),
1894 mark_value_bits_optimized_out (v, offset,
1897 mark_value_bits_unavailable (v, offset,
1902 copy_bitwise (v_contents, offset,
1903 buffer.data (), bits_to_skip % 8,
1904 this_size_bits, bits_big_endian);
1909 if (bits_to_skip % 8 != 0 || this_size_bits % 8 != 0)
1911 /* Data is copied non-byte-aligned into the register.
1912 Need some bits from original register value. */
1913 get_frame_register_bytes (frame, gdb_regnum,
1915 this_size, buffer.data (),
1918 throw_error (OPTIMIZED_OUT_ERROR,
1919 _("Can't do read-modify-write to "
1920 "update bitfield; containing word "
1921 "has been optimized out"));
1923 throw_error (NOT_AVAILABLE_ERROR,
1924 _("Can't do read-modify-write to "
1925 "update bitfield; containing word "
1929 copy_bitwise (buffer.data (), bits_to_skip % 8,
1930 from_contents, offset,
1931 this_size_bits, bits_big_endian);
1932 put_frame_register_bytes (frame, gdb_regnum,
1934 this_size, buffer.data ());
1939 case DWARF_VALUE_MEMORY:
1941 bits_to_skip += p->offset;
1943 CORE_ADDR start_addr = p->v.mem.addr + bits_to_skip / 8;
1945 if (bits_to_skip % 8 == 0 && this_size_bits % 8 == 0
1948 /* Everything is byte-aligned; no buffer needed. */
1950 write_memory_with_notification (start_addr,
1953 this_size_bits / 8);
1955 read_value_memory (v, offset,
1956 p->v.mem.in_stack_memory,
1957 p->v.mem.addr + bits_to_skip / 8,
1958 v_contents + offset / 8,
1959 this_size_bits / 8);
1963 this_size = bits_to_bytes (bits_to_skip, this_size_bits);
1964 buffer.resize (this_size);
1969 read_value_memory (v, offset,
1970 p->v.mem.in_stack_memory,
1971 p->v.mem.addr + bits_to_skip / 8,
1972 buffer.data (), this_size);
1973 copy_bitwise (v_contents, offset,
1974 buffer.data (), bits_to_skip % 8,
1975 this_size_bits, bits_big_endian);
1980 if (bits_to_skip % 8 != 0 || this_size_bits % 8 != 0)
1984 /* Perform a single read for small sizes. */
1985 read_memory (start_addr, buffer.data (),
1990 /* Only the first and last bytes can possibly have
1992 read_memory (start_addr, buffer.data (), 1);
1993 read_memory (start_addr + this_size - 1,
1994 &buffer[this_size - 1], 1);
1998 copy_bitwise (buffer.data (), bits_to_skip % 8,
1999 from_contents, offset,
2000 this_size_bits, bits_big_endian);
2001 write_memory_with_notification (start_addr,
2008 case DWARF_VALUE_STACK:
2012 mark_value_bits_optimized_out (v, offset, this_size_bits);
2016 struct objfile *objfile = dwarf2_per_cu_objfile (c->per_cu);
2017 struct gdbarch *objfile_gdbarch = get_objfile_arch (objfile);
2018 ULONGEST stack_value_size_bits
2019 = 8 * TYPE_LENGTH (value_type (p->v.value));
2021 /* Use zeroes if piece reaches beyond stack value. */
2022 if (p->offset + p->size > stack_value_size_bits)
2025 /* Piece is anchored at least significant bit end. */
2026 if (gdbarch_byte_order (objfile_gdbarch) == BFD_ENDIAN_BIG)
2027 bits_to_skip += stack_value_size_bits - p->offset - p->size;
2029 bits_to_skip += p->offset;
2031 copy_bitwise (v_contents, offset,
2032 value_contents_all (p->v.value),
2034 this_size_bits, bits_big_endian);
2038 case DWARF_VALUE_LITERAL:
2042 mark_value_bits_optimized_out (v, offset, this_size_bits);
2046 ULONGEST literal_size_bits = 8 * p->v.literal.length;
2047 size_t n = this_size_bits;
2049 /* Cut off at the end of the implicit value. */
2050 bits_to_skip += p->offset;
2051 if (bits_to_skip >= literal_size_bits)
2053 if (n > literal_size_bits - bits_to_skip)
2054 n = literal_size_bits - bits_to_skip;
2056 copy_bitwise (v_contents, offset,
2057 p->v.literal.data, bits_to_skip,
2058 n, bits_big_endian);
2062 case DWARF_VALUE_IMPLICIT_POINTER:
2065 mark_value_bits_optimized_out (v, offset, this_size_bits);
2069 /* These bits show up as zeros -- but do not cause the value to
2070 be considered optimized-out. */
2073 case DWARF_VALUE_OPTIMIZED_OUT:
2074 mark_value_bits_optimized_out (v, offset, this_size_bits);
2078 internal_error (__FILE__, __LINE__, _("invalid location type"));
2081 offset += this_size_bits;
2088 read_pieced_value (struct value *v)
2090 rw_pieced_value (v, NULL);
2094 write_pieced_value (struct value *to, struct value *from)
2096 rw_pieced_value (to, from);
2099 /* An implementation of an lval_funcs method to see whether a value is
2100 a synthetic pointer. */
2103 check_pieced_synthetic_pointer (const struct value *value, LONGEST bit_offset,
2106 struct piece_closure *c
2107 = (struct piece_closure *) value_computed_closure (value);
2110 bit_offset += 8 * value_offset (value);
2111 if (value_bitsize (value))
2112 bit_offset += value_bitpos (value);
2114 for (i = 0; i < c->pieces.size () && bit_length > 0; i++)
2116 struct dwarf_expr_piece *p = &c->pieces[i];
2117 size_t this_size_bits = p->size;
2121 if (bit_offset >= this_size_bits)
2123 bit_offset -= this_size_bits;
2127 bit_length -= this_size_bits - bit_offset;
2131 bit_length -= this_size_bits;
2133 if (p->location != DWARF_VALUE_IMPLICIT_POINTER)
2140 /* A wrapper function for get_frame_address_in_block. */
2143 get_frame_address_in_block_wrapper (void *baton)
2145 return get_frame_address_in_block ((struct frame_info *) baton);
2148 /* Fetch a DW_AT_const_value through a synthetic pointer. */
2150 static struct value *
2151 fetch_const_value_from_synthetic_pointer (sect_offset die, LONGEST byte_offset,
2152 struct dwarf2_per_cu_data *per_cu,
2155 struct value *result = NULL;
2156 const gdb_byte *bytes;
2159 auto_obstack temp_obstack;
2160 bytes = dwarf2_fetch_constant_bytes (die, per_cu, &temp_obstack, &len);
2164 if (byte_offset >= 0
2165 && byte_offset + TYPE_LENGTH (TYPE_TARGET_TYPE (type)) <= len)
2167 bytes += byte_offset;
2168 result = value_from_contents (TYPE_TARGET_TYPE (type), bytes);
2171 invalid_synthetic_pointer ();
2174 result = allocate_optimized_out_value (TYPE_TARGET_TYPE (type));
2179 /* Fetch the value pointed to by a synthetic pointer. */
2181 static struct value *
2182 indirect_synthetic_pointer (sect_offset die, LONGEST byte_offset,
2183 struct dwarf2_per_cu_data *per_cu,
2184 struct frame_info *frame, struct type *type,
2185 bool resolve_abstract_p)
2187 /* Fetch the location expression of the DIE we're pointing to. */
2188 struct dwarf2_locexpr_baton baton
2189 = dwarf2_fetch_die_loc_sect_off (die, per_cu,
2190 get_frame_address_in_block_wrapper, frame,
2191 resolve_abstract_p);
2193 /* Get type of pointed-to DIE. */
2194 struct type *orig_type = dwarf2_fetch_die_type_sect_off (die, per_cu);
2195 if (orig_type == NULL)
2196 invalid_synthetic_pointer ();
2198 /* If pointed-to DIE has a DW_AT_location, evaluate it and return the
2199 resulting value. Otherwise, it may have a DW_AT_const_value instead,
2200 or it may've been optimized out. */
2201 if (baton.data != NULL)
2202 return dwarf2_evaluate_loc_desc_full (orig_type, frame, baton.data,
2203 baton.size, baton.per_cu,
2204 TYPE_TARGET_TYPE (type),
2207 return fetch_const_value_from_synthetic_pointer (die, byte_offset, per_cu,
2211 /* An implementation of an lval_funcs method to indirect through a
2212 pointer. This handles the synthetic pointer case when needed. */
2214 static struct value *
2215 indirect_pieced_value (struct value *value)
2217 struct piece_closure *c
2218 = (struct piece_closure *) value_computed_closure (value);
2220 struct frame_info *frame;
2223 struct dwarf_expr_piece *piece = NULL;
2224 LONGEST byte_offset;
2225 enum bfd_endian byte_order;
2227 type = check_typedef (value_type (value));
2228 if (TYPE_CODE (type) != TYPE_CODE_PTR)
2231 bit_length = 8 * TYPE_LENGTH (type);
2232 bit_offset = 8 * value_offset (value);
2233 if (value_bitsize (value))
2234 bit_offset += value_bitpos (value);
2236 for (i = 0; i < c->pieces.size () && bit_length > 0; i++)
2238 struct dwarf_expr_piece *p = &c->pieces[i];
2239 size_t this_size_bits = p->size;
2243 if (bit_offset >= this_size_bits)
2245 bit_offset -= this_size_bits;
2249 bit_length -= this_size_bits - bit_offset;
2253 bit_length -= this_size_bits;
2255 if (p->location != DWARF_VALUE_IMPLICIT_POINTER)
2258 if (bit_length != 0)
2259 error (_("Invalid use of DW_OP_implicit_pointer"));
2265 gdb_assert (piece != NULL);
2266 frame = get_selected_frame (_("No frame selected."));
2268 /* This is an offset requested by GDB, such as value subscripts.
2269 However, due to how synthetic pointers are implemented, this is
2270 always presented to us as a pointer type. This means we have to
2271 sign-extend it manually as appropriate. Use raw
2272 extract_signed_integer directly rather than value_as_address and
2273 sign extend afterwards on architectures that would need it
2274 (mostly everywhere except MIPS, which has signed addresses) as
2275 the later would go through gdbarch_pointer_to_address and thus
2276 return a CORE_ADDR with high bits set on architectures that
2277 encode address spaces and other things in CORE_ADDR. */
2278 byte_order = gdbarch_byte_order (get_frame_arch (frame));
2279 byte_offset = extract_signed_integer (value_contents (value),
2280 TYPE_LENGTH (type), byte_order);
2281 byte_offset += piece->v.ptr.offset;
2283 return indirect_synthetic_pointer (piece->v.ptr.die_sect_off,
2284 byte_offset, c->per_cu,
2288 /* Implementation of the coerce_ref method of lval_funcs for synthetic C++
2291 static struct value *
2292 coerce_pieced_ref (const struct value *value)
2294 struct type *type = check_typedef (value_type (value));
2296 if (value_bits_synthetic_pointer (value, value_embedded_offset (value),
2297 TARGET_CHAR_BIT * TYPE_LENGTH (type)))
2299 const struct piece_closure *closure
2300 = (struct piece_closure *) value_computed_closure (value);
2301 struct frame_info *frame
2302 = get_selected_frame (_("No frame selected."));
2304 /* gdb represents synthetic pointers as pieced values with a single
2306 gdb_assert (closure != NULL);
2307 gdb_assert (closure->pieces.size () == 1);
2309 return indirect_synthetic_pointer
2310 (closure->pieces[0].v.ptr.die_sect_off,
2311 closure->pieces[0].v.ptr.offset,
2312 closure->per_cu, frame, type);
2316 /* Else: not a synthetic reference; do nothing. */
2322 copy_pieced_value_closure (const struct value *v)
2324 struct piece_closure *c
2325 = (struct piece_closure *) value_computed_closure (v);
2332 free_pieced_value_closure (struct value *v)
2334 struct piece_closure *c
2335 = (struct piece_closure *) value_computed_closure (v);
2340 for (dwarf_expr_piece &p : c->pieces)
2341 if (p.location == DWARF_VALUE_STACK)
2342 value_decref (p.v.value);
2348 /* Functions for accessing a variable described by DW_OP_piece. */
2349 static const struct lval_funcs pieced_value_funcs = {
2352 indirect_pieced_value,
2354 check_pieced_synthetic_pointer,
2355 copy_pieced_value_closure,
2356 free_pieced_value_closure
2359 /* Evaluate a location description, starting at DATA and with length
2360 SIZE, to find the current location of variable of TYPE in the
2361 context of FRAME. If SUBOBJ_TYPE is non-NULL, return instead the
2362 location of the subobject of type SUBOBJ_TYPE at byte offset
2363 SUBOBJ_BYTE_OFFSET within the variable of type TYPE. */
2365 static struct value *
2366 dwarf2_evaluate_loc_desc_full (struct type *type, struct frame_info *frame,
2367 const gdb_byte *data, size_t size,
2368 struct dwarf2_per_cu_data *per_cu,
2369 struct type *subobj_type,
2370 LONGEST subobj_byte_offset)
2372 struct value *retval;
2373 struct objfile *objfile = dwarf2_per_cu_objfile (per_cu);
2375 if (subobj_type == NULL)
2378 subobj_byte_offset = 0;
2380 else if (subobj_byte_offset < 0)
2381 invalid_synthetic_pointer ();
2384 return allocate_optimized_out_value (subobj_type);
2386 dwarf_evaluate_loc_desc ctx;
2388 ctx.per_cu = per_cu;
2389 ctx.obj_address = 0;
2391 scoped_value_mark free_values;
2393 ctx.gdbarch = get_objfile_arch (objfile);
2394 ctx.addr_size = dwarf2_per_cu_addr_size (per_cu);
2395 ctx.ref_addr_size = dwarf2_per_cu_ref_addr_size (per_cu);
2396 ctx.offset = dwarf2_per_cu_text_offset (per_cu);
2400 ctx.eval (data, size);
2402 CATCH (ex, RETURN_MASK_ERROR)
2404 if (ex.error == NOT_AVAILABLE_ERROR)
2406 free_values.free_to_mark ();
2407 retval = allocate_value (subobj_type);
2408 mark_value_bytes_unavailable (retval, 0,
2409 TYPE_LENGTH (subobj_type));
2412 else if (ex.error == NO_ENTRY_VALUE_ERROR)
2414 if (entry_values_debug)
2415 exception_print (gdb_stdout, ex);
2416 free_values.free_to_mark ();
2417 return allocate_optimized_out_value (subobj_type);
2420 throw_exception (ex);
2424 if (ctx.pieces.size () > 0)
2426 struct piece_closure *c;
2427 ULONGEST bit_size = 0;
2429 for (dwarf_expr_piece &piece : ctx.pieces)
2430 bit_size += piece.size;
2431 /* Complain if the expression is larger than the size of the
2433 if (bit_size > 8 * TYPE_LENGTH (type))
2434 invalid_synthetic_pointer ();
2436 c = allocate_piece_closure (per_cu, std::move (ctx.pieces), frame);
2437 /* We must clean up the value chain after creating the piece
2438 closure but before allocating the result. */
2439 free_values.free_to_mark ();
2440 retval = allocate_computed_value (subobj_type,
2441 &pieced_value_funcs, c);
2442 set_value_offset (retval, subobj_byte_offset);
2446 switch (ctx.location)
2448 case DWARF_VALUE_REGISTER:
2450 struct gdbarch *arch = get_frame_arch (frame);
2452 = longest_to_int (value_as_long (ctx.fetch (0)));
2453 int gdb_regnum = dwarf_reg_to_regnum_or_error (arch, dwarf_regnum);
2455 if (subobj_byte_offset != 0)
2456 error (_("cannot use offset on synthetic pointer to register"));
2457 free_values.free_to_mark ();
2458 retval = value_from_register (subobj_type, gdb_regnum, frame);
2459 if (value_optimized_out (retval))
2463 /* This means the register has undefined value / was
2464 not saved. As we're computing the location of some
2465 variable etc. in the program, not a value for
2466 inspecting a register ($pc, $sp, etc.), return a
2467 generic optimized out value instead, so that we show
2468 <optimized out> instead of <not saved>. */
2469 tmp = allocate_value (subobj_type);
2470 value_contents_copy (tmp, 0, retval, 0,
2471 TYPE_LENGTH (subobj_type));
2477 case DWARF_VALUE_MEMORY:
2479 struct type *ptr_type;
2480 CORE_ADDR address = ctx.fetch_address (0);
2481 bool in_stack_memory = ctx.fetch_in_stack_memory (0);
2483 /* DW_OP_deref_size (and possibly other operations too) may
2484 create a pointer instead of an address. Ideally, the
2485 pointer to address conversion would be performed as part
2486 of those operations, but the type of the object to
2487 which the address refers is not known at the time of
2488 the operation. Therefore, we do the conversion here
2489 since the type is readily available. */
2491 switch (TYPE_CODE (subobj_type))
2493 case TYPE_CODE_FUNC:
2494 case TYPE_CODE_METHOD:
2495 ptr_type = builtin_type (ctx.gdbarch)->builtin_func_ptr;
2498 ptr_type = builtin_type (ctx.gdbarch)->builtin_data_ptr;
2501 address = value_as_address (value_from_pointer (ptr_type, address));
2503 free_values.free_to_mark ();
2504 retval = value_at_lazy (subobj_type,
2505 address + subobj_byte_offset);
2506 if (in_stack_memory)
2507 set_value_stack (retval, 1);
2511 case DWARF_VALUE_STACK:
2513 struct value *value = ctx.fetch (0);
2514 size_t n = TYPE_LENGTH (value_type (value));
2515 size_t len = TYPE_LENGTH (subobj_type);
2516 size_t max = TYPE_LENGTH (type);
2517 struct gdbarch *objfile_gdbarch = get_objfile_arch (objfile);
2519 if (subobj_byte_offset + len > max)
2520 invalid_synthetic_pointer ();
2522 /* Preserve VALUE because we are going to free values back
2523 to the mark, but we still need the value contents
2525 value_ref_ptr value_holder = value_ref_ptr::new_reference (value);
2526 free_values.free_to_mark ();
2528 retval = allocate_value (subobj_type);
2530 /* The given offset is relative to the actual object. */
2531 if (gdbarch_byte_order (objfile_gdbarch) == BFD_ENDIAN_BIG)
2532 subobj_byte_offset += n - max;
2534 memcpy (value_contents_raw (retval),
2535 value_contents_all (value) + subobj_byte_offset, len);
2539 case DWARF_VALUE_LITERAL:
2542 size_t n = TYPE_LENGTH (subobj_type);
2544 if (subobj_byte_offset + n > ctx.len)
2545 invalid_synthetic_pointer ();
2547 free_values.free_to_mark ();
2548 retval = allocate_value (subobj_type);
2549 contents = value_contents_raw (retval);
2550 memcpy (contents, ctx.data + subobj_byte_offset, n);
2554 case DWARF_VALUE_OPTIMIZED_OUT:
2555 free_values.free_to_mark ();
2556 retval = allocate_optimized_out_value (subobj_type);
2559 /* DWARF_VALUE_IMPLICIT_POINTER was converted to a pieced
2560 operation by execute_stack_op. */
2561 case DWARF_VALUE_IMPLICIT_POINTER:
2562 /* DWARF_VALUE_OPTIMIZED_OUT can't occur in this context --
2563 it can only be encountered when making a piece. */
2565 internal_error (__FILE__, __LINE__, _("invalid location type"));
2569 set_value_initialized (retval, ctx.initialized);
2574 /* The exported interface to dwarf2_evaluate_loc_desc_full; it always
2575 passes 0 as the byte_offset. */
2578 dwarf2_evaluate_loc_desc (struct type *type, struct frame_info *frame,
2579 const gdb_byte *data, size_t size,
2580 struct dwarf2_per_cu_data *per_cu)
2582 return dwarf2_evaluate_loc_desc_full (type, frame, data, size, per_cu,
2586 /* Evaluates a dwarf expression and stores the result in VAL, expecting
2587 that the dwarf expression only produces a single CORE_ADDR. FRAME is the
2588 frame in which the expression is evaluated. ADDR is a context (location of
2589 a variable) and might be needed to evaluate the location expression.
2590 Returns 1 on success, 0 otherwise. */
2593 dwarf2_locexpr_baton_eval (const struct dwarf2_locexpr_baton *dlbaton,
2594 struct frame_info *frame,
2598 struct objfile *objfile;
2600 if (dlbaton == NULL || dlbaton->size == 0)
2603 dwarf_evaluate_loc_desc ctx;
2606 ctx.per_cu = dlbaton->per_cu;
2607 ctx.obj_address = addr;
2609 objfile = dwarf2_per_cu_objfile (dlbaton->per_cu);
2611 ctx.gdbarch = get_objfile_arch (objfile);
2612 ctx.addr_size = dwarf2_per_cu_addr_size (dlbaton->per_cu);
2613 ctx.ref_addr_size = dwarf2_per_cu_ref_addr_size (dlbaton->per_cu);
2614 ctx.offset = dwarf2_per_cu_text_offset (dlbaton->per_cu);
2618 ctx.eval (dlbaton->data, dlbaton->size);
2620 CATCH (ex, RETURN_MASK_ERROR)
2622 if (ex.error == NOT_AVAILABLE_ERROR)
2626 else if (ex.error == NO_ENTRY_VALUE_ERROR)
2628 if (entry_values_debug)
2629 exception_print (gdb_stdout, ex);
2633 throw_exception (ex);
2637 switch (ctx.location)
2639 case DWARF_VALUE_REGISTER:
2640 case DWARF_VALUE_MEMORY:
2641 case DWARF_VALUE_STACK:
2642 *valp = ctx.fetch_address (0);
2643 if (ctx.location == DWARF_VALUE_REGISTER)
2644 *valp = ctx.read_addr_from_reg (*valp);
2646 case DWARF_VALUE_LITERAL:
2647 *valp = extract_signed_integer (ctx.data, ctx.len,
2648 gdbarch_byte_order (ctx.gdbarch));
2650 /* Unsupported dwarf values. */
2651 case DWARF_VALUE_OPTIMIZED_OUT:
2652 case DWARF_VALUE_IMPLICIT_POINTER:
2659 /* See dwarf2loc.h. */
2662 dwarf2_evaluate_property (const struct dynamic_prop *prop,
2663 struct frame_info *frame,
2664 struct property_addr_info *addr_stack,
2670 if (frame == NULL && has_stack_frames ())
2671 frame = get_selected_frame (NULL);
2677 const struct dwarf2_property_baton *baton
2678 = (const struct dwarf2_property_baton *) prop->data.baton;
2680 if (dwarf2_locexpr_baton_eval (&baton->locexpr, frame,
2681 addr_stack ? addr_stack->addr : 0,
2684 if (baton->referenced_type)
2686 struct value *val = value_at (baton->referenced_type, *value);
2688 *value = value_as_address (val);
2697 struct dwarf2_property_baton *baton
2698 = (struct dwarf2_property_baton *) prop->data.baton;
2699 CORE_ADDR pc = get_frame_address_in_block (frame);
2700 const gdb_byte *data;
2704 data = dwarf2_find_location_expression (&baton->loclist, &size, pc);
2707 val = dwarf2_evaluate_loc_desc (baton->referenced_type, frame, data,
2708 size, baton->loclist.per_cu);
2709 if (!value_optimized_out (val))
2711 *value = value_as_address (val);
2719 *value = prop->data.const_val;
2722 case PROP_ADDR_OFFSET:
2724 struct dwarf2_property_baton *baton
2725 = (struct dwarf2_property_baton *) prop->data.baton;
2726 struct property_addr_info *pinfo;
2729 for (pinfo = addr_stack; pinfo != NULL; pinfo = pinfo->next)
2730 if (pinfo->type == baton->referenced_type)
2733 error (_("cannot find reference address for offset property"));
2734 if (pinfo->valaddr != NULL)
2735 val = value_from_contents
2736 (baton->offset_info.type,
2737 pinfo->valaddr + baton->offset_info.offset);
2739 val = value_at (baton->offset_info.type,
2740 pinfo->addr + baton->offset_info.offset);
2741 *value = value_as_address (val);
2749 /* See dwarf2loc.h. */
2752 dwarf2_compile_property_to_c (string_file *stream,
2753 const char *result_name,
2754 struct gdbarch *gdbarch,
2755 unsigned char *registers_used,
2756 const struct dynamic_prop *prop,
2760 struct dwarf2_property_baton *baton
2761 = (struct dwarf2_property_baton *) prop->data.baton;
2762 const gdb_byte *data;
2764 struct dwarf2_per_cu_data *per_cu;
2766 if (prop->kind == PROP_LOCEXPR)
2768 data = baton->locexpr.data;
2769 size = baton->locexpr.size;
2770 per_cu = baton->locexpr.per_cu;
2774 gdb_assert (prop->kind == PROP_LOCLIST);
2776 data = dwarf2_find_location_expression (&baton->loclist, &size, pc);
2777 per_cu = baton->loclist.per_cu;
2780 compile_dwarf_bounds_to_c (stream, result_name, prop, sym, pc,
2781 gdbarch, registers_used,
2782 dwarf2_per_cu_addr_size (per_cu),
2783 data, data + size, per_cu);
2787 /* Helper functions and baton for dwarf2_loc_desc_get_symbol_read_needs. */
2789 class symbol_needs_eval_context : public dwarf_expr_context
2793 enum symbol_needs_kind needs;
2794 struct dwarf2_per_cu_data *per_cu;
2796 /* Reads from registers do require a frame. */
2797 CORE_ADDR read_addr_from_reg (int regnum) override
2799 needs = SYMBOL_NEEDS_FRAME;
2803 /* "get_reg_value" callback: Reads from registers do require a
2806 struct value *get_reg_value (struct type *type, int regnum) override
2808 needs = SYMBOL_NEEDS_FRAME;
2809 return value_zero (type, not_lval);
2812 /* Reads from memory do not require a frame. */
2813 void read_mem (gdb_byte *buf, CORE_ADDR addr, size_t len) override
2815 memset (buf, 0, len);
2818 /* Frame-relative accesses do require a frame. */
2819 void get_frame_base (const gdb_byte **start, size_t *length) override
2821 static gdb_byte lit0 = DW_OP_lit0;
2826 needs = SYMBOL_NEEDS_FRAME;
2829 /* CFA accesses require a frame. */
2830 CORE_ADDR get_frame_cfa () override
2832 needs = SYMBOL_NEEDS_FRAME;
2836 CORE_ADDR get_frame_pc () override
2838 needs = SYMBOL_NEEDS_FRAME;
2842 /* Thread-local accesses require registers, but not a frame. */
2843 CORE_ADDR get_tls_address (CORE_ADDR offset) override
2845 if (needs <= SYMBOL_NEEDS_REGISTERS)
2846 needs = SYMBOL_NEEDS_REGISTERS;
2850 /* Helper interface of per_cu_dwarf_call for
2851 dwarf2_loc_desc_get_symbol_read_needs. */
2853 void dwarf_call (cu_offset die_offset) override
2855 per_cu_dwarf_call (this, die_offset, per_cu);
2858 /* Helper interface of sect_variable_value for
2859 dwarf2_loc_desc_get_symbol_read_needs. */
2861 struct value *dwarf_variable_value (sect_offset sect_off) override
2863 return sect_variable_value (this, sect_off, per_cu);
2866 /* DW_OP_entry_value accesses require a caller, therefore a
2869 void push_dwarf_reg_entry_value (enum call_site_parameter_kind kind,
2870 union call_site_parameter_u kind_u,
2871 int deref_size) override
2873 needs = SYMBOL_NEEDS_FRAME;
2875 /* The expression may require some stub values on DWARF stack. */
2876 push_address (0, 0);
2879 /* DW_OP_GNU_addr_index doesn't require a frame. */
2881 CORE_ADDR get_addr_index (unsigned int index) override
2883 /* Nothing to do. */
2887 /* DW_OP_push_object_address has a frame already passed through. */
2889 CORE_ADDR get_object_address () override
2891 /* Nothing to do. */
2896 /* Compute the correct symbol_needs_kind value for the location
2897 expression at DATA (length SIZE). */
2899 static enum symbol_needs_kind
2900 dwarf2_loc_desc_get_symbol_read_needs (const gdb_byte *data, size_t size,
2901 struct dwarf2_per_cu_data *per_cu)
2904 struct objfile *objfile = dwarf2_per_cu_objfile (per_cu);
2906 scoped_value_mark free_values;
2908 symbol_needs_eval_context ctx;
2910 ctx.needs = SYMBOL_NEEDS_NONE;
2911 ctx.per_cu = per_cu;
2912 ctx.gdbarch = get_objfile_arch (objfile);
2913 ctx.addr_size = dwarf2_per_cu_addr_size (per_cu);
2914 ctx.ref_addr_size = dwarf2_per_cu_ref_addr_size (per_cu);
2915 ctx.offset = dwarf2_per_cu_text_offset (per_cu);
2917 ctx.eval (data, size);
2919 in_reg = ctx.location == DWARF_VALUE_REGISTER;
2921 /* If the location has several pieces, and any of them are in
2922 registers, then we will need a frame to fetch them from. */
2923 for (dwarf_expr_piece &p : ctx.pieces)
2924 if (p.location == DWARF_VALUE_REGISTER)
2928 ctx.needs = SYMBOL_NEEDS_FRAME;
2932 /* A helper function that throws an unimplemented error mentioning a
2933 given DWARF operator. */
2935 static void ATTRIBUTE_NORETURN
2936 unimplemented (unsigned int op)
2938 const char *name = get_DW_OP_name (op);
2941 error (_("DWARF operator %s cannot be translated to an agent expression"),
2944 error (_("Unknown DWARF operator 0x%02x cannot be translated "
2945 "to an agent expression"),
2951 This is basically a wrapper on gdbarch_dwarf2_reg_to_regnum so that we
2952 can issue a complaint, which is better than having every target's
2953 implementation of dwarf2_reg_to_regnum do it. */
2956 dwarf_reg_to_regnum (struct gdbarch *arch, int dwarf_reg)
2958 int reg = gdbarch_dwarf2_reg_to_regnum (arch, dwarf_reg);
2962 complaint (_("bad DWARF register number %d"), dwarf_reg);
2967 /* Subroutine of dwarf_reg_to_regnum_or_error to simplify it.
2968 Throw an error because DWARF_REG is bad. */
2971 throw_bad_regnum_error (ULONGEST dwarf_reg)
2973 /* Still want to print -1 as "-1".
2974 We *could* have int and ULONGEST versions of dwarf2_reg_to_regnum_or_error
2975 but that's overkill for now. */
2976 if ((int) dwarf_reg == dwarf_reg)
2977 error (_("Unable to access DWARF register number %d"), (int) dwarf_reg);
2978 error (_("Unable to access DWARF register number %s"),
2979 pulongest (dwarf_reg));
2982 /* See dwarf2loc.h. */
2985 dwarf_reg_to_regnum_or_error (struct gdbarch *arch, ULONGEST dwarf_reg)
2989 if (dwarf_reg > INT_MAX)
2990 throw_bad_regnum_error (dwarf_reg);
2991 /* Yes, we will end up issuing a complaint and an error if DWARF_REG is
2992 bad, but that's ok. */
2993 reg = dwarf_reg_to_regnum (arch, (int) dwarf_reg);
2995 throw_bad_regnum_error (dwarf_reg);
2999 /* A helper function that emits an access to memory. ARCH is the
3000 target architecture. EXPR is the expression which we are building.
3001 NBITS is the number of bits we want to read. This emits the
3002 opcodes needed to read the memory and then extract the desired
3006 access_memory (struct gdbarch *arch, struct agent_expr *expr, ULONGEST nbits)
3008 ULONGEST nbytes = (nbits + 7) / 8;
3010 gdb_assert (nbytes > 0 && nbytes <= sizeof (LONGEST));
3013 ax_trace_quick (expr, nbytes);
3016 ax_simple (expr, aop_ref8);
3017 else if (nbits <= 16)
3018 ax_simple (expr, aop_ref16);
3019 else if (nbits <= 32)
3020 ax_simple (expr, aop_ref32);
3022 ax_simple (expr, aop_ref64);
3024 /* If we read exactly the number of bytes we wanted, we're done. */
3025 if (8 * nbytes == nbits)
3028 if (gdbarch_bits_big_endian (arch))
3030 /* On a bits-big-endian machine, we want the high-order
3032 ax_const_l (expr, 8 * nbytes - nbits);
3033 ax_simple (expr, aop_rsh_unsigned);
3037 /* On a bits-little-endian box, we want the low-order NBITS. */
3038 ax_zero_ext (expr, nbits);
3042 /* A helper function to return the frame's PC. */
3045 get_ax_pc (void *baton)
3047 struct agent_expr *expr = (struct agent_expr *) baton;
3052 /* Compile a DWARF location expression to an agent expression.
3054 EXPR is the agent expression we are building.
3055 LOC is the agent value we modify.
3056 ARCH is the architecture.
3057 ADDR_SIZE is the size of addresses, in bytes.
3058 OP_PTR is the start of the location expression.
3059 OP_END is one past the last byte of the location expression.
3061 This will throw an exception for various kinds of errors -- for
3062 example, if the expression cannot be compiled, or if the expression
3066 dwarf2_compile_expr_to_ax (struct agent_expr *expr, struct axs_value *loc,
3067 unsigned int addr_size, const gdb_byte *op_ptr,
3068 const gdb_byte *op_end,
3069 struct dwarf2_per_cu_data *per_cu)
3071 gdbarch *arch = expr->gdbarch;
3072 std::vector<int> dw_labels, patches;
3073 const gdb_byte * const base = op_ptr;
3074 const gdb_byte *previous_piece = op_ptr;
3075 enum bfd_endian byte_order = gdbarch_byte_order (arch);
3076 ULONGEST bits_collected = 0;
3077 unsigned int addr_size_bits = 8 * addr_size;
3078 int bits_big_endian = gdbarch_bits_big_endian (arch);
3080 std::vector<int> offsets (op_end - op_ptr, -1);
3082 /* By default we are making an address. */
3083 loc->kind = axs_lvalue_memory;
3085 while (op_ptr < op_end)
3087 enum dwarf_location_atom op = (enum dwarf_location_atom) *op_ptr;
3088 uint64_t uoffset, reg;
3092 offsets[op_ptr - base] = expr->len;
3095 /* Our basic approach to code generation is to map DWARF
3096 operations directly to AX operations. However, there are
3099 First, DWARF works on address-sized units, but AX always uses
3100 LONGEST. For most operations we simply ignore this
3101 difference; instead we generate sign extensions as needed
3102 before division and comparison operations. It would be nice
3103 to omit the sign extensions, but there is no way to determine
3104 the size of the target's LONGEST. (This code uses the size
3105 of the host LONGEST in some cases -- that is a bug but it is
3108 Second, some DWARF operations cannot be translated to AX.
3109 For these we simply fail. See
3110 http://sourceware.org/bugzilla/show_bug.cgi?id=11662. */
3145 ax_const_l (expr, op - DW_OP_lit0);
3149 uoffset = extract_unsigned_integer (op_ptr, addr_size, byte_order);
3150 op_ptr += addr_size;
3151 /* Some versions of GCC emit DW_OP_addr before
3152 DW_OP_GNU_push_tls_address. In this case the value is an
3153 index, not an address. We don't support things like
3154 branching between the address and the TLS op. */
3155 if (op_ptr >= op_end || *op_ptr != DW_OP_GNU_push_tls_address)
3156 uoffset += dwarf2_per_cu_text_offset (per_cu);
3157 ax_const_l (expr, uoffset);
3161 ax_const_l (expr, extract_unsigned_integer (op_ptr, 1, byte_order));
3165 ax_const_l (expr, extract_signed_integer (op_ptr, 1, byte_order));
3169 ax_const_l (expr, extract_unsigned_integer (op_ptr, 2, byte_order));
3173 ax_const_l (expr, extract_signed_integer (op_ptr, 2, byte_order));
3177 ax_const_l (expr, extract_unsigned_integer (op_ptr, 4, byte_order));
3181 ax_const_l (expr, extract_signed_integer (op_ptr, 4, byte_order));
3185 ax_const_l (expr, extract_unsigned_integer (op_ptr, 8, byte_order));
3189 ax_const_l (expr, extract_signed_integer (op_ptr, 8, byte_order));
3193 op_ptr = safe_read_uleb128 (op_ptr, op_end, &uoffset);
3194 ax_const_l (expr, uoffset);
3197 op_ptr = safe_read_sleb128 (op_ptr, op_end, &offset);
3198 ax_const_l (expr, offset);
3233 dwarf_expr_require_composition (op_ptr, op_end, "DW_OP_regx");
3234 loc->u.reg = dwarf_reg_to_regnum_or_error (arch, op - DW_OP_reg0);
3235 loc->kind = axs_lvalue_register;
3239 op_ptr = safe_read_uleb128 (op_ptr, op_end, ®);
3240 dwarf_expr_require_composition (op_ptr, op_end, "DW_OP_regx");
3241 loc->u.reg = dwarf_reg_to_regnum_or_error (arch, reg);
3242 loc->kind = axs_lvalue_register;
3245 case DW_OP_implicit_value:
3249 op_ptr = safe_read_uleb128 (op_ptr, op_end, &len);
3250 if (op_ptr + len > op_end)
3251 error (_("DW_OP_implicit_value: too few bytes available."));
3252 if (len > sizeof (ULONGEST))
3253 error (_("Cannot translate DW_OP_implicit_value of %d bytes"),
3256 ax_const_l (expr, extract_unsigned_integer (op_ptr, len,
3259 dwarf_expr_require_composition (op_ptr, op_end,
3260 "DW_OP_implicit_value");
3262 loc->kind = axs_rvalue;
3266 case DW_OP_stack_value:
3267 dwarf_expr_require_composition (op_ptr, op_end, "DW_OP_stack_value");
3268 loc->kind = axs_rvalue;
3303 op_ptr = safe_read_sleb128 (op_ptr, op_end, &offset);
3304 i = dwarf_reg_to_regnum_or_error (arch, op - DW_OP_breg0);
3308 ax_const_l (expr, offset);
3309 ax_simple (expr, aop_add);
3314 op_ptr = safe_read_uleb128 (op_ptr, op_end, ®);
3315 op_ptr = safe_read_sleb128 (op_ptr, op_end, &offset);
3316 i = dwarf_reg_to_regnum_or_error (arch, reg);
3320 ax_const_l (expr, offset);
3321 ax_simple (expr, aop_add);
3327 const gdb_byte *datastart;
3329 const struct block *b;
3330 struct symbol *framefunc;
3332 b = block_for_pc (expr->scope);
3335 error (_("No block found for address"));
3337 framefunc = block_linkage_function (b);
3340 error (_("No function found for block"));
3342 func_get_frame_base_dwarf_block (framefunc, expr->scope,
3343 &datastart, &datalen);
3345 op_ptr = safe_read_sleb128 (op_ptr, op_end, &offset);
3346 dwarf2_compile_expr_to_ax (expr, loc, addr_size, datastart,
3347 datastart + datalen, per_cu);
3348 if (loc->kind == axs_lvalue_register)
3349 require_rvalue (expr, loc);
3353 ax_const_l (expr, offset);
3354 ax_simple (expr, aop_add);
3357 loc->kind = axs_lvalue_memory;
3362 ax_simple (expr, aop_dup);
3366 ax_simple (expr, aop_pop);
3371 ax_pick (expr, offset);
3375 ax_simple (expr, aop_swap);
3383 ax_simple (expr, aop_rot);
3387 case DW_OP_deref_size:
3391 if (op == DW_OP_deref_size)
3396 if (size != 1 && size != 2 && size != 4 && size != 8)
3397 error (_("Unsupported size %d in %s"),
3398 size, get_DW_OP_name (op));
3399 access_memory (arch, expr, size * TARGET_CHAR_BIT);
3404 /* Sign extend the operand. */
3405 ax_ext (expr, addr_size_bits);
3406 ax_simple (expr, aop_dup);
3407 ax_const_l (expr, 0);
3408 ax_simple (expr, aop_less_signed);
3409 ax_simple (expr, aop_log_not);
3410 i = ax_goto (expr, aop_if_goto);
3411 /* We have to emit 0 - X. */
3412 ax_const_l (expr, 0);
3413 ax_simple (expr, aop_swap);
3414 ax_simple (expr, aop_sub);
3415 ax_label (expr, i, expr->len);
3419 /* No need to sign extend here. */
3420 ax_const_l (expr, 0);
3421 ax_simple (expr, aop_swap);
3422 ax_simple (expr, aop_sub);
3426 /* Sign extend the operand. */
3427 ax_ext (expr, addr_size_bits);
3428 ax_simple (expr, aop_bit_not);
3431 case DW_OP_plus_uconst:
3432 op_ptr = safe_read_uleb128 (op_ptr, op_end, ®);
3433 /* It would be really weird to emit `DW_OP_plus_uconst 0',
3434 but we micro-optimize anyhow. */
3437 ax_const_l (expr, reg);
3438 ax_simple (expr, aop_add);
3443 ax_simple (expr, aop_bit_and);
3447 /* Sign extend the operands. */
3448 ax_ext (expr, addr_size_bits);
3449 ax_simple (expr, aop_swap);
3450 ax_ext (expr, addr_size_bits);
3451 ax_simple (expr, aop_swap);
3452 ax_simple (expr, aop_div_signed);
3456 ax_simple (expr, aop_sub);
3460 ax_simple (expr, aop_rem_unsigned);
3464 ax_simple (expr, aop_mul);
3468 ax_simple (expr, aop_bit_or);
3472 ax_simple (expr, aop_add);
3476 ax_simple (expr, aop_lsh);
3480 ax_simple (expr, aop_rsh_unsigned);
3484 ax_simple (expr, aop_rsh_signed);
3488 ax_simple (expr, aop_bit_xor);
3492 /* Sign extend the operands. */
3493 ax_ext (expr, addr_size_bits);
3494 ax_simple (expr, aop_swap);
3495 ax_ext (expr, addr_size_bits);
3496 /* Note no swap here: A <= B is !(B < A). */
3497 ax_simple (expr, aop_less_signed);
3498 ax_simple (expr, aop_log_not);
3502 /* Sign extend the operands. */
3503 ax_ext (expr, addr_size_bits);
3504 ax_simple (expr, aop_swap);
3505 ax_ext (expr, addr_size_bits);
3506 ax_simple (expr, aop_swap);
3507 /* A >= B is !(A < B). */
3508 ax_simple (expr, aop_less_signed);
3509 ax_simple (expr, aop_log_not);
3513 /* Sign extend the operands. */
3514 ax_ext (expr, addr_size_bits);
3515 ax_simple (expr, aop_swap);
3516 ax_ext (expr, addr_size_bits);
3517 /* No need for a second swap here. */
3518 ax_simple (expr, aop_equal);
3522 /* Sign extend the operands. */
3523 ax_ext (expr, addr_size_bits);
3524 ax_simple (expr, aop_swap);
3525 ax_ext (expr, addr_size_bits);
3526 ax_simple (expr, aop_swap);
3527 ax_simple (expr, aop_less_signed);
3531 /* Sign extend the operands. */
3532 ax_ext (expr, addr_size_bits);
3533 ax_simple (expr, aop_swap);
3534 ax_ext (expr, addr_size_bits);
3535 /* Note no swap here: A > B is B < A. */
3536 ax_simple (expr, aop_less_signed);
3540 /* Sign extend the operands. */
3541 ax_ext (expr, addr_size_bits);
3542 ax_simple (expr, aop_swap);
3543 ax_ext (expr, addr_size_bits);
3544 /* No need for a swap here. */
3545 ax_simple (expr, aop_equal);
3546 ax_simple (expr, aop_log_not);
3549 case DW_OP_call_frame_cfa:
3552 CORE_ADDR text_offset;
3554 const gdb_byte *cfa_start, *cfa_end;
3556 if (dwarf2_fetch_cfa_info (arch, expr->scope, per_cu,
3558 &text_offset, &cfa_start, &cfa_end))
3561 ax_reg (expr, regnum);
3564 ax_const_l (expr, off);
3565 ax_simple (expr, aop_add);
3570 /* Another expression. */
3571 ax_const_l (expr, text_offset);
3572 dwarf2_compile_expr_to_ax (expr, loc, addr_size, cfa_start,
3576 loc->kind = axs_lvalue_memory;
3580 case DW_OP_GNU_push_tls_address:
3581 case DW_OP_form_tls_address:
3585 case DW_OP_push_object_address:
3590 offset = extract_signed_integer (op_ptr, 2, byte_order);
3592 i = ax_goto (expr, aop_goto);
3593 dw_labels.push_back (op_ptr + offset - base);
3594 patches.push_back (i);
3598 offset = extract_signed_integer (op_ptr, 2, byte_order);
3600 /* Zero extend the operand. */
3601 ax_zero_ext (expr, addr_size_bits);
3602 i = ax_goto (expr, aop_if_goto);
3603 dw_labels.push_back (op_ptr + offset - base);
3604 patches.push_back (i);
3611 case DW_OP_bit_piece:
3615 if (op_ptr - 1 == previous_piece)
3616 error (_("Cannot translate empty pieces to agent expressions"));
3617 previous_piece = op_ptr - 1;
3619 op_ptr = safe_read_uleb128 (op_ptr, op_end, &size);
3620 if (op == DW_OP_piece)
3626 op_ptr = safe_read_uleb128 (op_ptr, op_end, &uoffset);
3628 if (bits_collected + size > 8 * sizeof (LONGEST))
3629 error (_("Expression pieces exceed word size"));
3631 /* Access the bits. */
3634 case axs_lvalue_register:
3635 ax_reg (expr, loc->u.reg);
3638 case axs_lvalue_memory:
3639 /* Offset the pointer, if needed. */
3642 ax_const_l (expr, uoffset / 8);
3643 ax_simple (expr, aop_add);
3646 access_memory (arch, expr, size);
3650 /* For a bits-big-endian target, shift up what we already
3651 have. For a bits-little-endian target, shift up the
3652 new data. Note that there is a potential bug here if
3653 the DWARF expression leaves multiple values on the
3655 if (bits_collected > 0)
3657 if (bits_big_endian)
3659 ax_simple (expr, aop_swap);
3660 ax_const_l (expr, size);
3661 ax_simple (expr, aop_lsh);
3662 /* We don't need a second swap here, because
3663 aop_bit_or is symmetric. */
3667 ax_const_l (expr, size);
3668 ax_simple (expr, aop_lsh);
3670 ax_simple (expr, aop_bit_or);
3673 bits_collected += size;
3674 loc->kind = axs_rvalue;
3678 case DW_OP_GNU_uninit:
3684 struct dwarf2_locexpr_baton block;
3685 int size = (op == DW_OP_call2 ? 2 : 4);
3687 uoffset = extract_unsigned_integer (op_ptr, size, byte_order);
3690 cu_offset cuoffset = (cu_offset) uoffset;
3691 block = dwarf2_fetch_die_loc_cu_off (cuoffset, per_cu,
3694 /* DW_OP_call_ref is currently not supported. */
3695 gdb_assert (block.per_cu == per_cu);
3697 dwarf2_compile_expr_to_ax (expr, loc, addr_size, block.data,
3698 block.data + block.size, per_cu);
3702 case DW_OP_call_ref:
3705 case DW_OP_GNU_variable_value:
3713 /* Patch all the branches we emitted. */
3714 for (int i = 0; i < patches.size (); ++i)
3716 int targ = offsets[dw_labels[i]];
3718 internal_error (__FILE__, __LINE__, _("invalid label"));
3719 ax_label (expr, patches[i], targ);
3724 /* Return the value of SYMBOL in FRAME using the DWARF-2 expression
3725 evaluator to calculate the location. */
3726 static struct value *
3727 locexpr_read_variable (struct symbol *symbol, struct frame_info *frame)
3729 struct dwarf2_locexpr_baton *dlbaton
3730 = (struct dwarf2_locexpr_baton *) SYMBOL_LOCATION_BATON (symbol);
3733 val = dwarf2_evaluate_loc_desc (SYMBOL_TYPE (symbol), frame, dlbaton->data,
3734 dlbaton->size, dlbaton->per_cu);
3739 /* Return the value of SYMBOL in FRAME at (callee) FRAME's function
3740 entry. SYMBOL should be a function parameter, otherwise NO_ENTRY_VALUE_ERROR
3743 static struct value *
3744 locexpr_read_variable_at_entry (struct symbol *symbol, struct frame_info *frame)
3746 struct dwarf2_locexpr_baton *dlbaton
3747 = (struct dwarf2_locexpr_baton *) SYMBOL_LOCATION_BATON (symbol);
3749 return value_of_dwarf_block_entry (SYMBOL_TYPE (symbol), frame, dlbaton->data,
3753 /* Implementation of get_symbol_read_needs from
3754 symbol_computed_ops. */
3756 static enum symbol_needs_kind
3757 locexpr_get_symbol_read_needs (struct symbol *symbol)
3759 struct dwarf2_locexpr_baton *dlbaton
3760 = (struct dwarf2_locexpr_baton *) SYMBOL_LOCATION_BATON (symbol);
3762 return dwarf2_loc_desc_get_symbol_read_needs (dlbaton->data, dlbaton->size,
3766 /* Return true if DATA points to the end of a piece. END is one past
3767 the last byte in the expression. */
3770 piece_end_p (const gdb_byte *data, const gdb_byte *end)
3772 return data == end || data[0] == DW_OP_piece || data[0] == DW_OP_bit_piece;
3775 /* Helper for locexpr_describe_location_piece that finds the name of a
3779 locexpr_regname (struct gdbarch *gdbarch, int dwarf_regnum)
3783 /* This doesn't use dwarf_reg_to_regnum_or_error on purpose.
3784 We'd rather print *something* here than throw an error. */
3785 regnum = dwarf_reg_to_regnum (gdbarch, dwarf_regnum);
3786 /* gdbarch_register_name may just return "", return something more
3787 descriptive for bad register numbers. */
3790 /* The text is output as "$bad_register_number".
3791 That is why we use the underscores. */
3792 return _("bad_register_number");
3794 return gdbarch_register_name (gdbarch, regnum);
3797 /* Nicely describe a single piece of a location, returning an updated
3798 position in the bytecode sequence. This function cannot recognize
3799 all locations; if a location is not recognized, it simply returns
3800 DATA. If there is an error during reading, e.g. we run off the end
3801 of the buffer, an error is thrown. */
3803 static const gdb_byte *
3804 locexpr_describe_location_piece (struct symbol *symbol, struct ui_file *stream,
3805 CORE_ADDR addr, struct objfile *objfile,
3806 struct dwarf2_per_cu_data *per_cu,
3807 const gdb_byte *data, const gdb_byte *end,
3808 unsigned int addr_size)
3810 struct gdbarch *gdbarch = get_objfile_arch (objfile);
3813 if (data[0] >= DW_OP_reg0 && data[0] <= DW_OP_reg31)
3815 fprintf_filtered (stream, _("a variable in $%s"),
3816 locexpr_regname (gdbarch, data[0] - DW_OP_reg0));
3819 else if (data[0] == DW_OP_regx)
3823 data = safe_read_uleb128 (data + 1, end, ®);
3824 fprintf_filtered (stream, _("a variable in $%s"),
3825 locexpr_regname (gdbarch, reg));
3827 else if (data[0] == DW_OP_fbreg)
3829 const struct block *b;
3830 struct symbol *framefunc;
3832 int64_t frame_offset;
3833 const gdb_byte *base_data, *new_data, *save_data = data;
3835 int64_t base_offset = 0;
3837 new_data = safe_read_sleb128 (data + 1, end, &frame_offset);
3838 if (!piece_end_p (new_data, end))
3842 b = block_for_pc (addr);
3845 error (_("No block found for address for symbol \"%s\"."),
3846 SYMBOL_PRINT_NAME (symbol));
3848 framefunc = block_linkage_function (b);
3851 error (_("No function found for block for symbol \"%s\"."),
3852 SYMBOL_PRINT_NAME (symbol));
3854 func_get_frame_base_dwarf_block (framefunc, addr, &base_data, &base_size);
3856 if (base_data[0] >= DW_OP_breg0 && base_data[0] <= DW_OP_breg31)
3858 const gdb_byte *buf_end;
3860 frame_reg = base_data[0] - DW_OP_breg0;
3861 buf_end = safe_read_sleb128 (base_data + 1, base_data + base_size,
3863 if (buf_end != base_data + base_size)
3864 error (_("Unexpected opcode after "
3865 "DW_OP_breg%u for symbol \"%s\"."),
3866 frame_reg, SYMBOL_PRINT_NAME (symbol));
3868 else if (base_data[0] >= DW_OP_reg0 && base_data[0] <= DW_OP_reg31)
3870 /* The frame base is just the register, with no offset. */
3871 frame_reg = base_data[0] - DW_OP_reg0;
3876 /* We don't know what to do with the frame base expression,
3877 so we can't trace this variable; give up. */
3881 fprintf_filtered (stream,
3882 _("a variable at frame base reg $%s offset %s+%s"),
3883 locexpr_regname (gdbarch, frame_reg),
3884 plongest (base_offset), plongest (frame_offset));
3886 else if (data[0] >= DW_OP_breg0 && data[0] <= DW_OP_breg31
3887 && piece_end_p (data, end))
3891 data = safe_read_sleb128 (data + 1, end, &offset);
3893 fprintf_filtered (stream,
3894 _("a variable at offset %s from base reg $%s"),
3896 locexpr_regname (gdbarch, data[0] - DW_OP_breg0));
3899 /* The location expression for a TLS variable looks like this (on a
3902 DW_AT_location : 10 byte block: 3 4 0 0 0 0 0 0 0 e0
3903 (DW_OP_addr: 4; DW_OP_GNU_push_tls_address)
3905 0x3 is the encoding for DW_OP_addr, which has an operand as long
3906 as the size of an address on the target machine (here is 8
3907 bytes). Note that more recent version of GCC emit DW_OP_const4u
3908 or DW_OP_const8u, depending on address size, rather than
3909 DW_OP_addr. 0xe0 is the encoding for DW_OP_GNU_push_tls_address.
3910 The operand represents the offset at which the variable is within
3911 the thread local storage. */
3913 else if (data + 1 + addr_size < end
3914 && (data[0] == DW_OP_addr
3915 || (addr_size == 4 && data[0] == DW_OP_const4u)
3916 || (addr_size == 8 && data[0] == DW_OP_const8u))
3917 && (data[1 + addr_size] == DW_OP_GNU_push_tls_address
3918 || data[1 + addr_size] == DW_OP_form_tls_address)
3919 && piece_end_p (data + 2 + addr_size, end))
3922 offset = extract_unsigned_integer (data + 1, addr_size,
3923 gdbarch_byte_order (gdbarch));
3925 fprintf_filtered (stream,
3926 _("a thread-local variable at offset 0x%s "
3927 "in the thread-local storage for `%s'"),
3928 phex_nz (offset, addr_size), objfile_name (objfile));
3930 data += 1 + addr_size + 1;
3933 /* With -gsplit-dwarf a TLS variable can also look like this:
3934 DW_AT_location : 3 byte block: fc 4 e0
3935 (DW_OP_GNU_const_index: 4;
3936 DW_OP_GNU_push_tls_address) */
3937 else if (data + 3 <= end
3938 && data + 1 + (leb128_size = skip_leb128 (data + 1, end)) < end
3939 && data[0] == DW_OP_GNU_const_index
3941 && (data[1 + leb128_size] == DW_OP_GNU_push_tls_address
3942 || data[1 + leb128_size] == DW_OP_form_tls_address)
3943 && piece_end_p (data + 2 + leb128_size, end))
3947 data = safe_read_uleb128 (data + 1, end, &offset);
3948 offset = dwarf2_read_addr_index (per_cu, offset);
3949 fprintf_filtered (stream,
3950 _("a thread-local variable at offset 0x%s "
3951 "in the thread-local storage for `%s'"),
3952 phex_nz (offset, addr_size), objfile_name (objfile));
3956 else if (data[0] >= DW_OP_lit0
3957 && data[0] <= DW_OP_lit31
3959 && data[1] == DW_OP_stack_value)
3961 fprintf_filtered (stream, _("the constant %d"), data[0] - DW_OP_lit0);
3968 /* Disassemble an expression, stopping at the end of a piece or at the
3969 end of the expression. Returns a pointer to the next unread byte
3970 in the input expression. If ALL is nonzero, then this function
3971 will keep going until it reaches the end of the expression.
3972 If there is an error during reading, e.g. we run off the end
3973 of the buffer, an error is thrown. */
3975 static const gdb_byte *
3976 disassemble_dwarf_expression (struct ui_file *stream,
3977 struct gdbarch *arch, unsigned int addr_size,
3978 int offset_size, const gdb_byte *start,
3979 const gdb_byte *data, const gdb_byte *end,
3980 int indent, int all,
3981 struct dwarf2_per_cu_data *per_cu)
3985 || (data[0] != DW_OP_piece && data[0] != DW_OP_bit_piece)))
3987 enum dwarf_location_atom op = (enum dwarf_location_atom) *data++;
3992 name = get_DW_OP_name (op);
3995 error (_("Unrecognized DWARF opcode 0x%02x at %ld"),
3996 op, (long) (data - 1 - start));
3997 fprintf_filtered (stream, " %*ld: %s", indent + 4,
3998 (long) (data - 1 - start), name);
4003 ul = extract_unsigned_integer (data, addr_size,
4004 gdbarch_byte_order (arch));
4006 fprintf_filtered (stream, " 0x%s", phex_nz (ul, addr_size));
4010 ul = extract_unsigned_integer (data, 1, gdbarch_byte_order (arch));
4012 fprintf_filtered (stream, " %s", pulongest (ul));
4015 l = extract_signed_integer (data, 1, gdbarch_byte_order (arch));
4017 fprintf_filtered (stream, " %s", plongest (l));
4020 ul = extract_unsigned_integer (data, 2, gdbarch_byte_order (arch));
4022 fprintf_filtered (stream, " %s", pulongest (ul));
4025 l = extract_signed_integer (data, 2, gdbarch_byte_order (arch));
4027 fprintf_filtered (stream, " %s", plongest (l));
4030 ul = extract_unsigned_integer (data, 4, gdbarch_byte_order (arch));
4032 fprintf_filtered (stream, " %s", pulongest (ul));
4035 l = extract_signed_integer (data, 4, gdbarch_byte_order (arch));
4037 fprintf_filtered (stream, " %s", plongest (l));
4040 ul = extract_unsigned_integer (data, 8, gdbarch_byte_order (arch));
4042 fprintf_filtered (stream, " %s", pulongest (ul));
4045 l = extract_signed_integer (data, 8, gdbarch_byte_order (arch));
4047 fprintf_filtered (stream, " %s", plongest (l));
4050 data = safe_read_uleb128 (data, end, &ul);
4051 fprintf_filtered (stream, " %s", pulongest (ul));
4054 data = safe_read_sleb128 (data, end, &l);
4055 fprintf_filtered (stream, " %s", plongest (l));
4090 fprintf_filtered (stream, " [$%s]",
4091 locexpr_regname (arch, op - DW_OP_reg0));
4095 data = safe_read_uleb128 (data, end, &ul);
4096 fprintf_filtered (stream, " %s [$%s]", pulongest (ul),
4097 locexpr_regname (arch, (int) ul));
4100 case DW_OP_implicit_value:
4101 data = safe_read_uleb128 (data, end, &ul);
4103 fprintf_filtered (stream, " %s", pulongest (ul));
4138 data = safe_read_sleb128 (data, end, &l);
4139 fprintf_filtered (stream, " %s [$%s]", plongest (l),
4140 locexpr_regname (arch, op - DW_OP_breg0));
4144 data = safe_read_uleb128 (data, end, &ul);
4145 data = safe_read_sleb128 (data, end, &l);
4146 fprintf_filtered (stream, " register %s [$%s] offset %s",
4148 locexpr_regname (arch, (int) ul),
4153 data = safe_read_sleb128 (data, end, &l);
4154 fprintf_filtered (stream, " %s", plongest (l));
4157 case DW_OP_xderef_size:
4158 case DW_OP_deref_size:
4160 fprintf_filtered (stream, " %d", *data);
4164 case DW_OP_plus_uconst:
4165 data = safe_read_uleb128 (data, end, &ul);
4166 fprintf_filtered (stream, " %s", pulongest (ul));
4170 l = extract_signed_integer (data, 2, gdbarch_byte_order (arch));
4172 fprintf_filtered (stream, " to %ld",
4173 (long) (data + l - start));
4177 l = extract_signed_integer (data, 2, gdbarch_byte_order (arch));
4179 fprintf_filtered (stream, " %ld",
4180 (long) (data + l - start));
4184 ul = extract_unsigned_integer (data, 2, gdbarch_byte_order (arch));
4186 fprintf_filtered (stream, " offset %s", phex_nz (ul, 2));
4190 ul = extract_unsigned_integer (data, 4, gdbarch_byte_order (arch));
4192 fprintf_filtered (stream, " offset %s", phex_nz (ul, 4));
4195 case DW_OP_call_ref:
4196 ul = extract_unsigned_integer (data, offset_size,
4197 gdbarch_byte_order (arch));
4198 data += offset_size;
4199 fprintf_filtered (stream, " offset %s", phex_nz (ul, offset_size));
4203 data = safe_read_uleb128 (data, end, &ul);
4204 fprintf_filtered (stream, " %s (bytes)", pulongest (ul));
4207 case DW_OP_bit_piece:
4211 data = safe_read_uleb128 (data, end, &ul);
4212 data = safe_read_uleb128 (data, end, &offset);
4213 fprintf_filtered (stream, " size %s offset %s (bits)",
4214 pulongest (ul), pulongest (offset));
4218 case DW_OP_implicit_pointer:
4219 case DW_OP_GNU_implicit_pointer:
4221 ul = extract_unsigned_integer (data, offset_size,
4222 gdbarch_byte_order (arch));
4223 data += offset_size;
4225 data = safe_read_sleb128 (data, end, &l);
4227 fprintf_filtered (stream, " DIE %s offset %s",
4228 phex_nz (ul, offset_size),
4233 case DW_OP_deref_type:
4234 case DW_OP_GNU_deref_type:
4236 int deref_addr_size = *data++;
4239 data = safe_read_uleb128 (data, end, &ul);
4240 cu_offset offset = (cu_offset) ul;
4241 type = dwarf2_get_die_type (offset, per_cu);
4242 fprintf_filtered (stream, "<");
4243 type_print (type, "", stream, -1);
4244 fprintf_filtered (stream, " [0x%s]> %d",
4245 phex_nz (to_underlying (offset), 0),
4250 case DW_OP_const_type:
4251 case DW_OP_GNU_const_type:
4255 data = safe_read_uleb128 (data, end, &ul);
4256 cu_offset type_die = (cu_offset) ul;
4257 type = dwarf2_get_die_type (type_die, per_cu);
4258 fprintf_filtered (stream, "<");
4259 type_print (type, "", stream, -1);
4260 fprintf_filtered (stream, " [0x%s]>",
4261 phex_nz (to_underlying (type_die), 0));
4265 case DW_OP_regval_type:
4266 case DW_OP_GNU_regval_type:
4271 data = safe_read_uleb128 (data, end, ®);
4272 data = safe_read_uleb128 (data, end, &ul);
4273 cu_offset type_die = (cu_offset) ul;
4275 type = dwarf2_get_die_type (type_die, per_cu);
4276 fprintf_filtered (stream, "<");
4277 type_print (type, "", stream, -1);
4278 fprintf_filtered (stream, " [0x%s]> [$%s]",
4279 phex_nz (to_underlying (type_die), 0),
4280 locexpr_regname (arch, reg));
4285 case DW_OP_GNU_convert:
4286 case DW_OP_reinterpret:
4287 case DW_OP_GNU_reinterpret:
4289 data = safe_read_uleb128 (data, end, &ul);
4290 cu_offset type_die = (cu_offset) ul;
4292 if (to_underlying (type_die) == 0)
4293 fprintf_filtered (stream, "<0>");
4298 type = dwarf2_get_die_type (type_die, per_cu);
4299 fprintf_filtered (stream, "<");
4300 type_print (type, "", stream, -1);
4301 fprintf_filtered (stream, " [0x%s]>",
4302 phex_nz (to_underlying (type_die), 0));
4307 case DW_OP_entry_value:
4308 case DW_OP_GNU_entry_value:
4309 data = safe_read_uleb128 (data, end, &ul);
4310 fputc_filtered ('\n', stream);
4311 disassemble_dwarf_expression (stream, arch, addr_size, offset_size,
4312 start, data, data + ul, indent + 2,
4317 case DW_OP_GNU_parameter_ref:
4318 ul = extract_unsigned_integer (data, 4, gdbarch_byte_order (arch));
4320 fprintf_filtered (stream, " offset %s", phex_nz (ul, 4));
4323 case DW_OP_GNU_addr_index:
4324 data = safe_read_uleb128 (data, end, &ul);
4325 ul = dwarf2_read_addr_index (per_cu, ul);
4326 fprintf_filtered (stream, " 0x%s", phex_nz (ul, addr_size));
4328 case DW_OP_GNU_const_index:
4329 data = safe_read_uleb128 (data, end, &ul);
4330 ul = dwarf2_read_addr_index (per_cu, ul);
4331 fprintf_filtered (stream, " %s", pulongest (ul));
4334 case DW_OP_GNU_variable_value:
4335 ul = extract_unsigned_integer (data, offset_size,
4336 gdbarch_byte_order (arch));
4337 data += offset_size;
4338 fprintf_filtered (stream, " offset %s", phex_nz (ul, offset_size));
4342 fprintf_filtered (stream, "\n");
4348 /* Describe a single location, which may in turn consist of multiple
4352 locexpr_describe_location_1 (struct symbol *symbol, CORE_ADDR addr,
4353 struct ui_file *stream,
4354 const gdb_byte *data, size_t size,
4355 struct objfile *objfile, unsigned int addr_size,
4356 int offset_size, struct dwarf2_per_cu_data *per_cu)
4358 const gdb_byte *end = data + size;
4359 int first_piece = 1, bad = 0;
4363 const gdb_byte *here = data;
4364 int disassemble = 1;
4369 fprintf_filtered (stream, _(", and "));
4371 if (!dwarf_always_disassemble)
4373 data = locexpr_describe_location_piece (symbol, stream,
4374 addr, objfile, per_cu,
4375 data, end, addr_size);
4376 /* If we printed anything, or if we have an empty piece,
4377 then don't disassemble. */
4379 || data[0] == DW_OP_piece
4380 || data[0] == DW_OP_bit_piece)
4385 fprintf_filtered (stream, _("a complex DWARF expression:\n"));
4386 data = disassemble_dwarf_expression (stream,
4387 get_objfile_arch (objfile),
4388 addr_size, offset_size, data,
4390 dwarf_always_disassemble,
4396 int empty = data == here;
4399 fprintf_filtered (stream, " ");
4400 if (data[0] == DW_OP_piece)
4404 data = safe_read_uleb128 (data + 1, end, &bytes);
4407 fprintf_filtered (stream, _("an empty %s-byte piece"),
4410 fprintf_filtered (stream, _(" [%s-byte piece]"),
4413 else if (data[0] == DW_OP_bit_piece)
4415 uint64_t bits, offset;
4417 data = safe_read_uleb128 (data + 1, end, &bits);
4418 data = safe_read_uleb128 (data, end, &offset);
4421 fprintf_filtered (stream,
4422 _("an empty %s-bit piece"),
4425 fprintf_filtered (stream,
4426 _(" [%s-bit piece, offset %s bits]"),
4427 pulongest (bits), pulongest (offset));
4437 if (bad || data > end)
4438 error (_("Corrupted DWARF2 expression for \"%s\"."),
4439 SYMBOL_PRINT_NAME (symbol));
4442 /* Print a natural-language description of SYMBOL to STREAM. This
4443 version is for a symbol with a single location. */
4446 locexpr_describe_location (struct symbol *symbol, CORE_ADDR addr,
4447 struct ui_file *stream)
4449 struct dwarf2_locexpr_baton *dlbaton
4450 = (struct dwarf2_locexpr_baton *) SYMBOL_LOCATION_BATON (symbol);
4451 struct objfile *objfile = dwarf2_per_cu_objfile (dlbaton->per_cu);
4452 unsigned int addr_size = dwarf2_per_cu_addr_size (dlbaton->per_cu);
4453 int offset_size = dwarf2_per_cu_offset_size (dlbaton->per_cu);
4455 locexpr_describe_location_1 (symbol, addr, stream,
4456 dlbaton->data, dlbaton->size,
4457 objfile, addr_size, offset_size,
4461 /* Describe the location of SYMBOL as an agent value in VALUE, generating
4462 any necessary bytecode in AX. */
4465 locexpr_tracepoint_var_ref (struct symbol *symbol, struct agent_expr *ax,
4466 struct axs_value *value)
4468 struct dwarf2_locexpr_baton *dlbaton
4469 = (struct dwarf2_locexpr_baton *) SYMBOL_LOCATION_BATON (symbol);
4470 unsigned int addr_size = dwarf2_per_cu_addr_size (dlbaton->per_cu);
4472 if (dlbaton->size == 0)
4473 value->optimized_out = 1;
4475 dwarf2_compile_expr_to_ax (ax, value, addr_size, dlbaton->data,
4476 dlbaton->data + dlbaton->size, dlbaton->per_cu);
4479 /* symbol_computed_ops 'generate_c_location' method. */
4482 locexpr_generate_c_location (struct symbol *sym, string_file *stream,
4483 struct gdbarch *gdbarch,
4484 unsigned char *registers_used,
4485 CORE_ADDR pc, const char *result_name)
4487 struct dwarf2_locexpr_baton *dlbaton
4488 = (struct dwarf2_locexpr_baton *) SYMBOL_LOCATION_BATON (sym);
4489 unsigned int addr_size = dwarf2_per_cu_addr_size (dlbaton->per_cu);
4491 if (dlbaton->size == 0)
4492 error (_("symbol \"%s\" is optimized out"), SYMBOL_NATURAL_NAME (sym));
4494 compile_dwarf_expr_to_c (stream, result_name,
4495 sym, pc, gdbarch, registers_used, addr_size,
4496 dlbaton->data, dlbaton->data + dlbaton->size,
4500 /* The set of location functions used with the DWARF-2 expression
4502 const struct symbol_computed_ops dwarf2_locexpr_funcs = {
4503 locexpr_read_variable,
4504 locexpr_read_variable_at_entry,
4505 locexpr_get_symbol_read_needs,
4506 locexpr_describe_location,
4507 0, /* location_has_loclist */
4508 locexpr_tracepoint_var_ref,
4509 locexpr_generate_c_location
4513 /* Wrapper functions for location lists. These generally find
4514 the appropriate location expression and call something above. */
4516 /* Return the value of SYMBOL in FRAME using the DWARF-2 expression
4517 evaluator to calculate the location. */
4518 static struct value *
4519 loclist_read_variable (struct symbol *symbol, struct frame_info *frame)
4521 struct dwarf2_loclist_baton *dlbaton
4522 = (struct dwarf2_loclist_baton *) SYMBOL_LOCATION_BATON (symbol);
4524 const gdb_byte *data;
4526 CORE_ADDR pc = frame ? get_frame_address_in_block (frame) : 0;
4528 data = dwarf2_find_location_expression (dlbaton, &size, pc);
4529 val = dwarf2_evaluate_loc_desc (SYMBOL_TYPE (symbol), frame, data, size,
4535 /* Read variable SYMBOL like loclist_read_variable at (callee) FRAME's function
4536 entry. SYMBOL should be a function parameter, otherwise NO_ENTRY_VALUE_ERROR
4539 Function always returns non-NULL value, it may be marked optimized out if
4540 inferior frame information is not available. It throws NO_ENTRY_VALUE_ERROR
4541 if it cannot resolve the parameter for any reason. */
4543 static struct value *
4544 loclist_read_variable_at_entry (struct symbol *symbol, struct frame_info *frame)
4546 struct dwarf2_loclist_baton *dlbaton
4547 = (struct dwarf2_loclist_baton *) SYMBOL_LOCATION_BATON (symbol);
4548 const gdb_byte *data;
4552 if (frame == NULL || !get_frame_func_if_available (frame, &pc))
4553 return allocate_optimized_out_value (SYMBOL_TYPE (symbol));
4555 data = dwarf2_find_location_expression (dlbaton, &size, pc);
4557 return allocate_optimized_out_value (SYMBOL_TYPE (symbol));
4559 return value_of_dwarf_block_entry (SYMBOL_TYPE (symbol), frame, data, size);
4562 /* Implementation of get_symbol_read_needs from
4563 symbol_computed_ops. */
4565 static enum symbol_needs_kind
4566 loclist_symbol_needs (struct symbol *symbol)
4568 /* If there's a location list, then assume we need to have a frame
4569 to choose the appropriate location expression. With tracking of
4570 global variables this is not necessarily true, but such tracking
4571 is disabled in GCC at the moment until we figure out how to
4574 return SYMBOL_NEEDS_FRAME;
4577 /* Print a natural-language description of SYMBOL to STREAM. This
4578 version applies when there is a list of different locations, each
4579 with a specified address range. */
4582 loclist_describe_location (struct symbol *symbol, CORE_ADDR addr,
4583 struct ui_file *stream)
4585 struct dwarf2_loclist_baton *dlbaton
4586 = (struct dwarf2_loclist_baton *) SYMBOL_LOCATION_BATON (symbol);
4587 const gdb_byte *loc_ptr, *buf_end;
4588 struct objfile *objfile = dwarf2_per_cu_objfile (dlbaton->per_cu);
4589 struct gdbarch *gdbarch = get_objfile_arch (objfile);
4590 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
4591 unsigned int addr_size = dwarf2_per_cu_addr_size (dlbaton->per_cu);
4592 int offset_size = dwarf2_per_cu_offset_size (dlbaton->per_cu);
4593 int signed_addr_p = bfd_get_sign_extend_vma (objfile->obfd);
4594 /* Adjust base_address for relocatable objects. */
4595 CORE_ADDR base_offset = dwarf2_per_cu_text_offset (dlbaton->per_cu);
4596 CORE_ADDR base_address = dlbaton->base_address + base_offset;
4599 loc_ptr = dlbaton->data;
4600 buf_end = dlbaton->data + dlbaton->size;
4602 fprintf_filtered (stream, _("multi-location:\n"));
4604 /* Iterate through locations until we run out. */
4607 CORE_ADDR low = 0, high = 0; /* init for gcc -Wall */
4609 enum debug_loc_kind kind;
4610 const gdb_byte *new_ptr = NULL; /* init for gcc -Wall */
4612 if (dlbaton->from_dwo)
4613 kind = decode_debug_loc_dwo_addresses (dlbaton->per_cu,
4614 loc_ptr, buf_end, &new_ptr,
4615 &low, &high, byte_order);
4617 kind = decode_debug_loc_addresses (loc_ptr, buf_end, &new_ptr,
4619 byte_order, addr_size,
4624 case DEBUG_LOC_END_OF_LIST:
4627 case DEBUG_LOC_BASE_ADDRESS:
4628 base_address = high + base_offset;
4629 fprintf_filtered (stream, _(" Base address %s"),
4630 paddress (gdbarch, base_address));
4632 case DEBUG_LOC_START_END:
4633 case DEBUG_LOC_START_LENGTH:
4635 case DEBUG_LOC_BUFFER_OVERFLOW:
4636 case DEBUG_LOC_INVALID_ENTRY:
4637 error (_("Corrupted DWARF expression for symbol \"%s\"."),
4638 SYMBOL_PRINT_NAME (symbol));
4640 gdb_assert_not_reached ("bad debug_loc_kind");
4643 /* Otherwise, a location expression entry. */
4644 low += base_address;
4645 high += base_address;
4647 low = gdbarch_adjust_dwarf2_addr (gdbarch, low);
4648 high = gdbarch_adjust_dwarf2_addr (gdbarch, high);
4650 length = extract_unsigned_integer (loc_ptr, 2, byte_order);
4653 /* (It would improve readability to print only the minimum
4654 necessary digits of the second number of the range.) */
4655 fprintf_filtered (stream, _(" Range %s-%s: "),
4656 paddress (gdbarch, low), paddress (gdbarch, high));
4658 /* Now describe this particular location. */
4659 locexpr_describe_location_1 (symbol, low, stream, loc_ptr, length,
4660 objfile, addr_size, offset_size,
4663 fprintf_filtered (stream, "\n");
4669 /* Describe the location of SYMBOL as an agent value in VALUE, generating
4670 any necessary bytecode in AX. */
4672 loclist_tracepoint_var_ref (struct symbol *symbol, struct agent_expr *ax,
4673 struct axs_value *value)
4675 struct dwarf2_loclist_baton *dlbaton
4676 = (struct dwarf2_loclist_baton *) SYMBOL_LOCATION_BATON (symbol);
4677 const gdb_byte *data;
4679 unsigned int addr_size = dwarf2_per_cu_addr_size (dlbaton->per_cu);
4681 data = dwarf2_find_location_expression (dlbaton, &size, ax->scope);
4683 value->optimized_out = 1;
4685 dwarf2_compile_expr_to_ax (ax, value, addr_size, data, data + size,
4689 /* symbol_computed_ops 'generate_c_location' method. */
4692 loclist_generate_c_location (struct symbol *sym, string_file *stream,
4693 struct gdbarch *gdbarch,
4694 unsigned char *registers_used,
4695 CORE_ADDR pc, const char *result_name)
4697 struct dwarf2_loclist_baton *dlbaton
4698 = (struct dwarf2_loclist_baton *) SYMBOL_LOCATION_BATON (sym);
4699 unsigned int addr_size = dwarf2_per_cu_addr_size (dlbaton->per_cu);
4700 const gdb_byte *data;
4703 data = dwarf2_find_location_expression (dlbaton, &size, pc);
4705 error (_("symbol \"%s\" is optimized out"), SYMBOL_NATURAL_NAME (sym));
4707 compile_dwarf_expr_to_c (stream, result_name,
4708 sym, pc, gdbarch, registers_used, addr_size,
4713 /* The set of location functions used with the DWARF-2 expression
4714 evaluator and location lists. */
4715 const struct symbol_computed_ops dwarf2_loclist_funcs = {
4716 loclist_read_variable,
4717 loclist_read_variable_at_entry,
4718 loclist_symbol_needs,
4719 loclist_describe_location,
4720 1, /* location_has_loclist */
4721 loclist_tracepoint_var_ref,
4722 loclist_generate_c_location
4726 _initialize_dwarf2loc (void)
4728 add_setshow_zuinteger_cmd ("entry-values", class_maintenance,
4729 &entry_values_debug,
4730 _("Set entry values and tail call frames "
4732 _("Show entry values and tail call frames "
4734 _("When non-zero, the process of determining "
4735 "parameter values from function entry point "
4736 "and tail call frames will be printed."),
4738 show_entry_values_debug,
4739 &setdebuglist, &showdebuglist);
4742 selftests::register_test ("copy_bitwise", selftests::copy_bitwise_tests);