1 /* DWARF 2 location expression support for GDB.
3 Copyright (C) 2003-2017 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"
47 extern int dwarf_always_disassemble;
49 static struct value *dwarf2_evaluate_loc_desc_full (struct type *type,
50 struct frame_info *frame,
53 struct dwarf2_per_cu_data *per_cu,
54 struct type *subobj_type,
55 LONGEST subobj_byte_offset);
57 static struct call_site_parameter *dwarf_expr_reg_to_entry_parameter
58 (struct frame_info *frame,
59 enum call_site_parameter_kind kind,
60 union call_site_parameter_u kind_u,
61 struct dwarf2_per_cu_data **per_cu_return);
63 /* Until these have formal names, we define these here.
64 ref: http://gcc.gnu.org/wiki/DebugFission
65 Each entry in .debug_loc.dwo begins with a byte that describes the entry,
66 and is then followed by data specific to that entry. */
70 /* Indicates the end of the list of entries. */
71 DEBUG_LOC_END_OF_LIST = 0,
73 /* This is followed by an unsigned LEB128 number that is an index into
74 .debug_addr and specifies the base address for all following entries. */
75 DEBUG_LOC_BASE_ADDRESS = 1,
77 /* This is followed by two unsigned LEB128 numbers that are indices into
78 .debug_addr and specify the beginning and ending addresses, and then
79 a normal location expression as in .debug_loc. */
80 DEBUG_LOC_START_END = 2,
82 /* This is followed by an unsigned LEB128 number that is an index into
83 .debug_addr and specifies the beginning address, and a 4 byte unsigned
84 number that specifies the length, and then a normal location expression
86 DEBUG_LOC_START_LENGTH = 3,
88 /* An internal value indicating there is insufficient data. */
89 DEBUG_LOC_BUFFER_OVERFLOW = -1,
91 /* An internal value indicating an invalid kind of entry was found. */
92 DEBUG_LOC_INVALID_ENTRY = -2
95 /* Helper function which throws an error if a synthetic pointer is
99 invalid_synthetic_pointer (void)
101 error (_("access outside bounds of object "
102 "referenced via synthetic pointer"));
105 /* Decode the addresses in a non-dwo .debug_loc entry.
106 A pointer to the next byte to examine is returned in *NEW_PTR.
107 The encoded low,high addresses are return in *LOW,*HIGH.
108 The result indicates the kind of entry found. */
110 static enum debug_loc_kind
111 decode_debug_loc_addresses (const gdb_byte *loc_ptr, const gdb_byte *buf_end,
112 const gdb_byte **new_ptr,
113 CORE_ADDR *low, CORE_ADDR *high,
114 enum bfd_endian byte_order,
115 unsigned int addr_size,
118 CORE_ADDR base_mask = ~(~(CORE_ADDR)1 << (addr_size * 8 - 1));
120 if (buf_end - loc_ptr < 2 * addr_size)
121 return DEBUG_LOC_BUFFER_OVERFLOW;
124 *low = extract_signed_integer (loc_ptr, addr_size, byte_order);
126 *low = extract_unsigned_integer (loc_ptr, addr_size, byte_order);
127 loc_ptr += addr_size;
130 *high = extract_signed_integer (loc_ptr, addr_size, byte_order);
132 *high = extract_unsigned_integer (loc_ptr, addr_size, byte_order);
133 loc_ptr += addr_size;
137 /* A base-address-selection entry. */
138 if ((*low & base_mask) == base_mask)
139 return DEBUG_LOC_BASE_ADDRESS;
141 /* An end-of-list entry. */
142 if (*low == 0 && *high == 0)
143 return DEBUG_LOC_END_OF_LIST;
145 return DEBUG_LOC_START_END;
148 /* Decode the addresses in .debug_loclists entry.
149 A pointer to the next byte to examine is returned in *NEW_PTR.
150 The encoded low,high addresses are return in *LOW,*HIGH.
151 The result indicates the kind of entry found. */
153 static enum debug_loc_kind
154 decode_debug_loclists_addresses (struct dwarf2_per_cu_data *per_cu,
155 const gdb_byte *loc_ptr,
156 const gdb_byte *buf_end,
157 const gdb_byte **new_ptr,
158 CORE_ADDR *low, CORE_ADDR *high,
159 enum bfd_endian byte_order,
160 unsigned int addr_size,
165 if (loc_ptr == buf_end)
166 return DEBUG_LOC_BUFFER_OVERFLOW;
170 case DW_LLE_end_of_list:
172 return DEBUG_LOC_END_OF_LIST;
173 case DW_LLE_base_address:
174 if (loc_ptr + addr_size > buf_end)
175 return DEBUG_LOC_BUFFER_OVERFLOW;
177 *high = extract_signed_integer (loc_ptr, addr_size, byte_order);
179 *high = extract_unsigned_integer (loc_ptr, addr_size, byte_order);
180 loc_ptr += addr_size;
182 return DEBUG_LOC_BASE_ADDRESS;
183 case DW_LLE_offset_pair:
184 loc_ptr = gdb_read_uleb128 (loc_ptr, buf_end, &u64);
186 return DEBUG_LOC_BUFFER_OVERFLOW;
188 loc_ptr = gdb_read_uleb128 (loc_ptr, buf_end, &u64);
190 return DEBUG_LOC_BUFFER_OVERFLOW;
193 return DEBUG_LOC_START_END;
195 return DEBUG_LOC_INVALID_ENTRY;
199 /* Decode the addresses in .debug_loc.dwo entry.
200 A pointer to the next byte to examine is returned in *NEW_PTR.
201 The encoded low,high addresses are return in *LOW,*HIGH.
202 The result indicates the kind of entry found. */
204 static enum debug_loc_kind
205 decode_debug_loc_dwo_addresses (struct dwarf2_per_cu_data *per_cu,
206 const gdb_byte *loc_ptr,
207 const gdb_byte *buf_end,
208 const gdb_byte **new_ptr,
209 CORE_ADDR *low, CORE_ADDR *high,
210 enum bfd_endian byte_order)
212 uint64_t low_index, high_index;
214 if (loc_ptr == buf_end)
215 return DEBUG_LOC_BUFFER_OVERFLOW;
219 case DW_LLE_GNU_end_of_list_entry:
221 return DEBUG_LOC_END_OF_LIST;
222 case DW_LLE_GNU_base_address_selection_entry:
224 loc_ptr = gdb_read_uleb128 (loc_ptr, buf_end, &high_index);
226 return DEBUG_LOC_BUFFER_OVERFLOW;
227 *high = dwarf2_read_addr_index (per_cu, high_index);
229 return DEBUG_LOC_BASE_ADDRESS;
230 case DW_LLE_GNU_start_end_entry:
231 loc_ptr = gdb_read_uleb128 (loc_ptr, buf_end, &low_index);
233 return DEBUG_LOC_BUFFER_OVERFLOW;
234 *low = dwarf2_read_addr_index (per_cu, low_index);
235 loc_ptr = gdb_read_uleb128 (loc_ptr, buf_end, &high_index);
237 return DEBUG_LOC_BUFFER_OVERFLOW;
238 *high = dwarf2_read_addr_index (per_cu, high_index);
240 return DEBUG_LOC_START_END;
241 case DW_LLE_GNU_start_length_entry:
242 loc_ptr = gdb_read_uleb128 (loc_ptr, buf_end, &low_index);
244 return DEBUG_LOC_BUFFER_OVERFLOW;
245 *low = dwarf2_read_addr_index (per_cu, low_index);
246 if (loc_ptr + 4 > buf_end)
247 return DEBUG_LOC_BUFFER_OVERFLOW;
249 *high += extract_unsigned_integer (loc_ptr, 4, byte_order);
250 *new_ptr = loc_ptr + 4;
251 return DEBUG_LOC_START_LENGTH;
253 return DEBUG_LOC_INVALID_ENTRY;
257 /* A function for dealing with location lists. Given a
258 symbol baton (BATON) and a pc value (PC), find the appropriate
259 location expression, set *LOCEXPR_LENGTH, and return a pointer
260 to the beginning of the expression. Returns NULL on failure.
262 For now, only return the first matching location expression; there
263 can be more than one in the list. */
266 dwarf2_find_location_expression (struct dwarf2_loclist_baton *baton,
267 size_t *locexpr_length, CORE_ADDR pc)
269 struct objfile *objfile = dwarf2_per_cu_objfile (baton->per_cu);
270 struct gdbarch *gdbarch = get_objfile_arch (objfile);
271 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
272 unsigned int addr_size = dwarf2_per_cu_addr_size (baton->per_cu);
273 int signed_addr_p = bfd_get_sign_extend_vma (objfile->obfd);
274 /* Adjust base_address for relocatable objects. */
275 CORE_ADDR base_offset = dwarf2_per_cu_text_offset (baton->per_cu);
276 CORE_ADDR base_address = baton->base_address + base_offset;
277 const gdb_byte *loc_ptr, *buf_end;
279 loc_ptr = baton->data;
280 buf_end = baton->data + baton->size;
284 CORE_ADDR low = 0, high = 0; /* init for gcc -Wall */
286 enum debug_loc_kind kind;
287 const gdb_byte *new_ptr = NULL; /* init for gcc -Wall */
290 kind = decode_debug_loc_dwo_addresses (baton->per_cu,
291 loc_ptr, buf_end, &new_ptr,
292 &low, &high, byte_order);
293 else if (dwarf2_version (baton->per_cu) < 5)
294 kind = decode_debug_loc_addresses (loc_ptr, buf_end, &new_ptr,
296 byte_order, addr_size,
299 kind = decode_debug_loclists_addresses (baton->per_cu,
300 loc_ptr, buf_end, &new_ptr,
301 &low, &high, byte_order,
302 addr_size, signed_addr_p);
307 case DEBUG_LOC_END_OF_LIST:
310 case DEBUG_LOC_BASE_ADDRESS:
311 base_address = high + base_offset;
313 case DEBUG_LOC_START_END:
314 case DEBUG_LOC_START_LENGTH:
316 case DEBUG_LOC_BUFFER_OVERFLOW:
317 case DEBUG_LOC_INVALID_ENTRY:
318 error (_("dwarf2_find_location_expression: "
319 "Corrupted DWARF expression."));
321 gdb_assert_not_reached ("bad debug_loc_kind");
324 /* Otherwise, a location expression entry.
325 If the entry is from a DWO, don't add base address: the entry is from
326 .debug_addr which already has the DWARF "base address". We still add
327 base_offset in case we're debugging a PIE executable. */
336 high += base_address;
339 if (dwarf2_version (baton->per_cu) < 5)
341 length = extract_unsigned_integer (loc_ptr, 2, byte_order);
346 unsigned int bytes_read;
348 length = read_unsigned_leb128 (NULL, loc_ptr, &bytes_read);
349 loc_ptr += bytes_read;
352 if (low == high && pc == low)
354 /* This is entry PC record present only at entry point
355 of a function. Verify it is really the function entry point. */
357 const struct block *pc_block = block_for_pc (pc);
358 struct symbol *pc_func = NULL;
361 pc_func = block_linkage_function (pc_block);
363 if (pc_func && pc == BLOCK_START (SYMBOL_BLOCK_VALUE (pc_func)))
365 *locexpr_length = length;
370 if (pc >= low && pc < high)
372 *locexpr_length = length;
380 /* This is the baton used when performing dwarf2 expression
382 struct dwarf_expr_baton
384 struct frame_info *frame;
385 struct dwarf2_per_cu_data *per_cu;
386 CORE_ADDR obj_address;
389 /* Implement find_frame_base_location method for LOC_BLOCK functions using
390 DWARF expression for its DW_AT_frame_base. */
393 locexpr_find_frame_base_location (struct symbol *framefunc, CORE_ADDR pc,
394 const gdb_byte **start, size_t *length)
396 struct dwarf2_locexpr_baton *symbaton
397 = (struct dwarf2_locexpr_baton *) SYMBOL_LOCATION_BATON (framefunc);
399 *length = symbaton->size;
400 *start = symbaton->data;
403 /* Implement the struct symbol_block_ops::get_frame_base method for
404 LOC_BLOCK functions using a DWARF expression as its DW_AT_frame_base. */
407 locexpr_get_frame_base (struct symbol *framefunc, struct frame_info *frame)
409 struct gdbarch *gdbarch;
411 struct dwarf2_locexpr_baton *dlbaton;
412 const gdb_byte *start;
414 struct value *result;
416 /* If this method is called, then FRAMEFUNC is supposed to be a DWARF block.
417 Thus, it's supposed to provide the find_frame_base_location method as
419 gdb_assert (SYMBOL_BLOCK_OPS (framefunc)->find_frame_base_location != NULL);
421 gdbarch = get_frame_arch (frame);
422 type = builtin_type (gdbarch)->builtin_data_ptr;
423 dlbaton = (struct dwarf2_locexpr_baton *) SYMBOL_LOCATION_BATON (framefunc);
425 SYMBOL_BLOCK_OPS (framefunc)->find_frame_base_location
426 (framefunc, get_frame_pc (frame), &start, &length);
427 result = dwarf2_evaluate_loc_desc (type, frame, start, length,
430 /* The DW_AT_frame_base attribute contains a location description which
431 computes the base address itself. However, the call to
432 dwarf2_evaluate_loc_desc returns a value representing a variable at
433 that address. The frame base address is thus this variable's
435 return value_address (result);
438 /* Vector for inferior functions as represented by LOC_BLOCK, if the inferior
439 function uses DWARF expression for its DW_AT_frame_base. */
441 const struct symbol_block_ops dwarf2_block_frame_base_locexpr_funcs =
443 locexpr_find_frame_base_location,
444 locexpr_get_frame_base
447 /* Implement find_frame_base_location method for LOC_BLOCK functions using
448 DWARF location list for its DW_AT_frame_base. */
451 loclist_find_frame_base_location (struct symbol *framefunc, CORE_ADDR pc,
452 const gdb_byte **start, size_t *length)
454 struct dwarf2_loclist_baton *symbaton
455 = (struct dwarf2_loclist_baton *) SYMBOL_LOCATION_BATON (framefunc);
457 *start = dwarf2_find_location_expression (symbaton, length, pc);
460 /* Implement the struct symbol_block_ops::get_frame_base method for
461 LOC_BLOCK functions using a DWARF location list as its DW_AT_frame_base. */
464 loclist_get_frame_base (struct symbol *framefunc, struct frame_info *frame)
466 struct gdbarch *gdbarch;
468 struct dwarf2_loclist_baton *dlbaton;
469 const gdb_byte *start;
471 struct value *result;
473 /* If this method is called, then FRAMEFUNC is supposed to be a DWARF block.
474 Thus, it's supposed to provide the find_frame_base_location method as
476 gdb_assert (SYMBOL_BLOCK_OPS (framefunc)->find_frame_base_location != NULL);
478 gdbarch = get_frame_arch (frame);
479 type = builtin_type (gdbarch)->builtin_data_ptr;
480 dlbaton = (struct dwarf2_loclist_baton *) SYMBOL_LOCATION_BATON (framefunc);
482 SYMBOL_BLOCK_OPS (framefunc)->find_frame_base_location
483 (framefunc, get_frame_pc (frame), &start, &length);
484 result = dwarf2_evaluate_loc_desc (type, frame, start, length,
487 /* The DW_AT_frame_base attribute contains a location description which
488 computes the base address itself. However, the call to
489 dwarf2_evaluate_loc_desc returns a value representing a variable at
490 that address. The frame base address is thus this variable's
492 return value_address (result);
495 /* Vector for inferior functions as represented by LOC_BLOCK, if the inferior
496 function uses DWARF location list for its DW_AT_frame_base. */
498 const struct symbol_block_ops dwarf2_block_frame_base_loclist_funcs =
500 loclist_find_frame_base_location,
501 loclist_get_frame_base
504 /* See dwarf2loc.h. */
507 func_get_frame_base_dwarf_block (struct symbol *framefunc, CORE_ADDR pc,
508 const gdb_byte **start, size_t *length)
510 if (SYMBOL_BLOCK_OPS (framefunc) != NULL)
512 const struct symbol_block_ops *ops_block = SYMBOL_BLOCK_OPS (framefunc);
514 ops_block->find_frame_base_location (framefunc, pc, start, length);
520 error (_("Could not find the frame base for \"%s\"."),
521 SYMBOL_NATURAL_NAME (framefunc));
525 get_frame_pc_for_per_cu_dwarf_call (void *baton)
527 dwarf_expr_context *ctx = (dwarf_expr_context *) baton;
529 return ctx->get_frame_pc ();
533 per_cu_dwarf_call (struct dwarf_expr_context *ctx, cu_offset die_offset,
534 struct dwarf2_per_cu_data *per_cu)
536 struct dwarf2_locexpr_baton block;
538 block = dwarf2_fetch_die_loc_cu_off (die_offset, per_cu,
539 get_frame_pc_for_per_cu_dwarf_call,
542 /* DW_OP_call_ref is currently not supported. */
543 gdb_assert (block.per_cu == per_cu);
545 ctx->eval (block.data, block.size);
548 class dwarf_evaluate_loc_desc : public dwarf_expr_context
552 struct frame_info *frame;
553 struct dwarf2_per_cu_data *per_cu;
554 CORE_ADDR obj_address;
556 /* Helper function for dwarf2_evaluate_loc_desc. Computes the CFA for
557 the frame in BATON. */
559 CORE_ADDR get_frame_cfa () OVERRIDE
561 return dwarf2_frame_cfa (frame);
564 /* Helper function for dwarf2_evaluate_loc_desc. Computes the PC for
565 the frame in BATON. */
567 CORE_ADDR get_frame_pc () OVERRIDE
569 return get_frame_address_in_block (frame);
572 /* Using the objfile specified in BATON, find the address for the
573 current thread's thread-local storage with offset OFFSET. */
574 CORE_ADDR get_tls_address (CORE_ADDR offset) OVERRIDE
576 struct objfile *objfile = dwarf2_per_cu_objfile (per_cu);
578 return target_translate_tls_address (objfile, offset);
581 /* Helper interface of per_cu_dwarf_call for
582 dwarf2_evaluate_loc_desc. */
584 void dwarf_call (cu_offset die_offset) OVERRIDE
586 per_cu_dwarf_call (this, die_offset, per_cu);
589 struct type *get_base_type (cu_offset die_offset, int size) OVERRIDE
591 struct type *result = dwarf2_get_die_type (die_offset, per_cu);
593 error (_("Could not find type for DW_OP_const_type"));
594 if (size != 0 && TYPE_LENGTH (result) != size)
595 error (_("DW_OP_const_type has different sizes for type and data"));
599 /* Callback function for dwarf2_evaluate_loc_desc.
600 Fetch the address indexed by DW_OP_GNU_addr_index. */
602 CORE_ADDR get_addr_index (unsigned int index) OVERRIDE
604 return dwarf2_read_addr_index (per_cu, index);
607 /* Callback function for get_object_address. Return the address of the VLA
610 CORE_ADDR get_object_address () OVERRIDE
612 if (obj_address == 0)
613 error (_("Location address is not set."));
617 /* Execute DWARF block of call_site_parameter which matches KIND and
618 KIND_U. Choose DEREF_SIZE value of that parameter. Search
619 caller of this objects's frame.
621 The caller can be from a different CU - per_cu_dwarf_call
622 implementation can be more simple as it does not support cross-CU
625 void push_dwarf_reg_entry_value (enum call_site_parameter_kind kind,
626 union call_site_parameter_u kind_u,
627 int deref_size) OVERRIDE
629 struct frame_info *caller_frame;
630 struct dwarf2_per_cu_data *caller_per_cu;
631 struct call_site_parameter *parameter;
632 const gdb_byte *data_src;
635 caller_frame = get_prev_frame (frame);
637 parameter = dwarf_expr_reg_to_entry_parameter (frame, kind, kind_u,
639 data_src = deref_size == -1 ? parameter->value : parameter->data_value;
640 size = deref_size == -1 ? parameter->value_size : parameter->data_value_size;
642 /* DEREF_SIZE size is not verified here. */
643 if (data_src == NULL)
644 throw_error (NO_ENTRY_VALUE_ERROR,
645 _("Cannot resolve DW_AT_call_data_value"));
647 scoped_restore save_frame = make_scoped_restore (&this->frame,
649 scoped_restore save_per_cu = make_scoped_restore (&this->per_cu,
651 scoped_restore save_obj_addr = make_scoped_restore (&this->obj_address,
654 scoped_restore save_arch = make_scoped_restore (&this->gdbarch);
656 = get_objfile_arch (dwarf2_per_cu_objfile (per_cu));
657 scoped_restore save_addr_size = make_scoped_restore (&this->addr_size);
658 this->addr_size = dwarf2_per_cu_addr_size (per_cu);
659 scoped_restore save_offset = make_scoped_restore (&this->offset);
660 this->offset = dwarf2_per_cu_text_offset (per_cu);
662 this->eval (data_src, size);
665 /* Using the frame specified in BATON, find the location expression
666 describing the frame base. Return a pointer to it in START and
667 its length in LENGTH. */
668 void get_frame_base (const gdb_byte **start, size_t * length) OVERRIDE
670 /* FIXME: cagney/2003-03-26: This code should be using
671 get_frame_base_address(), and then implement a dwarf2 specific
673 struct symbol *framefunc;
674 const struct block *bl = get_frame_block (frame, NULL);
677 error (_("frame address is not available."));
679 /* Use block_linkage_function, which returns a real (not inlined)
680 function, instead of get_frame_function, which may return an
682 framefunc = block_linkage_function (bl);
684 /* If we found a frame-relative symbol then it was certainly within
685 some function associated with a frame. If we can't find the frame,
686 something has gone wrong. */
687 gdb_assert (framefunc != NULL);
689 func_get_frame_base_dwarf_block (framefunc,
690 get_frame_address_in_block (frame),
694 /* Read memory at ADDR (length LEN) into BUF. */
696 void read_mem (gdb_byte *buf, CORE_ADDR addr, size_t len) OVERRIDE
698 read_memory (addr, buf, len);
701 /* Using the frame specified in BATON, return the value of register
702 REGNUM, treated as a pointer. */
703 CORE_ADDR read_addr_from_reg (int dwarf_regnum) OVERRIDE
705 struct gdbarch *gdbarch = get_frame_arch (frame);
706 int regnum = dwarf_reg_to_regnum_or_error (gdbarch, dwarf_regnum);
708 return address_from_register (regnum, frame);
711 /* Implement "get_reg_value" callback. */
713 struct value *get_reg_value (struct type *type, int dwarf_regnum) OVERRIDE
715 struct gdbarch *gdbarch = get_frame_arch (frame);
716 int regnum = dwarf_reg_to_regnum_or_error (gdbarch, dwarf_regnum);
718 return value_from_register (type, regnum, frame);
722 /* See dwarf2loc.h. */
724 unsigned int entry_values_debug = 0;
726 /* Helper to set entry_values_debug. */
729 show_entry_values_debug (struct ui_file *file, int from_tty,
730 struct cmd_list_element *c, const char *value)
732 fprintf_filtered (file,
733 _("Entry values and tail call frames debugging is %s.\n"),
737 /* Find DW_TAG_call_site's DW_AT_call_target address.
738 CALLER_FRAME (for registers) can be NULL if it is not known. This function
739 always returns valid address or it throws NO_ENTRY_VALUE_ERROR. */
742 call_site_to_target_addr (struct gdbarch *call_site_gdbarch,
743 struct call_site *call_site,
744 struct frame_info *caller_frame)
746 switch (FIELD_LOC_KIND (call_site->target))
748 case FIELD_LOC_KIND_DWARF_BLOCK:
750 struct dwarf2_locexpr_baton *dwarf_block;
752 struct type *caller_core_addr_type;
753 struct gdbarch *caller_arch;
755 dwarf_block = FIELD_DWARF_BLOCK (call_site->target);
756 if (dwarf_block == NULL)
758 struct bound_minimal_symbol msym;
760 msym = lookup_minimal_symbol_by_pc (call_site->pc - 1);
761 throw_error (NO_ENTRY_VALUE_ERROR,
762 _("DW_AT_call_target is not specified at %s in %s"),
763 paddress (call_site_gdbarch, call_site->pc),
764 (msym.minsym == NULL ? "???"
765 : MSYMBOL_PRINT_NAME (msym.minsym)));
768 if (caller_frame == NULL)
770 struct bound_minimal_symbol msym;
772 msym = lookup_minimal_symbol_by_pc (call_site->pc - 1);
773 throw_error (NO_ENTRY_VALUE_ERROR,
774 _("DW_AT_call_target DWARF block resolving "
775 "requires known frame which is currently not "
776 "available at %s in %s"),
777 paddress (call_site_gdbarch, call_site->pc),
778 (msym.minsym == NULL ? "???"
779 : MSYMBOL_PRINT_NAME (msym.minsym)));
782 caller_arch = get_frame_arch (caller_frame);
783 caller_core_addr_type = builtin_type (caller_arch)->builtin_func_ptr;
784 val = dwarf2_evaluate_loc_desc (caller_core_addr_type, caller_frame,
785 dwarf_block->data, dwarf_block->size,
786 dwarf_block->per_cu);
787 /* DW_AT_call_target is a DWARF expression, not a DWARF location. */
788 if (VALUE_LVAL (val) == lval_memory)
789 return value_address (val);
791 return value_as_address (val);
794 case FIELD_LOC_KIND_PHYSNAME:
796 const char *physname;
797 struct bound_minimal_symbol msym;
799 physname = FIELD_STATIC_PHYSNAME (call_site->target);
801 /* Handle both the mangled and demangled PHYSNAME. */
802 msym = lookup_minimal_symbol (physname, NULL, NULL);
803 if (msym.minsym == NULL)
805 msym = lookup_minimal_symbol_by_pc (call_site->pc - 1);
806 throw_error (NO_ENTRY_VALUE_ERROR,
807 _("Cannot find function \"%s\" for a call site target "
809 physname, paddress (call_site_gdbarch, call_site->pc),
810 (msym.minsym == NULL ? "???"
811 : MSYMBOL_PRINT_NAME (msym.minsym)));
814 return BMSYMBOL_VALUE_ADDRESS (msym);
817 case FIELD_LOC_KIND_PHYSADDR:
818 return FIELD_STATIC_PHYSADDR (call_site->target);
821 internal_error (__FILE__, __LINE__, _("invalid call site target kind"));
825 /* Convert function entry point exact address ADDR to the function which is
826 compliant with TAIL_CALL_LIST_COMPLETE condition. Throw
827 NO_ENTRY_VALUE_ERROR otherwise. */
829 static struct symbol *
830 func_addr_to_tail_call_list (struct gdbarch *gdbarch, CORE_ADDR addr)
832 struct symbol *sym = find_pc_function (addr);
835 if (sym == NULL || BLOCK_START (SYMBOL_BLOCK_VALUE (sym)) != addr)
836 throw_error (NO_ENTRY_VALUE_ERROR,
837 _("DW_TAG_call_site resolving failed to find function "
838 "name for address %s"),
839 paddress (gdbarch, addr));
841 type = SYMBOL_TYPE (sym);
842 gdb_assert (TYPE_CODE (type) == TYPE_CODE_FUNC);
843 gdb_assert (TYPE_SPECIFIC_FIELD (type) == TYPE_SPECIFIC_FUNC);
848 /* Verify function with entry point exact address ADDR can never call itself
849 via its tail calls (incl. transitively). Throw NO_ENTRY_VALUE_ERROR if it
850 can call itself via tail calls.
852 If a funtion can tail call itself its entry value based parameters are
853 unreliable. There is no verification whether the value of some/all
854 parameters is unchanged through the self tail call, we expect if there is
855 a self tail call all the parameters can be modified. */
858 func_verify_no_selftailcall (struct gdbarch *gdbarch, CORE_ADDR verify_addr)
862 /* The verification is completely unordered. Track here function addresses
863 which still need to be iterated. */
864 std::vector<CORE_ADDR> todo;
866 /* Track here CORE_ADDRs which were already visited. */
867 std::unordered_set<CORE_ADDR> addr_hash;
869 todo.push_back (verify_addr);
870 while (!todo.empty ())
872 struct symbol *func_sym;
873 struct call_site *call_site;
878 func_sym = func_addr_to_tail_call_list (gdbarch, addr);
880 for (call_site = TYPE_TAIL_CALL_LIST (SYMBOL_TYPE (func_sym));
881 call_site; call_site = call_site->tail_call_next)
883 CORE_ADDR target_addr;
885 /* CALLER_FRAME with registers is not available for tail-call jumped
887 target_addr = call_site_to_target_addr (gdbarch, call_site, NULL);
889 if (target_addr == verify_addr)
891 struct bound_minimal_symbol msym;
893 msym = lookup_minimal_symbol_by_pc (verify_addr);
894 throw_error (NO_ENTRY_VALUE_ERROR,
895 _("DW_OP_entry_value resolving has found "
896 "function \"%s\" at %s can call itself via tail "
898 (msym.minsym == NULL ? "???"
899 : MSYMBOL_PRINT_NAME (msym.minsym)),
900 paddress (gdbarch, verify_addr));
903 if (addr_hash.insert (target_addr).second)
904 todo.push_back (target_addr);
909 /* Print user readable form of CALL_SITE->PC to gdb_stdlog. Used only for
910 ENTRY_VALUES_DEBUG. */
913 tailcall_dump (struct gdbarch *gdbarch, const struct call_site *call_site)
915 CORE_ADDR addr = call_site->pc;
916 struct bound_minimal_symbol msym = lookup_minimal_symbol_by_pc (addr - 1);
918 fprintf_unfiltered (gdb_stdlog, " %s(%s)", paddress (gdbarch, addr),
919 (msym.minsym == NULL ? "???"
920 : MSYMBOL_PRINT_NAME (msym.minsym)));
924 /* Intersect RESULTP with CHAIN to keep RESULTP unambiguous, keep in RESULTP
925 only top callers and bottom callees which are present in both. GDBARCH is
926 used only for ENTRY_VALUES_DEBUG. RESULTP is NULL after return if there are
927 no remaining possibilities to provide unambiguous non-trivial result.
928 RESULTP should point to NULL on the first (initialization) call. Caller is
929 responsible for xfree of any RESULTP data. */
932 chain_candidate (struct gdbarch *gdbarch,
933 gdb::unique_xmalloc_ptr<struct call_site_chain> *resultp,
934 std::vector<struct call_site *> *chain)
936 long length = chain->size ();
937 int callers, callees, idx;
939 if (*resultp == NULL)
941 /* Create the initial chain containing all the passed PCs. */
943 struct call_site_chain *result
944 = ((struct call_site_chain *)
945 xmalloc (sizeof (*result)
946 + sizeof (*result->call_site) * (length - 1)));
947 result->length = length;
948 result->callers = result->callees = length;
949 if (!chain->empty ())
950 memcpy (result->call_site, chain->data (),
951 sizeof (*result->call_site) * length);
952 resultp->reset (result);
954 if (entry_values_debug)
956 fprintf_unfiltered (gdb_stdlog, "tailcall: initial:");
957 for (idx = 0; idx < length; idx++)
958 tailcall_dump (gdbarch, result->call_site[idx]);
959 fputc_unfiltered ('\n', gdb_stdlog);
965 if (entry_values_debug)
967 fprintf_unfiltered (gdb_stdlog, "tailcall: compare:");
968 for (idx = 0; idx < length; idx++)
969 tailcall_dump (gdbarch, chain->at (idx));
970 fputc_unfiltered ('\n', gdb_stdlog);
973 /* Intersect callers. */
975 callers = std::min ((long) (*resultp)->callers, length);
976 for (idx = 0; idx < callers; idx++)
977 if ((*resultp)->call_site[idx] != chain->at (idx))
979 (*resultp)->callers = idx;
983 /* Intersect callees. */
985 callees = std::min ((long) (*resultp)->callees, length);
986 for (idx = 0; idx < callees; idx++)
987 if ((*resultp)->call_site[(*resultp)->length - 1 - idx]
988 != chain->at (length - 1 - idx))
990 (*resultp)->callees = idx;
994 if (entry_values_debug)
996 fprintf_unfiltered (gdb_stdlog, "tailcall: reduced:");
997 for (idx = 0; idx < (*resultp)->callers; idx++)
998 tailcall_dump (gdbarch, (*resultp)->call_site[idx]);
999 fputs_unfiltered (" |", gdb_stdlog);
1000 for (idx = 0; idx < (*resultp)->callees; idx++)
1001 tailcall_dump (gdbarch,
1002 (*resultp)->call_site[(*resultp)->length
1003 - (*resultp)->callees + idx]);
1004 fputc_unfiltered ('\n', gdb_stdlog);
1007 if ((*resultp)->callers == 0 && (*resultp)->callees == 0)
1009 /* There are no common callers or callees. It could be also a direct
1010 call (which has length 0) with ambiguous possibility of an indirect
1011 call - CALLERS == CALLEES == 0 is valid during the first allocation
1012 but any subsequence processing of such entry means ambiguity. */
1013 resultp->reset (NULL);
1017 /* See call_site_find_chain_1 why there is no way to reach the bottom callee
1018 PC again. In such case there must be two different code paths to reach
1019 it. CALLERS + CALLEES equal to LENGTH in the case of self tail-call. */
1020 gdb_assert ((*resultp)->callers + (*resultp)->callees <= (*resultp)->length);
1023 /* Create and return call_site_chain for CALLER_PC and CALLEE_PC. All the
1024 assumed frames between them use GDBARCH. Use depth first search so we can
1025 keep single CHAIN of call_site's back to CALLER_PC. Function recursion
1026 would have needless GDB stack overhead. Caller is responsible for xfree of
1027 the returned result. Any unreliability results in thrown
1028 NO_ENTRY_VALUE_ERROR. */
1030 static struct call_site_chain *
1031 call_site_find_chain_1 (struct gdbarch *gdbarch, CORE_ADDR caller_pc,
1032 CORE_ADDR callee_pc)
1034 CORE_ADDR save_callee_pc = callee_pc;
1035 gdb::unique_xmalloc_ptr<struct call_site_chain> retval;
1036 struct call_site *call_site;
1038 /* CHAIN contains only the intermediate CALL_SITEs. Neither CALLER_PC's
1039 call_site nor any possible call_site at CALLEE_PC's function is there.
1040 Any CALL_SITE in CHAIN will be iterated to its siblings - via
1041 TAIL_CALL_NEXT. This is inappropriate for CALLER_PC's call_site. */
1042 std::vector<struct call_site *> chain;
1044 /* We are not interested in the specific PC inside the callee function. */
1045 callee_pc = get_pc_function_start (callee_pc);
1047 throw_error (NO_ENTRY_VALUE_ERROR, _("Unable to find function for PC %s"),
1048 paddress (gdbarch, save_callee_pc));
1050 /* Mark CALL_SITEs so we do not visit the same ones twice. */
1051 std::unordered_set<CORE_ADDR> addr_hash;
1053 /* Do not push CALL_SITE to CHAIN. Push there only the first tail call site
1054 at the target's function. All the possible tail call sites in the
1055 target's function will get iterated as already pushed into CHAIN via their
1057 call_site = call_site_for_pc (gdbarch, caller_pc);
1061 CORE_ADDR target_func_addr;
1062 struct call_site *target_call_site;
1064 /* CALLER_FRAME with registers is not available for tail-call jumped
1066 target_func_addr = call_site_to_target_addr (gdbarch, call_site, NULL);
1068 if (target_func_addr == callee_pc)
1070 chain_candidate (gdbarch, &retval, &chain);
1074 /* There is no way to reach CALLEE_PC again as we would prevent
1075 entering it twice as being already marked in ADDR_HASH. */
1076 target_call_site = NULL;
1080 struct symbol *target_func;
1082 target_func = func_addr_to_tail_call_list (gdbarch, target_func_addr);
1083 target_call_site = TYPE_TAIL_CALL_LIST (SYMBOL_TYPE (target_func));
1088 /* Attempt to visit TARGET_CALL_SITE. */
1090 if (target_call_site)
1092 if (addr_hash.insert (target_call_site->pc).second)
1094 /* Successfully entered TARGET_CALL_SITE. */
1096 chain.push_back (target_call_site);
1101 /* Backtrack (without revisiting the originating call_site). Try the
1102 callers's sibling; if there isn't any try the callers's callers's
1105 target_call_site = NULL;
1106 while (!chain.empty ())
1108 call_site = chain.back ();
1111 size_t removed = addr_hash.erase (call_site->pc);
1112 gdb_assert (removed == 1);
1114 target_call_site = call_site->tail_call_next;
1115 if (target_call_site)
1119 while (target_call_site);
1124 call_site = chain.back ();
1129 struct bound_minimal_symbol msym_caller, msym_callee;
1131 msym_caller = lookup_minimal_symbol_by_pc (caller_pc);
1132 msym_callee = lookup_minimal_symbol_by_pc (callee_pc);
1133 throw_error (NO_ENTRY_VALUE_ERROR,
1134 _("There are no unambiguously determinable intermediate "
1135 "callers or callees between caller function \"%s\" at %s "
1136 "and callee function \"%s\" at %s"),
1137 (msym_caller.minsym == NULL
1138 ? "???" : MSYMBOL_PRINT_NAME (msym_caller.minsym)),
1139 paddress (gdbarch, caller_pc),
1140 (msym_callee.minsym == NULL
1141 ? "???" : MSYMBOL_PRINT_NAME (msym_callee.minsym)),
1142 paddress (gdbarch, callee_pc));
1145 return retval.release ();
1148 /* Create and return call_site_chain for CALLER_PC and CALLEE_PC. All the
1149 assumed frames between them use GDBARCH. If valid call_site_chain cannot be
1150 constructed return NULL. Caller is responsible for xfree of the returned
1153 struct call_site_chain *
1154 call_site_find_chain (struct gdbarch *gdbarch, CORE_ADDR caller_pc,
1155 CORE_ADDR callee_pc)
1157 struct call_site_chain *retval = NULL;
1161 retval = call_site_find_chain_1 (gdbarch, caller_pc, callee_pc);
1163 CATCH (e, RETURN_MASK_ERROR)
1165 if (e.error == NO_ENTRY_VALUE_ERROR)
1167 if (entry_values_debug)
1168 exception_print (gdb_stdout, e);
1173 throw_exception (e);
1180 /* Return 1 if KIND and KIND_U match PARAMETER. Return 0 otherwise. */
1183 call_site_parameter_matches (struct call_site_parameter *parameter,
1184 enum call_site_parameter_kind kind,
1185 union call_site_parameter_u kind_u)
1187 if (kind == parameter->kind)
1190 case CALL_SITE_PARAMETER_DWARF_REG:
1191 return kind_u.dwarf_reg == parameter->u.dwarf_reg;
1192 case CALL_SITE_PARAMETER_FB_OFFSET:
1193 return kind_u.fb_offset == parameter->u.fb_offset;
1194 case CALL_SITE_PARAMETER_PARAM_OFFSET:
1195 return kind_u.param_cu_off == parameter->u.param_cu_off;
1200 /* Fetch call_site_parameter from caller matching KIND and KIND_U.
1201 FRAME is for callee.
1203 Function always returns non-NULL, it throws NO_ENTRY_VALUE_ERROR
1206 static struct call_site_parameter *
1207 dwarf_expr_reg_to_entry_parameter (struct frame_info *frame,
1208 enum call_site_parameter_kind kind,
1209 union call_site_parameter_u kind_u,
1210 struct dwarf2_per_cu_data **per_cu_return)
1212 CORE_ADDR func_addr, caller_pc;
1213 struct gdbarch *gdbarch;
1214 struct frame_info *caller_frame;
1215 struct call_site *call_site;
1217 /* Initialize it just to avoid a GCC false warning. */
1218 struct call_site_parameter *parameter = NULL;
1219 CORE_ADDR target_addr;
1221 while (get_frame_type (frame) == INLINE_FRAME)
1223 frame = get_prev_frame (frame);
1224 gdb_assert (frame != NULL);
1227 func_addr = get_frame_func (frame);
1228 gdbarch = get_frame_arch (frame);
1229 caller_frame = get_prev_frame (frame);
1230 if (gdbarch != frame_unwind_arch (frame))
1232 struct bound_minimal_symbol msym
1233 = lookup_minimal_symbol_by_pc (func_addr);
1234 struct gdbarch *caller_gdbarch = frame_unwind_arch (frame);
1236 throw_error (NO_ENTRY_VALUE_ERROR,
1237 _("DW_OP_entry_value resolving callee gdbarch %s "
1238 "(of %s (%s)) does not match caller gdbarch %s"),
1239 gdbarch_bfd_arch_info (gdbarch)->printable_name,
1240 paddress (gdbarch, func_addr),
1241 (msym.minsym == NULL ? "???"
1242 : MSYMBOL_PRINT_NAME (msym.minsym)),
1243 gdbarch_bfd_arch_info (caller_gdbarch)->printable_name);
1246 if (caller_frame == NULL)
1248 struct bound_minimal_symbol msym
1249 = lookup_minimal_symbol_by_pc (func_addr);
1251 throw_error (NO_ENTRY_VALUE_ERROR, _("DW_OP_entry_value resolving "
1252 "requires caller of %s (%s)"),
1253 paddress (gdbarch, func_addr),
1254 (msym.minsym == NULL ? "???"
1255 : MSYMBOL_PRINT_NAME (msym.minsym)));
1257 caller_pc = get_frame_pc (caller_frame);
1258 call_site = call_site_for_pc (gdbarch, caller_pc);
1260 target_addr = call_site_to_target_addr (gdbarch, call_site, caller_frame);
1261 if (target_addr != func_addr)
1263 struct minimal_symbol *target_msym, *func_msym;
1265 target_msym = lookup_minimal_symbol_by_pc (target_addr).minsym;
1266 func_msym = lookup_minimal_symbol_by_pc (func_addr).minsym;
1267 throw_error (NO_ENTRY_VALUE_ERROR,
1268 _("DW_OP_entry_value resolving expects callee %s at %s "
1269 "but the called frame is for %s at %s"),
1270 (target_msym == NULL ? "???"
1271 : MSYMBOL_PRINT_NAME (target_msym)),
1272 paddress (gdbarch, target_addr),
1273 func_msym == NULL ? "???" : MSYMBOL_PRINT_NAME (func_msym),
1274 paddress (gdbarch, func_addr));
1277 /* No entry value based parameters would be reliable if this function can
1278 call itself via tail calls. */
1279 func_verify_no_selftailcall (gdbarch, func_addr);
1281 for (iparams = 0; iparams < call_site->parameter_count; iparams++)
1283 parameter = &call_site->parameter[iparams];
1284 if (call_site_parameter_matches (parameter, kind, kind_u))
1287 if (iparams == call_site->parameter_count)
1289 struct minimal_symbol *msym
1290 = lookup_minimal_symbol_by_pc (caller_pc).minsym;
1292 /* DW_TAG_call_site_parameter will be missing just if GCC could not
1293 determine its value. */
1294 throw_error (NO_ENTRY_VALUE_ERROR, _("Cannot find matching parameter "
1295 "at DW_TAG_call_site %s at %s"),
1296 paddress (gdbarch, caller_pc),
1297 msym == NULL ? "???" : MSYMBOL_PRINT_NAME (msym));
1300 *per_cu_return = call_site->per_cu;
1304 /* Return value for PARAMETER matching DEREF_SIZE. If DEREF_SIZE is -1, return
1305 the normal DW_AT_call_value block. Otherwise return the
1306 DW_AT_call_data_value (dereferenced) block.
1308 TYPE and CALLER_FRAME specify how to evaluate the DWARF block into returned
1311 Function always returns non-NULL, non-optimized out value. It throws
1312 NO_ENTRY_VALUE_ERROR if it cannot resolve the value for any reason. */
1314 static struct value *
1315 dwarf_entry_parameter_to_value (struct call_site_parameter *parameter,
1316 CORE_ADDR deref_size, struct type *type,
1317 struct frame_info *caller_frame,
1318 struct dwarf2_per_cu_data *per_cu)
1320 const gdb_byte *data_src;
1324 data_src = deref_size == -1 ? parameter->value : parameter->data_value;
1325 size = deref_size == -1 ? parameter->value_size : parameter->data_value_size;
1327 /* DEREF_SIZE size is not verified here. */
1328 if (data_src == NULL)
1329 throw_error (NO_ENTRY_VALUE_ERROR,
1330 _("Cannot resolve DW_AT_call_data_value"));
1332 /* DW_AT_call_value is a DWARF expression, not a DWARF
1333 location. Postprocessing of DWARF_VALUE_MEMORY would lose the type from
1335 data = (gdb_byte *) alloca (size + 1);
1336 memcpy (data, data_src, size);
1337 data[size] = DW_OP_stack_value;
1339 return dwarf2_evaluate_loc_desc (type, caller_frame, data, size + 1, per_cu);
1342 /* VALUE must be of type lval_computed with entry_data_value_funcs. Perform
1343 the indirect method on it, that is use its stored target value, the sole
1344 purpose of entry_data_value_funcs.. */
1346 static struct value *
1347 entry_data_value_coerce_ref (const struct value *value)
1349 struct type *checked_type = check_typedef (value_type (value));
1350 struct value *target_val;
1352 if (!TYPE_IS_REFERENCE (checked_type))
1355 target_val = (struct value *) value_computed_closure (value);
1356 value_incref (target_val);
1360 /* Implement copy_closure. */
1363 entry_data_value_copy_closure (const struct value *v)
1365 struct value *target_val = (struct value *) value_computed_closure (v);
1367 value_incref (target_val);
1371 /* Implement free_closure. */
1374 entry_data_value_free_closure (struct value *v)
1376 struct value *target_val = (struct value *) value_computed_closure (v);
1378 value_free (target_val);
1381 /* Vector for methods for an entry value reference where the referenced value
1382 is stored in the caller. On the first dereference use
1383 DW_AT_call_data_value in the caller. */
1385 static const struct lval_funcs entry_data_value_funcs =
1389 NULL, /* indirect */
1390 entry_data_value_coerce_ref,
1391 NULL, /* check_synthetic_pointer */
1392 entry_data_value_copy_closure,
1393 entry_data_value_free_closure
1396 /* Read parameter of TYPE at (callee) FRAME's function entry. KIND and KIND_U
1397 are used to match DW_AT_location at the caller's
1398 DW_TAG_call_site_parameter.
1400 Function always returns non-NULL value. It throws NO_ENTRY_VALUE_ERROR if it
1401 cannot resolve the parameter for any reason. */
1403 static struct value *
1404 value_of_dwarf_reg_entry (struct type *type, struct frame_info *frame,
1405 enum call_site_parameter_kind kind,
1406 union call_site_parameter_u kind_u)
1408 struct type *checked_type = check_typedef (type);
1409 struct type *target_type = TYPE_TARGET_TYPE (checked_type);
1410 struct frame_info *caller_frame = get_prev_frame (frame);
1411 struct value *outer_val, *target_val, *val;
1412 struct call_site_parameter *parameter;
1413 struct dwarf2_per_cu_data *caller_per_cu;
1415 parameter = dwarf_expr_reg_to_entry_parameter (frame, kind, kind_u,
1418 outer_val = dwarf_entry_parameter_to_value (parameter, -1 /* deref_size */,
1422 /* Check if DW_AT_call_data_value cannot be used. If it should be
1423 used and it is not available do not fall back to OUTER_VAL - dereferencing
1424 TYPE_CODE_REF with non-entry data value would give current value - not the
1427 if (!TYPE_IS_REFERENCE (checked_type)
1428 || TYPE_TARGET_TYPE (checked_type) == NULL)
1431 target_val = dwarf_entry_parameter_to_value (parameter,
1432 TYPE_LENGTH (target_type),
1433 target_type, caller_frame,
1436 release_value (target_val);
1437 val = allocate_computed_value (type, &entry_data_value_funcs,
1438 target_val /* closure */);
1440 /* Copy the referencing pointer to the new computed value. */
1441 memcpy (value_contents_raw (val), value_contents_raw (outer_val),
1442 TYPE_LENGTH (checked_type));
1443 set_value_lazy (val, 0);
1448 /* Read parameter of TYPE at (callee) FRAME's function entry. DATA and
1449 SIZE are DWARF block used to match DW_AT_location at the caller's
1450 DW_TAG_call_site_parameter.
1452 Function always returns non-NULL value. It throws NO_ENTRY_VALUE_ERROR if it
1453 cannot resolve the parameter for any reason. */
1455 static struct value *
1456 value_of_dwarf_block_entry (struct type *type, struct frame_info *frame,
1457 const gdb_byte *block, size_t block_len)
1459 union call_site_parameter_u kind_u;
1461 kind_u.dwarf_reg = dwarf_block_to_dwarf_reg (block, block + block_len);
1462 if (kind_u.dwarf_reg != -1)
1463 return value_of_dwarf_reg_entry (type, frame, CALL_SITE_PARAMETER_DWARF_REG,
1466 if (dwarf_block_to_fb_offset (block, block + block_len, &kind_u.fb_offset))
1467 return value_of_dwarf_reg_entry (type, frame, CALL_SITE_PARAMETER_FB_OFFSET,
1470 /* This can normally happen - throw NO_ENTRY_VALUE_ERROR to get the message
1471 suppressed during normal operation. The expression can be arbitrary if
1472 there is no caller-callee entry value binding expected. */
1473 throw_error (NO_ENTRY_VALUE_ERROR,
1474 _("DWARF-2 expression error: DW_OP_entry_value is supported "
1475 "only for single DW_OP_reg* or for DW_OP_fbreg(*)"));
1478 struct piece_closure
1480 /* Reference count. */
1483 /* The CU from which this closure's expression came. */
1484 struct dwarf2_per_cu_data *per_cu;
1486 /* The number of pieces used to describe this variable. */
1489 /* The pieces themselves. */
1490 struct dwarf_expr_piece *pieces;
1492 /* Frame ID of frame to which a register value is relative, used
1493 only by DWARF_VALUE_REGISTER. */
1494 struct frame_id frame_id;
1497 /* Allocate a closure for a value formed from separately-described
1500 static struct piece_closure *
1501 allocate_piece_closure (struct dwarf2_per_cu_data *per_cu,
1502 int n_pieces, struct dwarf_expr_piece *pieces,
1503 struct frame_info *frame)
1505 struct piece_closure *c = XCNEW (struct piece_closure);
1510 c->n_pieces = n_pieces;
1511 c->pieces = XCNEWVEC (struct dwarf_expr_piece, n_pieces);
1513 c->frame_id = null_frame_id;
1515 c->frame_id = get_frame_id (frame);
1517 memcpy (c->pieces, pieces, n_pieces * sizeof (struct dwarf_expr_piece));
1518 for (i = 0; i < n_pieces; ++i)
1519 if (c->pieces[i].location == DWARF_VALUE_STACK)
1520 value_incref (c->pieces[i].v.value);
1525 /* Copy NBITS bits from SOURCE to DEST starting at the given bit
1526 offsets. Use the bit order as specified by BITS_BIG_ENDIAN.
1527 Source and destination buffers must not overlap. */
1530 copy_bitwise (gdb_byte *dest, ULONGEST dest_offset,
1531 const gdb_byte *source, ULONGEST source_offset,
1532 ULONGEST nbits, int bits_big_endian)
1534 unsigned int buf, avail;
1539 if (bits_big_endian)
1541 /* Start from the end, then work backwards. */
1542 dest_offset += nbits - 1;
1543 dest += dest_offset / 8;
1544 dest_offset = 7 - dest_offset % 8;
1545 source_offset += nbits - 1;
1546 source += source_offset / 8;
1547 source_offset = 7 - source_offset % 8;
1551 dest += dest_offset / 8;
1553 source += source_offset / 8;
1557 /* Fill BUF with DEST_OFFSET bits from the destination and 8 -
1558 SOURCE_OFFSET bits from the source. */
1559 buf = *(bits_big_endian ? source-- : source++) >> source_offset;
1560 buf <<= dest_offset;
1561 buf |= *dest & ((1 << dest_offset) - 1);
1563 /* NBITS: bits yet to be written; AVAIL: BUF's fill level. */
1564 nbits += dest_offset;
1565 avail = dest_offset + 8 - source_offset;
1567 /* Flush 8 bits from BUF, if appropriate. */
1568 if (nbits >= 8 && avail >= 8)
1570 *(bits_big_endian ? dest-- : dest++) = buf;
1576 /* Copy the middle part. */
1579 size_t len = nbits / 8;
1581 /* Use a faster method for byte-aligned copies. */
1584 if (bits_big_endian)
1588 memcpy (dest + 1, source + 1, len);
1592 memcpy (dest, source, len);
1601 buf |= *(bits_big_endian ? source-- : source++) << avail;
1602 *(bits_big_endian ? dest-- : dest++) = buf;
1609 /* Write the last byte. */
1613 buf |= *source << avail;
1615 buf &= (1 << nbits) - 1;
1616 *dest = (*dest & (~0 << nbits)) | buf;
1622 namespace selftests {
1624 /* Helper function for the unit test of copy_bitwise. Convert NBITS bits
1625 out of BITS, starting at OFFS, to the respective '0'/'1'-string. MSB0
1626 specifies whether to assume big endian bit numbering. Store the
1627 resulting (not null-terminated) string at STR. */
1630 bits_to_str (char *str, const gdb_byte *bits, ULONGEST offs,
1631 ULONGEST nbits, int msb0)
1636 for (i = offs / 8, j = offs % 8; nbits; i++, j = 0)
1638 unsigned int ch = bits[i];
1639 for (; j < 8 && nbits; j++, nbits--)
1640 *str++ = (ch & (msb0 ? (1 << (7 - j)) : (1 << j))) ? '1' : '0';
1644 /* Check one invocation of copy_bitwise with the given parameters. */
1647 check_copy_bitwise (const gdb_byte *dest, unsigned int dest_offset,
1648 const gdb_byte *source, unsigned int source_offset,
1649 unsigned int nbits, int msb0)
1651 size_t len = align_up (dest_offset + nbits, 8);
1652 char *expected = (char *) alloca (len + 1);
1653 char *actual = (char *) alloca (len + 1);
1654 gdb_byte *buf = (gdb_byte *) alloca (len / 8);
1656 /* Compose a '0'/'1'-string that represents the expected result of
1658 Bits from [0, DEST_OFFSET) are filled from DEST.
1659 Bits from [DEST_OFFSET, DEST_OFFSET + NBITS) are filled from SOURCE.
1660 Bits from [DEST_OFFSET + NBITS, LEN) are filled from DEST.
1669 We should end up with:
1671 DDDDSSDD (D=dest, S=source)
1673 bits_to_str (expected, dest, 0, len, msb0);
1674 bits_to_str (expected + dest_offset, source, source_offset, nbits, msb0);
1676 /* Fill BUF with data from DEST, apply copy_bitwise, and convert the
1677 result to a '0'/'1'-string. */
1678 memcpy (buf, dest, len / 8);
1679 copy_bitwise (buf, dest_offset, source, source_offset, nbits, msb0);
1680 bits_to_str (actual, buf, 0, len, msb0);
1682 /* Compare the resulting strings. */
1683 expected[len] = actual[len] = '\0';
1684 if (strcmp (expected, actual) != 0)
1685 error (_("copy_bitwise %s != %s (%u+%u -> %u)"),
1686 expected, actual, source_offset, nbits, dest_offset);
1689 /* Unit test for copy_bitwise. */
1692 copy_bitwise_tests (void)
1694 /* Data to be used as both source and destination buffers. The two
1695 arrays below represent the lsb0- and msb0- encoded versions of the
1696 following bit string, respectively:
1697 00000000 00011111 11111111 01001000 10100101 11110010
1698 This pattern is chosen such that it contains:
1699 - constant 0- and 1- chunks of more than a full byte;
1700 - 0/1- and 1/0 transitions on all bit positions within a byte;
1701 - several sufficiently asymmetric bytes.
1703 static const gdb_byte data_lsb0[] = {
1704 0x00, 0xf8, 0xff, 0x12, 0xa5, 0x4f
1706 static const gdb_byte data_msb0[] = {
1707 0x00, 0x1f, 0xff, 0x48, 0xa5, 0xf2
1710 constexpr size_t data_nbits = 8 * sizeof (data_lsb0);
1711 constexpr unsigned max_nbits = 24;
1713 /* Try all combinations of:
1714 lsb0/msb0 bit order (using the respective data array)
1715 X [0, MAX_NBITS] copy bit width
1716 X feasible source offsets for the given copy bit width
1717 X feasible destination offsets
1719 for (int msb0 = 0; msb0 < 2; msb0++)
1721 const gdb_byte *data = msb0 ? data_msb0 : data_lsb0;
1723 for (unsigned int nbits = 1; nbits <= max_nbits; nbits++)
1725 const unsigned int max_offset = data_nbits - nbits;
1727 for (unsigned source_offset = 0;
1728 source_offset <= max_offset;
1731 for (unsigned dest_offset = 0;
1732 dest_offset <= max_offset;
1735 check_copy_bitwise (data + dest_offset / 8,
1737 data + source_offset / 8,
1744 /* Special cases: copy all, copy nothing. */
1745 check_copy_bitwise (data_lsb0, 0, data_msb0, 0, data_nbits, msb0);
1746 check_copy_bitwise (data_msb0, 0, data_lsb0, 0, data_nbits, msb0);
1747 check_copy_bitwise (data, data_nbits - 7, data, 9, 0, msb0);
1751 } /* namespace selftests */
1753 #endif /* GDB_SELF_TEST */
1755 /* Return the number of bytes overlapping a contiguous chunk of N_BITS
1756 bits whose first bit is located at bit offset START. */
1759 bits_to_bytes (ULONGEST start, ULONGEST n_bits)
1761 return (start % 8 + n_bits + 7) / 8;
1765 read_pieced_value (struct value *v)
1768 LONGEST offset = 0, max_offset;
1769 ULONGEST bits_to_skip;
1771 struct piece_closure *c
1772 = (struct piece_closure *) value_computed_closure (v);
1773 std::vector<gdb_byte> buffer;
1775 = gdbarch_bits_big_endian (get_type_arch (value_type (v)));
1777 if (value_type (v) != value_enclosing_type (v))
1778 internal_error (__FILE__, __LINE__,
1779 _("Should not be able to create a lazy value with "
1780 "an enclosing type"));
1782 contents = value_contents_raw (v);
1783 bits_to_skip = 8 * value_offset (v);
1784 if (value_bitsize (v))
1786 bits_to_skip += (8 * value_offset (value_parent (v))
1787 + value_bitpos (v));
1788 max_offset = value_bitsize (v);
1791 max_offset = 8 * TYPE_LENGTH (value_type (v));
1793 /* Advance to the first non-skipped piece. */
1794 for (i = 0; i < c->n_pieces && bits_to_skip >= c->pieces[i].size; i++)
1795 bits_to_skip -= c->pieces[i].size;
1797 for (; i < c->n_pieces && offset < max_offset; i++)
1799 struct dwarf_expr_piece *p = &c->pieces[i];
1800 size_t this_size, this_size_bits;
1802 this_size_bits = p->size - bits_to_skip;
1803 if (this_size_bits > max_offset - offset)
1804 this_size_bits = max_offset - offset;
1806 /* Copy from the source to DEST_BUFFER. */
1807 switch (p->location)
1809 case DWARF_VALUE_REGISTER:
1811 struct frame_info *frame = frame_find_by_id (c->frame_id);
1812 struct gdbarch *arch = get_frame_arch (frame);
1813 int gdb_regnum = dwarf_reg_to_regnum_or_error (arch, p->v.regno);
1814 ULONGEST reg_bits = 8 * register_size (arch, gdb_regnum);
1817 if (gdbarch_byte_order (arch) == BFD_ENDIAN_BIG
1818 && p->offset + p->size < reg_bits)
1820 /* Big-endian, and we want less than full size. */
1821 bits_to_skip += reg_bits - (p->offset + p->size);
1824 bits_to_skip += p->offset;
1826 this_size = bits_to_bytes (bits_to_skip, this_size_bits);
1827 buffer.reserve (this_size);
1829 if (!get_frame_register_bytes (frame, gdb_regnum,
1831 this_size, buffer.data (),
1835 mark_value_bits_optimized_out (v, offset, this_size_bits);
1837 mark_value_bits_unavailable (v, offset, this_size_bits);
1840 copy_bitwise (contents, offset,
1841 buffer.data (), bits_to_skip % 8,
1842 this_size_bits, bits_big_endian);
1846 case DWARF_VALUE_MEMORY:
1847 bits_to_skip += p->offset;
1848 this_size = bits_to_bytes (bits_to_skip, this_size_bits);
1849 buffer.reserve (this_size);
1851 read_value_memory (v, offset,
1852 p->v.mem.in_stack_memory,
1853 p->v.mem.addr + bits_to_skip / 8,
1854 buffer.data (), this_size);
1855 copy_bitwise (contents, offset,
1856 buffer.data (), bits_to_skip % 8,
1857 this_size_bits, bits_big_endian);
1860 case DWARF_VALUE_STACK:
1862 struct objfile *objfile = dwarf2_per_cu_objfile (c->per_cu);
1863 struct gdbarch *objfile_gdbarch = get_objfile_arch (objfile);
1864 ULONGEST stack_value_size_bits
1865 = 8 * TYPE_LENGTH (value_type (p->v.value));
1867 /* Use zeroes if piece reaches beyond stack value. */
1868 if (p->offset + p->size > stack_value_size_bits)
1871 /* Piece is anchored at least significant bit end. */
1872 if (gdbarch_byte_order (objfile_gdbarch) == BFD_ENDIAN_BIG)
1873 bits_to_skip += stack_value_size_bits - p->offset - p->size;
1875 bits_to_skip += p->offset;
1877 copy_bitwise (contents, offset,
1878 value_contents_all (p->v.value),
1880 this_size_bits, bits_big_endian);
1884 case DWARF_VALUE_LITERAL:
1886 ULONGEST literal_size_bits = 8 * p->v.literal.length;
1887 size_t n = this_size_bits;
1889 /* Cut off at the end of the implicit value. */
1890 bits_to_skip += p->offset;
1891 if (bits_to_skip >= literal_size_bits)
1893 if (n > literal_size_bits - bits_to_skip)
1894 n = literal_size_bits - bits_to_skip;
1896 copy_bitwise (contents, offset,
1897 p->v.literal.data, bits_to_skip,
1898 n, bits_big_endian);
1902 /* These bits show up as zeros -- but do not cause the value
1903 to be considered optimized-out. */
1904 case DWARF_VALUE_IMPLICIT_POINTER:
1907 case DWARF_VALUE_OPTIMIZED_OUT:
1908 mark_value_bits_optimized_out (v, offset, this_size_bits);
1912 internal_error (__FILE__, __LINE__, _("invalid location type"));
1915 offset += this_size_bits;
1921 write_pieced_value (struct value *to, struct value *from)
1924 ULONGEST bits_to_skip;
1925 LONGEST offset = 0, max_offset;
1926 const gdb_byte *contents;
1927 struct piece_closure *c
1928 = (struct piece_closure *) value_computed_closure (to);
1929 std::vector<gdb_byte> buffer;
1931 = gdbarch_bits_big_endian (get_type_arch (value_type (to)));
1933 contents = value_contents (from);
1934 bits_to_skip = 8 * value_offset (to);
1935 if (value_bitsize (to))
1937 bits_to_skip += (8 * value_offset (value_parent (to))
1938 + value_bitpos (to));
1939 /* Use the least significant bits of FROM. */
1940 if (gdbarch_byte_order (get_type_arch (value_type (from)))
1943 max_offset = 8 * TYPE_LENGTH (value_type (from));
1944 offset = max_offset - value_bitsize (to);
1947 max_offset = value_bitsize (to);
1950 max_offset = 8 * TYPE_LENGTH (value_type (to));
1952 /* Advance to the first non-skipped piece. */
1953 for (i = 0; i < c->n_pieces && bits_to_skip >= c->pieces[i].size; i++)
1954 bits_to_skip -= c->pieces[i].size;
1956 for (; i < c->n_pieces && offset < max_offset; i++)
1958 struct dwarf_expr_piece *p = &c->pieces[i];
1959 size_t this_size_bits, this_size;
1961 this_size_bits = p->size - bits_to_skip;
1962 if (this_size_bits > max_offset - offset)
1963 this_size_bits = max_offset - offset;
1965 switch (p->location)
1967 case DWARF_VALUE_REGISTER:
1969 struct frame_info *frame = frame_find_by_id (c->frame_id);
1970 struct gdbarch *arch = get_frame_arch (frame);
1971 int gdb_regnum = dwarf_reg_to_regnum_or_error (arch, p->v.regno);
1972 ULONGEST reg_bits = 8 * register_size (arch, gdb_regnum);
1974 if (gdbarch_byte_order (arch) == BFD_ENDIAN_BIG
1975 && p->offset + p->size < reg_bits)
1977 /* Big-endian, and we want less than full size. */
1978 bits_to_skip += reg_bits - (p->offset + p->size);
1981 bits_to_skip += p->offset;
1983 this_size = bits_to_bytes (bits_to_skip, this_size_bits);
1984 buffer.reserve (this_size);
1986 if (bits_to_skip % 8 != 0 || this_size_bits % 8 != 0)
1988 /* Data is copied non-byte-aligned into the register.
1989 Need some bits from original register value. */
1992 if (!get_frame_register_bytes (frame, gdb_regnum,
1994 this_size, buffer.data (),
1998 throw_error (OPTIMIZED_OUT_ERROR,
1999 _("Can't do read-modify-write to "
2000 "update bitfield; containing word "
2001 "has been optimized out"));
2003 throw_error (NOT_AVAILABLE_ERROR,
2004 _("Can't do read-modify-write to update "
2005 "bitfield; containing word "
2010 copy_bitwise (buffer.data (), bits_to_skip % 8,
2012 this_size_bits, bits_big_endian);
2013 put_frame_register_bytes (frame, gdb_regnum,
2015 this_size, buffer.data ());
2018 case DWARF_VALUE_MEMORY:
2020 bits_to_skip += p->offset;
2022 CORE_ADDR start_addr = p->v.mem.addr + bits_to_skip / 8;
2024 if (bits_to_skip % 8 == 0 && this_size_bits % 8 == 0
2027 /* Everything is byte-aligned; no buffer needed. */
2028 write_memory_with_notification (start_addr,
2029 contents + offset / 8,
2030 this_size_bits / 8);
2034 this_size = bits_to_bytes (bits_to_skip, this_size_bits);
2035 buffer.reserve (this_size);
2037 if (bits_to_skip % 8 != 0 || this_size_bits % 8 != 0)
2041 /* Perform a single read for small sizes. */
2042 read_memory (start_addr, buffer.data (), this_size);
2046 /* Only the first and last bytes can possibly have any
2048 read_memory (start_addr, buffer.data (), 1);
2049 read_memory (start_addr + this_size - 1,
2050 &buffer[this_size - 1], 1);
2054 copy_bitwise (buffer.data (), bits_to_skip % 8,
2056 this_size_bits, bits_big_endian);
2057 write_memory_with_notification (start_addr, buffer.data (),
2062 mark_value_bytes_optimized_out (to, 0, TYPE_LENGTH (value_type (to)));
2065 offset += this_size_bits;
2070 /* An implementation of an lval_funcs method to see whether a value is
2071 a synthetic pointer. */
2074 check_pieced_synthetic_pointer (const struct value *value, LONGEST bit_offset,
2077 struct piece_closure *c
2078 = (struct piece_closure *) value_computed_closure (value);
2081 bit_offset += 8 * value_offset (value);
2082 if (value_bitsize (value))
2083 bit_offset += value_bitpos (value);
2085 for (i = 0; i < c->n_pieces && bit_length > 0; i++)
2087 struct dwarf_expr_piece *p = &c->pieces[i];
2088 size_t this_size_bits = p->size;
2092 if (bit_offset >= this_size_bits)
2094 bit_offset -= this_size_bits;
2098 bit_length -= this_size_bits - bit_offset;
2102 bit_length -= this_size_bits;
2104 if (p->location != DWARF_VALUE_IMPLICIT_POINTER)
2111 /* A wrapper function for get_frame_address_in_block. */
2114 get_frame_address_in_block_wrapper (void *baton)
2116 return get_frame_address_in_block ((struct frame_info *) baton);
2119 /* Fetch a DW_AT_const_value through a synthetic pointer. */
2121 static struct value *
2122 fetch_const_value_from_synthetic_pointer (sect_offset die, LONGEST byte_offset,
2123 struct dwarf2_per_cu_data *per_cu,
2126 struct value *result = NULL;
2127 struct obstack temp_obstack;
2128 struct cleanup *cleanup;
2129 const gdb_byte *bytes;
2132 obstack_init (&temp_obstack);
2133 cleanup = make_cleanup_obstack_free (&temp_obstack);
2134 bytes = dwarf2_fetch_constant_bytes (die, per_cu, &temp_obstack, &len);
2138 if (byte_offset >= 0
2139 && byte_offset + TYPE_LENGTH (TYPE_TARGET_TYPE (type)) <= len)
2141 bytes += byte_offset;
2142 result = value_from_contents (TYPE_TARGET_TYPE (type), bytes);
2145 invalid_synthetic_pointer ();
2148 result = allocate_optimized_out_value (TYPE_TARGET_TYPE (type));
2150 do_cleanups (cleanup);
2155 /* Fetch the value pointed to by a synthetic pointer. */
2157 static struct value *
2158 indirect_synthetic_pointer (sect_offset die, LONGEST byte_offset,
2159 struct dwarf2_per_cu_data *per_cu,
2160 struct frame_info *frame, struct type *type)
2162 /* Fetch the location expression of the DIE we're pointing to. */
2163 struct dwarf2_locexpr_baton baton
2164 = dwarf2_fetch_die_loc_sect_off (die, per_cu,
2165 get_frame_address_in_block_wrapper, frame);
2167 /* Get type of pointed-to DIE. */
2168 struct type *orig_type = dwarf2_fetch_die_type_sect_off (die, per_cu);
2169 if (orig_type == NULL)
2170 invalid_synthetic_pointer ();
2172 /* If pointed-to DIE has a DW_AT_location, evaluate it and return the
2173 resulting value. Otherwise, it may have a DW_AT_const_value instead,
2174 or it may've been optimized out. */
2175 if (baton.data != NULL)
2176 return dwarf2_evaluate_loc_desc_full (orig_type, frame, baton.data,
2177 baton.size, baton.per_cu,
2178 TYPE_TARGET_TYPE (type),
2181 return fetch_const_value_from_synthetic_pointer (die, byte_offset, per_cu,
2185 /* An implementation of an lval_funcs method to indirect through a
2186 pointer. This handles the synthetic pointer case when needed. */
2188 static struct value *
2189 indirect_pieced_value (struct value *value)
2191 struct piece_closure *c
2192 = (struct piece_closure *) value_computed_closure (value);
2194 struct frame_info *frame;
2195 struct dwarf2_locexpr_baton baton;
2198 struct dwarf_expr_piece *piece = NULL;
2199 LONGEST byte_offset;
2200 enum bfd_endian byte_order;
2202 type = check_typedef (value_type (value));
2203 if (TYPE_CODE (type) != TYPE_CODE_PTR)
2206 bit_length = 8 * TYPE_LENGTH (type);
2207 bit_offset = 8 * value_offset (value);
2208 if (value_bitsize (value))
2209 bit_offset += value_bitpos (value);
2211 for (i = 0; i < c->n_pieces && bit_length > 0; i++)
2213 struct dwarf_expr_piece *p = &c->pieces[i];
2214 size_t this_size_bits = p->size;
2218 if (bit_offset >= this_size_bits)
2220 bit_offset -= this_size_bits;
2224 bit_length -= this_size_bits - bit_offset;
2228 bit_length -= this_size_bits;
2230 if (p->location != DWARF_VALUE_IMPLICIT_POINTER)
2233 if (bit_length != 0)
2234 error (_("Invalid use of DW_OP_implicit_pointer"));
2240 gdb_assert (piece != NULL);
2241 frame = get_selected_frame (_("No frame selected."));
2243 /* This is an offset requested by GDB, such as value subscripts.
2244 However, due to how synthetic pointers are implemented, this is
2245 always presented to us as a pointer type. This means we have to
2246 sign-extend it manually as appropriate. Use raw
2247 extract_signed_integer directly rather than value_as_address and
2248 sign extend afterwards on architectures that would need it
2249 (mostly everywhere except MIPS, which has signed addresses) as
2250 the later would go through gdbarch_pointer_to_address and thus
2251 return a CORE_ADDR with high bits set on architectures that
2252 encode address spaces and other things in CORE_ADDR. */
2253 byte_order = gdbarch_byte_order (get_frame_arch (frame));
2254 byte_offset = extract_signed_integer (value_contents (value),
2255 TYPE_LENGTH (type), byte_order);
2256 byte_offset += piece->v.ptr.offset;
2258 return indirect_synthetic_pointer (piece->v.ptr.die_sect_off,
2259 byte_offset, c->per_cu,
2263 /* Implementation of the coerce_ref method of lval_funcs for synthetic C++
2266 static struct value *
2267 coerce_pieced_ref (const struct value *value)
2269 struct type *type = check_typedef (value_type (value));
2271 if (value_bits_synthetic_pointer (value, value_embedded_offset (value),
2272 TARGET_CHAR_BIT * TYPE_LENGTH (type)))
2274 const struct piece_closure *closure
2275 = (struct piece_closure *) value_computed_closure (value);
2276 struct frame_info *frame
2277 = get_selected_frame (_("No frame selected."));
2279 /* gdb represents synthetic pointers as pieced values with a single
2281 gdb_assert (closure != NULL);
2282 gdb_assert (closure->n_pieces == 1);
2284 return indirect_synthetic_pointer (closure->pieces->v.ptr.die_sect_off,
2285 closure->pieces->v.ptr.offset,
2286 closure->per_cu, frame, type);
2290 /* Else: not a synthetic reference; do nothing. */
2296 copy_pieced_value_closure (const struct value *v)
2298 struct piece_closure *c
2299 = (struct piece_closure *) value_computed_closure (v);
2306 free_pieced_value_closure (struct value *v)
2308 struct piece_closure *c
2309 = (struct piece_closure *) value_computed_closure (v);
2316 for (i = 0; i < c->n_pieces; ++i)
2317 if (c->pieces[i].location == DWARF_VALUE_STACK)
2318 value_free (c->pieces[i].v.value);
2325 /* Functions for accessing a variable described by DW_OP_piece. */
2326 static const struct lval_funcs pieced_value_funcs = {
2329 indirect_pieced_value,
2331 check_pieced_synthetic_pointer,
2332 copy_pieced_value_closure,
2333 free_pieced_value_closure
2336 /* Evaluate a location description, starting at DATA and with length
2337 SIZE, to find the current location of variable of TYPE in the
2338 context of FRAME. If SUBOBJ_TYPE is non-NULL, return instead the
2339 location of the subobject of type SUBOBJ_TYPE at byte offset
2340 SUBOBJ_BYTE_OFFSET within the variable of type TYPE. */
2342 static struct value *
2343 dwarf2_evaluate_loc_desc_full (struct type *type, struct frame_info *frame,
2344 const gdb_byte *data, size_t size,
2345 struct dwarf2_per_cu_data *per_cu,
2346 struct type *subobj_type,
2347 LONGEST subobj_byte_offset)
2349 struct value *retval;
2350 struct objfile *objfile = dwarf2_per_cu_objfile (per_cu);
2352 if (subobj_type == NULL)
2355 subobj_byte_offset = 0;
2357 else if (subobj_byte_offset < 0)
2358 invalid_synthetic_pointer ();
2361 return allocate_optimized_out_value (subobj_type);
2363 dwarf_evaluate_loc_desc ctx;
2365 ctx.per_cu = per_cu;
2366 ctx.obj_address = 0;
2368 scoped_value_mark free_values;
2370 ctx.gdbarch = get_objfile_arch (objfile);
2371 ctx.addr_size = dwarf2_per_cu_addr_size (per_cu);
2372 ctx.ref_addr_size = dwarf2_per_cu_ref_addr_size (per_cu);
2373 ctx.offset = dwarf2_per_cu_text_offset (per_cu);
2377 ctx.eval (data, size);
2379 CATCH (ex, RETURN_MASK_ERROR)
2381 if (ex.error == NOT_AVAILABLE_ERROR)
2383 free_values.free_to_mark ();
2384 retval = allocate_value (subobj_type);
2385 mark_value_bytes_unavailable (retval, 0,
2386 TYPE_LENGTH (subobj_type));
2389 else if (ex.error == NO_ENTRY_VALUE_ERROR)
2391 if (entry_values_debug)
2392 exception_print (gdb_stdout, ex);
2393 free_values.free_to_mark ();
2394 return allocate_optimized_out_value (subobj_type);
2397 throw_exception (ex);
2401 if (ctx.num_pieces > 0)
2403 struct piece_closure *c;
2404 ULONGEST bit_size = 0;
2407 for (i = 0; i < ctx.num_pieces; ++i)
2408 bit_size += ctx.pieces[i].size;
2409 if (8 * (subobj_byte_offset + TYPE_LENGTH (subobj_type)) > bit_size)
2410 invalid_synthetic_pointer ();
2412 c = allocate_piece_closure (per_cu, ctx.num_pieces, ctx.pieces,
2414 /* We must clean up the value chain after creating the piece
2415 closure but before allocating the result. */
2416 free_values.free_to_mark ();
2417 retval = allocate_computed_value (subobj_type,
2418 &pieced_value_funcs, c);
2419 set_value_offset (retval, subobj_byte_offset);
2423 switch (ctx.location)
2425 case DWARF_VALUE_REGISTER:
2427 struct gdbarch *arch = get_frame_arch (frame);
2429 = longest_to_int (value_as_long (ctx.fetch (0)));
2430 int gdb_regnum = dwarf_reg_to_regnum_or_error (arch, dwarf_regnum);
2432 if (subobj_byte_offset != 0)
2433 error (_("cannot use offset on synthetic pointer to register"));
2434 free_values.free_to_mark ();
2435 retval = value_from_register (subobj_type, gdb_regnum, frame);
2436 if (value_optimized_out (retval))
2440 /* This means the register has undefined value / was
2441 not saved. As we're computing the location of some
2442 variable etc. in the program, not a value for
2443 inspecting a register ($pc, $sp, etc.), return a
2444 generic optimized out value instead, so that we show
2445 <optimized out> instead of <not saved>. */
2446 tmp = allocate_value (subobj_type);
2447 value_contents_copy (tmp, 0, retval, 0,
2448 TYPE_LENGTH (subobj_type));
2454 case DWARF_VALUE_MEMORY:
2456 struct type *ptr_type;
2457 CORE_ADDR address = ctx.fetch_address (0);
2458 int in_stack_memory = ctx.fetch_in_stack_memory (0);
2460 /* DW_OP_deref_size (and possibly other operations too) may
2461 create a pointer instead of an address. Ideally, the
2462 pointer to address conversion would be performed as part
2463 of those operations, but the type of the object to
2464 which the address refers is not known at the time of
2465 the operation. Therefore, we do the conversion here
2466 since the type is readily available. */
2468 switch (TYPE_CODE (subobj_type))
2470 case TYPE_CODE_FUNC:
2471 case TYPE_CODE_METHOD:
2472 ptr_type = builtin_type (ctx.gdbarch)->builtin_func_ptr;
2475 ptr_type = builtin_type (ctx.gdbarch)->builtin_data_ptr;
2478 address = value_as_address (value_from_pointer (ptr_type, address));
2480 free_values.free_to_mark ();
2481 retval = value_at_lazy (subobj_type,
2482 address + subobj_byte_offset);
2483 if (in_stack_memory)
2484 set_value_stack (retval, 1);
2488 case DWARF_VALUE_STACK:
2490 struct value *value = ctx.fetch (0);
2491 size_t n = TYPE_LENGTH (value_type (value));
2492 size_t len = TYPE_LENGTH (subobj_type);
2493 size_t max = TYPE_LENGTH (type);
2494 struct gdbarch *objfile_gdbarch = get_objfile_arch (objfile);
2495 struct cleanup *cleanup;
2497 if (subobj_byte_offset + len > max)
2498 invalid_synthetic_pointer ();
2500 /* Preserve VALUE because we are going to free values back
2501 to the mark, but we still need the value contents
2503 value_incref (value);
2504 free_values.free_to_mark ();
2505 cleanup = make_cleanup_value_free (value);
2507 retval = allocate_value (subobj_type);
2509 /* The given offset is relative to the actual object. */
2510 if (gdbarch_byte_order (objfile_gdbarch) == BFD_ENDIAN_BIG)
2511 subobj_byte_offset += n - max;
2513 memcpy (value_contents_raw (retval),
2514 value_contents_all (value) + subobj_byte_offset, len);
2516 do_cleanups (cleanup);
2520 case DWARF_VALUE_LITERAL:
2523 size_t n = TYPE_LENGTH (subobj_type);
2525 if (subobj_byte_offset + n > ctx.len)
2526 invalid_synthetic_pointer ();
2528 free_values.free_to_mark ();
2529 retval = allocate_value (subobj_type);
2530 contents = value_contents_raw (retval);
2531 memcpy (contents, ctx.data + subobj_byte_offset, n);
2535 case DWARF_VALUE_OPTIMIZED_OUT:
2536 free_values.free_to_mark ();
2537 retval = allocate_optimized_out_value (subobj_type);
2540 /* DWARF_VALUE_IMPLICIT_POINTER was converted to a pieced
2541 operation by execute_stack_op. */
2542 case DWARF_VALUE_IMPLICIT_POINTER:
2543 /* DWARF_VALUE_OPTIMIZED_OUT can't occur in this context --
2544 it can only be encountered when making a piece. */
2546 internal_error (__FILE__, __LINE__, _("invalid location type"));
2550 set_value_initialized (retval, ctx.initialized);
2555 /* The exported interface to dwarf2_evaluate_loc_desc_full; it always
2556 passes 0 as the byte_offset. */
2559 dwarf2_evaluate_loc_desc (struct type *type, struct frame_info *frame,
2560 const gdb_byte *data, size_t size,
2561 struct dwarf2_per_cu_data *per_cu)
2563 return dwarf2_evaluate_loc_desc_full (type, frame, data, size, per_cu,
2567 /* Evaluates a dwarf expression and stores the result in VAL, expecting
2568 that the dwarf expression only produces a single CORE_ADDR. FRAME is the
2569 frame in which the expression is evaluated. ADDR is a context (location of
2570 a variable) and might be needed to evaluate the location expression.
2571 Returns 1 on success, 0 otherwise. */
2574 dwarf2_locexpr_baton_eval (const struct dwarf2_locexpr_baton *dlbaton,
2575 struct frame_info *frame,
2579 struct objfile *objfile;
2581 if (dlbaton == NULL || dlbaton->size == 0)
2584 dwarf_evaluate_loc_desc ctx;
2587 ctx.per_cu = dlbaton->per_cu;
2588 ctx.obj_address = addr;
2590 objfile = dwarf2_per_cu_objfile (dlbaton->per_cu);
2592 ctx.gdbarch = get_objfile_arch (objfile);
2593 ctx.addr_size = dwarf2_per_cu_addr_size (dlbaton->per_cu);
2594 ctx.ref_addr_size = dwarf2_per_cu_ref_addr_size (dlbaton->per_cu);
2595 ctx.offset = dwarf2_per_cu_text_offset (dlbaton->per_cu);
2597 ctx.eval (dlbaton->data, dlbaton->size);
2599 switch (ctx.location)
2601 case DWARF_VALUE_REGISTER:
2602 case DWARF_VALUE_MEMORY:
2603 case DWARF_VALUE_STACK:
2604 *valp = ctx.fetch_address (0);
2605 if (ctx.location == DWARF_VALUE_REGISTER)
2606 *valp = ctx.read_addr_from_reg (*valp);
2608 case DWARF_VALUE_LITERAL:
2609 *valp = extract_signed_integer (ctx.data, ctx.len,
2610 gdbarch_byte_order (ctx.gdbarch));
2612 /* Unsupported dwarf values. */
2613 case DWARF_VALUE_OPTIMIZED_OUT:
2614 case DWARF_VALUE_IMPLICIT_POINTER:
2621 /* See dwarf2loc.h. */
2624 dwarf2_evaluate_property (const struct dynamic_prop *prop,
2625 struct frame_info *frame,
2626 struct property_addr_info *addr_stack,
2632 if (frame == NULL && has_stack_frames ())
2633 frame = get_selected_frame (NULL);
2639 const struct dwarf2_property_baton *baton
2640 = (const struct dwarf2_property_baton *) prop->data.baton;
2642 if (dwarf2_locexpr_baton_eval (&baton->locexpr, frame,
2643 addr_stack ? addr_stack->addr : 0,
2646 if (baton->referenced_type)
2648 struct value *val = value_at (baton->referenced_type, *value);
2650 *value = value_as_address (val);
2659 struct dwarf2_property_baton *baton
2660 = (struct dwarf2_property_baton *) prop->data.baton;
2661 CORE_ADDR pc = get_frame_address_in_block (frame);
2662 const gdb_byte *data;
2666 data = dwarf2_find_location_expression (&baton->loclist, &size, pc);
2669 val = dwarf2_evaluate_loc_desc (baton->referenced_type, frame, data,
2670 size, baton->loclist.per_cu);
2671 if (!value_optimized_out (val))
2673 *value = value_as_address (val);
2681 *value = prop->data.const_val;
2684 case PROP_ADDR_OFFSET:
2686 struct dwarf2_property_baton *baton
2687 = (struct dwarf2_property_baton *) prop->data.baton;
2688 struct property_addr_info *pinfo;
2691 for (pinfo = addr_stack; pinfo != NULL; pinfo = pinfo->next)
2692 if (pinfo->type == baton->referenced_type)
2695 error (_("cannot find reference address for offset property"));
2696 if (pinfo->valaddr != NULL)
2697 val = value_from_contents
2698 (baton->offset_info.type,
2699 pinfo->valaddr + baton->offset_info.offset);
2701 val = value_at (baton->offset_info.type,
2702 pinfo->addr + baton->offset_info.offset);
2703 *value = value_as_address (val);
2711 /* See dwarf2loc.h. */
2714 dwarf2_compile_property_to_c (string_file &stream,
2715 const char *result_name,
2716 struct gdbarch *gdbarch,
2717 unsigned char *registers_used,
2718 const struct dynamic_prop *prop,
2722 struct dwarf2_property_baton *baton
2723 = (struct dwarf2_property_baton *) prop->data.baton;
2724 const gdb_byte *data;
2726 struct dwarf2_per_cu_data *per_cu;
2728 if (prop->kind == PROP_LOCEXPR)
2730 data = baton->locexpr.data;
2731 size = baton->locexpr.size;
2732 per_cu = baton->locexpr.per_cu;
2736 gdb_assert (prop->kind == PROP_LOCLIST);
2738 data = dwarf2_find_location_expression (&baton->loclist, &size, pc);
2739 per_cu = baton->loclist.per_cu;
2742 compile_dwarf_bounds_to_c (stream, result_name, prop, sym, pc,
2743 gdbarch, registers_used,
2744 dwarf2_per_cu_addr_size (per_cu),
2745 data, data + size, per_cu);
2749 /* Helper functions and baton for dwarf2_loc_desc_get_symbol_read_needs. */
2751 class symbol_needs_eval_context : public dwarf_expr_context
2755 enum symbol_needs_kind needs;
2756 struct dwarf2_per_cu_data *per_cu;
2758 /* Reads from registers do require a frame. */
2759 CORE_ADDR read_addr_from_reg (int regnum) OVERRIDE
2761 needs = SYMBOL_NEEDS_FRAME;
2765 /* "get_reg_value" callback: Reads from registers do require a
2768 struct value *get_reg_value (struct type *type, int regnum) OVERRIDE
2770 needs = SYMBOL_NEEDS_FRAME;
2771 return value_zero (type, not_lval);
2774 /* Reads from memory do not require a frame. */
2775 void read_mem (gdb_byte *buf, CORE_ADDR addr, size_t len) OVERRIDE
2777 memset (buf, 0, len);
2780 /* Frame-relative accesses do require a frame. */
2781 void get_frame_base (const gdb_byte **start, size_t *length) OVERRIDE
2783 static gdb_byte lit0 = DW_OP_lit0;
2788 needs = SYMBOL_NEEDS_FRAME;
2791 /* CFA accesses require a frame. */
2792 CORE_ADDR get_frame_cfa () OVERRIDE
2794 needs = SYMBOL_NEEDS_FRAME;
2798 CORE_ADDR get_frame_pc () OVERRIDE
2800 needs = SYMBOL_NEEDS_FRAME;
2804 /* Thread-local accesses require registers, but not a frame. */
2805 CORE_ADDR get_tls_address (CORE_ADDR offset) OVERRIDE
2807 if (needs <= SYMBOL_NEEDS_REGISTERS)
2808 needs = SYMBOL_NEEDS_REGISTERS;
2812 /* Helper interface of per_cu_dwarf_call for
2813 dwarf2_loc_desc_get_symbol_read_needs. */
2815 void dwarf_call (cu_offset die_offset) OVERRIDE
2817 per_cu_dwarf_call (this, die_offset, per_cu);
2820 /* DW_OP_entry_value accesses require a caller, therefore a
2823 void push_dwarf_reg_entry_value (enum call_site_parameter_kind kind,
2824 union call_site_parameter_u kind_u,
2825 int deref_size) OVERRIDE
2827 needs = SYMBOL_NEEDS_FRAME;
2829 /* The expression may require some stub values on DWARF stack. */
2830 push_address (0, 0);
2833 /* DW_OP_GNU_addr_index doesn't require a frame. */
2835 CORE_ADDR get_addr_index (unsigned int index) OVERRIDE
2837 /* Nothing to do. */
2841 /* DW_OP_push_object_address has a frame already passed through. */
2843 CORE_ADDR get_object_address () OVERRIDE
2845 /* Nothing to do. */
2850 /* Compute the correct symbol_needs_kind value for the location
2851 expression at DATA (length SIZE). */
2853 static enum symbol_needs_kind
2854 dwarf2_loc_desc_get_symbol_read_needs (const gdb_byte *data, size_t size,
2855 struct dwarf2_per_cu_data *per_cu)
2858 struct objfile *objfile = dwarf2_per_cu_objfile (per_cu);
2860 scoped_value_mark free_values;
2862 symbol_needs_eval_context ctx;
2864 ctx.needs = SYMBOL_NEEDS_NONE;
2865 ctx.per_cu = per_cu;
2866 ctx.gdbarch = get_objfile_arch (objfile);
2867 ctx.addr_size = dwarf2_per_cu_addr_size (per_cu);
2868 ctx.ref_addr_size = dwarf2_per_cu_ref_addr_size (per_cu);
2869 ctx.offset = dwarf2_per_cu_text_offset (per_cu);
2871 ctx.eval (data, size);
2873 in_reg = ctx.location == DWARF_VALUE_REGISTER;
2875 if (ctx.num_pieces > 0)
2879 /* If the location has several pieces, and any of them are in
2880 registers, then we will need a frame to fetch them from. */
2881 for (i = 0; i < ctx.num_pieces; i++)
2882 if (ctx.pieces[i].location == DWARF_VALUE_REGISTER)
2887 ctx.needs = SYMBOL_NEEDS_FRAME;
2891 /* A helper function that throws an unimplemented error mentioning a
2892 given DWARF operator. */
2895 unimplemented (unsigned int op)
2897 const char *name = get_DW_OP_name (op);
2900 error (_("DWARF operator %s cannot be translated to an agent expression"),
2903 error (_("Unknown DWARF operator 0x%02x cannot be translated "
2904 "to an agent expression"),
2910 This is basically a wrapper on gdbarch_dwarf2_reg_to_regnum so that we
2911 can issue a complaint, which is better than having every target's
2912 implementation of dwarf2_reg_to_regnum do it. */
2915 dwarf_reg_to_regnum (struct gdbarch *arch, int dwarf_reg)
2917 int reg = gdbarch_dwarf2_reg_to_regnum (arch, dwarf_reg);
2921 complaint (&symfile_complaints,
2922 _("bad DWARF register number %d"), dwarf_reg);
2927 /* Subroutine of dwarf_reg_to_regnum_or_error to simplify it.
2928 Throw an error because DWARF_REG is bad. */
2931 throw_bad_regnum_error (ULONGEST dwarf_reg)
2933 /* Still want to print -1 as "-1".
2934 We *could* have int and ULONGEST versions of dwarf2_reg_to_regnum_or_error
2935 but that's overkill for now. */
2936 if ((int) dwarf_reg == dwarf_reg)
2937 error (_("Unable to access DWARF register number %d"), (int) dwarf_reg);
2938 error (_("Unable to access DWARF register number %s"),
2939 pulongest (dwarf_reg));
2942 /* See dwarf2loc.h. */
2945 dwarf_reg_to_regnum_or_error (struct gdbarch *arch, ULONGEST dwarf_reg)
2949 if (dwarf_reg > INT_MAX)
2950 throw_bad_regnum_error (dwarf_reg);
2951 /* Yes, we will end up issuing a complaint and an error if DWARF_REG is
2952 bad, but that's ok. */
2953 reg = dwarf_reg_to_regnum (arch, (int) dwarf_reg);
2955 throw_bad_regnum_error (dwarf_reg);
2959 /* A helper function that emits an access to memory. ARCH is the
2960 target architecture. EXPR is the expression which we are building.
2961 NBITS is the number of bits we want to read. This emits the
2962 opcodes needed to read the memory and then extract the desired
2966 access_memory (struct gdbarch *arch, struct agent_expr *expr, ULONGEST nbits)
2968 ULONGEST nbytes = (nbits + 7) / 8;
2970 gdb_assert (nbytes > 0 && nbytes <= sizeof (LONGEST));
2973 ax_trace_quick (expr, nbytes);
2976 ax_simple (expr, aop_ref8);
2977 else if (nbits <= 16)
2978 ax_simple (expr, aop_ref16);
2979 else if (nbits <= 32)
2980 ax_simple (expr, aop_ref32);
2982 ax_simple (expr, aop_ref64);
2984 /* If we read exactly the number of bytes we wanted, we're done. */
2985 if (8 * nbytes == nbits)
2988 if (gdbarch_bits_big_endian (arch))
2990 /* On a bits-big-endian machine, we want the high-order
2992 ax_const_l (expr, 8 * nbytes - nbits);
2993 ax_simple (expr, aop_rsh_unsigned);
2997 /* On a bits-little-endian box, we want the low-order NBITS. */
2998 ax_zero_ext (expr, nbits);
3002 /* A helper function to return the frame's PC. */
3005 get_ax_pc (void *baton)
3007 struct agent_expr *expr = (struct agent_expr *) baton;
3012 /* Compile a DWARF location expression to an agent expression.
3014 EXPR is the agent expression we are building.
3015 LOC is the agent value we modify.
3016 ARCH is the architecture.
3017 ADDR_SIZE is the size of addresses, in bytes.
3018 OP_PTR is the start of the location expression.
3019 OP_END is one past the last byte of the location expression.
3021 This will throw an exception for various kinds of errors -- for
3022 example, if the expression cannot be compiled, or if the expression
3026 dwarf2_compile_expr_to_ax (struct agent_expr *expr, struct axs_value *loc,
3027 struct gdbarch *arch, unsigned int addr_size,
3028 const gdb_byte *op_ptr, const gdb_byte *op_end,
3029 struct dwarf2_per_cu_data *per_cu)
3032 std::vector<int> dw_labels, patches;
3033 const gdb_byte * const base = op_ptr;
3034 const gdb_byte *previous_piece = op_ptr;
3035 enum bfd_endian byte_order = gdbarch_byte_order (arch);
3036 ULONGEST bits_collected = 0;
3037 unsigned int addr_size_bits = 8 * addr_size;
3038 int bits_big_endian = gdbarch_bits_big_endian (arch);
3040 std::vector<int> offsets (op_end - op_ptr, -1);
3042 /* By default we are making an address. */
3043 loc->kind = axs_lvalue_memory;
3045 while (op_ptr < op_end)
3047 enum dwarf_location_atom op = (enum dwarf_location_atom) *op_ptr;
3048 uint64_t uoffset, reg;
3052 offsets[op_ptr - base] = expr->len;
3055 /* Our basic approach to code generation is to map DWARF
3056 operations directly to AX operations. However, there are
3059 First, DWARF works on address-sized units, but AX always uses
3060 LONGEST. For most operations we simply ignore this
3061 difference; instead we generate sign extensions as needed
3062 before division and comparison operations. It would be nice
3063 to omit the sign extensions, but there is no way to determine
3064 the size of the target's LONGEST. (This code uses the size
3065 of the host LONGEST in some cases -- that is a bug but it is
3068 Second, some DWARF operations cannot be translated to AX.
3069 For these we simply fail. See
3070 http://sourceware.org/bugzilla/show_bug.cgi?id=11662. */
3105 ax_const_l (expr, op - DW_OP_lit0);
3109 uoffset = extract_unsigned_integer (op_ptr, addr_size, byte_order);
3110 op_ptr += addr_size;
3111 /* Some versions of GCC emit DW_OP_addr before
3112 DW_OP_GNU_push_tls_address. In this case the value is an
3113 index, not an address. We don't support things like
3114 branching between the address and the TLS op. */
3115 if (op_ptr >= op_end || *op_ptr != DW_OP_GNU_push_tls_address)
3116 uoffset += dwarf2_per_cu_text_offset (per_cu);
3117 ax_const_l (expr, uoffset);
3121 ax_const_l (expr, extract_unsigned_integer (op_ptr, 1, byte_order));
3125 ax_const_l (expr, extract_signed_integer (op_ptr, 1, byte_order));
3129 ax_const_l (expr, extract_unsigned_integer (op_ptr, 2, byte_order));
3133 ax_const_l (expr, extract_signed_integer (op_ptr, 2, byte_order));
3137 ax_const_l (expr, extract_unsigned_integer (op_ptr, 4, byte_order));
3141 ax_const_l (expr, extract_signed_integer (op_ptr, 4, byte_order));
3145 ax_const_l (expr, extract_unsigned_integer (op_ptr, 8, byte_order));
3149 ax_const_l (expr, extract_signed_integer (op_ptr, 8, byte_order));
3153 op_ptr = safe_read_uleb128 (op_ptr, op_end, &uoffset);
3154 ax_const_l (expr, uoffset);
3157 op_ptr = safe_read_sleb128 (op_ptr, op_end, &offset);
3158 ax_const_l (expr, offset);
3193 dwarf_expr_require_composition (op_ptr, op_end, "DW_OP_regx");
3194 loc->u.reg = dwarf_reg_to_regnum_or_error (arch, op - DW_OP_reg0);
3195 loc->kind = axs_lvalue_register;
3199 op_ptr = safe_read_uleb128 (op_ptr, op_end, ®);
3200 dwarf_expr_require_composition (op_ptr, op_end, "DW_OP_regx");
3201 loc->u.reg = dwarf_reg_to_regnum_or_error (arch, reg);
3202 loc->kind = axs_lvalue_register;
3205 case DW_OP_implicit_value:
3209 op_ptr = safe_read_uleb128 (op_ptr, op_end, &len);
3210 if (op_ptr + len > op_end)
3211 error (_("DW_OP_implicit_value: too few bytes available."));
3212 if (len > sizeof (ULONGEST))
3213 error (_("Cannot translate DW_OP_implicit_value of %d bytes"),
3216 ax_const_l (expr, extract_unsigned_integer (op_ptr, len,
3219 dwarf_expr_require_composition (op_ptr, op_end,
3220 "DW_OP_implicit_value");
3222 loc->kind = axs_rvalue;
3226 case DW_OP_stack_value:
3227 dwarf_expr_require_composition (op_ptr, op_end, "DW_OP_stack_value");
3228 loc->kind = axs_rvalue;
3263 op_ptr = safe_read_sleb128 (op_ptr, op_end, &offset);
3264 i = dwarf_reg_to_regnum_or_error (arch, op - DW_OP_breg0);
3268 ax_const_l (expr, offset);
3269 ax_simple (expr, aop_add);
3274 op_ptr = safe_read_uleb128 (op_ptr, op_end, ®);
3275 op_ptr = safe_read_sleb128 (op_ptr, op_end, &offset);
3276 i = dwarf_reg_to_regnum_or_error (arch, reg);
3280 ax_const_l (expr, offset);
3281 ax_simple (expr, aop_add);
3287 const gdb_byte *datastart;
3289 const struct block *b;
3290 struct symbol *framefunc;
3292 b = block_for_pc (expr->scope);
3295 error (_("No block found for address"));
3297 framefunc = block_linkage_function (b);
3300 error (_("No function found for block"));
3302 func_get_frame_base_dwarf_block (framefunc, expr->scope,
3303 &datastart, &datalen);
3305 op_ptr = safe_read_sleb128 (op_ptr, op_end, &offset);
3306 dwarf2_compile_expr_to_ax (expr, loc, arch, addr_size, datastart,
3307 datastart + datalen, per_cu);
3308 if (loc->kind == axs_lvalue_register)
3309 require_rvalue (expr, loc);
3313 ax_const_l (expr, offset);
3314 ax_simple (expr, aop_add);
3317 loc->kind = axs_lvalue_memory;
3322 ax_simple (expr, aop_dup);
3326 ax_simple (expr, aop_pop);
3331 ax_pick (expr, offset);
3335 ax_simple (expr, aop_swap);
3343 ax_simple (expr, aop_rot);
3347 case DW_OP_deref_size:
3351 if (op == DW_OP_deref_size)
3356 if (size != 1 && size != 2 && size != 4 && size != 8)
3357 error (_("Unsupported size %d in %s"),
3358 size, get_DW_OP_name (op));
3359 access_memory (arch, expr, size * TARGET_CHAR_BIT);
3364 /* Sign extend the operand. */
3365 ax_ext (expr, addr_size_bits);
3366 ax_simple (expr, aop_dup);
3367 ax_const_l (expr, 0);
3368 ax_simple (expr, aop_less_signed);
3369 ax_simple (expr, aop_log_not);
3370 i = ax_goto (expr, aop_if_goto);
3371 /* We have to emit 0 - X. */
3372 ax_const_l (expr, 0);
3373 ax_simple (expr, aop_swap);
3374 ax_simple (expr, aop_sub);
3375 ax_label (expr, i, expr->len);
3379 /* No need to sign extend here. */
3380 ax_const_l (expr, 0);
3381 ax_simple (expr, aop_swap);
3382 ax_simple (expr, aop_sub);
3386 /* Sign extend the operand. */
3387 ax_ext (expr, addr_size_bits);
3388 ax_simple (expr, aop_bit_not);
3391 case DW_OP_plus_uconst:
3392 op_ptr = safe_read_uleb128 (op_ptr, op_end, ®);
3393 /* It would be really weird to emit `DW_OP_plus_uconst 0',
3394 but we micro-optimize anyhow. */
3397 ax_const_l (expr, reg);
3398 ax_simple (expr, aop_add);
3403 ax_simple (expr, aop_bit_and);
3407 /* Sign extend the operands. */
3408 ax_ext (expr, addr_size_bits);
3409 ax_simple (expr, aop_swap);
3410 ax_ext (expr, addr_size_bits);
3411 ax_simple (expr, aop_swap);
3412 ax_simple (expr, aop_div_signed);
3416 ax_simple (expr, aop_sub);
3420 ax_simple (expr, aop_rem_unsigned);
3424 ax_simple (expr, aop_mul);
3428 ax_simple (expr, aop_bit_or);
3432 ax_simple (expr, aop_add);
3436 ax_simple (expr, aop_lsh);
3440 ax_simple (expr, aop_rsh_unsigned);
3444 ax_simple (expr, aop_rsh_signed);
3448 ax_simple (expr, aop_bit_xor);
3452 /* Sign extend the operands. */
3453 ax_ext (expr, addr_size_bits);
3454 ax_simple (expr, aop_swap);
3455 ax_ext (expr, addr_size_bits);
3456 /* Note no swap here: A <= B is !(B < A). */
3457 ax_simple (expr, aop_less_signed);
3458 ax_simple (expr, aop_log_not);
3462 /* Sign extend the operands. */
3463 ax_ext (expr, addr_size_bits);
3464 ax_simple (expr, aop_swap);
3465 ax_ext (expr, addr_size_bits);
3466 ax_simple (expr, aop_swap);
3467 /* A >= B is !(A < B). */
3468 ax_simple (expr, aop_less_signed);
3469 ax_simple (expr, aop_log_not);
3473 /* Sign extend the operands. */
3474 ax_ext (expr, addr_size_bits);
3475 ax_simple (expr, aop_swap);
3476 ax_ext (expr, addr_size_bits);
3477 /* No need for a second swap here. */
3478 ax_simple (expr, aop_equal);
3482 /* Sign extend the operands. */
3483 ax_ext (expr, addr_size_bits);
3484 ax_simple (expr, aop_swap);
3485 ax_ext (expr, addr_size_bits);
3486 ax_simple (expr, aop_swap);
3487 ax_simple (expr, aop_less_signed);
3491 /* Sign extend the operands. */
3492 ax_ext (expr, addr_size_bits);
3493 ax_simple (expr, aop_swap);
3494 ax_ext (expr, addr_size_bits);
3495 /* Note no swap here: A > B is B < A. */
3496 ax_simple (expr, aop_less_signed);
3500 /* Sign extend the operands. */
3501 ax_ext (expr, addr_size_bits);
3502 ax_simple (expr, aop_swap);
3503 ax_ext (expr, addr_size_bits);
3504 /* No need for a swap here. */
3505 ax_simple (expr, aop_equal);
3506 ax_simple (expr, aop_log_not);
3509 case DW_OP_call_frame_cfa:
3512 CORE_ADDR text_offset;
3514 const gdb_byte *cfa_start, *cfa_end;
3516 if (dwarf2_fetch_cfa_info (arch, expr->scope, per_cu,
3518 &text_offset, &cfa_start, &cfa_end))
3521 ax_reg (expr, regnum);
3524 ax_const_l (expr, off);
3525 ax_simple (expr, aop_add);
3530 /* Another expression. */
3531 ax_const_l (expr, text_offset);
3532 dwarf2_compile_expr_to_ax (expr, loc, arch, addr_size,
3533 cfa_start, cfa_end, per_cu);
3536 loc->kind = axs_lvalue_memory;
3540 case DW_OP_GNU_push_tls_address:
3541 case DW_OP_form_tls_address:
3545 case DW_OP_push_object_address:
3550 offset = extract_signed_integer (op_ptr, 2, byte_order);
3552 i = ax_goto (expr, aop_goto);
3553 dw_labels.push_back (op_ptr + offset - base);
3554 patches.push_back (i);
3558 offset = extract_signed_integer (op_ptr, 2, byte_order);
3560 /* Zero extend the operand. */
3561 ax_zero_ext (expr, addr_size_bits);
3562 i = ax_goto (expr, aop_if_goto);
3563 dw_labels.push_back (op_ptr + offset - base);
3564 patches.push_back (i);
3571 case DW_OP_bit_piece:
3573 uint64_t size, offset;
3575 if (op_ptr - 1 == previous_piece)
3576 error (_("Cannot translate empty pieces to agent expressions"));
3577 previous_piece = op_ptr - 1;
3579 op_ptr = safe_read_uleb128 (op_ptr, op_end, &size);
3580 if (op == DW_OP_piece)
3586 op_ptr = safe_read_uleb128 (op_ptr, op_end, &offset);
3588 if (bits_collected + size > 8 * sizeof (LONGEST))
3589 error (_("Expression pieces exceed word size"));
3591 /* Access the bits. */
3594 case axs_lvalue_register:
3595 ax_reg (expr, loc->u.reg);
3598 case axs_lvalue_memory:
3599 /* Offset the pointer, if needed. */
3602 ax_const_l (expr, offset / 8);
3603 ax_simple (expr, aop_add);
3606 access_memory (arch, expr, size);
3610 /* For a bits-big-endian target, shift up what we already
3611 have. For a bits-little-endian target, shift up the
3612 new data. Note that there is a potential bug here if
3613 the DWARF expression leaves multiple values on the
3615 if (bits_collected > 0)
3617 if (bits_big_endian)
3619 ax_simple (expr, aop_swap);
3620 ax_const_l (expr, size);
3621 ax_simple (expr, aop_lsh);
3622 /* We don't need a second swap here, because
3623 aop_bit_or is symmetric. */
3627 ax_const_l (expr, size);
3628 ax_simple (expr, aop_lsh);
3630 ax_simple (expr, aop_bit_or);
3633 bits_collected += size;
3634 loc->kind = axs_rvalue;
3638 case DW_OP_GNU_uninit:
3644 struct dwarf2_locexpr_baton block;
3645 int size = (op == DW_OP_call2 ? 2 : 4);
3647 uoffset = extract_unsigned_integer (op_ptr, size, byte_order);
3650 cu_offset offset = (cu_offset) uoffset;
3651 block = dwarf2_fetch_die_loc_cu_off (offset, per_cu,
3654 /* DW_OP_call_ref is currently not supported. */
3655 gdb_assert (block.per_cu == per_cu);
3657 dwarf2_compile_expr_to_ax (expr, loc, arch, addr_size,
3658 block.data, block.data + block.size,
3663 case DW_OP_call_ref:
3671 /* Patch all the branches we emitted. */
3672 for (i = 0; i < patches.size (); ++i)
3674 int targ = offsets[dw_labels[i]];
3676 internal_error (__FILE__, __LINE__, _("invalid label"));
3677 ax_label (expr, patches[i], targ);
3682 /* Return the value of SYMBOL in FRAME using the DWARF-2 expression
3683 evaluator to calculate the location. */
3684 static struct value *
3685 locexpr_read_variable (struct symbol *symbol, struct frame_info *frame)
3687 struct dwarf2_locexpr_baton *dlbaton
3688 = (struct dwarf2_locexpr_baton *) SYMBOL_LOCATION_BATON (symbol);
3691 val = dwarf2_evaluate_loc_desc (SYMBOL_TYPE (symbol), frame, dlbaton->data,
3692 dlbaton->size, dlbaton->per_cu);
3697 /* Return the value of SYMBOL in FRAME at (callee) FRAME's function
3698 entry. SYMBOL should be a function parameter, otherwise NO_ENTRY_VALUE_ERROR
3701 static struct value *
3702 locexpr_read_variable_at_entry (struct symbol *symbol, struct frame_info *frame)
3704 struct dwarf2_locexpr_baton *dlbaton
3705 = (struct dwarf2_locexpr_baton *) SYMBOL_LOCATION_BATON (symbol);
3707 return value_of_dwarf_block_entry (SYMBOL_TYPE (symbol), frame, dlbaton->data,
3711 /* Implementation of get_symbol_read_needs from
3712 symbol_computed_ops. */
3714 static enum symbol_needs_kind
3715 locexpr_get_symbol_read_needs (struct symbol *symbol)
3717 struct dwarf2_locexpr_baton *dlbaton
3718 = (struct dwarf2_locexpr_baton *) SYMBOL_LOCATION_BATON (symbol);
3720 return dwarf2_loc_desc_get_symbol_read_needs (dlbaton->data, dlbaton->size,
3724 /* Return true if DATA points to the end of a piece. END is one past
3725 the last byte in the expression. */
3728 piece_end_p (const gdb_byte *data, const gdb_byte *end)
3730 return data == end || data[0] == DW_OP_piece || data[0] == DW_OP_bit_piece;
3733 /* Helper for locexpr_describe_location_piece that finds the name of a
3737 locexpr_regname (struct gdbarch *gdbarch, int dwarf_regnum)
3741 /* This doesn't use dwarf_reg_to_regnum_or_error on purpose.
3742 We'd rather print *something* here than throw an error. */
3743 regnum = dwarf_reg_to_regnum (gdbarch, dwarf_regnum);
3744 /* gdbarch_register_name may just return "", return something more
3745 descriptive for bad register numbers. */
3748 /* The text is output as "$bad_register_number".
3749 That is why we use the underscores. */
3750 return _("bad_register_number");
3752 return gdbarch_register_name (gdbarch, regnum);
3755 /* Nicely describe a single piece of a location, returning an updated
3756 position in the bytecode sequence. This function cannot recognize
3757 all locations; if a location is not recognized, it simply returns
3758 DATA. If there is an error during reading, e.g. we run off the end
3759 of the buffer, an error is thrown. */
3761 static const gdb_byte *
3762 locexpr_describe_location_piece (struct symbol *symbol, struct ui_file *stream,
3763 CORE_ADDR addr, struct objfile *objfile,
3764 struct dwarf2_per_cu_data *per_cu,
3765 const gdb_byte *data, const gdb_byte *end,
3766 unsigned int addr_size)
3768 struct gdbarch *gdbarch = get_objfile_arch (objfile);
3771 if (data[0] >= DW_OP_reg0 && data[0] <= DW_OP_reg31)
3773 fprintf_filtered (stream, _("a variable in $%s"),
3774 locexpr_regname (gdbarch, data[0] - DW_OP_reg0));
3777 else if (data[0] == DW_OP_regx)
3781 data = safe_read_uleb128 (data + 1, end, ®);
3782 fprintf_filtered (stream, _("a variable in $%s"),
3783 locexpr_regname (gdbarch, reg));
3785 else if (data[0] == DW_OP_fbreg)
3787 const struct block *b;
3788 struct symbol *framefunc;
3790 int64_t frame_offset;
3791 const gdb_byte *base_data, *new_data, *save_data = data;
3793 int64_t base_offset = 0;
3795 new_data = safe_read_sleb128 (data + 1, end, &frame_offset);
3796 if (!piece_end_p (new_data, end))
3800 b = block_for_pc (addr);
3803 error (_("No block found for address for symbol \"%s\"."),
3804 SYMBOL_PRINT_NAME (symbol));
3806 framefunc = block_linkage_function (b);
3809 error (_("No function found for block for symbol \"%s\"."),
3810 SYMBOL_PRINT_NAME (symbol));
3812 func_get_frame_base_dwarf_block (framefunc, addr, &base_data, &base_size);
3814 if (base_data[0] >= DW_OP_breg0 && base_data[0] <= DW_OP_breg31)
3816 const gdb_byte *buf_end;
3818 frame_reg = base_data[0] - DW_OP_breg0;
3819 buf_end = safe_read_sleb128 (base_data + 1, base_data + base_size,
3821 if (buf_end != base_data + base_size)
3822 error (_("Unexpected opcode after "
3823 "DW_OP_breg%u for symbol \"%s\"."),
3824 frame_reg, SYMBOL_PRINT_NAME (symbol));
3826 else if (base_data[0] >= DW_OP_reg0 && base_data[0] <= DW_OP_reg31)
3828 /* The frame base is just the register, with no offset. */
3829 frame_reg = base_data[0] - DW_OP_reg0;
3834 /* We don't know what to do with the frame base expression,
3835 so we can't trace this variable; give up. */
3839 fprintf_filtered (stream,
3840 _("a variable at frame base reg $%s offset %s+%s"),
3841 locexpr_regname (gdbarch, frame_reg),
3842 plongest (base_offset), plongest (frame_offset));
3844 else if (data[0] >= DW_OP_breg0 && data[0] <= DW_OP_breg31
3845 && piece_end_p (data, end))
3849 data = safe_read_sleb128 (data + 1, end, &offset);
3851 fprintf_filtered (stream,
3852 _("a variable at offset %s from base reg $%s"),
3854 locexpr_regname (gdbarch, data[0] - DW_OP_breg0));
3857 /* The location expression for a TLS variable looks like this (on a
3860 DW_AT_location : 10 byte block: 3 4 0 0 0 0 0 0 0 e0
3861 (DW_OP_addr: 4; DW_OP_GNU_push_tls_address)
3863 0x3 is the encoding for DW_OP_addr, which has an operand as long
3864 as the size of an address on the target machine (here is 8
3865 bytes). Note that more recent version of GCC emit DW_OP_const4u
3866 or DW_OP_const8u, depending on address size, rather than
3867 DW_OP_addr. 0xe0 is the encoding for DW_OP_GNU_push_tls_address.
3868 The operand represents the offset at which the variable is within
3869 the thread local storage. */
3871 else if (data + 1 + addr_size < end
3872 && (data[0] == DW_OP_addr
3873 || (addr_size == 4 && data[0] == DW_OP_const4u)
3874 || (addr_size == 8 && data[0] == DW_OP_const8u))
3875 && (data[1 + addr_size] == DW_OP_GNU_push_tls_address
3876 || data[1 + addr_size] == DW_OP_form_tls_address)
3877 && piece_end_p (data + 2 + addr_size, end))
3880 offset = extract_unsigned_integer (data + 1, addr_size,
3881 gdbarch_byte_order (gdbarch));
3883 fprintf_filtered (stream,
3884 _("a thread-local variable at offset 0x%s "
3885 "in the thread-local storage for `%s'"),
3886 phex_nz (offset, addr_size), objfile_name (objfile));
3888 data += 1 + addr_size + 1;
3891 /* With -gsplit-dwarf a TLS variable can also look like this:
3892 DW_AT_location : 3 byte block: fc 4 e0
3893 (DW_OP_GNU_const_index: 4;
3894 DW_OP_GNU_push_tls_address) */
3895 else if (data + 3 <= end
3896 && data + 1 + (leb128_size = skip_leb128 (data + 1, end)) < end
3897 && data[0] == DW_OP_GNU_const_index
3899 && (data[1 + leb128_size] == DW_OP_GNU_push_tls_address
3900 || data[1 + leb128_size] == DW_OP_form_tls_address)
3901 && piece_end_p (data + 2 + leb128_size, end))
3905 data = safe_read_uleb128 (data + 1, end, &offset);
3906 offset = dwarf2_read_addr_index (per_cu, offset);
3907 fprintf_filtered (stream,
3908 _("a thread-local variable at offset 0x%s "
3909 "in the thread-local storage for `%s'"),
3910 phex_nz (offset, addr_size), objfile_name (objfile));
3914 else if (data[0] >= DW_OP_lit0
3915 && data[0] <= DW_OP_lit31
3917 && data[1] == DW_OP_stack_value)
3919 fprintf_filtered (stream, _("the constant %d"), data[0] - DW_OP_lit0);
3926 /* Disassemble an expression, stopping at the end of a piece or at the
3927 end of the expression. Returns a pointer to the next unread byte
3928 in the input expression. If ALL is nonzero, then this function
3929 will keep going until it reaches the end of the expression.
3930 If there is an error during reading, e.g. we run off the end
3931 of the buffer, an error is thrown. */
3933 static const gdb_byte *
3934 disassemble_dwarf_expression (struct ui_file *stream,
3935 struct gdbarch *arch, unsigned int addr_size,
3936 int offset_size, const gdb_byte *start,
3937 const gdb_byte *data, const gdb_byte *end,
3938 int indent, int all,
3939 struct dwarf2_per_cu_data *per_cu)
3943 || (data[0] != DW_OP_piece && data[0] != DW_OP_bit_piece)))
3945 enum dwarf_location_atom op = (enum dwarf_location_atom) *data++;
3950 name = get_DW_OP_name (op);
3953 error (_("Unrecognized DWARF opcode 0x%02x at %ld"),
3954 op, (long) (data - 1 - start));
3955 fprintf_filtered (stream, " %*ld: %s", indent + 4,
3956 (long) (data - 1 - start), name);
3961 ul = extract_unsigned_integer (data, addr_size,
3962 gdbarch_byte_order (arch));
3964 fprintf_filtered (stream, " 0x%s", phex_nz (ul, addr_size));
3968 ul = extract_unsigned_integer (data, 1, gdbarch_byte_order (arch));
3970 fprintf_filtered (stream, " %s", pulongest (ul));
3973 l = extract_signed_integer (data, 1, gdbarch_byte_order (arch));
3975 fprintf_filtered (stream, " %s", plongest (l));
3978 ul = extract_unsigned_integer (data, 2, gdbarch_byte_order (arch));
3980 fprintf_filtered (stream, " %s", pulongest (ul));
3983 l = extract_signed_integer (data, 2, gdbarch_byte_order (arch));
3985 fprintf_filtered (stream, " %s", plongest (l));
3988 ul = extract_unsigned_integer (data, 4, gdbarch_byte_order (arch));
3990 fprintf_filtered (stream, " %s", pulongest (ul));
3993 l = extract_signed_integer (data, 4, gdbarch_byte_order (arch));
3995 fprintf_filtered (stream, " %s", plongest (l));
3998 ul = extract_unsigned_integer (data, 8, gdbarch_byte_order (arch));
4000 fprintf_filtered (stream, " %s", pulongest (ul));
4003 l = extract_signed_integer (data, 8, gdbarch_byte_order (arch));
4005 fprintf_filtered (stream, " %s", plongest (l));
4008 data = safe_read_uleb128 (data, end, &ul);
4009 fprintf_filtered (stream, " %s", pulongest (ul));
4012 data = safe_read_sleb128 (data, end, &l);
4013 fprintf_filtered (stream, " %s", plongest (l));
4048 fprintf_filtered (stream, " [$%s]",
4049 locexpr_regname (arch, op - DW_OP_reg0));
4053 data = safe_read_uleb128 (data, end, &ul);
4054 fprintf_filtered (stream, " %s [$%s]", pulongest (ul),
4055 locexpr_regname (arch, (int) ul));
4058 case DW_OP_implicit_value:
4059 data = safe_read_uleb128 (data, end, &ul);
4061 fprintf_filtered (stream, " %s", pulongest (ul));
4096 data = safe_read_sleb128 (data, end, &l);
4097 fprintf_filtered (stream, " %s [$%s]", plongest (l),
4098 locexpr_regname (arch, op - DW_OP_breg0));
4102 data = safe_read_uleb128 (data, end, &ul);
4103 data = safe_read_sleb128 (data, end, &l);
4104 fprintf_filtered (stream, " register %s [$%s] offset %s",
4106 locexpr_regname (arch, (int) ul),
4111 data = safe_read_sleb128 (data, end, &l);
4112 fprintf_filtered (stream, " %s", plongest (l));
4115 case DW_OP_xderef_size:
4116 case DW_OP_deref_size:
4118 fprintf_filtered (stream, " %d", *data);
4122 case DW_OP_plus_uconst:
4123 data = safe_read_uleb128 (data, end, &ul);
4124 fprintf_filtered (stream, " %s", pulongest (ul));
4128 l = extract_signed_integer (data, 2, gdbarch_byte_order (arch));
4130 fprintf_filtered (stream, " to %ld",
4131 (long) (data + l - start));
4135 l = extract_signed_integer (data, 2, gdbarch_byte_order (arch));
4137 fprintf_filtered (stream, " %ld",
4138 (long) (data + l - start));
4142 ul = extract_unsigned_integer (data, 2, gdbarch_byte_order (arch));
4144 fprintf_filtered (stream, " offset %s", phex_nz (ul, 2));
4148 ul = extract_unsigned_integer (data, 4, gdbarch_byte_order (arch));
4150 fprintf_filtered (stream, " offset %s", phex_nz (ul, 4));
4153 case DW_OP_call_ref:
4154 ul = extract_unsigned_integer (data, offset_size,
4155 gdbarch_byte_order (arch));
4156 data += offset_size;
4157 fprintf_filtered (stream, " offset %s", phex_nz (ul, offset_size));
4161 data = safe_read_uleb128 (data, end, &ul);
4162 fprintf_filtered (stream, " %s (bytes)", pulongest (ul));
4165 case DW_OP_bit_piece:
4169 data = safe_read_uleb128 (data, end, &ul);
4170 data = safe_read_uleb128 (data, end, &offset);
4171 fprintf_filtered (stream, " size %s offset %s (bits)",
4172 pulongest (ul), pulongest (offset));
4176 case DW_OP_implicit_pointer:
4177 case DW_OP_GNU_implicit_pointer:
4179 ul = extract_unsigned_integer (data, offset_size,
4180 gdbarch_byte_order (arch));
4181 data += offset_size;
4183 data = safe_read_sleb128 (data, end, &l);
4185 fprintf_filtered (stream, " DIE %s offset %s",
4186 phex_nz (ul, offset_size),
4191 case DW_OP_deref_type:
4192 case DW_OP_GNU_deref_type:
4194 int addr_size = *data++;
4197 data = safe_read_uleb128 (data, end, &ul);
4198 cu_offset offset = (cu_offset) ul;
4199 type = dwarf2_get_die_type (offset, per_cu);
4200 fprintf_filtered (stream, "<");
4201 type_print (type, "", stream, -1);
4202 fprintf_filtered (stream, " [0x%s]> %d",
4203 phex_nz (to_underlying (offset), 0),
4208 case DW_OP_const_type:
4209 case DW_OP_GNU_const_type:
4213 data = safe_read_uleb128 (data, end, &ul);
4214 cu_offset type_die = (cu_offset) ul;
4215 type = dwarf2_get_die_type (type_die, per_cu);
4216 fprintf_filtered (stream, "<");
4217 type_print (type, "", stream, -1);
4218 fprintf_filtered (stream, " [0x%s]>",
4219 phex_nz (to_underlying (type_die), 0));
4223 case DW_OP_regval_type:
4224 case DW_OP_GNU_regval_type:
4229 data = safe_read_uleb128 (data, end, ®);
4230 data = safe_read_uleb128 (data, end, &ul);
4231 cu_offset type_die = (cu_offset) ul;
4233 type = dwarf2_get_die_type (type_die, per_cu);
4234 fprintf_filtered (stream, "<");
4235 type_print (type, "", stream, -1);
4236 fprintf_filtered (stream, " [0x%s]> [$%s]",
4237 phex_nz (to_underlying (type_die), 0),
4238 locexpr_regname (arch, reg));
4243 case DW_OP_GNU_convert:
4244 case DW_OP_reinterpret:
4245 case DW_OP_GNU_reinterpret:
4247 data = safe_read_uleb128 (data, end, &ul);
4248 cu_offset type_die = (cu_offset) ul;
4250 if (to_underlying (type_die) == 0)
4251 fprintf_filtered (stream, "<0>");
4256 type = dwarf2_get_die_type (type_die, per_cu);
4257 fprintf_filtered (stream, "<");
4258 type_print (type, "", stream, -1);
4259 fprintf_filtered (stream, " [0x%s]>",
4260 phex_nz (to_underlying (type_die), 0));
4265 case DW_OP_entry_value:
4266 case DW_OP_GNU_entry_value:
4267 data = safe_read_uleb128 (data, end, &ul);
4268 fputc_filtered ('\n', stream);
4269 disassemble_dwarf_expression (stream, arch, addr_size, offset_size,
4270 start, data, data + ul, indent + 2,
4275 case DW_OP_GNU_parameter_ref:
4276 ul = extract_unsigned_integer (data, 4, gdbarch_byte_order (arch));
4278 fprintf_filtered (stream, " offset %s", phex_nz (ul, 4));
4281 case DW_OP_GNU_addr_index:
4282 data = safe_read_uleb128 (data, end, &ul);
4283 ul = dwarf2_read_addr_index (per_cu, ul);
4284 fprintf_filtered (stream, " 0x%s", phex_nz (ul, addr_size));
4286 case DW_OP_GNU_const_index:
4287 data = safe_read_uleb128 (data, end, &ul);
4288 ul = dwarf2_read_addr_index (per_cu, ul);
4289 fprintf_filtered (stream, " %s", pulongest (ul));
4293 fprintf_filtered (stream, "\n");
4299 /* Describe a single location, which may in turn consist of multiple
4303 locexpr_describe_location_1 (struct symbol *symbol, CORE_ADDR addr,
4304 struct ui_file *stream,
4305 const gdb_byte *data, size_t size,
4306 struct objfile *objfile, unsigned int addr_size,
4307 int offset_size, struct dwarf2_per_cu_data *per_cu)
4309 const gdb_byte *end = data + size;
4310 int first_piece = 1, bad = 0;
4314 const gdb_byte *here = data;
4315 int disassemble = 1;
4320 fprintf_filtered (stream, _(", and "));
4322 if (!dwarf_always_disassemble)
4324 data = locexpr_describe_location_piece (symbol, stream,
4325 addr, objfile, per_cu,
4326 data, end, addr_size);
4327 /* If we printed anything, or if we have an empty piece,
4328 then don't disassemble. */
4330 || data[0] == DW_OP_piece
4331 || data[0] == DW_OP_bit_piece)
4336 fprintf_filtered (stream, _("a complex DWARF expression:\n"));
4337 data = disassemble_dwarf_expression (stream,
4338 get_objfile_arch (objfile),
4339 addr_size, offset_size, data,
4341 dwarf_always_disassemble,
4347 int empty = data == here;
4350 fprintf_filtered (stream, " ");
4351 if (data[0] == DW_OP_piece)
4355 data = safe_read_uleb128 (data + 1, end, &bytes);
4358 fprintf_filtered (stream, _("an empty %s-byte piece"),
4361 fprintf_filtered (stream, _(" [%s-byte piece]"),
4364 else if (data[0] == DW_OP_bit_piece)
4366 uint64_t bits, offset;
4368 data = safe_read_uleb128 (data + 1, end, &bits);
4369 data = safe_read_uleb128 (data, end, &offset);
4372 fprintf_filtered (stream,
4373 _("an empty %s-bit piece"),
4376 fprintf_filtered (stream,
4377 _(" [%s-bit piece, offset %s bits]"),
4378 pulongest (bits), pulongest (offset));
4388 if (bad || data > end)
4389 error (_("Corrupted DWARF2 expression for \"%s\"."),
4390 SYMBOL_PRINT_NAME (symbol));
4393 /* Print a natural-language description of SYMBOL to STREAM. This
4394 version is for a symbol with a single location. */
4397 locexpr_describe_location (struct symbol *symbol, CORE_ADDR addr,
4398 struct ui_file *stream)
4400 struct dwarf2_locexpr_baton *dlbaton
4401 = (struct dwarf2_locexpr_baton *) SYMBOL_LOCATION_BATON (symbol);
4402 struct objfile *objfile = dwarf2_per_cu_objfile (dlbaton->per_cu);
4403 unsigned int addr_size = dwarf2_per_cu_addr_size (dlbaton->per_cu);
4404 int offset_size = dwarf2_per_cu_offset_size (dlbaton->per_cu);
4406 locexpr_describe_location_1 (symbol, addr, stream,
4407 dlbaton->data, dlbaton->size,
4408 objfile, addr_size, offset_size,
4412 /* Describe the location of SYMBOL as an agent value in VALUE, generating
4413 any necessary bytecode in AX. */
4416 locexpr_tracepoint_var_ref (struct symbol *symbol, struct gdbarch *gdbarch,
4417 struct agent_expr *ax, struct axs_value *value)
4419 struct dwarf2_locexpr_baton *dlbaton
4420 = (struct dwarf2_locexpr_baton *) SYMBOL_LOCATION_BATON (symbol);
4421 unsigned int addr_size = dwarf2_per_cu_addr_size (dlbaton->per_cu);
4423 if (dlbaton->size == 0)
4424 value->optimized_out = 1;
4426 dwarf2_compile_expr_to_ax (ax, value, gdbarch, addr_size,
4427 dlbaton->data, dlbaton->data + dlbaton->size,
4431 /* symbol_computed_ops 'generate_c_location' method. */
4434 locexpr_generate_c_location (struct symbol *sym, string_file &stream,
4435 struct gdbarch *gdbarch,
4436 unsigned char *registers_used,
4437 CORE_ADDR pc, const char *result_name)
4439 struct dwarf2_locexpr_baton *dlbaton
4440 = (struct dwarf2_locexpr_baton *) SYMBOL_LOCATION_BATON (sym);
4441 unsigned int addr_size = dwarf2_per_cu_addr_size (dlbaton->per_cu);
4443 if (dlbaton->size == 0)
4444 error (_("symbol \"%s\" is optimized out"), SYMBOL_NATURAL_NAME (sym));
4446 compile_dwarf_expr_to_c (stream, result_name,
4447 sym, pc, gdbarch, registers_used, addr_size,
4448 dlbaton->data, dlbaton->data + dlbaton->size,
4452 /* The set of location functions used with the DWARF-2 expression
4454 const struct symbol_computed_ops dwarf2_locexpr_funcs = {
4455 locexpr_read_variable,
4456 locexpr_read_variable_at_entry,
4457 locexpr_get_symbol_read_needs,
4458 locexpr_describe_location,
4459 0, /* location_has_loclist */
4460 locexpr_tracepoint_var_ref,
4461 locexpr_generate_c_location
4465 /* Wrapper functions for location lists. These generally find
4466 the appropriate location expression and call something above. */
4468 /* Return the value of SYMBOL in FRAME using the DWARF-2 expression
4469 evaluator to calculate the location. */
4470 static struct value *
4471 loclist_read_variable (struct symbol *symbol, struct frame_info *frame)
4473 struct dwarf2_loclist_baton *dlbaton
4474 = (struct dwarf2_loclist_baton *) SYMBOL_LOCATION_BATON (symbol);
4476 const gdb_byte *data;
4478 CORE_ADDR pc = frame ? get_frame_address_in_block (frame) : 0;
4480 data = dwarf2_find_location_expression (dlbaton, &size, pc);
4481 val = dwarf2_evaluate_loc_desc (SYMBOL_TYPE (symbol), frame, data, size,
4487 /* Read variable SYMBOL like loclist_read_variable at (callee) FRAME's function
4488 entry. SYMBOL should be a function parameter, otherwise NO_ENTRY_VALUE_ERROR
4491 Function always returns non-NULL value, it may be marked optimized out if
4492 inferior frame information is not available. It throws NO_ENTRY_VALUE_ERROR
4493 if it cannot resolve the parameter for any reason. */
4495 static struct value *
4496 loclist_read_variable_at_entry (struct symbol *symbol, struct frame_info *frame)
4498 struct dwarf2_loclist_baton *dlbaton
4499 = (struct dwarf2_loclist_baton *) SYMBOL_LOCATION_BATON (symbol);
4500 const gdb_byte *data;
4504 if (frame == NULL || !get_frame_func_if_available (frame, &pc))
4505 return allocate_optimized_out_value (SYMBOL_TYPE (symbol));
4507 data = dwarf2_find_location_expression (dlbaton, &size, pc);
4509 return allocate_optimized_out_value (SYMBOL_TYPE (symbol));
4511 return value_of_dwarf_block_entry (SYMBOL_TYPE (symbol), frame, data, size);
4514 /* Implementation of get_symbol_read_needs from
4515 symbol_computed_ops. */
4517 static enum symbol_needs_kind
4518 loclist_symbol_needs (struct symbol *symbol)
4520 /* If there's a location list, then assume we need to have a frame
4521 to choose the appropriate location expression. With tracking of
4522 global variables this is not necessarily true, but such tracking
4523 is disabled in GCC at the moment until we figure out how to
4526 return SYMBOL_NEEDS_FRAME;
4529 /* Print a natural-language description of SYMBOL to STREAM. This
4530 version applies when there is a list of different locations, each
4531 with a specified address range. */
4534 loclist_describe_location (struct symbol *symbol, CORE_ADDR addr,
4535 struct ui_file *stream)
4537 struct dwarf2_loclist_baton *dlbaton
4538 = (struct dwarf2_loclist_baton *) SYMBOL_LOCATION_BATON (symbol);
4539 const gdb_byte *loc_ptr, *buf_end;
4540 struct objfile *objfile = dwarf2_per_cu_objfile (dlbaton->per_cu);
4541 struct gdbarch *gdbarch = get_objfile_arch (objfile);
4542 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
4543 unsigned int addr_size = dwarf2_per_cu_addr_size (dlbaton->per_cu);
4544 int offset_size = dwarf2_per_cu_offset_size (dlbaton->per_cu);
4545 int signed_addr_p = bfd_get_sign_extend_vma (objfile->obfd);
4546 /* Adjust base_address for relocatable objects. */
4547 CORE_ADDR base_offset = dwarf2_per_cu_text_offset (dlbaton->per_cu);
4548 CORE_ADDR base_address = dlbaton->base_address + base_offset;
4551 loc_ptr = dlbaton->data;
4552 buf_end = dlbaton->data + dlbaton->size;
4554 fprintf_filtered (stream, _("multi-location:\n"));
4556 /* Iterate through locations until we run out. */
4559 CORE_ADDR low = 0, high = 0; /* init for gcc -Wall */
4561 enum debug_loc_kind kind;
4562 const gdb_byte *new_ptr = NULL; /* init for gcc -Wall */
4564 if (dlbaton->from_dwo)
4565 kind = decode_debug_loc_dwo_addresses (dlbaton->per_cu,
4566 loc_ptr, buf_end, &new_ptr,
4567 &low, &high, byte_order);
4569 kind = decode_debug_loc_addresses (loc_ptr, buf_end, &new_ptr,
4571 byte_order, addr_size,
4576 case DEBUG_LOC_END_OF_LIST:
4579 case DEBUG_LOC_BASE_ADDRESS:
4580 base_address = high + base_offset;
4581 fprintf_filtered (stream, _(" Base address %s"),
4582 paddress (gdbarch, base_address));
4584 case DEBUG_LOC_START_END:
4585 case DEBUG_LOC_START_LENGTH:
4587 case DEBUG_LOC_BUFFER_OVERFLOW:
4588 case DEBUG_LOC_INVALID_ENTRY:
4589 error (_("Corrupted DWARF expression for symbol \"%s\"."),
4590 SYMBOL_PRINT_NAME (symbol));
4592 gdb_assert_not_reached ("bad debug_loc_kind");
4595 /* Otherwise, a location expression entry. */
4596 low += base_address;
4597 high += base_address;
4599 low = gdbarch_adjust_dwarf2_addr (gdbarch, low);
4600 high = gdbarch_adjust_dwarf2_addr (gdbarch, high);
4602 length = extract_unsigned_integer (loc_ptr, 2, byte_order);
4605 /* (It would improve readability to print only the minimum
4606 necessary digits of the second number of the range.) */
4607 fprintf_filtered (stream, _(" Range %s-%s: "),
4608 paddress (gdbarch, low), paddress (gdbarch, high));
4610 /* Now describe this particular location. */
4611 locexpr_describe_location_1 (symbol, low, stream, loc_ptr, length,
4612 objfile, addr_size, offset_size,
4615 fprintf_filtered (stream, "\n");
4621 /* Describe the location of SYMBOL as an agent value in VALUE, generating
4622 any necessary bytecode in AX. */
4624 loclist_tracepoint_var_ref (struct symbol *symbol, struct gdbarch *gdbarch,
4625 struct agent_expr *ax, struct axs_value *value)
4627 struct dwarf2_loclist_baton *dlbaton
4628 = (struct dwarf2_loclist_baton *) SYMBOL_LOCATION_BATON (symbol);
4629 const gdb_byte *data;
4631 unsigned int addr_size = dwarf2_per_cu_addr_size (dlbaton->per_cu);
4633 data = dwarf2_find_location_expression (dlbaton, &size, ax->scope);
4635 value->optimized_out = 1;
4637 dwarf2_compile_expr_to_ax (ax, value, gdbarch, addr_size, data, data + size,
4641 /* symbol_computed_ops 'generate_c_location' method. */
4644 loclist_generate_c_location (struct symbol *sym, string_file &stream,
4645 struct gdbarch *gdbarch,
4646 unsigned char *registers_used,
4647 CORE_ADDR pc, const char *result_name)
4649 struct dwarf2_loclist_baton *dlbaton
4650 = (struct dwarf2_loclist_baton *) SYMBOL_LOCATION_BATON (sym);
4651 unsigned int addr_size = dwarf2_per_cu_addr_size (dlbaton->per_cu);
4652 const gdb_byte *data;
4655 data = dwarf2_find_location_expression (dlbaton, &size, pc);
4657 error (_("symbol \"%s\" is optimized out"), SYMBOL_NATURAL_NAME (sym));
4659 compile_dwarf_expr_to_c (stream, result_name,
4660 sym, pc, gdbarch, registers_used, addr_size,
4665 /* The set of location functions used with the DWARF-2 expression
4666 evaluator and location lists. */
4667 const struct symbol_computed_ops dwarf2_loclist_funcs = {
4668 loclist_read_variable,
4669 loclist_read_variable_at_entry,
4670 loclist_symbol_needs,
4671 loclist_describe_location,
4672 1, /* location_has_loclist */
4673 loclist_tracepoint_var_ref,
4674 loclist_generate_c_location
4677 /* Provide a prototype to silence -Wmissing-prototypes. */
4678 extern initialize_file_ftype _initialize_dwarf2loc;
4681 _initialize_dwarf2loc (void)
4683 add_setshow_zuinteger_cmd ("entry-values", class_maintenance,
4684 &entry_values_debug,
4685 _("Set entry values and tail call frames "
4687 _("Show entry values and tail call frames "
4689 _("When non-zero, the process of determining "
4690 "parameter values from function entry point "
4691 "and tail call frames will be printed."),
4693 show_entry_values_debug,
4694 &setdebuglist, &showdebuglist);
4697 register_self_test (selftests::copy_bitwise_tests);