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 target address size, used only for DWARF_VALUE_STACK. */
1492 /* The pieces themselves. */
1493 struct dwarf_expr_piece *pieces;
1495 /* Frame ID of frame to which a register value is relative, used
1496 only by DWARF_VALUE_REGISTER. */
1497 struct frame_id frame_id;
1500 /* Allocate a closure for a value formed from separately-described
1503 static struct piece_closure *
1504 allocate_piece_closure (struct dwarf2_per_cu_data *per_cu,
1505 int n_pieces, struct dwarf_expr_piece *pieces,
1506 int addr_size, struct frame_info *frame)
1508 struct piece_closure *c = XCNEW (struct piece_closure);
1513 c->n_pieces = n_pieces;
1514 c->addr_size = addr_size;
1515 c->pieces = XCNEWVEC (struct dwarf_expr_piece, n_pieces);
1517 c->frame_id = null_frame_id;
1519 c->frame_id = get_frame_id (frame);
1521 memcpy (c->pieces, pieces, n_pieces * sizeof (struct dwarf_expr_piece));
1522 for (i = 0; i < n_pieces; ++i)
1523 if (c->pieces[i].location == DWARF_VALUE_STACK)
1524 value_incref (c->pieces[i].v.value);
1529 /* Copy NBITS bits from SOURCE to DEST starting at the given bit
1530 offsets. Use the bit order as specified by BITS_BIG_ENDIAN.
1531 Source and destination buffers must not overlap. */
1534 copy_bitwise (gdb_byte *dest, ULONGEST dest_offset,
1535 const gdb_byte *source, ULONGEST source_offset,
1536 ULONGEST nbits, int bits_big_endian)
1538 unsigned int buf, avail;
1543 if (bits_big_endian)
1545 /* Start from the end, then work backwards. */
1546 dest_offset += nbits - 1;
1547 dest += dest_offset / 8;
1548 dest_offset = 7 - dest_offset % 8;
1549 source_offset += nbits - 1;
1550 source += source_offset / 8;
1551 source_offset = 7 - source_offset % 8;
1555 dest += dest_offset / 8;
1557 source += source_offset / 8;
1561 /* Fill BUF with DEST_OFFSET bits from the destination and 8 -
1562 SOURCE_OFFSET bits from the source. */
1563 buf = *(bits_big_endian ? source-- : source++) >> source_offset;
1564 buf <<= dest_offset;
1565 buf |= *dest & ((1 << dest_offset) - 1);
1567 /* NBITS: bits yet to be written; AVAIL: BUF's fill level. */
1568 nbits += dest_offset;
1569 avail = dest_offset + 8 - source_offset;
1571 /* Flush 8 bits from BUF, if appropriate. */
1572 if (nbits >= 8 && avail >= 8)
1574 *(bits_big_endian ? dest-- : dest++) = buf;
1580 /* Copy the middle part. */
1583 size_t len = nbits / 8;
1585 /* Use a faster method for byte-aligned copies. */
1588 if (bits_big_endian)
1592 memcpy (dest + 1, source + 1, len);
1596 memcpy (dest, source, len);
1605 buf |= *(bits_big_endian ? source-- : source++) << avail;
1606 *(bits_big_endian ? dest-- : dest++) = buf;
1613 /* Write the last byte. */
1617 buf |= *source << avail;
1619 buf &= (1 << nbits) - 1;
1620 *dest = (*dest & (~0 << nbits)) | buf;
1626 namespace selftests {
1628 /* Helper function for the unit test of copy_bitwise. Convert NBITS bits
1629 out of BITS, starting at OFFS, to the respective '0'/'1'-string. MSB0
1630 specifies whether to assume big endian bit numbering. Store the
1631 resulting (not null-terminated) string at STR. */
1634 bits_to_str (char *str, const gdb_byte *bits, ULONGEST offs,
1635 ULONGEST nbits, int msb0)
1640 for (i = offs / 8, j = offs % 8; nbits; i++, j = 0)
1642 unsigned int ch = bits[i];
1643 for (; j < 8 && nbits; j++, nbits--)
1644 *str++ = (ch & (msb0 ? (1 << (7 - j)) : (1 << j))) ? '1' : '0';
1648 /* Check one invocation of copy_bitwise with the given parameters. */
1651 check_copy_bitwise (const gdb_byte *dest, unsigned int dest_offset,
1652 const gdb_byte *source, unsigned int source_offset,
1653 unsigned int nbits, int msb0)
1655 size_t len = align_up (dest_offset + nbits, 8);
1656 char *expected = (char *) alloca (len + 1);
1657 char *actual = (char *) alloca (len + 1);
1658 gdb_byte *buf = (gdb_byte *) alloca (len / 8);
1660 /* Compose a '0'/'1'-string that represents the expected result of
1662 Bits from [0, DEST_OFFSET) are filled from DEST.
1663 Bits from [DEST_OFFSET, DEST_OFFSET + NBITS) are filled from SOURCE.
1664 Bits from [DEST_OFFSET + NBITS, LEN) are filled from DEST.
1673 We should end up with:
1675 DDDDSSDD (D=dest, S=source)
1677 bits_to_str (expected, dest, 0, len, msb0);
1678 bits_to_str (expected + dest_offset, source, source_offset, nbits, msb0);
1680 /* Fill BUF with data from DEST, apply copy_bitwise, and convert the
1681 result to a '0'/'1'-string. */
1682 memcpy (buf, dest, len / 8);
1683 copy_bitwise (buf, dest_offset, source, source_offset, nbits, msb0);
1684 bits_to_str (actual, buf, 0, len, msb0);
1686 /* Compare the resulting strings. */
1687 expected[len] = actual[len] = '\0';
1688 if (strcmp (expected, actual) != 0)
1689 error (_("copy_bitwise %s != %s (%u+%u -> %u)"),
1690 expected, actual, source_offset, nbits, dest_offset);
1693 /* Unit test for copy_bitwise. */
1696 copy_bitwise_tests (void)
1698 /* Data to be used as both source and destination buffers. The two
1699 arrays below represent the lsb0- and msb0- encoded versions of the
1700 following bit string, respectively:
1701 00000000 00011111 11111111 01001000 10100101 11110010
1702 This pattern is chosen such that it contains:
1703 - constant 0- and 1- chunks of more than a full byte;
1704 - 0/1- and 1/0 transitions on all bit positions within a byte;
1705 - several sufficiently asymmetric bytes.
1707 static const gdb_byte data_lsb0[] = {
1708 0x00, 0xf8, 0xff, 0x12, 0xa5, 0x4f
1710 static const gdb_byte data_msb0[] = {
1711 0x00, 0x1f, 0xff, 0x48, 0xa5, 0xf2
1714 constexpr size_t data_nbits = 8 * sizeof (data_lsb0);
1715 constexpr unsigned max_nbits = 24;
1717 /* Try all combinations of:
1718 lsb0/msb0 bit order (using the respective data array)
1719 X [0, MAX_NBITS] copy bit width
1720 X feasible source offsets for the given copy bit width
1721 X feasible destination offsets
1723 for (int msb0 = 0; msb0 < 2; msb0++)
1725 const gdb_byte *data = msb0 ? data_msb0 : data_lsb0;
1727 for (unsigned int nbits = 1; nbits <= max_nbits; nbits++)
1729 const unsigned int max_offset = data_nbits - nbits;
1731 for (unsigned source_offset = 0;
1732 source_offset <= max_offset;
1735 for (unsigned dest_offset = 0;
1736 dest_offset <= max_offset;
1739 check_copy_bitwise (data + dest_offset / 8,
1741 data + source_offset / 8,
1748 /* Special cases: copy all, copy nothing. */
1749 check_copy_bitwise (data_lsb0, 0, data_msb0, 0, data_nbits, msb0);
1750 check_copy_bitwise (data_msb0, 0, data_lsb0, 0, data_nbits, msb0);
1751 check_copy_bitwise (data, data_nbits - 7, data, 9, 0, msb0);
1755 } /* namespace selftests */
1757 #endif /* GDB_SELF_TEST */
1760 read_pieced_value (struct value *v)
1764 ULONGEST bits_to_skip;
1766 struct piece_closure *c
1767 = (struct piece_closure *) value_computed_closure (v);
1769 size_t buffer_size = 0;
1770 std::vector<gdb_byte> buffer;
1772 = gdbarch_bits_big_endian (get_type_arch (value_type (v)));
1774 if (value_type (v) != value_enclosing_type (v))
1775 internal_error (__FILE__, __LINE__,
1776 _("Should not be able to create a lazy value with "
1777 "an enclosing type"));
1779 contents = value_contents_raw (v);
1780 bits_to_skip = 8 * value_offset (v);
1781 if (value_bitsize (v))
1783 bits_to_skip += value_bitpos (v);
1784 type_len = value_bitsize (v);
1787 type_len = 8 * TYPE_LENGTH (value_type (v));
1789 for (i = 0; i < c->n_pieces && offset < type_len; i++)
1791 struct dwarf_expr_piece *p = &c->pieces[i];
1792 size_t this_size, this_size_bits;
1793 long dest_offset_bits, source_offset_bits, source_offset;
1794 const gdb_byte *intermediate_buffer;
1796 /* Compute size, source, and destination offsets for copying, in
1798 this_size_bits = p->size;
1799 if (bits_to_skip > 0 && bits_to_skip >= this_size_bits)
1801 bits_to_skip -= this_size_bits;
1804 if (bits_to_skip > 0)
1806 dest_offset_bits = 0;
1807 source_offset_bits = bits_to_skip;
1808 this_size_bits -= bits_to_skip;
1813 dest_offset_bits = offset;
1814 source_offset_bits = 0;
1816 if (this_size_bits > type_len - offset)
1817 this_size_bits = type_len - offset;
1819 this_size = (this_size_bits + source_offset_bits % 8 + 7) / 8;
1820 source_offset = source_offset_bits / 8;
1821 if (buffer_size < this_size)
1823 buffer_size = this_size;
1824 buffer.reserve (buffer_size);
1826 intermediate_buffer = buffer.data ();
1828 /* Copy from the source to DEST_BUFFER. */
1829 switch (p->location)
1831 case DWARF_VALUE_REGISTER:
1833 struct frame_info *frame = frame_find_by_id (c->frame_id);
1834 struct gdbarch *arch = get_frame_arch (frame);
1835 int gdb_regnum = dwarf_reg_to_regnum_or_error (arch, p->v.regno);
1837 LONGEST reg_offset = source_offset;
1839 if (gdbarch_byte_order (arch) == BFD_ENDIAN_BIG
1840 && this_size < register_size (arch, gdb_regnum))
1842 /* Big-endian, and we want less than full size. */
1843 reg_offset = register_size (arch, gdb_regnum) - this_size;
1844 /* We want the lower-order THIS_SIZE_BITS of the bytes
1845 we extract from the register. */
1846 source_offset_bits += 8 * this_size - this_size_bits;
1849 if (!get_frame_register_bytes (frame, gdb_regnum, reg_offset,
1850 this_size, buffer.data (),
1853 /* Just so garbage doesn't ever shine through. */
1854 memset (buffer.data (), 0, this_size);
1857 mark_value_bits_optimized_out (v, offset, this_size_bits);
1859 mark_value_bits_unavailable (v, offset, this_size_bits);
1864 case DWARF_VALUE_MEMORY:
1865 read_value_memory (v, offset,
1866 p->v.mem.in_stack_memory,
1867 p->v.mem.addr + source_offset,
1868 buffer.data (), this_size);
1871 case DWARF_VALUE_STACK:
1873 size_t n = this_size;
1875 if (n > c->addr_size - source_offset)
1876 n = (c->addr_size >= source_offset
1877 ? c->addr_size - source_offset
1885 const gdb_byte *val_bytes = value_contents_all (p->v.value);
1887 intermediate_buffer = val_bytes + source_offset;
1892 case DWARF_VALUE_LITERAL:
1894 size_t n = this_size;
1896 if (n > p->v.literal.length - source_offset)
1897 n = (p->v.literal.length >= source_offset
1898 ? p->v.literal.length - source_offset
1901 intermediate_buffer = p->v.literal.data + source_offset;
1905 /* These bits show up as zeros -- but do not cause the value
1906 to be considered optimized-out. */
1907 case DWARF_VALUE_IMPLICIT_POINTER:
1910 case DWARF_VALUE_OPTIMIZED_OUT:
1911 mark_value_bits_optimized_out (v, offset, this_size_bits);
1915 internal_error (__FILE__, __LINE__, _("invalid location type"));
1918 if (p->location != DWARF_VALUE_OPTIMIZED_OUT
1919 && p->location != DWARF_VALUE_IMPLICIT_POINTER)
1920 copy_bitwise (contents, dest_offset_bits,
1921 intermediate_buffer, source_offset_bits % 8,
1922 this_size_bits, bits_big_endian);
1924 offset += this_size_bits;
1929 write_pieced_value (struct value *to, struct value *from)
1933 ULONGEST bits_to_skip;
1934 const gdb_byte *contents;
1935 struct piece_closure *c
1936 = (struct piece_closure *) value_computed_closure (to);
1938 size_t buffer_size = 0;
1939 std::vector<gdb_byte> buffer;
1941 = gdbarch_bits_big_endian (get_type_arch (value_type (to)));
1943 contents = value_contents (from);
1944 bits_to_skip = 8 * value_offset (to);
1945 if (value_bitsize (to))
1947 bits_to_skip += value_bitpos (to);
1948 type_len = value_bitsize (to);
1951 type_len = 8 * TYPE_LENGTH (value_type (to));
1953 for (i = 0; i < c->n_pieces && offset < type_len; i++)
1955 struct dwarf_expr_piece *p = &c->pieces[i];
1956 size_t this_size_bits, this_size;
1957 long dest_offset_bits, source_offset_bits, dest_offset, source_offset;
1959 const gdb_byte *source_buffer;
1961 this_size_bits = p->size;
1962 if (bits_to_skip > 0 && bits_to_skip >= this_size_bits)
1964 bits_to_skip -= this_size_bits;
1967 if (this_size_bits > type_len - offset)
1968 this_size_bits = type_len - offset;
1969 if (bits_to_skip > 0)
1971 dest_offset_bits = bits_to_skip;
1972 source_offset_bits = 0;
1973 this_size_bits -= bits_to_skip;
1978 dest_offset_bits = 0;
1979 source_offset_bits = offset;
1982 this_size = (this_size_bits + source_offset_bits % 8 + 7) / 8;
1983 source_offset = source_offset_bits / 8;
1984 dest_offset = dest_offset_bits / 8;
1985 if (dest_offset_bits % 8 == 0 && source_offset_bits % 8 == 0)
1987 source_buffer = contents + source_offset;
1992 if (buffer_size < this_size)
1994 buffer_size = this_size;
1995 buffer.reserve (buffer_size);
1997 source_buffer = buffer.data ();
2001 switch (p->location)
2003 case DWARF_VALUE_REGISTER:
2005 struct frame_info *frame = frame_find_by_id (c->frame_id);
2006 struct gdbarch *arch = get_frame_arch (frame);
2007 int gdb_regnum = dwarf_reg_to_regnum_or_error (arch, p->v.regno);
2008 int reg_offset = dest_offset;
2010 if (gdbarch_byte_order (arch) == BFD_ENDIAN_BIG
2011 && this_size <= register_size (arch, gdb_regnum))
2013 /* Big-endian, and we want less than full size. */
2014 reg_offset = register_size (arch, gdb_regnum) - this_size;
2021 if (!get_frame_register_bytes (frame, gdb_regnum, reg_offset,
2022 this_size, buffer.data (),
2026 throw_error (OPTIMIZED_OUT_ERROR,
2027 _("Can't do read-modify-write to "
2028 "update bitfield; containing word "
2029 "has been optimized out"));
2031 throw_error (NOT_AVAILABLE_ERROR,
2032 _("Can't do read-modify-write to update "
2033 "bitfield; containing word "
2036 copy_bitwise (buffer.data (), dest_offset_bits,
2037 contents, source_offset_bits,
2042 put_frame_register_bytes (frame, gdb_regnum, reg_offset,
2043 this_size, source_buffer);
2046 case DWARF_VALUE_MEMORY:
2049 /* Only the first and last bytes can possibly have any
2051 read_memory (p->v.mem.addr + dest_offset, buffer.data (), 1);
2052 read_memory (p->v.mem.addr + dest_offset + this_size - 1,
2053 &buffer[this_size - 1], 1);
2054 copy_bitwise (buffer.data (), dest_offset_bits,
2055 contents, source_offset_bits,
2060 write_memory (p->v.mem.addr + dest_offset,
2061 source_buffer, this_size);
2064 mark_value_bytes_optimized_out (to, 0, TYPE_LENGTH (value_type (to)));
2067 offset += this_size_bits;
2071 /* An implementation of an lval_funcs method to see whether a value is
2072 a synthetic pointer. */
2075 check_pieced_synthetic_pointer (const struct value *value, LONGEST bit_offset,
2078 struct piece_closure *c
2079 = (struct piece_closure *) value_computed_closure (value);
2082 bit_offset += 8 * value_offset (value);
2083 if (value_bitsize (value))
2084 bit_offset += value_bitpos (value);
2086 for (i = 0; i < c->n_pieces && bit_length > 0; i++)
2088 struct dwarf_expr_piece *p = &c->pieces[i];
2089 size_t this_size_bits = p->size;
2093 if (bit_offset >= this_size_bits)
2095 bit_offset -= this_size_bits;
2099 bit_length -= this_size_bits - bit_offset;
2103 bit_length -= this_size_bits;
2105 if (p->location != DWARF_VALUE_IMPLICIT_POINTER)
2112 /* A wrapper function for get_frame_address_in_block. */
2115 get_frame_address_in_block_wrapper (void *baton)
2117 return get_frame_address_in_block ((struct frame_info *) baton);
2120 /* Fetch a DW_AT_const_value through a synthetic pointer. */
2122 static struct value *
2123 fetch_const_value_from_synthetic_pointer (sect_offset die, LONGEST byte_offset,
2124 struct dwarf2_per_cu_data *per_cu,
2127 struct value *result = NULL;
2128 struct obstack temp_obstack;
2129 struct cleanup *cleanup;
2130 const gdb_byte *bytes;
2133 obstack_init (&temp_obstack);
2134 cleanup = make_cleanup_obstack_free (&temp_obstack);
2135 bytes = dwarf2_fetch_constant_bytes (die, per_cu, &temp_obstack, &len);
2139 if (byte_offset >= 0
2140 && byte_offset + TYPE_LENGTH (TYPE_TARGET_TYPE (type)) <= len)
2142 bytes += byte_offset;
2143 result = value_from_contents (TYPE_TARGET_TYPE (type), bytes);
2146 invalid_synthetic_pointer ();
2149 result = allocate_optimized_out_value (TYPE_TARGET_TYPE (type));
2151 do_cleanups (cleanup);
2156 /* Fetch the value pointed to by a synthetic pointer. */
2158 static struct value *
2159 indirect_synthetic_pointer (sect_offset die, LONGEST byte_offset,
2160 struct dwarf2_per_cu_data *per_cu,
2161 struct frame_info *frame, struct type *type)
2163 /* Fetch the location expression of the DIE we're pointing to. */
2164 struct dwarf2_locexpr_baton baton
2165 = dwarf2_fetch_die_loc_sect_off (die, per_cu,
2166 get_frame_address_in_block_wrapper, frame);
2168 /* Get type of pointed-to DIE. */
2169 struct type *orig_type = dwarf2_fetch_die_type_sect_off (die, per_cu);
2170 if (orig_type == NULL)
2171 invalid_synthetic_pointer ();
2173 /* If pointed-to DIE has a DW_AT_location, evaluate it and return the
2174 resulting value. Otherwise, it may have a DW_AT_const_value instead,
2175 or it may've been optimized out. */
2176 if (baton.data != NULL)
2177 return dwarf2_evaluate_loc_desc_full (orig_type, frame, baton.data,
2178 baton.size, baton.per_cu,
2179 TYPE_TARGET_TYPE (type),
2182 return fetch_const_value_from_synthetic_pointer (die, byte_offset, per_cu,
2186 /* An implementation of an lval_funcs method to indirect through a
2187 pointer. This handles the synthetic pointer case when needed. */
2189 static struct value *
2190 indirect_pieced_value (struct value *value)
2192 struct piece_closure *c
2193 = (struct piece_closure *) value_computed_closure (value);
2195 struct frame_info *frame;
2196 struct dwarf2_locexpr_baton baton;
2199 struct dwarf_expr_piece *piece = NULL;
2200 LONGEST byte_offset;
2201 enum bfd_endian byte_order;
2203 type = check_typedef (value_type (value));
2204 if (TYPE_CODE (type) != TYPE_CODE_PTR)
2207 bit_length = 8 * TYPE_LENGTH (type);
2208 bit_offset = 8 * value_offset (value);
2209 if (value_bitsize (value))
2210 bit_offset += value_bitpos (value);
2212 for (i = 0; i < c->n_pieces && bit_length > 0; i++)
2214 struct dwarf_expr_piece *p = &c->pieces[i];
2215 size_t this_size_bits = p->size;
2219 if (bit_offset >= this_size_bits)
2221 bit_offset -= this_size_bits;
2225 bit_length -= this_size_bits - bit_offset;
2229 bit_length -= this_size_bits;
2231 if (p->location != DWARF_VALUE_IMPLICIT_POINTER)
2234 if (bit_length != 0)
2235 error (_("Invalid use of DW_OP_implicit_pointer"));
2241 gdb_assert (piece != NULL);
2242 frame = get_selected_frame (_("No frame selected."));
2244 /* This is an offset requested by GDB, such as value subscripts.
2245 However, due to how synthetic pointers are implemented, this is
2246 always presented to us as a pointer type. This means we have to
2247 sign-extend it manually as appropriate. Use raw
2248 extract_signed_integer directly rather than value_as_address and
2249 sign extend afterwards on architectures that would need it
2250 (mostly everywhere except MIPS, which has signed addresses) as
2251 the later would go through gdbarch_pointer_to_address and thus
2252 return a CORE_ADDR with high bits set on architectures that
2253 encode address spaces and other things in CORE_ADDR. */
2254 byte_order = gdbarch_byte_order (get_frame_arch (frame));
2255 byte_offset = extract_signed_integer (value_contents (value),
2256 TYPE_LENGTH (type), byte_order);
2257 byte_offset += piece->v.ptr.offset;
2259 return indirect_synthetic_pointer (piece->v.ptr.die_sect_off,
2260 byte_offset, c->per_cu,
2264 /* Implementation of the coerce_ref method of lval_funcs for synthetic C++
2267 static struct value *
2268 coerce_pieced_ref (const struct value *value)
2270 struct type *type = check_typedef (value_type (value));
2272 if (value_bits_synthetic_pointer (value, value_embedded_offset (value),
2273 TARGET_CHAR_BIT * TYPE_LENGTH (type)))
2275 const struct piece_closure *closure
2276 = (struct piece_closure *) value_computed_closure (value);
2277 struct frame_info *frame
2278 = get_selected_frame (_("No frame selected."));
2280 /* gdb represents synthetic pointers as pieced values with a single
2282 gdb_assert (closure != NULL);
2283 gdb_assert (closure->n_pieces == 1);
2285 return indirect_synthetic_pointer (closure->pieces->v.ptr.die_sect_off,
2286 closure->pieces->v.ptr.offset,
2287 closure->per_cu, frame, type);
2291 /* Else: not a synthetic reference; do nothing. */
2297 copy_pieced_value_closure (const struct value *v)
2299 struct piece_closure *c
2300 = (struct piece_closure *) value_computed_closure (v);
2307 free_pieced_value_closure (struct value *v)
2309 struct piece_closure *c
2310 = (struct piece_closure *) value_computed_closure (v);
2317 for (i = 0; i < c->n_pieces; ++i)
2318 if (c->pieces[i].location == DWARF_VALUE_STACK)
2319 value_free (c->pieces[i].v.value);
2326 /* Functions for accessing a variable described by DW_OP_piece. */
2327 static const struct lval_funcs pieced_value_funcs = {
2330 indirect_pieced_value,
2332 check_pieced_synthetic_pointer,
2333 copy_pieced_value_closure,
2334 free_pieced_value_closure
2337 /* Evaluate a location description, starting at DATA and with length
2338 SIZE, to find the current location of variable of TYPE in the
2339 context of FRAME. If SUBOBJ_TYPE is non-NULL, return instead the
2340 location of the subobject of type SUBOBJ_TYPE at byte offset
2341 SUBOBJ_BYTE_OFFSET within the variable of type TYPE. */
2343 static struct value *
2344 dwarf2_evaluate_loc_desc_full (struct type *type, struct frame_info *frame,
2345 const gdb_byte *data, size_t size,
2346 struct dwarf2_per_cu_data *per_cu,
2347 struct type *subobj_type,
2348 LONGEST subobj_byte_offset)
2350 struct value *retval;
2351 struct objfile *objfile = dwarf2_per_cu_objfile (per_cu);
2353 if (subobj_type == NULL)
2356 subobj_byte_offset = 0;
2358 else if (subobj_byte_offset < 0)
2359 invalid_synthetic_pointer ();
2362 return allocate_optimized_out_value (subobj_type);
2364 dwarf_evaluate_loc_desc ctx;
2366 ctx.per_cu = per_cu;
2367 ctx.obj_address = 0;
2369 scoped_value_mark free_values;
2371 ctx.gdbarch = get_objfile_arch (objfile);
2372 ctx.addr_size = dwarf2_per_cu_addr_size (per_cu);
2373 ctx.ref_addr_size = dwarf2_per_cu_ref_addr_size (per_cu);
2374 ctx.offset = dwarf2_per_cu_text_offset (per_cu);
2378 ctx.eval (data, size);
2380 CATCH (ex, RETURN_MASK_ERROR)
2382 if (ex.error == NOT_AVAILABLE_ERROR)
2384 free_values.free_to_mark ();
2385 retval = allocate_value (subobj_type);
2386 mark_value_bytes_unavailable (retval, 0,
2387 TYPE_LENGTH (subobj_type));
2390 else if (ex.error == NO_ENTRY_VALUE_ERROR)
2392 if (entry_values_debug)
2393 exception_print (gdb_stdout, ex);
2394 free_values.free_to_mark ();
2395 return allocate_optimized_out_value (subobj_type);
2398 throw_exception (ex);
2402 if (ctx.num_pieces > 0)
2404 struct piece_closure *c;
2405 ULONGEST bit_size = 0;
2408 for (i = 0; i < ctx.num_pieces; ++i)
2409 bit_size += ctx.pieces[i].size;
2410 if (8 * (subobj_byte_offset + TYPE_LENGTH (subobj_type)) > bit_size)
2411 invalid_synthetic_pointer ();
2413 c = allocate_piece_closure (per_cu, ctx.num_pieces, ctx.pieces,
2414 ctx.addr_size, frame);
2415 /* We must clean up the value chain after creating the piece
2416 closure but before allocating the result. */
2417 free_values.free_to_mark ();
2418 retval = allocate_computed_value (subobj_type,
2419 &pieced_value_funcs, c);
2420 set_value_offset (retval, subobj_byte_offset);
2424 switch (ctx.location)
2426 case DWARF_VALUE_REGISTER:
2428 struct gdbarch *arch = get_frame_arch (frame);
2430 = longest_to_int (value_as_long (ctx.fetch (0)));
2431 int gdb_regnum = dwarf_reg_to_regnum_or_error (arch, dwarf_regnum);
2433 if (subobj_byte_offset != 0)
2434 error (_("cannot use offset on synthetic pointer to register"));
2435 free_values.free_to_mark ();
2436 retval = value_from_register (subobj_type, gdb_regnum, frame);
2437 if (value_optimized_out (retval))
2441 /* This means the register has undefined value / was
2442 not saved. As we're computing the location of some
2443 variable etc. in the program, not a value for
2444 inspecting a register ($pc, $sp, etc.), return a
2445 generic optimized out value instead, so that we show
2446 <optimized out> instead of <not saved>. */
2447 tmp = allocate_value (subobj_type);
2448 value_contents_copy (tmp, 0, retval, 0,
2449 TYPE_LENGTH (subobj_type));
2455 case DWARF_VALUE_MEMORY:
2457 struct type *ptr_type;
2458 CORE_ADDR address = ctx.fetch_address (0);
2459 int in_stack_memory = ctx.fetch_in_stack_memory (0);
2461 /* DW_OP_deref_size (and possibly other operations too) may
2462 create a pointer instead of an address. Ideally, the
2463 pointer to address conversion would be performed as part
2464 of those operations, but the type of the object to
2465 which the address refers is not known at the time of
2466 the operation. Therefore, we do the conversion here
2467 since the type is readily available. */
2469 switch (TYPE_CODE (subobj_type))
2471 case TYPE_CODE_FUNC:
2472 case TYPE_CODE_METHOD:
2473 ptr_type = builtin_type (ctx.gdbarch)->builtin_func_ptr;
2476 ptr_type = builtin_type (ctx.gdbarch)->builtin_data_ptr;
2479 address = value_as_address (value_from_pointer (ptr_type, address));
2481 free_values.free_to_mark ();
2482 retval = value_at_lazy (subobj_type,
2483 address + subobj_byte_offset);
2484 if (in_stack_memory)
2485 set_value_stack (retval, 1);
2489 case DWARF_VALUE_STACK:
2491 struct value *value = ctx.fetch (0);
2492 size_t n = TYPE_LENGTH (value_type (value));
2493 size_t len = TYPE_LENGTH (subobj_type);
2494 size_t max = TYPE_LENGTH (type);
2495 struct gdbarch *objfile_gdbarch = get_objfile_arch (objfile);
2496 struct cleanup *cleanup;
2498 if (subobj_byte_offset + len > max)
2499 invalid_synthetic_pointer ();
2501 /* Preserve VALUE because we are going to free values back
2502 to the mark, but we still need the value contents
2504 value_incref (value);
2505 free_values.free_to_mark ();
2506 cleanup = make_cleanup_value_free (value);
2508 retval = allocate_value (subobj_type);
2510 /* The given offset is relative to the actual object. */
2511 if (gdbarch_byte_order (objfile_gdbarch) == BFD_ENDIAN_BIG)
2512 subobj_byte_offset += n - max;
2514 memcpy (value_contents_raw (retval),
2515 value_contents_all (value) + subobj_byte_offset, len);
2517 do_cleanups (cleanup);
2521 case DWARF_VALUE_LITERAL:
2524 size_t n = TYPE_LENGTH (subobj_type);
2526 if (subobj_byte_offset + n > ctx.len)
2527 invalid_synthetic_pointer ();
2529 free_values.free_to_mark ();
2530 retval = allocate_value (subobj_type);
2531 contents = value_contents_raw (retval);
2532 memcpy (contents, ctx.data + subobj_byte_offset, n);
2536 case DWARF_VALUE_OPTIMIZED_OUT:
2537 free_values.free_to_mark ();
2538 retval = allocate_optimized_out_value (subobj_type);
2541 /* DWARF_VALUE_IMPLICIT_POINTER was converted to a pieced
2542 operation by execute_stack_op. */
2543 case DWARF_VALUE_IMPLICIT_POINTER:
2544 /* DWARF_VALUE_OPTIMIZED_OUT can't occur in this context --
2545 it can only be encountered when making a piece. */
2547 internal_error (__FILE__, __LINE__, _("invalid location type"));
2551 set_value_initialized (retval, ctx.initialized);
2556 /* The exported interface to dwarf2_evaluate_loc_desc_full; it always
2557 passes 0 as the byte_offset. */
2560 dwarf2_evaluate_loc_desc (struct type *type, struct frame_info *frame,
2561 const gdb_byte *data, size_t size,
2562 struct dwarf2_per_cu_data *per_cu)
2564 return dwarf2_evaluate_loc_desc_full (type, frame, data, size, per_cu,
2568 /* Evaluates a dwarf expression and stores the result in VAL, expecting
2569 that the dwarf expression only produces a single CORE_ADDR. FRAME is the
2570 frame in which the expression is evaluated. ADDR is a context (location of
2571 a variable) and might be needed to evaluate the location expression.
2572 Returns 1 on success, 0 otherwise. */
2575 dwarf2_locexpr_baton_eval (const struct dwarf2_locexpr_baton *dlbaton,
2576 struct frame_info *frame,
2580 struct objfile *objfile;
2582 if (dlbaton == NULL || dlbaton->size == 0)
2585 dwarf_evaluate_loc_desc ctx;
2588 ctx.per_cu = dlbaton->per_cu;
2589 ctx.obj_address = addr;
2591 objfile = dwarf2_per_cu_objfile (dlbaton->per_cu);
2593 ctx.gdbarch = get_objfile_arch (objfile);
2594 ctx.addr_size = dwarf2_per_cu_addr_size (dlbaton->per_cu);
2595 ctx.ref_addr_size = dwarf2_per_cu_ref_addr_size (dlbaton->per_cu);
2596 ctx.offset = dwarf2_per_cu_text_offset (dlbaton->per_cu);
2598 ctx.eval (dlbaton->data, dlbaton->size);
2600 switch (ctx.location)
2602 case DWARF_VALUE_REGISTER:
2603 case DWARF_VALUE_MEMORY:
2604 case DWARF_VALUE_STACK:
2605 *valp = ctx.fetch_address (0);
2606 if (ctx.location == DWARF_VALUE_REGISTER)
2607 *valp = ctx.read_addr_from_reg (*valp);
2609 case DWARF_VALUE_LITERAL:
2610 *valp = extract_signed_integer (ctx.data, ctx.len,
2611 gdbarch_byte_order (ctx.gdbarch));
2613 /* Unsupported dwarf values. */
2614 case DWARF_VALUE_OPTIMIZED_OUT:
2615 case DWARF_VALUE_IMPLICIT_POINTER:
2622 /* See dwarf2loc.h. */
2625 dwarf2_evaluate_property (const struct dynamic_prop *prop,
2626 struct frame_info *frame,
2627 struct property_addr_info *addr_stack,
2633 if (frame == NULL && has_stack_frames ())
2634 frame = get_selected_frame (NULL);
2640 const struct dwarf2_property_baton *baton
2641 = (const struct dwarf2_property_baton *) prop->data.baton;
2643 if (dwarf2_locexpr_baton_eval (&baton->locexpr, frame,
2644 addr_stack ? addr_stack->addr : 0,
2647 if (baton->referenced_type)
2649 struct value *val = value_at (baton->referenced_type, *value);
2651 *value = value_as_address (val);
2660 struct dwarf2_property_baton *baton
2661 = (struct dwarf2_property_baton *) prop->data.baton;
2662 CORE_ADDR pc = get_frame_address_in_block (frame);
2663 const gdb_byte *data;
2667 data = dwarf2_find_location_expression (&baton->loclist, &size, pc);
2670 val = dwarf2_evaluate_loc_desc (baton->referenced_type, frame, data,
2671 size, baton->loclist.per_cu);
2672 if (!value_optimized_out (val))
2674 *value = value_as_address (val);
2682 *value = prop->data.const_val;
2685 case PROP_ADDR_OFFSET:
2687 struct dwarf2_property_baton *baton
2688 = (struct dwarf2_property_baton *) prop->data.baton;
2689 struct property_addr_info *pinfo;
2692 for (pinfo = addr_stack; pinfo != NULL; pinfo = pinfo->next)
2693 if (pinfo->type == baton->referenced_type)
2696 error (_("cannot find reference address for offset property"));
2697 if (pinfo->valaddr != NULL)
2698 val = value_from_contents
2699 (baton->offset_info.type,
2700 pinfo->valaddr + baton->offset_info.offset);
2702 val = value_at (baton->offset_info.type,
2703 pinfo->addr + baton->offset_info.offset);
2704 *value = value_as_address (val);
2712 /* See dwarf2loc.h. */
2715 dwarf2_compile_property_to_c (string_file &stream,
2716 const char *result_name,
2717 struct gdbarch *gdbarch,
2718 unsigned char *registers_used,
2719 const struct dynamic_prop *prop,
2723 struct dwarf2_property_baton *baton
2724 = (struct dwarf2_property_baton *) prop->data.baton;
2725 const gdb_byte *data;
2727 struct dwarf2_per_cu_data *per_cu;
2729 if (prop->kind == PROP_LOCEXPR)
2731 data = baton->locexpr.data;
2732 size = baton->locexpr.size;
2733 per_cu = baton->locexpr.per_cu;
2737 gdb_assert (prop->kind == PROP_LOCLIST);
2739 data = dwarf2_find_location_expression (&baton->loclist, &size, pc);
2740 per_cu = baton->loclist.per_cu;
2743 compile_dwarf_bounds_to_c (stream, result_name, prop, sym, pc,
2744 gdbarch, registers_used,
2745 dwarf2_per_cu_addr_size (per_cu),
2746 data, data + size, per_cu);
2750 /* Helper functions and baton for dwarf2_loc_desc_get_symbol_read_needs. */
2752 class symbol_needs_eval_context : public dwarf_expr_context
2756 enum symbol_needs_kind needs;
2757 struct dwarf2_per_cu_data *per_cu;
2759 /* Reads from registers do require a frame. */
2760 CORE_ADDR read_addr_from_reg (int regnum) OVERRIDE
2762 needs = SYMBOL_NEEDS_FRAME;
2766 /* "get_reg_value" callback: Reads from registers do require a
2769 struct value *get_reg_value (struct type *type, int regnum) OVERRIDE
2771 needs = SYMBOL_NEEDS_FRAME;
2772 return value_zero (type, not_lval);
2775 /* Reads from memory do not require a frame. */
2776 void read_mem (gdb_byte *buf, CORE_ADDR addr, size_t len) OVERRIDE
2778 memset (buf, 0, len);
2781 /* Frame-relative accesses do require a frame. */
2782 void get_frame_base (const gdb_byte **start, size_t *length) OVERRIDE
2784 static gdb_byte lit0 = DW_OP_lit0;
2789 needs = SYMBOL_NEEDS_FRAME;
2792 /* CFA accesses require a frame. */
2793 CORE_ADDR get_frame_cfa () OVERRIDE
2795 needs = SYMBOL_NEEDS_FRAME;
2799 CORE_ADDR get_frame_pc () OVERRIDE
2801 needs = SYMBOL_NEEDS_FRAME;
2805 /* Thread-local accesses require registers, but not a frame. */
2806 CORE_ADDR get_tls_address (CORE_ADDR offset) OVERRIDE
2808 if (needs <= SYMBOL_NEEDS_REGISTERS)
2809 needs = SYMBOL_NEEDS_REGISTERS;
2813 /* Helper interface of per_cu_dwarf_call for
2814 dwarf2_loc_desc_get_symbol_read_needs. */
2816 void dwarf_call (cu_offset die_offset) OVERRIDE
2818 per_cu_dwarf_call (this, die_offset, per_cu);
2821 /* DW_OP_entry_value accesses require a caller, therefore a
2824 void push_dwarf_reg_entry_value (enum call_site_parameter_kind kind,
2825 union call_site_parameter_u kind_u,
2826 int deref_size) OVERRIDE
2828 needs = SYMBOL_NEEDS_FRAME;
2830 /* The expression may require some stub values on DWARF stack. */
2831 push_address (0, 0);
2834 /* DW_OP_GNU_addr_index doesn't require a frame. */
2836 CORE_ADDR get_addr_index (unsigned int index) OVERRIDE
2838 /* Nothing to do. */
2842 /* DW_OP_push_object_address has a frame already passed through. */
2844 CORE_ADDR get_object_address () OVERRIDE
2846 /* Nothing to do. */
2851 /* Compute the correct symbol_needs_kind value for the location
2852 expression at DATA (length SIZE). */
2854 static enum symbol_needs_kind
2855 dwarf2_loc_desc_get_symbol_read_needs (const gdb_byte *data, size_t size,
2856 struct dwarf2_per_cu_data *per_cu)
2859 struct objfile *objfile = dwarf2_per_cu_objfile (per_cu);
2861 scoped_value_mark free_values;
2863 symbol_needs_eval_context ctx;
2865 ctx.needs = SYMBOL_NEEDS_NONE;
2866 ctx.per_cu = per_cu;
2867 ctx.gdbarch = get_objfile_arch (objfile);
2868 ctx.addr_size = dwarf2_per_cu_addr_size (per_cu);
2869 ctx.ref_addr_size = dwarf2_per_cu_ref_addr_size (per_cu);
2870 ctx.offset = dwarf2_per_cu_text_offset (per_cu);
2872 ctx.eval (data, size);
2874 in_reg = ctx.location == DWARF_VALUE_REGISTER;
2876 if (ctx.num_pieces > 0)
2880 /* If the location has several pieces, and any of them are in
2881 registers, then we will need a frame to fetch them from. */
2882 for (i = 0; i < ctx.num_pieces; i++)
2883 if (ctx.pieces[i].location == DWARF_VALUE_REGISTER)
2888 ctx.needs = SYMBOL_NEEDS_FRAME;
2892 /* A helper function that throws an unimplemented error mentioning a
2893 given DWARF operator. */
2896 unimplemented (unsigned int op)
2898 const char *name = get_DW_OP_name (op);
2901 error (_("DWARF operator %s cannot be translated to an agent expression"),
2904 error (_("Unknown DWARF operator 0x%02x cannot be translated "
2905 "to an agent expression"),
2911 This is basically a wrapper on gdbarch_dwarf2_reg_to_regnum so that we
2912 can issue a complaint, which is better than having every target's
2913 implementation of dwarf2_reg_to_regnum do it. */
2916 dwarf_reg_to_regnum (struct gdbarch *arch, int dwarf_reg)
2918 int reg = gdbarch_dwarf2_reg_to_regnum (arch, dwarf_reg);
2922 complaint (&symfile_complaints,
2923 _("bad DWARF register number %d"), dwarf_reg);
2928 /* Subroutine of dwarf_reg_to_regnum_or_error to simplify it.
2929 Throw an error because DWARF_REG is bad. */
2932 throw_bad_regnum_error (ULONGEST dwarf_reg)
2934 /* Still want to print -1 as "-1".
2935 We *could* have int and ULONGEST versions of dwarf2_reg_to_regnum_or_error
2936 but that's overkill for now. */
2937 if ((int) dwarf_reg == dwarf_reg)
2938 error (_("Unable to access DWARF register number %d"), (int) dwarf_reg);
2939 error (_("Unable to access DWARF register number %s"),
2940 pulongest (dwarf_reg));
2943 /* See dwarf2loc.h. */
2946 dwarf_reg_to_regnum_or_error (struct gdbarch *arch, ULONGEST dwarf_reg)
2950 if (dwarf_reg > INT_MAX)
2951 throw_bad_regnum_error (dwarf_reg);
2952 /* Yes, we will end up issuing a complaint and an error if DWARF_REG is
2953 bad, but that's ok. */
2954 reg = dwarf_reg_to_regnum (arch, (int) dwarf_reg);
2956 throw_bad_regnum_error (dwarf_reg);
2960 /* A helper function that emits an access to memory. ARCH is the
2961 target architecture. EXPR is the expression which we are building.
2962 NBITS is the number of bits we want to read. This emits the
2963 opcodes needed to read the memory and then extract the desired
2967 access_memory (struct gdbarch *arch, struct agent_expr *expr, ULONGEST nbits)
2969 ULONGEST nbytes = (nbits + 7) / 8;
2971 gdb_assert (nbytes > 0 && nbytes <= sizeof (LONGEST));
2974 ax_trace_quick (expr, nbytes);
2977 ax_simple (expr, aop_ref8);
2978 else if (nbits <= 16)
2979 ax_simple (expr, aop_ref16);
2980 else if (nbits <= 32)
2981 ax_simple (expr, aop_ref32);
2983 ax_simple (expr, aop_ref64);
2985 /* If we read exactly the number of bytes we wanted, we're done. */
2986 if (8 * nbytes == nbits)
2989 if (gdbarch_bits_big_endian (arch))
2991 /* On a bits-big-endian machine, we want the high-order
2993 ax_const_l (expr, 8 * nbytes - nbits);
2994 ax_simple (expr, aop_rsh_unsigned);
2998 /* On a bits-little-endian box, we want the low-order NBITS. */
2999 ax_zero_ext (expr, nbits);
3003 /* A helper function to return the frame's PC. */
3006 get_ax_pc (void *baton)
3008 struct agent_expr *expr = (struct agent_expr *) baton;
3013 /* Compile a DWARF location expression to an agent expression.
3015 EXPR is the agent expression we are building.
3016 LOC is the agent value we modify.
3017 ARCH is the architecture.
3018 ADDR_SIZE is the size of addresses, in bytes.
3019 OP_PTR is the start of the location expression.
3020 OP_END is one past the last byte of the location expression.
3022 This will throw an exception for various kinds of errors -- for
3023 example, if the expression cannot be compiled, or if the expression
3027 dwarf2_compile_expr_to_ax (struct agent_expr *expr, struct axs_value *loc,
3028 struct gdbarch *arch, unsigned int addr_size,
3029 const gdb_byte *op_ptr, const gdb_byte *op_end,
3030 struct dwarf2_per_cu_data *per_cu)
3033 std::vector<int> dw_labels, patches;
3034 const gdb_byte * const base = op_ptr;
3035 const gdb_byte *previous_piece = op_ptr;
3036 enum bfd_endian byte_order = gdbarch_byte_order (arch);
3037 ULONGEST bits_collected = 0;
3038 unsigned int addr_size_bits = 8 * addr_size;
3039 int bits_big_endian = gdbarch_bits_big_endian (arch);
3041 std::vector<int> offsets (op_end - op_ptr, -1);
3043 /* By default we are making an address. */
3044 loc->kind = axs_lvalue_memory;
3046 while (op_ptr < op_end)
3048 enum dwarf_location_atom op = (enum dwarf_location_atom) *op_ptr;
3049 uint64_t uoffset, reg;
3053 offsets[op_ptr - base] = expr->len;
3056 /* Our basic approach to code generation is to map DWARF
3057 operations directly to AX operations. However, there are
3060 First, DWARF works on address-sized units, but AX always uses
3061 LONGEST. For most operations we simply ignore this
3062 difference; instead we generate sign extensions as needed
3063 before division and comparison operations. It would be nice
3064 to omit the sign extensions, but there is no way to determine
3065 the size of the target's LONGEST. (This code uses the size
3066 of the host LONGEST in some cases -- that is a bug but it is
3069 Second, some DWARF operations cannot be translated to AX.
3070 For these we simply fail. See
3071 http://sourceware.org/bugzilla/show_bug.cgi?id=11662. */
3106 ax_const_l (expr, op - DW_OP_lit0);
3110 uoffset = extract_unsigned_integer (op_ptr, addr_size, byte_order);
3111 op_ptr += addr_size;
3112 /* Some versions of GCC emit DW_OP_addr before
3113 DW_OP_GNU_push_tls_address. In this case the value is an
3114 index, not an address. We don't support things like
3115 branching between the address and the TLS op. */
3116 if (op_ptr >= op_end || *op_ptr != DW_OP_GNU_push_tls_address)
3117 uoffset += dwarf2_per_cu_text_offset (per_cu);
3118 ax_const_l (expr, uoffset);
3122 ax_const_l (expr, extract_unsigned_integer (op_ptr, 1, byte_order));
3126 ax_const_l (expr, extract_signed_integer (op_ptr, 1, byte_order));
3130 ax_const_l (expr, extract_unsigned_integer (op_ptr, 2, byte_order));
3134 ax_const_l (expr, extract_signed_integer (op_ptr, 2, byte_order));
3138 ax_const_l (expr, extract_unsigned_integer (op_ptr, 4, byte_order));
3142 ax_const_l (expr, extract_signed_integer (op_ptr, 4, byte_order));
3146 ax_const_l (expr, extract_unsigned_integer (op_ptr, 8, byte_order));
3150 ax_const_l (expr, extract_signed_integer (op_ptr, 8, byte_order));
3154 op_ptr = safe_read_uleb128 (op_ptr, op_end, &uoffset);
3155 ax_const_l (expr, uoffset);
3158 op_ptr = safe_read_sleb128 (op_ptr, op_end, &offset);
3159 ax_const_l (expr, offset);
3194 dwarf_expr_require_composition (op_ptr, op_end, "DW_OP_regx");
3195 loc->u.reg = dwarf_reg_to_regnum_or_error (arch, op - DW_OP_reg0);
3196 loc->kind = axs_lvalue_register;
3200 op_ptr = safe_read_uleb128 (op_ptr, op_end, ®);
3201 dwarf_expr_require_composition (op_ptr, op_end, "DW_OP_regx");
3202 loc->u.reg = dwarf_reg_to_regnum_or_error (arch, reg);
3203 loc->kind = axs_lvalue_register;
3206 case DW_OP_implicit_value:
3210 op_ptr = safe_read_uleb128 (op_ptr, op_end, &len);
3211 if (op_ptr + len > op_end)
3212 error (_("DW_OP_implicit_value: too few bytes available."));
3213 if (len > sizeof (ULONGEST))
3214 error (_("Cannot translate DW_OP_implicit_value of %d bytes"),
3217 ax_const_l (expr, extract_unsigned_integer (op_ptr, len,
3220 dwarf_expr_require_composition (op_ptr, op_end,
3221 "DW_OP_implicit_value");
3223 loc->kind = axs_rvalue;
3227 case DW_OP_stack_value:
3228 dwarf_expr_require_composition (op_ptr, op_end, "DW_OP_stack_value");
3229 loc->kind = axs_rvalue;
3264 op_ptr = safe_read_sleb128 (op_ptr, op_end, &offset);
3265 i = dwarf_reg_to_regnum_or_error (arch, op - DW_OP_breg0);
3269 ax_const_l (expr, offset);
3270 ax_simple (expr, aop_add);
3275 op_ptr = safe_read_uleb128 (op_ptr, op_end, ®);
3276 op_ptr = safe_read_sleb128 (op_ptr, op_end, &offset);
3277 i = dwarf_reg_to_regnum_or_error (arch, reg);
3281 ax_const_l (expr, offset);
3282 ax_simple (expr, aop_add);
3288 const gdb_byte *datastart;
3290 const struct block *b;
3291 struct symbol *framefunc;
3293 b = block_for_pc (expr->scope);
3296 error (_("No block found for address"));
3298 framefunc = block_linkage_function (b);
3301 error (_("No function found for block"));
3303 func_get_frame_base_dwarf_block (framefunc, expr->scope,
3304 &datastart, &datalen);
3306 op_ptr = safe_read_sleb128 (op_ptr, op_end, &offset);
3307 dwarf2_compile_expr_to_ax (expr, loc, arch, addr_size, datastart,
3308 datastart + datalen, per_cu);
3309 if (loc->kind == axs_lvalue_register)
3310 require_rvalue (expr, loc);
3314 ax_const_l (expr, offset);
3315 ax_simple (expr, aop_add);
3318 loc->kind = axs_lvalue_memory;
3323 ax_simple (expr, aop_dup);
3327 ax_simple (expr, aop_pop);
3332 ax_pick (expr, offset);
3336 ax_simple (expr, aop_swap);
3344 ax_simple (expr, aop_rot);
3348 case DW_OP_deref_size:
3352 if (op == DW_OP_deref_size)
3357 if (size != 1 && size != 2 && size != 4 && size != 8)
3358 error (_("Unsupported size %d in %s"),
3359 size, get_DW_OP_name (op));
3360 access_memory (arch, expr, size * TARGET_CHAR_BIT);
3365 /* Sign extend the operand. */
3366 ax_ext (expr, addr_size_bits);
3367 ax_simple (expr, aop_dup);
3368 ax_const_l (expr, 0);
3369 ax_simple (expr, aop_less_signed);
3370 ax_simple (expr, aop_log_not);
3371 i = ax_goto (expr, aop_if_goto);
3372 /* We have to emit 0 - X. */
3373 ax_const_l (expr, 0);
3374 ax_simple (expr, aop_swap);
3375 ax_simple (expr, aop_sub);
3376 ax_label (expr, i, expr->len);
3380 /* No need to sign extend here. */
3381 ax_const_l (expr, 0);
3382 ax_simple (expr, aop_swap);
3383 ax_simple (expr, aop_sub);
3387 /* Sign extend the operand. */
3388 ax_ext (expr, addr_size_bits);
3389 ax_simple (expr, aop_bit_not);
3392 case DW_OP_plus_uconst:
3393 op_ptr = safe_read_uleb128 (op_ptr, op_end, ®);
3394 /* It would be really weird to emit `DW_OP_plus_uconst 0',
3395 but we micro-optimize anyhow. */
3398 ax_const_l (expr, reg);
3399 ax_simple (expr, aop_add);
3404 ax_simple (expr, aop_bit_and);
3408 /* Sign extend the operands. */
3409 ax_ext (expr, addr_size_bits);
3410 ax_simple (expr, aop_swap);
3411 ax_ext (expr, addr_size_bits);
3412 ax_simple (expr, aop_swap);
3413 ax_simple (expr, aop_div_signed);
3417 ax_simple (expr, aop_sub);
3421 ax_simple (expr, aop_rem_unsigned);
3425 ax_simple (expr, aop_mul);
3429 ax_simple (expr, aop_bit_or);
3433 ax_simple (expr, aop_add);
3437 ax_simple (expr, aop_lsh);
3441 ax_simple (expr, aop_rsh_unsigned);
3445 ax_simple (expr, aop_rsh_signed);
3449 ax_simple (expr, aop_bit_xor);
3453 /* Sign extend the operands. */
3454 ax_ext (expr, addr_size_bits);
3455 ax_simple (expr, aop_swap);
3456 ax_ext (expr, addr_size_bits);
3457 /* Note no swap here: A <= B is !(B < A). */
3458 ax_simple (expr, aop_less_signed);
3459 ax_simple (expr, aop_log_not);
3463 /* Sign extend the operands. */
3464 ax_ext (expr, addr_size_bits);
3465 ax_simple (expr, aop_swap);
3466 ax_ext (expr, addr_size_bits);
3467 ax_simple (expr, aop_swap);
3468 /* A >= B is !(A < B). */
3469 ax_simple (expr, aop_less_signed);
3470 ax_simple (expr, aop_log_not);
3474 /* Sign extend the operands. */
3475 ax_ext (expr, addr_size_bits);
3476 ax_simple (expr, aop_swap);
3477 ax_ext (expr, addr_size_bits);
3478 /* No need for a second swap here. */
3479 ax_simple (expr, aop_equal);
3483 /* Sign extend the operands. */
3484 ax_ext (expr, addr_size_bits);
3485 ax_simple (expr, aop_swap);
3486 ax_ext (expr, addr_size_bits);
3487 ax_simple (expr, aop_swap);
3488 ax_simple (expr, aop_less_signed);
3492 /* Sign extend the operands. */
3493 ax_ext (expr, addr_size_bits);
3494 ax_simple (expr, aop_swap);
3495 ax_ext (expr, addr_size_bits);
3496 /* Note no swap here: A > B is B < A. */
3497 ax_simple (expr, aop_less_signed);
3501 /* Sign extend the operands. */
3502 ax_ext (expr, addr_size_bits);
3503 ax_simple (expr, aop_swap);
3504 ax_ext (expr, addr_size_bits);
3505 /* No need for a swap here. */
3506 ax_simple (expr, aop_equal);
3507 ax_simple (expr, aop_log_not);
3510 case DW_OP_call_frame_cfa:
3513 CORE_ADDR text_offset;
3515 const gdb_byte *cfa_start, *cfa_end;
3517 if (dwarf2_fetch_cfa_info (arch, expr->scope, per_cu,
3519 &text_offset, &cfa_start, &cfa_end))
3522 ax_reg (expr, regnum);
3525 ax_const_l (expr, off);
3526 ax_simple (expr, aop_add);
3531 /* Another expression. */
3532 ax_const_l (expr, text_offset);
3533 dwarf2_compile_expr_to_ax (expr, loc, arch, addr_size,
3534 cfa_start, cfa_end, per_cu);
3537 loc->kind = axs_lvalue_memory;
3541 case DW_OP_GNU_push_tls_address:
3542 case DW_OP_form_tls_address:
3546 case DW_OP_push_object_address:
3551 offset = extract_signed_integer (op_ptr, 2, byte_order);
3553 i = ax_goto (expr, aop_goto);
3554 dw_labels.push_back (op_ptr + offset - base);
3555 patches.push_back (i);
3559 offset = extract_signed_integer (op_ptr, 2, byte_order);
3561 /* Zero extend the operand. */
3562 ax_zero_ext (expr, addr_size_bits);
3563 i = ax_goto (expr, aop_if_goto);
3564 dw_labels.push_back (op_ptr + offset - base);
3565 patches.push_back (i);
3572 case DW_OP_bit_piece:
3574 uint64_t size, offset;
3576 if (op_ptr - 1 == previous_piece)
3577 error (_("Cannot translate empty pieces to agent expressions"));
3578 previous_piece = op_ptr - 1;
3580 op_ptr = safe_read_uleb128 (op_ptr, op_end, &size);
3581 if (op == DW_OP_piece)
3587 op_ptr = safe_read_uleb128 (op_ptr, op_end, &offset);
3589 if (bits_collected + size > 8 * sizeof (LONGEST))
3590 error (_("Expression pieces exceed word size"));
3592 /* Access the bits. */
3595 case axs_lvalue_register:
3596 ax_reg (expr, loc->u.reg);
3599 case axs_lvalue_memory:
3600 /* Offset the pointer, if needed. */
3603 ax_const_l (expr, offset / 8);
3604 ax_simple (expr, aop_add);
3607 access_memory (arch, expr, size);
3611 /* For a bits-big-endian target, shift up what we already
3612 have. For a bits-little-endian target, shift up the
3613 new data. Note that there is a potential bug here if
3614 the DWARF expression leaves multiple values on the
3616 if (bits_collected > 0)
3618 if (bits_big_endian)
3620 ax_simple (expr, aop_swap);
3621 ax_const_l (expr, size);
3622 ax_simple (expr, aop_lsh);
3623 /* We don't need a second swap here, because
3624 aop_bit_or is symmetric. */
3628 ax_const_l (expr, size);
3629 ax_simple (expr, aop_lsh);
3631 ax_simple (expr, aop_bit_or);
3634 bits_collected += size;
3635 loc->kind = axs_rvalue;
3639 case DW_OP_GNU_uninit:
3645 struct dwarf2_locexpr_baton block;
3646 int size = (op == DW_OP_call2 ? 2 : 4);
3648 uoffset = extract_unsigned_integer (op_ptr, size, byte_order);
3651 cu_offset offset = (cu_offset) uoffset;
3652 block = dwarf2_fetch_die_loc_cu_off (offset, per_cu,
3655 /* DW_OP_call_ref is currently not supported. */
3656 gdb_assert (block.per_cu == per_cu);
3658 dwarf2_compile_expr_to_ax (expr, loc, arch, addr_size,
3659 block.data, block.data + block.size,
3664 case DW_OP_call_ref:
3672 /* Patch all the branches we emitted. */
3673 for (i = 0; i < patches.size (); ++i)
3675 int targ = offsets[dw_labels[i]];
3677 internal_error (__FILE__, __LINE__, _("invalid label"));
3678 ax_label (expr, patches[i], targ);
3683 /* Return the value of SYMBOL in FRAME using the DWARF-2 expression
3684 evaluator to calculate the location. */
3685 static struct value *
3686 locexpr_read_variable (struct symbol *symbol, struct frame_info *frame)
3688 struct dwarf2_locexpr_baton *dlbaton
3689 = (struct dwarf2_locexpr_baton *) SYMBOL_LOCATION_BATON (symbol);
3692 val = dwarf2_evaluate_loc_desc (SYMBOL_TYPE (symbol), frame, dlbaton->data,
3693 dlbaton->size, dlbaton->per_cu);
3698 /* Return the value of SYMBOL in FRAME at (callee) FRAME's function
3699 entry. SYMBOL should be a function parameter, otherwise NO_ENTRY_VALUE_ERROR
3702 static struct value *
3703 locexpr_read_variable_at_entry (struct symbol *symbol, struct frame_info *frame)
3705 struct dwarf2_locexpr_baton *dlbaton
3706 = (struct dwarf2_locexpr_baton *) SYMBOL_LOCATION_BATON (symbol);
3708 return value_of_dwarf_block_entry (SYMBOL_TYPE (symbol), frame, dlbaton->data,
3712 /* Implementation of get_symbol_read_needs from
3713 symbol_computed_ops. */
3715 static enum symbol_needs_kind
3716 locexpr_get_symbol_read_needs (struct symbol *symbol)
3718 struct dwarf2_locexpr_baton *dlbaton
3719 = (struct dwarf2_locexpr_baton *) SYMBOL_LOCATION_BATON (symbol);
3721 return dwarf2_loc_desc_get_symbol_read_needs (dlbaton->data, dlbaton->size,
3725 /* Return true if DATA points to the end of a piece. END is one past
3726 the last byte in the expression. */
3729 piece_end_p (const gdb_byte *data, const gdb_byte *end)
3731 return data == end || data[0] == DW_OP_piece || data[0] == DW_OP_bit_piece;
3734 /* Helper for locexpr_describe_location_piece that finds the name of a
3738 locexpr_regname (struct gdbarch *gdbarch, int dwarf_regnum)
3742 /* This doesn't use dwarf_reg_to_regnum_or_error on purpose.
3743 We'd rather print *something* here than throw an error. */
3744 regnum = dwarf_reg_to_regnum (gdbarch, dwarf_regnum);
3745 /* gdbarch_register_name may just return "", return something more
3746 descriptive for bad register numbers. */
3749 /* The text is output as "$bad_register_number".
3750 That is why we use the underscores. */
3751 return _("bad_register_number");
3753 return gdbarch_register_name (gdbarch, regnum);
3756 /* Nicely describe a single piece of a location, returning an updated
3757 position in the bytecode sequence. This function cannot recognize
3758 all locations; if a location is not recognized, it simply returns
3759 DATA. If there is an error during reading, e.g. we run off the end
3760 of the buffer, an error is thrown. */
3762 static const gdb_byte *
3763 locexpr_describe_location_piece (struct symbol *symbol, struct ui_file *stream,
3764 CORE_ADDR addr, struct objfile *objfile,
3765 struct dwarf2_per_cu_data *per_cu,
3766 const gdb_byte *data, const gdb_byte *end,
3767 unsigned int addr_size)
3769 struct gdbarch *gdbarch = get_objfile_arch (objfile);
3772 if (data[0] >= DW_OP_reg0 && data[0] <= DW_OP_reg31)
3774 fprintf_filtered (stream, _("a variable in $%s"),
3775 locexpr_regname (gdbarch, data[0] - DW_OP_reg0));
3778 else if (data[0] == DW_OP_regx)
3782 data = safe_read_uleb128 (data + 1, end, ®);
3783 fprintf_filtered (stream, _("a variable in $%s"),
3784 locexpr_regname (gdbarch, reg));
3786 else if (data[0] == DW_OP_fbreg)
3788 const struct block *b;
3789 struct symbol *framefunc;
3791 int64_t frame_offset;
3792 const gdb_byte *base_data, *new_data, *save_data = data;
3794 int64_t base_offset = 0;
3796 new_data = safe_read_sleb128 (data + 1, end, &frame_offset);
3797 if (!piece_end_p (new_data, end))
3801 b = block_for_pc (addr);
3804 error (_("No block found for address for symbol \"%s\"."),
3805 SYMBOL_PRINT_NAME (symbol));
3807 framefunc = block_linkage_function (b);
3810 error (_("No function found for block for symbol \"%s\"."),
3811 SYMBOL_PRINT_NAME (symbol));
3813 func_get_frame_base_dwarf_block (framefunc, addr, &base_data, &base_size);
3815 if (base_data[0] >= DW_OP_breg0 && base_data[0] <= DW_OP_breg31)
3817 const gdb_byte *buf_end;
3819 frame_reg = base_data[0] - DW_OP_breg0;
3820 buf_end = safe_read_sleb128 (base_data + 1, base_data + base_size,
3822 if (buf_end != base_data + base_size)
3823 error (_("Unexpected opcode after "
3824 "DW_OP_breg%u for symbol \"%s\"."),
3825 frame_reg, SYMBOL_PRINT_NAME (symbol));
3827 else if (base_data[0] >= DW_OP_reg0 && base_data[0] <= DW_OP_reg31)
3829 /* The frame base is just the register, with no offset. */
3830 frame_reg = base_data[0] - DW_OP_reg0;
3835 /* We don't know what to do with the frame base expression,
3836 so we can't trace this variable; give up. */
3840 fprintf_filtered (stream,
3841 _("a variable at frame base reg $%s offset %s+%s"),
3842 locexpr_regname (gdbarch, frame_reg),
3843 plongest (base_offset), plongest (frame_offset));
3845 else if (data[0] >= DW_OP_breg0 && data[0] <= DW_OP_breg31
3846 && piece_end_p (data, end))
3850 data = safe_read_sleb128 (data + 1, end, &offset);
3852 fprintf_filtered (stream,
3853 _("a variable at offset %s from base reg $%s"),
3855 locexpr_regname (gdbarch, data[0] - DW_OP_breg0));
3858 /* The location expression for a TLS variable looks like this (on a
3861 DW_AT_location : 10 byte block: 3 4 0 0 0 0 0 0 0 e0
3862 (DW_OP_addr: 4; DW_OP_GNU_push_tls_address)
3864 0x3 is the encoding for DW_OP_addr, which has an operand as long
3865 as the size of an address on the target machine (here is 8
3866 bytes). Note that more recent version of GCC emit DW_OP_const4u
3867 or DW_OP_const8u, depending on address size, rather than
3868 DW_OP_addr. 0xe0 is the encoding for DW_OP_GNU_push_tls_address.
3869 The operand represents the offset at which the variable is within
3870 the thread local storage. */
3872 else if (data + 1 + addr_size < end
3873 && (data[0] == DW_OP_addr
3874 || (addr_size == 4 && data[0] == DW_OP_const4u)
3875 || (addr_size == 8 && data[0] == DW_OP_const8u))
3876 && (data[1 + addr_size] == DW_OP_GNU_push_tls_address
3877 || data[1 + addr_size] == DW_OP_form_tls_address)
3878 && piece_end_p (data + 2 + addr_size, end))
3881 offset = extract_unsigned_integer (data + 1, addr_size,
3882 gdbarch_byte_order (gdbarch));
3884 fprintf_filtered (stream,
3885 _("a thread-local variable at offset 0x%s "
3886 "in the thread-local storage for `%s'"),
3887 phex_nz (offset, addr_size), objfile_name (objfile));
3889 data += 1 + addr_size + 1;
3892 /* With -gsplit-dwarf a TLS variable can also look like this:
3893 DW_AT_location : 3 byte block: fc 4 e0
3894 (DW_OP_GNU_const_index: 4;
3895 DW_OP_GNU_push_tls_address) */
3896 else if (data + 3 <= end
3897 && data + 1 + (leb128_size = skip_leb128 (data + 1, end)) < end
3898 && data[0] == DW_OP_GNU_const_index
3900 && (data[1 + leb128_size] == DW_OP_GNU_push_tls_address
3901 || data[1 + leb128_size] == DW_OP_form_tls_address)
3902 && piece_end_p (data + 2 + leb128_size, end))
3906 data = safe_read_uleb128 (data + 1, end, &offset);
3907 offset = dwarf2_read_addr_index (per_cu, offset);
3908 fprintf_filtered (stream,
3909 _("a thread-local variable at offset 0x%s "
3910 "in the thread-local storage for `%s'"),
3911 phex_nz (offset, addr_size), objfile_name (objfile));
3915 else if (data[0] >= DW_OP_lit0
3916 && data[0] <= DW_OP_lit31
3918 && data[1] == DW_OP_stack_value)
3920 fprintf_filtered (stream, _("the constant %d"), data[0] - DW_OP_lit0);
3927 /* Disassemble an expression, stopping at the end of a piece or at the
3928 end of the expression. Returns a pointer to the next unread byte
3929 in the input expression. If ALL is nonzero, then this function
3930 will keep going until it reaches the end of the expression.
3931 If there is an error during reading, e.g. we run off the end
3932 of the buffer, an error is thrown. */
3934 static const gdb_byte *
3935 disassemble_dwarf_expression (struct ui_file *stream,
3936 struct gdbarch *arch, unsigned int addr_size,
3937 int offset_size, const gdb_byte *start,
3938 const gdb_byte *data, const gdb_byte *end,
3939 int indent, int all,
3940 struct dwarf2_per_cu_data *per_cu)
3944 || (data[0] != DW_OP_piece && data[0] != DW_OP_bit_piece)))
3946 enum dwarf_location_atom op = (enum dwarf_location_atom) *data++;
3951 name = get_DW_OP_name (op);
3954 error (_("Unrecognized DWARF opcode 0x%02x at %ld"),
3955 op, (long) (data - 1 - start));
3956 fprintf_filtered (stream, " %*ld: %s", indent + 4,
3957 (long) (data - 1 - start), name);
3962 ul = extract_unsigned_integer (data, addr_size,
3963 gdbarch_byte_order (arch));
3965 fprintf_filtered (stream, " 0x%s", phex_nz (ul, addr_size));
3969 ul = extract_unsigned_integer (data, 1, gdbarch_byte_order (arch));
3971 fprintf_filtered (stream, " %s", pulongest (ul));
3974 l = extract_signed_integer (data, 1, gdbarch_byte_order (arch));
3976 fprintf_filtered (stream, " %s", plongest (l));
3979 ul = extract_unsigned_integer (data, 2, gdbarch_byte_order (arch));
3981 fprintf_filtered (stream, " %s", pulongest (ul));
3984 l = extract_signed_integer (data, 2, gdbarch_byte_order (arch));
3986 fprintf_filtered (stream, " %s", plongest (l));
3989 ul = extract_unsigned_integer (data, 4, gdbarch_byte_order (arch));
3991 fprintf_filtered (stream, " %s", pulongest (ul));
3994 l = extract_signed_integer (data, 4, gdbarch_byte_order (arch));
3996 fprintf_filtered (stream, " %s", plongest (l));
3999 ul = extract_unsigned_integer (data, 8, gdbarch_byte_order (arch));
4001 fprintf_filtered (stream, " %s", pulongest (ul));
4004 l = extract_signed_integer (data, 8, gdbarch_byte_order (arch));
4006 fprintf_filtered (stream, " %s", plongest (l));
4009 data = safe_read_uleb128 (data, end, &ul);
4010 fprintf_filtered (stream, " %s", pulongest (ul));
4013 data = safe_read_sleb128 (data, end, &l);
4014 fprintf_filtered (stream, " %s", plongest (l));
4049 fprintf_filtered (stream, " [$%s]",
4050 locexpr_regname (arch, op - DW_OP_reg0));
4054 data = safe_read_uleb128 (data, end, &ul);
4055 fprintf_filtered (stream, " %s [$%s]", pulongest (ul),
4056 locexpr_regname (arch, (int) ul));
4059 case DW_OP_implicit_value:
4060 data = safe_read_uleb128 (data, end, &ul);
4062 fprintf_filtered (stream, " %s", pulongest (ul));
4097 data = safe_read_sleb128 (data, end, &l);
4098 fprintf_filtered (stream, " %s [$%s]", plongest (l),
4099 locexpr_regname (arch, op - DW_OP_breg0));
4103 data = safe_read_uleb128 (data, end, &ul);
4104 data = safe_read_sleb128 (data, end, &l);
4105 fprintf_filtered (stream, " register %s [$%s] offset %s",
4107 locexpr_regname (arch, (int) ul),
4112 data = safe_read_sleb128 (data, end, &l);
4113 fprintf_filtered (stream, " %s", plongest (l));
4116 case DW_OP_xderef_size:
4117 case DW_OP_deref_size:
4119 fprintf_filtered (stream, " %d", *data);
4123 case DW_OP_plus_uconst:
4124 data = safe_read_uleb128 (data, end, &ul);
4125 fprintf_filtered (stream, " %s", pulongest (ul));
4129 l = extract_signed_integer (data, 2, gdbarch_byte_order (arch));
4131 fprintf_filtered (stream, " to %ld",
4132 (long) (data + l - start));
4136 l = extract_signed_integer (data, 2, gdbarch_byte_order (arch));
4138 fprintf_filtered (stream, " %ld",
4139 (long) (data + l - start));
4143 ul = extract_unsigned_integer (data, 2, gdbarch_byte_order (arch));
4145 fprintf_filtered (stream, " offset %s", phex_nz (ul, 2));
4149 ul = extract_unsigned_integer (data, 4, gdbarch_byte_order (arch));
4151 fprintf_filtered (stream, " offset %s", phex_nz (ul, 4));
4154 case DW_OP_call_ref:
4155 ul = extract_unsigned_integer (data, offset_size,
4156 gdbarch_byte_order (arch));
4157 data += offset_size;
4158 fprintf_filtered (stream, " offset %s", phex_nz (ul, offset_size));
4162 data = safe_read_uleb128 (data, end, &ul);
4163 fprintf_filtered (stream, " %s (bytes)", pulongest (ul));
4166 case DW_OP_bit_piece:
4170 data = safe_read_uleb128 (data, end, &ul);
4171 data = safe_read_uleb128 (data, end, &offset);
4172 fprintf_filtered (stream, " size %s offset %s (bits)",
4173 pulongest (ul), pulongest (offset));
4177 case DW_OP_implicit_pointer:
4178 case DW_OP_GNU_implicit_pointer:
4180 ul = extract_unsigned_integer (data, offset_size,
4181 gdbarch_byte_order (arch));
4182 data += offset_size;
4184 data = safe_read_sleb128 (data, end, &l);
4186 fprintf_filtered (stream, " DIE %s offset %s",
4187 phex_nz (ul, offset_size),
4192 case DW_OP_deref_type:
4193 case DW_OP_GNU_deref_type:
4195 int addr_size = *data++;
4198 data = safe_read_uleb128 (data, end, &ul);
4199 cu_offset offset = (cu_offset) ul;
4200 type = dwarf2_get_die_type (offset, per_cu);
4201 fprintf_filtered (stream, "<");
4202 type_print (type, "", stream, -1);
4203 fprintf_filtered (stream, " [0x%s]> %d",
4204 phex_nz (to_underlying (offset), 0),
4209 case DW_OP_const_type:
4210 case DW_OP_GNU_const_type:
4214 data = safe_read_uleb128 (data, end, &ul);
4215 cu_offset type_die = (cu_offset) ul;
4216 type = dwarf2_get_die_type (type_die, per_cu);
4217 fprintf_filtered (stream, "<");
4218 type_print (type, "", stream, -1);
4219 fprintf_filtered (stream, " [0x%s]>",
4220 phex_nz (to_underlying (type_die), 0));
4224 case DW_OP_regval_type:
4225 case DW_OP_GNU_regval_type:
4230 data = safe_read_uleb128 (data, end, ®);
4231 data = safe_read_uleb128 (data, end, &ul);
4232 cu_offset type_die = (cu_offset) ul;
4234 type = dwarf2_get_die_type (type_die, per_cu);
4235 fprintf_filtered (stream, "<");
4236 type_print (type, "", stream, -1);
4237 fprintf_filtered (stream, " [0x%s]> [$%s]",
4238 phex_nz (to_underlying (type_die), 0),
4239 locexpr_regname (arch, reg));
4244 case DW_OP_GNU_convert:
4245 case DW_OP_reinterpret:
4246 case DW_OP_GNU_reinterpret:
4248 data = safe_read_uleb128 (data, end, &ul);
4249 cu_offset type_die = (cu_offset) ul;
4251 if (to_underlying (type_die) == 0)
4252 fprintf_filtered (stream, "<0>");
4257 type = dwarf2_get_die_type (type_die, per_cu);
4258 fprintf_filtered (stream, "<");
4259 type_print (type, "", stream, -1);
4260 fprintf_filtered (stream, " [0x%s]>",
4261 phex_nz (to_underlying (type_die), 0));
4266 case DW_OP_entry_value:
4267 case DW_OP_GNU_entry_value:
4268 data = safe_read_uleb128 (data, end, &ul);
4269 fputc_filtered ('\n', stream);
4270 disassemble_dwarf_expression (stream, arch, addr_size, offset_size,
4271 start, data, data + ul, indent + 2,
4276 case DW_OP_GNU_parameter_ref:
4277 ul = extract_unsigned_integer (data, 4, gdbarch_byte_order (arch));
4279 fprintf_filtered (stream, " offset %s", phex_nz (ul, 4));
4282 case DW_OP_GNU_addr_index:
4283 data = safe_read_uleb128 (data, end, &ul);
4284 ul = dwarf2_read_addr_index (per_cu, ul);
4285 fprintf_filtered (stream, " 0x%s", phex_nz (ul, addr_size));
4287 case DW_OP_GNU_const_index:
4288 data = safe_read_uleb128 (data, end, &ul);
4289 ul = dwarf2_read_addr_index (per_cu, ul);
4290 fprintf_filtered (stream, " %s", pulongest (ul));
4294 fprintf_filtered (stream, "\n");
4300 /* Describe a single location, which may in turn consist of multiple
4304 locexpr_describe_location_1 (struct symbol *symbol, CORE_ADDR addr,
4305 struct ui_file *stream,
4306 const gdb_byte *data, size_t size,
4307 struct objfile *objfile, unsigned int addr_size,
4308 int offset_size, struct dwarf2_per_cu_data *per_cu)
4310 const gdb_byte *end = data + size;
4311 int first_piece = 1, bad = 0;
4315 const gdb_byte *here = data;
4316 int disassemble = 1;
4321 fprintf_filtered (stream, _(", and "));
4323 if (!dwarf_always_disassemble)
4325 data = locexpr_describe_location_piece (symbol, stream,
4326 addr, objfile, per_cu,
4327 data, end, addr_size);
4328 /* If we printed anything, or if we have an empty piece,
4329 then don't disassemble. */
4331 || data[0] == DW_OP_piece
4332 || data[0] == DW_OP_bit_piece)
4337 fprintf_filtered (stream, _("a complex DWARF expression:\n"));
4338 data = disassemble_dwarf_expression (stream,
4339 get_objfile_arch (objfile),
4340 addr_size, offset_size, data,
4342 dwarf_always_disassemble,
4348 int empty = data == here;
4351 fprintf_filtered (stream, " ");
4352 if (data[0] == DW_OP_piece)
4356 data = safe_read_uleb128 (data + 1, end, &bytes);
4359 fprintf_filtered (stream, _("an empty %s-byte piece"),
4362 fprintf_filtered (stream, _(" [%s-byte piece]"),
4365 else if (data[0] == DW_OP_bit_piece)
4367 uint64_t bits, offset;
4369 data = safe_read_uleb128 (data + 1, end, &bits);
4370 data = safe_read_uleb128 (data, end, &offset);
4373 fprintf_filtered (stream,
4374 _("an empty %s-bit piece"),
4377 fprintf_filtered (stream,
4378 _(" [%s-bit piece, offset %s bits]"),
4379 pulongest (bits), pulongest (offset));
4389 if (bad || data > end)
4390 error (_("Corrupted DWARF2 expression for \"%s\"."),
4391 SYMBOL_PRINT_NAME (symbol));
4394 /* Print a natural-language description of SYMBOL to STREAM. This
4395 version is for a symbol with a single location. */
4398 locexpr_describe_location (struct symbol *symbol, CORE_ADDR addr,
4399 struct ui_file *stream)
4401 struct dwarf2_locexpr_baton *dlbaton
4402 = (struct dwarf2_locexpr_baton *) SYMBOL_LOCATION_BATON (symbol);
4403 struct objfile *objfile = dwarf2_per_cu_objfile (dlbaton->per_cu);
4404 unsigned int addr_size = dwarf2_per_cu_addr_size (dlbaton->per_cu);
4405 int offset_size = dwarf2_per_cu_offset_size (dlbaton->per_cu);
4407 locexpr_describe_location_1 (symbol, addr, stream,
4408 dlbaton->data, dlbaton->size,
4409 objfile, addr_size, offset_size,
4413 /* Describe the location of SYMBOL as an agent value in VALUE, generating
4414 any necessary bytecode in AX. */
4417 locexpr_tracepoint_var_ref (struct symbol *symbol, struct gdbarch *gdbarch,
4418 struct agent_expr *ax, struct axs_value *value)
4420 struct dwarf2_locexpr_baton *dlbaton
4421 = (struct dwarf2_locexpr_baton *) SYMBOL_LOCATION_BATON (symbol);
4422 unsigned int addr_size = dwarf2_per_cu_addr_size (dlbaton->per_cu);
4424 if (dlbaton->size == 0)
4425 value->optimized_out = 1;
4427 dwarf2_compile_expr_to_ax (ax, value, gdbarch, addr_size,
4428 dlbaton->data, dlbaton->data + dlbaton->size,
4432 /* symbol_computed_ops 'generate_c_location' method. */
4435 locexpr_generate_c_location (struct symbol *sym, string_file &stream,
4436 struct gdbarch *gdbarch,
4437 unsigned char *registers_used,
4438 CORE_ADDR pc, const char *result_name)
4440 struct dwarf2_locexpr_baton *dlbaton
4441 = (struct dwarf2_locexpr_baton *) SYMBOL_LOCATION_BATON (sym);
4442 unsigned int addr_size = dwarf2_per_cu_addr_size (dlbaton->per_cu);
4444 if (dlbaton->size == 0)
4445 error (_("symbol \"%s\" is optimized out"), SYMBOL_NATURAL_NAME (sym));
4447 compile_dwarf_expr_to_c (stream, result_name,
4448 sym, pc, gdbarch, registers_used, addr_size,
4449 dlbaton->data, dlbaton->data + dlbaton->size,
4453 /* The set of location functions used with the DWARF-2 expression
4455 const struct symbol_computed_ops dwarf2_locexpr_funcs = {
4456 locexpr_read_variable,
4457 locexpr_read_variable_at_entry,
4458 locexpr_get_symbol_read_needs,
4459 locexpr_describe_location,
4460 0, /* location_has_loclist */
4461 locexpr_tracepoint_var_ref,
4462 locexpr_generate_c_location
4466 /* Wrapper functions for location lists. These generally find
4467 the appropriate location expression and call something above. */
4469 /* Return the value of SYMBOL in FRAME using the DWARF-2 expression
4470 evaluator to calculate the location. */
4471 static struct value *
4472 loclist_read_variable (struct symbol *symbol, struct frame_info *frame)
4474 struct dwarf2_loclist_baton *dlbaton
4475 = (struct dwarf2_loclist_baton *) SYMBOL_LOCATION_BATON (symbol);
4477 const gdb_byte *data;
4479 CORE_ADDR pc = frame ? get_frame_address_in_block (frame) : 0;
4481 data = dwarf2_find_location_expression (dlbaton, &size, pc);
4482 val = dwarf2_evaluate_loc_desc (SYMBOL_TYPE (symbol), frame, data, size,
4488 /* Read variable SYMBOL like loclist_read_variable at (callee) FRAME's function
4489 entry. SYMBOL should be a function parameter, otherwise NO_ENTRY_VALUE_ERROR
4492 Function always returns non-NULL value, it may be marked optimized out if
4493 inferior frame information is not available. It throws NO_ENTRY_VALUE_ERROR
4494 if it cannot resolve the parameter for any reason. */
4496 static struct value *
4497 loclist_read_variable_at_entry (struct symbol *symbol, struct frame_info *frame)
4499 struct dwarf2_loclist_baton *dlbaton
4500 = (struct dwarf2_loclist_baton *) SYMBOL_LOCATION_BATON (symbol);
4501 const gdb_byte *data;
4505 if (frame == NULL || !get_frame_func_if_available (frame, &pc))
4506 return allocate_optimized_out_value (SYMBOL_TYPE (symbol));
4508 data = dwarf2_find_location_expression (dlbaton, &size, pc);
4510 return allocate_optimized_out_value (SYMBOL_TYPE (symbol));
4512 return value_of_dwarf_block_entry (SYMBOL_TYPE (symbol), frame, data, size);
4515 /* Implementation of get_symbol_read_needs from
4516 symbol_computed_ops. */
4518 static enum symbol_needs_kind
4519 loclist_symbol_needs (struct symbol *symbol)
4521 /* If there's a location list, then assume we need to have a frame
4522 to choose the appropriate location expression. With tracking of
4523 global variables this is not necessarily true, but such tracking
4524 is disabled in GCC at the moment until we figure out how to
4527 return SYMBOL_NEEDS_FRAME;
4530 /* Print a natural-language description of SYMBOL to STREAM. This
4531 version applies when there is a list of different locations, each
4532 with a specified address range. */
4535 loclist_describe_location (struct symbol *symbol, CORE_ADDR addr,
4536 struct ui_file *stream)
4538 struct dwarf2_loclist_baton *dlbaton
4539 = (struct dwarf2_loclist_baton *) SYMBOL_LOCATION_BATON (symbol);
4540 const gdb_byte *loc_ptr, *buf_end;
4541 struct objfile *objfile = dwarf2_per_cu_objfile (dlbaton->per_cu);
4542 struct gdbarch *gdbarch = get_objfile_arch (objfile);
4543 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
4544 unsigned int addr_size = dwarf2_per_cu_addr_size (dlbaton->per_cu);
4545 int offset_size = dwarf2_per_cu_offset_size (dlbaton->per_cu);
4546 int signed_addr_p = bfd_get_sign_extend_vma (objfile->obfd);
4547 /* Adjust base_address for relocatable objects. */
4548 CORE_ADDR base_offset = dwarf2_per_cu_text_offset (dlbaton->per_cu);
4549 CORE_ADDR base_address = dlbaton->base_address + base_offset;
4552 loc_ptr = dlbaton->data;
4553 buf_end = dlbaton->data + dlbaton->size;
4555 fprintf_filtered (stream, _("multi-location:\n"));
4557 /* Iterate through locations until we run out. */
4560 CORE_ADDR low = 0, high = 0; /* init for gcc -Wall */
4562 enum debug_loc_kind kind;
4563 const gdb_byte *new_ptr = NULL; /* init for gcc -Wall */
4565 if (dlbaton->from_dwo)
4566 kind = decode_debug_loc_dwo_addresses (dlbaton->per_cu,
4567 loc_ptr, buf_end, &new_ptr,
4568 &low, &high, byte_order);
4570 kind = decode_debug_loc_addresses (loc_ptr, buf_end, &new_ptr,
4572 byte_order, addr_size,
4577 case DEBUG_LOC_END_OF_LIST:
4580 case DEBUG_LOC_BASE_ADDRESS:
4581 base_address = high + base_offset;
4582 fprintf_filtered (stream, _(" Base address %s"),
4583 paddress (gdbarch, base_address));
4585 case DEBUG_LOC_START_END:
4586 case DEBUG_LOC_START_LENGTH:
4588 case DEBUG_LOC_BUFFER_OVERFLOW:
4589 case DEBUG_LOC_INVALID_ENTRY:
4590 error (_("Corrupted DWARF expression for symbol \"%s\"."),
4591 SYMBOL_PRINT_NAME (symbol));
4593 gdb_assert_not_reached ("bad debug_loc_kind");
4596 /* Otherwise, a location expression entry. */
4597 low += base_address;
4598 high += base_address;
4600 low = gdbarch_adjust_dwarf2_addr (gdbarch, low);
4601 high = gdbarch_adjust_dwarf2_addr (gdbarch, high);
4603 length = extract_unsigned_integer (loc_ptr, 2, byte_order);
4606 /* (It would improve readability to print only the minimum
4607 necessary digits of the second number of the range.) */
4608 fprintf_filtered (stream, _(" Range %s-%s: "),
4609 paddress (gdbarch, low), paddress (gdbarch, high));
4611 /* Now describe this particular location. */
4612 locexpr_describe_location_1 (symbol, low, stream, loc_ptr, length,
4613 objfile, addr_size, offset_size,
4616 fprintf_filtered (stream, "\n");
4622 /* Describe the location of SYMBOL as an agent value in VALUE, generating
4623 any necessary bytecode in AX. */
4625 loclist_tracepoint_var_ref (struct symbol *symbol, struct gdbarch *gdbarch,
4626 struct agent_expr *ax, struct axs_value *value)
4628 struct dwarf2_loclist_baton *dlbaton
4629 = (struct dwarf2_loclist_baton *) SYMBOL_LOCATION_BATON (symbol);
4630 const gdb_byte *data;
4632 unsigned int addr_size = dwarf2_per_cu_addr_size (dlbaton->per_cu);
4634 data = dwarf2_find_location_expression (dlbaton, &size, ax->scope);
4636 value->optimized_out = 1;
4638 dwarf2_compile_expr_to_ax (ax, value, gdbarch, addr_size, data, data + size,
4642 /* symbol_computed_ops 'generate_c_location' method. */
4645 loclist_generate_c_location (struct symbol *sym, string_file &stream,
4646 struct gdbarch *gdbarch,
4647 unsigned char *registers_used,
4648 CORE_ADDR pc, const char *result_name)
4650 struct dwarf2_loclist_baton *dlbaton
4651 = (struct dwarf2_loclist_baton *) SYMBOL_LOCATION_BATON (sym);
4652 unsigned int addr_size = dwarf2_per_cu_addr_size (dlbaton->per_cu);
4653 const gdb_byte *data;
4656 data = dwarf2_find_location_expression (dlbaton, &size, pc);
4658 error (_("symbol \"%s\" is optimized out"), SYMBOL_NATURAL_NAME (sym));
4660 compile_dwarf_expr_to_c (stream, result_name,
4661 sym, pc, gdbarch, registers_used, addr_size,
4666 /* The set of location functions used with the DWARF-2 expression
4667 evaluator and location lists. */
4668 const struct symbol_computed_ops dwarf2_loclist_funcs = {
4669 loclist_read_variable,
4670 loclist_read_variable_at_entry,
4671 loclist_symbol_needs,
4672 loclist_describe_location,
4673 1, /* location_has_loclist */
4674 loclist_tracepoint_var_ref,
4675 loclist_generate_c_location
4678 /* Provide a prototype to silence -Wmissing-prototypes. */
4679 extern initialize_file_ftype _initialize_dwarf2loc;
4682 _initialize_dwarf2loc (void)
4684 add_setshow_zuinteger_cmd ("entry-values", class_maintenance,
4685 &entry_values_debug,
4686 _("Set entry values and tail call frames "
4688 _("Show entry values and tail call frames "
4690 _("When non-zero, the process of determining "
4691 "parameter values from function entry point "
4692 "and tail call frames will be printed."),
4694 show_entry_values_debug,
4695 &setdebuglist, &showdebuglist);
4698 register_self_test (selftests::copy_bitwise_tests);