1 /* Find a variable's value in memory, for GDB, the GNU debugger.
3 Copyright (C) 1986-2018 Free Software Foundation, Inc.
5 This file is part of GDB.
7 This program is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3 of the License, or
10 (at your option) any later version.
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with this program. If not, see <http://www.gnu.org/licenses/>. */
28 #include "symfile.h" /* for overlay functions */
30 #include "user-regs.h"
34 #include "dwarf2loc.h"
37 /* Basic byte-swapping routines. All 'extract' functions return a
38 host-format integer from a target-format integer at ADDR which is
41 #if TARGET_CHAR_BIT != 8 || HOST_CHAR_BIT != 8
42 /* 8 bit characters are a pretty safe assumption these days, so we
43 assume it throughout all these swapping routines. If we had to deal with
44 9 bit characters, we would need to make len be in bits and would have
45 to re-write these routines... */
49 template<typename T, typename>
51 extract_integer (const gdb_byte *addr, int len, enum bfd_endian byte_order)
54 const unsigned char *p;
55 const unsigned char *startaddr = addr;
56 const unsigned char *endaddr = startaddr + len;
58 if (len > (int) sizeof (T))
60 That operation is not available on integers of more than %d bytes."),
63 /* Start at the most significant end of the integer, and work towards
64 the least significant. */
65 if (byte_order == BFD_ENDIAN_BIG)
68 if (std::is_signed<T>::value)
70 /* Do the sign extension once at the start. */
71 retval = ((LONGEST) * p ^ 0x80) - 0x80;
74 for (; p < endaddr; ++p)
75 retval = (retval << 8) | *p;
80 if (std::is_signed<T>::value)
82 /* Do the sign extension once at the start. */
83 retval = ((LONGEST) * p ^ 0x80) - 0x80;
86 for (; p >= startaddr; --p)
87 retval = (retval << 8) | *p;
92 /* Explicit instantiations. */
93 template LONGEST extract_integer<LONGEST> (const gdb_byte *addr, int len,
94 enum bfd_endian byte_order);
95 template ULONGEST extract_integer<ULONGEST> (const gdb_byte *addr, int len,
96 enum bfd_endian byte_order);
98 /* Sometimes a long long unsigned integer can be extracted as a
99 LONGEST value. This is done so that we can print these values
100 better. If this integer can be converted to a LONGEST, this
101 function returns 1 and sets *PVAL. Otherwise it returns 0. */
104 extract_long_unsigned_integer (const gdb_byte *addr, int orig_len,
105 enum bfd_endian byte_order, LONGEST *pval)
108 const gdb_byte *first_addr;
112 if (byte_order == BFD_ENDIAN_BIG)
115 len > (int) sizeof (LONGEST) && p < addr + orig_len;
128 for (p = addr + orig_len - 1;
129 len > (int) sizeof (LONGEST) && p >= addr;
139 if (len <= (int) sizeof (LONGEST))
141 *pval = (LONGEST) extract_unsigned_integer (first_addr,
151 /* Treat the bytes at BUF as a pointer of type TYPE, and return the
152 address it represents. */
154 extract_typed_address (const gdb_byte *buf, struct type *type)
156 if (TYPE_CODE (type) != TYPE_CODE_PTR && !TYPE_IS_REFERENCE (type))
157 internal_error (__FILE__, __LINE__,
158 _("extract_typed_address: "
159 "type is not a pointer or reference"));
161 return gdbarch_pointer_to_address (get_type_arch (type), type, buf);
164 /* All 'store' functions accept a host-format integer and store a
165 target-format integer at ADDR which is LEN bytes long. */
166 template<typename T, typename>
168 store_integer (gdb_byte *addr, int len, enum bfd_endian byte_order,
172 gdb_byte *startaddr = addr;
173 gdb_byte *endaddr = startaddr + len;
175 /* Start at the least significant end of the integer, and work towards
176 the most significant. */
177 if (byte_order == BFD_ENDIAN_BIG)
179 for (p = endaddr - 1; p >= startaddr; --p)
187 for (p = startaddr; p < endaddr; ++p)
195 /* Explicit instantiations. */
196 template void store_integer (gdb_byte *addr, int len,
197 enum bfd_endian byte_order,
200 template void store_integer (gdb_byte *addr, int len,
201 enum bfd_endian byte_order,
204 /* Store the address ADDR as a pointer of type TYPE at BUF, in target
207 store_typed_address (gdb_byte *buf, struct type *type, CORE_ADDR addr)
209 if (TYPE_CODE (type) != TYPE_CODE_PTR && !TYPE_IS_REFERENCE (type))
210 internal_error (__FILE__, __LINE__,
211 _("store_typed_address: "
212 "type is not a pointer or reference"));
214 gdbarch_address_to_pointer (get_type_arch (type), type, buf, addr);
217 /* Copy a value from SOURCE of size SOURCE_SIZE bytes to DEST of size DEST_SIZE
218 bytes. If SOURCE_SIZE is greater than DEST_SIZE, then truncate the most
219 significant bytes. If SOURCE_SIZE is less than DEST_SIZE then either sign
220 or zero extended according to IS_SIGNED. Values are stored in memory with
221 endianess BYTE_ORDER. */
224 copy_integer_to_size (gdb_byte *dest, int dest_size, const gdb_byte *source,
225 int source_size, bool is_signed,
226 enum bfd_endian byte_order)
228 signed int size_diff = dest_size - source_size;
230 /* Copy across everything from SOURCE that can fit into DEST. */
232 if (byte_order == BFD_ENDIAN_BIG && size_diff > 0)
233 memcpy (dest + size_diff, source, source_size);
234 else if (byte_order == BFD_ENDIAN_BIG && size_diff < 0)
235 memcpy (dest, source - size_diff, dest_size);
237 memcpy (dest, source, std::min (source_size, dest_size));
239 /* Fill the remaining space in DEST by either zero extending or sign
244 gdb_byte extension = 0;
246 && ((byte_order != BFD_ENDIAN_BIG && source[source_size - 1] & 0x80)
247 || (byte_order == BFD_ENDIAN_BIG && source[0] & 0x80)))
250 /* Extend into MSBs of SOURCE. */
251 if (byte_order == BFD_ENDIAN_BIG)
252 memset (dest, extension, size_diff);
254 memset (dest + source_size, extension, size_diff);
258 /* Return a `value' with the contents of (virtual or cooked) register
259 REGNUM as found in the specified FRAME. The register's type is
260 determined by register_type(). */
263 value_of_register (int regnum, struct frame_info *frame)
265 struct gdbarch *gdbarch = get_frame_arch (frame);
266 struct value *reg_val;
268 /* User registers lie completely outside of the range of normal
269 registers. Catch them early so that the target never sees them. */
270 if (regnum >= gdbarch_num_regs (gdbarch)
271 + gdbarch_num_pseudo_regs (gdbarch))
272 return value_of_user_reg (regnum, frame);
274 reg_val = value_of_register_lazy (frame, regnum);
275 value_fetch_lazy (reg_val);
279 /* Return a `value' with the contents of (virtual or cooked) register
280 REGNUM as found in the specified FRAME. The register's type is
281 determined by register_type(). The value is not fetched. */
284 value_of_register_lazy (struct frame_info *frame, int regnum)
286 struct gdbarch *gdbarch = get_frame_arch (frame);
287 struct value *reg_val;
288 struct frame_info *next_frame;
290 gdb_assert (regnum < (gdbarch_num_regs (gdbarch)
291 + gdbarch_num_pseudo_regs (gdbarch)));
293 gdb_assert (frame != NULL);
295 next_frame = get_next_frame_sentinel_okay (frame);
297 /* We should have a valid next frame. */
298 gdb_assert (frame_id_p (get_frame_id (next_frame)));
300 reg_val = allocate_value_lazy (register_type (gdbarch, regnum));
301 VALUE_LVAL (reg_val) = lval_register;
302 VALUE_REGNUM (reg_val) = regnum;
303 VALUE_NEXT_FRAME_ID (reg_val) = get_frame_id (next_frame);
308 /* Given a pointer of type TYPE in target form in BUF, return the
309 address it represents. */
311 unsigned_pointer_to_address (struct gdbarch *gdbarch,
312 struct type *type, const gdb_byte *buf)
314 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
316 return extract_unsigned_integer (buf, TYPE_LENGTH (type), byte_order);
320 signed_pointer_to_address (struct gdbarch *gdbarch,
321 struct type *type, const gdb_byte *buf)
323 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
325 return extract_signed_integer (buf, TYPE_LENGTH (type), byte_order);
328 /* Given an address, store it as a pointer of type TYPE in target
331 unsigned_address_to_pointer (struct gdbarch *gdbarch, struct type *type,
332 gdb_byte *buf, CORE_ADDR addr)
334 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
336 store_unsigned_integer (buf, TYPE_LENGTH (type), byte_order, addr);
340 address_to_signed_pointer (struct gdbarch *gdbarch, struct type *type,
341 gdb_byte *buf, CORE_ADDR addr)
343 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
345 store_signed_integer (buf, TYPE_LENGTH (type), byte_order, addr);
350 enum symbol_needs_kind
351 symbol_read_needs (struct symbol *sym)
353 if (SYMBOL_COMPUTED_OPS (sym) != NULL)
354 return SYMBOL_COMPUTED_OPS (sym)->get_symbol_read_needs (sym);
356 switch (SYMBOL_CLASS (sym))
358 /* All cases listed explicitly so that gcc -Wall will detect it if
359 we failed to consider one. */
361 gdb_assert_not_reached (_("LOC_COMPUTED variable missing a method"));
366 case LOC_REGPARM_ADDR:
368 return SYMBOL_NEEDS_FRAME;
376 /* Getting the address of a label can be done independently of the block,
377 even if some *uses* of that address wouldn't work so well without
381 case LOC_CONST_BYTES:
383 case LOC_OPTIMIZED_OUT:
384 return SYMBOL_NEEDS_NONE;
386 return SYMBOL_NEEDS_FRAME;
392 symbol_read_needs_frame (struct symbol *sym)
394 return symbol_read_needs (sym) == SYMBOL_NEEDS_FRAME;
397 /* Private data to be used with minsym_lookup_iterator_cb. */
399 struct minsym_lookup_data
401 /* The name of the minimal symbol we are searching for. */
404 /* The field where the callback should store the minimal symbol
405 if found. It should be initialized to NULL before the search
407 struct bound_minimal_symbol result;
410 /* A callback function for gdbarch_iterate_over_objfiles_in_search_order.
411 It searches by name for a minimal symbol within the given OBJFILE.
412 The arguments are passed via CB_DATA, which in reality is a pointer
413 to struct minsym_lookup_data. */
416 minsym_lookup_iterator_cb (struct objfile *objfile, void *cb_data)
418 struct minsym_lookup_data *data = (struct minsym_lookup_data *) cb_data;
420 gdb_assert (data->result.minsym == NULL);
422 data->result = lookup_minimal_symbol (data->name, NULL, objfile);
424 /* The iterator should stop iff a match was found. */
425 return (data->result.minsym != NULL);
428 /* Given static link expression and the frame it lives in, look for the frame
429 the static links points to and return it. Return NULL if we could not find
432 static struct frame_info *
433 follow_static_link (struct frame_info *frame,
434 const struct dynamic_prop *static_link)
436 CORE_ADDR upper_frame_base;
438 if (!dwarf2_evaluate_property (static_link, frame, NULL, &upper_frame_base))
441 /* Now climb up the stack frame until we reach the frame we are interested
443 for (; frame != NULL; frame = get_prev_frame (frame))
445 struct symbol *framefunc = get_frame_function (frame);
447 /* Stacks can be quite deep: give the user a chance to stop this. */
450 /* If we don't know how to compute FRAME's base address, don't give up:
451 maybe the frame we are looking for is upper in the stace frame. */
452 if (framefunc != NULL
453 && SYMBOL_BLOCK_OPS (framefunc) != NULL
454 && SYMBOL_BLOCK_OPS (framefunc)->get_frame_base != NULL
455 && (SYMBOL_BLOCK_OPS (framefunc)->get_frame_base (framefunc, frame)
456 == upper_frame_base))
463 /* Assuming VAR is a symbol that can be reached from FRAME thanks to lexical
464 rules, look for the frame that is actually hosting VAR and return it. If,
465 for some reason, we found no such frame, return NULL.
467 This kind of computation is necessary to correctly handle lexically nested
470 Note that in some cases, we know what scope VAR comes from but we cannot
471 reach the specific frame that hosts the instance of VAR we are looking for.
472 For backward compatibility purposes (with old compilers), we then look for
473 the first frame that can host it. */
475 static struct frame_info *
476 get_hosting_frame (struct symbol *var, const struct block *var_block,
477 struct frame_info *frame)
479 const struct block *frame_block = NULL;
481 if (!symbol_read_needs_frame (var))
484 /* Some symbols for local variables have no block: this happens when they are
485 not produced by a debug information reader, for instance when GDB creates
486 synthetic symbols. Without block information, we must assume they are
487 local to FRAME. In this case, there is nothing to do. */
488 else if (var_block == NULL)
491 /* We currently assume that all symbols with a location list need a frame.
492 This is true in practice because selecting the location description
493 requires to compute the CFA, hence requires a frame. However we have
494 tests that embed global/static symbols with null location lists.
495 We want to get <optimized out> instead of <frame required> when evaluating
496 them so return a frame instead of raising an error. */
497 else if (var_block == block_global_block (var_block)
498 || var_block == block_static_block (var_block))
501 /* We have to handle the "my_func::my_local_var" notation. This requires us
502 to look for upper frames when we find no block for the current frame: here
503 and below, handle when frame_block == NULL. */
505 frame_block = get_frame_block (frame, NULL);
507 /* Climb up the call stack until reaching the frame we are looking for. */
508 while (frame != NULL && frame_block != var_block)
510 /* Stacks can be quite deep: give the user a chance to stop this. */
513 if (frame_block == NULL)
515 frame = get_prev_frame (frame);
518 frame_block = get_frame_block (frame, NULL);
521 /* If we failed to find the proper frame, fallback to the heuristic
523 else if (frame_block == block_global_block (frame_block))
529 /* Assuming we have a block for this frame: if we are at the function
530 level, the immediate upper lexical block is in an outer function:
531 follow the static link. */
532 else if (BLOCK_FUNCTION (frame_block))
534 const struct dynamic_prop *static_link
535 = block_static_link (frame_block);
536 int could_climb_up = 0;
538 if (static_link != NULL)
540 frame = follow_static_link (frame, static_link);
543 frame_block = get_frame_block (frame, NULL);
544 could_climb_up = frame_block != NULL;
555 /* We must be in some function nested lexical block. Just get the
556 outer block: both must share the same frame. */
557 frame_block = BLOCK_SUPERBLOCK (frame_block);
560 /* Old compilers may not provide a static link, or they may provide an
561 invalid one. For such cases, fallback on the old way to evaluate
562 non-local references: just climb up the call stack and pick the first
563 frame that contains the variable we are looking for. */
566 frame = block_innermost_frame (var_block);
569 if (BLOCK_FUNCTION (var_block)
570 && !block_inlined_p (var_block)
571 && SYMBOL_PRINT_NAME (BLOCK_FUNCTION (var_block)))
572 error (_("No frame is currently executing in block %s."),
573 SYMBOL_PRINT_NAME (BLOCK_FUNCTION (var_block)));
575 error (_("No frame is currently executing in specified"
583 /* A default implementation for the "la_read_var_value" hook in
584 the language vector which should work in most situations. */
587 default_read_var_value (struct symbol *var, const struct block *var_block,
588 struct frame_info *frame)
591 struct type *type = SYMBOL_TYPE (var);
593 enum symbol_needs_kind sym_need;
595 /* Call check_typedef on our type to make sure that, if TYPE is
596 a TYPE_CODE_TYPEDEF, its length is set to the length of the target type
597 instead of zero. However, we do not replace the typedef type by the
598 target type, because we want to keep the typedef in order to be able to
599 set the returned value type description correctly. */
600 check_typedef (type);
602 sym_need = symbol_read_needs (var);
603 if (sym_need == SYMBOL_NEEDS_FRAME)
604 gdb_assert (frame != NULL);
605 else if (sym_need == SYMBOL_NEEDS_REGISTERS && !target_has_registers)
606 error (_("Cannot read `%s' without registers"), SYMBOL_PRINT_NAME (var));
609 frame = get_hosting_frame (var, var_block, frame);
611 if (SYMBOL_COMPUTED_OPS (var) != NULL)
612 return SYMBOL_COMPUTED_OPS (var)->read_variable (var, frame);
614 switch (SYMBOL_CLASS (var))
617 if (is_dynamic_type (type))
619 /* Value is a constant byte-sequence and needs no memory access. */
620 type = resolve_dynamic_type (type, NULL, /* Unused address. */ 0);
622 /* Put the constant back in target format. */
623 v = allocate_value (type);
624 store_signed_integer (value_contents_raw (v), TYPE_LENGTH (type),
625 gdbarch_byte_order (get_type_arch (type)),
626 (LONGEST) SYMBOL_VALUE (var));
627 VALUE_LVAL (v) = not_lval;
631 /* Put the constant back in target format. */
632 v = allocate_value (type);
633 if (overlay_debugging)
636 = symbol_overlayed_address (SYMBOL_VALUE_ADDRESS (var),
637 SYMBOL_OBJ_SECTION (symbol_objfile (var),
640 store_typed_address (value_contents_raw (v), type, addr);
643 store_typed_address (value_contents_raw (v), type,
644 SYMBOL_VALUE_ADDRESS (var));
645 VALUE_LVAL (v) = not_lval;
648 case LOC_CONST_BYTES:
649 if (is_dynamic_type (type))
651 /* Value is a constant byte-sequence and needs no memory access. */
652 type = resolve_dynamic_type (type, NULL, /* Unused address. */ 0);
654 v = allocate_value (type);
655 memcpy (value_contents_raw (v), SYMBOL_VALUE_BYTES (var),
657 VALUE_LVAL (v) = not_lval;
661 if (overlay_debugging)
662 addr = symbol_overlayed_address (SYMBOL_VALUE_ADDRESS (var),
663 SYMBOL_OBJ_SECTION (symbol_objfile (var),
666 addr = SYMBOL_VALUE_ADDRESS (var);
670 addr = get_frame_args_address (frame);
672 error (_("Unknown argument list address for `%s'."),
673 SYMBOL_PRINT_NAME (var));
674 addr += SYMBOL_VALUE (var);
682 argref = get_frame_args_address (frame);
684 error (_("Unknown argument list address for `%s'."),
685 SYMBOL_PRINT_NAME (var));
686 argref += SYMBOL_VALUE (var);
687 ref = value_at (lookup_pointer_type (type), argref);
688 addr = value_as_address (ref);
693 addr = get_frame_locals_address (frame);
694 addr += SYMBOL_VALUE (var);
698 error (_("Cannot look up value of a typedef `%s'."),
699 SYMBOL_PRINT_NAME (var));
703 if (overlay_debugging)
704 addr = symbol_overlayed_address
705 (BLOCK_START (SYMBOL_BLOCK_VALUE (var)),
706 SYMBOL_OBJ_SECTION (symbol_objfile (var), var));
708 addr = BLOCK_START (SYMBOL_BLOCK_VALUE (var));
712 case LOC_REGPARM_ADDR:
714 int regno = SYMBOL_REGISTER_OPS (var)
715 ->register_number (var, get_frame_arch (frame));
716 struct value *regval;
718 if (SYMBOL_CLASS (var) == LOC_REGPARM_ADDR)
720 regval = value_from_register (lookup_pointer_type (type),
725 error (_("Value of register variable not available for `%s'."),
726 SYMBOL_PRINT_NAME (var));
728 addr = value_as_address (regval);
732 regval = value_from_register (type, regno, frame);
735 error (_("Value of register variable not available for `%s'."),
736 SYMBOL_PRINT_NAME (var));
743 gdb_assert_not_reached (_("LOC_COMPUTED variable missing a method"));
747 struct minsym_lookup_data lookup_data;
748 struct minimal_symbol *msym;
749 struct obj_section *obj_section;
751 memset (&lookup_data, 0, sizeof (lookup_data));
752 lookup_data.name = SYMBOL_LINKAGE_NAME (var);
754 gdbarch_iterate_over_objfiles_in_search_order
756 minsym_lookup_iterator_cb, &lookup_data,
757 symbol_objfile (var));
758 msym = lookup_data.result.minsym;
760 /* If we can't find the minsym there's a problem in the symbol info.
761 The symbol exists in the debug info, but it's missing in the minsym
765 const char *flavour_name
766 = objfile_flavour_name (symbol_objfile (var));
768 /* We can't get here unless we've opened the file, so flavour_name
770 gdb_assert (flavour_name != NULL);
771 error (_("Missing %s symbol \"%s\"."),
772 flavour_name, SYMBOL_LINKAGE_NAME (var));
774 obj_section = MSYMBOL_OBJ_SECTION (lookup_data.result.objfile, msym);
775 /* Relocate address, unless there is no section or the variable is
777 if (obj_section == NULL
778 || (obj_section->the_bfd_section->flags & SEC_THREAD_LOCAL) != 0)
779 addr = MSYMBOL_VALUE_RAW_ADDRESS (msym);
781 addr = BMSYMBOL_VALUE_ADDRESS (lookup_data.result);
782 if (overlay_debugging)
783 addr = symbol_overlayed_address (addr, obj_section);
784 /* Determine address of TLS variable. */
786 && (obj_section->the_bfd_section->flags & SEC_THREAD_LOCAL) != 0)
787 addr = target_translate_tls_address (obj_section->objfile, addr);
791 case LOC_OPTIMIZED_OUT:
792 if (is_dynamic_type (type))
793 type = resolve_dynamic_type (type, NULL, /* Unused address. */ 0);
794 return allocate_optimized_out_value (type);
797 error (_("Cannot look up value of a botched symbol `%s'."),
798 SYMBOL_PRINT_NAME (var));
802 v = value_at_lazy (type, addr);
806 /* Calls VAR's language la_read_var_value hook with the given arguments. */
809 read_var_value (struct symbol *var, const struct block *var_block,
810 struct frame_info *frame)
812 const struct language_defn *lang = language_def (SYMBOL_LANGUAGE (var));
814 gdb_assert (lang != NULL);
815 gdb_assert (lang->la_read_var_value != NULL);
817 return lang->la_read_var_value (var, var_block, frame);
820 /* Install default attributes for register values. */
823 default_value_from_register (struct gdbarch *gdbarch, struct type *type,
824 int regnum, struct frame_id frame_id)
826 int len = TYPE_LENGTH (type);
827 struct value *value = allocate_value (type);
828 struct frame_info *frame;
830 VALUE_LVAL (value) = lval_register;
831 frame = frame_find_by_id (frame_id);
834 frame_id = null_frame_id;
836 frame_id = get_frame_id (get_next_frame_sentinel_okay (frame));
838 VALUE_NEXT_FRAME_ID (value) = frame_id;
839 VALUE_REGNUM (value) = regnum;
841 /* Any structure stored in more than one register will always be
842 an integral number of registers. Otherwise, you need to do
843 some fiddling with the last register copied here for little
845 if (gdbarch_byte_order (gdbarch) == BFD_ENDIAN_BIG
846 && len < register_size (gdbarch, regnum))
847 /* Big-endian, and we want less than full size. */
848 set_value_offset (value, register_size (gdbarch, regnum) - len);
850 set_value_offset (value, 0);
855 /* VALUE must be an lval_register value. If regnum is the value's
856 associated register number, and len the length of the values type,
857 read one or more registers in FRAME, starting with register REGNUM,
858 until we've read LEN bytes.
860 If any of the registers we try to read are optimized out, then mark the
861 complete resulting value as optimized out. */
864 read_frame_register_value (struct value *value, struct frame_info *frame)
866 struct gdbarch *gdbarch = get_frame_arch (frame);
868 LONGEST reg_offset = value_offset (value);
869 int regnum = VALUE_REGNUM (value);
870 int len = type_length_units (check_typedef (value_type (value)));
872 gdb_assert (VALUE_LVAL (value) == lval_register);
874 /* Skip registers wholly inside of REG_OFFSET. */
875 while (reg_offset >= register_size (gdbarch, regnum))
877 reg_offset -= register_size (gdbarch, regnum);
884 struct value *regval = get_frame_register_value (frame, regnum);
885 int reg_len = type_length_units (value_type (regval)) - reg_offset;
887 /* If the register length is larger than the number of bytes
888 remaining to copy, then only copy the appropriate bytes. */
892 value_contents_copy (value, offset, regval, reg_offset, reg_len);
901 /* Return a value of type TYPE, stored in register REGNUM, in frame FRAME. */
904 value_from_register (struct type *type, int regnum, struct frame_info *frame)
906 struct gdbarch *gdbarch = get_frame_arch (frame);
907 struct type *type1 = check_typedef (type);
910 if (gdbarch_convert_register_p (gdbarch, regnum, type1))
912 int optim, unavail, ok;
914 /* The ISA/ABI need to something weird when obtaining the
915 specified value from this register. It might need to
916 re-order non-adjacent, starting with REGNUM (see MIPS and
917 i386). It might need to convert the [float] register into
918 the corresponding [integer] type (see Alpha). The assumption
919 is that gdbarch_register_to_value populates the entire value
920 including the location. */
921 v = allocate_value (type);
922 VALUE_LVAL (v) = lval_register;
923 VALUE_NEXT_FRAME_ID (v) = get_frame_id (get_next_frame_sentinel_okay (frame));
924 VALUE_REGNUM (v) = regnum;
925 ok = gdbarch_register_to_value (gdbarch, frame, regnum, type1,
926 value_contents_raw (v), &optim,
932 mark_value_bytes_optimized_out (v, 0, TYPE_LENGTH (type));
934 mark_value_bytes_unavailable (v, 0, TYPE_LENGTH (type));
939 /* Construct the value. */
940 v = gdbarch_value_from_register (gdbarch, type,
941 regnum, get_frame_id (frame));
944 read_frame_register_value (v, frame);
950 /* Return contents of register REGNUM in frame FRAME as address.
951 Will abort if register value is not available. */
954 address_from_register (int regnum, struct frame_info *frame)
956 struct gdbarch *gdbarch = get_frame_arch (frame);
957 struct type *type = builtin_type (gdbarch)->builtin_data_ptr;
960 int regnum_max_excl = (gdbarch_num_regs (gdbarch)
961 + gdbarch_num_pseudo_regs (gdbarch));
963 if (regnum < 0 || regnum >= regnum_max_excl)
964 error (_("Invalid register #%d, expecting 0 <= # < %d"), regnum,
967 /* This routine may be called during early unwinding, at a time
968 where the ID of FRAME is not yet known. Calling value_from_register
969 would therefore abort in get_frame_id. However, since we only need
970 a temporary value that is never used as lvalue, we actually do not
971 really need to set its VALUE_NEXT_FRAME_ID. Therefore, we re-implement
972 the core of value_from_register, but use the null_frame_id. */
974 /* Some targets require a special conversion routine even for plain
975 pointer types. Avoid constructing a value object in those cases. */
976 if (gdbarch_convert_register_p (gdbarch, regnum, type))
978 gdb_byte *buf = (gdb_byte *) alloca (TYPE_LENGTH (type));
979 int optim, unavail, ok;
981 ok = gdbarch_register_to_value (gdbarch, frame, regnum, type,
982 buf, &optim, &unavail);
985 /* This function is used while computing a location expression.
986 Complain about the value being optimized out, rather than
987 letting value_as_address complain about some random register
988 the expression depends on not being saved. */
989 error_value_optimized_out ();
992 return unpack_long (type, buf);
995 value = gdbarch_value_from_register (gdbarch, type, regnum, null_frame_id);
996 read_frame_register_value (value, frame);
998 if (value_optimized_out (value))
1000 /* This function is used while computing a location expression.
1001 Complain about the value being optimized out, rather than
1002 letting value_as_address complain about some random register
1003 the expression depends on not being saved. */
1004 error_value_optimized_out ();
1007 result = value_as_address (value);
1008 release_value (value);
1014 namespace selftests {
1015 namespace findvar_tests {
1017 /* Function to test copy_integer_to_size. Store SOURCE_VAL with size
1018 SOURCE_SIZE to a buffer, making sure no sign extending happens at this
1019 stage. Copy buffer to a new buffer using copy_integer_to_size. Extract
1020 copied value and compare to DEST_VALU. Copy again with a signed
1021 copy_integer_to_size and compare to DEST_VALS. Do everything for both
1022 LITTLE and BIG target endians. Use unsigned values throughout to make
1023 sure there are no implicit sign extensions. */
1026 do_cint_test (ULONGEST dest_valu, ULONGEST dest_vals, int dest_size,
1027 ULONGEST src_val, int src_size)
1029 for (int i = 0; i < 2 ; i++)
1031 gdb_byte srcbuf[sizeof (ULONGEST)] = {};
1032 gdb_byte destbuf[sizeof (ULONGEST)] = {};
1033 enum bfd_endian byte_order = i ? BFD_ENDIAN_BIG : BFD_ENDIAN_LITTLE;
1035 /* Fill the src buffer (and later the dest buffer) with non-zero junk,
1036 to ensure zero extensions aren't hidden. */
1037 memset (srcbuf, 0xaa, sizeof (srcbuf));
1039 /* Store (and later extract) using unsigned to ensure there are no sign
1041 store_unsigned_integer (srcbuf, src_size, byte_order, src_val);
1043 /* Test unsigned. */
1044 memset (destbuf, 0xaa, sizeof (destbuf));
1045 copy_integer_to_size (destbuf, dest_size, srcbuf, src_size, false,
1047 SELF_CHECK (dest_valu == extract_unsigned_integer (destbuf, dest_size,
1051 memset (destbuf, 0xaa, sizeof (destbuf));
1052 copy_integer_to_size (destbuf, dest_size, srcbuf, src_size, true,
1054 SELF_CHECK (dest_vals == extract_unsigned_integer (destbuf, dest_size,
1060 copy_integer_to_size_test ()
1062 /* Destination is bigger than the source, which has the signed bit unset. */
1063 do_cint_test (0x12345678, 0x12345678, 8, 0x12345678, 4);
1064 do_cint_test (0x345678, 0x345678, 8, 0x12345678, 3);
1066 /* Destination is bigger than the source, which has the signed bit set. */
1067 do_cint_test (0xdeadbeef, 0xffffffffdeadbeef, 8, 0xdeadbeef, 4);
1068 do_cint_test (0xadbeef, 0xffffffffffadbeef, 8, 0xdeadbeef, 3);
1070 /* Destination is smaller than the source. */
1071 do_cint_test (0x5678, 0x5678, 2, 0x12345678, 3);
1072 do_cint_test (0xbeef, 0xbeef, 2, 0xdeadbeef, 3);
1074 /* Destination and source are the same size. */
1075 do_cint_test (0x8765432112345678, 0x8765432112345678, 8, 0x8765432112345678,
1077 do_cint_test (0x432112345678, 0x432112345678, 6, 0x8765432112345678, 6);
1078 do_cint_test (0xfeedbeaddeadbeef, 0xfeedbeaddeadbeef, 8, 0xfeedbeaddeadbeef,
1080 do_cint_test (0xbeaddeadbeef, 0xbeaddeadbeef, 6, 0xfeedbeaddeadbeef, 6);
1082 /* Destination is bigger than the source. Source is bigger than 32bits. */
1083 do_cint_test (0x3412345678, 0x3412345678, 8, 0x3412345678, 6);
1084 do_cint_test (0xff12345678, 0xff12345678, 8, 0xff12345678, 6);
1085 do_cint_test (0x432112345678, 0x432112345678, 8, 0x8765432112345678, 6);
1086 do_cint_test (0xff2112345678, 0xffffff2112345678, 8, 0xffffff2112345678, 6);
1089 } // namespace findvar_test
1090 } // namespace selftests
1095 _initialize_findvar (void)
1098 selftests::register_test
1099 ("copy_integer_to_size",
1100 selftests::findvar_tests::copy_integer_to_size_test);