1 /* Find a variable's value in memory, for GDB, the GNU debugger.
3 Copyright (C) 1986-2023 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/>. */
30 #include "user-regs.h"
34 #include "dwarf2/loc.h"
35 #include "gdbsupport/selftest.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 (gdb::array_view
<const gdb_byte
> buf
, enum bfd_endian byte_order
)
53 typename
std::make_unsigned
<T
>::type retval
= 0;
55 if (buf
.size () > (int) sizeof (T
))
57 That operation is not available on integers of more than %d bytes."),
60 /* Start at the most significant end of the integer, and work towards
61 the least significant. */
62 if (byte_order
== BFD_ENDIAN_BIG
)
66 if (std::is_signed
<T
>::value
)
68 /* Do the sign extension once at the start. */
69 retval
= ((LONGEST
) buf
[i
] ^ 0x80) - 0x80;
72 for (; i
< buf
.size (); ++i
)
73 retval
= (retval
<< 8) | buf
[i
];
77 ssize_t i
= buf
.size () - 1;
79 if (std::is_signed
<T
>::value
)
81 /* Do the sign extension once at the start. */
82 retval
= ((LONGEST
) buf
[i
] ^ 0x80) - 0x80;
86 retval
= (retval
<< 8) | buf
[i
];
91 /* Explicit instantiations. */
92 template LONGEST extract_integer
<LONGEST
> (gdb::array_view
<const gdb_byte
> buf
,
93 enum bfd_endian byte_order
);
94 template ULONGEST extract_integer
<ULONGEST
>
95 (gdb::array_view
<const gdb_byte
> buf
, enum bfd_endian byte_order
);
97 /* Sometimes a long long unsigned integer can be extracted as a
98 LONGEST value. This is done so that we can print these values
99 better. If this integer can be converted to a LONGEST, this
100 function returns 1 and sets *PVAL. Otherwise it returns 0. */
103 extract_long_unsigned_integer (const gdb_byte
*addr
, int orig_len
,
104 enum bfd_endian byte_order
, LONGEST
*pval
)
107 const gdb_byte
*first_addr
;
111 if (byte_order
== BFD_ENDIAN_BIG
)
114 len
> (int) sizeof (LONGEST
) && p
< addr
+ orig_len
;
127 for (p
= addr
+ orig_len
- 1;
128 len
> (int) sizeof (LONGEST
) && p
>= addr
;
138 if (len
<= (int) sizeof (LONGEST
))
140 *pval
= (LONGEST
) extract_unsigned_integer (first_addr
,
150 /* Treat the bytes at BUF as a pointer of type TYPE, and return the
151 address it represents. */
153 extract_typed_address (const gdb_byte
*buf
, struct type
*type
)
155 gdb_assert (type
->is_pointer_or_reference ());
156 return gdbarch_pointer_to_address (type
->arch (), type
, buf
);
159 /* All 'store' functions accept a host-format integer and store a
160 target-format integer at ADDR which is LEN bytes long. */
161 template<typename T
, typename
>
163 store_integer (gdb_byte
*addr
, int len
, enum bfd_endian byte_order
,
167 gdb_byte
*startaddr
= addr
;
168 gdb_byte
*endaddr
= startaddr
+ len
;
170 /* Start at the least significant end of the integer, and work towards
171 the most significant. */
172 if (byte_order
== BFD_ENDIAN_BIG
)
174 for (p
= endaddr
- 1; p
>= startaddr
; --p
)
182 for (p
= startaddr
; p
< endaddr
; ++p
)
190 /* Explicit instantiations. */
191 template void store_integer (gdb_byte
*addr
, int len
,
192 enum bfd_endian byte_order
,
195 template void store_integer (gdb_byte
*addr
, int len
,
196 enum bfd_endian byte_order
,
199 /* Store the address ADDR as a pointer of type TYPE at BUF, in target
202 store_typed_address (gdb_byte
*buf
, struct type
*type
, CORE_ADDR addr
)
204 gdb_assert (type
->is_pointer_or_reference ());
205 gdbarch_address_to_pointer (type
->arch (), type
, buf
, addr
);
208 /* Copy a value from SOURCE of size SOURCE_SIZE bytes to DEST of size DEST_SIZE
209 bytes. If SOURCE_SIZE is greater than DEST_SIZE, then truncate the most
210 significant bytes. If SOURCE_SIZE is less than DEST_SIZE then either sign
211 or zero extended according to IS_SIGNED. Values are stored in memory with
212 endianness BYTE_ORDER. */
215 copy_integer_to_size (gdb_byte
*dest
, int dest_size
, const gdb_byte
*source
,
216 int source_size
, bool is_signed
,
217 enum bfd_endian byte_order
)
219 signed int size_diff
= dest_size
- source_size
;
221 /* Copy across everything from SOURCE that can fit into DEST. */
223 if (byte_order
== BFD_ENDIAN_BIG
&& size_diff
> 0)
224 memcpy (dest
+ size_diff
, source
, source_size
);
225 else if (byte_order
== BFD_ENDIAN_BIG
&& size_diff
< 0)
226 memcpy (dest
, source
- size_diff
, dest_size
);
228 memcpy (dest
, source
, std::min (source_size
, dest_size
));
230 /* Fill the remaining space in DEST by either zero extending or sign
235 gdb_byte extension
= 0;
237 && ((byte_order
!= BFD_ENDIAN_BIG
&& source
[source_size
- 1] & 0x80)
238 || (byte_order
== BFD_ENDIAN_BIG
&& source
[0] & 0x80)))
241 /* Extend into MSBs of SOURCE. */
242 if (byte_order
== BFD_ENDIAN_BIG
)
243 memset (dest
, extension
, size_diff
);
245 memset (dest
+ source_size
, extension
, size_diff
);
249 /* Return a `value' with the contents of (virtual or cooked) register
250 REGNUM as found in the specified FRAME. The register's type is
251 determined by register_type (). */
254 value_of_register (int regnum
, frame_info_ptr frame
)
256 struct gdbarch
*gdbarch
= get_frame_arch (frame
);
257 struct value
*reg_val
;
259 /* User registers lie completely outside of the range of normal
260 registers. Catch them early so that the target never sees them. */
261 if (regnum
>= gdbarch_num_cooked_regs (gdbarch
))
262 return value_of_user_reg (regnum
, frame
);
264 reg_val
= value_of_register_lazy (frame
, regnum
);
265 reg_val
->fetch_lazy ();
269 /* Return a `value' with the contents of (virtual or cooked) register
270 REGNUM as found in the specified FRAME. The register's type is
271 determined by register_type (). The value is not fetched. */
274 value_of_register_lazy (frame_info_ptr frame
, int regnum
)
276 struct gdbarch
*gdbarch
= get_frame_arch (frame
);
277 struct value
*reg_val
;
278 frame_info_ptr next_frame
;
280 gdb_assert (regnum
< gdbarch_num_cooked_regs (gdbarch
));
282 gdb_assert (frame
!= NULL
);
284 next_frame
= get_next_frame_sentinel_okay (frame
);
286 /* In some cases NEXT_FRAME may not have a valid frame-id yet. This can
287 happen if we end up trying to unwind a register as part of the frame
288 sniffer. The only time that we get here without a valid frame-id is
289 if NEXT_FRAME is an inline frame. If this is the case then we can
290 avoid getting into trouble here by skipping past the inline frames. */
291 while (get_frame_type (next_frame
) == INLINE_FRAME
)
292 next_frame
= get_next_frame_sentinel_okay (next_frame
);
294 /* We should have a valid next frame. */
295 gdb_assert (frame_id_p (get_frame_id (next_frame
)));
297 reg_val
= value::allocate_lazy (register_type (gdbarch
, regnum
));
298 reg_val
->set_lval (lval_register
);
299 VALUE_REGNUM (reg_val
) = regnum
;
300 VALUE_NEXT_FRAME_ID (reg_val
) = get_frame_id (next_frame
);
305 /* Given a pointer of type TYPE in target form in BUF, return the
306 address it represents. */
308 unsigned_pointer_to_address (struct gdbarch
*gdbarch
,
309 struct type
*type
, const gdb_byte
*buf
)
311 enum bfd_endian byte_order
= type_byte_order (type
);
313 return extract_unsigned_integer (buf
, type
->length (), byte_order
);
317 signed_pointer_to_address (struct gdbarch
*gdbarch
,
318 struct type
*type
, const gdb_byte
*buf
)
320 enum bfd_endian byte_order
= type_byte_order (type
);
322 return extract_signed_integer (buf
, type
->length (), byte_order
);
325 /* Given an address, store it as a pointer of type TYPE in target
328 unsigned_address_to_pointer (struct gdbarch
*gdbarch
, struct type
*type
,
329 gdb_byte
*buf
, CORE_ADDR addr
)
331 enum bfd_endian byte_order
= type_byte_order (type
);
333 store_unsigned_integer (buf
, type
->length (), byte_order
, addr
);
337 address_to_signed_pointer (struct gdbarch
*gdbarch
, struct type
*type
,
338 gdb_byte
*buf
, CORE_ADDR addr
)
340 enum bfd_endian byte_order
= type_byte_order (type
);
342 store_signed_integer (buf
, type
->length (), byte_order
, addr
);
347 enum symbol_needs_kind
348 symbol_read_needs (struct symbol
*sym
)
350 if (SYMBOL_COMPUTED_OPS (sym
) != NULL
)
351 return SYMBOL_COMPUTED_OPS (sym
)->get_symbol_read_needs (sym
);
353 switch (sym
->aclass ())
355 /* All cases listed explicitly so that gcc -Wall will detect it if
356 we failed to consider one. */
358 gdb_assert_not_reached ("LOC_COMPUTED variable missing a method");
363 case LOC_REGPARM_ADDR
:
365 return SYMBOL_NEEDS_FRAME
;
373 /* Getting the address of a label can be done independently of the block,
374 even if some *uses* of that address wouldn't work so well without
378 case LOC_CONST_BYTES
:
380 case LOC_OPTIMIZED_OUT
:
381 return SYMBOL_NEEDS_NONE
;
383 return SYMBOL_NEEDS_FRAME
;
389 symbol_read_needs_frame (struct symbol
*sym
)
391 return symbol_read_needs (sym
) == SYMBOL_NEEDS_FRAME
;
394 /* Given static link expression and the frame it lives in, look for the frame
395 the static links points to and return it. Return NULL if we could not find
398 static frame_info_ptr
399 follow_static_link (frame_info_ptr frame
,
400 const struct dynamic_prop
*static_link
)
402 CORE_ADDR upper_frame_base
;
404 if (!dwarf2_evaluate_property (static_link
, frame
, NULL
, &upper_frame_base
))
407 /* Now climb up the stack frame until we reach the frame we are interested
409 for (; frame
!= NULL
; frame
= get_prev_frame (frame
))
411 struct symbol
*framefunc
= get_frame_function (frame
);
413 /* Stacks can be quite deep: give the user a chance to stop this. */
416 /* If we don't know how to compute FRAME's base address, don't give up:
417 maybe the frame we are looking for is upper in the stack frame. */
418 if (framefunc
!= NULL
419 && SYMBOL_BLOCK_OPS (framefunc
) != NULL
420 && SYMBOL_BLOCK_OPS (framefunc
)->get_frame_base
!= NULL
421 && (SYMBOL_BLOCK_OPS (framefunc
)->get_frame_base (framefunc
, frame
)
422 == upper_frame_base
))
429 /* Assuming VAR is a symbol that can be reached from FRAME thanks to lexical
430 rules, look for the frame that is actually hosting VAR and return it. If,
431 for some reason, we found no such frame, return NULL.
433 This kind of computation is necessary to correctly handle lexically nested
436 Note that in some cases, we know what scope VAR comes from but we cannot
437 reach the specific frame that hosts the instance of VAR we are looking for.
438 For backward compatibility purposes (with old compilers), we then look for
439 the first frame that can host it. */
441 static frame_info_ptr
442 get_hosting_frame (struct symbol
*var
, const struct block
*var_block
,
443 frame_info_ptr frame
)
445 const struct block
*frame_block
= NULL
;
447 if (!symbol_read_needs_frame (var
))
450 /* Some symbols for local variables have no block: this happens when they are
451 not produced by a debug information reader, for instance when GDB creates
452 synthetic symbols. Without block information, we must assume they are
453 local to FRAME. In this case, there is nothing to do. */
454 else if (var_block
== NULL
)
457 /* We currently assume that all symbols with a location list need a frame.
458 This is true in practice because selecting the location description
459 requires to compute the CFA, hence requires a frame. However we have
460 tests that embed global/static symbols with null location lists.
461 We want to get <optimized out> instead of <frame required> when evaluating
462 them so return a frame instead of raising an error. */
463 else if (var_block
->is_global_block () || var_block
->is_static_block ())
466 /* We have to handle the "my_func::my_local_var" notation. This requires us
467 to look for upper frames when we find no block for the current frame: here
468 and below, handle when frame_block == NULL. */
470 frame_block
= get_frame_block (frame
, NULL
);
472 /* Climb up the call stack until reaching the frame we are looking for. */
473 while (frame
!= NULL
&& frame_block
!= var_block
)
475 /* Stacks can be quite deep: give the user a chance to stop this. */
478 if (frame_block
== NULL
)
480 frame
= get_prev_frame (frame
);
483 frame_block
= get_frame_block (frame
, NULL
);
486 /* If we failed to find the proper frame, fallback to the heuristic
488 else if (frame_block
->is_global_block ())
494 /* Assuming we have a block for this frame: if we are at the function
495 level, the immediate upper lexical block is in an outer function:
496 follow the static link. */
497 else if (frame_block
->function ())
499 const struct dynamic_prop
*static_link
500 = frame_block
->static_link ();
501 int could_climb_up
= 0;
503 if (static_link
!= NULL
)
505 frame
= follow_static_link (frame
, static_link
);
508 frame_block
= get_frame_block (frame
, NULL
);
509 could_climb_up
= frame_block
!= NULL
;
520 /* We must be in some function nested lexical block. Just get the
521 outer block: both must share the same frame. */
522 frame_block
= frame_block
->superblock ();
525 /* Old compilers may not provide a static link, or they may provide an
526 invalid one. For such cases, fallback on the old way to evaluate
527 non-local references: just climb up the call stack and pick the first
528 frame that contains the variable we are looking for. */
531 frame
= block_innermost_frame (var_block
);
534 if (var_block
->function ()
535 && !var_block
->inlined_p ()
536 && var_block
->function ()->print_name ())
537 error (_("No frame is currently executing in block %s."),
538 var_block
->function ()->print_name ());
540 error (_("No frame is currently executing in specified"
548 /* See language.h. */
551 language_defn::read_var_value (struct symbol
*var
,
552 const struct block
*var_block
,
553 frame_info_ptr frame
) const
556 struct type
*type
= var
->type ();
558 enum symbol_needs_kind sym_need
;
560 /* Call check_typedef on our type to make sure that, if TYPE is
561 a TYPE_CODE_TYPEDEF, its length is set to the length of the target type
562 instead of zero. However, we do not replace the typedef type by the
563 target type, because we want to keep the typedef in order to be able to
564 set the returned value type description correctly. */
565 check_typedef (type
);
567 sym_need
= symbol_read_needs (var
);
568 if (sym_need
== SYMBOL_NEEDS_FRAME
)
569 gdb_assert (frame
!= NULL
);
570 else if (sym_need
== SYMBOL_NEEDS_REGISTERS
&& !target_has_registers ())
571 error (_("Cannot read `%s' without registers"), var
->print_name ());
574 frame
= get_hosting_frame (var
, var_block
, frame
);
576 if (SYMBOL_COMPUTED_OPS (var
) != NULL
)
577 return SYMBOL_COMPUTED_OPS (var
)->read_variable (var
, frame
);
579 switch (var
->aclass ())
582 if (is_dynamic_type (type
))
584 /* Value is a constant byte-sequence and needs no memory access. */
585 type
= resolve_dynamic_type (type
, {}, /* Unused address. */ 0);
587 /* Put the constant back in target format. */
588 v
= value::allocate (type
);
589 store_signed_integer (v
->contents_raw ().data (), type
->length (),
590 type_byte_order (type
), var
->value_longest ());
591 v
->set_lval (not_lval
);
596 /* Put the constant back in target format. */
597 if (overlay_debugging
)
599 struct objfile
*var_objfile
= var
->objfile ();
600 addr
= symbol_overlayed_address (var
->value_address (),
601 var
->obj_section (var_objfile
));
604 addr
= var
->value_address ();
606 /* First convert the CORE_ADDR to a function pointer type, this
607 ensures the gdbarch knows what type of pointer we are
608 manipulating when value_from_pointer is called. */
609 type
= builtin_type (var
->arch ())->builtin_func_ptr
;
610 v
= value_from_pointer (type
, addr
);
612 /* But we want to present the value as 'void *', so cast it to the
613 required type now, this will not change the values bit
615 struct type
*void_ptr_type
616 = builtin_type (var
->arch ())->builtin_data_ptr
;
617 v
= value_cast_pointers (void_ptr_type
, v
, 0);
618 v
->set_lval (not_lval
);
622 case LOC_CONST_BYTES
:
623 if (is_dynamic_type (type
))
625 /* Value is a constant byte-sequence and needs no memory access. */
626 type
= resolve_dynamic_type (type
, {}, /* Unused address. */ 0);
628 v
= value::allocate (type
);
629 memcpy (v
->contents_raw ().data (), var
->value_bytes (),
631 v
->set_lval (not_lval
);
635 if (overlay_debugging
)
637 = symbol_overlayed_address (var
->value_address (),
638 var
->obj_section (var
->objfile ()));
640 addr
= var
->value_address ();
644 addr
= get_frame_args_address (frame
);
646 error (_("Unknown argument list address for `%s'."),
648 addr
+= var
->value_longest ();
656 argref
= get_frame_args_address (frame
);
658 error (_("Unknown argument list address for `%s'."),
660 argref
+= var
->value_longest ();
661 ref
= value_at (lookup_pointer_type (type
), argref
);
662 addr
= value_as_address (ref
);
667 addr
= get_frame_locals_address (frame
);
668 addr
+= var
->value_longest ();
672 error (_("Cannot look up value of a typedef `%s'."),
677 if (overlay_debugging
)
678 addr
= symbol_overlayed_address
679 (var
->value_block ()->entry_pc (),
680 var
->obj_section (var
->objfile ()));
682 addr
= var
->value_block ()->entry_pc ();
686 case LOC_REGPARM_ADDR
:
688 int regno
= SYMBOL_REGISTER_OPS (var
)
689 ->register_number (var
, get_frame_arch (frame
));
690 struct value
*regval
;
692 if (var
->aclass () == LOC_REGPARM_ADDR
)
694 regval
= value_from_register (lookup_pointer_type (type
),
699 error (_("Value of register variable not available for `%s'."),
702 addr
= value_as_address (regval
);
706 regval
= value_from_register (type
, regno
, frame
);
709 error (_("Value of register variable not available for `%s'."),
717 gdb_assert_not_reached ("LOC_COMPUTED variable missing a method");
721 struct obj_section
*obj_section
;
722 bound_minimal_symbol bmsym
;
724 gdbarch_iterate_over_objfiles_in_search_order
726 [var
, &bmsym
] (objfile
*objfile
)
728 bmsym
= lookup_minimal_symbol (var
->linkage_name (), nullptr,
731 /* Stop if a match is found. */
732 return bmsym
.minsym
!= nullptr;
736 /* If we can't find the minsym there's a problem in the symbol info.
737 The symbol exists in the debug info, but it's missing in the minsym
739 if (bmsym
.minsym
== nullptr)
741 const char *flavour_name
742 = objfile_flavour_name (var
->objfile ());
744 /* We can't get here unless we've opened the file, so flavour_name
746 gdb_assert (flavour_name
!= NULL
);
747 error (_("Missing %s symbol \"%s\"."),
748 flavour_name
, var
->linkage_name ());
751 obj_section
= bmsym
.minsym
->obj_section (bmsym
.objfile
);
752 /* Relocate address, unless there is no section or the variable is
754 if (obj_section
== NULL
755 || (obj_section
->the_bfd_section
->flags
& SEC_THREAD_LOCAL
) != 0)
756 addr
= CORE_ADDR (bmsym
.minsym
->unrelocated_address ());
758 addr
= bmsym
.value_address ();
759 if (overlay_debugging
)
760 addr
= symbol_overlayed_address (addr
, obj_section
);
761 /* Determine address of TLS variable. */
763 && (obj_section
->the_bfd_section
->flags
& SEC_THREAD_LOCAL
) != 0)
764 addr
= target_translate_tls_address (obj_section
->objfile
, addr
);
768 case LOC_OPTIMIZED_OUT
:
769 if (is_dynamic_type (type
))
770 type
= resolve_dynamic_type (type
, {}, /* Unused address. */ 0);
771 return value::allocate_optimized_out (type
);
774 error (_("Cannot look up value of a botched symbol `%s'."),
779 v
= value_at_lazy (type
, addr
);
783 /* Calls VAR's language read_var_value hook with the given arguments. */
786 read_var_value (struct symbol
*var
, const struct block
*var_block
,
787 frame_info_ptr frame
)
789 const struct language_defn
*lang
= language_def (var
->language ());
791 gdb_assert (lang
!= NULL
);
793 return lang
->read_var_value (var
, var_block
, frame
);
796 /* Install default attributes for register values. */
799 default_value_from_register (struct gdbarch
*gdbarch
, struct type
*type
,
800 int regnum
, struct frame_id frame_id
)
802 int len
= type
->length ();
803 struct value
*value
= value::allocate (type
);
804 frame_info_ptr frame
;
806 value
->set_lval (lval_register
);
807 frame
= frame_find_by_id (frame_id
);
810 frame_id
= null_frame_id
;
812 frame_id
= get_frame_id (get_next_frame_sentinel_okay (frame
));
814 VALUE_NEXT_FRAME_ID (value
) = frame_id
;
815 VALUE_REGNUM (value
) = regnum
;
817 /* Any structure stored in more than one register will always be
818 an integral number of registers. Otherwise, you need to do
819 some fiddling with the last register copied here for little
821 if (type_byte_order (type
) == BFD_ENDIAN_BIG
822 && len
< register_size (gdbarch
, regnum
))
823 /* Big-endian, and we want less than full size. */
824 value
->set_offset (register_size (gdbarch
, regnum
) - len
);
826 value
->set_offset (0);
831 /* VALUE must be an lval_register value. If regnum is the value's
832 associated register number, and len the length of the values type,
833 read one or more registers in FRAME, starting with register REGNUM,
834 until we've read LEN bytes.
836 If any of the registers we try to read are optimized out, then mark the
837 complete resulting value as optimized out. */
840 read_frame_register_value (struct value
*value
, frame_info_ptr frame
)
842 struct gdbarch
*gdbarch
= get_frame_arch (frame
);
844 LONGEST reg_offset
= value
->offset ();
845 int regnum
= VALUE_REGNUM (value
);
846 int len
= type_length_units (check_typedef (value
->type ()));
848 gdb_assert (value
->lval () == lval_register
);
850 /* Skip registers wholly inside of REG_OFFSET. */
851 while (reg_offset
>= register_size (gdbarch
, regnum
))
853 reg_offset
-= register_size (gdbarch
, regnum
);
860 struct value
*regval
= get_frame_register_value (frame
, regnum
);
861 int reg_len
= type_length_units (regval
->type ()) - reg_offset
;
863 /* If the register length is larger than the number of bytes
864 remaining to copy, then only copy the appropriate bytes. */
868 regval
->contents_copy (value
, offset
, reg_offset
, reg_len
);
877 /* Return a value of type TYPE, stored in register REGNUM, in frame FRAME. */
880 value_from_register (struct type
*type
, int regnum
, frame_info_ptr frame
)
882 struct gdbarch
*gdbarch
= get_frame_arch (frame
);
883 struct type
*type1
= check_typedef (type
);
886 if (gdbarch_convert_register_p (gdbarch
, regnum
, type1
))
888 int optim
, unavail
, ok
;
890 /* The ISA/ABI need to something weird when obtaining the
891 specified value from this register. It might need to
892 re-order non-adjacent, starting with REGNUM (see MIPS and
893 i386). It might need to convert the [float] register into
894 the corresponding [integer] type (see Alpha). The assumption
895 is that gdbarch_register_to_value populates the entire value
896 including the location. */
897 v
= value::allocate (type
);
898 v
->set_lval (lval_register
);
899 VALUE_NEXT_FRAME_ID (v
) = get_frame_id (get_next_frame_sentinel_okay (frame
));
900 VALUE_REGNUM (v
) = regnum
;
901 ok
= gdbarch_register_to_value (gdbarch
, frame
, regnum
, type1
,
902 v
->contents_raw ().data (), &optim
,
908 v
->mark_bytes_optimized_out (0, type
->length ());
910 v
->mark_bytes_unavailable (0, type
->length ());
915 /* Construct the value. */
916 v
= gdbarch_value_from_register (gdbarch
, type
,
917 regnum
, get_frame_id (frame
));
920 read_frame_register_value (v
, frame
);
926 /* Return contents of register REGNUM in frame FRAME as address.
927 Will abort if register value is not available. */
930 address_from_register (int regnum
, frame_info_ptr frame
)
932 struct gdbarch
*gdbarch
= get_frame_arch (frame
);
933 struct type
*type
= builtin_type (gdbarch
)->builtin_data_ptr
;
936 int regnum_max_excl
= gdbarch_num_cooked_regs (gdbarch
);
938 if (regnum
< 0 || regnum
>= regnum_max_excl
)
939 error (_("Invalid register #%d, expecting 0 <= # < %d"), regnum
,
942 /* This routine may be called during early unwinding, at a time
943 where the ID of FRAME is not yet known. Calling value_from_register
944 would therefore abort in get_frame_id. However, since we only need
945 a temporary value that is never used as lvalue, we actually do not
946 really need to set its VALUE_NEXT_FRAME_ID. Therefore, we re-implement
947 the core of value_from_register, but use the null_frame_id. */
949 /* Some targets require a special conversion routine even for plain
950 pointer types. Avoid constructing a value object in those cases. */
951 if (gdbarch_convert_register_p (gdbarch
, regnum
, type
))
953 gdb_byte
*buf
= (gdb_byte
*) alloca (type
->length ());
954 int optim
, unavail
, ok
;
956 ok
= gdbarch_register_to_value (gdbarch
, frame
, regnum
, type
,
957 buf
, &optim
, &unavail
);
960 /* This function is used while computing a location expression.
961 Complain about the value being optimized out, rather than
962 letting value_as_address complain about some random register
963 the expression depends on not being saved. */
964 error_value_optimized_out ();
967 return unpack_long (type
, buf
);
970 value
= gdbarch_value_from_register (gdbarch
, type
, regnum
, null_frame_id
);
971 read_frame_register_value (value
, frame
);
973 if (value
->optimized_out ())
975 /* This function is used while computing a location expression.
976 Complain about the value being optimized out, rather than
977 letting value_as_address complain about some random register
978 the expression depends on not being saved. */
979 error_value_optimized_out ();
982 result
= value_as_address (value
);
983 release_value (value
);
989 namespace selftests
{
990 namespace findvar_tests
{
992 /* Function to test copy_integer_to_size. Store SOURCE_VAL with size
993 SOURCE_SIZE to a buffer, making sure no sign extending happens at this
994 stage. Copy buffer to a new buffer using copy_integer_to_size. Extract
995 copied value and compare to DEST_VALU. Copy again with a signed
996 copy_integer_to_size and compare to DEST_VALS. Do everything for both
997 LITTLE and BIG target endians. Use unsigned values throughout to make
998 sure there are no implicit sign extensions. */
1001 do_cint_test (ULONGEST dest_valu
, ULONGEST dest_vals
, int dest_size
,
1002 ULONGEST src_val
, int src_size
)
1004 for (int i
= 0; i
< 2 ; i
++)
1006 gdb_byte srcbuf
[sizeof (ULONGEST
)] = {};
1007 gdb_byte destbuf
[sizeof (ULONGEST
)] = {};
1008 enum bfd_endian byte_order
= i
? BFD_ENDIAN_BIG
: BFD_ENDIAN_LITTLE
;
1010 /* Fill the src buffer (and later the dest buffer) with non-zero junk,
1011 to ensure zero extensions aren't hidden. */
1012 memset (srcbuf
, 0xaa, sizeof (srcbuf
));
1014 /* Store (and later extract) using unsigned to ensure there are no sign
1016 store_unsigned_integer (srcbuf
, src_size
, byte_order
, src_val
);
1018 /* Test unsigned. */
1019 memset (destbuf
, 0xaa, sizeof (destbuf
));
1020 copy_integer_to_size (destbuf
, dest_size
, srcbuf
, src_size
, false,
1022 SELF_CHECK (dest_valu
== extract_unsigned_integer (destbuf
, dest_size
,
1026 memset (destbuf
, 0xaa, sizeof (destbuf
));
1027 copy_integer_to_size (destbuf
, dest_size
, srcbuf
, src_size
, true,
1029 SELF_CHECK (dest_vals
== extract_unsigned_integer (destbuf
, dest_size
,
1035 copy_integer_to_size_test ()
1037 /* Destination is bigger than the source, which has the signed bit unset. */
1038 do_cint_test (0x12345678, 0x12345678, 8, 0x12345678, 4);
1039 do_cint_test (0x345678, 0x345678, 8, 0x12345678, 3);
1041 /* Destination is bigger than the source, which has the signed bit set. */
1042 do_cint_test (0xdeadbeef, 0xffffffffdeadbeef, 8, 0xdeadbeef, 4);
1043 do_cint_test (0xadbeef, 0xffffffffffadbeef, 8, 0xdeadbeef, 3);
1045 /* Destination is smaller than the source. */
1046 do_cint_test (0x5678, 0x5678, 2, 0x12345678, 3);
1047 do_cint_test (0xbeef, 0xbeef, 2, 0xdeadbeef, 3);
1049 /* Destination and source are the same size. */
1050 do_cint_test (0x8765432112345678, 0x8765432112345678, 8, 0x8765432112345678,
1052 do_cint_test (0x432112345678, 0x432112345678, 6, 0x8765432112345678, 6);
1053 do_cint_test (0xfeedbeaddeadbeef, 0xfeedbeaddeadbeef, 8, 0xfeedbeaddeadbeef,
1055 do_cint_test (0xbeaddeadbeef, 0xbeaddeadbeef, 6, 0xfeedbeaddeadbeef, 6);
1057 /* Destination is bigger than the source. Source is bigger than 32bits. */
1058 do_cint_test (0x3412345678, 0x3412345678, 8, 0x3412345678, 6);
1059 do_cint_test (0xff12345678, 0xff12345678, 8, 0xff12345678, 6);
1060 do_cint_test (0x432112345678, 0x432112345678, 8, 0x8765432112345678, 6);
1061 do_cint_test (0xff2112345678, 0xffffff2112345678, 8, 0xffffff2112345678, 6);
1064 } // namespace findvar_test
1065 } // namespace selftests
1069 void _initialize_findvar ();
1071 _initialize_findvar ()
1074 selftests::register_test
1075 ("copy_integer_to_size",
1076 selftests::findvar_tests::copy_integer_to_size_test
);