1 /* Find a variable's value in memory, for GDB, the GNU debugger.
2 Copyright 1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995,
3 1996, 1997, 1998, 1999, 2000, 2001
4 Free Software Foundation, Inc.
6 This file is part of GDB.
8 This program is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 2 of the License, or
11 (at your option) any later version.
13 This program is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with this program; if not, write to the Free Software
20 Foundation, Inc., 59 Temple Place - Suite 330,
21 Boston, MA 02111-1307, USA. */
31 #include "gdb_string.h"
32 #include "gdb_assert.h"
33 #include "floatformat.h"
34 #include "symfile.h" /* for overlay functions */
36 #include "builtin-regs.h"
38 /* Basic byte-swapping routines. GDB has needed these for a long time...
39 All extract a target-format integer at ADDR which is LEN bytes long. */
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... */
50 extract_signed_integer (const void *addr
, int len
)
53 const unsigned char *p
;
54 const unsigned char *startaddr
= addr
;
55 const unsigned char *endaddr
= startaddr
+ len
;
57 if (len
> (int) sizeof (LONGEST
))
59 That operation is not available on integers of more than %d bytes.",
60 (int) sizeof (LONGEST
));
62 /* Start at the most significant end of the integer, and work towards
63 the least significant. */
64 if (TARGET_BYTE_ORDER
== BFD_ENDIAN_BIG
)
67 /* Do the sign extension once at the start. */
68 retval
= ((LONGEST
) * p
^ 0x80) - 0x80;
69 for (++p
; p
< endaddr
; ++p
)
70 retval
= (retval
<< 8) | *p
;
75 /* Do the sign extension once at the start. */
76 retval
= ((LONGEST
) * p
^ 0x80) - 0x80;
77 for (--p
; p
>= startaddr
; --p
)
78 retval
= (retval
<< 8) | *p
;
84 extract_unsigned_integer (const void *addr
, int len
)
87 const unsigned char *p
;
88 const unsigned char *startaddr
= addr
;
89 const unsigned char *endaddr
= startaddr
+ len
;
91 if (len
> (int) sizeof (ULONGEST
))
93 That operation is not available on integers of more than %d bytes.",
94 (int) sizeof (ULONGEST
));
96 /* Start at the most significant end of the integer, and work towards
97 the least significant. */
99 if (TARGET_BYTE_ORDER
== BFD_ENDIAN_BIG
)
101 for (p
= startaddr
; p
< endaddr
; ++p
)
102 retval
= (retval
<< 8) | *p
;
106 for (p
= endaddr
- 1; p
>= startaddr
; --p
)
107 retval
= (retval
<< 8) | *p
;
112 /* Sometimes a long long unsigned integer can be extracted as a
113 LONGEST value. This is done so that we can print these values
114 better. If this integer can be converted to a LONGEST, this
115 function returns 1 and sets *PVAL. Otherwise it returns 0. */
118 extract_long_unsigned_integer (void *addr
, int orig_len
, LONGEST
*pval
)
120 char *p
, *first_addr
;
124 if (TARGET_BYTE_ORDER
== BFD_ENDIAN_BIG
)
126 for (p
= (char *) addr
;
127 len
> (int) sizeof (LONGEST
) && p
< (char *) addr
+ orig_len
;
139 first_addr
= (char *) addr
;
140 for (p
= (char *) addr
+ orig_len
- 1;
141 len
> (int) sizeof (LONGEST
) && p
>= (char *) addr
;
151 if (len
<= (int) sizeof (LONGEST
))
153 *pval
= (LONGEST
) extract_unsigned_integer (first_addr
,
162 /* Treat the LEN bytes at ADDR as a target-format address, and return
163 that address. ADDR is a buffer in the GDB process, not in the
166 This function should only be used by target-specific code. It
167 assumes that a pointer has the same representation as that thing's
168 address represented as an integer. Some machines use word
169 addresses, or similarly munged things, for certain types of
170 pointers, so that assumption doesn't hold everywhere.
172 Common code should use extract_typed_address instead, or something
173 else based on POINTER_TO_ADDRESS. */
176 extract_address (void *addr
, int len
)
178 /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure
179 whether we want this to be true eventually. */
180 return (CORE_ADDR
) extract_unsigned_integer (addr
, len
);
184 /* Treat the bytes at BUF as a pointer of type TYPE, and return the
185 address it represents. */
187 extract_typed_address (void *buf
, struct type
*type
)
189 if (TYPE_CODE (type
) != TYPE_CODE_PTR
190 && TYPE_CODE (type
) != TYPE_CODE_REF
)
191 internal_error (__FILE__
, __LINE__
,
192 "extract_typed_address: "
193 "type is not a pointer or reference");
195 return POINTER_TO_ADDRESS (type
, buf
);
200 store_signed_integer (void *addr
, int len
, LONGEST val
)
203 unsigned char *startaddr
= (unsigned char *) addr
;
204 unsigned char *endaddr
= startaddr
+ len
;
206 /* Start at the least significant end of the integer, and work towards
207 the most significant. */
208 if (TARGET_BYTE_ORDER
== BFD_ENDIAN_BIG
)
210 for (p
= endaddr
- 1; p
>= startaddr
; --p
)
218 for (p
= startaddr
; p
< endaddr
; ++p
)
227 store_unsigned_integer (void *addr
, int len
, ULONGEST val
)
230 unsigned char *startaddr
= (unsigned char *) addr
;
231 unsigned char *endaddr
= startaddr
+ len
;
233 /* Start at the least significant end of the integer, and work towards
234 the most significant. */
235 if (TARGET_BYTE_ORDER
== BFD_ENDIAN_BIG
)
237 for (p
= endaddr
- 1; p
>= startaddr
; --p
)
245 for (p
= startaddr
; p
< endaddr
; ++p
)
253 /* Store the address VAL as a LEN-byte value in target byte order at
254 ADDR. ADDR is a buffer in the GDB process, not in the inferior.
256 This function should only be used by target-specific code. It
257 assumes that a pointer has the same representation as that thing's
258 address represented as an integer. Some machines use word
259 addresses, or similarly munged things, for certain types of
260 pointers, so that assumption doesn't hold everywhere.
262 Common code should use store_typed_address instead, or something else
263 based on ADDRESS_TO_POINTER. */
265 store_address (void *addr
, int len
, LONGEST val
)
267 store_unsigned_integer (addr
, len
, val
);
271 /* Store the address ADDR as a pointer of type TYPE at BUF, in target
274 store_typed_address (void *buf
, struct type
*type
, CORE_ADDR addr
)
276 if (TYPE_CODE (type
) != TYPE_CODE_PTR
277 && TYPE_CODE (type
) != TYPE_CODE_REF
)
278 internal_error (__FILE__
, __LINE__
,
279 "store_typed_address: "
280 "type is not a pointer or reference");
282 ADDRESS_TO_POINTER (type
, buf
, addr
);
287 /* Return a `value' with the contents of (virtual or cooked) register
288 REGNUM as found in the specified FRAME. The register's type is
289 determined by REGISTER_VIRTUAL_TYPE.
291 NOTE: returns NULL if register value is not available. Caller will
292 check return value or die! */
295 value_of_register (int regnum
, struct frame_info
*frame
)
299 struct value
*reg_val
;
300 char *raw_buffer
= (char*) alloca (MAX_REGISTER_RAW_SIZE
);
303 /* Builtin registers lie completly outside of the range of normal
304 registers. Catch them early so that the target never sees them. */
305 if (regnum
>= NUM_REGS
+ NUM_PSEUDO_REGS
)
306 return value_of_builtin_reg (regnum
, selected_frame
);
308 get_saved_register (raw_buffer
, &optim
, &addr
,
309 frame
, regnum
, &lval
);
311 /* FIXME: cagney/2002-05-15: This test is just bogus.
313 It indicates that the target failed to supply a value for a
314 register because it was "not available" at this time. Problem
315 is, the target still has the register and so get saved_register()
316 may be returning a value saved on the stack. */
318 if (register_cached (regnum
) < 0)
319 return NULL
; /* register value not available */
321 reg_val
= allocate_value (REGISTER_VIRTUAL_TYPE (regnum
));
323 /* Convert raw data to virtual format if necessary. */
325 if (REGISTER_CONVERTIBLE (regnum
))
327 REGISTER_CONVERT_TO_VIRTUAL (regnum
, REGISTER_VIRTUAL_TYPE (regnum
),
328 raw_buffer
, VALUE_CONTENTS_RAW (reg_val
));
330 else if (REGISTER_RAW_SIZE (regnum
) == REGISTER_VIRTUAL_SIZE (regnum
))
331 memcpy (VALUE_CONTENTS_RAW (reg_val
), raw_buffer
,
332 REGISTER_RAW_SIZE (regnum
));
334 internal_error (__FILE__
, __LINE__
,
335 "Register \"%s\" (%d) has conflicting raw (%d) and virtual (%d) size",
336 REGISTER_NAME (regnum
),
338 REGISTER_RAW_SIZE (regnum
),
339 REGISTER_VIRTUAL_SIZE (regnum
));
340 VALUE_LVAL (reg_val
) = lval
;
341 VALUE_ADDRESS (reg_val
) = addr
;
342 VALUE_REGNO (reg_val
) = regnum
;
343 VALUE_OPTIMIZED_OUT (reg_val
) = optim
;
347 /* Given a pointer of type TYPE in target form in BUF, return the
348 address it represents. */
350 unsigned_pointer_to_address (struct type
*type
, void *buf
)
352 return extract_address (buf
, TYPE_LENGTH (type
));
356 signed_pointer_to_address (struct type
*type
, void *buf
)
358 return extract_signed_integer (buf
, TYPE_LENGTH (type
));
361 /* Given an address, store it as a pointer of type TYPE in target
364 unsigned_address_to_pointer (struct type
*type
, void *buf
, CORE_ADDR addr
)
366 store_address (buf
, TYPE_LENGTH (type
), addr
);
370 address_to_signed_pointer (struct type
*type
, void *buf
, CORE_ADDR addr
)
372 store_signed_integer (buf
, TYPE_LENGTH (type
), addr
);
375 /* Will calling read_var_value or locate_var_value on SYM end
376 up caring what frame it is being evaluated relative to? SYM must
379 symbol_read_needs_frame (struct symbol
*sym
)
381 switch (SYMBOL_CLASS (sym
))
383 /* All cases listed explicitly so that gcc -Wall will detect it if
384 we failed to consider one. */
389 case LOC_REGPARM_ADDR
:
393 case LOC_BASEREG_ARG
:
394 case LOC_THREAD_LOCAL_STATIC
:
404 /* Getting the address of a label can be done independently of the block,
405 even if some *uses* of that address wouldn't work so well without
409 case LOC_CONST_BYTES
:
411 case LOC_OPTIMIZED_OUT
:
417 /* Given a struct symbol for a variable,
418 and a stack frame id, read the value of the variable
419 and return a (pointer to a) struct value containing the value.
420 If the variable cannot be found, return a zero pointer.
421 If FRAME is NULL, use the selected_frame. */
424 read_var_value (register struct symbol
*var
, struct frame_info
*frame
)
426 register struct value
*v
;
427 struct type
*type
= SYMBOL_TYPE (var
);
431 v
= allocate_value (type
);
432 VALUE_LVAL (v
) = lval_memory
; /* The most likely possibility. */
433 VALUE_BFD_SECTION (v
) = SYMBOL_BFD_SECTION (var
);
435 len
= TYPE_LENGTH (type
);
438 frame
= selected_frame
;
440 switch (SYMBOL_CLASS (var
))
443 /* Put the constant back in target format. */
444 store_signed_integer (VALUE_CONTENTS_RAW (v
), len
,
445 (LONGEST
) SYMBOL_VALUE (var
));
446 VALUE_LVAL (v
) = not_lval
;
450 /* Put the constant back in target format. */
451 if (overlay_debugging
)
454 = symbol_overlayed_address (SYMBOL_VALUE_ADDRESS (var
),
455 SYMBOL_BFD_SECTION (var
));
456 store_typed_address (VALUE_CONTENTS_RAW (v
), type
, addr
);
459 store_typed_address (VALUE_CONTENTS_RAW (v
), type
,
460 SYMBOL_VALUE_ADDRESS (var
));
461 VALUE_LVAL (v
) = not_lval
;
464 case LOC_CONST_BYTES
:
467 bytes_addr
= SYMBOL_VALUE_BYTES (var
);
468 memcpy (VALUE_CONTENTS_RAW (v
), bytes_addr
, len
);
469 VALUE_LVAL (v
) = not_lval
;
474 if (overlay_debugging
)
475 addr
= symbol_overlayed_address (SYMBOL_VALUE_ADDRESS (var
),
476 SYMBOL_BFD_SECTION (var
));
478 addr
= SYMBOL_VALUE_ADDRESS (var
);
483 /* The import slot does not have a real address in it from the
484 dynamic loader (dld.sl on HP-UX), if the target hasn't
485 begun execution yet, so check for that. */
488 if (!target_has_execution
)
490 Attempt to access variable defined in different shared object or load module when\n\
491 addresses have not been bound by the dynamic loader. Try again when executable is running.");
493 locaddr
= SYMBOL_VALUE_ADDRESS (var
);
494 loc
= value_at (lookup_pointer_type (type
), locaddr
, NULL
);
495 addr
= value_as_address (loc
);
501 addr
= FRAME_ARGS_ADDRESS (frame
);
504 addr
+= SYMBOL_VALUE (var
);
513 argref
= FRAME_ARGS_ADDRESS (frame
);
516 argref
+= SYMBOL_VALUE (var
);
517 ref
= value_at (lookup_pointer_type (type
), argref
, NULL
);
518 addr
= value_as_address (ref
);
526 addr
= FRAME_LOCALS_ADDRESS (frame
);
527 addr
+= SYMBOL_VALUE (var
);
531 case LOC_BASEREG_ARG
:
532 case LOC_THREAD_LOCAL_STATIC
:
534 struct value
*regval
;
536 regval
= value_from_register (lookup_pointer_type (type
),
537 SYMBOL_BASEREG (var
), frame
);
539 error ("Value of base register not available.");
540 addr
= value_as_address (regval
);
541 addr
+= SYMBOL_VALUE (var
);
546 error ("Cannot look up value of a typedef");
550 if (overlay_debugging
)
551 VALUE_ADDRESS (v
) = symbol_overlayed_address
552 (BLOCK_START (SYMBOL_BLOCK_VALUE (var
)), SYMBOL_BFD_SECTION (var
));
554 VALUE_ADDRESS (v
) = BLOCK_START (SYMBOL_BLOCK_VALUE (var
));
559 case LOC_REGPARM_ADDR
:
562 int regno
= SYMBOL_VALUE (var
);
563 struct value
*regval
;
567 b
= get_frame_block (frame
, 0);
569 if (SYMBOL_CLASS (var
) == LOC_REGPARM_ADDR
)
571 regval
= value_from_register (lookup_pointer_type (type
),
576 error ("Value of register variable not available.");
578 addr
= value_as_address (regval
);
579 VALUE_LVAL (v
) = lval_memory
;
583 regval
= value_from_register (type
, regno
, frame
);
586 error ("Value of register variable not available.");
594 struct minimal_symbol
*msym
;
596 msym
= lookup_minimal_symbol (SYMBOL_NAME (var
), NULL
, NULL
);
599 if (overlay_debugging
)
600 addr
= symbol_overlayed_address (SYMBOL_VALUE_ADDRESS (msym
),
601 SYMBOL_BFD_SECTION (msym
));
603 addr
= SYMBOL_VALUE_ADDRESS (msym
);
607 case LOC_OPTIMIZED_OUT
:
608 VALUE_LVAL (v
) = not_lval
;
609 VALUE_OPTIMIZED_OUT (v
) = 1;
613 error ("Cannot look up value of a botched symbol.");
617 VALUE_ADDRESS (v
) = addr
;
622 /* Return a value of type TYPE, stored in register REGNUM, in frame
625 NOTE: returns NULL if register value is not available.
626 Caller will check return value or die! */
629 value_from_register (struct type
*type
, int regnum
, struct frame_info
*frame
)
631 char *raw_buffer
= (char*) alloca (MAX_REGISTER_RAW_SIZE
);
634 struct value
*v
= allocate_value (type
);
635 char *value_bytes
= 0;
636 int value_bytes_copied
= 0;
637 int num_storage_locs
;
641 CHECK_TYPEDEF (type
);
642 len
= TYPE_LENGTH (type
);
644 VALUE_REGNO (v
) = regnum
;
646 num_storage_locs
= (len
> REGISTER_VIRTUAL_SIZE (regnum
) ?
647 ((len
- 1) / REGISTER_RAW_SIZE (regnum
)) + 1 :
650 if (num_storage_locs
> 1
651 #ifdef GDB_TARGET_IS_H8500
652 || TYPE_CODE (type
) == TYPE_CODE_PTR
656 /* Value spread across multiple storage locations. */
659 int mem_stor
= 0, reg_stor
= 0;
660 int mem_tracking
= 1;
661 CORE_ADDR last_addr
= 0;
662 CORE_ADDR first_addr
= 0;
664 value_bytes
= (char *) alloca (len
+ MAX_REGISTER_RAW_SIZE
);
666 /* Copy all of the data out, whereever it may be. */
668 #ifdef GDB_TARGET_IS_H8500
669 /* This piece of hideosity is required because the H8500 treats registers
670 differently depending upon whether they are used as pointers or not. As a
671 pointer, a register needs to have a page register tacked onto the front.
672 An alternate way to do this would be to have gcc output different register
673 numbers for the pointer & non-pointer form of the register. But, it
674 doesn't, so we're stuck with this. */
676 if (TYPE_CODE (type
) == TYPE_CODE_PTR
687 page_regnum
= SEG_D_REGNUM
;
691 page_regnum
= SEG_E_REGNUM
;
695 page_regnum
= SEG_T_REGNUM
;
700 get_saved_register (value_bytes
+ 1,
707 if (register_cached (page_regnum
) == -1)
708 return NULL
; /* register value not available */
710 if (lval
== lval_register
)
717 get_saved_register (value_bytes
+ 2,
724 if (register_cached (regnum
) == -1)
725 return NULL
; /* register value not available */
727 if (lval
== lval_register
)
732 mem_tracking
= mem_tracking
&& (addr
== last_addr
);
737 #endif /* GDB_TARGET_IS_H8500 */
738 for (local_regnum
= regnum
;
739 value_bytes_copied
< len
;
740 (value_bytes_copied
+= REGISTER_RAW_SIZE (local_regnum
),
743 get_saved_register (value_bytes
+ value_bytes_copied
,
750 if (register_cached (local_regnum
) == -1)
751 return NULL
; /* register value not available */
753 if (regnum
== local_regnum
)
755 if (lval
== lval_register
)
763 && (regnum
== local_regnum
764 || addr
== last_addr
));
769 if ((reg_stor
&& mem_stor
)
770 || (mem_stor
&& !mem_tracking
))
771 /* Mixed storage; all of the hassle we just went through was
772 for some good purpose. */
774 VALUE_LVAL (v
) = lval_reg_frame_relative
;
775 VALUE_FRAME (v
) = FRAME_FP (frame
);
776 VALUE_FRAME_REGNUM (v
) = regnum
;
780 VALUE_LVAL (v
) = lval_memory
;
781 VALUE_ADDRESS (v
) = first_addr
;
785 VALUE_LVAL (v
) = lval_register
;
786 VALUE_ADDRESS (v
) = first_addr
;
789 internal_error (__FILE__
, __LINE__
,
790 "value_from_register: Value not stored anywhere!");
792 VALUE_OPTIMIZED_OUT (v
) = optim
;
794 /* Any structure stored in more than one register will always be
795 an integral number of registers. Otherwise, you'd need to do
796 some fiddling with the last register copied here for little
799 /* Copy into the contents section of the value. */
800 memcpy (VALUE_CONTENTS_RAW (v
), value_bytes
, len
);
802 /* Finally do any conversion necessary when extracting this
803 type from more than one register. */
804 #ifdef REGISTER_CONVERT_TO_TYPE
805 REGISTER_CONVERT_TO_TYPE (regnum
, type
, VALUE_CONTENTS_RAW (v
));
810 /* Data is completely contained within a single register. Locate the
811 register's contents in a real register or in core;
812 read the data in raw format. */
814 get_saved_register (raw_buffer
, &optim
, &addr
, frame
, regnum
, &lval
);
816 if (register_cached (regnum
) == -1)
817 return NULL
; /* register value not available */
819 VALUE_OPTIMIZED_OUT (v
) = optim
;
820 VALUE_LVAL (v
) = lval
;
821 VALUE_ADDRESS (v
) = addr
;
823 /* Convert the raw register to the corresponding data value's memory
824 format, if necessary. */
826 if (CONVERT_REGISTER_P (regnum
))
828 REGISTER_TO_VALUE (regnum
, type
, raw_buffer
, VALUE_CONTENTS_RAW (v
));
832 /* Raw and virtual formats are the same for this register. */
834 if (TARGET_BYTE_ORDER
== BFD_ENDIAN_BIG
&& len
< REGISTER_RAW_SIZE (regnum
))
836 /* Big-endian, and we want less than full size. */
837 VALUE_OFFSET (v
) = REGISTER_RAW_SIZE (regnum
) - len
;
840 memcpy (VALUE_CONTENTS_RAW (v
), raw_buffer
+ VALUE_OFFSET (v
), len
);
846 /* Given a struct symbol for a variable or function,
847 and a stack frame id,
848 return a (pointer to a) struct value containing the properly typed
852 locate_var_value (register struct symbol
*var
, struct frame_info
*frame
)
855 struct type
*type
= SYMBOL_TYPE (var
);
856 struct value
*lazy_value
;
858 /* Evaluate it first; if the result is a memory address, we're fine.
859 Lazy evaluation pays off here. */
861 lazy_value
= read_var_value (var
, frame
);
863 error ("Address of \"%s\" is unknown.", SYMBOL_SOURCE_NAME (var
));
865 if (VALUE_LAZY (lazy_value
)
866 || TYPE_CODE (type
) == TYPE_CODE_FUNC
)
870 addr
= VALUE_ADDRESS (lazy_value
);
871 val
= value_from_pointer (lookup_pointer_type (type
), addr
);
872 VALUE_BFD_SECTION (val
) = VALUE_BFD_SECTION (lazy_value
);
876 /* Not a memory address; check what the problem was. */
877 switch (VALUE_LVAL (lazy_value
))
880 gdb_assert (REGISTER_NAME (VALUE_REGNO (lazy_value
)) != NULL
881 && *REGISTER_NAME (VALUE_REGNO (lazy_value
)) != '\0');
882 error("Address requested for identifier "
883 "\"%s\" which is in register $%s",
884 SYMBOL_SOURCE_NAME (var
),
885 REGISTER_NAME (VALUE_REGNO (lazy_value
)));
888 case lval_reg_frame_relative
:
889 gdb_assert (REGISTER_NAME (VALUE_FRAME_REGNUM (lazy_value
)) != NULL
890 && *REGISTER_NAME (VALUE_FRAME_REGNUM (lazy_value
)) != '\0');
891 error("Address requested for identifier "
892 "\"%s\" which is in frame register $%s",
893 SYMBOL_SOURCE_NAME (var
),
894 REGISTER_NAME (VALUE_FRAME_REGNUM (lazy_value
)));
898 error ("Can't take address of \"%s\" which isn't an lvalue.",
899 SYMBOL_SOURCE_NAME (var
));
902 return 0; /* For lint -- never reached */
This page took 0.047273 seconds and 4 git commands to generate.