* This code is derived from software copyrighted by the Free Software
* Modified 1991 by Donn Seeley at UUNET Technologies, Inc.
* Modified 1990 by Van Jacobson at Lawrence Berkeley Laboratory.
static char sccsid
[] = "@(#)values.c 6.3 (Berkeley) 5/8/91";
/* Low level packing and unpacking of values for GDB.
Copyright (C) 1986, 1987, 1989 Free Software Foundation, Inc.
This file is part of GDB.
GDB is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 1, or (at your option)
GDB is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with GDB; see the file COPYING. If not, write to
the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */
/* The value-history records all the values printed
by print commands during this session. Each chunk
records 60 consecutive values. The first chunk on
the chain records the most recent values.
The total number of values is in value_history_count. */
#define VALUE_HISTORY_CHUNK 60
struct value_history_chunk
struct value_history_chunk
*next
;
value values
[VALUE_HISTORY_CHUNK
];
/* Chain of chunks now in use. */
static struct value_history_chunk
*value_history_chain
;
static int value_history_count
; /* Abs number of last entry stored */
/* List of all value objects currently allocated
(except for those released by calls to release_value)
This is so they can be freed after each command. */
/* Allocate a value that has the correct length for type TYPE. */
/* If the type we want had no definition in the file it first
* appeared in, it will be marked a `stub'. The real definition
* probably appeared later so try to find it. */
if (TYPE_FLAGS(type
) & TYPE_FLAG_STUB
)
register struct symbol
*sym
;
if (cp
= index(TYPE_NAME(type
), ' '))
sym
= lookup_symbol(cp
, 0, STRUCT_NAMESPACE
, 0);
if (sym
&& TYPE_CODE(SYMBOL_TYPE(sym
)) == TYPE_CODE(type
))
bcopy (SYMBOL_TYPE (sym
), type
, sizeof (*type
));
val
= (value
) xmalloc (sizeof (struct value
) + TYPE_LENGTH (type
));
VALUE_NEXT (val
) = all_values
;
VALUE_LVAL (val
) = not_lval
;
VALUE_REPEATED (val
) = 0;
VALUE_REPETITIONS (val
) = 0;
/* Allocate a value that has the correct length
for COUNT repetitions type TYPE. */
allocate_repeat_value (type
, count
)
val
= (value
) xmalloc (sizeof (struct value
) + TYPE_LENGTH (type
) * count
);
VALUE_NEXT (val
) = all_values
;
VALUE_LVAL (val
) = not_lval
;
VALUE_REPEATED (val
) = 1;
VALUE_REPETITIONS (val
) = count
;
/* Free all the values that have been allocated (except for those released).
Called after each command, successful or not. */
register value val
, next
;
for (val
= all_values
; val
; val
= next
)
/* Remove VAL from the chain all_values
so it will not be freed automatically. */
for (v
= all_values
; v
; v
= v
->next
)
/* Return a copy of the value ARG.
It contains the same contents, for same memory address,
but it's a different block of storage. */
register struct type
*type
= VALUE_TYPE (arg
);
if (VALUE_REPEATED (arg
))
val
= allocate_repeat_value (type
, VALUE_REPETITIONS (arg
));
val
= allocate_value (type
);
VALUE_LVAL (val
) = VALUE_LVAL (arg
);
VALUE_ADDRESS (val
) = VALUE_ADDRESS (arg
);
VALUE_OFFSET (val
) = VALUE_OFFSET (arg
);
VALUE_BITPOS (val
) = VALUE_BITPOS (arg
);
VALUE_BITSIZE (val
) = VALUE_BITSIZE (arg
);
VALUE_REGNO (val
) = VALUE_REGNO (arg
);
bcopy (VALUE_CONTENTS (arg
), VALUE_CONTENTS (val
),
TYPE_LENGTH (VALUE_TYPE (arg
))
* (VALUE_REPEATED (arg
) ? VALUE_REPETITIONS (arg
) : 1));
/* Access to the value history. */
/* Record a new value in the value history.
Returns the absolute history index of the entry. */
record_latest_value (val
)
/* Check error now if about to store an invalid float. We return -1
to the caller, but allow them to continue, e.g. to print it as "Nan". */
if (TYPE_CODE (VALUE_TYPE (val
)) == TYPE_CODE_FLT
) {
foo
= unpack_double (VALUE_TYPE (val
), VALUE_CONTENTS (val
), &i
);
if (i
) return -1; /* Indicate value not saved in history */
/* Here we treat value_history_count as origin-zero
and applying to the value being stored now. */
i
= value_history_count
% VALUE_HISTORY_CHUNK
;
register struct value_history_chunk
*new
= (struct value_history_chunk
*)
xmalloc (sizeof (struct value_history_chunk
));
bzero (new->values
, sizeof new->values
);
new->next
= value_history_chain
;
value_history_chain
= new;
value_history_chain
->values
[i
] = val
;
/* Now we regard value_history_count as origin-one
and applying to the value just stored. */
return ++value_history_count
;
/* Return a copy of the value in the history with sequence number NUM. */
access_value_history (num
)
register struct value_history_chunk
*chunk
;
register int absnum
= num
;
absnum
+= value_history_count
;
error ("The history is empty.");
error ("There is only one value in the history.");
error ("History does not go back to $$%d.", -num
);
if (absnum
> value_history_count
)
error ("History has not yet reached $%d.", absnum
);
/* Now absnum is always absolute and origin zero. */
chunk
= value_history_chain
;
for (i
= (value_history_count
- 1) / VALUE_HISTORY_CHUNK
- absnum
/ VALUE_HISTORY_CHUNK
;
return value_copy (chunk
->values
[absnum
% VALUE_HISTORY_CHUNK
]);
/* Clear the value history entirely.
Must be done when new symbol tables are loaded,
because the type pointers become invalid. */
register struct value_history_chunk
*next
;
while (value_history_chain
)
for (i
= 0; i
< VALUE_HISTORY_CHUNK
; i
++)
if (val
= value_history_chain
->values
[i
])
next
= value_history_chain
->next
;
free (value_history_chain
);
value_history_chain
= next
;
value_history_info (num_exp
, from_tty
)
if (num_exp
[0] == '+' && num_exp
[1] == '\0')
/* "info history +" should print from the stored position. */
/* "info history <exp>" should print around value number <exp>. */
num
= parse_and_eval_address (num_exp
) - 5;
/* "info history" means print the last 10 values. */
num
= value_history_count
- 9;
for (i
= num
; i
< num
+ 10 && i
<= value_history_count
; i
++)
val
= access_value_history (i
);
printf_filtered ("$%d = ", i
);
value_print (val
, stdout
, 0, Val_pretty_default
);
/* The next "info history +" should start after what we just printed. */
/* Hitting just return after this command should do the same thing as
"info history +". If num_exp is null, this is unnecessary, since
"info history +" is not useful after "info history". */
/* Internal variables. These are variables within the debugger
that hold values assigned by debugger commands.
The user refers to them with a '$' prefix
that does not appear in the variable names stored internally. */
static struct internalvar
*internalvars
;
/* Look up an internal variable with name NAME. NAME should not
normally include a dollar sign.
If the specified internal variable does not exist,
one is created, with a void value. */
lookup_internalvar (name
)
register struct internalvar
*var
;
for (var
= internalvars
; var
; var
= var
->next
)
if (!strcmp (var
->name
, name
))
var
= (struct internalvar
*) xmalloc (sizeof (struct internalvar
));
var
->name
= concat (name
, "", "");
var
->value
= allocate_value (builtin_type_void
);
release_value (var
->value
);
var
->next
= internalvars
;
value_of_internalvar (var
)
#ifdef IS_TRAPPED_INTERNALVAR
if (IS_TRAPPED_INTERNALVAR (var
->name
))
return VALUE_OF_TRAPPED_INTERNALVAR (var
);
val
= value_copy (var
->value
);
VALUE_LVAL (val
) = lval_internalvar
;
VALUE_INTERNALVAR (val
) = var
;
set_internalvar_component (var
, offset
, bitpos
, bitsize
, newval
)
int offset
, bitpos
, bitsize
;
register char *addr
= VALUE_CONTENTS (var
->value
) + offset
;
#ifdef IS_TRAPPED_INTERNALVAR
if (IS_TRAPPED_INTERNALVAR (var
->name
))
SET_TRAPPED_INTERNALVAR (var
, newval
, bitpos
, bitsize
, offset
);
modify_field (addr
, (int) value_as_long (newval
),
bcopy (VALUE_CONTENTS (newval
), addr
,
TYPE_LENGTH (VALUE_TYPE (newval
)));
set_internalvar (var
, val
)
#ifdef IS_TRAPPED_INTERNALVAR
if (IS_TRAPPED_INTERNALVAR (var
->name
))
SET_TRAPPED_INTERNALVAR (var
, val
, 0, 0, 0);
var
->value
= value_copy (val
);
release_value (var
->value
);
/* Free all internalvars. Done when new symtabs are loaded,
because that makes the values invalid. */
register struct internalvar
*var
;
internalvars
= var
->next
;
register struct internalvar
*var
;
for (var
= internalvars
; var
; var
= var
->next
)
#ifdef IS_TRAPPED_INTERNALVAR
if (IS_TRAPPED_INTERNALVAR (var
->name
))
printf ("Debugger convenience variables:\n\n");
printf ("$%s: ", var
->name
);
value_print (var
->value
, stdout
, 0, Val_pretty_default
);
printf ("No debugger convenience variables now defined.\n\
Convenience variables have names starting with \"$\";\n\
use \"set\" as in \"set $foo = 5\" to define them.\n");
/* Extract a value as a C number (either long or double).
Knows how to convert fixed values to double, or
Does not deallocate the value. */
return unpack_long (VALUE_TYPE (val
), VALUE_CONTENTS (val
));
foo
= unpack_double (VALUE_TYPE (val
), VALUE_CONTENTS (val
), &inv
);
error ("Invalid floating value found in program.");
/* Unpack raw data (copied from debugee) at VALADDR
as a long, or as a double, assuming the raw data is described
by type TYPE. Knows how to convert different sizes of values
and can convert between fixed and floating point.
C++: It is assumed that the front-end has taken care of
all matters concerning pointers to members. A pointer
to member which reaches here is considered to be equivalent
to an INT (or some size). After all, it is only an offset. */
unpack_long (type
, valaddr
)
register enum type_code code
= TYPE_CODE (type
);
register int len
= TYPE_LENGTH (type
);
register int nosign
= TYPE_UNSIGNED (type
);
if (code
== TYPE_CODE_ENUM
)
if (code
== TYPE_CODE_FLT
)
if (len
== sizeof (float))
return * (float *) valaddr
;
if (len
== sizeof (double))
return * (double *) valaddr
;
else if (code
== TYPE_CODE_INT
&& nosign
)
if (len
== sizeof (char))
return * (unsigned char *) valaddr
;
if (len
== sizeof (short))
return * (unsigned short *) valaddr
;
return * (unsigned int *) valaddr
;
if (len
== sizeof (long))
return * (unsigned long *) valaddr
;
if (len
== sizeof (long long))
return * (unsigned long long *) valaddr
;
else if (code
== TYPE_CODE_INT
)
if (len
== sizeof (char))
return * (char *) valaddr
;
if (len
== sizeof (short))
return * (short *) valaddr
;
return * (int *) valaddr
;
if (len
== sizeof (long))
return * (long *) valaddr
;
if (len
== sizeof (long long))
return * (long long *) valaddr
;
else if (code
== TYPE_CODE_PTR
|| code
== TYPE_CODE_REF
)
if (len
== sizeof (char *))
return (CORE_ADDR
) * (char **) valaddr
;
else if (code
== TYPE_CODE_MEMBER
)
error ("not implemented: member types in unpack_long");
error ("Value not integer or pointer.");
/* Return a double value from the specified type and address.
INVP points to an int which is set to 0 for valid value,
1 for invalid value (bad float format). In either case,
the returned double is OK to use. */
unpack_double (type
, valaddr
, invp
)
register enum type_code code
= TYPE_CODE (type
);
register int len
= TYPE_LENGTH (type
);
register int nosign
= TYPE_UNSIGNED (type
);
*invp
= 0; /* Assume valid. */
if (code
== TYPE_CODE_FLT
)
if (INVALID_FLOAT (valaddr
, len
))
return 1.234567891011121314;
if (len
== sizeof (float))
return * (float *) valaddr
;
if (len
== sizeof (double))
/* Some machines require doubleword alignment for doubles.
This code works on them, and on other machines. */
bcopy ((char *) valaddr
, (char *) &temp
, sizeof (double));
else if (code
== TYPE_CODE_INT
&& nosign
)
if (len
== sizeof (char))
return * (unsigned char *) valaddr
;
if (len
== sizeof (short))
return * (unsigned short *) valaddr
;
return * (unsigned int *) valaddr
;
if (len
== sizeof (long))
return * (unsigned long *) valaddr
;
if (len
== sizeof (long long))
return * (unsigned long long *) valaddr
;
else if (code
== TYPE_CODE_INT
)
if (len
== sizeof (char))
return * (char *) valaddr
;
if (len
== sizeof (short))
return * (short *) valaddr
;
return * (int *) valaddr
;
if (len
== sizeof (long))
return * (long *) valaddr
;
if (len
== sizeof (long long))
return * (long long *) valaddr
;
error ("Value not floating number.");
return (double) 0; /* To silence compiler warning. */
/* Given a value ARG1 of a struct or union type,
extract and return the value of one of its fields.
FIELDNO says which field.
For C++, must also be able to return values from static fields */
value_field (arg1
, fieldno
)
register struct type
*type
= TYPE_FIELD_TYPE (VALUE_TYPE (arg1
), fieldno
);
/* Handle packed fields */
offset
= TYPE_FIELD_BITPOS (VALUE_TYPE (arg1
), fieldno
) / 8;
if (TYPE_FIELD_BITSIZE (VALUE_TYPE (arg1
), fieldno
))
v
= value_from_long (type
,
unpack_field_as_long (VALUE_TYPE (arg1
),
VALUE_BITPOS (v
) = TYPE_FIELD_BITPOS (VALUE_TYPE (arg1
), fieldno
) % 8;
VALUE_BITSIZE (v
) = TYPE_FIELD_BITSIZE (VALUE_TYPE (arg1
), fieldno
);
v
= allocate_value (type
);
bcopy (VALUE_CONTENTS (arg1
) + offset
,
VALUE_LVAL (v
) = VALUE_LVAL (arg1
);
if (VALUE_LVAL (arg1
) == lval_internalvar
)
VALUE_LVAL (v
) = lval_internalvar_component
;
VALUE_ADDRESS (v
) = VALUE_ADDRESS (arg1
);
VALUE_OFFSET (v
) = offset
+ VALUE_OFFSET (arg1
);
value_fn_field (arg1
, fieldno
, subfieldno
)
struct fn_field
*f
= TYPE_FN_FIELDLIST1 (VALUE_TYPE (arg1
), fieldno
);
register struct type
*type
= TYPE_FN_FIELD_TYPE (f
, subfieldno
);
sym
= lookup_symbol (TYPE_FN_FIELD_PHYSNAME (f
, subfieldno
),
if (! sym
) error ("Internal error: could not find physical method named %s",
TYPE_FN_FIELD_PHYSNAME (f
, subfieldno
));
v
= allocate_value (type
);
VALUE_ADDRESS (v
) = BLOCK_START (SYMBOL_BLOCK_VALUE (sym
));
/* Return a virtual function as a value.
ARG1 is the object which provides the virtual function
F is the list of member functions which contains the desired virtual
J is an index into F which provides the desired virtual function.
TYPE is the basetype which first provides the virtual function table. */
value_virtual_fn_field (arg1
, f
, j
, type
)
/* First, get the virtual function table pointer. That comes
with a strange type, so cast it to type `pointer to long' (which
should serve just fine as a function type). Then, index into
the table, and convert final value to appropriate function type. */
value vi
= value_from_long (builtin_type_int
,
(LONGEST
) TYPE_FN_FIELD_VOFFSET (f
, j
));
VALUE_TYPE (arg1
) = TYPE_VPTR_BASETYPE (type
);
/* This type may have been defined before its virtual function table
was. If so, fill in the virtual function table entry for the
if (TYPE_VPTR_FIELDNO (type
) < 0)
= fill_in_vptr_fieldno (type
);
/* The virtual function table is now an array of structures
which have the form { int16 offset, delta; void *pfn; }. */
vtbl
= value_ind (value_field (arg1
, TYPE_VPTR_FIELDNO (type
)));
/* Index into the virtual function table. This is hard-coded because
looking up a field is not cheap, and it may be important to save
time, e.g. if the user has set a conditional breakpoint calling
vfn
= value_field (value_subscript (vtbl
, vi
), 2);
/* Reinstantiate the function pointer with the correct type. */
VALUE_TYPE (vfn
) = lookup_pointer_type (TYPE_FN_FIELD_TYPE (f
, j
));
/* The value of a static class member does not depend
on its instance, only on its type. If FIELDNO >= 0,
then fieldno is a valid field number and is used directly.
Otherwise, FIELDNAME is the name of the field we are
searching for. If it is not a static field name, an
error is signaled. TYPE is the type in which we look for the
value_static_field (type
, fieldname
, fieldno
)
register struct type
*type
;
register struct type
*t
= type
;
/* Look for static field. */
for (i
= TYPE_NFIELDS (t
) - 1; i
>= 0; i
--)
if (! strcmp (TYPE_FIELD_NAME (t
, i
), fieldname
))
if (TYPE_FIELD_STATIC (t
, i
))
error ("field `%s' is not static");
t
= TYPE_BASECLASSES (t
) ? TYPE_BASECLASS (t
, 1) : 0;
if (destructor_name_p (fieldname
, t
))
error ("use `info method' command to print out value of destructor");
for (i
= TYPE_NFN_FIELDS (t
) - 1; i
>= 0; i
--)
if (! strcmp (TYPE_FN_FIELDLIST_NAME (t
, i
), fieldname
))
error ("use `info method' command to print value of method \"%s\"", fieldname
);
t
= TYPE_BASECLASSES (t
) ? TYPE_BASECLASS (t
, 1) : 0;
error("there is no field named %s", fieldname
);
sym
= lookup_symbol (TYPE_FIELD_STATIC_PHYSNAME (type
, fieldno
),
if (! sym
) error ("Internal error: could not find physical static variable named %s", TYPE_FIELD_BITSIZE (type
, fieldno
));
type
= TYPE_FIELD_TYPE (type
, fieldno
);
v
= value_at (type
, (CORE_ADDR
)SYMBOL_BLOCK_VALUE (sym
));
unpack_field_as_long (type
, valaddr
, fieldno
)
int bitpos
= TYPE_FIELD_BITPOS (type
, fieldno
);
int bitsize
= TYPE_FIELD_BITSIZE (type
, fieldno
);
bcopy (valaddr
+ bitpos
/ 8, &val
, sizeof val
);
/* Extracting bits depends on endianness of the machine. */
val
= val
>> (sizeof val
* 8 - bitpos
% 8 - bitsize
);
val
= val
>> (bitpos
% 8);
val
&= (1 << bitsize
) - 1;
modify_field (addr
, fieldval
, bitpos
, bitsize
)
/* Reject values too big to fit in the field in question.
Otherwise adjoining fields may be corrupted. */
if (fieldval
& ~((1<<bitsize
)-1))
error ("Value %d does not fit in %d bits.", fieldval
, bitsize
);
bcopy (addr
, &oword
, sizeof oword
);
/* Shifting for bit field depends on endianness of the machine. */
bitpos
= sizeof (oword
) * 8 - bitpos
- bitsize
;
oword
&= ~(((1 << bitsize
) - 1) << bitpos
);
oword
|= fieldval
<< bitpos
;
bcopy (&oword
, addr
, sizeof oword
);
/* Convert C numbers into newly allocated values */
value_from_long (type
, num
)
register value val
= allocate_value (type
);
register enum type_code code
= TYPE_CODE (type
);
register int len
= TYPE_LENGTH (type
);
if (code
== TYPE_CODE_INT
|| code
== TYPE_CODE_ENUM
)
if (len
== sizeof (char))
* (char *) VALUE_CONTENTS (val
) = num
;
else if (len
== sizeof (short))
* (short *) VALUE_CONTENTS (val
) = num
;
else if (len
== sizeof (int))
* (int *) VALUE_CONTENTS (val
) = num
;
else if (len
== sizeof (long))
* (long *) VALUE_CONTENTS (val
) = num
;
else if (len
== sizeof (long long))
* (long long *) VALUE_CONTENTS (val
) = num
;
error ("Integer type encountered with unexpected data length.");
error ("Unexpected type encountered for integer constant.");
value_from_double (type
, num
)
register value val
= allocate_value (type
);
register enum type_code code
= TYPE_CODE (type
);
register int len
= TYPE_LENGTH (type
);
if (code
== TYPE_CODE_FLT
)
if (len
== sizeof (float))
* (float *) VALUE_CONTENTS (val
) = num
;
else if (len
== sizeof (double))
* (double *) VALUE_CONTENTS (val
) = num
;
error ("Floating type encountered with unexpected data length.");
error ("Unexpected type encountered for floating constant.");
/* Deal with the value that is "about to be returned". */
/* Return the value that a function returning now
would be returning to its caller, assuming its type is VALTYPE.
RETBUF is where we look for what ought to be the contents
of the registers (in raw form). This is because it is often
desirable to restore old values to those registers
after saving the contents of interest, and then call
this function using the saved values.
struct_return is non-zero when the function in question is
using the structure return conventions on the machine in question;
0 when it is using the value returning conventions (this often
means returning pointer to where structure is vs. returning value). */
value_being_returned (valtype
, retbuf
, struct_return
)
register struct type
*valtype
;
char retbuf
[REGISTER_BYTES
];
return value_at (valtype
, EXTRACT_STRUCT_VALUE_ADDRESS (retbuf
));
val
= allocate_value (valtype
);
EXTRACT_RETURN_VALUE (valtype
, retbuf
, VALUE_CONTENTS (val
));
/* Return true if the function specified is using the structure returning
convention on this machine to return arguments, or 0 if it is using
the value returning convention. FUNCTION is the value representing
the function, FUNCADDR is the address of the function, and VALUE_TYPE
is the type returned by the function */
struct block
*block_for_pc ();
using_struct_return (function
, funcaddr
, value_type
)
register enum type_code code
= TYPE_CODE (value_type
);
if (code
== TYPE_CODE_STRUCT
||
code
== TYPE_CODE_UNION
||
struct block
*b
= block_for_pc (funcaddr
);
if (!(BLOCK_GCC_COMPILED (b
) && TYPE_LENGTH (value_type
) < 8))
/* Store VAL so it will be returned if a function returns now.
Does not verify that VAL's type matches what the current
function wants to return. */
register enum type_code code
= TYPE_CODE (VALUE_TYPE (val
));
char regbuf
[REGISTER_BYTES
];
if (code
== TYPE_CODE_STRUCT
|| code
== TYPE_CODE_UNION
)
error ("Specifying a struct or union return value is not supported.");
if (code
== TYPE_CODE_FLT
)
dbuf
= value_as_double (val
);
STORE_RETURN_VALUE (VALUE_TYPE (val
), &dbuf
);
lbuf
= value_as_long (val
);
STORE_RETURN_VALUE (VALUE_TYPE (val
), &lbuf
);
add_info ("convenience", convenience_info
,
"Debugger convenience (\"$foo\") variables.\n\
These variables are created when you assign them values;\n\
thus, \"print $foo=1\" gives \"$foo\" the value 1. Values may be any type.\n\n\
A few convenience variables are given values automatically GDB:\n\
\"$_\"holds the last address examined with \"x\" or \"info lines\",\n\
\"$__\" holds the contents of the last address examined with \"x\".");
add_info ("values", value_history_info
,
"Elements of value history (around item number IDX, or last ten).");
add_info_alias ("history", value_history_info
, 0);