return val;
}
+/* Helper function for value_at, value_at_lazy, and value_at_lazy_stack. */
+
+static struct value *
+get_value_at (struct type *type, CORE_ADDR addr, int lazy)
+{
+ struct value *val;
+
+ if (TYPE_CODE (check_typedef (type)) == TYPE_CODE_VOID)
+ error (_("Attempt to dereference a generic pointer."));
+
+ if (lazy)
+ {
+ val = allocate_value_lazy (type);
+ }
+ else
+ {
+ val = allocate_value (type);
+ read_memory (addr, value_contents_all_raw (val), TYPE_LENGTH (type));
+ }
+
+ VALUE_LVAL (val) = lval_memory;
+ set_value_address (val, addr);
+
+ return val;
+}
+
/* Return a value with type TYPE located at ADDR.
Call value_at only if the data needs to be fetched immediately;
struct value *
value_at (struct type *type, CORE_ADDR addr)
{
- struct value *val;
-
- if (TYPE_CODE (check_typedef (type)) == TYPE_CODE_VOID)
- error (_("Attempt to dereference a generic pointer."));
-
- val = allocate_value (type);
-
- read_memory (addr, value_contents_all_raw (val), TYPE_LENGTH (type));
-
- VALUE_LVAL (val) = lval_memory;
- set_value_address (val, addr);
-
- return val;
+ return get_value_at (type, addr, 0);
}
/* Return a lazy value with type TYPE located at ADDR (cf. value_at). */
struct value *
value_at_lazy (struct type *type, CORE_ADDR addr)
{
- struct value *val;
-
- if (TYPE_CODE (check_typedef (type)) == TYPE_CODE_VOID)
- error (_("Attempt to dereference a generic pointer."));
-
- val = allocate_value_lazy (type);
-
- VALUE_LVAL (val) = lval_memory;
- set_value_address (val, addr);
-
- return val;
+ return get_value_at (type, addr, 1);
}
/* Called only from the value_contents and value_contents_all()
{
gdb_assert (value_lazy (val));
allocate_value_contents (val);
- if (VALUE_LVAL (val) == lval_memory)
+ if (value_bitsize (val))
+ {
+ /* To read a lazy bitfield, read the entire enclosing value. This
+ prevents reading the same block of (possibly volatile) memory once
+ per bitfield. It would be even better to read only the containing
+ word, but we have no way to record that just specific bits of a
+ value have been fetched. */
+ struct type *type = check_typedef (value_type (val));
+ enum bfd_endian byte_order = gdbarch_byte_order (get_type_arch (type));
+ struct value *parent = value_parent (val);
+ LONGEST offset = value_offset (val);
+ LONGEST num = unpack_bits_as_long (value_type (val),
+ value_contents (parent) + offset,
+ value_bitpos (val),
+ value_bitsize (val));
+ int length = TYPE_LENGTH (type);
+ store_signed_integer (value_contents_raw (val), length, byte_order, num);
+ }
+ else if (VALUE_LVAL (val) == lval_memory)
{
CORE_ADDR addr = value_address (val);
int length = TYPE_LENGTH (check_typedef (value_enclosing_type (val)));
if (length)
- read_memory (addr, value_contents_all_raw (val), length);
+ {
+ if (value_stack (val))
+ read_stack (addr, value_contents_all_raw (val), length);
+ else
+ read_memory (addr, value_contents_all_raw (val), length);
+ }
}
else if (VALUE_LVAL (val) == lval_register)
{
if (value_bitsize (toval))
{
- /* We assume that the argument to read_memory is in units
- of host chars. FIXME: Is that correct? */
+ struct value *parent = value_parent (toval);
+ changed_addr = value_address (parent) + value_offset (toval);
+
changed_len = (value_bitpos (toval)
+ value_bitsize (toval)
+ HOST_CHAR_BIT - 1)
/ HOST_CHAR_BIT;
+ /* If we can read-modify-write exactly the size of the
+ containing type (e.g. short or int) then do so. This
+ is safer for volatile bitfields mapped to hardware
+ registers. */
+ if (changed_len < TYPE_LENGTH (type)
+ && TYPE_LENGTH (type) <= (int) sizeof (LONGEST)
+ && ((LONGEST) changed_addr % TYPE_LENGTH (type)) == 0)
+ changed_len = TYPE_LENGTH (type);
+
if (changed_len > (int) sizeof (LONGEST))
error (_("Can't handle bitfields which don't fit in a %d bit word."),
(int) sizeof (LONGEST) * HOST_CHAR_BIT);
- read_memory (value_address (toval), buffer, changed_len);
+ read_memory (changed_addr, buffer, changed_len);
modify_field (type, buffer, value_as_long (fromval),
value_bitpos (toval), value_bitsize (toval));
- changed_addr = value_address (toval);
dest_buffer = buffer;
}
else
{
if (value_bitsize (toval))
{
+ struct value *parent = value_parent (toval);
+ int offset = value_offset (parent) + value_offset (toval);
int changed_len;
gdb_byte buffer[sizeof (LONGEST)];
error (_("Can't handle bitfields which don't fit in a %d bit word."),
(int) sizeof (LONGEST) * HOST_CHAR_BIT);
- get_frame_register_bytes (frame, value_reg,
- value_offset (toval),
+ get_frame_register_bytes (frame, value_reg, offset,
changed_len, buffer);
modify_field (type, buffer, value_as_long (fromval),
value_bitpos (toval), value_bitsize (toval));
- put_frame_register_bytes (frame, value_reg,
- value_offset (toval),
+ put_frame_register_bytes (frame, value_reg, offset,
changed_len, buffer);
}
else