- When we store the entire object, `enclosing_type' is the run-time
- type -- the complete object -- and `embedded_offset' is the
- offset of `type' within that larger type, in bytes. The
- VALUE_CONTENTS macro takes `embedded_offset' into account, so
- most GDB code continues to see the `type' portion of the value,
- just as the inferior would.
-
- If `type' is a pointer to an object, then `enclosing_type' is a
- pointer to the object's run-time type, and `pointed_to_offset' is
- the offset in bytes from the full object to the pointed-to object
- -- that is, the value `embedded_offset' would have if we followed
- the pointer and fetched the complete object. (I don't really see
- the point. Why not just determine the run-time type when you
- indirect, and avoid the special case? The contents don't matter
- until you indirect anyway.)
-
- If we're not doing anything fancy, `enclosing_type' is equal to
- `type', and `embedded_offset' is zero, so everything works
- normally. */
- struct type *enclosing_type;
- int embedded_offset;
- int pointed_to_offset;
-
- /* Values are stored in a chain, so that they can be deleted easily
- over calls to the inferior. Values assigned to internal
- variables or put into the value history are taken off this
- list. */
- struct value *next;
-
- /* Register number if the value is from a register. */
- short regnum;
-
- /* If zero, contents of this value are in the contents field. If
- nonzero, contents are in inferior memory at address in the
- location.address field plus the offset field (and the lval field
- should be lval_memory).
-
- WARNING: This field is used by the code which handles watchpoints
- (see breakpoint.c) to decide whether a particular value can be
- watched by hardware watchpoints. If the lazy flag is set for
- some member of a value chain, it is assumed that this member of
- the chain doesn't need to be watched as part of watching the
- value itself. This is how GDB avoids watching the entire struct
- or array when the user wants to watch a single struct member or
- array element. If you ever change the way lazy flag is set and
- reset, be sure to consider this use as well! */
- char lazy;
-
- /* If nonzero, this is the value of a variable which does not
- actually exist in the program. */
- char optimized_out;
-
- /* Actual contents of the value. For use of this value; setting it
- uses the stuff above. Not valid if lazy is nonzero. Target
- byte-order. We force it to be aligned properly for any possible
- value. Note that a value therefore extends beyond what is
- declared here. */
- union
- {
- bfd_byte contents[1];
- DOUBLEST force_doublest_align;
- LONGEST force_longest_align;
- CORE_ADDR force_core_addr_align;
- void *force_pointer_align;
- } aligner;
- /* Do not add any new members here -- contents above will trash
- them. */
-};