replace frame implementation with VM frames

* libguile/stacks.h: Rework so that a stack doesn't copy information out
  of VM frames, it just holds onto a VM frame, along with the stack id
  and length. VM frames are now the only representation of frames in
  Guile.
  (scm_t_info_frame, SCM_FRAME_N_SLOTS, SCM_FRAME_REF, SCM_FRAME_NUMBER)
  (SCM_FRAME_FLAGS, SCM_FRAME_SOURCE, SCM_FRAME_PROC, SCM_FRAME_ARGS)
  (SCM_FRAME_PREV, SCM_FRAME_NEXT)
  (SCM_FRAMEF_VOID, SCM_FRAMEF_REAL, SCM_FRAMEF_PROC)
  (SCM_FRAMEF_EVAL_ARGS, SCM_FRAMEF_OVERFLOW)
  (SCM_FRAME_VOID_P, SCM_FRAME_REAL_P, SCM_FRAME_PROC_P)
  (SCM_FRAME_EVAL_ARGS_P, SCM_FRAME_OVERFLOW_P): Remove these macros
  corresponding to the old frame implementation.
  (scm_frame_p scm_frame_source, scm_frame_procedure)
  (scm_frame_arguments): These definitions are now in frames.h.
  (scm_last_stack_frame): Remove declaration of previously-removed
  constructor. Probably should re-instate it though.
  (scm_frame_number, scm_frame_previous, scm_frame_next)
  (scm_frame_real_p, scm_frame_procedure_p, scm_frame_evaluating_args_p)
  (scm_frame_overflow_p) : Remove these procedures corresponding to the
  old stack implementation.

* libguile/stacks.c: Update for new frames implementation.

* libguile/frames.h:
* libguile/frames.c: Rename functions operating on VM frames to have a
  scm_frame prefix, not scm_vm_frame -- because they really are the only
  frames we have. Rename corresponding Scheme functions too, from
  vm-frame-foo to frame-foo.

* libguile/deprecated.h: Remove scm_stack and scm_info_frame data types.

* libguile/vm.c (vm_dispatch_hook): Adapt to scm_c_make_frame name
  change.

* module/system/vm/frame.scm: No need to export functions provided
  frames.c now, as we load those procedures into the default environment
  now. Rename functions, and remove a couple of outdated, unused
  functions. The bottom half of this file is still bitrotten, though.

* libguile/backtrace.c: Rework to operate on the new frame
  representation. Also fix a bug displaying file names for compiled
  procedures.

* libguile/init.c: Load the VM much earlier, just because we can. Also
  it allows us to have frames.[ch] loaded in time for stacks to be
  initialized, so that scm_frame_arguments can do the right thing.

libguile/stacks.h

@@ -24,67 +24,28 @@
 
 
 #include "libguile/__scm.h"
+#include "libguile/frames.h"
 
 /* {Frames and stacks}
  */
 
-typedef struct scm_t_info_frame {
-  /* SCM flags; */
-  scm_t_bits flags;
-  SCM source;
-  SCM proc;
-  SCM args;
-} scm_t_info_frame;
-#define SCM_FRAME_N_SLOTS (sizeof (scm_t_info_frame) / sizeof (SCM))
-
-#define SCM_STACK(obj) ((scm_t_stack *) SCM_STRUCT_DATA (obj))
-#define SCM_STACK_LAYOUT "pwuourpW"
-typedef struct scm_t_stack {
-  SCM id;			/* Stack id */
-  scm_t_info_frame *frames;	/* Info frames */
-  unsigned long length;		/* Stack length */
-  unsigned long tail_length;
-  scm_t_info_frame tail[1];
-} scm_t_stack;
-
 SCM_API SCM scm_stack_type;
 
+#define SCM_STACK_LAYOUT                        \
+  "pw" /* len */                                \
+  "pw" /* id */                                 \
+  "pw" /* frame */
+
 #define SCM_STACKP(obj) (SCM_STRUCTP (obj) && scm_is_eq (SCM_STRUCT_VTABLE (obj), scm_stack_type))
-#define SCM_STACK_LENGTH(stack) (SCM_STACK (stack) -> length)
+#define SCM_STACK_LENGTH(obj) (scm_to_long (SCM_STRUCT_SLOT_REF (obj,0)))
+#define SCM_SET_STACK_LENGTH(obj,f) (SCM_STRUCT_SLOT_SET (obj,0,scm_from_long (f)))
+#define SCM_STACK_ID(obj) (SCM_STRUCT_SLOT_REF (obj,1))
+#define SCM_SET_STACK_ID(obj,f) (SCM_STRUCT_SLOT_SET (obj,1,f))
+#define SCM_STACK_FRAME(obj) (SCM_STRUCT_SLOT_REF (obj,2))
+#define SCM_SET_STACK_FRAME(obj,f) (SCM_STRUCT_SLOT_SET (obj,2,f))
 
-#define SCM_FRAMEP(obj) \
-  (scm_is_pair (obj) && SCM_STACKP (SCM_CAR (obj)) \
-   && scm_is_unsigned_integer (SCM_CDR (obj), \
-                               0, SCM_STACK_LENGTH (SCM_CAR (obj))-1))
+#define SCM_FRAMEP(obj) (SCM_VM_FRAME_P (obj))
 
-#define SCM_FRAME_REF(frame, slot) \
-(SCM_STACK (SCM_CAR (frame)) -> frames[scm_to_size_t (SCM_CDR (frame))].slot)
-
-#define SCM_FRAME_NUMBER(frame) \
-(SCM_BACKWARDS_P \
- ? scm_to_size_t (SCM_CDR (frame)) \
- : (SCM_STACK_LENGTH (SCM_CAR (frame)) \
-    - scm_to_size_t (SCM_CDR (frame)) \
-    - 1)) \
-
-#define SCM_FRAME_FLAGS(frame) SCM_FRAME_REF (frame, flags)
-#define SCM_FRAME_SOURCE(frame) SCM_FRAME_REF (frame, source)
-#define SCM_FRAME_PROC(frame) SCM_FRAME_REF (frame, proc)
-#define SCM_FRAME_ARGS(frame) SCM_FRAME_REF (frame, args)
-#define SCM_FRAME_PREV(frame) scm_frame_previous (frame)
-#define SCM_FRAME_NEXT(frame) scm_frame_next (frame)
-
-#define SCM_FRAMEF_VOID		(1L << 2)
-#define SCM_FRAMEF_REAL		(1L << 3)
-#define SCM_FRAMEF_PROC 	(1L << 4)
-#define SCM_FRAMEF_EVAL_ARGS 	(1L << 5)
-#define SCM_FRAMEF_OVERFLOW	(1L << 6)
-
-#define SCM_FRAME_VOID_P(f)       (SCM_FRAME_FLAGS (f) & SCM_FRAMEF_VOID)
-#define SCM_FRAME_REAL_P(f)       (SCM_FRAME_FLAGS (f) & SCM_FRAMEF_REAL)
-#define SCM_FRAME_PROC_P(f)       (SCM_FRAME_FLAGS (f) & SCM_FRAMEF_PROC)
-#define SCM_FRAME_EVAL_ARGS_P(f)  (SCM_FRAME_FLAGS (f) & SCM_FRAMEF_EVAL_ARGS)
-#define SCM_FRAME_OVERFLOW_P(f)   (SCM_FRAME_FLAGS (f) & SCM_FRAMEF_OVERFLOW)
 
 
 
@@ -94,19 +55,6 @@ SCM_API SCM scm_stack_id (SCM stack);
 SCM_API SCM scm_stack_ref (SCM stack, SCM i);
 SCM_API SCM scm_stack_length (SCM stack);
 
-SCM_API SCM scm_frame_p (SCM obj);
-SCM_API SCM scm_last_stack_frame (SCM obj);
-SCM_API SCM scm_frame_number (SCM frame);
-SCM_API SCM scm_frame_source (SCM frame);
-SCM_API SCM scm_frame_procedure (SCM frame);
-SCM_API SCM scm_frame_arguments (SCM frame);
-SCM_API SCM scm_frame_previous (SCM frame);
-SCM_API SCM scm_frame_next (SCM frame);
-SCM_API SCM scm_frame_real_p (SCM frame);
-SCM_API SCM scm_frame_procedure_p (SCM frame);
-SCM_API SCM scm_frame_evaluating_args_p (SCM frame);
-SCM_API SCM scm_frame_overflow_p (SCM frame);
-
 SCM_INTERNAL void scm_init_stacks (void);
 
 #endif  /* SCM_STACKS_H */