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Remove MVRA from VM frames

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* libguile/_scm.h (SCM_OBJCODE_MINOR_VERSION): Bump for frame layout
  change.

* libguile/frames.c: Update some static checks.
  (scm_frame_num_locals, scm_frame_local_ref, scm_frame_local_set_x):
  Update to not skip over uninitialized frames, as that's not a thing
  any more.

* libguile/frames.h: Update to remove MVRA.  Woo!

* libguile/vm-engine.c (ALLOC_FRAME, RETURN_ONE_VALUE):
  (rtl_vm_engine): Update for 3 words per frame instead of 4.

* libguile/vm.c (vm_return_to_continuation): Likewise.

* module/language/cps/slot-allocation.scm (allocate-slots): 3 words per
  frame, not 4.

* module/system/vm/assembler.scm (*bytecode-minor-version*): Bump.  Also
  remove a couple of tc7's that aren't around any more.
This commit is contained in:
Andy Wingo 2013-11-15 17:13:10 +01:00
parent 840ec33422
commit f8085163d6
7 changed files with 45 additions and 100 deletions
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40
libguile/frames.h
View file

@ -50,21 +50,26 @@
| Program | <- fp - 1
+==================+
| Return address | <- SCM_FRAME_UPPER_ADDRESS (fp)
| MV return address|
| Dynamic link | <- fp - 4 = SCM_FRAME_DATA_ADDRESS (fp) = SCM_FRAME_LOWER_ADDRESS (fp)
| Dynamic link | <- fp - 3 = SCM_FRAME_DATA_ADDRESS (fp) = SCM_FRAME_LOWER_ADDRESS (fp)
+==================+
| |
As can be inferred from this drawing, it is assumed that
`sizeof (SCM *) == sizeof (SCM)', since pointers (the `link' parts) are
assumed to be as long as SCM objects. */
assumed to be as long as SCM objects.
When a program returns multiple values, it will shuffle them down to
start contiguously from slot 1, as for a tail call. This means that
when the caller goes to access them, there are 2 or 3 empty words
between the top of the caller stack and the bottom of the values,
corresponding to the frame that was just popped.
*/
/* This structure maps to the contents of a VM stack frame. It can
alias a frame directly. */
struct scm_vm_frame
{
SCM *dynamic_link;
scm_t_uint8 *mv_return_address;
scm_t_uint8 *return_address;
SCM program;
SCM stack[1]; /* Variable-length */
@ -73,7 +78,7 @@ struct scm_vm_frame
#define SCM_FRAME_STRUCT(fp) \
((struct scm_vm_frame *) SCM_FRAME_DATA_ADDRESS (fp))
#define SCM_FRAME_DATA_ADDRESS(fp) (((SCM *) (fp)) - 4)
#define SCM_FRAME_DATA_ADDRESS(fp) (((SCM *) (fp)) - 3)
#define SCM_FRAME_STACK_ADDRESS(fp) (SCM_FRAME_STRUCT (fp)->stack)
#define SCM_FRAME_UPPER_ADDRESS(fp) ((SCM*)&SCM_FRAME_STRUCT (fp)->return_address)
#define SCM_FRAME_LOWER_ADDRESS(fp) ((SCM*)SCM_FRAME_STRUCT (fp))
@ -85,8 +90,6 @@ struct scm_vm_frame
(SCM_FRAME_STRUCT (fp)->return_address)
#define SCM_FRAME_SET_RETURN_ADDRESS(fp, ra) \
SCM_FRAME_STRUCT (fp)->return_address = (ra)
#define SCM_FRAME_SET_MV_RETURN_ADDRESS(fp, mvra) \
SCM_FRAME_STRUCT (fp)->mv_return_address = (mvra)
#define SCM_FRAME_DYNAMIC_LINK(fp) \
(SCM_FRAME_STRUCT (fp)->dynamic_link)
#define SCM_FRAME_SET_DYNAMIC_LINK(fp, dl) \
@ -97,34 +100,13 @@ struct scm_vm_frame
(SCM_FRAME_STRUCT (fp)->program)
/*
* RTL frames
*/
/* The frame format for the new RTL programs is almost like that for the
stack-vm programs. They differ in their handling of MV returns,
however. For RTL, every call is an MV call: every call has an MVRA.
Unlike the stack-vm programs, the MVRA for RTL programs is computable
from the RA -- it's always one word (4 bytes) before the RA.
Until we completely migrate to the RTL VM, we will also write the
MVRA to the stack.
When an RTL program returns multiple values, it will shuffle them
down to start contiguously from slot 0, as for a tail call. This
means that when the caller goes to access them, there are 2 or 3
empty words between the top of the caller stack and the bottom of the
values, corresponding to the frame that was just popped.
*/
/* FIXME: Replace SCM_FRAME_RETURN_ADDRESS with these. */
#define SCM_FRAME_RTL_RETURN_ADDRESS(fp) \
((scm_t_uint32 *) SCM_FRAME_RETURN_ADDRESS (fp))
#define SCM_FRAME_SET_RTL_RETURN_ADDRESS(fp, ip) \
SCM_FRAME_SET_RETURN_ADDRESS (fp, (scm_t_uint8 *) (ip))
#define SCM_FRAME_SET_RTL_MV_RETURN_ADDRESS(fp, ip) \
SCM_FRAME_SET_MV_RETURN_ADDRESS (fp, (scm_t_uint8 *) (ip))
/*
* Heap frames