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inline frame replacement in tail-call

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* libguile/programs.c (program_print): Only try to lookup write-program
  if the module system is booted.

* libguile/vm-engine.h (FREE_FRAME): Remove, it's now inlined everywhere.

* libguile/vm-i-system.c (tail-call): Inline FREE_FRAME, and implement
  the calling bits here. Will make things more hackable.
This commit is contained in:
Andy Wingo 2008-09-13 15:41:43 +02:00
parent 1dc8f8517c
commit 28106f547d
3 changed files with 48 additions and 35 deletions
Download patch file Download diff file Expand all files Collapse all files

2
libguile/programs.c
View file

@ -131,7 +131,7 @@ program_print (SCM program, SCM port, scm_print_state *pstate)
{
static int print_error = 0;
if (SCM_FALSEP (write_program))
if (SCM_FALSEP (write_program) && scm_module_system_booted_p)
write_program = scm_module_local_variable
(scm_c_resolve_module ("system vm program"),
scm_from_locale_symbol ("write-program"));

29
libguile/vm-engine.h
View file

@ -443,35 +443,6 @@ do { \
data[0] = external; \
}
#define FREE_FRAME() \
{ \
SCM *last_sp = sp; \
SCM *last_fp = fp; \
SCM *p = fp + bp->nargs + bp->nlocs; \
\
/* Restore pointers */ \
ip = SCM_FRAME_BYTE_CAST (p[3]); \
fp = SCM_FRAME_STACK_CAST (p[2]); \
\
if (!SCM_FALSEP (p[1])) \
{ \
/* Unlink the heap stack */ \
vp->this_frame = p[1]; \
} \
else \
{ \
/* Move stack items */ \
p += 4; \
sp = SCM_FRAME_LOWER_ADDRESS (last_fp); \
while (p <= last_sp) \
*sp++ = *p++; \
sp--; \
} \
stack_base = fp ? \
SCM_FRAME_UPPER_ADDRESS (fp) - 1 \
: vp->stack_base; \
}
#define CACHE_EXTERNAL() external = fp[bp->nargs + bp->nlocs]
/*

52
libguile/vm-i-system.c
View file

@ -442,7 +442,6 @@ VM_DEFINE_INSTRUCTION (call, "call", 1, -1, 1)
if (SCM_PROGRAM_P (x))
{
program = x;
vm_call_program:
CACHE_PROGRAM ();
INIT_ARGS ();
NEW_FRAME ();
@ -564,15 +563,58 @@ VM_DEFINE_INSTRUCTION (tail_call, "tail-call", 1, -1, 1)
APPLY_HOOK ();
NEXT;
}
/*
* Proper tail call
* Tail call, but not to self -- reuse the frame, keeping the ra and dl
*/
if (SCM_PROGRAM_P (x))
{
SCM *data, *tail_args, *dl;
int i;
scm_byte_t *ra;
EXIT_HOOK ();
FREE_FRAME ();
program = x;
goto vm_call_program;
/* save registers */
tail_args = stack_base + 2;
ra = SCM_FRAME_RETURN_ADDRESS (fp);
dl = SCM_FRAME_DYNAMIC_LINK (fp);
/* switch programs */
fp[-1] = program = x;
CACHE_PROGRAM ();
INIT_ARGS ();
nargs = bp->nargs;
/* new registers -- logically this would be better later, but let's make
sure we have space for the locals now */
data = SCM_FRAME_DATA_ADDRESS (fp);
ip = bp->base;
stack_base = data + 3;
sp = stack_base;
CHECK_OVERFLOW ();
/* copy args, bottom-up */
for (i = 0; i < nargs; i++)
fp[i] = tail_args[i];
/* init locals */
for (i = bp->nlocs; i; i--)
data[-i] = SCM_UNDEFINED;
/* and the external variables */
external = bp->external;
for (i = 0; i < bp->nexts; i++)
CONS (external, SCM_UNDEFINED, external);
/* Set frame data */
data[3] = (SCM)ra;
data[2] = (SCM)dl;
data[1] = SCM_BOOL_F;
data[0] = external;
ENTER_HOOK ();
APPLY_HOOK ();
NEXT;
}
#ifdef ENABLE_TRAMPOLINE
/* This seems to actually slow down the fibo test -- dunno why */