mirror/guile
mirror/guile
1
Fork 0
mirror of https://git.savannah.gnu.org/git/guile.git synced 2025-06-10 22:10:21 +02:00
Code Activity

Optimize abort-to-prompt to avoid alloca

Browse source 
* libguile/vm.c (capture_delimited_continuation): Adapt to caller not
  truncating vp->sp to vp->fp before calling.
  (abort_to_prompt): Inline vm_abort and avoid the alloca.
This commit is contained in:
Andy Wingo 2018-06-26 17:08:24 +02:00
parent 770360e066
commit bf66fdca55
1 changed files with 23 additions and 38 deletions
Download patch file Download diff file Expand all files Collapse all files

61
libguile/vm.c
View file

@ -1329,8 +1329,10 @@ capture_delimited_continuation (struct scm_vm *vp,
scm_dynstack_relocate_prompts (dynstack, vp->stack_top - base_fp);
/* Capture from the base_fp to the top thunk application frame. */
vm_cont = scm_i_vm_capture_stack (base_fp, vp->fp, vp->sp, vp->ip, dynstack,
/* Capture from the base_fp to the top thunk application frame. Don't
capture values from the most recent frame, as they are the abort
args. */
vm_cont = scm_i_vm_capture_stack (base_fp, vp->fp, vp->fp, vp->ip, dynstack,
flags);
return scm_i_make_composable_continuation (vm_cont);
@ -1345,18 +1347,21 @@ scm_i_vm_abort (SCM *tag_and_argv, size_t n)
}
static void
vm_abort (struct scm_vm *vp, SCM tag, size_t n, SCM *argv,
jmp_buf *current_registers)
abort_to_prompt (scm_thread *thread, jmp_buf *current_registers)
{
SCM cont;
scm_t_dynstack *dynstack = &SCM_I_CURRENT_THREAD->dynstack;
struct scm_vm *vp = &thread->vm;
scm_t_dynstack *dynstack = &thread->dynstack;
SCM tag, cont;
size_t nargs;
scm_t_bits *prompt;
scm_t_dynstack_prompt_flags flags;
ptrdiff_t fp_offset, sp_offset;
union scm_vm_stack_element *fp, *sp;
uint32_t *ip;
jmp_buf *registers;
size_t i;
tag = SCM_FRAME_LOCAL (vp->fp, 1);
nargs = frame_locals_count (thread) - 2;
prompt = scm_dynstack_find_prompt (dynstack, tag,
&flags, &fp_offset, &sp_offset, &ip,
@ -1383,20 +1388,21 @@ vm_abort (struct scm_vm *vp, SCM tag, size_t n, SCM *argv,
/* Unwind. */
scm_dynstack_unwind (dynstack, prompt);
sp = sp - nargs - 1;
/* Shuffle abort arguments down to the prompt continuation. We have
to be jumping to an older part of the stack. */
if (sp < vp->sp)
abort ();
sp[nargs].as_scm = cont;
while (nargs--)
sp[nargs] = vp->sp[nargs];
/* Restore VM regs */
vp->fp = fp;
vp->sp = sp - n - 1;
vp->sp = sp;
vp->ip = ip;
/* Since we're jumping down, we should always have enough space. */
if (vp->sp < vp->stack_limit)
abort ();
/* Push vals */
vp->sp[n].as_scm = cont;
for (i = 0; i < n; i++)
vp->sp[n - i - 1].as_scm = argv[i];
/* Jump! */
longjmp (*registers, 1);
@ -1404,27 +1410,6 @@ vm_abort (struct scm_vm *vp, SCM tag, size_t n, SCM *argv,
abort ();
}
static void
abort_to_prompt (scm_thread *thread, jmp_buf *current_registers)
{
struct scm_vm *vp = &thread->vm;
SCM tag;
size_t nargs, i;
SCM *argv;
tag = SCM_FRAME_LOCAL (vp->fp, 1);
nargs = frame_locals_count (thread) - 2;
/* FIXME: Avoid this alloca. */
argv = alloca (nargs * sizeof (SCM));
for (i = 0; i < nargs; i++)
argv[i] = vp->sp[nargs - i - 1].as_scm;
vp->sp = vp->fp;
vm_abort (vp, tag, nargs, argv, current_registers);
}
SCM
scm_call_n (SCM proc, SCM *argv, size_t nargs)
{