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Refactor continuation capture in VM

Browse source 
* libguile/continuations.h:
* libguile/continuations.c (scm_i_make_continuation): Refactor to expect
  registers to already be captured.
* libguile/scm.h (scm_i_thread): Add forward decl.
* libguile/threads.h (struct scm_i_thread): Just fill in the struct
  type.
* libguile/vm-engine.c (call/cc); Use the registers already captured
  before entering the VM.
This commit is contained in:
Andy Wingo 2018-06-26 11:25:07 +02:00
parent 185d19dfb1
commit 51e35158ba
5 changed files with 19 additions and 49 deletions
Download patch file Download diff file Expand all files Collapse all files

21
libguile/continuations.c
View file

@ -166,18 +166,12 @@ restore_auxiliary_stack (scm_i_thread *thread, scm_t_contregs *continuation)
#endif
}
/* this may return more than once: the first time with the escape
procedure, then subsequently with SCM_UNDEFINED (the vals already having been
placed on the VM stack). */
#define FUNC_NAME "scm_i_make_continuation"
SCM
scm_i_make_continuation (int *first, struct scm_vm *vp, SCM vm_cont)
scm_i_make_continuation (jmp_buf *registers, scm_i_thread *thread, SCM vm_cont)
{
scm_i_thread *thread = SCM_I_CURRENT_THREAD;
SCM cont;
scm_t_contregs *continuation;
long stack_size;
const void *saved_cookie;
SCM_STACKITEM * src;
SCM_FLUSH_REGISTER_WINDOWS;
@ -193,23 +187,14 @@ scm_i_make_continuation (int *first, struct scm_vm *vp, SCM vm_cont)
#endif
continuation->offset = continuation->stack - src;
memcpy (continuation->stack, src, sizeof (SCM_STACKITEM) * stack_size);
memcpy (continuation->jmpbuf, registers, sizeof (*registers));
continuation->vm_cont = vm_cont;
saved_cookie = vp->resumable_prompt_cookie;
capture_auxiliary_stack (thread, continuation);
SCM_NEWSMOB (cont, tc16_continuation, continuation);
*first = !setjmp (continuation->jmpbuf);
if (*first)
return make_continuation_trampoline (cont);
else
{
vp->resumable_prompt_cookie = saved_cookie;
scm_gc_after_nonlocal_exit ();
return SCM_UNDEFINED;
}
return make_continuation_trampoline (cont);
}
#undef FUNC_NAME
int
scm_i_continuation_to_frame (SCM continuation, struct scm_frame *frame)

4
libguile/continuations.h
View file

@ -67,8 +67,8 @@ typedef struct
SCM_INTERNAL SCM scm_i_make_continuation (int *first,
struct scm_vm *vp,
SCM_INTERNAL SCM scm_i_make_continuation (jmp_buf *registers,
scm_i_thread *thread,
SCM vm_cont);
SCM_INTERNAL void scm_i_reinstate_continuation (SCM cont) SCM_NORETURN;

2
libguile/scm.h
View file

@ -827,7 +827,7 @@ typedef int32_t scm_t_wchar;
struct scm_frame;
struct scm_vm;
union scm_vm_stack_element;
typedef struct scm_i_thread scm_i_thread; /* FIXME: Rename. */

4
libguile/threads.h
View file

@ -48,7 +48,7 @@ SCM_API scm_t_bits scm_tc16_condvar;
struct scm_thread_wake_data;
typedef struct scm_i_thread {
struct scm_i_thread {
struct scm_i_thread *next_thread;
SCM handle;
@ -105,7 +105,7 @@ typedef struct scm_i_thread {
struct scm_vm vm;
SCM_STACKITEM *base;
jmp_buf regs;
} scm_i_thread;
};
#define SCM_I_IS_THREAD(x) SCM_SMOB_PREDICATE (scm_tc16_thread, x)
#define SCM_I_THREAD_DATA(x) ((scm_i_thread *) SCM_SMOB_DATA (x))

37
libguile/vm-engine.c
View file

@ -758,7 +758,6 @@ VM_NAME (scm_i_thread *thread, jmp_buf *registers, int resume)
{
SCM vm_cont, cont;
scm_t_dynstack *dynstack;
int first;
SYNC_IP ();
dynstack = scm_dynstack_capture_all (&thread->dynstack);
@ -768,35 +767,21 @@ VM_NAME (scm_i_thread *thread, jmp_buf *registers, int resume)
SCM_FRAME_RETURN_ADDRESS (VP->fp),
dynstack,
0);
/* FIXME: Seems silly to capture the registers here, when they are
already captured in the registers local, which here we are
copying out to the heap; and likewise, the setjmp(&registers)
code already has the non-local return handler. But oh
well! */
cont = scm_i_make_continuation (&first, VP, vm_cont);
cont = scm_i_make_continuation (registers, thread, vm_cont);
if (first)
{
RESET_FRAME (2);
RESET_FRAME (2);
SP_SET (1, SP_REF (0));
SP_SET (0, cont);
SP_SET (1, SP_REF (0));
SP_SET (0, cont);
if (SCM_LIKELY (SCM_PROGRAM_P (SP_REF (1))))
ip = SCM_PROGRAM_CODE (SP_REF (1));
else
ip = (uint32_t *) vm_apply_non_program_code;
APPLY_HOOK ();
NEXT (0);
}
if (SCM_LIKELY (SCM_PROGRAM_P (SP_REF (1))))
ip = SCM_PROGRAM_CODE (SP_REF (1));
else
{
CACHE_REGISTER ();
ABORT_CONTINUATION_HOOK ();
NEXT (0);
}
ip = (uint32_t *) vm_apply_non_program_code;
APPLY_HOOK ();
NEXT (0);
}
/* abort _:24