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authorAndy Wingo <wingo@pobox.com>2018-06-26 10:57:23 +0200
committerAndy Wingo <wingo@pobox.com>2018-06-26 11:09:36 +0200
commit5e8e816c61f99ef1d96ad186d949659bf3aa8853 (patch)
treeda62e39049d3bee7a311757e309428cb20e80b46
parent3b6bf20ef5d7d0de34de4fb7ba9777af29ba55ae (diff)
downloadguile-5e8e816c61f99ef1d96ad186d949659bf3aa8853.tar.gz
Reinstating undelimited continuations uses intrinsic
* libguile/continuations.h (scm_t_contregs): Remove "struct vm*" member; unneeded. * libguile/continuations.c (scm_i_make_continuation): No need to store continuation->vp. (scm_i_contregs): New internal function, replaces scm_i_contregs_vp and scm_i_contregs_vm_cont. (scm_i_check_continuation): Remove; moved to vm.c. (scm_i_reinstate_continuation): Add an abort(), to satisfy SCM_NORETURN. * libguile/intrinsics.h: Add new "reinstate-continuation!" intrinsic. * libguile/vm-engine.c (continuation-call): Use new reinstate-continuation! intrinsic. * libguile/vm.c (vm_return_to_continuation_inner): Move later in the file. (reinstate_continuation_x): New intrinsic. (scm_bootstrap_vm): Init new intrinsic.
-rw-r--r--libguile/continuations.c29
-rw-r--r--libguile/continuations.h8
-rw-r--r--libguile/intrinsics.h2
-rw-r--r--libguile/vm-engine.c9
-rw-r--r--libguile/vm.c128
5 files changed, 83 insertions, 93 deletions
diff --git a/libguile/continuations.c b/libguile/continuations.c
index 6446a565b..c99e0eb43 100644
--- a/libguile/continuations.c
+++ b/libguile/continuations.c
@@ -193,7 +193,6 @@ 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);
- continuation->vp = vp;
continuation->vm_cont = vm_cont;
saved_cookie = vp->resumable_prompt_cookie;
capture_auxiliary_stack (thread, continuation);
@@ -236,16 +235,13 @@ scm_i_continuation_to_frame (SCM continuation, struct scm_frame *frame)
return 0;
}
-struct scm_vm *
-scm_i_contregs_vp (SCM contregs)
+scm_t_contregs *
+scm_i_contregs (SCM contregs)
{
- return SCM_CONTREGS (contregs)->vp;
-}
+ if (!SCM_CONTREGSP (contregs))
+ abort ();
-SCM
-scm_i_contregs_vm_cont (SCM contregs)
-{
- return SCM_CONTREGS (contregs)->vm_cont;
+ return SCM_CONTREGS (contregs);
}
@@ -336,24 +332,11 @@ scm_dynthrow (SCM cont)
copy_stack_and_call (continuation, dst);
}
-
-void
-scm_i_check_continuation (SCM cont)
-{
- scm_i_thread *thread = SCM_I_CURRENT_THREAD;
- scm_t_contregs *continuation = SCM_CONTREGS (cont);
-
- if (!scm_is_eq (continuation->root, thread->continuation_root))
- scm_misc_error
- ("%continuation-call",
- "invoking continuation would cross continuation barrier: ~A",
- scm_list_1 (cont));
-}
-
void
scm_i_reinstate_continuation (SCM cont)
{
scm_dynthrow (cont);
+ abort (); /* Unreachable. */
}
SCM
diff --git a/libguile/continuations.h b/libguile/continuations.h
index a9ab5eae8..6b52f2649 100644
--- a/libguile/continuations.h
+++ b/libguile/continuations.h
@@ -49,7 +49,6 @@ typedef struct
#endif
size_t num_stack_items; /* size of the saved stack. */
SCM root; /* continuation root identifier. */
- struct scm_vm *vp; /* vm */
SCM vm_cont; /* vm's stack and regs */
/* The offset from the live stack location to this copy. This is
@@ -71,15 +70,12 @@ typedef struct
SCM_INTERNAL SCM scm_i_make_continuation (int *first,
struct scm_vm *vp,
SCM vm_cont);
-SCM_INTERNAL void scm_i_check_continuation (SCM cont);
-SCM_INTERNAL void scm_i_reinstate_continuation (SCM cont);
+SCM_INTERNAL void scm_i_reinstate_continuation (SCM cont) SCM_NORETURN;
-struct scm_frame;
SCM_INTERNAL int scm_i_continuation_to_frame (SCM cont,
struct scm_frame *frame);
-SCM_INTERNAL struct scm_vm* scm_i_contregs_vp (SCM contregs);
-SCM_INTERNAL SCM scm_i_contregs_vm_cont (SCM contregs);
+SCM_INTERNAL scm_t_contregs* scm_i_contregs (SCM contregs);
SCM_API void *scm_c_with_continuation_barrier (void *(*func)(void*), void *);
SCM_API SCM scm_with_continuation_barrier (SCM proc);
diff --git a/libguile/intrinsics.h b/libguile/intrinsics.h
index df1551529..5b183a62c 100644
--- a/libguile/intrinsics.h
+++ b/libguile/intrinsics.h
@@ -52,6 +52,7 @@ typedef void (*scm_t_thread_u32_u32_scm_u8_u8_intrinsic) (scm_i_thread*, uint32_
uint8_t);
typedef SCM (*scm_t_scm_from_scm_scm_intp_sp_intrinsic) (SCM, SCM, int*,
const union scm_vm_stack_element*);
+typedef void (*scm_t_thread_scm_noreturn_intrinsic) (scm_i_thread*, SCM) SCM_NORETURN;
#define SCM_FOR_ALL_VM_INTRINSICS(M) \
M(scm_from_scm_scm, add, "add", ADD) \
@@ -102,6 +103,7 @@ typedef SCM (*scm_t_scm_from_scm_scm_intp_sp_intrinsic) (SCM, SCM, int*,
M(thread_u32_u32_scm_u8_u8, bind_kwargs, "bind-kwargs", BIND_KWARGS) \
M(thread, push_interrupt_frame, "push-interrupt-frame", PUSH_INTERRUPT_FRAME) \
M(scm_from_scm_scm_intp_sp, foreign_call, "foreign-call", FOREIGN_CALL) \
+ M(thread_scm_noreturn, reinstate_continuation_x, "reinstate-continuation!", REINSTATE_CONTINUATION_X) \
/* Add new intrinsics here; also update scm_bootstrap_intrinsics. */
enum scm_vm_intrinsic
diff --git a/libguile/vm-engine.c b/libguile/vm-engine.c
index 8e863827d..dcbd96eb0 100644
--- a/libguile/vm-engine.c
+++ b/libguile/vm-engine.c
@@ -650,7 +650,7 @@ VM_NAME (scm_i_thread *thread, jmp_buf *registers, int resume)
ALLOC_FRAME (3);
SP_SET (1, ret);
- SP_SET (0, scm_from_int (err));
+ SP_SET (0, scm_vm_intrinsics.s64_to_scm (err));
NEXT (1);
}
@@ -674,12 +674,7 @@ VM_NAME (scm_i_thread *thread, jmp_buf *registers, int resume)
SCM_PROGRAM_FREE_VARIABLE_REF (FP_REF (0), contregs_idx);
SYNC_IP ();
- scm_i_check_continuation (contregs);
- vm_return_to_continuation (scm_i_contregs_vp (contregs),
- scm_i_contregs_vm_cont (contregs),
- FRAME_LOCALS_COUNT_FROM (1),
- sp);
- scm_i_reinstate_continuation (contregs);
+ scm_vm_intrinsics.reinstate_continuation_x (thread, contregs);
/* no NEXT */
abort ();
diff --git a/libguile/vm.c b/libguile/vm.c
index bafdcf26a..b3a680f47 100644
--- a/libguile/vm.c
+++ b/libguile/vm.c
@@ -182,63 +182,6 @@ scm_i_vm_capture_stack (union scm_vm_stack_element *stack_top,
return scm_cell (scm_tc7_vm_cont, (scm_t_bits) p);
}
-struct return_to_continuation_data
-{
- struct scm_vm_cont *cp;
- struct scm_vm *vp;
-};
-
-/* Called with the GC lock to prevent the stack marker from traversing a
- stack in an inconsistent state. */
-static void *
-vm_return_to_continuation_inner (void *data_ptr)
-{
- struct return_to_continuation_data *data = data_ptr;
- struct scm_vm *vp = data->vp;
- struct scm_vm_cont *cp = data->cp;
-
- /* We know that there is enough space for the continuation, because we
- captured it in the past. However there may have been an expansion
- since the capture, so we may have to re-link the frame
- pointers. */
- memcpy (vp->stack_top - cp->stack_size,
- cp->stack_bottom,
- cp->stack_size * sizeof (*cp->stack_bottom));
- vp->fp = vp->stack_top - cp->fp_offset;
- vm_restore_sp (vp, vp->stack_top - cp->stack_size);
-
- return NULL;
-}
-
-static void
-vm_return_to_continuation (struct scm_vm *vp, SCM cont, size_t n,
- union scm_vm_stack_element *argv)
-{
- struct scm_vm_cont *cp;
- union scm_vm_stack_element *argv_copy;
- struct return_to_continuation_data data;
-
- argv_copy = alloca (n * sizeof (*argv));
- memcpy (argv_copy, argv, n * sizeof (*argv));
-
- cp = SCM_VM_CONT_DATA (cont);
-
- data.cp = cp;
- data.vp = vp;
- GC_call_with_alloc_lock (vm_return_to_continuation_inner, &data);
-
- /* Now we have the continuation properly copied over. We just need to
- copy on an empty frame and the return values, as the continuation
- expects. */
- vm_push_sp (vp, vp->sp - 3 - n);
- vp->sp[n+2].as_scm = SCM_BOOL_F;
- vp->sp[n+1].as_scm = SCM_BOOL_F;
- vp->sp[n].as_scm = SCM_BOOL_F;
- memcpy(vp->sp, argv_copy, n * sizeof (union scm_vm_stack_element));
-
- vp->ip = cp->ra;
-}
-
SCM
scm_i_capture_current_stack (void)
{
@@ -1285,6 +1228,76 @@ push_interrupt_frame (scm_i_thread *thread)
SCM_FRAME_LOCAL (thread->vm.fp, 0) = proc;
}
+struct return_to_continuation_data
+{
+ struct scm_vm_cont *cp;
+ struct scm_vm *vp;
+};
+
+/* Called with the GC lock to prevent the stack marker from traversing a
+ stack in an inconsistent state. */
+static void *
+vm_return_to_continuation_inner (void *data_ptr)
+{
+ struct return_to_continuation_data *data = data_ptr;
+ struct scm_vm *vp = data->vp;
+ struct scm_vm_cont *cp = data->cp;
+
+ /* We know that there is enough space for the continuation, because we
+ captured it in the past. However there may have been an expansion
+ since the capture, so we may have to re-link the frame
+ pointers. */
+ memcpy (vp->stack_top - cp->stack_size,
+ cp->stack_bottom,
+ cp->stack_size * sizeof (*cp->stack_bottom));
+ vp->fp = vp->stack_top - cp->fp_offset;
+ vm_restore_sp (vp, vp->stack_top - cp->stack_size);
+
+ return NULL;
+}
+
+static void reinstate_continuation_x (scm_i_thread *thread, SCM cont) SCM_NORETURN;
+
+static void
+reinstate_continuation_x (scm_i_thread *thread, SCM cont)
+{
+ scm_t_contregs *continuation = scm_i_contregs (cont);
+ struct scm_vm *vp = &thread->vm;
+ struct scm_vm_cont *cp;
+ size_t n;
+ union scm_vm_stack_element *argv;
+ struct return_to_continuation_data data;
+
+ if (!scm_is_eq (continuation->root, thread->continuation_root))
+ scm_misc_error
+ ("%continuation-call",
+ "invoking continuation would cross continuation barrier: ~A",
+ scm_list_1 (cont));
+
+ n = frame_locals_count (thread) - 1,
+ argv = alloca (n * sizeof (*argv));
+ memcpy (argv, vp->sp, n * sizeof (*argv));
+
+ cp = SCM_VM_CONT_DATA (continuation->vm_cont);
+
+ data.cp = cp;
+ data.vp = vp;
+ GC_call_with_alloc_lock (vm_return_to_continuation_inner, &data);
+
+ /* Now we have the continuation properly copied over. We just need to
+ copy on an empty frame and the return values, as the continuation
+ expects. */
+ vm_push_sp (vp, vp->sp - 3 - n);
+ vp->sp[n+2].as_scm = SCM_BOOL_F;
+ vp->sp[n+1].as_scm = SCM_BOOL_F;
+ vp->sp[n].as_scm = SCM_BOOL_F;
+ memcpy(vp->sp, argv, n * sizeof (union scm_vm_stack_element));
+
+ vp->ip = cp->ra;
+
+ scm_i_reinstate_continuation (cont);
+}
+
SCM
scm_call_n (SCM proc, SCM *argv, size_t nargs)
{
@@ -1628,6 +1641,7 @@ scm_bootstrap_vm (void)
scm_vm_intrinsics.compute_kwargs_npositional = compute_kwargs_npositional;
scm_vm_intrinsics.bind_kwargs = bind_kwargs;
scm_vm_intrinsics.push_interrupt_frame = push_interrupt_frame;
+ scm_vm_intrinsics.reinstate_continuation_x = reinstate_continuation_x;
sym_vm_run = scm_from_latin1_symbol ("vm-run");
sym_vm_error = scm_from_latin1_symbol ("vm-error");