Continuations capture machine code address

* libguile/continuations.c (scm_i_continuation_to_frame): Adapt to vra
  field renaming.
  (scm_i_reinstate_continuation, grow_stack, copy_stack_and_call)
  (scm_dynthrow): Take mra of continuation.  Set on the vp before the
  longjmp.
* libguile/continuations.h: Update scm_i_reinstate_continuation
  prototype.
* libguile/dynstack.h:
* libguile/control.c (scm_suspendable_continuation_p):
* libguile/dynstack.c (PROMPT_WORDS, PROMPT_VRA, PROMPT_MRA):
  (PROMPT_JMPBUF, scm_dynstack_push_prompt, scm_dynstack_find_prompt)
  (scm_dynstack_wind_prompt): Store both virtual and machine return
  addresses on the dynstack, for prompts.
* libguile/eval.c (eval): Pass NULL for mra.
* libguile/intrinsics.c (push_prompt): Add mra arg, and pass it to the
  dynstack.
* libguile/intrinsics.h: Update prototypes so that continuation-related
  intrinsics can save and restore the MRA.
* libguile/jit.h:
* libguile/jit.c: Return VRA when JIT code needs to tier down.
* libguile/stacks.c (find_prompt, scm_make_stack)
* libguile/throw.c (catch): Adapt find-prompt calls.
* libguile/vm-engine.c (instrument-entry, instrument-loop): Add logic to
  continue with vcode after the mcode finishes.
  (compose-continuation, capture-continuation, abort, prompt): Add logic
  to pass NULL as captured MRA, but continue with mcode from new
  continuations, if appropriate.
* libguile/vm.c (scm_i_vm_cont_to_frame, capture_stack)
  (scm_i_capture_current_stack, reinstate_continuation_x)
  (capture_continuation, compose_continuation_inner, compose_continuation)
  (capture_delimited_continuation, abort_to_prompt): Adapt to plumb
  around machine code continuations.
  (scm_call_n): Check "mra_after_abort" field for machine code
  continuation, if any.
* libguile/vm.h (struct scm_vm): Add "mra_after_abort" field.
  (struct scm_vm_cont): Rename "ra" field to "vra" and add "mra" field.

libguile/continuations.c

@@ -228,7 +228,7 @@ scm_i_continuation_to_frame (SCM continuation, struct scm_frame *frame)
       frame->stack_holder = data;
       frame->fp_offset = data->fp_offset;
       frame->sp_offset = data->stack_size;
-      frame->ip = data->ra;
+      frame->ip = data->vra;
 
       return 1;
     }
@@ -261,7 +261,7 @@ scm_i_contregs (SCM contregs)
  * with their correct stack.
  */
 
-static void scm_dynthrow (SCM);
+static void scm_dynthrow (SCM, uint8_t *);
 
 /* Grow the stack by a fixed amount to provide space to copy in the
  * continuation.  Possibly this function has to be called several times
@@ -273,12 +273,12 @@ static void scm_dynthrow (SCM);
 static scm_t_bits scm_i_dummy;
 
 static void 
-grow_stack (SCM cont)
+grow_stack (SCM cont, uint8_t *mra)
 {
   scm_t_bits growth[100];
 
   scm_i_dummy = (scm_t_bits) growth;
-  scm_dynthrow (cont);
+  scm_dynthrow (cont, mra);
 }
 
 
@@ -289,7 +289,7 @@ grow_stack (SCM cont)
 
 static void
 copy_stack_and_call (scm_t_contregs *continuation,
-		     SCM_STACKITEM * dst)
+		     SCM_STACKITEM * dst, uint8_t *mra)
 {
   scm_t_dynstack *dynstack;
   scm_t_bits *joint;
@@ -305,6 +305,7 @@ copy_stack_and_call (scm_t_contregs *continuation,
 
   scm_dynstack_wind (&thread->dynstack, joint);
 
+  thread->vm.mra_after_abort = mra;
   longjmp (continuation->jmpbuf, 1);
 }
 
@@ -313,7 +314,7 @@ copy_stack_and_call (scm_t_contregs *continuation,
  * actual copying and continuation calling.
  */
 static void 
-scm_dynthrow (SCM cont)
+scm_dynthrow (SCM cont, uint8_t *mra)
 {
   scm_thread *thread = SCM_I_CURRENT_THREAD;
   scm_t_contregs *continuation = SCM_CONTREGS (cont);
@@ -326,17 +327,17 @@ scm_dynthrow (SCM cont)
 #else
   dst -= continuation->num_stack_items;
   if (dst <= &stack_top_element)
-    grow_stack (cont);
+    grow_stack (cont, mra);
 #endif /* def SCM_STACK_GROWS_UP */
 
   SCM_FLUSH_REGISTER_WINDOWS;
-  copy_stack_and_call (continuation, dst);
+  copy_stack_and_call (continuation, dst, mra);
 }
 
 void
-scm_i_reinstate_continuation (SCM cont)
+scm_i_reinstate_continuation (SCM cont, uint8_t *mra)
 {
-  scm_dynthrow (cont);
+  scm_dynthrow (cont, mra);
   abort (); /* Unreachable.  */
 }
 

libguile/continuations.h

@@ -68,7 +68,8 @@ typedef struct
 
 
 SCM_INTERNAL SCM scm_i_make_continuation (scm_thread *thread, SCM vm_cont);
-SCM_INTERNAL void scm_i_reinstate_continuation (SCM cont) SCM_NORETURN;
+SCM_INTERNAL void scm_i_reinstate_continuation (SCM cont,
+                                                uint8_t *mra) SCM_NORETURN;
 
 SCM_INTERNAL int scm_i_continuation_to_frame (SCM cont,
                                               struct scm_frame *frame);

libguile/control.c

@@ -138,7 +138,7 @@ scm_suspendable_continuation_p (SCM tag)
   jmp_buf *registers;
 
   if (scm_dynstack_find_prompt (&thread->dynstack, tag, &flags,
-                                NULL, NULL, NULL, &registers))
+                                NULL, NULL, NULL, NULL, &registers))
     return scm_from_bool (registers == thread->vm.registers);
 
   return SCM_BOOL_F;

libguile/dynstack.c

@@ -38,14 +38,15 @@
 
 
 
-#define PROMPT_WORDS 5
+#define PROMPT_WORDS 6
 #define PROMPT_KEY(top) (SCM_PACK ((top)[0]))
 #define PROMPT_FP(top) ((ptrdiff_t) ((top)[1]))
 #define SET_PROMPT_FP(top, fp) do { top[1] = (scm_t_bits)(fp); } while (0)
 #define PROMPT_SP(top) ((ptrdiff_t) ((top)[2]))
 #define SET_PROMPT_SP(top, sp) do { top[2] = (scm_t_bits)(sp); } while (0)
-#define PROMPT_IP(top) ((uint32_t *) ((top)[3]))
+#define PROMPT_VRA(top) ((uint32_t *) ((top)[3]))
-#define PROMPT_JMPBUF(top) ((jmp_buf *) ((top)[4]))
+#define PROMPT_MRA(top) ((uint8_t *) ((top)[4]))
+#define PROMPT_JMPBUF(top) ((jmp_buf *) ((top)[5]))
 
 #define WINDER_WORDS 2
 #define WINDER_PROC(top) ((scm_t_guard) ((top)[0]))
@@ -197,7 +198,7 @@ scm_dynstack_push_prompt (scm_t_dynstack *dynstack,
                           scm_t_dynstack_prompt_flags flags,
                           SCM key,
                           ptrdiff_t fp_offset, ptrdiff_t sp_offset,
-                          uint32_t *ip, jmp_buf *registers)
+                          uint32_t *vra, uint8_t *mra, jmp_buf *registers)
 {
   scm_t_bits *words;
 
@@ -206,8 +207,9 @@ scm_dynstack_push_prompt (scm_t_dynstack *dynstack,
   words[0] = SCM_UNPACK (key);
   words[1] = (scm_t_bits) fp_offset;
   words[2] = (scm_t_bits) sp_offset;
-  words[3] = (scm_t_bits) ip;
+  words[3] = (scm_t_bits) vra;
-  words[4] = (scm_t_bits) registers;
+  words[4] = (scm_t_bits) mra;
+  words[5] = (scm_t_bits) registers;
 }
 
 void
@@ -500,7 +502,7 @@ scm_t_bits*
 scm_dynstack_find_prompt (scm_t_dynstack *dynstack, SCM key,
                           scm_t_dynstack_prompt_flags *flags,
                           ptrdiff_t *fp_offset, ptrdiff_t *sp_offset,
-                          uint32_t **ip, jmp_buf **registers)
+                          uint32_t **vra, uint8_t **mra, jmp_buf **registers)
 {
   scm_t_bits *walk;
 
@@ -518,8 +520,10 @@ scm_dynstack_find_prompt (scm_t_dynstack *dynstack, SCM key,
             *fp_offset = PROMPT_FP (walk);
           if (sp_offset)
             *sp_offset = PROMPT_SP (walk);
-          if (ip)
+          if (vra)
-            *ip = PROMPT_IP (walk);
+            *vra = PROMPT_VRA (walk);
+          if (mra)
+            *mra = PROMPT_MRA (walk);
           if (registers)
             *registers = PROMPT_JMPBUF (walk);
           return walk;
@@ -593,7 +597,8 @@ scm_dynstack_wind_prompt (scm_t_dynstack *dynstack, scm_t_bits *item,
                             PROMPT_KEY (item),
                             PROMPT_FP (item) + base_fp_offset,
                             PROMPT_SP (item) + base_fp_offset,
-                            PROMPT_IP (item),
+                            PROMPT_VRA (item),
+                            PROMPT_MRA (item),
                             registers);
 }
 

libguile/dynstack.h

@@ -160,7 +160,8 @@ SCM_INTERNAL void scm_dynstack_push_prompt (scm_t_dynstack *,
                                             SCM key,
                                             ptrdiff_t fp_offset,
                                             ptrdiff_t sp_offset,
-                                            uint32_t *ip,
+                                            uint32_t *vra,
+                                            uint8_t *mra,
                                             jmp_buf *registers);
 SCM_INTERNAL void scm_dynstack_push_dynwind (scm_t_dynstack *,
                                              SCM enter, SCM leave);
@@ -201,6 +202,7 @@ SCM_INTERNAL scm_t_bits* scm_dynstack_find_prompt (scm_t_dynstack *, SCM,
                                                    ptrdiff_t *,
                                                    ptrdiff_t *,
                                                    uint32_t **,
+                                                   uint8_t **,
                                                    jmp_buf **);
 
 SCM_INTERNAL SCM scm_dynstack_find_old_fluid_value (scm_t_dynstack *,

libguile/eval.c

@@ -441,6 +441,7 @@ eval (SCM x, SCM env)
         jmp_buf registers;
         jmp_buf *prev_registers;
         ptrdiff_t saved_stack_depth;
+        uint8_t *mra = NULL;
 
         k = EVAL1 (CAR (mx), env);
         handler = EVAL1 (CDDR (mx), env);
@@ -454,7 +455,7 @@ eval (SCM x, SCM env)
                                   k,
                                   t->vm.stack_top - t->vm.fp,
                                   saved_stack_depth,
-                                  t->vm.ip,
+                                  t->vm.ip, mra,
                                   &registers);
 
         prev_registers = t->vm.registers;

libguile/intrinsics.c

@@ -349,7 +349,8 @@ current_module (scm_thread *thread)
 
 static void
 push_prompt (scm_thread *thread, uint8_t escape_only_p,
-             SCM tag, const union scm_vm_stack_element *sp, uint32_t *ra)
+             SCM tag, const union scm_vm_stack_element *sp, uint32_t *vra,
+             uint8_t *mra)
 {
   struct scm_vm *vp = &thread->vm;
   scm_t_dynstack_prompt_flags flags;
@@ -357,7 +358,7 @@ push_prompt (scm_thread *thread, uint8_t escape_only_p,
   flags = escape_only_p ? SCM_F_DYNSTACK_PROMPT_ESCAPE_ONLY : 0;
   scm_dynstack_push_prompt (&thread->dynstack, flags, tag,
                             vp->stack_top - vp->fp, vp->stack_top - sp,
-                            ra, thread->vm.registers);
+                            vra, mra, thread->vm.registers);
 }
 
 void

libguile/intrinsics.h

@@ -61,12 +61,15 @@ typedef void (*scm_t_scm_noreturn_intrinsic) (SCM) SCM_NORETURN;
 typedef void (*scm_t_u32_noreturn_intrinsic) (uint32_t) SCM_NORETURN;
 typedef SCM (*scm_t_scm_from_thread_u64_intrinsic) (scm_thread*, uint64_t);
 typedef SCM (*scm_t_scm_from_thread_intrinsic) (scm_thread*);
-typedef void (*scm_t_thread_u8_scm_sp_vra_intrinsic) (scm_thread*,
+typedef void (*scm_t_thread_u8_scm_sp_vra_mra_intrinsic) (scm_thread*,
                                                           uint8_t, SCM,
                                                           const union scm_vm_stack_element*,
-                                                      uint32_t*);
+                                                          uint32_t*, uint8_t*);
 typedef void (*scm_t_thread_mra_intrinsic) (scm_thread*, uint8_t*);
 typedef uint32_t* (*scm_t_vra_from_thread_intrinsic) (scm_thread*);
+typedef uint8_t* (*scm_t_mra_from_thread_scm_intrinsic) (scm_thread*, SCM);
+typedef uint8_t* (*scm_t_mra_from_thread_mra_intrinsic) (scm_thread*, uint8_t*);
+typedef SCM (*scm_t_scm_from_thread_mra_intrinsic) (scm_thread*, uint8_t*);
 
 #define SCM_FOR_ALL_VM_INTRINSICS(M) \
   M(scm_from_scm_scm, add, "add", ADD) \
@@ -118,10 +121,10 @@ typedef uint32_t* (*scm_t_vra_from_thread_intrinsic) (scm_thread*);
   M(thread_mra, push_interrupt_frame, "push-interrupt-frame", PUSH_INTERRUPT_FRAME) \
   M(thread_scm_scm, foreign_call, "foreign-call", FOREIGN_CALL) \
   M(thread_scm_noreturn, reinstate_continuation_x, "reinstate-continuation!", REINSTATE_CONTINUATION_X) \
-  M(scm_from_thread, capture_continuation, "capture-continuation", CAPTURE_CONTINUATION) \
+  M(scm_from_thread_mra, capture_continuation, "capture-continuation", CAPTURE_CONTINUATION) \
-  M(thread_scm, compose_continuation, "compose-continuation", COMPOSE_CONTINUATION) \
+  M(mra_from_thread_scm, compose_continuation, "compose-continuation", COMPOSE_CONTINUATION) \
   M(int_from_scm, rest_arg_length, "rest-arg-length", REST_ARG_LENGTH) \
-  M(thread, abort_to_prompt, "abort-to-prompt", ABORT_TO_PROMPT) \
+  M(mra_from_thread_mra, abort_to_prompt, "abort-to-prompt", ABORT_TO_PROMPT) \
   M(scm_scm_noreturn, throw_, "throw", THROW) \
   M(scm_scm_noreturn, throw_with_value, "throw/value", THROW_WITH_VALUE) \
   M(scm_scm_noreturn, throw_with_value_and_data, "throw/value+data", THROW_WITH_VALUE_AND_DATA) \
@@ -132,7 +135,7 @@ typedef uint32_t* (*scm_t_vra_from_thread_intrinsic) (scm_thread*);
   M(vra_from_thread, get_callee_vcode, "get-callee-vcode", GET_CALLEE_VCODE) \
   M(scm_from_thread_u64, allocate_words, "allocate-words", ALLOCATE_WORDS) \
   M(scm_from_thread, current_module, "current-module", CURRENT_MODULE) \
-  M(thread_u8_scm_sp_vra, push_prompt, "push-prompt", PUSH_PROMPT) \
+  M(thread_u8_scm_sp_vra_mra, push_prompt, "push-prompt", PUSH_PROMPT)     \
   M(thread_scm, unpack_values_object, "unpack-values-object", UNPACK_VALUES_OBJECT) \
   M(thread, invoke_apply_hook, "invoke-apply-hook", INVOKE_APPLY_HOOK) \
   M(thread, invoke_return_hook, "invoke-return-hook", INVOKE_RETURN_HOOK) \

libguile/jit.c

@@ -1215,10 +1215,11 @@ scm_jit_compute_mcode (scm_thread *thread, struct scm_jit_function_data *data)
   return NULL;
 }
 
-void
+uint32_t *
 scm_jit_enter_mcode (scm_thread *thread, const uint8_t *mcode)
 {
   abort ();
+  return NULL;
 }
 
 void

libguile/jit.h

@@ -53,7 +53,8 @@ enum scm_jit_counter_value
 
 SCM_INTERNAL const uint8_t *scm_jit_compute_mcode (scm_thread *thread,
                                                    struct scm_jit_function_data *data);
-SCM_INTERNAL void scm_jit_enter_mcode (scm_thread *thread, const uint8_t *mcode);
+SCM_INTERNAL uint32_t *scm_jit_enter_mcode (scm_thread *thread,
+                                            const uint8_t *mcode);
 
 SCM_INTERNAL void scm_init_jit (void);
 

libguile/stacks.c

@@ -108,7 +108,7 @@ find_prompt (SCM key)
   ptrdiff_t fp_offset;
 
   if (!scm_dynstack_find_prompt (&SCM_I_CURRENT_THREAD->dynstack, key,
-                                 NULL, &fp_offset, NULL, NULL, NULL))
+                                 NULL, &fp_offset, NULL, NULL, NULL, NULL))
     scm_misc_error ("make-stack", "Prompt tag not found while narrowing stack",
                     scm_list_1 (key));
 
@@ -334,7 +334,7 @@ SCM_DEFINE (scm_make_stack, "make-stack", 1, 0, 1,
       frame.stack_holder = c;
       frame.fp_offset = c->fp_offset;
       frame.sp_offset = c->stack_size;
-      frame.ip = c->ra;
+      frame.ip = c->vra;
     }
   else if (SCM_VM_FRAME_P (obj))
     {

libguile/throw.c

@@ -88,6 +88,7 @@ catch (SCM tag, SCM thunk, SCM handler, SCM pre_unwind_handler)
   jmp_buf registers;
   jmp_buf *prev_registers;
   ptrdiff_t saved_stack_depth;
+  uint8_t *mra = NULL;
 
   if (!scm_is_eq (tag, SCM_BOOL_T) && !scm_is_symbol (tag))
     scm_wrong_type_arg ("catch", 1, tag);
@@ -119,6 +120,7 @@ catch (SCM tag, SCM thunk, SCM handler, SCM pre_unwind_handler)
                             t->vm.stack_top - t->vm.fp,
                             saved_stack_depth,
                             t->vm.ip,
+                            mra,
                             &registers);
   scm_dynstack_push_fluid (dynstack, exception_handler_fluid, eh,
                            dynamic_state);

libguile/vm-engine.c

@@ -472,8 +472,8 @@ VM_NAME (scm_thread *thread)
 
           if (mcode)
             {
-              scm_jit_enter_mcode (thread, mcode);
+              ip = scm_jit_enter_mcode (thread, mcode);
-              CACHE_REGISTER ();
+              CACHE_SP ();
               NEXT (0);
             }
         }
@@ -672,15 +672,26 @@ VM_NAME (scm_thread *thread)
     {
       SCM vmcont;
       uint32_t cont_idx;
+      uint8_t *mcode;
 
       UNPACK_24 (op, cont_idx);
       vmcont = SCM_PROGRAM_FREE_VARIABLE_REF (FP_REF (0), cont_idx);
 
       SYNC_IP ();
-      CALL_INTRINSIC (compose_continuation, (thread, vmcont));
+      mcode = CALL_INTRINSIC (compose_continuation, (thread, vmcont));
+
+      if (mcode)
+        {
+          ip = scm_jit_enter_mcode (thread, mcode);
+          CACHE_SP ();
+          NEXT (0);
+        }
+      else
+        {
           CACHE_REGISTER ();
           NEXT (0);
         }
+    }
 
   /* instrument-loop _:24 data:32
    *
@@ -705,8 +716,8 @@ VM_NAME (scm_thread *thread)
 
           if (mcode)
             {
-              scm_jit_enter_mcode (thread, mcode);
+              ip = scm_jit_enter_mcode (thread, mcode);
-              CACHE_REGISTER ();
+              CACHE_SP ();
               NEXT (0);
             }
         }
@@ -724,11 +735,12 @@ VM_NAME (scm_thread *thread)
   VM_DEFINE_OP (15, capture_continuation, "capture-continuation", DOP1 (X8_S24))
     {
       uint32_t dst;
+      uint8_t *mra = NULL;
 
       UNPACK_24 (op, dst);
 
       SYNC_IP ();
-      SP_SET (dst, CALL_INTRINSIC (capture_continuation, (thread)));
+      SP_SET (dst, CALL_INTRINSIC (capture_continuation, (thread, mra)));
 
       NEXT (1);
     }
@@ -741,20 +753,33 @@ VM_NAME (scm_thread *thread)
    */
   VM_DEFINE_OP (16, abort, "abort", OP1 (X32))
     {
+      uint8_t *mcode = NULL;
+
       /* FIXME: Really we should capture the caller's registers.  Until
          then, manually advance the IP so that when the prompt resumes,
          it continues with the next instruction.  */
       ip++;
       SYNC_IP ();
-      CALL_INTRINSIC (abort_to_prompt, (thread));
+      mcode = CALL_INTRINSIC (abort_to_prompt, (thread, mcode));
 
       /* If abort_to_prompt returned, that means there were no
          intervening C frames to jump over, so we just continue
          directly.  */
-      CACHE_REGISTER ();
+
       ABORT_CONTINUATION_HOOK ();
+
+      if (mcode)
+        {
+          ip = scm_jit_enter_mcode (thread, mcode);
+          CACHE_SP ();
           NEXT (0);
         }
+      else
+        {
+          CACHE_REGISTER ();
+          NEXT (0);
+        }
+    }
 
   /* builtin-ref dst:12 idx:12
    *
@@ -1623,6 +1648,7 @@ VM_NAME (scm_thread *thread)
       uint32_t tag, proc_slot;
       int32_t offset;
       uint8_t escape_only_p;
+      uint8_t *mra = NULL;
 
       UNPACK_24 (op, tag);
       escape_only_p = ip[1] & 0x1;
@@ -1633,7 +1659,7 @@ VM_NAME (scm_thread *thread)
       /* Push the prompt onto the dynamic stack. */
       SYNC_IP ();
       CALL_INTRINSIC (push_prompt, (thread, escape_only_p, SP_REF (tag),
-                                    VP->fp - proc_slot, ip + offset));
+                                    VP->fp - proc_slot, ip + offset, mra));
 
       NEXT (3);
     }

libguile/vm.c

@@ -153,7 +153,7 @@ scm_i_vm_cont_to_frame (SCM cont, struct scm_frame *frame)
   frame->stack_holder = data;
   frame->fp_offset = data->fp_offset;
   frame->sp_offset = data->stack_size;
-  frame->ip = data->ra;
+  frame->ip = data->vra;
 
   return 1;
 }
@@ -161,10 +161,12 @@ scm_i_vm_cont_to_frame (SCM cont, struct scm_frame *frame)
 /* Ideally we could avoid copying the C stack if the continuation root
    is inside VM code, and call/cc was invoked within that same call to
    vm_run.  That's currently not implemented.  */
-SCM
+static SCM
-scm_i_vm_capture_stack (union scm_vm_stack_element *stack_top,
+capture_stack (union scm_vm_stack_element *stack_top,
                union scm_vm_stack_element *fp,
-                        union scm_vm_stack_element *sp, uint32_t *ra,
+               union scm_vm_stack_element *sp,
+               uint32_t *vra,
+               uint8_t *mra,
                scm_t_dynstack *dynstack, uint32_t flags)
 {
   struct scm_vm_cont *p;
@@ -173,7 +175,8 @@ scm_i_vm_capture_stack (union scm_vm_stack_element *stack_top,
   p->stack_size = stack_top - sp;
   p->stack_bottom = scm_gc_malloc (p->stack_size * sizeof (*p->stack_bottom),
                                    "capture_vm_cont");
-  p->ra = ra;
+  p->vra = vra;
+  p->mra = mra;
   p->fp_offset = stack_top - fp;
   memcpy (p->stack_bottom, sp, p->stack_size * sizeof (*p->stack_bottom));
   p->dynstack = dynstack;
@@ -190,7 +193,7 @@ scm_i_capture_current_stack (void)
   thread = SCM_I_CURRENT_THREAD;
   vp = &thread->vm;
 
-  return scm_i_vm_capture_stack (vp->stack_top, vp->fp, vp->sp, vp->ip,
+  return capture_stack (vp->stack_top, vp->fp, vp->sp, vp->ip, NULL,
                         scm_dynstack_capture_all (&thread->dynstack),
                         0);
 }
@@ -1077,20 +1080,20 @@ reinstate_continuation_x (scm_thread *thread, SCM cont)
     vp->sp[n+i].as_scm = SCM_BOOL_F;
   memcpy(vp->sp, argv, n * sizeof (union scm_vm_stack_element));
 
-  vp->ip = cp->ra;
+  vp->ip = cp->vra;
 
-  scm_i_reinstate_continuation (cont);
+  scm_i_reinstate_continuation (cont, cp->mra);
 }
 
 static SCM
-capture_continuation (scm_thread *thread)
+capture_continuation (scm_thread *thread, uint8_t *mra)
 {
   struct scm_vm *vp = &thread->vm;
-  SCM vm_cont =
+  SCM vm_cont = capture_stack (vp->stack_top,
-    scm_i_vm_capture_stack (vp->stack_top,
                                SCM_FRAME_DYNAMIC_LINK (vp->fp),
                                SCM_FRAME_PREVIOUS_SP (vp->fp),
                                SCM_FRAME_VIRTUAL_RETURN_ADDRESS (vp->fp),
+                               SCM_FRAME_MACHINE_RETURN_ADDRESS (vp->fp),
                                scm_dynstack_capture_all (&thread->dynstack),
                                0);
   return scm_i_make_continuation (thread, vm_cont);
@@ -1114,12 +1117,12 @@ compose_continuation_inner (void *data_ptr)
           cp->stack_size * sizeof (*cp->stack_bottom));
 
   vp->fp -= cp->fp_offset;
-  vp->ip = cp->ra;
+  vp->ip = cp->vra;
 
-  return NULL;
+  return cp->mra;
 }
 
-static void
+static uint8_t*
 compose_continuation (scm_thread *thread, SCM cont)
 {
   struct scm_vm *vp = &thread->vm;
@@ -1128,6 +1131,7 @@ compose_continuation (scm_thread *thread, SCM cont)
   struct scm_vm_cont *cp;
   union scm_vm_stack_element *args;
   ptrdiff_t old_fp_offset;
+  uint8_t *mra;
 
   if (SCM_UNLIKELY (! SCM_VM_CONT_REWINDABLE_P (cont)))
     scm_wrong_type_arg_msg (NULL, 0, cont, "resumable continuation");
@@ -1144,7 +1148,7 @@ compose_continuation (scm_thread *thread, SCM cont)
 
   data.vp = vp;
   data.cp = cp;
-  GC_call_with_alloc_lock (compose_continuation_inner, &data);
+  mra = GC_call_with_alloc_lock (compose_continuation_inner, &data);
 
   /* The resumed continuation will expect ARGS on the stack as if from a
      multiple-value return.  */
@@ -1169,6 +1173,8 @@ compose_continuation (scm_thread *thread, SCM cont)
           scm_dynstack_wind_1 (&thread->dynstack, walk);
       }
   }
+
+  return mra;
 }
 
 static int
@@ -1210,6 +1216,7 @@ foreign_call (scm_thread *thread, SCM cif, SCM pointer)
 static SCM
 capture_delimited_continuation (struct scm_vm *vp,
                                 union scm_vm_stack_element *saved_fp,
+                                uint8_t *saved_mra,
                                 jmp_buf *saved_registers,
                                 scm_t_dynstack *dynstack,
                                 jmp_buf *current_registers)
@@ -1243,8 +1250,8 @@ capture_delimited_continuation (struct scm_vm *vp,
   /* 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,
+  vm_cont = capture_stack (base_fp, vp->fp, vp->fp, vp->ip,
-                                    flags);
+                           saved_mra, dynstack, flags);
 
   return scm_i_make_composable_continuation (vm_cont);
 }
@@ -1257,8 +1264,8 @@ scm_i_vm_abort (SCM *tag_and_argv, size_t n)
   abort ();
 }
 
-static void
+static uint8_t *
-abort_to_prompt (scm_thread *thread)
+abort_to_prompt (scm_thread *thread, uint8_t *saved_mra)
 {
   struct scm_vm *vp = &thread->vm;
   scm_t_dynstack *dynstack = &thread->dynstack;
@@ -1268,15 +1275,16 @@ abort_to_prompt (scm_thread *thread)
   scm_t_dynstack_prompt_flags flags;
   ptrdiff_t fp_offset, sp_offset;
   union scm_vm_stack_element *fp, *sp;
-  uint32_t *ip;
+  uint32_t *vra;
+  uint8_t *mra;
   jmp_buf *registers;
 
   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,
+                                     &flags, &fp_offset, &sp_offset,
-                                     &registers);
+                                     &vra, &mra, &registers);
 
   if (!prompt)
     scm_misc_error ("abort", "Abort to unknown prompt", scm_list_1 (tag));
@@ -1292,8 +1300,8 @@ abort_to_prompt (scm_thread *thread)
       scm_t_dynstack *captured;
 
       captured = scm_dynstack_capture (dynstack, SCM_DYNSTACK_NEXT (prompt));
-      cont = capture_delimited_continuation (vp, fp, registers, captured,
+      cont = capture_delimited_continuation (vp, fp, saved_mra, registers,
-                                             thread->vm.registers);
+                                             captured, thread->vm.registers);
     }
 
   /* Unwind.  */
@@ -1313,15 +1321,20 @@ abort_to_prompt (scm_thread *thread)
   /* Restore VM regs */
   vp->fp = fp;
   vp->sp = sp;
-  vp->ip = ip;
+  vp->ip = vra;
 
   /* If there are intervening C frames, then jump over them, making a
      nonlocal exit.  Otherwise fall through and let the VM pick up where
      it left off.  */
   if (thread->vm.registers != registers)
+    {
+      vp->mra_after_abort = mra;
       longjmp (*registers, 1);
     }
 
+  return mra;
+}
+
 static uint32_t *
 get_callee_vcode (scm_thread *thread)
 {
@@ -1422,10 +1435,13 @@ scm_call_n (SCM proc, SCM *argv, size_t nargs)
     resume = setjmp (registers);
     if (SCM_UNLIKELY (resume))
       {
+        uint8_t *mcode = vp->mra_after_abort;
         scm_gc_after_nonlocal_exit ();
         /* Non-local return.  */
         if (vp->trace_level)
           invoke_abort_hook (thread);
+        if (mcode)
+          vp->ip = scm_jit_enter_mcode (thread, mcode);
       }
     else
       vp->ip = get_callee_vcode (thread);

libguile/vm.h

@@ -58,6 +58,7 @@ struct scm_vm {
   SCM overflow_handler_stack;   /* alist of max-stack-size -> thunk */
   SCM hooks[SCM_VM_NUM_HOOKS];	/* hooks */
   jmp_buf *registers;           /* registers captured at latest vm entry  */
+  uint8_t *mra_after_abort;     /* mra to resume after nonlocal exit, or NULL */
   int engine;                   /* which vm engine we're using */
 };
 
@@ -90,7 +91,9 @@ SCM_INTERNAL void scm_i_vm_free_stack (struct scm_vm *vp);
 
 struct scm_vm_cont {
   /* IP of newest frame.  */
-  uint32_t *ra;
+  uint32_t *vra;
+  /* Machine code corresponding to IP.  */
+  uint8_t *mra;
   /* Offset of FP of newest frame, relative to stack top.  */
   ptrdiff_t fp_offset;
   /* Besides being the stack size, this is also the offset of the SP of
@@ -114,12 +117,6 @@ SCM_API SCM scm_load_compiled_with_vm (SCM file);
 
 SCM_INTERNAL SCM scm_i_call_with_current_continuation (SCM proc);
 SCM_INTERNAL SCM scm_i_capture_current_stack (void);
-SCM_INTERNAL SCM scm_i_vm_capture_stack (union scm_vm_stack_element *stack_top,
-                                         union scm_vm_stack_element *fp,
-                                         union scm_vm_stack_element *sp,
-                                         uint32_t *ra,
-                                         scm_t_dynstack *dynstack,
-                                         uint32_t flags);
 SCM_INTERNAL void scm_i_vm_abort (SCM *tag_and_argv, size_t n) SCM_NORETURN;
 SCM_INTERNAL int scm_i_vm_cont_to_frame (SCM cont, struct scm_frame *frame);
 SCM_INTERNAL void scm_i_vm_cont_print (SCM x, SCM port,