less overhead for handling interrupts in the vm

* libguile/__scm.h (SCM_ASYNC_TICK): Add some branch prediction.
  (SCM_ASYNC_TICK_WITH_CODE): New helper for when BUILDING_LIBGUILE,
  runs code only if we're going to call async_click().
* libguile/vm-engine.h (VM_HANDLE_INTERRUPTS): New helper, uses
  SCM_ASYNC_TICK_WITH_CODE to only save regs if we'll handle an
  interrupt.
* libguile/vm-i-system.c (call, goto/args, return): use
  VM_HANDLE_INTERRUPTS.

diff --git a/libguile/__scm.h b/libguile/__scm.h
index b4e1bd9..93f6662 100644 (file)
--- a/libguile/__scm.h
+++ b/libguile/__scm.h
@@ -498,12 +498,24 @@ SCM_API void scm_async_tick (void);
 #ifdef BUILDING_LIBGUILE
 
 /* FIXME: should change names */
-# define SCM_ASYNC_TICK                                        \
-    do                                                 \
-      {                                                        \
-       if (SCM_I_CURRENT_THREAD->pending_asyncs)       \
-         scm_async_click ();                           \
-      }                                                        \
+# define SCM_ASYNC_TICK                                                 \
+    do                                                                  \
+      {                                                                 \
+       if (SCM_UNLIKELY (SCM_I_CURRENT_THREAD->pending_asyncs))        \
+         scm_async_click ();                                           \
+      }                                                                 \
+    while (0)
+
+/* SCM_ASYNC_TICK_WITH_CODE is only available to Guile itself */
+# define SCM_ASYNC_TICK_WITH_CODE(stmt)                                 \
+    do                                                                  \
+      {                                                                 \
+       if (SCM_UNLIKELY (SCM_I_CURRENT_THREAD->pending_asyncs))        \
+         {                                                             \
+            stmt;                                                       \
+            scm_async_click ();                                         \
+          }                                                             \
+      }                                                                 \
     while (0)
 
 #else /* !BUILDING_LIBGUILE */

diff --git a/libguile/vm-engine.h b/libguile/vm-engine.h
index ebe40b2..838ed20 100644 (file)
--- a/libguile/vm-engine.h
+++ b/libguile/vm-engine.h
@@ -228,6 +228,9 @@
 #define EXIT_HOOK()    RUN_HOOK (SCM_VM_EXIT_HOOK)
 #define RETURN_HOOK()  RUN_HOOK (SCM_VM_RETURN_HOOK)
 
+#define VM_HANDLE_INTERRUPTS                     \
+  SCM_ASYNC_TICK_WITH_CODE (SYNC_REGISTER ())
+
 \f
 /*
  * Stack operation

diff --git a/libguile/vm-i-system.c b/libguile/vm-i-system.c
index 7de11e7..8eaf59c 100644 (file)
--- a/libguile/vm-i-system.c
+++ b/libguile/vm-i-system.c
@@ -747,8 +747,7 @@ VM_DEFINE_INSTRUCTION (54, call, "call", 1, -1, 1)
  vm_call:
   x = sp[-nargs];
 
-  SYNC_REGISTER ();
-  SCM_TICK;    /* allow interrupt here */
+  VM_HANDLE_INTERRUPTS;
 
   /*
    * Subprogram call
@@ -813,8 +812,7 @@ VM_DEFINE_INSTRUCTION (55, goto_args, "goto/args", 1, -1, 1)
  vm_goto_args:
   x = sp[-nargs];
 
-  SYNC_REGISTER ();
-  SCM_TICK;    /* allow interrupt here */
+  VM_HANDLE_INTERRUPTS;
 
   /*
    * Tail call
@@ -1085,8 +1083,9 @@ VM_DEFINE_INSTRUCTION (63, return, "return", 0, 1, 1)
  vm_return:
   EXIT_HOOK ();
   RETURN_HOOK ();
-  SYNC_REGISTER ();
-  SCM_TICK;    /* allow interrupt here */
+
+  VM_HANDLE_INTERRUPTS;
+
   {
     SCM ret;