* vm_core.h: remove VM_FRAME_MAGIC_FINISH (finish frame type).

  Before this commit:
  `finish frame' was place holder which indicates that VM loop
  needs to return function.
  If a C method calls a Ruby methods (a method written by Ruby),
  then VM loop will be (re-)invoked.  When the Ruby method returns,
  then also VM loop should be escaped.  `finish frame' has only
  one instruction `finish', which returns VM loop function.
  VM loop function executes `finish' instruction, then VM loop
  function returns itself.
  With such mechanism, `leave' instruction (which returns one
  frame from current scope) doesn't need to check that this `leave'
  should also return from VM loop function.
  Strictly, one branch can be removed from `leave' instructon.
  Consideration:
  However, pushing the `finish frame' needs costs because
  it needs several memory accesses.  The number of pushing
  `finish frame' is greater than I had assumed.  Of course,
  pushing `finish frame' consumes additional control frame.
  Moreover, recent processors has good branch prediction,
  with which we can ignore such trivial checking.
  After this commit:
  Finally, I decide to remove `finish frame' and `finish'
  instruction.  Some parts of VM depend on `finish frame',
  so the new frame flag VM_FRAME_FLAG_FINISH is introduced.
  If this frame should escape from VM function loop, then
  the result of VM_FRAME_TYPE_FINISH_P(cfp) is true.
  `leave' instruction checks this flag every time.
  I measured performance on it.  However on my environments,
  it improves some benchmarks and slows some benchmarks down.
  Maybe it is because of C compiler optimization parameters.
  I'll re-visit here if this cause problems.
* insns.def (leave, finish): remove finish instruction.
* vm.c, vm_eval.c, vm_exec.c, vm_backtrace.c, vm_dump.c:
  apply above changes.



git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@36099 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 8 insertions, 13 deletions

diff --git a/vm_dump.c b/vm_dump.c
index d38f114b86..68b380b49c 100644
--- a/vm_dump.c
+++ b/vm_dump.c
@@ -32,7 +32,6 @@ control_frame_dump(rb_thread_t *th, rb_control_frame_t *cfp)
     char ep_in_heap = ' ';
     char posbuf[MAX_POSBUF+1];
     int line = 0;
-    int nopos = 0;
 
     const char *magic, *iseq_name = "-", *selfstr = "-", *biseq_name = "-";
     VALUE tmp;
@@ -62,10 +61,6 @@ control_frame_dump(rb_thread_t *th, rb_control_frame_t *cfp)
       case VM_FRAME_MAGIC_BLOCK:
 	magic = "BLOCK";
 	break;
-      case VM_FRAME_MAGIC_FINISH:
-	magic = "FINISH";
-	nopos = 1;
-	break;
       case VM_FRAME_MAGIC_CFUNC:
 	magic = "CFUNC";
 	break;
@@ -97,10 +92,7 @@ control_frame_dump(rb_thread_t *th, rb_control_frame_t *cfp)
 	selfstr = "";
     }
 
-    if (nopos) {
-	/* no name */
-    }
-    else if (cfp->iseq != 0) {
+    if (cfp->iseq != 0) {
 	if (RUBY_VM_IFUNC_P(cfp->iseq)) {
 	    iseq_name = "<ifunc>";
 	}
@@ -130,9 +122,12 @@ control_frame_dump(rb_thread_t *th, rb_control_frame_t *cfp)
     fprintf(stderr, "s:%04"PRIdPTRDIFF" b:%04"PRIdPTRDIFF" ", (cfp->sp - th->stack), bp);
     fprintf(stderr, ep_in_heap == ' ' ? "e:%06"PRIdPTRDIFF" " : "e:%06"PRIxPTRDIFF" ", ep % 10000);
     fprintf(stderr, "%-6s", magic);
-    if (line && !nopos) {
+    if (line) {
 	fprintf(stderr, " %s", posbuf);
     }
+    if (VM_FRAME_TYPE_FINISH_P(cfp)) {
+	fprintf(stderr, " [FINISH]");
+    }
     if (0) {
 	fprintf(stderr, "              \t");
 	fprintf(stderr, "iseq: %-24s ", iseq_name);
@@ -302,8 +297,8 @@ vm_stack_dump_each(rb_thread_t *th, rb_control_frame_t *cfp)
 		    (ptr - th->stack));
 	}
     }
-    else if (VM_FRAME_TYPE(cfp) == VM_FRAME_MAGIC_FINISH) {
-	if ((th)->stack + (th)->stack_size > (VALUE *)(cfp + 2)) {
+    else if (VM_FRAME_TYPE_FINISH_P(VM_FRAME_TYPE(cfp))) {
+	if ((th)->stack + (th)->stack_size > (VALUE *)(cfp + 1)) {
 	    vm_stack_dump_each(th, cfp + 1);
 	}
 	else {
@@ -350,7 +345,7 @@ rb_vmdebug_debug_print_pre(rb_thread_t *th, rb_control_frame_t *cfp)
 {
     rb_iseq_t *iseq = cfp->iseq;
 
-    if (iseq != 0 && VM_FRAME_TYPE(cfp) != VM_FRAME_MAGIC_FINISH) {
+    if (iseq != 0 && !VM_FRAME_TYPE_FINISH_P(cfp)) {
 	VALUE *seq = iseq->iseq;
 	ptrdiff_t pc = cfp->pc - iseq->iseq_encoded;
 	int i;