ARM: Remove a bunch of spilled scopes. Still a lot to go.

src/arm/jump-target-arm.cc

Index: src/arm/jump-target-arm.cc
===================================================================
--- src/arm/jump-target-arm.cc	(revision 4863)
+++ src/arm/jump-target-arm.cc	(working copy)
@@ -61,9 +61,17 @@
   } else {
     // Clone the current frame to use as the expected one at the target.
     set_entry_frame(cgen()->frame());
+    // Zap the fall-through frame since the jump was unconditional.
     RegisterFile empty;
     cgen()->SetFrame(NULL, &empty);
   }
+  if (entry_label_.is_bound()) {
+    // You can't jump backwards to an already bound label unless you admitted
+    // up front that this was a bidirectional jump target.  Bidirectional jump
+    // targets will zap their type info when bound in case some later virtual
+    // frame with less precise type info branches to them.
+    ASSERT(direction_ != FORWARD_ONLY);
+  }
   __ jmp(&entry_label_);
 }
 
@@ -83,6 +91,13 @@
     // Clone the current frame to use as the expected one at the target.
     set_entry_frame(cgen()->frame());
   }
+  if (entry_label_.is_bound()) {
+    // You can't branch backwards to an already bound label unless you admitted
+    // up front that this was a bidirectional jump target.  Bidirectional jump
+    // targets will zap their type info when bound in case some later virtual
+    // frame with less precise type info branches to them.
+    ASSERT(direction_ != FORWARD_ONLY);
+  }
   __ b(cc, &entry_label_);
   if (cc == al) {
     cgen()->DeleteFrame();
@@ -121,6 +136,7 @@
   ASSERT(!cgen()->has_valid_frame() || cgen()->HasValidEntryRegisters());
 
   if (cgen()->has_valid_frame()) {
+    if (direction_ != FORWARD_ONLY) cgen()->frame()->ForgetTypeInfo();
     // If there is a current frame we can use it on the fall through.
     if (!entry_frame_set_) {
       entry_frame_ = *cgen()->frame();