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

src/arm/jump-target-arm.cc

 // Copyright 2008 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 43 matching lines @@
       // If we already bound and generated code at the destination then it
       // is too late to ask for less optimistic type assumptions.
       ASSERT(entry_frame_.IsCompatibleWith(cgen()->frame()));
     }
     // There already a frame expectation at the target.
     cgen()->frame()->MergeTo(&entry_frame_);
     cgen()->DeleteFrame();
   } 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_);
 }
 
 
 void JumpTarget::DoBranch(Condition cc, Hint ignored) {
   ASSERT(cgen()->has_valid_frame());
 
   if (entry_frame_set_) {
     if (entry_label_.is_bound()) {
       // If we already bound and generated code at the destination then it
       // is too late to ask for less optimistic type assumptions.
       ASSERT(entry_frame_.IsCompatibleWith(cgen()->frame()));
     }
     // We have an expected frame to merge to on the backward edge.
     cgen()->frame()->MergeTo(&entry_frame_, cc);
   } else {
     // 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();
   }
 }
 
 
 void JumpTarget::Call() {
   // Call is used to push the address of the catch block on the stack as
   // a return address when compiling try/catch and try/finally.  We
@@ skipping 18 matching lines @@
 
 
 void JumpTarget::DoBind() {
   ASSERT(!is_bound());
 
   // Live non-frame registers are not allowed at the start of a basic
   // block.
   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();
       entry_frame_set_ = true;
     } else {
       cgen()->frame()->MergeTo(&entry_frame_);
     }
   } else {
     // If there is no current frame we must have an entry frame which we can
     // copy.
     ASSERT(entry_frame_set_);
     RegisterFile empty;
     cgen()->SetFrame(new VirtualFrame(&entry_frame_), &empty);
   }
 
   __ bind(&entry_label_);
 }
 
 
 #undef __
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_ARM