Eliminate most of the jump target jumping, branching, and binding...

src/ia32/jump-target-ia32.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 344 matching lines @@
     // for possible reuse as a backward merge block.
     RegisterFile empty;
     cgen()->SetFrame(new VirtualFrame(reaching_frames_[0]), &empty);
     __ bind(&merge_labels_[0]);
     cgen()->frame()->MergeTo(entry_frame_);
   }
 
   __ bind(&entry_label_);
 }
 
+
+void BreakTarget::Jump() {
+  // Drop leftover statement state from the frame before merging, without
+  // emitting code.
+  ASSERT(cgen()->has_valid_frame());
+  int count = cgen()->frame()->height() - expected_height_;
+  cgen()->frame()->ForgetElements(count);
+  DoJump();
+}
+
+
+void BreakTarget::Jump(Result* arg) {
+  // Drop leftover statement state from the frame before merging, without
+  // emitting code.
+  ASSERT(cgen()->has_valid_frame());
+  int count = cgen()->frame()->height() - expected_height_;
+  cgen()->frame()->ForgetElements(count);
+  cgen()->frame()->Push(arg);
+  DoJump();
+}
+
+
+void BreakTarget::Bind() {
+#ifdef DEBUG
+  // All the forward-reaching frames should have been adjusted at the
+  // jumps to this target.
+  for (int i = 0; i < reaching_frames_.length(); i++) {
+    ASSERT(reaching_frames_[i] == NULL ||
+           reaching_frames_[i]->height() == expected_height_);
+  }
+#endif
+  // Drop leftover statement state from the frame before merging, even on
+  // the fall through.  This is so we can bind the return target with state
+  // on the frame.
+  if (cgen()->has_valid_frame()) {
+    int count = cgen()->frame()->height() - expected_height_;
+    cgen()->frame()->ForgetElements(count);
+  }
+  DoBind();
+}
+
+
+void BreakTarget::Bind(Result* arg) {
+#ifdef DEBUG
+  // All the forward-reaching frames should have been adjusted at the
+  // jumps to this target.
+  for (int i = 0; i < reaching_frames_.length(); i++) {
+    ASSERT(reaching_frames_[i] == NULL ||
+           reaching_frames_[i]->height() == expected_height_ + 1);
+  }
+#endif
+  // Drop leftover statement state from the frame before merging, even on
+  // the fall through.  This is so we can bind the return target with state
+  // on the frame.
+  if (cgen()->has_valid_frame()) {
+    int count = cgen()->frame()->height() - expected_height_;
+    cgen()->frame()->ForgetElements(count);
+    cgen()->frame()->Push(arg);
+  }
+  DoBind();
+  *arg = cgen()->frame()->Pop();
+}
+
+
 #undef __
 
 
 } }  // namespace v8::internal