diff src/share/vm/opto/rootnode.cpp @ 0:a61af66fc99e jdk7-b24

Initial load
author duke
date Sat, 01 Dec 2007 00:00:00 +0000
parents
children c18cbe5936b8
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--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/share/vm/opto/rootnode.cpp	Sat Dec 01 00:00:00 2007 +0000
@@ -0,0 +1,81 @@
+/*
+ * Copyright 1997-2005 Sun Microsystems, Inc.  All Rights Reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ *
+ */
+
+#include "incls/_precompiled.incl"
+#include "incls/_rootnode.cpp.incl"
+
+//------------------------------Ideal------------------------------------------
+// Remove dead inputs
+Node *RootNode::Ideal(PhaseGVN *phase, bool can_reshape) {
+  for( uint i = 1; i < req(); i++ ) { // For all inputs
+    // Check for and remove dead inputs
+    if( phase->type(in(i)) == Type::TOP ) {
+      del_req(i--);             // Delete TOP inputs
+    }
+  }
+
+  // I used to do tail-splitting in the Ideal graph here, but it does not
+  // work.  The tail-splitting forces values live into the Return to be
+  // ready at a point which dominates the split returns.  This forces Stores
+  // to be hoisted high.  The "proper" fix would be to split Stores down
+  // each path, but this makes the split unprofitable.  If we want to do this
+  // optimization, it needs to be done after allocation so we can count all
+  // the instructions needing to be cloned in the cost metric.
+
+  // There used to be a spoof here for caffeine marks which completely
+  // eliminated very simple self-recursion recursions, but it's not worth it.
+  // Deep inlining of self-calls gets nearly all of the same benefits.
+  // If we want to get the rest of the win later, we should pattern match
+  // simple recursive call trees to closed-form solutions.
+
+  return NULL;                  // No further opportunities exposed
+}
+
+//=============================================================================
+HaltNode::HaltNode( Node *ctrl, Node *frameptr ) : Node(TypeFunc::Parms) {
+  Node* top = Compile::current()->top();
+  init_req(TypeFunc::Control,  ctrl        );
+  init_req(TypeFunc::I_O,      top);
+  init_req(TypeFunc::Memory,   top);
+  init_req(TypeFunc::FramePtr, frameptr    );
+  init_req(TypeFunc::ReturnAdr,top);
+}
+
+const Type *HaltNode::bottom_type() const { return Type::BOTTOM; }
+
+//------------------------------Ideal------------------------------------------
+Node *HaltNode::Ideal(PhaseGVN *phase, bool can_reshape) {
+  return remove_dead_region(phase, can_reshape) ? this : NULL;
+}
+
+//------------------------------Value------------------------------------------
+const Type *HaltNode::Value( PhaseTransform *phase ) const {
+  return ( phase->type(in(TypeFunc::Control)) == Type::TOP)
+    ? Type::TOP
+    : Type::BOTTOM;
+}
+
+const RegMask &HaltNode::out_RegMask() const {
+  return RegMask::Empty;
+}