8005976: Break out AccessSpecializer into one pass before CodeGenerator instead of iterative applications from CodeGenerator

Summary: Now scope and slot information is guaranteed to be fixed AND NOT CHANGE before CodeGeneration. We want to keep it that way to build future type specializations and bring all type work out of CodeGenerator.
Reviewed-by: attila, hannesw

13 files changed, 198 insertions, 148 deletions

diff --git a/bin/dump_octane_code.sh b/bin/dump_octane_code.sh
new file mode 100644
index 00000000..d24ab2ce
--- /dev/null
+++ b/bin/dump_octane_code.sh
@@ -0,0 +1,53 @@
+#!/bin/bash
+# Copyright (c) 2010, 2013, Oracle and/or its affiliates. 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+# or visit www.oracle.com if you need additional information or have any
+# questions.
+#
+
+#
+# The purpose of this script is to provide a large amount of IR/bytecode from a known
+# application to be diffed against the same output with a different Nashorn version.
+# That way we can quickly detect if a seemingly minute change modifies a lot of code,
+# which it most likely shouldn't. One example of this was when AccessSpecializer was
+# moved into Lower the first time, it worked fine, but as a lot of Scope information
+# at the time was finalized further down the code pipeline it did a lot fewer callsite
+# specializations. This would have been immediately detected with a before and after 
+# diff using the output from this script.
+#
+
+ITERS=$1
+if [ -z $ITERS ]; then 
+    ITERS=7
+fi
+NASHORN_JAR=dist/nashorn.jar
+JVM_FLAGS="-ea -esa -server -jar ${NASHORN_JAR}"
+
+BENCHMARKS=( "box2d.js" "code-load.js" "crypto.js" "deltablue.js" "earley-boyer.js" "gbemu.js" "mandreel.js" "navier-stokes.js" "pdfjs.js" "raytrace.js" "regexp.js" "richards.js" "splay.js" )
+
+for BENCHMARK in "${BENCHMARKS[@]}"
+do     
+    echo "START: ${BENCHMARK}"
+    CMD="${JAVA_HOME}/bin/java ${JVM_FLAGS} -co --print-lower-parse test/script/external/octane/${BENCHMARK}"
+    $CMD
+    echo "END: ${BENCHMARK}"
+    echo ""
+done
+
+echo "Done"
diff --git a/bin/verbose_octane.sh b/bin/verbose_octane.sh
index 3e453adb..e70e9d48 100644
--- a/bin/verbose_octane.sh
+++ b/bin/verbose_octane.sh
@@ -26,18 +26,18 @@ if [ -z $ITERS ]; then
     ITERS=7
 fi
 NASHORN_JAR=dist/nashorn.jar
-JVM_FLAGS="-XX:+UnlockDiagnosticVMOptions -Dnashorn.unstable.relink.threshold=8 -Xms2G -Xmx2G -XX:-TieredCompilation -server -jar ${NASHORN_JAR}"
+JVM_FLAGS="-XX:+UnlockDiagnosticVMOptions -Dnashorn.unstable.relink.threshold=8 -Xms2G -Xmx2G -XX:+TieredCompilation -server -jar ${NASHORN_JAR}"
 JVM_FLAGS7="-Xbootclasspath/p:${NASHORN_JAR} ${JVM_FLAGS}"
 OCTANE_ARGS="--verbose --iterations ${ITERS}"
 
-BENCHMARKS=( "box2d.js" "code-load.js" "crypto.js" "deltablue.js" "earley-boyer.js" "gbemu.js" "navier-stokes.js" "raytrace.js" "regexp.js" "richards.js" "splay.js" )
+BENCHMARKS=( "box2d.js" "code-load.js" "crypto.js" "deltablue.js" "earley-boyer.js" "gbemu.js" "navier-stokes.js" "pdfjs.js" "raytrace.js" "regexp.js" "richards.js" "splay.js" )
 # TODO mandreel.js has metaspace issues
 
 if [ ! -z $JAVA7_HOME ]; then	
     echo "running ${ITERS} iterations with java7 using JAVA_HOME=${JAVA7_HOME}..."
     for BENCHMARK in "${BENCHMARKS[@]}"
     do 
-	CMD="${JAVA8_HOME}/bin/java ${JVM_FLAGS} test/script/basic/run-octane.js -- test/script/external/octane/${BENCHMARK} ${OCTANE_ARGS}"
+	CMD="${JAVA7_HOME}/bin/java ${JVM_FLAGS} test/script/basic/run-octane.js -- test/script/external/octane/${BENCHMARK} ${OCTANE_ARGS}"
 	$CMD
     done
 else
@@ -52,7 +52,7 @@ if [ ! -z $JAVA8_HOME ]; then
 	$CMD
     done
 else 
-    echo "no JAVA8_HOME set"
+    echo "no JAVA8_HOME set."
 fi
 
 echo "Done"
diff --git a/docs/DEVELOPER_README b/docs/DEVELOPER_README
index a4859701..55c41010 100644
--- a/docs/DEVELOPER_README
+++ b/docs/DEVELOPER_README
@@ -23,6 +23,13 @@ has a default value (currently 8 relinks) for this property if it
 is not explicitly set.
 
 
+SYSTEM PROPERTY: -Dnashorn.compiler.split.threshold=x
+
+This will change the node weight that requires a subgraph of the IR to
+be split into several classes in order not to run out of bytecode space.
+The default value is 0x8000 (32768).
+
+
 SYSTEM PROPERTY: -Dnashorn.callsiteaccess.debug
 
 See the description of the access logger below. This flag is
@@ -451,4 +458,4 @@ the level is set to finest, it will also trace every AccessorProperty
 getter and setter in the program, show arguments, return values
 etc. It will also show the internal representation of respective field
 (Object in the normal case, unless running with the dual field
-representation)
\ No newline at end of file
+representation)
diff --git a/src/jdk/nashorn/internal/codegen/AccessSpecializer.java b/src/jdk/nashorn/internal/codegen/AccessSpecializer.java
index 6db7e6ec..e6eee814 100644
--- a/src/jdk/nashorn/internal/codegen/AccessSpecializer.java
+++ b/src/jdk/nashorn/internal/codegen/AccessSpecializer.java
@@ -31,7 +31,6 @@ import jdk.nashorn.internal.ir.AccessNode;
 import jdk.nashorn.internal.ir.Assignment;
 import jdk.nashorn.internal.ir.BinaryNode;
 import jdk.nashorn.internal.ir.CallNode;
-import jdk.nashorn.internal.ir.FunctionNode;
 import jdk.nashorn.internal.ir.IdentNode;
 import jdk.nashorn.internal.ir.IndexNode;
 import jdk.nashorn.internal.ir.Node;
@@ -64,28 +63,13 @@ import jdk.nashorn.internal.runtime.DebugLogger;
  * @see TypeOverride
  */
 
-final class AccessSpecializer extends NodeOperatorVisitor implements Transform {
+final class AccessSpecializer extends NodeOperatorVisitor {
     /** Debug logger for access specialization. Enable it with --log=access:level
-        or -Dnashorn.specializations.debug */
+        or -Dnashorn.callsiteaccess.debug */
     private static final DebugLogger LOG   = new DebugLogger("access", "nashorn.callsiteaccess.debug");
     private static final boolean     DEBUG = LOG.isEnabled();
 
     @Override
-    public Node enter(final FunctionNode node) {
-        if (node.isTransformApplied(AccessSpecializer.class)) {
-            return null;
-        }
-
-        return node;
-    }
-
-    @Override
-    public Node leave(final FunctionNode node) {
-        node.registerTransform(AccessSpecializer.class);
-        return node;
-    }
-
-    @Override
     public Node leave(final VarNode varNode) {
         if (varNode.isAssignment()) {
             return leaveAssign(varNode);
@@ -191,7 +175,7 @@ final class AccessSpecializer extends NodeOperatorVisitor implements Transform {
              * getter/setter is selected, which will do the conversion for us
              */
             changeType(rhs, castTo);
-            fine("*** cast: converting " + debugNode(unaryNode) + " to " + debugNode(rhs));
+            LOG.fine("*** cast: converting " + debugNode(unaryNode) + " to " + debugNode(rhs));
 
             return rhs;
         }
@@ -270,17 +254,17 @@ final class AccessSpecializer extends NodeOperatorVisitor implements Transform {
         final Symbol lhsSymbol = lhs.getSymbol();
 
         if (lhsSymbol.hasSlot() && !lhsSymbol.isScope()) {
-            finest(lhs.getSymbol() + " has slot!");
+            LOG.finest(lhs.getSymbol() + " has slot!");
             if (!lhs.getType().isEquivalentTo(rhs.getType())) {
-                finest("\tslot assignment: " +lhs.getType()+ " " +rhs.getType() + " " + debugNode(node));
+                LOG.finest("\tslot assignment: " +lhs.getType()+ " " +rhs.getType() + " " + debugNode(node));
 
                 final Node c = convert(rhs);
                 c.setSymbol(lhsSymbol);
                 ((Assignment<?>)node).setAssignmentSource(c);
 
-                fine("*** slot assignment turned to : " + debugNode(node));
+                LOG.fine("*** slot assignment turned to : " + debugNode(node));
             } else {
-                finest("aborted - type equivalence between lhs and rhs");
+                LOG.finest("aborted - type equivalence between lhs and rhs");
             }
 
             return node;
@@ -310,10 +294,10 @@ final class AccessSpecializer extends NodeOperatorVisitor implements Transform {
 
         // If castTo is wider than widestOperationType, castTo can be further slowed down
         final Type widestOperationType = node.getWidestOperationType();
-        finest("node wants to be " + castTo + " and its widest operation is " + widestOperationType);
+        LOG.finest("node wants to be " + castTo + " and its widest operation is " + widestOperationType);
 
         if (widestOperationType != castTo && Type.widest(castTo, widestOperationType) == castTo) {
-            info("###" + node + " castTo was " + castTo + " but could be downgraded to " + node.getWidestOperationType());
+            LOG.info("###" + node + " castTo was " + castTo + " but could be downgraded to " + node.getWidestOperationType());
             castTo = node.getWidestOperationType();
             if (rhs instanceof TypeOverride) {
                 changeType(rhs, castTo);
@@ -331,16 +315,16 @@ final class AccessSpecializer extends NodeOperatorVisitor implements Transform {
         // We only specialize for numerics, not for booleans.
         if (isSupportedCallSiteType(castTo)) {
             if (rhs.getType() != castTo) {
-                finest("cast was necessary, abort: " + node + " " + rhs.getType() + " != " + castTo);
+                LOG.finest("cast was necessary, abort: " + node + " " + rhs.getType() + " != " + castTo);
                 return node;
             }
 
-            finest("assign: " + debugNode(node));
+            LOG.finest("assign: " + debugNode(node));
 
             changeTypeInAssignment(lhs, castTo);
             ((Assignment<?>)node).setAssignmentSource(rhs);
 
-            info("### modified to " + debugNode(node) + " (given type override " + castTo + ")");
+            LOG.info("### modified to " + debugNode(node) + " (given type override " + castTo + ")");
 
             propagateResultType(node, castTo);
         }
@@ -352,9 +336,9 @@ final class AccessSpecializer extends NodeOperatorVisitor implements Transform {
         //warning! this CANNOT be done for non temporaries as they are used in other computations
         if (isSupportedCallSiteType(type)) {
             if (node.getSymbol().isTemp()) {
-                finest("changing temporary type: " + debugNode(node) + " to " + type);
+                LOG.finest("changing temporary type: " + debugNode(node) + " to " + type);
                 node.getSymbol().setTypeOverride(type);
-                info("### node modified to " + debugNode(node) + " (given type override " + type + ")");
+                LOG.info("### node modified to " + debugNode(node) + " (given type override " + type + ")");
             }
         }
         return node;
@@ -362,7 +346,7 @@ final class AccessSpecializer extends NodeOperatorVisitor implements Transform {
 
     private static void changeTypeInAssignment(final Node dest, final Type newType) {
         if (changeType(dest, newType)) {
-            finest("changed assignment " + dest + " " + dest.getSymbol());
+            LOG.finest("changed assignment " + dest + " " + dest.getSymbol());
             assert !newType.isObject();
 
             final HashSet<Node> exclude = new HashSet<>();
@@ -370,7 +354,7 @@ final class AccessSpecializer extends NodeOperatorVisitor implements Transform {
             dest.accept(new NodeVisitor() {
 
                 private void setCanBePrimitive(final Symbol symbol) {
-                    fine("*** can be primitive symbol " + symbol + " " + Debug.id(symbol));
+                    LOG.fine("*** can be primitive symbol " + symbol + " " + Debug.id(symbol));
                     symbol.setCanBePrimitive(newType);
                 }
 
@@ -412,17 +396,4 @@ final class AccessSpecializer extends NodeOperatorVisitor implements Transform {
         }
         return "";
     }
-
-    private static void info(final String str) {
-        LOG.info(str);
-    }
-
-    private static void fine(final String str) {
-        LOG.fine(str);
-    }
-
-    private static void finest(final String str) {
-        LOG.finest(str);
-    }
-
 }
diff --git a/src/jdk/nashorn/internal/codegen/CodeGenerator.java b/src/jdk/nashorn/internal/codegen/CodeGenerator.java
index 444c9839..b673d4cf 100644
--- a/src/jdk/nashorn/internal/codegen/CodeGenerator.java
+++ b/src/jdk/nashorn/internal/codegen/CodeGenerator.java
@@ -845,16 +845,12 @@ public final class CodeGenerator extends NodeOperatorVisitor {
         return null;
     }
 
-    private void initLocals(final Block block) {
-        initLocals(block, null);
-    }
-
     /**
      * Initialize the slots in a frame to undefined.
      *
      * @param block block with local vars.
      */
-    private void initLocals(final Block block, final AccessSpecializer accessSpecializer) {
+    private void initLocals(final Block block) {
         final FunctionNode function       = block.getFunction();
         final boolean      isFunctionNode = block == function;
 
@@ -885,14 +881,6 @@ public final class CodeGenerator extends NodeOperatorVisitor {
             final List<String> nameList = new ArrayList<>();
             final List<Symbol> locals   = new ArrayList<>();
 
-            // note that in the case of a varargs vector the arguments in the vector should NOT have local slots
-            // this was a bug: see NASHORN-21
-            if (isVarArg) {
-                for (final IdentNode param : function.getParameters()) {
-                    param.getSymbol().setNeedsSlot(false);
-                }
-            }
-
             // If there are variable arguments, we need to load them (functions only).
             if (isFunctionNode && isVarArg) {
                 method.loadVarArgs();
@@ -915,8 +903,8 @@ public final class CodeGenerator extends NodeOperatorVisitor {
                     nameList.add(symbol.getName());
                     newSymbols.add(symbol);
                     values.add(null);
-                    symbol.setIsScope();
-                    symbol.setNeedsSlot(false);
+                    assert symbol.isScope()   : "scope for " + symbol + " should have been set in Lower already " + function.getName();
+                    assert !symbol.hasSlot()  : "slot for " + symbol + " should have been removed in Lower already" + function.getName();
                 } else if (symbol.isVar()) {
                     assert symbol.hasSlot() : symbol + " should have a slot only, no scope";
                     locals.add(symbol);
@@ -924,10 +912,8 @@ public final class CodeGenerator extends NodeOperatorVisitor {
                     nameList.add(symbol.getName());
                     newSymbols.add(symbol);
                     values.add(isVarArg ? null : symbol);
-                    symbol.setIsScope();
-                    if (isVarArg) {
-                        symbol.setNeedsSlot(false);
-                    }
+                    assert symbol.isScope()   : "scope for " + symbol + " should have been set in Lower already " + function.getName() + " varsInScope="+varsInScope+" isVarArg="+isVarArg+" symbol.isScope()=" + symbol.isScope();
+                    assert !(isVarArg && symbol.hasSlot())  : "slot for " + symbol + " should have been removed in Lower already " + function.getName();
                 }
             }
 
@@ -941,10 +927,6 @@ public final class CodeGenerator extends NodeOperatorVisitor {
                 initScope();
             }
 
-            if (accessSpecializer != null) {
-                ((FunctionNode)block).accept(accessSpecializer);
-            }
-
             /*
              * Create a new object based on the symbols and values, generate
              * bootstrap code for object
@@ -1001,7 +983,7 @@ public final class CodeGenerator extends NodeOperatorVisitor {
         method.begin();
         method.label(functionNode.getEntryLabel());
 
-        initLocals(functionNode, new AccessSpecializer());
+        initLocals(functionNode);
 
         return functionNode;
     }
diff --git a/src/jdk/nashorn/internal/codegen/Compiler.java b/src/jdk/nashorn/internal/codegen/Compiler.java
index dad79aab..8d02f611 100644
--- a/src/jdk/nashorn/internal/codegen/Compiler.java
+++ b/src/jdk/nashorn/internal/codegen/Compiler.java
@@ -298,6 +298,8 @@ public final class Compiler {
 
         /** do we need to parse source? */
         if (!state.contains(State.PARSED)) {
+            LOG.info("Parsing '" + source + "'");
+
             assert this.functionNode == null;
             this.functionNode = new Parser(this, strict).parse(RUN_SCRIPT.tag());
 
@@ -338,6 +340,7 @@ public final class Compiler {
 
             if (!state.contains(State.LOWERED)) {
                 debugPrintAST();
+                LOG.info("Lowering '" + functionNode.getName() + "'");
                 functionNode.accept(new Lower(this));
                 state.add(State.LOWERED);
 
@@ -352,6 +355,7 @@ public final class Compiler {
             // and add script code last this class may end up slightly larger than others, but reserving one class
             // just for the main script seems wasteful.
             final CompileUnit scriptCompileUnit = addCompileUnit(firstCompileUnitName(), 0l);
+            LOG.info("Splitting '" + functionNode.getName() + "'");
             new Splitter(this, functionNode, scriptCompileUnit).split();
             assert functionNode.getCompileUnit() == scriptCompileUnit;
 
@@ -361,7 +365,14 @@ public final class Compiler {
                 strict = true;
             }
 
+            LOG.info("Adjusting slot and scope information for symbols for '" + functionNode.getName() + "'");
+            functionNode.accept(new Lower.FinalizeSymbols());
+
+            LOG.info("Specializing callsite types for '" + functionNode.getName() + "'");
+            functionNode.accept(new AccessSpecializer());
+
             try {
+                LOG.info("Emitting bytecode for '" + functionNode.getName() + "'");
                 final CodeGenerator codegen = new CodeGenerator(this);
                 functionNode.accept(codegen);
                 codegen.generateScopeCalls();
@@ -408,6 +419,7 @@ public final class Compiler {
             return true;
         } finally {
             strict = oldStrict;
+            LOG.info("Done with '" + functionNode.getName() + "'");
         }
     }
 
diff --git a/src/jdk/nashorn/internal/codegen/Lower.java b/src/jdk/nashorn/internal/codegen/Lower.java
index 0630667d..a19febfb 100644
--- a/src/jdk/nashorn/internal/codegen/Lower.java
+++ b/src/jdk/nashorn/internal/codegen/Lower.java
@@ -916,6 +916,13 @@ final class Lower extends NodeOperatorVisitor {
         } else {
             LOG.info("parameter specialization possible: " + functionNode.getName() + " " + paramSpecializations);
         }
+
+        // parameters should not be slots for a vararg function, make sure this is the case
+        if (functionNode.isVarArg()) {
+            for (final IdentNode param : functionNode.getParameters()) {
+                param.getSymbol().setNeedsSlot(false);
+            }
+        }
     }
 
     private LiteralNode<Undefined> undefined() {
@@ -1086,6 +1093,7 @@ final class Lower extends NodeOperatorVisitor {
 
     @Override
     public Node enter(final FunctionNode functionNode) {
+        LOG.info("START FunctionNode: " + functionNode.getName());
 
         Node initialEvalResult = undefined();
 
@@ -1255,6 +1263,8 @@ final class Lower extends NodeOperatorVisitor {
         functionNode.setIsLowered(true);
         functionNode.popFrame();
 
+        LOG.info("END FunctionNode: " + functionNode.getName());
+
         return null;
     }
 
@@ -1482,9 +1492,9 @@ final class Lower extends NodeOperatorVisitor {
 
     @Override
     public Node enter(final ReferenceNode referenceNode) {
-        final FunctionNode fn = referenceNode.getReference();
-        if (fn != null) {
-            fn.addReferencingParentBlock(getCurrentBlock());
+        final FunctionNode functionNode = referenceNode.getReference();
+        if (functionNode != null) {
+            functionNode.addReferencingParentBlock(getCurrentBlock());
         }
         return referenceNode;
     }
@@ -2869,6 +2879,74 @@ final class Lower extends NodeOperatorVisitor {
     }
 
     /**
+     * A simple node visitor that ensure that scope and slot information is correct.
+     * This is run as a post pass after we know all scope changing information about
+     * the Lowering. This is also called after potential mutations like splitting
+     * have taken place, as splitting forces scope.
+     *
+     * This was previously done on a per functionNode basis in {@link CodeGenerator},
+     * but this is too late for type information to be used in {@link AccessSpecializer}
+     */
+    static class FinalizeSymbols extends NodeVisitor {
+        @Override
+        public Node leave(final Block block) {
+            return updateSymbols(block);
+        }
+
+        @Override
+        public Node leave(final FunctionNode function) {
+            return updateSymbols(function);
+        }
+
+        private static void updateSymbolsLog(final FunctionNode functionNode, final Symbol symbol, final boolean loseSlot) {
+            if (!symbol.isScope()) {
+                LOG.finest("updateSymbols: " + symbol + " => scope, because all vars in " + functionNode.getName() + " are in scope");
+            }
+            if (loseSlot && symbol.hasSlot()) {
+                LOG.finest("updateSymbols: " + symbol + " => no slot, because all vars in " + functionNode.getName() + " are in scope");
+            }
+        }
+
+        // called after a block or function node (subclass of block) is finished
+        // to correct scope and slot assignment for variables
+        private static Block updateSymbols(final Block block) {
+
+            if (!block.needsScope()) {
+                return block; // nothing to do
+            }
+
+            assert !(block instanceof FunctionNode) || block.getFunction() == block;
+
+            final FunctionNode functionNode   = block.getFunction();
+            final List<Symbol> symbols        = block.getFrame().getSymbols();
+            final boolean      allVarsInScope = functionNode.varsInScope();
+            final boolean      isVarArg       = functionNode.isVarArg();
+
+            for (final Symbol symbol : symbols) {
+                if (symbol.isInternal() || symbol.isThis()) {
+                    continue;
+                }
+
+                if (symbol.isVar()) {
+                    if (allVarsInScope || symbol.isScope()) {
+                        updateSymbolsLog(functionNode, symbol, true);
+                        symbol.setIsScope();
+                        symbol.setNeedsSlot(false);
+                    } else {
+                        assert symbol.hasSlot() : symbol + " should have a slot only, no scope";
+                    }
+                } else if (symbol.isParam() && (allVarsInScope || isVarArg || symbol.isScope())) {
+                    updateSymbolsLog(functionNode, symbol, isVarArg);
+                    symbol.setIsScope();
+                    symbol.setNeedsSlot(!isVarArg);
+                }
+            }
+
+            return block;
+        }
+    }
+
+    /**
      * Helper class to evaluate constant expressions at compile time This is
      * also a simplifier used by BinaryNode visits, UnaryNode visits and
      * conversions.
diff --git a/src/jdk/nashorn/internal/codegen/Splitter.java b/src/jdk/nashorn/internal/codegen/Splitter.java
index f7f193ee..abaab42b 100644
--- a/src/jdk/nashorn/internal/codegen/Splitter.java
+++ b/src/jdk/nashorn/internal/codegen/Splitter.java
@@ -50,6 +50,7 @@ import jdk.nashorn.internal.ir.SwitchNode;
 import jdk.nashorn.internal.ir.WhileNode;
 import jdk.nashorn.internal.ir.visitor.NodeVisitor;
 import jdk.nashorn.internal.runtime.Source;
+import jdk.nashorn.internal.runtime.options.Options;
 
 /**
  * Split the IR into smaller compile units.
@@ -68,7 +69,7 @@ public class Splitter extends NodeVisitor {
     private final Map<Node, Long> weightCache = new HashMap<>();
 
     /** Weight threshold for when to start a split. */
-    public static final long SPLIT_THRESHOLD  = 32 * 1024;
+    public static final long SPLIT_THRESHOLD = Options.getIntProperty("nashorn.compiler.splitter.threshold", 32 * 1024);
 
     /**
      * Constructor.
@@ -90,6 +91,7 @@ public class Splitter extends NodeVisitor {
         long weight = WeighNodes.weigh(functionNode);
 
         if (weight >= SPLIT_THRESHOLD) {
+            Compiler.LOG.info("Splitting '" + functionNode.getName() + "' as its weight " + weight + " exceeds split threshold " + SPLIT_THRESHOLD);
 
             functionNode.accept(this);
 
diff --git a/src/jdk/nashorn/internal/codegen/Transform.java b/src/jdk/nashorn/internal/codegen/Transform.java
deleted file mode 100644
index b3355fdb..00000000
--- a/src/jdk/nashorn/internal/codegen/Transform.java
+++ /dev/null
@@ -1,33 +0,0 @@
-/*
- * Copyright (c) 2010, 2013, Oracle and/or its affiliates. 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.  Oracle designates this
- * particular file as subject to the "Classpath" exception as provided
- * by Oracle in the LICENSE file that accompanied this code.
- *
- * 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
- * or visit www.oracle.com if you need additional information or have any
- * questions.
- */
-
-package jdk.nashorn.internal.codegen;
-
-/**
- * Code generation transform
- */
-public interface Transform {
-    //empty
-}
diff --git a/src/jdk/nashorn/internal/ir/Block.java b/src/jdk/nashorn/internal/ir/Block.java
index d8e99794..22108001 100644
--- a/src/jdk/nashorn/internal/ir/Block.java
+++ b/src/jdk/nashorn/internal/ir/Block.java
@@ -582,12 +582,10 @@ public class Block extends Node {
     }
 
     /**
-     * Reset the needs scope flag.
-     *
-     * @param needsScope  new needs scope flag
+     * Set the needs scope flag.
      */
-    public void setNeedsScope(final boolean needsScope) {
-        this.needsScope = needsScope;
+    public void setNeedsScope() {
+        this.needsScope = true;
     }
 
 }
diff --git a/src/jdk/nashorn/internal/ir/FunctionNode.java b/src/jdk/nashorn/internal/ir/FunctionNode.java
index c673bb03..15dcf0ba 100644
--- a/src/jdk/nashorn/internal/ir/FunctionNode.java
+++ b/src/jdk/nashorn/internal/ir/FunctionNode.java
@@ -43,7 +43,6 @@ import jdk.nashorn.internal.codegen.Frame;
 import jdk.nashorn.internal.codegen.MethodEmitter;
 import jdk.nashorn.internal.codegen.Namespace;
 import jdk.nashorn.internal.codegen.Splitter;
-import jdk.nashorn.internal.codegen.Transform;
 import jdk.nashorn.internal.codegen.types.Type;
 import jdk.nashorn.internal.ir.annotations.Ignore;
 import jdk.nashorn.internal.ir.visitor.NodeVisitor;
@@ -189,14 +188,9 @@ public class FunctionNode extends Block {
     /** Does this function need a scope object? */
     private static final int NEEDS_SCOPE           = HAS_ALL_VARS_IN_SCOPE | IS_VAR_ARG;
 
-
     /** What is the return type of this function? */
     private Type returnType = Type.OBJECT;
 
-    /** Transforms that have been applied to this function, a list as some transforms conceivably can run many times */
-    @Ignore
-    private final List<Class<? extends Transform>> appliedTransforms;
-
     /**
      * Used to keep track of a function's parent blocks.
      * This is needed when a (finally body) block is cloned than contains inner functions.
@@ -232,7 +226,6 @@ public class FunctionNode extends Block {
         this.labelStack        = new Stack<>();
         this.controlStack      = new Stack<>();
         this.declarations      = new ArrayList<>();
-        this.appliedTransforms = new ArrayList<>();
         // my block -> function is this. We added @SuppressWarnings("LeakingThisInConstructor") as NetBeans identifies
         // it as such a leak - this is a false positive as we're setting this into a field of the object being
         // constructed, so it can't be seen from other threads.
@@ -266,7 +259,6 @@ public class FunctionNode extends Block {
         this.labelStack        = new Stack<>();
         this.controlStack      = new Stack<>();
         this.declarations      = new ArrayList<>();
-        this.appliedTransforms = new ArrayList<>();
 
         for (final VarNode decl : functionNode.getDeclarations()) {
             declarations.add((VarNode) cs.existingOrCopy(decl)); //TODO same?
@@ -793,23 +785,6 @@ public class FunctionNode extends Block {
     }
 
     /**
-     * Check if a {@link Transform} has been taken place to this method.
-     * @param transform to check for
-     * @return true if transform has been applied
-     */
-    public boolean isTransformApplied(final Class<? extends Transform> transform) {
-        return appliedTransforms.contains(transform);
-    }
-
-    /**
-     * Tag this function with an applied transform
-     * @param transform the transform
-     */
-    public void registerTransform(final Class<? extends Transform> transform) {
-        appliedTransforms.add(transform);
-    }
-
-    /**
      * Checks if this function is a sub-function generated by splitting a larger one
      * @see Splitter
      *
diff --git a/src/jdk/nashorn/internal/ir/Symbol.java b/src/jdk/nashorn/internal/ir/Symbol.java
index 57bf2daa..d695f5ea 100644
--- a/src/jdk/nashorn/internal/ir/Symbol.java
+++ b/src/jdk/nashorn/internal/ir/Symbol.java
@@ -331,8 +331,11 @@ public final class Symbol implements Comparable<Symbol> {
      * Flag this symbol as scope as described in {@link Symbol#isScope()}
      */
     public void setIsScope() {
+        if (!isScope()) {
+            trace("SET IS SCOPE");
+        }
         flags |= IS_SCOPE;
-        getBlock().setNeedsScope(true);
+        getBlock().setNeedsScope();
     }
 
     /**
@@ -550,8 +553,10 @@ public final class Symbol implements Comparable<Symbol> {
      * @param slot valid bytecode slot, or -1 if not available
      */
     public void setSlot(final int slot) {
-        trace("SET SLOT " + slot);
-        this.slot = slot;
+        if (slot != this.slot) {
+            trace("SET SLOT " + slot);
+            this.slot = slot;
+        }
     }
 
     /**
diff --git a/src/jdk/nashorn/internal/runtime/ScriptObject.java b/src/jdk/nashorn/internal/runtime/ScriptObject.java
index 191045de..458fc74f 100644
--- a/src/jdk/nashorn/internal/runtime/ScriptObject.java
+++ b/src/jdk/nashorn/internal/runtime/ScriptObject.java
@@ -1794,14 +1794,14 @@ public abstract class ScriptObject extends PropertyListenerManager implements Pr
                typeError(Context.getGlobal(), strictErrorMessage, name, ScriptRuntime.safeToString((this)));
            }
            assert canBeFastScope || !NashornCallSiteDescriptor.isFastScope(desc);
-           final PropertyMap map = getMap();
-           return new GuardedInvocation(Lookup.EMPTY_SETTER, map.getProtoGetSwitchPoint(name), NashornGuards.getMapGuard(map));
+           final PropertyMap myMap = getMap();
+           return new GuardedInvocation(Lookup.EMPTY_SETTER, myMap.getProtoGetSwitchPoint(name), NashornGuards.getMapGuard(myMap));
     }
 
     @SuppressWarnings("unused")
     private static void setEmbed(final CallSiteDescriptor desc, final PropertyMap oldMap, final PropertyMap newMap, final MethodHandle setter, final int i, final Object self, final Object value) throws Throwable {
         final ScriptObject obj = (ScriptObject)self;
-        if(obj.trySetEmbedOrSpill(desc, oldMap, newMap, value)) {
+        if (obj.trySetEmbedOrSpill(desc, oldMap, newMap, value)) {
             obj.useEmbed(i);
             setter.invokeExact(self, value);
         }
@@ -1810,7 +1810,7 @@ public abstract class ScriptObject extends PropertyListenerManager implements Pr
     @SuppressWarnings("unused")
     private static void setSpill(final CallSiteDescriptor desc, final PropertyMap oldMap, final PropertyMap newMap, final int index, final Object self, final Object value) {
         final ScriptObject obj = (ScriptObject)self;
-        if(obj.trySetEmbedOrSpill(desc, oldMap, newMap, value)) {
+        if (obj.trySetEmbedOrSpill(desc, oldMap, newMap, value)) {
             obj.spill[index] = value;
         }
     }