Replaced old variable-inlining rule with new one. I've completely finished proper variable inlining and common subexpression elinination.

git-svn-id: https://asterixdb.googlecode.com/svn/branches/asterix_inline_vars@803 eaa15691-b419-025a-1212-ee371bd00084
diff --git a/asterix-algebra/src/main/java/edu/uci/ics/asterix/optimizer/base/RuleCollections.java b/asterix-algebra/src/main/java/edu/uci/ics/asterix/optimizer/base/RuleCollections.java
index 1c141fe..471d20b 100644
--- a/asterix-algebra/src/main/java/edu/uci/ics/asterix/optimizer/base/RuleCollections.java
+++ b/asterix-algebra/src/main/java/edu/uci/ics/asterix/optimizer/base/RuleCollections.java
@@ -18,7 +18,7 @@
 import java.util.LinkedList;
 import java.util.List;
 
-import edu.uci.ics.asterix.optimizer.rules.AsterixProperInlineVariablesRule;
+import edu.uci.ics.asterix.optimizer.rules.AsterixInlineVariablesRule;
 import edu.uci.ics.asterix.optimizer.rules.ByNameToByIndexFieldAccessRule;
 import edu.uci.ics.asterix.optimizer.rules.ConstantFoldingRule;
 import edu.uci.ics.asterix.optimizer.rules.CountVarToCountOneRule;
@@ -137,7 +137,7 @@
         condPushDownAndJoinInference.add(new InsertOuterJoinRule());
         
         condPushDownAndJoinInference.add(new RemoveRedundantVariablesRule());
-        condPushDownAndJoinInference.add(new AsterixProperInlineVariablesRule());
+        condPushDownAndJoinInference.add(new AsterixInlineVariablesRule());
         condPushDownAndJoinInference.add(new RemoveUnusedAssignAndAggregateRule());
         
         condPushDownAndJoinInference.add(new FactorRedundantGroupAndDecorVarsRule());
@@ -157,7 +157,7 @@
         // fieldLoads.add(new ByNameToByHandleFieldAccessRule()); -- disabled
         fieldLoads.add(new ByNameToByIndexFieldAccessRule());
         fieldLoads.add(new RemoveRedundantVariablesRule());
-        fieldLoads.add(new AsterixProperInlineVariablesRule());
+        fieldLoads.add(new AsterixInlineVariablesRule());
         fieldLoads.add(new RemoveUnusedAssignAndAggregateRule());
         fieldLoads.add(new ConstantFoldingRule());
         fieldLoads.add(new FeedScanCollectionToUnnest());
diff --git a/asterix-algebra/src/main/java/edu/uci/ics/asterix/optimizer/rules/AsterixInlineVariablesRule.java b/asterix-algebra/src/main/java/edu/uci/ics/asterix/optimizer/rules/AsterixInlineVariablesRule.java
index 64574cd..772a1f9 100644
--- a/asterix-algebra/src/main/java/edu/uci/ics/asterix/optimizer/rules/AsterixInlineVariablesRule.java
+++ b/asterix-algebra/src/main/java/edu/uci/ics/asterix/optimizer/rules/AsterixInlineVariablesRule.java
@@ -14,357 +14,18 @@
  */
 package edu.uci.ics.asterix.optimizer.rules;
 
-import java.util.ArrayList;
-import java.util.Iterator;
-import java.util.LinkedList;
-import java.util.List;
-
-import org.apache.commons.lang3.mutable.Mutable;
-
 import edu.uci.ics.asterix.om.functions.AsterixBuiltinFunctions;
-import edu.uci.ics.hyracks.algebricks.common.exceptions.AlgebricksException;
-import edu.uci.ics.hyracks.algebricks.common.utils.Pair;
-import edu.uci.ics.hyracks.algebricks.core.algebra.base.EquivalenceClass;
-import edu.uci.ics.hyracks.algebricks.core.algebra.base.ILogicalExpression;
-import edu.uci.ics.hyracks.algebricks.core.algebra.base.ILogicalOperator;
-import edu.uci.ics.hyracks.algebricks.core.algebra.base.ILogicalPlan;
-import edu.uci.ics.hyracks.algebricks.core.algebra.base.IOptimizationContext;
-import edu.uci.ics.hyracks.algebricks.core.algebra.base.LogicalExpressionTag;
-import edu.uci.ics.hyracks.algebricks.core.algebra.base.LogicalOperatorTag;
-import edu.uci.ics.hyracks.algebricks.core.algebra.base.LogicalVariable;
-import edu.uci.ics.hyracks.algebricks.core.algebra.expressions.AbstractFunctionCallExpression;
-import edu.uci.ics.hyracks.algebricks.core.algebra.expressions.AbstractLogicalExpression;
-import edu.uci.ics.hyracks.algebricks.core.algebra.expressions.ConstantExpression;
-import edu.uci.ics.hyracks.algebricks.core.algebra.expressions.ScalarFunctionCallExpression;
-import edu.uci.ics.hyracks.algebricks.core.algebra.expressions.VariableReferenceExpression;
-import edu.uci.ics.hyracks.algebricks.core.algebra.operators.logical.AbstractLogicalOperator;
-import edu.uci.ics.hyracks.algebricks.core.algebra.operators.logical.AbstractOperatorWithNestedPlans;
-import edu.uci.ics.hyracks.algebricks.core.algebra.operators.logical.AssignOperator;
-import edu.uci.ics.hyracks.algebricks.core.algebra.operators.logical.GroupByOperator;
-import edu.uci.ics.hyracks.algebricks.core.algebra.operators.logical.ProjectOperator;
-import edu.uci.ics.hyracks.algebricks.core.algebra.visitors.ILogicalExpressionReferenceTransform;
-import edu.uci.ics.hyracks.algebricks.core.config.AlgebricksConfig;
-import edu.uci.ics.hyracks.algebricks.core.rewriter.base.IAlgebraicRewriteRule;
+import edu.uci.ics.hyracks.algebricks.rewriter.rules.InlineVariablesRule;
 
-public class AsterixInlineVariablesRule implements IAlgebraicRewriteRule {
-
-    @Override
-    public boolean rewritePost(Mutable<ILogicalOperator> opRef, IOptimizationContext context) {
-        return false;
-    }
-
-    @Override
-    /**
-     * 
-     * Does one big DFS sweep over the plan.
-     * 
-     */
-    public boolean rewritePre(Mutable<ILogicalOperator> opRef, IOptimizationContext context) throws AlgebricksException {
-        if (context.checkIfInDontApplySet(this, opRef.getValue())) {
-            return false;
-        }
-        VariableSubstitutionVisitor substVisitor = new VariableSubstitutionVisitor(false);
-        VariableSubstitutionVisitor substVisitorForWrites = new VariableSubstitutionVisitor(true);
-        substVisitor.setContext(context);
-        substVisitorForWrites.setContext(context);
-        Pair<Boolean, Boolean> bb = collectEqClassesAndRemoveRedundantOps(opRef, context, true,
-                new LinkedList<EquivalenceClass>(), substVisitor, substVisitorForWrites);
-        return bb.first;
-    }
-
-    private Pair<Boolean, Boolean> collectEqClassesAndRemoveRedundantOps(Mutable<ILogicalOperator> opRef,
-            IOptimizationContext context, boolean first, List<EquivalenceClass> equivClasses,
-            VariableSubstitutionVisitor substVisitor, VariableSubstitutionVisitor substVisitorForWrites)
-            throws AlgebricksException {
-        AbstractLogicalOperator op = (AbstractLogicalOperator) opRef.getValue();
-        if (context.checkIfInDontApplySet(this, opRef.getValue())) {
-            new Pair<Boolean, Boolean>(false, false);
-        }
-        if (op.getOperatorTag() == LogicalOperatorTag.UNNEST_MAP) {
-            return new Pair<Boolean, Boolean>(false, false);
-        }
-        boolean modified = false;
-        boolean ecChange = false;
-        int cnt = 0;
-        for (Mutable<ILogicalOperator> i : op.getInputs()) {
-            boolean isOuterInputBranch = op.getOperatorTag() == LogicalOperatorTag.LEFTOUTERJOIN && cnt == 1;
-            List<EquivalenceClass> eqc = isOuterInputBranch ? new LinkedList<EquivalenceClass>() : equivClasses;
-
-            Pair<Boolean, Boolean> bb = (collectEqClassesAndRemoveRedundantOps(i, context, false, eqc, substVisitor,
-                    substVisitorForWrites));
-
-            if (bb.first) {
-                modified = true;
-            }
-            if (bb.second) {
-                ecChange = true;
-            }
-
-            if (isOuterInputBranch) {
-                if (AlgebricksConfig.DEBUG) {
-                    AlgebricksConfig.ALGEBRICKS_LOGGER.finest("--- Equivalence classes for inner branch of outer op.: "
-                            + eqc + "\n");
-                }
-                for (EquivalenceClass ec : eqc) {
-                    if (!ec.representativeIsConst()) {
-                        equivClasses.add(ec);
-                    }
-                }
-            }
-
-            ++cnt;
-        }
-        if (op.hasNestedPlans()) {
-            AbstractOperatorWithNestedPlans n = (AbstractOperatorWithNestedPlans) op;
-            List<EquivalenceClass> eqc = equivClasses;
-            if (n.getOperatorTag() == LogicalOperatorTag.SUBPLAN) {
-                eqc = new LinkedList<EquivalenceClass>();
-            } else {
-                eqc = equivClasses;
-            }
-            for (ILogicalPlan p : n.getNestedPlans()) {
-                for (Mutable<ILogicalOperator> r : p.getRoots()) {
-                    Pair<Boolean, Boolean> bb = collectEqClassesAndRemoveRedundantOps(r, context, false, eqc,
-                            substVisitor, substVisitorForWrites);
-                    if (bb.first) {
-                        modified = true;
-                    }
-                    if (bb.second) {
-                        ecChange = true;
-                    }
-                }
-            }
-        }
-        // we assume a variable is assigned a value only once
-        if (op.getOperatorTag() == LogicalOperatorTag.ASSIGN) {
-            AssignOperator a = (AssignOperator) op;
-            ILogicalExpression rhs = a.getExpressions().get(0).getValue();
-            if (rhs.getExpressionTag() == LogicalExpressionTag.VARIABLE) {
-                LogicalVariable varLeft = a.getVariables().get(0);
-                VariableReferenceExpression varRef = (VariableReferenceExpression) rhs;
-                LogicalVariable varRight = varRef.getVariableReference();
-
-                EquivalenceClass ecRight = findEquivClass(varRight, equivClasses);
-                if (ecRight != null) {
-                    ecRight.addMember(varLeft);
-                } else {
-                    List<LogicalVariable> m = new LinkedList<LogicalVariable>();
-                    m.add(varRight);
-                    m.add(varLeft);
-                    EquivalenceClass ec = new EquivalenceClass(m, varRight);
-                    equivClasses.add(ec);
-                    if (AlgebricksConfig.DEBUG) {
-                        AlgebricksConfig.ALGEBRICKS_LOGGER.finest("--- New equivalence class: " + ec + "\n");
-                    }
-                }
-                ecChange = true;
-            } else if (((AbstractLogicalExpression) rhs).getExpressionTag() == LogicalExpressionTag.CONSTANT) {
-                LogicalVariable varLeft = a.getVariables().get(0);
-                List<LogicalVariable> m = new LinkedList<LogicalVariable>();
-                m.add(varLeft);
-                EquivalenceClass ec = new EquivalenceClass(m, (ConstantExpression) rhs);
-                // equivClassesForParent.add(ec);
-                equivClasses.add(ec);
-                ecChange = true;
-            }
-        } else if (op.getOperatorTag() == LogicalOperatorTag.GROUP && !(context.checkIfInDontApplySet(this, op))) {
-            GroupByOperator group = (GroupByOperator) op;
-            Pair<Boolean, Boolean> r1 = processVarExprPairs(group.getGroupByList(), equivClasses);
-            Pair<Boolean, Boolean> r2 = processVarExprPairs(group.getDecorList(), equivClasses);
-            modified = modified || r1.first || r2.first;
-            ecChange = r1.second || r2.second;
-        }
-        if (op.getOperatorTag() == LogicalOperatorTag.PROJECT) {
-            assignVarsNeededByProject((ProjectOperator) op, equivClasses, context);
-        } else {
-            boolean assignRecord = false;
-            if (op.getOperatorTag() == LogicalOperatorTag.ASSIGN) {
-                AssignOperator assignOp = (AssignOperator) op;
-                List<Mutable<ILogicalExpression>> exprRefs = assignOp.getExpressions();
-                for (Mutable<ILogicalExpression> exprRef : exprRefs) {
-                    ILogicalExpression expr = exprRef.getValue();
-                    if (expr.getExpressionTag() == LogicalExpressionTag.FUNCTION_CALL) {
-                        ScalarFunctionCallExpression funExpr = (ScalarFunctionCallExpression) expr;
-                        if (funExpr.getFunctionIdentifier().equals(AsterixBuiltinFunctions.OPEN_RECORD_CONSTRUCTOR)
-                                || funExpr.getFunctionIdentifier().equals(AsterixBuiltinFunctions.CLOSED_RECORD_CONSTRUCTOR)) {
-                            assignRecord = true;
-                            break;
-                        }
-
-                    }
-                }
-            }
-
-            if (op.getOperatorTag() == LogicalOperatorTag.WRITE
-                    || op.getOperatorTag() == LogicalOperatorTag.INSERT_DELETE
-                    || op.getOperatorTag() == LogicalOperatorTag.INDEX_INSERT_DELETE
-                    || op.getOperatorTag() == LogicalOperatorTag.WRITE_RESULT || assignRecord) {
-                substVisitorForWrites.setEquivalenceClasses(equivClasses);
-                if (op.acceptExpressionTransform(substVisitorForWrites)) {
-                    modified = true;
-                }
-            } else {
-                substVisitor.setEquivalenceClasses(equivClasses);
-                if (op.acceptExpressionTransform(substVisitor)) {
-                    modified = true;
-                    if (op.getOperatorTag() == LogicalOperatorTag.GROUP) {
-                        GroupByOperator group = (GroupByOperator) op;
-                        for (Pair<LogicalVariable, Mutable<ILogicalExpression>> gp : group.getGroupByList()) {
-                            if (gp.first != null
-                                    && gp.second.getValue().getExpressionTag() == LogicalExpressionTag.VARIABLE) {
-                                LogicalVariable gv = ((VariableReferenceExpression) gp.second.getValue())
-                                        .getVariableReference();
-                                Iterator<Pair<LogicalVariable, Mutable<ILogicalExpression>>> iter = group.getDecorList()
-                                        .iterator();
-                                while (iter.hasNext()) {
-                                    Pair<LogicalVariable, Mutable<ILogicalExpression>> dp = iter.next();
-                                    if (dp.first == null
-                                            && dp.second.getValue().getExpressionTag() == LogicalExpressionTag.VARIABLE) {
-                                        LogicalVariable dv = ((VariableReferenceExpression) dp.second.getValue())
-                                                .getVariableReference();
-                                        if (dv == gv) {
-                                            // The decor variable is redundant,
-                                            // since it is
-                                            // propagated as a grouping
-                                            // variable.
-                                            EquivalenceClass ec1 = findEquivClass(gv, equivClasses);
-                                            if (ec1 != null) {
-                                                ec1.addMember(gp.first);
-                                                ec1.setVariableRepresentative(gp.first);
-                                            } else {
-                                                List<LogicalVariable> varList = new ArrayList<LogicalVariable>();
-                                                varList.add(gp.first);
-                                                varList.add(gv);
-                                                ec1 = new EquivalenceClass(varList, gp.first);
-                                            }
-                                            iter.remove();
-                                            break;
-                                        }
-                                    }
-                                }
-                            }
-                        }
-                    }
-                }
-            }
-        }
-        if (modified) {
-            context.computeAndSetTypeEnvironmentForOperator(op);
-        }
-        return new Pair<Boolean, Boolean>(modified, ecChange);
-    }
-
-    private Pair<Boolean, Boolean> processVarExprPairs(List<Pair<LogicalVariable, Mutable<ILogicalExpression>>> vePairs,
-            List<EquivalenceClass> equivClasses) {
-        boolean ecFromGroup = false;
-        boolean modified = false;
-        for (Pair<LogicalVariable, Mutable<ILogicalExpression>> p : vePairs) {
-            ILogicalExpression expr = p.second.getValue();
-            if (p.first != null && expr.getExpressionTag() == LogicalExpressionTag.VARIABLE) {
-                VariableReferenceExpression varRef = (VariableReferenceExpression) expr;
-                LogicalVariable rhsVar = varRef.getVariableReference();
-                ecFromGroup = true;
-                EquivalenceClass ecRight = findEquivClass(rhsVar, equivClasses);
-                if (ecRight != null) {
-                    LogicalVariable replacingVar = ecRight.getVariableRepresentative();
-                    if (replacingVar != null && replacingVar != rhsVar) {
-                        varRef.setVariable(replacingVar);
-                        modified = true;
-                    }
-                }
-            }
-        }
-        return new Pair<Boolean, Boolean>(modified, ecFromGroup);
-    }
-
-    // Instead of doing this, we could make Projection to be more expressive and
-    // also take constants (or even expression), at the expense of a more
-    // complex project push down.
-    private void assignVarsNeededByProject(ProjectOperator op, List<EquivalenceClass> equivClasses,
-            IOptimizationContext context) throws AlgebricksException {
-        List<LogicalVariable> prVars = op.getVariables();
-        int sz = prVars.size();
-        for (int i = 0; i < sz; i++) {
-            EquivalenceClass ec = findEquivClass(prVars.get(i), equivClasses);
-            if (ec != null) {
-                if (!ec.representativeIsConst()) {
-                    prVars.set(i, ec.getVariableRepresentative());
-                }
-            }
-        }
-    }
-
-    private final static EquivalenceClass findEquivClass(LogicalVariable var, List<EquivalenceClass> equivClasses) {
-        for (EquivalenceClass ec : equivClasses) {
-            if (ec.contains(var)) {
-                return ec;
-            }
-        }
-        return null;
-    }
-
-    private class VariableSubstitutionVisitor implements ILogicalExpressionReferenceTransform {
-        private List<EquivalenceClass> equivClasses;
-        private IOptimizationContext context;
-        private final boolean doNotSubstWithConst;
-
-        public VariableSubstitutionVisitor(boolean doNotSubstWithConst) {
-            this.doNotSubstWithConst = doNotSubstWithConst;
-        }
-
-        public void setContext(IOptimizationContext context) {
-            this.context = context;
-        }
-
-        public void setEquivalenceClasses(List<EquivalenceClass> equivClasses) {
-            this.equivClasses = equivClasses;
-        }
-
-        @Override
-        public boolean transform(Mutable<ILogicalExpression> exprRef) {
-            ILogicalExpression e = exprRef.getValue();
-            switch (((AbstractLogicalExpression) e).getExpressionTag()) {
-                case VARIABLE: {
-                    // look for a required substitution
-                    LogicalVariable var = ((VariableReferenceExpression) e).getVariableReference();
-                    if (context.shouldNotBeInlined(var)) {
-                        return false;
-                    }
-                    EquivalenceClass ec = findEquivClass(var, equivClasses);
-                    if (ec == null) {
-                        return false;
-                    }
-                    if (ec.representativeIsConst()) {
-                        if (doNotSubstWithConst) {
-                            return false;
-                        }
-                        exprRef.setValue(ec.getConstRepresentative());
-                        return true;
-                    } else {
-                        LogicalVariable r = ec.getVariableRepresentative();
-                        if (!r.equals(var)) {
-                            exprRef.setValue(new VariableReferenceExpression(r));
-                            return true;
-                        } else {
-                            return false;
-                        }
-                    }
-                }
-                case FUNCTION_CALL: {
-                    AbstractFunctionCallExpression fce = (AbstractFunctionCallExpression) e;
-                    boolean m = false;
-                    for (Mutable<ILogicalExpression> arg : fce.getArguments()) {
-                        if (transform(arg)) {
-                            m = true;
-                        }
-                    }
-                    return m;
-                }
-                default: {
-                    return false;
-                }
-            }
-        }
-
+public class AsterixInlineVariablesRule extends InlineVariablesRule {
+    
+    public AsterixInlineVariablesRule() {
+        // Do not inline field accesses because doing so would interfere with our access method rewrites.
+        // TODO: For now we must also exclude record constructor functions to avoid breaking our type casting rules
+        // IntroduceStaticTypeCastRule and IntroduceDynamicTypeCastRule. 
+        doNotInlineFuncs.add(AsterixBuiltinFunctions.FIELD_ACCESS_BY_NAME);
+        doNotInlineFuncs.add(AsterixBuiltinFunctions.FIELD_ACCESS_BY_INDEX);
+        doNotInlineFuncs.add(AsterixBuiltinFunctions.CLOSED_RECORD_CONSTRUCTOR);
+        doNotInlineFuncs.add(AsterixBuiltinFunctions.OPEN_RECORD_CONSTRUCTOR);
     }
 }
diff --git a/asterix-algebra/src/main/java/edu/uci/ics/asterix/optimizer/rules/AsterixProperInlineVariablesRule.java b/asterix-algebra/src/main/java/edu/uci/ics/asterix/optimizer/rules/AsterixProperInlineVariablesRule.java
deleted file mode 100644
index 8f74d9b..0000000
--- a/asterix-algebra/src/main/java/edu/uci/ics/asterix/optimizer/rules/AsterixProperInlineVariablesRule.java
+++ /dev/null
@@ -1,48 +0,0 @@
-/*
- * Copyright 2009-2010 by The Regents of the University of California
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * you may obtain a copy of the License from
- * 
- *     http://www.apache.org/licenses/LICENSE-2.0
- * 
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package edu.uci.ics.asterix.optimizer.rules;
-
-import edu.uci.ics.asterix.om.functions.AsterixBuiltinFunctions;
-import edu.uci.ics.hyracks.algebricks.common.exceptions.AlgebricksException;
-import edu.uci.ics.hyracks.algebricks.core.algebra.operators.logical.AbstractLogicalOperator;
-import edu.uci.ics.hyracks.algebricks.rewriter.rules.AbstractInlineVariablesRule;
-
-public class AsterixProperInlineVariablesRule extends AbstractInlineVariablesRule {
-    
-    public AsterixProperInlineVariablesRule() {
-        // Do not inline field accesses because doing so would interfere with our access method rewrites.
-        // TODO: For now we must also exclude record constructor functions to avoid breaking our type casting rules
-        // IntroduceStaticTypeCastRule and IntroduceDynamicTypeCastRule. 
-        doNotInlineFuncs.add(AsterixBuiltinFunctions.FIELD_ACCESS_BY_NAME);
-        doNotInlineFuncs.add(AsterixBuiltinFunctions.FIELD_ACCESS_BY_INDEX);
-        doNotInlineFuncs.add(AsterixBuiltinFunctions.CLOSED_RECORD_CONSTRUCTOR);
-        doNotInlineFuncs.add(AsterixBuiltinFunctions.OPEN_RECORD_CONSTRUCTOR);
-    }
-    
-    @Override
-    protected boolean performBottomUpAction(AbstractLogicalOperator op) throws AlgebricksException {
-        // Only inline variables in operators that can deal with arbitrary expressions.
-        if (!op.requiresVariableReferenceExpressions()) {
-            inlineVisitor.setOperator(op);
-            return op.acceptExpressionTransform(inlineVisitor);
-        }
-        return false;
-    }
-
-    @Override
-    protected boolean performFinalAction() throws AlgebricksException {
-        return false;
-    }    
-}