| /* |
| * Copyright 2008 Google Inc. |
| * |
| * 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 at |
| * |
| * 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 com.google.gwt.dev.jjs.impl; |
| |
| import com.google.gwt.dev.jjs.ast.Context; |
| import com.google.gwt.dev.jjs.ast.JBinaryOperation; |
| import com.google.gwt.dev.jjs.ast.JExpression; |
| import com.google.gwt.dev.jjs.ast.JLiteral; |
| import com.google.gwt.dev.jjs.ast.JMethod; |
| import com.google.gwt.dev.jjs.ast.JMethodCall; |
| import com.google.gwt.dev.jjs.ast.JNode; |
| import com.google.gwt.dev.jjs.ast.JParameter; |
| import com.google.gwt.dev.jjs.ast.JParameterRef; |
| import com.google.gwt.dev.jjs.ast.JPostfixOperation; |
| import com.google.gwt.dev.jjs.ast.JPrefixOperation; |
| import com.google.gwt.dev.jjs.ast.JProgram; |
| import com.google.gwt.dev.jjs.ast.JValueLiteral; |
| import com.google.gwt.dev.jjs.ast.JVisitor; |
| import com.google.gwt.dev.jjs.ast.js.JsniMethodBody; |
| import com.google.gwt.dev.jjs.ast.js.JsniMethodRef; |
| import com.google.gwt.dev.util.log.speedtracer.CompilerEventType; |
| import com.google.gwt.dev.util.log.speedtracer.SpeedTracerLogger; |
| import com.google.gwt.dev.util.log.speedtracer.SpeedTracerLogger.Event; |
| import com.google.gwt.thirdparty.guava.common.annotations.VisibleForTesting; |
| import com.google.gwt.thirdparty.guava.common.collect.Maps; |
| import com.google.gwt.thirdparty.guava.common.collect.Sets; |
| |
| import java.util.List; |
| import java.util.Map; |
| import java.util.Set; |
| |
| /** |
| * Detects when same literal is passed as parameter value, and uses literal |
| * instead of parameter. The unused parameter will be removed by other analyses. |
| */ |
| // TODO: this optimization can mistakenly act on methods such as LongLib.fromInt |
| // since only one call is seen in LongLib itself. |
| public class SameParameterValueOptimizer { |
| /** |
| * Fill parameterValues map. |
| */ |
| private class AnalysisVisitor extends JVisitor { |
| @Override |
| public void endVisit(JBinaryOperation x, Context ctx) { |
| if (x.isAssignment() && x.getLhs() instanceof JParameterRef) { |
| parameterValues.put(((JParameterRef) x.getLhs()).getParameter(), null); |
| } |
| } |
| |
| @Override |
| public void endVisit(JMethodCall x, Context ctx) { |
| JMethod method = x.getTarget(); |
| |
| // A quick check to reduce extra work needed otherwise... |
| if (isNotOptimizable(method)) { |
| return; |
| } |
| |
| List<JExpression> arguments = x.getArgs(); |
| List<JParameter> parameters = method.getParams(); |
| |
| for (int i = 0; i < arguments.size() && i < parameters.size(); i++) { |
| JParameter parameter = parameters.get(i); |
| JExpression argument = arguments.get(i); |
| |
| if (!(argument instanceof JValueLiteral)) { |
| parameterValues.put(parameter, null); |
| continue; |
| } |
| |
| if (!parameterValues.containsKey(parameter)) { |
| parameterValues.put(parameter, (JValueLiteral) argument); |
| continue; |
| } |
| |
| JValueLiteral commonParamValue = parameterValues.get(parameter); |
| if (commonParamValue == null) { |
| continue; |
| } |
| |
| if (!equalLiterals(commonParamValue, (JValueLiteral) argument)) { |
| parameterValues.put(parameter, null); |
| } |
| } |
| } |
| |
| @Override |
| public void endVisit(JPostfixOperation x, Context ctx) { |
| if (x.getArg() instanceof JParameterRef) { |
| parameterValues.put(((JParameterRef) x.getArg()).getParameter(), null); |
| } |
| } |
| |
| @Override |
| public void endVisit(JPrefixOperation x, Context ctx) { |
| if (x.getArg() instanceof JParameterRef) { |
| parameterValues.put(((JParameterRef) x.getArg()).getParameter(), null); |
| } |
| } |
| |
| @Override |
| public void endVisit(JsniMethodBody x, Context ctx) { |
| for (JsniMethodRef methodRef : x.getJsniMethodRefs()) { |
| nonOptimizableMethods.add(methodRef.getTarget()); |
| } |
| } |
| |
| @Override |
| public boolean visit(JMethod x, Context ctx) { |
| if (isNotOptimizable(x)) { |
| nonOptimizableMethods.add(x); |
| } |
| return true; |
| } |
| |
| private boolean isNotOptimizable(JMethod x) { |
| return x.needsDynamicDispatch() || x.canBeReferencedExternally(); |
| } |
| |
| private boolean equalLiterals(JValueLiteral l1, JValueLiteral l2) { |
| Object v1 = l1.getValueObj(); |
| Object v2 = l2.getValueObj(); |
| |
| if (v1 == v2) { |
| return true; |
| } |
| |
| if (v1 == null || v2 == null) { |
| return false; |
| } |
| |
| return v1.equals(v2); |
| } |
| } |
| |
| /** |
| * Substitute all parameter references with expression. |
| */ |
| private class SubstituteParameterVisitor extends JChangeTrackingVisitor { |
| private final CloneExpressionVisitor cloner; |
| |
| public SubstituteParameterVisitor(OptimizerContext optimizerCtx) { |
| super(optimizerCtx); |
| cloner = new CloneExpressionVisitor(); |
| } |
| |
| @Override |
| public boolean enter(JMethod x, Context ctx) { |
| if (nonOptimizableMethods.contains(x)) { |
| return false; |
| } |
| for (JParameter parameter : x.getParams()) { |
| if (parameterValues.get(parameter) != null) { |
| return true; |
| } |
| } |
| return false; |
| } |
| |
| @Override |
| public void endVisit(JParameterRef x, Context ctx) { |
| JParameter parameter = x.getParameter(); |
| JLiteral value = parameterValues.get(parameter); |
| if (value != null) { |
| ctx.replaceMe(cloner.cloneExpression(Simplifier.cast(parameter.getType(), value))); |
| } |
| } |
| } |
| |
| private static final String NAME = SameParameterValueOptimizer.class.getSimpleName(); |
| |
| @VisibleForTesting |
| static OptimizerStats exec(JProgram program) { |
| return exec(program, OptimizerContext.NULL_OPTIMIZATION_CONTEXT); |
| } |
| |
| public static OptimizerStats exec(JProgram program, OptimizerContext optimizerCtx) { |
| Event optimizeEvent = SpeedTracerLogger.start(CompilerEventType.OPTIMIZE, "optimizer", NAME); |
| OptimizerStats stats = new SameParameterValueOptimizer(program).execImpl(program, optimizerCtx); |
| optimizerCtx.incOptimizationStep(); |
| optimizeEvent.end("didChange", "" + stats.didChange()); |
| return stats; |
| } |
| |
| /** |
| * Parameter values. |
| * |
| * If doesn't contain a parameter, then its value is unknown. If contains |
| * parameter, and value is null - the parameter's value is not the same across |
| * all calls. If value is not null - the parameter's value is the same across |
| * all calls. |
| */ |
| private final Map<JParameter, JValueLiteral> parameterValues = Maps.newIdentityHashMap(); |
| private final JProgram program; |
| |
| /** |
| * These methods should not be tried to be optimized, either because they are polymorphic or we |
| * cannot see all the calls. |
| */ |
| private final Set<JMethod> nonOptimizableMethods = Sets.newHashSet(); |
| |
| private SameParameterValueOptimizer(JProgram program) { |
| this.program = program; |
| } |
| |
| private OptimizerStats execImpl(JNode node, OptimizerContext optimizerCtx) { |
| OptimizerStats stats = new OptimizerStats(NAME); |
| new AnalysisVisitor().accept(node); |
| SubstituteParameterVisitor substituteParameterVisitor = |
| new SubstituteParameterVisitor(optimizerCtx); |
| substituteParameterVisitor.accept(node); |
| stats.recordModified(substituteParameterVisitor.getNumMods()); |
| |
| JavaAstVerifier.assertProgramIsConsistent(program); |
| return stats; |
| } |
| } |