SameParameterValue optimization.
This optimization detects cases when the same value literal is used
as parameter value across the whole program.
Patch by: mike.aizatsky
Review by: spoon
git-svn-id: https://google-web-toolkit.googlecode.com/svn/trunk@6681 8db76d5a-ed1c-0410-87a9-c151d255dfc7
diff --git a/dev/core/src/com/google/gwt/dev/jjs/JavaToJavaScriptCompiler.java b/dev/core/src/com/google/gwt/dev/jjs/JavaToJavaScriptCompiler.java
index 58ee760..b3a760d 100644
--- a/dev/core/src/com/google/gwt/dev/jjs/JavaToJavaScriptCompiler.java
+++ b/dev/core/src/com/google/gwt/dev/jjs/JavaToJavaScriptCompiler.java
@@ -85,6 +85,7 @@
import com.google.gwt.dev.jjs.impl.ReplaceRebinds;
import com.google.gwt.dev.jjs.impl.ReplaceRunAsyncs;
import com.google.gwt.dev.jjs.impl.ResolveRebinds;
+import com.google.gwt.dev.jjs.impl.SameParameterValueOptimizer;
import com.google.gwt.dev.jjs.impl.SourceGenerationVisitor;
import com.google.gwt.dev.jjs.impl.TypeMap;
import com.google.gwt.dev.jjs.impl.TypeTightener;
@@ -637,7 +638,11 @@
if (isAggressivelyOptimize) {
// inlining
didChange = MethodInliner.exec(jprogram) || didChange;
+
+ // remove same parameters value
+ didChange = SameParameterValueOptimizer.exec(jprogram) || didChange;
}
+
// prove that any types that have been culled from the main tree are
// unreferenced due to type tightening?
diff --git a/dev/core/src/com/google/gwt/dev/jjs/impl/SameParameterValueOptimizer.java b/dev/core/src/com/google/gwt/dev/jjs/impl/SameParameterValueOptimizer.java
new file mode 100644
index 0000000..5df9651
--- /dev/null
+++ b/dev/core/src/com/google/gwt/dev/jjs/impl/SameParameterValueOptimizer.java
@@ -0,0 +1,186 @@
+/*
+ * 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.JMethod;
+import com.google.gwt.dev.jjs.ast.JMethodCall;
+import com.google.gwt.dev.jjs.ast.JModVisitor;
+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 java.util.IdentityHashMap;
+import java.util.List;
+import java.util.Map;
+
+/**
+ * Detects when same literal is passed as parameter value, and uses literal
+ * instead of parameter. The unused parameter will be removed by other analyses.
+ */
+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();
+ if (x.canBePolymorphic() || method.isNative()) {
+ return;
+ }
+
+ JMethod staticImpl = program.staticImplFor(method);
+ if (staticImpl != null &&
+ staticImpl.getEnclosingType().getMethods().contains(staticImpl)) {
+ // instance method is still alive.
+ return;
+ }
+
+ List<JExpression> args = x.getArgs();
+ List<JParameter> params = method.getParams();
+
+ for (int i = 0; i < args.size() && i < params.size(); i++) {
+ JParameter param = params.get(i);
+ JExpression arg = args.get(i);
+
+ if (!(arg instanceof JValueLiteral)) {
+ parameterValues.put(param, null);
+ continue;
+ }
+
+ if (!parameterValues.containsKey(param)) {
+ parameterValues.put(param, (JValueLiteral) arg);
+ continue;
+ }
+
+ JValueLiteral commonParamValue = parameterValues.get(param);
+ if (commonParamValue == null) {
+ continue;
+ }
+
+ if (!equalLiterals(commonParamValue, (JValueLiteral) arg)) {
+ parameterValues.put(param, 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);
+ }
+ }
+
+ 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 JModVisitor {
+ private CloneExpressionVisitor cloner;
+ private final JExpression expression;
+ private final JParameter parameter;
+
+ public SubstituteParameterVisitor(JParameter parameter,
+ JExpression expression) {
+ this.parameter = parameter;
+ this.expression = expression;
+ cloner = new CloneExpressionVisitor(program);
+ }
+
+ @Override
+ public void endVisit(JParameterRef x, Context ctx) {
+ if (x.getParameter() == parameter) {
+ ctx.replaceMe(cloner.cloneExpression(expression));
+ }
+ }
+ }
+
+ public static boolean exec(JProgram program) {
+ return new SameParameterValueOptimizer(program).execImpl(program);
+ }
+
+ /**
+ * 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 Map<JParameter, JValueLiteral> parameterValues =
+ new IdentityHashMap<JParameter, JValueLiteral>();
+
+ private final JProgram program;
+
+ private SameParameterValueOptimizer(JProgram program) {
+ this.program = program;
+ }
+
+ private boolean execImpl(JNode node) {
+ AnalysisVisitor analysisVisitor = new AnalysisVisitor();
+ analysisVisitor.accept(node);
+
+ boolean madeChanges = false;
+ for (JParameter parameter : parameterValues.keySet()) {
+ JValueLiteral valueLiteral = parameterValues.get(parameter);
+ if (valueLiteral != null) {
+ SubstituteParameterVisitor substituteParameterVisitor =
+ new SubstituteParameterVisitor(parameter, valueLiteral);
+ substituteParameterVisitor.accept(parameter.getEnclosingMethod());
+ madeChanges |= substituteParameterVisitor.didChange();
+ }
+ }
+
+ return madeChanges;
+ }
+}
diff --git a/dev/core/test/com/google/gwt/dev/jjs/impl/OptimizerTestBase.java b/dev/core/test/com/google/gwt/dev/jjs/impl/OptimizerTestBase.java
index 50cf016..b87d821 100644
--- a/dev/core/test/com/google/gwt/dev/jjs/impl/OptimizerTestBase.java
+++ b/dev/core/test/com/google/gwt/dev/jjs/impl/OptimizerTestBase.java
@@ -64,15 +64,18 @@
}
public static JMethod findMainMethod(JProgram program) {
+ return findMethod(program, "onModuleLoad");
+ }
+
+ public static JMethod findMethod(JProgram program, String methodName) {
JDeclaredType mainType = program.getFromTypeMap("test.EntryPoint");
- JMethod mainMethod = null;
for (JMethod method : mainType.getMethods()) {
- if (method.getName().equals("onModuleLoad")) {
- mainMethod = method;
- break;
+ if (method.getName().equals(methodName)) {
+ return method;
}
}
- return mainMethod;
+
+ return null;
}
/**
diff --git a/dev/core/test/com/google/gwt/dev/jjs/impl/SameParameterValueOptimizerTest.java b/dev/core/test/com/google/gwt/dev/jjs/impl/SameParameterValueOptimizerTest.java
new file mode 100644
index 0000000..3e69927
--- /dev/null
+++ b/dev/core/test/com/google/gwt/dev/jjs/impl/SameParameterValueOptimizerTest.java
@@ -0,0 +1,64 @@
+// Copyright 2009 Google Inc. All Rights Reserved.
+
+package com.google.gwt.dev.jjs.impl;
+
+import com.google.gwt.core.ext.UnableToCompleteException;
+import com.google.gwt.dev.jjs.ast.JMethod;
+import com.google.gwt.dev.jjs.ast.JProgram;
+
+/**
+ * Test for SameParameterValueOptimizer.
+ */
+public class SameParameterValueOptimizerTest extends OptimizerTestBase {
+ public void testSameParameter() throws Exception {
+ assertOptimize("foo", "static void foo(int i) { int j = i; }",
+ "foo(1); foo(1);").into(
+ "public static void foo(int i){",
+ " int j = 1;",
+ "}");
+ }
+
+ public void testDifferentParameter() throws Exception {
+ assertOptimize("foo", "static void foo(int i) { int j = i; }",
+ "foo(1); foo(2);").into(
+ "public static void foo(int i){",
+ " int j = i;",
+ "}");
+ }
+
+ public void testNonConstParameter() throws Exception {
+ assertOptimize("foo", "static int foo(int i) { return i; }",
+ "foo(foo(1));").into(
+ "public static int foo(int i){",
+ " return i;",
+ "}");
+ }
+
+ private OptimizationResult assertOptimize(String methodName,
+ String methodDecl, String codeSnippet) throws UnableToCompleteException {
+ addSnippetClassDecl(methodDecl);
+ JProgram program = compileSnippet("void", codeSnippet);
+ SameParameterValueOptimizer.exec(program);
+ JMethod method = findMethod(program, methodName);
+ return new OptimizationResult(method);
+ }
+
+ private static class OptimizationResult {
+ private final JMethod method;
+
+ public OptimizationResult(JMethod method) {
+ this.method = method;
+ }
+
+ public void into(String...expectedStrings) {
+ StringBuffer expected = new StringBuffer();
+ for (String s : expectedStrings) {
+ if (expected.length() != 0) {
+ expected.append("\n");
+ }
+ expected.append(s);
+ }
+ assertEquals(expected.toString(), method.toSource());
+ }
+ }
+}
