| /* |
| * 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.JAbsentArrayDimension; |
| import com.google.gwt.dev.jjs.ast.JArrayType; |
| import com.google.gwt.dev.jjs.ast.JBinaryOperation; |
| import com.google.gwt.dev.jjs.ast.JBinaryOperator; |
| import com.google.gwt.dev.jjs.ast.JCastOperation; |
| import com.google.gwt.dev.jjs.ast.JClassLiteral; |
| import com.google.gwt.dev.jjs.ast.JClassType; |
| import com.google.gwt.dev.jjs.ast.JConstructor; |
| import com.google.gwt.dev.jjs.ast.JDeclarationStatement; |
| import com.google.gwt.dev.jjs.ast.JDeclaredType; |
| import com.google.gwt.dev.jjs.ast.JExpression; |
| import com.google.gwt.dev.jjs.ast.JField; |
| import com.google.gwt.dev.jjs.ast.JFieldRef; |
| import com.google.gwt.dev.jjs.ast.JInterfaceType; |
| import com.google.gwt.dev.jjs.ast.JLocal; |
| import com.google.gwt.dev.jjs.ast.JLocalRef; |
| import com.google.gwt.dev.jjs.ast.JMethod; |
| import com.google.gwt.dev.jjs.ast.JMethodCall; |
| import com.google.gwt.dev.jjs.ast.JNewArray; |
| import com.google.gwt.dev.jjs.ast.JNewInstance; |
| 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.JPrimitiveType; |
| import com.google.gwt.dev.jjs.ast.JProgram; |
| import com.google.gwt.dev.jjs.ast.JReferenceType; |
| import com.google.gwt.dev.jjs.ast.JRunAsync; |
| import com.google.gwt.dev.jjs.ast.JStringLiteral; |
| import com.google.gwt.dev.jjs.ast.JType; |
| import com.google.gwt.dev.jjs.ast.JVariable; |
| import com.google.gwt.dev.jjs.ast.JVariableRef; |
| import com.google.gwt.dev.jjs.ast.JVisitor; |
| import com.google.gwt.dev.jjs.ast.js.JsniFieldRef; |
| import com.google.gwt.dev.jjs.ast.js.JsniMethodBody; |
| import com.google.gwt.dev.jjs.ast.js.JsniMethodRef; |
| import com.google.gwt.dev.js.ast.JsContext; |
| import com.google.gwt.dev.js.ast.JsFunction; |
| import com.google.gwt.dev.js.ast.JsName; |
| import com.google.gwt.dev.js.ast.JsNameRef; |
| import com.google.gwt.dev.js.ast.JsVisitor; |
| import com.google.gwt.dev.util.collect.Lists; |
| |
| import java.util.ArrayList; |
| import java.util.HashMap; |
| import java.util.HashSet; |
| import java.util.List; |
| import java.util.Map; |
| import java.util.Set; |
| |
| /** |
| * This class finds out what code in a program is live based on starting |
| * execution at a specified location. |
| */ |
| public class ControlFlowAnalyzer { |
| /** |
| * A callback for recording control-flow dependencies as they are discovered. |
| * See {@link ControlFlowAnalyzer#setDependencyRecorder(DependencyRecorder)}. |
| */ |
| public interface DependencyRecorder { |
| /** |
| * Used to record the dependencies of a specific method. |
| */ |
| void methodIsLiveBecause(JMethod liveMethod, ArrayList<JMethod> dependencyChain); |
| } |
| |
| /** |
| * Marks as "referenced" any types, methods, and fields that are reachable. |
| * Also marks as "instantiable" any classes and interfaces that can possibly |
| * be instantiated. |
| * |
| * TODO(later): make RescueVisitor use less stack? |
| */ |
| private class RescueVisitor extends JVisitor { |
| private final ArrayList<JMethod> curMethodStack = new ArrayList<JMethod>(); |
| |
| @Override |
| public boolean visit(JArrayType type, Context ctx) { |
| assert (referencedTypes.contains(type)); |
| boolean isInstantiated = instantiatedTypes.contains(type); |
| |
| JType leafType = type.getLeafType(); |
| int dims = type.getDims(); |
| |
| // Rescue my super array type |
| boolean didSuperType = false; |
| if (leafType instanceof JClassType) { |
| JClassType superClass = ((JClassType) leafType).getSuperClass(); |
| if (superClass != null) { |
| // FooSub[] -> Foo[] |
| rescue(program.getTypeArray(superClass, dims), true, isInstantiated); |
| didSuperType = true; |
| } |
| } else if (leafType instanceof JInterfaceType) { |
| // Intf[] -> Object[] |
| rescue(program.getTypeArray(program.getTypeJavaLangObject(), dims), true, isInstantiated); |
| didSuperType = true; |
| } |
| if (!didSuperType) { |
| if (dims > 1) { |
| // anything[][] -> Object[] |
| rescue(program.getTypeArray(program.getTypeJavaLangObject(), dims - 1), true, |
| isInstantiated); |
| } else { |
| // anything[] -> Object |
| // But instead of Object, rescue the base Array implementation type. |
| rescue(baseArrayType, true, isInstantiated); |
| } |
| } |
| |
| // Rescue super interface array types. |
| if (leafType instanceof JDeclaredType) { |
| JDeclaredType dLeafType = (JDeclaredType) leafType; |
| for (JInterfaceType intfType : dLeafType.getImplements()) { |
| JArrayType intfArray = program.getTypeArray(intfType, dims); |
| rescue(intfArray, true, isInstantiated); |
| } |
| } |
| |
| return false; |
| } |
| |
| @Override |
| public boolean visit(JBinaryOperation x, Context ctx) { |
| if (x.isAssignment() && x.getLhs() instanceof JFieldRef) { |
| fieldsWritten.add(((JFieldRef) x.getLhs()).getField()); |
| } |
| |
| // special string concat handling |
| if ((x.getOp() == JBinaryOperator.CONCAT || x.getOp() == JBinaryOperator.ASG_CONCAT)) { |
| rescueByConcat(x.getLhs().getType()); |
| rescueByConcat(x.getRhs().getType()); |
| } else if (x.getOp() == JBinaryOperator.ASG) { |
| // Don't rescue variables that are merely assigned to and never read |
| boolean doSkip = false; |
| JExpression lhs = x.getLhs(); |
| if (lhs.hasSideEffects() || isVolatileField(lhs)) { |
| /* |
| * If the lhs has side effects, skipping it would lose the side |
| * effect. If the lhs is volatile, also keep it. This behavior |
| * provides a useful idiom for test cases to prevent code from being |
| * pruned. |
| */ |
| } else if (lhs instanceof JLocalRef) { |
| // locals are ok to skip |
| doSkip = true; |
| } else if (lhs instanceof JParameterRef) { |
| // parameters are ok to skip |
| doSkip = true; |
| } else if (lhs instanceof JFieldRef) { |
| // fields must rescue the qualifier |
| doSkip = true; |
| JFieldRef fieldRef = (JFieldRef) lhs; |
| JExpression instance = fieldRef.getInstance(); |
| if (instance != null) { |
| accept(instance); |
| } |
| } |
| |
| if (doSkip) { |
| accept(x.getRhs()); |
| return false; |
| } |
| } |
| return true; |
| } |
| |
| @Override |
| public boolean visit(JCastOperation x, Context ctx) { |
| // Rescue any JavaScriptObject type that is the target of a cast. |
| JType targetType = x.getCastType(); |
| if (program.typeOracle.canBeJavaScriptObject(targetType)) { |
| rescue((JReferenceType) targetType, true, true); |
| JType exprType = x.getExpr().getType(); |
| if (program.typeOracle.isSingleJsoImpl(targetType)) { |
| /* |
| * It's a JSO interface, check if the source expr can be a live JSO 1) |
| * source is java.lang.Object (JSO could have been assigned to it) 2) |
| * source is JSO 3) source is SingleJSO interface whose implementor is |
| * live |
| */ |
| if (program.getTypeJavaLangObject() == exprType |
| || program.typeOracle.canBeJavaScriptObject(exprType)) { |
| // source is JSO or SingleJso interface whose implementor is live |
| JClassType jsoImplementor = |
| program.typeOracle.getSingleJsoImpl((JReferenceType) targetType); |
| rescue(jsoImplementor, true, true); |
| } |
| } |
| } |
| return true; |
| } |
| |
| @Override |
| public boolean visit(JClassLiteral x, Context ctx) { |
| JField field = x.getField(); |
| assert field != null; |
| rescue(field); |
| return true; |
| } |
| |
| @Override |
| public boolean visit(JClassType type, Context ctx) { |
| assert (referencedTypes.contains(type)); |
| boolean isInstantiated = instantiatedTypes.contains(type); |
| |
| // Rescue my super type |
| rescue(type.getSuperClass(), true, isInstantiated); |
| |
| // Rescue my clinit (it won't ever be explicitly referenced) |
| if (type.hasClinit()) { |
| rescue(type.getMethods().get(0)); |
| } |
| |
| // JLS 12.4.1: don't rescue my super interfaces just because I'm rescued. |
| // However, if I'm instantiated, let's mark them as instantiated. |
| for (JInterfaceType intfType : type.getImplements()) { |
| rescue(intfType, false, isInstantiated); |
| } |
| |
| rescueMembersIfInstantiable(type); |
| return false; |
| } |
| |
| @Override |
| public boolean visit(JDeclarationStatement x, Context ctx) { |
| /* |
| * A declaration by itself doesn't rescue a local (even if it has an |
| * initializer). Writes don't count, only reads. |
| */ |
| if (x.getInitializer() != null) { |
| |
| if (!isStaticFieldInitializedToLiteral(x.getVariableRef().getTarget())) { |
| /* |
| * Don't traverse literal initializers, because those become live when |
| * the variable is accessed, not when its declaration runs. |
| */ |
| accept(x.getInitializer()); |
| |
| if (x.getVariableRef().getTarget() instanceof JField) { |
| fieldsWritten.add((JField) x.getVariableRef().getTarget()); |
| } |
| } |
| } |
| |
| // If the lhs is a field ref, we have to visit its qualifier. |
| JVariableRef variableRef = x.getVariableRef(); |
| if (variableRef instanceof JFieldRef) { |
| JFieldRef fieldRef = (JFieldRef) variableRef; |
| JExpression instance = fieldRef.getInstance(); |
| if (instance != null) { |
| accept(instance); |
| } |
| } |
| return false; |
| } |
| |
| @Override |
| public boolean visit(JFieldRef ref, Context ctx) { |
| JField target = ref.getField(); |
| |
| /* |
| * JLS 12.4.1: references to static, non-final, or |
| * non-compile-time-constant fields rescue the enclosing class. JDT |
| * already folds in compile-time constants as literals, so we must rescue |
| * the enclosing types for any static fields that make it here. |
| */ |
| if (target.isStatic()) { |
| rescue(target.getEnclosingType(), true, false); |
| } |
| if (target.isStatic() || instantiatedTypes.contains(target.getEnclosingType())) { |
| rescue(target); |
| } else { |
| // It's a field whose class is not instantiable |
| if (!liveFieldsAndMethods.contains(target)) { |
| membersToRescueIfTypeIsInstantiated.add(target); |
| } |
| } |
| return true; |
| } |
| |
| @Override |
| public boolean visit(JInterfaceType type, Context ctx) { |
| boolean isReferenced = referencedTypes.contains(type); |
| boolean isInstantiated = instantiatedTypes.contains(type); |
| assert (isReferenced || isInstantiated); |
| |
| // Rescue my clinit (it won't ever be explicitly referenced) |
| if (type.hasClinit()) { |
| rescue(type.getMethods().get(0)); |
| } |
| |
| // JLS 12.4.1: don't rescue my super interfaces just because I'm rescued. |
| // However, if I'm instantiated, let's mark them as instantiated. |
| if (isInstantiated) { |
| for (JInterfaceType intfType : type.getImplements()) { |
| rescue(intfType, false, true); |
| } |
| } |
| |
| rescueMembersIfInstantiable(type); |
| return false; |
| } |
| |
| @Override |
| public boolean visit(JLocalRef ref, Context ctx) { |
| JLocal target = ref.getLocal(); |
| rescue(target); |
| return true; |
| } |
| |
| @Override |
| public boolean visit(final JMethod x, Context ctx) { |
| JReferenceType enclosingType = x.getEnclosingType(); |
| if (program.isJavaScriptObject(enclosingType)) { |
| // Calls to JavaScriptObject types rescue those types. |
| boolean instance = !x.isStatic() || program.isStaticImpl(x); |
| rescue(enclosingType, true, instance); |
| } else if (x.isStatic()) { |
| // JLS 12.4.1: references to static methods rescue the enclosing class |
| rescue(enclosingType, true, false); |
| } |
| |
| if (x.isNative()) { |
| // Manually rescue native parameter references |
| final JsniMethodBody body = (JsniMethodBody) x.getBody(); |
| final JsFunction func = body.getFunc(); |
| |
| new JsVisitor() { |
| @Override |
| public void endVisit(JsNameRef nameRef, JsContext ctx) { |
| JsName ident = nameRef.getName(); |
| |
| if (ident != null) { |
| // If we're referencing a parameter, rescue the associated |
| // JParameter |
| int index = func.getParameters().indexOf(ident.getStaticRef()); |
| if (index != -1) { |
| rescue(x.getParams().get(index)); |
| } |
| } |
| } |
| }.accept(func); |
| } |
| |
| return true; |
| } |
| |
| @Override |
| public boolean visit(JMethodCall call, Context ctx) { |
| JMethod method = call.getTarget(); |
| if (call.isVolatile() && method == runAsyncOnsuccess) { |
| /* |
| * Note: In order to preserve code splitting, don't allow code flow from the |
| * AsyncFragmentLoader implementation back into the |
| * callback.onSuccess(). If we did, the rescue path would look like |
| * JRunAsync -> AsyncFragmentLoader.runAsync() -> callback.onSuccess(). |
| * This would completely defeat code splitting as all the code on the |
| * other side of the barrier would become reachable. |
| * |
| * Code flow analysis is run separately on methods which implement |
| * RunAsyncCallback.onSuccess() as top-level entry points. |
| */ |
| return true; |
| } |
| if (method.isStatic() || program.isJavaScriptObject(method.getEnclosingType()) |
| || instantiatedTypes.contains(method.getEnclosingType())) { |
| rescue(method); |
| } else { |
| // It's a virtual method whose class is not instantiable |
| if (!liveFieldsAndMethods.contains(method)) { |
| membersToRescueIfTypeIsInstantiated.add(method); |
| } |
| } |
| |
| if (argsToRescueIfParameterRead == null || method.canBePolymorphic() |
| || call instanceof JsniMethodRef) { |
| return true; |
| } |
| |
| if (program.staticImplFor(method) != null) { |
| // CleanUpRefsVisitor does not prune these params, must rescue. |
| return true; |
| } |
| |
| return rescueArgumentsIfParametersCanBeRead(call, method); |
| } |
| |
| @Override |
| public boolean visit(JNewArray newArray, Context ctx) { |
| // rescue and instantiate the array type |
| JArrayType arrayType = newArray.getArrayType(); |
| if (newArray.dims != null) { |
| // rescue my type and all the implicitly nested types (with fewer dims) |
| int nDims = arrayType.getDims(); |
| JType leafType = arrayType.getLeafType(); |
| assert (newArray.dims.size() == nDims); |
| for (int i = 0; i < nDims; ++i) { |
| if (newArray.dims.get(i) instanceof JAbsentArrayDimension) { |
| break; |
| } |
| rescue(program.getTypeArray(leafType, nDims - i), true, true); |
| } |
| } else { |
| // just rescue my own specific type |
| rescue(arrayType, true, true); |
| } |
| return true; |
| } |
| |
| @Override |
| public boolean visit(JNewInstance x, Context ctx) { |
| // rescue and instantiate the target class! |
| rescueAndInstantiate(x.getClassType()); |
| return super.visit(x, ctx); |
| } |
| |
| @Override |
| public boolean visit(JParameterRef x, Context ctx) { |
| // rescue the parameter for future pruning purposes |
| rescue(x.getParameter()); |
| return true; |
| } |
| |
| @Override |
| public boolean visit(JsniFieldRef x, Context ctx) { |
| /* |
| * SPECIAL: this could be an assignment that passes a value from |
| * JavaScript into Java. |
| */ |
| if (x.isLvalue()) { |
| maybeRescueJavaScriptObjectPassingIntoJava(x.getField().getType()); |
| } |
| // JsniFieldRef rescues as JFieldRef |
| return visit((JFieldRef) x, ctx); |
| } |
| |
| @Override |
| public boolean visit(JsniMethodBody body, Context ctx) { |
| liveStrings.addAll(body.getUsedStrings()); |
| return true; |
| } |
| |
| @Override |
| public boolean visit(JsniMethodRef x, Context ctx) { |
| /* |
| * SPECIAL: each argument of the call passes a value from JavaScript into |
| * Java. |
| */ |
| List<JParameter> params = x.getTarget().getParams(); |
| for (int i = 0, c = params.size(); i < c; ++i) { |
| JParameter param = params.get(i); |
| maybeRescueJavaScriptObjectPassingIntoJava(param.getType()); |
| |
| /* |
| * Because we're not currently tracking methods through JSNI, we need to |
| * assume that it's not safe to prune parameters of a method referenced |
| * as such. |
| * |
| * A better solution would be to perform basic escape analysis to ensure |
| * that the function reference never escapes, or at minimum, ensure that |
| * the method is immediately called after retrieving the method |
| * reference. |
| */ |
| rescue(param); |
| } |
| // JsniMethodRef rescues as a JMethodCall |
| if (x.getTarget() instanceof JConstructor) { |
| // But if a constructor is targeted, there is an implicit 'new' op. |
| JConstructor ctor = (JConstructor) x.getTarget(); |
| rescueAndInstantiate(ctor.getEnclosingType()); |
| } |
| return visit((JMethodCall) x, ctx); |
| } |
| |
| @Override |
| public boolean visit(JStringLiteral literal, Context ctx) { |
| liveStrings.add(literal.getValue()); |
| |
| // rescue and instantiate java.lang.String |
| rescue(program.getTypeJavaLangString(), true, true); |
| return true; |
| } |
| |
| private boolean isStaticFieldInitializedToLiteral(JVariable var) { |
| if (var instanceof JField) { |
| JField field = (JField) var; |
| return field.isStatic() && field.getLiteralInitializer() != null; |
| } |
| return false; |
| } |
| |
| private boolean isVolatileField(JExpression x) { |
| if (x instanceof JFieldRef) { |
| JFieldRef xFieldRef = (JFieldRef) x; |
| if (xFieldRef.getField().isVolatile()) { |
| return true; |
| } |
| } |
| |
| return false; |
| } |
| |
| /** |
| * Subclasses of JavaScriptObject are never instantiated directly. They are |
| * implicitly created when a JSNI method passes a reference to an existing |
| * JS object into Java code. If any point in the program can pass a value |
| * from JS into Java which could potentially be cast to JavaScriptObject, we |
| * must rescue JavaScriptObject. |
| * |
| * @param type The type of the value passing from Java to JavaScript. |
| * @see com.google.gwt.core.client.JavaScriptObject |
| */ |
| private void maybeRescueJavaScriptObjectPassingIntoJava(JType type) { |
| boolean doIt = false; |
| if (program.typeOracle.canBeJavaScriptObject(type) || program.isJavaLangString(type)) { |
| doIt = true; |
| } else if (type instanceof JArrayType) { |
| /* |
| * Hackish: in our own JRE we sometimes create "not quite baked" arrays |
| * in JavaScript for expediency. |
| */ |
| JArrayType arrayType = (JArrayType) type; |
| JType elementType = arrayType.getElementType(); |
| if (elementType instanceof JPrimitiveType || program.isJavaLangString(elementType) |
| || program.typeOracle.canBeJavaScriptObject(elementType)) { |
| doIt = true; |
| } |
| } |
| if (doIt) { |
| rescue((JReferenceType) type, true, true); |
| if (program.typeOracle.isSingleJsoImpl(type)) { |
| // Cast of JSO into SingleJso interface, rescue the implementor |
| rescue(program.typeOracle.getSingleJsoImpl((JReferenceType) type), true, true); |
| } |
| } |
| } |
| |
| private boolean rescue(JMethod method) { |
| if (method != null) { |
| if (!liveFieldsAndMethods.contains(method)) { |
| liveFieldsAndMethods.add(method); |
| membersToRescueIfTypeIsInstantiated.remove(method); |
| if (dependencyRecorder != null) { |
| curMethodStack.add(method); |
| dependencyRecorder.methodIsLiveBecause(method, curMethodStack); |
| } |
| accept(method); |
| if (dependencyRecorder != null) { |
| curMethodStack.remove(curMethodStack.size() - 1); |
| } |
| if (method.isNative()) { |
| /* |
| * SPECIAL: returning from this method passes a value from |
| * JavaScript into Java. |
| */ |
| maybeRescueJavaScriptObjectPassingIntoJava(method.getType()); |
| } |
| rescueOverridingMethods(method); |
| return true; |
| } |
| } |
| return false; |
| } |
| |
| private void rescue(JReferenceType type, boolean isReferenced, boolean isInstantiated) { |
| if (type == null) { |
| return; |
| } |
| |
| /* |
| * Track references and instantiability at the granularity of run-time |
| * types. For example, ignore nullness. |
| */ |
| type = type.getUnderlyingType(); |
| |
| boolean doVisit = false; |
| if (isInstantiated && !instantiatedTypes.contains(type)) { |
| instantiatedTypes.add(type); |
| doVisit = true; |
| } |
| |
| if (isReferenced && !referencedTypes.contains(type)) { |
| referencedTypes.add(type); |
| doVisit = true; |
| } |
| |
| if (doVisit) { |
| accept(type); |
| |
| if (type instanceof JDeclaredType) { |
| for (JNode artificial : ((JDeclaredType) type).getArtificialRescues()) { |
| if (artificial instanceof JReferenceType) { |
| rescue((JReferenceType) artificial, true, true); |
| } else if (artificial instanceof JVariable) { |
| rescue((JVariable) artificial); |
| } else if (artificial instanceof JMethod) { |
| rescue((JMethod) artificial); |
| } |
| } |
| } |
| } |
| } |
| |
| private void rescue(JVariable var) { |
| if (var != null) { |
| if (liveFieldsAndMethods.add(var)) { |
| membersToRescueIfTypeIsInstantiated.remove(var); |
| if (isStaticFieldInitializedToLiteral(var)) { |
| /* |
| * Rescue literal initializers when the field is rescued, not when |
| * the static initializer runs. This allows fields initialized to |
| * string literals to only need the string literals when the field |
| * itself becomes live. |
| */ |
| accept(((JField) var).getLiteralInitializer()); |
| } else if (var instanceof JField |
| && (program.getTypeClassLiteralHolder().equals(((JField) var).getEnclosingType()))) { |
| /* |
| * Rescue just slightly less than what would normally be rescued for |
| * a field reference to the literal's field. Rescue the field |
| * itself, and its initializer, but do NOT rescue the whole |
| * enclosing class. That would pull in the clinit of that class, |
| * which has initializers for all the class literals, which in turn |
| * have all of the strings of all of the class names. |
| * |
| * This work is done in rescue() to allow JSNI references to class |
| * literals (via the @Foo::class syntax) to correctly rescue class |
| * literal initializers. |
| * |
| * TODO: Model ClassLiteral access a different way to avoid special |
| * handling. See |
| * Pruner.transformToNullFieldRef()/transformToNullMethodCall(). |
| */ |
| JField field = (JField) var; |
| accept(field.getInitializer()); |
| referencedTypes.add(field.getEnclosingType()); |
| liveFieldsAndMethods.add(field.getEnclosingType().getMethods().get(0)); |
| } else if (argsToRescueIfParameterRead != null && var instanceof JParameter) { |
| List<JExpression> list = argsToRescueIfParameterRead.remove(var); |
| if (list != null) { |
| for (JExpression arg : list) { |
| this.accept(arg); |
| } |
| } |
| } |
| } |
| } |
| } |
| |
| private void rescueAndInstantiate(JClassType type) { |
| rescue(type, true, true); |
| } |
| |
| /** |
| * The code is very tightly tied to the behavior of |
| * Pruner.CleanupRefsVisitor. CleanUpRefsVisitor will prune unread |
| * parameters, and also prune any matching arguments that don't have side |
| * effects. We want to make control flow congruent to pruning, to avoid the |
| * need to iterate over Pruner until reaching a stable point, so we avoid |
| * actually rescuing such arguments until/unless the parameter is read. |
| */ |
| private boolean rescueArgumentsIfParametersCanBeRead(JMethodCall call, JMethod method) { |
| if (call.getInstance() != null) { |
| // Explicitly visit instance since we're returning false below. |
| this.accept(call.getInstance()); |
| } |
| List<JExpression> args = call.getArgs(); |
| List<JParameter> params = method.getParams(); |
| int i = 0; |
| for (int c = params.size(); i < c; ++i) { |
| JExpression arg = args.get(i); |
| JParameter param = params.get(i); |
| if (arg.hasSideEffects() || liveFieldsAndMethods.contains(param)) { |
| this.accept(arg); |
| continue; |
| } |
| List<JExpression> list = argsToRescueIfParameterRead.get(param); |
| if (list == null) { |
| argsToRescueIfParameterRead.put(param, Lists.create(arg)); |
| } else { |
| argsToRescueIfParameterRead.put(param, Lists.add(list, arg)); |
| } |
| } |
| // Visit any "extra" arguments that exceed the param list. |
| for (int c = args.size(); i < c; ++i) { |
| this.accept(args.get(i)); |
| } |
| return false; |
| } |
| |
| /** |
| * Handle special rescues needed implicitly to support concat. |
| */ |
| private void rescueByConcat(JType type) { |
| JPrimitiveType charType = program.getTypePrimitiveChar(); |
| JClassType stringType = program.getTypeJavaLangString(); |
| if (type instanceof JReferenceType |
| && !program.typeOracle.canTriviallyCast((JReferenceType) type, stringType) |
| && type != program.getTypeNull()) { |
| /* |
| * Any reference types (except String, which works by default) that take |
| * part in a concat must rescue java.lang.Object.toString(). |
| * |
| * TODO: can we narrow the focus by walking up the type hierarchy or |
| * doing explicit toString calls? |
| */ |
| JMethod toStringMethod = program.getIndexedMethod("Object.toString"); |
| rescue(toStringMethod); |
| } else if (type == charType) { |
| /* |
| * Characters must rescue String.valueOf(char) |
| */ |
| if (stringValueOfChar == null) { |
| for (JMethod meth : stringType.getMethods()) { |
| if (meth.getName().equals("valueOf")) { |
| List<JType> params = meth.getOriginalParamTypes(); |
| if (params.size() == 1) { |
| if (params.get(0) == charType) { |
| stringValueOfChar = meth; |
| break; |
| } |
| } |
| } |
| } |
| assert (stringValueOfChar != null); |
| } |
| rescue(stringValueOfChar); |
| } |
| } |
| |
| /** |
| * If the type is instantiable, rescue any of its virtual methods that a |
| * previously seen method call could call. |
| */ |
| private void rescueMembersIfInstantiable(JDeclaredType type) { |
| if (instantiatedTypes.contains(type)) { |
| for (JMethod method : type.getMethods()) { |
| if (!method.isStatic()) { |
| if (membersToRescueIfTypeIsInstantiated.contains(method)) { |
| rescue(method); |
| continue; |
| } |
| } |
| } |
| for (JField field : type.getFields()) { |
| if (!field.isStatic()) { |
| if (membersToRescueIfTypeIsInstantiated.contains(field)) { |
| rescue(field); |
| continue; |
| } |
| } |
| } |
| } |
| } |
| |
| /** |
| * Assume that <code>method</code> is live. Rescue any overriding methods |
| * that might be called if <code>method</code> is called through virtual |
| * dispatch. |
| */ |
| private void rescueOverridingMethods(JMethod method) { |
| if (!method.isStatic()) { |
| |
| List<JMethod> overriders = methodsThatOverrideMe.get(method); |
| if (overriders != null) { |
| for (JMethod overrider : overriders) { |
| if (liveFieldsAndMethods.contains(overrider)) { |
| // The override is already alive, do nothing. |
| } else if (instantiatedTypes.contains(overrider.getEnclosingType())) { |
| // The enclosing class is alive, make my override reachable. |
| rescue(overrider); |
| } else { |
| // The enclosing class is not yet alive, put override in limbo. |
| membersToRescueIfTypeIsInstantiated.add(overrider); |
| } |
| } |
| } |
| } |
| } |
| } |
| |
| /** |
| * These are arguments that have not yet been rescued on account of the |
| * associated parameter not having been read yet. If the parameter becomes |
| * read, we will need to rescue the associated arguments. See comments in |
| * {@link #rescueArgumentsIfParametersCanBeRead}. |
| */ |
| private Map<JParameter, List<JExpression>> argsToRescueIfParameterRead; |
| |
| private final JMethod asyncFragmentOnLoad; |
| private final JDeclaredType baseArrayType; |
| private DependencyRecorder dependencyRecorder; |
| private Set<JField> fieldsWritten = new HashSet<JField>(); |
| private Set<JReferenceType> instantiatedTypes = new HashSet<JReferenceType>(); |
| private Set<JNode> liveFieldsAndMethods = new HashSet<JNode>(); |
| private Set<String> liveStrings = new HashSet<String>(); |
| |
| /** |
| * Schrodinger's members... aka "limbo". :) These are instance methods and |
| * fields that seem to be reachable, only their enclosing type is |
| * uninstantiable. We place these methods into purgatory until/unless the |
| * enclosing type is found to be instantiable. |
| */ |
| private Set<JNode> membersToRescueIfTypeIsInstantiated = new HashSet<JNode>(); |
| |
| /** |
| * A precomputed map of all instance methods onto a set of methods that |
| * override each key method. |
| */ |
| private Map<JMethod, List<JMethod>> methodsThatOverrideMe; |
| |
| private final JProgram program; |
| private Set<JReferenceType> referencedTypes = new HashSet<JReferenceType>(); |
| private final RescueVisitor rescuer = new RescueVisitor(); |
| private final JMethod runAsyncOnsuccess; |
| private JMethod stringValueOfChar = null; |
| |
| public ControlFlowAnalyzer(ControlFlowAnalyzer cfa) { |
| program = cfa.program; |
| asyncFragmentOnLoad = cfa.asyncFragmentOnLoad; |
| runAsyncOnsuccess = cfa.runAsyncOnsuccess; |
| baseArrayType = cfa.baseArrayType; |
| fieldsWritten = new HashSet<JField>(cfa.fieldsWritten); |
| instantiatedTypes = new HashSet<JReferenceType>(cfa.instantiatedTypes); |
| liveFieldsAndMethods = new HashSet<JNode>(cfa.liveFieldsAndMethods); |
| referencedTypes = new HashSet<JReferenceType>(cfa.referencedTypes); |
| stringValueOfChar = cfa.stringValueOfChar; |
| liveStrings = new HashSet<String>(cfa.liveStrings); |
| membersToRescueIfTypeIsInstantiated = |
| new HashSet<JNode>(cfa.membersToRescueIfTypeIsInstantiated); |
| if (cfa.argsToRescueIfParameterRead != null) { |
| argsToRescueIfParameterRead = |
| new HashMap<JParameter, List<JExpression>>(cfa.argsToRescueIfParameterRead); |
| } |
| methodsThatOverrideMe = cfa.methodsThatOverrideMe; |
| } |
| |
| public ControlFlowAnalyzer(JProgram program) { |
| this.program = program; |
| asyncFragmentOnLoad = program.getIndexedMethod("AsyncFragmentLoader.onLoad"); |
| runAsyncOnsuccess = program.getIndexedMethod("RunAsyncCallback.onSuccess"); |
| baseArrayType = program.getIndexedType("Array"); |
| buildMethodsOverriding(); |
| } |
| |
| /** |
| * Return the set of all fields that are written. |
| */ |
| public Set<JField> getFieldsWritten() { |
| return fieldsWritten; |
| } |
| |
| /** |
| * Return the complete set of types that have been instantiated. |
| */ |
| public Set<JReferenceType> getInstantiatedTypes() { |
| return instantiatedTypes; |
| } |
| |
| /** |
| * Return all methods that could be executed, and all variables that could be |
| * read, based on the given entry points so far. |
| */ |
| public Set<? extends JNode> getLiveFieldsAndMethods() { |
| return liveFieldsAndMethods; |
| } |
| |
| public Set<String> getLiveStrings() { |
| return liveStrings; |
| } |
| |
| /** |
| * Return the complete set of types that have been referenced. |
| */ |
| public Set<? extends JReferenceType> getReferencedTypes() { |
| return referencedTypes; |
| } |
| |
| /** |
| * Specify the {@link DependencyRecorder} to be used for future traversals. |
| * Specifying <code>null</code> means to stop recording dependencies. |
| */ |
| public void setDependencyRecorder(DependencyRecorder dr) { |
| if (dependencyRecorder != null && dr != null) { |
| throw new IllegalArgumentException("Attempting to set multiple dependency recorders"); |
| } |
| this.dependencyRecorder = dr; |
| } |
| |
| public void setForPruning() { |
| assert argsToRescueIfParameterRead == null; |
| argsToRescueIfParameterRead = new HashMap<JParameter, List<JExpression>>(); |
| } |
| |
| /** |
| * Traverse the program entry points, but don't traverse any runAsync |
| * fragments. |
| */ |
| public void traverseEntryMethods() { |
| for (JMethod method : program.getEntryMethods()) { |
| traverseFrom(method); |
| } |
| if (program.getRunAsyncs().size() > 0) { |
| /* |
| * Explicitly rescue AsyncFragmentLoader.onLoad(). It is never explicitly |
| * called anyway, until late code gen. Also, we want it in the initial |
| * fragment so all other fragments can share the code. |
| */ |
| traverseFrom(asyncFragmentOnLoad); |
| } |
| } |
| |
| public void traverseEverything() { |
| traverseEntryMethods(); |
| traverseFromRunAsyncs(); |
| /* |
| * Keep callback.onSuccess() from being pruned since we explicitly avoid |
| * visiting it. |
| */ |
| liveFieldsAndMethods.add(runAsyncOnsuccess); |
| } |
| |
| /** |
| * Assume <code>method</code> is live, and find out what else might execute. |
| */ |
| public void traverseFrom(JMethod method) { |
| rescuer.rescue(method); |
| } |
| |
| /** |
| * Assume <code>type</code> is instantiated, and find out what else will |
| * execute as a result. |
| */ |
| public void traverseFromInstantiationOf(JDeclaredType type) { |
| rescuer.rescue(type, true, true); |
| } |
| |
| public void traverseFromReferenceTo(JDeclaredType type) { |
| rescuer.rescue(type, true, false); |
| } |
| |
| /** |
| * Traverse the fragment for a specific runAsync. |
| */ |
| public void traverseFromRunAsync(JRunAsync runAsync) { |
| runAsync.traverseOnSuccess(rescuer); |
| } |
| |
| private void buildMethodsOverriding() { |
| methodsThatOverrideMe = new HashMap<JMethod, List<JMethod>>(); |
| for (JDeclaredType type : program.getDeclaredTypes()) { |
| for (JMethod method : type.getMethods()) { |
| for (JMethod overridden : program.typeOracle.getAllOverrides(method)) { |
| List<JMethod> overs = methodsThatOverrideMe.get(overridden); |
| if (overs == null) { |
| overs = new ArrayList<JMethod>(); |
| methodsThatOverrideMe.put(overridden, overs); |
| } |
| overs.add(method); |
| } |
| } |
| } |
| } |
| |
| /** |
| * Traverse the fragments for all runAsyncs. |
| */ |
| private void traverseFromRunAsyncs() { |
| for (JRunAsync runAsync : program.getRunAsyncs()) { |
| traverseFromRunAsync(runAsync); |
| } |
| } |
| } |
