/*
* 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.core.ext.TreeLogger;
import com.google.gwt.core.ext.UnableToCompleteException;
import com.google.gwt.dev.cfg.ConfigurationProperty;
import com.google.gwt.dev.cfg.Properties;
import com.google.gwt.dev.cfg.Property;
import com.google.gwt.dev.jjs.InternalCompilerException;
import com.google.gwt.dev.jjs.ast.Context;
import com.google.gwt.dev.jjs.ast.JArrayType;
import com.google.gwt.dev.jjs.ast.JClassLiteral;
import com.google.gwt.dev.jjs.ast.JClassType;
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.JIntLiteral;
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.JNode;
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.JVisitor;
import com.google.gwt.dev.jjs.impl.ControlFlowAnalyzer.DependencyRecorder;
import com.google.gwt.dev.jjs.impl.FragmentExtractor.CfaLivenessPredicate;
import com.google.gwt.dev.jjs.impl.FragmentExtractor.LivenessPredicate;
import com.google.gwt.dev.jjs.impl.FragmentExtractor.NothingAlivePredicate;
import com.google.gwt.dev.jjs.impl.FragmentExtractor.StatementLogger;
import com.google.gwt.dev.js.ast.JsBlock;
import com.google.gwt.dev.js.ast.JsExprStmt;
import com.google.gwt.dev.js.ast.JsExpression;
import com.google.gwt.dev.js.ast.JsFunction;
import com.google.gwt.dev.js.ast.JsProgram;
import com.google.gwt.dev.js.ast.JsStatement;
import com.google.gwt.dev.js.ast.JsVars;
import com.google.gwt.dev.js.ast.JsVars.JsVar;
import com.google.gwt.dev.util.JsniRef;
import com.google.gwt.dev.util.collect.HashMap;
import com.google.gwt.dev.util.collect.HashSet;
import com.google.gwt.dev.util.collect.Lists;
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 java.util.ArrayList;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Map;
import java.util.Queue;
import java.util.Set;
import java.util.concurrent.ArrayBlockingQueue;
/**
* <p>
* Divides the code in a {@link JsProgram} into multiple fragments. The initial
* fragment is sufficient to run all of the program's functionality except for
* anything called in a callback supplied to
* {@link com.google.gwt.core.client.GWT#runAsync(com.google.gwt.core.client.RunAsyncCallback)
* GWT.runAsync()}. The remaining code should be downloadable via
* {@link com.google.gwt.core.client.impl.AsyncFragmentLoader#inject(int)}.
* </p>
*
* <p>
* The precise way the program is fragmented is an implementation detail that is
* subject to change. Whenever the fragment strategy changes,
* <code>AsyncFragmentLoader</code> must be updated in tandem. That said, the
* current fragmentation strategy is to create an initial fragment, a leftovers
* fragment, and one fragment per split point. Additionally, the splitter
* computes an initial load sequence. All runAsync calls in the initial load
* sequence are reached before any call not in the sequence. Further, any call
* in the sequence is reached before any call later in the sequence.
* </p>
*
* <p>
* The fragment for a split point contains different things depending on whether
* it is in the initial load sequence or not. If it's in the initial load
* sequence, then the fragment includes the code newly live once that split
* point is crossed, that wasn't already live for the set of split points
* earlier in the sequence. For a split point not in the initial load sequence,
* the fragment contains only code exclusive to that split point, that is, code
* that cannot be reached except via that split point. All other code goes into
* the leftovers fragment.
* </p>
*/
public class CodeSplitter {
/**
* A dependency recorder that can record multiple dependency graphs. It has
* methods for starting and finishing new dependency graphs.
*/
public interface MultipleDependencyGraphRecorder extends DependencyRecorder {
/**
* Stop recording dependencies.
*/
void close();
/**
* Stop recording the current dependency graph.
*/
void endDependencyGraph();
void open();
/**
* Start a new dependency graph. It can be an extension of a previously
* recorded dependency graph, in which case the dependencies in the previous
* graph will not be repeated.
*/
void startDependencyGraph(String name, String extnds);
}
/**
* A statement logger that immediately prints out everything live that it
* sees.
*/
private class EchoStatementLogger implements StatementLogger {
public void logStatement(JsStatement stat, boolean isIncluded) {
if (isIncluded) {
if (stat instanceof JsExprStmt) {
JsExpression expr = ((JsExprStmt) stat).getExpression();
if (expr instanceof JsFunction) {
JsFunction func = (JsFunction) expr;
if (func.getName() != null) {
JMethod method = map.nameToMethod(func.getName());
if (method != null) {
System.out.println(fullNameString(method));
}
}
}
}
if (stat instanceof JsVars) {
JsVars vars = (JsVars) stat;
for (JsVar var : vars) {
JField field = map.nameToField(var.getName());
if (field != null) {
System.out.println(fullNameString(field));
}
}
}
}
}
}
/**
* A map from program atoms to the split point, if any, that they are
* exclusive to. Atoms not exclusive to any split point are either mapped to 0
* or left out of the map entirely. Note that the map is incomplete; any entry
* not included has not been proven to be exclusive. Also, note that the
* initial load sequence is assumed to already be loaded.
*/
private static class ExclusivityMap {
public Map<JField, Integer> fields = new HashMap<JField, Integer>();
public Map<JMethod, Integer> methods = new HashMap<JMethod, Integer>();
public Map<String, Integer> strings = new HashMap<String, Integer>();
public Map<JDeclaredType, Integer> types = new HashMap<JDeclaredType, Integer>();
}
/**
* A liveness predicate that is based on an exclusivity map.
*/
private static class ExclusivityMapLivenessPredicate implements LivenessPredicate {
private final int fragment;
private final ExclusivityMap fragmentMap;
public ExclusivityMapLivenessPredicate(ExclusivityMap fragmentMap, int fragment) {
this.fragmentMap = fragmentMap;
this.fragment = fragment;
}
public boolean isLive(JDeclaredType type) {
return checkMap(fragmentMap.types, type);
}
public boolean isLive(JField field) {
return checkMap(fragmentMap.fields, field);
}
public boolean isLive(JMethod method) {
return checkMap(fragmentMap.methods, method);
}
public boolean isLive(String literal) {
return checkMap(fragmentMap.strings, literal);
}
public boolean miscellaneousStatementsAreLive() {
return true;
}
private <T> boolean checkMap(Map<T, Integer> map, T x) {
Integer entryForX = map.get(x);
if (entryForX == null) {
// unrecognized items are always live
return true;
} else {
return (fragment == entryForX) || (entryForX == 0);
}
}
}
/**
* A {@link MultipleDependencyGraphRecorder} that does nothing.
*/
public static final MultipleDependencyGraphRecorder NULL_RECORDER =
new MultipleDependencyGraphRecorder() {
public void close() {
}
public void endDependencyGraph() {
}
public void methodIsLiveBecause(JMethod liveMethod, ArrayList<JMethod> dependencyChain) {
}
public void open() {
}
public void startDependencyGraph(String name, String extnds) {
}
};
private static final String PROP_INITIAL_SEQUENCE = "compiler.splitpoint.initial.sequence";
/**
* A Java property that causes the fragment map to be logged.
*/
private static String PROP_LOG_FRAGMENT_MAP = "gwt.jjs.logFragmentMap";
public static ControlFlowAnalyzer computeInitiallyLive(JProgram jprogram) {
return computeInitiallyLive(jprogram, NULL_RECORDER);
}
public static void exec(TreeLogger logger, JProgram jprogram, JsProgram jsprogram,
JavaToJavaScriptMap map, MultipleDependencyGraphRecorder dependencyRecorder) {
if (jprogram.getRunAsyncs().size() == 0) {
// Don't do anything if there is no call to runAsync
return;
}
Event codeSplitterEvent = SpeedTracerLogger.start(CompilerEventType.CODE_SPLITTER);
dependencyRecorder.open();
new CodeSplitter(logger, jprogram, jsprogram, map, dependencyRecorder).execImpl();
dependencyRecorder.close();
codeSplitterEvent.end();
}
/**
* Find a split point as designated in the {@link #PROP_INITIAL_SEQUENCE}
* configuration property.
*/
public static int findSplitPoint(String refString, JProgram program, TreeLogger branch)
throws UnableToCompleteException {
Event codeSplitterEvent =
SpeedTracerLogger.start(CompilerEventType.CODE_SPLITTER, "phase", "findSplitPoint");
Map<String, List<Integer>> nameToSplitPoint = reverseByName(program.getRunAsyncs());
if (refString.startsWith("@")) {
JsniRef jsniRef = JsniRef.parse(refString);
if (jsniRef == null) {
branch.log(TreeLogger.ERROR, "Badly formatted JSNI reference in " + PROP_INITIAL_SEQUENCE
+ ": " + refString);
throw new UnableToCompleteException();
}
final String lookupErrorHolder[] = new String[1];
JNode referent =
JsniRefLookup.findJsniRefTarget(jsniRef, program, new JsniRefLookup.ErrorReporter() {
public void reportError(String error) {
lookupErrorHolder[0] = error;
}
});
if (referent == null) {
TreeLogger resolveLogger =
branch.branch(TreeLogger.ERROR, "Could not resolve JSNI reference: " + jsniRef);
resolveLogger.log(TreeLogger.ERROR, lookupErrorHolder[0]);
throw new UnableToCompleteException();
}
if (!(referent instanceof JMethod)) {
branch.log(TreeLogger.ERROR, "Not a method: " + referent);
throw new UnableToCompleteException();
}
JMethod method = (JMethod) referent;
String canonicalName = ReplaceRunAsyncs.getImplicitName(method);
List<Integer> splitPoints = nameToSplitPoint.get(canonicalName);
if (splitPoints == null) {
branch.log(TreeLogger.ERROR, "Method does not enclose a runAsync call: " + jsniRef);
throw new UnableToCompleteException();
}
if (splitPoints.size() > 1) {
branch.log(TreeLogger.ERROR, "Method includes multiple runAsync calls, "
+ "so it's ambiguous which one is meant: " + jsniRef);
throw new UnableToCompleteException();
}
return splitPoints.get(0);
}
// Assume it's a raw class name
List<Integer> splitPoints = nameToSplitPoint.get(refString);
if (splitPoints == null || splitPoints.size() == 0) {
branch.log(TreeLogger.ERROR, "No runAsync call is labelled with class " + refString);
throw new UnableToCompleteException();
}
if (splitPoints.size() > 1) {
branch.log(TreeLogger.ERROR, "More than one runAsync call is labelled with class "
+ refString);
throw new UnableToCompleteException();
}
int result = splitPoints.get(0);
codeSplitterEvent.end();
return result;
}
public static int getExclusiveFragmentNumber(int splitPoint) {
return splitPoint;
}
public static int getLeftoversFragmentNumber(int numSplitPoints) {
return numSplitPoints + 1;
}
/**
* Infer the number of split points for a given number of code fragments.
*/
public static int numSplitPointsForFragments(int codeFragments) {
assert (codeFragments != 2);
if (codeFragments == 1) {
return 0;
}
return codeFragments - 2;
}
/**
* Choose an initial load sequence of split points for the specified program.
* Do so by identifying split points whose code always load first, before any
* other split points. As a side effect, modifies
* {@link com.google.gwt.core.client.impl.AsyncFragmentLoader#initialLoadSequence}
* in the program being compiled.
*
* @throws UnableToCompleteException If the module specifies a bad load order
*/
public static void pickInitialLoadSequence(TreeLogger logger, JProgram program,
Properties properties) throws UnableToCompleteException {
Event codeSplitterEvent =
SpeedTracerLogger
.start(CompilerEventType.CODE_SPLITTER, "phase", "pickInitialLoadSequence");
TreeLogger branch =
logger.branch(TreeLogger.TRACE, "Looking up initial load sequence for split points");
LinkedHashSet<Integer> initialLoadSequence = new LinkedHashSet<Integer>();
ConfigurationProperty prop;
{
Property p = properties.find(PROP_INITIAL_SEQUENCE);
if (p == null) {
throw new InternalCompilerException("Could not find configuration property "
+ PROP_INITIAL_SEQUENCE);
}
if (!(p instanceof ConfigurationProperty)) {
throw new InternalCompilerException(PROP_INITIAL_SEQUENCE
+ " is not a configuration property");
}
prop = (ConfigurationProperty) p;
}
for (String refString : prop.getValues()) {
int splitPoint = findSplitPoint(refString, program, branch);
if (initialLoadSequence.contains(splitPoint)) {
branch.log(TreeLogger.ERROR, "Split point specified more than once: " + refString);
}
initialLoadSequence.add(splitPoint);
}
logInitialLoadSequence(logger, initialLoadSequence);
installInitialLoadSequenceField(program, initialLoadSequence);
program.setSplitPointInitialSequence(new ArrayList<Integer>(initialLoadSequence));
codeSplitterEvent.end();
}
/**
* <p>
* Computes the "maximum total script size" for one permutation. The total
* script size for one sequence of split points reached is the sum of the
* scripts that are downloaded for that sequence. The maximum total script
* size is the maximum such size for all possible sequences of split points.
* </p>
*
* @param jsLengths The lengths of the fragments for the compilation of one
* permutation
*/
public static int totalScriptSize(int[] jsLengths) {
/*
* The total script size is currently simple: it's the sum of all the
* individual script files.
*/
int maxTotalSize;
int numSplitPoints = numSplitPointsForFragments(jsLengths.length);
if (numSplitPoints == 0) {
maxTotalSize = jsLengths[0];
} else {
// Add up the initial and exclusive fragments
maxTotalSize = jsLengths[0];
for (int sp = 1; sp <= numSplitPoints; sp++) {
int excl = getExclusiveFragmentNumber(sp);
maxTotalSize += jsLengths[excl];
}
// Add the leftovers
maxTotalSize += jsLengths[getLeftoversFragmentNumber(numSplitPoints)];
}
return maxTotalSize;
}
private static Map<JField, JClassLiteral> buildFieldToClassLiteralMap(JProgram jprogram) {
final Map<JField, JClassLiteral> map = new HashMap<JField, JClassLiteral>();
class BuildFieldToLiteralVisitor extends JVisitor {
@Override
public void endVisit(JClassLiteral lit, Context ctx) {
map.put(lit.getField(), lit);
}
}
(new BuildFieldToLiteralVisitor()).accept(jprogram);
return map;
}
/**
* Compute the set of initially live code for this program. Such code must be
* included in the initial download of the program.
*/
private static ControlFlowAnalyzer computeInitiallyLive(JProgram jprogram,
MultipleDependencyGraphRecorder dependencyRecorder) {
dependencyRecorder.startDependencyGraph("initial", null);
ControlFlowAnalyzer cfa = new ControlFlowAnalyzer(jprogram);
cfa.setDependencyRecorder(dependencyRecorder);
cfa.traverseEntryMethods();
traverseClassArray(jprogram, cfa);
traverseImmortalTypes(jprogram, cfa);
dependencyRecorder.endDependencyGraph();
return cfa;
}
/**
* Extract the types from a set that happen to be declared types.
*/
private static Set<JDeclaredType> declaredTypesIn(Set<JReferenceType> types) {
Set<JDeclaredType> result = new HashSet<JDeclaredType>();
for (JReferenceType type : types) {
if (type instanceof JDeclaredType) {
result.add((JDeclaredType) type);
}
}
return result;
}
private static String fullNameString(JField field) {
return field.getEnclosingType().getName() + "." + field.getName();
}
private static String fullNameString(JMethod method) {
return method.getEnclosingType().getName() + "." + JProgram.getJsniSig(method);
}
private static <T> int getOrZero(Map<T, Integer> map, T key) {
Integer value = map.get(key);
return (value == null) ? 0 : value;
}
/**
* Installs the initial load sequence into AsyncFragmentLoader.BROWSER_LOADER.
* The initializer looks like this:
*
* <pre>
* AsyncFragmentLoader BROWSER_LOADER = makeBrowserLoader(1, new int[]{});
* </pre>
*
* The second argument (<code>new int[]</code>) gets replaced by an array
* corresponding to <code>initialLoadSequence</code>.
*/
private static void installInitialLoadSequenceField(JProgram program,
LinkedHashSet<Integer> initialLoadSequence) {
// Arg 1 is initialized in the source as "new int[]{}".
JMethodCall call = ReplaceRunAsyncs.getBrowserLoaderConstructor(program);
JExpression arg1 = call.getArgs().get(1);
assert arg1 instanceof JNewArray;
JArrayType arrayType = program.getTypeArray(JPrimitiveType.INT);
assert ((JNewArray) arg1).getArrayType() == arrayType;
List<JExpression> initializers = new ArrayList<JExpression>(initialLoadSequence.size());
for (int sp : initialLoadSequence) {
initializers.add(JIntLiteral.get(sp));
}
JNewArray newArray =
JNewArray.createInitializers(arg1.getSourceInfo(), arrayType, Lists
.normalizeUnmodifiable(initializers));
call.setArg(1, newArray);
}
private static <T> T last(T[] array) {
return array[array.length - 1];
}
private static void logInitialLoadSequence(TreeLogger logger,
LinkedHashSet<Integer> initialLoadSequence) {
if (!logger.isLoggable(TreeLogger.TRACE)) {
return;
}
StringBuffer message = new StringBuffer();
message.append("Initial load sequence of split points: ");
if (initialLoadSequence.isEmpty()) {
message.append("(none)");
} else {
boolean first = true;
for (int sp : initialLoadSequence) {
if (first) {
first = false;
} else {
message.append(", ");
}
message.append(sp);
}
}
logger.log(TreeLogger.TRACE, message.toString());
}
private static Map<String, List<Integer>> reverseByName(List<JRunAsync> runAsyncs) {
Map<String, List<Integer>> revmap = new HashMap<String, List<Integer>>();
for (JRunAsync replacement : runAsyncs) {
String name = replacement.getName();
if (name != null) {
List<Integer> list = revmap.get(name);
if (list == null) {
list = new ArrayList<Integer>();
revmap.put(name, list);
}
list.add(replacement.getSplitPoint());
}
}
return revmap;
}
/**
* Any instance method in the magic Array class must be in the initial
* download. The methods of that class are copied to a separate object the
* first time class Array is touched, and any methods added later won't be
* part of the copy.
*/
private static void traverseClassArray(JProgram jprogram, ControlFlowAnalyzer cfa) {
JDeclaredType typeArray = jprogram.getFromTypeMap("com.google.gwt.lang.Array");
if (typeArray == null) {
// It was pruned; nothing to do
return;
}
cfa.traverseFromInstantiationOf(typeArray);
for (JMethod method : typeArray.getMethods()) {
if (method.needsVtable()) {
cfa.traverseFrom(method);
}
}
}
/**
* Any immortal codegen types must be part of the initial download.
*/
private static void traverseImmortalTypes(JProgram jprogram,
ControlFlowAnalyzer cfa) {
for (JClassType type : jprogram.immortalCodeGenTypes) {
cfa.traverseFromInstantiationOf(type);
for (JMethod method : type.getMethods()) {
if (!method.needsVtable()) {
cfa.traverseFrom(method);
}
}
}
}
private static <T> Set<T> union(Set<? extends T> set1, Set<? extends T> set2) {
Set<T> union = new HashSet<T>();
union.addAll(set1);
union.addAll(set2);
return union;
}
private static <T> void updateMap(int entry, Map<T, Integer> map, Set<?> liveWithoutEntry,
Iterable<T> all) {
for (T each : all) {
if (!liveWithoutEntry.contains(each)) {
/*
* Note that it is fine to overwrite a preexisting entry in the map. If
* an atom is dead until split point i has been reached, and is also
* dead until entry j has been reached, then it is dead until both have
* been reached. Thus, it can be downloaded along with either i's or j's
* code.
*/
map.put(each, entry);
}
}
}
private final MultipleDependencyGraphRecorder dependencyRecorder;
private final Map<JField, JClassLiteral> fieldToLiteralOfClass;
private final FragmentExtractor fragmentExtractor;
private final LinkedHashSet<Integer> initialLoadSequence;
/**
* Code that is initially live when the program first downloads.
*/
private final ControlFlowAnalyzer initiallyLive;
private final JProgram jprogram;
private final JsProgram jsprogram;
/**
* Computed during {@link #execImpl()}, so that intermediate steps of it can
* be used as they are created.
*/
private ControlFlowAnalyzer liveAfterInitialSequence;
private final TreeLogger logger;
private final boolean logging;
private final JavaToJavaScriptMap map;
private final Set<JMethod> methodsInJavaScript;
private final int numEntries;
private CodeSplitter(TreeLogger logger, JProgram jprogram, JsProgram jsprogram,
JavaToJavaScriptMap map, MultipleDependencyGraphRecorder dependencyRecorder) {
this.logger = logger.branch(TreeLogger.TRACE, "Splitting JavaScript for incremental download");
this.jprogram = jprogram;
this.jsprogram = jsprogram;
this.map = map;
this.dependencyRecorder = dependencyRecorder;
this.initialLoadSequence = new LinkedHashSet<Integer>(jprogram.getSplitPointInitialSequence());
numEntries = jprogram.getRunAsyncs().size() + 1;
logging = Boolean.getBoolean(PROP_LOG_FRAGMENT_MAP);
fieldToLiteralOfClass = buildFieldToClassLiteralMap(jprogram);
fragmentExtractor = new FragmentExtractor(jprogram, jsprogram, map);
initiallyLive = computeInitiallyLive(jprogram, dependencyRecorder);
methodsInJavaScript = fragmentExtractor.findAllMethodsInJavaScript();
}
/**
* Create a new fragment and add it to the table of fragments.
*
* @param splitPoint The split point to associate this code with
* @param alreadyLoaded The code that should be assumed to have already been
* loaded
* @param liveNow The code that is assumed live once this fragment loads;
* anything in here but not in <code>alreadyLoaded</code> will be
* included in the created fragment
* @param stmtsToAppend Additional statements to append to the end of the new
* fragment
* @param fragmentStats The list of fragments to append to
*/
private void addFragment(int splitPoint, LivenessPredicate alreadyLoaded,
LivenessPredicate liveNow, List<JsStatement> stmtsToAppend,
Map<Integer, List<JsStatement>> fragmentStats) {
if (logging) {
System.out.println();
System.out.println("==== Fragment " + fragmentStats.size() + " ====");
fragmentExtractor.setStatementLogger(new EchoStatementLogger());
}
List<JsStatement> stats = fragmentExtractor.extractStatements(liveNow, alreadyLoaded);
stats.addAll(stmtsToAppend);
fragmentStats.put(splitPoint, stats);
}
/**
* For each split point other than those in the initial load sequence, compute
* a CFA that traces every other split point. For those that are in the
* initial load sequence, add a <code>null</code> to the list.
*/
private List<ControlFlowAnalyzer> computeAllButOneCfas() {
String dependencyGraphNameAfterInitialSequence = dependencyGraphNameAfterInitialSequence();
List<ControlFlowAnalyzer> allButOnes = new ArrayList<ControlFlowAnalyzer>();
for (JRunAsync runAsync : jprogram.getRunAsyncs()) {
int splitPoint = runAsync.getSplitPoint();
if (isInitial(splitPoint)) {
allButOnes.add(null);
continue;
}
dependencyRecorder.startDependencyGraph("sp" + splitPoint,
dependencyGraphNameAfterInitialSequence);
ControlFlowAnalyzer cfa = new ControlFlowAnalyzer(liveAfterInitialSequence);
cfa.setDependencyRecorder(dependencyRecorder);
for (JRunAsync otherRunAsync : jprogram.getRunAsyncs()) {
if (isInitial(otherRunAsync.getSplitPoint())) {
continue;
}
if (otherRunAsync == runAsync) {
continue;
}
cfa.traverseFromRunAsync(otherRunAsync);
}
dependencyRecorder.endDependencyGraph();
allButOnes.add(cfa);
}
return allButOnes;
}
/**
* Compute a CFA that covers the entire live code of the program.
*/
private ControlFlowAnalyzer computeCompleteCfa() {
dependencyRecorder.startDependencyGraph("total", null);
ControlFlowAnalyzer everything = new ControlFlowAnalyzer(jprogram);
everything.setDependencyRecorder(dependencyRecorder);
everything.traverseEverything();
dependencyRecorder.endDependencyGraph();
return everything;
}
/**
* The name of the dependency graph that corresponds to
* {@link #liveAfterInitialSequence}.
*/
private String dependencyGraphNameAfterInitialSequence() {
if (initialLoadSequence.isEmpty()) {
return "initial";
} else {
return "sp" + last(initialLoadSequence.toArray());
}
}
/**
* Map each program atom as exclusive to some split point, whenever possible.
* Also fixes up load order problems that could result from splitting code
* based on this assumption.
*/
private ExclusivityMap determineExclusivity() {
ExclusivityMap fragmentMap = new ExclusivityMap();
mapExclusiveAtoms(fragmentMap);
fixUpLoadOrderDependencies(fragmentMap);
return fragmentMap;
}
private void execImpl() {
Map<Integer, List<JsStatement>> fragmentStats = new HashMap<Integer, List<JsStatement>>();
{
/*
* Compute the base fragment. It includes everything that is live when the
* program starts.
*/
LivenessPredicate alreadyLoaded = new NothingAlivePredicate();
LivenessPredicate liveNow = new CfaLivenessPredicate(initiallyLive);
List<JsStatement> noStats = new ArrayList<JsStatement>();
addFragment(0, alreadyLoaded, liveNow, noStats, fragmentStats);
}
/*
* Compute the base fragments, for split points in the initial load
* sequence.
*/
liveAfterInitialSequence = new ControlFlowAnalyzer(initiallyLive);
String extendsCfa = "initial";
for (int sp : initialLoadSequence) {
LivenessPredicate alreadyLoaded = new CfaLivenessPredicate(liveAfterInitialSequence);
String depGraphName = "sp" + sp;
dependencyRecorder.startDependencyGraph(depGraphName, extendsCfa);
extendsCfa = depGraphName;
ControlFlowAnalyzer liveAfterSp = new ControlFlowAnalyzer(liveAfterInitialSequence);
JRunAsync runAsync = jprogram.getRunAsyncs().get(sp - 1);
assert runAsync.getSplitPoint() == sp;
liveAfterSp.traverseFromRunAsync(runAsync);
dependencyRecorder.endDependencyGraph();
LivenessPredicate liveNow = new CfaLivenessPredicate(liveAfterSp);
List<JsStatement> statsToAppend = fragmentExtractor.createOnLoadedCall(sp);
addFragment(sp, alreadyLoaded, liveNow, statsToAppend, fragmentStats);
liveAfterInitialSequence = liveAfterSp;
}
ExclusivityMap fragmentMap = determineExclusivity();
/*
* Compute the exclusively live fragments. Each includes everything
* exclusively live after entry point i.
*/
for (JRunAsync runAsync : jprogram.getRunAsyncs()) {
int i = runAsync.getSplitPoint();
if (isInitial(i)) {
continue;
}
LivenessPredicate alreadyLoaded = new ExclusivityMapLivenessPredicate(fragmentMap, 0);
LivenessPredicate liveNow = new ExclusivityMapLivenessPredicate(fragmentMap, i);
List<JsStatement> statsToAppend = fragmentExtractor.createOnLoadedCall(i);
addFragment(i, alreadyLoaded, liveNow, statsToAppend, fragmentStats);
}
/*
* Compute the leftovers fragment.
*/
{
LivenessPredicate alreadyLoaded = new CfaLivenessPredicate(liveAfterInitialSequence);
LivenessPredicate liveNow = new ExclusivityMapLivenessPredicate(fragmentMap, 0);
List<JsStatement> statsToAppend = fragmentExtractor.createOnLoadedCall(numEntries);
addFragment(numEntries, alreadyLoaded, liveNow, statsToAppend, fragmentStats);
}
// now install the new statements in the program fragments
jsprogram.setFragmentCount(fragmentStats.size());
for (int i = 0; i < fragmentStats.size(); i++) {
JsBlock fragBlock = jsprogram.getFragmentBlock(i);
fragBlock.getStatements().clear();
fragBlock.getStatements().addAll(fragmentStats.get(i));
}
}
/**
* <p>
* Patch up the fragment map to satisfy load-order dependencies, as described
* in the comment of {@link LivenessPredicate}. Load-order dependencies can be
* violated when an atom is mapped to 0 as a leftover, but it has some
* load-order dependency on an atom that was put in an exclusive fragment.
* </p>
*
* <p>
* In general, it might be possible to split things better by considering load
* order dependencies when building the fragment map. However, fixing them
* after the fact makes CodeSplitter simpler. In practice, for programs tried
* so far, there are very few load order dependency fixups that actually
* happen, so it seems better to keep the compiler simpler.
* </p>
*/
private void fixUpLoadOrderDependencies(ExclusivityMap fragmentMap) {
fixUpLoadOrderDependenciesForMethods(fragmentMap);
fixUpLoadOrderDependenciesForTypes(fragmentMap);
fixUpLoadOrderDependenciesForClassLiterals(fragmentMap);
fixUpLoadOrderDependenciesForFieldsInitializedToStrings(fragmentMap);
}
private void fixUpLoadOrderDependenciesForClassLiterals(ExclusivityMap fragmentMap) {
int numClassLitStrings = 0;
int numFixups = 0;
for (JField field : fragmentMap.fields.keySet()) {
JClassLiteral classLit = fieldToLiteralOfClass.get(field);
if (classLit != null) {
int classLitFrag = fragmentMap.fields.get(field);
for (String string : stringsIn(field.getInitializer())) {
numClassLitStrings++;
int stringFrag = getOrZero(fragmentMap.strings, string);
if (stringFrag != classLitFrag && stringFrag != 0) {
numFixups++;
fragmentMap.strings.put(string, 0);
}
}
}
}
if (logger.isLoggable(TreeLogger.DEBUG)) {
logger.log(TreeLogger.DEBUG, "Fixed up load-order dependencies by moving " + numFixups
+ " strings in class literal constructors to fragment 0, out of " + numClassLitStrings);
}
}
private void fixUpLoadOrderDependenciesForFieldsInitializedToStrings(ExclusivityMap fragmentMap) {
int numFixups = 0;
int numFieldStrings = 0;
for (JField field : fragmentMap.fields.keySet()) {
if (field.getInitializer() instanceof JStringLiteral) {
numFieldStrings++;
String string = ((JStringLiteral) field.getInitializer()).getValue();
int fieldFrag = getOrZero(fragmentMap.fields, field);
int stringFrag = getOrZero(fragmentMap.strings, string);
if (fieldFrag != stringFrag && stringFrag != 0) {
numFixups++;
fragmentMap.strings.put(string, 0);
}
}
}
if (logger.isLoggable(TreeLogger.DEBUG)) {
logger.log(TreeLogger.DEBUG, "Fixed up load-order dependencies by moving " + numFixups
+ " strings used to initialize fields to fragment 0, out of " + +numFieldStrings);
}
}
private void fixUpLoadOrderDependenciesForMethods(ExclusivityMap fragmentMap) {
int numFixups = 0;
for (JDeclaredType type : jprogram.getDeclaredTypes()) {
int typeFrag = getOrZero(fragmentMap.types, type);
if (typeFrag != 0) {
/*
* If the type is in an exclusive fragment, all its instance methods
* must be in the same one.
*/
for (JMethod method : type.getMethods()) {
if (method.needsVtable() && methodsInJavaScript.contains(method)) {
int methodFrag = getOrZero(fragmentMap.methods, method);
if (methodFrag != typeFrag) {
fragmentMap.types.put(type, 0);
numFixups++;
break;
}
}
}
}
}
if (logger.isLoggable(TreeLogger.DEBUG)) {
logger.log(TreeLogger.DEBUG,
"Fixed up load-order dependencies for instance methods by moving " + numFixups
+ " types to fragment 0, out of " + jprogram.getDeclaredTypes().size());
}
}
private void fixUpLoadOrderDependenciesForTypes(ExclusivityMap fragmentMap) {
int numFixups = 0;
Queue<JDeclaredType> typesToCheck =
new ArrayBlockingQueue<JDeclaredType>(jprogram.getDeclaredTypes().size());
typesToCheck.addAll(jprogram.getDeclaredTypes());
while (!typesToCheck.isEmpty()) {
JDeclaredType type = typesToCheck.remove();
if (type.getSuperClass() != null) {
int typeFrag = getOrZero(fragmentMap.types, type);
int supertypeFrag = getOrZero(fragmentMap.types, type.getSuperClass());
if (typeFrag != supertypeFrag && supertypeFrag != 0) {
numFixups++;
fragmentMap.types.put(type.getSuperClass(), 0);
typesToCheck.add(type.getSuperClass());
}
}
}
if (logger.isLoggable(TreeLogger.DEBUG)) {
logger.log(TreeLogger.DEBUG, "Fixed up load-order dependencies on supertypes by moving "
+ numFixups + " types to fragment 0, out of " + jprogram.getDeclaredTypes().size());
}
}
private boolean isInitial(int entry) {
return initialLoadSequence.contains(entry);
}
/**
* Map atoms to exclusive fragments. Do this by trying to find code atoms that
* are only needed by a single split point. Such code can be moved to the
* exclusively live fragment associated with that split point.
*/
private void mapExclusiveAtoms(ExclusivityMap fragmentMap) {
List<ControlFlowAnalyzer> allButOnes = computeAllButOneCfas();
ControlFlowAnalyzer everything = computeCompleteCfa();
Set<JField> allFields = new HashSet<JField>();
Set<JMethod> allMethods = new HashSet<JMethod>();
for (JNode node : everything.getLiveFieldsAndMethods()) {
if (node instanceof JField) {
allFields.add((JField) node);
}
if (node instanceof JMethod) {
allMethods.add((JMethod) node);
}
}
allFields.addAll(everything.getFieldsWritten());
for (JRunAsync runAsync : jprogram.getRunAsyncs()) {
int splitPoint = runAsync.getSplitPoint();
if (isInitial(splitPoint)) {
continue;
}
ControlFlowAnalyzer allButOne = allButOnes.get(splitPoint - 1);
Set<JNode> allLiveNodes =
union(allButOne.getLiveFieldsAndMethods(), allButOne.getFieldsWritten());
updateMap(splitPoint, fragmentMap.fields, allLiveNodes, allFields);
updateMap(splitPoint, fragmentMap.methods, allButOne.getLiveFieldsAndMethods(), allMethods);
updateMap(splitPoint, fragmentMap.strings, allButOne.getLiveStrings(), everything
.getLiveStrings());
updateMap(splitPoint, fragmentMap.types, declaredTypesIn(allButOne.getInstantiatedTypes()),
declaredTypesIn(everything.getInstantiatedTypes()));
}
}
/**
* Traverse <code>exp</code> and find all string literals within it.
*/
private Set<String> stringsIn(JExpression exp) {
final Set<String> strings = new HashSet<String>();
class StringFinder extends JVisitor {
@Override
public void endVisit(JStringLiteral stringLiteral, Context ctx) {
strings.add(stringLiteral.getValue());
}
}
(new StringFinder()).accept(exp);
return strings;
}
}