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Rhino is an open-source implementation of JavaScript written entirely in Java. It is typically
embedded into Java applications to provide scripting to end users.
/* -*- Mode: java; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
*
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
package org.mozilla.javascript.optimizer;
import static org.mozilla.classfile.ClassFileWriter.ACC_FINAL;
import static org.mozilla.classfile.ClassFileWriter.ACC_PRIVATE;
import static org.mozilla.classfile.ClassFileWriter.ACC_PROTECTED;
import static org.mozilla.classfile.ClassFileWriter.ACC_PUBLIC;
import static org.mozilla.classfile.ClassFileWriter.ACC_STATIC;
import static org.mozilla.classfile.ClassFileWriter.ACC_VOLATILE;
import java.lang.reflect.Constructor;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import org.mozilla.classfile.ByteCode;
import org.mozilla.classfile.ClassFileWriter;
import org.mozilla.javascript.CompilerEnvirons;
import org.mozilla.javascript.Context;
import org.mozilla.javascript.Evaluator;
import org.mozilla.javascript.Function;
import org.mozilla.javascript.GeneratedClassLoader;
import org.mozilla.javascript.Kit;
import org.mozilla.javascript.NativeFunction;
import org.mozilla.javascript.ObjArray;
import org.mozilla.javascript.ObjToIntMap;
import org.mozilla.javascript.RhinoException;
import org.mozilla.javascript.Script;
import org.mozilla.javascript.Scriptable;
import org.mozilla.javascript.SecurityController;
import org.mozilla.javascript.Token;
import org.mozilla.javascript.ast.FunctionNode;
import org.mozilla.javascript.ast.Name;
import org.mozilla.javascript.ast.ScriptNode;
/**
* This class generates code for a given IR tree.
*
* @author Norris Boyd
* @author Roger Lawrence
*/
public class Codegen implements Evaluator
{
@Override
public void captureStackInfo(RhinoException ex) {
throw new UnsupportedOperationException();
}
@Override
public String getSourcePositionFromStack(Context cx, int[] linep) {
throw new UnsupportedOperationException();
}
@Override
public String getPatchedStack(RhinoException ex, String nativeStackTrace) {
throw new UnsupportedOperationException();
}
@Override
public List getScriptStack(RhinoException ex) {
throw new UnsupportedOperationException();
}
@Override
public void setEvalScriptFlag(Script script) {
throw new UnsupportedOperationException();
}
@Override
public Object compile(CompilerEnvirons compilerEnv,
ScriptNode tree,
String encodedSource,
boolean returnFunction)
{
int serial;
synchronized (globalLock) {
serial = ++globalSerialClassCounter;
}
String baseName = "c";
if (tree.getSourceName().length() > 0) {
baseName = tree.getSourceName().replaceAll("\\W", "_");
if (!Character.isJavaIdentifierStart(baseName.charAt(0))) {
baseName = "_" + baseName;
}
}
String mainClassName = "org.mozilla.javascript.gen." + baseName + "_" + serial;
byte[] mainClassBytes = compileToClassFile(compilerEnv, mainClassName,
tree, encodedSource,
returnFunction);
return new Object[] { mainClassName, mainClassBytes };
}
@Override
public Script createScriptObject(Object bytecode,
Object staticSecurityDomain)
{
Class cl = defineClass(bytecode, staticSecurityDomain);
Script script;
try {
script = (Script)cl.newInstance();
} catch (Exception ex) {
throw new RuntimeException
("Unable to instantiate compiled class:" + ex.toString());
}
return script;
}
@Override
public Function createFunctionObject(Context cx, Scriptable scope,
Object bytecode,
Object staticSecurityDomain)
{
Class cl = defineClass(bytecode, staticSecurityDomain);
NativeFunction f;
try {
Constructorctor = cl.getConstructors()[0];
Object[] initArgs = { scope, cx, Integer.valueOf(0) };
f = (NativeFunction)ctor.newInstance(initArgs);
} catch (Exception ex) {
throw new RuntimeException
("Unable to instantiate compiled class:"+ex.toString());
}
return f;
}
private Class defineClass(Object bytecode,
Object staticSecurityDomain)
{
Object[] nameBytesPair = (Object[])bytecode;
String className = (String)nameBytesPair[0];
byte[] classBytes = (byte[])nameBytesPair[1];
// The generated classes in this case refer only to Rhino classes
// which must be accessible through this class loader
ClassLoader rhinoLoader = getClass().getClassLoader();
GeneratedClassLoader loader;
loader = SecurityController.createLoader(rhinoLoader,
staticSecurityDomain);
Exception e;
try {
Class cl = loader.defineClass(className, classBytes);
loader.linkClass(cl);
return cl;
} catch (SecurityException x) {
e = x;
} catch (IllegalArgumentException x) {
e = x;
}
throw new RuntimeException("Malformed optimizer package " + e);
}
public byte[] compileToClassFile(CompilerEnvirons compilerEnv,
String mainClassName,
ScriptNode scriptOrFn,
String encodedSource,
boolean returnFunction)
{
this.compilerEnv = compilerEnv;
transform(scriptOrFn);
if (Token.printTrees) {
System.out.println(scriptOrFn.toStringTree(scriptOrFn));
}
if (returnFunction) {
scriptOrFn = scriptOrFn.getFunctionNode(0);
}
initScriptNodesData(scriptOrFn);
this.mainClassName = mainClassName;
this.mainClassSignature = ClassFileWriter.classNameToSignature(mainClassName);
return generateCode(encodedSource);
}
private void transform(ScriptNode tree)
{
initOptFunctions_r(tree);
int optLevel = compilerEnv.getOptimizationLevel();
Map possibleDirectCalls = null;
if (optLevel > 0) {
/*
* Collect all of the contained functions into a hashtable
* so that the call optimizer can access the class name & parameter
* count for any call it encounters
*/
if (tree.getType() == Token.SCRIPT) {
int functionCount = tree.getFunctionCount();
for (int i = 0; i != functionCount; ++i) {
OptFunctionNode ofn = OptFunctionNode.get(tree, i);
if (ofn.fnode.getFunctionType()
== FunctionNode.FUNCTION_STATEMENT)
{
String name = ofn.fnode.getName();
if (name.length() != 0) {
if (possibleDirectCalls == null) {
possibleDirectCalls = new HashMap();
}
possibleDirectCalls.put(name, ofn);
}
}
}
}
}
if (possibleDirectCalls != null) {
directCallTargets = new ObjArray();
}
OptTransformer ot = new OptTransformer(possibleDirectCalls,
directCallTargets);
ot.transform(tree, compilerEnv);
if (optLevel > 0) {
(new Optimizer()).optimize(tree);
}
}
private static void initOptFunctions_r(ScriptNode scriptOrFn)
{
for (int i = 0, N = scriptOrFn.getFunctionCount(); i != N; ++i) {
FunctionNode fn = scriptOrFn.getFunctionNode(i);
new OptFunctionNode(fn);
initOptFunctions_r(fn);
}
}
private void initScriptNodesData(ScriptNode scriptOrFn)
{
ObjArray x = new ObjArray();
collectScriptNodes_r(scriptOrFn, x);
int count = x.size();
scriptOrFnNodes = new ScriptNode[count];
x.toArray(scriptOrFnNodes);
scriptOrFnIndexes = new ObjToIntMap(count);
for (int i = 0; i != count; ++i) {
scriptOrFnIndexes.put(scriptOrFnNodes[i], i);
}
}
private static void collectScriptNodes_r(ScriptNode n,
ObjArray x)
{
x.add(n);
int nestedCount = n.getFunctionCount();
for (int i = 0; i != nestedCount; ++i) {
collectScriptNodes_r(n.getFunctionNode(i), x);
}
}
private byte[] generateCode(String encodedSource)
{
boolean hasScript = (scriptOrFnNodes[0].getType() == Token.SCRIPT);
boolean hasFunctions = (scriptOrFnNodes.length > 1 || !hasScript);
boolean isStrictMode = scriptOrFnNodes[0].isInStrictMode();
String sourceFile = null;
if (compilerEnv.isGenerateDebugInfo()) {
sourceFile = scriptOrFnNodes[0].getSourceName();
}
ClassFileWriter cfw = new ClassFileWriter(mainClassName,
SUPER_CLASS_NAME,
sourceFile);
cfw.addField(ID_FIELD_NAME, "I", ACC_PRIVATE);
if (hasFunctions) {
generateFunctionConstructor(cfw);
}
if (hasScript) {
cfw.addInterface("org/mozilla/javascript/Script");
generateScriptCtor(cfw);
generateMain(cfw);
generateExecute(cfw);
}
generateCallMethod(cfw, isStrictMode);
generateResumeGenerator(cfw);
generateNativeFunctionOverrides(cfw, encodedSource);
int count = scriptOrFnNodes.length;
for (int i = 0; i != count; ++i) {
ScriptNode n = scriptOrFnNodes[i];
BodyCodegen bodygen = new BodyCodegen();
bodygen.cfw = cfw;
bodygen.codegen = this;
bodygen.compilerEnv = compilerEnv;
bodygen.scriptOrFn = n;
bodygen.scriptOrFnIndex = i;
bodygen.generateBodyCode();
if (n.getType() == Token.FUNCTION) {
OptFunctionNode ofn = OptFunctionNode.get(n);
generateFunctionInit(cfw, ofn);
if (ofn.isTargetOfDirectCall()) {
emitDirectConstructor(cfw, ofn);
}
}
}
emitRegExpInit(cfw);
emitConstantDudeInitializers(cfw);
return cfw.toByteArray();
}
private void emitDirectConstructor(ClassFileWriter cfw,
OptFunctionNode ofn)
{
/*
we generate ..
Scriptable directConstruct() {
Scriptable newInstance = createObject(cx, scope);
Object val = (cx, scope, newInstance, );
if (val instanceof Scriptable) {
return (Scriptable) val;
}
return newInstance;
}
*/
cfw.startMethod(getDirectCtorName(ofn.fnode),
getBodyMethodSignature(ofn.fnode),
(short)(ACC_STATIC | ACC_PRIVATE));
int argCount = ofn.fnode.getParamCount();
int firstLocal = (4 + argCount * 3) + 1;
cfw.addALoad(0); // this
cfw.addALoad(1); // cx
cfw.addALoad(2); // scope
cfw.addInvoke(ByteCode.INVOKEVIRTUAL,
"org/mozilla/javascript/BaseFunction",
"createObject",
"(Lorg/mozilla/javascript/Context;"
+"Lorg/mozilla/javascript/Scriptable;"
+")Lorg/mozilla/javascript/Scriptable;");
cfw.addAStore(firstLocal);
cfw.addALoad(0);
cfw.addALoad(1);
cfw.addALoad(2);
cfw.addALoad(firstLocal);
for (int i = 0; i < argCount; i++) {
cfw.addALoad(4 + (i * 3));
cfw.addDLoad(5 + (i * 3));
}
cfw.addALoad(4 + argCount * 3);
cfw.addInvoke(ByteCode.INVOKESTATIC,
mainClassName,
getBodyMethodName(ofn.fnode),
getBodyMethodSignature(ofn.fnode));
int exitLabel = cfw.acquireLabel();
cfw.add(ByteCode.DUP); // make a copy of direct call result
cfw.add(ByteCode.INSTANCEOF, "org/mozilla/javascript/Scriptable");
cfw.add(ByteCode.IFEQ, exitLabel);
// cast direct call result
cfw.add(ByteCode.CHECKCAST, "org/mozilla/javascript/Scriptable");
cfw.add(ByteCode.ARETURN);
cfw.markLabel(exitLabel);
cfw.addALoad(firstLocal);
cfw.add(ByteCode.ARETURN);
cfw.stopMethod((short)(firstLocal + 1));
}
static boolean isGenerator(ScriptNode node)
{
return (node.getType() == Token.FUNCTION ) &&
((FunctionNode)node).isGenerator();
}
// How dispatch to generators works:
// Two methods are generated corresponding to a user-written generator.
// One of these creates a generator object (NativeGenerator), which is
// returned to the user. The other method contains all of the body code
// of the generator.
// When a user calls a generator, the call() method dispatches control to
// to the method that creates the NativeGenerator object. Subsequently when
// the user invokes .next(), .send() or any such method on the generator
// object, the resumeGenerator() below dispatches the call to the
// method corresponding to the generator body. As a matter of convention
// the generator body is given the name of the generator activation function
// appended by "_gen".
private void generateResumeGenerator(ClassFileWriter cfw)
{
boolean hasGenerators = false;
for (int i=0; i < scriptOrFnNodes.length; i++) {
if (isGenerator(scriptOrFnNodes[i]))
hasGenerators = true;
}
// if there are no generators defined, we don't implement a
// resumeGenerator(). The base class provides a default implementation.
if (!hasGenerators)
return;
cfw.startMethod("resumeGenerator",
"(Lorg/mozilla/javascript/Context;" +
"Lorg/mozilla/javascript/Scriptable;" +
"ILjava/lang/Object;" +
"Ljava/lang/Object;)Ljava/lang/Object;",
(short)(ACC_PUBLIC | ACC_FINAL));
// load arguments for dispatch to the corresponding *_gen method
cfw.addALoad(0);
cfw.addALoad(1);
cfw.addALoad(2);
cfw.addALoad(4);
cfw.addALoad(5);
cfw.addILoad(3);
cfw.addLoadThis();
cfw.add(ByteCode.GETFIELD, cfw.getClassName(), ID_FIELD_NAME, "I");
int startSwitch = cfw.addTableSwitch(0, scriptOrFnNodes.length - 1);
cfw.markTableSwitchDefault(startSwitch);
int endlabel = cfw.acquireLabel();
for (int i = 0; i < scriptOrFnNodes.length; i++) {
ScriptNode n = scriptOrFnNodes[i];
cfw.markTableSwitchCase(startSwitch, i, (short)6);
if (isGenerator(n)) {
String type = "(" +
mainClassSignature +
"Lorg/mozilla/javascript/Context;" +
"Lorg/mozilla/javascript/Scriptable;" +
"Ljava/lang/Object;" +
"Ljava/lang/Object;I)Ljava/lang/Object;";
cfw.addInvoke(ByteCode.INVOKESTATIC,
mainClassName,
getBodyMethodName(n) + "_gen",
type);
cfw.add(ByteCode.ARETURN);
} else {
cfw.add(ByteCode.GOTO, endlabel);
}
}
cfw.markLabel(endlabel);
pushUndefined(cfw);
cfw.add(ByteCode.ARETURN);
// this method uses as many locals as there are arguments (hence 6)
cfw.stopMethod((short)6);
}
private void generateCallMethod(ClassFileWriter cfw, boolean isStrictMode)
{
cfw.startMethod("call",
"(Lorg/mozilla/javascript/Context;" +
"Lorg/mozilla/javascript/Scriptable;" +
"Lorg/mozilla/javascript/Scriptable;" +
"[Ljava/lang/Object;)Ljava/lang/Object;",
(short)(ACC_PUBLIC | ACC_FINAL));
// Generate code for:
// if (!ScriptRuntime.hasTopCall(cx)) {
// return ScriptRuntime.doTopCall(this, cx, scope, thisObj, args);
// }
int nonTopCallLabel = cfw.acquireLabel();
cfw.addALoad(1); //cx
cfw.addInvoke(ByteCode.INVOKESTATIC,
"org/mozilla/javascript/ScriptRuntime",
"hasTopCall",
"(Lorg/mozilla/javascript/Context;"
+")Z");
cfw.add(ByteCode.IFNE, nonTopCallLabel);
cfw.addALoad(0);
cfw.addALoad(1);
cfw.addALoad(2);
cfw.addALoad(3);
cfw.addALoad(4);
cfw.addPush(isStrictMode);
cfw.addInvoke(ByteCode.INVOKESTATIC,
"org/mozilla/javascript/ScriptRuntime",
"doTopCall",
"(Lorg/mozilla/javascript/Callable;"
+"Lorg/mozilla/javascript/Context;"
+"Lorg/mozilla/javascript/Scriptable;"
+"Lorg/mozilla/javascript/Scriptable;"
+"[Ljava/lang/Object;"
+"Z"
+")Ljava/lang/Object;");
cfw.add(ByteCode.ARETURN);
cfw.markLabel(nonTopCallLabel);
// Now generate switch to call the real methods
cfw.addALoad(0);
cfw.addALoad(1);
cfw.addALoad(2);
cfw.addALoad(3);
cfw.addALoad(4);
int end = scriptOrFnNodes.length;
boolean generateSwitch = (2 <= end);
int switchStart = 0;
int switchStackTop = 0;
if (generateSwitch) {
cfw.addLoadThis();
cfw.add(ByteCode.GETFIELD, cfw.getClassName(), ID_FIELD_NAME, "I");
// do switch from (1, end - 1) mapping 0 to
// the default case
switchStart = cfw.addTableSwitch(1, end - 1);
}
for (int i = 0; i != end; ++i) {
ScriptNode n = scriptOrFnNodes[i];
if (generateSwitch) {
if (i == 0) {
cfw.markTableSwitchDefault(switchStart);
switchStackTop = cfw.getStackTop();
} else {
cfw.markTableSwitchCase(switchStart, i - 1,
switchStackTop);
}
}
if (n.getType() == Token.FUNCTION) {
OptFunctionNode ofn = OptFunctionNode.get(n);
if (ofn.isTargetOfDirectCall()) {
int pcount = ofn.fnode.getParamCount();
if (pcount != 0) {
// loop invariant:
// stack top == arguments array from addALoad4()
for (int p = 0; p != pcount; ++p) {
cfw.add(ByteCode.ARRAYLENGTH);
cfw.addPush(p);
int undefArg = cfw.acquireLabel();
int beyond = cfw.acquireLabel();
cfw.add(ByteCode.IF_ICMPLE, undefArg);
// get array[p]
cfw.addALoad(4);
cfw.addPush(p);
cfw.add(ByteCode.AALOAD);
cfw.add(ByteCode.GOTO, beyond);
cfw.markLabel(undefArg);
pushUndefined(cfw);
cfw.markLabel(beyond);
// Only one push
cfw.adjustStackTop(-1);
cfw.addPush(0.0);
// restore invariant
cfw.addALoad(4);
}
}
}
}
cfw.addInvoke(ByteCode.INVOKESTATIC,
mainClassName,
getBodyMethodName(n),
getBodyMethodSignature(n));
cfw.add(ByteCode.ARETURN);
}
cfw.stopMethod((short)5);
// 5: this, cx, scope, js this, args[]
}
private void generateMain(ClassFileWriter cfw)
{
cfw.startMethod("main", "([Ljava/lang/String;)V",
(short)(ACC_PUBLIC | ACC_STATIC));
// load new ScriptImpl()
cfw.add(ByteCode.NEW, cfw.getClassName());
cfw.add(ByteCode.DUP);
cfw.addInvoke(ByteCode.INVOKESPECIAL, cfw.getClassName(),
"", "()V");
// load 'args'
cfw.add(ByteCode.ALOAD_0);
// Call mainMethodClass.main(Script script, String[] args)
cfw.addInvoke(ByteCode.INVOKESTATIC,
mainMethodClass,
"main",
"(Lorg/mozilla/javascript/Script;[Ljava/lang/String;)V");
cfw.add(ByteCode.RETURN);
// 1 = String[] args
cfw.stopMethod((short)1);
}
private static void generateExecute(ClassFileWriter cfw)
{
cfw.startMethod("exec",
"(Lorg/mozilla/javascript/Context;"
+"Lorg/mozilla/javascript/Scriptable;"
+")Ljava/lang/Object;",
(short)(ACC_PUBLIC | ACC_FINAL));
final int CONTEXT_ARG = 1;
final int SCOPE_ARG = 2;
cfw.addLoadThis();
cfw.addALoad(CONTEXT_ARG);
cfw.addALoad(SCOPE_ARG);
cfw.add(ByteCode.DUP);
cfw.add(ByteCode.ACONST_NULL);
cfw.addInvoke(ByteCode.INVOKEVIRTUAL,
cfw.getClassName(),
"call",
"(Lorg/mozilla/javascript/Context;"
+"Lorg/mozilla/javascript/Scriptable;"
+"Lorg/mozilla/javascript/Scriptable;"
+"[Ljava/lang/Object;"
+")Ljava/lang/Object;");
cfw.add(ByteCode.ARETURN);
// 3 = this + context + scope
cfw.stopMethod((short)3);
}
private static void generateScriptCtor(ClassFileWriter cfw)
{
cfw.startMethod("", "()V", ACC_PUBLIC);
cfw.addLoadThis();
cfw.addInvoke(ByteCode.INVOKESPECIAL, SUPER_CLASS_NAME,
"", "()V");
// set id to 0
cfw.addLoadThis();
cfw.addPush(0);
cfw.add(ByteCode.PUTFIELD, cfw.getClassName(), ID_FIELD_NAME, "I");
cfw.add(ByteCode.RETURN);
// 1 parameter = this
cfw.stopMethod((short)1);
}
private void generateFunctionConstructor(ClassFileWriter cfw)
{
final int SCOPE_ARG = 1;
final int CONTEXT_ARG = 2;
final int ID_ARG = 3;
cfw.startMethod("", FUNCTION_CONSTRUCTOR_SIGNATURE, ACC_PUBLIC);
cfw.addALoad(0);
cfw.addInvoke(ByteCode.INVOKESPECIAL, SUPER_CLASS_NAME,
"", "()V");
cfw.addLoadThis();
cfw.addILoad(ID_ARG);
cfw.add(ByteCode.PUTFIELD, cfw.getClassName(), ID_FIELD_NAME, "I");
cfw.addLoadThis();
cfw.addALoad(CONTEXT_ARG);
cfw.addALoad(SCOPE_ARG);
int start = (scriptOrFnNodes[0].getType() == Token.SCRIPT) ? 1 : 0;
int end = scriptOrFnNodes.length;
if (start == end) throw badTree();
boolean generateSwitch = (2 <= end - start);
int switchStart = 0;
int switchStackTop = 0;
if (generateSwitch) {
cfw.addILoad(ID_ARG);
// do switch from (start + 1, end - 1) mapping start to
// the default case
switchStart = cfw.addTableSwitch(start + 1, end - 1);
}
for (int i = start; i != end; ++i) {
if (generateSwitch) {
if (i == start) {
cfw.markTableSwitchDefault(switchStart);
switchStackTop = cfw.getStackTop();
} else {
cfw.markTableSwitchCase(switchStart, i - 1 - start,
switchStackTop);
}
}
OptFunctionNode ofn = OptFunctionNode.get(scriptOrFnNodes[i]);
cfw.addInvoke(ByteCode.INVOKESPECIAL,
mainClassName,
getFunctionInitMethodName(ofn),
FUNCTION_INIT_SIGNATURE);
cfw.add(ByteCode.RETURN);
}
// 4 = this + scope + context + id
cfw.stopMethod((short)4);
}
private void generateFunctionInit(ClassFileWriter cfw,
OptFunctionNode ofn)
{
final int CONTEXT_ARG = 1;
final int SCOPE_ARG = 2;
cfw.startMethod(getFunctionInitMethodName(ofn),
FUNCTION_INIT_SIGNATURE,
(short)(ACC_PRIVATE | ACC_FINAL));
// Call NativeFunction.initScriptFunction
cfw.addLoadThis();
cfw.addALoad(CONTEXT_ARG);
cfw.addALoad(SCOPE_ARG);
cfw.addInvoke(ByteCode.INVOKEVIRTUAL,
"org/mozilla/javascript/NativeFunction",
"initScriptFunction",
"(Lorg/mozilla/javascript/Context;"
+"Lorg/mozilla/javascript/Scriptable;"
+")V");
// precompile all regexp literals
if (ofn.fnode.getRegexpCount() != 0) {
cfw.addALoad(CONTEXT_ARG);
cfw.addInvoke(ByteCode.INVOKESTATIC, mainClassName,
REGEXP_INIT_METHOD_NAME, REGEXP_INIT_METHOD_SIGNATURE);
}
cfw.add(ByteCode.RETURN);
// 3 = (scriptThis/functionRef) + scope + context
cfw.stopMethod((short)3);
}
private void generateNativeFunctionOverrides(ClassFileWriter cfw,
String encodedSource)
{
// Override NativeFunction.getLanguageVersion() with
// public int getLanguageVersion() { return ; }
cfw.startMethod("getLanguageVersion", "()I", ACC_PUBLIC);
cfw.addPush(compilerEnv.getLanguageVersion());
cfw.add(ByteCode.IRETURN);
// 1: this and no argument or locals
cfw.stopMethod((short)1);
// The rest of NativeFunction overrides require specific code for each
// script/function id
final int Do_getFunctionName = 0;
final int Do_getParamCount = 1;
final int Do_getParamAndVarCount = 2;
final int Do_getParamOrVarName = 3;
final int Do_getEncodedSource = 4;
final int Do_getParamOrVarConst = 5;
final int Do_isGeneratorFunction = 6;
final int SWITCH_COUNT = 7;
for (int methodIndex = 0; methodIndex != SWITCH_COUNT; ++methodIndex) {
if (methodIndex == Do_getEncodedSource && encodedSource == null) {
continue;
}
// Generate:
// prologue;
// switch over function id to implement function-specific action
// epilogue
short methodLocals;
switch (methodIndex) {
case Do_getFunctionName:
methodLocals = 1; // Only this
cfw.startMethod("getFunctionName", "()Ljava/lang/String;",
ACC_PUBLIC);
break;
case Do_getParamCount:
methodLocals = 1; // Only this
cfw.startMethod("getParamCount", "()I",
ACC_PUBLIC);
break;
case Do_getParamAndVarCount:
methodLocals = 1; // Only this
cfw.startMethod("getParamAndVarCount", "()I",
ACC_PUBLIC);
break;
case Do_getParamOrVarName:
methodLocals = 1 + 1; // this + paramOrVarIndex
cfw.startMethod("getParamOrVarName", "(I)Ljava/lang/String;",
ACC_PUBLIC);
break;
case Do_getParamOrVarConst:
methodLocals = 1 + 1 + 1; // this + paramOrVarName
cfw.startMethod("getParamOrVarConst", "(I)Z",
ACC_PUBLIC);
break;
case Do_getEncodedSource:
methodLocals = 1; // Only this
cfw.startMethod("getEncodedSource", "()Ljava/lang/String;",
ACC_PUBLIC);
cfw.addPush(encodedSource);
break;
case Do_isGeneratorFunction:
methodLocals = 1; // Only this
cfw.startMethod("isGeneratorFunction", "()Z",
ACC_PROTECTED);
break;
default:
throw Kit.codeBug();
}
int count = scriptOrFnNodes.length;
int switchStart = 0;
int switchStackTop = 0;
if (count > 1) {
// Generate switch but only if there is more then one
// script/function
cfw.addLoadThis();
cfw.add(ByteCode.GETFIELD, cfw.getClassName(),
ID_FIELD_NAME, "I");
// do switch from 1 .. count - 1 mapping 0 to the default case
switchStart = cfw.addTableSwitch(1, count - 1);
}
for (int i = 0; i != count; ++i) {
ScriptNode n = scriptOrFnNodes[i];
if (i == 0) {
if (count > 1) {
cfw.markTableSwitchDefault(switchStart);
switchStackTop = cfw.getStackTop();
}
} else {
cfw.markTableSwitchCase(switchStart, i - 1,
switchStackTop);
}
// Impelemnet method-specific switch code
switch (methodIndex) {
case Do_getFunctionName:
// Push function name
if (n.getType() == Token.SCRIPT) {
cfw.addPush("");
} else {
String name = ((FunctionNode)n).getName();
cfw.addPush(name);
}
cfw.add(ByteCode.ARETURN);
break;
case Do_getParamCount:
// Push number of defined parameters
cfw.addPush(n.getParamCount());
cfw.add(ByteCode.IRETURN);
break;
case Do_getParamAndVarCount:
// Push number of defined parameters and declared variables
cfw.addPush(n.getParamAndVarCount());
cfw.add(ByteCode.IRETURN);
break;
case Do_getParamOrVarName:
// Push name of parameter using another switch
// over paramAndVarCount
int paramAndVarCount = n.getParamAndVarCount();
if (paramAndVarCount == 0) {
// The runtime should never call the method in this
// case but to make bytecode verifier happy return null
// as throwing execption takes more code
cfw.add(ByteCode.ACONST_NULL);
cfw.add(ByteCode.ARETURN);
} else if (paramAndVarCount == 1) {
// As above do not check for valid index but always
// return the name of the first param
cfw.addPush(n.getParamOrVarName(0));
cfw.add(ByteCode.ARETURN);
} else {
// Do switch over getParamOrVarName
cfw.addILoad(1); // param or var index
// do switch from 1 .. paramAndVarCount - 1 mapping 0
// to the default case
int paramSwitchStart = cfw.addTableSwitch(
1, paramAndVarCount - 1);
for (int j = 0; j != paramAndVarCount; ++j) {
if (cfw.getStackTop() != 0) Kit.codeBug();
String s = n.getParamOrVarName(j);
if (j == 0) {
cfw.markTableSwitchDefault(paramSwitchStart);
} else {
cfw.markTableSwitchCase(paramSwitchStart, j - 1,
0);
}
cfw.addPush(s);
cfw.add(ByteCode.ARETURN);
}
}
break;
case Do_getParamOrVarConst:
// Push name of parameter using another switch
// over paramAndVarCount
paramAndVarCount = n.getParamAndVarCount();
boolean [] constness = n.getParamAndVarConst();
if (paramAndVarCount == 0) {
// The runtime should never call the method in this
// case but to make bytecode verifier happy return null
// as throwing execption takes more code
cfw.add(ByteCode.ICONST_0);
cfw.add(ByteCode.IRETURN);
} else if (paramAndVarCount == 1) {
// As above do not check for valid index but always
// return the name of the first param
cfw.addPush(constness[0]);
cfw.add(ByteCode.IRETURN);
} else {
// Do switch over getParamOrVarName
cfw.addILoad(1); // param or var index
// do switch from 1 .. paramAndVarCount - 1 mapping 0
// to the default case
int paramSwitchStart = cfw.addTableSwitch(
1, paramAndVarCount - 1);
for (int j = 0; j != paramAndVarCount; ++j) {
if (cfw.getStackTop() != 0) Kit.codeBug();
if (j == 0) {
cfw.markTableSwitchDefault(paramSwitchStart);
} else {
cfw.markTableSwitchCase(paramSwitchStart, j - 1,
0);
}
cfw.addPush(constness[j]);
cfw.add(ByteCode.IRETURN);
}
}
break;
case Do_isGeneratorFunction:
// Push a boolean if it's a generator
if (n instanceof FunctionNode) {
cfw.addPush(((FunctionNode) n).isES6Generator());
} else {
cfw.addPush(false);
}
cfw.add(ByteCode.IRETURN);
break;
case Do_getEncodedSource:
// Push number encoded source start and end
// to prepare for encodedSource.substring(start, end)
cfw.addPush(n.getEncodedSourceStart());
cfw.addPush(n.getEncodedSourceEnd());
cfw.addInvoke(ByteCode.INVOKEVIRTUAL,
"java/lang/String",
"substring",
"(II)Ljava/lang/String;");
cfw.add(ByteCode.ARETURN);
break;
default:
throw Kit.codeBug();
}
}
cfw.stopMethod(methodLocals);
}
}
private void emitRegExpInit(ClassFileWriter cfw)
{
// precompile all regexp literals
int totalRegCount = 0;
for (int i = 0; i != scriptOrFnNodes.length; ++i) {
totalRegCount += scriptOrFnNodes[i].getRegexpCount();
}
if (totalRegCount == 0) {
return;
}
cfw.startMethod(REGEXP_INIT_METHOD_NAME, REGEXP_INIT_METHOD_SIGNATURE,
(short)(ACC_STATIC | ACC_PRIVATE));
cfw.addField("_reInitDone", "Z",
(short)(ACC_STATIC | ACC_PRIVATE | ACC_VOLATILE));
cfw.add(ByteCode.GETSTATIC, mainClassName, "_reInitDone", "Z");
int doInit = cfw.acquireLabel();
cfw.add(ByteCode.IFEQ, doInit);
cfw.add(ByteCode.RETURN);
cfw.markLabel(doInit);
// get regexp proxy and store it in local slot 1
cfw.addALoad(0); // context
cfw.addInvoke(ByteCode.INVOKESTATIC,
"org/mozilla/javascript/ScriptRuntime",
"checkRegExpProxy",
"(Lorg/mozilla/javascript/Context;"
+")Lorg/mozilla/javascript/RegExpProxy;");
cfw.addAStore(1); // proxy
// We could apply double-checked locking here but concurrency
// shouldn't be a problem in practice
for (int i = 0; i != scriptOrFnNodes.length; ++i) {
ScriptNode n = scriptOrFnNodes[i];
int regCount = n.getRegexpCount();
for (int j = 0; j != regCount; ++j) {
String reFieldName = getCompiledRegexpName(n, j);
String reFieldType = "Ljava/lang/Object;";
String reString = n.getRegexpString(j);
String reFlags = n.getRegexpFlags(j);
cfw.addField(reFieldName, reFieldType,
(short)(ACC_STATIC | ACC_PRIVATE));
cfw.addALoad(1); // proxy
cfw.addALoad(0); // context
cfw.addPush(reString);
if (reFlags == null) {
cfw.add(ByteCode.ACONST_NULL);
} else {
cfw.addPush(reFlags);
}
cfw.addInvoke(ByteCode.INVOKEINTERFACE,
"org/mozilla/javascript/RegExpProxy",
"compileRegExp",
"(Lorg/mozilla/javascript/Context;"
+"Ljava/lang/String;Ljava/lang/String;"
+")Ljava/lang/Object;");
cfw.add(ByteCode.PUTSTATIC, mainClassName,
reFieldName, reFieldType);
}
}
cfw.addPush(1);
cfw.add(ByteCode.PUTSTATIC, mainClassName, "_reInitDone", "Z");
cfw.add(ByteCode.RETURN);
cfw.stopMethod((short)2);
}
private void emitConstantDudeInitializers(ClassFileWriter cfw)
{
int N = itsConstantListSize;
if (N == 0)
return;
cfw.startMethod("", "()V", (short)(ACC_STATIC | ACC_FINAL));
double[] array = itsConstantList;
for (int i = 0; i != N; ++i) {
double num = array[i];
String constantName = "_k" + i;
String constantType = getStaticConstantWrapperType(num);
cfw.addField(constantName, constantType,
(short)(ACC_STATIC | ACC_PRIVATE));
int inum = (int)num;
if (inum == num) {
cfw.addPush(inum);
cfw.addInvoke(ByteCode.INVOKESTATIC, "java/lang/Integer",
"valueOf", "(I)Ljava/lang/Integer;");
} else {
cfw.addPush(num);
addDoubleWrap(cfw);
}
cfw.add(ByteCode.PUTSTATIC, mainClassName,
constantName, constantType);
}
cfw.add(ByteCode.RETURN);
cfw.stopMethod((short)0);
}
void pushNumberAsObject(ClassFileWriter cfw, double num)
{
if (num == 0.0) {
if (1 / num > 0) {
// +0.0
cfw.add(ByteCode.GETSTATIC,
"org/mozilla/javascript/ScriptRuntime",
"zeroObj", "Ljava/lang/Double;");
} else {
cfw.addPush(num);
addDoubleWrap(cfw);
}
} else if (num == 1.0) {
cfw.add(ByteCode.GETSTATIC,
"org/mozilla/javascript/optimizer/OptRuntime",
"oneObj", "Ljava/lang/Double;");
return;
} else if (num == -1.0) {
cfw.add(ByteCode.GETSTATIC,
"org/mozilla/javascript/optimizer/OptRuntime",
"minusOneObj", "Ljava/lang/Double;");
} else if (Double.isNaN(num)) {
cfw.add(ByteCode.GETSTATIC,
"org/mozilla/javascript/ScriptRuntime",
"NaNobj", "Ljava/lang/Double;");
} else if (itsConstantListSize >= 2000) {
// There appears to be a limit in the JVM on either the number
// of static fields in a class or the size of the class
// initializer. Either way, we can't have any more than 2000
// statically init'd constants.
cfw.addPush(num);
addDoubleWrap(cfw);
} else {
int N = itsConstantListSize;
int index = 0;
if (N == 0) {
itsConstantList = new double[64];
} else {
double[] array = itsConstantList;
while (index != N && array[index] != num) {
++index;
}
if (N == array.length) {
array = new double[N * 2];
System.arraycopy(itsConstantList, 0, array, 0, N);
itsConstantList = array;
}
}
if (index == N) {
itsConstantList[N] = num;
itsConstantListSize = N + 1;
}
String constantName = "_k" + index;
String constantType = getStaticConstantWrapperType(num);
cfw.add(ByteCode.GETSTATIC, mainClassName,
constantName, constantType);
}
}
private static void addDoubleWrap(ClassFileWriter cfw)
{
cfw.addInvoke(ByteCode.INVOKESTATIC,
"org/mozilla/javascript/optimizer/OptRuntime",
"wrapDouble", "(D)Ljava/lang/Double;");
}
private static String getStaticConstantWrapperType(double num)
{
int inum = (int)num;
if (inum == num) {
return "Ljava/lang/Integer;";
}
return "Ljava/lang/Double;";
}
static void pushUndefined(ClassFileWriter cfw)
{
cfw.add(ByteCode.GETSTATIC, "org/mozilla/javascript/Undefined",
"instance", "Ljava/lang/Object;");
}
int getIndex(ScriptNode n)
{
return scriptOrFnIndexes.getExisting(n);
}
String getDirectCtorName(ScriptNode n)
{
return "_n" + getIndex(n);
}
String getBodyMethodName(ScriptNode n)
{
return "_c_" + cleanName(n) + "_" + getIndex(n);
}
/**
* Gets a Java-compatible "informative" name for the the ScriptOrFnNode
*/
String cleanName(final ScriptNode n)
{
String result = "";
if (n instanceof FunctionNode) {
Name name = ((FunctionNode) n).getFunctionName();
if (name == null) {
result = "anonymous";
} else {
result = name.getIdentifier();
}
} else {
result = "script";
}
return result;
}
String getBodyMethodSignature(ScriptNode n)
{
StringBuilder sb = new StringBuilder();
sb.append('(');
sb.append(mainClassSignature);
sb.append("Lorg/mozilla/javascript/Context;"
+"Lorg/mozilla/javascript/Scriptable;"
+"Lorg/mozilla/javascript/Scriptable;");
if (n.getType() == Token.FUNCTION) {
OptFunctionNode ofn = OptFunctionNode.get(n);
if (ofn.isTargetOfDirectCall()) {
int pCount = ofn.fnode.getParamCount();
for (int i = 0; i != pCount; i++) {
sb.append("Ljava/lang/Object;D");
}
}
}
sb.append("[Ljava/lang/Object;)Ljava/lang/Object;");
return sb.toString();
}
String getFunctionInitMethodName(OptFunctionNode ofn)
{
return "_i"+getIndex(ofn.fnode);
}
String getCompiledRegexpName(ScriptNode n, int regexpIndex)
{
return "_re"+getIndex(n)+"_"+regexpIndex;
}
static RuntimeException badTree()
{
throw new RuntimeException("Bad tree in codegen");
}
public void setMainMethodClass(String className)
{
mainMethodClass = className;
}
static final String DEFAULT_MAIN_METHOD_CLASS
= "org.mozilla.javascript.optimizer.OptRuntime";
private static final String SUPER_CLASS_NAME
= "org.mozilla.javascript.NativeFunction";
static final String ID_FIELD_NAME = "_id";
static final String REGEXP_INIT_METHOD_NAME = "_reInit";
static final String REGEXP_INIT_METHOD_SIGNATURE
= "(Lorg/mozilla/javascript/Context;)V";
static final String FUNCTION_INIT_SIGNATURE
= "(Lorg/mozilla/javascript/Context;"
+"Lorg/mozilla/javascript/Scriptable;"
+")V";
static final String FUNCTION_CONSTRUCTOR_SIGNATURE
= "(Lorg/mozilla/javascript/Scriptable;"
+"Lorg/mozilla/javascript/Context;I)V";
private static final Object globalLock = new Object();
private static int globalSerialClassCounter;
private CompilerEnvirons compilerEnv;
private ObjArray directCallTargets;
ScriptNode[] scriptOrFnNodes;
private ObjToIntMap scriptOrFnIndexes;
private String mainMethodClass = DEFAULT_MAIN_METHOD_CLASS;
String mainClassName;
String mainClassSignature;
private double[] itsConstantList;
private int itsConstantListSize;
}
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