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play.classloading.enhancers.LocalvariablesNamesEnhancer Maven / Gradle / Ivy
package play.classloading.enhancers;
import javassist.*;
import javassist.bytecode.*;
import play.Logger;
import play.classloading.ApplicationClasses.ApplicationClass;
import play.libs.F.T2;
import java.lang.reflect.Field;
import java.util.*;
/**
* Track names of local variables ...
*/
public class LocalvariablesNamesEnhancer extends Enhancer {
@Override
public void enhanceThisClass(ApplicationClass applicationClass) throws Exception {
if (isAnon(applicationClass)) {
return;
}
CtClass ctClass = makeClass(applicationClass);
if (!ctClass.subtypeOf(classPool.get(LocalVariablesSupport.class.getName())) && !ctClass.getName().matches("^controllers\\..*\\$class$")) {
return;
}
for (CtMethod method : ctClass.getDeclaredMethods()) {
if (method.getName().contains("$")) {
// Generated method, skip
continue;
}
// Signatures names
CodeAttribute codeAttribute = (CodeAttribute) method.getMethodInfo().getAttribute("Code");
if (codeAttribute == null || javassist.Modifier.isAbstract(method.getModifiers())) {
continue;
}
LocalVariableAttribute localVariableAttribute = (LocalVariableAttribute) codeAttribute.getAttribute("LocalVariableTable");
List> parameterNames = new ArrayList<>();
if (localVariableAttribute == null) {
if(method.getParameterTypes().length > 0)
continue;
} else {
if(localVariableAttribute.tableLength() < method.getParameterTypes().length + (Modifier.isStatic(method.getModifiers()) ? 0 : 1)) {
Logger.warn("weird: skipping method %s %s as its number of local variables is incorrect (lv=%s || lv.length=%s || params.length=%s || (isStatic? %s)", method.getReturnType().getName(), method.getLongName(), localVariableAttribute, localVariableAttribute != null ? localVariableAttribute.tableLength() : -1, method.getParameterTypes().length, Modifier.isStatic(method.getModifiers()));
}
for(int i=0; i(localVariableAttribute.startPc(i) + localVariableAttribute.index(i), localVariableAttribute.variableName(i)));
}
}
Collections.sort(parameterNames, new Comparator>() {
@Override
public int compare(T2 o1, T2 o2) {
return o1._1.compareTo(o2._1);
}
});
}
List names = new ArrayList<>();
for (int i = 0; i < method.getParameterTypes().length + (Modifier.isStatic(method.getModifiers()) ? 0 : 1); i++) {
if (localVariableAttribute == null) {
continue;
}
try {
String name = parameterNames.get(i)._2;
if (!"this".equals(name)) {
names.add(name);
}
} catch (Exception e) {
Logger.warn(e, "While applying localvariables to %s.%s, param %s", ctClass.getName(), method.getName(), i);
}
}
StringBuilder iv = new StringBuilder();
if (names.isEmpty()) {
iv.append("new String[0];");
} else {
iv.append("new String[] {");
for (Iterator i = names.iterator(); i.hasNext();) {
iv.append("\"");
String aliasedName = i.next();
if (aliasedName.contains("$")) {
aliasedName = aliasedName.substring(0, aliasedName.indexOf("$"));
}
iv.append(aliasedName);
iv.append("\"");
if (i.hasNext()) {
iv.append(",");
}
}
iv.append("};");
}
String sigField = "$" + method.getName() + LocalVariablesNamesTracer.computeMethodHash(method.getParameterTypes());
try { // #1198
ctClass.getDeclaredField(sigField);
} catch (NotFoundException nfe) {
CtField signature = CtField.make("public static String[] " + sigField + " = " + iv, ctClass);
ctClass.addField(signature);
}
if (localVariableAttribute == null || isScala(applicationClass)) {
continue;
}
// OK.
// Here after each local variable creation instruction,
// we insert a call to play.utils.LocalVariables.addVariable('var', var)
// without breaking everything...
for (int i = 0; i < localVariableAttribute.tableLength(); i++) {
// name of the local variable
String name = localVariableAttribute.getConstPool().getUtf8Info(localVariableAttribute.nameIndex(i));
// Normalize the variable name
// For several reasons, both variables name and name$1 will be aliased to name
String aliasedName = name;
if (aliasedName.contains("$")) {
aliasedName = aliasedName.substring(0, aliasedName.indexOf("$"));
}
if ("this".equals(name)) {
continue;
}
/* DEBUG
IO.write(ctClass.toBytecode(), new File("/tmp/lv_"+applicationClass.name+".class"));
ctClass.defrost();
*/
try {
// The instruction at which this local variable has been created
Integer pc = localVariableAttribute.startPc(i);
// Move to the next instruction (insertionPc)
CodeIterator codeIterator = codeAttribute.iterator();
codeIterator.move(pc);
pc = codeIterator.next();
Bytecode b = makeBytecodeForLVStore(method, localVariableAttribute.signature(i), name, localVariableAttribute.index(i));
codeIterator.insert(pc, b.get());
codeAttribute.setMaxStack(codeAttribute.computeMaxStack());
// Bon chaque instruction de cette méthode
while (codeIterator.hasNext()) {
int index = codeIterator.next();
int op = codeIterator.byteAt(index);
// DEBUG
// printOp(op);
int varNumber = -1;
// The variable changes
if (storeByCode.containsKey(op)) {
varNumber = storeByCode.get(op);
if (varNumber == -2) {
varNumber = codeIterator.byteAt(index + 1);
}
}
// Si c'est un store de la variable en cours d'examination
// et que c'est dans la frame d'utilisation de cette variable on trace l'affectation.
// (en fait la frame commence à localVariableAttribute.startPc(i)-1 qui est la première affectation
// mais aussi l'initialisation de la variable qui est deja tracé plus haut, donc on commence à localVariableAttribute.startPc(i))
if (varNumber == localVariableAttribute.index(i) && index < localVariableAttribute.startPc(i) + localVariableAttribute.codeLength(i)) {
b = makeBytecodeForLVStore(method, localVariableAttribute.signature(i), aliasedName, varNumber);
codeIterator.insertEx(b.get());
codeAttribute.setMaxStack(codeAttribute.computeMaxStack());
}
}
} catch (Exception e) {
// Well probably a compiled optimizer (I hope so)
}
}
// init variable tracer
method.insertBefore("play.classloading.enhancers.LocalvariablesNamesEnhancer.LocalVariablesNamesTracer.enter();");
method.insertAfter("play.classloading.enhancers.LocalvariablesNamesEnhancer.LocalVariablesNamesTracer.exit();", true);
}
// Done.
applicationClass.enhancedByteCode = ctClass.toBytecode();
ctClass.defrost();
}
private static Bytecode makeBytecodeForLVStore(CtMethod method, String sig, String name, int slot) {
Bytecode b = new Bytecode(method.getMethodInfo().getConstPool());
b.addLdc(name);
if("I".equals(sig) || "B".equals(sig) || "C".equals(sig) || "S".equals(sig) || "Z".equals(sig))
b.addIload(slot);
else if("F".equals(sig))
b.addFload(slot);
else if("J".equals(sig))
b.addLload(slot);
else if("D".equals(sig))
b.addDload(slot);
else
b.addAload(slot);
String localVarDescriptor = sig;
if(!"B".equals(sig) && !"C".equals(sig) && !"D".equals(sig) && !"F".equals(sig) &&
!"I".equals(sig) && !"J".equals(sig) && !"S".equals(sig) && !"Z".equals(sig))
localVarDescriptor = "Ljava/lang/Object;";
Logger.trace("for variable '%s' in slot=%s, sig was '%s' and is now '%s'", name, slot, sig, localVarDescriptor);
b.addInvokestatic("play.classloading.enhancers.LocalvariablesNamesEnhancer$LocalVariablesNamesTracer", "addVariable", "(Ljava/lang/String;"+localVarDescriptor+")V");
return b;
}
/**
* Mark class that need local variables tracking
*/
public interface LocalVariablesSupport {
}
/**
* Runtime part.
*/
public static class LocalVariablesNamesTracer {
public static Integer computeMethodHash(CtClass[] parameters) {
String[] names = new String[parameters.length];
for (int i = 0; i < parameters.length; i++) {
names[i] = parameters[i].getName();
}
return computeMethodHash(names);
}
public static Integer computeMethodHash(Class[] parameters) {
String[] names = new String[parameters.length];
for (int i = 0; i < parameters.length; i++) {
Class param = parameters[i];
names[i] = "";
if (param.isArray()) {
int level = 1;
param = param.getComponentType();
// Array of array
while (param.isArray()) {
level++;
param = param.getComponentType();
}
names[i] = param.getName();
for (int j = 0; j < level; j++) {
names[i] += "[]";
}
} else {
names[i] = param.getName();
}
}
return computeMethodHash(names);
}
public static Integer computeMethodHash(String[] parameters) {
StringBuilder buffer = new StringBuilder();
for (String param : parameters) {
buffer.append(param);
}
Integer hash = buffer.toString().hashCode();
if (hash < 0) {
return -hash;
}
return hash;
}
static final ThreadLocal>> localVariables = new ThreadLocal<>();
public static void checkEmpty() {
if (localVariables.get() != null && !localVariables.get().isEmpty()) {
Logger.error("LocalVariablesNamesTracer.checkEmpty, constraint violated (%s)", localVariables.get().size());
}
}
public static void clear() {
if (localVariables.get() != null) {
localVariables.set(null);
}
}
public static void enter() {
if (localVariables.get() == null) {
localVariables.set(new Stack>());
}
localVariables.get().push(new HashMap());
}
public static void exit() {
if (localVariables.get().isEmpty()) {
return;
}
localVariables.get().pop().clear();
}
public static Map locals() {
if (localVariables.get() != null && !localVariables.get().empty()) {
return localVariables.get().peek();
}
return new HashMap<>();
}
public static void addVariable(String name, Object o) {
locals().put(name, o);
}
public static void addVariable(String name, boolean b) {
locals().put(name, b);
}
public static void addVariable(String name, char c) {
locals().put(name, c);
}
public static void addVariable(String name, byte b) {
locals().put(name, b);
}
public static void addVariable(String name, double d) {
locals().put(name, d);
}
public static void addVariable(String name, float f) {
locals().put(name, f);
}
public static void addVariable(String name, int i) {
locals().put(name, i);
}
public static void addVariable(String name, long l) {
locals().put(name, l);
}
public static void addVariable(String name, short s) {
locals().put(name, s);
}
public static Map getLocalVariables() {
return locals();
}
public static List getAllLocalVariableNames(Object o) {
List allNames = new ArrayList<>();
for (String variable : getLocalVariables().keySet()) {
if (getLocalVariables().get(variable) == o) {
allNames.add(variable);
}
if (o != null && o instanceof Number && o.equals(getLocalVariables().get(variable))) {
allNames.add(variable);
}
}
return allNames;
}
public static Object getLocalVariable(String variable) {
return getLocalVariables().get(variable);
}
public static Stack> getLocalVariablesStateBeforeAwait() {
Stack> state = localVariables.get();
// must clear the ThreadLocal to prevent destroying the state when exit() is called due to continuations-suspend
localVariables.set(new Stack>());
return state;
}
public static void setLocalVariablesStateAfterAwait(Stack> state) {
if (state==null) {
state = new Stack<>();
}
localVariables.set( state );
}
}
private static final Map storeByCode = new HashMap<>();
/**
* Useful instructions
*/
static {
storeByCode.put(CodeIterator.ASTORE_0, 0);
storeByCode.put(CodeIterator.ASTORE_1, 1);
storeByCode.put(CodeIterator.ASTORE_2, 2);
storeByCode.put(CodeIterator.ASTORE_3, 3);
storeByCode.put(CodeIterator.ASTORE, -2);
storeByCode.put(CodeIterator.ISTORE_0, 0);
storeByCode.put(CodeIterator.ISTORE_1, 1);
storeByCode.put(CodeIterator.ISTORE_2, 2);
storeByCode.put(CodeIterator.ISTORE_3, 3);
storeByCode.put(CodeIterator.ISTORE, -2);
storeByCode.put(CodeIterator.IINC, -2);
storeByCode.put(CodeIterator.LSTORE_0, 0);
storeByCode.put(CodeIterator.LSTORE_1, 1);
storeByCode.put(CodeIterator.LSTORE_2, 2);
storeByCode.put(CodeIterator.LSTORE_3, 3);
storeByCode.put(CodeIterator.LSTORE, -2);
storeByCode.put(CodeIterator.FSTORE_0, 0);
storeByCode.put(CodeIterator.FSTORE_1, 1);
storeByCode.put(CodeIterator.FSTORE_2, 2);
storeByCode.put(CodeIterator.FSTORE_3, 3);
storeByCode.put(CodeIterator.FSTORE, -2);
storeByCode.put(CodeIterator.DSTORE_0, 0);
storeByCode.put(CodeIterator.DSTORE_1, 1);
storeByCode.put(CodeIterator.DSTORE_2, 2);
storeByCode.put(CodeIterator.DSTORE_3, 3);
storeByCode.put(CodeIterator.DSTORE, -2);
}
/**
* Debug utility. Display a byte code op as plain text.
*/
public static void printOp(int op) {
try {
for (Field f : Opcode.class.getDeclaredFields()) {
if (java.lang.reflect.Modifier.isStatic(f.getModifiers()) && java.lang.reflect.Modifier.isPublic(f.getModifiers()) && f.getInt(null) == op) {
System.out.println(op + " " + f.getName());
}
}
} catch (Exception e) {
}
}
}
