I'm fighting with ASM since 5 days and I can't get with the solution to my problem. The requirement is to get all values passed as argumentsfrom a method call. I know that there are a lot of tools to accomplish this. I went for ASM (I don't know if I took the right decision)
For example, if I have these methods
public void test2(String a, int b , String c, boolean ba, long d, String e){
}
public String giveMeAString(){
return "oneString";
}
public String giveMeAnotherString(){
return "anotherString";
}
public void test(){
test2("firstParameter", 2907, giveMeAString(),true, 1992, giveMeAnotherString());
}
I would like to save ["firstParameter",2907, "oneString", true, 1992, "anotherString"]
I have already read these topics:
How to get the return value in asm?
Java method parameters values in ASM
Tracing method invocation arguments in bytecode using ASM
get function arguments values using java asm for bytecode instrimentation
Which explain about putting the arguments to the local variables, but how can I access them?
How can I obtain the VALUES of that arguments? I don't understand how can I get that args to.. I dont know, print them for example. Any idea? Once they are in the stack, i dont understand how can copy the value to a variable.
Thank you !
Here is the code that I'm using:
public static class ClassPrinterVisitor extends ClassVisitor {
private String name;
private String desc;
private String signature;
private Type[] paramTypes;
private boolean isStatic;
private String className;
private String methodName;
private String methodDesc;
private String owner;
private int access;
public ClassPrinterVisitor(int api, ClassVisitor cv) {
super(api, cv);
}
public ClassPrinterVisitor(int api) {
super(api);
}
@Override
public MethodVisitor visitMethod(int access, String name, String desc,
String signature, String[] exceptions) {
MethodVisitor oriMv = new MethodVisitor(Opcodes.ASM4) {
};
final MethodVisitor instMv2 = new MethodPrinterVisitor(access, desc, oriMv, Type.getArgumentTypes(desc), (access & Opcodes.ACC_STATIC) != 0, className,
name, desc);
return instMv2;
}
private class MethodPrinterVisitor extends MethodVisitor {
List<Object> params = new ArrayList<>();
List<Object> params2 = new ArrayList<>();
private Type[] paramTypes;
private boolean isStatic;
private String className;
private String methodName;
private String methodDesc;
public MethodPrinterVisitor(int api, MethodVisitor mv) {
super(api, mv);
}
public MethodPrinterVisitor(int access, String desc, MethodVisitor mv, Type[] paramTypes, boolean isStatic, String classname,
String methodname, String methoddesc) {
super(Opcodes.ASM4, mv);
this.paramTypes = paramTypes;
this.isStatic = isStatic;
this.className = classname;
this.methodName = methodname;
this.methodDesc = methoddesc;
}
@Override
public void visitLdcInsn(Object var1) {
if (var1 != null) {
params.add(var1);
super.visitLdcInsn(var1);
System.out.printf("arg: %s %n", var1.toString());
}
}
@Override
public void visitInsn(int var1) {
if(this.mv != null) {
this.mv.visitInsn(var1);
}
}
@Override
public void visitIntInsn(int var1, int var2) {
if(this.mv != null) {
this.mv.visitIntInsn(var1, var2);
}
}
@Override
public void visitVarInsn(int var1, int var2) {
if(this.mv != null) {
this.mv.visitVarInsn(var1, var2);
}
}
@Override
public void visitMethodInsn(int opcode, String owner, String name, String desc) {
Pattern pattern = Pattern.compile("[a-zA-Z0-9._]*");
System.out.printf("---------------------------%n");
System.out.printf("Class %s calls method %s from class %s%n", ClassPrinterVisitor.this.name, name, owner);
System.out.printf("Desc: %s signature: %s%n", ClassPrinterVisitor.this.desc, ClassPrinterVisitor.this.signature);
for (Object p : params) {
Matcher matcher = pattern.matcher(p.toString());
if (!p.toString().isEmpty() && !p.toString().startsWith(".") && matcher.matches()) {
System.out.printf("visitLdcInsn: %s %n", p);
}
}
System.out.printf("---------------------------%n%n");
params = new ArrayList<>();
}
@Override
public void visitCode() {
int paramLength = paramTypes.length;
// Create array with length equal to number of parameters
mv.visitIntInsn(Opcodes.BIPUSH, paramLength);
mv.visitTypeInsn(Opcodes.ANEWARRAY, "java/lang/Object");
mv.visitVarInsn(Opcodes.ASTORE, paramLength);
// Fill the created array with method parameters
int i = 0;
for (Type tp : paramTypes) {
mv.visitVarInsn(Opcodes.ALOAD, paramLength);
mv.visitIntInsn(Opcodes.BIPUSH, i);
if (tp.equals(Type.BOOLEAN_TYPE)) {
mv.visitVarInsn(Opcodes.ILOAD, i);
mv.visitMethodInsn(Opcodes.INVOKESTATIC, "java/lang/Boolean", "valueOf", "(Z)Ljava/lang/Boolean;");
} else if (tp.equals(Type.BYTE_TYPE)) {
mv.visitVarInsn(Opcodes.ILOAD, i);
mv.visitMethodInsn(Opcodes.INVOKESTATIC, "java/lang/Byte", "valueOf", "(B)Ljava/lang/Byte;");
} else if (tp.equals(Type.CHAR_TYPE)) {
mv.visitVarInsn(Opcodes.ILOAD, i);
mv.visitMethodInsn(Opcodes.INVOKESTATIC, "java/lang/Character", "valueOf", "(C)Ljava/lang/Character;");
} else if (tp.equals(Type.SHORT_TYPE)) {
mv.visitVarInsn(Opcodes.ILOAD, i);
mv.visitMethodInsn(Opcodes.INVOKESTATIC, "java/lang/Short", "valueOf", "(S)Ljava/lang/Short;");
} else if (tp.equals(Type.INT_TYPE)) {
mv.visitVarInsn(Opcodes.ILOAD, i);
mv.visitMethodInsn(Opcodes.INVOKESTATIC, "java/lang/Integer", "valueOf", "(I)Ljava/lang/Integer;");
} else if (tp.equals(Type.LONG_TYPE)) {
mv.visitVarInsn(Opcodes.LLOAD, i);
mv.visitMethodInsn(Opcodes.INVOKESTATIC, "java/lang/Long", "valueOf", "(J)Ljava/lang/Long;");
i++;
} else if (tp.equals(Type.FLOAT_TYPE)) {
mv.visitVarInsn(Opcodes.FLOAD, i);
mv.visitMethodInsn(Opcodes.INVOKESTATIC, "java/lang/Float", "valueOf", "(F)Ljava/lang/Float;");
} else if (tp.equals(Type.DOUBLE_TYPE)) {
mv.visitVarInsn(Opcodes.DLOAD, i);
mv.visitMethodInsn(Opcodes.INVOKESTATIC, "java/lang/Double", "valueOf", "(D)Ljava/lang/Double;");
i++;
} else
mv.visitVarInsn(Opcodes.ALOAD, i);
mv.visitInsn(Opcodes.AASTORE);
i++;
}
// Load id, class name and method name
this.visitLdcInsn(new Integer(this.methodID));
this.visitLdcInsn(this.className);
this.visitLdcInsn(this.methodName);
// Load the array of parameters that we created
this.visitVarInsn(Opcodes.ALOAD, paramLength);
mv.visitMethodInsn(Opcodes.INVOKESTATIC, className, name, signature);
super.visitCode();
}
}
}
