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much better this is

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Shautvast 2024-06-23 18:24:24 +02:00
parent 8f516d5612
commit b3f9ac503c
1 changed files with 41 additions and 53 deletions
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72
agent/src/main/java/com/github/shautvast/exceptional/Agent.java
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@ -3,15 +3,19 @@ package com.github.shautvast.exceptional;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.lang.classfile.*;
import java.lang.classfile.ClassElement;
import java.lang.classfile.ClassFile;
import java.lang.classfile.ClassModel;
import java.lang.classfile.MethodModel;
import java.lang.classfile.instruction.ReturnInstruction;
import java.lang.constant.ClassDesc;
import java.lang.constant.ConstantDescs;
import java.lang.constant.MethodTypeDesc;
import java.lang.instrument.ClassDefinition;
import java.lang.instrument.ClassFileTransformer;
import java.lang.instrument.IllegalClassFormatException;
import java.lang.instrument.Instrumentation;
import java.lang.reflect.Modifier;
import java.nio.file.Files;
import java.nio.file.Path;
import java.security.ProtectionDomain;
@SuppressWarnings("ALL")
@ -54,43 +58,36 @@ public class Agent {
if (className.equals("java/lang/Throwable")) {
ClassFile classFile = ClassFile.of();
ClassModel classModel = classFile.parse(classfileBuffer);
byte[] bytes = instrumentByteCode(classFile, classModel);
try {
Files.write(Path.of("MyThrowable.class"), bytes);
} catch (IOException e) {
throw new RuntimeException(e);
}
return bytes;
} else {
return classfileBuffer;
}
}
private static byte[] instrumentByteCode(ClassFile classFile, ClassModel classModel) {
return classFile.build(classModel.thisClass().asSymbol(), classBuilder -> {
for (ClassElement ce : classModel) {
if (ce instanceof MethodModel mm) {
String signature = mm.methodName() + mm.methodType().stringValue();
if (signature.equals("<init>()V")) {
classBuilder.withMethod(mm.methodName(), mm.methodType(), Modifier.PUBLIC,
methodBuilder -> methodBuilder.withCode(
cb -> {
// recreate existing code for this method, because... I don't know how to simply add the new code at the end🫣
ClassDesc throwable = ClassDesc.of("java.lang.Throwable");
cb.aload(0);
cb.invokespecial(ConstantDescs.CD_Object, "<init>", MethodTypeDesc.ofDescriptor("()V"));
cb.aload(0);
cb.aload(0);
cb.putfield(throwable, "cause", ClassDesc.ofDescriptor("Ljava/lang/Throwable;"));
cb.aload(0);
cb.getstatic(throwable, "UNASSIGNED_STACK", ClassDesc.ofDescriptor("[Ljava/lang/StackTraceElement;"));
cb.putfield(throwable, "stackTrace", ClassDesc.ofDescriptor("[Ljava/lang/StackTraceElement;"));
cb.aload(0);
cb.invokevirtual(throwable, "fillInStackTrace", MethodTypeDesc.ofDescriptor("()Ljava/lang/Throwable;"));
cb.pop();
// cb.getstatic(throwable, "jfrTracing", ConstantDescs.CD_Boolean);
// Label end = cb.newLabel();
// cb.ifeq(end);
// cb.aload(0);
// cb.invokevirtual(ConstantDescs.CD_Object, "getClass", MethodTypeDesc.ofDescriptor("()Ljava/lang/Class;"));
// cb.aconst_null();
// cb.invokestatic(ClassDesc.of("jdk.internal.event.ThrowableTracer"), "traceThrowable", MethodTypeDesc.ofDescriptor("(Ljava/lang/Class;Ljava/lang/String;)V"));
// cb.labelBinding(end);
cb.aload(0);
cb.invokestatic(
if (mm.methodName().toString().equals("<init>")) {
classBuilder.withMethod(mm.methodName(), mm.methodType(), mm.flags().flagsMask(),
methodBuilder ->
methodBuilder.transformCode(mm.code().get(), ((builder, element) -> {
if (element instanceof ReturnInstruction) {
builder.aload(0);
builder.invokestatic(
ClassDesc.of("com.github.shautvast.exceptional.ThrowableHandler"), "handle",
MethodTypeDesc.ofDescriptor("(Ljava/lang/Throwable;)V"));
cb.return_();
builder.return_();
} else {
builder.with(element);
}
})
));
continue;
}
@ -98,14 +95,5 @@ public class Agent {
classBuilder.with(ce);
}
});
} else {
return classfileBuffer;
}
}
}
//getstatic #7 // Field java/lang/System.out:Ljava/io/PrintStream;
//ldc #13 // class com/github/shautvast/exceptional/Foo
//invokevirtual #15 // Method java/lang/Class.getModule:()Ljava/lang/Module;
//invokevirtual #21 // Method java/lang/Module.getName:()Ljava/lang/String;
//invokevirtual #27 // Method java/io/PrintStream.println:(Ljava/lang/String;)V