Created
May 27, 2012 00:25
-
-
Save FlightOfStairs/2795738 to your computer and use it in GitHub Desktop.
ASM bytecode transformation to identify concrete class at runtime
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
package org.flightofstairs.honours.capture.agent | |
import org.flightofstairs.honours.common.Call | |
import org.objectweb.asm.MethodVisitor | |
import org.objectweb.asm.Opcodes | |
import org.objectweb.asm.Type | |
import org.slf4j.LoggerFactory | |
import org.objectweb.asm.tree.* | |
import org.objectweb.asm.tree.analysis.* | |
class MethodWeaver extends MethodNode implements Opcodes { | |
private final String owner | |
private final MethodVisitor mv | |
private final ArrayList<MethodInsnNode> calls = new ArrayList<MethodInsnNode>(); | |
MethodWeaver(String owner, int access, String name, String desc, | |
String signature, String[] exceptions, MethodVisitor mv) { | |
super(access, name, desc, signature, exceptions); | |
this.owner = owner; | |
this.mv = mv; | |
} | |
@Override | |
void visitMethodInsn(final int opcode, final String owner, final String name, final String desc) { | |
if(opcode == INVOKEVIRTUAL) { | |
int probeID = Tracer.INSTANCE.probes.createProbeIDAt(new Call(owner, name, desc)) | |
super.visitFieldInsn(GETSTATIC, "org/flightofstairs/honours/capture/agent/Tracer", "INSTANCE", "Lorg/flightofstairs/honours/capture/agent/Tracer;") | |
super.visitLdcInsn(probeID) | |
super.visitMethodInsn(INVOKEVIRTUAL, "org/flightofstairs/honours/capture/agent/Tracer", "probe", "(I)V") | |
} | |
super.visitMethodInsn(opcode, owner, name, desc); | |
if(opcode==INVOKEINTERFACE) { | |
calls.add((MethodInsnNode) instructions.getLast()); | |
} | |
} | |
@Override | |
public void visitMaxs(int maxStack, int maxLocals) { | |
super.visitMaxs(maxStack + 5 * calls.size(), maxLocals) | |
} | |
@Override | |
public void visitEnd() { | |
if(!calls.isEmpty()) { | |
try { | |
List<AbstractInsnNode> objectRefLoadPoints = [] | |
Analyzer analyzer = new Analyzer(new SourceInterpreter()) | |
Frame[] frames = analyzer.analyze(owner, this) as Frame[] | |
for (MethodInsnNode methodInsnNode : calls) { | |
Frame frame = frames[instructions.indexOf(methodInsnNode)] | |
if(frame == null) continue | |
int stackSlot = frame.getStackSize() - 1 | |
for(Type type : Type.getArgumentTypes(methodInsnNode.desc)) { | |
stackSlot -= type.getSize() | |
} | |
SourceValue stackValue = (SourceValue) frame.getStack(stackSlot) | |
objectRefLoadPoints.addAll stackValue.insns | |
} | |
for(AbstractInsnNode node : objectRefLoadPoints) { | |
instructions.insert(node, traceInstructions(owner, "lol")) | |
} | |
} catch (AnalyzerException ex) { | |
LoggerFactory.getLogger(getClass()).warn("Error instrumenting method: {} {}", owner, name, ex) | |
} | |
} | |
accept(mv) | |
LoggerFactory.getLogger(getClass()).trace("Instrumented method: {} {}", owner, name) | |
} | |
private static InsnList traceInstructions(String owner, String method) { | |
InsnList list = new InsnList(); | |
list.add(new InsnNode(Opcodes.DUP)) | |
list.add(new MethodInsnNode(Opcodes.INVOKEVIRTUAL, "java/lang/Object", "getClass", "()Ljava/lang/Class;")) | |
list.add(new FieldInsnNode(Opcodes.GETSTATIC, "org/flightofstairs/honours/capture/agent/Tracer", "INSTANCE", "Lorg/flightofstairs/honours/capture/agent/Tracer;")) | |
list.add(new InsnNode(Opcodes.SWAP)) | |
list.add(new LdcInsnNode(owner)) | |
list.add(new LdcInsnNode(method)) | |
list.add(new MethodInsnNode(Opcodes.INVOKEVIRTUAL, "org/flightofstairs/honours/capture/agent/Tracer", "probe", "(Ljava/lang/Class;Ljava/lang/String;Ljava/lang/String;)V")) | |
return list | |
} | |
} |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment