Examples with MethodContext net.runelite.asm.execution.MethodContext used on opensource projects

Example 1 with MethodContext

use of net.runelite.asm.execution.MethodContext in project runelite by runelite.

the class ScriptVM method injectScriptVMHooks.

private void injectScriptVMHooks() throws InjectionException {
    /*
			This hooks local variable assignments in the copied version of runScript:
			 - The currently executing script > client.currentScript
			 - The currently executing script's program counter > client.currentScriptPC
			 - The currently executing opcode > client.vmExecuteOpcode(I)Z

			The currently executing script variable is located as the outermost Script local

			The PC is located by its use in PutField ScriptState::invokedFromPC

			The currently executing opcode is found by searching for iaload with the script's instruction array

			The script's instruction array is identified by looking for the getfield from script.instructions

			bn.g @ rev 163 :
			// Jump back to here if vmExecuteOpcode returns true
			aload6 // Script.instructions
			iinc 5 1 // ++PC
			iload5 // PC
			iaload
			istore8
			// <- Inject here
			iload8
			bipush 100
			if_icmpge L52

		 */
    String scriptObName = DeobAnnotations.getObfuscatedName(inject.getDeobfuscated().findClass("Script").getAnnotations());
    Method runScript = findObMethod("copy$runScript");
    Method vmExecuteOpcode = findObMethod("vmExecuteOpcode");
    Field scriptInstructions = findDeobField("instructions");
    Field scriptStatePC = findDeobField("invokedFromPc");
    Field currentScriptField = findObField("currentScript");
    Field currentScriptPCField = findObField("currentScriptPC");
    Execution e = new Execution(inject.getVanilla());
    e.addMethod(runScript);
    e.noInvoke = true;
    AtomicReference<MethodContext> pcontext = new AtomicReference<>(null);
    e.addMethodContextVisitor(pcontext::set);
    e.run();
    Instructions instrs = runScript.getCode().getInstructions();
    Set<AStore> scriptStores = new HashSet<>();
    Integer pcLocalVar = null;
    Integer instructionArrayLocalVar = null;
    IStore currentOpcodeStore = null;
    ALoad localInstructionLoad = null;
    MethodContext methodContext = pcontext.get();
    for (InstructionContext instrCtx : methodContext.getInstructionContexts()) {
        Instruction instr = instrCtx.getInstruction();
        if (instr instanceof AStore) {
            AStore store = (AStore) instr;
            StackContext storedVarCtx = instrCtx.getPops().get(0);
            // Find AStores that store a Script
            if (storedVarCtx.getType().getInternalName().equals(scriptObName)) {
                scriptStores.add(store);
            }
            // Find AStores that store the instructions
            InstructionContext pusherCtx = storedVarCtx.getPushed();
            if (pusherCtx.getInstruction() instanceof GetField) {
                GetField getField = (GetField) pusherCtx.getInstruction();
                if (getField.getMyField().equals(scriptInstructions)) {
                    instructionArrayLocalVar = store.getVariableIndex();
                }
            }
        }
        // Find the local that invokedFromPc is set from
        if (instr instanceof PutField) {
            PutField put = (PutField) instr;
            if (put.getMyField() == scriptStatePC) {
                StackContext pc = instrCtx.getPops().get(0);
                assert Type.INT.equals(pc.getType()) : pc.getType();
                InstructionContext mulctx = pc.pushed;
                assert mulctx.getInstruction() instanceof IMul;
                pcLocalVar = mulctx.getPops().stream().map(StackContext::getPushed).filter(i -> i.getInstruction() instanceof ILoad).map(i -> ((ILoad) i.getInstruction()).getVariableIndex()).findFirst().orElse(null);
            }
        }
    }
    // This has to run after the first loop because it relies on instructionArrayLocalVar being set
    if (instructionArrayLocalVar == null) {
        throw new InjectionException("Unable to find local instruction array");
    }
    for (InstructionContext instrCtx : methodContext.getInstructionContexts()) {
        Instruction instr = instrCtx.getInstruction();
        if (instr instanceof IALoad) {
            StackContext array = instrCtx.getPops().get(1);
            // Check where the array came from (looking for a getField scriptInstructions
            InstructionContext pushedCtx = array.getPushed();
            Instruction pushed = pushedCtx.getInstruction();
            if (pushed instanceof ALoad) {
                ALoad arrayLoad = (ALoad) pushed;
                if (arrayLoad.getVariableIndex() == instructionArrayLocalVar) {
                    // Find the istore
                    IStore istore = (IStore) instrCtx.getPushes().get(0).getPopped().stream().map(InstructionContext::getInstruction).filter(i -> i instanceof IStore).findFirst().orElse(null);
                    if (istore != null) {
                        currentOpcodeStore = istore;
                        localInstructionLoad = arrayLoad;
                    }
                }
            }
        }
    }
    // Add PutStatics to all Script AStores
    {
        int outerSciptIdx = scriptStores.stream().mapToInt(AStore::getVariableIndex).reduce(Math::min).orElseThrow(() -> new InjectionException("Unable to find any Script AStores in runScript"));
        log.debug("Found script index {}", outerSciptIdx);
        ListIterator<Instruction> instrIter = instrs.getInstructions().listIterator();
        while (instrIter.hasNext()) {
            Instruction instr = instrIter.next();
            if (instr instanceof AStore) {
                AStore il = (AStore) instr;
                if (il.getVariableIndex() == outerSciptIdx) {
                    instrIter.previous();
                    instrIter.add(new Dup(instrs));
                    instrIter.add(new PutStatic(instrs, currentScriptField));
                    instrIter.next();
                }
            }
        }
    }
    // Add PutStatics to all PC IStores and IIncs
    {
        if (pcLocalVar == null) {
            throw new InjectionException("Unable to find ILoad for invokedFromPc IStore");
        }
        log.debug("Found pc index {}", pcLocalVar);
        ListIterator<Instruction> instrIter = instrs.getInstructions().listIterator();
        while (instrIter.hasNext()) {
            Instruction instr = instrIter.next();
            if (instr instanceof IStore) {
                IStore il = (IStore) instr;
                if (il.getVariableIndex() == pcLocalVar) {
                    instrIter.previous();
                    instrIter.add(new Dup(instrs));
                    instrIter.add(new PutStatic(instrs, currentScriptPCField));
                    instrIter.next();
                }
            }
            if (instr instanceof IInc) {
                IInc iinc = (IInc) instr;
                if (iinc.getVariableIndex() == pcLocalVar) {
                    instrIter.add(new ILoad(instrs, pcLocalVar));
                    instrIter.add(new PutStatic(instrs, currentScriptPCField));
                }
            }
        }
    }
    // Inject call to vmExecuteOpcode
    log.debug("Found instruction array index {}", instructionArrayLocalVar);
    if (currentOpcodeStore == null) {
        throw new InjectionException("Unable to find IStore for current opcode");
    }
    int istorepc = instrs.getInstructions().indexOf(currentOpcodeStore);
    assert istorepc >= 0;
    Label nextIteration = instrs.createLabelFor(localInstructionLoad);
    instrs.addInstruction(istorepc + 1, new ILoad(instrs, currentOpcodeStore.getVariableIndex()));
    instrs.addInstruction(istorepc + 2, new InvokeStatic(instrs, vmExecuteOpcode.getPoolMethod()));
    instrs.addInstruction(istorepc + 3, new IfNe(instrs, nextIteration));
}