From f0eabb06190a8924a2d632cff90974a66289daf9 Mon Sep 17 00:00:00 2001 From: Graham Date: Mon, 27 Jan 2020 21:24:44 +0000 Subject: [PATCH] Add generic data flow analysis framework --- .../openrs2/deob/analysis/DataFlowAnalyzer.kt | 71 +++++++++++++++++++ 1 file changed, 71 insertions(+) create mode 100644 deob/src/main/java/dev/openrs2/deob/analysis/DataFlowAnalyzer.kt diff --git a/deob/src/main/java/dev/openrs2/deob/analysis/DataFlowAnalyzer.kt b/deob/src/main/java/dev/openrs2/deob/analysis/DataFlowAnalyzer.kt new file mode 100644 index 00000000..4885b044 --- /dev/null +++ b/deob/src/main/java/dev/openrs2/deob/analysis/DataFlowAnalyzer.kt @@ -0,0 +1,71 @@ +package dev.openrs2.deob.analysis + +import com.google.common.graph.Graph +import com.google.common.graph.Graphs +import org.objectweb.asm.tree.AbstractInsnNode +import org.objectweb.asm.tree.MethodNode + +abstract class DataFlowAnalyzer(owner: String, private val method: MethodNode, backwards: Boolean = false) { + private val graph: Graph + private val inSets = mutableMapOf() + private val outSets = mutableMapOf() + + init { + val forwardsGraph = ControlFlowAnalyzer().createGraph(owner, method) + graph = if (backwards) { + Graphs.transpose(forwardsGraph) + } else { + forwardsGraph + } + } + + protected abstract fun createInitialSet(): T + protected abstract fun join(set1: T, set2: T): T + protected abstract fun transfer(set: T, insn: AbstractInsnNode): T + + fun getInSet(insn: AbstractInsnNode): T? { + return getInSet(method.instructions.indexOf(insn)) + } + + fun getInSet(index: Int): T? { + return inSets[index] + } + + fun getOutSet(insn: AbstractInsnNode): T? { + return getOutSet(method.instructions.indexOf(insn)) + } + + fun getOutSet(index: Int): T? { + return outSets[index] + } + + fun analyze() { + for (node in graph.nodes()) { + outSets[node] = createInitialSet() + } + + var changed: Boolean + do { + changed = false + + for (node in graph.nodes()) { + val predecessors = graph.predecessors(node).map { pred -> outSets[pred]!! } + + val inSet = if (predecessors.isEmpty()) { + createInitialSet() + } else { + predecessors.reduce(this::join) + } + + inSets[node] = inSet + + val outSet = transfer(inSet, method.instructions[node]) + + if (outSets[node] != outSet) { + outSets[node] = outSet + changed = true + } + } + } while (changed) + } +}