From 861376352049ff17804549e69260b0ca74092816 Mon Sep 17 00:00:00 2001
From: Graham <gpe@openrs2.dev>
Date: Sun, 11 Aug 2019 14:03:07 +0100
Subject: [PATCH] Inline bitwise AND/OR/XOR methods

---
 .../java/dev/openrs2/deob/Deobfuscator.java   |  2 +
 .../deob/transform/BitwiseOpTransformer.java  | 97 +++++++++++++++++++
 2 files changed, 99 insertions(+)
 create mode 100644 deob/src/main/java/dev/openrs2/deob/transform/BitwiseOpTransformer.java

diff --git a/deob/src/main/java/dev/openrs2/deob/Deobfuscator.java b/deob/src/main/java/dev/openrs2/deob/Deobfuscator.java
index 8c878077d4..103b89ad17 100644
--- a/deob/src/main/java/dev/openrs2/deob/Deobfuscator.java
+++ b/deob/src/main/java/dev/openrs2/deob/Deobfuscator.java
@@ -12,6 +12,7 @@ import dev.openrs2.asm.transform.Transformer;
 import dev.openrs2.deob.remap.ClassNamePrefixer;
 import dev.openrs2.deob.remap.TypedRemapper;
 import dev.openrs2.deob.transform.BitShiftTransformer;
+import dev.openrs2.deob.transform.BitwiseOpTransformer;
 import dev.openrs2.deob.transform.CanvasTransformer;
 import dev.openrs2.deob.transform.ClassForNameTransformer;
 import dev.openrs2.deob.transform.CounterTransformer;
@@ -34,6 +35,7 @@ public final class Deobfuscator {
 		new CounterTransformer(),
 		new CanvasTransformer(),
 		new FieldOrderTransformer(),
+		new BitwiseOpTransformer(),
 		new DummyTransformer()
 	);
 
diff --git a/deob/src/main/java/dev/openrs2/deob/transform/BitwiseOpTransformer.java b/deob/src/main/java/dev/openrs2/deob/transform/BitwiseOpTransformer.java
new file mode 100644
index 0000000000..0738b1770b
--- /dev/null
+++ b/deob/src/main/java/dev/openrs2/deob/transform/BitwiseOpTransformer.java
@@ -0,0 +1,97 @@
+package dev.openrs2.deob.transform;
+
+import java.util.HashMap;
+import java.util.Map;
+
+import dev.openrs2.asm.InsnMatcher;
+import dev.openrs2.asm.MemberRef;
+import dev.openrs2.asm.classpath.ClassPath;
+import dev.openrs2.asm.transform.Transformer;
+import org.objectweb.asm.Opcodes;
+import org.objectweb.asm.tree.ClassNode;
+import org.objectweb.asm.tree.InsnNode;
+import org.objectweb.asm.tree.MethodInsnNode;
+import org.objectweb.asm.tree.MethodNode;
+import org.objectweb.asm.tree.VarInsnNode;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+public final class BitwiseOpTransformer extends Transformer {
+	private static final Logger logger = LoggerFactory.getLogger(BitwiseOpTransformer.class);
+
+	private static final InsnMatcher BITWISE_OP_MATCHER = InsnMatcher.compile("^ILOAD ILOAD (IXOR | IAND | IOR) IRETURN$");
+	private static final String BITWISE_OP_DESC = "(II)I";
+
+	private final Map<MemberRef, Integer> methodOps = new HashMap<>();
+	private int inlinedOps;
+
+	@Override
+	protected void preTransform(ClassPath classPath) {
+		methodOps.clear();
+		inlinedOps = 0;
+
+		for (var library : classPath.getLibraries()) {
+			for (var clazz : library) {
+				for (var method : clazz.methods) {
+					if ((method.access & (Opcodes.ACC_NATIVE | Opcodes.ACC_ABSTRACT)) != 0) {
+						continue;
+					}
+
+					if ((method.access & Opcodes.ACC_STATIC) == 0) {
+						continue;
+					}
+
+					if (!method.desc.equals(BITWISE_OP_DESC)) {
+						continue;
+					}
+
+					BITWISE_OP_MATCHER.match(method).findAny().ifPresent(match -> {
+						var iload0 = (VarInsnNode) match.get(0);
+						if (iload0.var != 0) {
+							return;
+						}
+
+						var iload1 = (VarInsnNode) match.get(1);
+						if (iload1.var != 1) {
+							return;
+						}
+
+						var methodRef = new MemberRef(clazz.name, method.name, method.desc);
+						methodOps.put(methodRef, match.get(2).getOpcode());
+					});
+				}
+			}
+		}
+	}
+
+	@Override
+	protected boolean transformClass(ClassNode clazz) {
+		clazz.methods.removeIf(m -> methodOps.containsKey(new MemberRef(clazz.name, m.name, m.desc)));
+		return false;
+	}
+
+	@Override
+	protected boolean transformCode(ClassNode clazz, MethodNode method) {
+		for (var it = method.instructions.iterator(); it.hasNext(); ) {
+			var insn = it.next();
+			if (insn.getOpcode() != Opcodes.INVOKESTATIC) {
+				continue;
+			}
+
+			var invokestatic = (MethodInsnNode) insn;
+			var methodRef = new MemberRef(invokestatic.owner, invokestatic.name, invokestatic.desc);
+			var opcode = methodOps.get(methodRef);
+			if (opcode != null) {
+				it.set(new InsnNode(opcode));
+				inlinedOps++;
+			}
+		}
+
+		return false;
+	}
+
+	@Override
+	protected void postTransform(ClassPath classPath) {
+		logger.info("Inlined {} bitwise ops and removed {} redundant methods", inlinedOps, methodOps.size());
+	}
+}