Remove static calculations

SplotyCode · SplotyCode · commit 5acfda6fe8d4 · 2020-03-20T16:40:40.000+01:00
diff --git a/src/main/java/io/github/splotycode/deobfuscator/module/StaticCalculation.java b/src/main/java/io/github/splotycode/deobfuscator/module/StaticCalculation.java
@@ -0,0 +1,56 @@
+package io.github.splotycode.deobfuscator.module;
+
+import io.github.splotycode.deobfuscator.search.InstructionSearch;
+import io.github.splotycode.deobfuscator.util.InstructionUtil;
+import jdk.internal.org.objectweb.asm.Opcodes;
+import jdk.internal.org.objectweb.asm.tree.AbstractInsnNode;
+import jdk.internal.org.objectweb.asm.tree.ClassNode;
+import jdk.internal.org.objectweb.asm.tree.InsnNode;
+import jdk.internal.org.objectweb.asm.tree.MethodNode;
+
+public class StaticCalculation extends Module implements InstructionSearch {
+
+    @Override
+    public boolean transform(ClassNode classNode) {
+        return search(classNode);
+    }
+
+    @Override
+    public boolean onInstruction(MethodNode caller, AbstractInsnNode instruction) {
+        if (instruction instanceof InsnNode) {
+            if (instruction.getOpcode() == Opcodes.INEG) {
+                Integer negate = InstructionUtil.readInt(instruction.getPrevious());
+                if (negate != null) {
+                    caller.instructions.remove(instruction.getPrevious());
+                    caller.instructions.set(instruction, InstructionUtil.getStoreIntInstruction(-negate));
+                    return true;
+                }
+                return false;
+            }
+            AbstractInsnNode rightNode = instruction.getPrevious();
+            Integer right = InstructionUtil.readInt(rightNode);
+            if (right != null) {
+                AbstractInsnNode leftNode = rightNode.getPrevious();
+                Integer left = InstructionUtil.readInt(leftNode);
+                if (left != null) {
+                    int result;
+                    switch (instruction.getOpcode()) {
+                        case Opcodes.IXOR:
+                            result = left ^ right;
+                            break;
+                        case Opcodes.IAND:
+                            result = left & right;
+                            break;
+                        default:
+                            return false;
+                    }
+                    caller.instructions.set(instruction, InstructionUtil.getStoreIntInstruction(result));
+                    caller.instructions.remove(leftNode);
+                    caller.instructions.remove(rightNode);
+                    return true;
+                }
+            }
+        }
+        return false;
+    }
+}
