Merge pull request #85 from EpicPlayerA10/fix/fix-npe-on-optional-of

Fix NPE on Optional.of

deobfuscator-api/src/main/java/org/objectweb/asm/tree/AbstractInsnNode.java

@@ -34,6 +34,8 @@
 import java.util.Map;
 import java.util.function.Consumer;
 import java.util.function.Predicate;
+
+import org.jetbrains.annotations.Nullable;
 import org.objectweb.asm.MethodVisitor;
 import org.objectweb.asm.Type;
 import uwu.narumi.deobfuscator.api.asm.matcher.rule.Match;
@@ -344,6 +346,7 @@ public Type asType() {
     return (Type) ((LdcInsnNode) this).cst;
   }
 
+  @Nullable
   public Object asConstant() {
     if (isNumber()) {
       return asNumber();

deobfuscator-api/src/main/java/org/objectweb/asm/tree/analysis/OriginalSourceInterpreter.java

@@ -135,11 +135,11 @@ public OriginalSourceValue unaryOperation(final AbstractInsnNode insn, final Ori
 
     // Narumii start - Predict constant
     if (AsmMathHelper.isMathUnaryOperation(insn.getOpcode())) {
-      Optional<Object> constant = value.getConstantValue();
+      OriginalSourceValue.ConstantValue constant = value.getConstantValue();
 
-      if (constant.isPresent() && constant.get() instanceof Number constNum) {
+      if (constant != null && constant.get() instanceof Number constNum) {
         Number result = AsmMathHelper.mathUnaryOperation(constNum, insn.getOpcode());
-        return new OriginalSourceValue(size, insn, Optional.of(result));
+        return new OriginalSourceValue(size, insn, OriginalSourceValue.ConstantValue.of(result));
       }
     }
     // Narumii end
@@ -179,12 +179,12 @@ public OriginalSourceValue binaryOperation(
 
     // Narumii start - Predict constant
     if (AsmMathHelper.isMathBinaryOperation(insn.getOpcode())) {
-      Optional<Object> constant1 = value1.getConstantValue();
-      Optional<Object> constant2 = value2.getConstantValue();
+      OriginalSourceValue.ConstantValue constant1 = value1.getConstantValue();
+      OriginalSourceValue.ConstantValue constant2 = value2.getConstantValue();
 
-      if (constant1.isPresent() && constant2.isPresent() && constant1.get() instanceof Number constNum1 && constant2.get() instanceof Number constNum2) {
+      if (constant1 != null && constant2 != null && constant1.get() instanceof Number constNum1 && constant2.get() instanceof Number constNum2) {
         Number result = AsmMathHelper.mathBinaryOperation(constNum1, constNum2, insn.getOpcode());
-        return new OriginalSourceValue(size, insn, Optional.of(result));
+        return new OriginalSourceValue(size, insn, OriginalSourceValue.ConstantValue.of(result));
       }
     }
     // Narumii end
@@ -228,9 +228,7 @@ public OriginalSourceValue merge(final OriginalSourceValue value1, final Origina
       Set<AbstractInsnNode> setUnion =
           ((SmallSet<AbstractInsnNode>) value1.insns)
               .union((SmallSet<AbstractInsnNode>) value2.insns);
-      // Narumii start
-      if (setUnion == value1.insns && value1.size == value2.size && Objects.equals(value1.copiedFrom, value2.copiedFrom)) {
-      // Narumii end
+      if (setUnion == value1.insns && value1.size == value2.size && Objects.equals(value1.copiedFrom, value2.copiedFrom)) { // Narumii
         return value1;
       } else {
         // Narumii start
@@ -242,9 +240,7 @@ public OriginalSourceValue merge(final OriginalSourceValue value1, final Origina
         // Narumii end
       }
     }
-    // Narumii start
-    if (value1.size != value2.size || !containsAll(value1.insns, value2.insns) || !Objects.equals(value1.copiedFrom, value2.copiedFrom)) {
-    // Narumii end
+    if (value1.size != value2.size || !containsAll(value1.insns, value2.insns) || !Objects.equals(value1.copiedFrom, value2.copiedFrom)) { // Narumii
       HashSet<AbstractInsnNode> setUnion = new HashSet<>();
       setUnion.addAll(value1.insns);
       setUnion.addAll(value2.insns);

deobfuscator-api/src/main/java/org/objectweb/asm/tree/analysis/OriginalSourceValue.java

@@ -44,35 +44,42 @@ public class OriginalSourceValue extends SourceValue {
    * 8: C:
    * 9:   ...
    * </pre>
+   *
    * When the current class is source value of instruction at line 6, then it will follow all
    * instructions (DUP, ILOAD) and jumps to get the original source value of this instruction at line 6.
    * In this example, it will return source value of instruction at line 2.
    */
   public final OriginalSourceValue originalSource;
 
   /**
-   * Predicted constant value. It holds a constant value such as {@link Integer}, {@link Double},
-   * {@link Float}, {@link String}, {@link Type} and {@code null}. It also follows all math operations
-   * and jumps to get the constant value.
+   * Predicted constant value that holds an object to constant value such as {@link Integer}, {@link Double},
+   * {@link Float}, {@link String}, {@link Type} and {@code null}. Additionally, to {@link #originalSource} it is
+   * also doing all math operations on math operation instructions.
    *
    * <p>
    * Consider this example:
    * <pre>
    * 1: A:
    * 2:   ldc 12L
-   * 3:   ldiv
-   * 4:   l2i
-   * 5:   lookupswitch {
-   * 6:     ...
-   * 7:   }
+   * 3:   ldc 2L
+   * 4:   ldiv
+   * 5:   l2i
+   * 6:   lookupswitch {
+   * 7:     ...
+   * 8:   }
    * </pre>
    *
-   * In line 2, the constant value is 12L. In line 3, the constant value is 12L / 2L = 6L. In line 4,
-   * the constant value is 6 (but cast to integer).
-   * It is so convenient because for example if you want to get value of
-   * a IMUL instruction, then this field already contains the calculated value! No need to calculate it manually from stack values.
+   * In line 2, the constant value is 12L.<br>
+   * In line 3, the constant value is 2L.<br>
+   * In line 4, the constant value is 12L / 2L = 6L.<br>
+   * In line 5, the constant value is 6 (but cast to integer).
+   *
+   * <p>
+   * It is so convenient because for example if you want to get value of a IMUL instruction,
+   * then this field already contains the calculated value! No need to calculate it manually from stack values.
    */
-  private Optional<Object> constantValue = Optional.empty();
+  @Nullable
+  private ConstantValue constantValue = null;
 
   public OriginalSourceValue(int size) {
     this(size, Set.of());
@@ -91,10 +98,10 @@ public OriginalSourceValue(OriginalSourceValue copiedFrom, AbstractInsnNode insn
   }
 
   public OriginalSourceValue(int size, Set<AbstractInsnNode> insnSet, @Nullable OriginalSourceValue copiedFrom) {
-    this(size, insnSet, copiedFrom, Optional.empty());
+    this(size, insnSet, copiedFrom, null);
   }
 
-  public OriginalSourceValue(int size, AbstractInsnNode insnNode, Optional<Object> constantValue) {
+  public OriginalSourceValue(int size, AbstractInsnNode insnNode, @Nullable ConstantValue constantValue) {
     this(size, Set.of(insnNode), null, constantValue);
   }
 
@@ -107,11 +114,11 @@ public OriginalSourceValue(int size, AbstractInsnNode insnNode, Optional<Object>
    * @param copiedFrom The value from which this value was copied or null if it was not copied
    * @param constantValue Predicted constant value if exists
    */
-  public OriginalSourceValue(int size, Set<AbstractInsnNode> insnSet, @Nullable OriginalSourceValue copiedFrom, Optional<Object> constantValue) {
+  public OriginalSourceValue(int size, Set<AbstractInsnNode> insnSet, @Nullable OriginalSourceValue copiedFrom, @Nullable ConstantValue constantValue) {
     super(size, insnSet);
     this.copiedFrom = copiedFrom;
     this.originalSource = copiedFrom == null ? this : copiedFrom.originalSource;
-    if (constantValue.isPresent()) {
+    if (constantValue != null) {
       // If the constant value is present, then use it
       this.constantValue = constantValue;
     } else if (copiedFrom != null) {
@@ -121,7 +128,7 @@ public OriginalSourceValue(int size, Set<AbstractInsnNode> insnSet, @Nullable Or
       // Try to infer constant value from producer
       AbstractInsnNode insn = insnSet.iterator().next();
       if (insn.isConstant()) {
-        this.constantValue = Optional.of(insn.asConstant());
+        this.constantValue = ConstantValue.of(insn.asConstant());
       }
     }
   }
@@ -150,7 +157,8 @@ public AbstractInsnNode getProducer() {
   /**
    * See {@link #constantValue}.
    */
-  public Optional<Object> getConstantValue() {
+  @Nullable
+  public ConstantValue getConstantValue() {
     return constantValue;
   }
 
@@ -183,4 +191,21 @@ public boolean equals(Object o) {
   public int hashCode() {
     return Objects.hash(super.hashCode(), copiedFrom);
   }
+
+  /**
+   * We need to create our own {@link Optional}-like class because {@link Optional} can't
+   * store nullable values which we need to store.
+   *
+   * @param value A constant value. It can be {@link Integer}, {@link Double},
+   * {@link Float}, {@link String}, {@link Type} or {@code null}
+   */
+  public record ConstantValue(Object value) {
+    public static ConstantValue of(Object value) {
+      return new ConstantValue(value);
+    }
+
+    public Object get() {
+      return value;
+    }
+  }
 }

deobfuscator-api/src/main/java/uwu/narumi/deobfuscator/api/helper/AsmHelper.java

@@ -5,7 +5,7 @@
 import org.objectweb.asm.MethodVisitor;
 import org.objectweb.asm.Opcodes;
 import org.objectweb.asm.tree.*;
-import org.objectweb.asm.tree.analysis.Analyzer;
+import org.objectweb.asm.tree.analysis.AnalyzerException;
 import org.objectweb.asm.tree.analysis.Frame;
 import org.objectweb.asm.tree.analysis.JumpPredictingAnalyzer;
 import org.objectweb.asm.tree.analysis.OriginalSourceInterpreter;
@@ -142,17 +142,18 @@ public static List<AbstractInsnNode> getInstructionsBetween(
   public static Map<AbstractInsnNode, Frame<OriginalSourceValue>> analyzeSource(
       ClassNode classNode, MethodNode methodNode
   ) {
+    Map<AbstractInsnNode, Frame<OriginalSourceValue>> frames = new HashMap<>();
+    Frame<OriginalSourceValue>[] framesArray;
     try {
-      Map<AbstractInsnNode, Frame<OriginalSourceValue>> frames = new HashMap<>();
-      Frame<OriginalSourceValue>[] framesArray =
-          new JumpPredictingAnalyzer(new OriginalSourceInterpreter()).analyze(classNode.name, methodNode);
-      for (int i = 0; i < framesArray.length; i++) {
-        frames.put(methodNode.instructions.get(i), framesArray[i]);
-      }
-      return frames;
-    } catch (Exception e) {
+      framesArray = new JumpPredictingAnalyzer(new OriginalSourceInterpreter()).analyze(classNode.name, methodNode);
+    } catch (AnalyzerException e) {
+      // Return null on invalid method
       return null;
     }
+    for (int i = 0; i < framesArray.length; i++) {
+      frames.put(methodNode.instructions.get(i), framesArray[i]);
+    }
+    return frames;
   }
 
   /**

deobfuscator-api/src/main/java/uwu/narumi/deobfuscator/api/helper/AsmMathHelper.java

@@ -420,8 +420,8 @@ public static Optional<Boolean> predictIf(JumpInsnNode jumpInsn, Frame<OriginalS
 
       // Get instruction from stack that is passed to if statement
       OriginalSourceValue sourceValue = frame.getStack(frame.getStackSize() - 1);
-      Optional<Object> constantValue = sourceValue.getConstantValue();
-      if (constantValue.isEmpty()) return Optional.empty();
+      OriginalSourceValue.ConstantValue constantValue = sourceValue.getConstantValue();
+      if (constantValue == null) return Optional.empty();
 
       // Process if statement
       if (constantValue.get() instanceof Integer value) {
@@ -438,9 +438,9 @@ public static Optional<Boolean> predictIf(JumpInsnNode jumpInsn, Frame<OriginalS
       // Get instructions from stack that are passed to if statement
       OriginalSourceValue sourceValue1 = frame.getStack(frame.getStackSize() - 2);
       OriginalSourceValue sourceValue2 = frame.getStack(frame.getStackSize() - 1);
-      Optional<Object> constValue1 = sourceValue1.getConstantValue();
-      Optional<Object> constValue2 = sourceValue2.getConstantValue();
-      if (constValue1.isEmpty() || constValue2.isEmpty()) return Optional.empty();
+      OriginalSourceValue.ConstantValue constValue1 = sourceValue1.getConstantValue();
+      OriginalSourceValue.ConstantValue constValue2 = sourceValue2.getConstantValue();
+      if (constValue1 == null || constValue2 == null) return Optional.empty();
 
       // Process if statement
       if (constValue1.get() instanceof Integer value1 && constValue2.get() instanceof Integer value2) {
@@ -462,8 +462,8 @@ public static Optional<Boolean> predictIf(JumpInsnNode jumpInsn, Frame<OriginalS
    */
   public static Optional<LabelNode> predictLookupSwitch(LookupSwitchInsnNode lookupSwitchInsn, Frame<OriginalSourceValue> frame) {
     OriginalSourceValue sourceValue = frame.getStack(frame.getStackSize() - 1);
-    Optional<Object> constantValue = sourceValue.getConstantValue();
-    if (constantValue.isEmpty()) return Optional.empty();
+    OriginalSourceValue.ConstantValue constantValue = sourceValue.getConstantValue();
+    if (constantValue == null) return Optional.empty();
 
     if (constantValue.get() instanceof Integer value) {
       int index = lookupSwitchInsn.keys.indexOf(value);
@@ -486,8 +486,8 @@ public static Optional<LabelNode> predictLookupSwitch(LookupSwitchInsnNode looku
    */
   public static Optional<LabelNode> predictTableSwitch(TableSwitchInsnNode tableSwitchInsn, Frame<OriginalSourceValue> frame) {
     OriginalSourceValue sourceValue = frame.getStack(frame.getStackSize() - 1);
-    Optional<Object> constantValue = sourceValue.getConstantValue();
-    if (constantValue.isEmpty()) return Optional.empty();
+    OriginalSourceValue.ConstantValue constantValue = sourceValue.getConstantValue();
+    if (constantValue == null) return Optional.empty();
 
     if (constantValue.get() instanceof Integer value) {
       int index = value - tableSwitchInsn.min;