From 7065b1b3ba2e95e73608706f44800da07975668e Mon Sep 17 00:00:00 2001
From: Skylot <skylot@gmail.com>
Date: Mon, 29 Mar 2021 20:35:40 +0100
Subject: [PATCH] fix: remove method with more than 255 args (#1026)

---
 jadx-core/src/main/java/jadx/core/Jadx.java   |  2 +
 .../java/jadx/core/dex/nodes/MethodNode.java  |  5 ++
 .../jadx/core/dex/visitors/CheckCode.java     | 48 +++++++++++++++++++
 3 files changed, 55 insertions(+)
 create mode 100644 jadx-core/src/main/java/jadx/core/dex/visitors/CheckCode.java

diff --git a/jadx-core/src/main/java/jadx/core/Jadx.java b/jadx-core/src/main/java/jadx/core/Jadx.java
index 9b26b806..516e818d 100644
--- a/jadx-core/src/main/java/jadx/core/Jadx.java
+++ b/jadx-core/src/main/java/jadx/core/Jadx.java
@@ -14,6 +14,7 @@ import jadx.api.JadxArgs;
 import jadx.core.dex.visitors.AttachCommentsVisitor;
 import jadx.core.dex.visitors.AttachMethodDetails;
 import jadx.core.dex.visitors.AttachTryCatchVisitor;
+import jadx.core.dex.visitors.CheckCode;
 import jadx.core.dex.visitors.ClassModifier;
 import jadx.core.dex.visitors.ConstInlineVisitor;
 import jadx.core.dex.visitors.ConstructorVisitor;
@@ -96,6 +97,7 @@ public class Jadx {
 		}
 
 		List<IDexTreeVisitor> passes = new ArrayList<>();
+		passes.add(new CheckCode());
 		if (args.isDebugInfo()) {
 			passes.add(new DebugInfoAttachVisitor());
 		}
diff --git a/jadx-core/src/main/java/jadx/core/dex/nodes/MethodNode.java b/jadx-core/src/main/java/jadx/core/dex/nodes/MethodNode.java
index 01a20a51..ab7696d7 100644
--- a/jadx-core/src/main/java/jadx/core/dex/nodes/MethodNode.java
+++ b/jadx-core/src/main/java/jadx/core/dex/nodes/MethodNode.java
@@ -612,6 +612,11 @@ public class MethodNode extends NotificationAttrNode implements IMethodDetails,
 		return noCode ? null : codeReader.getDebugInfo();
 	}
 
+	public void ignoreMethod() {
+		add(AFlag.DONT_GENERATE);
+		noCode = true;
+	}
+
 	/**
 	 * Calculate instructions count at currect stage
 	 */
diff --git a/jadx-core/src/main/java/jadx/core/dex/visitors/CheckCode.java b/jadx-core/src/main/java/jadx/core/dex/visitors/CheckCode.java
new file mode 100644
index 00000000..3691e68c
--- /dev/null
+++ b/jadx-core/src/main/java/jadx/core/dex/visitors/CheckCode.java
@@ -0,0 +1,48 @@
+package jadx.core.dex.visitors;
+
+import jadx.core.dex.info.MethodInfo;
+import jadx.core.dex.instructions.InsnType;
+import jadx.core.dex.nodes.InsnNode;
+import jadx.core.dex.nodes.MethodNode;
+import jadx.core.utils.exceptions.JadxException;
+
+@JadxVisitor(
+		name = "CheckCode",
+		desc = "Check and remove bad or incorrect code"
+)
+public class CheckCode extends AbstractVisitor {
+
+	@Override
+	public void visit(MethodNode mth) throws JadxException {
+		MethodInfo mthInfo = mth.getMethodInfo();
+		if (mthInfo.getArgumentsTypes().size() > 255) {
+			// java spec don't allow more than 255 args
+			if (canRemoveMethod(mth)) {
+				mth.ignoreMethod();
+			} else {
+				// TODO: convert args to array
+			}
+		}
+	}
+
+	private boolean canRemoveMethod(MethodNode mth) {
+		if (mth.getUseIn().isEmpty()) {
+			return true;
+		}
+		InsnNode[] insns = mth.getInstructions();
+		if (insns.length == 0) {
+			return true;
+		}
+		for (InsnNode insn : insns) {
+			if (insn != null && insn.getType() != InsnType.NOP) {
+				if (insn.getType() == InsnType.RETURN && insn.getArgsCount() == 0) {
+					// ignore void return
+				} else {
+					// found useful instruction
+					return false;
+				}
+			}
+		}
+		return true;
+	}
+}
-- 
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