From 196f7cb153368bc855606665fc1e97d82c31e91e Mon Sep 17 00:00:00 2001
From: Julian Dolby <juliandolby@gmail.com>
Date: Thu, 31 May 2018 19:32:02 -0400
Subject: [PATCH] fix for nasty bug in decoding dup2_x2

---
 com.ibm.wala.shrike/src/com/ibm/wala/shrikeBT/Decoder.java | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/com.ibm.wala.shrike/src/com/ibm/wala/shrikeBT/Decoder.java b/com.ibm.wala.shrike/src/com/ibm/wala/shrikeBT/Decoder.java
index 01eea0472..427457b32 100644
--- a/com.ibm.wala.shrike/src/com/ibm/wala/shrikeBT/Decoder.java
+++ b/com.ibm.wala.shrike/src/com/ibm/wala/shrikeBT/Decoder.java
@@ -513,10 +513,11 @@ public abstract class Decoder implements Constants {
       case OP_dup2_x1:
         i = DupInstruction.make(elemCount(stackWords, stackLen - 1), 1);
         break;
-      case OP_dup2_x2:
-        i = DupInstruction.make(elemCount(stackWords, stackLen - 1), elemCount(stackWords, stackLen - 2));
+      case OP_dup2_x2: {
+        int twoDown = elemCount(stackWords, stackLen - 1);
+        i = DupInstruction.make(twoDown, elemCount(stackWords, stackLen - twoDown - 1));
         break;
-      case OP_iinc: {
+      } case OP_iinc: {
         int v = wide ? decodeUShort(index) : (code[index] & 0xFF);
         int c = wide ? decodeShort(index + 2) : code[index + 1];