From d2e757ee44c6425bd801b6f76ff14537203281b9 Mon Sep 17 00:00:00 2001
From: Søren Gjesse <sgjesse@google.com>
Date: Mon, 14 Dec 2020 14:52:31 +0100
Subject: Check for extended frame type when updating StackTableOffset offset

Fixes #350
---
 src/test/javassist/bytecode/StackMapTest.java | 77 +++++++++++++++++++++++++++
 1 file changed, 77 insertions(+)

(limited to 'src/test')

diff --git a/src/test/javassist/bytecode/StackMapTest.java b/src/test/javassist/bytecode/StackMapTest.java
index 7ea415a9..a0a4f1b1 100644
--- a/src/test/javassist/bytecode/StackMapTest.java
+++ b/src/test/javassist/bytecode/StackMapTest.java
@@ -923,4 +923,81 @@ public class StackMapTest extends TestCase {
         else
             ci.insert(newCode.get());
     }
+
+    public void testIssue350() throws Exception {
+        byte sameLocals1StackItemFrameExtended = 247 - 256;
+        byte sameFrameExtended = 251 - 256;
+        byte appendFrame = 252 - 256;
+        ConstPool cp = new ConstPool("Test");
+        StackMapTable stmt;
+        int originalLength;
+
+        stmt = new StackMapTable(cp, new byte[] {
+            0, 1,
+            sameLocals1StackItemFrameExtended, 0, 63, 1
+        });
+        originalLength = stmt.info.length;
+        assertEquals(63, stmt.info[4]);
+        stmt.shiftPc(0, 2, false);
+        assertEquals(originalLength, stmt.info.length);
+        assertEquals(65, stmt.info[4]);
+
+        stmt = new StackMapTable(cp, new byte[] {
+            0, 1,
+            sameFrameExtended, 0, 63
+        });
+        originalLength = stmt.info.length;
+        assertEquals(63, stmt.info[4]);
+        stmt.shiftPc(0, 2, false);
+        assertEquals(originalLength, stmt.info.length);
+        assertEquals(65, stmt.info[4]);
+
+        stmt = new StackMapTable(cp, new byte[] {
+            0, 2,
+            sameLocals1StackItemFrameExtended, 0, 63, 1,
+            sameFrameExtended, 0, 63
+        });
+        originalLength = stmt.info.length;
+        assertEquals(63, stmt.info[4]);
+        assertEquals(63, stmt.info[8]);
+        stmt.shiftPc(0, 2, false);
+        assertEquals(originalLength, stmt.info.length);
+        assertEquals(65, stmt.info[4]);
+        assertEquals(63, stmt.info[8]);
+        stmt.shiftPc(100, 2, false);
+        assertEquals(65, stmt.info[4]);
+        assertEquals(65, stmt.info[8]);
+
+        // Actual StackMapTable reported in https://github.com/jboss-javassist/javassist/issues/350.
+        stmt = new StackMapTable(cp, new byte[] {
+            0, 7, // size
+            sameLocals1StackItemFrameExtended, 0, 76, 7, 2, 206 - 256,
+            sameLocals1StackItemFrameExtended, 0, 63, 7, 2, 221 - 256,
+            appendFrame, 0, 63, 7, 0, 14,
+            appendFrame, 0, 43, 7, 2, 225 - 256, 1,
+            74, 7, 0, 19,  // same_locals_1_stack_item_frame (not extended)
+            appendFrame, 0, 23, 7, 0, 19,
+            66, 7, 2, 225 - 256 // same_locals_1_stack_item_frame (not extended)
+        });
+        assertEquals(63, stmt.info[10]);
+        originalLength = stmt.info.length;
+
+        stmt.shiftPc(100, 2, false);
+        assertEquals(originalLength, stmt.info.length);
+        assertEquals(65, stmt.info[10]);
+    }
+
+    public static void dump(byte[] content) {
+        final int bytesPerLine = 16;
+        for (int i = 0; i < content.length; i += bytesPerLine) {
+            for (int j = 0; j < bytesPerLine && i + j < content.length; j++) {
+                int unsignedByte = content[i + j];
+                if (unsignedByte < 0) {
+                    unsignedByte = 256 + unsignedByte;
+                }
+                System.out.print(unsignedByte + ", ");
+            }
+            System.out.println();
+        }
+    }
 }
-- 
cgit v1.2.3