From 22c56761f3d4b02e9a5c39cb17599bf6faa32a97 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jindra=20Pet=C5=99=C3=ADk?= <jindra.petrik@gmail.com>
Date: Fri, 6 Oct 2023 10:08:44 +0200
Subject: [PATCH] Fixed #2094 AS3 Getting register names from debug info - do
 not allow assigning `_locX_` name to other register than X

---
 CHANGELOG.md                                     |  1 +
 .../decompiler/flash/abc/avm2/AVM2Code.java      | 16 ++++++++++++++--
 .../decompiler/flash/abc/types/MethodBody.java   |  2 +-
 .../decompiler/flash/abc/types/MethodInfo.java   |  2 +-
 4 files changed, 17 insertions(+), 4 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index e85368551..a4472e3dd 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -13,6 +13,7 @@ All notable changes to this project will be documented in this file.
 - [#2094] AS3 do not show body trait variables as FQN
 - [#2094] AS3 Missing use namespace
 - [#2094] AS3 missing star type on var and const
+- [#2094] AS3 Getting register names from debug info - do not allow assigning `_locX_` name to other register than X
 
 ## [19.0.0] - 2023-10-01
 ### Added
diff --git a/libsrc/ffdec_lib/src/com/jpexs/decompiler/flash/abc/avm2/AVM2Code.java b/libsrc/ffdec_lib/src/com/jpexs/decompiler/flash/abc/avm2/AVM2Code.java
index c3b24cf6c..8b491e6fc 100644
--- a/libsrc/ffdec_lib/src/com/jpexs/decompiler/flash/abc/avm2/AVM2Code.java
+++ b/libsrc/ffdec_lib/src/com/jpexs/decompiler/flash/abc/avm2/AVM2Code.java
@@ -1434,15 +1434,27 @@ public class AVM2Code implements Cloneable {
 
     private int toSourceCount = 0;
 
-    public Map<Integer, String> getLocalRegNamesFromDebug(ABC abc) {
+    public Map<Integer, String> getLocalRegNamesFromDebug(ABC abc, int maxRegs) {
         Map<Integer, String> regIndexToName = new HashMap<>();
         Map<String, Integer> regNameToIndex = new HashMap<>();
+        
+        Set<String> reservedRegNames = new HashSet<>();
+        for (int i = 0; i < maxRegs; i++) {
+            reservedRegNames.add(String.format(Configuration.registerNameFormat.get(), i));
+        }
 
         for (AVM2Instruction ins : code) {
             if (ins.definition instanceof DebugIns) {
                 if (ins.operands[0] == 1) {
                     String v = abc.constants.getString(ins.operands[1]);
-                    int regIndex = ins.operands[2] + 1;
+                    
+                    if (reservedRegNames.contains(v)) {
+                        //do not allow reassigning reserved _loc%d_ format to other local regs
+                        continue;
+                    }
+                    
+                    int regIndex = ins.operands[2] + 1;                    
+                    
                     // Same name already exists, it may be wrong names inserted by obfuscator
                     if (regNameToIndex.containsKey(v)) {
                         int existingIndex = regNameToIndex.get(v);
diff --git a/libsrc/ffdec_lib/src/com/jpexs/decompiler/flash/abc/types/MethodBody.java b/libsrc/ffdec_lib/src/com/jpexs/decompiler/flash/abc/types/MethodBody.java
index 370bdfd1c..acb2af745 100644
--- a/libsrc/ffdec_lib/src/com/jpexs/decompiler/flash/abc/types/MethodBody.java
+++ b/libsrc/ffdec_lib/src/com/jpexs/decompiler/flash/abc/types/MethodBody.java
@@ -277,7 +277,7 @@ public final class MethodBody implements Cloneable {
         }
 
         if (Configuration.getLocalNamesFromDebugInfo.get()) {
-            Map<Integer, String> debugRegNames = getCode().getLocalRegNamesFromDebug(abc);
+            Map<Integer, String> debugRegNames = getCode().getLocalRegNamesFromDebug(abc, max_regs);
             for (int k : debugRegNames.keySet()) {
                 ret.put(k, debugRegNames.get(k));
             }
diff --git a/libsrc/ffdec_lib/src/com/jpexs/decompiler/flash/abc/types/MethodInfo.java b/libsrc/ffdec_lib/src/com/jpexs/decompiler/flash/abc/types/MethodInfo.java
index 4e848bc25..a1677b6bf 100644
--- a/libsrc/ffdec_lib/src/com/jpexs/decompiler/flash/abc/types/MethodInfo.java
+++ b/libsrc/ffdec_lib/src/com/jpexs/decompiler/flash/abc/types/MethodInfo.java
@@ -310,7 +310,7 @@ public class MethodInfo {
     public GraphTextWriter getParamStr(GraphTextWriter writer, AVM2ConstantPool constants, MethodBody body, ABC abc, List<DottedChain> fullyQualifiedNames) {
         Map<Integer, String> localRegNames = new HashMap<>();
         if (body != null && Configuration.getLocalNamesFromDebugInfo.get()) {
-            localRegNames = body.getCode().getLocalRegNamesFromDebug(abc);
+            localRegNames = body.getCode().getLocalRegNamesFromDebug(abc, body.max_regs);
         }
 
         for (int i = 0; i < param_types.length; i++) {