avoid throwing EmptyStackExceptions in as2 deobfuscation

ffdec-findbugs-config.fbp

@@ -0,0 +1,9 @@
+<Project projectName="JPEXS">
+  <Jar>.\dist\ffdec.jar</Jar>
+  <AuxClasspathEntry>.\dist\lib</AuxClasspathEntry>
+  <SrcDir>.\src</SrcDir>
+  <SrcDir>.\libsrc</SrcDir>
+  <SuppressionFilter>
+    <LastVersion value="-1" relOp="NEQ"/>
+  </SuppressionFilter>
+</Project>

libsrc/ffdec_lib/src/com/jpexs/decompiler/flash/abc/avm2/deobfuscation/AVM2DeobfuscatorRegisters.java

@@ -175,6 +175,7 @@ private int visitCode(Reference<AVM2Instruction> assignment, Set<Integer> visite
         toVisit.add(idx);
         List<TranslateStack> toVisitStacks = new ArrayList<>();
         toVisitStacks.add(stack);
+        outer:
         while (!toVisit.isEmpty()) {
             idx = toVisit.remove(0);
             stack = toVisitStacks.remove(0);
@@ -192,6 +193,12 @@ private int visitCode(Reference<AVM2Instruction> assignment, Set<Integer> visite
                     InstructionDefinition def = ins.definition;
                     //System.err.println("" + idx + ": " + ins + " stack:" + stack.size());
 
+                    // do not throw EmptyStackException, much faster
+                    int requiredStackSize = ins.getStackPopCount(localData);
+                    if (stack.size() < requiredStackSize) {
+                        continue outer;
+                    }
+
                     ins.translate(localData, stack, output, Graph.SOP_USE_STATIC, "");
 
                     //if (!(def instanceof KillIns))

libsrc/ffdec_lib/src/com/jpexs/decompiler/flash/abc/avm2/instructions/AVM2Instruction.java

@@ -331,19 +331,39 @@ public String toStringNoAddress(AVM2ConstantPool constants, List<DottedChain> fu
     @Override
     public void translate(BaseLocalData localData, TranslateStack stack, List<GraphTargetItem> output, int staticOperation, String path) throws InterruptedException {
         AVM2LocalData aLocalData = (AVM2LocalData) localData;
+        //int expectedSize = stack.size() - getStackPopCount(localData, stack) + getStackPushCount(localData, stack);
         definition.translate(aLocalData.isStatic,
                 aLocalData.scriptIndex,
                 aLocalData.classIndex,
                 aLocalData.localRegs,
                 stack,
                 aLocalData.scopeStack,
                 aLocalData.constants, this, aLocalData.methodInfo, output, aLocalData.methodBody, aLocalData.abc, aLocalData.localRegNames, aLocalData.fullyQualifiedNames, null, aLocalData.localRegAssignmentIps, aLocalData.ip, aLocalData.refs, aLocalData.code);
+        /*if (stack.size() != expectedSize) {
+         throw new Error("HONFIKA stack size mismatch");
+         }*/
+    }
+
+    @Override
+    public int getStackPopCount(BaseLocalData localData, TranslateStack stack) {
+        AVM2LocalData aLocalData = (AVM2LocalData) localData;
+        return getStackPopCount(aLocalData);
+    }
+
+    @Override
+    public int getStackPushCount(BaseLocalData localData, TranslateStack stack) {
+        AVM2LocalData aLocalData = (AVM2LocalData) localData;
+        return getStackPushCount(aLocalData);
     }
 
     public int getStackPopCount(AVM2LocalData aLocalData) {
         return definition.getStackPopCount(this, aLocalData.abc);
     }
 
+    public int getStackPushCount(AVM2LocalData aLocalData) {
+        return definition.getStackPushCount(this, aLocalData.abc);
+    }
+
     @Override
     public boolean isJump() {
         return (definition instanceof JumpIns) || (fixedBranch > -1);

libsrc/ffdec_lib/src/com/jpexs/decompiler/flash/action/Action.java

@@ -711,6 +711,16 @@ public String getASMSource(ActionList container, Set<Long> knownAddreses, Script
     public void translate(TranslateStack stack, List<GraphTargetItem> output, HashMap<Integer, String> regNames, HashMap<String, GraphTargetItem> variables, HashMap<String, GraphTargetItem> functions, int staticOperation, String path) throws InterruptedException {
     }
 
+    @Override
+    public int getStackPopCount(BaseLocalData localData, TranslateStack stack) {
+        return 0;
+    }
+
+    @Override
+    public int getStackPushCount(BaseLocalData localData, TranslateStack stack) {
+        return 0;
+    }
+
     /**
      * Pops long value off the stack
      *
@@ -870,7 +880,16 @@ public static List<GraphTargetItem> actionsToTree(HashMap<Integer, String> regNa
     @Override
     public void translate(BaseLocalData localData, TranslateStack stack, List<GraphTargetItem> output, int staticOperation, String path) throws InterruptedException {
         ActionLocalData aLocalData = (ActionLocalData) localData;
+        /*int expectedSize = stack.size() - getStackPopCount(localData, stack);
+         if (expectedSize < 0) {
+         expectedSize = 0;
+         }
+         expectedSize += getStackPushCount(localData, stack);*/
+
         translate(stack, output, aLocalData.regNames, aLocalData.variables, aLocalData.functions, staticOperation, path);
+        /*if (stack.size() != expectedSize && !(this instanceof ActionPushDuplicate)) {
+         throw new Error("HONFIKA stack size mismatch");
+         }*/
     }
 
     @Override

libsrc/ffdec_lib/src/com/jpexs/decompiler/flash/action/deobfuscation/ActionDeobfuscator.java

@@ -257,20 +257,30 @@ private void executeActions(ActionList actions, int idx, int endIdx, ActionConst
                 }
 
                 if (action instanceof ActionDefineLocal) {
-                    GraphTargetItem top = stack.pop();
-                    String variableName = stack.peek().getResult().toString();
+                    if (stack.size() < 2) {
+                        return;
+                    }
+
+                    String variableName = stack.peek(2).getResult().toString();
                     result.defines.add(variableName);
-                    stack.push(top);
                 }
 
                 if (action instanceof ActionGetVariable) {
+                    if (stack.isEmpty()) {
+                        return;
+                    }
+
                     String variableName = stack.peek().getResult().toString();
                     if (!localData.variables.containsKey(variableName)) {
                         break;
                     }
                 }
 
                 if (action instanceof ActionCallFunction) {
+                    if (stack.isEmpty()) {
+                        return;
+                    }
+
                     String functionName = stack.pop().getResult().toString();
                     long numArgs = EcmaScript.toUint32(stack.pop().getResult());
                     if (numArgs == 0) {
@@ -283,6 +293,12 @@ private void executeActions(ActionList actions, int idx, int endIdx, ActionConst
                         break;
                     }
                 } else {
+                    // do not throw EmptyStackException, much faster
+                    int requiredStackSize = action.getStackPopCount(localData, stack);
+                    if (stack.size() < requiredStackSize) {
+                        return;
+                    }
+
                     action.translate(localData, stack, output, Graph.SOP_USE_STATIC, "");
                 }
 
@@ -348,6 +364,10 @@ private void executeActions(ActionList actions, int idx, int endIdx, ActionConst
 
                 if (action instanceof ActionIf) {
                     ActionIf aif = (ActionIf) action;
+                    if (stack.isEmpty()) {
+                        return;
+                    }
+
                     if (EcmaScript.toBoolean(stack.pop().getResult())) {
                         long address = aif.getAddress() + aif.getTotalActionLength() + aif.getJumpOffset();
                         idx = actions.indexOf(actions.getByAddress(address));

libsrc/ffdec_lib/src/com/jpexs/decompiler/flash/action/deobfuscation/ActionDeobfuscatorSimple.java

@@ -291,6 +291,12 @@ private void executeActions(ActionList actions, int idx, int endIdx, ExecutionRe
                  System.out.print(" '" + stack.get(j).getResult() + "'");
                  }
                  System.out.println();*/
+                // do not throw EmptyStackException, much faster
+                int requiredStackSize = action.getStackPopCount(localData, stack);
+                if (stack.size() < requiredStackSize) {
+                    return;
+                }
+
                 action.translate(localData, stack, output, Graph.SOP_USE_STATIC, "");
 
                 if (!(action instanceof ActionPush
@@ -341,6 +347,10 @@ private void executeActions(ActionList actions, int idx, int endIdx, ExecutionRe
 
                 if (action instanceof ActionIf) {
                     ActionIf aif = (ActionIf) action;
+                    if (stack.isEmpty()) {
+                        return;
+                    }
+
                     if (EcmaScript.toBoolean(stack.pop().getResult())) {
                         long address = aif.getAddress() + aif.getTotalActionLength() + aif.getJumpOffset();
                         idx = actions.indexOf(actions.getByAddress(address));

libsrc/ffdec_lib/src/com/jpexs/decompiler/flash/action/flashlite/ActionFSCommand2.java

@@ -1,20 +1,22 @@
 /*
  *  Copyright (C) 2010-2015 JPEXS, All rights reserved.
- * 
+ *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
  * License as published by the Free Software Foundation; either
  * version 3.0 of the License, or (at your option) any later version.
- * 
+ *
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Lesser General Public License for more details.
- * 
+ *
  * You should have received a copy of the GNU Lesser General Public
- * License along with this library. */
+ * License along with this library.
+ */
 package com.jpexs.decompiler.flash.action.flashlite;
 
+import com.jpexs.decompiler.flash.BaseLocalData;
 import com.jpexs.decompiler.flash.action.Action;
 import com.jpexs.decompiler.flash.action.model.FSCommand2ActionItem;
 import com.jpexs.decompiler.graph.GraphTargetItem;
@@ -44,4 +46,19 @@ public void translate(TranslateStack stack, List<GraphTargetItem> output, HashMa
         }
         stack.push(new FSCommand2ActionItem(this, command, args));
     }
+
+    @Override
+    public int getStackPopCount(BaseLocalData localData, TranslateStack stack) {
+        int result = 2;
+        if (!stack.isEmpty()) {
+            result += stack.peek().getAsLong();
+        }
+
+        return result;
+    }
+
+    @Override
+    public int getStackPushCount(BaseLocalData localData, TranslateStack stack) {
+        return 1;
+    }
 }

libsrc/ffdec_lib/src/com/jpexs/decompiler/flash/action/special/ActionDeobfuscatePop.java

@@ -1,18 +1,19 @@
 /*
  *  Copyright (C) 2010-2015 JPEXS, All rights reserved.
- * 
+ *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
  * License as published by the Free Software Foundation; either
  * version 3.0 of the License, or (at your option) any later version.
- * 
+ *
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Lesser General Public License for more details.
- * 
+ *
  * You should have received a copy of the GNU Lesser General Public
- * License along with this library. */
+ * License along with this library.
+ */
 package com.jpexs.decompiler.flash.action.special;
 
 import com.jpexs.decompiler.flash.BaseLocalData;
@@ -40,7 +41,8 @@ public void translate(BaseLocalData localData, TranslateStack stack, List<GraphT
         if (stack.isEmpty()) {
             return;
         }
-        GraphTargetItem val = stack.pop();
+
+        stack.pop(); //Just ignore the value
     }
 
     @Override

libsrc/ffdec_lib/src/com/jpexs/decompiler/flash/action/swf4/ActionAdd.java

@@ -1,20 +1,22 @@
 /*
  *  Copyright (C) 2010-2015 JPEXS, All rights reserved.
- * 
+ *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
  * License as published by the Free Software Foundation; either
  * version 3.0 of the License, or (at your option) any later version.
- * 
+ *
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Lesser General Public License for more details.
- * 
+ *
  * You should have received a copy of the GNU Lesser General Public
- * License along with this library. */
+ * License along with this library.
+ */
 package com.jpexs.decompiler.flash.action.swf4;
 
+import com.jpexs.decompiler.flash.BaseLocalData;
 import com.jpexs.decompiler.flash.action.Action;
 import com.jpexs.decompiler.flash.action.model.operations.AddActionItem;
 import com.jpexs.decompiler.graph.GraphTargetItem;
@@ -39,4 +41,14 @@ public void translate(TranslateStack stack, List<GraphTargetItem> output, HashMa
         GraphTargetItem b = stack.pop();
         stack.push(new AddActionItem(this, b, a, false));
     }
+
+    @Override
+    public int getStackPopCount(BaseLocalData localData, TranslateStack stack) {
+        return 2;
+    }
+
+    @Override
+    public int getStackPushCount(BaseLocalData localData, TranslateStack stack) {
+        return 1;
+    }
 }

libsrc/ffdec_lib/src/com/jpexs/decompiler/flash/action/swf4/ActionAnd.java

@@ -1,20 +1,22 @@
 /*
  *  Copyright (C) 2010-2015 JPEXS, All rights reserved.
- * 
+ *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
  * License as published by the Free Software Foundation; either
  * version 3.0 of the License, or (at your option) any later version.
- * 
+ *
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Lesser General Public License for more details.
- * 
+ *
  * You should have received a copy of the GNU Lesser General Public
- * License along with this library. */
+ * License along with this library.
+ */
 package com.jpexs.decompiler.flash.action.swf4;
 
+import com.jpexs.decompiler.flash.BaseLocalData;
 import com.jpexs.decompiler.flash.action.Action;
 import com.jpexs.decompiler.flash.action.model.operations.AndActionItem;
 import com.jpexs.decompiler.graph.GraphTargetItem;
@@ -39,4 +41,14 @@ public void translate(TranslateStack stack, List<GraphTargetItem> output, HashMa
         GraphTargetItem b = stack.pop();
         stack.push(new AndActionItem(this, b, a));
     }
+
+    @Override
+    public int getStackPopCount(BaseLocalData localData, TranslateStack stack) {
+        return 2;
+    }
+
+    @Override
+    public int getStackPushCount(BaseLocalData localData, TranslateStack stack) {
+        return 1;
+    }
 }

libsrc/ffdec_lib/src/com/jpexs/decompiler/flash/action/swf4/ActionAsciiToChar.java

@@ -1,20 +1,22 @@
 /*
  *  Copyright (C) 2010-2015 JPEXS, All rights reserved.
- * 
+ *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
  * License as published by the Free Software Foundation; either
  * version 3.0 of the License, or (at your option) any later version.
- * 
+ *
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Lesser General Public License for more details.
- * 
+ *
  * You should have received a copy of the GNU Lesser General Public
- * License along with this library. */
+ * License along with this library.
+ */
 package com.jpexs.decompiler.flash.action.swf4;
 
+import com.jpexs.decompiler.flash.BaseLocalData;
 import com.jpexs.decompiler.flash.action.Action;
 import com.jpexs.decompiler.flash.action.model.AsciiToCharActionItem;
 import com.jpexs.decompiler.graph.GraphTargetItem;
@@ -38,4 +40,14 @@ public void translate(TranslateStack stack, List<GraphTargetItem> output, HashMa
         GraphTargetItem a = stack.pop();
         stack.push(new AsciiToCharActionItem(this, a));
     }
+
+    @Override
+    public int getStackPopCount(BaseLocalData localData, TranslateStack stack) {
+        return 1;
+    }
+
+    @Override
+    public int getStackPushCount(BaseLocalData localData, TranslateStack stack) {
+        return 1;
+    }
 }