GP-5915 Fix bug in ConditionalJoin

Ghidra/Features/Decompiler/src/decompile/cpp/block.cc

@@ -638,6 +638,17 @@ JumpTable *FlowBlock::getJumptable(void) const
   return jt;
 }
 
+/// Print a single unique identifier for \b this block
+/// \param s is the output stream
+void FlowBlock::printShortHeader(ostream &s) const
+
+{
+  s << "Block_" << dec << index;
+  if (!getStart().isInvalid()) {
+    s << ':' << getStart();
+  }
+}
+
 /// Given a string describing a FlowBlock type, return the block_type.
 /// This is currently only used by the decode() process.
 /// TODO: Fill in the remaining names and types
@@ -1293,8 +1304,24 @@ void BlockGraph::printRaw(ostream &s) const
 
   printHeader(s);
   s << endl;
-  for(iter=list.begin();iter!=list.end();++iter)
+  if (list.empty()) return;
-    (*iter)->printRaw(s);
+  iter = list.begin();
+  FlowBlock *lastBl = *iter;
+  ++iter;
+  lastBl->printRaw(s);
+  for(;iter!=list.end();++iter) {
+    FlowBlock *curBl = *iter;
+    lastBl->printRawImpliedGoto(s, curBl);
+    curBl->printRaw(s);
+    lastBl = curBl;
+  }
+}
+
+void BlockGraph::printRawImpliedGoto(ostream &s,const FlowBlock *nextBlock) const
+
+{
+  if (list.empty()) return;
+  list.back()->printRawImpliedGoto(s, nextBlock);
 }
 
 PcodeOp *BlockGraph::firstOp(void) const
@@ -2658,6 +2685,24 @@ void BlockBasic::printRaw(ostream &s) const
   }
 }
 
+void BlockBasic::printRawImpliedGoto(ostream &s,const FlowBlock *nextBlock) const
+
+{
+  if (sizeOut() != 1) return;
+  const FlowBlock *outBlock = getOut(0);
+  if (nextBlock->getType() != t_basic) {
+    nextBlock = nextBlock->getFrontLeaf();
+    if (nextBlock == (const FlowBlock *)0) return;
+    nextBlock = nextBlock->subBlock(0);
+  }
+  if (getOut(0) == nextBlock) return;
+  if (!op.empty() && op.back()->isBranch()) return;
+  getStop().printRaw(s);
+  s << ":   \t[ goto ";
+  outBlock->printShortHeader(s);
+  s << " ]" << endl;
+}
+
 /// \brief Check for values created in \b this block that flow outside the block.
 ///
 /// The block can calculate a value for a BRANCHIND or CBRANCH and can copy values and this method will still

Ghidra/Features/Decompiler/src/decompile/cpp/block.hh

@@ -210,6 +210,14 @@ public:
   /// \param s is the given stream to write to
   virtual void printRaw(ostream &s) const {}
 
+  /// \brief If the \e out block of \b this is not the given next block, print an implied \b goto to the out block
+  ///
+  /// In order to see where \b this block is flowing to, if there is no explicit branch op, and if the next block
+  /// being printed is \e not the fallthru branch, print the destination block as an implied \b goto op.
+  /// \param s is the output stream
+  /// \param nextBlock is the given nextBlock being printed
+  virtual void printRawImpliedGoto(ostream &s,const FlowBlock *nextBlock) const {}
+
   virtual void emit(PrintLanguage *lng) const;	///<Emit the instructions in \b this FlowBlock as structured code
 
   /// \brief Get the leaf block from which \b this block exits
@@ -338,6 +346,7 @@ public:
   bool isGotoIn(int4 i) const { return ((intothis[i].label & (f_irreducible|f_goto_edge))!=0); }	///< Is the i-th incoming edge unstructured
   bool isGotoOut(int4 i) const { return ((outofthis[i].label & (f_irreducible|f_goto_edge))!=0); }	///< Is the i-th outgoing edge unstructured
   JumpTable *getJumptable(void) const;	///< Get the JumpTable associated \b this block
+  void printShortHeader(ostream &s) const;		///< Print a short identifier for the block
   static block_type nameToType(const string &name);	///< Get the block_type associated with a name string
   static string typeToName(block_type bt);		///< Get the name string associated with a block_type
   static bool compareBlockIndex(const FlowBlock *bl1,const FlowBlock *bl2);	///< Compare FlowBlock by index
@@ -380,6 +389,7 @@ public:
   virtual void scopeBreak(int4 curexit,int4 curloopexit);
   virtual void printTree(ostream &s,int4 level) const;
   virtual void printRaw(ostream &s) const;
+  void printRawImpliedGoto(ostream &s,const FlowBlock *nextBlock) const;
   virtual void emit(PrintLanguage *lng) const { lng->emitBlockGraph(this); }
   virtual PcodeOp *firstOp(void) const;
   virtual FlowBlock *nextFlowAfter(const FlowBlock *bl) const;
@@ -473,6 +483,7 @@ public:
   virtual void decodeBody(Decoder &decoder);
   virtual void printHeader(ostream &s) const;
   virtual void printRaw(ostream &s) const;
+  virtual void printRawImpliedGoto(ostream &s,const FlowBlock *nextBlock) const;
   virtual void emit(PrintLanguage *lng) const { lng->emitBlockBasic(this); }
   virtual const FlowBlock *getExitLeaf(void) const { return this; }
   virtual PcodeOp *firstOp(void) const;
@@ -515,6 +526,7 @@ public:
   virtual void printHeader(ostream &s) const;
   virtual void printTree(ostream &s,int4 level) const;
   virtual void printRaw(ostream &s) const { copy->printRaw(s); }
+  virtual void printRawImpliedGoto(ostream &s,const FlowBlock *nextBlock) const { copy->printRawImpliedGoto(s, nextBlock); }
   virtual void emit(PrintLanguage *lng) const { lng->emitBlockCopy(this); }
   virtual const FlowBlock *getExitLeaf(void) const { return this; }
   virtual PcodeOp *firstOp(void) const { return copy->firstOp(); }

Ghidra/Features/Decompiler/src/decompile/cpp/blockaction.cc

@@ -2074,18 +2074,10 @@ bool ConditionalJoin::match(BlockBasic *b1,BlockBasic *b2)
   exita = (BlockBasic *)block1->getOut(0);
   exitb = (BlockBasic *)block1->getOut(1);
   if (exita == exitb) return false;
-  if (block2->getOut(0) == exita) {
+  if (block2->getOut(0) != exita) return false;	// False exits must match
-    if (block2->getOut(1) != exitb) return false;
+  if (block2->getOut(1) != exitb) return false;	// True exits must match
-    a_in2 = block2->getOutRevIndex(0);
+  a_in2 = block2->getOutRevIndex(0);
-    b_in2 = block2->getOutRevIndex(1);
+  b_in2 = block2->getOutRevIndex(1);
-  }
-  else if (block2->getOut(0) == exitb) {
-    if (block2->getOut(1) != exita) return false;
-    a_in2 = block2->getOutRevIndex(1);
-    b_in2 = block2->getOutRevIndex(0);
-  }
-  else
-    return false;
   a_in1 = block1->getOutRevIndex(0);
   b_in1 = block1->getOutRevIndex(1);
 

Ghidra/Features/Decompiler/src/decompile/cpp/typeop.cc

@@ -591,7 +591,12 @@ void TypeOpBranch::printRaw(ostream &s,const PcodeOp *op)
 
 {
   s << name << ' ';
-  Varnode::printRaw(s,op->getIn(0));
+  const BlockBasic *parent = op->getParent();
+  if (parent != (const BlockBasic *)0 && parent->sizeOut() == 1) {
+    parent->getOut(0)->printShortHeader(s);
+  }
+  else
+    Varnode::printRaw(s,op->getIn(0));
 }
 
 TypeOpCbranch::TypeOpCbranch(TypeFactory *t) : TypeOp(t,CPUI_CBRANCH,"goto")
@@ -617,13 +622,25 @@ void TypeOpCbranch::printRaw(ostream &s,const PcodeOp *op)
 
 {
   s << name << ' ';
-  Varnode::printRaw(s,op->getIn(0));	// Print the distant (non-fallthru) destination
+  const BlockBasic *parent = op->getParent();
+  FlowBlock *falseOut = (FlowBlock *)0;
+  if (parent != (const BlockBasic *)0 && parent->sizeOut() == 2) {
+    FlowBlock *trueOut = parent->getTrueOut();
+    falseOut = parent->getFalseOut();
+    trueOut->printShortHeader(s);
+  }
+  else
+    Varnode::printRaw(s,op->getIn(0));	// Print the distant (non-fallthru) destination
   s << " if (";
   Varnode::printRaw(s,op->getIn(1));
-  if (op->isBooleanFlip()^op->isFallthruTrue())
+  if (op->isBooleanFlip())
     s << " == 0)";
   else
     s << " != 0)";
+  if (falseOut != (FlowBlock *)0) {
+    s << " else ";
+    falseOut->printShortHeader(s);
+  }
 }
 
 TypeOpBranchind::TypeOpBranchind(TypeFactory *t) : TypeOp(t,CPUI_BRANCHIND,"switch")