Add constants to analysis of hiding extension casts

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

@@ -166,6 +166,57 @@ int4 CastStrategyC::intPromotionType(const Varnode *vn) const
   return UNKNOWN_PROMOTION;
 }
 
+bool CastStrategyC::isExtensionCastImplied(const PcodeOp *op,const PcodeOp *readOp) const
+
+{
+  const Varnode *outVn = op->getOut();
+  if (outVn->isExplicit()) {
+
+  }
+  else {
+    if (readOp == (PcodeOp *) 0)
+      return false;
+    type_metatype metatype = outVn->getHigh()->getType()->getMetatype();
+    const Varnode *otherVn;
+    int4 slot;
+    switch (readOp->code()) {
+      case CPUI_PTRADD:
+	break;
+      case CPUI_INT_ADD:
+      case CPUI_INT_SUB:
+      case CPUI_INT_MULT:
+      case CPUI_INT_DIV:
+      case CPUI_INT_AND:
+      case CPUI_INT_OR:
+      case CPUI_INT_XOR:
+      case CPUI_INT_EQUAL:
+      case CPUI_INT_NOTEQUAL:
+      case CPUI_INT_LESS:
+      case CPUI_INT_LESSEQUAL:
+      case CPUI_INT_SLESS:
+      case CPUI_INT_SLESSEQUAL:
+	slot = readOp->getSlot(outVn);
+	otherVn = readOp->getIn(1 - slot);
+	// Check if the expression involves an explicit variable of the right integer type
+	if (otherVn->isConstant()) {
+	  // Integer tokens do not naturally indicate their size, and
+	  // integers that are bigger than the promotion size are NOT naturally extended.
+	  if (otherVn->getSize() > promoteSize)	// So if the integer is bigger than the promotion size
+	    return false;			// The extension cast on the other side must be explicit
+	}
+	else if (!otherVn->isExplicit())
+	  return false;
+	if (otherVn->getHigh()->getType()->getMetatype() != metatype)
+	  return false;
+	break;
+      default:
+	return false;
+    }
+    return true;	// Everything is integer promotion
+  }
+  return false;
+}
+
 Datatype *CastStrategyC::castStandard(Datatype *reqtype,Datatype *curtype,
 				      bool care_uint_int,bool care_ptr_uint) const
 

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

@@ -88,6 +88,16 @@ public:
   /// \return \b true if a cast is required before extending
   virtual bool checkIntPromotionForExtension(const PcodeOp *op) const=0;
 
+
+  /// \brief Is the given ZEXT/SEXT cast implied by the expression its in?
+  ///
+  /// We've already determined that the given ZEXT or SEXT op can be viewed as a natural \e cast operation.
+  /// Determine if the cast is implied by the expression its and doesn't need to be printed.
+  /// \param op is the given ZEXT or SEXT PcodeOp
+  /// \param readOp is the PcodeOp consuming the output of the extensions (or null)
+  /// \return \b true if the op as a cast does not need to be printed
+  virtual bool isExtensionCastImplied(const PcodeOp *op,const PcodeOp *readOp) const=0;
+
   /// \brief Does there need to be a visible cast between the given data-types
   ///
   /// The cast is from a \e current data-type to an \e expected data-type. NULL is returned
@@ -151,6 +161,7 @@ public:
   virtual int4 intPromotionType(const Varnode *vn) const;
   virtual bool checkIntPromotionForCompare(const PcodeOp *op,int4 slot) const;
   virtual bool checkIntPromotionForExtension(const PcodeOp *op) const;
+  virtual bool isExtensionCastImplied(const PcodeOp *op,const PcodeOp *readOp) const;
   virtual Datatype *castStandard(Datatype *reqtype,Datatype *curtype,bool care_uint_int,bool care_ptr_uint) const;
   virtual Datatype *arithmeticOutputStandard(const PcodeOp *op);
   virtual bool isSubpieceCast(Datatype *outtype,Datatype *intype,uint4 offset) const;

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

@@ -595,7 +595,7 @@ void PrintC::opIntZext(const PcodeOp *op,const PcodeOp *readOp)
 
 {
   if (castStrategy->isZextCast(op->getOut()->getHigh()->getType(),op->getIn(0)->getHigh()->getType())) {
-    if (isExtensionCastImplied(op,readOp))
+    if (option_hide_exts && castStrategy->isExtensionCastImplied(op,readOp))
       opHiddenFunc(op);
     else
       opTypeCast(op);
@@ -608,7 +608,7 @@ void PrintC::opIntSext(const PcodeOp *op,const PcodeOp *readOp)
 
 {
   if (castStrategy->isSextCast(op->getOut()->getHigh()->getType(),op->getIn(0)->getHigh()->getType())) {
-    if (isExtensionCastImplied(op,readOp))
+    if (option_hide_exts && castStrategy->isExtensionCastImplied(op,readOp))
       opHiddenFunc(op);
     else
       opTypeCast(op);
@@ -1282,61 +1282,6 @@ bool PrintC::printCharacterConstant(ostream &s,const Address &addr,int4 charsize
   return res;
 }
 
-/// \brief Is the given ZEXT/SEXT cast implied by the expression its in
-///
-/// We know that the given ZEXT or SEXT op can be viewed as a natural \e cast operation.
-/// Sometimes such a cast is implied by the expression its in, and the cast itself
-/// doesn't need to be printed.
-/// \param op is the given ZEXT or SEXT PcodeOp
-/// \param readOp is the PcodeOp consuming the output of the extensions (or null)
-/// \return \b true if the op as a cast does not need to be printed
-bool PrintC::isExtensionCastImplied(const PcodeOp *op,const PcodeOp *readOp) const
-
-{
-  if (!option_hide_exts)
-    return false;		// If hiding extensions is not on, we must always print extension
-  const Varnode *outVn = op->getOut();
-  if (outVn->isExplicit()) {
-
-  }
-  else {
-    if (readOp == (PcodeOp *) 0)
-      return false;
-    type_metatype metatype = outVn->getHigh()->getType()->getMetatype();
-    const Varnode *otherVn;
-    int4 slot;
-    switch (readOp->code()) {
-      case CPUI_PTRADD:
-	break;
-      case CPUI_INT_ADD:
-      case CPUI_INT_SUB:
-      case CPUI_INT_MULT:
-      case CPUI_INT_DIV:
-      case CPUI_INT_AND:
-      case CPUI_INT_OR:
-      case CPUI_INT_XOR:
-      case CPUI_INT_EQUAL:
-      case CPUI_INT_NOTEQUAL:
-      case CPUI_INT_LESS:
-      case CPUI_INT_LESSEQUAL:
-      case CPUI_INT_SLESS:
-      case CPUI_INT_SLESSEQUAL:
-	slot = readOp->getSlot(outVn);
-	otherVn = readOp->getIn(1 - slot);
-	// Check if the expression involves an explicit variable of the right integer type
-	if (!otherVn->isExplicit() && !otherVn->isConstant())
-	  return false;
-	if (otherVn->getHigh()->getType()->getMetatype() != metatype)
-	  return false;
-	break;
-      default:
-	return false;
-    }
-    return true;	// Everything is integer promotion
-  }
-  return false;
-}
-
 /// \brief Push a single character constant to the RPN stack
 ///
 /// For C, a character constant is usually emitted as the character in single quotes.

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

@@ -159,7 +159,6 @@ protected:
   void opHiddenFunc(const PcodeOp *op);			///< Push the given p-code op as a hidden token
   static bool hasCharTerminator(uint1 *buffer,int4 size,int4 charsize);
   bool printCharacterConstant(ostream &s,const Address &addr,int4 charsize) const;
-  bool isExtensionCastImplied(const PcodeOp *op,const PcodeOp *readOp) const;
   virtual void pushConstant(uintb val,const Datatype *ct,
 			    const Varnode *vn,const PcodeOp *op);
   virtual bool pushEquate(uintb val,int4 sz,const EquateSymbol *sym,