adjustments to resolveConstant

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

@@ -1135,7 +1135,7 @@ void Architecture::init(DocumentStorage &store)
   fillinReadOnlyFromLoader();
 }
 
-Address SegmentedResolver::resolve(uintb val,int4 sz,const Address &point)
+Address SegmentedResolver::resolve(uintb val,int4 sz,const Address &point,uintb &fullEncoding)
 
 {
   int4 innersz = segop->getInnerSize();
@@ -1145,6 +1145,7 @@ Address SegmentedResolver::resolve(uintb val,int4 sz,const Address &point)
   // (as with near pointers)
     if (segop->getResolve().space != (AddrSpace *)0) {
       uintb base = glb->context->getTrackedValue(segop->getResolve(),point);
+      fullEncoding = (base << 8 * innersz) + (val & calc_mask(innersz));
       vector<uintb> seginput;
       seginput.push_back(val);
       seginput.push_back(base);
@@ -1153,6 +1154,7 @@ Address SegmentedResolver::resolve(uintb val,int4 sz,const Address &point)
     }
   }
   else { // For anything else, consider it a "far" pointer
+    fullEncoding = val;
     int4 outersz = segop->getBaseSize();
     uintb base = (val >> 8*innersz) & calc_mask(outersz);
     val = val & calc_mask(innersz);

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

@@ -284,7 +284,7 @@ public:
   /// \param sp is the segmented space
   /// \param sop is the segment operator
   SegmentedResolver(Architecture *g,AddrSpace *sp,SegmentOp *sop) { glb=g; spc=sp; segop=sop; }
-  virtual Address resolve(uintb val,int4 sz,const Address &point);
+  virtual Address resolve(uintb val,int4 sz,const Address &point,uintb &fullEncoding);
 };
 
 /// The Translate object keeps track of address ranges for which

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

@@ -827,14 +827,14 @@ int4 ActionShadowVar::apply(Funcdata &data)
 /// \param rampoint will hold the Address of the resolved symbol
 /// \param data is the function being analyzed
 /// \return the recovered symbol or NULL
-SymbolEntry *ActionConstantPtr::isPointer(AddrSpace *spc,Varnode *vn,PcodeOp *op,Address &rampoint,Funcdata &data)
+SymbolEntry *ActionConstantPtr::isPointer(AddrSpace *spc,Varnode *vn,PcodeOp *op,Address &rampoint,uintb &fullEncoding,Funcdata &data)
 
 {
   bool needexacthit;
   Architecture *glb = data.getArch();
   Varnode *outvn;
   if (vn->getType()->getMetatype() == TYPE_PTR) { // Are we explicitly marked as a pointer
-    rampoint = glb->resolveConstant(spc,vn->getOffset(),vn->getSize(),op->getAddr());
+    rampoint = glb->resolveConstant(spc,vn->getOffset(),vn->getSize(),op->getAddr(),fullEncoding);
     needexacthit = false;
   }
   else {
@@ -881,7 +881,7 @@ SymbolEntry *ActionConstantPtr::isPointer(AddrSpace *spc,Varnode *vn,PcodeOp *op
     // Check if the constant looks like a single bit or mask
     if (bit_transitions(vn->getOffset(),vn->getSize()) < 3)
       return (SymbolEntry *)0;
-    rampoint = glb->resolveConstant(spc,vn->getOffset(),vn->getSize(),op->getAddr());
+    rampoint = glb->resolveConstant(spc,vn->getOffset(),vn->getSize(),op->getAddr(),fullEncoding);
   }
 
   if (rampoint.isInvalid()) return (SymbolEntry *)0;
@@ -943,10 +943,11 @@ int4 ActionConstantPtr::apply(Funcdata &data)
     else if ((opc == CPUI_PTRSUB)||(opc==CPUI_PTRADD))
       continue;
     Address rampoint;
-    entry = isPointer(rspc,vn,op,rampoint,data);
+    uintb fullEncoding;
+    entry = isPointer(rspc,vn,op,rampoint,fullEncoding,data);
     vn->setPtrCheck();		// Set check flag AFTER searching for symbol
     if (entry != (SymbolEntry *)0) {
-      data.spacebaseConstant(op,slot,entry,rampoint,vn->getOffset(),vn->getSize());
+      data.spacebaseConstant(op,slot,entry,rampoint,fullEncoding,vn->getSize());
       if ((opc == CPUI_INT_ADD)&&(slot==1))
 	data.opSwapInput(op,0,1);
       count += 1;

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

@@ -162,7 +162,7 @@ public:
 /// \brief Check for constants, with pointer type, that correspond to global symbols
 class ActionConstantPtr : public Action {
   int4 localcount;		///< Number of passes made for this function
-  static SymbolEntry *isPointer(AddrSpace *spc,Varnode *vn,PcodeOp *op,Address &rampoint,Funcdata &data);
+  static SymbolEntry *isPointer(AddrSpace *spc,Varnode *vn,PcodeOp *op,Address &rampoint,uintb &fullEncoding,Funcdata &data);
 public:
   ActionConstantPtr(const string &g) : Action(0,"constantptr",g) {}	///< Constructor
   virtual void reset(Funcdata &data) { localcount = 0; }

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

@@ -333,7 +333,7 @@ void Funcdata::spacebaseConstant(PcodeOp *op,int4 slot,SymbolEntry *entry,const
     outvn = outvn2;
     opInsertBefore(extraop,op);
   }
-  if (sz != origsize) {		// There is a change in size from address -> varnode
+  if (sz < origsize) {		// The new constant is smaller than the original varnode, so we extend it
     PcodeOp *zextop = newOp(1,op->getAddr());
     Varnode *outvn2 = newUniqueOut(origsize,zextop);
     opSetOpcode(zextop,CPUI_INT_ZEXT); // Create an extension to get back to original varnode size
@@ -341,6 +341,15 @@ void Funcdata::spacebaseConstant(PcodeOp *op,int4 slot,SymbolEntry *entry,const
     opInsertBefore(zextop,op);
     outvn = outvn2;
   }
+  else if (origsize < sz) {	// The new constant is bigger than the original varnode, truncate it
+    PcodeOp *subOp = newOp(2,op->getAddr());
+    Varnode *outvn3 = newUniqueOut(origsize,subOp);
+    opSetOpcode(subOp,CPUI_SUBPIECE);
+    opSetInput(subOp,outvn,0);
+    opSetInput(subOp,newConstant(4, 0), 1);	// Take least significant piece
+    opInsertBefore(subOp,op);
+    outvn = outvn3;
+  }
   opSetInput(op,outvn,slot);
 }
 

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

@@ -1403,7 +1403,8 @@ bool PrintC::pushPtrCharConstant(uintb val,const TypePointer *ct,const Varnode *
 {
   if (val==0) return false;
   AddrSpace *spc = glb->getDefaultSpace();
-  Address stringaddr = glb->resolveConstant(spc,val,ct->getSize(),op->getAddr());
+  uintb fullEncoding;
+  Address stringaddr = glb->resolveConstant(spc,val,ct->getSize(),op->getAddr(),fullEncoding);
   if (stringaddr.isInvalid()) return false;
   if (!glb->symboltab->getGlobalScope()->isReadOnly(stringaddr,1,Address()))
     return false;	     // Check that string location is readonly

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

@@ -485,15 +485,27 @@ AddrSpace *AddrSpaceManager::getSpaceByShortcut(char sc) const
   return (*iter).second;
 }
 
-Address AddrSpaceManager::resolveConstant(AddrSpace *spc,uintb val,int4 sz,const Address &point) const
+/// \brief Resolve a native constant into an Address
+///
+/// If there is a special resolver for the AddrSpace, this is invoked, otherwise
+/// basic wordsize conversion and wrapping is performed. If the address encoding is
+/// partial (as in a \e near pointer) and the full encoding can be recovered, it is passed back.
+/// \param spc is the space to generate the address from
+/// \param val is the constant encoding of the address
+/// \param sz is the size of the constant encoding
+/// \param point is the context address (for recovering full encoding info if necessary)
+/// \param fullEncoding is used to pass back the recovered full encoding of the pointer
+/// \return the formal Address associated with the encoding
+Address AddrSpaceManager::resolveConstant(AddrSpace *spc,uintb val,int4 sz,const Address &point,uintb &fullEncoding) const
 
 {
   int4 ind = spc->getIndex();
   if (ind < resolvelist.size()) {
     AddressResolver *resolve = resolvelist[ind];
     if (resolve != (AddressResolver *)0)
-      return resolve->resolve(val,sz,point);
+      return resolve->resolve(val,sz,point,fullEncoding);
   }
+  fullEncoding = val;
   val = AddrSpace::addressToByte(val,spc->getWordSize());
   val = spc->wrapOffset(val);
   return Address(spc,val);

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

@@ -147,8 +147,9 @@ public:
   /// \param val is constant to be resolved to an address
   /// \param sz is the size of \e val in context.
   /// \param point is the address at which this constant is being used
+  /// \param fullEncoding is used to hold the full pointer encoding if \b val is a partial encoding
   /// \return the resolved Address
-  virtual Address resolve(uintb val,int4 sz,const Address &point)=0;
+  virtual Address resolve(uintb val,int4 sz,const Address &point,uintb &fullEncoding)=0;
 };
 
 /// \brief A virtual space \e stack space
@@ -249,7 +250,7 @@ public:
   AddrSpace *getConstantSpace(void) const; ///< Get the constant space
   Address getConstant(uintb val) const; ///< Get a constant encoded as an Address
   Address createConstFromSpace(AddrSpace *spc) const; ///< Create a constant address encoding an address space
-  Address resolveConstant(AddrSpace *spc,uintb val,int4 sz,const Address &point) const; ///< Resolve native constant to address
+  Address resolveConstant(AddrSpace *spc,uintb val,int4 sz,const Address &point,uintb &fullEncoding) const;
   int4 numSpaces(void) const; ///< Get the number of address spaces for this processor
   AddrSpace *getSpace(int4 i) const; ///< Get an address space via its index
   AddrSpace *getNextSpaceInOrder(AddrSpace *spc) const; ///< Get the next \e contiguous address space

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

@@ -1124,13 +1124,17 @@ Datatype *TypeSpacebase::getSubType(uintb off,uintb *newoff) const
 
 {
   Scope *scope = getMap();
-  //  uintb unoff = (uintb)(intb)off; // Make sure this is a sign-extension
-  Address addr(spaceid,spaceid->wrapOffset(off));
+  off = AddrSpace::byteToAddress(off, spaceid->getWordSize());	// Convert from byte offset to address unit
+  // It should always be the case that given offset represents a full encoding of the
+  // pointer, so the point of context is unused
+  Address nullPoint;
+  uintb fullEncoding;
+  Address addr = glb->resolveConstant(spaceid, off, spaceid->getAddrSize(), nullPoint, fullEncoding);
   SymbolEntry *smallest;
 
   // Assume symbol being referenced is address tied,
   // so we use empty usepoint
-  smallest = scope->queryContainer(addr,1,Address());
+  smallest = scope->queryContainer(addr,1,nullPoint);
   
   if (smallest == (SymbolEntry *)0) {
     *newoff = 0;
@@ -1167,7 +1171,8 @@ int4 TypeSpacebase::compareDependency(const Datatype &op) const
 Address TypeSpacebase::getAddress(uintb off,int4 sz,const Address &point) const
 
 {
-  return glb->resolveConstant(spaceid,off,sz,point);
+  uintb fullEncoding;
+  return glb->resolveConstant(spaceid,off,sz,point,fullEncoding);
 }
 
 void TypeSpacebase::saveXml(ostream &s) const

Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/app/plugin/processors/sleigh/SleighLanguage.java

@@ -1378,8 +1378,8 @@ public class SleighLanguage implements Language {
 			SpecXmlUtils.encodeSignedIntegerAttribute(resBuf, "index", element.getUnique());
 
 			int size = element.getSize(); // Size in bits
-			if (size == 20) {
-				// TODO: SegmentedAddressSpace shouldn't really return 20
+			if (element instanceof SegmentedAddressSpace) {
+				// TODO: SegmentedAddressSpace shouldn't really return 21
 				size = 32;
 			}
 			if (size > 64) {