GP-2767 Structured pieces

Ghidra/Features/Decompiler/certification.manifest

@@ -12,6 +12,7 @@ src/decompile/.project||GHIDRA||||END|
 src/decompile/cpp/.gitignore||GHIDRA||||END|
 src/decompile/cpp/Doxyfile||GHIDRA|||Most of this file is autogenerated by doxygen which falls under the GPL - output from GPL products are NOT GPL! - mjbell4|END|
 src/decompile/cpp/Makefile||GHIDRA||||END|
+src/decompile/datatests/concat.xml||GHIDRA||||END|
 src/decompile/datatests/convert.xml||GHIDRA||||END|
 src/decompile/datatests/deadvolatile.xml||GHIDRA||||END|
 src/decompile/datatests/deindirect.xml||GHIDRA||||END|

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

@@ -313,7 +313,7 @@ int4 Architecture::getMinimumLanedRegisterSize(void) const
 
 /// The default model is used whenever an explicit model is not known
 /// or can't be determined.
-/// \param nm is the name of the model to set
+/// \param model is the ProtoModel object to make the default
 void Architecture::setDefaultModel(ProtoModel *model)
 
 {

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

@@ -2830,7 +2830,7 @@ int4 ActionNameVars::apply(Funcdata &data)
 /// and that it needs special printing.
 /// \param vn is the given Varnode
 /// \param maxref is the maximum number of references to consider before forcing explicitness
-/// \return -1 if given Varnode should be marked explicit, the number of descendants otherwise
+/// \return -1 or -2 if given Varnode should be marked explicit, the number of descendants otherwise
 int4 ActionMarkExplicit::baseExplicit(Varnode *vn,int4 maxref)
 
 {
@@ -2854,27 +2854,51 @@ int4 ActionMarkExplicit::baseExplicit(Varnode *vn,int4 maxref)
           return -1;		// Should be explicit, will be a copymarker and not printed
       }
     }
-    // (Part of) an addrtied location into itself is hopefully implicit
+    PcodeOp *useOp = vn->loneDescend();
-    bool shouldbeimplicit = true;
+    if (useOp == (PcodeOp *)0) return -1;
-    for(iter=vn->beginDescend();iter!=vn->endDescend();++iter) {
+    if (useOp->code() == CPUI_INT_ZEXT) {
-      PcodeOp *op = *iter;
+      Varnode *vnout = useOp->getOut();
-      if ((op->code()!=CPUI_INT_ZEXT)&&(op->code()!=CPUI_PIECE)) {
+      if ((!vnout->isAddrTied())||(0!=vnout->contains(*vn)))
-	shouldbeimplicit = false;
+	return -1;
-	break;
     }
-      Varnode *vnout = op->getOut();
+    else if (useOp->code() == CPUI_PIECE) {
-      if ((!vnout->isAddrTied())||(0!=vnout->contains(*vn))) {
+      Varnode *rootVn = PieceNode::findRoot(vn);
-	shouldbeimplicit = false;
+      if (vn == rootVn) return -1;
-	break;
+      Datatype *ct = rootVn->getStructuredType();
+      if (ct != (Datatype *)0) {
+	// Getting PIECEd into a structured thing.  Unless vn is a leaf, it should be implicit
+	if (def->code() != CPUI_PIECE) return -1;
+	if (vn->loneDescend() == (PcodeOp *)0) return -1;
+	Varnode *vn0 = def->getIn(0);
+	Varnode *vn1 = def->getIn(1);
+	Address addr = vn->getAddr();
+	if (!addr.getSpace()->isBigEndian())
+	  addr = addr + vn1->getSize();
+	if (addr != vn0->getAddr()) return -1;
+	addr = vn->getAddr();
+	if (addr.getSpace()->isBigEndian())
+	  addr = addr + vn0->getSize();
+	if (addr != vn1->getAddr()) return -1;
+	// If we reach here vn is a non-leaf in a CONCAT tree and should be implicit
       }
     }
-    if (!shouldbeimplicit) return -1;
+    else {
+      return -1;
+    }
   }
   else if (vn->isMapped()) {
     // If NOT addrtied but is still mapped, there must be either a first use (register) mapping
     // or a dynamic mapping causing the bit to be set. In either case, it should probably be explicit
     return -1;
   }
+  else if (vn->isProtoPartial() && def->code() != CPUI_PIECE) {
+    // Varnode is part of structure. Write to structure should be an explicit statement
+    return -1;
+  }
+  else if (def->code() == CPUI_PIECE && def->getIn(0)->isProtoPartial() && !vn->isProtoPartial()) {
+    // The base of PIECE operations building a structure
+    return -1;
+  }
   if (vn->hasNoDescend()) return -1;	// Must have at least one descendant
 
   if (def->code() == CPUI_PTRSUB) { // A dereference
@@ -5069,7 +5093,6 @@ void ActionDatabase::universalAction(Architecture *conf)
 	actprop->addRule( new RuleShiftAnd("analysis") );
 	actprop->addRule( new RuleConcatZero("analysis") );
 	actprop->addRule( new RuleConcatLeftShift("analysis") );
-	actprop->addRule( new RuleEmbed("analysis") );
 	actprop->addRule( new RuleSubZext("analysis") );
 	actprop->addRule( new RuleSubCancel("analysis") );
 	actprop->addRule( new RuleShiftSub("analysis") );
@@ -5181,6 +5204,7 @@ void ActionDatabase::universalAction(Architecture *conf)
     actcleanup->addRule( new RuleSubRight("cleanup") );
     actcleanup->addRule( new RulePtrsubCharConstant("cleanup") );
     actcleanup->addRule( new RuleExtensionPush("cleanup") );
+    actcleanup->addRule( new RulePieceStructure("cleanup") );
   }
   act->addAction( actcleanup );
 

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

@@ -364,7 +364,7 @@ public:
     return new ActionMergeRequired(getGroup());
   }
   virtual int4 apply(Funcdata &data) { 
-    data.getMerge().mergeAddrTied(); data.getMerge().mergeMarker(); return 0; }
+    data.getMerge().mergeAddrTied(); data.getMerge().groupPartials(); data.getMerge().mergeMarker(); return 0; }
 };
 
 /// \brief Try to merge an op's input Varnode to its output, if they are at the same storage location.

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

@@ -305,6 +305,12 @@ public:
   virtual void decode(Decoder &decoder);
 };
 
+/// \brief A Symbol that forces a particular \e union field at a particular point in the body of a function
+///
+/// This is an internal Symbol that users can create if they want to force a particular interpretation of a
+/// a \e union data-type.  It attaches to data-flow via the DynamicHash mechanism, which also allows it to attach
+/// to a specific read or write of the target Varnode.  Different reads (or write) of the same Varnode can have
+/// different symbols attached.  The Symbol's associated data-type will be the desired \e union to force.
 class UnionFacetSymbol : public Symbol {
   int4 fieldNum;			///< Particular field to associate with Symbol access
 public:

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

@@ -963,7 +963,8 @@ public:
 class UnknownProtoModel : public ProtoModel {
   ProtoModel *placeholderModel;		///< The model whose behavior \b this adopts as a behavior placeholder
 public:
-  UnknownProtoModel(const string &nm,ProtoModel *placeHold) : ProtoModel(nm,*placeHold) { placeholderModel = placeHold; }
+  UnknownProtoModel(const string &nm,ProtoModel *placeHold) : ProtoModel(nm,*placeHold) {
+    placeholderModel = placeHold; }	///< Constructor
   ProtoModel *getPlaceholderModel(void) const { return placeholderModel; }	///< Retrieve the placeholder model
   virtual bool isUnknown(void) const { return true; }
 };

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

@@ -101,6 +101,7 @@ void Funcdata::clear(void)
   clearJumpTables();
   // Do not clear overrides
   heritage.clear();
+  covermerge.clear();
 #ifdef OPACTION_DEBUG
   opactdbg_count = 0;
 #endif

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

@@ -414,6 +414,7 @@ public:
   void clearDeadOps(void) { obank.destroyDead(); }		///< Delete any dead PcodeOps
   void remapVarnode(Varnode *vn,Symbol *sym,const Address &usepoint);
   void remapDynamicVarnode(Varnode *vn,Symbol *sym,const Address &usepoint,uint8 hash);
+  void linkProtoPartial(Varnode *vn);				///< Find or create Symbol and a partial mapping
   Symbol *linkSymbol(Varnode *vn);				///< Find or create Symbol associated with given Varnode
   Symbol *linkSymbolReference(Varnode *vn);			///< Discover and attach Symbol to a constant reference
   Varnode *findLinkedVarnode(SymbolEntry *entry) const;	///< Find a Varnode matching the given Symbol mapping

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

@@ -813,7 +813,8 @@ void Funcdata::calcNZMask(void)
 /// The caller can elect to update data-type information as well, where Varnodes
 /// and their associated HighVariables have their data-type finalized based symbols.
 /// \param lm is the Symbol scope within which to search for mapped Varnodes
-/// \param updataDatatypes is \b true if the caller wants to update data-types
+/// \param updateDatatypes is \b true if the caller wants to update data-types
+/// \param unmappedAliasCheck is \b true if an alias check should be performed on unmapped Varnodes
 /// \return \b true if any Varnode was updated
 bool Funcdata::syncVarnodesWithSymbols(const ScopeLocal *lm,bool updateDatatypes,bool unmappedAliasCheck)
 
@@ -883,16 +884,7 @@ Datatype *Funcdata::checkSymbolType(Varnode *vn)
   if (curType->getSize() == vn->getSize())
     return (Datatype *)0;
   int4 curOff = (vn->getAddr().getOffset() - entry->getAddr().getOffset()) + entry->getOffset();
-  // Drill down until we hit something that isn't a containing structure
+  return glb->types->getExactPiece(curType, curOff, vn->getSize());
-  while(curType != (Datatype *)0 && curType->getMetatype() == TYPE_STRUCT && curType->getSize() > vn->getSize()) {
-    uintb newOff;
-    curType = curType->getSubType(curOff, &newOff);
-    curOff = newOff;
-  }
-  if (curType == (Datatype *)0 || curType->getSize() <= vn->getSize() || curType->getMetatype() != TYPE_UNION)
-    return (Datatype *)0;
-  // If we hit a containing union
-  return glb->types->getTypePartialUnion((TypeUnion *)curType, curOff, vn->getSize());
 }
 
 /// A Varnode overlaps the given SymbolEntry.  Make sure the Varnode is part of the variable
@@ -1033,6 +1025,25 @@ void Funcdata::remapDynamicVarnode(Varnode *vn,Symbol *sym,const Address &usepoi
   vn->setSymbolEntry(entry);
 }
 
+/// PIECE operations put the given Varnode into a larger structure.  Find the resulting
+/// whole Varnode, make sure it has a symbol assigned, and then assign the same symbol
+/// to the given Varnode piece.  If the given Varnode has been merged with something
+/// else or the whole Varnode can't be found, do nothing.
+void Funcdata::linkProtoPartial(Varnode *vn)
+
+{
+  HighVariable *high = vn->getHigh();
+  if (high->getSymbol() != (Symbol *)0) return;
+  Varnode *rootVn = PieceNode::findRoot(vn);
+  if (rootVn == vn) return;
+
+  Varnode *nameRep = rootVn->getHigh()->getNameRepresentative();
+  Symbol *sym = linkSymbol(nameRep);
+  if (sym == (Symbol *)0) return;
+  SymbolEntry *entry = sym->getFirstWholeMap();
+  vn->setSymbolEntry(entry);
+}
+
 /// The Symbol is really attached to the Varnode's HighVariable (which must exist).
 /// The only reason a Symbol doesn't get set is if, the HighVariable
 /// is global and there is no pre-existing Symbol.  (see mapGlobals())
@@ -1041,6 +1052,8 @@ void Funcdata::remapDynamicVarnode(Varnode *vn,Symbol *sym,const Address &usepoi
 Symbol *Funcdata::linkSymbol(Varnode *vn)
 
 {
+  if (vn->isProtoPartial())
+    linkProtoPartial(vn);
   HighVariable *high = vn->getHigh();
   SymbolEntry *entry;
   uint4 fl = 0;

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

@@ -112,9 +112,18 @@ bool Merge::mergeTestRequired(HighVariable *high_out,HighVariable *high_in)
       return false;			// Map to different parts of same symbol
   }
 
+  if (high_out->piece != (VariablePiece *)0 || high_in->piece != (VariablePiece *)0) {
     // Currently don't allow merging of variables that are in separate overlapping collections
     if (high_out->piece != (VariablePiece *)0 && high_in->piece != (VariablePiece *)0)
       return false;
+    if (symbolIn != symbolOut) {	// If we know symbols are involved, and not both the same symbol
+      // Treat piece as if it were a separate symbol
+      if (symbolIn != (Symbol *)0 && high_out->piece != (VariablePiece *)0)
+	return false;	// effectively different symbols
+      if (symbolOut != (Symbol *)0 && high_in->piece != (VariablePiece *)0)
+	return false;	// effectively different symbols
+    }
+  }
 
   return true;
 }
@@ -184,7 +193,19 @@ bool Merge::mergeTestSpeculative(HighVariable *high_out,HighVariable *high_in)
   return true;
 }
 
-/// \brief A test if the given Varnode can ever be merged
+/// \brief Test if the given Varnode that \e must be merged, \e can be merged.
+///
+/// If it cannot be merged, throw an exception.
+/// \param vn is the given Varnode
+void Merge::mergeTestMust(Varnode *vn)
+
+{
+  if (vn->hasCover() && !vn->isImplied())
+    return;
+  throw LowlevelError("Cannot force merge of range");
+}
+
+/// \brief Test if the given Varnode can ever be merged.
 ///
 /// Some Varnodes (constants, annotations, implied, spacebase) are never merged with another
 /// Varnode.
@@ -196,6 +217,7 @@ bool Merge::mergeTestBasic(Varnode *vn)
   if (vn == (Varnode *)0) return false;
   if (!vn->hasCover()) return false;
   if (vn->isImplied()) return false;
+  if (vn->isProtoPartial()) return false;
   if (vn->isSpacebase()) return false;
   return true;
 }
@@ -242,18 +264,12 @@ void Merge::mergeRangeMust(VarnodeLocSet::const_iterator startiter,VarnodeLocSet
   Varnode *vn;
 
   vn = *startiter++;
-  if (!mergeTestBasic(vn)) {
+  mergeTestMust(vn);
-    if (!vn->isSpacebase())
-      throw LowlevelError("Cannot force merge of range");
-  }
   high = vn->getHigh();
   for(;startiter!=enditer;++startiter) {
     vn = *startiter;
     if (vn->getHigh() == high) continue;
-    if (!mergeTestBasic(vn)) {
+    mergeTestMust(vn);
-      if (!vn->isSpacebase())
-	throw LowlevelError("Cannot force merge of range");
-    }
     if (!merge(high,vn->getHigh(),false))
       throw LowlevelError("Forced merge caused intersection");
   }
@@ -933,6 +949,19 @@ void Merge::mergeMultiEntry(void)
   }
 }
 
+/// \brief Run through CONCAT tree roots and group each tree
+///
+void Merge::groupPartials(void)
+
+{
+  for(int4 i=0;i<protoPartial.size();++i) {
+    PcodeOp *op = protoPartial[i];
+    if (op->isDead()) continue;
+    if (!op->isPartialRoot()) continue;
+    groupPartialRoot(op->getOut());
+  }
+}
+
 /// \brief Speculatively merge Varnodes that are input/output to the same p-code op
 ///
 /// If a single p-code op has an input and output HighVariable that share the same data-type,
@@ -1324,6 +1353,37 @@ void Merge::processHighRedundantCopy(HighVariable *high)
   }
 }
 
+/// \brief Group the different nodes of a CONCAT tree into a VariableGroup
+///
+/// This formally labels all the Varnodes in the tree as overlapping pieces of the same variable.
+/// The tree is reconstructed from the root Varnode.
+/// \param vn is the root Varnode
+void Merge::groupPartialRoot(Varnode *vn)
+
+{
+  HighVariable *high = vn->getHigh();
+  if (high->numInstances() != 1) return;
+  vector<PieceNode> pieces;
+
+  int4 baseOffset = 0;
+  SymbolEntry *entry = vn->getSymbolEntry();
+  if (entry != (SymbolEntry *)0) {
+    baseOffset = entry->getOffset();
+  }
+
+  PieceNode::gatherPieces(pieces, vn, vn->getDef(), baseOffset);
+  for(int4 i=0;i<pieces.size();++i) {
+    Varnode *nodeVn = pieces[i].getVarnode();
+    // Make sure each node is still marked and hasn't merged with anything else
+    if (!nodeVn->isProtoPartial()) return;
+    if (nodeVn->getHigh()->numInstances() != 1) return;
+  }
+  for(int4 i=0;i<pieces.size();++i) {
+    Varnode *nodeVn = pieces[i].getVarnode();
+    nodeVn->getHigh()->groupWith(pieces[i].getTypeOffset() - baseOffset,high);
+  }
+}
+
 /// \brief Try to reduce/eliminate COPYs produced by the merge trimming process
 ///
 /// In order to force merging of certain Varnodes, extra COPY operations may be inserted
@@ -1396,12 +1456,19 @@ void Merge::markInternalCopies(void)
       h1 = op->getOut()->getHigh();
       h2 = op->getIn(0)->getHigh();
       h3 = op->getIn(1)->getHigh();
+      if (!h2->isPartial()) break;
+      if (!h3->isPartial()) break;
+      v2 = h2->getPartial();
+      v3 = h3->getPartial();
+      if (v2->isAddrTied()) {
 	if (!h1->isAddrTied()) break;
-      if (!h2->isAddrTied()) break;
-      if (!h3->isAddrTied()) break;
 	v1 = h1->getTiedVarnode();
-      v2 = h2->getTiedVarnode();
+      }
-      v3 = h3->getTiedVarnode();
+      else {
+	if (op->getIn(0) != v2) break;
+	if (op->getIn(1) != v3) break;
+	v1 = op->getOut();
+      }
       if (v3->overlap(*v1) != 0) break;
       if (v2->overlap(*v1) != v3->getSize()) break;
       data.opMarkNonPrinting(op);
@@ -1409,10 +1476,16 @@ void Merge::markInternalCopies(void)
     case CPUI_SUBPIECE:
       h1 = op->getOut()->getHigh();
       h2 = op->getIn(0)->getHigh();
-      if (!h1->isAddrTied()) break;
+      if (!h1->isPartial()) break;
+      v1 = h1->getPartial();
+      if (v1->isAddrTied()) {
 	if (!h2->isAddrTied()) break;
-      v1 = h1->getTiedVarnode();
 	v2 = h2->getTiedVarnode();
+      }
+      else {
+	if (!h1->sameGroup(h2)) break;
+	v2 = op->getIn(0);
+      }
       val = op->getIn(1)->getOffset();
       if (v1->overlap(*v2) != val) break;
       data.opMarkNonPrinting(op);
@@ -1432,6 +1505,17 @@ void Merge::markInternalCopies(void)
 #endif
 }
 
+/// \brief Register an unmapped CONCAT stack with the merge process
+///
+/// The given Varnode must be the root of a tree of CPUI_PIECE operations as produced by
+/// PieceNode::gatherPieces.  These will be grouped together into a single variable.
+/// \param vn is the given root Varnode
+void Merge::registerProtoPartialRoot(Varnode *vn)
+
+{
+  protoPartial.push_back(vn->getDef());
+}
+
 /// \brief Translate any intersection tests for \e high2 into tests for \e high1
 ///
 /// The two variables will be merged and \e high2, as an object, will be freed.
@@ -1548,6 +1632,17 @@ void Merge::purgeHigh(HighVariable *high)
   highedgemap.erase(iterfirst,iterlast);
 }
 
+/// \brief Clear the any cached data from the last merge process
+///
+/// Free up resources used by cached intersection tests etc.
+void Merge::clear(void)
+
+{
+  highedgemap.clear();
+  copyTrims.clear();
+  protoPartial.clear();
+}
+
 /// \brief Test the intersection of two HighVariables and cache the result
 ///
 /// If the Covers of the two variables intersect, this routine returns \b true. To avoid

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

@@ -81,6 +81,7 @@ class Merge {
   Funcdata &data;		///< The function containing the Varnodes to be merged
   map<HighEdge,bool> highedgemap; ///< A cache of intersection tests, sorted by HighVariable pair
   vector<PcodeOp *> copyTrims;	///< COPY ops inserted to facilitate merges
+  vector<PcodeOp *> protoPartial;	///< Roots of unmapped CONCAT trees
   bool updateHigh(HighVariable *a); ///< Make sure given HighVariable's Cover is up-to-date
   void purgeHigh(HighVariable *high); ///< Remove cached intersection tests for a given HighVariable
   static void gatherBlockVarnodes(HighVariable *a,int4 blk,const Cover &cover,vector<Varnode *> &res);
@@ -89,6 +90,7 @@ class Merge {
   static bool mergeTestRequired(HighVariable *high_out,HighVariable *high_in);
   static bool mergeTestAdjacent(HighVariable *high_out,HighVariable *high_in);
   static bool mergeTestSpeculative(HighVariable *high_out,HighVariable *high_in);
+  static void mergeTestMust(Varnode *vn);
   static bool mergeTestBasic(Varnode *vn);
   static void findSingleCopy(HighVariable *high,vector<Varnode *> &singlelist);
   static bool compareHighByBlock(const HighVariable *a,const HighVariable *b);
@@ -116,8 +118,10 @@ class Merge {
   void markRedundantCopies(HighVariable *high,vector<PcodeOp *> &copy,int4 pos,int4 size);
   void processHighDominantCopy(HighVariable *high);
   void processHighRedundantCopy(HighVariable *high);
+  void groupPartialRoot(Varnode *vn);
 public:
   Merge(Funcdata &fd) : data(fd) {} ///< Construct given a specific function
+  void clear(void);
   bool intersection(HighVariable *a,HighVariable *b);
   bool inflateTest(Varnode *a,HighVariable *high);
   void inflate(Varnode *a,HighVariable *high);
@@ -127,11 +131,13 @@ public:
   void mergeByDatatype(VarnodeLocSet::const_iterator startiter,VarnodeLocSet::const_iterator enditer);
   void mergeAddrTied(void);
   void mergeMarker(void);
+  void groupPartials(void);
   void mergeAdjacent(void);
   void mergeMultiEntry(void);
   bool hideShadows(HighVariable *high);
   void processCopyTrims(void);
   void markInternalCopies(void);
+  void registerProtoPartialRoot(Varnode *vn);
 #ifdef MERGEMULTI_DEBUG
   void verifyHighCovers(void);
 #endif

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

@@ -750,6 +750,90 @@ int4 PcodeOp::compareOrder(const PcodeOp *bop) const
   return 0;
 }
 
+/// \brief Determine if a Varnode is a leaf within the CONCAT tree rooted at the given Varnode
+///
+/// The CONCAT tree is the maximal set of Varnodes that are all inputs to CPUI_PIECE operations,
+/// with no other uses, and that all ultimately flow to the root Varnode.  This method tests
+/// whether a Varnode is a leaf of this tree.
+/// \param rootVn is the given root of the CONCAT tree
+/// \param vn is the Varnode to test as a leaf
+/// \param typeOffset is byte offset of the test Varnode within fully concatenated value
+/// \return \b true is the test Varnode is a leaf of the tree
+bool PieceNode::isLeaf(Varnode *rootVn,Varnode *vn,int4 typeOffset)
+
+{
+  if (vn->isMapped() && rootVn->getSymbolEntry() != vn->getSymbolEntry()) {
+    return true;
+  }
+  if (!vn->isWritten()) return true;
+  PcodeOp *def = vn->getDef();
+  if (def->code() != CPUI_PIECE) return true;
+  PcodeOp *op = vn->loneDescend();
+  if (op == (PcodeOp *)0) return true;
+  if (vn->isAddrTied()) {
+    Address addr = rootVn->getAddr() + typeOffset;
+    if (vn->getAddr() != addr) return true;
+  }
+  return false;
+}
+
+/// Find the root of the CONCAT tree of Varnodes marked either isProtoPartial() or isAddrTied().
+/// This will be the maximal Varnode that containing the given Varnode (as storage), with a
+/// backward path to it through PIECE operations. All Varnodes along the path, except the root, will be
+/// marked as isProtoPartial() or isAddrTied().
+/// \return the root of the CONCAT tree
+Varnode *PieceNode::findRoot(Varnode *vn)
+
+{
+  while(vn->isProtoPartial() || vn->isAddrTied()) {
+    list<PcodeOp *>::const_iterator iter = vn->beginDescend();
+    PcodeOp *pieceOp = (PcodeOp *)0;
+    while(iter != vn->endDescend()) {
+      PcodeOp *op = *iter;
+      ++iter;
+      if (op->code() != CPUI_PIECE) continue;
+      int4 slot = op->getSlot(vn);
+      Address addr = op->getOut()->getAddr();
+      if (addr.getSpace()->isBigEndian() == (slot == 1))
+	addr = addr + op->getIn(1-slot)->getSize();
+      if (addr == vn->getAddr()) {
+	if (pieceOp != (PcodeOp *)0) {		// If there is more than one valid PIECE
+	  if (op->compareOrder(pieceOp))	// Attach this to earliest one
+	    pieceOp = op;
+	}
+	else
+	  pieceOp = op;
+      }
+    }
+    if (pieceOp == (PcodeOp *)0)
+      break;
+    vn = pieceOp->getOut();
+  }
+  return vn;
+}
+
+/// \brief Build the CONCAT tree rooted at the given Varnode
+///
+/// Recursively walk backwards from the root through CPUI_PIECE operations, stopping if a Varnode
+/// is deemed a leaf.  Collect all Varnodes involved in the tree in a list.  For each Varnode in the tree,
+/// record whether it is leaf and also calculate its offset within the data-type attached to the root.
+/// \param stack holds the markup for each node of the tree
+/// \param rootVn is the given root of the tree
+/// \param op is the current PIECE op to explore as part of the tree
+/// \param baseOffset is the offset associated with the output of the current PIECE op
+void PieceNode::gatherPieces(vector<PieceNode> &stack,Varnode *rootVn,PcodeOp *op,int4 baseOffset)
+
+{
+  for(int4 i=0;i<2;++i) {
+    Varnode *vn = op->getIn(i);
+    int4 offset = (rootVn->getSpace()->isBigEndian() == (i==1)) ? baseOffset + op->getIn(1-i)->getSize() : baseOffset;
+    bool res = isLeaf(rootVn,vn,offset);
+    stack.emplace_back(op,i,offset,res);
+    if (!res)
+      gatherPieces(stack,rootVn,vn->getDef(),offset);
+  }
+}
+
 /// Add the PcodeOp to the list of ops with the same op-code. Currently only certain
 /// op-codes have a dedicated list.
 /// \param op is the given PcodeOp

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

@@ -111,7 +111,8 @@ public:
     incidental_copy = 0x10,	///< Treat this as \e incidental for parameter recovery algorithms
     is_cpool_transformed = 0x20, ///< Have we checked for cpool transforms
     stop_type_propagation = 0x40,	///< Stop data-type propagation into output from descendants
-    hold_output = 0x80		///< Output varnode (of call) should not be removed if it is unread
+    hold_output = 0x80,		///< Output varnode (of call) should not be removed if it is unread
+    concat_root = 0x100		///< Output of \b this is root of a CONCAT tree
   };
 private:
   TypeOp *opcode;		///< Pointer to class providing behavioral details of the operation
@@ -212,6 +213,8 @@ public:
   void clearStopTypePropagation(void) { addlflags &= ~stop_type_propagation; }	///< Allow data-type propagation from below
   bool holdOutput(void) const { return ((addlflags&hold_output)!=0); }	///< If \b true, do not remove output as dead code
   void setHoldOutput(void) { addlflags |= hold_output; }	///< Prevent output from being removed as dead code
+  bool isPartialRoot(void) const { return ((addlflags&concat_root)!=0); }	///< Output is root of CONCAT tree
+  void setPartialRoot(void) { addlflags |= concat_root; }	///< Mark \b this as root of CONCAT tree
   bool stopsCopyPropagation(void) const { return ((flags&no_copy_propagation)!=0); }	///< Does \b this allow COPY propagation
   void setStopCopyPropagation(void) { flags |= no_copy_propagation; }	///< Stop COPY propagation through inputs
   /// \brief Return \b true if this LOADs or STOREs from a dynamic \e spacebase pointer
@@ -251,6 +254,30 @@ struct PcodeOpNode {
   PcodeOpNode(PcodeOp *o,int4 s) { op = o; slot = s; }	///< Constructor
 };
 
+/// \brief A node in a tree structure of CPUI_PIECE operations
+///
+/// If a group of Varnodes are concatenated into a larger structure, this object is used to explicitly gather
+/// the PcodeOps (and Varnodes) in the data-flow and view them as a unit. In a properly formed tree, for each
+/// CPUI_PIECE operation, the addresses of the input Varnodes and the output Varnode align according to the
+/// concatenation. Internal Varnodes can have only one descendant, but the leaf and the root Varnodes
+/// can each have multiple descendants
+class PieceNode {
+  PcodeOp *pieceOp;	///< CPUI_PIECE operation combining this particular Varnode piece
+  int4 slot;		///< The particular slot of this Varnode within CPUI_PIECE
+  int4 typeOffset;	///< Byte offset into structure/array
+  bool leaf;		///< \b true if this is a leaf of the tree structure
+public:
+  PieceNode(PcodeOp *op,int4 sl,int4 off,bool l) { pieceOp=op; slot=sl; typeOffset=off; leaf = l; }	///< Constructor
+  bool isLeaf(void) const { return leaf; }		///< Return \b true if \b this node is a leaf of the tree structure
+  int4 getTypeOffset(void) const { return typeOffset; }	///< Get the byte offset of \b this node into the data-type
+  int4 getSlot(void) const { return slot; }	///< Get the input slot associated with \b this node
+  PcodeOp *getOp(void) const { return pieceOp; }	///< Get the PcodeOp reading \b this piece
+  Varnode *getVarnode(void) const { return pieceOp->getIn(slot); }	///< Get the Varnode representing \b this piece
+  static bool isLeaf(Varnode *rootVn,Varnode *vn,int4 typeOffset);
+  static Varnode *findRoot(Varnode *vn);
+  static void gatherPieces(vector<PieceNode> &stack,Varnode *rootVn,PcodeOp *op,int4 baseOffset);
+};
+
 /// A map from sequence number (SeqNum) to PcodeOp
 typedef map<SeqNum,PcodeOp *> PcodeOpTree;
 

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

@@ -758,15 +758,30 @@ void PrintC::opSubpiece(const PcodeOp *op)
 
 {
   if (op->doesSpecialPrinting()) {		// Special printing means it is a field extraction
+    const Varnode *vn = op->getIn(0);
+    Datatype *ct = vn->getHighTypeReadFacing(op);
+    if (ct->isPieceStructured()) {
       int4 offset;
-    Datatype *ct;
+      int4 byteOff = TypeOpSubpiece::computeByteOffsetForComposite(op);
-    const TypeField *field = TypeOpSubpiece::testExtraction(true, op, ct, offset);
+      const TypeField *field = ct->findTruncation(byteOff,op->getOut()->getSize(),op,1,offset);	// Use artificial slot
-    if (field != (const TypeField *)0 && offset == 0) {
+      if (field != (const TypeField*)0 && offset == 0) {		// A formal structure field
 	pushOp(&object_member,op);
-      pushVn(op->getIn(0), op, mods);
+	pushVn(vn,op,mods);
 	pushAtom(Atom(field->name,fieldtoken,EmitMarkup::no_color,ct,field->ident,op));
 	return;
       }
+      else if (vn->isExplicit() && vn->getHigh()->getSymbolOffset() == -1) {	// An explicit, entire, structured object
+	Symbol *sym = vn->getHigh()->getSymbol();
+	if (sym != (Symbol *)0) {
+	  int4 sz = op->getOut()->getSize();
+	  int4 off = (int4)op->getIn(1)->getOffset();
+	  off = vn->getSpace()->isBigEndian() ? vn->getSize() - (sz + off) : off;
+	  pushPartialSymbol(sym, off, sz, vn, op, -1);
+	  return;
+	}
+      }
+      // Fall thru to functional printing
+    }
   }
   if (castStrategy->isSubpieceCast(op->getOut()->getHighTypeDefFacing(),
 				   op->getIn(0)->getHighTypeReadFacing(op),
@@ -1930,13 +1945,9 @@ void PrintC::pushPartialSymbol(const Symbol *sym,int4 off,int4 sz,
       stack.emplace_back();
       PartialSymbolEntry &entry(stack.back());
       entry.token = &object_member;
-      ostringstream s;
       if (sz == 0)
 	sz = ct->getSize() - off;
-      // Special notation for subpiece which is neither
+      entry.fieldname = unnamedField(off, sz);	// If nothing else works, generate artificial field name
-      // array entry nor struct field
-      s << '_' << dec << off << '_' << sz << '_';
-      entry.fieldname = s.str();
       entry.field = (const TypeField *)0;
       entry.hilite = EmitMarkup::no_color;
       ct = (Datatype *)0;

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

@@ -693,6 +693,19 @@ void PrintLanguage::setIntegerFormat(const string &nm)
   mods |= mod;			// Set any new force
 }
 
+/// This is used if a value is extracted from a structured data-type, but the natural name is not available.
+/// An artificial name is generated given just the offset into the data-type and the size in bytes.
+/// \param off is the byte offset into the data-type
+/// \param size is the number of bytes in the extracted value
+/// \return a string describing the artificial field
+string PrintLanguage::unnamedField(int4 off,int4 size)
+
+{
+  ostringstream s;
+  s << '_' << dec << off << '_' << size << '_';
+  return s.str();
+}
+
 /// Count '0' and '9' digits base 10. Count '0' and 'f' digits base 16.
 /// The highest count is the preferred base.
 /// \param val is the given integer

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

@@ -554,6 +554,7 @@ public:
   virtual void opInsertOp(const PcodeOp *op)=0;				///< Emit an INSERT operator
   virtual void opExtractOp(const PcodeOp *op)=0;			///< Emit an EXTRACT operator
   virtual void opPopcountOp(const PcodeOp *op)=0;			///< Emit a POPCOUNT operator
+  virtual string unnamedField(int4 off,int4 size);			///< Generate an artificial field name
 
   static int4 mostNaturalBase(uintb val); 			///< Determine the most natural base for an integer
   static void formatBinary(ostream &s,uintb val);		///< Print a number in binary form

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

@@ -4964,89 +4964,6 @@ int4 RuleHumptyOr::applyOp(PcodeOp *op,Funcdata &data)
   return 1;
 }
 
-/// \class RuleEmbed
-/// \brief Simplify PIECE intended as embedding: `concat(V, sub(W,0))  =>  W & 0xff | (zext(W) << 8)`
-///
-/// There is a complementary form:
-///  `concat(sub(V,c),W)  =>  (V & 0xff00) | zext(W)`
-void RuleEmbed::getOpList(vector<uint4> &oplist) const
-
-{
-  oplist.push_back(CPUI_PIECE);
-}
-
-int4 RuleEmbed::applyOp(PcodeOp *op,Funcdata &data)
-
-{
-  // Beware of humpty dumpty
-  Varnode *a,*subout,*x;
-  PcodeOp *subop;
-  int4 i;
-
-  if (op->getOut()->getSize() > sizeof(uintb)) return 0;	// FIXME: Can't exceed uintb precision
-  for(i=0;i<2;++i) {
-    subout = op->getIn(i);
-    if (!subout->isWritten()) continue;
-    subop = subout->getDef();
-    if (subop->code() != CPUI_SUBPIECE) continue;
-    int4 c = subop->getIn(1)->getOffset();
-    a = subop->getIn(0);
-    if (a->isFree()) continue;
-    if (a->getSize() != op->getOut()->getSize()) continue;
-    x = op->getIn(1-i);
-    if (x->isFree()) continue;
-    if (i==0) {
-      if (subout->getSize()+c != a->getSize()) continue; // Not hi SUB
-    }
-    else {
-      if (c != 0) continue;	// Not lo SUB
-    }
-
-    if (x->isWritten()) {	// Check for humptydumpty
-      PcodeOp *othersub = x->getDef();
-      if (othersub->code() == CPUI_SUBPIECE) {
-	if (othersub->getIn(0)==a) {
-	  int4 d = othersub->getIn(1)->getOffset();
-	  if ((i==0)&&(d==0)) continue;
-	  if ((i==1)&&(d==subout->getSize())) continue;
-	}
-      }
-    }
-
-    uintb mask = calc_mask(subout->getSize());
-    mask <<= 8*c;
-
-    // Construct mask
-    PcodeOp *andop = data.newOp(2,op->getAddr());
-    data.opSetOpcode(andop,CPUI_INT_AND);
-    data.newUniqueOut(a->getSize(),andop);
-    data.opSetInput(andop,a,0);
-    data.opSetInput(andop,data.newConstant(a->getSize(),mask),1);
-    data.opInsertBefore(andop,op);
-    // Extend x
-    PcodeOp *extop = data.newOp(1,op->getAddr());
-    data.opSetOpcode(extop,CPUI_INT_ZEXT);
-    data.newUniqueOut(a->getSize(),extop);
-    data.opSetInput(extop,x,0);
-    data.opInsertBefore(extop,op);
-    x = extop->getOut();
-    if (i==1) {			// Shift x into position
-      PcodeOp *shiftop = data.newOp(2,op->getAddr());
-      data.opSetOpcode(shiftop,CPUI_INT_LEFT);
-      data.newUniqueOut(a->getSize(),shiftop);
-      data.opSetInput(shiftop,x,0);
-      data.opSetInput(shiftop,data.newConstant(4,8*subout->getSize()),1);
-      data.opInsertBefore(shiftop,op);
-      x = shiftop->getOut();
-    }
-    data.opSetOpcode(op,CPUI_INT_OR);
-    data.opSetInput(op,andop->getOut(),0);
-    data.opSetInput(op,x,1);
-    return 1;
-  }
-  return 0;
-}
-
 /// \class RuleSwitchSingle
 /// \brief Convert BRANCHIND with only one computed destination to a BRANCH
 void RuleSwitchSingle::getOpList(vector<uint4> &oplist) const
@@ -6696,12 +6613,9 @@ void RuleSubRight::getOpList(vector<uint4> &oplist) const
 int4 RuleSubRight::applyOp(PcodeOp *op,Funcdata &data)
 
 {
-  Datatype *parent;
-  int4 offset;
-
   if (op->doesSpecialPrinting())
     return 0;
-  if (TypeOpSubpiece::testExtraction(false, op, parent, offset) != (const TypeField *)0) {
+  if (op->getIn(0)->getTypeReadFacing(op)->isPieceStructured()) {
     data.opMarkSpecialPrint(op);	// Print this as a field extraction
     return 0;
   }
@@ -6899,6 +6813,251 @@ int4 RuleExtensionPush::applyOp(PcodeOp *op,Funcdata &data)
   return 1;
 }
 
+/// \brief Find the base structure or array data-type that the given Varnode is part of
+///
+/// If the Varnode's data-type is already a structure or array, return that data-type.
+/// If the Varnode is part of a known symbol, use that data-type.
+/// The starting byte offset of the given Varnode within the structure or array is passed back.
+/// \param vn is the given Varnode
+/// \param baseOffset is used to pass back the starting offset
+/// \return the structure or array data-type, or null otherwise
+Datatype *RulePieceStructure::determineDatatype(Varnode *vn,int4 &baseOffset)
+
+{
+  Datatype *ct = vn->getStructuredType();
+  if (ct == (Datatype *)0)
+    return ct;
+
+  if (ct->getSize() != vn->getSize()) {			// vn is a partial
+    SymbolEntry *entry = vn->getSymbolEntry();
+    baseOffset = vn->getAddr().overlap(0,entry->getAddr(),ct->getSize());
+    if (baseOffset < 0)
+      return (Datatype*)0;
+    baseOffset += entry->getOffset();
+    // Find concrete sub-type that matches the size of the Varnode
+    Datatype *subType = ct;
+    uintb subOffset = baseOffset;
+    while(subType != (Datatype *)0 && subType->getSize() > vn->getSize()) {
+      subType = subType->getSubType(subOffset, &subOffset);
+    }
+    if (subType != (Datatype *)0 && subType->getSize() == vn->getSize() && subOffset == 0) {
+      // If there is a concrete sub-type
+      if (!subType->isPieceStructured())	// and the concrete sub-type is not a structured type itself
+	return (Datatype *)0;	// don't split out CONCAT forming the sub-type
+    }
+  }
+  else {
+    baseOffset = 0;
+  }
+  return ct;
+}
+
+/// \brief For a structured data-type, determine if the given range spans multiple elements
+///
+/// Return true unless the range falls within a single non-structured element.
+/// \param ct is the structured data-type
+/// \param offset is the start of the given range
+/// \param size is the number of bytes in the range
+/// \return \b true if the range spans multiple elements
+bool RulePieceStructure::spanningRange(Datatype *ct,int4 offset,int4 size)
+
+{
+  if (offset + size > ct->getSize()) return false;
+  uintb newOff = offset;
+  for(;;) {
+    ct = ct->getSubType(newOff, &newOff);
+    if (ct == (Datatype *)0) return true;	// Don't know what it spans, assume multiple
+    if ((int4)newOff + size > ct->getSize()) return true;	// Spans more than 1
+    if (!ct->isPieceStructured()) break;
+  }
+  return false;
+}
+
+/// \brief Convert an INT_ZEXT operation to a PIECE with a zero constant as the first parameter
+///
+/// The caller provides a parent data-type and an offset into it corresponding to the \e output of the INT_ZEXT.
+/// The op is converted to a PIECE with a 0 Varnode, which will be assigned a data-type based on
+/// the parent data-type and a computed offset.
+/// \param zext is the INT_ZEXT operation
+/// \param ct is the parent data-type
+/// \param offset is the byte offset of the \e output within the parent data-type
+/// \param data is the function containing the operation
+/// \return true if the INT_ZEXT was successfully converted
+bool RulePieceStructure::convertZextToPiece(PcodeOp *zext,Datatype *ct,int4 offset,Funcdata &data)
+
+{
+  Varnode *outvn = zext->getOut();
+  Varnode *invn = zext->getIn(0);
+  if (invn->isConstant()) return false;
+  int4 sz = outvn->getSize() - invn->getSize();
+  if (sz > sizeof(uintb)) return false;
+  offset += outvn->getSpace()->isBigEndian() ? 0 : invn->getSize();
+  uintb newOff = offset;
+  while(ct != (Datatype *)0 && ct->getSize() > sz) {
+    ct = ct->getSubType(newOff, &newOff);
+  }
+  Varnode *zerovn = data.newConstant(sz, 0);
+  if (ct != (Datatype *)0 && ct->getSize() == sz)
+    zerovn->updateType(ct, false, false);
+  data.opSetOpcode(zext, CPUI_PIECE);
+  data.opInsertInput(zext, zerovn, 0);
+  if (invn->getType()->needsResolution())
+    data.inheritResolution(invn->getType(), zext, 1, zext, 0);	// Transfer invn's resolution to slot 1
+  return true;
+}
+
+/// \brief Search for leaves in the CONCAT tree defined by an INT_ZEXT operation and convert them to PIECE
+///
+/// The CONCAT tree can be extended through an INT_ZEXT, if the extensions output crosses multiple fields of
+/// the parent data-type.  We check this and replace the INT_ZEXT with PIECE if appropriate.
+/// \param stack is the node container for the CONCAT tree
+/// \param structuredType is the parent data-type for the tree
+/// \param data is the function containing the tree
+/// \return \b true if any INT_ZEXT replacement was performed
+bool RulePieceStructure::findReplaceZext(vector<PieceNode> &stack,Datatype *structuredType,Funcdata &data)
+
+{
+  bool change = false;
+  for(int4 i=0;i<stack.size();++i) {
+    PieceNode &node(stack[i]);
+    if (!node.isLeaf()) continue;
+    Varnode *vn = node.getVarnode();
+    if (!vn->isWritten()) continue;
+    PcodeOp *op = vn->getDef();
+    if (op->code() != CPUI_INT_ZEXT) continue;
+    if (!spanningRange(structuredType,node.getTypeOffset(),vn->getSize())) continue;
+    if (convertZextToPiece(op,structuredType,node.getTypeOffset(),data))
+      change = true;
+  }
+  return change;
+}
+
+/// \brief Return \b true if the two given \b root and \b leaf should be part of different symbols
+///
+/// A leaf in a CONCAT tree can be in a separate from the root if it is a parameter or a separate root.
+/// \param root is the root of the CONCAT tree
+/// \param leaf is the given leaf Varnode
+/// \return \b true if the two Varnodes should be in different symbols
+bool RulePieceStructure::separateSymbol(Varnode *root,Varnode *leaf)
+
+{
+  if (root->getSymbolEntry() != leaf->getSymbolEntry()) return true;	// Forced to be different symbols
+  if (root->isAddrTied()) return false;
+  if (!leaf->isWritten()) return true;	// Assume to be different symbols
+  if (leaf->isProtoPartial()) return true;	// Already in another tree
+  PcodeOp *op = leaf->getDef();
+  if (op->code() != CPUI_PIECE) return false;
+  if (leaf->getType()->isPieceStructured()) return true;	// Would be a separate root
+
+  return false;
+}
+
+/// \class RulePieceStructure
+/// \brief Concatenating structure pieces gets printed as explicit write statements
+///
+/// Set properties so that a CONCAT expression like `v = CONCAT(CONCAT(v1,v2),CONCAT(v3,v4))` gets
+/// rendered as a sequence of separate write statements. `v.field1 = v1; v.field2 = v2; v.field3 = v3; v.field4 = v4;`
+void RulePieceStructure::getOpList(vector<uint4> &oplist) const
+
+{
+  oplist.push_back(CPUI_PIECE);
+  oplist.push_back(CPUI_INT_ZEXT);
+}
+
+int4 RulePieceStructure::applyOp(PcodeOp *op,Funcdata &data)
+
+{
+  if (op->isPartialRoot()) return 0;		// Check if CONCAT tree already been visited
+  Varnode *outvn = op->getOut();
+  int4 baseOffset;
+  Datatype *ct = determineDatatype(outvn, baseOffset);
+  if (ct == (Datatype *)0) return 0;
+
+  if (op->code() == CPUI_INT_ZEXT) {
+    if (convertZextToPiece(op,outvn->getType(),0,data))
+      return 1;
+    return 0;
+  }
+  // Check if outvn is really the root of the tree
+  PcodeOp *zext = outvn->loneDescend();
+  if (zext != (PcodeOp*)0) {
+    if (zext->code() == CPUI_PIECE)
+      return 0;		// More PIECEs below us, not a root
+    if (zext->code() == CPUI_INT_ZEXT) {
+      // Extension of a structured data-type,  convert extension to PIECE first
+      if (convertZextToPiece(zext,zext->getOut()->getType(),0,data))
+	return 1;
+      return 0;
+    }
+  }
+
+  vector<PieceNode> stack;
+  for(;;) {
+    PieceNode::gatherPieces(stack, outvn, op, baseOffset);
+    if (!findReplaceZext(stack, ct, data))	// Check for INT_ZEXT leaves that need to be converted to PIECEs
+      break;
+    stack.clear();	// If we found some, regenerate the tree
+  }
+
+  op->setPartialRoot();
+  bool anyAddrTied = outvn->isAddrTied();
+  Address baseAddr = outvn->getAddr() - baseOffset;
+  for(int4 i=0;i<stack.size();++i) {
+    PieceNode &node(stack[i]);
+    Varnode *vn = node.getVarnode();
+    Address addr = baseAddr + node.getTypeOffset();
+    if (vn->getAddr() == addr) {
+      if (!node.isLeaf() || !separateSymbol(outvn, vn)) {
+	// Varnode already has correct address and will be part of the same symbol as root
+	// so we don't need to change the storage or insert a COPY
+	if (!vn->isAddrTied() && !vn->isProtoPartial()) {
+	  vn->setProtoPartial();
+	}
+	anyAddrTied = anyAddrTied || vn->isAddrTied();
+	continue;
+      }
+    }
+    if (node.isLeaf()) {
+      PcodeOp *copyOp = data.newOp(1,node.getOp()->getAddr());
+      Varnode *newVn = data.newVarnodeOut(vn->getSize(), addr, copyOp);
+      anyAddrTied = anyAddrTied || newVn->isAddrTied();	// Its possible newVn is addrtied, even if vn isn't
+      Datatype *newType = data.getArch()->types->getExactPiece(ct, node.getTypeOffset(), vn->getSize());
+      if (newType == (Datatype *)0)
+	newType = vn->getType();
+      newVn->updateType(newType, false, false);
+      data.opSetOpcode(copyOp, CPUI_COPY);
+      data.opSetInput(copyOp, vn, 0);
+      data.opSetInput(node.getOp(),newVn,node.getSlot());
+      data.opInsertBefore(copyOp, node.getOp());
+      if (vn->getType()->needsResolution()) {
+	// Inherit PIECE's read resolution for COPY's read
+	data.inheritResolution(vn->getType(), copyOp, 0, node.getOp(), node.getSlot());
+      }
+      if (newType->needsResolution()) {
+	newType->resolveInFlow(copyOp, -1);	// If the piece represents part of a union, resolve it
+      }
+      if (!newVn->isAddrTied())
+	newVn->setProtoPartial();
+    }
+    else {
+      // Reaching here we know vn is NOT addrtied and has a lone descendant
+      // We completely replace the Varnode with one having the correct storage
+      PcodeOp *defOp = vn->getDef();
+      PcodeOp *loneOp = vn->loneDescend();
+      int4 slot = loneOp->getSlot(vn);
+      Varnode *newVn = data.newVarnode(vn->getSize(), addr, vn->getType());
+      data.opSetOutput(defOp, newVn);
+      data.opSetInput(loneOp, newVn, slot);
+      data.deleteVarnode(vn);
+      if (!newVn->isAddrTied())
+	newVn->setProtoPartial();
+    }
+  }
+  if (!anyAddrTied)
+    data.getMerge().registerProtoPartialRoot(outvn);
+  return 1;
+}
+
 /// \class RuleSubNormal
 /// \brief Pull-back SUBPIECE through INT_RIGHT and INT_SRIGHT
 ///
@@ -8142,7 +8301,7 @@ Varnode *RuleSignMod2nOpt2::checkSignExtForm(PcodeOp *op)
 /// \brief Verify an \e if block like `V = (V s< 0) ? V + 2^n-1 : V`
 ///
 /// \param op is the MULTIEQUAL
-/// \param npos is the constant 2^n
+/// \param npow is the constant 2^n
 /// \return the Varnode V in the form, or null if the form doesn't match
 Varnode *RuleSignMod2nOpt2::checkMultiequalForm(PcodeOp *op,uintb npow)
 

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

@@ -940,16 +940,6 @@ public:
   virtual void getOpList(vector<uint4> &oplist) const;
   virtual int4 applyOp(PcodeOp *op,Funcdata &data);
 };
-class RuleEmbed : public Rule {
-public:
-  RuleEmbed(const string &g) : Rule(g, 0, "embed") {}	///< Constructor
-  virtual Rule *clone(const ActionGroupList &grouplist) const {
-    if (!grouplist.contains(getGroup())) return (Rule *)0;
-    return new RuleEmbed(getGroup());
-  }
-  virtual void getOpList(vector<uint4> &oplist) const;
-  virtual int4 applyOp(PcodeOp *op,Funcdata &data);
-};
 class RuleSwitchSingle : public Rule {
 public:
   RuleSwitchSingle(const string &g) : Rule(g,0,"switchsingle") {}	///< Constructor
@@ -1155,6 +1145,23 @@ public:
   virtual int4 applyOp(PcodeOp *op,Funcdata &data);
 };
 
+class RulePieceStructure : public Rule {
+  /// \brief Markup for Varnodes pieced together into structure/array
+  static Datatype *determineDatatype(Varnode *vn,int4 &baseOffset);
+  static bool spanningRange(Datatype *ct,int4 off,int4 size);
+  static bool convertZextToPiece(PcodeOp *zext,Datatype *structuredType,int4 offset,Funcdata &data);
+  static bool findReplaceZext(vector<PieceNode> &stack,Datatype *structuredType,Funcdata &data);
+  static bool separateSymbol(Varnode *root,Varnode *leaf);
+public:
+  RulePieceStructure(const string &g) : Rule( g, 0, "piecestructure") {}	///< Constructor
+  virtual Rule *clone(const ActionGroupList &grouplist) const {
+    if (!grouplist.contains(getGroup())) return (Rule *)0;
+    return new RulePieceStructure(getGroup());
+  }
+  virtual void getOpList(vector<uint4> &oplist) const;
+  virtual int4 applyOp(PcodeOp *op,Funcdata &data);
+};
+
 class RuleSubNormal : public Rule {
 public:
   RuleSubNormal(const string &g) : Rule( g, 0, "subnormal") {}	///< Constructor

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

@@ -1924,13 +1924,13 @@ const TypeField *TypePartialUnion::findTruncation(int4 off,int4 sz,const PcodeOp
   return container->findTruncation(off + offset, sz, op, slot, newoff);
 }
 
-int4 TypePartialUnion::numDepend(void)
+int4 TypePartialUnion::numDepend(void) const
 
 {
   return container->numDepend();
 }
 
-Datatype *TypePartialUnion::getDepend(int4 index)
+Datatype *TypePartialUnion::getDepend(int4 index) const
 
 {
   // Treat dependents as coming from the underlying union
@@ -3483,6 +3483,31 @@ TypePointer *TypeFactory::getTypePointerWithSpace(Datatype *ptrTo,AddrSpace *spc
   return res;
 }
 
+/// Drill down into nested data-types until we get to a data-type that exactly matches the
+/// given offset and size, and return this data-type.  Any \e union data-type encountered
+/// terminates the process and a partial union data-type is constructed and returned.
+/// If the range indicated by the offset and size contains only a partial field or crosses
+/// field boundaries, null is returned.
+/// \param ct is the structured data-type
+/// \param offset is the starting byte offset for the piece
+/// \param size is the number of bytes in the piece
+/// \return the data-type of the piece or null
+Datatype *TypeFactory::getExactPiece(Datatype *ct,int4 offset,int4 size)
+
+{
+  uintb newOff = offset;
+  while(ct != (Datatype *)0 && ct->getSize() > size && ct->getMetatype() != TYPE_UNION) {
+    ct = ct->getSubType(newOff, &newOff);
+  }
+  if (ct == (Datatype *)0 || ct->getSize() < size)
+    return (Datatype *)0;
+  if (ct->getSize() == size)
+    return ct;
+  if (ct->getMetatype() == TYPE_UNION)	// If we hit a containing union
+    return getTypePartialUnion((TypeUnion *)ct, newOff, size);
+  return (Datatype *)0;
+}
+
 /// The indicated Datatype object is removed from this container.
 /// Indirect references (via TypeArray TypeStruct etc.) are not affected
 /// \param ct is the data-type to destroy

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

@@ -222,6 +222,7 @@ public:
   int4 typeOrder(const Datatype &op) const { if (this==&op) return 0; return compare(op,10); }	///< Order this with -op- datatype
   int4 typeOrderBool(const Datatype &op) const;	///< Order \b this with -op-, treating \e bool data-type as special
   void encodeRef(Encoder &encoder) const;	///< Encode a reference of \b this to a stream
+  bool isPieceStructured(void) const;		///< Does \b this data-type consist of separate pieces?
   static uint4 encodeIntegerFormat(const string &val);
   static string decodeIntegerFormat(uint4 val);
 };
@@ -501,8 +502,8 @@ public:
   TypeUnion *getParentUnion(void) const { return container; }	///< Get the union which \b this is part of
   virtual void printRaw(ostream &s) const;			///< Print a description of the type to stream
   virtual const TypeField *findTruncation(int4 off,int4 sz,const PcodeOp *op,int4 slot,int4 &newoff) const;
-  virtual int4 numDepend(void);
+  virtual int4 numDepend(void) const;
-  virtual Datatype *getDepend(int4 index);
+  virtual Datatype *getDepend(int4 index) const;
   virtual int4 compare(const Datatype &op,int4 level) const;
   virtual int4 compareDependency(const Datatype &op) const;
   virtual Datatype *clone(void) const { return new TypePartialUnion(*this); }
@@ -691,6 +692,7 @@ public:
   TypePointerRel *getTypePointerRel(TypePointer *parentPtr,Datatype *ptrTo,int4 off);	///< Get pointer offset relative to a container
   TypePointerRel *getTypePointerRel(int4 sz,Datatype *parent,Datatype *ptrTo,int4 ws,int4 off,const string &nm);
   TypePointer *getTypePointerWithSpace(Datatype *ptrTo,AddrSpace *spc,const string &nm);
+  Datatype *getExactPiece(Datatype *ct,int4 offset,int4 size);	///< Get the data-type associated with piece of a structured data-type
   void destroyType(Datatype *ct);				///< Remove a data-type from \b this
   Datatype *concretize(Datatype *ct);				///< Convert given data-type to concrete form
   void dependentOrder(vector<Datatype *> &deporder) const;	///< Place all data-types in dependency order
@@ -745,6 +747,18 @@ inline int4 Datatype::typeOrderBool(const Datatype &op) const
   return compare(op,10);
 }
 
+/// If a value with \b this data-type is put together from multiple pieces, is it better to display
+/// this construction as a sequence of separate assignments or as a single concatenation.
+/// Generally a TYPE_STRUCT or TYPE_ARRAY should be represented with separate assignments.
+/// \return \b true if the data-type is put together with multiple assignments
+inline bool Datatype::isPieceStructured(void) const
+
+{
+//  if (metatype == TYPE_STRUCT || metatype == TYPE_ARRAY || metatype == TYPE_UNION ||
+//      metatype == TYPE_PARTIALUNION || metatype == TYPE_PARTIALSTRUCT)
+  return (metatype <= TYPE_ARRAY);
+}
+
 inline TypeArray::TypeArray(int4 n,Datatype *ao) : Datatype(n*ao->getSize(),TYPE_ARRAY)
 
 {

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

@@ -1929,18 +1929,20 @@ string TypeOpSubpiece::getOperatorName(const PcodeOp *op) const
 Datatype *TypeOpSubpiece::getOutputToken(const PcodeOp *op,CastStrategy *castStrategy) const
 
 {
+  const Varnode *outvn = op->getOut();
+  const TypeField *field;
+  Datatype *ct = op->getIn(0)->getHighTypeReadFacing(op);
   int4 offset;
-  Datatype *parent;
+  int4 byteOff = computeByteOffsetForComposite(op);
-  const Varnode *vn = op->getOut();
+ field = ct->findTruncation(byteOff,outvn->getSize(),op,1,offset);	// Use artificial slot
-  const TypeField *field = testExtraction(true, op, parent, offset);
   if (field != (const TypeField *)0) {
-    if (vn->getSize() == field->type->getSize())
+    if (outvn->getSize() == field->type->getSize())
       return field->type;
   }
-  Datatype *dt = vn->getHighTypeDefFacing();	// SUBPIECE prints as cast to whatever its output is
+  Datatype *dt = outvn->getHighTypeDefFacing();	// SUBPIECE prints as cast to whatever its output is
   if (dt->getMetatype() != TYPE_UNKNOWN)
     return dt;
-  return tlst->getBase(vn->getSize(),TYPE_INT);	// If output is unknown, treat as cast to int
+  return tlst->getBase(outvn->getSize(),TYPE_INT);	// If output is unknown, treat as cast to int
 }
 
 Datatype *TypeOpSubpiece::propagateType(Datatype *alttype,PcodeOp *op,Varnode *invn,Varnode *outvn,
@@ -1969,30 +1971,6 @@ Datatype *TypeOpSubpiece::propagateType(Datatype *alttype,PcodeOp *op,Varnode *i
   return (Datatype *)0;
 }
 
-/// \brief Test if the given SUBPIECE PcodeOp is acting as a field extraction operator
-///
-/// For packed structures with small fields,  SUBPIECE may be used to extract the field.
-/// Test if the HighVariable being truncated is a structure and if the truncation produces
-/// part of a \e single field.  If so return the TypeField descriptor, and pass back the parent
-/// structure and the number of least significant bytes that have been truncated from the field.
-/// \param useHigh is \b true if the HighVariable data-type is checked, otherwise the Varnode data-type is used
-/// \param op is the given SUBPIECE PcodeOp
-/// \param parent holds the parent Datatype being passed back
-/// \param offset holds the LSB offset being passed back
-/// \return the TypeField if a field is being extracted or null otherwise
-const TypeField *TypeOpSubpiece::testExtraction(bool useHigh,const PcodeOp *op,Datatype *&parent,int4 &offset)
-
-{
-  const Varnode *vn = op->getIn(0);
-  Datatype *ct = useHigh ? vn->getHighTypeReadFacing(op) : vn->getTypeReadFacing(op);
-  type_metatype meta = ct->getMetatype();
-  if (meta != TYPE_STRUCT && meta != TYPE_UNION && meta != TYPE_PARTIALUNION)
-    return (const TypeField *)0;
-  parent = ct;
-  int4 byteOff = computeByteOffsetForComposite(op);
-  return ct->findTruncation(byteOff,op->getOut()->getSize(),op,1,offset);	// Use artificial slot
-}
-
 /// \brief Compute the byte offset into an assumed composite data-type produced by the given CPUI_SUBPIECE
 ///
 /// If the input Varnode is a composite data-type, the extracted result of the SUBPIECE represent a

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

@@ -749,7 +749,6 @@ public:
 				  int4 inslot,int4 outslot);
   virtual string getOperatorName(const PcodeOp *op) const;
   virtual void push(PrintLanguage *lng,const PcodeOp *op,const PcodeOp *readOp) const { lng->opSubpiece(op); }
-  static const TypeField *testExtraction(bool useHigh,const PcodeOp *op,Datatype *&parent,int4 &offset);
   static int4 computeByteOffsetForComposite(const PcodeOp *op);
 };
 

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

@@ -44,6 +44,7 @@ extern ElementId ELEM_SEGMENTOP;	///< Marshaling element \<segmentop>
 /// its CALLOTHER index.  A facility for reading in implementation details is provided via decode().
 class UserPcodeOp {
 public:
+  /// \brief Enumeration of different boolean properties that can be assigned to a CALLOTHER
   enum userop_flags {
     annotation_assignment = 1,	///< Displayed as assignment, `in1 = in2`, where the first parameter is an annotation
     no_operator = 2		///< Don't emit special token, just emit the first input parameter as expression

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

@@ -24,8 +24,9 @@ AttributeId ATTRIB_SYMREF = AttributeId("symref",68);
 ElementId ELEM_HIGH = ElementId("high",82);
 
 /// Compare by offset within the group, then by size.
-/// \param op2 is the other piece to compare with \b this
+/// \param a is the first piece to compare
-/// \return \b true if \b this should be ordered before the other piece
+/// \param b is the other piece to compare
+/// \return \b true if \b a should be ordered before the \b b
 bool VariableGroup::PieceCompareByOffset::operator()(const VariablePiece *a,const VariablePiece *b) const
 
 {
@@ -145,7 +146,7 @@ void VariablePiece::adjustOffset(int4 amt)
 }
 
 /// If there are no remaining references to the old VariableGroup it is deleted.
-/// \param newGropu is the new VariableGroup to transfer \b this to
+/// \param newGroup is the new VariableGroup to transfer \b this to
 void VariablePiece::transferGroup(VariableGroup *newGroup)
 
 {
@@ -227,15 +228,26 @@ void HighVariable::setSymbol(Varnode *vn) const
     }
   }
   symbol = entry->getSymbol();
-  if (entry->isDynamic())	// Dynamic symbols match whole variable
+  if (vn->isProtoPartial()) {
+    Varnode *rootVn = PieceNode::findRoot(vn);
+    if (rootVn == vn)
+      throw LowlevelError("Partial varnode does not match symbol");
+
+    symboloffset = vn->getAddr().overlap(0,rootVn->getAddr(),rootVn->getSize());
+    SymbolEntry *entry = rootVn->getSymbolEntry();
+    if (entry != (SymbolEntry *)0)
+      symboloffset += entry->getOffset();
+  }
+  else if (entry->isDynamic())	// Dynamic symbols (that aren't partials) match whole variable
     symboloffset = -1;
   else if (symbol->getCategory() == Symbol::equate)
     symboloffset = -1;			// For equates, we don't care about size
   else if (symbol->getType()->getSize() == vn->getSize() &&
       entry->getAddr() == vn->getAddr() && !entry->isPiece())
     symboloffset = -1;			// A matching entry
-  else
+  else {
     symboloffset = vn->getAddr().overlap(0,entry->getAddr(),symbol->getType()->getSize()) + entry->getOffset();
+  }
 
   highflags &= ~((uint4)symboldirty);		// We are no longer dirty
 }
@@ -455,6 +467,21 @@ Varnode *HighVariable::getNameRepresentative(void) const
   return nameRepresentative;
 }
 
+/// Find the first member that is either address tied or marked as a proto partial.
+/// \return a member Varnode acting as partial storage or null if none exist
+Varnode *HighVariable::getPartial(void) const
+
+{
+  int4 i;
+
+  for(i=0;i<inst.size();++i) {
+    Varnode *vn = inst[i];
+    if (vn->isAddrTied() || vn->isProtoPartial())
+      return vn;
+  }
+  return (Varnode *)0;
+}
+
 /// Search for the given Varnode and cut it out of the list, marking all properties as \e dirty.
 /// \param vn is the given Varnode member to remove
 void HighVariable::remove(Varnode *vn)
@@ -726,6 +753,15 @@ int4 HighVariable::instanceIndex(const Varnode *vn) const
   return -1;
 }
 
+/// \param op2 is the other HighVariable to compare with \b this
+/// \return \b true if they are in the same group
+bool HighVariable::sameGroup(const HighVariable *op2) const
+
+{
+  if (piece == (VariablePiece *)0 || op2->piece == (VariablePiece *)0) return false;
+  return (piece->getGroup() == op2->piece->getGroup());
+}
+
 /// \param encoder is the stream encoder
 void HighVariable::encode(Encoder &encoder) const
 

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

@@ -179,6 +179,7 @@ public:
   Varnode *getInputVarnode(void) const;		///< Find (the) input member Varnode
   Varnode *getTypeRepresentative(void) const;	///< Get a member Varnode with the strongest data-type
   Varnode *getNameRepresentative(void) const;	///< Get a member Varnode that dictates the naming of \b this HighVariable
+  Varnode *getPartial(void) const;		///< Find the first member that can act as partial symbol storage
   int4 getNumMergeClasses(void) const { return numMergeClasses; }	///< Get the number of speculative merges for \b this
   bool isMapped(void) const { updateFlags(); return ((flags&Varnode::mapped)!=0); }	///< Return \b true if \b this is mapped
   bool isPersist(void) const { updateFlags(); return ((flags&Varnode::persist)!=0); }	///< Return \b true if \b this is a global variable
@@ -189,6 +190,7 @@ public:
   bool isConstant(void) const { updateFlags(); return ((flags&Varnode::constant)!=0); }	///< Return \b true if \b this is a constant
   bool isUnaffected(void) const { updateFlags(); return ((flags&Varnode::unaffected)!=0); }	///< Return \b true if \b this is an \e unaffected register
   bool isExtraOut(void) const { updateFlags(); return ((flags&(Varnode::indirect_creation|Varnode::addrtied))==Varnode::indirect_creation); }	///< Return \b true if \b this is an extra output
+  bool isPartial(void) const { updateFlags(); return ((flags&(Varnode::addrtied|Varnode::proto_partial))!=0); }	///< Return \b true if \b this is potential partial symbol
   void setMark(void) const { flags |= Varnode::mark; }		///< Set the mark on this variable
   void clearMark(void) const { flags &= ~Varnode::mark; }	///< Clear the mark on this variable
   bool isMark(void) const { return ((flags&Varnode::mark)!=0); }	///< Return \b true if \b this is marked
@@ -205,6 +207,7 @@ public:
   bool isUnattached(void) const { return inst.empty(); }	///< Return \b true if \b this has no member Varnode
   bool isTypeLock(void) const { updateType(); return ((flags & Varnode::typelock)!=0); }	///< Return \b true if \b this is \e typelocked
   bool isNameLock(void) const { updateFlags(); return ((flags & Varnode::namelock)!=0); }	///< Return \b true if \b this is \e namelocked
+  bool sameGroup(const HighVariable *op2) const;	///< Return \b true if \b and other variable are parts of the same variable
   void encode(Encoder &encoder) const;		///< Encode \b this variable to stream as a \<high> element
 #ifdef MERGEMULTI_DEBUG
   void verifyCover(void) const;

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

@@ -936,6 +936,13 @@ bool Varnode::findSubpieceShadow(int4 leastByte,const Varnode *whole,int4 recurs
   return false;
 }
 
+/// \brief Try to find a PIECE operation that produces \b this from a given Varnode \b piece
+///
+/// \param leastByte is the number of least significant bytes being truncated from the
+/// putative \b this to get \b piece.  The routine can backtrack through COPY operations and
+/// more than one PIECE operations to verify that \b this is formed out of \b piece.
+/// \param piece is the given Varnode piece
+/// \return \b true if \b this and \b whole have the prescribed PIECE relationship
 bool Varnode::findPieceShadow(int4 leastByte,const Varnode *piece) const
 
 {
@@ -1007,6 +1014,23 @@ bool Varnode::partialCopyShadow(const Varnode *op2,int4 relOff) const
   return false;
 }
 
+/// If \b this has a data-type built out of separate pieces, return it.
+/// If \b this is mapped as a partial to a symbol with one of these data-types, return it.
+/// Return null otherwise.
+/// \return the associated structured data-type or null
+Datatype *Varnode::getStructuredType(void) const
+
+{
+  Datatype *ct;
+  if (mapentry != (SymbolEntry *)0)
+    ct = mapentry->getSymbol()->getType();
+  else
+    ct = type;
+  if (ct->isPieceStructured())
+    return ct;
+  return (Datatype *)0;
+}
+
 /// Compare term order of two Varnodes. Used in Term Rewriting strategies to order operands of commutative ops
 /// \param op is the Varnode to order against \b this
 /// \return -1 if \b this comes before \b op, 1 if op before this, or 0

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

@@ -109,7 +109,8 @@ public:
     indirectstorage = 0x8000000, ///< Is this Varnode storing a pointer to the actual symbol
     hiddenretparm = 0x10000000,	 ///< Does this varnode point to the return value storage location
     incidental_copy = 0x20000000, ///< Do copies of this varnode happen as a side-effect
-    autolive_hold = 0x40000000	///< Temporarily block dead-code removal of \b this
+    autolive_hold = 0x40000000,	///< Temporarily block dead-code removal of \b this
+    proto_partial = 0x80000000	///< Varnode is getting PIECEd together into an (unmapped) structure
   };
   /// Additional boolean properties on a Varnode
   enum addl_flags {
@@ -250,6 +251,7 @@ public:
   bool isUnaffected(void) const { return ((flags&Varnode::unaffected)!=0); } ///< Is \b this a value that is supposed to be preserved across the function?
   bool isSpacebase(void) const { return ((flags&Varnode::spacebase)!=0); } ///< Is this location used to store the base point for a virtual address space?
   bool isReturnAddress(void) const { return ((flags&Varnode::return_address)!=0); } ///< Is this storage for a calls return address?
+  bool isProtoPartial(void) const { return ((flags&Varnode::proto_partial)!=0); } ///< Is \b this getting pieced together into a larger whole
   bool isPtrCheck(void) const { return ((addlflags&Varnode::ptrcheck)!=0); } ///< Has \b this been checked as a constant pointer to a mapped symbol?
   bool isPtrFlow(void) const { return ((addlflags&Varnode::ptrflow)!=0); } ///< Does this varnode flow to or from a known pointer
   bool isSpacebasePlaceholder(void) const { return ((addlflags&Varnode::spacebase_placeholder)!=0); } ///< Is \b this used specifically to track stackpointer values?
@@ -318,6 +320,8 @@ public:
   void clearWriteMask(void) { addlflags &= ~Varnode::writemask; } ///< Clear the mark indicating \b this is not a true write
   void setAutoLiveHold(void) { flags |= Varnode::autolive_hold; }	///< Place temporary hold on dead code removal
   void clearAutoLiveHold(void) { flags &= ~Varnode::autolive_hold; }	///< Clear temporary hold on dead code removal
+  void setProtoPartial(void) { flags |= Varnode::proto_partial; }	///< Mark \b this gets pieced into larger structure
+  void clearProtoPartial(void) { flags &= ~Varnode::proto_partial; }	///< Clear mark indicating \b this gets pieced into larger structure
   void setUnsignedPrint(void) { addlflags |= Varnode::unsignedprint; } ///< Force \b this to be printed as unsigned
   void setLongPrint(void) { addlflags |= Varnode::longprint; }	///< Force \b this to be printed as a \e long token
   void setStopUpPropagation(void) { addlflags |= Varnode::stop_uppropagation; }	///< Stop up-propagation thru \b this
@@ -334,6 +338,7 @@ public:
   bool findSubpieceShadow(int4 leastByte,const Varnode *whole,int4 recurse) const;
   bool findPieceShadow(int4 leastByte,const Varnode *piece) const;
   bool partialCopyShadow(const Varnode *op2,int4 relOff) const;	///< Is one of \b this or \b op2 a partial copy of the other?
+  Datatype *getStructuredType(void) const;	///< Get structure/array/union that \b this is a piece of
   void encode(Encoder &encoder) const; ///< Encode a description of \b this to a stream
   static bool comparePointers(const Varnode *a,const Varnode *b) { return (*a < *b); }	///< Compare Varnodes as pointers
   static void printRaw(ostream &s,const Varnode *vn);	///< Print raw info about a Varnode to stream

Ghidra/Features/Decompiler/src/decompile/datatests/concat.xml

@@ -0,0 +1,81 @@
+<decompilertest>
+<binaryimage arch="x86:LE:64:default:gcc">
+<!--
+    Examples of entire structures built out of PIECE and ZEXT operations.
+    We should see the individual fields being read/assigned and not CONCAT or ZEXT inlines.
+-->
+<bytechunk space="ram" offset="0x100783" readonly="true">
+      4883ec0889f84889f748c1e720
+4809c7e812ffffff4883c408c348c1e6
+2089f84809f0c30fb7c648c1e0104889
+c60fb7c70fb7d248c1e2204809f048c1
+e1304809d04809c8c35389f366893d4f
+082000488b3d46082000e806ffffff66
+891d400820005bc389f8c3
+</bytechunk>
+<bytechunk space="ram" offset="0x100847" readonly="true">
+              554889e5897dec8b45
+ec8945f8c745fc00000000488b45f85d
+c3
+</bytechunk>
+<symbol space="ram" offset="0x1006aa" name="structparam"/>
+<symbol space="ram" offset="0x1006e5" name="structshort"/>
+<symbol space="ram" offset="0x100783" name="concatregparam"/>
+<symbol space="ram" offset="0x10079d" name="concatreturn"/>
+<symbol space="ram" offset="0x1007a7" name="concatreturnshort"/>
+<symbol space="ram" offset="0x1007c9" name="replaceshort"/>
+<symbol space="ram" offset="0x1007e8" name="zerofield"/>
+<symbol space="ram" offset="0x100847" name="zerofield2"/>
+</binaryimage>
+<script>
+  <com>parse line struct foo { int4 A; int4 B; };</com>
+  <com>parse line struct fooshort { int2 a; int2 b; int2 c; int2 d; };</com>
+  <com>map addr r0x301020 fooshort globshort</com>
+  <com>parse line extern void structparam(foo param_1);</com>
+  <com>parse line extern void structshort(fooshort param_1);</com>
+  <com>parse line extern void concatregparam(int4 regp1,int4 regp2);</com>
+  <com>parse line extern foo concatreturn(int4 retp1,int4 retp2);</com>
+  <com>parse line extern fooshort concatreturnshort(int2 short1,int2 short2,int2 short3,int2 short4);</com>
+  <com>parse line extern void replaceshort(int2 replace1,int2 replace2);</com>
+  <com>parse line extern foo zerofield(int4 zero1);</com>
+  <com>parse line extern foo zerofield2(int4 zero_two1);</com>
+  <com>lo fu concatregparam</com>
+  <com>decompile</com>
+  <com>print C</com>
+  <com>lo fu concatreturn</com>
+  <com>decompile</com>
+  <com>print C</com>
+  <com>lo fu concatreturnshort</com>
+  <com>decompile</com>
+  <com>print C</com>
+  <com>lo fu replaceshort</com>
+  <com>decompile</com>
+  <com>print C</com>
+  <com>lo fu zerofield</com>
+  <com>decompile</com>
+  <com>print C</com>
+  <com>lo fu zerofield2</com>
+  <com>map hash r0x10085b 7df6374cc45 foo footwo</com>
+  <com>decompile</com>
+  <com>print C</com>
+  <com>quit</com>
+</script>
+<stringmatch name="Concat #1" min="0" max="0">CONCAT</stringmatch>
+<stringmatch name="Concat #2" min="0" max="0">ZEXT</stringmatch>
+<stringmatch name="Concat #3" min="1" max="1">fVar1\.A = regp1;</stringmatch>
+<stringmatch name="Concat #4" min="1" max="1">fVar1\.B = regp2;</stringmatch>
+<stringmatch name="Concat #5" min="1" max="1">fVar1\.A = retp1;</stringmatch>
+<stringmatch name="Concat #6" min="1" max="1">fVar1\.B = retp2;</stringmatch>
+<stringmatch name="Concat #7" min="1" max="1">fVar1\.a = short1;</stringmatch>
+<stringmatch name="Concat #8" min="1" max="1">fVar1\.b = short2;</stringmatch>
+<stringmatch name="Concat #9" min="1" max="1">fVar1\.c = short3;</stringmatch>
+<stringmatch name="Concat #10" min="1" max="1">fVar1\.d = short4;</stringmatch>
+<stringmatch name="Concat #11" min="1" max="1">globshort\.b = replace1;</stringmatch>
+<stringmatch name="Concat #12" min="1" max="1">globshort\.d = replace2;</stringmatch>
+<stringmatch name="Concat #13" min="0" max="0">globshort\.a =</stringmatch>
+<stringmatch name="Concat #14" min="0" max="0">globshort\.c =</stringmatch>
+<stringmatch name="Concat #15" min="1" max="1">fVar1\.A = zero1;</stringmatch>
+<stringmatch name="Concat #16" min="1" max="1">fVar1\.B = 0;</stringmatch>
+<stringmatch name="Concat #17" min="1" max="1">footwo\.A = zero_two1;</stringmatch>
+<stringmatch name="Concat #18" min="1" max="1">footwo\.B = 0;</stringmatch>
+</decompilertest>

Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/program/model/pcode/HighSymbol.java

@@ -166,15 +166,23 @@ public class HighSymbol {
 	/**
 	 * Associate a particular HighVariable with this symbol. This is used to link the symbol
 	 * into the decompiler's description of how a function manipulates a particular symbol.
+	 * Multiple partial HighVariables may get associated with the same HighSymbol.  The HighSymbol
+	 * keeps a reference to the biggest HighVariable passed to this method.
 	 * @param high is the associated HighVariable
 	 */
-	public void setHighVariable(HighVariable high) {
+	void setHighVariable(HighVariable high) {
-		this.highVariable = high;
+		if (highVariable != null) {
+			if (highVariable.getSize() >= high.getSize()) {
+				return;
+			}
+		}
+		highVariable = high;
 	}
 
 	/**
-	 * Get the HighVariable associate with this symbol if any.  This allows the user to go straight
+	 * Get the HighVariable associate with this symbol if any.  The symbol may have multiple
-	 * into the decompiler's function to see how the symbol gets manipulated.
+	 * partial HighVariables associated with it. This method returns the biggest one, which
+	 * may not be the same size as the symbol itself.
 	 * @return the associated HighVariable or null
 	 */
 	public HighVariable getHighVariable() {