rearrange LoadGuard class

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

@@ -232,6 +232,8 @@ public:
   /// \return \b true if the Varnode is fully linked
   bool isHeritaged(Varnode *vn) { return (heritage.heritagePass(vn->getAddr())>=0); }
 
+  const list<LoadGuard> &getLoadGuards(void) const { return heritage.getLoadGuards(); }
+
   // Function prototype and call specification routines
   int4 numCalls(void) const { return qlst.size(); }	///< Get the number of calls made by \b this function
   FuncCallSpecs *getCallSpecs(int4 i) const { return qlst[i]; }	///< Get the i-th call specification

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

@@ -578,22 +578,20 @@ void Heritage::handleNewLoadCopies(void)
 ///
 /// isAnalyzed is set to \b true, if full range analysis is not needed
 /// \param valueSet is the calculated value set as seen by the LOAD operation
-void Heritage::LoadGuard::establishRange(const ValueSetRead &valueSet)
+void LoadGuard::establishRange(const ValueSetRead &valueSet)
 
 {
   const CircleRange &range( valueSet.getRange() );
   uintb rangeSize = range.getSize();
   uintb size;
   if (range.isEmpty()) {
-    step = 0;
     minimumOffset = pointerBase;
     size = 0x1000;
   }
   else if (range.isFull() || rangeSize > 0xffffff) {
-    step = 1;
     minimumOffset = pointerBase;
     size = 0x1000;
-    isAnalyzed = true;	// Don't bother doing more analysis
+    analysisState = 1;	// Don't bother doing more analysis
   }
   else {
     step = (rangeSize == 3) ? range.getStep() : 0;	// Check for consistent step
@@ -627,21 +625,20 @@ void Heritage::LoadGuard::establishRange(const ValueSetRead &valueSet)
   }
 }
 
-void Heritage::LoadGuard::finalizeRange(const ValueSetRead &valueSet)
+void LoadGuard::finalizeRange(const ValueSetRead &valueSet)
 
 {
-  isAnalyzed = true;		// In all cases the settings determined here are final
+  analysisState = 1;		// In all cases the settings determined here are final
   const CircleRange &range( valueSet.getRange() );
   uintb rangeSize = range.getSize();
   if (rangeSize > 1 && rangeSize < 0xffffff) {	// Did we converge to something reasonable
+    analysisState = 2;			// Mark that we got a definitive result
     step = range.getStep();
     minimumOffset = range.getMin();
     maximumOffset = range.getMax();
     if (maximumOffset < minimumOffset)	// Values extend into what is usually stack parameters
       maximumOffset = spc->getHighest();
   }
-  if (step == 0)
-    step = 1;
   if (minimumOffset > spc->getHighest())
     minimumOffset = spc->getHighest();
   if (maximumOffset > spc->getHighest())
@@ -652,14 +649,14 @@ void Heritage::analyzeNewLoadGuards(void)
 
 {
   if (loadGuard.empty()) return;
-  if (loadGuard.back().isAnalyzed) return;	// Nothing new
+  if (loadGuard.back().analysisState != 0) return;	// Nothing new
   list<LoadGuard>::iterator startIter = loadGuard.end();
   vector<Varnode *> sinks;
   vector<PcodeOp *> reads;
   while(startIter != loadGuard.begin()) {
     --startIter;
     LoadGuard &guard( *startIter );
-    if (guard.isAnalyzed) break;
+    if (guard.analysisState != 0) break;
     reads.push_back(guard.op);
     sinks.push_back(guard.op->getIn(1));	// The CPUI_LOAD pointer
   }
@@ -676,7 +673,7 @@ void Heritage::analyzeNewLoadGuards(void)
   for(iter=startIter;iter!=loadGuard.end(); ++iter) {
     LoadGuard &guard( *iter );
     guard.establishRange(vsSolver.getValueSetRead(guard.op->getSeqNum()));
-    if (!guard.isAnalyzed)
+    if (guard.analysisState == 0)
       runFullAnalysis = true;
   }
   if (runFullAnalysis) {
@@ -700,13 +697,7 @@ void Heritage::generateLoadGuard(StackNode &node,PcodeOp *op,AddrSpace *spc)
 
 {
   loadGuard.push_back(LoadGuard());
-  LoadGuard &guard( loadGuard.back() );
+  loadGuard.back().set(op,spc,node.offset);
-  guard.op = op;
-  guard.spc = spc;
-  guard.pointerBase = node.offset;
-  guard.minimumOffset = 0;			// Initially we guard everything
-  guard.maximumOffset = spc->getHighest();
-  guard.isAnalyzed = false;
 }
 
 /// \brief Trace input stackpointer to any indexed loads

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

@@ -95,6 +95,39 @@ class HeritageInfo {
     deadremoved = 0; deadcodedelay = delay; warningissued = false; loadGuardSearch = false; }	///< Reset
 };
 
+/// \brief Description of a LOAD operation that needs to be guarded
+///
+/// Heritage maintains a list of CPUI_LOAD ops that reference the stack dynamically. These
+/// can potentially alias stack Varnodes, so we maintain what (possibly limited) information
+/// we known about the range of stack addresses that can be referenced.
+class LoadGuard {
+  friend class Heritage;
+  PcodeOp *op;		///< The LOAD op
+  AddrSpace *spc;	///< The stack space being loaded from
+  uintb pointerBase;	///< Base offset of the pointer
+  uintb minimumOffset;	///< Minimum offset of the LOAD
+  uintb maximumOffset;	///< Maximum offset of the LOAD
+  int4 step;		///< Step of any access into this range (0=unknown)
+  int4 analysisState;	///< 0=unanalyzed, 1=analyzed(partial result), 2=analyzed(full result)
+  void establishRange(const ValueSetRead &valueSet);	///< Convert partial value set analysis into guard range
+  void finalizeRange(const ValueSetRead &valueSet);	///< Convert value set analysis to final guard range
+
+  /// \brief Set a new unanalyzed LOAD guard that initially guards everything
+  ///
+  /// \param o is the LOAD op
+  /// \param s is the (stack) space it is loading from
+  /// \param off is the base offset that is indexed from
+  void set(PcodeOp *o,AddrSpace *s,uintb off) {
+    op = o; spc = s; pointerBase=off; minimumOffset=0; maximumOffset=s->getHighest(); step=0; analysisState=0;
+  }
+public:
+  PcodeOp *getOp(void) const { return op; }	///< Get the PcodeOp being guarded
+  uintb getMinimum(void) const { return minimumOffset; }	///< Get minimum offset of the guarded range
+  uintb getMaximum(void) const { return maximumOffset; }	///< Get maximum offset of the guarded range
+  int4 getStep(void) const { return step; }		///< Get the calculated step associated with the range (or 0)
+  bool isRangeLocked(void) const { return (analysisState == 2); }	///< Return \b true if the range is fully determined
+};
+
 /// \brief Manage the construction of Static Single Assignment (SSA) form
 ///
 /// With a specific function (Funcdata), this class links the Varnode and
@@ -156,20 +189,6 @@ class Heritage {
     }
   };
 
-  /// \brief Description of a LOAD operation that needs to be guarded
-  class LoadGuard {
-    friend class Heritage;
-    PcodeOp *op;		///< The LOAD op
-    AddrSpace *spc;		///< The stack space being loaded from
-    uintb pointerBase;		///< Base offset of the pointer
-    uintb minimumOffset;	///< Minimum offset of the LOAD
-    uintb maximumOffset;	///< Maximum offset of the LOAD
-    int4 step;			///< Step of any access into this range
-    bool isAnalyzed;		///< Has a range analysis been performed on \b this
-    void establishRange(const ValueSetRead &valueSet);	///< Convert partial value set analysis into guard range
-    void finalizeRange(const ValueSetRead &valueSet);	///< Convert value set analysis to final guard range
-  };
-
   Funcdata *fd;		        ///< The function \b this is controlling SSA construction 
   LocationMap globaldisjoint;	///< Disjoint cover of every heritaged memory location
   LocationMap disjoint;		///< Disjoint cover of memory locations currently being heritaged
@@ -229,6 +248,8 @@ class Heritage {
   void calcMultiequals(const vector<Varnode *> &write);
   void renameRecurse(BlockBasic *bl,VariableStack &varstack);
   void bumpDeadcodeDelay(Varnode *vn);
+  void placeMultiequals(void);
+  void rename(void);
 public:
   Heritage(Funcdata *data);	///< Constructor
 
@@ -246,9 +267,8 @@ public:
   void buildInfoList(void);	                    ///< Initialize information for each space
   void forceRestructure(void) { maxdepth = -1; }    ///< Force regeneration of basic block structures
   void clear(void);				    ///< Reset all analysis of heritage
-  void placeMultiequals(void);
-  void rename(void);
   void heritage(void);				    ///< Perform one pass of heritage
+  const list<LoadGuard> &getLoadGuards(void) const { return loadGuard; }	///< Get list of LOAD ops that are guarded
 };
 
 #endif