[BOLT] Make DataflowAnalysis::getStateBefore() const (NFC)

Author: atrosinenko

bolt/include/bolt/Passes/DataflowAnalysis.h

@@ -292,14 +292,17 @@ class DataflowAnalysis {
   /// Relies on a ptr map to fetch the previous instruction and then retrieve
   /// state. WARNING: Watch out for invalidated pointers. Do not use this
   /// function if you invalidated pointers after the analysis has been completed
-  ErrorOr<const StateTy &> getStateBefore(const MCInst &Point) {
-    return getStateAt(PrevPoint[&Point]);
+  ErrorOr<const StateTy &> getStateBefore(const MCInst &Point) const {
+    auto It = PrevPoint.find(&Point);
+    if (It == PrevPoint.end())
+      return make_error_code(std::errc::result_out_of_range);
+    return getStateAt(It->getSecond());
   }
 
-  ErrorOr<const StateTy &> getStateBefore(ProgramPoint Point) {
+  ErrorOr<const StateTy &> getStateBefore(ProgramPoint Point) const {
     if (Point.isBB())
       return getStateAt(*Point.getBB());
-    return getStateAt(PrevPoint[Point.getInst()]);
+    return getStateBefore(*Point.getInst());
   }
 
   /// Remove any state annotations left by this analysis

bolt/lib/Passes/PAuthGadgetScanner.cpp

@@ -448,7 +448,7 @@ class PacRetAnalysis
 public:
   std::vector<MCInstReference>
   getLastClobberingInsts(const MCInst &Inst, BinaryFunction &BF,
-                         const ArrayRef<MCPhysReg> UsedDirtyRegs) {
+                         const ArrayRef<MCPhysReg> UsedDirtyRegs) const {
     if (RegsToTrackInstsFor.empty())
       return {};
     auto MaybeState = getStateBefore(Inst);