[BOLT] Add ability to specify custom printers for annotations.

Summary:
This will give us the ability to print annotations in a more meaningful way.  Especially annotations that could be interpreted in multiple ways.  I've added one register name printer for liveness analysis.  We can update the other dataflow annotations as needed.

I also noticed that BitVector annotations were leaking since they contain heap allocated memory.  I made removeAnnotation call the annotation destructor explicitly to mitigate this but it won't fix the problem when annotations are just dropped en masse.

(cherry picked from FBD6105999)

Author: Bill Nell

bolt/Passes/DataflowAnalysis.cpp

@@ -1,6 +1,12 @@
 #include "DataflowAnalysis.h"
 
 namespace llvm {
+
+raw_ostream &operator<<(raw_ostream &OS, const BitVector &Val) {
+  OS << "BitVector";
+  return OS;
+}
+
 namespace bolt {
 
 void doForAllPreds(const BinaryContext &BC, const BinaryBasicBlock &BB,
@@ -30,11 +36,11 @@ void doForAllSuccs(const BinaryBasicBlock &BB,
   }
 }
 
+void RegStatePrinter::print(raw_ostream &OS, const BitVector &State) const {
+  for (auto I = State.find_first(); I != -1; I = State.find_next(I)) {
+    OS << BC.MRI->getName(I) << " ";
+  }
+}
+
 } // namespace bolt
 } // namespace llvm
-
-llvm::raw_ostream &llvm::operator<<(llvm::raw_ostream &OS,
-                                    const BitVector &Val) {
-  OS << "BitVector";
-  return OS;
-}

bolt/Passes/DataflowAnalysis.h

@@ -105,6 +105,25 @@ void doForAllPreds(const BinaryContext &BC, const BinaryBasicBlock &BB,
 void doForAllSuccs(const BinaryBasicBlock &BB,
                    std::function<void(ProgramPoint)> Task);
 
+/// Default printer for State data.
+template <typename StateTy>
+class StatePrinter {
+public:
+  void print(raw_ostream &OS, const StateTy &State) const {
+    OS << State;
+  }
+  explicit StatePrinter(const BinaryContext &) { }
+};
+
+/// Printer for State data that is a BitVector of registers.
+class RegStatePrinter {
+public:
+  void print(raw_ostream &OS, const BitVector &State) const;
+  explicit RegStatePrinter(const BinaryContext &BC) : BC(BC) { }
+private:
+  const BinaryContext &BC;
+};
+
 /// Base class for dataflow analyses. Depends on the type of whatever object is
 /// stored as the state (StateTy) at each program point. The dataflow then
 /// updates the state at each program point depending on the instruction being
@@ -132,7 +151,10 @@ void doForAllSuccs(const BinaryBasicBlock &BB,
 ///     Confluence operator = union  (if a reg is alive in any succ, it is alive
 ///     in the current block).
 ///
-template <typename Derived, typename StateTy, bool Backward=false>
+template <typename Derived,
+          typename StateTy,
+          bool Backward = false,
+          typename StatePrinterTy = StatePrinter<StateTy>>
 class DataflowAnalysis {
   /// CRTP convenience methods
   Derived &derived() {
@@ -212,7 +234,7 @@ class DataflowAnalysis {
 
   StateTy &getOrCreateStateAt(MCInst &Point) {
     return BC.MIA->getOrCreateAnnotationAs<StateTy>(
-        BC.Ctx.get(), Point, derived().getAnnotationName());
+        BC.Ctx.get(), Point, derived().getAnnotationName(), StatePrinterTy(BC));
   }
 
   StateTy &getOrCreateStateAt(ProgramPoint Point) {
@@ -272,7 +294,7 @@ class DataflowAnalysis {
     return getStateAt(PrevPoint[&Point]);
   }
 
-  ErrorOr<const StateTy &>getStateBefore(ProgramPoint Point) {
+  ErrorOr<const StateTy &> getStateBefore(ProgramPoint Point) {
     if (Point.isBB())
       return getStateAt(*Point.getBB());
     return getStateAt(PrevPoint[Point.getInst()]);
@@ -462,9 +484,11 @@ class ExprIterator
 
 /// Specialization of DataflowAnalysis whose state specifically stores
 /// a set of instructions.
-template <typename Derived, bool Backward = false>
+template <typename Derived,
+          bool Backward = false,
+          typename StatePrinterTy = StatePrinter<BitVector>>
 class InstrsDataflowAnalysis
-    : public DataflowAnalysis<Derived, BitVector, Backward> {
+    : public DataflowAnalysis<Derived, BitVector, Backward, StatePrinterTy> {
 public:
   /// These iterator functions offer access to the set of pointers to
   /// instructions in a given program point
@@ -512,7 +536,7 @@ class InstrsDataflowAnalysis
   }
 
   InstrsDataflowAnalysis(const BinaryContext &BC, BinaryFunction &BF)
-      : DataflowAnalysis<Derived, BitVector, Backward>(BC, BF) {}
+    : DataflowAnalysis<Derived, BitVector, Backward, StatePrinterTy>(BC, BF) {}
   virtual ~InstrsDataflowAnalysis() {}
 };
 
@@ -541,8 +565,7 @@ template<> struct DenseMapInfo<bolt::ProgramPoint> {
   }
 };
 
-llvm::raw_ostream &operator<<(llvm::raw_ostream &OS,
-                              const BitVector &Val);
+raw_ostream &operator<<(raw_ostream &OS, const BitVector &Val);
 
 } // namespace llvm
 

bolt/Passes/LivenessAnalysis.h

@@ -26,14 +26,20 @@ namespace llvm {
 namespace bolt {
 
 class LivenessAnalysis
-    : public DataflowAnalysis<LivenessAnalysis, BitVector, true> {
-  friend class DataflowAnalysis<LivenessAnalysis, BitVector, true>;
+  : public DataflowAnalysis<LivenessAnalysis, BitVector, true, RegStatePrinter> {
+  using Parent = DataflowAnalysis<LivenessAnalysis,
+                                  BitVector,
+                                  true,
+                                  RegStatePrinter>;
+  friend class DataflowAnalysis<LivenessAnalysis,
+                                BitVector,
+                                true,
+                                RegStatePrinter>;
 
 public:
   LivenessAnalysis(const RegAnalysis &RA, const BinaryContext &BC,
                    BinaryFunction &BF)
-      : DataflowAnalysis<LivenessAnalysis, BitVector, true>(BC, BF), RA(RA),
-        NumRegs(BC.MRI->getNumRegs()) {}
+      : Parent(BC, BF), RA(RA), NumRegs(BC.MRI->getNumRegs()) {}
   virtual ~LivenessAnalysis();
 
   bool isAlive(ProgramPoint PP, MCPhysReg Reg) const {
@@ -45,7 +51,7 @@ class LivenessAnalysis
 
   void run() {
     NamedRegionTimer T1("LA", "Dataflow", opts::TimeOpts);
-    DataflowAnalysis<LivenessAnalysis, BitVector, true>::run();
+    Parent::run();
   }
 
   // Return a usable general-purpose reg after point P. Return 0 if no reg is
@@ -122,5 +128,4 @@ class LivenessAnalysis
 } // end namespace bolt
 } // end namespace llvm
 
-
 #endif