[g-arc-opts] Refactor ARCBBState from GlobalARCSequenceDataflow.cpp -> *.h.

Swift SVN r18690

lib/SILAnalysis/GlobalARCSequenceDataflow.h

@@ -23,6 +23,104 @@ class AliasAnalysis;
 namespace swift {
 namespace arc {
 
+/// \brief Per-BasicBlock state.
+class ARCBBState {
+public:
+  using TopDownMapTy = BlotMapVector<SILValue, TopDownRefCountState>;
+  using BottomUpMapTy = BlotMapVector<SILValue, BottomUpRefCountState>;
+
+private:
+  /// The basic block that this bbstate corresponds to.
+  SILBasicBlock *BB;
+
+  /// The top-down traversal uses this to record information known about a
+  /// pointer at the bottom of each block.
+  TopDownMapTy PtrToTopDownState;
+
+  /// The bottom-up traversal uses this to record information known about a
+  /// pointer at the top of each block.
+  BottomUpMapTy PtrToBottomUpState;
+
+public:
+  ARCBBState() : BB() {}
+  ARCBBState(SILBasicBlock *BB) : BB(BB) {}
+
+  void init(SILBasicBlock *NewBB) {
+    assert(NewBB && "Cannot set NewBB to a nullptr.");
+    BB = NewBB;
+  }
+
+  /// Top Down Iterators
+  using topdown_iterator = TopDownMapTy::iterator;
+  using topdown_const_iterator = TopDownMapTy::const_iterator;
+  topdown_iterator topdown_begin() { return PtrToTopDownState.begin(); }
+  topdown_iterator topdown_end() { return PtrToTopDownState.end(); }
+  topdown_const_iterator topdown_begin() const {
+    return PtrToTopDownState.begin();
+  }
+  topdown_const_iterator topdown_end() const { return PtrToTopDownState.end(); }
+  Range<topdown_iterator> getTopDownStates() {
+    return make_range(topdown_begin(), topdown_end());
+  }
+
+  /// Bottom up iteration.
+  using bottomup_iterator = BottomUpMapTy::iterator;
+  using bottomup_const_iterator = BottomUpMapTy::const_iterator;
+  bottomup_iterator bottomup_begin() { return PtrToBottomUpState.begin(); }
+  bottomup_iterator bottomup_end() { return PtrToBottomUpState.end(); }
+  bottomup_const_iterator bottomup_begin() const {
+    return PtrToBottomUpState.begin();
+  }
+  bottomup_const_iterator bottomup_end() const {
+    return PtrToBottomUpState.end();
+  }
+  Range<bottomup_iterator> getBottomupStates() {
+    return make_range(bottomup_begin(), bottomup_end());
+  }
+
+  /// Attempt to find the PtrState object describing the top down state for
+  /// pointer Arg. Return a new initialized PtrState describing the top down
+  /// state for Arg if we do not find one.
+  TopDownRefCountState &getTopDownRefCountState(SILValue Ptr) {
+    return PtrToTopDownState[Ptr];
+  }
+
+  /// Attempt to find the PtrState object describing the bottom up state for
+  /// pointer Arg. Return a new initialized PtrState describing the bottom up
+  /// state for Arg if we do not find one.
+  BottomUpRefCountState &getBottomUpRefCountState(SILValue Ptr) {
+    return PtrToBottomUpState[Ptr];
+  }
+
+  void clearTopDownState() { PtrToTopDownState.clear(); }
+
+  void clearBottomUpState() { PtrToBottomUpState.clear(); }
+
+  /// Clear both the bottom up *AND* top down state.
+  void clear() {
+    clearTopDownState();
+    clearBottomUpState();
+  }
+
+  /// Returns a reference to the basic block that we are tracking.
+  SILBasicBlock &getBB() const { return *BB; }
+
+  /// Merge in the state of the successor basic block. This is currently a stub.
+  void mergeSuccBottomUp(ARCBBState &SuccBB);
+
+  /// Initialize this BB with the state of the successor basic block. This is
+  /// called on a basic block's state and then any other successors states are
+  /// merged in. This is currently a stub.
+  void initSuccBottomUp(ARCBBState &SuccBB);
+
+  /// Merge in the state of the predecessor basic block. This is currently a stub.
+  void mergePredTopDown(ARCBBState &PredBB);
+
+  /// Initialize the state for this BB with the state of its predecessor
+  /// BB. Used to create an initial state before we merge in other
+  /// predecessors. This is currently a stub.
+  void initPredTopDown(ARCBBState &PredBB);
+};
 bool performARCSequenceDataflow(
     SILFunction &F, AliasAnalysis *AA,
     BlotMapVector<SILInstruction *, TopDownRefCountState> &DecToIncStateMap,