ART: Refactor iteration over normal/exceptional successors

Add helper methods on HBasicBlock which return ArrayRef with the
suitable sub-array of the `successors_` list.

Change-Id: I66c83bb56f2984d7550bf77c48110af4087515a8
diff --git a/compiler/optimizing/nodes.h b/compiler/optimizing/nodes.h
index 4421419..a3f3d17 100644
--- a/compiler/optimizing/nodes.h
+++ b/compiler/optimizing/nodes.h
@@ -35,6 +35,7 @@
 #include "mirror/class.h"
 #include "offsets.h"
 #include "primitive.h"
+#include "utils/array_ref.h"
 
 namespace art {
 
@@ -660,6 +661,9 @@
     return successors_;
   }
 
+  ArrayRef<HBasicBlock* const> GetNormalSuccessors() const;
+  ArrayRef<HBasicBlock* const> GetExceptionalSuccessors() const;
+
   bool HasSuccessor(const HBasicBlock* block, size_t start_from = 0u) {
     return ContainsElement(successors_, block, start_from);
   }
@@ -810,12 +814,6 @@
     return GetPredecessorIndexOf(predecessor) == idx;
   }
 
-  // Returns the number of non-exceptional successors. SsaChecker ensures that
-  // these are stored at the beginning of the successor list.
-  size_t NumberOfNormalSuccessors() const {
-    return EndsWithTryBoundary() ? 1 : GetSuccessors().size();
-  }
-
   // Create a new block between this block and its predecessors. The new block
   // is added to the graph, all predecessor edges are relinked to it and an edge
   // is created to `this`. Returns the new empty block. Reverse post order or
@@ -2398,6 +2396,10 @@
   // Returns the block's non-exceptional successor (index zero).
   HBasicBlock* GetNormalFlowSuccessor() const { return GetBlock()->GetSuccessors()[0]; }
 
+  ArrayRef<HBasicBlock* const> GetExceptionHandlers() const {
+    return ArrayRef<HBasicBlock* const>(GetBlock()->GetSuccessors()).SubArray(1u);
+  }
+
   // Returns whether `handler` is among its exception handlers (non-zero index
   // successors).
   bool HasExceptionHandler(const HBasicBlock& handler) const {
@@ -2425,25 +2427,6 @@
   DISALLOW_COPY_AND_ASSIGN(HTryBoundary);
 };
 
-// Iterator over exception handlers of a given HTryBoundary, i.e. over
-// exceptional successors of its basic block.
-class HExceptionHandlerIterator : public ValueObject {
- public:
-  explicit HExceptionHandlerIterator(const HTryBoundary& try_boundary)
-    : block_(*try_boundary.GetBlock()), index_(block_.NumberOfNormalSuccessors()) {}
-
-  bool Done() const { return index_ == block_.GetSuccessors().size(); }
-  HBasicBlock* Current() const { return block_.GetSuccessors()[index_]; }
-  size_t CurrentSuccessorIndex() const { return index_; }
-  void Advance() { ++index_; }
-
- private:
-  const HBasicBlock& block_;
-  size_t index_;
-
-  DISALLOW_COPY_AND_ASSIGN(HExceptionHandlerIterator);
-};
-
 // Deoptimize to interpreter, upon checking a condition.
 class HDeoptimize : public HTemplateInstruction<1> {
  public: