[turbofan] remove some of the dependency of Instruction on Schedule

src/compiler/schedule.h

Index: src/compiler/schedule.h
diff --git a/src/compiler/schedule.h b/src/compiler/schedule.h
index 7def37f44597279da04c7a6404803dc60b5d5c31..67b2600c7fb62642b341040ab1d4152359dcf09b 100644
--- a/src/compiler/schedule.h
+++ b/src/compiler/schedule.h
@@ -50,24 +50,28 @@ class BasicBlock FINAL : public ZoneObject {
     size_t index_;
   };
 
+  class RpoNumber FINAL {
+   public:
+    int ToInt() const { return static_cast<int>(index_); }
+    size_t ToSize() const { return index_; }
+    static RpoNumber FromInt(int index) {
+      return RpoNumber(static_cast<size_t>(index));
+    }
+    static RpoNumber Invalid() { return RpoNumber(static_cast<size_t>(-1)); }
+
+    bool IsNext(const RpoNumber other) const {
+      return other.index_ == this->index_ + 1;
+    }
+
+   private:
+    explicit RpoNumber(size_t index) : index_(index) {}
+    size_t index_;
+  };
+
   BasicBlock(Zone* zone, Id id);
 
   Id id() const { return id_; }
 
-  // Instruction indexes (used by the register allocator).
-  int first_instruction_index() {
-    DCHECK(code_start_ >= 0);
-    DCHECK(code_end_ > 0);
-    DCHECK(code_end_ >= code_start_);
-    return code_start_;
-  }
-  int last_instruction_index() {
-    DCHECK(code_start_ >= 0);
-    DCHECK(code_end_ > 0);
-    DCHECK(code_end_ >= code_start_);
-    return code_end_ - 1;
-  }
-
   // Predecessors and successors.
   typedef ZoneVector<BasicBlock*> Predecessors;
   Predecessors::iterator predecessors_begin() { return predecessors_.begin(); }
@@ -126,17 +130,10 @@ class BasicBlock FINAL : public ZoneObject {
   int32_t loop_end() const { return loop_end_; }
   void set_loop_end(int32_t loop_end);
 
+  RpoNumber GetRpoNumber() const { return RpoNumber::FromInt(rpo_number_); }
   int32_t rpo_number() const { return rpo_number_; }
   void set_rpo_number(int32_t rpo_number);
 
-  int32_t code_start() const { return code_start_; }
-  void set_code_start(int32_t start);
-
-  int32_t code_end() const { return code_end_; }
-  void set_code_end(int32_t end);
-
-  bool deferred() const { return deferred_; }
-
   // Loop membership helpers.
   inline bool IsLoopHeader() const { return loop_end_ >= 0; }
   bool LoopContains(BasicBlock* block) const;
@@ -150,10 +147,7 @@ class BasicBlock FINAL : public ZoneObject {
                              // enclosing loop header.
   int32_t loop_depth_;       // loop nesting, 0 is top-level
   int32_t loop_end_;         // end of the loop, if this block is a loop header.
-  int32_t code_start_;       // start index of arch-specific code.
-  int32_t code_end_;         // end index of arch-specific code.
-  bool deferred_;            // {true} if this block is considered the slow
-                             // path.
+
   Control control_;          // Control at the end of the block.
   Node* control_input_;      // Input value for control.
   NodeVector nodes_;         // nodes of this block in forward order.