Rename the successor field of instruction to next.

runtime/vm/intermediate_language.h

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #ifndef VM_INTERMEDIATE_LANGUAGE_H_
 #define VM_INTERMEDIATE_LANGUAGE_H_
 
 #include "vm/allocation.h"
 #include "vm/ast.h"
 #include "vm/growable_array.h"
@@ skipping 1704 matching lines @@
   virtual const char* DebugName() const { return #type; }                      \
   virtual void PrintTo(BufferFormatter* f) const;                              \
   virtual void PrintToVisualizer(BufferFormatter* f) const;
 
 
 class Instruction : public ZoneAllocated {
  public:
   Instruction()
       : cid_(-1),
         ic_data_(NULL),
-        successor_(NULL),
         previous_(NULL),
+        next_(NULL),
         env_(NULL) {
     Isolate* isolate = Isolate::Current();
     cid_ = Computation::GetNextCid(isolate);
     ic_data_ = Computation::GetICDataForCid(cid_, isolate);
   }
 
   // Unique computation/instruction id, used for deoptimization, e.g. for
   // ReturnInstr, ThrowInstr and ReThrowInstr.
   intptr_t cid() const { return cid_; }
 
   const ICData* ic_data() const { return ic_data_; }
 
   virtual bool IsBlockEntry() const { return false; }
   BlockEntryInstr* AsBlockEntry() {
     return IsBlockEntry() ? reinterpret_cast<BlockEntryInstr*>(this) : NULL;
   }
   virtual bool IsDefinition() const { return false; }
   virtual Definition* AsDefinition() { return NULL; }
 
   virtual intptr_t InputCount() const = 0;
   virtual Value* InputAt(intptr_t i) const = 0;
   virtual void SetInputAt(intptr_t i, Value* value) = 0;
 
   // Visiting support.
   virtual Instruction* Accept(FlowGraphVisitor* visitor) = 0;
 
-  Instruction* successor() const { return successor_; }
-  void set_successor(Instruction* instr) {
+  Instruction* previous() const { return previous_; }
+  void set_previous(Instruction* instr) {
+    ASSERT(!IsBlockEntry());
+    previous_ = instr;
+  }
+
+  Instruction* next() const { return next_; }
+  void set_next(Instruction* instr) {
     ASSERT(!IsGraphEntry());
     ASSERT(!IsReturn());
     ASSERT(!IsBranch());
     ASSERT(!IsPhi());

[srdjan, 2012/07/09 17:08:25]

Why not make this virtual and make this UNREACHABLE for the instructions?

     // TODO(fschneider): Also add Throw and ReThrow to the list of instructions
     // that do not have a successor. Currently, the graph builder will continue
     // to append instruction in case of a Throw inside an expression. This
     // condition should be handled in the graph builder
-    successor_ = instr;
-  }
-
-  Instruction* previous() const { return previous_; }
-  void set_previous(Instruction* instr) {
-    ASSERT(!IsBlockEntry());
-    previous_ = instr;
+    next_ = instr;
   }
 
   // Normal instructions can have 0 (inside a block) or 1 (last instruction in
   // a block) successors. Branch instruction with >1 successors override this
   // function.
   virtual intptr_t SuccessorCount() const;
   virtual BlockEntryInstr* SuccessorAt(intptr_t index) const;
 
   // Discover basic-block structure by performing a recursive depth first
   // traversal of the instruction graph reachable from this instruction.  As
@@ skipping 51 matching lines @@
   virtual void EmitNativeCode(FlowGraphCompiler* compiler) {
     UNIMPLEMENTED();
   }
 
   Environment* env() const { return env_; }
   void set_env(Environment* env) { env_ = env; }
 
  private:
   intptr_t cid_;
   ICData* ic_data_;
-  Instruction* successor_;
   Instruction* previous_;
+  Instruction* next_;
   Environment* env_;
   DISALLOW_COPY_AND_ASSIGN(Instruction);
 };
 
 
 class InstructionWithInputs : public Instruction {
  public:
   InstructionWithInputs() : locs_(NULL) {
   }
 
@@ skipping 80 matching lines @@
 
 
 class ForwardInstructionIterator : public ValueObject {
  public:
   explicit ForwardInstructionIterator(BlockEntryInstr* block_entry)
       : block_entry_(block_entry), current_(block_entry) {
     Advance();
   }
 
   void Advance() {
-    if (!Done()) current_ = current_->successor();
+    if (!Done()) current_ = current_->next();
   }
 
   bool Done() const {
-    return current_ == block_entry_->last_instruction()->successor();
+    return current_ == block_entry_->last_instruction()->next();
   }
 
   void RemoveCurrentFromGraph() {
     ASSERT(!current_->IsBlockEntry());
     ASSERT(!current_->IsBranch());
     ASSERT(!current_->IsThrow());
     ASSERT(!current_->IsReturn());
     ASSERT(!current_->IsReThrow());
     ASSERT(current_->previous() != NULL);
-    Instruction* next = current_->successor();
     Instruction* prev = current_->previous();
-    prev->set_successor(next);
+    Instruction* next = current_->next();
+    prev->set_next(next);
     ASSERT(next != NULL);
     if (current_ != block_entry_->last_instruction()) {
       ASSERT(!next->IsBlockEntry());
       next->set_previous(prev);
     } else {
       ASSERT(current_->IsBind());
       // Removing the last instruction of a block.
       // Update last_instruction of the current basic block.
       block_entry_->set_last_instruction(prev);
     }
     // Reset successor and previous instruction to indicate
     // that the instruction is removed from the graph.
-    current_->set_successor(NULL);
     current_->set_previous(NULL);
+    current_->set_next(NULL);
     current_ = prev;
   }
 
   Instruction* Current() const { return current_; }
 
  private:
   BlockEntryInstr* block_entry_;
   Instruction* current_;
 };
 
@@ skipping 451 matching lines @@
   const GrowableArray<BlockEntryInstr*>& block_order_;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(FlowGraphVisitor);
 };
 
 
 }  // namespace dart
 
 #endif  // VM_INTERMEDIATE_LANGUAGE_H_