[Interpreter] Optimize BytecodeArrayBuilder and BytecodeArrayWriter.

src/interpreter/bytecode-peephole-optimizer.cc

Index: src/interpreter/bytecode-peephole-optimizer.cc
diff --git a/src/interpreter/bytecode-peephole-optimizer.cc b/src/interpreter/bytecode-peephole-optimizer.cc
index 11aebb6ddb3ef1f3d85ac36196e0b57f37e4aef9..c87d31c39f04aef43254e8643af83c2672b1d8c6 100644
--- a/src/interpreter/bytecode-peephole-optimizer.cc
+++ b/src/interpreter/bytecode-peephole-optimizer.cc
@@ -13,17 +13,17 @@ namespace interpreter {
 
 BytecodePeepholeOptimizer::BytecodePeepholeOptimizer(
     BytecodePipelineStage* next_stage)
-    : next_stage_(next_stage) {
+    : next_stage_(next_stage), last_(Bytecode::kIllegal) {
   InvalidateLast();
 }
 
 // override
 Handle<BytecodeArray> BytecodePeepholeOptimizer::ToBytecodeArray(
-    Isolate* isolate, int fixed_register_count, int parameter_count,
+    Isolate* isolate, int register_count, int parameter_count,
     Handle<FixedArray> handler_table) {
   Flush();
-  return next_stage_->ToBytecodeArray(isolate, fixed_register_count,
-                                      parameter_count, handler_table);
+  return next_stage_->ToBytecodeArray(isolate, register_count, parameter_count,
+                                      handler_table);
 }
 
 // override
@@ -142,7 +142,7 @@ void TransformLdaSmiBinaryOpToBinaryOpWithSmi(Bytecode new_bytecode,
   current->set_bytecode(new_bytecode, last->operand(0), current->operand(0),
                         current->operand(1));
   if (last->source_info().is_valid()) {
-    current->source_info().Clone(last->source_info());
+    current->source_info_ptr()->Clone(last->source_info());
   }
 }
 
@@ -153,7 +153,7 @@ void TransformLdaZeroBinaryOpToBinaryOpWithZero(Bytecode new_bytecode,
   current->set_bytecode(new_bytecode, 0, current->operand(0),
                         current->operand(1));
   if (last->source_info().is_valid()) {
-    current->source_info().Clone(last->source_info());
+    current->source_info_ptr()->Clone(last->source_info());
   }
 }
 
@@ -223,7 +223,7 @@ void BytecodePeepholeOptimizer::ElideLastAction(
       // |node| can not have a valid source position if the source
       // position of last() is valid (per rules in
       // CanElideLastBasedOnSourcePosition()).
-      node->source_info().Clone(last()->source_info());
+      node->source_info_ptr()->Clone(last()->source_info());
     }
     SetLast(node);
   } else {
@@ -314,7 +314,7 @@ void BytecodePeepholeOptimizer::ElideLastBeforeJumpAction(
   if (!CanElideLastBasedOnSourcePosition(node)) {
     next_stage()->Write(last());
   } else if (!node->source_info().is_valid()) {
-    node->source_info().Clone(last()->source_info());
+    node->source_info_ptr()->Clone(last()->source_info());
   }
   InvalidateLast();
 }