[generators] Perform state dispatch in loop header.

src/interpreter/bytecode-generator.h

 // Copyright 2015 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_INTERPRETER_BYTECODE_GENERATOR_H_
 #define V8_INTERPRETER_BYTECODE_GENERATOR_H_
 
 #include "src/ast/ast.h"
 #include "src/interpreter/bytecode-array-builder.h"
 #include "src/interpreter/bytecodes.h"
@@ skipping 91 matching lines @@
   void BuildKeyedSuperPropertyLoad(Register receiver, Register home_object,
                                    Register key);
 
   void BuildThrowIfHole(Handle<String> name);
   void BuildThrowIfNotHole(Handle<String> name);
   void BuildThrowReassignConstant(Handle<String> name);
   void BuildThrowReferenceError(Handle<String> name);
   void BuildHoleCheckForVariableLoad(VariableMode mode, Handle<String> name);
   void BuildHoleCheckForVariableAssignment(Variable* variable, Token::Value op);
 
+  // Build jump to targets[value], where
+  // start_index <= value < start_index + size.
+  void BuildIndexedJump(Register value, size_t start_index, size_t size,
+                        ZoneVector<BytecodeLabel>& targets);
+
   void VisitGeneratorPrologue();
 
   void VisitArgumentsObject(Variable* variable);
   void VisitRestArgumentsArray(Variable* rest);
   void VisitCallSuper(Call* call);
   void VisitClassLiteralContents(ClassLiteral* expr);
   void VisitClassLiteralForRuntimeDefinition(ClassLiteral* expr);
   void VisitClassLiteralProperties(ClassLiteral* expr, Register literal,
                                    Register prototype);
   void VisitClassLiteralStaticPrototypeWithComputedName(Register name);
   void VisitThisFunctionVariable(Variable* variable);
   void VisitNewTargetVariable(Variable* variable);
   void VisitNewLocalFunctionContext();
   void VisitBuildLocalActivationContext();
   void VisitBlockDeclarationsAndStatements(Block* stmt);
   void VisitNewLocalBlockContext(Scope* scope);
   void VisitNewLocalCatchContext(Variable* variable);
   void VisitNewLocalWithContext();
   void VisitFunctionClosureForContext();
   void VisitSetHomeObject(Register value, Register home_object,
                           ObjectLiteralProperty* property, int slot_number = 0);
   void VisitObjectLiteralAccessor(Register home_object,
                                   ObjectLiteralProperty* property,
                                   Register value_out);
   void VisitForInAssignment(Expression* expr, FeedbackVectorSlot slot);
 
-  // Visit the body of a loop iteration.
+  // Visit the header/body of a loop iteration.
+  void VisitIterationHeader(IterationStatement* stmt,
+                            LoopBuilder* loop_builder);
   void VisitIterationBody(IterationStatement* stmt, LoopBuilder* loop_builder);
 
   // Visit a statement and switch scopes, the context is in the accumulator.
   void VisitInScope(Statement* stmt, Scope* scope);
 
   // Visitors for obtaining expression result in the accumulator, in a
   // register, or just getting the effect.
   void VisitForAccumulatorValue(Expression* expr);
   void VisitForAccumulatorValueOrTheHole(Expression* expr);
   MUST_USE_RESULT Register VisitForRegisterValue(Expression* expr);
@@ skipping 46 matching lines @@
   Zone* zone_;
   BytecodeArrayBuilder* builder_;
   CompilationInfo* info_;
   Scope* scope_;
   ZoneVector<Handle<Object>> globals_;
   ControlScope* execution_control_;
   ContextScope* execution_context_;
   ExpressionResultScope* execution_result_;
   RegisterAllocationScope* register_allocator_;
   ZoneVector<BytecodeLabel> generator_resume_points_;
+  Register generator_state_;
+  size_t generator_yields_seen_;
   int try_catch_nesting_level_;
   int try_finally_nesting_level_;
-  int generator_yields_seen_;
 };
 
 }  // namespace interpreter
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_INTERPRETER_BYTECODE_GENERATOR_H_