Introduce bytecodes for assisting generator suspend and resume.

src/interpreter/bytecode-generator.cc

 // 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.
 
 #include "src/interpreter/bytecode-generator.h"
 
 #include "src/ast/scopes.h"
 #include "src/compiler.h"
 #include "src/interpreter/bytecode-register-allocator.h"
 #include "src/interpreter/control-flow-builders.h"
@@ skipping 626 matching lines @@
   builder()
       ->LoadAccumulatorWithRegister(Register::new_target())
       .JumpIfUndefined(&regular_call);
 
   // This is a resume call. Restore registers and perform state dispatch.
   // (The current context has already been restored by the trampoline.)
   {
     RegisterAllocationScope register_scope(this);
     Register state = register_allocator()->NewRegister();
     builder()
-        ->CallRuntime(Runtime::kResumeIgnitionGenerator, Register::new_target(),
-                      1)
+        ->ResumeGenerator(Register::new_target())
         .StoreAccumulatorInRegister(state);
 
     // TODO(neis): Optimize this by using a proper jump table.
     for (size_t i = 0; i < generator_resume_points_.size(); ++i) {
       builder()
           ->LoadLiteral(Smi::FromInt(static_cast<int>(i)))
           .CompareOperation(Token::Value::EQ_STRICT, state)
           .JumpIfTrue(&(generator_resume_points_[i]));
     }
     builder()->Illegal();  // Should never get here.
@@ skipping 1552 matching lines @@
   }
   execution_result()->SetResultInAccumulator();
 }
 
 void BytecodeGenerator::VisitYield(Yield* expr) {
   int id = generator_yields_seen_++;
 
   builder()->SetExpressionPosition(expr);
   Register value = VisitForRegisterValue(expr->expression());
 
-  register_allocator()->PrepareForConsecutiveAllocations(2);
-  Register generator = register_allocator()->NextConsecutiveRegister();
-  Register state = register_allocator()->NextConsecutiveRegister();
+  Register generator = VisitForRegisterValue(expr->generator_object());
 
   // Save context, registers, and state. Then return.
-  VisitForRegisterValue(expr->generator_object(), generator);
   builder()
       ->LoadLiteral(Smi::FromInt(id))
-      .StoreAccumulatorInRegister(state)
-      .CallRuntime(Runtime::kSuspendIgnitionGenerator, generator, 2)
+      .SuspendGenerator(generator)
       .LoadAccumulatorWithRegister(value)
       .Return();  // Hard return (ignore any finally blocks).
 
   builder()->Bind(&(generator_resume_points_[id]));
   // Upon resume, we continue here.
 
   {
     RegisterAllocationScope register_scope(this);
 
     Register input = register_allocator()->NewRegister();
@@ skipping 976 matching lines @@
 }
 
 
 int BytecodeGenerator::feedback_index(FeedbackVectorSlot slot) const {
   return info()->shared_info()->feedback_vector()->GetIndex(slot);
 }
 
 }  // namespace interpreter
 }  // namespace internal
 }  // namespace v8