[generators] Perform state dispatch in loop header.

src/interpreter/bytecode-array-builder.h

Index: src/interpreter/bytecode-array-builder.h
diff --git a/src/interpreter/bytecode-array-builder.h b/src/interpreter/bytecode-array-builder.h
index 4ad9ff995a1ce74bb3ed34928fba90180048d3fe..f3440e2a3f86dfbfa1a34ae7479a7b8836429dae 100644
--- a/src/interpreter/bytecode-array-builder.h
+++ b/src/interpreter/bytecode-array-builder.h
@@ -224,6 +224,10 @@ class BytecodeArrayBuilder final : public ZoneObject {
   BytecodeArrayBuilder& JumpIfNull(BytecodeLabel* label);
   BytecodeArrayBuilder& JumpIfUndefined(BytecodeLabel* label);
 
+  // Jump to targets[value], where min <= value < min + size.
+  BytecodeArrayBuilder& IndexedJump(Register value, int min, size_t size,
+                                    ZoneVector<BytecodeLabel>& targets);
+
   BytecodeArrayBuilder& StackCheck();
 
   BytecodeArrayBuilder& Throw();
@@ -285,6 +289,10 @@ class BytecodeArrayBuilder final : public ZoneObject {
   static uint32_t UnsignedOperand(int value);
   static uint32_t UnsignedOperand(size_t value);
 
+  ZoneVector<BytecodeLabel> generator_resume_points;
+  int generator_yields_seen() const { return generator_yields_seen_; }
+  int incr_generator_yields_seen() { return generator_yields_seen_++; }
+
  private:
   class PreviousBytecodeHelper;
   friend class BytecodeRegisterAllocator;
@@ -377,6 +385,7 @@ class BytecodeArrayBuilder final : public ZoneObject {
   int context_register_count_;
   int return_position_;
   TemporaryRegisterAllocator temporary_allocator_;
+  int generator_yields_seen_;
 
   DISALLOW_COPY_AND_ASSIGN(BytecodeArrayBuilder);
 };