WIP [esnext] implement async iteration proposal

src/code-stub-assembler.h

 // Copyright 2016 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_CODE_STUB_ASSEMBLER_H_
 #define V8_CODE_STUB_ASSEMBLER_H_
 
 #include <functional>
 
 #include "src/compiler/code-assembler.h"
@@ skipping 1119 matching lines @@
 
   Node* Typeof(Node* value, Node* context);
 
   Node* GetSuperConstructor(Node* value, Node* context);
 
   Node* InstanceOf(Node* object, Node* callable, Node* context);
 
   // Debug helpers
   Node* IsDebugActive();
 
+  // Useful tools for PrintF-style debugging CSA builtins.
+  void ReleasePrint(const char* c_str) {
+    std::string std_str(c_str);
+    std_str += '\n';
+    Handle<String> str =
+        factory()->NewStringFromAsciiChecked(std_str.c_str(), TENURED);
+    CallRuntime(Runtime::kGlobalPrint, NoContextConstant(), HeapConstant(str));
+  }
+
+  void ReleaseDebugPrint(Node* object) {
+    CallRuntime(Runtime::kDebugPrint, NoContextConstant(), object);
+  }
+
+  void Print(const char* c_str) {
+#ifdef DEBUG
+    ReleasePrint(c_str);
+#endif
+  }
+
+  void DebugPrint(Node* object) {
+#ifdef DEBUG
+    ReleaseDebugPrint(object);
+#endif
+  }
+
   // TypedArray/ArrayBuffer helpers
   Node* IsDetachedBuffer(Node* buffer);
 
   Node* ElementOffsetFromIndex(Node* index, ElementsKind kind,
                                ParameterMode mode, int base_size = 0);
 
   Node* AllocateFunctionWithMapAndContext(Node* map, Node* shared_info,
                                           Node* context);
 
   // Promise helpers
@@ skipping 123 matching lines @@
   }
 #else
 #define CSA_SLOW_ASSERT(csa, x) ((void)0)
 #endif
 
 DEFINE_OPERATORS_FOR_FLAGS(CodeStubAssembler::AllocationFlags);
 
 }  // namespace internal
 }  // namespace v8
 #endif  // V8_CODE_STUB_ASSEMBLER_H_