WIP [esnext] implement async iteration proposal

src/builtins/x64/builtins-x64.cc

 // Copyright 2012 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.
 
 #if V8_TARGET_ARCH_X64
 
 #include "src/code-factory.h"
 #include "src/codegen.h"
 #include "src/deoptimizer.h"
 #include "src/full-codegen/full-codegen.h"
@@ skipping 422 matching lines @@
 
 void Builtins::Generate_JSEntryTrampoline(MacroAssembler* masm) {
   Generate_JSEntryTrampolineHelper(masm, false);
 }
 
 void Builtins::Generate_JSConstructEntryTrampoline(MacroAssembler* masm) {
   Generate_JSEntryTrampolineHelper(masm, true);
 }
 
 // static
-void Builtins::Generate_ResumeGeneratorTrampoline(MacroAssembler* masm) {
+void Builtins::Generate_ResumeGenerator(MacroAssembler* masm,
+                                        ResumeGeneratorType type) {
   // ----------- S t a t e -------------
   //  -- rax    : the value to pass to the generator
   //  -- rbx    : the JSGeneratorObject to resume
   //  -- rdx    : the resume mode (tagged)
   //  -- rsp[0] : return address
   // -----------------------------------
-  __ AssertGeneratorObject(rbx);
 
   // Store input value into generator object.
-  __ movp(FieldOperand(rbx, JSGeneratorObject::kInputOrDebugPosOffset), rax);
-  __ RecordWriteField(rbx, JSGeneratorObject::kInputOrDebugPosOffset, rax, rcx,
-                      kDontSaveFPRegs);
+  int offset = type == ResumeGeneratorType::kYield
+                   ? JSGeneratorObject::kInputOrDebugPosOffset
+                   : JSAsyncGeneratorObject::kAwaitInputOffset;
+  __ movp(FieldOperand(rbx, offset), rax);
+  __ RecordWriteField(rbx, offset, rax, rcx, kDontSaveFPRegs);
 
   // Store resume mode into generator object.
   __ movp(FieldOperand(rbx, JSGeneratorObject::kResumeModeOffset), rdx);
 
   // Load suspended function and context.
   __ movp(rsi, FieldOperand(rbx, JSGeneratorObject::kContextOffset));
   __ movp(rdi, FieldOperand(rbx, JSGeneratorObject::kFunctionOffset));
 
   // Flood function if we are stepping.
   Label prepare_step_in_if_stepping, prepare_step_in_suspended_generator;
@@ skipping 86 matching lines @@
     __ Push(rbx);
     __ Push(rdx);
     __ CallRuntime(Runtime::kDebugPrepareStepInSuspendedGenerator);
     __ Pop(rdx);
     __ Pop(rbx);
     __ movp(rdi, FieldOperand(rbx, JSGeneratorObject::kFunctionOffset));
   }
   __ jmp(&stepping_prepared);
 }
 
+// static
+void Builtins::Generate_ResumeGeneratorTrampoline(MacroAssembler* masm) {
+  // ----------- S t a t e -------------
+  //  -- rax    : the value to pass to the generator
+  //  -- rbx    : the JSGeneratorObject to resume
+  //  -- rdx    : the resume mode (tagged)
+  //  -- rsp[0] : return address
+  // -----------------------------------
+  __ AssertGeneratorObject(rbx);
+  Generate_ResumeGenerator(masm, ResumeGeneratorType::kYield);
+}
+
+// static
+void Builtins::Generate_ResumeAwaitedGeneratorTrampoline(MacroAssembler* masm) {
+  // ----------- S t a t e -------------
+  //  -- rax    : the value to pass to the generator
+  //  -- rbx    : the JSGeneratorObject to resume
+  //  -- rdx    : the resume mode (tagged)
+  //  -- rsp[0] : return address
+  // -----------------------------------
+  __ AssertAsyncGeneratorObject(rbx);
+  Generate_ResumeGenerator(masm, ResumeGeneratorType::kAwait);
+}
+
 static void LeaveInterpreterFrame(MacroAssembler* masm, Register scratch1,
                                   Register scratch2) {
   Register args_count = scratch1;
   Register return_pc = scratch2;
 
   // Get the arguments + receiver count.
   __ movp(args_count,
           Operand(rbp, InterpreterFrameConstants::kBytecodeArrayFromFp));
   __ movl(args_count,
           FieldOperand(args_count, BytecodeArray::kParameterSizeOffset));
@@ skipping 2474 matching lines @@
 void Builtins::Generate_InterpreterOnStackReplacement(MacroAssembler* masm) {
   Generate_OnStackReplacementHelper(masm, true);
 }
 
 #undef __
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_X64