Move generator-close on exception from the generator function to the GeneratorResume builtin.

src/interpreter/bytecode-generator.cc

Index: src/interpreter/bytecode-generator.cc
diff --git a/src/interpreter/bytecode-generator.cc b/src/interpreter/bytecode-generator.cc
index f2a5d74029bc8f33726b604f218f48c0da6530be..58f1a98a70bde78dfff489c1d11375f344ac5bba 100644
--- a/src/interpreter/bytecode-generator.cc
+++ b/src/interpreter/bytecode-generator.cc
@@ -981,13 +981,16 @@ void BytecodeGenerator::BuildGeneratorPrologue() {
 
   // This is a resume call. Restore the current context and the registers,
   // then perform state dispatch.
-  Register generator_context = register_allocator()->NewRegister();
-  builder()
-      ->CallRuntime(Runtime::kInlineGeneratorGetContext, generator_object_)
-      .PushContext(generator_context)
-      .RestoreGeneratorState(generator_object_)
-      .StoreAccumulatorInRegister(generator_state_)
-      .SwitchOnSmiNoFeedback(generator_jump_table_);
+  {
+    RegisterAllocationScope register_scope(this);
+    Register generator_context = register_allocator()->NewRegister();
+    builder()
+        ->CallRuntime(Runtime::kInlineGeneratorGetContext, generator_object_)
+        .PushContext(generator_context)
+        .RestoreGeneratorState(generator_object_)
+        .StoreAccumulatorInRegister(generator_state_)
+        .SwitchOnSmiNoFeedback(generator_jump_table_);
+  }
   // We fall through when the generator state is not in the jump table.
   // TODO(leszeks): Only generate this for debug builds.
   BuildAbort(BailoutReason::kInvalidJumpTableIndex);
@@ -2183,6 +2186,13 @@ void BytecodeGenerator::BuildReturn() {
   if (info()->literal()->feedback_vector_spec()->HasTypeProfileSlot()) {
     builder()->CollectTypeProfile(info()->literal()->return_position());
   }
+  if (IsGeneratorFunction(info()->literal()->kind())) {
+    Register result = register_allocator()->NewRegister();

[rmcilroy, 2017/06/05 10:02:58]

nit - add a comment that we need to close the generator before returning.

[Jarin, 2017/06/05 16:03:25]

Done.

+    builder()
+        ->StoreAccumulatorInRegister(result)
+        .CallRuntime(Runtime::kInlineGeneratorClose, generator_object_)
+        .LoadAccumulatorWithRegister(result);
+  }
   builder()->Return();
 }
 
@@ -2546,6 +2556,14 @@ void BytecodeGenerator::BuildGeneratorSuspend(Suspend* expr, Register generator,
         .LoadFalse()
         .StoreAccumulatorInRegister(args[2])
         .CallRuntime(Runtime::kInlineAsyncGeneratorResolve, args);
+  } else if (expr->IsNonInitialGeneratorYield()) {

[rmcilroy, 2017/06/05 10:02:58]

nit - let's put this above expr->IsNonInitialAsyncGeneratorYield() (since it's
the more general case)

[Jarin, 2017/06/05 16:03:24]

Done.

+    // GeneratorYield: Wrap the value into IteratorResult.
+    RegisterList args = register_allocator()->NewRegisterList(2);
+    builder()
+        ->MoveRegister(value, args[0])
+        .LoadFalse()
+        .StoreAccumulatorInRegister(args[1])
+        .CallRuntime(Runtime::kInlineCreateIterResultObject, args);
   } else {
     builder()->LoadAccumulatorWithRegister(value);
   }
@@ -2599,17 +2617,11 @@ void BytecodeGenerator::BuildGeneratorResume(
         .JumpIfTrue(ToBooleanMode::kAlreadyBoolean, &resume_with_throw);
     // Fall through for resuming with return.
 
+    builder()->LoadAccumulatorWithRegister(input);
     if (expr->is_async_generator()) {
       // Async generator methods will produce the iter result object.
-      builder()->LoadAccumulatorWithRegister(input);
       execution_control()->AsyncReturnAccumulator();
     } else {
-      RegisterList args = register_allocator()->NewRegisterList(2);
-      builder()
-          ->MoveRegister(input, args[0])
-          .LoadTrue()
-          .StoreAccumulatorInRegister(args[1])
-          .CallRuntime(Runtime::kInlineCreateIterResultObject, args);
       execution_control()->ReturnAccumulator();
     }