[csa] Add Unreachable() and use it after throw sites

src/builtins/builtins-date.cc

 // 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.
 
 #include "src/builtins/builtins-utils.h"
 #include "src/builtins/builtins.h"
 #include "src/code-factory.h"
 #include "src/code-stub-assembler.h"
 #include "src/dateparser-inl.h"
 
@@ skipping 927 matching lines @@
         ExternalReference::get_date_field_function(assembler->isolate()));
     Node* result = assembler->CallCFunction2(
         MachineType::AnyTagged(), MachineType::AnyTagged(),
         MachineType::AnyTagged(), function, receiver, field_index_smi);
     assembler->Return(result);
   }
 
   // Raise a TypeError if the receiver is not a date.
   assembler->Bind(&receiver_not_date);
   {
-    Node* result = assembler->CallRuntime(Runtime::kThrowNotDateError, context);
-    assembler->Return(result);
+    assembler->CallRuntime(Runtime::kThrowNotDateError, context);
+    assembler->Unreachable();
   }
 }
 
 }  // namespace
 
 // static
 void Builtins::Generate_DatePrototypeGetDate(
     compiler::CodeAssemblerState* state) {
   CodeStubAssembler assembler(state);
   Generate_DatePrototype_GetField(&assembler, JSDate::kDay);
@@ skipping 185 matching lines @@
   {
     Callable callable = CodeFactory::OrdinaryToPrimitive(
         assembler.isolate(), OrdinaryToPrimitiveHint::kString);
     Node* result = assembler.CallStub(callable, context, receiver);
     assembler.Return(result);
   }
 
   // Raise a TypeError if the {hint} is invalid.
   assembler.Bind(&hint_is_invalid);
   {
-    Node* result =
-        assembler.CallRuntime(Runtime::kThrowInvalidHint, context, hint);
-    assembler.Return(result);
+    assembler.CallRuntime(Runtime::kThrowInvalidHint, context, hint);
+    assembler.Unreachable();
   }
 
   // Raise a TypeError if the {receiver} is not a JSReceiver instance.
   assembler.Bind(&receiver_is_invalid);
   {
-    Node* result = assembler.CallRuntime(
+    assembler.CallRuntime(
         Runtime::kThrowIncompatibleMethodReceiver, context,
         assembler.HeapConstant(assembler.factory()->NewStringFromAsciiChecked(
             "Date.prototype [ @@toPrimitive ]", TENURED)),
         receiver);
-    assembler.Return(result);
+    assembler.Unreachable();
   }
 }
 
 }  // namespace internal
 }  // namespace v8