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

src/builtins/builtins-sharedarraybuffer.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/base/macros.h"
 #include "src/base/platform/mutex.h"
 #include "src/base/platform/time.h"
 #include "src/builtins/builtins-utils.h"
 #include "src/builtins/builtins.h"
 #include "src/code-factory.h"
@@ skipping 67 matching lines @@
   STATIC_ASSERT(FIXED_UINT32_ARRAY_TYPE < FIXED_FLOAT32_ARRAY_TYPE);
   a->Branch(a->Int32LessThan(elements_instance_type,
                              a->Int32Constant(FIXED_FLOAT32_ARRAY_TYPE)),
             &not_float_or_clamped, &is_float_or_clamped);
   a->Bind(&is_float_or_clamped);
   a->Goto(&invalid);
 
   a->Bind(&invalid);
   a->CallRuntime(Runtime::kThrowNotIntegerSharedTypedArrayError, context,
                  tagged);
-  a->Return(a->UndefinedConstant());
+  a->Unreachable();
 
   a->Bind(&not_float_or_clamped);
   *out_instance_type = elements_instance_type;
 
   Node* backing_store =
       a->LoadObjectField(array_buffer, JSArrayBuffer::kBackingStoreOffset);
   Node* byte_offset = a->ChangeUint32ToWord(a->TruncateTaggedToWord32(
       context,
       a->LoadObjectField(tagged, JSArrayBufferView::kByteOffsetOffset)));
   *out_backing_store =
@@ skipping 30 matching lines @@
     a->Branch(a->Float64Equal(number_index_value, test_index),
               &if_indexesareequal, &if_indexesarenotequal);
 
     a->Bind(&if_indexesareequal);
     {
       var_result.Bind(access_index);
       a->Goto(&done);
     }
 
     a->Bind(&if_indexesarenotequal);
-    a->Return(
-        a->CallRuntime(Runtime::kThrowInvalidAtomicAccessIndexError, context));
+    a->CallRuntime(Runtime::kThrowInvalidAtomicAccessIndexError, context);
+    a->Unreachable();
   }
 
   a->Bind(&done);
   return var_result.value();
 }
 
 void ValidateAtomicIndex(CodeStubAssembler* a, compiler::Node* index_word,
                          compiler::Node* array_length_word,
                          compiler::Node* context) {
   using compiler::Node;
   // Check if the index is in bounds. If not, throw RangeError.
   CodeStubAssembler::Label if_inbounds(a), if_notinbounds(a);
   // TODO(jkummerow): Use unsigned comparison instead of "i<0 || i>length".
   a->Branch(
       a->Word32Or(a->Int32LessThan(index_word, a->Int32Constant(0)),
                   a->Int32GreaterThanOrEqual(index_word, array_length_word)),
       &if_notinbounds, &if_inbounds);
   a->Bind(&if_notinbounds);
-  a->Return(
-      a->CallRuntime(Runtime::kThrowInvalidAtomicAccessIndexError, context));
+  a->CallRuntime(Runtime::kThrowInvalidAtomicAccessIndexError, context);
+  a->Unreachable();
   a->Bind(&if_inbounds);
 }
 
 }  // anonymous namespace
 
 void Builtins::Generate_AtomicsLoad(compiler::CodeAssemblerState* state) {
   using compiler::Node;
   CodeStubAssembler a(state);
   Node* array = a.Parameter(1);
   Node* index = a.Parameter(2);
@@ skipping 822 matching lines @@
     default:
       break;
   }
 
   UNREACHABLE();
   return isolate->heap()->undefined_value();
 }
 
 }  // namespace internal
 }  // namespace v8