s390: implement atomic exchange on TF

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/builtins/builtins-utils.h"
 #include "src/builtins/builtins.h"
 #include "src/code-factory.h"
 #include "src/code-stub-assembler.h"
 
 namespace v8 {
@@ skipping 266 matching lines @@
   Node* index_integer;
   Node* index_word32 =
       ConvertTaggedAtomicIndexToWord32(index, context, &index_integer);
   Node* array_length_word32 = TruncateTaggedToWord32(
       context, LoadObjectField(array, JSTypedArray::kLengthOffset));
   ValidateAtomicIndex(index_word32, array_length_word32, context);
 
   Node* value_integer = ToInteger(context, value);
 
 #if V8_TARGET_ARCH_MIPS || V8_TARGET_ARCH_MIPS64 || V8_TARGET_ARCH_PPC64 || \
-    V8_TARGET_ARCH_PPC || V8_TARGET_ARCH_S390 || V8_TARGET_ARCH_S390X
+    V8_TARGET_ARCH_PPC
   Return(CallRuntime(Runtime::kAtomicsExchange, context, array, index_integer,
                      value_integer));
 #else
   Node* index_word = ChangeUint32ToWord(index_word32);
 
   Node* value_word32 = TruncateTaggedToWord32(context, value_integer);
 
   Label i8(this), u8(this), i16(this), u16(this), i32(this), u32(this),
       other(this);
   int32_t case_values[] = {
@@ skipping 34 matching lines @@
 
   // This shouldn't happen, we've already validated the type.
   Bind(&other);
   Unreachable();
 #endif  // V8_TARGET_ARCH_MIPS || V8_TARGET_ARCH_MIPS64 || V8_TARGET_ARCH_PPC64
         // || V8_TARGET_ARCH_PPC || V8_TARGET_ARCH_S390 || V8_TARGET_ARCH_S390X
 }
 
 }  // namespace internal
 }  // namespace v8