A64: Synchronize with r15358.

src/globals.h

Index: src/globals.h
diff --git a/src/globals.h b/src/globals.h
index b36b64cb956cf7a582fdb2190255e8752725fc6b..c7f359874b4f857b11296dd8779d2deaf87d6aeb 100644
--- a/src/globals.h
+++ b/src/globals.h
@@ -162,6 +162,21 @@ namespace internal {
 #endif
 #endif
 
+// Determine architecture endiannes (we only support little-endian).
+#if defined(V8_TARGET_ARCH_IA32)
+#define V8_TARGET_LITTLE_ENDIAN 1
+#elif defined(V8_TARGET_ARCH_X64)
+#define V8_TARGET_LITTLE_ENDIAN 1
+#elif defined(V8_TARGET_ARCH_ARM)
+#define V8_TARGET_LITTLE_ENDIAN 1
+#elif defined(V8_TARGET_ARCH_A64)
+#define V8_TARGET_LITTLE_ENDIAN 1
+#elif defined(V8_TARGET_ARCH_MIPS)
+#define V8_TARGET_LITTLE_ENDIAN 1
+#else
+#error Unknown target architecture endiannes
+#endif
+
 // Support for alternative bool type. This is only enabled if the code is
 // compiled with USE_MYBOOL defined. This catches some nasty type bugs.
 // For instance, 'bool b = "false";' results in b == true! This is a hidden
@@ -413,6 +428,18 @@ enum LanguageMode {
 };
 
 
+// A simple Maybe type, that can be passed by value.
+template<class T>
+struct Maybe {
+  Maybe() : has_value(false) {}
+  explicit Maybe(T t) : has_value(true), value(t) {}
+  Maybe(bool has, T t) : has_value(has), value(t) {}
+
+  bool has_value;
+  T value;
+};
+
+
 // The Strict Mode (ECMA-262 5th edition, 4.2.2).
 //
 // This flag is used in the backend to represent the language mode. So far