Implement WASM big-endian support

src/utils.h

Index: src/utils.h
diff --git a/src/utils.h b/src/utils.h
index 9b94a2feb1de6a7e9fcc8910ec3008e93f4a3bca..2acc95ef3c07f9a5a565c9fffae1c59db289a14c 100644
--- a/src/utils.h
+++ b/src/utils.h
@@ -1552,6 +1552,33 @@ static inline void WriteUnalignedUInt32(void* p, uint32_t value) {
   WriteUnalignedValue(p, value);
 }
 
+template <typename V>
+static inline V ReadLittleEndianValue(const void* p) {
+#if defined(V8_TARGET_LITTLE_ENDIAN)
+  return ReadUnalignedValue<V>(p);
+#elif defined(V8_TARGET_BIG_ENDIAN)
+  V ret = 0;
+  const byte* src = reinterpret_cast<const byte*>(p);
+  byte* dst = reinterpret_cast<byte*>(&ret);
+  for (size_t i = 0; i < sizeof(V); i++) {
+    dst[i] = src[sizeof(V) - i - 1];
+  }
+  return ret;
+#endif  // V8_TARGET_LITTLE_ENDIAN
+}
+
+template <typename V>
+static inline void WriteLittleEndianValue(void* p, V value) {
+#if defined(V8_TARGET_LITTLE_ENDIAN)
+  WriteUnalignedValue<V>(p, value);
+#elif defined(V8_TARGET_BIG_ENDIAN)
+  byte* src = reinterpret_cast<byte*>(&value);
+  byte* dst = reinterpret_cast<byte*>(p);
+  for (size_t i = 0; i < sizeof(V); i++) {
+    dst[i] = src[sizeof(V) - i - 1];
+  }
+#endif  // V8_TARGET_LITTLE_ENDIAN
+}
 }  // namespace internal
 }  // namespace v8