[libc] Make the RPC interfaces move only

[jhuber6]

Summary

This patch uses the changed interface in D149972 to make these classes
move-only. The Port class could be further refined to be
construct-only in a future patch, but for now this makes it more
difficult to misuse the interface.

Depends on D149972

libc/src/__support/RPC/rpc.h

 /// using this process are as follows:
 ///   - The client will always start with a 'send' operation
 ///   - The server will always start with a 'recv' operation
 ///   - For every 'send' / 'recv' call on one side of the process there is a
 ///     mirrored 'recv' / 'send' call.
 ///
 template <bool InvertInbox> struct Process {
   LIBC_INLINE Process() = default;
-  LIBC_INLINE Process(const Process &) = default;
-  LIBC_INLINE Process &operator=(const Process &) = default;
+  LIBC_INLINE Process(const Process &) = delete;
+  LIBC_INLINE Process &operator=(const Process &) = delete;
+  LIBC_INLINE Process(Process &&) = default;
+  LIBC_INLINE Process &operator=(Process &&) = default;
   LIBC_INLINE ~Process() = default;
 
   uint64_t port_count;
   uint32_t lane_size;
   cpp::Atomic<uint32_t> *lock;
   cpp::Atomic<uint32_t> *inbox;
   cpp::Atomic<uint32_t> *outbox;
   Packet *packet;

 /// The port provides the interface to communicate between the multiple
 /// processes. A port is conceptually an index into the memory provided by the
 /// underlying process that is guarded by a lock bit.
 template <bool T> struct Port {
   // TODO: This should be move-only.
   LIBC_INLINE Port(Process<T> &process, uint64_t lane_mask, uint64_t index,
                    uint32_t out)
       : process(process), lane_mask(lane_mask), index(index), out(out) {}
-  LIBC_INLINE Port(const Port &) = default;
+  LIBC_INLINE Port(const Port &) = delete;
   LIBC_INLINE Port &operator=(const Port &) = delete;
+  LIBC_INLINE Port(Port &&) = default;
+  LIBC_INLINE Port &operator=(Port &&) = default;
   LIBC_INLINE ~Port() = default;
 
   template <typename U> LIBC_INLINE void recv(U use);
   template <typename F> LIBC_INLINE void send(F fill);
   template <typename F, typename U>
   LIBC_INLINE void send_and_recv(F fill, U use);
   template <typename W> LIBC_INLINE void recv_and_send(W work);
   LIBC_INLINE void send_n(const void *src, uint64_t size);
private:
   uint64_t lane_mask;
   uint64_t index;
   uint32_t out;
 };
 
 /// The RPC client used to make requests to the server.
 struct Client : public Process<false> {
   LIBC_INLINE Client() = default;
-  LIBC_INLINE Client(const Client &) = default;
-  LIBC_INLINE Client &operator=(const Client &) = default;
+  LIBC_INLINE Client(const Client &) = delete;
+  LIBC_INLINE Client &operator=(const Client &) = delete;
   LIBC_INLINE ~Client() = default;
 
   using Port = rpc::Port<false>;
   LIBC_INLINE cpp::optional<Port> try_open(uint16_t opcode);
   LIBC_INLINE Port open(uint16_t opcode);
 };
 
 /// The RPC server used to respond to the client.
 struct Server : public Process<true> {
   LIBC_INLINE Server() = default;
-  LIBC_INLINE Server(const Server &) = default;
-  LIBC_INLINE Server &operator=(const Server &) = default;
+  LIBC_INLINE Server(const Server &) = delete;
+  LIBC_INLINE Server &operator=(const Server &) = delete;
   LIBC_INLINE ~Server() = default;
 
   using Port = rpc::Port<true>;
   LIBC_INLINE cpp::optional<Port> try_open();
   LIBC_INLINE Port open();
 };
 
 /// Applies \p fill to the shared buffer and initiates a send operation.
for (uint64_t index = 0; index < port_count; ++index) {
     return Port(*this, lane_mask, index, out);
   }
   return cpp::nullopt;
 }
 
 LIBC_INLINE Client::Port Client::open(uint16_t opcode) {
   for (;;) {
     if (cpp::optional<Client::Port> p = try_open(opcode))
-      return p.value();
+      return cpp::move(p.value());
     sleep_briefly();
   }
 }
 
 /// Attempts to open a port to use as the server. The server can only open a
 /// port if it has a pending receive operation
 [[clang::convergent]] LIBC_INLINE cpp::optional<Server::Port>
 Server::try_open() {
for (uint64_t index = 0; index < port_count; ++index) {
     return Port(*this, lane_mask, index, out);
   }
   return cpp::nullopt;
 }
 
 LIBC_INLINE Server::Port Server::open() {
   for (;;) {
     if (cpp::optional<Server::Port> p = try_open())
-      return p.value();
+      return cpp::move(p.value());
     sleep_briefly();
   }
 }
 
 } // namespace rpc
 } // namespace __llvm_libc
 
 #endif