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1//===-- Shared memory RPC client / server interface -------------*- C++ -*-===//2//3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.4// See https://llvm.org/LICENSE.txt for license information.5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception6//7//===----------------------------------------------------------------------===//8//9// This file implements a remote procedure call mechanism to communicate between10// heterogeneous devices that can share an address space atomically. We provide11// a client and a server to facilitate the remote call. The client makes request12// to the server using a shared communication channel. We use separate atomic13// signals to indicate which side, the client or the server is in ownership of14// the buffer.15//16//===----------------------------------------------------------------------===//17 18#ifndef LLVM_LIBC_SHARED_RPC_H19#define LLVM_LIBC_SHARED_RPC_H20 21#include "rpc_util.h"22 23namespace rpc {24 25/// Use scoped atomic variants if they are available for the target.26#if !__has_builtin(__scoped_atomic_load_n)27#define __scoped_atomic_load_n(src, ord, scp) __atomic_load_n(src, ord)28#define __scoped_atomic_store_n(dst, src, ord, scp)                            \29  __atomic_store_n(dst, src, ord)30#define __scoped_atomic_fetch_or(src, val, ord, scp)                           \31  __atomic_fetch_or(src, val, ord)32#define __scoped_atomic_fetch_and(src, val, ord, scp)                          \33  __atomic_fetch_and(src, val, ord)34#endif35#if !__has_builtin(__scoped_atomic_thread_fence)36#define __scoped_atomic_thread_fence(ord, scp) __atomic_thread_fence(ord)37#endif38 39/// Generic codes that can be used whem implementing the server.40enum Status {41  RPC_SUCCESS = 0x0,42  RPC_ERROR = 0x1000,43  RPC_UNHANDLED_OPCODE = 0x1001,44};45 46/// A fixed size channel used to communicate between the RPC client and server.47struct Buffer {48  uint64_t data[8];49};50static_assert(sizeof(Buffer) == 64, "Buffer size mismatch");51 52/// The information associated with a packet. This indicates which operations to53/// perform and which threads are active in the slots.54struct Header {55  uint64_t mask;56  uint32_t opcode;57};58 59/// The maximum number of parallel ports that the RPC interface can support.60constexpr static uint64_t MAX_PORT_COUNT = 4096;61 62/// A common process used to synchronize communication between a client and a63/// server. The process contains a read-only inbox and a write-only outbox used64/// for signaling ownership of the shared buffer between both sides. We assign65/// ownership of the buffer to the client if the inbox and outbox bits match,66/// otherwise it is owned by the server.67///68/// This process is designed to allow the client and the server to exchange data69/// using a fixed size packet in a mostly arbitrary order using the 'send' and70/// 'recv' operations. The following restrictions to this scheme apply:71///   - The client will always start with a 'send' operation.72///   - The server will always start with a 'recv' operation.73///   - Every 'send' or 'recv' call is mirrored by the other process.74template <bool Invert> struct Process {75  RPC_ATTRS Process() = default;76  RPC_ATTRS Process(const Process &) = delete;77  RPC_ATTRS Process &operator=(const Process &) = delete;78  RPC_ATTRS Process(Process &&) = default;79  RPC_ATTRS Process &operator=(Process &&) = default;80  RPC_ATTRS ~Process() = default;81 82  const uint32_t port_count = 0;83  const uint32_t *const inbox = nullptr;84  uint32_t *const outbox = nullptr;85  Header *const header = nullptr;86  Buffer *const packet = nullptr;87 88  static constexpr uint64_t NUM_BITS_IN_WORD = sizeof(uint32_t) * 8;89  uint32_t lock[MAX_PORT_COUNT / NUM_BITS_IN_WORD] = {0};90 91  RPC_ATTRS Process(uint32_t port_count, void *buffer)92      : port_count(port_count), inbox(reinterpret_cast<uint32_t *>(93                                    advance(buffer, inbox_offset(port_count)))),94        outbox(reinterpret_cast<uint32_t *>(95            advance(buffer, outbox_offset(port_count)))),96        header(reinterpret_cast<Header *>(97            advance(buffer, header_offset(port_count)))),98        packet(reinterpret_cast<Buffer *>(99            advance(buffer, buffer_offset(port_count)))) {}100 101  /// Allocate a memory buffer sufficient to store the following equivalent102  /// representation in memory.103  ///104  /// struct Equivalent {105  ///   Atomic<uint32_t> primary[port_count];106  ///   Atomic<uint32_t> secondary[port_count];107  ///   Header header[port_count];108  ///   Buffer packet[port_count][lane_size];109  /// };110  RPC_ATTRS static constexpr uint64_t allocation_size(uint32_t port_count,111                                                      uint32_t lane_size) {112    return buffer_offset(port_count) + buffer_bytes(port_count, lane_size);113  }114 115  /// Retrieve the inbox state from memory shared between processes.116  RPC_ATTRS uint32_t load_inbox(uint64_t lane_mask, uint32_t index) const {117    return rpc::broadcast_value(118        lane_mask, __scoped_atomic_load_n(&inbox[index], __ATOMIC_RELAXED,119                                          __MEMORY_SCOPE_SYSTEM));120  }121 122  /// Retrieve the outbox state from memory shared between processes.123  RPC_ATTRS uint32_t load_outbox(uint64_t lane_mask, uint32_t index) const {124    return rpc::broadcast_value(125        lane_mask, __scoped_atomic_load_n(&outbox[index], __ATOMIC_RELAXED,126                                          __MEMORY_SCOPE_SYSTEM));127  }128 129  /// Signal to the other process that this one is finished with the buffer.130  /// Equivalent to loading outbox followed by store of the inverted value131  /// The outbox is write only by this warp and tracking the value locally is132  /// cheaper than calling load_outbox to get the value to store.133  RPC_ATTRS uint32_t invert_outbox(uint32_t index, uint32_t current_outbox) {134    uint32_t inverted_outbox = !current_outbox;135    __scoped_atomic_thread_fence(__ATOMIC_RELEASE, __MEMORY_SCOPE_SYSTEM);136    __scoped_atomic_store_n(&outbox[index], inverted_outbox, __ATOMIC_RELAXED,137                            __MEMORY_SCOPE_SYSTEM);138    return inverted_outbox;139  }140 141  // Given the current outbox and inbox values, wait until the inbox changes142  // to indicate that this thread owns the buffer element.143  RPC_ATTRS void wait_for_ownership(uint64_t lane_mask, uint32_t index,144                                    uint32_t outbox, uint32_t in) {145    while (buffer_unavailable(in, outbox)) {146      sleep_briefly();147      in = load_inbox(lane_mask, index);148    }149    __scoped_atomic_thread_fence(__ATOMIC_ACQUIRE, __MEMORY_SCOPE_SYSTEM);150  }151 152  /// The packet is a linearly allocated array of buffers used to communicate153  /// with the other process. This function returns the appropriate slot in this154  /// array such that the process can operate on an entire warp or wavefront.155  RPC_ATTRS Buffer *get_packet(uint32_t index, uint32_t lane_size) {156    return &packet[index * lane_size];157  }158 159  /// Determines if this process needs to wait for ownership of the buffer. We160  /// invert the condition on one of the processes to indicate that if one161  /// process owns the buffer then the other does not.162  RPC_ATTRS static bool buffer_unavailable(uint32_t in, uint32_t out) {163    bool cond = in != out;164    return Invert ? !cond : cond;165  }166 167  /// Attempt to claim the lock at index. Return true on lock taken.168  /// lane_mask is a bitmap of the threads in the warp that would hold the169  /// single lock on success, e.g. the result of rpc::get_lane_mask()170  /// The lock is held when the n-th bit of the lock bitfield is set.171  RPC_ATTRS bool try_lock(uint64_t lane_mask, uint32_t index) {172    // On amdgpu, test and set to the nth lock bit and a sync_lane would suffice173    // On volta, need to handle differences between the threads running and174    // the threads that were detected in the previous call to get_lane_mask()175    //176    // All threads in lane_mask try to claim the lock. At most one can succeed.177    // There may be threads active which are not in lane mask which must not178    // succeed in taking the lock, as otherwise it will leak. This is handled179    // by making threads which are not in lane_mask or with 0, a no-op.180    uint32_t id = rpc::get_lane_id();181    bool id_in_lane_mask = lane_mask & (1ul << id);182 183    // All threads in the warp call fetch_or. Possibly at the same time.184    bool before = set_nth(lock, index, id_in_lane_mask);185    uint64_t packed = rpc::ballot(lane_mask, before);186 187    // If every bit set in lane_mask is also set in packed, every single thread188    // in the warp failed to get the lock. Ballot returns unset for threads not189    // in the lane mask.190    //191    // Cases, per thread:192    // mask==0 -> unspecified before, discarded by ballot -> 0193    // mask==1 and before==0 (success), set zero by ballot -> 0194    // mask==1 and before==1 (failure), set one by ballot -> 1195    //196    // mask != packed implies at least one of the threads got the lock197    // atomic semantics of fetch_or mean at most one of the threads for the lock198 199    // If holding the lock then the caller can load values knowing said loads200    // won't move past the lock. No such guarantee is needed if the lock acquire201    // failed. This conditional branch is expected to fold in the caller after202    // inlining the current function.203    bool holding_lock = lane_mask != packed;204    if (holding_lock)205      __scoped_atomic_thread_fence(__ATOMIC_ACQUIRE, __MEMORY_SCOPE_DEVICE);206    return holding_lock;207  }208 209  /// Unlock the lock at index. We need a lane sync to keep this function210  /// convergent, otherwise the compiler will sink the store and deadlock.211  RPC_ATTRS void unlock(uint64_t lane_mask, uint32_t index) {212    // Do not move any writes past the unlock.213    __scoped_atomic_thread_fence(__ATOMIC_RELEASE, __MEMORY_SCOPE_DEVICE);214 215    // Use exactly one thread to clear the nth bit in the lock array Must216    // restrict to a single thread to avoid one thread dropping the lock, then217    // an unrelated warp claiming the lock, then a second thread in this warp218    // dropping the lock again.219    clear_nth(lock, index, rpc::is_first_lane(lane_mask));220    rpc::sync_lane(lane_mask);221  }222 223  /// Number of bytes to allocate for an inbox or outbox.224  RPC_ATTRS static constexpr uint64_t mailbox_bytes(uint32_t port_count) {225    return port_count * sizeof(uint32_t);226  }227 228  /// Number of bytes to allocate for the buffer containing the packets.229  RPC_ATTRS static constexpr uint64_t buffer_bytes(uint32_t port_count,230                                                   uint32_t lane_size) {231    return port_count * lane_size * sizeof(Buffer);232  }233 234  /// Offset of the inbox in memory. This is the same as the outbox if inverted.235  RPC_ATTRS static constexpr uint64_t inbox_offset(uint32_t port_count) {236    return Invert ? mailbox_bytes(port_count) : 0;237  }238 239  /// Offset of the outbox in memory. This is the same as the inbox if inverted.240  RPC_ATTRS static constexpr uint64_t outbox_offset(uint32_t port_count) {241    return Invert ? 0 : mailbox_bytes(port_count);242  }243 244  /// Offset of the buffer containing the packets after the inbox and outbox.245  RPC_ATTRS static constexpr uint64_t header_offset(uint32_t port_count) {246    return align_up(2 * mailbox_bytes(port_count), alignof(Header));247  }248 249  /// Offset of the buffer containing the packets after the inbox and outbox.250  RPC_ATTRS static constexpr uint64_t buffer_offset(uint32_t port_count) {251    return align_up(header_offset(port_count) + port_count * sizeof(Header),252                    alignof(Buffer));253  }254 255  /// Conditionally set the n-th bit in the atomic bitfield.256  RPC_ATTRS static constexpr uint32_t set_nth(uint32_t *bits, uint32_t index,257                                              bool cond) {258    uint32_t slot = index / NUM_BITS_IN_WORD;259    uint32_t bit = index % NUM_BITS_IN_WORD;260    return __scoped_atomic_fetch_or(&bits[slot],261                                    static_cast<uint32_t>(cond) << bit,262                                    __ATOMIC_RELAXED, __MEMORY_SCOPE_DEVICE) &263           (1u << bit);264  }265 266  /// Conditionally clear the n-th bit in the atomic bitfield.267  RPC_ATTRS static constexpr uint32_t clear_nth(uint32_t *bits, uint32_t index,268                                                bool cond) {269    uint32_t slot = index / NUM_BITS_IN_WORD;270    uint32_t bit = index % NUM_BITS_IN_WORD;271    return __scoped_atomic_fetch_and(&bits[slot],272                                     ~0u ^ (static_cast<uint32_t>(cond) << bit),273                                     __ATOMIC_RELAXED, __MEMORY_SCOPE_DEVICE) &274           (1u << bit);275  }276};277 278/// Invokes a function across every active buffer across the total lane size.279template <typename F>280RPC_ATTRS static void invoke_rpc(F &&fn, uint32_t lane_size, uint64_t lane_mask,281                                 Buffer *slot) {282  if constexpr (is_process_gpu()) {283    fn(&slot[rpc::get_lane_id()], rpc::get_lane_id());284  } else {285    for (uint32_t i = 0; i < lane_size; i += rpc::get_num_lanes())286      if (lane_mask & (1ul << i))287        fn(&slot[i], i);288  }289}290 291/// The port provides the interface to communicate between the multiple292/// processes. A port is conceptually an index into the memory provided by the293/// underlying process that is guarded by a lock bit.294template <bool T> struct Port {295  RPC_ATTRS Port(Process<T> &process, uint64_t lane_mask, uint32_t lane_size,296                 uint32_t index, uint32_t out)297      : process(process), lane_mask(lane_mask), lane_size(lane_size),298        index(index), out(out), receive(false), owns_buffer(true) {}299  RPC_ATTRS ~Port() = default;300 301private:302  RPC_ATTRS Port(const Port &) = delete;303  RPC_ATTRS Port &operator=(const Port &) = delete;304  RPC_ATTRS Port(Port &&) = default;305  RPC_ATTRS Port &operator=(Port &&) = default;306 307  friend struct Client;308  friend struct Server;309  friend class rpc::optional<Port<T>>;310 311public:312  template <typename U> RPC_ATTRS void recv(U use);313  template <typename F> RPC_ATTRS void send(F fill);314  template <typename F, typename U> RPC_ATTRS void send_and_recv(F fill, U use);315  template <typename W> RPC_ATTRS void recv_and_send(W work);316  RPC_ATTRS void send_n(const void *const *src, uint64_t *size);317  RPC_ATTRS void send_n(const void *src, uint64_t size);318  template <typename A>319  RPC_ATTRS void recv_n(void **dst, uint64_t *size, A &&alloc);320 321  RPC_ATTRS uint32_t get_opcode() const { return process.header[index].opcode; }322 323  RPC_ATTRS uint32_t get_index() const { return index; }324 325  RPC_ATTRS void close() {326    // Wait for all lanes to finish using the port.327    rpc::sync_lane(lane_mask);328 329    // The server is passive, if it own the buffer when it closes we need to330    // give ownership back to the client.331    if (owns_buffer && T)332      out = process.invert_outbox(index, out);333    process.unlock(lane_mask, index);334  }335 336private:337  Process<T> &process;338  uint64_t lane_mask;339  uint32_t lane_size;340  uint32_t index;341  uint32_t out;342  bool receive;343  bool owns_buffer;344};345 346/// The RPC client used to make requests to the server.347struct Client {348  RPC_ATTRS Client() = default;349  RPC_ATTRS Client(const Client &) = delete;350  RPC_ATTRS Client &operator=(const Client &) = delete;351  RPC_ATTRS ~Client() = default;352 353  RPC_ATTRS Client(uint32_t port_count, void *buffer)354      : process(port_count, buffer) {}355 356  using Port = rpc::Port<false>;357  template <uint32_t opcode> RPC_ATTRS Port open();358 359private:360  Process<false> process;361};362 363/// The RPC server used to respond to the client.364struct Server {365  RPC_ATTRS Server() = default;366  RPC_ATTRS Server(const Server &) = delete;367  RPC_ATTRS Server &operator=(const Server &) = delete;368  RPC_ATTRS ~Server() = default;369 370  RPC_ATTRS Server(uint32_t port_count, void *buffer)371      : process(port_count, buffer) {}372 373  using Port = rpc::Port<true>;374  RPC_ATTRS rpc::optional<Port> try_open(uint32_t lane_size,375                                         uint32_t start = 0);376  RPC_ATTRS Port open(uint32_t lane_size);377 378  RPC_ATTRS static constexpr uint64_t allocation_size(uint32_t lane_size,379                                                      uint32_t port_count) {380    return Process<true>::allocation_size(port_count, lane_size);381  }382 383private:384  Process<true> process;385};386 387/// Applies \p fill to the shared buffer and initiates a send operation.388template <bool T> template <typename F> RPC_ATTRS void Port<T>::send(F fill) {389  uint32_t in = owns_buffer ? out ^ T : process.load_inbox(lane_mask, index);390 391  // We need to wait until we own the buffer before sending.392  process.wait_for_ownership(lane_mask, index, out, in);393 394  // Apply the \p fill function to initialize the buffer and release the memory.395  invoke_rpc(fill, lane_size, process.header[index].mask,396             process.get_packet(index, lane_size));397  out = process.invert_outbox(index, out);398  owns_buffer = false;399  receive = false;400}401 402/// Applies \p use to the shared buffer and acknowledges the send.403template <bool T> template <typename U> RPC_ATTRS void Port<T>::recv(U use) {404  // We only exchange ownership of the buffer during a receive if we are waiting405  // for a previous receive to finish.406  if (receive) {407    out = process.invert_outbox(index, out);408    owns_buffer = false;409  }410 411  uint32_t in = owns_buffer ? out ^ T : process.load_inbox(lane_mask, index);412 413  // We need to wait until we own the buffer before receiving.414  process.wait_for_ownership(lane_mask, index, out, in);415 416  // Apply the \p use function to read the memory out of the buffer.417  invoke_rpc(use, lane_size, process.header[index].mask,418             process.get_packet(index, lane_size));419  receive = true;420  owns_buffer = true;421}422 423/// Combines a send and receive into a single function.424template <bool T>425template <typename F, typename U>426RPC_ATTRS void Port<T>::send_and_recv(F fill, U use) {427  send(fill);428  recv(use);429}430 431/// Combines a receive and send operation into a single function. The \p work432/// function modifies the buffer in-place and the send is only used to initiate433/// the copy back.434template <bool T>435template <typename W>436RPC_ATTRS void Port<T>::recv_and_send(W work) {437  recv(work);438  send([](Buffer *, uint32_t) { /* no-op */ });439}440 441/// Helper routine to simplify the interface when sending from the GPU using442/// thread private pointers to the underlying value.443template <bool T>444RPC_ATTRS void Port<T>::send_n(const void *src, uint64_t size) {445  const void **src_ptr = &src;446  uint64_t *size_ptr = &size;447  send_n(src_ptr, size_ptr);448}449 450/// Sends an arbitrarily sized data buffer \p src across the shared channel in451/// multiples of the packet length.452template <bool T>453RPC_ATTRS void Port<T>::send_n(const void *const *src, uint64_t *size) {454  uint64_t num_sends = 0;455  send([&](Buffer *buffer, uint32_t id) {456    reinterpret_cast<uint64_t *>(buffer->data)[0] = lane_value(size, id);457    num_sends = is_process_gpu() ? lane_value(size, id)458                                 : rpc::max(lane_value(size, id), num_sends);459    uint64_t len =460        lane_value(size, id) > sizeof(Buffer::data) - sizeof(uint64_t)461            ? sizeof(Buffer::data) - sizeof(uint64_t)462            : lane_value(size, id);463    rpc_memcpy(&buffer->data[1], lane_value(src, id), len);464  });465  uint64_t idx = sizeof(Buffer::data) - sizeof(uint64_t);466  uint64_t mask = process.header[index].mask;467  while (rpc::ballot(mask, idx < num_sends)) {468    send([=](Buffer *buffer, uint32_t id) {469      uint64_t len = lane_value(size, id) - idx > sizeof(Buffer::data)470                         ? sizeof(Buffer::data)471                         : lane_value(size, id) - idx;472      if (idx < lane_value(size, id))473        rpc_memcpy(buffer->data, advance(lane_value(src, id), idx), len);474    });475    idx += sizeof(Buffer::data);476  }477}478 479/// Receives an arbitrarily sized data buffer across the shared channel in480/// multiples of the packet length. The \p alloc function is called with the481/// size of the data so that we can initialize the size of the \p dst buffer.482template <bool T>483template <typename A>484RPC_ATTRS void Port<T>::recv_n(void **dst, uint64_t *size, A &&alloc) {485  uint64_t num_recvs = 0;486  recv([&](Buffer *buffer, uint32_t id) {487    lane_value(size, id) = reinterpret_cast<uint64_t *>(buffer->data)[0];488    lane_value(dst, id) =489        reinterpret_cast<uint8_t *>(alloc(lane_value(size, id)));490    num_recvs = is_process_gpu() ? lane_value(size, id)491                                 : rpc::max(lane_value(size, id), num_recvs);492    uint64_t len =493        lane_value(size, id) > sizeof(Buffer::data) - sizeof(uint64_t)494            ? sizeof(Buffer::data) - sizeof(uint64_t)495            : lane_value(size, id);496    rpc_memcpy(lane_value(dst, id), &buffer->data[1], len);497  });498  uint64_t idx = sizeof(Buffer::data) - sizeof(uint64_t);499  uint64_t mask = process.header[index].mask;500  while (rpc::ballot(mask, idx < num_recvs)) {501    recv([=](Buffer *buffer, uint32_t id) {502      uint64_t len = lane_value(size, id) - idx > sizeof(Buffer::data)503                         ? sizeof(Buffer::data)504                         : lane_value(size, id) - idx;505      if (idx < lane_value(size, id))506        rpc_memcpy(advance(lane_value(dst, id), idx), buffer->data, len);507    });508    idx += sizeof(Buffer::data);509  }510}511 512/// Continually attempts to open a port to use as the client. The client can513/// only open a port if we find an index that is in a valid sending state. That514/// is, there are send operations pending that haven't been serviced on this515/// port. Each port instance uses an associated \p opcode to tell the server516/// what to do. The Client interface provides the appropriate lane size to the517/// port using the platform's returned value.518template <uint32_t opcode> RPC_ATTRS Client::Port Client::open() {519  // Repeatedly perform a naive linear scan for a port that can be opened to520  // send data.521  for (uint32_t index = 0;; ++index) {522    // Start from the beginning if we run out of ports to check.523    if (index >= process.port_count)524      index = 0;525 526    // Attempt to acquire the lock on this index.527    uint64_t lane_mask = rpc::get_lane_mask();528    if (!process.try_lock(lane_mask, index))529      continue;530 531    uint32_t in = process.load_inbox(lane_mask, index);532    uint32_t out = process.load_outbox(lane_mask, index);533 534    // Once we acquire the index we need to check if we are in a valid sending535    // state.536    if (process.buffer_unavailable(in, out)) {537      process.unlock(lane_mask, index);538      continue;539    }540 541    if (rpc::is_first_lane(lane_mask)) {542      process.header[index].opcode = opcode;543      process.header[index].mask = lane_mask;544    }545    rpc::sync_lane(lane_mask);546    return Port(process, lane_mask, rpc::get_num_lanes(), index, out);547  }548}549 550/// Attempts to open a port to use as the server. The server can only open a551/// port if it has a pending receive operation552RPC_ATTRS rpc::optional<typename Server::Port>553Server::try_open(uint32_t lane_size, uint32_t start) {554  if (rpc::get_lane_id() >= lane_size)555    return rpc::nullopt;556 557  // Perform a naive linear scan for a port that has a pending request.558  for (uint32_t index = start; index < process.port_count; ++index) {559    uint64_t lane_mask = rpc::get_lane_mask();560    uint32_t in = process.load_inbox(lane_mask, index);561    uint32_t out = process.load_outbox(lane_mask, index);562 563    // The server is passive, if there is no work pending don't bother564    // opening a port.565    if (process.buffer_unavailable(in, out))566      continue;567 568    // Attempt to acquire the lock on this index.569    if (!process.try_lock(lane_mask, index))570      continue;571 572    in = process.load_inbox(lane_mask, index);573    out = process.load_outbox(lane_mask, index);574 575    if (process.buffer_unavailable(in, out)) {576      process.unlock(lane_mask, index);577      continue;578    }579 580    return Port(process, lane_mask, lane_size, index, out);581  }582  return rpc::nullopt;583}584 585RPC_ATTRS Server::Port Server::open(uint32_t lane_size) {586  for (;;) {587    if (rpc::optional<Server::Port> p = try_open(lane_size))588      return rpc::move(p.value());589    sleep_briefly();590  }591}592 593#undef RPC_ATTRS594#if !__has_builtin(__scoped_atomic_load_n)595#undef __scoped_atomic_load_n596#undef __scoped_atomic_store_n597#undef __scoped_atomic_fetch_or598#undef __scoped_atomic_fetch_and599#endif600#if !__has_builtin(__scoped_atomic_thread_fence)601#undef __scoped_atomic_thread_fence602#endif603 604} // namespace rpc605 606#endif // LLVM_LIBC_SHARED_RPC_H607