[libc] Implement the 'rename' function on the GPU

libc/config/gpu/entrypoints.txt

@@ -240,6 +240,7 @@ set(TARGET_LIBC_ENTRYPOINTS
     libc.src.stdio.putchar
     libc.src.stdio.puts
     libc.src.stdio.remove
+    libc.src.stdio.rename
     libc.src.stdio.stderr
     libc.src.stdio.stdin
     libc.src.stdio.stdout

libc/docs/gpu/support.rst

@@ -240,6 +240,7 @@ fputs          |check|    |check|
 fputc          |check|    |check|
 fwrite         |check|    |check|
 remove         |check|    |check|
+rename         |check|    |check|
 putc           |check|    |check|
 printf         |check|    |check|
 vprintf        |check|    |check|

libc/include/llvm-libc-types/rpc_opcodes_t.h

@@ -38,6 +38,7 @@ typedef enum {
   RPC_PRINTF_TO_STDERR_PACKED,
   RPC_PRINTF_TO_STREAM_PACKED,
   RPC_REMOVE,
+  RPC_RENAME,
   RPC_SYSTEM,
   RPC_LAST = 0xFFFF,
 } rpc_opcode_t;

libc/src/stdio/gpu/CMakeLists.txt

@@ -294,6 +294,17 @@ add_entrypoint_object(
     .vfprintf_utils
 )
 
+add_entrypoint_object(
+  rename
+  SRCS
+    rename.cpp
+  HDRS
+    ../rename.h
+  DEPENDS
+    libc.hdr.types.FILE
+    .gpu_file
+)
+
 add_entrypoint_object(
   stdin
   SRCS

libc/src/stdio/gpu/rename.cpp

@@ -0,0 +1,30 @@
+//===-- GPU Implementation of rename --------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "src/stdio/rename.h"
+#include "src/__support/CPP/string_view.h"
+#include "src/__support/macros/config.h"
+#include "src/stdio/gpu/file.h"
+
+#include "hdr/types/FILE.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+LLVM_LIBC_FUNCTION(int, rename, (const char *oldpath, const char *newpath)) {
+  int ret;
+  rpc::Client::Port port = rpc::client.open<RPC_RENAME>();
+  port.send_n(oldpath, internal::string_length(oldpath) + 1);
+  port.send_n(newpath, internal::string_length(newpath) + 1);
+  port.recv(
+      [&](rpc::Buffer *buffer) { ret = static_cast<int>(buffer->data[0]); });
+  port.close();
+
+  return ret;
+}
+
+} // namespace LIBC_NAMESPACE_DECL

libc/utils/gpu/server/rpc_server.cpp

@@ -392,6 +392,24 @@ rpc_status_t handle_server_impl(
     });
     break;
   }
+  case RPC_RENAME: {
+    uint64_t oldsizes[lane_size] = {0};
+    uint64_t newsizes[lane_size] = {0};
+    void *oldpath[lane_size] = {nullptr};
+    void *newpath[lane_size] = {nullptr};
+    port->recv_n(oldpath, oldsizes,
+                 [&](uint64_t size) { return new char[size]; });
+    port->recv_n(newpath, newsizes,
+                 [&](uint64_t size) { return new char[size]; });
+    port->send([&](rpc::Buffer *buffer, uint32_t id) {
+      buffer->data[0] = static_cast<uint64_t>(
+          rename(reinterpret_cast<const char *>(oldpath[id]),
+                 reinterpret_cast<const char *>(newpath[id])));
+      delete[] reinterpret_cast<uint8_t *>(oldpath[id]);
+      delete[] reinterpret_cast<uint8_t *>(newpath[id]);
+    });
+    break;
+  }
   case RPC_SYSTEM: {
     uint64_t sizes[lane_size] = {0};
     void *args[lane_size] = {nullptr};