8 files changed, 286 insertions, 5 deletions
diff --git a/libc/src/stdio/CMakeLists.txt b/libc/src/stdio/CMakeLists.txt
index 6cd4f2c..9d25326 100644
--- a/libc/src/stdio/CMakeLists.txt
+++ b/libc/src/stdio/CMakeLists.txt
@@ -1,3 +1,23 @@
+# Helper function that creates an alias if a target specific implementation
+# exists, otherwise it uses a generic one.
+function(add_stdio_entrypoint_object name)
+  if(TARGET libc.src.stdio.${LIBC_TARGET_OS}.${name})
+    add_entrypoint_object(
+      ${name}
+      ALIAS
+      DEPENDS
+        .${LIBC_TARGET_OS}.${name}
+    )
+  elseif(TARGET libc.src.stdio.generic_${name})
+    add_entrypoint_object(
+      ${name}
+      ALIAS
+      DEPENDS
+        .${LIBC_TARGET_OS}.${name}
+    )
+  endif()
+endfunction(add_stdio_entrypoint_object)
+
 if(EXISTS ${CMAKE_CURRENT_SOURCE_DIR}/${LIBC_TARGET_OS})
   add_subdirectory(${CMAKE_CURRENT_SOURCE_DIR}/${LIBC_TARGET_OS})
 endif()
@@ -322,7 +342,7 @@ add_entrypoint_object(
 )
 
 add_entrypoint_object(
-  fputs
+  generic_fputs
   SRCS
     fputs.cpp
   HDRS
@@ -336,7 +356,7 @@ add_entrypoint_object(
 
 
 add_entrypoint_object(
-  puts
+  generic_puts
   SRCS
     puts.cpp
   HDRS
@@ -386,7 +406,7 @@ add_entrypoint_object(
 )
 
 add_entrypoint_object(
-  stdin
+  generic_stdin
   SRCS
     stdin.cpp
   HDRS
@@ -398,7 +418,7 @@ add_entrypoint_object(
 )
 
 add_entrypoint_object(
-  stdout
+  generic_stdout
   SRCS
     stdout.cpp
   HDRS
@@ -410,7 +430,7 @@ add_entrypoint_object(
 )
 
 add_entrypoint_object(
-  stderr
+  generic_stderr
   SRCS
     stderr.cpp
   HDRS
@@ -608,3 +628,10 @@ add_entrypoint_object(
   DEPENDS
     .${LIBC_TARGET_OS}.remove
 )
+
+# These entrypoints have multiple potential implementations.
+add_stdio_entrypoint_object(puts)
+add_stdio_entrypoint_object(fputs)
+add_stdio_entrypoint_object(stdin)
+add_stdio_entrypoint_object(stdout)
+add_stdio_entrypoint_object(stderr)
diff --git a/libc/src/stdio/gpu/CMakeLists.txt b/libc/src/stdio/gpu/CMakeLists.txt
new file mode 100644
index 0000000..f679557
--- /dev/null
+++ b/libc/src/stdio/gpu/CMakeLists.txt
@@ -0,0 +1,61 @@
+add_header_library(
+  gpu_file
+  HDRS
+    file.h
+  DEPENDS
+    libc.src.__support.common
+    libc.src.__support.CPP.string_view
+    libc.src.__support.RPC.rpc_client
+)
+
+add_entrypoint_object(
+  puts
+  SRCS
+    puts.cpp
+  HDRS
+    ../puts.h
+  DEPENDS
+    libc.include.stdio
+    .gpu_file
+)
+
+add_entrypoint_object(
+  fputs
+  SRCS
+    fputs.cpp
+  HDRS
+    ../fputs.h
+  DEPENDS
+    libc.include.stdio
+    .gpu_file
+)
+
+add_entrypoint_object(
+  stdin
+  SRCS
+    stdin.cpp
+  HDRS
+    ../stdin.h
+  DEPENDS
+    libc.include.stdio
+)
+
+add_entrypoint_object(
+  stdout
+  SRCS
+    stdout.cpp
+  HDRS
+    ../stdout.h
+  DEPENDS
+    libc.include.stdio
+)
+
+add_entrypoint_object(
+  stderr
+  SRCS
+    stderr.cpp
+  HDRS
+    ../stderr.h
+  DEPENDS
+    libc.include.stdio
+)
diff --git a/libc/src/stdio/gpu/file.h b/libc/src/stdio/gpu/file.h
new file mode 100644
index 0000000..c7b2559
--- /dev/null
+++ b/libc/src/stdio/gpu/file.h
@@ -0,0 +1,89 @@
+//===--- GPU helper functions--------------------===//
+//
+// 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/__support/RPC/rpc_client.h"
+#include "src/string/string_utils.h"
+
+#include <stdio.h>
+
+namespace __llvm_libc {
+namespace file {
+
+LIBC_INLINE uint64_t write_to_stdout(const void *data, size_t size) {
+  uint64_t ret = 0;
+  rpc::Client::Port port = rpc::client.open<RPC_WRITE_TO_STDOUT>();
+  port.send_n(data, size);
+  port.recv([&](rpc::Buffer *buffer) {
+    ret = reinterpret_cast<uint64_t *>(buffer->data)[0];
+  });
+  port.close();
+  return ret;
+}
+
+LIBC_INLINE uint64_t write_to_stderr(const void *data, size_t size) {
+  uint64_t ret = 0;
+  rpc::Client::Port port = rpc::client.open<RPC_WRITE_TO_STDERR>();
+  port.send_n(data, size);
+  port.recv([&](rpc::Buffer *buffer) {
+    ret = reinterpret_cast<uint64_t *>(buffer->data)[0];
+  });
+  port.close();
+  return ret;
+}
+
+LIBC_INLINE uint64_t write_to_stream(uintptr_t file, const void *data,
+                                     size_t size) {
+  uint64_t ret = 0;
+  rpc::Client::Port port = rpc::client.open<RPC_WRITE_TO_STREAM>();
+  port.send([&](rpc::Buffer *buffer) {
+    reinterpret_cast<uintptr_t *>(buffer->data)[0] = file;
+  });
+  port.send_n(data, size);
+  port.recv([&](rpc::Buffer *buffer) {
+    ret = reinterpret_cast<uint64_t *>(buffer->data)[0];
+  });
+  port.close();
+  return ret;
+}
+
+LIBC_INLINE uint64_t write(FILE *f, const void *data, size_t size) {
+  if (f == stdout)
+    return write_to_stdout(data, size);
+  else if (f == stderr)
+    return write_to_stderr(data, size);
+  else
+    return write_to_stream(reinterpret_cast<uintptr_t>(f), data, size);
+}
+
+LIBC_INLINE uint64_t read_from_stdin(void *buf, size_t size) {
+  uint64_t ret = 0;
+  uint64_t recv_size;
+  rpc::Client::Port port = rpc::client.open<RPC_READ_FROM_STDIN>();
+  port.send([=](rpc::Buffer *buffer) { buffer->data[0] = size; });
+  port.recv_n(&buf, &recv_size, [&](uint64_t) { return buf; });
+  port.recv([&](rpc::Buffer *buffer) { ret = buffer->data[0]; });
+  port.close();
+  return ret;
+}
+
+LIBC_INLINE uint64_t read_from_stream(uintptr_t file, void *buf, size_t size) {
+  uint64_t ret = 0;
+  uint64_t recv_size;
+  rpc::Client::Port port = rpc::client.open<RPC_READ_FROM_STREAM>();
+  port.send([=](rpc::Buffer *buffer) {
+    buffer->data[0] = size;
+    buffer->data[1] = file;
+  });
+  port.recv_n(&buf, &recv_size, [&](uint64_t) { return buf; });
+  port.recv([&](rpc::Buffer *buffer) { ret = buffer->data[0]; });
+  port.close();
+  return ret;
+}
+
+} // namespace file
+} // namespace __llvm_libc
diff --git a/libc/src/stdio/gpu/fputs.cpp b/libc/src/stdio/gpu/fputs.cpp
new file mode 100644
index 0000000..c5919e8
--- /dev/null
+++ b/libc/src/stdio/gpu/fputs.cpp
@@ -0,0 +1,27 @@
+//===-- GPU Implementation of fputs ---------------------------------------===//
+//
+// 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/fputs.h"
+#include "src/__support/CPP/string_view.h"
+#include "src/errno/libc_errno.h"
+#include "src/stdio/gpu/file.h"
+
+#include <stdio.h>
+
+namespace __llvm_libc {
+
+LLVM_LIBC_FUNCTION(int, fputs,
+                   (const char *__restrict str, ::FILE *__restrict stream)) {
+  cpp::string_view str_view(str);
+  auto written = file::write(stream, str, str_view.size());
+  if (written != str_view.size())
+    return EOF;
+  return 0;
+}
+
+} // namespace __llvm_libc
diff --git a/libc/src/stdio/gpu/puts.cpp b/libc/src/stdio/gpu/puts.cpp
new file mode 100644
index 0000000..58a3534
--- /dev/null
+++ b/libc/src/stdio/gpu/puts.cpp
@@ -0,0 +1,29 @@
+//===-- GPU Implementation of puts ----------------------------------------===//
+//
+// 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/puts.h"
+#include "src/__support/CPP/string_view.h"
+#include "src/errno/libc_errno.h"
+#include "src/stdio/gpu/file.h"
+
+#include <stdio.h>
+
+namespace __llvm_libc {
+
+LLVM_LIBC_FUNCTION(int, puts, (const char *__restrict str)) {
+  cpp::string_view str_view(str);
+  auto written = file::write(stdout, str, str_view.size());
+  if (written != str_view.size())
+    return EOF;
+  written = file::write(stdout, "\n", 1);
+  if (written != 1)
+    return EOF;
+  return 0;
+}
+
+} // namespace __llvm_libc
diff --git a/libc/src/stdio/gpu/stderr.cpp b/libc/src/stdio/gpu/stderr.cpp
new file mode 100644
index 0000000..5e7b79e
--- /dev/null
+++ b/libc/src/stdio/gpu/stderr.cpp
@@ -0,0 +1,16 @@
+//===-- Definition of the global stderr object ----------------------------===//
+//
+// 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 <stdio.h>
+
+namespace __llvm_libc {
+static struct {
+} stub;
+FILE *stderr = reinterpret_cast<FILE *>(&stub);
+} // namespace __llvm_libc
+extern "C" FILE *stderr = reinterpret_cast<FILE *>(&__llvm_libc::stub);
diff --git a/libc/src/stdio/gpu/stdin.cpp b/libc/src/stdio/gpu/stdin.cpp
new file mode 100644
index 0000000..408852b
--- /dev/null
+++ b/libc/src/stdio/gpu/stdin.cpp
@@ -0,0 +1,16 @@
+//===-- Definition of the global stdin object -----------------------------===//
+//
+// 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 <stdio.h>
+
+namespace __llvm_libc {
+static struct {
+} stub;
+FILE *stdin = reinterpret_cast<FILE *>(&stub);
+} // namespace __llvm_libc
+extern "C" FILE *stdin = reinterpret_cast<FILE *>(&__llvm_libc::stub);
diff --git a/libc/src/stdio/gpu/stdout.cpp b/libc/src/stdio/gpu/stdout.cpp
new file mode 100644
index 0000000..02425d3
--- /dev/null
+++ b/libc/src/stdio/gpu/stdout.cpp
@@ -0,0 +1,16 @@
+//===-- Definition of the global stdout object ----------------------------===//
+//
+// 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 <stdio.h>
+
+namespace __llvm_libc {
+static struct {
+} stub;
+FILE *stdout = reinterpret_cast<FILE *>(&stub);
+} // namespace __llvm_libc
+extern "C" FILE *stdout = reinterpret_cast<FILE *>(&__llvm_libc::stub);