[libc] Stub out message catalog functions from <nl_types.h> (#164360)

Create a POSIX `<nl_types.h>` header with `catopen`, `catclose`, and
`catgets` function declarations.
Provide the stub/placeholder implementations which always return error.
This is consistent with the way
locales are currently (un-)implemented in llvm-libc.

Notably, providing `<nl_types.h>` fixes the last remaining issue with
building libc++ against llvm-libc
(on certain configuration of x86_64 Linux) after disabling threads and
wide-characters in libc++.

Author: vonosmas

libc/config/linux/x86_64/entrypoints.txt

@@ -1374,6 +1374,11 @@ if(LLVM_LIBC_FULL_BUILD)
     libc.src.wchar.wcstombs
     libc.src.wchar.wcsrtombs
     libc.src.wchar.wcsnrtombs
+
+    # nl_types.h entrypoints
+    libc.src.nl_types.catopen 
+    libc.src.nl_types.catclose
+    libc.src.nl_types.catgets
   )
 endif()
 

libc/config/linux/x86_64/headers.txt

@@ -19,6 +19,7 @@ set(TARGET_PUBLIC_HEADERS
     libc.include.malloc
     libc.include.math
     libc.include.netinet_in
+    libc.include.nl_types
     libc.include.poll
     libc.include.pthread
     libc.include.sched

libc/include/CMakeLists.txt

@@ -771,6 +771,14 @@ add_header_macro(
     .llvm-libc-macros.poll-macros
   )
 
+add_header_macro(
+  nl_types
+  ../libc/include/nl_types.yaml
+  nl_types.h
+  DEPENDS
+    .llvm-libc-types.nl_catd
+  )
+
 # UEFI spec references "Uefi.h" so we use that name for compatibility
 add_header_macro(
   uefi

libc/include/llvm-libc-types/CMakeLists.txt

@@ -46,6 +46,7 @@ add_header(mbstate_t HDR mbstate_t.h)
 add_header(mode_t HDR mode_t.h)
 add_header(mtx_t HDR mtx_t.h DEPENDS .__futex_word .__mutex_type)
 add_header(nfds_t HDR nfds_t.h)
+add_header(nl_catd HDR nl_catd.h)
 add_header(nlink_t HDR nlink_t.h)
 add_header(off_t HDR off_t.h)
 add_header(once_flag HDR once_flag.h DEPENDS .__futex_word)

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

@@ -0,0 +1,14 @@
+//===-- Definition of nl_catd type ----------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIBC_TYPES_NL_CATD_H
+#define LLVM_LIBC_TYPES_NL_CATD_H
+
+typedef void *nl_catd;
+
+#endif // LLVM_LIBC_TYPES_NL_CATD_H

libc/include/nl_types.yaml

@@ -0,0 +1,31 @@
+header: nl_types.h
+standards:
+  - posix
+macros: []
+types:
+  - type_name: nl_catd
+enums: []
+objects: []
+functions:
+  - name: catopen
+    standards:
+      - posix
+    return_type: nl_catd
+    arguments:
+      - type: const char *
+      - type: int
+  - name: catclose
+    standards:
+      - posix
+    return_type: int
+    arguments:
+      - type: nl_catd
+  - name: catgets
+    standards:
+      - posix
+    return_type: char *
+    arguments:
+      - type: nl_catd
+      - type: int
+      - type: int
+      - type: const char*

libc/src/CMakeLists.txt

@@ -37,6 +37,7 @@ add_subdirectory(arpa)
 add_subdirectory(assert)
 add_subdirectory(compiler)
 add_subdirectory(locale)
+add_subdirectory(nl_types)
 add_subdirectory(search)
 add_subdirectory(setjmp)
 add_subdirectory(signal)

libc/src/nl_types/CMakeLists.txt

@@ -0,0 +1,31 @@
+add_entrypoint_object(
+  catopen
+  SRCS
+    catopen.cpp
+  HDRS
+    catopen.h
+  DEPENDS
+    libc.include.llvm-libc-types.nl_catd
+    libc.src.errno.errno
+)
+
+add_entrypoint_object(
+  catclose
+  SRCS
+    catclose.cpp
+  HDRS
+    catclose.h
+  DEPENDS
+    libc.include.llvm-libc-types.nl_catd
+)
+
+add_entrypoint_object(
+  catgets
+  SRCS
+    catgets.cpp
+  HDRS
+    catgets.h
+  DEPENDS
+    libc.include.llvm-libc-types.nl_catd
+)
+

libc/src/nl_types/catclose.cpp

@@ -0,0 +1,22 @@
+//===-- Implementation of catclose ----------------------------------------===//
+//
+// 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/nl_types/catclose.h"
+#include "include/llvm-libc-types/nl_catd.h"
+#include "src/__support/common.h"
+#include "src/__support/macros/config.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+LLVM_LIBC_FUNCTION(int, catclose, ([[maybe_unused]] nl_catd catalog)) {
+  // TODO: Add implementation for message catalogs. For now, return error
+  // regardless of input.
+  return -1;
+}
+
+} // namespace LIBC_NAMESPACE_DECL

libc/src/nl_types/catclose.h

@@ -0,0 +1,21 @@
+//===-- Implementation header for catclose ----------------------*- C++ -*-===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIBC_SRC_NL_TYPES_CATCLOSE_H
+#define LLVM_LIBC_SRC_NL_TYPES_CATCLOSE_H
+
+#include "include/llvm-libc-types/nl_catd.h"
+#include "src/__support/macros/config.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+int catclose(nl_catd catalog);
+
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LLVM_LIBC_SRC_NL_TYPES_CATCLOSE_H