[libc] Initial support for 'locale.h' in the LLVM libc

Summary:
This patch adds the macros and entrypoints associated with the
`locale.h` entrypoints.  These are mostly stubs, as we (for now and the
forseeable future) only expect to support the C and maybe C.UTF-8
locales in the LLVM libc.

Author: jhuber6

libc/config/gpu/entrypoints.txt

@@ -231,6 +231,15 @@ set(TARGET_LIBC_ENTRYPOINTS
     # wchar.h entrypoints
     libc.src.wchar.wctob
 
+    # locale.h entrypoints
+    libc.src.locale.localeconv
+    libc.src.locale.duplocale
+    libc.src.locale.freelocale
+    libc.src.locale.localeconv
+    libc.src.locale.newlocale
+    libc.src.locale.setlocale
+    libc.src.locale.uselocale
+
     # gpu/rpc.h entrypoints
     libc.src.gpu.rpc_host_call
 )

libc/config/gpu/headers.txt

@@ -16,6 +16,7 @@ set(TARGET_PUBLIC_HEADERS
     libc.include.wchar
     libc.include.uchar
     libc.include.features
+    libc.include.locale
 
     # Header for RPC extensions
     libc.include.gpu_rpc

libc/config/linux/x86_64/entrypoints.txt

@@ -981,6 +981,15 @@ if(LLVM_LIBC_FULL_BUILD)
     libc.src.time.nanosleep
     libc.src.time.time
 
+    # locale.h entrypoints
+    libc.src.locale.localeconv
+    libc.src.locale.duplocale
+    libc.src.locale.freelocale
+    libc.src.locale.localeconv
+    libc.src.locale.newlocale
+    libc.src.locale.setlocale
+    libc.src.locale.uselocale
+
     # unistd.h entrypoints
     libc.src.unistd.__llvm_libc_syscall
     libc.src.unistd._exit

libc/config/linux/x86_64/headers.txt

@@ -31,6 +31,7 @@ set(TARGET_PUBLIC_HEADERS
     libc.include.unistd
     libc.include.wchar
     libc.include.uchar
+    libc.include.locale
 
     libc.include.arpa_inet
 

libc/hdr/types/locale_t.h

@@ -0,0 +1,22 @@
+//===-- Definition of macros from locale_t.h ------------------------------===//
+//
+// 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_HDR_LOCALE_T_H
+#define LLVM_LIBC_HDR_LOCALE_T_H
+
+#ifdef LIBC_FULL_BUILD
+
+#include "include/llvm-libc-types/locale_t.h"
+
+#else // overlay mode
+
+#error "type not available in overlay mode"
+
+#endif // LLVM_LIBC_FULL_BUILD
+
+#endif // LLVM_LIBC_HDR_LOCALE_T_H

libc/include/CMakeLists.txt

@@ -700,6 +700,18 @@ add_header_macro(
     .llvm-libc-types.wchar_t
 )
 
+add_header_macro(
+  locale
+  ../libc/newhdrgen/yaml/locale.yaml
+  locale.h.def
+  locale.h
+  DEPENDS
+    .llvm_libc_common_h
+    .llvm-libc-macros.locale_macros
+    .llvm-libc-types.locale_t
+    .llvm-libc-types.struct_lconv
+)
+
 if(LIBC_TARGET_OS_IS_GPU)
   file(MAKE_DIRECTORY ${LIBC_INCLUDE_DIR}/gpu)
 

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

@@ -289,3 +289,9 @@ add_macro_header(
   HDR
     dlfcn-macros.h
 )
+
+add_macro_header(
+  locale_macros
+  HDR
+    locale-macros.h
+)

libc/include/llvm-libc-macros/locale-macros.h

@@ -0,0 +1,32 @@
+//===-- Definition of macros from locale.h --------------------------------===//
+//
+// 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_MACROS_LOCALE_MACROS_H
+#define LLVM_LIBC_MACROS_LOCALE_MACROS_H
+
+#include "../llvm-libc-types/locale_t.h"
+
+#define LC_CTYPE 0
+#define LC_NUMERIC 1
+#define LC_TIME 2
+#define LC_COLLATE 3
+#define LC_MONETARY 4
+#define LC_MESSAGES 5
+#define LC_ALL 6
+
+#define LC_GLOBAL_LOCALE ((locale_t)(-1))
+
+#define LC_CTYPE_MASK (1 << LC_CTYPE)
+#define LC_NUMERIC_MASK (1 << LC_NUMERIC)
+#define LC_TIME_MASK (1 << LC_TIME)
+#define LC_COLLATE_MASK (1 << LC_COLLATE)
+#define LC_MONETARY_MASK (1 << LC_MONETARY)
+#define LC_MESSAGES_MASK (1 << LC_MESSAGES)
+#define LC_ALL_MASK 0x7fffffff
+
+#endif // LLVM_LIBC_MACROS_LOCALE_MACROS_H

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

@@ -142,3 +142,5 @@ DEPENDS
   .fsblkcnt_t
   .fsfilcnt_t
 )
+add_header(locale_t HDR locale_t.h)
+add_header(struct_lconv HDR struct_lconv.h)

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

@@ -0,0 +1,22 @@
+//===-- Definition of type locale_t ---------------------------------------===//
+//
+// 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_LOCALE_T_H
+#define LLVM_LIBC_TYPES_LOCALE_T_H
+
+#define NUM_LOCALE_CATEGORIES 6
+
+struct __locale_data;
+
+struct __locale_t {
+  struct __locale_data *data[NUM_LOCALE_CATEGORIES];
+};
+
+typedef struct __locale_t *locale_t;
+
+#endif // LLVM_LIBC_TYPES_LOCALE_T_H