[libc] Move mbtowc, mbstowcs and inverse functions to stdlib.h (#168455)

These functions should be declared in `stdlib.h`, not `wchar.h`, as
confusing as it is. Move them to the proper header file and matching
directories in src/ and test/ trees.

This was discovered while testing libc++ build against llvm-libc, which
re-declares functions like mbtowc in std-namespace in `<cstdlib>`
header, and then uses those functions in its locale implementation.

Author: vonosmas

libc/config/linux/x86_64/entrypoints.txt

@@ -1254,7 +1254,11 @@ if(LLVM_LIBC_FULL_BUILD)
     libc.src.stdlib.atexit
     libc.src.stdlib.exit
     libc.src.stdlib.getenv
+    libc.src.stdlib.mbstowcs
+    libc.src.stdlib.mbtowc
     libc.src.stdlib.quick_exit
+    libc.src.stdlib.wcstombs
+    libc.src.stdlib.wctomb
 
     # signal.h entrypoints
     libc.src.signal.kill
@@ -1372,13 +1376,9 @@ if(LLVM_LIBC_FULL_BUILD)
     libc.src.wchar.mbrlen
     libc.src.wchar.mbsinit
     libc.src.wchar.mbrtowc
-    libc.src.wchar.mbtowc
-    libc.src.wchar.mbstowcs
     libc.src.wchar.mbsrtowcs
     libc.src.wchar.mbsnrtowcs
     libc.src.wchar.wcrtomb
-    libc.src.wchar.wctomb
-    libc.src.wchar.wcstombs
     libc.src.wchar.wcsrtombs
     libc.src.wchar.wcsnrtombs
 

libc/include/stdlib.yaml

@@ -17,6 +17,7 @@ types:
   - type_name: lldiv_t
   - type_name: locale_t
   - type_name: size_t
+  - type_name: wchar_t  
 enums: []
 objects: []
 functions:
@@ -135,6 +136,22 @@ functions:
     arguments:
       - type: long long
       - type: long long
+  - name: mbstowcs
+    standards:
+      - stdc
+    return_type: size_t
+    arguments:
+      - type: wchar_t *__restrict
+      - type: const char *__restrict
+      - type: size_t
+  - name: mbtowc
+    standards:
+      - stdc
+    return_type: int
+    arguments:
+      - type: wchar_t *__restrict
+      - type: const char *__restrict
+      - type: size_t
   - name: memalignment
     standards:
       - stdc
@@ -332,3 +349,18 @@ functions:
     return_type: int
     arguments:
       - type: const char *
+  - name: wctomb
+    standards:
+      - stdc
+    return_type: int
+    arguments:
+      - type: char *
+      - type: wchar_t
+  - name: wcstombs
+    standards:
+      - stdc
+    return_type: size_t
+    arguments:
+      - type: char *__restrict
+      - type: const wchar_t *__restrict
+      - type: size_t

libc/include/wchar.yaml

@@ -50,14 +50,6 @@ functions:
       - type: const char *__restrict
       - type: size_t
       - type: mbstate_t *__restrict
-  - name: mbtowc
-    standards:
-      - stdc
-    return_type: int
-    arguments:
-      - type: wchar_t *__restrict
-      - type: const char *__restrict
-      - type: size_t
   - name: mbsnrtowcs
     standards:
       - stdc
@@ -77,14 +69,6 @@ functions:
       - type: const char **__restrict
       - type: size_t
       - type: mbstate_t *__restrict
-  - name: mbstowcs
-    standards:
-      - stdc
-    return_type: size_t
-    arguments:
-      - type: wchar_t *__restrict
-      - type: const char *__restrict
-      - type: size_t
   - name: mbsinit
     standards:
       - stdc
@@ -269,13 +253,6 @@ functions:
       - type: char *__restrict
       - type: wchar_t
       - type: mbstate_t *__restrict
-  - name: wctomb
-    standards:
-      - stdc
-    return_type: int
-    arguments:
-      - type: char *
-      - type: wchar_t
   - name: wcscpy
     standards:
       - stdc
@@ -336,14 +313,6 @@ functions:
       - type: const wchar_t *__restrict
       - type: wchar_t **__restrict
       - type: int
-  - name: wcstombs
-    standards:
-      - stdc
-    return_type: size_t
-    arguments:
-      - type: char *__restrict
-      - type: const wchar_t *__restrict
-      - type: size_t
   - name: wcstoul
     standards:
       - stdc

libc/src/stdlib/CMakeLists.txt

@@ -368,6 +368,65 @@ add_entrypoint_object(
     libc.hdr.types.size_t
 )
 
+add_entrypoint_object(
+  mbtowc
+  SRCS
+    mbtowc.cpp
+  HDRS
+    mbtowc.h
+  DEPENDS
+    libc.hdr.types.size_t
+    libc.hdr.types.wchar_t
+    libc.src.__support.common
+    libc.src.__support.macros.config
+    libc.src.__support.libc_errno
+    libc.src.__support.wchar.mbrtowc
+    libc.src.__support.wchar.mbstate
+)
+
+add_entrypoint_object(
+  mbstowcs
+  SRCS
+    mbstowcs.cpp
+  HDRS
+    mbstowcs.h
+  DEPENDS
+    libc.hdr.types.size_t
+    libc.hdr.types.wchar_t
+    libc.src.__support.common
+    libc.src.__support.macros.config
+    libc.src.__support.macros.null_check
+    libc.src.__support.libc_errno
+    libc.src.__support.wchar.mbstate
+    libc.src.__support.wchar.mbsnrtowcs
+)
+
+add_entrypoint_object(
+  wctomb
+  SRCS
+    wctomb.cpp
+  HDRS
+    wctomb.h
+  DEPENDS
+    libc.hdr.types.wchar_t
+    libc.src.__support.wchar.wcrtomb
+    libc.src.__support.wchar.mbstate
+    libc.src.__support.libc_errno
+)
+
+add_entrypoint_object(
+  wcstombs
+  SRCS
+    wcstombs.cpp
+  HDRS
+    wcstombs.h
+  DEPENDS
+    libc.hdr.types.wchar_t
+    libc.src.__support.wchar.mbstate
+    libc.src.__support.wchar.wcsnrtombs
+    libc.src.__support.libc_errno
+)
+
 if(NOT LIBC_TARGET_OS_IS_BAREMETAL AND NOT LIBC_TARGET_OS_IS_GPU)
   if(LLVM_LIBC_INCLUDE_SCUDO)
     set(SCUDO_DEPS "")

libc/src/wchar/mbstowcs.cpp renamed to libc/src/stdlib/mbstowcs.cpp

@@ -6,7 +6,7 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "src/wchar/mbstowcs.h"
+#include "src/stdlib/mbstowcs.h"
 
 #include "hdr/types/size_t.h"
 #include "hdr/types/wchar_t.h"

libc/src/wchar/mbstowcs.h renamed to libc/src/stdlib/mbstowcs.h

@@ -6,8 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-#ifndef LLVM_LIBC_SRC_WCHAR_MBSTOWCS_H
-#define LLVM_LIBC_SRC_WCHAR_MBSTOWCS_H
+#ifndef LLVM_LIBC_SRC_STDLIB_MBSTOWCS_H
+#define LLVM_LIBC_SRC_STDLIB_MBSTOWCS_H
 
 #include "hdr/types/size_t.h"
 #include "hdr/types/wchar_t.h"
@@ -19,4 +19,4 @@ size_t mbstowcs(wchar_t *__restrict pwcs, const char *__restrict s, size_t n);
 
 } // namespace LIBC_NAMESPACE_DECL
 
-#endif // LLVM_LIBC_SRC_WCHAR_MBSTOWCS_H
+#endif // LLVM_LIBC_SRC_STDLIB_MBSTOWCS_H

libc/src/wchar/mbtowc.cpp renamed to libc/src/stdlib/mbtowc.cpp

@@ -6,7 +6,7 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "src/wchar/mbtowc.h"
+#include "src/stdlib/mbtowc.h"
 
 #include "hdr/types/size_t.h"
 #include "hdr/types/wchar_t.h"

libc/src/wchar/mbtowc.h renamed to libc/src/stdlib/mbtowc.h

@@ -6,8 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-#ifndef LLVM_LIBC_SRC_WCHAR_MBTOWC_H
-#define LLVM_LIBC_SRC_WCHAR_MBTOWC_H
+#ifndef LLVM_LIBC_SRC_STDLIB_MBTOWC_H
+#define LLVM_LIBC_SRC_STDLIB_MBTOWC_H
 
 #include "hdr/types/size_t.h"
 #include "hdr/types/wchar_t.h"
@@ -19,4 +19,4 @@ int mbtowc(wchar_t *__restrict pwc, const char *__restrict s, size_t n);
 
 } // namespace LIBC_NAMESPACE_DECL
 
-#endif // LLVM_LIBC_SRC_WCHAR_MBTOWC_H
+#endif // LLVM_LIBC_SRC_STDLIB_MBTOWC_H

libc/src/wchar/wcstombs.cpp renamed to libc/src/stdlib/wcstombs.cpp

@@ -6,7 +6,7 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "src/wchar/wcstombs.h"
+#include "src/stdlib/wcstombs.h"
 
 #include "hdr/types/char32_t.h"
 #include "hdr/types/size_t.h"

libc/src/wchar/wcstombs.h renamed to libc/src/stdlib/wcstombs.h

@@ -6,8 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-#ifndef LLVM_LIBC_SRC_WCHAR_WCSTOMBS_H
-#define LLVM_LIBC_SRC_WCHAR_WCSTOMBS_H
+#ifndef LLVM_LIBC_SRC_STDLIB_WCSTOMBS_H
+#define LLVM_LIBC_SRC_STDLIB_WCSTOMBS_H
 
 #include "hdr/types/size_t.h"
 #include "hdr/types/wchar_t.h"
@@ -19,4 +19,4 @@ size_t wcstombs(char *__restrict s, const wchar_t *__restrict pwcs, size_t n);
 
 } // namespace LIBC_NAMESPACE_DECL
 
-#endif // LLVM_LIBC_SRC_WCHAR_WCSTOMBS_H
+#endif // LLVM_LIBC_SRC_STDLIB_WCSTOMBS_H