[libc] add wcslen

Author: RossComputerGuy

libc/config/gpu/entrypoints.txt

@@ -261,6 +261,7 @@ set(TARGET_LIBC_ENTRYPOINTS
     libc.src.time.nanosleep
 
     # wchar.h entrypoints
+    libc.src.wchar.wcslen
     libc.src.wchar.wmemchr
     libc.src.wchar.wctob
 

libc/config/linux/aarch64/entrypoints.txt

@@ -349,6 +349,7 @@ set(TARGET_LIBC_ENTRYPOINTS
     libc.src.unistd.write
 
     # wchar.h entrypoints
+    libc.src.wchar.wcslen
     libc.src.wchar.wmemchr
     libc.src.wchar.wctob
 )

libc/config/linux/riscv/entrypoints.txt

@@ -346,6 +346,7 @@ set(TARGET_LIBC_ENTRYPOINTS
     libc.src.unistd.write
 
     # wchar.h entrypoints
+    libc.src.wchar.wcslen
     libc.src.wchar.wmemchr
     libc.src.wchar.wctob
 )

libc/config/linux/x86_64/entrypoints.txt

@@ -348,6 +348,7 @@ set(TARGET_LIBC_ENTRYPOINTS
     libc.src.unistd.write
 
     # wchar.h entrypoints
+    libc.src.wchar.wcslen
     libc.src.wchar.wmemchr
     libc.src.wchar.wctob
     libc.src.wchar.btowc

libc/hdrgen/yaml/wchar.yaml

@@ -22,3 +22,9 @@ functions:
       - type: const wchar_t *
       - type: wchar_t
       - type: size_t
+  - name: wcslen
+    standards:
+      - stdc
+    return_type: size_t
+    arguments:
+      - type: const wchar_t *

libc/src/wchar/wcslen.cpp

@@ -0,0 +1,22 @@
+//===-- Implementation of wcslen ------------------------------------------===//
+//
+// 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/wchar/wcslen.h"
+#include "src/__support/common.h"
+#include "src/__support/macros/config.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+LLVM_LIBC_FUNCTION(size_t, wcslen, (const wchar_t *s)) {
+  size_t length = 0;
+  while (s[length++])
+    ;
+  return length;
+}
+
+} // namespace LIBC_NAMESPACE_DECL

libc/src/wchar/wcslen.h

@@ -0,0 +1,22 @@
+//===-- Implementation header for wcslen ------------------------*- 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_WCHAR_WCSLEN_H
+#define LLVM_LIBC_SRC_WCHAR_WCSLEN_H
+
+#include "hdr/types/size_t.h"
+#include "hdr/types/wchar_t.h"
+#include "src/__support/macros/config.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+size_t wcslen(const wchar_t *s);
+
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LLVM_LIBC_SRC_WCHAR_WCSLEN_H