[libc-commits] [libc] [libc] wcpcpy implementation (PR #144802)
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libc-commits at lists.llvm.org
Fri Jun 20 10:31:01 PDT 2025
https://github.com/sribee8 updated https://github.com/llvm/llvm-project/pull/144802
>From 2f0b885976b6975acd544db6d502d52d8a7c5b56 Mon Sep 17 00:00:00 2001
From: Sriya Pratipati <sriyap at google.com>
Date: Wed, 18 Jun 2025 21:46:05 +0000
Subject: [PATCH 1/2] [libc] wcpcpy implementation
Implemented wcpcpy and tests.
---
libc/config/linux/x86_64/entrypoints.txt | 1 +
libc/include/wchar.yaml | 7 ++++
libc/src/wchar/CMakeLists.txt | 12 ++++++
libc/src/wchar/wcpcpy.cpp | 29 ++++++++++++++
libc/src/wchar/wcpcpy.h | 21 ++++++++++
libc/test/src/wchar/CMakeLists.txt | 10 +++++
libc/test/src/wchar/wcpcpy_test.cpp | 50 ++++++++++++++++++++++++
7 files changed, 130 insertions(+)
create mode 100644 libc/src/wchar/wcpcpy.cpp
create mode 100644 libc/src/wchar/wcpcpy.h
create mode 100644 libc/test/src/wchar/wcpcpy_test.cpp
diff --git a/libc/config/linux/x86_64/entrypoints.txt b/libc/config/linux/x86_64/entrypoints.txt
index aa2079faed409..8c6c540a67230 100644
--- a/libc/config/linux/x86_64/entrypoints.txt
+++ b/libc/config/linux/x86_64/entrypoints.txt
@@ -384,6 +384,7 @@ set(TARGET_LIBC_ENTRYPOINTS
libc.src.wchar.wcsncat
libc.src.wchar.wcscpy
libc.src.wchar.wmemchr
+ libc.src.wchar.wcpcpy
# sys/uio.h entrypoints
libc.src.sys.uio.writev
diff --git a/libc/include/wchar.yaml b/libc/include/wchar.yaml
index 84db73d8f01ea..2962984c254ce 100644
--- a/libc/include/wchar.yaml
+++ b/libc/include/wchar.yaml
@@ -157,3 +157,10 @@ functions:
arguments:
- type: wchar_t *__restrict
- type: const wchar_t *__restrict
+ - name: wcpcpy
+ standards:
+ - stdc
+ return_type: wchar_t *
+ arguments:
+ - type: wchar_t *__restrict
+ - type: const wchar_t *__restrict
diff --git a/libc/src/wchar/CMakeLists.txt b/libc/src/wchar/CMakeLists.txt
index 491dd5b34340a..65c38ac81a90f 100644
--- a/libc/src/wchar/CMakeLists.txt
+++ b/libc/src/wchar/CMakeLists.txt
@@ -45,6 +45,18 @@ add_entrypoint_object(
libc.hdr.types.wchar_t
)
+add_entrypoint_object(
+ wcpcpy
+ SRCS
+ wcpcpy.cpp
+ HDRS
+ wcpcpy.h
+ DEPENDS
+ libc.hdr.types.size_t
+ libc.hdr.wchar_macros
+ libc.src.string.string_utils
+)
+
add_entrypoint_object(
wcschr
SRCS
diff --git a/libc/src/wchar/wcpcpy.cpp b/libc/src/wchar/wcpcpy.cpp
new file mode 100644
index 0000000000000..5ac30f7af077b
--- /dev/null
+++ b/libc/src/wchar/wcpcpy.cpp
@@ -0,0 +1,29 @@
+//===-- Implementation of wcpcpy ------------------------------------------===//
+//
+// 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/wcpcpy.h"
+
+#include "hdr/types/size_t.h"
+#include "hdr/types/wchar_t.h"
+#include "src/__support/common.h"
+#include "src/__support/macros/config.h"
+#include "src/string/string_utils.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+LLVM_LIBC_FUNCTION(wchar_t *, wcpcpy,
+ (wchar_t *__restrict s1, const wchar_t *__restrict s2)) {
+ size_t size = internal::string_length(s2);
+ __builtin_memcpy(s1, s2, (size + 1) * sizeof(wchar_t));
+ wchar_t *result = s1 + size;
+ if (result != nullptr)
+ return result;
+ return nullptr;
+}
+
+} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/wchar/wcpcpy.h b/libc/src/wchar/wcpcpy.h
new file mode 100644
index 0000000000000..333491fc13abb
--- /dev/null
+++ b/libc/src/wchar/wcpcpy.h
@@ -0,0 +1,21 @@
+//===-- Implementation header for wcpcpy ----------------------------------===//
+//
+// 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_WCPCPY_H
+#define LLVM_LIBC_SRC_WCHAR_WCPCPY_H
+
+#include "hdr/types/wchar_t.h"
+#include "src/__support/macros/config.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+wchar_t *wcpcpy(wchar_t *__restrict ws1, const wchar_t *__restrict ws2);
+
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LLVM_LIBC_SRC_WCHAR_WCPCPY_H
diff --git a/libc/test/src/wchar/CMakeLists.txt b/libc/test/src/wchar/CMakeLists.txt
index 4990b6953348b..d7444de94fe17 100644
--- a/libc/test/src/wchar/CMakeLists.txt
+++ b/libc/test/src/wchar/CMakeLists.txt
@@ -204,3 +204,13 @@ add_libc_test(
DEPENDS
libc.src.wchar.wcscpy
)
+
+add_libc_test(
+ wcpcpy_test
+ SUITE
+ libc_wchar_unittests
+ SRCS
+ wcpcpy_test.cpp
+ DEPENDS
+ libc.src.wchar.wcpcpy
+)
diff --git a/libc/test/src/wchar/wcpcpy_test.cpp b/libc/test/src/wchar/wcpcpy_test.cpp
new file mode 100644
index 0000000000000..c59b61fb131b2
--- /dev/null
+++ b/libc/test/src/wchar/wcpcpy_test.cpp
@@ -0,0 +1,50 @@
+//===-- Unittests for wcpcpy ---------------------------------------------===//
+//
+// 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 "hdr/types/wchar_t.h"
+#include "src/wchar/wcpcpy.h"
+#include "test/UnitTest/Test.h"
+
+TEST(LlvmLibcWCPCpyTest, EmptySrc) {
+ // Empty src should lead to empty destination.
+ wchar_t dest[4] = {L'a', L'b', L'c', L'\0'};
+ const wchar_t *src = L"";
+ LIBC_NAMESPACE::wcpcpy(dest, src);
+ ASSERT_TRUE(dest[0] == src[0]);
+ ASSERT_TRUE(dest[0] == L'\0');
+}
+
+TEST(LlvmLibcWCPCpyTest, EmptyDest) {
+ // Empty dest should result in src
+ const wchar_t *src = L"abc";
+ wchar_t dest[4];
+ wchar_t *result = LIBC_NAMESPACE::wcpcpy(dest, src);
+ ASSERT_EQ(dest + 3, result);
+ ASSERT_TRUE(result[0] == L'\0');
+ ASSERT_TRUE(dest[0] == L'a');
+ ASSERT_TRUE(dest[1] == L'b');
+ ASSERT_TRUE(dest[2] == L'c');
+}
+
+TEST(LlvmLibcWCPCpyTest, OffsetDest) {
+ // Offsetting should result in a concatenation.
+ const wchar_t *src = L"abc";
+ wchar_t dest[7];
+ dest[0] = L'x';
+ dest[1] = L'y';
+ dest[2] = L'z';
+ wchar_t *result = LIBC_NAMESPACE::wcpcpy(dest + 3, src);
+ ASSERT_TRUE(dest[0] == L'x');
+ ASSERT_TRUE(dest[1] == L'y');
+ ASSERT_TRUE(dest[2] == L'z');
+ ASSERT_TRUE(dest[3] == src[0]);
+ ASSERT_TRUE(dest[4] == src[1]);
+ ASSERT_TRUE(dest[5] == src[2]);
+ ASSERT_TRUE(result[0] == L'\0');
+ ASSERT_EQ(dest + 6, result);
+}
>From f8177469fe3cb98a9e0a8cd09660e5269d987384 Mon Sep 17 00:00:00 2001
From: Sriya Pratipati <sriyap at google.com>
Date: Fri, 20 Jun 2025 17:30:45 +0000
Subject: [PATCH 2/2] fixed return logic
---
libc/src/wchar/wcpcpy.cpp | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)
diff --git a/libc/src/wchar/wcpcpy.cpp b/libc/src/wchar/wcpcpy.cpp
index 5ac30f7af077b..9e2b12f09eb05 100644
--- a/libc/src/wchar/wcpcpy.cpp
+++ b/libc/src/wchar/wcpcpy.cpp
@@ -21,9 +21,7 @@ LLVM_LIBC_FUNCTION(wchar_t *, wcpcpy,
size_t size = internal::string_length(s2);
__builtin_memcpy(s1, s2, (size + 1) * sizeof(wchar_t));
wchar_t *result = s1 + size;
- if (result != nullptr)
- return result;
- return nullptr;
+ return result;
}
} // namespace LIBC_NAMESPACE_DECL
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