[libc-commits] [libc] [libc] implement `strings/ffs` (PR #129892)
via libc-commits
libc-commits at lists.llvm.org
Wed Mar 5 07:40:36 PST 2025
llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-libc
Author: None (c8ef)
<details>
<summary>Changes</summary>
This patch adds the `strings/ffs` function.
ref: https://pubs.opengroup.org/onlinepubs/9799919799/functions/ffs.html
Closes: #<!-- -->122054.
---
Full diff: https://github.com/llvm/llvm-project/pull/129892.diff
14 Files Affected:
- (modified) libc/config/linux/aarch64/entrypoints.txt (+3)
- (modified) libc/config/linux/x86_64/entrypoints.txt (+3)
- (modified) libc/include/strings.yaml (+18)
- (modified) libc/src/strings/CMakeLists.txt (+24)
- (added) libc/src/strings/ffs.cpp (+17)
- (added) libc/src/strings/ffs.h (+20)
- (added) libc/src/strings/ffsl.cpp (+17)
- (added) libc/src/strings/ffsl.h (+20)
- (added) libc/src/strings/ffsll.cpp (+17)
- (added) libc/src/strings/ffsll.h (+20)
- (modified) libc/test/src/strings/CMakeLists.txt (+30)
- (added) libc/test/src/strings/ffs_test.cpp (+25)
- (added) libc/test/src/strings/ffsl_test.cpp (+25)
- (added) libc/test/src/strings/ffsll_test.cpp (+25)
``````````diff
diff --git a/libc/config/linux/aarch64/entrypoints.txt b/libc/config/linux/aarch64/entrypoints.txt
index 6c2be4d3b0b99..c7beb3ef3fdfc 100644
--- a/libc/config/linux/aarch64/entrypoints.txt
+++ b/libc/config/linux/aarch64/entrypoints.txt
@@ -93,6 +93,9 @@ set(TARGET_LIBC_ENTRYPOINTS
libc.src.strings.bcmp
libc.src.strings.bcopy
libc.src.strings.bzero
+ libc.src.strings.ffs
+ libc.src.strings.ffsl
+ libc.src.strings.ffsll
libc.src.strings.index
libc.src.strings.rindex
libc.src.strings.strcasecmp
diff --git a/libc/config/linux/x86_64/entrypoints.txt b/libc/config/linux/x86_64/entrypoints.txt
index 779654422e35b..12dc87bf945fd 100644
--- a/libc/config/linux/x86_64/entrypoints.txt
+++ b/libc/config/linux/x86_64/entrypoints.txt
@@ -93,6 +93,9 @@ set(TARGET_LIBC_ENTRYPOINTS
libc.src.strings.bcmp
libc.src.strings.bcopy
libc.src.strings.bzero
+ libc.src.strings.ffs
+ libc.src.strings.ffsl
+ libc.src.strings.ffsll
libc.src.strings.index
libc.src.strings.rindex
libc.src.strings.strcasecmp
diff --git a/libc/include/strings.yaml b/libc/include/strings.yaml
index b6aa8f6d60b27..012805269f775 100644
--- a/libc/include/strings.yaml
+++ b/libc/include/strings.yaml
@@ -29,6 +29,24 @@ functions:
arguments:
- type: void *
- type: size_t
+ - name: ffs
+ standards:
+ - POSIX
+ return_type: int
+ arguments:
+ - int
+ - name: ffsl
+ standards:
+ - POSIX
+ return_type: int
+ arguments:
+ - long
+ - name: ffsll
+ standards:
+ - POSIX
+ return_type: int
+ arguments:
+ - long long
- name: index
standards:
- BSDExtensions
diff --git a/libc/src/strings/CMakeLists.txt b/libc/src/strings/CMakeLists.txt
index 5e84c7be1f7d6..aa0f8f51a5f59 100644
--- a/libc/src/strings/CMakeLists.txt
+++ b/libc/src/strings/CMakeLists.txt
@@ -54,6 +54,30 @@ add_entrypoint_object(
bcopy.h
)
+add_entrypoint_object(
+ ffs
+ SRCS
+ ffs.cpp
+ HDRS
+ ffs.h
+)
+
+add_entrypoint_object(
+ ffsl
+ SRCS
+ ffsl.cpp
+ HDRS
+ ffsl.h
+)
+
+add_entrypoint_object(
+ ffsll
+ SRCS
+ ffsll.cpp
+ HDRS
+ ffsll.h
+)
+
add_entrypoint_object(
index
SRCS
diff --git a/libc/src/strings/ffs.cpp b/libc/src/strings/ffs.cpp
new file mode 100644
index 0000000000000..4cf565fc335e7
--- /dev/null
+++ b/libc/src/strings/ffs.cpp
@@ -0,0 +1,17 @@
+//===-- Implementation of ffs ---------------------------------------------===//
+//
+// 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/strings/ffs.h"
+#include "src/__support/common.h"
+#include "src/__support/macros/config.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+LLVM_LIBC_FUNCTION(int, ffs, (int i)) { return __builtin_ffs(i); }
+
+} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/strings/ffs.h b/libc/src/strings/ffs.h
new file mode 100644
index 0000000000000..bf43c43caedb2
--- /dev/null
+++ b/libc/src/strings/ffs.h
@@ -0,0 +1,20 @@
+//===-- Implementation header for ffs ---------------------------*- 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_STRINGS_FFS_H
+#define LLVM_LIBC_SRC_STRINGS_FFS_H
+
+#include "src/__support/macros/config.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+int ffs(int i);
+
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LLVM_LIBC_SRC_STRINGS_FFS_H
diff --git a/libc/src/strings/ffsl.cpp b/libc/src/strings/ffsl.cpp
new file mode 100644
index 0000000000000..1373699d974ef
--- /dev/null
+++ b/libc/src/strings/ffsl.cpp
@@ -0,0 +1,17 @@
+//===-- Implementation of ffsl --------------------------------------------===//
+//
+// 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/strings/ffsl.h"
+#include "src/__support/common.h"
+#include "src/__support/macros/config.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+LLVM_LIBC_FUNCTION(int, ffsl, (long i)) { return __builtin_ffsl(i); }
+
+} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/strings/ffsl.h b/libc/src/strings/ffsl.h
new file mode 100644
index 0000000000000..1feca010b2ebb
--- /dev/null
+++ b/libc/src/strings/ffsl.h
@@ -0,0 +1,20 @@
+//===-- Implementation header for ffsl --------------------------*- 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_STRINGS_FFSL_H
+#define LLVM_LIBC_SRC_STRINGS_FFSL_H
+
+#include "src/__support/macros/config.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+int ffsl(long i);
+
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LLVM_LIBC_SRC_STRINGS_FFSL_H
diff --git a/libc/src/strings/ffsll.cpp b/libc/src/strings/ffsll.cpp
new file mode 100644
index 0000000000000..a0b6858c1a9ee
--- /dev/null
+++ b/libc/src/strings/ffsll.cpp
@@ -0,0 +1,17 @@
+//===-- Implementation of ffsll -------------------------------------------===//
+//
+// 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/strings/ffsll.h"
+#include "src/__support/common.h"
+#include "src/__support/macros/config.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+LLVM_LIBC_FUNCTION(int, ffsll, (long long i)) { return __builtin_ffsll(i); }
+
+} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/strings/ffsll.h b/libc/src/strings/ffsll.h
new file mode 100644
index 0000000000000..f059b8ab89b4e
--- /dev/null
+++ b/libc/src/strings/ffsll.h
@@ -0,0 +1,20 @@
+//===-- Implementation header for ffsll -------------------------*- 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_STRINGS_FFSLL_H
+#define LLVM_LIBC_SRC_STRINGS_FFSLL_H
+
+#include "src/__support/macros/config.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+int ffsll(long long i);
+
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LLVM_LIBC_SRC_STRINGS_FFSLL_H
diff --git a/libc/test/src/strings/CMakeLists.txt b/libc/test/src/strings/CMakeLists.txt
index 10f96b8531f68..baa22bb449c6c 100644
--- a/libc/test/src/strings/CMakeLists.txt
+++ b/libc/test/src/strings/CMakeLists.txt
@@ -12,6 +12,36 @@ add_libc_test(
LibcMemoryHelpers
)
+add_libc_test(
+ ffs_test
+ SUITE
+ libc-strings-tests
+ SRCS
+ ffs_test.cpp
+ DEPENDS
+ libc.src.strings.ffs
+)
+
+add_libc_test(
+ ffsl_test
+ SUITE
+ libc-strings-tests
+ SRCS
+ ffsl_test.cpp
+ DEPENDS
+ libc.src.strings.ffsl
+)
+
+add_libc_test(
+ ffsll_test
+ SUITE
+ libc-strings-tests
+ SRCS
+ ffsll_test.cpp
+ DEPENDS
+ libc.src.strings.ffsll
+)
+
add_libc_test(
index_test
SUITE
diff --git a/libc/test/src/strings/ffs_test.cpp b/libc/test/src/strings/ffs_test.cpp
new file mode 100644
index 0000000000000..5270837ec2ac0
--- /dev/null
+++ b/libc/test/src/strings/ffs_test.cpp
@@ -0,0 +1,25 @@
+//===-- Unittests for ffs -------------------------------------------------===//
+//
+// 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/strings/ffs.h"
+
+#include "src/__support/macros/config.h"
+#include "test/UnitTest/Test.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+TEST(LlvmLibcFfsTest, SimpleFfs) {
+ ASSERT_EQ(ffs(0), 0);
+ ASSERT_EQ(ffs(1), 1);
+ ASSERT_EQ(ffs(0xfbe71), 1);
+ ASSERT_EQ(ffs(0xfbe70), 5);
+ ASSERT_EQ(ffs(0x10), 5);
+ ASSERT_EQ(ffs(0x100), 9);
+}
+
+} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/test/src/strings/ffsl_test.cpp b/libc/test/src/strings/ffsl_test.cpp
new file mode 100644
index 0000000000000..1fcd2943fbb15
--- /dev/null
+++ b/libc/test/src/strings/ffsl_test.cpp
@@ -0,0 +1,25 @@
+//===-- Unittests for ffsl ------------------------------------------------===//
+//
+// 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/strings/ffsl.h"
+
+#include "src/__support/macros/config.h"
+#include "test/UnitTest/Test.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+TEST(LlvmLibcFfslTest, SimpleFfsl) {
+ ASSERT_EQ(ffsl(0L), 0);
+ ASSERT_EQ(ffsl(1L), 1);
+ ASSERT_EQ(ffsl(0xfbe71L), 1);
+ ASSERT_EQ(ffsl(0xfbe70L), 5);
+ ASSERT_EQ(ffsl(0x10L), 5);
+ ASSERT_EQ(ffsl(0x100L), 9);
+}
+
+} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/test/src/strings/ffsll_test.cpp b/libc/test/src/strings/ffsll_test.cpp
new file mode 100644
index 0000000000000..1888e3161dad6
--- /dev/null
+++ b/libc/test/src/strings/ffsll_test.cpp
@@ -0,0 +1,25 @@
+//===-- Unittests for ffsll -----------------------------------------------===//
+//
+// 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/strings/ffsll.h"
+
+#include "src/__support/macros/config.h"
+#include "test/UnitTest/Test.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+TEST(LlvmLibcFfsllTest, SimpleFfsll) {
+ ASSERT_EQ(ffsll(0LL), 0);
+ ASSERT_EQ(ffsll(1LL), 1);
+ ASSERT_EQ(ffsll(0xfbe71LL), 1);
+ ASSERT_EQ(ffsll(0xfbe70LL), 5);
+ ASSERT_EQ(ffsll(0x10LL), 5);
+ ASSERT_EQ(ffsll(0x100LL), 9);
+}
+
+} // namespace LIBC_NAMESPACE_DECL
``````````
</details>
https://github.com/llvm/llvm-project/pull/129892
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