[libc] implement stdc_leading_zeros_u* for stdbit.h

- stdbit.stdc_leading_zeros_uc
- stdbit.stdc_leading_zeros_us
- stdbit.stdc_leading_zeros_ui
- stdbit.stdc_leading_zeros_ul
- stdbit.stdc_leading_zeros_ull

Test via:
$ ninja libc-stdbit-tests libc_include_tests

Author: nickdesaulniers

libc/config/linux/x86_64/entrypoints.txt

@@ -91,6 +91,13 @@ set(TARGET_LIBC_ENTRYPOINTS
     libc.src.inttypes.strtoimax
     libc.src.inttypes.strtoumax
 
+    # stdbit.h entrypoints
+    libc.src.stdbit.stdc_leading_zeros_uc
+    libc.src.stdbit.stdc_leading_zeros_us
+    libc.src.stdbit.stdc_leading_zeros_ui
+    libc.src.stdbit.stdc_leading_zeros_ul
+    libc.src.stdbit.stdc_leading_zeros_ull
+
     # stdlib.h entrypoints
     libc.src.stdlib.abs
     libc.src.stdlib.atoi

libc/config/linux/x86_64/headers.txt

@@ -15,6 +15,7 @@ set(TARGET_PUBLIC_HEADERS
     libc.include.signal
     libc.include.spawn
     libc.include.setjmp
+    libc.include.stdbit
     libc.include.stdio
     libc.include.stdlib
     libc.include.string

libc/include/CMakeLists.txt

@@ -223,6 +223,15 @@ else()
   message(STATUS "Skipping header signal.h as the target config is missing")
 endif()
 
+add_gen_header(
+  stdbit
+  DEF_FILE stdbit.h.def
+  GEN_HDR stdbit.h
+  DEPENDS
+    .llvm_libc_common_h
+    .llvm-libc-macros.stdbit_macros
+)
+
 add_gen_header(
   stdio
   DEF_FILE stdio.h.def

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

@@ -111,6 +111,12 @@ add_macro_header(
     signal-macros.h
 )
 
+add_macro_header(
+  stdbit_macros
+  HDR
+    stdbit-macros.h
+)
+
 add_macro_header(
   stdio_macros
   HDR

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

@@ -0,0 +1,19 @@
+//===-- Definition of macros to be used with stdbit functions ----------===//
+//
+// 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_STDBIT_MACROS_H
+#define __LLVM_LIBC_MACROS_STDBIT_MACROS_H
+
+#define stdc_leading_zeros(x) _Generic((x), \
+  unsigned char: stdc_leading_zeros_uc, \
+  unsigned short: stdc_leading_zeros_us, \
+  unsigned: stdc_leading_zeros_ui, \
+  unsigned long: stdc_leading_zeros_ul, \
+  unsigned long long: stdc_leading_zeros_ull)(x)
+
+#endif // __LLVM_LIBC_MACROS_STDBIT_MACROS_H

libc/include/stdbit.h.def

@@ -0,0 +1,17 @@
+//===-- C standard library header stdbit.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_STDBIT_H
+#define LLVM_LIBC_STDBIT_H
+
+#include <__llvm-libc-common.h>
+#include <llvm-libc-macros/stdbit-macros.h>
+
+%%public_api()
+
+#endif // LLVM_LIBC_STDBIT_H

libc/spec/spec.td

@@ -50,6 +50,7 @@ def DoubleType : NamedType<"double">;
 def LongDoubleType : NamedType<"long double">;
 def CharType : NamedType<"char">;
 def UnsignedCharType : NamedType<"unsigned char">;
+def UnsignedShortType : NamedType<"unsigned short">;
 
 // TODO: Add compatibility layer to use C23 type _Float128 if possible.
 def Float128Type : NamedType<"__float128">;

libc/spec/stdc.td

@@ -767,6 +767,22 @@ def StdC : StandardSpec<"stdc"> {
       ]
   >;
 
+  HeaderSpec StdBit = HeaderSpec<
+      "stdbit.h",
+      [
+        Macro<"stdc_leading_zeros">
+      ], // Macros
+      [], // Types
+      [], // Enumerations
+      [
+          FunctionSpec<"stdc_leading_zeros_uc", RetValSpec<UnsignedCharType>, [ArgSpec<UnsignedCharType>]>,
+          FunctionSpec<"stdc_leading_zeros_us", RetValSpec<UnsignedShortType>, [ArgSpec<UnsignedShortType>]>,
+          FunctionSpec<"stdc_leading_zeros_ui", RetValSpec<UnsignedIntType>, [ArgSpec<UnsignedIntType>]>,
+          FunctionSpec<"stdc_leading_zeros_ul", RetValSpec<UnsignedLongType>, [ArgSpec<UnsignedLongType>]>,
+          FunctionSpec<"stdc_leading_zeros_ull", RetValSpec<UnsignedLongLongType>, [ArgSpec<UnsignedLongLongType>]>
+      ] // Functions
+  >;
+
   HeaderSpec StdLib = HeaderSpec<
       "stdlib.h",
       [], // Macros
@@ -1141,7 +1157,7 @@ def StdC : StandardSpec<"stdc"> {
       "wchar.h",
       [ // Macros
         Macro<"WEOF">,
-      ], 
+      ],
       [ //Types
         SizeTType,
         WIntType,
@@ -1167,6 +1183,7 @@ def StdC : StandardSpec<"stdc"> {
     Limits,
     Math,
     String,
+    StdBit,
     StdIO,
     StdLib,
     IntTypes,

libc/src/CMakeLists.txt

@@ -5,9 +5,10 @@ add_subdirectory(errno)
 add_subdirectory(fenv)
 add_subdirectory(inttypes)
 add_subdirectory(math)
-add_subdirectory(string)
-add_subdirectory(stdlib)
+add_subdirectory(stdbit)
 add_subdirectory(stdio)
+add_subdirectory(stdlib)
+add_subdirectory(string)
 add_subdirectory(wchar)
 
 if(${LIBC_TARGET_OS} STREQUAL "linux")

libc/src/stdbit/CMakeLists.txt

@@ -0,0 +1,39 @@
+add_entrypoint_object(
+  stdc_leading_zeros_uc
+  SRCS
+    stdc_leading_zeros_uc.cpp
+  HDRS
+    stdc_leading_zeros_uc.h
+)
+
+add_entrypoint_object(
+  stdc_leading_zeros_us
+  SRCS
+    stdc_leading_zeros_us.cpp
+  HDRS
+    stdc_leading_zeros_us.h
+)
+
+add_entrypoint_object(
+  stdc_leading_zeros_ui
+  SRCS
+    stdc_leading_zeros_ui.cpp
+  HDRS
+    stdc_leading_zeros_ui.h
+)
+
+add_entrypoint_object(
+  stdc_leading_zeros_ul
+  SRCS
+    stdc_leading_zeros_ul.cpp
+  HDRS
+    stdc_leading_zeros_ul.h
+)
+
+add_entrypoint_object(
+  stdc_leading_zeros_ull
+  SRCS
+    stdc_leading_zeros_ull.cpp
+  HDRS
+    stdc_leading_zeros_ull.h
+)

libc/src/stdbit/stdc_leading_zeros_uc.cpp

@@ -0,0 +1,20 @@
+//===-- Implementation of stdc_leading_zeros_uc ---------------------------===//
+//
+// 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/stdbit/stdc_leading_zeros_uc.h"
+
+#include "src/__support/CPP/bit.h"
+#include "src/__support/common.h"
+
+namespace LIBC_NAMESPACE {
+
+LLVM_LIBC_FUNCTION(unsigned char, stdc_leading_zeros_uc, (unsigned char value)) {
+  return static_cast<unsigned char>(cpp::countl_zero(value));
+}
+
+} // namespace LIBC_NAMESPACE

libc/src/stdbit/stdc_leading_zeros_uc.h

@@ -0,0 +1,18 @@
+//===-- Implementation header for stdc_leading_zeros_uc ---------*- 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_STDBIT_STDC_LEADING_ZEROS_UC_H
+#define LLVM_LIBC_SRC_STDBIT_STDC_LEADING_ZEROS_UC_H
+
+namespace LIBC_NAMESPACE {
+
+unsigned char stdc_leading_zeros_uc(unsigned char value);
+
+} // namespace LIBC_NAMESPACE
+
+#endif // LLVM_LIBC_SRC_STDBIT_STDC_LEADING_ZEROS_UC_H

libc/src/stdbit/stdc_leading_zeros_ui.cpp

@@ -0,0 +1,20 @@
+//===-- Implementation of stdc_leading_zeros_ui ---------------------------===//
+//
+// 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/stdbit/stdc_leading_zeros_ui.h"
+
+#include "src/__support/CPP/bit.h"
+#include "src/__support/common.h"
+
+namespace LIBC_NAMESPACE {
+
+LLVM_LIBC_FUNCTION(unsigned, stdc_leading_zeros_ui, (unsigned value)) {
+  return static_cast<unsigned>(cpp::countl_zero(value));
+}
+
+} // namespace LIBC_NAMESPACE

libc/src/stdbit/stdc_leading_zeros_ui.h

@@ -0,0 +1,18 @@
+//===-- Implementation header for stdc_leading_zeros_ui ---------*- 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_STDBIT_STDC_LEADING_ZEROS_UI_H
+#define LLVM_LIBC_SRC_STDBIT_STDC_LEADING_ZEROS_UI_H
+
+namespace LIBC_NAMESPACE {
+
+unsigned stdc_leading_zeros_ui(unsigned value);
+
+} // namespace LIBC_NAMESPACE
+
+#endif // LLVM_LIBC_SRC_STDBIT_STDC_LEADING_ZEROS_UI_H

libc/src/stdbit/stdc_leading_zeros_ul.cpp

@@ -0,0 +1,20 @@
+//===-- Implementation of stdc_leading_zeros_ul ---------------------------===//
+//
+// 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/stdbit/stdc_leading_zeros_ul.h"
+
+#include "src/__support/CPP/bit.h"
+#include "src/__support/common.h"
+
+namespace LIBC_NAMESPACE {
+
+LLVM_LIBC_FUNCTION(unsigned long, stdc_leading_zeros_ul, (unsigned long value)) {
+  return static_cast<unsigned long>(cpp::countl_zero(value));
+}
+
+} // namespace LIBC_NAMESPACE

libc/src/stdbit/stdc_leading_zeros_ul.h

@@ -0,0 +1,18 @@
+//===-- Implementation header for stdc_leading_zeros_ul ---------*- 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_STDBIT_STDC_LEADING_ZEROS_UL_H
+#define LLVM_LIBC_SRC_STDBIT_STDC_LEADING_ZEROS_UL_H
+
+namespace LIBC_NAMESPACE {
+
+unsigned long stdc_leading_zeros_ul(unsigned long value);
+
+} // namespace LIBC_NAMESPACE
+
+#endif // LLVM_LIBC_SRC_STDBIT_STDC_LEADING_ZEROS_UL_H

libc/src/stdbit/stdc_leading_zeros_ull.cpp

@@ -0,0 +1,20 @@
+//===-- Implementation of stdc_leading_zeros_ull --------------------------===//
+//
+// 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/stdbit/stdc_leading_zeros_ull.h"
+
+#include "src/__support/CPP/bit.h"
+#include "src/__support/common.h"
+
+namespace LIBC_NAMESPACE {
+
+LLVM_LIBC_FUNCTION(unsigned long long, stdc_leading_zeros_ull, (unsigned long long value)) {
+  return static_cast<unsigned long long>(cpp::countl_zero(value));
+}
+
+} // namespace LIBC_NAMESPACE

libc/src/stdbit/stdc_leading_zeros_ull.h

@@ -0,0 +1,18 @@
+//===-- Implementation header for stdc_leading_zeros_ull --------*- 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_STDBIT_STDC_LEADING_ZEROS_ULL_H
+#define LLVM_LIBC_SRC_STDBIT_STDC_LEADING_ZEROS_ULL_H
+
+namespace LIBC_NAMESPACE {
+
+unsigned long long stdc_leading_zeros_ull(unsigned long long value);
+
+} // namespace LIBC_NAMESPACE
+
+#endif // LLVM_LIBC_SRC_STDBIT_STDC_LEADING_ZEROS_ULL_H

libc/src/stdbit/stdc_leading_zeros_us.cpp

@@ -0,0 +1,20 @@
+//===-- Implementation of stdc_leading_zeros_us ---------------------------===//
+//
+// 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/stdbit/stdc_leading_zeros_us.h"
+
+#include "src/__support/CPP/bit.h"
+#include "src/__support/common.h"
+
+namespace LIBC_NAMESPACE {
+
+LLVM_LIBC_FUNCTION(unsigned short, stdc_leading_zeros_us, (unsigned short value)) {
+  return static_cast<unsigned short>(cpp::countl_zero(value));
+}
+
+} // namespace LIBC_NAMESPACE

libc/src/stdbit/stdc_leading_zeros_us.h

@@ -0,0 +1,18 @@
+//===-- Implementation header for stdc_leading_zeros_us ---------*- 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_STDBIT_STDC_LEADING_ZEROS_US_H
+#define LLVM_LIBC_SRC_STDBIT_STDC_LEADING_ZEROS_US_H
+
+namespace LIBC_NAMESPACE {
+
+unsigned short stdc_leading_zeros_us(unsigned short value);
+
+} // namespace LIBC_NAMESPACE
+
+#endif // LLVM_LIBC_SRC_STDBIT_STDC_LEADING_ZEROS_US_H