Address comments

Author: Sterling-Augustine

libc/src/string/memory_utils/aarch64/inline_strlen.h

@@ -15,7 +15,9 @@
 #include <stddef.h> // size_t
 
 namespace LIBC_NAMESPACE_DECL {
-[[maybe_unused]] LIBC_INLINE size_t string_length_neon(const char *src) {
+
+namespace neon {
+[[maybe_unused]] LIBC_INLINE size_t string_length(const char *src) {
   using Vector __attribute__((may_alias)) = uint8x8_t;
 
   uintptr_t misalign_bytes = reinterpret_cast<uintptr_t>(src) % sizeof(Vector);
@@ -40,12 +42,10 @@ namespace LIBC_NAMESPACE_DECL {
                                  (cpp::countr_zero(cmp) >> 3));
   }
 }
+}  // namespace neon
 
-template <typename T>
-[[maybe_unused]] LIBC_INLINE void string_length_aarch64(const char *src) {
-  return inline_string_length_neon(src);
-}
-} // namespace LIBC_NAMESPACE_DECL
+namespace string_length_impl = neon;
 
+}  // namespace LIBC_NAMESPACE_DECL
 #endif // __ARM_NEON
 #endif // LLVM_LIBC_SRC_STRING_MEMORY_UTILS_AARCH64_INLINE_STRLEN_H

libc/src/string/memory_utils/x86_64/inline_strlen.h

@@ -9,13 +9,14 @@
 #define LLVM_LIBC_SRC_STRING_MEMORY_UTILS_X86_64_INLINE_STRLEN_H
 
 #include "src/__support/CPP/bit.h"          // countr_zero
-#include "src/string/memory_utils/op_x86.h" // K_AVX
 
+#include <immintrin.h>
 #include <stddef.h> // size_t
 
 namespace LIBC_NAMESPACE_DECL {
 
-[[maybe_unused]] LIBC_INLINE size_t string_length_sse2(const char *src) {
+namespace sse2 {
+[[maybe_unused]] LIBC_INLINE size_t string_length(const char *src) {
   using Vector __attribute__((may_alias)) = __m128i;
 
   Vector z = _mm_setzero_si128();
@@ -40,9 +41,11 @@ namespace LIBC_NAMESPACE_DECL {
                                  cpp::countr_zero(cmp));
   }
 }
+}  // namespace sse2
 
 #if defined(__AVX2__)
-[[maybe_unused]] LIBC_INLINE size_t string_length_avx2(const char *src) {
+namespace avx2 {
+[[maybe_unused]] LIBC_INLINE size_t string_length(const char *src) {
   using Vector __attribute__((may_alias)) = __mm256i;
 
   Vector z = _mm256_setzero_si256();
@@ -67,10 +70,12 @@ namespace LIBC_NAMESPACE_DECL {
                                  cpp::countr_zero(cmp));
   }
 }
-#endif // __AVX2__
+}
+#endif
 
 #if defined(__AVX512F__)
-[[maybe_unused]] LIBC_INLINE size_t string_length_avx512(const char *src) {
+namespace avx512 {
+[[maybe_unused]] LIBC_INLINE size_t string_length(const char *src) {
   using Vector __attribute__((may_alias)) = __mm512i;
 
   Vector z = _mm512_setzero_si512();
@@ -92,18 +97,16 @@ namespace LIBC_NAMESPACE_DECL {
                                  cpp::countr_zero(cmp));
   }
 }
-#endif // __AVX512F__
+} // namespace avx512
+#endif
 
-namespace x86 {
-template <typename T> LIBC_INLINE size_t string_length_x86_64(const char *src) {
 #if defined(__AVX512F__)
-  return string_length_avx512(src);
+namespace string_length_impl = avx512;
 #elif defined(__AVX2__)
-  return string_length_avx2(src);
+namespace string_length_impl = avx2;
+#else
+namespace string_length_impl = sse2;
 #endif
-  return string_length_sse2(src);
-}
-}
 
 } // namespace LIBC_NAMESPACE_DECL
 

libc/src/string/string_utils.h

@@ -25,12 +25,10 @@
 #if defined(LIBC_COPT_STRING_UNSAFE_WIDE_READ)
 #if defined(LIBC_TARGET_ARCH_IS_X86)
 #include "src/string/memory_utils/x86_64/inline_strlen.h"
-namespace wide_read_impl = x86;
 #elif defined(LIBC_TARGET_ARCH_IS_AARCH64) && defined(__ARM_NEON)
 #include "src/string/memory_utils/aarch64/inline_strlen.h"
-namespace wide_read_impl = aarch64;
 #else
-namespace wide_read_impl = default_wide_read;
+namespace string_length_impl = LIBC_NAMESPACE::wide_read;
 #endif
 #endif
 
@@ -72,7 +70,6 @@ template <typename Word> LIBC_INLINE constexpr bool has_zeroes(Word block) {
   return (subtracted & inverted & HIGH_BITS) != 0;
 }
 
-namespace default_wide_read {
 template <typename Word>
 LIBC_INLINE size_t string_length_wide_read(const char *src) {
   const char *char_ptr = src;
@@ -93,18 +90,24 @@ LIBC_INLINE size_t string_length_wide_read(const char *src) {
   }
   return static_cast<size_t>(char_ptr - src);
 }
-} // namespace default_wide_read
 
-// Returns the length of a string, denoted by the first occurrence
-// of a null terminator.
-template <typename T> LIBC_INLINE size_t string_length(const T *src) {
-#ifdef LIBC_COPT_STRING_UNSAFE_WIDE_READ
+namespace wide_read {
+LIBC_INLINE size_t string_length(const char *src) {
   // Unsigned int is the default size for most processors, and on x86-64 it
   // performs better than larger sizes when the src pointer can't be assumed to
   // be aligned to a word boundary, so it's the size we use for reading the
   // string a block at a time.
+  return string_length_wide_read<unsigned int>(src);
+}
+
+} // namespace wide_read
+
+// Returns the length of a string, denoted by the first occurrence
+// of a null terminator.
+template <typename T> LIBC_INLINE size_t string_length(const T *src) {
+#ifdef LIBC_COPT_STRING_UNSAFE_WIDE_READ
   if constexpr (cpp::is_same_v<T, char>)
-    return wide_read_impl::string_length(src);
+    return string_length_impl::string_length(src);
 #endif
   size_t length;
   for (length = 0; *src; ++src, ++length)