[libc] Clean up required LIBC_INLINE uses in src/string

This was generated using clang-tidy and clang-apply-replacements,
on src/string/*.cpp for just the llvmlibc-inline-function-decl
check, after applying https://reviews.llvm.org/D157164, and then
some manual fixup.

Reviewed By: abrachet

Differential Revision: https://reviews.llvm.org/D157169

libc/src/__support/CPP/array.h

@@ -9,6 +9,7 @@
 #ifndef LLVM_LIBC_SRC_SUPPORT_CPP_ARRAY_H
 #define LLVM_LIBC_SRC_SUPPORT_CPP_ARRAY_H
 
+#include "src/__support/macros/attributes.h"
 #include <stddef.h> // For size_t.
 
 namespace __llvm_libc {
@@ -22,28 +23,30 @@ template <class T, size_t N> struct array {
   using iterator = T *;
   using const_iterator = const T *;
 
-  constexpr T *data() { return Data; }
-  constexpr const T *data() const { return Data; }
+  LIBC_INLINE constexpr T *data() { return Data; }
+  LIBC_INLINE constexpr const T *data() const { return Data; }
 
-  constexpr T &front() { return Data[0]; }
-  constexpr T &front() const { return Data[0]; }
+  LIBC_INLINE constexpr T &front() { return Data[0]; }
+  LIBC_INLINE constexpr T &front() const { return Data[0]; }
 
-  constexpr T &back() { return Data[N - 1]; }
-  constexpr T &back() const { return Data[N - 1]; }
+  LIBC_INLINE constexpr T &back() { return Data[N - 1]; }
+  LIBC_INLINE constexpr T &back() const { return Data[N - 1]; }
 
-  constexpr T &operator[](size_t Index) { return Data[Index]; }
+  LIBC_INLINE constexpr T &operator[](size_t Index) { return Data[Index]; }
 
-  constexpr const T &operator[](size_t Index) const { return Data[Index]; }
+  LIBC_INLINE constexpr const T &operator[](size_t Index) const {
+    return Data[Index];
+  }
 
-  constexpr size_t size() const { return N; }
+  LIBC_INLINE constexpr size_t size() const { return N; }
 
-  constexpr bool empty() const { return N == 0; }
+  LIBC_INLINE constexpr bool empty() const { return N == 0; }
 
-  constexpr iterator begin() { return Data; }
-  constexpr const_iterator begin() const { return Data; }
+  LIBC_INLINE constexpr iterator begin() { return Data; }
+  LIBC_INLINE constexpr const_iterator begin() const { return Data; }
 
-  constexpr iterator end() { return Data + N; }
-  const_iterator end() const { return Data + N; }
+  LIBC_INLINE constexpr iterator end() { return Data + N; }
+  LIBC_INLINE const_iterator end() const { return Data + N; }
 };
 
 } // namespace cpp

libc/src/__support/CPP/bit.h

@@ -10,6 +10,7 @@
 #define LLVM_LIBC_SUPPORT_CPP_BIT_H
 
 #include "src/__support/CPP/type_traits.h"
+#include "src/__support/macros/attributes.h"
 #include "src/__support/macros/config.h" // LIBC_HAS_BUILTIN
 
 namespace __llvm_libc::cpp {
@@ -24,7 +25,8 @@ namespace __llvm_libc::cpp {
 
 // This function guarantees the bitcast to be optimized away by the compiler for
 // GCC >= 8 and Clang >= 6.
-template <class To, class From> constexpr To bit_cast(const From &from) {
+template <class To, class From>
+LIBC_INLINE constexpr To bit_cast(const From &from) {
   static_assert(sizeof(To) == sizeof(From), "To and From must be of same size");
   static_assert(cpp::is_trivially_copyable<To>::value &&
                     cpp::is_trivially_copyable<From>::value,

libc/src/__support/CPP/bitset.h

@@ -9,6 +9,7 @@
 #ifndef LLVM_LIBC_SRC_SUPPORT_CPP_BITSET_H
 #define LLVM_LIBC_SRC_SUPPORT_CPP_BITSET_H
 
+#include "src/__support/macros/attributes.h"
 #include <stddef.h> // For size_t.
 
 namespace __llvm_libc::cpp {
@@ -17,27 +18,27 @@ template <size_t NumberOfBits> struct bitset {
   static_assert(NumberOfBits != 0,
                 "Cannot create a __llvm_libc::cpp::bitset of size 0.");
 
-  constexpr void set(size_t Index) {
+  LIBC_INLINE constexpr void set(size_t Index) {
     Data[Index / BITS_PER_UNIT] |= mask(Index);
   }
 
-  constexpr void reset() {
+  LIBC_INLINE constexpr void reset() {
     for (size_t i = 0; i < NUMBER_OF_UNITS; ++i)
       Data[i] = 0;
   }
 
-  constexpr bool test(size_t Index) const {
+  LIBC_INLINE constexpr bool test(size_t Index) const {
     return Data[Index / BITS_PER_UNIT] & mask(Index);
   }
 
-  constexpr void flip() {
+  LIBC_INLINE constexpr void flip() {
     for (size_t i = 0; i < NUMBER_OF_UNITS; ++i)
       Data[i] = ~Data[i];
   }
 
   // This function sets all bits in the range from Start to End (inclusive) to
   // true. It assumes that Start <= End.
-  constexpr void set_range(size_t Start, size_t End) {
+  LIBC_INLINE constexpr void set_range(size_t Start, size_t End) {
     size_t start_index = Start / BITS_PER_UNIT;
     size_t end_index = End / BITS_PER_UNIT;
 
@@ -64,7 +65,7 @@ template <size_t NumberOfBits> struct bitset {
     }
   }
 
-  constexpr bool operator==(const bitset<NumberOfBits> &other) {
+  LIBC_INLINE constexpr bool operator==(const bitset<NumberOfBits> &other) {
     for (size_t i = 0; i < NUMBER_OF_UNITS; ++i) {
       if (Data[i] != other.Data[i])
         return false;
@@ -78,7 +79,7 @@ template <size_t NumberOfBits> struct bitset {
   static constexpr size_t NUMBER_OF_UNITS =
       (NumberOfBits + BITS_PER_UNIT - 1) / BITS_PER_UNIT;
 
-  static constexpr size_t mask(size_t Index) {
+  LIBC_INLINE static constexpr size_t mask(size_t Index) {
     return size_t{1} << (Index % BITS_PER_UNIT);
   }
   size_t Data[NUMBER_OF_UNITS] = {0};

libc/src/__support/CPP/cstddef.h

@@ -9,52 +9,59 @@
 #ifndef LLVM_LIBC_SRC_SUPPORT_CPP_BYTE_H
 #define LLVM_LIBC_SRC_SUPPORT_CPP_BYTE_H
 
+#include "src/__support/macros/attributes.h"
 #include "type_traits.h" // For enable_if_t, is_integral_v.
 
 namespace __llvm_libc::cpp {
 
 enum class byte : unsigned char {};
 
 template <class IntegerType>
-constexpr enable_if_t<is_integral_v<IntegerType>, byte>
+LIBC_INLINE constexpr enable_if_t<is_integral_v<IntegerType>, byte>
 operator>>(byte b, IntegerType shift) noexcept {
   return static_cast<byte>(static_cast<unsigned char>(b) >> shift);
 }
 template <class IntegerType>
-constexpr enable_if_t<is_integral_v<IntegerType>, byte &>
+LIBC_INLINE constexpr enable_if_t<is_integral_v<IntegerType>, byte &>
 operator>>=(byte &b, IntegerType shift) noexcept {
   return b = b >> shift;
 }
 template <class IntegerType>
-constexpr enable_if_t<is_integral_v<IntegerType>, byte>
+LIBC_INLINE constexpr enable_if_t<is_integral_v<IntegerType>, byte>
 operator<<(byte b, IntegerType shift) noexcept {
   return static_cast<byte>(static_cast<unsigned char>(b) << shift);
 }
 template <class IntegerType>
-constexpr enable_if_t<is_integral_v<IntegerType>, byte &>
+LIBC_INLINE constexpr enable_if_t<is_integral_v<IntegerType>, byte &>
 operator<<=(byte &b, IntegerType shift) noexcept {
   return b = b << shift;
 }
-constexpr byte operator|(byte l, byte r) noexcept {
+LIBC_INLINE constexpr byte operator|(byte l, byte r) noexcept {
   return static_cast<byte>(static_cast<unsigned char>(l) |
                            static_cast<unsigned char>(r));
 }
-constexpr byte &operator|=(byte &l, byte r) noexcept { return l = l | r; }
-constexpr byte operator&(byte l, byte r) noexcept {
+LIBC_INLINE constexpr byte &operator|=(byte &l, byte r) noexcept {
+  return l = l | r;
+}
+LIBC_INLINE constexpr byte operator&(byte l, byte r) noexcept {
   return static_cast<byte>(static_cast<unsigned char>(l) &
                            static_cast<unsigned char>(r));
 }
-constexpr byte &operator&=(byte &l, byte r) noexcept { return l = l & r; }
-constexpr byte operator^(byte l, byte r) noexcept {
+LIBC_INLINE constexpr byte &operator&=(byte &l, byte r) noexcept {
+  return l = l & r;
+}
+LIBC_INLINE constexpr byte operator^(byte l, byte r) noexcept {
   return static_cast<byte>(static_cast<unsigned char>(l) ^
                            static_cast<unsigned char>(r));
 }
-constexpr byte &operator^=(byte &l, byte r) noexcept { return l = l ^ r; }
-constexpr byte operator~(byte b) noexcept {
+LIBC_INLINE constexpr byte &operator^=(byte &l, byte r) noexcept {
+  return l = l ^ r;
+}
+LIBC_INLINE constexpr byte operator~(byte b) noexcept {
   return static_cast<byte>(~static_cast<unsigned char>(b));
 }
 template <typename IntegerType>
-constexpr enable_if_t<is_integral_v<IntegerType>, IntegerType>
+LIBC_INLINE constexpr enable_if_t<is_integral_v<IntegerType>, IntegerType>
 to_integer(byte b) noexcept {
   return static_cast<IntegerType>(b);
 }

libc/src/__support/CPP/new.h

@@ -27,14 +27,16 @@ namespace __llvm_libc {
 
 class AllocChecker {
   bool success = false;
-  AllocChecker &operator=(bool status) {
+
+  LIBC_INLINE AllocChecker &operator=(bool status) {
     success = status;
     return *this;
   }
 
 public:
-  AllocChecker() = default;
-  operator bool() const { return success; }
+  LIBC_INLINE AllocChecker() = default;
+
+  LIBC_INLINE operator bool() const { return success; }
 
   LIBC_INLINE static void *alloc(size_t s, AllocChecker &ac) {
     void *mem = ::malloc(s);

libc/src/__support/CPP/optional.h

@@ -18,12 +18,12 @@ namespace cpp {
 
 // Trivial in_place_t struct.
 struct in_place_t {
-  LIBC_INLINE_VAR explicit in_place_t() = default;
+  LIBC_INLINE constexpr explicit in_place_t() = default;
 };
 
 // Trivial nullopt_t struct.
 struct nullopt_t {
-  LIBC_INLINE_VAR explicit nullopt_t() = default;
+  LIBC_INLINE constexpr explicit nullopt_t() = default;
 };
 
 // nullopt that can be used and returned.

libc/src/__support/CPP/span.h

@@ -46,7 +46,7 @@ template <typename T> class span {
   using const_reference = const T &;
   using iterator = T *;
 
-  static constexpr size_type dynamic_extent = -1;
+  LIBC_INLINE_VAR static constexpr size_type dynamic_extent = -1;
 
   LIBC_INLINE constexpr span() : span_data(nullptr), span_size(0) {}
 

libc/src/__support/CPP/string_view.h

@@ -26,7 +26,7 @@ class string_view {
   const char *Data;
   size_t Len;
 
-  static size_t min(size_t A, size_t B) { return A <= B ? A : B; }
+  LIBC_INLINE static size_t min(size_t A, size_t B) { return A <= B ? A : B; }
 
   LIBC_INLINE static int compareMemory(const char *Lhs, const char *Rhs,
                                        size_t Length) {

libc/src/__support/CPP/type_traits.h

@@ -68,7 +68,8 @@ template <typename T> struct remove_cvref {
 template <typename T> using remove_cvref_t = typename remove_cvref<T>::type;
 
 namespace details {
-template <typename T, typename... Args> constexpr bool is_unqualified_any_of() {
+template <typename T, typename... Args>
+LIBC_INLINE constexpr bool is_unqualified_any_of() {
   return (... || is_same_v<remove_cv_t<T>, Args>);
 }
 } // namespace details

libc/src/__support/common.h

@@ -39,7 +39,7 @@
 
 namespace __llvm_libc {
 namespace internal {
-constexpr bool same_string(char const *lhs, char const *rhs) {
+LIBC_INLINE constexpr bool same_string(char const *lhs, char const *rhs) {
   for (; *lhs || *rhs; ++lhs, ++rhs)
     if (*lhs != *rhs)
       return false;

libc/src/__support/ctype_utils.h

@@ -9,6 +9,8 @@
 #ifndef LLVM_LIBC_SRC_SUPPORT_CTYPE_UTILS_H
 #define LLVM_LIBC_SRC_SUPPORT_CTYPE_UTILS_H
 
+#include "src/__support/macros/attributes.h"
+
 namespace __llvm_libc {
 namespace internal {
 
@@ -18,25 +20,35 @@ namespace internal {
 // of a function call by inlining them.
 // ------------------------------------------------------
 
-static constexpr bool isalpha(unsigned ch) { return (ch | 32) - 'a' < 26; }
+LIBC_INLINE static constexpr bool isalpha(unsigned ch) {
+  return (ch | 32) - 'a' < 26;
+}
 
-static constexpr bool isdigit(unsigned ch) { return (ch - '0') < 10; }
+LIBC_INLINE static constexpr bool isdigit(unsigned ch) {
+  return (ch - '0') < 10;
+}
 
-static constexpr bool isalnum(unsigned ch) {
+LIBC_INLINE static constexpr bool isalnum(unsigned ch) {
   return isalpha(ch) || isdigit(ch);
 }
 
-static constexpr bool isgraph(unsigned ch) { return 0x20 < ch && ch < 0x7f; }
+LIBC_INLINE static constexpr bool isgraph(unsigned ch) {
+  return 0x20 < ch && ch < 0x7f;
+}
 
-static constexpr bool islower(unsigned ch) { return (ch - 'a') < 26; }
+LIBC_INLINE static constexpr bool islower(unsigned ch) {
+  return (ch - 'a') < 26;
+}
 
-static constexpr bool isupper(unsigned ch) { return (ch - 'A') < 26; }
+LIBC_INLINE static constexpr bool isupper(unsigned ch) {
+  return (ch - 'A') < 26;
+}
 
-static constexpr bool isspace(unsigned ch) {
+LIBC_INLINE static constexpr bool isspace(unsigned ch) {
   return ch == ' ' || (ch - '\t') < 5;
 }
 
-static constexpr int tolower(int ch) {
+LIBC_INLINE static constexpr int tolower(int ch) {
   if (isupper(ch))
     return ch + ('a' - 'A');
   return ch;

libc/src/string/memory_utils/inline_memmem.h

@@ -9,14 +9,16 @@
 #ifndef LLVM_LIBC_SRC_STRING_MEMORY_UTILS_INLINE_MEMMEM_H
 #define LLVM_LIBC_SRC_STRING_MEMORY_UTILS_INLINE_MEMMEM_H
 
+#include "src/__support/macros/attributes.h"
+
 #include <stddef.h>
 
 namespace __llvm_libc {
 
 template <typename Comp>
-constexpr static void *inline_memmem(const void *haystack, size_t haystack_len,
-                                     const void *needle, size_t needle_len,
-                                     Comp &&comp) {
+LIBC_INLINE constexpr static void *
+inline_memmem(const void *haystack, size_t haystack_len, const void *needle,
+              size_t needle_len, Comp &&comp) {
   // TODO: simple brute force implementation. This can be
   // improved upon using well known string matching algorithms.
   if (!needle_len)