[libcxx-commits] [libcxx] dea7a8e - [libc++] Don't use static constexpr in headers.

Mark de Wever via libcxx-commits libcxx-commits at lists.llvm.org
Tue Jun 7 09:47:49 PDT 2022


Author: Mark de Wever
Date: 2022-06-07T18:47:44+02:00
New Revision: dea7a8e616daca3d487470cd9f648e94470f1afc

URL: https://github.com/llvm/llvm-project/commit/dea7a8e616daca3d487470cd9f648e94470f1afc
DIFF: https://github.com/llvm/llvm-project/commit/dea7a8e616daca3d487470cd9f648e94470f1afc.diff

LOG: [libc++] Don't use static constexpr in headers.

This was noticed in the review of D125704. In that commit only the new
table has been adapted. This adapts the existing tables.

Note since libc++'s charconv is backported to C++11 it's not possible to
use inline constexpr variables. The were introduced in C++17.

Reviewed By: #libc, ldionne

Differential Revision: https://reviews.llvm.org/D126887

Added: 
    

Modified: 
    libcxx/include/__charconv/tables.h
    libcxx/include/__charconv/to_chars_base_10.h
    libcxx/include/charconv
    libcxx/src/include/ryu/digit_table.h

Removed: 
    


################################################################################
diff  --git a/libcxx/include/__charconv/tables.h b/libcxx/include/__charconv/tables.h
index c9cceee825f24..a2f7f7ce29b37 100644
--- a/libcxx/include/__charconv/tables.h
+++ b/libcxx/include/__charconv/tables.h
@@ -11,6 +11,7 @@
 #define _LIBCPP___CHARCONV_TABLES
 
 #include <__config>
+#include <cstdint>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
@@ -22,13 +23,91 @@ _LIBCPP_BEGIN_NAMESPACE_STD
 
 namespace __itoa {
 
+/// Contains the charconv helper tables.
+///
+/// In C++17 these could be inline constexpr variable, but libc++ supports
+/// charconv for integrals in C++11 mode.
 template <class = void>
-struct __digits_base_10 {
-  static const char __value[200];
+struct __table {
+  static const char __base_2_lut[64];
+  static const char __base_8_lut[128];
+  static const char __base_16_lut[512];
+
+  static const uint32_t __pow10_32[10];
+  static const uint64_t __pow10_64[20];
+  static const char __digits_base_10[200];
 };
 
 template <class _Tp>
-const char __digits_base_10<_Tp>::__value[200] = {
+const char __table<_Tp>::__base_2_lut[64] = {
+    '0', '0', '0', '0', '0', '0', '0', '1', '0', '0', '1', '0', '0', '0', '1', '1', '0', '1', '0', '0', '0', '1',
+    '0', '1', '0', '1', '1', '0', '0', '1', '1', '1', '1', '0', '0', '0', '1', '0', '0', '1', '1', '0', '1', '0',
+    '1', '0', '1', '1', '1', '1', '0', '0', '1', '1', '0', '1', '1', '1', '1', '0', '1', '1', '1', '1'};
+
+template <class _Tp>
+const char __table<_Tp>::__base_8_lut[128] = {
+    '0', '0', '0', '1', '0', '2', '0', '3', '0', '4', '0', '5', '0', '6', '0', '7', '1', '0', '1', '1', '1', '2',
+    '1', '3', '1', '4', '1', '5', '1', '6', '1', '7', '2', '0', '2', '1', '2', '2', '2', '3', '2', '4', '2', '5',
+    '2', '6', '2', '7', '3', '0', '3', '1', '3', '2', '3', '3', '3', '4', '3', '5', '3', '6', '3', '7', '4', '0',
+    '4', '1', '4', '2', '4', '3', '4', '4', '4', '5', '4', '6', '4', '7', '5', '0', '5', '1', '5', '2', '5', '3',
+    '5', '4', '5', '5', '5', '6', '5', '7', '6', '0', '6', '1', '6', '2', '6', '3', '6', '4', '6', '5', '6', '6',
+    '6', '7', '7', '0', '7', '1', '7', '2', '7', '3', '7', '4', '7', '5', '7', '6', '7', '7'};
+
+template <class _Tp>
+const char __table<_Tp>::__base_16_lut[512] = {
+    '0', '0', '0', '1', '0', '2', '0', '3', '0', '4', '0', '5', '0', '6', '0', '7', '0', '8', '0', '9', '0', 'a', '0',
+    'b', '0', 'c', '0', 'd', '0', 'e', '0', 'f', '1', '0', '1', '1', '1', '2', '1', '3', '1', '4', '1', '5', '1', '6',
+    '1', '7', '1', '8', '1', '9', '1', 'a', '1', 'b', '1', 'c', '1', 'd', '1', 'e', '1', 'f', '2', '0', '2', '1', '2',
+    '2', '2', '3', '2', '4', '2', '5', '2', '6', '2', '7', '2', '8', '2', '9', '2', 'a', '2', 'b', '2', 'c', '2', 'd',
+    '2', 'e', '2', 'f', '3', '0', '3', '1', '3', '2', '3', '3', '3', '4', '3', '5', '3', '6', '3', '7', '3', '8', '3',
+    '9', '3', 'a', '3', 'b', '3', 'c', '3', 'd', '3', 'e', '3', 'f', '4', '0', '4', '1', '4', '2', '4', '3', '4', '4',
+    '4', '5', '4', '6', '4', '7', '4', '8', '4', '9', '4', 'a', '4', 'b', '4', 'c', '4', 'd', '4', 'e', '4', 'f', '5',
+    '0', '5', '1', '5', '2', '5', '3', '5', '4', '5', '5', '5', '6', '5', '7', '5', '8', '5', '9', '5', 'a', '5', 'b',
+    '5', 'c', '5', 'd', '5', 'e', '5', 'f', '6', '0', '6', '1', '6', '2', '6', '3', '6', '4', '6', '5', '6', '6', '6',
+    '7', '6', '8', '6', '9', '6', 'a', '6', 'b', '6', 'c', '6', 'd', '6', 'e', '6', 'f', '7', '0', '7', '1', '7', '2',
+    '7', '3', '7', '4', '7', '5', '7', '6', '7', '7', '7', '8', '7', '9', '7', 'a', '7', 'b', '7', 'c', '7', 'd', '7',
+    'e', '7', 'f', '8', '0', '8', '1', '8', '2', '8', '3', '8', '4', '8', '5', '8', '6', '8', '7', '8', '8', '8', '9',
+    '8', 'a', '8', 'b', '8', 'c', '8', 'd', '8', 'e', '8', 'f', '9', '0', '9', '1', '9', '2', '9', '3', '9', '4', '9',
+    '5', '9', '6', '9', '7', '9', '8', '9', '9', '9', 'a', '9', 'b', '9', 'c', '9', 'd', '9', 'e', '9', 'f', 'a', '0',
+    'a', '1', 'a', '2', 'a', '3', 'a', '4', 'a', '5', 'a', '6', 'a', '7', 'a', '8', 'a', '9', 'a', 'a', 'a', 'b', 'a',
+    'c', 'a', 'd', 'a', 'e', 'a', 'f', 'b', '0', 'b', '1', 'b', '2', 'b', '3', 'b', '4', 'b', '5', 'b', '6', 'b', '7',
+    'b', '8', 'b', '9', 'b', 'a', 'b', 'b', 'b', 'c', 'b', 'd', 'b', 'e', 'b', 'f', 'c', '0', 'c', '1', 'c', '2', 'c',
+    '3', 'c', '4', 'c', '5', 'c', '6', 'c', '7', 'c', '8', 'c', '9', 'c', 'a', 'c', 'b', 'c', 'c', 'c', 'd', 'c', 'e',
+    'c', 'f', 'd', '0', 'd', '1', 'd', '2', 'd', '3', 'd', '4', 'd', '5', 'd', '6', 'd', '7', 'd', '8', 'd', '9', 'd',
+    'a', 'd', 'b', 'd', 'c', 'd', 'd', 'd', 'e', 'd', 'f', 'e', '0', 'e', '1', 'e', '2', 'e', '3', 'e', '4', 'e', '5',
+    'e', '6', 'e', '7', 'e', '8', 'e', '9', 'e', 'a', 'e', 'b', 'e', 'c', 'e', 'd', 'e', 'e', 'e', 'f', 'f', '0', 'f',
+    '1', 'f', '2', 'f', '3', 'f', '4', 'f', '5', 'f', '6', 'f', '7', 'f', '8', 'f', '9', 'f', 'a', 'f', 'b', 'f', 'c',
+    'f', 'd', 'f', 'e', 'f', 'f'};
+
+template <class _Tp>
+const uint32_t __table<_Tp>::__pow10_32[10] = {
+    UINT32_C(0),      UINT32_C(10),      UINT32_C(100),      UINT32_C(1000),      UINT32_C(10000),
+    UINT32_C(100000), UINT32_C(1000000), UINT32_C(10000000), UINT32_C(100000000), UINT32_C(1000000000)};
+
+template <class _Tp>
+const uint64_t __table<_Tp>::__pow10_64[20] = {UINT64_C(0),
+                                               UINT64_C(10),
+                                               UINT64_C(100),
+                                               UINT64_C(1000),
+                                               UINT64_C(10000),
+                                               UINT64_C(100000),
+                                               UINT64_C(1000000),
+                                               UINT64_C(10000000),
+                                               UINT64_C(100000000),
+                                               UINT64_C(1000000000),
+                                               UINT64_C(10000000000),
+                                               UINT64_C(100000000000),
+                                               UINT64_C(1000000000000),
+                                               UINT64_C(10000000000000),
+                                               UINT64_C(100000000000000),
+                                               UINT64_C(1000000000000000),
+                                               UINT64_C(10000000000000000),
+                                               UINT64_C(100000000000000000),
+                                               UINT64_C(1000000000000000000),
+                                               UINT64_C(10000000000000000000)};
+
+template <class _Tp>
+const char __table<_Tp>::__digits_base_10[200] = {
     // clang-format off
     '0', '0', '0', '1', '0', '2', '0', '3', '0', '4', '0', '5', '0', '6', '0', '7', '0', '8', '0', '9',
     '1', '0', '1', '1', '1', '2', '1', '3', '1', '4', '1', '5', '1', '6', '1', '7', '1', '8', '1', '9',

diff  --git a/libcxx/include/__charconv/to_chars_base_10.h b/libcxx/include/__charconv/to_chars_base_10.h
index 3f689ec1050f9..1c6804a852460 100644
--- a/libcxx/include/__charconv/to_chars_base_10.h
+++ b/libcxx/include/__charconv/to_chars_base_10.h
@@ -33,7 +33,7 @@ _LIBCPP_HIDE_FROM_ABI char* __append1(char* __buffer, _Tp __value) noexcept {
 
 template <class _Tp>
 _LIBCPP_HIDE_FROM_ABI char* __append2(char* __buffer, _Tp __value) noexcept {
-  std::memcpy(__buffer, &__digits_base_10<>::__value[(__value)*2], 2);
+  std::memcpy(__buffer, &__table<>::__digits_base_10[(__value)*2], 2);
   return __buffer + 2;
 }
 

diff  --git a/libcxx/include/charconv b/libcxx/include/charconv
index 8b80d5b07b36f..96440e10c2c15 100644
--- a/libcxx/include/charconv
+++ b/libcxx/include/charconv
@@ -113,35 +113,6 @@ from_chars_result from_chars(const char*, const char*, bool, int = 10) = delete;
 namespace __itoa
 {
 
-static constexpr uint64_t __pow10_64[] = {
-    UINT64_C(0),
-    UINT64_C(10),
-    UINT64_C(100),
-    UINT64_C(1000),
-    UINT64_C(10000),
-    UINT64_C(100000),
-    UINT64_C(1000000),
-    UINT64_C(10000000),
-    UINT64_C(100000000),
-    UINT64_C(1000000000),
-    UINT64_C(10000000000),
-    UINT64_C(100000000000),
-    UINT64_C(1000000000000),
-    UINT64_C(10000000000000),
-    UINT64_C(100000000000000),
-    UINT64_C(1000000000000000),
-    UINT64_C(10000000000000000),
-    UINT64_C(100000000000000000),
-    UINT64_C(1000000000000000000),
-    UINT64_C(10000000000000000000),
-};
-
-static constexpr uint32_t __pow10_32[] = {
-    UINT32_C(0),          UINT32_C(10),       UINT32_C(100),
-    UINT32_C(1000),       UINT32_C(10000),    UINT32_C(100000),
-    UINT32_C(1000000),    UINT32_C(10000000), UINT32_C(100000000),
-    UINT32_C(1000000000),
-};
 
 template <typename _Tp, typename = void>
 struct _LIBCPP_HIDDEN __traits_base
@@ -151,7 +122,7 @@ struct _LIBCPP_HIDDEN __traits_base
     static _LIBCPP_HIDE_FROM_ABI int __width(_Tp __v)
     {
         auto __t = (64 - std::__libcpp_clz(static_cast<type>(__v | 1))) * 1233 >> 12;
-        return __t - (__v < __pow10_64[__t]) + 1;
+        return __t - (__v < __table<>::__pow10_64[__t]) + 1;
     }
 
     _LIBCPP_AVAILABILITY_TO_CHARS
@@ -160,7 +131,7 @@ struct _LIBCPP_HIDDEN __traits_base
         return __itoa::__base_10_u64(__v, __p);
     }
 
-    static _LIBCPP_HIDE_FROM_ABI decltype(__pow10_64)& __pow() { return __pow10_64; }
+    static _LIBCPP_HIDE_FROM_ABI decltype(__table<>::__pow10_64)& __pow() { return __table<>::__pow10_64; }
 };
 
 template <typename _Tp>
@@ -172,7 +143,7 @@ struct _LIBCPP_HIDDEN
     static _LIBCPP_HIDE_FROM_ABI int __width(_Tp __v)
     {
         auto __t = (32 - std::__libcpp_clz(static_cast<type>(__v | 1))) * 1233 >> 12;
-        return __t - (__v < __pow10_32[__t]) + 1;
+        return __t - (__v < __table<>::__pow10_32[__t]) + 1;
     }
 
     _LIBCPP_AVAILABILITY_TO_CHARS
@@ -181,7 +152,7 @@ struct _LIBCPP_HIDDEN
         return __itoa::__base_10_u32(__v, __p);
     }
 
-    static _LIBCPP_HIDE_FROM_ABI decltype(__pow10_32)& __pow() { return __pow10_32; }
+    static _LIBCPP_HIDE_FROM_ABI decltype(__table<>::__pow10_32)& __pow() { return __table<>::__pow10_32; }
 };
 
 template <typename _Tp>
@@ -318,55 +289,6 @@ __to_chars_integral(char* __first, char* __last, _Tp __value, int __base,
 
 namespace __itoa {
 
-static constexpr char __base_2_lut[64] = {
-  '0', '0', '0', '0',
-  '0', '0', '0', '1',
-  '0', '0', '1', '0',
-  '0', '0', '1', '1',
-  '0', '1', '0', '0',
-  '0', '1', '0', '1',
-  '0', '1', '1', '0',
-  '0', '1', '1', '1',
-  '1', '0', '0', '0',
-  '1', '0', '0', '1',
-  '1', '0', '1', '0',
-  '1', '0', '1', '1',
-  '1', '1', '0', '0',
-  '1', '1', '0', '1',
-  '1', '1', '1', '0',
-  '1', '1', '1', '1'
-};
-
-static constexpr char __base_8_lut[128] = {
-  '0', '0', '0', '1', '0', '2', '0', '3', '0', '4', '0', '5', '0', '6', '0', '7',
-  '1', '0', '1', '1', '1', '2', '1', '3', '1', '4', '1', '5', '1', '6', '1', '7',
-  '2', '0', '2', '1', '2', '2', '2', '3', '2', '4', '2', '5', '2', '6', '2', '7',
-  '3', '0', '3', '1', '3', '2', '3', '3', '3', '4', '3', '5', '3', '6', '3', '7',
-  '4', '0', '4', '1', '4', '2', '4', '3', '4', '4', '4', '5', '4', '6', '4', '7',
-  '5', '0', '5', '1', '5', '2', '5', '3', '5', '4', '5', '5', '5', '6', '5', '7',
-  '6', '0', '6', '1', '6', '2', '6', '3', '6', '4', '6', '5', '6', '6', '6', '7',
-  '7', '0', '7', '1', '7', '2', '7', '3', '7', '4', '7', '5', '7', '6', '7', '7'
-};
-
-static constexpr char __base_16_lut[512] = {
-  '0', '0', '0', '1', '0', '2', '0', '3', '0', '4', '0', '5', '0', '6', '0', '7', '0', '8', '0', '9', '0', 'a', '0', 'b', '0', 'c', '0', 'd', '0', 'e', '0', 'f',
-  '1', '0', '1', '1', '1', '2', '1', '3', '1', '4', '1', '5', '1', '6', '1', '7', '1', '8', '1', '9', '1', 'a', '1', 'b', '1', 'c', '1', 'd', '1', 'e', '1', 'f',
-  '2', '0', '2', '1', '2', '2', '2', '3', '2', '4', '2', '5', '2', '6', '2', '7', '2', '8', '2', '9', '2', 'a', '2', 'b', '2', 'c', '2', 'd', '2', 'e', '2', 'f',
-  '3', '0', '3', '1', '3', '2', '3', '3', '3', '4', '3', '5', '3', '6', '3', '7', '3', '8', '3', '9', '3', 'a', '3', 'b', '3', 'c', '3', 'd', '3', 'e', '3', 'f',
-  '4', '0', '4', '1', '4', '2', '4', '3', '4', '4', '4', '5', '4', '6', '4', '7', '4', '8', '4', '9', '4', 'a', '4', 'b', '4', 'c', '4', 'd', '4', 'e', '4', 'f',
-  '5', '0', '5', '1', '5', '2', '5', '3', '5', '4', '5', '5', '5', '6', '5', '7', '5', '8', '5', '9', '5', 'a', '5', 'b', '5', 'c', '5', 'd', '5', 'e', '5', 'f',
-  '6', '0', '6', '1', '6', '2', '6', '3', '6', '4', '6', '5', '6', '6', '6', '7', '6', '8', '6', '9', '6', 'a', '6', 'b', '6', 'c', '6', 'd', '6', 'e', '6', 'f',
-  '7', '0', '7', '1', '7', '2', '7', '3', '7', '4', '7', '5', '7', '6', '7', '7', '7', '8', '7', '9', '7', 'a', '7', 'b', '7', 'c', '7', 'd', '7', 'e', '7', 'f',
-  '8', '0', '8', '1', '8', '2', '8', '3', '8', '4', '8', '5', '8', '6', '8', '7', '8', '8', '8', '9', '8', 'a', '8', 'b', '8', 'c', '8', 'd', '8', 'e', '8', 'f',
-  '9', '0', '9', '1', '9', '2', '9', '3', '9', '4', '9', '5', '9', '6', '9', '7', '9', '8', '9', '9', '9', 'a', '9', 'b', '9', 'c', '9', 'd', '9', 'e', '9', 'f',
-  'a', '0', 'a', '1', 'a', '2', 'a', '3', 'a', '4', 'a', '5', 'a', '6', 'a', '7', 'a', '8', 'a', '9', 'a', 'a', 'a', 'b', 'a', 'c', 'a', 'd', 'a', 'e', 'a', 'f',
-  'b', '0', 'b', '1', 'b', '2', 'b', '3', 'b', '4', 'b', '5', 'b', '6', 'b', '7', 'b', '8', 'b', '9', 'b', 'a', 'b', 'b', 'b', 'c', 'b', 'd', 'b', 'e', 'b', 'f',
-  'c', '0', 'c', '1', 'c', '2', 'c', '3', 'c', '4', 'c', '5', 'c', '6', 'c', '7', 'c', '8', 'c', '9', 'c', 'a', 'c', 'b', 'c', 'c', 'c', 'd', 'c', 'e', 'c', 'f',
-  'd', '0', 'd', '1', 'd', '2', 'd', '3', 'd', '4', 'd', '5', 'd', '6', 'd', '7', 'd', '8', 'd', '9', 'd', 'a', 'd', 'b', 'd', 'c', 'd', 'd', 'd', 'e', 'd', 'f',
-  'e', '0', 'e', '1', 'e', '2', 'e', '3', 'e', '4', 'e', '5', 'e', '6', 'e', '7', 'e', '8', 'e', '9', 'e', 'a', 'e', 'b', 'e', 'c', 'e', 'd', 'e', 'e', 'e', 'f',
-  'f', '0', 'f', '1', 'f', '2', 'f', '3', 'f', '4', 'f', '5', 'f', '6', 'f', '7', 'f', '8', 'f', '9', 'f', 'a', 'f', 'b', 'f', 'c', 'f', 'd', 'f', 'e', 'f', 'f'
-};
-
 template <unsigned _Base>
 struct _LIBCPP_HIDDEN __integral;
 
@@ -394,7 +316,7 @@ struct _LIBCPP_HIDDEN __integral<2> {
       unsigned __c = __value % __divisor;
       __value /= __divisor;
       __p -= 4;
-      std::memcpy(__p, &__base_2_lut[4 * __c], 4);
+      std::memcpy(__p, &__table<>::__base_2_lut[4 * __c], 4);
     }
     do {
       unsigned __c = __value % 2;
@@ -429,7 +351,7 @@ struct _LIBCPP_HIDDEN __integral<8> {
       unsigned __c = __value % __divisor;
       __value /= __divisor;
       __p -= 2;
-      std::memcpy(__p, &__base_8_lut[2 * __c], 2);
+      std::memcpy(__p, &__table<>::__base_8_lut[2 * __c], 2);
     }
     do {
       unsigned __c = __value % 8;
@@ -465,7 +387,7 @@ struct _LIBCPP_HIDDEN __integral<16> {
       unsigned __c = __value % __divisor;
       __value /= __divisor;
       __p -= 2;
-      std::memcpy(__p, &__base_16_lut[2 * __c], 2);
+      std::memcpy(__p, &__table<>::__base_16_lut[2 * __c], 2);
     }
     if (__first != __last)
       do {

diff  --git a/libcxx/src/include/ryu/digit_table.h b/libcxx/src/include/ryu/digit_table.h
index 834a730e3cf9f..c57a0966ef2c9 100644
--- a/libcxx/src/include/ryu/digit_table.h
+++ b/libcxx/src/include/ryu/digit_table.h
@@ -50,7 +50,7 @@ _LIBCPP_BEGIN_NAMESPACE_STD
 // In order to minimize the 
diff  in the Ryu code between MSVC STL and libc++
 // the code uses the name __DIGIT_TABLE. In order to avoid code duplication it
 // reuses the table already available in libc++.
-inline constexpr auto& __DIGIT_TABLE = __itoa::__digits_base_10<>::__value;
+inline constexpr auto& __DIGIT_TABLE = __itoa::__table<>::__digits_base_10;
 
 _LIBCPP_END_NAMESPACE_STD
 


        


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