Move charconv tables

stl/CMakeLists.txt

@@ -220,6 +220,7 @@ set(HEADERS
     ${CMAKE_CURRENT_LIST_DIR}/inc/xcharconv.h
     ${CMAKE_CURRENT_LIST_DIR}/inc/xcharconv_ryu.h
     ${CMAKE_CURRENT_LIST_DIR}/inc/xcharconv_ryu_tables.h
+    ${CMAKE_CURRENT_LIST_DIR}/inc/xcharconv_tables.h
     ${CMAKE_CURRENT_LIST_DIR}/inc/xerrc.h
     ${CMAKE_CURRENT_LIST_DIR}/inc/xfacet
     ${CMAKE_CURRENT_LIST_DIR}/inc/xfilesystem_abi.h
@@ -263,6 +264,7 @@ set(ALIAS_SOURCES_X86_X64
 # Objs that exist in both libcpmt[d][01].lib and msvcprt[d].lib.
 set(IMPLIB_SOURCES
     ${CMAKE_CURRENT_LIST_DIR}/src/asan_noop.cpp
+    ${CMAKE_CURRENT_LIST_DIR}/src/charconv.cpp
     ${CMAKE_CURRENT_LIST_DIR}/src/filesystem.cpp
     ${CMAKE_CURRENT_LIST_DIR}/src/format.cpp
     ${CMAKE_CURRENT_LIST_DIR}/src/locale0_implib.cpp
@@ -271,6 +273,9 @@ set(IMPLIB_SOURCES
     ${CMAKE_CURRENT_LIST_DIR}/src/stacktrace.cpp
     ${CMAKE_CURRENT_LIST_DIR}/src/syserror_import_lib.cpp
     ${CMAKE_CURRENT_LIST_DIR}/src/vector_algorithms.cpp
+    ${CMAKE_CURRENT_LIST_DIR}/src/xcharconv_ryu_tables.cpp
+    ${CMAKE_CURRENT_LIST_DIR}/src/xcharconv_tables_double.cpp
+    ${CMAKE_CURRENT_LIST_DIR}/src/xcharconv_tables_float.cpp
     ${CMAKE_CURRENT_LIST_DIR}/src/xonce2.cpp
 )
 

stl/inc/header-units.json

@@ -130,6 +130,7 @@
         "xcharconv.h",
         "xcharconv_ryu.h",
         "xcharconv_ryu_tables.h",
+        "xcharconv_tables.h",
         "xerrc.h",
         "xfacet",
         "xfilesystem_abi.h",

stl/inc/xcharconv_tables.h

@@ -0,0 +1,120 @@
+// xcharconv_tables.h internal header
+
+// Copyright (c) Microsoft Corporation.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
+#pragma once
+#ifndef _XCHARCONV_TABLES_H
+#define _XCHARCONV_TABLES_H
+#include <yvals_core.h>
+#if _STL_COMPILER_PREPROCESSOR
+
+#if !_HAS_CXX17
+#error The contents of <charconv> are only available with C++17. (Also, you should not include this internal header.)
+#endif // !_HAS_CXX17
+
+#include <cstdint>
+
+#pragma pack(push, _CRT_PACKING)
+#pragma warning(push, _STL_WARNING_LEVEL)
+#pragma warning(disable : _STL_DISABLED_WARNINGS)
+_STL_DISABLE_CLANG_WARNINGS
+#pragma push_macro("new")
+#undef new
+
+// For general precision, we can use lookup tables to avoid performing trial formatting.
+
+// For a simple example, imagine counting the number of digits D in an integer, and needing to know
+// whether D is less than 3, equal to 3/4/5/6, or greater than 6. We could use a lookup table:
+// D | Largest integer with D digits
+// 2 |      99
+// 3 |     999
+// 4 |   9'999
+// 5 |  99'999
+// 6 | 999'999
+// 7 | table end
+// Looking up an integer in this table with lower_bound() will work:
+// * Too-small integers, like 7, 70, and 99, will cause lower_bound() to return the D == 2 row. (If all we care
+//   about is whether D is less than 3, then it's okay to smash the D == 1 and D == 2 cases together.)
+// * Integers in [100, 999] will cause lower_bound() to return the D == 3 row, and so forth.
+// * Too-large integers, like 1'000'000 and above, will cause lower_bound() to return the end of the table. If we
+//   compute D from that index, this will be considered D == 7, which will activate any "greater than 6" logic.
+
+// Floating-point is slightly more complicated.
+
+// The ordinary lookup tables are for X within [-5, 38] for float, and [-5, 308] for double.
+// (-5 absorbs too-negative exponents, outside the P > X >= -4 criterion. 38 and 308 are the maximum exponents.)
+// Due to the P > X condition, we can use a subset of the table for X within [-5, P - 1], suitably clamped.
+
+// When P is small, rounding can affect X. For example:
+// For P == 1, the largest double with X == 0 is: 9.4999999999999982236431605997495353221893310546875
+// For P == 2, the largest double with X == 0 is: 9.949999999999999289457264239899814128875732421875
+// For P == 3, the largest double with X == 0 is: 9.9949999999999992184029906638897955417633056640625
+
+// Exponent adjustment is a concern for P within [1, 7] for float, and [1, 15] for double (determined via
+// brute force). While larger values of P still perform rounding, they can't trigger exponent adjustment.
+// This is because only values with repeated '9' digits can undergo exponent adjustment during rounding,
+// and floating-point granularity limits the number of consecutive '9' digits that can appear.
+
+// So, we need special lookup tables for small values of P.
+// These tables have varying lengths due to the P > X >= -4 criterion. For example:
+// For P == 1, need table entries for X: -5, -4, -3, -2, -1, 0
+// For P == 2, need table entries for X: -5, -4, -3, -2, -1, 0, 1
+// For P == 3, need table entries for X: -5, -4, -3, -2, -1, 0, 1, 2
+// For P == 4, need table entries for X: -5, -4, -3, -2, -1, 0, 1, 2, 3
+
+// We can concatenate these tables for compact storage, using triangular numbers to access them.
+// The table for P begins at index (P - 1) * (P + 10) / 2 with length P + 5.
+
+// For both the ordinary and special lookup tables, after an index I is returned by lower_bound(), X is I - 5.
+
+// We need to special-case the floating-point value 0.0, which is considered to have X == 0.
+// Otherwise, the lookup tables would consider it to have a highly negative X.
+
+// Finally, because we're working with positive floating-point values,
+// representation comparisons behave identically to floating-point comparisons.
+
+// The generator is in /tools/scripts/charconv_tables_generate.cpp
+
+_STD_BEGIN
+
+template <class _Floating>
+struct _General_precision_tables_2;
+
+template <>
+struct _General_precision_tables_2<float> {
+    static const int _Max_special_P;
+
+    static const uint32_t _Special_X_table[63];
+
+    static const int _Max_P;
+
+    static const uint32_t _Ordinary_X_table[44];
+};
+
+inline constexpr int _General_precision_tables_2<float>::_Max_special_P = 7; // TRANSITION, VSO-1579484
+inline constexpr int _General_precision_tables_2<float>::_Max_P         = 39; // TRANSITION, VSO-1579484
+
+template <>
+struct _General_precision_tables_2<double> {
+    static const int _Max_special_P;
+
+    static const uint64_t _Special_X_table[195];
+
+    static const int _Max_P;
+
+    static const uint64_t _Ordinary_X_table[314];
+};
+
+inline constexpr int _General_precision_tables_2<double>::_Max_special_P = 15; // TRANSITION, VSO-1579484
+inline constexpr int _General_precision_tables_2<double>::_Max_P         = 309; // TRANSITION, VSO-1579484
+
+_STD_END
+
+#pragma pop_macro("new")
+_STL_RESTORE_CLANG_WARNINGS
+#pragma warning(pop)
+#pragma pack(pop)
+
+#endif // _STL_COMPILER_PREPROCESSOR
+#endif // _XCHARCONV_TABLES_H

stl/msbuild/stl_base/stl.files.settings.targets

@@ -161,6 +161,7 @@ SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
              (controlled by IncludeInLink and IncludeInImportLib). -->
         <BuildFiles Include="
             $(CrtRoot)\github\stl\src\asan_noop.cpp;
+            $(CrtRoot)\github\stl\src\charconv.cpp;
             $(CrtRoot)\github\stl\src\filesystem.cpp;
             $(CrtRoot)\github\stl\src\format.cpp;
             $(CrtRoot)\github\stl\src\locale0_implib.cpp;
@@ -169,6 +170,9 @@ SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
             $(CrtRoot)\github\stl\src\stacktrace.cpp;
             $(CrtRoot)\github\stl\src\syserror_import_lib.cpp;
             $(CrtRoot)\github\stl\src\vector_algorithms.cpp;
+            $(CrtRoot)\github\stl\src\xcharconv_ryu_tables.cpp;
+            $(CrtRoot)\github\stl\src\xcharconv_tables_double.cpp;
+            $(CrtRoot)\github\stl\src\xcharconv_tables_float.cpp;
             $(CrtRoot)\github\stl\src\xonce2.cpp;
             ">
             <BuildAs>nativecpp</BuildAs>

stl/src/charconv.cpp

@@ -0,0 +1,81 @@
+// Copyright (c) Microsoft Corporation.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
+// This must be as small as possible, because its contents are
+// injected into the msvcprt.lib and msvcprtd.lib import libraries.
+// Do not include or define anything else here.
+// In particular, basic_string must not be included here.
+
+#include <cstdint>
+
+// Generated by /tools/scripts/charconv_generate.cpp
+
+namespace std {
+
+    extern const uint32_t _Large_power_data[578] = {0x540be400, 0x00000002, 0x63100000, 0x6bc75e2d, 0x00000005,
+        0x40000000, 0x4674edea, 0x9f2c9cd0, 0x0000000c, 0xb9f56100, 0x5ca4bfab, 0x6329f1c3, 0x0000001d, 0xb5640000,
+        0xc40534fd, 0x926687d2, 0x6c3b15f9, 0x00000044, 0x10000000, 0x946590d9, 0xd762422c, 0x9a224501, 0x4f272617,
+        0x0000009f, 0x07950240, 0x245689c1, 0xc5faa71c, 0x73c86d67, 0xebad6ddc, 0x00000172, 0xcec10000, 0x63a22764,
+        0xefa418ca, 0xcdd17b25, 0x6bdfef70, 0x9dea3e1f, 0x0000035f, 0xe4000000, 0xcdc3fe6e, 0x66bc0c6a, 0x2e391f32,
+        0x5a450203, 0x71d2f825, 0xc3c24a56, 0x000007da, 0xa82e8f10, 0xaab24308, 0x8e211a7c, 0xf38ace40, 0x84c4ce0b,
+        0x7ceb0b27, 0xad2594c3, 0x00001249, 0xdd1a4000, 0xcc9f54da, 0xdc5961bf, 0xc75cabab, 0xf505440c, 0xd1bc1667,
+        0xfbb7af52, 0x608f8d29, 0x00002a94, 0x21000000, 0x17bb8a0c, 0x56af8ea4, 0x06479fa9, 0x5d4bb236, 0x80dc5fe0,
+        0xf0feaa0a, 0xa88ed940, 0x6b1a80d0, 0x00006323, 0x324c3864, 0x8357c796, 0xe44a42d5, 0xd9a92261, 0xbd3c103d,
+        0x91e5f372, 0xc0591574, 0xec1da60d, 0x102ad96c, 0x0000e6d3, 0x1e851000, 0x6e4f615b, 0x187b2a69, 0x0450e21c,
+        0x2fdd342b, 0x635027ee, 0xa6c97199, 0x8e4ae916, 0x17082e28, 0x1a496e6f, 0x0002196e, 0x32400000, 0x04ad4026,
+        0xf91e7250, 0x2994d1d5, 0x665bcdbb, 0xa23b2e96, 0x65fa7ddb, 0x77de53ac, 0xb020a29b, 0xc6bff953, 0x4b9425ab,
+        0x0004e34d, 0xfbc32d81, 0x5222d0f4, 0xb70f2850, 0x5713f2f3, 0xdc421413, 0xd6395d7d, 0xf8591999, 0x0092381c,
+        0x86b314d6, 0x7aa577b9, 0x12b7fe61, 0x000b616a, 0x1d11e400, 0x56c3678d, 0x3a941f20, 0x9b09368b, 0xbd706908,
+        0x207665be, 0x9b26c4eb, 0x1567e89d, 0x9d15096e, 0x7132f22b, 0xbe485113, 0x45e5a2ce, 0x001a7f52, 0xbb100000,
+        0x02f79478, 0x8c1b74c0, 0xb0f05d00, 0xa9dbc675, 0xe2d9b914, 0x650f72df, 0x77284b4c, 0x6df6e016, 0x514391c2,
+        0x2795c9cf, 0xd6e2ab55, 0x9ca8e627, 0x003db1a6, 0x40000000, 0xf4ecd04a, 0x7f2388f0, 0x580a6dc5, 0x43bf046f,
+        0xf82d5dc3, 0xee110848, 0xfaa0591c, 0xcdf4f028, 0x192ea53f, 0xbcd671a0, 0x7d694487, 0x10f96e01, 0x791a569d,
+        0x008fa475, 0xb9b2e100, 0x8288753c, 0xcd3f1693, 0x89b43a6b, 0x089e87de, 0x684d4546, 0xfddba60c, 0xdf249391,
+        0x3068ec13, 0x99b44427, 0xb68141ee, 0x5802cac3, 0xd96851f1, 0x7d7625a2, 0x014e718d, 0xfb640000, 0xf25a83e6,
+        0x9457ad0f, 0x0080b511, 0x2029b566, 0xd7c5d2cf, 0xa53f6d7d, 0xcdb74d1c, 0xda9d70de, 0xb716413d, 0x71d0ca4e,
+        0xd7e41398, 0x4f403a90, 0xf9ab3fe2, 0x264d776f, 0x030aafe6, 0x10000000, 0x09ab5531, 0xa60c58d2, 0x566126cb,
+        0x6a1c8387, 0x7587f4c1, 0x2c44e876, 0x41a047cf, 0xc908059e, 0xa0ba063e, 0xe7cfc8e8, 0xe1fac055, 0xef0144b2,
+        0x24207eb0, 0xd1722573, 0xe4b8f981, 0x071505ae, 0x7a3b6240, 0xcea45d4f, 0x4fe24133, 0x210f6d6d, 0xe55633f2,
+        0x25c11356, 0x28ebd797, 0xd396eb84, 0x1e493b77, 0x471f2dae, 0x96ad3820, 0x8afaced1, 0x4edecddb, 0x5568c086,
+        0xb2695da1, 0x24123c89, 0x107d4571, 0x1c410000, 0x6e174a27, 0xec62ae57, 0xef2289aa, 0xb6a2fbdd, 0x17e1efe4,
+        0x3366bdf2, 0x37b48880, 0xbfb82c3e, 0x19acde91, 0xd4f46408, 0x35ff6a4e, 0x67566a0e, 0x40dbb914, 0x782a3bca,
+        0x6b329b68, 0xf5afc5d9, 0x266469bc, 0xe4000000, 0xfb805ff4, 0xed55d1af, 0x9b4a20a8, 0xab9757f8, 0x01aefe0a,
+        0x4a2ca67b, 0x1ebf9569, 0xc7c41c29, 0xd8d5d2aa, 0xd136c776, 0x93da550c, 0x9ac79d90, 0x254bcba8, 0x0df07618,
+        0xf7a88809, 0x3a1f1074, 0xe54811fc, 0x59638ead, 0x97cbe710, 0x26d769e8, 0xb4e4723e, 0x5b90aa86, 0x9c333922,
+        0x4b7a0775, 0x2d47e991, 0x9a6ef977, 0x160b40e7, 0x0c92f8c4, 0xf25ff010, 0x25c36c11, 0xc9f98b42, 0x730b919d,
+        0x05ff7caf, 0xb0432d85, 0x2d2b7569, 0xa657842c, 0xd01fef10, 0xc77a4000, 0xe8b862e5, 0x10d8886a, 0xc8cd98e5,
+        0x108955c5, 0xd059b655, 0x58fbbed4, 0x03b88231, 0x034c4519, 0x194dc939, 0x1fc500ac, 0x794cc0e2, 0x3bc980a1,
+        0xe9b12dd1, 0x5e6d22f8, 0x7b38899a, 0xce7919d8, 0x78c67672, 0x79e5b99f, 0xe494034e, 0x00000001, 0xa1000000,
+        0x6c5cd4e9, 0x9be47d6f, 0xf93bd9e7, 0x77626fa1, 0xc68b3451, 0xde2b59e8, 0xcf3cde58, 0x2246ff58, 0xa8577c15,
+        0x26e77559, 0x17776753, 0xebe6b763, 0xe3fd0a5f, 0x33e83969, 0xa805a035, 0xf631b987, 0x211f0f43, 0xd85a43db,
+        0xab1bf596, 0x683f19a2, 0x00000004, 0xbe7dfe64, 0x4bc9042f, 0xe1f5edb0, 0x8fa14eda, 0xe409db73, 0x674fee9c,
+        0xa9159f0d, 0xf6b5b5d6, 0x7338960e, 0xeb49c291, 0x5f2b97cc, 0x0f383f95, 0x2091b3f6, 0xd1783714, 0xc1d142df,
+        0x153e22de, 0x8aafdf57, 0x77f5e55f, 0xa3e7ca8b, 0x032f525b, 0x42e74f3d, 0x0000000a, 0xf4dd1000, 0x5d450952,
+        0xaeb442e1, 0xa3b3342e, 0x3fcda36f, 0xb4287a6e, 0x4bc177f7, 0x67d2c8d0, 0xaea8f8e0, 0xadc93b67, 0x6cc856b3,
+        0x959d9d0b, 0x5b48c100, 0x4abe8a3d, 0x52d936f4, 0x71dbe84d, 0xf91c21c5, 0x4a458109, 0xd7aad86a, 0x08e14c7c,
+        0x759ba59c, 0xe43c8800, 0x00000017, 0x92400000, 0x04f110d4, 0x186472be, 0x8736c10c, 0x1478abfb, 0xfc51af29,
+        0x25eb9739, 0x4c2b3015, 0xa1030e0b, 0x28fe3c3b, 0x7788fcba, 0xb89e4358, 0x733de4a4, 0x7c46f2c2, 0x8f746298,
+        0xdb19210f, 0x2ea3b6ae, 0xaa5014b2, 0xea39ab8d, 0x97963442, 0x01dfdfa9, 0xd2f3d3fe, 0xa0790280, 0x00000037,
+        0x509c9b01, 0xc7dcadf1, 0x383dad2c, 0x73c64d37, 0xea6d67d0, 0x519ba806, 0xc403f2f8, 0xa052e1a2, 0xd710233a,
+        0x448573a9, 0xcf12d9ba, 0x70871803, 0x52dc3a9b, 0xe5b252e8, 0x0717fb4e, 0xbe4da62f, 0x0aabd7e1, 0x8c62ed4f,
+        0xceb9ec7b, 0xd4664021, 0xa1158300, 0xcce375e6, 0x842f29f2, 0x00000081, 0x7717e400, 0xd3f5fb64, 0xa0763d71,
+        0x7d142fe9, 0x33f44c66, 0xf3b8f12e, 0x130f0d8e, 0x734c9469, 0x60260fa8, 0x3c011340, 0xcc71880a, 0x37a52d21,
+        0x8adac9ef, 0x42bb31b4, 0xd6f94c41, 0xc88b056c, 0xe20501b8, 0x5297ed7c, 0x62c361c4, 0x87dad8aa, 0xb833eade,
+        0x94f06861, 0x13cc9abd, 0x8dc1d56a, 0x0000012d, 0x13100000, 0xc67a36e8, 0xf416299e, 0xf3493f0a, 0x77a5a6cf,
+        0xa4be23a3, 0xcca25b82, 0x3510722f, 0xbe9d447f, 0xa8c213b8, 0xc94c324e, 0xbc9e33ad, 0x76acfeba, 0x2e4c2132,
+        0x3e13cd32, 0x70fe91b4, 0xbb5cd936, 0x42149785, 0x46cc1afd, 0xe638ddf8, 0x690787d2, 0x1a02d117, 0x3eb5f1fe,
+        0xc3b9abae, 0x1c08ee6f, 0x000002be, 0x40000000, 0x8140c2aa, 0x2cf877d9, 0x71e1d73d, 0xd5e72f98, 0x72516309,
+        0xafa819dd, 0xd62a5a46, 0x2a02dcce, 0xce46ddfe, 0x2713248d, 0xb723d2ad, 0xc404bb19, 0xb706cc2b, 0x47b1ebca,
+        0x9d094bdc, 0xc5dc02ca, 0x31e6518e, 0x8ec35680, 0x342f58a8, 0x8b041e42, 0xfebfe514, 0x05fffc13, 0x6763790f,
+        0x66d536fd, 0xb9e15076, 0x00000662, 0x67b06100, 0xd2010a1a, 0xd005e1c0, 0xdb12733b, 0xa39f2e3f, 0x61b29de2,
+        0x2a63dce2, 0x942604bc, 0x6170d59b, 0xc2e32596, 0x140b75b9, 0x1f1d2c21, 0xb8136a60, 0x89d23ba2, 0x60f17d73,
+        0xc6cad7df, 0x0669df2b, 0x24b88737, 0x669306ed, 0x19496eeb, 0x938ddb6f, 0x5e748275, 0xc56e9a36, 0x3690b731,
+        0xc82842c5, 0x24ae798e, 0x00000ede, 0x41640000, 0xd5889ac1, 0xd9432c99, 0xa280e71a, 0x6bf63d2e, 0x8249793d,
+        0x79e7a943, 0x22fde64a, 0xe0d6709a, 0x05cacfef, 0xbd8da4d7, 0xe364006c, 0xa54edcb3, 0xa1a8086e, 0x748f459e,
+        0xfc8e54c8, 0xcc74c657, 0x42b8c3d4, 0x57d9636e, 0x35b55bcc, 0x6c13fee9, 0x1ac45161, 0xb595badb, 0xa1f14e9d,
+        0xdcf9e750, 0x07637f71, 0xde2f9f2b, 0x0000229d, 0x10000000, 0x3c5ebd89, 0xe3773756, 0x3dcba338, 0x81d29e4f,
+        0xa4f79e2c, 0xc3f9c774, 0x6a1ce797, 0xac5fe438, 0x07f38b9c, 0xd588ecfa, 0x3e5ac1ac, 0x85afccce, 0x9d1f3f70,
+        0xe82d6dd3, 0x177d180c, 0x5e69946f, 0x648e2ce1, 0x95a13948, 0x340fe011, 0xb4173c58, 0x2748f694, 0x7c2657bd,
+        0x758bda2e, 0x3b8090a0, 0x2ddbb613, 0x6dcf4890, 0x24e4047e, 0x00005099};
+
+} // namespace std