libcxx/test/std/strings/basic.string/string.capacity/shrink_to_fit.explicit_instantiation.sh.cpp

   1 //===----------------------------------------------------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 // This test checks that we can explicitly instantiate std::string with a custom
  10 // character type and traits and then use `shrink_to_fit`. In particular, this is
  11 // a regression test for the bug that was reported at https://stackoverflow.com/q/69520633/627587
  12 // and https://seedcentral.apple.com/sm/feedback_collector/radar/85053279.
  13
  14 // RUN: %{cxx} %{flags} %{compile_flags} %s %{link_flags} -DTU1 -c -o %t.tu1.o
  15 // RUN: %{cxx} %{flags} %{compile_flags} %s %{link_flags} -DTU2 -c -o %t.tu2.o
  16 // RUN: %{cxx} %{flags} %t.tu1.o %t.tu2.o %{link_flags} -o %t.exe
  17
  18 // UNSUPPORTED: no-localization
  19
  20 #include <cstdint>
  21 #include <ios>
  22 #include <string>
  23
  24 typedef std::uint16_t char16;
  25
  26 struct string16_char_traits {
  27   typedef char16 char_type;
  28   typedef int int_type;
  29
  30   typedef std::streamoff off_type;
  31   typedef std::mbstate_t state_type;
  32   typedef std::fpos<state_type> pos_type;
  33
  34   static void assign(char_type&, const char_type&) {}
  35   static bool eq(const char_type&, const char_type&) { return false; }
  36   static bool lt(const char_type&, const char_type&) { return false; }
  37   static int compare(const char_type*, const char_type*, std::size_t) { return 0; }
  38   static std::size_t length(const char_type*) { return 0; }
  39   static const char_type* find(const char_type*, std::size_t, const char_type&) { return nullptr; }
  40   static char_type* move(char_type*, const char_type*, std::size_t) { return nullptr; }
  41   static char_type* copy(char_type*, const char_type*, std::size_t) { return nullptr; }
  42   static char_type* assign(char_type*, std::size_t, char_type) { return nullptr; }
  43   static int_type not_eof(const int_type&) { return 0; }
  44   static char_type to_char_type(const int_type&) { return char_type(); }
  45   static int_type to_int_type(const char_type&) { return int_type(); }
  46   static bool eq_int_type(const int_type&, const int_type&) { return false; }
  47   static int_type eof() { return int_type(); }
  48 };
  49
  50 #if defined(TU1)
  51 template class std::basic_string<char16, string16_char_traits>;
  52 #else
  53 extern template class std::basic_string<char16, string16_char_traits>;
  54
  55 int main(int, char**) {
  56   std::basic_string<char16, string16_char_traits> s;
  57   s.shrink_to_fit();
  58 }
  59 #endif