[libcxx-commits] [libcxx] [libc++] Refactor iostream.cpp (PR #121116)
Nikolas Klauser via libcxx-commits
libcxx-commits at lists.llvm.org
Thu Jan 2 09:34:08 PST 2025
https://github.com/philnik777 updated https://github.com/llvm/llvm-project/pull/121116
>From 762bab95bf22c1d8cd418bd9c7290ab74604224f Mon Sep 17 00:00:00 2001
From: Nikolas Klauser <nikolasklauser at berlin.de>
Date: Wed, 25 Dec 2024 23:23:34 +0100
Subject: [PATCH] [libc++] Refactor iostream.cpp
---
libcxx/src/iostream.cpp | 140 ++++++++++++++++------------------------
1 file changed, 54 insertions(+), 86 deletions(-)
diff --git a/libcxx/src/iostream.cpp b/libcxx/src/iostream.cpp
index 6db02d56037947..0d309979e216e0 100644
--- a/libcxx/src/iostream.cpp
+++ b/libcxx/src/iostream.cpp
@@ -9,7 +9,6 @@
#include "std_stream.h"
#include <__locale>
#include <new>
-#include <string>
#define _str(s) #s
#define str(s) _str(s)
@@ -17,82 +16,57 @@
_LIBCPP_BEGIN_NAMESPACE_STD
-alignas(istream) _LIBCPP_EXPORTED_FROM_ABI char cin[sizeof(istream)]
-#if defined(_LIBCPP_ABI_MICROSOFT) && defined(__clang__)
- __asm__("?cin@" _LIBCPP_ABI_NAMESPACE_STR "@std@@3V?$basic_istream at DU?$char_traits at D@" _LIBCPP_ABI_NAMESPACE_STR
- "@std@@@12 at A")
-#endif
- ;
-alignas(__stdinbuf<char>) static char __cin[sizeof(__stdinbuf<char>)];
static mbstate_t mb_cin;
+static mbstate_t mb_cout;
+static mbstate_t mb_cerr;
#if _LIBCPP_HAS_WIDE_CHARACTERS
-alignas(wistream) _LIBCPP_EXPORTED_FROM_ABI char wcin[sizeof(wistream)]
-# if defined(_LIBCPP_ABI_MICROSOFT) && defined(__clang__)
- __asm__("?wcin@" _LIBCPP_ABI_NAMESPACE_STR "@std@@3V?$basic_istream at _WU?$char_traits at _W@" _LIBCPP_ABI_NAMESPACE_STR
- "@std@@@12 at A")
-# endif
- ;
-alignas(__stdinbuf<wchar_t>) static char __wcin[sizeof(__stdinbuf<wchar_t>)];
static mbstate_t mb_wcin;
-#endif // _LIBCPP_HAS_WIDE_CHARACTERS
-
-alignas(ostream) _LIBCPP_EXPORTED_FROM_ABI char cout[sizeof(ostream)]
-#if defined(_LIBCPP_ABI_MICROSOFT) && defined(__clang__)
- __asm__("?cout@" _LIBCPP_ABI_NAMESPACE_STR "@std@@3V?$basic_ostream at DU?$char_traits at D@" _LIBCPP_ABI_NAMESPACE_STR
- "@std@@@12 at A")
+static mbstate_t mb_wcout;
+static mbstate_t mb_wcerr;
#endif
- ;
-alignas(__stdoutbuf<char>) static char __cout[sizeof(__stdoutbuf<char>)];
-static mbstate_t mb_cout;
-#if _LIBCPP_HAS_WIDE_CHARACTERS
-alignas(wostream) _LIBCPP_EXPORTED_FROM_ABI char wcout[sizeof(wostream)]
-# if defined(_LIBCPP_ABI_MICROSOFT) && defined(__clang__)
- __asm__("?wcout@" _LIBCPP_ABI_NAMESPACE_STR "@std@@3V?$basic_ostream at _WU?$char_traits at _W@" _LIBCPP_ABI_NAMESPACE_STR
- "@std@@@12 at A")
-# endif
- ;
-alignas(__stdoutbuf<wchar_t>) static char __wcout[sizeof(__stdoutbuf<wchar_t>)];
-static mbstate_t mb_wcout;
-#endif // _LIBCPP_HAS_WIDE_CHARACTERS
+#if __has_cpp_attribute(clang::no_destroy)
+template <class T>
+using no_destroy_t = T;
-alignas(ostream) _LIBCPP_EXPORTED_FROM_ABI char cerr[sizeof(ostream)]
-#if defined(_LIBCPP_ABI_MICROSOFT) && defined(__clang__)
- __asm__("?cerr@" _LIBCPP_ABI_NAMESPACE_STR "@std@@3V?$basic_ostream at DU?$char_traits at D@" _LIBCPP_ABI_NAMESPACE_STR
- "@std@@@12 at A")
+# define STREAM_ATTRS [[clang::no_destroy]] _LIBCPP_INIT_PRIORITY_MAX
+#else
+template <class T>
+using no_destroy_t = __no_destroy<T>;
+
+# define STREAM_ATTRS _LIBCPP_INIT_PRIORITY_MAX
#endif
- ;
-alignas(__stdoutbuf<char>) static char __cerr[sizeof(__stdoutbuf<char>)];
-static mbstate_t mb_cerr;
-#if _LIBCPP_HAS_WIDE_CHARACTERS
-alignas(wostream) _LIBCPP_EXPORTED_FROM_ABI char wcerr[sizeof(wostream)]
-# if defined(_LIBCPP_ABI_MICROSOFT) && defined(__clang__)
- __asm__("?wcerr@" _LIBCPP_ABI_NAMESPACE_STR "@std@@3V?$basic_ostream at _WU?$char_traits at _W@" _LIBCPP_ABI_NAMESPACE_STR
- "@std@@@12 at A")
-# endif
- ;
-alignas(__stdoutbuf<wchar_t>) static char __wcerr[sizeof(__stdoutbuf<wchar_t>)];
-static mbstate_t mb_wcerr;
-#endif // _LIBCPP_HAS_WIDE_CHARACTERS
+# 41 __FILE__ 3 // FIXME: Remove this (and the one below) once https://llvm.org/PR121108 is fixed.
-alignas(ostream) _LIBCPP_EXPORTED_FROM_ABI char clog[sizeof(ostream)]
-#if defined(_LIBCPP_ABI_MICROSOFT) && defined(__clang__)
- __asm__("?clog@" _LIBCPP_ABI_NAMESPACE_STR "@std@@3V?$basic_ostream at DU?$char_traits at D@" _LIBCPP_ABI_NAMESPACE_STR
- "@std@@@12 at A")
-#endif
- ;
+STREAM_ATTRS static no_destroy_t<__stdinbuf<char>> cin_stdbuf(stdin, &mb_cin);
+STREAM_ATTRS _LIBCPP_EXPORTED_FROM_ABI no_destroy_t<istream> cin(&cin_stdbuf);
+
+STREAM_ATTRS static no_destroy_t<__stdoutbuf<char>> cout_stdbuf(stdout, &mb_cout);
+STREAM_ATTRS _LIBCPP_EXPORTED_FROM_ABI no_destroy_t<ostream> cout(&cout_stdbuf);
+
+STREAM_ATTRS static no_destroy_t<__stdoutbuf<char>> cerr_stdbuf(stderr, &mb_cerr);
+STREAM_ATTRS _LIBCPP_EXPORTED_FROM_ABI no_destroy_t<ostream> cerr(&cerr_stdbuf);
+
+STREAM_ATTRS _LIBCPP_EXPORTED_FROM_ABI no_destroy_t<ostream> clog(&cerr_stdbuf);
#if _LIBCPP_HAS_WIDE_CHARACTERS
-alignas(wostream) _LIBCPP_EXPORTED_FROM_ABI char wclog[sizeof(wostream)]
-# if defined(_LIBCPP_ABI_MICROSOFT) && defined(__clang__)
- __asm__("?wclog@" _LIBCPP_ABI_NAMESPACE_STR "@std@@3V?$basic_ostream at _WU?$char_traits at _W@" _LIBCPP_ABI_NAMESPACE_STR
- "@std@@@12 at A")
-# endif
- ;
+STREAM_ATTRS static __stdinbuf<wchar_t> wcin_stdbuf(stdin, &mb_wcin);
+STREAM_ATTRS _LIBCPP_EXPORTED_FROM_ABI wistream wcin(&wcin_stdbuf);
+
+STREAM_ATTRS static no_destroy_t<__stdoutbuf<wchar_t>> wcout_stdbuf(stdout, &mb_wcout);
+STREAM_ATTRS _LIBCPP_EXPORTED_FROM_ABI no_destroy_t<wostream> wcout(&wcout_stdbuf);
+
+STREAM_ATTRS static no_destroy_t<__stdoutbuf<wchar_t>> wcerr_stdbuf(stderr, &mb_wcerr);
+STREAM_ATTRS _LIBCPP_EXPORTED_FROM_ABI no_destroy_t<wostream> wcerr(&wcerr_stdbuf);
+
+STREAM_ATTRS _LIBCPP_EXPORTED_FROM_ABI no_destroy_t<wostream> wclog(&wcerr_stdbuf);
+
#endif // _LIBCPP_HAS_WIDE_CHARACTERS
+# 68 __FILE__ 1
+
// Pretend we're inside a system header so the compiler doesn't flag the use of the init_priority
// attribute with a value that's reserved for the implementation (we're the implementation).
#include "iostream_init.h"
@@ -121,40 +95,34 @@ class DoIOSInit {
~DoIOSInit();
};
+auto&& unwrap(auto& val) { return val; }
+
+template <class T>
+auto&& unwrap(__no_destroy<T>& val) {
+ return val.__get();
+}
+
DoIOSInit::DoIOSInit() {
force_locale_initialization();
- istream* cin_ptr = ::new (cin) istream(::new (__cin) __stdinbuf<char>(stdin, &mb_cin));
- ostream* cout_ptr = ::new (cout) ostream(::new (__cout) __stdoutbuf<char>(stdout, &mb_cout));
- ostream* cerr_ptr = ::new (cerr) ostream(::new (__cerr) __stdoutbuf<char>(stderr, &mb_cerr));
- ::new (clog) ostream(cerr_ptr->rdbuf());
- cin_ptr->tie(cout_ptr);
- std::unitbuf(*cerr_ptr);
- cerr_ptr->tie(cout_ptr);
+ unwrap(cin).tie(&unwrap(cout));
+ std::unitbuf(unwrap(cerr));
+ unwrap(cerr).tie(&unwrap(cout));
#if _LIBCPP_HAS_WIDE_CHARACTERS
- wistream* wcin_ptr = ::new (wcin) wistream(::new (__wcin) __stdinbuf<wchar_t>(stdin, &mb_wcin));
- wostream* wcout_ptr = ::new (wcout) wostream(::new (__wcout) __stdoutbuf<wchar_t>(stdout, &mb_wcout));
- wostream* wcerr_ptr = ::new (wcerr) wostream(::new (__wcerr) __stdoutbuf<wchar_t>(stderr, &mb_wcerr));
- ::new (wclog) wostream(wcerr_ptr->rdbuf());
-
- wcin_ptr->tie(wcout_ptr);
- std::unitbuf(*wcerr_ptr);
- wcerr_ptr->tie(wcout_ptr);
+ unwrap(wcin).tie(&unwrap(wcout));
+ std::unitbuf(unwrap(wcerr));
+ unwrap(wcerr).tie(&unwrap(wcout));
#endif
}
DoIOSInit::~DoIOSInit() {
- ostream* cout_ptr = reinterpret_cast<ostream*>(cout);
- cout_ptr->flush();
- ostream* clog_ptr = reinterpret_cast<ostream*>(clog);
- clog_ptr->flush();
+ unwrap(cout).flush();
+ unwrap(clog).flush();
#if _LIBCPP_HAS_WIDE_CHARACTERS
- wostream* wcout_ptr = reinterpret_cast<wostream*>(wcout);
- wcout_ptr->flush();
- wostream* wclog_ptr = reinterpret_cast<wostream*>(wclog);
- wclog_ptr->flush();
+ unwrap(wcout).flush();
+ unwrap(wclog).flush();
#endif
}
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