From 56e6d683dba66d4f2f80145064d2bda2ea4b27b1 Mon Sep 17 00:00:00 2001 From: Stephan Bergmann Date: Wed, 7 Feb 2024 09:39:27 +0100 Subject: [PATCH] double operator < is not a strict weak ordering due to NaN ...so recent LLVM 19 trunk libc++ in debug mode complained during CppunitTest_chart2_export2 about > ~/llvm/inst/bin/../include/c++/v1/__debug_utils/strict_weak_ordering_check.h:59: assertion __comp(*(__first + __a), *(__first + __b)) failed: Your comparator is not a valid strict-weak ordering at > 5 libsystem_c.dylib 0x0000000183279a40 abort + 180 > 6 libc++.1.0.dylib 0x00000001030f9d98 _ZNSt3__123__cxx_atomic_notify_oneEPVKv + 0 > 7 libchartcorelo.dylib 0x00000002f817f0ec _ZNSt3__135__check_strict_weak_ordering_sortedB8de190000INS_11__wrap_iterIPNS_6vectorIdNS_9allocatorIdEEEEEEN5chart12_GLOBAL__N_116lcl_LessXOfPointEEEvT_SB_RT0_ + 960 > 8 libchartcorelo.dylib 0x00000002f817e6cc _ZNSt3__118__stable_sort_implB8de190000INS_17_ClassicAlgPolicyENS_11__wrap_iterIPNS_6vectorIdNS_9allocatorIdEEEEEEN5chart12_GLOBAL__N_116lcl_LessXOfPointEEEvT0_SC_RT1_ + 268 > 9 libchartcorelo.dylib 0x00000002f8172a90 _ZNSt3__111stable_sortB8de190000INS_11__wrap_iterIPNS_6vectorIdNS_9allocatorIdEEEEEEN5chart12_GLOBAL__N_116lcl_LessXOfPointEEEvT_SB_T0_ + 68 > 10 libchartcorelo.dylib 0x00000002f8172820 _ZN5chart11VDataSeries15doSortByXValuesEv + 508 > 11 libchartcorelo.dylib 0x00000002f8064c44 _ZN5chart9AreaChart12createShapesEv + 1528 > 12 libchartcorelo.dylib 0x00000002f80f2ae0 _ZN5chart9ChartView28impl_createDiagramAndContentERKNS_18CreateShapeParam2DERKN3com3sun4star3awt4SizeE + 4440 > 13 libchartcorelo.dylib 0x00000002f80f77ac _ZN5chart9ChartView14createShapes2DERKN3com3sun4star3awt4SizeE + 2728 > 14 libchartcorelo.dylib 0x00000002f80f58ec _ZN5chart9ChartView12createShapesEv + 692 > 15 libchartcorelo.dylib 0x00000002f80f4598 _ZN5chart9ChartView15impl_updateViewEb + 288 But the introduced use of `std::strong_order(first[0], second[0]) < 0` then triggered a false > lo/core/chart2/source/view/main/VDataSeries.cxx:105:61: error: NullToMemberPointer ValueDependentIsNotNull ZeroLiteral -> nullptr [loplugin:nullptr] > 105 | return std::strong_order(first[0], second[0]) < 0; > | ^ so needed some hack in loplugin:nullptr. And old versions of libc++, still used at least on Android, do not have any implementations of std::strong_order. So detect those cases in configure.ac (checking for std::strong_order for double, which is what is actually being used in the code) and fall back to operator <=> for now, even if that will not provide a strict weak ordering and will thus continue to violate the requirements of std::sort. And then our venerable clang-format 5.0.0 would have broken the token `<=>` into `<= >`, so exclude include/o3tl/compare.hxx from its mis-treatment. Change-Id: I7a64a630eb5f560dce59f3ff9d51ca3d1adc70be Reviewed-on: https://gerrit.libreoffice.org/c/core/+/163075 Tested-by: Jenkins Reviewed-by: Stephan Bergmann --- chart2/source/view/main/VDataSeries.cxx | 3 +- compilerplugins/clang/check.cxx | 10 ++++++ compilerplugins/clang/check.hxx | 2 ++ compilerplugins/clang/nullptr.cxx | 9 +++++- compilerplugins/clang/test/nullptr.cxx | 6 ++++ config_host/config_global.h.in | 3 ++ configure.ac | 23 ++++++++++++++ include/o3tl/compare.hxx | 41 +++++++++++++++++++++++++ solenv/clang-format/excludelist | 1 + 9 files changed, 96 insertions(+), 2 deletions(-) create mode 100644 include/o3tl/compare.hxx diff --git a/chart2/source/view/main/VDataSeries.cxx b/chart2/source/view/main/VDataSeries.cxx index 455c991b9f89..17dc8f1a3beb 100644 --- a/chart2/source/view/main/VDataSeries.cxx +++ b/chart2/source/view/main/VDataSeries.cxx @@ -38,6 +38,7 @@ #include #include +#include #include #include #include @@ -101,7 +102,7 @@ struct lcl_LessXOfPoint { if( !first.empty() && !second.empty() ) { - return first[0]getAs(); + if (t != nullptr) { + return TypeCheck(t->getClass()); + } + } + return TypeCheck(); +} + TerminalCheck TypeCheck::Enum() const { if (!type_.isNull()) { auto const t = type_->getAs(); diff --git a/compilerplugins/clang/check.hxx b/compilerplugins/clang/check.hxx index af6cd355a416..65ee16d77f2c 100644 --- a/compilerplugins/clang/check.hxx +++ b/compilerplugins/clang/check.hxx @@ -62,6 +62,8 @@ public: TypeCheck Pointer() const; + TypeCheck MemberPointerOf() const; + TerminalCheck Enum() const; TypeCheck LvalueReference() const; diff --git a/compilerplugins/clang/nullptr.cxx b/compilerplugins/clang/nullptr.cxx index 0213b6b05c88..04fb5bf0f9fd 100644 --- a/compilerplugins/clang/nullptr.cxx +++ b/compilerplugins/clang/nullptr.cxx @@ -131,11 +131,18 @@ bool Nullptr::VisitImplicitCastExpr(CastExpr const * expr) { case Expr::NPCK_CXX11_nullptr: break; default: - if (loplugin::TypeCheck(expr->getType()).Typedef("locale_t") + auto const tc = loplugin::TypeCheck(expr->getType()); + if (tc.Typedef("locale_t") .GlobalNamespace()) { break; // POSIX locale_t is left unspecified } + // Hack to handle libc++ and stdlibc++ `std::strong_ordering x; x < 0` etc.: + if (tc.MemberPointerOf().ClassOrStruct("_CmpUnspecifiedParam").StdNamespace() + || tc.Pointer().ClassOrStruct("__unspec").Namespace("__cmp_cat").StdNamespace()) + { + break; + } handleNull(expr->getSubExpr(), expr->getCastKindName(), k); break; } diff --git a/compilerplugins/clang/test/nullptr.cxx b/compilerplugins/clang/test/nullptr.cxx index bf7376cb6562..392a930bf9b8 100644 --- a/compilerplugins/clang/test/nullptr.cxx +++ b/compilerplugins/clang/test/nullptr.cxx @@ -7,6 +7,10 @@ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ +#include "sal/config.h" + +#include + struct S { void* p; @@ -18,6 +22,8 @@ int main() 0 // expected-error {{NullToPointer ValueDependentIsNotNull ZeroLiteral -> nullptr [loplugin:nullptr]}} }; (void)s; + + (void)(std::strong_order(0, 1) < 0); } /* vim:set shiftwidth=4 softtabstop=4 expandtab cinoptions=b1,g0,N-s cinkeys+=0=break: */ diff --git a/config_host/config_global.h.in b/config_host/config_global.h.in index dce52798a1fe..5b42b2c5a8bd 100644 --- a/config_host/config_global.h.in +++ b/config_host/config_global.h.in @@ -24,6 +24,9 @@ Any change in this header will cause a rebuild of almost everything. // constexpr", and "Adding the constinit keyword": #define HAVE_CPP_CONSTINIT_SORTED_VECTOR 0 +// Compiler supports C++20 std::strong_order: +#define HAVE_CPP_STRONG_ORDER 0 + /* "CWG motion 23: P1825R0 'Merged wording for P0527R1 and P1155R3' (DR)" in "N4829 Editors' Report -- Programming Languages -- C++" marks diff --git a/configure.ac b/configure.ac index 5937983f7ac2..721851c52d87 100644 --- a/configure.ac +++ b/configure.ac @@ -14787,6 +14787,29 @@ CXX=$save_CXX CXXFLAGS=$save_CXXFLAGS AC_LANG_POP([C++]) +AC_MSG_CHECKING([whether $CXX_BASE supports a working C++20 std::strong_order]) +dnl ...which is known to not be implemented in libc++ prior to +dnl "[libc++] +dnl [P1614] Implement [cmp.alg]'s std::{strong,weak,partial}_order" in LLVM 14: +AC_LANG_PUSH([C++]) +save_CXX=$CXX +if test "$COM" = MSC && test "$COM_IS_CLANG" != TRUE; then + CXX="env LIB=$ILIB $CXX" +fi +save_CXXFLAGS=$CXXFLAGS +CXXFLAGS="$CXXFLAGS $CXXFLAGS_CXX11" +AC_LINK_IFELSE([AC_LANG_PROGRAM([ + #include + ], [ + (void) (std::strong_order(1.0, 2.0) < 0); + ])], [ + AC_DEFINE([HAVE_CPP_STRONG_ORDER],[1]) + AC_MSG_RESULT([yes]) + ], [AC_MSG_RESULT([no])]) +CXX=$save_CXX +CXXFLAGS=$save_CXXFLAGS +AC_LANG_POP([C++]) + # =================================================================== # Creating bigger shared library to link against # =================================================================== diff --git a/include/o3tl/compare.hxx b/include/o3tl/compare.hxx new file mode 100644 index 000000000000..27c6b31ac647 --- /dev/null +++ b/include/o3tl/compare.hxx @@ -0,0 +1,41 @@ +/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4; fill-column: 100 -*- */ +/* + * This file is part of the LibreOffice project. + * + * This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, You can obtain one at http://mozilla.org/MPL/2.0/. + */ + +#pragma once + +#include + +#include + +#include + +namespace o3tl +{ +// A poor approximation of C++20 std::strong_order, falling back to operator <=> (so e.g. +// not providing a strict weak ordering for floating-point types with NaN): +#if HAVE_CPP_STRONG_ORDER + +inline constexpr auto strong_order = std::strong_order; + +#else + +namespace detail +{ +struct strong_order +{ + auto operator()(auto x, auto y) const { return x <=> y; } +}; +} + +inline constexpr auto strong_order = detail::strong_order(); + +#endif +} + +/* vim:set shiftwidth=4 softtabstop=4 expandtab cinoptions=b1,g0,N-s cinkeys+=0=break: */ diff --git a/solenv/clang-format/excludelist b/solenv/clang-format/excludelist index f15ac0ba31f3..e6e95fe011b2 100644 --- a/solenv/clang-format/excludelist +++ b/solenv/clang-format/excludelist @@ -5292,6 +5292,7 @@ include/linguistic/lngprophelp.hxx include/linguistic/misc.hxx include/linguistic/spelldta.hxx include/o3tl/any.hxx +include/o3tl/compare.hxx include/o3tl/cow_wrapper.hxx include/o3tl/enumarray.hxx include/o3tl/enumrange.hxx