Barry Revzin 2fc9f32ca3 Make LLVM build in C++20 mode ... Part of the <=> changes in C++20 make certain patterns of writing equality operators ambiguous with themselves (sorry!). This patch goes through and adjusts all the comparison operators such that they should work in both C++17 and C++20 modes. It also makes two other small C++20-specific changes (adding a constructor to a type that cases to be an aggregate, and adding casts from u8 literals which no longer have type const char*). There were four categories of errors that this review fixes. Here are canonical examples of them, ordered from most to least common: // 1) Missing const namespace missing_const { struct A { #ifndef FIXED bool operator==(A const&); #else bool operator==(A const&) const; #endif }; bool a = A{} == A{}; // error } // 2) Type mismatch on CRTP namespace crtp_mismatch { template <typename Derived> struct Base { #ifndef FIXED bool operator==(Derived const&) const; #else // in one case changed to taking Base const& friend bool operator==(Derived const&, Derived const&); #endif }; struct D : Base<D> { }; bool b = D{} == D{}; // error } // 3) iterator/const_iterator with only mixed comparison namespace iter_const_iter { template <bool Const> struct iterator { using const_iterator = iterator<true>; iterator(); template <bool B, std::enable_if_t<(Const && !B), int> = 0> iterator(iterator<B> const&); #ifndef FIXED bool operator==(const_iterator const&) const; #else friend bool operator==(iterator const&, iterator const&); #endif }; bool c = iterator<false>{} == iterator<false>{} // error || iterator<false>{} == iterator<true>{} || iterator<true>{} == iterator<false>{} || iterator<true>{} == iterator<true>{}; } // 4) Same-type comparison but only have mixed-type operator namespace ambiguous_choice { enum Color { Red }; struct C { C(); C(Color); operator Color() const; bool operator==(Color) const; friend bool operator==(C, C); }; bool c = C{} == C{}; // error bool d = C{} == Red; } Differential revision: https://reviews.llvm.org/D78938		2020-12-17 10:44:10 +00:00
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Archive.h
ArchiveWriter.h
Binary.h
COFF.h
COFFImportFile.h
COFFModuleDefinition.h
CVDebugRecord.h
Decompressor.h
ELF.h
ELFObjectFile.h
ELFTypes.h
Error.h
IRObjectFile.h
IRSymtab.h
MachO.h
MachOUniversal.h
MachOUniversalWriter.h
Minidump.h
ModuleSymbolTable.h
ObjectFile.h
RelocationResolver.h
StackMapParser.h	Make LLVM build in C++20 mode	2020-12-17 10:44:10 +00:00
SymbolicFile.h
SymbolSize.h
TapiFile.h
TapiUniversal.h
Wasm.h
WindowsMachineFlag.h
WindowsResource.h
XCOFFObjectFile.h