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[llvm] get cl::opt instantiations working with MSVC DLL build #147810

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19 changes: 14 additions & 5 deletions llvm/include/llvm/Support/CommandLine.h
Original file line number Diff line number Diff line change
Expand Up @@ -1518,11 +1518,20 @@ class opt
[](const typename ParserClass::parser_data_type &) {};
};

extern template class opt<unsigned>;
extern template class opt<int>;
extern template class opt<std::string>;
extern template class opt<char>;
extern template class opt<bool>;
#if !defined(LLVM_ENABLE_LLVM_EXPORT_ANNOTATIONS) || \
!(defined(_MSC_VER) && !defined(__clang__))
// Only instantiate opt<std::string> when not building a Windows DLL with MSVC.
// When exporting opt<std::string>, MSVC cl implicitly exports symbols for
// std::basic_string through transitive inheritance via std::string. These
// symbols may appear in other TUs with different linkage, leading to duplicate
// symbol conflicts.
extern template class LLVM_TEMPLATE_ABI opt<std::string>;
#endif

extern template class LLVM_TEMPLATE_ABI opt<unsigned>;
extern template class LLVM_TEMPLATE_ABI opt<int>;
extern template class LLVM_TEMPLATE_ABI opt<char>;
extern template class LLVM_TEMPLATE_ABI opt<bool>;

//===----------------------------------------------------------------------===//
// Default storage class definition: external storage. This implementation
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29 changes: 24 additions & 5 deletions llvm/lib/Support/CommandLine.cpp
Original file line number Diff line number Diff line change
Expand Up @@ -68,11 +68,21 @@ template class LLVM_EXPORT_TEMPLATE basic_parser<float>;
template class LLVM_EXPORT_TEMPLATE basic_parser<std::string>;
template class LLVM_EXPORT_TEMPLATE basic_parser<char>;

template class opt<unsigned>;
template class opt<int>;
template class opt<std::string>;
template class opt<char>;
template class opt<bool>;
#if !defined(LLVM_ENABLE_LLVM_EXPORT_ANNOTATIONS) || \
!(defined(_MSC_VER) && !defined(__clang__))
// Only instantiate opt<std::string> when not building a Windows DLL with MSVC.
// When exporting opt<std::string>, MSVC cl implicitly exports symbols for
// std::basic_string through transitive inheritance via std::string. These
// symbols may appear in other TUs with different linkage, leading to duplicate
// symbol conflicts.
template class LLVM_EXPORT_TEMPLATE opt<std::string>;
#endif

template class LLVM_EXPORT_TEMPLATE opt<bool>;
template class LLVM_EXPORT_TEMPLATE opt<char>;
template class LLVM_EXPORT_TEMPLATE opt<int>;
template class LLVM_EXPORT_TEMPLATE opt<unsigned>;

} // namespace cl
} // namespace llvm

Expand All @@ -95,6 +105,15 @@ void parser<float>::anchor() {}
void parser<std::string>::anchor() {}
void parser<char>::anchor() {}

// These anchor functions instantiate opt<T> and reference its virtual
// destructor to ensure MSVC exports the corresponding vtable and typeinfo when
// building a Windows DLL. Without an explicit reference, MSVC may omit the
// instantiation at link time even if it is marked DLL-export.
void opt_bool_anchor() { opt<bool> anchor{""}; }
void opt_char_anchor() { opt<char> anchor{""}; }
void opt_int_anchor() { opt<int> anchor{""}; }
void opt_unsigned_anchor() { opt<unsigned> anchor{""}; }

//===----------------------------------------------------------------------===//

const static size_t DefaultPad = 2;
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