maxjhandsome
/
llvm-project
forked from OSchip/llvm-project
1
0
Fork 0
Code Issues Pull Requests Packages Releases Wiki Activity

[libc++] Explicitly enumerate std::string external instantiations - Attempt 2 

The GCC build failures have been addressed, and the LLDB failures were
  fixed by LLDB.

   I have also verified that the apple-clang 9.0 segfault no longer
   occurs.

Original Message:

 The external instantiation of std::string is a problem for libc++.
    Additions and removals of inline functions in string can cause ABI
    breakages, including introducing new symbols.

    This patch aims to:
      (1) Make clear which functions are explicitly instatiated.
      (2) Prevent new functions from being accidentally instantiated.
      (3) Allow a migration path for adding or removing functions from the
      explicit instantiation over time.

    Although this new formulation is uglier, it is preferable from a
    maintainability and readability standpoint because it explicitly
    enumerates the functions we've chosen to expose in our ABI. Changing
    this list is non-trivial and requires thought and planning.

    (3) is achieved by making it possible to control the extern template declaration
    separately from it's definition. Meaning we could add a new definition to
    the dylib, wait for it to roll out, then add the extern template
    declaration to the header. Similarly, we could remove existing extern
    template declarations while still keeping the definition to prevent ABI
    breakages.
This commit is contained in:
Eric Fiselier 2020-01-15 17:12:09 -05:00
parent 2d8f23f571
commit 288a143639
4 changed files with 61 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
libcxx/include/__config
View File

@ -897,6 +897,10 @@ typedef unsigned int char32_t;
#define _LIBCPP_EXTERN_TEMPLATE2(...) extern template __VA_ARGS__;
#endif
#ifndef _LIBCPP_EXTERN_TEMPLATE_DEFINE
#define _LIBCPP_EXTERN_TEMPLATE_DEFINE(...) template __VA_ARGS__;
#endif
#if defined(__APPLE__) || defined(__FreeBSD__) || defined(_LIBCPP_MSVCRT_LIKE) || \
defined(__sun__) || defined(__NetBSD__) || defined(__CloudABI__)
#define _LIBCPP_LOCALE__L_EXTENSIONS 1

53
libcxx/include/__string
View File

@ -70,6 +70,59 @@ _LIBCPP_PUSH_MACROS
_LIBCPP_BEGIN_NAMESPACE_STD
// The the extern template ABI lists are kept outside of <string> to improve the
// readability of that header.
#define _LIBCPP_STRING_EXTERN_TEMPLATE_LIST(_Func, _CharType) \
_Func(_LIBCPP_FUNC_VIS basic_string<_CharType>& basic_string<_CharType>::replace(size_type, size_type, value_type const*, size_type)) \
_Func(_LIBCPP_FUNC_VIS basic_string<_CharType>::size_type basic_string<_CharType>::rfind(value_type const*, size_type, size_type) const) \
_Func(_LIBCPP_FUNC_VIS void basic_string<_CharType>::__init(value_type const*, size_type, size_type)) \
_Func(_LIBCPP_FUNC_VIS basic_string<_CharType>::basic_string(basic_string const&)) \
_Func(_LIBCPP_FUNC_VIS basic_string<_CharType>& basic_string<_CharType>::replace(size_type, size_type, value_type const*)) \
_Func(_LIBCPP_FUNC_VIS basic_string<_CharType>::basic_string(basic_string const&, std::allocator<_CharType> const&)) \
_Func(_LIBCPP_FUNC_VIS basic_string<_CharType>::size_type basic_string<_CharType>::find_last_not_of(value_type const*, size_type, size_type) const) \
_Func(_LIBCPP_FUNC_VIS basic_string<_CharType>::~basic_string()) \
_Func(_LIBCPP_FUNC_VIS basic_string<_CharType>::size_type basic_string<_CharType>::find_first_not_of(value_type const*, size_type, size_type) const) \
_Func(_LIBCPP_FUNC_VIS basic_string<_CharType>& basic_string<_CharType>::insert(size_type, size_type, value_type)) \
_Func(_LIBCPP_FUNC_VIS basic_string<_CharType>& basic_string<_CharType>::operator=(value_type)) \
_Func(_LIBCPP_FUNC_VIS void basic_string<_CharType>::__init(value_type const*, size_type)) \
_Func(_LIBCPP_FUNC_VIS const _CharType& basic_string<_CharType>::at(size_type) const) \
_Func(_LIBCPP_FUNC_VIS basic_string<_CharType>& basic_string<_CharType>::insert(size_type, value_type const*, size_type)) \
_Func(_LIBCPP_FUNC_VIS basic_string<_CharType>::size_type basic_string<_CharType>::find_first_of(value_type const*, size_type, size_type) const) \
_Func(_LIBCPP_FUNC_VIS basic_string<_CharType>& basic_string<_CharType>::replace(size_type, size_type, size_type, value_type)) \
_Func(_LIBCPP_FUNC_VIS basic_string<_CharType>& basic_string<_CharType>::assign(value_type const*, size_type)) \
_Func(_LIBCPP_FUNC_VIS void basic_string<_CharType>::reserve(size_type)) \
_Func(_LIBCPP_FUNC_VIS basic_string<_CharType>& basic_string<_CharType>::append(value_type const*, size_type)) \
_Func(_LIBCPP_FUNC_VIS basic_string<_CharType>& basic_string<_CharType>::assign(basic_string const&, size_type, size_type)) \
_Func(_LIBCPP_FUNC_VIS basic_string<_CharType>::size_type basic_string<_CharType>::copy(value_type*, size_type, size_type) const) \
_Func(_LIBCPP_FUNC_VIS basic_string<_CharType>::basic_string(basic_string const&, size_type, size_type, std::allocator<_CharType> const&)) \
_Func(_LIBCPP_FUNC_VIS basic_string<_CharType>::size_type basic_string<_CharType>::find(value_type, size_type) const) \
_Func(_LIBCPP_FUNC_VIS void basic_string<_CharType>::__init(size_type, value_type)) \
_Func(_LIBCPP_FUNC_VIS basic_string<_CharType>& basic_string<_CharType>::insert(size_type, value_type const*)) \
_Func(_LIBCPP_FUNC_VIS basic_string<_CharType>::size_type basic_string<_CharType>::find_last_of(value_type const*, size_type, size_type) const) \
_Func(_LIBCPP_FUNC_VIS void basic_string<_CharType>::__grow_by(size_type, size_type, size_type, size_type, size_type, size_type)) \
_Func(_LIBCPP_FUNC_VIS void basic_string<_CharType>::__grow_by_and_replace(size_type, size_type, size_type, size_type, size_type, size_type, value_type const*)) \
_Func(_LIBCPP_FUNC_VIS void basic_string<_CharType>::push_back(value_type)) \
_Func(_LIBCPP_FUNC_VIS basic_string<_CharType>& basic_string<_CharType>::append(size_type, value_type)) \
_Func(_LIBCPP_FUNC_VIS basic_string<_CharType>::size_type basic_string<_CharType>::rfind(value_type, size_type) const) \
_Func(_LIBCPP_FUNC_VIS const basic_string<_CharType>::size_type basic_string<_CharType>::npos) \
_Func(_LIBCPP_FUNC_VIS basic_string<_CharType>& basic_string<_CharType>::assign(size_type, value_type)) \
_Func(_LIBCPP_FUNC_VIS basic_string<_CharType>& basic_string<_CharType>::erase(size_type, size_type)) \
_Func(_LIBCPP_FUNC_VIS basic_string<_CharType>& basic_string<_CharType>::append(basic_string const&, size_type, size_type)) \
_Func(_LIBCPP_FUNC_VIS int basic_string<_CharType>::compare(value_type const*) const) \
_Func(_LIBCPP_FUNC_VIS int basic_string<_CharType>::compare(size_type, size_type, value_type const*) const) \
_Func(_LIBCPP_FUNC_VIS _CharType& basic_string<_CharType>::at(size_type)) \
_Func(_LIBCPP_FUNC_VIS basic_string<_CharType>& basic_string<_CharType>::assign(value_type const*)) \
_Func(_LIBCPP_FUNC_VIS basic_string<_CharType>::size_type basic_string<_CharType>::find(value_type const*, size_type, size_type) const) \
_Func(_LIBCPP_FUNC_VIS int basic_string<_CharType>::compare(size_type, size_type, basic_string const&, size_type, size_type) const) \
_Func(_LIBCPP_FUNC_VIS int basic_string<_CharType>::compare(size_type, size_type, value_type const*, size_type) const) \
_Func(_LIBCPP_FUNC_VIS basic_string<_CharType>& basic_string<_CharType>::operator=(basic_string const&)) \
_Func(_LIBCPP_FUNC_VIS basic_string<_CharType>& basic_string<_CharType>::append(value_type const*)) \
_Func(_LIBCPP_FUNC_VIS basic_string<_CharType>& basic_string<_CharType>::replace(size_type, size_type, basic_string const&, size_type, size_type)) \
_Func(_LIBCPP_FUNC_VIS basic_string<_CharType>::iterator basic_string<_CharType>::insert(basic_string::const_iterator, value_type)) \
_Func(_LIBCPP_FUNC_VIS void basic_string<_CharType>::resize(size_type, value_type)) \
_Func(_LIBCPP_FUNC_VIS basic_string<_CharType>& basic_string<_CharType>::insert(size_type, basic_string const&, size_type, size_type))
// char_traits
template <class _CharT>

4
libcxx/include/string
View File

@ -4333,8 +4333,8 @@ basic_string<_CharT, _Traits, _Allocator>::__subscriptable(const const_iterator*
#endif // _LIBCPP_DEBUG_LEVEL >= 2
_LIBCPP_EXTERN_TEMPLATE(class _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS basic_string<char>)
_LIBCPP_EXTERN_TEMPLATE(class _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS basic_string<wchar_t>)
_LIBCPP_STRING_EXTERN_TEMPLATE_LIST(_LIBCPP_EXTERN_TEMPLATE, char)
_LIBCPP_STRING_EXTERN_TEMPLATE_LIST(_LIBCPP_EXTERN_TEMPLATE, wchar_t)
#if _LIBCPP_STD_VER > 11
// Literal suffixes for basic_string [basic.string.literals]

4
libcxx/src/string.cpp
View File

@ -20,8 +20,8 @@ _LIBCPP_BEGIN_NAMESPACE_STD
template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS __basic_string_common<true>;
template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS basic_string<char>;
template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS basic_string<wchar_t>;
_LIBCPP_STRING_EXTERN_TEMPLATE_LIST(_LIBCPP_EXTERN_TEMPLATE_DEFINE, char)
_LIBCPP_STRING_EXTERN_TEMPLATE_LIST(_LIBCPP_EXTERN_TEMPLATE_DEFINE, wchar_t)
template
string