[libc++] Add _LIBCPP_EXTERN_TEMPLATE_INLINE_VISIBILITY to support GCC ABI compatibility
Summary:
GCC and Clang handle visibility attributes on the out-of-line definition of externally instantiated templates differently. For example in the reproducer below Clang will emit both 'foo' and 'bar' with default visibility while GCC only emits a non-hidden 'foo'.
```
// RUN: g++ -std=c++11 -shared -O3 test.cpp && sym_extract.py a.out
// RUN: clang++ -std=c++11 -shared -O3 test.cpp && sym_extract.py a.out
#define INLINE_VISIBILITY __attribute__((visibility("hidden"), always_inline))
template <class T>
struct Foo {
void foo();
void bar();
};
template <class T>
void Foo<T>::foo() {}
template <class T>
inline INLINE_VISIBILITY
void Foo<T>::bar() {}
template struct Foo<int>;
```
This difference creates ABI incompatibilities between Clang and GCC built dylibs. Specifically GCC built dylibs lack definitions for various member functions of `basic_string`, `basic_istream`, `basic_ostream`, `basic_iostream`, and `basic_streambuf` (All of these types are externally instantiated).
Surprisingly these missing symbols don't cause many problems because the functions are marked `always_inline` therefore the dylib definition is rarely needed. However when an out-of-line definition is required then GCC built dylibs will fail to link. For example [GCC built dylibs cannot build Clang](http://stackoverflow.com/questions/39454262/clang-build-errors).
This patch works around this issue by adding `_LIBCPP_EXTERN_TEMPLATE_INLINE_VISIBILITY` which is used to mark externally instantiated member functions as always inline. When building the library `_LIBCPP_EXTERN_TEMPLATE_INLINE_VISIBILITY` sets the symbol's visibility to "default" instead of "hidden", otherwise it acts exactly the same as `_LIBCPP_INLINE_VISIBILITY`.
After applying this patch GCC dylibs now contain:
* `_ZNSt3__115basic_streambufIcNS_11char_traitsIcEEE7sungetcEv`
* `_ZNSt3__115basic_streambufIwNS_11char_traitsIwEEE5gbumpEi`
* `_ZNSt3__115basic_streambufIwNS_11char_traitsIwEEE7sungetcEv`
* `_ZNSt3__115basic_streambufIcNS_11char_traitsIcEEE9sputbackcEc`
* `_ZNSt3__113basic_istreamIwNS_11char_traitsIwEEE3getERNS_15basic_streambufIwS2_EE`
* `_ZNSt3__113basic_ostreamIwNS_11char_traitsIwEEElsEPFRNS_9basic_iosIwS2_EES6_E`
* `_ZNSt3__115basic_streambufIcNS_11char_traitsIcEEE4setpEPcS4_`
* `_ZNSt3__113basic_ostreamIwNS_11char_traitsIwEEEC1EPNS_15basic_streambufIwS2_EE`
* `_ZNSt3__115basic_streambufIcNS_11char_traitsIcEEE6snextcEv`
* `_ZNSt3__113basic_istreamIcNS_11char_traitsIcEEE4swapERS3_`
* `_ZNSt3__113basic_istreamIwNS_11char_traitsIwEEE4swapERS3_`
* `_ZNSt3__112basic_stringIcNS_11char_traitsIcEENS_9allocatorIcEEE6__initEPKcm`
* `_ZNSt3__113basic_istreamIcNS_11char_traitsIcEEErsEPFRNS_8ios_baseES5_E`
* `_ZNSt3__115basic_streambufIcNS_11char_traitsIcEEE9pubsetbufEPcl`
* `_ZNSt3__115basic_streambufIcNS_11char_traitsIcEEE10pubseekoffExNS_8ios_base7seekdirEj`
* `_ZNSt3__113basic_istreamIwNS_11char_traitsIwEEErsEPFRNS_9basic_iosIwS2_EES6_E`
* `_ZNSt3__115basic_streambufIwNS_11char_traitsIwEEE5pbumpEi`
* `_ZNSt3__113basic_ostreamIcNS_11char_traitsIcEEE5seekpENS_4fposI11__mbstate_tEE`
* `_ZNSt3__113basic_istreamIcNS_11char_traitsIcEEE7getlineEPcl`
* `_ZNSt3__115basic_streambufIcNS_11char_traitsIcEEE5sgetcEv`
* `_ZNSt3__113basic_istreamIcNS_11char_traitsIcEEE3getERNS_15basic_streambufIcS2_EE`
* `_ZNSt3__113basic_ostreamIcNS_11char_traitsIcEEElsEPFRNS_8ios_baseES5_E`
* `_ZNSt3__115basic_streambufIcNS_11char_traitsIcEEE8in_availEv`
* `_ZNSt3__113basic_istreamIwNS_11char_traitsIwEEErsEPFRNS_8ios_baseES5_E`
* `_ZNSt3__115basic_streambufIcNS_11char_traitsIcEEE6sbumpcEv`
* `_ZNSt3__113basic_ostreamIcNS_11char_traitsIcEEElsEPFRNS_9basic_iosIcS2_EES6_E`
* `_ZNSt3__113basic_istreamIcNS_11char_traitsIcEEE3getERc`
* `_ZNSt3__115basic_streambufIwNS_11char_traitsIwEEE6snextcEv`
* `_ZNSt3__112basic_stringIwNS_11char_traitsIwEENS_9allocatorIwEEE6__initEmw`
* `_ZNSt3__113basic_istreamIwNS_11char_traitsIwEEE7getlineEPwl`
* `_ZNSt3__113basic_ostreamIcNS_11char_traitsIcEEE5tellpEv`
* `_ZNSt3__113basic_istreamIwNS_11char_traitsIwEEE3getERw`
* `_ZNSt3__112basic_stringIcNS_11char_traitsIcEENS_9allocatorIcEEE6__initEmc`
* `_ZNSt3__115basic_streambufIcNS_11char_traitsIcEEE7pubsyncEv`
* `_ZNSt3__113basic_istreamIcNS_11char_traitsIcEEE3getEPcl`
* `_ZNSt3__113basic_istreamIcNS_11char_traitsIcEEEC2EPNS_15basic_streambufIcS2_EE`
* `_ZNSt3__113basic_istreamIcNS_11char_traitsIcEEErsEPFRNS_9basic_iosIcS2_EES6_E`
* `_ZNSt3__115basic_streambufIwNS_11char_traitsIwEEE7pubsyncEv`
* `_ZNSt3__115basic_streambufIcNS_11char_traitsIcEEE5sputcEc`
* `_ZNSt3__113basic_ostreamIwNS_11char_traitsIwEEE5seekpExNS_8ios_base7seekdirE`
* `_ZNKSt3__115basic_streambufIcNS_11char_traitsIcEEE6getlocEv`
* `_ZNSt3__115basic_streambufIcNS_11char_traitsIcEEE5gbumpEi`
* `_ZNSt3__114basic_iostreamIcNS_11char_traitsIcEEE4swapERS3_`
* `_ZNSt3__113basic_ostreamIwNS_11char_traitsIwEEE5seekpENS_4fposI11__mbstate_tEE`
* `_ZNSt3__113basic_ostreamIwNS_11char_traitsIwEEE5tellpEv`
* `_ZNSt3__113basic_ostreamIwNS_11char_traitsIwEEElsEPFRS3_S4_E`
* `_ZNSt3__113basic_istreamIwNS_11char_traitsIwEEE3getEPwl`
* `_ZNSt3__113basic_istreamIwNS_11char_traitsIwEEEC2EPNS_15basic_streambufIwS2_EE`
* `_ZNSt3__113basic_ostreamIcNS_11char_traitsIcEEElsEPFRS3_S4_E`
* `_ZNSt3__115basic_streambufIcNS_11char_traitsIcEEE4setgEPcS4_S4_`
* `_ZNSt3__112basic_stringIwNS_11char_traitsIwEENS_9allocatorIwEEE6__initEPKwmm`
* `_ZNSt3__115basic_streambufIwNS_11char_traitsIwEEE4setgEPwS4_S4_`
* `_ZNSt3__113basic_istreamIwNS_11char_traitsIwEEEC1EPNS_15basic_streambufIwS2_EE`
* `_ZNSt3__115basic_streambufIcNS_11char_traitsIcEEE8pubimbueERKNS_6localeE`
* `_ZNSt3__113basic_ostreamIcNS_11char_traitsIcEEE4swapERS3_`
* `_ZNSt3__113basic_ostreamIwNS_11char_traitsIwEEEC2EPNS_15basic_streambufIwS2_EE`
* `_ZNSt3__115basic_streambufIwNS_11char_traitsIwEEE10pubseekposENS_4fposI11__mbstate_tEEj`
* `_ZNSt3__115basic_streambufIcNS_11char_traitsIcEEE5pbumpEi`
* `_ZNSt3__115basic_streambufIwNS_11char_traitsIwEEE5sgetcEv`
* `_ZNSt3__113basic_ostreamIwNS_11char_traitsIwEEE4swapERS3_`
* `_ZNSt3__115basic_streambufIcNS_11char_traitsIcEEE10pubseekposENS_4fposI11__mbstate_tEEj`
* `_ZNSt3__115basic_streambufIcNS_11char_traitsIcEEE5sputnEPKcl`
* `_ZNSt3__113basic_ostreamIcNS_11char_traitsIcEEE5seekpExNS_8ios_base7seekdirE`
* `_ZNSt3__115basic_streambufIwNS_11char_traitsIwEEE5sgetnEPwl`
* `_ZNSt3__113basic_ostreamIwNS_11char_traitsIwEEElsEPFRNS_8ios_baseES5_E`
* `_ZNSt3__115basic_streambufIwNS_11char_traitsIwEEE4setpEPwS4_`
* `_ZNSt3__115basic_streambufIcNS_11char_traitsIcEEE5sgetnEPcl`
* `_ZNKSt3__115basic_streambufIwNS_11char_traitsIwEEE6getlocEv`
* `_ZNSt3__114basic_iostreamIcNS_11char_traitsIcEEEC2EPNS_15basic_streambufIcS2_EE`
* `_ZNSt3__115basic_streambufIwNS_11char_traitsIwEEE8pubimbueERKNS_6localeE`
* `_ZNSt3__114basic_iostreamIcNS_11char_traitsIcEEEC1EPNS_15basic_streambufIcS2_EE`
* `_ZNSt3__115basic_streambufIwNS_11char_traitsIwEEE8in_availEv`
* `_ZNSt3__113basic_istreamIcNS_11char_traitsIcEEEC1EPNS_15basic_streambufIcS2_EE`
* `_ZNSt3__112basic_stringIcNS_11char_traitsIcEENS_9allocatorIcEEE6__initEPKcmm`
* `_ZNSt3__115basic_streambufIwNS_11char_traitsIwEEE6sbumpcEv`
* `_ZNSt3__115basic_streambufIwNS_11char_traitsIwEEE10pubseekoffExNS_8ios_base7seekdirEj`
* `_ZNSt3__113basic_ostreamIcNS_11char_traitsIcEEEC2EPNS_15basic_streambufIcS2_EE`
* `_ZNSt3__113basic_istreamIwNS_11char_traitsIwEEErsEPFRS3_S4_E`
* `_ZNSt3__115basic_streambufIwNS_11char_traitsIwEEE9sputbackcEw`
* `_ZNSt3__112basic_stringIwNS_11char_traitsIwEENS_9allocatorIwEEE6__initEPKwm`
* `_ZNSt3__115basic_streambufIwNS_11char_traitsIwEEE5sputnEPKwl`
* `_ZNSt3__113basic_istreamIcNS_11char_traitsIcEEErsEPFRS3_S4_E`
* `_ZNSt3__113basic_ostreamIcNS_11char_traitsIcEEEC1EPNS_15basic_streambufIcS2_EE`
* `_ZNSt3__115basic_streambufIwNS_11char_traitsIwEEE9pubsetbufEPwl`
* `_ZNSt3__115basic_streambufIwNS_11char_traitsIwEEE5sputcEw`
This patch has no effect on Clang based builds.
Reviewers: mclow.lists, eugenis, danalbert, jroelofs, EricWF
Subscribers: beanz, cfe-commits, mgorny
Differential Revision: https://reviews.llvm.org/D24600
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@281681 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/ostream b/include/ostream
index 3a4c218..cf20514 100644
--- a/include/ostream
+++ b/include/ostream
@@ -160,20 +160,24 @@
typedef typename traits_type::off_type off_type;
// 27.7.2.2 Constructor/destructor:
- explicit basic_ostream(basic_streambuf<char_type, traits_type>* __sb);
+ inline _LIBCPP_EXTERN_TEMPLATE_INLINE_VISIBILITY
+ explicit basic_ostream(basic_streambuf<char_type, traits_type>* __sb)
+ { this->init(__sb); }
virtual ~basic_ostream();
protected:
#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
- _LIBCPP_INLINE_VISIBILITY
+ inline _LIBCPP_INLINE_VISIBILITY
basic_ostream(basic_ostream&& __rhs);
#endif
// 27.7.2.3 Assign/swap
#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
- _LIBCPP_INLINE_VISIBILITY
+ inline _LIBCPP_INLINE_VISIBILITY
basic_ostream& operator=(basic_ostream&& __rhs);
#endif
- void swap(basic_ostream& __rhs);
+ inline _LIBCPP_EXTERN_TEMPLATE_INLINE_VISIBILITY
+ void swap(basic_ostream& __rhs)
+ { basic_ios<char_type, traits_type>::swap(__rhs); }
#ifndef _LIBCPP_HAS_NO_DELETED_FUNCTIONS
basic_ostream (const basic_ostream& __rhs) = delete;
@@ -188,10 +192,19 @@
class _LIBCPP_TYPE_VIS_ONLY sentry;
// 27.7.2.6 Formatted output:
- basic_ostream& operator<<(basic_ostream& (*__pf)(basic_ostream&));
+ inline _LIBCPP_EXTERN_TEMPLATE_INLINE_VISIBILITY
+ basic_ostream& operator<<(basic_ostream& (*__pf)(basic_ostream&))
+ { return __pf(*this); }
+
+ inline _LIBCPP_EXTERN_TEMPLATE_INLINE_VISIBILITY
basic_ostream& operator<<(basic_ios<char_type, traits_type>&
- (*__pf)(basic_ios<char_type,traits_type>&));
- basic_ostream& operator<<(ios_base& (*__pf)(ios_base&));
+ (*__pf)(basic_ios<char_type,traits_type>&))
+ { __pf(*this); return *this; }
+
+ inline _LIBCPP_EXTERN_TEMPLATE_INLINE_VISIBILITY
+ basic_ostream& operator<<(ios_base& (*__pf)(ios_base&))
+ { __pf(*this); return *this; }
+
basic_ostream& operator<<(bool __n);
basic_ostream& operator<<(short __n);
basic_ostream& operator<<(unsigned short __n);
@@ -213,8 +226,11 @@
basic_ostream& flush();
// 27.7.2.5 seeks:
+ inline _LIBCPP_EXTERN_TEMPLATE_INLINE_VISIBILITY
pos_type tellp();
+ inline _LIBCPP_EXTERN_TEMPLATE_INLINE_VISIBILITY
basic_ostream& seekp(pos_type __pos);
+ inline _LIBCPP_EXTERN_TEMPLATE_INLINE_VISIBILITY
basic_ostream& seekp(off_type __off, ios_base::seekdir __dir);
protected:
@@ -274,24 +290,15 @@
}
}
-template <class _CharT, class _Traits>
-inline _LIBCPP_INLINE_VISIBILITY
-basic_ostream<_CharT, _Traits>::basic_ostream(basic_streambuf<char_type, traits_type>* __sb)
-{
- this->init(__sb);
-}
-
#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
template <class _CharT, class _Traits>
-inline _LIBCPP_INLINE_VISIBILITY
basic_ostream<_CharT, _Traits>::basic_ostream(basic_ostream&& __rhs)
{
this->move(__rhs);
}
template <class _CharT, class _Traits>
-inline _LIBCPP_INLINE_VISIBILITY
basic_ostream<_CharT, _Traits>&
basic_ostream<_CharT, _Traits>::operator=(basic_ostream&& __rhs)
{
@@ -307,41 +314,6 @@
}
template <class _CharT, class _Traits>
-inline _LIBCPP_INLINE_VISIBILITY
-void
-basic_ostream<_CharT, _Traits>::swap(basic_ostream& __rhs)
-{
- basic_ios<char_type, traits_type>::swap(__rhs);
-}
-
-template <class _CharT, class _Traits>
-inline _LIBCPP_INLINE_VISIBILITY
-basic_ostream<_CharT, _Traits>&
-basic_ostream<_CharT, _Traits>::operator<<(basic_ostream& (*__pf)(basic_ostream&))
-{
- return __pf(*this);
-}
-
-template <class _CharT, class _Traits>
-inline _LIBCPP_INLINE_VISIBILITY
-basic_ostream<_CharT, _Traits>&
-basic_ostream<_CharT, _Traits>::operator<<(basic_ios<char_type, traits_type>&
- (*__pf)(basic_ios<char_type,traits_type>&))
-{
- __pf(*this);
- return *this;
-}
-
-template <class _CharT, class _Traits>
-inline _LIBCPP_INLINE_VISIBILITY
-basic_ostream<_CharT, _Traits>&
-basic_ostream<_CharT, _Traits>::operator<<(ios_base& (*__pf)(ios_base&))
-{
- __pf(*this);
- return *this;
-}
-
-template <class _CharT, class _Traits>
basic_ostream<_CharT, _Traits>&
basic_ostream<_CharT, _Traits>::operator<<(basic_streambuf<char_type, traits_type>* __sb)
{
@@ -989,7 +961,6 @@
}
template <class _CharT, class _Traits>
-inline _LIBCPP_INLINE_VISIBILITY
typename basic_ostream<_CharT, _Traits>::pos_type
basic_ostream<_CharT, _Traits>::tellp()
{
@@ -999,7 +970,6 @@
}
template <class _CharT, class _Traits>
-inline _LIBCPP_INLINE_VISIBILITY
basic_ostream<_CharT, _Traits>&
basic_ostream<_CharT, _Traits>::seekp(pos_type __pos)
{
@@ -1013,7 +983,6 @@
}
template <class _CharT, class _Traits>
-inline _LIBCPP_INLINE_VISIBILITY
basic_ostream<_CharT, _Traits>&
basic_ostream<_CharT, _Traits>::seekp(off_type __off, ios_base::seekdir __dir)
{