Re: [committed 1/2] libstdc++: Fix multiple definitions of std::exception_ptr functions [PR 97729]

[Jonathan Wakely <jwakely@redhat.com>]

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On 05/11/20 18:03 +0000, Jonathan Wakely wrote:
>This fixes some multiple definition errors caused by the changes for
>PR libstdc++/90295. The previous solution for inlining the members of
>std::exception_ptr but still exporting them from the library was to
>suppress the 'inline' keyword on those functions when compiling
>libsupc++/eh_ptr.cc, so they get defined in that file. That produces ODR
>violations though, because there are now both inline and non-inline
>definitions in the library, due to the use of std::exception_ptr in
>other files sucg as src/c++11/future.cc.
>
>The new solution is to define all the relevant members as 'inline'
>unconditionally, but use __attribute__((used)) to cause definitions to
>be emitted in libsupc++/eh_ptr.cc as before. This doesn't quite work
>however, because PR c++/67453 means the attribute is ignored on
>constructors and destructors. As a workaround, the old solution
>(conditionally inline) is still used for those members, but they are
>given the always_inline attribute so that they aren't emitted in
>src/c++11/future.o as inline definitions.

That workaround can be removed now.

Tested powerpc64le-linux. Committed to trunk.



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commit 0af3930a497e022597a08fa1bcef5e453bfa636f
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Mon Nov 9 10:16:07 2020

    libstdc++: Use 'inline' consistently in std::exception_ptr [PR 97729]
    
    With PR c++/67453 fixed we can rely on the 'used' attribute to emit
    inline constructors and destructors in libsupc++/eh_ptr.cc. This means
    we don't need to suppress the 'inline' keyword on them in that file, and
    don't need to force 'always_inline' on them in other files.
    
    libstdc++-v3/ChangeLog:
    
            PR libstdc++/97729
            * libsupc++/exception_ptr.h (exception_ptr::exception_ptr())
            (exception_ptr::exception_ptr(const exception_ptr&))
            (exception_ptr::~exception_ptr()): Remove 'always_inline'
            attributes. Use 'inline' unconditionally.

diff --git a/libstdc++-v3/libsupc++/exception_ptr.h b/libstdc++-v3/libsupc++/exception_ptr.h
index 001343ac0498..6ae4d4ca944d 100644
--- a/libstdc++-v3/libsupc++/exception_ptr.h
+++ b/libstdc++-v3/libsupc++/exception_ptr.h
@@ -174,19 +174,13 @@ namespace std
     };
 
     _GLIBCXX_EH_PTR_USED
-#ifndef  _GLIBCXX_EH_PTR_COMPAT
-    __attribute__((__always_inline__)) // XXX see PR 97729
     inline
-#endif
     exception_ptr::exception_ptr() _GLIBCXX_NOEXCEPT
     : _M_exception_object(0)
     { }
 
     _GLIBCXX_EH_PTR_USED
-#ifndef  _GLIBCXX_EH_PTR_COMPAT
-    __attribute__((__always_inline__))
     inline
-#endif
     exception_ptr::exception_ptr(const exception_ptr& __other) _GLIBCXX_NOEXCEPT
     : _M_exception_object(__other._M_exception_object)
     {
@@ -195,10 +189,7 @@ namespace std
     }
 
     _GLIBCXX_EH_PTR_USED
-#ifndef  _GLIBCXX_EH_PTR_COMPAT
-    __attribute__((__always_inline__))
     inline
-#endif
     exception_ptr::~exception_ptr() _GLIBCXX_USE_NOEXCEPT
     {
       if (_M_exception_object)