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From: "lizekun.zek at bytedance dot com" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug c++/103490] New: Linkage type of typeinfo of polymorphic object with OOL functions Date: Tue, 30 Nov 2021 09:48:01 +0000 [thread overview] Message-ID: <bug-103490-4@http.gcc.gnu.org/bugzilla/> (raw) https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103490 Bug ID: 103490 Summary: Linkage type of typeinfo of polymorphic object with OOL functions Product: gcc Version: 11.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: c++ Assignee: unassigned at gcc dot gnu.org Reporter: lizekun.zek at bytedance dot com Target Milestone: --- Hi guys, I found that the linkage of typeinfo of polymorphic object with OOL-functions is weak, while that is strong for clang, and I want to attach a patch to make the behavior of the two compilers consistent. However, I can't find the clear definition of this in Itanium C++ ABI, so here are the questions: 1.It is easy to understand that we make the object with inlined-functions weak, because it usually appears in a header file and may be defined several times, so when functions are out-of-line, why do we make it weak? 2.In fact, I prefer the gcc way, are there any cases that show gcc is better? This is a case to show the issue. --- test.h class A{ public: virtual const int getA(){} ; virtual const int getB(){} ; }; --- testA.cpp #include<iostream> #include "test.h" using namespace std; class Test : public A { public: virtual const int getA() override; }; const int Test ::getA() { return 1; } int main() { A * t=new Test();; cout << dynamic_cast<Test*>(t); } --- testB.cpp #include "test.h" class Test : A { public: virtual const int getB() override; }; const int Test :: getB() { return 2; }
next reply other threads:[~2021-11-30 9:48 UTC|newest] Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-11-30 9:48 lizekun.zek at bytedance dot com [this message] 2021-12-20 23:27 ` [Bug c++/103490] " pinskia at gcc dot gnu.org 2021-12-21 0:02 ` pinskia at gcc dot gnu.org 2021-12-22 5:04 ` rjmccall at gmail dot com 2021-12-22 7:07 ` pinskia at gcc dot gnu.org
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