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08-Dec-2012 |
Richard Smith <richard-llvm@metafoo.co.uk> |
Finish implementing 'selected constructor' rules for triviality in C++11. In
the cases where we can't determine whether special members would be trivial
while building the class, we eagerly declare those special members. The impact
of this is bounded, since it does not trigger implicit declarations of special
members in classes which merely *use* those classes.
In order to determine whether we need to apply this rule, we also need to
eagerly declare move operations and destructors in cases where they might be
deleted. If a move operation were supposed to be deleted, it would instead
be suppressed, and we could need overload resolution to determine if we fall
back to a trivial copy operation. If a destructor were implicitly deleted,
it would cause the move constructor of any derived classes to be suppressed.
As discussed on cxx-abi-dev, C++11's selected constructor rules are also
retroactively applied as a defect resolution in C++03 mode, in order to
identify that class B has a non-trivial copy constructor (since it calls
A's constructor template, not A's copy constructor):
struct A { template<typename T> A(T &); };
struct B { mutable A a; };
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@169673 91177308-0d34-0410-b5e6-96231b3b80d8
/external/clang/test/CXX/special/class.copy/p25-0x.cpp
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