[PATCH] PR libstdc++/85812 fix memory leak in std::make_exception_ptr

[Jonathan Wakely <jwakely at redhat dot com>]

As the PR points out, the constructor called in the placement new
expression can throw, in which case the allocation would be leaked.

Separating the two implementations makes it much easier to read what
the code is doing.

	PR libstdc++/85812
	* libsupc++/cxxabi_init_exception.h (__cxa_free_exception): Declare.
	* libsupc++/exception_ptr.h (make_exception_ptr) [__cpp_exceptions]:
	Refactor to separate non-throwing and throwing implementations.
	[__cpp_rtti && !_GLIBCXX_HAVE_CDTOR_CALLABI]: Deallocate the memory
	if constructing the object throws.

Tested powerpc64le-linux (and also using ASan to verify the fix).
Committed to trunk. Backports to gcc-7 and gcc-8 will follow.

Attachment: patch.txt
Description: Text document