https://llvm.org/bugs/show_bug.cgi?id=27556
Bug ID: 27556
Summary: shared_ptr issues when allocator/deleter have throwing
move constructor
Product: libc++
Version: unspecified
Hardware: PC
OS: All
Status: NEW
Severity: normal
Priority: P
Component: All Bugs
Assignee: unassignedclangb...@nondot.org
Reporter: klemensb...@gmail.com
CC: llvm-bugs@lists.llvm.org, mclow.li...@gmail.com
Classification: Unclassified
There seems to be an issue in the shared_ptr implementation if the move
constructor of the deleter and/or allocator throw an exception. The standard
only guarantees that the copy constructor of the allocator and deleter may not
throw, nothing in there talks about move constructors.
In <memory>, line 4185, the allocator and deleter get passed into the _CntrlBlk
aka __shared_ptr_pointer by copy, which is fine and will not throw (note:
instead of always copying, we could use std::move_if_noexcept here).
The __shared_ptr_pointer constructor hands off the deleter and allocator into
the __compressed_pair by unconditional move (!). This can throw, and at line
4191, __d could already be moved-from or partially moved-from.
I think these calls to std::move should be replaced with std::move_if_noexcept.
There are more move constructors being invoked inside __compressed_pair, which
will also need to get looked at.
Line numbers refer to SVN revision 267901.
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