f9cd2ee119
Add MappedFileRegionArena which can be served as a file system backed persistent memory allocator. The allocator works like a BumpPtrAllocator, and is designed to be thread safe and process safe. The implementation relies on the POSIX compliance of file system and doesn't work on all file systems. If the file system supports lazy tail (doesn't allocate disk space if the tail of the large file is not used), user has more flexibility to declare a larger capacity. The allocator works by using a atomically updated bump ptr at a location that can be customized by the user. The atomic pointer points to the next available space to allocate, and the allocator will resize/truncate to current usage once all clients closed the allocator. Windows implementation contributed by: @hjyamauchi
llvm/lib/Support/Unix README =========================== This directory provides implementations of the lib/System classes that are common to two or more variants of UNIX. For example, the directory structure underneath this directory could look like this: Unix - only code that is truly generic to all UNIX platforms Posix - code that is specific to Posix variants of UNIX SUS - code that is specific to the Single Unix Specification SysV - code that is specific to System V variants of UNIX As a rule, only those directories actually needing to be created should be created. Also, further subdirectories could be created to reflect versions of the various standards. For example, under SUS there could be v1, v2, and v3 subdirectories to reflect the three major versions of SUS.