I did this a long time ago with a janky python script, but now clang-format has built-in support for this. I fed clang-format every line with a #include and let it re-sort things according to the precise LLVM rules for include ordering baked into clang-format these days. I've reverted a number of files where the results of sorting includes isn't healthy. Either places where we have legacy code relying on particular include ordering (where possible, I'll fix these separately) or where we have particular formatting around #include lines that I didn't want to disturb in this patch. This patch is *entirely* mechanical. If you get merge conflicts or anything, just ignore the changes in this patch and run clang-format over your #include lines in the files. Sorry for any noise here, but it is important to keep these things stable. I was seeing an increasing number of patches with irrelevant re-ordering of #include lines because clang-format was used. This patch at least isolates that churn, makes it easy to skip when resolving conflicts, and gets us to a clean baseline (again). llvm-svn: 304787
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.