tree 0f496f250bcb2afe858d1a1106ca3d9b27bea210
parent df9f12fda6c9e67848aca9019048a2a06a8b1c9d
author Adrian Prantl <aprantl@apple.com> 1487307854 -0800
committer Adrian Prantl <aprantl@apple.com> 1487781742 -0800

Prevent nonrecoverable module-out-of-date errors in projects that mix
PCH and clang modules.

This patch introduces a NeededByPCHOrCompilationUsesPCH language
option which causes clang modules imported by PCH which goes into the
module hash, thus isolating them from rebuilds triggered by other
clang modules.  This patch further disables module validation for
modules imported by PCH, since there is no mechanism in clang to
rebuild ou-tof-date modules when they were imported by a PCH.

rdar://problem/30384801