tree f5d84c95c272df59f339ee4d63878468359a5999
parent de39d1752f1559060237f158e47af6527d5e4abe
author Argyrios Kyrtzidis <akyrtzi@gmail.com> 1355434703 +0000
committer Argyrios Kyrtzidis <akyrtzi@gmail.com> 1355434703 +0000

[PCH] Make the new PCH format (control block) backwards compatible and
don't crash when loading a PCH with the older format.

The introduction of the control block broke compatibility with PCHs from
older versions. This patch allows loading (and rejecting) PCHs from an older
version and allows newer PCHs to be rejected from older clang versions as well.

rdar://12821386

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@170150 91177308-0d34-0410-b5e6-96231b3b80d8