[PCH] Fix timestamp check on windows hosts.

On Linux, if the timestamp of a header file, included in the pch, is modified, then including the pch without regenerating it causes a fatal error, which is reasonable.
On Windows the check is ifdefed out, allowing the compilation to continue in a broken state.
The root of the broken state is that, if timestamps dont match, the preprocessor will reparse a header without discarding the pch data.
This leads to "#pragma once" header to be included twice.
The reason behind the ifdefing of the check lacks documentation, and was done 6 years ago.
This change tentatively removes the ifdefing.

First part of patch proposed at:

Differential Revision: http://reviews.llvm.org/D20867

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@275261 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Serialization/ASTReader.cpp b/lib/Serialization/ASTReader.cpp
index 80fef7d39e3cfc58f87c34009af187a3ea3caaf5..820f339a75df6519877ce40270956faea157f043 100644 (file)
--- a/lib/Serialization/ASTReader.cpp
+++ b/lib/Serialization/ASTReader.cpp
@@ -2010,17 +2010,8 @@ InputFile ASTReader::getInputFile(ModuleFile &F, unsigned ID, bool Complain) {
   // For an overridden file, there is nothing to validate.
   if (!Overridden && //
       (StoredSize != File->getSize() ||
-#if defined(LLVM_ON_WIN32)
-       false
-#else
-       // In our regression testing, the Windows file system seems to
-       // have inconsistent modification times that sometimes
-       // erroneously trigger this error-handling path.
-       //
-       // FIXME: This probably also breaks HeaderFileInfo lookups on Windows.
        (StoredTime && StoredTime != File->getModificationTime() &&
         !DisableValidation)
-#endif
        )) {
     if (Complain) {
       // Build a list of the PCH imports that got us here (in reverse).