Fix unaligned memory access when reading INPUT_FILE_OFFSETS data

Summary: The blob data is unaligned, so we also should read it as such. Should fix the random failures with the sanitizer builds.

Reviewers: rsmith, v.g.vassilev

Reviewed By: v.g.vassilev

Subscribers: cfe-commits

Differential Revision: https://reviews.llvm.org/D47247

llvm-svn: 333069
diff --git a/clang/lib/Serialization/ASTReader.cpp b/clang/lib/Serialization/ASTReader.cpp
index 8c8b878..8224236 100644
--- a/clang/lib/Serialization/ASTReader.cpp
+++ b/clang/lib/Serialization/ASTReader.cpp
@@ -4811,7 +4811,8 @@
 
       unsigned NumInputFiles = Record[0];
       unsigned NumUserFiles = Record[1];
-      const uint64_t *InputFileOffs = (const uint64_t *)Blob.data();
+      const llvm::support::unaligned_uint64_t *InputFileOffs =
+          (const llvm::support::unaligned_uint64_t *)Blob.data();
       for (unsigned I = 0; I != NumInputFiles; ++I) {
         // Go find this input file.
         bool isSystemFile = I >= NumUserFiles;