r240247 - ASTReader: Treat InputFileOffsets as unaligned to avoid UB

[Justin Bogner]

Author: bogner
Date: Sun Jun 21 15:32:40 2015
New Revision: 240247

URL: http://llvm.org/viewvc/llvm-project?rev=240247&view=rev
Log:
ASTReader: Treat InputFileOffsets as unaligned to avoid UB

This is a better approach to fixing the undefined behaviour I tried to
fix in r240228. This data doesn't necessarily have suitable alignment
for uint64_t, so use unaligned_uint64_t instead.

This fixes 225 test failures when clang is built with ubsan.

Modified:
    cfe/trunk/include/clang/Serialization/Module.h
    cfe/trunk/lib/Serialization/ASTReader.cpp

Modified: cfe/trunk/include/clang/Serialization/Module.h
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Serialization/Module.h?rev=240247&r1=240246&r2=240247&view=diff
==============================================================================
--- cfe/trunk/include/clang/Serialization/Module.h (original)
+++ cfe/trunk/include/clang/Serialization/Module.h Sun Jun 21 15:32:40 2015
@@ -20,6 +20,7 @@
 #include "clang/Serialization/ContinuousRangeMap.h"
 #include "llvm/ADT/SetVector.h"
 #include "llvm/Bitcode/BitstreamReader.h"
+#include "llvm/Support/Endian.h"
 #include <memory>
 #include <string>
 
@@ -206,7 +207,7 @@ public:
   llvm::BitstreamCursor InputFilesCursor;
 
   /// \brief Offsets for all of the input file entries in the AST file.
-  const uint64_t *InputFileOffsets;
+  const llvm::support::unaligned_uint64_t *InputFileOffsets;
 
   /// \brief The input files that have been loaded from this AST file.
   std::vector<InputFile> InputFilesLoaded;

Modified: cfe/trunk/lib/Serialization/ASTReader.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Serialization/ASTReader.cpp?rev=240247&r1=240246&r2=240247&view=diff
==============================================================================
--- cfe/trunk/lib/Serialization/ASTReader.cpp (original)
+++ cfe/trunk/lib/Serialization/ASTReader.cpp Sun Jun 21 15:32:40 2015
@@ -2307,7 +2307,8 @@ ASTReader::ReadControlBlock(ModuleFile &
     case INPUT_FILE_OFFSETS:
       NumInputs = Record[0];
       NumUserInputs = Record[1];
-      F.InputFileOffsets = (const uint64_t *)Blob.data();
+      F.InputFileOffsets =
+          (const llvm::support::unaligned_uint64_t *)Blob.data();
       F.InputFilesLoaded.resize(NumInputs);
       break;
     }