From: Justin Bogner <mail@justinbogner.com>
Date: Sun, 21 Jun 2015 20:32:40 +0000 (+0000)
Subject: ASTReader: Treat InputFileOffsets as unaligned to avoid UB
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=4d78fb0b89762e68fc87ab764cae20a1f5840ad4;p=clang

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.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@240247 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/include/clang/Serialization/Module.h b/include/clang/Serialization/Module.h
index 5571d91a54..c98ced41aa 100644
--- a/include/clang/Serialization/Module.h
+++ b/include/clang/Serialization/Module.h
@@ -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;
diff --git a/lib/Serialization/ASTReader.cpp b/lib/Serialization/ASTReader.cpp
index d75b5eb73d..7242793be2 100644
--- a/lib/Serialization/ASTReader.cpp
+++ b/lib/Serialization/ASTReader.cpp
@@ -2307,7 +2307,8 @@ ASTReader::ReadControlBlock(ModuleFile &F,
     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;
     }