r240228 - ASTReader: Copy input file offset data to avoid unaligned accesses

[Rafael Espíndola]

Or make sure it is aligned when writing?
On Jun 20, 2015 8:12 PM, "David Majnemer" <david.majnemer at gmail.com> wrote:

>
>
> On Sat, Jun 20, 2015 at 5:01 PM, Richard Smith <richard at metafoo.co.uk>
> wrote:
>
>> Can we fix the users of this pointer instead of eagerly making a copy of
>> the data?
>>
> What if we made it a pointer to a `unaligned_int64_t` ?
>
>
>
>> On 20 Jun 2015 3:38 pm, "Justin Bogner" <mail at justinbogner.com> wrote:
>>
>>> Author: bogner
>>> Date: Sat Jun 20 17:31:04 2015
>>> New Revision: 240228
>>>
>>> URL: http://llvm.org/viewvc/llvm-project?rev=240228&view=rev
>>> <https://urldefense.proofpoint.com/v2/url?u=http-3A__llvm.org_viewvc_llvm-2Dproject-3Frev-3D240228-26view-3Drev&d=AwMFaQ&c=8hUWFZcy2Z-Za5rBPlktOQ&r=BSqEv9KvKMW_Ob8SyngJ70KdZISM_ASROnREeq0cCxk&m=kwYaPbS8NymK3f4XcSSPr5rBO1qeeQW2OEGEKsM-li8&s=koDwMVglgVCexLBKJTYHBAIUdecCmplqByqsswIwgoA&e=>
>>> Log:
>>> ASTReader: Copy input file offset data to avoid unaligned accesses
>>>
>>> We interpret Blob as an array of uint64_t here, but there's no reason
>>> to think that it has suitable alignment. Instead, read the data in in
>>> an alignment-safe way and store it in a std::vector.
>>>
>>> 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=240228&r1=240227&r2=240228&view=diff
>>> <https://urldefense.proofpoint.com/v2/url?u=http-3A__llvm.org_viewvc_llvm-2Dproject_cfe_trunk_include_clang_Serialization_Module.h-3Frev-3D240228-26r1-3D240227-26r2-3D240228-26view-3Ddiff&d=AwMFaQ&c=8hUWFZcy2Z-Za5rBPlktOQ&r=BSqEv9KvKMW_Ob8SyngJ70KdZISM_ASROnREeq0cCxk&m=kwYaPbS8NymK3f4XcSSPr5rBO1qeeQW2OEGEKsM-li8&s=kMj8_X2N1MPqBzUHrVblxdIvIopnoGjPlqHFTtUJRYE&e=>
>>>
>>> ==============================================================================
>>> --- cfe/trunk/include/clang/Serialization/Module.h (original)
>>> +++ cfe/trunk/include/clang/Serialization/Module.h Sat Jun 20 17:31:04
>>> 2015
>>> @@ -206,7 +206,7 @@ public:
>>>    llvm::BitstreamCursor InputFilesCursor;
>>>
>>>    /// \brief Offsets for all of the input file entries in the AST file.
>>> -  const uint64_t *InputFileOffsets;
>>> +  std::vector<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=240228&r1=240227&r2=240228&view=diff
>>> <https://urldefense.proofpoint.com/v2/url?u=http-3A__llvm.org_viewvc_llvm-2Dproject_cfe_trunk_lib_Serialization_ASTReader.cpp-3Frev-3D240228-26r1-3D240227-26r2-3D240228-26view-3Ddiff&d=AwMFaQ&c=8hUWFZcy2Z-Za5rBPlktOQ&r=BSqEv9KvKMW_Ob8SyngJ70KdZISM_ASROnREeq0cCxk&m=kwYaPbS8NymK3f4XcSSPr5rBO1qeeQW2OEGEKsM-li8&s=tYyGueRSfeVqYs8IooPMDV7_HNeh_uYnKyH87aCm5rI&e=>
>>>
>>> ==============================================================================
>>> --- cfe/trunk/lib/Serialization/ASTReader.cpp (original)
>>> +++ cfe/trunk/lib/Serialization/ASTReader.cpp Sat Jun 20 17:31:04 2015
>>> @@ -2304,13 +2304,21 @@ ASTReader::ReadControlBlock(ModuleFile &
>>>          return Result;
>>>        break;
>>>
>>> -    case INPUT_FILE_OFFSETS:
>>> +    case INPUT_FILE_OFFSETS: {
>>>        NumInputs = Record[0];
>>>        NumUserInputs = Record[1];
>>> -      F.InputFileOffsets = (const uint64_t *)Blob.data();
>>> +      F.InputFileOffsets.clear();
>>> +      F.InputFileOffsets.reserve(NumInputs);
>>> +      using namespace llvm::support;
>>> +      const char *Buf = Blob.data();
>>> +      for (unsigned int I = 0; I < NumInputs; ++I)
>>> +        F.InputFileOffsets.push_back(
>>> +            endian::readNext<uint64_t, native, unaligned>(Buf));
>>> +
>>>        F.InputFilesLoaded.resize(NumInputs);
>>>        break;
>>>      }
>>> +    }
>>>    }
>>>  }
>>>
>>>
>>>
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>>
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