[llvm] r217325 - [MCJIT] Fix a bug RuntimeDyldImpl's read/writeBytesUnaligned methods.

[Lang Hames]

That's one of the intents of the RuntimeDyldChecker framework: Tests for
any any target can be executed and verified on any host. As you surmised
the code is never actually run, just loaded and linked, then inspected
according to the check expressions.

- Lang.

On Mon, Sep 8, 2014 at 11:23 AM, David Blaikie <dblaikie at gmail.com> wrote:

>
>
> On Mon, Sep 8, 2014 at 10:56 AM, Lang Hames <lhames at gmail.com> wrote:
>
>> I'm not sure I'd add a function for that, though you could use an
>> "increment" variable to merge the loops if you like. I don't think it's
>> really worth it though.
>>
>> The commit message could have been clearer, but this is certainly
>> testable: It's is an attempt to get the RuntimeDyld regression tests
>> working on PPC.
>>
>
> Can those tests be run on other platforms with a fixed triple? (the verify
> mode you added doesn't actually have to execute the code, right? So you can
> run PPC tests on any platform?)
>
>
>>
>> - Lang.
>>
>> On Sun, Sep 7, 2014 at 9:10 PM, David Blaikie <dblaikie at gmail.com> wrote:
>>
>>>
>>>
>>> On Sat, Sep 6, 2014 at 7:05 PM, Lang Hames <lhames at gmail.com> wrote:
>>>
>>>> Author: lhames
>>>> Date: Sat Sep  6 21:05:26 2014
>>>> New Revision: 217325
>>>>
>>>> URL: http://llvm.org/viewvc/llvm-project?rev=217325&view=rev
>>>> Log:
>>>> [MCJIT] Fix a bug RuntimeDyldImpl's read/writeBytesUnaligned methods.
>>>>
>>>> The previous implementation was writing to the high-bytes of integers
>>>> on BE
>>>> targets (when run on LE hosts).
>>>>
>>>
>>> Not testable? (curious what limitations of your new test infrastructure
>>> (or curiosities of this issue) make it not applicable to testing this bug)
>>>
>>> & any nice way to factor the (admittedly minor) duplication in each of
>>> these codepaths? (could have a function that takes the increment (1 or -1),
>>> non-type template parameter if necessary, but it looks simple/inlinable?)
>>>
>>>
>>>>
>>>> http://llvm.org/PR20640
>>>>
>>>>
>>>> Modified:
>>>>     llvm/trunk/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp
>>>>
>>>> Modified: llvm/trunk/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp
>>>> URL:
>>>> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp?rev=217325&r1=217324&r2=217325&view=diff
>>>>
>>>> ==============================================================================
>>>> --- llvm/trunk/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp
>>>> (original)
>>>> +++ llvm/trunk/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp Sat Sep
>>>> 6 21:05:26 2014
>>>> @@ -398,32 +398,30 @@ unsigned RuntimeDyldImpl::computeSection
>>>>  uint64_t RuntimeDyldImpl::readBytesUnaligned(uint8_t *Src,
>>>>                                               unsigned Size) const {
>>>>    uint64_t Result = 0;
>>>> -  uint8_t *Dst = reinterpret_cast<uint8_t*>(&Result);
>>>> -
>>>> -  if (IsTargetLittleEndian == sys::IsLittleEndianHost) {
>>>> -    if (!sys::IsLittleEndianHost)
>>>> -      Dst += sizeof(Result) - Size;
>>>> -    memcpy(Dst, Src, Size);
>>>> -  } else {
>>>> -    Dst += Size - 1;
>>>> -    for (unsigned i = 0; i < Size; ++i)
>>>> -      *Dst-- = *Src++;
>>>> -  }
>>>> +  if (IsTargetLittleEndian) {
>>>> +    Src += Size - 1;
>>>> +    while (Size--)
>>>> +      Result = (Result << 8) | *Src--;
>>>
>>> +  } else
>>>> +    while (Size--)
>>>> +      Result = (Result << 8) | *Src++;
>>>
>>>
>>>>    return Result;
>>>>  }
>>>>
>>>>  void RuntimeDyldImpl::writeBytesUnaligned(uint64_t Value, uint8_t *Dst,
>>>>                                            unsigned Size) const {
>>>> -  uint8_t *Src = reinterpret_cast<uint8_t*>(&Value);
>>>> -  if (IsTargetLittleEndian == sys::IsLittleEndianHost) {
>>>> -    if (!sys::IsLittleEndianHost)
>>>> -      Src += sizeof(Value) - Size;
>>>> -    memcpy(Dst, Src, Size);
>>>> +  if (IsTargetLittleEndian) {
>>>> +    while (Size--) {
>>>> +      *Dst++ = Value & 0xFF;
>>>> +      Value >>= 8;
>>>> +    }
>>>>    } else {
>>>> -    Src += Size - 1;
>>>> -    for (unsigned i = 0; i < Size; ++i)
>>>> -      *Dst++ = *Src--;
>>>> +    Dst += Size - 1;
>>>> +    while (Size--) {
>>>> +      *Dst-- = Value & 0xFF;
>>>> +      Value >>= 8;
>>>> +    }
>>>>    }
>>>>  }
>>>>
>>>>
>>>>
>>>> _______________________________________________
>>>> llvm-commits mailing list
>>>> llvm-commits at cs.uiuc.edu
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>>>>
>>>
>>>
>>
>
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