[llvm] r336837 - [DebugInfo] Fix getPreviousSibling after r336823

[Fangrui Song via llvm-commits]

On 2018-07-11, Vedant Kumar wrote:
>In the future if you could describe what exactly you are fixing in your commit message, it would help readers like me understand what's going on.
>
>thanks!
>vedant

Sorry, it was to fix the dead loop (an unsigned integer is always >= 0)
but I'm not sure if it could be triggered. I'll be mindful. Thanks!

>
>> On Jul 11, 2018, at 5:34 PM, Vedant Kumar <vsk at apple.com> wrote:
>>
>> Hi Fangrui,
>>
>> If the Die has a non-zero depth, isn't it guaranteed to have a non-zero index? If this really needs to be clearer, why not assert that the index is non-zero?
>>
>> vedant
>>
>>
>>> On Jul 11, 2018, at 12:09 PM, Fangrui Song via llvm-commits <llvm-commits at lists.llvm.org> wrote:
>>>
>>> Author: maskray
>>> Date: Wed Jul 11 12:09:37 2018
>>> New Revision: 336837
>>>
>>> URL: http://llvm.org/viewvc/llvm-project?rev=336837&view=rev
>>> Log:
>>> [DebugInfo] Fix getPreviousSibling after r336823
>>>
>>> Modified:
>>>   llvm/trunk/lib/DebugInfo/DWARF/DWARFUnit.cpp
>>>
>>> Modified: llvm/trunk/lib/DebugInfo/DWARF/DWARFUnit.cpp
>>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/DebugInfo/DWARF/DWARFUnit.cpp?rev=336837&r1=336836&r2=336837&view=diff
>>> ==============================================================================
>>> --- llvm/trunk/lib/DebugInfo/DWARF/DWARFUnit.cpp (original)
>>> +++ llvm/trunk/lib/DebugInfo/DWARF/DWARFUnit.cpp Wed Jul 11 12:09:37 2018
>>> @@ -593,7 +593,8 @@ DWARFDie DWARFUnit::getPreviousSibling(c
>>>    return DWARFDie();
>>>
>>>  // Find the previous DIE whose depth is the same as the Die's depth.
>>> -  for (size_t I = getDIEIndex(Die) - 1; I >= 0; --I) {
>>> +  for (size_t I = getDIEIndex(Die); I > 0;) {
>>> +    --I;
>>>    if (DieArray[I].getDepth() == Depth - 1)
>>>      return DWARFDie();
>>>    if (DieArray[I].getDepth() == Depth)
>>>
>>>
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>>
>

-- 
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