r253410 - Fix for use-after-free which caused test failure in cuda-detect.cu.

[Artem Belevich via cfe-commits]

getLibDeviceFile only used once per device-side compilation in driver, so
returning the string should be OK here.

BTW, would copy elision kick in when I use std::string Path =
getLibDeviceFile("foo"); ?

--Artem

On Tue, Nov 17, 2015 at 5:12 PM, David Blaikie <dblaikie at gmail.com> wrote:

>
>
> On Tue, Nov 17, 2015 at 4:37 PM, Artem Belevich via cfe-commits <
> cfe-commits at lists.llvm.org> wrote:
>
>> Author: tra
>> Date: Tue Nov 17 18:37:41 2015
>> New Revision: 253410
>>
>> URL: http://llvm.org/viewvc/llvm-project?rev=253410&view=rev
>> Log:
>> Fix for use-after-free which caused test failure in cuda-detect.cu.
>>
>> Return std::string itself instead StringRef to a temporary std::string.
>>
>> Modified:
>>     cfe/trunk/lib/Driver/ToolChains.h
>>
>> Modified: cfe/trunk/lib/Driver/ToolChains.h
>> URL:
>> http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Driver/ToolChains.h?rev=253410&r1=253409&r2=253410&view=diff
>>
>> ==============================================================================
>> --- cfe/trunk/lib/Driver/ToolChains.h (original)
>> +++ cfe/trunk/lib/Driver/ToolChains.h Tue Nov 17 18:37:41 2015
>> @@ -186,7 +186,7 @@ protected:
>>      /// \brief Get the detected Cuda device library path.
>>      StringRef getLibDevicePath() const { return CudaLibDevicePath; }
>>      /// \brief Get libdevice file for given architecture
>> -    StringRef getLibDeviceFile(StringRef Gpu) const {
>> +    std::string getLibDeviceFile(StringRef Gpu) const {
>>        return CudaLibDeviceMap.lookup(Gpu);
>>
>
> You could implement this as:
>
> auto I = CudaLibDeviceMap.find(Gpu);
> return I != CudaLibDeviceMap.end() ? I->second : "";
>
> returning StringRef
>
> Or, if you know the element will always be in the collection, you could
> just assert that and "return CudaLibDeviceMap[Gpu]; - and you could return
> const std::string& there, or StringRef, whichever.
>
> (both/any of these options would avoid needing to allocate a new string to
> every caller)
>
>
>>      }
>>    };
>>
>>
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>>
>
>


-- 
--Artem Belevich
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