<div dir="ltr"><br><div class="gmail_extra"><br><div class="gmail_quote">On Fri, Jan 15, 2016 at 2:56 PM, Benjamin Kramer <span dir="ltr"><<a href="mailto:benny.kra@gmail.com" target="_blank">benny.kra@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><span class="">On Fri, Jan 15, 2016 at 11:52 PM, David Blaikie via cfe-commits<br>
<<a href="mailto:cfe-commits@lists.llvm.org">cfe-commits@lists.llvm.org</a>> wrote:<br>
><br>
><br>
> On Fri, Jan 15, 2016 at 2:29 PM, Joerg Sonnenberger via cfe-commits<br>
> <<a href="mailto:cfe-commits@lists.llvm.org">cfe-commits@lists.llvm.org</a>> wrote:<br>
>><br>
>> Author: joerg<br>
>> Date: Fri Jan 15 16:29:34 2016<br>
>> New Revision: 257947<br>
>><br>
>> URL: <a href="http://llvm.org/viewvc/llvm-project?rev=257947&view=rev" rel="noreferrer" target="_blank">http://llvm.org/viewvc/llvm-project?rev=257947&view=rev</a><br>
>> Log:<br>
>> Avoid self-assignment of SmallString, trigger UB behavior down the road.<br>
><br>
><br>
> Shouldn't we be fixing that in SmallString? (self /move/ assignment arguably<br>
> can be UB, but self copy assign probably shouldn't be)<br>
<br>
</span>It's a partial self-copy via StringRef. I don't think guarding against<br>
that very special case is worth it.<br></blockquote><div><br></div><div>Seems pretty subtle/likely to cause pain in the future, perhaps.<br><br>I assume std::string is resilient to this?<br></div><div> </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div class="HOEnZb"><div class="h5"><br>
>><br>
>><br>
>> Modified:<br>
>>     cfe/trunk/tools/driver/driver.cpp<br>
>><br>
>> Modified: cfe/trunk/tools/driver/driver.cpp<br>
>> URL:<br>
>> <a href="http://llvm.org/viewvc/llvm-project/cfe/trunk/tools/driver/driver.cpp?rev=257947&r1=257946&r2=257947&view=diff" rel="noreferrer" target="_blank">http://llvm.org/viewvc/llvm-project/cfe/trunk/tools/driver/driver.cpp?rev=257947&r1=257946&r2=257947&view=diff</a><br>
>><br>
>> ==============================================================================<br>
>> --- cfe/trunk/tools/driver/driver.cpp (original)<br>
>> +++ cfe/trunk/tools/driver/driver.cpp Fri Jan 15 16:29:34 2016<br>
>> @@ -290,9 +290,9 @@ static void SetInstallDir(SmallVectorImp<br>
>>    if (CanonicalPrefixes)<br>
>>      llvm::sys::fs::make_absolute(InstalledPath);<br>
>><br>
>> -  InstalledPath = llvm::sys::path::parent_path(InstalledPath);<br>
>> -  if (llvm::sys::fs::exists(InstalledPath.c_str()))<br>
>> -    TheDriver.setInstalledDir(InstalledPath);<br>
>> +  StringRef<br>
>> InstalledPathParent(llvm::sys::path::parent_path(InstalledPath));<br>
>> +  if (llvm::sys::fs::exists(InstalledPathParent))<br>
>> +    TheDriver.setInstalledDir(InstalledPathParent);<br>
>>  }<br>
>><br>
>>  static int ExecuteCC1Tool(ArrayRef<const char *> argv, StringRef Tool) {<br>
>><br>
>><br>
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><br>
><br>
><br>
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</div></div></blockquote></div><br></div></div>