[llvm] r244455 - Modify r244405 to clearer code, per David Blaikie suggestion.

[Frédéric Riss via llvm-commits]

> On Aug 10, 2015, at 9:46 AM, David Blaikie via llvm-commits <llvm-commits at lists.llvm.org> wrote:
> 
> 
> 
> On Mon, Aug 10, 2015 at 9:15 AM, Yaron Keren via llvm-commits <llvm-commits at lists.llvm.org <mailto:llvm-commits at lists.llvm.org>> wrote:
> Author: yrnkrn
> Date: Mon Aug 10 11:15:51 2015
> New Revision: 244455
> 
> URL: http://llvm.org/viewvc/llvm-project?rev=244455&view=rev <http://llvm.org/viewvc/llvm-project?rev=244455&view=rev>
> Log:
> Modify r244405 to clearer code, per David Blaikie suggestion.
> 
> 
> Modified:
>     llvm/trunk/tools/dsymutil/DwarfLinker.cpp
> 
> Modified: llvm/trunk/tools/dsymutil/DwarfLinker.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/tools/dsymutil/DwarfLinker.cpp?rev=244455&r1=244454&r2=244455&view=diff <http://llvm.org/viewvc/llvm-project/llvm/trunk/tools/dsymutil/DwarfLinker.cpp?rev=244455&r1=244454&r2=244455&view=diff>
> ==============================================================================
> --- llvm/trunk/tools/dsymutil/DwarfLinker.cpp (original)
> +++ llvm/trunk/tools/dsymutil/DwarfLinker.cpp Mon Aug 10 11:15:51 2015
> @@ -2884,8 +2884,8 @@ void DwarfLinker::patchLineTableForUnit(
>        if (StopAddress != -1ULL && !Seq.empty()) {
>          // Insert end sequence row with the computed end address, but
>          // the same line as the previous one.
> -        Seq.reserve(Seq.size() + 1);
> -        Seq.emplace_back(Seq.back());
> +        auto NextLine = Seq.back();
> +        Seq.emplace_back(NextLine);
> 
> I don't think there's any benefit to emplace_back here since there are no explicit conversions required. I'd probably usse push_back - and this still seems like it'd be easy for someone to just decide to fold the two statements together & create the original bug. The suggestion I was making was to avoid doing the initialization (the following several assignment statements \/ ) on the container element itself, but do it on the local. Then push that local onto the sequence - that seems less subtle (or at least it hides it better by not making it look like a trivial cleanup to collapse two expressions would be an improvement).

FWIW, I agree with David here.

>          Seq.back().Address = StopAddress;
>          Seq.back().EndSequence = 1;
>          Seq.back().PrologueEnd = 0;
> 
> 
> _______________________________________________
> llvm-commits mailing list
> llvm-commits at lists.llvm.org <mailto:llvm-commits at lists.llvm.org>
> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-commits <http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-commits>
> 
> _______________________________________________
> llvm-commits mailing list
> llvm-commits at lists.llvm.org
> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-commits

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20150810/77c84fe3/attachment.html>