[llvm-commits] [llvm] r83391 - /llvm/trunk/lib/Support/Triple.cpp

[Chris Lattner]

On Oct 6, 2009, at 10:25 AM, Jeffrey Yasskin wrote:

> Author: jyasskin
> Date: Tue Oct  6 12:25:50 2009
> New Revision: 83391
>
> URL: http://llvm.org/viewvc/llvm-project?rev=83391&view=rev
> Log:
> Fix PR5112, a miscompilation on gcc-4.0.3.  Patch by Collin Winter!
>
> Modified:
>    llvm/trunk/lib/Support/Triple.cpp
>
> Modified: llvm/trunk/lib/Support/Triple.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Support/Triple.cpp?rev=83391&r1=83390&r2=83391&view=diff
>
> =
> =
> =
> =
> =
> =
> =
> =
> ======================================================================
> --- llvm/trunk/lib/Support/Triple.cpp (original)
> +++ llvm/trunk/lib/Support/Triple.cpp Tue Oct  6 12:25:50 2009
> @@ -390,7 +390,10 @@
> }
>
> void Triple::setArchName(const StringRef &Str) {
> -  setTriple(Str + "-" + getVendorName() + "-" +  
> getOSAndEnvironmentName());
> +  // Work around a miscompilation bug in gcc 4.0.3.
> +  Twine a = getVendorName() + "-" + getOSAndEnvironmentName();
> +  Twine b = Str + "-" + a;
> +  setTriple(b);
> }

Jeffrey, I don't think this patch is safe.  Twines are constructed  
based on temporaries.  I think taht the temporary returned by  
getVendorName() is destroyed at the ";" and the twine refers to the  
dangling pointer.  CAn you just build up a temporary std::string  
instead?

-Chris