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

[Collin Winter]

On Tue, Oct 6, 2009 at 2:01 PM, Jeffrey Yasskin <jyasskin at google.com> wrote:
> On Tue, Oct 6, 2009 at 1:23 PM, Chris Lattner <clattner at apple.com> wrote:
>>
>> 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?
>
> Oops. SmallString<64> it is. Collin, could you check that this still
> works around the gcc-4.0.3 bug?

Still fixes the bug, thanks.

Collin