[llvm-commits] [llvm] r165038 - /llvm/trunk/lib/Support/StringRef.cpp

[David Blaikie]

On Wed, Oct 3, 2012 at 11:21 AM, Nick Kledzik <kledzik at apple.com> wrote:
>
> On Oct 2, 2012, at 11:45 PM, David Blaikie wrote:
>
>> On Tue, Oct 2, 2012 at 1:01 PM, Nick Kledzik <kledzik at apple.com> wrote:
>>> Author: kledzik
>>> Date: Tue Oct  2 15:01:48 2012
>>> New Revision: 165038
>>>
>>> URL: http://llvm.org/viewvc/llvm-project?rev=165038&view=rev
>>> Log:
>>> Improve overflow detection in StringRef::getAsUnsignedInteger().
>>
>> Are there existing unit tests you could update to validate this change?
> Good point.  I looked over the existing test cases and they just check that valid strings are properly parsed.
> So I added a test case which passes a list of malformed strings to getAsUnsignedInteger() and
> verifies that they are rejected.  I also verified that the new test case passes with my previous commit
> and fails without it.
>
> Committed revision 165136.

Looks great - thanks!

>
> -Nick
>
>
>>
>>>
>>> Modified:
>>>    llvm/trunk/lib/Support/StringRef.cpp
>>>
>>> Modified: llvm/trunk/lib/Support/StringRef.cpp
>>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Support/StringRef.cpp?rev=165038&r1=165037&r2=165038&view=diff
>>> ==============================================================================
>>> --- llvm/trunk/lib/Support/StringRef.cpp (original)
>>> +++ llvm/trunk/lib/Support/StringRef.cpp Tue Oct  2 15:01:48 2012
>>> @@ -350,8 +350,8 @@
>>>     unsigned long long PrevResult = Result;
>>>     Result = Result*Radix+CharVal;
>>>
>>> -    // Check for overflow.
>>> -    if (Result < PrevResult)
>>> +    // Check for overflow by shifting back and seeing if bits were lost.
>>> +    if (Result/Radix < PrevResult)
>>>       return true;
>>>
>>>     Str = Str.substr(1);
>>>
>>>
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>