[Bf-committers] PVS-Studio Static Analysis

[Jason Wilkins]

This line in btQuantizedBvh.h confuses me:

int	getTriangleIndex() const
	{
		btAssert(isLeafNode());
		unsigned int x=0;
		unsigned int y = (~(x&0))<<(31-MAX_NUM_PARTS_IN_BITS);
		// Get only the lower bits where the triangle index is stored
		return (m_escapeIndexOrTriangleIndex&~(y));
	}

Ostensibly the error is that ~0 is -1 (unsigned) and shifting an
unsigned is undefined or unspecified (forget which).

But I'm actually confused why this code is written this way.
x=0, then x&0 == 0, even if x wasn't 0.

Only after that do we get to the undefined behavior.

I guess I could puzzle through it, but somebody else might just know :-)

On Tue, Apr 24, 2012 at 7:30 PM, Jason Wilkins
<jason.a.wilkins at gmail.com> wrote:
> I'm working through them and fixing what Clang did not catch.
>
> I was going to say the same thing as Nicholas, code analysis is such a
> wide open field with virtually infinite number of things you can check
> for, that having more than one tool is a good idea.
>
> On Tue, Apr 24, 2012 at 6:30 PM, Nicholas Bishop
> <nicholasbishop at gmail.com> wrote:
>> Not necessarily; different static analyzers can detect different types
>> of potential problems. The PVS analysis contains some interesting
>> things like the "Misprint in a homogeneous code block" section that I
>> don't think clang's analyzer does.
>>
>> On Tue, Apr 24, 2012 at 7:20 PM, Tom M <letterrip at gmail.com> wrote:
>>> We have a page with generated CLang static analysis,
>>>
>>> http://clang.blenderheads.org/trunk/
>>>
>>> It probably shows the same bugs as PVS-Studio does.
>>>
>>> LetterRip
>>>
>>> On Tue, Apr 24, 2012 at 4:15 PM, Nicholas Bishop
>>> <nicholasbishop at gmail.com> wrote:
>>>> I think some of these have been fixed already in recent commits from Campbell.
>>>>
>>>> On Tue, Apr 24, 2012 at 7:11 PM, Jason Wilkins
>>>> <jason.a.wilkins at gmail.com> wrote:
>>>>> http://www.viva64.com/en/b/0145/#ID0EO3BK
>>>>>
>>>>> It appears that Andrey Karpov has done an analysis of Blender source
>>>>> code using his PVS-Studio tool.  He did this just yesterday, so I
>>>>> assume the problems he found are still in the source.  He offers free
>>>>> licenses to open source project members (3500 euro software otherwise,
>>>>> wow).
>>>>>
>>>>> I was thinking of investigating the problems he found and seeing if I
>>>>> could fix them.
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