[cfe-dev] Where are the methods, which handle the Element Region’s index, in Clang Static Analyzer?

[Jordan Rose]

That's correct. Also, remember that symbolic values are immutable; when you do "ptr = ptr + 3", you're storing a new value into the same location. So the ElementRegion's index doesn't change, but 'ptr' now refers to a different ElementRegion.

Jordan


On Nov 4, 2013, at 4:33 , Arthur Yoo <phjy007 at gmail.com> wrote:

> It seems that evalBinOp() will do the related things. evalBinOp() also calls evalBinOpLN() and evalBinOpNN().
> 
> 
> 2013/10/30 Arthur Yoo <phjy007 at gmail.com>
> Hi all,
> 
> 
> 
> ElementRegion has a field named Index (NoLoc) to record the index of that Array Element. We can also use pointer offset operation to calculate a new index and get the corresponding array element. For example:
> 
> 1 void func() {
> 
> 2    int arr[10];
> 
> 3     int *ptr, *ptr2;
> 
> 4     ptr = arr;
> 
> 5     ptr = ptr + 3;
> 
> 6     *ptr = 9;
> 
> 7     ptr2 = ptr + 1;
> 
> 8     *ptr2 = 10;
> 
> 9 }
> 
> 
> 
> Line 5 shows the pointer offset operation. I dumped the information of the pointee MemRegion referenced by ptr, the Static Analyzer gave me such result: element{arr,3 S32b,int}. That means after the pointer offset operation by line 5, the ptr’s pointee MemRegion became an ElementRegion of arr[], which index was 3 S32b. The line 7’s effect is same, it showed me element{arr,4 S32b,int}. Obviously, after the pointer offset operation, the ElementRegion’s Index will be changed. I want to know where are the methods that handle the Element Region’s index in pointer offset operation. Cause I want to find these methods and add some codes into them. 
> 
> Thanks a lot.
> 
> 
> -- 
> Best regards,
> Arthur Yoo
> 
> 
> 
> -- 
> Best regards,
> 岳佳圆 | Yue Jiayuan | Arthur Yoo
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