[cfe-commits] [PATCH] A tentative implementation of RegionStoreManager

[Ted Kremenek]

On Oct 5, 2008, at 6:28 PM, Zhongxing Xu wrote:

> My either idea was to have regions encode minimal information that  
> could be shared amongst different implementations of StoreManager.   
> I'm not really certain why you wish to add a VarDecl* "pointedBy"  
> field into AnonTypedRegion?  I didn't get around to commenting this  
> class, but AnonTypedRegion is meant to represent a typed chunk of  
> memory; it doesn't have to be pointed by a VarDecl.   It also seems  
> to me that you are using AnonTypedRegion exactly the way BasicStore  
> uses VarRegion.  Isn't it the same thing?  The "Anon" means  
> anonymous; it means there is no name associated with this region.
>
> I use VarDecl* to differentiate AnonTypedRegions. For example, for
>
> void foo(char* a, char* b) {...},
>
> 'a' and 'b' both points to an AnonTypedRegion with type 'char', I  
> just use the VarDecl's of 'a' and 'b' to differentiate these two  
> regions. This is definitely not optimal design, because there might  
> be AnonTypedRegion that are not pointed to by any variable. So it  
> should be discussed. But one thing is sure: we need something to be  
> associated with AnonTypedRegion besides its type and superregion.

I understand, but this particular use of AnonTypedRegions is exactly  
the same as VarRegion.  Why not just use VarRegion instead and save  
the extra QualType?  It also avoids putting the VarDecl* in  
AnonTypedRegion, since at that point the region is not anonymous.

It seems to me that RegionStoreManager doesn't need to use just one  
kind of region and one ImmutableMap.  For example, a map from VarDecl*  
-> VarRegion could be used for mappings from variables to regions, and  
then other maps could be used for other bindings.  For example, a  
(MemRegion*, FieldDecl*) -> FieldRegion could be used for field  
bindings.  A second set of mappings could then be used for region ->  
value bindings.  In your prototype implementation you have  
AnonTypedRegion* -> RVal, but one could also just have MemRegion* ->  
RVal.
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