[cfe-commits] r59957 - in /cfe/trunk: include/clang/Analysis/PathSensitive/Store.h lib/Analysis/GRExprEngine.cpp lib/Analysis/RegionStore.cpp

[Ted Kremenek]

On Nov 24, 2008, at 4:17 PM, Zhongxing Xu wrote:

> On Tue, Nov 25, 2008 at 3:03 AM, Ted Kremenek <kremenek at apple.com>  
> wrote:
> Hi Zhongxing,
>
> Why use the GDM to represent the byte extent of an AllocaRegion  
> instead of storing it directly in the region object itself?  I don't  
> think it's necessarily a bad idea; I'm just curious about the  
> overall design.
>
> I don't have a definite reason for this. I feel that:
>
> - The extent is not a necessary property of AllocaRegion (or the  
> necessity has not showed). If we make it part of the AllocaRegion,  
> that would require all clients provide an extent when creating the  
> AllocaRegion.

Just to clarify, what do you mean by "clients?"  Different  
implementations of StoreManager?

> - Decoupling the extent of the dynamically allocated region provides  
> more flexibility. Consider a MallocRegion, whose extent may be  
> changed by a later realloc(). But its store bindings may not change.  
> In that case, we can only modify the extent mapping of it.

Makes sense.

> - If later we find the extent is an essential property of  
> AllocaRegion, we can add it back.

Absolutely.  I wasn't arguing that we change it.  All of this sounds  
good to me.

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