[cfe-commits] [PATCH] Fix for PR7218, and analyzer support for calloc()

[Jordy Rose]

Fixes PR7218 "Assigning to buf[0] makes buf[1] valid" by not allowing
arrays and symbolic regions to have direct bindings, only bindings to
element 0. (The exception is symbolic regions for references, since they
don't have elements.)

On top of that, adds support for calloc(), treating its result as a
malloc-region that needs freeing, whose contents are initialized to 0.

I'm not entirely happy with the replacement of *p with p[0] in
GRExprEngine, but that seems to be the last place where you can tell the
difference between a binding to p and a binding to p[0].

This could be split into two patches, of course, though I worked on it all
simultaneously. The calloc() part requires a way to set default elements
for regions -- I did it by using the assumption that arrays and symbolic
regions couldn't get direct bindings, only default ones, but it could also
be done by adding another method to Store (really RegionStore).

Jordy