[PATCH] D136162: [analyzer] Fix assertion failure in RegionStore within bindArray()

Wed Oct 19 04:37:14 PDT 2022

steakhal added a comment.

In D136162#3865081 <https://reviews.llvm.org/D136162#3865081>, @martong wrote:

> Hmm, seems like the conflicting prototype (i.e. the obsolescent use of zero parameters) is needed to reproduce the assertion failure. That makes me wonder, how does the redecl chain of `b` looks like? Is `void b()` chained with `void b(int*)`, or are they represented independently from each other? I guess they form the same redecl chain. Which drives us to the next questions.
> When the analyzer reaches the CallExpr `b(&buffer)` which FunctionDecl does it see? Is it `b()` or `b(int*)`? My bet, it sees and works with `b()`.

Yes, they form the same redecl chain, indeed.
The call `b(&buffer)` refers to the `void ()` decl - with no parameters.
The range of `->redecls()` of that decl has two items:
The decl of `void ()`, and the decl of `void (int *)`.

> Could we detect if the arguments of the CallExpr does not match the parameters of the FunctionDecl? And if that is the case, could we iterate through the redecl chain to find an appropriate matching FunctionDecl? That would be `b(int*)` in this case ... and the original `bindArray()` should work then.

Good idea. Actually, the CFG already refers to the `void ()` delc, so we should probably change it there instead of doing the same in the CSA.
Let me investigate this route.

In D136162#3865094 <https://reviews.llvm.org/D136162#3865094>, @martong wrote:

>> A similar situation could happen if we reinterpret cast pointers, etc. so the situation is not limited to conflicting function prototypes.
>
> Please provide tests for those cases.

It was a harsh guess on my part, simply by looking at the missing `ElementRegion`, I thought that I could reconstruct the example by some reinterpret-cast tricks - but I could not pull it off.
Disregard that part.

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https://reviews.llvm.org/D136162