Add lowering support for static_assert

[devalgupta404]

issue #183
Add lowering support for static_assert in the P4HIRToCoreLib conversion.
First I evaluates the assertion condition at compile time. If the condition is a constant boolean true, the call is replaced with p4hir.const #true. If the condition evaluates to false, a diagnostic (static assertion failed) is emitted during lowering.

Covers Four Test cases

• static_assert(true)
• static_assert(true, "message")
• static_assert(false)
• static_assert(false, "message")

I am using '--split-input-file' to run each cases in an independent module otherwise repeated definations of 'static_assert' will cause duplicate symbol errors.

[asl]

This should be done differently. Per spec:

these functions require compile-time known values as arguments, thus they can be used to enforce compile-time invariants

So, the condition could really be resolved later and error out here is a premature.

We'd need to low:

• Lower the generic extern call into a (new) op with clear semantics
• Provide evaluation step (we can just constfold out things with positive assertions, but errors must be done in a separate pass to keep context)

[devalgupta404]

Hi @asl,
I’ve updated the PR to follow the suggested approach.
i Introduced a a new p4corelib.static_assert op with clear semantics, Updated lowering to avoid enforcing compile-time constants during conversion also Implemented a dedicated EvaluateStaticAssertPass and Added folding support in the op for early canonicalization of true cases as well.