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Oddexpr-check

Vl-expr-probable-selfsize

Heuristically estimate an expression's size.

Signature
(vl-expr-probable-selfsize x ss) → size
Arguments: x — Guard (vl-expr-p x).; ss — Guard (vl-scopestack-p ss).
Returns: size — The probable size of this expression, or nil for failure.
Type (maybe-natp size).

There's no reason to believe the size it returns will be the eventual size of the expression because size propagation hasn't been taken into account; in fact we may just fail and return nil for a number of reasons (for instance the wire ranges may not be resolved yet), there's no way to get the failure reason.

On the other hand, I think it should be the case that the final size of the expression will always be at least as much as this selfsize, if it returns a non-nil value. And we can use this before resolving ranges, etc., which makes it useful for simple linting.

Definitions and Theorems

Function: vl-expr-probable-selfsize

(defun vl-expr-probable-selfsize (x ss)
  (declare (xargs :guard (and (vl-expr-p x)
                              (vl-scopestack-p ss))))
  (let ((__function__ 'vl-expr-probable-selfsize))
    (declare (ignorable __function__))
    (b* (((mv & size)
          (vl-expr-selfsize x ss (vl-elabscopes-init-ss ss))))
      size)))

Theorem: maybe-natp-of-vl-expr-probable-selfsize

(defthm maybe-natp-of-vl-expr-probable-selfsize
  (b* ((size (vl-expr-probable-selfsize x ss)))
    (maybe-natp size))
  :rule-classes :type-prescription)

Theorem: vl-expr-probable-selfsize-of-vl-expr-fix-x

(defthm vl-expr-probable-selfsize-of-vl-expr-fix-x
  (equal (vl-expr-probable-selfsize (vl-expr-fix x)
                                    ss)
         (vl-expr-probable-selfsize x ss)))

Theorem: vl-expr-probable-selfsize-vl-expr-equiv-congruence-on-x

(defthm vl-expr-probable-selfsize-vl-expr-equiv-congruence-on-x
  (implies (vl-expr-equiv x x-equiv)
           (equal (vl-expr-probable-selfsize x ss)
                  (vl-expr-probable-selfsize x-equiv ss)))
  :rule-classes :congruence)

Theorem: vl-expr-probable-selfsize-of-vl-scopestack-fix-ss

(defthm vl-expr-probable-selfsize-of-vl-scopestack-fix-ss
  (equal (vl-expr-probable-selfsize x (vl-scopestack-fix ss))
         (vl-expr-probable-selfsize x ss)))

Theorem: vl-expr-probable-selfsize-vl-scopestack-equiv-congruence-on-ss

(defthm
     vl-expr-probable-selfsize-vl-scopestack-equiv-congruence-on-ss
  (implies (vl-scopestack-equiv ss ss-equiv)
           (equal (vl-expr-probable-selfsize x ss)
                  (vl-expr-probable-selfsize x ss-equiv)))
  :rule-classes :congruence)