P4::CastBooleanTableKeys Class Reference

Inheritance diagram for P4::CastBooleanTableKeys:

Public Member Functions
const IR::Node *	postorder (IR::Entry *entry) override
const IR::Node *	postorder (IR::KeyElement *key) override

Detailed Description

Adds a bit<1> cast to all boolean keys. This is because these keys need to be converted into bit expressions for the control plane. Also replaces all the corresponding entries in the table with the appropriate expression. Example:

   table t {
     key = { h.a  : exact; }
     const entries = {
            true : action();
+        }
   }
   apply {
     t.apply();
   }

is transformed to

   table t {
     key = { (bit<1>) h.a  : exact; }
     const entries = {
            1w1 : action();
+        }
   }
   apply {
     t.apply();
   }

Precondition

none

Postcondition

all boolean table key expressions are replaced with a bit<1> cast. Constant entries are replaced with 1w1 (true) or 1w0 (false).