public int getInstructionLength(PatternExpression exp) {
		return getRegistered(exp.getClass()).getInstructionLength(exp);
	}
Determine the length of the instruction part of the encoded solution to the given expression

<p>
This is used to keep operands in their appropriate position when backfilling becomes
applicable. Normally, the instruction length is taken from the encoding of a solution, but if
the solution cannot be determined yet, the instruction length must still be obtained.

<p>
The length can be determined by finding token fields in the expression.

@param exp the expression, presumably containing a token field
@return the anticipated length, in bytes, of the instruction encoding
Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/app/plugin/assembler/sleigh/expr/RecursiveDescentSolver.java