public RegisterSpec findMatchingLocal(RegisterSpec spec) {
    int length = specs.length;

    for (int reg = 0; reg < length; reg++) {
      RegisterSpec s = specs[reg];

      if (s == null) {
        continue;
      }

      if (spec.matchesVariable(s)) {
        return s;
      }
    }

    return null;
  }
Returns the spec in this set that's currently associated with a given local (type, name, and
signature), or {@code null} if there is none. This ignores the register number of the given
spec but matches on everything else.

@param spec {@code non-null;} local to look for
@return {@code null-ok;} first register found that matches, if any
android/android_framework/dex-maker/src/main/java/com/android/dx/rop/code/RegisterSpecSet.java