SAN FRANCISCO — The six patent cases taken up this term by the U.S. Supreme Court have reform advocates dreaming of a rare opportunity to rein in abusive litigation. And technology companies such as Apple, Google and Yahoo are already lining up to press their cases as amici curiae—though with differing viewpoints about how explicitly to target so-called patent trolls.

Two cases on fee-shifting and another on patent eligibility of computer-related inventions have made the biggest headlines, though some reform advocates say that a previously obscure case in a long-neglected area—indefiniteness—could be the sleeper of the term.