Diablo Cody’s script about a runaway rocker mother who attempts to reconnect with her family feels prescriptive, but the cast’s performances are so good that it doesn’t matterIt takes just five seconds to realise that this will be a memorable movie. There’s the opening jangly chords to Tom Petty and the Heartbreaker’s American Girl, and then in close-up, Meryl Streep with ratty braids, bad makeup and a bold, deep, rockin’ voice.