Simon Marlow authored Oct 30, 2015 and Ben Gamari committed Oct 30, 2015

It was possible to read non-existent memory, if we try to read the
srt_offset field of an info table when there is no SRT, and the info
table is right at the start of the text section.

This actually happened to me, I'm not sure why it never happened
before.

Test Plan: validate

Reviewers: rwbarton, ezyang, austin, bgamari

Reviewed By: austin, bgamari

Subscribers: thomie

Differential Revision: https://phabricator.haskell.org/D1401