Commit 8e9cef2e6f5156c4b055a04a8f979b7291fc6b7a
2015-09-21T12:57:41
Fix various issues reported by the UB sanitizers Most of these involved left shifting a negative number, which is technically undefined (although every modern compiler I'm aware of will implement this by treating the signed integer as a 2's complement unsigned integer-- the LEFT_SHIFT() macro just makes this behavior explicit in order to shut up ubsan.) This also fixes a couple of non-issues in the entropy codecs, whereby the sanitizer reported an out-of-bounds index in the 4th argument of jpeg_make_d_derived_tbl(). In those cases, the index was actually out of bounds (caused by a malformed JPEG image), but jpeg_make_d_derived_tbl() would have caught the error and aborted prior to actually using the invalid address. Here again, the fix was to make our intentions explicit so as to shut up ubsan.