tree d8e9ddbe3fa626067f2409793383c48f4969aa1c
parent f590845f5017bf0f131bb05b5ee51cfb7756aec2
author Jorge Gorbe Moya <jgorbe@google.com> 1605812348 -0800
committer Tom Stellard <tstellar@redhat.com> 1606373041 -0500

Fix crash after looking up dwo_id=0 in CU index.

In the current state, if getFromHash(0) is called and there's no CU with
dwo_id=0, the lookup will stop at an empty slot, then the check
`Rows[H].getSignature() != S` won't cause the lookup to fail and return
a nullptr (as it should), because the empty slot has a 0 in the
signature field, and a pointer to the empty slot will be incorrectly
returned.

This patch fixes this by using the index field in the hash entry to
check for empty slots: signature = 0 can match a valid hash but
according to the spec the index for an occupied slot will always be
non-zero.

Differential Revision: https://reviews.llvm.org/D91670

(cherry picked from commit 314a0d73a8444e3b0c1a0d0de7d615d9448af1c9)