Commit Graph

5 Commits

Author SHA1 Message Date
Serguei Katkov
164e4fc900 SafepointIRVerifier is made unreachable block tolerant
SafepointIRVerifier crashed while traversing blocks without a DomTreeNode.
This could happen with a custom pipeline or when some optional passes were skipped by OptBisect.

SafepointIRVerifier is fixed to traverse basic blocks that are reachable from entry. Test are added.

Patch Author: Yevgeny Rouban!
Reviewers: anna, reames, dneilson, DaniilSuchkov, skatkov
Reviewed By: reames
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D47011


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@333063 91177308-0d34-0410-b5e6-96231b3b80d8
2018-05-23 05:54:55 +00:00
Max Kazantsev
cbe298eee6 [SafepointIRVerifier] Allow non-dereferencing uses of unrelocated or poisoned PHI nodes
PHI that has at least one unrelocated input cannot cause any issues by itself,
though its uses should be carefully verified. With this patch PHIs are allowed
to have any inputs but when all inputs are unrelocated the PHI is marked as
unrelocated and if not all inputs are unrelocated then the PHI is marked as
poisoned. Poisoned pointers can be used only in three ways: to derive new
pointers, in PHIs or in comparisons against constants that are exclusively
derived from null.

Patch by Daniil Suchkov!

Differential Revision: https://reviews.llvm.org/D41006


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@321438 91177308-0d34-0410-b5e6-96231b3b80d8
2017-12-25 09:35:10 +00:00
Anna Thomas
9f563b480d [SafepointIRVerifier] Allow deriving pointers from unrelocated base
Summary:
This patch allows to use derived pointers (GEPs/bitcasts) of unrelocated
base pointers. We care only about the uses of these derived pointers.

It is acheived by two changes:
1. When we have enough information to say if the pointer is unrelocated at some
point or not, we walk all BBs to remove from their Contributions all valid defs
of unrelocated pointers (GEP with unrelocated base or bitcast of unrelocated
pointer).
2. When it comes to verification we just ignore instructions that were removed
at stage 1.

Patch by Daniil Suchkov!

Reviewers: anna, reames, apilipenko, mkazantsev

Reviewed By: anna, mkazantsev

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D40289

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@319838 91177308-0d34-0410-b5e6-96231b3b80d8
2017-12-05 21:39:37 +00:00
Anna Thomas
25f28db283 [SafepointIRVerifier] Avoid false positives in GC verifier for compare between pointers
Today the safepoint IR verifier catches some unrelocated uses of base
pointers that are actually valid.

With this change, we narrow down the set of false positives.
Specifically, the verifier knows about compares to null and compares
between 2 unrelocated pointers.

Reviewed by: skatkov

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D35057

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@307392 91177308-0d34-0410-b5e6-96231b3b80d8
2017-07-07 13:02:29 +00:00
Anna Thomas
3087bcdef2 [SafepointIRVerifier] Add verifier pass for finding GC relocation bugs
Original Patch and summary by Philip Reames.

RewriteStatepointsForGC tries to rewrite a function in a manner where
the optimizer can't end up using a pointer value after it might have
been relocated by a safepoint. This pass checks the invariant that
RSForGC is supposed to establish and that (if we constructed semantics
correctly) later passes must preserve.

This has been a really useful diagnostic tool when initially developing
the rewriting scheme and has found numerous bugs.

Differential Revision: https://reviews.llvm.org/D15940

Reviewed by: swaroop.sridhar, mjacob

Subscribers: llvm-commits

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@307112 91177308-0d34-0410-b5e6-96231b3b80d8
2017-07-05 01:16:29 +00:00