From 3991b47946784354686aa3275a88458a4ca3d6af Mon Sep 17 00:00:00 2001 From: Philip Reames Date: Mon, 13 Apr 2015 17:35:55 +0000 Subject: [PATCH] [RewriteStatepointsForGC] Strengthen assertions around liveness This is related to the issues addressed in 234651. These assertions check the properties ensured by that change at the place of use. Note that a similiar property is checked in checkBasicSSA, but without the reachability constraint. Technically, the liveness would be correct to include unreachable values, but this would be problematic for actual relocation. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234766 91177308-0d34-0410-b5e6-96231b3b80d8 --- .../Scalar/RewriteStatepointsForGC.cpp | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) diff --git a/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp b/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp index 1f2597c7426..b4752243b6a 100644 --- a/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp +++ b/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp @@ -1879,6 +1879,24 @@ static bool insertParsePoints(Function &F, DominatorTree &DT, Pass *P, Statepoint statepoint(info.StatepointToken); live.insert(live.end(), statepoint.gc_args_begin(), statepoint.gc_args_end()); +#ifndef NDEBUG + // Do some basic sanity checks on our liveness results before performing + // relocation. Relocation can and will turn mistakes in liveness results + // into non-sensical code which is must harder to debug. + // TODO: It would be nice to test consistency as well + assert(DT.isReachableFromEntry(info.StatepointToken->getParent()) && + "statepoint must be reachable or liveness is meaningless"); + for (Value *V : statepoint.gc_args()) { + if (!isa(V)) + // Non-instruction values trivial dominate all possible uses + continue; + auto LiveInst = cast(V); + assert(DT.isReachableFromEntry(LiveInst->getParent()) && + "unreachable values should never be live"); + assert(DT.dominates(LiveInst, info.StatepointToken) && + "basic SSA liveness expectation violated by liveness analysis"); + } +#endif } unique_unsorted(live); -- 2.34.1