[llvm] r314801 - [Dominators] Add DFS number verification

Juergen Ributzka via llvm-commits llvm-commits at lists.llvm.org
Tue Oct 3 17:07:00 PDT 2017


Yup, that fixed it. Thanks Jakub

On Tue, Oct 3, 2017 at 2:27 PM, Jakub (Kuba) Kuderski <
kubakuderski at gmail.com> wrote:

> I submitted the fix for DT::eraseNode issue in r314847.
>
> On Tue, Oct 3, 2017 at 4:46 PM, Jakub (Kuba) Kuderski <
> kubakuderski at gmail.com> wrote:
>
>> Well, I don't know why it's failing by just looking at it. I'll submit a
>> fix for the LoopRotate bug in a moment and will see it unbreaks this
>> buildbot.
>>
>> On Tue, Oct 3, 2017 at 4:42 PM, Juergen Ributzka <juergen at ributzka.de>
>> wrote:
>>
>>> I don't know if this is reproducible on Linux, but the file that is
>>> failing is common code in compiler-rt (sanitizer_libc.cc.o).
>>>
>>> On Tue, Oct 3, 2017 at 1:32 PM, Jakub (Kuba) Kuderski <
>>> kubakuderski at gmail.com> wrote:
>>>
>>>> Hi Juergen,
>>>>
>>>> It seems like the patch caught some invalid DominatorTrees :).
>>>>
>>>> I'm now investigating a failure in LoopRotation happening in
>>>> test/Transforms/ArgumentPromotion/pr3085.ll with expensive checks
>>>> enabled, but I don't know if that's related.
>>>> I looked and the buildbot's output and it seems to fail on OSX -- do
>>>> you know if it's reproducible on x86_64 linux?
>>>>
>>>> Best,
>>>> Jakub
>>>>
>>>> On Tue, Oct 3, 2017 at 4:26 PM, Juergen Ributzka <juergen at ributzka.de>
>>>> wrote:
>>>>
>>>>> Hi Jakub,
>>>>>
>>>>> I think this broke one of our jobs on Green Dragon:
>>>>> http://green.lab.llvm.org/green/job/clang-stage1-cmake-RA-ex
>>>>> pensive/8568/consoleFull
>>>>>
>>>>> Could you please take a look?
>>>>>
>>>>> Thanks
>>>>>
>>>>> Cheers,
>>>>> Juergen
>>>>>
>>>>> On Tue, Oct 3, 2017 at 7:33 AM, Jakub Kuderski via llvm-commits <
>>>>> llvm-commits at lists.llvm.org> wrote:
>>>>>
>>>>>> Author: kuhar
>>>>>> Date: Tue Oct  3 07:33:41 2017
>>>>>> New Revision: 314801
>>>>>>
>>>>>> URL: http://llvm.org/viewvc/llvm-project?rev=314801&view=rev
>>>>>> Log:
>>>>>> [Dominators] Add DFS number verification
>>>>>>
>>>>>> Summary:
>>>>>> This patch teaches the DominatorTree verifier to check DFS In/Out
>>>>>> numbers which are used to answer dominance queries.
>>>>>> DFS number verification is done in O(nlogn), so it shouldn't add much
>>>>>> overhead on top of the O(n^3) sibling property verification.
>>>>>> This check should detect errors like the one spotted in PR34466 and
>>>>>> related bug reports.
>>>>>>
>>>>>> The patch also cleans up the DFS calculation a bit, as all
>>>>>> constructed trees should have a single root now.
>>>>>>
>>>>>> I see 2 new test failures when running check-all after this change:
>>>>>>
>>>>>> ```
>>>>>> Failing Tests (2):
>>>>>>     Polly :: Isl/CodeGen/OpenMP/reference-a
>>>>>> rgument-from-non-affine-region.ll
>>>>>>     Polly :: Isl/CodeGen/OpenMP/two-paralle
>>>>>> l-loops-reference-outer-indvar.ll
>>>>>>
>>>>>> ```
>>>>>> which seem to happen just after `Create LLVM-IR from SCoPs` -- I
>>>>>> XFAILed them in r314800.
>>>>>>
>>>>>> Reviewers: dberlin, grosser, davide, zhendongsu, bollu
>>>>>>
>>>>>> Reviewed By: dberlin
>>>>>>
>>>>>> Subscribers: nandini12396, bollu, Meinersbur, brzycki, llvm-commits
>>>>>>
>>>>>> Differential Revision: https://reviews.llvm.org/D38331
>>>>>>
>>>>>> Modified:
>>>>>>     llvm/trunk/include/llvm/Support/GenericDomTree.h
>>>>>>     llvm/trunk/include/llvm/Support/GenericDomTreeConstruction.h
>>>>>>
>>>>>> Modified: llvm/trunk/include/llvm/Support/GenericDomTree.h
>>>>>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/
>>>>>> Support/GenericDomTree.h?rev=314801&r1=314800&r2=314801&view=diff
>>>>>> ============================================================
>>>>>> ==================
>>>>>> --- llvm/trunk/include/llvm/Support/GenericDomTree.h (original)
>>>>>> +++ llvm/trunk/include/llvm/Support/GenericDomTree.h Tue Oct  3
>>>>>> 07:33:41 2017
>>>>>> @@ -702,28 +702,25 @@ public:
>>>>>>        return;
>>>>>>      }
>>>>>>
>>>>>> -    unsigned DFSNum = 0;
>>>>>> -
>>>>>>      SmallVector<std::pair<const DomTreeNodeBase<NodeT> *,
>>>>>>                            typename DomTreeNodeBase<NodeT>::const_
>>>>>> iterator>,
>>>>>>                  32> WorkStack;
>>>>>>
>>>>>>      const DomTreeNodeBase<NodeT> *ThisRoot = getRootNode();
>>>>>> -
>>>>>> +    assert((!Parent || ThisRoot) && "Empty constructed DomTree");
>>>>>>      if (!ThisRoot)
>>>>>>        return;
>>>>>>
>>>>>> -    // Even in the case of multiple exits that form the post
>>>>>> dominator root
>>>>>> -    // nodes, do not iterate over all exits, but start from the
>>>>>> virtual root
>>>>>> -    // node. Otherwise bbs, that are not post dominated by any exit
>>>>>> but by the
>>>>>> -    // virtual root node, will never be assigned a DFS number.
>>>>>> -    WorkStack.push_back(std::make_pair(ThisRoot,
>>>>>> ThisRoot->begin()));
>>>>>> +    // Both dominators and postdominators have a single root node.
>>>>>> In the case
>>>>>> +    // case of PostDominatorTree, this node is a virtual root.
>>>>>> +    WorkStack.push_back({ThisRoot, ThisRoot->begin()});
>>>>>> +
>>>>>> +    unsigned DFSNum = 0;
>>>>>>      ThisRoot->DFSNumIn = DFSNum++;
>>>>>>
>>>>>>      while (!WorkStack.empty()) {
>>>>>>        const DomTreeNodeBase<NodeT> *Node = WorkStack.back().first;
>>>>>> -      typename DomTreeNodeBase<NodeT>::const_iterator ChildIt =
>>>>>> -          WorkStack.back().second;
>>>>>> +      const auto ChildIt = WorkStack.back().second;
>>>>>>
>>>>>>        // If we visited all of the children of this node, "recurse"
>>>>>> back up the
>>>>>>        // stack setting the DFOutNum.
>>>>>> @@ -735,7 +732,7 @@ public:
>>>>>>          const DomTreeNodeBase<NodeT> *Child = *ChildIt;
>>>>>>          ++WorkStack.back().second;
>>>>>>
>>>>>> -        WorkStack.push_back(std::make_pair(Child, Child->begin()));
>>>>>> +        WorkStack.push_back({Child, Child->begin()});
>>>>>>          Child->DFSNumIn = DFSNum++;
>>>>>>        }
>>>>>>      }
>>>>>>
>>>>>> Modified: llvm/trunk/include/llvm/Suppor
>>>>>> t/GenericDomTreeConstruction.h
>>>>>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/
>>>>>> Support/GenericDomTreeConstruction.h?rev=314801&r1=314800&r2
>>>>>> =314801&view=diff
>>>>>> ============================================================
>>>>>> ==================
>>>>>> --- llvm/trunk/include/llvm/Support/GenericDomTreeConstruction.h
>>>>>> (original)
>>>>>> +++ llvm/trunk/include/llvm/Support/GenericDomTreeConstruction.h Tue
>>>>>> Oct  3 07:33:41 2017
>>>>>> @@ -1349,6 +1349,102 @@ struct SemiNCAInfo {
>>>>>>      return true;
>>>>>>    }
>>>>>>
>>>>>> +  // Check if the computed DFS numbers are correct. Note that DFS
>>>>>> info may not
>>>>>> +  // be valid, and when that is the case, we don't verify the
>>>>>> numbers.
>>>>>> +  static bool VerifyDFSNumbers(const DomTreeT &DT) {
>>>>>> +    if (!DT.DFSInfoValid || !DT.Parent)
>>>>>> +      return true;
>>>>>> +
>>>>>> +    const NodePtr RootBB = IsPostDom ? nullptr : DT.getRoots()[0];
>>>>>> +    const TreeNodePtr Root = DT.getNode(RootBB);
>>>>>> +
>>>>>> +    auto PrintNodeAndDFSNums = [](const TreeNodePtr TN) {
>>>>>> +      errs() << BlockNamePrinter(TN) << " {" << TN->getDFSNumIn() <<
>>>>>> ", "
>>>>>> +             << TN->getDFSNumOut() << '}';
>>>>>> +    };
>>>>>> +
>>>>>> +    // Verify the root's DFS In number. Although DFS numbering would
>>>>>> also work
>>>>>> +    // if we started from some other value, we assume 0-based
>>>>>> numbering.
>>>>>> +    if (Root->getDFSNumIn() != 0) {
>>>>>> +      errs() << "DFSIn number for the tree root is not:\n\t";
>>>>>> +      PrintNodeAndDFSNums(Root);
>>>>>> +      errs() << '\n';
>>>>>> +      errs().flush();
>>>>>> +      return false;
>>>>>> +    }
>>>>>> +
>>>>>> +    // For each tree node verify if children's DFS numbers cover
>>>>>> their parent's
>>>>>> +    // DFS numbers with no gaps.
>>>>>> +    for (const auto &NodeToTN : DT.DomTreeNodes) {
>>>>>> +      const TreeNodePtr Node = NodeToTN.second.get();
>>>>>> +
>>>>>> +      // Handle tree leaves.
>>>>>> +      if (Node->getChildren().empty()) {
>>>>>> +        if (Node->getDFSNumIn() + 1 != Node->getDFSNumOut()) {
>>>>>> +          errs() << "Tree leaf should have DFSOut = DFSIn + 1:\n\t";
>>>>>> +          PrintNodeAndDFSNums(Node);
>>>>>> +          errs() << '\n';
>>>>>> +          errs().flush();
>>>>>> +          return false;
>>>>>> +        }
>>>>>> +
>>>>>> +        continue;
>>>>>> +      }
>>>>>> +
>>>>>> +      // Make a copy and sort it such that it is possible to check
>>>>>> if there are
>>>>>> +      // no gaps between DFS numbers of adjacent children.
>>>>>> +      SmallVector<TreeNodePtr, 8> Children(Node->begin(),
>>>>>> Node->end());
>>>>>> +      std::sort(Children.begin(), Children.end(),
>>>>>> +                [](const TreeNodePtr Ch1, const TreeNodePtr Ch2) {
>>>>>> +                  return Ch1->getDFSNumIn() < Ch2->getDFSNumIn();
>>>>>> +                });
>>>>>> +
>>>>>> +      auto PrintChildrenError = [Node, &Children,
>>>>>> PrintNodeAndDFSNums](
>>>>>> +          const TreeNodePtr FirstCh, const TreeNodePtr SecondCh =
>>>>>> nullptr) {
>>>>>> +        assert(FirstCh);
>>>>>> +
>>>>>> +        errs() << "Incorrect DFS numbers for:\n\tParent ";
>>>>>> +        PrintNodeAndDFSNums(Node);
>>>>>> +
>>>>>> +        errs() << "\n\tChild ";
>>>>>> +        PrintNodeAndDFSNums(FirstCh);
>>>>>> +
>>>>>> +        if (SecondCh) {
>>>>>> +          errs() << "\n\tSecond child ";
>>>>>> +          PrintNodeAndDFSNums(SecondCh);
>>>>>> +        }
>>>>>> +
>>>>>> +        errs() << "\nAll children: ";
>>>>>> +        for (const TreeNodePtr Ch : Children) {
>>>>>> +          PrintNodeAndDFSNums(Ch);
>>>>>> +          errs() << ", ";
>>>>>> +        }
>>>>>> +
>>>>>> +        errs() << '\n';
>>>>>> +        errs().flush();
>>>>>> +      };
>>>>>> +
>>>>>> +      if (Children.front()->getDFSNumIn() != Node->getDFSNumIn() +
>>>>>> 1) {
>>>>>> +        PrintChildrenError(Children.front());
>>>>>> +        return false;
>>>>>> +      }
>>>>>> +
>>>>>> +      if (Children.back()->getDFSNumOut() + 1 !=
>>>>>> Node->getDFSNumOut()) {
>>>>>> +        PrintChildrenError(Children.back());
>>>>>> +        return false;
>>>>>> +      }
>>>>>> +
>>>>>> +      for (size_t i = 0, e = Children.size() - 1; i != e; ++i) {
>>>>>> +        if (Children[i]->getDFSNumOut() + 1 != Children[i +
>>>>>> 1]->getDFSNumIn()) {
>>>>>> +          PrintChildrenError(Children[i], Children[i + 1]);
>>>>>> +          return false;
>>>>>> +        }
>>>>>> +      }
>>>>>> +    }
>>>>>> +
>>>>>> +    return true;
>>>>>> +  }
>>>>>> +
>>>>>>    // Checks if for every edge From -> To in the graph
>>>>>>    //     NCD(From, To) == IDom(To) or To.
>>>>>>    bool verifyNCD(const DomTreeT &DT) {
>>>>>> @@ -1521,7 +1617,8 @@ bool Verify(const DomTreeT &DT) {
>>>>>>    SemiNCAInfo<DomTreeT> SNCA(nullptr);
>>>>>>    return SNCA.verifyRoots(DT) && SNCA.verifyReachability(DT) &&
>>>>>>           SNCA.VerifyLevels(DT) && SNCA.verifyNCD(DT) &&
>>>>>> -         SNCA.verifyParentProperty(DT) &&
>>>>>> SNCA.verifySiblingProperty(DT);
>>>>>> +         SNCA.verifyParentProperty(DT) &&
>>>>>> SNCA.verifySiblingProperty(DT) &&
>>>>>> +         SNCA.VerifyDFSNumbers(DT);
>>>>>>  }
>>>>>>
>>>>>>  }  // namespace DomTreeBuilder
>>>>>>
>>>>>>
>>>>>> _______________________________________________
>>>>>> llvm-commits mailing list
>>>>>> llvm-commits at lists.llvm.org
>>>>>> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-commits
>>>>>>
>>>>>
>>>>>
>>>>
>>>>
>>>> --
>>>> Jakub Kuderski
>>>>
>>>
>>>
>>
>>
>> --
>> Jakub Kuderski
>>
>
>
>
> --
> Jakub Kuderski
>
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