[llvm] r336419 - CallGraphSCCPass: iterate over all functions.
Galina Kistanova via llvm-commits
llvm-commits at lists.llvm.org
Thu Jul 12 12:01:21 PDT 2018
Hello Tim,
This commit has introduced nondeterminism. Please see
http://lab.llvm.org:8011/builders/clang-with-thin-lto-ubuntu or
http://lab.llvm.org:8011/builders/clang-with-lto-ubuntu build bots.
This is in addition to those other problems mentioned already, or maybe
some of the other problems are exposed because of this.
Since the problem is around for quite long now, maybe it worth reverting
till you will figure out what's wrong and how to fix it?
Thanks
Galina
On Tue, Jul 10, 2018 at 1:33 PM, Evgenii Stepanov via llvm-commits <
llvm-commits at lists.llvm.org> wrote:
> Hi Tim,
>
> MSan bootstrap bot has been randomly crashing lately with the following
> trace:
>
> 3. Running pass 'CallGraph Pass Manager' on module
> '/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm/lib/Target/Hexagon/
> HexagonCommonGEP.cpp'.
> #0 0x00005602f79f5cfa llvm::sys::PrintStackTrace(llvm::raw_ostream&)
> (/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm_
> build0/bin/clang-7+0x24f5cfa)
> #1 0x00005602f79f42c5 llvm::sys::RunSignalHandlers()
> (/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm_
> build0/bin/clang-7+0x24f42c5)
> #2 0x00005602f79f43dc SignalHandler(int) (/b/sanitizer-x86_64-linux-
> bootstrap-msan/build/llvm_build0/bin/clang-7+0x24f43dc)
> #3 0x00007f63daa840c0 __restore_rt (/lib/x86_64-linux-gnu/
> libpthread.so.0+0x110c0)
> #4 0x00005602f6edf38e llvm::scc_iterator<llvm::CallGraph*,
> llvm::GraphTraits<llvm::CallGraph*> >::DFSVisitChildren()
> (/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm_
> build0/bin/clang-7+0x19df38e)
> #5 0x00005602f6edf5aa llvm::scc_iterator<llvm::CallGraph*,
> llvm::GraphTraits<llvm::CallGraph*> >::GetNextSCC()
> (/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm_
> build0/bin/clang-7+0x19df5aa)
> #6 0x00005602f6ee05ed (anonymous namespace)::CGPassManager::runOnModule(llvm::Module&)
> (/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm_
> build0/bin/clang-7+0x19e05ed)
> #7 0x00005602f74ca5fd llvm::legacy::PassManagerImpl::run(llvm::Module&)
> (/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm_
> build0/bin/clang-7+0x1fca5fd)
> #8 0x00005602f7bde5c1 (anonymous namespace)::EmitAssemblyHelper::
> EmitAssembly(clang::BackendAction, std::unique_ptr<llvm::raw_pwrite_stream,
> std::default_delete<llvm::raw_pwrite_stream> >)
> (/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm_
> build0/bin/clang-7+0x26de5c1)
> #9 0x00005602f7bdfdf0 clang::EmitBackendOutput(clang::DiagnosticsEngine&,
> clang::HeaderSearchOptions const&, clang::CodeGenOptions const&,
> clang::TargetOptions const&, clang::LangOptions const&, llvm::DataLayout
> const&, llvm::Module*, clang::BackendAction, std::unique_ptr<llvm::raw_pwrite_stream,
> std::default_delete<llvm::raw_pwrite_stream> >)
> (/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm_
> build0/bin/clang-7+0x26dfdf0)
> #10 0x00005602f836f264 clang::BackendConsumer::
> HandleTranslationUnit(clang::ASTContext&) (/b/sanitizer-x86_64-linux-
> bootstrap-msan/build/llvm_build0/bin/clang-7+0x2e6f264)
> #11 0x00005602f8b37fa9 clang::ParseAST(clang::Sema&, bool, bool)
> (/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm_
> build0/bin/clang-7+0x3637fa9)
> #12 0x00005602f836e4d9 clang::CodeGenAction::ExecuteAction()
> (/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm_
> build0/bin/clang-7+0x2e6e4d9)
> #13 0x00005602f800da7e clang::FrontendAction::Execute()
> (/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm_
> build0/bin/clang-7+0x2b0da7e)
> #14 0x00005602f7fd9496 clang::CompilerInstance::ExecuteAction(clang::FrontendAction&)
> (/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm_
> build0/bin/clang-7+0x2ad9496)
> #15 0x00005602f80ad511 clang::ExecuteCompilerInvocation(clang::CompilerInstance*)
> (/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm_
> build0/bin/clang-7+0x2bad511)
> #16 0x00005602f614c080 cc1_main(llvm::ArrayRef<char const*>, char const*,
> void*) (/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm_
> build0/bin/clang-7+0xc4c080)
> #17 0x00005602f60c1a22 main (/b/sanitizer-x86_64-linux-
> bootstrap-msan/build/llvm_build0/bin/clang-7+0xbc1a22)
> #18 0x00007f63d98312e1 __libc_start_main (/lib/x86_64-linux-gnu/libc.
> so.6+0x202e1)
> #19 0x00005602f61480aa _start (/b/sanitizer-x86_64-linux-
> bootstrap-msan/build/llvm_build0/bin/clang-7+0xc480aa)
> clang-7: error: unable to execute command: Segmentation fault
>
> The crash happens roughly in 1 out of 5-to-10 builds, see history here:
> http://lab.llvm.org:8011/builders/sanitizer-x86_64-linux-bootstrap-msan?
> numbuilds=300
>
> The earliest it happened was this build at r336432:
> http://lab.llvm.org:8011/builders/sanitizer-x86_64-
> linux-bootstrap-msan/builds/5763
>
> I suspect that this change could be the culprit. Could you take a look?
>
>
> On Fri, Jul 6, 2018 at 1:04 AM, Tim Northover via llvm-commits <
> llvm-commits at lists.llvm.org> wrote:
>
>> Author: tnorthover
>> Date: Fri Jul 6 01:04:47 2018
>> New Revision: 336419
>>
>> URL: http://llvm.org/viewvc/llvm-project?rev=336419&view=rev
>> Log:
>> CallGraphSCCPass: iterate over all functions.
>>
>> Previously we only iterated over functions reachable from the set of
>> external functions in the module. But since some of the passes under
>> this (notably the always-inliner and coroutine lowerer) are required for
>> correctness, they need to run over everything.
>>
>> This just adds an extra layer of iteration over the CallGraph to keep
>> track of which functions we've already visited and get the next batch of
>> SCCs.
>>
>> Should fix PR38029.
>>
>> Modified:
>> llvm/trunk/include/llvm/ADT/SCCIterator.h
>> llvm/trunk/lib/Analysis/CallGraphSCCPass.cpp
>> llvm/trunk/test/Transforms/Inline/always-inline.ll
>>
>> Modified: llvm/trunk/include/llvm/ADT/SCCIterator.h
>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/
>> ADT/SCCIterator.h?rev=336419&r1=336418&r2=336419&view=diff
>> ============================================================
>> ==================
>> --- llvm/trunk/include/llvm/ADT/SCCIterator.h (original)
>> +++ llvm/trunk/include/llvm/ADT/SCCIterator.h Fri Jul 6 01:04:47 2018
>> @@ -90,6 +90,7 @@ class scc_iterator : public iterator_fac
>> /// Compute the next SCC using the DFS traversal.
>> void GetNextSCC();
>>
>> +public:
>> scc_iterator(NodeRef entryN) : visitNum(0) {
>> DFSVisitOne(entryN);
>> GetNextSCC();
>> @@ -98,12 +99,6 @@ class scc_iterator : public iterator_fac
>> /// End is when the DFS stack is empty.
>> scc_iterator() = default;
>>
>> -public:
>> - static scc_iterator begin(const GraphT &G) {
>> - return scc_iterator(GT::getEntryNode(G));
>> - }
>> - static scc_iterator end(const GraphT &) { return scc_iterator(); }
>> -
>> /// Direct loop termination test which is more efficient than
>> /// comparison with \c end().
>> bool isAtEnd() const {
>> @@ -222,16 +217,25 @@ bool scc_iterator<GraphT, GT>::hasLoop()
>> return false;
>> }
>>
>> -/// Construct the begin iterator for a deduced graph type T.
>> +/// Construct the begin iterator for a deduced graph type T, starting
>> from its
>> +/// entry node.
>> template <class T> scc_iterator<T> scc_begin(const T &G) {
>> - return scc_iterator<T>::begin(G);
>> + return scc_iterator<T>(GraphTraits<T>::getEntryNode(G));
>> }
>>
>> -/// Construct the end iterator for a deduced graph type T.
>> +/// Construct the begin iterator for a graph type T, starting from the
>> specified
>> +/// node.
>> +template <class T, class U = GraphTraits<T>>
>> +scc_iterator<T, U> scc_begin(typename U::NodeRef N) {
>> + return scc_iterator<T>(N);
>> +}
>> +
>> + /// Construct the end iterator for a deduced graph type T.
>> template <class T> scc_iterator<T> scc_end(const T &G) {
>> - return scc_iterator<T>::end(G);
>> + return scc_iterator<T>();
>> }
>>
>> +
>> } // end namespace llvm
>>
>> #endif // LLVM_ADT_SCCITERATOR_H
>>
>> Modified: llvm/trunk/lib/Analysis/CallGraphSCCPass.cpp
>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/
>> CallGraphSCCPass.cpp?rev=336419&r1=336418&r2=336419&view=diff
>> ============================================================
>> ==================
>> --- llvm/trunk/lib/Analysis/CallGraphSCCPass.cpp (original)
>> +++ llvm/trunk/lib/Analysis/CallGraphSCCPass.cpp Fri Jul 6 01:04:47 2018
>> @@ -17,6 +17,7 @@
>>
>> #include "llvm/Analysis/CallGraphSCCPass.h"
>> #include "llvm/ADT/DenseMap.h"
>> +#include "llvm/ADT/DenseSet.h"
>> #include "llvm/ADT/SCCIterator.h"
>> #include "llvm/ADT/Statistic.h"
>> #include "llvm/Analysis/CallGraph.h"
>> @@ -63,6 +64,10 @@ public:
>> /// whether any of the passes modifies the module, and if so, return
>> true.
>> bool runOnModule(Module &M) override;
>>
>> + /// Execute all of the passes scheduled for execution on a given SCC.
>> Return
>> + /// true if any passes modify the module.
>> + bool runOnSCC(CallGraphSCC &SCC, CallGraph &CG);
>> +
>> using ModulePass::doInitialization;
>> using ModulePass::doFinalization;
>>
>> @@ -448,51 +453,78 @@ bool CGPassManager::RunAllPassesOnSCC(Ca
>> bool CGPassManager::runOnModule(Module &M) {
>> CallGraph &CG = getAnalysis<CallGraphWrapperPass>().getCallGraph();
>> bool Changed = doInitialization(CG);
>> -
>> - // Walk the callgraph in bottom-up SCC order.
>> - scc_iterator<CallGraph*> CGI = scc_begin(&CG);
>>
>> - CallGraphSCC CurSCC(CG, &CGI);
>> - while (!CGI.isAtEnd()) {
>> - // Copy the current SCC and increment past it so that the pass can
>> hack
>> - // on the SCC if it wants to without invalidating our iterator.
>> - const std::vector<CallGraphNode *> &NodeVec = *CGI;
>> - CurSCC.initialize(NodeVec);
>> - ++CGI;
>> -
>> - // At the top level, we run all the passes in this pass manager on
>> the
>> - // functions in this SCC. However, we support iterative compilation
>> in the
>> - // case where a function pass devirtualizes a call to a function.
>> For
>> - // example, it is very common for a function pass (often GVN or
>> instcombine)
>> - // to eliminate the addressing that feeds into a call. With that
>> improved
>> - // information, we would like the call to be an inline candidate,
>> infer
>> - // mod-ref information etc.
>> - //
>> - // Because of this, we allow iteration up to a specified iteration
>> count.
>> - // This only happens in the case of a devirtualized call, so we only
>> burn
>> - // compile time in the case that we're making progress. We also
>> have a hard
>> - // iteration count limit in case there is crazy code.
>> - unsigned Iteration = 0;
>> - bool DevirtualizedCall = false;
>> - do {
>> - LLVM_DEBUG(if (Iteration) dbgs()
>> - << " SCCPASSMGR: Re-visiting SCC, iteration #" <<
>> Iteration
>> - << '\n');
>> - DevirtualizedCall = false;
>> - Changed |= RunAllPassesOnSCC(CurSCC, CG, DevirtualizedCall);
>> - } while (Iteration++ < MaxIterations && DevirtualizedCall);
>> -
>> - if (DevirtualizedCall)
>> - LLVM_DEBUG(dbgs() << " CGSCCPASSMGR: Stopped iteration after "
>> - << Iteration
>> - << " times, due to -max-cg-scc-iterations\n");
>> + DenseSet<const Function *> Visited;
>>
>> - MaxSCCIterations.updateMax(Iteration);
>> + CallGraph::iterator INext;
>> + for (auto I = CG.begin(), E = CG.end(); I != E;) {
>> + // Walk the callgraph in bottom-up SCC order.
>> + auto CGI = scc_begin<CallGraph *>(I->second.get());
>> +
>> + CallGraphSCC CurSCC(CG, &CGI);
>> + while (!CGI.isAtEnd()) {
>> + const std::vector<CallGraphNode *> &NodeVec = *CGI;
>> +
>> + // Record that we've seen this set of functions so we don't run
>> the pass
>> + // twice.
>> + for (auto *Elt : NodeVec)
>> + Visited.insert(Elt->getFunction());
>> +
>> + // Copy the current SCC and increment past it so that the pass can
>> hack
>> + // on the SCC if it wants to without invalidating our iterator.
>> + CurSCC.initialize(NodeVec);
>> + ++CGI;
>> +
>> + // If we've got all functions reachable from our chosen initial
>> node,
>> + // calculate the next node we need to search from now before parts
>> of the
>> + // graph are invalidated.
>> + if (CGI.isAtEnd()) {
>> + do
>> + ++I;
>> + while (I != E && Visited.count(I->first));
>> + }
>> +
>> + Changed |= runOnSCC(CurSCC, CG);
>> + }
>> }
>> +
>> Changed |= doFinalization(CG);
>> return Changed;
>> }
>>
>> +bool CGPassManager::runOnSCC(CallGraphSCC &CurSCC, CallGraph &CG) {
>> + bool Changed = false;
>> +
>> + // At the top level, we run all the passes in this pass manager on the
>> + // functions in this SCC. However, we support iterative compilation
>> in the
>> + // case where a function pass devirtualizes a call to a function. For
>> + // example, it is very common for a function pass (often GVN or
>> instcombine)
>> + // to eliminate the addressing that feeds into a call. With that
>> improved
>> + // information, we would like the call to be an inline candidate, infer
>> + // mod-ref information etc.
>> + //
>> + // Because of this, we allow iteration up to a specified iteration
>> count.
>> + // This only happens in the case of a devirtualized call, so we only
>> burn
>> + // compile time in the case that we're making progress. We also have
>> a hard
>> + // iteration count limit in case there is crazy code.
>> + unsigned Iteration = 0;
>> + bool DevirtualizedCall = false;
>> + do {
>> + LLVM_DEBUG(if (Iteration) dbgs()
>> + << " SCCPASSMGR: Re-visiting SCC, iteration #" <<
>> Iteration
>> + << '\n');
>> + DevirtualizedCall = false;
>> + Changed |= RunAllPassesOnSCC(CurSCC, CG, DevirtualizedCall);
>> + } while (Iteration++ < MaxIterations && DevirtualizedCall);
>> +
>> + if (DevirtualizedCall)
>> + LLVM_DEBUG(dbgs() << " CGSCCPASSMGR: Stopped iteration after " <<
>> Iteration
>> + << " times, due to -max-cg-scc-iterations\n");
>> +
>> + MaxSCCIterations.updateMax(Iteration);
>> + return Changed;
>> +}
>> +
>> /// Initialize CG
>> bool CGPassManager::doInitialization(CallGraph &CG) {
>> bool Changed = false;
>>
>> Modified: llvm/trunk/test/Transforms/Inline/always-inline.ll
>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transfor
>> ms/Inline/always-inline.ll?rev=336419&r1=336418&r2=336419&view=diff
>> ============================================================
>> ==================
>> --- llvm/trunk/test/Transforms/Inline/always-inline.ll (original)
>> +++ llvm/trunk/test/Transforms/Inline/always-inline.ll Fri Jul 6
>> 01:04:47 2018
>> @@ -316,3 +316,10 @@ define void @outer14() {
>> call void @inner14()
>> ret void
>> }
>> +
>> +define internal i32 @outer15() {
>> +; CHECK-LABEL: @outer15
>> +; CHECK: ret i32 1
>> + %res = call i32 @inner1()
>> + ret i32 %res
>> +}
>>
>>
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>> llvm-commits at lists.llvm.org
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>>
>
>
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