[llvm] r336419 - CallGraphSCCPass: iterate over all functions.
Evgenii Stepanov via llvm-commits
llvm-commits at lists.llvm.org
Tue Jul 10 13:33:20 PDT 2018
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/
> Transforms/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
> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-commits
>
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