[llvm] r273585 - Preserve DebugInfo when replacing values in DAGCombiner

[Ismail Donmez via llvm-commits]

Hi,

This is most certainly a memory corruption:

#0  llvm::SelectionDAG::TransferDbgValues (this=<optimized out>,
From=..., To=...)
    at ../lib/CodeGen/SelectionDAG/SelectionDAG.cpp:6666
6666        if (Dbg->getKind() == SDDbgValue::SDNODE &&
(gdb) print Dbg
$1 = (llvm::SDDbgValue *) 0x4545454545454545


The value 0x45 is what I set as MALLOC_PERTURB_ [0] value. You can
easily reproduce this on Linux with malloc debugging, just do

export MALLOC_CHECK_=3
export MALLOC_PERTURB_=69

See https://www.gnu.org/software/libc/manual/html_node/Heap-Consistency-Checking.html
for more details.

On Thu, Jul 14, 2016 at 8:02 PM, Ismail Donmez <ismail at i10z.com> wrote:
> Hi,
>
> On Thu, Jun 23, 2016 at 8:52 PM, Nirav Dave via llvm-commits
> <llvm-commits at lists.llvm.org> wrote:
>> Author: niravd
>> Date: Thu Jun 23 12:52:57 2016
>> New Revision: 273585
>>
>> URL: http://llvm.org/viewvc/llvm-project?rev=273585&view=rev
>> Log:
>> Preserve DebugInfo when replacing values in DAGCombiner
>>
>> Recommiting after correcting over-eager Debug Value transfer fixing PR28270.
>>
>> [DAG] Previously debug values would transfer debuginfo for the selected
>> start node for a replacement which allows for debug to be dropped.
>>
>> Push debug value transfer to occur with node/value replacement in
>> SelectionDAG, remove now extraneous transfers of debug values.
>>
>> This refixes PR9817 which was being incompletely checked in the
>> testsuite.
>
> Can't get a reproducer easily yet but this is crashing clang in stage2
> bootstrap while compiling llvm-symbolizer.cpp  with a backtrace like:
>
> #0 0x00007ff3a922cec8 llvm::sys::PrintStackTrace(llvm::raw_ostream&)
> /home/abuild/rpmbuild/BUILD/llvm/stage1/../lib/Support/Unix/Signals.inc:402:13
> #1 0x00007ff3a922ad26 bool std::__1::operator!=<std::__1::pair<void
> (*)(void*), void*>*>(std::__1::__wrap_iter<std::__1::pair<void
> (*)(void*), void*>*> const&, std::__1::__wrap_iter<std::__1::pair<void
> (*)(void*), void*>*> const&)
> /usr/bin/../include/c++/v1/iterator:1364:12
> #2 0x00007ff3a922ad26 llvm::sys::RunSignalHandlers()
> /home/abuild/rpmbuild/BUILD/llvm/stage1/../lib/Support/Signals.cpp:44:0
> #3 0x00007ff3a922d501 SignalHandler(int)
> /home/abuild/rpmbuild/BUILD/llvm/stage1/../lib/Support/Unix/Signals.inc:256:1
> #4 0x00007ff3a8ce4ef0 __restore_rt (/lib64/libpthread.so.0+0x10ef0)
> #5 0x00007ff3a779d7b3
> llvm::SelectionDAG::TransferDbgValues(llvm::SDValue, llvm::SDValue)
> /home/abuild/rpmbuild/BUILD/llvm/stage1/../lib/CodeGen/SelectionDAG/SelectionDAG.cpp:6666:46
> #6 0x00007ff3a779d551 llvm::SDValue::operator==(llvm::SDValue const&)
> const /home/abuild/rpmbuild/BUILD/llvm/stage1/../include/llvm/CodeGen/SelectionDAGNodes.h:126:27
> #7 0x00007ff3a779d551
> llvm::SelectionDAG::ReplaceAllUsesWith(llvm::SDValue, llvm::SDValue)
> /home/abuild/rpmbuild/BUILD/llvm/stage1/../lib/CodeGen/SelectionDAG/SelectionDAG.cpp:6312:0
> #8 0x00007ff3a768d6e0 (anonymous
> namespace)::SelectionDAGLegalize::ReplaceNode(llvm::SDValue,
> llvm::SDValue) /home/abuild/rpmbuild/BUILD/llvm/stage1/../lib/CodeGen/SelectionDAG/LegalizeDAG.cpp:190:9
> #9 0x00007ff3a768b21f (anonymous
> namespace)::SelectionDAGLegalize::LegalizeOp(llvm::SDNode*)
> /home/abuild/rpmbuild/BUILD/llvm/stage1/../lib/CodeGen/SelectionDAG/LegalizeDAG.cpp:1128:11
> #10 0x00007ff3a768a585 llvm::SelectionDAG::Legalize()
> /home/abuild/rpmbuild/BUILD/llvm/stage1/../lib/CodeGen/SelectionDAG/LegalizeDAG.cpp:4428:28
> #11 0x00007ff3a77b1d34 llvm::TimeRegion::~TimeRegion()
> /home/abuild/rpmbuild/BUILD/llvm/stage1/../include/llvm/Support/Timer.h:148:9
> #12 0x00007ff3a77b1d34 llvm::SelectionDAGISel::CodeGenAndEmitDAG()
> /home/abuild/rpmbuild/BUILD/llvm/stage1/../lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp:824:0
> #13 0x00007ff3a77b027d
> llvm::SelectionDAGISel::SelectAllBasicBlocks(llvm::Function const&)
> /home/abuild/rpmbuild/BUILD/llvm/stage1/../lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp:1482:7
> #14 0x00007ff3a77ac88b
> llvm::SelectionDAGISel::runOnMachineFunction(llvm::MachineFunction&)
> /home/abuild/rpmbuild/BUILD/llvm/stage1/../lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp:505:36
> #15 0x00007ff3aa6a4451 (anonymous
> namespace)::X86DAGToDAGISel::runOnMachineFunction(llvm::MachineFunction&)
> /home/abuild/rpmbuild/BUILD/llvm/stage1/../lib/Target/X86/X86ISelDAGToDAG.cpp:176:7
> #16 0x00007ff3a9ca0aa5
> llvm::MachineFunctionPass::runOnFunction(llvm::Function&)
> /home/abuild/rpmbuild/BUILD/llvm/stage1/../lib/CodeGen/MachineFunctionPass.cpp:60:13
> #17 0x00007ff3a995df04
> llvm::FPPassManager::runOnFunction(llvm::Function&)
> /home/abuild/rpmbuild/BUILD/llvm/stage1/../lib/IR/LegacyPassManager.cpp:1526:23
> #18 0x00007ff3a995e14b llvm::FPPassManager::runOnModule(llvm::Module&)
> /home/abuild/rpmbuild/BUILD/llvm/stage1/../lib/IR/LegacyPassManager.cpp:1547:13
> #19 0x00007ff3a995e5b3 (anonymous
> namespace)::MPPassManager::runOnModule(llvm::Module&)
> /home/abuild/rpmbuild/BUILD/llvm/stage1/../lib/IR/LegacyPassManager.cpp:1603:23
> #20 0x00007ff3a995e5b3
> llvm::legacy::PassManagerImpl::run(llvm::Module&)
> /home/abuild/rpmbuild/BUILD/llvm/stage1/../lib/IR/LegacyPassManager.cpp:1706:0
> #21 0x00007ff3a86332ed (anonymous
> namespace)::EmitAssemblyHelper::EmitAssembly(clang::BackendAction,
> llvm::raw_pwrite_stream*)
> /home/abuild/rpmbuild/BUILD/llvm/stage1/../tools/clang/lib/CodeGen/BackendUtil.cpp:767:3
> #22 0x00007ff3a86332ed
> clang::EmitBackendOutput(clang::DiagnosticsEngine&,
> clang::CodeGenOptions const&, clang::TargetOptions const&,
> clang::LangOptions const&, llvm::DataLayout const&, llvm::Module*,
> clang::BackendAction, llvm::raw_pwrite_stream*)
> /home/abuild/rpmbuild/BUILD/llvm/stage1/../tools/clang/lib/CodeGen/BackendUtil.cpp:778:0
> #23 0x00007ff3a88317dd
> clang::BackendConsumer::HandleTranslationUnit(clang::ASTContext&)
> /home/abuild/rpmbuild/BUILD/llvm/stage1/../tools/clang/lib/CodeGen/CodeGenAction.cpp:178:7
> #24 0x00007ff3a661d376
> std::__1::enable_if<(is_move_constructible<bool>::value) &&
> (is_move_assignable<bool>::value), void>::type
> std::__1::swap<bool>(bool&, bool&)
> /usr/bin/../include/c++/v1/type_traits:4206:9
> #25 0x00007ff3a661d376 clang::ParseAST(clang::Sema&, bool, bool)
> /home/abuild/rpmbuild/BUILD/llvm/stage1/../tools/clang/lib/Parse/ParseAST.cpp:169:0
> #26 0x00007ff3a83b3ee6 clang::FrontendAction::Execute()
> /home/abuild/rpmbuild/BUILD/llvm/stage1/../tools/clang/lib/Frontend/FrontendAction.cpp:461:7
> #27 0x00007ff3a8377c21
> clang::CompilerInstance::ExecuteAction(clang::FrontendAction&)
> /home/abuild/rpmbuild/BUILD/llvm/stage1/../tools/clang/lib/Frontend/CompilerInstance.cpp:877:7
> #28 0x00007ff3aa8c3bb9
> clang::ExecuteCompilerInvocation(clang::CompilerInstance*)
> /home/abuild/rpmbuild/BUILD/llvm/stage1/../tools/clang/lib/FrontendTool/ExecuteCompilerInvocation.cpp:241:18
> #29 0x000000000040ec2a cc1_main(llvm::ArrayRef<char const*>, char
> const*, void*) /home/abuild/rpmbuild/BUILD/llvm/stage1/../tools/clang/tools/driver/cc1_main.cpp:116:13
> #30 0x000000000040d895 ExecuteCC1Tool(llvm::ArrayRef<char const*>,
> llvm::StringRef)
> /home/abuild/rpmbuild/BUILD/llvm/stage1/../tools/clang/tools/driver/driver.cpp:301:12
> #31 0x000000000040d895 main
> /home/abuild/rpmbuild/BUILD/llvm/stage1/../tools/clang/tools/driver/driver.cpp:382:0
> #32 0x00007ff3a795d741 __libc_start_main (/lib64/libc.so.6+0x20741)
> #33 0x000000000040a829 _start
> /home/abuild/rpmbuild/BUILD/glibc-2.23/csu/../sysdeps/x86_64/start.S:121:0
>
> Hopefully will have more ideas later on.