[PATCH] D129997: [Local] Allow creating callbr with duplicate successors

Tue Jul 19 13:08:54 PDT 2022

nathanchance added a comment.

Sorry I didn't get a chance to report this until after it was merged (my first round of tests forgot to update Linux to fix some unrelated build breakage) but I see a crash in some PowerPC Linux kernel builds as a result of this change in `net/ceph/messenger_v2.c`. A reduced C reproducer below.

  struct ceph_connection_v2_info {
    int in_state;
  };
  struct ceph_connection {
    struct {
      struct ceph_connection_v2_info v2;
    };
  };
  int process_message_header_con_0;
  int ceph_con_in_msg_alloc(int *);
  int prepare_read_tail_plain() { return 2; }
  int process_message_header() {
    int skip = ceph_con_in_msg_alloc(&skip);
    if (skip)
      return 0;
    if (__builtin_constant_p(process_message_header_con_0))
      ;
    else
      asm goto("" : : : : __label_warn_on);
  __label_warn_on:
    return 1;
  }
  int __handle_control() {
    int ret = process_message_header();
    if (ret == 0)
      return 0;
    return prepare_read_tail_plain();
  }
  void ceph_con_v2_try_read(struct ceph_connection *con) {
    for (;;) {
      struct ceph_connection __trans_tmp_3 = *con;
      switch (__trans_tmp_3.v2.in_state)
      case 1:
        __handle_control();
    }
  }

  $ clang --target=powerpc64le-linux-gnu -fno-PIE -O2 -c -o /dev/null messenger_v2.i
  Use of %0 does not have a corresponding definition on every path:
  fatal error: error in backend: Use not jointly dominated by defs.
  PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace, preprocessed source, and associated run script.
  Stack dump:
  0.      Program arguments: clang --target=powerpc64le-linux-gnu -fno-PIE -O2 -c -o /dev/null messenger_v2.i
  1.      <eof> parser at end of file
  2.      Code generation
  3.      Running pass 'Function Pass Manager' on module 'messenger_v2.i'.
  4.      Running pass 'Live Interval Analysis' on function '@ceph_con_v2_try_read'
   #0 0x00005590013c98e3 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/home/nathan/tmp/tmp.A3o6TI3QI1/install/llvm/08860f525a2363ccd697ebb3ff59769e37b1be21/bin/clang-15+0x4fdc8e3)
   #1 0x00005590013c787e llvm::sys::RunSignalHandlers() (/home/nathan/tmp/tmp.A3o6TI3QI1/install/llvm/08860f525a2363ccd697ebb3ff59769e37b1be21/bin/clang-15+0x4fda87e)
   #2 0x0000559001349713 (anonymous namespace)::CrashRecoveryContextImpl::HandleCrash(int, unsigned long) CrashRecoveryContext.cpp:0:0
   #3 0x000055900134968f llvm::CrashRecoveryContext::HandleExit(int) (/home/nathan/tmp/tmp.A3o6TI3QI1/install/llvm/08860f525a2363ccd697ebb3ff59769e37b1be21/bin/clang-15+0x4f5c68f)
   #4 0x00005590013c40f7 llvm::sys::Process::Exit(int, bool) (/home/nathan/tmp/tmp.A3o6TI3QI1/install/llvm/08860f525a2363ccd697ebb3ff59769e37b1be21/bin/clang-15+0x4fd70f7)
   #5 0x0000558fff6a7772 (/home/nathan/tmp/tmp.A3o6TI3QI1/install/llvm/08860f525a2363ccd697ebb3ff59769e37b1be21/bin/clang-15+0x32ba772)
   #6 0x000055900134e599 llvm::report_fatal_error(llvm::Twine const&, bool) (/home/nathan/tmp/tmp.A3o6TI3QI1/install/llvm/08860f525a2363ccd697ebb3ff59769e37b1be21/bin/clang-15+0x4f61599)
   #7 0x000055900134e486 (/home/nathan/tmp/tmp.A3o6TI3QI1/install/llvm/08860f525a2363ccd697ebb3ff59769e37b1be21/bin/clang-15+0x4f61486)
   #8 0x0000559000717b8c llvm::LiveRangeCalc::findReachingDefs(llvm::LiveRange&, llvm::MachineBasicBlock&, llvm::SlotIndex, unsigned int, llvm::ArrayRef<llvm::SlotIndex>) (/home/nathan/tmp/tmp.A3o6TI3QI1/install/llvm/08860f525a2363ccd697ebb3ff59769e37b1be21/bin/clang-15+0x432ab8c)
   #9 0x0000559000716c96 llvm::LiveRangeCalc::extend(llvm::LiveRange&, llvm::SlotIndex, unsigned int, llvm::ArrayRef<llvm::SlotIndex>) (/home/nathan/tmp/tmp.A3o6TI3QI1/install/llvm/08860f525a2363ccd697ebb3ff59769e37b1be21/bin/clang-15+0x4329c96)
  #10 0x000055900071a465 llvm::LiveIntervalCalc::extendToUses(llvm::LiveRange&, llvm::Register, llvm::LaneBitmask, llvm::LiveInterval*) (/home/nathan/tmp/tmp.A3o6TI3QI1/install/llvm/08860f525a2363ccd697ebb3ff59769e37b1be21/bin/clang-15+0x432d465)
  #11 0x000055900071a084 llvm::LiveIntervalCalc::calculate(llvm::LiveInterval&, bool) (/home/nathan/tmp/tmp.A3o6TI3QI1/install/llvm/08860f525a2363ccd697ebb3ff59769e37b1be21/bin/clang-15+0x432d084)
  #12 0x0000559000703542 llvm::LiveIntervals::computeVirtRegInterval(llvm::LiveInterval&) (/home/nathan/tmp/tmp.A3o6TI3QI1/install/llvm/08860f525a2363ccd697ebb3ff59769e37b1be21/bin/clang-15+0x4316542)
  #13 0x0000559000702131 llvm::LiveIntervals::computeVirtRegs() (/home/nathan/tmp/tmp.A3o6TI3QI1/install/llvm/08860f525a2363ccd697ebb3ff59769e37b1be21/bin/clang-15+0x4315131)
  #14 0x0000559000701f11 llvm::LiveIntervals::runOnMachineFunction(llvm::MachineFunction&) (/home/nathan/tmp/tmp.A3o6TI3QI1/install/llvm/08860f525a2363ccd697ebb3ff59769e37b1be21/bin/clang-15+0x4314f11)
  #15 0x0000559000778cbd llvm::MachineFunctionPass::runOnFunction(llvm::Function&) (/home/nathan/tmp/tmp.A3o6TI3QI1/install/llvm/08860f525a2363ccd697ebb3ff59769e37b1be21/bin/clang-15+0x438bcbd)
  #16 0x0000559000c263d7 llvm::FPPassManager::runOnFunction(llvm::Function&) (/home/nathan/tmp/tmp.A3o6TI3QI1/install/llvm/08860f525a2363ccd697ebb3ff59769e37b1be21/bin/clang-15+0x48393d7)
  #17 0x0000559000c2de81 llvm::FPPassManager::runOnModule(llvm::Module&) (/home/nathan/tmp/tmp.A3o6TI3QI1/install/llvm/08860f525a2363ccd697ebb3ff59769e37b1be21/bin/clang-15+0x4840e81)
  #18 0x0000559000c26de5 llvm::legacy::PassManagerImpl::run(llvm::Module&) (/home/nathan/tmp/tmp.A3o6TI3QI1/install/llvm/08860f525a2363ccd697ebb3ff59769e37b1be21/bin/clang-15+0x4839de5)
  #19 0x0000559001bccafd clang::EmitBackendOutput(clang::DiagnosticsEngine&, clang::HeaderSearchOptions const&, clang::CodeGenOptions const&, clang::TargetOptions const&, clang::LangOptions const&, llvm::StringRef, llvm::Module*, clang::BackendAction, std::unique_ptr<llvm::raw_pwrite_stream, std::default_delete<llvm::raw_pwrite_stream>>) (/home/nathan/tmp/tmp.A3o6TI3QI1/install/llvm/08860f525a2363ccd697ebb3ff59769e37b1be21/bin/clang-15+0x57dfafd)
  #20 0x0000559001fbec6e clang::BackendConsumer::HandleTranslationUnit(clang::ASTContext&) CodeGenAction.cpp:0:0
  #21 0x000055900283e564 clang::ParseAST(clang::Sema&, bool, bool) (/home/nathan/tmp/tmp.A3o6TI3QI1/install/llvm/08860f525a2363ccd697ebb3ff59769e37b1be21/bin/clang-15+0x6451564)
  #22 0x0000559001f02220 clang::FrontendAction::Execute() (/home/nathan/tmp/tmp.A3o6TI3QI1/install/llvm/08860f525a2363ccd697ebb3ff59769e37b1be21/bin/clang-15+0x5b15220)
  #23 0x0000559001e752cf clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) (/home/nathan/tmp/tmp.A3o6TI3QI1/install/llvm/08860f525a2363ccd697ebb3ff59769e37b1be21/bin/clang-15+0x5a882cf)
  #24 0x0000559001fb8312 clang::ExecuteCompilerInvocation(clang::CompilerInstance*) (/home/nathan/tmp/tmp.A3o6TI3QI1/install/llvm/08860f525a2363ccd697ebb3ff59769e37b1be21/bin/clang-15+0x5bcb312)
  #25 0x0000558fff6a7240 cc1_main(llvm::ArrayRef<char const*>, char const*, void*) (/home/nathan/tmp/tmp.A3o6TI3QI1/install/llvm/08860f525a2363ccd697ebb3ff59769e37b1be21/bin/clang-15+0x32ba240)
  #26 0x0000558fff6a4f0f ExecuteCC1Tool(llvm::SmallVectorImpl<char const*>&) driver.cpp:0:0
  #27 0x0000559001cf4842 void llvm::function_ref<void ()>::callback_fn<clang::driver::CC1Command::Execute(llvm::ArrayRef<llvm::Optional<llvm::StringRef>>, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char>>*, bool*) const::$_1>(long) Job.cpp:0:0
  #28 0x0000559001349627 llvm::CrashRecoveryContext::RunSafely(llvm::function_ref<void ()>) (/home/nathan/tmp/tmp.A3o6TI3QI1/install/llvm/08860f525a2363ccd697ebb3ff59769e37b1be21/bin/clang-15+0x4f5c627)
  #29 0x0000559001cf439f clang::driver::CC1Command::Execute(llvm::ArrayRef<llvm::Optional<llvm::StringRef>>, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char>>*, bool*) const (/home/nathan/tmp/tmp.A3o6TI3QI1/install/llvm/08860f525a2363ccd697ebb3ff59769e37b1be21/bin/clang-15+0x590739f)
  #30 0x0000559001cb42fe clang::driver::Compilation::ExecuteCommand(clang::driver::Command const&, clang::driver::Command const*&, bool) const (/home/nathan/tmp/tmp.A3o6TI3QI1/install/llvm/08860f525a2363ccd697ebb3ff59769e37b1be21/bin/clang-15+0x58c72fe)
  #31 0x0000559001cb45ae clang::driver::Compilation::ExecuteJobs(clang::driver::JobList const&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*>>&, bool) const (/home/nathan/tmp/tmp.A3o6TI3QI1/install/llvm/08860f525a2363ccd697ebb3ff59769e37b1be21/bin/clang-15+0x58c75ae)
  #32 0x0000559001cd05d0 clang::driver::Driver::ExecuteCompilation(clang::driver::Compilation&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*>>&) (/home/nathan/tmp/tmp.A3o6TI3QI1/install/llvm/08860f525a2363ccd697ebb3ff59769e37b1be21/bin/clang-15+0x58e35d0)
  #33 0x0000558fff6a458b clang_main(int, char**) (/home/nathan/tmp/tmp.A3o6TI3QI1/install/llvm/08860f525a2363ccd697ebb3ff59769e37b1be21/bin/clang-15+0x32b758b)
  #34 0x00007f4538e10550 __libc_start_call_main (/lib64/libc.so.6+0x23550)
  #35 0x00007f4538e10609 __libc_start_main at GLIBC_2.2.5 (/lib64/libc.so.6+0x23609)
  #36 0x0000558fff6a1b35 _start /build/glibc/src/glibc/csu/../sysdeps/x86_64/start.S:117:0
  clang-15: error: clang frontend command failed with exit code 70 (use -v to see invocation)
  ClangBuiltLinux clang version 15.0.0 (https://github.com/llvm/llvm-project 08860f525a2363ccd697ebb3ff59769e37b1be21)
  Target: powerpc64le-unknown-linux-gnu
  Thread model: posix
  InstalledDir: /home/nathan/tmp/tmp.A3o6TI3QI1/install/llvm/08860f525a2363ccd697ebb3ff59769e37b1be21/bin
  clang-15: note: diagnostic msg: Error generating preprocessed source(s) - no preprocessable inputs.

The same reproducer does not trigger on the parent commit. `-fno-PIE` is needed for reproducing the crash, it doesn't happen without it. If there is any more information that I can provide or patches I can test, please let me know!

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D129997/new/

https://reviews.llvm.org/D129997