Constant ValueID not recognized

[petrhosek]

Bugzilla Link	51724
Version	trunk
OS	All
Attachments	Clang crash reproducer

Extended Description

We ran into this failure when trying to use -fmerge-functions.

Constant ValueID not recognized.
UNREACHABLE executed at /src/clang-llvm/llvm-project/llvm/lib/Transforms/Utils/FunctionComparator.cpp:399!
PLEASE submit a bug report to https://bugs.llvm.org/ and include the crash backtrace, preprocessed source, and associated run script.
Stack dump:
0.      Program arguments: ../bin/clang++ -cc1 -triple x86_64-unknown-fuchsia -emit-obj -massembler-fatal-warnings --mrelax-relocations -disable-free -disable-llvm-verifier -discard-value-names -main-file-name zircon_platform_buffer.cc -mrelocation-model pic -pic-level 2 -pic-is-pie -mframe-pointer=none -fno-rounding-math -mconstructor-aliases -munwind-tables -target-cpu x86-64-v2 -mllvm -x86-branches-within-32B-boundaries -debug-info-kind=constructor -dwarf-version=5 -debugger-tuning=gdb -mllvm -crash-diagnostics-dir=clang-crashreports -ffunction-sections -fdata-sections -fcoverage-compilation-dir=. -sys-header-deps -D TOOLCHAIN_VERSION=dO8igrHyLDfgq8txd8Qx0mI9oJqFLswAMLcIBKLF6TYC -D _LIBCPP_DISABLE_VISIBILITY_ANNOTATIONS -D NDEBUG=1 -D _LIBCPP_ENABLE_THREAD_SAFETY_ANNOTATIONS=1 -D MAGMA_DEBUG_INTERNAL_USE_ONLY=0 -D MAGMA_ENABLE_TRACING -O3 -Wall -Wextra -Wnewline-eof -Wconversion -Wimplicit-fallthrough -Wno-unused-parameter -Wno-sign-conversion -Wno-c99-designator -Werror -Wno-error=deprecated-declarations -Wthread-safety -Wno-deprecated-copy -Wno-suggest-override -std=c++17 -fdeprecated-macro -fdebug-compilation-dir=. -ferror-limit 19 -fvisibility hidden -fvisibility-inlines-hidden -fsanitize=safe-stack -stack-protector 2 -ftrivial-auto-var-init=pattern -fno-rtti -fgnuc-version=4.2.1 -fno-legacy-pass-manager -fcolor-diagnostics -vectorize-loops -vectorize-slp -debug-info-kind=constructor -fmerge-functions -faddrsig -D__GCC_HAVE_DWARF2_CFI_ASM=1 -x c++ zircon_platform_buffer-84a54b.cpp
1.      <eof> parser at end of file
2.      Optimizer
 #&#8203;0 0x00000000092b3a5a llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) /src/clang-llvm/llvm-project/llvm/lib/Support/Unix/Signals.inc:565:11
 #&#8203;1 0x00000000092b3b6b PrintStackTraceSignalHandler(void*) /src/clang-llvm/llvm-project/llvm/lib/Support/Unix/Signals.inc:632:1
 #&#8203;2 0x00000000092b2423 llvm::sys::RunSignalHandlers() /src/clang-llvm/llvm-project/llvm/lib/Support/Signals.cpp:97:5
 #&#8203;3 0x00000000092b41a5 SignalHandler(int) /src/clang-llvm/llvm-project/llvm/lib/Support/Unix/Signals.inc:407:1
 #&#8203;4 0x00007feff6aac140 __restore_rt (/lib/x86_64-linux-gnu/libpthread.so.0+0x14140)
 #&#8203;5 0x00007feff67b9ce1 raise (/lib/x86_64-linux-gnu/libc.so.6+0x3bce1)
 #&#8203;6 0x00007feff67a3537 abort (/lib/x86_64-linux-gnu/libc.so.6+0x25537)
 #&#8203;7 0x00000000091daff0 llvm::install_out_of_memory_new_handler() /src/clang-llvm/llvm-project/llvm/lib/Support/ErrorHandling.cpp:194:0
 #&#8203;8 0x0000000009332127 llvm::FunctionComparator::cmpConstants(llvm::Constant const*, llvm::Constant const*) const /src/clang-llvm/llvm-project/llvm/lib/Transforms/Utils/FunctionComparator.cpp:402:1
 #&#8203;9 0x0000000009331d87 llvm::FunctionComparator::cmpConstants(llvm::Constant const*, llvm::Constant const*) const /src/clang-llvm/llvm-project/llvm/lib/Transforms/Utils/FunctionComparator.cpp:357:15
#&#8203;10 0x00000000093322a7 llvm::FunctionComparator::cmpValues(llvm::Value const*, llvm::Value const*) const /src/clang-llvm/llvm-project/llvm/lib/Transforms/Utils/FunctionComparator.cpp:767:5
#&#8203;11 0x0000000009333da1 llvm::FunctionComparator::cmpBasicBlocks(llvm::BasicBlock const*, llvm::BasicBlock const*) const /src/clang-llvm/llvm-project/llvm/lib/Transforms/Utils/FunctionComparator.cpp:807:17
#&#8203;12 0x0000000009334565 llvm::FunctionComparator::compare() /src/clang-llvm/llvm-project/llvm/lib/Transforms/Utils/FunctionComparator.cpp:896:13
#&#8203;13 0x0000000008894caa (anonymous namespace)::MergeFunctions::FunctionNodeCmp::operator()((anonymous namespace)::FunctionNode const&, (anonymous namespace)::FunctionNode const&) const /src/clang-llvm/llvm-project/llvm/lib/Transforms/IPO/MergeFunctions.cpp:220:29
#&#8203;14 0x00000000088947ef std::__2::__tree_node_base<void*>*& std::__2::__tree<(anonymous namespace)::FunctionNode, (anonymous namespace)::MergeFunctions::FunctionNodeCmp, std::__2::allocator<(anonymous namespace)::FunctionNode> >::__find_equal<(anonymous namespace)::FunctionNode>(std::__2::__tree_end_node<std::__2::__tree_node_base<void*>*>*&, (anonymous namespace)::FunctionNode const&) /usr/local/google/home/phosek/fuchsia/prebuilt/third_party/clang/linux-x64/bin/../include/c++/v1/__tree:1975:17
#&#8203;15 0x00000000088946bc std::__2::pair<std::__2::__tree_iterator<(anonymous namespace)::FunctionNode, std::__2::__tree_node<(anonymous namespace)::FunctionNode, void*>*, long>, bool> std::__2::__tree<(anonymous namespace)::FunctionNode, (anonymous namespace)::MergeFunctions::FunctionNodeCmp, std::__2::allocator<(anonymous namespace)::FunctionNode> >::__emplace_unique_key_args<(anonymous namespace)::FunctionNode, (anonymous namespace)::FunctionNode>((anonymous namespace)::FunctionNode const&, (anonymous namespace)::FunctionNode&&) /usr/local/google/home/phosek/fuchsia/prebuilt/third_party/clang/linux-x64/bin/../include/c++/v1/__tree:2091:26
#&#8203;16 0x00000000088945fe std::__2::__tree<(anonymous namespace)::FunctionNode, (anonymous namespace)::MergeFunctions::FunctionNodeCmp, std::__2::allocator<(anonymous namespace)::FunctionNode> >::__insert_unique((anonymous namespace)::FunctionNode&&) /usr/local/google/home/phosek/fuchsia/prebuilt/third_party/clang/linux-x64/bin/../include/c++/v1/__tree:1260:16
#&#8203;17 0x0000000008893c8d std::__2::set<(anonymous namespace)::FunctionNode, (anonymous namespace)::MergeFunctions::FunctionNodeCmp, std::__2::allocator<(anonymous namespace)::FunctionNode> >::insert((anonymous namespace)::FunctionNode&&) /usr/local/google/home/phosek/fuchsia/prebuilt/third_party/clang/linux-x64/bin/../include/c++/v1/set:687:25
#&#8203;18 0x00000000088937a6 (anonymous namespace)::MergeFunctions::insert(llvm::Function*) /src/clang-llvm/llvm-project/llvm/lib/Transforms/IPO/MergeFunctions.cpp:905:14
#&#8203;19 0x0000000008892378 (anonymous namespace)::MergeFunctions::runOnModule(llvm::Module&) /src/clang-llvm/llvm-project/llvm/lib/Transforms/IPO/MergeFunctions.cpp:450:20
#&#8203;20 0x0000000008891da8 llvm::MergeFunctionsPass::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) /src/clang-llvm/llvm-project/llvm/lib/Transforms/IPO/MergeFunctions.cpp:327:7
#&#8203;21 0x000000000aecbbc7 llvm::detail::PassModel<llvm::Module, llvm::MergeFunctionsPass, llvm::PreservedAnalyses, llvm::AnalysisManager<llvm::Module> >::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) /src/clang-llvm/llvm-project/llvm/include/llvm/IR/PassManagerInternal.h:85:17
#&#8203;22 0x000000000869523d llvm::PassManager<llvm::Module, llvm::AnalysisManager<llvm::Module> >::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) /src/clang-llvm/llvm-project/llvm/include/llvm/IR/PassManager.h:509:16
#&#8203;23 0x0000000009f5728e (anonymous namespace)::EmitAssemblyHelper::EmitAssemblyWithNewPassManager(clang::BackendAction, std::__2::unique_ptr<llvm::raw_pwrite_stream, std::__2::default_delete<llvm::raw_pwrite_stream> >) /src/clang-llvm/llvm-project/clang/lib/CodeGen/BackendUtil.cpp:1495:5
#&#8203;24 0x0000000009f54df9 clang::EmitBackendOutput(clang::DiagnosticsEngine&, clang::HeaderSearchOptions const&, clang::CodeGenOptions const&, clang::TargetOptions const&, clang::LangOptions const&, llvm::StringRef, llvm::Module*, clang::BackendAction, std::__2::unique_ptr<llvm::raw_pwrite_stream, std::__2::default_delete<llvm::raw_pwrite_stream> >) /src/clang-llvm/llvm-project/clang/lib/CodeGen/BackendUtil.cpp:1661:5
#&#8203;25 0x000000000a3c2af7 clang::BackendConsumer::HandleTranslationUnit(clang::ASTContext&) /src/clang-llvm/llvm-project/clang/lib/CodeGen/CodeGenAction.cpp:338:7
#&#8203;26 0x000000000caa5ac1 clang::ParseAST(clang::Sema&, bool, bool) /src/clang-llvm/llvm-project/clang/lib/Parse/ParseAST.cpp:178:12
#&#8203;27 0x000000000a1f74cc clang::ASTFrontendAction::ExecuteAction() /src/clang-llvm/llvm-project/clang/lib/Frontend/FrontendAction.cpp:1060:1
#&#8203;28 0x000000000a3be6b2 clang::CodeGenAction::ExecuteAction() /src/clang-llvm/llvm-project/clang/lib/CodeGen/CodeGenAction.cpp:1072:5
#&#8203;29 0x000000000a1f6efc clang::FrontendAction::Execute() /src/clang-llvm/llvm-project/clang/lib/Frontend/FrontendAction.cpp:955:7
#&#8203;30 0x000000000a133a01 clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) /src/clang-llvm/llvm-project/clang/lib/Frontend/CompilerInstance.cpp:974:23
#&#8203;31 0x000000000a3ad21e clang::ExecuteCompilerInvocation(clang::CompilerInstance*) /src/clang-llvm/llvm-project/clang/lib/FrontendTool/ExecuteCompilerInvocation.cpp:278:8
#&#8203;32 0x0000000005c92384 cc1_main(llvm::ArrayRef<char const*>, char const*, void*) /src/clang-llvm/llvm-project/clang/tools/driver/cc1_main.cpp:246:13
#&#8203;33 0x0000000005c84dab ExecuteCC1Tool(llvm::SmallVectorImpl<char const*>&) /src/clang-llvm/llvm-project/clang/tools/driver/driver.cpp:338:5
#&#8203;34 0x0000000005c84015 main /src/clang-llvm/llvm-project/clang/tools/driver/driver.cpp:409:5
#&#8203;35 0x00007feff67a4d0a __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x26d0a)
#&#8203;36 0x0000000005c8385a _start (../bin/clang+++0x5c8385a)

[petrhosek]

I have managed to reduce the reproducer down to this:

# 7 "" 3
typedef __UINT64_TYPE__ a;
template <class b>
struct c {
  using d = b *;
};
template <class b>
struct e {
  template <class f>
  e(f g) : ab(g) {}
  b h() { return ab; }
  b ab;
};
template <class ac>
class i : e<ac>, e<int> {
 public:
  typedef e<ac> j;
  template <class k, class m>
  i(k g, m) : j(g), e(0) {}
  ac ad() { return static_cast<j &>(*this).h(); }
};
template <class b, class = int>
class n {
  typedef typename c<b>::d ah;
  i<ah> ai;

 public:
  n(ah g) : ai(g, int()) {}
  template <class f, class ak>
  n(n<f, ak> g) : ai(g.al(), 0) {}
  ah operator->() { return ai.ad(); }
  ah al() {
    ah l = ai.ad();
    return l;
  }
};
template <class b>
struct o {
  typedef n<b> an;
};
template <class b, class... ao>
typename o<b>::an fn1(ao... g) {
  return new b(g...);
}
class p {
 public:
  class F {
   public:
    virtual a av();
    virtual a aw();
    static n<F> ax() { return ay(); }
    static n<F> ay();
  };
  static a az();
};
class q {
 public:
  class r : public p::F {
   public:
    r(int) {}
    a av();
    a aw();
  };
};
n<p::F> p::F::ay() { return fn1<q::r>(int()); }
a q::r::av() {}
a p::az() { return F::ax()->aw(); }
a s() { return p::F::ax()->av(); }

[petrhosek]

Reproducer reduced by C-Reduce.

[petrhosek]

I have managed to further reduce this down to:

class a {
 public:
  virtual int f();
  virtual int g();
  static a* x();
  static a* y();
};
class b : public a {
 public:
  int f() override;
};
class c {
 public:
  static int z();
};
int c::z() { return a::x()->g(); }
a* a::x() { return y(); }
a* a::y() { return new b(); }
int b::f() { return 0; }
int s() { return a::x()->f(); }

I was hoping to further reduce this as bitcode using llvm-reduce but I hit issue #57815 while doing so.

Further debugging revealed that the issue is likely due to handling of dso_local_equivalent in FunctionComparator. Specifically, we aren't currently handling dso_local_equivalent in this switch:

llvm-project/llvm/lib/Transforms/Utils/FunctionComparator.cpp

Line 405 in 30b550f

default: // Unknown constant, abort.

dso_local_equivalent was only introduced somewhat recently and it looks like when we introduced it, we forgot to update that switch. This also makes me wonder if we similarly need to handle no_cfi, which got introduced recently , in the same switch.

cc @PiJoules

[xgupta]

Didn't reproduce on the trunk - https://godbolt.org/z/dna7KfdTP.

[petrhosek]

This was addressed by 21b03bf.