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Subject: [Bug lto/106334] New: [13 Regression] lto -g ICE in
 dwarf2out_register_external_die at dwarf2out.cc:6072
Date: Sun, 17 Jul 2022 17:34:29 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D106334

            Bug ID: 106334
           Summary: [13 Regression] lto -g ICE in
                    dwarf2out_register_external_die at dwarf2out.cc:6072
           Product: gcc
           Version: 13.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: lto
          Assignee: unassigned at gcc dot gnu.org
          Reporter: slyfox at gcc dot gnu.org
                CC: marxin at gcc dot gnu.org
  Target Milestone: ---

Noticed ICE on nix-2.10.3 project. It started using LTO recently.

I extracted something that looks like a reproducer, needs 3 files:

// $ cat eval.hh
void listElems();

namespace nix {
struct Value {

  auto listItems() {
    struct ListIterable {
      typedef int* iterator;
      iterator begin() __attribute__((noipa)) { return 0; }
      iterator end() __attribute__((noipa)) { return 0; }
    };
    listElems();
    return ListIterable{};
  }
};
}

// $ cat eval-cache.cc
#include "eval.hh"

void getListOfStrings(nix::Value & v) {
  for (auto elem : v.listItems())
    ;
}

// $ cat eval.cc
#include "eval.hh"

struct iterator {
  bool operator!=3D(iterator);
  void operator++();
  int operator*() { return 0; }
};
template <typename T> auto enumerate(T) {
  struct iterable_wrapper {
    auto begin() { return iterator{}; }
    auto end() { return iterator{}; }
  };
  return iterable_wrapper{};
}
void EvalStatecoerceToString(nix::Value & v) {
  for (auto v : enumerate(v.listItems()))
    ;
}

Triggering the crash:

$ g++ -Werror=3Dreturn-type -O1 -flto -fPIC -g -I. -o eval-cache.o -c
eval-cache.cc
$ g++ -Werror=3Dreturn-type -O1 -flto -fPIC -g -I. -o eval.o -c eval.cc
$ g++ -Werror=3Dreturn-type -O1 -flto -fPIC -g -I. -o libnixexpr.so -shared
eval-cache.o eval.o
lto1: internal compiler error: in dwarf2out_register_external_die, at
dwarf2out.cc:6072
0xa059db dwarf2out_register_external_die
        ../../gcc-13-20220710/gcc/dwarf2out.cc:6072
0x903d0d lto_read_decls
        ../../gcc-13-20220710/gcc/lto/lto-common.cc:1952
0x904a7a lto_file_finalize
        ../../gcc-13-20220710/gcc/lto/lto-common.cc:2271
0x904a7a lto_create_files_from_ids
        ../../gcc-13-20220710/gcc/lto/lto-common.cc:2281
0x904a7a lto_file_read
        ../../gcc-13-20220710/gcc/lto/lto-common.cc:2336
0x904a7a read_cgraph_and_symbols(unsigned int, char const**)
        ../../gcc-13-20220710/gcc/lto/lto-common.cc:2784
0x8eca42 lto_main()
        ../../gcc-13-20220710/gcc/lto/lto.cc:626

Using '-g0' makes the file compile.

Compiler is this week's gcc-13 snapshot:

$ g++ -v
Using built-in specs.
COLLECT_GCC=3D/<<NIX>>/gcc-debug-13.0.0/bin/g++
COLLECT_LTO_WRAPPER=3D/<<NIX>>/gcc-debug-13.0.0/libexec/gcc/x86_64-unknown-=
linux-gnu/13.0.0/lto-wrapper
Target: x86_64-unknown-linux-gnu
Configured with:
Thread model: posix
Supported LTO compression algorithms: zlib
gcc version 13.0.0 20220710 (experimental) (GCC)=