undefined reference to `absl::lts_20240116::raw_log_internal::internal_log_function[abi:cxx11]'

[dfarley1]

Describe the issue

I'm attempting to integrate a btree_multiset into our project. So far I haven't needed to build or link the abseil project itself, the btree types seem to be header-only for the most part (yay!).

However, once I got to testing I turned on ASan and ran into this compilation error:

/usr/bin/x86_64-pc-linux-gnu-ld.bfd: obj/blockmap_btree.o: in function `void absl::lts_20240116::container_internal::btree_iterator_generation_info_enabled::assert_valid_generation<absl::lts_20240116::container_internal::btree_node<absl::lts_20240116::container_internal::set_params<blockmap_btree_entry, std::less<blockmap_btree_entry>, std::allocator<blockmap_btree_entry>, 256, true> > >(absl::lts_20240116::container_internal::btree_node<absl::lts_20240116::container_internal::set_params<blockmap_btree_entry, std::less<blockmap_btree_entry>, std::allocator<blockmap_btree_entry>, 256, true> > const*) const':
/depot/out/Asan/../../vendor/abseil-cpp/absl/container/internal/btree.h:1082: undefined reference to `absl::lts_20240116::raw_log_internal::internal_log_function[abi:cxx11]'
clang-16: error: linker command failed with exit code 1 (use -v to see invocation)

I don't actually see any definition of internal_log_function, so I'm guessing it's generated or templated out somewhere during the full abseil build? In any case we don't need or want the logging at all, so I was hoping to basically

#define ABSL_INTERNAL_LOG(severity, message) assert(false, message)
#include "absl/container/btree_set.h"

in our code. Unfortunately that leads to a 'ABSL_INTERNAL_LOG' macro redefined error since there's no #ifdef check first.

Since this is the only instance of logging in the btree types, I went ahead and swapped it out with an assert() that I think is more consistent with the rest of the btree code. Is there any interest in upstreaming this change and/or adding the ability to disable internal logging so that the btree containers can keep being header-only?

diff --git a/absl/container/internal/btree.h b/absl/container/internal/btree.h
index 91df57a3..d590e4a4 100644
--- a/absl/container/internal/btree.h
+++ b/absl/container/internal/btree.h
@@ -58,7 +58,6 @@
 #include <type_traits>
 #include <utility>

-#include "absl/base/internal/raw_logging.h"
 #include "absl/base/macros.h"
 #include "absl/container/internal/common.h"
 #include "absl/container/internal/common_policy_traits.h"
@@ -1078,12 +1077,9 @@ class btree_iterator_generation_info_enabled {

   template <typename Node>
   void assert_valid_generation(const Node *node) const {
-    if (node != nullptr && node->generation() != generation_) {
-      ABSL_INTERNAL_LOG(
-          FATAL,
-          "Attempting to use an invalidated iterator. The corresponding b-tree "
-          "container has been mutated since this iterator was constructed.");
-    }
+    // Attempting to use an invalidated iterator. The corresponding b-tree
+    // container has been mutated since this iterator was constructed.
+    assert(node == nullptr || node->generation() == generation_);
   }

Steps to reproduce the problem

I tried to repro on godbolt.org, but that correctly links in the full library. I did a straight up git clone into my vendor/ folder and started using it without any build config:

#include "absl/container/btree_set.h"

struct blockmap_btree_entry {
    uint32_t time_sec;
    uint32_t blockno;
};
absl::btree_multiset<blockmap_btree_entry> btree = ...

What version of Abseil are you using?

20240116.2

What operating system and version are you using?

Linux, custom Gentoo

What compiler and version are you using?

gcc version 12.3.1 20230825 (Gentoo 12.3.1_p20230825 p2)
clang version 16.0.6

What build system are you using?

GNU Make 4.4.1

Additional context

No response

[derekmauro]

Since you are using make instead of CMake and mention header-only, I'm going to guess that you forgot to link a library. But I can't help you since you did not provide reproduction instructions.

[dfarley1]

$ cat ./btree_test.cc 
#include <cstdio>
#include "absl/container/btree_set.h"

using namespace std;

struct blockmap_btree_entry {
    uint32_t time_sec;
    uint32_t blockno;

    bool
    operator <(const blockmap_btree_entry &other) const
    {
        return this->time_sec < other.time_sec;
    }
};

using blockmap_t = absl::btree_multiset<blockmap_btree_entry>;

int
main()
{
    blockmap_t btree{};
    btree.insert(blockmap_btree_entry{0, 0});
    btree.insert(blockmap_btree_entry{0, 1});

    printf("btree=");
    for (auto it = btree.cbegin(); it != btree.cend(); it++) {
        printf("(%u %u), ", it->time_sec, it->blockno);
    }
    printf("\n");
}


$ clang++ -Wall -Werror -iquote "/depot/vendor/abseil-cpp/" -O2 -fsanitize=address -fsanitize=undefined btree_test.cc -o ./btree_test
/usr/bin/x86_64-pc-linux-gnu-ld.bfd: /tmp/btree_test-f3ff71.o: in function `void absl::lts_20240116::container_internal::btree_iterator_generation_info_enabled::assert_valid_generation<absl::lts_20240116::container_internal::btree_node<absl::lts_20240116::container_internal::set_params<blockmap_btree_entry, std::less<blockmap_btree_entry>, std::allocator<blockmap_btree_entry>, 256, true> > >(absl::lts_20240116::container_internal::btree_node<absl::lts_20240116::container_internal::set_params<blockmap_btree_entry, std::less<blockmap_btree_entry>, std::allocator<blockmap_btree_entry>, 256, true> > const*) const':
btree_test.cc:(.text._ZNK4absl12lts_2024011618container_internal38btree_iterator_generation_info_enabled23assert_valid_generationINS1_10btree_nodeINS1_10set_paramsI20blockmap_btree_entrySt4lessIS6_ESaIS6_ELi256ELb1EEEEEEEvPKT_[_ZNK4absl12lts_2024011618container_internal38btree_iterator_generation_info_enabled23assert_valid_generationINS1_10btree_nodeINS1_10set_paramsI20blockmap_btree_entrySt4lessIS6_ESaIS6_ELi256ELb1EEEEEEEvPKT_]+0x231): undefined reference to `absl::lts_20240116::raw_log_internal::internal_log_function[abi:cxx11]'
clang-16: error: linker command failed with exit code 1 (use -v to see invocation)

There's a minimal repro, sorry about that!

Since you are using make instead of CMake and mention header-only, I'm going to guess that you forgot to link a library.

Initially I did forget to link it, but then I realized that it works fine until I turn on ASan. I understand that not linking might not be supported or something that y'all want to even entertain, but I thought I'd mention it since it's the only instance in the btree code where you choose to log instead of assert() on usage errors like this.

For example, I also ran into the strict-weak-ordering checks in checked_compare::() and the asserts there were super helpful. I don't know if I would notice an iterator issue as immediately since it's just a log message that gets buried in the rest of my program's output.