core: Collect and print stacktrace after fatal error

build-support/custom-modules/ns3-compiler-workarounds.cmake

@@ -3,3 +3,58 @@
 # SPDX-License-Identifier: GPL-2.0-only
 #
 # Author: Gabriel Ferreira <gabrielcarvfer@gmail.com>
+
+include(CheckCXXSourceCompiles)
+
+# Some compilers (e.g. GCC <= 15) do not link std::stacktrace by default. If the
+# sample program can be linked, it means it is indeed linked by default.
+# Otherwise, we link it manually.
+# https://en.cppreference.com/w/cpp/header/stacktrace
+set(CMAKE_REQUIRED_FLAGS -std=c++23)
+check_cxx_source_compiles(
+  "
+  #if __has_include(<stacktrace>)
+  int main()
+  {
+    return 0;
+  }
+  #endif
+  "
+  STACKTRACE_LIBRARY_ENABLED
+)
+if(STACKTRACE_LIBRARY_ENABLED)
+  set(stacktrace_flags)
+  if(GCC)
+    if(CMAKE_CXX_COMPILER_VERSION VERSION_LESS "12.0.0")
+      # GCC does not support stacktracing
+    elseif(CMAKE_CXX_COMPILER_VERSION VERSION_LESS "14.0.0")
+      set(stacktrace_flags -lstdc++_libbacktrace)
+    else()
+      set(stacktrace_flags -lstdc++exp)
+    endif()
+  elseif(CLANG)
+    set(stacktrace_flags -lstdc++_libbacktrace)
+  else()
+    # Most likely MSVC, which does not need custom flags for this
+  endif()
+  set(CMAKE_REQUIRED_LIBRARIES ${stacktrace_flags})
+  string(REPLACE ";" " " CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS}")
+  check_cxx_source_compiles(
+    "
+    #include <iostream>
+    #include <stacktrace>
+
+    int main()
+    {
+      std::cout << std::stacktrace::current() << std::endl;
+      return 0;
+    }
+    "
+    STACKTRACE_LIBRARY_IS_LINKED
+  )
+
+  if(STACKTRACE_LIBRARY_IS_LINKED)
+    add_definitions(-DSTACKTRACE_LIBRARY_IS_LINKED=1)
+    link_libraries(${stacktrace_flags})
+  endif()
+endif()

src/core/model/fatal-error.h

@@ -17,6 +17,23 @@
 #include <iostream>
 #include <string_view>
 
+// If stacktrace is available, print it on fatal errors
+#ifdef STACKTRACE_LIBRARY_IS_LINKED
+#include <stacktrace>
+/**
+ * @brief Macro prints the current stack trace to standard error.
+ *
+ * This macro is defined only if the stacktrace library is linked.
+ */
+
+#define PRINT_STACKTRACE std::cerr << std::stacktrace::current() << std::endl
+#else
+/**
+ * @brief Macro does nothing if stacktrace library is not available.
+ */
+#define PRINT_STACKTRACE
+#endif
+
 /**
  * @file
  * @ingroup fatal
@@ -84,6 +101,7 @@ constexpr std::string_view NS_FATAL_MSG{"NS_FATAL, terminating"};
         if (fatal)                                                                                 \
         {                                                                                          \
             std::cerr << ns3::NS_FATAL_MSG << std::endl;                                           \
+            PRINT_STACKTRACE;                                                                      \
             std::terminate();                                                                      \
         }                                                                                          \
     } while (false)