FST tracer produces empty file

[derchr]

Hello,

I want to confirm that I'm not using the tool incorrectly. When I run one of the examples (e.g., simple_system with the -t flag) that instantiates a tracer, I'm only getting empty fst traces (they are all exactly 119B in size, no matter which example I run). The ftr tracing part seems to be working fine.
However, when I switch the tracing format to SC_VCD, a valid VCD file is generated that can be opened by the regular trace file viewer. Am I doing something wrong?

I tested both the 2024.07 version and also the current development version. My SystemC version is 2.3.4.

[eyck]

Hi Derek, can you briefly describe the environment you are working in (OS, compiler, etc.)?

[derchr]

Sure, I'm on Fedora 41 and compiled the project using gcc 14.2.1. Both SystemC (2.3.4) itself and SCC is compiled with C++17.
The boost version is 1.83.0 and zlib-ng is 2.1.7. Is there any else information that might be useful?

[eyck]

I cannot verify this. I used a docker container:

docker pull fedora:41 && docker run --rm -ti fedora:41 bash
dnf install gcc g++  cmake ninja git -y
git clone -b develop --recursive https://github.com/Minres/SystemC-Components.git
cd SystemC-Components/
python3 -mvenv .venv
 . .venv/bin/activate
pip3 install 'conan<2.0'
cmake -S . -B build -DCMAKE_BUILD_TYPE=Debug -DCMAKE_CXX_STANDARD=17
cmake --build build -j12
build/examples/simple_system/simple_system -t

works well and produces a valid FST file. Even when moving fmt to version 11.0.1 and spdlog to 1.14 (using the changes from #60) the FST file gets created properly.

[derchr]

I did some tinkering and when enabling conan, it did also work for me. However, as soon as I link my system-installed SystemC instead of the one built by conan, it doesn't work anymore.
My originally used SystemC is just the plain, unmodified 2.3.4 version built and installed with CMake, so I tought it should work.

[eyck]

The problem is a bug in the SystemC cmake setup (accellera-official/systemc#24). You need to add -DENABLE_PHASE_CALLBACKS_TRACING=OFF when installing SystemC.
The other option is to build SCC with -DSC_WITH_PHASE_CALLBACK_TRACING=ON but this is not fully tested.

[derchr]

I see, thanks for pointing that out! Now it works for me.

Maybe this is something worth noting in the README, as this is a default setting set by SystemC? Other users might stumble upon this too.