llama.cpp/docs/debugging-tests.md

How to run & debug a specific test without anything else to keep the feedback loop short?

Borrowing from the CI scripts to make something workflow specific, we have the following.

rm -rf build-ci-debug && mkdir build-ci-debug && cd build-ci-debug
cmake -DCMAKE_BUILD_TYPE=Debug -DLLAMA_CUDA=1 -DLLAMA_FATAL_WARNINGS=ON .. && cd ..
# runs faster
make -j
# if you see the "you don't have "cache" installed warning, install it to save immense amounts of time!"
cd tests

# The output of this command will give you the command & arguments needed to run GDB.
# -R test-tokenizer -> looks for all the test files named test-tokenizer* (R=Regex)
# -N -> "show-only" disables test execution & shows test commands that you can feed to GDB.
ctest -R test-tokenizer-0 -V -N
# OUPUT:
    # 1: Test command: /home/ubuntu/workspace/llama.cpp/bin/test-tokenizer-0 "/home/ubuntu/workspace/llama.cpp/tests/../models/ggml-vocab-llama-spm.gguf"
    # 1: Working Directory: .
    # Labels: main
    # Test #1: test-tokenizer-0-llama-spm

# Now that we have the command & arguments needed to run a test, we can debug it with GDB.
# I copied the command from the above output, your scenario will be different.
gdb --args /home/ubuntu/workspace/llama.cpp/bin/test-tokenizer-0 "/home/ubuntu/workspace/llama.cpp/tests/../models/ggml-vocab-llama-spm.gguf"

# In case you're struggling after this, GDB can tell you how to use it (>>> help) & it can do incredible things like inspect the variables of any stackframe previous to the current one to help you see what's led to the issue. GDB also makes it easy to revisit a debugging session (see below).