Debugging C code with Valgrind

The best way of ensuring that an application compiled from C code does not have memory leaks and does not access invalid memory addresses is to run it through Valgrind. In case of errors, Valgrind will show the exact lines of bugs if the applications were compiled with debugging symbols. Hence, before debugging nvimcom or nvimserver code, we have to recompile them without optimization and with debugging symbols, and a script will make this task easier (adjust the values of R_INCLUDE_DIR, R_LIBRARY_DIR, and RNVIM_PATH):

make_nvimcom_for_valgrind.sh:

#!/bin/sh

R_INCLUDE_DIR="/usr/share/R/include"
R_LIBRARY_DIR="$HOME/R/x86_64-pc-linux-gnu-library/4.3"
RNVIM_PATH="$HOME/.local/share/nvim/lazy/R.nvim"

cd "$RNVIM_PATH/nvimcom/src"

gcc -I"$R_INCLUDE_DIR" -DNDEBUG -fpic -g -c nvimcom.c -o nvimcom.o
gcc -I"$R_INCLUDE_DIR" -DNDEBUG -fpic -g -c rd2md.c -o rd2md.o
gcc -I"$R_INCLUDE_DIR" -DNDEBUG -fpic -g -c common.c -o common.o
gcc -shared -o "$R_LIBRARY_DIR/nvimcom/libs/nvimcom.so" nvimcom.o rd2md.o common.o
rm -f nvimcom.o rd2md.o common.o

cd apps
gcc -pthread -std=gnu99 -g -Wall complete.c data_structures.c logging.c obbr.c \
    rnvimserver.c tcp.c utilities.c ../common.c \
    -o "$R_LIBRARY_DIR/nvimcom/bin/rnvimserver"

Then, to run the rnvimserver through Valgrind, change the file R.nvim/lua/r/server.lua and comment out the code that runs the rnvimserver directly and uncomment the code that runs it through Valgrind:

    require("r.job").start( "Server", {
            "valgrind",
            "--leak-check=full",
            "--log-file=/tmp/rnvimserver_valgrind_log",
            rns_path, }, rns_opts)
    -- require("r.job").start("Server", { rns_path }, rns_opts)

Similarly, to run R (and, consequently, nvimcom) through Valgrind, put in your R.nvim config:

  R_args = {"-d", "'valgrind --leak-check=full --log-file=/dev/shm/R_valgrind_log'"},

Finally, run R.nvim as usual and inspect the log files at the end of the session or use tail to follow the live output of Valgrind:

tail -f /tmp/rnvimserver_valgrind_log