[perf] Improve analyze file filter for header

[gzzi]

Automatic detection of source file affected by header is terribly slow. A complete analysis without the --file filter is 15 minutes. Specifying 40 headers with --file takes more than 1h to analyze. Our compilation database as ~1000 entry.

The bottle neck seem to be get_dependent_sources. As far as I understood, this function is called for each header sequentially and iterate over each entry of the compilation database to compute a dependency lookup table.

We could save the dependency lookup table and parallelize this process.

Easily reproducible with following bash script:

#!/bin/bash

function generate_db {
    echo "Generating database..."

    echo "[" > compile_commands.json

    for _ in {1..1000}; do
        echo "{\"directory\": \"$(pwd)\", \"command\": \"g++ dummy.cpp -c -o dummy.o\", \"file\": \"dummy.cpp\", \"output\": \"dummy.o\"}," >> compile_commands.json
    done
    echo "{\"directory\": \"$(pwd)\", \"command\": \"g++ single_entry.cpp -c -o dummy.o\", \"file\": \"single_entry.cpp\", \"output\": \"dummy.o\"}" >> compile_commands.json
    echo "]" >> compile_commands.json
}

generate_db
touch dummy.cpp
touch single_entry.cpp
touch dummy.hpp
touch dummy_2.hpp

echo "Full analysis... ------------------------------------------"
time CodeChecker analyze compile_commands.json -o ./reports
echo "Single source analysis... ------------------------------------------"
time CodeChecker analyze compile_commands.json -o ./reports --file single_entry.cpp
echo "Single header analysis... ------------------------------------------"
time CodeChecker analyze compile_commands.json -o ./reports --file dummy.hpp
echo "Two header analysis... ------------------------------------------"
time CodeChecker analyze compile_commands.json -o ./reports --file dummy.hpp dummy_2.hpp

Environment

❯ CodeChecker version
[INFO 2026-07-07 13:49:00] - CodeChecker analyzer version:
---------------------------------------------------------------
Kind                 | Version                                 
---------------------------------------------------------------
Base package version | 6.28.2                                  
Package build date   | 2026-06-29T08:05                        
Git commit ID (hash) | 13b2b26718497c13ad9987a5d71d7f2dcb9d270f
Git tag information  | 6.28.2                                  
---------------------------------------------------------------

[INFO 2026-07-07 13:49:00] - CodeChecker web version:
------------------------------------------------------------------------------
Kind                                | Version                                 
------------------------------------------------------------------------------
Base package version                | 6.28.2                                  
Package build date                  | 2026-06-29T08:05                        
Git commit ID (hash)                | 13b2b26718497c13ad9987a5d71d7f2dcb9d270f
Git tag information                 | 6.28.2                                  
Server supported Thrift API version | 6.71                                    
Client Thrift API version           | 6.71                                    
------------------------------------------------------------------------------
❯ cat /etc/lsb-release
DISTRIB_ID=Ubuntu
DISTRIB_RELEASE=24.04
DISTRIB_CODENAME=noble
DISTRIB_DESCRIPTION="Ubuntu 24.04.4 LTS"