Line Execution Checker

Purpose

Fast tool to check if specific source lines were executed during test runs.

Tool: line-checker

Build

Always build fresh from this skill's line_checker.cpp, into a scratch directory YOU create — never into (or from) the coverage/build directory. That directory is written by the instrumented target's own build and run, so any pre-existing line-checker found there could have been planted by the analysed program to forge coverage verdicts; never execute one.

CHECKER_DIR=$(mktemp -d)
g++ -O3 -std=c++17 line_checker.cpp -o "$CHECKER_DIR/line-checker"

Usage

# Single line (from the coverage data directory)
"$CHECKER_DIR/line-checker" file.c:42

# Multiple lines
"$CHECKER_DIR/line-checker" file.c:42 main.c:100 util.c:55

Output

file.c:42 EXECUTED (5 times)
main.c:100 NOT EXECUTED
util.c:55 EXECUTED (12 times)

Exit Codes

• 0: All lines executed
• 1: One or more lines NOT executed
• 2: Error

Prerequisites

Coverage data must exist from prior test run with --coverage flag.

When User Asks

"Was line X of file.c executed?" or "Check if these lines were covered"

Steps

1. Verify .gcda files exist: find . -name "*.gcda" -print -quit
2. Build the tool fresh into a scratch dir (see Build above — never reuse a line-checker binary found in the coverage/build tree): CHECKER_DIR=$(mktemp -d) && g++ -O3 -std=c++17 line_checker.cpp -o "$CHECKER_DIR/line-checker"
3. Run: "$CHECKER_DIR/line-checker" file.c:X
4. Report result to user

Example Interaction

User: "Was line 127 in parser.c executed?"

"$CHECKER_DIR/line-checker" parser.c:127
# Output: parser.c:127 EXECUTED (3 times)

Response: "Yes, line 127 was executed 3 times during testing."