cargo-cov doesn't work

[stasos24]

Command:

cargo cov -- show fuzz/target/<target triple>/release/my_compiler \
    --format=html \
    -instr-profile=fuzz/coverage/my_compiler/coverage.profdata \
    > index.html

Error response:

error: no such subcommand: `cov`

        Did you mean `c`?

[madig]

I "solved" this by running llvm-cov manually, like so (also install rustfilt):

/Users/user/.rustup/toolchains/nightly-x86_64-apple-darwin/lib/rustlib/x86_64-apple-darwin/bin/llvm-cov show fuzz/target/x86_64-apple-darwin/release/my_compiler \
                                         --format=html \
                                         -Xdemangler=rustfilt \
                                         --ignore-filename-regex="\.cargo" \
                                         -instr-profile=fuzz/coverage/my_compiler/coverage.profdata \
                                         > index.html

Use the llvm-cov binary you made the coverage with.

[jyn514]

hmm, that didn't work for me.

; llvm-cov show --instr-profile=/Users/jyn/src/inventory/fuzz/coverage/my_fuzz_target/coverage.profdata  --format=html -Xdemangler=rustfilt /Users/jyn/.local/lib/cargo/target/aarch64-apple-darwin/release/my_fuzz_target
error: Failed to load coverage: '/Users/jyn/.local/lib/cargo/target/aarch64-apple-darwin/release/my_fuzz_target': No coverage data found
; file /Users/jyn/.local/lib/cargo/target/aarch64-apple-darwin/release/my_fuzz_target
/Users/jyn/.local/lib/cargo/target/aarch64-apple-darwin/release/my_fuzz_target: Mach-O 64-bit executable arm64

[jix]

I was also getting the No coverage data found error, and it seems that the binary compiled with fuzzing instrumentation is at a different path from the main fuzzing binary now, but the documentation was never updated.

For me I had to change target/x86_64-unknown-linux-gnu/release/target_name to target/x86_64-unknown-linux-gnu/coverage/x86_64-unknown-linux-gnu/release/target_name (yes that includes the target triple twice) to make llvm-cov work, which makes sense when only the latter is compiled with coverage instrumentation.

[DJDuque]

I tried:

llvm-cov show target/x86_64-unknown-linux-gnu/release/fuzz_target_1 --format=html -Xdemangler=rustfilt -instr-profile=coverage/fuzz_target_1/coverage.profdata > index.html

And I get:

error: Failed to load coverage: 'coverage/fuzz_target_1/coverage.profdata': unsupported instrumentation profile format version

[0xdeafbeef]

#!/bin/bash
set -e

# Check if the correct number of arguments is provided
if [ "$#" -ne 1 ]; then
    echo "Usage: $0 <fuzz_target>"
    exit 1
fi

# Assign the first argument to the fuzz_target variable
FUZZ_TARGET=$1

# Ensure necessary tools are installed
if ! command -v cargo &> /dev/null; then
    echo "cargo could not be found, please install Rust and Cargo."
    exit 1
fi

if ! command -v llvm-cov &> /dev/null; then
    echo "llvm-cov could not be found, please install LLVM."
    exit 1
fi

if ! command -v rustfilt &> /dev/null; then
    echo "rustfilt could not be found, please install rustfilt."
    exit 1
fi

# Run the cargo fuzz coverage command with the provided fuzz target
cargo +nightly fuzz coverage "$FUZZ_TARGET"

# Define the paths
TARGET_DIR="target/x86_64-unknown-linux-gnu/coverage/x86_64-unknown-linux-gnu/release"
PROF_DATA="fuzz/coverage/$FUZZ_TARGET/coverage.profdata"
OUTPUT_FILE="index.html"

# Check if the coverage data file exists
if [ ! -f "$PROF_DATA" ]; then
    echo "Coverage data file $PROF_DATA not found."
    exit 1
fi

# Generate the coverage report in HTML format
llvm-cov show "$TARGET_DIR/$FUZZ_TARGET" --format=html \
                                         -Xdemangler=rustfilt \
                                         --ignore-filename-regex="\.cargo" \
                                         -instr-profile="$PROF_DATA" \
                                         > "$OUTPUT_FILE"

echo "Coverage report generated as $OUTPUT_FILE"