add fuzz coverage script

Signed-off-by: Prabhat Verma <[email protected]>

Author: Prabhat1308

contrib/generate_fuzz_coverage.sh

@@ -0,0 +1,127 @@
+#!/bin/bash
+set -e
+set -x
+
+# Define the fuzz directory relative to the project root
+FUZZ_DIR="fuzz"
+
+TOOLCHAIN="nightly"
+FEATURES="libfuzzer_fuzz"
+
+# --- Dependencies ---
+echo "Checking/installing dependencies..."
+# cargo-llvm-cov implicitly uses/installs necessary LLVM tools
+rustup +${TOOLCHAIN} component add llvm-tools-preview
+# Check if cargo-llvm-cov is installed, install if not
+if ! cargo +${TOOLCHAIN} --list | grep -q "llvm-cov"; then
+    echo "Installing cargo-llvm-cov..."
+    cargo +${TOOLCHAIN} install cargo-llvm-cov
+fi
+
+# Clean previous builds and coverage artifacts relative to project root
+echo "Cleaning previous build and coverage artifacts..."
+cargo +${TOOLCHAIN} clean
+rm -rf target/llvm-cov-target
+rm -rf target/coverage
+
+echo "Running fuzz targets with cargo-llvm-cov to collect coverage..."
+export RUSTFLAGS="--cfg=fuzzing --cfg=secp256k1_fuzz --cfg=hashes_fuzz"
+
+# Determine host triple dynamically for the --target flag
+HOST_TRIPLE=$(rustc +${TOOLCHAIN} --version --verbose | grep host | cut -d' ' -f2)
+if [ -z "$HOST_TRIPLE" ]; then
+    echo "Error: Could not determine host triple."
+    exit 1
+fi
+echo "Detected host triple: $HOST_TRIPLE"
+
+COMBINED_FEATURES="$FEATURES,lightning/_test_utils,lightning/std,lightning-invoice/std"
+
+# Iterate over target binaries located within the FUZZ_DIR
+for TARGET_PATH in "$FUZZ_DIR"/src/bin/*_target.rs; do
+    FILENAME=$(basename "$TARGET_PATH")
+    TARGET_NAME="${FILENAME%.*}" # Remove .rs extension
+    TARGET_CORPUS_DIR="$FUZZ_DIR/corpus/$TARGET_NAME"
+
+    if [ -d "$TARGET_CORPUS_DIR" ]; then
+        echo "Running cargo llvm-cov for target: $TARGET_NAME with corpus $TARGET_CORPUS_DIR"
+        if ! CARGO_TARGET_DIR=./target cargo +${TOOLCHAIN} llvm-cov run --no-report --manifest-path "$FUZZ_DIR/Cargo.toml" --target "$HOST_TRIPLE" --features "$COMBINED_FEATURES" --bin "$TARGET_NAME" -- "$TARGET_CORPUS_DIR" -runs=1; then
+             echo "Warning: Execution of $TARGET_NAME with cargo-llvm-cov finished with non-zero status."
+        fi
+    else
+        echo "Warning: Corpus directory ($TARGET_CORPUS_DIR) not found for target $TARGET_NAME. Skipping."
+    fi
+done
+
+unset RUSTFLAGS
+
+# Define paths relative to project root
+MERGED_PROFDATA_PATH="target/llvm-cov-target/fuzz.profdata"
+HTML_REPORT_DIR="target/coverage/html"
+mkdir -p "$HTML_REPORT_DIR"
+
+# Find all .profraw files generated by the runs in target/ relative to root
+PROFRAW_FILES=$(find target/llvm-cov-target -name "*.profraw")
+
+if [ -z "$PROFRAW_FILES" ]; then
+    echo "Error: No .profraw files found in target/llvm-cov-target. Cannot generate coverage report."
+    exit 1
+fi
+
+# Merge .profraw files into a single .profdata file
+echo "Merging profraw files..."
+if ! llvm-profdata merge $PROFRAW_FILES -o "$MERGED_PROFDATA_PATH"; then
+    echo "Error: llvm-profdata merge failed."
+    exit 1
+fi
+echo "Merged profile data created at $MERGED_PROFDATA_PATH"
+
+# Identify the instrumented binary files
+echo "Identifying instrumented binaries..."
+declare -a OBJECT_FLAGS
+BINARY_DIR="target/llvm-cov-target/$HOST_TRIPLE/debug"
+
+# Re-iterate over target sources to get names
+for TARGET_PATH in "$FUZZ_DIR"/src/bin/*_target.rs; do
+    FILENAME=$(basename "$TARGET_PATH")
+    TARGET_NAME="${FILENAME%.*}"
+    TARGET_CORPUS_DIR="$FUZZ_DIR/corpus/$TARGET_NAME"
+    BINARY_PATH="$BINARY_DIR/$TARGET_NAME"
+
+    # Check if the corresponding corpus dir existed (meaning the target was likely run)
+    # and if the binary file actually exists
+    if [ -d "$TARGET_CORPUS_DIR" ] && [ -f "$BINARY_PATH" ]; then
+        echo "Found binary for target $TARGET_NAME at $BINARY_PATH"
+        OBJECT_FLAGS+=("-object" "$BINARY_PATH")
+    else
+        echo "Warning: Skipping binary for $TARGET_NAME (corpus dir existed: $([ -d "$TARGET_CORPUS_DIR" ] && echo true || echo false), binary exists: $([ -f "$BINARY_PATH" ] && echo true || echo false))"
+    fi
+done
+
+if [ ${#OBJECT_FLAGS[@]} -eq 0 ]; then
+    echo "Error: No instrumented binaries found in $BINARY_DIR. Cannot generate report."
+    exit 1
+fi
+
+# Generate the HTML report using llvm-cov show
+echo "Generating HTML report using llvm-cov show..."
+IGNORE_REGEX="(/.cargo/|/${FUZZ_DIR}/|/target/|/contrib/|/tests/|/benches/|lightning-invoice/src/convert\.rs|lightning-block-sync/src/lib\.rs|lightning-net-tokio/src/lib\.rs|lightning-persister/src/lib\.rs|lightning-rapid-gossip-sync/src/lib\.rs|lightning-transaction-sync/src/lib\.rs|lightning/src/util/ser\.rs)"
+
+# generate html report
+if ! llvm-cov show \
+    "${OBJECT_FLAGS[@]}" \
+    -instr-profile="$MERGED_PROFDATA_PATH" \
+    -format=html \
+    -output-dir="$HTML_REPORT_DIR" \
+    -ignore-filename-regex="$IGNORE_REGEX" \
+    -show-line-counts-or-regions \
+    -show-instantiations=false; then
+    echo "Error: llvm-cov show command failed."
+    exit 1
+fi
+
+# --- Done ---
+echo "--------------------------------------------------"
+echo "Combined coverage report generation finished."
+echo "Report available at: $HTML_REPORT_DIR/index.html"
+echo "--------------------------------------------------"