ci: add daily amd64 clang fuzz ci check to .drone.yml

.drone.yml

@@ -1,3 +1,18 @@
+---
+kind: pipeline
+type: docker
+name: daily — amd64 — clang
+trigger:
+  branch:
+  - main
+
+steps:
+- name: fuzz
+  image: amd64_clang_fuzz:latest
+  pull: if-not-exists
+  commands:
+    - ./tools/ci/amd64/clang/fuzz.sh
+
 ---
 kind: pipeline
 type: exec

tools/ci/amd64/clang/fuzz.sh

@@ -0,0 +1,57 @@
+#!/bin/bash
+
+set -e
+cd $(git rev-parse --show-toplevel)/
+# rm -rf ./build
+
+export CC=$(which afl-clang-lto)
+export CXX=$(which afl-clang-lto++)
+export AR=$(which llvm-ar)
+export RANLIB=$(which llvm-ranlib)
+export AS=$(which llvm-as)
+
+conan build . \
+    -c tools.system.package_manager:mode=install \
+    -c tools.cmake.cmaketoolchain:generator=Ninja \
+    -c tools.build:compiler_executables='{"c": "afl-clang-lto", "cpp": "afl-clang-lto++"}' \
+    -s build_type=Release \
+    -s compiler=clang \
+    -s compiler.version=20 \
+    -s compiler.libcxx=libc++ \
+    -o use_mold=True \
+    --build=missing \
+    --build=missing
+
+fuzz_test_count=$(find ./build -type f -name '*_fuzz' -executable | wc -l)
+total_fuzz_time=60 # in seconds
+
+time_per_fuzz=$((total_fuzz_time / fuzz_test_count))
+
+echo "Fuzz test count: ${fuzz_test_count}"
+echo "Total fuzz time: ${total_fuzz_time}"
+echo "Time per fuzz: ${time_per_fuzz}"
+
+export AFL_SKIP_CPUFREQ=1
+export AFL_NO_UI=1
+
+for fuzz_name in $(find ./build -type f -name '*_fuzz' -executable); do
+    base_name=$(basename $fuzz_name)
+    out_path="/fuzz/${base_name}_out"
+    in_path="/fuzz/${base_name}_in"
+
+    echo "Running ${fuzz_name} for ${time_per_fuzz} seconds..."
+    echo "base_name: ${base_name}"
+    echo "out_path: ${out_path}"
+    echo "in_path: ${in_path}"
+
+    if [[ ! -e $dir ]]; then
+        echo "No directories detected for ${base_name}"
+        echo "Creating dummy files..."
+        mkdir -p ${in_path}
+        mkdir -p ${out_path}
+
+        echo "0" > ${in_path}/a
+    fi
+
+    afl-fuzz -V $time_per_fuzz -i $in_path -o $out_path -- $fuzz_name
+done