From f0b72461568b4236ad25338c44cb637bcbce1323 Mon Sep 17 00:00:00 2001
From: Xinhao Yuan <xinhaoyuan@google.com>
Date: Fri, 27 Mar 2026 07:02:48 -0700
Subject: [PATCH] Create a library for the FuzzTest llvm fuzzer wrapper to be
 used outside Bazel.

PiperOrigin-RevId: 890430374
---
 fuzztest/BUILD                  | 16 ++++++++++++++++
 fuzztest/llvm_fuzzer_wrapper.cc |  5 +++++
 2 files changed, 21 insertions(+)

diff --git a/fuzztest/BUILD b/fuzztest/BUILD
index 2cb687d2..068b4621 100644
--- a/fuzztest/BUILD
+++ b/fuzztest/BUILD
@@ -16,6 +16,7 @@
 
 load("@bazel_skylib//rules:common_settings.bzl", "bool_flag")
 load("@rules_cc//cc:cc_library.bzl", "cc_library")
+load("@rules_cc//cc:cc_static_library.bzl", "cc_static_library")
 load("@rules_cc//cc:cc_test.bzl", "cc_test")
 
 package(default_visibility = ["//visibility:public"])
@@ -176,6 +177,21 @@ cc_library(
     alwayslink = True,
 )
 
+# A full self-contained library archive that external llvm fuzzers should link
+# to their fuzz targets to make them compatible with FuzzTest.
+#
+# Note that the library should be linked with
+# `--undefined=fuzztest_llvm_fuzzer_wrapper_link_hook` or `--whole-archive`
+# linker flag, as otherwise the test registration would not work.
+cc_static_library(
+    name = "fuzztest_llvm_fuzzer_static",
+    testonly = True,
+    deps = [
+        ":llvm_fuzzer_main",
+        ":llvm_fuzzer_wrapper",
+    ],
+)
+
 cc_library(
     name = "domain",
     hdrs = ["domain.h"],
diff --git a/fuzztest/llvm_fuzzer_wrapper.cc b/fuzztest/llvm_fuzzer_wrapper.cc
index 64077256..905920ac 100644
--- a/fuzztest/llvm_fuzzer_wrapper.cc
+++ b/fuzztest/llvm_fuzzer_wrapper.cc
@@ -45,6 +45,11 @@ extern "C" size_t LLVMFuzzerCustomCrossOver(const uint8_t* data1, size_t size1,
   exit(-1);
 }
 
+// A dummy symbol to be referenced by the linker flag
+// `--undefined=fuzztest_llvm_fuzzer_wrapper_link_hook` to force this file to be
+// included, otherwise the test registration would not be triggered.
+extern "C" [[maybe_unused]] int fuzztest_llvm_fuzzer_wrapper_link_hook = 42;
+
 std::vector<std::vector<uint8_t>> ReadByteArraysFromDirectory() {
   const std::string flag = absl::GetFlag(FLAGS_llvm_fuzzer_wrapper_corpus_dir);
   if (flag.empty()) return {};