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Merged
merged 2 commits into from
Feb 12, 2025
Merged

fuzzer: write inputs to shared memory before running #22862

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31c1320
ZigLLVMTargetMachineEmitToFile: schedule sancov pass depending on mode
andrewrk Feb 11, 2025
d789f1e
fuzzer: write inputs to shared memory before running
andrewrk Feb 11, 2025
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22 changes: 16 additions & 6 deletions lib/compiler/test_runner.zig
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Original file line number Diff line number Diff line change
Expand Up @@ -150,6 +150,7 @@ fn mainServer() !void {
try server.serveU64Message(.fuzz_start_addr, entry_addr);
defer if (testing.allocator_instance.deinit() == .leak) std.process.exit(1);
is_fuzz_test = false;
fuzzer_set_name(test_fn.name.ptr, test_fn.name.len);
test_fn.func() catch |err| switch (err) {
error.SkipZigTest => return,
else => {
Expand Down Expand Up @@ -341,12 +342,15 @@ const FuzzerSlice = extern struct {

var is_fuzz_test: bool = undefined;

extern fn fuzzer_start(testOne: *const fn ([*]const u8, usize) callconv(.C) void) void;
extern fn fuzzer_set_name(name_ptr: [*]const u8, name_len: usize) void;
extern fn fuzzer_init(cache_dir: FuzzerSlice) void;
extern fn fuzzer_init_corpus_elem(input_ptr: [*]const u8, input_len: usize) void;
extern fn fuzzer_start(testOne: *const fn ([*]const u8, usize) callconv(.C) void) void;
extern fn fuzzer_coverage_id() u64;

pub fn fuzz(
comptime testOne: fn ([]const u8) anyerror!void,
context: anytype,
comptime testOne: fn (context: @TypeOf(context), []const u8) anyerror!void,
options: testing.FuzzInputOptions,
) anyerror!void {
// Prevent this function from confusing the fuzzer by omitting its own code
Expand All @@ -371,12 +375,14 @@ pub fn fuzz(
// our standard unit test checks such as memory leaks, and interaction with
// error logs.
const global = struct {
var ctx: @TypeOf(context) = undefined;

fn fuzzer_one(input_ptr: [*]const u8, input_len: usize) callconv(.C) void {
@disableInstrumentation();
testing.allocator_instance = .{};
defer if (testing.allocator_instance.deinit() == .leak) std.process.exit(1);
log_err_count = 0;
testOne(input_ptr[0..input_len]) catch |err| switch (err) {
testOne(ctx, input_ptr[0..input_len]) catch |err| switch (err) {
error.SkipZigTest => return,
else => {
std.debug.lockStdErr();
Expand All @@ -395,18 +401,22 @@ pub fn fuzz(
if (builtin.fuzz) {
const prev_allocator_state = testing.allocator_instance;
testing.allocator_instance = .{};
defer testing.allocator_instance = prev_allocator_state;

for (options.corpus) |elem| fuzzer_init_corpus_elem(elem.ptr, elem.len);

global.ctx = context;
fuzzer_start(&global.fuzzer_one);
testing.allocator_instance = prev_allocator_state;
return;
}

// When the unit test executable is not built in fuzz mode, only run the
// provided corpus.
for (options.corpus) |input| {
try testOne(input);
try testOne(context, input);
}

// In case there is no provided corpus, also use an empty
// string as a smoke test.
try testOne("");
try testOne(context, "");
}
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