1 //! Main evaluator loop and setting up the initial stack frame.
3 use std::convert::TryFrom;
8 use rustc_hir::def_id::DefId;
9 use rustc_middle::ty::{self, layout::LayoutCx, TyCtxt};
10 use rustc_target::abi::LayoutOf;
14 #[derive(Copy, Clone, Debug, PartialEq)]
15 pub enum AlignmentCheck {
16 /// Do not check alignment.
18 /// Check alignment "symbolically", i.e., using only the requested alignment for an allocation and not its real base address.
20 /// Check alignment on the actual physical integer address.
24 /// Configuration needed to spawn a Miri instance.
26 pub struct MiriConfig {
27 /// Determine if validity checking is enabled.
29 /// Determines if Stacked Borrows is enabled.
30 pub stacked_borrows: bool,
31 /// Controls alignment checking.
32 pub check_alignment: AlignmentCheck,
33 /// Determines if communication with the host environment is enabled.
34 pub communicate: bool,
35 /// Determines if memory leaks should be ignored.
36 pub ignore_leaks: bool,
37 /// Environment variables that should always be isolated from the host.
38 pub excluded_env_vars: Vec<String>,
39 /// Command-line arguments passed to the interpreted program.
40 pub args: Vec<String>,
41 /// The seed to use when non-determinism or randomness are required (e.g. ptr-to-int cast, `getrandom()`).
42 pub seed: Option<u64>,
43 /// The stacked borrows pointer id to report about
44 pub tracked_pointer_tag: Option<PtrId>,
45 /// The stacked borrows call ID to report about
46 pub tracked_call_id: Option<CallId>,
47 /// The allocation id to report about.
48 pub tracked_alloc_id: Option<AllocId>,
49 /// Whether to track raw pointers in stacked borrows.
51 /// Determine if data race detection should be enabled
52 pub data_race_detector: bool,
53 /// Rate of spurious failures for compare_exchange_weak atomic operations,
54 /// between 0.0 and 1.0, defaulting to 0.8 (80% chance of failure).
55 pub cmpxchg_weak_failure_rate: f64,
58 impl Default for MiriConfig {
59 fn default() -> MiriConfig {
62 stacked_borrows: true,
63 check_alignment: AlignmentCheck::Int,
66 excluded_env_vars: vec![],
69 tracked_pointer_tag: None,
70 tracked_call_id: None,
71 tracked_alloc_id: None,
73 data_race_detector: true,
74 cmpxchg_weak_failure_rate: 0.8,
79 /// Returns a freshly created `InterpCx`, along with an `MPlaceTy` representing
80 /// the location where the return value of the `start` lang item will be
82 /// Public because this is also used by `priroda`.
83 pub fn create_ecx<'mir, 'tcx: 'mir>(
87 ) -> InterpResult<'tcx, (InterpCx<'mir, 'tcx, Evaluator<'mir, 'tcx>>, MPlaceTy<'tcx, Tag>)> {
88 let param_env = ty::ParamEnv::reveal_all();
89 let layout_cx = LayoutCx { tcx, param_env };
90 let mut ecx = InterpCx::new(
92 rustc_span::source_map::DUMMY_SP,
94 Evaluator::new(config.communicate, config.validate, layout_cx),
95 MemoryExtra::new(&config),
97 // Complete initialization.
98 EnvVars::init(&mut ecx, config.excluded_env_vars)?;
99 MemoryExtra::init_extern_statics(&mut ecx)?;
101 // Setup first stack-frame
102 let main_instance = ty::Instance::mono(tcx, main_id);
103 let main_mir = ecx.load_mir(main_instance.def, None)?;
104 if main_mir.arg_count != 0 {
105 bug!("main function must not take any arguments");
108 let start_id = tcx.lang_items().start_fn().unwrap();
109 let main_ret_ty = tcx.fn_sig(main_id).output();
110 let main_ret_ty = main_ret_ty.no_bound_vars().unwrap();
111 let start_instance = ty::Instance::resolve(
113 ty::ParamEnv::reveal_all(),
115 tcx.mk_substs(::std::iter::once(ty::subst::GenericArg::from(main_ret_ty))),
120 // First argument: pointer to `main()`.
121 let main_ptr = ecx.memory.create_fn_alloc(FnVal::Instance(main_instance));
122 // Second argument (argc): length of `config.args`.
123 let argc = Scalar::from_machine_usize(u64::try_from(config.args.len()).unwrap(), &ecx);
124 // Third argument (`argv`): created from `config.args`.
126 // Put each argument in memory, collect pointers.
127 let mut argvs = Vec::<Scalar<Tag>>::new();
128 for arg in config.args.iter() {
129 // Make space for `0` terminator.
130 let size = u64::try_from(arg.len()).unwrap().checked_add(1).unwrap();
131 let arg_type = tcx.mk_array(tcx.types.u8, size);
132 let arg_place = ecx.allocate(ecx.layout_of(arg_type)?, MiriMemoryKind::Machine.into());
133 ecx.write_os_str_to_c_str(OsStr::new(arg), arg_place.ptr, size)?;
134 argvs.push(arg_place.ptr);
136 // Make an array with all these pointers, in the Miri memory.
138 ecx.layout_of(tcx.mk_array(tcx.mk_imm_ptr(tcx.types.u8), u64::try_from(argvs.len()).unwrap()))?;
139 let argvs_place = ecx.allocate(argvs_layout, MiriMemoryKind::Machine.into());
140 for (idx, arg) in argvs.into_iter().enumerate() {
141 let place = ecx.mplace_field(argvs_place, idx)?;
142 ecx.write_scalar(arg, place.into())?;
144 ecx.memory.mark_immutable(argvs_place.ptr.assert_ptr().alloc_id)?;
145 // A pointer to that place is the 3rd argument for main.
146 let argv = argvs_place.ptr;
147 // Store `argc` and `argv` for macOS `_NSGetArg{c,v}`.
150 ecx.allocate(ecx.machine.layouts.isize, MiriMemoryKind::Machine.into());
151 ecx.write_scalar(argc, argc_place.into())?;
152 ecx.machine.argc = Some(argc_place.ptr);
154 let argv_place = ecx.allocate(
155 ecx.layout_of(tcx.mk_imm_ptr(tcx.types.unit))?,
156 MiriMemoryKind::Machine.into(),
158 ecx.write_scalar(argv, argv_place.into())?;
159 ecx.machine.argv = Some(argv_place.ptr);
161 // Store command line as UTF-16 for Windows `GetCommandLineW`.
163 // Construct a command string with all the aguments.
164 let mut cmd = String::new();
165 for arg in config.args.iter() {
169 cmd.push_str(&*shell_escape::windows::escape(arg.as_str().into()));
171 // Don't forget `0` terminator.
172 cmd.push(std::char::from_u32(0).unwrap());
174 let cmd_utf16: Vec<u16> = cmd.encode_utf16().collect();
175 let cmd_type = tcx.mk_array(tcx.types.u16, u64::try_from(cmd_utf16.len()).unwrap());
176 let cmd_place = ecx.allocate(ecx.layout_of(cmd_type)?, MiriMemoryKind::Machine.into());
177 ecx.machine.cmd_line = Some(cmd_place.ptr);
178 // Store the UTF-16 string. We just allocated so we know the bounds are fine.
179 for (idx, &c) in cmd_utf16.iter().enumerate() {
180 let place = ecx.mplace_field(cmd_place, idx)?;
181 ecx.write_scalar(Scalar::from_u16(c), place.into())?;
187 // Return place (in static memory so that it does not count as leak).
188 let ret_place = ecx.allocate(ecx.machine.layouts.isize, MiriMemoryKind::Machine.into());
189 // Call start function.
192 &[main_ptr.into(), argc.into(), argv.into()],
193 Some(ret_place.into()),
194 StackPopCleanup::None { cleanup: true },
200 /// Evaluates the main function specified by `main_id`.
201 /// Returns `Some(return_code)` if program executed completed.
202 /// Returns `None` if an evaluation error occured.
203 pub fn eval_main<'tcx>(tcx: TyCtxt<'tcx>, main_id: DefId, config: MiriConfig) -> Option<i64> {
204 // Copy setting before we move `config`.
205 let ignore_leaks = config.ignore_leaks;
207 let (mut ecx, ret_place) = match create_ecx(tcx, main_id, config) {
210 err.print_backtrace();
211 panic!("Miri initialization error: {}", err.kind())
215 // Perform the main execution.
216 let res: InterpResult<'_, i64> = (|| {
219 let info = ecx.preprocess_diagnostics();
220 match ecx.schedule()? {
221 SchedulingAction::ExecuteStep => {
222 assert!(ecx.step()?, "a terminated thread was scheduled for execution");
224 SchedulingAction::ExecuteTimeoutCallback => {
225 assert!(ecx.machine.communicate,
226 "scheduler callbacks require disabled isolation, but the code \
227 that created the callback did not check it");
228 ecx.run_timeout_callback()?;
230 SchedulingAction::ExecuteDtors => {
231 // This will either enable the thread again (so we go back
232 // to `ExecuteStep`), or determine that this thread is done
234 ecx.schedule_next_tls_dtor_for_active_thread()?;
236 SchedulingAction::Stop => {
240 ecx.process_diagnostics(info);
242 let return_code = ecx.read_scalar(ret_place.into())?.check_init()?.to_machine_isize(&ecx)?;
247 EnvVars::cleanup(&mut ecx).unwrap();
249 // Process the result.
253 info!("Additonal static roots: {:?}", ecx.machine.static_roots);
254 let leaks = ecx.memory.leak_report(&ecx.machine.static_roots);
256 tcx.sess.err("the evaluated program leaked memory");
257 // Ignore the provided return code - let the reported error
258 // determine the return code.
264 Err(e) => report_error(&ecx, e),