1 //! Main evaluator loop and setting up the initial stack frame.
3 use std::convert::TryFrom;
6 use rand::rngs::StdRng;
10 use rustc_hir::def_id::DefId;
11 use rustc_middle::ty::{self, layout::LayoutCx, TyCtxt};
12 use rustc_target::abi::LayoutOf;
16 #[derive(Copy, Clone, Debug, PartialEq)]
17 pub enum AlignmentCheck {
18 /// Do not check alignment.
20 /// Check alignment "symbolically", i.e., using only the requested alignment for an allocation and not its real base address.
22 /// Check alignment on the actual physical integer address.
26 /// Configuration needed to spawn a Miri instance.
28 pub struct MiriConfig {
29 /// Determine if validity checking is enabled.
31 /// Determines if Stacked Borrows is enabled.
32 pub stacked_borrows: bool,
33 /// Controls alignment checking.
34 pub check_alignment: AlignmentCheck,
35 /// Determines if communication with the host environment is enabled.
36 pub communicate: bool,
37 /// Determines if memory leaks should be ignored.
38 pub ignore_leaks: bool,
39 /// Environment variables that should always be isolated from the host.
40 pub excluded_env_vars: Vec<String>,
41 /// Command-line arguments passed to the interpreted program.
42 pub args: Vec<String>,
43 /// The seed to use when non-determinism or randomness are required (e.g. ptr-to-int cast, `getrandom()`).
44 pub seed: Option<u64>,
45 /// The stacked borrows pointer id to report about
46 pub tracked_pointer_tag: Option<PtrId>,
47 /// The stacked borrows call ID to report about
48 pub tracked_call_id: Option<CallId>,
49 /// The allocation id to report about.
50 pub tracked_alloc_id: Option<AllocId>,
53 impl Default for MiriConfig {
54 fn default() -> MiriConfig {
57 stacked_borrows: true,
58 check_alignment: AlignmentCheck::Int,
61 excluded_env_vars: vec![],
64 tracked_pointer_tag: None,
65 tracked_call_id: None,
66 tracked_alloc_id: None,
71 /// Returns a freshly created `InterpCx`, along with an `MPlaceTy` representing
72 /// the location where the return value of the `start` lang item will be
74 /// Public because this is also used by `priroda`.
75 pub fn create_ecx<'mir, 'tcx: 'mir>(
79 ) -> InterpResult<'tcx, (InterpCx<'mir, 'tcx, Evaluator<'mir, 'tcx>>, MPlaceTy<'tcx, Tag>)> {
80 let param_env = ty::ParamEnv::reveal_all();
81 let layout_cx = LayoutCx { tcx, param_env };
82 let mut ecx = InterpCx::new(
84 rustc_span::source_map::DUMMY_SP,
86 Evaluator::new(config.communicate, config.validate, layout_cx),
88 StdRng::seed_from_u64(config.seed.unwrap_or(0)),
89 config.stacked_borrows,
90 config.tracked_pointer_tag,
91 config.tracked_call_id,
92 config.tracked_alloc_id,
93 config.check_alignment,
96 // Complete initialization.
97 EnvVars::init(&mut ecx, config.excluded_env_vars)?;
98 MemoryExtra::init_extern_statics(&mut ecx)?;
100 // Setup first stack-frame
101 let main_instance = ty::Instance::mono(tcx, main_id);
102 let main_mir = ecx.load_mir(main_instance.def, None)?;
103 if main_mir.arg_count != 0 {
104 bug!("main function must not take any arguments");
107 let start_id = tcx.lang_items().start_fn().unwrap();
108 let main_ret_ty = tcx.fn_sig(main_id).output();
109 let main_ret_ty = main_ret_ty.no_bound_vars().unwrap();
110 let start_instance = ty::Instance::resolve(
112 ty::ParamEnv::reveal_all(),
114 tcx.mk_substs(::std::iter::once(ty::subst::GenericArg::from(main_ret_ty))),
119 // First argument: pointer to `main()`.
120 let main_ptr = ecx.memory.create_fn_alloc(FnVal::Instance(main_instance));
121 // Second argument (argc): length of `config.args`.
122 let argc = Scalar::from_machine_usize(u64::try_from(config.args.len()).unwrap(), &ecx);
123 // Third argument (`argv`): created from `config.args`.
125 // Put each argument in memory, collect pointers.
126 let mut argvs = Vec::<Scalar<Tag>>::new();
127 for arg in config.args.iter() {
128 // Make space for `0` terminator.
129 let size = u64::try_from(arg.len()).unwrap().checked_add(1).unwrap();
130 let arg_type = tcx.mk_array(tcx.types.u8, size);
131 let arg_place = ecx.allocate(ecx.layout_of(arg_type)?, MiriMemoryKind::Machine.into());
132 ecx.write_os_str_to_c_str(OsStr::new(arg), arg_place.ptr, size)?;
133 argvs.push(arg_place.ptr);
135 // Make an array with all these pointers, in the Miri memory.
137 ecx.layout_of(tcx.mk_array(tcx.mk_imm_ptr(tcx.types.u8), u64::try_from(argvs.len()).unwrap()))?;
138 let argvs_place = ecx.allocate(argvs_layout, MiriMemoryKind::Machine.into());
139 for (idx, arg) in argvs.into_iter().enumerate() {
140 let place = ecx.mplace_field(argvs_place, idx)?;
141 ecx.write_scalar(arg, place.into())?;
143 ecx.memory.mark_immutable(argvs_place.ptr.assert_ptr().alloc_id)?;
144 // A pointer to that place is the 3rd argument for main.
145 let argv = argvs_place.ptr;
146 // Store `argc` and `argv` for macOS `_NSGetArg{c,v}`.
149 ecx.allocate(ecx.machine.layouts.isize, MiriMemoryKind::Machine.into());
150 ecx.write_scalar(argc, argc_place.into())?;
151 ecx.machine.argc = Some(argc_place.ptr);
153 let argv_place = ecx.allocate(
154 ecx.layout_of(tcx.mk_imm_ptr(tcx.types.unit))?,
155 MiriMemoryKind::Machine.into(),
157 ecx.write_scalar(argv, argv_place.into())?;
158 ecx.machine.argv = Some(argv_place.ptr);
160 // Store command line as UTF-16 for Windows `GetCommandLineW`.
162 // Construct a command string with all the aguments.
163 let mut cmd = String::new();
164 for arg in config.args.iter() {
168 cmd.push_str(&*shell_escape::windows::escape(arg.as_str().into()));
170 // Don't forget `0` terminator.
171 cmd.push(std::char::from_u32(0).unwrap());
173 let cmd_utf16: Vec<u16> = cmd.encode_utf16().collect();
174 let cmd_type = tcx.mk_array(tcx.types.u16, u64::try_from(cmd_utf16.len()).unwrap());
175 let cmd_place = ecx.allocate(ecx.layout_of(cmd_type)?, MiriMemoryKind::Machine.into());
176 ecx.machine.cmd_line = Some(cmd_place.ptr);
177 // Store the UTF-16 string. We just allocated so we know the bounds are fine.
178 for (idx, &c) in cmd_utf16.iter().enumerate() {
179 let place = ecx.mplace_field(cmd_place, idx)?;
180 ecx.write_scalar(Scalar::from_u16(c), place.into())?;
186 // Return place (in static memory so that it does not count as leak).
187 let ret_place = ecx.allocate(ecx.machine.layouts.isize, MiriMemoryKind::Machine.into());
188 // Call start function.
191 &[main_ptr.into(), argc.into(), argv.into()],
192 Some(ret_place.into()),
193 StackPopCleanup::None { cleanup: true },
196 // Set the last_error to 0
197 let errno_layout = ecx.machine.layouts.u32;
198 let errno_place = ecx.allocate(errno_layout, MiriMemoryKind::Machine.into());
199 ecx.write_scalar(Scalar::from_u32(0), errno_place.into())?;
200 ecx.machine.last_error = Some(errno_place);
205 /// Evaluates the main function specified by `main_id`.
206 /// Returns `Some(return_code)` if program executed completed.
207 /// Returns `None` if an evaluation error occured.
208 pub fn eval_main<'tcx>(tcx: TyCtxt<'tcx>, main_id: DefId, config: MiriConfig) -> Option<i64> {
209 // Copy setting before we move `config`.
210 let ignore_leaks = config.ignore_leaks;
212 let (mut ecx, ret_place) = match create_ecx(tcx, main_id, config) {
215 err.print_backtrace();
216 panic!("Miri initialization error: {}", err.kind)
220 // Perform the main execution.
221 let res: InterpResult<'_, i64> = (|| {
224 let info = ecx.preprocess_diagnostics();
225 match ecx.schedule()? {
226 SchedulingAction::ExecuteStep => {
227 assert!(ecx.step()?, "a terminated thread was scheduled for execution");
229 SchedulingAction::ExecuteTimeoutCallback => {
230 assert!(ecx.machine.communicate,
231 "scheduler callbacks require disabled isolation, but the code \
232 that created the callback did not check it");
233 ecx.run_timeout_callback()?;
235 SchedulingAction::ExecuteDtors => {
236 // This will either enable the thread again (so we go back
237 // to `ExecuteStep`), or determine that this thread is done
239 ecx.schedule_next_tls_dtor_for_active_thread()?;
241 SchedulingAction::Stop => {
245 ecx.process_diagnostics(info);
247 let return_code = ecx.read_scalar(ret_place.into())?.check_init()?.to_machine_isize(&ecx)?;
252 EnvVars::cleanup(&mut ecx).unwrap();
254 // Process the result.
258 info!("Additonal static roots: {:?}", ecx.machine.static_roots);
259 let leaks = ecx.memory.leak_report(&ecx.machine.static_roots);
261 tcx.sess.err("the evaluated program leaked memory");
262 // Ignore the provided return code - let the reported error
263 // determine the return code.
269 Err(e) => report_error(&ecx, e),