1 //! Main evaluator loop and setting up the initial stack frame.
5 use rand::rngs::StdRng;
8 use rustc::hir::def_id::DefId;
9 use rustc::ty::layout::{LayoutOf, Size};
10 use rustc::ty::{self, TyCtxt};
14 /// Configuration needed to spawn a Miri instance.
16 pub struct MiriConfig {
17 /// Determine if validity checking and Stacked Borrows are enabled.
19 /// Determines if communication with the host environment is enabled.
20 pub communicate: bool,
21 /// Determines if memory leaks should be ignored.
22 pub ignore_leaks: bool,
23 /// Environment variables that should always be isolated from the host.
24 pub excluded_env_vars: Vec<String>,
25 /// Command-line arguments passed to the interpreted program.
26 pub args: Vec<String>,
27 /// The seed to use when non-determinism or randomness are required (e.g. ptr-to-int cast, `getrandom()`).
28 pub seed: Option<u64>,
29 /// The stacked borrow id to report about
30 pub tracked_pointer_tag: Option<PtrId>,
33 /// Details of premature program termination.
34 pub enum TerminationInfo {
36 PoppedTrackedPointerTag(Item),
40 /// Returns a freshly created `InterpCx`, along with an `MPlaceTy` representing
41 /// the location where the return value of the `start` lang item will be
43 /// Public because this is also used by `priroda`.
44 pub fn create_ecx<'mir, 'tcx: 'mir>(
48 ) -> InterpResult<'tcx, (InterpCx<'mir, 'tcx, Evaluator<'tcx>>, MPlaceTy<'tcx, Tag>)> {
49 let mut ecx = InterpCx::new(
50 tcx.at(syntax::source_map::DUMMY_SP),
51 ty::ParamEnv::reveal_all(),
52 Evaluator::new(config.communicate),
54 StdRng::seed_from_u64(config.seed.unwrap_or(0)),
56 config.tracked_pointer_tag,
59 // Complete initialization.
60 EnvVars::init(&mut ecx, config.excluded_env_vars);
62 // Setup first stack-frame
63 let main_instance = ty::Instance::mono(tcx, main_id);
64 let main_mir = ecx.load_mir(main_instance.def, None)?;
66 if !main_mir.return_ty().is_unit() || main_mir.arg_count != 0 {
67 throw_unsup_format!("miri does not support main functions without `fn()` type signatures");
70 let start_id = tcx.lang_items().start_fn().unwrap();
71 let main_ret_ty = tcx.fn_sig(main_id).output();
72 let main_ret_ty = main_ret_ty.no_bound_vars().unwrap();
73 let start_instance = ty::Instance::resolve(
75 ty::ParamEnv::reveal_all(),
77 tcx.mk_substs(::std::iter::once(ty::subst::GenericArg::from(main_ret_ty))),
81 // First argument: pointer to `main()`.
82 let main_ptr = ecx.memory.create_fn_alloc(FnVal::Instance(main_instance));
83 // Second argument (argc): length of `config.args`.
84 let argc = Scalar::from_uint(config.args.len() as u128, ecx.pointer_size());
85 // Third argument (`argv`): created from `config.args`.
87 // Put each argument in memory, collect pointers.
88 let mut argvs = Vec::<Scalar<Tag>>::new();
89 for arg in config.args.iter() {
90 // Make space for `0` terminator.
91 let size = arg.len() as u64 + 1;
92 let arg_type = tcx.mk_array(tcx.types.u8, size);
93 let arg_place = ecx.allocate(ecx.layout_of(arg_type)?, MiriMemoryKind::Env.into());
94 ecx.write_os_str_to_c_str(OsStr::new(arg), arg_place.ptr, size)?;
95 argvs.push(arg_place.ptr);
97 // Make an array with all these pointers, in the Miri memory.
99 ecx.layout_of(tcx.mk_array(tcx.mk_imm_ptr(tcx.types.u8), argvs.len() as u64))?;
100 let argvs_place = ecx.allocate(argvs_layout, MiriMemoryKind::Env.into());
101 for (idx, arg) in argvs.into_iter().enumerate() {
102 let place = ecx.mplace_field(argvs_place, idx as u64)?;
103 ecx.write_scalar(arg, place.into())?;
105 ecx.memory.mark_immutable(argvs_place.ptr.assert_ptr().alloc_id)?;
106 // A pointer to that place is the 3rd argument for main.
107 let argv = argvs_place.ptr;
108 // Store `argc` and `argv` for macOS `_NSGetArg{c,v}`.
111 ecx.allocate(ecx.layout_of(tcx.types.isize)?, MiriMemoryKind::Env.into());
112 ecx.write_scalar(argc, argc_place.into())?;
113 ecx.machine.argc = Some(argc_place.ptr);
115 let argv_place = ecx.allocate(
116 ecx.layout_of(tcx.mk_imm_ptr(tcx.types.unit))?,
117 MiriMemoryKind::Env.into(),
119 ecx.write_scalar(argv, argv_place.into())?;
120 ecx.machine.argv = Some(argv_place.ptr);
122 // Store command line as UTF-16 for Windows `GetCommandLineW`.
124 // Construct a command string with all the aguments.
125 let mut cmd = String::new();
126 for arg in config.args.iter() {
130 cmd.push_str(&*shell_escape::windows::escape(arg.as_str().into()));
132 // Don't forget `0` terminator.
133 cmd.push(std::char::from_u32(0).unwrap());
135 let cmd_utf16: Vec<u16> = cmd.encode_utf16().collect();
136 let cmd_type = tcx.mk_array(tcx.types.u16, cmd_utf16.len() as u64);
137 let cmd_place = ecx.allocate(ecx.layout_of(cmd_type)?, MiriMemoryKind::Env.into());
138 ecx.machine.cmd_line = Some(cmd_place.ptr);
139 // Store the UTF-16 string. We just allocated so we know the bounds are fine.
140 let char_size = Size::from_bytes(2);
141 for (idx, &c) in cmd_utf16.iter().enumerate() {
142 let place = ecx.mplace_field(cmd_place, idx as u64)?;
143 ecx.write_scalar(Scalar::from_uint(c, char_size), place.into())?;
149 // Return place (in static memory so that it does not count as leak).
150 let ret_place = ecx.allocate(ecx.layout_of(tcx.types.isize)?, MiriMemoryKind::Env.into());
151 // Call start function.
154 &[main_ptr.into(), argc.into(), argv.into()],
155 Some(ret_place.into()),
156 StackPopCleanup::None { cleanup: true },
159 // Set the last_error to 0
160 let errno_layout = ecx.layout_of(tcx.types.u32)?;
161 let errno_place = ecx.allocate(errno_layout, MiriMemoryKind::Env.into());
162 ecx.write_scalar(Scalar::from_u32(0), errno_place.into())?;
163 ecx.machine.last_error = Some(errno_place);
168 /// Evaluates the main function specified by `main_id`.
169 /// Returns `Some(return_code)` if program executed completed.
170 /// Returns `None` if an evaluation error occured.
171 pub fn eval_main<'tcx>(tcx: TyCtxt<'tcx>, main_id: DefId, config: MiriConfig) -> Option<i64> {
172 // FIXME: We always ignore leaks on some platforms where we do not
173 // correctly implement TLS destructors.
174 let target_os = tcx.sess.target.target.target_os.to_lowercase();
175 let ignore_leaks = config.ignore_leaks || target_os == "windows" || target_os == "macos";
177 let (mut ecx, ret_place) = match create_ecx(tcx, main_id, config) {
180 err.print_backtrace();
181 panic!("Miri initialziation error: {}", err.kind)
185 // Perform the main execution.
186 let res: InterpResult<'_, i64> = (|| {
188 // Read the return code pointer *before* we run TLS destructors, to assert
189 // that it was written to by the time that `start` lang item returned.
190 let return_code = ecx.read_scalar(ret_place.into())?.not_undef()?.to_machine_isize(&ecx)?;
191 ecx.run_tls_dtors()?;
195 // Process the result.
199 let leaks = ecx.memory.leak_report();
201 tcx.sess.err("the evaluated program leaked memory");
202 // Ignore the provided return code - let the reported error
203 // determine the return code.
207 return Some(return_code);
210 // Special treatment for some error kinds
211 let msg = match e.kind {
212 InterpError::MachineStop(ref info) => {
214 .downcast_ref::<TerminationInfo>()
215 .expect("invalid MachineStop payload");
217 TerminationInfo::Exit(code) => return Some(*code),
218 TerminationInfo::PoppedTrackedPointerTag(item) =>
219 format!("popped tracked tag for item {:?}", item),
220 TerminationInfo::Abort =>
221 format!("the evaluated program aborted execution"),
224 err_unsup!(NoMirFor(..)) => format!(
225 "{}. Did you set `MIRI_SYSROOT` to a Miri-enabled sysroot? You can prepare one with `cargo miri setup`.",
228 InterpError::InvalidProgram(_) =>
229 bug!("This error should be impossible in Miri: {}", e),
233 if let Some(frame) = ecx.stack().last() {
234 let span = frame.current_source_info().unwrap().span;
236 let msg = format!("Miri evaluation error: {}", msg);
237 let mut err = ecx.tcx.sess.struct_span_err(span, msg.as_str());
238 let frames = ecx.generate_stacktrace(None);
239 err.span_label(span, msg);
240 // We iterate with indices because we need to look at the next frame (the caller).
241 for idx in 0..frames.len() {
242 let frame_info = &frames[idx];
243 let call_site_is_local = frames
245 .map_or(false, |caller_info| caller_info.instance.def_id().is_local());
246 if call_site_is_local {
247 err.span_note(frame_info.call_site, &frame_info.to_string());
249 err.note(&frame_info.to_string());
254 ecx.tcx.sess.err(&msg);
257 for (i, frame) in ecx.stack().iter().enumerate() {
258 trace!("-------------------");
259 trace!("Frame {}", i);
260 trace!(" return: {:?}", frame.return_place.map(|p| *p));
261 for (i, local) in frame.locals.iter().enumerate() {
262 trace!(" local {}: {:?}", i, local.value);
265 // Let the reported error determine the return code.