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 {
39 /// Returns a freshly created `InterpCx`, along with an `MPlaceTy` representing
40 /// the location where the return value of the `start` lang item will be
42 /// Public because this is also used by `priroda`.
43 pub fn create_ecx<'mir, 'tcx: 'mir>(
47 ) -> InterpResult<'tcx, (InterpCx<'mir, 'tcx, Evaluator<'tcx>>, MPlaceTy<'tcx, Tag>)> {
48 let mut ecx = InterpCx::new(
49 tcx.at(rustc_span::source_map::DUMMY_SP),
50 ty::ParamEnv::reveal_all(),
51 Evaluator::new(config.communicate),
53 StdRng::seed_from_u64(config.seed.unwrap_or(0)),
55 config.tracked_pointer_tag,
58 // Complete initialization.
59 EnvVars::init(&mut ecx, config.excluded_env_vars);
61 // Setup first stack-frame
62 let main_instance = ty::Instance::mono(tcx, main_id);
63 let main_mir = ecx.load_mir(main_instance.def, None)?;
64 if main_mir.arg_count != 0 {
65 bug!("main function must not take any arguments");
68 let start_id = tcx.lang_items().start_fn().unwrap();
69 let main_ret_ty = tcx.fn_sig(main_id).output();
70 let main_ret_ty = main_ret_ty.no_bound_vars().unwrap();
71 let start_instance = ty::Instance::resolve(
73 ty::ParamEnv::reveal_all(),
75 tcx.mk_substs(::std::iter::once(ty::subst::GenericArg::from(main_ret_ty))),
79 // First argument: pointer to `main()`.
80 let main_ptr = ecx.memory.create_fn_alloc(FnVal::Instance(main_instance));
81 // Second argument (argc): length of `config.args`.
82 let argc = Scalar::from_uint(config.args.len() as u128, ecx.pointer_size());
83 // Third argument (`argv`): created from `config.args`.
85 // Put each argument in memory, collect pointers.
86 let mut argvs = Vec::<Scalar<Tag>>::new();
87 for arg in config.args.iter() {
88 // Make space for `0` terminator.
89 let size = arg.len() as u64 + 1;
90 let arg_type = tcx.mk_array(tcx.types.u8, size);
91 let arg_place = ecx.allocate(ecx.layout_of(arg_type)?, MiriMemoryKind::Env.into());
92 ecx.write_os_str_to_c_str(OsStr::new(arg), arg_place.ptr, size)?;
93 argvs.push(arg_place.ptr);
95 // Make an array with all these pointers, in the Miri memory.
97 ecx.layout_of(tcx.mk_array(tcx.mk_imm_ptr(tcx.types.u8), argvs.len() as u64))?;
98 let argvs_place = ecx.allocate(argvs_layout, MiriMemoryKind::Env.into());
99 for (idx, arg) in argvs.into_iter().enumerate() {
100 let place = ecx.mplace_field(argvs_place, idx as u64)?;
101 ecx.write_scalar(arg, place.into())?;
103 ecx.memory.mark_immutable(argvs_place.ptr.assert_ptr().alloc_id)?;
104 // A pointer to that place is the 3rd argument for main.
105 let argv = argvs_place.ptr;
106 // Store `argc` and `argv` for macOS `_NSGetArg{c,v}`.
109 ecx.allocate(ecx.layout_of(tcx.types.isize)?, MiriMemoryKind::Env.into());
110 ecx.write_scalar(argc, argc_place.into())?;
111 ecx.machine.argc = Some(argc_place.ptr);
113 let argv_place = ecx.allocate(
114 ecx.layout_of(tcx.mk_imm_ptr(tcx.types.unit))?,
115 MiriMemoryKind::Env.into(),
117 ecx.write_scalar(argv, argv_place.into())?;
118 ecx.machine.argv = Some(argv_place.ptr);
120 // Store command line as UTF-16 for Windows `GetCommandLineW`.
122 // Construct a command string with all the aguments.
123 let mut cmd = String::new();
124 for arg in config.args.iter() {
128 cmd.push_str(&*shell_escape::windows::escape(arg.as_str().into()));
130 // Don't forget `0` terminator.
131 cmd.push(std::char::from_u32(0).unwrap());
133 let cmd_utf16: Vec<u16> = cmd.encode_utf16().collect();
134 let cmd_type = tcx.mk_array(tcx.types.u16, cmd_utf16.len() as u64);
135 let cmd_place = ecx.allocate(ecx.layout_of(cmd_type)?, MiriMemoryKind::Env.into());
136 ecx.machine.cmd_line = Some(cmd_place.ptr);
137 // Store the UTF-16 string. We just allocated so we know the bounds are fine.
138 let char_size = Size::from_bytes(2);
139 for (idx, &c) in cmd_utf16.iter().enumerate() {
140 let place = ecx.mplace_field(cmd_place, idx as u64)?;
141 ecx.write_scalar(Scalar::from_uint(c, char_size), place.into())?;
147 // Return place (in static memory so that it does not count as leak).
148 let ret_place = ecx.allocate(ecx.layout_of(tcx.types.isize)?, MiriMemoryKind::Env.into());
149 // Call start function.
152 &[main_ptr.into(), argc.into(), argv.into()],
153 Some(ret_place.into()),
154 StackPopCleanup::None { cleanup: true },
157 // Set the last_error to 0
158 let errno_layout = ecx.layout_of(tcx.types.u32)?;
159 let errno_place = ecx.allocate(errno_layout, MiriMemoryKind::Env.into());
160 ecx.write_scalar(Scalar::from_u32(0), errno_place.into())?;
161 ecx.machine.last_error = Some(errno_place);
166 /// Evaluates the main function specified by `main_id`.
167 /// Returns `Some(return_code)` if program executed completed.
168 /// Returns `None` if an evaluation error occured.
169 pub fn eval_main<'tcx>(tcx: TyCtxt<'tcx>, main_id: DefId, config: MiriConfig) -> Option<i64> {
170 // FIXME: We always ignore leaks on some platforms where we do not
171 // correctly implement TLS destructors.
172 let target_os = tcx.sess.target.target.target_os.to_lowercase();
173 let ignore_leaks = config.ignore_leaks || target_os == "windows" || target_os == "macos";
175 let (mut ecx, ret_place) = match create_ecx(tcx, main_id, config) {
178 err.print_backtrace();
179 panic!("Miri initialziation error: {}", err.kind)
183 // Perform the main execution.
184 let res: InterpResult<'_, i64> = (|| {
186 ecx.process_errors();
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.
209 Err(e) => report_err(&ecx, e),