1 //! Main evaluator loop and setting up the initial stack frame.
3 use rand::rngs::StdRng;
6 use rustc::hir::def_id::DefId;
7 use rustc::ty::layout::{LayoutOf, Size};
8 use rustc::ty::{self, TyCtxt};
9 use syntax::source_map::DUMMY_SP;
12 EnvVars, Evaluator, FnVal, HelpersEvalContextExt, InterpCx, InterpError,
13 InterpResult, MemoryExtra, MiriMemoryKind, Pointer, Scalar, StackPopCleanup, Tag,
17 /// Configuration needed to spawn a Miri instance.
19 pub struct MiriConfig {
20 /// Determine if validity checking and Stacked Borrows are enabled.
22 /// Determines if communication with the host environment is enabled.
23 pub communicate: bool,
24 /// Environment variables that should always be isolated from the host.
25 pub excluded_env_vars: Vec<String>,
26 /// Command-line arguments passed to the interpreted program.
27 pub args: Vec<String>,
28 /// The seed to use when non-determinism or randomness are required (e.g. ptr-to-int cast, `getrandom()`).
29 pub seed: Option<u64>,
33 pub fn create_ecx<'mir, 'tcx: 'mir>(
37 ) -> InterpResult<'tcx, InterpCx<'mir, 'tcx, Evaluator<'tcx>>> {
38 let mut ecx = InterpCx::new(
39 tcx.at(syntax::source_map::DUMMY_SP),
40 ty::ParamEnv::reveal_all(),
41 Evaluator::new(config.communicate),
42 MemoryExtra::new(StdRng::seed_from_u64(config.seed.unwrap_or(0)), config.validate),
44 // Complete initialization.
45 EnvVars::init(&mut ecx, config.excluded_env_vars);
47 // Setup first stack-frame
48 let main_instance = ty::Instance::mono(tcx, main_id);
49 let main_mir = ecx.load_mir(main_instance.def, None)?;
51 if !main_mir.return_ty().is_unit() || main_mir.arg_count != 0 {
52 throw_unsup_format!("miri does not support main functions without `fn()` type signatures");
55 let start_id = tcx.lang_items().start_fn().unwrap();
56 let main_ret_ty = tcx.fn_sig(main_id).output();
57 let main_ret_ty = main_ret_ty.no_bound_vars().unwrap();
58 let start_instance = ty::Instance::resolve(
60 ty::ParamEnv::reveal_all(),
62 tcx.mk_substs(::std::iter::once(ty::subst::GenericArg::from(main_ret_ty))),
65 let start_mir = ecx.load_mir(start_instance.def, None)?;
67 if start_mir.arg_count != 3 {
69 "'start' lang item should have three arguments, but has {}",
74 // Return value (in static memory so that it does not count as leak).
75 let ret = ecx.layout_of(start_mir.return_ty())?;
76 let ret_ptr = ecx.allocate(ret, MiriMemoryKind::Static.into());
78 // Push our stack frame.
81 // There is no call site.
85 StackPopCleanup::None { cleanup: true },
88 let mut args = ecx.frame().body.args_iter();
90 // First argument: pointer to `main()`.
93 .create_fn_alloc(FnVal::Instance(main_instance));
94 let dest = ecx.local_place(args.next().unwrap())?;
95 ecx.write_scalar(Scalar::Ptr(main_ptr), dest)?;
97 // Second argument (argc): `1`.
98 let dest = ecx.local_place(args.next().unwrap())?;
99 let argc = Scalar::from_uint(config.args.len() as u128, dest.layout.size);
100 ecx.write_scalar(argc, dest)?;
101 // Store argc for macOS's `_NSGetArgc`.
103 let argc_place = ecx.allocate(dest.layout, MiriMemoryKind::Env.into());
104 ecx.write_scalar(argc, argc_place.into())?;
105 ecx.machine.argc = Some(argc_place.ptr);
108 // Third argument (`argv`): created from `config.args`.
109 let dest = ecx.local_place(args.next().unwrap())?;
110 // For Windows, construct a command string with all the aguments.
111 let mut cmd = String::new();
112 for arg in config.args.iter() {
116 cmd.push_str(&*shell_escape::windows::escape(arg.as_str().into()));
118 // Don't forget `0` terminator.
119 cmd.push(std::char::from_u32(0).unwrap());
120 // Collect the pointers to the individual strings.
121 let mut argvs = Vec::<Pointer<Tag>>::new();
122 for arg in config.args {
123 // Add `0` terminator.
124 let mut arg = arg.into_bytes();
128 .allocate_static_bytes(arg.as_slice(), MiriMemoryKind::Static.into()),
131 // Make an array with all these pointers, in the Miri memory.
132 let argvs_layout = ecx.layout_of(
133 tcx.mk_array(tcx.mk_imm_ptr(tcx.types.u8), argvs.len() as u64),
135 let argvs_place = ecx.allocate(argvs_layout, MiriMemoryKind::Env.into());
136 for (idx, arg) in argvs.into_iter().enumerate() {
137 let place = ecx.mplace_field(argvs_place, idx as u64)?;
138 ecx.write_scalar(Scalar::Ptr(arg), place.into())?;
141 .mark_immutable(argvs_place.ptr.assert_ptr().alloc_id)?;
142 // Write a pointer to that place as the argument.
143 let argv = argvs_place.ptr;
144 ecx.write_scalar(argv, dest)?;
145 // Store `argv` for macOS `_NSGetArgv`.
147 let argv_place = ecx.allocate(dest.layout, MiriMemoryKind::Env.into());
148 ecx.write_scalar(argv, argv_place.into())?;
149 ecx.machine.argv = Some(argv_place.ptr);
151 // Store command line as UTF-16 for Windows `GetCommandLineW`.
153 let cmd_utf16: Vec<u16> = cmd.encode_utf16().collect();
154 let cmd_type = tcx.mk_array(tcx.types.u16, cmd_utf16.len() as u64);
155 let cmd_place = ecx.allocate(ecx.layout_of(cmd_type)?, MiriMemoryKind::Env.into());
156 ecx.machine.cmd_line = Some(cmd_place.ptr);
157 // Store the UTF-16 string. We just allocated so we know the bounds are fine.
158 let char_size = Size::from_bytes(2);
159 for (idx, &c) in cmd_utf16.iter().enumerate() {
160 let place = ecx.mplace_field(cmd_place, idx as u64)?;
161 ecx.write_scalar(Scalar::from_uint(c, char_size), place.into())?;
165 args.next().expect_none("start lang item has more arguments than expected");
167 // Set the last_error to 0
168 let errno_layout = ecx.layout_of(tcx.types.u32)?;
169 let errno_place = ecx.allocate(errno_layout, MiriMemoryKind::Static.into());
170 ecx.write_scalar(Scalar::from_u32(0), errno_place.into())?;
171 ecx.machine.last_error = Some(errno_place);
176 pub fn eval_main<'tcx>(tcx: TyCtxt<'tcx>, main_id: DefId, config: MiriConfig) {
177 let mut ecx = 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<'_> = (|| {
191 // Process the result.
194 let leaks = ecx.memory.leak_report();
195 // Disable the leak test on some platforms where we do not
196 // correctly implement TLS destructors.
197 let target_os = ecx.tcx.tcx.sess.target.target.target_os.to_lowercase();
198 let ignore_leaks = target_os == "windows" || target_os == "macos";
199 if !ignore_leaks && leaks != 0 {
200 tcx.sess.err("the evaluated program leaked memory");
204 // Special treatment for some error kinds
205 let msg = match e.kind {
206 InterpError::Exit(code) => std::process::exit(code),
207 err_unsup!(NoMirFor(..)) =>
208 format!("{}. Did you set `MIRI_SYSROOT` to a Miri-enabled sysroot? You can prepare one with `cargo miri setup`.", e),
212 if let Some(frame) = ecx.stack().last() {
213 let block = &frame.body.basic_blocks()[frame.block.unwrap()];
214 let span = if frame.stmt < block.statements.len() {
215 block.statements[frame.stmt].source_info.span
217 block.terminator().source_info.span
220 let msg = format!("Miri evaluation error: {}", msg);
221 let mut err = ecx.tcx.sess.struct_span_err(span, msg.as_str());
222 let frames = ecx.generate_stacktrace(None);
223 err.span_label(span, msg);
224 // We iterate with indices because we need to look at the next frame (the caller).
225 for idx in 0..frames.len() {
226 let frame_info = &frames[idx];
227 let call_site_is_local = frames.get(idx + 1).map_or(false, |caller_info| {
228 caller_info.instance.def_id().is_local()
230 if call_site_is_local {
231 err.span_note(frame_info.call_site, &frame_info.to_string());
233 err.note(&frame_info.to_string());
238 ecx.tcx.sess.err(&msg);
241 for (i, frame) in ecx.stack().iter().enumerate() {
242 trace!("-------------------");
243 trace!("Frame {}", i);
244 trace!(" return: {:?}", frame.return_place.map(|p| *p));
245 for (i, local) in frame.locals.iter().enumerate() {
246 trace!(" local {}: {:?}", i, local.value);