1 //! Main evaluator loop and setting up the initial stack frame.
3 use rand::rngs::StdRng;
6 use syntax::source_map::DUMMY_SP;
7 use rustc::ty::{self, TyCtxt};
8 use rustc::ty::layout::{LayoutOf, Size, Align};
9 use rustc::hir::def_id::DefId;
12 InterpResult, InterpError, InterpCx, StackPopCleanup, struct_error,
13 Scalar, Tag, Pointer, FnVal,
14 MemoryExtra, MiriMemoryKind, Evaluator, TlsEvalContextExt, HelpersEvalContextExt,
18 /// Configuration needed to spawn a Miri instance.
20 pub struct MiriConfig {
21 /// Determine if validity checking and Stacked Borrows are enabled.
23 /// Determines if communication with the host environment is enabled.
24 pub communicate: bool,
25 /// Environment variables that should always be isolated from the host.
26 pub excluded_env_vars: Vec<String>,
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);
47 // Setup first stack-frame
48 let main_instance = ty::Instance::mono(ecx.tcx.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 {
53 "miri does not support main functions without `fn()` type signatures"
57 let start_id = tcx.lang_items().start_fn().unwrap();
58 let main_ret_ty = tcx.fn_sig(main_id).output();
59 let main_ret_ty = main_ret_ty.no_bound_vars().unwrap();
60 let start_instance = ty::Instance::resolve(
62 ty::ParamEnv::reveal_all(),
65 ::std::iter::once(ty::subst::Kind::from(main_ret_ty)))
67 let start_mir = ecx.load_mir(start_instance.def, None)?;
69 if start_mir.arg_count != 3 {
71 "'start' lang item should have three arguments, but has {}",
76 // Return value (in static memory so that it does not count as leak).
77 let ret = ecx.layout_of(start_mir.return_ty())?;
78 let ret_ptr = ecx.allocate(ret, MiriMemoryKind::Static.into());
80 // Push our stack frame.
83 // There is no call site.
87 StackPopCleanup::None { cleanup: true },
90 let mut args = ecx.frame().body.args_iter();
92 // First argument: pointer to `main()`.
93 let main_ptr = ecx.memory_mut().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.to_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();
126 argvs.push(ecx.memory_mut().allocate_static_bytes(arg.as_slice(), MiriMemoryKind::Static.into()));
128 // Make an array with all these pointers, in the Miri memory.
129 let argvs_layout = ecx.layout_of(ecx.tcx.mk_array(ecx.tcx.mk_imm_ptr(ecx.tcx.types.u8), argvs.len() as u64))?;
130 let argvs_place = ecx.allocate(argvs_layout, MiriMemoryKind::Env.into());
131 for (idx, arg) in argvs.into_iter().enumerate() {
132 let place = ecx.mplace_field(argvs_place, idx as u64)?;
133 ecx.write_scalar(Scalar::Ptr(arg), place.into())?;
135 ecx.memory_mut().mark_immutable(argvs_place.ptr.assert_ptr().alloc_id)?;
136 // Write a pointer to that place as the argument.
137 let argv = argvs_place.ptr;
138 ecx.write_scalar(argv, dest)?;
139 // Store `argv` for macOS `_NSGetArgv`.
141 let argv_place = ecx.allocate(dest.layout, MiriMemoryKind::Env.into());
142 ecx.write_scalar(argv, argv_place.into())?;
143 ecx.machine.argv = Some(argv_place.ptr.to_ptr()?);
145 // Store command line as UTF-16 for Windows `GetCommandLineW`.
147 let tcx = &{ecx.tcx.tcx};
148 let cmd_utf16: Vec<u16> = cmd.encode_utf16().collect();
149 let cmd_ptr = ecx.memory_mut().allocate(
150 Size::from_bytes(cmd_utf16.len() as u64 * 2),
151 Align::from_bytes(2).unwrap(),
152 MiriMemoryKind::Env.into(),
154 ecx.machine.cmd_line = Some(cmd_ptr);
155 // Store the UTF-16 string.
156 let char_size = Size::from_bytes(2);
157 let cmd_alloc = ecx.memory_mut().get_mut(cmd_ptr.alloc_id)?;
158 let mut cur_ptr = cmd_ptr;
159 for &c in cmd_utf16.iter() {
160 cmd_alloc.write_scalar(
163 Scalar::from_uint(c, char_size).into(),
166 cur_ptr = cur_ptr.offset(char_size, tcx)?;
170 assert!(args.next().is_none(), "start lang item has more arguments than expected");
175 pub fn eval_main<'tcx>(
180 let mut ecx = match create_ecx(tcx, main_id, config) {
183 err.print_backtrace();
184 panic!("Miri initialziation error: {}", err.kind)
188 // Perform the main execution.
189 let res: InterpResult<'_> = (|| {
194 // Process the result.
197 let leaks = ecx.memory().leak_report();
198 // Disable the leak test on some platforms where we do not
199 // correctly implement TLS destructors.
200 let target_os = ecx.tcx.tcx.sess.target.target.target_os.to_lowercase();
201 let ignore_leaks = target_os == "windows" || target_os == "macos";
202 if !ignore_leaks && leaks != 0 {
203 tcx.sess.err("the evaluated program leaked memory");
207 // Special treatment for some error kinds
208 let msg = match e.kind {
209 InterpError::Exit(code) => std::process::exit(code),
210 err_unsup!(NoMirFor(..)) =>
211 format!("{}. Did you set `MIRI_SYSROOT` to a Miri-enabled sysroot? You can prepare one with `cargo miri setup`.", e),
215 if let Some(frame) = ecx.stack().last() {
216 let block = &frame.body.basic_blocks()[frame.block];
217 let span = if frame.stmt < block.statements.len() {
218 block.statements[frame.stmt].source_info.span
220 block.terminator().source_info.span
223 let msg = format!("Miri evaluation error: {}", msg);
224 let mut err = struct_error(ecx.tcx.tcx.at(span), msg.as_str());
225 let frames = ecx.generate_stacktrace(None);
226 err.span_label(span, msg);
227 // We iterate with indices because we need to look at the next frame (the caller).
228 for idx in 0..frames.len() {
229 let frame_info = &frames[idx];
230 let call_site_is_local = frames.get(idx+1).map_or(false,
231 |caller_info| caller_info.instance.def_id().is_local());
232 if call_site_is_local {
233 err.span_note(frame_info.call_site, &frame_info.to_string());
235 err.note(&frame_info.to_string());
240 ecx.tcx.sess.err(&msg);
243 for (i, frame) in ecx.stack().iter().enumerate() {
244 trace!("-------------------");
245 trace!("Frame {}", i);
246 trace!(" return: {:?}", frame.return_place.map(|p| *p));
247 for (i, local) in frame.locals.iter().enumerate() {
248 trace!(" local {}: {:?}", i, local.value);