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 /// Command-line arguments passed to the interpreted program.
28 pub args: Vec<String>,
29 /// The seed to use when non-determinism or randomness are required (e.g. ptr-to-int cast, `getrandom()`).
30 pub seed: Option<u64>,
34 pub fn create_ecx<'mir, 'tcx: 'mir>(
38 ) -> InterpResult<'tcx, InterpCx<'mir, 'tcx, Evaluator<'tcx>>> {
39 let mut ecx = InterpCx::new(
40 tcx.at(syntax::source_map::DUMMY_SP),
41 ty::ParamEnv::reveal_all(),
42 Evaluator::new(config.communicate),
43 MemoryExtra::new(StdRng::seed_from_u64(config.seed.unwrap_or(0)), config.validate),
45 // Complete initialization.
46 EnvVars::init(&mut ecx, config.excluded_env_vars);
48 // Setup first stack-frame
49 let main_instance = ty::Instance::mono(ecx.tcx.tcx, main_id);
50 let main_mir = ecx.load_mir(main_instance.def, None)?;
52 if !main_mir.return_ty().is_unit() || main_mir.arg_count != 0 {
54 "miri does not support main functions without `fn()` type signatures"
58 let start_id = tcx.lang_items().start_fn().unwrap();
59 let main_ret_ty = tcx.fn_sig(main_id).output();
60 let main_ret_ty = main_ret_ty.no_bound_vars().unwrap();
61 let start_instance = ty::Instance::resolve(
63 ty::ParamEnv::reveal_all(),
66 ::std::iter::once(ty::subst::Kind::from(main_ret_ty)))
68 let start_mir = ecx.load_mir(start_instance.def, None)?;
70 if start_mir.arg_count != 3 {
72 "'start' lang item should have three arguments, but has {}",
77 // Return value (in static memory so that it does not count as leak).
78 let ret = ecx.layout_of(start_mir.return_ty())?;
79 let ret_ptr = ecx.allocate(ret, MiriMemoryKind::Static.into());
81 // Push our stack frame.
84 // There is no call site.
88 StackPopCleanup::None { cleanup: true },
91 let mut args = ecx.frame().body.args_iter();
93 // First argument: pointer to `main()`.
94 let main_ptr = ecx.memory_mut().create_fn_alloc(FnVal::Instance(main_instance));
95 let dest = ecx.local_place(args.next().unwrap())?;
96 ecx.write_scalar(Scalar::Ptr(main_ptr), dest)?;
98 // Second argument (argc): `1`.
99 let dest = ecx.local_place(args.next().unwrap())?;
100 let argc = Scalar::from_uint(config.args.len() as u128, dest.layout.size);
101 ecx.write_scalar(argc, dest)?;
102 // Store argc for macOS's `_NSGetArgc`.
104 let argc_place = ecx.allocate(dest.layout, MiriMemoryKind::Env.into());
105 ecx.write_scalar(argc, argc_place.into())?;
106 ecx.machine.argc = Some(argc_place.ptr.to_ptr()?);
109 // Third argument (`argv`): created from `config.args`.
110 let dest = ecx.local_place(args.next().unwrap())?;
111 // For Windows, construct a command string with all the aguments.
112 let mut cmd = String::new();
113 for arg in config.args.iter() {
117 cmd.push_str(&*shell_escape::windows::escape(arg.as_str().into()));
119 // Don't forget `0` terminator.
120 cmd.push(std::char::from_u32(0).unwrap());
121 // Collect the pointers to the individual strings.
122 let mut argvs = Vec::<Pointer<Tag>>::new();
123 for arg in config.args {
124 // Add `0` terminator.
125 let mut arg = arg.into_bytes();
127 argvs.push(ecx.memory_mut().allocate_static_bytes(arg.as_slice(), MiriMemoryKind::Static.into()));
129 // Make an array with all these pointers, in the Miri memory.
130 let argvs_layout = ecx.layout_of(ecx.tcx.mk_array(ecx.tcx.mk_imm_ptr(ecx.tcx.types.u8), argvs.len() as u64))?;
131 let argvs_place = ecx.allocate(argvs_layout, MiriMemoryKind::Env.into());
132 for (idx, arg) in argvs.into_iter().enumerate() {
133 let place = ecx.mplace_field(argvs_place, idx as u64)?;
134 ecx.write_scalar(Scalar::Ptr(arg), place.into())?;
136 ecx.memory_mut().mark_immutable(argvs_place.ptr.assert_ptr().alloc_id)?;
137 // Write a pointer to that place as the argument.
138 let argv = argvs_place.ptr;
139 ecx.write_scalar(argv, dest)?;
140 // Store `argv` for macOS `_NSGetArgv`.
142 let argv_place = ecx.allocate(dest.layout, MiriMemoryKind::Env.into());
143 ecx.write_scalar(argv, argv_place.into())?;
144 ecx.machine.argv = Some(argv_place.ptr.to_ptr()?);
146 // Store command line as UTF-16 for Windows `GetCommandLineW`.
148 let tcx = &{ecx.tcx.tcx};
149 let cmd_utf16: Vec<u16> = cmd.encode_utf16().collect();
150 let cmd_ptr = ecx.memory_mut().allocate(
151 Size::from_bytes(cmd_utf16.len() as u64 * 2),
152 Align::from_bytes(2).unwrap(),
153 MiriMemoryKind::Env.into(),
155 ecx.machine.cmd_line = Some(cmd_ptr);
156 // Store the UTF-16 string.
157 let char_size = Size::from_bytes(2);
158 let cmd_alloc = ecx.memory_mut().get_mut(cmd_ptr.alloc_id)?;
159 let mut cur_ptr = cmd_ptr;
160 for &c in cmd_utf16.iter() {
161 cmd_alloc.write_scalar(
164 Scalar::from_uint(c, char_size).into(),
167 cur_ptr = cur_ptr.offset(char_size, tcx)?;
171 assert!(args.next().is_none(), "start lang item has more arguments than expected");
176 pub fn eval_main<'tcx>(
181 let mut ecx = match create_ecx(tcx, main_id, config) {
184 err.print_backtrace();
185 panic!("Miri initialziation error: {}", err.kind)
189 // Perform the main execution.
190 let res: InterpResult<'_> = (|| {
195 // Process the result.
198 let leaks = ecx.memory().leak_report();
199 // Disable the leak test on some platforms where we do not
200 // correctly implement TLS destructors.
201 let target_os = ecx.tcx.tcx.sess.target.target.target_os.to_lowercase();
202 let ignore_leaks = target_os == "windows" || target_os == "macos";
203 if !ignore_leaks && leaks != 0 {
204 tcx.sess.err("the evaluated program leaked memory");
208 // Special treatment for some error kinds
209 let msg = match e.kind {
210 InterpError::Exit(code) => std::process::exit(code),
211 err_unsup!(NoMirFor(..)) =>
212 format!("{}. Did you set `MIRI_SYSROOT` to a Miri-enabled sysroot? You can prepare one with `cargo miri setup`.", e),
216 if let Some(frame) = ecx.stack().last() {
217 let block = &frame.body.basic_blocks()[frame.block];
218 let span = if frame.stmt < block.statements.len() {
219 block.statements[frame.stmt].source_info.span
221 block.terminator().source_info.span
224 let msg = format!("Miri evaluation error: {}", msg);
225 let mut err = struct_error(ecx.tcx.tcx.at(span), msg.as_str());
226 let frames = ecx.generate_stacktrace(None);
227 err.span_label(span, msg);
228 // We iterate with indices because we need to look at the next frame (the caller).
229 for idx in 0..frames.len() {
230 let frame_info = &frames[idx];
231 let call_site_is_local = frames.get(idx+1).map_or(false,
232 |caller_info| caller_info.instance.def_id().is_local());
233 if call_site_is_local {
234 err.span_note(frame_info.call_site, &frame_info.to_string());
236 err.note(&frame_info.to_string());
241 ecx.tcx.sess.err(&msg);
244 for (i, frame) in ecx.stack().iter().enumerate() {
245 trace!("-------------------");
246 trace!("Frame {}", i);
247 trace!(" return: {:?}", frame.return_place.map(|p| *p));
248 for (i, local) in frame.locals.iter().enumerate() {
249 trace!(" local {}: {:?}", i, local.value);