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,
17 /// Configuration needed to spawn a Miri instance.
19 pub struct MiriConfig {
21 pub args: Vec<String>,
23 // The seed to use when non-determinism is required (e.g. getrandom())
28 pub fn create_ecx<'mir, 'tcx: 'mir>(
32 ) -> InterpResult<'tcx, InterpCx<'mir, 'tcx, Evaluator<'tcx>>> {
33 let mut ecx = InterpCx::new(
34 tcx.at(syntax::source_map::DUMMY_SP),
35 ty::ParamEnv::reveal_all(),
37 MemoryExtra::new(StdRng::seed_from_u64(config.seed.unwrap_or(0)), config.validate),
40 let main_instance = ty::Instance::mono(ecx.tcx.tcx, main_id);
41 let main_mir = ecx.load_mir(main_instance.def)?;
43 if !main_mir.return_ty().is_unit() || main_mir.arg_count != 0 {
45 "miri does not support main functions without `fn()` type signatures"
49 let start_id = tcx.lang_items().start_fn().unwrap();
50 let main_ret_ty = tcx.fn_sig(main_id).output();
51 let main_ret_ty = main_ret_ty.no_bound_vars().unwrap();
52 let start_instance = ty::Instance::resolve(
54 ty::ParamEnv::reveal_all(),
57 ::std::iter::once(ty::subst::Kind::from(main_ret_ty)))
59 let start_mir = ecx.load_mir(start_instance.def)?;
61 if start_mir.arg_count != 3 {
63 "'start' lang item should have three arguments, but has {}",
68 // Return value (in static memory so that it does not count as leak).
69 let ret = ecx.layout_of(start_mir.return_ty())?;
70 let ret_ptr = ecx.allocate(ret, MiriMemoryKind::Static.into());
72 // Push our stack frame.
75 // There is no call site.
79 StackPopCleanup::None { cleanup: true },
82 let mut args = ecx.frame().body.args_iter();
84 // First argument: pointer to `main()`.
85 let main_ptr = ecx.memory_mut().create_fn_alloc(FnVal::Instance(main_instance));
86 let dest = ecx.local_place(args.next().unwrap())?;
87 ecx.write_scalar(Scalar::Ptr(main_ptr), dest)?;
89 // Second argument (argc): `1`.
90 let dest = ecx.local_place(args.next().unwrap())?;
91 let argc = Scalar::from_uint(config.args.len() as u128, dest.layout.size);
92 ecx.write_scalar(argc, dest)?;
93 // Store argc for macOS's `_NSGetArgc`.
95 let argc_place = ecx.allocate(dest.layout, MiriMemoryKind::Env.into());
96 ecx.write_scalar(argc, argc_place.into())?;
97 ecx.machine.argc = Some(argc_place.ptr.to_ptr()?);
100 // Third argument (`argv`): created from `config.args`.
101 let dest = ecx.local_place(args.next().unwrap())?;
102 // For Windows, construct a command string with all the aguments.
103 let mut cmd = String::new();
104 for arg in config.args.iter() {
108 cmd.push_str(&*shell_escape::windows::escape(arg.as_str().into()));
110 // Don't forget `0` terminator.
111 cmd.push(std::char::from_u32(0).unwrap());
112 // Collect the pointers to the individual strings.
113 let mut argvs = Vec::<Pointer<Tag>>::new();
114 for arg in config.args {
115 // Add `0` terminator.
116 let mut arg = arg.into_bytes();
118 argvs.push(ecx.memory_mut().allocate_static_bytes(arg.as_slice(), MiriMemoryKind::Static.into()));
120 // Make an array with all these pointers, in the Miri memory.
121 let argvs_layout = ecx.layout_of(ecx.tcx.mk_array(ecx.tcx.mk_imm_ptr(ecx.tcx.types.u8), argvs.len() as u64))?;
122 let argvs_place = ecx.allocate(argvs_layout, MiriMemoryKind::Env.into());
123 for (idx, arg) in argvs.into_iter().enumerate() {
124 let place = ecx.mplace_field(argvs_place, idx as u64)?;
125 ecx.write_scalar(Scalar::Ptr(arg), place.into())?;
127 ecx.memory_mut().mark_immutable(argvs_place.ptr.assert_ptr().alloc_id)?;
128 // Write a pointer to that place as the argument.
129 let argv = argvs_place.ptr;
130 ecx.write_scalar(argv, dest)?;
131 // Store `argv` for macOS `_NSGetArgv`.
133 let argv_place = ecx.allocate(dest.layout, MiriMemoryKind::Env.into());
134 ecx.write_scalar(argv, argv_place.into())?;
135 ecx.machine.argv = Some(argv_place.ptr.to_ptr()?);
137 // Store command line as UTF-16 for Windows `GetCommandLineW`.
139 let tcx = &{ecx.tcx.tcx};
140 let cmd_utf16: Vec<u16> = cmd.encode_utf16().collect();
141 let cmd_ptr = ecx.memory_mut().allocate(
142 Size::from_bytes(cmd_utf16.len() as u64 * 2),
143 Align::from_bytes(2).unwrap(),
144 MiriMemoryKind::Env.into(),
146 ecx.machine.cmd_line = Some(cmd_ptr);
147 // Store the UTF-16 string.
148 let char_size = Size::from_bytes(2);
149 let cmd_alloc = ecx.memory_mut().get_mut(cmd_ptr.alloc_id)?;
150 let mut cur_ptr = cmd_ptr;
151 for &c in cmd_utf16.iter() {
152 cmd_alloc.write_scalar(
155 Scalar::from_uint(c, char_size).into(),
158 cur_ptr = cur_ptr.offset(char_size, tcx)?;
162 assert!(args.next().is_none(), "start lang item has more arguments than expected");
167 pub fn eval_main<'tcx>(
172 let mut ecx = match create_ecx(tcx, main_id, config) {
175 err.print_backtrace();
176 panic!("Miri initialziation error: {}", err.kind)
180 // Perform the main execution.
181 let res: InterpResult<'_> = (|| {
186 // Process the result.
189 let leaks = ecx.memory().leak_report();
190 // Disable the leak test on some platforms where we do not
191 // correctly implement TLS destructors.
192 let target_os = ecx.tcx.tcx.sess.target.target.target_os.to_lowercase();
193 let ignore_leaks = target_os == "windows" || target_os == "macos";
194 if !ignore_leaks && leaks != 0 {
195 tcx.sess.err("the evaluated program leaked memory");
199 // Special treatment for some error kinds
200 let msg = match e.kind {
201 InterpError::Exit(code) => std::process::exit(code),
202 err_unsup!(NoMirFor(..)) =>
203 format!("{}. Did you set `MIRI_SYSROOT` to a Miri-enabled sysroot? You can prepare one with `cargo miri setup`.", e),
207 if let Some(frame) = ecx.stack().last() {
208 let block = &frame.body.basic_blocks()[frame.block];
209 let span = if frame.stmt < block.statements.len() {
210 block.statements[frame.stmt].source_info.span
212 block.terminator().source_info.span
215 let msg = format!("Miri evaluation error: {}", msg);
216 let mut err = struct_error(ecx.tcx.tcx.at(span), msg.as_str());
217 let frames = ecx.generate_stacktrace(None);
218 err.span_label(span, msg);
219 // We iterate with indices because we need to look at the next frame (the caller).
220 for idx in 0..frames.len() {
221 let frame_info = &frames[idx];
222 let call_site_is_local = frames.get(idx+1).map_or(false,
223 |caller_info| caller_info.instance.def_id().is_local());
224 if call_site_is_local {
225 err.span_note(frame_info.call_site, &frame_info.to_string());
227 err.note(&frame_info.to_string());
232 ecx.tcx.sess.err(&msg);
235 for (i, frame) in ecx.stack().iter().enumerate() {
236 trace!("-------------------");
237 trace!("Frame {}", i);
238 trace!(" return: {:?}", frame.return_place.map(|p| *p));
239 for (i, local) in frame.locals.iter().enumerate() {
240 trace!(" local {}: {:?}", i, local.value);