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,
14 TlsEvalContextExt, MPlaceTy
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>,
32 /// Returns a freshly created `InterpCx`, along with an `MPlaceTy` representing
33 /// the location where the return value of the `start` lang item will be
35 /// Public because this is also used by `priroda`.
36 pub fn create_ecx<'mir, 'tcx: 'mir>(
40 ) -> InterpResult<'tcx, (InterpCx<'mir, 'tcx, Evaluator<'tcx>>, MPlaceTy<'tcx, Tag>)> {
41 let mut ecx = InterpCx::new(
42 tcx.at(syntax::source_map::DUMMY_SP),
43 ty::ParamEnv::reveal_all(),
44 Evaluator::new(config.communicate),
45 MemoryExtra::new(StdRng::seed_from_u64(config.seed.unwrap_or(0)), config.validate),
47 // Complete initialization.
48 EnvVars::init(&mut ecx, config.excluded_env_vars);
50 // Setup first stack-frame
51 let main_instance = ty::Instance::mono(tcx, main_id);
52 let main_mir = ecx.load_mir(main_instance.def, None)?;
54 if !main_mir.return_ty().is_unit() || main_mir.arg_count != 0 {
55 throw_unsup_format!("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(),
65 tcx.mk_substs(::std::iter::once(ty::subst::GenericArg::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()`.
96 .create_fn_alloc(FnVal::Instance(main_instance));
97 let dest = ecx.local_place(args.next().unwrap())?;
98 ecx.write_scalar(Scalar::Ptr(main_ptr), dest)?;
100 // Second argument (argc): `1`.
101 let dest = ecx.local_place(args.next().unwrap())?;
102 let argc = Scalar::from_uint(config.args.len() as u128, dest.layout.size);
103 ecx.write_scalar(argc, dest)?;
104 // Store argc for macOS's `_NSGetArgc`.
106 let argc_place = ecx.allocate(dest.layout, MiriMemoryKind::Env.into());
107 ecx.write_scalar(argc, argc_place.into())?;
108 ecx.machine.argc = Some(argc_place.ptr);
111 // Third argument (`argv`): created from `config.args`.
112 let dest = ecx.local_place(args.next().unwrap())?;
113 // For Windows, construct a command string with all the aguments.
114 let mut cmd = String::new();
115 for arg in config.args.iter() {
119 cmd.push_str(&*shell_escape::windows::escape(arg.as_str().into()));
121 // Don't forget `0` terminator.
122 cmd.push(std::char::from_u32(0).unwrap());
123 // Collect the pointers to the individual strings.
124 let mut argvs = Vec::<Pointer<Tag>>::new();
125 for arg in config.args {
126 // Add `0` terminator.
127 let mut arg = arg.into_bytes();
131 .allocate_static_bytes(arg.as_slice(), MiriMemoryKind::Static.into()),
134 // Make an array with all these pointers, in the Miri memory.
135 let argvs_layout = ecx.layout_of(
136 tcx.mk_array(tcx.mk_imm_ptr(tcx.types.u8), argvs.len() as u64),
138 let argvs_place = ecx.allocate(argvs_layout, MiriMemoryKind::Env.into());
139 for (idx, arg) in argvs.into_iter().enumerate() {
140 let place = ecx.mplace_field(argvs_place, idx as u64)?;
141 ecx.write_scalar(Scalar::Ptr(arg), place.into())?;
144 .mark_immutable(argvs_place.ptr.assert_ptr().alloc_id)?;
145 // Write a pointer to that place as the argument.
146 let argv = argvs_place.ptr;
147 ecx.write_scalar(argv, dest)?;
148 // Store `argv` for macOS `_NSGetArgv`.
150 let argv_place = ecx.allocate(dest.layout, MiriMemoryKind::Env.into());
151 ecx.write_scalar(argv, argv_place.into())?;
152 ecx.machine.argv = Some(argv_place.ptr);
154 // Store command line as UTF-16 for Windows `GetCommandLineW`.
156 let cmd_utf16: Vec<u16> = cmd.encode_utf16().collect();
157 let cmd_type = tcx.mk_array(tcx.types.u16, cmd_utf16.len() as u64);
158 let cmd_place = ecx.allocate(ecx.layout_of(cmd_type)?, MiriMemoryKind::Env.into());
159 ecx.machine.cmd_line = Some(cmd_place.ptr);
160 // Store the UTF-16 string. We just allocated so we know the bounds are fine.
161 let char_size = Size::from_bytes(2);
162 for (idx, &c) in cmd_utf16.iter().enumerate() {
163 let place = ecx.mplace_field(cmd_place, idx as u64)?;
164 ecx.write_scalar(Scalar::from_uint(c, char_size), place.into())?;
168 args.next().expect_none("start lang item has more arguments than expected");
170 // Set the last_error to 0
171 let errno_layout = ecx.layout_of(tcx.types.u32)?;
172 let errno_place = ecx.allocate(errno_layout, MiriMemoryKind::Static.into());
173 ecx.write_scalar(Scalar::from_u32(0), errno_place.into())?;
174 ecx.machine.last_error = Some(errno_place);
179 /// Evaluates the main function specified by `main_id`.
180 /// Returns `Some(return_code)` if program executed completed.
181 /// Returns `None` if an evaluation error occured.
182 pub fn eval_main<'tcx>(tcx: TyCtxt<'tcx>, main_id: DefId, config: MiriConfig) -> Option<i64> {
183 let (mut ecx, ret_ptr) = match create_ecx(tcx, main_id, config) {
186 err.print_backtrace();
187 panic!("Miri initialziation error: {}", err.kind)
191 // Perform the main execution.
192 let res: InterpResult<'_, i64> = (|| {
194 // Read the return code pointer *before* we run TLS destructors, to assert
195 // that it was written to by the time that `start` lang item returned.
196 let return_code = ecx.read_scalar(ret_ptr.into())?.not_undef()?.to_machine_isize(&ecx)?;
197 ecx.run_tls_dtors()?;
201 // Process the result.
204 // Disable the leak test on some platforms where we do not
205 // correctly implement TLS destructors.
206 let target_os = ecx.tcx.tcx.sess.target.target.target_os.to_lowercase();
207 let ignore_leaks = target_os == "windows" || target_os == "macos";
209 let leaks = ecx.memory.leak_report();
211 tcx.sess.err("the evaluated program leaked memory");
212 // Ignore the provided return code - let the reported error
213 // determine the return code.
217 return Some(return_code)
220 // Special treatment for some error kinds
221 let msg = match e.kind {
222 InterpError::Exit(code) => return Some(code.into()),
223 err_unsup!(NoMirFor(..)) =>
224 format!("{}. Did you set `MIRI_SYSROOT` to a Miri-enabled sysroot? You can prepare one with `cargo miri setup`.", e),
228 if let Some(frame) = ecx.stack().last() {
229 let block = &frame.body.basic_blocks()[frame.block.unwrap()];
230 let span = if frame.stmt < block.statements.len() {
231 block.statements[frame.stmt].source_info.span
233 block.terminator().source_info.span
236 let msg = format!("Miri evaluation error: {}", msg);
237 let mut err = ecx.tcx.sess.struct_span_err(span, msg.as_str());
238 let frames = ecx.generate_stacktrace(None);
239 err.span_label(span, msg);
240 // We iterate with indices because we need to look at the next frame (the caller).
241 for idx in 0..frames.len() {
242 let frame_info = &frames[idx];
243 let call_site_is_local = frames.get(idx + 1).map_or(false, |caller_info| {
244 caller_info.instance.def_id().is_local()
246 if call_site_is_local {
247 err.span_note(frame_info.call_site, &frame_info.to_string());
249 err.note(&frame_info.to_string());
254 ecx.tcx.sess.err(&msg);
257 for (i, frame) in ecx.stack().iter().enumerate() {
258 trace!("-------------------");
259 trace!("Frame {}", i);
260 trace!(" return: {:?}", frame.return_place.map(|p| *p));
261 for (i, local) in frame.locals.iter().enumerate() {
262 trace!(" local {}: {:?}", i, local.value);
265 // Let the reported error determine the return code.