miri/
eval.rs

1//! Main evaluator loop and setting up the initial stack frame.
2
3use std::ffi::{OsStr, OsString};
4use std::panic::{self, AssertUnwindSafe};
5use std::path::PathBuf;
6use std::rc::Rc;
7use std::task::Poll;
8use std::{iter, thread};
9
10use rustc_abi::ExternAbi;
11use rustc_data_structures::fx::{FxHashMap, FxHashSet};
12use rustc_hir::def::Namespace;
13use rustc_hir::def_id::DefId;
14use rustc_middle::ty::layout::{LayoutCx, LayoutOf};
15use rustc_middle::ty::{self, Ty, TyCtxt};
16use rustc_session::config::EntryFnType;
17
18use crate::concurrency::GenmcCtx;
19use crate::concurrency::thread::TlsAllocAction;
20use crate::diagnostics::report_leaks;
21use crate::shims::tls;
22use crate::*;
23
24#[derive(Copy, Clone, Debug)]
25pub enum MiriEntryFnType {
26    MiriStart,
27    Rustc(EntryFnType),
28}
29
30/// When the main thread would exit, we will yield to any other thread that is ready to execute.
31/// But we must only do that a finite number of times, or a background thread running `loop {}`
32/// will hang the program.
33const MAIN_THREAD_YIELDS_AT_SHUTDOWN: u32 = 256;
34
35#[derive(Copy, Clone, Debug, PartialEq)]
36pub enum AlignmentCheck {
37    /// Do not check alignment.
38    None,
39    /// Check alignment "symbolically", i.e., using only the requested alignment for an allocation and not its real base address.
40    Symbolic,
41    /// Check alignment on the actual physical integer address.
42    Int,
43}
44
45#[derive(Copy, Clone, Debug, PartialEq)]
46pub enum RejectOpWith {
47    /// Isolated op is rejected with an abort of the machine.
48    Abort,
49
50    /// If not Abort, miri returns an error for an isolated op.
51    /// Following options determine if user should be warned about such error.
52    /// Do not print warning about rejected isolated op.
53    NoWarning,
54
55    /// Print a warning about rejected isolated op, with backtrace.
56    Warning,
57
58    /// Print a warning about rejected isolated op, without backtrace.
59    WarningWithoutBacktrace,
60}
61
62#[derive(Copy, Clone, Debug, PartialEq)]
63pub enum IsolatedOp {
64    /// Reject an op requiring communication with the host. By
65    /// default, miri rejects the op with an abort. If not, it returns
66    /// an error code, and prints a warning about it. Warning levels
67    /// are controlled by `RejectOpWith` enum.
68    Reject(RejectOpWith),
69
70    /// Execute op requiring communication with the host, i.e. disable isolation.
71    Allow,
72}
73
74#[derive(Debug, Copy, Clone, PartialEq, Eq)]
75pub enum BacktraceStyle {
76    /// Prints a terser backtrace which ideally only contains relevant information.
77    Short,
78    /// Prints a backtrace with all possible information.
79    Full,
80    /// Prints only the frame that the error occurs in.
81    Off,
82}
83
84#[derive(Debug, Copy, Clone, PartialEq, Eq)]
85pub enum ValidationMode {
86    /// Do not perform any kind of validation.
87    No,
88    /// Validate the interior of the value, but not things behind references.
89    Shallow,
90    /// Fully recursively validate references.
91    Deep,
92}
93
94/// Configuration needed to spawn a Miri instance.
95#[derive(Clone)]
96pub struct MiriConfig {
97    /// The host environment snapshot to use as basis for what is provided to the interpreted program.
98    /// (This is still subject to isolation as well as `forwarded_env_vars`.)
99    pub env: Vec<(OsString, OsString)>,
100    /// Determine if validity checking is enabled.
101    pub validation: ValidationMode,
102    /// Determines if Stacked Borrows or Tree Borrows is enabled.
103    pub borrow_tracker: Option<BorrowTrackerMethod>,
104    /// Controls alignment checking.
105    pub check_alignment: AlignmentCheck,
106    /// Action for an op requiring communication with the host.
107    pub isolated_op: IsolatedOp,
108    /// Determines if memory leaks should be ignored.
109    pub ignore_leaks: bool,
110    /// Environment variables that should always be forwarded from the host.
111    pub forwarded_env_vars: Vec<String>,
112    /// Additional environment variables that should be set in the interpreted program.
113    pub set_env_vars: FxHashMap<String, String>,
114    /// Command-line arguments passed to the interpreted program.
115    pub args: Vec<String>,
116    /// The seed to use when non-determinism or randomness are required (e.g. ptr-to-int cast, `getrandom()`).
117    pub seed: Option<u64>,
118    /// The stacked borrows pointer ids to report about.
119    pub tracked_pointer_tags: FxHashSet<BorTag>,
120    /// The allocation ids to report about.
121    pub tracked_alloc_ids: FxHashSet<AllocId>,
122    /// For the tracked alloc ids, also report read/write accesses.
123    pub track_alloc_accesses: bool,
124    /// Determine if data race detection should be enabled.
125    pub data_race_detector: bool,
126    /// Determine if weak memory emulation should be enabled. Requires data race detection to be enabled.
127    pub weak_memory_emulation: bool,
128    /// Determine if we are running in GenMC mode. In this mode, Miri will explore multiple concurrent executions of the given program.
129    pub genmc_mode: bool,
130    /// Track when an outdated (weak memory) load happens.
131    pub track_outdated_loads: bool,
132    /// Rate of spurious failures for compare_exchange_weak atomic operations,
133    /// between 0.0 and 1.0, defaulting to 0.8 (80% chance of failure).
134    pub cmpxchg_weak_failure_rate: f64,
135    /// If `Some`, enable the `measureme` profiler, writing results to a file
136    /// with the specified prefix.
137    pub measureme_out: Option<String>,
138    /// Which style to use for printing backtraces.
139    pub backtrace_style: BacktraceStyle,
140    /// Which provenance to use for int2ptr casts.
141    pub provenance_mode: ProvenanceMode,
142    /// Whether to ignore any output by the program. This is helpful when debugging miri
143    /// as its messages don't get intermingled with the program messages.
144    pub mute_stdout_stderr: bool,
145    /// The probability of the active thread being preempted at the end of each basic block.
146    pub preemption_rate: f64,
147    /// Report the current instruction being executed every N basic blocks.
148    pub report_progress: Option<u32>,
149    /// Whether Stacked Borrows and Tree Borrows retagging should recurse into fields of datatypes.
150    pub retag_fields: RetagFields,
151    /// The location of a shared object file to load when calling external functions
152    /// FIXME! consider allowing users to specify paths to multiple files, or to a directory
153    pub native_lib: Option<PathBuf>,
154    /// Run a garbage collector for BorTags every N basic blocks.
155    pub gc_interval: u32,
156    /// The number of CPUs to be reported by miri.
157    pub num_cpus: u32,
158    /// Requires Miri to emulate pages of a certain size.
159    pub page_size: Option<u64>,
160    /// Whether to collect a backtrace when each allocation is created, just in case it leaks.
161    pub collect_leak_backtraces: bool,
162    /// Probability for address reuse.
163    pub address_reuse_rate: f64,
164    /// Probability for address reuse across threads.
165    pub address_reuse_cross_thread_rate: f64,
166    /// Round Robin scheduling with no preemption.
167    pub fixed_scheduling: bool,
168}
169
170impl Default for MiriConfig {
171    fn default() -> MiriConfig {
172        MiriConfig {
173            env: vec![],
174            validation: ValidationMode::Shallow,
175            borrow_tracker: Some(BorrowTrackerMethod::StackedBorrows),
176            check_alignment: AlignmentCheck::Int,
177            isolated_op: IsolatedOp::Reject(RejectOpWith::Abort),
178            ignore_leaks: false,
179            forwarded_env_vars: vec![],
180            set_env_vars: FxHashMap::default(),
181            args: vec![],
182            seed: None,
183            tracked_pointer_tags: FxHashSet::default(),
184            tracked_alloc_ids: FxHashSet::default(),
185            track_alloc_accesses: false,
186            data_race_detector: true,
187            weak_memory_emulation: true,
188            genmc_mode: false,
189            track_outdated_loads: false,
190            cmpxchg_weak_failure_rate: 0.8, // 80%
191            measureme_out: None,
192            backtrace_style: BacktraceStyle::Short,
193            provenance_mode: ProvenanceMode::Default,
194            mute_stdout_stderr: false,
195            preemption_rate: 0.01, // 1%
196            report_progress: None,
197            retag_fields: RetagFields::Yes,
198            native_lib: None,
199            gc_interval: 10_000,
200            num_cpus: 1,
201            page_size: None,
202            collect_leak_backtraces: true,
203            address_reuse_rate: 0.5,
204            address_reuse_cross_thread_rate: 0.1,
205            fixed_scheduling: false,
206        }
207    }
208}
209
210/// The state of the main thread. Implementation detail of `on_main_stack_empty`.
211#[derive(Default, Debug)]
212enum MainThreadState<'tcx> {
213    #[default]
214    Running,
215    TlsDtors(tls::TlsDtorsState<'tcx>),
216    Yield {
217        remaining: u32,
218    },
219    Done,
220}
221
222impl<'tcx> MainThreadState<'tcx> {
223    fn on_main_stack_empty(
224        &mut self,
225        this: &mut MiriInterpCx<'tcx>,
226    ) -> InterpResult<'tcx, Poll<()>> {
227        use MainThreadState::*;
228        match self {
229            Running => {
230                *self = TlsDtors(Default::default());
231            }
232            TlsDtors(state) =>
233                match state.on_stack_empty(this)? {
234                    Poll::Pending => {} // just keep going
235                    Poll::Ready(()) => {
236                        if this.machine.data_race.as_genmc_ref().is_some() {
237                            // In GenMC mode, we don't yield at the end of the main thread.
238                            // Instead, the `GenmcCtx` will ensure that unfinished threads get a chance to run at this point.
239                            *self = Done;
240                        } else {
241                            // Give background threads a chance to finish by yielding the main thread a
242                            // couple of times -- but only if we would also preempt threads randomly.
243                            if this.machine.preemption_rate > 0.0 {
244                                // There is a non-zero chance they will yield back to us often enough to
245                                // make Miri terminate eventually.
246                                *self = Yield { remaining: MAIN_THREAD_YIELDS_AT_SHUTDOWN };
247                            } else {
248                                // The other threads did not get preempted, so no need to yield back to
249                                // them.
250                                *self = Done;
251                            }
252                        }
253                    }
254                },
255            Yield { remaining } =>
256                match remaining.checked_sub(1) {
257                    None => *self = Done,
258                    Some(new_remaining) => {
259                        *remaining = new_remaining;
260                        this.yield_active_thread();
261                    }
262                },
263            Done => {
264                // Figure out exit code.
265                let ret_place = this.machine.main_fn_ret_place.clone().unwrap();
266                let exit_code = this.read_target_isize(&ret_place)?;
267                // Rust uses `isize` but the underlying type of an exit code is `i32`.
268                // Do a saturating cast.
269                let exit_code = i32::try_from(exit_code).unwrap_or(if exit_code >= 0 {
270                    i32::MAX
271                } else {
272                    i32::MIN
273                });
274                // Deal with our thread-local memory. We do *not* want to actually free it, instead we consider TLS
275                // to be like a global `static`, so that all memory reached by it is considered to "not leak".
276                this.terminate_active_thread(TlsAllocAction::Leak)?;
277
278                // Machine cleanup. Only do this if all threads have terminated; threads that are still running
279                // might cause Stacked Borrows errors (https://github.com/rust-lang/miri/issues/2396).
280                if this.have_all_terminated() {
281                    // Even if all threads have terminated, we have to beware of data races since some threads
282                    // might not have joined the main thread (https://github.com/rust-lang/miri/issues/2020,
283                    // https://github.com/rust-lang/miri/issues/2508).
284                    this.allow_data_races_all_threads_done();
285                    EnvVars::cleanup(this).expect("error during env var cleanup");
286                }
287
288                // Stop interpreter loop.
289                throw_machine_stop!(TerminationInfo::Exit { code: exit_code, leak_check: true });
290            }
291        }
292        interp_ok(Poll::Pending)
293    }
294}
295
296/// Returns a freshly created `InterpCx`.
297/// Public because this is also used by `priroda`.
298pub fn create_ecx<'tcx>(
299    tcx: TyCtxt<'tcx>,
300    entry_id: DefId,
301    entry_type: MiriEntryFnType,
302    config: &MiriConfig,
303    genmc_ctx: Option<Rc<GenmcCtx>>,
304) -> InterpResult<'tcx, InterpCx<'tcx, MiriMachine<'tcx>>> {
305    let typing_env = ty::TypingEnv::fully_monomorphized();
306    let layout_cx = LayoutCx::new(tcx, typing_env);
307    let mut ecx = InterpCx::new(
308        tcx,
309        rustc_span::DUMMY_SP,
310        typing_env,
311        MiriMachine::new(config, layout_cx, genmc_ctx),
312    );
313
314    // Some parts of initialization require a full `InterpCx`.
315    MiriMachine::late_init(&mut ecx, config, {
316        let mut state = MainThreadState::default();
317        // Cannot capture anything GC-relevant here.
318        Box::new(move |m| state.on_main_stack_empty(m))
319    })?;
320
321    // Make sure we have MIR. We check MIR for some stable monomorphic function in libcore.
322    let sentinel =
323        helpers::try_resolve_path(tcx, &["core", "ascii", "escape_default"], Namespace::ValueNS);
324    if !matches!(sentinel, Some(s) if tcx.is_mir_available(s.def.def_id())) {
325        tcx.dcx().fatal(
326            "the current sysroot was built without `-Zalways-encode-mir`, or libcore seems missing. \
327            Use `cargo miri setup` to prepare a sysroot that is suitable for Miri."
328        );
329    }
330
331    // Setup first stack frame.
332    let entry_instance = ty::Instance::mono(tcx, entry_id);
333
334    // First argument is constructed later, because it's skipped for `miri_start.`
335
336    // Second argument (argc): length of `config.args`.
337    let argc =
338        ImmTy::from_int(i64::try_from(config.args.len()).unwrap(), ecx.machine.layouts.isize);
339    // Third argument (`argv`): created from `config.args`.
340    let argv = {
341        // Put each argument in memory, collect pointers.
342        let mut argvs = Vec::<Immediate<Provenance>>::with_capacity(config.args.len());
343        for arg in config.args.iter() {
344            // Make space for `0` terminator.
345            let size = u64::try_from(arg.len()).unwrap().strict_add(1);
346            let arg_type = Ty::new_array(tcx, tcx.types.u8, size);
347            let arg_place =
348                ecx.allocate(ecx.layout_of(arg_type)?, MiriMemoryKind::Machine.into())?;
349            ecx.write_os_str_to_c_str(OsStr::new(arg), arg_place.ptr(), size)?;
350            ecx.mark_immutable(&arg_place);
351            argvs.push(arg_place.to_ref(&ecx));
352        }
353        // Make an array with all these pointers, in the Miri memory.
354        let argvs_layout = ecx.layout_of(Ty::new_array(
355            tcx,
356            Ty::new_imm_ptr(tcx, tcx.types.u8),
357            u64::try_from(argvs.len()).unwrap(),
358        ))?;
359        let argvs_place = ecx.allocate(argvs_layout, MiriMemoryKind::Machine.into())?;
360        for (idx, arg) in argvs.into_iter().enumerate() {
361            let place = ecx.project_field(&argvs_place, idx)?;
362            ecx.write_immediate(arg, &place)?;
363        }
364        ecx.mark_immutable(&argvs_place);
365        // Store `argc` and `argv` for macOS `_NSGetArg{c,v}`.
366        {
367            let argc_place =
368                ecx.allocate(ecx.machine.layouts.isize, MiriMemoryKind::Machine.into())?;
369            ecx.write_immediate(*argc, &argc_place)?;
370            ecx.mark_immutable(&argc_place);
371            ecx.machine.argc = Some(argc_place.ptr());
372
373            let argv_place = ecx.allocate(
374                ecx.layout_of(Ty::new_imm_ptr(tcx, tcx.types.unit))?,
375                MiriMemoryKind::Machine.into(),
376            )?;
377            ecx.write_pointer(argvs_place.ptr(), &argv_place)?;
378            ecx.mark_immutable(&argv_place);
379            ecx.machine.argv = Some(argv_place.ptr());
380        }
381        // Store command line as UTF-16 for Windows `GetCommandLineW`.
382        {
383            // Construct a command string with all the arguments.
384            let cmd_utf16: Vec<u16> = args_to_utf16_command_string(config.args.iter());
385
386            let cmd_type =
387                Ty::new_array(tcx, tcx.types.u16, u64::try_from(cmd_utf16.len()).unwrap());
388            let cmd_place =
389                ecx.allocate(ecx.layout_of(cmd_type)?, MiriMemoryKind::Machine.into())?;
390            ecx.machine.cmd_line = Some(cmd_place.ptr());
391            // Store the UTF-16 string. We just allocated so we know the bounds are fine.
392            for (idx, &c) in cmd_utf16.iter().enumerate() {
393                let place = ecx.project_field(&cmd_place, idx)?;
394                ecx.write_scalar(Scalar::from_u16(c), &place)?;
395            }
396            ecx.mark_immutable(&cmd_place);
397        }
398        ecx.mplace_to_ref(&argvs_place)?
399    };
400
401    // Return place (in static memory so that it does not count as leak).
402    let ret_place = ecx.allocate(ecx.machine.layouts.isize, MiriMemoryKind::Machine.into())?;
403    ecx.machine.main_fn_ret_place = Some(ret_place.clone());
404    // Call start function.
405
406    match entry_type {
407        MiriEntryFnType::Rustc(EntryFnType::Main { .. }) => {
408            let start_id = tcx.lang_items().start_fn().unwrap_or_else(|| {
409                tcx.dcx().fatal("could not find start lang item");
410            });
411            let main_ret_ty = tcx.fn_sig(entry_id).no_bound_vars().unwrap().output();
412            let main_ret_ty = main_ret_ty.no_bound_vars().unwrap();
413            let start_instance = ty::Instance::try_resolve(
414                tcx,
415                typing_env,
416                start_id,
417                tcx.mk_args(&[ty::GenericArg::from(main_ret_ty)]),
418            )
419            .unwrap()
420            .unwrap();
421
422            let main_ptr = ecx.fn_ptr(FnVal::Instance(entry_instance));
423
424            // Always using DEFAULT is okay since we don't support signals in Miri anyway.
425            // (This means we are effectively ignoring `-Zon-broken-pipe`.)
426            let sigpipe = rustc_session::config::sigpipe::DEFAULT;
427
428            ecx.call_function(
429                start_instance,
430                ExternAbi::Rust,
431                &[
432                    ImmTy::from_scalar(
433                        Scalar::from_pointer(main_ptr, &ecx),
434                        // FIXME use a proper fn ptr type
435                        ecx.machine.layouts.const_raw_ptr,
436                    ),
437                    argc,
438                    argv,
439                    ImmTy::from_uint(sigpipe, ecx.machine.layouts.u8),
440                ],
441                Some(&ret_place),
442                StackPopCleanup::Root { cleanup: true },
443            )?;
444        }
445        MiriEntryFnType::MiriStart => {
446            ecx.call_function(
447                entry_instance,
448                ExternAbi::Rust,
449                &[argc, argv],
450                Some(&ret_place),
451                StackPopCleanup::Root { cleanup: true },
452            )?;
453        }
454    }
455
456    interp_ok(ecx)
457}
458
459/// Evaluates the entry function specified by `entry_id`.
460/// Returns `Some(return_code)` if program execution completed.
461/// Returns `None` if an evaluation error occurred.
462pub fn eval_entry<'tcx>(
463    tcx: TyCtxt<'tcx>,
464    entry_id: DefId,
465    entry_type: MiriEntryFnType,
466    config: &MiriConfig,
467    genmc_ctx: Option<Rc<GenmcCtx>>,
468) -> Option<i32> {
469    // Copy setting before we move `config`.
470    let ignore_leaks = config.ignore_leaks;
471
472    if let Some(genmc_ctx) = &genmc_ctx {
473        genmc_ctx.handle_execution_start();
474    }
475
476    let mut ecx = match create_ecx(tcx, entry_id, entry_type, config, genmc_ctx).report_err() {
477        Ok(v) => v,
478        Err(err) => {
479            let (kind, backtrace) = err.into_parts();
480            backtrace.print_backtrace();
481            panic!("Miri initialization error: {kind:?}")
482        }
483    };
484
485    // Perform the main execution.
486    let res: thread::Result<InterpResult<'_, !>> =
487        panic::catch_unwind(AssertUnwindSafe(|| ecx.run_threads()));
488    let res = res.unwrap_or_else(|panic_payload| {
489        ecx.handle_ice();
490        panic::resume_unwind(panic_payload)
491    });
492    // `Ok` can never happen; the interpreter loop always exits with an "error"
493    // (but that "error" might be just "regular program termination").
494    let Err(err) = res.report_err();
495
496    // Show diagnostic, if any.
497    let (return_code, leak_check) = report_error(&ecx, err)?;
498
499    // We inform GenMC that the execution is complete.
500    if let Some(genmc_ctx) = ecx.machine.data_race.as_genmc_ref()
501        && let Err(error) = genmc_ctx.handle_execution_end(&ecx)
502    {
503        // FIXME(GenMC): Improve error reporting.
504        tcx.dcx().err(format!("GenMC returned an error: \"{error}\""));
505        return None;
506    }
507
508    // If we get here there was no fatal error.
509
510    // Possibly check for memory leaks.
511    if leak_check && !ignore_leaks {
512        // Check for thread leaks.
513        if !ecx.have_all_terminated() {
514            tcx.dcx().err("the main thread terminated without waiting for all remaining threads");
515            tcx.dcx().note("set `MIRIFLAGS=-Zmiri-ignore-leaks` to disable this check");
516            return None;
517        }
518        // Check for memory leaks.
519        info!("Additional static roots: {:?}", ecx.machine.static_roots);
520        let leaks = ecx.take_leaked_allocations(|ecx| &ecx.machine.static_roots);
521        if !leaks.is_empty() {
522            report_leaks(&ecx, leaks);
523            tcx.dcx().note("set `MIRIFLAGS=-Zmiri-ignore-leaks` to disable this check");
524            // Ignore the provided return code - let the reported error
525            // determine the return code.
526            return None;
527        }
528    }
529    Some(return_code)
530}
531
532/// Turns an array of arguments into a Windows command line string.
533///
534/// The string will be UTF-16 encoded and NUL terminated.
535///
536/// Panics if the zeroth argument contains the `"` character because doublequotes
537/// in `argv[0]` cannot be encoded using the standard command line parsing rules.
538///
539/// Further reading:
540/// * [Parsing C++ command-line arguments](https://docs.microsoft.com/en-us/cpp/cpp/main-function-command-line-args?view=msvc-160#parsing-c-command-line-arguments)
541/// * [The C/C++ Parameter Parsing Rules](https://daviddeley.com/autohotkey/parameters/parameters.htm#WINCRULES)
542fn args_to_utf16_command_string<I, T>(mut args: I) -> Vec<u16>
543where
544    I: Iterator<Item = T>,
545    T: AsRef<str>,
546{
547    // Parse argv[0]. Slashes aren't escaped. Literal double quotes are not allowed.
548    let mut cmd = {
549        let arg0 = if let Some(arg0) = args.next() {
550            arg0
551        } else {
552            return vec![0];
553        };
554        let arg0 = arg0.as_ref();
555        if arg0.contains('"') {
556            panic!("argv[0] cannot contain a doublequote (\") character");
557        } else {
558            // Always surround argv[0] with quotes.
559            let mut s = String::new();
560            s.push('"');
561            s.push_str(arg0);
562            s.push('"');
563            s
564        }
565    };
566
567    // Build the other arguments.
568    for arg in args {
569        let arg = arg.as_ref();
570        cmd.push(' ');
571        if arg.is_empty() {
572            cmd.push_str("\"\"");
573        } else if !arg.bytes().any(|c| matches!(c, b'"' | b'\t' | b' ')) {
574            // No quote, tab, or space -- no escaping required.
575            cmd.push_str(arg);
576        } else {
577            // Spaces and tabs are escaped by surrounding them in quotes.
578            // Quotes are themselves escaped by using backslashes when in a
579            // quoted block.
580            // Backslashes only need to be escaped when one or more are directly
581            // followed by a quote. Otherwise they are taken literally.
582
583            cmd.push('"');
584            let mut chars = arg.chars().peekable();
585            loop {
586                let mut nslashes = 0;
587                while let Some(&'\\') = chars.peek() {
588                    chars.next();
589                    nslashes += 1;
590                }
591
592                match chars.next() {
593                    Some('"') => {
594                        cmd.extend(iter::repeat_n('\\', nslashes * 2 + 1));
595                        cmd.push('"');
596                    }
597                    Some(c) => {
598                        cmd.extend(iter::repeat_n('\\', nslashes));
599                        cmd.push(c);
600                    }
601                    None => {
602                        cmd.extend(iter::repeat_n('\\', nslashes * 2));
603                        break;
604                    }
605                }
606            }
607            cmd.push('"');
608        }
609    }
610
611    if cmd.contains('\0') {
612        panic!("interior null in command line arguments");
613    }
614    cmd.encode_utf16().chain(iter::once(0)).collect()
615}
616
617#[cfg(test)]
618mod tests {
619    use super::*;
620    #[test]
621    #[should_panic(expected = "argv[0] cannot contain a doublequote (\") character")]
622    fn windows_argv0_panic_on_quote() {
623        args_to_utf16_command_string(["\""].iter());
624    }
625    #[test]
626    fn windows_argv0_no_escape() {
627        // Ensure that a trailing backslash in argv[0] is not escaped.
628        let cmd = String::from_utf16_lossy(&args_to_utf16_command_string(
629            [r"C:\Program Files\", "arg1", "arg 2", "arg \" 3"].iter(),
630        ));
631        assert_eq!(cmd.trim_end_matches('\0'), r#""C:\Program Files\" arg1 "arg 2" "arg \" 3""#);
632    }
633}
miri/eval.rs

miri/
eval.rs
