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::{HasTyCtxt, HasTypingEnv, LayoutCx};
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::{global_ctor, 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/// Configuration needed to spawn a Miri instance.
36#[derive(Clone)]
37pub struct MiriConfig {
38    /// The host environment snapshot to use as basis for what is provided to the interpreted program.
39    /// (This is still subject to isolation as well as `forwarded_env_vars`.)
40    pub env: Vec<(OsString, OsString)>,
41    /// Determine if validity checking is enabled.
42    pub validation: ValidationMode,
43    /// Determines if Stacked Borrows or Tree Borrows is enabled.
44    pub borrow_tracker: Option<BorrowTrackerMethod>,
45    /// Controls alignment checking.
46    pub check_alignment: AlignmentCheck,
47    /// Action for an op requiring communication with the host.
48    pub isolated_op: IsolatedOp,
49    /// Determines if memory leaks should be ignored.
50    pub ignore_leaks: bool,
51    /// Environment variables that should always be forwarded from the host.
52    pub forwarded_env_vars: Vec<String>,
53    /// Additional environment variables that should be set in the interpreted program.
54    pub set_env_vars: FxHashMap<String, String>,
55    /// Command-line arguments passed to the interpreted program.
56    pub args: Vec<String>,
57    /// The seed to use when non-determinism or randomness are required (e.g. ptr-to-int cast, `getrandom()`).
58    pub seed: Option<u64>,
59    /// The stacked borrows pointer ids to report about.
60    pub tracked_pointer_tags: FxHashSet<BorTag>,
61    /// The allocation ids to report about.
62    pub tracked_alloc_ids: FxHashSet<AllocId>,
63    /// For the tracked alloc ids, also report read/write accesses.
64    pub track_alloc_accesses: bool,
65    /// Determine if data race detection should be enabled.
66    pub data_race_detector: bool,
67    /// Determine if weak memory emulation should be enabled. Requires data race detection to be enabled.
68    pub weak_memory_emulation: bool,
69    /// Determine if we are running in GenMC mode and with which settings. In GenMC mode, Miri will explore multiple concurrent executions of the given program.
70    pub genmc_config: Option<GenmcConfig>,
71    /// Track when an outdated (weak memory) load happens.
72    pub track_outdated_loads: bool,
73    /// Rate of spurious failures for compare_exchange_weak atomic operations,
74    /// between 0.0 and 1.0, defaulting to 0.8 (80% chance of failure).
75    pub cmpxchg_weak_failure_rate: f64,
76    /// If `Some`, enable the `measureme` profiler, writing results to a file
77    /// with the specified prefix.
78    pub measureme_out: Option<String>,
79    /// Which style to use for printing backtraces.
80    pub backtrace_style: BacktraceStyle,
81    /// Which provenance to use for int2ptr casts.
82    pub provenance_mode: ProvenanceMode,
83    /// Whether to ignore any output by the program. This is helpful when debugging miri
84    /// as its messages don't get intermingled with the program messages.
85    pub mute_stdout_stderr: bool,
86    /// The probability of the active thread being preempted at the end of each basic block.
87    pub preemption_rate: f64,
88    /// Report the current instruction being executed every N basic blocks.
89    pub report_progress: Option<u32>,
90    /// Whether Stacked Borrows and Tree Borrows retagging should recurse into fields of datatypes.
91    pub retag_fields: RetagFields,
92    /// The location of the shared object files to load when calling external functions
93    pub native_lib: Vec<PathBuf>,
94    /// Whether to enable the new native lib tracing system.
95    pub native_lib_enable_tracing: bool,
96    /// Run a garbage collector for BorTags every N basic blocks.
97    pub gc_interval: u32,
98    /// The number of CPUs to be reported by miri.
99    pub num_cpus: u32,
100    /// Requires Miri to emulate pages of a certain size.
101    pub page_size: Option<u64>,
102    /// Whether to collect a backtrace when each allocation is created, just in case it leaks.
103    pub collect_leak_backtraces: bool,
104    /// Probability for address reuse.
105    pub address_reuse_rate: f64,
106    /// Probability for address reuse across threads.
107    pub address_reuse_cross_thread_rate: f64,
108    /// Round Robin scheduling with no preemption.
109    pub fixed_scheduling: bool,
110    /// Always prefer the intrinsic fallback body over the native Miri implementation.
111    pub force_intrinsic_fallback: bool,
112    /// Whether floating-point operations can behave non-deterministically.
113    pub float_nondet: bool,
114    /// Whether floating-point operations can have a non-deterministic rounding error.
115    pub float_rounding_error: FloatRoundingErrorMode,
116    /// Whether Miri artifically introduces short reads/writes on file descriptors.
117    pub short_fd_operations: bool,
118}
119
120impl Default for MiriConfig {
121    fn default() -> MiriConfig {
122        MiriConfig {
123            env: vec![],
124            validation: ValidationMode::Shallow,
125            borrow_tracker: Some(BorrowTrackerMethod::StackedBorrows),
126            check_alignment: AlignmentCheck::Int,
127            isolated_op: IsolatedOp::Reject(RejectOpWith::Abort),
128            ignore_leaks: false,
129            forwarded_env_vars: vec![],
130            set_env_vars: FxHashMap::default(),
131            args: vec![],
132            seed: None,
133            tracked_pointer_tags: FxHashSet::default(),
134            tracked_alloc_ids: FxHashSet::default(),
135            track_alloc_accesses: false,
136            data_race_detector: true,
137            weak_memory_emulation: true,
138            genmc_config: None,
139            track_outdated_loads: false,
140            cmpxchg_weak_failure_rate: 0.8, // 80%
141            measureme_out: None,
142            backtrace_style: BacktraceStyle::Short,
143            provenance_mode: ProvenanceMode::Default,
144            mute_stdout_stderr: false,
145            preemption_rate: 0.01, // 1%
146            report_progress: None,
147            retag_fields: RetagFields::Yes,
148            native_lib: vec![],
149            native_lib_enable_tracing: false,
150            gc_interval: 10_000,
151            num_cpus: 1,
152            page_size: None,
153            collect_leak_backtraces: true,
154            address_reuse_rate: 0.5,
155            address_reuse_cross_thread_rate: 0.1,
156            fixed_scheduling: false,
157            force_intrinsic_fallback: false,
158            float_nondet: true,
159            float_rounding_error: FloatRoundingErrorMode::Random,
160            short_fd_operations: true,
161        }
162    }
163}
164
165/// The state of the main thread. Implementation detail of `on_main_stack_empty`.
166#[derive(Debug)]
167enum MainThreadState<'tcx> {
168    GlobalCtors {
169        ctor_state: global_ctor::GlobalCtorState<'tcx>,
170        /// The main function to call.
171        entry_id: DefId,
172        entry_type: MiriEntryFnType,
173        /// Arguments passed to `main`.
174        argc: ImmTy<'tcx>,
175        argv: ImmTy<'tcx>,
176    },
177    Running,
178    TlsDtors(tls::TlsDtorsState<'tcx>),
179    Yield {
180        remaining: u32,
181    },
182    Done,
183}
184
185impl<'tcx> MainThreadState<'tcx> {
186    fn on_main_stack_empty(
187        &mut self,
188        this: &mut MiriInterpCx<'tcx>,
189    ) -> InterpResult<'tcx, Poll<()>> {
190        use MainThreadState::*;
191        match self {
192            GlobalCtors { ctor_state, entry_id, entry_type, argc, argv } => {
193                match ctor_state.on_stack_empty(this)? {
194                    Poll::Pending => {} // just keep going
195                    Poll::Ready(()) => {
196                        call_main(this, *entry_id, *entry_type, argc.clone(), argv.clone())?;
197                        *self = Running;
198                    }
199                }
200            }
201            Running => {
202                *self = TlsDtors(Default::default());
203            }
204            TlsDtors(state) =>
205                match state.on_stack_empty(this)? {
206                    Poll::Pending => {} // just keep going
207                    Poll::Ready(()) => {
208                        if this.machine.data_race.as_genmc_ref().is_some() {
209                            // In GenMC mode, we don't yield at the end of the main thread.
210                            // Instead, the `GenmcCtx` will ensure that unfinished threads get a chance to run at this point.
211                            *self = Done;
212                        } else {
213                            // Give background threads a chance to finish by yielding the main thread a
214                            // couple of times -- but only if we would also preempt threads randomly.
215                            if this.machine.preemption_rate > 0.0 {
216                                // There is a non-zero chance they will yield back to us often enough to
217                                // make Miri terminate eventually.
218                                *self = Yield { remaining: MAIN_THREAD_YIELDS_AT_SHUTDOWN };
219                            } else {
220                                // The other threads did not get preempted, so no need to yield back to
221                                // them.
222                                *self = Done;
223                            }
224                        }
225                    }
226                },
227            Yield { remaining } =>
228                match remaining.checked_sub(1) {
229                    None => *self = Done,
230                    Some(new_remaining) => {
231                        *remaining = new_remaining;
232                        this.yield_active_thread();
233                    }
234                },
235            Done => {
236                // Figure out exit code.
237                let ret_place = this.machine.main_fn_ret_place.clone().unwrap();
238                let exit_code = this.read_target_isize(&ret_place)?;
239                // Rust uses `isize` but the underlying type of an exit code is `i32`.
240                // Do a saturating cast.
241                let exit_code = i32::try_from(exit_code).unwrap_or(if exit_code >= 0 {
242                    i32::MAX
243                } else {
244                    i32::MIN
245                });
246                // Deal with our thread-local memory. We do *not* want to actually free it, instead we consider TLS
247                // to be like a global `static`, so that all memory reached by it is considered to "not leak".
248                this.terminate_active_thread(TlsAllocAction::Leak)?;
249
250                // Stop interpreter loop.
251                throw_machine_stop!(TerminationInfo::Exit { code: exit_code, leak_check: true });
252            }
253        }
254        interp_ok(Poll::Pending)
255    }
256}
257
258/// Returns a freshly created `InterpCx`.
259/// Public because this is also used by `priroda`.
260pub fn create_ecx<'tcx>(
261    tcx: TyCtxt<'tcx>,
262    entry_id: DefId,
263    entry_type: MiriEntryFnType,
264    config: &MiriConfig,
265    genmc_ctx: Option<Rc<GenmcCtx>>,
266) -> InterpResult<'tcx, InterpCx<'tcx, MiriMachine<'tcx>>> {
267    let typing_env = ty::TypingEnv::fully_monomorphized();
268    let layout_cx = LayoutCx::new(tcx, typing_env);
269    let mut ecx = InterpCx::new(
270        tcx,
271        rustc_span::DUMMY_SP,
272        typing_env,
273        MiriMachine::new(config, layout_cx, genmc_ctx),
274    );
275
276    // Make sure we have MIR. We check MIR for some stable monomorphic function in libcore.
277    let sentinel =
278        helpers::try_resolve_path(tcx, &["core", "ascii", "escape_default"], Namespace::ValueNS);
279    if !matches!(sentinel, Some(s) if tcx.is_mir_available(s.def.def_id())) {
280        tcx.dcx().fatal(
281            "the current sysroot was built without `-Zalways-encode-mir`, or libcore seems missing.\n\
282            Note that directly invoking the `miri` binary is not supported; please use `cargo miri` instead."
283        );
284    }
285
286    // Compute argc and argv from `config.args`.
287    let argc =
288        ImmTy::from_int(i64::try_from(config.args.len()).unwrap(), ecx.machine.layouts.isize);
289    let argv = {
290        // Put each argument in memory, collect pointers.
291        let mut argvs = Vec::<Immediate<Provenance>>::with_capacity(config.args.len());
292        for arg in config.args.iter() {
293            // Make space for `0` terminator.
294            let size = u64::try_from(arg.len()).unwrap().strict_add(1);
295            let arg_type = Ty::new_array(tcx, tcx.types.u8, size);
296            let arg_place =
297                ecx.allocate(ecx.layout_of(arg_type)?, MiriMemoryKind::Machine.into())?;
298            ecx.write_os_str_to_c_str(OsStr::new(arg), arg_place.ptr(), size)?;
299            ecx.mark_immutable(&arg_place);
300            argvs.push(arg_place.to_ref(&ecx));
301        }
302        // Make an array with all these pointers, in the Miri memory.
303        let u8_ptr_type = Ty::new_imm_ptr(tcx, tcx.types.u8);
304        let u8_ptr_ptr_type = Ty::new_imm_ptr(tcx, u8_ptr_type);
305        let argvs_layout =
306            ecx.layout_of(Ty::new_array(tcx, u8_ptr_type, u64::try_from(argvs.len()).unwrap()))?;
307        let argvs_place = ecx.allocate(argvs_layout, MiriMemoryKind::Machine.into())?;
308        for (arg, idx) in argvs.into_iter().zip(0..) {
309            let place = ecx.project_index(&argvs_place, idx)?;
310            ecx.write_immediate(arg, &place)?;
311        }
312        ecx.mark_immutable(&argvs_place);
313        // Store `argc` and `argv` for macOS `_NSGetArg{c,v}`, and for the GC to see them.
314        {
315            let argc_place =
316                ecx.allocate(ecx.machine.layouts.isize, MiriMemoryKind::Machine.into())?;
317            ecx.write_immediate(*argc, &argc_place)?;
318            ecx.mark_immutable(&argc_place);
319            ecx.machine.argc = Some(argc_place.ptr());
320
321            let argv_place =
322                ecx.allocate(ecx.layout_of(u8_ptr_ptr_type)?, MiriMemoryKind::Machine.into())?;
323            ecx.write_pointer(argvs_place.ptr(), &argv_place)?;
324            ecx.mark_immutable(&argv_place);
325            ecx.machine.argv = Some(argv_place.ptr());
326        }
327        // Store command line as UTF-16 for Windows `GetCommandLineW`.
328        if tcx.sess.target.os == "windows" {
329            // Construct a command string with all the arguments.
330            let cmd_utf16: Vec<u16> = args_to_utf16_command_string(config.args.iter());
331
332            let cmd_type =
333                Ty::new_array(tcx, tcx.types.u16, u64::try_from(cmd_utf16.len()).unwrap());
334            let cmd_place =
335                ecx.allocate(ecx.layout_of(cmd_type)?, MiriMemoryKind::Machine.into())?;
336            ecx.machine.cmd_line = Some(cmd_place.ptr());
337            // Store the UTF-16 string. We just allocated so we know the bounds are fine.
338            for (&c, idx) in cmd_utf16.iter().zip(0..) {
339                let place = ecx.project_index(&cmd_place, idx)?;
340                ecx.write_scalar(Scalar::from_u16(c), &place)?;
341            }
342            ecx.mark_immutable(&cmd_place);
343        }
344        let imm = argvs_place.to_ref(&ecx);
345        let layout = ecx.layout_of(u8_ptr_ptr_type)?;
346        ImmTy::from_immediate(imm, layout)
347    };
348
349    // Some parts of initialization require a full `InterpCx`.
350    MiriMachine::late_init(&mut ecx, config, {
351        let mut main_thread_state = MainThreadState::GlobalCtors {
352            entry_id,
353            entry_type,
354            argc,
355            argv,
356            ctor_state: global_ctor::GlobalCtorState::default(),
357        };
358
359        // Cannot capture anything GC-relevant here.
360        // `argc` and `argv` *are* GC_relevant, but they also get stored in `machine.argc` and
361        // `machine.argv` so we are good.
362        Box::new(move |m| main_thread_state.on_main_stack_empty(m))
363    })?;
364
365    interp_ok(ecx)
366}
367
368// Call the entry function.
369fn call_main<'tcx>(
370    ecx: &mut MiriInterpCx<'tcx>,
371    entry_id: DefId,
372    entry_type: MiriEntryFnType,
373    argc: ImmTy<'tcx>,
374    argv: ImmTy<'tcx>,
375) -> InterpResult<'tcx, ()> {
376    let tcx = ecx.tcx();
377
378    // Setup first stack frame.
379    let entry_instance = ty::Instance::mono(tcx, entry_id);
380
381    // Return place (in static memory so that it does not count as leak).
382    let ret_place = ecx.allocate(ecx.machine.layouts.isize, MiriMemoryKind::Machine.into())?;
383    ecx.machine.main_fn_ret_place = Some(ret_place.clone());
384
385    // Call start function.
386    match entry_type {
387        MiriEntryFnType::Rustc(EntryFnType::Main { .. }) => {
388            let start_id = tcx.lang_items().start_fn().unwrap_or_else(|| {
389                tcx.dcx().fatal("could not find start lang item");
390            });
391            let main_ret_ty = tcx.fn_sig(entry_id).no_bound_vars().unwrap().output();
392            let main_ret_ty = main_ret_ty.no_bound_vars().unwrap();
393            let start_instance = ty::Instance::try_resolve(
394                tcx,
395                ecx.typing_env(),
396                start_id,
397                tcx.mk_args(&[ty::GenericArg::from(main_ret_ty)]),
398            )
399            .unwrap()
400            .unwrap();
401
402            let main_ptr = ecx.fn_ptr(FnVal::Instance(entry_instance));
403
404            // Always using DEFAULT is okay since we don't support signals in Miri anyway.
405            // (This means we are effectively ignoring `-Zon-broken-pipe`.)
406            let sigpipe = rustc_session::config::sigpipe::DEFAULT;
407
408            ecx.call_function(
409                start_instance,
410                ExternAbi::Rust,
411                &[
412                    ImmTy::from_scalar(
413                        Scalar::from_pointer(main_ptr, ecx),
414                        // FIXME use a proper fn ptr type
415                        ecx.machine.layouts.const_raw_ptr,
416                    ),
417                    argc,
418                    argv,
419                    ImmTy::from_uint(sigpipe, ecx.machine.layouts.u8),
420                ],
421                Some(&ret_place),
422                ReturnContinuation::Stop { cleanup: true },
423            )?;
424        }
425        MiriEntryFnType::MiriStart => {
426            ecx.call_function(
427                entry_instance,
428                ExternAbi::Rust,
429                &[argc, argv],
430                Some(&ret_place),
431                ReturnContinuation::Stop { cleanup: true },
432            )?;
433        }
434    }
435
436    interp_ok(())
437}
438
439/// Evaluates the entry function specified by `entry_id`.
440/// Returns `Some(return_code)` if program execution completed.
441/// Returns `None` if an evaluation error occurred.
442pub fn eval_entry<'tcx>(
443    tcx: TyCtxt<'tcx>,
444    entry_id: DefId,
445    entry_type: MiriEntryFnType,
446    config: &MiriConfig,
447    genmc_ctx: Option<Rc<GenmcCtx>>,
448) -> Option<i32> {
449    // Copy setting before we move `config`.
450    let ignore_leaks = config.ignore_leaks;
451
452    if let Some(genmc_ctx) = &genmc_ctx {
453        genmc_ctx.handle_execution_start();
454    }
455
456    let mut ecx = match create_ecx(tcx, entry_id, entry_type, config, genmc_ctx).report_err() {
457        Ok(v) => v,
458        Err(err) => {
459            let (kind, backtrace) = err.into_parts();
460            backtrace.print_backtrace();
461            panic!("Miri initialization error: {kind:?}")
462        }
463    };
464
465    // Perform the main execution.
466    let res: thread::Result<InterpResult<'_, !>> =
467        panic::catch_unwind(AssertUnwindSafe(|| ecx.run_threads()));
468    let res = res.unwrap_or_else(|panic_payload| {
469        ecx.handle_ice();
470        panic::resume_unwind(panic_payload)
471    });
472    // `Ok` can never happen; the interpreter loop always exits with an "error"
473    // (but that "error" might be just "regular program termination").
474    let Err(err) = res.report_err();
475
476    // Show diagnostic, if any.
477    let (return_code, leak_check) = report_error(&ecx, err)?;
478
479    // We inform GenMC that the execution is complete.
480    if let Some(genmc_ctx) = ecx.machine.data_race.as_genmc_ref()
481        && let Err(error) = genmc_ctx.handle_execution_end(&ecx)
482    {
483        // FIXME(GenMC): Improve error reporting.
484        tcx.dcx().err(format!("GenMC returned an error: \"{error}\""));
485        return None;
486    }
487
488    // If we get here there was no fatal error.
489
490    // Possibly check for memory leaks.
491    if leak_check && !ignore_leaks {
492        // Check for thread leaks.
493        if !ecx.have_all_terminated() {
494            tcx.dcx().err("the main thread terminated without waiting for all remaining threads");
495            tcx.dcx().note("set `MIRIFLAGS=-Zmiri-ignore-leaks` to disable this check");
496            return None;
497        }
498        // Check for memory leaks.
499        info!("Additional static roots: {:?}", ecx.machine.static_roots);
500        let leaks = ecx.take_leaked_allocations(|ecx| &ecx.machine.static_roots);
501        if !leaks.is_empty() {
502            report_leaks(&ecx, leaks);
503            tcx.dcx().note("set `MIRIFLAGS=-Zmiri-ignore-leaks` to disable this check");
504            // Ignore the provided return code - let the reported error
505            // determine the return code.
506            return None;
507        }
508    }
509    Some(return_code)
510}
511
512/// Turns an array of arguments into a Windows command line string.
513///
514/// The string will be UTF-16 encoded and NUL terminated.
515///
516/// Panics if the zeroth argument contains the `"` character because doublequotes
517/// in `argv[0]` cannot be encoded using the standard command line parsing rules.
518///
519/// Further reading:
520/// * [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)
521/// * [The C/C++ Parameter Parsing Rules](https://daviddeley.com/autohotkey/parameters/parameters.htm#WINCRULES)
522fn args_to_utf16_command_string<I, T>(mut args: I) -> Vec<u16>
523where
524    I: Iterator<Item = T>,
525    T: AsRef<str>,
526{
527    // Parse argv[0]. Slashes aren't escaped. Literal double quotes are not allowed.
528    let mut cmd = {
529        let arg0 = if let Some(arg0) = args.next() {
530            arg0
531        } else {
532            return vec![0];
533        };
534        let arg0 = arg0.as_ref();
535        if arg0.contains('"') {
536            panic!("argv[0] cannot contain a doublequote (\") character");
537        } else {
538            // Always surround argv[0] with quotes.
539            let mut s = String::new();
540            s.push('"');
541            s.push_str(arg0);
542            s.push('"');
543            s
544        }
545    };
546
547    // Build the other arguments.
548    for arg in args {
549        let arg = arg.as_ref();
550        cmd.push(' ');
551        if arg.is_empty() {
552            cmd.push_str("\"\"");
553        } else if !arg.bytes().any(|c| matches!(c, b'"' | b'\t' | b' ')) {
554            // No quote, tab, or space -- no escaping required.
555            cmd.push_str(arg);
556        } else {
557            // Spaces and tabs are escaped by surrounding them in quotes.
558            // Quotes are themselves escaped by using backslashes when in a
559            // quoted block.
560            // Backslashes only need to be escaped when one or more are directly
561            // followed by a quote. Otherwise they are taken literally.
562
563            cmd.push('"');
564            let mut chars = arg.chars().peekable();
565            loop {
566                let mut nslashes = 0;
567                while let Some(&'\\') = chars.peek() {
568                    chars.next();
569                    nslashes += 1;
570                }
571
572                match chars.next() {
573                    Some('"') => {
574                        cmd.extend(iter::repeat_n('\\', nslashes * 2 + 1));
575                        cmd.push('"');
576                    }
577                    Some(c) => {
578                        cmd.extend(iter::repeat_n('\\', nslashes));
579                        cmd.push(c);
580                    }
581                    None => {
582                        cmd.extend(iter::repeat_n('\\', nslashes * 2));
583                        break;
584                    }
585                }
586            }
587            cmd.push('"');
588        }
589    }
590
591    if cmd.contains('\0') {
592        panic!("interior null in command line arguments");
593    }
594    cmd.encode_utf16().chain(iter::once(0)).collect()
595}
596
597#[cfg(test)]
598mod tests {
599    use super::*;
600    #[test]
601    #[should_panic(expected = "argv[0] cannot contain a doublequote (\") character")]
602    fn windows_argv0_panic_on_quote() {
603        args_to_utf16_command_string(["\""].iter());
604    }
605    #[test]
606    fn windows_argv0_no_escape() {
607        // Ensure that a trailing backslash in argv[0] is not escaped.
608        let cmd = String::from_utf16_lossy(&args_to_utf16_command_string(
609            [r"C:\Program Files\", "arg1", "arg 2", "arg \" 3"].iter(),
610        ));
611        assert_eq!(cmd.trim_end_matches('\0'), r#""C:\Program Files\" arg1 "arg 2" "arg \" 3""#);
612    }
613}
miri/eval.rs

miri/
eval.rs
