| //! Main evaluator loop and setting up the initial stack frame. |
| |
| use std::ffi::{OsStr, OsString}; |
| use std::panic::{self, AssertUnwindSafe}; |
| use std::path::PathBuf; |
| use std::task::Poll; |
| use std::{iter, thread}; |
| |
| use rustc_data_structures::fx::{FxHashMap, FxHashSet}; |
| use rustc_hir::def::Namespace; |
| use rustc_hir::def_id::DefId; |
| use rustc_middle::ty::layout::{LayoutCx, LayoutOf}; |
| use rustc_middle::ty::{self, Ty, TyCtxt}; |
| use rustc_session::config::EntryFnType; |
| use rustc_target::spec::abi::Abi; |
| |
| use crate::concurrency::thread::TlsAllocAction; |
| use crate::diagnostics::report_leaks; |
| use crate::shims::tls; |
| use crate::*; |
| |
| /// When the main thread would exit, we will yield to any other thread that is ready to execute. |
| /// But we must only do that a finite number of times, or a background thread running `loop {}` |
| /// will hang the program. |
| const MAIN_THREAD_YIELDS_AT_SHUTDOWN: u32 = 256; |
| |
| #[derive(Copy, Clone, Debug, PartialEq)] |
| pub enum AlignmentCheck { |
| /// Do not check alignment. |
| None, |
| /// Check alignment "symbolically", i.e., using only the requested alignment for an allocation and not its real base address. |
| Symbolic, |
| /// Check alignment on the actual physical integer address. |
| Int, |
| } |
| |
| #[derive(Copy, Clone, Debug, PartialEq)] |
| pub enum RejectOpWith { |
| /// Isolated op is rejected with an abort of the machine. |
| Abort, |
| |
| /// If not Abort, miri returns an error for an isolated op. |
| /// Following options determine if user should be warned about such error. |
| /// Do not print warning about rejected isolated op. |
| NoWarning, |
| |
| /// Print a warning about rejected isolated op, with backtrace. |
| Warning, |
| |
| /// Print a warning about rejected isolated op, without backtrace. |
| WarningWithoutBacktrace, |
| } |
| |
| #[derive(Copy, Clone, Debug, PartialEq)] |
| pub enum IsolatedOp { |
| /// Reject an op requiring communication with the host. By |
| /// default, miri rejects the op with an abort. If not, it returns |
| /// an error code, and prints a warning about it. Warning levels |
| /// are controlled by `RejectOpWith` enum. |
| Reject(RejectOpWith), |
| |
| /// Execute op requiring communication with the host, i.e. disable isolation. |
| Allow, |
| } |
| |
| #[derive(Debug, Copy, Clone, PartialEq, Eq)] |
| pub enum BacktraceStyle { |
| /// Prints a terser backtrace which ideally only contains relevant information. |
| Short, |
| /// Prints a backtrace with all possible information. |
| Full, |
| /// Prints only the frame that the error occurs in. |
| Off, |
| } |
| |
| #[derive(Debug, Copy, Clone, PartialEq, Eq)] |
| pub enum ValidationMode { |
| /// Do not perform any kind of validation. |
| No, |
| /// Validate the interior of the value, but not things behind references. |
| Shallow, |
| /// Fully recursively validate references. |
| Deep, |
| } |
| |
| /// Configuration needed to spawn a Miri instance. |
| #[derive(Clone)] |
| pub struct MiriConfig { |
| /// The host environment snapshot to use as basis for what is provided to the interpreted program. |
| /// (This is still subject to isolation as well as `forwarded_env_vars`.) |
| pub env: Vec<(OsString, OsString)>, |
| /// Determine if validity checking is enabled. |
| pub validation: ValidationMode, |
| /// Determines if Stacked Borrows or Tree Borrows is enabled. |
| pub borrow_tracker: Option<BorrowTrackerMethod>, |
| /// Whether `core::ptr::Unique` receives special treatment. |
| /// If `true` then `Unique` is reborrowed with its own new tag and permission, |
| /// otherwise `Unique` is just another raw pointer. |
| pub unique_is_unique: bool, |
| /// Controls alignment checking. |
| pub check_alignment: AlignmentCheck, |
| /// Action for an op requiring communication with the host. |
| pub isolated_op: IsolatedOp, |
| /// Determines if memory leaks should be ignored. |
| pub ignore_leaks: bool, |
| /// Environment variables that should always be forwarded from the host. |
| pub forwarded_env_vars: Vec<String>, |
| /// Additional environment variables that should be set in the interpreted program. |
| pub set_env_vars: FxHashMap<String, String>, |
| /// Command-line arguments passed to the interpreted program. |
| pub args: Vec<String>, |
| /// The seed to use when non-determinism or randomness are required (e.g. ptr-to-int cast, `getrandom()`). |
| pub seed: Option<u64>, |
| /// The stacked borrows pointer ids to report about |
| pub tracked_pointer_tags: FxHashSet<BorTag>, |
| /// The allocation ids to report about. |
| pub tracked_alloc_ids: FxHashSet<AllocId>, |
| /// For the tracked alloc ids, also report read/write accesses. |
| pub track_alloc_accesses: bool, |
| /// Determine if data race detection should be enabled |
| pub data_race_detector: bool, |
| /// Determine if weak memory emulation should be enabled. Requires data race detection to be enabled |
| pub weak_memory_emulation: bool, |
| /// Track when an outdated (weak memory) load happens. |
| pub track_outdated_loads: bool, |
| /// Rate of spurious failures for compare_exchange_weak atomic operations, |
| /// between 0.0 and 1.0, defaulting to 0.8 (80% chance of failure). |
| pub cmpxchg_weak_failure_rate: f64, |
| /// If `Some`, enable the `measureme` profiler, writing results to a file |
| /// with the specified prefix. |
| pub measureme_out: Option<String>, |
| /// Which style to use for printing backtraces. |
| pub backtrace_style: BacktraceStyle, |
| /// Which provenance to use for int2ptr casts |
| pub provenance_mode: ProvenanceMode, |
| /// Whether to ignore any output by the program. This is helpful when debugging miri |
| /// as its messages don't get intermingled with the program messages. |
| pub mute_stdout_stderr: bool, |
| /// The probability of the active thread being preempted at the end of each basic block. |
| pub preemption_rate: f64, |
| /// Report the current instruction being executed every N basic blocks. |
| pub report_progress: Option<u32>, |
| /// Whether Stacked Borrows and Tree Borrows retagging should recurse into fields of datatypes. |
| pub retag_fields: RetagFields, |
| /// The location of a shared object file to load when calling external functions |
| /// FIXME! consider allowing users to specify paths to multiple files, or to a directory |
| pub native_lib: Option<PathBuf>, |
| /// Run a garbage collector for BorTags every N basic blocks. |
| pub gc_interval: u32, |
| /// The number of CPUs to be reported by miri. |
| pub num_cpus: u32, |
| /// Requires Miri to emulate pages of a certain size |
| pub page_size: Option<u64>, |
| /// Whether to collect a backtrace when each allocation is created, just in case it leaks. |
| pub collect_leak_backtraces: bool, |
| /// Probability for address reuse. |
| pub address_reuse_rate: f64, |
| /// Probability for address reuse across threads. |
| pub address_reuse_cross_thread_rate: f64, |
| } |
| |
| impl Default for MiriConfig { |
| fn default() -> MiriConfig { |
| MiriConfig { |
| env: vec![], |
| validation: ValidationMode::Shallow, |
| borrow_tracker: Some(BorrowTrackerMethod::StackedBorrows), |
| unique_is_unique: false, |
| check_alignment: AlignmentCheck::Int, |
| isolated_op: IsolatedOp::Reject(RejectOpWith::Abort), |
| ignore_leaks: false, |
| forwarded_env_vars: vec![], |
| set_env_vars: FxHashMap::default(), |
| args: vec![], |
| seed: None, |
| tracked_pointer_tags: FxHashSet::default(), |
| tracked_alloc_ids: FxHashSet::default(), |
| track_alloc_accesses: false, |
| data_race_detector: true, |
| weak_memory_emulation: true, |
| track_outdated_loads: false, |
| cmpxchg_weak_failure_rate: 0.8, // 80% |
| measureme_out: None, |
| backtrace_style: BacktraceStyle::Short, |
| provenance_mode: ProvenanceMode::Default, |
| mute_stdout_stderr: false, |
| preemption_rate: 0.01, // 1% |
| report_progress: None, |
| retag_fields: RetagFields::Yes, |
| native_lib: None, |
| gc_interval: 10_000, |
| num_cpus: 1, |
| page_size: None, |
| collect_leak_backtraces: true, |
| address_reuse_rate: 0.5, |
| address_reuse_cross_thread_rate: 0.1, |
| } |
| } |
| } |
| |
| /// The state of the main thread. Implementation detail of `on_main_stack_empty`. |
| #[derive(Default, Debug)] |
| enum MainThreadState<'tcx> { |
| #[default] |
| Running, |
| TlsDtors(tls::TlsDtorsState<'tcx>), |
| Yield { |
| remaining: u32, |
| }, |
| Done, |
| } |
| |
| impl<'tcx> MainThreadState<'tcx> { |
| fn on_main_stack_empty( |
| &mut self, |
| this: &mut MiriInterpCx<'tcx>, |
| ) -> InterpResult<'tcx, Poll<()>> { |
| use MainThreadState::*; |
| match self { |
| Running => { |
| *self = TlsDtors(Default::default()); |
| } |
| TlsDtors(state) => |
| match state.on_stack_empty(this)? { |
| Poll::Pending => {} // just keep going |
| Poll::Ready(()) => { |
| // Give background threads a chance to finish by yielding the main thread a |
| // couple of times -- but only if we would also preempt threads randomly. |
| if this.machine.preemption_rate > 0.0 { |
| // There is a non-zero chance they will yield back to us often enough to |
| // make Miri terminate eventually. |
| *self = Yield { remaining: MAIN_THREAD_YIELDS_AT_SHUTDOWN }; |
| } else { |
| // The other threads did not get preempted, so no need to yield back to |
| // them. |
| *self = Done; |
| } |
| } |
| }, |
| Yield { remaining } => |
| match remaining.checked_sub(1) { |
| None => *self = Done, |
| Some(new_remaining) => { |
| *remaining = new_remaining; |
| this.yield_active_thread(); |
| } |
| }, |
| Done => { |
| // Figure out exit code. |
| let ret_place = this.machine.main_fn_ret_place.clone().unwrap(); |
| let exit_code = this.read_target_isize(&ret_place)?; |
| // Deal with our thread-local memory. We do *not* want to actually free it, instead we consider TLS |
| // to be like a global `static`, so that all memory reached by it is considered to "not leak". |
| this.terminate_active_thread(TlsAllocAction::Leak)?; |
| // Stop interpreter loop. |
| throw_machine_stop!(TerminationInfo::Exit { code: exit_code, leak_check: true }); |
| } |
| } |
| interp_ok(Poll::Pending) |
| } |
| } |
| |
| /// Returns a freshly created `InterpCx`. |
| /// Public because this is also used by `priroda`. |
| pub fn create_ecx<'tcx>( |
| tcx: TyCtxt<'tcx>, |
| entry_id: DefId, |
| entry_type: EntryFnType, |
| config: &MiriConfig, |
| ) -> InterpResult<'tcx, InterpCx<'tcx, MiriMachine<'tcx>>> { |
| let param_env = ty::ParamEnv::reveal_all(); |
| let layout_cx = LayoutCx::new(tcx, param_env); |
| let mut ecx = |
| InterpCx::new(tcx, rustc_span::DUMMY_SP, param_env, MiriMachine::new(config, layout_cx)); |
| |
| // Some parts of initialization require a full `InterpCx`. |
| MiriMachine::late_init(&mut ecx, config, { |
| let mut state = MainThreadState::default(); |
| // Cannot capture anything GC-relevant here. |
| Box::new(move |m| state.on_main_stack_empty(m)) |
| })?; |
| |
| // Make sure we have MIR. We check MIR for some stable monomorphic function in libcore. |
| let sentinel = |
| helpers::try_resolve_path(tcx, &["core", "ascii", "escape_default"], Namespace::ValueNS); |
| if !matches!(sentinel, Some(s) if tcx.is_mir_available(s.def.def_id())) { |
| tcx.dcx().fatal( |
| "the current sysroot was built without `-Zalways-encode-mir`, or libcore seems missing. \ |
| Use `cargo miri setup` to prepare a sysroot that is suitable for Miri." |
| ); |
| } |
| |
| // Setup first stack frame. |
| let entry_instance = ty::Instance::mono(tcx, entry_id); |
| |
| // First argument is constructed later, because it's skipped if the entry function uses #[start]. |
| |
| // Second argument (argc): length of `config.args`. |
| let argc = |
| ImmTy::from_int(i64::try_from(config.args.len()).unwrap(), ecx.machine.layouts.isize); |
| // Third argument (`argv`): created from `config.args`. |
| let argv = { |
| // Put each argument in memory, collect pointers. |
| let mut argvs = Vec::<Immediate<Provenance>>::with_capacity(config.args.len()); |
| for arg in config.args.iter() { |
| // Make space for `0` terminator. |
| let size = u64::try_from(arg.len()).unwrap().strict_add(1); |
| let arg_type = Ty::new_array(tcx, tcx.types.u8, size); |
| let arg_place = |
| ecx.allocate(ecx.layout_of(arg_type)?, MiriMemoryKind::Machine.into())?; |
| ecx.write_os_str_to_c_str(OsStr::new(arg), arg_place.ptr(), size)?; |
| ecx.mark_immutable(&arg_place); |
| argvs.push(arg_place.to_ref(&ecx)); |
| } |
| // Make an array with all these pointers, in the Miri memory. |
| let argvs_layout = ecx.layout_of(Ty::new_array( |
| tcx, |
| Ty::new_imm_ptr(tcx, tcx.types.u8), |
| u64::try_from(argvs.len()).unwrap(), |
| ))?; |
| let argvs_place = ecx.allocate(argvs_layout, MiriMemoryKind::Machine.into())?; |
| for (idx, arg) in argvs.into_iter().enumerate() { |
| let place = ecx.project_field(&argvs_place, idx)?; |
| ecx.write_immediate(arg, &place)?; |
| } |
| ecx.mark_immutable(&argvs_place); |
| // Store `argc` and `argv` for macOS `_NSGetArg{c,v}`. |
| { |
| let argc_place = |
| ecx.allocate(ecx.machine.layouts.isize, MiriMemoryKind::Machine.into())?; |
| ecx.write_immediate(*argc, &argc_place)?; |
| ecx.mark_immutable(&argc_place); |
| ecx.machine.argc = Some(argc_place.ptr()); |
| |
| let argv_place = ecx.allocate( |
| ecx.layout_of(Ty::new_imm_ptr(tcx, tcx.types.unit))?, |
| MiriMemoryKind::Machine.into(), |
| )?; |
| ecx.write_pointer(argvs_place.ptr(), &argv_place)?; |
| ecx.mark_immutable(&argv_place); |
| ecx.machine.argv = Some(argv_place.ptr()); |
| } |
| // Store command line as UTF-16 for Windows `GetCommandLineW`. |
| { |
| // Construct a command string with all the arguments. |
| let cmd_utf16: Vec<u16> = args_to_utf16_command_string(config.args.iter()); |
| |
| let cmd_type = |
| Ty::new_array(tcx, tcx.types.u16, u64::try_from(cmd_utf16.len()).unwrap()); |
| let cmd_place = |
| ecx.allocate(ecx.layout_of(cmd_type)?, MiriMemoryKind::Machine.into())?; |
| ecx.machine.cmd_line = Some(cmd_place.ptr()); |
| // Store the UTF-16 string. We just allocated so we know the bounds are fine. |
| for (idx, &c) in cmd_utf16.iter().enumerate() { |
| let place = ecx.project_field(&cmd_place, idx)?; |
| ecx.write_scalar(Scalar::from_u16(c), &place)?; |
| } |
| ecx.mark_immutable(&cmd_place); |
| } |
| ecx.mplace_to_ref(&argvs_place)? |
| }; |
| |
| // Return place (in static memory so that it does not count as leak). |
| let ret_place = ecx.allocate(ecx.machine.layouts.isize, MiriMemoryKind::Machine.into())?; |
| ecx.machine.main_fn_ret_place = Some(ret_place.clone()); |
| // Call start function. |
| |
| match entry_type { |
| EntryFnType::Main { .. } => { |
| let start_id = tcx.lang_items().start_fn().unwrap_or_else(|| { |
| tcx.dcx().fatal( |
| "could not find start function. Make sure the entry point is marked with `#[start]`." |
| ); |
| }); |
| let main_ret_ty = tcx.fn_sig(entry_id).no_bound_vars().unwrap().output(); |
| let main_ret_ty = main_ret_ty.no_bound_vars().unwrap(); |
| let start_instance = ty::Instance::try_resolve( |
| tcx, |
| ty::ParamEnv::reveal_all(), |
| start_id, |
| tcx.mk_args(&[ty::GenericArg::from(main_ret_ty)]), |
| ) |
| .unwrap() |
| .unwrap(); |
| |
| let main_ptr = ecx.fn_ptr(FnVal::Instance(entry_instance)); |
| |
| // Always using DEFAULT is okay since we don't support signals in Miri anyway. |
| // (This means we are effectively ignoring `-Zon-broken-pipe`.) |
| let sigpipe = rustc_session::config::sigpipe::DEFAULT; |
| |
| ecx.call_function( |
| start_instance, |
| Abi::Rust, |
| &[ |
| ImmTy::from_scalar( |
| Scalar::from_pointer(main_ptr, &ecx), |
| // FIXME use a proper fn ptr type |
| ecx.machine.layouts.const_raw_ptr, |
| ), |
| argc, |
| argv, |
| ImmTy::from_uint(sigpipe, ecx.machine.layouts.u8), |
| ], |
| Some(&ret_place), |
| StackPopCleanup::Root { cleanup: true }, |
| )?; |
| } |
| EntryFnType::Start => { |
| ecx.call_function( |
| entry_instance, |
| Abi::Rust, |
| &[argc, argv], |
| Some(&ret_place), |
| StackPopCleanup::Root { cleanup: true }, |
| )?; |
| } |
| } |
| |
| interp_ok(ecx) |
| } |
| |
| /// Evaluates the entry function specified by `entry_id`. |
| /// Returns `Some(return_code)` if program executed completed. |
| /// Returns `None` if an evaluation error occurred. |
| #[allow(clippy::needless_lifetimes)] |
| pub fn eval_entry<'tcx>( |
| tcx: TyCtxt<'tcx>, |
| entry_id: DefId, |
| entry_type: EntryFnType, |
| config: MiriConfig, |
| ) -> Option<i64> { |
| // Copy setting before we move `config`. |
| let ignore_leaks = config.ignore_leaks; |
| |
| let mut ecx = match create_ecx(tcx, entry_id, entry_type, &config).report_err() { |
| Ok(v) => v, |
| Err(err) => { |
| let (kind, backtrace) = err.into_parts(); |
| backtrace.print_backtrace(); |
| panic!("Miri initialization error: {kind:?}") |
| } |
| }; |
| |
| // Perform the main execution. |
| let res: thread::Result<InterpResult<'_, !>> = |
| panic::catch_unwind(AssertUnwindSafe(|| ecx.run_threads())); |
| let res = res.unwrap_or_else(|panic_payload| { |
| ecx.handle_ice(); |
| panic::resume_unwind(panic_payload) |
| }); |
| // `Ok` can never happen. |
| let Err(err) = res.report_err(); |
| |
| // Machine cleanup. Only do this if all threads have terminated; threads that are still running |
| // might cause Stacked Borrows errors (https://github.com/rust-lang/miri/issues/2396). |
| if ecx.have_all_terminated() { |
| // Even if all threads have terminated, we have to beware of data races since some threads |
| // might not have joined the main thread (https://github.com/rust-lang/miri/issues/2020, |
| // https://github.com/rust-lang/miri/issues/2508). |
| ecx.allow_data_races_all_threads_done(); |
| EnvVars::cleanup(&mut ecx).expect("error during env var cleanup"); |
| } |
| |
| // Process the result. |
| let (return_code, leak_check) = report_error(&ecx, err)?; |
| if leak_check && !ignore_leaks { |
| // Check for thread leaks. |
| if !ecx.have_all_terminated() { |
| tcx.dcx().err("the main thread terminated without waiting for all remaining threads"); |
| tcx.dcx().note("set `MIRIFLAGS=-Zmiri-ignore-leaks` to disable this check"); |
| return None; |
| } |
| // Check for memory leaks. |
| info!("Additional static roots: {:?}", ecx.machine.static_roots); |
| let leaks = ecx.take_leaked_allocations(|ecx| &ecx.machine.static_roots); |
| if !leaks.is_empty() { |
| report_leaks(&ecx, leaks); |
| tcx.dcx().note("set `MIRIFLAGS=-Zmiri-ignore-leaks` to disable this check"); |
| // Ignore the provided return code - let the reported error |
| // determine the return code. |
| return None; |
| } |
| } |
| Some(return_code) |
| } |
| |
| /// Turns an array of arguments into a Windows command line string. |
| /// |
| /// The string will be UTF-16 encoded and NUL terminated. |
| /// |
| /// Panics if the zeroth argument contains the `"` character because doublequotes |
| /// in `argv[0]` cannot be encoded using the standard command line parsing rules. |
| /// |
| /// Further reading: |
| /// * [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) |
| /// * [The C/C++ Parameter Parsing Rules](https://daviddeley.com/autohotkey/parameters/parameters.htm#WINCRULES) |
| fn args_to_utf16_command_string<I, T>(mut args: I) -> Vec<u16> |
| where |
| I: Iterator<Item = T>, |
| T: AsRef<str>, |
| { |
| // Parse argv[0]. Slashes aren't escaped. Literal double quotes are not allowed. |
| let mut cmd = { |
| let arg0 = if let Some(arg0) = args.next() { |
| arg0 |
| } else { |
| return vec![0]; |
| }; |
| let arg0 = arg0.as_ref(); |
| if arg0.contains('"') { |
| panic!("argv[0] cannot contain a doublequote (\") character"); |
| } else { |
| // Always surround argv[0] with quotes. |
| let mut s = String::new(); |
| s.push('"'); |
| s.push_str(arg0); |
| s.push('"'); |
| s |
| } |
| }; |
| |
| // Build the other arguments. |
| for arg in args { |
| let arg = arg.as_ref(); |
| cmd.push(' '); |
| if arg.is_empty() { |
| cmd.push_str("\"\""); |
| } else if !arg.bytes().any(|c| matches!(c, b'"' | b'\t' | b' ')) { |
| // No quote, tab, or space -- no escaping required. |
| cmd.push_str(arg); |
| } else { |
| // Spaces and tabs are escaped by surrounding them in quotes. |
| // Quotes are themselves escaped by using backslashes when in a |
| // quoted block. |
| // Backslashes only need to be escaped when one or more are directly |
| // followed by a quote. Otherwise they are taken literally. |
| |
| cmd.push('"'); |
| let mut chars = arg.chars().peekable(); |
| loop { |
| let mut nslashes = 0; |
| while let Some(&'\\') = chars.peek() { |
| chars.next(); |
| nslashes += 1; |
| } |
| |
| match chars.next() { |
| Some('"') => { |
| cmd.extend(iter::repeat('\\').take(nslashes * 2 + 1)); |
| cmd.push('"'); |
| } |
| Some(c) => { |
| cmd.extend(iter::repeat('\\').take(nslashes)); |
| cmd.push(c); |
| } |
| None => { |
| cmd.extend(iter::repeat('\\').take(nslashes * 2)); |
| break; |
| } |
| } |
| } |
| cmd.push('"'); |
| } |
| } |
| |
| if cmd.contains('\0') { |
| panic!("interior null in command line arguments"); |
| } |
| cmd.encode_utf16().chain(iter::once(0)).collect() |
| } |
| |
| #[cfg(test)] |
| mod tests { |
| use super::*; |
| #[test] |
| #[should_panic(expected = "argv[0] cannot contain a doublequote (\") character")] |
| fn windows_argv0_panic_on_quote() { |
| args_to_utf16_command_string(["\""].iter()); |
| } |
| #[test] |
| fn windows_argv0_no_escape() { |
| // Ensure that a trailing backslash in argv[0] is not escaped. |
| let cmd = String::from_utf16_lossy(&args_to_utf16_command_string( |
| [r"C:\Program Files\", "arg1", "arg 2", "arg \" 3"].iter(), |
| )); |
| assert_eq!(cmd.trim_end_matches('\0'), r#""C:\Program Files\" arg1 "arg 2" "arg \" 3""#); |
| } |
| } |
