//! Main evaluator loop and setting up the initial stack frame. use std::convert::TryFrom; use std::ffi::OsStr; use log::info; use rustc_hir::def_id::DefId; use rustc_middle::ty::{self, layout::LayoutCx, TyCtxt}; use rustc_target::abi::LayoutOf; use rustc_target::spec::abi::Abi; use crate::*; #[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, } /// Configuration needed to spawn a Miri instance. #[derive(Clone)] pub struct MiriConfig { /// Determine if validity checking is enabled. pub validate: bool, /// Determines if Stacked Borrows is enabled. pub stacked_borrows: bool, /// Controls alignment checking. pub check_alignment: AlignmentCheck, /// Controls function [ABI](Abi) checking. pub check_abi: bool, /// 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 isolated from the host. pub excluded_env_vars: Vec, /// Command-line arguments passed to the interpreted program. pub args: Vec, /// The seed to use when non-determinism or randomness are required (e.g. ptr-to-int cast, `getrandom()`). pub seed: Option, /// The stacked borrows pointer id to report about pub tracked_pointer_tag: Option, /// The stacked borrows call ID to report about pub tracked_call_id: Option, /// The allocation id to report about. pub tracked_alloc_id: Option, /// Whether to track raw pointers in stacked borrows. pub track_raw: bool, /// Determine if data race detection should be enabled pub data_race_detector: 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, /// Panic when unsupported functionality is encountered pub panic_on_unsupported: bool, } impl Default for MiriConfig { fn default() -> MiriConfig { MiriConfig { validate: true, stacked_borrows: true, check_alignment: AlignmentCheck::Int, check_abi: true, isolated_op: IsolatedOp::Reject(RejectOpWith::Abort), ignore_leaks: false, excluded_env_vars: vec![], args: vec![], seed: None, tracked_pointer_tag: None, tracked_call_id: None, tracked_alloc_id: None, track_raw: false, data_race_detector: true, cmpxchg_weak_failure_rate: 0.8, measureme_out: None, panic_on_unsupported: false, } } } /// Returns a freshly created `InterpCx`, along with an `MPlaceTy` representing /// the location where the return value of the `start` lang item will be /// written to. /// Public because this is also used by `priroda`. pub fn create_ecx<'mir, 'tcx: 'mir>( tcx: TyCtxt<'tcx>, main_id: DefId, config: MiriConfig, ) -> InterpResult<'tcx, (InterpCx<'mir, 'tcx, Evaluator<'mir, 'tcx>>, MPlaceTy<'tcx, Tag>)> { let param_env = ty::ParamEnv::reveal_all(); let layout_cx = LayoutCx { tcx, param_env }; let mut ecx = InterpCx::new( tcx, rustc_span::source_map::DUMMY_SP, param_env, Evaluator::new(&config, layout_cx), MemoryExtra::new(&config), ); // Complete initialization. EnvVars::init(&mut ecx, config.excluded_env_vars)?; MemoryExtra::init_extern_statics(&mut ecx)?; // Make sure we have MIR. We check MIR for some stable monomorphic function in libcore. let sentinel = ecx.resolve_path(&["core", "ascii", "escape_default"]); if !tcx.is_mir_available(sentinel.def.def_id()) { tcx.sess.fatal("the current sysroot was built without `-Zalways-encode-mir`. Use `cargo miri setup` to prepare a sysroot that is suitable for Miri."); } // Setup first stack-frame let main_instance = ty::Instance::mono(tcx, main_id); let main_mir = ecx.load_mir(main_instance.def, None)?; if main_mir.arg_count != 0 { bug!("main function must not take any arguments"); } let start_id = tcx.lang_items().start_fn().unwrap(); let main_ret_ty = tcx.fn_sig(main_id).output(); let main_ret_ty = main_ret_ty.no_bound_vars().unwrap(); let start_instance = ty::Instance::resolve( tcx, ty::ParamEnv::reveal_all(), start_id, tcx.mk_substs(::std::iter::once(ty::subst::GenericArg::from(main_ret_ty))), ) .unwrap() .unwrap(); // First argument: pointer to `main()`. let main_ptr = ecx.memory.create_fn_alloc(FnVal::Instance(main_instance)); // Second argument (argc): length of `config.args`. let argc = Scalar::from_machine_usize(u64::try_from(config.args.len()).unwrap(), &ecx); // Third argument (`argv`): created from `config.args`. let argv = { // Put each argument in memory, collect pointers. let mut argvs = Vec::>::new(); for arg in config.args.iter() { // Make space for `0` terminator. let size = u64::try_from(arg.len()).unwrap().checked_add(1).unwrap(); let arg_type = tcx.mk_array(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( tcx.mk_array(tcx.mk_imm_ptr(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.mplace_field(&argvs_place, idx)?; ecx.write_immediate(arg, &place.into())?; } ecx.mark_immutable(&*argvs_place); // A pointer to that place is the 3rd argument for main. let argv = argvs_place.to_ref(&ecx); // Store `argc` and `argv` for macOS `_NSGetArg{c,v}`. { let argc_place = ecx.allocate(ecx.machine.layouts.isize, MiriMemoryKind::Machine.into())?; ecx.write_scalar(argc, &argc_place.into())?; ecx.mark_immutable(&*argc_place); ecx.machine.argc = Some(*argc_place); let argv_place = ecx.allocate( ecx.layout_of(tcx.mk_imm_ptr(tcx.types.unit))?, MiriMemoryKind::Machine.into(), )?; ecx.write_immediate(argv, &argv_place.into())?; ecx.mark_immutable(&*argv_place); ecx.machine.argv = Some(*argv_place); } // Store command line as UTF-16 for Windows `GetCommandLineW`. { // Construct a command string with all the aguments. let mut cmd = String::new(); for arg in config.args.iter() { if !cmd.is_empty() { cmd.push(' '); } cmd.push_str(&*shell_escape::windows::escape(arg.as_str().into())); } // Don't forget `0` terminator. cmd.push(std::char::from_u32(0).unwrap()); let cmd_utf16: Vec = cmd.encode_utf16().collect(); let cmd_type = tcx.mk_array(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); // 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.mplace_field(&cmd_place, idx)?; ecx.write_scalar(Scalar::from_u16(c), &place.into())?; } ecx.mark_immutable(&*cmd_place); } argv }; // 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())?; // Call start function. ecx.call_function( start_instance, Abi::Rust, &[Scalar::from_pointer(main_ptr, &ecx).into(), argc.into(), argv], Some(&ret_place.into()), StackPopCleanup::None { cleanup: true }, )?; Ok((ecx, ret_place)) } /// Evaluates the main function specified by `main_id`. /// Returns `Some(return_code)` if program executed completed. /// Returns `None` if an evaluation error occured. pub fn eval_main<'tcx>(tcx: TyCtxt<'tcx>, main_id: DefId, config: MiriConfig) -> Option { // Copy setting before we move `config`. let ignore_leaks = config.ignore_leaks; let (mut ecx, ret_place) = match create_ecx(tcx, main_id, config) { Ok(v) => v, Err(err) => { err.print_backtrace(); panic!("Miri initialization error: {}", err.kind()) } }; // Perform the main execution. let res: InterpResult<'_, i64> = (|| { // Main loop. loop { let info = ecx.preprocess_diagnostics(); match ecx.schedule()? { SchedulingAction::ExecuteStep => { assert!(ecx.step()?, "a terminated thread was scheduled for execution"); } SchedulingAction::ExecuteTimeoutCallback => { assert!( ecx.machine.communicate(), "scheduler callbacks require disabled isolation, but the code \ that created the callback did not check it" ); ecx.run_timeout_callback()?; } SchedulingAction::ExecuteDtors => { // This will either enable the thread again (so we go back // to `ExecuteStep`), or determine that this thread is done // for good. ecx.schedule_next_tls_dtor_for_active_thread()?; } SchedulingAction::Stop => { break; } } ecx.process_diagnostics(info); } let return_code = ecx.read_scalar(&ret_place.into())?.to_machine_isize(&ecx)?; Ok(return_code) })(); // Machine cleanup. EnvVars::cleanup(&mut ecx).unwrap(); // Process the result. match res { Ok(return_code) => { if !ignore_leaks { // Check for thread leaks. if !ecx.have_all_terminated() { tcx.sess.err( "the main thread terminated without waiting for all remaining threads", ); tcx.sess.note_without_error("pass `-Zmiri-ignore-leaks` to disable this check"); return None; } // Check for memory leaks. info!("Additonal static roots: {:?}", ecx.machine.static_roots); let leaks = ecx.memory.leak_report(&ecx.machine.static_roots); if leaks != 0 { tcx.sess.err("the evaluated program leaked memory"); tcx.sess.note_without_error("pass `-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) } Err(e) => report_error(&ecx, e), } }