//! Main evaluator loop and setting up the initial stack frame. use std::ffi::OsStr; use std::convert::TryFrom; use rand::rngs::StdRng; use rand::SeedableRng; use rustc_target::abi::LayoutOf; use rustc_middle::ty::{self, TyCtxt}; use rustc_hir::def_id::DefId; use crate::*; /// 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, /// Determines if communication with the host environment is enabled. pub communicate: bool, /// 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 borrow id to report about pub tracked_pointer_tag: Option, /// The allocation id to report about. pub tracked_alloc_id: Option, } impl Default for MiriConfig { fn default() -> MiriConfig { MiriConfig { validate: true, stacked_borrows: true, communicate: false, ignore_leaks: false, excluded_env_vars: vec![], args: vec![], seed: None, tracked_pointer_tag: None, tracked_alloc_id: None, } } } /// 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<'tcx>>, MPlaceTy<'tcx, Tag>)> { let mut ecx = InterpCx::new( tcx.at(rustc_span::source_map::DUMMY_SP), ty::ParamEnv::reveal_all(), Evaluator::new(config.communicate, config.validate), MemoryExtra::new( StdRng::seed_from_u64(config.seed.unwrap_or(0)), config.stacked_borrows, config.tracked_pointer_tag, config.tracked_alloc_id, ), ); // Complete initialization. EnvVars::init(&mut ecx, config.excluded_env_vars)?; MemoryExtra::init_extern_statics(&mut ecx)?; // 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(); // 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)?; argvs.push(arg_place.ptr); } // 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_scalar(arg, place.into())?; } ecx.memory.mark_immutable(argvs_place.ptr.assert_ptr().alloc_id)?; // A pointer to that place is the 3rd argument for main. let argv = argvs_place.ptr; // Store `argc` and `argv` for macOS `_NSGetArg{c,v}`. { let argc_place = ecx.allocate(ecx.layout_of(tcx.types.isize)?, MiriMemoryKind::Machine.into()); ecx.write_scalar(argc, argc_place.into())?; ecx.machine.argc = Some(argc_place.ptr); let argv_place = ecx.allocate( ecx.layout_of(tcx.mk_imm_ptr(tcx.types.unit))?, MiriMemoryKind::Machine.into(), ); ecx.write_scalar(argv, argv_place.into())?; ecx.machine.argv = Some(argv_place.ptr); } // 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.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.mplace_field(cmd_place, idx)?; ecx.write_scalar(Scalar::from_u16(c), place.into())?; } } argv }; // Return place (in static memory so that it does not count as leak). let ret_place = ecx.allocate(ecx.layout_of(tcx.types.isize)?, MiriMemoryKind::Machine.into()); // Call start function. ecx.call_function( start_instance, &[main_ptr.into(), argc.into(), argv.into()], Some(ret_place.into()), StackPopCleanup::None { cleanup: true }, )?; // Set the last_error to 0 let errno_layout = ecx.layout_of(tcx.types.u32)?; let errno_place = ecx.allocate(errno_layout, MiriMemoryKind::Machine.into()); ecx.write_scalar(Scalar::from_u32(0), errno_place.into())?; ecx.machine.last_error = Some(errno_place); 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 { // FIXME: on Windows, locks and TLS dtor management allocate and leave that memory in `static`s. // So we need https://github.com/rust-lang/miri/issues/940 to fix the leaks there. let ignore_leaks = config.ignore_leaks || tcx.sess.target.target.target_os == "windows"; let (mut ecx, ret_place) = match create_ecx(tcx, main_id, config) { Ok(v) => v, Err(mut err) => { err.print_backtrace(); panic!("Miri initialization error: {}", err.kind) } }; // Perform the main execution. let res: InterpResult<'_, i64> = (|| { // Main loop. while ecx.step()? { ecx.process_diagnostics(); } // Read the return code pointer *before* we run TLS destructors, to assert // that it was written to by the time that `start` lang item returned. let return_code = ecx.read_scalar(ret_place.into())?.not_undef()?.to_machine_isize(&ecx)?; // Global destructors. ecx.run_tls_dtors()?; Ok(return_code) })(); // Machine cleanup. EnvVars::cleanup(&mut ecx).unwrap(); // Process the result. match res { Ok(return_code) => { if !ignore_leaks { let leaks = ecx.memory.leak_report(); if leaks != 0 { tcx.sess.err("the evaluated program leaked memory"); // Ignore the provided return code - let the reported error // determine the return code. return None; } } Some(return_code) } Err(e) => report_error(&ecx, e), } }