265 lines
11 KiB
Rust
265 lines
11 KiB
Rust
//! Main evaluator loop and setting up the initial stack frame.
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use rand::rngs::StdRng;
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use rand::SeedableRng;
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use rustc::hir::def_id::DefId;
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use rustc::ty::layout::{LayoutOf, Size};
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use rustc::ty::{self, TyCtxt};
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use crate::*;
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/// Configuration needed to spawn a Miri instance.
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#[derive(Clone)]
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pub struct MiriConfig {
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/// Determine if validity checking and Stacked Borrows are enabled.
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pub validate: bool,
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/// Determines if communication with the host environment is enabled.
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pub communicate: bool,
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/// Environment variables that should always be isolated from the host.
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pub excluded_env_vars: Vec<String>,
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/// Command-line arguments passed to the interpreted program.
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pub args: Vec<String>,
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/// The seed to use when non-determinism or randomness are required (e.g. ptr-to-int cast, `getrandom()`).
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pub seed: Option<u64>,
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}
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/// Details of premature program termination.
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pub enum TerminationInfo {
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Exit(i64),
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Abort,
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}
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/// Returns a freshly created `InterpCx`, along with an `MPlaceTy` representing
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/// the location where the return value of the `start` lang item will be
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/// written to.
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/// Public because this is also used by `priroda`.
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pub fn create_ecx<'mir, 'tcx: 'mir>(
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tcx: TyCtxt<'tcx>,
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main_id: DefId,
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config: MiriConfig,
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) -> InterpResult<'tcx, (InterpCx<'mir, 'tcx, Evaluator<'tcx>>, MPlaceTy<'tcx, Tag>)> {
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let mut ecx = InterpCx::new(
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tcx.at(syntax::source_map::DUMMY_SP),
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ty::ParamEnv::reveal_all(),
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Evaluator::new(config.communicate),
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MemoryExtra::new(StdRng::seed_from_u64(config.seed.unwrap_or(0)), config.validate),
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);
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// Complete initialization.
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EnvVars::init(&mut ecx, config.excluded_env_vars);
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// Setup first stack-frame
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let main_instance = ty::Instance::mono(tcx, main_id);
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let main_mir = ecx.load_mir(main_instance.def, None)?;
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if !main_mir.return_ty().is_unit() || main_mir.arg_count != 0 {
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throw_unsup_format!("miri does not support main functions without `fn()` type signatures");
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}
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let start_id = tcx.lang_items().start_fn().unwrap();
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let main_ret_ty = tcx.fn_sig(main_id).output();
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let main_ret_ty = main_ret_ty.no_bound_vars().unwrap();
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let start_instance = ty::Instance::resolve(
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tcx,
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ty::ParamEnv::reveal_all(),
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start_id,
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tcx.mk_substs(::std::iter::once(ty::subst::GenericArg::from(main_ret_ty))),
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)
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.unwrap();
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// First argument: pointer to `main()`.
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let main_ptr = ecx
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.memory
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.create_fn_alloc(FnVal::Instance(main_instance));
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// Second argument (argc): length of `config.args`.
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let argc = Scalar::from_uint(config.args.len() as u128, ecx.pointer_size());
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// Third argument (`argv`): created from `config.args`.
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let argv = {
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// For Windows, construct a command string with all the aguments (before we take apart `config.args`).
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let mut cmd = String::new();
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for arg in config.args.iter() {
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if !cmd.is_empty() {
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cmd.push(' ');
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}
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cmd.push_str(&*shell_escape::windows::escape(arg.as_str().into()));
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}
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// Don't forget `0` terminator.
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cmd.push(std::char::from_u32(0).unwrap());
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// Collect the pointers to the individual strings.
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let mut argvs = Vec::<Pointer<Tag>>::new();
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for arg in config.args {
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// Add `0` terminator.
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let mut arg = arg.into_bytes();
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arg.push(0);
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argvs.push(
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ecx.memory
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.allocate_static_bytes(arg.as_slice(), MiriMemoryKind::Static.into()),
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);
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}
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// Make an array with all these pointers, in the Miri memory.
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let argvs_layout = ecx.layout_of(
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tcx.mk_array(tcx.mk_imm_ptr(tcx.types.u8), argvs.len() as u64),
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)?;
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let argvs_place = ecx.allocate(argvs_layout, MiriMemoryKind::Env.into());
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for (idx, arg) in argvs.into_iter().enumerate() {
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let place = ecx.mplace_field(argvs_place, idx as u64)?;
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ecx.write_scalar(Scalar::Ptr(arg), place.into())?;
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}
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ecx.memory
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.mark_immutable(argvs_place.ptr.assert_ptr().alloc_id)?;
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// A pointer to that place is the argument.
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let argv = argvs_place.ptr;
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// Store `argc` and `argv` for macOS `_NSGetArg{c,v}`.
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{
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let argc_place = ecx.allocate(
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ecx.layout_of(tcx.types.isize)?,
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MiriMemoryKind::Env.into(),
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);
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ecx.write_scalar(argc, argc_place.into())?;
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ecx.machine.argc = Some(argc_place.ptr);
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let argv_place = ecx.allocate(
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ecx.layout_of(tcx.mk_imm_ptr(tcx.types.unit))?,
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MiriMemoryKind::Env.into(),
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);
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ecx.write_scalar(argv, argv_place.into())?;
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ecx.machine.argv = Some(argv_place.ptr);
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}
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// Store command line as UTF-16 for Windows `GetCommandLineW`.
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{
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let cmd_utf16: Vec<u16> = cmd.encode_utf16().collect();
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let cmd_type = tcx.mk_array(tcx.types.u16, cmd_utf16.len() as u64);
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let cmd_place = ecx.allocate(ecx.layout_of(cmd_type)?, MiriMemoryKind::Env.into());
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ecx.machine.cmd_line = Some(cmd_place.ptr);
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// Store the UTF-16 string. We just allocated so we know the bounds are fine.
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let char_size = Size::from_bytes(2);
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for (idx, &c) in cmd_utf16.iter().enumerate() {
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let place = ecx.mplace_field(cmd_place, idx as u64)?;
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ecx.write_scalar(Scalar::from_uint(c, char_size), place.into())?;
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}
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}
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argv
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};
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// Return place (in static memory so that it does not count as leak).
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let ret_place = ecx.allocate(
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ecx.layout_of(tcx.types.isize)?,
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MiriMemoryKind::Static.into(),
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);
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// Call start function.
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ecx.call_function(
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start_instance,
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&[main_ptr.into(), argc, argv],
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Some(ret_place.into()),
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StackPopCleanup::None { cleanup: true },
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)?;
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// Set the last_error to 0
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let errno_layout = ecx.layout_of(tcx.types.u32)?;
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let errno_place = ecx.allocate(errno_layout, MiriMemoryKind::Static.into());
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ecx.write_scalar(Scalar::from_u32(0), errno_place.into())?;
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ecx.machine.last_error = Some(errno_place);
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Ok((ecx, ret_place))
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}
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/// Evaluates the main function specified by `main_id`.
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/// Returns `Some(return_code)` if program executed completed.
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/// Returns `None` if an evaluation error occured.
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pub fn eval_main<'tcx>(tcx: TyCtxt<'tcx>, main_id: DefId, config: MiriConfig) -> Option<i64> {
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let (mut ecx, ret_place) = match create_ecx(tcx, main_id, config) {
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Ok(v) => v,
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Err(mut err) => {
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err.print_backtrace();
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panic!("Miri initialziation error: {}", err.kind)
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}
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};
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// Perform the main execution.
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let res: InterpResult<'_, i64> = (|| {
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ecx.run()?;
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// Read the return code pointer *before* we run TLS destructors, to assert
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// that it was written to by the time that `start` lang item returned.
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let return_code = ecx.read_scalar(ret_place.into())?.not_undef()?.to_machine_isize(&ecx)?;
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ecx.run_tls_dtors()?;
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Ok(return_code)
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})();
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// Process the result.
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match res {
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Ok(return_code) => {
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// Disable the leak test on some platforms where we do not
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// correctly implement TLS destructors.
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let target_os = ecx.tcx.tcx.sess.target.target.target_os.to_lowercase();
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let ignore_leaks = target_os == "windows" || target_os == "macos";
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if !ignore_leaks {
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let leaks = ecx.memory.leak_report();
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if leaks != 0 {
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tcx.sess.err("the evaluated program leaked memory");
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// Ignore the provided return code - let the reported error
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// determine the return code.
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return None;
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}
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}
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return Some(return_code)
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}
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Err(mut e) => {
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// Special treatment for some error kinds
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let msg = match e.kind {
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InterpError::MachineStop(ref info) => {
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let info = info.downcast_ref::<TerminationInfo>()
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.expect("invalid MachineStop payload");
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match info {
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TerminationInfo::Exit(code) => return Some(*code),
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TerminationInfo::Abort =>
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format!("the evaluated program aborted execution")
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}
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}
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err_unsup!(NoMirFor(..)) =>
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format!("{}. Did you set `MIRI_SYSROOT` to a Miri-enabled sysroot? You can prepare one with `cargo miri setup`.", e),
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_ => e.to_string()
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};
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e.print_backtrace();
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if let Some(frame) = ecx.stack().last() {
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let block = &frame.body.basic_blocks()[frame.block.unwrap()];
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let span = if frame.stmt < block.statements.len() {
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block.statements[frame.stmt].source_info.span
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} else {
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block.terminator().source_info.span
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};
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let msg = format!("Miri evaluation error: {}", msg);
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let mut err = ecx.tcx.sess.struct_span_err(span, msg.as_str());
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let frames = ecx.generate_stacktrace(None);
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err.span_label(span, msg);
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// We iterate with indices because we need to look at the next frame (the caller).
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for idx in 0..frames.len() {
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let frame_info = &frames[idx];
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let call_site_is_local = frames.get(idx + 1).map_or(false, |caller_info| {
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caller_info.instance.def_id().is_local()
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});
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if call_site_is_local {
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err.span_note(frame_info.call_site, &frame_info.to_string());
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} else {
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err.note(&frame_info.to_string());
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}
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}
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err.emit();
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} else {
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ecx.tcx.sess.err(&msg);
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}
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for (i, frame) in ecx.stack().iter().enumerate() {
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trace!("-------------------");
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trace!("Frame {}", i);
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trace!(" return: {:?}", frame.return_place.map(|p| *p));
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for (i, local) in frame.locals.iter().enumerate() {
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trace!(" local {}: {:?}", i, local.value);
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}
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}
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// Let the reported error determine the return code.
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return None;
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}
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}
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}
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