-
-/// Configuration needed to spawn a Miri instance.
-#[derive(Clone)]
-pub struct MiriConfig {
- pub validate: bool,
- pub args: Vec<String>,
-
- // The seed to use when non-determinism is required (e.g. getrandom())
- pub seed: Option<u64>
-}
-
-// Used by priroda.
-pub fn create_ecx<'mir, 'tcx: 'mir>(
- tcx: TyCtxt<'tcx>,
- main_id: DefId,
- config: MiriConfig,
-) -> InterpResult<'tcx, InterpretCx<'mir, 'tcx, Evaluator<'tcx>>> {
- let mut ecx = InterpretCx::new(
- tcx.at(syntax::source_map::DUMMY_SP),
- ty::ParamEnv::reveal_all(),
- Evaluator::new(config.validate),
- );
-
- // FIXME: InterpretCx::new should take an initial MemoryExtra
- ecx.memory_mut().extra.rng = config.seed.map(StdRng::seed_from_u64);
-
- let main_instance = ty::Instance::mono(ecx.tcx.tcx, main_id);
- let main_mir = ecx.load_mir(main_instance.def)?;
-
- if !main_mir.return_ty().is_unit() || main_mir.arg_count != 0 {
- return err!(Unimplemented(
- "miri does not support main functions without `fn()` type signatures"
- .to_owned(),
- ));
- }
-
- 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(
- ecx.tcx.tcx,
- ty::ParamEnv::reveal_all(),
- start_id,
- ecx.tcx.mk_substs(
- ::std::iter::once(ty::subst::Kind::from(main_ret_ty)))
- ).unwrap();
- let start_mir = ecx.load_mir(start_instance.def)?;
-
- if start_mir.arg_count != 3 {
- return err!(AbiViolation(format!(
- "'start' lang item should have three arguments, but has {}",
- start_mir.arg_count
- )));
- }
-
- // Return value (in static memory so that it does not count as leak).
- let ret = ecx.layout_of(start_mir.return_ty())?;
- let ret_ptr = ecx.allocate(ret, MiriMemoryKind::Static.into());
-
- // Push our stack frame.
- ecx.push_stack_frame(
- start_instance,
- // There is no call site.
- DUMMY_SP,
- start_mir,
- Some(ret_ptr.into()),
- StackPopCleanup::None { cleanup: true },
- )?;
-
- let mut args = ecx.frame().body.args_iter();
-
- // First argument: pointer to `main()`.
- let main_ptr = ecx.memory_mut().create_fn_alloc(main_instance);
- let dest = ecx.eval_place(&mir::Place::Base(mir::PlaceBase::Local(args.next().unwrap())))?;
- ecx.write_scalar(Scalar::Ptr(main_ptr), dest)?;
-
- // Second argument (argc): `1`.
- let dest = ecx.eval_place(&mir::Place::Base(mir::PlaceBase::Local(args.next().unwrap())))?;
- let argc = Scalar::from_uint(config.args.len() as u128, dest.layout.size);
- ecx.write_scalar(argc, dest)?;
- // Store argc for macOS's `_NSGetArgc`.
- {
- let argc_place = ecx.allocate(dest.layout, MiriMemoryKind::Env.into());
- ecx.write_scalar(argc, argc_place.into())?;
- ecx.machine.argc = Some(argc_place.ptr.to_ptr()?);
- }
-
- // FIXME: extract main source file path.
- // Third argument (`argv`): created from `config.args`.
- let dest = ecx.eval_place(&mir::Place::Base(mir::PlaceBase::Local(args.next().unwrap())))?;
- // For Windows, 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());
- // Collect the pointers to the individual strings.
- let mut argvs = Vec::<Pointer<Tag>>::new();
- for arg in config.args {
- // Add `0` terminator.
- let mut arg = arg.into_bytes();
- arg.push(0);
- argvs.push(ecx.memory_mut().allocate_static_bytes(arg.as_slice(), MiriMemoryKind::Static.into()));
- }
- // Make an array with all these pointers, in the Miri memory.
- let argvs_layout = ecx.layout_of(ecx.tcx.mk_array(ecx.tcx.mk_imm_ptr(ecx.tcx.types.u8), argvs.len() as u64))?;
- let argvs_place = ecx.allocate(argvs_layout, MiriMemoryKind::Env.into());
- for (idx, arg) in argvs.into_iter().enumerate() {
- let place = ecx.mplace_field(argvs_place, idx as u64)?;
- ecx.write_scalar(Scalar::Ptr(arg), place.into())?;
- }
- ecx.memory_mut().mark_immutable(argvs_place.to_ptr()?.alloc_id)?;
- // Write a pointer to that place as the argument.
- let argv = argvs_place.ptr;
- ecx.write_scalar(argv, dest)?;
- // Store `argv` for macOS `_NSGetArgv`.
- {
- let argv_place = ecx.allocate(dest.layout, MiriMemoryKind::Env.into());
- ecx.write_scalar(argv, argv_place.into())?;
- ecx.machine.argv = Some(argv_place.ptr.to_ptr()?);
- }
- // Store command line as UTF-16 for Windows `GetCommandLineW`.
- {
- let tcx = &{ecx.tcx.tcx};
- let cmd_utf16: Vec<u16> = cmd.encode_utf16().collect();
- let cmd_ptr = ecx.memory_mut().allocate(
- Size::from_bytes(cmd_utf16.len() as u64 * 2),
- Align::from_bytes(2).unwrap(),
- MiriMemoryKind::Env.into(),
- );
- ecx.machine.cmd_line = Some(cmd_ptr);
- // Store the UTF-16 string.
- let char_size = Size::from_bytes(2);
- let cmd_alloc = ecx.memory_mut().get_mut(cmd_ptr.alloc_id)?;
- let mut cur_ptr = cmd_ptr;
- for &c in cmd_utf16.iter() {
- cmd_alloc.write_scalar(
- tcx,
- cur_ptr,
- Scalar::from_uint(c, char_size).into(),
- char_size,
- )?;
- cur_ptr = cur_ptr.offset(char_size, tcx)?;
- }
- }
-
- assert!(args.next().is_none(), "start lang item has more arguments than expected");
-
- Ok(ecx)
-}
-
-pub fn eval_main<'tcx>(
- tcx: TyCtxt<'tcx>,
- main_id: DefId,
- config: MiriConfig,
-) {
- let mut ecx = match create_ecx(tcx, main_id, config) {
- Ok(ecx) => ecx,
- Err(mut err) => {
- err.print_backtrace();
- panic!("Miri initialziation error: {}", err.kind)
- }
- };
-
- // Perform the main execution.
- let res: InterpResult = (|| {
- ecx.run()?;
- ecx.run_tls_dtors()
- })();
-
- // Process the result.
- match res {
- Ok(()) => {
- let leaks = ecx.memory().leak_report();
- // Disable the leak test on some platforms where we do not
- // correctly implement TLS destructors.
- let target_os = ecx.tcx.tcx.sess.target.target.target_os.to_lowercase();
- let ignore_leaks = target_os == "windows" || target_os == "macos";
- if !ignore_leaks && leaks != 0 {
- tcx.sess.err("the evaluated program leaked memory");
- }
- }
- Err(mut e) => {
- // Special treatment for some error kinds
- let msg = match e.kind {
- InterpError::Exit(code) => std::process::exit(code),
- InterpError::NoMirFor(..) =>
- format!("{}. Did you set `MIRI_SYSROOT` to a Miri-enabled sysroot? You can prepare one with `cargo miri setup`.", e),
- _ => e.to_string()
- };
- e.print_backtrace();
- if let Some(frame) = ecx.stack().last() {
- let block = &frame.body.basic_blocks()[frame.block];
- let span = if frame.stmt < block.statements.len() {
- block.statements[frame.stmt].source_info.span
- } else {
- block.terminator().source_info.span
- };
-
- let msg = format!("Miri evaluation error: {}", msg);
- let mut err = struct_error(ecx.tcx.tcx.at(span), msg.as_str());
- let frames = ecx.generate_stacktrace(None);
- err.span_label(span, msg);
- // We iterate with indices because we need to look at the next frame (the caller).
- for idx in 0..frames.len() {
- let frame_info = &frames[idx];
- let call_site_is_local = frames.get(idx+1).map_or(false,
- |caller_info| caller_info.instance.def_id().is_local());
- if call_site_is_local {
- err.span_note(frame_info.call_site, &frame_info.to_string());
- } else {
- err.note(&frame_info.to_string());
- }
- }
- err.emit();
- } else {
- ecx.tcx.sess.err(&msg);
- }
-
- for (i, frame) in ecx.stack().iter().enumerate() {
- trace!("-------------------");
- trace!("Frame {}", i);
- trace!(" return: {:?}", frame.return_place.map(|p| *p));
- for (i, local) in frame.locals.iter().enumerate() {
- trace!(" local {}: {:?}", i, local.value);
- }
- }
- }
- }
-}
-
-#[derive(Debug, Copy, Clone, PartialEq, Eq)]
-pub enum MiriMemoryKind {
- /// `__rust_alloc` memory.
- Rust,
- /// `malloc` memory.
- C,
- /// Part of env var emulation.
- Env,
- /// Statics.
- Static,
-}
-
-impl Into<MemoryKind<MiriMemoryKind>> for MiriMemoryKind {
- #[inline(always)]
- fn into(self) -> MemoryKind<MiriMemoryKind> {
- MemoryKind::Machine(self)
- }
-}
-
-impl MayLeak for MiriMemoryKind {
- #[inline(always)]
- fn may_leak(self) -> bool {
- use self::MiriMemoryKind::*;
- match self {
- Rust | C => false,
- Env | Static => true,
- }
- }
-}
-
-pub struct Evaluator<'tcx> {
- /// Environment variables set by `setenv`.
- /// Miri does not expose env vars from the host to the emulated program.
- pub(crate) env_vars: HashMap<Vec<u8>, Pointer<Tag>>,
-
- /// Program arguments (`Option` because we can only initialize them after creating the ecx).
- /// These are *pointers* to argc/argv because macOS.
- /// We also need the full command line as one string because of Windows.
- pub(crate) argc: Option<Pointer<Tag>>,
- pub(crate) argv: Option<Pointer<Tag>>,
- pub(crate) cmd_line: Option<Pointer<Tag>>,
-
- /// Last OS error.
- pub(crate) last_error: u32,
-
- /// TLS state.
- pub(crate) tls: TlsData<'tcx>,
-
- /// Whether to enforce the validity invariant.
- pub(crate) validate: bool,
-}
-
-impl<'tcx> Evaluator<'tcx> {
- fn new(validate: bool) -> Self {
- Evaluator {
- env_vars: HashMap::default(),
- argc: None,
- argv: None,
- cmd_line: None,
- last_error: 0,
- tls: TlsData::default(),
- validate,
- }
- }
-}
-
-// FIXME: rustc issue <https://github.com/rust-lang/rust/issues/47131>.
-#[allow(dead_code)]
-type MiriEvalContext<'mir, 'tcx> = InterpretCx<'mir, 'tcx, Evaluator<'tcx>>;
-
-// A little trait that's useful to be inherited by extension traits.
-pub trait MiriEvalContextExt<'mir, 'tcx> {
- fn eval_context_ref(&self) -> &MiriEvalContext<'mir, 'tcx>;
- fn eval_context_mut(&mut self) -> &mut MiriEvalContext<'mir, 'tcx>;
-}
-impl<'mir, 'tcx> MiriEvalContextExt<'mir, 'tcx> for MiriEvalContext<'mir, 'tcx> {
- #[inline(always)]
- fn eval_context_ref(&self) -> &MiriEvalContext<'mir, 'tcx> {
- self
- }
- #[inline(always)]
- fn eval_context_mut(&mut self) -> &mut MiriEvalContext<'mir, 'tcx> {
- self
- }
-}
-
-impl<'mir, 'tcx> Machine<'mir, 'tcx> for Evaluator<'tcx> {
- type MemoryKinds = MiriMemoryKind;
-
- type FrameExtra = stacked_borrows::CallId;
- type MemoryExtra = memory::MemoryExtra;
- type AllocExtra = memory::AllocExtra;
- type PointerTag = Tag;
-
- type MemoryMap = MonoHashMap<AllocId, (MemoryKind<MiriMemoryKind>, Allocation<Tag, Self::AllocExtra>)>;
-
- const STATIC_KIND: Option<MiriMemoryKind> = Some(MiriMemoryKind::Static);
-
- #[inline(always)]
- fn enforce_validity(ecx: &InterpretCx<'mir, 'tcx, Self>) -> bool {
- ecx.machine.validate
- }
-
- /// Returns `Ok()` when the function was handled; fail otherwise.
- #[inline(always)]
- fn find_fn(
- ecx: &mut InterpretCx<'mir, 'tcx, Self>,
- instance: ty::Instance<'tcx>,
- args: &[OpTy<'tcx, Tag>],
- dest: Option<PlaceTy<'tcx, Tag>>,
- ret: Option<mir::BasicBlock>,
- ) -> InterpResult<'tcx, Option<&'mir mir::Body<'tcx>>> {
- ecx.find_fn(instance, args, dest, ret)
- }
-
- #[inline(always)]
- fn call_intrinsic(
- ecx: &mut rustc_mir::interpret::InterpretCx<'mir, 'tcx, Self>,
- instance: ty::Instance<'tcx>,
- args: &[OpTy<'tcx, Tag>],
- dest: PlaceTy<'tcx, Tag>,
- ) -> InterpResult<'tcx> {
- ecx.call_intrinsic(instance, args, dest)
- }
-
- #[inline(always)]
- fn ptr_op(
- ecx: &rustc_mir::interpret::InterpretCx<'mir, 'tcx, Self>,
- bin_op: mir::BinOp,
- left: ImmTy<'tcx, Tag>,
- right: ImmTy<'tcx, Tag>,
- ) -> InterpResult<'tcx, (Scalar<Tag>, bool)> {
- ecx.ptr_op(bin_op, left, right)
- }
-
- fn box_alloc(
- ecx: &mut InterpretCx<'mir, 'tcx, Self>,
- dest: PlaceTy<'tcx, Tag>,
- ) -> InterpResult<'tcx> {
- trace!("box_alloc for {:?}", dest.layout.ty);
- // Call the `exchange_malloc` lang item.
- let malloc = ecx.tcx.lang_items().exchange_malloc_fn().unwrap();
- let malloc = ty::Instance::mono(ecx.tcx.tcx, malloc);
- let malloc_mir = ecx.load_mir(malloc.def)?;
- ecx.push_stack_frame(
- malloc,
- malloc_mir.span,
- malloc_mir,
- Some(dest),
- // Don't do anything when we are done. The `statement()` function will increment
- // the old stack frame's stmt counter to the next statement, which means that when
- // `exchange_malloc` returns, we go on evaluating exactly where we want to be.
- StackPopCleanup::None { cleanup: true },
- )?;
-
- let mut args = ecx.frame().body.args_iter();
- let layout = ecx.layout_of(dest.layout.ty.builtin_deref(false).unwrap().ty)?;
-
- // First argument: `size`.
- // (`0` is allowed here -- this is expected to be handled by the lang item).
- let arg = ecx.eval_place(&mir::Place::Base(mir::PlaceBase::Local(args.next().unwrap())))?;
- let size = layout.size.bytes();
- ecx.write_scalar(Scalar::from_uint(size, arg.layout.size), arg)?;
-
- // Second argument: `align`.
- let arg = ecx.eval_place(&mir::Place::Base(mir::PlaceBase::Local(args.next().unwrap())))?;
- let align = layout.align.abi.bytes();
- ecx.write_scalar(Scalar::from_uint(align, arg.layout.size), arg)?;
-
- // No more arguments.
- assert!(
- args.next().is_none(),
- "`exchange_malloc` lang item has more arguments than expected"
- );
- Ok(())
- }
-
- fn find_foreign_static(
- def_id: DefId,
- tcx: TyCtxtAt<'tcx>,
- ) -> InterpResult<'tcx, Cow<'tcx, Allocation>> {
- let attrs = tcx.get_attrs(def_id);
- let link_name = match attr::first_attr_value_str_by_name(&attrs, sym::link_name) {
- Some(name) => name.as_str(),
- None => tcx.item_name(def_id).as_str(),
- };
-
- let alloc = match link_name.get() {
- "__cxa_thread_atexit_impl" => {
- // This should be all-zero, pointer-sized.
- let size = tcx.data_layout.pointer_size;
- let data = vec![0; size.bytes() as usize];
- Allocation::from_bytes(&data, tcx.data_layout.pointer_align.abi)
- }
- _ => return err!(Unimplemented(
- format!("can't access foreign static: {}", link_name),
- )),
- };
- Ok(Cow::Owned(alloc))
- }
-
- #[inline(always)]
- fn before_terminator(_ecx: &mut InterpretCx<'mir, 'tcx, Self>) -> InterpResult<'tcx>
- {
- // We are not interested in detecting loops.
- Ok(())
- }
-
- fn tag_allocation<'b>(
- id: AllocId,
- alloc: Cow<'b, Allocation>,
- kind: Option<MemoryKind<Self::MemoryKinds>>,
- memory: &Memory<'mir, 'tcx, Self>,
- ) -> (Cow<'b, Allocation<Self::PointerTag, Self::AllocExtra>>, Self::PointerTag) {
- let kind = kind.expect("we set our STATIC_KIND so this cannot be None");
- let alloc = alloc.into_owned();
- let (stacks, base_tag) = Stacks::new_allocation(
- id,
- Size::from_bytes(alloc.bytes.len() as u64),
- Rc::clone(&memory.extra.stacked_borrows),
- kind,
- );
- if kind != MiriMemoryKind::Static.into() {
- assert!(alloc.relocations.is_empty(), "Only statics can come initialized with inner pointers");
- // Now we can rely on the inner pointers being static, too.
- }
- let mut memory_extra = memory.extra.stacked_borrows.borrow_mut();
- let alloc: Allocation<Tag, Self::AllocExtra> = Allocation {
- bytes: alloc.bytes,
- relocations: Relocations::from_presorted(
- alloc.relocations.iter()
- // The allocations in the relocations (pointers stored *inside* this allocation)
- // all get the base pointer tag.
- .map(|&(offset, ((), alloc))| (offset, (memory_extra.static_base_ptr(alloc), alloc)))
- .collect()
- ),
- undef_mask: alloc.undef_mask,
- align: alloc.align,
- mutability: alloc.mutability,
- extra: AllocExtra {
- stacked_borrows: stacks,
- intptrcast: Default::default(),
- },
- };
- (Cow::Owned(alloc), base_tag)
- }
-
- #[inline(always)]
- fn tag_static_base_pointer(
- id: AllocId,
- memory: &Memory<'mir, 'tcx, Self>,
- ) -> Self::PointerTag {
- memory.extra.stacked_borrows.borrow_mut().static_base_ptr(id)
- }
-
- #[inline(always)]
- fn retag(
- ecx: &mut InterpretCx<'mir, 'tcx, Self>,
- kind: mir::RetagKind,
- place: PlaceTy<'tcx, Tag>,
- ) -> InterpResult<'tcx> {
- if !ecx.tcx.sess.opts.debugging_opts.mir_emit_retag || !Self::enforce_validity(ecx) {
- // No tracking, or no retagging. The latter is possible because a dependency of ours
- // might be called with different flags than we are, so there are `Retag`
- // statements but we do not want to execute them.
- // Also, honor the whitelist in `enforce_validity` because otherwise we might retag
- // uninitialized data.
- Ok(())
- } else {
- ecx.retag(kind, place)
- }
- }
-
- #[inline(always)]
- fn stack_push(
- ecx: &mut InterpretCx<'mir, 'tcx, Self>,
- ) -> InterpResult<'tcx, stacked_borrows::CallId> {
- Ok(ecx.memory().extra.stacked_borrows.borrow_mut().new_call())
- }
-
- #[inline(always)]
- fn stack_pop(
- ecx: &mut InterpretCx<'mir, 'tcx, Self>,
- extra: stacked_borrows::CallId,
- ) -> InterpResult<'tcx> {
- Ok(ecx.memory().extra.stacked_borrows.borrow_mut().end_call(extra))
- }
-
- fn int_to_ptr(
- int: u64,
- memory: &Memory<'mir, 'tcx, Self>,
- ) -> InterpResult<'tcx, Pointer<Self::PointerTag>> {
- if int == 0 {
- err!(InvalidNullPointerUsage)
- } else if memory.extra.rng.is_none() {
- err!(ReadBytesAsPointer)
- } else {
- intptrcast::GlobalState::int_to_ptr(int, memory)
- }
- }
-
- fn ptr_to_int(
- ptr: Pointer<Self::PointerTag>,
- memory: &Memory<'mir, 'tcx, Self>,
- ) -> InterpResult<'tcx, u64> {
- if memory.extra.rng.is_none() {
- err!(ReadPointerAsBytes)
- } else {
- intptrcast::GlobalState::ptr_to_int(ptr, memory)
- }
- }
-}