494 lines
17 KiB
Rust
494 lines
17 KiB
Rust
//! Global machine state as well as implementation of the interpreter engine
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//! `Machine` trait.
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use std::borrow::Cow;
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use std::cell::RefCell;
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use std::num::NonZeroU64;
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use std::rc::Rc;
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use rand::rngs::StdRng;
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use rustc_data_structures::fx::FxHashMap;
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use rustc::mir;
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use rustc::ty::{
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self,
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layout::{LayoutOf, Size},
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Ty,
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};
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use rustc_ast::attr;
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use rustc_span::{source_map::Span, symbol::{sym, Symbol}};
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use crate::*;
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// Some global facts about the emulated machine.
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pub const PAGE_SIZE: u64 = 4 * 1024; // FIXME: adjust to target architecture
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pub const STACK_ADDR: u64 = 32 * PAGE_SIZE; // not really about the "stack", but where we start assigning integer addresses to allocations
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pub const STACK_SIZE: u64 = 16 * PAGE_SIZE; // whatever
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pub const NUM_CPUS: u64 = 1;
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/// Extra data stored with each stack frame
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#[derive(Debug)]
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pub struct FrameData<'tcx> {
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/// Extra data for Stacked Borrows.
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pub call_id: stacked_borrows::CallId,
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/// If this is Some(), then this is a special "catch unwind" frame (the frame of the closure
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/// called by `__rustc_maybe_catch_panic`). When this frame is popped during unwinding a panic,
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/// we stop unwinding, use the `CatchUnwindData` to
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/// store the panic payload, and continue execution in the parent frame.
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pub catch_panic: Option<CatchUnwindData<'tcx>>,
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}
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/// Extra memory kinds
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#[derive(Debug, Copy, Clone, PartialEq, Eq)]
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pub enum MiriMemoryKind {
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/// `__rust_alloc` memory.
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Rust,
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/// `malloc` memory.
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C,
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/// Windows `HeapAlloc` memory.
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WinHeap,
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/// Memory for env vars and args, errno, extern statics and other parts of the machine-managed environment.
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Machine,
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/// Rust statics.
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Static,
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}
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impl Into<MemoryKind<MiriMemoryKind>> for MiriMemoryKind {
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#[inline(always)]
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fn into(self) -> MemoryKind<MiriMemoryKind> {
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MemoryKind::Machine(self)
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}
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}
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/// Extra per-allocation data
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#[derive(Debug, Clone)]
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pub struct AllocExtra {
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/// Stacked Borrows state is only added if it is enabled.
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pub stacked_borrows: Option<stacked_borrows::AllocExtra>,
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}
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/// Extra global memory data
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#[derive(Clone, Debug)]
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pub struct MemoryExtra<'tcx> {
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pub stacked_borrows: Option<stacked_borrows::MemoryExtra>,
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pub intptrcast: intptrcast::MemoryExtra,
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/// Mapping extern static names to their canonical allocation.
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extern_statics: FxHashMap<Symbol, AllocId>,
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/// The random number generator used for resolving non-determinism.
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/// Needs to be queried by ptr_to_int, hence needs interior mutability.
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pub(crate) rng: RefCell<StdRng>,
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/// An allocation ID to report when it is being allocated
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/// (helps for debugging memory leaks).
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tracked_alloc_id: Option<AllocId>,
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/// Place where the `environ` static is stored. Lazily initialized, but then never changes.
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pub(crate) environ: Option<MPlaceTy<'tcx, Tag>>,
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}
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impl<'tcx> MemoryExtra<'tcx> {
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pub fn new(rng: StdRng, stacked_borrows: bool, tracked_pointer_tag: Option<PtrId>, tracked_alloc_id: Option<AllocId>) -> Self {
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let stacked_borrows = if stacked_borrows {
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Some(Rc::new(RefCell::new(stacked_borrows::GlobalState::new(tracked_pointer_tag))))
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} else {
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None
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};
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MemoryExtra {
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stacked_borrows,
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intptrcast: Default::default(),
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extern_statics: FxHashMap::default(),
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rng: RefCell::new(rng),
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tracked_alloc_id,
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environ: None,
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}
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}
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/// Sets up the "extern statics" for this machine.
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pub fn init_extern_statics<'mir>(
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this: &mut MiriEvalContext<'mir, 'tcx>,
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) -> InterpResult<'tcx> {
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let target_os = this.tcx.sess.target.target.target_os.as_str();
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match target_os {
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"linux" | "macos" => {
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if target_os == "linux" {
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// "__cxa_thread_atexit_impl"
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// This should be all-zero, pointer-sized.
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let layout = this.layout_of(this.tcx.types.usize)?;
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let place = this.allocate(layout, MiriMemoryKind::Machine.into());
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this.write_scalar(Scalar::from_machine_usize(0, &*this.tcx), place.into())?;
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this.memory
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.extra
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.extern_statics
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.insert(Symbol::intern("__cxa_thread_atexit_impl"), place.ptr.assert_ptr().alloc_id)
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.unwrap_none();
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}
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// "environ"
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let layout = this.layout_of(this.tcx.types.usize)?;
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let place = this.allocate(layout, MiriMemoryKind::Machine.into());
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this.write_scalar(Scalar::from_machine_usize(0, &*this.tcx), place.into())?;
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this.memory
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.extra
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.extern_statics
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.insert(Symbol::intern("environ"), place.ptr.assert_ptr().alloc_id)
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.unwrap_none();
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this.memory.extra.environ = Some(place);
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}
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_ => {} // No "extern statics" supported on this platform
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}
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Ok(())
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}
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}
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/// The machine itself.
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pub struct Evaluator<'tcx> {
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/// Environment variables set by `setenv`.
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/// Miri does not expose env vars from the host to the emulated program.
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pub(crate) env_vars: EnvVars,
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/// Program arguments (`Option` because we can only initialize them after creating the ecx).
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/// These are *pointers* to argc/argv because macOS.
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/// We also need the full command line as one string because of Windows.
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pub(crate) argc: Option<Scalar<Tag>>,
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pub(crate) argv: Option<Scalar<Tag>>,
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pub(crate) cmd_line: Option<Scalar<Tag>>,
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/// Last OS error location in memory. It is a 32-bit integer.
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pub(crate) last_error: Option<MPlaceTy<'tcx, Tag>>,
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/// TLS state.
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pub(crate) tls: TlsData<'tcx>,
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/// If enabled, the `env_vars` field is populated with the host env vars during initialization
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/// and random number generation is delegated to the host.
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pub(crate) communicate: bool,
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/// Whether to enforce the validity invariant.
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pub(crate) validate: bool,
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pub(crate) file_handler: FileHandler,
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pub(crate) dir_handler: DirHandler,
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/// The temporary used for storing the argument of
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/// the call to `miri_start_panic` (the panic payload) when unwinding.
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pub(crate) panic_payload: Option<ImmTy<'tcx, Tag>>,
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}
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impl<'tcx> Evaluator<'tcx> {
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pub(crate) fn new(communicate: bool, validate: bool) -> Self {
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Evaluator {
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// `env_vars` could be initialized properly here if `Memory` were available before
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// calling this method.
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env_vars: EnvVars::default(),
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argc: None,
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argv: None,
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cmd_line: None,
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last_error: None,
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tls: TlsData::default(),
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communicate,
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validate,
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file_handler: Default::default(),
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dir_handler: Default::default(),
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panic_payload: None,
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}
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}
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}
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/// A rustc InterpCx for Miri.
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pub type MiriEvalContext<'mir, 'tcx> = InterpCx<'mir, 'tcx, Evaluator<'tcx>>;
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/// A little trait that's useful to be inherited by extension traits.
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pub trait MiriEvalContextExt<'mir, 'tcx> {
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fn eval_context_ref<'a>(&'a self) -> &'a MiriEvalContext<'mir, 'tcx>;
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fn eval_context_mut<'a>(&'a mut self) -> &'a mut MiriEvalContext<'mir, 'tcx>;
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}
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impl<'mir, 'tcx> MiriEvalContextExt<'mir, 'tcx> for MiriEvalContext<'mir, 'tcx> {
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#[inline(always)]
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fn eval_context_ref(&self) -> &MiriEvalContext<'mir, 'tcx> {
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self
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}
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#[inline(always)]
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fn eval_context_mut(&mut self) -> &mut MiriEvalContext<'mir, 'tcx> {
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self
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}
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}
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/// Machine hook implementations.
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impl<'mir, 'tcx> Machine<'mir, 'tcx> for Evaluator<'tcx> {
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type MemoryKinds = MiriMemoryKind;
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type FrameExtra = FrameData<'tcx>;
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type MemoryExtra = MemoryExtra<'tcx>;
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type AllocExtra = AllocExtra;
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type PointerTag = Tag;
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type ExtraFnVal = Dlsym;
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type MemoryMap =
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MonoHashMap<AllocId, (MemoryKind<MiriMemoryKind>, Allocation<Tag, Self::AllocExtra>)>;
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const STATIC_KIND: Option<MiriMemoryKind> = Some(MiriMemoryKind::Static);
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const CHECK_ALIGN: bool = true;
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#[inline(always)]
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fn enforce_validity(ecx: &InterpCx<'mir, 'tcx, Self>) -> bool {
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ecx.machine.validate
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}
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#[inline(always)]
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fn find_mir_or_eval_fn(
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ecx: &mut InterpCx<'mir, 'tcx, Self>,
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_span: Span,
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instance: ty::Instance<'tcx>,
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args: &[OpTy<'tcx, Tag>],
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ret: Option<(PlaceTy<'tcx, Tag>, mir::BasicBlock)>,
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unwind: Option<mir::BasicBlock>,
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) -> InterpResult<'tcx, Option<&'mir mir::Body<'tcx>>> {
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ecx.find_mir_or_eval_fn(instance, args, ret, unwind)
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}
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#[inline(always)]
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fn call_extra_fn(
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ecx: &mut InterpCx<'mir, 'tcx, Self>,
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fn_val: Dlsym,
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args: &[OpTy<'tcx, Tag>],
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ret: Option<(PlaceTy<'tcx, Tag>, mir::BasicBlock)>,
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_unwind: Option<mir::BasicBlock>,
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) -> InterpResult<'tcx> {
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ecx.call_dlsym(fn_val, args, ret)
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}
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#[inline(always)]
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fn call_intrinsic(
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ecx: &mut rustc_mir::interpret::InterpCx<'mir, 'tcx, Self>,
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span: Span,
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instance: ty::Instance<'tcx>,
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args: &[OpTy<'tcx, Tag>],
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ret: Option<(PlaceTy<'tcx, Tag>, mir::BasicBlock)>,
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unwind: Option<mir::BasicBlock>,
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) -> InterpResult<'tcx> {
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ecx.call_intrinsic(span, instance, args, ret, unwind)
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}
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#[inline(always)]
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fn assert_panic(
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ecx: &mut InterpCx<'mir, 'tcx, Self>,
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span: Span,
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msg: &mir::AssertMessage<'tcx>,
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unwind: Option<mir::BasicBlock>,
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) -> InterpResult<'tcx> {
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ecx.assert_panic(span, msg, unwind)
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}
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#[inline(always)]
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fn binary_ptr_op(
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ecx: &rustc_mir::interpret::InterpCx<'mir, 'tcx, Self>,
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bin_op: mir::BinOp,
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left: ImmTy<'tcx, Tag>,
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right: ImmTy<'tcx, Tag>,
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) -> InterpResult<'tcx, (Scalar<Tag>, bool, Ty<'tcx>)> {
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ecx.binary_ptr_op(bin_op, left, right)
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}
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fn box_alloc(
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ecx: &mut InterpCx<'mir, 'tcx, Self>,
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dest: PlaceTy<'tcx, Tag>,
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) -> InterpResult<'tcx> {
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trace!("box_alloc for {:?}", dest.layout.ty);
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let layout = ecx.layout_of(dest.layout.ty.builtin_deref(false).unwrap().ty)?;
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// First argument: `size`.
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// (`0` is allowed here -- this is expected to be handled by the lang item).
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let size = Scalar::from_uint(layout.size.bytes(), ecx.pointer_size());
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// Second argument: `align`.
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let align = Scalar::from_uint(layout.align.abi.bytes(), ecx.pointer_size());
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// Call the `exchange_malloc` lang item.
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let malloc = ecx.tcx.lang_items().exchange_malloc_fn().unwrap();
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let malloc = ty::Instance::mono(ecx.tcx.tcx, malloc);
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ecx.call_function(
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malloc,
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&[size.into(), align.into()],
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Some(dest),
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// Don't do anything when we are done. The `statement()` function will increment
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// the old stack frame's stmt counter to the next statement, which means that when
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// `exchange_malloc` returns, we go on evaluating exactly where we want to be.
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StackPopCleanup::None { cleanup: true },
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)?;
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Ok(())
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}
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fn canonical_alloc_id(mem: &Memory<'mir, 'tcx, Self>, id: AllocId) -> AllocId {
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let tcx = mem.tcx;
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// Figure out if this is an extern static, and if yes, which one.
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let def_id = match tcx.alloc_map.lock().get(id) {
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Some(GlobalAlloc::Static(def_id)) if tcx.is_foreign_item(def_id) => def_id,
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_ => {
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// No need to canonicalize anything.
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return id;
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}
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};
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let attrs = tcx.get_attrs(def_id);
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let link_name = match attr::first_attr_value_str_by_name(&attrs, sym::link_name) {
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Some(name) => name,
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None => tcx.item_name(def_id),
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};
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// Check if we know this one.
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if let Some(canonical_id) = mem.extra.extern_statics.get(&link_name) {
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trace!("canonical_alloc_id: {:?} ({}) -> {:?}", id, link_name, canonical_id);
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*canonical_id
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} else {
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// Return original id; `Memory::get_static_alloc` will throw an error.
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id
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}
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}
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fn init_allocation_extra<'b>(
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memory_extra: &MemoryExtra<'tcx>,
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id: AllocId,
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alloc: Cow<'b, Allocation>,
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kind: Option<MemoryKind<Self::MemoryKinds>>,
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) -> (Cow<'b, Allocation<Self::PointerTag, Self::AllocExtra>>, Self::PointerTag) {
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if Some(id) == memory_extra.tracked_alloc_id {
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register_diagnostic(NonHaltingDiagnostic::CreatedAlloc(id));
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}
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let kind = kind.expect("we set our STATIC_KIND so this cannot be None");
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let alloc = alloc.into_owned();
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let (stacks, base_tag) =
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if let Some(stacked_borrows) = memory_extra.stacked_borrows.as_ref() {
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let (stacks, base_tag) =
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Stacks::new_allocation(id, alloc.size, Rc::clone(stacked_borrows), kind);
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(Some(stacks), base_tag)
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} else {
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// No stacks, no tag.
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(None, Tag::Untagged)
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};
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let mut stacked_borrows = memory_extra.stacked_borrows.as_ref().map(|sb| sb.borrow_mut());
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let alloc: Allocation<Tag, Self::AllocExtra> = alloc.with_tags_and_extra(
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|alloc| {
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if let Some(stacked_borrows) = stacked_borrows.as_mut() {
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// Only statics may already contain pointers at this point
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assert_eq!(kind, MiriMemoryKind::Static.into());
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stacked_borrows.static_base_ptr(alloc)
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} else {
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Tag::Untagged
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}
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},
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AllocExtra { stacked_borrows: stacks },
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);
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(Cow::Owned(alloc), base_tag)
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}
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#[inline(always)]
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fn tag_static_base_pointer(memory_extra: &MemoryExtra<'tcx>, id: AllocId) -> Self::PointerTag {
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if let Some(stacked_borrows) = memory_extra.stacked_borrows.as_ref() {
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stacked_borrows.borrow_mut().static_base_ptr(id)
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} else {
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Tag::Untagged
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}
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}
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#[inline(always)]
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fn retag(
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ecx: &mut InterpCx<'mir, 'tcx, Self>,
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kind: mir::RetagKind,
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place: PlaceTy<'tcx, Tag>,
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) -> InterpResult<'tcx> {
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if ecx.memory.extra.stacked_borrows.is_none() {
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// No tracking.
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Ok(())
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} else {
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ecx.retag(kind, place)
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}
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}
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#[inline(always)]
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fn stack_push(ecx: &mut InterpCx<'mir, 'tcx, Self>) -> InterpResult<'tcx, FrameData<'tcx>> {
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let stacked_borrows = ecx.memory.extra.stacked_borrows.as_ref();
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let call_id = stacked_borrows.map_or(NonZeroU64::new(1).unwrap(), |stacked_borrows| {
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stacked_borrows.borrow_mut().new_call()
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});
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Ok(FrameData { call_id, catch_panic: None })
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}
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#[inline(always)]
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fn stack_pop(
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ecx: &mut InterpCx<'mir, 'tcx, Self>,
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extra: FrameData<'tcx>,
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unwinding: bool,
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) -> InterpResult<'tcx, StackPopInfo> {
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ecx.handle_stack_pop(extra, unwinding)
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}
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#[inline(always)]
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fn int_to_ptr(
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memory: &Memory<'mir, 'tcx, Self>,
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int: u64,
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) -> InterpResult<'tcx, Pointer<Self::PointerTag>> {
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intptrcast::GlobalState::int_to_ptr(int, memory)
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}
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#[inline(always)]
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fn ptr_to_int(
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memory: &Memory<'mir, 'tcx, Self>,
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ptr: Pointer<Self::PointerTag>,
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) -> InterpResult<'tcx, u64> {
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intptrcast::GlobalState::ptr_to_int(ptr, memory)
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}
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}
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impl AllocationExtra<Tag> for AllocExtra {
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#[inline(always)]
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fn memory_read<'tcx>(
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alloc: &Allocation<Tag, AllocExtra>,
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ptr: Pointer<Tag>,
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size: Size,
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) -> InterpResult<'tcx> {
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if let Some(ref stacked_borrows) = alloc.extra.stacked_borrows {
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stacked_borrows.memory_read(ptr, size)
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} else {
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Ok(())
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}
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}
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#[inline(always)]
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fn memory_written<'tcx>(
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alloc: &mut Allocation<Tag, AllocExtra>,
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ptr: Pointer<Tag>,
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size: Size,
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) -> InterpResult<'tcx> {
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if let Some(ref mut stacked_borrows) = alloc.extra.stacked_borrows {
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stacked_borrows.memory_written(ptr, size)
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} else {
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|
Ok(())
|
|
}
|
|
}
|
|
|
|
#[inline(always)]
|
|
fn memory_deallocated<'tcx>(
|
|
alloc: &mut Allocation<Tag, AllocExtra>,
|
|
ptr: Pointer<Tag>,
|
|
size: Size,
|
|
) -> InterpResult<'tcx> {
|
|
if let Some(ref mut stacked_borrows) = alloc.extra.stacked_borrows {
|
|
stacked_borrows.memory_deallocated(ptr, size)
|
|
} else {
|
|
Ok(())
|
|
}
|
|
}
|
|
}
|
|
|
|
impl MayLeak for MiriMemoryKind {
|
|
#[inline(always)]
|
|
fn may_leak(self) -> bool {
|
|
use self::MiriMemoryKind::*;
|
|
match self {
|
|
Rust | C | WinHeap => false,
|
|
Machine | Static => true,
|
|
}
|
|
}
|
|
}
|