Crate miri

source ·



  • clock 🔒
  • eval 🔒
    Main evaluator loop and setting up the initial stack frame.
  • helpers 🔒
  • An interpreter for MIR used in CTFE and by miri
  • intptrcast 🔒
  • machine 🔒
    Global machine state as well as implementation of the interpreter engine Machine trait.
  • This is a “monotonic FxHashMap”: A FxHashMap that, when shared, can be pushed to but not otherwise mutated. We also box items in the map. This means we can safely provide shared references into existing items in the FxHashMap, because they will not be dropped (from being removed) or moved (because they are boxed). The API is completely tailored to what needs. It is still in a separate file to minimize the amount of code that has to care about the unsafety.
  • operator 🔒
  • range_map 🔒
    Implements a map from integer indices to data. Rather than storing data for every index, internally, this maps entire ranges to the data. To this end, the APIs all work on ranges, not on individual integers. Ranges are split as necessary (e.g., when [0,5) is first associated with X, and then [1,2) is mutated). Users must not depend on whether a range is coalesced or not, even though this is observable via the iteration APIs.
  • shims 🔒


  • A lot of the flexibility above is just needed for Miri, but all “compile-time” machines (CTFE and ConstProp) use the same instance. Here, we share that code.


  • Extra per-allocation data
  • The information that makes up a memory access: offset and size.
  • A reference to some allocation that was already bounds-checked for the given region and had the on-access machine hooks run.
  • A reference to some allocation that was already bounds-checked for the given region and had the on-access machine hooks run.
  • This type represents an Allocation in the Miri/CTFE core engine.
  • Details of an access to uninitialized bytes / bad pointer bytes where it is not allowed.
  • Tracking pointer provenance
  • Holds all of the relevant data for when unwinding hits a try frame.
  • A monotone clock used for Instant simulation.
  • 0 is used to indicate that the id was not yet assigned and, therefore, is not a valid identifier.
  • Interned types generally have an Outer type and an Inner type, where Outer is a newtype around Interned<Inner>, and all the operations are done on Outer, because all occurrences are interned. E.g. Ty is an outer type and TyKind is its inner type.
  • The type of provenance in the compile-time interpreter. This is a packed representation of an AllocId and an immutable: bool.
  • Type of dynamic symbols (for dlsym et al)
  • A stack frame.
  • Extra data stored with each stack frame
  • What we store about a frame in an interpreter backtrace.
  • Uniquely identifies one of the following:
  • 0 is used to indicate that the id was not yet assigned and, therefore, is not a valid identifier.
  • Packages the kind of error we got from the const code interpreter up with a Rust-level backtrace of where the error occurred. These should always be constructed by calling .into() on an InterpError. In rustc_mir::interpret, we have throw_err_* macros for this.
  • An item in the per-location borrow stack.
  • Input argument for tcx.lit_to_const.
  • A MemPlace with its layout. Constructing it is only possible in this module.
  • Configuration needed to spawn a Miri instance.
  • The machine itself.
  • Information about a misaligned pointer.
  • 0 is used to indicate that the id was not yet assigned and, therefore, is not a valid identifier.
  • Represents a pointer in the Miri engine.
  • Precomputed layouts of primitive types
  • State for tracking recursive validation of references
  • 0 is used to indicate that the id was not yet assigned and, therefore, is not a valid identifier.
  • Information about a size mismatch.
  • Extra per-location state.
  • Extra per-allocation state.
  • A thread identifier.
  • A set of threads.
  • Tree structure with both parents and children since we want to be able to traverse the tree efficiently in both directions.


  • We have our own error type that does not know about the AllocId; that information is added when converting to InterpError.
  • The return value of get_alloc_info indicates the “kind” of the allocation.
  • Valid atomic fence orderings, subset of atomic::Ordering.
  • Valid atomic read orderings, subset of atomic::Ordering.
  • Valid atomic read-write orderings, alias of atomic::Ordering (not non-exhaustive).
  • Valid atomic write orderings, subset of atomic::Ordering.
  • Which borrow tracking method to use
  • Details of which pointer is not aligned.
  • Details of why a pointer had to be in-bounds.
  • Extra things to check for during validation of CTFE results.
  • An argment passed to a function.
  • The value of a function pointer.
  • An allocation in the global (tcx-managed) memory can be either a function pointer, a static, or a “real” allocation with some data in it.
  • An Immediate represents a single immediate self-contained Rust value.
  • A contiguous chunk of initialized or uninitialized memory.
  • How a constant value should be interned.
  • Error information for when the program we executed turned out not to actually be a valid program. This cannot happen in stand-alone Miri, but it can happen during CTFE/ConstProp where we work on generic code or execution does not have all information available.
  • Error type for tcx.lit_to_const.
  • Information required for the sound usage of a MemPlace.
  • Extra memory kinds
  • Miri specific diagnostics
  • Describes the constraints placed on offset-projections.
  • Indicates which permission is granted (by this item to some pointers)
  • Pointer provenance.
  • The “extra” information a pointer has over a regular AllocId.
  • Error information for when the program exhausted the resources granted to it by the interpreter.
  • Policy on whether to recurse into fields to retag
  • A Scalar represents an immediate, primitive value existing outside of a memory::Allocation. It is in many ways like a small chunk of an Allocation, up to 16 bytes in size. Like a range of bytes in an Allocation, a Scalar can either represent the raw bytes of a simple value or a pointer into another Allocation
  • Data returned by Machine::stack_pop, to provide further control over the popping of the stack frame
  • Details of premature program termination.
  • A specific moment in time.
  • Error information for when the program caused Undefined Behavior.
  • Error information for when the program did something that might (or might not) be correct to do according to the Rust spec, but due to limitations in the interpreter, the operation could not be carried out. These limitations can differ between CTFE and the Miri engine, e.g., CTFE does not support dereferencing pointers at integral addresses.


  • Insert rustc arguments at the beginning of the argument list that Miri wants to be set per default, for maximal validation power. Also disable the MIR pass that inserts an alignment check on every pointer dereference. Miri does that too, and with a better error message.


  • Functionality required for the bytes of an Allocation.
  • The functionality needed by memory to manage its allocations
  • Methods of this trait signifies a point where CTFE evaluation would fail and some use case dependent behaviour can instead be applied.
  • A trait for machine-specific errors (or other “machine stop” conditions).
  • Whether this kind of memory is allowed to leak
  • A little trait that’s useful to be inherited by extension traits.
  • A thing that we can project into, and that has a layout.
  • This trait abstracts over the kind of provenance that is associated with a Pointer. It is mostly opaque; the Machine trait extends it with some more operations that also have access to some global state. The Debug rendering is used to display bare provenance, and for the default impl of fmt.
  • The Readable trait describes interpreter values that one can read from.
  • How to traverse a value and what to do when we are at the leaves.
  • The Weiteable trait describes interpreter values that can be written to.


Type Aliases§