Trait rustc_const_eval::interpret::machine::Machine[−][src]

pub trait Machine<'mir, 'tcx>: Sized {
    type MemoryKind: Debug + Display + MayLeak + Eq + 'static;
    type PointerTag: Provenance + Eq + Hash + 'static;
    type ExtraFnVal: Debug + Copy;
    type FrameExtra;
    type MemoryExtra;
    type AllocExtra: Debug + Clone + 'static;
    type MemoryMap: AllocMap<AllocId, (MemoryKind<Self::MemoryKind>, Allocation<Self::PointerTag, Self::AllocExtra>)> + Default + Clone;

    const GLOBAL_KIND: Option<Self::MemoryKind>;
    const PANIC_ON_ALLOC_FAIL: bool;

Show 31 methods
    fn enforce_alignment(memory_extra: &Self::MemoryExtra) -> bool;

    fn force_int_for_alignment_check(memory_extra: &Self::MemoryExtra) -> bool;

    fn enforce_validity(ecx: &InterpCx<'mir, 'tcx, Self>) -> bool;

    fn find_mir_or_eval_fn(
        ecx: &mut InterpCx<'mir, 'tcx, Self>, 
        instance: Instance<'tcx>, 
        abi: Abi, 
        args: &[OpTy<'tcx, Self::PointerTag>], 
        ret: Option<(&PlaceTy<'tcx, Self::PointerTag>, BasicBlock)>, 
        unwind: StackPopUnwind
    ) -> InterpResult<'tcx, Option<&'mir Body<'tcx>>>;

    fn call_extra_fn(
        ecx: &mut InterpCx<'mir, 'tcx, Self>, 
        fn_val: Self::ExtraFnVal, 
        abi: Abi, 
        args: &[OpTy<'tcx, Self::PointerTag>], 
        ret: Option<(&PlaceTy<'tcx, Self::PointerTag>, BasicBlock)>, 
        unwind: StackPopUnwind
    ) -> InterpResult<'tcx>;

    fn call_intrinsic(
        ecx: &mut InterpCx<'mir, 'tcx, Self>, 
        instance: Instance<'tcx>, 
        args: &[OpTy<'tcx, Self::PointerTag>], 
        ret: Option<(&PlaceTy<'tcx, Self::PointerTag>, BasicBlock)>, 
        unwind: StackPopUnwind
    ) -> InterpResult<'tcx>;

    fn assert_panic(
        ecx: &mut InterpCx<'mir, 'tcx, Self>, 
        msg: &AssertMessage<'tcx>, 
        unwind: Option<BasicBlock>
    ) -> InterpResult<'tcx>;

    fn binary_ptr_op(
        ecx: &InterpCx<'mir, 'tcx, Self>, 
        bin_op: BinOp, 
        left: &ImmTy<'tcx, Self::PointerTag>, 
        right: &ImmTy<'tcx, Self::PointerTag>
    ) -> InterpResult<'tcx, (Scalar<Self::PointerTag>, bool, Ty<'tcx>)>;

    fn box_alloc(
        ecx: &mut InterpCx<'mir, 'tcx, Self>, 
        dest: &PlaceTy<'tcx, Self::PointerTag>
    ) -> InterpResult<'tcx>;

    fn extern_static_base_pointer(
        mem: &Memory<'mir, 'tcx, Self>, 
        def_id: DefId
    ) -> InterpResult<'tcx, Pointer<Self::PointerTag>>;

    fn tag_alloc_base_pointer(
        mem: &Memory<'mir, 'tcx, Self>, 
        ptr: Pointer
    ) -> Pointer<Self::PointerTag>;

    fn ptr_from_addr(
        mem: &Memory<'mir, 'tcx, Self>, 
        addr: u64
    ) -> Pointer<Option<Self::PointerTag>>;

    fn ptr_get_alloc(
        mem: &Memory<'mir, 'tcx, Self>, 
        ptr: Pointer<Self::PointerTag>
    ) -> (AllocId, Size);

    fn init_allocation_extra<'b>(
        mem: &Memory<'mir, 'tcx, Self>, 
        id: AllocId, 
        alloc: Cow<'b, Allocation>, 
        kind: Option<MemoryKind<Self::MemoryKind>>
    ) -> Cow<'b, Allocation<Self::PointerTag, Self::AllocExtra>>;

    fn init_frame_extra(
        ecx: &mut InterpCx<'mir, 'tcx, Self>, 
        frame: Frame<'mir, 'tcx, Self::PointerTag>
    ) -> InterpResult<'tcx, Frame<'mir, 'tcx, Self::PointerTag, Self::FrameExtra>>;

    fn stack<'a>(
        ecx: &'a InterpCx<'mir, 'tcx, Self>
    ) -> &'a [Frame<'mir, 'tcx, Self::PointerTag, Self::FrameExtra>];

    fn stack_mut<'a>(
        ecx: &'a mut InterpCx<'mir, 'tcx, Self>
    ) -> &'a mut Vec<Frame<'mir, 'tcx, Self::PointerTag, Self::FrameExtra>>;

    fn enforce_abi(_ecx: &InterpCx<'mir, 'tcx, Self>) -> bool { ... }

    fn load_mir(
        ecx: &InterpCx<'mir, 'tcx, Self>, 
        instance: InstanceDef<'tcx>
    ) -> InterpResult<'tcx, &'tcx Body<'tcx>> { ... }

    fn abort(
        _ecx: &mut InterpCx<'mir, 'tcx, Self>, 
        _msg: String
    ) -> InterpResult<'tcx, !> { ... }

    fn access_local(
        _ecx: &InterpCx<'mir, 'tcx, Self>, 
        frame: &Frame<'mir, 'tcx, Self::PointerTag, Self::FrameExtra>, 
        local: Local
    ) -> InterpResult<'tcx, Operand<Self::PointerTag>> { ... }

    fn access_local_mut<'a>(
        ecx: &'a mut InterpCx<'mir, 'tcx, Self>, 
        frame: usize, 
        local: Local
    ) -> InterpResult<'tcx, Result<&'a mut LocalValue<Self::PointerTag>, MemPlace<Self::PointerTag>>>
    where
        'tcx: 'mir,
    { ... }

    fn before_terminator(
        _ecx: &mut InterpCx<'mir, 'tcx, Self>
    ) -> InterpResult<'tcx> { ... }

    fn before_access_global(
        _memory_extra: &Self::MemoryExtra, 
        _alloc_id: AllocId, 
        _allocation: &Allocation, 
        _static_def_id: Option<DefId>, 
        _is_write: bool
    ) -> InterpResult<'tcx> { ... }

    fn thread_local_static_base_pointer(
        _ecx: &mut InterpCx<'mir, 'tcx, Self>, 
        def_id: DefId
    ) -> InterpResult<'tcx, Pointer<Self::PointerTag>> { ... }

    fn memory_read(
        _memory_extra: &Self::MemoryExtra, 
        _alloc_extra: &Self::AllocExtra, 
        _tag: Self::PointerTag, 
        _range: AllocRange
    ) -> InterpResult<'tcx> { ... }

    fn memory_written(
        _memory_extra: &mut Self::MemoryExtra, 
        _alloc_extra: &mut Self::AllocExtra, 
        _tag: Self::PointerTag, 
        _range: AllocRange
    ) -> InterpResult<'tcx> { ... }

    fn memory_deallocated(
        _memory_extra: &mut Self::MemoryExtra, 
        _alloc_extra: &mut Self::AllocExtra, 
        _tag: Self::PointerTag, 
        _range: AllocRange
    ) -> InterpResult<'tcx> { ... }

    fn retag(
        _ecx: &mut InterpCx<'mir, 'tcx, Self>, 
        _kind: RetagKind, 
        _place: &PlaceTy<'tcx, Self::PointerTag>
    ) -> InterpResult<'tcx> { ... }

    fn after_stack_push(
        _ecx: &mut InterpCx<'mir, 'tcx, Self>
    ) -> InterpResult<'tcx> { ... }

    fn after_stack_pop(
        _ecx: &mut InterpCx<'mir, 'tcx, Self>, 
        _frame: Frame<'mir, 'tcx, Self::PointerTag, Self::FrameExtra>, 
        _unwinding: bool
    ) -> InterpResult<'tcx, StackPopJump> { ... }

}
Expand description

Methods of this trait signifies a point where CTFE evaluation would fail and some use case dependent behaviour can instead be applied.

Associated Types

Additional memory kinds a machine wishes to distinguish from the builtin ones

Pointers are “tagged” with provenance information; typically the AllocId they belong to.

Machines can define extra (non-instance) things that represent values of function pointers. For example, Miri uses this to return a function pointer from dlsym that can later be called to execute the right thing.

Extra data stored in every call frame.

Extra data stored in memory. A reference to this is available when AllocExtra gets initialized, so you can e.g., have an Rc here if there is global state you need access to in the AllocExtra hooks.

Extra data stored in every allocation.

Memory’s allocation map

Associated Constants

The memory kind to use for copied global memory (held in tcx) – or None if such memory should not be mutated and thus any such attempt will cause a ModifiedStatic error to be raised. Statics are copied under two circumstances: When they are mutated, and when tag_allocation (see below) returns an owned allocation that is added to the memory so that the work is not done twice.

Should the machine panic on allocation failures?

Required methods

Whether memory accesses should be alignment-checked.

Whether, when checking alignment, we should force_int and thus support custom alignment logic based on whatever the integer address happens to be.

Whether to enforce the validity invariant

Entry point to all function calls.

Returns either the mir to use for the call, or None if execution should just proceed (which usually means this hook did all the work that the called function should usually have done). In the latter case, it is this hook’s responsibility to advance the instruction pointer! (This is to support functions like __rust_maybe_catch_panic that neither find a MIR nor just jump to ret, but instead push their own stack frame.) Passing destand ret in the same Option proved very annoying when only one of them was used.

Execute fn_val. It is the hook’s responsibility to advance the instruction pointer as appropriate.

Directly process an intrinsic without pushing a stack frame. It is the hook’s responsibility to advance the instruction pointer as appropriate.

Called to evaluate Assert MIR terminators that trigger a panic.

Called for all binary operations where the LHS has pointer type.

Returns a (value, overflowed) pair if the operation succeeded

Heap allocations via the box keyword.

Return the root pointer for the given extern static.

Return a “base” pointer for the given allocation: the one that is used for direct accesses to this static/const/fn allocation, or the one returned from the heap allocator.

Not called on extern or thread-local statics (those use the methods above).

“Int-to-pointer cast”

Convert a pointer with provenance into an allocation-offset pair.

Called to initialize the “extra” state of an allocation and make the pointers it contains (in relocations) tagged. The way we construct allocations is to always first construct it without extra and then add the extra. This keeps uniform code paths for handling both allocations created by CTFE for globals, and allocations created by Miri during evaluation.

kind is the kind of the allocation being tagged; it can be None when it’s a global and GLOBAL_KIND is None.

This should avoid copying if no work has to be done! If this returns an owned allocation (because a copy had to be done to add tags or metadata), machine memory will cache the result. (This relies on AllocMap::get_or being able to add the owned allocation to the map even when the map is shared.)

Called immediately before a new stack frame gets pushed.

Borrow the current thread’s stack.

Mutably borrow the current thread’s stack.

Provided methods

Whether function calls should be ABI-checked.

Entry point for obtaining the MIR of anything that should get evaluated. So not just functions and shims, but also const/static initializers, anonymous constants, …

Called to evaluate Abort MIR terminator.

Called to read the specified local from the frame. Since reading a ZST is not actually accessing memory or locals, this is never invoked for ZST reads.

Called to write the specified local from the frame. Since writing a ZST is not actually accessing memory or locals, this is never invoked for ZST reads.

Called before a basic block terminator is executed. You can use this to detect endlessly running programs.

Called before a global allocation is accessed. def_id is Some if this is the “lazy” allocation of a static.

Return the AllocId for the given thread-local static in the current thread.

Hook for performing extra checks on a memory read access.

Takes read-only access to the allocation so we can keep all the memory read operations take &self. Use a RefCell in AllocExtra if you need to mutate.

Hook for performing extra checks on a memory write access.

Hook for performing extra operations on a memory deallocation.

Executes a retagging operation.

Called immediately after a stack frame got pushed and its locals got initialized.

Called immediately after a stack frame got popped, but before jumping back to the caller.

Implementors