Struct rustc_middle::mir::interpret::allocation::Allocation[][src]

pub struct Allocation<Tag = (), Extra = ()> {
    bytes: Vec<u8>,
    relocations: Relocations<Tag>,
    init_mask: InitMask,
    pub align: Align,
    pub mutability: Mutability,
    pub extra: Extra,
}
Expand description

This type represents an Allocation in the Miri/CTFE core engine.

Its public API is rather low-level, working directly with allocation offsets and a custom error type to account for the lack of an AllocId on this level. The Miri/CTFE core engine memory module provides higher-level access.

Fields

bytes: Vec<u8>

The actual bytes of the allocation. Note that the bytes of a pointer represent the offset of the pointer.

relocations: Relocations<Tag>

Maps from byte addresses to extra data for each pointer. Only the first byte of a pointer is inserted into the map; i.e., every entry in this map applies to pointer_size consecutive bytes starting at the given offset.

init_mask: InitMask

Denotes which part of this allocation is initialized.

align: Align

The alignment of the allocation to detect unaligned reads. (Align guarantees that this is a power of two.)

mutability: Mutability

true if the allocation is mutable. Also used by codegen to determine if a static should be put into mutable memory, which happens for static mut and static with interior mutability.

extra: Extra

Extra state for the machine.

Implementations

Creates an allocation initialized by the given bytes

Add Tag and Extra fields

Raw accessors. Provide access to otherwise private bytes.

Looks at a slice which may describe uninitialized bytes or describe a relocation. This differs from get_bytes_with_uninit_and_ptr in that it does no relocation checks (even on the edges) at all. This must not be used for reads affecting the interpreter execution.

Returns the mask indicating which bytes are initialized.

Returns the relocation list.

Byte accessors.

The last argument controls whether we error out when there are uninitialized or pointer bytes. You should never call this, call get_bytes or get_bytes_with_uninit_and_ptr instead,

This function also guarantees that the resulting pointer will remain stable even when new allocations are pushed to the HashMap. copy_repeatedly relies on that.

It is the caller’s responsibility to check bounds and alignment beforehand.

Checks that these bytes are initialized and not pointer bytes, and then return them as a slice.

It is the caller’s responsibility to check bounds and alignment beforehand. Most likely, you want to use the PlaceTy and OperandTy-based methods on InterpCx instead.

It is the caller’s responsibility to handle uninitialized and pointer bytes. However, this still checks that there are no relocations on the edges.

It is the caller’s responsibility to check bounds and alignment beforehand.

Just calling this already marks everything as defined and removes relocations, so be sure to actually put data there!

It is the caller’s responsibility to check bounds and alignment beforehand. Most likely, you want to use the PlaceTy and OperandTy-based methods on InterpCx instead.

A raw pointer variant of get_bytes_mut that avoids invalidating existing aliases into this memory.

Reading and writing.

Validates that ptr.offset and ptr.offset + size do not point to the middle of a relocation. If allow_uninit_and_ptr is false, also enforces that the memory in the given range contains neither relocations nor uninitialized bytes.

Reads a non-ZST scalar.

ZSTs can’t be read because in order to obtain a Pointer, we need to check for ZSTness anyway due to integer pointers being valid for ZSTs.

It is the caller’s responsibility to check bounds and alignment beforehand. Most likely, you want to call InterpCx::read_scalar instead of this method.

Writes a non-ZST scalar.

ZSTs can’t be read because in order to obtain a Pointer, we need to check for ZSTness anyway due to integer pointers being valid for ZSTs.

It is the caller’s responsibility to check bounds and alignment beforehand. Most likely, you want to call InterpCx::write_scalar instead of this method.

Relocations.

Returns all relocations overlapping with the given pointer-offset pair.

Checks that there are no relocations overlapping with the given range.

Removes all relocations inside the given range. If there are relocations overlapping with the edges, they are removed as well and the bytes they cover are marked as uninitialized. This is a somewhat odd “spooky action at a distance”, but it allows strictly more code to run than if we would just error immediately in that case.

Errors if there are relocations overlapping with the edges of the given memory range.

Uninitialized bytes.

Checks whether the given range is entirely initialized.

Returns Ok(()) if it’s initialized. Otherwise returns the range of byte indexes of the first contiguous uninitialized access.

Checks that a range of bytes is initialized. If not, returns the InvalidUninitBytes error which will report the first range of bytes which is uninitialized.

Transferring the initialization mask to other allocations.

Creates a run-length encoding of the initialization mask.

Applies multiple instances of the run-length encoding to the initialization mask.

Applies a relocation copy. The affected range, as defined in the parameters to prepare_relocation_copy is expected to be clear of relocations.

Trait Implementations

Immutably borrows from an owned value. Read more

Returns a copy of the value. Read more

Performs copy-assignment from source. Read more

Formats the value using the given formatter. Read more

Feeds this value into the given Hasher. Read more

Feeds a slice of this type into the given Hasher. Read more

This method returns an Ordering between self and other. Read more

Compares and returns the maximum of two values. Read more

Compares and returns the minimum of two values. Read more

Restrict a value to a certain interval. Read more

This method tests for self and other values to be equal, and is used by ==. Read more

This method tests for !=.

This method returns an ordering between self and other values if one exists. Read more

This method tests less than (for self and other) and is used by the < operator. Read more

This method tests less than or equal to (for self and other) and is used by the <= operator. Read more

This method tests greater than (for self and other) and is used by the > operator. Read more

This method tests greater than or equal to (for self and other) and is used by the >= operator. Read more

Auto Trait Implementations

Blanket Implementations

Gets the TypeId of self. Read more

Immutably borrows from an owned value. Read more

Mutably borrows from an owned value. Read more

Performs the conversion.

Performs the conversion.

The resulting type after obtaining ownership.

Creates owned data from borrowed data, usually by cloning. Read more

🔬 This is a nightly-only experimental API. (toowned_clone_into)

recently added

Uses borrowed data to replace owned data, usually by cloning. Read more

The type returned in the event of a conversion error.

Performs the conversion.

The type returned in the event of a conversion error.

Performs the conversion.

Layout

Note: Unable to compute type layout, possibly due to this type having generic parameters. Layout can only be computed for concrete, fully-instantiated types.