Enum FrameStep 

#[non_exhaustive]
pub enum FrameStep {
    Push(PReg),
    SetFramePointer,
    Alloc {
        bytes: u32,
        probe: u32,
    },
    SaveVec {
        reg: PReg,
        offset: i32,
    },
    RestoreVec {
        reg: PReg,
        offset: i32,
    },
    Free(u32),
    Pop(PReg),
}

One step of a prologue or epilogue, in execution order.

Examples

use backend_lang::mir::{Function, SlotKind};
use backend_lang::target::frame::FrameStep;
use backend_lang::x86_64::{WIN64, RBP};

let mut f = Function::new("f", &WIN64);
let _big = f.stack_slot(SlotKind::Local { size: 10000, align: 8 })?;
let frame = f.frame_layout().unwrap();
assert_eq!(frame.prologue()[0], FrameStep::Push(RBP));
assert_eq!(frame.prologue()[1], FrameStep::SetFramePointer);
// Win64 probes frames of a page or more.
assert!(matches!(frame.prologue()[2], FrameStep::Alloc { probe: 4096, .. }));

Variants (Non-exhaustive)

Non-exhaustive enums could have additional variants added in future. Therefore, when matching against variants of non-exhaustive enums, an extra wildcard arm must be added to account for any future variants.

Push(PReg)

Push a register (push r).

SetFramePointer

Point the frame pointer at the stack pointer (mov rbp, rsp).

Alloc

Lower the stack pointer by bytes. With probe non-zero, one page of probe bytes at a time, touching each.

Fields

bytes: u32

Bytes to allocate.

probe: u32

The probe interval, or 0 for one adjustment.

SaveVec

Store a vector register into the frame at [sp + offset].

Fields

reg: PReg

The register.

offset: i32

Its save slot’s offset from the stack pointer.

RestoreVec

Reload a vector register saved by FrameStep::SaveVec.

Fields

reg: PReg

The register.

offset: i32

Its save slot’s offset from the stack pointer.

Free(u32)

Raise the stack pointer by bytes (add rsp, bytes).

Pop(PReg)

Pop a register (pop r).

Trait Implementations

impl Clone for FrameStep

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Copy for FrameStep

impl Debug for FrameStep

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Eq for FrameStep

impl Hash for FrameStep

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl PartialEq for FrameStep

fn eq(&self, other: &Self) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl StructuralPartialEq for FrameStep