Struct Layout

pub struct Layout { /* private fields */ }

The Layout struct determines the layout of blocks and instructions in a function. It does not contain definitions of instructions or blocks, but depends on Inst and Block entity references being defined elsewhere.

This data structure determines:

• The order of blocks in the function.
• Which block contains a given instruction.
• The order of instructions with a block.

While data dependencies are not recorded, instruction ordering does affect control dependencies, so part of the semantics of the program are determined by the layout.

Implementations

impl Layout

pub fn new() -> Self

Create a new empty Layout.

pub fn clear(&mut self)

Clear the layout.

pub fn block_capacity(&self) -> usize

Returns the capacity of the BlockData map.

impl Layout

pub fn pp_cmp<A, B>(&self, a: A, b: B) -> Ordering

where A: Into<ProgramPoint>, B: Into<ProgramPoint>,

Compare the program points a and b in the same block relative to this program order.

Return Less if a appears in the program before b.

This is declared as a generic such that it can be called with Inst and Block arguments directly. Depending on the implementation, there is a good chance performance will be improved for those cases where the type of either argument is known statically.

impl Layout

Methods for laying out blocks.

An unknown block starts out as not inserted in the block layout. The layout is a linear order of inserted blocks. Once a block has been inserted in the layout, instructions can be added. A block can only be removed from the layout when it is empty.

Since every block must end with a terminator instruction which cannot fall through, the layout of blocks do not affect the semantics of the program.

pub fn is_block_inserted(&self, block: Block) -> bool

Is block currently part of the layout?

pub fn append_block(&mut self, block: Block)

Insert block as the last block in the layout.

pub fn insert_block(&mut self, block: Block, before: Block)

Insert block in the layout before the existing block before.

pub fn insert_block_after(&mut self, block: Block, after: Block)

Insert block in the layout after the existing block after.

pub fn remove_block(&mut self, block: Block)

Remove block from the layout.

pub fn blocks(&self) -> Blocks<'_>

Return an iterator over all blocks in layout order.

pub fn entry_block(&self) -> Option<Block>

Get the function’s entry block. This is simply the first block in the layout order.

pub fn last_block(&self) -> Option<Block>

Get the last block in the layout.

pub fn prev_block(&self, block: Block) -> Option<Block>

Get the block preceding block in the layout order.

pub fn next_block(&self, block: Block) -> Option<Block>

Get the block following block in the layout order.

pub fn set_cold(&mut self, block: Block)

Mark a block as “cold”.

This will try to move it out of the ordinary path of execution when lowered to machine code.

pub fn is_cold(&self, block: Block) -> bool

Is the given block cold?

impl Layout

Methods for arranging instructions.

An instruction starts out as not inserted in the layout. An instruction can be inserted into a block at a given position.

pub fn inst_block(&self, inst: Inst) -> Option<Block>

Get the block containing inst, or None if inst is not inserted in the layout.

pub fn pp_block(&self, pp: ProgramPoint) -> Block

Get the block containing the program point pp. Panic if pp is not in the layout.

pub fn append_inst(&mut self, inst: Inst, block: Block)

Append inst to the end of block.

pub fn first_inst(&self, block: Block) -> Option<Inst>

Fetch a block’s first instruction.

pub fn last_inst(&self, block: Block) -> Option<Inst>

Fetch a block’s last instruction.

pub fn next_inst(&self, inst: Inst) -> Option<Inst>

Fetch the instruction following inst.

pub fn prev_inst(&self, inst: Inst) -> Option<Inst>

Fetch the instruction preceding inst.

pub fn insert_inst(&mut self, inst: Inst, before: Inst)

Insert inst before the instruction before in the same block.

pub fn remove_inst(&mut self, inst: Inst)

Remove inst from the layout.

pub fn block_insts(&self, block: Block) -> Insts<'_>

Iterate over the instructions in block in layout order.

pub fn split_block(&mut self, new_block: Block, before: Inst)

Split the block containing before in two.

Insert new_block after the old block and move before and the following instructions to new_block:

old_block:
    i1
    i2
    i3 << before
    i4

becomes:

old_block:
    i1
    i2
new_block:
    i3 << before
    i4

Trait Implementations

impl Clone for Layout

fn clone(&self) -> Layout

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for Layout

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

Formats the value using the given formatter.

impl Hash for Layout

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<'f> IntoIterator for &'f Layout

Use a layout reference in a for loop.

type Item = Block

The type of the elements being iterated over.

type IntoIter = Blocks<'f>

Which kind of iterator are we turning this into?

fn into_iter(self) -> Blocks<'f>

Creates an iterator from a value.

impl PartialEq for Layout

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

Tests for self and other values to be equal, and is used by ==.

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

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl StructuralPartialEq for Layout