Struct RegisterUnsharing

pub struct RegisterUnsharing { /* private fields */ }

Unsharing registers reduces the amount of multiplexers used in the final design, trading them off for more memory.

A register use is said to be shared if it is used to store multiple, non-overlapping values in it. Unsharing, then, is the process of identifying such usages of registers and generating new registers to store non-overlapping values. For example, the following program:

let x = 1;
x = x + 2;
x = x + 3

Can be rewritten as:

let x = 1;
let y = x + 2;
let z = y + 3;

On the other hand, the following use of a register cannot be unshared:

let x = 0;
for i in 0..10 {
  x = x + 1;
}

Trait Implementations

impl Default for RegisterUnsharing

fn default() -> RegisterUnsharing

Returns the “default value” for a type.

impl Named for RegisterUnsharing

fn name() -> &'static str

The name of a pass. Is used for identifying passes.

fn description() -> &'static str

A short description of the pass.

fn opts() -> Vec<PassOpt>

Set of options that can be passed to the pass. The options contains a tuple of the option name and a description.

impl Visitor for RegisterUnsharing

fn start( &mut self, comp: &mut Component, sigs: &LibrarySignatures, _comps: &[Component], ) -> VisResult

Executed before the traversal begins.

fn invoke( &mut self, invoke: &mut Invoke, _comp: &mut Component, _sigs: &LibrarySignatures, _comps: &[Component], ) -> VisResult

Executed at an ir::Invoke node.

fn static_invoke( &mut self, invoke: &mut StaticInvoke, _comp: &mut Component, _sigs: &LibrarySignatures, _comps: &[Component], ) -> VisResult

Executed at a ir::StaticInvoke node.

fn precondition(_ctx: &Context) -> Option<String>

where Self: Sized,

Precondition for this pass to run on the program. If this function returns None, the pass triggers. Otherwise it aborts and logs the string as the reason.

fn start_context(&mut self, _ctx: &mut Context) -> VisResult

Transform the ir::Context before visiting the components.

fn finish_context(&mut self, _ctx: &mut Context) -> VisResult

Transform the ir::Context after visiting the components.

fn iteration_order() -> Order

where Self: Sized,

Define the iteration order in which components should be visited

fn traverse_component( &mut self, comp: &mut Component, signatures: &LibrarySignatures, components: &[Component], ) -> CalyxResult<()>

where Self: Sized,

Define the traversal over a component. Calls Visitor::start, visits each control node, and finally calls Visitor::finish.

fn do_pass(&mut self, context: &mut Context) -> CalyxResult<()>

where Self: Sized + ConstructVisitor + Named,

Run the visitor on a given program ir::Context. The function mutably borrows the control program in each component and traverses it.

fn do_pass_default(context: &mut Context) -> CalyxResult<Self>

where Self: ConstructVisitor + Sized + Named,

Build a Default implementation of this pass and call Visitor::do_pass using it.

fn finish( &mut self, _comp: &mut Component, _sigs: &LibrarySignatures, _comps: &[Component], ) -> VisResult

Executed after the traversal ends. This method is always invoked regardless of the Action returned from the children.

fn start_seq( &mut self, _s: &mut Seq, _comp: &mut Component, _sigs: &LibrarySignatures, _comps: &[Component], ) -> VisResult

Executed before visiting the children of a ir::Seq node.

fn finish_seq( &mut self, _s: &mut Seq, _comp: &mut Component, _sigs: &LibrarySignatures, _comps: &[Component], ) -> VisResult

Executed after visiting the children of a ir::Seq node.

fn start_par( &mut self, _s: &mut Par, _comp: &mut Component, _sigs: &LibrarySignatures, _comps: &[Component], ) -> VisResult

Executed before visiting the children of a ir::Par node.

fn finish_par( &mut self, _s: &mut Par, _comp: &mut Component, _sigs: &LibrarySignatures, _comps: &[Component], ) -> VisResult

Executed after visiting the children of a ir::Par node.

fn start_if( &mut self, _s: &mut If, _comp: &mut Component, _sigs: &LibrarySignatures, _comps: &[Component], ) -> VisResult

Executed before visiting the children of a ir::If node.

fn finish_if( &mut self, _s: &mut If, _comp: &mut Component, _sigs: &LibrarySignatures, _comps: &[Component], ) -> VisResult

Executed after visiting the children of a ir::If node.

fn start_while( &mut self, _s: &mut While, _comp: &mut Component, _sigs: &LibrarySignatures, _comps: &[Component], ) -> VisResult

Executed before visiting the children of a ir::While node.

fn finish_while( &mut self, _s: &mut While, _comp: &mut Component, _sigs: &LibrarySignatures, _comps: &[Component], ) -> VisResult

Executed after visiting the children of a ir::While node.

fn start_repeat( &mut self, _s: &mut Repeat, _comp: &mut Component, _sigs: &LibrarySignatures, _comps: &[Component], ) -> VisResult

Executed before visiting the children of a ir::Repeat node.

fn finish_repeat( &mut self, _s: &mut Repeat, _comp: &mut Component, _sigs: &LibrarySignatures, _comps: &[Component], ) -> VisResult

Executed after visiting the children of a ir::Repeat node.

fn start_static_control( &mut self, _s: &mut StaticControl, _comp: &mut Component, _sigs: &LibrarySignatures, _comps: &[Component], ) -> VisResult

Executed before visiting the contents of an ir::StaticControl node.

fn finish_static_control( &mut self, _s: &mut StaticControl, _comp: &mut Component, _sigs: &LibrarySignatures, _comps: &[Component], ) -> VisResult

Executed after visiting the contents of an ir::StaticControl node.

fn enable( &mut self, _s: &mut Enable, _comp: &mut Component, _sigs: &LibrarySignatures, _comps: &[Component], ) -> VisResult

Executed at an ir::Enable node.

fn fsm_enable( &mut self, _s: &mut FSMEnable, _comp: &mut Component, _sigs: &LibrarySignatures, _comps: &[Component], ) -> VisResult

Executed at an ir::FSMEnable node.

fn static_enable( &mut self, _s: &mut StaticEnable, _comp: &mut Component, _sigs: &LibrarySignatures, _comps: &[Component], ) -> VisResult

Executed at an ir::StaticEnable node.

fn start_static_if( &mut self, _s: &mut StaticIf, _comp: &mut Component, _sigs: &LibrarySignatures, _comps: &[Component], ) -> VisResult

Executed before visiting the children of a ir::StaticIf node.

fn finish_static_if( &mut self, _s: &mut StaticIf, _comp: &mut Component, _sigs: &LibrarySignatures, _comps: &[Component], ) -> VisResult

Executed after visiting the children of a ir::StaticIf node.

fn start_static_repeat( &mut self, _s: &mut StaticRepeat, _comp: &mut Component, _sigs: &LibrarySignatures, _comps: &[Component], ) -> VisResult

Executed before visiting the children of a ir::StaticRepeat node.

fn finish_static_repeat( &mut self, _s: &mut StaticRepeat, _comp: &mut Component, _sigs: &LibrarySignatures, _comps: &[Component], ) -> VisResult

Executed after visiting the children of a ir::StaticRepeat node.

fn start_static_seq( &mut self, _s: &mut StaticSeq, _comp: &mut Component, _sigs: &LibrarySignatures, _comps: &[Component], ) -> VisResult

fn finish_static_seq( &mut self, _s: &mut StaticSeq, _comp: &mut Component, _sigs: &LibrarySignatures, _comps: &[Component], ) -> VisResult

fn start_static_par( &mut self, _s: &mut StaticPar, _comp: &mut Component, _sigs: &LibrarySignatures, _comps: &[Component], ) -> VisResult

fn finish_static_par( &mut self, _s: &mut StaticPar, _comp: &mut Component, _sigs: &LibrarySignatures, _comps: &[Component], ) -> VisResult

fn empty( &mut self, _s: &mut Empty, _comp: &mut Component, _sigs: &LibrarySignatures, _comps: &[Component], ) -> VisResult

Executed at an ir::Empty node.