QoalaHost (LIR)¶

The qoalahost dialect describes the classical host body of an LIR program — the part that runs on the CPS. A qoalahost.main_func contains a sequence of blocks, each tagged with qoalahost.blk_meta. Quantum work is delegated to NetQASM routines via qoalahost.call, and remote nodes are referenced through qremote.remote symbols.

Source: include/Dialect/QoalaHost/{QoalaHost,QoalaHostDialect,QoalaHostOps}.td.

All ops in this dialect carry the QuantumOpInterface trait via the dialect's op base class.

Structural ops¶

`qoalahost.main_func`¶

The CPS entry point. Hosts the classical program structure.

Description: function wrapper for the operations that are supposed to run on the host machine (CPS).
Traits: AffineScope, AutomaticAllocationScope, FunctionOpInterface, IsolatedFromAbove, Symbol. Has a region verifier that ensures the body only contains operations from qoalahost, arith, memref, and cf.
Custom assembly format.

`qoalahost.call`¶

Direct call to a netqasm.local_routine or netqasm.request_routine.

Why a Terminator? Per the iQoala block-shape requirements (one call per QL/QR block), qoalahost.call is given the Terminator trait. This forces every call to live in its own block, since each MLIR block can only have one terminator.
Traits: CallOpInterface, MemRefsNormalizable, SymbolUserOpInterface, Terminator, QuantumOpInterface.
Operands: callee (FlatSymbolRefAttr), Variadic<AnyType> arguments.
Results: Variadic<AnyType> (the return values of the routine).
Format: $callee "(" $operands ")" attr-dict ":" functional-type($operands, results).

`qoalahost.return`¶

Function-return terminator for qoalahost.main_func bodies.

Traits: Pure, HasParent<"MainFuncOp">, ReturnLike, Terminator.

Block metadata¶

`qoalahost.blk_meta`¶

A no-op annotation that records per-block metadata used by the runtime and the analyses. Every block in main_func is expected to have one.

Attributes:
block_id: StrAttr
predecessors: StrArrayAttr
dependencies: StrArrayAttr
prev_comm: StrAttr
prev_ent: StrAttr
deadlines: DictionaryAttr
Trait: HasParent<"MainFuncOp">.

qoalahost-add-block-precedences populates predecessors and (with use-online-scheduler=true) the floater-to-branch dependency edges. qoalahost-reorder-blocks reorders blocks and (with with-deadlines=true) computes the deadlines dictionary.

`qoalahost.remote_id_ref`¶

A placeholder operation that records, for a given remote, whether a classical and/or quantum socket should be reserved. Filled in by the LIR-to-iQoala translation.

Attributes: remote: FlatSymbolRefAttr, classical: BoolAttr, quantum: BoolAttr.
Trait: HasParent<"MainFuncOp">.

Nop terminators¶

The dialect provides two nop ops to satisfy MLIR's "every block has a terminator" requirement when the natural block content does not include one.

Op	Trait	Use
`qoalahost.nop`	—	Mid-block placeholder; no terminator effect.
`qoalahost.nop_term`	`Terminator`	Use as the terminator of CL blocks (classical-only blocks that contain no `call`/`recv`).

Classical communication¶

qoalahost mirrors the classical send/recv set from QMem, but all recv_* ops are Terminators, for the same one-recv-per-block reason as qoalahost.call. They also implement ClassicalCommInterface and UsesRemoteInterface.

Op	Operands / attrs	Results	Trait notes
`qoalahost.send_int`	`i32`, `remote`	—	—
`qoalahost.recv_int`	`remote`	`i32`	`Terminator`.
`qoalahost.send_float`	`f32`, `remote`	—	—
`qoalahost.recv_float`	`remote`	`f32`	`Terminator`.
`qoalahost.send_ints`	`tensor<?xi32>`, `remote`	—	—
`qoalahost.recv_ints`	`remote`, `length: i32` (attr)	`tensor<?xi32>`	`Terminator`.
`qoalahost.send_floats`	`tensor<?xf32>`, `remote`	—	—
`qoalahost.recv_floats`	`remote`, `length: i32` (attr)	`tensor<?xf32>`	`Terminator`.

Example¶

module {
  qremote.remote @Bob

  netqasm.local_routine @subrt() -> i1 {
    %v = netqasm.qalloc : i32
    netqasm.init %v
    %m = netqasm.measure %v : i1
    netqasm.return %m : i1
  }

  qoalahost.main_func @main() {
    qoalahost.blk_meta {
      block_id = "block_0", predecessors = [], dependencies = [],
      prev_comm = "", prev_ent = "", deadlines = {}
    }
    qoalahost.remote_id_ref { remote = @Bob, classical = true, quantum = false }
    qoalahost.nop_term

  ^bb1:
    qoalahost.blk_meta {
      block_id = "block_1", predecessors = ["block_0"], dependencies = [],
      prev_comm = "", prev_ent = "", deadlines = {}
    }
    %m = qoalahost.call @subrt() : () -> i1

  ^bb2:
    qoalahost.blk_meta {
      block_id = "block_2", predecessors = ["block_1"], dependencies = [],
      prev_comm = "", prev_ent = "", deadlines = {}
    }
    qoalahost.send_int %m, @Bob : i32
    qoalahost.return
  }
}

(Adapted from test/IR/LIR/lir_local.mlir.)

QoalaHost (LIR)¶

Structural ops¶

qoalahost.main_func¶

qoalahost.call¶

qoalahost.return¶