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Merged
merged 1 commit into from
Jun 21, 2022
Merged

Remove unused regsiters, opodes #506

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120 changes: 6 additions & 114 deletions Sources/_StringProcessing/Engine/Instruction.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -27,25 +27,6 @@ extension Instruction {

// MARK: - General Purpose

/// Do nothing
///
/// nop(comment: String?)
///
/// Operand: Optional string register containing a comment or reason
///
case nop

/// Decrement the value stored in a register.
/// Returns whether the value was set to zero
///
/// decrement(_ i: IntReg) -> Bool
///
/// Operands:
/// - Int register to decrease
/// - Condition register set if now zero
///
case decrement

/// Move an immediate value into a register
///
/// moveImmediate(_ i: Int, into: IntReg)
Expand All @@ -65,15 +46,6 @@ extension Instruction {
/// Operand: instruction address to branch to
case branch

/// Conditionally branch
///
/// condBranch(to: InstAddr, if: BoolReg)
///
/// Operands:
/// - Address to branch to
/// - Condition register to check
case condBranch

/// Conditionally branch if zero, otherwise decrement
///
/// condBranch(
Expand All @@ -85,39 +57,7 @@ extension Instruction {
///
case condBranchZeroElseDecrement

// MARK: General Purpose: Function calls

/// Push an instruction address to the stack
///
/// Operand: the instruction address
///
/// UNIMPLEMENTED
case push

/// Pop return address from call stack
///
/// UNIMPLEMENTED
case pop

/// Composite push-next-branch instruction
///
/// Operand: the function's start address
case call

/// Composite pop-branch instruction
///
/// Operand: the instruction address
///
/// NOTE: Currently, empty stack -> ACCEPT
case ret

// MARK: General Purpose: Debugging instructions

/// Print a string to the output
///
/// Operand: String register
case print

// TODO: Function calls

// MARK: - Matching

Expand All @@ -144,28 +84,11 @@ extension Instruction {
/// Operand: Sequence register to compare against.
case matchSequence

/// Match against a slice of the input
///
/// matchSlice(
/// lowerBound: PositionReg, upperBound: PositionReg)
///
/// Operands:
/// - Lowerbound position in the input
/// - Upperbound position in the input
case matchSlice

/// Save the current position in the input in a register
///
/// movePosition(into: PositionReg)
///
/// Operand: The position register to move into
case movePosition
/// TODO: builtin assertions and anchors
case builtinAssertion

/// Match against a provided element.
///
/// Operand: Packed condition register to write to and element register to
/// compare against.
case assertion
/// TODO: builtin character classes
case builtinCharacterClass

// MARK: Extension points

Expand Down Expand Up @@ -235,14 +158,6 @@ extension Instruction {
/// Precondition: The operand is in the save point list
case clearThrough

/// View the most recently saved point
///
/// UNIMPLEMENTED
case peek

/// Composite peek-branch-clear else FAIL
case restore

/// Fused save-and-branch.
///
/// split(to: target, saving: backtrackPoint)
Expand Down Expand Up @@ -290,17 +205,9 @@ extension Instruction {
/// Signal failure (currently same as `restore`)
case fail

/// Halt, fail, and signal failure
///
/// Operand: optional string register specifying the reason
///
/// TODO: Could have an Error existential area instead
case abort

// TODO: Fused assertions. It seems like we often want to
// branch based on assertion fail or success.


}
}

Expand Down Expand Up @@ -385,32 +292,17 @@ extension Instruction {

// TODO: replace with instruction formatters...
extension Instruction {
var stringRegister: StringRegister? {
switch opcode {
case .nop, .abort:
return payload.optionalString
case .print:
return payload.string
default: return nil
}
}
var instructionAddress: InstructionAddress? {
switch opcode {
case .branch, .save, .saveAddress, .call:
case .branch, .save, .saveAddress:
return payload.addr

case .condBranch:
return payload.pairedAddrBool.0

default: return nil
}
}
var elementRegister: ElementRegister? {
switch opcode {
case .match:
return payload.element
case .assertion:
return payload.pairedElementBool.0
default: return nil
}
}
Expand Down
111 changes: 1 addition & 110 deletions Sources/_StringProcessing/Engine/MEBuilder.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -17,7 +17,6 @@ extension MEProgram {

var elements = TypedSetVector<Input.Element, _ElementRegister>()
var sequences = TypedSetVector<[Input.Element], _SequenceRegister>()
var strings = TypedSetVector<String, _StringRegister>()

var consumeFunctions: [ConsumeFunction] = []
var assertionFunctions: [AssertionFunction] = []
Expand All @@ -29,9 +28,7 @@ extension MEProgram {
var addressFixups: [(InstructionAddress, AddressFixup)] = []

// Registers
var nextBoolRegister = BoolRegister(0)
var nextIntRegister = IntRegister(0)
var nextPositionRegister = PositionRegister(0)
var nextCaptureRegister = CaptureRegister(0)
var nextValueRegister = ValueRegister(0)

Expand Down Expand Up @@ -79,20 +76,6 @@ extension MEProgram.Builder {
.init(instructions.endIndex - 1)
}

mutating func buildNop(_ r: StringRegister? = nil) {
instructions.append(.init(.nop, .init(optionalString: r)))
}
mutating func buildNop(_ s: String) {
buildNop(strings.store(s))
}

mutating func buildDecrement(
_ i: IntRegister, nowZero: BoolRegister
) {
instructions.append(.init(
.decrement, .init(bool: nowZero, int: i)))
}

mutating func buildMoveImmediate(
_ value: UInt64, into: IntRegister
) {
Expand All @@ -108,24 +91,10 @@ extension MEProgram.Builder {
buildMoveImmediate(uint, into: into)
}

mutating func buildMoveCurrentPosition(
into: PositionRegister
) {
instructions.append(.init(
.movePosition, .init(position: into)))
}

mutating func buildBranch(to t: AddressToken) {
instructions.append(.init(.branch))
fixup(to: t)
}
mutating func buildCondBranch(
_ condition: BoolRegister, to t: AddressToken
) {
instructions.append(
.init(.condBranch, .init(bool: condition)))
fixup(to: t)
}

mutating func buildCondBranch(
to t: AddressToken, ifZeroElseDecrement i: IntRegister
Expand Down Expand Up @@ -157,27 +126,9 @@ extension MEProgram.Builder {
instructions.append(.init(.clearThrough))
fixup(to: t)
}
mutating func buildRestore() {
instructions.append(.init(.restore))
}
mutating func buildFail() {
instructions.append(.init(.fail))
}
mutating func buildCall(_ t: AddressToken) {
instructions.append(.init(.call))
fixup(to: t)
}
mutating func buildRet() {
instructions.append(.init(.ret))
}

mutating func buildAbort(_ s: StringRegister? = nil) {
instructions.append(.init(
.abort, .init(optionalString: s)))
}
mutating func buildAbort(_ s: String) {
buildAbort(strings.store(s))
}

mutating func buildAdvance(_ n: Distance) {
instructions.append(.init(.advance, .init(distance: n)))
Expand All @@ -196,14 +147,6 @@ extension MEProgram.Builder {
.init(sequence: sequences.store(.init(s)))))
}

mutating func buildMatchSlice(
lower: PositionRegister, upper: PositionRegister
) {
instructions.append(.init(
.matchSlice,
.init(pos: lower, pos2: upper)))
}

mutating func buildConsume(
by p: @escaping MEProgram.ConsumeFunction
) {
Expand All @@ -218,21 +161,10 @@ extension MEProgram.Builder {
.assertBy, .init(assertion: makeAssertionFunction(p))))
}

mutating func buildAssert(
_ e: Character, into cond: BoolRegister
) {
instructions.append(.init(.assertion, .init(
element: elements.store(e), bool: cond)))
}

mutating func buildAccept() {
instructions.append(.init(.accept))
}

mutating func buildPrint(_ s: StringRegister) {
instructions.append(.init(.print, .init(string: s)))
}

mutating func buildBeginCapture(
_ cap: CaptureRegister
) {
Expand Down Expand Up @@ -315,13 +247,10 @@ extension MEProgram.Builder {
let payload: Instruction.Payload

switch inst.opcode {
case .condBranch:
payload = .init(addr: addr, bool: inst.payload.bool)

case .condBranchZeroElseDecrement:
payload = .init(addr: addr, int: inst.payload.int)

case .branch, .save, .saveAddress, .call, .clearThrough:
case .branch, .save, .saveAddress, .clearThrough:
payload = .init(addr: addr)

case .splitSaving:
Expand All @@ -342,10 +271,7 @@ extension MEProgram.Builder {
var regInfo = MEProgram.RegisterInfo()
regInfo.elements = elements.count
regInfo.sequences = sequences.count
regInfo.strings = strings.count
regInfo.bools = nextBoolRegister.rawValue
regInfo.ints = nextIntRegister.rawValue
regInfo.positions = nextPositionRegister.rawValue
regInfo.values = nextValueRegister.rawValue
regInfo.consumeFunctions = consumeFunctions.count
regInfo.assertionFunctions = assertionFunctions.count
Expand All @@ -357,7 +283,6 @@ extension MEProgram.Builder {
instructions: InstructionList(instructions),
staticElements: elements.stored,
staticSequences: sequences.stored,
staticStrings: strings.stored,
staticConsumeFunctions: consumeFunctions,
staticAssertionFunctions: assertionFunctions,
staticTransformFunctions: transformFunctions,
Expand Down Expand Up @@ -468,18 +393,10 @@ extension MEProgram.Builder {
return nextCaptureRegister
}

mutating func makeBoolRegister() -> BoolRegister {
defer { nextBoolRegister.rawValue += 1 }
return nextBoolRegister
}
mutating func makeIntRegister() -> IntRegister {
defer { nextIntRegister.rawValue += 1 }
return nextIntRegister
}
mutating func makePositionRegister() -> PositionRegister {
defer { nextPositionRegister.rawValue += 1 }
return nextPositionRegister
}
mutating func makeValueRegister() -> ValueRegister {
defer { nextValueRegister.rawValue += 1 }
return nextValueRegister
Expand All @@ -494,32 +411,6 @@ extension MEProgram.Builder {
return r
}

// Allocate and initialize a register
mutating func makePositionRegister(
initializingWithCurrentPosition: ()
) -> PositionRegister {
let r = makePositionRegister()
self.buildMoveCurrentPosition(into: r)
return r
}

// 'kill' or release allocated registers
mutating func kill(_ r: IntRegister) {
// TODO: Release/reuse registers, for now nop makes
// reading the code easier
buildNop("kill \(r)")
}
mutating func kill(_ r: BoolRegister) {
// TODO: Release/reuse registers, for now nop makes
// reading the code easier
buildNop("kill \(r)")
}
mutating func kill(_ r: PositionRegister) {
// TODO: Release/reuse registers, for now nop makes
// reading the code easier
buildNop("kill \(r)")
}

// TODO: A register-mapping helper struct, which could release
// registers without monotonicity required

Expand Down
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