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/// > Note:
/// <https://webassembly.github.io/spec/core/exec/instructions.html#table-instructions>
extension ExecutionState {
mutating func tableGet(runtime: Runtime, tableIndex: TableIndex) throws {
let (_, table) = getTable(tableIndex, store: runtime.store)
let elementIndex = try getElementIndex(table)
guard let reference = table.elements[Int(elementIndex)] else {
throw Trap.readingDroppedReference(index: elementIndex)
}
stack.push(value: .ref(reference))
}
mutating func tableSet(runtime: Runtime, tableIndex: TableIndex) throws {
let (tableAddress, table) = getTable(tableIndex, store: runtime.store)
let reference = stack.getReference()
let elementIndex = try getElementIndex(table)
setTableElement(store: runtime.store, tableAddress: tableAddress, elementIndex, reference)
}
mutating func tableSize(runtime: Runtime, tableIndex: TableIndex) {
let (_, table) = getTable(tableIndex, store: runtime.store)
stack.push(value: .i32(UInt32(table.elements.count)))
}
mutating func tableGrow(runtime: Runtime, tableIndex: TableIndex) {
let (tableAddress, table) = getTable(tableIndex, store: runtime.store)
let growthSize = stack.popValue()
guard case let .i32(growthSize) = growthSize else {
fatalError("invalid value at the top of the stack \(growthSize)")
}
let growthValue = stack.getReference()
let oldSize = UInt32(table.elements.count)
guard runtime.store.tables[tableAddress].grow(by: growthSize, value: growthValue) else {
stack.push(value: .i32(Int32(-1).unsigned))
return
}
stack.push(value: .i32(oldSize))
}
mutating func tableFill(runtime: Runtime, tableIndex: TableIndex) throws {
let (tableAddress, table) = getTable(tableIndex, store: runtime.store)
let fillCounter = stack.popValue().i32
let fillValue = stack.getReference()
let startIndex = stack.popValue().i32
guard fillCounter > 0 else {
return
}
guard Int(startIndex + fillCounter) <= table.elements.count else {
throw Trap.outOfBoundsTableAccess(index: startIndex + fillCounter)
}
for i in 0..<fillCounter {
setTableElement(store: runtime.store, tableAddress: tableAddress, startIndex + i, fillValue)
}
}
mutating func tableCopy(runtime: Runtime, dest destinationTableIndex: TableIndex, src sourceTableIndex: TableIndex) throws {
let (_, sourceTable) = getTable(sourceTableIndex, store: runtime.store)
let (destinationTableAddress, destinationTable) = getTable(destinationTableIndex, store: runtime.store)
let copyCounter = stack.popValue().i32
let sourceIndex = stack.popValue().i32
let destinationIndex = stack.popValue().i32
guard copyCounter > 0 else {
return
}
guard
!sourceIndex.addingReportingOverflow(copyCounter).overflow && !destinationIndex.addingReportingOverflow(copyCounter).overflow
else {
throw Trap.tableSizeOverflow
}
guard destinationIndex + copyCounter <= sourceTable.elements.count else {
throw Trap.outOfBoundsTableAccess(index: destinationIndex + copyCounter)
}
guard destinationIndex + copyCounter <= sourceTable.elements.count && sourceIndex + copyCounter <= destinationTable.elements.count else {
throw Trap.outOfBoundsTableAccess(index: destinationIndex + copyCounter)
}
for i in 0..<copyCounter {
setTableElement(
store: runtime.store,
tableAddress: destinationTableAddress,
destinationIndex + i,
sourceTable.elements[Int(sourceIndex + i)]
)
}
}
mutating func tableInit(runtime: Runtime, tableIndex: TableIndex, elementIndex: ElementIndex) throws {
let (destinationTableAddress, destinationTable) = getTable(tableIndex, store: runtime.store)
let elementAddress = currentModule(store: runtime.store).elementAddresses[Int(elementIndex)]
let sourceElement = runtime.store.elements[elementAddress]
let copyCounter = stack.popValue().i32
let sourceIndex = stack.popValue().i32
let destinationIndex = stack.popValue().i32
guard copyCounter > 0 else {
return
}
guard
!sourceIndex.addingReportingOverflow(copyCounter).overflow && !destinationIndex.addingReportingOverflow(copyCounter).overflow
else {
throw Trap.tableSizeOverflow
}
guard sourceIndex + copyCounter <= sourceElement.references.count else {
throw Trap.outOfBoundsTableAccess(index: sourceIndex + copyCounter)
}
guard destinationIndex + copyCounter <= destinationTable.elements.count else {
throw Trap.outOfBoundsTableAccess(index: destinationIndex + copyCounter)
}
for i in 0..<copyCounter {
let reference = sourceElement.references[Int(sourceIndex + i)]
setTableElement(
store: runtime.store,
tableAddress: destinationTableAddress,
destinationIndex + i,
reference
)
}
}
mutating func tableElementDrop(runtime: Runtime, elementIndex: ElementIndex) {
let elementAddress = currentModule(store: runtime.store).elementAddresses[Int(elementIndex)]
runtime.store.elements[elementAddress].drop()
}
fileprivate func setTableElement(
store: Store,
tableAddress: TableAddress,
_ elementIndex: ElementIndex,
_ reference: Reference?
) {
store.tables[tableAddress].elements[Int(elementIndex)] = reference
}
}
extension ExecutionState {
fileprivate func getTable(_ tableIndex: UInt32, store: Store) -> (TableAddress, TableInstance) {
let address = currentModule(store: store).tableAddresses[Int(tableIndex)]
return (address, store.tables[address])
}
fileprivate mutating func getElementIndex(_ table: TableInstance) throws -> ElementIndex {
let elementIndex = stack.popValue().i32
guard elementIndex < table.elements.count else {
throw Trap.outOfBoundsTableAccess(index: elementIndex)
}
return elementIndex
}
}
extension Stack {
fileprivate mutating func getReference() -> Reference {
let value = popValue()
guard case let .ref(reference) = value else {
fatalError("invalid value at the top of the stack \(value)")
}
return reference
}
}
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