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[nfc] Avoid pointer conversions #691

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Merged
merged 3 commits into from
Sep 1, 2023
Merged

[nfc] Avoid pointer conversions #691

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d45027b
adopt the stdlib’s pattern for atomic lazy references
glessard Aug 31, 2023
74637cc
pass a pointer instead of inout conversion
glessard Aug 31, 2023
bc70423
Update Sources/_StringProcessing/Regex/Core.swift
glessard Aug 31, 2023
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19 changes: 14 additions & 5 deletions Sources/_StringProcessing/Regex/Core.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -126,6 +126,13 @@ extension Regex {
/// A program representation that caches any lowered representation for
/// execution.
internal final class Program {

// This stored property should be stored at offset zero. We perform atomic
// operations on it.
//
/// Do not access this property directly - all accesses must go through `_loweredProgramStoragePtr `.
fileprivate var _loweredProgramStorage: AnyObject? = nil

/// The underlying IR.
///
/// FIXME: If Regex is the unit of composition, then it should be a Node instead,
Expand All @@ -141,14 +148,16 @@ extension Regex {
init(_ value: MEProgram) { self.value = value }
}

/// Do not use directly - all accesses must go through `loweredProgram`.
fileprivate var _loweredProgramStorage: AnyObject? = nil

fileprivate var _loweredProgramStoragePtr: UnsafeMutablePointer<AnyObject?> {
_getUnsafePointerToStoredProperties(self)
.assumingMemoryBound(to: Optional<AnyObject>.self)
}

/// The program for execution with the matching engine.
var loweredProgram: MEProgram {
/// Atomically loads the compiled program if it has already been stored.
func loadProgram() -> MEProgram? {
guard let loweredObject = _stdlib_atomicLoadARCRef(object: &_loweredProgramStorage)
guard let loweredObject = _stdlib_atomicLoadARCRef(object: _loweredProgramStoragePtr)
else { return nil }
return unsafeDowncast(loweredObject, to: ProgramBox.self).value
}
Expand All @@ -161,7 +170,7 @@ extension Regex {
// Compile the DSLTree into a lowered program and store it atomically.
let compiledProgram = try! Compiler(tree: tree, compileOptions: compileOptions).emit()
let storedNewProgram = _stdlib_atomicInitializeARCRef(
object: &_loweredProgramStorage,
object: _loweredProgramStoragePtr,
desired: ProgramBox(compiledProgram))

// Return the winner of the storage race. We're guaranteed at this point
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6 changes: 4 additions & 2 deletions Sources/_StringProcessing/Unicode/ScalarProps.swift
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Expand Up @@ -29,8 +29,10 @@ extension Unicode.Script {

static func extensions(for scalar: Unicode.Scalar) -> [Unicode.Script] {
var count: UInt8 = 0
let pointer = _swift_string_processing_getScriptExtensions(scalar.value, &count)

let pointer = withUnsafeMutablePointer(to: &count) {
_swift_string_processing_getScriptExtensions(scalar.value, $0)
}

guard let pointer = pointer else {
return [Unicode.Script(scalar)]
}
Expand Down