Add Knit directive to disable code gen of performance functions

Sources/KnitCodeGen/KnitDirectives.swift

@@ -11,13 +11,18 @@ public struct KnitDirectives: Codable, Equatable, Sendable {
     var moduleName: String?
     var spi: String?
 
+    /// When true the code gen will not create the additional methods to improve assembler performance
+    var disablePerformanceGen: Bool
+
     public init(
         accessLevel: AccessLevel? = nil,
+        disablePerformanceGen: Bool = false,
         getterConfig: Set<GetterConfig> = [],
         moduleName: String? = nil,
         spi: String? = nil
     ) {
         self.accessLevel = accessLevel
+        self.disablePerformanceGen = disablePerformanceGen
         self.getterConfig = getterConfig
         self.moduleName = moduleName
         self.spi = spi
@@ -56,6 +61,9 @@ public struct KnitDirectives: Codable, Equatable, Sendable {
             if let name = parsed.moduleName {
                 result.moduleName = name
             }
+            if parsed.disablePerformanceGen {
+                result.disablePerformanceGen = true
+            }
             for getter in parsed.getterConfig {
                 result.getterConfig.insert(getter)
             }
@@ -77,6 +85,9 @@ public struct KnitDirectives: Codable, Equatable, Sendable {
         if token == "getter-callAsFunction" {
             return KnitDirectives(getterConfig: [.callAsFunction])
         }
+        if token == "disable-performance-gen" {
+            return KnitDirectives(disablePerformanceGen: true)
+        }
         if let nameMatch = getterNamedRegex.firstMatch(in: token, range: NSMakeRange(0, token.count)) {
             if nameMatch.numberOfRanges >= 2, nameMatch.range(at: 1).location != NSNotFound {
                 var range = nameMatch.range(at: 1)

Sources/KnitCodeGen/TypeSafetySourceFile.swift

@@ -46,7 +46,9 @@ public enum TypeSafetySourceFile {
             if let defaultOverrides = try makeDefaultOverrideExtensions(config: config) {
                 defaultOverrides
             }
-            try makePerformanceExtension(config: config)
+            if !config.directives.disablePerformanceGen {
+                try makePerformanceExtension(config: config)
+            }
         }
     }
 

Tests/KnitCodeGenTests/ConfigurationSetTests.swift

@@ -365,6 +365,42 @@ final class ConfigurationSetTests: XCTestCase {
         XCTAssertNoThrow(try configSet.validateNoDuplicateRegistrations())
     }
 
+    func testPerformanceGenDisabled() {
+        let config = Configuration(
+            assemblyName: "CustomAssembly",
+            moduleName: "Custom",
+            directives: .init(disablePerformanceGen: true),
+            registrations: [
+                .init(service: "Service1", accessLevel: .internal)
+            ],
+            targetResolver: "Resolver"
+        )
+        let configSet = ConfigurationSet(
+            assemblies: [config],
+            externalTestingAssemblies: [],
+            moduleDependencies: []
+        )
+
+        XCTAssertEqual(
+            try configSet.makeTypeSafetySourceFile(),
+            """
+            // Generated using Knit
+            // Do not edit directly!
+
+            import Knit
+
+            // The correct resolution of each of these types is enforced by a matching automated unit test
+            // If a type registration is missing or broken then the automated tests will fail for that PR
+            /// Generated from ``CustomAssembly``
+            extension Resolver {
+                func service1(file: StaticString = #fileID, function: StaticString = #function, line: UInt = #line) -> Service1 {
+                    knitUnwrap(resolve(Service1.self), callsiteFile: file, callsiteFunction: function, callsiteLine: line)
+                }
+            }
+            """
+        )
+    }
+
 }
 
 private enum Factory {

Tests/KnitCodeGenTests/KnitDirectivesTests.swift

@@ -121,6 +121,13 @@ final class KnitDirectivesTests: XCTestCase {
         XCTAssertThrowsError(try parse("// @knit module-name()"))
     }
 
+    func testPerformanceGen() {
+        XCTAssertEqual(
+            try parse("// @knit disable-performance-gen"),
+            .init(disablePerformanceGen: true)
+        )
+    }
+
     private func parse(_ comment: String) throws -> KnitDirectives {
         let trivia = Trivia(pieces: [.lineComment(comment)])
         return try KnitDirectives.parse(leadingTrivia: trivia)