SwiftBuild: Add index store support

Update the PIF builder to take into account of the
`--[auto|disable|enable]-index-store` command line option.

When set to `auto`, the PIF builder behaviour does the same as the
Native build system.

Fixes: swiftlang#9325
Issue: rdar://163961900

Author: bkhouri

Fixtures/PIFBuilder/Simple/.gitignore

@@ -0,0 +1,8 @@
+.DS_Store
+/.build
+/Packages
+xcuserdata/
+DerivedData/
+.swiftpm/configuration/registries.json
+.swiftpm/xcode/package.xcworkspace/contents.xcworkspacedata
+.netrc

Fixtures/PIFBuilder/Simple/Package.swift

@@ -0,0 +1,26 @@
+// swift-tools-version: 6.2
+// The swift-tools-version declares the minimum version of Swift required to build this package.
+
+import PackageDescription
+
+let package = Package(
+    name: "Simple",
+    products: [
+        // Products define the executables and libraries a package produces, making them visible to other packages.
+        .library(
+            name: "Simple",
+            targets: ["Simple"]
+        ),
+    ],
+    targets: [
+        // Targets are the basic building blocks of a package, defining a module or a test suite.
+        // Targets can depend on other targets in this package and products from dependencies.
+        .target(
+            name: "Simple"
+        ),
+        .testTarget(
+            name: "SimpleTests",
+            dependencies: ["Simple"]
+        ),
+    ]
+)

Fixtures/PIFBuilder/Simple/Sources/Simple/Simple.swift

@@ -0,0 +1,25 @@
+// The Swift Programming Language
+// https://docs.swift.org/swift-book
+
+public struct Person {
+    public let name: String
+
+    public init(name: String) {
+        self.name = name
+    }
+}
+extension Person: CustomStringConvertible {
+    public var description: String {
+        return name
+    }
+}
+
+public func greet(person: Person? = nil) -> String {
+    let name = if let person {
+        person.name
+    } else {
+        "World"
+    }
+
+    return "Hello, \(name)!"
+}

Fixtures/PIFBuilder/Simple/Tests/SimpleTests/SimpleTests.swift

@@ -0,0 +1,36 @@
+import Testing
+import XCTest
+
+import Simple
+
+
+final public class XCTesting: XCTestCase {
+    func testGreetWithEmptyArgument() {
+        let actual = greet()
+        XCTAssertEqual(actual, "Hello, World!")
+    }
+
+    func testGreetWithNonEmptyArgument() {
+        let name = "MyName"
+        let person = Person(name: name)
+        let actual = greet(person: person)
+        XCTAssertEqual(actual, "Hello, \(name)!")
+    }
+}
+
+@Suite
+struct STTestTests {
+    @Test("STTest tests")
+    func testGreetWithEmptyArgument() {
+        let actual = greet()
+        #expect(actual == "Hello, World!")
+    }
+
+    @Test("STTest tests")
+    func testGreetWithNonEmptyArgument() {
+        let name = "MyName"
+        let person = Person(name: name)
+        let actual = greet(person: person)
+        #expect(actual == "Hello, \(name)!")
+    }
+}

Sources/PackageModel/SwiftSDKs/SwiftSDK.swift

@@ -609,7 +609,7 @@ public struct SwiftSDK: Equatable {
         extraCCFlags += ["-fPIC"]
         #endif
 
-        return SwiftSDK(
+        let returnValue = SwiftSDK(
             toolset: .init(
                 knownTools: [
                     .cCompiler: .init(extraCLIOptions: extraCCFlags),
@@ -620,6 +620,7 @@ public struct SwiftSDK: Equatable {
             pathsConfiguration: .init(sdkRootPath: sdkPath),
             xctestSupport: xctestSupport
         )
+        return returnValue
     }
 
     /// Auxiliary platform frameworks and libraries.

Sources/SPMBuildCore/BuildParameters/BuildParameters.swift

@@ -29,7 +29,7 @@ public struct BuildParameters: Encodable {
     }
 
     /// Mode for the indexing-while-building feature.
-    public enum IndexStoreMode: String, Encodable {
+    public enum IndexStoreMode: String, Encodable, CaseIterable {
         /// Index store should be enabled.
         case on
         /// Index store should be disabled.

Sources/SwiftBuildSupport/PackagePIFBuilder.swift

@@ -32,6 +32,8 @@ import struct PackageGraph.ModulesGraph
 import struct PackageGraph.ResolvedModule
 import struct PackageGraph.ResolvedPackage
 
+import struct SPMBuildCore.BuildParameters
+
 import enum SwiftBuild.ProjectModel
 
 typealias GUID = SwiftBuild.ProjectModel.GUID
@@ -203,7 +205,7 @@ public final class PackagePIFBuilder {
         addLocalRpaths: Bool = true,
         packageDisplayVersion: String?,
         fileSystem: FileSystem,
-        observabilityScope: ObservabilityScope
+        observabilityScope: ObservabilityScope,
     ) {
         self.package = resolvedPackage
         self.packageManifest = packageManifest
@@ -227,7 +229,7 @@ public final class PackagePIFBuilder {
         addLocalRpaths: Bool = true,
         packageDisplayVersion: String?,
         fileSystem: FileSystem,
-        observabilityScope: ObservabilityScope
+        observabilityScope: ObservabilityScope,
     ) {
         self.package = resolvedPackage
         self.packageManifest = packageManifest
@@ -438,7 +440,7 @@ public final class PackagePIFBuilder {
         //
 
         self.log(.debug, "Processing \(package.products.count) products:")
-        
+
         // For each of the **products** in the package we create a corresponding `PIFTarget` of the appropriate type.
         for product in self.package.products {
             switch product.type {
@@ -561,8 +563,8 @@ public final class PackagePIFBuilder {
         // We currently deliberately do not support Swift ObjC interface headers.
         settings[.SWIFT_INSTALL_OBJC_HEADER] = "NO"
         settings[.SWIFT_OBJC_INTERFACE_HEADER_NAME] = ""
-        
-        // rdar://47937899 (Don't try to link frameworks to object files) 
+
+        // rdar://47937899 (Don't try to link frameworks to object files)
         //  - looks like this defaults to OTHER_LDFLAGS (via xcspec) which can result in linking frameworks to mh_objects which is unwanted.
         settings[.OTHER_LDRFLAGS] = []
 
@@ -622,6 +624,7 @@ public final class PackagePIFBuilder {
         debugSettings[.ENABLE_TESTABILITY] = "YES"
         debugSettings[.SWIFT_ACTIVE_COMPILATION_CONDITIONS, default: []].append(contentsOf: ["DEBUG"])
         debugSettings[.GCC_PREPROCESSOR_DEFINITIONS, default: ["$(inherited)"]].append(contentsOf: ["DEBUG=1"])
+        debugSettings[.SWIFT_INDEX_STORE_ENABLE] = "YES"
         builder.project.addBuildConfig { id in BuildConfig(id: id, name: "Debug", settings: debugSettings) }
 
         // Add the build settings that are specific to release builds, and set those as the "Release" configuration.

Sources/SwiftBuildSupport/SwiftBuildSystem.swift

@@ -43,7 +43,7 @@ struct SessionFailedError: Error {
     var diagnostics: [SwiftBuild.SwiftBuildMessage.DiagnosticInfo]
 }
 
-func withService<T>(
+package func withService<T>(
     connectionMode: SWBBuildServiceConnectionMode = .default,
     variant: SWBBuildServiceVariant = .default,
     serviceBundleURL: URL? = nil,
@@ -860,7 +860,11 @@ public final class SwiftBuildSystem: SPMBuildCore.BuildSystem {
         )
     }
 
-    private func makeBuildParameters(session: SWBBuildServiceSession, symbolGraphOptions: BuildOutput.SymbolGraphOptions?) async throws -> SwiftBuild.SWBBuildParameters {
+    internal func makeBuildParameters(
+        session: SWBBuildServiceSession,
+        symbolGraphOptions: BuildOutput.SymbolGraphOptions?,
+        setToolchainSetting: Bool = true,
+    ) async throws -> SwiftBuild.SWBBuildParameters {
         // Generate the run destination parameters.
         let runDestination = makeRunDestination()
 
@@ -872,17 +876,19 @@ public final class SwiftBuildSystem: SPMBuildCore.BuildSystem {
         // Generate a table of any overriding build settings.
         var settings: [String: String] = [:]
 
-        // If the SwiftPM toolchain corresponds to a toolchain registered with the lower level build system, add it to the toolchain stack.
-        // Otherwise, apply overrides for each component of the SwiftPM toolchain.
-        if let toolchainID = try await session.lookupToolchain(at: buildParameters.toolchain.toolchainDir.pathString) {
-            settings["TOOLCHAINS"] = "\(toolchainID.rawValue) $(inherited)"
-        } else {
-            // FIXME: This list of overrides is incomplete.
-            // An error with determining the override should not be fatal here.
-            settings["CC"] = try? buildParameters.toolchain.getClangCompiler().pathString
-            // Always specify the path of the effective Swift compiler, which was determined in the same way as for the
-            // native build system.
-            settings["SWIFT_EXEC"] = buildParameters.toolchain.swiftCompilerPath.pathString
+        if setToolchainSetting {
+            // If the SwiftPM toolchain corresponds to a toolchain registered with the lower level build system, add it to the toolchain stack.
+            // Otherwise, apply overrides for each component of the SwiftPM toolchain.
+            if let toolchainID = try await session.lookupToolchain(at: buildParameters.toolchain.toolchainDir.pathString) {
+                settings["TOOLCHAINS"] = "\(toolchainID.rawValue) $(inherited)"
+            } else {
+                // FIXME: This list of overrides is incomplete.
+                // An error with determining the override should not be fatal here.
+                settings["CC"] = try? buildParameters.toolchain.getClangCompiler().pathString
+                // Always specify the path of the effective Swift compiler, which was determined in the same way as for the
+                // native build system.
+                settings["SWIFT_EXEC"] = buildParameters.toolchain.swiftCompilerPath.pathString
+            }
         }
 
         // FIXME: workaround for old Xcode installations such as what is in CI
@@ -985,6 +991,38 @@ public final class SwiftBuildSystem: SPMBuildCore.BuildSystem {
             settings["GENERATE_TEST_ENTRYPOINTS_FOR_BUNDLES"] = "YES"
         }
 
+        // Set the value of the index store
+        struct IndexStoreSettings {
+            let enableVariableName: String
+            let pathVariable: String
+        }
+
+        let indexStoreSettingNames: [IndexStoreSettings] = [
+            IndexStoreSettings(
+                enableVariableName: "CLANG_INDEX_STORE_ENABLE",
+                pathVariable: "CLANG_INDEX_STORE_PATH",
+            ),
+            IndexStoreSettings(
+                enableVariableName: "SWIFT_INDEX_STORE_ENABLE",
+                pathVariable: "SWIFT_INDEX_STORE_PATH",
+            ),
+        ]
+
+        switch self.buildParameters.indexStoreMode {
+        case .on:
+            for setting in indexStoreSettingNames {
+                settings[setting.enableVariableName] = "YES"
+                settings[setting.pathVariable] = self.buildParameters.indexStore.pathString
+            }
+        case .off:
+            for setting in indexStoreSettingNames {
+                settings[setting.enableVariableName] = "NO"
+            }
+        case .auto:
+            // The settings are handles in the PIF builder
+            break
+        }
+
         func reportConflict(_ a: String, _ b: String) throws -> String {
             throw StringError("Build parameters constructed conflicting settings overrides '\(a)' and '\(b)'")
         }
@@ -1223,13 +1261,13 @@ fileprivate extension SwiftBuild.SwiftBuildMessage.DiagnosticInfo.Location {
             case .none:
                 return path
             }
-        
+
         case .buildSettings(let names):
             return names.joined(separator: ", ")
-        
+
         case .buildFiles(let buildFiles, let targetGUID):
             return "\(targetGUID): " + buildFiles.map { String(describing: $0) }.joined(separator: ", ")
-            
+
         case .unknown:
             return nil
         }

Sources/_InternalTestSupport/MockBuildTestHelper.swift

@@ -87,7 +87,7 @@ public func mockBuildParameters(
     shouldDisableLocalRpath: Bool = false,
     canRenameEntrypointFunctionName: Bool = false,
     triple: Basics.Triple = hostTriple,
-    indexStoreMode: BuildParameters.IndexStoreMode = .off,
+    indexStoreMode: BuildParameters.IndexStoreMode = .auto,
     linkerDeadStrip: Bool = true,
     linkTimeOptimizationMode: BuildParameters.LinkTimeOptimizationMode? = nil,
     omitFramePointers: Bool? = nil,

Sources/_InternalTestSupport/SwiftTesting+Tags.swift

@@ -14,6 +14,7 @@ extension Tag {
     public enum TestSize {}
     public enum Feature {}
     public enum Platform {}
+    public enum FunctionalArea {}
     @Tag public static var UserWorkflow: Tag
 }
 
@@ -191,3 +192,8 @@ extension Tag.Feature.Product {
     @Tag public static var Execute: Tag
     @Tag public static var Link: Tag
 }
+
+extension Tag.FunctionalArea {
+    @Tag public static var PIF: Tag
+    @Tag public static var IndexMode: Tag
+}