[cxx-interop] Add driver support for -emit-clang-header-min-access

This is a counterpart to swiftlang/swift#84816.

rdar://159211965

Author: egorzhdan

Sources/SwiftDriver/Jobs/FrontendJobHelpers.swift

@@ -378,6 +378,8 @@ extension Driver {
       try commandLine.appendLast(.clangBuildSessionFile, from: &parsedOptions)
     }
 
+    try commandLine.appendLast(.emitClangHeaderMinAccess, from: &parsedOptions)
+
     if isFrontendArgSupported(.enableBuiltinModule) {
       try commandLine.appendLast(.enableBuiltinModule, from: &parsedOptions)
     }

Sources/SwiftOptions/Options.swift

@@ -341,6 +341,7 @@ extension Option {
   public static let emitBc: Option = Option("-emit-bc", .flag, attributes: [.frontend, .noInteractive, .doesNotAffectIncrementalBuild], helpText: "Emit LLVM BC file(s)", group: .modes)
   public static let emitClangHeaderNonmodularIncludes: Option = Option("-emit-clang-header-nonmodular-includes", .flag, attributes: [.frontend, .noInteractive, .supplementaryOutput], helpText: "Augment emitted Objective-C header with textual imports for every included modular import")
   public static let emitClangHeaderPath: Option = Option("-emit-clang-header-path", .separate, alias: Option.emitObjcHeaderPath, attributes: [.frontend, .noInteractive, .argumentIsPath, .supplementaryOutput, .cacheInvariant], helpText: "Emit an Objective-C and C++ header file to <path>")
+  public static let emitClangHeaderMinAccess: Option = Option("-emit-clang-header-min-access", .separate, attributes: [.frontend, .noInteractive, .cacheInvariant], metaVar: "<access-level>", helpText: "The minimum access level of declarations to include in the emitted header")
   public static let emitConstValuesPath: Option = Option("-emit-const-values-path", .separate, attributes: [.frontend, .noInteractive, .argumentIsPath, .supplementaryOutput, .cacheInvariant], metaVar: "<path>", helpText: "Emit the extracted compile-time known values to <path>")
   public static let emitConstValues: Option = Option("-emit-const-values", .flag, attributes: [.noInteractive, .supplementaryOutput])
   public static let emitDependenciesPath: Option = Option("-emit-dependencies-path", .separate, attributes: [.frontend, .noDriver, .cacheInvariant], metaVar: "<path>", helpText: "Output basic Make-compatible dependencies file to <path>")
@@ -1311,6 +1312,7 @@ extension Option {
       Option.emitBc,
       Option.emitClangHeaderNonmodularIncludes,
       Option.emitClangHeaderPath,
+      Option.emitClangHeaderMinAccess,
       Option.emitConstValuesPath,
       Option.emitConstValues,
       Option.emitDependenciesPath,

Tests/SwiftDriverTests/SwiftDriverTests.swift

@@ -7639,6 +7639,16 @@ final class SwiftDriverTests: XCTestCase {
       try XCTAssertJobInvocationMatches(jobs[0], .flag("-emit-objc-header-path"), toPathOption("path/to/header"))
   }
 
+  func testEmitClangHeaderMinAccess() throws {
+      VirtualPath.resetTemporaryFileStore()
+      var driver = try Driver(args: [
+        "swiftc", "-emit-clang-header-path", "path/to/header", "-emit-clang-header-min-access", "public", "-typecheck", "test.swift"
+      ])
+      let jobs = try driver.planBuild().removingAutolinkExtractJobs()
+      XCTAssertEqual(jobs.count, 2)
+      try XCTAssertJobInvocationMatches(jobs[0], .flag("-emit-clang-header-min-access"), .flag("public"))
+  }
+
   func testGccToolchainFlags() throws {
       VirtualPath.resetTemporaryFileStore()
       var driver = try Driver(args: [