Add tests for numThreads and numParallelJobs. Diagnose trying to multithread batch mode.

Author: sjavora

Sources/SwiftDriver/Driver/Driver.swift

@@ -466,7 +466,7 @@ extension Diagnostic.Message {
     .error("-driver-use-frontend-path requires a Swift compiler executable argument")
   }
 
-  static var warning_cannot_multithread_batch_mode: Diagnostic.Message {
+  public static var warning_cannot_multithread_batch_mode: Diagnostic.Message {
     .warning("ignoring -num-threads argument; cannot multithread batch mode")
   }
 }
@@ -731,17 +731,14 @@ extension Driver {
 
     // Make sure we have a non-negative integer value.
     guard let numThreads = Int(numThreadsArg.asSingle), numThreads >= 0 else {
-      diagnosticsEngine.emit(Diagnostic.Message.error_invalid_arg_value(arg: .numThreads, value: numThreadsArg.asSingle))
+      diagnosticsEngine.emit(.error_invalid_arg_value(arg: .numThreads, value: numThreadsArg.asSingle))
       return 0
     }
 
-    #if false
-    // FIXME: Check for batch mode.
-    if false {
+    if case .batchCompile = compilerMode {
       diagnosticsEngine.emit(.warning_cannot_multithread_batch_mode)
       return 0
     }
-    #endif
 
     return numThreads
   }
@@ -771,7 +768,7 @@ extension Driver {
 }
 
 extension Diagnostic.Message {
-  static func remark_max_determinism_overriding(_ option: Option) -> Diagnostic.Message {
+  public static func remark_max_determinism_overriding(_ option: Option) -> Diagnostic.Message {
     .remark("SWIFTC_MAXIMUM_DETERMINISM overriding \(option.spelling)")
   }
 }

Tests/SwiftDriverTests/SwiftDriverTests.swift

@@ -148,6 +148,46 @@ final class SwiftDriverTests: XCTestCase {
       }
   }
 
+    func testMultithreading() throws {
+
+        XCTAssertEqual(try Driver(args: ["swiftc"]).numThreads, 0)
+
+        XCTAssertEqual(try Driver(args: ["swiftc", "-num-threads", "4"]).numThreads, 4)
+
+        XCTAssertEqual(try Driver(args: ["swiftc", "-num-threads", "0"]).numThreads, 0)
+
+        XCTAssertEqual(try Driver(args: ["swiftc", "-num-threads", "-1"]).numThreads, 0)
+
+        XCTAssertEqual(try Driver(args: ["swiftc", "-enable-batch-mode", "-num-threads", "4"]).numThreads, 0)
+
+        XCTAssertNil(try Driver(args: ["swiftc"]).numParallelJobs)
+
+        XCTAssertEqual(try Driver(args: ["swiftc", "-j", "4"]).numParallelJobs, 4)
+
+        XCTAssertNil(try Driver(args: ["swiftc", "-j", "0"]).numParallelJobs)
+
+        XCTAssertEqual(try Driver(args: ["swiftc", "-j", "4"], env: ["SWIFTC_MAXIMUM_DETERMINISM": "1"]).numParallelJobs, 1)
+    }
+
+    func testMultithreadingDiagnostics() throws {
+
+        try assertDriverDiagnostics(args: "swift", "-num-threads", "-1") {
+            $1.expect(.error_invalid_arg_value(arg: .numThreads, value: "-1"))
+        }
+
+        try assertDriverDiagnostics(args: "swiftc", "-enable-batch-mode", "-num-threads", "4") {
+            $1.expect(.warning_cannot_multithread_batch_mode)
+        }
+
+        try assertDriverDiagnostics(args: "swiftc", "-j", "0") {
+            $1.expect(.error_invalid_arg_value(arg: .j, value: "0"))
+        }
+
+        try assertDriverDiagnostics(args: "swiftc", "-j", "8", env: ["SWIFTC_MAXIMUM_DETERMINISM": "1"]) {
+            $1.expect(.remark_max_determinism_overriding(.j))
+        }
+    }
+
   func testDebugSettings() throws {
     try assertNoDriverDiagnostics(args: "swiftc", "foo.swift", "-emit-module") { driver in
       XCTAssertNil(driver.debugInfoLevel)