Bump the DWARF version number to 5 on Darwin.

The default debug info format for newer versions of Darwin is DWARF 5.

https://developer.apple.com/documentation/xcode-release-notes/xcode-16-release-notes

rdar://110925733
(cherry picked from commit c5ad78c)

Author: adrian-prantl

Sources/SwiftDriver/Toolchains/DarwinToolchain.swift

@@ -220,12 +220,25 @@ public final class DarwinToolchain: Toolchain {
   }
 
   public func getDefaultDwarfVersion(targetTriple: Triple) -> UInt8 {
-      if (targetTriple.isMacOSX && targetTriple.version(for: .macOS) < Triple.Version(10, 11, 0)) ||
+    // Default to DWARF 2 on OS X 10.10 / iOS 8 and lower.
+    // Default to DWARF 4 on OS X 10.11 - macOS 14 / iOS - iOS 17.
+    if (targetTriple.isMacOSX && targetTriple.version(for: .macOS) < Triple.Version(10, 11, 0)) ||
         (targetTriple.isiOS && targetTriple.version(
             for: .iOS(targetTriple._isSimulatorEnvironment ? .simulator : .device)) < Triple.Version(9, 0, 0)) {
       return 2;
     }
-    return 4
+    if (targetTriple.isMacOSX && targetTriple.version(for: .macOS) < Triple.Version(15, 0, 0)) ||
+        (targetTriple.isiOS && targetTriple.version(
+            for: .iOS(targetTriple._isSimulatorEnvironment ? .simulator : .device)) < Triple.Version(18, 0, 0)) ||
+        (targetTriple.isTvOS && targetTriple.version(
+            for: .tvOS(targetTriple._isSimulatorEnvironment ? .simulator : .device)) < Triple.Version(18, 0, 0)) ||
+        (targetTriple.isWatchOS && targetTriple.version(
+            for: .watchOS(targetTriple._isSimulatorEnvironment ? .simulator : .device)) < Triple.Version(11, 0, 0)) ||
+        (targetTriple.isVisionOS && targetTriple.version(
+            for: .visionOS(targetTriple._isSimulatorEnvironment ? .simulator : .device)) < Triple.Version(2, 0, 0)){
+      return 4
+    }
+    return 5
   }
 
   func validateDeploymentTarget(_ parsedOptions: inout ParsedOptions,

Tests/SwiftDriverTests/SwiftDriverTests.swift

@@ -661,15 +661,35 @@ final class SwiftDriverTests: XCTestCase {
       XCTAssertTrue(jobs[0].commandLine.contains(.flag("-dwarf-version=4")))
     }
 
-    // TODO: Enable once compiler support lands
-//    try assertNoDriverDiagnostics(args: "swiftc", "foo.swift", "-g", "-c", "-target", "arm64-apple-xros1.0-simulator") { driver in
-//      let jobs = try driver.planBuild()
-//      XCTAssertTrue(jobs[0].commandLine.contains(.flag("-dwarf-version=4")))
-//    }
-//    try assertNoDriverDiagnostics(args: "swiftc", "foo.swift", "-g", "-c", "-target", "arm64-apple-xros1.0") { driver in
-//      let jobs = try driver.planBuild()
-//      XCTAssertTrue(jobs[0].commandLine.contains(.flag("-dwarf-version=4")))
-//    }
+    try assertNoDriverDiagnostics(args: "swiftc", "foo.swift", "-g", "-c", "-target", "x86_64-apple-macosx15") { driver in
+      let jobs = try driver.planBuild()
+      XCTAssertTrue(jobs[0].commandLine.contains(.flag("-dwarf-version=5")))
+    }
+    try assertNoDriverDiagnostics(args: "swiftc", "foo.swift", "-g", "-c", "-target", "arm64-apple-ios18.0") { driver in
+      let jobs = try driver.planBuild()
+      XCTAssertTrue(jobs[0].commandLine.contains(.flag("-dwarf-version=5")))
+    }
+    try assertNoDriverDiagnostics(args: "swiftc", "foo.swift", "-g", "-c", "-target", "arm64_32-apple-watchos11") { driver in
+      let jobs = try driver.planBuild()
+      XCTAssertTrue(jobs[0].commandLine.contains(.flag("-dwarf-version=5")))
+    }
+    try assertNoDriverDiagnostics(args: "swiftc", "foo.swift", "-g", "-c", "-target", "arm64-apple-tvos18") { driver in
+      let jobs = try driver.planBuild()
+      XCTAssertTrue(jobs[0].commandLine.contains(.flag("-dwarf-version=5")))
+    }
+    try assertNoDriverDiagnostics(args: "swiftc", "foo.swift", "-g", "-c", "-target", "arm64-apple-xros1.0-simulator") { driver in
+      let jobs = try driver.planBuild()
+      XCTAssertTrue(jobs[0].commandLine.contains(.flag("-dwarf-version=4")))
+    }
+    try assertNoDriverDiagnostics(args: "swiftc", "foo.swift", "-g", "-c", "-target", "arm64-apple-xros2.0") { driver in
+      let jobs = try driver.planBuild()
+      XCTAssertTrue(jobs[0].commandLine.contains(.flag("-dwarf-version=5")))
+    }
+
+    try assertNoDriverDiagnostics(args: "swiftc", "foo.swift", "-c", "-file-compilation-dir", ".") { driver in
+      let jobs = try driver.planBuild()
+      XCTAssertFalse(jobs[0].commandLine.contains(.flag("-file-compilation-dir")))
+    }
   }
 
   func testCoverageSettings() throws {