[5.1] Don't link runtime compatibility library in pure Clang targets.

Sources/Build/BuildPlan.swift

@@ -701,11 +701,13 @@ public final class ProductBuildDescription {
         args += ["-module-name", product.name.spm_mangledToC99ExtendedIdentifier()]
         args += dylibs.map({ "-l" + $0.product.name })
 
-        // Add arguements needed for code coverage if it is enabled.
+        // Add arguments needed for code coverage if it is enabled.
         if buildParameters.enableCodeCoverage {
             args += ["-profile-coverage-mapping", "-profile-generate"]
         }
 
+        let containsSwiftTargets = product.containsSwiftTargets
+
         switch product.type {
         case .library(.automatic):
             fatalError()
@@ -725,7 +727,8 @@ public final class ProductBuildDescription {
             // Link the Swift stdlib statically, if requested.
             //
             // FIXME: This does not work for linux yet (SR-648).
-            if buildParameters.shouldLinkStaticSwiftStdlib {
+            if containsSwiftTargets,
+               buildParameters.shouldLinkStaticSwiftStdlib {
                 if buildParameters.triple.isDarwin() {
                     diagnostics.emit(data: SwiftBackDeployLibrariesNote())
                 }
@@ -741,16 +744,24 @@ public final class ProductBuildDescription {
         args += ["@\(linkFileListPath.pathString)"]
 
         // Embed the swift stdlib library path inside tests and executables on Darwin.
-        switch product.type {
-        case .library: break
-        case .test, .executable:
-            if buildParameters.triple.isDarwin() {
-                let stdlib = buildParameters.toolchain.macosSwiftStdlib
-                args += ["-Xlinker", "-rpath", "-Xlinker", stdlib.pathString]
-            }
+        if containsSwiftTargets {
+          switch product.type {
+          case .library: break
+          case .test, .executable:
+              if buildParameters.triple.isDarwin() {
+                  let stdlib = buildParameters.toolchain.macosSwiftStdlib
+                  args += ["-Xlinker", "-rpath", "-Xlinker", stdlib.pathString]
+              }
+          }
         }
 
-        // Add agruments from declared build settings.
+        // Don't link runtime compatibility patch libraries if there are no
+        // Swift sources in the target.
+        if !containsSwiftTargets {
+          args += ["-runtime-compatibility-version", "none"]
+        }
+
+        // Add arguments from declared build settings.
         args += self.buildSettingsFlags()
 
         // User arguments (from -Xlinker and -Xswiftc) should follow generated arguments to allow user overrides

Sources/PackageModel/ResolvedModels.swift

@@ -178,6 +178,18 @@ public final class ResolvedProduct: ObjectIdentifierProtocol, CustomStringConver
     public var description: String {
         return "<ResolvedProduct: \(name)>"
     }
+
+    /// True if this product contains Swift targets.
+    public var containsSwiftTargets: Bool {
+      //  C targets can't import Swift targets in SwiftPM (at least not right
+      // now), so we can just look at the top-level targets.
+      //
+      // If that ever changes, we'll need to do something more complex here,
+      // recursively checking dependencies for SwiftTargets, and considering
+      // dynamic library targets to be Swift targets (since the dylib could
+      // contain Swift code we don't know about as part of this build).
+      return targets.contains { $0.underlyingTarget is SwiftTarget }
+    }
 }
 
 extension ResolvedTarget.Dependency: CustomStringConvertible {

Tests/BuildTests/BuildPlanTests.swift

@@ -318,14 +318,15 @@ final class BuildPlanTests: XCTestCase {
             "/fake/path/to/swiftc", "-g", "-L", "/path/to/build/debug",
             "-o", "/path/to/build/debug/exe", "-module-name", "exe", "-emit-executable",
             "@/path/to/build/debug/exe.product/Objects.LinkFileList",
-            "-Xlinker", "-rpath", "-Xlinker", "/fake/path/lib/swift/macosx",
+            "-runtime-compatibility-version", "none",
         ])
       #else
         XCTAssertEqual(try result.buildProduct(for: "exe").linkArguments(), [
             "/fake/path/to/swiftc", "-g", "-L", "/path/to/build/debug",
             "-o", "/path/to/build/debug/exe", "-module-name", "exe", "-emit-executable",
             "-Xlinker", "-rpath=$ORIGIN",
             "@/path/to/build/debug/exe.product/Objects.LinkFileList",
+            "-runtime-compatibility-version", "none",
         ])
       #endif
 
@@ -374,14 +375,15 @@ final class BuildPlanTests: XCTestCase {
             "/fake/path/to/swiftc", "-lc++", "-g", "-L", "/path/to/build/debug", "-o",
             "/path/to/build/debug/exe", "-module-name", "exe", "-emit-executable",
             "@/path/to/build/debug/exe.product/Objects.LinkFileList",
-            "-Xlinker", "-rpath", "-Xlinker", "/fake/path/lib/swift/macosx",
+            "-runtime-compatibility-version", "none",
         ])
       #else
         XCTAssertEqual(try result.buildProduct(for: "exe").linkArguments(), [
             "/fake/path/to/swiftc", "-lstdc++", "-g", "-L", "/path/to/build/debug", "-o",
             "/path/to/build/debug/exe", "-module-name", "exe", "-emit-executable",
             "-Xlinker", "-rpath=$ORIGIN",
             "@/path/to/build/debug/exe.product/Objects.LinkFileList",
+            "-runtime-compatibility-version", "none",
         ])
       #endif
 
@@ -865,12 +867,12 @@ final class BuildPlanTests: XCTestCase {
         XCTAssertEqual(lib.moduleMap, AbsolutePath("/path/to/build/debug/lib.build/module.modulemap"))
 
     #if os(macOS)
-        XCTAssertEqual(try result.buildProduct(for: "lib").linkArguments(), ["/fake/path/to/swiftc", "-lc++", "-g", "-L", "/path/to/build/debug", "-o", "/path/to/build/debug/liblib.dylib", "-module-name", "lib", "-emit-library", "@/path/to/build/debug/lib.product/Objects.LinkFileList"])
+        XCTAssertEqual(try result.buildProduct(for: "lib").linkArguments(), ["/fake/path/to/swiftc", "-lc++", "-g", "-L", "/path/to/build/debug", "-o", "/path/to/build/debug/liblib.dylib", "-module-name", "lib", "-emit-library", "@/path/to/build/debug/lib.product/Objects.LinkFileList", "-runtime-compatibility-version", "none"])
 
-        XCTAssertEqual(try result.buildProduct(for: "exe").linkArguments(), ["/fake/path/to/swiftc", "-g", "-L", "/path/to/build/debug", "-o", "/path/to/build/debug/exe", "-module-name", "exe", "-emit-executable", "@/path/to/build/debug/exe.product/Objects.LinkFileList", "-Xlinker", "-rpath", "-Xlinker", "/fake/path/lib/swift/macosx",])
+        XCTAssertEqual(try result.buildProduct(for: "exe").linkArguments(), ["/fake/path/to/swiftc", "-g", "-L", "/path/to/build/debug", "-o", "/path/to/build/debug/exe", "-module-name", "exe", "-emit-executable", "@/path/to/build/debug/exe.product/Objects.LinkFileList", "-runtime-compatibility-version", "none"])
     #else
-        XCTAssertEqual(try result.buildProduct(for: "lib").linkArguments(), ["/fake/path/to/swiftc", "-lstdc++", "-g", "-L", "/path/to/build/debug", "-o", "/path/to/build/debug/liblib.so", "-module-name", "lib", "-emit-library", "-Xlinker", "-rpath=$ORIGIN", "@/path/to/build/debug/lib.product/Objects.LinkFileList"])
-        XCTAssertEqual(try result.buildProduct(for: "exe").linkArguments(), ["/fake/path/to/swiftc", "-g", "-L", "/path/to/build/debug", "-o", "/path/to/build/debug/exe", "-module-name", "exe", "-emit-executable", "-Xlinker", "-rpath=$ORIGIN", "@/path/to/build/debug/exe.product/Objects.LinkFileList"])
+        XCTAssertEqual(try result.buildProduct(for: "lib").linkArguments(), ["/fake/path/to/swiftc", "-lstdc++", "-g", "-L", "/path/to/build/debug", "-o", "/path/to/build/debug/liblib.so", "-module-name", "lib", "-emit-library", "-Xlinker", "-rpath=$ORIGIN", "@/path/to/build/debug/lib.product/Objects.LinkFileList", "-runtime-compatibility-version", "none"])
+        XCTAssertEqual(try result.buildProduct(for: "exe").linkArguments(), ["/fake/path/to/swiftc", "-g", "-L", "/path/to/build/debug", "-o", "/path/to/build/debug/exe", "-module-name", "exe", "-emit-executable", "-Xlinker", "-rpath=$ORIGIN", "@/path/to/build/debug/exe.product/Objects.LinkFileList", "-runtime-compatibility-version", "none"])
     #endif
     }
 

Tests/FunctionalTests/CFamilyTargetTests.swift

@@ -75,7 +75,6 @@ class CFamilyTargetTestCase: XCTestCase {
     }
 
     func testObjectiveCPackageWithTestTarget(){
-      #if DISABLED // rdar://problem/50057445
       #if os(macOS)
         fixture(name: "CFamilyTargets/ObjCmacOSPackage") { prefix in
             // Build the package.
@@ -85,6 +84,5 @@ class CFamilyTargetTestCase: XCTestCase {
             XCTAssertSwiftTest(prefix)
         }
       #endif
-      #endif
     }
 }

Tests/FunctionalTests/MiscellaneousTests.swift

@@ -272,7 +272,6 @@ class MiscellaneousTestCase: XCTestCase {
     }
 
     func testPkgConfigCFamilyTargets() throws {
-    #if DISABLED // rdar://problem/50057445
         fixture(name: "Miscellaneous/PkgConfig") { prefix in
             let systemModule = prefix.appending(component: "SystemModule")
             // Create a shared library.
@@ -304,7 +303,6 @@ class MiscellaneousTestCase: XCTestCase {
 
             XCTAssertFileExists(moduleUser.appending(components: ".build", Destination.host.target.tripleString, "debug", "SystemModuleUserClang"))
         }
-    #endif
     }
 
     func testCanKillSubprocessOnSigInt() throws {