enable static linking of the swift runtime libraries by default on supported platforms

Sources/Build/BuildPlan.swift

@@ -1127,8 +1127,7 @@ public final class SwiftTargetBuildDescription {
     }
 
     private var stdlibArguments: [String] {
-        if buildParameters.shouldLinkStaticSwiftStdlib &&
-            buildParameters.triple.isSupportingStaticStdlib {
+        if buildParameters.shouldStaticallyLinkSwiftRuntimeLibrary {
             return ["-static-stdlib"]
         } else {
             return []
@@ -1304,12 +1303,8 @@ public final class ProductBuildDescription {
             args += deadStripArguments
         case .executable, .snippet:
             // Link the Swift stdlib statically, if requested.
-            if buildParameters.shouldLinkStaticSwiftStdlib {
-                if buildParameters.triple.isDarwin() {
-                    self.observabilityScope.emit(.swiftBackDeployError)
-                } else if buildParameters.triple.isSupportingStaticStdlib {
-                    args += ["-static-stdlib"]
-                }
+            if buildParameters.shouldStaticallyLinkSwiftRuntimeLibrary {
+                args += ["-static-stdlib"]
             }
             args += ["-emit-executable"]
             args += deadStripArguments
@@ -2284,8 +2279,23 @@ private func generateResourceInfoPlist(
     return true
 }
 
-fileprivate extension TSCUtility.Triple {
-    var isSupportingStaticStdlib: Bool {
+extension BuildParameters {
+    fileprivate var shouldStaticallyLinkSwiftRuntimeLibrary: Bool {
+        guard !self.disableAutomaticSwiftRuntimeStaticLinking else {
+            return false
+        }
+        guard self.triple.isSupportingStaticStdlib else {
+            return false
+        }
+        guard self.configuration == .release else {
+            return false
+        }
+        return true
+    }
+}
+
+extension TSCUtility.Triple {
+    fileprivate var isSupportingStaticStdlib: Bool {
         isLinux() || arch == .wasm32
     }
 }

Sources/Commands/Options.swift

@@ -200,7 +200,6 @@ struct ResolverOptions: ParsableArguments {
     @Flag(name: .customLong("skip-update"), help: "Skip updating dependencies from their remote during a resolution")
     var skipDependencyUpdate: Bool = false
 
-
     @Flag(help: "Define automatic transformation of source control based dependencies to registry based ones")
     var sourceControlToRegistryDependencyTransformation: SourceControlToRegistryDependencyTransformation = .disabled
 
@@ -387,9 +386,13 @@ struct LinkerOptions: ParsableArguments {
         help: "Disable/enable dead code stripping by the linker")
     var linkerDeadStrip: Bool = true
 
+    /// If should link the Swift runtime libraries (stdlib, foundation, dispatch, etc) statically.
+    @Flag(name: .customLong("disable-static-swift-runtime"), help: "Disable static linking of the Swift runtime libraries (which is done automatically on supported platforms like Linux)")
+    var disableAutomaticSwiftRuntimeStaticLinking: Bool = false
+
     /// If should link the Swift stdlib statically.
-    @Flag(name: .customLong("static-swift-stdlib"), inversion: .prefixedNo, help: "Link Swift stdlib statically")
-    var shouldLinkStaticSwiftStdlib: Bool = false
+    @Flag(name: .customLong("static-swift-stdlib"), inversion: .prefixedNo, help: .hidden)
+    var _deprecated_shouldLinkStaticSwiftStdlib: Bool?
 }
 
 

Sources/Commands/SwiftTool.swift

@@ -536,6 +536,10 @@ public class SwiftTool {
         if options.caching._deprecated_useRepositoriesCache != nil {
             observabilityScope.emit(warning: "'--disable-repository-cache'/'--enable-repository-cache' flags are deprecated; use '--disable-dependency-cache'/'--enable-dependency-cache' instead")
         }
+
+        if options.linker._deprecated_shouldLinkStaticSwiftStdlib != nil {
+            observabilityScope.emit(warning: "'--shouldLinkStaticSwiftStdlib' option is deprecated; Statically linking the Swift runtime is automatically done on relevant platforms (eg Linux). You may opt out of this behavior with --disable-static-swift-runtime")
+        }
     }
 
     /// Returns the currently active workspace.
@@ -678,7 +682,7 @@ public class SwiftTool {
             throw error
         }
     }
-    
+
     func getPluginScriptRunner(customPluginsDir: AbsolutePath? = .none) throws -> PluginScriptRunner {
         let pluginsDir = try customPluginsDir ?? self.getActiveWorkspace().location.pluginWorkingDirectory
         let cacheDir = pluginsDir.appending(component: "cache")
@@ -819,7 +823,8 @@ public class SwiftTool {
             // can be used to build for any Apple platform and it has it's own
             // conventions for build subpaths based on platforms.
             let dataPath = self.scratchDirectory.appending(
-                component: options.build.buildSystem == .xcode ? "apple" : triple.platformBuildPathComponent())
+                component: options.build.buildSystem == .xcode ? "apple" : triple.platformBuildPathComponent()
+            )
             return BuildParameters(
                 dataPath: dataPath,
                 configuration: options.build.configuration,
@@ -829,7 +834,7 @@ public class SwiftTool {
                 flags: options.build.buildFlags,
                 xcbuildFlags: options.build.xcbuildFlags,
                 jobs: options.build.jobs ?? UInt32(ProcessInfo.processInfo.activeProcessorCount),
-                shouldLinkStaticSwiftStdlib: options.linker.shouldLinkStaticSwiftStdlib,
+                disableAutomaticSwiftRuntimeStaticLinking: options.linker.disableAutomaticSwiftRuntimeStaticLinking,
                 canRenameEntrypointFunctionName: SwiftTargetBuildDescription.checkSupportedFrontendFlags(
                     flags: ["entry-point-function-name"], fileSystem: self.fileSystem
                 ),

Sources/SPMBuildCore/BuildParameters.swift

@@ -97,8 +97,8 @@ public struct BuildParameters: Encodable {
     /// How many jobs should llbuild and the Swift compiler spawn
     public var jobs: UInt32
 
-    /// If should link the Swift stdlib statically.
-    public var shouldLinkStaticSwiftStdlib: Bool
+    /// Disable automatic statically link the Swift runtime on supported platforms.
+    public var disableAutomaticSwiftRuntimeStaticLinking: Bool
 
     /// Which compiler sanitizers should be enabled
     public var sanitizers: EnabledSanitizers
@@ -188,7 +188,7 @@ public struct BuildParameters: Encodable {
         flags: BuildFlags,
         xcbuildFlags: [String] = [],
         jobs: UInt32 = UInt32(ProcessInfo.processInfo.activeProcessorCount),
-        shouldLinkStaticSwiftStdlib: Bool = false,
+        disableAutomaticSwiftRuntimeStaticLinking: Bool = false,
         shouldEnableManifestCaching: Bool = false,
         canRenameEntrypointFunctionName: Bool = false,
         shouldCreateDylibForDynamicProducts: Bool = true,
@@ -218,7 +218,7 @@ public struct BuildParameters: Encodable {
         self.flags = flags
         self.xcbuildFlags = xcbuildFlags
         self.jobs = jobs
-        self.shouldLinkStaticSwiftStdlib = shouldLinkStaticSwiftStdlib
+        self.disableAutomaticSwiftRuntimeStaticLinking = disableAutomaticSwiftRuntimeStaticLinking
         self.shouldEnableManifestCaching = shouldEnableManifestCaching
         self.shouldCreateDylibForDynamicProducts = shouldCreateDylibForDynamicProducts
         self.canRenameEntrypointFunctionName = canRenameEntrypointFunctionName