Add -Xswiftc for passing args to swiftc

Like our -Xcc and -Xlinker flags, -Xswiftc is only allowed on the command line and not part of Package.swift in an effort to prevent CMake/Autotools like developer hells.

Strictly we add these flags so developers can work around issues, but they also should report a bug so that we can provide a proper solution for their needs.

Sources/Build/describe().swift

@@ -16,7 +16,7 @@ import Utility
 /**
   - Returns: path to generated YAML for consumption by the llbuild based swift-build-tool
 */
-public func describe(prefix: String, _ conf: Configuration, _ modules: [Module], _ products: [Product], Xcc: [String], Xld: [String]) throws -> String {
+public func describe(prefix: String, _ conf: Configuration, _ modules: [Module], _ products: [Product], Xcc: [String], Xld: [String], Xswiftc: [String]) throws -> String {
 
     guard modules.count > 0 else {
         fatalError("No modules input")  //TODO throw
@@ -41,9 +41,12 @@ public func describe(prefix: String, _ conf: Configuration, _ modules: [Module],
 
     var mkdirs = Set<String>()
 
+
+    let swiftcArgs = Xcc + Xswiftc
+
     for case let module as SwiftModule in modules {
 
-        let otherArgs = Xcc + module.Xcc + platformArgs() + [conf.define]
+        let otherArgs = swiftcArgs + module.Xcc + platformArgs() + [conf.define]
 
         switch conf {
         case .Debug:
@@ -83,7 +86,7 @@ public func describe(prefix: String, _ conf: Configuration, _ modules: [Module],
 
         case .Release:
             let inputs = module.dependencies.map{ $0.targetName } + module.sources.paths
-            var args = ["-c", "-emit-module", "-D", "SWIFT_PACKAGE", "-O", "-whole-module-optimization", "-I", prefix]
+            var args = ["-c", "-emit-module", "-D", "SWIFT_PACKAGE", "-O", "-whole-module-optimization", "-I", prefix] + swiftcArgs
             let productPath = Path.join(prefix, "\(module.c99name).o")
 
             if module.isLibrary {
@@ -117,7 +120,7 @@ public func describe(prefix: String, _ conf: Configuration, _ modules: [Module],
             objects = product.buildables.flatMap{ return IncrementalNode(module: $0, prefix: prefix).objectPaths }
         }
 
-        var args = [Resources.path.swiftc]
+        var args = [Resources.path.swiftc] + swiftcArgs
 
         switch product.type {
         case .Library(.Static):
@@ -145,7 +148,6 @@ public func describe(prefix: String, _ conf: Configuration, _ modules: [Module],
                 let hack2 = hack1.sources.root.parentDirectory
                 let hack3 = Path.join(hack2, "LinuxMain.swift")
                 args.append(hack3)
-                args += Xcc
 
                 args.append("-emit-executable")
                 args += ["-I", prefix]

Sources/swift-build/main.swift

@@ -45,7 +45,7 @@ do {
             let dirs = try directories()
             let packages = try fetch(dirs.root)
             let (modules, products) = try transmute(packages)
-            let yaml = try describe(dirs.build, conf, modules, products, Xcc: opts.Xcc, Xld: opts.Xlinker)
+            let yaml = try describe(dirs.build, conf, modules, products, Xcc: opts.Xcc, Xld: opts.Xld, Xswiftc: opts.Xswiftc)
             try build(YAMLPath: yaml, target: "default")
 
         case .Init:

Sources/swift-build/usage.swift

@@ -12,27 +12,23 @@ import enum Build.Configuration
 import Multitool
 
 func usage(print: (String) -> Void = { print($0) }) {
-    //.........10.........20.........30.........40.........50.........60.........70..
+         //.........10.........20.........30.........40.........50.........60.........70..
     print("OVERVIEW: Build sources into binary products")
     print("")
     print("USAGE: swift build [options]")
     print("")
     print("MODES:")
     print("  --configuration <value>  Build with configuration (debug|release) [-c]")
-    print("  --clean[=<mode>]         Delete all build intermediaries and products [-k]")
-    print("                           <mode> is one of:")
-    print("                           build - Build intermediaries and products")
-    print("                           dist  - All of 'build' plus downloaded packages")
-    print("                           If no mode is given, 'build' is the default.")
+    print("  --clean[=<mode>]         Delete artefacts (build|dist) [-k]")
     print("  --init                   Creates a new Swift project")
     print("  --fetch                  Fetch package dependencies")
     print("")
     print("OPTIONS:")
     print("  --chdir <value>    Change working directory before any other operation [-C]")
     print("  -v[v]              Increase verbosity of informational output")
-    print("  -Xcc <flag>        Pass flag through to all compiler instantiations")
+    print("  -Xcc <flag>        Pass flag through to all C compiler instantiations")
     print("  -Xlinker <flag>    Pass flag through to all linker instantiations")
-    print("  --get             Only pull down dependencies without building binaries")
+    print("  -Xswiftc <flag>    Pass flag through to all Swift compiler instantiations")
 }
 
 enum CleanMode: String {
@@ -53,7 +49,8 @@ struct Options {
     var chdir: String? = nil
     var verbosity: Int = 0
     var Xcc: [String] = []
-    var Xlinker: [String] = []
+    var Xld: [String] = []
+    var Xswiftc: [String] = []
 }
 
 func parse(commandLineArguments args: [String]) throws -> (Mode, Options) {
@@ -69,7 +66,7 @@ func parse(commandLineArguments args: [String]) throws -> (Mode, Options) {
             return [arg]
         }
 
-        if arg == "-Xcc" || arg == "-Xlinker" {
+        if "-Xcc" == arg || "-Xlinker" == arg || "-Xswiftc" == arg {
             skipNext = true
             return [arg]
         }
@@ -158,7 +155,10 @@ func parse(commandLineArguments args: [String]) throws -> (Mode, Options) {
             opts.Xcc.append(try cruncher.rawPop())
 
         case .Switch(.Xlinker):
-            opts.Xlinker.append(try cruncher.rawPop())
+            opts.Xld.append(try cruncher.rawPop())
+
+        case .Switch(.Xswiftc):
+            opts.Xswiftc.append(try cruncher.rawPop())
         }
     }
 
@@ -219,6 +219,7 @@ private struct Cruncher {
             case Verbose = "--verbose"
             case Xcc = "-Xcc"
             case Xlinker = "-Xlinker"
+            case Xswiftc = "-Xswiftc"
 
             init?(rawValue: String) {
                 switch rawValue {
@@ -230,6 +231,8 @@ private struct Cruncher {
                     self = .Xcc
                 case Xlinker.rawValue:
                     self = .Xlinker
+                case Xswiftc.rawValue:
+                    self = .Xswiftc
                 default:
                     return nil
                 }

Sources/swift-build/xp.swift

@@ -14,9 +14,9 @@ import Build
 import POSIX
 
 #if os(Linux)
-public func describe(prefix: String, _ conf: Configuration, _ modules: [Module], _ products: [Product], Xcc: [String], Xld: [String]) throws -> String {
+public func describe(prefix: String, _ conf: Configuration, _ modules: [Module], _ products: [Product], Xcc: [String], Xld: [String], Xswiftc: [String]) throws -> String {
     do {
-        return try Build.describe(prefix, conf, modules, products, Xcc: Xcc, Xld: Xld)
+        return try Build.describe(prefix, conf, modules, products, Xcc: Xcc, Xld: Xld, Xswftc: Xswiftc)
     } catch {
 
         // it is a common error on Linux for clang++ to not be installed, but