Clean up toolchain-related property names and types, and parameter names and types, and also add comments to document what they are.

Author: abertelrud

Sources/Build/describe().swift

@@ -32,7 +32,7 @@ public func describe(_ prefix: AbsolutePath, _ conf: Configuration, _ graph: Pac
     try makeDirectories(prefix)
     let swiftcArgs = flags.cCompilerFlags.flatMap{ ["-Xcc", $0] } + flags.swiftCompilerFlags + verbosity.ccArgs
 
-    let SWIFT_EXEC = toolchain.SWIFT_EXEC
+    let SWIFT_EXEC = toolchain.swiftCompiler
     let CC = getenv("CC") ?? "clang"
 
     var commands = [Command]()
@@ -41,7 +41,7 @@ public func describe(_ prefix: AbsolutePath, _ conf: Configuration, _ graph: Pac
     for module in graph.modules {
         switch module {
         case let module as SwiftModule:
-            let compile = try Command.compile(swiftModule: module, configuration: conf, prefix: prefix, otherArgs: swiftcArgs + toolchain.platformArgsSwiftc, SWIFT_EXEC: SWIFT_EXEC)
+            let compile = try Command.compile(swiftModule: module, configuration: conf, prefix: prefix, otherArgs: swiftcArgs + toolchain.swiftPlatformArgs, SWIFT_EXEC: SWIFT_EXEC.asString)
             commands.append(compile)
             targets.append([compile], for: module)
 
@@ -51,7 +51,7 @@ public func describe(_ prefix: AbsolutePath, _ conf: Configuration, _ graph: Pac
             if module.isTest { continue }
           #endif
             // FIXME: Find a way to eliminate `externalModules` from here.
-            let compile = try Command.compile(clangModule: module, externalModules: graph.externalModules, configuration: conf, prefix: prefix, CC: CC, otherArgs: flags.cCompilerFlags + toolchain.platformArgsClang)
+            let compile = try Command.compile(clangModule: module, externalModules: graph.externalModules, configuration: conf, prefix: prefix, CC: CC, otherArgs: flags.cCompilerFlags + toolchain.clangPlatformArgs)
             commands += compile
             targets.append(compile, for: module)
 
@@ -76,7 +76,7 @@ public func describe(_ prefix: AbsolutePath, _ conf: Configuration, _ graph: Pac
         if product.containsOnlyClangModules {
             command = try Command.linkClangModule(product, configuration: conf, prefix: prefix, otherArgs: Xld, CC: CC)
         } else {
-            command = try Command.linkSwiftModule(product, configuration: conf, prefix: prefix, otherArgs: Xld + swiftcArgs + toolchain.platformArgsSwiftc + rpathArgs, SWIFT_EXEC: SWIFT_EXEC)
+            command = try Command.linkSwiftModule(product, configuration: conf, prefix: prefix, otherArgs: Xld + swiftcArgs + toolchain.swiftPlatformArgs + rpathArgs, SWIFT_EXEC: SWIFT_EXEC.asString)
         }
 
         commands.append(command)

Sources/Build/misc.swift

@@ -16,11 +16,20 @@ import func POSIX.getenv
 import func POSIX.popen
 
 public protocol Toolchain {
-    var platformArgsClang: [String] { get }
-    var platformArgsSwiftc: [String] { get }
-    var sysroot: String?  { get }
-    var SWIFT_EXEC: String { get }
-    var clang: String { get }
+    /// Path of the `swiftc` compiler.
+    var swiftCompiler: AbsolutePath { get }
+    
+    /// Platform-specific arguments for Swift compiler.
+    var swiftPlatformArgs: [String] { get }
+    
+    /// Path of the `clang` compiler.
+    var clangCompiler: AbsolutePath { get }
+    
+    /// Platform-specific arguments for Clang compiler.
+    var clangPlatformArgs: [String] { get }
+    
+    /// Path of the default SDK (a.k.a. "sysroot"), if any.
+    var defaultSDK: AbsolutePath? { get }
 }
 
 extension AbsolutePath {

Sources/Commands/UserToolchain.swift

@@ -21,28 +21,28 @@ import protocol Build.Toolchain
 #endif
 
 struct UserToolchain: Toolchain {
-    let SWIFT_EXEC: String
-    let clang: String
-    let sysroot: String?
+    /// Path of the `swiftc` compiler.
+    let swiftCompiler: AbsolutePath
+    
+    /// Path of the `clang` compiler.
+    let clangCompiler: AbsolutePath
+    
+    /// Path of the default SDK (a.k.a. "sysroot"), if any.
+    let defaultSDK: AbsolutePath?
 
 #if os(macOS)
-    var platformArgsClang: [String] {
-        return ["-arch", "x86_64", "-mmacosx-version-min=10.10", "-isysroot", sysroot!]
+    var clangPlatformArgs: [String] {
+        return ["-arch", "x86_64", "-mmacosx-version-min=10.10", "-isysroot", defaultSDK!.asString]
     }
-
-    var platformArgsSwiftc: [String] {
-        return ["-target", "x86_64-apple-macosx10.10", "-sdk", sysroot!]
+    var swiftPlatformArgs: [String] {
+        return ["-target", "x86_64-apple-macosx10.10", "-sdk", defaultSDK!.asString]
     }
 #else
-    let platformArgsClang: [String] = []
-    let platformArgsSwiftc: [String] = []
+    let clangPlatformArgs: [String] = []
+    let swiftPlatformArgs: [String] = []
 #endif
 
     init() throws {
-        let swiftCompiler: AbsolutePath
-        let clangCompiler: AbsolutePath
-        let defaultSDK: AbsolutePath?
-        
         // Find the Swift compiler, looking first in the environment.
         if let value = getenv("SWIFT_EXEC"), !value.isEmpty {
             // We have a value, but it could be an absolute or a relative path.
@@ -104,10 +104,5 @@ struct UserToolchain: Toolchain {
       #else
         defaultSDK = nil
       #endif
-        
-        // Finally set the properties (we will refactor these to paths in the next diff).
-        SWIFT_EXEC = swiftCompiler.asString
-        clang = clangCompiler.asString
-        sysroot = defaultSDK?.asString
     }
 }

Tests/BuildTests/DescribeTests.swift

@@ -21,11 +21,11 @@ final class DescribeTests: XCTestCase {
     let dummyPackage = Package(manifest: Manifest(path: AbsolutePath("/"), url: "/", package: PackageDescription.Package(name: "Foo"), products: [], version: nil), path: AbsolutePath("/"), modules: [], testModules: [], products: [])
 
     struct InvalidToolchain: Toolchain {
-        var platformArgsClang: [String] { fatalError() }
-        var platformArgsSwiftc: [String] { fatalError() }
-        var sysroot: String?  { fatalError() }
-        var SWIFT_EXEC: String { fatalError() }
-        var clang: String { fatalError() }
+        var swiftCompiler: AbsolutePath { fatalError() }
+        var clangCompiler: AbsolutePath { fatalError() }
+        var defaultSDK: AbsolutePath?  { fatalError() }
+        var swiftPlatformArgs: [String] { fatalError() }
+        var clangPlatformArgs: [String] { fatalError() }
     }
 
     func testDescribingNoModulesThrows() {