Extract build planning from Driver.run

Author: owenv

Sources/SwiftDriver/Driver/Driver.swift

@@ -551,37 +551,9 @@ extension Driver {
     }
   }
 
-  /// Create a job if needed for simple requests that can be immediately
-  /// forwarded to the frontend.
-  public mutating func immediateForwardingJob() throws -> Job? {
-    if parsedOptions.hasArgument(.printTargetInfo) {
-      var commandLine: [Job.ArgTemplate] = [.flag("-frontend"),
-                                            .flag("-print-target-info")]
-      try commandLine.appendLast(.target, from: &parsedOptions)
-      try commandLine.appendLast(.sdk, from: &parsedOptions)
-      try commandLine.appendLast(.resourceDir, from: &parsedOptions)
-      return Job(kind: .printTargetInfo,
-                 tool: .absolute(try toolchain.getToolPath(.swiftCompiler)),
-                 commandLine: commandLine,
-                 inputs: [],
-                 outputs: [],
-                 requiresInPlaceExecution: true)
-    }
-
-    if parsedOptions.hasArgument(.version) || parsedOptions.hasArgument(.version_) {
-      return Job(kind: .versionRequest,
-                 tool: .absolute(try toolchain.getToolPath(.swiftCompiler)),
-                 commandLine: [.flag("--version")],
-                 inputs: [],
-                 outputs: [],
-                 requiresInPlaceExecution: true)
-    }
-
-    return nil
-  }
-
   /// Run the driver.
   public mutating func run(
+    jobs: [Job],
     resolver: ArgsResolver,
     executorDelegate: JobExecutorDelegate? = nil,
     processSet: ProcessSet? = nil
@@ -600,14 +572,6 @@ extension Driver {
       try printVersion(outputStream: &stderrStream)
     }
 
-    let jobs: [Job]
-    if let job = try immediateForwardingJob() {
-      jobs = [job]
-    } else {
-      // Plan the build.
-      jobs = try planBuild()
-    }
-
     if jobs.isEmpty { return }
 
     // If we're only supposed to print the jobs, do so now.

Sources/SwiftDriver/Jobs/Planning.swift

@@ -165,8 +165,42 @@ extension Driver {
     return jobs
   }
 
+  /// Create a job if needed for simple requests that can be immediately
+  /// forwarded to the frontend.
+  public mutating func immediateForwardingJob() throws -> Job? {
+    if parsedOptions.hasArgument(.printTargetInfo) {
+      var commandLine: [Job.ArgTemplate] = [.flag("-frontend"),
+                                            .flag("-print-target-info")]
+      try commandLine.appendLast(.target, from: &parsedOptions)
+      try commandLine.appendLast(.sdk, from: &parsedOptions)
+      try commandLine.appendLast(.resourceDir, from: &parsedOptions)
+      return Job(kind: .printTargetInfo,
+                 tool: .absolute(try toolchain.getToolPath(.swiftCompiler)),
+                 commandLine: commandLine,
+                 inputs: [],
+                 outputs: [],
+                 requiresInPlaceExecution: true)
+    }
+
+    if parsedOptions.hasArgument(.version) || parsedOptions.hasArgument(.version_) {
+      return Job(kind: .versionRequest,
+                 tool: .absolute(try toolchain.getToolPath(.swiftCompiler)),
+                 commandLine: [.flag("--version")],
+                 inputs: [],
+                 outputs: [],
+                 requiresInPlaceExecution: true)
+    }
+
+    return nil
+  }
+
   /// Plan a build by producing a set of jobs to complete the build.
   public mutating func planBuild() throws -> [Job] {
+    // Handle invocations which can be trivially forwarded to the frontend.
+    if let job = try immediateForwardingJob() {
+      return [job]
+    }
+
     // Plan the build.
     switch compilerMode {
     case .repl:

Sources/swift-driver/main.swift

@@ -41,8 +41,9 @@ do {
   }
 
   var driver = try Driver(args: arguments, diagnosticsEngine: diagnosticsEngine)
+  let jobs = try driver.planBuild()
   let resolver = try ArgsResolver()
-  try driver.run(resolver: resolver, processSet: processSet)
+  try driver.run(jobs: jobs, resolver: resolver, processSet: processSet)
 
   if driver.diagnosticEngine.hasErrors {
     exit(EXIT_FAILURE)