Support required in-place execution of jobs; Require it for the REPL and immediate mode

Author: owenv

Sources/SwiftDriver/Driver/Driver.swift

@@ -575,6 +575,11 @@ extension Driver {
       return
     }
 
+    if jobs.contains(where: { $0.requiresInPlaceExecution }) {
+      assert(jobs.count == 1, "Cannot execute in place for multi-job build plans")
+      return try executeJobInPlace(jobs[0], resolver: resolver)
+    }
+
     // Create and use the tool execution delegate if one is not provided explicitly.
     let executorDelegate = executorDelegate ?? createToolExecutionDelegate()
 
@@ -606,6 +611,19 @@ extension Driver {
 
     return ToolExecutionDelegate(mode: mode)
   }
+
+  /// Execute a single job in-place.
+  private func executeJobInPlace(_ job: Job, resolver: ArgsResolver) throws {
+    let tool = try resolver.resolve(.path(job.tool))
+    let commandLine = try job.commandLine.map{ try resolver.resolve($0) }
+    let arguments = [tool] + commandLine
+
+    for (envVar, value) in job.extraEnvironment {
+      try ProcessEnv.setVar(envVar, value: value)
+    }
+
+    return try exec(path: tool, args: arguments)
+  }
 }
 
 extension Diagnostic.Message {

Sources/SwiftDriver/Jobs/InterpretJob.swift

@@ -46,7 +46,8 @@ extension Driver {
       commandLine: commandLine,
       inputs:inputs,
       outputs: [],
-      extraEnvironment: extraEnvironment
+      extraEnvironment: extraEnvironment,
+      requiresInPlaceExecution: true
     )
   }
 }

Sources/SwiftDriver/Jobs/Job.swift

@@ -50,6 +50,9 @@ public struct Job: Codable, Equatable {
   /// Any extra environment variables which should be set while running the job.
   public var extraEnvironment: [String: String]
 
+  /// Whether or not the job must be executed in place, replacing the current driver process.
+  public var requiresInPlaceExecution: Bool
+
   /// The kind of job.
   public var kind: Kind
 
@@ -60,7 +63,8 @@ public struct Job: Codable, Equatable {
     displayInputs: [TypedVirtualPath]? = nil,
     inputs: [TypedVirtualPath],
     outputs: [TypedVirtualPath],
-    extraEnvironment: [String: String] = [:]
+    extraEnvironment: [String: String] = [:],
+    requiresInPlaceExecution: Bool = false
   ) {
     self.kind = kind
     self.tool = tool
@@ -69,6 +73,7 @@ public struct Job: Codable, Equatable {
     self.inputs = inputs
     self.outputs = outputs
     self.extraEnvironment = extraEnvironment
+    self.requiresInPlaceExecution = requiresInPlaceExecution
   }
 }
 

Sources/SwiftDriver/Jobs/ReplJob.swift

@@ -32,7 +32,8 @@ extension Driver {
         tool: .absolute(try toolchain.getToolPath(.lldb)),
         commandLine: [Job.ArgTemplate.flag(lldbArg)],
         inputs: [],
-        outputs: []
+        outputs: [],
+        requiresInPlaceExecution: true
       )
     } else {
       // Invoke the integrated REPL, which is part of the frontend.
@@ -43,7 +44,8 @@ extension Driver {
         tool: .absolute(try toolchain.getToolPath(.swiftCompiler)),
         commandLine: commandLine,
         inputs: [],
-        outputs: []
+        outputs: [],
+        requiresInPlaceExecution: true
       )
     }
   }

Tests/SwiftDriverTests/SwiftDriverTests.swift

@@ -901,6 +901,7 @@ final class SwiftDriverTests: XCTestCase {
       XCTAssertEqual(plannedJobs.count, 1)
       let replJob = plannedJobs.first!
       XCTAssertTrue(replJob.tool.name.contains("lldb"))
+      XCTAssertTrue(replJob.requiresInPlaceExecution)
       XCTAssert(replJob.commandLine.contains(where: { isLLDBREPLFlag($0) }))
     }
 
@@ -910,6 +911,7 @@ final class SwiftDriverTests: XCTestCase {
       XCTAssertEqual(plannedJobs.count, 1)
       let replJob = plannedJobs.first!
       XCTAssertTrue(replJob.tool.name.contains("lldb"))
+      XCTAssertTrue(replJob.requiresInPlaceExecution)
       XCTAssert(replJob.commandLine.contains(where: { isLLDBREPLFlag($0) }))
     }
 
@@ -921,6 +923,7 @@ final class SwiftDriverTests: XCTestCase {
       XCTAssertEqual(plannedJobs.count, 1)
       let replJob = plannedJobs.first!
       XCTAssertTrue(replJob.tool.name.contains("lldb"))
+      XCTAssertTrue(replJob.requiresInPlaceExecution)
       XCTAssert(replJob.commandLine.contains(where: { isLLDBREPLFlag($0) }))
     }
 
@@ -930,6 +933,7 @@ final class SwiftDriverTests: XCTestCase {
       XCTAssertEqual(plannedJobs.count, 1)
       let replJob = plannedJobs.first!
       XCTAssertTrue(replJob.tool.name.contains("swift"))
+      XCTAssertTrue(replJob.requiresInPlaceExecution)
       XCTAssertTrue(replJob.commandLine.count >= 2)
       XCTAssertEqual(replJob.commandLine[0], .flag("-frontend"))
       XCTAssertEqual(replJob.commandLine[1], .flag("-repl"))
@@ -950,6 +954,7 @@ final class SwiftDriverTests: XCTestCase {
       let plannedJobs = try driver.planBuild()
       XCTAssertEqual(plannedJobs.count, 1)
       let job = plannedJobs[0]
+      XCTAssertTrue(job.requiresInPlaceExecution)
       XCTAssertEqual(job.inputs.count, 1)
       XCTAssertEqual(job.inputs[0].file, .relative(RelativePath("foo.swift")))
       XCTAssertEqual(job.outputs.count, 0)
@@ -967,6 +972,7 @@ final class SwiftDriverTests: XCTestCase {
       let plannedJobs = try driver.planBuild()
       XCTAssertEqual(plannedJobs.count, 1)
       let job = plannedJobs[0]
+      XCTAssertTrue(job.requiresInPlaceExecution)
       XCTAssertEqual(job.inputs.count, 1)
       XCTAssertEqual(job.inputs[0].file, .relative(RelativePath("foo.swift")))
       XCTAssertEqual(job.outputs.count, 0)
@@ -985,6 +991,7 @@ final class SwiftDriverTests: XCTestCase {
       let plannedJobs = try driver.planBuild()
       XCTAssertEqual(plannedJobs.count, 1)
       let job = plannedJobs[0]
+      XCTAssertTrue(job.requiresInPlaceExecution)
       XCTAssertEqual(job.inputs.count, 1)
       XCTAssertEqual(job.inputs[0].file, .relative(RelativePath("foo.swift")))
       XCTAssertEqual(job.outputs.count, 0)