diff --git a/Sources/SwiftDriverExecution/MultiJobExecutor.swift b/Sources/SwiftDriverExecution/MultiJobExecutor.swift
index 8c89c0af6..6afa73f7e 100644
--- a/Sources/SwiftDriverExecution/MultiJobExecutor.swift
+++ b/Sources/SwiftDriverExecution/MultiJobExecutor.swift
@@ -29,6 +29,7 @@ import struct TSCBasic.ProcessResult
 import func TSCBasic.withTemporaryDirectory
 import typealias TSCBasic.ProcessEnvironmentBlock
 import enum TSCUtility.Diagnostics
+import var TSCBasic.stderrStream
 
 // We either import the llbuildSwift shared library or the llbuild framework.
 #if canImport(llbuildSwift)
@@ -579,6 +580,10 @@ class ExecuteJobRule: LLBuildRule {
 
   private func executeJob(_ engine: LLTaskBuildEngine) {
     if context.isBuildCancelled {
+      Driver.stdErrQueue.sync {
+        stderrStream.send("DRIVER EXTRA VERBOSE BUILD WAS CANCELLED\n")
+        stderrStream.flush()
+      }
       engine.taskIsComplete(DriverBuildValue.jobExecution(success: false))
       return
     }
@@ -625,6 +630,12 @@ class ExecuteJobRule: LLBuildRule {
       let success = result.exitStatus == .terminated(code: EXIT_SUCCESS)
 
       if !success {
+        Driver.stdErrQueue.sync {
+          let out = (try? result.utf8Output()) ?? "stdout failed"
+          let err = (try? result.utf8stderrOutput()) ?? "stderr failed"
+          stderrStream.send("DRIVER EXTRA VERBOSE JOB FAILED WITH NON-ZERO \(result.exitStatus) \(job) WITH STDOUT '\(out)' AND STDERR '\(err)'\n")
+          stderrStream.flush()
+        }
         job.removeOutputsOfFailedCompilation(from: context.fileSystem)
         switch result.exitStatus {
         case let .terminated(code):
@@ -672,6 +683,10 @@ class ExecuteJobRule: LLBuildRule {
           context.executorDelegate.jobFinished(job: job, result: result, pid: pid)
         }
       }
+      Driver.stdErrQueue.sync {
+        stderrStream.send("DRIVER EXTRA VERBOSE CAUGHT ERROR IN JOB EXECUTION \(error)\n")
+        stderrStream.flush()
+      }
       value = .jobExecution(success: false)
     }
 
diff --git a/Sources/swift-driver/main.swift b/Sources/swift-driver/main.swift
index d34ee8115..90e6e3557 100644
--- a/Sources/swift-driver/main.swift
+++ b/Sources/swift-driver/main.swift
@@ -155,30 +155,49 @@ do {
   // FIXME: The following check should be at the end of Driver.init, but current
   // usage of the DiagnosticVerifier in tests makes this difficult.
   guard !driver.diagnosticEngine.hasErrors else {
+    printToStderr("DRIVER EXTRA VERBOSE HAD ERRORS")
     throw Driver.ErrorDiagnostics.emitted
   }
 
+  printToStderr("DRIVER EXTRA VERBOSE STARTING PLANNING")
   let jobs = try driver.planBuild()
+  printToStderr("DRIVER EXTRA VERBOSE FINISHED PLANNING")
 
   // Planning may result in further errors emitted
   // due to dependency scanning failures.
   guard !driver.diagnosticEngine.hasErrors else {
+    printToStderr("DRIVER EXTRA VERBOSE HAD ERRORS")
     throw Driver.ErrorDiagnostics.emitted
   }
 
+  printToStderr("DRIVER EXTRA VERBOSE RUNNING JOBS")
   try driver.run(jobs: jobs)
+  printToStderr("DRIVER EXTRA VERBOSE FINISHED JOBS")
 
   if driver.diagnosticEngine.hasErrors {
+    printToStderr("DRIVER EXTRA VERBOSE HAD ERRORS")
     exit(getExitCode(EXIT_FAILURE))
   }
 
+  printToStderr("DRIVER EXTRA VERBOSE SUCCESS")
   exit(getExitCode(0))
 } catch let diagnosticData as DiagnosticData {
+  printToStderr("DRIVER EXTRA VERBOSE IN CATCH FOR DIAGNOSTIC EMISSION")
   diagnosticsEngine.emit(.error(diagnosticData))
   exit(getExitCode(EXIT_FAILURE))
 } catch Driver.ErrorDiagnostics.emitted {
+  printToStderr("DRIVER EXTRA VERBOSE IN CATCH FOR ALREADY EMITTED DIAGNOSTICS")
   exit(getExitCode(EXIT_FAILURE))
 } catch {
-  print("error: \(error)")
+  printToStderr("DRIVER EXTRA VERBOSE IN CATCH FOR OTHER ERROR")
+  printToStderr("error: \(error)")
   exit(getExitCode(EXIT_FAILURE))
 }
+
+import var TSCBasic.stderrStream
+func printToStderr(_ message: String) {
+  Driver.stdErrQueue.sync {
+    stderrStream.send(message + "\n")
+    stderrStream.flush()
+  }
+}