Attempt to recover from in-process TargetInfo query failures.

Catch thrown exceptions and fallback to the previous mechanism of shelling out a `swift-frontend -print-target-info` task.
We are seeing spurious failures here and this will help potential users while we investigate the root cause.

Workaround for rdar://105559904

Author: artemcm

Sources/SwiftDriver/Driver/Driver.swift

@@ -2924,6 +2924,7 @@ extension Driver {
                                       swiftCompilerPrefixArgs: frontendOverride.prefixArgsForTargetInfo,
                                       toolchain: toolchain, fileSystem: fileSystem,
                                       workingDirectory: workingDirectory,
+                                      diagnosticsEngine: diagnosticsEngine,
                                       executor: executor).target.triple
   }
 
@@ -2988,6 +2989,7 @@ extension Driver {
                                    swiftCompilerPrefixArgs: frontendOverride.prefixArgsForTargetInfo,
                                    toolchain: toolchain, fileSystem: fileSystem,
                                    workingDirectory: workingDirectory,
+                                   diagnosticsEngine: diagnosticsEngine,
                                    executor: executor)
 
       // Parse the runtime compatibility version. If present, it will override

Sources/SwiftDriver/Jobs/PrintTargetInfoJob.swift

@@ -13,6 +13,7 @@
 import protocol TSCBasic.FileSystem
 import class Foundation.JSONDecoder
 import struct TSCBasic.AbsolutePath
+import class TSCBasic.DiagnosticsEngine
 
 /// Swift versions are major.minor.
 struct SwiftVersion {
@@ -232,6 +233,7 @@ extension Driver {
                                 toolchain: Toolchain,
                                 fileSystem: FileSystem,
                                 workingDirectory: AbsolutePath?,
+                                diagnosticsEngine: DiagnosticsEngine,
                                 executor: DriverExecutor) throws -> FrontendTargetInfo {
     let frontendTargetInfoJob =
       try toolchain.printTargetInfoJob(target: target, targetVariant: targetVariant,
@@ -244,11 +246,16 @@ extension Driver {
                                               useResponseFiles: .disabled,
                                               using: executor.resolver)
     Self.sanitizeCommandForLibScanInvocation(&command)
-    if let targetInfo =
-        try Self.queryTargetInfoInProcess(of: toolchain, fileSystem: fileSystem,
-                                          workingDirectory: workingDirectory,
-                                          invocationCommand: command) {
-      return targetInfo
+
+    do {
+      if let targetInfo =
+          try Self.queryTargetInfoInProcess(of: toolchain, fileSystem: fileSystem,
+                                            workingDirectory: workingDirectory,
+                                            invocationCommand: command) {
+        return targetInfo
+      }
+    } catch {
+      diagnosticsEngine.emit(.warning_inprocess_target_info_query_failed(error.localizedDescription))
     }
 
     // Fallback: Invoke `swift-frontend -print-target-info` and decode the output

Sources/SwiftDriver/Utilities/Diagnostics.swift

@@ -51,6 +51,10 @@ extension Diagnostic.Message {
     .warning("inferring simulator environment for target '\(originalTriple.triple)'; use '-target \(inferredTriple.triple)' instead")
   }
 
+  static func warning_inprocess_target_info_query_failed(_ error: String) -> Diagnostic.Message {
+    .warning("In-process target-info query failed (\(error)). Using fallback mechanism.")
+  }
+
   static func error_argument_not_allowed_with(arg: String, other: String) -> Diagnostic.Message {
     .error("argument '\(arg)' is not allowed with '\(other)'")
   }