Adopt the usage of in-process '-print-target-info' libSwiftScan API on the main compilation code-path

Author: artemcm

Sources/SwiftDriver/Driver/Driver.swift

@@ -2903,13 +2903,10 @@ extension Driver {
     let frontendOverride = try FrontendOverride(&parsedOptions, diagnosticsEngine)
     frontendOverride.setUpForTargetInfo(toolchain)
     defer { frontendOverride.setUpForCompilation(toolchain) }
-    return try executor.execute(
-      job: toolchain.printTargetInfoJob(target: nil, targetVariant: nil,
-                                        swiftCompilerPrefixArgs:
-                                          frontendOverride.prefixArgsForTargetInfo),
-      capturingJSONOutputAs: FrontendTargetInfo.self,
-      forceResponseFiles: false,
-      recordedInputModificationDates: [:]).target.triple
+    return try Self.computeTargetInfo(target: nil, targetVariant: nil,
+                                      swiftCompilerPrefixArgs: frontendOverride.prefixArgsForTargetInfo,
+                                      toolchain: toolchain, fileSystem: fileSystem,
+                                      executor: executor).target.triple
   }
 
   static func computeToolchain(
@@ -2963,18 +2960,16 @@ extension Driver {
 
     // Query the frontend for target information.
     do {
-      var info: FrontendTargetInfo = try executor.execute(
-        job: toolchain.printTargetInfoJob(
-          target: explicitTarget, targetVariant: explicitTargetVariant,
-          sdkPath: sdkPath, resourceDirPath: resourceDirPath,
-          runtimeCompatibilityVersion:
-            parsedOptions.getLastArgument(.runtimeCompatibilityVersion)?.asSingle,
-          useStaticResourceDir: useStaticResourceDir,
-          swiftCompilerPrefixArgs: frontendOverride.prefixArgsForTargetInfo
-        ),
-        capturingJSONOutputAs: FrontendTargetInfo.self,
-        forceResponseFiles: false,
-        recordedInputModificationDates: [:])
+      var info: FrontendTargetInfo =
+        try Self.computeTargetInfo(target: explicitTarget, targetVariant: explicitTargetVariant,
+                                   sdkPath: sdkPath, resourceDirPath: resourceDirPath,
+                                   runtimeCompatibilityVersion:
+                                     parsedOptions.getLastArgument(.runtimeCompatibilityVersion)?.asSingle,
+                                   useStaticResourceDir: useStaticResourceDir,
+                                   swiftCompilerPrefixArgs: frontendOverride.prefixArgsForTargetInfo,
+                                   toolchain: toolchain, fileSystem: fileSystem,
+                                   executor: executor)
+
 
       // Parse the runtime compatibility version. If present, it will override
       // what is reported by the frontend.

Sources/SwiftDriver/Execution/DriverExecutor.swift

@@ -87,6 +87,7 @@ extension DriverExecutor {
                              capturingJSONOutputAs outputType: T.Type,
                              forceResponseFiles: Bool,
                              recordedInputModificationDates: [TypedVirtualPath: TimePoint]) throws -> T {
+    //print(">>> EXEC: \(try self.description(of: job, forceResponseFiles: false))")
     let result = try execute(job: job,
                              forceResponseFiles: forceResponseFiles,
                              recordedInputModificationDates: recordedInputModificationDates)

Sources/SwiftDriver/Jobs/PrintTargetInfoJob.swift

@@ -185,10 +185,30 @@ extension Driver {
     if let swiftScanLibPath = optionalSwiftScanLibPath,
        fileSystem.exists(swiftScanLibPath) {
       let libSwiftScanInstance = try SwiftScan(dylib: swiftScanLibPath)
-      if libSwiftScanInstance.canQueryTargetInfo(),
-         libSwiftScanInstance.supportsStringDispose() {
+      if libSwiftScanInstance.canQueryTargetInfo() {
         let targetInfoData = try libSwiftScanInstance.queryTargetInfoJSON(invocationCommand: invocationCommand)
-        return try JSONDecoder().decode(FrontendTargetInfo.self, from: targetInfoData)
+        do {
+          return try JSONDecoder().decode(FrontendTargetInfo.self, from: targetInfoData)
+        } catch let decodingError as DecodingError {
+          let stringToDecode = String(data: targetInfoData, encoding: .utf8)
+          let errorDesc: String
+          switch decodingError {
+            case let .typeMismatch(type, context):
+              errorDesc = "type mismatch: \(type), path: \(context.codingPath)"
+            case let .valueNotFound(type, context):
+              errorDesc = "value missing: \(type), path: \(context.codingPath)"
+            case let .keyNotFound(key, context):
+              errorDesc = "key missing: \(key), path: \(context.codingPath)"
+           case let .dataCorrupted(context):
+              errorDesc = "data corrupted at path: \(context.codingPath)"
+            @unknown default:
+              errorDesc = "unknown decoding error"
+          }
+          throw Error.unableToDecodeFrontendTargetInfo(
+            stringToDecode,
+            invocationCommand,
+            errorDesc)
+        }
       }
     }
     return nil

Sources/SwiftDriver/SwiftScan/SwiftScan.swift

@@ -333,8 +333,10 @@ internal extension swiftscan_diagnostic_severity_t {
                                              invocationStringArray)
     }
     let targetInfoStringRef = api.swiftscan_compiler_target_info_query(invocation)
-    defer { api.swiftscan_string_dispose(targetInfoStringRef) }
     let targetInfoString = try toSwiftString(targetInfoStringRef)
+    if supportsStringDispose() {
+      api.swiftscan_string_dispose(targetInfoStringRef)
+    }
     let targetInfoData = Data(targetInfoString.utf8)
     return targetInfoData
   }

Tests/SwiftDriverTests/SwiftDriverTests.swift

@@ -4770,7 +4770,7 @@ final class SwiftDriverTests: XCTestCase {
 
   func testPrintTargetInfo() throws {
     do {
-      var driver = try Driver(args: ["swift", "-print-target-info", "-sdk", "bar", "-resource-dir", "baz"])
+      var driver = try Driver(args: ["swift", "-print-target-info", "-target", "arm64-apple-ios12.0", "-sdk", "bar", "-resource-dir", "baz"])
       let plannedJobs = try driver.planBuild()
       XCTAssertTrue(plannedJobs.count == 1)
       let job = plannedJobs[0]
@@ -4781,18 +4781,6 @@ final class SwiftDriverTests: XCTestCase {
       XCTAssertTrue(job.commandLine.contains(.flag("-resource-dir")))
     }
 
-    do {
-      let targetInfoArgs = ["-print-target-info", "-sdk", "bar", "-resource-dir", "baz"]
-      let driver = try Driver(args: ["swift"] + targetInfoArgs)
-      let swiftScanLibPath = try XCTUnwrap(driver.toolchain.lookupSwiftScanLib())
-      if localFileSystem.exists(swiftScanLibPath) {
-        let libSwiftScanInstance = try SwiftScan(dylib: swiftScanLibPath)
-        if libSwiftScanInstance.canQueryTargetInfo() {
-          XCTAssertTrue(try driver.verifyBeingAbleToQueryTargetInfoInProcess(invocationCommand: targetInfoArgs))
-        }
-      }
-    }
-
     do {
       struct MockExecutor: DriverExecutor {
         let resolver: ArgsResolver
@@ -4815,7 +4803,11 @@ final class SwiftDriverTests: XCTestCase {
         }
       }
 
+      // Override path to libSwiftScan to force the fallback of using the executor
+      var hideSwiftScanEnv = ProcessEnv.vars
+      hideSwiftScanEnv["SWIFT_DRIVER_SWIFTSCAN_LIB"] = "/bad/path/lib_InternalSwiftScan.dylib"
       XCTAssertThrowsError(try Driver(args: ["swift", "-print-target-info"],
+                                      env: hideSwiftScanEnv,
                                       executor: MockExecutor(resolver: ArgsResolver(fileSystem: InMemoryFileSystem())))) {
         error in
         if case .unableToDecodeFrontendTargetInfo = error as? Driver.Error {}