[Dependency Scanning] Deprecate/Remove batch scanning capability

Batch dependency scanning was added as a mechanism to support multiple compilation contexts within a single module dependency graph.
The Swift compiler and the Explicitly-built modules model has long since abandoned this approach and this code has long been stale. It is time to remove it and its associated C API.

Author: artemcm

include/swift-c/DependencyScan/DependencyScan.h

@@ -292,48 +292,6 @@ swiftscan_clang_detail_get_cas_fs_root_id(swiftscan_module_details_t details);
 SWIFTSCAN_PUBLIC swiftscan_string_ref_t
 swiftscan_clang_detail_get_module_cache_key(swiftscan_module_details_t details);
 
-//=== Batch Scan Input Functions ------------------------------------------===//
-
-/// Create an \c swiftscan_batch_scan_input_t instance.
-/// The returned \c swiftscan_batch_scan_input_t is owned by the caller and must be disposed
-/// of using \c swiftscan_batch_scan_input_dispose .
-SWIFTSCAN_PUBLIC swiftscan_batch_scan_input_t *
-swiftscan_batch_scan_input_create();
-
-SWIFTSCAN_PUBLIC void
-swiftscan_batch_scan_input_set_modules(swiftscan_batch_scan_input_t *input,
-                                       int count,
-                                       swiftscan_batch_scan_entry_t *modules);
-
-//=== Batch Scan Entry Functions ------------------------------------------===//
-
-/// Create an \c swiftscan_batch_scan_entry_t instance.
-/// The returned \c swiftscan_batch_scan_entry_t is owned by the caller and must be disposed
-/// of using \c swiftscan_batch_scan_entry_dispose .
-SWIFTSCAN_PUBLIC swiftscan_batch_scan_entry_t
-swiftscan_batch_scan_entry_create();
-
-SWIFTSCAN_PUBLIC void
-swiftscan_batch_scan_entry_set_module_name(swiftscan_batch_scan_entry_t entry,
-                                           const char *name);
-
-SWIFTSCAN_PUBLIC void
-swiftscan_batch_scan_entry_set_arguments(swiftscan_batch_scan_entry_t entry,
-                                         const char *arguments);
-
-SWIFTSCAN_PUBLIC void
-swiftscan_batch_scan_entry_set_is_swift(swiftscan_batch_scan_entry_t entry,
-                                        bool is_swift);
-
-SWIFTSCAN_PUBLIC swiftscan_string_ref_t
-swiftscan_batch_scan_entry_get_module_name(swiftscan_batch_scan_entry_t entry);
-
-SWIFTSCAN_PUBLIC swiftscan_string_ref_t
-swiftscan_batch_scan_entry_get_arguments(swiftscan_batch_scan_entry_t entry);
-
-SWIFTSCAN_PUBLIC bool
-swiftscan_batch_scan_entry_get_is_swift(swiftscan_batch_scan_entry_t entry);
-
 //=== Prescan Result Functions --------------------------------------------===//
 
 SWIFTSCAN_PUBLIC swiftscan_string_set_t *
@@ -382,15 +340,6 @@ swiftscan_dependency_graph_dispose(swiftscan_dependency_graph_t result);
 SWIFTSCAN_PUBLIC void
 swiftscan_import_set_dispose(swiftscan_import_set_t result);
 
-SWIFTSCAN_PUBLIC void
-swiftscan_batch_scan_entry_dispose(swiftscan_batch_scan_entry_t entry);
-
-SWIFTSCAN_PUBLIC void
-swiftscan_batch_scan_input_dispose(swiftscan_batch_scan_input_t *input);
-
-SWIFTSCAN_PUBLIC void
-swiftscan_batch_scan_result_dispose(swiftscan_batch_scan_result_t *result);
-
 SWIFTSCAN_PUBLIC void
 swiftscan_scan_invocation_dispose(swiftscan_scan_invocation_t invocation);
 
@@ -427,15 +376,6 @@ SWIFTSCAN_PUBLIC void swiftscan_scanner_dispose(swiftscan_scanner_t);
 SWIFTSCAN_PUBLIC swiftscan_dependency_graph_t swiftscan_dependency_graph_create(
     swiftscan_scanner_t scanner, swiftscan_scan_invocation_t invocation);
 
-/// Invoke the scan for an input batch of modules specified in the
-/// \c swiftscan_batch_scan_input_t argument. The returned
-/// \c swiftscan_batch_scan_result_t is owned by the caller and must be disposed
-/// of using \c swiftscan_batch_scan_result_dispose .
-SWIFTSCAN_PUBLIC swiftscan_batch_scan_result_t *
-swiftscan_batch_scan_result_create(swiftscan_scanner_t scanner,
-                                   swiftscan_batch_scan_input_t *batch_input,
-                                   swiftscan_scan_invocation_t invocation);
-
 /// Invoke the import prescan using arguments specified in the \c
 /// swiftscan_scan_invocation_t argument. The returned \c swiftscan_import_set_t
 /// is owned by the caller and must be disposed of using \c

include/swift/AST/DiagnosticsFrontend.def

@@ -354,18 +354,10 @@ ERROR(placeholder_dependency_module_map_corrupted,none,
       "Swift placeholder dependency module map from %0 is malformed",
       (StringRef))
 
-ERROR(batch_scan_input_file_missing,none,
-      "cannot open batch dependencies scan input file from %0",
-      (StringRef))
-
 ERROR(const_extract_protocol_list_input_file_missing,none,
       "cannot open constant extraction protocol list input file from %0",
       (StringRef))
 
-ERROR(batch_scan_input_file_corrupted,none,
-      "batch dependencies scan input file from %0 is malformed",
-      (StringRef))
-
 ERROR(const_extract_protocol_list_input_file_corrupted,none,
       "constant extraction protocol list input file from %0 is malformed",
       (StringRef))

include/swift/AST/SearchPathOptions.h

@@ -530,9 +530,6 @@ class SearchPathOptions {
   /// A map of placeholder Swift module dependency information.
   std::string PlaceholderDependencyModuleMap;
 
-  /// A file containing modules we should perform batch scanning.
-  std::string BatchScanInputFilePath;
-
   /// A file containing a list of protocols whose conformances require const value extraction.
   std::string ConstGatherProtocolListFilePath;
 

include/swift/DependencyScan/DependencyScanImpl.h

@@ -224,12 +224,6 @@ struct swiftscan_module_details_s {
   };
 };
 
-struct swiftscan_batch_scan_entry_s {
-  swiftscan_string_ref_t module_name;
-  swiftscan_string_ref_t arguments;
-  bool is_swift;
-};
-
 struct swiftscan_import_set_s {
   /// The complete list of imports discovered
   swiftscan_string_set_t *imports;

include/swift/DependencyScan/DependencyScanningTool.h

@@ -97,17 +97,6 @@ class DependencyScanningTool {
   llvm::ErrorOr<swiftscan_import_set_t>
   getImports(ArrayRef<const char *> Command, StringRef WorkingDirectory);
 
-  /// Collect the full module dependency graph for the input collection of
-  /// module names (batch inputs) and output them to the
-  /// BatchScanInput-specified output locations.
-  ///
-  /// \returns a \c std::error_code if errors occurred during scan.
-  std::vector<llvm::ErrorOr<swiftscan_dependency_graph_t>>
-  getDependencies(ArrayRef<const char *> Command,
-                  const std::vector<BatchScanInput> &BatchInput,
-                  const llvm::StringSet<> &PlaceholderModules,
-                  StringRef WorkingDirectory);
-
   /// Query diagnostics consumed so far.
   std::vector<DependencyScanDiagnosticCollector::ScannerDiagnosticInfo> getDiagnostics();
   /// Discared the collection of diagnostics encountered so far.
@@ -125,10 +114,6 @@ class DependencyScanningTool {
   /// during the lifetime of this Tool.
   std::unique_ptr<SwiftDependencyScanningService> ScanningService;
 
-  /// Shared cache of compiler instances created during batch scanning, corresponding to
-  /// command-line options specified in the batch scan input entry.
-  std::unique_ptr<CompilerArgInstanceCacheMap> VersionedPCMInstanceCacheCache;
-
   /// Shared state mutual-exclusivity lock
   llvm::sys::SmartMutex<true> DependencyScanningToolStateLock;
 

include/swift/DependencyScan/ScanDependencies.h

@@ -37,13 +37,6 @@ using CompilerArgInstanceCacheMap =
                                std::unique_ptr<SwiftDependencyScanningService>,
                                std::unique_ptr<ModuleDependenciesCache>>>;
 
-struct BatchScanInput {
-  llvm::StringRef moduleName;
-  llvm::StringRef arguments;
-  llvm::StringRef outputPath;
-  bool isSwift;
-};
-
 // MARK: FrontendTool dependency scanner entry points
 /// Scans the dependencies of the main module of \c instance and writes out
 /// the resulting JSON according to the instance's output parameters.
@@ -52,10 +45,6 @@ bool scanDependencies(CompilerInstance &instance);
 /// Identify all imports in the translation unit's module.
 bool prescanDependencies(CompilerInstance &instance);
 
-/// Batch scan the dependencies for modules specified in \c batchInputFile.
-bool batchScanDependencies(CompilerInstance &instance,
-                           llvm::StringRef batchInputFile);
-
 // MARK: Dependency scanning execution
 /// Scans the dependencies of the main module of \c instance.
 llvm::ErrorOr<swiftscan_dependency_graph_t>
@@ -69,14 +58,6 @@ performModulePrescan(CompilerInstance &instance,
                      DependencyScanDiagnosticCollector *diagnostics,
                      ModuleDependenciesCache &cache);
 
-/// Batch scan the dependencies for modules specified in \c batchInputFile.
-std::vector<llvm::ErrorOr<swiftscan_dependency_graph_t>>
-performBatchModuleScan(CompilerInstance &invocationInstance,
-                       DependencyScanDiagnosticCollector *diagnostics,
-                       ModuleDependenciesCache &invocationCache,
-                       CompilerArgInstanceCacheMap *versionedPCMInstanceCache,
-                       llvm::StringSaver &saver,
-                       const std::vector<BatchScanInput> &BatchInput);
 } // end namespace dependencies
 } // end namespace swift
 

include/swift/Option/FrontendOptions.td

@@ -259,10 +259,6 @@ def placeholder_dependency_module_map
   : Separate<["-"], "placeholder-dependency-module-map-file">, MetaVarName<"<path>">,
     HelpText<"Specify a JSON file containing information of external Swift module dependencies">;
 
-def batch_scan_input_file
-  : Separate<["-"], "batch-scan-input-file">, MetaVarName<"<path>">,
-    HelpText<"Specify a JSON file containing modules to perform batch dependencies scanning">;
-
 def import_prescan : Flag<["-"], "import-prescan">,
    HelpText<"When performing a dependency scan, only identify all imports of the main Swift module sources">;
 

lib/DependencyScan/DependencyScanningTool.cpp

@@ -261,8 +261,6 @@ static swiftscan_import_set_t generateHollowDiagnosticOutputImportSet(
 
 DependencyScanningTool::DependencyScanningTool()
     : ScanningService(std::make_unique<SwiftDependencyScanningService>()),
-      VersionedPCMInstanceCacheCache(
-          std::make_unique<CompilerArgInstanceCacheMap>()),
       CDC(), Alloc(), Saver(Alloc) {}
 
 llvm::ErrorOr<swiftscan_dependency_graph_t>
@@ -327,35 +325,6 @@ DependencyScanningTool::getImports(ArrayRef<const char *> Command,
   return std::move(*DependenciesOrErr);
 }
 
-std::vector<llvm::ErrorOr<swiftscan_dependency_graph_t>>
-DependencyScanningTool::getDependencies(
-    ArrayRef<const char *> Command,
-    const std::vector<BatchScanInput> &BatchInput,
-    const llvm::StringSet<> &PlaceholderModules, StringRef WorkingDirectory) {
-  // The primary instance used to scan Swift modules
-  auto ScanDiagnosticConsumer = std::make_shared<DependencyScanDiagnosticCollector>();
-  auto QueryContextOrErr = initCompilerInstanceForScan(Command,
-                                                       WorkingDirectory,
-                                                       ScanDiagnosticConsumer);
-  if (std::error_code EC = QueryContextOrErr.getError())
-    return std::vector<llvm::ErrorOr<swiftscan_dependency_graph_t>>(
-        BatchInput.size(), std::make_error_code(std::errc::invalid_argument));
-
-  auto QueryContext = std::move(*QueryContextOrErr);
-
-  // Local scan cache instance, wrapping the shared global cache.
-  ModuleDependenciesCache cache(
-      *ScanningService, QueryContext.ScanInstance->getMainModule()->getNameStr().str(),
-      QueryContext.ScanInstance->getInvocation().getFrontendOptions().ExplicitModulesOutputPath,
-      QueryContext.ScanInstance->getInvocation().getModuleScanningHash());
-  auto BatchScanResults = performBatchModuleScan(
-      *QueryContext.ScanInstance.get(), QueryContext.ScanDiagnostics.get(),
-      cache, VersionedPCMInstanceCacheCache.get(),
-      Saver, BatchInput);
-
-  return BatchScanResults;
-}
-
 std::vector<
     DependencyScanDiagnosticCollector::ScannerDiagnosticInfo>
 DependencyScanningTool::getDiagnostics() {

lib/DependencyScan/ModuleDependencyScanner.cpp

@@ -78,7 +78,6 @@ findPathToDependency(ModuleDependencyID dependency,
                      const ModuleDependenciesCache &cache) {
   auto mainModuleDep = cache.findDependency(cache.getMainModuleName(),
                                             ModuleDependencyKind::SwiftSource);
-  // We may be in a batch scan instance which does not have this dependency
   if (!mainModuleDep.has_value())
     return {};
   auto mainModuleID = ModuleDependencyID{cache.getMainModuleName().str(),