Add option to accept external module dependency map as input

With: `-external-dependency-module-map-file`

Author: artemcm

include/swift/AST/DiagnosticsDriver.def

@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
+// Copyright (c) 2014 - 2020 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -122,6 +122,9 @@ ERROR(error_conflicting_options, none,
 ERROR(error_option_not_supported, none,
       "'%0' is not supported with '%1'",
       (StringRef, StringRef))
+ERROR(error_requirement_not_met, none,
+      "'%0' requires '%1'",
+      (StringRef, StringRef))
 
 WARNING(warn_ignore_embed_bitcode, none,
         "ignoring -embed-bitcode since no object file is being generated", ())

include/swift/AST/DiagnosticsFrontend.def

@@ -266,6 +266,14 @@ ERROR(explicit_swift_module_map_corrupted,none,
       "explicit Swift module map from %0 is malformed",
       (StringRef))
 
+ERROR(external_dependency_module_map_missing,none,
+      "cannot open Swift external dependency module map from %0",
+      (StringRef))
+
+ERROR(external_dependency_module_map_corrupted,none,
+      "Swift external dependency module map from %0 is malformed",
+      (StringRef))
+
 REMARK(default_previous_install_name, none,
       "default previous install name for %0 is %1", (StringRef, StringRef))
 

include/swift/AST/SearchPathOptions.h

@@ -90,6 +90,9 @@ class SearchPathOptions {
 
   /// A map of explict Swift module information.
   std::string ExplicitSwiftModuleMap;
+
+  /// A map of external Swift module dependency information.
+  std::string ExternalDependencyModuleMap;
 private:
   static StringRef
   pathStringFromFrameworkSearchPath(const FrameworkSearchPath &next) {

include/swift/Option/FrontendOptions.td

@@ -224,6 +224,10 @@ def swift_module_file
 def explict_swift_module_map
   : Separate<["-"], "explicit-swift-module-map-file">, MetaVarName<"<path>">,
     HelpText<"Specify a JSON file containing information of explict Swift modules">;
+
+def external_dependency_module_map
+  : Separate<["-"], "external-dependency-module-map-file">, MetaVarName<"<path>">,
+    HelpText<"Specify a JSON file containing information of external Swift module dependencies">;
 }
 
 

lib/Driver/Driver.cpp

@@ -163,6 +163,16 @@ static void validateProfilingArgs(DiagnosticEngine &diags,
   }
 }
 
+static void validateDependencyScanningArgs(DiagnosticEngine &diags,
+                                           const ArgList &args) {
+  const Arg *ExternalDependencyMap = args.getLastArg(options::OPT_external_dependency_module_map);
+  const Arg *ScanDependencies = args.getLastArg(options::OPT_scan_dependencies);
+  if (ExternalDependencyMap && !ScanDependencies) {
+    diags.diagnose(SourceLoc(), diag::error_conflicting_options,
+                   "-external-dependency-module-map-file", "-scan-dependencies");
+  }
+}
+
 static void validateDebugInfoArgs(DiagnosticEngine &diags,
                                   const ArgList &args) {
   // Check for missing debug option when verifying debug info.
@@ -261,6 +271,7 @@ static void validateArgs(DiagnosticEngine &diags, const ArgList &args,
   validateBridgingHeaderArgs(diags, args);
   validateWarningControlArgs(diags, args);
   validateProfilingArgs(diags, args);
+  validateDependencyScanningArgs(diags, args);
   validateDebugInfoArgs(diags, args);
   validateCompilationConditionArgs(diags, args);
   validateSearchPathArgs(diags, args);

lib/Frontend/CompilerInvocation.cpp

@@ -905,6 +905,8 @@ static bool ParseSearchPathArgs(SearchPathOptions &Opts,
   for (auto A: Args.filtered(OPT_candidate_module_file)) {
     Opts.CandidateCompiledModules.push_back(resolveSearchPath(A->getValue()));
   }
+  if (const Arg *A = Args.getLastArg(OPT_external_dependency_module_map))
+    Opts.ExternalDependencyModuleMap = A->getValue();
 
   // Opts.RuntimeIncludePath is set by calls to
   // setRuntimeIncludePath() or setMainExecutablePath().