ExplicitModuleLoader: allow explicit module input map to indicate whether a module is a system module

Author: nkcsgexi

include/swift/Frontend/ModuleInterfaceLoader.h

@@ -181,6 +181,9 @@ struct ExplicitModuleInfo {
   std::string moduleSourceInfoPath;
   // A flag that indicates whether this module is a framework
   bool isFramework;
+  // A flag that indicates whether this module is a system module
+  // Set the default to be false.
+  bool isSystem = false;
 };
 
 /// Parser of explicit module maps passed into the compiler.
@@ -239,7 +242,18 @@ class ExplicitModuleMapParser {
     SmallString<32> Buffer;
     return Saver.save(cast<llvm::yaml::ScalarNode>(N)->getValue(Buffer));
   }
-  
+
+  static bool parseBoolValue(StringRef val) {
+    auto valStr = val.str();
+    valStr.erase(std::remove(valStr.begin(), valStr.end(), '\n'), valStr.end());
+    if (valStr.compare("true") == 0)
+      return true;
+    else if (valStr.compare("false") == 0)
+      return false;
+    else
+      llvm_unreachable("Unexpected JSON value for isFramework");
+  }
+
   bool parseSingleModuleEntry(llvm::yaml::Node &node,
                               llvm::StringMap<ExplicitModuleInfo> &moduleMap) {
     using namespace llvm::yaml;
@@ -260,14 +274,9 @@ class ExplicitModuleMapParser {
       } else if (key == "sourceInfoPath") {
         result.moduleSourceInfoPath = val.str();
       } else if (key == "isFramework") {
-        auto valStr = val.str();
-        valStr.erase(std::remove(valStr.begin(), valStr.end(), '\n'), valStr.end());
-        if (valStr.compare("true") == 0)
-          result.isFramework = true;
-        else if (valStr.compare("false") == 0)
-          result.isFramework = false;
-        else
-          llvm_unreachable("Unexpected JSON value for isFramework");
+        result.isFramework = parseBoolValue(val);
+      } else if (key == "isSystem") {
+        result.isSystem = parseBoolValue(val);
       } else {
         // Being forgiving for future fields.
         continue;

lib/Frontend/ModuleInterfaceLoader.cpp

@@ -1722,6 +1722,7 @@ bool ExplicitSwiftModuleLoader::findModule(ImportPath::Element ModuleID,
 
   // Set IsFramework bit according to the moduleInfo
   IsFramework = moduleInfo.isFramework;
+  IsSystemModule = moduleInfo.isSystem;
 
   auto &fs = *Ctx.SourceMgr.getFileSystem();
   // Open .swiftmodule file

test/ScanDependencies/placholder_overlay_deps.swift

@@ -7,7 +7,8 @@
 // RUN: echo "\"modulePath\": \"%/t/inputs/Darwin.swiftmodule\"," >> %/t/inputs/map.json
 // RUN: echo "\"docPath\": \"%/t/inputs/Darwin.swiftdoc\"," >> %/t/inputs/map.json
 // RUN: echo "\"sourceInfoPath\": \"%/t/inputs/Darwin.swiftsourceinfo\"," >> %/t/inputs/map.json
-// RUN: echo "\"isFramework\": false" >> %/t/inputs/map.json
+// RUN: echo "\"isFramework\": false," >> %/t/inputs/map.json
+// RUN: echo "\"isSystem\": true" >> %/t/inputs/map.json
 // RUN: echo "}]" >> %/t/inputs/map.json
 
 // RUN: %target-swift-frontend -scan-dependencies -module-cache-path %t/clang-module-cache %s -placeholder-dependency-module-map-file %t/inputs/map.json -o %t/deps.json