test: add an IDE test for loading modules from explict module map

Author: nkcsgexi

test/ScanDependencies/explicit-module-map.swift

@@ -0,0 +1,18 @@
+// RUN: %empty-directory(%t)
+// RUN: mkdir -p %t/clang-module-cache
+// RUN: mkdir -p %t/inputs
+// RUN: echo "/// Some cool comments" > %t/foo.swift
+// RUN: echo "public func foo() {}" >> %t/foo.swift
+// RUN: %target-swift-frontend -emit-module -emit-module-path %t/inputs/Foo.swiftmodule -emit-module-doc-path %t/inputs/Foo.swiftdoc -emit-module-source-info -emit-module-source-info-path %t/inputs/Foo.swiftsourceinfo -module-cache-path %t.module-cache %t/foo.swift -module-name Foo
+
+// RUN: echo "{" > %t/inputs/map.json
+// RUN: echo "\"Foo\": {" >> %t/inputs/map.json
+// RUN: echo "\"SwiftModulePath\": \"%t/inputs/Foo.swiftmodule\"," >> %t/inputs/map.json
+// RUN: echo "\"SwiftDocPath\": \"%t/inputs/Foo.swiftdoc\"," >> %t/inputs/map.json
+// RUN: echo "\"SwiftSourceInfoPath\": \"%t/inputs/Foo.swiftsourceinfo\"" >> %t/inputs/map.json
+// RUN: echo "}" >> %t/inputs/map.json
+// RUN: echo "}" >> %t/inputs/map.json
+
+// RUN: %target-swift-ide-test -print-module-comments -module-to-print=Foo -enable-swiftsourceinfo -source-filename %s -explicit-swift-module-map-file %t/inputs/map.json | %FileCheck %s
+
+// CHECK: foo.swift:2:13: Func/foo RawComment=[/// Some cool comments

tools/swift-ide-test/swift-ide-test.cpp

@@ -723,6 +723,10 @@ EnableSwiftSourceInfo("enable-swiftsourceinfo",
                  llvm::cl::cat(Category),
                  llvm::cl::init(false));
 
+static llvm::cl::opt<std::string>
+ExplicitSwiftModuleMap("explicit-swift-module-map-file",
+                       llvm::cl::desc("JSON file to include explicit Swift modules"),
+                       llvm::cl::cat(Category));
 } // namespace options
 
 static std::unique_ptr<llvm::MemoryBuffer>
@@ -3462,6 +3466,11 @@ int main(int argc, char *argv[]) {
   for (auto ConfigName : options::BuildConfigs)
     InitInvok.getLangOptions().addCustomConditionalCompilationFlag(ConfigName);
 
+  if (!options::ExplicitSwiftModuleMap.empty()) {
+    InitInvok.getSearchPathOptions().ExplicitSwiftModuleMap =
+      options::ExplicitSwiftModuleMap;
+    InitInvok.getFrontendOptions().DisableImplicitModules = true;
+  }
   // Process the clang arguments last and allow them to override previously
   // set options.
   if (!CCArgs.empty()) {