[clang-scan-deps] Add an API for clang dependency scanner to perform

module lookup by name alone

This removes the need to create a fake source file that imports a
module.

rdar://64538073

Differential Revision: https://reviews.llvm.org/D109485

1 files changed, 14 insertions, 0 deletions

diff --git a/clang/lib/Frontend/FrontendActions.cpp b/clang/lib/Frontend/FrontendActions.cpp
index c6ebbdc..b5544af 100644
--- a/clang/lib/Frontend/FrontendActions.cpp
+++ b/clang/lib/Frontend/FrontendActions.cpp
@@ -993,3 +993,17 @@ void PrintDependencyDirectivesSourceMinimizerAction::ExecuteAction() {
   }
   llvm::outs() << Output;
 }
+
+void GetDependenciesByModuleNameAction::ExecuteAction() {
+  CompilerInstance &CI = getCompilerInstance();
+  Preprocessor &PP = CI.getPreprocessor();
+  SourceManager &SM = PP.getSourceManager();
+  FileID MainFileID = SM.getMainFileID();
+  SourceLocation FileStart = SM.getLocForStartOfFile(MainFileID);
+  SmallVector<std::pair<IdentifierInfo *, SourceLocation>, 2> Path;
+  IdentifierInfo *ModuleID = PP.getIdentifierInfo(ModuleName);
+  Path.push_back(std::make_pair(ModuleID, FileStart));
+  auto ModResult = CI.loadModule(FileStart, Path, Module::Hidden, false);
+  PPCallbacks *CB = PP.getPPCallbacks();
+  CB->moduleImport(SourceLocation(), Path, ModResult);
+}