4 files changed, 120 insertions, 9 deletions
diff --git a/clang-tools-extra/clangd/index/IndexAction.cpp b/clang-tools-extra/clangd/index/IndexAction.cpp
new file mode 100644
index 00000000000..b9dcb6e19c0
--- /dev/null
+++ b/clang-tools-extra/clangd/index/IndexAction.cpp
@@ -0,0 +1,73 @@
+#include "IndexAction.h"
+#include "clang/Frontend/CompilerInstance.h"
+#include "clang/Index/IndexDataConsumer.h"
+#include "clang/Index/IndexingAction.h"
+#include "clang/Tooling/Tooling.h"
+namespace clang {
+namespace clangd {
+namespace {
+
+// Wraps the index action and reports index data after each translation unit.
+class IndexAction : public WrapperFrontendAction {
+public:
+  IndexAction(std::shared_ptr<SymbolCollector> C,
+              std::unique_ptr<CanonicalIncludes> Includes,
+              const index::IndexingOptions &Opts,
+              std::function<void(SymbolSlab)> &SymbolsCallback)
+      : WrapperFrontendAction(index::createIndexingAction(C, Opts, nullptr)),
+        SymbolsCallback(SymbolsCallback), Collector(C),
+        Includes(std::move(Includes)),
+        PragmaHandler(collectIWYUHeaderMaps(this->Includes.get())) {}
+
+  std::unique_ptr<ASTConsumer> CreateASTConsumer(CompilerInstance &CI,
+                                                 StringRef InFile) override {
+    CI.getPreprocessor().addCommentHandler(PragmaHandler.get());
+    return WrapperFrontendAction::CreateASTConsumer(CI, InFile);
+  }
+
+  bool BeginInvocation(CompilerInstance &CI) override {
+    // We want all comments, not just the doxygen ones.
+    CI.getLangOpts().CommentOpts.ParseAllComments = true;
+    return WrapperFrontendAction::BeginInvocation(CI);
+  }
+
+  void EndSourceFileAction() override {
+    WrapperFrontendAction::EndSourceFileAction();
+
+    const auto &CI = getCompilerInstance();
+    if (CI.hasDiagnostics() &&
+        CI.getDiagnostics().hasUncompilableErrorOccurred()) {
+      llvm::errs() << "Skipping TU due to uncompilable errors\n";
+      return;
+    }
+    SymbolsCallback(Collector->takeSymbols());
+  }
+
+private:
+  std::function<void(SymbolSlab)> SymbolsCallback;
+  std::shared_ptr<SymbolCollector> Collector;
+  std::unique_ptr<CanonicalIncludes> Includes;
+  std::unique_ptr<CommentHandler> PragmaHandler;
+};
+
+} // namespace
+
+std::unique_ptr<FrontendAction>
+createStaticIndexingAction(SymbolCollector::Options Opts,
+                           std::function<void(SymbolSlab)> SymbolsCallback) {
+  index::IndexingOptions IndexOpts;
+  IndexOpts.SystemSymbolFilter =
+      index::IndexingOptions::SystemSymbolFilterKind::All;
+  Opts.CollectIncludePath = true;
+  Opts.CountReferences = true;
+  Opts.Origin = SymbolOrigin::Static;
+  auto Includes = llvm::make_unique<CanonicalIncludes>();
+  addSystemHeadersMapping(Includes.get());
+  Opts.Includes = Includes.get();
+  return llvm::make_unique<IndexAction>(
+      std::make_shared<SymbolCollector>(std::move(Opts)), std::move(Includes),
+      IndexOpts, SymbolsCallback);
+};
+
+} // namespace clangd
+} // namespace clang
diff --git a/clang-tools-extra/clangd/index/IndexAction.h b/clang-tools-extra/clangd/index/IndexAction.h
new file mode 100644
index 00000000000..b51bfd2520f
--- /dev/null
+++ b/clang-tools-extra/clangd/index/IndexAction.h
@@ -0,0 +1,32 @@
+//===--- IndexAction.h - Run the indexer as a frontend action ----*- C++-*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_TOOLS_EXTRA_CLANGD_INDEX_INDEX_ACTION_H
+#define LLVM_CLANG_TOOLS_EXTRA_CLANGD_INDEX_INDEX_ACTION_H
+#include "SymbolCollector.h"
+#include "clang/Frontend/FrontendActions.h"
+
+namespace clang {
+namespace clangd {
+
+// Creates an action that indexes translation units and delivers the results
+// for SymbolsCallback (each slab corresponds to one TU).
+//
+// Only a subset of SymbolCollector::Options are respected:
+//   - include paths are always collected, and canonicalized appropriately
+//   - references are always counted
+//   - the symbol origin is always Static
+std::unique_ptr<FrontendAction>
+createStaticIndexingAction(SymbolCollector::Options Opts,
+                           std::function<void(SymbolSlab)> SymbolsCallback);
+
+} // namespace clangd
+} // namespace clang
+
+#endif
diff --git a/clang-tools-extra/clangd/index/Serialization.h b/clang-tools-extra/clangd/index/Serialization.h
index c73ce23b5e5..4240bdb722b 100644
--- a/clang-tools-extra/clangd/index/Serialization.h
+++ b/clang-tools-extra/clangd/index/Serialization.h
@@ -40,23 +40,26 @@ enum class IndexFileFormat {
   YAML, // Human-readable format, suitable for experiments and debugging.
 };
 
+// Holds the contents of an index file that was read.
+struct IndexFileIn {
+  llvm::Optional<SymbolSlab> Symbols;
+};
+// Parse an index file. The input must be a RIFF container chunk.
+llvm::Expected<IndexFileIn> readIndexFile(llvm::StringRef);
+
 // Specifies the contents of an index file to be written.
 struct IndexFileOut {
   const SymbolSlab *Symbols;
   // TODO: Support serializing symbol occurrences.
   // TODO: Support serializing Dex posting lists.
   IndexFileFormat Format = IndexFileFormat::RIFF;
-};
-// Serializes an index file. (This is a RIFF container chunk).
-llvm::raw_ostream &operator<<(llvm::raw_ostream &OS, const IndexFileOut &O);
 
-// Holds the contents of an index file that was read.
-struct IndexFileIn {
-  llvm::Optional<SymbolSlab> Symbols;
-  IndexFileFormat Format;
+  IndexFileOut() = default;
+  IndexFileOut(const IndexFileIn &I)
+      : Symbols(I.Symbols ? I.Symbols.getPointer() : nullptr) {}
 };
-// Parse an index file. The input must be a RIFF container chunk.
-llvm::Expected<IndexFileIn> readIndexFile(llvm::StringRef);
+// Serializes an index file.
+llvm::raw_ostream &operator<<(llvm::raw_ostream &OS, const IndexFileOut &O);
 
 std::string toYAML(const Symbol &);
 // Returned symbol is backed by the YAML input.
diff --git a/clang-tools-extra/clangd/index/SymbolCollector.h b/clang-tools-extra/clangd/index/SymbolCollector.h
index db0e3074ecf..1994183c21e 100644
--- a/clang-tools-extra/clangd/index/SymbolCollector.h
+++ b/clang-tools-extra/clangd/index/SymbolCollector.h
@@ -6,6 +6,8 @@
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
+#ifndef LLVM_CLANG_TOOLS_EXTRA_CLANGD_INDEX_SYMBOL_COLLECTOR_H
+#define LLVM_CLANG_TOOLS_EXTRA_CLANGD_INDEX_SYMBOL_COLLECTOR_H
 
 #include "CanonicalIncludes.h"
 #include "Index.h"
@@ -122,3 +124,4 @@ private:
 
 } // namespace clangd
 } // namespace clang
+#endif