1 files changed, 118 insertions, 0 deletions
diff --git a/clang/unittests/Tooling/DependencyScannerTest.cpp b/clang/unittests/Tooling/DependencyScannerTest.cpp
new file mode 100644
index 00000000000..fa60d0a7524
--- /dev/null
+++ b/clang/unittests/Tooling/DependencyScannerTest.cpp
@@ -0,0 +1,118 @@
+//===- unittest/Tooling/ToolingTest.cpp - Tooling unit tests --------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/AST/ASTConsumer.h"
+#include "clang/AST/DeclCXX.h"
+#include "clang/AST/DeclGroup.h"
+#include "clang/Frontend/ASTUnit.h"
+#include "clang/Frontend/CompilerInstance.h"
+#include "clang/Frontend/FrontendAction.h"
+#include "clang/Frontend/FrontendActions.h"
+#include "clang/Tooling/CompilationDatabase.h"
+#include "clang/Tooling/Tooling.h"
+#include "llvm/ADT/STLExtras.h"
+#include "llvm/Support/Path.h"
+#include "llvm/Support/TargetRegistry.h"
+#include "llvm/Support/TargetSelect.h"
+#include "gtest/gtest.h"
+#include <algorithm>
+#include <string>
+
+namespace clang {
+namespace tooling {
+
+namespace {
+
+/// Prints out all of the gathered dependencies into a string.
+class TestFileCollector : public DependencyFileGenerator {
+public:
+  TestFileCollector(DependencyOutputOptions &Opts,
+                    std::vector<std::string> &Deps)
+      : DependencyFileGenerator(Opts), Deps(Deps) {}
+
+  void finishedMainFile(DiagnosticsEngine &Diags) override {
+    Deps = getDependencies();
+  }
+
+private:
+  std::vector<std::string> &Deps;
+};
+
+class TestDependencyScanningAction : public tooling::ToolAction {
+public:
+  TestDependencyScanningAction(std::vector<std::string> &Deps) : Deps(Deps) {}
+
+  bool runInvocation(std::shared_ptr<CompilerInvocation> Invocation,
+                     FileManager *FileMgr,
+                     std::shared_ptr<PCHContainerOperations> PCHContainerOps,
+                     DiagnosticConsumer *DiagConsumer) override {
+    CompilerInstance Compiler(std::move(PCHContainerOps));
+    Compiler.setInvocation(std::move(Invocation));
+    Compiler.setFileManager(FileMgr);
+
+    Compiler.createDiagnostics(DiagConsumer, /*ShouldOwnClient=*/false);
+    if (!Compiler.hasDiagnostics())
+      return false;
+
+    Compiler.createSourceManager(*FileMgr);
+    Compiler.addDependencyCollector(std::make_shared<TestFileCollector>(
+        Compiler.getInvocation().getDependencyOutputOpts(), Deps));
+
+    auto Action = std::make_unique<PreprocessOnlyAction>();
+    return Compiler.ExecuteAction(*Action);
+  }
+
+private:
+  std::vector<std::string> &Deps;
+};
+
+} // namespace
+
+TEST(DependencyScanner, ScanDepsReuseFilemanager) {
+  std::vector<std::string> Compilation = {"-c", "-E", "-MT", "test.cpp.o"};
+  StringRef CWD = "/root";
+  FixedCompilationDatabase CDB(CWD, Compilation);
+
+  auto VFS = new llvm::vfs::InMemoryFileSystem();
+  VFS->setCurrentWorkingDirectory(CWD);
+  VFS->addFile("/root/header.h", 0, llvm::MemoryBuffer::getMemBuffer("\n"));
+  VFS->addHardLink("/root/symlink.h", "/root/header.h");
+  VFS->addFile("/root/test.cpp", 0,
+               llvm::MemoryBuffer::getMemBuffer(
+                   "#include \"symlink.h\"\n#include \"header.h\"\n"));
+
+  ClangTool Tool(CDB, {"test.cpp"}, std::make_shared<PCHContainerOperations>(),
+                 VFS);
+  Tool.clearArgumentsAdjusters();
+  std::vector<std::string> Deps;
+  TestDependencyScanningAction Action(Deps);
+  Tool.run(&Action);
+  // The first invocation should return dependencies in order of access.
+  ASSERT_EQ(Deps.size(), 3u);
+  EXPECT_EQ(Deps[0], "/root/test.cpp");
+  EXPECT_EQ(Deps[1], "/root/symlink.h");
+  EXPECT_EQ(Deps[2], "/root/header.h");
+
+  // The file manager should still have two FileEntries, as one file is a
+  // hardlink.
+  FileManager &Files = Tool.getFiles();
+  EXPECT_EQ(Files.getNumUniqueRealFiles(), 2u);
+
+  Deps.clear();
+  Tool.run(&Action);
+  // The second invocation should have the same order of dependencies.
+  ASSERT_EQ(Deps.size(), 3u);
+  EXPECT_EQ(Deps[0], "/root/test.cpp");
+  EXPECT_EQ(Deps[1], "/root/symlink.h");
+  EXPECT_EQ(Deps[2], "/root/header.h");
+
+  EXPECT_EQ(Files.getNumUniqueRealFiles(), 2u);
+}
+
+} // end namespace tooling
+} // end namespace clang