[clang][deps] NFC: Remove CompilationDatabase from DependencyScanningWorker API

[jansvoboda11]

Summary

This patch simplifies the dependency scanner API. Depends on D108979.

[dexonsmith]

LGTM.

clang/include/clang/Tooling/DependencyScanning/DependencyScanningWorker.h

 ///
 /// The worker computes the dependencies for the input files by preprocessing
 /// sources either using a fast mode where the source files are minimized, or
 /// using the regular processing run.
 class DependencyScanningWorker {
 public:
   DependencyScanningWorker(DependencyScanningService &Service);
 
-  /// Run the dependency scanning tool for a given clang driver invocation (as
-  /// specified for the given Input in the CDB), and report the discovered
-  /// dependencies to the provided consumer. If \p ModuleName isn't empty, this
-  /// function reports the dependencies of module \p ModuleName.
+  /// Run the dependency scanning tool for a given clang driver command-line,
+  /// and report the discovered dependencies to the provided consumer. If \p
+  /// ModuleName isn't empty, this function reports the dependencies of module
+  /// \p ModuleName.
   ///
   /// \returns A \c StringError with the diagnostic output if clang errors
   /// occurred, success otherwise.
-  llvm::Error computeDependencies(const std::string &Input,
-                                  StringRef WorkingDirectory,
-                                  const CompilationDatabase &CDB,
+  llvm::Error computeDependencies(StringRef WorkingDirectory,
+                                  const std::vector<std::string> &CommandLine,
                                   DependencyConsumer &Consumer,
                                   llvm::Optional<StringRef> ModuleName = None);
 
 private:
   IntrusiveRefCntPtr<DiagnosticOptions> DiagOpts;
   std::shared_ptr<PCHContainerOperations> PCHContainerOps;
   std::unique_ptr<ExcludedPreprocessorDirectiveSkipMapping> PPSkipMappings;
 

clang/lib/Tooling/DependencyScanning/DependencyScanningTool.cpp

llvm::Expected<std::string> DependencyScanningTool::getDependencyFile(
 
   // We expect a single command here because if a source file occurs multiple
   // times in the original CDB, then `computeDependencies` would run the
   // `DependencyScanningAction` once for every time the input occured in the
   // CDB. Instead we split up the CDB into single command chunks to avoid this
   // behavior.
   assert(Compilations.getAllCompileCommands().size() == 1 &&
          "Expected a compilation database with a single command!");
-  std::string Input = Compilations.getAllCompileCommands().front().Filename;
+  // FIXME: Avoid this copy.
+  std::vector<std::string> CommandLine =
+      Compilations.getAllCompileCommands().front().CommandLine;
 
   MakeDependencyPrinterConsumer Consumer;
-  auto Result = Worker.computeDependencies(Input, CWD, Compilations, Consumer,
-                                           ModuleName);
+  auto Result =
+      Worker.computeDependencies(CWD, CommandLine, Consumer, ModuleName);
   if (Result)
     return std::move(Result);
   std::string Output;
   Consumer.printDependencies(Output);
   return Output;
 }
 
 llvm::Expected<FullDependenciesResult>
DependencyScanningTool::getFullDependencies(
 
   // We expect a single command here because if a source file occurs multiple
   // times in the original CDB, then `computeDependencies` would run the
   // `DependencyScanningAction` once for every time the input occured in the
   // CDB. Instead we split up the CDB into single command chunks to avoid this
   // behavior.
   assert(Compilations.getAllCompileCommands().size() == 1 &&
          "Expected a compilation database with a single command!");
-  std::string Input = Compilations.getAllCompileCommands().front().Filename;
+  // FIXME: Avoid this copy.
+  std::vector<std::string> CommandLine =
+      Compilations.getAllCompileCommands().front().CommandLine;
 
   FullDependencyPrinterConsumer Consumer(AlreadySeen);
-  llvm::Error Result = Worker.computeDependencies(Input, CWD, Compilations,
-                                                  Consumer, ModuleName);
+  llvm::Error Result =
+      Worker.computeDependencies(CWD, CommandLine, Consumer, ModuleName);
   if (Result)
     return std::move(Result);
   return Consumer.getFullDependencies();
 }
 
 } // end namespace dependencies
 } // end namespace tooling
 } // end namespace clang

clang/lib/Tooling/DependencyScanning/DependencyScanningWorker.cpp

static llvm::Error runWithDiags(
 
   if (BodyShouldSucceed(DiagPrinter))
     return llvm::Error::success();
   return llvm::make_error<llvm::StringError>(DiagnosticsOS.str(),
                                              llvm::inconvertibleErrorCode());
 }
 
 llvm::Error DependencyScanningWorker::computeDependencies(
-    const std::string &Input, StringRef WorkingDirectory,
-    const CompilationDatabase &CDB, DependencyConsumer &Consumer,
-    llvm::Optional<StringRef> ModuleName) {
+    StringRef WorkingDirectory, const std::vector<std::string> &CommandLine,
+    DependencyConsumer &Consumer, llvm::Optional<StringRef> ModuleName) {
   // Reset what might have been modified in the previous worker invocation.
   RealFS->setCurrentWorkingDirectory(WorkingDirectory);
   if (Files)
     Files->setVirtualFileSystem(RealFS);
 
   llvm::IntrusiveRefCntPtr<FileManager> CurrentFiles =
       Files ? Files : new FileManager(FileSystemOptions(), RealFS);
 
-  // FIXME: Avoid this copy.
-  std::vector<CompileCommand> CompileCommands = CDB.getCompileCommands(Input);
-  const std::vector<std::string> &CommandLine =
-      CompileCommands.front().CommandLine;
-
   Optional<std::vector<std::string>> ModifiedCommandLine;
   if (ModuleName.hasValue()) {
     ModifiedCommandLine = CommandLine;
     InMemoryFS->addFile(*ModuleName, 0, llvm::MemoryBuffer::getMemBuffer(""));
     ModifiedCommandLine->emplace_back(*ModuleName);
   }
 
   const std::vector<std::string> &FinalCommandLine =