diff --git a/clang/include/clang/Tooling/DependencyScanning/DependencyScanningTool.h b/clang/include/clang/Tooling/DependencyScanning/DependencyScanningTool.h
--- a/clang/include/clang/Tooling/DependencyScanning/DependencyScanningTool.h
+++ b/clang/include/clang/Tooling/DependencyScanning/DependencyScanningTool.h
@@ -83,8 +83,8 @@
   /// \returns A \c StringError with the diagnostic output if clang errors
   /// occurred, dependency file contents otherwise.
   llvm::Expected<std::string>
-  getDependencyFile(const tooling::CompilationDatabase &Compilations,
-                    StringRef CWD, llvm::Optional<StringRef> ModuleName = None);
+  getDependencyFile(const std::vector<std::string> &CommandLine, StringRef CWD,
+                    llvm::Optional<StringRef> ModuleName = None);
 
   /// Collect the full module dependency graph for the input, ignoring any
   /// modules which have already been seen. If \p ModuleName isn't empty, this
@@ -99,7 +99,7 @@
   /// \returns a \c StringError with the diagnostic output if clang errors
   /// occurred, \c FullDependencies otherwise.
   llvm::Expected<FullDependenciesResult>
-  getFullDependencies(const tooling::CompilationDatabase &Compilations,
+  getFullDependencies(const std::vector<std::string> &CommandLine,
                       StringRef CWD, const llvm::StringSet<> &AlreadySeen,
                       llvm::Optional<StringRef> ModuleName = None);
 
diff --git a/clang/include/clang/Tooling/DependencyScanning/DependencyScanningWorker.h b/clang/include/clang/Tooling/DependencyScanning/DependencyScanningWorker.h
--- a/clang/include/clang/Tooling/DependencyScanning/DependencyScanningWorker.h
+++ b/clang/include/clang/Tooling/DependencyScanning/DependencyScanningWorker.h
@@ -14,7 +14,6 @@
 #include "clang/Basic/LLVM.h"
 #include "clang/Frontend/PCHContainerOperations.h"
 #include "clang/Lex/PreprocessorExcludedConditionalDirectiveSkipMapping.h"
-#include "clang/Tooling/CompilationDatabase.h"
 #include "clang/Tooling/DependencyScanning/DependencyScanningService.h"
 #include "clang/Tooling/DependencyScanning/ModuleDepCollector.h"
 #include "llvm/Support/Error.h"
@@ -30,24 +29,6 @@
 
 class DependencyScanningWorkerFilesystem;
 
-/// Compilation database that holds and reports a single compile command.
-class SingleCommandCompilationDatabase : public CompilationDatabase {
-  CompileCommand Command;
-
-public:
-  SingleCommandCompilationDatabase(CompileCommand Cmd)
-      : Command(std::move(Cmd)) {}
-
-  std::vector<CompileCommand>
-  getCompileCommands(StringRef FilePath) const override {
-    return {Command};
-  }
-
-  std::vector<CompileCommand> getAllCompileCommands() const override {
-    return {Command};
-  }
-};
-
 class DependencyConsumer {
 public:
   virtual ~DependencyConsumer() {}
diff --git a/clang/lib/Tooling/DependencyScanning/DependencyScanningTool.cpp b/clang/lib/Tooling/DependencyScanning/DependencyScanningTool.cpp
--- a/clang/lib/Tooling/DependencyScanning/DependencyScanningTool.cpp
+++ b/clang/lib/Tooling/DependencyScanning/DependencyScanningTool.cpp
@@ -50,7 +50,7 @@
     : Worker(Service) {}
 
 llvm::Expected<std::string> DependencyScanningTool::getDependencyFile(
-    const tooling::CompilationDatabase &Compilations, StringRef CWD,
+    const std::vector<std::string> &CommandLine, StringRef CWD,
     llvm::Optional<StringRef> ModuleName) {
   /// Prints out all of the gathered dependencies into a string.
   class MakeDependencyPrinterConsumer : public DependencyConsumer {
@@ -103,17 +103,6 @@
     std::vector<std::string> Dependencies;
   };
 
-  // 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!");
-  // FIXME: Avoid this copy.
-  std::vector<std::string> CommandLine =
-      Compilations.getAllCompileCommands().front().CommandLine;
-
   MakeDependencyPrinterConsumer Consumer;
   auto Result =
       Worker.computeDependencies(CWD, CommandLine, Consumer, ModuleName);
@@ -126,7 +115,7 @@
 
 llvm::Expected<FullDependenciesResult>
 DependencyScanningTool::getFullDependencies(
-    const tooling::CompilationDatabase &Compilations, StringRef CWD,
+    const std::vector<std::string> &CommandLine, StringRef CWD,
     const llvm::StringSet<> &AlreadySeen,
     llvm::Optional<StringRef> ModuleName) {
   class FullDependencyPrinterConsumer : public DependencyConsumer {
@@ -191,17 +180,6 @@
     const llvm::StringSet<> &AlreadySeen;
   };
 
-  // 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!");
-  // FIXME: Avoid this copy.
-  std::vector<std::string> CommandLine =
-      Compilations.getAllCompileCommands().front().CommandLine;
-
   FullDependencyPrinterConsumer Consumer(AlreadySeen);
   llvm::Error Result =
       Worker.computeDependencies(CWD, CommandLine, Consumer, ModuleName);
diff --git a/clang/tools/clang-scan-deps/ClangScanDeps.cpp b/clang/tools/clang-scan-deps/ClangScanDeps.cpp
--- a/clang/tools/clang-scan-deps/ClangScanDeps.cpp
+++ b/clang/tools/clang-scan-deps/ClangScanDeps.cpp
@@ -513,10 +513,8 @@
   for (unsigned I = 0; I < Pool.getThreadCount(); ++I)
     WorkerTools.push_back(std::make_unique<DependencyScanningTool>(Service));
 
-  std::vector<SingleCommandCompilationDatabase> Inputs;
-  for (tooling::CompileCommand Cmd :
-       AdjustingCompilations->getAllCompileCommands())
-    Inputs.emplace_back(Cmd);
+  std::vector<tooling::CompileCommand> Inputs =
+      AdjustingCompilations->getAllCompileCommands();
 
   std::atomic<bool> HadErrors(false);
   FullDeps FD;
@@ -532,7 +530,7 @@
                 &DependencyOS, &Errs]() {
       llvm::StringSet<> AlreadySeenModules;
       while (true) {
-        const SingleCommandCompilationDatabase *Input;
+        const tooling::CompileCommand *Input;
         std::string Filename;
         std::string CWD;
         size_t LocalIndex;
@@ -543,14 +541,13 @@
             return;
           LocalIndex = Index;
           Input = &Inputs[Index++];
-          tooling::CompileCommand Cmd = Input->getAllCompileCommands()[0];
-          Filename = std::move(Cmd.Filename);
-          CWD = std::move(Cmd.Directory);
+          Filename = std::move(Input->Filename);
+          CWD = std::move(Input->Directory);
         }
         // Run the tool on it.
         if (Format == ScanningOutputFormat::Make) {
           auto MaybeFile = WorkerTools[I]->getDependencyFile(
-              *Input, CWD,
+              Input->CommandLine, CWD,
               ModuleName.empty()
                   ? None
                   : llvm::Optional<StringRef>(ModuleName.c_str()));
@@ -559,7 +556,7 @@
             HadErrors = true;
         } else {
           auto MaybeFullDeps = WorkerTools[I]->getFullDependencies(
-              *Input, CWD, AlreadySeenModules,
+              Input->CommandLine, CWD, AlreadySeenModules,
               ModuleName.empty()
                   ? None
                   : llvm::Optional<StringRef>(ModuleName.c_str()));