diff --git a/clang-tools-extra/clangd/Preamble.h b/clang-tools-extra/clangd/Preamble.h
--- a/clang-tools-extra/clangd/Preamble.h
+++ b/clang-tools-extra/clangd/Preamble.h
@@ -43,7 +43,7 @@
 /// As we must avoid re-parsing the preamble, any information that can only
 /// be obtained during parsing must be eagerly captured and stored here.
 struct PreambleData {
-  PreambleData(llvm::StringRef Version, PrecompiledPreamble Preamble,
+  PreambleData(const ParseInputs &Inputs, PrecompiledPreamble Preamble,
                std::vector<Diag> Diags, IncludeStructure Includes,
                MainFileMacros Macros,
                std::unique_ptr<PreambleFileStatusCache> StatCache,
@@ -80,7 +80,6 @@
 std::shared_ptr<const PreambleData>
 buildPreamble(PathRef FileName, CompilerInvocation &CI,
               std::shared_ptr<const PreambleData> OldPreamble,
-              const tooling::CompileCommand &OldCompileCommand,
               const ParseInputs &Inputs, bool StoreInMemory,
               PreambleParsedCallback PreambleCallback);
 
diff --git a/clang-tools-extra/clangd/Preamble.cpp b/clang-tools-extra/clangd/Preamble.cpp
--- a/clang-tools-extra/clangd/Preamble.cpp
+++ b/clang-tools-extra/clangd/Preamble.cpp
@@ -7,6 +7,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "Preamble.h"
+#include "Compiler.h"
 #include "Logger.h"
 #include "Trace.h"
 #include "clang/Basic/SourceLocation.h"
@@ -75,13 +76,14 @@
 
 } // namespace
 
-PreambleData::PreambleData(llvm::StringRef Version,
+PreambleData::PreambleData(const ParseInputs &Inputs,
                            PrecompiledPreamble Preamble,
                            std::vector<Diag> Diags, IncludeStructure Includes,
                            MainFileMacros Macros,
                            std::unique_ptr<PreambleFileStatusCache> StatCache,
                            CanonicalIncludes CanonIncludes)
-    : Version(Version), Preamble(std::move(Preamble)), Diags(std::move(Diags)),
+    : Version(Inputs.Version), CompileCommand(Inputs.CompileCommand),
+      Preamble(std::move(Preamble)), Diags(std::move(Diags)),
       Includes(std::move(Includes)), Macros(std::move(Macros)),
       StatCache(std::move(StatCache)), CanonIncludes(std::move(CanonIncludes)) {
 }
@@ -89,7 +91,6 @@
 std::shared_ptr<const PreambleData>
 buildPreamble(PathRef FileName, CompilerInvocation &CI,
               std::shared_ptr<const PreambleData> OldPreamble,
-              const tooling::CompileCommand &OldCompileCommand,
               const ParseInputs &Inputs, bool StoreInMemory,
               PreambleParsedCallback PreambleCallback) {
   // Note that we don't need to copy the input contents, preamble can live
@@ -100,7 +101,8 @@
       ComputePreambleBounds(*CI.getLangOpts(), ContentsBuffer.get(), 0);
 
   if (OldPreamble &&
-      compileCommandsAreEqual(Inputs.CompileCommand, OldCompileCommand) &&
+      compileCommandsAreEqual(Inputs.CompileCommand,
+                              OldPreamble->CompileCommand) &&
       OldPreamble->Preamble.CanReuse(CI, ContentsBuffer.get(), Bounds,
                                      Inputs.FS.get())) {
     vlog("Reusing preamble version {0} for version {1} of {2}",
@@ -155,7 +157,7 @@
          BuiltPreamble->getSize(), FileName, Inputs.Version);
     std::vector<Diag> Diags = PreambleDiagnostics.take();
     return std::make_shared<PreambleData>(
-        Inputs.Version, std::move(*BuiltPreamble), std::move(Diags),
+        Inputs, std::move(*BuiltPreamble), std::move(Diags),
         SerializedDeclsCollector.takeIncludes(),
         SerializedDeclsCollector.takeMacros(), std::move(StatCache),
         SerializedDeclsCollector.takeCanonicalIncludes());
diff --git a/clang-tools-extra/clangd/TUScheduler.cpp b/clang-tools-extra/clangd/TUScheduler.cpp
--- a/clang-tools-extra/clangd/TUScheduler.cpp
+++ b/clang-tools-extra/clangd/TUScheduler.cpp
@@ -403,7 +403,6 @@
         std::tie(PrevInputs->CompileCommand, PrevInputs->Contents) ==
         std::tie(Inputs.CompileCommand, Inputs.Contents);
 
-    tooling::CompileCommand OldCommand = PrevInputs->CompileCommand;
     bool RanCallbackForPrevInputs = RanASTCallback;
     {
       std::lock_guard<std::mutex> Lock(Mutex);
@@ -445,8 +444,7 @@
         Inputs.ForceRebuild ? std::shared_ptr<const PreambleData>()
                             : getPossiblyStalePreamble();
     std::shared_ptr<const PreambleData> NewPreamble = buildPreamble(
-        FileName, *Invocation, OldPreamble, OldCommand, Inputs,
-        StorePreambleInMemory,
+        FileName, *Invocation, OldPreamble, Inputs, StorePreambleInMemory,
         [this, Version(Inputs.Version)](
             ASTContext &Ctx, std::shared_ptr<clang::Preprocessor> PP,
             const CanonicalIncludes &CanonIncludes) {
diff --git a/clang-tools-extra/clangd/unittests/FileIndexTests.cpp b/clang-tools-extra/clangd/unittests/FileIndexTests.cpp
--- a/clang-tools-extra/clangd/unittests/FileIndexTests.cpp
+++ b/clang-tools-extra/clangd/unittests/FileIndexTests.cpp
@@ -286,16 +286,16 @@
 
   FileIndex Index;
   bool IndexUpdated = false;
-  buildPreamble(
-      FooCpp, *CI, /*OldPreamble=*/nullptr, tooling::CompileCommand(), PI,
-      /*StoreInMemory=*/true,
-      [&](ASTContext &Ctx, std::shared_ptr<Preprocessor> PP,
-          const CanonicalIncludes &CanonIncludes) {
-        EXPECT_FALSE(IndexUpdated) << "Expected only a single index update";
-        IndexUpdated = true;
-        Index.updatePreamble(FooCpp, /*Version=*/"null", Ctx, std::move(PP),
-                             CanonIncludes);
-      });
+  buildPreamble(FooCpp, *CI, /*OldPreamble=*/nullptr, PI,
+                /*StoreInMemory=*/true,
+                [&](ASTContext &Ctx, std::shared_ptr<Preprocessor> PP,
+                    const CanonicalIncludes &CanonIncludes) {
+                  EXPECT_FALSE(IndexUpdated)
+                      << "Expected only a single index update";
+                  IndexUpdated = true;
+                  Index.updatePreamble(FooCpp, /*Version=*/"null", Ctx,
+                                       std::move(PP), CanonIncludes);
+                });
   ASSERT_TRUE(IndexUpdated);
 
   // Check the index contains symbols from the preamble, but not from the main
diff --git a/clang-tools-extra/clangd/unittests/TestTU.cpp b/clang-tools-extra/clangd/unittests/TestTU.cpp
--- a/clang-tools-extra/clangd/unittests/TestTU.cpp
+++ b/clang-tools-extra/clangd/unittests/TestTU.cpp
@@ -67,8 +67,7 @@
   assert(CI && "Failed to build compilation invocation.");
   auto Preamble =
       buildPreamble(FullFilename, *CI,
-                    /*OldPreamble=*/nullptr,
-                    /*OldCompileCommand=*/Inputs.CompileCommand, Inputs,
+                    /*OldPreamble=*/nullptr, Inputs,
                     /*StoreInMemory=*/true, /*PreambleCallback=*/nullptr);
   auto AST =
       buildAST(FullFilename, std::move(CI), Diags.take(), Inputs, Preamble);