diff --git a/clang/lib/Frontend/ASTUnit.cpp b/clang/lib/Frontend/ASTUnit.cpp
index 221bf97c..95d1bf2 100644
--- a/clang/lib/Frontend/ASTUnit.cpp
+++ b/clang/lib/Frontend/ASTUnit.cpp
@@ -1304,22 +1304,22 @@
                             PreambleInvocationIn.getDiagnosticOpts());
       getDiagnostics().setNumWarnings(NumWarningsInPreamble);
 
-      PreambleRebuildCounter = 1;
+      PreambleRebuildCountdown = 1;
       return MainFileBuffer;
     } else {
       Preamble.reset();
       PreambleDiagnostics.clear();
       TopLevelDeclsInPreamble.clear();
       PreambleSrcLocCache.clear();
-      PreambleRebuildCounter = 1;
+      PreambleRebuildCountdown = 1;
     }
   }
 
   // If the preamble rebuild counter > 1, it's because we previously
   // failed to build a preamble and we're not yet ready to try
   // again. Decrement the counter and return a failure.
-  if (PreambleRebuildCounter > 1) {
-    --PreambleRebuildCounter;
+  if (PreambleRebuildCountdown > 1) {
+    --PreambleRebuildCountdown;
     return nullptr;
   }
 
@@ -1329,6 +1329,8 @@
   if (!AllowRebuild)
     return nullptr;
 
+  ++PreambleCounter;
+
   SmallVector<StandaloneDiagnostic, 4> NewPreambleDiagsStandalone;
   SmallVector<StoredDiagnostic, 4> NewPreambleDiags;
   ASTUnitPreambleCallbacks Callbacks;
@@ -1356,18 +1358,18 @@
 
     if (NewPreamble) {
       Preamble = std::move(*NewPreamble);
-      PreambleRebuildCounter = 1;
+      PreambleRebuildCountdown = 1;
     } else {
       switch (static_cast<BuildPreambleError>(NewPreamble.getError().value())) {
       case BuildPreambleError::CouldntCreateTempFile:
         // Try again next time.
-        PreambleRebuildCounter = 1;
+        PreambleRebuildCountdown = 1;
         return nullptr;
       case BuildPreambleError::CouldntCreateTargetInfo:
       case BuildPreambleError::BeginSourceFileFailed:
       case BuildPreambleError::CouldntEmitPCH:
         // These erros are more likely to repeat, retry after some period.
-        PreambleRebuildCounter = DefaultPreambleRebuildInterval;
+        PreambleRebuildCountdown = DefaultPreambleRebuildInterval;
         return nullptr;
       }
       llvm_unreachable("unexpected BuildPreambleError");
@@ -1507,7 +1509,7 @@
   AST->OnlyLocalDecls = OnlyLocalDecls;
   AST->CaptureDiagnostics = CaptureDiagnostics;
   if (PrecompilePreambleAfterNParses > 0)
-    AST->PreambleRebuildCounter = PrecompilePreambleAfterNParses;
+    AST->PreambleRebuildCountdown = PrecompilePreambleAfterNParses;
   AST->TUKind = Action ? Action->getTranslationUnitKind() : TU_Complete;
   AST->ShouldCacheCodeCompletionResults = CacheCodeCompletionResults;
   AST->IncludeBriefCommentsInCodeCompletion
@@ -1641,7 +1643,7 @@
 
   std::unique_ptr<llvm::MemoryBuffer> OverrideMainBuffer;
   if (PrecompilePreambleAfterNParses > 0) {
-    PreambleRebuildCounter = PrecompilePreambleAfterNParses;
+    PreambleRebuildCountdown = PrecompilePreambleAfterNParses;
     OverrideMainBuffer =
         getMainBufferWithPrecompiledPreamble(PCHContainerOps, *Invocation, VFS);
     getDiagnostics().Reset();
@@ -1819,7 +1821,7 @@
   // If we have a preamble file lying around, or if we might try to
   // build a precompiled preamble, do so now.
   std::unique_ptr<llvm::MemoryBuffer> OverrideMainBuffer;
-  if (Preamble || PreambleRebuildCounter > 0)
+  if (Preamble || PreambleRebuildCountdown > 0)
     OverrideMainBuffer =
         getMainBufferWithPrecompiledPreamble(PCHContainerOps, *Invocation, VFS);