Index: include/clang/CrossTU/CrossTranslationUnit.h
===================================================================
--- include/clang/CrossTU/CrossTranslationUnit.h
+++ include/clang/CrossTU/CrossTranslationUnit.h
@@ -108,7 +108,7 @@
   /// Note that the AST files should also be in the \p CrossTUDir.
   llvm::Expected<const FunctionDecl *>
   getCrossTUDefinition(const FunctionDecl *FD, StringRef CrossTUDir,
-                       StringRef IndexName);
+                       StringRef IndexName, bool DisplayCTUProgress = false);
 
   /// This function loads a function definition from an external AST
   ///        file.
@@ -124,7 +124,8 @@
   /// Note that the AST files should also be in the \p CrossTUDir.
   llvm::Expected<ASTUnit *> loadExternalAST(StringRef LookupName,
                                             StringRef CrossTUDir,
-                                            StringRef IndexName);
+                                            StringRef IndexName,
+                                            bool DisplayCTUProgress = false);
 
   /// This function merges a definition from a separate AST Unit into
   ///        the current one which was created by the compiler instance that
Index: include/clang/StaticAnalyzer/Core/AnalyzerOptions.def
===================================================================
--- include/clang/StaticAnalyzer/Core/AnalyzerOptions.def
+++ include/clang/StaticAnalyzer/Core/AnalyzerOptions.def
@@ -283,6 +283,11 @@
                 "expanded and included in the plist output.",
                 false)
 
+ANALYZER_OPTION(bool, DisplayCTUProgress, "display-ctu-progress",
+                "Whether to emit verbose output about "
+                "the analyzer's progress related to ctu.",
+                false)
+
 //===----------------------------------------------------------------------===//
 // Unsinged analyzer options.
 //===----------------------------------------------------------------------===//
Index: lib/CrossTU/CrossTranslationUnit.cpp
===================================================================
--- lib/CrossTU/CrossTranslationUnit.cpp
+++ lib/CrossTU/CrossTranslationUnit.cpp
@@ -149,14 +149,15 @@
 llvm::Expected<const FunctionDecl *>
 CrossTranslationUnitContext::getCrossTUDefinition(const FunctionDecl *FD,
                                                   StringRef CrossTUDir,
-                                                  StringRef IndexName) {
+                                                  StringRef IndexName,
+                                                  bool DisplayCTUProgress) {
   assert(!FD->hasBody() && "FD has a definition in current translation unit!");
   const std::string LookupFnName = getLookupName(FD);
   if (LookupFnName.empty())
     return llvm::make_error<IndexError>(
         index_error_code::failed_to_generate_usr);
   llvm::Expected<ASTUnit *> ASTUnitOrError =
-      loadExternalAST(LookupFnName, CrossTUDir, IndexName);
+      loadExternalAST(LookupFnName, CrossTUDir, IndexName, DisplayCTUProgress);
   if (!ASTUnitOrError)
     return ASTUnitOrError.takeError();
   ASTUnit *Unit = *ASTUnitOrError;
@@ -193,7 +194,8 @@
 }
 
 llvm::Expected<ASTUnit *> CrossTranslationUnitContext::loadExternalAST(
-    StringRef LookupName, StringRef CrossTUDir, StringRef IndexName) {
+    StringRef LookupName, StringRef CrossTUDir, StringRef IndexName,
+    bool DisplayCTUProgress) {
   // FIXME: The current implementation only supports loading functions with
   //        a lookup name from a single translation unit. If multiple
   //        translation units contains functions with the same lookup name an
@@ -233,6 +235,10 @@
           ASTUnit::LoadEverything, Diags, CI.getFileSystemOpts()));
       Unit = LoadedUnit.get();
       FileASTUnitMap[ASTFileName] = std::move(LoadedUnit);
+      if (DisplayCTUProgress) {
+        llvm::errs() << "CTU loaded AST file: "
+                     << ASTFileName << "\n";
+      }
     } else {
       Unit = ASTCacheEntry->second.get();
     }
Index: lib/StaticAnalyzer/Core/CallEvent.cpp
===================================================================
--- lib/StaticAnalyzer/Core/CallEvent.cpp
+++ lib/StaticAnalyzer/Core/CallEvent.cpp
@@ -560,8 +560,8 @@
   cross_tu::CrossTranslationUnitContext &CTUCtx =
       *Engine->getCrossTranslationUnitContext();
   llvm::Expected<const FunctionDecl *> CTUDeclOrError =
-      CTUCtx.getCrossTUDefinition(FD, Opts.CTUDir,
-                                  Opts.CTUIndexName);
+      CTUCtx.getCrossTUDefinition(FD, Opts.CTUDir, Opts.CTUIndexName,
+                                  Opts.DisplayCTUProgress);
 
   if (!CTUDeclOrError) {
     handleAllErrors(CTUDeclOrError.takeError(),
Index: test/Analysis/analyzer-config.c
===================================================================
--- test/Analysis/analyzer-config.c
+++ test/Analysis/analyzer-config.c
@@ -21,6 +21,7 @@
 // CHECK-NEXT: crosscheck-with-z3 = false
 // CHECK-NEXT: ctu-dir = ""
 // CHECK-NEXT: ctu-index-name = externalFnMap.txt
+// CHECK-NEXT: display-ctu-progress = false
 // CHECK-NEXT: eagerly-assume = true
 // CHECK-NEXT: elide-constructors = true
 // CHECK-NEXT: expand-macros = false
@@ -51,4 +52,4 @@
 // CHECK-NEXT: unroll-loops = false
 // CHECK-NEXT: widen-loops = false
 // CHECK-NEXT: [stats]
-// CHECK-NEXT: num-entries = 48
+// CHECK-NEXT: num-entries = 49
Index: test/Analysis/ctu-main.cpp
===================================================================
--- test/Analysis/ctu-main.cpp
+++ test/Analysis/ctu-main.cpp
@@ -3,6 +3,14 @@
 // RUN: %clang_cc1 -triple x86_64-pc-linux-gnu -emit-pch -o %T/ctudir/ctu-chain.cpp.ast %S/Inputs/ctu-chain.cpp
 // RUN: cp %S/Inputs/externalFnMap.txt %T/ctudir/
 // RUN: %clang_cc1 -triple x86_64-pc-linux-gnu -fsyntax-only -analyze -analyzer-checker=core,debug.ExprInspection -analyzer-config experimental-enable-naive-ctu-analysis=true -analyzer-config ctu-dir=%T/ctudir -verify %s
+// RUN: %clang_analyze_cc1 -triple x86_64-pc-linux-gnu \
+// RUN:   -analyzer-checker=core,debug.ExprInspection \
+// RUN:   -analyzer-config experimental-enable-naive-ctu-analysis=true \
+// RUN:   -analyzer-config ctu-dir=%T/ctudir \
+// RUN:   -analyzer-config display-ctu-progress=true 2>&1 %s | FileCheck %s
+
+// CHECK: ANALYZE CTU loaded AST file: {{.*}}/ctu-other.cpp
+// CHECK: ANALYZE CTU loaded AST file: {{.*}}/ctu-chain.cpp
 
 #include "ctu-hdr.h"