diff --git a/clang/include/clang/StaticAnalyzer/Checkers/Checkers.td b/clang/include/clang/StaticAnalyzer/Checkers/Checkers.td
--- a/clang/include/clang/StaticAnalyzer/Checkers/Checkers.td
+++ b/clang/include/clang/StaticAnalyzer/Checkers/Checkers.td
@@ -293,6 +293,13 @@
 
 def StdCLibraryFunctionsChecker : Checker<"StdCLibraryFunctions">,
   HelpText<"Improve modeling of the C standard library functions">,
+  CheckerOptions<[
+    CmdLineOption<Boolean,
+                  "DisplayLoadedSummaries",
+                  "If set to true, the checker displays all loaded summaries.",
+                  "false",
+                  Released>
+  ]>,
   Documentation<NotDocumented>;
 
 def StdCLibraryFunctionArgsChecker : Checker<"StdCLibraryFunctionArgs">,
diff --git a/clang/lib/StaticAnalyzer/Checkers/StdLibraryFunctionsChecker.cpp b/clang/lib/StaticAnalyzer/Checkers/StdLibraryFunctionsChecker.cpp
--- a/clang/lib/StaticAnalyzer/Checkers/StdLibraryFunctionsChecker.cpp
+++ b/clang/lib/StaticAnalyzer/Checkers/StdLibraryFunctionsChecker.cpp
@@ -300,6 +300,8 @@
   DefaultBool ChecksEnabled[CK_NumCheckKinds];
   CheckerNameRef CheckNames[CK_NumCheckKinds];
 
+  bool DisplayLoadedSummaries = false;
+
 private:
   Optional<Summary> findFunctionSummary(const FunctionDecl *FD,
                                         CheckerContext &C) const;
@@ -639,8 +641,11 @@
   struct AddToFunctionSummaryMap {
     const ASTContext &ACtx;
     FunctionSummaryMapType &Map;
-    AddToFunctionSummaryMap(const ASTContext &ACtx, FunctionSummaryMapType &FSM)
-        : ACtx(ACtx), Map(FSM) {}
+    bool DisplayLoadedSummaries;
+    AddToFunctionSummaryMap(const ASTContext &ACtx, FunctionSummaryMapType &FSM,
+                            bool DisplayLoadedSummaries)
+        : ACtx(ACtx), Map(FSM), DisplayLoadedSummaries(DisplayLoadedSummaries) {
+    }
     // Add a summary to a FunctionDecl found by lookup. The lookup is performed
     // by the given Name, and in the global scope. The summary will be attached
     // to the found FunctionDecl only if the signatures match.
@@ -655,6 +660,8 @@
             auto Res = Map.insert({FD->getCanonicalDecl(), S});
             assert(Res.second && "Function already has a summary set!");
             (void)Res;
+            if (DisplayLoadedSummaries)
+              llvm::errs() << "Loaded summary for " << Name << "\n";
             return;
           }
         }
@@ -665,7 +672,7 @@
       for (const Summary &S : Summaries)
         operator()(Name, S);
     }
-  } addToFunctionSummaryMap(ACtx, FunctionSummaryMap);
+  } addToFunctionSummaryMap(ACtx, FunctionSummaryMap, DisplayLoadedSummaries);
 
   // We are finally ready to define specifications for all supported functions.
   //
@@ -937,7 +944,10 @@
 }
 
 void ento::registerStdCLibraryFunctionsChecker(CheckerManager &mgr) {
-  mgr.registerChecker<StdLibraryFunctionsChecker>();
+  auto *Checker = mgr.registerChecker<StdLibraryFunctionsChecker>();
+  Checker->DisplayLoadedSummaries =
+      mgr.getAnalyzerOptions().getCheckerBooleanOption(
+          Checker, "DisplayLoadedSummaries");
 }
 
 bool ento::shouldRegisterStdCLibraryFunctionsChecker(const CheckerManager &mgr) {
diff --git a/clang/test/Analysis/analyzer-config.c b/clang/test/Analysis/analyzer-config.c
--- a/clang/test/Analysis/analyzer-config.c
+++ b/clang/test/Analysis/analyzer-config.c
@@ -11,6 +11,7 @@
 // CHECK-NEXT: alpha.security.MmapWriteExec:MmapProtExec = 0x04
 // CHECK-NEXT: alpha.security.MmapWriteExec:MmapProtRead = 0x01
 // CHECK-NEXT: alpha.security.taint.TaintPropagation:Config = ""
+// CHECK-NEXT: apiModeling.StdCLibraryFunctions:DisplayLoadedSummaries = false
 // CHECK-NEXT: apply-fixits = false
 // CHECK-NEXT: avoid-suppressing-null-argument-paths = false
 // CHECK-NEXT: c++-allocator-inlining = true
@@ -106,4 +107,4 @@
 // CHECK-NEXT: unroll-loops = false
 // CHECK-NEXT: widen-loops = false
 // CHECK-NEXT: [stats]
-// CHECK-NEXT: num-entries = 103
+// CHECK-NEXT: num-entries = 104
diff --git a/clang/test/Analysis/std-c-library-functions-arg-constraints.c b/clang/test/Analysis/std-c-library-functions-arg-constraints.c
--- a/clang/test/Analysis/std-c-library-functions-arg-constraints.c
+++ b/clang/test/Analysis/std-c-library-functions-arg-constraints.c
@@ -3,6 +3,7 @@
 // RUN:   -analyzer-checker=core \
 // RUN:   -analyzer-checker=apiModeling.StdCLibraryFunctions \
 // RUN:   -analyzer-checker=apiModeling.StdCLibraryFunctionArgs \
+// RUN:   -analyzer-config apiModeling.StdCLibraryFunctions:DisplayLoadedSummaries=true \
 // RUN:   -analyzer-checker=debug.StdCLibraryFunctionsTester \
 // RUN:   -analyzer-checker=debug.ExprInspection \
 // RUN:   -triple x86_64-unknown-linux-gnu \
@@ -13,6 +14,7 @@
 // RUN:   -analyzer-checker=core \
 // RUN:   -analyzer-checker=apiModeling.StdCLibraryFunctions \
 // RUN:   -analyzer-checker=apiModeling.StdCLibraryFunctionArgs \
+// RUN:   -analyzer-config apiModeling.StdCLibraryFunctions:DisplayLoadedSummaries=true \
 // RUN:   -analyzer-checker=debug.StdCLibraryFunctionsTester \
 // RUN:   -analyzer-checker=debug.ExprInspection \
 // RUN:   -triple x86_64-unknown-linux-gnu \
diff --git a/clang/test/Analysis/std-c-library-functions-arg-constraints.cpp b/clang/test/Analysis/std-c-library-functions-arg-constraints.cpp
--- a/clang/test/Analysis/std-c-library-functions-arg-constraints.cpp
+++ b/clang/test/Analysis/std-c-library-functions-arg-constraints.cpp
@@ -2,6 +2,7 @@
 // RUN:   -analyzer-checker=core \
 // RUN:   -analyzer-checker=apiModeling.StdCLibraryFunctions \
 // RUN:   -analyzer-checker=apiModeling.StdCLibraryFunctionArgs \
+// RUN:   -analyzer-config apiModeling.StdCLibraryFunctions:DisplayLoadedSummaries=true \
 // RUN:   -analyzer-checker=debug.StdCLibraryFunctionsTester \
 // RUN:   -analyzer-checker=debug.ExprInspection \
 // RUN:   -analyzer-config eagerly-assume=false \
diff --git a/clang/test/Analysis/std-c-library-functions.c b/clang/test/Analysis/std-c-library-functions.c
--- a/clang/test/Analysis/std-c-library-functions.c
+++ b/clang/test/Analysis/std-c-library-functions.c
@@ -1,6 +1,7 @@
 // RUN: %clang_analyze_cc1 %s \
 // RUN:   -analyzer-checker=core \
 // RUN:   -analyzer-checker=apiModeling.StdCLibraryFunctions \
+// RUN:   -analyzer-config apiModeling.StdCLibraryFunctions:DisplayLoadedSummaries=true \
 // RUN:   -analyzer-checker=debug.ExprInspection \
 // RUN:   -analyzer-config eagerly-assume=false \
 // RUN:   -triple i686-unknown-linux \
@@ -9,6 +10,7 @@
 // RUN: %clang_analyze_cc1 %s \
 // RUN:   -analyzer-checker=core \
 // RUN:   -analyzer-checker=apiModeling.StdCLibraryFunctions \
+// RUN:   -analyzer-config apiModeling.StdCLibraryFunctions:DisplayLoadedSummaries=true \
 // RUN:   -analyzer-checker=debug.ExprInspection \
 // RUN:   -analyzer-config eagerly-assume=false \
 // RUN:   -triple x86_64-unknown-linux \
@@ -17,6 +19,7 @@
 // RUN: %clang_analyze_cc1 %s \
 // RUN:   -analyzer-checker=core \
 // RUN:   -analyzer-checker=apiModeling.StdCLibraryFunctions \
+// RUN:   -analyzer-config apiModeling.StdCLibraryFunctions:DisplayLoadedSummaries=true \
 // RUN:   -analyzer-checker=debug.ExprInspection \
 // RUN:   -analyzer-config eagerly-assume=false \
 // RUN:   -triple armv7-a15-linux \
@@ -25,6 +28,7 @@
 // RUN: %clang_analyze_cc1 %s \
 // RUN:   -analyzer-checker=core \
 // RUN:   -analyzer-checker=apiModeling.StdCLibraryFunctions \
+// RUN:   -analyzer-config apiModeling.StdCLibraryFunctions:DisplayLoadedSummaries=true \
 // RUN:   -analyzer-checker=debug.ExprInspection \
 // RUN:   -analyzer-config eagerly-assume=false \
 // RUN:   -triple thumbv7-a15-linux \