diff --git a/test/DebugInfo/DumpDeclFromMangledName.swift b/test/DebugInfo/DumpDeclFromMangledName.swift
index 154afd3290f..4b8bcef646b 100644
--- a/test/DebugInfo/DumpDeclFromMangledName.swift
+++ b/test/DebugInfo/DumpDeclFromMangledName.swift
@@ -7,6 +7,22 @@
 // RUN: sed -ne '/--->/s/^.*---> *//p' < %S/Inputs/decl-reconstr-names.txt > %t.check
 
 // RUN: %target-build-swift -emit-executable %s -g -o %t/DeclReconstr -emit-module
+
+// Input validation tests.
+// RUN: not %lldb-moduleimport-test patatino 2>&1 | %FileCheck %s \
+// RUN:   --check-prefix=INVALID-INPUT
+// INVALID-INPUT: patatino does not exists, exiting.
+
+// RUN: not %lldb-moduleimport-test %t/DeclReconstr \
+// RUN:   --decl-from-mangled=patatino 2>&1 | \
+// RUN:   %FileCheck %s --check-prefix=INVALID-DECL
+// INVALID-DECL: patatino does not exists, exiting.
+
+// RUN: not %lldb-moduleimport-test %t/DeclReconstr \
+// RUN:   --type-from-mangled=patatino 2>&1 | \
+// RUN:   %FileCheck %s --check-prefix=INVALID-TYPE
+// INVALID-TYPE: patatino does not exists, exiting.
+
 // RUN: %lldb-moduleimport-test %t/DeclReconstr \
 // RUN:   -decl-from-mangled=%t.input > %t.output 2>&1
 // RUN: diff %t.check %t.output
diff --git a/tools/lldb-moduleimport-test/lldb-moduleimport-test.cpp b/tools/lldb-moduleimport-test/lldb-moduleimport-test.cpp
index 140bedbd4f5..1ac528d57bc 100644
--- a/tools/lldb-moduleimport-test/lldb-moduleimport-test.cpp
+++ b/tools/lldb-moduleimport-test/lldb-moduleimport-test.cpp
@@ -199,6 +199,28 @@ int main(int argc, char **argv) {
   DumpTypeFromMangled.removeArgument();
   InputNames.removeArgument();
 
+  auto validateInputFile = [](std::string Filename) {
+    if (Filename.empty())
+      return true;
+    if (!llvm::sys::fs::exists(llvm::Twine(Filename))) {
+      llvm::errs() << Filename << " does not exists, exiting.\n";
+      return false;
+    }
+    if (!llvm::sys::fs::is_regular_file(llvm::Twine(Filename))) {
+      llvm::errs() << Filename << " is not a regular file, exiting.\n";
+      return false;
+    }
+    return true;
+  };
+
+  for (auto &InputFilename : InputNames)
+    if (!validateInputFile(InputFilename))
+      return 1;
+  if (!validateInputFile(DumpTypeFromMangled))
+    return 1;
+  if (!validateInputFile(DumpDeclFromMangled))
+    return 1;
+
   // Fetch the serialized module bitstreams from the Mach-O files and
   // register them with the module loader.
   llvm::SmallVector<std::pair<char *, uint64_t>, 8> Modules;