Print source filename when invalid debug info is found in LTO.

When invalid debug info is found in a module during LTO, the debug info
from that module is stripped. However, we do not print the source
filename, which makes it impossible to figure out where the invalid
debug info is coming from.

This patch prints the source file name.

Author: rastogishubham

llvm/lib/LTO/LTOCodeGenerator.cpp

@@ -548,6 +548,7 @@ void LTOCodeGenerator::verifyMergedModuleOnce() {
     report_fatal_error("Broken module found, compilation aborted!");
   if (BrokenDebugInfo) {
     emitWarning("Invalid debug info found, debug info will be stripped");
+    emitWarning("Source FileName: " + MergedModule->getSourceFileName());
     StripDebugInfo(*MergedModule);
   }
 }

llvm/lib/LTO/ThinLTOCodeGenerator.cpp

@@ -182,6 +182,8 @@ static void verifyLoadedModule(Module &TheModule) {
   if (BrokenDebugInfo) {
     TheModule.getContext().diagnose(ThinLTODiagnosticInfo(
         "Invalid debug info found, debug info will be stripped", DS_Warning));
+    TheModule.getContext().diagnose(ThinLTODiagnosticInfo(
+        "Source File Name: " + TheModule.getSourceFileName(), DS_Warning));
     StripDebugInfo(TheModule);
   }
 }