[CrossTU] Handle case when no USR could be generated during Decl search.

Summary:
When searching for a declaration to be loaded the "lookup name" for every
other Decl is computed. If the USR can not be determined here should be
not an assert, instead skip this Decl.

Reviewers: martong

Reviewed By: martong

Subscribers: rnkovacs, dkrupp, Szelethus, gamesh411, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D65445

llvm-svn: 368020

1 files changed, 7 insertions, 2 deletions

diff --git a/clang/tools/clang-extdef-mapping/ClangExtDefMapGen.cpp b/clang/tools/clang-extdef-mapping/ClangExtDefMapGen.cpp
index 7a374698f7b..3c015fef93c 100644
--- a/clang/tools/clang-extdef-mapping/ClangExtDefMapGen.cpp
+++ b/clang/tools/clang-extdef-mapping/ClangExtDefMapGen.cpp
@@ -76,7 +76,12 @@ void MapExtDefNamesConsumer::handleDecl(const Decl *D) {
 
 void MapExtDefNamesConsumer::addIfInMain(const DeclaratorDecl *DD,
                                          SourceLocation defStart) {
-  std::string LookupName = CrossTranslationUnitContext::getLookupName(DD);
+  llvm::Optional<std::string> LookupName =
+      CrossTranslationUnitContext::getLookupName(DD);
+  if (!LookupName)
+    return;
+  assert(!LookupName->empty() && "Lookup name should be non-empty.");
+
   if (CurrentFileName.empty()) {
     CurrentFileName =
         SM.getFileEntryForID(SM.getMainFileID())->tryGetRealPathName();
@@ -89,7 +94,7 @@ void MapExtDefNamesConsumer::addIfInMain(const DeclaratorDecl *DD,
   case VisibleNoLinkage:
   case UniqueExternalLinkage:
     if (SM.isInMainFile(defStart))
-      Index[LookupName] = CurrentFileName;
+      Index[*LookupName] = CurrentFileName;
     break;
   default:
     break;