[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, 11 insertions, 9 deletions

diff --git a/clang/lib/CrossTU/CrossTranslationUnit.cpp b/clang/lib/CrossTU/CrossTranslationUnit.cpp
index f43180a2a27..bd8a022eb4d 100644
--- a/clang/lib/CrossTU/CrossTranslationUnit.cpp
+++ b/clang/lib/CrossTU/CrossTranslationUnit.cpp
@@ -193,12 +193,13 @@ CrossTranslationUnitContext::CrossTranslationUnitContext(CompilerInstance &CI)
 
 CrossTranslationUnitContext::~CrossTranslationUnitContext() {}
 
-std::string CrossTranslationUnitContext::getLookupName(const NamedDecl *ND) {
+llvm::Optional<std::string>
+CrossTranslationUnitContext::getLookupName(const NamedDecl *ND) {
   SmallString<128> DeclUSR;
   bool Ret = index::generateUSRForDecl(ND, DeclUSR);
-  (void)Ret;
-  assert(!Ret && "Unable to generate USR");
-  return DeclUSR.str();
+  if (Ret)
+    return {};
+  return std::string(DeclUSR.str());
 }
 
 /// Recursively visits the decls of a DeclContext, and returns one with the
@@ -218,7 +219,8 @@ CrossTranslationUnitContext::findDefInDeclContext(const DeclContext *DC,
     const T *ResultDecl;
     if (!ND || !hasBodyOrInit(ND, ResultDecl))
       continue;
-    if (getLookupName(ResultDecl) != LookupName)
+    llvm::Optional<std::string> ResultLookupName = getLookupName(ResultDecl);
+    if (!ResultLookupName || *ResultLookupName != LookupName)
       continue;
     return ResultDecl;
   }
@@ -233,12 +235,12 @@ llvm::Expected<const T *> CrossTranslationUnitContext::getCrossTUDefinitionImpl(
   assert(!hasBodyOrInit(D) &&
          "D has a body or init in current translation unit!");
   ++NumGetCTUCalled;
-  const std::string LookupName = getLookupName(D);
-  if (LookupName.empty())
+  const llvm::Optional<std::string> LookupName = getLookupName(D);
+  if (!LookupName)
     return llvm::make_error<IndexError>(
         index_error_code::failed_to_generate_usr);
   llvm::Expected<ASTUnit *> ASTUnitOrError =
-      loadExternalAST(LookupName, CrossTUDir, IndexName, DisplayCTUProgress);
+      loadExternalAST(*LookupName, CrossTUDir, IndexName, DisplayCTUProgress);
   if (!ASTUnitOrError)
     return ASTUnitOrError.takeError();
   ASTUnit *Unit = *ASTUnitOrError;
@@ -294,7 +296,7 @@ llvm::Expected<const T *> CrossTranslationUnitContext::getCrossTUDefinitionImpl(
   }
 
   TranslationUnitDecl *TU = Unit->getASTContext().getTranslationUnitDecl();
-  if (const T *ResultDecl = findDefInDeclContext<T>(TU, LookupName))
+  if (const T *ResultDecl = findDefInDeclContext<T>(TU, *LookupName))
     return importDefinition(ResultDecl, Unit);
   return llvm::make_error<IndexError>(index_error_code::failed_import);
 }