r357100 - [ASTImporter] Fix IsStructuralMatch specialization for EnumDecl to prevent re-importing an EnumDecl while trying to complete it

[Shafik Yaghmour via cfe-commits]

Author: shafik
Date: Wed Mar 27 10:47:36 2019
New Revision: 357100

URL: http://llvm.org/viewvc/llvm-project?rev=357100&view=rev
Log:
[ASTImporter] Fix IsStructuralMatch specialization for EnumDecl to prevent re-importing an EnumDecl while trying to complete it

Summary:
We may try and re-import an EnumDecl while trying to complete it in IsStructuralMatch(...) specialization for EnumDecl. This change mirrors a similar fix for the specialization for RecordDecl.

Differential Revision: https://reviews.llvm.org/D59845

Modified:
    cfe/trunk/lib/AST/ASTImporter.cpp

Modified: cfe/trunk/lib/AST/ASTImporter.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/AST/ASTImporter.cpp?rev=357100&r1=357099&r2=357100&view=diff
==============================================================================
--- cfe/trunk/lib/AST/ASTImporter.cpp (original)
+++ cfe/trunk/lib/AST/ASTImporter.cpp Wed Mar 27 10:47:36 2019
@@ -1946,6 +1946,12 @@ bool ASTNodeImporter::IsStructuralMatch(
 }
 
 bool ASTNodeImporter::IsStructuralMatch(EnumDecl *FromEnum, EnumDecl *ToEnum) {
+  // Eliminate a potential failure point where we attempt to re-import
+  // something we're trying to import while completin ToEnum
+  if (Decl *ToOrigin = Importer.GetOriginalDecl(ToEnum))
+    if (auto *ToOriginEnum = dyn_cast<EnumDecl>(ToOrigin))
+        ToEnum = ToOriginEnum;
+
   StructuralEquivalenceContext Ctx(
       Importer.getFromContext(), Importer.getToContext(),
       Importer.getNonEquivalentDecls(), getStructuralEquivalenceKind(Importer));