Refactor traversal of bases in deduction of template parameters from base

classes of an argument to use CXXRecordDecl::forallBases. Fix forallBases to
only visit each base class once.

llvm-svn: 267453

1 files changed, 9 insertions, 6 deletions

diff --git a/clang/lib/AST/CXXInheritance.cpp b/clang/lib/AST/CXXInheritance.cpp
index 6a6ca76a016..d1a2b435df1 100644
--- a/clang/lib/AST/CXXInheritance.cpp
+++ b/clang/lib/AST/CXXInheritance.cpp
@@ -137,6 +137,7 @@ CXXRecordDecl::isCurrentInstantiation(const DeclContext *CurContext) const {
 bool CXXRecordDecl::forallBases(ForallBasesCallback BaseMatches,
                                 bool AllowShortCircuit) const {
   SmallVector<const CXXRecordDecl*, 8> Queue;
+  llvm::SmallPtrSet<const CXXRecordDecl*, 8> Enqueued;
 
   const CXXRecordDecl *Record = this;
   bool AllMatches = true;
@@ -158,12 +159,14 @@ bool CXXRecordDecl::forallBases(ForallBasesCallback BaseMatches,
         AllMatches = false;
         continue;
       }
-      
-      Queue.push_back(Base);
-      if (!BaseMatches(Base)) {
-        if (AllowShortCircuit) return false;
-        AllMatches = false;
-        continue;
+
+      if (Enqueued.insert(Base).second) {
+        Queue.push_back(Base);
+        if (!BaseMatches(Base)) {
+          if (AllowShortCircuit) return false;
+          AllMatches = false;
+          continue;
+        }
       }
     }