r303366 - [index] Avoid one more crash caused by infinite recursion that happens when

[Alex Lorenz via cfe-commits]

Author: arphaman
Date: Thu May 18 13:06:07 2017
New Revision: 303366

URL: http://llvm.org/viewvc/llvm-project?rev=303366&view=rev
Log:
[index] Avoid one more crash caused by infinite recursion that happens when
looking up a dependent name in a record that derives from itself

rdar://32273000

Differential Revision: https://reviews.llvm.org/D33324

Modified:
    cfe/trunk/include/clang/AST/CXXInheritance.h
    cfe/trunk/lib/AST/CXXInheritance.cpp
    cfe/trunk/test/Index/Core/index-dependent-source.cpp

Modified: cfe/trunk/include/clang/AST/CXXInheritance.h
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/AST/CXXInheritance.h?rev=303366&r1=303365&r2=303366&view=diff
==============================================================================
--- cfe/trunk/include/clang/AST/CXXInheritance.h (original)
+++ cfe/trunk/include/clang/AST/CXXInheritance.h Thu May 18 13:06:07 2017
@@ -127,7 +127,11 @@ class CXXBasePaths {
   /// class subobjects for that class type. The key of the map is
   /// the cv-unqualified canonical type of the base class subobject.
   llvm::SmallDenseMap<QualType, std::pair<bool, unsigned>, 8> ClassSubobjects;
-  
+
+  /// VisitedDependentRecords - Records the dependent records that have been
+  /// already visited.
+  llvm::SmallDenseSet<const CXXRecordDecl *, 4> VisitedDependentRecords;
+
   /// FindAmbiguities - Whether Sema::IsDerivedFrom should try find
   /// ambiguous paths while it is looking for a path from a derived
   /// type to a base type.

Modified: cfe/trunk/lib/AST/CXXInheritance.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/AST/CXXInheritance.cpp?rev=303366&r1=303365&r2=303366&view=diff
==============================================================================
--- cfe/trunk/lib/AST/CXXInheritance.cpp (original)
+++ cfe/trunk/lib/AST/CXXInheritance.cpp Thu May 18 13:06:07 2017
@@ -57,6 +57,7 @@ bool CXXBasePaths::isAmbiguous(CanQualTy
 void CXXBasePaths::clear() {
   Paths.clear();
   ClassSubobjects.clear();
+  VisitedDependentRecords.clear();
   ScratchPath.clear();
   DetectedVirtual = nullptr;
 }
@@ -67,6 +68,7 @@ void CXXBasePaths::swap(CXXBasePaths &Ot
   std::swap(Origin, Other.Origin);
   Paths.swap(Other.Paths);
   ClassSubobjects.swap(Other.ClassSubobjects);
+  VisitedDependentRecords.swap(Other.VisitedDependentRecords);
   std::swap(FindAmbiguities, Other.FindAmbiguities);
   std::swap(RecordPaths, Other.RecordPaths);
   std::swap(DetectVirtual, Other.DetectVirtual);
@@ -278,8 +280,14 @@ bool CXXBasePaths::lookupInBases(ASTCont
                   dyn_cast_or_null<ClassTemplateDecl>(TN.getAsTemplateDecl()))
             BaseRecord = TD->getTemplatedDecl();
         }
-        if (BaseRecord && !BaseRecord->hasDefinition())
-          BaseRecord = nullptr;
+        if (BaseRecord) {
+          if (!BaseRecord->hasDefinition() ||
+              VisitedDependentRecords.count(BaseRecord)) {
+            BaseRecord = nullptr;
+          } else {
+            VisitedDependentRecords.insert(BaseRecord);
+          }
+        }
       } else {
         BaseRecord = cast<CXXRecordDecl>(
             BaseSpec.getType()->castAs<RecordType>()->getDecl());

Modified: cfe/trunk/test/Index/Core/index-dependent-source.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Index/Core/index-dependent-source.cpp?rev=303366&r1=303365&r2=303366&view=diff
==============================================================================
--- cfe/trunk/test/Index/Core/index-dependent-source.cpp (original)
+++ cfe/trunk/test/Index/Core/index-dependent-source.cpp Thu May 18 13:06:07 2017
@@ -141,3 +141,20 @@ void undefinedTemplateLookup2(UserOfUnde
   x.lookup;
   typename UserOfUndefinedTemplateClass<T>::Type y;
 }
+
+template<typename T> struct Dropper;
+
+template<typename T> struct Trait;
+
+template<typename T>
+struct Recurse : Trait<typename Dropper<T>::Type> { };
+
+template<typename T>
+struct Trait : Recurse<T> {
+};
+
+template<typename T>
+void infiniteTraitRecursion(Trait<T> &t) {
+// Shouldn't crash!
+  t.lookup;
+}