1 files changed, 44 insertions, 31 deletions

diff --git a/clang/lib/Sema/SemaTemplateInstantiate.cpp b/clang/lib/Sema/SemaTemplateInstantiate.cpp
index 160c9f09078..ba4a5b7bc0d 100644
--- a/clang/lib/Sema/SemaTemplateInstantiate.cpp
+++ b/clang/lib/Sema/SemaTemplateInstantiate.cpp
@@ -2280,16 +2280,18 @@ namespace {
   };
 }
 
-bool Sema::InstantiateClassTemplateSpecialization(
-    SourceLocation PointOfInstantiation,
+/// Get the instantiation pattern to use to instantiate the definition of a
+/// given ClassTemplateSpecializationDecl (either the pattern of the primary
+/// template or of a partial specialization).
+static CXXRecordDecl *
+getPatternForClassTemplateSpecialization(
+    Sema &S, SourceLocation PointOfInstantiation,
     ClassTemplateSpecializationDecl *ClassTemplateSpec,
     TemplateSpecializationKind TSK, bool Complain) {
-  // Perform the actual instantiation on the canonical declaration.
-  ClassTemplateSpec = cast<ClassTemplateSpecializationDecl>(
-                                         ClassTemplateSpec->getCanonicalDecl());
-  if (ClassTemplateSpec->isInvalidDecl())
-    return true;
-  
+  Sema::InstantiatingTemplate Inst(S, PointOfInstantiation, ClassTemplateSpec);
+  if (Inst.isInvalid() || Inst.isAlreadyInstantiating())
+    return nullptr;
+
   ClassTemplateDecl *Template = ClassTemplateSpec->getSpecializedTemplate();
   CXXRecordDecl *Pattern = nullptr;
 
@@ -2309,15 +2311,13 @@ bool Sema::InstantiateClassTemplateSpecialization(
   for (unsigned I = 0, N = PartialSpecs.size(); I != N; ++I) {
     ClassTemplatePartialSpecializationDecl *Partial = PartialSpecs[I];
     TemplateDeductionInfo Info(FailedCandidates.getLocation());
-    if (TemplateDeductionResult Result
-          = DeduceTemplateArguments(Partial,
-                                    ClassTemplateSpec->getTemplateArgs(),
-                                    Info)) {
+    if (Sema::TemplateDeductionResult Result = S.DeduceTemplateArguments(
+            Partial, ClassTemplateSpec->getTemplateArgs(), Info)) {
       // Store the failed-deduction information for use in diagnostics, later.
       // TODO: Actually use the failed-deduction info?
       FailedCandidates.addCandidate().set(
           DeclAccessPair::make(Template, AS_public), Partial,
-          MakeDeductionFailureInfo(Context, Result, Info));
+          MakeDeductionFailureInfo(S.Context, Result, Info));
       (void)Result;
     } else {
       Matched.push_back(PartialSpecMatchResult());
@@ -2347,9 +2347,8 @@ bool Sema::InstantiateClassTemplateSpecialization(
       for (SmallVectorImpl<MatchResult>::iterator P = Best + 1,
                                                PEnd = Matched.end();
            P != PEnd; ++P) {
-        if (getMoreSpecializedPartialSpecialization(P->Partial, Best->Partial,
-                                                    PointOfInstantiation) 
-              == P->Partial)
+        if (S.getMoreSpecializedPartialSpecialization(
+                P->Partial, Best->Partial, PointOfInstantiation) == P->Partial)
           Best = P;
       }
       
@@ -2360,9 +2359,9 @@ bool Sema::InstantiateClassTemplateSpecialization(
                                                PEnd = Matched.end();
            P != PEnd; ++P) {
         if (P != Best &&
-            getMoreSpecializedPartialSpecialization(P->Partial, Best->Partial,
-                                                    PointOfInstantiation)
-              != Best->Partial) {
+            S.getMoreSpecializedPartialSpecialization(P->Partial, Best->Partial,
+                                                      PointOfInstantiation) !=
+                Best->Partial) {
           Ambiguous = true;
           break;
         }
@@ -2370,20 +2369,20 @@ bool Sema::InstantiateClassTemplateSpecialization(
        
       if (Ambiguous) {
         // Partial ordering did not produce a clear winner. Complain.
+        Inst.Clear();
         ClassTemplateSpec->setInvalidDecl();
-        Diag(PointOfInstantiation, diag::err_partial_spec_ordering_ambiguous)
+        S.Diag(PointOfInstantiation, diag::err_partial_spec_ordering_ambiguous)
           << ClassTemplateSpec;
         
         // Print the matching partial specializations.
         for (SmallVectorImpl<MatchResult>::iterator P = Matched.begin(),
                                                  PEnd = Matched.end();
              P != PEnd; ++P)
-          Diag(P->Partial->getLocation(), diag::note_partial_spec_match)
-            << getTemplateArgumentBindingsText(
-                                            P->Partial->getTemplateParameters(),
-                                               *P->Args);
+          S.Diag(P->Partial->getLocation(), diag::note_partial_spec_match)
+            << S.getTemplateArgumentBindingsText(
+                   P->Partial->getTemplateParameters(), *P->Args);
 
-        return true;
+        return nullptr;
       }
     }
     
@@ -2416,13 +2415,27 @@ bool Sema::InstantiateClassTemplateSpecialization(
     Pattern = OrigTemplate->getTemplatedDecl();
   }
 
-  bool Result = InstantiateClass(PointOfInstantiation, ClassTemplateSpec, 
-                                 Pattern,
-                                getTemplateInstantiationArgs(ClassTemplateSpec),
-                                 TSK,
-                                 Complain);
+  return Pattern;
+}
 
-  return Result;
+bool Sema::InstantiateClassTemplateSpecialization(
+    SourceLocation PointOfInstantiation,
+    ClassTemplateSpecializationDecl *ClassTemplateSpec,
+    TemplateSpecializationKind TSK, bool Complain) {
+  // Perform the actual instantiation on the canonical declaration.
+  ClassTemplateSpec = cast<ClassTemplateSpecializationDecl>(
+      ClassTemplateSpec->getCanonicalDecl());
+  if (ClassTemplateSpec->isInvalidDecl())
+    return true;
+
+  CXXRecordDecl *Pattern = getPatternForClassTemplateSpecialization(
+      *this, PointOfInstantiation, ClassTemplateSpec, TSK, Complain);
+  if (!Pattern)
+    return true;
+
+  return InstantiateClass(PointOfInstantiation, ClassTemplateSpec, Pattern,
+                          getTemplateInstantiationArgs(ClassTemplateSpec), TSK,
+                          Complain);
 }
 
 /// \brief Instantiates the definitions of all of the member