Implement pack expansions whose pattern is a base-specifier.

llvm-svn: 122782

12 files changed, 160 insertions, 20 deletions

diff --git a/clang/include/clang/AST/DeclCXX.h b/clang/include/clang/AST/DeclCXX.h
index 79832a41181..0c3d27b86a6 100644
--- a/clang/include/clang/AST/DeclCXX.h
+++ b/clang/include/clang/AST/DeclCXX.h
@@ -168,6 +168,10 @@ class CXXBaseSpecifier {
   /// specifier (if present).
   SourceRange Range;
 
+  /// \brief The source location of the ellipsis, if this is a pack
+  /// expansion.
+  SourceLocation EllipsisLoc;
+  
   /// Virtual - Whether this is a virtual base class or not.
   bool Virtual : 1;
 
@@ -192,8 +196,9 @@ public:
   CXXBaseSpecifier() { }
 
   CXXBaseSpecifier(SourceRange R, bool V, bool BC, AccessSpecifier A,
-                   TypeSourceInfo *TInfo)
-    : Range(R), Virtual(V), BaseOfClass(BC), Access(A), BaseTypeInfo(TInfo) { }
+                   TypeSourceInfo *TInfo, SourceLocation EllipsisLoc)
+    : Range(R), EllipsisLoc(EllipsisLoc), Virtual(V), BaseOfClass(BC), 
+      Access(A), BaseTypeInfo(TInfo) { }
 
   /// getSourceRange - Retrieves the source range that contains the
   /// entire base specifier.
@@ -207,6 +212,14 @@ public:
   /// with the 'class' keyword (vs. one declared with the 'struct' keyword).
   bool isBaseOfClass() const { return BaseOfClass; }
   
+  /// \brief Determine whether this base specifier is a pack expansion.
+  bool isPackExpansion() const { return EllipsisLoc.isValid(); }
+  
+  /// \brief For a pack expansion, determine the location of the ellipsis.
+  SourceLocation getEllipsisLoc() const {
+    return EllipsisLoc;
+  }
+  
   /// getAccessSpecifier - Returns the access specifier for this base
   /// specifier. This is the actual base specifier as used for
   /// semantic analysis, so the result can never be AS_none. To
diff --git a/clang/include/clang/Sema/Sema.h b/clang/include/clang/Sema/Sema.h
index b5dfe0a480c..fda0cf2c312 100644
--- a/clang/include/clang/Sema/Sema.h
+++ b/clang/include/clang/Sema/Sema.h
@@ -127,6 +127,7 @@ namespace clang {
   class TemplateTemplateParmDecl;
   class Token;
   class TypedefDecl;
+  class TypeLoc;
   class UnqualifiedId;
   class UnresolvedLookupExpr;
   class UnresolvedMemberExpr;
@@ -2653,13 +2654,15 @@ public:
   CXXBaseSpecifier *CheckBaseSpecifier(CXXRecordDecl *Class,
                                        SourceRange SpecifierRange,
                                        bool Virtual, AccessSpecifier Access,
-                                       TypeSourceInfo *TInfo);
+                                       TypeSourceInfo *TInfo,
+                                       SourceLocation EllipsisLoc);
 
   BaseResult ActOnBaseSpecifier(Decl *classdecl,
                                 SourceRange SpecifierRange,
                                 bool Virtual, AccessSpecifier Access,
-                                ParsedType basetype, SourceLocation
-                                BaseLoc);
+                                ParsedType basetype, 
+                                SourceLocation BaseLoc,
+                                SourceLocation EllipsisLoc);
 
   bool AttachBaseSpecifiers(CXXRecordDecl *Class, CXXBaseSpecifier **Bases,
                             unsigned NumBases);
@@ -3273,11 +3276,19 @@ public:
   /// \brief Collect the set of unexpanded parameter packs within the given
   /// type.  
   ///
-  /// \param Arg The template argument that will be traversed to find
+  /// \param T The type that will be traversed to find
   /// unexpanded parameter packs.
   void collectUnexpandedParameterPacks(QualType T,
                    llvm::SmallVectorImpl<UnexpandedParameterPack> &Unexpanded);
 
+  /// \brief Collect the set of unexpanded parameter packs within the given
+  /// type.  
+  ///
+  /// \param TL The type that will be traversed to find
+  /// unexpanded parameter packs.
+  void collectUnexpandedParameterPacks(TypeLoc TL,
+                   llvm::SmallVectorImpl<UnexpandedParameterPack> &Unexpanded);
+
   /// \brief Invoked when parsing a template argument followed by an
   /// ellipsis, which creates a pack expansion.
   ///
diff --git a/clang/lib/AST/ASTImporter.cpp b/clang/lib/AST/ASTImporter.cpp
index 08c1ea45f74..c62225ef407 100644
--- a/clang/lib/AST/ASTImporter.cpp
+++ b/clang/lib/AST/ASTImporter.cpp
@@ -1709,6 +1709,10 @@ bool ASTNodeImporter::ImportDefinition(RecordDecl *From, RecordDecl *To) {
       QualType T = Importer.Import(Base1->getType());
       if (T.isNull())
         return true;
+
+      SourceLocation EllipsisLoc;
+      if (Base1->isPackExpansion())
+        EllipsisLoc = Importer.Import(Base1->getEllipsisLoc());
       
       Bases.push_back(
                     new (Importer.getToContext()) 
@@ -1716,7 +1720,8 @@ bool ASTNodeImporter::ImportDefinition(RecordDecl *From, RecordDecl *To) {
                                        Base1->isVirtual(),
                                        Base1->isBaseOfClass(),
                                        Base1->getAccessSpecifierAsWritten(),
-                                       Importer.Import(Base1->getTypeSourceInfo())));
+                                   Importer.Import(Base1->getTypeSourceInfo()),
+                                       EllipsisLoc));
     }
     if (!Bases.empty())
       ToCXX->setBases(Bases.data(), Bases.size());
diff --git a/clang/lib/AST/DeclCXX.cpp b/clang/lib/AST/DeclCXX.cpp
index 35c89971eae..3304ad9a293 100644
--- a/clang/lib/AST/DeclCXX.cpp
+++ b/clang/lib/AST/DeclCXX.cpp
@@ -196,7 +196,8 @@ CXXRecordDecl::setBases(CXXBaseSpecifier const * const *Bases,
     data().getVBases()[I] =
       CXXBaseSpecifier(VBaseClassDecl->getSourceRange(), true,
                        VBaseClassDecl->getTagKind() == TTK_Class,
-                       VBases[I]->getAccessSpecifier(), VBaseTypeInfo);
+                       VBases[I]->getAccessSpecifier(), VBaseTypeInfo,
+                       SourceLocation());
   }
 }
 
diff --git a/clang/lib/CodeGen/Mangle.cpp b/clang/lib/CodeGen/Mangle.cpp
index 0aa9f402f96..834ef4e5693 100644
--- a/clang/lib/CodeGen/Mangle.cpp
+++ b/clang/lib/CodeGen/Mangle.cpp
@@ -2137,8 +2137,9 @@ void CXXNameMangler::mangleTemplateArg(const NamedDecl *P,
   //                ::= I <template-arg>* E # argument pack
   //                ::= sp <expression>     # pack expansion of (C++0x)
   switch (A.getKind()) {
-  default:
-    assert(0 && "Unknown template argument kind!");
+  case TemplateArgument::Null:
+    llvm_unreachable("Cannot mangle NULL template argument");
+      
   case TemplateArgument::Type:
     mangleType(A.getAsType());
     break;
@@ -2187,6 +2188,16 @@ void CXXNameMangler::mangleTemplateArg(const NamedDecl *P,
 
     break;
   }
+      
+  case TemplateArgument::Pack: {
+    // Note: proposal by Mike Herrick on 12/20/10
+    Out << 'J';
+    for (TemplateArgument::pack_iterator PA = A.pack_begin(), 
+                                      PAEnd = A.pack_end();
+         PA != PAEnd; ++PA)
+      mangleTemplateArg(P, *PA);
+    Out << 'E';
+  }
   }
 }
 
diff --git a/clang/lib/Parse/ParseDeclCXX.cpp b/clang/lib/Parse/ParseDeclCXX.cpp
index fe2390f1aa0..adbecdc4a94 100644
--- a/clang/lib/Parse/ParseDeclCXX.cpp
+++ b/clang/lib/Parse/ParseDeclCXX.cpp
@@ -1196,13 +1196,20 @@ Parser::BaseResult Parser::ParseBaseSpecifier(Decl *ClassDecl) {
   if (BaseType.isInvalid())
     return true;
 
+  // Parse the optional ellipsis (for a pack expansion). The ellipsis is 
+  // actually part of the base-specifier-list grammar productions, but we
+  // parse it here for convenience.
+  SourceLocation EllipsisLoc;
+  if (Tok.is(tok::ellipsis))
+    EllipsisLoc = ConsumeToken();
+  
   // Find the complete source range for the base-specifier.
   SourceRange Range(StartLoc, EndLocation);
 
   // Notify semantic analysis that we have parsed a complete
   // base-specifier.
   return Actions.ActOnBaseSpecifier(ClassDecl, Range, IsVirtual, Access,
-                                    BaseType.get(), BaseLoc);
+                                    BaseType.get(), BaseLoc, EllipsisLoc);
 }
 
 /// getAccessSpecifierIfPresent - Determine whether the next token is
diff --git a/clang/lib/Sema/SemaDeclCXX.cpp b/clang/lib/Sema/SemaDeclCXX.cpp
index 0021c798235..10d04fa9a31 100644
--- a/clang/lib/Sema/SemaDeclCXX.cpp
+++ b/clang/lib/Sema/SemaDeclCXX.cpp
@@ -464,7 +464,8 @@ CXXBaseSpecifier *
 Sema::CheckBaseSpecifier(CXXRecordDecl *Class,
                          SourceRange SpecifierRange,
                          bool Virtual, AccessSpecifier Access,
-                         TypeSourceInfo *TInfo) {
+                         TypeSourceInfo *TInfo,
+                         SourceLocation EllipsisLoc) {
   QualType BaseType = TInfo->getType();
 
   // C++ [class.union]p1:
@@ -475,10 +476,17 @@ Sema::CheckBaseSpecifier(CXXRecordDecl *Class,
     return 0;
   }
 
+  if (EllipsisLoc.isValid() && 
+      !TInfo->getType()->containsUnexpandedParameterPack()) {
+    Diag(EllipsisLoc, diag::err_pack_expansion_without_parameter_packs)
+      << TInfo->getTypeLoc().getSourceRange();
+    EllipsisLoc = SourceLocation();
+  }
+  
   if (BaseType->isDependentType())
     return new (Context) CXXBaseSpecifier(SpecifierRange, Virtual,
                                           Class->getTagKind() == TTK_Class,
-                                          Access, TInfo);
+                                          Access, TInfo, EllipsisLoc);
 
   SourceLocation BaseLoc = TInfo->getTypeLoc().getBeginLoc();
 
@@ -527,7 +535,7 @@ Sema::CheckBaseSpecifier(CXXRecordDecl *Class,
   // Create the base specifier.
   return new (Context) CXXBaseSpecifier(SpecifierRange, Virtual,
                                         Class->getTagKind() == TTK_Class,
-                                        Access, TInfo);
+                                        Access, TInfo, EllipsisLoc);
 }
 
 /// ActOnBaseSpecifier - Parsed a base specifier. A base specifier is
@@ -538,7 +546,8 @@ Sema::CheckBaseSpecifier(CXXRecordDecl *Class,
 BaseResult
 Sema::ActOnBaseSpecifier(Decl *classdecl, SourceRange SpecifierRange,
                          bool Virtual, AccessSpecifier Access,
-                         ParsedType basetype, SourceLocation BaseLoc) {
+                         ParsedType basetype, SourceLocation BaseLoc,
+                         SourceLocation EllipsisLoc) {
   if (!classdecl)
     return true;
 
@@ -550,12 +559,14 @@ Sema::ActOnBaseSpecifier(Decl *classdecl, SourceRange SpecifierRange,
   TypeSourceInfo *TInfo = 0;
   GetTypeFromParser(basetype, &TInfo);
 
-  if (DiagnoseUnexpandedParameterPack(SpecifierRange.getBegin(), TInfo, 
+  if (EllipsisLoc.isInvalid() &&
+      DiagnoseUnexpandedParameterPack(SpecifierRange.getBegin(), TInfo, 
                                       UPPC_BaseType))
     return true;
-
+  
   if (CXXBaseSpecifier *BaseSpec = CheckBaseSpecifier(Class, SpecifierRange,
-                                                      Virtual, Access, TInfo))
+                                                      Virtual, Access, TInfo,
+                                                      EllipsisLoc))
     return BaseSpec;
 
   return true;
diff --git a/clang/lib/Sema/SemaTemplateInstantiate.cpp b/clang/lib/Sema/SemaTemplateInstantiate.cpp
index 8c9681ffd5a..77d3e64a157 100644
--- a/clang/lib/Sema/SemaTemplateInstantiate.cpp
+++ b/clang/lib/Sema/SemaTemplateInstantiate.cpp
@@ -1155,6 +1155,58 @@ Sema::SubstBaseSpecifiers(CXXRecordDecl *Instantiation,
       continue;
     }
 
+    SourceLocation EllipsisLoc;
+    if (Base->isPackExpansion()) {
+      // This is a pack expansion. See whether we should expand it now, or
+      // wait until later.
+      llvm::SmallVector<UnexpandedParameterPack, 2> Unexpanded;
+      collectUnexpandedParameterPacks(Base->getTypeSourceInfo()->getTypeLoc(),
+                                      Unexpanded);
+      bool ShouldExpand = false;
+      unsigned NumExpansions = 0;
+      if (CheckParameterPacksForExpansion(Base->getEllipsisLoc(), 
+                                          Base->getSourceRange(),
+                                          Unexpanded.data(), Unexpanded.size(),
+                                          TemplateArgs, ShouldExpand, 
+                                          NumExpansions)) {
+        continue;
+        Invalid = true;
+      }
+      
+      // If we should expand this pack expansion now, do so.
+      if (ShouldExpand) {
+        for (unsigned I = 0; I != NumExpansions; ++I) {
+            Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(*this, I);
+          
+          TypeSourceInfo *BaseTypeLoc = SubstType(Base->getTypeSourceInfo(),
+                                                  TemplateArgs,
+                                              Base->getSourceRange().getBegin(),
+                                                  DeclarationName());
+          if (!BaseTypeLoc) {
+            Invalid = true;
+            continue;
+          }
+          
+          if (CXXBaseSpecifier *InstantiatedBase
+                = CheckBaseSpecifier(Instantiation,
+                                     Base->getSourceRange(),
+                                     Base->isVirtual(),
+                                     Base->getAccessSpecifierAsWritten(),
+                                     BaseTypeLoc,
+                                     SourceLocation()))
+            InstantiatedBases.push_back(InstantiatedBase);
+          else
+            Invalid = true;
+        }
+      
+        continue;
+      }
+      
+      // The resulting base specifier will (still) be a pack expansion.
+      EllipsisLoc = Base->getEllipsisLoc();
+    }
+    
+    Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(*this, -1);
     TypeSourceInfo *BaseTypeLoc = SubstType(Base->getTypeSourceInfo(),
                                             TemplateArgs,
                                             Base->getSourceRange().getBegin(),
@@ -1169,7 +1221,8 @@ Sema::SubstBaseSpecifiers(CXXRecordDecl *Instantiation,
                                Base->getSourceRange(),
                                Base->isVirtual(),
                                Base->getAccessSpecifierAsWritten(),
-                               BaseTypeLoc))
+                               BaseTypeLoc,
+                               EllipsisLoc))
       InstantiatedBases.push_back(InstantiatedBase);
     else
       Invalid = true;
diff --git a/clang/lib/Sema/SemaTemplateVariadic.cpp b/clang/lib/Sema/SemaTemplateVariadic.cpp
index a3e308fe11f..92df1fd8636 100644
--- a/clang/lib/Sema/SemaTemplateVariadic.cpp
+++ b/clang/lib/Sema/SemaTemplateVariadic.cpp
@@ -294,6 +294,11 @@ void Sema::collectUnexpandedParameterPacks(QualType T,
   CollectUnexpandedParameterPacksVisitor(Unexpanded).TraverseType(T);  
 }  
 
+void Sema::collectUnexpandedParameterPacks(TypeLoc TL,
+                   llvm::SmallVectorImpl<UnexpandedParameterPack> &Unexpanded) {
+  CollectUnexpandedParameterPacksVisitor(Unexpanded).TraverseTypeLoc(TL);  
+}  
+
 ParsedTemplateArgument 
 Sema::ActOnPackExpansion(const ParsedTemplateArgument &Arg,
                          SourceLocation EllipsisLoc) {
diff --git a/clang/lib/Serialization/ASTReader.cpp b/clang/lib/Serialization/ASTReader.cpp
index 084778d856c..dd8807fb004 100644
--- a/clang/lib/Serialization/ASTReader.cpp
+++ b/clang/lib/Serialization/ASTReader.cpp
@@ -4292,7 +4292,9 @@ ASTReader::ReadCXXBaseSpecifier(PerFileData &F,
   AccessSpecifier AS = static_cast<AccessSpecifier>(Record[Idx++]);
   TypeSourceInfo *TInfo = GetTypeSourceInfo(F, Record, Idx);
   SourceRange Range = ReadSourceRange(F, Record, Idx);
-  return CXXBaseSpecifier(Range, isVirtual, isBaseOfClass, AS, TInfo);
+  SourceLocation EllipsisLoc = ReadSourceLocation(F, Record, Idx);
+  return CXXBaseSpecifier(Range, isVirtual, isBaseOfClass, AS, TInfo, 
+                          EllipsisLoc);
 }
 
 std::pair<CXXBaseOrMemberInitializer **, unsigned>
diff --git a/clang/lib/Serialization/ASTWriter.cpp b/clang/lib/Serialization/ASTWriter.cpp
index 8c0fb42f5f8..cbf5ac79192 100644
--- a/clang/lib/Serialization/ASTWriter.cpp
+++ b/clang/lib/Serialization/ASTWriter.cpp
@@ -3231,6 +3231,9 @@ void ASTWriter::AddCXXBaseSpecifier(const CXXBaseSpecifier &Base,
   Record.push_back(Base.getAccessSpecifierAsWritten());
   AddTypeSourceInfo(Base.getTypeSourceInfo(), Record);
   AddSourceRange(Base.getSourceRange(), Record);
+  AddSourceLocation(Base.isPackExpansion()? Base.getEllipsisLoc() 
+                                          : SourceLocation(),
+                    Record);
 }
 
 void ASTWriter::FlushCXXBaseSpecifiers() {
diff --git a/clang/test/CXX/temp/temp.decls/temp.variadic/p4.cpp b/clang/test/CXX/temp/temp.decls/temp.variadic/p4.cpp
index 440bd4b5dbf..49f6993b399 100644
--- a/clang/test/CXX/temp/temp.decls/temp.variadic/p4.cpp
+++ b/clang/test/CXX/temp/temp.decls/temp.variadic/p4.cpp
@@ -34,6 +34,24 @@ void initializer_list_expansion() {
 template void initializer_list_expansion<1, 2, 3, 4, 5>();
 template void initializer_list_expansion<1, 2, 3, 4, 5, 6>(); // expected-note{{in instantiation of function template specialization 'initializer_list_expansion<1, 2, 3, 4, 5, 6>' requested here}}
 
+// In a base-specifier-list (Clause 10); the pattern is a base-specifier.
+template<typename ...Mixins>
+struct HasMixins : public Mixins... { };
+
+struct A { };
+struct B { };
+struct C { };
+struct D { };
+
+A *checkA = new HasMixins<A, B, C, D>;
+B *checkB = new HasMixins<A, B, C, D>;
+D *checkD = new HasMixins<A, B, C, D>;
+C *checkC = new HasMixins<A, B, D>; // expected-error{{cannot initialize a variable of type 'C *' with an rvalue of type 'HasMixins<A, B, D> *'}}
+HasMixins<> *checkNone = new HasMixins<>;
+
+template<typename Mixins>
+struct BrokenMixins : public Mixins... { }; // expected-error{{pack expansion does not contain any unexpanded parameter packs}}
+
 // In a template-argument-list (14.3); the pattern is a template-argument.
 template<typename ...Types>
 struct tuple_of_refs {