Implement pack expansion of base initializers, so that we can

initialize those lovely mixins that come from pack expansions of base
specifiers.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@122793 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 109 insertions, 10 deletions

diff --git a/lib/Sema/SemaDeclCXX.cpp b/lib/Sema/SemaDeclCXX.cpp
index 10d04fa9a3..e2067de964 100644
--- a/lib/Sema/SemaDeclCXX.cpp
+++ b/lib/Sema/SemaDeclCXX.cpp
@@ -1057,7 +1057,8 @@ Sema::ActOnMemInitializer(Decl *ConstructorD,
                           SourceLocation IdLoc,
                           SourceLocation LParenLoc,
                           ExprTy **Args, unsigned NumArgs,
-                          SourceLocation RParenLoc) {
+                          SourceLocation RParenLoc,
+                          SourceLocation EllipsisLoc) {
   if (!ConstructorD)
     return true;
 
@@ -1093,15 +1094,26 @@ Sema::ActOnMemInitializer(Decl *ConstructorD,
     if (Result.first != Result.second) {
       Member = dyn_cast<FieldDecl>(*Result.first);
     
-      if (Member)
+      if (Member) {
+        if (EllipsisLoc.isValid())
+          Diag(EllipsisLoc, diag::err_pack_expansion_member_init)
+            << MemberOrBase << SourceRange(IdLoc, RParenLoc);
+        
         return BuildMemberInitializer(Member, (Expr**)Args, NumArgs, IdLoc,
                                     LParenLoc, RParenLoc);
+      }
+      
       // Handle anonymous union case.
       if (IndirectFieldDecl* IndirectField
-            = dyn_cast<IndirectFieldDecl>(*Result.first))
+            = dyn_cast<IndirectFieldDecl>(*Result.first)) {
+        if (EllipsisLoc.isValid())
+          Diag(EllipsisLoc, diag::err_pack_expansion_member_init)
+            << MemberOrBase << SourceRange(IdLoc, RParenLoc);
+
          return BuildMemberInitializer(IndirectField, (Expr**)Args,
                                        NumArgs, IdLoc,
                                        LParenLoc, RParenLoc);
+      }
     }
   }
   // It didn't name a member, so see if it names a class.
@@ -1210,7 +1222,7 @@ Sema::ActOnMemInitializer(Decl *ConstructorD,
     TInfo = Context.getTrivialTypeSourceInfo(BaseType, IdLoc);
 
   return BuildBaseInitializer(BaseType, TInfo, (Expr **)Args, NumArgs, 
-                              LParenLoc, RParenLoc, ClassDecl);
+                              LParenLoc, RParenLoc, ClassDecl, EllipsisLoc);
 }
 
 /// Checks an initializer expression for use of uninitialized fields, such as
@@ -1383,7 +1395,8 @@ MemInitResult
 Sema::BuildBaseInitializer(QualType BaseType, TypeSourceInfo *BaseTInfo,
                            Expr **Args, unsigned NumArgs, 
                            SourceLocation LParenLoc, SourceLocation RParenLoc, 
-                           CXXRecordDecl *ClassDecl) {
+                           CXXRecordDecl *ClassDecl,
+                           SourceLocation EllipsisLoc) {
   bool HasDependentArg = false;
   for (unsigned i = 0; i < NumArgs; i++)
     HasDependentArg |= Args[i]->isTypeDependent();
@@ -1403,6 +1416,24 @@ Sema::BuildBaseInitializer(QualType BaseType, TypeSourceInfo *BaseTInfo,
   //   name that denotes that base class type.
   bool Dependent = BaseType->isDependentType() || HasDependentArg;
 
+  if (EllipsisLoc.isValid()) {
+    // This is a pack expansion.
+    if (!BaseType->containsUnexpandedParameterPack())  {
+      Diag(EllipsisLoc, diag::err_pack_expansion_without_parameter_packs)
+        << SourceRange(BaseLoc, RParenLoc);
+      
+      EllipsisLoc = SourceLocation();
+    }
+  } else {
+    // Check for any unexpanded parameter packs.
+    if (DiagnoseUnexpandedParameterPack(BaseLoc, BaseTInfo, UPPC_Initializer))
+      return true;
+    
+    for (unsigned I = 0; I != NumArgs; ++I)
+      if (DiagnoseUnexpandedParameterPack(Args[I]))
+        return true;
+  }
+  
   // Check for direct and virtual base classes.
   const CXXBaseSpecifier *DirectBaseSpec = 0;
   const CXXBaseSpecifier *VirtualBaseSpec = 0;
@@ -1447,7 +1478,8 @@ Sema::BuildBaseInitializer(QualType BaseType, TypeSourceInfo *BaseTInfo,
                                                     /*IsVirtual=*/false,
                                                     LParenLoc, 
                                                     BaseInit.takeAs<Expr>(),
-                                                    RParenLoc);
+                                                    RParenLoc,
+                                                    EllipsisLoc);
   }
 
   // C++ [base.class.init]p2:
@@ -1501,14 +1533,16 @@ Sema::BuildBaseInitializer(QualType BaseType, TypeSourceInfo *BaseTInfo,
                                                     BaseSpec->isVirtual(),
                                                     LParenLoc, 
                                                     Init.takeAs<Expr>(),
-                                                    RParenLoc);
+                                                    RParenLoc,
+                                                    EllipsisLoc);
   }
 
   return new (Context) CXXBaseOrMemberInitializer(Context, BaseTInfo,
                                                   BaseSpec->isVirtual(),
                                                   LParenLoc, 
                                                   BaseInit.takeAs<Expr>(),
-                                                  RParenLoc);
+                                                  RParenLoc,
+                                                  EllipsisLoc);
 }
 
 /// ImplicitInitializerKind - How an implicit base or member initializer should
@@ -1586,6 +1620,7 @@ BuildImplicitBaseInitializer(Sema &SemaRef, CXXConstructorDecl *Constructor,
                                              BaseSpec->isVirtual(),
                                              SourceLocation(),
                                              BaseInit.takeAs<Expr>(),
+                                             SourceLocation(),
                                              SourceLocation());
 
   return false;
diff --git a/lib/Sema/SemaTemplateInstantiate.cpp b/lib/Sema/SemaTemplateInstantiate.cpp
index 77d3e64a15..16500d4207 100644
--- a/lib/Sema/SemaTemplateInstantiate.cpp
+++ b/lib/Sema/SemaTemplateInstantiate.cpp
@@ -1169,8 +1169,8 @@ Sema::SubstBaseSpecifiers(CXXRecordDecl *Instantiation,
                                           Unexpanded.data(), Unexpanded.size(),
                                           TemplateArgs, ShouldExpand, 
                                           NumExpansions)) {
-        continue;
         Invalid = true;
+        continue;
       }
       
       // If we should expand this pack expansion now, do so.
diff --git a/lib/Sema/SemaTemplateInstantiateDecl.cpp b/lib/Sema/SemaTemplateInstantiateDecl.cpp
index 9db3a8cacf..60a942ac2f 100644
--- a/lib/Sema/SemaTemplateInstantiateDecl.cpp
+++ b/lib/Sema/SemaTemplateInstantiateDecl.cpp
@@ -2362,6 +2362,69 @@ Sema::InstantiateMemInitializers(CXXConstructorDecl *New,
     SourceLocation LParenLoc, RParenLoc;
     ASTOwningVector<Expr*> NewArgs(*this);
 
+    SourceLocation EllipsisLoc;
+    
+    if (Init->isPackExpansion()) {
+      // This is a pack expansion. We should expand it now.
+      TypeLoc BaseTL = Init->getBaseClassInfo()->getTypeLoc();
+      llvm::SmallVector<UnexpandedParameterPack, 2> Unexpanded;
+      collectUnexpandedParameterPacks(BaseTL, Unexpanded);
+      bool ShouldExpand = false;
+      unsigned NumExpansions = 0;
+      if (CheckParameterPacksForExpansion(Init->getEllipsisLoc(), 
+                                          BaseTL.getSourceRange(),
+                                          Unexpanded.data(), 
+                                          Unexpanded.size(),
+                                          TemplateArgs, ShouldExpand, 
+                                          NumExpansions)) {
+        AnyErrors = true;
+        New->setInvalidDecl();
+        continue;
+      }
+      assert(ShouldExpand && "Partial instantiation of base initializer?");
+      
+      // Loop over all of the arguments in the argument pack(s), 
+      for (unsigned I = 0; I != NumExpansions; ++I) {
+        Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(*this, I);
+
+        // Instantiate the initializer.
+        if (InstantiateInitializer(*this, Init->getInit(), TemplateArgs, 
+                                   LParenLoc, NewArgs, RParenLoc)) {
+          AnyErrors = true;
+          break;
+        }
+
+        // Instantiate the base type.
+        TypeSourceInfo *BaseTInfo = SubstType(Init->getBaseClassInfo(), 
+                                              TemplateArgs, 
+                                              Init->getSourceLocation(), 
+                                              New->getDeclName());
+        if (!BaseTInfo) {
+          AnyErrors = true;
+          break;
+        }
+
+        // Build the initializer.
+        MemInitResult NewInit = BuildBaseInitializer(BaseTInfo->getType(), 
+                                                     BaseTInfo,
+                                                     (Expr **)NewArgs.data(),
+                                                     NewArgs.size(),
+                                                     Init->getLParenLoc(),
+                                                     Init->getRParenLoc(),
+                                                     New->getParent(),
+                                                     SourceLocation());
+        if (NewInit.isInvalid()) {
+          AnyErrors = true;
+          break;
+        }
+        
+        NewInits.push_back(NewInit.get());
+        NewArgs.clear();
+      }
+      
+      continue;
+    }
+
     // Instantiate the initializer.
     if (InstantiateInitializer(*this, Init->getInit(), TemplateArgs, 
                                LParenLoc, NewArgs, RParenLoc)) {
@@ -2386,7 +2449,8 @@ Sema::InstantiateMemInitializers(CXXConstructorDecl *New,
                                      NewArgs.size(),
                                      Init->getLParenLoc(),
                                      Init->getRParenLoc(),
-                                     New->getParent());
+                                     New->getParent(),
+                                     EllipsisLoc);
     } else if (Init->isMemberInitializer()) {
       FieldDecl *Member = cast<FieldDecl>(FindInstantiatedDecl(
                                                      Init->getMemberLocation(),