1 files changed, 173 insertions, 110 deletions

diff --git a/include/clang/AST/TemplateBase.h b/include/clang/AST/TemplateBase.h
index 7d5123f..a4e074e 100644
--- a/include/clang/AST/TemplateBase.h
+++ b/include/clang/AST/TemplateBase.h
@@ -23,6 +23,7 @@
 
 namespace llvm {
   class FoldingSetNodeID;
+  class raw_ostream;
 }
 
 namespace clang {
@@ -30,26 +31,14 @@ namespace clang {
 class Decl;
 class DiagnosticBuilder;
 class Expr;
+struct PrintingPolicy;
 class TypeSourceInfo;
 
 /// \brief Represents a template argument within a class template
 /// specialization.
 class TemplateArgument {
-  union {
-    uintptr_t TypeOrValue;
-    struct {
-      char Value[sizeof(llvm::APSInt)];
-      void *Type;
-    } Integer;
-    struct {
-      TemplateArgument *Args;
-      unsigned NumArgs;
-      bool CopyArgs;
-    } Args;
-  };
-
 public:
-  /// \brief The type of template argument we're storing.
+  /// \brief The kind of template argument we're storing.
   enum ArgKind {
     /// \brief Represents an empty template argument, e.g., one that has not
     /// been deduced.
@@ -66,16 +55,42 @@ public:
     /// The template argument is a template name that was provided for a 
     /// template template parameter.
     Template,
+    /// The template argument is a pack expansion of a template name that was 
+    /// provided for a template template parameter.
+    TemplateExpansion,
     /// The template argument is a value- or type-dependent expression
     /// stored in an Expr*.
     Expression,
     /// The template argument is actually a parameter pack. Arguments are stored
     /// in the Args struct.
     Pack
-  } Kind;
+  };
+
+private:
+  /// \brief The kind of template argument we're storing.
+  unsigned Kind;
 
+  union {
+    uintptr_t TypeOrValue;
+    struct {
+      char Value[sizeof(llvm::APSInt)];
+      void *Type;
+    } Integer;
+    struct {
+      const TemplateArgument *Args;
+      unsigned NumArgs;
+    } Args;
+    struct {
+      void *Name;
+      unsigned NumExpansions;
+    } TemplateArg;
+  };
+
+  TemplateArgument(TemplateName, bool); // DO NOT USE
+  
+public:
   /// \brief Construct an empty, invalid template argument.
-  TemplateArgument() : TypeOrValue(0), Kind(Null) { }
+  TemplateArgument() : Kind(Null), TypeOrValue(0) { }
 
   /// \brief Construct a template type argument.
   TemplateArgument(QualType T) : Kind(Type) {
@@ -92,6 +107,8 @@ public:
 
   /// \brief Construct an integral constant template argument.
   TemplateArgument(const llvm::APSInt &Value, QualType Type) : Kind(Integral) {
+    // FIXME: Large integral values will get leaked. Do something
+    // similar to what we did with IntegerLiteral.
     new (Integer.Value) llvm::APSInt(Value);
     Integer.Type = Type.getAsOpaquePtr();
   }
@@ -102,10 +119,35 @@ public:
   /// parameters. However, the template name could be a dependent template
   /// name that ends up being instantiated to a function template whose address
   /// is taken.
-  TemplateArgument(TemplateName Name) : Kind(Template) {
-    TypeOrValue = reinterpret_cast<uintptr_t>(Name.getAsVoidPointer());
+  ///
+  /// \param Name The template name.
+  TemplateArgument(TemplateName Name) : Kind(Template) 
+  {
+    TemplateArg.Name = Name.getAsVoidPointer();
+    TemplateArg.NumExpansions = 0;
   }
-  
+
+  /// \brief Construct a template argument that is a template pack expansion.
+  ///
+  /// This form of template argument is generally used for template template
+  /// parameters. However, the template name could be a dependent template
+  /// name that ends up being instantiated to a function template whose address
+  /// is taken.
+  ///
+  /// \param Name The template name.
+  ///
+  /// \param NumExpansions The number of expansions that will be generated by
+  /// instantiating
+  TemplateArgument(TemplateName Name, llvm::Optional<unsigned> NumExpansions)
+    : Kind(TemplateExpansion) 
+  {
+    TemplateArg.Name = Name.getAsVoidPointer();
+    if (NumExpansions)
+      TemplateArg.NumExpansions = *NumExpansions + 1;
+    else
+      TemplateArg.NumExpansions = 0;
+  }
+
   /// \brief Construct a template argument that is an expression.
   ///
   /// This form of template argument only occurs in template argument
@@ -115,46 +157,59 @@ public:
     TypeOrValue = reinterpret_cast<uintptr_t>(E);
   }
 
+  /// \brief Construct a template argument that is a template argument pack.
+  ///
+  /// We assume that storage for the template arguments provided
+  /// outlives the TemplateArgument itself.
+  TemplateArgument(const TemplateArgument *Args, unsigned NumArgs) : Kind(Pack){
+    this->Args.Args = Args;
+    this->Args.NumArgs = NumArgs;
+  }
+
   /// \brief Copy constructor for a template argument.
   TemplateArgument(const TemplateArgument &Other) : Kind(Other.Kind) {
+    // FIXME: Large integral values will get leaked. Do something
+    // similar to what we did with IntegerLiteral.
     if (Kind == Integral) {
       new (Integer.Value) llvm::APSInt(*Other.getAsIntegral());
       Integer.Type = Other.Integer.Type;
     } else if (Kind == Pack) {
       Args.NumArgs = Other.Args.NumArgs;
-      Args.Args = new TemplateArgument[Args.NumArgs];
-      for (unsigned I = 0; I != Args.NumArgs; ++I)
-        Args.Args[I] = Other.Args.Args[I];
-    }
-    else
+      Args.Args = Other.Args.Args;
+    } else if (Kind == Template || Kind == TemplateExpansion) {
+      TemplateArg.Name = Other.TemplateArg.Name;
+      TemplateArg.NumExpansions = Other.TemplateArg.NumExpansions;
+    } else
       TypeOrValue = Other.TypeOrValue;
   }
 
   TemplateArgument& operator=(const TemplateArgument& Other) {
-    // FIXME: Does not provide the strong guarantee for exception
-    // safety.
     using llvm::APSInt;
 
-    // FIXME: Handle Packs
-    assert(Kind != Pack && "FIXME: Handle packs");
-    assert(Other.Kind != Pack && "FIXME: Handle packs");
-
     if (Kind == Other.Kind && Kind == Integral) {
       // Copy integral values.
       *this->getAsIntegral() = *Other.getAsIntegral();
       Integer.Type = Other.Integer.Type;
-    } else {
-      // Destroy the current integral value, if that's what we're holding.
-      if (Kind == Integral)
-        getAsIntegral()->~APSInt();
+      return *this;
+    } 
+
+    // Destroy the current integral value, if that's what we're holding.
+    if (Kind == Integral)
+      getAsIntegral()->~APSInt();
 
-      Kind = Other.Kind;
+    Kind = Other.Kind;
 
-      if (Other.Kind == Integral) {
-        new (Integer.Value) llvm::APSInt(*Other.getAsIntegral());
-        Integer.Type = Other.Integer.Type;
-      } else
-        TypeOrValue = Other.TypeOrValue;
+    if (Other.Kind == Integral) {
+      new (Integer.Value) llvm::APSInt(*Other.getAsIntegral());
+      Integer.Type = Other.Integer.Type;
+    } else if (Other.Kind == Pack) {
+      Args.NumArgs = Other.Args.NumArgs;
+      Args.Args = Other.Args.Args;
+    } else if (Kind == Template || Kind == TemplateExpansion) {
+      TemplateArg.Name = Other.TemplateArg.Name;
+      TemplateArg.NumExpansions = Other.TemplateArg.NumExpansions;
+    } else {
+      TypeOrValue = Other.TypeOrValue;
     }
 
     return *this;
@@ -165,16 +220,31 @@ public:
 
     if (Kind == Integral)
       getAsIntegral()->~APSInt();
-    else if (Kind == Pack && Args.CopyArgs)
-      delete[] Args.Args;
   }
 
+  /// \brief Create a new template argument pack by copying the given set of
+  /// template arguments.
+  static TemplateArgument CreatePackCopy(ASTContext &Context,
+                                         const TemplateArgument *Args,
+                                         unsigned NumArgs);
+  
   /// \brief Return the kind of stored template argument.
-  ArgKind getKind() const { return Kind; }
+  ArgKind getKind() const { return (ArgKind)Kind; }
 
   /// \brief Determine whether this template argument has no value.
   bool isNull() const { return Kind == Null; }
 
+  /// \brief Whether this template argument is dependent on a template
+  /// parameter.
+  bool isDependent() const;
+
+  /// \brief Whether this template argument contains an unexpanded
+  /// parameter pack.
+  bool containsUnexpandedParameterPack() const;
+
+  /// \brief Determine whether this template argument is a pack expansion.
+  bool isPackExpansion() const;
+  
   /// \brief Retrieve the template argument as a type.
   QualType getAsType() const {
     if (Kind != Type)
@@ -195,9 +265,21 @@ public:
     if (Kind != Template)
       return TemplateName();
     
-    return TemplateName::getFromVoidPointer(
-                                        reinterpret_cast<void *> (TypeOrValue));
+    return TemplateName::getFromVoidPointer(TemplateArg.Name);
+  }
+
+  /// \brief Retrieve the template argument as a template name; if the argument
+  /// is a pack expansion, return the pattern as a template name.
+  TemplateName getAsTemplateOrTemplatePattern() const {
+    if (Kind != Template && Kind != TemplateExpansion)
+      return TemplateName();
+    
+    return TemplateName::getFromVoidPointer(TemplateArg.Name);
   }
+
+  /// \brief Retrieve the number of expansions that a template template argument
+  /// expansion will produce, if known.
+  llvm::Optional<unsigned> getNumTemplateExpansions() const;
   
   /// \brief Retrieve the template argument as an integral value.
   llvm::APSInt *getAsIntegral() {
@@ -260,11 +342,17 @@ public:
   /// same.
   bool structurallyEquals(const TemplateArgument &Other) const;
 
-  /// \brief Construct a template argument pack.
-  void setArgumentPack(TemplateArgument *Args, unsigned NumArgs, bool CopyArgs);
+  /// \brief When the template argument is a pack expansion, returns 
+  /// the pattern of the pack expansion.
+  ///
+  /// \param Ellipsis Will be set to the location of the ellipsis.
+  TemplateArgument getPackExpansionPattern() const;
 
+  /// \brief Print this template argument to the given output stream.
+  void print(const PrintingPolicy &Policy, llvm::raw_ostream &Out) const;
+             
   /// \brief Used to insert TemplateArguments into FoldingSets.
-  void Profile(llvm::FoldingSetNodeID &ID, ASTContext &Context) const;
+  void Profile(llvm::FoldingSetNodeID &ID, const ASTContext &Context) const;
 };
 
 /// Location information for a TemplateArgument.
@@ -276,95 +364,48 @@ private:
     struct {
       unsigned QualifierRange[2];
       unsigned TemplateNameLoc;
+      unsigned EllipsisLoc;
     } Template;
   };
 
-#ifndef NDEBUG
-  enum Kind {
-    K_None,
-    K_TypeSourceInfo,
-    K_Expression,
-    K_Template
-  } Kind;
-#endif
-
 public:
-  TemplateArgumentLocInfo()
-    : Expression(0)
-#ifndef NDEBUG
-      , Kind(K_None) 
-#endif
-    {}
+  TemplateArgumentLocInfo();
   
-  TemplateArgumentLocInfo(TypeSourceInfo *TInfo)
-    : Declarator(TInfo)
-#ifndef NDEBUG
-      , Kind(K_TypeSourceInfo) 
-#endif
-    {}
+  TemplateArgumentLocInfo(TypeSourceInfo *TInfo) : Declarator(TInfo) {}
   
-  TemplateArgumentLocInfo(Expr *E)
-    : Expression(E)
-#ifndef NDEBUG
-      , Kind(K_Expression) 
-#endif
-    {}
+  TemplateArgumentLocInfo(Expr *E) : Expression(E) {}
   
   TemplateArgumentLocInfo(SourceRange QualifierRange, 
-                          SourceLocation TemplateNameLoc)
-#ifndef NDEBUG
-    : Kind(K_Template)
-#endif
+                          SourceLocation TemplateNameLoc,
+                          SourceLocation EllipsisLoc)
   {
     Template.QualifierRange[0] = QualifierRange.getBegin().getRawEncoding();
     Template.QualifierRange[1] = QualifierRange.getEnd().getRawEncoding();
     Template.TemplateNameLoc = TemplateNameLoc.getRawEncoding();
+    Template.EllipsisLoc = EllipsisLoc.getRawEncoding();
   }
 
   TypeSourceInfo *getAsTypeSourceInfo() const {
-    assert(Kind == K_TypeSourceInfo);
     return Declarator;
   }
 
   Expr *getAsExpr() const {
-    assert(Kind == K_Expression);
     return Expression;
   }
 
   SourceRange getTemplateQualifierRange() const {
-    assert(Kind == K_Template);
     return SourceRange(
                 SourceLocation::getFromRawEncoding(Template.QualifierRange[0]),
                 SourceLocation::getFromRawEncoding(Template.QualifierRange[1]));
   }
   
   SourceLocation getTemplateNameLoc() const {
-    assert(Kind == K_Template);
     return SourceLocation::getFromRawEncoding(Template.TemplateNameLoc);
   }
   
-#ifndef NDEBUG
-  void validateForArgument(const TemplateArgument &Arg) {
-    switch (Arg.getKind()) {
-    case TemplateArgument::Type:
-      assert(Kind == K_TypeSourceInfo);
-      break;
-    case TemplateArgument::Expression:
-    case TemplateArgument::Declaration:
-      assert(Kind == K_Expression);
-      break;
-    case TemplateArgument::Template:
-      assert(Kind == K_Template);
-      break;
-    case TemplateArgument::Integral:
-    case TemplateArgument::Pack:
-      assert(Kind == K_None);
-      break;
-    case TemplateArgument::Null:
-      llvm_unreachable("source info for null template argument?");
-    }
+  SourceLocation getTemplateEllipsisLoc() const {
+    return SourceLocation::getFromRawEncoding(Template.EllipsisLoc);
   }
-#endif
 };
 
 /// Location wrapper for a TemplateArgument.  TemplateArgument is to
@@ -393,14 +434,18 @@ public:
 
   TemplateArgumentLoc(const TemplateArgument &Argument, 
                       SourceRange QualifierRange,
-                      SourceLocation TemplateNameLoc)
-    : Argument(Argument), LocInfo(QualifierRange, TemplateNameLoc) {
-    assert(Argument.getKind() == TemplateArgument::Template);
+                      SourceLocation TemplateNameLoc,
+                      SourceLocation EllipsisLoc = SourceLocation())
+    : Argument(Argument), 
+      LocInfo(QualifierRange, TemplateNameLoc, EllipsisLoc) {
+    assert(Argument.getKind() == TemplateArgument::Template ||
+           Argument.getKind() == TemplateArgument::TemplateExpansion);
   }
   
   /// \brief - Fetches the primary location of the argument.
   SourceLocation getLocation() const {
-    if (Argument.getKind() == TemplateArgument::Template)
+    if (Argument.getKind() == TemplateArgument::Template ||
+        Argument.getKind() == TemplateArgument::TemplateExpansion)
       return getTemplateNameLoc();
     
     return getSourceRange().getBegin();
@@ -433,14 +478,32 @@ public:
   }
   
   SourceRange getTemplateQualifierRange() const {
-    assert(Argument.getKind() == TemplateArgument::Template);
+    assert(Argument.getKind() == TemplateArgument::Template ||
+           Argument.getKind() == TemplateArgument::TemplateExpansion);
     return LocInfo.getTemplateQualifierRange();
   }
   
   SourceLocation getTemplateNameLoc() const {
-    assert(Argument.getKind() == TemplateArgument::Template);
+    assert(Argument.getKind() == TemplateArgument::Template ||
+           Argument.getKind() == TemplateArgument::TemplateExpansion);
     return LocInfo.getTemplateNameLoc();
   }  
+  
+  SourceLocation getTemplateEllipsisLoc() const {
+    assert(Argument.getKind() == TemplateArgument::TemplateExpansion);
+    return LocInfo.getTemplateEllipsisLoc();
+  }
+  
+  /// \brief When the template argument is a pack expansion, returns 
+  /// the pattern of the pack expansion.
+  ///
+  /// \param Ellipsis Will be set to the location of the ellipsis.
+  ///
+  /// \param NumExpansions Will be set to the number of expansions that will
+  /// be generated from this pack expansion, if known a priori.
+  TemplateArgumentLoc getPackExpansionPattern(SourceLocation &Ellipsis,
+                                        llvm::Optional<unsigned> &NumExpansions,
+                                              ASTContext &Context) const;
 };
 
 /// A convenient class for passing around template argument